bluuebunny/crossref_metadata_2025_split huggingface dataset:
Content and distribution of arsenic in soils, sediments and groundwater environments of the southern Pampa region, Argentina
Authors: Blanco M. del C. , Paoloni J. D. , Morrás H. J. M. , Fiorentino C. E. , Sequeira M. 
Published: November 2006

AbstractThe health of a large rural population in the southern Pampa (Argentina) is at risk owing to newly detected areas where As‐groundwater exceeds 0.01 mg/L standard (WHO (1995) Guidelines for drinking water quality, 2nd edition. pp 43–45). Currently, devitrification of volcanic glass is invoked to interpret the origin of arsenic in the aquifers hosted in a sequence of pampean loess (Plio‐Pleistocene) juxtaposed with postpampean loess (Holocene). Our data suggest that arsenic is not specifically associated with volcanic glass and that other minerals contribute to As‐release into groundwater. The goals were (1) to understand As‐groundwater spatial variability, (2) to explore soils/sediments/water relationships and to identify the probable As‐provenance. Comparable As concentrations of the light and the heavy sand fractions suggest that though detrital glass is a major light constituent, other existing primary minerals are As‐bearers that contribute to As‐release into groundwater. Grouping of materials according to their As‐content indicated spatial variability in the sedimentary distribution pattern leading to differences in the frequencies of occurrence of As‐bearing minerals. Phreatic waters were Ca + Mg bicarbonate and devoid of As in the intake areas (Ventania System) and Na‐carbonate but As‐rich towards the discharge (Atlantic coast and local depressions). As‐groundwater reflects a patchy distribution within the pampean landscape. A correspondence between As‐high groundwater, EC >1 dSm, CO3H−, alkaline pH and a longer water residence time do exist triggering As extraction from the loess sand fraction and desorption from charged fine particles which lead to As‐toxicity towards groundwater discharge. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 561–574, 2006.
Oral toxicity of the cyanobacterial toxin cylindrospermopsin in mice: Long‐term exposure to low doses
Authors: Sukenik A. , Reisner M. , Carmeli S. , Werman M. 
Published: November 2006

AbstractThe hepatotoxin cylindrospermopsin, a sulfated‐guanidinium alkaloid with substituted dioxypyrimidine (uracil) moiety, was isolated from several cyanobacteria species. The acute toxicity of cylindrospermopsin was well established based on intraperitoneal and oral exposure; however, only a few long‐term subacute exposure studies were performed to permit a reliable guideline value for cylindrospermopsin in drinking water. In the study reported herein, female and male mice were exposed to cylindrospermopsin in their drinking water. Cylindrospermopsin‐containing, Aphanizomenon ovalisporum (cyanobacterium)‐free medium was provided as the only source of drinking water, whereas a control group was given a fresh medium for cyanobacteria as drinking water. Over a period of 42 weeks, experiment groups were exposed to cylindrospermopsin concentration, gradually increased from 100 to 550 μg L−1 (daily exposure ranged between 10 and 55 μg kg−1 day−1). Body and organ weights were recorded, and serum and hematology analyses were performed 20 and 42 weeks after the beginning of the experiment. The most pronounced effect of cylindrospermopsin was elevated hematocrit levels in both male and female mice after 16 weeks of exposure to cylindrospermopsin. The observed changes in the hematocrit level were accompanied by deformation of red blood cells, which were changed into acanthocyte. Based on these results, a daily cylindrospermopsin dose of 20 μg kg−1 day−1 (equivalent to 200 μg L−1) is proposed as the lowest‐observed‐adverse‐effect level for both male and female mice. © 2006 Wiley Periodicals, Inc. Environ Toxicol 21: 575–582, 2006.
Impacts per unit weight in catch by two types of fisheries on a chub mackerel population
Authors: Matsuda Hiroyuki , Fukase Kenjiro , Mitani Isamu , Asano Kenji 
Published: November 2006

