Controlling electron motion with attosecond precision by shaped femtosecond intense laser pulse

We propose the scheme of temporal double-slit interferometer to precisely measure the electric field of shaped intense femtosecond laser pulse directly, and apply it to control the electron tunneling wave packets in attosecond precision. By manipulating the spectra phase of the input femtosecond pulse in frequency domain, one single pulse is split into two sub-pulses whose waveform can be precisely controlled by adjusting the spectra phase. When the shaped pulse interacts with atoms, the two sub-pulses are analogous to the Young's double-slit in time domain. The interference pattern in the photoelectron momentum distribution can be used to precisely retrieve the peak electric field and the time delay between two sub-pulses. Based on the precise characterization of the shaped pulse, we demonstrate that the sub-cycle dynamics of electron can be controlled with attosecond precision. The above scheme is proved to be feasible by both quantum-trajectory Monte Carlo simulations and numerical solutions of three-dimensional time-dependent Schr\"{o}dinger equation.Comment: 10 pages,4 figure

Out of the Closet, Into the Clinic: Opportunities for Expanding Men Who Have Sex With Men-Competent Services in China.

BACKGROUND: Despite the high human immunodeficiency virus (HIV) burden among men who have sex with men (MSM), there is little research on health services provided to MSM in China and other low- and middle-income countries. Discrimination and inadequate services may discourage MSM from seeking health care services. This study examined essential services provided to MSM and health care discrimination among MSM in China. METHODS: A nationwide cross-sectional online survey was conducted among MSM who saw a physician in the last 24 months in China. The survey included items on sociodemographic information, HIV testing, experiences from the last physician encounter, and history of perceived health care discrimination. We defined MSM-competent physicians as physicians who asked their patient about having sex with other men, asked about anal sex, and either asked about or recommended HIV testing at the most recent visit. RESULTS: Among the 503 participants, 35.0% (176/503) saw an MSM-competent physician. In multivariate analyses, respondents who saw an MSM-competent physician were more likely to be younger (adjusted odds ratio [AOR], 0.87; 95% confidence interval [CI], 0.81-0.94), have a primary care physician (AOR, 3.24; 95% CI, 1.85-5.67), and be living with HIV (AOR, 2.01; 95% CI, 1.13-3.56). 61.2% (308/503) of MSM had ever experienced health care discrimination. CONCLUSIONS: Our data suggest that there is variability in the extent to which physicians are meeting the needs of MSM in China. There is an urgent need to evaluate and expand MSM-competent services in China

The interaction between HIV testing social norms and self-efficacy on HIV testing among Chinese men who have sex with men: results from an online cross-sectional study.

BACKGROUND: Increasing human immunodeficiency virus (HIV) testing is critical for HIV control. This study aimed to evaluate the interaction between social norms and self-efficacy on HIV testing among Chinese men who have sex with men (MSM). METHODS: We conducted an online survey in eight Chinese cities in Shandong and Guangdong Provinces in July 2016. We included participants who were born as a male, at least 16 years old, currently living in one of the designated cities, and had ever engaged in anal sex with a man. We collected information regarding socio-demographics, high-risk behaviors, and history of HIV and other STI testing. We coded sensitivity to social norms using six items asking participants about their perceived social norm regarding HIV testing. We coded HIV testing self-efficacy using a separate six-item scale. We interpreted higher mean scores as higher sensitivity to social norms and higher self-efficacy, respectively. We conducted logistic regressions to evaluate the interaction between self-efficacy and social norms on HIV testing. RESULTS: A total of 2105 men completed the survey. The mean age of the participants was 25.97 ± 6.42 years. Over four-fifths (85.9%) of participants were unmarried, 22.7% were students, and 64.6% at least had a college degree. 62.5 and 32.6% of participants ever and tested HIV in the last three months, respectively. With respect to uptake of HIV testing in the last three months, the adjusted odds ratio was 1.01(95% CI: 0.96-1.06) for higher sensitivity to social norms and 1.09 (95% CI: 1.05-1.14) for higher self-efficacy, with an interaction effect of 1.02 (95% CI: 1.01-1.03), respectively. With respect to uptake of lifetime HIV testing, the adjusted odds ratio was 1.03(95% CI: 0.99-1.07) for higher sensitivity to social norms and 1.15 (95% CI: 1.11-1.19) for higher self-efficacy, with an interaction effect of 1.02 (95% CI: 1.01-1.04), respectively. CONCLUSIONS: Our survey demonstrated that there is a significant association between the uptake of HIV testing with sensitivity to the social norm, higher self-efficacy, as well as the interaction between them. Tailored studies for improving HIV testing among MSM in China can combine these two interventions together

