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  • Springer  (339,256)
  • 1995-1999  (339,256)
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Keywords
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Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    A constrained finite element method for modeling cloth deformation (1999)
    Springer
    The visual computer 15 (1999), S. 90-99 
    Details
    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
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003710050164
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  • 2
    Electronic Resource
    Electronic Resource
    Diffusive smoothing of polygonal meshes with bias and tension controls (1999)
    Springer
    The visual computer 15 (1999), S. 509-518 
    Details
    ISSN: 1432-2315
    Keywords: Key words: Smoothing – Diffusion systems – Bias and tension controls
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003710050196
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  • 3
    Electronic Resource
    Electronic Resource
    C2 Local convexity-preserving interpolation through the control point form method (1999)
    Springer
    The visual computer 15 (1999), S. 483-493 
    Details
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003710050194
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  • 4
    Electronic Resource
    Electronic Resource
    Comparison of antennal sensilla of Anaphes victus and A. listronoti (Hymenoptera, Mymaridae), egg parasitoids of Curculionidae (1999)
    Springer
    Zoomorphology 119 (1999), S. 1-8 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050076
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  • 5
    Electronic Resource
    Electronic Resource
    Morphology and morphometrics of the appendicular musculature in geckoes with different locomotor habits (Lepidosauria) (1999)
    Springer
    Zoomorphology 119 (1999), S. 9-22 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050077
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  • 6
    Electronic Resource
    Electronic Resource
    Larval and metamorphic skeletal development in the fast-developing frog Pyxicephalus adspersus (Anura, Ranidae) (1999)
    Springer
    Zoomorphology 119 (1999), S. 23-35 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050078
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  • 7
    Electronic Resource
    Electronic Resource
    CLSM analysis of development and structure of the central nervous system of Enchytraeus crypticus (”Oligochaeta”, Enchytraeidae) (1999)
    Springer
    Zoomorphology 119 (1999), S. 37-47 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050079
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  • 8
    Electronic Resource
    Electronic Resource
    Histochemical localization of FMRFamide, serotonin and catecholamines in embryonic Crepidula fornicata (Gastropoda, Prosobranchia) (1999)
    Springer
    Zoomorphology 119 (1999), S. 49-62 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050080
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  • 9
    Electronic Resource
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    Development of a unique eye: photoreceptors of the pelagic predator Atlanta peroni (Gastropoda, Heteropoda) (1999)
    Springer
    Zoomorphology 119 (1999), S. 81-91 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050083
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  • 10
    Electronic Resource
    Electronic Resource
    Evolution of the metathoracic tympanal ear and its mesothoracic homologue in the Macrolepidoptera (Insecta) (1999)
    Springer
    Zoomorphology 119 (1999), S. 93-103 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050084
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  • 11
    Electronic Resource
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    Fibre type regionalization of forelimb muscles in two mammalian species, Galea musteloides (Rodentia, Caviidae) and Tupaia belangeri (Scandentia, Tupaiidae), with comments on postnatal myogenesis (1999)
    Springer
    Zoomorphology 119 (1999), S. 117-126 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    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).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050086
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  • 12
    Electronic Resource
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    Ultrastructure of spermiogenesis and spermatozoa in Bradynectes sterreri and remarks on sperm cells in Haplopharynx rostratus and Paromalostomum fusculum: phylogenetic implications for the Macrostomorpha (Plathelminthes) (1999)
    Springer
    Zoomorphology 119 (1999), S. 105-115 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050085
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  • 13
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    Functional morphology of musculature in the acoelomate worm, Convoluta pulchra (Plathelminthes) (1999)
    Springer
    Zoomorphology 119 (1999), S. 127-142 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050087
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  • 14
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    The adhesive devices in larvae of Lepidoptera (Insecta, Pterygota) (1999)
    Springer
    Zoomorphology 119 (1999), S. 143-162 
    Details
    ISSN: 1432-234X
    Keywords: Abbreviations L1, L2, L3: instars of larvae ; Lm: mature larva(e)
    Source: Springer Online Journal Archives 1860-2000
    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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    URL: http://dx.doi.org/10.1007/s004350050088
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  • 15
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    Comparative morphology of tergal phragmata occurring in the dorsal thoraco-abdominal junction of ditrysian Lepidoptera (Insecta) (1999)
    Springer
    Zoomorphology 119 (1999), S. 163-183 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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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    URL: http://dx.doi.org/10.1007/s004350050089
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  • 16
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    Functional morphology of the ovipositor in Megarhyssa atrata (Hymenoptera, Ichneumonidae) and its penetration into wood (1999)
    Springer
    Zoomorphology 119 (1999), S. 73-79 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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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    URL: http://dx.doi.org/10.1007/s004350050082
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  • 17
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    Stellate cells in the Malpighian tubules of Drosophila hydei and D. melanogaster larvae (Insecta, Diptera) (1999)
    Springer
    Zoomorphology 119 (1999), S. 63-71 
    Details
    ISSN: 1432-234X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    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).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004350050081
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  • 18
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    Periodic points for actions of tori in Stein manifolds (1999)
    Springer
    Mathematische Annalen 314 (1999), S. 39-52 
    Details
    ISSN: 1432-1807
    Keywords: Mathematics Subject Classification (1991):32M05, 32S20, 32A27, 58F08
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002080050285
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  • 19
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    Involutions on moduli spaces and refinements of the Verlinde formula (1999)
    Springer
    Mathematische Annalen 314 (1999), S. 291-326 
    Details
    ISSN: 1432-1807
    Keywords: Mathematics Subject Classification (1991):14H60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002080050296
