Electrokinetic and hydrodynamic properties of charged-particles systems: From small electrolyte ions to large colloids

Dynamic processes in dispersions of charged spherical particles are of importance both in fundamental science, and in technical and bio-medical applications. There exists a large variety of charged-particles systems, ranging from nanometer-sized electrolyte ions to micron-sized charge-stabilized colloids. We review recent advances in theoretical methods for the calculation of linear transport coefficients in concentrated particulate systems, with the focus on hydrodynamic interactions and electrokinetic effects. Considered transport properties are the dispersion viscosity, self- and collective diffusion coefficients, sedimentation coefficients, and electrophoretic mobilities and conductivities of ionic particle species in an external electric field. Advances by our group are also discussed, including a novel mode-coupling-theory method for conduction-diffusion and viscoelastic properties of strong electrolyte solutions. Furthermore, results are presented for dispersions of solvent-permeable particles, and particles with non-zero hydrodynamic surface slip. The concentration-dependent swelling of ionic microgels is discussed, as well as a far-reaching dynamic scaling behavior relating colloidal long- to short-time dynamics

The use of audio-relaxation does not affect the basketball free throw of young college students

INTRODUCTION: As the pressure of competition increase, the athlete will begin to doubt or feel insecure, generating muscular tension and difficulty in the movement. In sports, especially basketball, relaxation is a key part of fine-skills coordination. For this reason, it is determinate that audio-relaxation can become of paramount importance in sport. PURPOSE: To determine if the basketball free throw is influenced by audio-relaxation in a group of physically active college students. METHODS: Eight physically active, apparently healthy college students (­4 male and 4 female) volunteered to participate in this study. The students height was 168.3 ± 8.7cm (range, 155-181cm), mass 76.8±19.5kg (range, 51.5-115.0kg) and age 21.5 ± 1.3y.o (range, 20-24y.o). Subjects attended the study on two occasions, with seven days interval between sessions. Randomly, the first session consisted of listening to audio-relaxation for 16 minutes. In the second session (session control), audio-relaxation was not played while the subjects waited for 16 minutes. The application of the treatment was performed in a room isolated from noise and light, just as it happened for the control condition, in which there was no treatment. In each session, the volunteers were evaluated before and after treatment, performing 20 free throws, 10 shots were performed at their own rhythm and the other 10 under pressure (at the sound of the whistle). RESULTS: According to the normal distribution in the values (p=0.200), a two-way repeated measures ANOVA was performed, in which it was found that there is no interaction between listening and not listening to audio-relaxation in the execution of ten free throws at their own rhythm and ten under pressure (p=0.510). CONCLUSION: Listening audio-relaxation does not significantly influence the effectiveness of the basketball free throws, it means that the people will not get improve their performance if use audio-relaxation technique

The shallow-water fish assemblage of Isla del Coco National Park, Costa Rica: structure and patterns in an isolated, predator-dominated ecosystem

18 páginas, 7 figuras, 5 tablas[EN]Fishes at Isla del Coco National Park, Costa Rica, were surveyed as part of a larger scientific expedition to the area in September 2009. The average total biomass of nearshore fishes was 7.8 tonnes per ha, among the largest observed in the tropics, with apex predators such as sharks, jacks, and groupers accounting for nearly 40% of the total biomass. The abundance of reef and pelagic sharks, particularly large aggregations of threatened species such as the scalloped hammerhead shark (up to 42 hammerheads ha-1) and large schools of jacks and snappers show the capacity for high biomass in unfished ecosystems in the Eastern Tropical Pacific. However, the abundance of hammerhead and reef whitetip sharks appears to have been declining since the late 1990s, and likely causes may include increasing fishing pressure on sharks in the region and illegal fishing inside the Park. One Galapagos shark tagged on September 20, 2009 in the Isla del Coco National Park moved 255km southeast towards Malpelo Island in Colombia, when it stopped transmitting. These results contribute to the evidence that sharks conduct large-scale movements between marine protected areas (Isla del Coco, Malpelo, Galápagos) in the Eastern tropical Pacific and emphasize the need for regional-scale management. More than half of the species and 90% of the individuals observed were endemic to the tropical eastern Pacific. These high biomass and endemicity values highlight the uniqueness of the fish assemblage at Isla del Coco and its importance as a global biodiversity hotspot.[ES]La biomasa promedio de peces costeros en el Parque Nacional Isla del Coco en septiembre de 2010 fue de 7,8 toneladas por hectárea, entre las más elevadas halladas jamás en zonas tropicales. Los grandes depredadores representaron el 40% de la biomasa total. La abundancia de tiburones costeros y pelágicos, particularmente las enormes agregaciones de tiburón martillo (hasta 42 individuos por hectárea) y los extensos bancos de carángidos y lutjánidos, muestran la capacidad que tienen los ecosistemas marinos no pescados para albergar elevadas biomasas de peces, y hacen de la Isla del Coco un lugar único en el mundo. No obstante, la abundancia de tiburones parece estar decreciendo desde 1999, probablemente a causa de la creciente presión pesquera en la región y la pesca ilegal en el interior del Parque. Un tiburón de Galápagos marcado se dirigió 255km en dirección a la Isla de Malpelo, Colombia. Estos resultados sugieren que los tiburones realizan importantes movimientos entre áreas marinas protegidas (Isla del Coco, Malpelo, Galápagos) en el Pacífico Tropical Oriental y remarcan la necesidad de una gestión regional de estos animales. Más del 50% de las especies y el 90% de individuos observados en los contajes eran endémicos del Pacífico Tropical Oriental.Peer reviewe

