Applying Minimum-Risk Criterion to Stochastic Hub Location Problems

AbstractThis paper presents a new class of two-stage stochastic hub location (HL) programming problems with minimum-risk criterion, in which uncertain demands are characterized by random vector. Meanwhile we demonstrate that the twostage programming problem is equivalent to a single-stage stochastic P-model. Under mild assumptions, we develop a deterministic binary programming problem by using standardization, which is equivalent to a binary fractional programming problem. Moreover, we show that the relaxation problem of the binary fractional programming problem is a convex programming problem. Taking advantage of branch-and-bound method, we provide a number of experiments to illustrate the efficiency of the proposed modeling idea

Inclusiveness in mental health research: a survey of attitudes, awareness, and actions among journal editors

Background: Improving inclusiveness in mental health research merits attention as we seek to reduce inequalities in mental health. Academic journals can promote inclusiveness through editorial practices related to the selection of content and the composition of journal editorial boards. Objectives: To investigate the attitudes, awareness, and actions of journal editors con-cerning inclusiveness in mental health research and editorial practices. Methods: We surveyed 74 chief and senior editors, representing 55 prominent journals in neuroscience, psychiatry, and psychology (2021 impact factor M = 8.04, SD = 10.76). Results: Most respondents (74–99%) acknowledged the importance of inclusiveness in mental health research, and a majority (62–78%) were familiar with existing guide-lines. Half or fewer of the journals (49–50%) had policies for selecting content that is diverse, and 20% had policies regarding inclusion of individuals with lived experience of mental health challenges. Well over half the journals (57–72%) had policies to widen diversity among their editorial boards and roughly half (43–53%) among peer reviewers, although only a few (18–23%) included among their editors or peer reviewers individuals with lived experience of dealing with mental health challenges. Conclusions: This study highlighted an intention-action gap, with positive attitudes and awareness but limited editorial practices promoting inclusiveness in mental health research. Inclusion of individuals with lived experience emerged as an area in particular need of improvement. We discuss potential strategies that journals might consider to foster inclusiveness, such as diversity training, publication checklists, and infrastructure that supports participatory approaches

Stock Market Volatility, Speculative Short Sellers and Weekend Effect: International Evidence

We test the Chen and Singal (2003) hypothesis that speculative short sellers add to the selling pressure on Mondays, and hence add to the weekend effect, by examining evidence from 60 market indices. We find strong evidence that, until about a decade ago, the actions of short sellers could explain the weekend ef- fect. Recently, however, the relationship between short sales and the weekend effect is gradually dissi- pating in developed markets, probably due to the cross-market hedges of short sellers. These findings strongly support, rather than weaken, the Chen and Singal hypothesis

Stock Market Volatility, Speculative Short Sellers and Weekend Effect: International Evidence

We test the Chen and Singal (2003) hypothesis that speculative short sellers add to the selling pressure on Mondays, and hence add to the weekend effect, by examining evidence from 60 market indices. We find strong evidence that, until about a decade ago, the actions of short sellers could explain the weekend ef- fect. Recently, however, the relationship between short sales and the weekend effect is gradually dissi- pating in developed markets, probably due to the cross-market hedges of short sellers. These findings strongly support, rather than weaken, the Chen and Singal hypothesis

Crystallization Control of N,N′-Dioctyl Perylene Diimide by Amphiphilic Block Copolymers Containing poly(3-Hexylthiophene) and Polyethylene Glycol

The preparation of micron- to nanometer-sized functional materials with well-defined shapes and packing is a key process to their applications. There are many ways to control the crystal growth of organic semiconductors. Adding polymer additives has been proven a robust strategy to optimize semiconductor crystal structure and the corresponding optoelectronic properties. We have found that poly(3-hexylthiophene) (P3HT) can effectively regulate the crystallization behavior of N,N′-dioctyl perylene diimide (C8PDI). In this study, we combined P3HT and polyethylene glycol (PEG) to amphiphilic block copolymers and studied the crystallization modification effect of these block copolymers. It is found that the crystallization modification effect of the block copolymers is retained and gradually enhanced with P3HT content. The length of C8PDI crystals were well controlled from 2 to 0.4 μm, and the width from 210 to 35 nm. On the other hand, due to the water solubility of PEG block, crystalline PEG-b-P3HT/C8PDI micelles in water were successfully prepared, and this water phase colloid could be stable for more than 2 weeks, which provides a new way to prepare pollution-free aqueous organic semiconductor inks for printing electronic devices

A spectral data release for 104 Type II Supernovae from the Tsinghua Supernova Group

We present 206 unpublished optical spectra of 104 type II supernovae obtained by the Xinglong 2.16m telescope and Lijiang 2.4m telescope during the period from 2011 to 2018, spanning the phases from about 1 to 200 days after the SN explosion. The spectral line identifications, evolution of line velocities and pseudo equivalent widths, as well as correlations between some important spectral parameters are presented. Our sample displays a large range in expansion velocities. For instance, the Fe~{\sc ii} $5169$ velocities measured from spectra at $t\sim 50$ days after the explosion vary from ${\rm 2000\ km\ s^{-1}}$to${\rm 5500\ km\ s^{-1}}$, with an average value of${\rm 3872 \pm 949\ km\ s^{-1}}$. Power-law functions can be used to fit the velocity evolution, with the power-law exponent quantifying the velocity decline rate. We found an anticorrelation existing between H$\beta$velocity at mid-plateau phase and its velocity decay exponent, SNe II with higher velocities tending to have smaller velocity decay rate. Moreover, we noticed that the velocity decay rate inferred from the Balmer lines (i.e., H$\alpha$and H$\beta$) have moderate correlations with the ratio of absorption to emission for H$\alpha$ (a/e). In our sample, two objects show possibly flash-ionized features at early phases. Besides, we noticed that multiple high-velocity components may exist on the blue side of hydrogen lines of SN 2013ab, possibly suggesting that these features arise from complex line forming region. All our spectra can be found in WISeREP and Zenodo