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  • Springer  (115,674)
  • 2020-2020
  • 2005-2009  (48,764)
  • 1995-1999  (66,910)
  • 2009  (48,764)
  • 1999  (66,910)
Collection
Years
  • 2020-2020
  • 2005-2009  (48,764)
  • 1995-1999  (66,910)
Year
  • 1
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    Unknown
    Springer
    Publication Date: 2020-02-12
    Type: info:eu-repo/semantics/book
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  • 2
    Publication Date: 2020-11-17
    Description: An efficient procedure is proposed in order to define realistic lower limits of velocity errors of a non-permanent GPS station (NPS), i.e. a station where the antenna is installed and operates for short time periods, typically 10-20 days per year. Moreover, the proposed method is aimed at being independent from the standard GPS data processing. The key is to appropriately subsample the coordinate time series of several continuous GPS stations (CGPSs) situated nearby or inside the considered NPS network, in order to simulate the NPS behavior and to estimate the velocity errors associated with the subsampling procedure. The obtained data are therefore used as lower limits to accept or correct the error estimates provided by standard data processing. The proposed approach is applied to data from the dense non-permanent network in the Central Apennine of Italy based on a sequence of solutions for the overlapping time spans 1999-2003, 1999-2004, 1999-2005 and 1999-2007. Both the original and error-corrected velocity patterns are used to compute the strain rate fields. The comparison between the corresponding results reveals large differences that could lead to divergent interpretations about the kinematics of the study area.
    Description: Published
    Description: 249–261
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Non-permanent GPS Stations ; Velocity Field ; Strain Rate ; Survey Optimization; ; Solution Sequence ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2020-12-23
    Description: In July 1998, an Mw = 6.2 earthquake struck the islands of Faial, Pico and San Jorge (in the Azores Archipelago), registering VIII on the Modified Mercalli Intensity scale and causing major destruction in the northeastern part of Faial. The main shock was located offshore, 8 km North East of the island, and it triggered a seismic sequence that lasted for several weeks. The existing data for this earthquake include both the general tectonic environment of the region and the teleseismic information. This is accompanied by one strong-motion record obtained 15 km from the epicentre, the epicentre location of aftershocks, and a large collection of the damage inflicted to the building stock (as poor rubble masonry, of 2-3 storeys). The present study was carried out in two steps: first, with a finite-fault stochastic simulation method of ground motion at sites throughout the affected islands, for two possible locations of the rupturing fault and for a large number of combinations of rupture mechanisms (as a parametric analysis); secondly, the damage to buildings was modelled using a well-known macroseismic method that considers the building typologies and their associated vulnerabilities. The main intent was to integrate different data (geological, seismological and building features) to produce a scenario model to reproduce and justify the level of damage generated during the Faial earthquake. Finally, through validation of the results provided by these different approaches, we obtained a complete procedure for the parameters of a first model for the production of seismic damage scenarios for the Azores Islands region.
    Description: Published
    Description: 361–381
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Description: open
    Keywords: Stochastic finite-fault scenarios ; Building damage assessment ; 9th July Faial earthquake ; Azores Islands ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2021-07-13
    Description: The aim of this study was to investigate the microbial community thriving at two shallow hydrothermal vents off Panarea Island (Italy). Physico-chemical characteristics of thermal waters were examined in order to establish the effect of the vents on biodiversity of both Bacteria and Archaea. Water and adjacent sediment samples were collected at different times from two vents, characterised by different depth and temperature, and analysed to evaluate total microbial abundances, sulphuroxidising and thermophilic aerobic bacteria. Total microbial abundances were on average of the order of 105 cells ml-1, expressed as picoplanktonic size fraction. Picophytoplanktonic cells accounted for 0.77–3.83% of the total picoplanktonic cells. The contribution of bacterial and archaeal taxa to prokaryotic community diversity was investigated by PCR–DGGE fingerprinting method. The number of bands derived from bacterial DNA was highest in the DGGE profiles of water sample from the warmest and deepest site (site 2). In contrast, archaeal richness was highest in the water of the coldest and shallowest site (site 1). Sulphur-oxidising bacteria were detected by both culture- dependent and -independent methods. The primary production at the shallow hydrothermal system of Panarea is supported by a complex microbial community composed by phototrophs and chemolithotrophs.
    Description: Published
    Description: 199-212
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: hydrothermal vents ; bacteria ; geochemistry ; fluids ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
    Publication Date: 2020-11-16
    Description: Geological, geophysical and geotechnical investigations, for the characterization of the strong-motion recording sitesmanaged by the ItalianCivil Protection, have been carried out in the framework of the project “Italian strong-motion database in the period 1972–2004”. The project aimed at creating an updated database of strong-motion data acquired in Italy by different institutions in the time span 1972–2004, and at improving the quality of disseminated data. This article illustrates the state of the recording site characterization before the beginning of the project, explains the criteria adopted to select the sites where geophysical/ geotechnical investigation have been performed and describes the results of the promoted field surveys.
    Description: Published
    Description: 1189–1207
    Description: 4IT. Banche dati
    Description: JCR Journal
    Description: open
    Keywords: site ; characterization ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
    Publication Date: 2017-04-04
    Description: The objective of the COST296 Action MIERS (Mitigation of Ionospheric Effects on Radio Systems) is to develop an increased knowledge of the effects imposed by the ionosphere on practical radio systems, and for the development and implementation of techniques to mitigate the deleterious effects of the ionosphere on such systems (http://www.cost296.rl.ac.uk). The COST296 Community contributes to the international efforts of IHY with scientific and outreach activities as well. After the realization of a web site hosted by Istituto Nazionale di Geofisica e Vulcanologia (INGV), developed also to promote the ionospheric physics to the open public, the COST296 Community supported an initiative addressed to the pupils of the primary school of several European Countries: the realization of a school-calendar dedicated to the Sun and to the Sun-Earth connections.
    Description: Published
    Description: 63-67
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: 5.9. Formazione e informazione
    Description: JCR Journal
    Description: reserved
    Keywords: E/PO ; Space weather ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.07. Space and Planetary sciences::05.07.01. Solar-terrestrial interaction
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
    Publication Date: 2017-04-04
    Description: The complex geochemical interactions in the groundwater of the industrial area of S ˇ alek Valley (Slovenia) between natural and anthropogenic fluids were studied by means of major (Ca, Mg, Na, K, HCO3 -, Cl- and SO4 2-) and trace elements’ (As , Cd, Cu, Pb, Zn, Hg, Se and V) abundances, geochemical classification and statistical analysis of data. Cation abundances indicate mixing between a dolomitic end-member and an evaporitic or geothermal end-member. Anion abundances indicate mixing between bicarbonate waters and either sulphateenriched waters (suggesting hydrothermalism) or chlorinerich waters. Principal component analysis (PCA) allowed the extraction of seven factors, which describe, respectively: water–rock interaction mainly on dolomitic rocks; redox conditions of water; Cd–Zn enrichment in chlorinerich waters (probably from industrial wastes); hydrothermal conditions in waters close to major faults; Pb and Cu pollution; V and K enrichments, indicating their common organic source; the role of partial pressure of CO2 dissolved in water, which is highest in three wells with bubbling gases. Average underground discharge rates of solutes from the Valley range between 0.09 t/a (V) and 1.8 9 104 t/a (HCO3 -) and indicate how natural fluids can significantly contribute to the levels of elements in the environment, in addition to the amount of elements released by human activities.
    Description: Ministry of Foreign Affairs of Italy and Ministry of Superior Instruction, Science and Technology of Slovenia. Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo
    Description: Published
    Description: 75-89
    Description: 4.4. Scenari e mitigazione del rischio ambientale
    Description: JCR Journal
    Description: reserved
    Keywords: groundwater ; Slovenia ; geothermal systems ; Principal Component Analysis ; pollution ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
    Publication Date: 2017-04-04
    Description: The Italian strong-motion database was created during a joint project between Istituto Nazionale di Geofisica e Vulcanologia (INGV, Italian Institute for Geophysics and Vulcanology) and Dipartimento della Protezione Civile (DPC, Italian Civil Protection). The aim of the project was the collection, homogenization and distribution of strong motion data acquired in Italy in the period 1972-2004 by different institutions, namely Ente Nazionale per l’Energia Elettrica (ENEL, Italian electricity company), Ente per le Nuove tecnologie, l’Energia e l’Ambiente (ENEA, Italian energy and environment organization) and DPC. Recently the strong-motion data relative to the 23th December 2009, Parma (Mw=5.4 and Mw=4.9) and to the 2009 L’Aquila sequence (13 earthquakes with 4.1Mw6.3) were included in the ITACA database (beta release). The database contains 7038 waveforms from analog and digital instruments, generated by 1019 earthquakes with magnitude up to 6.9 and can be accessed on-line at the web site http://itaca.mi.ingv.it. The strong motion data are provided in the unprocessed and processed versions. This article describes the steps followed to process the acceleration time series recorded by analogue and digital instruments. The procedures implemented involve: baseline removal, instrumental correction, band pass filtering with acausal filters, integration of the corrected acceleration in order to obtain velocity and displacement waveforms, computation of acceleration response spectra and strong motion parameters. This procedure is applied to each accelerogram, is realised to preserve the low frequency content of the records.
    Description: In press
    Description: 5.2. TTC - Banche dati di sismologia strumentale
    Description: JCR Journal
    Description: open
    Keywords: strong-motion ; processing ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2017-04-04
    Description: In the Rocca Busambra area (mid-west Sicily, Italy), from November 1999 to July 2002, 23 water points including wells and springs were sampled and studied for their chemical and isotopic compositions. Two rain gauges were also installed at different altitudes, and rainwater was collected monthly to determine the isotopic composition. The obtained results revealed the Rocca Busambra carbonate complex as being the main recharge area on account of its high permeability value. From a chemical view point, two main groups of water can be distinguished: calcium– magnesium–bicarbonate-type and calcium–magnesium– chloride–sulphate-type waters. The first group reflects the dissolution of the carbonate rocks; the second group probably originates from circulation within flyschoid sediments. Three water wells differ from the other samples due to their relatively high Na and K content, which probably is to be referred to a marked interaction with the ‘‘Calcareniti di Corleone’’ formation, which is rich in glauconite [(K, Na)(Fe3+, Al, Mg)2(Si, Al)4O10(OH)2]. In accordance with WHO guidelines for drinking water (2004), almost all the samples collected can be considered drinkable, with the exception of four of them, whose NO3 -, F- and Na+ contents exceed the limits. On the contrary, the sampled groundwater studied is basically suitable for irrigation.
    Description: Published
    Description: 885-898
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: Water quality ; Environmental isotopes ; Geochemistry ; Sicily ; 03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2017-04-04
    Description: Volcanic and geothermal areas are one of the major natural sources of H2S to the atmosphere. Its environmental impact is often the main cause of the opposition to the development of geothermal energy exploitation programs. In this paper we analyze the air concentrations and dispersion pattern of naturally emitted H2S at the geothermal area of Sousaki (Corinthia, Greece). Measurements, made with a network of passive samplers, evidence a rapid decrease of concentration values away from the emission points. The fact that the decrease is more pronounced in the summer with respect to the winter indicates that it is not only due to a dilution effect, but also to redox reactions favoured by higher temperatures and intense sunlight typical of the summer period.
    Description: Published
    Description: 1723-1728
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Hydrogen sulphide ; Environmental impact of volcanic activity ; Gas hazard ; Passive samplers ; 01. Atmosphere::01.01. Atmosphere::01.01.03. Pollution ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2017-04-04
    Description: A revised Italian strong motion archive has become available since July 2007, including all the records of the strongest events occurred from 1972 to 2004. It contains the uncorrected and corrected accelerograms and the metadata relevant to seismic events, recording stations and instruments added after a careful revision. The availability of this archive allowed us to perform a first step towards an update of the reference ground motion prediction equations for Italy, which were evaluated by Sabetta and Pugliese in (Bull Seismol Soc Am 77:1491–1513, 1987), for peak ground acceleration and velocity, and subsequently extended to the 5% damped pseudovelocity response spectra in 1996. A subset with the 27 major earthquakes occurred in Italy from 1972 to 2002, in the magnitude range 4.6–6.9, was extracted and 235 good quality waveforms were selected, recorded at distances up to 183 km. The goodness of fit of the Sabetta and Pugliese (Bull Seismol Soc Am 86:337–352, 1996) model was explored using two independent statistical approaches (Spudich et al. Bull Seismol Soc Am 89:1156–1170, 1999 and Scherbaum et al. Bull Seismol Soc Am 94:2164– 2185, 2004). The results obtained show that the Sabetta and Pugliese (Bull Seismol Soc Am 77:1491–1513, 1987) does not adequately fit the new strong-motion data set, for its small standard deviation and its non-zero bias. In particular, the most noteworthy result is that the Sabetta and Pugliese (Bull Seismol Soc Am 77:1491–1513, 1987) over-predicts peak ground acceleration and velocity at rock sites. New coefficients for the prediction of horizontal peak ground acceleration, peak ground velocity and acceleration response spectra, adopting the same functional form in Sabetta and Pugliese (Bull Seismol Soc Am 77:1491–1513, 1987), were then evaluated in order to fit the new data set. This paper illustrates the steps made to update the existing ground motion prediction equations for Italy, discusses their limitations and provides the basis for future developments.
