729 research outputs found
SREBP1c-CRY1 signalling represses hepatic glucose production by promoting FOXO1 degradation during refeeding
published_or_final_versio
A probabilistic threshold model: Analyzing semantic categorization data with the Rasch model
According to the Threshold Theory (Hampton, 1995, 2007) semantic categorization decisions come about through the placement of a threshold criterion along a dimension that represents items' similarity to the category representation. The adequacy of this theory is assessed by applying a formalization of the theory, known as the Rasch model (Rasch, 1960; Thissen & Steinberg, 1986), to categorization data for eight natural language categories and subjecting it to a formal test. In validating the model special care is given to its ability to account for inter- and intra-individual differences in categorization and their relationship with item typicality. Extensions of the Rasch model that can be used to uncover the nature of category representations and the sources of categorization differences are discussed
IAT-TiMeS: Intra-Arterial Thrombectomy Transfer Metric Study in Texas
Objective: We aim to report intra-arterial thrombectomy transfer metrics for ischemic stroke patients that were transferred to hub hospitals for possible intra-arterial thrombectomy in multiple geographic regions throughout the state of Texas and to identify potential barriers and delays in the intra-arterial thrombectomy transfer process.
Method: We prospectively collected data from 8 participating Texas comprehensive stroke/thrombectomy capable centers from 7 major regions in the State of Texas. We collected baseline clinical and imaging data related to the pre-transfer evaluation, transfer metrics, and post-transfer clinical and imaging data.
Results: A total of 103 acute ischemic stroke patients suspected/confirmed to have large vessel occlusions between December 2016 to May 2019 that were transferred to hubs as possible intra-arterial thrombectomy candidates were enrolled. A total of 56 (54%) patients were sent from the spoke to the hub via ground ambulance with 47 (46%) patients traveling via air ambulance. The median spoke arrival to hub arrival time was 174 min, median spoke arrival to departure from spoke was 131 min, and median travel time was 39 min. The spoke arrival time to transfer initiation was 68 min. CT-perfusion obtained at the spoke and earlier initiation of transfer were statistically associated with shorter transfer times.
Conclusion: Transfer of intra-arterial thrombectomy patients in Texas may take over 4 h from spoke arrival to hub arrival. This time may be shortened by earlier transfer initiation and acceptance
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Predictors of Serum Chlorinated Pesticide Concentrations among Prepubertal Russian Boys
Background: Few studies have evaluated predictors of childhood exposure to organochlorine pesticides (OCPs), a class of lipophilic persistent chemicals. Objectives: Our goal was to identify predictors of serum OCP concentrations—hexachlorobenzene (HCB), β-hexachlorocyclohexane (β-HCH), and p,p-dichlorodiphenyldichloroethylene (p,p´-DDE)—among boys in Chapaevsk, Russia. Methods: Between 2003 and 2005, 499 boys 8–9 years of age were recruited in a prospective cohort. The initial study visit included a physical examination; blood collection; health, lifestyle, and food-frequency questionnaires; and determination of residential distance from a local factory complex that produced HCB and β-HCH. Fasting serum samples were analyzed for OCPs at the U.S. Centers for Disease Control and Prevention. General linear regression models were used to identify predictors of the boys’ serum HCB, β-HCH, and p,p´-DDE concentrations. Results: Among 355 boys with OCP measurements, median serum HCB, β-HCH, and p,p´-DDE concentrations were 158, 167, and 284 ng/g lipid, respectively. Lower body mass index, longer breastfeeding duration, and local dairy consumption were associated with higher concentrations of OCPs. Boys who lived 3 years in Chapaevsk predicted higher β-HCH concentrations, and having parents who lacked a high school education predicted higher p,p´-DDE concentrations. Conclusions: Among this cohort of prepubertal Russian boys, predictors of serum OCPs included consumption of local dairy products, longer local residence, and residential proximity to the local factory complex. Citation: Lam T, Williams PL, Burns JS, Sergeyev O, Korrick SA, Lee MM, Birnbaum LS, Revich B, Altshul LM, Patterson DG Jr, Turner WE, Hauser R. 2013. Predictors of serum chlorinated pesticide concentrations among prepubertal Russian boys. Environ Health Perspect 121:1372–1377; http://dx.doi.org/10.1289/ehp.130648
