Searching behaviour and diet of Oystercatcher Haematopus ostralegus pairs feeding in their territories

Search path, searching behaviour and diet of pairs of Oystercatchers feeding in mudflat territories were studied during spring. females ate Nereis, Mya, small unidentified prey, probably Corophium, and a few Macoma, whereas males primarily ate Macoma. Even when female and male foraged in the same site, they often caught different prey. The combination of 'The Search-rate/Detection Model' (Gendron & Staddon 1983) and 'The Harvestable Prey Model' (Zwarts & Wanink 1993) provide the theoretical framework in which to explain these differences in diet. Macoma are thought to be more cryptic than Nereis, Mya and Corophium. Therefore females, while searching at a faster rate than their respective mates, caught far fewer cryptic prey, but a greater number of more conspicuous prey than their mates. On the basis of distances moved before and after capturing prey, males exhibited area-restricted searching for Macoma and Corophium. In contrast, females did not exhibit any area-restricted searching. it is suggested that the distribution of Macoma and Corophium available to males searching slowly was more clumped than that of these two prey species available to females searching more quickly.

A comparison of family functioning, temperament, and childhood conditions in monozygotic twin pairs discordant for lifetime bulimia nervosa

Objective: The authors investigated differences between twins in nine pairs of female monozygotic twins in the Australian Twin Registry who were discordant for lifetime bulimia nervosa. Method: The twins affected and unaffected by lifetime bulimia nervosa were compared on self-report measures, including a measure of parental bonding, four measures of temperament, and six early-childhood medical conditions. Results: No twins had current bulimia nervosa, and there was no difference in weight or eating status between the affected and unaffected twins. The affected twins reported significantly lower self-esteem and less warmth but more overprotection by their mothers during childhood. Conclusions: Although limited by the small number of discordant twin pairs and the inability to detect causal relationships, these results suggest that environmental influences that promote low self-esteem may also increase the risk for bulimia nervosa. These temperamental differences may explain the discrepancies in parenting or perceived parenting.

Concordance of iron indices in homozygote and heterozygote sibling pairs in hemochromatosis families: implications for family screening

Background/Aims: Concordance of iron indices between same sex siblings homozygous for the cysteine-to-tyrosine substitution at amino acid 282 (C282Y) mutation suggests that the variable phenotype in hereditary hemochromatosis is caused by genetic factors. Concordance of iron indices between same-sex heterozygous sibling pairs would provide further evidence of genetic modifiers of disease expression, and guidance for family screening strategies of subjects heterozygous for the C282Y mutation. Methods: We compared the iron indices of 35 C282Y homozygous and 35 C282Y heterozygous same-sex sibling pairs. To clarify whether concordance between siblings was due to environmental or genetic factors we compared the iron indices of 164 C282Y homozygous-normal, same-sex dizygotic twins. Results: Serum ferritin (r = 0.50, P = 0.003), hepatic iron concentration (r = 0.61, P = 0.025) and hepatic iron index (r = 0.67, P = 0.01) were highly concordant in C282Y homozygotes. Heterozygote siblings were concordant for serum ferritin (r = 0.76, P = 0.0001) and transferrin saturation (r = 0.79, P = 0.0001). Homozygote-normal same-sex dizygotic twins were concordant for serum ferritin (r = 0.62, P = 0.0001) but not for transferrin saturation. Conclusions: Concordance of iron indices exists in C282Y homozygote and heterozygote sibling pairs. Siblings of expressing C282Y heterozygotes require phenotypic assessment. These data provide evidence for modifying genes influencing disease expression in hemochromatosis. (C) 2002 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.

Transdermal penetration of vasoconstrictors - Present understanding and assessment of the human epidermal flux and retention of free bases and ion-pairs

Purpose. As reductions in dermal clearance increase the residence time of solutes in the skin and underlying tissues we compared the topical penetration of potentially useful vasoconstrictors (VCs) through human epidermis as both free bases and ion-pairs with salicylic acid (SA). Methods. We determined the in vitro epidermal flux of ephedrine, naphazoline, oxymetazoline, phenylephrine, and xylometazoline applied as saturated solutions in propylene glycol: water (1: 1) and of ephedrine, naphazoline and tetrahydrozoline as 10% solutions of 1: 1 molar ratio ion-pairs with SA in liquid paraffin. Results. As free bases, ephedrine had the highest maximal flux, Jmax = 77.4 +/- 11.7 mug/cm(2)/h, being 4-fold higher than tetrahydrozoline and xylometazoline, 6-fold higher than phenylephrine, 10-fold higher than naphazoline and 100-fold higher than oxymetazoline. Stepwise regression of solute physicochemical properties identified melting point as the most significant predictor of flux. As ion-pairs with SA, ephedrine and naphazoline had similar fluxes (11.5 +/- 2.3 and 12.0 +/- 1.6 mug/cm(2)/h respectively), whereas tetrahydrozoline was approximately 3-fold slower. Corresponding fluxes of SA from the ion-pairs were 18.6 +/- 0.6, 7.8 +/- 0.8 and 1.1 +/- 0.1 respectively. Transdermal transport of VC's is discussed. Conclusions. Epidermal retention of VCs and SA did not correspond to their molar ratio on application and confirmed that following partitioning into the stratum corneum, ion-pairs separate and further penetration is governed by individual solute characteristics.