    Description: Published
    Description: 591–608
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: reserved
    Keywords: ground motion prediction ; equation ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
    Publication Date: 2017-04-04
    Description: The Italian Accelerometic Archive (ITACA) was created in 2007 during a joint project between the Italian Institute for Geophysics and Vulcanology (Istituto Nazionale di Geofisica e Vulcanologia, INGV) and the Italian Civil Protection (Dipartimento della Protezione Civile, DPC). The project, started in 2006, had the aim of filling the data gap of existing strong motion databases and facilitating strong motion data users in obtaining good quality waveforms, through the collection, homogenization and distribution of strong motion data acquired during the period 1972-2004 in Italy by different institutions (Ente Nazionale per l’Energia Elettrica, ENEL, Italian electricity company; Ente per le Nuove tecnologie, l’Energia e l’Ambiente, ENEA, Italian energy and environment organization DPC). The compiled database contains 2182 three-component waveforms generated by 1008 earthquakes with a maximum moment magnitude of 6.9 (1980 Irpinia earthquake) and can be accessed on-line at the portal denominated ITACA at the site http://itaca.mi.ingv.it, where a wide range of search tools enables the user to interactively retrieve events, recording stations and waveforms with particular characteristics, whose parameters can be specified, as needed, through user friendly interfaces. A range of display options allows users to view data in different contexts, extract and download time series and spectral data. This article describes the state of the art up to 2006 and the activities which led to the completion of the project.
    Description: In press
    Description: 5.2. TTC - Banche dati di sismologia strumentale
    Description: JCR Journal
    Description: open
    Keywords: strong-motion ; database ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    Publication Date: 2017-04-04
    Description: A set of Ground Motion Prediction Equations (GMPEs) for the Italian territory is proposed, exploiting a new strong-motion data set become available since July 2007 through the Italian Accelerometric Archive (ITACA). The data set is composed by 561 three-component waveforms from 107 earthquakes with moment magnitude in the range 4.0–6.9, occurred in Italy from 1972 to 2007 and recorded by 206 stations at distances up to 100 km. The functional form used to derive GMPEs in Italy (Sabetta and Pugliese in Bull Seismol Soc Am 86(2):337–352, 1996) has been modified introducing a quadratic term for magnitude and a magnitude-dependent geometrical spreading. The coefficients for the prediction of horizontal and vertical peak ground acceleration, peak ground velocity and 5% damped acceleration response spectra are evaluated. This paper illustrates the new data set, the regression analysis and the comparisons with recently derived GMPEs in Europe and in the Next Generation Attenuation of Ground Motions (NGA) Project.
    Description: In press
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: open
    Keywords: ground motion ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
    Publication Date: 2017-04-04
    Description: Large variations of the CO2 flux through the soil were observed between November 2002 and January 2006 at Mt. Etna volcano. In many cases, the CO2 flux was strongly influenced by changes in air temperature and atmospheric pressure. A new filtering method was then developed to remove the atmospheric influences on soil CO2 flux and, at the same time, to highlight the variations strictly related to volcanic activity. Successively, the CO2 corrected data were quantitatively compared with the spectral amplitude of the volcanic tremor by cross correlation function, cross-wavelet spectrum and wavelet coherence. These analyses suggested that the soil CO2 flux variations preceded those of volcanic tremor by about 50 days. Given that volcanic tremor is linked to the shallow (a few kilometer) magma dynamics and soil CO2 flux related to the deeper (*12 km b.s.l.) magma dynamics, the “delayed similarity” between the CO2 flux and the volcanic tremor amplitude was used to assess the average speed in the magma uprising into the crust, as about 170–260 m per day. Finally, the large amount of CO2 released before the onset of the 2004–2005 eruption indicated a deep ingression of new magma, which might have triggered such an eruption.
    Description: In press
    Description: N/A or not JCR
    Description: reserved
    Keywords: Mt. Etna ; Soil CO2 flux ; Volcanic tremor ; Cross-wavelet spectrum ; Wavelet coherence ; Cross correlation function ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 15
    Publication Date: 2017-04-04
    Description: New Sr and Nd isotope data for whole rocks, glasses and minerals are combined to reconstruct the nature and origin of mixing end-members of the 200 km3 trachytic to phonolitic Campanian Ignimbrite (Campi Flegrei, Italy) magmatic system. The least-evolved magmatic end-member shows equilibrium between host glass and the majority of the phenocrysts and is less radiogenic in Sr and Nd than the most-evolved magma. On the contrary, only the Fe-rich pyroxene from the most-evolved erupted magma is in equilibrium with the matrix glass, while all other minerals are in isotopic disequilibrium. These magmas mixed prior to and during the Campanian Ignimbrite eruption and minerals were freely exchanged between the magma batches. Combining the results of the geochemical investigations on magma end-members with geophysical and geological data, we develop the following scenario. In stage 1, a parental, less differentiated magma rose into the middle crust, and evolved through combined crustal assimilation and crystal fractionation. In stage 2, the differentiated magma rose to shallower depth, fed the pre-Campanian Ignimbrite activity and evolved by further open-system processes into the most-evolved and most-radiogenic Campanian Ignimbrite end-member magma. In stage 3, new trachytic magma, isotopically distinct from the pre-Campanian Ignimbrite magmas, rose from ca. 6 km to shallower depth, recharged the most-evolved pre-Campanian Ignimbrite magma chamber, and formed the large and stratified Campanian Ignimbrite magmatic system. During the course of the Campanian Ignimbrite eruption, the two layers were tapped separately and/or simultaneously, and gave rise to the range of chemical and isotopic values displayed by the Campanian Ignimbrite pumices, glasses and minerals.
    Description: Published
    Description: 285-300
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Campanian Ignimbrite ; Radiogenic isotopes ; Mixing process ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 16
    Publication Date: 2017-04-04
    Description: National seismic risk maps are an important risk mitigation tool as they can be used for the prioritization of regions within a country where retrofitting of the building stock or other risk mitigation measures should take place. The production of a seismic risk map involves the convolution of seismic hazard data, vulnerability predictions for the building stock and exposure data. The seismic risk maps produced in Italy over the past 10 years are compared in this paper with recent proposals for seismic risk maps based on state-of-the-art seismic hazard data and mechanics-based vulnerability assessment procedures. The aim of the paper is to open the discussion for the way in which future seismic risk maps could be produced, making use of the most up-to-date information in the fields of seismic hazard evaluation and vulnerability assessment.
    Description: Italian Ministry of Research and Higher Education (MIUR—Ministero dell’Università e della Ricerca) through the financing of the project AIRPLANE (Advancing Interdisciplinary Research PLAtform on volcanoes aNd Earthquakes)
    Description: In press
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: JCR Journal
    Description: reserved
    Keywords: Seismic risk ; Seismic hazard ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 17
    Publication Date: 2017-04-04
    Description: We show the magnetic model of the Selli-Vavilov region. The Selli Line is known as the northwestern edge of the southern Tyrrhenian basin. The tectonic evolution of the Tyrrhenian basin is dominated by a Tortonian - Quaternary extension through the eastward movement of the Apennine subduction system. This migration has generated a diffuse stretching of the continental crust with the emplacement of new oceanic material. This latter occurred in several localized zones where the eastward retreating of the Ionian subduction system produced a strong depletion of the crust with formation of basins and correlated spreading. Nowadays the presence of oceanic crust is confirmed through direct drilling investigation but a complete mapping of the oceanic crustal distribution is still lacking. The Selli-Vavilov region shows a differentiated crustal setting where seamount structures, the oceanic basement portions and continental crust blocks are superimposed. To this aim, a 2D inversion of the magnetic data of this region was conducted to define buried structures. The magnetic susceptibility pattern was computed by solving the least squares problem of the misfit between the predicted and real data for separated wavebands. This method produced two 2D models of the high and low frequency fields of the Selli-Vavilov region. The two apparent susceptibility maps provide different information for distinct ranges of depth. The results of the inversions were also combined with seismic data of the Selli region highlighting the position of the highly-magnetized buried bodies. The results confirm a role for the Selli Line as a deep crustal boundary dividing the Sardinian passive domain from the easternmost active region where different oceanic structures are located. The Selli Line has worked as a detachment fault system which has moved eastward. Finally, the Selli-Vavilov region may be interpreted as a tectonic result due to a passive asymmetrical rift occurred between the Tortonian and Pliocene.
    Description: Published
    Description: 251-266
    Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
    Description: 3.4. Geomagnetismo
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: Geomagnetism ; Tectonics ; Geodynamics ; Inversion ; Oceanic crust ; Volcanic structure ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
    Publication Date: 2017-04-04
    Description: Cross-spectral analysis of ULF wave measurements recorded at ground magnetometer stations closely spaced in latitude allows accurate determinations of magnetospheric field line resonance (FLR) frequencies. This is a useful tool for remote sensing temporal and spatial variations of the magnetospheric plasma mass density. The spatial configuration of the South European GeoMagnetic Array (SEGMA, 1.56 〈 L 〈 1.89) offers the possibility to perform such studies at low latitudes allowing to monitor the dynamical coupling between the ionosphere and the inner plasmasphere. As an example of this capability we present the results of a cross-correlation analysis between FLR frequencies and solar EUV irradiance (as monitored by the 10.7-cm solar radio flux F10.7) suggesting that changes in the inner plasmasphere density follow the short-term (27-day) variations of the solar irradiance with a time delay of 1–2 days. As an additional example we present the results of a comparative analysis of FLR measurements, ionospheric vertical soundings and vertical TEC measurements during the development of a geomagnetic storm.
    Description: Published
    Description: 25-27
    Description: 1.6. Osservazioni di geomagnetismo
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: JCR Journal
    Description: reserved
    Keywords: ULF waves ; Field line resonance ; Remote sensing ; Solar activity ; Plasmasphere ; Ionosphere ; 01. Atmosphere::01.02. Ionosphere::01.02.02. Dynamics ; 01. Atmosphere::01.02. Ionosphere::01.02.04. Plasma Physics ; 01. Atmosphere::01.03. Magnetosphere::01.03.03. Magnetospheric physics ; 05. General::05.07. Space and Planetary sciences::05.07.01. Solar-terrestrial interaction
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 19
    Publication Date: 2017-04-04
    Description: Following the 2001 and 2002–2003 flank eruptions, activity resumed at Mt. Etna on 7 September 2004 and lasted for about 6 months. This paper presents new petrographic, major and trace element, and Sr–Nd isotope data from sequential samples collected during the entire 2004–2005 eruption. The progressive change of lava composition allowed defining three phases that correspond to different processes controlling magma dynamics inside the central volcano conduits. The compositional variability of products erupted up to 24 September is well reproduced by a fractional crystallization model that involves magma already stored at shallow depth since the 2002–2003 eruption. The progressive mixing of this magma with a distinct new one rising within the central conduits is clearly revealed by the composition of the products erupted from 24 September to 15 October. After 15 October, the contribution from the new magma gradually becomes predominant, and the efficiency of the mixing process ensures the emission of homogeneous products up to the end of the eruption. Our results give insights into the complex conditions of magma storage and evolution in the shallow plumbing system of Mt. Etna during a flank eruption. Furthermore, they confirm that the 2004–2005 activity at Etna was triggered by regional movements of the eastern flank of the volcano. They caused the opening of a complex fracture zone extending ESE which drained a magma stored at shallow depth since the 2002–2003 eruption. This process favored the ascent of a different magma in the central conduits, which began to be erupted on 24 September without any significant change in eruptive style, deformation, and seismicity until the end of eruption.
