538 research outputs found
Wear studies made of slip rings and gas bearing components
Neutron activation analysis techniques were employed for the study of the wear and performance characteristics of slip ring and rotor assemblies and of the problems arising from environmental conditions with special reference to surface contamination. Results showed that the techniques could be successfully applied to measurement of wear parameters
Analysis of solid-rocket effluents for aluminum, silicon, and other trace elements by neutron activation analysis
The sensitivity and reliability of neutron activation analysis in detecting trace elements in solid rocket effluents are discussed. Special attention was given to Al and Si contaminants. The construction and performance of a thermal column irradiation unit was reported
Ant colonies: building complex organizations with minuscule brains and no leaders
Thus far the articles in the series JOD calls the “Organization Zoo” have employed the notion of a “zoo” metaphorically to describe an array of human institutions. Here we take the term literally to consider the design of the most complex organizations in the living world beside those of humans, a favorite of insect zoos around the world: ant colonies. We consider individuality and group identity in the functioning of ant organizations; advantages of a flat organization without hierarchies or leaders; self-organization; direct and indirect communication; job specialization; labor coordination; and the role of errors in innovation. The likely value and limitations of comparing ant and human organizations are briefly examined
Measuring Cognitive Reflection without Maths: Development and Validation fo the Verbal Cognitive Reflection Test
The Cognitive Reflection Test (CRT) became popular for its impressive power to predict how well people reason and make decisions. Despite the popularity of the CRT, a major issue complicates its interpretation: the numerical nature of the CRT confounds reflection ability with mathematical ability. We have addressed this issue by developing the Verbal CRT (CRT-V), a novel 10-item measure of cognitive reflection (https://osf.io/xehbv/), using non-mathematical problems with good statistical and psychometric properties and with low familiarity. First, we selected suitable items with relatively low familiarity and optimal difficulty as identified in two different populations (Studies 1 and 2) and with high content validity as judged by an expert panel (Study 3). Second, we demonstrated good criterion and construct validity for the test in different populations with a wide range of variables (Studies 4-6, 8) and a good internal consistency and test-retest reliability (Study 7). The Verbal CRT was less associated with math anxiety, objective and subjective numeracy than the original CRT and it was test equivalent across gender, age groups and administration setting. In contrast with the original CRT (Hedge’s g = 0.29, 95% CI[0.17, 0.40]), the Verbal CRT showed no gender differences (Hedge’s g = -0.06, 95% CI[-0.18, 0.06]). The Verbal CRT can complement existing, numerical, tests of cognitive reflection
Design and validation of a three-instrument toolkit for the assessment of competence in electrocardiogram rhythm recognition
Background: Rapid and accurate interpretation of cardiac arrhythmias by nurses has been linked with safe practice and positive patient outcomes. Although training in electrocardiogram (ECG) rhythm recognition is part of most undergraduate nursing programmes, research continues to suggest that nurses and nursing students lack competence in recognising cardiac rhythms. In order to promote patient safety, nursing educators must develop valid and reliable assessment tools that allow the rigorous assessment of this competence before nursing students are allowed to practise without supervision.
Aim: To develop and psychometrically evaluate a toolkit to holistically assess competence in ECG rhythm recognition.
Methods: Following a convenience sampling technique, 293 nursing students from a nursing faculty in a Spanish university were recruited for the study. The following three instruments were developed and psychometrically tested: a knowledge assessment tool (ECG-KAT), a skills assessment tool (ECG-SAT) and a self-efficacy assessment tool (ECG-SES). Reliability and validity (content, criterion and construct) of these tools were meticulously examined.
Results: A high Cronbach’s alpha coefficient demonstrated the excellent reliability of the instruments (ECG-KAT=0.89; ECG-SAT=0.93; ECG-SES=0.98). An excellent context validity index (S-CVI/Ave>0.94) and very good criterion validity were evidenced for all the tools. Regarding construct validity, principal component analysis revealed that all items comprising the instruments contributed to measure knowledge, skills or self-efficacy in ECG rhythm recognition. Moreover, known-groups analysis showed the tools’ ability to detect expected differences in competence between groups with different training experiences.
