1,546 research outputs found
Mass transfer and gas-liquid interface properties of single CO2 bubbles rising in tap water
To improve the mass transfer efficiency in many industrial applications better understanding of the mass transfer rate is required. High speed images of single CO2 bubbles rising in tap water were analysed to investigate the relationship between the mass transfer and properties of single bubbles. Transition to a lower mass transfer rate was shown to correspond with the transition from a mobile to an immobile bubble surface. This was indicated by the change in bubble rise velocity, bubble rise path and bubble shape. The presence of surfactants in untreated tap water appear to effect the transition point, particularly for bubbles with a smaller initial diameter and lower rise velocity
A functional analysis of two transdiagnostic, emotion-focused interventions on nonsuicidal self-injury
OBJECTIVE: Nonsuicidal self-injury (NSSI) is prevalent and associated with clinically significant consequences. Developing time-efficient and cost-effective interventions for NSSI has proven difficult given that the critical components for NSSI treatment remain largely unknown. The aim of this study was to examine the specific effects of mindful emotion awareness training and cognitive reappraisal, 2 transdiagnostic treatment strategies that purportedly address the functional processes thought to maintain self-injurious behavior, on NSSI urges and acts.
METHOD: Using a counterbalanced, combined series (multiple baseline and data-driven phase change) aggregated single-case experimental design, the unique and combined impact of these 2 4-week interventions was evaluated among 10 diagnostically heterogeneous self-injuring adults. Ecological momentary assessment was used to provide daily ratings of NSSI urges and acts during all study phases.
RESULTS: Eight of 10 participants demonstrated clinically meaningful reductions in NSSI; 6 participants responded to 1 intervention alone, whereas 2 participants responded after the addition of the alternative intervention. Group analyses indicated statistically significant overall effects of study phase on NSSI, with fewer NSSI urges and acts occurring after the interventions were introduced. The interventions were also associated with moderate to large reductions in self-reported levels of anxiety and depression, and large improvements in mindful emotion awareness and cognitive reappraisal skills.
CONCLUSIONS: Findings suggest that brief mindful emotion awareness and cognitive reappraisal interventions can lead to reductions in NSSI urges and acts. Transdiagnostic, emotion-focused therapeutic strategies delivered in time-limited formats may serve as practical yet powerful treatment approaches, especially for lower-risk self-injuring individuals.Dr. Barlow receives royalties from Oxford University Press, Guilford Publications Inc., Cengage Learning, and Pearson Publishing. Grant monies for various projects come from the National Institute of Mental Health (F31MH100761), the National Institute of Alcohol and Alcohol Abuse, and Colciencias (Government of Columbia Initiative for Science, Technology, and Health Innovation). Consulting and honoraria during the past several years have come from the Agency for Healthcare Research and Quality, the Foundation for Informed Medical Decision Making, the Department of Defense, the Renfrew Center, the Chinese University of Hong Kong, Universidad Catolica de Santa Maria (Arequipa, Peru), New Zealand Psychological Association, Hebrew University of Jerusalem, Mayo Clinic, and various American Universities. (F31MH100761 - National Institute of Mental Health; National Institute of Alcohol and Alcohol Abuse; Colciencias (Government of Columbia Initiative for Science, Technology, and Health Innovation))Accepted manuscrip
Evaluating aggregate effects of rare and common variants in the 1000 Genomes Project exon sequencing data using latent variable structural equation modeling
Methods that can evaluate aggregate effects of rare and common variants are limited. Therefore, we applied a two-stage approach to evaluate aggregate gene effects in the 1000 Genomes Project data, which contain 24,487 single-nucleotide polymorphisms (SNPs) in 697 unrelated individuals from 7 populations. In stage 1, we identified potentially interesting genes (PIGs) as those having at least one SNP meeting Bonferroni correction using univariate, multiple regression models. In stage 2, we evaluate aggregate PIG effects on trait, Q1, by modeling each gene as a latent construct, which is defined by multiple common and rare variants, using the multivariate statistical framework of structural equation modeling (SEM). In stage 1, we found that PIGs varied markedly between a randomly selected replicate (replicate 137) and 100 other replicates, with the exception of FLT1. In stage 1, collapsing rare variants decreased false positives but increased false negatives. In stage 2, we developed a good-fitting SEM model that included all nine genes simulated to affect Q1 (FLT1, KDR, ARNT, ELAV4, FLT4, HIF1A, HIF3A, VEGFA, VEGFC) and found that FLT1 had the largest effect on Q1 (Ī²std = 0.33 Ā± 0.05). Using replicate 137 estimates as population values, we found that the mean relative bias in the parameters (loadings, paths, residuals) and their standard errors across 100 replicates was on average, less than 5%. Our latent variable SEM approach provides a viable framework for modeling aggregate effects of rare and common variants in multiple genes, but more elegant methods are needed in stage 1 to minimize type I and type II error
Venus Interior Structure Mission (VISM): Establishing a Seismic Network on Venus
Magellan radar data show the surface of Venus to contain a wide range of geologic features (large volcanoes, extensive rift valleys, etc.). Although networks of interconnecting zones of deformation are identified, a system of spreading ridges and subduction zones like those that dominate the tectonic style of the Earth do not appear to be present. In addition, the absence of a mantle low-viscosity zone suggests a strong link between mantle dynamics and the surface. As a natural follow-on to the Magellan mission, establishing a network of seismometers on Venus will provide detailed quantitative information on the large scale interior structure of the planet. When analyzed in conjunction with image, gravity, and topography information, these data will aid in constraining mechanisms that drive surface deformation
Modeling the Pinning of Au and Ni Clusters on Graphite
The pinning of size-selected AuN and NiN clusters on graphite, for N=7ā100, is investigated by means of molecular dynamics simulations and the results are compared to experiment and previous work with Ag clusters. Ab initio calculations of the binding of the metal adatom and dimers on a graphite surface are used to parametrize the potentials used in the simulations. The clusters are projected normally towards a graphite surface and the value of the energy at which pinning first occurs, EP, is determined. Pinning is shown to occur when a surface defect, made by the cluster interaction, is first produced. The simulations give a good agreement with the experimentally determined pinning energy thresholds and the heights of the clusters on the surface. The gold clusters are shown to be flatter and more spread out than the nickel clusters which are more compact
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Effects of Intravenous Ketamine on Explicit and Implicit Measures of Suicidality in Treatment-Resistant Depression
Background
Intravenous ketamine has shown rapid antidepressant effects in early trials, making it a potentially attractive candidate for depressed patients at imminent risk of suicide. The Implicit Association Test (IAT), a performance-based measure of association between concepts, may have utility in suicide assessment.
