496 research outputs found
I Hear Your Voice In The Shadows
https://digitalcommons.library.umaine.edu/mmb-vp/1659/thumbnail.jp
Cost-effectiveness of the Da Qing Diabetes Prevention program : a modelling study
Objective The Da Qing Diabetes Prevention program (DQDP) was a randomized lifestyle modification intervention conducted in 1986 for the prevention and control of type 2 diabetes in individuals with impaired glucose tolerance. The current study estimated long-term cost-effectiveness of the program based on the health utilities from the Chinese population. Methods A Markov Monte Carlo model was developed to estimate the impact of the intervention from the healthcare system perspective. The analysis was run over 30-year and lifetime periods and costs were estimated respectively as health management service costs. Baseline characteristics and intervention effects were assessed from the DQDP. Utilities and costs were generated from relevant literature. The outcome measures were program cost per quality-adjusted life-years (QALYs) gained and incremental cost-effectiveness ratio (ICER) of the intervention. Sensitivity analyses and threshold analyses were performed. Results Using a 30-year horizon, the intervention strategy was cost-saving and was associated with better health outcomes (increase of 0.74 QALYs per intervention participant). Using a lifetime horizon, the intervention strategy was cost-saving and was associated with additional 1.44 QALYs. Sensitivity analyses showed that the overall ICER was most strongly influenced by the hazard ratio of cardiovascular disease event. Conclusions The Da Qing lifestyle intervention in a Chinese population with impaired glucose tolerance is likely to translate into substantial economic value. It is cost-saving over a 30-year time and lifetime frame
Impact of controlled neonicotinoid exposure on bumblebees in a realistic field setting
1. Pesticide exposure has been implicated as a contributor to insect pollinator declines. In social bees, which are crucial pollination service providers, the effect of low-level chronic exposure is typically non-lethal leading researchers to consider whether exposure induces sub-lethal effects on behaviour and whether such impairment can affect colony development. 2. Studies under laboratory conditions can control levels of pesticide exposure and elucidate causative effects, but are often criticised for being unrealistic. In contrast, field studies can monitor bee responses under a more realistic pesticide exposure landscape; yet typically such findings are limited to correlative results, and can lack true controls or sufficient replication. We attempt to bridge this gap by exposing bumblebees to known amounts of pesticides when colonies are placed in the field. 3. Using 20 bumblebee colonies, we assess the consequences of exposure to the neonicotinoid clothianidin, provided in sucrose at a concentration of five parts per billion, over five weeks. We monitored foraging patterns and pollen collecting performance from 3282 bouts using either a non-invasive photographic assessment, or by extracting the pollen from returning foragers. We also conducted a full colony census at the beginning and end of the experiment. 4. In contrast to studies on other neonicotinoids, showing clear impairment to foraging behaviours, we detected only subtle changes to patterns of foraging activity and pollen foraging during the course of the experiment. However, our colony census measures showed a more pronounced effect of exposure, with fewer adult workers and sexuals in treated colonies after five weeks. 5. Synthesis and applications. Pesticide induced impairments on colony development and foraging could impact on the pollination service that bees provide. Therefore our findings, that bees show subtle changes in foraging behaviour and reductions in colony size after exposure to a common pesticide, has important implications and helps to inform the debate over whether the benefits of systemic pesticide application to flowering crops outweigh the costs. We propose that our methodology is an important advance to previous semi-field methods and should be considered when considering improvements to current ecotoxicological guidelines for pesticide risk assessment
The fine-structure of volatility feedback I: multi-scale self-reflexivity
We attempt to unveil the fine structure of volatility feedback effects in the
context of general quadratic autoregressive (QARCH) models, which assume that
today's volatility can be expressed as a general quadratic form of the past
daily returns. The standard ARCH or GARCH framework is recovered when the
quadratic kernel is diagonal. The calibration of these models on US stock
returns reveals several unexpected features. The off-diagonal (non ARCH)
coefficients of the quadratic kernel are found to be highly significant both
In-Sample and Out-of-Sample, but all these coefficients turn out to be one
order of magnitude smaller than the diagonal elements. This confirms that daily
returns play a special role in the volatility feedback mechanism, as postulated
by ARCH models. The feedback kernel exhibits a surprisingly complex structure,
incompatible with models proposed so far in the literature. Its spectral
properties suggest the existence of volatility-neutral patterns of past
returns. The diagonal part of the quadratic kernel is found to decay as a
power-law of the lag, in line with the long-memory of volatility. Finally,
QARCH models suggest some violations of Time Reversal Symmetry in financial
time series, which are indeed observed empirically, although of much smaller
amplitude than predicted. We speculate that a faithful volatility model should
include both ARCH feedback effects and a stochastic component
Phylogenetic analysis of the mitochondrial cytochrome c oxidase subunit 1 gene from 13 sipunculan genera: intra- and interphylum relationships
Sipunculans are a phylum of non-segmented, marine worms. Although they are well characterized morphologically, relationships within the phylum and the relationship of Sipuncula to other spiralian phyla have been strongly debated. I analyzed representatives of 13 of 17 described genera using a 654-bp fragment of the mitochondrial gene, cytochrome c oxidase subunit I, to construct the first intraphylum phylogenetic hypothesis for sipunculans based on molecular sequence data. Within the phylum, tree topologies are loosely congruent with a previously published morphological analysis, except that the monotypic genus Phascolopsis occurred within the Golfingiaformes as a sister group to, or nested within, the Themistidae. Phylogenetic analyses, including 30 sequences from additional invertebrate taxa, suggest that sipunculans are most closely related to the Annelida (including Echiura). A previously proposed sipunculan-molluscan relationship is not supported. While not universally accepted, this hypothesis is consistent with other recent and past data on phylum-level relationships.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75669/1/j.1744-7410.2003.tb00089.x.pd
