947 research outputs found
The Impact of Positive Psychology on Change Readiness in Organization Development
Changes are imperative to organizations in today’s competitive and fast moving society. Organization development focuses on successful change strategies. The readiness level may affect employee change perception and behavior to allow for positive outcomes. The purpose of this research is to examine how various concepts of positive psychology such as the resources of psychological capital (PsyCap) impact employee readiness for change and how practitioners of organization development can benefit from the use of positive psychology in organizational change. Findings indicate that resources of psychological capital (PsyCap) such as hope, efficacy, resilience, and optimism positively influence change readiness and demonstrate positive change strategy for organizational change
Supernova Bounds on the Dark Photon Using its Electromagnetic Decay
The hypothetical massive dark photon () which has kinetic mixing
with the SM photon can decay electromagnetically to pairs if its mass
exceeds and otherwise into three SM photons. These decays yield
cosmological and supernovae associated signatures. We briefly discuss these
signatures, particularly in connection with the supernova SN1987A and delineate
the extra constraints that may then arise on the mass and mixing parameter of
the dark photon. In particular, we find that for dark photon mass
in the 5-20 MeV range, arguments based on supernova 1987A observations lead to
a bound on which is about 300 times stronger than the presently
existing bounds based on energy loss arguments.Comment: 10 pages, 6 figures, minor typos corrected, version to appear in NP
Age-Based Dynamics of a Stable Circulating Cd8 T Cell Repertoire Component
T-cell memory to pathogens can be envisioned as a receptor-based imprint of the pathogenic environment on the naive repertoire of clonotypes. Recurrent exposures to a pathogen inform and reinforce memory, leading to a mature state. The complexity and temporal stability of this system in man is only beginning to be adequately described. We have been using a rank-frequency approach for quantitative analysis of CD8 T cell repertoires. Rank acts as a proxy for previous expansion, and rank-frequency, the number of clonotypes at a particular rank, as a proxy for abundance, with the relation of the two estimating the diversity of the system. Previous analyses of circulating antigen-experienced cytotoxic CD8 T-cell repertoires from adults have shown a complex two-component clonotype distribution. Here we show this is also the case for circulating CD8 T cells expressing the BV19 receptor chain from five adult subjects. When the repertoire characteristic of clonotype stability is added to the analysis, an inverse correlation between clonotype rank frequency and stability is observed. Clonotypes making up the second distributional component are stable; indicating that the circulation can be a depot of selected clonotypes. Temporal repertoire dynamics was further examined for influenza-specific T cells from children, middle-aged, and older adults. Taken together, these analyses describe a dynamic process of system development and aging, with increasing distributional complexity, leading to a stable circulating component, followed by loss of both complexity and stability
Acute Changes in Sleep Duration on Eating Behaviors and Appetite-Regulating Hormones in Overweight/Obese Adults
There is considerable interest in the role of sleep in weight regulation, yet few studies have examined this relationship in overweight/obese (OW/OB) adults. Using a within-subject, counterbalanced design, 12 OW/OB women were studied in lab with two nights of short (5 hr time in bed [TIB]) and two nights of long (9 hr TIB) sleep. Hunger, consumption at a buffet, and fasting hormone levels were obtained. Significant polysomnographic differences occurred between conditions in total sleep time and sleep architecture (ps < .001). Percent energy from protein at the buffet increased following short sleep. No differences were observed for total energy intake or measured hormones. Further research is needed to determine how lengthening sleep impacts weight regulation in OW/OB adults
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Time-Resolved Imaging of Material Response Following Laser-Induced Breakdown in the Bulk and Surface of Fused Silica
