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101.
Poisson integer‐valued auto‐regressive process of order 1 (PINAR(1)) due to Al‐Osh and Alzaid (Journal of Time Series Analysis 1987; 8 (3): 261–275) and McKenzie (Advances in Applied Probability 1988; 20 (4): 822–835) has received a significant attention in modelling low‐count time series during the last two decades because of its simplicity. But in many practical scenarios, the process appears to be inadequate, especially when data are overdispersed in nature. This overdispersion occurs mainly for three reasons: presence of some extreme values, large number of zeros, and presence of both extreme values with a large number of zeros. In this article, we develop a zero‐inflated Poisson INAR(1) process as an alternative to the PINAR(1) process when the number of zeros in the data is larger than the expected number of zeros by the Poisson process. We investigate some important properties such as stationarity, ergodicity, autocorrelation structure, and conditional distribution, with a detailed study on h‐step‐ahead coherent forecasting. A comparative study among different methods of parameter estimation is carried out using some simulated data. One real dataset is analysed for practical illustration. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
102.
Chambers JC Zhang W Sehmi J Li X Wass MN Van der Harst P Holm H Sanna S Kavousi M Baumeister SE Coin LJ Deng G Gieger C Heard-Costa NL Hottenga JJ Kühnel B Kumar V Lagou V Liang L Luan J Vidal PM Mateo Leach I O'Reilly PF Peden JF Rahmioglu N Soininen P Speliotes EK Yuan X Thorleifsson G Alizadeh BZ Atwood LD Borecki IB Brown MJ Charoen P Cucca F Das D de Geus EJ Dixon AL Döring A Ehret G Eyjolfsson GI Farrall M Forouhi NG Friedrich N Goessling W Gudbjartsson DF Harris TB Hartikainen AL Heath S 《Nature genetics》2011,43(11):1131-1138
Concentrations of liver enzymes in plasma are widely used as indicators of liver disease. We carried out a genome-wide association study in 61,089 individuals, identifying 42 loci associated with concentrations of liver enzymes in plasma, of which 32 are new associations (P = 10(-8) to P = 10(-190)). We used functional genomic approaches including metabonomic profiling and gene expression analyses to identify probable candidate genes at these regions. We identified 69 candidate genes, including genes involved in biliary transport (ATP8B1 and ABCB11), glucose, carbohydrate and lipid metabolism (FADS1, FADS2, GCKR, JMJD1C, HNF1A, MLXIPL, PNPLA3, PPP1R3B, SLC2A2 and TRIB1), glycoprotein biosynthesis and cell surface glycobiology (ABO, ASGR1, FUT2, GPLD1 and ST3GAL4), inflammation and immunity (CD276, CDH6, GCKR, HNF1A, HPR, ITGA1, RORA and STAT4) and glutathione metabolism (GSTT1, GSTT2 and GGT), as well as several genes of uncertain or unknown function (including ABHD12, EFHD1, EFNA1, EPHA2, MICAL3 and ZNF827). Our results provide new insight into genetic mechanisms and pathways influencing markers of liver function. 相似文献
103.
Sansone SA Rocca-Serra P Field D Maguire E Taylor C Hofmann O Fang H Neumann S Tong W Amaral-Zettler L Begley K Booth T Bougueleret L Burns G Chapman B Clark T Coleman LA Copeland J Das S de Daruvar A de Matos P Dix I Edmunds S Evelo CT Forster MJ Gaudet P Gilbert J Goble C Griffin JL Jacob D Kleinjans J Harland L Haug K Hermjakob H Ho Sui SJ Laederach A Liang S Marshall S McGrath A Merrill E Reilly D Roux M Shamu CE Shang CA Steinbeck C Trefethen A Williams-Jones B Wolstencroft K Xenarios I 《Nature genetics》2012,44(2):121-126
To make full use of research data, the bioscience community needs to adopt technologies and reward mechanisms that support interoperability and promote the growth of an open 'data commoning' culture. Here we describe the prerequisites for data commoning and present an established and growing ecosystem of solutions using the shared 'Investigation-Study-Assay' framework to support that vision. 相似文献
104.
