bluuebunny/crossref_metadata_2025_split huggingface dataset:
Consequences of inbreeding depression due to sex-linked loci for the maintenance of males and outcrossing in branchiopod crustaceans
Authors: PANNELL JOHN R. 
Published: May 2008

SummaryAndrodioecy, where males co-occur with hermaphrodites, is a rare sexual system in plants and animals. It has a scattered phylogenetic distribution, but it is common and has persisted for long periods of evolutionary time in branchiopod crustaceans. An earlier model of the maintenance of males with hermaphrodites in this group, by Ottoet al.(1993), considered the importance of male–hermaphrodite encounter rates, sperm limitation, male versus hermaphrodite viability and inbreeding depression suffered by selfed progeny. Here I advance this model in two ways: (1) by exploring the conditions that would allow the invasion of hermaphrodites into a dioecious population and that of females into an androdioecious population; and (2) by incorporating a term that accounts for the potential effects of genetic load linked to a dominant hermaphrodite-determining allele in androdioecious populations. The new model makes plausible sense of observations made in populations of the speciesEulimnadia texana, one of a number of related species whose common ancestor evolved hermaphroditism (and androdioecy) from dioecy. In particular, it offers an explanation for the long evolutionary persistence of androdioecy in branchiopods and suggests reasons for why dioecy has not re-evolved in the clade. Finally, it provides a rather unusual illustration of the implications of the degeneration of loci linked to a sex-determining locus.
The use of an AMMI model and its parameters to analyse yield stability in multi-environment trials
Authors: SABAGHNIA N. , SABAGHPOUR S. H. , DEHGHANI H. 
Published: May 2008

SUMMARYGenotype by environment (G×E) interaction effects are of special interest for breeding programmes to identify adaptation targets and test locations. Their assessment by additive main effect and multiplicative interaction (AMMI) model analysis is currently defined for this situation. A combined analysis of two former parametric measures and seven AMMI stability statistics was undertaken to assess G×E interactions and stability analysis to identify stable genotypes of 11 lentil genotypes across 20 environments. G×E interaction introduces inconsistency in the relative rating of genotypes across environments and plays a key role in formulating strategies for crop improvement. The combined analysis of variance for environments (E), genotypes (G) and G×E interaction was highly significant (P<0·01), suggesting differential responses of the genotypes and the need for stability analysis. The parametric stability measures of environmental variance showed that genotype ILL 6037 was the most stable genotype, whereas the priority index measure indicated genotype FLIP 82-1L to be the most stable genotype. The first seven principal component (PC) axes (PC1–PC7) were significant (P<0·01), but the first two PC axes cumulatively accounted for 71% of the total G×E interaction. In contrast, the AMMI stability statistics suggested different genotypes to be the most stable. Most of the AMMI stability statistics showed biological stability, but the SIPCF statistics of AMMI model had agronomical concept stability. The AMMI stability value (ASV) identified genotype FLIP 92-12L as a more stable genotype, which also had high mean performance. Such an outcome could be regularly employed in the future to delineate predictive, more rigorous recommendation strategies as well as to help define stability concepts for recommendations for lentil and other crops in the Middle East and other areas of the world.
Effects of phosphates and citrates on sediment formation in UHT goats' milk
Authors: Boumpa Theodora , Tsioulpas Alexandros , Grandison Alistair S , Lewis Mike J 
Published: May 2008