    Description: Published
    Description: 781–793
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: Geochemistry ; Isotopic compositions ; Magma feeding system ; Magma mixing ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
    Publication Date: 2022-05-25
    Description: © 2008 The Author. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Environmental Fluid Mechanics 8 (2008): 551-560, doi:10.1007/s10652-008-9076-5.
    Description: Experiments are reviewed in which a two-layer salt-stratified tank of water was mixed by turbulence. The density profile began as a single step and evolved to a smooth mixed profile. The turbulence was generated by many excursions of a horizontally moving vertical rod with Richardson number Ri 〉 0.9 and Reynolds Number Re 〉 600. There was almost perfect collapse of all the profiles to one universal profile as a function of a similarity variable. We develop a theoretical model for a simple mixing law with a buoyancy flux that is a function of internal Richardson number Rii. A similarity equation is found. A flux law that increases with small Rii and decreases with large Rii is considered next. Since no analytical solution is known, the similarity concept is tested by numerically integrating the equations in space and time. With buoyancy flux monotonically increasing with internal Richardson number, the similarity approach is valid for a profile starting from a slightly smoothed step. However, a shock forms for a mixing law with higher initial Rii (so that buoyancy flux decreases with Richardson number) and the similarity approach is invalid for those initial conditions.
    Keywords: Turbulence ; Mixing ; Stratified ; Similarity solution ; Layered fluid
    Repository Name: Woods Hole Open Access Server
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  • 21
    Publication Date: 2022-05-25
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Geo-Marine Letters 29 (2009): 395-404, doi:10.1007/s00367-009-0159-1.
    Description: A program of geophysical mapping and vibracoring was conducted to better understand the geologic evolution of Apalachicola Bay. Analyses of the geophysical data and sediment cores along with age control provided by 34 AMS 14C dates on marine shells and wood reveal the following history. As sea level rose in the early Holocene, fluvial deposits filled the Apalachicola River paleochannel, which extended southward under the central part of the bay and seaward across the continental shelf. Sediments to either side of the paleochannel contain abundant wood fragments, with dates documenting that those areas were forested at 8,000 14C years b.p. As sea level continued to rise, spits formed of headland prodelta deposits. Between ~6,400 and ~2,500 14C years b.p., an Apalachicola prodelta prograded and receded several times across the inner shelf that underlies the western part of the bay. An eastern deltaic lobe was active for a shorter time, between ~5,800 and 5,100 14C years b.p. Estuarine benthic foraminiferal assemblages occurred in the western bay as early as 6,400 14C years b.p., and indicate that there was some physical barrier to open-ocean circulation and shelf species established by that time. It is considered that shoals formed in the region of the present barrier islands as the rising sea flooded an interstream divide. Estuarine conditions were established very early in the post-glacial flooding of the bay.
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  • 22
    Publication Date: 2022-05-25
    Description: © 2009 The Authors. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Marine Biology 156 (2009): 1049-1056, doi:10.1007/s00227-009-1149-6.
    Description: Behavioral observations using a remotely operated vehicle (ROV) in the Gulf of California in March, 2003, provided insights into the vertical distribution, feeding and anatomy of the rare and delicate ctenophore Thalassocalyce inconstans. Additional archived ROV video records from the Monterey Bay Aquarium Research Institute of 288 sightings of T. inconstans and 2,437 individual observations of euphausiids in the Gulf of California and Monterey Canyon between 1989 and 2005 were examined to determine ctenophore and euphausiid prey depth distributions with respect to temperature and dissolved oxygen concentration [dO]. In the Gulf of California most ctenophores (96.9%) were above 350 m, the top of the oxygen minimum layer. In Monterey Canyon the ctenophores were more widely distributed throughout the water column, including the hypoxic zone, to depths as great as 3,500 m. Computer-aided behavioral analysis of two video records of the capture of euphausiids by T. inconstans showed that the ctenophore contracted its bell almost instantly (0.5 s), transforming its flattened, hemispherical resting shape into a closed bi-lobed globe in which seawater and prey were engulfed. Euphausiids entrapped within the globe displayed a previously undescribed escape response for krill (‘probing behavior’), in which they hovered and gently probed the inner surfaces of the globe with antennae without stimulating further contraction by the ctenophore. Such rapid bell contraction could be effected only by a peripheral sphincter muscle even though the presence of circumferential ring musculature was unknown for the Phylum Ctenophora. Thereafter, several live T. inconstans were collected by hand off Barbados and microscopic observations confirmed that assumption.
    Description: Supported by the David and Lucile Packard Foundation and NOAA Grant #NA06OAR4600091.
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  • 23
    Publication Date: 2022-05-25
    Description: © 2008 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Environmental Fluid Mechanics 8 (2008): 495-509, doi:10.1007/s10652-008-9107-2.
    Description: Estuarine turbulence is notable in that both the dissipation rate and the buoyancy frequency extend to much higher values than in other natural environments. The high dissipation rates lead to a distinct inertial subrange in the velocity and scalar spectra, which can be exploited for quantifying the turbulence quantities. However, high buoyancy frequencies lead to small Ozmidov scales, which require high sampling rates and small spatial aperture to resolve the turbulent fluxes. A set of observations in a highly stratified estuary demonstrate the effectiveness of a vessel-mounted turbulence array for resolving turbulent processes, and for relating the turbulence to the forcing by the Reynolds-averaged flow. The observations focus on the ebb, when most of the buoyancy flux occurs. Three stages of mixing are observed: (1) intermittent and localized but intense shear instability during the early ebb; (2) continuous and relatively homogeneous shear-induced mixing during the mid-ebb, and weakly stratified, boundary-layer mixing during the late ebb. The mixing efficiency as quantified by the flux Richardson number Rf was frequently observed to be higher than the canonical value of 0.15 from Osborn (J Phys Oceanogr 10:83–89, 1980). The high efficiency may be linked to the temporal–spatial evolution of shear instabilities.
    Description: The funding for this research was obtained from ONR Grant N00014-06-1-0292 and NSF Grant OCE-0729547.
    Keywords: Turbulence ; Estuaries ; Shear instability ; Buoyancy flux
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  • 24
    Publication Date: 2022-05-25
    Description: © 2009 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in JARO - Journal of the Association for Research in Otolaryngology 10 (2009): 497-509, doi:10.1007/s10162-009-0174-y.
    Description: The dynamic displacement of the semicircular canal cupula and modulation of afferent nerve discharge were measured simultaneously in response to physiological stimuli in vivo. The adaptation time constant(s) of normal cupulae in response to step stimuli averaged 36 s, corresponding to a mechanical lower corner frequency for sinusoidal stimuli of 0.0044 Hz. For stimuli equivalent to 40–200 deg/s of angular head velocity, the displacement gain of the central region of the cupula averaged 53 nm per deg/s. Afferents adapted more rapidly than the cupula, demonstrating the presence of a relaxation process that contributes significantly to the neural representation of angular head motions by the discharge patterns of canal afferent neurons. We also investigated changes in time constants of the cupula and afferents following detachment of the cupula at its apex—mechanical detachment that occurs in response to excessive transcupular endolymph pressure. Detached cupulae exhibited sharply reduced adaptation time constants (300 ms–3 s, n = 3) and can be explained by endolymph flowing rapidly over the apex of the cupula. Partially detached cupulae reattached and normal afferent discharge patterns were recovered 5–7 h following detachment. This regeneration process may have relevance to the recovery of semicircular canal function following head trauma.
    Description: Financial support was provided by the NIDCD R01 DC06685 (Rabbitt) and NASA GSRP 56000135 & NSF IGERT DGE- 9987616 (Breneman).
    Keywords: Vestibular ; Inner ear micromechanics ; Cupula regeneration ; Angular motion sensation ; Afferent response dynamics
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  • 25
    Publication Date: 2022-05-26
    Description: © 2009 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Coral Reefs 28 (2009): 327-337, doi:10.1007/s00338-009-0466-z.
    Description: Design and decision-making for marine protected areas (MPAs) on coral reefs require prediction of MPA effects with population models. Modeling of MPAs has shown how the persistence of metapopulations in systems of MPAs depends on the size and spacing of MPAs, and levels of fishing outside the MPAs. However, the pattern of demographic connectivity produced by larval dispersal is a key uncertainty in those modeling studies. The information required to assess population persistence is a dispersal matrix containing the fraction of larvae traveling to each location from each location, not just the current number of larvae exchanged among locations. Recent metapopulation modeling research with hypothetical dispersal matrices has shown how the spatial scale of dispersal, degree of advection versus diffusion, total larval output, and temporal and spatial variability in dispersal influence population persistence. Recent empirical studies using population genetics, parentage analysis, and geochemical and artificial marks in calcified structures have improved the understanding of dispersal. However, many such studies report current self-recruitment (locally produced settlement/settlement from elsewhere), which is not as directly useful as local retention (locally produced settlement/total locally released), which is a component of the dispersal matrix. Modeling of biophysical circulation with larval particle tracking can provide the required elements of dispersal matrices and assess their sensitivity to flows and larval behavior, but it requires more assumptions than direct empirical methods. To make rapid progress in understanding the scales and patterns of connectivity, greater communication between empiricists and population modelers will be needed. Empiricists need to focus more on identifying the characteristics of the dispersal matrix, while population modelers need to track and assimilate evolving empirical results.
    Description: Work by CB Paris was supported by the National Science Foundation grant NSF-OCE 0550732. Work by M-A Coffroth and SR Thorrold was supported by the National Science Foundation grant NSF-OCE 0424688. Work by TL Shearer was supported by an International Cooperative Biodiversity Group grant R21 TW006662-01 from the Fogarty International Center at the National Institutes of Health.
    Keywords: Connectivity ; Larval dispersal ; Marine protected areas ; Resilience ; Replacement ; Genetics
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  • 26
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    The visual computer 15 (1999), S. 90-99 
    ISSN: 1432-2315
    Keywords: Key words: Cloth deformation ; Geometric constraint ; Geometric physical method ; Constrained finite element method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
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  • 27
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    The visual computer 15 (1999), S. 509-518 
    ISSN: 1432-2315
    Keywords: Key words: Smoothing – Diffusion systems – Bias and tension controls
    Source: Springer Online Journal Archives 1860-2000
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  • 28
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    The visual computer 15 (1999), S. 483-493 
    ISSN: 1432-2315
    Keywords: Key words: Interpolation – Parametric curves – Convexity preservation – Control point form
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: C 2 continuous convexity-preserving parametric curves in ℝ2 is presented. The control point form method, which was developed in the field of numerical grid generation, is used here to construct interpolating curves. Good control over the shape of the curves is obtained thanks to the capability of the proposed approach to interpolate not only the data points, but also some directions suitably associated with them.
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  • 29
    ISSN: 1432-234X
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    Topics: Biology
    Notes: Abstract Antennal sensilla were compared in females and males of two sympatric mymarid Hymenoptera, Anaphes victus and A. listronoti which are, respectively, solitary and gregarious parasitoids of eggs of the carrot weevil Listronotus oregonensis (Coleoptera, Curculionidae). Both species are morphologically very similar in the area where they are sympatric. The external morphology of the sensilla was studied using scanning electron microscopy. Female antennae have seven different types of sensilla, morphologically similar in the two species: trichoid sensilla, which are putative mechanosensilla, sensilla chaetica types 1, 3 and 4, which are presumably contact chemosensilla, and sensilla chaetica type 2 and basiconic and placoid sensilla, which are presumed to be olfactory sensilla. The major difference between the two species is the number of sensilla chaetica type 4, of which 6–9 are found on the antennal club in A. victus, while 10–12 are present in A. listronoti. The antennae of the males of both species are similar in morphology and in the number and distribution of their four types of sensilla, i.e. trichoid sensilla, sensilla chaetica type 1 and basiconic and placoid sensilla.
