General Non-minimal Kinetic coupling to gravity

We study a new model of scalar field with a general non-minimal kinetic coupling to itself and to the curvature, as a source of dark energy, and analyze the cosmological dynamics of this model and the issue of accelerated expansion. A wide variety of scalar fields and potentials giving rise to power-law expansion have been found. The dynamical equation of state is studied for the two cases, without and with free kinetic term . In the first case, a behavior very close to that of the cosmological constant was found. In the second case, a solution was found, which match the current phenomenology of the dark energy. The model shows a rich variety of dynamical scenarios.Comment: 25 pages, 3 figures; figure added, references adde

The torsion cosmology in Kaluza-Klein theory

We have studied the torsion cosmology model in Kaluza-Klein theory. We considered two simple models in which the torsion vectors are $A_{\mu}=(\alpha,0,0,0)$ and $A_{\mu}=a(t)^2(0,\beta,\beta,\beta)$, respectively. For the first model, the accelerating expansion of the Universe can be not explained without dark energy which is similar to that in the standard cosmology. But for the second model, we find that without dark energy the effect of torsion can give rise to the accelerating expansion of the universe and the alleviation of the well-known age problem of the three old objects for appropriated value of the model parameter $\beta$. These outstanding features of the second torsion cosmology model have been supported by the Type Ia supernovae (SNIa) data.Comment: 12 pages, 2 figures. Accepted for publication in JCA

Sex differences in vascular endothelial function and health in humans: Impacts of exercise.

This brief review presents historical evidence for the purported impacts of male and female sex hormones on the vasculature in humans, including effects on macro- and micro-vascular function and health. Impacts of aging on hormonal changes and artery function are considered in the context of the menopause. Physiological data are presented alongside clinical outcomes from large trials, in an attempt to rationalise disparate findings along the bench-to-bedside continuum. Finally, the theoretical likelihood that exercise and hormone treatment may induce synergistic and/or additive vascular adaptations is developed in the context of recent laboratory studies that have compared male and female responses to training. Differences between men and women in terms of the impact of age and cardiorespiratory fitness on endothelial function are addressed. Ultimately, this review highlights the paucity of high quality and compelling evidence regarding the fundamental impact, in humans, of sex differences on arterial function and the moderating impacts of exercise on arterial function, adaptation and health at different ages in either sex. This article is protected by copyright. All rights reserved

Revealing mammalian evolutionary relationships by comparative analysis of gene clusters

Many software tools for comparative analysis of genomic sequence data have been released in recent decades. Despite this, it remains challenging to determine evolutionary relationships in gene clusters due to their complex histories involving duplications, deletions, inversions, and conversions. One concept describing these relationships is orthology. Orthologs derive from a common ancestor by speciation, in contrast to paralogs, which derive from duplication. Discriminating orthologs from paralogs is a necessary step in most multispecies sequence analyses, but doing so accurately is impeded by the occurrence of gene conversion events. We propose a refined method of orthology assignment based on two paradigms for interpreting its definition: by genomic context or by sequence content. X-orthology (based on context) traces orthology resulting from speciation and duplication only, while N-orthology (based on content) includes the influence of conversion events

Project Management in the Oil & Gas Industry - A Bayesian Approach

A reliable ‘Estimate at Completion’ from the early stage of project execution is essential in order to enable efficient and proactive project management. The non-repetitive and uncertain nature of projects and the involvement of multiple stakeholders require the use and integration of multiple informative sources in order to provide accurate forecasts. Moreover, in the Oil&Gas industry projects are characterized by a high level of complexity and financial impact. The paper aims at multiple objectives: introducing the need for the identification and utilization of all the available knowledge in order to improve the forecasting process; developing a Bayesian approach in order to integrate the diverse knowledge sources; exploring the integration of data records and experts’ judgment related to the ongoing project; exploring the integration of data records related to projects completed in the past and to the ongoing project and finally developing a Bayesian model capable of using three different knowledge sources: data records and experts’ judgments related to the ongoing project and data records related to similar projects completed in the past. The model has been tested in a set of large and complex projects in the Oil&Gas industry, in order to forecast the final duration and the final cost. The results show a higher forecasting accuracy of the Bayesian model compared to the traditional Earned Value Management (EVM) methodology