Conclusion: The three-instrument toolkit developed showed excellent psychometric properties for measuring competence in ECG rhythm recognition
Recombinant MVA-prime elicits neutralizing antibody responses by inducing antigen-specific B cells in the germinal center.
The RV144 HIV-1 vaccine trial has been the only clinical trial to date that has shown any degree of efficacy and associated with the presence of vaccine-elicited HIV-1 envelope-specific binding antibody and CD4+ T-cell responses. This trial also showed that a vector-prime protein boost combined vaccine strategy was better than when used alone. Here we have studied three different priming vectors-plasmid DNA, recombinant MVA, and recombinant VSV, all encoding clade C transmitted/founder Env 1086 C gp140, for priming three groups of six non-human primates each, followed by a protein boost with adjuvanted 1086 C gp120 protein. Our data showed that MVA-priming favors the development of higher antibody binding titers and neutralizing activity compared with other vectors. Analyses of the draining lymph nodes revealed that MVA-prime induced increased germinal center reactivity characterized by higher frequencies of germinal center (PNA <sup>hi</sup> ) B cells, higher frequencies of antigen-specific B-cell responses as well as an increased frequency of the highly differentiated (ICOS <sup>hi</sup> CD150 <sup>lo</sup> ) Tfh-cell subset
On the Multi-Language Construction
Modern software is no more developed in a single programming language. Instead, programmers tend to exploit cross-language interoperability mechanisms to combine code stemming from different languages, and thus yielding fully-fledged multi-language programs. Whilst this approach enables developers to benefit from the strengths of each single-language, on the other hand it complicates the semantics of such programs. Indeed, the resulting multi-language does not meet any of the semantics of the combined languages. In this paper, we broaden the boundary functions-based approach a la Matthews and Findler to propose an algebraic framework that provides a constructive mathematical notion of multi-language able to determine its semantics. The aim of this work is to overcome the lack of a formal method (resp., model) to design (resp., represent) a multi-language, regardless of the inherent nature of the underlying languages. We show that our construction ensures the uniqueness of the semantic function (i.e., the multi-language semantics induced by the combined languages) by proving the initiality of the term model (i.e., the abstract syntax of the multi-language) in its category
External agents of change: a 10-year trend study of garden visitor behaviour in England.
Changes in people’s behaviour over time can be understood through three distinct elements: their age, a period of time and their birth cohort. Age is a key demographic in many leisure studies but less frequently a period of years is used in longitudinal studies. Changes to a birth cohort (a term often used synonymously with a generation) are rarely examined. This study adopts all three measures to demonstrate the complexity of change over time and also offers a greater understanding of change in people’s leisure behaviour, specifically those who visit gardens in England. A trend study consisting of two cross-sectional studies, 10 years apart, was undertaken through resident surveys (n = 341 and 392). These examined factors external to the individual which might influence their behaviour. The results demonstrate that changes in environmental, social and technological factors such as the weather, family and friends and the Internet have impacts that are complex and which are sometimes concealed within different age groups and cohorts over the decade. Notably, no single factor was identified where there was change across the period, all the age groups and all five cohorts, confirming that any change in people’s behaviour is not universal
Metabolism before, during and after anaesthesia in colic and healthy horses
