2,803 research outputs found
A feasibility study: California Department of Forestry and Fire Protection utilization of infrared technologies for wildland fire suppression and management
NASA's JPL has completed a feasibility study using infrared technologies for wildland fire suppression and management. The study surveyed user needs, examined available technologies, matched the user needs with technologies, and defined an integrated infrared wildland fire mapping concept system configuration. System component trade-offs were presented for evaluation in the concept system configuration. The economic benefits of using infrared technologies in fire suppression and management were examined. Follow-on concept system configuration development and implementation were proposed
Transplantation of progenitor cells and regeneration enhancement in acute myocardial infarction - (TOPCARE-AMI)
Background - Experimental studies suggest that transplantation of blood-derived or bone marrow–derived progenitor cells beneficially affects postinfarction remodeling. The safety and feasibility of autologous progenitor cell transplantation in patients with ischemic heart disease is unknown
Timescales of spike-train correlation for neural oscillators with common drive
We examine the effect of the phase-resetting curve (PRC) on the transfer of
correlated input signals into correlated output spikes in a class of neural
models receiving noisy, super-threshold stimulation. We use linear response
theory to approximate the spike correlation coefficient in terms of moments of
the associated exit time problem, and contrast the results for Type I vs. Type
II models and across the different timescales over which spike correlations can
be assessed. We find that, on long timescales, Type I oscillators transfer
correlations much more efficiently than Type II oscillators. On short
timescales this trend reverses, with the relative efficiency switching at a
timescale that depends on the mean and standard deviation of input currents.
This switch occurs over timescales that could be exploited by downstream
circuits
Climate Change and the Integrity of Science
We are deeply disturbed by the recent escalation of political assaults on scientists in general and on climate scientists in particular. All citizens should understand some basic scientific facts. There is always some uncertainty associated with scientific conclusions; science
never absolutely proves anything. When someone says that society should wait until scientists are absolutely certain before taking any action, it is the same as saying society should never take action. For a problem as potentially catastrophic as climate change, taking no action poses
a dangerous risk for our planet
Speed and Accuracy of Static Image Discrimination by Rats
When discriminating dynamic noisy sensory signals, human and primate subjects
achieve higher accuracy when they take more time to decide, an effect
attributed to accumulation of evidence over time to overcome neural noise. We
measured the speed and accuracy of twelve freely behaving rats discriminating
static, high contrast photographs of real-world objects for water reward in a
self-paced task. Response latency was longer in correct trials compared to
error trials. Discrimination accuracy increased with response latency over the
range of 500-1200ms. We used morphs between previously learned images to vary
the image similarity parametrically, and thereby modulate task difficulty from
ceiling to chance. Over this range we find that rats take more time before
responding in trials with more similar stimuli. We conclude that rats'
perceptual decisions improve with time even in the absence of temporal
information in the stimulus, and that rats modulate speed in response to
discrimination difficulty to balance speed and accuracy
A multimerizing transcription factor of sea urchin embryos capable of looping DNA
SpGCF1 is a recently cloned sea urchin transcription factor that recognizes target sites in several different sea urchin genes. We find that in gel-shift experiments this factor is able to multimerize. A quantitative simulation of the gel-shift results suggests that SpGCF1 molecules that are bound to DNA target sites may also bind to one another, thus associating several DNA probe molecules. SpGCF1 might therefore be able to loop DNA molecules bearing its target sites at distant locations. We demonstrate this prediction by electron microscopy, and using the well-characterized cis-regulatory domain of the CyIIIa cytoskeletal actin gene, we show that the loop conformations predicted from the known SpGCF1 target site locations are actually formed in vitro. We speculate that the multimerization of this factor in vivo may function to bring distant regions of extended regulatory domains into immediate proximity so that they can interact with one another
Classical phase transitions in a one-dimensional short-range spin model
Ising's solution of a classical spin model famously demonstrated the absence
of a positive-temperature phase transition in one-dimensional equilibrium
systems with short-range interactions. No-go arguments established that the
energy cost to insert domain walls in such systems is outweighed by entropy
excess so that symmetry cannot be spontaneously broken. An archetypal way
around the no-go theorems is to augment interaction energy by increasing the
range of interaction. Here we introduce new ways around the no-go theorems by
investigating entropy depletion instead. We implement this for the Potts model
