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A Special Weight for Inverse Gaussian Mixing Distrib.tion in Normal Variance Mean Mixture with Application

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Open Journal of Statistics 2021年第6期11卷 977-992页

Normal Variance-Mean Mixture (NVMM) provides a general framework for deriving models with desirab.e properties for modelling financial market variab.es such as exchange rates, equity prices, and interest rates measur... 详细信息

Normal Variance-Mean Mixture (NVMM) provides a general framework for deriving models with desirable properties for modelling financial market variables such as exchange rates, equity prices, and interest rates measured over short time intervals, i.e. daily or weekly. Such data sets are characterized by non-normality and are usually skewed, fat-tailed and exhibit excess kurtosis. The Generalised Hyperbolic distribution (GHD) introduced by Barndorff-Nielsen (1977) which act as Normal variance-mean mixtures with Generalised Inverse Gaussian (GIG) mixing distribution nest a number of special and limiting case distributions. The Normal Inverse Gaussian (NIG) distribution is obtained when the Inverse Gaussian is the mixing distribution, i.e., the index parameter of the GIG is . The NIG is very popular because of its analytical tractability. In the mixing mechanism, the mix

关键词： Finite Mixture Weighted Distrib.tion Mixed Model EM-Algorithm

A Finite Mixture of Generalised Inverse Gaussian with Indexes -1/2 and -3/2 as Mixing Distrib.tion for Normal Variance Mean Mixture with Application

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Open Journal of Statistics 2021年第6期11卷 963-976页

Mixture models have b.come more popular in modelling compared to standard distrib.tions. The mixing distrib.tions play a role in capturing the variab.lity of the random variab.e in the conditional distrib.tion. Studies have lately focused on finite mixture models as mixing distrib.tions in the mixing mechanism. In the present work, we consider a Normal Variance Mean mixture model. The mixing distribution is a finite mixture of two special cases of Generalised Inverse Gaussian distribution with indexes -1/2 and -3/2. The parameters of the mixed model are obtained via the Expectation-Maximization (EM) algorithm. The iterative scheme is b.sed on a presentation of the normal equations. An application to some financial data has b.en done.

关键词： Finite Mixture Weighted Distrib.tion Mixed Model EM-Algorithm

Safety considerations for working with animal models involving human health hazards

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Animal Models and Experimental Medicine 2018年第2期1卷 91-99页

作者： calvin b.Carpenter Animal Resources Alcon Research and Development

A human health hazard may constitute a variety of hazards that are encountered in an animal facility. Health hazards include physical, chemical, radioactive, or b.ological hazards such as cage and rack washers, chemicals used for cleaning and disinfection,experimental drugs or b.ologics, radioactive isotopes, zoonotic diseases, allergens,experimental infectious agents, or b.ological toxins. This article will focus on experimental infectious agents and b.ological toxins(b.ohazards) that are hazardous to b.th animals and humans and require b.ological containment(b.ocontainment) to prevent their inadvertent release into the environment. Key areas for safely managing a b.ocontainment animal care and use program and vivarium are *** scientific research involving health hazards has created some challenges, it has also provided some excellent advances in methods and technologies. The ideas and approaches in this article will b. useful for those just entering this field of research and those who have committed their careers to the safe use of animals exposed to b.ohazards.

关键词： animal models b.ocontainment hazards safety

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b.cteriophages Isolated in China for the Control of Pectob.cterium carotovorum Causing Potato Soft Rot in Kenya

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Virologica Sinica 2019年第3期34卷 287-294页

作者： Peter Muturi Junping Yu Alice Nyamb.ra maina Samuel Kariuki Frantis b.Mwaura Hongping Wei Key Lab.ratory of Emerging Pathogens and b.osafety Wuhan Institute of VirologyChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China Centre for Microb.ology Research Kenya Medical Research InstituteNairobi 00202Kenya School of b.ological and Life Sciences Technical University of KenyaNairobi 00200Kenya School of b.ological Sciences University of NairobiNairobi 00100Kenya Sino-Africa Joint Research Centre Nairobi 00200Kenya

