711 research outputs found
Relatedness of baculovirus and gypsy retrotransposon envelope proteins
BACKGROUND: Current evidence suggests that lepidopteran baculoviruses may be divided into two phylogenetic groups based on their envelope fusion proteins. One group utilizes gp64, a low pH-dependent envelope fusion protein, whereas the other employs a protein family (e.g. LD130 in the Lymantria dispar nucleopolyhedrovirus) unrelated to gp64, but that is also low pH-dependent. Database searches with members of the LD130 protein family often record significant levels of homology to envelope proteins from a number of insect retrovirus-like transposable elements of the gypsy class. In this report, the significance of the homology between these two types of envelope proteins is analyzed. RESULTS: The significance of the alignment scores was evaluated using Z-scores that were calculated by comparing the observed alignment score to the distribution of scores obtained for alignments after one of the sequences was subjected to 100 random shuffles of its sequence. These analyses resulted in Z-scores of >9 for members of the LD130 family when compared to most gypsy envelope proteins. Furthermore, in addition to significant levels of sequence homology and the presence of predicted signal sequences and transmembrane domains, members of this family contain a possible a furin cleavage motif, a conserved motif downstream of this site, predicted coiled-coil domains, and a pattern of conserved cysteine residues. CONCLUSIONS: These analyses provide a link between envelope proteins from a group of insect retrovirus-like elements and a baculovirus protein family that includes low-pH-dependent envelope fusion proteins. The ability of gypsy retroelements to transpose from insect into baculovirus genomes suggests a pathway for the exchange of this protein between these viral families
Structure of hard-hypersphere fluids in odd dimensions
The structural properties of single component fluids of hard hyperspheres in
odd space dimensionalities are studied with an analytical approximation
method that generalizes the Rational Function Approximation earlier introduced
in the study of hard-sphere fluids [S. B. Yuste and A. Santos, Phys. Rev. A
{\bf 43}, 5418 (1991)]. The theory makes use of the exact form of the radial
distribution function to first order in density and extends it to finite
density by assuming a rational form for a function defined in Laplace space,
the coefficients being determined by simple physical requirements. Fourier
transform in terms of reverse Bessel polynomials constitute the mathematical
framework of this approximation, from which an analytical expression for the
static structure factor is obtained. In its most elementary form, the method
recovers the solution of the Percus-Yevick closure to the Ornstein-Zernike
equation for hyperspheres at odd dimension. The present formalism allows one to
go beyond by yielding solutions with thermodynamic consistency between the
virial and compressibility routes to any desired equation of state. Excellent
agreement with available computer simulation data at and is
obtained. As a byproduct of this study, an exact and explicit polynomial
expression for the intersection volume of two identical hyperspheres in
arbitrary odd dimensions is given.Comment: 18 pages, 7 figures; v2: new references added plus minor changes; to
be published in PR
Virial series for fluids of hard hyperspheres in odd dimensions
A recently derived method [R. D. Rohrmann and A. Santos, Phys. Rev. E. {\bf
76}, 051202 (2007)] to obtain the exact solution of the Percus-Yevick equation
for a fluid of hard spheres in (odd) dimensions is used to investigate the
convergence properties of the resulting virial series. This is done both for
the virial and compressibility routes, in which the virial coefficients
are expressed in terms of the solution of a set of coupled algebraic
equations which become nonlinear for . Results have been derived up
to . A confirmation of the alternating character of the series for , due to the existence of a branch point on the negative real axis, is found
and the radius of convergence is explicitly determined for each dimension. The
resulting scaled density per dimension , where is the
packing fraction, is wholly consistent with the limiting value of 1 for . Finally, the values for predicted by the virial and
compressibility routes in the Percus-Yevick approximation are compared with the
known exact values [N. Clisby and B. M. McCoy, J. Stat. Phys. {\bf 122}, 15
(2006)]Comment: 9 pages, 6 figure
Thermo-statistical description of gas mixtures from space partitions
The new mathematical framework based on the free energy of pure classical
fluids presented in [R. D. Rohrmann, Physica A 347, 221 (2005)] is extended to
multi-component systems to determine thermodynamic and structural properties of
chemically complex fluids. Presently, the theory focuses on -dimensional
mixtures in the low-density limit (packing factor ). The formalism
combines the free-energy minimization technique with space partitions that
assign an available volume to each particle. is related to the
closeness of the nearest neighbor and provides an useful tool to evaluate the
perturbations experimented by particles in a fluid. The theory shows a close
relationship between statistical geometry and statistical mechanics. New,
