Nonlinearity in Bacterial Population Dynamics: Proposal for Experiments for the Observation of Abrupt Transitions in Patches

An explicit proposal for experiments leading to abrupt transitions in spatially extended bacterial populations in a Petri dish is presented on the basis of an exact formula obtained through an analytic theory. The theory provides accurately the transition expressions in spite of the fact that the actual solutions, which involve strong nonlinearity, are inaccessible to it. The analytic expressions are verified through numerical solutions of the relevant nonlinear equation. The experimental set-up suggested uses opaque masks in a Petri dish bathed in ultraviolet radiation as in Lin et al., Biophys. J. {\bf 87}, 75 (2004) and Perry, J. R. Soc. Interface {\bf 2}, 379 (2005) but is based on the interplay of two distances the bacteria must traverse, one of them favorable and the other adverse. As a result of this interplay feature, the experiments proposed introduce highly enhanced reliability in interpretation of observations and in the potential for extraction of system parameters.Comment: 5 figure

Essais d'utilisation du bois de certaines espèces forestières pour la fabrication de panneaux de particules (résumé).

International audienc

Richmond City Health District (RCHD), Bon Secours Richmond City Hospital (RCH), and Virginia Commonwealth Universities (VCU) Department of Health Behavior Policy (HBP): Partnering with Community Health Workers (CHW) to Improve Community Health Outcomes and Reduce Emergency Department (ED) Use

Background: Frequent ED users (5%) are sicker, poorer, not satisfied with the health system and cost 20% of total ED charges. Objective: A pilot study of feasibility of partnering with CHW to improve health knowledge and outcomes and reduce ED use in low income community. Methods: RCH ED utilizers were randomized to intervention and control groups. CHW contacted intervention group within 10 days of ED visit, surveyed about access to care, healthy living, and knowledge about chronic disease, and offered education, referrals to insurance and social and economic support. ED utilization and cost were recorded for all patients for 6 months. Preventable ED visits were classified according to Johnston et al1 and high utilizers have 2+ ED visits. Intervention and control characteristics and ED utilizations and cost were described and compared using t-tests, ANOVA, and Chi-square at alpha=0.1. Adjusted analyses were performed using linear and logistic regressions. Results: 91 and 61 randomized to intervention and control with 29 and 23 high utilizers respectively. Drop-in percent of patients with all and preventable ED visits was higher among intervention (12 and 17 percentage points, respectively). 65% of the total ED cost is preventable in the pre-intervention period. That dropped by 17 and 7% in intervention period among the intervention and control groups. The intervention estimated cost savings were $120K. Intervention group had significant improvement in self-reported general health, regular exercise, understanding of health benefits and chronic disease. Conclusions: hospital, academic, and CHW partnership reduces ED utilization and cost and improves health.https://scholarscompass.vcu.edu/gradposters/1116/thumbnail.jp

Aptitude d'espèces spontanées et introduites en Tunisie à la fabrication de panneaux de particules homogènes et trois couches (résumé).

International audienc

Aeropuerto Internacional King Khaled. Riyadh/Arabia Saudita

King Khaled International Airport in Riyadh is the new access to the Saudi Arabia capital and to the heart of the Kingdom. It is the center of the national air transport and it has been planned to attend all the needs of the national and International air traffic, which has a fast growth in Riyadh zone. Its design is adapted to the Islamic traditions and harmonizes with the natural beauty of the desert.El aeropuerto internacional King Khaled de Riyadh es el nuevo acceso aéreo a la capital de Arabia Saudita y al corazón del reino. Es el centro del sistema de transporte aéreo nacional y está proyectado para atender las demandas de tráfico aéreo nacional e internacional, de crecimiento rápido, en la región de Riyadh. Su diseño se adapta a las tradiciones islámicas y armoniza con la belleza natural del desierto

Suboptimal geographic accessibility to comprehensive HIV care in the US: regional and urban–rural differences