Using identity-by-de scent information in affected sib pairs to increase the efficiency of genetic association studies

T he aim of this study was to determine whether identity-by-descent (IBD) information for affected sib pairs (ASPs) can be used to select a sample of cases for a genetic case-control study which will provide more power for detecting association with loci in a known linkage region. By modeling the expected frequency of the disease allele in ASPs showing IBD sharing of 0, 1, or 2 alleles, and considering additive, recessive, and dominant disease models, we show that cases selected from IBD 2 families are best for this purpose, followed by those selected from IBD 1 families; least useful are cases selected from IBD 0 families.

Comment on "Grover search with pairs of trapped ions"

In this Comment on Feng's paper [Phys. Rev. A 63, 052308 (2001)], we show that Grover's algorithm may be performed exactly using the gate set given, provided that small changes are made to the gate sequence. An analytic expression for the probability of success of Grover's algorithm for any unitary operator U instead of Hadamard gate is presented.

Existence of complementary pairs of proportionally balanced designs

Proportionally balanced designs (pi BDs) were introduced by Gray and Matters in response to a need for the allocation of markers of the Queensland Core Skills Test to have a certain property. Subsequent papers extended the theoretical results relating to such designs and provided further instances and general constructions. This work focused on designs comprising blocks of precisely two sizes, and when each variety occurs with one of precisely two possible frequencies. Two designs based on the set V of varieties are complementary if, whenever B is a block of one, then its complement with regard to the set V is a block of the other. Here we present necessary conditions for the existence of complementary pairs of such pi BDs and provide lists of some restricted parameter sets satisfying these necessary conditions. The lists are arranged according to the number of blocks. We demonstrate that not all of these parameter sets give rise to designs. However we establish by construction of the sets of blocks that, for every feasible number of blocks less than or equal to 100, with the possible exception of 63, there exists at least one pair of complementary pi BDs. We also investigate the conditions under which the complementary design can be isomorphic to the original design, and again provide a list of feasible parameters for pairs of such designs with at most 400 blocks.

Replicated linkage for eye color on 15q using comparative ratings of sibling pairs

The aim of the study was to perform a genetic linkage analysis for eye color, for comparative data. Similarity in eye color of mono- and dizygotic twins was rated by the twins' mother, their father and/or the twins themselves. For 4748 twin pairs the similarity in eye color was available on a three point scale (not at all alike-somewhat alike-completely alike), absolute eye color on individuals was not assessed. The probability that twins were alike for eye color was calculated as a weighted average of the different responses of all respondents on several different time points. The mean probability of being alike for eye color was 0.98 for MZ twins (2167 pairs), whereas the mean probability for DZ twins was 0.46 (2537 pairs), suggesting very high heritability for eye color. For 294 DZ twin pairs genome-wide marker data were available. The probability of being alike for eye color was regressed on the average amount of IBD sharing. We found a peak LOD-score of 2.9 at chromosome 15q, overlapping with the region recently implicated for absolute ratings of eye color in Australian twins [Zhu, G., Evans, D. M., Duffy, D. L., Montgomery, G. W., Medland, S. E., Gillespie, N. A., Ewen, K. R., Jewell, M., Liew, Y. W., Hayward, N. K., Sturm, R. A., Trent, J. M., and Martin, N. G. (2004). Twin Res. 7:197-210] and containing the OCA2 gene, which is the major candidate gene for eye color [Sturm, R. A. Teasdale, R. D, and Box, N. F. (2001). Gene 277:49-62]. Our results demonstrate that comparative measures on relatives can be used in genetic linkage analysis.

Sex Differences in Symptoms of Depression in Unrelated Individuals and Opposite-Sex Twin and Sibling Pairs

Diagnosis of a major depressive episode by the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association requires 5 out of 9 symptoms to be present. Therefore, individuals may differ in the specific symptoms they experience and reach a diagnosis of depression via different pathways. It has been suggested that depressed women more often report symptoms of sleep disturbance, appetite or weight disturbance, fatigue, feelings of guilt/worthlessness and psychomotor retardation than depressed men. In the current study, we investigate whether depressed men and women differ in the symptoms they report. Two samples were selected from a sample of Dutch and Australian twins and siblings. First, Dutch and Australian unrelated depressed individuals were selected. Second, a matched epidemiological sample was created consisting of opposite-sex twin and sibling pairs in which both members were depressed. No sex differences in prevalence rates for symptoms were found, with the exception of decreased weight in women in the sample of unrelated individuals. In general, the similarities in symptoms seem to far outweigh the differences in symptoms between men and women. This signifies that men and women are alike in their symptom profiles for major depression and genes for depression are probably expressed in the same way in the two sexes.

