332 research outputs found
CP Violation in Supersymmetry with Effective Minimal Flavour Violation
We analyze CP violation in supersymmetry with Effective Minimal Flavour
Violation, as recently proposed in arXiv:1011.0730. Unlike the case of standard
Minimal Flavour Violation, we show that all the phases allowed by the flavour
symmetry can be sizable without violating existing Electric Dipole Moment
constraints, thus solving the SUSY CP problem. The EDMs at one and two loops
are precisely analyzed as well as their correlations with the expected CP
asymmetries in B physics.Comment: 22 pages, 7 figures. v2: Discussion in section 2 extended,
conclusions unchanged. Matches published versio
Molecular Gas in Spiral Galaxies
In this review, I highlight a number of recent surveys of molecular gas in
nearby spiral galaxies. Through such surveys, more complete observations of the
distribution and kinematics of molecular gas have become available for galaxies
with a wider range of properties (e.g., brightness, Hubble type, strength of
spiral or bar structure). These studies show the promise of both
interferometers and single-dish telescopes in advancing our general
understanding of molecular gas in spiral galaxies. In particular, I highlight
the contributions of the recent BIMA Survey of Nearby Galaxies (SONG).Comment: 8 pages, 1 figure. To appear in the proceedings of the 4th
Cologne-Bonn-Zermatt-Symposium, "The Dense Interstellar Medium in Galaxies",
which was held in Zermatt, Switzerland in September 200
Event-related potential studies of post-traumatic stress disorder: a critical review and synthesis
Despite the sparseness of the currently available data, there is accumulating evidence of information processing impairment in post-traumatic stress disorder (PTSD). Studies of event-related potentials (ERPs) are the main tool in real time examination of information processing. In this paper, we sought to critically review the ERP evidence of information processing abnormalities in patients with PTSD. We also examined the evidence supporting the existence of a relationship between ERP abnormalities and symptom profiles or severity in PTSD patients. An extensive Medline search was performed. Keywords included PTSD or post-traumatic stress disorder, electrophysiology or EEG, electrophysiology, P50, P100, N100, P2, P200, P3, P300, sensory gating, CNV (contingent negative variation) and MMN (mismatch negativity). We limited the review to ERP adult human studies with control groups which were reported in the English language. After applying our inclusion-exclusion review criteria, 36 studies were included. Subjects exposed to wide ranges of military and civilian traumas were studied in these reports. Presented stimuli were both auditory and visual. The most widely studied components included P300, P50 gating, N100 and P200. Most of the studies reported increased P300 response to trauma-related stimuli in PTSD patients. A smaller group of studies reported dampening of responses or no change in responses to trauma-related and/or unrelated stimuli. P50 studies were strongly suggestive of impaired gating in patients with PTSD. In conclusion, the majority of reports support evidence of information processing abnormalities in patients with PTSD diagnosis. The predominance of evidence suggests presence of mid-latency and late ERP components differences in PTSD patients in comparison to healthy controls. Heterogeneity of assessment methods used contributes to difficulties in reaching firm conclusions regarding the nature of these differences. We suggest that future ERP-PTSD studies utilize standardized assessment scales that provide detailed information regarding the symptom clusters and the degree of symptom severity. This would allow assessment of electrophysiological indices-clinical symptoms relationships. Based on the available data, we suggest that ERP abnormalities in PTSD are possibly affected by the level of illness severity. If supported by future research, ERP studies may be used for both initial assessment and treatment follow-up
Changes in visual function after intraocular pressure reduction using antiglaucoma medications
