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The long-distance stable transport of relativistic electron beams (REBs) in plasmas is studied by full three-dimensional particle-in-cell simulations. Theoretical analysis shows that the beam transport is mainly influenced by three transverse instabilities, where the excitation of self-modulation instability, and the suppression of the filamentation instability and the hosing instability are important to realize the beam stable transport. By modulating the transport parameters such as the electron density ratio, the relativistic Lorentz factor, the beam envelopes and the density profiles, the relativistic bunches having a smooth density profile and a length of several plasma wave periods can suppress the beam-plasma instabilities and propagate in plasmas for long distances with small energy losses. The results provide a reference for the research of long-distance and stable transport of REBs, and would be helpful for new particle beam diagnosis technology and space active experiments.
The epidemic of tuberculosis has posed a serious burden in Qinghai province, it is necessary to clarify the epidemiological characteristics and spatial-temporal distribution of TB for future prevention and control measures. We used descriptive epidemiological methods and spatial statistical analysis including spatial correlation and spatial-temporal analysis in this study. Furthermore, we applied an exponential smoothing model for TB epidemiological trend forecasting. Of 43 859 TB cases, the sex ratio was 1.27:1 (M:F), and the average annual TB registered incidence was 70.00/100 000 of 2009–2019. More cases were reported in March and April, and the worst TB stricken regions were the prefectures of Golog and Yushu. High TB registered incidences were seen in males, farmers and herdsmen, Tibetans, or elderly people. 7132 cases were intractable, which were recurrent, drug resistant, or co-infected with other infections. Three likely cases clusters with significant high risk were found by spatial-temporal scan on data of 2009–2019. The exponential smoothing winters' additive model was selected as the best-fitting model to forecast monthly TB cases in the future. This research indicated that TB in Qinghai is still a serious threaten to the local residents' health. Multi-departmental collaboration and funds special for TB treatments and control are still needed, and the exponential smoothing model is promising which could be applied for forecasting of TB epidemic trend in this high-altitude province.
To understand the transmission dynamics of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) in a hospital outbreak to inform infection control actions.
Retrospective cohort study.
General medical and elderly inpatient wards in a hospital in England.
Coronavirus disease 2019 (COVID-19) patients were classified as community or healthcare associated by time from admission to onset or positivity using European Centre for Disease Prevention and Control definitions. COVID-19 symptoms were classified as asymptomatic, nonrespiratory, or respiratory. Infectiousness was calculated from 2 days prior to 14 days after symptom onset or positive test. Cases were defined as healthcare-associated COVID-19 when infection was acquired from the wards under investigation. COVID-19 exposures were calculated based on symptoms and bed proximity to an infectious patient. Risk ratios and adjusted odds ratios (aORs) were calculated from univariable and multivariable logistic regression.
Of 153 patients, 65 were COVID-19 patients and 45 of these were healthcare-associated cases. Exposure to a COVID-19 patient with respiratory symptoms was associated with healthcare-associated infection irrespective of proximity (aOR, 3.81; 95% CI, 1.6.3–8.87). Nonrespiratory exposure was only significant within 2.5 m (aOR, 5.21; 95% CI, 1.15–23.48). A small increase in risk ratio was observed for exposure to a respiratory patient for >1 day compared to 1 day from 2.04 (95% CI, 0.99–4.22) to 2.36 (95% CI, 1.44–3.88).
Respiratory exposure anywhere within a 4-bed bay was a risk, whereas nonrespiratory exposure required bed distance ≤2.5 m. Standard infection control measures required beds to be >2 m apart. Our findings suggest that this may be insufficient to stop SARS-CoV-2 transmission. We recommend improving cohorting and further studies into bed distance and transmission factors.
