bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Spanish grapevine cultivar diversity using sequence-tagged microsatellite site markers
Authors: Martín J P , Borrego J , Cabello F , Ortiz J M
Published: February 2003

A broad germplasm bank collection containing most of the autochthonous Spanish grapevine cultivars was analyzed using six sequence-tagged microsatellite site (STMS) loci: VVS2, VVMD5, VVMD7, ssrVrZAG47, ssrVrZAG62, and ssrVrZAG79. The number of alleles obtained ranged from 9 in ssrVrZAG47 to 13 in VVS2, and the observed genotypes per locus varied between 24 (ssrVrZAG47) and 41 (VVSS2). A total of 57 unique genotypes were obtained considering all 6 loci, and 40 varieties presented at least 1 of these specific genotypes. The genotypic combinations for the 6 loci have generated 163 different profiles in the 176 cultivars. Ten pairs of accessions and one group of four Garnacha's cultivars can not be differentiated. The observed heterozygosity varied between 75.6 (VVMD7) and 90.9% (VVMD5), without significant differences from the expected values for any loci. The VVMD5 locus was the most informative, and also showed the highest discrimination power. The cumulative discrimination power for all six loci was practically 1; however, in fact, these STMS loci have differentiated only about 93% of the accessions, probably owing to high relatedness of the plant material. Usefulness of this STMS set for characterization of a Spanish grapevine collection is emphasized, as well as the elaboration of databases with these molecular markers.Key words: Vitis vinifera L., STMS markers, genotype identification, grapevine synonymies, germplasm bank.
The correlation between rDNA copy number and genome size in eukaryotes
Authors: Prokopowich Cheryl D , Gregory T Ryan , Crease Teresa J
Published: February 2003

Both rDNA gene multiplicity and genome size vary widely among eukaryotes. For some time, there has been debate regarding any possible relationship between these two parameters. The present study uses data on genome size and rDNA copy number for 162 species of plants and animals to test the association between genome size and rDNA copy number, and provides the first convincing evidence of a strong positive relationship between the two within and among these two groups of organisms. No simple explanations exist for this relationship, but it is nevertheless of clear relevance from both practical and theoretical perspectives.Key words: rRNA genes, C value, genome size.
Characterization of microsatellites in wild and sweet cherry (Prunus avium L.)  markers for individual identification and reproductive processes
Authors: Schueler Silvio , Tusch Alexandra , Schuster Mirko , Ziegenhagen Birgit
Published: February 2003

Nuclear microsatellites were characterized in Prunus avium and validated as markers for individual and cultivar identification, as well as for studies of pollen- and seed-mediated gene flow. We used 20 primer pairs from a simple sequence repeat (SSR) library of Prunus persica and identified 7 loci harboring polymorphic microsatellite sequences in P. avium. In a natural population of 75 wild cherry trees, the number of alleles per locus ranged from 4 to 9 and expected heterozygosity from 0.39 to 0.77. The variability of the SSR markers allowed an unambiguous identification of individual trees and potential root suckers. Additionally, we analyzed 13 sweet cherry cultivars and differentiated 12 of them. An exclusion probability of 0.984 was calculated, which indicates that the seven loci are suitable markers for paternity analysis. The woody endocarp was successfully used for resolution of all microsatellite loci and exhibited the same multilocus genotype as the mother tree, as shown in a single seed progeny. Hence, SSR fingerprinting of the purely maternal endocarp was also successful in this Prunus species, allowing the identification of the mother tree of the dispersed seeds. The linkage of microsatellite loci with PCR-amplified alleles of the self-incompatibility locus was tested in two full-sib families of sweet cherry cultivars. From low recombination frequencies, we inferred that two loci are linked with the S locus. The present study provides markers that will significantly facilitate studies of spatial genetic variation and gene flow in wild cherry, as well as breeding programs in sweet cherry.Key words: Prunus, SSR, S alleles, endocarp, seed dispersal, cultivar identification.
Estimation régionale par la méthode de l'analyse canonique des corrélations: comparaison des types de variables hydrologiques
Authors: Haché Mario , Ouarda Taha B.M.J , Bruneau Pierre , Bobée Bernard
Published: February 2003

It is often necessary to estimate extreme events at sites where little or no hydrometric data are available. In such cases, one may use a regional estimation procedure, utilizing data available from other sites in the same hydrologic region. In general, a regional flood frequency procedure consists of two steps: determination of hydrologically homogeneous region and regional estimation. This paper presents the development of a regional flood frequency procedure based on canonical correlation analysis and multiple regression: (i) the canonical correlation analysis allows us to link a set of hydrological variables and a set of physiographical and (or) meteorological variables and, therefore, to determine the hydrological neighborhood of an ungauged site; (ii) the multiple regression allows us to transfer data from sites of the homogeneous region to the target site. The developed methodology was applied to the Saint-Maurice river region (Quebec, Canada). Using a jackknife procedure, several pairs of hydrological variables were compared to identify the most appropriate grouping. Key words: regionalization, frequency analysis, canonical correlation analysis, multiple regression.
Observation et prédiction d'une brèche de rupture dans une digue submergée
Authors: Marche Claude , Fuamba Musandji
Published: February 2003

