258 research outputs found

    On the Propagation of a Geoeffective Coronal Mass Ejection during March 15 -- 17, 2015

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    The largest geomagnetic storm so far in the solar cycle 24 was produced by a fast coronal mass ejection (CME) originating on 2015 March 15. It was an initially west-oriented CME and expected to only cause a weak geomagnetic disturbance. Why did this CME finally cause such a large geomagnetic storm? We try to find some clues by investigating its propagation from the Sun to 1 AU. First, we reconstruct the CME's kinematic properties in the corona from the SOHO and SDO imaging data with the aid of the graduated cylindrical shell (GCS) model. It is suggested that the CME propagated to the west ∼\sim33∘33^\circ±\pm10∘10^\circ away from the Sun-Earth line with a speed of about 817 km s−1^{-1} before leaving the field of view of the SOHO/LASCO C3 camera. A magnetic cloud (MC) corresponding to this CME was measured in-situ by the Wind spacecraft two days later. By applying two MC reconstruction methods, we infer the configuration of the MC as well as some kinematic information, which implies that the CME possibly experienced an eastward deflection on its way to 1 AU. However, due to the lack of observations from the STEREO spacecraft, the CME's kinematic evolution in interplanetary space is not clear. In order to fill this gap, we utilize numerical MHD simulation, drag-based CME propagation model (DBM) and the model for CME deflection in interplanetary space (DIPS) to recover the propagation process, especially the trajectory, of the CME from 30RS30 R_S to 1 AU. It is suggested that the trajectory of the CME was deflected toward the Earth by about 12∘12^\circ, consistent with the implication from the MC reconstruction at 1 AU. This eastward deflection probably contributed to the CME's unexpected geoeffectiveness by pushing the center of the initially west-oriented CME closer to the Earth.Comment: 10 pages, 5 figures, 1 table, accepted by JGR - Space Physic

    Antecedents of attitude and their impact on behavioral intention in the staycation context

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    The year 2020 and 2021 have been decimated by the pandemic, leading to outbound vacations largely scrapped. Staycation, a typical domestic journal, has then been adopted by those who are tired of self-isolation for so long. This study aims to explore and assess the drivers exerting impact on attitude of tourists toward staycation and the interrelationship among the research constructs is also examined. A quantitative analysis is employed for evaluating the roles of reduced risk perception, benign envy, and perceived benefits as they exert the effect on attitude toward staycation. An online questionnaire survey was used, and a total of 213 samples were collected from target respondents in Hong Kong, which were still under lockdown at the time of the study. The results of the study showed that reduced risk perception, benign envy as well as perceived benefits will influence tourists’ attitude toward staycation. The managerial and theoretical implications of the results are discussed based on the significant relationships identified in the study

    Multiplex PCR for 17 Y-Chromosome Specific Short Tandem Repeats (STR) to Enhance the Reliability of Fetal Sex Determination in Maternal Plasma

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    The aim of the study was to demonstrate the influence of target gene and amplification product length on the performance of fetal gender determination systems using maternal plasma. A total of 40 pairs of plasma DNA samples from pregnant women and genomic DNA samples from maternal blood, amniotic fluid and paternal blood were isolated for gender determination by amplification of the amelogenin gene and 17 Y-chromosome STR loci, using three different commercial kits. The gender of the fetuses was confirmed by cytogenetic analysis or phenotype at birth. Both the AmpFâ„“STR-Identifiler amplification kit and the Mini-STR Amplification kit for amelogenin gene detection were reliable in determining fetal gender (92.0% and 96.0%, respectively), but false negatives were present in both systems. AmpFâ„“STR-Yfiler was found to be fully reliable as it amplified Y-STR in all cases of pregnancies with male fetuses and thus was 100% correct in determining fetal gender. The results demonstrated that multiple fluorescent PCR for 17 Y-STR loci was more reliable than AMELY gene testing in fetal sex determination with maternal plasma. We also found that the shorter amplification products could improve the performance of fetal gender determination systems

    Epidemiological characteristics and risk factors of severe asthma in children: a single-center prospective cohort study

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    Objective·To explore the epidemiological characteristics of severe asthma in children and analyze the risk factors.Methods·A single-center prospective cohort study was conducted. Six hundred and seventy four children with difficult-to-treat asthma who visited the Children´s Hospital of Fudan University from January 1 to December 31, 2021 were included to establish a dynamic cohort. Basic information (including gender, age, gestational age at birth, birth weight, etc.) and comorbidity of the cohort members were collected. The asthma control status, drug inhalation technique level, medication compliance, pulmonary function parameters [forced expiratory volume in one second (FEV1) as a percent-age of the predicted value (FEV1%pred), FEV1/ forced vital capacity (FVC), and the rate of estimated values of forced expiratory flow at 50% of FVC exhaled (FEF50), FEF75, and FEF25-75 in percent-predicted value, respectively], airway inflammation index [fraction exhaled nitric oxide (FeNO)], and allergy status parameters [eosinophil (EOS) and immunoglobulin E (IgE)] of all cohort members were evaluated. All cohort members underwent re-evaluation respectively at the specialist asthma clinic of the hospital at 3, 6, 9, and 12 months.Results·At the endpoint of the cohort, 52 children were diagnosed with severe asthma, accounting for 7.7%. A high proportion of severe asthma was found in children who were exposed to secondhand smoke, used air conditioning at home all year round, or had coexisting rhinitis/nasosinusitis, FEV1%pred300/μL, IgE>200 IU/L, or FeNO>20/25 ppb [FeNO>20 ppb (≤12 years old) or >25 ppb (>12 years old), 1 ppb=1×10-9 mol/L]. A high proportion of non-severe asthma was found in children who were breastfed for 6 months or longer, or had good medication compliance. The differences were statistically significant (all P<0.05). There were more males in children with severe asthma aged 6‒11 years, and more females in children with severe asthma aged 12‒17 years, with statistical significance (both P<0.05). Multiple-factor Logistic regression analysis showed that only small airway dysfunction was an independent risk factor for severe asthma [OR=5.158 (95%CI 2.516‒10.572)].Conclusion·The proportion of children with severe asthma has a significantly decrease after one year of standardized management in children with difficult-to-treat asthma. Small airway dysfunction is an independent risk factor for the progression to severe asthma

