62 research outputs found
Development and validation of the delirium risk assessment score (DRAS)
PURPOSE: Development and validation of a delirium risk assessment score. Predisposing risk factors for delirium were used, which are easily assessed at hospital admission without additional clinical or laboratory testing. METHODS: A systematic literature search identified ten risk factors: acute admission, alcohol use > 4 units/day, cognitive impairment, ADL impairment, age > 75 years, earlier delirium, hearing/vision problems, number of medication ≥ 5, number of morbidities > 2 and male. The DRAS was developed in a mixed patient population (N = 842) by the use of univariate and multivariate analyses and -2 log-likelihood calculation to weigh the risk factors. Based on the sensitivity and specificity, a cutoff score was calculated. The validation was performed in 3 cohorts (N = 408, N = 186, N = 365). In cohort 3, the DRAS was compared (AUC, sensitivity and specificity) to 3 instruments (Inouye, Kalisvaart, VMS rules). RESULTS: The delirium incidence was 31.8%, 20.3%, 15.6% and 15.1%. All risk factors were independently predictive for delirium, except male. The multivariate analyses excluded morbidities. The final DRAS consists of 8 items; acute admission, cognitive impairment, alcohol use (3 points), ADLimpairment/mobilityproblems (2 points), higher age, earlier delirium, hearing/vision problems, and medication (1 point). The total score is 15 points and at a cut-of score of 5 or higher the patient is at risk of developing a delirium. The cutoff was at 5 or more points, AUC: 0.76 (95% CI 0.72-0.79), sensitivity 0.77, specificity 0.60. Validation cohorts AUC was 0.75 (95% CI 0.96-0.81), 0.76 (95% CI 0.70-0.83) and 0.78 (95% CI 0.70-0.87), sensitivity 0.71, 0.67 and 0.89 and specificity 0.70, 0.72 and 0.60. The comparison revealed the highest AUC for the DRAS. CONCLUSION: Based on an admission interview, the delirium risk can be easily evaluated using the DRAS shortlist score of predisposing risk factors for delirium in older inpatients
The host-galaxy response to the afterglow of GRB 100901A
For Gamma-Ray Burst 100901A, we have obtained Gemini-North and Very Large
Telescope optical afterglow spectra at four epochs: one hour, one day, three
days and one week after the burst, thanks to the afterglow remaining unusually
bright at late times. Apart from a wealth of metal resonance lines, we also
detect lines arising from fine-structure levels of the ground state of Fe II,
and from metastable levels of Fe II and Ni II at the host redshift (z =
1.4084). These lines are found to vary significantly in time. The combination
of the data and modelling results shows that we detect the fall of the Ni II 4
F9/2 metastable level population, which to date has not been observed. Assuming
that the population of the excited states is due to the UV-radiation of the
afterglow, we estimate an absorber distance of a few hundred pc. This appears
to be a typical value when compared to similar studies. We detect two
intervening absorbers (z = 1.3147, 1.3179). Despite the wide temporal range of
the data, we do not see significant variation in the absorption lines of these
two intervening systems.Comment: 17 pages, 9 figures. Accepted by Monthly Notices of the Royal
Astronomical Society on Jan 11th 201
Infrared and Optical Observations of GRB 030115 and its Extremely Red Host Galaxy: Implications for Dark Bursts
We present near-infrared (nIR) and optical observations of the afterglow of
GRB 030115. Discovered in an infrared search at Kitt Peak 5 hours after the
burst trigger, this afterglow is amongst the faintest observed in the R-band at
an early epoch, and exhibits very red colors, with . The
magnitude of the optical afterglow of GRB 030115 is fainter than many upper
limits for other bursts, suggesting that without early nIR observations it
would have been classified as a ``dark'' burst. Both the color and optical
magnitude of the afterglow are likely due to dust extinction and indicate that
at least some optical afterglows are very faint due to dust along the line of
sight. Multicolor {\it Hubble Space Telescope} observations were also taken of
the host galaxy and the surrounding field. Photometric redshifts imply that the
host, and a substantial number of faint galaxies in the field are at . The overdensity of galaxies is sufficiently great that GRB 030115 may
have occurred in a rich high-redshift cluster. The host galaxy shows extremely
red colors (R-K=5) and is the first GRB host to be classified as an Extremely
Red Object (ERO). Some of the galaxies surrounding the host also show very red
colors, while the majority of the cluster are much bluer, indicating ongoing
unobscured star formation. As it is thought that much of high redshift star
formation occurs in highly obscured environments it may be that GRB 030115
represent a transition object, between the relatively unobscured afterglows
seen to date and a population which are very heavily extinguished, even in the
nIR.Comment: 19 Pages. ApJ 2006, 647, 47
Three intervening galaxy absorbers towards GRB060418: faint and dusty?
