144 research outputs found
Relation of a New Interpretation of Stochastic Differential Equations to Ito Process
Stochastic differential equations (SDE) are widely used in modeling
stochastic dynamics in literature. However, SDE alone is not enough to
determine a unique process. A specified interpretation for stochastic
integration is needed. Different interpretations specify different dynamics.
Recently, a new interpretation of SDE is put forward by one of us. This
interpretation has a built-in Boltzmann-Gibbs distribution and shows the
existence of potential function for general processes, which reveals both local
and global dynamics. Despite its powerful property, its relation with classical
ones in arbitrary dimension remains obscure. In this paper, we will clarify
such connection and derive the concise relation between the new interpretation
and Ito process. We point out that the derived relation is experimentally
testable.Comment: 16 pages, 2 figure
Outbreak of COVID-19 and SARS in mainland China: a comparative study based on national surveillance data
Objective To compare the epidemiological characteristics
and transmission dynamics in relation to interventions
against the COVID-19 and severe acute respiratory
syndrome (SARS) outbreak in mainland China.
Design Comparative study based on a unique data set of
COVID-19 and SARS.
Setting Outbreak in mainland China.
Participants The final database included 82 858
confirmed cases of COVID-19 and 5327 cases of SARS.
Methods We brought together all existing data sources
and integrated them into a comprehensive data set.
Individual information on age, sex, occupation, residence
location, date of illness onset, date of diagnosis and
clinical outcome was extracted. Control measures
deployed in mainland China were collected. We
compared the epidemiological and spatial characteristics
of COVID-19 and SARS. We estimated the effective
reproduction number to explore differences in transmission
dynamics and intervention effects.
Results Compared with SARS, COVID-19 affected more
extensive areas (1668 vs 230 counties) within a shorter
time (101 vs 193 days) and had higher attack rate (61.8 vs
4.0 per million persons). The COVID-19 outbreak had only
one epidemic peak and one epicentre (Hubei Province),
while the SARS outbreak resulted in two peaks and two
epicentres (Guangdong Province and Beijing). SARSCoV-2 was more likely to infect older people (median
age of 52 years), while SARS-CoV tended to infect young
adults (median age of 34 years). The case fatality rate
(CFR) of either disease increased with age, but the CFR of
COVID-19 was significantly lower than that of SARS (5.6%
vs 6.4%). The trajectory of effective reproduction number
dynamically changed in relation to interventions, which
fell below 1 within 2 months for COVID-19 and within 5.5
months for SARS.
Conclusions China has taken more prompt and effective
responses to combat COVID-19 by learning lessons from
SARS, providing us with some epidemiological clues to
control the ongoing COVID-19 pandemic worldwid
Body-centered-cubic Ni and its magnetic properties
The body-centered-cubic (bec) phase of Ni, which does not exist in nature, has been achieved as a thin film on GaAs(001) at 170 K via molecular beam epitaxy. The bec Ni is ferromagnetic with a Curie temperature of 456 K and possesses a magnetic moment of 0.52 \uc2\ub1 0.08 \uce\ubcB/atom. The cubic magneto-crystalline anisotropy of bec Ni is determined to be +4.0 \uc3\u97 105 ergs \uc2\ub7 cm-3, as opposed to -5.7 \uc3\u97 10 4 ergs \uc2\ub7 cm-3 for the naturally occurring face-centered-cubic (fcc) Ni. This sharp contrast in the magnetic anisotropy is attributed to the different electronic band structures between bec Ni and fcc Ni, which are determined using angle-resolved photoemission with synchrotron radiation
Recognition of the Phanerozoic “Young Granite Gneiss” in the central Yeongnam Massif
Up to now, all the high-grade gneisses of the Korean peninsula have been regarded as Precambrian basement rocks and presence of the Phanerozoic high-grade metamorphic rocks have remained unknown. However, such granite gneiss is discovered through this study from the central Yeongnam massif near Gimcheon. SHRIMP zircon U-Pb age determinations on the granite gneiss, having well-developed gneissic foliations and migmatitic textures, reveal concordant age of ca. 250 Ma indicating the Early Triassic emplacement of this pluton, which is in contradict to the previous belief that it is a Precambrian product. Even though the granite gneiss reveals well-developed gneissic foliations and some zircons show rather low Th/U ratios, the metamorphic age has not been determined successfully. However, the age of metamorphism can be constrained as middle Triassic considering the absence of any evidences of metamorphism from the nearby granitic plutons having emplacement ages of ca. 225 Ma. Early Triassic emplacement and subsequent Middle Triassic metamorphism of the granite gneiss from the Yeongnam massif bear a remarkable resemblance to the case of South China block. We suggest the possibility that Early to Middle Triassic metamorphism of the Korean peninsula might be products of the intracontinental collisional events not directly related with the Early Triassic continental collision event
Strategies for Controlled Placement of Nanoscale Building Blocks
The capability of placing individual nanoscale building blocks on exact substrate locations in a controlled manner is one of the key requirements to realize future electronic, optical, and magnetic devices and sensors that are composed of such blocks. This article reviews some important advances in the strategies for controlled placement of nanoscale building blocks. In particular, we will overview template assisted placement that utilizes physical, molecular, or electrostatic templates, DNA-programmed assembly, placement using dielectrophoresis, approaches for non-close-packed assembly of spherical particles, and recent development of focused placement schemes including electrostatic funneling, focused placement via molecular gradient patterns, electrodynamic focusing of charged aerosols, and others
Prunella vulgaris: A comprehensive review of chemical constituents, pharmacological effects and clinical applications.
