Lower bounds on the spectra of symmetric matrices with nonnegative entries

AbstractIf we normalize a symmetric n × n matrix with nonnegative entriesso that its largest entry is 1, then its spectrum is bounded below by −n2. The lower bound is achieved in all even dimensions for (and only for) adjacency matrices of complete bipartite graphs with equal parts

The design, instrumentation, and validation of a multiphase shock tube facility

This paper investigates the experimental work in Shock Driven Multiphase Instabilities (SDMI). SDMIs occur when an interface consisting of a particle seeded gas is instantaneously accelerated and begins mixing. SDMIs have similar flow morphologies to the Richtmyer-Meshkov Instability (RMI), however, the driving force inducing this flow is very different. SDMIs occur when there is a relative velocity difference between surrounding gas and the moving particles. This results to a shear at the edges and ultimately leads to rollups that are similar to a RMI. To investigate this phenomena, a shock tube facility was designed, calibrated, and tested to perform experiments. The experimental data was qualitatively compared to simulations performed, as well as to literature of similar experiments. Quantitative data was analyzed using Particle Imaging Velocimetry (PIV) to understand the flow of the instability. The flow morphologies observed in experiments have similar behavior to those performed in simulations. Additionally, the qualitative observations of experiments performed in this lab are also in agreement with experimental literature. Two different effective Atwood numbers are investigated in this study. The first case looks at a gas cylinder interface with an effective Atwood number of -0.01 and a gas Atwood number of -0.02, shocked with a Mach 1.66 shock wave. The observations show a dominating instability resulting in the gas Atwood number. What ends up happening is the smaller particles are pulled into the vortex and the large particles separate and trail behind. The second case looks at the same gas cylinder perturbation but with an effective Atwood number of 0.03 and a gas Atwood number of 0, shocked at Mach 1.66. The higher Atwood number was achieved by modifying the experimental apparatus slightly to deliver a greater number of particles to the shock tube. The experiments observed show that there is agreement with literature and simulations. Certain unusual filaments begin forming at late times, 4.0ms after shock. This was thought to only appear in a pure RMI. In the case of a SDMI, these filaments are a result of colliding particles.Dr. Jacob A. McFarland, Thesis Supervisor.Includes bibliographical references (pages 56-60)

High intensity interval training improves liver and adipose tissue insulin sensitivity

Objective: Endurance exercise training reduces insulin resistance, adipose tissue inflammation and non-alcoholic fatty liver disease (NAFLD), an effect often associated with modest weight loss. Recent studies have indicated that high-intensity interval training (HIIT) lowers blood glucose in individuals with type 2 diabetes independently of weight loss; however, the organs affected and mechanisms mediating the glucose lowering effects are not known. Intense exercise increases phosphorylation and inhibition of acetyl-CoA carboxylase (ACC) by AMP-activated protein kinase (AMPK) in muscle, adipose tissue and liver. AMPK and ACC are key enzymes regulating fatty acid metabolism, liver fat content, adipose tissue inflammation and insulin sensitivity but the importance of this pathway in regulating insulin sensitivity with HIIT is unknown. Methods: In the current study, the effects of 6 weeks of HIIT were examined using obese mice with serine–alanine knock-in mutations on the AMPK phosphorylation sites of ACC1 and ACC2 (AccDKI) or wild-type (WT) controls. Results: HIIT lowered blood glucose and increased exercise capacity, food intake, basal activity levels, carbohydrate oxidation and liver and adipose tissue insulin sensitivity in HFD-fed WT and AccDKI mice. These changes occurred independently of weight loss or reductions in adiposity, inflammation and liver lipid content. Conclusions: These data indicate that HIIT lowers blood glucose levels by improving adipose and liver insulin sensitivity independently of changes in adiposity, adipose tissue inflammation, liver lipid content or AMPK phosphorylation of ACC

Prevalence and determinants of SHS exposure in public and private areas after the 2010 smoke-free legislation in Greece

<div><p>The objective of the present survey was to assess the extent and socio-economic determinants of population exposure to secondhand smoke (SHS) in Greece in 2011. The national household survey Hellas Health IV was conducted in October 2011. SHS exposure was based on self-reported exposure within home, workplace and public places. Thirty-three per cent of the respondents reported living in a smoke-free home. Smokers (<i>p </i><<i> </i>0.001) and single individuals (<i>p </i><<i> </i>0.017) were less likely to prohibit smoking at home. SHS exposure at work, in restaurants and in bars/clubs/cafes was frequently mentioned by 41.6, 84.2 and 90.5%, respectively. SHS exposure in a bar/club/cafe was noted more among single individuals (<i>p </i>=<i> </i>0.004) and those aged 18–34<i> </i>years (<i>p </i>=<i> </i>0.007). Inhabitants of rural areas were more likely to report someone smoking indoors in all the above venues. Public health education and effective enforcement of the nationwide smoke-free legislation are imperative.</p></div

