On the convergence of generalized hill climbing algorithms

AbstractGeneralized hill climbing (GHC) algorithms provide a general local search strategy to address intractable discrete optimization problems. GHC algorithms include as special cases stochastic local search algorithms such as simulated annealing and the noising method, among others. In this paper, a proof of convergence of GHC algorithms is presented, that relaxes the sufficient conditions for the most general convergence proof for stochastic local search algorithms in the literature. Note that classical convergence proofs for stochastic local search algorithms require either that an exponential distribution be used to model the acceptance of candidate solutions along a search trajectory, or that the Markov chain model of the algorithm must be reversible. The proof in this paper removes these limitations, by introducing a new path concept between global and local optima. Convergence is based on the asymptotic behavior of path probabilities between local and global optima. Examples are given to illustrate the convergence conditions. Implications of this result are also discussed

Bird life in semi-arid regions of Chile

Johnson A. W. Bird life in semi-arid regions of Chile . In: La Terre et La Vie, Revue d'Histoire naturelle, tome 12, n°4, 1958. pp. 405-406

The role of IL-6 in skin fibrosis and cutaneous wound healing

The timely resolution of wound healing is critical for restoring the skin as a protective barrier. The switch from a proinflammatory to a reparative microenvironment must be tightly regulated. Interleukin (IL)-6 is a key modulator of the inflammatory and reparative process: it is involved in the differentiation, activation, and proliferation of leukocytes, endothelial cells, keratinocytes, and fibroblasts. This review examines the role of IL-6 in the healing of cutaneous wounds, and how dysregulation of IL-6 signaling can lead to either fibrosis or a failure to heal. The role of an IL-6/TGF-β feedback loop is discussed in the context of fibrogenesis, while IL-6 expression and responses in advanced age, diabetes, and obesity is outlined regarding the development of chronic wounds. Current research on therapies that modulate IL-6 is explored. Here, we consider IL-6′s diverse impact on cutaneous wound healing

10 Year Cardiovascular Risk assessment In university students

Introduction Cardiovascular disease (CVD) causes more than half of all deaths in the European region, and according to WHO, 80% of premature heart disease and stroke is preventable. Healthy lifestyles, such as eating a healthy diet, regular physical activity, and not smoking are the most important preventive measures. Use of CVD risk assessment tools in a young population provides necessary information about risk for CVD which can be used to develop health promotion initiatives for youth. Methods The aim of the study was to compare, BMI, percent body fat (%BF), blood pressure, total cholesterol (TC) and high density lipoprotein cholesterol (HDL C), family history, activity behaviors, and the 10 year risk of having a heart attack between 166 students (21.62±2.59 yrs.) from Utah, USA and 198 students (22.11±2.51 yrs.) from Hungary. The body dimensions were measured according to ISAC methods (Norton et al.1996) the %BF was meas- ured with Omron BF 306 and the 10 year CVD risk was calculated online (http://hp2010.nhlbihin.net/atpiii/calculator). Results According to the results, 92% of the Hungarian students and 100%of the Utah students had an estimated 10 year risk of 1% or less, however 8% of the Hungarians had moderate risk. The high prevalence of low risk was due to the young age of subjects, healthy body composition and non smoking behavior. The Hungarians who had higher risk of heart attack had significantly higher waist hip ratio (WHR), TC, diastolic blood pressure (DBP) and were smokers compared to the Hungarians with low risk. Four percent of the Utah students and 3% of the Hungarian students had positive cardiovascular family history. Based on self-reported levels of physical activity, 19% of Utah women and 14% of Utah men were sedentary compared to 50% of Hungarian women and 46% of Hungarian men. Conclusion Age is one of the primary risk factors for CVD. Young men and women who participated in this study were, for the most part healthy and had a low risk for CVD. Never- theless, our data shows that even young men and women who are sedentary, smoke, and have high WHR, TC, and DBP have increased risk of CVD. Although, symptoms of CVD may not be manifest until later in life, health promotion efforts should also be targeted to young men and women

Ten-year cardiovascular risk assessment in university students

Cardiovascular disease (CVD) is responsible for more than half of all deaths in the European region. The aim of the study was to compare body composition, blood pressure, total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C), family history, activity behaviors, and the 10-year risk of having a heart attack between 166 university students (21.62 - 2.59 yrs) from Utah (USA) and 198 students (22.11 - 2.51 yrs) from Hungary. Ninety-two percent of the Hungarian students and 100% of the Utah students had an estimated 10-year Framingham risk score of 1% or less. The high prevalence of low risk was primarily due to the young age of study participants, healthy body composition and non-smoking behavior. Hungarians who had higher 10-year risk of heart attack had significantly higher waist hip ratio (WHR), TC, diastolic blood pressure (DBP) and were smokers compared to those Hungarians with lower risk. The self-reported physical activity levels between the two groups of students were not different. In conclusion the young men and women who participated in this study were, for the most part healthy; however the smoking habits and the lower physical activity of the Hungarian students likely elevated their risk of CVD.Scopu

A new wrinkle on the enhancon

We generalize the basic enhancon solution of Johnson, Peet and Polchinski by constructing solutions without spherical symmetry. A careful consideration of boundary conditions at the enhancon surface indicates that the interior of the supergravity solution is still flat space in the general case. We provide some explicit analytic solutions where the enhancon locus is a prolate or oblate sphere.Comment: 19 pages, no figure

