743 research outputs found
Interdependence: An Alternative Conceptualization
Conceptualizations of interdependence offered by Thompson (1967) and McCann and Ferry (1979) fail to satisfy basic requirements for empirical or practical investigations of complex organizations. An alternative conceptualization based on interdependence theory (Kelley & Thibaut, 1978; Thibaut & Kelley, 1959) is presented here and used to explain the causes of interunit conflict and the effective- ness of coordination strategy. Hypotheses are presented, and future research is proposed
Beltway: Getting Around Garbage Collection Gridlock
We present the design and implementation of a new garbage collection framework that significantly generalizes existing copying collectors. The Beltway framework exploits and separates object age and incrementality. It groups objects in one or more increments on queues called belts, collects belts independently, and collects increments on a belt in first-in-first-out order. We show that Beltway configurations, selected by command line options, act and perform the same as semi-space, generational, and older-first collectors, and encompass all previous copying collectors of which we are aware. The increasing reliance on garbage collected languages such as Java requires that the collector perform well. We show that the generality of Beltway enables us to design and implement new collectors that are robust to variations in heap size and improve total execution time over the best generational copying collectors of which we are aware by up to 40%, and on average by 5 to 10%, for small to moderate heap sizes. New garbage collection algorithms are rare, and yet we define not just one, but a new family of collectors that subsumes previous work. This generality enables us to explore a larger design space and build better collectors
Enrichment of cellulose acetate nanofibre assemblies for therapeutic delivery of L-tryptophan
The essential amino acid L-tryptophan is naturally present in the body, and is also available as a water soluble dietary supplement. The feasibility of preparing enriched cellulose acetate (CA)-based fibres as a vehicle for therapeutic delivery of such biomolecules was investigated. A new ternary solvent system consisting of acetone: N,N-dimethylacetamide: methanol (2:1:2) has been demonstrated to permit the solution blending of CA with the water soluble L-tryptophan. Nanofibrous webs substantially free of structural defects were continuously produced with mean fibre diameters in the range of 520-1,010nm, dependent on process parameters. Morphology and diameter of fibres were influenced by concentration of CA spinning solution, applied voltage and flow rates. The kinetic release profile of L-tryptophan from electrospun CA nanofibres was described by the pseudo-second order kinetic model. Fibres with mean diameter of 720 nm provide both the highest initial desorption rate and rate constant, which was partially attributed to the low fibre diameter and high relative surface area, but also the fact that the fibres with mean diameter of 720 nm produced were the most bead-free, providing diffusion advantages over the fibres with lowest mean diameter (520 nm). The feasibility of combining L-tryptophan within fibres provides a promising route for manufacture of transdermal delivery devices
The rate of leukocyte telomere shortening predicts mortality from cardiovascular disease in elderly men
Telomere length (TL) has been proposed as a marker of
mitotic cell age and as a general index of human organismic aging. Short
absolute leukocyte telomere length has been linked to
cardiovascular-related morbidity and mortality. Our aim was to test
whether the rate of change in leukocyte TL is related to mortality in a
healthy elderly cohort. We examined a subsample of 236 randomly selected
Caucasian participants from the MacArthur Health Aging Study (aged 70 to 79
years). DNA samples from baseline and 2.5 years later were assayed for
mean TL of leukocytes. Percent change in TL was calculated as a measure of
TL change (TLC). Associations between TL and TLC with 12-year overall and
cardiovascular mortality were assessed. Over the 2.5 year period, 46% of
the study participants showed maintenance of mean bulk TL, whereas 30%
showed telomere shortening, and, unexpectedly, 24% showed telomere
lengthening. For women, short baseline TL was related to greater mortality
from cardiovascular disease (OR = 2.3; 95% CI: 1.0 - 5.3). For men, TLC
(specifically shortening), but not baseline TL, was related to greater
cardiovascular mortality, OR = 3.0 (95% CI: 1.1 - 8.2). This is the first
demonstration that rate of telomere length change (TLC) predicts mortality
and thus may be a useful prognostic factor for longevity
Optimizing the colour and fabric of targets for the control of the tsetse fly Glossina fuscipes fuscipes
Background:
Most cases of human African trypanosomiasis (HAT) start with a bite from one of the subspecies of Glossina fuscipes. Tsetse use a range of olfactory and visual stimuli to locate their hosts and this response can be exploited to lure tsetse to insecticide-treated targets thereby reducing transmission. To provide a rational basis for cost-effective designs of target, we undertook studies to identify the optimal target colour.
Methodology/Principal Findings:
On the Chamaunga islands of Lake Victoria , Kenya, studies were made of the numbers of G. fuscipes fuscipes attracted to targets consisting of a panel (25 cm square) of various coloured fabrics flanked by a panel (also 25 cm square) of fine black netting. Both panels were covered with an electrocuting grid to catch tsetse as they contacted the target. The reflectances of the 37 different-coloured cloth panels utilised in the study were measured spectrophotometrically. Catch was positively correlated with percentage reflectance at the blue (460 nm) wavelength and negatively correlated with reflectance at UV (360 nm) and green (520 nm) wavelengths. The best target was subjectively blue, with percentage reflectances of 3%, 29%, and 20% at 360 nm, 460 nm and 520 nm respectively. The worst target was also, subjectively, blue, but with high reflectances at UV (35% reflectance at 360 nm) wavelengths as well as blue (36% reflectance at 460 nm); the best low UV-reflecting blue caught 3× more tsetse than the high UV-reflecting blue.
