4,156 research outputs found
DNA and pacific commensal models : applications, construction, limitations, and future prospects
Components of the Pacific transported landscape have been used as proxies to trace the prehistoric movement of humans across the Pacific for almost two decades. Analyses of archaeological remains and DNA sequences of plants, animals, and microorganisms moved by or with humans have contributed to understanding prehistoric migration, trade, exchange, and sometimes revealed the geographic origins of particular plants and animals. This paper presents the basic elements of a DNA-based commensal model and discusses the phylogenetic and population genetic approaches these models employ. A clear delineation of the underlying assumptions of these models and the background information required to construct them have yet to appear in the literature. This not only provides a framework with which to construct a commensal model but also highlights gaps in current knowledge. The ways in which commensal models have enriched archaeological reconstructions will be highlighted, as will their current limitations. With these limitations in mind, options will be outlined for augmenting commensal models through the application of established techniques and new technologies in order to provide the best tools for reconstructing ancient human mobility and behavior in the Pacific and beyond
Optimization of a Fast-Pick Area in a Cosmetics Distribution Center
Fast-pick areas are commonly used in order picking warehouses to improve labor efficiency by concentrating picking activities within a compact area, thus minimizing the distance traveled by the pickers. One problem that must be solved when a fast-pick area is to be implemented is the so-called assignment-allocation problem. This deals with deciding which products should be assigned to the fast-pick area, and how much space should be allocated to these products. This research was motivated by the picking operation of a cosmetics distribution center where several fast-pick areas are in place. A mixed integer linear programming formulation is proposed for solving the variant of the assignment-allocation problem found in this company. Our computational experiments show that the proposed model is efficient for solving small yet realistic instances of the problem
An Extended Double Row Layout Problem
The double row layout problem (DRLP) seeks to determine optimal machine locations on either side of an aisle, where the objective has been defined as the minimization of material ow cost among ma- chines while meeting machine clearance constraints. In this paper, we extend existing DRLP formulations in two respects. First, we consider the minimization of layout area besides the usual material ow cost objective. Second, we present a mixed integer linear programming formulation that permits non-zero aisle widths. This new formulation also includes new constraints that eliminate layout \mirroring, thus reducing the solution space significantly and thus solution times. Although small-scale problems may be solved optimally by commercial integer programming solvers, solution times are highly sensitive to the number of machines in a layout. A tabu search heuristic is shown to work well for moderately-sized problems. Numerical examples demonstrating the impact of both ow and area objectives, as well as aisle widths, are included
Effects of exercise and sport in solid organ transplant recipients: a review
Solid organ transplantation is the gold-standard treatment for many with end-organ failure and can offer a new independence from the burden of disease. However solid organ transplant recipients (SOTRs) remain at high risk of cardiovascular disease (CVD), poor quality of life and physical functioning. Increasing physical activity and exercise can improve the health of the general population, however the effects on those with a transplant remain unclear. Intensive exercise and sporting activity has the potential to be beneficial, although there remain concerns particularly around the effects on immune function and the CV system. This review summarises what is known about the effects of exercise on determinants of health in SOTR and then collates the available literature investigating the consequences of intensive exercise and sport on the health of SOTR. There is a paucity of high-quality research, with most evidence being case-studies or anecdotal; this is understandable given the relatively few numbers of SOTR who are performing sport and exercise at a high level. However if suitable evidence-based guidelines are to be formed and SOTR are to be given reassurances that their activity levels are not detrimental to their transplanted organ and overall health, then more high-quality studies are required
The Impact of Exercising During Haemodialysis on Blood Pressure, Markers of Cardiac Injury and Systemic Inflammation - Preliminary Results of a Pilot Study
This article is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
License (CC BY-NC-ND) (http://www.karger.com/Services/OpenAccessLicense). Usage and distribution
for commercial purposes as well as any distribution of modified material requires written permission.Background/Aims: Patients requiring haemodialysis have cardiovascular and immune
dysfunction. Little is known about the acute effects of exercise during haemodialysis. Exercise
has numerous health benefits but in other populations has a profound impact upon blood
pressure, inflammation and immune function; therefore having the potential to exacerbate
cardiovascular and immune dysfunction in this vulnerable population. Methods: Fifteen
patients took part in a randomised-crossover study investigating the effect of a 30-min
bout of exercise during haemodialysis compared to resting haemodialysis. We assessed
blood pressure, plasma markers of cardiac injury and systemic inflammation and neutrophil
degranulation. Results: Exercise increased blood pressure immediately post-exercise; however,
1 hour after exercise blood pressure was lower than resting levels (106±22 vs. 117±25 mm
Hg). No differences in h-FABP, cTnI, myoglobin or CKMB were observed between trial arms.