Optical components within high energy laser systems are susceptible to laser-induced material modification when the breakdown threshold is exceeded or damage is initiated by pre-existing impurities or defects. These modifications are the result of exposure to extreme conditions involving the generation of high temperatures and pressures and occur on a volumetric scale of the order of a few cubic microns. The response of the material following localized energy deposition, including the timeline of events and the individual processes involved during this timeline, is still largely unknown. In this work, we investigate the events taking place during the entire timeline in both bulk and surface damage in fused silica using a set of time-resolved microscopy systems. These microscope systems offer up to 1 micron spatial resolution when imaging static or dynamic effects, allowing for imaging of the entire process with adequate temporal and spatial resolution. These systems incorporate various pump-probe geometries designed to optimize the sensitivity for detecting individual aspects of the process such as the propagation of shock waves, near-surface material motion, the speed of ejecta, and material transformations. The experimental results indicate that the material response can be separated into distinct phases, some terminating within a few tens of nanoseconds but some extending up to about 100 microseconds. Overall the results demonstrate that the final characteristics of the modified region depend on the material response to the energy deposition and not on the laser parameters
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A new expedited approach to evaluate the importance of different crystal growth parameters on laser damage performance in KDP and DKDP
In this work, we investigate the laser-induced damage resistance at 355 nm in DKDP crystals grown with varying growth parameters, including temperature, speed of growth and impurity concentration. In order to perform this work, a DKDP crystal was grown over 34 days by the rapid-growth technique with varied growth conditions. By using the same crystal, we are able to isolate growth-related parameters affecting LID from raw material or other variations that are encountered when testing in different crystals. The objective is to find correlations of damage performance to growth conditions and reveal the key parameters for achieving DKDP material in which the number of damage initiating defects is reduced. This approach can lead to reliable and expedite information regarding the importance of different crystal growth parameters on the laser damage characteristics of these crystals
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Electronic Structure Calculations of an Oxygen Vacancy in KH2PO4
We present first-principles total-energy density-functional theory electronic structure calculations for the neutral and charge states of an oxygen vacancy in KH{sub 2}PO{sub 4} (KDP). Even though the overall DOS profiles for the defective KDP are quite similar to those of the perfect KDP, the oxygen vacancy in the neutral and +1 charge states induces defect states in the band gap. For the neutral oxygen vacancy, the gap states are occupied by two electrons. The difference between the integral of the total density of states (DOS) and the sum of the DOS projected on the atoms of 0.98 |e|, indicates that one of the two electrons resulting from the removal of the oxygen atom is trapped in the vacancy, while the other tends to delocalize in the neighboring atoms. For the +1 charge oxygen vacancy, the addition of the hole reduces the occupation of the filled gap-states in the neutral case from two to one electron and produces new empty states in the gap. The new empty gap states are very close to the highest occupied states, leading to a dramatic decrease of the band gap. The difference between the integral of the total DOS and the sum of the DOS projected on the atoms is 0.56 |e|, which implies that more than 56% of the redundant electron is trapped in the oxygen vacancy, and 44% spreads over the neighboring atoms. In sharp contrast, no defect states appear in the energy gap for the +2 charge O vacancy. Thus, the addition of the two holes completely compensates the two redundant electrons, and removes in turn the occupied gap states in the neutral case
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Autofluorescence dynamics during reperfusion following long-term renal ischemia in a rat model
