bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pit Membrane Porosity and Water Stress-Induced Cavitation in Four Co-Existing Dry Rainforest Tree Species
Authors: Choat Brendan , Ball Marilyn , Luly Jon , Holtum Joseph 
Published: January 2003

Abstract
Aspects of xylem anatomy and vulnerability to water stress-induced embolism were examined in stems of two drought-deciduous species, Brachychiton australis (Schott and Endl.) A. Terracc. and Cochlospermum gillivraei Benth., and two evergreen species, Alphitonia excelsa (Fenzal) Benth. and Austromyrtus bidwillii (Benth.) Burret., growing in a seasonally dry rainforest. The deciduous species were more vulnerable to water stress-induced xylem embolism. B. australis andC. gillivraei reached a 50% loss of hydraulic conductivity at −3.17 MPa and −1.44 MPa, respectively; a 50% loss of hydraulic conductivity occurred at −5.56 MPa in A. excelsa and −5.12 MPa in A. bidwillii. To determine whether pit membrane porosity was responsible for greater vulnerability to embolism (air seeding hypothesis), pit membrane structure was examined. Expected pore sizes were calculated from vulnerability curves; however, the predicted inter-specific variation in pore sizes was not detected using scanning electron microscopy (pores were not visible to a resolution of 20 nm). Suspensions of colloidal gold particles were then perfused through branch sections. These experiments indicated that pit membrane pores were between 5 and 20 nm in diameter in all four species. The results may be explained by three possibilities: (a) the pores of the expected size range were not present, (b) larger pores, within the size range to cause air seeding, were present but were rare enough to avoid detection, or (c) pore sizes in the expected range only develop while the membrane is under mechanical stress (during air seeding) due to stretching/flexing.
Exploring Symbiotic Nitrogen Fixation and Assimilation in Pea Root Nodules by in Vivo 15N Nuclear Magnetic Resonance Spectroscopy and Liquid Chromatography-Mass Spectrometry
Authors: Scharff Anne Marie , Egsgaard Helge , Hansen Poul Erik , Rosendahl Lis 
Published: January 2003

Abstract
Nitrogen (N) fixation and assimilation in pea (Pisum sativum) root nodules were studied by in vivo 15N nuclear magnetic resonance (NMR) by exposing detached nodules to15N2 via a perfusion medium, while recording a time course of spectra. In vivo 31P NMR spectroscopy was used to monitor the physiological state of the metabolically active nodules. The nodules were extracted after the NMR studies and analyzed for total soluble amino acid pools and 15N labeling of individual amino acids by liquid chromatography-mass spectrometry. A substantial pool of free ammonium was observed by 15N NMR to be present in metabolically active, intact nodules. The ammonium ions were located in an intracellular environment that caused a remarkable change in the in vivo 15N chemical shift. Alkalinity of the ammonium-containing compartment may explain the unusual chemical shift; thus, the observations could indicate that ammonium is located in the bacteroids. The observed15N-labeled amino acids, glutamine/glutamate and asparagine (Asn), apparently reside in a different compartment, presumably the plant cytoplasm, because no changes in the expected in vivo15N chemical shifts were observed. Extensive15N labeling of Asn was observed by liquid chromatography-mass spectrometry, which is consistent with the generally accepted role of Asn as the end product of primary N assimilation in pea nodules. However, the Asn 15N amino signal was absent in in vivo 15N NMR spectra, which could be because of an unfavorable nuclear Overhauser effect. γ-Aminobutyric acid accumulated in the nodules during incubation, but newly synthesized 15N γ-aminobutyric acid seemed to be immobilized in metabolically active pea nodules, which made it NMR invisible.
The Effects of Polyethylene Glycol on Gene Expression of Developing White Spruce Somatic Embryos
Authors: Stasolla Claudio , van Zyl Leonel , Egertsdotter Ulrika , Craig Deborah , Liu Wenbin , Sederoff Ron R. 
Published: January 2003

