The Cross-Section of Volatility and Expected Returns

We examine the pricing of aggregate volatility risk in the cross-section of stock returns. Consistent with theory, we find that stocks with high sensitivities to innovations in aggregate volatility have low average returns. In addition, we find that stocks with high idiosyncratic volatility relative to the Fama and French (1993) model have abysmally low average returns. This phenomenon cannot be explained by exposure to aggregate volatility risk. Size, book-to-market, momentum, and liquidity effects cannot account for either the low average returns earned by stocks with high exposure to systematic volatility risk or for the low average returns of stocks with high idiosyncratic volatility.

Hypoglycemic, hypolipidemic and antioxidant effects of iridoid glycosides extracted from: Corni fructus: Possible involvement of the PI3K-Akt/PKB signaling pathway

Iridoid glycosides (CIG) are the major component of Corni fructus. In this work, we researched the antioxidative, hypoglycemic and lowering blood lipids effects of CIG on diabetic mice induced by a high-fat diet (HFD) and streptozotocin (STZ). Furthermore, to investigate the molecular mechanism of action, the phosphorylation and protein expression of phosphoinositide 3-kinase (PI3K) and its downstream proteins, such as insulin receptor (INSR), protein kinase B (Akt/PKB) and glucose transporter 4 (GLUT4) have been detected. The results showed that CIG significantly improved oral glucose tolerance in diabetic mice. Biochemical indices also revealed that CIG had a positive effect on lipid metabolism and oxidative stress. In addition, CIG can significantly enhance the expression level of the PI3K-Akt/PKB pathway related proteins in skeletal muscle, which is the key pathway of insulin metabolism. These findings show that CIG can improve the hyperglycemia and hyperlipidemia of HFD-STZ-induced diabetic mice through the PI3K-Akt/PKB signaling pathway, and CIG might be a potential medicine or functional food for type 2 diabetes mellitus remedies. © 2018 The Royal Society of Chemistry

Intrinsic Appearance Decomposition Using Point Cloud Representation

Intrinsic decomposition is to infer the albedo and shading from the image. Since it is a heavily ill-posed problem, previous methods rely on prior assumptions from 2D images, however, the exploration of the data representation itself is limited. The point cloud is known as a rich format of scene representation, which naturally aligns the geometric information and the color information of an image. Our proposed method, Point Intrinsic Net, in short, PoInt-Net, jointly predicts the albedo, light source direction, and shading, using point cloud representation. Experiments reveal the benefits of PoInt-Net, in terms of accuracy, it outperforms 2D representation approaches on multiple metrics across datasets; in terms of efficiency, it trains on small-scale point clouds and performs stably on any-scale point clouds; in terms of robustness, it only trains on single object level dataset, and demonstrates reasonable generalization ability for unseen objects and scenes.Comment: 14 pages, 14 figure

Evaluation of the safety of retroperitoneal laparoscopic partial nephrectomy by investigating the perioperative indicators

BackgroundIn recent years, open nephron sparing partial nephrectomy (OPN) has been gradually applied and generally accepted. Recent statistical data show that PN not only can safely and effectively preserve the functional nephron, but also has fewer complications, low local recurrence rate and no significant difference in long-term survival rate compared with nephrectomy/radical nephrectomy, which has gradually become a routine treatment for small renal cell carcinoma. Therefore, how to maximize the protection of postoperative residual renal function (RRF) and reduce the risk of CKD while achieving the ideal local and overall tumor control effect is the key to the treatment of renal cancer, and is also the focus of attention of urologists and nephrologists.ObjectiveTo evaluate the safety of retroperitoneal laparoscopic partial nephrectomy (RLPN) by investigating the perioperative indicators and postoperative follow-up.MethodsA total of 40 hospitalized patients in our hospital from December 2019 to December 2021 were selected and followed up for a long time. Patients with renal tumors less than 4cm in diameter and exogeneous or partial exogeneity were randomly divided into 2 groups. Patients in retroperitoneal laparoscopic group (n = 20) were treated with nephron sparing partial nephrectomy (0.5-1cm). Twenty patients underwent retroperitoneal laparoscopic radical nephrectomy (LRN).The time of removal of drainage tube, drainage volume, time of feeding activity and postoperative hospital stay were recorded, and the safety of the operation was evaluated.Resultsnephron sparing partial nephrectomy is suitable for patients with localized renal carcinoma or benign tumor <4cm. RLPN can be applied to all indications of open nephron sparing partial nephrectomy (OPN), with good safety, and can preserve residual renal function to the greatest extent. The operative vascular occlusion time was controlled within 40 minutes, and the use of renal function protection measures during the operation was safe and controllable in reducing the prevention of warm ischemic kidney damage, with good safety. The renal tumor capsule with 0.5cm~1cm margin was complete by postoperative pathology. In the process of tumor resection and suture collection system in the RLPN group, we improved the previous operation of “resection before hemostasis” to “resection while hemostasis” and “knot-free suture” technology, which saved the operation time of intracavity suture knotting. Reduced cortical tear caused by vertical pull during knot tying. The combined effect of biological clip and hemostatic gauze can stimulate the granulation proliferation of renal cortical wound and accelerate the repair. With the combination of knot-free suture and renal segment vascular occlusion, hot ischemic kidney damage is reduced. In the RLPN group, there were no complications of urinary fistula and bleeding, and no abnormal changes in renal function during follow-up. The safety of RLPN group is worthy of affirmation.ConclusionThe perioperative safety and short-term postoperative renal function recovery of RLPN are good, and the overall safety of this operation is worthy of affirmation

