1,082 research outputs found
Higher-order scalar interactions and SM vacuum stability
Investigation of the structure of the Standard Model effective potential at
very large field strengths opens a window towards new phenomena and can reveal
properties of the UV completion of the SM. The map of the lifetimes of the
vacua of the SM enhanced by nonrenormalizable scalar couplings has been
compiled to show how new interactions modify stability of the electroweak
vacuum. Whereas it is possible to stabilize the SM by adding Planck scale
suppressed interactions and taking into account running of the new couplings,
the generic effect is shortening the lifetime and hence further destabilisation
of the SM electroweak vacuum. These findings have been illustrated with phase
diagrams of modified SM-like models. It has been demonstrated that
stabilisation can be achieved by lowering the suppression scale of higher order
operators while picking up such combinations of new couplings, which do not
deepen the new minima of the potential. Our results show the dependence of the
lifetime of the electroweak minimum on the magnitude of the new couplings,
including cases with very small couplings (which means very large effective
suppression scale) and couplings vastly different in magnitude (which
corresponds to two different suppression scales).Comment: plain Latex, 9 figure
SuSeFLAV: A program for calculating supersymmetric spectra and lepton flavor violation
We introduce the program SuSeFLAV for computing supersymmetric mass spectra
with flavor violation in various supersymmetric breaking scenarios with/without
seesaw mechanism. A short user guide summarizing the compilation, executables
and the input files is provided.Comment: 3 pages, latex, pramana style, proceedings for Lepton Photon 201
Vacuum Stability, Perturbativity, and Scalar Singlet Dark Matter
We analyze the one-loop vacuum stability and perturbativity bounds on a
singlet extension of the Standard Model (SM) scalar sector containing a scalar
dark matter candidate. We show that the presence of the singlet-doublet quartic
interaction relaxes the vacuum stability lower bound on the SM Higgs mass as a
function of the cutoff and lowers the corresponding upper bound based on
perturbativity considerations. We also find that vacuum stability requirements
may place a lower bound on the singlet dark matter mass for given singlet
quartic self coupling, leading to restrictions on the parameter space
consistent with the observed relic density. We argue that discovery of a light
singlet scalar dark matter particle could provide indirect information on the
singlet quartic self-coupling.Comment: 25 pages, 10 figures; v2 - fixed minor typos; v3 - added to text
discussions of other references, changed coloring of figures for easier black
and white viewin
Continuous culture of Perkinsus mediterraneus, a parasite of the European flat oyster Ostrea edulis, and characterization of its morphology, propagation, and extracellular proteins in vitro
Continuous in vitro cultures of Perkinsus mediterraneus were established from tissues of infected European flat oysters, Ostrea edulis. The parasite proliferated in protein-free medium and divided by schizogony in vitro. Cell morphology was similar to that observed for P. mediterraneus in tissues of naturally infected O. edulis and for other Perkinsus spp. cultured in vitro. Parasite cells enlarged approximately 8-fold when placed in alternative Ray\u27s fluid thioglycollate medium, and stained black with Lugol\u27s iodine solution, a response characteristic of Perkinsus spp. DNA sequences matched those determined previously for P. mediterraneus, and phylogenetic analyses on three different data sets indicated that this was a Perkinsus species with a close relationship to another recently described species, Perkinsus honshuensis. Parasite viability was high (\u3e 90%) in vitro, but the proliferation rate was low, with densities generally increasing 2-to-6-fold between subcultures at 6-wk intervals. Enzyme analysis of cell-free culture supernatants revealed protease-, esterase-, glycosidase-, lipase-, and phosphatase-like activities. Incubation with class-specific protease inhibitors showed that P. mediterraneus produced serine proteases, and eight proteolytic bands with molecular weights ranging from 34 to 79 kDa were detected in the supernatants by gelatin sodium dodecylsulfate-polyacrylamide gel electrophoresis
Fair scans of the seesaw. Consequences for predictions on LFV processes
Usual analyses based on scans of the seesaw parameter-space can be biassed
since they do not cover in a fair way the complete parameter-space. More
precisely, we show that in the common "R-parametrization", many acceptable
R-matrices, compatible with the perturbativity of Yukawa couplings, are
normally disregarded from the beginning, which produces biasses in the results.