Sediment formation was investigated during UHT treatment of goats' milk, subjected to indirect treatment at 140°C for 2 s, with upstream homogenisation. Stabilisers evaluated were sodium hexametaphosphate (SHMP), trisodium citrate (TSC), disodium hydrogen orthophosphate (DSHP), and sodium dihydrogen orthophosphate (SDHP). With no added stabiliser, goats' milk produced a heavy sediment on UHT treatment. Addition of SDHP reduced pH, had little effect on ionic calcium and did not substantially reduce sediment. However, addition of SHMP, DSHP and TSC each reduced ionic calcium, increased ethanol stability and reduced sediment. Following stabiliser additions, there was a good correlation between ethanol stability and ionic calcium (R2=0·85) but not between ethanol stability and pH (R2=0·08). Overall, reducing ionic calcium reduced the amount of sediment formed for all these three stabilisers, although there was no single trend line between sediment formation and ionic calcium concentration. Sediment formation was not well correlated with pH for TSC or for SHMP, but it was for DSHP, making it the only stabiliser where sediment formation correlated well both with ionic calcium and pH, which might account for its effectiveness at higher ionic calcium levels. Sediment was much reduced when the temperature was reduced from 140°C to 125°C and 114°C. There were no further changes in sediment on storage for two weeks. Analysis of the sediment showed that it was predominantly fat and protein, with a mass ratio ranging between 1·43:1 and 1·67:1. Its mineral content was usually less than 5% of dry weight. The maximum amounts of P and Ca were found to be 2·32% and 1·63%, respectively.
The prevalence ofCryptosporidiumspecies and subtypes in human faecal samples in Ireland
Authors: ZINTL A. , PROCTOR A. F. , READ C. , DEWAAL T. , SHANAGHY N. , FANNING S. , MULCAHY G. 
Published: May 2008

SUMMARYCryptosporidiumis an important cause of diarrhoeal disease worldwide and, as several recent waterborne outbreaks have shown, poses a significant threat to public health in Ireland. We identified theCryptosporidiumspp. in 199 positive human stool samples by PCR–RFLP of the 18S rRNA and COWP gene loci. Subspecies were identified in 104 samples by sequence analysis of the 60 kDa glycoprotein (gp60) gene fragment. OverallC. parvumwas identified in 80%, andC. hominisin 20% of cases. No otherCryptosporidiumspp. were detected.C. parvumwas by far the most common species in the rural, more sparsely populated west of Ireland and exhibited a pronounced spring peak coincident with a peak in the national cryptosporidiosis incidence rate. Our data indicated a trend towards higher proportions ofC. hominisin older age groups. Ninety-nine per cent of all subtypedC. parvumisolates belonged to allele family IIa, of which allele IIaA18G3R1 was by far the most common (63%). According to a recent study by Thompson and colleagues [Parasitology Research(2007),100, 619–624] this allele is also the most common in Irish cattle. Subtyping of theC. hominisisolates indicated that they belonged to a geographically widely distributed allele (IbA10G2) known to have caused several water- and foodborne outbreaks around the world. The predominance ofC. parvum, its geographic and seasonal distribution and the IIaA18G3R1 subtype underlines the importance of zoonoticCryptosporidiumtransmission in Ireland.
Preparing the exoplanet search with PRIMA: searching for reference stars and target characterization
Authors: Geisler R. , Setiawan J. , Henning Th. , Queloz D. , Quirrenbach A. , Launhardt R. , Müller A. , Reffert S. , Weise P. ,   ESPRI consortium
Published: May 2008

AbstractThe PRIMA (Phase-Referenced Imaging and Micro-arcsecond Astrometry) facility at ESO VLTI (Paranal observatory) is expected to be commissioned in mid 2008. The ESPRI (Exoplanet Search with PRIMA) consortium is currently preparing an astrometric survey to search for extrasolar planets. To achieve the scientific goal of this survey, a careful selection of target and reference stars is necessary. Apart from catalog search and modelling, extensive and dedicated preparatory observations are indispensable. Here we present two aspects of the preparatory observation programs: A high dynamic range near infrared (NIR) imaging survey to search for astrometric reference stars around the preselected target stars and characterization of the target stars by using high-resolution spectroscopy.
Reconstruction of the transit signal in the presence of stellar variability
Authors: Alapini Aude , Aigrain Suzanne 
Published: May 2008

