948 research outputs found
Non-thermal radiation of black hole off canonical typicality
We study the Hawking radiation of black holes by considering the canonical
typicality. For the universe consisting of black holes and their outer part, we
directly obtain a non-thermal radiation spectrum of an arbitrary black hole
from its entropy, which only depends on a few external qualities (known as
hairs), such as mass, charge, and angular momentum. Our result shows that the
spectrum of the non-thermal radiation is independent of the detailed quantum
tunneling dynamics across black hole horizon. We prove that the black hole
information paradox is naturally resolved by taking account the correlation
between black hole and its radiation in our approach.Comment: 5 pages, 1 figure, pulished on Europhysics Letters, comments are
welcome
Positive solutions to a system of adjointable operator equations over Hilbert C∗-modules
AbstractWe present necessary and sufficient conditions for the existence of a positive solution to the system of adjointable operator equations A1X=C1,XB2=C2,A3XB3=C3 over Hilbert C∗-modules. We also derive a representation for a general positive solution to this system when the solvability conditions are satisfied. The results of this paper extend some known results in the literature
A gene-signature progression approach to identifying candidate small-molecule cancer therapeutics with connectivity mapping
Background: Gene expression connectivity mapping has gained much popularity recently with a number of successful applications in biomedical research testifying its utility and promise. Previously methodological research in connectivity mapping mainly focused on two of the key components in the framework, namely, the reference gene expression profiles and the connectivity mapping algorithms. The other key component in this framework, the query gene signature, has been left to users to construct without much consensus on how this should be done, albeit it has been an issue most relevant to end users. As a key input to the connectivity mapping process, gene signature is crucially important in returning biologically meaningful and relevant results. This paper intends to formulate a standardized procedure for constructing high quality gene signatures from a user’s perspective.Results: We describe a two-stage process for making quality gene signatures using gene expression data as initial inputs. First, a differential gene expression analysis comparing two distinct biological states; only the genes that have passed stringent statistical criteria are considered in the second stage of the process, which involves ranking genes based on statistical as well as biological significance. We introduce a “gene signature progression” method as a standard procedure in connectivity mapping. Starting from the highest ranked gene, we progressively determine the minimum length of the gene signature that allows connections to the reference profiles (drugs) being established with a preset target false discovery rate. We use a lung cancer dataset and a breast cancer dataset as two case studies to demonstrate how this standardized procedure works, and we show that highly relevant and interesting biological connections are returned. Of particular note is gefitinib, identified as among the candidate therapeutics in our lung cancer case study. Our gene signature was based on gene expression data from Taiwan female non-smoker lung cancer patients, while there is evidence from independent studies that gefitinib is highly effective in treating women, non-smoker or former light smoker, advanced non-small cell lung cancer patients of Asian origin.Conclusions: In summary, we introduced a gene signature progression method into connectivity mapping, which enables a standardized procedure for constructing high quality gene signatures. This progression method is particularly useful when the number of differentially expressed genes identified is large, and when there is a need to prioritize them to be included in the query signature. The results from two case studies demonstrate that the approach we have developed is capable of obtaining pertinent candidate drugs with high precision
Reanalysis of the Gross-Llewellyn Smith sum rule up to -order QCD corrections
In the paper, we reanalyze the properties of Gross-Llewellyn Smith (GLS) sum
rule by using the -order QCD corrections with the help
of principle of maximum conformality (PMC). By using the PMC single-scale
approach, we obtain an accurate renormalization scale-and-scheme independent
pQCD contribution for GLS sum rule, e.g. , where the error is squared average of those from
, the predicted -order terms
predicted by using the Pad\'{e} approximation approach. After applying the PMC,
a more convergent pQCD series has been obtained, and the contributions from the
unknown higher-order terms are highly suppressed. In combination with the
nonperturbative high-twist contribution, our final prediction of GLS sum rule
agrees well with the experimental data given by the CCFR collaboration.Comment: 6 pages, 5 figure
Observing white dwarf tidal stripping with TianQin gravitational wave observatory
Recently discovered regular X-ray bursts known as quasi-periodic eruptions
have a proposed model that suggests a tidal stripping white dwarf inspiralling
into the galaxy's central black hole on an eccentric orbit. According to this
model, the interaction of the stripping white dwarf with the central black hole
would emit gravitational wave signals as well, their detection can help explore
the formation mechanism of quasi-periodic eruptions and facilitate
multi-messenger observations. In this paper, we aim to perform a preliminary
study of the gravitation wave observation of TianQin on this stripping white
dwarf model. We investigated the horizon distance of TianQin on this type of
gravitation wave signal and found it can be set to 200Mpc. We also find that
those stripping white dwarf model sources with central black hole mass within
are more likely to be detected by TianQin. We
assessed the parameter estimation precision of TianQin on those stripping white
dwarf model sources. Our result shows that, even in the worst case, TianQin can
determine the central black hole mass, the white dwarf mass, the central black
hole spin, and the orbital initial eccentricity with a precision of .
In the optimistic case, TianQin can determine the central black hole mass and
the white dwarf mass with a precision of , determine the central black
hole spin with a precision of , and determine the orbital initial
eccentricity with a precision of . Moreover, TianQin can determine the
luminosity distance with a precision of and determine the sky
localization with a precision of .Comment: 9 pages, 4 figure
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