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  • 20
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    Dynamics of polynomial skew products on ${\bf C}^2$ (1999)
    Springer
    Mathematische Annalen 314 (1999), S. 403-447 
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    ISSN: 1432-1807
    Keywords: Mathematics Subject Classification (1991):32H50, 58F23, 58F15
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    Topics: Mathematics
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    URL: http://dx.doi.org/10.1007/s002080050301
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    The Weierstrass approximation theorem for maps between real algebraic varieties (1999)
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    Mathematische Annalen 314 (1999), S. 601-612 
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    ISSN: 1432-1807
    Keywords: Mathematics Subject Classification (1991):14P05, 14P25
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    Topics: Mathematics
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    Zeros of Eisenstein series, quadratic class numbers and supersingularity for rational function fields (1999)
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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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    URL: http://dx.doi.org/10.1007/s002080050291
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    Commutative subrings of certain non-associative rings (1999)
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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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    URL: http://dx.doi.org/10.1007/s002080050294
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    Topological entropy in exact $C^*$ -algebras (1999)
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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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    URL: http://dx.doi.org/10.1007/s002080050298
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    Noncommutative algebraic models for fiber squares (1999)
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    Mathematische Annalen 314 (1999), S. 449-467 
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    ISSN: 1432-1807
    Keywords: Mathematics Subject Classification (1991):18G55, 55P99, 55R05, 55R20, 55T20, 55U35, 57T30, 57T35
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    Topics: Mathematics
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    URL: http://dx.doi.org/10.1007/s002080050302
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    Operations on locally free classgroups (1999)
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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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    URL: http://dx.doi.org/10.1007/s002080050312
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    DNA conformation and dynamics (1999)
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    Radiation and environmental biophysics 38 (1999), S. 23-29 
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    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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    3rd Annual Meeting of the German Society for Biological Radiation Research (Gesellschaft für Biologische Strahlenforschung) (1999)
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    Radiation and environmental biophysics 38 (1999), S. 72-72 
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    URL: http://dx.doi.org/10.1007/s004110050139
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    Formation of single- and double-strand breaks of pBR322 plasmid irradiated in the presence of scavengers (1999)
    Springer
    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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    Repair of cellular radiation damage in space under microgravity conditions (1999)
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    Radiation and environmental biophysics 38 (1999), S. 133-138 
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    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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    The track structures of ionizing particles and their application to radiation biophysics (1999)
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    Radiation and environmental biophysics 38 (1999), S. 175-184 
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    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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    Practical aspects of Monte Carlo simulation of charged particle transport: Mixed algorithms and variance reduction techniques (1999)
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    Radiation and environmental biophysics 38 (1999), S. 15-22 
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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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    Synthetic activity of rat blood lymphocytes under acute and continuous gamma-irradiation – fluorescent microspectral study (1999)
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    Radiation and environmental biophysics 38 (1999), S. 49-56 
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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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    Radon-induced lung cancer in smokers and non-smokers: risk implications using a two-mutation carcinogenesis model (1999)
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    Radiation and environmental biophysics 38 (1999), S. 57-71 
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    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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    A Monte Carlo code for positive ion track simulation (1999)
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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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    Biological effects of ion beams in Nicotiana tabacum L. (1999)
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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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    Condensed-history Monte-Carlo simulation for charged particles: what can it do for us? (1999)
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    Radiation and environmental biophysics 38 (1999), S. 163-173 
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    ISSN: 1432-2099
    Keywords: Key words Charged particles ; Electron transport scheme ; Microdosimetry ; Monte Carlo simulation ; Radiation dosimetry ; Radiotherapy ; Track structure
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    Topics: Biology , Physics
    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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    Estimation of the target stem-cell population size in chronic myeloid leukemogenesis (1999)
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    Radiation and environmental biophysics 38 (1999), S. 201-206 
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    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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    Topics: Biology , Physics
    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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    Announcement (1999)
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    Radiation and environmental biophysics 38 (1999), S. 219-219 
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    Tumor therapy and track structure (1999)
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    Radiation and environmental biophysics 38 (1999), S. 229-237 