AbstractBy using data on the age‐specific annual fecundity and catches‐at‐age by each fishery in a chub mackerel (Scomber japonicus) population in the Pacific Ocean off Japan during 1970 to 1992, we evaluated the long‐term fluctuation in impacts of two types of fisheries on the chub mackerel population. The purse‐seine fishery consistently had a larger impact on the population than did the dip‐net fishery, mainly because the catch by the former was much larger than that by the latter. To evaluate impact per unit weight in catch, we calculated the average reproductive value per unit weight over individuals caught by each fishery as an indicator of efficient use of bioresource. Because the proportion of immature fish caught by the purse‐seine fishery was usually larger than that by the dip‐net fishery, the impact per unit weight in catch by the purse‐seine fishery was not always less than that by the dip‐net fishery.
Demographic attributes of an introduced herbivorous lady beetle
Authors: Ohgushi Takayuki , Sawada Hiroichi 
Published: November 2006

AbstractDemographic attributes of the adults of an introduced herbivorous lady beetle Epilachna niponica (Coleoptera: Coccinellidae) were investigated from 1975 to 1981 in the Botanical Garden of Kyoto University. Population growth rate varied from 4.8 to 16.8 throughout the study period. Fecundity and mortality in the late larval period contributed most to annual changes in the population growth rate. Population growth rate was negatively correlated with the density of overwintering adults. Adult survival from emergence to the reproductive season, which varied from 0.03 to 0.36 throughout the study, was almost completely determined by survival during the pre‐hibernation period. Adult survival to the preproductive season changed in a size‐ and sex‐dependent manner. Larger adults survived better than smaller individuals; male‐biased mortality occurred from adult emergence to the reproductive age. Severe intraspecific competition among late instar larvae due to host plant defoliation produced a higher proportion of small‐sized adults, resulting in lower adult survival to hibernation. The introduced population had a higher population growth rate and a lower adult survival to the reproductive season than the source population.
Sexual differences in natal dispersal and philopatry of the grey‐sided vole
Authors: Saitoh Takashi 
Published: November 2006

AbstractThe natal dispersal distance of the grey‐sided vole, Clethrionomys rufocanus (Sundevall), was measured in a large outdoor enclosure (2.1 ha) in Hokkaido, Japan. Voles in about half of the enclosure (1 ha) were fed. Distance from the natal site to the site of reproduction was significantly greater in males (64.9 m) than in females (35.3 m). In males, 24.8% settled within one home range length of their natal site and 49.6% settled further than two range lengths from their natal site. In femles, the respective percentages were reversed: 51.2% and 22.0%. The timing of large movements (≥50 m) was related to body mass in both sexes. The population density was always higher on the fed grid than on the control grid, which resulted in the frequency of large movements being greater on the fed grid that on the control grid. Thus, the percentage of voles performing a large movement was not different between the grids in both sexes.
Emergent and effective properties in ecology and evolution
Authors: Kawata Masakado 
Published: November 2006

AbstractEmergent properties are often discussed in arguments concerning relationships among different levels. However, the different definitions of emergent properties sometimes confuse the arguments about macro‐level phenomena, since some authors regard emergent properties not only as observable global patterns but as properties that affect and cause change in ecological and evolutionary processes. Thus it is important to distinguish higher‐level or larger‐scale properties that can influence particular ecological and evolutionary processes from those that cannot. I call the former properties effective properties. I gave examples that show why the distinctions between effective and non‐effective properties are important.
Factors and consequences of a non‐functional alary polymorphism in Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae)
Authors: Honěk Alois 
Published: November 2006

AbstractFunctional alary polymorphisms have been studied rather extensively in several insect species. This review article deals with factors controlling wing polymorphism in a flightless species, Pyrrhocoris apterus (L.), and discusses its adaptive significance and mechanisms for their persistence under natural conditions. The macropterous morph is determined by a recessive allele whose penetrance depends on photoperiod and temperature. Natural populations of this species contain a small fraction of flightless macropters. The disadvantages of being a macropter (increase of development time, decrease of fecundity) are minimal, while the benefit may consist in the tendency to prereproductive arrest of ovarian development in teneral females. It prevents establishing a second generation which would mostly die during the next winter. The mechanism of alary morph regulation may be an ancestral trait linking P. apterus with other polymorphic Heteroptera, while its decreased penetrance may be a derivative character. Variation in fitness due to alary morphs is small compared to the one associated with differences in body size. The latter is environmentally determined, and not linked to the genetic basis of wing polymorphism. In the “mosaic” of phenotypes of various size the significance of the genetic macroptery may be close to neutral.
The dynamics of laboratory populations of Callosobruchus chinensis and C. Maculatus (Coleoptera: Bruchidae) in patchy environments
Authors: Hassell M. P. , Taylor V. A. , Reader P. M. 
Published: November 2006

