Shear Viscosity of Uniform Fermi Gases with Population Imbalance

The shear viscosity plays an important role in studies of transport phenomena in ultracold Fermi gases and serves as a diagnostic of various microscopic theories. Due to the complicated phase structures of population-imbalanced Fermi gases, past works mainly focus on unpolarized Fermi gases. Here we investigate the shear viscosity of homogeneous, population-imbalanced Fermi gases with tunable attractive interactions at finite temperatures by using a pairing fluctuation theory for thermodynamical quantities and a gauge-invariant linear response theory for transport coefficients. In the unitary and BEC regimes, the shear viscosity increases with the polarization because the excess majority fermions cause gapless excitations acting like a normal fluid. In the weak BEC regime the excess fermions also suppress the noncondensed pairs at low polarization, and we found a minimum in the ratio of shear viscosity and relaxation time. To help constrain the relaxation time from linear response theory, we derive an exact relation connecting some thermodynamic quantities and transport coefficients at the mean-field level for unitary Fermi superfluids with population imbalance. An approximate relation beyond mean-field theory is proposed and only exhibits mild deviations from numerical results.Comment: 11 pages, 4 figure

Reduction of graphene oxide by an in-situ photoelectrochemical method in a dye-sensitized solar cell assembly

Reduction of graphene oxide [GO] has been achieved by an in-situ photoelectrochemical method in a dye-sensitized solar cell [DSSC] assembly, in which the semiconductor behavior of the reduced graphene oxide [RGO] is controllable. GO and RGO were characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, high-resolution transmission electron microscope, and Fourier-transform infrared spectroscopy. It was found that the GO film, which assembled in the DSSC assembly as the counter electrode, was partly reduced. An optimized photoelectrochemical assembly is promising for modulating the reduction degree of RGO and controlling the band structure of the resulting RGO. Moreover, this method appeared to be a green progress for the production of RGO electrodes

A potential explanation for the effect of carbon source on the characteristics of acetate-fed and glucose-fed aerobic granules

This paper proposes a new theory to account for the effect of carbon source on the characteristics of acetate-fed and glucose-fed aerobic granules. It is well known that reactor pH can vary in response to the oxidation of glucose or sodium acetate. As such, the effects associated with the carbon sources may be explained by the changed pH. The proposal was explored by experiments. Aerobic granules were cultivated in three identical sequencing batch reactors (SBRs, R1, R2 and R3), fed with sodium acetate, glucose, glucose and maintained pH at 4.5 - 5.5 (the variation of reactor pH in the oxidation of glucose), 4.5 - 5.5 and 7.5 - 8.5 (the variation of reactor pH in the oxidation of sodium acetate), respectively, and the effects of carbon source and reactor pH on the characteristics of aerobic granules were assessed. The results showed that the characteristics of aerobic granules, including microbial structure, mixed liquor suspended solids (MLSS), sludge volume index (SVI) and nitrification-denitrification, were strongly affected by reactor pH, but were independent with the carbon source supplied. These results fully supported the validity of the new theory. The theory suggests that the cultivation of aerobic granules with glucose or sodium acetate should take more attention to reactor pH rather than carbon source itself. The implications of this theory are discussed with regards to the other common carbon sources as well as better understanding of the mechanisms of aerobic granulation.Keywords: Acetate-fed granules, glucose-fed granules, reactor pH, carbon source, characteristicsAfrican Journal of Biotechnology Vol. 9(33), pp. 5357-5365, 16 August, 201

SAMIHS: Adaptation of Segment Anything Model for Intracranial Hemorrhage Segmentation

Segment Anything Model (SAM), a vision foundation model trained on large-scale annotations, has recently continued raising awareness within medical image segmentation. Despite the impressive capabilities of SAM on natural scenes, it struggles with performance decline when confronted with medical images, especially those involving blurry boundaries and highly irregular regions of low contrast. In this paper, a SAM-based parameter-efficient fine-tuning method, called SAMIHS, is proposed for intracranial hemorrhage segmentation, which is a crucial and challenging step in stroke diagnosis and surgical planning. Distinguished from previous SAM and SAM-based methods, SAMIHS incorporates parameter-refactoring adapters into SAM's image encoder and considers the efficient and flexible utilization of adapters' parameters. Additionally, we employ a combo loss that combines binary cross-entropy loss and boundary-sensitive loss to enhance SAMIHS's ability to recognize the boundary regions. Our experimental results on two public datasets demonstrate the effectiveness of our proposed method. Code is available at https://github.com/mileswyn/SAMIHS .Comment: 5 pages, 3 figures, 2 table

An ultra-luminous quasar at z=5.363 with a ten billion solar mass black hole and a Metal-Rich DLA at z~5