The butterfly plastic zone theory based on Mohr Coulomb criterion has been widely used in coal mine production. In order to verify the universality of the theory, it is necessary to compare the distribution of plastic zone under different strength criteria. Based on the elastic-plastic mechanics, the principal stress distribution function around the circular tunnel is deduced in the paper, and the boundary and radius of the plastic zone under different strength criteria are calculated. The results show that the change laws of the plastic zone around the circular tunnel under different strength criteria has the following commonness: firstly, with the increase of the lateral pressure coefficient, the shape of the plastic zone presents the change laws of “circle ellipse butterfly”; Secondly, with the increase of the lateral pressure coefficient, the radius of the plastic zone is exponential distribution, while the characteristic value is different when the radius of the plastic zone is infinite. At same time, it shows that the butterfly plastic zone has a low sensitivity dependence on the strength criterion, no matter which strength criterion is adopted, and the butterfly plastic zone will inevitably appear in the surrounding rock mass of circular tunnel in the high deviator stress environment; The plastic zone with butterfly shape is highly sensitive to the stress change, and the small stress change may promote the expansion of the plastic zone. This result is significant for us to understand and prevent rock engineering disasters and accidents.
To improve the endurance performance of long-endurance Unmanned Aerial Vehicles (UAVs), a smart morphing method to adjust the UAV and flight mode continuously during flight is proposed. Using this method as a starting point, a smart morphing long-endurance UAV design is conducted and the resulting improvement in the endurance performance studied. Firstly, the initial overall design of the smart morphing long-endurance UAV is carried out, then the morphing form is designed and various control parameters are selected. Secondly, based on multi-agent theory, an architecture for the smart morphing control system is built and the workflow of the smart morphing control system is planned. The morphing decision method is designed in detail based on the particle swarm optimisation algorithm. Finally, a simulation of the smart morphing approach in the climb and cruise stages is carried out to quantitatively verify the improvement in the endurance performance. The simulation results show that the smart morphing method can improve the cruise time by 4.1% with the same fuel consumption.
Leg weakness (LW) issues are a great concern for pig breeding industry. And it also has a serious impact on animal welfare. To dissect the genetic architecture of limb-and-hoof firmness in commercial pigs, a genome-wide association study was conducted on bone mineral density (BMD) in three sow populations, including Duroc, Landrace and Yorkshire. The BMD data were obtained by ultrasound technology from 812 pigs (including Duroc 115, Landrace 243 and Yorkshire 454). In addition, all pigs were genotyped using genome-by-sequencing and a total of 224 162 single-nucleotide polymorphisms (SNPs) were obtained. After quality control, 218 141 SNPs were used for subsequent genome-wide association analysis. Nine significant associations were identified on chromosomes 3, 5, 6, 7, 9, 10, 12 and 18 that passed Bonferroni correction threshold of 0.05/(total SNP numbers). The most significant locus that associated with BMD (P value = 1.92e−14) was detected at approximately 41.7 Mb on SSC6 (SSC stands for Sus scrofa chromosome). CUL7, PTK7, SRF, VEGFA, RHEB, PRKAR1A and TPO that are located near the lead SNP of significant loci were highlighted as functionally plausible candidate genes for sow limb-and-hoof firmness. Moreover, we also applied a new method to measure the BMD data of pigs by ultrasound technology. The results provide an insight into the genetic architecture of LW and can also help to improve animal welfare in pigs.