Exercise did not alter circulating concentrations of IL-6, TNF-α or IL-1ra nor clearly suppress
neutrophil function. Conclusions: This study demonstrates fluctuations in blood pressure
during haemodialysis in response to exercise. However, since the fall in blood pressure
occurred without evidence of cardiac injury, we regard it as a normal response to exercise
superimposed onto the haemodynamic response to haemodialysis. Importantly, exercise did
not exacerbate systemic inflammation or immune dysfunction; intradialytic exercise was well
tolerated
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Psychometric properties of the Stroke and Aphasia Quality of Life Scale (SAQOL-39) in a generic stroke population
Background: We previously developed the Stroke and Aphasia Quality of Life scale (SAQOL-39) and tested it with people with chronic aphasia. A scale allowing comparisons of quality of life between people with versus without aphasia post-stroke would be of value to clinicians.
Objectives: To evaluate the psychometrics of the SAQOL-39 in a generic stroke sample. Should this process result in a generic-stroke version of the scale (SAQOL-39g), a further aim is to compare the latter and the SAQOL-39 as tested in chronic aphasia.
Design and subjects: Repeated measures psychometric study, evaluating internal consistency, test—retest reliability, construct validity and responsiveness to change. People admitted to hospital with a first stroke were assessed two weeks, three months and six months post stroke.
Measures: SAQOL-39, National Institutes of Health Stroke Scale, Barthel, Frenchay Aphasia Screening Test, General Health Questionnaire-12 and Frenchay Activities Index.
Results: Of 126 eligible participants, 96 (76%) participated and 87 (69%) were able to self-report and are presented here. Testing the SAQOL-39 in generic stroke resulted in the SAQOL-39g, which has the same items as the SAQOL-39 but three domains: physical, psychosocial, communication. The SAQOL-39g showed good internal consistency (α = 0.95 overall score, 0.92—0.95 domains), test—retest reliability (interclass correlation (ICC) = 0.96 overall, 0.92—0.98 domains), convergent (r = 0.36—0.70 overall, 0.47—0.78 domains) and discriminant validity (r = 0.26 overall, 0.03—0.40 domains). It differentiated people by stroke severity and visual analogue scale (VAS)-defined quality of life. Moderate changes (d = 0.35—0.49; standardized response mean (SRM) = 0.29—0.53) from two weeks to six months supported responsiveness.
Conclusions: The SAQOL-39g demonstrated good reliability, validity and responsiveness to change. It can be used to evaluate quality of life in people with and without aphasia post stroke
Discovery of a 500 pc shell in the nucleus of Centaurus A
Spitzer Space Telescope mid-infrared images of the radio galaxy Centaurus A
reveal a shell-like, bipolar, structure 500 pc to the north and south of the
nucleus. This shell is seen in 5.8, 8.0 and 24 micron broad-band images. Such a
remarkable shell has not been previously detected in a radio galaxy and is the
first extragalactic nuclear shell detected at mid-infrared wavelengths. We
estimate that the shell is a few million years old and has a mass of order
million solar masses. A conservative estimate for the mechanical energy in the
wind driven bubble is 10^53 erg. The shell could have created by a small few
thousand solar mass nuclear burst of star formation. Alternatively, the
bolometric luminosity of the active nucleus is sufficiently large that it could
power the shell. Constraints on the shell's velocity are lacking. However, if
the shell is moving at 1000 km/s then the required mechanical energy would be
100 times larger.Comment: submitted to ApJ Letter
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