420 research outputs found
The Examination of Grazing Intensity Effects on Capability of Water Influence in Rangelands Soil--A Case Study: Alpine Rangelands in North of Iran (Alborz Mountains)
Seroprevalence of varicella zoster virus antibody among young women before marriage in Sanandaj, Iran
Background and Objectives: Varicella Zoster Virus (VZV) infection in pregnant women can cause complications for the mother and fetus. The aim of this study was to assess the immunity against VZV among young women before marriage. Materials and Methods: In this cross-sectional study 250 women attending health centers in Sanandaj, Iran, for pre-marital medical check-up were randomly selected. The VZV IgG measured by ELISA and demographic characteristics of participants including their age, place of residence, number of siblings, occupation, education and history of chickenpox were also recorded. Data were analyzed using R statistical software. Association between VZV infection and participants� characteristics was assessed using Chi-square and Fisher's exact tests. Results: Out of 250 participants, 178 individuals (71.2) diagnosed as antibody positive and 72 (28.8) negative. Our findings revealed that the immunity against VZV increased with individuals� age (P<0.0001) and their number of siblings (P= 0.03). Significant association was found between history of chickenpox and immunity (P <0.001). Positive and negative predictive values of self-reported history of chickenpox obtained by 94.60 and 49.25, respectively. Conclusion: A notable percentage of women were found to be susceptible to VZV, hence they are at risk of getting infected during pregnancy which in turn may result in fetus abnormalities. Screening the immunity and further studies on the need of vaccination before marriage are recommended. © 2016, Tehran University of Medical Science. All rights reserved
Correlation energy of the spin-polarized electron liquid by quantum Monte Carlo
Variational and diffusion quantum Monte Carlo (VMC and DMC) methods with
Slater-Jastrow-backflow trial wave functions are used to study the
spin-polarized three-dimensional uniform electron fluid. We report ground state
VMC and DMC energies in the density range .
Finite-size errors are corrected using canonical-ensemble twist-averaged
boundary conditions and extrapolation of the twist-averaged energy per particle
calculated at three system sizes (N=113, 259, and 387) to the thermodynamic
limit of infinite system size. The DMC energies in the thermodynamic limit are
used to parameterize a local spin density approximation correlation function
for inhomogeneous electron systems.Comment: arXiv admin note: substantial text overlap with arXiv:2209.1022
Correlation energy of the paramagnetic electron gas at the thermodynamic limit
The variational and diffusion quantum Monte Carlo methods are used to
calculate the correlation energy of the paramagnetic three-dimensional
homogeneous electron gas at intermediate to high density. Ground state energies
in finite cells are determined using Slater-Jastrow-backflow trial wave
functions, and finite-size errors are removed using twist-averaged boundary
conditions and extrapolation of the energy per particle to the thermodynamic
limit of infinite system size. Our correlation energies in the thermodynamic
limit are lower (i.e., more negative, and therefore more accurate according to
the variational principle) than previous results, and can be used for the
parameterization of density functionals to be applied to high-density systems
Sustainable Rangeland Management Using A Multi-Fuzzy Model: How To Deal With Heterogeneous Experts’ Knowledge
While fuzzy specialists usually use homogeneous experts’ knowledge to construct fuzzy models,
it is much more difficult to deal with knowledge elicited from a heterogeneous group of experts.
This issue especially holds in the area of the sustainable rangeland management. One way to
deal with the diversity of opinions is to develop a fuzzy system for all experts and to combine all
these so-called primary systems into one multi-fuzzy model. To derive each of the primary fuzzy
systems using the knowledge of a group of administrative experts, several semi-structured
interviews were held in three different areas of the Fars province in Southwest Iran. In order to
find the final output of the multi-fuzzy model, we applied different ‘voting’ methods. The first
method simply uses the arithmetic average of the primary outputs as the final output of the multifuzzy
model. This final output represents an estimation of the Right Rate of Stocking. We also
propose other (un)supervised voting methods. Most importantly, by harmonizing the primary
outputs such that outliers get less emphasis, we introduce an unsupervised voting method
calculating a weighted estimate of the Right Rate of Stocking. This harmonizing method is
expected to provide a new useful tool for policymakers in order to deal with heterogenity in
experts’ opinions: it is especially useful in cases where little field data is available and one is
forced to rely on experts’ knowledge only. By constructing the three fuzzy models based on the
elicitation of heterogeneous experts’ knowledge, our study shows the multidimensional
vaguenesses that exist in sustainable rangeland management. Finally, by comparing the final
Right Rate of Stocking with its medium range, this study proves the existence of overgrazing in
pastures of the three regions of the Fars province in Southwest Iran
Defects in Crystalline Packings of Twisted Filament Bundles: II. Dislocations and Grain Boundaries
Twisted and rope-like assemblies of filamentous molecules are common and
vital structural elements in cells and tissue of living organisms. We study the
intrinsic frustration occurring in these materials between the two-dimensional
organization of filaments in cross section and out-of-plane interfilament twist