    Success rate of the treatment of early childhood caries under general anesthesia: A retrospective cohort study in different periods

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    InstructionThe purpose of this study was to evaluate the three-year success rate of the treatment for early childhood caries (ECC) under general anesthesia in different periods (2011 and 2018).MethodsChildren (&lt;6 years old) who had severe caries and were treated under general anesthesia in 2011 and 2018 were selected and followed up by telephone appointment and clinical examination. Success rate of each treatment was determined and possible factors associated with treatment failure were evaluated.ResultsThere were 153 patients (with an average age of 48.55 ± 13.37 months) and a total of 2,018 teeth included in the 2011 group. In the 2018 group, there were 273 patients with an average age of 49.01 ± 12.42 months and a total of 3,796 teeth. The success rate in the 2011 group was significantly lower than that in the 2018 group. Teeth with mineral trioxide aggregate (MTA)-capped pulp survived significantly longer than those with calcium hydroxide-capped pulp. The utilization rate of preformed crown restoration was higher than that of resin restoration, and the survival time of dental restorations with preformed crown was prolonged. For posterior teeth, the success rate of indirect pulp capping and pulpotomy was also significantly higher than those without preformed crowns.DiscussionGeneral anesthesia is a safe and effective behavioral management method for uncooperative children's dental treatment. The use of biocompatible pulp capping materials and preformed crowns improved the success rate of treatment and prolonged the survival time of affected teeth

    Validity and Reliability of the Dyslexia Checklist for Chinese Children

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    The study on developmental dyslexia (DD) has fairly matured in the past decades, even when there is a lack of a standardized and convenient instrument for dyslexia in the Chinese population. The purpose of this study was to assess the reliability and validity of the Dyslexia Checklist for Chinese Children (DCCC), which was administered to Chinese students in primary school. A total of 545 students from grades 2 through 6 were recruited in Wuhan to participate in this study. We used confirmatory factor analysis (CFA) to evaluate the structure validity of the DCCC. Concurrent validity was determined via correlations between the DCCC and the verbal comprehension index (VCI), and Chinese achievement. The reliability of the DCCC was assessed via test-retest reliability and internal consistency. The CFA suggested that the first order model with eight factors and 55 items fit the data well (RMSEA = 0.057, CFI = 0.930, and TLI = 0.925). The DCCC was negatively associated with VCI (r = −0.218) and Chinese achievement (r = −0.372). The test-retest reliability of the DCCC was 0.734, and the internal consistency of all subscales was above 0.752. The DCCC thus proved to have adequate validity and reliability to screen Chinese dyslexia among students in grades 2 through 6

    Association of Aortic Stiffness and Cognitive Decline: A Systematic Review and Meta-Analysis

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    Background: Increased aortic stiffness has been found to be associated with cognitive function decline, but the evidence is still under debate. It is of great significance to elucidate the evidence in this debate to help make primary prevention decisions to slow cognitive decline in our routine clinical practice.Methods: Electronic databases of PubMed, EMBASE, and Cochrane Library were systematically searched to identify peer-reviewed articles published in English from January 1, 1986, to March 16, 2020, that reported the association between aortic stiffness and cognitive function. Studies that reported the association between aortic pulse wave velocity (PWV) and cognitive function, cognitive impairment, and dementia were included in the analysis.Results: Thirty-nine studies were included in the qualitative analysis, and 29 studies were included in the quantitative analysis. The aortic PWV was inversely associated with memory and processing speed in the cross-sectional analysis. In the longitudinal analysis, the high category of aortic PWV was 44% increased risk of cognitive impairment (OR 1.44; 95% CI 1.24–1.85) compared with low PWV, and the risk of cognitive impairment increased 3.9% (OR 1.039; 95% CI 1.005–1.073) per 1 m/s increase in aortic PWV. Besides, meta-regression analysis showed that age significantly increased the association between high aortic PWV and cognitive impairment risk.Conclusion: Aortic stiffness measured by aortic PWV was inversely associated with memory and processing speed and could be an independent predictor for cognitive impairment, especially for older individuals

    Eco-development of oil and gas industry: CCUS-EOR technology

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    The current status and development prospects of CCUS-EOR technology development are sorted out from the perspective of ecological development. A good foundation is laid to promote the world low-carbon development pattern and the development of CCUS-EOR technology in oil-rich, low-permeability reservoirs. By analyzing the differences between China and the United States regarding the technology level, application scale, and production effect, the development gaps between different countries in terms of CO2 burial for enhanced oil and gas recovery are derived. In response to these gaps, recommendations for responsive technology research and supporting infrastructure construction are proposed, which are of reference significance for advancing the development of large-scale CCUS technology for all of humanity
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