bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional response, numerical response, and stability in arthropod predator‐prey ecosystems involving age structure
Authors: Wollkind D. J. , Hastings A. , Logan J. A. 
Published: December 2006

SummaryA general model of arthropod predator‐prey systems incorporating age structure in the predator is employed to study the role of functional and numerical responses on stability and the paradox of enrichment. The destabilizing effect of age structure leads to both qualitatively and quantitatively new results for an environment which has an infinite prey carrying capacity, including a lower bound to prey density for a stable equilibrium, a feature not present in models without age structure. When applied to an environment with finite prey carrying capacity, the effect of age structure is to reinforce the arguments implicit to the paradox of enrichment originally developed for traditional models lacking age structure.
Predation of Apochthonius minimus (Pseudoscorpionida: Chthoniidae) on Folsomia canadida (Collembola: Isotomidae)
Authors: Johnson Dan L. , Wellington W. G. 
Published: December 2006

SummaryWe investigated the functional response of the predaceous pseudoscorpion, Apochthonius minimus, to density of the springtail, Folsomia candida, as well as the effects of temperature and prey size on handling time and attack rate. Temperature slightly altered the overall rise in response. Both the rise and shape of the response differed for two prey sizes.The changes in number of prey eaten over a 48‐hour period were also examined, and the attack and feeding behaviour of A. minimus was described and discussed in relation to the predation experiments. The pseudoscorpion preferred young adult F. candida, 0.8–1.2 mm in length, when offered prey in the range, 0.2–1.5 mm.
Frequency distribution of catch per tow by the danish trawlers in the waters off the Bristol Bay, with some considerations on the relation of total catch to the weight limit of hauling
Authors: Maéda Hiroshi , Nakada Yutaka , Fujiwara Kinjiro 
Published: December 2006

Summary
The type of the frequency distribution of catch per tow observed by the Danish trawlers of a fish‐meal fleet in the waters off the Bristol Bay during the period from May 1 to 9 in 1960 in discussed.
Catch per tow varied considerably from as much as one ton to ten tons and the tow‐time also did markedly tow by tow from one to thirty minutes or longer. Therefore, as a preliminary step to discuss the type of the frequency distribution, we examined whether catch varied depending on the tow‐time or not; and we found the catch deviated almost independently of the tow‐time.
Here, however much fish might be caught by a two, the part over ten tons was released; consequently, the frequency increased gradually from zero to nine tons and increased abruptly at ten tons but none of the haul could get a better catch than ten tons. And examining the relation between Student's t and the grade of catch in tons (n) in the range from zero to nine tons, we found that such a peculiar type of the frequency distribution as observed actually was derived from the series of the catch well fitted for the normal distribution by the modification due to releasing of a part of catch. This fact evolved, the possible series of the frequencies and the total of the possible catch when no part of catch is released, are estimated.
Then some considerations are given to the problem (1) how high percentage of the catch on the total of the possible catch is obliged to release because of the low weight limit of hauling and (2) to what percentage of the catch we can successfully make into available when we increase the weight limit of hauling to a certain value; and the results is shown in Fig. 3, which tells that (1) 70 to 95 percents of the catch were available in the actual operation and (2) scarecely any increase in catch is expected even if the weight limit of hauling is increased higher than fifteen tons.
Growth of the stocked ayu‐fish in pond already inhabited by some fish of the same species
Authors: Kodama Yasuo 
Published: December 2006

Summary
In a small test pond, growth of the newly stocked ayu‐fish was compared with that of the fish which was stocked earlier in time and had inhabited in the pond. The test was repeated under conditions of three different levels of density.
In every tests, the newly stocked group of fish was, at least in the first three weeks, more or less inferior to the inhabited group in growth. The cause of this phenomenon was assumed to be related with the difficulty for the later stocked ayu‐fish to find proper territory to defend in the pond against other members of the same species of fish.
Survival curves of the population of dendrolimus spectabilis Bulter (Lepidoptera: Lasiocampidae)
Authors: Kanamitsu Keiji 
Published: December 2006

