485 research outputs found
A Predictive Model Of Avian Influenza Among Poultry In Egypt
Background: Avian Influenza (H5N1) has become entrenched in Egypt since its emergence in 2006. Control measures have failed and surveillance systems remain inadequate. A relatively new method for regression called Random Forests is presented here with the goal of providing accurate and timely predictions of the weekly number of outbreaks in each of the Egyptian governorates.
Methods: Predictions were generated from Random Forests models using outbreak data from the FAO EMPRES-i database, and local weather data from Weather Underground. This data was lagged by one and two weeks in order to make prospective predictions with the current week\u27s data in the future. Model performance was assessed using a variety of methods.
Results: The percent of the variance in observed outbreaks explained by the model in each of the governorates varied greatly, ranging between 20 and 60 percent in governorates with high and medium outbreak activity. The models typically predicted poorly in governorates with low activity. Linear regression of the observed outbreaks on the predicted values provided evidence that while outbreaks were consistently underpredicted across all governorates, predictions in some models tracked observed outbreaks quite accurately.
Discussion: The varying levels of model performance in each of the governorates raises many questions about why this is. While we cannot deduce these reasons from the models themselves, public health officials can use the lessons learned here as a guide to focus future research to better understand what is occurring. Predictive models can be used to evaluate local surveillance systems, and find additional covariates for the model to determine the spatio-temporal risk of avian influenza. As a result of better surveillance data and more complete models, control and prevention measures may be more effectively put in place where and when they are needed most
Recommendations for high intensity upper body exercise testing
Introduction: For given submaximal and maximal peak power outputs aerobic responses to upper body exercise are different to those for lower body exercise (Sawka, 1986: Exercise & Sport Sciences Reviews, 14, 175-211). However, much less is known regarding responses to exercise intensities at and around peak oxygen up take (VO2peak). Purpose: The purpose of this study was to determine the metabolic responses during arm crank ergometry (ACE) below, at and above peak oxygen uptake and to help establish exercise testing guidelines for high intensity upper body exercise. Methods: Following institutional ethical approval fourteen male students (Age 21.1, s = 6.1 years and 2.44 s=0.44 VO2peak) volunteered to take part in this study. Each participant exercised on a table mounted cycle ergometer (Monark 894E, Monark Exercise AB, Sweden). After habituation peak minute power (PMP) was calculated from an incremental test. Subsequently each participant completed four continuous work tests (CWT) to volitional exhaustion at 80%, 90%, 100% and 110% of PMP. All tests were completed at 70 revâmin-1 with a minimum of 48-h between tests and the order was counterbalanced. Each CWT was preceded by a 5 min warm-up, loaded with a mass corresponding to the participants 80% PMP for 20 s at minutes 2, 3 and 4. Oxygen uptake (VO2), respiratory exchange ratio (RER), heart rate (HR) and ratings of perceived exertion for the arms (local (RPEL) and cardiorespiratory strain (RPECR) were recorded at 1 min, 2 min and at volitional exhaustion. The EMG responses at three sites (flexor carpi ulnaris, biceps brachii and triceps brachii lateral) were recorded using double-differential (16-3000 Hz bandwidth, x300 gain), bipolar, active electrodes (MP-2A, Linton, Norfolk, UK). Electromyographic data were sampled at 1000 Hz and filtered using a 20 to 500 Hz band-pass filter (MP150 Data Acquisition and AcqKnowledge 4.0, Biopac, Goleta, CA). The EMG signals for each muscle were root mean squared (RMS) with a 500-ms sample window. The signal was then normalised, prior to each CWT, as a percentage of the mean of 3 sets of 10 duty cycles completed during the warm-up (see above) when the participants 80% PMP for 20 s was applied. Time to exhaustion (Tlim) was recorded as the performance outcome measure. Data for Tlim were analysed using one-way analysis of variance. Differences in EMG, VO2, RER, HR, RPEL and RPECR were analysed using separate two-way analysis of variance with repeated measures (trial x time). All analyses were performed using the Statistical Package for Social Sciences ( 17.0; SPSS Inc., Chicago, IL). Individual differences in means were located using Bonferroni post-hoc correction. Significance