308 research outputs found
Numerical Strategies of Computing the Luminosity Distance
We propose two efficient numerical methods of evaluating the luminosity
distance in the spatially flat {\Lambda}CDM universe. The first method is based
on the Carlson symmetric form of elliptic integrals, which is highly accurate
and can replace numerical quadratures. The second method, using a modified
version of Hermite interpolation, is less accurate but involves only basic
numerical operations and can be easily implemented. We compare our methods with
other numerical approximation schemes and explore their respective features and
limitations. Possible extensions of these methods to other cosmological models
are also discussed.Comment: 4 pages, 2 figures. v2: A minor error in the last equation has been
corrected (conclusions are not affected). v3: Accepted by MNRA
Cosmological constraints on holographic dark energy models under the energy conditions
We study the holographic and agegraphic dark energy models without
interaction using the latest observational Hubble parameter data (OHD), the
Union2.1 compilation of type Ia supernovae (SNIa), and the energy conditions.
Scenarios of dark energy are distinguished by the cut-off of cosmic age,
conformal time, and event horizon. The best-fit value of matter density for the
three scenarios almost steadily located at by the joint
constraint. For the agegraphic models, they can be recovered to the standard
cosmological model when the constant which presents the fraction of dark
energy approaches to infinity. Absence of upper limit of by the joint
constraint demonstrates the recovery possibility. Using the fitted result, we
also reconstruct the current equation of state of dark energy at different
scenarios, respectively. Employing the model criteria
, we find that conformal time model is the worst,
but they can not be distinguished clearly. Comparing with the observational
constraints, we find that SEC is fulfilled at redshift with confidence level. We also find that NEC gives a meaningful
constraint for the event horizon cut-off model, especially compared with OHD
only. We note that the energy condition maybe could play an important role in
the interacting models because of different degeneracy between and
constant .Comment: 8 pages, 4 figures, accepted for publication in PR
Joint Communication and Computational Resource Allocation for QoE-driven Point Cloud Video Streaming
Point cloud video is the most popular representation of hologram, which is
the medium to precedent natural content in VR/AR/MR and is expected to be the
next generation video. Point cloud video system provides users immersive
viewing experience with six degrees of freedom and has wide applications in
many fields such as online education, entertainment. To further enhance these
applications, point cloud video streaming is in critical demand. The inherent
challenges lie in the large size by the necessity of recording the
three-dimensional coordinates besides color information, and the associated
high computation complexity of encoding. To this end, this paper proposes a
communication and computation resource allocation scheme for QoE-driven point
cloud video streaming. In particular, we maximize system resource utilization
by selecting different quantities, transmission forms and quality level tiles
to maximize the quality of experience. Extensive simulations are conducted and
the simulation results show the superior performance over the existing scheme
Analytical solutions to the spin-1 Bose-Einstein condensates
We analytically solve the one-dimensional coupled Gross-Pitaevskii equations
which govern the motion of F=1 spinor Bose-Einstein condensates. The nonlinear
density-density interactions are decoupled by making use of the unique
properties of the Jacobian elliptical functions. Several types of complex
stationary solutions are deduced. Furthermore, exact non-stationary solutions
to the time-dependent Gross-Pitaevskii equations are constructed by making use
of the spin-rotational symmetry of the Hamiltonian. The spin-polarizations
exhibit kinked configurations. Our method is applicable to other coupled
nonlinear systems.Comment: 12 figure
Incomplete nonextensive statistics and the zeroth law of thermodynamics