AbstractSomatic embryogenic cultures of white spruce (Picea glauca) represent a valuable system to study molecular mechanisms regulating embryo development because many embryos of defined developmental stages can be generated. The inclusion of polyethylene glycol (PEG) in the maturation medium can improve the number and quality of embryos produced. To learn more about the mechanism of action of PEG, we analyzed transcript profiles of stage-specific embryos matured without (control) or with (PEG treated) PEG. RNA extracted from maturing spruce embryos was analyzed on DNA microarrays containing 2,178 cDNAs from loblolly pine (Pinus taeda). The efficiency of heterologous hybridization between spruce and pine species on microarrays has been documented previously (L. van Zyl, S. von Arnold, P. Bozhkov, Y. Chen, U. Egertsdotter, J. MacKay, R. Sederoff, J. Shen, L. Zelena, D. Clapham [2002] Comp Funct Genomics 3: 306–318). Several pine genes, including the apparent homologs to the Arabidopsis genes ZWILLE, FIDDLEHEAD, FUSCA, and SCARECROW, increased in expression after PEG treatments. These genes are known to be involved in the formation of the embryo body plan and in the control of the shoot and root apical meristems. The increased transcript levels of these genes in immature PEG-treated embryos suggest that PEG may improve the quality of spruce somatic embryos by promoting normal differentiation of the embryonic shoot and root. Changes in the transcript levels of many genes involved in sucrose catabolism and nitrogen assimilation and utilization were also observed between control and PEG-treated embryos.
Quantitative Trait Loci Analysis of Nitrogen Use Efficiency in Arabidopsis
Authors: Loudet Olivier , Chaillou Sylvain , Merigout Patricia , Talbotec Joël , Daniel-Vedele Françoise 
Published: January 2003

Abstract
Improving plant nitrogen (N) use efficiency or controlling soil N requires a better knowledge of the regulation of plant N metabolism. This could be achieved using Arabidopsis as a model genetic system, taking advantage of the natural variation available among ecotypes. Here, we describe an extensive study of N metabolism variation in the Bay-0 × Shahdara recombinant inbred line population, using quantitative trait locus (QTL) mapping. We mapped QTL for traits such as shoot growth, total N, nitrate, and free-amino acid contents, measured in two contrasting N environments (contrasting nitrate availability in the soil), in controlled conditions. Genetic variation and transgression were observed for all traits, and most of the genetic variation was identified through QTL and QTL × QTL epistatic interactions. The 48 significant QTL represent at least 18 loci that are polymorphic between parents; some may correspond to known genes from the N metabolic pathway, but others represent new genes controlling or interacting with N physiology. The correlations between traits are dissected through QTL colocalizations: The identification of the individual factors contributing to the regulation of different traits sheds new light on the relations among these characters. We also point out that the regulation of our traits is mostly specific to the N environment (N availability). Finally, we describe four interesting loci at which positional cloning is feasible.
Plato's Division of Goods in the Republic
Authors: Heinaman Robert 
Published: January 2003

AbstractIn the Republic Plato draws a distinction among goods between (1) those that are good in themselves but not good for their consequences, (2) those that are good both in themselves and for their consequences, and (3) those that are not good in themselves but are good for their consequences. This paper presents an interpretation of this classification, in particular its application to the case of justice. It is argued that certain causal consequences of justice as well as factors that are not causal consequences of justice are relevant in explaining why justice is good in itself; and that it is only the reputation for justice and the causal consequences that follow from that reputation that are relevant in explaining why it is good for its consequences.
Aristotle on the Akratic's Knowledge
Authors: Grgić Filip 
Published: January 2003

AbstractThis paper is an analysis of Aristotle's Nicomachean Ethics 7.3. Aristotle's discussion in this chapter is motivated by the Socratic doctrine, elaborated in Plato's Protagoras, according to which it is impossible to know what is good and act against this knowledge. Aristotle wants to rebut this doctrine and show that there is a sense of "know" such that this is possible. I argue that this is all that he wants to do in EN 7.3, and that his discussion is not meant to provide an explanation of akrasia, as is usually supposed by commentators. Since the akratic knows that the action she is performing is not good for her, and actions are particulars, the akratic's knowledge is about a particular. I argue that Aristotle's discussion in EN 7.3 adds strength to the idea that knowledge of a particular is explainable only in terms of knowledge of a universal. More determinately, knowledge of a particular is explainable in terms of the actualization or use of knowledge of a universal, and such an actualization is in turn explainable by means of the syllogistic form. Thus, I argue that syllogisms in 7.3 (esp. at 1146b35-1147a10) are not "practical syllogisms", but that their function is epistemological: they are meant to reveal the structure and content of the akratic's knowledge, not to explain her actions.
The Development of Modus Ponens in Antiquity : From Aristotle to the 2nd Century AD
Authors: Bobzien Susanne 
Published: January 2003