The failure of a submerged dyke is very often due to the erosion of the materials that form the work. The erosion process continues until a hydro-geotechnical equilibrium is developed between the spillover and the dyke. An experimental laboratory study of a submerged dyke is presented in this article to describe and analyse this erosion process, as well as its consequences. A method predicting the resulting breach, based on a new hydro-sedimentological model ERODE, has been applied on the test dyke, and encouraging results have been found regarding the progression and the stabilisation of the phenomenon.Key words: submerged dyke, breach, discharge at failure, erosion, prediction.[Journal translation]
Sélectivité des écailles de cacao pour l'enlèvement des métaux des effluents de décontamination de sols
Authors: Meunier Nathalie , Blais Jean-Francois , Tyagi Rajeshwar Dayal
Published: February 2003

Washing using inorganic acids is a common method for treatment of metal-polluted soils. Metals solubilized during soil washing have to be removed from washing solutions (leachates). The purpose of this research was to evaluate the efficiency and the selectivity of cocoa shells to adsorb metals contained in acid leachates of soil decontamination. Shake flask experiments were done using 15 g/L of cocoa shells and a doped (addition of 100 and 300 mg metal/L) acid leachate (pHi = 2.4) using 1 or 10 metal salts. These tests have revealed that this natural sorbent is particularly efficient to remove lead and, to a lesser degree, copper from solution. A maximal lead concentration of 17 900 mg/kg, corresponding to 75 % of lead removal, has been adsorbed on cocoa shells during tests using a soil leachate doped with 300 mg Pb/L. This research also showed that cocoa shell selectivity generally follows this order: Pb >> Cu >> Fe > Al > Cr >> Co > Zn > Mn > Cd > Ni. Kinetic studies over a 24-h period have indicated that the equilibrium of metals adsorption is almost reached in the first 2 h of contact. Moreover, metal uptake on cocoa shells is controlled by an ion-exchange mechanism involving magnesium and potassium release from the adsorbent. Finally, cocoa shells are a promising natural adsorbent for the treatment of metal-contaminated acid effluents and particularly for the removal of lead from these solutions. Key words: adsorption, metals, lead, cocoa shells, leachate, soils.
Spatial and temporal variation of drinking water quality in ten small Quebec utilities
Authors: Coulibaly H D , Rodriguez M J
Published: February 2003

A comparative study relating to distributed water quality was undertaken in 10 small municipal drinking water utilities in Quebec. All of these utilities apply direct chlorination to surface water or groundwater under the direct influence of surface water without any previous treatment. These utilities were divided into two groups: four utilities that had never or rarely served water violating the provincial drinking water microbiological standards (relating to fecal and (or) total coliform bacteria) and six utilities that very often infringed upon said standards. The objective of this study was to identify key parameters responsible for the differences between the two groups of utilities, to explore the capacity of studied utilities to simultaneously and effectively handle the acute disease risk associated with microorganisms and the chronic health hazard linked to chlorination by-products and to identify the parameters upon which it may be possible to act to achieve better water quality in each of the two utility groups. The study includes comparisons of characteristics of water quality at the source, chlorination conditions in the plant, and water quality from the entrance to the extremity of the distribution system. Results show that the differences between the two groups of utilities are associated essentially with maintained chlorine residuals and heterotrophic plate count bacteria populations in corresponding distribution systems and, to a lesser extent, to the applied chlorine doses. Subsequent multivariate analyses allowed identification of variables (i.e., factors) upon which utility managers may act to improve the quality of distributed water in each group of utilities. For the group of utilities that had very little or no violation, these factors are related to disinfection levels, whereas for the group that often violated quality standards, raw water natural organic matter content reduction through source water protection and raised chlorine doses and residuals appear to be the factors that may lead to better microbiological quality of distributed water. Key words: drinking water, water quality, distribution systems, small utilities, Quebec.
Mesh size selection in a soil-biosphere-atmosphere transfer model
Authors: Mangeney A , Aubert D , Demarty J , Ottlé C , Braud I
Published: February 2003

The aim of this paper is to show the impacts of the vertical discretization in a physical soil numerical model on the calculation of the heat and mass transfer equations. The Simple Soil Plant Atmosphere Transfer (SISPAT) model was used in this study. It solves the coupled equations of mass and energy transfers in the soil and can deal with several horizons for vertically non-homogeneous soils. A series of numerical experiments have been performed to assess the influence of the vertical resolution grid on the simulation of the heat and water transfers using the SISPAT model in a one horizon configuration (homogeneous soil). In the studied case, a minimum of 20 layers has been found for a single 1.4 m thick horizon. Based on this analysis, numerical tests have been performed using SISPAT in a four horizons configuration. Key words: soilatmosphere exchanges, numerical model, vertical resolution, heat and mass transfer.
Control of pyrimidine formation inPseudomonasputidaATCC 17536
Authors: Santiago Manuel F , West Thomas P
Published: February 2003

