168 research outputs found
Numerical study of the hadron-quark mixed phase
The Coulomb screening effect and the finite-size effect such as surface
tension are figured out in the hadron-quark deconfinement phase transition. We
study the mixed phase of the quark droplets immersed in hadron matter. We see
that the droplet phase is mechanically unstable if the surface tension is
strong enough. Once the Coulomb potential is properly taken into account, we
could effectively satisfy the condition for charge chemical equilibrium in the
Maxwell construction. As a result, we suggest the Maxwell construction revives
the physical meaning effectively.Comment: 4 pages, 4figures, proceeding of Phase Transitions in Strongly
Interacting Matter 18th International Nuclear Physics Divisional Conference
of the EPS (NPDC18)Europhysics Conferenc
The NEDD8 system is essential for cell cycle progression and morphogenetic pathway in mice
NEDD8/Rub1 is a ubiquitin (Ub)-like molecule that covalently ligates to target proteins through an enzymatic cascade analogous to ubiquitylation. This modifier is known to target all cullin (Cul) family proteins. The latter are essential components of Skp1/Cul-1/F-box protein (SCF)–like Ub ligase complexes, which play critical roles in Ub-mediated proteolysis. To determine the role of the NEDD8 system in mammals, we generated mice deficient in Uba3 gene that encodes a catalytic subunit of NEDD8-activating enzyme. Uba3−/− mice died in utero at the periimplantation stage. Mutant embryos showed selective apoptosis of the inner cell mass but not of trophoblastic cells. However, the mutant trophoblastic cells could not enter the S phase of the endoreduplication cycle. This cell cycle arrest was accompanied with aberrant expression of cyclin E and p57Kip2. These results suggested that the NEDD8 system is essential for both mitotic and the endoreduplicative cell cycle progression. β-Catenin, a mediator of the Wnt/wingless signaling pathway, which degrades continuously in the cytoplasm through SCF Ub ligase, was also accumulated in the Uba3−/− cytoplasm and nucleus. Thus, the NEDD8 system is essential for the regulation of protein degradation pathways involved in cell cycle progression and morphogenesis, possibly through the function of the Cul family proteins
Observation of finite excess noise in the voltage-biased quantum Hall regime as a precursor for breakdown
We performed noise measurements in a two-dimensional electron gas to
investigate the nonequilibrium quantum Hall effect (QHE) state. While excess
noise is perfectly suppressed around the zero-biased QHE state reflecting the
dissipationless electron transport of the QHE state, considerable finite excess
noise is observed in the breakdown regime of the QHE. The noise temperature
deduced from the excess noise is found to be of the same order as the energy
gap between the highest occupied Landau level and the lowest empty one.
Moreover, unexpected finite excess noise is observed at a finite source-drain
bias voltagesmaller than the onset voltage of the QHE breakdown, which
indicates finite dissipation in the QHE state and may be related to the
prebreakdown of the QHE.Comment: 8 pages, 8 figure
A catalogue of name-bearing type specimens of fossil Bivalvia (Mollusca) registered in the Tohoku University Museum
A Countermeasure Method Using Poisonous Data Against Poisoning Attacks on IoT Machine Learning
In the modern world, several areas of our lives can be improved, in the form of diverse additional dimensions, in terms of quality, by machine learning. When building machine learning models, open data are often used. Although this trend is on the rise, the monetary losses since the attacks on machine learning models are also rising. Preparation is, thus, believed to be indispensable in terms of embarking upon machine learning. In this field of endeavor, machine learning models may be compromised in various ways, including poisoning attacks. Assaults of this nature involve the incorporation of injurious data into the training data rendering the models to be substantively less accurate. The circumstances of every individual case will determine the degree to which the impairment due to such intrusions can lead to extensive disruption. A modus operandi is proffered in this research as a safeguard for machine learning models in the face of the poisoning menace, envisaging a milieu in which machine learning models make use of data that emanate from numerous sources. The information in question will be presented as training data, and the diversity of sources will constitute a barrier to poisoning attacks in such circumstances. Every source is evaluated separately, with the weight of each data component assessed in terms of its ability to affect the precision of the machine learning model. An appraisal is also conducted on the basis of the theoretical effect of the use of corrupt data as from each source. The extent to which the subgroup of data in question can undermine overall accuracy depends on the estimated data removal rate associated with each of the sources described above. The exclusion of such isolated data based on this figure ensures that the standard data will not be tainted. To evaluate the efficacy of our suggested preventive measure, we evaluated it in comparison with the well-known standard techniques to assess the degree to which the model was providing accurate conclusions in the wake of the change. It was demonstrated during this test that when the innovative mode of appraisal was applied, in circumstances in which 17% of the training data are corrupt, the degree of precision offered by the model is 89%, in contrast to the figure of 83% acquired through the traditional technique. The corrective technique suggested by us thus boosted the resilience of the model against harmful intrusion
Finite size effects on kaonic pasta structures
Non-uniform structures of mixed phases at the first-order phase transition to
charged kaon condensation are studied using a density functional theory within
the relativistic mean field model. Including electric field effects and
applying the Gibbs conditions in a proper way, we numerically determine density
profiles of nucleons, electrons and condensed kaons. Importance of charge
screening effects is elucidated and thereby we show that the Maxwell
construction is effectively justified. Surface effect is also studied to figure
out its effect on the density profiles
Two Distinct Pathways Mediated by PA28 and hsp90 in Major Histocompatibility Complex Class I Antigen Processing
Major histocompatibility complex (MHC) class I ligands are mainly produced by the proteasome. Herein, we show that the processing of antigens is regulated by two distinct pathways, one requiring PA28 and the other hsp90. Both hsp90 and PA28 enhanced the antigen processing of ovalbumin (OVA). Geldanamycin, an inhibitor of hsp90, almost completely suppressed OVA antigen presentation in PA28α−/−/β−/− lipopolysaccharide blasts, but not in wild-type cells, indicating that hsp90 compensates for the loss of PA28 and is essential in the PA28-independent pathway. In contrast, treatment of cells with interferon (IFN)-γ, which induces PA28 expression, abrogated the requirement of hsp90, suggesting that IFN-γ enhances the PA28-dependent pathway, whereas it diminishes hsp90-dependent pathway. Importantly, IFN-γ did not induce MHC class I expressions in PA28-deficient cells, indicating a prominent role for PA28 in IFN-γ–stimulated peptide supply. Thus, these two pathways operate either redundantly or specifically, depending on antigen species and cell type
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