bluuebunny/crossref_metadata_2025_split huggingface dataset:
The cover time of sparse random graphs
Authors: Cooper Colin , Frieze Alan 
Published: December 2006

AbstractWe study the cover time of a random walk on graphs G ∈ Gn,p when
$p={c\log n \over n}, c>1$. We prove that whp, the cover time, is asymptotic to $c\log({c \over c-1})n\log n$. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2007
Randomly generated intersecting hypergraphs II
Authors: Bohman Tom , Frieze Alan , Martin Ryan , Ruszinkó Miklós , Smyth Cliff 
Published: December 2006

AbstractLet c be a positive constant. Suppose that r = o(n5/12) and the members of
$({{[n]}\atop r})$
are chosen sequentially at random to form an intersecting hypergraph ${\cal H}$. We show that whp (A sequence of events ${\cal E}_1,\ldots,{\cal E}_n,\ldots$
is said to occur with high probability (whp) $\lim_{n\to\infty}\Pr({\cal E}_n)=1$.) ${\cal H}$
consists of a simple hypergraph ${\cal S}$
of size Θ(r/n1/3), a distinguished vertex v and all r‐sets that contain v and meet every edge of ${\cal S}$. This is a continuation of the study of such random intersecting systems started in (Bohman et al., Electronic J Combinatorics (2003) R29) where the case r = O(n1/3) was considered. To obtain the stated result we continue to investigate this question in the range ω(n1/3) ≤ r ≤ o(n5/12). © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2007
Roles of the controllability of the event and coping strategies on stress‐related growth in a Turkish sample
Authors: Göral F. Sevinç , Kesimci Aslı , Gençöz Tülin 
Published: December 2006

AbstractThis study intended to examine the roles of the controllability of the stressful life event and coping strategies on the stress‐related personal growth in a Turkish sample. For this 127 undergraduate students reported details of a stressful event that they have recently encountered and rated the stressfulness of this event, following this and considering the stressful event that they had reported, they completed the Ways of Coping Inventory and Stress‐related Growth Scale. The stressful events were categorized into two groups as controllable (e.g. academic achievement anxiety and relationship problems with a friend) and uncontrollable (e.g. serious illness in the family and traffic accident). Consistent with the literature, results revealed that both problem‐focused and emotion‐focused coping strategies resulted in higher levels of stress‐related growth. Furthermore, an interaction between emotion‐focused coping and controllability of the event was observed, which indicated that particularly for the uncontrollable events, the use of emotion‐focused coping led to more stress‐related growth among Turkish participants. These findings and their culture‐specific features were discussed in the light of relevant literature. Copyright © 2006 John Wiley & Sons, Ltd.
A rigorous, engineer‐friendly approach for modelling realistic, composite rotor blades
Authors: Hodges D. H. , Yu W. 
Published: December 2006

AbstractA rigorous approach is presented for the modelling of composite beam structures of the type encountered in wind turbine blades, helicopter rotor blades and the like. The analysis methodology is based on a dimensional reduction of the geometrically nonlinear, three‐dimensional, anisotropic theory of elasticity. Small parameters stemming from the beam‐like geometry of slender structures such as wind turbine blades lead to a splitting of the problem into a (usually) linear, two‐dimensional cross‐sectional analysis and a geometrically exact nonlinear, one‐dimensional beam analysis. The incorporation of such beam analyses into flexible multibody codes presents a unified and powerful approach to the modelling of wind turbines with composite rotor blades. The generality and power of the methodology are illustrated in several examples. Copyright © 2006 John Wiley &Sons, Ltd.
A simple model of host‐parasitoid interaction with host‐feeding
Authors: Yamamura Norio , Yano Eizi 
Published: December 2006

SummaryA simple mathematical model of host‐parasitoid interaction with host‐feeding was presented with special reference to the system of the greenhouse whitefly and the parasitoid Encarsia formosa. In the model, when a parasitoid encounters a host, it has a choice between feeding the host and ovipositing one egg in the host. It was shown that an intermediate value of the feeding ratio of all attacks gives the minimum equilibrium host density and the minimum amplitudes of fluctuation in the densities of the two species. Computer simulations of a modified model with time lags also gave the similar results. The model suggested for natural enemy introduction program that parasitoid species with host‐feeding habits are promising agents for effective controls for pest insects and that the timing of introduction is very important. By an evolutionary analysis, it was shown that the feeding ratio evolves to minimize the host density under natural selection among parasitoids.
Consequences of competition on the time budgets, growth and distributions of three species of terrestrial slugs
Authors: Rollo C. David 
Published: December 2006

