NN interaction from chiral effective field theory and its application to neutron-antineutron oscillations

An N¯N potential is introduced which is derived within chiral effective field theory and fitted to up-to-date N¯N phase shifts and inelasticities, provided by a proper phase-shift analysis of available p¯p scattering data. As an application of this interaction neutron-antineutron oscillations in the deuteron are considered. In particular, results for the deuteron lifetime are presented, evaluated in terms of the free-space n−n¯ oscillation time, utilizing that N¯N potential together with an NN interaction likewise derived within chiral effective field theory.

The current state of the vitivinicultural sector in mainland China

China's vineyard surface area accounts for the second place in the world, its grape production the first place, and its wine consumption and imports the fifth place. The vitivinicultural sector is playing an increasingly important role in the world. At the same time, vitivinicultural sector has also played an important role in poverty reduction in rural areas of China.Based on the background of the world vitivinicultural sector, it is of great significance to analyze the characteristics of China's domestic vitivinicultural sector, especially the situation of the primary, secondary and tertiary industries, to help China continue to reduce poverty in the countryside, optimize the industrial structure, and promote the integration of the three industries. At the same time, it also provides a reference for the consumption and trade of grape products between China and the world. This paper collected the authoritative statistical data of vitivinicultural sector in the world and China for the past two decades, including global national data and China’s provincial data, and analyzed the development trend of grape industries in China from the perspectives of vineyard surface area, grape production, grape use, wine production, consumption and trade in an international context. For the first time, China’s POI information of grape-related enterprises in Baidu online map was retrieved, and the spatial and temporal distribution characteristics of domestic grape industries were analyzed by using ArcGIS software. It includes the comparative analysis of grape surface area and production in different provinces, the development analysis of grape-related primary, secondary and tertiary industries, the trend analysis of grape cultivation in different provinces, and the shift analysis of industrial spatial gravity center. The result not only shows the changes of grape producing areas in China, but also tries to explore the distribution and integration of the three industries at the provincial scale in different parts of China. The future development of grape industry in 31 provinces in mainland China was predicted.

Influence of the Greater Protein Environment on the Electrostatic Potential in Metalloenzyme Active Sites: the Case of Formate Dehydrogenase

The Mo/W containing metalloenzyme formate dehydrogenase (FDH) is an efficient and selective natural catalyst which reversibly converts CO2 to formate under ambient conditions. A greater understanding of the role of the protein environment in determining the local properties of the FDH active site would enable rational bioinspired catalyst design. In this study, we investigate the impact of the greater protein environment on the electrostatic potential (ESP) of the active site. To model the enzyme environment, we used a combination of long-timescale classical molecular dynamics (MD) and multiscale quantum-mechanical/molecular-mechanical (QM/MM) simulations. We leverage the charge shift analysis method to systematically construct QM regions and analyze the electronic environment of the active site by evaluating the degree of charge transfer between the core active site and the protein environment. The contribution of the terminal chalcogen ligand to the ESP of the metal center is substantial and dependent on the chalcogen identity, with ESPs less negative and similar for Se and S terminal chalcogens than for O regardless of whether the Mo6+ or W6+ metal center is present. Our evaluation reveals that the orientation of the sidechains and ligand conformations will alter the relative trends in the ESP observed for a given metal center or terminal chalcogen, highlighting the importance of sampling dynamic fluctuations in the protein. Overall, our observations suggest that the terminal chalcogen ligand identity plays an important role in the enzymatic activity of FDH.

Study of Positron Impact Scattering from Methane and Silane Using an Analytically Obtained Static Potential with Correlation Polarization

A detailed study of positron impact elastic scattering from methane and silane is carried out using a model potential consisting of static and polarization potentials. The static potential for the molecular target is obtained analytically by using accurate Gaussian molecular wavefunctions. The molecular orbitals are expressed as a linear combination of Gaussian atomic orbitals. Along with the analytically obtained static potential, a correlation polarization potential is also added to construct the model potential. Utilizing the model potential, the Schrödinger equation is solved using the partial wave phase shift analysis method, and the scattering amplitude is obtained in terms of the phase shifts. Thereafter, the differential, integrated and total cross sections are calculated. These cross-section results are compared with the previously reported measurements and theoretical calculations.

Relative Contribution of Climate Change and Anthropogenic Activities to Streamflow Alterations in Illinois

Rainfed agricultural systems have become more vulnerable to climate change due to their significant dependence on natural precipitation. Drastic changes in precipitation, superimposed with anthropogenic activities, including land use land cover change, can modify the hydrologic response, especially in agricultural watersheds. In this study, Fisher Information and cumulative sum charts (CUMSUM) methods were applied to detect the hydrologic regime shifts in six watersheds in Illinois, USA. The regime shift analysis identified shifts in streamflow regime in three agricultural watersheds, mainly around the 1970s; whereas, no significant change in streamflow was observed for forest-dominated watersheds. Furthermore, the Budyko framework was used to determine the relative contribution in streamflow alterations (i.e., regime shifts in streamflow) for the agricultural watersheds, which evidenced significant shifts in streamflow. The Budyko analysis inferred that alterations in streamflow could be primarily attributed to anthropogenic activities with a comparatively lower contribution from climate in agricultural watersheds. The relative contribution from anthropogenic activities were 71.66%, 81.46%, and 74.04%; whereas, the relative contribution from climate were 28.34%, 18.54%, and 25.96% for the Sangamon, Vermillion, and Skillet agricultural watersheds, respectively. The techniques used and the results obtained from the study would be helpful for future research in assessing the vulnerability and impact of management practices in a highly managed agricultural watershed.