was accepted at P < 0.05. Results: As resistive load increased Tlim decreased (611 s=194, 397 s=99, 268 s=90, 206 s=67s, respectively; P < 0.001, ES = 0.625). Post-hoc analysis revealed that Tlim using 80%PMP was longer than for 90%, 100% and 110% PMP trials (P < 0.001) and 90% was longer than both 100% and 110% PMP trials (P = 0.079, P = 0.001). At exhaustion VO2 was similar across trials (P = 0.413, ES = 0.053), although 80% PMP VO2 tended to be less (2.10 s=0.32 l·min-1) than for 90% (2.29 s=0.37), 100% (2.33 s=0.49) and 110% (2.26 s=0.34). Also, 80% PMP VO2 was less than VO2peak (P = 0.013). There were differences in RER at Tlim (P < 0.001, ES = 0.593) with values increasing with % PMP (1.15 s=0.07, 1.26 s=0.07, 1.36 s=0.10, 1.40 s=0.09, respectively). There were no differences across trials for HR at Tlim (~173 (12); P = 0.834, ES = 0.016) and HR was proportional to %PMP at 1 min, and 2 min. For flexor carpi ulnaris there was an increase in activation as exercise intensity increased (P < 0.001, ES = 0.245). There were a similar responses for biceps brachii and triceps brachii demonstrating an increase in activation with exercise intensity (P <0.001, ES = 0.137, P < 0.001, ES = 0.163, respectively). No differences for RPEL and RPECR were observed at Tlim. Discussion: There was a clear response of Tlim with intensity as expected for lower body exercise (Hill et al., 2002: Medicine and Science in Sports and Exercise, 34(4), 709-714). Despite differences in Tlim across exercise intensities VO2, HR and RPE were similar at exhaustion indicating a functional cardiorespiratory maximum had been reached. As indicated by the RER an increased activation of the anaerobic metabolism with greater exercise intensities (100% and 110%) is likely and therefore this may represent a greater anaerobic component at these two intensities. The increase in EMG activity with intensity could indicate an increase activity with an increase in exercise intensity. Conclusion: It is recommended that due to the combination of muscle activation, oxygen uptake and Tlim that an exercise intensity of 90% or 100% of PMP could be used for high intensity upper body exercise testing
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Once upon a time, there was a fabulous funambulist: What children learn about the âhigh-levelâ vocabulary they encounter while listening to stories
Previous research has shown that listening to stories supports vocabulary growth in preschool and school-aged children and that lexical entries for even very difficult or rare words can be established if these are defined when they are first introduced. However, little is known about the nature of the lexical representations children form for the words they encounter while listening to stories, or whether these are sufficiently robust to support the childâs own use of such âhigh-levelâ vocabulary. This study explored these questions by administering multiple assessments of childrenâs knowledge about a set of newly-acquired vocabulary. Four- and 6-year-old children were introduced to nine difficult new words (including nouns, verbs and adjectives) through three exposures to a story read by their class teacher. The story included a definition of each new word at its first encounter. Learning of the target vocabulary was assessed by means of two tests of semantic understanding â a forced choice picture-selection task and a definition production task â and a grammaticality judgment task, which asked children to choose between a syntactically-appropriate and syntactically-inappropriate usage of the word. Children in both age groups selected the correct pictorial representation and provided an appropriate definition for the target words in all three word classes significantly more often than they did for a matched set of non-exposed control words. However, only the older group was able to identify the syntactically-appropriate sentence frames in the grammaticality judgment task. Further analyses elucidate some of the components of the lexical representations children lay down when they hear difficult new vocabulary in stories and how different tests of word knowledge might overlap in their assessment of these components
From polygenic scores to precision medicine in Alzheimerâs Disease: A systematic review
Background: Late-onset Alzheimerâs Disease (AD) is highly heritable. The effect of many common genetic variants, single nucleotide polymorphisms (SNPs) confer risk. Variants are clustered in areas of biology, notably immunity and inflammation, cholesterol metabolism, endocytosis and ubiquitination. Polygenic scores (PRS), which weight the sum of an individualâs risk alleles, have been used to draw inferences about the pathological processes underpinning AD.
