9,426 research outputs found
Accurate Neutralino Relic Density Computations in Supergravity Models
We investigate the question of the proper thermal averaging of neutralino
annihilation amplitudes which possess poles and thresholds, as they impact on
the calculated neutralino relic density and therefore on the cosmological
viability of supersymmetric models. We focus on two typical resonances, namely
the boson and the lightest Higgs boson (). In the context of
supergravity models with radiative electroweak symmetry breaking, an
exploration of the whole parameter space of the model is possible and the
overall relevance of these sophisticated analyses can be ascertained. As an
example we chose the minimal supergravity model since the presence of
such poles is essential to obtain a cosmologically acceptable model. We find
that the proper thermal averaging is important for individual points in
parameter space and that the fraction of cosmologically acceptable points is
increased somewhat by the accurate procedure. However, qualitatively the new
set of points is very similar to that obtained previously using the usual
series approximations to the thermal average. We conclude that all
phenomenological analyses based on the previously determined cosmologically
allowed set remain valid.Comment: 15 pages, 9 figures (available upon request as uuencoded file or
separate ps files), tex (harvmac) CTP-TAMU-14/9
Antimicrobial activity of Bursera morelensis ramírez essential oil
Background: Bursera morelensis, known as “Aceitillo”, is an endemic tree of Mexico. Infusions made from the bark of this species have been used for the treatment of skin infections and for their wound healing properties. In this work, we present the results of a phytochemical and antimicrobial investigation of the essential oil of B. morelensis.Materials and Methods: The essential oil was obtained by a steam distillation method and analyzed using GC-MS. The antibacterial and antifungal activities were evaluated.Results: GC-MS of the essential oil demonstrated the presence of 28 compounds. The principal compound of the essential oil was α-Phellandrene (32.69%). The essential oil had antibacterial activity against Gram positive and negative strains. The most sensitive strains were S. pneumoniae, V. cholerae (cc) and E. coli (MIC 0.125 mg/mL, MBC 0.25 mg/mL). The essential oil was bactericidal for V. cholera (cc). The essential oil inhibited all the filamentous fungi. F. monilifome (IC50 = 2.27 mg/mL) was the most sensitive fungal strain.Conclusions: This work provides evidence that confirms the antimicrobial activity of the B. morelensis essential oil and this is a scientific support about of traditional uses of this species.Keywords: Essential oil; Medicinal plants; Tehuacan-Cuicatlan Valley; Burseraceae; Burser
Non-Universality Effects and Dark Matter in Gravity Mediated SUSY Breaking
Dark matter detection rates for supergravity models with R parity where
supersymmetry is broken at a scale >~M_G are discussed. Non-universal soft
breaking masses in both the Higgs and squark sectors are considered, and it is
seen that these can effect rates by a factor of 10-100 when m_X <~ 65 GeV
(X=lightest neutralino) but otherwise make relatively small corrections. The
b->s+\gamma branching ratio is seen to correlate with detector event rates,
large (small) branching ratios corresponding to small (large) event rates.
Effects of precision determinations of cosmological parameters or event rate
predictions by future satellite experiments are discussed for the LCDM and the
vCDM models.Comment: LaTeX 7 pages,4 figures, requires espcrc2.sty available from
http://dept.physics.upenn.ed
The effects of advanced maternal age on T- cell subsets at the maternal- fetal interface prior to term labor and in the offspring: a mouse study
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155904/1/cei13437.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155904/2/cei13437_am.pd
Hot topics, urgent priorities, and ensuring success for racial/ethnic minority young investigators in academic pediatrics.