Purpose To evaluate the change in visual function after starting glaucoma treatment and correlate this to a decrease in intraocular pressure (IOP) in primary open-angle glaucoma patients.Methods A prospective, randomized clinical trial was carried out involving 54 glaucoma patients (54 eyes). After inclusion, patients randomly received timolol maleate 0.5%, brimonidine tartrate 0.2%, or travoprost 0.004% in one randomly selected eye. Patients underwent Goldmann applanation tonometry, visual acuity test, standard automated perimetry (SAP), visual quality perception test (visual analogue scale), and contrast sensitivity (CS) test, in a random order before and after the 4-week glaucoma treatment.Results There were statistically significant changes in IOP (mean change [standard deviation], 7.8 [3.6] mmHg, P 0.001), SAP mean deviation index (0.84 [2.45] dB, P = 0.02), visual quality perception (0.56 [1.93], P = 0.045), and CS at frequencies of 12 cycles/degree (0.10 [0.37], P = 0.03) and 18 cycles/degree (0.18 [0.42], P = 0.02) after the 4-week treatment when compared with baseline. No statistically significant differences were found between the treatment groups in visual function changes after treatment (P > 0.40). No significant correlations between IOP reduction and changes in visual function were found (P > 0.30).Conclusions Visual quality perception, visual field mean deviation index, and CS at higher frequencies improve after starting glaucoma therapy. However, no correlation was found between IOP reduction and changes in visual function, and no differences were found in visual function when the three medications studied were compared. Eye (2009) 23, 1081-1085; doi:10.1038/eye.2008.226; published online 1 August 2008Universidade Federal de São Paulo, Glaucoma Serv, Dept Ophthalmol, BR-01404001 São Paulo, BrazilUniversidade Federal de São Paulo, Glaucoma Serv, Dept Ophthalmol, BR-01404001 São Paulo, BrazilWeb of Scienc
MFV Reductions of MSSM Parameter Space
The 100+ free parameters of the minimal supersymmetric standard model (MSSM)
make it computationally difficult to compare systematically with data,
motivating the study of specific parameter reductions such as the cMSSM and
pMSSM. Here we instead study the reductions of parameter space implied by using
minimal flavour violation (MFV) to organise the R-parity conserving MSSM, with
a view towards systematically building in constraints on flavour-violating
physics. Within this framework the space of parameters is reduced by expanding
soft supersymmetry-breaking terms in powers of the Cabibbo angle, leading to a
24-, 30- or 42-parameter framework (which we call MSSM-24, MSSM-30, and MSSM-42
respectively), depending on the order kept in the expansion. We provide a
Bayesian global fit to data of the MSSM-30 parameter set to show that this is
manageable with current tools. We compare the MFV reductions to the
19-parameter pMSSM choice and show that the pMSSM is not contained as a subset.
The MSSM-30 analysis favours a relatively lighter TeV-scale pseudoscalar Higgs
boson and with multi-TeV sparticles.Comment: 2nd version, minor comments and references added, accepted for
publication in JHE
Magnetic resonance imaging findings in 46 elbows with a radial head fracture
Radial head fractures are common, and may be associated with other injuries of clinical importance. We present the results of a standard additional MRI scan for patients with a radial head fracture. PATIENTS AND METhods: 44 patients (mean age 47 years) with 46 radial head fractures underwent MRI. 17 elbows had a Mason type-I fracture, 23 a Mason type-II fracture, and 6 elbows had a Mason type-III fracture. Associated injuries were found in 35 elbows: 28 elbows had a lateral collateral ligament lesion, 18 had capitellar injury, 1 had a coronoid fracture, and 1 elbow had medial collateral ligament injury. The incidence of associated injuries with radial head fractures found with MRI was high. The clinical relevance should be investigate
Probing the charged Higgs boson at the LHC in the CP-violating type-II 2HDM
We present a phenomenological study of a CP-violating two-Higgs-doublet Model
with type-II Yukawa couplings at the Large Hadron Collider (LHC). In the light
of recent LHC data, we focus on the parameter space that survives the current
and past experimental constraints as well as theoretical bounds on the model.
