1,067 research outputs found
Experimental Investigation of a Supersonic Boundary Layer Including Favorable Pressure Gradient Effects
This study used advanced laser Doppler velocimetry techniques to measure the turbulence intensities and Reynolds shear stresses in Mach 2.8 turbulent flat plate and Mach 2.9 favorable pressure gradient (FPG) boundary layers. The FPG was generated using a convex curved wall and had a strength of ß = 0.1, where ß is Clauser\u27s equilibrium parameter. The maximum magnitude of the \u27extra\u27 strain rates normalized by the main strain rates was 0.1, which meant the FPG was considered to be a strong pressure gradient. The fiat plate results indicated that the LDV procedures used in this experiment prevented angular biasing of the velocity measurements reported in the literature. Analysis of the LDV system settings also showed that this biasing, which has been attributed in the past to the angular alignment of the lasers, may have actually been caused, at least in part, by the choice of record interval used during data collection. Measurements in the FPG test section demonstrated that the stabilizing effect of the FPG reduced the turbulence intensities below the location y/δ ≤ 0.5. Near the wall, the u-turbulence intensity was found to be reduced to 70% of the flat-plate value. In addition, the FPG reduced the magnitude of the incompressible Reynolds shear stresses (-pu\u27v\u27) by approximately 75%. Comparison of the LDV data to hot-wire data collected in the same facilities showed that the assumption of p\u27 = 0, used in the reduction of the hot-wire data, was valid in the fiat plate region but not the FPG region. The increase in the magnitude of p\u27 was likely due to the streamline curvature associated with the generation of the FPG and the resulting pressure difference across the boundary layer
Education-only versus a multifaceted intervention for improving assessment of rehabilitation needs after stroke: a cluster randomised trial
In 2011, more than half of the patients with stroke in Australian hospitals were not assessed for the need for rehabilitation. Further, there were no recommended criteria to guide rehabilitation assessment decisions. Subsequently, a decision-making tool called the Assessment for Rehabilitation Tool (ART) was developed. The ART was designed to assist Australian hospital clinicians to identify the rehabilitation needs of patients with stroke using evidence-based criteria. The ART was released and made freely available for use in 2012. This study evaluated the effectiveness of an education-only intervention (1 onsite education session and distribution of the ART) and a multifaceted intervention (2 or more onsite education sessions, distribution of the ART, audit and feedback, barrier identification, site-specific strategy development, promotion of interdisciplinary teamwork, opinion leaders and reminders) for improving assessments of rehabilitation needs after stroke. Ten hospitals in 2 states of Australia were randomly assigned to an education-only or a multifaceted intervention. Medical records were audited by assessors blinded to group allocation before and after the implementation period. Difference in the proportion of patients assessed for rehabilitation before and after the intervention was analysed using mixed-effects logistic regression analysis, with time period as the dependent variable, an interaction between intervention type and time included to test for differences between the interventions, and hospital included as the random effect to account for patient clustering. Data from 586 patients (284 pre-intervention; 302 post-intervention; age 76 years, 59 % male) showed that the multifaceted intervention was not more effective than education-only in improving the proportion of patients whose rehabilitation needs were assessed (reference category education-only; odds ratio 1.29, 95 % confidence interval 0.63-2.67, p = 0.483). Post-intervention, the odds of a patient's rehabilitation needs being assessed was 3.69 times greater than pre-intervention (95 % confidence interval 2.57-5.30, p < 0.001). Evidence-based criteria were not consistently used when patients were deemed to have no rehabilitation needs. A multifaceted intervention was not more effective than education-only in improving the assessment of rehabilitation needs of patients with stroke. Further interventions are required to ensure that all patients are assessed for the need for rehabilitation using evidence-based criteria. ANZCTR (Australian New Zealand Clinical Trials Registry), ACTRN12616000340437.Elizabeth A. Lynch, Dominique A. Cadilhac, Julie A. Luker and Susan L. Hillie
Finding Your Literature Match -- A Recommender System
The universe of potentially interesting, searchable literature is expanding
continuously. Besides the normal expansion, there is an additional influx of
literature because of interdisciplinary boundaries becoming more and more
diffuse. Hence, the need for accurate, efficient and intelligent search tools
is bigger than ever. Even with a sophisticated search engine, looking for
information can still result in overwhelming results. An overload of
information has the intrinsic danger of scaring visitors away, and any
organization, for-profit or not-for-profit, in the business of providing
scholarly information wants to capture and keep the attention of its target
audience. Publishers and search engine engineers alike will benefit from a
service that is able to provide visitors with recommendations that closely meet
their interests. Providing visitors with special deals, new options and
highlights may be interesting to a certain degree, but what makes more sense
(especially from a commercial point of view) than to let visitors do most of
the work by the mere action of making choices? Hiring psychics is not an
option, so a technological solution is needed to recommend items that a visitor
is likely to be looking for. In this presentation we will introduce such a
solution and argue that it is practically feasible to incorporate this approach
into a useful addition to any information retrieval system with enough usage.Comment: Contribution to the proceedings of the colloquium Future Professional
Communication in Astronomy II, 13-14 April 2010, Cambridge, Massachusetts. 11