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    Keywords: Key words Ions ; Tumor therapy ; RBE ; Track structure ; Treatment planning ; Carbon beam
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    Topics: Biology , Physics
    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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    Effect of lithium on thyroidal 131iodine uptake, its clearance, and circulating levels of triiodothyronine and thyroxine in lead-treated rats (1999)
    Springer
    Radiation and environmental biophysics 38 (1999), S. 261-266 
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    ISSN: 1432-2099
    Keywords: Key words Iodine uptake ; Lead ; Lithium ; Rats ; Thyroid ; Thyroid hormones
    Source: Springer Online Journal Archives 1860-2000
    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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    A Parametric Estimation Approach for Groove Dimensioning Using Remote Field Eddy Current Inspection (1999)
    Springer
    Research in nondestructive evaluation 11 (1999), S. 39-57 
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    ISSN: 1432-2110
    Source: Springer Online Journal Archives 1860-2000
    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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    Nondestructive Evaluation of Microcracks in Ceramics with Controlled Probability of False Alarm (1999)
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    Research in nondestructive evaluation 11 (1999), S. 15-24 
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    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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    Nondestructive Determination of the Elastic Anisotropy in Aluminum—SiC and —Al 2 O 3 Metal—Matrix Composites (1999)
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    Research in nondestructive evaluation 11 (1999), S. 1-13 
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    ISSN: 1432-2110
    Source: Springer Online Journal Archives 1860-2000
    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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    Nondestructive Characterization of Adhesive Joint Durability Using Ultrasonic Reflection Measurements (1999)
    Springer
    Research in nondestructive evaluation 11 (1999), S. 81-95 
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    ISSN: 1432-2110
    Source: Springer Online Journal Archives 1860-2000
    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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    Ultrasonic Wave Scattering by a Line Crack in a Solder Joint (1999)
    Springer
    Research in nondestructive evaluation 11 (1999), S. 117-135 
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    ISSN: 1432-2110
    Source: Springer Online Journal Archives 1860-2000
    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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    Practical Shear Wave Lens Design for Improved Resolution with Acoustic Microscope (1999)
    Springer
    Research in nondestructive evaluation 11 (1999), S. 97-116 
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    ISSN: 1432-2110
    Source: Springer Online Journal Archives 1860-2000
    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 Varieties and Semigroup Algebras (1999)
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    Semigroup forum 59 (1999), S. 461-466 
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    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
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    On Existence Varieties of E-solid Semigroups (1999)
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    Semigroup forum 59 (1999), S. 470-521 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    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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    On equalizer-flat acts (1999)
    Springer
    Semigroup forum 58 (1999), S. 5-16 
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    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    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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    On existence varieties of E-solid semigroups (1999)
    Springer
    Semigroup forum 58 (1999), S. 17-68 
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    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    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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    Transitive actions of semigroups in semi-simple Lie groups (1999)
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    Semigroup forum 58 (1999), S. 142-151 
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    Topics: Mathematics
    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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    Fundamentals of Semigroup Theory by John M. Howie (1999)
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    Semigroup forum 58 (1999), S. 156-158 
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    Spectral theory and generator property for one-sided coupled operator matrices (1999)
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    Semigroup forum 58 (1999), S. 267-295 
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    Topics: Mathematics
    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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    Representation of Finite Lattices by Annihilators of Completely 0-Simple Semigroups (1999)
    Springer
    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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    Are Simulation Models Ready for Agricultural Research in Developing Countries? (1999)
    Springer
    Semigroup forum 91 (1999), S. 1-4 
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    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    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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    Conservation Tillage Corn Production for a Semiarid, Subtropical Environment (1999)
    Springer
    Semigroup forum 91 (1999), S. 116-121 
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    Topics: Mathematics
    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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    Acidic Soil Amendment with a Magnesium-Containing Fluidized Bed Combustion By-Product (1999)
    Springer
    Semigroup forum 91 (1999), S. 24-32 
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    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    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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    Methods of Simulating Freezing Damage during Sorghum Grain Fill (1999)
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    Semigroup forum 91 (1999), S. 46-53 
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    Topics: Mathematics
    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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    Soybean Weed Communities: Relationships with Cultural History and Crop Yield (1999)
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    Semigroup forum 91 (1999), S. 234-241 
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    Topics: Mathematics
    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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    Vertical Phosphorus and Potassium Stratification in No-Till Cotton Soils (1999)
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    Semigroup forum 91 (1999), S. 266-269 
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    Topics: Mathematics
    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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    Response of Spring Wheat to Nitrogen Fertilizers of Different Nitrification Rates (1999)
    Springer
