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  • Springer  (173,866)
  • 2020-2020
  • 2000-2004  (173,866)
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Year
  • 1
    Unknown
    The Conversion of Liquid Rocket Fuels : Risk Assessment, Technology and Treatment Options for the Conversion of Abandoned Liquid Ballistic Missile Propellants (Fuels and Oxidizers) in Azerbaijan (2004)
    Springer
    Details
    Description / Table of Contents: Prof. Dr. -Ing. Wolfgang Spyra Brandenburg University of Technology in Cottbus, Germany The demilitarization and conversion of military properties wor- wide has been a topic of growing importance since the end of the Cold War. The slowing of the arms race brought on by weapons treaties and relaxed tensions between NATO and Warsaw Pact nations caused sto- piles of conventional weapons to become superfluous. The need to process and dispose of such weapons began more quickly in NATO countries. This demilitarization process began shortly after the reunification of Germany and was largely completed by the mid to late 1990’s. The remaining process, no small task in itself, of converting lands formerly used by the military into safe and environmentally acceptable landscapes may continue for decades to come. Due to a lack of resources and technology, the process of demilitarization in the former Warsaw Pact countries has launched more slowly. In 2002 both Georgia and Moldova finished projects which destroyed their stocks of liquid ballistic missile components. Both these projects were carried out through the cooperative support of trans-national organizations, private contractors, and research institutions. The Republic of Azerbaijan now finds itself at the beginning of its demilitarization process. Stored at the country’s military depots are over 2000 tons of missile fuels, oxidizer, and chemical additives. This hazardous waste is kept in tanks intended only for temporary transport and storage.
    Pages: Online-Ressource (X, 148 pages)
    ISBN: 9781402023811
    URL: https://doi.org/10.1007/1-4020-2381-2
    Language: English
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  • 2
    Unknown
    Effects of Space Weather on Technology Infrastructure : Proceedings of the NATO ARW on Effects of Space Weather on Technology Infrastructure, Rhodes, Greece, from 25 to 29 March 2003. (2004)
    Springer
    Details
    Keywords: communication ; design ; dynamics ; environment ; network ; physics ; power transmission ; radio ; satellite ; simulation ; technology ; transmission
    Description / Table of Contents: The 17 chapters of this book grew out of the tutorial lectures given by leading world-class experts at the NATO Advanced Research Workshop “Effects of Space Weather on Technology Infrastructure” - ESPRIT, which was held in Rhodes on March 25-29, 2004. All manuscripts were refereed and subsequently meticulously edited by the editor to ensure the highest quality for this monograph. I owe particular thanks to the lecturers of the ESPRIT Advanced Research Workshop for producing these excellent tutorial reviews, which convey the essential knowledge and the latest advances in our field. Due to the breadth, extensive literature citations and quality of the reviews we expect this publication to serve extremely well as a reference book. Multimedia material referring to individual chapters of the book is accessible on the accompanying CD. The aim of ESPRIT was to assess existing knowledge and identify future actions regarding monitoring, forecasting and mitigation of space weather induced malfunction and damage of vital technological systems operating in space and on the ground.
    ISBN: 9781402027543
    URL: https://doi.org/10.1007/1-4020-2754-0
    Language: English
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  • 3
    Unknown
    Strategic decision making : applying the analytic hierarchy process (2004)
    London ; New York : Springer
    Decision engineering  
    Details
    Keywords: Decision making, Mathematical models. ; Decision making, Methodology.
    Pages: ix, 172 p.
    ISBN: 1-85233-864-4
    URL: http://www.netLibrary.com/urlapi.asp?action=summary&v=1&bookid=108180
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    E-Book (German National Licenses)
  • 4
    Unknown
    Web services, E-Business, and the Semantic Web : second international workshop, WES 2003, Klagenfurt, Austria, June 16-17, 2003 ; WES 2003 (2004)
    Berlin ; New York : Springer
    Lecture notes in computer science  
    Details
    Keywords: Semantic Web, Congresses.
    Pages: x, 145 p.
    ISBN: 3-540-25982-1
    URL: http://www.netLibrary.com/urlapi.asp?action=summary&v=1&bookid=130186
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  • 5
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    Lattice-Gas Cellular Automata and Lattice Boltzmann Models - An Introduction (2000)
    Springer
    In:  EPIC3Springer, Berlinpp. (Lecture Notes in Mathematics ; 1725) Remark (September 2002): The original edition is now out of print. A slightly revised version (compare `Errata' and `Additions' under: {http://www.awi-bremerhaven.de/Modelling/LGCA+LBM/} is availab, Berlin, Springer, 308, 308 p., ISBN: 3-540-66973-6
    Details
    Publication Date: 2019-07-17
    Description: Lattice-gas cellular automata (LGCA) and lattice Boltzmann models (LBM) are relatively new andpromising methods for the numerical solution of nonlinear partial differential equations. The bookprovides an introduction for graduate students and researchers. Working knowledge of calculus isrequired and experience in PDEs and fluid dynamics is recommended. Some peculiarities of cellularautomata are outlined in Chapter 2. The properties of various LGCA and special coding techniquesare discussed in Chapter 3. Concepts from statistical mechanics (Chapter 4) provide the necessarytheoretical background for LGCA and LBM. The properties of lattice Boltzmann models and amethod for their construction are presented in Chapter 5.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Book , peerRev
    Format: application/pdf
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  • 6
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    Early warning systems for natural disaster reduction (2003)
    Springer
    Details
    Publication Date: 2020-02-12
    Keywords: 550 - Earth sciences
    Type: info:eu-repo/semantics/book
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  • 7
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    GPS : theory, algorithms and applications (2003)
    Springer
    Details
    Publication Date: 2020-02-12
    Keywords: 550 - Earth sciences
    Type: info:eu-repo/semantics/book
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of "spraying" by fighting honey bee queens (Apis mellifera L.) on the temporal structure of fights (2000)
    Springer
    Insectes sociaux 47 (2000), S. 21-26 
    Details
    ISSN: 1420-9098
    Keywords: Key words:Apis, honey bee, conflict, pheromone, fighting behaviour, colony founding.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Young queens start a new colony either without (independently) or with the help of workers (dependently). When colony reproduction is dependent and young queens are produced in excess, conflicts among queens are predicted to occur. Honey bee colonies reproduce dependently by swarming. The mother queen leaves with a "prime swarm" before daughter queens reach adulthood. Several young queens are produced, and often fight to death after emergence. Surviving queen(s) inherit the established nest or a portion of workers which then depart in an "afterswarm". Honey bee queens show traits considered to be adaptations for fighting and conflict with other queens, such as early venom production and fast development. During fights one of the queens often releases rectal fluid. The function of this "spraying" behaviour is unclear. Possible functions of spraying are to affect worker intervention in fights, to act as a chemical weapon, or to interrupt fights. We staged fights between 24 queen pairs to investigate the temporal pattern of behaviour in spraying and non-spraying fights. Spraying occurred in 67% of the fights, usually upon physical contact, and it resulted in at least temporary separation of the queens in 81% of the spraying fights. Spraying fights were characterized by a significantly lower proportion of time spent in escalated aggression than non-spraying fights and a significantly shorter first escalated bout. This provides quantitative evidence that spraying interrupts fights and suggests that its function is to provide a temporary respite to the spraying queen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000400050004
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  • 9
    Electronic Resource
    Electronic Resource
    Food habits of Aenictus army ants and their effects on the ant community in a rain forest of Borneo (2000)
    Springer
    Insectes sociaux 47 (2000), S. 42-49 
    Details
    ISSN: 1420-9098
    Keywords: Key words:Aenictus, army ants, ant community, Borneo.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: In a rain forest at the foot of Mt. Kinabalu, Borneo, we observed the food habits of Aenictus laeviceps and A. gracilis and surveyed the effects of A. laeviceps on the general ant community. We collected totals of 2,360 and 6,268 prey units, respectively, from seven A. laeviceps and six A. gracilis colonies; ants constituted 99.9% of all prey units. Dominant prey genera were Camponotus (48.2% in wet weight), Pseudolasius (20.8%), and Polyrhachis (15.2%) in A. laeviceps and Technomymex (52.1%), Paratrechina (22.4%), and Crematogaster (11.9%) in A. gracilis. A. laeviceps primarily hunted larger ground ants with small- or medium-sized colonies; in contrast, A. gracilis frequently foraged on smaller arboreal ants with larger colonies. Of the total wet weight of prey ants, brood constituted 88.7% in A. laeviceps and only 68.7% in A. gracilis. This was probably because workers of A. gracilis were quicker in behavior and hunted adult workers more frequently than A. laeviceps. While 98.5% of the prey units were transported by single workers of A. gracilis, 71.5% were carried by up to 20 A. laeviceps workers. The numbers of ant colonies and species were significantly smaller in laeviceps-raided quadrats than in controls. This was mostly due to the escape of ants that nested under litter and had relatively larger colonies. Large colonies usually influence the foundation and establishment of incipient small colonies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000400050007
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  • 10
    Electronic Resource
    Electronic Resource
    Changes in worker polymorphism in Myrmicaria opaciventris Emery (Formicidae, Myrmicinae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 50-55 
    Details
    ISSN: 1420-9098
    Keywords: Key words: Colony founding, polymorphism, Myrmicinae, Myrmicaria opaciventris.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The colony ontogeny of Myrmicaria opaciventris was studied by comparing worker number and worker size in foundations with one queen (haplometrosis) or 2 to 6 queens (pleometrosis) and in established colonies. Measurements taken of head width related to scape length showed that the worker caste is weakly polymorphic and exhibits a unimodal size distribution. Classically, the first workers produced in both types of foundations are smaller than those emerging later. Moreover, the worker caste allometry changes with the type of foundation and the age of colony: it varies from a negative allometry for haplometrotic foundations to a stage of isometry in pleometrotic foundations and finally a positive allometry for established colonies. The number of workers produced by the queens is classically larger in pleometrotic than in haplometrotic foundations. However, two uncommon phenomena are described in this species: (1) queen association during colony founding increases their individual fecundity; and (2) the workers produced differ in size and allometry according to the type of foundation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000400050008
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  • 11
    Electronic Resource
    Electronic Resource
    Genetic structure of colonies and a male aggregation in the stingless bee Scaptotrigona postica, as revealed by microsatellite analysis (2000)
    Springer
    Insectes sociaux 47 (2000), S. 63-69 
    Details
    ISSN: 1420-9098
    Keywords: Key words: Meliponinae, monandry, polyandry, relatedness, congregation.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Stingless bee queens have for long been assumed to mate once on a nuptial flight, early in life. To evaluate critically monandry in one stingless bee, Scaptotrigona postica, worker offspring (adults or brood) were genetically analysed with microsatellite loci, five of which were developed specifically for the species. Marker loci were highly variable; unbiased estimates of heterozygosity were 〉 0.5. "Foreign" workers, either those having drifted from other colonies (circa 2%) or those of a replacement queen, were identified with the genetic markers and removed from further analysis. Worker genotypes were consistent with some queens having mated once and others having mated with up to six different males. Scaptotrigona postica queens are therefore facultatively polyandrous. Effective mating frequencies, m e , were generally lower than the number of patrilines observed. Relatedness estimates of nestmates from individual colonies concurred with those derived from direct counts of the number of patrilines and their proportional representation. Putative genotypes of a colony's queen and her mates were deduced from those of her workers. Queens were generally not related to their mates. For one polyandrous queen, her six mates were related to each other, possibly because of numerically biased representation of males from different colonies at mating sites. However, males at an aggregation outside a colony came from numerous colonies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000400050010
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  • 12
    Electronic Resource
    Electronic Resource
    Raiding and emigration dynamics in the ponerine army ant Leptogenys distinguenda (Hymenoptera, Formicidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 76-83 
    Details
    ISSN: 1420-9098
    Keywords: Key words:Leptogenys distinguenda, army ants, raids, emigration.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Field and laboratory observations demonstrate that Leptogenys distinguenda is characterized by typical army ant behavior. Like in the "classical" army ants from the subfamilies Ecitoninae, Dorylinae and Aenictinae, raiding and emigration behavior are closely linked. The direction of raids can be altered in field experiments to a wide extent by offering ample food, suggesting it is highly influenced by the patchiness of prey. The sum of recruitments coming from one direction and the recruitment overrun are primarily responsible for the spatial development and the extension of raids. Emigration frequency can be suppressed by overfeeding a colony in the field. This result is interpreted as a secondary effect of reduced swarming activity, which gets suppressed as well in the same experiment. The discovery of a suitable nest site is considered the proximate stimulus for emigration, and the best explored areas are those that have been most thoroughly raided. As a result, emigrations are likely to lead into areas with high prey densities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000400050012
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  • 13
    Electronic Resource
    Electronic Resource
    Prey concealment and spatiotemporal patrolling behaviour of the Indian tree ant Oecophylla smaragdina (Fabricius) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 92-93 
    Details
    ISSN: 1420-9098
    Keywords: Key words:Oecophylla smaragdina, prey concealment, spatiotemporal patrolling.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Oecophylla smaragdina workers conceal prey with leaves and twigs on discovering large prey on their ground territory. The prey concealment behaviour occurs concurrently with prey capture and killing. Ants were observed conducting spatiotemporal patrolling around large prey. The garden lizard Calotes versicolor and at least two predatory ant species were found to forage in the same area as O. smaragdina. It is suggested that the prey concealment behaviour of Oecophylla may be a strategy to prevent prey detection by vertebrate predators which use vision to prey on similar large prey species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000400050014
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  • 14
    Electronic Resource
    Electronic Resource
    Colony relatedness in aggregations of Apis dorsata Fabricius (Hymenoptera, Apidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 94-95 
    Details
    ISSN: 1420-9098
    Keywords: Key words: Relatedness, swarming, aggregations, migration, Apis dorsata.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Apis dorsata colonies often form dense aggregations, with over 100 colonies sometimes seen in the same tree. Reasons for these aggregations are unknown, but one reasonable hypothesis is that colonies form a related family group. Here we show that 7 adjacent colonies sampled from a single branch of a tree (near Alor Setar in northern peninsular Malaysia) containing over 120 colonies were not related as mother/daughter. Thus the notion that aggregations arise through splitting of the first-arriving colonies can be rejected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000400050015
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  • 15
    Electronic Resource
    Electronic Resource
    Genetical and morphological colony structure of the Australian swarm-founding polistine wasp, Ropalidia romandi (Hymenoptera, Vespidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 113-116 
    Details
    ISSN: 1420-9098