<p>Abstract</p> <p>Background</p> <p>Many colic horses are compromised due to the disease state and from hours of starvation and sometimes long trailer rides. This could influence their muscle energy reserves and affect the horses' ability to recover. The principal aim was to follow metabolic parameter before, during, and up to 7 days after anaesthesia in healthy horses and in horses undergoing abdominal surgery due to colic.</p> <p>Methods</p> <p>20 healthy horses given anaesthesia alone and 20 colic horses subjected to emergency abdominal surgery were anaesthetised for a mean of 228 minutes and 183 minutes respectively. Blood for analysis of haematology, electrolytes, cortisol, creatine kinase (CK), free fatty acids (FFA), glycerol, glucose and lactate was sampled before, during, and up to 7 days after anaesthesia. Arterial and venous blood gases were obtained before, during and up to 8 hours after recovery. Gluteal muscle biopsy specimens for biochemical analysis of muscle metabolites were obtained at start and end of anaesthesia and 1 h and 1 day after recovery.</p> <p>Results</p> <p>Plasma cortisol, FFA, glycerol, glucose, lactate and CK were elevated and serum phosphate and potassium were lower in colic horses before anaesthesia. Muscle adenosine triphosphate (ATP) content was low in several colic horses. Anaesthesia and surgery resulted in a decrease in plasma FFA and glycerol in colic horses whereas levels increased in healthy horses. During anaesthesia muscle and plasma lactate and plasma phosphate increased in both groups. In the colic horses plasma lactate increased further after recovery. Plasma FFA and glycerol increased 8 h after standing in the colic horses. In both groups, plasma concentrations of CK increased and serum phosphate decreased post-anaesthesia. On Day 7 most parameters were not different between groups. Colic horses lost on average 8% of their initial weight. Eleven colic horses completed the study.</p> <p>Conclusion</p> <p>Colic horses entered anaesthesia with altered metabolism and in a negative oxygen balance. Muscle oxygenation was insufficient during anaesthesia in both groups, although to a lesser extent in the healthy horses. The post-anaesthetic period was associated with increased lipolysis and weight loss in the colic horses, indicating a negative energy balance during the first week post-operatively.</p
Measuring substance use in the club setting: a feasibility study using biochemical markers
<p>Abstract</p> <p>Background</p> <p>During the last few decades the use of club drugs (e.g., cocaine, amphetamines) has been of increased concern in nightlife settings. Traditionally, surveys have been used to estimate the use of club drugs, however, they mostly rely on self-reports which may not be accurate. Recent advances have allowed for readily accessible drug testing methods such as oral fluid drug testing. Nevertheless, research using oral fluid sampling to measure the frequency of drug use in the club environment is scarce. The objective of this study is to evaluate the feasibility of measuring the frequency of alcohol and drug use among Swedish clubbers using breath alcohol and oral fluid drug testing.</p> <p>Method</p> <p>The setting was a 40 hour electronic music dance event (EMDE) on a cruise ship on the Baltic Sea, departing from Sweden, with 875 passengers. Groups of participants at the EMDE were randomly invited to participate. Data were collected with face-to-face and self-administered questionnaires. Further, oral fluid samples were collected to determine illicit drug use, and blood alcohol concentration (BAC) levels were measured using a breath analyzer.</p> <p>Results</p> <p>A total of 422 passengers were asked to participate in the study whereof 21 declined (5.0% refusal rate). Of the 401 study participants (accounting for 45.8% of all attendees), 5 declined oral fluid drug testing. Results show that there was a discrepancy between self-reported and actual drug use as 10.1% of the participants were positive on illicit drug use (amphetamines, ecstasy/MDMA, cannabis, cocaine), while only 3.7% of the participants reported drug use during the last 48 hours. The average BAC level was 0.10% and 23.7% had BAC levels ≥ 0.15%, while 5.9% had levels below the detection limit. The mean BAC levels for the illicit drug users were significantly higher (<it>p </it>= 0.004) than for non-drug users (0.13% vs. 0.10%). Self-reported AUDIT-C scores (using a threshold of ≥ 5 for men and ≥ 4 for women) revealed that 76.0% of the men and 80.7% of the women had risky alcohol consumption patterns.</p> <p>Conclusion</p> <p>This study indicates that it is feasible to conduct breath alcohol and oral fluid drug testing in a Swedish club setting.</p
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