2,150 research outputs found
Precision Spectroscopy of Molecular Hydrogen Ions: Towards Frequency Metrology of Particle Masses
We describe the current status of high-precision ab initio calculations of
the spectra of molecular hydrogen ions (H_2^+ and HD^+) and of two experiments
for vibrational spectroscopy. The perspectives for a comparison between theory
and experiment at a level of 1 ppb are considered.Comment: 26 pages, 13 figures, 1 table, to appear in "Precision Physics of
Simple Atomic Systems", Lecture Notes in Physics, Springer, 200
Effects of dipole position, orientation and noise on the accuracy of EEG source localization
BACKGROUND: The electroencephalogram (EEG) reflects the electrical activity in the brain on the surface of scalp. A major challenge in this field is the localization of sources in the brain responsible for eliciting the EEG signal measured at the scalp. In order to estimate the location of these sources, one must correctly model the sources, i.e., dipoles, as well as the volume conductor in which the resulting currents flow. In this study, we investigate the effects of dipole depth and orientation on source localization with varying sets of simulated random noise in 4 realistic head models. METHODS: Dipole simulations were performed using realistic head models and using the boundary element method (BEM). In all, 92 dipole locations placed in temporal and parietal regions of the head with varying depth and orientation were investigated along with 6 different levels of simulated random noise. Localization errors due to dipole depth, orientation and noise were investigated. RESULTS: The results indicate that there are no significant differences in localization error due tangential and radial dipoles. With high levels of simulated Gaussian noise, localization errors are depth-dependant. For low levels of added noise, errors are similar for both deep and superficial sources. CONCLUSION: It was found that if the signal-to-noise ratio is above a certain threshold, localization errors in realistic head models are, on average the same for deep and superficial sources. As the noise increases, localization errors increase, particularly for deep sources
Brucellosis remains a neglected disease inthe developing world: a call forinterdisciplinary action
Brucellosis places significant burdens on the human healthcare system and limits the economic growth of individuals, communities, and nations where such development is especially important to diminish the prevalence of poverty. The implementation of public policy focused on mitigating the socioeconomic effects of brucellosis in human and animal populations is desperately needed. When developing a plan to mitigate the associated consequences, it is vital to consider both the abstract and quantifiable effects. This requires an interdisciplinary and collaborative, or One Health, approach that consists of public education, the development of an infrastructure for disease surveillance and reporting in both veterinary and medical fields, and campaigns for control in livestock and wildlife species
Guided Electromagnetic Discharge Pulses Driven by Short Intense Laser Pulses: Characterisation and Modelling
Strong electromagnetic pulses (EMP) are generated from intense laser
interactions with solid-density targets, and can be guided by the target
geometry, specifically through conductive connections to the ground. We present
an experimental characterization, by time- and spatial-resolved proton
deflectometry, of guided electromagnetic discharge pulses along wires including
a coil, driven by 0.5 ps, 50 J, 1e19 W/cm2 laser pulses. Proton-deflectometry
data allows to time-resolve first the EMP due to the laser-driven target
charging and then the return EMP from the ground through the conductive target
stalk. Both EMPs have a typical duration of tens of ps and correspond to
currents in the kA-range with electric-field amplitudes of multiple GV/m. The
sub-mm coil in the target rod creates lensing effects on probing protons, due
to both magnetic- and electric-field contributions. This way, protons of 10
MeV-energy range are focused over cm-scale distances. Experimental results are
supported by analytical modelling and high-resolution numerical
particle-in-cell simulations, unraveling the likely presence of a surface
plasma, which parameters define the discharge pulse dispersion in the
non-linear propagation regime
The polarization observables T, P, and H and their impact on multipoles
Data on the polarization observables T, P, and H for the reaction are reported. Compared to earlier data from other experiments, our
data are more precise and extend the covered range in energy and angle
substantially. The results were extracted from azimuthal asymmetries measured
using a transversely polarized target and linearly polarized photons. The data
were taken at the Bonn electron stretcher accelerator ELSA with the CBELSA/TAPS
detector. Within the Bonn-Gatchina partial wave analysis, the new polarization
data lead to a significant narrowing of the error band for the multipoles for
neutral-pion photoproduction
The N(1520) 3/2- helicity amplitudes from an energy-independent multipole analysis based on new polarization data on photoproduction of neutral pions