Oxidised cosmic acceleration

We give detailed proofs of several new no-go theorems for constructing flat four-dimensional accelerating universes from warped dimensional reduction. These new theorems improve upon previous ones by weakening the energy conditions, by including time-dependent compactifications, and by treating accelerated expansion that is not precisely de Sitter. We show that de Sitter expansion violates the higher-dimensional null energy condition (NEC) if the compactification manifold M is one-dimensional, if its intrinsic Ricci scalar R vanishes everywhere, or if R and the warp function satisfy a simple limit condition. If expansion is not de Sitter, we establish threshold equation-of-state parameters w below which accelerated expansion must be transient. Below the threshold w there are bounds on the number of e-foldings of expansion. If M is one-dimensional or R everywhere vanishing, exceeding the bound implies the NEC is violated. If R does not vanish everywhere on M, exceeding the bound implies the strong energy condition (SEC) is violated. Observationally, the w thresholds indicate that experiments with finite resolution in w can cleanly discriminate between different models which satisfy or violate the relevant energy conditions.Comment: v2: corrections, references adde

Screening adult patients with a tracheostomy tube for dysphagia: a mixed-methods study of practice in the UK

Background: Patients with tracheostomy tubes are at risk of aspiration and swallowing problems (dysphagia) and because of their medical acuity, complications in this patient population can be severe. It is well recognised that swallow screening in stroke significantly reduces potential complications by allowing early identification and appropriate management of patients at risk (by health professionals), thereby reducing delays in commencing oral intake and preventing unnecessary, costly interventions by speech and language therapists (SLTs). However, there is no standardised swallow screen for the tracheostomised population and there is a paucity of literature regarding either current or best practice in this area. Aims: The aim of this study was therefore to investigate current United Kingdom (UK) practice for swallow (dysphagia) screening for adult patients with tracheostomy tubes and to explore and describe health professionals’ perceptions of their current practice/current systems used. Methods and Procedures: A mixed methods approach was adopted, comprising a semi-structured online questionnaire and recorded follow-up telephone interviews. Participants were SLTs, nurses and physiotherapists working with patients with tracheostomies. Responses were analysed to determine current practice with regard to swallow screening. Thematic analysis of interviews allowed further exploration and clarification of the questionnaire findings. Outcomes and Results: Two-hundred and twenty one questionnaires were completed. Approximately half (45%) of the participants worked in trusts with formal swallow screens, whilst the remainder used a variety of other approaches to identify patients at risk, often relying on informal links with multidisciplinary teams (MDT). In line with current evidence, patients with neurological diagnoses and a tracheostomy were consistently referred directly to speech and language therapy. Only a quarter of questionnaire participants thought their current system was effective at identifying patients at risk of swallowing problems. Eleven questionnaire participants were interviewed. They highlighted the important role of MDT team working here, emphasising both its strengths and weaknesses when working with these patients. Conclusions and Implications: Current practice in the UK for screening patients with a tracheostomy for swallow problems is varied and often sub-optimal. Despite the evidence base for enhancing outcomes, MDT working is still perceived as problematic. A swallow screening tool for use with this population, to enhance MDT working and ensuring that practice fits in line with current evidence, may improve patient safety and care

Petrogenesis of lavas from Detroit Seamount: Geochemical differences between Emperor Chain and Hawaiian volcanoes