Optical properties of near-surface kidney tissue were monitored in order to assess response during reperfusion to long (20 minutes) versus prolonged (150 minutes) ischemia in an in vivo rat model. Specifically, autofluorescence images of the exposed surfaces of both the normal and the ischemic kidneys were acquired during both injury and reperfusion alternately under 355 nm and 266 nm excitations. The temporal profile of the emission of the injured kidney during the reperfusion phase under 355 nm excitation was normalized to that under 266 nm as a means to account for changes in tissue optical properties independent of ischemia as well as changes in the illumination/collection geometrical parameters in future clinical implementation of this technique using a hand-held probe. The scattered excitation light signal was also evaluated as a reference signal and found to be inadequate. Characteristic time constants were extracted using fit to a relaxation model and found to have larger mean values following 150 minutes of injury. The mean values were then compared with the outcome of a chronic survival study where the control kidney had been removed. Rat kidneys exhibiting longer time constants were much more likely to fail. This may lead to a method to assess kidney viability and predict its ability to recover in the initial period following transplantation or resuscitation
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The role of phase instabilities in the early material response during laser-induced breakdown in bulk fused silica
Comparative Outcomes of Commonly Used Off-Label Atypical Antipsychotics in the Treatment of Dementia-Related Psychosis: A Network Meta-Analysis
Introduction
Dementia-related psychosis (DRP) is characterized by hallucinations and delusions, which may increase the debilitating effects of underlying dementia. This network meta-analysis (NMA) evaluated the comparative efficacy, safety, and acceptability of atypical antipsychotics (AAPs) commonly used off label to treat DRP. Methods
We included 22 eligible studies from a systematic literature review of AAPs (quetiapine, risperidone, olanzapine, aripiprazole, and brexpiprazole) used off label to treat DRP. Study outcomes were: (1) efficacy—neuropsychiatric inventory-nursing home (NPI-NH psychosis subscale), (2) safety—mortality, cerebrovascular events (CVAEs), and others (somnolence, falls, fractures, injuries, etc.), and (3) acceptability—discontinuations due to all causes, lack of efficacy, and adverse events (AEs). We used random-effects modeling to estimate pooled standardized mean differences (SMDs) for NPI-NH psychosis subscale scores and odds ratios (OR) for other dichotomous outcomes, with their respective 95% confidence intervals (CIs). Results
Compared with placebo, aripiprazole (SMD − 0.12; 95% CI − 0.31, 0.06), and olanzapine (SMD − 0.17; 95% CI − 0.04; 0.02) demonstrated small, non-significant numerical improvements in NPI-NH psychosis scores (5 studies; n = 1891), while quetiapine (SMD 0.04; 95% CI − 0.23, 0.32) did not improve symptoms. The odds of mortality (15 studies, n = 4989) were higher for aripiprazole (OR 1.58; 95% CI 0.62, 4.04), brexpiprazole (OR 2.22; 95% CI 0.30, 16.56), olanzapine (OR 2.21; 95% CI 0.84, 5.85), quetiapine (OR 1.68; 95% CI 0.70, 4.03), and risperidone (OR 1.63; 95% CI 0.93, 2.85) than for placebo. Risperidone (OR 3.68; 95% CI 1.68, 8.95) and olanzapine (OR 4.47; 95% CI 1.36, 14.69) demonstrated significantly greater odds of CVAEs compared to placebo. Compared with placebo, odds of all-cause discontinuation were significantly lower for aripiprazole (OR 0.71; 95% CI 0.51, 0.98; 20 studies; 5744 patients) and higher for other AAPs. Aripiprazole (OR 0.5; 95% CI 0.31, 0.82) and olanzapine (OR 0.48; 95% CI 0.31, 0.74) had significantly lower odds of discontinuation due to lack of efficacy (OR 12 studies; n = 4382) compared to placebo, while results for quetiapine and risperidone were not significant. Compared with placebo, the odds of discontinuation due to AEs (19 studies, n = 5445) were higher for olanzapine (OR 2.62; 95% CI 1.75, 3.92), brexpiprazole (OR 1.80; 95% CI 0.80, 4.07), quetiapine (OR 1.25; 95% CI 0.82, 1.91), aripiprazole (OR 1.38; 95% CI 0.90, 2.13), and risperidone (OR 1.41; 95% CI 1.02, 1.94). Conclusions
Overall results demonstrate that, compared with placebo, quetiapine is not associated with improvement in psychosis in patients with dementia, while olanzapine and aripiprazole have non-significant small numerical improvements. These off-label AAPs (quetiapine, risperidone, olanzapine, aripiprazole, and brexpiprazole) are associated with greater odds of mortality, CVAEs, and discontinuations due to AEs than placebo. These results underscore the ongoing unmet need for newer pharmacological options with a more favorable benefit-risk profile for the treatment of DRP
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