The regulation of de novo pyrimidine biosynthesis in Pseudomonas putida ATCC 17536 by pyrimidines was explored. The pathway enzyme activities were higher in glucose-grown cells than in succinate-grown cells, indicating catabolite repression by succinate. In P. putida cells grown on succinate as a carbon source, only aspartate transcarbamoylase activity was greatly diminished by uracil supplementation. When glucose was the carbon source, orotic acid supplementation significantly decreased orotate phosphoribosyltransferase and orotidine 5'-monophosphate (OMP) decarboxylase activities. Uracil auxotrophs, deficient for dihydroorotase activity or with reduced phosphoribosyltransferase activity, were isolated. After pyrimidine limitation of both auxotrophs, the greatest derepression of enzyme activity was observed for OMP decarboxylase independent of carbon source. Orotic acid induced both phosphoribosyltransferase and decarboxylase activities in glucose-grown cells of the dihydroorotase-deficient strain. Regulation at the transcriptional level of de novo pyrimidine biosynthetic enzyme synthesis in P. putida ATCC 17536 was observed, which contrasts with previous observations.Key words: pyrimidine biosynthesis, regulation, auxotrophs, induction, Pseudomonas.
Water activity, temperature, and pH effects on growth of the biocontrol agentPantoea agglomeransCPA-2
Authors: Costa E , Usall J , Teixidó N , Delgado J , Viñas I
Published: February 2003

The growth response of the biocontrol agent Pantoea agglomerans to changes in water activity (aw), temperature, and pH was determined in vitro in nutrient yeast extract-sucrose medium. The minimum temperature at which P. agglomerans was able to grow was 267272 kelvins (6 to 1°C), and growth of P. agglomerans did not change at varying pH levels (4.58.6). The minimum awfor growth was 0.96 in media modified with glycerol and 0.95 in media modified with NaCl or glucose. Solute used to reduce water activity had a great influence on bacterial growth, especially at unfavourable conditions (e.g., low pH or temperature). NaCl stimulated bacterial growth under optimum temperatures but inhibited it under unfavourable pH conditions (4.5 or 8.6). In contrast, the presence of glucose in the medium allowed P. agglomerans to grow over a broad range of temperature (342°C) or pH (58.6) regimes. This study has defined the range of environmental conditions (aw, pH, and temperature) over which the bacteria may be developed for biological control of postharvest diseases.Key words: biocontrol, ecophysiology response, stress.
Characterization of a clinicalVibrio choleraeO139 isolate from Mexico
Authors: Parveen Salina , Farrah Samuel R , Gonzalez-Bonilla Celia , Zamudio Altagracia V , Tamplin Mark L
Published: February 2003

Pathogenic strains of Vibrio cholerae O139 possess the cholera toxin A subunit (ctxA) gene as well as the gene for toxin co-regulated pili (tcpA). We report the isolation of a ctxA-negative, tcpA-negative V. cholerae O139 strain (INDRE1) from a patient in Mexico diagnosed with gastrointestinal illness. Certain phenotypic characteristics of this strain were identical to those of V. cholerae O1 biotype El Tor. Unlike ctxA-positive V. cholerae O139 strains, this strain was sensitive to a wide panel of antibiotics, including ampicillin, chloramphenicol, ciprofloxacin, gentamicin, furazolidone, nalidixic acid, nitrofurantoin, tetracycline, trimethoprim-sulfamethoxazole, and streptomycin, but was resistant to polymyxin B. Ribotype and pulsed-field gel electrophoresis profiles of INDRE1 differed from those of ctxA-positive V. cholerae O139 and other V. cholerae strains. Phenotypic characteristics of the Mexico strain were similar to those reported for V. cholerae O139 isolates from Argentina and Sri Lanka.Key words: Vibrio cholerae O139, cholera toxin, ctxA, tcpA.
Pressor responsiveness to angiotensin in soy-fed spontaneously hypertensive rats
Authors: Martin Douglas S , Williams J L , Breitkopf Nikolai P , Eyster Kathleen M
Published: February 2003

Dietary soy may attenuate the development of arterial hypertension. In addition, some soy-containing foods exhibit angiotensin-converting enzyme (ACE) inhibitory properties. Accordingly, we tested the hypothesis that ACE inhibition contributes to the antihypertensive effect of dietary soy. Mean arterial blood pressure (MAP) was recorded from conscious spontaneously hypertensive rats (SHR) at least 24 h after the implantation of catheters. Cumulative doseresponse curves to intravenous angiotensin I (AI) (5100 ng·kg1·min1) and angiotensin II (AII) (120 ng·kg1·min1) were constructed for male, sham-operated female, and ovariectomized female (OVX) SHR that were maintained on either casein or soy diets. The soy diet was associated with a significant reduction in baseline MAP in the OVX SHR (~20 mmHg, 1 mmHg = 133.322 Pa). AI and AII infusions caused graded increases in MAP in all groups. However, there was no significant attenuation of the pressor responses to AI in the soy-fed SHR. Conversely, we observed a significant rightward displacement of the AII doseresponse curves in the soy-fed sham-operated and OVX SHR. We conclude that ACE inhibition does not account for the antihypertensive effect of dietary soy in mature SHR.Key words: dietary soy, hypertension, SHR, angiotensin I, angiotensin II.
Neuropeptide Y: a new mediator linking sympathetic nerves, blood vessels and immune system?
Authors: Zukowska Zofia , Pons Jennifer , Lee Edward W , Li Lijun
Published: February 2003

