241 research outputs found
Stationary Vacuum Bubble in a Kerr-de Sitter Spacetime
We study false vacuum decay in a black hole (BH) spacetime with an angular
momentum. Considering the false vacuum region described by a Kerr-de Sitter
geometry, under the thin wall approximation, we can obtain the stationary
configuration of the vacuum bubble seen from the outside false vacuum region
without specifying the geometry inside the domain wall. Then, assuming the true
vacuum region is described by a Kerr geometry, we can fix the mass and the spin
parameter for the Kerr geometry by imposing the 1st junction conditions and
conservation of the angular momentum. Although the assumption of the Kerr
geometry inside the domain wall cannot be fully consistent with the 2nd
junction conditions, we can roughly evaluate the error associated with this
inconsistency by calculating the Brown-York quasi-local energy on the domain
wall. Then the decay rate can be estimated by using the obtained parameters for
the inside Kerr geometry and the Brown-York quasi-local energy. Our results
support the statement that the BH spin suppresses the false vacuum decay in a
BH spacetime.Comment: 17 pages, 8 figures; v2:accepted for publication in Phys. Rev.
Boosting for Bounding the Worst-class Error
This paper tackles the problem of the worst-class error rate, instead of the
standard error rate averaged over all classes. For example, a three-class
classification task with class-wise error rates of 10\%, 10\%, and 40\% has a
worst-class error rate of 40\%, whereas the average is 20\% under the
class-balanced condition. The worst-class error is important in many
applications. For example, in a medical image classification task, it would not
be acceptable for the malignant tumor class to have a 40\% error rate, while
the benign and healthy classes have 10\% error rates.We propose a boosting
algorithm that guarantees an upper bound of the worst-class training error and
derive its generalization bound. Experimental results show that the algorithm
lowers worst-class test error rates while avoiding overfitting to the training
set
Spins of primordial black holes formed with a soft equation of state
We investigate the probability distribution of the spins of primordial black
holes (PBHs) formed in the universe dominated by a perfect fluid with the
linear equation of state , where and are the pressure and
energy density of the fluid, respectively. We particularly focus on the
parameter region since the larger value of the spin is expected
for the softer equation of state than that of the radiation fluid ().
The angular momentum inside the collapsing region is estimated based on the
linear perturbation equation at the turn-around time which we define as the
time when the linear velocity perturbation in the conformal Newtonian gauge
takes the minimum value. The probability distribution is derived based on the
peak theory with the Gaussian curvature perturbation. We find that the root
mean square of the non-dimensional Kerr parameter is approximately proportional to
, where and are the mass of
the PBH and the horizon mass at the horizon entry, respectively. Therefore the
typical value of the spin parameter decreases with the value of . We also
evaluate the mass and spin distribution , taking account of the
critical phenomena. We find that, while the spin is mostly distributed in the
range of for the radiation-dominated
universe, the peak of the spin distribution is shifted to the larger range
for .Comment: 20 pages, 6 figure
Single cell analysis of neutrophils NETs by Microscopic LSPR imaging system
A simple microengraving cell monitoring method for neutrophil extracellular traps
(NETs) released from single neutrophils has been realized using a polydimethylsiloxane (PDMS)
microwell array (MWA) sheet on a plasmon chip platform. An imbalance between NETs formation
and the succeeding degradation (NETosis) are considered associated with autoimmune disease and
its pathogenesis. Thus, an alternative platform that can conduct monitoring of this activity on single
cell level at minimum cost but with great sensitivity is greatly desired. The developed MWA
plasmon chips allow single cell isolation of neutrophils from 150 μL suspension (6.0 × 105 cells/mL)
with an efficiency of 36.3%; 105 microwells with single cell condition. To demonstrate the utility of
the chip, trapped cells were incubated between 2 to 4 h after introducing with 100 nM phorbol 12-
myristate 13-acetate (PMA) before measurement. Under observation using a hyperspectral imaging
system that allows high-throughput screening, the neutrophils stimulated by PMA solution show a
significant release of fibrils and NETs after 4 h, with observed maximum areas between 314–758
μm2. An average absorption peak wavelength shows a redshift of Δλ = 1.5 nm as neutrophils release
NETs
Effect of Mix Cropping of Determinate and Indeterminate Soybean Lines on Canopy Structure in Kawatabi Field Center in 2017
Poster Session
Effect of Mix Cropping of Determinate and Indeterminate Lines on Sink-Source Balance in Soybean Grown in Kawatabi Field Center
Poster Session
Inflammatory Cytokine Gene Expression in Mesenteric Adipose Tissue during Acute Experimental Colitis
BACKGROUND: Production of inflammatory cytokines by mesenteric adipose tissue (MAT) has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Animal models of colitis have demonstrated inflammatory changes within MAT, but it is unclear if these changes occur in isolation or as part of a systemic adipose tissue response. It is also unknown what cell types are responsible for cytokine production within MAT. The present study was designed to determine whether cytokine production by MAT during experimental colitis is depot-specific, and also to identify the source of cytokine production within MAT.
