416 research outputs found
Regression calibration for Cox regression under heteroscedastic measurement error - Determining risk factors of cardiovascular diseases from error-prone nutritional replication data
For instance nutritional data are often subject to severe measurement error, and an adequate adjustment of the estimators is indispensable to avoid deceptive conclusions. This paper discusses and extends the method of regression calibration to correct for measurement error in Cox regression. Special attention is paid to the modelling of quadratic predictors, the role of heteroscedastic measurement error, and the efficient use of replicated measurements of the surrogates. The method is used to analyze data from the German part of the MONICA cohort study on cardiovascular diseases. The results corroborate the importance of taking into account measurement error carefully
Functional Changes in Brain Activity Using Hypnosis: A Systematic Review.
Hypnosis has proven a powerful method in indications such as pain control and anxiety reduction. As recently discussed, it has been yielding increased attention from medical/dental perspectives. This systematic review (PROSPERO-registration-ID-CRD42021259187) aimed to critically evaluate and discuss functional changes in brain activity using hypnosis by means of different imaging techniques. Randomized controlled trials, cohort, comparative, cross-sectional, evaluation and validation studies from three databases-Cochrane, Embase and Medline via PubMed from January 1979 to August 2021-were reviewed using an ad hoc prepared search string and following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. A total of 10,404 articles were identified, 1194 duplicates were removed and 9190 papers were discarded after consulting article titles/abstracts. Ultimately, 20 papers were assessed for eligibility, and 20 papers were included after a hand search (ntotal = 40). Despite a broad heterogenicity of included studies, evidence of functional changes in brain activity using hypnosis was identified. Electromyography (EMG) startle amplitudes result in greater activity in the frontal brain area; amplitudes using Somatosensory Event-Related Potentials (SERPs) showed similar results. Electroencephalography (EEG) oscillations of Ξ activity are positively associated with response to hypnosis. EEG results showed greater amplitudes for highly hypnotizable subjects over the left hemisphere. Less activity during hypnosis was observed in the insula and anterior cingulate cortex (ACC)
Guide for Controlling Cotton Insects in the High Plains, Rolling Plains and Trans-Pecos Areas of Texas.
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Study of the Hot-Spot Temperature During Quench in the Nonplanar Coils of W7-X
The quench protection system of the nonplanar coils of the Wendelstein 7-X stellarator was laid out over 15 years ago. At that time, the assessment of the hot-spot temperature by a basic adiabatic model was done using design values for material and operation parameters. After the operating experience in 2016, the hot-spot temperature is reassessed with the thermal-hydraulic program THEA, using the actual values for delay and dump time. The electrical resistivity of the conduit alloy ismeasured over the whole range of temperatures and in magnetic fields on relevant samples of a conductor, exposed to the hardening heat treatment after winding. The results were fed into THEA. Parametric variations are studied in the calculations, e.g., testing the effect of the quench initiation zone, delay time, and dump resistor. The results suggest that the hot-spot temperature of the conduit in the case of quench is safely within the allowable values even when the dump voltage is reduced compared to the initial design value
Hey ho, whereâd the proton go?; Final deprotonation of O6 within the S3 state of Photosystem II
The deprotonation of O6 within the S3 state marks the final deprotonation event before the formation of oxygenâoxygen bond interactions and eventual production and release of dioxygen. Gaining a thorough understanding of this event, from the proton acceptors involved, to the exfiltration pathways available, is key in determining the nature of the resulting oxygen species, influencing the mechanism through which the first oxygenâoxygen bond forms. Computational analysis, using BS-DFT methodologies, showed that proton abstraction by the local Glu189 residue provides consistent evidence against this being a viable mechanistic pathway due to the lack of a stable product structure. In contrast, abstraction via W3 shows an increasingly stable oxo-oxo product state between r[O5O6]âŻ=âŻ2.1âŻĂ
& 1.9âŻĂ
. The resulting oxo-oxo state is stabilised through donation of
electron character from O6 to Mn1 and
electron character from O6 to O5. This donation from the O6 lone pair is shown to be a key factor in stabilising the oxo-oxo state, in addition to showing the initiation of first O5-O6 bond
Suicidal Ideation Among Children and Young Adults in a 24/7 Messenger-Based Psychological Chat Counseling Service
Suicidality in children and young adults is a pervasive problem: approximately 40% of respondents in epidemiological surveys in German schools reported suicidal ideation, while up to 9% reported a suicide attempt in the past. While there is compelling evidence for the effectiveness of telephone-based hotline services, an increasing preference of adolescents for messenger-based counseling services can be observed. Therefore, the present study aims to investigate the utilization behavior and user satisfaction of users contacting a German messenger-based chat counseling service (âkrisenchatâ) regarding suicidal ideation.
Methods
The present cross-sectional study analyzed retrospective anonymous data on sociodemographic variables, utilization behavior, and user satisfaction of krisenchat users who used the service between May 2020 and July 2021. Chi-square-tests were used to identify associations of sociodemographic characteristics and utilization behavior with suicidal ideation. Mann-Whitney-U-tests were used to compare the user satisfaction and the recommendation-to-others-rate between suicidal and non-suicidal krisenchat-users.