    Semigroup forum 91 (1999), S. 287-293 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    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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    Intrablock Variance among Duplicate Treatments for Nearest-Neighbor Analyses (1999)
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    Semigroup forum 91 (1999), S. 317-320 
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    Topics: Mathematics
    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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    Fertility Gradients in Naturally Formed Terraces on Honduran Hillside Farms (1999)
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    Semigroup forum 91 (1999), S. 350-353 
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    Improving Nitrogen Use Efficiency for Cereal Production (1999)
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    Semigroup forum 91 (1999), S. 357-363 
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    Topics: Mathematics
    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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    Effects of Mechanical Conditioning on Wilting of Alfalfa and Italian Ryegrass for Ensiling (1999)
    Springer
    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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    Desiccation and Germination of Grain Sorghum As Affected by Glufosinate (1999)
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    Semigroup forum 91 (1999), S. 373-376 
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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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    Soil Management and Supplemental Irrigation Effects on Potato: II. Root Growth (1999)
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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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    Chicory Effects on Lamb Weight Gain and Rate of In Vitro Organic Matter and Fiber Disappearance (1999)
    Springer
    Semigroup forum 91 (1999), S. 445-450 
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    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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    Banded Wetting Agent and Compaction Improve Barley Production on a Water-Repellent Sand (1999)
    Springer
    Semigroup forum 91 (1999), S. 463-467 
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    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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    Yield and Nitrogen Content of Corn under Different Tillage Practices (1999)
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    Semigroup forum 91 (1999), S. 631-636 
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    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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    Generalization of the d'Alembert formula and the Fourier method (1999)
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    Semigroup forum 58 (1999), S. 85-93 
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    Unary hyperidentities for varieties of inverse semigroups (1999)
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    Semigroup forum 58 (1999), S. 106-125 
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    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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    The monoid of orientation-preserving mappings on a chain (1999)
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    Semigroup forum 58 (1999), S. 190-206 
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    On the semigroup BetaS (1999)
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    Semigroup forum 58 (1999), S. 241-247 
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    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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    On Radical Congruence Systems (1999)
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    Semigroup forum 59 (1999), S. 56-73 
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    On Radicals of Semigroup Algebras (1999)
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    Semigroup forum 59 (1999), S. 93-105 
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    Notes: p -separative semigroups. In particular, the coincidence of the Jacobson radical and the Baer radical of a nilpotent group algebra over a field of prime characteristic is established.
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    Random Partitions by Semigroup Methods (1999)
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    Semigroup forum 59 (1999), S. 126-140 
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    Notes: P of all partitions of {1,2,3,...}, or rather its distribution. There is a natural compact metrizable topology on P taking care of measurability questions. With respect to the maximum operation P becomes an abelian semigroup, and our first theorem characterizes random partitions as normalized positive definite functions on the subsemigroup of partitions "with finite support". We then present a new proof of Kingman's theorem stating that the exchangeable random partitions form a simplex whose extreme points are the so-called "paint-box distributions". An interesting moment problem which is still open arises in this connection.
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    The Endomorphism Structure of Simple Faithful S-acts (1999)
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    Semigroup forum 59 (1999), S. 179-182 
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    Extending Ideals in Regular Topological Semigroups (1999)
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    Semigroup forum 59 (1999), S. 175-178 
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    Combinatorially Factorizable Inverse Monoids (1999)
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    Semigroup forum 59 (1999), S. 220-232 
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    On the Finite Basis Problem for Completely 0-Simple Semigroup Identities (1999)
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    Semigroup forum 59 (1999), S. 197-219 
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    Certain Relations on the Congruence Lattice of a Completely Regular Semigroup (1999)
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    Semigroup forum 59 (1999), S. 264-281 
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    Book Review: Algebra in the Stone-Cech Compactification by Neil Hindman and Dona Strauss (De Gruyter Expositions in Mathematics 27, de Gruyter, Berlin, New York, 1998, xiii + 485 pp. ISBN 3-11-015420-X) (1999)
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    Semigroup forum 59 (1999), S. 310-314 
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    Principal-ideal Bands (1999)
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    Semigroup forum 59 (1999), S. 362-373 
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    Norm Discontinuity of Ornstein-Uhlenbeck Semigroups (1999)
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    Semigroup forum 59 (1999), S. 389-403 
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    Topological Properties of Inverse Limits of Free Abelian Monoids, with an Application to Inverse Limits of UFDs (1999)
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    Semigroup forum 59 (1999), S. 418-434 
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    Möbius Type Semigroups in SL(2,F) (1999)
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    Semigroup forum 59 (1999), S. 453-460 
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    Notes: F with an order P, the semigroup S of elements in SL(2,F) having entries in P can be factored into upper triangular, diagonal and lower triangular matrices. Moreover, we show that the semigroup ±S is maximal in SL(2,F).