Neuropeptide Y (NPY136), a sympathetic cotransmitter and neurohormone, has pleiotropic activities ranging from the control of obesity to anxiolysis and cardiovascular function. Its actions are mediated by multiple Gi/o-coupled receptors (Y1Y5) and modulated by dipeptidyl peptidase IV (DPPIV/cd26), which inactivates NPY's Y1-agonistic activity but generates the Y2and Y5-agonist, NPY336. Released by sympathetic activity, NPY is a major mediator of stress, responsible for prolonged vasoconstriction via Y1receptors. Y1receptors also mediate NPY's potent vascular growth-promoting activity leading in vivo in rodents to neointima formation. This and the association of a polymorphism of the NPY signal peptide with increased lipidemia and carotid artery thickening in humans strongly suggest NPY's role in atherosclerosis. NPY and DPPIV/cd26 are also coexpressed in the endothelium, where the peptide activates angiogenesis. A similar system exists in immune cells, where NPY and DPPIV/cd26 are coactivated and involved in the modulation of cytokine release and immune cell functions. Thus, NPY, both a messenger and a modulator for all three systems, is poised to play an important regulatory role facilitating interactions among sympathetic, vascular and immune systems in diverse pathophysiological conditions such as hypertension, atherosclerosis and stress-related alterations of immunity.Key words: neuropeptide Y, immune system, sympathetic nerves, cardiovascular system.
Melatonin and thermoregulation in ectothermic vertebrates: a review
Authors: Lutterschmidt Deborah I , Lutterschmidt William I , Hutchison Victor H
Published: February 2003

Precise behavioral thermoregulation is well documented in many ectothermic vertebrates. However, many complexities involving the influence of the pineal gland and melatonin (MEL) on thermoregulatory behavior, and thus body temperature (Tb), remain unresolved. Although MEL is commonly considered to decrease Tb in both endotherms and ectotherms, several ectothermic species do not modulate Tb in response to MEL. Furthermore, it is not yet clear how MEL integrates thermoregulatory behavior with environmental stimuli or how it modulates Tb. Some inferences about MEL action in endotherms are not applicable to ectotherms. Changes in ectothermic Tb are mediated primarily through behavioral modulation (not physiological modulation as in endotherms). Thus, the most likely mechanism underlying MEL's actions on ectothermic Tb is adjustment of the temperature set point in the hypothalamus. We provide a review of the literature addressing the effects of MEL on thermoregulatory behavior in ectothermic vertebrates. We also discuss mechanisms underlying MEL's influence on physiological and behavioral processes in ectotherms and hypotheses regarding interspecific differences in pineal complex and MEL function.
Does low fecundity reflect kin recognition and inbreeding avoidance in the mandarin vole (Microtus mandarinus)?
Authors: Fadao Tai , Ruyong Sun , Tingzheng Wang
Published: February 2003

The effects of kin recognition on estrus and breeding in mandarin voles (Microtus mandarinus) were investigated in the laboratory using a cross-fostering method. Nonsiblings reared apart produced significantly more litters than siblings or nonsiblings reared together. These results may support the hypothesis that familiarity through association before weaning plays an important role in kin recognition. On the other hand, nonsiblings reared apart produced significantly more litters than siblings reared apart. Furthermore, there was no significant difference in number of litters between siblings reared apart and siblings reared together. These observations show that phenotype-matching mechanisms of kin recognition may operate in conjunction with familiarity in kin recognition in this species. Through observing the vaginal cytology of female mandarin voles paired with different males in different rearing conditions, it was found that females paired with familiar males (through association before weaning) produced significantly fewer estrous smears than females paired with unfamiliar males (reared by different parents before weaning), regardless of genetic relatedness. Thus, using vaginal cytology as an indicator of estrus, it was found that familiarity through association before weaning may retard the first estrus of female mandarin voles.
Social, maternal, and environmental influences on reproductive success in female Alpine marmots (Marmota marmota)
Authors: King Wendy J , Allainé Dominique
Published: February 2003

We examined the social, maternal, and environmental factors affecting the reproductive success of female Alpine marmots (Marmota marmota) during 8 years in the French Alps. Successful production of juveniles was almost entirely limited to dominant females. Production of juveniles increased with maternal body condition and experience. Female body condition was positively correlated with body mass and negatively correlated with dominant-male takeovers in spring, while experience increased with age. We found little evidence for a pregnancy block with takeover of dominant males because male replacement occurred mostly after mid-May, when juveniles were susceptible to infanticide. Production of yearlings depended on the number of juveniles produced, dominant-male takeovers in summer, and exposure of the site. We found no significant influence of group size or composition on production of yearlings. Climatic conditions varied little and had no measurable effect on reproduction. Social factors such as female dominance and dominant-male takeovers that could lead to infanticide have a strong effect on female reproductive success in Alpine marmots.
Pea aphid,Acyrthosiphon pisum, cornicle ontogeny as an adaptation to differential predation risk
Authors: Mondor Edward B , Roitberg Bernard D
Published: February 2003

Aphids possess unique anatomical structures called cornicles through which a defensive secretion containing alarm pheromone is often emitted when a predator attacks an aphid. The levels of alarm pheromone in cornicle droplets from the pea aphid, Acyrthosiphon pisum (Harris), vary considerably during development; however, it is not clear how the length of the cornicle changes during ontogeny. The length of the cornicle relative to the lengths of other body structures may have profound effects on aphid defense and alarm signal diffusion. Using previously published morphological measurements of pea aphids and observing interactions between pea aphids and multicolored Asian ladybird beetles, Harmonia axyridis Pallas, it was observed that pea aphid cornicles elongate proportionally more than other body parts during the first four instars, when alarm-pheromone levels have peaked, than during the fifth (adult) instar, when pheromone levels decline. Pea aphids also are more likely to emit cornicle droplets and daub them onto a predator when the cornicles are undergoing such rapid growth. We suggest that because of a high risk of predation, rapid cornicle growth in juveniles has evolved both for individual defense and for the inclusive fitness benefits of alarm signaling.
Age determination of mysticete whales using210Pb/226Ra disequilibria
Authors: Kastelle Craig R , Shelden Kim EW , Kimura Daniel K
Published: February 2003