SummaryExperiments are described showing the long‐term dynamics of two species of bruchid beetles (Callosobruchus chinensis and C. maculatus) in arenas in which the resource of 50 black‐eyed beans is divided between 5, 10 or 50 ‘patches’. Both species of adult beetles exhibit clumped distributions between patches. Within a patch there is a tendency for a density dependent reduction in (1) eggs laid per female, (2) the proportion of eggs hatching per bean (C. chinensis only) and (3) larval survival which is strongly overcompensating (particularly in C. maculatus). A discrete generation model is used as a framework to draw these results together and show how the different factors affecting natality and mortality can influence the population dynamics. Finally, the importance of the resource renewal interval in influencing the period of the population cycles is discussed.
A simulation study of population interaction between the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae), and the parasitoid Encarsia formosa gahan (Hymenoptera: Aphelinidae) I. Description of the model
Authors: Yano Eizi 
Published: November 2006

SummaryA simple simulation model was developed to simulate the population dynamics of the system of the greenhouse whitefly (Trialeurodes vaporariorumWestwood) and the parasitoid Encarsia formosaGahan. On the assumption that temperature is constant, the whitefly population was described as theLeslie Matrix model. Parasitization and host feeding by the parasitoid population were modelled by means of a modified disc equation. The validity of the model was demonstrated by comparing the predictions of the model with the observed values obtained in greenhouse experiments.
A simulation study of population interaction between the greenhouse whitefly, Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae) and the parasitoid Encarsia formosaGahan (Hymenoptera: Aphelinidae) II. Simulation analysis of population dynamics and strategy of biological control
Authors: Yano Eizi 
Published: November 2006

SummarySimulation studies were performed to analyze factors affecting the population dynamics of the system with the greenhouse whitefly (Trialeurodes vaporariorumWestwood) and the parasitoid Encarsia formosaGahan and to develop strategies for the introduction of E. formosa. The reduction of parasitization efficiency with an increase in parasitoid density promotes the stability of the system, which coincides with the prediction from current theory. The stability of the system is also shown to be promoted by the effect of host feeding. The population levels of the system are remarkably suppressed with an increase in searching efficiency and a decrease in host oviposition. The control effect of the parasitoids is enhanced when the number of parasitoids is divided among many introductions. An optimal time, an optimal density ratio of parasitoids to hosts and optimal densities of hosts and parasitoids exist in the introduction programme of parasitoids.
Density‐dependent predation of the antLasius niger(Hymenoptera: Formicidae) on two attended aphidsLachnus tropicalisandMyzocallis kuricola(Homoptera: Aphididae)
Authors: Sakata Hiroshi 
Published: November 2006

AbstractThe antLasius nigerwas observed collecting honeydew and preying on the two aphid speciesLachnus tropicalisandMyzocallis kuricolaon the chestnut treesCastanea crenata. Observation determined how the antL. nigercontrolled their predation on the aphids in response to the density and honeydew‐productivity of the aphids.Lachnus tropicaliswas a better honeydew source thanM. kuricolaforL. nigerin terms of the amount of honeydew collected per unit time by the ants. The number of foraging workers on a tree increased with the number ofL. tropicalison the tree, but not with the number ofM. kuricola. The density ofL. tropicalisperL. nigerworker on a tree had a positive effect on the predation activity ofL. nigeron both aphids, whereas the density ofM. kuricolaper ant did not have any significant effect. The predation pressure by the ant which increased withL. tropicalisdensity, however, directed toM. kuricolarather than toL. tropicalis. These facts suggest (1) thatL. nigercontrol their predation activities on aphids with regards to the densities of the attended aphids per worker, and (2) that the ants prey on the aphid species producing less honeydew. The effects of the ant predation on aphids and the importance of these predation effect in antaphids interactions were discussed.
Variation in offspring size within a population of the web‐building spider Agelena limbata
Authors: Tanaka Koichi 
Published: November 2006

