1,064 research outputs found
Recommended from our members
Governance Indicators Can Make Sense: Under-five Mortality Rates are an Example
Governance indicators have come under fire in recent years, especially the World Governance Indicators (WGIs). Critics present these indicators as a-theoretical and biased. Critics of the critics counter that no better alternatives exist. We suggest otherwise, arguing that more appropriate ‘governance’ indicators will (i) have theoretical grounding, (ii) focus on specific fields of engagement, (iii) emphasize outcomes, and (iv) control for key contextual differences in comparing countries. Such measures can help indicate where countries seem to have governance problems, allowing second stage analyses of what these problems are. We present under national five mortality rates adjusted for country income groups as an example of such measure, presenting data for contextually controlled outcomes in this specific field to show where governance seems better and worse. The United States is shown up as relatively weak, whereas a country like Pakistan seems to have better governance in this sector than other low income countries. The indicator allows questions about why governance of this sector might be problematic in certain contexts and easier in others
Spin transfer switching of spin valve nanopillars using nanosecond pulsed currents
Spin valve nanopillars are reversed via the mechanism of spin momentum
transfer using current pulses applied perpendicular to the film plane of the
device. The applied pulses were varied in amplitude from 1.8 mA to 7.8 mA, and
varied in duration within the range of 100 ps to 200 ns. The probability of
device reversal is measured as a function of the pulse duration for each pulse
amplitude. The reciprocal pulse duration required for 95% reversal probability
is linearly related to the pulse current amplitude for currents exceeding 1.9
mA. For this device, 1.9 mA marks the crossover between dynamic reversal at
larger currents and reversal by thermal activation for smaller currents
In-vitro measurement of high peak fluid pressure gradients across prosthetic heart valves at closing
Asymptotic reduction of a porous electrode model for lithium-ion batteries
We present a porous electrode model for lithium-ion batteries using
Butler--Volmer reaction kinetics. We model lithium concentration in both the
solid and fluid phase along with solid and liquid electric potential. Through
asymptotic reduction, we show that the electric potentials are spatially
homogeneous which decouples the problem into a series of time-dependent
problems. These problems can be solved on three distinguished time scales, an
early time scale where capacitance effects in the electrode dominate, a
mid-range time scale where a spatial concentration gradient forms in the
electrolyte, and a long-time scale where each of the electrodes saturate and
deplete with lithium respectively. The solid-phase concentration profiles are
linear functions of time and the electrolyte potential is everywhere zero,
which allows the model to be reduced to a system of two uncoupled ordinary
differential equations. Analytic and numerical results are compared with full
numerical simulations and experimental discharge curves demonstrating excellent
agreement.Comment: Accepted in SIAM Journal on Applied Mathematic
Legislative Reform
This session addresses the issues of bias that are currently present in both the federal and state legislatures, namely the problems of antidemocratic internal rules, personal or staff conflicts of interest, secrecy in deals struck, and information imbalance favoring special, organized interest
Experimental simulation of closed timelike curves
Closed timelike curves are among the most controversial features of modern physics. As legitimate solutions to Einstein's field equations, they allow for time travel, which instinctively seems paradoxical. However, in the quantum regime these paradoxes can be resolved, leaving closed timelike curves consistent with relativity. The study of these systems therefore provides valuable insight into nonlinearities and the emergence of causal structures in quantum mechanics-essential for any formulation of a quantum theory of gravity. Here we experimentally simulate the nonlinear behaviour of a qubit interacting unitarily with an older version of itself, addressing some of the fascinating effects that arise in systems traversing a closed timelike curve. These include perfect discrimination of non-orthogonal states and, most intriguingly, the ability to distinguish nominally equivalent ways of preparing pure quantum states. Finally, we examine the dependence of these effects on the initial qubit state, the form of the unitary interaction and the influence of decoherence
Finding function: evaluation methods for functional genomic data
BACKGROUND: Accurate evaluation of the quality of genomic or proteomic data and computational methods is vital to our ability to use them for formulating novel biological hypotheses and directing further experiments. There is currently no standard approach to evaluation in functional genomics. Our analysis of existing approaches shows that they are inconsistent and contain substantial functional biases that render the resulting evaluations misleading both quantitatively and qualitatively. These problems make it essentially impossible to compare computational methods or large-scale experimental datasets and also result in conclusions that generalize poorly in most biological applications. RESULTS: We reveal issues with current evaluation methods here and suggest new approaches to evaluation that facilitate accurate and representative characterization of genomic methods and data. Specifically, we describe a functional genomics gold standard based on curation by expert biologists and demonstrate its use as an effective means of evaluation of genomic approaches. Our evaluation framework and gold standard are freely available to the community through our website. CONCLUSION: Proper methods for evaluating genomic data and computational approaches will determine how much we, as a community, are able to learn from the wealth of available data. We propose one possible solution to this problem here but emphasize that this topic warrants broader community discussion
The effect of sex, menstrual cycle phase and oral contraceptive use on intestinal permeability and ex-vivo monocyte TNFα release following treatment with lipopolysaccharide and hyperthermia
Investigate the impact of sex, menstrual cycle phase and oral contraceptive use on intestinal permeability and ex-vivo tumour necrosis factor alpha (TNFα) release following treatment with lipopolysaccharide (LPS) and hyperthermia. Twenty-seven participants (9 men, 9 eumenorrheic women (MC) and 9 women taking an oral contraceptive pill (OC)) completed three trials. Men were tested on 3 occasions over 6 weeks; MC during early-follicular, ovulation, and mid-luteal phases; OC during the pill and pill-free phase. Intestinal permeability was assessed following a 4-hour dual sugar absorption test (lactulose: rhamnose). Venous blood was collected each trial and stimulated with 100 μg·mL LPS before incubation at 37 °C and 40 °C and analysed for TNFα via ELISA. L:R ratio was higher in OC than MC (+0.003, p = 0.061) and men (+0.005, p = 0.007). Men had higher TNFα responses than both MC (+53 %, p = 0.004) and OC (+61 %, p = 0.003). TNFα release was greater at 40 °C than 37 °C (+23 %, p < 0.001). Men present with lower resting intestinal barrier permeability relative to women regardless of OC use and displayed greater monocyte TNFα release following whole blood treatment with LPS and hyperthermia. Oral contraceptive users had highest intestinal permeability however, neither permeability or TNFα release were impacted by the pill cycle. Although no statistical effect was seen in the menstrual cycle, intestinal permeability and TNFα release were more variable across the phases
The Molecular Pathogenesis of Osteosarcoma: A Review
Osteosarcoma is the most common primary malignancy of bone. It arises in bone during periods of rapid growth and primarily affects adolescents and young adults. The 5-year survival rate for osteosarcoma is 60%–70%, with no significant improvements in prognosis since the advent of multiagent chemotherapy. Diagnosis, staging, and surgical management of osteosarcoma remain focused on our anatomical understanding of the disease. As our knowledge of the molecular pathogenesis of osteosarcoma expands, potential therapeutic targets are being identified. A comprehensive understanding of these mechanisms is essential if we are to improve the prognosis of patients with osteosarcoma through tumour-targeted therapies. This paper will outline the pathogenic mechanisms of osteosarcoma oncogenesis and progression and will discuss some of the more frontline translational studies performed to date in search of novel, safer, and more targeted drugs for disease management
- …