Introduction: Despite the visibility of the homeless population, there is limited data on the information of this patient population. Point-in-time counts and survey data from selected samples (such as those admitted to emergency shelter) have primarily been used. This literature suggests that this hard-to-reach population has high rates of presentation at emergency departments (EDs), and as such, EDs often become their main point of contact for health and social services. Leveraging this fact and administrative data we construct a crude census of homeless persons within Ontario. We further examine demographic characteristics of patients experiencing homelessness, and compare this data to findings from previous literature. Methods: All routinely collected administrative health data from EDs located within Ontario, Canada from 2010-2017 were analyzed to examine patient characteristics. Individuals experiencing homelessness were identified by a marker that was adopted in 2009 replacing their recorded postal code with an XX designation. s. Aggregating by LHIN, date and week of year, we examine the overall number of patients experiencing homelessness and number by LHIN location and seasonality. Demographic outcomes examined include age and sex. Results: 640,897 visits to the ED over 7 years were made by 39,525 unique individuals experiencing homelessness. Number of ED visits has steadily increased over 10 years in all of Ontario, despite decline in shelter use for individuals. Presentations were concentrated in large urban centres like Toronto, Ottawa and Hamilton. Fewer presentations occur in the spring and summer months and rise in the winter. Male patients presented older and in greater numbers than female patients. The modal female age of presentation is in the 20-24 age category. The modal male age of presentation is in the 25-29 age category. Older male patients were more likely to have multiple presentations. Conclusion: The utilization of administrative health data offers a novel, cost-effective method to measure demographic characteristics of people experiencing homelessness. Identifying characteristics of homeless patients through this method allows for a more complete understanding of the characteristics of a hard-to-reach population, which will allow policy makers to develop appropriate services for this sub-group. Furthermore, through analysis of trends of demographics over time, changes in the homeless population can be tracked in real-time to allow for coordination and implementation of services in a time-sensitive manner.
Introduction: Administrative data can aid in study and intervention design, incorporating hard-to-reach individuals who may otherwise be poorly represented. We aim to use administrative health data to examine emergency department visits by people experiencing homelessness and explore the application of this data for planning interventions. Methods: We conducted a serial cross-sectional study examining emergency department use by people experiencing homelessness and non-homeless individuals in the Niagara region of Ontario, Canada. The study period included administrative health data from April 1st, 2010 to March 31st, 2018. Outcomes included number of visits, number of unique patients; group proportions of Canadian Triage and Acuity Scale (CTAS) scores; time spent in emergency; and time to see an MD. Descriptive statistics were generated, and t-tests were performed for point estimates and a Mann-Whitney U test for distributional measures. Results: Our data included 1,486,699 emergency department visits. The number of unique people experiencing homelessness ranged from 91 in 2010 to 344 in 2017, trending higher over the study period compared to non-homeless patients. The rate of visits increased from 1.7 to 2.8 per person. People experiencing homelessness tend to present later in the day and with higher overall acuity as compared to the general population. Time in emergency department and time to see an MD were greater among people experiencing homelessness. Conclusion: Administrative health data allows researchers to enhance interventions and models of care to improve services for vulnerable populations. Given the challenging fiscal realities of research, our study provides insights to more effectively target interventions for vulnerable populations.
Introduction: People experiencing homelessness have complex psychiatric and medical presentations, and have poor access to primary care. Thus, emergency departments (EDs) often become their main point of healthcare contact. Using routinely collected administrative data from EDs, we examine the ED utilization, health and reasons for presentations of people experiencing homelessness.. Methods: All routinely collected administrative health data from EDs located within Ontario, Canada from 2010-2017 were analyzed. Individuals experiencing homelessness were identified by a marker that was adopted in 2009 replacing their recorded postal code with an XX designation. Outcomes include number of unique patients, number of visits and repeat visits, CTAS scores, ambulance utilization, and type of ICD-10 presentation. Results: 640,897 visits to the ED over 10 years were made by 39,525 unique individuals experiencing homelessness. A visit to an ED by a homeless patient resulted in repeat presentation on the same day 5% of the time. The median repeat presentation to an ED was 14 days. In people experiencing homelessness, the most prevalent category of presentations were primary mental health diagnoses, accounting for 34.8% of visits (n = 223,392). Under mental health conditions, psychoactive substance use presentations made up more than 54% of the presentations (n = 121,112). Alcohol was by far the most common cause of substance use/induced disorders (n = 84,805). Conclusion: Applications of administrative data presents a novel method of measuring health and healthcare outcomes for marginalized populations. We found people experiencing homelessness are presenting to ED more frequently in Ontario, with significant mental health and addiction problems. Our study identifies several important health vulnerabilities within the population, which may serve as potential targets for future interventions.
