144 research outputs found
A search for low-mass WIMPs with EDELWEISS-II heat-and-ionization detectors
We report on a search for low-energy (E < 20 keV) WIMP-induced nuclear
recoils using data collected in 2009 - 2010 by EDELWEISS from four germanium
detectors equipped with thermal sensors and an electrode design (ID) which
allows to efficiently reject several sources of background. The data indicate
no evidence for an exponential distribution of low-energy nuclear recoils that
could be attributed to WIMP elastic scattering after an exposure of 113 kg.d.
For WIMPs of mass 10 GeV, the observation of one event in the WIMP search
region results in a 90% CL limit of 1.0x10^-5 pb on the spin-independent
WIMP-nucleon scattering cross-section, which constrains the parameter space
associated with the findings reported by the CoGeNT, DAMA and CRESST
experiments.Comment: PRD rapid communication accepte
Axion searches with the EDELWEISS-II experiment
We present new constraints on the couplings of axions and more generic
axion-like particles using data from the EDELWEISS-II experiment. The EDELWEISS
experiment, located at the Underground Laboratory of Modane, primarily aims at
the direct detection of WIMPs using germanium bolometers. It is also sensitive
to the low-energy electron recoils that would be induced by solar or dark
matter axions. Using a total exposure of up to 448 kg.d, we searched for
axion-induced electron recoils down to 2.5 keV within four scenarios involving
different hypotheses on the origin and couplings of axions. We set a 95% CL
limit on the coupling to photons GeV in
a mass range not fully covered by axion helioscopes. We also constrain the
coupling to electrons, , similar to the more
indirect solar neutrino bound. Finally we place a limit on , where is the
effective axion-nucleon coupling for Fe. Combining these results we
fully exclude the mass range keV for DFSZ axions and
keV for KSVZ axions
Background studies for the EDELWEISS dark matter experiment
The EDELWEISS-II collaboration has completed a direct search for WIMP dark
matter using cryogenic Ge detectors (400 g each) and 384 kgdays of
effective exposure. A cross-section of pb is excluded at
90% C.L. for a WIMP mass of 85 GeV. The next phase, EDELWEISS-III, aims to
probe spin-independent WIMP-nucleon cross-sections down to a few
pb. We present here the study of gamma and neutron background
coming from radioactive decays in the set-up and shielding materials. We have
carried out Monte Carlo simulations for the completed EDELWEISS-II setup with
GEANT4 and normalised the expected background rates to the measured
radioactivity levels (or their upper limits) of all materials and components.
The expected gamma-ray event rate in EDELWEISS-II at 20-200 keV agrees with the
observed rate of 82 events/kg/day within the uncertainties in the measured
concentrations. The calculated neutron rate from radioactivity of 1.0-3.1
events (90% C.L.) at 20-200 keV in the EDELWEISS-II data together with the
expected upper limit on the misidentified gamma-ray events (), surface
betas (), and muon-induced neutrons (), do not contradict 5
observed events in nuclear recoil band. We have then extended the simulation
framework to the EDELWEISS-III configuration with 800 g crystals, better
material purity and additional neutron shielding inside the cryostat. The
gamma-ray and neutron backgrounds in 24 kg fiducial mass of EDELWEISS-III have
been calculated as 14-44 events/kg/day and 0.7-1.4 events per year,
respectively. The results of the background studies performed in the present
work have helped to select better purity components and improve shielding in
EDELWEISS-III to further reduce the expected rate of background events in the
next phase of the experiment.Comment: 15 pages, 9 figures, to be published in Astroparticle Physic
Are waiting times for hospital admissions affected by patients' choices and mobility?
Background
Waiting times for elective care have been considered a serious problem in many health care systems. A topic of particular concern has been how administrative boundaries act as barriers to efficient patient flows. In Norway, a policy combining patient's choice of hospital and removal of restriction on referrals was introduced in 2001, thereby creating a nationwide competitive referral system for elective hospital treatment. The article aims to analyse if patient choice and an increased opportunity for geographical mobility has reduced waiting times for individual elective patients.
Methods
A survey conducted among Norwegian somatic patients in 2004 gave information about whether the choice of hospital was made by the individual patient or by others. Survey data was then merged with administrative data on which hospital that actually performed the treatment. The administrative data also gave individual waiting time for hospital admission. Demographics, socio-economic position, and medical need were controlled for to determine the effect of choice and mobility upon waiting time. Several statistical models, including one with instrument variables for choice and mobility, were run.
