6,928 research outputs found
Optimal control of hepatitis C antiviral treatment programme delivery for prevention amongst a population of injecting drug users.
In most developed countries, HCV is primarily transmitted by injecting drug users (IDUs). HCV antiviral treatment is effective, and deemed cost-effective for those with no re-infection risk. However, few active IDUs are currently treated. Previous modelling studies have shown antiviral treatment for active IDUs could reduce HCV prevalence, and there is emerging interest in developing targeted IDU treatment programmes. However, the optimal timing and scale-up of treatment is unknown, given the real-world constraints commonly existing for health programmes. We explore how the optimal programme is affected by a variety of policy objectives, budget constraints, and prevalence settings. We develop a model of HCV transmission and treatment amongst active IDUs, determine the optimal treatment programme strategy over 10 years for two baseline chronic HCV prevalence scenarios (30% and 45%), a range of maximum annual budgets (ÂŁ50,000-300,000 per 1,000 IDUs), and a variety of objectives: minimising health service costs and health utility losses; minimising prevalence at 10 years; minimising health service costs and health utility losses with a final time prevalence target; minimising health service costs with a final time prevalence target but neglecting health utility losses. The largest programme allowed for a given budget is the programme which minimises both prevalence at 10 years, and HCV health utility loss and heath service costs, with higher budgets resulting in greater cost-effectiveness (measured by cost per QALY gained compared to no treatment). However, if the objective is to achieve a 20% relative prevalence reduction at 10 years, while minimising both health service costs and losses in health utility, the optimal treatment strategy is an immediate expansion of coverage over 5-8 years, and is less cost-effective. By contrast, if the objective is only to minimise costs to the health service while attaining the 20% prevalence reduction, the programme is deferred until the final years of the decade, and is the least cost-effective of the scenarios
Attractive plant volatiles as a control method against apple fruit moth (Argyresthia conjugella Zell.)?
Apple fruit moth, Argyresthia conjugella Zell. (Lepidoptera: Argyresthiidae), is the most important
pest of apples in Scandinavia. In years when its primary host, rowan (Sorbus aucuparia L.), has little
or no berries for egglaying, female A. conjugella fly into apple orchards to lay their eggs. In some
years the entire apple crop can be destroyed. Volatiles from apples and rowan have been collected
and identified. In GC-EAD tests females have responded to several compounds found in both
rowan and apple. Some of these compounds were used in field trapping tests during 2002, and a
mixture of two compounds trapped significantly more females and males compared to control traps.
However, field trapping results from 2003 indicate that the two-compound blend seem to trap insects
too late in the season to prevent egglaying in apples. Several new compounds were also
tested in 2003, and some of these gave promising results. The results will be discussed in relation
to use attractive plant volatiles as a control method against A. conjugella females
Estimation of historical groundwater contaminant distribution using the adjoint state method applied to geostatistical inverse modeling
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95609/1/wrcr10022.pd
Rectifiable paths with polynomial log-signature are straight lines
The signature of a rectifiable path is a tensor series in the tensor algebra
whose coefficients are definite iterated integrals of the path. The signature
characterises the path up to a generalised form of reparametrisation. It is a
classical result of K. T. Chen that the log-signature (the logarithm of the
signature) is a Lie series. A Lie series is polynomial if it has finite degree.
We show that the log-signature is polynomial if and only if the path is a
straight line up to reparametrisation. Consequently, the log-signature of a
rectifiable path either has degree one or infinite support. Though our result
pertains to rectifiable paths, the proof uses results from rough path theory,
in particular that the signature characterises a rough path up to
reparametrisation.Comment: 11 page
Extreme star formation events in quasar hosts over
We explore the relationship between active galactic nuclei and star formation
in a sample of 513 optically luminous type 1 quasars up to redshifts of 4
hosting extremely high star formation rates (SFRs). The quasars are selected to
be individually detected by the \textit{Herschel} SPIRE instrument at 3 at 250 m, leading to typical SFRs of order of 1000
Myr. We find the average SFRs to increase by almost a factor
10 from to , mirroring the rise in the comoving SFR density
over the same epoch. However, we find that the SFRs remain approximately
constant with increasing accretion luminosity for accretion luminosities above
10 L. We also find that the SFRs do not correlate with black
hole mass. Both of these results are most plausibly explained by the existence
of a self-regulation process by the starburst at high SFRs, which controls SFRs
on time-scales comparable to or shorter than the AGN or starburst duty cycles.
We additionally find that SFRs do not depend on Eddington ratio at any
redshift, consistent with no relation between SFR and black hole growth rate
per unit black hole mass. Finally, we find that high-ionisation broad
absorption line (HiBAL) quasars have indistinguishable far-infrared properties
to those of classical quasars, consistent with HiBAL quasars being normal
quasars observed along a particular line of sight, with the outflows in HiBAL
quasars not having any measurable effect on the star formation in their hosts.Comment: 12 pages, 6 figure
Entanglement between a diamond spin qubit and a photonic time-bin qubit at telecom wavelength
We report on the realization and verification of quantum entanglement between
an NV electron spin qubit and a telecom-band photonic qubit. First we generate
entanglement between the spin qubit and a 637 nm photonic time-bin qubit,
followed by photonic quantum frequency conversion that transfers the
entanglement to a 1588 nm photon. We characterize the resulting state by
correlation measurements in different bases and find a lower bound to the Bell
state fidelity of F = 0.77 +/- 0.03. This result presents an important step
towards extending quantum networks via optical fiber infrastructure
The Dirty Dozen Scale: Validation of a Polish Version and Extension of the Nomological Net
In five studies (total N = 1300) we developed and validated a Polish version of the Dirty Dozen measure (DTDD-P) that measures the three traits of the Dark Triad, Machiavellianism, psychopathy, and narcissism. We detail the presence and stability of a bifactor structure of the 12 items and present evidence for good internal consistency and testâretest reliability. We examine the nomological network surrounding the Dark Triad and show that both the Dark Triad total score and the subscales have acceptable validity. We also present evidence on the Dark Triad and moral behavior. Dark Triad predicts utilitarian moral choice (e.g., approval for sacrificing somebody's life for the sake of saving others) and this link is mediated by low empathic concern. In total, our results suggest that the Polish Dirty DozenâParszywa Dwunastkaâis valid, stable, and useful for the study of lingering puzzles in the literature
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