Polyphasic taxonomy of Aspergillus section Usti
Aspergillus ustus is a very common species in foods, soil and
indoor environments. Based on chemical, molecular and morphological data,
A. insuetus is separated from A. ustus and revived. A.
insuetus differs from A. ustus in producing drimans and
ophiobolin G and H and not producing ustic acid and austocystins. The
molecular, physiological and morphological data also indicated that another
species, A. keveii sp. nov. is closely related but distinct
from A. insuetus. Aspergillus section Usti sensu
stricto includes 8 species: A. ustus, A. puniceus, A.
granulosus, A. pseudodeflectus, A. calidoustus, A. insuetus and
A. keveii together with Emericella heterothallica
IL-21 production by CD4+ effector T cells and frequency of circulating follicular helper T cells are increased in type 1 diabetes patients.
AIMS/HYPOTHESIS: Type 1 diabetes results from the autoimmune destruction of insulin-secreting pancreatic beta cells by T cells. Despite the established role of T cells in the pathogenesis of the disease, to date, with the exception of the identification of islet-specific T effector (Teff) cells, studies have mostly failed to identify reproducible alterations in the frequency or function of T cell subsets in peripheral blood from patients with type 1 diabetes. METHODS: We assessed the production of the proinflammatory cytokines IL-21, IFN-γ and IL-17 in peripheral blood mononuclear cells from 69 patients with type 1 diabetes and 61 healthy donors. In an additional cohort of 30 patients with type 1 diabetes and 32 healthy donors, we assessed the frequency of circulating T follicular helper (Tfh) cells in whole blood. IL-21 and IL-17 production was also measured in peripheral blood mononuclear cells (PBMCs) from a subset of 46 of the 62 donors immunophenotyped for Tfh. RESULTS: We found a 21.9% (95% CI 5.8, 40.2; p = 3.9 × 10(-3)) higher frequency of IL-21(+) CD45RA(-) memory CD4(+) Teffs in patients with type 1 diabetes (geometric mean 5.92% [95% CI 5.44, 6.44]) compared with healthy donors (geometric mean 4.88% [95% CI 4.33, 5.50]). Consistent with this finding, we found a 14.9% increase in circulating Tfh cells in the patients (95% CI 2.9, 26.9; p = 0.016). CONCLUSIONS/INTERPRETATION: These results indicate that increased IL-21 production is likely to be an aetiological factor in the pathogenesis of type 1 diabetes that could be considered as a potential therapeutic target.This work was supported by the JDRF UK Centre for
Diabetes - Genes, Autoimmunity and Prevention (D-GAP; 4-2007-1003) in collaboration with M. Peakman and T. Tree at King’s College
London, the JDRF, the Wellcome Trust (WT; WT061858/091157 and
083650/Z/07/Z) and the National Institute for Health Research
Cambridge Biomedical Research Centre (CBRC). The Cambridge
Institute for Medical Research (CIMR) is in receipt of a Wellcome Trust
Strategic Award (100140). RCF is funded by a JDRF post-doctoral fellowship
(3-2011-374). CW is funded by the Wellcome Trust (088998).
The funding organisations had no involvement with the design and
conduct of the study; collection,management, analysis, and interpretation
of the data; and preparation, review, or approval of the manuscript.This is the final published version. It first appeared at http://link.springer.com/article/10.1007%2Fs00125-015-3509-8
The Fungal Cell Wall : Structure, Biosynthesis, and Function
N.G. is funded by the Wellcome Trust via a senior investigator award and a strategic award and by the MRC Centre for Medical Mycology. C.M. acknowledges the support of the Wellcome Trust and the MRC. N.G. and C.M. are part of the MRC Centre for Medical Mycology. J.P.L. acknowledges support from ANR, Aviesan, and FRM.Peer reviewedPublisher PD
Lyapunov spectral analysis of a nonequilibrium Ising-like transition
By simulating a nonequilibrium coupled map lattice that undergoes an
Ising-like phase transition, we show that the Lyapunov spectrum and related
dynamical quantities such as the dimension correlation length~ are
insensitive to the onset of long-range ferromagnetic order. As a function of
lattice coupling constant~ and for certain lattice maps, the Lyapunov
dimension density and other dynamical order parameters go through a minimum.
The occurrence of this minimum as a function of~ depends on the number of
nearest neighbors of a lattice point but not on the lattice symmetry, on the
lattice dimensionality or on the position of the Ising-like transition. In
one-space dimension, the spatial correlation length associated with magnitude
fluctuations and the length~ are approximately equal, with both
varying linearly with the radius of the lattice coupling.Comment: 29 pages of text plus 15 figures, uses REVTeX macros. Submitted to
Phys. Rev. E
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