3,776 research outputs found

    Air-Gap Detection in Dielectric Materials by a Step-Frequency Microwave Technique

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    Most microwave NDE has been performed using continuous wave excitation and reception, due to the general availability of such equipment and the acceptable procedure of extracting information from the amplitude and phase of such signals. With the availability of sources that can be swept over a band of frequencies, the amplitude and phase information can be converted via the Fourier Transformation to the impulse response in the time domain. Instead of searching for changes in the amplitude and phase of microwave reflected from boundaries, interfaces, and defects, this time domain approach concentrates on the recognition of “echoes”. This approach is implicit in some of the more complex approaches in microwave imaging [1–3]. It is the purpose of this paper to demonstrate that this approach facilitates the detection of internal defects using microwave, in a manner similar to the practice of pulse-echo ultrasound. The time delay for a microwave “echo” is related to the location, and the Fourier transformed amplitude is related to some characteristics of the defect inside the material

    Energetic consequences of time-activity budgets for a breeding seabird

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    How animals allocate their time to different behaviours has important consequences for their overall energy budget and reflects how they function in their environment. This potentially affects their ability to successfully reproduce, thereby impacting their fitness. We used accelerometers to record time-activity budgets of 21 incubating and chick-rearing kittiwakes (Rissa tridactyla) on Puffin Island, UK. These budgets were examined on a per day and per foraging trip basis. We applied activity-specific estimates of energy expenditure to the kittiwakes\u27 time-activity budgets in order to identify the costs of variation in their allocation of time to different behaviours. Estimates of daily energy expenditure for incubating kittiwakes averaged 494 ± 20 kJ d-1 while chick-rearing birds averaged 559 ± 11 kJ d-1. Time-activity budgets highlighted that kittiwakes did not spend a large proportion of their time flying during longer foraging trips, or during any given 24-h period. With time spent flying highlighted as the driving factor behind elevated energy budgets, this suggests behavioural compensation resulting in a possible energetic ceiling to their activities. We also identified that kittiwakes were highly variable in the proportion of time they spent either flying or on the water during foraging trips. Such variation meant that using forage trip duration alone to predict energy expenditure gave a mean error of 19% when compared to estimates incorporating the proportion of a foraging trip spent flying. We have therefore highlighted that trip duration alone is not an accurate indicator of energy expenditure

    Systematic review of the methods used in economic evaluations of targeted physical activity and sedentary behaviour interventions

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    The burden of noncommunicable diseases (NCD) on health systems worldwide is substantial. Physical inactivity and sedentary behaviour are major risk factors for NCD. Previous attempts to understand the value for money of preventative interventions targeting physically inactive individuals have proved to be challenging due to key methodological challenges associated with the conduct of economic evaluations in public health. A systematic review was carried out across six databases (Medline, SPORTSDiscus, EconLit, PsychINFO, NHS EED, HTA) along with supplementary searches. The review examines how economic evaluations published between 2009-March 2017 have addressed methodological challenges with the aim of bringing to light examples of good practice for future studies. Fifteen economic evaluations from four high-income countries were retrieved; there is a dearth of studies targeting sedentary behaviour as an independent risk factor from physical activity. Comparability of studies from the healthcare and societal perspectives were limited due to analysts’ choice in cost categories, valuation technique and time horizon differing substantially. The scarcity of and inconsistencies across economic evaluations for these two behaviours have exposed a mismatch between calls for more preventative action to tackle NCD and the lack of information available on how resources may be optimally allocated in practice. Consequently, this paper offers a table of recommendations on how future studies can be improved

    Electrochemical communication with the inside of cells using micro-patterned vertical carbon nanofibre electrodes

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    With the rapidly increasing demands for ultrasensitive biodetection, the design and applications of new nano-scale materials for development of sensors based on optical and electrochemical transducers have attracted substantial interest. In particular, given the comparable sizes of nanomaterials and biomolecules, there exist plenty of opportunities to develop functional nanoprobes with biomolecules for highly sensitive and selective biosensing, shedding new light on cellular behaviour. Towards this aim, herein we interface cells with patterned nano-arrays of carbon nanofibers forming a nanosensor-cell construct. We show that such a construct is capable of electrochemically communicating with the intracellular environment.This work was supported by the Leverhulme Trust [grant numbers F/00 094/BD, ECF/2013-603]; the Biotechnology and Biological Sciences Research Council [grant number BB/L017059/1]; the European Research Council [Consolidator Grant, number 614787], the Engineering and Physical Sciences Research Council [EP/K027263/1]; and the NC3Rs [grant number NC/L00058X/1]

    The views of older women towards mammographic screening: a qualitative and quantitative study

