475 research outputs found
Evaluation of Pt, Ni, and Ni–Mo electrocatalysts for hydrogen evolution on crystalline Si electrodes
The dark electrocatalytic and light photocathodic hydrogen evolution properties of Ni, Ni–Mo alloys, and Pt on Si electrodes have been measured, to assess the viability of earth-abundant electrocatalysts for integrated, semiconductor coupled fuel formation. In the dark, the activities of these catalysts deposited on degenerately doped p^+-Si electrodes increased in the order Ni < Ni–Mo ≤ Pt. Ni–Mo deposited on degenerately doped Si microwires exhibited activity that was very similar to that of Pt deposited by metal evaporation on planar Si electrodes. Under 100 mW cm^(−2) of Air Mass 1.5 solar simulation, the energy conversion efficiencies of p-type Si/catalyst photoelectrodes ranged from 0.2–1%, and increased in the order Ni ≈ Ni–Mo < Pt, due to somewhat lower photovoltages and photocurrents for p-Si/Ni–Mo relative to p-Si/Ni and p-Si/Pt photoelectrodes. Deposition of the catalysts onto microwire arrays resulted in higher apparent catalytic activities and similar photoelectrode efficiencies than were observed on planar p-Si photocathodes, despite lower light absorption by p-Si in the microwire structures
Nanostructured Nickel Phosphide as an Electrocatalyst for the Hydrogen Evolution Reaction
Nanoparticles of nickel phosphide (Ni_2P) have been investigated for electrocatalytic activity and stability for the hydrogen evolution reaction (HER) in acidic solutions, under which proton exchange membrane-based electrolysis is operational. The catalytically active Ni_2P nanoparticles were hollow and faceted to expose a high density of the Ni_2P(001) surface, which has previously been predicted based on theory to be an active HER catalyst. The Ni2P nanoparticles had among the highest HER activity of any non-noble metal electrocatalyst reported to date, producing H_2(g) with nearly quantitative faradaic yield, while also affording stability in aqueous acidic media
Factors Influencing Motivation to Perform Mental and Physical Tasks during the Initial Lockdown Period of the COVID-19 Pandemic
Drastic changes to lifestyles have occurred during the COVID-19 pandemic. A consequence of non-pharmaceutical interventions (NPIs) used against this health crisis, such as stay-at-home orders, has been increased isolation and less social interaction for a majority of people. For overall wellbeing, it is important to stay both physically and mentally active. However, for many individuals motivation may be a barrier. There are non-modifiable (e.g., sex, age) and modifiable factors (e.g., physical activity, diet) that may be associated with motivation to perform physical/mental tasks. PURPOSE: To explore if there is an association between non-modifiable and modifiable variables on motivation to perform mental/physical tasks under COVID-19 NPIs. METHODS: We collected data from 794 subjects using Qualtrics and each subject completed our survey once each week during April 1st to May 3rd of 2020. This is an ongoing study that will terminate when the COVID-19 pandemic ends. Survey questionnaires included demographics, personality traits, diet, physical activity levels, and motivation to perform mental/physical tasks. Multiple linear regression analyses were used for statistical analysis. RESULTS: Significant results include: a) those who reported a higher quality of diet (REAP-S score) (β=.015, p\u3c0.05; β=0.000, p\u3c0.001), exercised vigorously (β=0.005, p\u3c0.01; β=0.000, p\u3c0.001), and reduced their sedentary time (β=.000, p\u3c0.01; β=.000, p\u3c0.001), reported higher motivation to perform both mental and physical tasks, respectively; b) those who were employed (β=.043, p\u3c0.05) and had higher grit (β=.041, p\u3c0.05) were more motivated to perform physical tasks; and c) lower trait physical energy was associated with greater motivation to perform mental tasks (β=.027, p\u3c0.05). CONCLUSION: Our findings indicate that living a healthy lifestyle is associated with motivation to perform both mental and physical tasks during the initial lockdown period of the COVID-19 pandemic. These preliminary results support the continuation of data collection. Future research should focus on trying to determine the directionality of the relationship between healthy lifestyle behaviors and motivation
The Composite Task Reveals Stronger Holistic Processing in Children than Adults for Child Faces
Background: While own-age faces have been reported to be better recognized than other-age faces, the underlying cause of this phenomenon remains unclear. One potential cause is holistic face processing, a special kind of perceptual and cognitive processing reserved for perceiving upright faces. Previous studies have indeed found that adults show stronger holistic processing when looking at adult faces compared to child faces, but whether a similar own-age bias exists in children remains to be shown. Methodology/Principal Findings: Here we used the composite face task – a standard test of holistic face processing – to investigate if, for child faces, holistic processing is stronger for children than adults. Results showed child participants (8–13 years) had a larger composite effect than adult participants (22–65 years). Conclusions/Significance: Our finding suggests that differences in strength of holistic processing may underlie the ownage bias on recognition memory. We discuss the origin of own-age biases in terms of relative experience, face-space tuning, and social categorization
Understanding the UK hospital supply chain in an era of patient choice
