252 research outputs found
Toric degenerations of projective varieties with an application to equivariant Hilbert functions
A toric degeneration is a flat family over that is trivial away from the special fiber (fiber over zero) and whose special fiber is a variety acted linearly by a torus with a dense orbit; i.e., the special fiber is a non-normal = not-necessarily-normal toric variety. We introduce a systematic method to construct toric degenerations of a projective variety (embedded up to Veronese embeddings). Part 1 develops the general theory of non-normal toric varieties by generalizing the more conventional theory of toric varieties. A new characterization of non-normal toric varieties as a complex of toric varieties is given. Given a projective variety of dimension , the main result of the thesis (Part 2) constructs a finite sequence of flat degenerations with irreducible and reduced special fibers such that the last one is a non-normal toric variety. The degeneration sequence depends on the choice of a full flag of closed subvarieties such that each is a \emph{good divisor} in . The notion of a good divisor comes from the asymptotic ideal theory in commutative algebra and the goodness ensures the finite generation of the defining graded ring of the special fiber in each step. This is a generalization of degeneration (or deformation) to normal cone in intersection theory and can be regarded as geometric reinterpretation of the construction of a valuation in \cite{Oko}, the key step in the construction of a Newton--Okounkov body. Part 3 reformulates the main result of \cite{Oko} in terms of an equivariant Hilbert function; this reformulation may be thought of as a special case of the equivariant Riemann--Roch theorem
Scalable Socket Buffer Tuning for High-Performance Web Servers
Although many research efforts have been devoted to network congestion in the face of an increase in the Internet traffic, there is little recent discussion on performance improvements for endhosts. In this paper, we propose a new architecture, called Scalable Socket Buffer Tuning (SSBT), to provide high-performance and fair service for many TCP connections at Internet endhosts. SSBT has two major features. One ist to reduce the number..
Numerical analysis of heat transfer characteristics of spray flames impinging on a wall under CI engine-like conditions
Design of Compression Ignition (CI) engines with improved thermal efficiencies needs better understanding of the heat transfer mechanism from spray flame to the combustion chamber wall. In this regard, heat transfer occurring during the interaction between impinging spray flame and wall, under CI engine-like conditions, is investigated in this study using 3-Dimensional numerical simulations based on an Eulerian–Lagrangian framework. Simulations are performed for different fuel spray injection velocities (which are representative of different fuel injection pressures in CI engines), to examine their influence on the heat transfer between impinging spray flame and wall. To couple the convective and radiative heat transfer at the wall surface with the conduction heat transfer occurring within the finite thickness wall, Conjugate Heat Transfer (CHT) is incorporated in the simulations. A Non-Adiabatic Flamelet/Progress Variable (NA-FPV) approach is employed as the combustion model of n-dodecane, which is considered to be the fuel for liquid spray. Dynamics of the liquid film formed on the wall surface by impinging fuel droplets are captured using a particle-based approach. Contribution of radiative heat flux is taken into consideration using the Discrete Ordinates (DO) method. Results indicate that the total heat flux (sum of convective and radiative heat fluxes) at the wall surface increases with the fuel injection velocity. It is observed that the total wall heat flux is largest in the stagnation zone where the spray flame impinges directly on the wall surface, while the radiative heat flux at the wall surface becomes larger as the distance from this stagnation zone increases. Additionally, it is found that the influence of fuel injection velocity on the radiative heat flow rate at the wall surface is rather small. This radiative heat flow rate when expressed as a percentage of the total wall heat flow rate, ranges from ≈ 18% to 30% (depending on the 3 cases investigated), indicating that its contribution cannot be neglected for the CI engine-like conditions under which the present simulations are performed. Furthermore, to characterize the heat transfer occurring during spray flame-wall interaction process, correlations between the Nusselt number Nu (corresponding to the wall heat loss) and Reynolds number Re (of the flow field) of the form Nu ∝ Re, are analysed and compared with that of a previous experimental study to assess their applicability. It is found that, depending on how the Nusselt number Nu is defined (either using the total wall heat flux or the convective heat flux), the value of the correlation index n changes. When Nu is calculated based on the total wall heat flux (which includes the contribution from the radiative heat flux), the value of n is found to be 0.49 which is close to the correlation index value of n = 0.4 reported in the recent experiments performed at Toyota Central R&D Labs., Inc
Photochemical Products from Ergosterol in the Plasma Membrane of the Yeast Rhodotorula minuta cells illuminated by Near-UV
When the plasma mumbrane of the yeast Rhodotorula minuta cells was exposed to near-UV at 0℃, three new compounds were formes photochemically with decrease in ergosterol content. When 0.4%-SDS solution containing ergosterol was illuminated with near-UV, the same three compounds as in the membrane were formed. As a result of instruments analysis, one of three photochemical products was identified as previtamine D2 and another two compounds were characterized chemically that they had the structure of ergosta-4, 7, 22-trein-3-on. In addition, these photochemical products did not affect the growth and carotenogenesis of the yeast Rhodotorulaminuta.赤色酵母R.minuta細胞膜に長波長紫外光を照射した時に生じるエルゴステロール由来の光化学反応生成物の単離・精製およびその同定を行った。結果、3種類の物質が単離・精製され、そのうち1つはPrevitamin D2であることが同定され、残りの2つについてはergosta-4,7,22-trien-3-on の何かの炭素にOH基が付いたものであることが分かった。単離した成分を培地に加え、菌体の増殖とカロテノイド生合成に対する影響を調べた結果、これらの物質はそのどちらにも影響を及ぼさなかった