Results
In total, chat data of N = 11,031 users were collected. Of the n = 6,962 users included in the final analysis, n = 1,444 (20.7%) contacted krisenchat because of suicidal ideation. The average user experiencing suicidal ideation was 17 years old, female and currently not receiving other treatment. Further, suicidal ideation was significantly and positively associated with age and non-suicidal self-injury. Regarding utilization patterns, there were significant positive associations between suicidal ideation and counseling session count, mean amount of messages sent, and mean amount of words used per message by the user. User satisfaction was high, with 64.7% (n = 413) of users that answered the feedback survey and experiencing suicidal ideation rating the help they received as at least âgoodâ and a recommendation rate of 89.6% (n = 571). Most importantly, no differences were found between users reporting suicidal ideation and those that do not regarding satisfaction and the probability of recommending the service.
Conclusion
Results imply satisfaction with the counseling service among users with suicidal ideation. Nevertheless, there is a need for further research into messenger-based counseling services regarding the prevention of suicidal behavior in children, youths, and young adults. Longitudinal studies are especially needed to assess the effectiveness of messenger-based interventions.Peer Reviewe
New ultrahigh-resolution picture of Earth's gravity field
We provide an unprecedented ultrahigh resolution picture of Earthâs gravity over all continents and numerous islands within ±60° latitude. This is achieved through augmentation of new satellite and terrestrial gravity with topography data and use of massive parallel computation techniques, delivering local detail at ~200 m spatial resolution. As such, our work is the first-of-its-kind to model gravity at unprecedented fine scales yet with near-global coverage. The new picture of Earthâs gravity encompasses a suite of gridded estimates of gravity accelerations, radial and horizontal field components, and quasi-geoid heights at over 3 billion points covering 80% of Earthâs land masses. We identify new candidate locations of extreme gravity signals, suggesting that the Committee on Data for Science and Technology standard for peak-to-peak variations in free-fall gravity is too low by about 40%. The new models are beneficial for a wide range of scientific and engineering applications and freely available to the public
Modelling chemistry in the nocturnal boundary layer above tropical rainforest and a generalised effective nocturnal ozone deposition velocity for sub-ppbv NOx conditions
Measurements of atmospheric composition have been made over a remote rainforest landscape. A box model has previously been demonstrated to model the observed daytime chemistry well. However the box model is unable to explain the nocturnal measurements of relatively high [NO] and [O3], but relatively low observed [NO2]. It is shown that a one-dimensional (1-D) column model with simple O3 -NOx chemistry and a simple representation of vertical transport is able to explain the observed nocturnal concentrations and predict the likely vertical profiles of these species in the nocturnal boundary layer (NBL). Concentrations of tracers carried over from the end of the night can affect the atmospheric chemistry of the following day. To ascertain the anomaly introduced by using the box model to represent the NBL, vertically-averaged NBL concentrations at the end of the night are compared between the 1-D model and the box model. It is found that, under low to medium [NOx] conditions (NOx <1 ppbv), a simple parametrisation can be used to modify the box model deposition velocity of ozone, in order to achieve good agreement between the box and 1-D models for these end-of-night concentrations of NOx and O3. This parametrisation would could also be used in global climate-chemistry models with limited vertical resolution near the surface. Box-model results for the following day differ significantly if this effective nocturnal deposition velocity for ozone is implemented; for instance, there is a 9% increase in the following dayâs peak ozone concentration. However under medium to high [NOx] conditions (NOx > 1 ppbv), the effect on the chemistry due to the vertical distribution of the species means no box model can adequately represent chemistry in the NBL without modifying reaction rate constants
Henchir Bourgou (Djerba, Tunesien): Stratigraphie und Fundvorlage einer Sondage im Zentrum der antiken Siedlung (8. Jh. v. Chr. â 2. Jh. n. Chr.)
Die antike Siedlung Henchir Bourgou auf Djerba (Tunesien) ist seit 2017 Gegenstand gemeinsamer Forschungen des tunesischen Institut National du Patrimoine (INP) und des Deutschen ArchĂ€ologischen Instituts (DAI). Der vorliegende Beitrag ist die Publikation der Ergebnisse einer ersten Sondage im Zentrum des Siedlungsareals. Die Schichtenabfolge und die Baubefunde von den ersten Siedlungsphasen im 8. Jh. v. Chr. bis zu den letzten Spuren einer intensiven Besiedlung an der höchsten Stelle des Siedlungsareals in der letzten HĂ€lfte des 2. Jhs. n. Chr., geben gemeinsam mit der vorgelegten Fundkeramik und begleitenden naturwissenschaftlichen Untersuchungen einen ersten Ăberblick ĂŒber die Siedlungs- und Wirtschaftsgeschichte von Henchir Bourgou.The ancient settlement of Henchir Bourgou/Djerba (Tunisia) has been the focus of joint research by the Tunisian Institut National du Patrimoine (INP) and the German Archaeological Institute (DAI) since 2017. The article summarizes the results of a first sondage in the centre of the settlement area. The sequence of layers and the building features from the first settlement phases in the 8th century B.C. to the last traces of intensive occupation at the highest point of the settlement area in the last half of the 2nd century A.D., together with the find pottery and accompanying scientific investigations, provide a first overview of the settlement and economic history of Henchir Bourgou
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