Results
Patients who had neither chosen hospital individually nor bypassed the local hospital for other reasons faced the longest waiting times. Next were patients who individually had chosen the local hospital, followed by patients who had not made an individual choice, but had bypassed the local hospital for other reasons. Patients who had made a choice to bypass the local hospitals waited on average 11 weeks less than the first group.
Conclusion
The analysis indicates that a policy combining increased opportunity for hospital choice with the removal of rules restricting referrals can reduce waiting times for individual elective patients. Results were robust over different model specifications
The quality of communication about older patients between hospital physicians and general practitioners: a panel study assessment
<p>Abstract</p> <p>Background</p> <p>Optimal care of patients is dependent on good professional interaction between general practitioners and general hospital physicians. In Norway this is mainly based upon referral and discharge letters. The main objectives of this study were to assess the quality of the written communication between physicians and to estimate the number of patients that could have been treated at primary care level instead of at a general hospital.</p> <p>Methods</p> <p>This study comprised referral and discharge letters for 100 patients above 75 years of age admitted to orthopaedic, pulmonary and cardiological departments at the city general hospital in Trondheim, Norway. The assessments were done using a Delphi technique with two expert panels, each with one general hospital specialist, one general practitioner and one public health nurse using a standardised evaluation protocol with a visual analogue scale (VAS). The panels assessed the quality of the description of the patient's actual medical condition, former medical history, signs, medication, Activity of Daily Living (ADL), social network, need of home care and the benefit of general hospital care.</p> <p>Results</p> <p>While information in the referral letters on actual medical situation, medical history, symptoms, signs and medications was assessed to be of high quality in 84%, 39%, 56%, 56% and 39%, respectively, the corresponding information assessed to be of high quality in discharge letters was for actual medical situation 96%, medical history 92%, symptoms 60%, signs 55% and medications 82%. Only half of the discharge letters had satisfactory information on ADL. Some two-thirds of the patients were assessed to have had large health benefits from the general hospital care in question. One of six patients could have been treated without a general hospital admission. The specialists assessed that 77% of the patients had had a large benefit from the general hospital care; however, the general practitioners assessment was only 59%. One of four of the discharge letters did not describe who was responsible for follow-up care.</p> <p>Conclusion</p> <p>In this study from one general hospital both referral and discharge letters were missing vital medical information, and referral letters to such an extent that it might represent a health hazard for older patients. There was also low consensus between health professionals at primary and secondary level of what was high benefit of care for older patients at a general hospital.</p
Impact of periodic health examination on surgical treatment for uterine fibroids in Beijing: a case-control study
<p>Abstract</p> <p>Background</p> <p>During the past 2 decades, there has been a rapid proliferation of "health examination center (HEC)" across China. The effects of their services on public's health have not been systemically investigated. This study aimed to assess the impact of periodic health examination (PHE) at HEC on surgical treatment for uterine fibroids in Beijing residents.</p> <p>Methods</p> <p>We identified 224 patients with a primary diagnosis of uterine fibroids who had surgical treatment at four Level-1 general hospitals in Beijing, from June 1, 2009 to October 20, 2009. Controls were women who did not have surgery for uterine fibroids, matched (1:1 ratio) for age (within 2 years). A standard questionnaire was used to inquire about whether participants had PHE at HEC during the previous 2 years.</p> <p>Results</p> <p>PHE at HEC within 2 years were associated with surgical treatment for uterine fibroids. Odds ratios was 4.05 (95% CI, 2.61-6.29 P < 0.001), after adjustment for marital status, whether have children, annual family income, health insurance, education level and self-rated uterine fibroids-related symptom severity.</p> <p>Conclusions</p> <p>Our study showed PHE currently provided at HEC in China were associated with significantly increased use of surgical treatment for uterine fibroids in women. Further studies are needed to assess the effects of PHE on clinical as well as on broad societal outcomes in Chinese in contemporary medical settings.</p
Estimating EQ-5D utilities based on the Short-Form Long Term Conditions Questionnaire (LTCQ-8)
