Solar system and equivalence principle constraints on f(R) gravity by chameleon approach

We study constraints on f(R) dark energy models from solar system experiments combined with experiments on the violation of equivalence principle. When the mass of an equivalent scalar field degree of freedom is heavy in a region with high density, a spherically symmetric body has a thin-shell so that an effective coupling of the fifth force is suppressed through a chameleon mechanism. We place experimental bounds on the cosmologically viable models recently proposed in literature which have an asymptotic form f(R)=R-lambda R_c [1-(R_c/R)^{2n}] in the regime R >> R_c. From the solar-system constraints on the post-Newtonian parameter gamma, we derive the bound n>0.5, whereas the constraints from the violations of weak and strong equivalence principles give the bound n>0.9. This allows a possibility to find the deviation from the LambdaCDM cosmological model. For the model f(R)=R-lambda R_c(R/R_c)^p with 0<p<1 the severest constraint is found to be p<10^{-10}, which shows that this model is hardly distinguishable from the LambdaCDM cosmology.Comment: 5 pages, no figures, version to appear in Physical Review

Health in my community: Conducting and evaluating photovoice as a tool to promote environmental health and leadership among Latino/a youth

BackgroundThe PhotoVoice method has shown substantial promise for work with youth in metropolitan areas, yet its potential for use with Latino youth from agricultural areas has not been well documented.ObjectivesThis project was designed to teach environmental health to 15 high school youth while building their individual and community capacity for studying and addressing shared environmental concerns. The project also aimed to test the utility of PhotoVoice with Latino agricultural youth.MethodsFifteen members of the Youth Community Council (YCC), part of a 15-year project with farmworker families in Salinas, CA, took part in a 12-week PhotoVoice project. Their pictures captured the assets and strengths of their community related to environmental health, and were then analyzed by participants. A multi-pronged evaluation was conducted.ResultsYCC members identified concerns such as poor access to affordable, healthy foods and lack of safe physical spaces in which to play, as well as assets, including caring adults and organizations, and open spaces in surrounding areas. Participants presented their findings on radio, television, at local community events, and to key policy makers. The youth also developed two action plans, a successful 5K run/walk and a school recycling project, still in progress. Evaluation results included significant changes in such areas as perceived ability to make presentations, leadership, and self-confidence, as well as challenges including transportation, group dynamics, and gaining access to people in power.ConclusionThe PhotoVoice method shows promise for environmental health education and youth development in farmworker communities

Tracheocutaneous fistula in patients undergoing supracricoid partial laryngectomy: the role of chronic aspiration

The aim of the present retrospective controlled study was to analyse and compare risk factors for tracheocutaneous fistula in patients who received tracheostomy after supracricoid partial laryngectomy with those who received tracheostomy for other causes. We enrolled 39 patients with tracheocutaneous fistulas who were divided into two groups. The first received temporary tracheostomy for supracricoid partial laryngectomies (n = 21), while the control group consisted of patients who received temporary tracheostomy for other causes (n = 18). Risk factors believed to play a role in the pathogenesis of tracheocutaneous fistula were examined including advanced age, cardiopathy, local infections, radiotherapy, elevated body mass index, malnutrition, decannulation time and aspiration grade. The Leipzig and Pearson scale score was significantly higher in the supracricoid partial laryngectomy group (p = 0.006 and 0.031 for univariate and multivariate analyses, respectively). The penetration/aspiration scale score was significantly higher in the supracricoid partial laryngectomy group as determined by univariate analysis (p = 0.014). The decannulation time was significantly lower in the supracricoid partial laryngectomy group (p = 0.004 and 0.0004 for univariate and multivariate analyses, respectively). The number of surgical closures for tracheocutaneous fistula was significantly higher in the supracricoid partial laryngectomy group by univariate analysis (p = 0.027). These results suggest that chronic aspiration and related cough may be important pathogenic factors for tracheocutaneous fistula and could be responsible for the significantly higher rates of closure failure in patients after supracricoid partial laryngectomy

Self-assembly of the simple cubic lattice with an isotropic potential

Conventional wisdom presumes that low-coordinated crystal ground states require directional interactions. Using our recently introduced optimization procedure to achieve self-assembly of targeted structures (Phys. Rev. Lett. 95, 228301 (2005), Phys. Rev. E 73, 011406 (2006)), we present an isotropic pair potential $V(r)$ for a three-dimensional many-particle system whose classical ground state is the low-coordinated simple cubic (SC) lattice. This result is part of an ongoing pursuit by the authors to develop analytical and computational tools to solve statistical-mechanical inverse problems for the purpose of achieving targeted self-assembly. The purpose of these methods is to design interparticle interactions that cause self-assembly of technologically important target structures for applications in photonics, catalysis, separation, sensors and electronics. We also show that standard approximate integral-equation theories of the liquid state that utilize pair correlation function information cannot be used in the reverse mode to predict the correct simple cubic potential. We report in passing optimized isotropic potentials that yield the body-centered cubic and simple hexagonal lattices, which provide other examples of non-close-packed structures that can be assembled using isotropic pair interactions.Comment: 16 pages, 12 figures. Accepted for publication in Physical Review