Diffusion tensor model links to neurite orientation dispersion and density imaging at high b-value in cerebral cortical gray matter
Diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) are widely used models to infer microstructural features in the brain from diffusion-weighted MRI. Several studies have recently applied both models to increase sensitivity to biological changes, however, it remains uncertain how these measures are associated. Here we show that cortical distributions of DTI and NODDI are associated depending on the choice of b-value, a factor reflecting strength of diffusion weighting gradient. We analyzed a combination of high, intermediate and low b-value data of multi-shell diffusion-weighted MRI (dMRI) in healthy 456 subjects of the Human Connectome Project using NODDI, DTI and a mathematical conversion from DTI to NODDI. Cortical distributions of DTI and DTI-derived NODDI metrics were remarkably associated with those in NODDI, particularly when applied highly diffusion-weighted data (b-value = 3000 sec/mm2). This was supported by simulation analysis, which revealed that DTI-derived parameters with lower b-value datasets suffered from errors due to heterogeneity of cerebrospinal fluid fraction and partial volume. These findings suggest that high b-value DTI redundantly parallels with NODDI-based cortical neurite measures, but the conventional low b-value DTI is hard to reasonably characterize cortical microarchitecture
日本における精神科入院患者の自殺企図の特徴
Suicide is an adverse event that can occur even when patient are hospitalized in psychiatric facilities. This study delineates the demographic characteristics of suicide attempts in mental hospitals and psychiatric wards of general hospitals in Japan, a country where the suicide rate is remarkably high. Analyses of incident reports on serious suicide attempts in psychiatric inpatients were performed using prefectural incident records between April 1, 2001, and December31, 2012. Suicide reports were included for 35 incidents that occurred over 11years, and demonstrated that 83% of patients (n=29) committed suicide and 17% (n=6) survived their attempt with serious aftereffects, such as cognitive impairment or persistent vegetative state. The male/female ratio of inpatient suicide was 1.5:1. The mean age of the attempters was 50.5 years (SD = 18.2). The most common psychiatric diagnoses for those with suicide incident reports were schizophrenia spectrum disorders (51.4%) and affective disorders (40%). Hanging (60%) was the most common method of suicide attempt, followed by jumping in front of moving objects (14.3%) and jumping from height (11.4%). Fifty-four percent of suicides (n=19) occurred within hospital sites and the remainder (46%; n=16) occurred outside hospital sites (e.g., on medical leave or elopement) while they were still inpatients.博士(医学)・乙第1347号・平成26年12月3日© 2014 Ikeshita Katsumi et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Capsaicin May Improve Swallowing Impairment in Patients with Amyotrophic Lateral Sclerosis: A Randomized Controlled Trial
Patients with neurodegenerative diseases are at an increased risk of dysphagia and aspiration pneumonia. In this study, we examined whether ingestion of capsaicin prior to swallowing changes the temporal dynamics of swallowing in such patients. In a crossover, randomized controlled trial, 29 patients with neurodegenerative diseases were given a soluble wafer containing 1.5 μg capsaicin or an identical placebo 20 min prior to testing. For evaluation with video fluoroscopy (VF), patients consumed a barium-containing liquid plus thickening material. The durations of the latency, elevating and recovery periods of the hyoid were assessed from VF. Overall, no significant differences were observed in the duration of each period between capsaicin and placebo treatments. However, reductions in the latency and elevating periods were positively correlated with baseline durations. In subgroup analyses, that correlation was observed in patents with amyotrophic lateral sclerosis (ALS) but not in patients with Parkinson’s disease. The consumption of wafer paper containing capsaicin before the intake of food may be effective in patients with dysphagia related with certain neurodegenerative diseases, particularly ALS patients. Further studies will be needed to validate this finding
Methotrexate for the treatment of juvenile idiopathic arthritis: process to approval for JIA indication in Japan
Methotrexate (MTX), the primary treatment for the articular-type juvenile idiopathic arthritis (JIA), is effective and brings about radiological improvement. Patient compliance is good, and it is recognized that its known side effects, namely, disruption of liver function and induction of pulmonary lesions, are unlikely to be severe at the low MTX doses that are administered. In Japan, MTX was granted approval in 1999 by the then Ministry of Health and Welfare specifically for treating rheumatoid arthritis in adult patients, allowing it be generally used in medical institutions for patients having National Health Insurance. However, in the pediatric field, its use outside the indications has so far been unavoidable, and has been left to the discretion of the physician. Finally, at the present conference, expansion of the indications of MTX for JIA was approved in Japan. It is noteworthy that this expansion of indications was achieved without requiring clinical trials on children sponsored by the pharmaceutical company: it was achieved rather by collecting necessary information through ongoing efforts (including collection and analysis of information about approval status in foreign countries, adequate evidence from the literature, implementation of a clinical use survey in Japan, etc.). It also merits attention that the maximum dose (10 mg/m2) was set on the basis of pharmacokinetic data from children, rather than relying on the dosing method and dose for adults
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