291 research outputs found
Semiparametric Copula Estimation for Spatially Correlated Multivariate Mixed Outcomes: Analyzing Visual Sightings of Fin Whales from Line Transect Survey
Multivariate data having both continuous and discrete variables is known as
mixed outcomes and has widely appeared in a variety of fields such as ecology,
epidemiology, and climatology. In order to understand the probability structure
of multivariate data, the estimation of the dependence structure among mixed
outcomes is very important. However, when location information is equipped with
multivariate data, the spatial correlation should be adequately taken into
account; otherwise, the estimation of the dependence structure would be
severely biased. To solve this issue, we propose a semiparametric Bayesian
inference for the dependence structure among mixed outcomes while eliminating
spatial correlation. To this end, we consider a hierarchical spatial model
based on the rank likelihood and a latent multivariate Gaussian process. We
develop an efficient algorithm for computing the posterior using the Markov
Chain Monte Carlo. We also provide a scalable implementation of the model using
the nearest-neighbor Gaussian process under large spatial datasets. We conduct
a simulation study to validate our proposed procedure and demonstrate that the
procedure successfully accounts for spatial correlation and correctly infers
the dependence structure among outcomes. Furthermore, the procedure is applied
to a real example collected during an international synoptic krill survey in
the Scotia Sea of the Antarctic Peninsula, which includes sighting data of fin
whales (Balaenoptera physalus), and the relevant oceanographic data.Comment: 23 pages, 5 figure
Clusters die hard: Time-correlated excitation in the Hamiltonian Mean Field model
The Hamiltonian Mean Field (HMF) model has a low-energy phase where
particles are trapped inside a cluster. Here, we investigate some properties of
the trapping/untrapping mechanism of a single particle into/outside the
cluster. Since the single particle dynamics of the HMF model resembles the one
of a simple pendulum, each particle can be identified as a high-energy particle
(HEP) or a low-energy particle (LEP), depending on whether its energy is above
or below the separatrix energy. We then define the trapping ratio as the ratio
of the number of LEP to the total number of particles and the
``fully-clustered'' and ``excited'' dynamical states as having either no HEP or
at least one HEP. We analytically compute the phase-space average of the
trapping ratio by using the Boltzmann-Gibbs stable stationary solution of the
Vlasov equation associated with the limit of the HMF model. The
same quantity, obtained numerically as a time average, is shown to be in very
good agreement with the analytical calculation. Another important feature of
the dynamical behavior of the system is that the dynamical state changes
transitionally: the ``fully-clustered'' and ``excited'' states appear in turn.
We find that the distribution of the lifetime of the ``fully-clustered'' state
obeys a power law. This means that clusters die hard, and that the excitation
of a particle from the cluster is not a Poisson process and might be controlled
by some type of collective motion with long memory. Such behavior should not be
specific of the HMF model and appear also in systems where {\it itinerancy}
among different ``quasi-stationary'' states has been observed. It is also
possible that it could mimick the behavior of transient motion in molecular
clusters or some observed deterministic features of chemical reactions.Comment: 14 pages, 5 figure
Low-pressure-responsive heat-storage ceramics for automobiles
The accumulated heat energy of a heat-storage material is typically released overtime. If a heat-storage material could preserve its accumulated heat energy for a prolonged period, the applicability of such materials would be expanded greatly. Herein we report a newly fabricated heat-storage material that can store latent heat energy for a long period and release the heat energy upon demand by applying an extremely low pressure. This material is a block-type lambda trititanium pentoxide (block-type lambda-Ti3O5). The block-type lambda-phase accumulates a large heat energy of 237 kJ L-1 and exhibits a pressure-induced phase transition to beta trititanium pentoxide. The pressure-induced phase transition occurs by applying only several tens of bars, and half of the fraction transforms by 7 MPa (70 bar). Such a low-pressure-responsive heat-storage ceramic is effective to reuse excessive heat in automobiles or waste heat at industrial factories