Genetic Influences on Exercise Participation in 37.051 Twin Pairs from Seven Countries

Background A sedentary lifestyle remains a major threat to health in contemporary societies. To get more insight in the relative contribution of genetic and environmental influences on individual differences in exercise participation, twin samples from seven countries participating in the GenomEUtwin project were used. Methodology Self-reported data on leisure time exercise behavior from Australia, Denmark, Finland, Norway, the Netherlands, Sweden and United Kingdom were used to create a comparable index of exercise participation in each country (60 minutes weekly at a minimum intensity of four metabolic equivalents). Principal Findings Modest geographical variation in exercise participation was revealed in 85,198 subjects, aged 19–40 years. Modeling of monozygotic and dizygotic twin resemblance showed that genetic effects play an important role in explaining individual differences in exercise participation in each country. Shared environmental effects played no role except for Norwegian males. Heritability of exercise participation in males and females was similar and ranged from 48% to 71% (excluding Norwegian males). Conclusions Genetic variation is important in individual exercise behavior and may involve genes influencing the acute mood effects of exercise, high exercise ability, high weight loss ability, and personality. This collaborative study suggests that attempts to find genes influencing exercise participation can pool exercise data across multiple countries and different instruments

A Bethe ansatz solvable model for superpositions of Cooper pairs and condensed molecular bosons

We introduce a general Hamiltonian describing coherent superpositions of Cooper pairs and condensed molecular bosons. For particular choices of the coupling parameters, the model is integrable. One integrable manifold, as well as the Bethe ansatz solution, was found by Dukelsky et al. [J. Dukelsky, G.G. Dussel, C. Esebbag, S. Pittel, Phys. Rev. Lett. 93 (2004) 050403]. Here we show that there is a second integrable manifold, established using the boundary quantum inverse scattering method. In this manner we obtain the exact solution by means of the algebraic Bethe ansatz. In the case where the Cooper pair energies are degenerate we examine the relationship between the spectrum of these integrable Hamiltonians and the quasi-exactly solvable spectrum of particular Schrodinger operators. For the solution we derive here the potential of the Schrodinger operator is given in terms of hyperbolic functions. For the solution derived by Dukelsky et al., loc. cit. the potential is sextic and the wavefunctions obey PT-symmetric boundary conditions. This latter case provides a novel example of an integrable Hermitian Hamiltonian acting on a Fock space whose states map into a Hilbert space of PE-symmetric wavefunctions defined on a contour in the complex plane. (c) 2006 Elsevier B.V. All rights reserved.

Birth weight and age at menopause in Australian female twin pairs: exploration of the fetal origin hypothesis

In a twin sample where duration of gestation can be controlled, a specific example of the fetal origins hypothesis concerning association between low birth weight and early age at menopause is explored. The hypothesis is based on the physiologically plausible path from intrauterine growth retardation and reduced numbers of primary follicles to an earlier menopause. The sample comprised 323 Australian female twin pairs where both co-twins had reached menopause naturally and reported on their weight at birth. Regression analysis showed no linear association between the two variables (P = 0.371, r(2) = 0.0009). Intra-pair differences in age at menopause were investigated in the context of relative birth weight of co-twins. In 265 pairs an intra-pair birth a eight difference was reported. In monozygotic (MZ) pairs (n = 168) this allowed for control of genetic effects as well as gestation duration. No significant differences dependent on birth weight relative to co-twin were found for age at natural menopause in either MZ or dizygotic (DZ) twin pairs, even in pairs whose birth weights differed markedly. There was some indication that twins with premature ovarian failure were heavier at birth than twins with normal or later menopausal age. We conclude that the hypothesis that lower birth weight is associated with earlier menopause is not supported by our data.

Comparison of surveys used to measure physical activity

Objective: To compare the level of agreement in results obtained from four physical activity (PA) measurement instruments that are in use in Australia and around the world. Methods: 1,280 randomly selected participants answered two sets of PA questions by telephone. 428 answered the Active Australia (AA) and National Health Surveys, 427 answered the AA and CDC Behavioural Risk Factor Surveillance System surveys (BRFSS), and 425 answered the AA survey and the short International Physical Activity Questionnaire (IPAQ). Results: Among the three pairs of survey items, the difference in mean total PA time was lowest when the AA and NHS items were asked (difference=24) (SE:17) minutes, compared with 144 (SE:21) mins for AA/BRFSS and 406 (SE:27) mins for AA/IPAQ). Correspondingly, prevalence estimates for 'sufficiently active' were similar for AA and NHS (56% and 55% respectively), but about 10% higher when BRFSS data were used, and about 26% higher when the IPAQ items were used, compared with estimates from the AA survey. Conclusions: The findings clearly demonstrate that there are large differences in reported PA times and hence in prevalence estimates of 'sufficient activity' from these four measures. Implications: It is important to consistently use the same survey for population monitoring purposes. As the AA survey has now been used three times in national surveys, its continued use for population surveys is recommended so that trend data ever a longer period of time can be established.