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  • 30
    ISSN: 1432-234X
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    Notes: Abstract  In this study a ground-dwelling (Eublepharis macularius) and a highly specialised climbing (Gekko gecko) lizard were chosen as study objects. The fore- and hindlimbs of two individuals of each species were dissected, and muscle masses, mean fibre lengths, cross-sectional areas and moment arms were determined. Special attention was paid to general muscle architecture (origin, insertion, fibre orientation, etc.) and pennation angles. Using these variables (cross sectional areas and moment arms), maximal moments exertable across the shoulder/hip, elbow/knee and wrist/ankle were calculated for both species. In accordance with the biomechanical predictions related to the preferred locomotor substrate of each species (i.e. level running for E. macularius and climbing for G. gecko), the results of this study indicate that climbers such as G. gecko generally possess powerful retractor muscles crossing the shoulder and hip joints. Additionally, the specialised climber is able to exert higher flexion moments across the elbow, which prevents the animals from falling backwards. However, G. gecko appears to be constrained in its ankle extension capabilities by the presence of the adhesive toe pads. The level-running species, on the other hand, shows a relatively stronger development of the extensor muscles in the lower limbs, allowing these lizards to run in an erect posture. In general, both species show large similarities on a gross morphological level as expected when considering their phylogenetic relatedness. Adaptations to their preferred locomotor substrate only become apparent when considering the functional properties (i.e. joint moments) of the appendicular musculature.
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  • 31
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    Zoomorphology 119 (1999), S. 23-35 
    ISSN: 1432-234X
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    Topics: Biology
    Notes: Pyxicephalus adspersus , is exceptional among living frogs. Embryonic development, larval phase, and metamorphosis can be completed in 17 days at a temperature of 29°C. The metamorphosis only takes 5 days. The present study shows that, despite the unusually short larval phase in P. adspersus, the state of skeletal differentiation reached at the end of metamorphosis is similar to that of other frog species. There is no shift of cranial bone formation postmetamorphosis as could have been expected and is known from other species. The majority of compared species are particularly similar in the sequence of bone formation in the postcranial skeleton. However, there are clear differences among species in the timing of these events relative to the larval growth trajectory, absolute time, and certain developmental markers, such as external limb differentiation. For example, skeletogenesis and externally visible limb differentiation are only loosely integrated. Interspecific comparisons show that, in P. adspersus, the early onset of skeletal ossification is an unusual feature among frogs. Freshly metamorphosed froglets of P. adspersus are already distinct from comparable stages of other species in having strong jaws, fang-like teeth, and a squamosal-maxilla contact. The latter stabilizes the maxillary arcade and the suspensorium and might relate to the ability to catch and swallow very large vigorous prey, such as siblings, shortly after metamorphosis. The presence of a complete set of dermatocranial elements and postmetamorphic ossification of only the sphenethmoid and operculum are considered plesiomorphic features, whereas the much less completely ossified skulls of metamorphosed froglets, particularly in Bufo and Hamptophryne, are likely apo- morphic developmental traits within the Anura.
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  • 32
    ISSN: 1432-234X
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    Notes: Abstract  The phylogenetic position of the Clitellata within the Annelida is still in debate. It is unresolved whether they are a basal group, resembling the stem species of the Annelida, or a highly derived subtaxon, which evolved from a polychaete-like ancestor. A factor often ignored in this discussion is the site of the supraoesophageal ganglion (brain). Its position in the Clitellata, far behind the prostomium, can be regarded as a secondary structural adaptation to a life spent burrowing through relatively firm terrestrial substrates. Such a habit probably led to the complete elimination of prostomial appendages and a marked reduction in size of the prostomium, resulting in a displacement of the brain into following segments. This interpretation of the sequence of events corroborates the view that the Clitellata are a highly derived subtaxon of the primarily marine Annelida. The development of the central nervous system of Enchytraeus crypticus (”Oligochaeta”) was analysed by immunohistochemical methods in combination with confocal laser scanning microscopy. A detailed description of neural structures, including the formation and arrangement of segmental nerves, is given for significant developmental stages. Labelling of neural structures using antibodies against acetylated α-tubulin and serotonin clearly shows that the cerebral ganglion initially develops within the prostomium. In the course of embryonic development it is shifted backwards into segment III. Thus the posterior relocation of the brain, which is inferred as having occurred in the phylogeny of the Clitel- lata, can be demonstrated in the ontogeny of E. crypticus.
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  • 33
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    Notes: Abstract  Recent reports indicate that neuronal elements develop in early larval stages of some Gastropoda from the Pulmonata and Opisthobranchia prior to the appearance of any ganglia of the future adult central nervous system (CNS). The present study describes similar early neuronal elements in Crepidula fornicata. A posterior FMRFamide-like immunoreactive (LIR) cell with anteriorly projected fibers was observed in the trochophore stage. Additional FMRFamide-LIR and serotonin-LIR cells and fibers were found in the apical organ in the trochophore and early veliger stages. FMRFamide-LIR and serotonin-LIR projections to the velum and foot were also detected at this time. As the veliger developed, peripheral FMRFamide-LIR and later catecholaminergic cells were located in the foot region. Also during this stage, catecholaminergic cells and processes were observed near the mouth. In addition, this study tentatively identified the first serotonin- and FMRFamide-LIR cells and fibers within the developing ganglia of the adult CNS, which appeared in close proximity to the earlier developing elements. These observations are consistent with the hypothesis that, in addition to its presumed role in the control of larval behaviors, the larval nervous system guides the development of the adult CNS. Larvae from the class Bivalvia and other invertebrate phyla also have neuronal elements marked by the presence of FMRFamide, serotonin, and catecholamines, and, therefore, this study may provide additional insights into phylogenetic relationships of the Gastropoda with other representatives of the Mollusca and different invertebrate phyla.
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  • 34
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    Zoomorphology 119 (1999), S. 81-91 
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    Topics: Biology
    Notes: Abstract  The eyes of different larval stages and juveniles of Atlanta peroni are generally composed of a cornea, a lens and a retina. In juveniles a distinct pigmented shield is visible and an enormous humour is located behind the lens. Larvae have only two sensory cells and the photoreceptors are of the ciliary type. In juveniles a striking feature is the shape of the retina. It is ribbon-shaped and new sensory cells are present which are arranged in three rows. The photoreceptors are of the ciliary type as well. Contrary to the arrangement in larvae, the ciliary plasmalemma in juveniles forms numerous lamellar stacks. In accordance with the sensory cells the stacks are organized in three parallel rows. The lamellae of adjacent stacks within a row overlap each other. The latter unique feature has not yet been found in any other representative of the Heteropoda. These findings demonstrate that (a) the eyes are altered during the development from larvae into juveniles, (b) the larval sensory cells are reduced and replaced by new sensory cells in juveniles and (c) the eyes of juvenile and adult A. peroni are well adapted for their life as visual predators.
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  • 35
    ISSN: 1432-234X
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    Notes: Abstract  Two independent methods of comparison, serial homology and phylogenetic character mapping, are employed to investigate the evolutionary origin of the noctuoid moth (Noctuoidea) ear sensory organ. First, neurobiotin and Janus green B staining techniques are used to describe a novel mesothoracic chordotonal organ in the hawkmoth, Manduca sexta, which is shown to be serially homologous to the noctuoid metathoracic tympanal organ. This chordotonal organ comprises a proximal scolopidial region with three bipolar sensory cells, and a long flexible strand (composed of attachment cells) that connects peripherally to an unspecialized membrane ventral to the axillary cord of the fore-wing. Homology to the tympanal chordotonal organ in the Noctuoidea is proposed from anatomical comparisons of the meso- and metathoracic nerve branches and their corresponding peripheral attachment sites. Second, the general structure (noting sensory cell numbers, gross anatomy, and location of peripheral attachment sites) of both meso- and metathoracic organs is surveyed in 23 species representing seven superfamilies of the Lepidoptera. The structure of the wing-hinge chordotonal organ in both thoracic segments was found to be remarkably conserved in all superfamilies of the Macrolepidoptera examined except the Noctuoidea, where fewer than three cells occur in the metathoracic ear (one cell in representatives of the Notodontidae and two cells in those of other families examined), and at the mesothoracic wing-hinge (two cells) in the Notodontidae only. By mapping cell numbers onto current phylogenies of the Macrolepidoptera, we demonstrate that the three-celled wing-hinge chordotonal organ, believed to be a wing proprioceptor, represents the plesiomorphic state from which the tympanal organ in the Noctuoidea evolved. This ’trend toward simplicity’ in the noctuoid ear contrasts an apparent ’trend toward complexity’ in several other insect hearing organs where atympanate homologues have been studied. The advantages to having fewer rather than more cells in the moth ear, which functions primarily to detect the echolocation calls of bats, is discussed.
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    Topics: Biology
    Notes: Abstract  To investigate structural differences between propulsory and antigravity muscles, the spatial distribution of slow (type I) and fast (type II) muscle fibres in forelimb muscles of two species of small mammals was studied, Galea musteloides and Tupaia belangeri. Serial sections through complete forelimbs were prepared. Following histochemical fibre typing, the forelimbs were reconstructed three-dimensionally using product design software. Most forelimb muscles of both species showed a homogenous distribution of type I fibres. In the supraspinatus and triceps brachii (capita longum et laterale) muscles, however, a segregation of fibre types into ”fast” superficial areas and ”slow” deep regions was observed. Slow regions contained at least 60% type I fibres and were positioned along intramuscular extensions of the tendons of insertion. The functional implications of fibre type regionalization are discussed. An analysis of intramuscular fibre type distribution during postnatal myogenesis revealed no significant differences in muscle fibre differentiation between altricial and precocial juveniles. Differences in locomotor ability probably arise from heterochronic development of connective tissue components (endo- and perimysium).
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  • 37
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    Notes: Abstract  The fine structure of spermiogenesis and spermatozoa in three species of the Macrostomorpha was studied, with emphasis on Bradynectes sterreri. Two centrioles appear during the development of sperm cells, at least in B. sterreri and Paromalostomum fusculum. Initially these organelles have a perpendicular position, but later they come to lie in line with each other. In P. fusculum, the differentiation of rootlet structures inserting on both centrioles was found. However, ciliary axonemes do not grow out, either in B. sterreri or in P. fusculum. These two species, and also Haplopharynx rostratus, have aciliated spermatozoa. The mature male gametes of B. sterreri are characterized by a filiform nucleus, numerous mitochondria, dense bodies irregular in shape, membranous lacunae, a pair of electron-dense lateral ledges and two sets of cortical microtubules in addition to a closed ring of microtubules in the posterior segment of the cell. Both lateral ledges do not originate from the centrioles. ’Lateral ledges’ or ’lateral bristles’ were not observed in spermatozoa of H. rostratus and P. fusculum. Such structures cannot be considered autapomorphic for the Macrostomorpha. The known spermatological characteristics contribute to elucidating the interrelationships of the Macrostomorpha. Haplopharynx and Macrostomida are sister groups. Spermatozoa with cortical microtubules separated into two sets are hypothesized as an autapomorphy of the Macrostomida. The two lateral ledges found in spermatozoa of B. sterreri are discussed to correspond to the pair of ’lateral bristles’ known from Macrostomum species, indicating a sister-group relationship of these two taxa. Apparently, the aciliated spermatozoa of Macrostomorpha species originated from biciliated male gametes. Hence, biciliated spermatozoa are not an evolutionary novelty of the Trepaxonemata, but of the Rhabditophora.
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    Zoomorphology 119 (1999), S. 127-142 
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    Notes: Abstract  Convoluta pulchra is a small worm living in the surface sediment of mud flats where it feeds on diatoms. It is roughly teardrop in shape with a ventral groove in which the mouth sits, and it can move in a variety of ways, readily distorting its body in bending, twisting, and turning motions. Fluorescently labeled probes for filamentous actin revealed the musculature in whole mounts of the worm. In the body wall, the musculature consisted of a grid of circular, longitudinal crossover (that is, with a longitudinal orientation in the anterior half of the body but arcing medially to cross over to the contralateral side of the body behind the level of the mouth), and a few diagonal fibers. Inside the body was a strong, irregular brush of muscles originating at the rostral tip of the body and anchoring laterally and posteriorly along the body wall, and strong dorsoventral muscles flanked the ventral groove. Two fans of muscles in the ventral and dorsal body wall reached posteriorly and laterally; that on the dorsal side originated at junctures of the dorsoventral muscles with the body wall and that on the ventral body wall originated from the mouth. By their positions, certain groups of muscles could be correlated with given movements: the crossover muscles with some turning motions and feeding, and the inner muscles with probing and retraction motions of the rostrum and with a tuck-and-turn motion the worm used to turn itself around. Electron microscopy showed numerous maculae adherentes junctions linking all muscle types and special junctions linking the musculature with the epidermis. The latter myoepidermal junctions were of dimensions larger than those of maculae adherentes and contained an interlaminar material which we believe represents islands of basal matrix comparable to basement membrane.