Once the phenomenological scenario is set, we analyse the scope of the LHC in
exploring this model through the discovery of a charged Higgs boson produced in
association with a W boson, with the former decaying into the lightest neutral
Higgs and a second W state, altogether yielding a b\bar b W^+W^- signature, of
which we exploit the W^+W^- semileptonic decays.Comment: 37 pages, 16 figures; v2 updated treatment of LHC constraint
Single-Scale Natural SUSY
We consider the prospects for natural SUSY models consistent with current
data. Recent constraints make the standard paradigm unnatural so we consider
what could be a minimal extension consistent with what we now know. The most
promising such scenarios extend the MSSM with new tree-level Higgs interactions
that can lift its mass to at least 125 GeV and also allow for flavor-dependent
soft terms so that the third generation squarks are lighter than current bounds
on the first and second generation squarks. We argue that a common feature of
almost all such models is the need for a new scale near 10 TeV, such as a scale
of Higgsing or confinement of a new gauge group. We consider the question
whether such a model can naturally derive from a single mass scale associated
with supersymmetry breaking. Most such models simply postulate new scales,
leaving their proximity to the scale of MSSM soft terms a mystery. This
coincidence problem may be thought of as a mild tuning, analogous to the usual
mu problem. We find that a single mass scale origin is challenging, but suggest
that a more natural origin for such a new dynamical scale is the gravitino
mass, m_{3/2}, in theories where the MSSM soft terms are a loop factor below
m_{3/2}. As an example, we build a variant of the NMSSM where the singlet S is
composite, and the strong dynamics leading to compositeness is triggered by
masses of order m_{3/2} for some fields. Our focus is the Higgs sector, but our
model is compatible with a light stop (with the other generation squarks heavy,
or with R-parity violation or another mechanism to hide them from current
searches). All the interesting low-energy mass scales, including linear terms
for S playing a key role in EWSB, arise dynamically from the single scale
m_{3/2}. However, numerical coefficients from RG effects and wavefunction
factors in an extra dimension complicate the otherwise simple story.Comment: 32 pages, 3 figures; version accepted by JHE
Comparability of Results from Pair and Classical Model Formulations for Different Sexually Transmitted Infections
The “classical model” for sexually transmitted infections treats partnerships as instantaneous events summarized by partner change rates, while individual-based and pair models explicitly account for time within partnerships and gaps between partnerships. We compared predictions from the classical and pair models over a range of partnership and gap combinations. While the former predicted similar or marginally higher prevalence at the shortest partnership lengths, the latter predicted self-sustaining transmission for gonorrhoea (GC) and Chlamydia (CT) over much broader partnership and gap combinations. Predictions on the critical level of condom use (Cc) required to prevent transmission also differed substantially when using the same parameters. When calibrated to give the same disease prevalence as the pair model by adjusting the infectious duration for GC and CT, and by adjusting transmission probabilities for HIV, the classical model then predicted much higher Cc values for GC and CT, while Cc predictions for HIV were fairly close. In conclusion, the two approaches give different predictions over potentially important combinations of partnership and gap lengths. Assuming that it is more correct to explicitly model partnerships and gaps, then pair or individual-based models may be needed for GC and CT since model calibration does not resolve the differences
Paternally expressed, imprinted insulin-like growth factor-2 in chorionic villi correlates significantly with birth weight
Context: Fetal growth involves highly complex molecular pathways. IGF2 is a key paternally expressed growth hormone that is critical for in utero growth in mice. Its role in human fetal growth has remained ambiguous, as it has only been studied in term tissues. Conversely the maternally expressed growth suppressor, PHLDA2, has a significant negative correlation between its term placental expression and birth weight. Objective: The aim of this study is to address the role in early gestation of expression of IGF1, IGF2, their receptors IGF1R and IGF2R, and PHLDA2 on term birth weight. Design: Real-time quantitative PCR was used to investigate mRNA expression of IGF1, IGF2, IGF1R, IGF2R and PHLDA2 in chorionic villus samples (CVS) (n = 260) collected at 11–13 weeks’ gestation. Expression was correlated with term birth weight using statistical package R including correction for several confounding factors. Results: Transcript levels of IGF2 and IGF2R revealed a significant positive correlation with birth weight (0.009 and 0.04, respectively). No effect was observed for IGF1, IGF1R or PHLDA2 and birth weight. Critically, small for gestational age (SGA) neonates had significantly lower IGF2 levels than appropriate for gestational age neonates (p = 3?661027 ). Interpretation: Our findings show that IGF2 mRNA levels at 12 weeks gestation could provide a useful predictor of future fetal growth to term, potentially predicting SGA babies. SGA babies are known to be at a higher risk for type 2 diabetes. This research reveals an imprinted, parentally driven rheostat for in utero growth
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