Accurate age determination is fundamental to the study of population structure and individual growth rates of mysticete whales. Here the disequilibrium between210Pb and226Ra in the tympanic bullae of two mysticete whale species was investigated for use as a chronometer. Radiometric ageing depends upon accumulation of the naturally occurring radionuclide226Ra (exclusive of other238U decay-chain members) in the bullae and subsequent retention of its progeny210Pb. Ages are determined from the210Pb/226Ra activity ratio. Samples were obtained from five gray whales (Eschrichtius robustus) with lengths of 4.5 (a neonate), 7.8, 8.7, 10, and 11.5 m, and two bowhead whales (Balaena mysticetus) with lengths of 12.9 and 17.4 m. In gray whales, radiometric ages were estimated in the three largest whales. In the neonate, the210Pb/226Ra ratio was above one and was not usable. The 7.8-m gray whale was used to determine the initial210Pb/226Ra ratio required for age determination. We propose a theory of gray whale bullae growth starting at the fetal stage with an open system (with a210Pb/226Ra > 1 and a fast growth rate), which transitions by 1 year old to a closed system (with a210Pb/226Ra << 1 and a slow growth rate). In both bowhead whales, radiometric age could not be estimated because the210Pb/226Ra ratio was above one. The excess210Pb in these bullae samples was likely accumulated from the whales' environment via prey, or in the case of the neonate gray whale, across the placental boundary. Our results indicate that the underlying assumptions of the210Pb/226Ra radiometric ageing method may not hold true in bowhead whales. Successful application of this method to bowhead whales is therefore doubtful.
Reproductive behaviour of spadefoot toads (Pelobates fuscus): daily sex ratios and males' tactics, ages, and physical condition
Authors: Eggert Christophe , Guyétant Robert
Published: February 2003

In anuran competition over mates, disadvantaged (i.e., less competitive) males are generally known to be the smallest ones, but ages of those males have rarely been documented. In the context of a high level of male competition for mates, disadvantaged males were expected to use alternative mating tactics. To test for alternative tactics in a territorial toad (the spadefoot toad, Pelobates fuscus, Pelobatidae), daily breeding migration patterns were observed during 3 consecutive years. Relationships between migration pattern, operational sex ratio (OSR), and male's age (inferred from skeletochronological analysis), size, and mass were analysed. During 2 of the study years, OSRs were highly male-biased at the beginning of the breeding season and then gradually decreased when male numbers increased. Males with a low body condition index (CI) tend to arrive later and to lose relatively more mass than males with a higher CI. There was a negative relationship between percent mass loss per day and CI as well as length of stay in the breeding area, which suggests that a high energetic cost tactic was adopted by males with a higher CI. A negative relationship between length of stay and age was also observed. We conclude that based on competition for mates, male P. fuscus seem to adopt reproductive behaviour that differs according to body condition and age.
Predator diet cues and the assessment of predation risk by juvenile brook charr: do diet cues enhance survival?
Authors: Mirza Reehan S , Chivers Douglas P
Published: February 2003

Recent studies have shown that predator diet cues provide important information that prey animals can use to assess predation risk. Predator-naïve prey animals may even learn to recognize unknown predators when they detect conspecific cues in the predator's diet. We examined the importance of predator diet cues in the responses of juvenile brook charr (Salvelinus fontinalis) to chemical cues of predators. In our first experiment, we showed that charr respond to chemical cues of adult yellow perch (Perca flavescens) that were fed a diet of either brook charr or rainbow trout (Oncorhynchus mykiss), but not to perch fed a diet of brook stickleback (Culaea inconstans). Responses to diet cues from perch fed both charr and trout may indicate that charr are responding to evolutionarily conserved salmonid alarm cues in the predator's diet. In a second experiment, we exposed charr to chemical cues from predatory northern pike (Esox lucius) that were fed charr, trout, or stickleback. Live-predation trials revealed that charr exposed to diet cues from pike fed salmonids exhibited higher survival than charr exposed to diet cues from pike fed a non-salmonid. These results are the first to document a survival benefit for prey exhibiting behavioural responses to predator diet cues.
Observations on the agonistic behavior of the swimming crab Charybdis longicollis Leene infected by the rhizocephalan barnacle Heterosaccus dollfusi Boschma
Authors: Innocenti Gianna , Pinter Noa , Galil Bella S
Published: February 2003

The effects of the invasive rhizocephalan parasite Heterosaccus dollfusi on the agonistic behavior of the invasive swimming crab Charybdis longicollis were quantitatively analyzed under standardized conditions. The behavior of uninfected male crabs contained more aggressive elements than that of uninfected females. In encounters between infected males, markedly fewer and less aggressive elements were displayed than in encounters between uninfected males, whereas in encounters between infected females, more aggressive elements were displayed than in encounters between uninfected females. It is suggested that the presence of the parasite reduces belligerence in male crabs, possibly to avoid injury and to enhance the life expectancy of host and parasite.
ASPECTS OF DUALITY IN NODAL LIQUIDS
Authors: MAVROMATOS NICK E. , SARKAR SARBEN
Published: February 2003