AbstractIntrinsic stellar variability can hinder the detection of shallow transits, particularly in space-based data. Therefore, this variability has to be filtered out before running the transit search. Unfortunately, filtering out the low frequency signal of the stellar variability also modifies the transit shape. This results in errors in the measured transit depth and duration used to derive the planet radius, and orbital inclination. We present an evaluation of the magnitude of this effect based on 20 simulated light curves from the CoRoT blind exercise 2 (BT2). We then present an iterative filter which uses the strictly periodic nature of the transits to separate them from other forms of variability, so as to recover the original transit shape before deriving the planet parameters. On average with this filter, we improve the estimation of the transit depth and duration by 15% and 10% respectively.
The On/Off nature of star-planet interactions in the HD 179949 and υ And systems
Authors: Shkolnik Evgenya , Bohlender David A. , Walker Gordon A. H. , Cameron Andrew Collier 
Published: May 2008

AbstractEvidence suggesting an observable magnetic interaction between a star and its hot Jupiter (Porb< 7 days,a< 0.1 AU,Mpsini> 0.2MJ) appears as a cyclic variation of stellar activity synchronized to the planet's orbit. HD 179949 has been observed almost every year since 2001. Synchronicity of the Ca II H & K emission with the orbit is clearly seen in four out of six epochs, while rotational modulation withProt=7 days is apparent in the other two seasons. We observe a similar phenomenon on υ And, which displays rotational modulation (Prot=12 days) in September 2005, while in 2002 and 2003 variations appear to correlate with the planet's orbital period. This on/off nature of star-planet interaction (SPI) in the two systems is likely a function of the changing stellar magnetic field structure throughout its activity cycle. The tentative correlation between this activity in the 13 stars we have observed to date and the ratio ofMpsinito the planet's rotation period, a quantity proportional to the hot Jupiter's magnetic moment, first presented in Shkolniket al. (2005) remains viable. This work furthers the characterization of SPI, improving its potential as a probe of extrasolar planetary magnetic fields.
Tidal friction in close-in planets
Authors: Rodríguez Adrián , Ferraz-Mello Sylvio , Hussmann Hauke 
Published: May 2008

AbstractWe use Darwin's theory (Darwin, 1880) to derive the main results on the orbital and rotational evolution of a close-in companion (exoplanet or planetary satellite) due to tidal friction. The given results do not depend on any assumption linking the tidal lags to the frequencies of the corresponding tide harmonics (except that equal frequency harmonics are assumed to span equal lags). Emphasis is given to the study of the synchronization of the planetary rotation in the two possible final states for a non-zero eccentricity : (1) the super-synchronous stationary rotation resulting from the vanishing of the average tidal torque; (2) the capture into a 1:1 spin-orbit resonance (true synchronization), which is only possible if an additional torque exists acting in opposition to the tidal torque. Results are given under the assumption that this additional torque is produced by a non-tidal permanent equatorial asymmetry of the planet. The indirect tidal effects and some non-tidal effects due to that asymmetry are considered. For sake of comparison with other works, the results obtained when tidal lags are assumed proportional to the corresponding tidal wave frequencies are also given.
Testing planet formation theories with giant stars
Authors: Pasquini Luca , Döllinger M.P. , Hatzes A. , Setiawan J. , Girardi L. , da Silva L. , de Medeiros J. R. , Weiss A. 
Published: May 2008

AbstractPlanet searches around evolved giant stars are bringing new insights to planet formation theories by virtue of the broader stellar mass range of the host stars compared to the solar-type stars that have been the subject of most current planet searches programs. These searches among giant stars are producing extremely interesting results. Contrary to main sequence stars planet-hosting giants do not show a tendency of being more metal rich. Even if limited, the statistics also suggest a higher frequency of giant planets (at least 10%) that are more massive compared to solar-type main sequence stars.The interpretation of these results is not straightforward. We propose that the lack of a metallicity-planet connection among giant stars is due to pollution of the star while on the main sequence, followed by dillution during the giant phase. We also suggest that the higher mass and frequency of the planets are due to the higher stellar mass. Even if these results do not favor a specific formation scenario, they suggest that planetary formation might be more complex than what has been proposed so far, perhaps with two mechanisms at work and one or the other dominating according to the stellar mass. We finally stress as the detailed study of the host stars and of the parent sample is essential to derive firm conclusions.
Migration and Final Location of Hot Super Earths in the Presence of Gas Giants
Authors: Zhou Ji-Lin , Lin Douglas N. C. 
Published: May 2008

