2,101 research outputs found
Measurement of Scintillation and Ionization Yield and Scintillation Pulse Shape from Nuclear Recoils in Liquid Argon
We have measured the scintillation and ionization yield of recoiling nuclei
in liquid argon as a function of applied electric field by exposing a
dual-phase liquid argon time projection chamber (LAr-TPC) to a low energy
pulsed narrow band neutron beam produced at the Notre Dame Institute for
Structure and Nuclear Astrophysics. Liquid scintillation counters were arranged
to detect and identify neutrons scattered in the TPC and to select the energy
of the recoiling nuclei. We report measurements of the scintillation yields for
nuclear recoils with energies from 10.3 to 57.3 keV and for median applied
electric fields from 0 to 970 V/cm. For the ionization yields, we report
measurements from 16.9 to 57.3 keV and for electric fields from 96.4 to 486
V/cm. We also report the observation of an anticorrelation between
scintillation and ionization from nuclear recoils, which is similar to the
anticorrelation between scintillation and ionization from electron recoils.
Assuming that the energy loss partitions into excitons and ion pairs from
Kr internal conversion electrons is comparable to that from Bi
conversion electrons, we obtained the numbers of excitons () and ion
pairs () and their ratio () produced by nuclear recoils from
16.9 to 57.3 keV. Motivated by arguments suggesting direction sensitivity in
LAr-TPC signals due to columnar recombination, a comparison of the light and
charge yield of recoils parallel and perpendicular to the applied electric
field is presented for the first time.Comment: v2 to reflect published versio
Determinants of pre-vaccination antibody responses to SARS-CoV-2: a population-based longitudinal study (COVIDENCE UK)
BACKGROUND: Prospective population-based studies investigating multiple determinants of pre-vaccination antibody responses to SARS-CoV-2 are lacking. METHODS: We did a prospective population-based study in SARS-CoV-2 vaccine-naive UK adults recruited between May 1 and November 2, 2020, without a positive swab test result for SARS-CoV-2 prior to enrolment. Information on 88 potential sociodemographic, behavioural, nutritional, clinical and pharmacological risk factors was obtained through online questionnaires, and combined IgG/IgA/IgM responses to SARS-CoV-2 spike glycoprotein were determined in dried blood spots obtained between November 6, 2020, and April 18, 2021. We used logistic and linear regression to estimate adjusted odds ratios (aORs) and adjusted geometric mean ratios (aGMRs) for potential determinants of SARS-CoV-2 seropositivity (all participants) and antibody titres (seropositive participants only), respectively. RESULTS: Of 11,130 participants, 1696 (15.2%) were seropositive. Factors independently associated with higher risk of SARS-CoV-2 seropositivity included frontline health/care occupation (aOR 1.86, 95% CI 1.48–2.33), international travel (1.20, 1.07–1.35), number of visits to shops and other indoor public places (≥ 5 vs. 0/week: 1.29, 1.06–1.57, P-trend = 0.01), body mass index (BMI) ≥ 25 vs. < 25 kg/m(2) (1.24, 1.11–1.39), South Asian vs. White ethnicity (1.65, 1.10–2.49) and alcohol consumption ≥15 vs. 0 units/week (1.23, 1.04–1.46). Light physical exercise associated with lower risk (0.80, 0.70–0.93, for ≥ 10 vs. 0–4 h/week). Among seropositive participants, higher titres of anti-Spike antibodies associated with factors including BMI ≥ 30 vs. < 25 kg/m(2) (aGMR 1.10, 1.02–1.19), South Asian vs. White ethnicity (1.22, 1.04–1.44), frontline health/care occupation (1.24, 95% CI 1.11–1.39), international travel (1.11, 1.05–1.16) and number of visits to shops and other indoor public places (≥ 5 vs. 0/week: 1.12, 1.02–1.23, P-trend = 0.01); these associations were not substantially attenuated by adjustment for COVID-19 disease severity. CONCLUSIONS: Higher alcohol consumption and lower light physical exercise represent new modifiable risk factors for SARS-CoV-2 infection. Recognised associations between South Asian ethnic origin and obesity and higher risk of SARS-CoV-2 seropositivity were independent of other sociodemographic, behavioural, nutritional, clinical, and pharmacological factors investigated. Among seropositive participants, higher titres of anti-Spike antibodies in people of South Asian ancestry and in obese people were not explained by greater COVID-19 disease severity in these groups. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12916-022-02286-4
Photoelectrochemical properties of mesoporous NiOx deposited on technical FTO via nanopowder sintering in conventional and plasma atmospheres
Nanoporous nickel oxide (NiO x ) has been deposited with two different procedures of sintering (CS and RDS). Both samples display solid state oxidation at about 3.1 V vs Li+/Li. Upon sensitization of CS/RDS NiO x with erythrosine b (ERY), nickel oxide oxidation occurs at the same potential. Impedance spectroscopy revealed a higher charge transfer resistance for ERY-sensitized RDS NiO x with respect to sensitized CS NiO x . This was due to the chemisorption of a larger amount of ERY on RDS with respect to CS NiO x . Upon illumination the photoinduced charge transfer between ERY layer and NiO x could be observed only with oxidized CS. Photoelectrochemical effects of sensitized RDS NiO x were evidenced upon oxide reduction. With the addition of iodine RDS NiOx electrodes could give the reduction iodine → iodide in addition to the reduction of RDS NiO x . p-type dye sensitized solar cells were assembled with RDS NiO x photocathodes sensitized either by ERY or Fast Green. Resulting overall efficiencies ranged between 0.02 and 0.04 % upon irradiation with solar spectrum simulator (Iin : 0.1 W cm −2 )