Abstract'Aristotelian logic', as it was taught from late antiquity until the 20th century, commonly included a short presentation of the argument forms modus (ponendo) ponens, modus (tollendo) tollens, modus ponendo tollens, and modus tollendo ponens. In late antiquity, arguments of these forms were generally classified as 'hypothetical syllogisms'. However, Aristotle did not discuss such arguments, nor did he call any arguments 'hypothetical syllogisms'. The Stoic indemonstrables resemble the modus ponens/tollens arguments. But the Stoics never called them 'hypothetical syllogisms'; nor did they describe them as ponendo ponens, etc. The tradition of the four argument forms and the classification of the arguments as hypothetical syllogisms hence need some explaining. In this paper, I offer some explanations by tracing the development of certain elements of Aristotle's logic via the early Peripatetics to the logic of later antiquity. I consider the questions: How did the four argument forms arise? Why were there four of them? Why were arguments of these forms called 'hypothetical syllogisms'? On what grounds were they considered valid? I argue that such arguments were neither part of Aristotle's dialectic, nor simply the result of an adoption of elements of Stoic logic, but the outcome of a long, gradual development that begins with Aristotle's logic as preserved in his Topics and Prior Analytics; and that, as a result, we have a Peripatetic logic of hypothetical inferences which is a far cry both from Stoic logic and from classical propositional logic, but which sports a number of interesting characteristics, some of which bear a cunning resemblance to some 20th century theories.
The Cyrenaics on Pleasure, Happiness, and Future-Concern
Authors: O'Keefe Tim 
Published: January 2003

AbstractThe Cyrenaics assert that (1) particular pleasure is the highest good, and happiness is valued not for its own sake, but only for the sake of the particular pleasures that compose it; (2) we should not forego present pleasures for the sake of obtaining greater pleasure in the future. Their anti-eudaimonism and lack of future-concern do not follow from their hedonism. So why do they assert (1) and (2)? After reviewing and criticizing the proposals put forward by Annas, Irwin and Tsouna, I offer two possible reconstructions. In the first reconstruction, I explain claim (1) as follows: happiness has no value above and beyond the value of the particular pleasures that compose it. Also, there is no "structure" to happiness. The Cyrenaics are targeting the thesis that happiness involves having the activities of one's life forming an organized whole, the value of which cannot be reduced to the value of the experiences within that life. I explain claim (2) as follows: a maximally pleasant life is valuable, but the best way to achieve it is to concentrate heedlessly on the present. In the second reconstruction, the good is radically relativized to one's present preferences. The Cyrenaics assert that we desire some particular pleasure, e.g., the pleasure that results from having this drink now. Thus, our telos - which is based upon our desires - is this particular pleasure, not (generic) 'pleasure' or the maximization of pleasure over our lifetime. As our desires change, so does our telos. I conclude that the scanty texts we have do not allow us to decide conclusively between these reconstructions, but I give some reasons to support the second over the first.
Growth cycle of the marbled newt (Triturus marmoratus) in the Mediterranean region assessed by skeletochronology
Authors: Jakob Christiane , Seitz Alfred , Miaud Claude , Crivelli Alain 
Published: January 2003

