Implication of nano-Hertz stochastic gravitational wave on dynamical dark matter through a first-order phase transition

For the first time, the expected stochastic gravitational wave background is probably discovered after observing the Hellings Downs correlation curve by several pulsar timing array (PTA) collaborations around the globe including NANOGrav, European PTA, Parkes PTA, and Chinese PTA. These new observations can help to explore the dark matter formation mechanisms in the early universe. We study the implication of those results on the dynamical dark matter formation mechanisms through first-order phase transition in the early universe. Both the Q-ball dark matter and super-cool dark matter are investigated in the strong super-cooling phase transition which are consistent with the observed stochastic gravitational wave background.Comment: 22 pages, 6 figures, 1 table; comments are welcom

CO2 dissociation activated through electron attachment on reduced rutile TiO2(110)-1x1 surface

Converting CO$_2$ to useful compounds through the solar photocatalytic reduction has been one of the most promising strategies for artificial carbon recycling. The highly relevant photocatalytic substrate for CO$_2$ conversion has been the popular TiO$_2$ surfaces. However, the lack of accurate fundamental parameters that determine the CO$_2$ reduction on TiO$_2$ has limited our ability to control these complicated photocatalysis processes. We have systematically studied the reduction of CO2 at specific sites of the rutile TiO$_2$(110)-1x1 surface using scanning tunneling microscopy at 80 K. The dissociation of CO2 molecules is found to be activated by one electron attachment process and its energy threshold, corresponding to the CO$_2^{\dot-}$/CO$_2$ redox potential, is unambiguously determined to be 2.3 eV higher than the onset of the TiO$_2$ conduction band. The dissociation rate as a function of electron injection energy is also provided. Such information can be used as practical guidelines for the design of effective catalysts for CO$_2$ photoreduction

Online Static Voltage Stability Monitoring for Power Systems Using PMU Data

A new online static voltage stability monitoring method for power systems is proposed by using phasor measurement unit (PMU) data in this paper. This approach uses the real-time power, voltage, and phase angle data collected by the PMU to estimate the power flow Jacobian matrix of the system, and then the static voltage stability is monitored via the minimum singular values (MSVs) of the power flow Jacobian matrix. The novelty of the approach lies in the fact that it only utilizes PMU data for implementing online monitoring of the power system static voltage stability, independent of the physical model and its parameters. The application results on the IEEE 57-bus test system verify the effectiveness of the proposed approach

Random Vector Functional Link Network Optimized by Jaya Algorithm for Transient Stability Assessment of Power Systems

A novel transient stability assessment (TSA) approach using random vector functional link (RVFL) network optimized by Jaya algorithm, called Jaya-RVFL, is proposed for power systems in this paper. First, by extracting system-level features from phasor measurement unit (PMU) measurements as predictors, an RVFL-based TSA model is proposed. In order to improve the performance of RVFL classifiers, a quantile scaling approach is utilized to optimize the randomization range of input weights via the Jaya algorithm. The simulation results on IEEE 39-bus system and a real-world power system show that the presented method outperforms other popular methods comprising multilayer perception, probabilistic neural network, and support vector machine

Development and effectiveness of a mobile phone application conducting health behavioral intervention among men who have sex with men, a randomized controlled trial: study protocol