Objective: This paper aims to systematically review how AD PRS are being used to study a range of outcomes and phenotypes related to neurodegeneration.
Methods: We searched the literature from July 2008-July 2018 following PRISMA guidelines.
Results: 57 studies met criteria. The AD PRS can distinguish AD cases from controls. The ability of AD PRS to predict conversion from Mild Cognitive Impairment (MCI) to AD was less clear. There was strong evidence of association between AD PRS and cognitive impairment. AD PRS were correlated with a number of biological phenotypes associated with AD pathology, such as neuroimaging changes and amyloid and tau measures. Pathway-specific polygenic scores were also associated with AD-related biologically relevant phenotypes.
Conclusion: PRS can predict AD effectively and are associated with cognitive impairment. There is also evidence of association between AD PRS and other phenotypes relevant to neurodegeneration. The associations between pathway specific polygenic scores and phenotypic changes may allow us to define the biology of the disease in individuals and indicate who may benefit from specific treatments. Longitudinal cohort studies are required to test the ability of PGS to delineate pathway-specific disease activity
Quality control of earth construction in developing areas
Current quality control of earth construction in developing and disaster areas is very basic, relying on highly operator-dependent, non-standardised tests. The uncertainty in material properties has led to over-conservative design, increasing construction costs where it can least be afforded. The development of a quality control kit is described; to be fit for purpose it had to be cheap and easy to use. The equipment included had to be portable, resilient and independent of mains power. The hydrometer and Atterberg limit test methods from BS 1377 (soil investigation) are slightly modified to be more suitable for field application. The modified methods are deemed acceptable if they provide sufficient accuracy to be useful as a design tool. In an adaptation of cement mortar tests, the compressive strength of bricks or blocks is tested over a 100 mm Ă 100 mm area. This has been shown to give safe but not over-conservative values of strength using portable equipment. The report concludes that an accurate, quantitative kit can be compiled for under ÂŁ350 (US$560), excluding labour for its construction, with a mass of 10â25 kg, depending on the types of tests required. This is less than the mass of soil and blocks required for equivalent tests in a commercial laboratory. </jats:p
Assessing and monitoring intratumor heterogeneity in glioblastoma: how far has multimodal imaging come?
Glioblastoma demonstrates imaging features of intratumor heterogeneity that result from underlying heterogeneous biological properties. This stems from variations in cellular behavior that result from genetic mutations that either drive, or are driven by, heterogeneous microenvironment conditions. Among all imaging methods available, only T1-weighted contrast-enhancing and T2-weighted fluid-attenuated inversion recovery are used in standard clinical glioblastoma assessment and monitoring. Advanced imaging modalities are still considered emerging techniques as appropriate end points and robust methodologies are missing from clinical trials. Discovering how these images specifically relate to the underlying tumor biology may aid in improving quality of clinical trials and understanding the factors involved in regional responses to treatment, including variable drug uptake and effect of radiotherapy. Upon validation and standardization of emerging MR techniques, providing information based on the underlying tumor biology, these images may allow for clinical decision-making that is tailored to an individual's response to treatment.Stephen Price is funded by a Clinician Scientist Award from the National Institute for Health Research.This is the author accepted manuscript. The final version is available from Future Medicine via http://dx.doi.org/10.2217/cns.15.2
Girding the loins? Direct evidence of the use of a medieval English parchment birthing girdle from biomolecular analysis
In this paper, we describe palaeoproteomic evidence obtained from a stained medieval birth girdle using a previously developed dry non-invasive sampling technique. The parchment birth girdle studied (Wellcome Collection Western MS. 632) was made in England in the late fifteenth century and was thought to be used by pregnant women while giving birth. We were able to extract both human and non-human peptides from the manuscript, including evidence for the use of honey, cereals, ovicaprine milk and legumes. In addition, a large number of human peptides were detected on the birth roll, many of which are found in cervico-vaginal fluid. This suggests that the birth roll was actively used during childbirth. This study is, to our knowledge, the first to extract and analyse non-collagenous peptides from a birth girdle using this sampling method and demonstrates the potential of this type of analysis for stained manuscripts, providing direct biomolecular evidence for active use
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