Conclusions/Significance:
Insecticide-treated targets to control G. f. fuscipes should be blue with low reflectance in both the UV and green bands of the spectrum. Targets that are subjectively blue will perform poorly if they also reflect UV strongly. The selection of fabrics for targets should be guided by spectral analysis of the cloth across both the spectrum visible to humans and the UV region
Challenging perceptions of fast and slow in contemporary fashion: A review of the paper dresses trend in the United Kingdom and the United States during the 1960s
Writing in 2022 we are at a global crisis point, as our use of the planet’s finite resources outstrips supply. Our current lifestyles continue to perpetuate this problem by encouraging excessive and wasteful models of consumption. One of the most detrimental industries for this is the clothing industry. Our fashion cycle is now programmed to be ‘ultra-fast’, encouraging excessive consumption of garments causing myriad environmental issues. This article argues that there are developing models of both manufacture and consumption, which can satiate this need for ‘fast’ fashion whilst being part of the wider sustainable fashion conversation. Rather than understanding the short-term life cycle of clothing as inherently unsustainable, this can be reframed as matching a garment’s use phase to the longevity of the material it is made from. This article uses a material culture approach to explore original 1960s paper garments, alongside a critical analysis of the sustainability of their manufacture and disposal from a green chemical perspective. Using the combined knowledge and experience of its authors, from historians and sustainable fashion designers to green chemists and biochemical engineers, this article demonstrates how such garments could inspire new models of sustainable fashion production and consumption. We argue that the current paradigm of slow fashion as the only antidote to fast fashion must be challenged. Instead, the fashion and textile sector must consider a range of solutions to the environmental burden of fast fashion that are human-centred and sympathetic to all consumer demographics and needs
Science and Ideology in Economic, Political, and Social Thought
This paper has two sources: One is my own research in three broad areas: business cycles, economic measurement and social choice. In all of these fields I attempted to apply the basic precepts of the scientific method as it is understood in the natural sciences. I found that my effort at using natural science methods in economics was met with little understanding and often considerable hostility. I found economics to be driven less by common sense and empirical evidence, then by various ideologies that exhibited either a political or a methodological bias, or both. This brings me to the second source: Several books have appeared recently that describe in historical terms the ideological forces that have shaped either the direct areas in which I worked, or a broader background. These books taught me that the ideological forces in the social sciences are even stronger than I imagined on the basis of my own experiences.
The scientific method is the antipode to ideology. I feel that the scientific work that I have done on specific, long standing and fundamental problems in economics and political science have given me additional insights into the destructive role of ideology beyond the history of thought orientation of the works I will be discussing
Cumulative Inflammatory Load Is Associated with Short Leukocyte Telomere Length in the Health, Aging and Body Composition Study
Background: Leukocyte telomere length (LTL) is an emerging marker of biological age. Chronic inflammatory activity is commonly proposed as a promoter of biological aging in general, and of leukocyte telomere shortening in particular. In addition, senescent cells with critically short telomeres produce pro-inflammatory factors. However, in spite of the proposed causal links between inflammatory activity and LTL, there is little clinical evidence in support of their covariation and interaction. Methodology/Principal Findings: To address this issue, we examined if individuals with high levels of the systemic inflammatory markers interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and C-reactive protein (CRP) had increased odds for short LTL. Our sample included 1,962 high-functioning adults who participated in the Health, Aging and Body Composition Study (age range: 70-79 years). Logistic regression analyses indicated that individuals with high levels of either IL-6 or TNF-α had significantly higher odds for short LTL. Furthermore, individuals with high levels of both IL-6 and TNF-α had significantly higher odds for short LTL compared with those who had neither high (OR = 0.52, CI = 0.37-0.72), only IL-6 high (OR = 0.57, CI = 0.39-0.83) or only TNF-α high (OR = 0.67, CI = 0.46-0.99), adjusting for a wide variety of established risk factors and potential confounds. In contrast, CRP was not associated with LTL. Conclusions/Significance: Results suggest that cumulative inflammatory load, as indexed by the combination of high levels of IL-6 and TNF-α, is associated with increased odds for short LTL. In contrast, high levels of CRP were not accompanied by short LTL in this cohort of older adults. These data provide the first large-scale demonstration of links between inflammatory markers and LTL in an older population
Publishing and sharing multi-dimensional image data with OMERO
Imaging data are used in the life and biomedical sciences to measure the molecular and structural composition and dynamics of cells, tissues, and organisms. Datasets range in size from megabytes to terabytes and usually contain a combination of binary pixel data and metadata that describe the acquisition process and any derived results. The OMERO image data management platform allows users to securely share image datasets according to specific permissions levels: data can be held privately, shared with a set of colleagues, or made available via a public URL. Users control access by assigning data to specific Groups with defined membership and access rights. OMERO’s Permission system supports simple data sharing in a lab, collaborative data analysis, and even teaching environments. OMERO software is open source and released by the OME Consortium at www.openmicroscopy.org
Do agri-environment schemes result in improved water quality?
Welsh Government. Grant Number: 183/2007/0
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