2,693 research outputs found
Multidimensional spectroscopy with a single broadband phase-shaped laser pulse
We calculate the frequency-dispersed nonlinear transmission signal of a
phase-shaped visible pulse to fourth order in the field. Two phase profiles, a
phase-step and phase-pulse, are considered. Two dimensional signals obtained by
varying the detected frequency and phase parameters are presented for a three
electronic band model system. We demonstrate how two-photon and stimulated
Raman resonances can be manipulated by the phase profile and sign, and selected
quantum pathways can be suppressed.Comment: 26 pages, 15 figure
Nutrition provider confidence in the Massachusetts Childhood Obesity Research Demonstration (MA-CORD) study
Objective:
The multi-sector, multi-level Massachusetts Childhood Obesity Research Demonstration (MA-CORD) study resulted in improvements in obesity risk factors among children age 2-4âŻyears enrolled in the Special Supplemental Nutrition program for Women, Infants, and Children (WIC). The goal of this study was to examine whether the MA-CORD intervention increased WIC provider confidence in their ability to identify childhood obesity and obesity-related behaviors.
Methods:
As part of the MA-CORD intervention conducted from 2012 to 2015, we implemented WIC practice changes focused on childhood obesity prevention within two Massachusetts communities. We examined changes in provider confidence to assess childhood obesity risk factors and practice frequency among WIC practices located in MA-CORD intervention communities over a 3-year period, compared to non-intervention sites. We measured provider confidence on a continuous scale using questions previously developed to assess provider and parent confidence to make weight-related behavior change (range 0 to 24).
Results:
There were 205 providers at baseline and 165 at follow-up. WIC providers at intervention sites reported greater confidence in their ability to identify childhood obesity and obesity-related behaviors compared to the usual care sites (ÎČâŻ=âŻ1.01, standard errorâŻ=âŻ0.13). These findings persisted after adjusting for provider gender, years in practice, highest education level, and WIC position.
Conclusions:
The MA-CORD intervention was associated with increased WIC provider confidence to assess children's obesity risk. Interventions that increase confidence in assessing obesity-related behaviors may have salutary effects within WIC programs that serve low-income families
Dye-Sensitized Solar Cells Employing a Single Film of Mesoporous TiO2 Beads Achieve Power Conversion Efficiencies Over 10%
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Phase Transitions of Charged Scalars at Finite Temperature and Chemical Potential
We calculate the grand canonical partition function at the one-loop level for
scalar quantum electrodynamics at finite temperature and chemical potential. A
classical background charge density with a charge opposite that of the scalars
ensures the neutrality of the system. For low density systems we find evidence
of a first order phase transition. We find upper and lower bounds on the
transition temperature below which the charged scalars form a condensate. A
first order phase transition may have consequences for helium-core white dwarf
stars in which it has been argued that such a condensate of charged helium-4
nuclei could exist.Comment: 20 pages, 3 figures. Version accepted for publication in JHE
Hepatitis C Virus Genotype 4 in Ugandan Children and Their Mothers
In Kampala, Uganda, in 2001, hepatitis C virus antibodies were found in 27 (4%) of 603 children and in 62 (12%) of 525 of their mothers. However, only â10% of positive results were confirmed by reverse transcriptionâPCR, which suggests frequent false-positive results or viral clearance. All sequenced types were genotype 4
Geomorphic Gradients in Shallow Seagrass Carbon Stocks
Seagrass meadows are important sinks of organic carbon (Corg), in particular the near-surface Corg pool (†15 cm) compared to deeper sediments. Near-surface carbon is highly susceptible to disturbance and loss to the atmosphere, however, inadequate accounting for variability in this pool of carbon limits their uptake into carbon accounting frameworks. We therefore investigated the spatial variability in seagrass near-surface Corg and biomass Corg across different geomorphic (estuary, lagoonal and reef-associated) and community typologies (pioneer and persistent). Near-surface Corg stock in vegetated areas (25.78 Mg Corg haâ1 ± 26.64) was twice that from unvegetated areas (14.27 Mg Corg haâ1 ± 15.86), reinforcing the paradigm that the presence of seagrass enhances carbon stocks. Lagoonal and reef-associated meadows showed similar Corg stocks (p \u3e 0.05), which were substantially higher (p \u3c 0.05) than estuary meadows. Likewise, persistent seagrass communities (Cymodocea dominance) stored higher (p \u3c 0.05) stocks of Corg than pioneer communities (Halophila and Halodule dominance). Linear regression models showed significant but weak relationships between seagrass cover, shoot density and standing biomass with near-surface Corg stocks, whereas significant and strong relationships were observed for organic matter, dry bulk density and median grain size. The results highlight the need for higher resolution carbon assessments to better understand local and regional variability, in order to better inform carbon accounting and conservation policy
Uptake and transport of novel amphiphilic polyelectrolyte-insulin nanocomplexes by caco-2 cells - towards oral insulin
âThe original publication is available at www.springerlink.comâ. Copyright SpringerPurpose: The influence of polymer architecture on cellular uptake and transport across Caco-2 cells of novel amphiphilic polyelectrolyte-insulin nanocomplexes was investigated. Method: Polyallylamine (PAA) (15 kDa) was grafted with palmitoyl chains (Pa) and subsequently modified with quaternary ammonium moieties (QPa). These two amphiphilic polyelectrolytes (APs) were tagged with rhodamine and their uptake by Caco-2 cells or their polyelectrolyte complexes (PECs) with fluorescein isothiocyanate-insulin (FITC-insulin) uptake were investigated using fluorescence microscopy. The integrity of the monolayer was determined by measurement of transepithelial electrical resistance (TEER). Insulin transport through Caco-2 monolayers was determined during TEER experiments. Result: Pa and insulin were co-localised in the cell membranes while QPa complexes were found within the cytoplasm. QPa complex uptake was not affected by calcium, cytochalasin D or nocodazole. Uptake was reduced by co-incubation with sodium azide, an active transport inhibitor. Both polymers opened tight junctions reversibly where the TEER values fell by up to 35 % within 30 minutes incubation with Caco-2 cells. Insulin transport through monolayers increased when QPa was used (0.27 ngmL-1 of insulin in basal compartment) compared to Pa (0.14 ngmL-1 of insulin in basal compartment) after 2 hours. Conclusion: These APs have been shown to be taken up by Caco-2 cells and reversibly open tight cell junctions. Further work is required to optimise these formulations with a view to maximising their potential to facilitate oral delivery of insulin.Peer reviewe
The search for low-mass axion dark matter with ABRACADABRA-10cm
Two of the most pressing questions in physics are the microscopic nature of
the dark matter that comprises 84% of the mass in the universe and the absence
of a neutron electric dipole moment. These questions would be resolved by the
existence of a hypothetical particle known as the quantum chromodynamics (QCD)
axion. In this work, we probe the hypothesis that axions constitute dark
matter, using the ABRACADABRA-10cm experiment in a broadband configuration,
with world-leading sensitivity. We find no significant evidence for axions, and
we present 95% upper limits on the axion-photon coupling down to the
world-leading level GeV,
representing one of the most sensitive searches for axions in the 0.41 - 8.27
neV mass range. Our work paves a direct path for future experiments capable of
confirming or excluding the hypothesis that dark matter is a QCD axion in the
mass range motivated by String Theory and Grand Unified Theories.Comment: 17 pages, 12 figure
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