The Hawaiian Ridge and Emperor Seamount Chain define a hot spot track that provides an 80 Myr record of Hawaiian magmatism. Detroit Seamount (∼76 to 81 Ma) is one of the oldest Emperor Seamounts. Volcanic rocks forming this seamount have been cored by the Ocean Drilling Program at six locations. Only tholeiitic basalt occurs at Site 884 on the eastern flank and only alkalic basalt, probably postshield lavas, occurs at Sites 883 and 1204 on the summit plateau. However, at Site 1203 the basement core (453 m penetration) includes four thick flows of pahoehoe alkalic basalt underlying ∼300 m of volcaniclastic rocks interbedded with submarine erupted tholeiitic basalt. The geochemical characteristics of these alkalic lavas indicate that phlogopite was important in their petrogenesis; they may represent preshield stage volcanism. The surprising upward transition from subaerial to submarine eruptives implies rapid subsidence of the volcano, which can be explained by the inferred near-ridge axis setting of the seamount at ∼80 Ma. A near-ridge axis setting with thin lithosphere is also consistent with a shallow depth of melt segregation for Detroit Seamount magmas relative to Hawaiian magmas, and the significant role for plagioclase fractionation as the Detroit Seamount magmas evolved in the crust. An important long-term trend along the hot spot track is that 87Sr/86Sr decreases in lavas erupted from ∼40 to 80 Ma. Tholeiitic basalt at Site 884 on Detroit Seamount is the extreme and overlaps with the 87Sr/86Sr-143Nd/144Nd field of Pacific mid-ocean ridge basalts (MORB). Complementary evidence for a depleted component in Detroit Seamount lavas is that relative to Hawaiian basalt, Detroit Seamount lavas have lower abundances of incompatible elements at a given MgO content. These lavas, especially from Sites 883 and 884, trend to extremely unradiogenic Pb isotopic ratios which are unlike MORB erupted at the East Pacific Rise. A component with relatively low 87Sr/86Sr and 206Pb/204Pb is required. Lavas erupted from a spreading center in the Garrett transform fault, 13°28′S on the East Pacific Rise, have this characteristic. A plausible hypothesis is mixing of a plume-related component with a component similar to that expressed in lavas from the Garrett transform fault. However, basaltic glasses from Detroit Seamount also have relatively high Ba/Th, a distinctive characteristic of Hawaiian lavas. We argue that all Detroit Seamount lavas, including those from Site 884, are related to the Hawaiian hot spot. Rejuvenated stage Hawaiian lavas also have high Ba/Th and define a trend to low 87Sr/86Sr and 206Pb/204Pb. We speculate that rejuvenated stage lavas and Detroit Seamount lavas sample a depleted mantle component, intrinsic to the plume, over the past 80 Myr

Biochemical and Structural Evidence in Support of a Coherent Model for the Formation of the Double-Helical Influenza A Virus Ribonucleoprotein

Influenza A virions contain eight ribonucleoproteins (RNPs), each comprised of a negative-strand viral RNA, the viral polymerase, and multiple nucleoproteins (NPs) that coat the viral RNA. NP oligomerization along the viral RNA is mediated largely by a 28-amino-acid tail loop. Influenza viral RNPs, which serve as the templates for viral RNA synthesis in the nuclei of infected cells, are not linear but rather are organized in hairpin-like double-helical structures. Here we present results that strongly support a coherent model for the assembly of the double-helical influenza virus RNP structure. First, we show that NP self-associates much more weakly in the absence of RNA than in its presence, indicating that oligomerization is very limited in the cytoplasm. We also show that once NP has oligomerized, it can dissociate in the absence of bound RNA, but only at a very slow rate, indicating that the NP scaffold remains intact when viral RNA dissociates from NPs to interact with the polymerase during viral RNA synthesis. In addition, we identify a previously unknown NP-NP interface that is likely responsible for organizing the double-helical viral RNP structure. This identification stemmed from our observation that NP lacking the oligomerization tail loop forms monomers and dimers. We determined the crystal structure of this NP dimer, which reveals this new NP-NP interface. Mutation of residues that disrupt this dimer interface does not affect oligomerization of NPs containing the tail loop but does inactivate the ability of NPs containing the tail loop to support viral RNA synthesis in minigenome assays

An integrated clinical program and crowdsourcing strategy for genomic sequencing and Mendelian disease gene discovery.

Despite major progress in defining the genetic basis of Mendelian disorders, the molecular etiology of many cases remains unknown. Patients with these undiagnosed disorders often have complex presentations and require treatment by multiple health care specialists. Here, we describe an integrated clinical diagnostic and research program using whole-exome and whole-genome sequencing (WES/WGS) for Mendelian disease gene discovery. This program employs specific case ascertainment parameters, a WES/WGS computational analysis pipeline that is optimized for Mendelian disease gene discovery with variant callers tuned to specific inheritance modes, an interdisciplinary crowdsourcing strategy for genomic sequence analysis, matchmaking for additional cases, and integration of the findings regarding gene causality with the clinical management plan. The interdisciplinary gene discovery team includes clinical, computational, and experimental biomedical specialists who interact to identify the genetic etiology of the disease, and when so warranted, to devise improved or novel treatments for affected patients. This program effectively integrates the clinical and research missions of an academic medical center and affords both diagnostic and therapeutic options for patients suffering from genetic disease. It may therefore be germane to other academic medical institutions engaged in implementing genomic medicine programs