Abstract Background Behavioral intervention is a key approach to HIV prevention among men who have sex with men (MSM). Widespread use of mobile phones provide us with novel opportunities to decrease HIV infection and transmission of MSM. The objective of the study was to design and develop a mobile phone application (app) aims to conduct behavioral intervention to MSM and to evaluate the efficacy of the app-based intervention compared to usual care, to analyze cost-effectiveness and mechanism of the intervention. Methods This study involves 2 phases, phase 1 use qualitative method and phase 2 is a randomized controlled trial lasting for 18 months, they will be conducted in Chagnsha, Hunan Province, China. Phase 1 is to design and develop the app, procedures including retrieval of domestic apps related to prevention and treatment about HIV and sexually transmitted diseases (HIV/STDs), personal interviews with MSM about preferences and functional needs of the HIV prevention app, multidisciplinary experts focused group discussions of the app, software engineers’ development and users test of the app will be performed. In phase 2, we will recruit 800 MSM by cooperating with the local center of disease control and prevention and nongovernmental organizations, and divide them into intervention and control group evenly. Intervention group participants will receive app-based HIV prevention. Control group participants will be provided with usual care including HIV/STDs knowledge brochure and free voluntary counseling services. Data will be collected at baseline, 6, 12 and 18 months since subject’s participation. Effectiveness of the intervention includes HIV/STDs infection rates, adherence to regularly HIV testing, sexual risk behavior, consistent condom use and relative risk of HIV infection. Cost-effectiveness will be analyzed by decision-analytic modeling, and mechanism analysis of this app-based intervention will be performed by path analysis. Discussion This will be the first study of its kind in China to develop an app and implement app-based HIV prevention intervention among MSM. It is of great potential to determine whether app-based intervention is a cost-effective way to decrease HIV infection among MSM and explore intervention mechanism with an accurate method. Trial registration Chinese Clinical Trial Register ( ChiCTR-IOR-15006724 ). Registered 10 July 2015

Preparation of Monoclonal Antibody against Deoxynivalenol and Development of Immunoassays

Fusarium toxins are the largest group of mycotoxins, which contain more than 140 known secondary metabolites of fungi. Deoxynivalenol (DON) is one of the most important compounds of this class due to its high toxicity and its potential to harm mankind and animals and a widespread contaminant of agricultural commodities, such as wheat, corn, barley, oats, bread, and biscuits. Herein, a hybridoma cell 8G2 secreting mAb against DON was produced by fusing the splenocytes with a tumor cell line Sp2/0. The obtained mAb had a high affinity (2.39 × 109 L/mol) to DON. An indirect competitive Enzyme-Linked Immunosorbent Assay (ic-ELISA) showed that the linear range for DON detection was 3.125–25 μg/mL, and the minimum inhibitory concentration (IC50) was 18.125 μg/mL with a limit of detection (LOD) of 7.875 μg/mL. A colloidal gold nanoparticle (AuNP) with 20 nm in diameter was synthesized for on-site detection of DON within 10 min with vLOD of 20 μg/mL. To improve the limit of detection, the gold nanoflower (AuNF) with a larger size (75 nm) was used to develop the AuNF-based strip with vLOD of 6.67 μg/mL. Compared to the vLOD of a convectional AuNP-based strip, the AuNF-based strip was three times lower. Herein, three immunoassay methods (ic-ELISA and AuNP/AuNF-based strips) were successfully developed, and these methods could be applied for the DON detection in agricultural products

Impact of Mountain Reservoir Construction on Groundwater Level in Downstream Loess Areas in Guanzhong Basin, China

An accurate understanding of the relationship between reservoir construction and the dynamic change of groundwater level in downstream areas is of great significance for rational development and utilization of water resources. At present, the research on the interaction between surface water (SW) and groundwater (GW) mainly focuses on the interaction between river and GW. There are few studies on the impact of the reservoir construction on GW level in downstream loess irrigation area. Rainfall, evaporation and climate temperature have a great impact on W level, but the impact of reservoir construction on the GW level should not be ignored in the utilization of water resources. In this paper, a GW flow model under a natural boundary was established by numerical simulation. Taking Heihe Jinpen Reservoir in Heihe River watershed as the research object, the influence of the construction of a mountain reservoir on the dynamic change of GW level in the downstream loess region is studied. By comparing the GW level under the natural state without reservoir construction and the measured GW level after the reservoir was built, the variation of the GW depth in the loess area of the lower reaches in the Heihe River watershed is obtained. The results show that simulation accuracy of the interaction between SW and GW was reasonable; after the Heihe Jinpen Reservoir construction, the mean GW level decrease was about 6.05 m in the downstream loess irrigation area in Guanzhong Basin. It provides a method for the simulation and prediction of SW–GW conversion laws. This study is also of great significance to explore the change law of the water cycle and improve the utilization rate of water resources