We give a straightforward procedure to scan the space of complex R-matrices in
a complete way, giving a very simple rule to incorporate the perturbativity
requirement as a condition for the entries of the R-matrix, something not
considered before. As a relevant application of this, we show that the extended
believe that BR(mu --> e, gamma) in supersymmetric seesaw models depends
strongly on the value of theta_13 is an "optical effect" produced by such
biassed scans, and does not hold after a careful analytical and numerical
study. When the complete scan is done, BR(mu --> e, gamma) gets very
insensitive to theta_13. Moreover, the values of the branching ratio are
typically larger than those quoted in the literature, due to the large number
of acceptable points in the parameter-space which were not considered before.
Including (unflavoured) leptogenesis does not introduce any further dependence
on theta_13, although decreases the typical value of BR(mu --> e, gamma).Comment: 22 pages, 5 figure
Atrial fibrillation epidemiology, disparity and healthcare contacts: a population-wide study of 5.6 million individuals
Background: We aimed to evaluate atrial fibrillation occurrence, reasons for healthcare visits, mortality, causes of death and examined patterns by relative deprivation in the UK.
Methods: To study the atrial fibrillation (AF) incidence, mortality and case-fatality, we implemented a prospective cohort study with the linked electronic health records of 5.6 million population in the United Kingdom Clinical Practice Research Datalink from 1998 to 2016. A matched case-control study was used to investigate causes of hospitalisation and death comparing individuals with and without incident AF.
Results: During a median follow-up of 10.3 years, 199,433(3.6%) patients developed incident AF. Increased risk of hospitalisation for heart failure, cardiovascular conditions and infection was present among patients who later developed AF. Following an AF diagnosis, patients were frequently admitted to the hospital for heart failure, lower respiratory tract infection, chronic obstructive pulmonary disease and ischemic heart disease. One in 5 AF patients died during the first year after diagnosis, and the mortality increased to 42.7% at the fifth year. The excess deaths in AF cases compared to controls may result from cardiovascular diseases, infection and metabolic disorders. Individuals from areas with higher deprivation in socioeconomic and living status had both higher AF incidence and fatality.
Interpretation: We observed an elevated risk of hospitalisation for cardiovascular or respiratory diseases among incident AF patients, and the considerable disparity in AF burden by socioeconomic deprivation informs priorities for prevention and provision of patient care
Circulating Apolipoprotein E Concentration and Cardiovascular Disease Risk: Meta-analysis of Results from Three Studies
Background: The association of APOE genotype with circulating apolipoprotein E (ApoE) concentration and cardiovascular disease (CVD) risk is well established. However, the relationship of circulating ApoE concentration and CVD has received little attention. Methods and Findings: To address this, we measured circulating ApoE concentration in 9,587 individuals (with 1,413 CVD events) from three studies with incident CVD events: two population-based studies, the English Longitudinal Study of Ageing (ELSA) and the men-only Northwick Park Heart Study II (NPHSII), and a nested sub-study of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT). We examined the association of circulating ApoE with cardiovascular risk factors in the two population-based studies (ELSA and NPHSII) and the relationship between ApoE concentration and coronary heart disease and stroke in all three studies. Analyses were carried out within study, and, where appropriate, pooled effect estimates were derived using meta-analysis. In the population-based samples, circulating ApoE was associated with systolic blood pressure (correlation coefficient 0.08, p < 0.001, in both ELSA and NPHSII), total cholesterol (correlation coefficient 0.46 and 0.34 in ELSA and NPHSII, respectively; both p < 0.001), low-density lipoprotein cholesterol (correlation coefficient 0.30 and 0.14, respectively; both p < 0.001), high-density lipoprotein (correlation coefficient 0.16 and ?0.14, respectively; both p < 0.001), and triglycerides (correlation coefficient 0.43 and 0.46, respectivly; both p < 0.001). In NPHSII, ApoE concentration was additionally associated with apolipoprotein B (correlation coefficient 0.13, p = 0.001) and lipoprotein(a) (correlation coefficient ?0.11, p < 0.001). In the pooled analysis of ASCOT, ELSA, and NPHSII, there was no