A Confluence of Tech and Talent: Rural Online Entrepreneurship and Return Migration

The vast majority of those living in poverty reside in rural areas. Prior research indicates that the Internet can elevate the rural economy by connecting rural entrepreneurs to the wider market. However, we have yet to witness much successful online entrepreneurship in rural areas. In this study, we show that return migration is a crucial factor for the performance of e-commerce in rural areas. Using data from a leading ecommerce platform, we set up a natural experiment involving a provincial-level policy change that reduced the barriers for talented rural migrants to return and work in their home villages. In a difference-in-differences design, we find that after the policy change, rural e-commerce businesses in the province that implemented the policy change enjoyed a 22 percent performance gain relative to other rural businesses. This study suggests that policymakers and digital platforms need to create a confluence of talent and technology to spur successful entrepreneurship in rural areas

Cross-linguistic Investigation of AI-assisted Written Communication

This study aims to investigate the effectiveness of AI usage in written communication across three languages: English, Arabic, and Chinese. In an online experiment, participants will be randomly assigned to either use AI-generated answers to assist in writing a managerial email plan or to write the plan without AI assistance. The quality of the written plans will be assessed by trained evaluators using predefined criteria. The study will explore the main effects and interactions between AI usage and language groups on the quality of written communication and participants' reactions. Heterogeneous effects will also be analyzed

Fluid-Cooled Compact X-Ray Tube and System Including the Same

A fluid-cooled compact x-ray system includes a compact x-ray tube and a coolant channel coupled thereto. The compact x-ray tube includes a tube housing defining a longitudinal axis, and an electron source in the tube housing and coaxial with the tube housing. The electron source is configured to generate an electron beam. The compact x-ray tube also includes an anode coaxial with the tube housing, the anode defining a plane perpendicular to the longitudinal axis and including a target material, and an electron focusing mechanism in the tube housing and configured to focus and accelerate the electron beam to the anode. The target material of the anode generates a high-energy x-ray beam as a result of bremsstrahlung interaction. The anode defines an interface between the tube housing and the coolant channel. The coolant channel includes a channel housing, and a coolant configured to dissipate heat from the anode

Which COVID policies are most effective? A Bayesian analysis of COVID-19 by jurisdiction.

This paper reports the results of a Bayesian analysis on large-scale empirical data to assess the effectiveness of eleven types of COVID-control policies that have been implemented at various levels of intensity in 40 countries and U.S. states since the onset of the pandemic. The analysis estimates the marginal impact of each type and level of policy as implemented in concert with other policies. The purpose is to provide policymakers and the general public with an estimate of the relative effectiveness of various COVID-control strategies. We find that a set of widely implemented core policies reduces the spread of virus but not by enough to contain the pandemic except in a few highly compliant jurisdictions. The core policies include the cancellation of public events, restriction of gatherings to fewer than 100 people, recommendation to stay at home, recommended restrictions on internal movement, implementation of a partial international travel ban, and coordination of information campaigns. For the median jurisdiction, these policies reduce growth rate in new infections from an estimated 270% per week to approximately 49% per week, but this impact is insufficient to prevent eventual transmission throughout the population because containment occurs only when a jurisdiction reduces growth in COVID infection to below zero. Most jurisdictions must also implement additional policies, each of which has the potential to reduce weekly COVID growth rate by 10 percentage points or more. The slate of these additional high-impact policies includes targeted or full workplace closings for all but essential workers, stay-at-home requirements, and targeted school closures

Intermodal Competition and Pricing in Grain Transportation: A Description and Comparison of Methods

Demand and Price Analysis, Public Economics,

Particle-In-Cell Simulations of Electron Focusing for a Compact X-Ray Tube Comprising CNT-Based Electron Source and Transmission Type Anode

For real-time computed tomography (CT), a temporal resolution lower than 30 ms is required, which cannot be delivered by conventional CT architectures with a rotation gantry. Stationary CT architecture can achieve a temporal resolution lower than 30 ms by eliminating the physical rotation of the gantry and by electronically sweeping X-ray beams across the gantry. Stationary CT architecture utilizes two separate arrays, one for distributed X-ray sources and another for detectors. These individual X-ray sources are required to be compact, fast, and individually addressable in order to acquire 200+ projections for successful CT reconstruction and to achieve a temporal resolution lower than 30 ms. A compact X-ray tube that fits these requirements is being developed. The aim of this paper was to design an electrostatic electron focusing lens for the first-generation prototype compact X-ray tube primarily consisting of a carbon nanotube-based electron source and a transmission-type anode by studying the multiple variables that affect the focal spot size (FSS) and by comparing different types of electrostatic lenses with the help of simulations. This multivariable simulation study was conducted using an object-oriented particle-in-cell code, OOPIC PRO. The results of these simulations showed the following: Einzel lens can achieve the required FSS (lower than 1 mm); lens aperture, thickness, and location of the lens can be used as a coarse control over the FSS, whereas the lens potential can be used as a fine control; and the chromatic and spherical aberrations can be reduced if Einzel lens is used

3D Characterization of Structure and Micro-Porosity in Two Cast Irons with Spheroidal Graphite

Formation of low density graphite phase during solidification increases the volume of semi-solid cast iron with spheroidal graphite (SGI) and resulted pressure could help eliminate shrinkage micro-porosity in casting. Therefore, micro-porosity in casting can be linked to 3D graphite nodule structure. Two experimental SGI\u27s with different levels of shrinkage micro-porosity in castings were intentionally produced by variation in inoculation parameters which influenced graphite nodule structure. 3D-morphological characteristics of graphite nodules and micro-porosity level were determined by µCT scanning. The obtained statistical data was discussed with respect to graphite nodule solidification mode and casting soundness. The capabilities of µCT scanning in predicting micro-shrinkage in SGI casting were compared to the other traditionally used techniques

Micro-CT Quantitative Evaluation of Graphite Nodules in SGI

The quality of spheroidal graphite cast iron (SGI) castings is directly related to the morphology of graphite nodules. Therefore, accurate and comprehensive quantitative evaluation of microstructure is critical for industrial practices. The most influential morphological characteristics of the graphite phase in SGI can be divided into three categories: (1) shape and size of individual graphite nodules, (2) total volume of graphite phase and nodule number, and (3) spatial distribution. During the last decades, SGI structure analysis has progressed from visual observation of polished cross section and quantitative 2D techniques (metallography and automated SEM/EDX) to observation of the real 3D structure using micro-computed tomography (µCT) scanning. In this article, 2D and 3D morphological characteristics of graphite nodules were determined by µCT scanning and compared. 3D µCT provides accurate characterization of the real shape factor and diameter of graphite nodules. It was shown that large and small graphite nodules in inoculated SGI have the different modes of space distribution which could be linked to casting solidification