    Keywords: Key words: Wasps, swarm-founding, relatedness, queen number, Ropalidia romandi.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Genetical colony structure of an Australian swarm-founding polistine wasp, Ropalidia romandi, was analyzed. Inseminated females with developed ovaries (egg-layers) tended to have larger body size (measured at the median cell of the forewing) than non egg-layers. Two way ANOVA revealed that the difference in body size was related to both the caste and the colony of origin. The genetic relatedness among egg-layers as detected by electrophoresis was 0.336 ± 0.114 (mean ± se), and that among non egg-layers was 0.161 ± 0.035. The inbreeding coefficient among non egg-layers was found to be significantly greater than zero, but this did not seem to play a major part in the increase in relatedness among progeny. The number of effective queens (mothers of new queens) was estimated to be 2.84 per colony. This number is much smaller than the actual counts of queens. This discrepancy is discussed in terms of possibilities that wasps practice cyclical oligogyny, matriline localization within a colony, and genotypic behavioral specialization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00001688
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  • 16
    Electronic Resource
    Electronic Resource
    Contributions to the life history of the Malaysian giant ant Camponotus gigas (Hymenoptera, Formicidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 123-132 
    Details
    ISSN: 1420-9098
    Keywords: Key words: Formicidae, polydomy, ecology, social structure, rain forest canopy.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: We studied 4 polydomous colonies of the giant ant Camponotus gigas living on ca. 5 ha of primary rain forest in Borneo. Colony structure was flexible, comprising between 8 and 14 mostly subterranean nests. During the course of the study some nests were abandoned and others were established. Colonies appeared territorial with nests being connected by trails through the forest canopy. The best studied colony had a territory of 0.8 ha and a population of ca. 7000 workers, distributed unevenly among an average of 11 nests. Workers were bimorphic, majors on average weighed 372 mg and minors 135 mg. The castes differed in the morphology particularly by allometric growth of the head (mean head width 6.93 mm and 3.56 mm).¶Foraging was mainly nocturnal. At dusk large numbers of foragers (between 35 and 2287 left single nests within 75 minutes of the onset of foraging) invaded the canopy, many workers commuting between the canopy and the nests and all returning home by dawn. During the daytime foraging was reduced and was restricted to a much smaller number of workers which roamed the forest floor. C. gigas foragers collected mainly honeydew (90%) with the remainder consisting of insect prey and bird droppings. Hunting success was increased by rainfall. The numbers of foragers in each nest frequently changed naturally, but could be manipulated by altering local food supply.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00001690
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  • 17
    Electronic Resource
    Electronic Resource
    Nutritional function of replete workers in the pharaoh's ant, Monomorium pharaonis (L.) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 141-146 
    Details
    ISSN: 1420-9098
    Keywords: Key words: Social regulation, liquid food storage, egg production, queen fecundity, larval secretions.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Queens of the pharaoh's ant Monomorium pharaonis (L.), like several other ant species, feed on larval secretions as their main nourishment and their fecundity is positively correlated with the number of large larvae present in the nest. The surplus of secretions produced by larvae is stored in a temporary caste of replete workers, which comprises young workers who remain in the nest and store liquid nourishment. Repletes are characterised by a conspicuously large gaster, caused by large amounts of liquid food stored in the crop, from which it may be regurgitated and distributed among colony members. In this study, repletes of pharaoh's ants were demonstrated to be functioning as buffers, smoothing fluctuations in availability of high quality food to the reproductive queens when larvae are scarce or missing, thus temporarily keeping up the egg production of queens.¶In undisturbed two-queen colonies with 20 large worker larvae and 30 workers (15 young and 15 old workers), approximately 10 repletes developed (one replete per two larvae). Development of older workers into repletes, when some or all repletes had been removed from the colonies, demonstrated that their temporal polyethism exhibits great plasticity in this trait.¶This study confirmed that, in pharaoh's ants, the regulation of fecundity depends not only on the food flow to the queen from larvae or from repletes but also on an unknown larval stimulus.¶The term crop repletes is suggested for replete workers which use their crop to store nourishment, as opposed to fat-body repletes, which store nourishment in their fat body.¶The presence of brood tending crop repletes in nests in several European ant species of Leptothorax, Myrmica, and Lasius, show that repletism is a common trait in ants, and that it may play an important role in regulation of nutrition in ant colonies, as demonstrated in Monomorium pharaonis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00001692
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  • 18
    Electronic Resource
    Electronic Resource
    Dominance hierarchy in colonies of Belonogaster juncea juncea (Vespidae, Polistinae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 158-163 
    Details
    ISSN: 1420-9098
    Keywords: Key words: Dominance hierarchy, linearity, Belonogaster, Polistinae.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Dominance behaviours and the structure of the dominance hierarchy in colonies of Belonogaster juncea juncea are described. The frequency of these behaviours was recorded for each individual by noting "all occurrences of rare behaviours". Among the dominance behaviours recorded, the most frequent was "grappling," which represents 69.8 % of the total number of dominance interactions observed. The overall frequency of dominance behaviours was 0.4 ± 0.36 and 2.99 ± 1.97 per hour per individual in pre- and post-emergence colonies, respectively. The data were submitted to the Appleby test, which shows the hierarchy's highly significant level of linearity. The a female showed the highest frequency of dominance interactions and initiated 81.5 % and 48.8 % of the total dominance interactions observed in pre- and post-emergence colonies, respectively. A weekly record of the frequency of dominance interactions throughout the biological cycle shows that this frequency was highest before or immediately after the disappearance of the dominant female. The most aggressive dominance behaviour (falling fights) was observed only during the weeks after the dominant's departure. This behaviour is thus involved in the establishment of the hierarchy and not in its maintenance, which is accomplished by means of less aggressive behaviours.
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    URL: http://dx.doi.org/10.1007/PL00001695
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  • 19
    Electronic Resource
    Electronic Resource
    Single and dual parasitic mite infestations on the honey bee, Apis mellifera L. (2000)
    Springer
    Insectes sociaux 47 (2000), S. 171-176 
    Details
    ISSN: 1420-9098
    Keywords: Key words:Varroa jacobsoni, Acarapis woodi, colony state, foraging behavior, host selection.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The onset of foraging, proportion of pollen collectors, and weight of pollen loads were compared in individual honey bees (Apis mellifera) infested by zero, one (Acarapis woodi, the honey bee tracheal mite, or Varroa jacobsoni,varroa), or both species of parasitic mites. Phoretic varroa host choice also was compared between bees with and without tracheal mites, and tracheal mite infestation of hosts was compared between bees parasitized or not by varroa during development. The proportion of pollen collectors was not significantly different between treatments, but bees parasitized by both mites had significantly smaller pollen loads than uninfested bees. Mean onset of foraging was earliest for bees parasitized by varroa during development, 15.9 days. Bees with tracheal mites began foraging latest, at 20.5 days, and foraging ages were intermediate in bees with no mites and both, 17.6 and 18.0 days respectively. Phoretic varroa were found equally on bees with and without tracheal mite infestations, but bees parasitized by varroa during development were almost twice as likely to have tracheal mite infestations as bees with no varroa parasitism, 63.9 % and 35.5 %, respectively. These results indicate that these two parasites can have a biological interaction at the level of individual bees that is detrimental to their host colonies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00001697
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  • 20
    Electronic Resource
    Electronic Resource
    Optional gamergates in the queenright ponerine ant Gnamptogenys striatula Mayr (2000)
    Springer
    Insectes sociaux 47 (2000), S. 193-197 
    Details
    ISSN: 1420-9098
    Keywords: Key words: Formicidae, Ponerinae, polygyny, gamergate.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Ponerine ants display a number of social structures to which particular behaviours are associated. In the ponerine ant species Gnamptogenys striatula Mayr, queens occur and queenright colonies are functionally polygynous. However, some workers are capable to mate and to produce their own worker offspring. These gamergates appear several days after the queens are experimentally removed, allowing some workers to adopt a sexual calling posture inside the nest. At that time, other workers get outside the nest to collect males in the arena and carry them back into the colony. There, these males are groomed before they can mate with sexual calling workers. As for queens, several gamergates may coexist in a same colony. The social profile of gamergates is similar to those of nurses and they stay closer to the egg piles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00001701
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  • 21
    Electronic Resource
    Electronic Resource
    Microsatellite analysis of gamergate relatedness of the queenless ponerine ant Rhytidoponera sp. 12 (2000)
    Springer
    Insectes sociaux 47 (2000), S. 188-192 
    Details
    ISSN: 1420-9098
    Keywords: Key words: Queenless ants, relatedness, microsatellites, gamergates, Rhytidoponera sp. 12.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Rhytidoponera sp. 12 is a queenless ponerine ant. Reproduction is only by several to many mated workers (gamergates). Until now there has been no information on the variation in relatedness between colonies of such ants. Here we use data from five highly polymorphic microsatellite markers to determine the intracolony relatednesses of cohabiting gamergates (bgg) collected from five colonies. Contrary to expectations from previous work, cohabiting gamergates are highly related, and colonies were provisionally classified into 2 types based on bgg: Type 1 colonies have full sister gamergates, while in Type 2 colonies gamergates are not full sisters, although still significantly related. The high relatedness observed between nestmate gamergates despite the low relatedness expected on theoretical grounds, the observed low relatedness between unmated nestmates, and the genetic signatures of migration between colonies indicates frequent bottlenecking, such as from colony founding events or catastrophic reductions in the numbers of gamergates per colony.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00001700
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    The effect of nest moisture on daily temperature regime in the nests of Formica polyctena wood ants (2000)
    Springer
    Insectes sociaux 47 (2000), S. 229-235 
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    ISSN: 1420-9098
    Keywords: Key words: Formicidae, thermoregulation, microbial activity, thermal loss, infrared camera.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Relations between nest moisture and daily temperature regime were studied. Two extreme situations were distinguished among the variable patterns of daily temperature regime found. The first one was characterized by increasing temperature during the day and decreasing temperature during the night and was typical for dry nests exposed to sun. The second one was characterized by a lower temperature during the day that increased rapidly during the night. This pattern occurred in moist shaded nests and was less frequent than the first one.¶Patterns of surface nest temperature, which closely correspond with thermal loss, differ between dry and wet nests as well. In dry nests, the temperature decreased during the night on the whole surface in a similar way. In moist nests, the top parts constantly had a high temperature. The average surface temperature during the night was significantly higher in moist than in dry nests, which implies a higher thermal loss in moist nests. Microbial respiration of nest material strongly correlated with nest moisture, which implies a higher microbial heat production in moist nests.¶The results indicated two mechanisms for the maintenance of internal nest temperature. The first one, used in dry nests, is based on a combination of ant metabolic heat production and the isolation properties of a dry nest. The second one, used in moist nests, is based on the metabolic heat production provided by both the ants and the microorganisms in the nest material. These two strategies differ in the pattern of daily temperature fluctuation.
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    URL: http://dx.doi.org/10.1007/PL00001708
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    Antennal glands in queen and worker of the fire ant, Solenopsis invicta Buren: first report in female social Aculeata (Hymenoptera, Formicidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 236-240 
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    ISSN: 1420-9098
    Keywords: Key words: Functional anatomy, imported fire ant, behavioral chemicals, antennal glands, ultrastructure.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The antennae of the higher Hymenoptera (ants, bees and wasps) have been presumed to be exclusively sensory appendages, although the antennae of a number of the Parasitica also support a variety of glands. Using both SEM and TEM we show the presence of ectodermal glands in the antennae of workers and queens, but not in the males, of the Imported Fire Ant, Solenopsis invicta Buren. These glands and their associated pores are present on a glabrous proximal region of A9 of the antennae of workers and both A9 and A10 of queens. The pores leading to the bicellular secretory units in the antennae are more numerous on A10 of the queen followed by A9 of workers and in both cases they form a uniform ring around the segment. However, the pores on A9 of the queen are more numerous on the dorsal surface. While a paste-like secretion can sometimes be seen emerging from the pores of workers, this material is commonly seen from the pores of queen antennae. In social Aculeata, antennal glands have previously been found only in males of some vespids. This report, the first for ants and the first for females of social Aculeata, gives evidence for antennal glands in S. invicta.
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    URL: http://dx.doi.org/10.1007/PL00001709
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    Quantitative and qualitative aspects of trail pheromones in Macrotermes subhyalinus (Isoptera, Termitidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 256-262 
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    ISSN: 1420-9098
    Keywords: Key words:Macrotermes, trail pheromones, exploration, foraging, testing device.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: In the galleries of Macrotermes a differentiated effect of communication was observed, by which the outward running termites could apparently distinguish between going to a feeding place or to virgin ground of exploration. The aim of this study was to investigate trail-activity in the two situations and to find out whether pheromone trails may transmit specific information about the destination of a trail.¶A new device was developed in which running termites could build up their pheromone trails in the context of their natural activity. Such trails were then bio-assayed with another independent group of termites of the same colony, also during their natural activity within an experimentally defined context of behaviour.¶In the described laboratory experiments, it was shown, that termites of Macrotermes subhyalinus, circulating between the nest and an arena filled with soil (situation of exploration), always laid pheromone trails on the substrate. If two channels coming out from the nest led into two identical arenas, an asymmetry of activity was often observed towards the two channels. This asymmetry was also found in the trail bio-assay when comparing the two trails. If one of two paths, however, led to a foraging arena, this path became significantly more active. In this situation the trail bio-assay yielded astonishing results: if the test termites were in the process of exploration, the trail, that previously led to the soil arena, appeared to be significantly more attractive than the foraging trail, even though it was less frequented during the phase before testing. On the other hand, if the test termites were part of a foraging population, the trail which led previously to the food was dominant.¶These results show that pheromone trails in Macrotermes subhyalinus may include both quantitative and qualitative components. The reaction to such information on the trail varies depending on the motivational context of the receivers.