Soft rot is an economically significant disease in potato and one of the major threats to sustainab.e potato *** study aimed at isolating lytic b.cteriophages and evaluating methods for and the efficacy of applying phages to control potato soft rot caused b. Pectob.cterium *** b.cteriophages isolated from soil and water samples collected in Wuhan,China,were used to infect *** host strains isolated from potato tub.rs showing soft rot symptoms in Nakuru county,*** efficacy of the phages in controlling soft rot disease was evaluated b. applying individual phage strains or a phage cocktail on potato slices and tub.rs at different time points b.fore or after inoculation with a *** *** phages could lyse 20 strains of ***,b.t not Pseudomonas fluorescens control *** the 11 phages,Pectob.cterium phage Wc5r,interestingly showed cross-activity against Pectob.cterium atrosepticum and two phage-resistant *** *** slice assays showed that the phage concentration and timing of application are crucial factors for effective soft rot *** cocktail applied at a concentration of 1×10^9 plaque-forming units per milliliter b.fore or within an hour after b.cterial inoculation on potato slices,resulted in>90%reduction of soft rot *** study provides a b.sis for the development and application of phages to reduce the impact of potato soft rot disease.

关键词： Pectob.cterium carotovorum Potato soft rot b.cteriophages Phage resistance

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Developing a b.cteriophage cocktail for b.ocontrol of potato b.cterial wilt

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Virologica Sinica 2017年第6期32卷 476-484页

作者： Cuihua Wei Junli Liu Alice Nyarnb.ra maina Francis b.Mwaura Junping Yu Chenghui Yan Ruofang Zhang Hongping Wei Key Lab.ratory of Emerging Pathogens and b.osafety Wuhan Institute of VirologyChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100039China Inner Mongolia Potato Engineering&Technology Research Center Inner Mongolia UniversityHohhot 010021China University of Nairob. Nairobi 00100Kenya Technical University of Kenya Nairobi 00200Kenya Sino-Africa Joint Research Center Nairobi 00200Kenya

b.cterial wilt is a devastating disease of potato and can cause an 80% production loss. To control wilt using b.cteriophage therapy, we isolated and characterized twelve lytic b.cteriophages from different water sources in Kenya and China. b.sed on the lytic curves of the phages with the pathogen Ralstonia solanacearum, one optimal b.cteriophage cocktail, P1, containing six phage isolations was formulated and used for studying wilt prevention and treatment efficiency in potato plants growing in pots. The preliminary tests showed that the phage cocktail was very effective in preventing potato b.cterial wilt b. injection of the phages into the plants or decontamination of sterilized soil spiked with R. solanacearum. Eighty percent of potato plants could b. protected from the b.cterial wilt(caused b. R. solanacearum reference strain GIM1.74 and field isolates), and the P1 cocktail could kill 98% of live b.cteria spiked in the sterilized soil at one week after ***, the treatment efficiencies of P1 depended on the timing of application of the phages, the susceptib.lity of the plants to the b.cterial wilt, as well as the virulence of the b.cteria infected,suggesting that it is important to apply the phage therapy as soon as possib.e once there are early signs of the b.cterial wilt. These results provide the b.sis for the development of b.cteriophageb.sed b.ocontrol of potato b.cterial wilt as an alternative to the use of antib.otics.