unconventional thermodynamic variables and mathematical identities are derived
as a result of the space division. Thermodynamic potentials ,
conjugate variable of the populations of particles class with the
nearest neighbors of class are defined and their relationships with the
usual chemical potentials are established. Systems of hard spheres are
treated as illustrative examples and their thermodynamics functions are derived
analytically. The low-density expressions obtained agree nicely with those of
scaled-particle theory and Percus-Yevick approximation. Several pair
distribution functions are introduced and evaluated. Analytical expressions are
also presented for hard spheres with attractive forces due to K\^ac-tails and
square-well potentials. Finally, we derive general chemical equilibrium
conditions.Comment: 14 pages, 8 figures. Accepted for publication in Physical Review
Associations between anxiety disorders and diet quality in a Swiss cohort study.
Anxiety disorders are common in the general population and can have a major impact on a person's behavior. These disorders may also affect shopping and cooking habits, which may lead to a less healthy diet. Thus, we aimed to assess whether any current anxiety disorder or current specific anxiety disorders were associated with diet quality.
Data of 6392 observations of 3993 participants were retrieved from 2 data waves of a population-based prospective cohort study conducted in an urban area in Switzerland. To assess the associations of anxiety status with diet quality measured by the Alternate Healthy Eating Index (AHEI), we performed cross-sectional multilevel random-effects linear regression analyses, which accounted for potential repeated participation and a series of potential confounders.
We observed an association between the presence of any current anxiety disorder and lower diet quality. For the most conclusive model, the AHEI was 1.2 points lower among those with current anxiety disorders compared to those participants with no anxiety disorder (p = 0.016). When specific anxiety disorders were included separately into the model, panic disorder was associated with lower diet quality in the fully adjusted model (p = 0.037).
Our findings of reduced diet quality in people with any current anxiety disorder suggest that practical support is needed when it comes to buying and processing food. This might be systematically addressed in psychotherapy and external interdisciplinary support (e.g. occupational therapy and dietary counselling) should be involved. However, further data is needed to strengthen the findings of the present study
Adherence to dietary recommendations is not associated with depression in two Swiss population-based samples.
Little is known about adherence to dietary recommendations and depression. Furthermore, dietary habits may differ among depression subtypes, which has not been evaluated previously. Two population-based Swiss studies, including 3620 individuals from PsyCoLaus and 11,032 individuals from the Swiss Health Survey 2012 (SHS), were used to examine the associations between adherence to common dietary guidelines and odds of depressive disorders. In both studies, depression was assessed by validated instruments. Adherence to dietary recommendations were assessed by a semi-quantitative food frequency questionnaire (PsyCoLaus) and by single item questions (SHS). Logistic regression analyses were used to assess the association of adhering to dietary recommendations with depression. For the analyses of diet with depression subtypes maximum-likelihood multinomial (polytomous) logistic regression analyses were conducted. No association of adherence to dietary recommendations with current major depressive disorder (MDD) was observed in any of the two study populations except for adherence to fish consumption, which was positively associated with MDD in the SHS. For depression subtypes, statistically significantly positive associations of vegetable consumption and adherence to the 5-a-day recommendation with current unspecified and current melancholic MDD were found. In conclusion, we don't see consistent associations between adherence to dietary recommendations and MDD or subtypes of depression
Conditional pair distributions in many-body systems: Exact results for Poisson ensembles
We introduce a conditional pair distribution function (CPDF) which
characterizes the probability density of finding an object (e.g., a particle in
a fluid) to certain distance of other, with each of these two having a nearest
neighbor to a fixed but otherwise arbitrary distance. This function describes
special four-body configurations, but also contains contributions due to the
so-called mutual nearest neighbor (two-body) and shared neighbor (three-body)
configurations. The CPDF is introduced to improve a Helmholtz free energy
method based on space partitions. We derive exact expressions of the CPDF and
various associated quantities for randomly distributed, non-interacting points
at Euclidean spaces of one, two and three dimensions. Results may be of
interest in many diverse scientific fields, from fluid physics to social and
biological sciences.Comment: 12 pages, 11 figures, v2: new section, appendix and references, plus
some other minor changes; to be published in Phys. Rev.