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    URL: http://dx.doi.org/10.1007/PL00001712
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    Male work and sex ratio in social crab spiders (2000)
    Springer
    Insectes sociaux 47 (2000), S. 285-288 
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    ISSN: 1420-9098
    Keywords: Key words: Araneae, Diaea, drone behaviour, nest construction.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Biased sex ratios may alter the contribution that individuals of either sex make to group living. Such a possibility has not been examined in social spiders, in part as adult male spider anatomy and behaviour are focussed on mating. Subadult male behaviour was examined in two congener social crab spiders that have similar ecological niches, Diaea ergandros with an equal sex ratio and D. socialis with a female-biased sex ratio. A laboratory experiment that varied sex ratios of groups of subadults of the two species found that nest construction in D. ergandros did not vary with sex ratio, but that of D. socialis did as males did not contribute to nest construction. This may suggest that among social species, biased sex ratios might influence the appearance of drone-like behaviour.
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    Local enhancement in the wasp Vespula germanica Are visual cues all that matter? (2000)
    Springer
    Insectes sociaux 47 (2000), S. 289-291 
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    ISSN: 1420-9098
    Keywords: Key words: Communication, yellowjackets, local enhancement, social learning.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Local enhancement, a simple process of social transmission, occurs in the wasp Vespula germanica. Past studies have focused on the role played by visual rather than odour cues in attracting conspecific foragers to a food source. However, odour is known to be important in insect communication in general and it has been suggested to influence naive forager wasp choice. In this study, we experimentally studied local enhancement in Vespula germanica, discriminating between odour and visual cues. We show that conspecific odour attracts Vespula germanica foraging workers and that this attraction is comparable to that of an attractive bait. We thus conclude that odour may be playing a central role in local enhancement by this social wasp.
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    Microsatellite analysis suggests occasional worker reproduction in the monogynous ant Crematogaster smithi (2000)
    Springer
    Insectes sociaux 47 (2000), S. 299-301 
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    ISSN: 1420-9098
    Keywords: Key words: Formicidae, worker reproduction, colony structure, microsatellites.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: In addition to a single queen and workers, colonies of the ant Crematogaster smithi from the Chiricahua Mts., Arizona, may contain one or several "large workers". These are specialized for laying viable, unfertilized eggs. However, it is unclear whether in queenright colonies these eggs are all eaten or some of them develop into males. Using microsatellite markers we investigated the genetic structure of colonies of C. smithi. The effective mating frequency of queens is close to one. At least in one of four colonies that contained both a queen and "large workers" and produced males in the laboratory, the genotype of some males suggested worker reproduction.
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    URL: http://dx.doi.org/10.1007/PL00001719
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    Sexual reproduction by both queens and workers in the ponerine ant Harpegnathos saltator (2000)
    Springer
    Insectes sociaux 47 (2000), S. 325-332 
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    ISSN: 1420-9098
    Keywords: Key words: Gamergate, Ponerinae, life history, caste, reproduction, dispersal.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Ant workers are very often reproductively degenerate females, but in some species from subfamily Ponerinae, the workers can mate and lay fertilized eggs just like queens (they are then termed "gamergates"). In Harpegnathos saltator, new colonies are founded independently by single queens, and when senescent they are replaced by several gamergates. This secondary polygyny is distinguished by three features: (1) behavioural data indicate that young workers copulate with their brothers, unlike the queens who disperse and mate outside the nests; (2) gamergate colonies produce both male and female sexuals annually; (3) gamergate colonies appear not to fission. Our evidence for the lack of fission is indirect: the nests of H. saltator are unusually elaborate for ponerine ants, and gamergate colonies produce many young queens (at the expense of investing in workers). Queen supersedure results in an extension of colony lifespan, thus making complex constructions possible with a small colony size (65 ± 40 workers in a western Ghats population; N = 59). In turn, these nests represent a valuable resource to be inherited by successive generations of worker offspring. This life history contrasts with that of other ponerine ants having both queens and gamergates (e.g. in Rhytidoponera confusa, nests are simple and short-lived, gamergates are not inbred and their colonies can fission while producing mostly males; Ward, 1981a, 1983a).
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    Queen mating frequency and relatedness in young Atta sexdens colonies (2000)
    Springer
    Insectes sociaux 47 (2000), S. 354-356 
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    ISSN: 1420-9098
    Keywords: Key words: Ants, Attini, mating frequency, polyandry.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Queen mating frequency is correlated with mature colony size across monogynous ant species as a whole. However, recent comparisons between Atta and Acromyrmex leafcutter ants found an opposite trend. We tested whether this result could be reproduced for Atta sexdens, using a new Atta colombica microsatellite marker to analyse queens and worker offspring from six young colonies. We found that all queens had mated multiply and used sperm from at least 2-3 males. This result is comparable to previous findings for Atta colombica and seems to confirm that queen mating frequency in Atta is lower than in Acromyrmex.
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    URL: http://dx.doi.org/10.1007/PL00001730
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    Amino acid composition of the protein in pre-emergence nests of a paper wasp, Polistes chinensis (Hymenoptera, Vespidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 371-375 
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    ISSN: 1420-9098
    Keywords: Key words: Amino acid composition, oral secretion, nest material, social evolution, Polistes chinensis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Amino acid composition of protein in oral secretion, which is widely used for construction and maintenance of social wasp nests, was analyzed in pre-emergence nests of Polistes chinensis. More than 20 amino acids were detected from field and laboratory nests, among which glycine, serine, alanine, valine and proline were major amino acids in all samples analyzed. The amino acid composition was very similar among various nest parts, and between field and laboratory nests. Foundresses of P. chinensis produce essentially similar kinds of oral secretion despite variation in their nest sites and in the environment around their nests. The composition of P. chinensis is similar to those so far known among other Polistes species, while different in intergenus comparisons. Amino acid composition of protein in oral secretion may reflect phylogenetical relationships among wasps. The chemical nature of oral secretion, especially the presence of proline in its amino acids, as well as the quantity of secretion production may play an important role to harden their nests. Wasps live their social life on nests which are maintained by such secretion characteristics.
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    Polistes dominulus (Hymenoptera, Vespidae) invading North America: some hypotheses for its rapid spread (2000)
    Springer
    Insectes sociaux 47 (2000), S. 155-157 
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    ISSN: 1420-9098
    Keywords: Key words:Polistes, geographic distribution, colonization, adaptability.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Polistes dominulus, a common Polistes species with Old World distribution, is now invading the United States. We discuss those characteristics of P. dominulus that may explain its successful establishment in its new American environment. A versatile diet, the ability to colonize new environments and a short development time of the immature brood might have played an important role in the rapid spread in P. dominulus.
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    Nestmate recognition in the absence of a pheromone (2000)
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    Insectes sociaux 47 (2000), S. 212-219 
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    ISSN: 1420-9098
    Keywords: Key words: Nestmate recognition, Polistes dominulus, pheromones.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Individual recognition cues were manipulated to elucidate the system of nestmate recognition employed by the introduced European paper wasp, Polistes dominulus. Tests involved exposing P. dominulus individuals to their natal nest material, to which we added a novel hydrocarbon, pentacosanoic acid methyl ester, or exposing them to the artificial odor alone. Results show that P. dominulus (1) performs nestmate discrimination, (2) can use artificial exogenous chemicals as recognition odors, and (3) can distinguish single differences in hydrocarbon profiles. Taken individually, these experiments provide evidence revealing the nature of the production and action components of recognition. Taken together, these results establish that recognition takes place outside the classical definition of a pheromone-based system.
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    Queen influence on the shift from trophic to reproductive eggs laid by workers of the ponerine ant Pachycondyla apicalis (2000)
    Springer
    Insectes sociaux 47 (2000), S. 223-228 
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    ISSN: 1420-9098
    Keywords: Key words: Reproductive conflict, oogenesis, trophic eggs, age, queen signalling.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: A single queen reproduces in the colonies of the ponerine ant Pachycondyla apicalis (87 ± 75 workers, n = 85; Fresneau, 1994). Although the castes are only weakly dimorphic, the workers cannot mate and are restricted to producing males. In five queenright colonies, workers laid trophic eggs only and had low levels of ovarian activity. Trophic eggs differ morphologically from reproductive eggs, and are immediately offered to the queen who eats them. In one orphaned colony, a proportion of workers laid reproductive eggs only. Another colony was divided with a double mesh, and after 11 days, workers lacking direct contact with the queen also began to lay reproductive eggs. The age of almost all workers was known in this colony, and their ovarian activity was correlated with age both in the presence and absence of the queen. Our data suggest that the putative queen pheromone is transmitted by close-range contact. The queen walks regularly around the nest, which could be a means of transmitting her signal. Importantly, workers in another two queenright colonies interacted aggressively and laid reproductive eggs, revealing the occasional existence of direct competition for male production between the castes.
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    Carbon dioxide concentrations and nest ventilation in nests of the leaf-cutting ant Atta vollenweideri (2000)
    Springer
    Insectes sociaux 47 (2000), S. 241-248 
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    ISSN: 1420-9098
    Keywords: Key words: Leaf-cutting ants, carbon dioxide, nest ventilation, colony growth, respiration.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Microclimatic conditions in the giant nests of the leaf-cutting ant Atta vollenweideri were experimentally examined to address the question whether increasing concentrations of the respiratory gases affect colony respiration. Measurements of CO2 concentrations of less than 2.8% at different depths inside mature field nests indicated good ventilation, even at 2 m depth. Passive ventilation was driven by wind and promoted by the shape of the nest. It did not influence nest temperature nor relative humidity. During rain and flooding, small colonies closed all nest openings to protect the nest from excessive water influx and damage. Measurements in a small nest indicated that, as a consequence of closure, the Co2 concentration increased rapidly. This situation was simulated in the laboratory, using a small colony of Atta sexdens as a model system. Colony respiration rates were shown to be reduced as a function of increasing CO2 concentration. Based on literature data on ant respiration, it is suggested that the respiration of the symbiotic fungus was reduced, and not that of the ants. Since the brood of leaf-cutting ants feeds exclusively on the fungus, reduced nest ventilation and its effects on respiration rates may compromise colony growth. While mature nests provide the colony with good microclimate under all weather conditions during summer, developing colonies are confronted with a tradeoff between minimizing the risk of inundation and assuring adequate gas exchange inside their nests.
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    Testing genetic variance hypotheses for the evolution of polyandry in the honeybee (Apis mellifera L.) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 271-279 
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    ISSN: 1420-9098
    Keywords: Key words:Apis mellifera, evolution, honeybee, performance, polyandry.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Colony size, honey yields and colony levels of infestation with Varroa jacobsoni of 30 queenright honeybee (Apis mellifera) colonies with naturally mated queens were evaluated over a two-year period. Workers taken from each colony were genotyped at four DNA-microsatellite loci to determine the level of polyandry. All queens mated with more than 10 drones (mean number of observed patrilines = 17.7 ± 5.23). We found significant correlations between colony size and honey yield and between colony sizes of two subsequent years. Analyses of variance revealed a strong impact of the breeding lines on the tested phenotypic traits. The impact of polyandry on colony honey yields was weak (p 〈 0.05, not significant when applying a Bonferroni adjustment) and 8% of the phenotype was determined by the effect of polyandry. The contribution of polyandry to colony size (0.25%) or levels of infestation with Varroa jacobsoni (0.09%) was even weaker in both test years. Likewise, we could not find any averaging effect of polyandry on the honey yield, size nor parasite load of honeybee colonies. Our data set does not resolve the question, whether polyandry and genetic diversity causes more productive colonial phenotypes. If colony level selection is an evolutionary force for polyandry, the effects are hard to detect in man-kept colonies headed by naturally mated queens.
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    Graphing the survivorship of bees (2000)
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    Insectes sociaux 47 (2000), S. 292-296 
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    ISSN: 1420-9098
    Keywords: Key words: Bee survival, hazard rate plotting, increasing hazard rate, survivorship, Weibull distribution.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The statistical distribution of lengths of time (for example, of the survival of bees) is often of interest. This paper describes graphical methods that are appropriate for such data, which typically have a skewed distribution. These methods throw light on the hypothesis of whether hazard rate is constant. Data published by Visscher and Dukas (1997) appear to show increasing hazard rate.
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    Ant nests in tank bromeliads — an example of non-specific interaction (2000)
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    Insectes sociaux 47 (2000), S. 313-316 
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    ISSN: 1420-9098
    Keywords: Key words: Formicidae, Bromeliaceae, Monte Carlo methods, randomisation, commensalism.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Four species of epiphytic tank bromeliads on an island in the Orinoco river in Venezuelan Amazonia were inhabited by 13 ant species from four subfamilies. None of these ant species are known as specialised plant-ants. A Monte Carlo randomisation test showed that ants were randomly distributed among host plants: (1) there was no association between particular ant species and bromeliad species, and (2) there was no vertical stratification of the ant community between bromeliads sampled on the ground and at two height classes in trees. This contrasts with the few published data on the distribution of ants on terrestrial myrmecophytes and epiphytes, respectively, to which we applied the same analytical method.