SummarySix survival curves were drawn (Fig. 1) from a survey over two generations of the population of Dendro'imus spectabi'isButler at three different places in the Tokyo University Forest in Aichi during the years from 1957 to 1959.The counting of insect number was done at one month interval except during the winter season. Any apparent mortality expressed as percentage decrease was not related in this survey with the density of insect population at the beginning of each interval.Considering of the magnitude and the variability of each apparent mortality, there were three critical periods of heavy decrease in the generation decline, they were; 1) September to October when newly born larvae were dispersing, 2) December to March when the third instar larvae were overwintering, and 3) August to September for the period of fully grown larvae and pupae.
Oviposition schedules, survivorship curves, and mortality factors within trees of two cerambycid beetles (Coleoptera: Cerambycidae), the Japanese pine sawyer, Monochamus alternatus hope, and sugi bark borer, Semanotus japonicus lacordaire
Authors: Shibata Ei'ichi 
Published: December 2006

SummaryOviposition schedules under laboratory conditions, survivorship curves, and mortality factors within trees of two cerambycid beetles, Japanese pine sawyer (JPS),Monochamus alternatusHope, and sugi bark borer (SBB),Semanotus japonicusLacordaire, were investigated. Average longevities of reared adults of JPS were 38.1 days for males and 42.3 days for females; those of SBB were 15.7 days for males and 23.8 days for females. It was confirmed that the JPS must feed on the pine branches for full maturation after emergence, but SBB need not; they are able to lay eggs soon after emergence. The average fecundities of JPS and SBB were 32.9 and 90.5, respectively. Thus, the JPS lay fewer eggs for a long time with continuous maturation feeding, whereas the SBB lay more eggs for short time without maturation feeding. Average survivorship curves of JPS within dead pine trees in 8 pine forests were theDeevey's B type, showing a constant mortality through the pre‐imaginal stages in the trees. On the other hand those of SBB in 4 cedar stands approached theDeevey's type, suggesting that the high mortality occurred at an early stage in the trees. Average mortalities of JPS between the appearance of oviposition scars and adult emergence in 8 forests ranged from 62.3% to 95.2%. Intraspecific ompetition of JPS resulting from overcrowding in dead pine trees appeared to be main mortality factor. For SBB, as most larvae were killed by resin flow in living trees, this appeared to be the main mortality factor for this species.
Oxidation‐derived flavor compounds as quality indicators for packaged olive oil
Authors: Kanavouras Antonis , Hernandez‐Münoz Pilar , Coutelieris Frank , Selke Susan 
Published: December 2006

AbstractAroma compounds in packaged extra virgin olive oil can be present naturally or be derived through oxidative degradation under favorable conditions of temperature, light, and oxygen availability. In this study, the identity and quantity of flavor compounds were determined for extra virgin olive oil packaged in 0.5‐L glass, poly(ethylene terephthalate), and poly(vinyl chloride) bottles and stored at 15,30, and 40°C under fluorescent light or in the dark for 1 yr. A set of mathematical equations concerning the rates of the most fundamental oxidation reactions in the oil was prepared and numerically solved, and the reaction constants were estimated for specific temperature values. Mainly, the presence of fluorescent light, followed by elevated temperature, stimulated oxidative alterations in the olive oil. Separated and identified flavor compounds were recorded for all the olive oil samples. Based on their abundance and evolution in the oil samples, those most clearly describing oxidation were hexanal, nonanal, (E)‐2‐decenal, (E)‐2‐heptenal, and 2‐pentyl furan. These compounds could be used as markers of the oxidation process to monitor and describe the quality of packaged olive oil quantitatively.
Synthesis and physical properties of cuphea‐oleic estolides and esters
Authors: Cermak Steven C. , Isbell Terry A. 
Published: December 2006