AbstractWithin a population of the web‐building spider Agelena limbata, the weight of the first instar nymphs ranged from 1.187 to 6.559 mg. Both intraclutch and interclutch variation were recorded. The mean weights were different among clutches and the coefficients of variation within a clutch ranged from 3.3 to 29.2%. Variation in the nymphal weight was certainly derived from variation in the egg weight because there was a high correlation between the two weights. Factors affecting interclutch variation in nymphal weight were examined by multiple regression analysis. Nymphal weight was positively correlated with the body size and food conditions of female parents, and negatively correlated with the clutch size. Among these three factors, the food conditions of female parents had the largest apparent effect on the interclutch variation. The results suggest that females with larger body size and more food produce larger offspring, and that there is a trade‐off between offspring size and clutch size. Heavier nymphs had larger body size (carapace width) and may have larger energy reserves. Heavier nymphs survived experimental starvation for a significantly longer period.
The role of the brown‐eared bulbul Hypsypetes amaurotis as a seed dispersal agent
Authors: Fukui Akiko W. 
Published: November 2006

AbstractThe role of the brown‐eared bulbul, Hypsypetes amaurotis, as a dispersal agent for seeds of fruiting plants was studied by field observations for two years, in parallel with laboratory experiments on seed germination. Bulbuls consumed fruits of 53 species from 24 plant families. The fruits of these plants had similar color and size, and these characteristics were likely to enhance the feeding efficiency of the frugivore. Laboratory experiments on 20 food plant species demonstrated that: (1) no seeds were injured by passing through the bulbul's gut; (2) seeds that had passed through the bulbul's gut were still able to germinate and (3) fruit pulp reduced germination ability. When pulp was removed by passing through bulbul's gut, or by hand, germination was improved. An estimate of the home range of six bulbuls suggested that they may transport seeds for at least 300 m.
The outbreak mechanisms of the green rice leafhopper, Nephotettix cincticeps Uhler, in northern Japan
Authors: Hirano Kohji , Fujii Koichi 
Published: November 2006

AbstractIntraspecific regulatory processes keep the population of Nephotettix cincticeps stable at a low density in southern Japan. In northern Japan, however, the yearly population density of the insect fluctuates violently, and large outbreaks occasionally take place. To clarify the difference in the population dynamics between the two regions, we analyzed light‐trap and sweep‐net sampling records from prefectural and national agricultural experimental stations. The survival rate of the overwintering population decreased with increases in the period of continuous snow cover (PCSC) in the north, and initial population densities in the years of long PCSC were too low for populations to reach equilibrium density by the end of the active breeding season. This made yearly population fluctuations in the north much larger than in the south. The equilibrium density in the north was higher than in the south. The higher equilibrium density presumably permits the higher population density and larger yearly population fluctuations in the north. A major factor responsible for the difference in equilibrium densities between the two regions is the difference in heading dates of the host plant (rice). Qualitative differences among rice plant varieties, and among biotypes of N. cincticeps, may also be important.
Enzymatic extraction of mustard seed and rice bran
Authors: Sengupta R. , Bhattacharyya D. K. 
Published: November 2006