We present an analysis of three strong, intervening Mg II absorption systems
(z_abs = 0.603, 0.656, 1.107) towards the optical afterglow of gamma-ray burst
(GRB) 060418. From high resolution UVES spectra we measure metal column
densities and find that the highest redshift absorber exhibits a large amount
of dust depletion compared with DLAs seen in QSO spectra. The intervening z_abs
= 1.107 absorber is also unusual in exhibiting a clear 2175 A bump, the first
time this feature has been definitively detected in a GRB spectrum. The GRB
afterglow spectrum is best fit with a two component extinction curve: an SMC
extinction law at z=1.49 (the redshift of the host) with E(B-V) = 0.07+-0.01
and a Galactic extinction curve at z ~ 1.1 with E(B-V) = 0.08+-0.01. We also
present a moderately deep NTT R-band image of the GRB060418 field and
spectroscopy of four galaxies within 1 arcminute. None of these objects has a
redshift that matches any of the intervening absorbers, and we conclude that
the galaxies responsible for the two intervening Mg II absorbers at z ~ 0.6
have luminosities ~<0.3 L^star.Comment: Accepted for publication in MNRAS (Letters), 5 pages. Updated with
more accurate host positio
A very energetic supernova associated with the gamma-ray burst of 29 March 2003
Over the past five years evidence has mounted that long-duration (> 2 s)
gamma-ray bursts (GRBs)--the most brilliant of all astronomical
explosions--signal the collapse of massive stars in our Universe. This evidence
was originally based on the probable association of one unusual GRB with a
supernova, but now includes the association of GRBs with regions of massive
star formation in distant galaxies, the appearance of supernova-like 'bumps' in
the optical afterglow light curves of several bursts and lines of freshly
synthesized elements in the spectra of a few X-ray afterglows. These
observations support, but do not yet conclusively demonstrate, the idea that
long-duration GRBs are associated with the deaths of massive stars, presumably
arising from core collapse. Here we report evidence that a very energetic
supernova (a hypernova) was temporally and spatially coincident with a GRB at
redshift z = 0.1685. The timing of the supernova indicates that it exploded
within a few days of the GRB, strongly suggesting that core-collapse events can
give rise to GRBs, thereby favouring the 'collapsar' model.Comment: 19 pages, 3 figure
Frailty is associated with in-hospital mortality in older hospitalised COVID-19 patients in the Netherlands:the COVID-OLD study
BACKGROUND: During the first wave of the coronavirus disease 2019 (COVID-19) pandemic, older patients had an increased risk of hospitalisation and death. Reports on the association of frailty with poor outcome have been conflicting. OBJECTIVE: The aim of the present study was to investigate the independent association between frailty and in-hospital mortality in older hospitalised COVID-19 patients in the Netherlands. METHODS: This was a multicentre retrospective cohort study in 15 hospitals in the Netherlands, including all patients aged ≥70 years, who were hospitalised with clinically confirmed COVID-19 between February and May 2020. Data were collected on demographics, co-morbidity, disease severity and Clinical Frailty Scale (CFS). Primary outcome was in-hospital mortality. RESULTS: A total of 1,376 patients were included (median age 78 years (interquartile range 74-84), 60% male). In total, 499 (38%) patients died during hospital admission. Parameters indicating presence of frailty (CFS 6-9) were associated with more co-morbidities, shorter symptom duration upon presentation (median 4 versus 7 days), lower oxygen demand and lower levels of C-reactive protein. In multivariable analyses, the CFS was independently associated with in-hospital mortality: compared with patients with CFS 1-3, patients with CFS 4-5 had a two times higher risk (odds ratio (OR) 2.0 (95% confidence interval (CI) 1.3-3.0)) and patients with CFS 6-9 had a three times higher risk of in-hospital mortality (OR 2.8 (95% CI 1.8-4.3)). CONCLUSIONS: The in-hospital mortality of older hospitalised COVID-19 patients in the Netherlands was 38%. Frailty was independently associated with higher in-hospital mortality, even though COVID-19 patients with frailty presented earlier to the hospital with less severe symptoms
Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector
A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
Measurement of the top-quark mass in tt¯ events with dilepton final states in pp collisions at √s = 7 TeV
Open Access: This article is distributed under the terms of the Creative Commons Attribution License.-- Chatrchyan, S. et al.The top-quark mass is measured in proton-proton collisions at s√=7 TeV using a data sample corresponding to an integrated luminosity of 5.0 fb−1 collected by the CMS experiment at the LHC. The measurement is performed in the dilepton decay channel tt¯→(ℓ+νℓb)(ℓ−ν¯¯ℓb¯), where ℓ=e,μ. Candidate top-quark decays are selected by requiring two leptons, at least two jets, and imbalance in transverse momentum. The mass is reconstructed with an analytical matrix weighting technique using distributions derived from simulated samples. Using a maximum-likelihood fit, the top-quark mass is determined to be 172.5±0.4 (stat.)±1.5 (syst.) GeV.Acknowledge support from BMWF and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); MoER, SF0690030s09 and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France);BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); MSI (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MON, RosAtom, RAS and RFBR (Russia); MSTD (Serbia); SEIDI and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); ThEP, IPST and NECTEC (Thailand); TUBITAK and TAEK (Turkey); NASU (Ukraine); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie program and the European Research Council (European Union); the Leventis Foundation; the A. P. Sloan Foundation; the Alexander von Humboldt Foundation; the Austrian Science Fund (FWF); the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l’Industrie et dans l’Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWTBelgium); the Ministry of Education, Youth and Sports (MEYS) of Czech Republic; the Council of Science and Industrial Research, India; the Compagnia di San Paolo (Torino); and the HOMING PLUS program of Foundation for Polish Science, cofinanced from European Union, Regional Development Fund.Peer Reviewe
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