Bayesian image superresolution and hidden variable modeling

<正> Superresolution is an image processing technique that estimates an original high-resolutionimage from its low-resolution and degraded observations.In superresolution tasks,there have beenproblems regarding the computational cost for the estimation of high-dimensional variables.Theseproblems are now being overcome by the recent development of fast computers and the developmentof powerful computational techniques such as variational Bayesian approximation.This paper reviewsa Bayesian treatment of the superresolution problem and presents its extensions based on hierarchicalmodeling by employing hidden variables.     

Generalized Lévy walks and the role of chemokines in migration of effector CD8+ T cells

Chemokines have a central role in regulating processes essential to the immune function of T cells, such as their migration within lymphoid tissues and targeting of pathogens in sites of inflammation. Here we track T cells using multi-photon microscopy to demonstrate that the chemokine CXCL10 enhances the ability of CD8+ T cells to control the pathogen Toxoplasma gondii in the brains of chronically infected mice. This chemokine boosts T-cell function in two different ways: it maintains the effector T-cell population in the brain and speeds up the average migration speed without changing the nature of the walk statistics. Notably, these statistics are not Brownian; rather, CD8+ T-cell motility in the brain is well described by a generalized Lévy walk. According to our model, this unexpected feature enables T cells to find rare targets with more than an order of magnitude more efficiency than Brownian random walkers. Thus, CD8+ T-cell behaviour is similar to Lévy strategies reported in organisms ranging from mussels to marine predators and monkeys, and CXCL10 aids T cells in shortening the average time taken to find rare targets.     

K562 human leukaemic cells express fetal type (i) antigen on different glycoproteins from circulating erythrocytes

During the ontogenic change from fetal to adult human erythrocytes, as well as fetal haemoglobin being replaced by adult haemoglobin, the cell-surface antigen i is converted to I (ref. 1). Recently it has been shown that this antigenic change is the conversion of the linear repeating Gal beta 1 leads to 4GlcNac beta 1 leads to 3Gal structure to branched Gal beta 1 leads to 4GlcNac beta 1 leads to 3(Gal beta 1 leads to 4GlcNac beta 1 leads to 6)Gal structure. We have shown that cell-surface labelling followed by endo-beta-galactosidase digestion can distinguish these two forms on the cell surface, and that band 3 and band 4.5 are the major carriers for these antigens on mature erythrocytes. Human leukaemic cell line K562, originally isolated from a patient at blast crisis of chronic myelocytic leukaemia, has recently been shown to synthesize glycophorin A, and to be capable of synthesizing haemoglobin upon induction. I demonstrate here that K562 cells express the fetal type (i) antigen on distinctly different glycoproteins from those of erythrocytes, by the use of cell-surface labelling followed by endo-beta-galactosidase digestion or followed by immunoprecipitation with specific antibodies.     

Bifidobacteria can protect from enteropathogenic infection through production of acetate

The human gut is colonized with a wide variety of microorganisms, including species, such as those belonging to the bacterial genus Bifidobacterium, that have beneficial effects on human physiology and pathology. Among the most distinctive benefits of bifidobacteria are modulation of host defence responses and protection against infectious diseases. Nevertheless, the molecular mechanisms underlying these effects have barely been elucidated. To investigate these mechanisms, we used mice associated with certain bifidobacterial strains and a simplified model of lethal infection with enterohaemorrhagic Escherichia coli O157:H7, together with an integrated 'omics' approach. Here we show that genes encoding an ATP-binding-cassette-type carbohydrate transporter present in certain bifidobacteria contribute to protecting mice against death induced by E. coli O157:H7. We found that this effect can be attributed, at least in part, to increased production of acetate and that translocation of the E. coli O157:H7 Shiga toxin from the gut lumen to the blood was inhibited. We propose that acetate produced by protective bifidobacteria improves intestinal defence mediated by epithelial cells and thereby protects the host against lethal infection.     

Forecasting real‐time data allowing for data revisions

A modeling approach to real‐time forecasting that allows for data revisions is shown. In this approach, an observed time series is decomposed into stochastic trend, data revision, and observation noise in real time. It is assumed that the stochastic trend is defined such that its first difference is specified as an AR model, and that the data revision, obtained only for the latest part of the time series, is also specified as an AR model. The proposed method is applicable to the data set with one vintage. Empirical applications to real‐time forecasting of quarterly time series of US real GDP and its eight components are shown to illustrate the usefulness of the proposed approach. Copyright © 2007 John Wiley & Sons, Ltd.     

Cointegration rank switching model: an application to forecasting interest rates

This paper proposes a new forecasting method in which the cointegration rank switches at unknown times. In this method, time series observations are divided into several segments, and a cointegrated vector autoregressive model is fitted to each segment. The goodness of fit of the global model, consisting of local models with different cointegration ranks, is evaluated using the information criterion (IC). The division that minimizes the IC defines the best model. The results of an empirical application to the US term structure of interest rates and a Monte Carlo simulation suggest the efficacy as well as the limitations of the proposed method. Copyright © 2010 John Wiley & Sons, Ltd.     

超高层住宅空调负荷的模拟分析

文中通过模拟实验，将不同的空调使用方法、断热方法、建筑朝向和玻璃构造对超高层住宅构造墙蓄热的影响数字化，并进行了模拟分析．此次研究中所使用的模拟软件“THERB”（关于住宅温热环境的模拟软件）可以动态地模拟住宅中每个房间的温度、湿度、体感温度与冷暖房空调负荷，由于超高层住宅每个房间墙壁中构造墙体积的比率要大于普通住宅，而构造墙通常是由蓄热性很强的水泥筑成，因此水泥的蓄热性对超高层住宅的空调负荷会产生巨大的影响，也就是说，通过不同的空调使用方法、断热方法、建筑朝向和构造形态等对水泥构造墙蓄热情况的改变，超高层住宅的空调负荷也将随之改变．     

Heterogeneous responses of canine basilar and middle cerebral arteries to serotonin at normal and high CO2 tension.

The responses of basilar arteries (BAs) to serotonin were attenuated by high PCO2 (86 +/- 1 mm Hg) and the pH matched acidotic solution (PCO2 37 +/- 1 mm Hg), whereas the responses of middle cerebral arteries (MCAs) were not. High PCO2 decreased the basal tone of both arteries, and the changes in basal tone due to high PCO2 were not influenced by 3 x 10(-7) M imipramine, 10(-5) M pargyline or 10(-4) M aspirin. The responses of BAs to serotonin were attenuated by high PCO2 in the presence of imipramine, pargyline and aspirin. The responses of MCAs to serotonin were not influenced by high PCO2 in the presence of pargyline and aspirin, but attenuated by high PCO2 in the presence of imipramine.