The interaction between HIV testing social norms and self-efficacy on HIV testing among Chinese men who have sex with men: results from an online cross-sectional study

Abstract Background Increasing human immunodeficiency virus (HIV) testing is critical for HIV control. This study aimed to evaluate the interaction between social norms and self-efficacy on HIV testing among Chinese men who have sex with men (MSM). Methods We conducted an online survey in eight Chinese cities in Shandong and Guangdong Provinces in July 2016. We included participants who were born as a male, at least 16 years old, currently living in one of the designated cities, and had ever engaged in anal sex with a man. We collected information regarding socio-demographics, high-risk behaviors, and history of HIV and other STI testing. We coded sensitivity to social norms using six items asking participants about their perceived social norm regarding HIV testing. We coded HIV testing self-efficacy using a separate six-item scale. We interpreted higher mean scores as higher sensitivity to social norms and higher self-efficacy, respectively. We conducted logistic regressions to evaluate the interaction between self-efficacy and social norms on HIV testing. Results A total of 2105 men completed the survey. The mean age of the participants was 25.97 ± 6.42 years. Over four-fifths (85.9%) of participants were unmarried, 22.7% were students, and 64.6% at least had a college degree. 62.5 and 32.6% of participants ever and tested HIV in the last three months, respectively. With respect to uptake of HIV testing in the last three months, the adjusted odds ratio was 1.01(95% CI: 0.96–1.06) for higher sensitivity to social norms and 1.09 (95% CI: 1.05–1.14) for higher self-efficacy, with an interaction effect of 1.02 (95% CI: 1.01–1.03), respectively. With respect to uptake of lifetime HIV testing, the adjusted odds ratio was 1.03(95% CI: 0.99–1.07) for higher sensitivity to social norms and 1.15 (95% CI: 1.11–1.19) for higher self-efficacy, with an interaction effect of 1.02 (95% CI: 1.01–1.04), respectively. Conclusions Our survey demonstrated that there is a significant association between the uptake of HIV testing with sensitivity to the social norm, higher self-efficacy, as well as the interaction between them. Tailored studies for improving HIV testing among MSM in China can combine these two interventions together

Large-scale features and evaluation of the PMIP4-CMIP6 midHolocene simulations

The mid-Holocene (6,000 years ago) is a standard experiment for the evaluation of the simulated response of global climate models using paleoclimate reconstructions. The latest mid-Holocene simulations are a contribution by the Palaeoclimate Model Intercomparison Project (PMIP4) to the current phase of the Coupled Model Intercomparison Project (CMIP6). Here we provide an initial analysis and evaluation of the results of the experiment for the mid-Holocene. We show that state-of-the-art models produce climate changes that are broadly consistent with theory and observations, including increased summer warming of the northern hemisphere and associated shifts in tropical rainfall. Many features of the PMIP4-CMIP6 simulations were present in the previous generation (PMIP3-CMIP5) of simulations. The PMIP4-CMIP6 ensemble for the mid-Holocene has a global mean temperature change of -0.3 K, which is -0.2 K cooler that the PMIP3-CMIP5 simulations predominantly as a result of the prescription of realistic greenhouse gas concentrations in PMIP4-CMIP6. Neither this difference nor the improvement in model complexity and resolution seems to improve the realism of the simulations. Biases in the magnitude and the sign of regional responses identified in PMIP3-CMIP5, such as the amplification of the northern African monsoon, precipitation changes over Europe and simulated aridity in mid-Eurasia, are still present in the PMIP4-CMIP6 simulations. Despite these issues, PMIP4-CMIP6 and the mid-Holocene provide an opportunity both for quantitative evaluation and derivation of emergent constraints on climate sensitivity and feedback strength