Living with severe allergy: an Anaphylaxis Campaign national survey of young people
<p>Abstract</p> <p>Background</p> <p>The transition to adulthood can be particularly challenging for young people with severe allergies, who must learn to balance personal safety with independent living. Information and support for young people and their families are crucial to successfully managing this transition. We sought to: gather insights into the impact of severe allergies on the lives of young people; explore where young people go for information about anaphylaxis and what information they want and need; identify areas where further support is needed.</p> <p>Methods</p> <p>An online questionnaire survey of young people aged 15–25 years with severe allergies in the United Kingdom (UK) was conducted on behalf of the Anaphylaxis Campaign, the main patient support organisation. Participants were recruited mainly from the Anaphylaxis Campaign membership database and also via allergy clinics and social media. The study was funded by the Anaphylaxis Campaign’s In Memoriam Fund.</p> <p>Results</p> <p>A total of 520 young people responded to the survey. The majority had lived with severe allergies since they were young children; 59% reported having attended Accident and Emergency units as a consequence of their allergies. Only 66% of respondents reported always carrying their epinephrine auto-injectors; only 23% had ever used these. Few were currently receiving specialist allergy care; younger respondents were more likely to be under specialist care (34%) than those 18 years and above (23%). Respondents wanted more information about eating out (56%), travelling (54%) and food labelling (43%). Almost a quarter of respondents (23%) reported needing more information on managing their allergies independently without parental help. Managing allergies in the context of social relationships was a concern for 22% of respondents.</p> <p>Conclusions</p> <p>This survey has identified the information and support needs and gaps in service provision for young people with severe allergies. Healthcare professionals and patient support organisations, with the support of the food industry, can help to meet these needs.</p
A large animal model of RDH5-associated retinopathy recapitulates important features of the human phenotype
Pathogenic variants in retinol dehydrogenase 5 (RDH5) attenuate supply of 11-cis-retinal to photoreceptors leading to a range of clinical phenotypes including night blindness due to markedly slowed rod dark adaptation and in some patients, macular atrophy. Current animal models (such as Rdh5-/- mice) fail to recapitulate the functional or degenerative phenotype. Addressing this need for a relevant animal model we present a new domestic cat model with a loss-of-function missense mutation in RDH5 (c.542G > T; p.Gly181Val). As with patients, affected cats have a marked delay in recovery of dark adaptation. Additionally, the cats develop a degeneration of the area centralis (equivalent to the human macula). This recapitulates the development of macular atrophy that is reported in a subset of patients with RDH5 mutations and is shown in this paper in 7 patients with biallelic RDH5 mutations. There is notable variability in the age at onset of the area centralis changes in the cat, with most developing changes as juveniles but some not showing changes over the first few years of age. There is similar variability in development of macular atrophy in patients and while age is a risk factor, it is hypothesized that genetic modifying loci influence disease severity, and we suspect the same is true in the cat model. This novel cat model provides opportunities to improve molecular understanding of macular atrophy and test therapeutic interventions for RDH5-associated retinopathies
An interdisciplinary intervention for older Taiwanese patients after surgery for hip fracture improves health-related quality of life
Abstract Background The effects of intervention programs on health-related quality of life (HRQOL) of patients with hip fracture have not been well studied. We hypothesized that older patients with hip fracture who received our interdisciplinary intervention program would have better HRQOL than those who did not. Methods A randomized experimental design was used. Older patients with hip fracture (N = 162), 60 to 98 years old, from a medical center in northern Taiwan were randomly assigned to an experimental (n = 80) or control (n = 82) group. HRQOL was measured by the SF-36 Taiwan version at 1, 3, 6, and 12 months after discharge. Results The experimental group had significantly better overall outcomes in bodily pain (β = 9.38, p = 0.002), vitality (β = 9.40, p < 0.001), mental health (β = 8.16, p = 0.004), physical function (β = 16.01, p < 0.001), and role physical (β = 22.66, p < 0.001) than the control group at any time point during the first year after discharge. Physical-related health outcomes (physical functioning, role physical, and vitality) had larger treatment effects than emotional/mental- and social functioning-related health outcomes. Conclusions This interdisciplinary intervention program may improve health outcomes of elders with hip fracture. Our results may provide a reference for health care providers in countries using similar programs with Chinese/Taiwanese immigrant populations. Trial registration NCT01052636http://deepblue.lib.umich.edu/bitstream/2027.42/78259/1/1471-2474-11-225.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78259/2/1471-2474-11-225.pdfPeer Reviewe
