6,465 research outputs found
Impacts of energy efficiency retrofitting measures on indoor PM concentrations across different income groups in England: a modelling study
As part of an effort to reduce carbon emissions in the UK, policies encouraging the energy-efficient retrofit of domestic properties are being implemented. Typical retrofits, including installation of insulation and double glazing can cause tightening of the building envelope which may affect indoor air quality (IAQ) impacting occupant health. Using the example of PM (an airborne pollutant with known health impacts), this study considers the influence of energy-efficient retrofits on indoor PM concentrations in domestic properties both above and below the low-income threshold (LIT) for a range of tenancies across England. Simulations using EnergyPlus and its integrated Generic Contaminant model are employed to predict indoor PM exposures from both indoor and outdoor sources in building archetypes representative of (i) the existing housing stock and (ii) a retrofitted English housing stock. The exposures of occupants for buildings occupied by groups above and below the LIT are then estimated under current conditions and following retrofits. One-way ANOVA tests were applied to clarify results and investigate differences between the various income and tenure groups. Results indicate that all tenures below the LIT experience greater indoor PM concentrations than those above, suggesting possible social inequalities driven by housing, leading to consequences for health
Enhanced Zeeman splitting in Ga0.25In0.75As quantum point contacts
The strength of the Zeeman splitting induced by an applied magnetic field is
an important factor for the realization of spin-resolved transport in
mesoscopic devices. We measure the Zeeman splitting for a quantum point contact
etched into a Ga0.25In0.75As quantum well, with the field oriented parallel to
the transport direction. We observe an enhancement of the Lande g-factor from
|g*|=3.8 +/- 0.2 for the third subband to |g*|=5.8 +/- 0.6 for the first
subband, six times larger than in GaAs. We report subband spacings in excess of
10 meV, which facilitates quantum transport at higher temperatures.Comment: [Version 2] Revtex4, 11 pages, 3 figures, accepted for publication in
Applied Physics Letter
Determination of the Baryon Density from Large Scale Galaxy Redshift Surveys
We estimate the degree to which the baryon density, , can be
determined from the galaxy power spectrum measured from large scale galaxy
redshift surveys, and in particular, the Sloan Digital Sky Survey. A high
baryon density will cause wiggles to appear in the power spectrum, which should
be observable at the current epoch. We assume linear theory on scales and do not include the effects of redshift distortions, evolution,
or biasing. With an optimum estimate of to ,
the uncertainties in are roughly 0.07 and 0.016 in flat
and open () cosmological models, respectively. This result
suggests that it should be possible to test for consistency with big bang
nucleosynthesis estimates of if we live in an open universe.Comment: 23 Pages, 10 Postscript figure
Probing the Sensitivity of Electron Wave Interference to Disorder-Induced Scattering in Solid-State Devices
The study of electron motion in semiconductor billiards has elucidated our
understanding of quantum interference and quantum chaos. The central assumption
is that ionized donors generate only minor perturbations to the electron
trajectories, which are determined by scattering from billiard walls. We use
magnetoconductance fluctuations as a probe of the quantum interference and show
that these fluctuations change radically when the scattering landscape is
modified by thermally-induced charge displacement between donor sites. Our
results challenge the accepted understanding of quantum interference effects in
nanostructures.Comment: 8 pages, 5 figures, Submitted to Physical Review
Modelling population exposure to high indoor temperatures under changing climates, housing conditions, and urban environments in England
: The exposure of an individual to heat during hot weather depends on several factors including
local outdoor temperatures and possible Urban Heat Island (UHI) effects, the thermal performance of the
building they inhabit, and any actions that they are able to take in order to modify the indoor thermal
conditions. There is an increasing body of research that seeks to understand how housing, UHI, and
occupant profiles may alter the risk of mortality during hot weather. Housing overheating models have
been of particular interest due to the amount of time spent indoors and the need to improve the energy
efficiency of the UK housing stock. A number of housing overheating models have been created in order to
understand how changes to the building stock and climate may alter heat exposure and risks of heatrelated
mortality. We briefly describe the development of a metamodel â a model derived from the
outputs of EnergyPlus dynamic thermal simulation models of building variants â and its application to a
housing stock model representative of the West Midlands, UK. We model the stock under a âcurrentâ
scenario, as described by the 2010-2011 English Housing Survey, and then following a full energy-efficient
building fabric retrofit or the installation of external window shutters. Initial results indicate a wide range of
overheating risks inside dwelling variants in Birmingham, with flats and bungalows most vulnerable to
overheating, and detached dwellings least vulnerable. Modelling of the full retrofit of buildings indicated
that the stock would experience an overall increase in overheating, while external shutters were able to
decrease overheating significantly
Housing as a modifier of air contaminant and temperature exposure in Great Britain: A modelling framework
This paper presents the development of a modelling framework that quantifies the modifying effect of dwelling characteristics on exposure to indoor air pollution and excess temperature. A georeferenced domestic building stock model of Great Britain was created using national housing surveys, historical weather, and local terrain data. Dynamic building performance simulation was applied to estimate indoor air pollution and overheating risk metrics at the individual building level. These metrics were then aggregated at various geographic units and mapped across Britain within a Geographic Information System (GIS) environment to
compare spatial trends. Results indicate that flats and newly built properties are characterised by lower indoor air pollution from outdoor sources, but higher air pollution from indoor sources. Flats, bungalows and newly built, more airtight dwellings are found to be more prone
to overheating. Consequently, urban populations may experience higher levels of pollution from indoor sources and overheating resulting from the higher prevalence of flats in cities
Nurse practitioner coverage is associated with a decrease in length of stay in a pediatric chronic ventilator dependent unit
AIM:
To hypothesize a dedicated critical care nurse practitioner (NP) is associated with a decreased length of stay (LOS) from a pediatric chronic ventilator dependent unit (PCVDU).
METHODS:
We retrospectively reviewed patients requiring care in the PCVDU from May 2001 through May 2011 comparing the 5 years prior to the 5 years post implementation of the critical care NP in 2005. LOS and room charges were obtained.
RESULTS:
The average LOS decreased from a median of 55 d [interquartile range (IQR): 9.8-108.3] to a median of 12 (IQR: 4.0-41.0) with the implementation of a dedicated critical care NP (P < 1.0001). Post implementation of a dedicated NP, a savings of 25738049 in room charges was noted over 5 years.
CONCLUSION:
Our data demonstrates a critical care NP coverage model in a PCVDU is associated with a significantly reduced LOS demonstrating that the NP is an efficient and likely cost-effective addition to a medically comprehensive service
Associations between multimorbidity and neuropathology in dementia: a case for considering functional cognitive disorders, psychiatric illness, and dementia mimics
Cognitive impairment in older people has a variety of underlying causes. In addition to neurodegenerative causes such as Alzheimer's disease, a dementia-like cognitive disorder may appear due to non-degenerative factors. Multimorbidity has been previously associated with clinical dementia risk, though whether this was due to greater risk of dementia-related neuropathology, or other factors that mimic dementia, was unclear. We provide evidence that physical multimorbidity is not associated with greater pathological changes at autopsy. Other factors related to multimorbidity and cognitive impairments may be important targets for investigation, such as functional cognitive disorders, primary psychiatric disorders (depression, anxiety, psychosis) and polypharmacy
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