221 research outputs found
On the cohomology of some exceptional symmetric spaces
This is a survey on the construction of a canonical or "octonionic K\"ahler"
8-form, representing one of the generators of the cohomology of the four
Cayley-Rosenfeld projective planes. The construction, in terms of the
associated even Clifford structures, draws a parallel with that of the
quaternion K\"ahler 4-form. We point out how these notions allow to describe
the primitive Betti numbers with respect to different even Clifford structures,
on most of the exceptional symmetric spaces of compact type.Comment: 12 pages. Proc. INdAM Workshop "New Perspectives in Differential
Geometry" held in Rome, Nov. 2015, to appear in Springer-INdAM Serie
Pre-quantization of the Moduli Space of Flat G-Bundles over a Surface
For a simply connected, compact, simple Lie group G, the moduli space of flat
G-bundles over a closed surface is known to be pre-quantizable at integer
levels. For non-simply connected G, however, integrality of the level is not
sufficient for pre-quantization, and this paper determines the obstruction --
namely a certain cohomology class in H^3(G^2;Z) -- that places further
restrictions on the underlying level. The levels that admit a pre-quantization
of the moduli space are determined explicitly for all non-simply connected,
compact, simple Lie groups G.Comment: 28 pages, 1 table, new version contains minor corrections, to be
published in Journal of Geometry and Physic
On Schubert's Problem of Characteristics
The Schubert varieties on a flag manifold G/P give rise to a cell
decomposition on G/P whose Kronecker duals, known as the Schubert classes on
G/P, form an additive base of the integral cohomology of G/P. The Schubert's
problem of characteristics asks to express a monomial in the Schubert classes
as a linear combination in the Schubert basis.
We present a unified formula expressing the characteristics of a flag
manifold G/P as polynomials in the Cartan numbers of the group G. As
application we develop a direct approach to our recent works on the Schubert
presentation of the cohomology rings of flag manifolds G/P.Comment: 27page
Feasibility of a new hollow fiber silicone membrane oxygenator for long-term ECMO application
Currently in United States, there are no clinically-applicable hollow fiber extracorporeal membrane oxygenation (ECMO) oxygenators available. Therefore, our laboratory is in the process of developing a silicone hollow fiber membrane oxygenator for long-term ECMO usage. This oxygenator incorporates an ultrathin silicone hollow fiber. At this time, a specially-modified blood flow distributor (one chamber distributor) is centered in the module to prevent blood stagnation. An ex vivo long-term durability test for ECMO was performed using a healthy miniature calf for 2 weeks. Venous blood was drained from the left jugular vein of a calf, passed through the oxygenator and infused into the left carotid artery using a Gyro C1E3 centrifugal blood pump. A successful 2-week ex vivo experiment was performed. The O2 and CO2 gas transfer rates were maintained at the same value of 40 ml/min at a blood flow rate of 1 L/min flow and V/Q=3 (V=gas flow rate Q=blood flow rate). The plasma free hemoglobin was maintained around 5 mg/dl. After the experiment, no blood clot formation was observed in the module and no abnormal necropsy findings were found. These data suggest that the performance of this newly-improved oxygenator was stable, reliable, and acceptable for long-term ECMO
Population‑based prostate‑specific antigen screening for prostate cancer may have an indirect effect on early detection through opportunistic testing in Kusatsu City, Shiga, Japan
Prostate cancer is the most common genitourinary cancer in men. Population-based serum prostate-specific antigen (PSA) testing is used to screen men for the early detection of asymptomatic prostate cancer. The present study compared the features of patients with prostate cancer in Kusatsu City, the only municipality in Shiga Prefecture of Japan to implement organized PSA screening, with those in other municipalities. The target population for organized PSA screening by mail invitation was men ≥50 years. Patients were pathologically diagnosed via prostate biopsy because of elevated serum PSA. This multicenter observational study was subsequently conducted in 14 hospitals. The following information was extracted from patient records: age, reason for PSA testing, initial PSA level, Gleason score, clinical stage, and place of residence. Risk classification was defined as low, intermediate, high, and advanced. Each patient was stratified according to their city/town. A total of 984 patients diagnosed with prostate cancer in Shiga in 2012 and 2017 were analyzed, of which 955 (97%) were opportunistically tested, with the remaining 29 (3%) assessed by organized screening. In Kusatsu, 93 patients were diagnosed, of whom 26 (28%) were detected by organized screening. By contrast, only three of 891 patients (0.3%) were detected by organized screening in other municipalities. Of patients in Kusatsu, cases identified by opportunistic testing had a higher initial PSA value (P=0.010) than those identified by organized screening. However, patients detected through opportunistic testing in Kusatsu City were younger (P=0.034), had a lower PSA value (P=0.001), and improved risk classification (P<0.001) than those in other municipalities. It was concluded that more patients were diagnosed with early-stage cancer by organized PSA screening. Furthermore, population-based PSA screening in Kusatsu City may have indirectly affected early detection, even by opportunistic testing
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