Purpose: The aim of this work was to develop a mapping algorithm for estimating EuroQoL 5 Dimension (EQ-5D) utilities from responses to the Long-Term Conditions Questionnaire (LTCQ), thus increasing LTCQâs potential as a comprehensive outcome measure for evaluating integrated care initiatives. Methods: We combined data from three studies to give a total sample of 1334 responses. In each of the three datasets, we randomly selected 75% of the sample and combined the selected random samples to generate the estimation dataset, which consisted of 1001 patients. The unselected 25% observations from each dataset were combined to generate an internal validation dataset of 333 patients. We used direct mapping models by regressing responses to the LTCQ-8 directly onto EQ-5D-5L and EQ-5D-3L utilities as well as response (or indirect) mapping to predict the response level that patients selected for each of the five EQ-5D-5L domains. Several models were proposed and compared on mean squared error and mean absolute error. Results: A two-part model with OLS was the best performing based on the mean squared error (0.038) and mean absolute error (0.147) when estimating the EQ-5D-5L utilities. A multinomial response mapping model using LTCQ-8 responses was used to predict EQ-5D-5L responses levels. Conclusions: This study provides a mapping algorithm for estimating EQ-5D utilities from LTCQ responses. The results from this study can help broaden the applicability of the LTCQ by producing utility values for use in economic analyses
SN 2022joj: A Potential Double Detonation with a Thin Helium shell
We present photometric and spectroscopic data for SN 2022joj, a nearby
peculiar Type Ia supernova (SN Ia) with a fast decline rate ( mag). SN 2022joj shows exceedingly red colors, with a value of
approximately mag during its initial stages, beginning from
days before maximum brightness. As it evolves the flux shifts towards the
blue end of the spectrum, approaching mag around maximum
light. Furthermore, at maximum light and beyond, the photometry is consistent
with that of typical SNe Ia. This unusual behavior extends to its spectral
characteristics, which initially displayed a red spectrum and later evolved to
exhibit greater consistency with typical SNe Ia. We consider two potential
explanations for this behavior: double detonation from a helium shell on a
sub-Chandrasekhar-mass white dwarf and Chandrasekhar-mass models with a shallow
distribution of . The shallow nickel models could not reproduce
the red colors in the early light curves. Spectroscopically, we find strong
agreement between SN 2022joj and double-detonation models with white dwarf
masses around 1 and thin He-shell between 0.01 and 0.02
. Moreover, the early red colors are explained by
line-blanketing absorption from iron-peak elements created by the double
detonation scenario in similar mass ranges. However, the nebular spectra
composition in SN 2022joj deviates from expectations for double detonation, as
we observe strong [Fe III] emission instead of [Ca II] lines as anticipated
from double detonation models. More detailed modeling, e.g., including viewing
angle effects, is required to test if double detonation models can explain the
nebular spectra
Keck Infrared Transient Survey I: Survey Description and Data Release 1
We present the Keck Infrared Transient Survey (KITS), a NASA Key Strategic
Mission Support program to obtain near-infrared (NIR) spectra of astrophysical
transients of all types, and its first data release, consisting of 105 NIR
spectra of 50 transients. Such a data set is essential as we enter a new era of
IR astronomy with the James Webb Space Telescope (JWST) and the upcoming Nancy
Grace Roman Space Telescope (Roman). NIR spectral templates will be essential
to search JWST images for stellar explosions of the first stars and to plan an
effective Roma} SN Ia cosmology survey, both key science objectives for mission
success. Between 2022 February and 2023 July, we systematically obtained 274
NIR spectra of 146 astronomical transients, representing a significant increase
in the number of available NIR spectra in the literature. The first data
release includes data from the 2022A semester. We systematically observed three
samples: a flux-limited sample that includes all transients 17 mag in a red
optical band (usually ZTF r or ATLAS o bands); a volume-limited sample
including all transients within redshift ( Mpc); and
an SN Ia sample targeting objects at phases and light-curve parameters that had
scant existing NIR data in the literature. The flux-limited sample is 39%
complete (60% excluding SNe Ia), while the volume-limited sample is 54%
complete and is 79% complete to . All completeness numbers will rise
with the inclusion of data from other telescopes in future data releases.
Transient classes observed include common Type Ia and core-collapse supernovae,
tidal disruption events (TDEs), luminous red novae, and the newly categorized
hydrogen-free/helium-poor interacting Type Icn supernovae. We describe our
observing procedures and data reduction using Pypeit, which requires minimal
human interaction to ensure reproducibility
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