pages, 4 figures
Supporting the learning of deaf students in higher education: a case study at Sheffield Hallam University
This article is an examination of the issues surrounding support for the learning of deaf students in higher education (HE). There are an increasing number of deaf students attending HE institutes, and as such provision of support mechanisms for these students is not only necessary but essential. Deaf students are similar to their hearing peers, in that they will approach their learning and require differing levels of support dependant upon the individual. They will, however, require a different kind of support, which can be technical or human resource based. This article examines the issues that surround supporting deaf students in HE with use of a case study of provision at Sheffield Hallam University (SHU), during the academic year 1994-95. It is evident that by considering the needs of deaf students and making changes to our teaching practices that all students can benefit
A Comprehensive Analysis of CXCL12 Isoforms in Breast Cancer1,2
AbstractCXCL12-CXCR4-CXCR7 signaling promotes tumor growth and metastasis in breast cancer. Alternative splicing of CXCL12 produces isoforms with distinct structural and biochemical properties, but little is known about isoform-specific differences in breast cancer subtypes and patient outcomes. We investigated global expression profiles of the six CXCL12 isoforms, CXCR4, and CXCR7 in The Cancer Genome Atlas breast cancer cohort using next-generation RNA sequencing in 948 breast cancer and benign samples and seven breast cancer cell lines. We compared expression levels with several clinical parameters, as well as metastasis, recurrence, and overall survival (OS). CXCL12-α, -β, and -γ are highly co-expressed, with low expression correlating with more aggressive subtypes, higher stage disease, and worse clinical outcomes. CXCL12-δ did not correlate with other isoforms but was prognostic for OS and showed the same trend for metastasis and recurrence-free survival. Effects of CXCL12-δ remained independently prognostic when taking into account expression of CXCL12, CXCR4, and CXCR7. These results were also reflected when comparing CXCL12-α, -β, and -γ in breast cancer cell lines. We summarized expression of all CXCL12 isoforms in an important chemokine signaling pathway in breast cancer in a large clinical cohort and common breast cancer cell lines, establishing differences among isoforms in multiple clinical, pathologic, and molecular subgroups. We identified for the first time the clinical importance of a previously unstudied isoform, CXCL12-δ
Corneal Replication Is an Interferon Response-Independent Bottleneck for Virulence of Herpes Simplex Virus 1 in the Absence of Virion Host Shutoff
Herpes simplex viruses lacking the virion host shutoff function (Δvhs) are avirulent and hypersensitive to type I and type II interferon (IFN). In this study, we demonstrate that even in the absence of IFN responses in AG129 (IFN-αβγR−/−) mice, Δvhs remains highly attenuated via corneal infection but is fully virulent via intracranial infection. The data demonstrate that the interferon-independent inherent replication defect of Δvhs has a significant impact upon peripheral replication and neuroinvasion
Integrating inverse reinforcement learning into data-driven mechanistic computational models: a novel paradigm to decode cancer cell heterogeneity
Cellular heterogeneity is a ubiquitous aspect of biology and a major obstacle to successful cancer treatment. Several techniques have emerged to quantify heterogeneity in live cells along axes including cellular migration, morphology, growth, and signaling. Crucially, these studies reveal that cellular heterogeneity is not a result of randomness or a failure in cellular control systems, but instead is a predictable aspect of multicellular systems. We hypothesize that individual cells in complex tissues can behave as reward-maximizing agents and that differences in reward perception can explain heterogeneity. In this perspective, we introduce inverse reinforcement learning as a novel approach for analyzing cellular heterogeneity. We briefly detail experimental approaches for measuring cellular heterogeneity over time and how these experiments can generate datasets consisting of cellular states and actions. Next, we show how inverse reinforcement learning can be applied to these datasets to infer how individual cells choose different actions based on heterogeneous states. Finally, we introduce potential applications of inverse reinforcement learning to three cell biology problems. Overall, we expect inverse reinforcement learning to reveal why cells behave heterogeneously and enable identification of novel treatments based on this new understanding
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Core needs and diverse opportunity: A survey of academic clinical lecturers and the effects of the COVID-19 pandemic.
During a clinical lecturer role, parallel clinical and academic training is undertaken. The anticipation is that a lectureship represents an exciting and expansive time. However, a national crisis has been declared at the clinical lecturer level with a leaky pipeline of clinical academics resulting in dwindling numbers. Clinical lecturers are infrequently represented as a group partly due to their distributed nature and diverse job plans. We conducted a survey of clinical lecturers in the UK. Responses (n = 107) revealed a motivated but divided workforce. A content analysis revealed core elements that sculpt an individual's success or failure, but these were variably present. COVID-19 had a negative effect on many with various strategies reported to try and reset academic trajectories. Feelings of isolation and anxiety about a viable future in academia were significant findings. This echoes calls for a greater number of secure longer-term grants to ensure that clinical academics and their skills are retained within the research workforce. A continued effort to analytically appraise whether supportive elements are in place for all lecturers will help focus initiatives to foster excellence in clinical academic training for everyone
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