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    Zoomorphology 119 (1999), S. 143-162 
    ISSN: 1432-234X
    Keywords: Abbreviations L1, L2, L3: instars of larvae ; Lm: mature larva(e)
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    Topics: Biology
    Notes: Abstract  Adhesion to smooth surfaces by means of thin fluid lipid film was studied on living larvae of 71 species of Lepidoptera by a simple ”light reflection method”. The method made it possible to localize exactly the sites of adhesion and to estimate roughly the film thickness, within a certain range. Furthermore, it revealed the general presence of mobile lipid on the entire insect surface. The observations on living larvae were complemented by comparative structural studies of the adhesive parts with light and scanning electron microscopes on preserved specimens of 161 species. Specialized adhesive devices were found in great diversity on larval legs and prolegs, especially in larvae living in the open air on their food plants. Two main surface types of adhesive cuticle were found: (1) cuticle with a flexible smooth surface and (2) cuticle with very numerous small projections (microtrichia) with spatulate and recurved apices. Both the functional implications of the adhesive cuticular structure and the role of the adhesive fluid as well as the evolution of the adhesive devices are discussed. The adhesive effect is due to ”capillary” or meniscus forces.
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    Notes: Abstract  A comparative SEM investigation of the transphragma representing the medioanterior margin of the first abdominal tergum in ditrysian Lepidoptera resulted in the establishment of a directed transformation series of gradual modifications. Most remarkably, an additional phragma, for which the term euphragma is proposed, must be assigned to the ground pattern of the Obtectomera. However, this assumption implies that a subsequent loss of the euphragma must be attributed to the ground patterns of the Axiidae, Copromorphoidea, Doidae, Papilionidae and the Hedylidae. On the other hand, a typical euphragma is also observed in the non-obtectomeran superfamily Sesioidea. Similarly, the phylogenetic significance of the presence of a much smaller circular phragma in the Choreutidae is not yet understood. Either the three taxa (Obtectomera, Sesioidea and Choreutidae) constitute a clade, and secondary modifications have obliterated the euphragma on a number of occasions, or the euphragma has been developed independently on more than one occasion. Potential autapomorphies of various subordinate taxa are also discussed.
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  • 41
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    Notes: Abstract  Megarhyssa atrata (Pimplinae) is the largest species known amongst Hymenoptera. In its natural habitat, North America, it is a strict parasito¨ıd of Tremex columba (Hymenoptera, Symphyta, Siricidae). The para- site infests xylophagous host larvae buried in wood. The present work describes the complex movements of the ovipositor during oviposition and its flexibility ensuring the positioning of the stylus at the site of boring. These movements are made possible by the unfolding of the intersegmentary membranes (equipped with a secretory internal surface) and by the full rotation of abdominal segments 8 and 9. During this rotation, the stylus of the ovipositor pushes and extends the membranes completely which, as a result, form a translucent disc measuring 2 cm in diameter. The entry of the stylus into wood is helped by another secretion produced at the tip of the valvulae. This lytic secretion destroys wood fibers. With this set of adaptations, the hymenopteran can bore into a thickness of hard wood and reach its host larvae at a depth of 14 cm.
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  • 42
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    Notes: Abstract  The Malpighian tubules of Drosophila hydei and D. melanogaster larvae are composed of two types of cell, principal cells and stellate cells. In the anterior larval Malpighian tubules approximately 26% (D. hydei) and 18% (D. melanogaster), respectively, of all cells are stellate cells. In the larvae of D. melanogaster, the stellate cells are fenestrated and the hemolymph space and tubule lumen are separated only by the basal lamina. Injection of dyes into the hemolymph did not indicate any facilitated transfer of substances through the fenestrated cells. The principal cells of the distal segment are carbonic anhydrase positive indicating transport activity, whereas the stellate cells lack this enzyme. In the stellate cells of the transitional segment, the sodium content is strikingly high in comparison to the neighbouring principal cells and lumen where no sodium was detected. This finding indicates that stellate cells reabsorb sodium as supposed earlier in 1969 by Berridge and Oschman (Tissue Cell 1:247–272).
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    Mathematische Annalen 314 (1999), S. 39-52 
    ISSN: 1432-1807
    Keywords: Mathematics Subject Classification (1991):32M05, 32S20, 32A27, 58F08
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    Mathematische Annalen 314 (1999), S. 291-326 
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    Keywords: Mathematics Subject Classification (1991):14H60
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    Mathematische Annalen 314 (1999), S. 403-447 
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    Keywords: Mathematics Subject Classification (1991):32H50, 58F23, 58F15
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    Mathematische Annalen 314 (1999), S. 601-612 
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    Keywords: Mathematics Subject Classification (1991):14P05, 14P25
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    Mathematische Annalen 314 (1999), S. 175-196 
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    Keywords: Mathematics Subject Classification (1991):11G09, 11F03
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    Mathematische Annalen 314 (1999), S. 265-283 
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    Keywords: Mathematics Subject Classification (1991):11E25, 11E76
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    Mathematische Annalen 314 (1999), S. 347-367 
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    Keywords: Mathematics Subject Classification (1991):46L55, 46L40, 28D20
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    Mathematische Annalen 314 (1999), S. 449-467 
    ISSN: 1432-1807
    Keywords: Mathematics Subject Classification (1991):18G55, 55P99, 55R05, 55R20, 55T20, 55U35, 57T30, 57T35
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    Mathematische Annalen 314 (1999), S. 667-702 
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    Keywords: Mathematics Subject Classification (1991):11R33, 19A31, 11R29
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    Radiation and environmental biophysics 38 (1999), S. 23-29 
    ISSN: 1432-2099
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    Topics: Biology , Physics
    Notes: Abstract Nucleotide conformation and dynamics are important for the study of radiation damage to DNA at the atomic level. It is necessary to study not only normal oligonucleotide structure but also those containing modified bases which result from interaction with OH-radicals. There are now over 8000 atomic coordinate entries in the Brookhaven Protein Data Bank, of which over 900 relate to experimentally determined structures of nucleic acids and nucleic acid/protein complexes. We review some of these data which have led to the elucidation of novel DNA conformations, insight into DNA sequence specificity and knowledge of protein/DNA interactions. Further understanding of the conformation, stability and dynamics of nucleic acids has come from molecular modelling. We have used such techniques to study chemical modifications to bases such as alkylation of thymine and guanine and the effects of curvature in longer sequences. Recent improvements in this area include the inclusions of explicit counter-ions and solvent molecules, the use of Particle Mesh Ewald methods to incorporate the long-range electrostatic interactions and the use of longer time scale simulations. We have employed these methods to analyse the effects of incorporation of 8-oxodeoxyguanosine into duplex DNA. This lesion is a common result of radiation damage and is known to have important effects in mutagenesis, cancer and ageing.
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    Radiation and environmental biophysics 38 (1999), S. 72-72 
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    Radiation and environmental biophysics 38 (1999), S. 105-109 
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    Notes: Abstract  By the method of gel electrophoresis, radiation-induced DNA single- and double-strand breaks (SSB, DSB) were studied with a model system of pBR322 solution in vitro in the presence of ·OH radical scavengers, mannitol and TE (10–2 mol dm–3 Tris and 10–3 mol dm–3 ethylene diamine tetra-acetic acid). Experiments showed that SSB resulted from one-hit events of radiation energy deposition and DSB resulted from both one-hit and two-hit energy deposition events and so were distinguished into two classes of αDSB and βDSB. Moreover, α/β, where α is the number of DSB per unit dose induced in one irradiation event and β the number of DSB per unit squared dose induced by the combination of two independent SSB, was related to the scavenging capacity, σ, and for σ〉108 s–1,αDSB predominate over DSB. On the other hand, if σ〈2×108 s–1, the measured G(αDSB) decreased in parallel with G(SSB), i.e., G(αDSB)/G(SSB) was a constant. When σ〉2×108 s–1, G(αDSB) decreased slightly so that the ratio of αDSB to SSB evidently increased. Therefore, αDSB could be induced by the radical transfer mechanism for σ〈2×108 s–1 and contrarily produced by the local multiply damaged sites (LMDS) mechanism for σ larger than this value. In addition, the distance for two independent complementary SSB forming a DSB was deduced, but no apparent variation of it was found in the wide σ range from ∼105 to ∼109 s–1, which shows that the DNA steric structure was not influenced by mannitol.
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    Radiation and environmental biophysics 38 (1999), S. 133-138 
    ISSN: 1432-2099
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    Topics: Biology , Physics
    Notes: Abstract  The influence of microgravity on the repair of x-ray-induced DNA double-strand breaks was studied in the temperature-conditional repair mutant rad54–3 of diploid yeast Saccharomyces cerevisiae. Cells were exposed on the ground and kept at a low temperature until microgravity conditions were achieved. In orbit, they were incubated at the permissive temperature to allow repair. Before re-entry they were again cooled down and kept at a low temperature until final analysis. The experiment, which was flown on the shuttle Atlantis on flight STS-76 (SMM-03), showed that repair of pre-formed DNA double-strand breaks in yeast is not impaired by microgravity.
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    Radiation and environmental biophysics 38 (1999), S. 175-184 
    ISSN: 1432-2099
    Keywords: Key words Alpha particle ; Deuteron ; Proton ; Biophysical modeling ; Radiation quality influence ; Bacillus subtilis ; DNA density ; Monte Carlo calculations
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    Topics: Biology , Physics
    Notes: Abstract  A new approach to the interpretation of the effects of radiation on cells is described, in which sample particle tracks are constructed using a Monte Carlo computer program and the exposure of cellular targets to these tracks is simulated using a second program known as BIOPHYS. Data on the shapes and DNA contents of the cell nuclei are obtained from the literature. It is assumed that the sensitive material is DNA, and that the target is divided into cubes of approximately 2 nm (the diameter of the DNA helix) per side; the numbers of these cubes containing different numbers of ionizations are derived. Two different methods of analysing the output of BIOPHYS are described. In the first, it is assumed that lethality is caused by the occurrence of a number of ionizations equal to or greater than a certain threshold in one cube; in the second method, it is assumed that only two ionizations are required, in different parts of the cube, but that only some fraction of the cube is sensitive. These models have been applied to the interpretation of the variation of radiosensitivity with a linear energy transfer (LET) of spores of Bacillus subtilis exposed wet and dry, and good fits to the published experimental data were obtained using both models. Fits to experimental data for a range of other cell lines will be presented in a second paper.
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  • 57
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    Notes: Abstract This paper is concerned with the practical implementation of Monte Carlo simulation methods for charged particle transport. The emphasis is on light particles (electrons and positrons) because of the larger scattering and energy straggling effects. Differential cross sections (DCS) for the various interaction mechanisms are described. As the average number of interactions along the particle track increases with the initial energy, detailed simulation becomes unfeasible at high energies. We can then rely on mixed simulation algorithms: hard events (i.e. individual interactions with angular deflection or energy loss larger than given cutoff values) are sampled from the DCS whereas soft events are simulated by means of a multiple scattering approach. Too frequently, the statistical uncertainty of analogue simulation (i.e. strict simulation of the physical interaction process) is found to be so large that results are meaningless. This problem can be partially solved by applying simple variance reduction techniques.
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    Notes: Abstract The effects of different doses of acute and continuous gamma-irradiation on the synthetic activity of rat blood lymphocytes stained with acridine orange were studied by fluorescent microspectrometry. Male rats were exposed to acute gamma-irradiation with doses of 7.5, 4 and 3 Gy, or to continuous irradiation with dose rates of 14.4, 2.1, 1.1 and 0.43 cGy/day, respectively. The changes of the synthetic activity of blood lymphocytes occurred in three main stages after acute gamma-irradiation and in four stages under continuous irradiation. The stages reflect the processes of depression and activation of the immune system under irradiation. Essential differences between the acute and continuous effects were observed in the first stage. After acute gamma-irradiation, the synthetic activity decreased sharply, indicating the predominant contribution of the damaging effect of irradiation, whereas under continuous irradiation, as a result of the stimulatory effect of low-dose irradiation, the synthetic activity increased during the first stage.