Prunella vulgaris (PV) is a perennial herb belonging to the Labiate family and is widely distributed in northeastern Asian countries such as Korea, Japan, and China. It is reported to display diverse biological activities including anti-microbial, anti-cancer, and anti-inflammation as determined by in vitro or in vivo studies. So far, about 200 compounds have been isolated from PV plant and majority of these have been characterized mainly as triterpenoids, sterols and flavonoids, followed by coumarins, phenylpropanoids, polysaccharides and volatile oils. This review summarizes and analyzes the current knowledge on the chemical constituents, pharmacological activities, mechanisms of action and clinical applications of the PV plant including its potential as a future medicinal plant. Although some of the chemical constituents of the PV plant and their mechanism of action have been investigated the biological activities of many of these remain unknown and further clinical trials are required to further enhance its reputation as a medicinal plant
Micromorphology of Latosols in Hainan and environmental significance differences between vemiculated red soils in south China and Latosols
Tropical soils with unique pedogenic processes influenced by warm humid climate are investigated worldwidely. 1atosols are zonal soils in tropical areas of China and have been the subject for scientists studying mineralogical and geochemical characteristics. However studies on micromorphological characteristics of the soil are still far and rare. In this study, micromorphological features and pedogenic processes of three Latosol profiles derioedfrom different parent materials from Hainan Island are studied with soil micromorphological, clay mineralogical and chemical methods. Vermiculated red soils in South China, which were formed in the mid-Pleistocene, are called Latosols in some studies. To provide evidence for the study of palaeoenvironment and archaeology, vermiculated red soils are compared with Latosols in this study. The results indicate that Latosols mainly have two typical micromorphological features. One is the absence of unweatherable minerals and illuvial clay, and the other is the presence of nodules of iron and manganese oxides resulting from weathering and isotropic b-fabric in good drainage conditions. The typical pedogenic processes of latosols are strong weathering, rubification, homogenization, eluviation and remarkable desilication. In poor drainage conditions, some pseudogley features are formed. Resulting from strong chemical weathering under the tropical climate, Latosols are strongly developed. Compared with Latosols, vermiculated red soils are less developed. They cannot be classified as latosols and Oxisols, but tend to be classified as Ultisols in the American Soil Taxonomy, corresponding to red earths in the Chinese Soil Genetic Classification. This indicates wet, warm climate and indeciduous, latifoliate vegetation in the vast areas south of the Yangtze River during the forming period of vermiculated red soils
Effects of Dietary Wheat Gluten Meal on Growth, Intestinal Morphology, and Microbiome in Juvenile Large Yellow croaker Larimichthys crocea
Wheat gluten meal (WGM) was evaluated as a replacement for fish meal (FM) for juvenile Larimichthys crocea.FM was replaced by 0%, 25%, 50%, 75%, and 100% of WGM (WGM0, WGM25, WGM50, WGM75, and WGM100, respectively). In addition, all diets except the control group were supplemented with amino acids. Fish were fed twice daily for 56 days. There were no significant differences in survival and feed conversion ratio (FCR) among all treatments (P>0.05). WGM25, WGM50, and WGM75 groups had significantly higher specific growth rate (SGR) and weight gain ratio (WGR) than those fed with WGM0 (P0.05). The indexes of Chao1, Shannon, Simpson, and Good coverage in fish fed with WGM0, WGM50, and WGM100 were not significantly affected (P>0.05). Firmicutes (81.03~94.03%) were the dominant bacterial community in juvenile large yellow croaker. Compared with the WGM0 group, the abundance of Firmicutes increased significantly, and Proteobacteria decreased significantly in the WGM100 group (P<0.05). These results suggested that WGM could replace 366.3 g kg-1 FM of the juvenile large yellow croaker diet
Synthesis, self-assembly, disassembly, and reassembly of two types of Cu2O nanocrystals unifaceted with {001} or {110} planes
10.1021/ja100151fJournal of the American Chemical Society132176131-6144JACS
Therapeutic effects of Sophora moorcroftiana alkaloids in combination with albendazole in mice experimentally infected with protoscolices of Echinococcus granulosus
The objective of the present study was to determine if the combination of alkaloids from Sophora moorcroftiana seeds and albendazole might be effective in the treatment of experimental echinococcosisin female NIH mice (6 weeks old and weighing 18-20 g, N = 8 in each group) infected withprotoscolices of Echinococcus granulosus. Viable protoscolices (N = 6 x 103) were cultured in vitro in 1640 medium and mortality was calculated daily. To determine the in vivo efficacy, mice were inoculated intraperitoneally with viable protoscolices and then treated once daily by gavage for three months with the alkaloids (50 mg kg-1 day-1) and albendazole (50 mg kg-1 day-1), separately and in combination (both alkaloids at 25 mg kg-1 day-1 and albendazole at 25 mg kg-1 day-1). Next, the hydatid cysts collected from the peritoneal cavity of the animals were weighed and serum IL-4, IL-2, and IgE levels were analyzed. Administration of alkaloids to cultured protoscolices showed significant dose- and time-dependent killing effects. The weight of hydatid cysts was significantly decreased upon treatment with each drug (P < 0.01), but the decrease was more prominent and the rate of hydatid cyst growth inhibition was much higher (76.1%) in the group receiving the combined treatments (18.3 ± 4.6 mg). IL-4 and total IgE were decreased (939 ± 447 pg/mL and 2.03 ± 0.42 IU/mL, respectively) in serum from mice treated with alkaloids and albendazole compared with the untreated control (1481 ± 619 pg/mL and 3.31 ± 0.37 IU/mL; P < 0.01). These results indicate that S. moorcroftiana alkaloids have protoscolicidal effects and the combination of alkaloids and albendazole has significant additive effects
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