Effects of nematicides on nematode population densities and crop yield in a turnip-corn-pea cropping system

Nous avons évalué quatre systèmes de conduite de cultures lors d'une étude de 6 ans afin de lutter contre les nematodes dans un système annuel de production de navet-maïs-pois sur des parcelles de sable loameux Tifton naturellement infestées par les Meloidogyne spp. (environ 90 % de M. incognita et 10 % de M. hapla), les Pratylenchus spp. (environ 65 % de P. scribneri, 25 % de P. brachyurus et 10 % de P. zeae), ainsi que par les Paratrichodorus minor et Criconemella ornata. Le navet (Brassica campestris subsp. rapifera) a toléré de faibles quantités de tous les nematodes. Le maïs (Zea mays) 'Pioneer 3369A' a toléré de plus importantes quantités de tous les nematodes que le maïs 'Funks G-4507'. Les densités de population de juvéniles (J2) de Meloidogyne spp. ont été abaissées en deçà de 80 par 150 cm3 de sol par un mélange composé de 98 % de bromure de méthyle et 2 % de chloropicrine et par 20% de methyl isothiocyanate combiné à 80% d'hydrocarbones C3 chlorinés sur le navet et le maïs. Ces populations de nematodes ont augmenté rapidement chez le pois (Vigna unguiculata) 'Pinkeye purplehull' mais ce ne fut pas le cas chez le cultivar Worthmore. Les densités de populations des autres nematodes n'ont pas été affectées par le cultivar de pois ou par le nématicide, en l'occurrence l'ethoprop. Le fenamiphos a été plus efficace que l'ethoprop en abaissant les densités de nematodes. Les augmentations de rendement du système intensif de conduite des cultures se sont échelonnées de 4% à 52 % par rapport aux témoins non traités.Four management systems were evaluated in a six-year study to control nematodes in a turnip-corn-pea annual cropping System on plots of Tifton loamy sand naturally infested with Meloidogyne spp. (about 90 % M. incognita and 10% M. hapla), Pratylenchus spp. (about 65% P. scribneri, 25% P. brachyurus, and 10% P. zeae), Paratrichodorus minor and Criconemella ornata. Turnip (Brassica campestris subsp. rapifera) supported low numbers of all nematodes. 'Pioneer 3369A' corn (Zea mays) supported greater numbers of all nematodes than 'Funks G-4507'. Population densities of Meloidogyne spp. juveniles (J2) were suppressed below 80 per 150 cm3 of soil by 98 % methyl bromide + 2 % chloropicrin and 20 % methyl isothiocyanate + 80 % chlorinated C3 hydrocarbons on turnip and corn, and increased rapidly on 'Pinkeye purplehull', but not on a resistant cultivar, 'Worthmore' pea (Vigna unguiculata). Population densities of other nematodes were not affected by cultivar of pea or the nematicide, ethoprop. Fenamiphos was more effective than ethoprop in suppressing nematode population densities. Increases in crop yield in the intensive management system ranged from 4% to 52% over untreated controls

Editorial: Influence of sleep and recurrent circadian disruption on cardiometabolic health, wellbeing, and safety: from shiftwork to Monday mornings

The modern 24-hour society is contributing to insufficient sleep and a misalignment between behaviors and internal physiology, which have negative health consequences (1). A growing literature points to increased activity during the biological night (e.g., technology use and work hours) that disrupts sleep and circadian rhythms (2, 3). Despite strong evidence for the connection between recurrent sleep and circadian disruption and poor health, exact mechanisms driving these impairments remain unclear. Therefore, this Research Topic sought to highlight research on the mechanisms by which recurrent sleep and circadian disruption impair health and wellbeing

Non-perturbative gauge superpotentials from supergravity

We study U(N) SQCD with N_f <= N flavors of quarks and antiquarks by engineering it with a configuration of fractional D3-branes on a C^3 / Z_2 x Z_2 orbifold. In particular we show how the moduli space of the gauge theory naturally emerges from the classical geometry produced by the D3-branes, and how the non-perturbatively generated superpotential is recovered from geometrical data.Comment: LaTeX, 18 pages, 4 figures; v2: published version with minor changes and an added referenc

Heisenberg Dimer Single Molecule Magnets in a Strong Magnetic Field

We calculate the static and dynamic properties of single crystal, single molecule magnets consisting of equal spin $S=1/2$ or 5/2 dimers. The spins in each dimer interact with each other via the Heisenberg exchange interaction and with the magnetic induction ${\bf B}$ via the Zeeman interaction, and interdimer interactions are negligible. For antiferromagnetic couplings, the static magnetization and specific heat exhibit interesting low temperature $T$ and strong ${\bf B}$ quantum effects. We calculate the frequency spectrum of the Fourier transform of the real part of the time autocorrelation function ${\cal C}_{11}(t)$ for arbitrary $T, {\bf B}$, and compare our results with those obtained for classical spins. We also calculate the inelastic neutron magnetic dynamical structure factor $S({\bf q},\omega)$ at arbitrary $T, {\bf B}$.Comment: 11 pages, 14 figures, submitted to Phys. Rev.