Estimating the burden of COVID-19 on mortality, life expectancy and lifespan inequality in England and Wales : a population-level study

Objective: To determine the impact of the COVID-19 pandemic on mortality, life expectancy and lifespan inequality in the first half of 2020 (from week 1 to week 26 starting June 22) in England and Wales. Design: Demographic analysis of all-cause mortality from week 1 through week 26 of 2020 using publicly available death registration data from the Office for National Statistics. Setting and population: England and Wales population by age and sex in 2020. Main outcome measure: Age and sex-specific excess mortality risk and deaths above a baseline adjusted for seasonality in the first half of 2020. We additionally provide estimates of life expectancy at birth and lifespan inequality defined as the standard deviation in age at death. Results: We estimate that there have been 53,937 (95% Prediction Interval: 53,092, 54,746) excess deaths in the first half of 2020, 54% of which occurred in men. Excess deaths increased sharply with age and men experienced elevated risks of death in all age groups. Life expectancy at birth dropped 1.7 and 1.9 years for females and males relative to the 2019 levels, respectively. Lifespan inequality also fell over the same period. Conclusions: Quantifying excess deaths and their impact on life expectancy at birth provides a more comprehensive picture of the full COVID-19 burden on mortality. Whether mortality will return to - or even fall below - the baseline level remains to be seen as the pandemic continues to unfold and diverse interventions are put in place

Factors Influencing the Concentration of Fecal Coliforms in Oysters in the River Blackwater Estuary, UK

Contamination of water systems can not only entail high risks to human health but can also result in economic losses due to closure of beaches and shellfish harvesting areas. Understanding the origin of fecal pollution at locations where shellfish are grown is essential in assessing associated health risks—as well as the determining actions necessary to remedy the problem. The aim of this work is to identify the species-specific source(s) of fecal contamination impacting waters overlying the shellfisheries in the Blackwater Estuary, East Anglia, UK. Over a twelve-month period, water samples were taken from above the oysters and from a variety of upstream points considered to be likely sources of fecal microorganism, together with oyster samples, and the number of fecal streptococci and E. coli were determined. Transition from low to high tide significantly decreased the concentration of fecal streptococci in waters overlying the oyster beds, indicative of a freshwater input of fecal pollution in oyster bed waters. In 12 months, the number of E. coli remained constant throughout, while fecal streptococci numbers were generally higher in the winter months. Analyses of upstream samples identified a sewage outfall to be the main source of E. coli to the oyster beds, with additional fecal streptococci from agricultural sources. The findings may assist in developing approaches for assessing the risks to shellfishery industries of various fecal inputs into an estuary, which could then help local governmental authorities address the problem

Hydroacoustics as a tool to examine the effects of Marine Protected Areas and habitat type on marine fish communities

Abstract Hydroacoustic technologies are widely used in fisheries research but few studies have used them to examine the effects of Marine Protected Areas (MPAs). We evaluate the efficacy of hydroacoustics to examine the effects of closure to fishing and habitat type on fish populations in the Cabo Pulmo National Park (CPNP), Mexico, and compare these methods to Underwater Visual Censuses (UVC). Fish density, biomass and size were all significantly higher inside the CPNP (299%, 144% and 52% respectively) than outside in non-MPA control areas. These values were much higher when only accounting for the reefs within the CPNP (4715%, 6970% and 97% respectively) highlighting the importance of both habitat complexity and protection from fishing for fish populations. Acoustic estimates of fish biomass over reef-specific sites did not differ significantly from those estimated using UVC data, although acoustic densities were less due to higher numbers of small fish recorded by UVC. There is thus considerable merit in nesting UVC surveys, also providing species information, within hydroacoustic surveys. This study is a valuable starting point in demonstrating the utility of hydroacoustics to assess the effects of coastal MPAs on fish populations, something that has been underutilised in MPA design, formation and management

COPD classification models and mortality prediction capacity

Our aim was to assess the impact of comorbidities on existing COPD prognosis scores. Patients and methods: A total of 543 patients with COPD (FEV1 < 80% and FEV1/ FVC <70%) were included between January 2003 and January 2004. Patients were stable for at least 6 weeks before inclusion and were followed for 5 years without any intervention by the research team. Comorbidities and causes of death were established from medical reports or information from primary care medical records. The GOLD system and the body mass index, obstruction, dyspnea and exercise (BODE) index were used for COPD classification. Patients were also classified into four clusters depending on the respiratory disease and comorbidities. Cluster analysis was performed by combining multiple correspondence analyses and automatic classification. Receiver operating characteristic curves and the area under the curve (AUC) were calculated for each model, and the DeLong test was used to evaluate differences between AUCs. Improvement in prediction ability was analyzed by the DeLong test, category-free net reclassification improvement and the integrated discrimination index. Results: Among the 543 patients enrolled, 521 (96%) were male, with a mean age of 68 years, mean body mass index 28.3 and mean FEV1% 55%. A total of 167 patients died during the study follow-up. Comorbidities were prevalent in our cohort, with a mean Charlson index of 2.4. The most prevalent comorbidities were hypertension, diabetes mellitus and cardiovascular diseases. On comparing the BODE index, GOLDABCD, GOLD2017 and cluster analysis for pre-dicting mortality, cluster system was found to be superior compared with GOLD2017 (0.654 vs 0.722, P=0.006), without significant differences between other classification models. When cardiovascular comorbidities and chronic renal failure were added to the existing scores, their prognostic capacity was statistically superior (P<0.001). Conclusion: Comorbidities should be taken into account in COPD management scores due to their prevalence and impact on mortalit