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    Red Clover and Tillage Influence on Soil Temperature, Water Content, and Corn Emergence (1999)
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    Semigroup forum 91 (1999), S. 101-108 
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    Notes: Zea mays L.) because of problems with excess water, lower temperatures, and residue management during the early stages of corn growth. This is a problem, as corn is commonly used in rotation with wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr.]. Furthermore, when corn follows winter wheat there may be additional problems associated with residue management during the early stages of corn growth. Hence, the objectives of this study were to measure the effect of the red clover (Trifolium pratense L.) cover crop underseeded in wheat and no-tillage on soil temperature, water content, corn emergence, surface residue, and yields in a wheat-corn-soybean rotation in southwestern Ontario. Treatments included conventional vs. no-tillage both with and without underseeded red clover in a wheat-corn-soybean rotation in a clay loam soil. A no-tillage and red clover treatment that had the wheat straw baled was also included. No-tillage (with and without red clover) increased soil water content by 2 to 5% and reduced soil temperatures by 1 to 2°C during early corn emergence. Soil drying occurred along the planting slot of the no-tillage treatments, which enabled the soil seed furrow to open and the corn seedlings to become water stressed even though the no-tillage treatments were wetter in the spring. Corn emergence in the no-tillage treatment without red clover was delayed by 3 to 4 d and the final plant stand was reduced by 24% compared with the conventional tillage treatment. The no-tillage treatment without red clover had 13% lower corn grain yield than the conventional tillage treatment averaged over three years. However, when red clover was included with no-tillage, corn emergence was increased and corn grain yields were not significantly different from conventional tillage in both 1994 and 1996. There was also 15% less dry weight of surface plant residue present in the no-tillage treatments when red clover was included. Hence, red clover alleviated some of the problems of no-tillage for corn production.
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    Plant Determinants of Mycorrhizal Dependency in Soybean (1999)
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    Semigroup forum 91 (1999), S. 135-141 
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    Notes: Glycine soja Sieb. & Zucc. PI 468916; referred to hereafter as Soja), to intermediate [Glycine max (L.) Merr. cv. Mandarin] and low (G. max cv. Swift). Shoot weight, P percentage in shoot tissue, total shoot P uptake, P use efficiency, rate of growth, and root acid phosphatase activity were measured at three harvests when plants were grown at three relative P levels, each with and without mycorrhizal fungal (Gigaspora margarita Becker & Hall) colonization. Soja developed an active symbiosis more quickly than Swift or Mandarin, and mycorrhizae clearly aided in P uptake. When averaged across harvests at low P, mycorrhizal Soja had 7.8 times greater total shoot P than nonmycorrhizal Soja. Comparable values were 2.4 for Mandarin and 1.5 for Swift. Soja roots showed higher phosphatase activity and a higher percentage increase in phosphatase activity with mycorrhizal colonization than did the other two cultivars. Nonmycorrhizal Soja root lengths (avg. 1401 cm) at 5-wk growth were significantly shorter than Mandarin (2303 cm) and Swift (2236 cm) root lengths. The mean diameter of lateral roots of Soja (0.38 mm) was greater than that of Mandarin or Swift (≈ 0.26 mm). Root lengths and root surface areas were negatively correlated (P 〈 0.01) with MD.
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    Evaluation of Fine Root Length and Diameter Measurements Obtained Using RHIZO Image Analysis (1999)
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    Semigroup forum 91 (1999), S. 142-147 
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    Notes: -2 . For samples with higher values, however, the method underestimated total length by 〉5%. It is therefore recommended that users of image analysis systems determine this maximum length per unit area for accurate determinations of total root length. In samples that contained different string diameters, the total sample length and average string diameter could accurately be measured. However, the length per diameter class was underestimated by 〉20% when the string diameter was less than one pixel smaller than the upper limit of the diameter class. Adjustment of diameter intervals and increasing the scanner resolution are required to reduce this underestimation. Both the length and the angle of the short segments analyzed were found to influence diameter measurement. Similar sets of experiments are proposed for a rigorous evaluation of the performance of other image analysis systems on root measurements.