with invisible states.Because spins in such a state do not interact with their
surroundings, they contribute to the entropy but not the interaction energy of
the system. Reducing the number of invisible states to a negative value
decreases the entropy by an amount sufficient to induce a positive-temperature
classical phase transition. This approach is complementary to the long-range
interaction mechanism. Alternatively, subjecting positive numbers of invisible
states to imaginary or complex fields can trigger such a phase transition. We
also discuss potential physical realisability of such systems.Comment: 29 pages, 11 figure
The promoter polymorphism -232C/G of the PCK1 gene is associated with type 2 diabetes in a UK-resident South Asian population
Background: The PCK1 gene, encoding cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C), has previously been implicated as a candidate gene for type 2 diabetes (T2D) susceptibility. Rodent models demonstrate that over-expression of Pck1 can result in T2D development and a single nucleotide polymorphism (SNP) in the promoter region of human PCK1 (-232C/G) has exhibited significant association with the disease in several cohorts. Within the UK-resident South Asian population, T2D is 4 to 6 times more common than in indigenous white Caucasians. Despite this, few studies have reported on the genetic susceptibility to T2D in this ethnic group and none of these has investigated the possible effect of PCK1 variants. We therefore aimed to investigate the association between common variants of the PCK1 gene and T2D in a UK-resident South Asian population of Punjabi ancestry, originating predominantly from the Mirpur area of Azad Kashmir, Pakistan. \ud
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Methods: We used TaqMan assays to genotype five tagSNPs covering the PCK1 gene, including the -232C/G variant, in 903 subjects with T2D and 471 normoglycaemic controls. \ud
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Results: Of the variants studied, only the minor allele (G) of the -232C/G SNP demonstrated a significant association with T2D, displaying an OR of 1.21 (95% CI: 1.03 - 1.42, p = 0.019). \ud
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Conclusion: This study is the first to investigate the association between variants of the PCK1 gene and T2D in South Asians. Our results suggest that the -232C/G promoter polymorphism confers susceptibility to T2D in this ethnic group. \ud
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Trial registration: UKADS Trial Registration: ISRCTN38297969
Delineation of individual human chromosomes in metaphase and interphase cells by in situ suppression hybridization using recombinant DNA libraries
A method of in situ hybridization for visualizing individual human chromosomes from pter to qter, both in metaphase spreads and interphase nuclei, is reported. DNA inserts from a single chromosomal library are labeled with biotin and partially preannealed with a titrated amount of total human genomic DNA prior to hybridization with cellular or chromosomal preparations. The cross-hybridization of repetitive sequences to nontargeted chromosomes can be markedly suppressed under appropriate preannealing conditions. The remaining single-stranded DNA is hybridized to specimens of interest and detected with fluorescent or enzymelabeled avidin conjugates following post-hybridization washes. DNA inserts from recombinant libraries for chromosomes 1, 4, 7, 8, 13, 14, 18, 20, 21, 22, and X were assessed for their ability to decorate specifically their cognate chromosome; most libraries proved to be highly specific. Quantitative densitometric analyses indicated that the ratio of specific to nonspecific hybridization signal under optimal preannealing conditions was at least 8:1. Interphase nuclei showed a cohesive territorial organization of chromosomal domains, and laserscanning confocal fluorescence microscopy was used to aid the 3-D visualization of these domains. This method should be useful for both karyotypic studies and for the analysis of chromosome topography in interphase cells
Prevention is better than cure, but...: Preventive medication as a risk to ordinariness?
Preventive health remains at the forefront of public health concerns; recent initiatives, such as the NHS health check, may lead to recommendations for medication in response to the identification of 'at risk' individuals. Little is known about lay views of preventive medication. This paper uses the case of aspirin as a prophylactic against heart disease to explore views among people invited to screening for a trial investigating the efficacy of such an approach. Qualitative interviews (N=46) and focus groups (N=5, participants 31) revealed dilemmas about preventive medication in the form of clashes between norms: first, in general terms, assumptions about the benefit of prevention were complicated by dislike of medication; second, the individual duty to engage in prevention was complicated by the need not to be over involved with one's own health; third, the potential appeal of this alternative approach to health promotion was complicated by unease about the implications of encouraging irresponsible behaviour among others. Though respondents made different decisions about using the drug, they reported very similar ways of trying to resolve these conflicts, drawing upon concepts of necessity and legitimisation and the special ordinariness of the particular dru
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