Precision measurement of the neutrino velocity with the ICARUS detector in the CNGS beam
During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks
for a total of 1.8 10^17 pot in bunched mode, with a 3 ns narrow width proton
beam bunches, separated by 100 ns. This tightly bunched beam structure allows a
very accurate time of flight measurement of neutrinos from CERN to LNGS on an
event-by-event basis. Both the ICARUS-T600 PMT-DAQ and the CERN-LNGS timing
synchronization have been substantially improved for this campaign, taking
ad-vantage of additional independent GPS receivers, both at CERN and LNGS as
well as of the deployment of the "White Rabbit" protocol both at CERN and LNGS.
The ICARUS-T600 detector has collected 25 beam-associated events; the
corresponding time of flight has been accurately evaluated, using all different
time synchronization paths. The measured neutrino time of flight is compatible
with the arrival of all events with speed equivalent to the one of light: the
difference between the expected value based on the speed of light and the
measured value is tof_c - tof_nu = (0.10 \pm 0.67stat. \pm 2.39syst.) ns. This
result is in agreement with the value previously reported by the ICARUS
collaboration, tof_c - tof_nu = (0.3 \pm 4.9stat. \pm 9.0syst.) ns, but with
improved statistical and systematic errors.Comment: 21 pages, 13 figures, 1 tabl
Spiny lobster development: where does successful metamorphosis to the puerulus occur?: a review
This review re-addresses the question: Where does metamorphosis to the puerulus mainly take place among the shallow-water palinurids? A decade ago we reviewed this ecological question in a paper that focused on phyllosomal development of the western rock lobster, Panulirus cygnus. The main region of occurrence of its metamorphosis was found to be in the slope region beyond the shelf break. Because the puerulus of P. cygnus is a non-feeding stage, it was hypothesised that metamorphosis will not occur until the final phyllosoma has reached some critical, and specific, level of stored energy reserves. For late larval development and successful metamorphosis of P. cygnus, the richest food resources seem to be located in the slope waters adjoining the shelf break off Western Australia. This, like most shelf break areas, is a region of higher zooplankton and micronekton biomass than is usually found further offshore, and is dominated (in winter-spring months) by the warm south-flowing Leeuwin Current. In this new review, distribution and abundance data of final phyllosomas and pueruli are examined from, Panulirusargus, Panulirus cygnus, Panulirus japonicus, Panulirus ornatus and Jasus edwardsii, and where possible, related to features of the satellite imagery of the areas in which they occur. We hypothesise that metamorphosis will occur where the final stages have partaken of sufficient, appropriate nutrition to provide them with a reserve of bioenergetic resources, and this can occur where oceanographic fronts effect greater planktonic productivity and concentrations of food organisms. This may be near the shelf-break, or out to large distances offshore, because of large-scale oceanographic events such as the prevailing current system, its off-shoots, mesoscale eddy fronts, counter-currents, etc. However, we contend that, in terms of population recruitment, metamorphosis in most shallow-water palinurid species occurs mainly in the slope waters adjoining the shelf break of the region to which the species is endemic. Although some final phyllosomas may metamorphose much further offshore, it is unlikely that these pueruli will reach the shore, let alone settle and successfully moult to the juvenile stage. All of the data indicate that successful metamorphosis from the final-stage phyllosoma to the puerulus stage in all species occurs offshore but close to the continental shelf
Calibration of photomultiplier arrays
A method is described that allows calibration and assessment of the linearity of response of an array of photomultiplier tubes. The method does not require knowledge of the photomultiplier single photoelectron response model and uses science data directly, thus eliminating the need for dedicated data sets. In this manner all photomultiplier working conditions (e.g. temperature, external fields, etc.) are exactly matched between calibration and science acquisitions. This is of particular importance in low background experiments such as ZEPLIN-III, where methods involving the use of external light sources for calibration are severely constrained
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