Starting from a microscopic t–J like model and a SU(2) spin-charge separation ansatz, a relativistic continuum gauge Lagrangian is obtained in the vicinity of a nodal point of the Fermi surface. The excitations in the pseudogap phase are described by topological excitations in the dual model which has a Z2 global symmetry due to the effect of instantons. Confinement of spinon and holons emerge from this picture. The adjoint and fundamental strings are associated with stripes. As the spin gap decreases a local Z2 symmetry emerges.
POSSIBLE OBSERVATION OF TRANSFORMATION OF ELEMENTS IN CAVITATED WATER
Authors: CARDONE FABIO , MIGNANI ROBERTO
Published: February 2003

We carried out two experiments of cavitating water. In the first one, we subjected to cavitation a sample of bidistilled and de-ionized water by means of new type of sonotrode with a very long working time (> 30 minutes). We analyzed the cavitated water by three different procedures (mass atomic absorption, cyclotron spectrometry and mass spectrometry). The analysis was confined to the stable chemical elements. We found relevant changes in the concentrations of the elements in the cavitated sample. In the second experiment, the water was cavitated by a standard sonotrode four times, and the cavitated water after each cavitation run was analyzed by means of a spectrometer in the mass range 210 < M < 270. Evidence was found for an excess of identified masses in the transuranic region. Our results are similar, in many respects, to those obtained by Urutskoev et al. in the experimental study of electric explosion of metal foils in water. A possible connection with the recent Oak Ridge experiment on nuclear fusion induced by cavitation is also hypotesized.
ONE DIMENSIONAL NATURE OF IONIC CONDUCTIVITY IN SELF-FLUX GROWN RbTiOPO4 SINGLE CRYSTALS
Authors: KANNAN C. V. , GANESAMOORTHY S. , SUBRAMANIAN C. , RAMASAMY P.
Published: February 2003

The ionic conductivity of self-flux grown RbTiOPO 4 single crystal along the crystallographic a, b and c (polar) axes in the frequency range 100 Hz–10 MHz and in the temperature range 300–1140 K has been studied. The measured activation energy indicates the existence of super ionic conduction behavior in RTP crystals and also reveals that the DC electrical conduction and dielectric polarization are governed by the same mechanism. Complex impedance measurement shows the existence of non-Debye type of relaxation in the crystals.
A COMPREHENSIVE STUDY OF THE ELECTRONIC STRUCTURE OF BOROCARBIDES BY XPS TECHNIQUE
Authors: KUMARI KAMLESH , SINGHAL R. K. , GARG K. B. , HEINONEN M. , LEIRO J. , NORBLAD PER , GUPTA L. C.
Published: February 2003

Polycrystalline samples of YNi 2 B 2 C and magnetic ErNi 2 B 2 C prepared by arc melting technique have been investigated. Resistivity and magnetization measurements yield superconducting transition temperatures for the two samples of ~ 15 K and ~ 11 K respectively. Core level spectroscopic studies on C (1s), B (1s), Ni (2p), Er (4d) and Y (3d) as well as valence band measurements were performed in order to investigate the electronic structure. The results are interpreted to deduce the valence of Y, Er and Ni. Ni is found to exist in 2+ and y in 3+ valence state. The Er spectra indicate that Er may either be in an intermediate valence state or some minor impurity phase.
DETERMINATION OF THE GROUND-STATE GEOMETRIES OF COPPER CLUSTERS BY SIMULATED ANNEALING WITHIN AN EQUIVALENT CRYSTAL APPROACH
Authors: BANERJEA AMITAVA , DATTA RADHIKA PROSAD , MOOKERJEE ABHIJIT , BHATTACHARYYA A. K.
Published: February 2003

We determine the lowest energy structures of small (11–20 atoms) copper clusters. The semi-empirical Equivalent Crystal Theory (ECT) is used in conjunction with the Metropolis Monte Carlo algorithm to determine the equilibrium geometry of each cluster via simulated annealing. The optimum structures of the clusters in this size range are found to be derived from icosahedral structures. The 13-atom cluster is an icosahedron and the 19-atom is a double-icosahedron. The other sizes show structures related to these. The 11-atom clusters, however, show somewhat different structures. We propose the ECT as an efficient tool for developing starting structures for more chemically accurate, first principles and therefore computationally very demanding, approaches.
EFFECT OF ALLOYING ON THE ELECTRONIC STRUCTURE AND MAGNETIC PROPERTIES OF AgFe, AuFeand CuFe
Authors: HUDA AIN-UL , AHMED MESBAHUDDIN , HALDER AMAL , MOOKERJEE A.
Published: February 2003

We use the self-consistent, augmented space recursion technique to study the electronic structure and magnetic properties of alloys of the transition metal Fe with the noble metals Cu, Ag and Au. We analyze the effect of hybridization between the constituent bands on the electronic and magnetic properties.
TEMPERATURE AND FIELD VARIATION OF AC SUSCEPTIBILITY ON Mn DOPED YBa2Cu3O7-δ SUPERCONDUCTOR
Authors: ISAAC SAMUEL E. , SESHU BAI V.
Published: February 2003