AbstractCuphea‐oleic estolides and esters were synthesized from cuphea and oleic FA with various amounts of perchloric acid (0.01 to 0.40 equiv) at 60°C. Estolide yields ranged from 30 to 65% after Kugelrohr distillation. Estolide number (EN), the average number of FA units added to a base FA, varied with reaction conditions. Cuphea‐oleic estolides were esterified with 2‐ethylhexanol to obtain high yields of the corresponding ester. A streamlined, one‐pot process was used to synthesize the estolide and its ester with 0.05 equiv of HClO4, with, esterification incorporated into an in situ second step to provide a functional fluid at a very reasonable cost. The physical properties of the cuphea‐oleic estolides and estolide esters, including their viscosities, pour points, and cloud points, were related directly to the amount of oligomerization (EN), i.e., viscosity increased with higher oligomerization. The viscosity index ranged from 132 to 166 cSt for the free‐acid estolides, whereas the complex estolide 2‐ethylhexyl esters had slightly high viscosity indices that ranged from 165 to 181 cSt. These new cuphea‐oleic estolide esters displayed good low‐temperature properties (pour point −42°C and cloud point −41°C).
Production of Polyols from Canola Oil and their Chemical Identification and Physical Properties
Authors: Narine Suresh S. , Yue Jin , Kong Xiaohua 
Published: December 2006

AbstractThe feasibility of a method based on ozonolysis and hydrogenation reactions for the production of polyols from unsaturated canola oil has been demonstrated. Polyol products with primary alcohol functional groups at position nine of each fatty acid ester in the original triacylglycerol have been produced from canola oil. Short straight‐chain alcohols were also produced and were removed by wiped‐blade molecular distillation. The pure components of the polyol, i.e. mono‐ol, diol and triol were separated by flash chromatography, and identified by Fourier‐transform infrared (FTIR), 1H‐nuclear magnetic resonance (NMR), 13C‐NMR as well as mass spectrometry. Polyol identification was facilitated by the use of a simple high‐performance liquid chromatography (HPLC) method to determine the composition of the polyol mixture, which can be exploited as a quality‐control mechanism in designing novel polyol feedstocks. Basic correlations were established between the molecular diversity of the polyols and their physicochemical properties, such as hydroxyl number, acidity number, and viscosity. It has been found that the produced polyols are suitable for processing methods employing polyols for the production of polyurethanes and can be manipulated to create polyurethanes with desirable properties.
Localization of the binding site of the C-terminal domain of cardiac myosin-binding protein-C on the myosin rod
Authors: Flashman Emily , Watkins Hugh , Redwood Charles 
Published: December 2006

cMyBP-C [cardiac (MyBP-C) myosin-binding protein-C)] is a sarcomeric protein involved both in thick filament structure and in the regulation of contractility. It is composed of eight IgI-like and three fibronectin-3-like domains (termed C0–C10). Mutations in the gene encoding cMyBP-C are a principal cause of HCM (hypertrophic cardiomyopathy). cMyBP-C binds to the LMM (light meromyosin) portion of the myosin rod via its C-terminal domain, C10. We investigated this interaction in detail to determine whether HCM mutations in β myosin heavy chain located within the LMM portion alter the binding of cMyBP-C, and to define the precise region of LMM that binds C10 to aid in developing models of the arrangement of MyBP-C on the thick filament. In co-sedimentation experiments recombinant C10 bound full-length LMM with a Kd of 3.52 μM and at a stoichiometry of 1.14 C10 per LMM. C10 was also shown to bind with similar affinity to LMM containing either the HCM mutations A1379T or S1776G, suggesting that these HCM mutations do not perturb C10 binding. Using a range of N-terminally truncated LMM fragments, the cMyBP-C-binding site on LMM was shown to lie between residues 1554 and 1581. Since it had been reported previously that acidic residues on myosin mediate the C10 interaction, three clusters of acidic amino acids (Glu1554/Glu1555, Glu1571/Glu1573 and Glu1578/Asp1580/Glu1581/Glu1582) were mutated in full-length LMM and the proteins tested for C10 binding. No effect of these mutations on C10 binding was however detected. We interpret our results with respect to the localization of the proposed trimeric collar on the thick filament.
Ribose 5-phosphate isomerase type B from Trypanosoma cruzi: kinetic properties and site-directed mutagenesis reveal information about the reaction mechanism
Authors: Stern Ana L. , Burgos Emmanuel , Salmon Laurent , Cazzulo Juan J. 
Published: December 2006