Introduction: Understanding how homeless patients interact with healthcare systems can be challenging. The nature of the population is such that identifying and following these persons can be severely limited by data. Previous studies have used survey data which relies on self-reporting and selected samples such as those persons admitted to homeless shelters (Gray et al. 2011). Other studies have been able to leverage administrative data but only for selected local geographic areas (Somers et al. 2016, Tompkins et al 2003). It is possible that the current literature has not examined a large proportion of homeless persons and their healthcare use. This is concerning because this population can have higher associated medical costs and greater medical resource utilization especially with regards to psychiatric and emergency department (ED) resources (Tulloch et al. 2012, Forchuk et al, 2015). Methods: Administrative health data (2010 to 2017) is used to analyze ambulatory care records for homeless individuals in Ontario, Canada. Uniquely, we are able to use ED contacts as a way of identifying homeless migrations from region to region within Ontario. Using a network analysis we identify high impact ED nodes and discrete hospital networks where homeless patients congregate. We are also able to more fully characterize this population's demographics, health issues, and disposition from the ED. Results: We provide a more complete understanding of migration patterns for homeless individuals, across Ontario and their concomitant ED use and hospitalizations. The three most frequented regions in Ontario (n = 640,897) were Toronto Central (35.96%), Hamilton Niagara Halimand Brant (8.9%) and Champlain (7.84%). In subsequent visits, the majority of patients presented to different EDs, however a subgroup who always presented to the same site was present. Over the 7 year period, migration between visits occurred most often between urban areas, and increased as a whole. Conclusion: The results of the study allow for the enhancement care coordination for vulnerable populations and enhance the availability and delivery of services for sub-groups of homelessness whose care needs may differ based on migration patterns. Services can be coordinated between jurisdictions for homeless individuals, and appropriate referrals can be made across the health care system. Further evidence is provided for a novel method of mapping migration among the homeless and its associations and effects on ED use.
This report is on the synthesis by electrospinning of multiferroic core-shell nanofibers of strontium hexaferrite and lead zirconate titanate or barium titanate and studies on magneto-electric (ME) coupling. Fibers with well-defined core–shell structures showed the order parameters in agreement with values for nanostructures. The strength of ME coupling measured by the magnetic field-induced polarization showed the fractional change in the remnant polarization as high as 21%. The ME voltage coefficient in H-assembled films showed the strong ME response for the zero magnetic bias field. Follow-up studies and potential avenues for enhancing the strength of ME coupling in the core–shell nanofibers are discussed.
Sensory system information is thought to play an important role in drug addiction related responses. However, how somatic sensory information participates in the drug related behaviors is still unclear. Many studies demonstrated that drug addiction represents a pathological usurpation of neural mechanisms of learning and memory that normally relate to the pursuit of rewards. Thus, elucidate the role of somatic sensory in drug related learning and memory is of particular importance to understand the neurobiological mechanisms of drug addiction.
In the present study, we investigated the role of somatosensory system in reward-related associative learning using the conditioned place preference model. Lesions were made in somatosensory cortices either before or after conditioning training. We found that lesion of somatosensory cortices before, rather than after morphine conditioning impaired the acquisition of place preference.
These results demonstrate that somatosensory cortices are necessary for the acquisition but not retention of morphine induced place preference.
White matter abnormalities have been repeatedly reported in both schizophrenia and bipolar disorder (BD) diseases from diffusion tensor imaging (DTI) studies respectively, while the empirical evidences about the diagnostic specificity of white matter abnormalities in these disorders are still limited.
25 patients with paranoid schizophrenia and 18 patients with bipolar mania were recruited from the in-patient unit of the Mental Health Centre, West China Hospital, China.
Patients were diagnosed according to the criteria of Diagnostic and Statistical Manual of Mental Disorders-Version IV (DSM- IV). 30 healthy controls were recruited from the community by means of leaflets distributed throughout Chengdu city.