Temperature variation of AC susceptibility has been measured on YBa 2( Cu 1 - x- Mn x)3 O 7-δ samples with x values 0, 0.01, 0.015, 0.02, 0.025, 0.035 and 0.05, YBa 2( Cu 0.075 Fe 0.025)3 O 7-δ and YBa 2( Cu 0.075 Ni 0.025)3 O 7-δ samples in the temperature range from 10 to 120 K. The weak link (inter-granular) and granular responses are distinctly pronounced at the studied fields of 0.2 to 30 Oe. The temperature variation of weak link critical current density Jcw(T) indicates the inter-granular coupling to be of superconductor-insulator-superconductor (SIS) type. The weak link AC loss calculated from the imaginary part of the AC susceptibility χ′′(T) is found to exhibit a power relation with temperature, with an average exponent value of 1.96. Field variation of AC susceptibility measured at 50 K and 77 K were well modelled with Kim's relation and the Jcw at 50 K and 77 K were estimated from the fit parameters.
HIGH TEMPERATURE SUPERCONDUCTIVITY AND BERRY PHASE
Authors: BASU B. , BANDYOPADHYAY P. , PAL D.
Published: February 2003

We have analyzed the mechanism of high Tcsuperconductivity from the viewpoint of chirality and Berry phase. It is observed that spin pairing and charge pairing is caused by a gauge force generated by magnetic flux quanta attached to them. Different phase structures associated with high Tcsuperconductivity have been studied from an analysis of the renormalization group equation involving the Berry phase factor μ. It is found that there are two crossovers above the superconducting temperature Tc, one corresponding to the glass phase and the other represents spin gap phase. However, the spin gap temperature [Formula: see text] is found to be dependent on Tcand [Formula: see text] shows a universal behaviour with respect to the hole doping δ/δ0with δ0being the optimal doping rate.
THEORETICAL STUDY OF THE COHERENT LIGHT BACKSCATTERING BY RANDOM MEDIA
Authors: BRODSKY A. , BURGESS L.
Published: February 2003

A theoretical study of coherent backscattering of light by semi-infinite disordered media is presented. Particular attention is devoted to the case when the light wavelength is larger than the characteristic dimensions of non-uniformities. The study is the further development of the general approach proposed in our previous article15 [J. Opt. Soc. Am.A17, 2029 (2001)]. In the present article in addition to the more rigorous derivation of the expression for the mean backscattering signal the expressions for the fluctuation characteristics (correlation functions) are provided. These expressions can be used for the characterization of multiscattering media by the analysis of the results of backscattering experiments.
PAIRING-FLUCTUATION EFFECT IN QUASI-TWO-DIMENSIONAL SUPERCONDUCTIVITY
Authors: YAN XIN-ZHONG
Published: February 2003

We present a self-consistent approach to deal with the pairing-fluctuation effects in quasi-two-dimensional superconducting systems. Besides the Cooper pairs in the Bose–Einstein condensate, there are pairs occupying the excited states, which results in the predominant fluctuations. The low-lying excited states are the collective modes. On the basis of ladder-diagram approximation, we treat the single particles and the pairs on an equal-footing manner. The Green's function of single particles is obtained as an analytic solution to a cubic equation. The bosonic degrees of freedom are relevant to the pseudogap physics in the high-T c cuprates. The superconducting order parameter and the transition temperature are substantially reduced from the values of the mean-field theory. The calculated phase boundary of superconducting state can reasonably describe the experiment data for cuprates.
SUPPORTING AGENT-ORIENTED MODELLING WITH UML
Authors: BERGENTI FEDERICO , POGGI AGOSTINO
Published: February 2003

Software engineering relies on the possibility of describing a system at different levels of abstraction. Agent-oriented software engineering introduces a new level of abstraction, that we called agent level, to allow the architect modelling a system in terms of interacting agents. This level of abstraction is not supported by an accepted set of tools and notations yet, even if a number of proposals are available. This paper introduces: (i) An UML-based notation capable of modelling a system at the agent level and (ii) A development framework, called ParADE, exploiting such a notation. The notation we propose is formalized in terms of a UML profile and it supports the realisation of artefacts modelling two basic concepts of the agent level, i.e., the architecture of the multi-agent system and the ontology followed by agents. The choice of formalising our notation in terms of a UML profile allows using it with any off-the-shelf CASE tool. The ParADE framework takes advantage of this choice by providing a code generator capable of producing skeletons of FIPA-compliant agents from XMI files of agent-oriented models. The developer is requested to complete the generated skeletons exploiting the services that ParADE and the underlying agent platform provide.
A METHODOLOGY FOR MODELING INTERACTIONS IN COOPERATIVE INFORMATION SYSTEMS USING COLOURED PETRI NETS
Authors: RAMOS-QUINTANA FERNANDO , FRAUSTO-SOLIS JUAN , CAMARGO-SANTACRUZ FRANCISCO
Published: February 2003

Cooperative Information Systems (CIS) become relevant to integrate different kinds of systems so as to work collaboratively for a common goal. CIS are considered by nature as dynamic systems, and one of the most difficult problems is how to model and control multiple simultaneous interactions among agents in a friendly way. Consequently, expressiveness becomes a problem related to the representation so far, the similar systems cope neither with the problem of expressiveness nor with multiple interactions in a satisfactory way. It is proposed an integrated methodology based on Coloured Petri Nets (CPN) in order to model the interaction mechanism in a CIS and reduce the associated complexity in the representation of the dynamic of the system. The methodology integrates mainly: (a) the action basic loop in order to represent the system interactions and to model organization conversations, (b) the CPN in the interaction design and system simulation, (c) the communicative acts of FIPA (Foundation for Intelligent Physical Agents), included in the Agent Communication Language Specification.
DEFECT DETECTION FOR EXECUTABLE SPECIFICATIONS — AN EXPERIMENT
Authors: HOUDEK FRANK , SCHWINN THILO , ERNST DIETMAR
Published: February 2003

The deployment of executable specifications has increased significantly in the last few years. Just as with any other specification documents, these specifications must be examined to ensure the necessary degree of quality. A common and successful technique used for examining traditional specifications is inspection. Now the question has arisen whether inspections on executable specification are the best choice, or if other techniques which use the execution capabilities of the models perform better.