SummaryThe behavioural time budgets of two non‐aggressive slugs and one aggreessive species were evaluated in monocultures or in 2‐way combinations in field cages. The seasonal time budgets of L. maximus, A. ater and A. columbianus in monoculture were remarkably similar despite their strong differences in physiological resource allocation. Similarity in physical design and resource utilization appeared to be more important determinants of behaviour.The time budgets showed distinct seasonal patterns associated with underlying physiological demands for reserve accumulation, sperm acquisition and oviposition. A. ater and L. maximus displayed a definite dispersal phase associated with femalephase maturation.In combination, A. ater and A. columbianus had no detectable effect on one another's time budgets. L. maximus disrupted nearly every category of behaviour in these non‐aggressive species, but its own time budget was not significantly different in the monoculture or in the two combinations, except for minor effects on resting and sexual behaviour. L. maximus appeared to be adapted to maximize behavioural disturbance of interspecific competitors while minimizing intraspecific effects.
n‐3 fatty acids and lipoproteins: Comparison of results from human and animal studies
Authors: Harris William S. 
Published: December 2006

AbstractThe impact of n‐3 fatty acids (FA) on blood lipoprotein levels has been examined in many studies over the last 15 yr in both animals and humans. Studies in humans first demonstrated the potent triglyceride‐lowering effect of n‐3 FA, and these were followed up with animal studies to unravel the mechanism of action. This paper reviews the reported effects of n‐3 FA on blood lipoproteins in 72 placebo‐controlled human trials, at least 2 wk in length and providing 7 or less g of n‐3 FA/day. Trials in normolipidemic subjects (triglycerides <2.0 mM; 177 mg/dL) were compared to those in hypertriglyceridemic patients (triglycerides ≥2.0 mM). In the healthy subjects, mean triglyceride levels decreased by 25% (P<0.0001), and total cholesterol (C) levels increased by 2% (P<0.009) due to the combined increases in low density lipoprotein (LDL)‐C (4%,P<0.02) and high density lipoprotein (HDL)‐C (3%,P<0.008). In the patients, triglyceride levels decreased by 28% (P<0.0001), LDL‐C rose by 7% (P<0.0001), but neither total C nor HDL‐C changed significantly. Although the effect on triglyceride levels is also observed in rats and swine, it is rarely seen in mice, rabbits, monkeys, dogs, and hamsters. Whereas n‐3 FA have only a minor impact on lipoprotein C levels in humans, they often markedly lower both total C and HDL‐C levels in animals, especially monkeys. These differences are not widely appreciated and must be taken into account when studying the effects of n‐3 FA on lipoprotein metabolism.
Lipolysis and heterogeneous catalysis. A new concept for expressing the substrate concentration
Authors: Bernard Christine , Buc Jean , Piéroni Gérard 
Published: December 2006

AbstractA new concept is proposed for quantifying the substrate concentration during heterogeneous catalysis of the kind which occurs during lipolysis. The number of molecules of protein (enzyme) adsorbable to the lipid substrate interface per unit of volume was evaluated and defined as a volumetric concentration of protein (enzyme) binding site (PEBS). Using porcine pancreatic lipase (EC 3.1.1.3) as a model enzyme, the maximal PEBS concentration was measured under various assay conditions by determining the saturation of the lipid substrate with the enzyme. Abacuses correlating the lipid substrate concentration (M) with the PEBS concentration (M) under each experimental conditions were used to express the kinetic data in terms of a volumetric concentration of PEBS. Comparisons could thus be made between data obtained with various enzymes and lipid interfaces because they were expressed with the same unit. In the case of pancreatic lipase, using triolein and tributyrylglycerol as substrates,Km values of 2.7 and 7.5 nM PEBS were obtained, respectively, andKD values ranging around 9 nM PEBS were also obtained from Scatchard plots. In addition, the average superficial density of PEBS was found to be 10×1011 molecules·cm−2, which is a value commonly obtained with structural proteins and enzymes adsorbed to an acylglyceride‐water interface, this finding supports the idea that the PEBS concept represents the room in which the protein molecule adsorbs at the lipidic interface.
Mechanism of lower oxidizability of eicosapentaenoate than linoleate in aqueous micelles
Authors: Yazu Kazumasa , Yamamoto Yorihiro , Ukegawa Koji , Niki Etsuo 
Published: December 2006