Theoretical UBVRI colors of iron core white dwarfs
We explore photometric properties of hypothetical iron core white dwarfs and
compute their expected colors in UBVRI Johnson broadband system. Atmospheres of
iron core WDs in this paper consist of pure iron covered by a pure hydrogen
layer of an arbitrary column mass. LTE model atmospheres and theoretical
spectra are calculated on the basis of Los Alamos TOPS opacities and the
equation of state from the OPAL project, suitable for nonideal Fe and H gases.
We have also computed UBVRI colors of the models and determined an area on the
B-V vs. U-B and U-B vs. V-I planes, occupied by both pure Fe, and pure H model
atmospheres of WD stars. Finally, we search for iron core white dwarf
candidates in the available literature.Comment: 13 pages, 12 figures, Astronomy & Astrophysics (2003) in prin
Gender balance in ECEC : why is there s little progres?
Social attitudes about male participation in the upbringing of children have changed considerably over the past few decades. Men are now seen as important for children’s development and learning. Research from many countries worldwide shows that in early childhood care and education (ECEC), male workers are welcomed by female colleagues and parents. In the last two decades there have been initiatives for more men in ECEC in several European countries.
Nevertheless the proportion of male workers ECEC remains low worldwide. This article questions the persisting gender imbalance in ECEC and analyzes ambivalences regarding more men in the field. Based on recent gender theory, efforts and limits of strategies for more male students and workers in ECEC in Belgium, Norway and Germany are discussed. It is concluded that deeply held gendered attitudes and practices in the field of care and educational work with young children have to be put into question. More space in ECEC for embodied
subjectivities is needed to overcome essentialist conceptions of differences between body and mind, women and men
The compatibility of circularity and national dietary recommendations for animal products in five European countries: a modelling analysis on nutritional feasibility, climate impact, and land use
BACKGROUND
National food-based dietary guidelines (FBDGs) are generally designed from a human health perspective and often disregard sustainability aspects. Circular food production systems are a promising solution to achieve sustainable healthy diets. In such systems, closing nutrient cycles where possible and minimising external inputs contribute to reducing environmental impacts. This change could be made by limiting livestock feed to available low-opportunity-cost biomass (LOCB). We examined the compatibility of national dietary guidelines for animal products with livestock production on the basis of the feed supplied by available LOCB.
METHODS
We investigated whether the national dietary recommendations for animal products for Bulgaria, Malta, the Netherlands, Sweden, and Switzerland could be met with domestically available LOCB. We used an optimisation model that allocates feed resources to different species of farm animals. Of the resulting scenarios, we assessed the nutritional feasibility, climate impact, and land use.
FINDINGS
Our results showed the environmental benefits of reducing the recommended animal products in the FBDGs, and that animal products from LOCB could provide between 22% (Netherlands) and 47% (Switzerland) of total protein contributions of the FBDGs. This range covers a substantial part of the nutritional needs of the studied populations. To fully meet these needs, consumption of plant-based food could be increased.
INTERPRETATION
Our results contribute to the discussion of what quantities of animal products in dietary guidelines are compatible with circular food systems. Thus, national dietary recommendations for animal products should be revised and recommended quantities lowered. This finding is consistent with recent efforts to include sustainability criteria in dietary guidelines.
FUNDING
Swiss National Science Foundation and the Dutch Research Council
- …