METHODS: Experimental colitis was induced in 6-month-old C57BL/6 mice by administration of dextran sulfate sodium (2% in drinking water) for up to 5 days. The induction of cytokine mRNA within various adipose tissues, including mesenteric, epididymal, and subcutaneous, was analyzed by qRT-PCR. These adipose tissues were also examined for histological evidence of inflammation. The level of cytokine mRNA during acute colitis was compared between mature mesenteric adipocytes, mesenteric stromal vascular fraction (SVF), and mesenteric lymph nodes.
RESULTS: During acute colitis, MAT exhibited an increased presence of infiltrating mononuclear cells and fibrotic structures, as well as decreased adipocyte size. The mRNA levels of TNF-α, IL-1β, and IL-6 were significantly increased in MAT but not other adipose tissue depots. Within the MAT, induction of these cytokines was observed mainly in the SVF.
CONCLUSIONS: Acute experimental colitis causes a strong site-specific inflammatory response within MAT, which is mediated by cells of the SVF, rather than mature adipocytes or mesenteric lymph nodes
Ruthenium Picolinate Complex as a Redox Photosensitizer With Wide-Band Absorption
Ruthenium(II) picolinate complex, [Ru(dmb)2(pic)]+ (Ru(pic); dmb = 4,4′-dimethyl-2,2′-bipyridine; Hpic = picolinic acid) was newly synthesized as a potential redox photosensitizer with a wider wavelength range of visible-light absorption compared with [Ru(N∧N)3]2+ (N∧N = diimine ligand), which is the most widely used redox photosensitizer. Based on our investigation of its photophysical and electrochemical properties, Ru(pic) was found to display certain advantageous characteristics of wide-band absorption of visible light (λabs < 670 nm) and stronger reduction ability in a one-electron reduced state (E1/2red = −1.86 V vs. Ag/AgNO3), which should function favorably in photon-absorption and electron transfer to the catalyst, respectively. Performing photocatalysis using Ru(pic) as a redox photosensitizer combined with a Re(I) catalyst reduced CO2 to CO under red-light irradiation (λex > 600 nm). TONCO reached 235 and ΦCO was 8.0%. Under these conditions, [Ru(dmb)3]2+ (Ru(dmb)) is not capable of working as a redox photosensitizer because it does not absorb light at λ > 560 nm. Even in irradiation conditions where both Ru(pic) and Ru(dmb) absorb light (λex > 500 nm), using Ru(pic) demonstrated faster CO formation (TOFCO = 6.7 min−1) and larger TONCO (2347) than Ru(dmb) (TOFCO = 3.6 min−1; TONCO = 2100). These results indicate that Ru(pic) is a superior redox photosensitizer over a wider wavelength range of visible-light absorption
Manuel Antunes (1918-1985) A rara excelência de um mestre exemplar
Breve biografia de Manuel Antunes (1918-1985) enquanto docente e investigador da Faculdade de Letras da Universidade de Lisboa.info:eu-repo/semantics/publishedVersio
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