AbstractWe studied growth patterns within a marbled newt population (Triturus marmoratus, Urodela) at the southeastern limit of its geographical range by skeletochronology of the phalanges and humeri. Seasonal and annual changes in growth rates were assessed through the analyses of 56 females, 66 males and 34 juveniles sampled in different seasons and years. Age and growth cycles were estimated by cross sections of the diaphyseal region of the bone. These analyses revealed a clear line of metamorphosis caused by the metamorphic process itself and the transition to the terrestrial environment. A line of arrested growth (LAG) was observed in winter in both juveniles and adults. Another LAG was recorded in summer among adults. These growth patterns corroborated field observations on life-history traits of the population under study, but differ from those reported for the marbled newt in other environments.
Molecular phylogeny of the salamandrid genus Neurergus: evidence for an intrageneric switch of reproductive biology
Authors: Öz Mehmet , Tautz Diethard , Steinfartz Sebastian , Hwang Ui Wook , Veith Michael 
Published: January 2003

AbstractA molecular phylogeny of the salamandrid genus Neurergus was reconstructed based on two sections of the 12S and 16S mitochondrial ribosomal genes (810 bp), 19 allozyme and three plasma protein loci. When representative species of all closely related salamandrid groups were included, mitochondrial data provided evidence for monophyly of Neurergus within the Salamandridae. Mitochondrial and allozyme data showed homogenous intrageneric tree topologies, but different estimates of times of separation. We calibrated the evolutionary rate to 0.46% pairwise sequence divergence per million years. Accordingly Neurergus diverged 18 million years ago (mya) from a lineage that comprised Euproctus asper and large bodied newts of the genus Triturus. A split around 11 mya produced two major clades within Neurergus. Further separation within the southern 'N. crocatus-clade' (comprising N. crocatus, N. microspilotus and N. kaiseri) occurred ca. 5 mya. The northern 'N. strauchii-clade' separated into N. s. strauchii and N. s. barani ca. 3 mya. Our molecular phylogeny indicates that stream-reproduction is the ancestral state for Neurergus, adaptations to pond-reproduction in N. kaiseri are the result of an evolutionary switch of reproductive biology within the 'N. crocatus-clade'.
Hatching dynamics and bet-hedging in a temperate frog, Pseudophryne australis (Anura: Myobatrachidae)
Authors: Mahony Michael , Thumm Karen 
Published: January 2003

AbstractEmbryonic development to the time of hatching was found to vary within and between clutches of the red crowned toadlet, Pseudophryne australis. Hatching occurred over many developmental stages, from 24 to 36 (modified Gosner stage). The time taken from oviposition to hatching varied from 15 days to 119 days. In order to determine whether hatching is triggered by environmental cues or is constitutive, clutches were held under constant conditions and compared with those held under conditions similar to the field. Hatching was staggered in all cases implying a constitutive basis. We postulate that this diversification of phenotypes in P. australis is a bet-hedging strategy driven by the unpredictable rainfall conditions within the range of the species. Die Entwicklung der Embryonen des australischen Frosches Pseudophryne australis bis zum Schlüpfen variierte innerhalb und zwischen Gelegen. Das Schlüpfen trat bei vielen Entwicklungsstadien ein. Der Zeitverlauf bis zum Schlüpfen variierte zwischen 15 und 119 Tagen. Gelege wurden unter konstanten Bedingungen gehalten und mit Gelegen in natürlichen Bedingungen verglichen, um festzustellen, ob das Schlüpfen durch Umweltreize angeregt wird, oder ob das Schlüpfen konstitutiv ist. Da das Schlüpfen in allen Behandlungen versetzt war, wird vermutet, dass das Schlüpfverhalten konstitutiv ist. Wir postulieren, dass die Verschiedenartigkeit der Phänotypen bei Pseudophryne australis eine vorbeugende Strategie ist, die durch die nicht voraussagbaren Niederschlagsverhältnisse im Verbreitungsgebiet der Art bedingt wird.
A new species of frog, genus Sooglossus (Anura, Sooglossidae) from Silhouette Island, Seychelles
Authors: Willi Johanna , Gerlach Justin 
Published: January 2003

AbstractA new species of frog of the genus Sooglossus (Sooglossidae) is described. The family is restricted to Mahé and Silhouette islands in Seychelles. Three species have been described previously (Nesomantis thomasseti, Sooglossus sechellensis and S. gardineri), all found on both islands. A new species is described from Silhouette island; it is associated with the Seychelles endemic palm tree Phoenicophorium borsigianum.
Podarcis carbonelli Pérez-Mellado, 1981 is a distinct species
Authors: Harris D. James , Sá-Sousa Paulo 
Published: January 2003