AbstractAqueous enzymatic extraction was investigated for recovery of oil from mustard seed and rice bran. The extraction process was reproducible based on statistical analysis of extraction data under different extraction conditions. The most significant factors for extraction were the time of digestion with enzymes, seed or bran concentration in water, volume of hexane added before recovery, and amount of enzyme(s) used. The pretreatment steps of each material before enzyme digestion influenced oil yield.Quality of enzyme‐extracted mustard oil was better with respect to color and odor than commercial expeller‐extracted and Soxhlet‐extracted oils. Most of the characteristics of rice bran oil were identical to those of commercial solvent‐extracted oils, but rice bran oil had a lower content of colored substances and higher acidity (free fatty acid). Enzymatic extraction led to recovery of a protein concentrate with increased protein and reduced fiber and ash contents in the mustard and rice bran meals.
Analysis of the volatile fraction from sunflower oil extracted under pressure
Authors: Bocci F. , Frega N. 
Published: November 2006

AbstractThis study concerns the analysis of volatile components that may contribute to the formation of the flavor of the oil extracted from sunflower seeds. The compounds were trapped on a charcoal cartridge, then desorbed and analyzed by gas chromatography/mass spectrometry. The principal compounds were terpenes (about 225 mg/L) consisting of α‐pinene (80%), limonene (5%), sabinene (3.3%), β‐pinene (1.8%), 1,2,6,6‐tetramethyl‐1,3‐cyclohexadiene (1.5%), and camphene (1.2%). There were also a small amount of hexanal (1.3%) and traces (<1%) of unidentified compounds, which probably correspond to other terpenic hydrocarbons and to terpenic alcohols and/or aldehydes.
Potential margarine oils from genetically modified soybeans
Authors: List G. R. , Mounts T. L. , Orthoefer F. , Neff W. E. 
Published: November 2006

AbstractGenetically modified soybeans were processed into finished, refined, bleached, and deodorized oils. Fatty acid composition was determined by gas‐liquid chromatography. Glyceride structure was characterized according to degree of unsaturation by high‐performance liquid chromatography, lipase hydrolysis, and gas‐liquid chromatography. Compared to common varieties with 15% saturated acids, genetically modified soybeans yielded oils containing 24–40% saturated acids. Several varieties were examined, including the Pioneer A‐90, Hartz HS‐1, and Iowa State A‐6 lines. Pioneer A‐90 contained 17% stearic acid, had a solid fat index (SFI) of 6.0 at 10°C (50°F) and zero from 21.1 to 40°C (70 to 104°F), and therefore lacked sufficient solids for tub‐type margarine. To improve its plastic range, the Pioneer oil was blended with palm oil, randomized palm oil, or interesterified palm/soy trisaturate basestock. After blending with 10–40% of these components, the high‐stearic acid oil had an SFI profile suitable for soft tube margarine. The A‐6 varieties, 32–38% saturates, showed SFI profiles with sufficient solids at 10°C (50°F) and 21.1°C (70°F) to qualify as a stick‐type margarine oil, but lacked sufficient solids at 33.3°C (92°F); however, after small amounts (2–3%) of cottonseed or soybean hardstocks were added, the A‐6 oils qualified as stick margarine oil. The HS‐1 variety, when blended with small amounts (2–3%) of hardstock, possessed sufficient solids at 10°–33.3°C (50–92°F) to prepare soft tub margarine oil.
A high‐field1H nuclear magnetic resonance study of the minor components in virgin olive oils
Authors: Sacchi R. , Patumi M. , Fontanazza G. , Barone P. , Fiordiponti P. , Mannina L. , Rossi E. , Segre A. L. 
Published: November 2006

AbstractHigh‐field (600 MHz) nuclear magnetic resonance (NMR) spectroscopy was applied to the direct analysis of virgin olive oil. Minor components were studied to assess oil quality and genuineness. Unsaturated and saturated aldehyde resonances, as well as those related to other volatile compounds, were identified in the low‐field region of the spectrum by two‐dimensional techniques. Unsaturated aldehydes can be related to the sensory quality of oils. Other unidentified peaks are due to volatile components, because they disappear after nitrogen fluxing. The statistical analysis performed on the intensity of these peaks in several oil samples, obtained from different olive varieties, allows clustering and identification of oils arising from the same olive variety. Diacylglycerols, linolenic acid, other volatile components, water, acetic acid, phenols, and sterols can be detected simulteneously, suggesting a useful application of high‐field NMR in the authentication and quality assessment of virgin olive oil.