558 research outputs found
Dephasing effect promotes the appearance of quantized Hall plateaus
The quantum Hall effect (QHE) is a topologically protected phenomenon which
has been observed in various systems. In experiments, the size of Hall bar
device to realize the QHE is generally much larger than the phase coherence
length, in which the quantum coherence of electrons is destroyed. Here, we
theoretically study the influence of dephasing effect on the quantized Hall
(QH) plateaus. We find that the QH plateau disappears in perfectly quantum
coherent systems if the coupling between leads and central region is imperfect.
The Hall resistance is very large and strongly oscillates instead of presenting
the QH plateau in this case. However, by introducing the dephasing, the Hall
resistance decreases and the QH plateau appears gradually. Similar results can
also be observed for the quantum anomalous Hall effect. Our results propose
that dephasing effect promotes the appearance of QH plateaus, which opens a new
topic of the dephasing effect on topological systems.Comment: 23 pages, 11 figure
Relationship between neonatal dacryocystitis and cesarean section and the treatment of neonatal dacryocystitis
AIM: To explore the treatment of neonatal dacryocystitis of different ages and the relationship between caesarean section and neonatal dacryocystitis.<p>METHODS: A total of 260 cases(260 eyes)of children with neonatal dacryocystitis were divided into 1-3 months group, 4-6 months group, 7-12 months group and 13-24 months group, Each group was respectively given the lacrimal sac massage, lacrimal passage irrigation and probing of lacrimal passage method. Curative effect of each method was observed in different groups. Analysis was made to determine whether caesarean section was the cause of neonatal dacryocystitis.<p>RESULTS: The comparison between 1-3 months group and 4-6 months group showed significant difference(<i>χ</i><sup>2</sup>=19.89, <i>P</i><0.05). Lacrimal sac massage was effective for babies under 6 months, particularly in 1-3 months babies. The curative effect of lacrimal passage irrigation in four groups was compared, and there was statistical significance in the difference between the curative effect of each group(<i>χ</i><sup>2</sup>=54.95, <i>P</i><0.05). The difference between the 1-3 months group and 4-6 months group was <i>χ</i><sup>2</sup>=0.00003, <i>P</i>>0.05, lacrimal passage irrigation of these two groups showed no significant difference in efficacy. The comparison result between the other two groups showed no significant difference(<i>P</i><0.05), lacrimal passage irrigation effects are different from each group. The comparison result between 7-12 months group and 13-24 months group was <i>χ</i><sup>2</sup>=10.29, <i>P</i><0.05. Infants born by cesarean section accounted for 85% of all cases. <p>CONCLUSION:Lacrimal sac massage can exert very good therapeutic effects in infants less than 3 months. The curative effects of irrigation of lacrimal passage are quite good in babies under 12 months. Probing of lacrimal passage has a good curative effect in 7-12 months infants, but a poor curative effect in babies over 12 months. Caesarean section is an important cause for neonatal dacryocystitis
Meta-analysis of antiviral protection of white spot syndrome virus vaccine to the shrimp
Currently, white spot syndrome virus (WSSV) is one of the most serious pathogens that impacts shrimp farming around the world. A WSSV vaccine provides a significant protective benefit to the host shrimp. Although various types of vaccines against WSSV have emerged, the immune effects among them were not compared, and it remains unclear which type of vaccine has the strongest protective effect. Meanwhile, due to the lack of effective routes of administration and immunization programs, WSSV vaccines have been greatly limited in the actual shrimp farming. To answer these questions, this study conducted a comprehensive meta-analysis over dozens of studies and compared all types WSSV vaccines, which include sub-unit protein vaccines, whole virus inactivated vaccines, DNA vaccines and RNA-based vaccines. The results showed that the RNA-based vaccine had the highest protection rate over the other three types of vaccines. Among the various sub-unit protein vaccines, VP26 vaccine had the best protective effects than other sub-unit protein vaccines. Moreover, this study demonstrated that vaccines expressed in eukaryotic hosts had higher protection rates than that of prokaryotic systems. Among the three immunization modes (oral administration, immersion and injection) used in monovalent protein vaccines, oral administration had the highest protection rate. In natural conditions, shrimp are mostly infected by the virus orally. These results provide a guide for exploration of a novel WSSV vaccine and help facilitate the application of WSSV vaccines in shrimp farming
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Forecasting incidence of infectious diarrhea using random forest in Jiangsu Province, China
Background
Infectious diarrhea can lead to a considerable global disease burden. Thus, the accurate prediction of an infectious diarrhea epidemic is crucial for public health authorities. This study was aimed at developing an optimal random forest (RF) model, considering meteorological factors used to predict an incidence of infectious diarrhea in Jiangsu Province, China.