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    The flow of incoming nectar through a honey bee (Apis mellifera L.) colony as revealed by a protein marker (2000)
    Springer
    Insectes sociaux 47 (2000), S. 302-306 
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    ISSN: 1420-9098
    Keywords: Key words: Honey bees,trophallaxis, nectar storage, communication, marking techniques, ELISA.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The flow of incoming nectar in honeybee (Apis mellifera L.) colonies was simulated by feeding a sucrose solution labeled with a novel protein (rabbit IgG) marker and then analyzing bee and colony samples using an enzyme-linked immunosorbant assay (ELISA). The labeled sucrose solution was quickly transported to food storage and brood combs. Within 2h, equal percentages of worker bees from food storage combs, nurse bees and nectar samples tested positive for the marker. Percentages of nurse bees and larvae testing positive also were equal within the first 2 h of feeding it to a colony and these percentages increased over time. Our results suggest that workers with nectar loads deposit them into cells on either food storage or brood comb with equal frequency. The labeled sucrose solution transported to the brood comb is subsequently used by nurse bees to feed larvae. How the deposition of incoming nectar in brood comb might possibly integrate the activities of foragers and nurse bees is discussed.
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    Worker reproduction in Austroplebeia australis Friese (Hymenoptera, Apidae, Meliponini) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 333-336 
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    ISSN: 1420-9098
    Keywords: Key words:Austroplebeia, worker reproduction, mating, stingless bee, Meliponini.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Two DNA microsatellite markers were used to assess the effective number of mating and the maternity of males in two colonies of Austroplebeia australis (Hymenoptera, Meliponini). In both colonies, the worker genotypes indicated that a single male had inseminated the queens, and the male genotypes indicated that the queens had produced the majority of the males sampled. These results are contrary to the widespread idea that workers would reproduce more readily in monandrous colonies. Possibly, alternative mechanisms such as queen policing, which hinders worker reproduction, might be evolved within this stingless bee taxon.
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    Reproductive strategy in orphaned colonies of Myrmica kotokui Forel, the Japanese species of the M. ruginodis complex (Hymenoptera, Formicidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 343-347 
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    ISSN: 1420-9098
    Keywords: Key words:Monogyny, Myrmica ruginodis complex, orphaned colony, reproductive strategy, worker reproduction.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The reproductive strategy between queen-right and orphaned colonies of Myrmica kotokui was compared. The ratio of orphaned colonies reached about 30 percent in the field. Although colony size was significantly smaller in orphaned colonies, the mean body size and mean ovariole length of the workers were significantly larger than those in queen-right colonies. The reproductive individuals in orphaned colonies were also significantly larger than those in queen-right colonies. Only 38.5 % of the orphaned colonies, however, contained eggs during the reproductive season, compared to 100 % of the queen-right colonies. This indicates that worker reproduction under natural conditions is relatively low, even in orphaned colonies.
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    Thermoregulation of termite mounds: what role does ambient temperature and metabolism of the colony play? (2000)
    Springer
    Insectes sociaux 47 (2000), S. 357-363 
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    ISSN: 1420-9098
    Keywords: Key words: Fungus, Macrotermes bellicosus, Macrotermitinae, metabolism, mound structure.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Termites are well known for their ability to regulate the environment of their nest such as temperature and humidity. The influence of fluctuating ambient temperature and mound characteristics on mean nest temperature and daily fluctuation of nest temperature was analysed quantitatively in the fungus-cultivating, mound-building termite Macrotermes bellicosus (Macrotermitinae) in the savanna of the Comoé National Park (Côte d'Ivoire). Additionally, the nest temperatures of inhabited and uninhabited mounds were compared to analyse the contribution of ambient temperature to nest temperature in relation to metabolic heat production of the termites and their fungi. Mound structure alone resulted in a relatively constant nest temperature. Abiotic heat production via solar radiation alone yielded nest temperatures that corresponded to mean ambient temperatures. However, only the production of metabolic heat by the termites and the fungi increased these temperatures to the actual nest temperature. Therefore, and due to the high heat capacities of the mounds, large colonies (mound height above 2.0 m) had higher nest temperatures than smaller ones. Only large colonies attain constant nest temperatures of 30 °C that are largely independent from ambient temperatures and optimal for the growth and development of the termites and their fungi.
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    Foraging ecology of attine ants in a Neotropical savanna: seasonal use of fungal substrate in the cerrado vegetation of Brazil (2000)
    Springer
    Insectes sociaux 47 (2000), S. 376-382 
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    ISSN: 1420-9098
    Keywords: Key words: Ant-plant interaction, Attini, cerrado vegetation, foraging behavior.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: In this study we identified the material collected as fungal substrate by attine ants in the cerrado vegetation of Southeast Brazil. A total of 313 colonies of the evolutionary more primitive (genera Cyphomyrmex, Mycetarotes, Mycocepurus, Myrmicocrypta) and transitional attines (genera Sericomyrmex and Trachymyrmex) were marked in the field and monitored monthly, during one year. Attines collected material from 53 plant species in 28 families. Items included leaves, flowers, fruits, seeds, wood, mosses, lichens, insect feces and corpses. Flowers and fruits were the items most frequently collected by all genera, especially during the wet season when these plant parts are more abundant in the cerrado. During the dry season, the ants diversified the material collected, and the frequency of different items varied across the ant genera. The most primitive genera collected mainly insect feces and corpses, while the intermediate ones relied on vegetative plant parts such as recently fallen leaflets. Seeds and other materials such as mosses, lichens, and wood were also more commonly used during dry months. The use of these resources was associated with greater foraging distances by all genera in dry months. The results indicate that lower attines present an opportunistic foraging behavior, by collecting items in the vicinity of their nests, and in accordance with the phenology of the cerrado vegetation. We briefly discuss some general evolutionary trends within the Attini.
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    Intracolonial demography of the mound-building termite Macrotermes natalensis (Haviland) (Isoptera, Termitidae) in the northern Kruger National Park, South Africa (2000)
    Springer
    Insectes sociaux 47 (2000), S. 390-397 
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    ISSN: 1420-9098
    Keywords: Key words: Termite colonies, caste composition, Termitida, Macrotermes natalensis, Kruger National Park.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: This paper reports on the number of individuals in Macrotermes natalensis (Hav.) colonies of different sized mounds in the northern Kruger National Park. Mounds were fully excavated, termites collected by means of vacuuming, and colony size estimated by sub-sampling. The proportion of termites in the mound (above and underground sections) amounts to more than 70 % of the colony; the rest being present in the surrounding soil (excavated beyond mound perimeter). It was estimated that, on average, small mounds contain more than 5000, medium mounds more than 45000, and large mounds more than 200000 individual termites. A highly significant relationship between total individuals (N) and mound height (h) was found, given by lnN = 7.893 + 1.093h (r = 0.92). Highly significant correlations (r s 〉 0.90) were found between and within caste numbers, and their respective ratios given. The proportion of soldiers was found to change as colonies grew larger.
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    URL: http://dx.doi.org/10.1007/PL00001736
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    Nestmate interactions and egg-laying behaviour in the queenless ponerine ant Rhytidoponera sp. 12 (2000)
    Springer
    Insectes sociaux 47 (2000), S. 133-140 
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    ISSN: 1420-9098
    Keywords: Key words:Rhytidoponera, ants, gamergate, trophic eggs, nestmate interactions.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Rhytidoponera sp. 12 is a polygynous Australian arid-zone queenless ponerine ant with morphologically identical mated workers (gamergates) and unmated workers. Discriminating gamergates from virgin workers in R. sp. 12 is therefore difficult. All females have functional ovaries and spermatheca. The ability of unmated workers to lay trophic eggs has not been reported. In four R. sp. 12 colonies we found that gamergates have tough reddish-brown cuticle differing from that of the dark brown unmated workers. Gamergates were successfully identified by combining this observable morphological difference with previously described behavioural traits thus eliminating the need of identification through dissection. In a laboratory-kept colony gamergates showed mutual tolerance. Egg-shuffling behaviour by gamergates was observed. A high proportion of unmated workers laid trophic eggs that were either cannibalised or shared between nestmates; larvae were observed to feed exclusively on these trophic eggs. Eggs laid by gamergates were sometimes eaten, although the majority of these were deposited onto egg piles carried by unmated workers. Oophagy of viable eggs by gamergates may represent a form of dominance behaviour or, together with egg-shuffling, a behaviour to resist manipulation by less fecund gamergates. Removing gamergates from three colonies led to oocyte development in some unmated workers, indicating that ovarian development in virgin workers may be reduced in the presence of gamergates.
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    Morpho-physiological variability and differentiation of reproductive roles among foundresses of the primitively eusocial wasp, Belonogaster petiolata (Degeer) (Hymenoptera, Vespidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 147-154 
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    ISSN: 1420-9098
    Keywords: Key words:Polistinae, social wasps, dominance hierarchy, reproductive capacity, body size.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Pre-nesting foundresses of Belonogaster petiolata (Degeer) displayed a continuous variation in body size and ovarian development, wherein the majority (96%) of females possessed well-developed or developing ovaries. The latter indicates that most foundresses, including those that ultimately become subordinates in multiple-foundress colonies, have the potential to lay eggs when they first initiate or join nests. Relatively small differences in ovarian development between associated females at the start of the nesting season became pronounced over the course of the pre-emergence and early pre-matrifilial period concurrently with the differentiation of their roles as queens or subordinates. In pre-matrifilial colonies, ovarian development of queens was significantly greater than that of subordinates. Dominance rank and ovarian development among subordinates in pre-matrifilial colonies were not correlated, probably due to advanced ovarian regression in these females. The majority (96.5%) of foundresses from three successive nesting seasons were inseminated and would therefore have been capable of laying female-producing (i.e. worker- and queen-destined) eggs. Although queens of B. petiolata were not significantly larger than subordinates, they were the largest females in 41% of colonies. Similarly, β-foundresses were larger on average than γ-foundresses. This indicates that body size may contribute to social and reproductive dominance, but is probably of secondary importance compared with hormonal and nutritional factors. These and previously published findings from B. petiolata suggest that the fitness benefits of associating with other foundresses during colony foundation may be largely mutualistic, and favoured by individual selection in addition to kin selection.
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    Individual and colony factors in bumble bee division of labor (Bombus bifarius nearcticus Handl; Hymenoptera, Apidae) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 164-170 
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    ISSN: 1420-9098
    Keywords: Key words: Brood care, colony age, demography, foraging, polyethism, thermoregulation.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: We quantified the relationships of colony-level factors (number of workers and colony age) with task performance by workers of the bumble bee Bombus bifarius. Worker's age of first foraging decreased as their colonies aged, which may have caused the observed decrease in worker longevity with colony age. Daily variation in colony nectar foraging rates was related to the number of active foragers, while pollen foraging rates corresponded more strongly with variation in numbers of adult workers. Rates of brood care behavior decreased as the colonies aged, but rates of thermoregulatory behavior (incubation and fanning) did not decrease over time. We conclude that rates of performing some tasks (pollen foraging, brood care) were largely determined by changes in colony demography or correlated variables, while rates of performance of other tasks (nectar foraging, thermoregulation) depended more on external environmental conditions. Most workers switched between two foraging tasks (pollen and nectar collection) and among several in-nest tasks. However, some foragers specialized by focusing their effort on either nectar or pollen. Other workers specialized on in-nest tasks by performing thermoregulatory behavior (incubation and fanning) at significantly higher rates than their nestmates. The task specialists contributed disproportionate amounts of labor to their colonies. Task specialization indicates that workers were not identical in their responses to variation in colony need.
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    The influence of pollen storage area and Varroa jacobsoni Oudemans parasitism on temporal caste structure in honey bees (Apis mellifera L.) (2000)
    Springer
    Insectes sociaux 47 (2000), S. 177-182 
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    ISSN: 1420-9098
    Keywords: Key words:Varroa jacobsoni, pollen, honey bees, Apis mellifera, temporal polyethism.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The influence of colony pollen storage and pupal infestation by the parasitic mite Varroa jacobsoni on worker longevity, foraging age, and behavior were investigated in the honey bee, Apis mellifera L. Workers reared in colonies with low pollen stores began foraging at younger ages and may have had shorter lifespans than workers reared in colonies with high pollen availability. Similarly, workers began foraging at younger ages and had shorter lifespans when they had been infested by V. jacobsoni as pupae. The decrease in foraging age and possibly lifespan caused by the pupal infestation was offset by the colony's pollen environment during brood rearing. Therefore, temporal task schedules are affected by both colony investment and parasitism by V. jacobsoni during brood rearing.
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    The artificial insemination of bumblebee queens (2000)
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    Insectes sociaux 47 (2000), S. 183-187 
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    ISSN: 1420-9098
    Keywords: Key words: Artificial insemination, Bombus, bumblebee breeding, multiple mating.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Artificial insemination (AI) is a technique to transfer instrumentally sperm from the male into the female's reproductive system. AI is widespread in vertebrates for economical animal breeding and for conservation biology. However, in invertebrates only a few cases of successful AI have been reported. In this paper we describe a new technique to artificially inseminate bumblebee queens (Bombus spp.). Males were dissected and the accessory testes were removed and washed in insect ringer. They were then opened and the outflowing sperm was picked up with a glass capillary mounted on a syringe. For the sperm transfer into the queen we adapted a standard apparatus used for honeybee inseminations. The queen was anaesthetized with CO2, held in place by a queen holder and the sting chamber was opened using two hooks. The sperm containing glass capillary was introduced into the queen's sexual tract. The sperm was released into the bursa copulatrix very near the opening of the spermathecal duct of the queen. Inseminated queens were hibernated for 2 weeks and produced a normal colony under field conditions. Multiple inseminations proved to be successful since different patrilines could be detected in the worker offspring. Successful inseminations were performed for B. terrestris, B. lucorum and B. hypnorum.
