1,500 research outputs found
Left-right symmetry at LHC and precise 1-loop low energy data
Despite many tests, even the Minimal Manifest Left-Right Symmetric Model
(MLRSM) has never been ultimately confirmed or falsified. LHC gives a new
possibility to test directly the most conservative version of left-right
symmetric models at so far not reachable energy scales. If we take into account
precise limits on the model which come from low energy processes, like the muon
decay, possible LHC signals are strongly limited through the correlations of
parameters among heavy neutrinos, heavy gauge bosons and heavy Higgs particles.
To illustrate the situation in the context of LHC, we consider the "golden"
process . For instance, in a case of degenerate heavy neutrinos
and heavy Higgs masses at 15 TeV (in agreement with FCNC bounds) we get
fb at TeV which is consistent with muon
decay data for a very limited masses in the range (3008 GeV, 3040 GeV).
Without restrictions coming from the muon data, masses would be in the
range (1.0 TeV, 3.5 TeV). Influence of heavy Higgs particles themselves on the
considered LHC process is negligible (the same is true for the light, SM
neutral Higgs scalar analog). In the paper decay modes of the right-handed
heavy gauge bosons and heavy neutrinos are also discussed. Both scenarios with
typical see-saw light-heavy neutrino mixings and the mixings which are
independent of heavy neutrino masses are considered. In the second case heavy
neutrino decays to the heavy charged gauge bosons not necessarily dominate over
decay modes which include only light, SM-like particles.Comment: 16 pages, 10 figs, KL-KS and new ATLAS limits taken into accoun
A rightward shift in the visuospatial attention vector with healthy aging
The study of lateralised visuospatial attention bias in non-clinical samples has revealed a systematic group-level leftward bias (pseudoneglect), possibly as a consequence of right hemisphere dominance for visuospatial attention. Pseudoneglect appears to be modulated by age, with a reduced or even reversed bias typically present in elderly participants. It has been suggested that this shift in bias may arise due to disproportionate aging of the right hemisphere and/or an increase in complementary functional recruitment of the left hemisphere for visuospatial processing. In this study, we report rightward shifts in subjective midpoint judgement relative to healthy young participants whilst elderly participants performed a computerized version of the landmark task (in which they had to judge whether a transection mark appeared closer to the right or left end of a line) on three different line lengths. This manipulation of stimulus properties led to a similar behavioural pattern in both the young and the elderly: a rightward shift in subjective midpoint with decreasing line length, which even resulted in a systematic rightward bias in elderly participants for the shortest line length (1.98° of visual angle). Overall performance precision for the task was lower in the elderly participants regardless of line length, suggesting reduced landmark task discrimination sensitivity with healthy aging. This rightward shift in the attentional vector with healthy aging is likely to result from a reduction in right hemisphere resources/dominance for attentional processing in elderly participants. The significant rightward bias in the elderly for short lines may even suggest a reversal of hemisphere dominance in favour of the left hemisphere/right visual field under specific conditions
Genome-wide association study identifies loci associated with liability to alcohol and drug dependence that is associated with variability in reward-related ventral striatum activity in African- and European-Americans.
Genetic influences on alcohol and drug dependence partially overlap, however, specific loci underlying this overlap remain unclear. We conducted a genome-wide association study (GWAS) of a phenotype representing alcohol or illicit drug dependence (ANYDEP) among 7291 European-Americans (EA; 2927 cases) and 3132 African-Americans (AA: 1315 cases) participating in the family-based Collaborative Study on the Genetics of Alcoholism. ANYDEP was heritable (h 2 in EA = 0.60, AA = 0.37). The AA GWAS identified three regions with genome-wide significant (GWS; P < 5E-08) single nucleotide polymorphisms (SNPs) on chromosomes 3 (rs34066662, rs58801820) and 13 (rs75168521, rs78886294), and an insertion-deletion on chromosome 5 (chr5:141988181). No polymorphisms reached GWS in the EA. One GWS region (chromosome 1: rs1890881) emerged from a trans-ancestral meta-analysis (EA + AA) of ANYDEP, and was attributable to alcohol dependence in both samples. Four genes (AA: CRKL, DZIP3, SBK3; EA: P2RX6) and four sets of genes were significantly enriched within biological pathways for hemostasis and signal transduction. GWS signals did not replicate in two independent samples but there was weak evidence for association between rs1890881 and alcohol intake in the UK Biobank. Among 118 AA and 481 EA individuals from the Duke Neurogenetics Study, rs75168521 and rs1890881 genotypes were associated with variability in reward-related ventral striatum activation. This study identified novel loci for substance dependence and provides preliminary evidence that these variants are also associated with individual differences in neural reward reactivity. Gene discovery efforts in non-European samples with distinct patterns of substance use may lead to the identification of novel ancestry-specific genetic markers of risk
Throat related symptoms and voice: development of an instrument for self assessment of throat-problems