This study sought to investigate the alterations in fractional anisotropy (FA) in white matter throughout the entire brain of patients from Chengdu, China with paranoid schizophrenia and bipolar mania.
Diffusion tensor imaging (DTI) was used to assess white matter integrity in patients with paranoid schizophrenia and bipolar mania, as well as in normal controls. The differences in FA were measured by use of voxel-based analysis.
Reduced FA was found in the left posterior corona radiate (PCR) in patients with bipolar mania and paranoid schizophrenia compared to the controls. Patients with bipolar mania also showed a significant reduction in FA in right posterior corona radiate and in right anterior thalamic radiation (ATR).
Common abnormalities in the left PCR might imply an overlap in white matter pathology of both diseases and might be related to the shared risk factors for both disorders.
The relative effect of the atypical antipsychotic drugs and conventional agents on neurocognition in patients with early-stage schizophrenia has not been comprehensively determined.
The present study aimed to assess the cognitive effects of atypical and conventional antipsychotic drugs on neurocognition under naturalistic treatment conditions.
In a 12 months open-label, multicenter study, 698 patients with early-stage schizophrenia (< 5 years) were monotherapy with chlorpromazine, sulpiride, clozapine, risperidone, olanzapine, quetiapine or aripiprazole. Wechsler Memory Scale--Revised Visual Reproduction Test, Wechsler Adult Intelligence Scale Revised Digit Symbol Test and Digit-span Task Test, Trail Making Tests Part A and Part B, and Wisconsin Card Sorting Test were administered at baseline and 12 months follow-up evaluation. The primary outcome was change in a cognitive composite score after 12 months of treatment.
Compared with scores at baseline, the composite cognitive test scores and individual test scores had significant improvement for all seven treatment groups at 12-month follow-up evaluation (all p-values ≤ 0.013). However, olanzapine and quetiapine provided greater improvement than that provided by chlorpromazine and sulpiride in the composite score, processing speed and executive function (all p-values ≤ 0.045).
Both conventional and atypical antipsychotic medication long-term maintenance treatment can benefit congitive function in patients with early-stage schizophrenia, but olanzapine and quetiapine may be superior to chlorpromazine and sulpiride in improving some areas of neurocognitive function.
Depression and anxiety disorders are prevalent mental disorders in China. But some those patients do not seek help from psychiatrists firstly but see internists first.
Objectives and aims
This study aimed to investigate the prevalence of depressive - anxiety disorders in gastroenterology outpatients and assess the detection rate provided by physicians in China.
A multicenter, hospital-based cross-sectional study was carried on in the 15 large general hospitals of five cities cross China. A total of 1995 gastroenterological outpatients were screened by Hospital Anxiety and Depression Scale (HADS). Subjects whose HADS scores ≥ 8 were interviewed by psychiatrists, using Mini International Neuropsychiatric Interview (M.I.N.I) to make further diagnoses. Physicians’ diagnoses and treatment were recorded.
The adjusted prevalence of depressive disorder and anxiety disorders was 14.39% and 9.42% respectively.
The prevalence of depressive-anxiety disorder is high in gastroenterology outpatients in China, which suggests the related training of detecting these mental disorders is needed to gastroenterologists.
Tuberculosis (TB) is generally considered a disease that principally afflicts the low-income segments of a population. In the Nanshan District of Shenzhen, China, with the economic transformation and a new Headquarters Economy (HE) emerging, there are now more cases in office workers than in manufacturing workers. To illustrate this trend, we describe a small TB outbreak in an office building located in the centre of the rapidly growing HE district. Two active pulmonary tuberculosis cases were found in workers who shared an office, and whole genome sequencing showed that the genetic distance between the strains of the two cases was just one single nucleotide polymorphism, consistent with intra-office transmission. Investigation of 30 other workers in the same or adjacent offices with interviews, interferon-gamma release assays (IGRAs) and chest X-rays, identified one new TB case and latent tuberculosis infection (LTBI) in 40.0% (12/30) of the contacts. The offices were under-ventilated. None of the IGRA positive, asymptomatic contacts agreed to receive treatment for LTBI, presumably due to TB stigma, and over the next 2 years 69.0% (20/29) of the contacts were lost to follow-up. Treatment for LTBI and stigma of TB remain challenges here. Office workers in the HE of rapidly economic developing areas should be targeted with increased vigilance by TB control programmes.