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    Task partitioning in insect societies: novel situations (2000)
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    Insectes sociaux 47 (2000), S. 198-199 
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    ISSN: 1420-9098
    Keywords: Key words: Task partitioning, excavation, emigration, refuse disposal.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Ratnieks and Anderson (1999) recently reviewed task partitioning in insect societies. They collated numerous examples of partitioned tasks involving the collection and transportation of colony resources to the nest. However, no non-foraging examples were known. Here we report task partitioning in excavation, emigration, and refuse disposal. We also report an example of task partitioning without strong division of labour.
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    Effect of leaf toughness on the susceptibility of the leaf-cutting ant Atta sexdens to attacks of a phorid parasitoid (2000)
    Springer
    Insectes sociaux 47 (2000), S. 220-222 
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    ISSN: 1420-9098
    Keywords: Key words: Atta sexdens, leaf-cutting ants, Neodohrniphora, parasitism, Phoridae.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Because the size of Atta spp. along foraging trails is partly determined by the characteristics of the plants harvested, and considering that parasitic phorid flies are attracted mostly to large individuals, we hypothesized that plant toughness affects the susceptibility of Atta spp. to these parasitoids. To test this hypothesis, we evaluated parasitism rates of the phorid Neodohrniphora sp. and its effect on Atta sexdens (L.) foragers in a laboratory colony. We manipulated forager size by alternating tough (Anthocephalus chinensis, Rubiaceae) and tender (Rosa chinensis, Rosaceae) plants given to the colony. Ants foraging on tough leaves were larger than ants foraging on soft leaves, and there was a significant reduction in forager size for both plants when the colony was exposed to Neodohrniphora sp. However, there were no relative differences on forager size between the two plants after the introduction of the parasitoid. The lack of response of Neodohrniphora sp. to the increase in ant size when the colony was given tough leaves may be attributed to the unusually large number of suitable hosts in a laboratory colony. However, large foragers are much less abundant in the field, in which case shifts in the size of the workforce triggered by different substrates could affect the incidence of parasitism.
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    Colony size and reproduction in the western harvester ant, Pogonomyrmex occidentalis (2000)
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    Insectes sociaux 47 (2000), S. 249-255 
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    ISSN: 1420-9098
    Keywords: Key words: Reproduction, size-based demography, size thresholds, mating flights, Pogonomyrmex.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: We report data from a four-year field study on the relationship between colony size and reproduction in the western harvester ant, Pogonomyrmex occidentalis. In all years, the likelihood of reproduction significantly increased with increasing size in both field censuses during naturally-occurring mating flights and experimentally-watered colonies whose entire reproductive output was collected. However, the total amount of reproductive biomass was unrelated to colony size. We describe the size threshold for reproduction in P. occidentalis and show that it varies across years. Once colonies become reproductively mature, they reproduce consistently although not in every year. We describe a method for collecting the entire reproductive output for desert ants whose reproductive flights are cued by rainfall.
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    Queen polymorphism in the Australian ant Monomorium sp.10 (2000)
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    Insectes sociaux 47 (2000), S. 280-284 
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    ISSN: 1420-9098
    Keywords: Key words: Queen polymorphism, wing reduction, dispersal, Monomorium.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The Australian ant Monomorium sp.10 exhibits a queen polymorphism with initially winged gynomorphs and wingless intermorphs. Female sexuals eclosing from brood produced by a gynomorphic queen are always winged, whereas offspring of intermorphic queens consists of both winged and wingless female sexuals. The exchange of brood between colonies suggests that queen morph is determined either genetically or by a maternal effect. We discuss the occurrence of genetically based queen polymorphism in ants and its ecological significance.
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    Population-typical behaviours are retained when eusocial and non-eusocial forms of Evylaeus albipes (F.) (Hymenoptera, Halictidae) are reared simultaneously in the laboratory (2000)
    Springer
    Insectes sociaux 47 (2000), S. 263-270 
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    ISSN: 1420-9098
    Keywords: Key words: Eusocial, photoperiod, temperature, behavioural phenotypes, social evolution, Halictidae.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: We compare the behaviour of daughters of Evylaeus albipes females from eusocial populations from the West of France with those from a non-eusocial population from the East of the country. When non-eusocial population females are placed in the laboratory under day lengths and temperature conditions similar to those experienced by eusocial foundresses under natural conditions, all five produced a brood of males and overwintering daughters with no workers. When 18 nests were initiated by non-eusocial foundresses under short summer daylengths but warmer than normal temperatures, two produced one worker amongst overwintering female and male brood. Both worker-producing non-eusocial females were from the warmest of the eastern localities. When foundresses of the social population are placed under day length conditions typical for the non-eusocial population but with temperature conditions that are intermediate between the two, all five produced at least one worker. Similarly, if the first brood produced by social foundresses is removed, they raise another brood that contains workers whereas non-eusocial population foundresses who have their first brood removed produce a second brood of overwintering females (although one foundress, again from the warmest of the non-eusocial localities, produced one worker in each of two broods, also with males and overwintering females). We conclude that i) non-eusocial foundresses do not readily produce workers under long summer conditions; ii) the lack of worker production by most non-eusocial population females is not because they cannot produce two broods, but because they have a tendency not to produce workers; iii) eusocial population daughters will become active without diapausing in the presence of any other female - even of the closely related E. calceatus, unless the first individual to eclose is the smallest and iv) social population foundresses are incapable of producing overwintering females without the help of workers. These data show an interesting combination of flexibility and constraint on social behaviour in these bees.
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    Associations of mutillid wasps (Hymenoptera, Mutillidae) with eusocial insects (2000)
    Springer
    Insectes sociaux 47 (2000), S. 201-211 
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    ISSN: 1420-9098
    Keywords: Key words: Apis, Bombus, Chrysomelidae, Formicidae, Halictinae, parasitoids.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The larvae of mutillid wasps are parasitoids of insect host stages which are not actively feeding and are enclosed in some sort of package (cell, cocoon, puparium). The literature dealing with mutillids living in association with eusocial insects is surveyed and evaluated, and some new host records are provided. Relatively few mutillid species are involved despite the potential for prolific reproduction on social hosts. The problems faced by such parasitoids are greater than those encountered when using solitary hosts. Several species of mutillids parasitise social halictine bees, a few parasitise bumble bees and a few occasionally attack honey bees; a few are parasitoids of commensals or symbionts of ants. Their possible occurrence in the nests of other eusocial insects is briefly discussed.
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    Technique for rearing the European hornet (Vespa crabro) through an entire colony life cycle in captivity (2000)
    Springer
    Insectes sociaux 47 (2000), S. 351-353 
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    ISSN: 1420-9098
    Keywords: Key words:Hornets, mating, nest initiation, overwintering, Vespa crabro.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Laboratory rearing of wasps was studied in the European hornet Vespa crabro. Males (N = 10) and gynes (N = 13) were obtained from two field-caught colonies. Mating took place in cages (mean number of 1.31 ± 0.63 matings per gyne) and overwintering in a cool room at 10 °C. Five gynes survived and one queen successfully established a nest that produced sexuals. This is first time that the entire colony life cycle of V. crabro has occurred in captivity. The technique will be useful in vespine research as well as in conservation and breeding programs.
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    Do environmental conditions exert an effect on nest-mate recognition in queen rearing honey bees? (2000)
    Springer
    Insectes sociaux 47 (2000), S. 307-312 
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    ISSN: 1420-9098
    Keywords: Key words: Honey bees, nest-mate recognition, kinship, queen rearing.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Most studies of discrimination in the context of queen rearing have been performed in spring or summer, but the influence of environmental conditions on nepotism in honeybees has not received attention. Our experiments were designed to test the hypothesis that restricted resources influence honeybee workers to express a bias towards rearing related larvae more strongly than under favorable conditions. Three experimental designs were employed. In the first experiment, larvae were grafted using standard commercial techniques for rearing queens. Nurse bees were presented with sister larvae and alien larvae placed each in a cup, side by side in alternating positions. In the second experiment, nurse bees were offered the choice between sister or alien larvae placed in the same cup. The third experiment was similar to the first except that the objective was to harvest and weigh the accepted larvae and the remaining royal jelly. This study demonstrates that our colonies did not display nepotism in the context of queen rearing, whatever the season.
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    Humidity preference for fungus culturing by workers of the leaf-cutting ant Atta sexdens rubropilosa (2000)
    Springer
    Insectes sociaux 47 (2000), S. 348-350 
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    ISSN: 1420-9098
    Keywords: Key words:Leaf-cutting ant, humidity, fungus culturing, nest climate, choice.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: The hygropreference of gardening workers of the leaf-cutting ant Atta sexdens rubropilosa was investigated in the laboratory using a gradient of relative humidity. Gardening workers were placed, together with pieces of fungus garden, in small, interconnected nest chambers offering four different relative humidities: 33 %, 75 %, 84 % and 98 % RH. Workers were allowed to move freely between them and to relocate the fungus following their humidity preference. While workers distributed themselves randomly in the nest chambers, they located the fungus gardens in the chamber with the highest humidity. These results indicate that gardening workers are able to sense differences in relative humidity, and that this ability is shown when they are engaged in fungus culturing. Humidity is discussed as one of the relevant variables that probably underlay the evolution of regulatory responses for the control of fungus growth in leaf-cutting ants.
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    How to study subterranean army ants: a novel method for locating and monitoring field populations of the South East Asian army ant Dorylus (Dichthadia) laevigatus Smith, 1857 (Formicidae, Dorylinae) with observations on their ecology (2000)
    Springer
    Insectes sociaux 47 (2000), S. 317-324 
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    ISSN: 1420-9098
    Keywords: Key words: Army ants, hypogaeic, Dorylinae, novel method.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: A new method employing palm oil as bait was developed for studying the distribution and ecology of subterranean army ants. In SE Asia the hypogaeic army ant Dorylus laevigatus was found to be very common in both forested and open environments. More than 10000 workers were found at individual baits. The workers cooperatively dig a three-dimensional tunnel network into the soil. Over a period of 72 days no emigrations of D. laevigatus could be detected, a first indication of a facultatively stationary way of life in this ant. Encounters with Pheidologeton silenus about food resources were observed. In feeding experiments D. laevigatus readily took a variety of arthropods and annelids but ignored starch containing vegetables as food. The rare hypogaeic D. (Alaopone) cf. vishnui could be collected for the first time in India and Sri Lanka. Also the epigaeic D. (Anomma) nigricans from Africa were found to be attracted to palm oil. The oil-method thus provides the opportunity to detect and monitor populations of army ants of the genus Dorylus in tropical and subtropical habitats.
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    Evolution of extreme polyandry: an estimate of mating frequency in two African honeybee subspecies, Apis mellifera monticola and A.m. scutellata (2000)
    Springer
    Insectes sociaux 47 (2000), S. 364-370 
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    ISSN: 1420-9098
    Keywords: Key words: Polyandry, Apis mellifera subspecies, population genetics, microsatellite loci.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Mating frequencies in two related honeybee subspecies Apis mellifera monticola and A. m. scutellata were compared using a set of five microsatellite loci in order to discriminate among the major factors which have affected the evolution of extreme polyandry. We found that the queens of eight A.m. monticola colonies collected from an apiary in Malawi, mated 5-19 times producing an average relatedness among workers of 0.328 ± 0.049. The six A.m. scutellata colonies collected from an apiary in South Africa displayed a significantly larger degree of polyandry, i.e. queens mated 10-25 times and the genetic relatedness among nestmates was 0.283 ± 0.020. The difference in the degree of polyandry observed between the populations suggests that socially based selective pressures are not of primary importance in the evolution of extreme polyandry but that ecological selective pressures play a more significant role. However, exploring the relative contributions of these factors to the variation in levels of polyandry will require the use of colonies in which the level of polyandry is experimentally controlled.
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    Worker size polymorphism and ethological role of sting associated glands in the harvester ant Messor barbarus (2000)
    Springer
    Insectes sociaux 47 (2000), S. 383-389 
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    ISSN: 1420-9098
    Keywords: Key words: Size polymorphism, exocrine glands, defence, trail, harvester ants.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary: Though harvester ants are closely similar in ecology, species differ in their worker size polymorphism as well as in the glandular source of their trail pheromones and defensive compounds. In the harvester ant Messor barbarus, we find that the recruitment trail pheromone is located in the Dufour gland, while defence-alarm substances are produced in the poison gland. We also investigated how the glandular development and the ethological response to these abdominal glands are related to worker body size. For both glands, M. barbarus workers show monophasic and nonisometric growths with slopes of allometric regression lines lower than 1. The highest trail-following response is elicited by the Dufour gland secretion from media workers, responsible for most foraging activities in M. barbarus. Aggressive behaviour is more frequently observed in the presence of poison gland secretions from medium and large-sized workers. Differences between species and between worker size classes in the ethological role of sting associated glands are discussed in relation to the foraging ecology and defensive characteristics of harvester ants.
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    A Study of Chloride Aerosol, Total Aerosol and Ice Nuclei in the Indian Regions (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1541-1556 
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    ISSN: 1420-9136
    Keywords: Key Words: Chloride aerosol, total aerosol, ice nuclei, millipore filter, maritime, continental, semi-arid.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —Atmospheric aerosols were sampled from aircraft at various levels over Rihand in northern India during the monsoon season of 1974 and at surface levels at Calcutta, Delhi, Varanasi and Jodhpur during different seasons of 1970 and 1971. Millipore filter assembly was used for this purpose. Chloride nuclei, total aerosol and ice nuclei concentrations were evaluated from millipore filters. At Rihand/Varanasi, during the monsoon, the chloride size spectrum was broader and the distribution bimodal at cloud base level while the spectra were narrower and the distributions unimodal at other levels. At Rihand, chloride mass and larger giant chloride number were considerably higher, total aerosol higher while ice nuclei concentrations were lower on the days with moderate rain as compared to those with light rain. Calcutta (maritime) showed maximum while Varanasi (well-inland) showed minimum chloride number concentrations. As compared with Calcutta, Delhi (continental) had lower chloride and total aerosol, and markedly higher ice nuclei concentrations. Varanasi (high rainfall region) showed all the values, except for small-sized chlorides, notably higher with respect to Jodhpur (low rainfall region). Ice nuclei concentration was lowest in winter and highest in summer at Delhi. Variations of the aerosols during different parts of the day/night are also discussed.