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    Purpose: Mammographic screening has improved breast cancer survival in the screened age group. This improved survival has not been seen in older women (>70 years) where screening uptake is low. This study explores the views, knowledge and attitudes of older women towards screening. Methods: Women (>70) were interviewed about breast screening. Interview findings informed the development of a questionnaire which was sent to 1000 women (>70) to quantify their views regarding screening. Results: Twenty-six women were interviewed and a questionnaire designed. The questionnaire response rate was 48.3% (479/992). Over half (52.9%, 241/456) of respondents were unaware they could request mammography by voluntary self-referral and were unaware of how to arrange this. Most (81.5% 383/470) had not attended breast screening since turning 70. Most (75.6%, 343/454) felt screening was beneficial and would attend if invited. Most, (90.1%, 412/457) felt screening should be offered to all women regardless of age or health. Conclusions: There is a lack of knowledge about screening in older women. The majority felt that invitation to screening should be extended to the older age group regardless of age or health. The current under-utilised system of voluntary self referral is not supported by older women

    A strategy for the characterization of minute chromosome rearrangements using multiple color fluorescence in situ hybridization with chromosome-specific DNA libraries and YAC clones

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    The identification of marker chromosomes in clinical and tumor cytogenetics by chromosome banding analysis can create problems. In this study, we present a strategy to define minute chromosomal rearrangements by multicolor fluorescence in situ hybridization (FISH) with whole chromosome painting probes derived from chromosome-specific DNA libraries and Alu-polymerase chain reaction (PCR) products of various region-specific yeast artificial chromosome (YAC) clones. To demonstrate the usefulness of this strategy for the characterization of chromosome rearrangements unidentifiable by banding techniques, an 8p+ marker chromosome with two extra bands present in the karyotype of a child with multiple anomalies, malformations, and severe mental retardation was investigated. A series of seven-color FISH experiments with sets of fluorochrome-labeled DNA library probes from flow-sorted chromosomes demonstrated that the additional segment on 8p+ was derived from chromosome 6. For a more detailed characterization of the marker chromosome, three-color FISH experiments with library probes specific to chromosomes 6 and 8 were performed in combination with newly established telomeric and subtelomeric YAC clones from 6q25, 6p23, and 8p23. These experiments demonstrated a trisomy 6pter6p22 and a monosomy 8pter8p23 in the patient. The present limitations for a broad application of this strategy and its possible improvements are discusse

    The Relationship Between HR Practices and Firm Performance: Examining Causal Order

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    Significant research attention has been devoted to examining the relationship between HR practices and firm performance, and the research support has assumed HR as the causal variable. Using data from 45 business units (with 62 data points), this study examines how measures of HR practices correlate with past, concurrent, and future operational performance measures. The results indicate that correlations with performance measures at all three times are both high and invariant, and that controlling for past or concurrent performance virtually eliminates the correlation of HR with future performance. Implications are discussed

    A cross-sectional study of memory and executive functions in patients with sporadic inclusion body myositis

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    INTRODUCTION: Sporadic inclusion body myositis (IBM) is a degenerative and inflammatory acquired myopathy characterised by muscle deposition of various proteins typically associated with Alzheimer's disease and other neurodegenerative diseases. While cognitive impairment is not noted as a clinical feature of IBM, evidence is lacking. We aimed to investigate whether cognitive performance of patients with IBM differs from population norms, focussing on cognitive domains affected in early Alzheimer's disease (memory, executive function), and to test whether disease duration and the level of disability of IBM are associated with cognitive function. METHODS: Twenty-four patients with IBM (mean [SD] age 62.0 [7.2] years; disease duration 9.6 [4.8] years) were assessed cross-sectionally on neuropsychological tests covering multiple cognitive domains, including the Preclinical Alzheimer Cognitive Composite (PACC). Performance was compared to published normative data adjusted for age, sex and education (National Alzheimer's Coordinating Center; N = 3268). Associations were examined between PACC score, disease duration and level of disability (assessed using the IBM Functional Rating Scale [IBMFRS]). RESULTS: Across all cognitive tests, group performance was within ±1SD of the normative mean. There was no evidence of associations between PACC score and either disease duration (ρ = -0.04, p = 0.87) or IBMFRS total score (ρ = 0.14, p = 0.52). DISCUSSION: Memory and executive function in patients with IBM did not differ from normative data, and we observed no evidence of associations between the cognitive composite and disease duration or level of disability. This addresses a question frequently asked by patients, and will be of value for clinicians and patients alike. This article is protected by copyright. All rights reserved

    Parton Distributions for Event Generators

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    In this paper, conventional Global QCD analysis is generalized to produce parton distributions optimized for use with event generators at the LHC. This optimization is accomplished by combining the constraints due to existing hard-scattering experimental data with those from anticipated cross sections for key representative SM processes at LHC (by the best available theory) as joint input to the global analyses. The PDFs obtained in these new type of global analyses using matrix elements calculated in any given order will be best suited to work with event generators of that order, for predictions at the LHC. This is most useful for LO event generators at present. Results obtained from a few candidate PDF sets (labeled as CT09MCS, CT09MC1 and CT09MC2) for LO event generators produced in this way are compared with those from other approaches.Comment: 35 pages, 19 figures, and 4 table
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