BackgroundThe number of racial/ethnic minority children will exceed the number of white children in the USA by 2018. Although 38% of Americans are minorities, only 12% of pediatricians, 5% of medical-school faculty, and 3% of medical-school professors are minorities. Furthermore, only 5% of all R01 applications for National Institutes of Health grants are from African-American, Latino, and American Indian investigators. Prompted by the persistent lack of diversity in the pediatric and biomedical research workforces, the Academic Pediatric Association Research in Academic Pediatrics Initiative on Diversity (RAPID) was initiated in 2012. RAPID targets applicants who are members of an underrepresented minority group (URM), disabled, or from a socially, culturally, economically, or educationally disadvantaged background. The program, which consists of both a research project and career and leadership development activities, includes an annual career-development and leadership conference which is open to any resident, fellow, or junior faculty member from an URM, disabled, or disadvantaged background who is interested in a career in academic general pediatrics.MethodsAs part of the annual RAPID conference, a Hot Topic Session is held in which the young investigators spend several hours developing a list of hot topics on the most useful faculty and career-development issues. These hot topics are then posed in the form of six "burning questions" to the RAPID National Advisory Committee (comprised of accomplished, nationally recognized senior investigators who are seasoned mentors), the RAPID Director and Co-Director, and the keynote speaker.Results/conclusionsThe six compelling questions posed by the 10 young investigators-along with the responses of the senior conference leadership-provide a unique resource and "survival guide" for ensuring the academic success and optimal career development of young investigators in academic pediatrics from diverse backgrounds. A rich conversation ensued on the topics addressed, consisting of negotiating for protected research time, career trajectories as academic institutions move away from an emphasis on tenure-track positions, how "non-academic" products fit into career development, racism and discrimination in academic medicine and how to address them, coping with isolation as a minority faculty member, and how best to mentor the next generation of academic physicians
Social and Emotional Skills in at-Risk Adolescents through Participation in Sports
(1) Background: Adolescents who are under the care of child and youth institutions are vulnerable due to factors that can include disruption to family structure or education and adverse experiences. They often experience poor or unstable support systems, leaving them at risk of delinquency. In this context, sports engagement may provide a stable structure and have positive effects in this population. Therefore, the purpose of this study was to explore the perceptions, knowledge, beliefs, and behaviors regarding social and emotional skills among at-risk adolescents, with a specific focus on their engagement in sports. (2) Methods: Ninety-six adolescents aged 12 to 17 years (66 female, 30 male), residing in child and youth care institutions across Italy, Portugal, the UK, and Turkey, participated in this study. The participants were divided into 14 focus groups, each with six to eight participants of similar ages. (3) Results: Thematic analysis revealed four main themes: Emotional causes of behavioral problems; Emotional skills to regain control; Social support makes sports worthwhile; Sport as a socio-emotional resource. (4) Conclusions: The study findings highlight that although sports create many challenging emotional situations for these adolescents, they also provides resources that may help them cope with their emotions within and beyond sports
Specific Glucoside Transporters Influence Septal Structure and Function in the Filamentous, Heterocyst-Forming Cyanobacterium Anabaena sp Strain PCC 7120
T When deprived of combined nitrogen, some filamentous cyanobacteria
contain two cell types: vegetative cells that fix CO2 through oxygenic photosynthesis
and heterocysts that are specialized in N2 fixation. In the diazotrophic filament, the
vegetative cells provide the heterocysts with reduced carbon (mainly in the form of
sucrose) and heterocysts provide the vegetative cells with combined nitrogen. Septal
junctions traverse peptidoglycan through structures known as nanopores and appear
to mediate intercellular molecular transfer that can be traced with fluorescent
markers, including the sucrose analog esculin (a coumarin glucoside) that is incorporated
into the cells. Uptake of esculin by the model heterocyst-forming cyanobacterium
Anabaena sp. strain PCC 7120 was inhibited by the -glucosides sucrose and
maltose. Analysis of Anabaena mutants identified components of three glucoside
transporters that move esculin into the cells: GlsC (Alr4781) and GlsP (All0261) are
an ATP-binding subunit and a permease subunit of two different ABC transporters,
respectively, and HepP (All1711) is a major facilitator superfamily (MFS) protein that
was shown previously to be involved in formation of the heterocyst envelope. Transfer
of fluorescent markers (especially calcein) between vegetative cells of Anabaena
was impaired by mutation of glucoside transporter genes. GlsP and HepP interact in
bacterial two-hybrid assays with the septal junction-related protein SepJ, and GlsC
was found to be necessary for the formation of a normal number of septal peptidoglycan
nanopores and for normal subcellular localization of SepJ. Therefore, beyond
their possible role in nutrient uptake in Anabaena, glucoside transporters influence
the structure and function of septal junctions.Peer reviewe
Carotenoid-based skin ornaments reflect foraging propensity in a seabird, Sula leucogaster
Carotenoid-based ornaments are common signalling features in animals. It has long been proposed that such ornaments communicate information about foraging abilities to potential mates. However, evidence linking foraging with ornamentation is largely missing from unmanipulated, free-ranging populations. To investigate this relationship, we studied a coastal population of brown booby (Sula leucogaster brewsteri), a seabird with a carotenoid-based gular skin ornament. δ13C values from both feathers and blood plasma were negatively correlated with male gular colour, indicating birds that consumed more pelagic prey in offshore locations had more ornamented skin than those that fed on nearshore, benthic prey. This relationship was supported by our GPS tracking results, which revealed longer, more offshore foraging trips among highly ornamented males. Our data show that brown booby ornaments are honest indicators of foraging propensity; a link consistent with the rarity hypothesis and potentially driven by the concentration of carotenoids found in phytoplankton versus benthic algae. Carotenoid-based ornaments may reflect foraging tendencies in animals such as coastal predators that use food webs with distinct carotenoid profiles
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