Quantum phase transitions of light
Recently, condensed matter and atomic experiments have reached a length-scale
and temperature regime where new quantum collective phenomena emerge. Finding
such physics in systems of photons, however, is problematic, as photons
typically do not interact with each other and can be created or destroyed at
will. Here, we introduce a physical system of photons that exhibits strongly
correlated dynamics on a meso-scale. By adding photons to a two-dimensional
array of coupled optical cavities each containing a single two-level atom in
the photon-blockade regime, we form dressed states, or polaritons, that are
both long-lived and strongly interacting. Our zero temperature results predict
that this photonic system will undergo a characteristic Mott insulator
(excitations localised on each site) to superfluid (excitations delocalised
across the lattice) quantum phase transition. Each cavity's impressive photon
out-coupling potential may lead to actual devices based on these quantum
many-body effects, as well as observable, tunable quantum simulators. We
explicitly show that such phenomena may be observable in micro-machined diamond
containing nitrogen-vacancy colour centres and superconducting microwave
strip-line resonators.Comment: 11 pages, 5 figures (2 in colour
Monitoring and evaluation of disaster response efforts undertaken by local health departments: a rapid realist review
Investigating High-Energy Proton-Induced Reactions on Spherical Nuclei: Implications for the Pre-Equilibrium Exciton Model
A number of accelerator-based isotope production facilities utilize 100- to
200-MeV proton beams due to the high production rates enabled by high-intensity
beam capabilities and the greater diversity of isotope production brought on by
the long range of high-energy protons. However, nuclear reaction modeling at
these energies can be challenging because of the interplay between different
reaction modes and a lack of existing guiding cross section data. A Tri-lab
collaboration has been formed among the Lawrence Berkeley, Los Alamos, and
Brookhaven National Laboratories to address these complexities by
characterizing charged-particle nuclear reactions relevant to the production of
established and novel radioisotopes. In the inaugural collaboration
experiments, stacked-targets of niobium foils were irradiated at the Brookhaven
Linac Isotope Producer (E=200 MeV) and the Los Alamos Isotope Production
Facility (E=100 MeV) to measure Nb(p,x) cross sections between 50
and 200 MeV. The measured cross-section results were compared with literature
data as well as the default calculations of the nuclear model codes TALYS, CoH,
EMPIRE, and ALICE. We developed a standardized procedure that determines the
reaction model parameters that best reproduce the most prominent reaction
channels in a physically justifiable manner. The primary focus of the procedure
was to determine the best parametrization for the pre-equilibrium two-component
exciton model. This modeling study revealed a trend toward a relative decrease
for internal transition rates at intermediate proton energies (E=20-60 MeV)
in the current exciton model as compared to the default values. The results of
this work are instrumental for the planning, execution, and analysis essential
to isotope production.Comment: 37 pages, 62 figures. Revised version, published in Physical Review
Photonic quantum technologies
The first quantum technology, which harnesses uniquely quantum mechanical
effects for its core operation, has arrived in the form of commercially
available quantum key distribution systems that achieve enhanced security by
encoding information in photons such that information gained by an eavesdropper
can be detected. Anticipated future quantum technologies include large-scale
secure networks, enhanced measurement and lithography, and quantum information
processors, promising exponentially greater computation power for particular
tasks. Photonics is destined for a central role in such technologies owing to
the need for high-speed transmission and the outstanding low-noise properties
of photons. These technologies may use single photons or quantum states of
bright laser beams, or both, and will undoubtably apply and drive
state-of-the-art developments in photonics
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