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    Radiation and environmental biophysics 38 (1999), S. 57-71 
    ISSN: 1432-2099
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    Topics: Biology , Physics
    Notes: Abstract Three sets of data (population statistics in non-smokers, data from an investigation of the smoking habits of British doctors and a study of Colorado uranium miners) were used to analyse lung cancer in humans as a function of exposure to radon and smoking. One of the aims was to derive implications for radon risk estimates. The data were analysed using a two-mutation radiation carcinogenesis model and a stepwise determination of the model parameters. The basic model parameters for lung cancer were derived from the age dependence fit of the spontaneous lung cancer incidence in non-smokers. The effect of smoking was described by two additional parameters and, subsequently, the effect of radon by three other parameters; these five parameters define the dependence of the two mutation steps on smoking and exposure to radon. Using this approach, a consistent fit and comprehensive description of the three sets of data have been achieved, and the parameters could, at least partly, be related to cellular radiobiological data. The model results explain the different effect of radon on non-smokers and smokers as seen in epidemiological data. Although the analysis was only applied to a limited number of populations, lung cancer incidence as a result of radon exposure is estimated to be about ten times higher for people exposed at the age of about 15 than at about 50, although this effect is masked (especially for smokers) by the high lung cancer incidence from smoking. Using the model to calculate the lung cancer risks from lifetime exposure to radon, as is the case for indoor radon, higher risks were estimated than previously derived from epidemiological studies of the miners' data. The excess absolute risk per unit exposure of radon is about 1.7 times higher for smokers of 30 cigarettes per day than for non-smokers, even though, as a result of the low spontaneous tumour incidence in the non-smokers, the excess relative risk per unit exposure for the smokers is about 20 times lower than for the non-smokers. This prediction could have serious consequences for the transfer of risk estimates between populations. Although the solution of the model presented here is not unique but dependent on the model assumptions, the predictions and risk implications are sufficiently supported to justify a thorough investigation of the applicability of the model to other radon data sets.
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    Radiation and environmental biophysics 38 (1999), S. 97-104 
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    Notes: Abstract  An ion interaction model has been described for simulating positive ion tracks in a variety of media with the capability of interfacing with several secondary electron transport codes. Data are presented for single- and double-differential cross-sections, binding energies, probability density distribution for delocalisation parameters for conductors and tissue, branching ratios and ionisation efficiencies for water vapour and liquid water.
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    Radiation and environmental biophysics 38 (1999), S. 111-115 
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    Notes: Abstract  The biological effects of ion beams on Nicotiana tabacum L., particularly the induction of chromosome aberrations, were investigated. Dry seeds were exposed to 12C5+, 4He2+ and 1H+ beams with linear energy transfer (LET) ranging from 1 to 111 keV/µm and irradiated with gamma-rays. Ion beams were more effective in reducing germination and survival of the seeds than gamma-rays. The LD50 for 12C5+ beams, 4He2+ beams and gamma-rays were 35, 60 and 500 Gy, respectively. The frequencies of mitotic cells with chromosome aberrations, such as chromosome bridges, acentric fragments and lagging chromosomes in the root tip cells of the exposed seeds, increased linearly with increasing doses. Relative biological effectiveness (RBE) values, based on the doses that induced a survival inhibition of 50% and a 10% frequency of aberrant cells, were 14.3–17.5 for the 12C5+ beams, 7.0–8.3 for the 4He2+ beams and 7.8 for the 1H+ beams. Furthermore, the relative ratios of the chromosome aberration types were significantly different between the ion beam and the gamma-ray regimes: chromosome fragments were more frequent in the former, and chromosome bridges in the latter. Based on these results, we concluded that the repair process of initial lesions induced by ion beams may be different from that induced by low- LET radiation.
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    Radiation and environmental biophysics 38 (1999), S. 163-173 
    ISSN: 1432-2099
    Keywords: Key words Charged particles ; Electron transport scheme ; Microdosimetry ; Monte Carlo simulation ; Radiation dosimetry ; Radiotherapy ; Track structure
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    Notes: Abstract  Condensed-history (CH) Monte-Carlo (MC) groups together the vast number of individual charged-particle collisions using multiple scattering theory for elastic angular changes and stopping power for energy losses. CH codes such as EGS4 have been enormously successful in simulating the transport of electrons, for example, in radiotherapy. MC-derived values of the water-to-air stopping-power ratio, s w/air, are used in all modern codes of practice for absolute dose determination in radiotherapy clinics. MC can also directly yield the dose ratio D med/D det for a dosimeter in a medium, and Correlated Sampling has been exploited to increase the efficiency, e. g., the central electrode in an ion chamber (aluminium vs. graphite). The extremely low density of the gas in an ion chamber poses problems for CH codes. However, multiple scattering can now be combined with single scattering and is expected to finally resolve important chamber perturbation effects. An exciting application of CH MC in radiotherapy is the computation of dose distributions in patients. Currently one can achieve an uncertainty around 1% (1 SD) in mm-sized voxels in several minutes for an electron beam and in around an hour for a photon treatment plan on hardware costing less than $20,000, and thus avoid all the various approximations conventionally used to account for inhomogeneities. In the microdosimetry/track structure field, CH codes have shown that the fluence (dΦ/dE) per unit dose at low electron energies is virtually independent of incident particle energy or depth, which simply explains the negligible RBE variation.
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    Radiation and environmental biophysics 38 (1999), S. 201-206 
    ISSN: 1432-2099
    Keywords: Key words Cancer risk modelling ; Chronic myeloid leukemia (CML) incidence ; CML target stem cells ; genome translocation ; Low-dose exposure ; Radiation-induced CML
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    Notes: Abstract  Estimation of the number of hematopoietic stem cells capable of causing chronic myeloid leukemia (CML) is relevant to the development of biologically based risk models of radiation-induced CML. Through a comparison of the age structure of CML incidence data from the Surveillance, Epidemiology, and End Results (SEER) Program and the age structure of chromosomal translocations found in healthy subjects, the number of CML target stem cells is estimated for individuals above 20 years of age. The estimation involves three steps. First, CML incidence among adults is fit to an exponentially increasing function of age. Next, assuming a relatively short waiting time distribution between BCR-ABL induction and the appearance of CML, an exponential age function with rate constants fixed to the values found for CML is fitted to the translocation data. Finally, assuming that translocations are equally likely to occur between any two points in the genome, the parameter estimates found in the first two steps are used to estimate the number of target stem cells for CML. The population-averaged estimates of this number are found to be 1.86×108 for men and 1.21×108 for women; the 95% confidence intervals of these estimates are (1.34×108, 2.50×108) and (0.84×108, 1.83×108), respectively.
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    Radiation and environmental biophysics 38 (1999), S. 219-219 
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    Radiation and environmental biophysics 38 (1999), S. 229-237 
    ISSN: 1432-2099
    Keywords: Key words Ions ; Tumor therapy ; RBE ; Track structure ; Treatment planning ; Carbon beam
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    Notes: Abstract  The elevated relative biological effectiveness (RBE) of heavy ions like carbon is the main reason for their use in radiotherapy and is due to the microscopic distribution of dose inside each particle track. High local doses produce lesions that are expected to have a diminished possibility of repair. Thus, RBE depends on track structure and on the biological repair capacity of the tissue that is affected by the irradiation. For tumor treatment planning with heavy ions, the beam quality and the tissue sensitivity have to be taken into account. Using the dependence of radial dose distribution on particle energy and atomic number on the physical side and x-ray dose response for the repair capacity on the biological side, the response to particle irradiation can be calculated in the local effect model (LEM) and used for treatment planning. This article traces the route from electron emission as the basis of track structure to the RBE calculation and the application in treatment planning.
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    Radiation and environmental biophysics 38 (1999), S. 261-266 
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    Keywords: Key words Iodine uptake ; Lead ; Lithium ; Rats ; Thyroid ; Thyroid hormones
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    Topics: Biology , Physics
    Notes: Abstract  The influence of lead acetate (50 mg per kg body weight) on the 131iodine (131I) biokinetics (uptake and retention) in rat thyroid and serum levels of triiodothyronine (T3) as well as thyroxine (T4) was evaluated as a function of time and in combination with lithium treatment. The 2-h and 24-h uptake of 131I in the thyroid was stimulated significantly by lead treatment. The 24-h uptake showed a maximum stimulation after 4 months of lead treatment. Lithium supplementation, however, showed the opposite effect by reducing the iodine uptake, whereby the maximum decrease was noticed after 2 months of treatment. Further, simultaneous lead and lithium treatment resulted in an even more pronounced increase of 2-h 131I uptake with a maximum after 3 months. However, the 24-h uptake after 3 months and 4 months of treatment did not differ significantly from the lead treated reference groups. The thyroidal biological half-life of 131I (Tbiol) was found to have clearly increased following the lead/lithium treatment. Interestingly, the combined lead/lithium treatment applied for 4 months caused a further growth of Tbiol, thus reflecting an increased retention of 131I. A maximum increase of Tbiol was seen after 2 months of combined treatment. A progressive decline of the circulating T3 and T4 levels following lead or lithium treatment was noticed and was more pronounced after combined treatment.
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    Research in nondestructive evaluation 11 (1999), S. 39-57 
    ISSN: 1432-2110
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract. The remote field eddy current technique is used for dimensioning grooves that may occur in ferromagnetic pipes. We propose a method to estimate the depth and the length of corrosion grooves from the measurement of a pick-up coil signal phase at different positions close to the defect. Groove dimensioning needs the knowledge of the physical relation between measurements and defect dimensions; therefore, finite-element calculations are performed to obtain a parametric algebraic function of the physical phenomena. The parameters of this model function are obtained by an optimization technique. By means of this model and a previously defined general approach, an estimate of groove size may be given. In this approach, algebraic function parameters and groove dimensions are linked through a polynomial function. To validate this estimation procedure, a statistical study has been performed. The approach is proved to be suitable for real measurements.
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    Research in nondestructive evaluation 11 (1999), S. 15-24 
    ISSN: 1432-2110
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract. In this paper we present a complete detection scheme for ultrasonic crack detection in wet ceramics by means of ultrasonic nondestructive techniques. The detection scheme is based on a previous statistical characterization of the ultrasonic grain noise. In these previous works we obtained that the ultrasonic grain noise can be modeled as a K -noise [1, 2]. From this characterization we will prove that the expression of the probability of false alarm (PFA) obtained for a detector of Gaussian envelope pulses over K -noise using the Wigner-Ville Transform (WVT) proposed in reference [3] is valid for the real problem of ultrasonic microcrack detection in wet ceramics.
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    Research in nondestructive evaluation 11 (1999), S. 1-13 
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract. Process control is becoming increasingly important to the high performance applications of aluminum metal—matrix composites. Most processing conditions of metal—matrix composites introduce a degree of anisotropy that results in the directional dependence of material properties. Aluminum alloys reinforced with up to 20 volume % silicon-carbide or alumina particles are examined using ultrasonic velocity measurements. The measurements indicate that these composites are transversely isotropic and thus their elastic properties can be described by the five independent elastic constants C 11 , C 33 , C 44 , C 12 , and C 23 . Anisotropy parameters are determined assuming either a preferred alignment of the matrix crystallites or a preferred alignment of the reinforcement. Comparing measured and theoretical anisotropy parameters for partially aligned reinforcement or for texture shows that neither is the single contributor to anisotropy in the composite material.
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    Research in nondestructive evaluation 11 (1999), S. 81-95 
    ISSN: 1432-2110
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract. The present work investigates the durability of two commercial epoxy adhesives nondestructively using ultrasonic reflection measurements from the interfacial region between the adhesive and the adherend. This method, which is primarily sensitive to the interfacial properties, employs a new specimen geometry that overcomes the drawbacks of the conventional closed adhesive sandwich. The interfacial region was modeled using the spring boundary conditions. The normal and tangential spring constants were determined, as a function of degradation, from normal-incidence longitudinal and shear-wave measurements. Obliquely incident shear-wave measurements were also performed using a newly developed dual-element PVDF transducer. An efficient angular spectrum approach was developed to model the oblique-incidence measurement system, and the predictions of the model were compared with measurements for various levels of degradation.
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    Research in nondestructive evaluation 11 (1999), S. 117-135 
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract. A numerical procedure for the solution of a wave propagation problem in a solder joint with a line crack in its base layer is presented. The two-dimensional ``in-plane'' wave propagation problem for a finite, multilayered body with a line crack in one of the layers is solved by the combined usage of the displacement and the traction BIEM. The discretization of the boundary with parabolic elements far from the crack edge and with quarter-point crack-tip boundary elements containing the correct $O(\sqrt{r})$ behavior for displacement variations at the crack edge is used. Numerical results for a solder joint with real geometry and physical properties are presented. The relations between the wave scattering problems, the solder joint fatigue state estimation, and the reliability and quality of electronic packages is discussed.