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    URL: http://dx.doi.org/10.1007/PL00001132
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    Microtremors as a Geophysical Exploration Tool: Applications and Limitations (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1445-1462 
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    ISSN: 1420-9136
    Keywords: Key Words: Frequency of resonance, geophysical exploration, H/V ratios, microtremors, soil thickness.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —The usefulness of microtremors as a geophysical exploration tool has been analyzed. This application is possible due to the relationship between the main resonance frequency of a given soil, obtained from the H/V spectral ratios of microtremors, its thickness and average shear velocity. We first measured the ambient noise at 33 sites and determined their main resonance frequency. Detailed geotechnical information was available for 23 of the sites, thereby allowing us to establish a quantitative relationship between the resonance frequency and the thickness of the soil, and indirectly between either of them and the shear velocity of the soil. The practical application of this relationship has revealed its usefulness in determining the surface structure of a valley with excellent accuracy, with an error of only 15% in the depths calculated. These errors are due to the simplification of the problem that this method implies: it requires that the shear velocity vary constantly with depth throughout the study region, which is evidently not always so, and that the input data themselves intrinsically have a certain degree of uncertainty. This method is therefore not valid when there is no mechanical contrast between the study soil and the underlying layer or when the shear velocity varies irregularly with depth in the study area.
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    URL: http://dx.doi.org/10.1007/PL00001128
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    Relative Seismic Quiescence Before Large Aftershocks (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1407-1421 
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    ISSN: 1420-9136
    Keywords: Key Words: Aftershocks, prediction, quiescence, Greece.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —In terms of the modified Omori’s formula and Akaike’s Information Criterion, thirteen aftershock sequences have been analysed quantitatively, to check if any anomalous change of seismic activity took place before the occurrence of the largest aftershock. The analysis follows the method proposed by . The epicentre distribution of the main shocks covers the Aegean Sea (Greece) area and the surrounding regions. The earthquakes occurred from 1988 to 1998.¶Although difficulties existed for a quantitative treatment of seismic quiescence, the results of the temporal analysis of the aftershock activities seem to be promising. In eight of thirteen cases the observed temporal pattern is similar. The aftershock activity decreases significantly before the occurrence of the largest aftershock, with respect to the level expected according to the modified Omori’s formula. Thereafter, the activity recovers to its previous level just before or immediately after the occurrence of the main aftershock. Moreover, an estimation of the reliability of the method is made, based on the results of this study as well as of previous similar investigations. From a total of 41 aftershock sequences which have been analysed following Matsu’ura’s method, 29 of them (71%) show a remarkable relative quiescence before the occurrence of the main shock.¶Although it is difficult to construct a model which explains the precursory pattern, the real time monitoring and check for seismic quiescence could at least contribute to a ‘qualitative’ prediction of the largest aftershock which could at times be as large and disastrous as the main shock.
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    URL: http://dx.doi.org/10.1007/PL00001126
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    Characteristics of Cloud Drop Spectra at Different Levels and with Respect to Cloud Thickness (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1557-1569 
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    ISSN: 1420-9136
    Keywords: Key Words: Cloud drop size spectrum, higher and lower levels, cloud thickness, liquid water content, drop concentrations, mean volume diameter, dispersion, unimodal, bimodal.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —Measurements on drop size spectra were made in cumulus clouds over Pune (inland) region on many days during the summer monsoon seasons. In this paper, the measurements in non-raining cumulus clouds made in the years 1984, 1985 and 1986 at different levels and for different cloud thickness have been studied. In general, the drop size spectra broadened with height and the concentration of drops with diameter 〉 50 μm (N L ), mean volume diameter (MVD), liquid water content (LWC) and dispersion increased with height while the concentration of drops with diameter 〈 20 μm (N S ) and the total concentration of drops (N T ) decreased with height. The average drop size distributions were unimodal at the lower levels while they were bimodal at the higher levels. High water contents were confined to drops in the size range 5–25 μm at both higher and lower levels. The average drop size spectra were broader and N L , LWC, MVD and dispersion greater while N T and N S smaller for thicker clouds (range of vertical extent 1.1–2.1 km) as compared to those for thinner clouds (range of vertical extent 0.3–1.1 km). Water contents for the drops 〉 28 μm were higher while those for the drops 〉 28 μm lower in thicker clouds than in thinner clouds. The average drop size distributions were bimodal in the former case, while they were unimodal in the other case.
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    URL: http://dx.doi.org/10.1007/PL00001133
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    Localized Denoising Filtering Using the Wavelet Transform (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1463-1491 
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    ISSN: 1420-9136
    Keywords: Key Words: Threshold, denoising, filtering, wavelet, multiresolution, potential field.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —Gravity and magnetic signals are usually affected by noise, which is in turn related either to the geological heterogeneity of the shallow structures or to the measurement and data processing procedures. Along the map, the signal is represented by field anomalies which overlap with the noise in a variable and complicated way. Classical filtering techniques such as the Fourier (band-pass) filtering or the wavelet “cycle-spinning” method denoise the data only in a global sense and are therefore inaccurate when the frequency content of the signal is no longer uniform. We propose instead a localized denoising of such data, based on localized filtering techniques using the wavelet transform. The localized denoising filtering is based on a “soft thresholding” rule and is characterized by a local thresholding parameter (LTP). An adaptive tuning of the LTP parameter allows enhancement of the high frequencies of the signal and is effective to remove the noise as much as possible. The method is confronted using two different kinds of wavelets, namely the biorthogonal and the multiscale shiftable transforms and is applied to the noisy vertical derivative of the gravity field of Sicily. The technique proves to be superior to classical methods and may be similarly applied to any manner of geophysical data.
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    URL: http://dx.doi.org/10.1007/PL00001129
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    Fractal Geometry of Faults and Seismicity of Koyna-Warna Region West India Using LANDSAT Images (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1393-1405 
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    ISSN: 1420-9136
    Keywords: Key Words: Fractal dimension, faults, Koyna-Warna, seismotectonic, earthquakes.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —The Koyna-Warna region has been shaken by several earthquakes greater than magnitude 4 in the last 35 years. Four of them in 1967, 1973, 1980 and 1993, were potentially very destructive with magnitudes exceeding 5.0. The majority of seismic events recorded to date has been induced from Koyna-Warna reservoir areas. This paper discusses the fractal analysis of a fault map from LANDSAT images with the increasing seismic activity in the region. The region is divided into six blocks and the fractal dimension of each block is calculated using a box-counting technique. A plot of a three-dimensional map of the fractal dimension is prepared. It shows that the value of the fractal dimension is gently dipping from NE to SW. The fractal dimension is used to estimate the b-value in the frequency-magnitude relation of earthquakes in the region which is in agreement with earlier studies.
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    URL: http://dx.doi.org/10.1007/PL00001125
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    Groundwater Ion Content Precursors of Strong Earthquakes in Kamchatka (Russia) (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1359-1377 
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    ISSN: 1420-9136
    Keywords: Key Words: Precursors, earthquakes, groundwater, ions, Kamchatka.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —The Kamchatka peninsula, located in the far east of Russia, is a geologically active margin where the Pacific plate subducts beneath the North American and Eurasia plates. This area is characterised by frequent and strong seismic activity (magnitudes reaching 8.6) and epicentres are generally distributed offshore along the eastern coast of the peninsula. For many years, hydrogeochemicals have been sampled with a mean interval of three days to measure the most common ions in the groundwater of five deep wells in the southern area of the Kamchatka peninsula. In the last decade, five earthquakes with M 〉 6.5 have occurred at distances less than 250 km from these wells. These earthquakes were powerful enough for them to be considered as potential originators of precursors. In order to reveal possible precursors of these earthquakes, we analysed the groundwater ion contents. The quasi-periodic annual variation was filtered out, together with other slow trends, and then we smoothed out the high frequency fluctuations that arise from errors in a single measurement. When examining the data, we labelled each signal with an amplitude greater than three times the standard deviation as an irregularity and we made a first attempt at defining an anomaly as an irregularity occurring simultaneously in more than one parameter at each well. In a second definition we used the existence of an irregularity occurring simultaneously in each ion at more than one well. Then, on the basis of past results worldwide and the time interval between the earthquakes observed, we chose 158 days as the maximum temporal window between a possible anomaly and the subsequent earthquake. With the first anomaly definition we identified 6 anomalies with 4 possible successes and 2 failures. For the five earthquakes considered capable of producing precursors we obtained precursors in three cases. With the second anomaly definition we identified 10 anomalies with 7 possible successes and 3 failures and we obtained precursors in four of the five earthquakes. A schematic model explaining aspects of the complex relationship linking earthquakes and ion content anomalies is also presented.
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    URL: http://dx.doi.org/10.1007/PL00001123
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    Seismic Zoning of Slovenia Based on Deterministic Hazard Computations (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 171-184 
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    ISSN: 1420-9136
    Keywords: Key Words: Seismic hazard, seismic zoning, Slovenia.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract. Seismic hazard of the territory of Slovenia is estimated using a deterministic approach based on the computation of complete synthetic seismograms. The input data are the catalogues of earthquakes and fault plane solutions for Slovenia and surrounding regions. Structural models are defined based on available seismological and geophysical information, but are mainly constrained by surface-wave dispersion and 3-D tomographic modelling of the upper crust. Seismogenic zones are delineated considering geotectonic characteristics, fault plane solutions and distribution of earthquake hypocentres. Outside Slovenia seismogenic zones are extended up to distances from which they can considerably influence seismic hazard estimates.¶Synthetic seismograms are computed using the “receiver” structure along the entire path by normal mode summation (up to 1 Hz) for receiver sites on a 0.2 × 0.2 degrees grid and scaled to the magnitude of the earthquake allowing for spectral falloff. At each site the maximum value of horizontal velocity, horizontal displacement and design ground acceleration are considered as hazard parameter. The highest values are obtained for western Slovenia where the hazard is controlled by the strongest earthquake in the catalogue, the “Idrija” event of March 26, 1511.
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    URL: http://dx.doi.org/10.1007/PL00001093
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    Dynamic Propagation and Interaction of a Rupture Front on a Planar Fault (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1959-1979 
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    ISSN: 1420-9136
    Keywords: Key Words: Dynamic earthquake rupture, rupture front interaction, boundary integral equation method.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstrac —We investigate the propagation and interaction of a rupture front that propagates on a planar fault using a boundary integral equation method. We show first that the rupture velocity is controlled by a delicate balance between consumed fracture energy and supplied elastic strain energy. A very sharp boundary in parameter space separates models in which ruptures stop spontaneously from those in which rupture propagates at super-shear speeds. The transition zone (or bifurcation) is shown to be stable with reference to small-scale heterogeneities of the stress field. Using the relations derived from this analysis we examined the mechanism to generate high slip rate when two rupture fronts collide. We found that collision at slow rupture velocities causes abrupt stress drop and generates high slip rates. However, these features tend to be moderated by large slip-weakening distances. Finally, we simulated rupture front focusing at the initial stages of an earthquake, a phenomenon that may cause high slip rate pulses and therefore generate high frequency seismic waves. We assume a pre-slip region, in which stress has decreased quasi-statically to the dynamic friction level. Due to this pre-slip, strong stress concentration has developed around the pre-slip area and a dynamic rupture starts at a certain point on the rim of the pre-slip region. We observe rupture front focusing that generates high slip rate pulses. We also studied a double pre-slip model, in which two pre-slip regions exist close to each other before the earthquake and found that multiple pre-slips enhance the focusing effects.
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    URL: http://dx.doi.org/10.1007/PL00001070
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    Accelerating Seismic Energy Release and Evolution of Event Time and Size Statistics: Results from Two Heterogeneous Cellular Automaton Models (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 2209-2226 
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    ISSN: 1420-9136
    Keywords: Key Words: Accelerating seismic energy, heterogeneous cellular automaton, self-organized criticality, critical point hypothesis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —The evolution of event time and size statistics in two heterogeneous cellular automaton models of earthquake behavior are studied and compared to the evolution of these quantities during observed periods of accelerating seismic energy release prior to large earthquakes. The two automata have different nearest neighbor laws, one of which produces self-organized critical (SOC) behavior (PSD model) and the other which produces quasi-periodic large events (crack model). In the PSD model periods of accelerating energy release before large events are rare. In the crack model, many large events are preceded by periods of accelerating energy release. When compared to randomized event catalogs, accelerating energy release before large events occurs more often than random in the crack model but less often than random in the PSD model; it is easier to tell the crack and PSD model results apart from each other than to tell either model apart from a random catalog. The evolution of event sizes during the accelerating energy release sequences in all models is compared to that of observed sequences. The accelerating energy release sequences in the crack model consist of an increase in the rate of events of all sizes, consistent with observations from a small number of natural cases, however inconsistent with a larger number of cases in which there is an increase in the rate of only moderate-sized events. On average, no increase in the rate of events of any size is seen before large events in the PSD model.