AbstractThe aerobic oxidation kinetics of methyl eicosapentaenoate (20:5n‐3) and methyl linoleate (18:2n‐6) were compared in homogeneous chlorobenzene solution and in Triton X‐100 aqueous micelles at 37°C. The rate of disappearance of 20:5n‐3 was two times faster than that of 18:2n‐6 in chlorobenzene, while the former was five times slower than the latter in aqueous micelles. It was also observed that ΔO2=Δ18:2n‐6 and ΔO2=2Δ20:5n‐3 in aqueous micelles. In the oxidation of a 1∶1 mixture of 20:5n‐3 and 18:2n‐6 in micelles, the rate of disappearance of 20:5n‐3 was 3.6 times faster than that of 18:2n‐6, and the rate of total substrate disappearance was reduced by a factor of 5 as compared with 18:2n‐6 oxidation. These data suggest that the peroxyl radical derived from 20:5n‐3 is more polar than that from 18:2n‐6, and the former is likely to diffuse from the core to the micelle surface. This lowers the oxidizability for 20:5n‐3 in aqueous micelles by enhancing the termination reaction rate for peroxyl radicals and by reducing the rate of propagation since there may be more 20:5n‐3 peroxyl radicals at the surface than in the micelle core.
The time sequence of the relation between mean crowding and mean density with some population processes
Authors: Hagihara Akio 
Published: December 2006

SummaryThe theories of the stochastic processes are applied to construct mathematical models for describing the processes of population change as an ever changing the distribution of individuals in a space. These models consist of two mathematical expressions which are named the spatial distribution probability function (Qn(t)) and the transition probability function (Pi,n(t)), respectively. The former gives the spatial distribution at any future time. Given an actual spatial distribution at any time, the latter function converts it to the spatial distribution at any future time. According to these models, we discussed the time sequence of the mean crowding‐mean density relation (IwaoandKuno, 1971) in some population processes such as mortality, birth, immigration, growth, and their combined processes.
Competitive ability as a function of sensitivity to the environment I. Competition between Tribolium castaneum and Tribolium confusum in a deteriorating environment
Authors: Lavie Batia 
Published: December 2006

SummaryTribolium castaneum lines selected for high and for low sensitivity to the environment were observed in pure strain culture and in mixed 1∶1 cultures with Tribolium confusm. Since the medium was not refreshed during the experiment, the environment was continuously deteriorating and ultimately both species became extinct. Both time until extinction and total dry weight were used as a measure of competitive ability.All Tribolium castaneum lines showed higher competitive ability than Tribolium confusum. As interference was noted in all the mixed cultures, competition here demonstrates both exploitation and interference.Comparisons between the T. castaneum lines indicates higher competitive ability for lines with shorter developmental time.
A sex ratio theory of gregarious parasitoids
Authors: Suzuki Yoshito , Iwasa Yoh 
Published: December 2006

SummaryA mathematical model is constructed to explain a density‐dependent increase in the progeny sex ratios of gregarious parasitoids. In the model we considered non‐cooperative game between females concerned with their own inclusive fitness. Equilibrium progeny sex ratios of the first and second females ovipositing on the same host are expressed in terms of the probability of double parasitism (p), the ratio of a male to a female in contribution to resource competition (α), the clutch size ratio between the two females (β), the crowding effect on female reproductive success (γ), and the inbreeding coefficient (f). Major predictions from the model are: 1) the progeny sex ratios of both the first and second females increase with p, 2) as β becomes smaller, the progeny sex ratios of the first females decrease, while those of the second females dramatically increases, 3) when a host is attacked by at most two wasps, the sex ratio of the total number of eggs laid on the host does not exceed 0.25. The effects of α and preferential death by female progeny in doubly parasitized hosts are considered as factors responsible for an excess number of males at emergence. Some possible modes of density‐dependent increase in the sex ratios of the overall progeny populations is also discussed on the basis of the present model.
Iσ‐Index, a measure of dispersion of individuals
Authors: Morisita Masaaki 
Published: December 2006