in bundles. Using non-linear continuum elasticity theory of columnar materials,
we study the favorable coupling of twist-induced stresses to the presence of
edge dislocations in the lattice packing of bundles, which leads to a
restructuring of the ground-state order of these materials at intermediate
twist. The stability of dislocations increases as both the degree of twist and
lateral bundle size grow. We show that in ground states of large bundles,
multiple dislocations pile up into linear arrays, radial grain boundaries,
whose number and length grows with bundle twist, giving rise to a rich class of
"polycrystalline" packings.Comment: 10 pages, 7 figure
Salmonella enterica serovar Typhi lipopolysaccharide O-antigen modification impact on serum resistance and antibody recognition
Salmonella enterica serovar Typhi is a human-restricted Gram-negative bacterial pathogen responsible for causing an estimated 27 million cases of typhoid fever annually, leading to 217,000 deaths, and current vaccines do not offer full protection. The O-antigen side chain of the lipopolysaccharide is an immunodominant antigen, can define host-pathogen interactions, and is under consideration as a vaccine target for some Gram-negative species. The composition of the O-antigen can be modified by the activity of glycosyltransferase (gtr) operons acquired by horizontal gene transfer. Here we investigate the role of two gtr operons that we identified in the S. Typhi genome. Strains were engineered to express specific gtr operons. Full chemical analysis of the O-antigens of these strains identified gtr-dependent glucosylation and acetylation. The glucosylated form of the O-antigen mediated enhanced survival in human serum and decreased complement binding. A single nucleotide deviation from an epigenetic phase variation signature sequence rendered the expression of this glucosylating gtr operon uniform in the population. In contrast, the expression of the acetylating gtrC gene is controlled by epigenetic phase variation. Acetylation did not affect serum survival, but phase variation can be an immune evasion mechanism, and thus, this modification may contribute to persistence in a host. In murine immunization studies, both O-antigen modifications were generally immunodominant. Our results emphasize that natural O-antigen modifications should be taken into consideration when assessing responses to vaccines, especially O-antigen-based vaccines, and that the Salmonella gtr repertoire may confound the protective efficacy of broad-ranging Salmonella lipopolysaccharide conjugate vaccines
Phase transition in Schwarzschild-de Sitter spacetime
Using a static massive spherically symmetric scalar field coupled to gravity
in the Schwarzschild-de Sitter (SdS) background, first we consider some
asymptotic solutions near horizon and their local equations of state(E.O.S) on
them. We show that near cosmological and event horizons our scalar field
behaves as a dust. At the next step near two pure de-Sitter or Schwarzschild
horizons we obtain a coupling dependent pressure to energy density ratio. In
the case of a minimally couplling this ratio is -1 which springs to the mind
thermodynamical behavior of dark energy. If having a negative pressure behavior
near these horizons we concluded that the coupling constant must be
>. Therefore we derive a new constraint on the value of our coupling .
These two different behaviors of unique matter in the distinct regions of
spacetime at present era can be interpreted as a phase transition from dark
matter to dark energy in the cosmic scales and construct a unified scenario.Comment: 7 pages,no figures,RevTex, Typos corrected and references adde
The components of workplace violence against nurses from the perspective of women working in a hospital in Tehran: a qualitative study
Background: Based on the World Health Organization (WHO), workplace violence can affect events where employees are abused, attacked or threatened in their workplace, and it also has some consequences such as safety, welfare, and health. Like other types of violence, workplace violence and aggression are an increasing phenomenon. Moreover, workplace violence not only disrupts interpersonal and organizational relationships, but it also impairs the persons self-esteem and affects their physical and mental health and well-being. Thus, this study aimed to explain the components of workplace violence against nurses from the perspective of women working in a hospital in Tehran, which was conducted through the qualitative method and content analysis. Methods: In this study Purposive sampling included 21 female nurses who were working in different wards of the hospital. Also, female nurses were selected with maximum diversity in terms of work experience, age, and the wards they were working in. in this study the semi-structured interview was the main method of data collection. The interview transcriptions were extracted and then divided into meaningful units. For strengthening and confirming the results and accuracy of the research, the author used the data acceptability, credibility, accuracy, validity, believability, verifiability, reliability, and transferability. Results: During the data analysis process of this study, the first 15 classes with the same characteristics were put together and then divided into 6 classes. Afterwards, based on the common features at a more abstract level, they were converted into 2 themes. Based on the findings, violence against women in the workplace occurs at two levels, that namely interpersonal violence and organizational coercion. Conclusion: Therefore, it is necessary for managers to commit to lay the groundwork for reducing violence in the hospital, as well as barriers to report these cases especially the hospital managers and officials should create awareness on workplace among the staff, patient and visitors and must ensure stringent actions to prevent it. © 2021, The Author(s)
- …