Trypanosoma cruzi, the human parasite that causes Chagas disease, contains a functional pentose phosphate pathway, probably essential for protection against oxidative stress and also for R5P (ribose 5-phosphate) production for nucleotide synthesis. The haploid genome of the CL Brener clone of the parasite contains one gene coding for a Type B Rpi (ribose 5-phosphate isomerase), but genes encoding Type A Rpis, most frequent in eukaryotes, seem to be absent. The RpiB enzyme was expressed in Escherichia coli as a poly-His tagged active dimeric protein, which catalyses the reversible isomerization of R5P to Ru5P (ribulose 5-phos-phate) with Km values of 4 mM (R5P) and 1.4 mM (Ru5P).
4-Phospho-D-erythronohydroxamic acid, an analogue to the reaction intermediate when the Rpi acts via a mechanism involving the formation of a 1,2-cis-enediol, inhibited the enzyme competi-tively, with an IC50 value of 0.7 mM and a Ki of 1.2 mM. Site-directed mutagenesis allowed the demonstration of a role for His102, but not for His138, in the opening of the ribose furanosic ring. A major role in catalysis was confirmed for Cys69, since the C69A mutant was inactive in both forward and reverse directions of the reaction. The present paper contributes to the know-ledge of the mechanism of the Rpi reaction; in addition, the absence of RpiBs in the genomes of higher animals makes this enzyme a possible target for chemotherapy of Chagas disease.
Activation of the ATF3 gene through a co-ordinated amino acid-sensing response programme that controls transcriptional regulation of responsive genes following amino acid limitation
Authors: Pan Yuan-Xiang , Chen Hong , Thiaville Michelle M. , Kilberg Michael S. 
Published: December 2006

Expression of ATF3 (activating transcription factor 3) is induced by a variety of environmental stress conditions, including nutrient limitation. In the present study, we demonstrate that the increase in ATF3 mRNA content following amino acid limitation of human HepG2 hepatoma cells is dependent on transcriptional activation of the ATF3 gene, through a highly co-ordinated amino acid-responsive programme of transcription factor synthesis and action. Studies using transient over-expression and knockout fibroblasts showed that several ATF and C/EBP (CCAAT/enhancer-binding protein) family members contribute to ATF3 regulation. Promoter analysis showed that a C/EBP-ATF composite site at −23 to −15 bp relative to the transcription start site of the ATF3 gene functions as an AARE (amino acid response element). Chromatin immunoprecipitation demonstrated that amino acid limitation increased ATF4, ATF3, and C/EBPβ binding to the ATF3 promoter, but the kinetics of each was markedly different. Immediately following histidine removal, there was a rapid increase in histone H3 acetylation prior to an enhancement in ATF4 binding and in histone H4 acetylation. These latter changes closely paralleled the initial increase in RNA pol II (RNA polymerase II) binding to the promoter and in the transcription rate from the ATF3 gene. The increase in ATF3 and C/EBPβ binding was considerably slower and more closely correlated with a decline in transcription rate. A comparison of the recruitment patterns between ATF and C/EBP transcription factors and RNA polymerase II at the AARE of several amino acid-responsive genes revealed that a highly co-ordinated response programme controls the transcriptional activation of these genes following amino acid limitation.
Confronting Categorical Assumptions About the Power of Religion in Africa
Authors: Green Maia 
Published: December 2006

This article examines the place of religion in social science accounts of Africa, particularly as they relate to politics and culture. It explores the significance of representational continuities across the twentieth century and across disciplines which present African social life as religiously determined, and considers the political implications of African exceptionalism as a mode of analysis and policy rationale. Finally, the article considers some directions of institutional change in southern Tanzania and the consequences for understanding religion.
This paper is based on a workshop organised by ROAPE on religion and politics in Africa held at the University of Leeds in February 2006. Some of the arguments made in the paper concerning detotalisation and deconversion were developed through discussions at a workshop on history and anthropology held at the University of Manchester in November 2005.
Integrating stream bioassessment and landscape ecology as a tool for land use planning
Authors: BAILEY ROBERT C. , REYNOLDSON TREFOR B. , YATES ADAM G. , BAILEY JOHN , LINKE SIMON 
Published: December 2006