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    Research in nondestructive evaluation 11 (1999), S. 97-116 
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    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract. This paper presents a practical new lens design for acoustic microscopy. The new lens provides a factor-of-2 higher resolution than currently available commercial lenses for acoustic microscopy, and a reduction in the influence of surface roughness on the image formation. Analysis, computer simulations, and demonstration examples provide convincing evidence that new lens design works efficiently. Whereas most current lens designs emphasize the use of longitudinal waves, the designs presented here focus on the use of transverse or shear waves. In the present study, two kinds of lens designs have been developed: One is a ``center-sealed'' acoustic lens used at the center frequency of 400 MHz and 1 GHz for use with acoustic tone bursts, and the other is a ``high-NA acoustic lens'' used in the center frequency of 30 MHz for use with short pulses. The center-sealed acoustic lens has its center area aperture sealed to prevent longitudinal waves from traveling into the sample so that the acoustic image is substantially composed of shear wave components. The ``high-NA'' acoustic lens has an aperture with a large aperture angle for exciting shear waves in the object. In this study, the mechanisms of image formation with both of these lenses are described and their features are evaluated.
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    Semigroup forum 59 (1999), S. 461-466 
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    Semigroup forum 59 (1999), S. 470-521 
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    Notes: E -solid semigroups, a theory of e-varieties including appropriate notions of biidentities and biinvariant congruences is presented, such that, together with bifree objects, these notions inherit the properties and interrelations well known from universial algebra. This theory generalizes the previously developed such theory for orthodox semigroups. As an application, the bifree objects in certain e-varieties of E-solid locally orthodox semigroups, which are constructed by means of Malcev products from a varities of bands, groups and completely simple semigroups, are described as subsemigroups in suitable Pastijn products of some bands by relatively bifree completely simple semigroups. As a consequence, it follows that every regular E-solid locally orthodox semigroup regularly divides a so-called solid Pastijn product of a band by a completely simple semigroup.
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    Semigroup forum 58 (1999), S. 5-16 
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    Notes: S : a right S-act A is strongly flat if and only if the functor A\otimes- (from the category of left S-acts into the category of sets) preserves both pullbacks and equalizers. Stenström gave two interpolation-type conditions whose conjunction describes strong flatness. In 1986, P. Normak studied these conditions separately, lablelling them (P) and (E), and investigated their relation to different types of flatness. Bulman-Fleming, in 1991, showed that pullback flatness and strong flatness actually coincide, and several papers have appeared in which condition (P) is discussed. To date, little work has been done on equalizer flat acts. This paper gives some new results connecting condition (E) and equalizer flatness, concentrating on situations in which the two coincide. A description is given of the completely simple and completely 0-simple semigroups (with 1 adjoined) over which this occurs.
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    Semigroup forum 58 (1999), S. 17-68 
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    Notes: E -solid semigroups, a theory of e-varieties including appropriate notions of biidentities and biinvariant congruences is presented, such that, together with bifree objects, these notions inherit the properties and interrelations well known from universal algebra. This theory generalizes the previously developed such theory for orthodox semigroups. As an application, the bifree objects in certain e-varieties of E-solid locally orthodox semigroups, which are constructed by means of Malcev products from varieties of bands, groups and completely simple semigroups, are described as subsemigroups in suitable Pastijn products of some bands by relatively bifree completely simple semigroups. As a consequence, it follows that every regular E-solid locally orthodox semigroup regularly divides a so-called solid Pastijn product of a band by a completely simple semigroup.
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    Semigroup forum 58 (1999), S. 142-151 
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    Notes: G be a connected semi-simple Lie group with finite center and S⊂G a semigroup with interior points. It is proved that S is transitive on a homogenous space G/L only if the action of L on B is minimal and contracting, where B=G/Pis the flag manifold of G asssociated with S. In [5, Thm.6.4] the authors claimed another necessary condition in case G is simple, namely, that L is discrete. It is shown by means of an example that this condition is wrong without the further assumption that G/L is compact.
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    Semigroup forum 58 (1999), S. 156-158 
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    Semigroup forum 58 (1999), S. 267-295 
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    Notes: operator matrix . We introduce a new class of unbounded operator matrices corresponding to these equations and study the spectral theory, compute the adjoint and analyze the generator property of its elements. The abstract results arre illustrated by a series of applications.
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    Semigroup forum 59 (1999), S. 121-125 
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    Notes: L the explicit construction of a 0-simple Rees matrix semigroup is suggested such that the lattice of left annihilators of this semigroup is isomorphic to L.
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    Semigroup forum 91 (1999), S. 1-4 
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    Notes: Oryza sativa L.) research in Southeast Asia. The models successfully simulated crop growth as affected by canopy photosynthesis, sink capacity, and N nutrition. The rather crude plant physiology in these and similar models limits their usefulness in simulating the effect of morphological modifications and the response to various stress factors. Modeling skills developed by SARP in Asian research institutes cannot be maintained without continued coordination from advanced institutes. More basic knowledge on the plant's morphogenesis and feedback mechanisms is required for effective simulation of plant adaptation to complex growth environments, including intercropping, as found in many developing countries. A more rigorous modular approach to modeling is advocated, as well as standardization of modules for well-understood processes, as part of a toolkit for applied research for use in combination with other techniques, including statistical techniques.
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    Semigroup forum 91 (1999), S. 116-121 
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    Notes: Zea mays L.) yields and production costs during the transition from conventional to reduced tillage provide farmers with guidelines for implementing conservation tillage in a subtropical, semiarid environment through evaluation of grain yield and production economics as affected by tillage. Conventional tillage (CT), reduced tillage with wide V-sweeps (RT), and preplant no-tillage (PPNT) were compared for both spring and fall corn production over three years. Grain yields for PPNT were lower than CT in the spring (-9%) and fall (-20%) of the first cropping year. Yields in PPNT were equivalent or up to 12% greater than CT yields in Years 2 and 3. Production costs were lower in the PPNT than in the CT, because of the reduced number of tillage trips over the field. A three-year average of net returns for corn grown in the PPNT spring treatment was $47 ha-1 greater than RT, and $104 ha-1 more than CT systems. Average net returns from PPNT for spring and fall cropping seasons over three years was $23 ha-1 greater than the RT and $104 ha-1 greater than the CT. Greater economic returns and lower production costs of PPNT compared with CT systems for all seasons and years were the result of reduced energy and operator time requirements. The conservation tillage systems (RT and PPNT) resulted in greater economic returns, compared with a CT tillage system, due to both greater yields in dry years and lower production costs in all years.
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    Semigroup forum 91 (1999), S. 24-32 
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    Notes: 2 from the emissions of coal-fired boilers produces by-products that often consist of CaSO4, residual alkalinity, and coal ash. These by-products could be beneficial to acidic soils because of their alkalinity and the ability of gypsum (CaSO4·2H2O) to reduce Al toxicity in acidic subsoils. A 3-yr field experiment was conducted to determine the liming efficacy of a fluidized bed combustion boiler by-product (FBC) that contained 129 g Mg kg-1 as CaMg(CO3)2 and MgO and its effects on surface and subsurface soil chemistry. The FBC was mixed in the surface 10 cm of two acidic soils (Wooster silt loam, an Oxyaquic Fragiudalf, and Coshocton silt loam, an Aquultic Hapludalf) at rates of 0, 0.5, 1, and 2 times each soil's lime requirement (LR). Soils were sampled in 10-cm increments to depths ranging from 20 to 110 cm, and corn (Zea mays L.) and alfalfa (Medicago sativa L.) were grown. Application of Mg-FBC increased alfalfa yields in all six site-years, whereas it had no effect on corn grain yield in five site-years and decreased grain yield in one site-year. Plant tissue concentrations of Mg, S, and Mo were increased by Mg-FBC, while most trace elements were either unaffected or decreased. Application of Mg-FBC at one or two times LR increased surface soil pH to near 7 within 1wk. Although surface soil pH remained near 7 for 2 yr, there was minimal effect on subjacent soil pH. Application of Mg-FBC increased surface soil concentrations of Ca, Mg, and S, which promoted downward movement of Mg and SO4. This had different effects on subsoil chemistry in the two soils: in the high-Ca-status Wooster subsoil, exchangeable Ca was decreased and exchangeable Al was increased, whereas in the high-Al-status Coshocton subsoil, exchangeable Al was decreased and exchangeable Mg was increased. The Mg-FBC was an effective liming material and, because of the presence of both Mg and SO4 , may be more effective than gypsum in ameliorating subsoil Al phytotoxicity.
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    Notes: Sorghum bicolor (L.) Moench] grain yields can be reduced if plants are exposed to freezing temperatures prior to reaching physiological maturity. Two field experiments were conducted to evaluate chemical desiccation and panicle removal as methods for simulating the loss of carbohydrate production associated with leaf death or transport tissue damage when sorghum is exposed to freezing temperatures during grain fill. In one experiment, both treatments were repeated at 3- to 4-d intervals during grain fill with a range of hybrid maturities and environments to establish a relationship between caryopsis weight or test weight with heat unit accumulation after anthesis. This relationship was best described as sigmoidal in shape. A second field experiment compared these two treatments with potted field-grown plants exposed to -2° C for 4h. Treatments were applied four different times during grain fill. Panicle removal produced caryopsis weights 5% greater than those from freeze treatments, whereas chemical desiccation resulted in caryopsis weights 13% greater than those from freeze treatments. Test weights followed similar trends. Caryopsis weights from each treatment were similar across experiments. Panicle removal accurately simulated caryopsis weight reductions caused by exposure to freezing temperatures throughout the grain-filling period. Chemical desiccation underestimated freeze damage during early grain fill but adequately simulated caryopsis reductions during late grain fill. Test weights from panicle removal treatments were similar in both experiments, while chemical desiccation was inconsistent across experiments. Test weight reductions caused by exposure to freezing temperatures were not adequately simulated by either treatment. The results of these experiments indicate that panicle removal is a more appropriate method for simulating freeze damage to maturing grain sorghum than is chemical dessication; however, chemical desiccation may be utilized if appropriate adjustments are made during early grain fill.
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    Notes: Glycine max (L.) Merr.] fields in the Rolling Pampa, Argentina, to identify floristic and functional (life cycles, origin, and morphotypes) structure in fields with different management practices and to explore the association between weed species, cultural history, and crop yield. We surveyed 18 and 42 different fields in 1994 and 1995, respectively, in soybean cropped with conventional and no-tillage practices. In 1994, we recorded presence of weed species and in 1995 we recorded weed presence and abundance, and management information (type of tillage, number of agricultural cycles, grain yield, planting date, and weed control). We used multivariate analysis to examine relationships among variables. We distinguished four communities and eight floristic groups, related to crop yield and tillage system. The presence of Floristic Groups II [Oxalis chrysantha (Kunth) Prog., Sonchus oleraceus L., and Veronica persica Poir.], VII [Carduus acanthoides L., Stellaria media (L.) Vill., Physalis viscosa L., Taraxacum officinale Weber, and coronopus didymus (L.) Sm.], and IV [Bidens subalternans DC., Cirsium vulgare (Savi) Ten., and Cyperus sp.L.] may be an indicator of high potential crop yield (low soil degradation), and their absence may be an indicator of low potential crop yield (increasing soil degradation). Functional structure (life cycles, origin, and morphotypes) was similar between communities, indicating that agroecosystems preserve function, despite management practices. The main variables explaining weed distribution in the surveyed region were tillage system, crop yield, planting date, and the number of agricultural cycles.
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    Semigroup forum 91 (1999), S. 266-269 
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    Notes: Gossypium hirsutum L.). Rows were planted within a few centimeters of the rows from the previous year; a common practice in no-till agriculture. The selected soils were Memphis silt loam (fine-silty, mixed, active, thermic Typic Hapludalf), Lexington silt loam (fine-silty, mixed, Ultic Hapludalf), and Loring silt loam (fine-silty, mixed, active, thermic Oxyaquic Fragiudalf). Potassium rates of 0, 28, 56, and 112 kg ha-1 were broadcast annually beginning in 1991. Experimental design was a split plot with five replications. Samples were collected from individual plots in the planted row (IR) and between the row (BR) to a depth of 30 cm. The soil samples were divided into 0- to 8-cm, 8- to 15-cm, and 15- to 30-cm depths and Mehlich-1 P and K were evaluated. Mehlich-1 P varied with soils, sampling position, and soil depth. Differences in extractable P levels due to sampling position would not affect soil test ratings; however, additional years in no-till production may magnify position influences and so affect P fertilizer recommendation. Mehlich-1 K was greater for the IR sampling position of the 0- to 8-cm sampling depth for the three soils. Sampling only the BR position may in some instances give a lower soil test value, resulting in higher fertilizer applications. These differences varied with soil-applied K rates and may increase with additional time in no-till cotton.