Achieving US state and municipal benchmarks to end the HIV epidemic and promote health equity requires access to comprehensive HIV care. However, this care may not be geographically accessible for all people living with HIV (PLHIV). We estimated county-level drive time and suboptimal geographic accessibility to HIV care across the contiguous US, assessing regional and urban–rural differences. We integrated publicly available data from four federal databases to identify and geocode sites providing comprehensive HIV care in 2015, defined as the co-located provision of core HIV medical care and support services. Leveraging street network, US Census and HIV surveillance data (2014), we used geographic analysis to estimate the fastest one-way drive time between the population-weighted county centroid and the nearest site providing HIV care for counties reporting at least five diagnosed HIV cases. We summarized HIV care sites, county-level drive time, population-weighted drive time and suboptimal geographic accessibility to HIV care, by US region and county rurality (2013). Geographic accessibility to HIV care was suboptimal if drive time was \u3e30 min, a common threshold for primary care accessibility in the general US population. Tests of statistical significance were not performed, since the analysis is population-based. We identified 671 HIV care sites across the US, with 95% in urban counties. Nationwide, the median county-level drive time to HIV care is 69 min (interquartile range (IQR) 66 min). The median county-level drive time to HIV care for rural counties (90 min, IQR 61) is over twice that of urban counties (40 min, IQR 48), with the greatest urban–rural differences in the West. Nationally, population-weighted drive time, an approximation of individual-level drive time, is over five times longer in rural counties than in urban counties. Geographic access to HIV care is suboptimal for over 170,000 people diagnosed with HIV (19%), with over half of these individuals from the South and disproportionately the rural South. Nationally, approximately 80,000 (9%) drive over an hour to receive HIV care. Suboptimal geographic accessibility to HIV care is an important structural barrier in the US, particularly for rural residents living with HIV in the South and West. Targeted policies and interventions to address this challenge should become a priority

Elevated Expression of Osteopontin May Be Related to Adipose Tissue Macrophage Accumulation and Liver Steatosis in Morbid Obesity

OBJECTIVE—Osteopontin (OPN) plays an important role in the development of insulin resistance and liver complications in dietary murine models. We aimed to determine the expression pattern of OPN and its receptor CD44 in obese patients and mice according to insulin resistance and liver steatosis

Inner-sphere oxidation of ternary iminodiacetatochromium(III) complexes involving DL-valine and L-arginine as secondary ligands. Isokinetic relationship for the oxidation of ternary iminodiacetato-chromium(III) complexes by periodate

<p>Abstract</p> <p>Background</p> <p>In this paper, the kinetics of oxidation of [Cr^III(HIDA)(Val)(H₂O)₂]⁺and [Cr^III(HIDA)(Arg)(H₂O)₂]⁺(HIDA = iminodiacetic acid, Val = DL-valine and Arg = L-arginine) were studied. The choice of ternary complexes was attributed to two considerations. Firstly, in order to study the effect of the secondary ligands DL-valine and L-arginine on the stability of binary complex [Cr^III(HIDA)(IDA)(H₂O)] towards oxidation. Secondly, transition metal ternary complexes have received particular focus and have been employed in mapping protein surfaces as probes for biological redox centers and in protein capture for both purification and study.</p> <p>Results</p> <p>The results have shown that the reaction is first order with respect to both [IO₄^-] and the complex concentration, and the rate increases over the pH range 2.62 – 3.68 in both cases. The experimental rate law is consistent with a mechanism in which both the deprotonated forms of the complexes [Cr^III(IDA)(Val)(H₂O)₂] and [Cr^III(IDA)(Arg)(H₂O)₂] are significantly more reactive than the conjugate acids. The value of the intramolecular electron transfer rate constant for the oxidation of [Cr^III(HIDA)(Arg)(H₂O)₂]⁺, <it>k</it>₃(1.82 × 10^-3s^-1), is greater than the value of <it>k</it>₁(1.22 × 10^-3s^-1) for the oxidation of [Cr^III(HIDA)(Val)(H₂O)₂]⁺at 45.0°C and <it>I </it>= 0.20 mol dm^-3. It is proposed that electron transfer proceeds through an inner-sphere mechanism <it>via </it>coordination of IO₄^-to chromium(III).</p> <p>Conclusion</p> <p>The oxidation of [Cr^III(HIDA)(Val)(H₂O)₂]⁺and [Cr^III(HIDA)(Arg)(H₂O)₂]⁺by periodate may proceed through an inner-sphere mechanism via two electron transfer giving chromium(VI). The value of the intramolecular electron transfer rate constant for the oxidation of [Cr^III(HIDA)(Arg)(H₂O)₂]⁺, <it>k</it>₃, is greater than the value of <it>k</it>₁for the oxidation of [Cr^III(HIDA)(Val)(H₂O)₂]⁺. A common mechanism for the oxidation of ternary iminodiacetatochromium(III) complexes by periodate is proposed, and this is supported by an excellent isokinetic relationship between ΔH* and ΔS* values for these reactions.</p