<p>Abstract</p> <p>Background</p> <p>Symptoms from throat (sensation of globus; frequent throat clearing; irritated throat) are common in patients referred to voice clinics and to ENT specialists. The relation to symptoms of voice discomfort is unclear and in some cases patients do not have voice problems at all. Instruments for patients' self-reporting of symptoms, and assessment of handicap, such as the Voice Handicap Index (VHI), are in common use in voice clinics. Symptoms from throat are however only marginally covered. Purpose: To develop and evaluate an instrument that could make the patients' estimation of symptoms from the throat possible. Further to facilitate the consideration of the relation between throat- and voice problems with the Throat subscale together with a Swedish translation of the Voice Handicap Index. Finally to try the VHI with the Throat subscale: the VHI-T, for test-retest reliability and validity.</p> <p>Methods</p> <p>A subscale with 10 throat related items was developed for appliance with the VHI. The VHI was translated to Swedish and retranslated to English. The questionnaire was tried in two phases on a total of 23+144 patients and 12+58 voice healthy controls. The reliability was calculated with Cronbach's alpha, ICC and Pearson's correlation coefficient. The validity was estimated by independent T-test.</p> <p>Results</p> <p>The difference in VHI-T scores between the patients and the voice-healthy controls was significant (<it>p </it>= < 0,01) and there was a good correlation of the test- retest occasions. The reliability testing of the entire questionnaire showed an alpha value of <it>r </it>= 0,90 and that for the Throat subscale separately a value of <it>r </it>= 0,87 which shows a high degree of reliability.</p> <p>Conclusions</p> <p>For the estimation of self-perceived throat and voice problems the scale on throat related problems together with the present Swedish translation of the Voice Handicap Index, (VHI) the VHI-Throat, proves to be a valid and reliable instrument. The throat subscale seems to help revealing a category of symptoms that are common in our patients. These are symptoms that have not earlier been possible to cover with the questionnaires designed for use in the voice clinic.</p
Aspirin use and survival after the diagnosis of breast cancer:a population-based cohort study
Background: Aspirin use has been associated with a reduced cancer incidence and fewer deaths from cancer. This study examined whether women with breast cancer prescribed aspirin postdiagnosis had improved survival.Methods:An observational, population cohort study was undertaken using data linkage of cancer registry, dispensed prescriptions and death records in Tayside, Scotland. All community prescriptions for aspirin in women with breast cancer were extracted and use postdiagnosis for each individual examined using Cox's proportional hazard models. The main outcome measures were all-cause mortality and breast cancer-specific mortality.Results:Four thousand six hundred and twenty-seven patients diagnosed with breast cancer between 1 January 1998 and 31 December 2008 were followed up until 28 February 2010. Median age at diagnosis was 62 (IQR 52-74). One thousand eight hundred and two (39%) deaths were recorded, with 815 (18%) attributed to breast cancer. One thousand and thirty-five (22%) patients were prescribed aspirin postdiagnosis. Such aspirin use was associated with lower risk of all-cause mortality (HR=0.53, 95% CI=0.45-0.63, P<0.001) and breast cancer-specific mortality (HR=0.42, 95% CI=0.31-0.55, P<0.001) after adjusting for age, socioeconomic status, TNM stage, tumour grade, oestrogen receptor status, surgery, radiotherapy, chemotherapy, adjuvant endocrine therapy and aspirin use prediagnosis. Conclusions:Aspirin use postdiagnosis of breast cancer may reduce both all-cause and breast cancer-specific mortality. Further investigation seeking a causal relationship and which subgroups of patients benefit most await ongoing randomised controlled trials.Publisher PDFPeer reviewe
Does chocolate reduce blood pressure? A meta-analysis
BackgroundDark chocolate and flavanol-rich cocoa products have attracted interest as an alternative treatment option for hypertension, a known risk factor for cardiovascular disease. Previous meta-analyses concluded that cocoa-rich foods may reduce blood pressure. Recently, several additional trials have been conducted with conflicting results. Our study summarises current evidence on the effect of flavanol-rich cocoa products on blood pressure in hypertensive and normotensive individuals.MethodsWe searched Medline, Cochrane and international trial registries between 1955 and 2009 for randomised controlled trials investigating the effect of cocoa as food or drink compared with placebo on systolic and diastolic blood pressure (SBP/DBP) for a minimum duration of 2 weeks. We conducted random effects meta-analysis of all studies fitting the inclusion criteria, as well as subgroup analysis by baseline blood pressure (hypertensive/normotensive). Meta-regression analysis explored the association between type of treatment, dosage, duration or baseline blood pressure and blood pressure outcome. Statistical significance was set at P ResultsFifteen trial arms of 13 assessed studies met the inclusion criteria. Pooled meta-analysis of all trials revealed a significant blood pressure-reducing effect of cocoa-chocolate compared with control (mean BP change +/- SE: SBP: -3.2 +/- 1.9 mmHg, P = 0.001; DBP: -2.0 +/- 1.3 mmHg, P = 0.003). However, subgroup meta-analysis