In this paper, we empirically compare several defect detection techniques for executable specifications. In particular, we examine inspections, testing, and ad-hoc simulation. Here, we use the specification languages Statemate and Matlab/Simulink. Also, we take a closer look at the inspection process itself and try to quantify the benefits of an inspection meeting for executable specifications.
BAYESIAN-LEARNING BASED GUIDELINES TO DETERMINE EQUIVALENT MUTANTS
Authors: VINCENZI AURI MARCELO RIZZO , NAKAGAWA ELISA YUMI , MALDONADO JOSÉ CARLOS , DELAMARO MÁRCIO EDUARDO , ROMERO ROSELI APARECIDA FRANCELIN
Published: February 2003

Mutation testing (Mutation Analysis), although powerful in revealing faults, is considered a computationally expensive criterion, due to the high number of mutants created and the effort to determine the equivalent mutants. Using mutation-based alternative testing criteria it is possible to reduce the number of mutants but it is still necessary to determine the equivalent ones. In this paper the Bayesian Learning(one of the Artificial Intelligence techniques used in machine learning) is investigated to define the Bayesian Learning-Based Equivalent Detection Technique (BaLBEDeT), which provides guidelines to help the tester to analyze the live mutants in order to determine the equivalent ones.
THE PHYSICAL BASIS FOR PARRONDO'S GAMES
Authors: ALLISON ANDREW , ABBOTT DEREK
Published: February 2003

It has been reported that the original inspiration for Parrondo's games was a physical system called a "flashing Brownian ratchet." The relationship seems to be intuitively plausible but has not previously established with rigor. This is the problem that we address in this paper.

The dynamics of a Brownian particle in a flashing Brownian ratchet are the result of diffusion and of externally applied forces. The probability density, of finding the particle at a certain place and time, can be mathematically modelled using a Partial Differential Equation (PDE) namely the Fokker-Planck Equation. In this paper, we apply standard finite-difference methods of numerical analysis to the Fokker-Planck Equation. We derive a set of finite difference equations and show that they have the same form as Parrondo's games which justifies the claim that Parrondo's games are a discrete-time, discrete-space version of a flashing Brownian ratchet. We claim that Parrondo's games are effectively a particular way of sampling a Fokker-Planck Equation. Our difference equations are a natural and physically motivated generalization of Parrondo's games. We refer to some well established theorems of numerical analysis to suggest conditions under which the solutions to the difference equations and partial differential equations would converge to the same solution.

The diffusion operator, implicitly assumed in Parrondo's original games, reduces to a pre-existing numerical method called "The Schmidt formula." There is actually an infinite continuum of possible diffusion operators and the Schmidt formula is at one extreme of the feasible range. We point out that an operator in the middle of the feasible range, with half-period binomial weightings, would be a better representation of the underlying physics. We present a modified form of Parrondo's games based on the central diffusion operator.

We suggest that the finite difference method presented here will be useful in the simulation and design of real physical flashing Brownian ratchets.
Cations as Hydrogen Bond Donors: A View of Electrostatic Interactions in DNA
Authors: Subirana Juan A. , Soler-López Montserrat
Published: February 2003

▪ Abstract  Cations are bound to nucleic acids in a solvated state. High-resolution X-ray diffraction studies of oligonucleotides provide a detailed view of Mg2+, and occasionally other ions bound to DNA. In a survey of several such structures, certain general observations emerge. First, cations bind preferentially to the guanine base in the major groove or to phosphate group oxygen atoms. Second, cations interact with DNA most frequently via water molecules in their primary solvation shell, direct ion-DNA contacts being only rarely observed. Thus, the solvated ions should be viewed as hydrogen bond donors in addition to point charges. Finally, ion interaction sites are readily exchangeable: The same site may be occupied by any ion, including spermine, as well as by a water molecule.
New Insight into Site-Specific Recombination from Flp Recombinase-DNA Structures
Authors: Chen Yu , Rice Phoebe A.
Published: February 2003

▪ Abstract  The λ integrase, or tyrosine-based family of site-specific recombinases, plays an important role in a variety of biological processes by inserting, excising, and inverting DNA segments. Flp, encoded by the yeast 2-μm plasmid, is the best-characterized eukaryotic member of this family and is responsible for maintaining the copy number of this plasmid. Over the past several years, structural and biochemical studies have shed light on the details of a common catalytic scheme utilized by these enzymes with interesting variations under different biological contexts. The emergence of new Flp structures and solution data provides insights not only into its unique mechanism of active site assembly and activity regulation but also into the specific contributions of certain protein residues to catalysis.