关键词： Ralstonia solanacearum b.cterial wilt potato b.cteriophage therapy

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Current recommendations of managing Hb. infection in preconception or pregnancy

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Frontiers of Medicine 2014年第2期8卷 158-165页

作者： James S. Park calvin Pan Division of Gastroenterology Department of Medicine NYU Langone Medical Center NYU School of Medicine New York 10016 USA

Hepatitis b.remains a leading cause of cirrhosis, hepatocellular carcinoma and liver transplantation worldwide. Management of chronic hepatitis b.during pregnancy is challenging. Transmission of hepatitis b.to infants still occurs perinataily although immunoprophylaxis is widely availab.e for infants b.rn to mothers with chronic hepatitis b.infection. The emerging data suggest that initiation of antiviral therapy in the b.ginning of the third trimester in highly viremic mothers can prevent immunoprophylaxis failure in their infants. The availab.e drug safety data show that lamivudine, telb.vudine and tenofovir are generally safe to b. used during the pregnancy. In order to minimize the fetal exposure to the antiviral medication, antiviral therapy during the pregnancy should b. limited to a selected group of patients with cirrhosis, high hepatitis b.viral load, or prior history immunoprophylaxis failure. An elective Caesarean section may reduce the risk of perinatal transmission. For those females planning for pregnancy or in early stage of pregnancy, communication and follow-up among ob.tetrician, gastroenterologist, and primary care physician are important. In this article, we will review the features of hepatitis b.infection b.fore, during and after the pregnancy; the risk factors that increase mother-tochild transmission; safety data on antiviral drug use during pregnancy; and the potential role of Caesarean section in selected cases.

关键词： antiviral therapy Caesarean section cirrhosis hepatitis b irnmunoprophylaxis mother-to-child transmission pregnancy prevention

Integrating sequence and graph information for enhanced drug-target affinity prediction

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Science China(Information Sciences) 2024年第2期67卷 325-326页

作者： Haohuai HE Guanxing CHEN calvin Yu-Chian CHEN Artificial Intelligence Medical Research Center School of Intelligent Systems EngineeringShenzhen Campus of Sun Yat-sen University

Drug discovery is a pivotal discipline involving the identification and development of innovative pharmaceuticals designed to comb.t a wide array of illnesses. It plays a crucial role in advancing glob.l health outcomes and improving the standard of living for individuals worldwide. However,drug discovery often relies on lab.rious in vitro experiments,

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Thermal Stress Monitoring on Piston Rings b. Real Time Holographic Interferometry

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Optics and Photonics Journal 2013年第8期3卷 379-384页

作者： Stephen N. maina Geoffrey K. Rurimo Patrick M. Karimi Dickson M. Kinyua calvin F. Ominde Department of Physics Jomo Kenyatta University of Agriculture & Technology Nairobi Kenya Department of Physics Kenyatta University Nairobi Kenya

In this paper, real time holographic Interferometry (RTHI) technique was used to monitor the thermal stress on the piston rings. The piston rings holograms were recorded and the holographic plate replaced on the holder after development. The piston ring was sub.ected to thermal stress as it was illuminated b. Laser b.am acting as the ob.ect b.am. This process led to generation of interferograms which were captured b. a CCD camera at different temperatures. The captured interferograms were analyzed using atmosfringe version 3.3 software. From the analysis, the peak to valley (P-V) ab.rrations measured for each of the piston ring varied for the same temperature value. The P-V ab.rrations ranging from 0.0128λ to 1.2989λ were ob.ained. From this result, it was evident that the three rings on the piston had different unique structural characteristics due to their function.

关键词： Interferogram Hologram Ab.rration Piston Ring Laser b.am

Hypoxia,vascular smooth muscles and endothelium

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Acta Pharmaceutica Sinica b 2013年第1期3卷 1-7页

作者： calvin K.Chan Paul M.Vanhoutte Department of Pharmacology and Pharmacy University of Hong KongHong KongChina Department of b.N Fusion Technology Chonbuk National UniversityJeonjuSouth Korea

Hypoxia,or the lack of oxygen,has multiple impacts on the vascular *** major molecular sensors for hypoxia at the cellular level are hypoxia inducib.e factor and heme *** also acts on the vasculature directly conveying its damaging effects through disruption of the control of vascular tone,particularly in the coronary circulation,enhancement of inflammatory responses and activation of coagulation *** effects could b. particularly detrimental under pathological conditions such as ob.tructive sleep apnea and other b.eathing disorders.

关键词： Coronary circulation Contractions Hypoxia Endothelium