Methods
An RF model was developed and compared with classical autoregressive integrated moving average (ARIMA)/X models. Morbidity and meteorological data from 2012 to 2016 were used to construct the models and the data from 2017 were used for testing.
Results
The RF model considered atmospheric pressure, precipitation, relative humidity, and their lagged terms, as well as 1–4 week lag morbidity and time variable as the predictors. Meanwhile, a univariate model ARIMA (1,0,1)(1,0,0)52 (AIC = − 575.92, BIC = − 558.14) and a multivariable model ARIMAX (1,0,1)(1,0,0)52 with 0–1 week lag precipitation (AIC = − 578.58, BIC = − 578.13) were developed as benchmarks. The RF model outperformed the ARIMA/X models with a mean absolute percentage error (MAPE) of approximately 20%. The performance of the ARIMAX model was comparable to that of the ARIMA model with a MAPE reaching approximately 30%.
Conclusions
The RF model fitted the dynamic nature of an infectious diarrhea epidemic well and delivered an ideal prediction accuracy. It comprehensively combined the synchronous and lagged effects of meteorological factors; it also integrated the autocorrelation and seasonality of the morbidity. The RF model can be used to predict the epidemic level and has a high potential for practical implementation
The role of quality of care and attitude towards disability in the relationship between severity of disability and quality of life: findings from a cross-sectional survey among people with physical disability in China
Background: People with physical disability (PWPD) is the largest subgroup of people with disability (PWD) in China, but few studies have been conducted among this vulnerable population. The objective of this study was to investigate the level of quality of life (QoL), self-perceived quality of care and support (QOCS), severity of disability and personal attitude towards disability among people with physical disability in China, as well as to identify how QoL can be affected by severity of disability through QOCS and personal attitude towards disability among PWPD. Methods: A cross-sectional study was conducted among 1,853 PWPD in Guangzhou, China. Data were collected on participants’ QoL, QOCS, personal attitude towards disability and severity of disability. Structural equation modeling was used to examine the effects of the other variables on QoL. Results: Even with a mild disability (mean score:1.72), relatively low levels of QoL (mean score: 2.65- 3.22) and QOCS (mean score: 2.95 to 3.28), as well as unfavorable personal attitude towards disability (mean score: 2.75 to 3.36) were identified among PWPD. According to SEM, we found that the influence of severity of physical disability on QoL is not only exerted directly, but is also indirectly through QOCS and their personal attitudes towards disability, with QOCS playing a more important mediating role than PWPD’s attitudes towards their own disability. Conclusions: Unfavorable health status was identified among PWPD in China. Focusing on improvement of assistance and care services has the potential to substantially improve PWPD’s QoL. Further research should focus on understanding the needs and their current state of health care of PWPD in China thus being able to develop better interventions for them
The dependent correlation between soil multifunctionality and bacterial community across different farmland soils
IntroductionMicroorganisms play a critical role in soil biogeochemical cycles, but it is still debated whether they influence soil biogeochemical processes through community composition and diversity or not. This study aims to investigate variation in bacterial community structure across different soils and its correlation to soil multifunctionality. Soil samples were collected from five typical farmland zones along distinct climatic gradients in China.MethodsThe high-throughput sequencing (Illumina MiSeq) of 16S rRNA genes was employed to analyze bacterial community composition in each soil sample. Multivariate analysis was used to determine the difference in soil properties, microbial community and functioning, and their interactions.ResultsCluster and discrimination analysis indicated that bacterial community composition was similar in five tested soil samples, but bacterial richness combined with soil enzyme activities and potential nitrification rate (PNR) contributed most to the differentiations of soil samples. Mantel test analysis revealed that bacterial community composition and richness were more significantly shaped by soil nutrient conditions and edaphic variables than bacterial diversity. As for soil multifunctionality, soil microbial community level physiological profiles were little affected by abiotic and biotic factors, while soil enzymes and PNR were also significantly related to bacterial community composition and richness, in addition to soil N and P availability.ConclusionCumulatively, soil enzymes’ activities and PNR were greatly dependent on bacterial community composition and richness not diversity, which in turn were greatly modified by soil N and P availability. Therefore, in the future it should be considered for the role of fertilization in the modification of bacterial community and the consequent control of nutrient cycling in soil