The Square Kilometre Array (SKA) is a planned large radio interferometer designed to operate over a wide range of frequencies, and with an order of magnitude greater sensitivity and survey speed than any current radio telescope. The SKA will address many important topics in astronomy, ranging from planet formation to distant galaxies. However, in this work, we consider the perspective of the SKA as a facility for studying physics. We review four areas in which the SKA is expected to make major contributions to our understanding of fundamental physics: cosmic dawn and reionisation; gravity and gravitational radiation; cosmology and dark energy; and dark matter and astroparticle physics. These discussions demonstrate that the SKA will be a spectacular physics machine, which will provide many new breakthroughs and novel insights on matter, energy, and spacetime.
Coronavirus disease 2019 (COVID-19) pandemic is a major public health concern all over the world. Little is known about the impact of COVID-19 pandemic on mental health in the general population. This study aimed to assess the mental health problems and associated factors among a large sample of college students during the COVID-19 outbreak in China.
This cross-sectional and nation-wide survey of college students was conducted in China from 3 to 10 February 2020. A self-administered questionnaire was used to assess psychosocial factors, COVID-19 epidemic related factors and mental health problems. Acute stress, depressive and anxiety symptoms were measured by the Chinese versions of the impact of event scale-6, Patient Health Questionnaire-9 and Generalized Anxiety Disorder-7, respectively. Univariate and hierarchical logistic regression analyses were performed to examine factors associated with mental health problems.
Among 821 218 students who participated in the survey, 746 217 (90.9%) were included for the analysis. In total, 414 604 (55.6%) of the students were female. About 45% of the participants had mental health problems. The prevalence rates of probable acute stress, depressive and anxiety symptoms were 34.9%, 21.1% and 11.0%, respectively. COVID-19 epidemic factors that were associated with increased risk of mental health problems were having relatives or friends being infected (adjusted odds ratio = 1.72–2.33). Students with exposure to media coverage of the COVID-19 ≥3 h/day were 2.13 times more likely than students with media exposure <1 h/day to have acute stress symptoms. Individuals with low perceived social support were 4.84–5.98 times more likely than individuals with high perceived social support to have anxiety and depressive symptoms. In addition, senior year and prior mental health problems were also significantly associated with anxiety or/and depressive symptoms.
In this large-scale survey of college students in China, acute stress, anxiety and depressive symptoms are prevalent during the COVID-19 pandemic. Multiple epidemic and psychosocial factors, such as family members being infected, massive media exposure, low social support, senior year and prior mental health problems were associated with increased risk of mental health problems. Psychosocial support and mental health services should be provided to those students at risk.
To solve the on-ground lateral direction control problem of the unswept flying-wing unmanned aerial vehicle (UAV) without rudder, steering system or breaking system, a control approach which uses differential propeller thrust to control the lateral direction is proposed. First, a mathematical model of the unswept flying-wing UAV on-ground moving is established. Second, based on the active disturbance rejection control (ADRC) theory, a yaw angle controller is designed by using the differential propeller thrust as the control output. Finally, a straight line trajectory tracking control law is designed by improving the vector field path following method. Experiment results show that the proposed control laws have a shorter response time, better robustness and better control precision compared with proportional integral derivative (PID) controller. The proposed controller has small computational complexity, simple parameter setting process, and uses practical measurable physical quantities, providing a reference solution for further engineering applications.