Park D Han CZ Elliott MR Kinchen JM Trampont PC Das S Collins S Lysiak JJ Hoehn KL Ravichandran KS 《Nature》2011,477(7363):220-224
Rapid and efficient removal of apoptotic cells by phagocytes is important during development, tissue homeostasis and in immune responses. Efficient clearance depends on the capacity of a single phagocyte to ingest multiple apoptotic cells successively, and to process the corpse-derived cellular material. However, the factors that influence continued clearance by phagocytes are not known. Here we show that the mitochondrial membrane potential of the phagocyte critically controls engulfment capacity, with lower potential enhancing engulfment and vice versa. The mitochondrial membrane protein Ucp2, which acts to lower the mitochondrial membrane potential, was upregulated in phagocytes engulfing apoptotic cells. Loss of Ucp2 reduced phagocytic capacity, whereas Ucp2 overexpression enhanced engulfment. Mutational and pharmacological studies indicated a direct role for Ucp2-mediated mitochondrial function in phagocytosis. Macrophages from Ucp2-deficient mice were impaired in phagocytosis in vitro, and Ucp2-deficient mice showed profound in vivo defects in clearing dying cells in the thymus and testes. Collectively, these data indicate that mitochondrial membrane potential and Ucp2 are key molecular determinants of apoptotic cell clearance. As Ucp2 is linked to metabolic diseases and atherosclerosis, this newly discovered role for Ucp2 in apoptotic cell clearance has implications for the complex aetiology and pathogenesis of these diseases. 相似文献
105.
微线圈阵列和匹配电容谐振可以实现植入电刺激器多路信息的并行传输。为提高微线圈阵列接收各通道信息的精确性与可靠性,并减小植入系统的体积,实验中利用印刷电路板(printedcircuit board,PCB)和柔性电路板(flexible printed circuit,FPC),工艺加工微线圈阵列,将其用于2*2阵列的多通道传输装置,并测试2种工艺线圈在理想耦合、空间失配以及不同负载下的耦合效率情况。结果表明空间失配对两种线圈都有影响,但若控制横向失配在3 mm内、角度失配在30度内,并增大负载,目前实验室阶段2种线圈均可实现植入电刺激器信号的透皮传输,各通道输出信号能满足神经电刺激的要求。在系统可靠性方面,FPC线圈更具有优势,且其柔性的特点更适于植入人体。 相似文献
106.
Cu–graphene (Gr) composite thin films were prepared by electrodeposition route using in-house synthesized Gr sheets. The Gr sheets were synthesized by the electrochemical exfoliation route using 1 M HClO4 acid as electrolyte. The Gr sheets were confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). The (002) plane of Gr sheets was observed at 2θ of 25.66°. The (002) plane confirmed the crystal structure of carbon peaks. The stretching vibration of C=C bond at a wavelength of 1577 cm?1 and other functional groups of carboxyl and epoxide groups were observed from FTIR. TEM confirmed the transparent structure of Gr sheets. The prepared Gr sheets were used as reinforcement at concentrations of 0.1 and 0.3 g/L with a copper matrix to synthesize the Cu–Gr composite. The prepared composite thin films were characterized by XRD, SEM, and energy-dispersion spectrometry (EDS) for morphological and analytical studies. The presence of Gr sheets in Cu–Gr composite was confirmed by EDS analysis. The prepared Cu–Gr nanocomposite thin film showed higher corrosion resistance compared with pure copper thin films in 3.5wt% NaCl, as confirmed by Tafel plots. Electrochemical impedance spectroscopy complimented the above results and showed that 0.3 g/L composite film achieved the highest film resistance. 相似文献
107.
S. Das Gupta M. V. Moorthy B. L. Chowdhri A. K. Ghosh 《Cellular and molecular life sciences : CMLS》1979,35(2):249-250
Summary The biological half-life of 2-PAM.Cl was found to increase in female rats pretreated with thiamine hydrochloride (10 mg/kg i.m.). No such effect was observed in the male rats.Dr B.L. Chowdhri very kindly synthesized the compound 2-PAM.Cl in the Department of Chemistry of this establishment for this work.The authors are thankful to Dr P.K. Ramachandran, Director, and Dr A.K. Chatterjee, Deputy Director, Defence Research and Development Establishment, Gwalior, for their keen interest in this work. 相似文献
108.
Zusammenfassung Wiederholte Applikation von Äthynitroso-Harnstoff bei trächtigen Ratten bewirkt bei Föten eine Hemmung der Gehirnentwicklung, wobei vor allem die hemisphären und das Cerebellum unterentwickelt bleiben. Diese Hemmung ist am ausgeprägtesteniw wenn die Behandlung am 14. Tag der Trächtigkeit einsetzt. 相似文献
109.
110.