was significant only for the hypertensive or prehypertensive subgroups (SBP: -5.0 +/- 3.0 mmHg; P = 0.0009; DBP: -2.7 +/- 2.2 mm Hg, P = 0.01), while BP was not significantly reduced in the normotensive subgroups (SBP: -1.6 +/- 2.3 mmHg, P = 0.17; DBP: -1.3 +/- 1.6 mmHg, P = 0.12). Nine trials used chocolate containing 50% to 70% cocoa compared with white chocolate or other cocoa-free controls, while six trials compared high- with low-flavanol cocoa products. Daily flavanol dosages ranged from 30 mg to 1000 mg in the active treatment groups, and interventions ran for 2 to 18 weeks. Meta-regression analysis found study design and type of control to be borderline significant but possibly indirect predictors for blood pressure outcome.ConclusionOur meta-analysis suggests that dark chocolate is superior to placebo in reducing systolic hypertension or diastolic prehypertension. Flavanol-rich chocolate did not significantly reduce mean blood pressure below 140 mmHg systolic or 80 mmHg diastolic.Karin Ried, Thomas Sullivan, Peter Fakler, Oliver R. Frank and Nigel P. Stock
Determinants of elevated healthcare utilization in patients with COPD
<p>Abstract</p> <p>Background</p> <p>Chronic obstructive pulmonary disease (COPD) imparts a substantial economic burden on western health systems. Our objective was to analyze the determinants of elevated healthcare utilization among patients with COPD in a single-payer health system.</p> <p>Methods</p> <p>Three-hundred eighty-nine adults with COPD were matched 1:3 to controls by age, gender and area of residency. Total healthcare cost 5 years prior recruitment and presence of comorbidities were obtained from a computerized database. Health related quality of life (HRQoL) indices were obtained using validated questionnaires among a subsample of 177 patients.</p> <p>Results</p> <p>Healthcare utilization was 3.4-fold higher among COPD patients compared with controls (p < 0.001). The "most-costly" upper 25% of COPD patients (n = 98) consumed 63% of all costs. Multivariate analysis revealed that independent determinants of being in the "most costly" group were (OR; 95% CI): age-adjusted Charlson Comorbidity Index (1.09; 1.01 - 1.2), history of: myocardial infarct (2.87; 1.5 - 5.5), congestive heart failure (3.52; 1.9 - 6.4), mild liver disease (3.83; 1.3 - 11.2) and diabetes (2.02; 1.1 - 3.6). Bivariate analysis revealed that cost increased as HRQoL declined and severity of airflow obstruction increased but these were not independent determinants in a multivariate analysis.</p> <p>Conclusion</p> <p>Comorbidity burden determines elevated utilization for COPD patients. Decision makers should prioritize scarce health care resources to a better care management of the "most costly" patients.</p
Circumstellar discs: What will be next?
This prospective chapter gives our view on the evolution of the study of
circumstellar discs within the next 20 years from both observational and
theoretical sides. We first present the expected improvements in our knowledge
of protoplanetary discs as for their masses, sizes, chemistry, the presence of
planets as well as the evolutionary processes shaping these discs. We then
explore the older debris disc stage and explain what will be learnt concerning
their birth, the intrinsic links between these discs and planets, the hot dust
and the gas detected around main sequence stars as well as discs around white
dwarfs.Comment: invited review; comments welcome (32 pages
Towards a Processual Microbial Ontology
types: ArticleStandard microbial evolutionary ontology is organized according to a
nested hierarchy of entities at various levels of biological organization. It typically
detects and defines these entities in relation to the most stable aspects of evolutionary
processes, by identifying lineages evolving by a process of vertical inheritance
from an ancestral entity. However, recent advances in microbiology indicate
that such an ontology has important limitations. The various dynamics detected
within microbiological systems reveal that a focus on the most stable entities (or
features of entities) over time inevitably underestimates the extent and nature of
microbial diversity. These dynamics are not the outcome of the process of vertical
descent alone. Other processes, often involving causal interactions between entities
from distinct levels of biological organisation, or operating at different time scales,
are responsible not only for the destabilisation of pre-existing entities, but also for
the emergence and stabilisation of novel entities in the microbial world. In this
article we consider microbial entities as more or less stabilised functional wholes,
and sketch a network-based ontology that can represent a diverse set of processes
including, for example, as well as phylogenetic relations, interactions that stabilise
or destabilise the interacting entities, spatial relations, ecological connections, and
genetic exchanges. We use this pluralistic framework for evaluating (i) the existing
ontological assumptions in evolution (e.g. whether currently recognized entities are
adequate for understanding the causes of change and stabilisation in the microbial
world), and (ii) for identifying hidden ontological kinds, essentially invisible from
within a more limited perspective. We propose to recognize additional classes of
entities that provide new insights into the structure of the microbial world, namely ‘‘processually equivalent’’ entities, ‘‘processually versatile’’ entities, and ‘‘stabilized’’
entities.Economic and Social Research Council, U
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