AbstractBased on the conventional sequential-accretion paradigm, we have proposed that, during the migration of first-born gas giants outside the orbits of planetary embryos, super Earth planets will form inside the 2:1 resonance location by sweeping of mean motion resonances (Zhou et al. 2005). In this paper, we study the subsequent evolution of a super Earth (m1) under the effects of tidal dissipation and perturbation from a first-born gas giant (m2) in an outside orbit. Secular perturbation and mean motion resonances (especially 2 : 1 and 5 : 2 resonances) between m1 and m2 excite the eccentricity of m1, which causes the migration of m1 and results in a hot super Earth. The calculated final location of the hot super Earth is independent of the tidal energy dissipation factor Q′. The study of migration history of a Hot Super Earth is useful to reveal it's Q′ value and to predict its final location in the presence of one or more hot gas giants. When this investigation is applied to the GJ876 system, it correctly reproduces the observed location of GJ876d around 0.02 AU.
Disc signatures in a new population of low mass YSOs in ρ Ophiuchi
Authors: de Oliveira Catarina Alves , Casali Mark 
Published: May 2008

AbstractThe deepest near-IR variability survey of the ρ Ophiuchi cluster with the WFCAM/UKIRT has been used to uncover a new population of young low mass objects. Evidence for the existence of discs around the new objects has been found when combining data with IRAC/Spitzer observations. A new insight on the frequency and dynamics of discs around low mass YSOs is given, essential for understanding the origin and evolution of circumstellar discs and ultimately the environment for planet formation.
3D SPH simulations of grain growth in protoplanetary disks
Authors: Laibe Guillaume , Gonzalez Jean-François , Fouchet Laure , Maddison Sarah T. 
Published: May 2008

AbstractWe present the first results of the treatment of grain growth in our 3D, two-fluid (gas+dust) SPH code describing protoplanetary disks. We implement a scheme able to reproduce the variation of grain sizes caused by a variety of physical processes and test it with the analytical expression of grain growth given by Stepinski & Valageas (1997) in simulations of a typical T Tauri disk around a one solar mass star. The results are in agreement with a turbulent growing process and validate the method. We are now able to simulate the grain growth process in a protoplanetary disk given by a more realistic physical description, currently under development. We discuss the implications of the combined effect of grain growth and dust vertical settling and radial migration on subsequent planetesimal formation.
Runaway migration in a multiple-protoplanet system
Authors: Zhang Hui , Zhou Ji-Lin 
Published: May 2008

AbstractWe investigate the migration of two giant planets embedded in a proto-stellar disk. The inner planet(initially located at R10=1) is of 1 Jupiter mass and the outer one(R20=1.5) is of 1 Saturn mass. We find that due to the existence of the inner massive planet, the outer planet can not open a clear gap. Instead of an inward migration and being captured by the mean motion resonance of the inner planet, the outer planet undergoes an outward runaway migration. We conclude that this runaway migration is caused by the co-rotation torque in the co-orbital region of the outer planet and sustained by the wave(flow) driven by the inner massive planet.
Formation and transformation of the 3:1 mean-motion resonance in 55 Cancri System
Authors: Zhou Li-Yong , Ferraz-Mello Sylvio , Sun Yi-Sui 
Published: May 2008

AbstractWe report in this paper the numerical simulations of the capture into the 3:1 mean-motion resonance between the planets b and c in the 55 Cancri system. The results show that this resonance can be obtained by a differential planetary migration. The moderate initial eccentricities, relatively slower migration and suitable eccentricity damping rate increase significantly the probability of being trapped in this resonance. Otherwise, the system crosses the 3:1 commensurability avoiding resonance capture, to be eventually captured into a 2:1 resonance or some other higher-order resonances. After capture into resonance, the system can jump from one orbital configuration to another one if the migration continues, making a large region of the configuration space accessible for a resonance system. These investigations help us understand the diversity of resonance configurations and put some constraints on the early dynamical evolution of orbits in the extra-solar planetary systems.
Orbital stability of planets in binary systems: A new look at old results
Authors: Eberle J. , Cuntz M. , Musielak Z. E. 
Published: May 2008

