643 research outputs found
Eisenhart Lift of --Dimensional Mechanics
The Eisenhart lift is a variant of geometrization of classical mechanics with
degrees of freedom in which the equations of motion are embedded into the
geodesic equations of a Brinkmann-type metric defined on -dimensional
spacetime of Lorentzian signature. In this work, the Eisenhart lift of
-dimensional mechanics on curved background is studied. The corresponding
-dimensional metric is governed by two scalar functions which are just the
conformal factor and the potential of the original dynamical system. We derive
a conformal symmetry and a corresponding quadratic integral, associated with
the Eisenhart lift. The energy--momentum tensor is constructed which, along
with the metric, provides a solution to the Einstein equations. Uplifts of
-dimensional superintegrable models are discussed with a particular emphasis
on the issue of hidden symmetries. It is shown that for the -dimensional
Darboux--Koenigs metrics, only type I can result in Eisenhart lifts which
satisfy the weak energy condition. However, some physically viable metrics with
hidden symmetries are presented.Comment: 20 page
Response inhibition deficits are positively associated with trait rumination, but attentional inhibition deficits are not : aggressive behaviors and interpersonal stressors as mediators
Previous findings on relationships between inhibition that is a core executive function, and trait rumination have been inconsistent. This inconsistency could be overcome by investigating the association between rumination and the two subcomponents of inhibition: response inhibition and attentional inhibition. This study examined whether and how response inhibition and attentional inhibition were related to rumination as well as worry. University students in Japan (N = 213) conducted the Go/No-Go Task and the Modified Stroop Task. They also completed self-report measures of depression, trait rumination, trait worry, stressors, and aggressive behaviors. Results indicated that response inhibition deficits were positively associated with trait rumination, and this association was mediated by increases in aggressive behaviors and interpersonal stressors. The associations between these variables remained significant even after controlling for depression level. There were no significant direct or indirect associations between attentional inhibition deficits and rumination. These results suggest that response inhibition deficits, among the subcomponents of inhibition, have an indirect positive association with rumination through interpersonal processes. Results also showed nonsignificant differences between rumination and worry in the magnitude of correlation coefficients with the two subcomponents of inhibition. Therefore, it remains unclear whether the positive association with response inhibition is unique to rumination
Assessment of inhibition with the Go/No-Go Task
Young, Sutherland, and McCoy indicated that a Go/No-Go Task (GNG) becomes more difficult as the inter-stimulus intervals (ISIs) becomes shorter. However, is the number of commission errors under extremely short ISIs a useful metric for assessing response inhibition? This study challenges the assumption that a shorter ISI in the GNG enables better assessment of response inhibition. University students (N = 213) completed the GNG, the Conners Continuous Performance Test 3rd Edition (CCPT), and the Modified Stroop Task. The GNG comprised four blocks of 400, 600, 800, and 1000 ms ISIs, whereas the stimulus presentation was fixed at 250 ms. Consistent with Young et al., shorter ISIs in the GNG resulted in more commission errors. In the block with the shortest ISI, participants also failed more frequently in responses in go trials than in the other blocks, which appears to increase in error variance of commission errors. Consistent with this interpretation, the association between the number of commission errors in the block with 400 ms ISI and CCPT performance was weaker than those between the number of commission errors in other blocks and CCPT performance. It is concluded that using the number of commission errors in the condition with extremely short ISIs in the GNG might be inappropriate for assessing response inhibition
Obesity and Cardiovascular Risk After Quitting Smoking: The Latest Evidence
Smoking cessation is one of the most effective ways to reduce cardiovascular risk. However, weight gain and abdominal obesity generally occur after quitting smoking, as a result of nicotine withdrawal. Obesity increases various inflammatory markers, and weight gain after smoking cessation temporarily increases the risk of diabetes and reduces the benefit gained by smoking abstinence. The benefits of smoking cessation may be minimised by obesity in those who have stopped smoking. Pharmacological treatment with medications such as nicotine patches and varenicline is useful to suppress weight gain during smoking cessation. Supporting patients to continue smoking cessation and to gradually decrease their weight will be crucial
Causes and consequences of stress generation : Longitudinal associations of negative events, aggressive behaviors, rumination, and depressive symptoms
The present study examined the causes and consequences of stress generation in university students in Japan. A two-wave longitudinal study with an 8- or 9-week interval was conducted in the fall of 2020. Undergraduate and graduate students at four universities in Japan (N = 201) completed self-report measures assessing experiences of negative interpersonal dependent events, negative non-interpersonal events, and negative independent events at two times. At the same time, they also responded to measures of aggressive behaviors, trait rumination, and depressive symptoms. Path analyses revealed that baseline aggressive behaviors were positively associated with an increase in subsequent negative interpersonal dependent events, even after controlling for the influences of negative interpersonal dependent events, rumination, and depressive symptoms at baseline. However, aggressive behaviors were not significantly associated with subsequent negative non-interpersonal dependent events or negative independent events. These findings suggest that aggressive behaviors may have been a factor leading to interpersonal stress generation. Furthermore, all categories of negative event experiences predicted an increase in subsequent depressive symptoms, but not subsequent rumination, and rumination was not significantly associated with subsequent depressive symptoms. This research extends previous studies on the causes and consequences of stress generation conducted in the US by using specific measures of aggressive behaviors and including a non-restricted sample of university students in Japan
Selected Mutations in a Mesophilic Cytochrome c Confer the Stability of a Thermophilic Counterpart
Mesophilic cytochrome c551 of Pseudomonas aeruginosa (PA c551) became as stable as its thermophilic counterpart, Hydrogenobacter thermophilus cytochrome c552 (HT c552), through only five amino acid substitutions. The five residues, distributed in three spatially separated regions, were selected and mutated with reference to the corresponding residues in HT c552 through careful structure comparison. Thermodynamic analysis indicated that the stability of the quintuple mutant of PA c551 could be partly attained through an enthalpic factor. The solution structure of the mutant showed that, as in HT c552, there were tighter side chain packings in the mutated regions. Furthermore, the mutant had an increased total accessible surface area, resulting in great negative hydration free energy. Our results provide a novel example of protein stabilization in that limited amino acid substitutions can confer the overall stability of a natural highly thermophilic protein upon a mesophilic molecule.This work was supported by a grant from the Japanese Ministry of Education, Science and Culture
Artificial neural network approach for selection of susceptible single nucleotide polymorphisms and construction of prediction model on childhood allergic asthma
BACKGROUND: Screening of various gene markers such as single nucleotide polymorphism (SNP) and correlation between these markers and development of multifactorial disease have previously been studied. Here, we propose a susceptible marker-selectable artificial neural network (ANN) for predicting development of allergic disease. RESULTS: To predict development of childhood allergic asthma (CAA) and select susceptible SNPs, we used an ANN with a parameter decreasing method (PDM) to analyze 25 SNPs of 17 genes in 344 Japanese people, and select 10 susceptible SNPs of CAA. The accuracy of the ANN model with 10 SNPs was 97.7% for learning data and 74.4% for evaluation data. Important combinations were determined by effective combination value (ECV) defined in the present paper. Effective 2-SNP or 3-SNP combinations were found to be concentrated among the 10 selected SNPs. CONCLUSION: ANN can reliably select SNP combinations that are associated with CAA. Thus, the ANN can be used to characterize development of complex diseases caused by multiple factors. This is the first report of automatic selection of SNPs related to development of multifactorial disease from SNP data of more than 300 patients
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