Attractive Interactions Between Rod-like Polyelectrolytes: Polarization, Crystallization, and Packing

We study the attractive interactions between rod-like charged polymers in solution that appear in the presence of multi-valence counterions. The counterions condensed to the rods exhibit both a strong transversal polarization and a longitudinal crystalline arrangement. At short distances between the rods, the fraction of condensed counterions increases, and the majority of these occupy the region between the rods, where they minimize their repulsive interactions by arranging themselves into packing structures. The attractive interaction is strongest for multivalent counterions. Our model takes into account the hard-core volume of the condensed counterions and their angular distribution around the rods. The hard core constraint strongly suppresses longitudinal charge fluctuations.Comment: 4 figures, uses revtex, psfig and epsf. The new version contains a different introduction, and the bibliography has been expande

A Modified Random Phase Approximation of Polyelectrolyte Solutions

We compute the phase diagram of salt-free polyelectrolyte solutions using a modified Debye-Huckel Approach. We introduce the chain connectivity via the Random Phase Approximation with two important modifications. We modify the electrostatic potential at short distances to include a bound on the electrostatic attractions at the distance of closest approach between charges. This modification is shown to act as a hard core in the phase diagram of electrolyte solutions. We also introduce a cut-off on the integration of the modes of wave length smaller than the size over which the chains are strongly perturbed by the electrostatic interactions. This cut-off is shown to be essential to predict physical phase diagram in long chain solutions

Addressing the disparities in dementia risk, early detection and care in Latino populations: Highlights from the Second Latinos and Alzheimer's Symposium

The Alzheimer's Association hosted the second Latinos & Alzheimer's Symposium in May 2021. Due to the COVID-19 pandemic, the meeting was held online over 2 days, with virtual presentations, discussions, mentoring sessions, and posters. The Latino population in the United States is projected to have the steepest increase in Alzheimer's disease (AD) in the next 40 years, compared to other ethnic groups. Latinos have increased risk for AD and other dementias, limited access to quality care, and are severely underrepresented in AD and dementia research and clinical trials. The symposium highlighted developments in AD research with Latino populations, including advances in AD biomarkers, and novel cognitive assessments for Spanish-speaking populations, as well as the need to effectively recruit and retain Latinos in clinical research, and how best to deliver health-care services and to aid caregivers of Latinos living with AD

Competition and habitat quality influence age and sex distribution in wintering rusty blackbirds.

Bird habitat quality is often inferred from species abundance measures during the breeding and non-breeding season and used for conservation management decisions. However, during the non-breeding season age and sex classes often occupy different habitats which suggest a need for more habitat-specific data. Rusty Blackbird (Euphagus carolinus) is a forested wetland specialist wintering in bottomland hardwood forests in the south-eastern U. S. and belongs to the most steeply declining songbirds in the U.S. Little information is available to support priority birds such as the Rusty Blackbird wintering in this threatened habitat. We assessed age and sex distribution and body condition of Rusty Blackbirds among the three major habitats used by this species in the Lower Mississippi Alluvial Valley and also measured food availability. Overall, pecan groves had the highest biomass mainly driven by the amount of nuts. Invertebrate biomass was highest in forests but contributed only a small percentage to overall biomass. Age and sex classes were unevenly distributed among habitats with adult males primarily occupying pecan groves containing the highest nut biomass, females being found in forests which had the lowest nut biomass and young males primarily staying in forest fragments along creeks which had intermediate nut biomass. Males were in better body condition than females and were in slightly better condition in pecan groves. The results suggest that adult males occupy the highest quality habitat and may competitively exclude the other age and sex classes