We report the discovery of an ultra-luminous quasar J030642.51+185315.8 (hereafter J0306+1853) at redshift 5.363, which hosts a super-massive black hole (SMBH) with $M_{BH} = (1.07 \pm 0.27) \times10^{10}~M_\odot$. With an absolute magnitude $M_{1450}=-28.92$ and bolometric luminosity $L_{bol}\sim3.4\times10^{14} L_{\odot}$, J0306+1853 is one of the most luminous objects in the early Universe. It is not likely to be a beamed source based on its small flux variability, low radio loudness and normal broad emission lines. In addition, a $z=4.986$ Damped Ly$\alpha$ system (DLA) with $\rm [M/H]=-1.3\pm0.1$, among the most metal rich DLAs at $z \gtrsim 5$, is detected in the absorption spectrum of this quasar. This ultra-luminous quasar puts strong constraint on the bright-end of quasar luminosity function and massive-end of black hole mass function. It will provide a unique laboratory to the study of BH growth and the co-evolution between BH and host galaxy with multi-wavelength follow-up observations. The future high resolution spectra will give more insights to the DLA and other absorption systems along the line-of-sight of J0306+1853.Comment: 5 pages, 3 figures, accepted for publication in ApJ

Non-linear carbon dioxide determination using infrared gas sensors and neural networks with Bayesian regularization

Carbon dioxide gas concentration determination using infrared gas sensors combined with Bayesian regularizing neural networks is presented in this work. Infrared sensor with a measuring range of 0~5% was used to measure carbon dioxide gas concentration within the range 0~15000 ppm. Neural networks were employed to fulfill the nonlinear output of the sensor. The Bayesian strategy was used to regularize the training of the back propagation neural network with a Levenberg-Marquardt (LM) algorithm. By Bayesian regularization (BR), the design of the network was adaptively achieved according to the complexity of the application. Levenberg-Marquardt algorithm under Bayesian regularization has better generalization capability, and is more stable than the classical method. The results showed that the Bayesian regulating neural network was a powerful tool for dealing with the infrared gas sensor which has a large non-linear measuring range and provide precise determination of carbon dioxide gas concentration. In this example, the optimal architecture of the network was one neuron in the input and output layer and two neurons in the hidden layer. The network model gave a relationship coefficient of 0.9996 between targets and outputs. The prediction recoveries were within 99.9~100.0%

Yangjing capsule attenuates cyclophosphamide-induced deficiency of testicular microcirculation in mice

Purpose: To explore the protective effects of Yangjing capsule (YC) on testicular microcirculation in a mouse model of deficiency of testicular microcirculation. Methods: Immunohistochemistry was applied to determine the effects of YC on microvascular density of mice. The protein level of CD34 and vascular endothelial growth factor A (VEGF A) was measured by western blot. The viability of Testicular cell line (TM4 cells) was examined by CCK-8 assay. Results: Histopathological changes demonstrated that CP-induced decrease of microvascular density of the mice was rescued by YC dose-dependently (p < 0.5). Western blot data showed that the protein levels of CD34 and VEGF A in CP group were significantly decreased, but dose-dependently increased by YC, respectively, following co-administration of CP + YC, compared with those in CP group (p < 0.5). The results from CCK-8 assay showed that the cell viability of TM4 cells increased with the amount of YC administered, and that high concentrations of YC (0.1 and 1 mg/mL) showed significant effects (p < 0.5). Moreover, YC showed little effect on VEGF A mRNA and protein expression in TM4 cells. Conclusion: YC may be considered an alternative therapeutic agent for the management of testicular microcirculation disease. However, further studies are required to ascertain this. Keywords: Yangjing Capsule, Testicular microcirculation, Cyclophosphamide, Vascular endothelial growth factor

An analytic relation for the thickness of accretion flows

We take the vertical distribution of the radial and azimuthal velocity into account in spherical coordinates, and find that the analytic relation c_{s0}/(v_K \Theta) = [(\gamma -1)/(2\gamma)]^{1/2} is valid for both geometrically thin and thick accretion flows, where c_{s0} is the sound speed on the equatorial plane, v_K is the Keplerian velocity, \Theta is the half-opening angle of the flow, and \gamma is the adiabatic index.Comment: 4 pages, 2 figures, accepted by Science in China Series

Upwelling velocity and ventilation in the western South China Sea deduced from CFC-12 and SF6 observations

This study presents observations of the transient tracers CFC-12 and SF6 in the western South China Sea during the fall of 2015. A CFC-12 maximum was discovered in the western South China Sea at the subsurface layer (150–200 m), which could be traced back to the North Pacific Tropical Water. The transit time distribution approach was used to estimate the ventilation time in this area. The constrained Δ /Γ ratio of 0.5 was obtained using CFC-12/SF6 tracer pair. This ratio is lower than the empirical unit ratio of one as used for previous estimates. Waters in the northern region of the western South China Sea appear younger than waters in the southern region. The water mass corresponding to the salinity minimum has a mean age of ∼67 ± 16 years along the 15º N line (marked by the red dashed rectangle in Fig. 1), which increases to ∼76 ± 18 years along the 10º N line (blue dashed rectangle, Fig. 1). The higher mean ages indicate that the intermediate water was ventilated from the North Pacific, which is far distant from the South China Sea. The column inventory of Cant is ∼31.3 mol C m–2. Upwelling velocities of up to ∼55 × 10–5 m s–1 was computed using the tracer data, indicating that tracer-free water as yet not influenced by human perturbation could be carried to the upper layer by upwelling. Using the transit time distribution derived mean age with transient tracers provides a possible way to determine the ventilation time scale for the study area