4,254 research outputs found
The pMSSM Interpretation of LHC Results Using Rernormalization Group Invariants
The LHC has started to constrain supersymmetry-breaking parameters by setting
bounds on possible colored particles at the weak scale. Moreover, constraints
from Higgs physics, flavor physics, the anomalous magnetic moment of the muon,
as well as from searches at LEP and the Tevatron have set additional bounds on
these parameters. Renormalization Group Invariants (RGIs) provide a very useful
way of representing the allowed parameter space by making direct connection
with the values of these parameters at the messenger scale. Using a general
approach, based on the pMSSM parametrization of the soft supersymmetry-breaking
parameters, we analyze the current experimental constraints to determine the
probability distributions for the RGIs. As examples of their application, we
use these distributions to analyze the question of Gaugino Mass Unification and
to probabilistically determine the parameters of General and Minimal Gauge
Mediation with arbitrary Higgs mass parameters at the Messenger Scale.Comment: 38 pages, 10 figure
Sexual Behavior of Immature Tibetan Macaques (\u3ci\u3eMacaca thibetana\u3c/i\u3e)
Tibetan macaque sociosexual behavior begins in infancy, and comprises many of their initial interactions with other group members as infants. Tibetan macaques possess a large sociosexual behavioral repertoire, including a behavior called bridging, which involves infants and juveniles, and is found in only four species. Immature macaques differ in the types, rate, and partner preferences across a variety of behaviors. This study compared rates of sexual behavior among four age and sex classes of 26 immature Tibetan macaques at Mt. Huangshan, China. A total of 643 sex behaviors were observed and evaluated for 5 parameters: total sex behavior rates, initiation rates, rates of different types of sexual behavior, partner preference, and rates within different social contexts. Nine types of sex behaviors were observed with bridging being the most common (n = 179) and self-genital manipulation being the least common (n = 18)(H7 = 38.6, p \u3c 0.05). Sex behaviors occurred at the highest rate within spontaneous (2.9 sex behaviors per hour) and play (2.2 sex behaviors per hour) social contexts relative to grooming, aggressive, and self-directed contexts (H4 = 72.4, p \u3c 0.05). Generally, younger males exhibited higher rates of sex behavior relative to other immature classes across all five aspects, and younger females exhibited lower rates of sex behavior relative to other immature classes across all five aspects. Immature Tibetan macaques engage in many sex behaviors with both immature and adult group members. Further studies are needed on the long-term effects of immature sexual behavior regarding its function and influence on social rank and reproductive success
Severe Lumbar Disability Is Associated With Decreased Psoas Cross-Sectional Area in Degenerative Spondylolisthesis
Study Design: Retrospective cohort. Objectives: Alterations in lumbar paraspinal muscle cross-sectional area (CSA) may correlate with lumbar pathology. The purpose of this study was to compare paraspinal CSA in patients with degenerative spondylolisthesis and severe lumbar disability to those with mild or moderate lumbar disability, as determined by the Oswestry Disability Index (ODI). Methods: We retrospectively reviewed the medical records of 101 patients undergoing lumbar fusion for degenerative spondylolisthesis. Patients were divided into ODI score ≤40 (mild/moderate disability, MMD) and ODI score \u3e40 (severe disability, SD) groups. The total CSA of the psoas and paraspinal muscles were measured on preoperative magnetic resonance imaging (MRI). Results: There were 37 patients in the SD group and 64 in the MMD group. Average age and body mass index were similar between groups. For the paraspinal muscles, we were unable to demonstrate any significant differences in total CSA between the groups. Psoas muscle CSA was significantly decreased in the SD group compared with the MMD group (1010.08 vs 1178.6 mm2, P =.041). Multivariate analysis found that psoas CSA in the upper quartile was significantly protective against severe disability (P =.013). Conclusions: We found that patients with severe lumbar disability had no significant differences in posterior lumbar paraspinal CSA when compared with those with mild/moderate disability. However, severely disabled patients had significantly decreased psoas CSA, and larger psoas CSA was strongly protective against severe disability, suggestive of a potential association with psoas atrophy and worsening severity of lumbar pathology. © The Author(s) 2018
Radio Variability of Radio Quiet and Radio Loud Quasars
The majority of quasars are weak in their radio emission, with flux densities
comparable to those in the optical, and energies far lower. A small fraction,
about 10%, are hundreds to thousands of times stronger in the radio.
Conventional wisdom holds that there are two classes of quasars, the radio
quiets and radio louds, with a deficit of sources having intermediate power.
Are there really two separate populations, and if so, is the physics of the
radio emission fundamentally different between them? This paper addresses the
second question, through a study of radio variability across the full range of
radio power, from quiet to loud. The basic findings are that the root mean
square amplitude of variability is independent of radio luminosity or
radio-to-optical flux density ratio, and that fractionally large variations can
occur on timescales of months or less in both radio quiet and radio loud
quasars. Combining this with similarities in other indicators, such as radio
spectral index and the presence of VLBI-scale components, leads to the
suggestion that the physics of radio emission in the inner regions of all
quasars is essentially the same, involving a compact, partially opaque core
together with a beamed jet.Comment: 32 pages, 9 figures. Astrophysical Journal, in pres
Stable hydrogenated graphene edge types: Normal and reconstructed Klein edges
Hydrogenated graphene edges are assumed to be either armchair, zigzag or a
combination of the two. We show that the zigzag is not the most stable fully
hydrogenated structure along the direction. Instead hydrogenated Klein
and reconstructed Klein based edges are found to be energetically more
favourable, with stabilities approaching that of armchair edges. These new
structures "unify" graphene edge topology, the most stable flat hydrogenated
graphene edges always consisting of pairwise bonded C2H4 edge groups,
irrespective the edge orientation. When edge rippling is included, CH3 edge
groups are most stable. These new fundamental hydrogen terminated edges have
important implications for graphene edge imaging and spectroscopy, as well as
mechanisms for graphene growth, nanotube cutting, and nanoribbon formation and
behaviour.Fundação para a Ciência e a Tecnologia (FCT
Prospective surveillance of invasive group a streptococcal disease, Fiji, 2005-2007.
We undertook a prospective active surveillance study of invasive group A streptococcal (GAS) disease in Fiji over a 23-month period, 2005-2007. We identified 64 cases of invasive GAS disease, which represents an average annualized all-ages incidence of 9.9 cases/100,000 population per year (95% confidence interval [CI] 7.6-12.6). Rates were highest in those >65 years of age and in those <5 years, particularly in infants, for whom the incidence was 44.9/100,000 (95% CI 18.1-92.5). The case-fatality rate was 32% and was associated with increasing age and underlying coexisting disease, including diabetes and renal disease. Fifty-five of the GAS isolates underwent emm sequence typing; the types were highly diverse, with 38 different emm subtypes and no particular dominant type. Our data support the view that invasive GAS disease is common in developing countries and deserves increased public health attention
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