2,170 research outputs found
Rotating Black Holes and Coriolis Effect
In this work, we consider the fluid/gravity correspondence for general
rotating black holes. By using the Petrov-like boundary condition in near
horizon limit, we study the correspondence between gravitational perturbation
and fluid equation. We find that the dual fluid equation for rotating black
holes contains a Coriolis force term, which is closely related to the angular
velocity of the black hole horizon. This can be seen as a dual effect for the
frame-dragging effect of rotating black hole under the holographic picture.Comment: 5 page
Surface Hardening of Ti-15V-3Al-3Cr-3Sn Alloy after Cyclic Hydrogenation and Subsequent Solution Treatment
The as-received and preheated (1000°C-30 min. and 500°C-30 min.) sheets of Ti-15V-3Al-3Cr-3Sn alloy (Ti-153) were treated according to the predetermined process including a cyclic electrolytic hydrogenation (at 50 mA/cm2 for 1 hr and at 5 mA/cm2 for 10 hrs) combining a subsequent solution treatment to see the effects of various operating parameters on the evolution of microstructure and the variations of hardness. The hardening effect deriving from solid-solution strengthening of hydrogen eventually overrode that from precipitation hardening. The maximum hardness elevation was from 236.9 to 491.1 VHN
Gratitude and athletes’ life satisfaction: a intra-individual analysis on the moderation of ambivalence over emotional expression
Research on gratitude usually focus on how trait gratitude can contribute to higher subjective well-being, but rarely focus on the role of state gratitude in shaping one’s subjective well-being at a given moment. Focusing on intra-individual differences, the first aim of this study is to examine whether state gratitude will contribute to higher state life satisfaction. Nevertheless, state gratitude may not always contribute to higher state life satisfaction. The second aim of this study is to determinate that when ambivalence over emotional expression in a given moment becomes higher, the association between state gratitude and state life satisfaction will become weaker. Twenty-nine elite student athletes were recruited and completed weekly questionnaires measuring gratitude, life satisfaction, and ambivalence over emotional expression across 10 weeks. Results of hierarchical linear modeling support hypotheses, showing that weekly gratitude positively predicted weekly life satisfaction, but this association was weaker when weekly ambivalence over emotional expression was higher than lower. Contributions to gratitude studies are discussed
Unpacking the role of self-esteem in career uncertainty: a self-determination perspective
The aim of this study is to explain why students with high self-esteem have lower career uncertainty than students with low self-esteem. Based on self-determination theory, students with high self-esteem would have higher efficacy in making decisions, which would encourage them to choose a major for self-concordance, such as interest and ability, and increase their course involvement. Both factors are assumed to be related to lower career uncertainty. Data from a national survey of the Taiwan Higher Education Database within the Survey Research Data Archive from juniors at 92 colleges and universities in Taiwan (N = 7418) were analyzed to examine the model. Results supported the proposed model by showing that students with high self-esteem had lower career uncertainty because they chose a major for self-concordant reasons and had a strong motivation to learn, both of which contribute to lower career uncertainty
Methylation at the C-2 position of hopanoids increases rigidity in native bacterial membranes
Sedimentary rocks host a vast reservoir of organic carbon, such as 2-methylhopane biomarkers, whose evolutionary significance we poorly understand. Our ability to interpret this molecular fossil record is constrained by ignorance of the function of their molecular antecedents. To gain insight into the meaning of 2-methylhopanes, we quantified the dominant (des)methylated hopanoid species in the membranes of the model hopanoid-producing bacterium Rhodopseudomonas palustris TIE-1. Fluorescence polarization studies of small unilamellar vesicles revealed that hopanoid 2-methylation specifically renders native bacterial membranes more rigid at concentrations that are relevant in vivo. That hopanoids differentially modify native membrane rigidity as a function of their methylation state indicates that methylation itself promotes fitness under stress. Moreover, knowing the in vivo (2Me)-hopanoid concentration range in different cell membranes, and appreciating that (2Me)-hopanoids' biophysical effects are tuned by the lipid environment, permits the design of more relevant in vitro experiments to study their physiological functions
Gratitude and Athletes’ Life Satisfaction: The Moderating Role of Mindfulness
Life satisfaction is a critical index of well-being and is well documented in the literature as a means of protecting athletes from stress. However, minimal research has focused on the factors that contribute to life satisfaction in sports. Accordingly, we adopted the positive psychology perspective and proposed that gratitude would relate to athletes’ life satisfaction. Additionally, we further suggested that mindfulness would strengthen the relationship between gratitude and athletes’ life satisfaction. Athletes completed measurements, and the results, which indicated that athletes with higher levels of gratitude exhibited increased life satisfaction when they had higher levels of mindfulness, supported our expectations. The implications and applications are discussed in terms of mindfulness
Note on a Single-Machine Scheduling Problem with Sum of Processing Times Based Learning and Ready Times
In the recent 20 years, scheduling with learning effect has received considerable attention. However, considering the learning effect along with release time is limited. In light of these observations, in this paper, we investigate a single-machine problem with sum of processing times based learning and ready times where the objective is to minimize the makespan. For solving this problem, we build a branch-and-bound algorithm and a heuristic algorithm for the optimal solution and near-optimal solution, respectively. The computational experiments indicate that the branch-and-bound algorithm can perform well the problem instances up to 24 jobs in terms of CPU time and node numbers, and the average error percentage of the proposed heuristic algorithm is less than 0.5%
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