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

DESARROLLO DE UN SISTEMA ECONÓMICO PARA MONITOREAR RADÓN EN INSTALACIONES INDUSTRIALES Y DE VIVIENDA

222Rn is formed by the decay of 226Ra , then decays into 218Po and 214Po . Po ions electrostatically produced can be collected using a camera with a polarized high voltage then decays 218Po 214Pb particles emitting at 6.003 keV and thereafter decays 214Po 210Pb emitting particles at 7.687 keV. By measuring the concentration of these alpha particles in the camera can determine the concentration of radon in the air in an indirect way . The prototype has been developed using a measuring chamber 2 L stainless steel of a S3204 -09 PIN diode ( Hamamatsu ) bare body as alpha-particle detector . The camera and diode are polarized with a source of high voltage ( +500 V ) to collect ions and detect Po alpha particles that are then produced in the decay chain . Operations and digital functions are implemented on a PIC18F4550 microcontroller and the device has an internal USB module communication for transferring data to a PC. The configuration of basic parameters is done through a laptop via USB port. Calibration was performed using a system Alfaguard sales team and an area where uranium has been buried for a source of radon , measurements were made at different points with different concentrations of radon. It has been possible to monitor the radon ventilated offices closed and is observed as the variation of radon over several days .El 222Rn se forma por la desintegración del 226Ra, y luego se desintegra en 218Po y 214Po. Los iones de Po producidos se pueden colectar electrostáticamente usando una cámara polarizada con una fuente de alta tensión, luego el 218Po decae a 214Pb emitiendo particulas a de 6.003 keV y posteriormente el 214Po decae a 210Pb emitiendo partículas a de 7.687 keV. Al medir la concentración de estas partículas alfas en la cámara se puede determinar la concentración del radón en el aire de una forma indirecta. El prototipo que se ha desarrollando utiliza una cámara de medida de acero inoxidable de 2 L con un diodo PIN S3204-09 (Hamamatsu) de cuerpo desnudo como detector de partículas alfa. La cámara y el diodo están polarizados con una fuente de alta tensión (+500 V) para colectar los iones de Po y detectar las partículas alfas que se producen luego en la cadena de decaimiento. Las operaciones y funciones digitales son implementadas sobre un microcontrolador PIC18F4550 y este dispositivo cuenta con un módulo de comunicación USB interno para realizar la transferencia de los datos a una PC. La configuración de los parámetros básicos de operación se realiza a través de una laptop por medio del puerto USB. Se ha realizado la calibración del sistema usando un equipo comercial Alfaguard y una zona donde se ha enterrado uranio para tener una fuente de radón, se han realizado las medidas en diferentes puntos con diferentes concentraciones de radón. Se ha logrado monitorear el radón en oficinas cerradas y ventiladas observándose como es la variación de radón a lo largo de varios día

[Impacto en la salud mental de estudiantes universitarios y sus padres en los inicios de la pandemia COVID-19]

Se realizó una investigación transversal analítica, multicéntrica, en donde se encuestó a padres e hijos con la escala DASS-21, haciendo los cruces y ajustando por algunas otras variables. De los 1832 estudiantes y 1832 jefes de familia encuestados, según el tener una presentación severa, el 35% de los padres tenían estrés (p<0,001), el 44% tenían ansiedad (p<0,001) y el 25% tenían depresión (p<0,001), esto si sus hijos tenían entrés, ansiedad o depresión severos; respectivamente. Si el jefe de familia presentó depresión moderada/severa se asoció con que sus hijos tengan depresión o ansiedad; el que el padre de familia padezca de ansiedad moderada/severa se asoció con el hecho de que los hijos tengan también depresión o ansiedad y el que los jefes de familia presenten cuadros de estrés moderado/severo tuvo asociación con que los hijos tuviesen ansiedad y estrés (hasta aquí todos los valores p<0,002); así como, que los jefes del hogar fuesen mujeres (p=0,034). Se encontró una evidente asociación de los problemas de la salud mental de los hijos con los de sus padres, esto debe alertar de que existen hogares completos con problemas mentales, y que guardan relación del padecimiento de las patologías

Family mediators of the relation between acculturation and adolescent mental health.

This study of 175 Mexican-origin families examined a mediational model linking the linguistic acculturation of mothers and adolescents with a wide array of family mediators and adolescent mental health outcomes. Family linguistic acculturation, a latent construct based on maternal and adolescent acculturation, was positively related to increased family and interparental conflict but was not related to maternal parenting practices. Family conflict mediated the link between acculturation and two adolescent outcomes, conduct problems and depressive symptoms. Family acculturation showed a complex pattern of positive, indirect (mediated) and negative, direct effects on adolescent depressive symptoms. Findings are discussed in relation to traditional cultural values of Mexican heritage families and prevailing theories about why more acculturated Mexican-origin youth are at increased risk for problem behaviors