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    Soil Nitrate Accumulation and Corn Response to Preceding Small-Grain Fertilization and Cover Crops (1999)
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    Semigroup forum 91 (1999), S. 17-24 
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    Notes: 3 leaching risk and lower fertilizer N requirements for succeeding crops, will be fully realized only when the cover crop N contribution is accurately accounted for and availability is synchronous with succeeding crop N demands. The objectives of this study were to evaluate spring soil NO3-N accumulation patterns and N availability to corn (Zea mays L.) following annual ryegrass (Lolium multiflorum L.), oilseed radish [Raphanus sativus (L.) var. oleiferus (Stokes) Metzg.], red clover (Trifolium pratense L.), and no cover crop established after either winter wheat (Triticum aestivum L.) or barley (Hordeum vulgare L.). The wheat and barley were produced with 0.5, 1.0, and 2.0 times the amount of recommended N fertilizer. Six field trials were conducted on well-drained Typic Hapludalf soils in southwestern Ontario intermittently from 1989 to 1995. Corn was produced using a spring mulch-till system with only 10 kg ha-1 of fertilizer N, which was applied as part of the P starter fertilizer. Applying more fertilizer N to the previous year's small-grain crop rarely increased spring soil NO3-N concentrations or corn yields. Soil NO3-N concentration increases between the May and June sample dates following annual ryegrass and oilseed radish did not differ substantially from where a cover crop had not been established; following red clover, however, NO3-N increases were always at least 2.8 times greater than after no cover crop. Average aboveground corn biomass N at anthesis following annual ryegrass was 25.6 kg ha-1 less than when no cover crop was grown, whereas following red clover it was 40.4 kg ha-1 greater than with no cover crop. Corn yields were consistently the highest following red clover and often the lowest following annual ryegrass; yield response was positively correlated with June soil NO3-N concentrations (r= 0.61-0.93). These results suggest that N availability to succeeding corn differs among the cover crop treatments evaluated in the order red clover 〉 oilseed radish ≥ no cover crop 〉 annual ryegrass.
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    Harvest Management of Switchgrass for Biomass Feedstock and Forage Production (1999)
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    Semigroup forum 91 (1999), S. 5-10 
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    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Panicum virgatum L.), a warm-season perennial grass native to North America, has potential as a biomass energy crop. Our objective was to develop harvest management recommendations for biomass feedstock and forage production. 'Alamo' switchgrass was established in 1992 at Stephenville and Dallas, TX. Four harvest frequencies (one to four cuts per year) and three final autumn harvests (Sept., Oct., or Nov.) were imposed from 1993 to 1996. Tiller densities were counted each spring. Neutral detergent fiber (NDF) and crude protein (CP) concentrations were measured in 1993 and 1994. Concentrations of NDF were lowest (avg. = 640 g kg-1) and of CP (avg. = 110 g kg-1) were highest in May-harvested biomass. Forage quality of regrowth decreased with age, reaching NDF concentrations of 790 g kg-1 and CP of 〈20 g kg-1. Total seasonal yields decreased as harvest frequency increased; however, a severe drought reversed this trend at Dallas in 1996. The highest yields (15-20 Mg ha-1) occurred with a single harvest in mid-September. Delaying the final harvest until November reduced yields. Harvest date and frequency did not affect tiller density, although tiller density decreased from 900 to 650 and 630 to 310 m-2 at Dallas and Stephenville, respectively, during 1994 to 1997. Thus, a single mid-September harvest should maximize biomass yields in the south-central USA〉 A two-cut (spring-autumn) system may allow a farmer to use initial growth as forage and the regrowth for biomass, but total yields would be reduced. More frequent harvests would reduce yields further.
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  • 94
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    Spatial Variation Affects Precision of Perennial Cool-Season Forage Grass Trials (1999)
    Springer
    Semigroup forum 91 (1999), S. 75-81 
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    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Dactylis glomerata L.), ryegrasses [a group comprising perennial ryegrass, Lolium perenne L.; intermediate ryegrass, L. hybridum Hausskn.; and festulolium, ×Festulolium braunii (K. Richt.) A. Camus], smooth bromegrass (Bromus inermis Leyss.), reed canarygrass (Phalaris arundinacea L.), tall fescue (Festuca arundinacea Schreb.), and timothy (Phleum pratense L.). Dry matter forage yield was determined for 3 yr on each trial and expressed, for each plot, as mean annual yield. Yield data for each trial were analyzed by the RCB or lattice model, trend analysis, and two NNA models (one or two covariates). Three incremental improvements in precision of entry means were observed: an average of 15% due to the RCB design, an additional average of 17% due to the lattice design, and an additional average of 22 to 30% due to trend analysis or NNA. Trials were highly variable in the relative efficiency of both their experimental design and the spatial analyses, but this variability was not related to species, planting years, or plot size. The only useful predictor of trial efficiency was number of entries: three of five trials with eight or fewer entries failed to show significant differences among entries, regardless of the analysis. Spatial analysis methods cannot overcome lack of true differences among entries or failure to detect differences due to low degrees of freedom. Trend analysis of NNA appear to be useful mechanisms to account for intrablock variability in fields where it is impossible or uneconomical to predict proper blocking patterns.