Tree-ring–based summer mean temperature variations in the Adamello–Presanella Group (Italian Central Alps), 1610–2008 AD

Abstract. Climate records from remote mountain sites and for century-long periods are usually lacking for most continents and also for the European Alps. However, detailed reconstructions of climate parameters for pre-instrumental periods in mountain areas, suffering of glacial retreat caused by recent global warming, are needed in the view of a better comprehension of the environmental dynamics. We present here the first annually-resolved reconstruction of summer (JJA) mean temperature for the Adamello–Presanella Group (Central European Alps), one of the most glaciated mountain groups of the Italian Central Alps. The reconstruction has been based on four larch tree-ring width chronologies derived from living trees sampled in four valleys surrounding the Group. The reconstruction spans from 1610 to 2008 and the statistical verification of the reconstruction demonstrates the positive skill of the tree-ring dataset in tracking summer temperature variability also in the recent period

Dendroclimatic relevance of “Bosco Antico”, the most ancient living European larch wood in the southern Rhaetian Alps (Italy).

The ongoing increase in the global mean temperature at an unprecedented recorded rate is well documented. Nevertheless, knowledge of past climate variations is fundamental for a better understanding of ongoing climate change. This need is crucial in high mountain areas, where the effects of global warming are amplified and induce an accelerated glacial retreat. Thus, the use of climatic proxies such as tree-ring width offers tools to better understand the environmental dynamics in remote, sensitive sites. Here, we present the “Bosco Antico” site chronology, a six-century long dataset from the most ancient living stand in the Val di Sole area (southern Rhaetian Alps, Italy), and its relationship with summer mean temperatures. The analyses were performed on earlywood and latewood separately, as well as on tree-ring widths using static and moving correlations. The results showed that tree-rings and earlywood width are linked with June temperatures, whereas latewood width is mainly driven by July temperatures. All the analysed series were greatly influenced by June to July and June to August temperatures. Finally, a mean summer latewood-based temperature reconstruction since 1525 is proposed. It highlighted that during the last six hundred years, the summer temperatures span between -2.3 to +1.9 °C compared to the 1960–90 mean temperature (between 6.2 and 10.4 °C at the stand elevation). The coolest phase is recorded in the 1810s-20s underlining the strongest pulse of the Little Ice Age; other phases of negative anomalies are recorded in the first half of the 17th century, around 1700, and 1900 and during the 1970s. Our results add an important dataset for a specific climatic area, providing new information that will contribute to a better understanding of the climate dynamics for the study site as well as on a larger scale

Cooperative Origin of Low-Density Domains in Liquid Water

We study the size of clusters formed by water molecules possessing large enough tetrahedrality with respect to their nearest neighbors. Using Monte Carlo simulation of the SPC/E model of water, together with a geometric analysis based on Voronoi tessellation, we find that regions of lower density than the bulk are formed by accretion of molecules into clusters exceeding a minimum size. Clusters are predominantly linear objects and become less compact as they grow until they reach a size beyond which further accretion is not accompanied by a density decrease. The results suggest that the formation of "ice-like" regions in liquid water is cooperative.Comment: 16 pages, 6 figure

Value-based health-care principles in health-care organizations

Purpose: This study aims to analyze the value-based health-care model in defining a strategy to guide the evolution of health-care organizations toward a value-oriented model. To improve the quality of care by ensuring economic sustainability, it is necessary to redefine the concept of competition in healthcare and align it with the concept of maximizing value for patients. Design/methodology/approach: Performance measurement is a crucial aspect of the analysis of health-care organizations. Porter developed an effective analytical technique and presented the measurement of health-care outcomes based on health conditions, the efficiency of health-care organizations and the type of service provided. Findings: Clinical outcomes and data on the costs of care of each patient are essential to evaluate improvement in treatment value over time. Engaging in the evaluation of what happens to patients in their course of care enables the expansion of the measurement of outcomes because it measures all the health services related to it. Originality/value: Building a health-care system based on the value and continuous improvement of care and services provided is a goal shared by many countries and international organizations. Today, the analysis of outcomes is important for making informed decisions, directing and planning clinical and organizational changes by improving the quality of care and services