An Updated Search of Steady TeV Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array
Using the data taken from Tibet II High Density (HD) Array (1997
February-1999 September) and Tibet-III array (1999 November-2005 November), our
previous northern sky survey for TeV ray point sources has now been
updated by a factor of 2.8 improved statistics. From to
in declination (Dec) range, no new TeV ray point
sources with sufficiently high significance were identified while the
well-known Crab Nebula and Mrk421 remain to be the brightest TeV ray
sources within the field of view of the Tibet air shower array. Based on the
currently available data and at the 90% confidence level (C.L.), the flux upper
limits for different power law index assumption are re-derived, which are
approximately improved by 1.7 times as compared with our previous reported
limits.Comment: This paper has been accepted by hepn
Prevalence of human papillomavirus and cervical intraepithelial neoplasia in China: A pooled analysis of 17 population-based studies
High-risk (HR) human papillomavirus (HPV) prevalence has been shown to correlate well with cervical cancer incidence rates. Our study aimed to estimate the prevalence of HR-HPV and cervical intraepithelial neoplasia (CIN) in China and indirectly inform on the cervical cancer burden in the country. 30,207 women from 17 population-based studies throughout China were included. All women received HPV DNA testing (HC2, Qiagen), visual inspection with acetic acid, and liquid-based cytology. Women positive for any test received colposcopy-directed or 4-quadrant biopsies. 29,579 women had HR-HPV testing results, of whom 28,761 had biopsy-confirmed (9019, 31.4%) or assumed (19,742, 68.6%) final diagnosis. Overall crude HR-HPV prevalence was 17.7%. HR-HPV prevalence was similar in rural and urban areas but showed dips in different age groups: at age 25–29 years (11.3%) in rural and at age 35–39 (11.3%) in urban women. In rural and urban women, age-standardized CIN2 prevalence was 1.5% (95%CI: 1.4%–1.6%) and 0.7% (95%CI: 0.7%–0.8%), and CIN3+ prevalence was 1.2% (95%CI: 1.2%–1.3%) and 0.6% (95%CI: 0.5%–0.7%), respectively. Prevalence of CIN3+ as a percentage of either all women or HR-HPV positive women steadily increased with age, peaking in 45–49 year-old women. High prevalence of HR-HPV and CIN3+ was detected in both rural and urban China. The steady rise of CIN3+ up to the age group 45–49 is attributable to lack of lesion removal through screening. Our findings document the inadequacy of current screening in China while indirectly raising the possibility that the cervical cancer burden in China is under-reported
Elevated Plasma Levels of Drebrin in Glaucoma Patients With Neurodegeneration
Glaucoma is an optic neuropathy characterized by progressive degeneration of retinal ganglion cells (RGCs). Aberrations in several cytoskeletal proteins, such as tau have been implicated in the pathogenesis of neurodegenerative diseases, could be initiating factors in glaucoma progression and occurring prior to axon degeneration. Developmentally regulated brain protein (Drebrin or DBN1) is an evolutionarily conserved actin-binding protein playing a prominent role in neurons and is implicated in neurodegenerative diseases. However, the relationship between circulating DBN1 levels and RGC degeneration in glaucoma patients remains unclear. In our preliminary study, we detected drebrin protein in the plasma of glaucoma patients using proteomic analysis. Subsequently, we recruited a total of 232 patients including primary angle-closure glaucoma (PACG), primary open-angle glaucoma (POAG) and Posner-Schlossman syndrome (PS) and measured its DBN1 plasma levels. We observed elevated DBN1 plasma levels in patients with primary glaucoma but not in patients with PS compared to nonaxonopathic controls. Interestingly, in contrast to tau plasma levels increased in all groups of patients, elevated drebrin plasma levels correlated with retinal nerve fiber layer defect (RNFLD) in glaucoma patients. To further explore the expression of DBN1 in neurodegeneration, we conducted experiment of optic nerve crush (ONC) models, and observed increased expression of DBN1 in the serum as well as in the retina and then decreased after ONC. This result reinforces the potentiality of circulating DBN1 levels are increased in glaucoma patients with neurodegeneration. Taken together, our findings suggest that circulating DBN1 levels correlated with RNFLD and may reflect the severity of RGCs injury in glaucoma patients. Combining measurement of circulating drebrin and tau levels may be a useful indicator for monitoring progression of neurodegenerative diseases
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