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  • 95
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    Performance of Sweet and Forage Sorghum Grown Continuously, Double-Cropped with Winter Rye, or in Rotation with Soybean and Maize (1999)
    Springer
    Semigroup forum 91 (1999), S. 93-101 
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    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Sorghum bicolor (L.) Moench] with winter rye (Secale cereale L.) could increase annual dry matter production in the North-Central region of the USA and reduce soil erosion and other environmental concerns. We conducted this study to compare yield, chemical composition, erosion potential, and economics of sorghum grown continuously (sole crop), in a 3-yr rotation with maize (Zea mays L.) and soybean [Glycine max (L.) Merr.], or double-cropped with winter rye (rye-sorghum). The experiment was on a Typic Calciaquoll soil in central Iowa with 2 to 7% slope. Applied N moderately affected sole-cropped sorghum, with yields of 13.5, 16.1, 16.9, and 15.9 t ha-1 when fertilized with 0, 70, 140, and 280 kg ha-1 N, respectively. Rye-sorghum was highly responsive to N, with combined yields at 72, 84, 95, and 110% of sole-cropped sorghum fertilized with the same annual rate of N. Drought dramatically reduced rye-sorghum yields. Sole-cropped sweet sorghum had yields similar to sweet sorghum grown in the 3-yr rotation. Environmental conditions associated with years and locations affected fiber components N, and total nonstructural carbohydrate concentrations of sorghum. Use of the Universal Soil Loss Equation revealed that planting rye before sorghum would reduce estimated soil loss at both locations, but the loss was still unacceptably high on the sloping soil in southern Iowa (22 t ha-1). An economic partial budget showed that rye-sorghum cost $147 ha-1 more to produce than sole-cropped sorghum. We conclude that, if winter rye is to be grown as a double crop with sorghum in the North-Central region, it will likely be because of its positive influence on the environment and not because of potential for improved yield.
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  • 96
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    Evaluation of the Root Zone Water Quality Model Using Field-Measured Data from the Missouri MSEA (1999)
    Springer
    Semigroup forum 91 (1999), S. 183-192 
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    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Zea mays L.) and soybean [Glycine max (L.) Merr.] yield predictions were within 15 and 20%, respectively, of those measured. Using the macropore option, (constant cracking) greatly improved the prediction of chemical losses to seepage. Annual runoff simulated for corn and soybean under conventional and no-till systems was adequately predicted. The model underpredicted large runoff events and overpredicted runoff events that occurred after long dry periods when soil cracking was a dominant factor. The model overpredicted NO- 3N concentrations in runoff but underpredicted concentrations in near-surface soils. Predicted and measured atrazine [6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine] and alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide) concentrations in surface runoff compared well, particularly when the computed runoff was close to that measured. In this study, the model was run using the option of constant cracking in the soil. To improve the predictions of agrichemical losses to runoff and seepage, RZWQM should include the capability to predict variable soil cracking based on soil moisture.
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  • 97
    Electronic Resource
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    Plant Production Model Evaluation for the Root Zone Water Quality Model (RZWQM 3.2) in Ohio (1999)
    Springer
    Semigroup forum 91 (1999), S. 220-227 
    Details
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Zea mays L.) and soybean [Glycine max (L.) Merr.] biomass data collected at the Ohio MSEA from 1991 to 1993 were used for evaluation. Data from 1992 were used in calibrating RZWQM, and data from two other years (1991 and 1993) at the same site were used for validation. Crop growth predictions were compared with observed values of leaf, stem, and seed biomass collected throughout the growing season. Leaf and stem biomass predictions generally fell within 1 SD of the observed values, but for all years there were dates when predictions were outside of the observed range. RZWQM predicted seed biomass or yield adequately for all 3 years, with predictions falling within 1 SD of the observed values. Soil water content estimates for corn were higher than observed values late in the season, perhaps because of underestimates of evapotranspiration due to errors in leaf area predictions. The model overpredicted nitrate concentrations for the corn plot late in the season. Nitrate concentrations for the soybean plot were generally underpredicted. These differences may be due to underestimates of the fast humus pool of the nutrient model and of the N2 fixation rate for soybean. More evaluation is needed to refine the nitrate and soil water content predictions.
