86 research outputs found

    Observed photodetachment in parallel electric and magnetic fields

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    We investigate photodetachment from negative ions in a homogeneous 1.0-T magnetic field and a parallel electric field of approximately 10 V/cm. A theoretical model for detachment in combined fields is presented. Calculations show that a field of 10 V/cm or more should considerably diminish the Landau structure in the detachment cross section. The ions are produced and stored in a Penning ion trap and illuminated by a single-mode dye laser. We present preliminary results for detachment from S- showing qualitative agreement with the model. Future directions of the work are also discussed.Comment: Nine pages, five figures, minor revisions showing final publicatio

    Age- and sex-specific physical fitness reference and association with body mass index in Hong Kong Chinese schoolchildren

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    There is lacking a population-based study on the fitness level of Hong Kong schoolchildren, and it seems that increasing childhood obesity prevalence has shifted the classification of healthy fitness, with ‘underfit’ as normal. This cross-sectional territory study aimed to develop an age- and sex-specific physical fitness reference using a representative sample of children aged 6–17 and to determine the associations with body mass index in schoolchildren. The study analyzed Hong Kong School Physical Fitness Award Scheme data covering grade 1 to grade 12 students’ physical fitness and anthropometric measurements from 2017 to 2018. This reference was established without the impact due to COVID-19. Four aspects of physical fitness tests were measured using a standardized protocol, including (i) upper limb muscle strength, (ii) one-minute sit-up, (iii) sit-and-reach, and (iv) endurance run tests. The generalized additive model for location, scale, and shape was used to construct the reference charts. A Mann–Whitney U test was used to compare the mean differences in age, weight, and height, and a Pearson’s chi-square test was used to examine the distributions of sex groups. A Kruskal–Wallis test was used to compare the group differences in BMI status, followed by the Dunn test for pairwise comparisons. A 5% level of significance was regarded as statistically significant. Data of 119,693 students before the COVID-19 pandemic were included in the analysis. The association between physical fitness level and BMI status varied depending on the test used, and there were significant differences in fitness test scores among BMI groups. The mean test scores of the obese group were lower in most of the tests for both boys and girls, except for handgrip strength. The underweight group outperformed the obese group in push-ups, one-minute sit-ups, and endurance run tests, but not in handgrip strength. In conclusion, a sex- and age-specific physical fitness reference value for Hong Kong Chinese children aged 6 to 17 years old is established, and this study demonstrated a nonlinear relationship between BMI status and physical fitness. The reference will help to identify children with poor physical fitness to offer support and guidance on exercise training. It also serves as a baseline for assessing the impact of the COVID-19 pandemic on Hong Kong students’ physical fitness

    Modeling Microstructure and Irradiation Effects

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    Photochemistry of p-nitroacetophenone in 2-propanol

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    Upon irradiation in 2-propanol, p-nitroacetophenone 1 was reduced via the triplet state to p-hydroxyaminoacetophenone 5 which was further reduced to p-aminoacetophenone 2 and 4,4'-diacetylazobenzene 4. Similar irradiation of 5 also Save 2 and 4, and its oxidation by oxygen Save 4,4'-diacetylazoxybenzene 3. Photolysis of monomeric p-nitrosoacetophenone 6 afforded acetophenone and 3 that were not produced during the irradiation of 1. Possible photoreaction pathways were discussed on the basis of published mechanisms

    The association between multimorbidity and poor adherence with cardiovascular medications

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    Multimorbidity, defined as the presence of two or more chronic conditions, leads to a substantial public health burden. This study evaluated its association with adherence with cardiovascular medications in a Chinese population. A proportional stratified sampling was adopted to draw a representative sample of residents living in Henan Province, China. Interviewer-administered surveys were conducted by trained researchers. The outcomes included the number of chronic medical conditions, adherence with long-term medications (MMAS-8), and depressive symptoms (CESD-20). Binary logistic regression analysis was conducted to evaluate if medication adherence was associated with the presence of multimorbidity. From a total of 3866 completed surveys, the proportion of subjects having 0, 1 and ≥ 2 chronic conditions was 62.6%, 23.8% and 13.5%, respectively. Among 27.6% who were taking chronic medications, 66.6% had poor medication adherence (MMAS-8 score ≤ 6). From binary logistic regression analysis, subjects with poor medication adherence were significantly associated with multimorbidity (adjusted odds ratio [AOR]: 1.35, 95% C.I. 1.02–1.78, p = 0.037). Other associated factors included older age (AOR = 1.04, 95% C.I. 1.03–1.05, p < 0.001), smoking (AOR = 1.63, 95% C.I. 1.16–2.30, p = 0.005), family history of hypertension (AOR = 1.51, 95% C.I. 1.19–1.93, p = 0.001), and fair to poor self-perceived health status (AOR = 2.15, 95% C.I. 1.69–2.74, p < 0.001). Using medication adherence as the outcome variable, multimorbidity was significantly associated with poor drug adherence (AOR = 1.34, 95% C.I. 1.02–1.77, p = 0.037). Multimorbidity was associated with poorer medication adherence. This implies the need for closer monitoring of the medication taking behavior among those with multiple chronic conditions

    Pulsatile flow investigation in development of thoracic aortic aneurysm: An in-vitro validated fluid structure interaction analysis

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    10.29252/JAFM.12.06.29769Journal of Applied Fluid Mechanics1261855-187
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