Conclusion and summaryAs the Iσ‐index is neither affected by the mean per sample unit except for regular distribution nor standing on the assumption of any definite type of contagious distribution, it may have the most wide range of application among the ones hitherto deviced for measuring the dispersion of individuals in a population. The relations of the Iσ‐index to ,k of negative binomial distribution and N of binomial distribution as well as the new dispersion index, IB, given in this paper may serve, if necessary, for the analysis of data in the ecological works.
Adrenal analysis for critique of the social stress theory in natural populations of a montane vole
Authors: Tanaka Ryo 
Published: December 2006

SummaryThe vole, Eothenomys smithi, in highlands of Shikoku was studied to disclose ups and downs of adrenal activities under the influence of the breeding level in natural populations. It has proved that the vole's adrenal in both sexes may be much more strongly by rise and fall of the fertility as well as by shift of the age structure in populations than the rat's. Therefore, as for perhaps all kinds of small mammals, we consider necessary to follow a pertinent procedure to avoid thoroughly these sources of error in studies to draw any conclusion for or against theChristian's theory. The present data analysed by such a method failed to afford any confirmative proofs; the fact that the pregnancy rate was increased in parallell to the density is against his view. However, never the whole content of the theory has been invalidated by these results.
Effects of crowding on life history parameters of four green leafhoppers, Nephotettix spp. (Homoptera: Cicadellidae)
Authors: Valle Reynaldo R. , Nakasuji Fusao , Kuno Eizi 
Published: December 2006

SummaryThe effects of intraspecific crowding on the different life history parameters of the three tropical and subtropical green leafhoppers, Nephotettix virescensStål,N. nigropictusDistant and N. malayanusIshihara etKawase, and one temperate species, N. cincticepsUhler, were studied under 25±1°C using the susceptible Japonica rice variety “Nipponbare”. Crowding during the immature stages of the four species prolonged the nymphal developmental period and resulted to smaller adults with reduced fecundity and shorter life span. Similarly, crowding during the adult stage also shortened the life span of both sexes of adults and decreased the fecundity of females of the four species. The effect of crowding during the adult stage was more adverse than the effect of crowding during the immature stages. N. cincticeps seemed more sensitive to crowding even at lower densities whereas the three tropical species were sensitive mostly at higher densities.
The structure of DHA in phospholipid membranes
Authors: Gawrisch Klaus , Eldho Nadukkudy V. , Holte Laura L. 
Published: December 2006

AbstractEarly experiments and molecular simulations of PUFA favored a rigid arrangement of double bonds in U‐shaped or extended conformations such as angle‐iron or helical. Although results of recent solid‐state NMR measurements and molecular simulations have confirmed the existence of these structural motifs, they portray an image of DHA (22∶6n−3) as a highly flexible molecule with rapid transitions between large numbers of conformers on the time scale from picoseconds to hundreds of nanoseconds. The low barriers to torsional rotation about C‐C bonds that link the cis‐locked double bonds with the methylene carbons between them are responsible for this unusual flexibility. Both the amplitude and frequency of motion increase toward the terminal methyl group of DHA.
Influence of different oil‐refining parameters and sampling size on the detection of genetically modified DNA in soybean oil
Authors: Gryson N. , Messens K. , Dewettinck K. 
Published: December 2006

AbstractThe degumming of crude soybean oil causes the removal of DNA, the presence of which is necessary for the detection of genetically modified organisms by polymerase chain reaction (PCR). In both chemical and physical refining processes, physical conditions of the refining steps can vary within a certain range. The extremities in this range may have a different influence on the quality and quantity of the extracted DNA. Therefore, the effects of degumming temperature, degumming time, and the amounts of water and/or acid added during degumming on the DNA quality and amplification were evaluated. Some parameters were shown to have a small influence on the quality of the DNA, but none affected the amplification of soy DNA extracted from the water fractions after the degumming. From the oil fractions, no DNA could be visualized. In this study of the ability of the degumming process to achieve the total removal of DNA from the oil fractions, the sample size during DNA extraction was increased significantly, and amplification of the soylectin genes was attempted. This resulted in a positive amplification of the lectin gene. A possible relation between the size of the test portion, the residual phosphorus content of the sample, and the PCR result is suggested.
Use of Rhizopus delemar lipase as compared with other lipases for determination of sn‐2 fatty acids in triacylglycerol
Authors: Kosugi Yoshitsugu , Oshima Akio , Koike Seiji , Fukatsu Makoto , Minami Keiichi , Miyake Yuko , Masui Kenji 
Published: December 2006