AbstractAbout half of all known stellar systems with Sun-like stars consist of two or more stars, significantly affecting the orbital stability of any planet in these systems. This observational evidence has prompted a large array of theoretical research, including the derivation of mathematically stringent criteria for the orbital stability of planets in stellar binary systems, valid for the “coplanar circular restricted three-body problem”. In the following, we use these criteria to explore the validity of results from previous theoretical studies.
Small Birth Weight and Later Body Composition and Fat Distribution in Adolescents: The AVENA Study
Authors: Labayen Idoia , Moreno Luis A. , Ruiz Jonatan R. , González‐Gross Marcela , Wärnberg Julia , Breidenassel Christina , Ortega Francisco B. , Marcos Ascensión , Bueno Manuel ,   The AVENA Study Group
Published: May 2008

Objective: To assess the association between birth weight and body composition and fat distribution in adolescents, and to test the possible sex‐specific effect in these relationships.Methods and Procedures: A total of 1,223 adolescents 13–18.5 years old (553 male adolescents and 670 female adolescents) born at >35 weeks, were selected from a cross‐sectional multicenter study conducted in five Spanish cities in 2000–2002. BMI was calculated from weight and height. Triceps and subscapular skinfold thickness (ST) were measured on the left side, and fat mass (FM) and fat‐free mass (FFM) were estimated according to the equations of Slaughter et al. Subscapular skinfold adjusted by tricipital (ST) and waist circumference were used as markers of central adiposity.Results: Birth weight Z‐score was positively associated with FFM in female adolescents (P < 0.001), but not in male adolescents, after controlling for age, pubertal stage, gestational age, socioeconomic status, physical activity, and current height (P < 0.001 for interaction between adjusted birth weight Z‐score and sex). Adjusted birth weight Z‐score was inversely associated with central adiposity in male and female adolescents as measured by ST (P = 0.026).Discussion: These results provide further evidence that gender has an important influence on the programming effect of birth weight on later FFM in adolescents because the effect was only observed in female adolescents. Our results suggest that small size for gestational age at birth could program more central subcutaneous fat deposition in adolescents of both sexes, but further research is needed on this issue.
Alcalase®‐catalysed synthesis of the precursor tetrapeptide N‐benzoylarginylglycylaspartylserinamide (Bz‐RGDS‐NH2) of the cell‐adhesion peptide arginylglycylaspartylserine (RGDS)
Authors: Huang Yi‐Bing , Yang Sen , Cai Yu , Wang Hua , Gao Gui , Wu Xiao‐Xia , Xu Li , Zhang Xue‐Zhong 
Published: May 2008

In the present study, a precursor tetrapeptide Bz‐RGDS‐NH2 (N‐benzoylarginylglycylaspartylserinamide) of cell‐adhesion peptide RGDS (arginylglycylaspartylserine) was synthesized by a novel route. First of all, the precursor tripeptide GDS‐NH2 (glycylaspartylserinamide) was synthesized by a chemical method only using aspartic acid and serine at gram scale in four steps. The linkage of the fourth amino acid Bz‐Arg‐OEt (N‐benzoyl‐
L‐arginine ethyl ester) to GDS‐NH2 was completed by an enzymatic method under kinetic control in water‐miscible organic media. An industrial alkaline protease, Alcalase®, with a wide substrate specificity, was used as the catalyst. The effects of organic solvents, pH value, reaction temperature, water content and molar ratio of substrates on the yield of Bz‐RGDS‐NH2 synthesis were examined. The optimum reaction conditions were found to be pH 10.0, 35 °C, 8 h, in an acetonitrile/(Na2CO3/NaHCO3) buffer system (93:7, v/v) with a maximal yield of 65.2%. We found that secondary hydrolysis of the peptide product did not take place in these water‐miscible organic solvents.