Methods
Twenty-six patients with treatment-resistant depression were assessed using the suicidality item of the Montgomery-Asberg Depression Rating Scale (MADRS-SI) 2 hours before and 24 hours following a single subanesthetic dose of intravenous ketamine. Ten patients also completed IATs assessing implicit suicidal associations at comparable time points. In a second study, nine patients received thrice-weekly ketamine infusions over a 12-day period.
Results
Twenty-four hours after a single infusion, MADRS-SI scores were reduced on average by 2.08 points on a 0 to 6 scale (p < .001; d = 1.37), and 81% of patients received a rating of 0 or 1 postinfusion. Implicit suicidal associations were also reduced following ketamine (p = .003; d = 1.36), with reductions correlated across implicit and explicit measures. MADRS-SI reductions were sustained for 12 days by repeated-dose ketamine (p < .001; d = 2.42).
Conclusions
These preliminary findings support the premise that ketamine has rapid beneficial effects on suicidal cognition and warrants further study.Psycholog
Why alternative teenagers self-harm: exploring the link between non-suicidal self-injury, attempted suicide and adolescent identity
Background:
The term āself-harmā encompasses both attempted suicide and non-suicidal self-injury (NSSI). Specific adolescent subpopulations such as ethnic or sexual minorities, and more controversially, those who identify as āAlternativeā (Goth, Emo) have been proposed as being more likely to self-harm, while other groups such as āJocksā are linked with protective coping behaviours (for example exercise). NSSI has autonomic (it reduces negative emotions) and social (it communicates distress or facilitates group ābondingā) functions. This study explores the links between such aspects of self-harm, primarily NSSI, and youth subculture.<p></p>
Methods:
An anonymous survey was carried out of 452 15 year old German school students. Measures included: identification with different youth cultures, i.e. Alternative (Goth, Emo, Punk), Nerd (academic) or Jock (athletic); social background, e.g. socioeconomic status; and experience of victimisation. Self-harm (suicide and NSSI) was assessed using Self-harm Behavior Questionnaire and the Functional Assessment of Self-Mutilation (FASM).<p></p>
Results:
An āAlternativeā identity was directly (rāāā0.3) and a āJockā identity inversely (rāāā-0.1) correlated with self-harm. āAlternativeā teenagers self-injured more frequently (NSSI 45.5% vs. 18.8%), repeatedly self-injured, and were 4ā8 times more likely to attempt suicide (even after adjusting for social background) than their non-Alternative peers. They were also more likely to self-injure for autonomic, communicative and social reasons than other adolescents.<p></p>
Conclusions:
About half of āAlternativeā adolescentsā self-injure, primarily to regulate emotions and communicate distress. However, a minority self-injure to reinforce their group identity, i.e. āTo feel more a part of a groupā
Experimental characterization of universal one-way quantum computing
We report the characterization of a universal set of logic gates for one-way quantum computing using a four-photon 'star' cluster state generated by fusing photons from two independent photonic crystal fibre sources. We obtain a fidelity for the cluster state of 0.66 Ā± 0.01 with respect to the ideal case. We perform quantum process tomography to completely characterize a controlled-NOT, Hadamard and T gate all on the same compact entangled resource. Together, these operations make up a universal set of gates such that arbitrary quantum logic can be efficiently constructed from combinations of them. We find process fidelities with respect to the ideal cases of 0.64 Ā± 0.01 for the CNOT, 0.67 Ā± 0.03 for the Hadamard and 0.76 Ā± 0.04 for the T gate. The characterization of these gates enables the simulation of larger protocols and algorithms. As a basic example, we simulate a Swap gate consisting of three concatenated CNOT gates. Our work provides some pragmatic insights into the prospects for building up to a fully scalable and fault-tolerant one-way quantum computer with photons in realistic conditions
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