Large-scale features of Last Interglacial climate: results from evaluating the lig127k simulations for the Coupled Model Intercomparison Project (CMIP6)–Paleoclimate Modeling Intercomparison Project (PMIP4)

The modeling of paleoclimate, using physically based tools, is increasingly seen as a strong out-of-sample test of the models that are used for the projection of future climate changes. New to the Coupled Model Intercomparison Project (CMIP6) is the Tier 1 Last Interglacial experiment for 127 000 years ago (lig127k), designed to address the climate responses to stronger orbital forcing than the midHolocene experiment, using the same state-of-the-art models as for the future and following a common experimental protocol. Here we present a first analysis of a multi-model ensemble of 17 climate models, all of which have completed the CMIP6 DECK (Diagnostic, Evaluation and Characterization of Klima) experiments. The equilibrium climate sensitivity (ECS) of these models varies from 1.8 to 5.6 ∘C. The seasonal character of the insolation anomalies results in strong summer warming over the Northern Hemisphere continents in the lig127k ensemble as compared to the CMIP6 piControl and much-reduced minimum sea ice in the Arctic. The multi-model results indicate enhanced summer monsoonal precipitation in the Northern Hemisphere and reductions in the Southern Hemisphere. These responses are greater in the lig127k than the CMIP6 midHolocene simulations as expected from the larger insolation anomalies at 127 than 6 ka. New synthesis for surface temperature and precipitation, targeted for 127 ka, have been developed for comparison to the multi-model ensemble. The lig127k model ensemble and data reconstructions are in good agreement for summer temperature anomalies over Canada, Scandinavia, and the North Atlantic and for precipitation over the Northern Hemisphere continents. The model–data comparisons and mismatches point to further study of the sensitivity of the simulations to uncertainties in the boundary conditions and of the uncertainties and sparse coverage in current proxy reconstructions. The CMIP6–Paleoclimate Modeling Intercomparison Project (PMIP4) lig127k simulations, in combination with the proxy record, improve our confidence in future projections of monsoons, surface temperature, and Arctic sea ice, thus providing a key target for model evaluation and optimization

Fragility Analysis of Wind-Induced Collapse of a Transmission Tower Considering Corrosion

To investigate the variation law of the wind-resistant performance of transmission towers during their operation, this paper proposes an evaluation method for the wind resistance of the transmission tower considering corrosion, and a 220-kV transmission tower is analyzed as an example. Considering the uncertainty of the material and geometric parameters, the wind-induced collapse of the transmission tower was analyzed, and the collapse wind speeds were obtained via pushover and incremental dynamic analyses. In addition, the sensitivity of the transmission tower to various parameters was analyzed. Based on the existing meteorological and corrosion data, corrosion prediction models were established using a back-propagation (BP) artificial neural network, and the mean relative error between the predicted and measured values of the test samples was 8.91%. On this basis, the corrosion depth of the tower members in the four regions was predicted, and the fragility of the transmission tower was analyzed considering the effects of corrosion and strong winds. The results show that the collapse wind speed of the transmission tower is most significantly affected by the thickness of the angle steel, followed by the elastic modulus and yield strength, and is less affected by the width of the angle steel. When the exposure time was 25 years, the wind-resistant performance of transmission towers in regions with severe acid rain and coastal industrial regions decreased by 10% to 20%. With an increase in exposure time, the failure mode of the transmission tower tended to be brittle failure

A Legged Small Celestial Body Landing Mechanism: Landing Simulation and Experimental Test

Landing mechanism tends to rebound and turn over, and the stability time is long when landing on the small celestial body. Its landing performance in different conditions is necessary to be evaluated to guide the landing. Here, landing performance evaluation is realized by simulation. Key factors affecting the landing performance including cardan element damping, foot anchors, retro-rocket thrust, landing slope angle, and landing attitude are analyzed. A microgravity platform is built to test the landing mechanism, and the consistency between the simulation and the experiment is compared. On the basis of simulation and experiment, some landing suggestions are proposed to improve the landing performance