STAR-RIS Assisted Covert Communications in NOMA Systems

Covert communications assisted by simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) in non-orthogonal multiple access (NOMA) systems have been explored in this paper. In particular, the access point (AP) transmitter adopts NOMA to serve a downlink covert user and a public user. The minimum detection error probability (DEP) at the warden is derived considering the uncertainty of its background noise, which is used as a covertness constraint. We aim at maximizing the covert rate of the system by jointly optimizing APs transmit power and passive beamforming of STAR-RIS, under the covertness and quality of service (QoS) constraints. An iterative algorithm is proposed to effectively solve the non-convex optimization problem. Simulation results show that the proposed scheme significantly outperforms the conventional RIS-based scheme in ensuring system covert performance.Comment: arXiv admin note: text overlap with arXiv:2305.04930, arXiv:2305.0399

WS2 as a saturable absorber for ultrafast photonic applications of mode-locked and Q-switched lasers

Two-dimensional (2D) nanomaterials, especially the transition metal sulfide semiconductors, have drawn great interests due to their potential applications in viable photonic and optoelectronic devices, such as saturable absorbers (SAs) and optical switches, etc. In this work, tungsten disulfide (WS2) based SA for ultrafast photonic applications was demonstrated. WS2 nanosheets were prepared using liquid-phase exfoliation method and embedded in polyvinyl alcohol (PVA) thin film for the practical usage. Saturable absorption was observed in the WS2-PVA SA at the telecommunication waveband near 1550 nm. By incorporating WS2-PVA SA into a fiber laser cavity, both stable mode locking operation and Q-switching operation were achieved. In the mode locking operation, the laser obtained femtosecond output pulse width and high spectral purity in the radio frequency spectrum. In the Q-switching operation, the laser had tunable repetition rate and output pulse energy of a few tens of nano joule. Our findings suggest that few-layer WS2 nanosheets embedded in PVA thin film are promising nonlinear optical materials for ultrafast photonic applications as a mode locker or Q-switcher.Comment: 15 pages, 6 figure

High Idiosyncratic Volatility and Low Returns: International and Further U.S. Evidence

Stocks with recent past high idiosyncratic volatility have low future average returns around the world. Across 23 developed markets, the difference in average returns between the extreme quintile portfolios sorted on idiosyncratic volatility is -1.31% per month, after controlling for world market, size, and value factors. The effect is individually significant in each G7 country. In the U.S., we rule out explanations based on trading frictions, information dissemination, and higher moments. There is strong comovement in the low returns to high idiosyncratic volatility stocks across countries, suggesting that broad, not easily diversifiable, factors may lie behind this phenomenon.

Hemoglobin levels and anemia evaluation during pregnancy in the highlands of Tibet: a hospital-based study.

BACKGROUND: Anemia is regarded as a major risk factor for unfavorable pregnancy outcomes, but there have been no previous studies describing the pattern of hemoglobin concentration during pregnancy in Tibet and the relationship between altitude and Hb concentration in the pregnant women living in Tibet still has not been clearly established. The main objectives of this study were to study the hemoglobin levels and prevalence of anemia among pregnant women living in the highlands of Tibet and to evaluate potential associations of hemoglobin and anemia with women's characteristics. METHODS: The hospital-based study was conducted in 380 pregnant women. Their blood samples were tested and related sociodemographic information was collected. Multiple linear regression model and multiple logistic regression model were used to assess the association of pregnant women's characteristics with hemoglobin level and the occurrence of anemia. Centers for Disease Control (CDC), Dirren et al. and Dallman et al. methods were used to adjust the hemoglobin measurements based on altitude for estimating the prevalence of anemia. RESULTS: The mean hemoglobin concentration was 127.6 g/L (range: 55.0-190.0 g/L). Prevalence rate of anemia in this study was 70.0%, 77.9% and 41.3%, respectively for three altitude-correction methods for hemoglobin (CDC method, Dirren et al. method, and Dallman et al. method). Gestational age, ethnicity, residence and income were significantly associated with the hemoglobin concentration and prevalence of anemia in the study population. Specially, the hemoglobin concentration of pregnant women decreased with increase in gestational age. CONCLUSION: The hemoglobin level was low and prevalence rate of anemia was high among pregnant women in Lhasa, Tibet. Gestational age, ethnicity, residence and income were found to be significantly associated with the hemoglobin level and the occurrence of anemia in the study population