AbstractThe FA composition in the sn‐2 position of TAG is routinely determined after porcine pancreatic lipase hydrolysis. However, the content of saturated FA increased when a pancreatic lipase preparation with higher specific activity was used. Lipase from Rhizopus delemar was selected as a potential replacement lipase for the following reasons: (i) The FA specificity is nearly equivalent in hydrolysis activity toward FA such as lauric, myristic, palmitic, palmitoleic, stearic, oleic, linoleic, and α‐linolenic acids; and (ii) lipase from R. delemar hydrolyzes fatty acyl residues at the sn‐1,3 positions of TAG. Acyl migration products were present at less than 0.8% in lipase hydrolysates containing 6–14% of sn‐2 MAG. A reproducibility CV of less than 5% was obtained in a collaborative study in which the compositions of the main FA at the sn‐2 position in olive oil were determined using lipase from R. delemar.
Effects of flour sources on acrylamide formation and oil uptake in fried batters
Authors: Shih F. F. , Boué S. M. , Daigle K. W. , Shih B. Y. 
Published: December 2006

AbstractFood batters were formulated using flours of long‐grain rice, waxy rice, wheat, or corn. Acrylamide and oil analyses were conducted for the flour and the corresponding fried batter. During frying, the formation of acrylamide ranged from 82 ng/g for the long‐grain rice batter to 263 ng/g for the corn batter. Oil uptake ranged from 21.4% for the long‐grain rice batter to 47.3% for the wheat batter. The incorporation of 5% pregelatinized rice flour and 1.5–3.0% milk as functional additives into the long‐grain rice batter only slightly increased the acrylamide and oil contents.
Antioxidant activity of tea theaflavins and methylated catechins in canola oil
Authors: Su Ya‐Lun , Xu Jin‐Ze , Ng Chi Ho , Leung Lai Kwok , Huang Yu , Chen Zhen‐Yu 
Published: December 2006

AbstractThe present study examined the antioxidant activity of black tea theaflavins and catechin derivatives in canola oil. Oxidation was conducted at 95°C by monitoring the oxygen consumption and decreases in the linoleic and α‐linolenic acids of canola oil. All were tested at a concentration of 0.5 mM. Catechins, including (−)‐epicatechin, (−)‐epicatechin gallate, (−)‐epigallocatechin, and (−)‐epigallocatechin gallate (EGCG), were more effective than theaflavins, namely, theaflavin‐1, theaflavin‐3‐gallate, theaflavin‐3′‐gallate, and theaflavin‐3,3′‐digallate (TF3), against the lipid oxidation of canola oil. Among the four theaflavins, TF3 was the most effective, whereas among the four catechins, FGCG was the most potent. Under the same conditions, all theaflavins and catechins were more powerful than BHT as an antioxidant in heated canola.oil. Little or no difference in antioxidant activity was observed between each catechin and epimer pair. Methylation of the 3′‐OH led to a significant loss of antioxidant activity of the catechins.
Supercritical fluid extraction of jojoba oil
Authors: Salgin Uĝur , Çalimli Ayla , Zühtü Uysal Bekir 
Published: December 2006

AbstractSupercritical fluid extraction of jojoba oil from Simmondsia chinensis seeds using CO2 as the solvent is presented in this study. The effects of process parameters such as pressure and temperature of extraction, particle size of jojoba seeds, flow rate of CO2, and concentration of entrainer (hexane) on the extraction yield were examined. Increases in the supercritical CO2 flow rate, temperature, and pressure generally improved the performance. The extraction yield increased as the particle size decreased, indicating the importance of decreasing intraparticle diffusional resistance. The maximum extraction yield obtained was 50.6 wt% with a 0.23‐mm particle size and a 2 mL/min CO2 flow rate at 90°C and 600 bar. Use of an entrainer at a concentration of 5 vol% improved the yield to 52.2 wt% for the same particle size and also enabled the use of relatively lower pressure and temperature, i.e., 300 bar and 70°C.