7,705 research outputs found
Diversity in parasitic nematode genomes: the microRNAs of Brugia pahangi and Haemonchus contortus are largely novel
<b>BACKGROUND:</b>
MicroRNAs (miRNAs) play key roles in regulating post-transcriptional gene expression and are essential for development in the free-living nematode Caenorhabditis elegans and in higher organisms. Whether microRNAs are involved in regulating developmental programs of parasitic nematodes is currently unknown. Here we describe the the miRNA repertoire of two important parasitic nematodes as an essential first step in addressing this question.
<b>RESULTS:</b>
The small RNAs from larval and adult stages of two parasitic species, Brugia pahangi and Haemonchus contortus, were identified using deep-sequencing and bioinformatic approaches. Comparative analysis to known miRNA sequences reveals that the majority of these miRNAs are novel. Some novel miRNAs are abundantly expressed and display developmental regulation, suggesting important functional roles. Despite the lack of conservation in the miRNA repertoire, genomic positioning of certain miRNAs within or close to specific coding genes is remarkably conserved across diverse species, indicating selection for these associations. Endogenous small-interfering RNAs and Piwi-interacting (pi)RNAs, which regulate gene and transposon expression, were also identified. piRNAs are expressed in adult stage H. contortus, supporting a conserved role in germline maintenance in some parasitic nematodes.
<b>CONCLUSIONS:</b>
This in-depth comparative analysis of nematode miRNAs reveals the high level of divergence across species and identifies novel sequences potentially involved in development. Expression of novel miRNAs may reflect adaptations to different environments and lifestyles. Our findings provide a detailed foundation for further study of the evolution and function of miRNAs within nematodes and for identifying potential targets for intervention
Norms and Factorial Invariance of the Athletic Identity Measurement Scale (AIMS)
This study examined the factorial invariance of the Athletic Identity Measurement Scale (AIMS; Brewer, Van Raalte, & Linder, 1993) and developed norms for its future use. A sample of 2,856 participants was assembled from multiple administrations of the AIMS over the past 10 years. The total sample was divided into two samples: a derivation sample (n = 1,462) and a validation sample (n = 1,394). The samples were stratified to insure equivalence in gender and varsity athlete/non-athlete composition. No significant differences were detected between the derivation and validation samples in AIMS item mean scores or demographic variables (all ps>.10). Results indicated that a multidimensional model in which three highly correlated first order factors (social identity, exclusivity, and negative affectivity) are subordinate to a higher order athletic identity factor demonstrated factorial invariance across genders and athletic statuses. Confirmatory factor analytic (CFA) methods were performed on the derivation sample data to examine four AIMS models (the original uni-dimensional model and three multidimensional models, designated Models A, B, C, and D) that have been previously proposed and investigated in the literature. The results of these analyses, which are described in the Appendix, supported the development of a new higher-order model, Model E, which consists of seven items. The findings suggested that a 7-item composite AIMS score is appropriate for assessing athletic identity in both men and women. Applications of the AIMS with student-athletes were discussed
Effects of Transferable Skills Workshops on the Career Self-Efficacy of College Student-Athletes
This study was designed to investigate the effects of two types of transferable skills workshops on the career self-efficacy of intercollegiate student-athletes. Participants were 79 college student-athletes (45 males [30 football players and 15 basketball players] and 34 females [14 softball players and 20 soccer players]) enrolled at a small NCAA Division III institution. Student-athletes (N=79) were randomly assigned to one of three conditions: (a) a control condition that involved viewing a video on sports nutrition, (b) an unaugmented transferable skills workshop that was based on the model suggested by Petitpas and Schwartz (1989), and (c) an augmented transferable skills workshop similar to the unaugmented workshop but including completion of a self-report inventory designed to help athletes identify sport-related skills that can transfer to other domains. All participants completed the Career Decision Self-Efficacy Short-Form (COSE-SF; Betz & Taylor, 200 I) before and after the workshops. Analyses of covariance (ANCOVAs) with COSE-SF pretest scores as a covariate revealed that the augmented transferable skills workshop produced significantly greater increases in career self-efficacy than the unaugmented transferable skills workshop and the control condition. Paired samples t-tests indicated that both transferable skills workshops, but not the control condition, produced statistically significant gains in career self-efficacy. The results suggest that both transferable skills workshops can have a positive influence on the career self-efficacy of student-athletes and that a standardized transferable skills inventory can be a helpful tool in enhancing the ability of student-athletes to identify transferable skills that can increase their career self-efficacy. The career self-efficacy level of student-athletes who participated in the transferable
skills workshops increased significantly compared to that of the control group.