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  • 98
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    Testing CERES-Wheat with Free-Air Carbon Dioxide Enrichment (FACE) Experiment Data: CO2 and Water Interactions (1999)
    Springer
    Semigroup forum 91 (1999), S. 247-255 
    Details
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: 2 concentration and associated climate change on crop yields. Such model predictions are largely untested in the field, for lack of experimental data. We tested the CERES-Wheat model, modified to include leaf-level photosynthesis response to elevated CO2 using field data from 2 yr of Free-Air Carbon Dioxide Enrichment (FACE) experiments with spring wheat (Triticum aestivum L. cv. Yecora Rojo) in Maricopa, AZ. Two irrigation treatments (well-watered, WW; water-deficit stressed, WS) and two atmospheric CO2 concentrations (ambient, 350 μmol mol-1, elevated, 550 μmol mol-1) were simulated. The model was evaluated using measurements of crop phenology, aboveground dry matter (DM) production, grain yield, and evapotranspiration (ET). Model calculations of crop phenology were within 2 to 3 d of observed values under WW, ambient CO2 conditions in both years. The model did not simulate the accelerated crop phenology (5-8 d at physiological maturity) observed in the WW and elevated CO2 treatments, indicating the need to include effects of increased stomatal resistance on canopy temperature. Simulations of DM and grain yield were within 10% of measured values, except for a tendency to overcalculate DM response to CO2 by 10 to 15% in Year 1 for WS treatments. The model undercalculated cumulative ET under WW conditions by 15%; model sensitivity analyses suggest that simulation of potential evapotranspiration (PET) was too low for this arid site. The model reproduced measured dynamics of CO2-water interactions. Simulated reductions in water loss due to elevated CO2 were about 4%, in agreement with measurements. The model simulated larger increases in DM production and yield due to elevated CO2 under WS than under WW conditions. In Year 1, simulated crop response to CO2 was 2% larger (measured:3%) under WS than under WW conditions; in Year 2, it was 11% larger (measured: to be further evaluated with additional experimental datasets, is an important attribute of models used to project crop yields under elevated CO2 and climate change.
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  • 99
    Electronic Resource
    Electronic Resource
    Soil Organic Matter and Wheat Productivity in the Semiarid Argentine Pampas (1999)
    Springer
    Semigroup forum 91 (1999), S. 276-279 
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    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Triticum aestivum L.) yields in response to SOM levels and related properties and to quantify the contribution of a unit increment of SOM content to soil productivity during 1991, 1992, and 1994 on a total of 134 production fields in the semiarid Argentine Pampas. Wheat yields were related to both soil water retention and total organic (TOC) contents in the top layers (0-20 cm) in years with low moisture availability (1992 [r= 0.51, P 〈0.01] and 1994 [r = 0.59, P 〈 0.01]), and were related to both total N and available P contents in a year without water deficit stress (1991 [r = 0.58, P 〈 0.01]). Wheat yields over all years were linearly related to TOC (r = 0.68, P 〈 0.01) when these contents were 〈17.5 g kg-1. Dependence of wheat yields on soil water retention and on TOC contents under water deficit was related to the positive effect of these soil components on plant-available water. In the absence of water deficit (1991), nutrient availability was the limiting factor. Losses of 1 Mg SOM ha-1 were associated with a decrease in wheat yield of approximately 40 kg ha-1. These results demonstrate the importance of using cultural practices that minimize losses of soil organic C in the semiarid Argentine Pampas.
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  • 100
    Electronic Resource
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    Remobilization of Pre-Anthesis Assimilates to the Grain for Grain Only and Dual-Purpose (Forage and Grain) Triticale (1999)
    Springer
    Semigroup forum 91 (1999), S. 312-316 
    Details
    ISSN: 1432-2137
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Triticosecale Wittmack). Field experiments were conducted in 1992 and 1993 in northeastern Spain. Two harvesting treatments were used: (i) grain production only and (ii) cutting the crop for forage at the beginning of jointing and harvesting the grain produced after regrowth. Pre-anthesis storage of carbohydrates was very important to grain filling in triticale, both for grain and for dual-purpose. Contribution of pre-anthesis assimilates to grain yield in the uncut plots was 46% in spring triticale genotypes and 65% in winter genotypes, as the later-maturity winter triticale genotypes were more affected by terminal abiotic stresses. Reductions in DM accumulated at anthesis after forage removal were more pronounced in winter genotypes (39%) than in spring genotypes (20%), where an earlier development allowed for a longer recovery period after cutting; DM reductions were similar to grain yield decreases. The effect of forage removal on translocation depended on the growth habit of the genotype and environmental conditions. Most differences were associated with changes in crop phenology. In spring types, with early jointing, DM translocation and the contribution of pre-anthesis assimilates to grain were not affected by forage removal, whereas both traits were drastically reduced in winter triticale. Most differences in 13C/12C carbon isotope discrimination (δ) in grains were also phenology driven.
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