585 research outputs found
Fundamental limits on inferring epidemic resurgence in real time using effective reproduction numbers
We find that epidemic resurgence, defined as an upswing in the effective reproduction number (R) of the contagion from subcritical to supercritical values, is fundamentally difficult to detect in real time. Inherent latencies in pathogen transmission, coupled with smaller and intrinsically noisier case incidence across periods of subcritical spread, mean that resurgence cannot be reliably detected without significant delays of the order of the generation time of the disease, even when case reporting is perfect. In contrast, epidemic suppression (where R falls from supercritical to subcritical values) may be ascertained 5–10 times faster due to the naturally larger incidence at which control actions are generally applied. We prove that these innate limits on detecting resurgence only worsen when spatial or demographic heterogeneities are incorporated. Consequently, we argue that resurgence is more effectively handled proactively, potentially at the expense of false alarms. Timely responses to recrudescent infections or emerging variants of concern are more likely to be possible when policy is informed by a greater quality and diversity of surveillance data than by further optimisation of the statistical models used to process routine outbreak data
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Electricity market design for the prosumer era
Prosumers are agents that both consume and produce energy. With the growth in small and medium-sized agents using solar photovoltaic panels, smart meters, vehicle-to-grid electric automobiles, home batteries and other ‘smart’ devices, prosuming offers the potential for consumers and vehicle owners to re-evaluate their energy practices. As the number of prosumers increases, the electric utility sector of today is likely to undergo significant changes over the coming decades, offering possibilities for greening of the system, but also bringing many unknowns and risks that need to be identified and managed. To develop strategies for the future, policymakers and planners need knowledge of how prosumers could be integrated effectively and efficiently into competitive electricity markets. Here we identify and discuss three promising potential prosumer markets related to prosumer grid integration, peer-to-peer models and prosumer community groups. We also caution against optimism by laying out a series of caveats and complexities
Photonic Crystal Nanobeam Cavity Strongly Coupled to the Feeding Waveguide
A deterministic design of an ultrahigh Q, wavelength scale mode volume
photonic crystal nanobeam cavity is proposed and experimentally demonstrated.
Using this approach, cavities with Q>10^6 and on-resonance transmission T>90%
are designed. The devices fabricated in Si and capped with low-index polymer,
have Q=80,000 and T=73%. This is, to the best of our knowledge, the highest
transmission measured in deterministically designed, wavelength scale high Q
cavities
Two Stroke High Efficient Gate Operated Magnetic Engine: Basis for Modeling Approach
The present report focuses on the fundamentals of modeling of a permanent magnet based gate operated repulsive magnetic piston engine further referred to as GOPI engine, applicable to electrical and mechanical power generation in large-scale system. In GOPI engine, the motion of the piston is controlled with help of a gate made up of magnetic shield material. The working of the engine depends upon magnetic and mechanical material properties of the gate like thickness of the gate, type of the shield material, distance of the gate from magnets, the pole strength of magnets and mechanism used to operate the gate. In GOPI engine the removal of complete mechanism of fuel burning process of the traditional engine gives a number of advantages like low frictional losses, reduced manufacturing cost, maintenance cost and compactness
Annotating Synapses in Large EM Datasets
Reconstructing neuronal circuits at the level of synapses is a central
problem in neuroscience and becoming a focus of the emerging field of
connectomics. To date, electron microscopy (EM) is the most proven technique
for identifying and quantifying synaptic connections. As advances in EM make
acquiring larger datasets possible, subsequent manual synapse identification
({\em i.e.}, proofreading) for deciphering a connectome becomes a major time
bottleneck. Here we introduce a large-scale, high-throughput, and
semi-automated methodology to efficiently identify synapses. We successfully
applied our methodology to the Drosophila medulla optic lobe, annotating many
more synapses than previous connectome efforts. Our approaches are extensible
and will make the often complicated process of synapse identification
accessible to a wider-community of potential proofreaders
Genome-wide expression profile of RNA polymerase II subunit mutant of yeast using microarray technology
Rpb4, the non-essential core subunit of RNA polymerase II has been assigned a function of regulating stress response in S. cerevisiae based mainly on phenotypes associated with its deletion. The actual mechanism has been elusive, although various hypotheses have been put forth. We have shown previously that it plays a significant role in activation of a subset of genes, rather than causing generalized defect in transcription. We used the microarray technology to look at the effect of this RNA polymerase subunit on the expression pattern of the entire S. cerevisiae genome. Many surprises emerged when we compared the genome-wide expression patterns of wild type and a mutant lacking the RPB4 gene (rpb4Δ) subjected to heat shock. The initial analysis of genes downregulated in the mutant showed that the co-regulation of genes is not position-dependent, although the locus carrying the deletion had unexpectedly a large cluster of down-regulated genes. We also found that among the known down-regulated genes, a majority is involved in hexose uptake and utilization. We speculate that this could potentially contribute to the slow growth rate of the mutant. Compared to the other components of the transcription machinery, the Rpb4 subunit affects a unique set of genes
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