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    URL: http://dx.doi.org/10.1007/PL00001081
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    The Plausibility of Long-wavelength Stress Correlation or Stress Magnitude as a Mechanism for Precursory Seismicity: Results from Two Simple Elastic Models (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 2227-2248 
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    ISSN: 1420-9136
    Keywords: Key Words: Precursory seismicity, stress correlation.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —Observations of accelerating seismic activity prior to large earthquakes in natural fault systems have raised hopes for intermediate-term earthquake forecasting. If this phenomena does exist, then what causes it to occur? Recent theoretical work suggests that the accelerating seismic release sequence is a symptom of increasing long-wavelength stress correlation in the fault region. A more traditional explanation, based on Reid's elastic rebound theory, argues that an accelerating sequence of seismic energy release could be a consequence of increasing stress in a fault system whose stress moment release is dominated by large events. Both of these theories are examined using two discrete models of seismicity: a Burridge-Knopoff block-slider model and an elastic continuum based model. Both models display an accelerating release of seismic energy prior to large simulated earthquakes. In both models there is a correlation between the rate of seismic energy release with the total root-mean-squared stress and the level of long-wavelength stress correlation. Furthermore, both models exhibit a systematic increase in the number of large events at high stress and high long-wavelength stress correlation levels. These results suggest that either explanation is plausible for the accelerating moment release in the models examined. A statistical model based on the Burridge-Knopoff block-slider is constructed which indicates that stress alone is sufficient to produce accelerating release of seismic energy with time prior to a large earthquake.
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    URL: http://dx.doi.org/10.1007/PL00001082
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    Generalised Seismic Hazard Maps for the Pannonian Basin Using Probabilistic Methods (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 147-169 
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    ISSN: 1420-9136
    Keywords: Key Words: Seismic hazard maps, Pannonian Basin, Monte Carlo simulation, Vrancea, intermediate focus earthquakes, seismic hazard methodology.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —A set of seismic hazard maps, expressed as horizontal peak ground acceleration, is presented for a large area of Central Eastern Europe, covering the Pannonian Basin and surrounding area. These maps are based on (a) a compound earthquake catalogue for the region; (b) a seismic source model of 50 zones compiled on the basis of tectonic divisions and seismicity, and (c) a probabilistic methodology using stochastic (Monte Carlo) modelling. It is found that the highest hazard in the region derives from intermediate focus earthquakes occurring in the Vrancea seismic zone; here the hazard exceeds 0.4 g at return periods of 475 years. Special account has been taken of the directional nature of attenuation from this source. The maps are intended for use in studies of comparative methodologies for seismic hazard assessment.
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    A Contribution to Seismic Hazard Assessment in Croatia from Deterministic Modeling (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 185-204 
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    ISSN: 1420-9136
    Keywords: Key Words: Seismic hazard, deterministic modeling, synthetic seismograms, Croatia.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —Some of the elements of regional seismic hazard in Croatia are assessed by computing synthetic accelerograms at a predetermined set of sites. The input dataset consists of structural models, parameters of seismic sources, and an updated earthquake catalog. Synthetic strong-motion time series for frequencies below 1 Hz are computed on a grid of sites using the modal summation technique. The long-period hazard is described by the distribution of estimated peak values of ground displacement, velocity and acceleration, while the short-period hazard is represented by the map of design ground acceleration values (DGA). The highest values of DGA exceeding 0.35 g on the base-rock level are found in the southeastern coastal part of the country, in the greater Dubrovnik area.
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    Book Reviews (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1803-1816 
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    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
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    URL: http://dx.doi.org/10.1007/s000240050009
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    A Method to Remove Electromagnetic Coupling from Induced Polarization Data for an “Exponential” Earth Model (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1729-1748 
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    ISSN: 1420-9136
    Keywords: Key Words: Induced polarization, electromagnetic coupling, exponential variation of resistivity, mineral exploration, Turkey.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —The electromagnetic (EM) coupling effect in induced polarization (IP) data is an important problem. In many works it has been computed only considering homogeneous or layered earth models with discretely uniform conductivity. In this study, an algorithm has been developed to compute the EM coupling effect in IP data measured on the earth, whose conductivity varies (increases or decreases) exponentially with depth. The EM coupling effects for Percent Frequency Effect (PFE) and phase data are computed for a dipole-dipole array with different separations, however the method can be applied to any electrode array. The results obtained for the cases of increasing and decreasing conductivity as a function of depth indicate that the EM coupling effect strongly depends on the subsurface resistivity and the dipole length. Here an “exponential” earth model is considered to remove EM coupling from the IP data in frequency and phase domain. For this purpose, first, the region of pseudo-section is divided into segments, and within each segment a typical average apparent resistivity (ρ a) curve is constructed. An exponential conductivity model is fitted to average ρ a data. The conductivity model is then used to compute EM responses. Next the data are corrected for the EM coupling contribution. This decoupling process is applied to field data from a galenite-pyrite mineralization area at the Dolluk site, in western Turkey. The results from the decoupling method developed here are compared with other techniques.
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    Nonlinear Structural Subsystem of GeoFEM for Fault Zone Analysis (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 2105-2124 
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    ISSN: 1420-9136
    Keywords: Key Words: Fault zone, contact problem, augmented Lagrange method, iterative solver, GeoFEM.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstrac —GeoFEM (Iizuka et al., 1999) is a parallel finite element analysis system intended for multi-physics, multi-scale problems of solid earth field phenomena. Very large linear elastic problems have already been resolved by parallel computation with GeoFEM. The next stage is to examine large-scale nonlinear problems using GeoFEM. The analysis of large-scale contact problems for fault zones is particularly important in the development of models that simulate the occurrence and cycle of earthquakes.¶This paper proposes a parallel FEM using an iterative solver with the augmented Lagrange method for solving large-scale contact problems. Direct solvers are presently applied to contact problem analysis because the matrix for such problems is ill-conditioned. However, direct solvers are not suitable for large-scale matrices. The augmented Lagrange method can improve the matrix conditions. The present study evaluates a parallel FEM using an iterative solver with the augmented Lagrange method. Analysis of a contact problem with the augmented Lagrange method revealed that an optimal penalty parameter exists and that large-scale parallel contact analysis using the iterative solver with localized preconditioning is promising.
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    URL: http://dx.doi.org/10.1007/PL00001077
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    Continuous GPS Array and Present-day Crustal Deformation of Japan (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 2303-2322 
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    ISSN: 1420-9136
    Keywords: Key Words: GPS, crustal deformation, the Japanese islands, data assimilation.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —A GPS array with about 1,000 permanent stations is under operation in Japan. The GPS array revealed coseismic deformations associated with large earthquakes and ongoing secular deformation in the Japanese islands. Based on daily coordinate data of the GPS stations, strain rate distribution is estimated. Most regions with a large strain rate are related to plate boundaries and active volcanoes. In addition, the Niigata-Kobe Tectonic Zone (NKTZ) is recognized as a region of large strain rate along the Japan Sea coast and in the northern Chubu and Kinki districts. This newly found tectonic zone may be related to a hypothetical boundary between the Eurasian (or Amurian) and the Okhotsk (or North America) plates. Precise observation of crustal deformation provides important boundary conditions on numerical modeling of earthquakes and other crustal activities. Appropriate computation methods of continuous deformation field are directly applicable to data assimilation for such numerical simulations.
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    Implications of a Statistical Physics Approach for Earthquake Hazard Assessment and Forecasting (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 2323-2349 
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    ISSN: 1420-9136
    Keywords: Key Words: Earthquake hazard assessment, self-organized critical behavior, inverse-cascade model, spinoidal behavior.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —There is accumulating evidence that distributed seismicity is a problem in statistical physics. Seismicity is taken to be a type example of self-organized criticality. This association has important implications regarding earthquake hazard assessment and forecasting. A characteristic of a thermodynamic system is that it exhibits a background noise that is self-organized. In the case of a dilute gas, this self-organization is the Maxwell–Boltzmann distribution of molecular velocities. In seismicity, it is the Gutenberg–Richter frequency-magnitude scaling; this scaling is fractal. Observations favor the hypothesis that smaller earthquakes in moderate-sized regions occur at rates that are only weakly dependent on time. Thus, the rate of occurrence of smaller earthquakes can be extrapolated to assess the hazard of larger earthquakes in a region. We obtain the rate of occurrence of earthquakes with m 〉 4 in 1°× 1° areas from the NEIC catalog. Using only this data we produce global maps of the seismic hazard. Observations also favor the hypothesis that the stress level at which an earthquake occurs is a second-order critical point. As a critical point is approached, correlations extend over increasingly larger distances. In terms of seismicity, the approach to a critical point is associated with an increase in the rate of occurrence of intermediate-sized earthquakes prior to a large earthquake. This precursory activation has been shown to exhibit power-law scaling and to occur over a region about ten times larger than the rupture length of the large earthquake. Analyses of the spinoidal behavior associated with second-order critical points predict the power-law increase in seismic activity prior to a characteristic earthquake. This precursory activation provides the basis for intermediate-range earthquake forecasting.
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    About the Efficiency of Numerical 1-D and 2-D Modelling of Site Effects in Basin Structures (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 319-342 
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    ISSN: 1420-9136
    Keywords: Key Words: Site effects, seismic hazard analysis, numerical 1-D and 2-D modelling, reflectivity method, Aki-Larner method, finite difference modelling.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —In the present study we compare results obtained from experimental estimates of local site amplification effects with those from numerical modelling using four different techniques. We benefit from an extremely precise knowledge of the near-surface structure and experimental estimates of the local amplification factors which are determined from seismic weak-motion data recorded by a dense array across a sedimentary basin at a European test-site in Northern Greece. The possibilities and limitations of the different modelling techniques (a 1-D technique, and three 2-D techniques) to model the effects of local amplification effects are tested. Amplifications calculated by the numerical techniques are only qualitatively compared with observed data from experimental studies in the time domain and directly in the frequency domain.¶As a result we conclude that, in the case of a complex subsurface geometry, 1-D modelling underestimates the amplification patterns in terms of absolute amplification level, and cannot correctly account for resonant frequencies, at least for modes higher than the fundamental mode. If a more realistic incident wave field than just a plane wave is taken into account, 2-D modelling reveals the fundamental frequency and shows adequate amplifications not only at the fundamental frequency but also at higher frequencies. The general trend of the amplifications at the lowest frequencies is well determined by the 2-D numerical modelling, and can therefore supply information for seismic risk analysis.
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    URL: http://dx.doi.org/10.1007/s000240050002
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    Groundwater, Radon Continuous Monitoring System (α-scintillation Counting) for Natural Hazard Surveillance (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 407-433 
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    ISSN: 1420-9136
    Keywords: Key Words: Continuous radon monitor prototype, review of methods, seismic, volcanic and environmental surveillance.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —A “quasi continuous mode” monitoring system to measure the radon concentration within a natural environment (mainly groundwater), was designed, assembled and tested, under collaboration between DINCE and ING, partly within the framework of two EC funded programs.¶The radon monitor consists of a customised discrete automatic sampler which produces a gas flux circuit, and an economical α-scintillation cell, coupled with a reliable electronics-photomultiplier assemblage. A convenient calibration system together with a temporised control system have been set up. The overall “mean efficiency” of the system was calculated to be 7.79±0.13 counts per minute (cpm) for each Bq/L.¶Taking into consideration the present and future requirements of a geochemical surveillance network to assess natural hazards, the prototype design evolved from the study of existing systems devoted to monitor radon concentration levels, which are critically reviewed within this paper.¶In response to the main prerequisite of a remote station: maximum remote sensor versatility preserving shared software and hardware for the network as a whole, this radon monitoring system was conceived as part of a multi-parametric Geochemical Monitoring System (GMS II) prototype, designed and realised as a test-stand for sensors (chemical, hydrological, geophysical, organic chemistry devoted, etc.) in continuous evolution throughout the international market.
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    Book Reviews (2000)
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    Pure and applied geophysics 157 (2000), S. 469-484 
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    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
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    Fractal Approach of Structuring by Fragmentation (2000)
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    Pure and applied geophysics 157 (2000), S. 539-557 
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    ISSN: 1420-9136
    Keywords: Key Words: Rock fragmentation, crack patterns, fractal distributions, geodynamics.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —The paper addresses the problem of fingerprints of fragmentation processes, showing that structuring by fragmentation can be detected and investigated fruitfully if approached with a proper methodology, of which fractal instruments represent an important part. Studied aspects include fragments size distributions, fragments size-position relations, and long-range correlations in fracture profiles and fracture patterns. The choice of experiments (comminution of flat samples and fragmentation by desiccation cracking) was directed by the aim to complement existing studies from the point of view of fragmentation energy application, being also intended to provide data from processes where different mechanisms are at work. Power-law fragments size distributions were found, but also fragments clusters on dominant size intervals that point towards a fractal character of the size distribution from the point of view of the positions of the distribution maxima. The self-affine character of fractures and of fracture patterns could be emphasised on certain scale intervals, separated by thresholds that are important for studies concerning the implied mechanisms. Fragments size-position correlations indicate a high probability of neighbouring fragments to be of comparable size. The features highlighted for structuring by fragmentation were found in all the studied experiments, their generality pointing towards useful implications for geoscientific research.
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    Micromorphic Continuum and Fractal Fracturing in the Lithosphere (2000)
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    Pure and applied geophysics 157 (2000), S. 559-574 
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    ISSN: 1420-9136
    Keywords: Key Words: Micromorphic continuum, rotational wave, faults, earthquakes, fractals.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —It seems that internal structures and discontinuities in the lithosphere essentially influence the lithospheric deformation such as faulting or earthquakes. The micromorphic continuum provides a good framework to study the continuum with microstructure, such as earthquake structures. Here we briefly introduce the relation between the theory of micromorphic continuum and the rotational effects related to the internal microstructure in epicenter zones. Thereafter the equilibrium equation, in terms of the displacements (the Navier equation) in the medium with microstructure, is derived from the theory of the micromorphic continuum. This equation is the generalization of the Laplace equation in terms of displacements and can lead to Laplace equations such as the local diffusion-like conservation equations for strains. These local balance/stationary state of strains under the steady non-equilibrium strain flux through the plate boundaries bear the scale-invariant properties of fracturing in the lithospheric plate with microstructure.