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    Notes: Triticum aestivum L.) are maximized when the N supply contains a mixture of NH4 and NO3. Tillers per plant is the yield component most commonly increased by mixed N nutrition in greenhouse studies. The objective of this study was to evaluate, under field conditions, the response of 'Butte 86' spring wheat to N sources differing greatly in nitrification rate. Nitrogen was applied at 0 or 112 kg N ha-1; the N sources were calcium nitrate (CN), urea, urea-dicyandiamide (DCD), 0.1-g urea granules, and 0.1-g urea-DCD granules. Six field trials were performed. Topsoil (0-15 cm) analysis of fertilized plots during tillering indicated a wide range of mineral N contents (19-101 mg N kg-1) and of NH4;NO3 mole ratios (0.04-2.06). Correlation analyses suggested that tillering was sensitive to the total mineral N supply, but quite insensitive to the NH4;colon;NO3 ratio in the topsoil. Vegetative growth and N uptake were generally lower for CN than for the other N sources. At some locations, more heads per square meter at harvest were observed with the slower-nitrifying N sources. Grain yields were increased by N fertilization, but significant differences between N sources were not generally observed. For both years of the study, the 0.1-g urea-DCD granules gave the highest N uptake efficiency. However, the dramatic responses in growth, tillering, or grain yield routinely observed with mixed N nutrition in hydroponic or greenhouse studies could not be duplicated in the field.
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    Semigroup forum 91 (1999), S. 317-320 
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    Notes: pure error as variation between plots that are treated alike within a block. Within each location, each genotype was randomly assigned to two plots within each block of an RCB design. The pure error of soybean [Glycine max (L.) Merr.] genotypes was evaluated at eight locations. Our objective was to compare the block × treatment and pure error mean squares for yield, physiological maturity, and plant height to determine whether the NNA or UNADJ analysis reduces intrablock variation. The NNA analysis always decreased the magnitude of the block × treatment interaction mean squares, compared with the UNADJ analysis. In some comparisons, the pure error mean square of the NNA analysis was significantly smaller than the pure error of the UNADJ analysis. The magnitude of the block × treatment mean square is not useful for comparing the relative precision of these two analyses. When the pure error mean square was used to measure precision, the NNA was at least as precise as the UNADJ analysis.
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    Semigroup forum 91 (1999), S. 350-353 
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    Semigroup forum 91 (1999), S. 357-363 
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    Notes: Triticum aestivum L.; corn, Zea mays L.; rice, Oryza sativa L. and O. glaberrima Steud.; barley, Hordeum vulgare L.; sorghum, Sorghum bicolor (L.) Moench; millet, Pennisetum glaucum (L.) R. Br.; oat, Avena sativa L.; and rye, Secale cereale L.) is approximately 33%. The unaccounted 67% represents a $15.9 billion annual loss of N fertilizer (assuming fertilizer-soil equilibrium). Loss of fertilizer N results from gaseous plant emission, soil denitrification, surface runoff, volatilization, and leaching. Increased cereal NUE is unlikely, unless a systems approach is implemented that uses varieties with high harvest index, incorporated NH4-N fertilizer, application of prescribed rates consistent with in-field variability using sensor-based systems within production fields, low N rates applied at flowering, and forage productions systems. Furthermore, increased cereal NUE must accompany increased yields needed to feed a growing world population that has yet to benefit from the promise of N2-fixing cereal crops. The Consultative Group on International Agricultural Research (CGIAR) linked with advanced research programs at universities and research institutes is uniquely positioned to refine fertilizer N use in the world via the extension of improved NUE hybrids and cultivars and management practices in both the developed and developing world.
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    Semigroup forum 91 (1999), S. 457-463 
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    Notes: Medicago sativa L.) and Italian ryegrass (Lolium multiflorum Lam.) when treated with different types of mower-conditioners (rubber rolls; plastic or steel flails). Drying was measured by calculating the water loss rate from two subsequent hourly weights of swath portions placed on trays. Dry matter (DM) losses were estimated on 1.2-m lengths of swaths immediately after cutting. The steel flail conditioner provided faster drying than the other conditioning types for both crops. The effect of the rubber roll conditioner was limited due to the swath structure, especially with forage surface densities higher than 0.7 kg DM m-2. Tedding positively interacted with the conditioning treatment to increase the drying rate, especially when forage was conditioned with the rubber roll machine. Shatter losses from alfalfa were higher for the flail conditioner, ranging from 3.6 to 10.2%, and with greater loss of crude protein. The DM losses were always lower than 2.5% for Italian ryegrass. The most severe conditioning (steel flails) followed by tedding is appropriate for grass, as it significantly reduces the wilting time without affecting DM loss. However, a less severe conditioning (rubber rolls) without tedding is more appropriate for wilting alfalfa, to avoid excessive leaf and protein loss.
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    Notes: Sorghum bicolor (L.) Moench] for earlier harvest to preserve seed quality and quantity. Objectives of this study were (i) to examine the desiccant activity of glufosinate [2-amino-4-(hydroxy-methylphosphinyl)butanoic acid] applied at sever rates to grain sorghum at different seed moisture levels in contrasting environments and (ii) to determine the effect of glufosinate on germination and seedling growth of the treated crop. The soil at College Station (east-central Texas), was a Ships clay (very-fine, mixed, active, thermic, Chromic Hapludert); at Mayagüez, PR, a Coto clay (very-fine, kaolinitic, isohyperthermic Typic Hapludox). Glufosinate was evaluated because of its contact herbicidal properties and limited systemic activity. In both Texas and Puerto Rico, glufosinate was applied at 0, 0.56, 1.1, or 2.2 kg ha-1 to grain sorghum. Leaves and seed were sampled at 0, 1, 2, and 3 wk after treatment (WAT) for grain and leaf moisture. Seed was collected at 2 and 3 WAT for germination and growth studies. Glufosinate at all three treatment rates dried seed of the grain sorghum hybrid Atx638/Tx2783 in Texas from 〉 350 g kg-1 grain moisture at application to a storable moisture of 〈 120 g kg-1 at 2 WAT, at which time untreated grain moisture was 150 g kg-1. Glufosinate rate did not affect grain moisture except at the high glufosinate rate at 1 WAT. Leaf moisture reduction was glufosinate rate-dependent, but all treatments significantly reduced leaf moisture content at 1 WAT. Germination and seedling growth were not affected by glufosinate treatment. Grain desiccation rate under a tropical environment (Puerto Rico) was slightly slower than in Texas, but leaf moisture reduction was rapid and reached 〈 300 g kg-1 by 1 WAT from initial leaf moisture contents of 500 or 770 g kg-1. Germination was not adversely affected by glufosinate.
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    Semigroup forum 91 (1999), S. 426-431 
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    Notes: Solanum tuberosum L.). Root length density (RLD) and root dry matter production of potato were studied under two levels of supplemental irrigation (nonirrigated check vs. moderate irrigation) and two levels of soil amendments [none vs. amended with compost and manure from beef cattle (Bos taurus L.)] during 1993 and 1994. Amendments significantly increased RLD during both growing seasons and these increases occurred consistently throughout each growing season. Irrigation effects were not observed in 1993, while irrigation significantly increased RLD during 1994. Approximately 85% of the root length was concentrated in the upper 30-cm layer of the soil. The supplemental irrigation and soil amendment treatments did not affect the proportional distribution of roots among the soil layers. Root-to-root ratio was not affected by irrigation or amendment during either growing season. The RLD and leaf area index (LAI) at all four sample dates during 1994 were significantly correlated with final tuber yields, indicating that growth patterns early in the season were important in establishing the productivity of the potato crop. Root length density tended to have a higher correlation with yields than did LAI (r = 0.58* to 0.88** vs. 0.51* to 0.68**).
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    Topics: Mathematics
    Notes: Cichorium intybus L.; CHIC) as a component of hill-land pastures in Appalachia. In 1995, lamb (Ovis aries) gain was 56.1 kg ha-1 on orchardgrass (Dactylis glomerata L.; OG), while those grazing OG + CHIC lost 24.2 kg ha-1 during the 44-d midsummer grazing period (P 〈 0.05). In 1996, while weight gains were not different (P 〉 0.10), total lamb production per hectare was 14% less on OG + CHIC (258 kg ha-1) than on OG only (300 kg ha-1) for the 79-d grazing period. In 1997, total weight gained for the season was not different (P 〉 0.10); lambs grazed OG or CHIC for 110 d and production was 362 and 351 kg ha-1, respectively. Laboratory mixtures of 40∝60 or 60∝40 OG∝CHIC had higher (P & lt: 0.05) in vitro organic matter disappearance (IVOMD), compared with 100% OG or 100% CHIC. There was a synergism in mixtures with orchardgrass that increased IVOMD relative to pure samples. Another laboratory experiment suggested that as total N increased in chicory herbage, rate of in vitro neutral-detergent fiber (NDF) disappearance decreased. More information on the influence of soil type and management on chicory growth in pure stands and mixtures with other plant species is needed to optimize productivity of systems that include chicory.
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    Semigroup forum 91 (1999), S. 463-467 
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Hordeum vulgare L.) establishment on a water-repellent sand: (i) spraying various rates of banded (2 cm wide) wetting agent while furrow seeding with press wheels, (ii) seed placement either in a furrow or in the side of a ridge, and (iii) compaction with press wheels or a Flexi-Coil land packer. The application of wetting agent increased seedling emergence from 110 to 170 plants m-2, dry matter production from 4.2 to 6.0 t ha-1 and grain yield from 1.96 to 2.60 t ha-1, despite more weeds occurring with increasing rate of banded wetting agent. Use of press wheels, which also resulted in a furrow sowing condition, increased seedling emergence from 72 to 101 plants m-2 and grain yield from 1.70 to 2.13 t ha-1. In the absence of heavy press wheel compaction, furrow sowing at 18-cm row spacings with full soil disturbance had no effect on seedling emergence or grain yield. The application of wetting agent increased topsoil wetting. Increased soil wetting may have increased plant nutrient availability (from fertilizer and soil), reduced soil water evaporation, and possibly reduced water loss to subsoil on this duplex soil. The optimum degree of compaction required on water-repellent soils is not known and needs further research.
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    Semigroup forum 91 (1999), S. 631-636 
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Zea mays L.) under nonlimiting soil N conditions. Nitrate leaching has been identified as a source of non-point-source pollution. By identifying tillage practices which maximize corn N uptake, recommendations can be based on how to minimize N loss. A 2-yr field study was conducted in southwestern Quebec on a 2.4-ha site of a Typic Endoaquent (Humic Gleysol) cropped to corn. Three types of tillage practice (conventional tillage, reduced tillage, and no-till) were combined with two residue levels (with and without) in a randomized complete block design. The effect of these practices on corn yield and corn N were studied. Seedling emergence rates in spring, and corn moisture content at harvest, were also monitored. Residues hindered initial plant emergence in the no-till plots. Corn N and moisture contents in 1996 and 1997 indicated that no-till with residue had a delayed maturity relative to the other treatments. However, total corn biomass and grain yields were not affected by tillage or residue treatments. No correlation between corn yield and corn N content was found.
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    Semigroup forum 58 (1999), S. 85-93 
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
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    Semigroup forum 58 (1999), S. 106-125 
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Fa(x)=Fb(x) , for inverse semigroup varieties. In this paper, we give a complete analysis of all unary hyperiddentities for inverse semigroup varieties: for any such hyperidentity we describe the largest variety of inverse semigroups to satisfy it.
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    Semigroup forum 58 (1999), S. 190-206 
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
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    Semigroup forum 58 (1999), S. 241-247 
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: S be an infinite, discrete, cancellative semigroup and let BetaS be the Stone-Cech compactification of S. Then BetaS is a semigroup with an operation which extends that of S and which is continous only in one variable. We generalize some algebraic properties known to hold for the additive semigroup of the integers.
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