Structural basis for the membrane association of ankyrinG via palmitoylation
Fujiwara, Y., Kondo, H., Shirota, M. et al. Structural basis for the membrane association of ankyrinG via palmitoylation. Sci Rep 6, 23981 (2016) doi:10.1038/srep2398
Renal failure caused by eyedrops containing phenylephrine in a case of retinopathy of prematurity
The patient was a low birth weight infant with a history of renal failure. She was referred to our department 29 days after birth to undergo fundus examination. She experienced renal failure after undergoing a mydriatic test and needed medical treatment. Eyedrops containing phenylephrine were instilled several times and additional drops were also instilled during the fundal examination using an eyelid retractor, therefore the blood concentration of the drug was elevated sufficiently to contract the renal vessels, ultimately inducing renal failure. The present case suggests that since the use of mydriatic eyedrops in low birth weight infants could induce renal failure, the following points should be considered : 1) Mydriatic eyedrops should be used with caution by monitoring mydriasis and avoiding excessive instillation 2) After instillation, the lacrimal region should be compressed to prevent the flow of mydriatic drops to the nasolacrimal canal and 3) Vital signs should be monitored to check the onset of any adverse reactions for 12 hours after fundal examination
マリアナ弧北端部の熱水活動域(日光海山)より単離した新規Epsilon-Proteobacteriaの諸性質
BE09-P99ポスター要旨 / ブルーアース2009(2009年3月12日~13日, 立教大学池袋キャンパス)http://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt05-18/
SOCS-1/SSI-1-Deficient NKT Cells Participate in Severe Hepatitis through Dysregulated Cross-Talk Inhibition of IFN-γ and IL-4 Signaling In Vivo
AbstractSuppressor of cytokine signaling-1 (SOCS-1), also known as STAT-induced STAT inhibitor-1 (SSI-1), is a negative feedback molecule for cytokine signaling, and its in vivo deletion induces fulminant hepatitis. However, elimination of the STAT1 or STAT6 gene or deletion of NKT cells substantially prevented severe hepatitis in SOCS-1-deficient mice, while administration of IFN-γ and IL-4 accelerated its development. SOCS-1 deficiency not only sustained IFN-γ/IL-4 signaling but also eliminated the cross-inhibitory action of IFN-γ on IL-4 signaling. These results suggest that SOCS-1 deficiency-induced persistent activation of STAT1 and STAT6, which would be inhibited by SOCS-1 under normal conditions, may induce abnormal activation of NKT cells, thus leading to lethal pathological changes in SOCS-1-deficient mice
Analysis of the Complete Open Reading Frame of Genotype 2b Hepatitis C Virus in Association with the Response to Peginterferon and Ribavirin Therapy
BACKGROUND AND AIMS: Patients infected with genotype 2b hepatitis C virus (HCV) generally can achieve favorable responses to pegylated-interferon plus ribavirin therapy (PEG-IFN/RBV). However, a proportion of patients show poorer responses and the correlation between viral sequence variation and treatment outcome remains unclear. METHODS: The pretreatment complete open reading frame (ORF) sequences of genotype 2b HCV determined by direct sequencing were investigated for correlation with the final outcome in a total of 60 patients. RESULTS: In this study group, 87.5% (14/16) of non-sustained virological response (non-SVR) patients (n = 16) were relapsers. Compared to sustained virological response (SVR) patients (n = 44), non-SVR patients were older and could not achieve prompt viral clearance after the therapy induction. Comparing each viral protein between the two groups, viral sequences were more diverse in SVR patients and that diversity was found primarily in the E1, p7, and NS5A proteins. In searching for specific viral regions associated with the final outcome, several regions in E2, p7, NS2, NS5A, and NS5B were extracted. Among these regions, part of the interferon sensitivity determining region (ISDR) was included. In these regions, amino acid substitutions were associated with the final outcome in an incremental manner, depending upon the number of substitutions. CONCLUSIONS: Viral sequences are more diverse in SVR patients than non-SVR patients receiving PEG-IFN/RBV therapy for genotype-2b HCV infection. Through systematic comparison of viral sequences, several specific regions, including part of the ISDR, were extracted as having significant correlation with the final outcome
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