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    Variation of Permeability with Porosity in Sandstone Diagenesis Interpreted with a Fractal Pore Space Model (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 603-619 
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    ISSN: 1420-9136
    Keywords: Key Words: Permeability, sandstone, fractals, diagenesis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —Permeability is one of the key rock properties for the management of hydrocarbon and geothermal reservoirs as well as for aquifers. The fundamental equation for estimating permeability is the Kozeny-Carman equation. It is based on a capillary bundle model and relates permeability to porosity, tortuosity and an effective hydraulic pore radius which is defined by this equation. Whereas in clean sands the effective pore radius can be replaced by the specific surface or by the grain radius in a simple way, the resulting equations for permeability cannot be applied to consolidated rocks. Based on a fractal model for porous media, equations were therefore developed which adjust the measure of the specific surface and of the grain radius to the resolution length appropriate for the hydraulic process. These equations are calibrated by a large data set for permeability, formation factor, and porosity determined on sedimentary rocks. This fractal model yields tortuosity and effective pore radius as functions of porosity as well as a general permeability-porosity relationship, the coefficients of which are characteristic for different rock types. It can be applied to interpret the diagenetic evolution of the pore space of sedimentary rocks due to mechanical and chemical compaction with respect to porosity and permeability.
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    The Hulopoe Gravel, Lanai, Hawaii: New Sedimentological Data and their Bearing on the “Giant Wave” (Mega-Tsunami) Emplacement Hypothesis (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1257-1284 
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    ISSN: 1420-9136
    Keywords: Key Words: Gravel, facies analysis, coastal sedimentation, rocky shoreline, ocean island, Hawaii, tsunami, submarine landslide.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —Recognition that many oceanic islands are shaped by giant landslides has highlighted claims that the Hulopoe Gravel on south Lanai, Hawaii, was deposited by giant waves (mega-tsunami) generated by such a landslide. This interpretation is controversial. Resolution of the controversy has global implications because mass wasting of oceanic islands has been a common process for as long as hot spot volcanism has affected the ocean basins. Thus, if mega-tsunami are attendant upon the mass wasting process, their effect on earth surface processes should be discernible for much of geological time and may be comparable to that resulting from bolide impacts that form astroblemes.¶Detailed facies analysis of the pebble, cobble and boulder gravels that form the Hulopoe Gravel type section shows that the gravels are composed predominantly of basalt clasts with appreciable amounts of limestone clasts in 8 of the 14 beds present. Deposition was not continuous: eight disconformities are recognized in the 9.2 m type section, three of which are associated with truncated paleosols. The Hulopoe Gravel was not deposited by a single tsunami at 105 ka, as has been proposed. One bed is clearly an alluvial deposit. The origins of others are unclear but the facies data do not exclude tsunami as one of the processes that deposited individual beds within the Hulopoe Gravel, either above or below sea level.
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    Applying Probability Determination to Refine Landslide-triggering Rainfall Thresholds Using an Empirical “Antecedent Daily Rainfall Model” (2000)
    Springer
    Pure and applied geophysics 157 (2000), S. 1059-1079 
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    ISSN: 1420-9136
    Keywords: Key Words: Landslides, probabilistic threshold determination, rainfall threshold, critical water content.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —Rainfall-triggered landslides constitute a serious hazard and an important geomorphic process in many parts of the world. Attempts have been made at various scales in a number of countries to investigate triggering conditions in order to identify patterns in behaviour and, ultimately, to define or calculate landslide-triggering rainfall thresholds. This study was carried out in three landslide-prone regions in the North Island of New Zealand. Regional landslide-triggering rainfall thresholds were calculated using an empirical “Antecedent Daily Rainfall Model.” In this model, first introduced by, triggering rainfall conditions are represented by a combination of rainfall occurring in a period before the event (antecedent rainfall) and rainfall on the day of the event. A physically-based decay coefficient is derived for each region from the recessional behaviour of storm hydrographs and is used to produce an index for antecedent rainfall. Statistical techniques are employed to obtain the thresholds which best separate the rainfall conditions associated with landslide occurrence from those of non-occurrence or a given probability of occurrence.The resultant regional models are able to represent the probability of occurrence of landsliding events on the basis of rainfall conditions. The calculated thresholds show regional differences in susceptibility of a given landscape to landslide-triggering rainfall. These differences relate to both the landslide database and the difference of existing physical conditions between the regions.
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    Isolated Singularity for the Stationary Navier—Stokes System (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 151-184 
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    ISSN: 1422-6952
    Keywords: Keywords. The stationary Navier—Stokes system, homogeneous harmonic polynomials, power series expansion and isolated singularity.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract. In this paper the classical method to prove a removable singularity theorem for harmonic functions near an isolated singular point is extended to solutions to the stationary Stokes and Navier—Stokes system. Finding series expansion of solutions in terms of homogeneous harmonic polynomials, we establish some known results and new theorems concerning the behavior of solutions near an isolated singular point. In particular, we prove that if (u, p) is a solution to the Navier—Stokes system in $ B_R \setminus \{0\} $ , $ n \geq 3 $ and $ |u(x)| = o\,(|x|^{-(n - 1)/2}) $ as $ |x| \to 0 $ or $ u \in L^{2n/(n - 1)}(B_R) $ , then (u, p) is a distribution solution and if in addition, $ u \in L^{\beta}(B_R) $ for some $ \beta 〉 n $ then ( u, p) is smooth in B R .
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    A Sufficient Condition on the Pressure for the Regularity of Weak Solutions to the Navier—Stokes Equations (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 99-106 
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    ISSN: 1422-6952
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract. It is well known that a weak solution (v, p) to the Navier-Stokes equations is regular if v satisfies some suitable extra conditions (see (1.2), (1.3)). However, with the exception of the recent papers [BV4], [BV5] (see also [K], [Be]) not so much attention has been payed to “alternative natural assumptions” that p may fulfill, in order that (v, p) be regular. By “alternative natural assumptions”, we mean assumptions that formally follow from the Poisson equation relating pressure and velocity (see (1.4)). The objective of this paper is to prove that (v, p) is regular if $ |p|/(1 + |v|) $ obeys some conditions that are in formal agreement with this relation.
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    On the Smoothness of a Class of Weak Solutions to the Navier—Stokes equations (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 315-323 
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    ISSN: 1422-6952
    Keywords: Keywords. Navier—Stokes equations, regularity, projection.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract. We improve regularity criteria for weak solutions to the Navier-Stokes equations stated in references [1], [3] and [12], by using in the proof given in [3], a new idea introduced by H. O. Bae and H. J. Choe in [1]. This idea allows us, in one of the main hypothesis (see eq. (1.7)), to replace the velocity u by its projection $ \bar u $ into an arbitrary hyperplane of $ {\Bbb R}^n $ ; see Theorem A. For simplicity, we state our results for space dimension $ n \le 4 $ , since if $ n \ge 5 $ the proofs become more technical and additional hypotheses are needed. However, for the interested reader, we will present the formal calculations for arbitrary dimension n.
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    Unstable Eigenvalues Associated with Inviscid Fluid Flows (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 365-380 
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    ISSN: 1422-6952
    Keywords: Keywords. Euler equation, inviscid flow, instability, method of averaging.
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    Topics: Mathematics , Physics
    Notes: Abstract. An example is presented of a class of periodic, two-dimensional, inviscid fluid flows where the stability spectrum contains both discrete unstable eigenvalues and an unstable essential spectrum. The method of averaging is used to demonstrate the existence of unstable eigenvalues. For such flows spectral instability implies nonlinear instability.
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    On the Singular Incompressible Limit of Inviscid Compressible Fluids (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 107-125 
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    ISSN: 1422-6952
    Keywords: Keywords. Inviscid compressible flows, singular limits, incompressible Euler equations, boundary value problems.
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    Notes: Abstract. We consider the Euler equations of barotropic inviscid compressible fluids in a bounded domain. It is well known that, as the Mach number goes to zero, the compressible flows approximate the solution of the equations of motion of inviscid, incompressible fluids. In this paper we discuss, for the boundary case, the different kinds of convergence under various assumptions on the data, in particular the weak convergence in the case of uniformly bounded initial data and the strong convergence in the norm of the data space.
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    Global Existence of Weak Solutions for Viscous Incompressible Flows around a Moving Rigid Body in Three Dimensions (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 219-266 
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    ISSN: 1422-6952
    Keywords: Keywords. Navier—Stokes equations, rigid body motions.
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    Notes: Abstract. We study the motion of a rigid body of arbitrary shape immersed in a viscous incompressible fluid in a bounded, three-dimensional domain. The motion of the rigid body is caused by the action of given forces exerted on the fluid and on the rigid body. For this problem, we prove the global existence of weak solutions.
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    Steady Flows of Viscoelastic Fluids in Domains with Outlets to Infinity (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 185-218 
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    ISSN: 1422-6952
    Keywords: Keywords. Viscoelastic fluids, weighted function spaces, outlets to infinity, asymptotic behaviour, secondary flows.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract. The equations governing the motion of incompressible viscoelastic fluids of Rivlin—Ericksen and Oldroyd type are investigated in domains with cylindrical and paraboloidal outlets to infinity. For sufficiently small fluxes, prescribed in each outlet, existence and uniqueness of solutions are proven in weighted Hölder spaces. In domains with paraboloidal outlets the solution is obtained as a perturbation of the corresponding Navier—Stokes solution and in domains with cylindrical outlets as a perturbation of a flux carrier, constructed by joining together the exact solutions found in each outlet. These exact solutions are shown to be either rectilinear flows of Poiseuille type or flows composed of a rectilinear and of a transverse secondary component.
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    On the Asymptotic Behavior of Physically Reasonable Solutions to the Stationary Navier—Stokes System in Three-dimensional Exterior Domains with Zero Velocity at Infinity (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 353-364 
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    ISSN: 1422-6952
    Keywords: Keywords. Navier—Stokes system, 3D exterior domains, physically reasonable solutions, asymptotic behavior.
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    Notes: Abstract. We consider physically reasonable solutions of the stationary Navier—Stokes system in a three-dimensional exterior domains with zero velocity at infinity. We show that when these solutions are asymptotically expanded near infinity, the leading term cannot be the product of a non-zero vector with the Stokes fundamental solution. This result should be contrasted with the case when the velocity at infinity is not zero. Then, as is well known, such an expansion is possible, with the leading term being the product of a suitable constant vector with the fundamental Oseen solution.
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    On the Strong Solvability of the Navier—Stokes Equations (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 16-98 
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    ISSN: 1422-6952
    Keywords: Keywords. Weak, very weak, and strong solutions; existence and uniqueness theorems with rough initial data.
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    Topics: Mathematics , Physics
    Notes: Abstract. In this paper we study the strong solvability of the Navier—Stokes equations for rough initial data. We prove that there exists essentially only one maximal strong solution and that various concepts of generalized solutions coincide. We also apply our results to Leray—Hopf weak solutions to get improvements over some known uniqueness and smoothness theorems. We deal with rather general domains including, in particular, those having compact boundaries.
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    Multimodels for Incompressible Flows (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 126-150 
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    ISSN: 1422-6952
    Keywords: Keywords. Navier—Stokes equations, domain decomposition methods, finite elements, spectral element methods, far-field boundary treatment.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract. The Navier—Stokes equations for incompressible fluids are coupled to models of reduced complexity, such as Oseen and Stokes, and the corresponding transmission conditions are investigated. A mathematical analysis of the corresponding problems is carried out. Numerical results obtained by finite elements and spectral elements are shown on several flow fields of physical interest.
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    Weak Solutions for a Class of Non-Newtonian Fluids with Energy Transfer (2000)
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    Journal of mathematical fluid mechanics 2 (2000), S. 267-293 
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    ISSN: 1422-6952
    Keywords: Keywords. Non-Newtonian fluids, energy transfer, variational inequality, weak solutions.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract. In the present paper, we shall consider a nonlinear thermoconvection problem consisting of a coupled system of nonlinear partial differential equations due to temperature dependent coefficients. We prove that weak solutions exist in appropriate Sobolev spaces under mild hypothesis on the regularity of the data. This result is established through a fixed point theorem for multivalued functions, which requires a detailed analysis of the continuous dependence of auxiliary problems, including the associated Lagrange multipliers of the generalized Navier—Stokes system.
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    Named Organic Reactions. By Thomas Laue and Andreas Plagens, John Wiley & Sons: Chichester, England, New York, 1998. Structural formulas, reaction schemes. x + 288 pp. 15.6 x 23.5 cm. $69.95, hardcover. ISBN 0–471–97142–1 (2000)
    Springer
    The chemical educator 5 (2000), S. 96-97 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1007/s00897990374a
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    The Best of Annals of Imporabable Research (AIR). Edited by Marc Abrahams. W. H. Freeman: New York, 1998. Illustrations. vii + 208 pp. 21.5 cm. $14.95. Softcover. ISBN 0–7167–3094–4 (2000)
    Springer
    The chemical educator 5 (2000), S. 99-101 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
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    NMR Verification of Diastereoselective Reduction of Substituted Cyclohexanones (2000)
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    The chemical educator 5 (2000), S. 64-66 
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    ISSN: 1430-4171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This experiment provides an ideal opportunity to integrate NMR spectroscopy, stereochemical principles, and the use of enzymes in the sophomore-level organic chemistry laboratory. Students work in teams and reduce either 2-methylcyclohexanone or 4-tert-butylcyclohexanone using common baker’s yeast (Saccharomyces Cerevisiae) and sodium borohydride. The stereochemistry and diastereomeric ratios of alcohols produced are determined using proton NMR. The students are asked to rationalize the contrast in stereoselectivity observed with the different reducing agents. This experiment has an advantage over other baker’s yeast reduction experiments [1–4] in that the diastereoselectivity can be directly determined by NMR.
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