association of ApoE with CVD events; the odds ratio (OR) for CVD events per 1-standard-deviation higher ApoE concentration was 1.02 (95% CI 0.96, 1.09). After adjustment for cardiovascular risk factors, the OR for CVD per 1-standard-deviation higher ApoE concentration was 0.97 (95% CI 0.82, 1.15). Limitations of these analyses include a polyclonal method of ApoE measurement, rather than isoform-specific measurement, a moderate sample size (although larger than any other study to our knowledge and with a long lag between ApoE measures), and CVD events that may attenuate an effect. Conclusions: In the largest study to date on this question, we found no evidence of an association of circulating ApoE concentration with CVD events. The established association of APOE genotype with CVD events may be explained by isoform-specific functions as well as other mechanisms, rather than circulating concentrations of ApoE
On the importance of the 1-loop finite corrections to seesaw neutrino masses
In the standard seesaw mechanism, finite corrections to the neutrino mass
matrix arise from 1-loop self-energy diagrams mediated by a heavy neutrino. We
study in detail these corrections and demonstrate that they can be very
significant, exceeding in several cases the tree-level result. We consider the
normal and inverted hierarchy spectra for light neutrinos and compute the
finite corrections to the different elements of the neutrino mass matrix.
Special attention is paid to their dependence with the parameters of the seesaw
model. Among the cases in which the corrections can be large, we identify the
fine-tuned models considered previously in the literature, where a strong
cancellation between the different parameters is required to achieve
compatibility with the experimental data. As a particular example, we also
analyze how these corrections modify the tribimaximal mixing pattern and find
that the deviations may be sizable, in particular for . Finally,
we emphasize that due to their large size, the finite corrections to neutrino
masses have to be taken into account if one wants to properly scan the
parameter space of seesaw models.Comment: 24 pages, 11 figure
Evaluating the Quality of Research into a Single Prognostic Biomarker: A Systematic Review and Meta-analysis of 83 Studies of C-Reactive Protein in Stable Coronary Artery Disease
Background
Systematic evaluations of the quality of research on a single prognostic biomarker are rare. We sought to evaluate the quality of prognostic research evidence for the association of C-reactive protein (CRP) with fatal and nonfatal events among patients with stable coronary disease.
Methods and Findings
We searched MEDLINE (1966 to 2009) and EMBASE (1980 to 2009) and selected prospective studies of patients with stable coronary disease, reporting a relative risk for the association of CRP with death and nonfatal cardiovascular events. We included 83 studies, reporting 61,684 patients and 6,485 outcome events. No study reported a prespecified statistical analysis protocol; only two studies reported the time elapsed (in months or years) between initial presentation of symptomatic coronary disease and inclusion in the study. Studies reported a median of seven items (of 17) from the REMARK reporting guidelines, with no evidence of change over time.
The pooled relative risk for the top versus bottom third of CRP distribution was 1.97 (95% confidence interval [CI] 1.78–2.17), with substantial heterogeneity (I2 = 79.5). Only 13 studies adjusted for conventional risk factors (age, sex, smoking, obesity, diabetes, and low-density lipoprotein [LDL] cholesterol) and these had a relative risk of 1.65 (95% CI 1.39–1.96), I2 = 33.7. Studies reported ten different ways of comparing CRP values, with weaker relative risks for those based on continuous measures. Adjusting for publication bias (for which there was strong evidence, Egger's p<0.001) using a validated method reduced the relative risk to 1.19 (95% CI 1.13–1.25). Only two studies reported a measure of discrimination (c-statistic). In 20 studies the detection rate for subsequent events could be calculated and was 31% for a 10% false positive rate, and the calculated pooled c-statistic was 0.61 (0.57–0.66).
Conclusion
Multiple types of reporting bias, and publication bias, make the magnitude of any independent association between CRP and prognosis among patients with stable coronary disease sufficiently uncertain that no clinical practice recommendations can be made. Publication of prespecified statistical analytic protocols and prospective registration of studies, among other measures, might help improve the quality of prognostic biomarker research
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