AbstractPodarcis carbonelli is considered a full species on the basis of its morphological and genetic divergence from P. bocagei and P. hispanica. Podarcis carbonelli differs from P. bocagei in all twelve biometric variables compared and also in chromatic patterns. Podarcis carbonelli diverges from P.bocagei by more than 13% between cytochrome b sequences (mitochondrial DNA), a value typically reported between congeneric reptile species. Biogeographical criteria also support this hypothesis, as both lizard forms have different distribution ranges with a limited parapatric zone of contact without morphological intermediates.
Varanid combat: perspectives from game theory
Authors: Eason Perri , Attum Omar , Earley Ryan 
Published: January 2003

AbstractMost data on aggressive encounters in varanid lizards are qualitative and often anecdotal. The few quantitative reports have not explicitly tested the predictions generated by game theoretical models of animal combat despite their apparent relevance. The goal of this paper was to investigate whether the patterns evident in varanid contests conform to the predictions of the sequential assessment game with special emphasis on the organization, duration, and outcome of the encounters. Several characteristics of monitor combat are consistent with the sequential assessment game. For instance, contests are organized into distinct phases, displays are repeated within each phase, and asymmetries play a crucial role in determining contest duration and outcome. However, data pertaining to a number of the sequential assessment game's most critical postulations are absent from the current varanid literature (e.g. the consistency of display intensity within each phase). As more quantitative data emerge, the applicability of the sequential assessment game to varanid contests may be better assessed.
The feeding behavior of the snail-eating snake Pareas carinatus Wagler 1830 (Squamata: Colubridae)
Authors: Götz Matthias 
Published: January 2003

AbstractThe behavior of captive Pareas carinatus feeding on European round-shelled snails is described. The snake bites into the snail's body and lifts it from the ground. With alternate retraction movements of the mandibles, it pulls the body out of the shell while the upper jaw rests on the outside of the shell. There are only slight differences to dipsadine snakes: Pareas never followed a mucus track and did not coil around the snail's shell. There seemed to be a preference to catch the snails from behind. Extraction time (24-390 s) and number of mandibular movements (22-98) were similar to the data on the dipsadines.
Reproductive biology of the false coral snake Oxyrhopus guibei (Colubridae) from southeastern Brazil
Authors: Marques Otavio , Pizzatto Lígia 
Published: January 2003

AbstractThe reproductive biology of the false coral snake, Oxyrhopus guibei, was studied through dissection of 496 specimens, combined with observations on captive individuals. Males mature with smaller body size than females, females attain much larger body size, and male-male combat is not expected. Clutch size ranged from 3 to 20, and was correlated with female length. Reproductive cycles in both males and females seem to be continuous, with vitellogenesis and spermatogenesis occurring throughout the year. Reproductive activity in both sexes decreased at the end of the rainy season possibly due to previous intense reproductive activity in more favorable climatic conditions. The smaller number of individuals collected at the end of the rainy season apparently occurs due to the decrease of reproductive activity of this snake.
Combined anticoagulant and antiselectin treatments prevent lethal intravascular coagulation
Authors: Norman Keith E. , Cotter Matthew J. , Stewart James B. , Abbitt Kate B. , Ali Majid , Wagner Bart E. , Wallace William A. H. , Forlow S. Bradley , Hellewell Paul G. 
Published: January 2003

AbstractWidespread microvascular injury followed by vessel obstruction may lead to disseminated intravascular coagulation (DIC). We describe a murine model wherein leukocytes interacting with inflamed microvessels in vivo are activated by antibodies. Treatment of tumor necrosis factor α (TNF-α)–primed mice with anti–Ly-6G antibodies reproduced many of the features of septic or traumatic shock including microvessel obstruction and coagulation, severe vasculitis, respiratory difficulties, and vascular leakage. Mice lacking either E-selectin or P-selectin were protected from this reaction as were animals treated with a combination of either selectin-blocking antibodies and heparin or a selectin antagonist plus heparin. Combined blockade of leukocyte/platelet adhesion and coagulation may provide convincing protection in DIC.