In addition, participants who completed the TSI as part of their transferable skills
workshop showed higher levels of career self-efficacy than student-athletes who did
not complete the TSI
College Adjustment of Football Players: Predictors of First Semester Adjust to College among NCAA Division III Intercollegiate Football Players
This study examined predictors of first-semester adjustment to college among 48 first-year intercollegiate football players. Participants completed measures oflife stress, social support, quality of their relationship with parents, quality of their roommate relationship, sport satisfaction, athletic identity, and adjustment to college near the end of the first semester. The predictor variables accounted for 43% of the variance in adjustment to college, with quality of the roommate relationship and sport satisfaction emerging as significant (p < .05) predictors of adjustment. The results highlight the role of social and sport-related factors in how well first-year intercollegiate football players adjust to college. Recommendations for facilitating positive adjustment were provided. The more favorably participants perceived the relationship with their roommates and the more satisfied they were with their involvement in football, the better their adjustment near the end of the first semester of college. Contrary to the hypothesized pattern of results, however, factors found previously to relate to adjustment to college in the general student body (i.e., life stress, social support, and relationship with parents) were not associated with the football players' adjustment to college. Social support did not moderate the relationship between life stress and adjustment, and athletic identity did not moderate the relationship between sport satisfaction and adjustment. The failure of life stress, social support, and parent relationship to predict adjustment to college among first-year intercollegiate football players is surprising in light of research documenting associations between these variables and adjustment to college for the general student population (Compas et al., 1986; Holmbeck & Wandrei,1993; Prancer et al., 2000; Pratt et al., 2000; Wintre & Yaffe, 2000)
Common Cause Failure Modeling: Aerospace Versus Nuclear
Aggregate nuclear plant failure data is used to produce generic common-cause factors that are specifically for use in the common-cause failure models of NUREG/CR-5485. Furthermore, the models presented in NUREG/CR-5485 are specifically designed to incorporate two significantly distinct assumptions about the methods of surveillance testing from whence this aggregate failure data came. What are the implications of using these NUREG generic factors to model the common-cause failures of aerospace systems? Herein, the implications of using the NUREG generic factors in the modeling of aerospace systems are investigated in detail and strong recommendations for modeling the common-cause failures of aerospace systems are given
Trapped-ion probing of light-induced charging effects on dielectrics
We use a string of confined Ca ions to measure perturbations to a
trapping potential which are caused by light-induced charging of an
anti-reflection coated window and of insulating patches on the ion-trap
electrodes. The electric fields induced at the ions' position are characterised
as a function of distance to the dielectric, and as a function of the incident
optical power and wavelength. The measurement of the ion-string position is
sensitive to as few as elementary charges per on the
dielectric at distances of order millimetres, and perturbations are observed
for illumination with light of wavelengths as long as 729\,nm. This has
important implications for the future of miniaturised ion-trap experiments,
notably with regards to the choice of electrode material, and the optics that
must be integrated in the vicinity of the ion. The method presented can be
readily applied to the investigation of charging effects beyond the context of
ion trap experiments.Comment: 11 pages, 5 figure
Harnessing Single Cell Sorting to Identify Cell Division Genes and Regulators in Bacteria
Cell division is an essential cellular process that requires an array of known and unknown proteins for its spatial and temporal regulation. Here we develop a novel, high-throughput screening method for the identification of bacterial cell division genes and regulators. The method combines the over-expression of a shotgun genomic expression library to perturb the cell division process with high-throughput flow cytometry sorting to screen many thousands of clones. Using this approach, we recovered clones with a filamentous morphology for the model bacterium, Escherichia coli. Genetic analysis revealed that our screen identified both known cell division genes, and genes that have not previously been identified to be involved in cell division. This novel screening strategy is applicable to a wide range of organisms, including pathogenic bacteria, where cell division genes and regulators are attractive drug targets for antibiotic development. © 2013 Burke et al
Charged Scalar Particles and Leptonic Decay
Charged scalar particles introduced in some extensions of the standard model
can induce leptonic decay at tree level. We find that with some charged
SU(2)-singlet scalar particles, like ones introduced in Zee-type models,
leptonic decay width is always smaller than what is predicted by the standard
model, therefore they may offer a natural solution to decay puzzle. To
be more specific, we examine some Zee-type models in detail to see if at the
same time they are acceptable in particle physics, cosmology and astrophysics.
It is shown that decay data do put some constrains on these models.Comment: ICTP Report No. IC/93/31, 12 pages, Latex, one figure is not
included, it is available upon deman
Microstructural analysis of phase separation in iron chalcogenide superconductors
The interplay between superconductivity, magnetism and crystal structure in
iron-based superconductors is a topic of great interest amongst the condensed
matter physics community as it is thought to be the key to understanding the
mechanisms responsible for high temperature superconductivity. Alkali metal
doped iron chalcogenide superconductors exhibit several unique characteristics
which are not found in other iron-based superconducting materials such as
antiferromagnetic ordering at room temperature, the presence of ordered iron
vacancies and high resistivity normal state properties. Detailed
microstructural analysis is essential in order to understand the origin of
these unusual properties. Here we have used a range of complementary scanning
electron microscope based techniques, including high-resolution electron
backscatter di raction mapping, to assess local variations in composition and
lattice parameter with high precision and sub-micron spatial resolution. Phase
separation is observed in the Csx Fe2-ySe2 crystals, with the minor phase
distributed in a plate-like morphology throughout the crystal. Our results are
consistent with superconductivity occurring only in the minority phase.Comment: Accepted for publication in a special edition of Supercond. Sci.
Techno
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