Author Posting © Westburn Publishers Ltd, 2011. This is a post-peer-review, pre-copy-edit version of an article which has been published in its definitive form in the Journal of Marketing Management, and has been posted by permission of Westburn Publishers Ltd for personal use, not for redistribution. The article was published in Journal of Marketing Management, 27(3-4), 401 - 423, doi:10.1080/0267257X.2011.547084 http://dx.doi.org/10.1080/0267257X.2011.547084The purpose of this paper is to investigate the UK hospital supply chain in light of recent government policy reform where patients will have, inter alia, greater choice of hospital for elective surgery. Subsequently, the hospital system should become far more competitive with supply chains having to react to these changes as patient demand becomes less predictable. Using a qualitative case study methodology, hospital managers are interviewed on a range of issues. Views on the development of the hospital supply chain in different phases are derived, and are used to develop a map of the current hospital chain. The findings show hospital managers anticipating some significant changes to the hospital supply chain and its workings as Patient Choice expands. The research also maps the various aspects of the hospital supply chain as it moves through different operational phases and highlights underlying challenges and complexities. The hospital supply chain, as discussed and mapped in this research, is original work given there are no examples in the literature that provide holistic representations of hospital activity. At the end, specific recommendations are provided that will be of interest to service to managers, researchers, and policymakers
An examination of cancer epidemiology studies among populations living close to toxic waste sites
<p>Abstract</p> <p>Background</p> <p>Toxic waste sites contain a broad range of suspected or confirmed human carcinogens, and remain a source of concern to many people, particularly those living in the vicinity of a site. Despite years of study, a consensus has not emerged regarding the cancer risk associated with such sites.</p> <p>Methods</p> <p>We examined the published, peer-reviewed literature addressing cancer incidence or mortality in the vicinity of toxic waste sites between 1980 and 2006, and catalogued the methods employed by such studies.</p> <p>Results</p> <p>Nineteen studies are described with respect to eight methodological criteria. Most were ecological, with minimal utilization of hydrogeological or air pathway modeling. Many did not catalogue whether a potable water supply was contaminated, and very few included contaminant measurements at waste sites or in subjects' homes. Most studies did not appear to be responses to a recognized cancer mortality cluster. Studies were highly variable with respect to handling of competing risk factors and multiple comparisons.</p> <p>Conclusion</p> <p>We conclude that studies to date have generated hypotheses, but have been of limited utility in determining whether populations living near toxic waste sites are at increased cancer risk.</p
Impact of tetrachloroethylene-contaminated drinking water on the risk of breast cancer: Using a dose model to assess exposure in a case-control study
BACKGROUND: A population-based case-control study was undertaken in 1997 to investigate the association between tetrachloroethylene (PCE) exposure from public drinking water and breast cancer among permanent residents of the Cape Cod region of Massachusetts. PCE, a volatile organic chemical, leached from the vinyl lining of certain water distribution pipes into drinking water from the late 1960s through the early 1980s. The measure of exposure in the original study, referred to as the relative delivered dose (RDD), was based on an amount of PCE in the tap water entering the home and estimated with a mathematical model that involved only characteristics of the distribution system. METHODS: In the current analysis, we constructed a personal delivered dose (PDD) model that included personal information on tap water consumption and bathing habits so that inhalation, ingestion, and dermal absorption were also considered. We reanalyzed the association between PCE and breast cancer and compared the results to the original RDD analysis of subjects with complete data. RESULTS: The PDD model produced higher adjusted odds ratios than the RDD model for exposures > 50(th )and >75(th )percentile when shorter latency periods were considered, and for exposures < 50(th )and >90(th )percentile when longer latency periods were considered. Overall, however, the results from the PDD analysis did not differ greatly from the RDD analysis. CONCLUSION: The inputs that most heavily influenced the PDD model were initial water concentration and duration of exposure. These variables were also included in the RDD model. In this study population, personal factors like bath and shower temperature, bathing frequencies and durations, and water consumption did not differ greatly among subjects, so including this information in the model did not significantly change subjects' exposure classification
A treatment evaluator tool to monitor the real-world effectiveness of inhaled aztreonam lysine in cystic fibrosis
Background: Studies are required that evaluate real-world outcomes of inhaled aztreonam lysine in patients with cystic fibrosis (CF). Methods: Our treatment-evaluator tool assessed the effectiveness of inhaled aztreonam in routine practice in 117 CF patients across four time periods (6–12 (P2) and 0–6 months (P1) pre-initiation, and 0–6 (T1) and 6–12 months (T2) post-initiation). Outcomes were: changes in %-predicted forced expiratory volume in 1 s (FEV1), body-mass index (BMI), hospitalisation days and intravenous antibiotic usage. Results: Median FEV1% predicted for each 6-month period was 38.9%, 34.6%, 37.1% and 36.5%; median change was − 2.0% between P2 and P1, increasing to + 0.6% (p < 0.001) between P1 and T1. Annualised hospital bed-days was reduced (p = 0.05) post-initiation, as was intravenous antibiotics days (p = 0.001). BMI increased over 6 months post-initiation (p ≤ 0.001). Conclusions: In patients with CF in routine practice, inhaled aztreonam lysine is associated with improved lung function and weight, and reduced hospitalisation and intravenous antibiotic use
Restoring Cystic Fibrosis Transmembrane Conductance Regulator Function Reduces Airway Bacteria and Inflammation in People with Cystic Fibrosis and Chronic Lung Infections
Rationale: Previous work indicates that ivacaftor improves cystic fibrosis transmembrane conductance regulator (CFTR) activity and lung function in people with cystic fibrosis and G551D-CFTR mutations but does not reduce density of bacteria or markers of inflammation in the airway. These findings raise the possibility that infection and inflammation may progress independently of CFTR activity once cystic fibrosis lung disease is established.