Nursing education and beliefs towards tobacco cessation and control: a cross- sectional national survey (GHPSS) among nursing students in Greece

<p>Abstract</p> <p>Background</p> <p>Within the healthcare system, nurses have the ability to influence their patients' smoking habits through counselling. Therefore, it is of great importance to appropriately train health professionals on smoking cessation strategies with the aim to help them provide advice to their patients. In light of the above, the objective of this study was to assess the association between Greek nursing students' beliefs towards tobacco control/smoking cessation and the professional training received.</p> <p>Methods</p> <p>During February 2009, we conducted a cross sectional national survey among all 3^rdyear nursing students of the two university based nursing departments in Greece (University of Athens, University of the Peloponnese). The Global Health Professional Student Survey (GHPSS) questionnaire was applied and following written informed consent 73% provided a completed questionnaire (n = 192/263 enrolled students).</p> <p>Results</p> <p>Overall, 33% were current active smokers, while 74% reported ever to experiment smoking. In regards to their beliefs towards tobacco control policies, non smokers were more positive in regards to banning smoking in restaurants (94% vs. 61%, p < 0.001), in bars and cafes (82% vs. 34%, p < 0.001), and all public places (93% vs. 51%, p < 0.001) when compared to current smokers. In comparison with students who had not received training on the importance of asking patients about their smoking habits, those that did were more likely to believe that nurses should have a role in smoking cessation and should act as role models for their patients.</p> <p>Conclusions</p> <p>Resources should be invested in improving the quality of undergraduate education in nursing departments in Greece with respect to tobacco control and smoking cessation.</p

Partnership for International Research and Education in Microfluidic Technology with Applications in Point of Care Diagnostic

This poster summarizes the research highlights of a project conducted as part of an National Science Foundation (NSF) partnership for research and education. The objective of this multidisciplinary, international project was to conduct research on microfluidic technology and applications. The project team is comprised of participants from the University of Rhode Island and the Technical University of Braunschweig in Germany. The research focuses on the following four tasks: Task 1 – Discovery of disease biomarkers; Task 2 –Streaming based microfluidic platform for pumping, mixing, separation and detection; Task 3 – Development of rapid, quantitative and sensitive microfluidic fluorescence immunosensors for point-of-care diagnostics; and Task 4 – Microfluidic ocean based applications. The following elements are examined in Task 3: Enzyme-linked Immunosorbent Assay (ELISA) by manipulation of magnetic beads in microfluidic channel network; development of charged coupled device (CCD) contact imaging system for lab-on-a-chip biosensors for detection of disease biomarkers; a portable and hand-held lab-on-a-chip system for detection of disease biomarkers; on-chip valveless sequential sample loading, mixing, and micro-pneumatic valves; and numerical simulation of microfluidics using dissipative particle dynamics

Attitudes towards Electronic Cigarettes Regulation in Indoor Workplaces and Selected Public and Private Places: A Population-Based Cross-Sectional Study

Background: Currently, there is an intensive debate about the regulation of the use of electronic cigarettes (e-cigarettes) in indoor places. The aim of this study was to assess the attitudes toward e-cigarette use in indoor workplaces and selected public and private venues among the general population in Barcelona (Spain) in 2013–2014. Methods: This is a cross-sectional study of a representative sample of the population of Barcelona (n = 736). The field work was conducted between May 2013 and February 2014. We computed the prevalence and the adjusted odds ratios (OR) derived from multivariable logistic regression models. Results: The awareness of e-cigarettes was 82.3%. Forty five percent of respondents did not agree with the use of e-cigarettes in public places and 52.3% in workplaces. The proportion of disapproval of the use of e-cigarettes in indoor places was higher at 71.5% for schools and 65.8% for hospitals and health care centers; while the prevalence of disapproval of e-cigarette use in homes and cars was lower (18.0% and 32.5%, respectively). Respondents who disagreed on the use of e-cigarettes in indoor workplaces were more likely to be older (OR = 1.64 and 1.97 for groups 45–64 and ≧65 years old, respectively), those with a high educational level (OR = 1.60), and never and former smokers (OR = 2.34 and 2.16, respectively). Increased scores in the Fagerström test for cigarette dependence were also related to increased support for their use. Conclusions: Based on this population based study, half of the general population of Barcelona does not support the use of e-cigarettes in indoor workplaces and public places, with the percentage reaching 65% for use in schools, hospitals and health care centers. Consequently, there is good societal support in Spain for the politicians and legislators to promote policies restricting e-cigarettes use in workplaces and public places, including hospitality venues