National Natural Science Foundation of China [11005041]; Natural Science Foundation of Fujian Province, China [2010J05007]; Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China [2010-1561]; Basic Science Research Foundation, China [JB-SJ1005]; Science Research Fund of Huaqiao University, China [11BS207]On the basis of the entropy of incomplete statistics (IS) and the joint probability factorization condition, two controversial problems existing in IS are investigated: one is what expression of the internal energy is reasonable for a composite system and the other is whether the traditional zeroth law of thermodynamics is suitable for IS. Some new equivalent expressions of the internal energy of a composite system are derived through accurate mathematical calculation. Moreover, a self-consistent calculation is used to expound that the zeroth law of thermodynamics is also suitable for IS, but it cannot be proven theoretically. Finally, it is pointed out that the generalized zeroth law of thermodynamics for incomplete nonextensive statistics is unnecessary and the nonextensive assumptions for the composite internal energy will lead to mathematical contradiction
GW25-e1160 Detection of right-to-left shunt in secundum atrial septal defect without severe pulmonary hypertension by saline contrast
Arabidopsis NMD3 Is Required for Nuclear Export of 60S Ribosomal Subunits and Affects Secondary Cell Wall Thickening
NMD3 is required for nuclear export of the 60S ribosomal subunit in yeast and vertebrate cells, but no corresponding function of NMD3 has been reported in plants. Here we report that Arabidopsis thaliana NMD3 (AtNMD3) showed a similar function in the nuclear export of the 60S ribosomal subunit. Interference with AtNMD3 function by overexpressing a truncated dominant negative form of the protein lacking the nuclear export signal sequence caused retainment of the 60S ribosomal subunits in the nuclei. More interestingly, the transgenic Arabidopsis with dominant negative interference of AtNMD3 function showed a striking failure of secondary cell wall thickening, consistent with the altered expression of related genes and composition of cell wall components. Observation of a significant decrease of rough endoplasmic reticulum (RER) in the differentiating interfascicular fiber cells of the transgenic plant stems suggested a link between the defective nuclear export of 60S ribosomal subunits and the abnormal formation of the secondary cell wall. These findings not only clarified the evolutionary conservation of NMD3 functions in the nuclear export of 60S ribosomal subunits in yeast, animals and plants, but also revealed a new facet of the regulatory mechanism underlying secondary cell wall thickening in Arabidopsis. This new facet is that the nuclear export of 60S ribosomal subunits and the formation of RER may play regulatory roles in coordinating protein synthesis in cytoplasm and transcription in nuclei
Anti-cancer treatment within two weeks serves as a risk factor for clinical outcomes among cancer patients with COVID-19
BackgroundThe coronavirus disease 2019 (COVID-19) pandemic has resulted in infections among patients with cancer. Our study aimed to investigate the potential adverse impact of anti-cancer treatments within 2 weeks of COVID-19 infection on clinical outcomes in patients with cancer.MethodsThis retrospective cohort study analyzed 70 cancer patients with COVID-19 infection from the First Hospital of Jilin University in Changchun City, Jilin Province, between March and June 2022. Data on demographic characteristics, vaccination status, COVID-19 clinical classification, symptoms, complications, tumor-related characteristics, laboratory examinations and medical interventions were extracted from electronic medical record. The primary outcome of our study was Intensive Care Unit (ICU) admission. Logistic regression model was performed to investigate the association between anti-cancer treatments within 2 weeks after COVID-19 infection and the risk of ICU admission.ResultsOf the 70 patients enrolled in this study, 37 received anti-cancer treatments within 2 weeks after COVID-19 infection. Patients receiving anti-cancer treatment were more likely to experience non-mild COVID-19, require oxygen therapy, develop acute respiratory distress syndrome (ARDS) and exhibit elevated inflammatory levels. The risk of ICU admission (P<0.001) and 30-day mortality after reverse transcriptase polymerase chain reaction (RT-PCR) negative conversion (P=0.007) was significantly higher in patients receiving anti-cancer treatments. In multivariate Logistic regression analysis, non-mild classification of COVID-19, anti-cancer treatments within 2 weeks and ECOG > 1were all independently associated with ICU admission after adjusting for confounder factors. The risk of ICU admission rose to 43.63 times (95% confidence interval=1.31β1452.94, P=0.035) in patients receiving anti-cancer treatments within 2 weeks.ConclusionAnti-cancer treatments within 2 weeks of COVID-19 infection increase the risk of ICU admission and 30-day mortality after RT-PCR negative conversion in patients with cancer. It may be recommended to postpone cancer-related treatments for more than 2 weeks in cancer patients with COVID-19 infection
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