Summary1. Bioassessment has evolved significantly from a method of deciding whether an ecosystem exposed to stressors should ‘pass’ or ‘fail’ (or how badly it fails). Society wants some notion of what has caused any observed degradation of ecosystems, and what management strategies might improve degraded ecosystems. Managers also want to predict what negative or positive effects different land use strategies will have on the component ecosystems of a landscape, including lakes and streams.2. Here we illustrate an approach to providing these tools to managers with data from a bioassessment study of streams in the Fraser River Basin of British Columbia, Canada.3. Landscape scale descriptors of both the natural (e.g. catchment size, surficial geology) and stressor (e.g. hard rock mines, forest harvest) environment of each site were used to define the natural and stressor environments of each of the 242 stream sites.4. We classified 206 reference (relatively unexposed to human activity) sites using their benthic macroinvertebrate community composition, and then discriminated among the faunally defined groups with landscape scale descriptors of the natural environment of the sites.5. This discriminant function model allowed us to predict which group each of the test sites would be in if it were in reference condition, and then measure the relationship between the amount of human activity and the biota in each of these groups.6. These relationships were turned into projections of what will happen to a stream ecosystem's biota if the stressor environment is either improved or degraded. These projection models form the basis of evidence‐based land use planning that takes into account the health of freshwater ecosystems.
Tobacco zygotic embryogenesis in vitro: the original cell wall of the zygote is essential for maintenance of cell polarity, the apical–basal axis and typical suspensor formation
Authors: He Yu‐Chi , He Yu‐Qing , Qu Liang‐Huan , Sun Meng‐Xiang , Yang Hong‐Yuan 
Published: December 2006

SummaryWe have developed a reliable in vitro zygotic embryogenesis system in tobacco. A single zygote of a dicotyledonous plant was able to develop into a fertile plant via direct embryogenesis with the aid of a co‐culture system in which fertilized ovules were employed as feeders. The results confirmed that a tobacco zygote could divide in vitro following the basic embryogenic pattern of the Solanad type. The zygote cell wall and directional expansion are two critical points in maintaining apical–basal polarity and determining the developmental fate of the zygote. Only those isolated zygotes with an almost intact original cell wall could continue limited directional expansion in vitro, and only these directionally expanded zygotes could divide into typical apical and basal cells and finally develop into a typical embryo with a suspensor. In contrast, isolated zygote protoplasts deprived of cell walls could enlarge but could not directionally elongate, as in vivo zygotes do before cell division, even when the cell wall was regenerated during in vitro culture. The zygote protoplasts could also undergo asymmetrical division to form one smaller and one larger daughter cell, which could develop into an embryonic callus or a globular embryo without a suspensor. Even cell walls that hung loosely around the protoplasts appeared to function, and were closely correlated with the orientation of the first zygotic division and the apical–basal axis, further indicating the essential role of the original zygotic cell wall in maintaining apical–basal polarity and cell‐division orientation, as well as subsequent cell differentiation during early embryo development in vitro.
Chlamydospore formation in Candida albicans and Candida dubliniensis– an enigmatic developmental programme
Authors: Staib Peter , Morschhäuser Joachim 
Published: December 2006

SummaryChlamydospore formation has served for a long time for identification of the human fungal pathogen Candida albicans, but the biological function of these structures still remains a secret. They have been proposed to allow survival in harsh environmental conditions, but this assumption remains to be proven. Chlamydospores are produced only by the two closely related species C. albicans and Candida dubliniensis, whose natural habitats are humans and warm‐blooded animals, but not by other Candida species that are also found outside animal hosts. However, no role in the pathogenesis of Candida infections has been assigned to these unusual cells and only a limited number of studies have been conducted in the past to unravel their function. The development of new molecular tools and the recent discovery of mating in C. albicans have also restimulated investigations to understand the morphogenesis and function of chlamydospores. The finding that chlamydospore formation is differentially controlled by certain environmental signals in C. albicans and C. dubliniensis has opened new approaches to study the regulation of this morphogenetic programme. These studies have already identified genes and signalling pathways that are required for chlamydospore production and should lead to a detailed understanding of this fascinating developmental process.