New data on the polarization observables T, P, and H for the reaction are reported. The results are extracted from azimuthal
asymmetries when a transversely polarized butanol target and a linearly
polarized photon beam are used. The data were taken at the Bonn electron
stretcher accelerator ELSA using the CBELSA/TAPS detector. These and earlier
data are used to perform a truncated energy-independent partial wave analysis
in sliced-energy bins. This energy-independent analysis is compared to the
results from energy-dependent partial wave analyses
Der frühe Beginn der Zwangsstörung
Einleitung: Die vorliegende Untersuchung geht der Fragestellung nach, ob sich eine Zwangsstörung, die bereits
im Kindes- bzw. Jugendalter beginnt, von einer Zwangsstörung, die erst im Erwachsenenalter beginnt, hinsichtlich Schweregrad und Symptomatik unterscheidet. Patienten und Methoden: Eine Stichprobe von 370 Patienten
mit Zwangsstörung (ICD-10 F42), die sich zwischen 1998
und 2002 stationär in der Psychosomatischen Klinik Windach
befanden, wurde in eine Early-Onset-Gruppe (Störungsbeginn ≤15 Jahre) und in eine Late-Onset-Gruppe (Störungsbeginn ≥16 Jahre) aufgeteilt. Die Gruppen wurden über ICD-10-Diagnosen und Y-BOCSWerte verglichen. Ergebnisse: Beim Schweregrad zeigte sich, dass 20,5% der Early-Onset-Gruppe, aber lediglich 8,7% der Late-Onset-Gruppe unter einer «massiven Zwangsstörung» leiden. Bei der Symptomatik zeigte
sich, dass die Early-Onset-Gruppe häufiger die Diagnose
«Zwangsgedanken und -handlungen gemischt» (76,9%)erhält als die Late-Onset-Gruppe (61,8%). Außerdem nennt die Early-Onset-Gruppe sowohl für die Gegenwart als auch für die Vergangenheit mehr Symptome als die Late-Onset-Gruppe (Gegenwart 8,2 vs. 7,0; Vergangenheit 5,5 vs. 3,9 Symptomgruppen). Weiter ergaben sich inhaltliche Unterschiede der Zwangsgedanken und Zwangshandlungen. Schlussfolgerungen: Early-Onset-Patienten scheinen häufiger von einer massiven Form der Zwangsstörung und einer größeren Symptomvielfalt betroffen zu sein als Late-Onset-Patienten. Ob es sich bei der Zwangsstörung mit Beginn im Kindes- und Jugendalter um einen abgrenzbaren Subtypus handelt, konnte jedoch in dieser Untersuchung nicht eindeutig geklärt werden und bedarf weiterer Forschungen.Introduction: This study investigates if obsessive compulsive disorder with early onset differs in severity and
symptomatology from that with late onset. Patients and
Methods: A sample of 370 patients with obsessive compulsive
disorder (OCD; ICD 10 F42) who received in-patient
treatment at the psychosomatic clinic of Windach between 1998 and 2002 were divided into an early-onset group (onset ≤15 years) and a late-onset group (onset ≥16 years). Groups were compared regarding ICD-10 diagnosis and Y-BOCS scores. Results: Considering severity of the disorder 20.5% of the early-onset group but merely 8.7% of the late-onset group suffered from an extreme form of OCD. With respect to symptomatology, the early-onset group was diagnosed with ‘obsessions and compulsions, mixed’ (76.9%) more often than the lateonset group (61.8%). Also, the early-onset group reported a wider variety of symptoms both for the present and for the past than the late-onset group (present 8,2 vs 7.0; past 5.5 vs 3.9 types of symptoms). There were also differences in the content of rumination and types of compulsive rituals. Conclusions: Patients with early-onset
OCD seem to be more frequently affected by an extreme form of OCD and to experience a higher variety of symptoms than patients with late-onset OCD. If early-onset OCD can be considered a distinct subtype could not be answered unequivocally by the results of this study. This question needs additional research
Global, Regional, and National Burden of Stroke and Its Risk Factors, 1990–2019: A Systematic Analysis for the Global Burden of Disease Study 2019
Background
Regularly updated data on stroke and its pathological types, including data on their incidence, prevalence, mortality, disability, risk factors, and epidemiological trends, are important for evidence-based stroke care planning and resource allocation. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) aims to provide a standardised and comprehensive measurement of these metrics at global, regional, and national levels. Methods
We applied GBD 2019 analytical tools to calculate stroke incidence, prevalence, mortality, disability-adjusted life-years (DALYs), and the population attributable fraction (PAF) of DALYs (with corresponding 95% uncertainty intervals [UIs]) associated with 19 risk factors, for 204 countries and territories from 1990 to 2019. These estimates were provided for ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, and all strokes combined, and stratified by sex, age group, and World Bank country income level. Findings