Objectives: To better understand the relationship between CFTR activity, airway microbiology and inflammation, and lung function in subjects with cystic fibrosis and chronic airway infections.
Methods: We studied 12 subjects with G551D-CFTR mutations and chronic airway infections before and after ivacaftor. We measured lung function, sputum bacterial content, and inflammation, and obtained chest computed tomography scans.
Measurements and Main Results: Ivacaftor produced rapid decreases in sputum Pseudomonas aeruginosa density that began within 48 hours and continued in the first year of treatment. However, no subject eradicated their infecting P. aeruginosa strain, and after the first year P. aeruginosa densities rebounded. Sputum total bacterial concentrations also decreased, but less than P. aeruginosa. Sputum inflammatory measures decreased significantly in the first week of treatment and continued to decline over 2 years. Computed tomography scans obtained before and 1 year after ivacaftor treatment revealed that ivacaftor decreased airway mucous plugging.
Conclusions: Ivacaftor caused marked reductions in sputum P. aeruginosa density and airway inflammation and produced modest improvements in radiographic lung disease in subjects with G551D-CFTR mutations. However, P. aeruginosa airway infection persisted. Thus, measures that control infection may be required to realize the full benefits of CFTR-targeting treatments
Produção de memórias falsas com listas de associados : análise do efeito do nível de processamento e da natureza da prova de memória
As memórias falsas têm sido amplamente estudadas com base num procedimento experimental designado paradigma DRM (Deese/Roediger/McDermott). Esse paradigma promove a criação de ilusões de memória a partir da apresentação de listas de palavras associadas a um item que não consta da lista. Uma das linhas de investigação com o paradigma DRM visa identificar o momento da criação das falsas memórias e explicar os mecanismos que estão na sua origem. Neste artigo, pretendemos fazer uma revisão da investigação sobre o efeito do nível de processamento e da natureza da tarefa de memória na facilitação ou inibição da produção de memórias falsas com listas de associados semânticos.False memories have been widely studied using an
experimental procedure called DRM paradigm (Deese/Roediger/McDermott). This
paradigm produces memory illusions due to the presentation of lists of words
associated to a critical nonpresented word. One line of research on this topic aims at
identifying the moment when the false memories are created and the explanation of
the mechanisms underling false memories. In this paper we present a review about
the effect of level-of-processing and the nature of memory task for the boost or
inhibition of false memories created by means of lists of semantic associates.Le paradigme DRM (Deese/Roediger/McDermott) est
un des plus connus et plus robustes parmi les études des faux mémoires dans le
contexte du laboratoire. Ce paradigme permet la création d illusions de mémoire à
partir des mots sémantiquement associés à un item qui n a pas été présenté. Au milieu
des investigations basées sur le paradigme DRM il y a des études dont l objectif est
d identifier e d´expliquer les mécanismes qui sont à l origine de la production des
faux mémoires. Plus spécifiquement, on a pour but de faire une révision de la
recherche sur l effet du niveau de codification et de la nature des tâches de mémoire
sur la facilitation ou l´inhibition de la production de faux mémoires à partir des mots
sémantiquement associés.Los falsos recuerdos han sido muy estudiados mediante
la aplicación del paradigma DRM (Deese/Roediger/McDermott). El paradigma
permite producir ilusiones de memoria tras la presentación de listas de palabras
asociadas a una palabra que no se incluye en la lista. Una de las líneas de investigación
que utilizan el paradigma DRM busca identificar el preciso momento de la creación
de falsos recuerdos y explicar los mecanismos que originan ese efecto. El objetivo de
este artículo es hacer una revisión de la investigación sobre el efecto de los niveles
de procesamiento y la naturaleza de la tarea de memoria en la facilitación y inhibición
de la producción de falsos recuerdos con listas de asociados semánticos.Fundação para a Ciência e a Tecnologia (FCT)Centro de Investigação em Psicologia da Universidade do Minho (CIPsi
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