Aerosol Analysis Using Handheld Raman Spectrometer: On-site Quantification of Trace Crystalline Silica in Workplace Atmospheres

A method for aerosol chemical analysis using handheld Raman spectrometer has been developed and its application to measurement of crystalline silica concentration in workplace atmosphere is described. The approach involves collecting aerosol as a spot sample using a wearable optical aerosol monitor, followed by direct-on-filter quantitative analysis of the spot sample for crystalline silica using handheld Raman spectrometer. The filter cassette of a commercially available optical aerosol monitor (designed to collect aerosol for post-shift analysis) was modified to collect 1.5-mm-diameter spot sample, which provided adequate detection limits for short-term measurements over a few tens of minutes or hours. The method was calibrated using aerosolized α-quartz standard reference material in the laboratory. Two Raman spectrometers were evaluated, one a handheld unit (weighing less than 410 g) and the other a larger probe-based field-portable unit (weighing about 5 kg). The lowest limit of quantification for α-quartz of 16.6 μg m−3 was obtained using the handheld Raman unit at a sample collection time of 1 h at 0.4 l min−1. Short-term measurement capability and sensitivity of the Raman method were demonstrated using a transient simulated workplace aerosol. Workplace air and personal breathing zone concentrations of crystalline silica of workers at a hydraulic fracturing worksite were measured using the Raman method. The measurements showed good agreement with the co-located samples analyzed using the standard X-ray powder diffraction (XRD) method, agreeing within 0.15–23.2% of each other. This magnitude of difference was comparable to the inter- and intra-laboratory analytical precision of established XRD and infrared methods. The pilot study shows that for silica-containing materials studied in this work it is possible to obtain quantitative measurements with good analytical figures of merit using handheld or portable Raman spectrometers. Further studies will be needed to assess matrix interferences and measurement uncertainty for several other types of particle matrices to assess the broader applicability of the method.

Thrombolysis Improves Reperfusion and the Clinical Outcome in Tandem Occlusion Stroke Related to Cervical Dissection: TITAN and ETIS Pooled Analysis

Background and Purpose Despite the widespread adoption of mechanical thrombectomy (MT) for the treatment of large vessel occlusion stroke (LVOS) in the anterior circulation, the optimal strategy for the treatment tandem occlusion related to cervical internal carotid artery (ICA) dissection is still debated. This individual patient pooled analysis investigated the safety and efficacy of prior intravenous thrombolysis (IVT) in anterior circulation tandem occlusion related to cervical ICA dissection treated with MT.Methods We performed a retrospective analysis of two merged prospective multicenter international real-world observational registries: Endovascular Treatment in Ischemic Stroke (ETIS) and Thrombectomy In TANdem occlusions (TITAN) registries. Data from MT performed in the treatment of tandem LVOS related to cervical ICA dissection between January 2012 and December 2019 at 24 comprehensive stroke centers were analyzed. The primary endpoint was a favorable outcome defined as 90-day modified Rankin Scale (mRS) score of 0–2.Results The study included 144 patients with tandem occlusion LVOS due to cervical ICA dissection, of whom 94 (65.3%) received IVT before MT. Prior IVT was significantly associated with a better clinical outcome considering the mRS shift analysis (common odds ratio, 2.59; 95% confidence interval [CI], 1.35 to 4.93; P=0.004 for a 1-point improvement) and excellent outcome (90-day mRS 0–1) (adjusted odds ratio [aOR], 4.23; 95% CI, 1.60 to 11.18). IVT was also associated with a higher rate of intracranial successful reperfusion (83.0% vs. 64.0%; aOR, 2.70; 95% CI, 1.21 to 6.03) and a lower rate of symptomatic intracranial hemorrhage (4.3% vs. 14.8%; aOR, 0.21; 95% CI, 0.05 to 0.80).Conclusions Prior IVT before MT for the treatment of tandem occlusion related to cervical ICA dissection was safe and associated with an improved 90-day functional outcome.

Phase Shift Analysis for Alpha-alpha Elastic Scattering using Phase Function Method for Gaussian Local Potential

The phase shifts for α- α scattering have been modeled using a two parameter Gaussian local potential. The time independent Schrodinger equation (TISE) has been solved iteratively using Monte-Carlo approach till the S and D bound states of the numerical solution match with the experimental binding energy data in a variational sense. The obtained potential with best fit parameters is taken as input for determining the phase-shifts for the S channel using the non-linear first order differential equation of the phase function method (PFM). It is numerically solved using 5th order Runge-Kutta (RK-5) technique. To determine the phase shifts for the ℓ=2 and 4 scattering state i.e. D and G-channel, the inversion potential parameters have been determined using variational Monte-Carlo (VMC) approach to minimize the realtive mean square error w.r.t. the experimental data.