In 2019, there were 12·2 million (95% UI 11·0–13·6) incident cases of stroke, 101 million (93·2–111) prevalent cases of stroke, 143 million (133–153) DALYs due to stroke, and 6·55 million (6·00–7·02) deaths from stroke. Globally, stroke remained the second-leading cause of death (11·6% [10·8–12·2] of total deaths) and the third-leading cause of death and disability combined (5·7% [5·1–6·2] of total DALYs) in 2019. From 1990 to 2019, the absolute number of incident strokes increased by 70·0% (67·0–73·0), prevalent strokes increased by 85·0% (83·0–88·0), deaths from stroke increased by 43·0% (31·0–55·0), and DALYs due to stroke increased by 32·0% (22·0–42·0). During the same period, age-standardised rates of stroke incidence decreased by 17·0% (15·0–18·0), mortality decreased by 36·0% (31·0–42·0), prevalence decreased by 6·0% (5·0–7·0), and DALYs decreased by 36·0% (31·0–42·0). However, among people younger than 70 years, prevalence rates increased by 22·0% (21·0–24·0) and incidence rates increased by 15·0% (12·0–18·0). In 2019, the age-standardised stroke-related mortality rate was 3·6 (3·5–3·8) times higher in the World Bank low-income group than in the World Bank high-income group, and the age-standardised stroke-related DALY rate was 3·7 (3·5–3·9) times higher in the low-income group than the high-income group. Ischaemic stroke constituted 62·4% of all incident strokes in 2019 (7·63 million [6·57–8·96]), while intracerebral haemorrhage constituted 27·9% (3·41 million [2·97–3·91]) and subarachnoid haemorrhage constituted 9·7% (1·18 million [1·01–1·39]). In 2019, the five leading risk factors for stroke were high systolic blood pressure (contributing to 79·6 million [67·7–90·8] DALYs or 55·5% [48·2–62·0] of total stroke DALYs), high body-mass index (34·9 million [22·3–48·6] DALYs or 24·3% [15·7–33·2]), high fasting plasma glucose (28·9 million [19·8–41·5] DALYs or 20·2% [13·8–29·1]), ambient particulate matter pollution (28·7 million [23·4–33·4] DALYs or 20·1% [16·6–23·0]), and smoking (25·3 million [22·6–28·2] DALYs or 17·6% [16·4–19·0]). Interpretation
The annual number of strokes and deaths due to stroke increased substantially from 1990 to 2019, despite substantial reductions in age-standardised rates, particularly among people older than 70 years. The highest age-standardised stroke-related mortality and DALY rates were in the World Bank low-income group. The fastest-growing risk factor for stroke between 1990 and 2019 was high body-mass index. Without urgent implementation of effective primary prevention strategies, the stroke burden will probably continue to grow across the world, particularly in low-income countries
A Review of Time Courses and Predictors of Lipid Changes with Fenofibric Acid-Statin Combination
Fibrates activate peroxisome proliferator activated receptor α and exert beneficial effects on triglycerides, high-density lipoprotein cholesterol, and low density lipoprotein subspecies. Fenofibric acid (FA) has been studied in a large number of patients with mixed dyslipidemia, combined with a low- or moderate-dose statin. The combination of FA with simvastatin, atorvastatin and rosuvastatin resulted in greater improvement of the overall lipid profile compared with the corresponding statin dose. The long-term efficacy of FA combined with low- or moderate- dose statin has been demonstrated in a wide range of patients, including patients with type 2 diabetes mellitus, metabolic syndrome, or elderly subjects. The FA and statin combination seems to be a reasonable option to further reduce cardiovascular risk in high-risk populations, although trials examining cardiovascular disease events are missing
The Spectroscopic Classification and Explosion Properties of SN2009nz Associated with GRB091127 at z=0.490
We present spectroscopic observations of GRB091127 (z=0.490) at the peak of
the putative associated supernova, SN2009nz. Subtracting a late-time spectrum
of the host galaxy, we isolate the contribution of SN2009nz and uncover broad
features typical of nearby GRB-SNe. This establishes unambiguously that
GRB091127 was accompanied by a broad-lined Type Ic SN, and links a cosmological
long burst with a standard energy release (E_gamma,iso ~ 1.1e52 erg) to a
massive star progenitor. The spectrum of SN2009nz closely resembles that of
SN2006aj, with SN2003dh also providing an acceptable match, but has
significantly narrower features than SNe 1998bw and 2010bh, indicative of a
lower expansion velocity. The photospheric velocity inferred from the SiII 6355
absorption feature, v_ph ~ 17,000 km/s, is indeed closer to that of SNe 2006aj
and 2003dh than to the other GRB-SNe. Combining the measured velocity with the
light curve peak brightness and width, we estimate the following explosion
parameters: M_Ni ~ 0.35 M_sun, E_K ~ 2.3e51 erg, and M_ej ~ 1.4 M_sun, similar
to those of SN2006aj. These properties indicate that SN2009nz follows a trend
of lower M_Ni for GRB-SNe with lower E_K and M_ej. Equally important, since
GRB091127 is a typical cosmological burst, the similarity of SN2009nz to
SN2006aj either casts doubt on the claim that XRF060218/SN2006aj was powered by
a neutron star, or indicates that the nature of the central engine is encoded
in the SN properties but not in the prompt emission. Future spectra of GRB-SNe
at z > 0.3, including proper subtraction of the host galaxy contribution, will
shed light on the full dispersion of SN properties for standard long GRBs, on
the relation between SNe associated with sub-energetic and standard GRBs, and
on a potential dispersion in the associated SN types.Comment: Submitted to ApJ; 11 pages; 2 tables; 4 figures; emulateapj styl
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