上游垄断与制造业资源错配

基于目前中国“上游行业垄断,下游行业竞争”的现实背景,本文利用1998-2007年的制造业企业数据,系统分析了上游垄断引起的资源错配效应。研究发现,上游垄断对我国制造业资源错配具有显著的正向推动作用,并且产品市场扭曲和要素市场扭曲是上游垄断恶化我国资源配置效率的重要渠道,而中间品贸易自由化可以在一定程度上缓解此效应。测算结果显示,在样本期间,上游垄断引致的资源错配效率损失占总资源错配效率损失的比重为25.81%-30.20%,且两种机制的贡献大致相等。如果不存在上游垄断现象,则生产率将在总体上平均提升4.49%-9.05%。因此,加快上游行业市场化改革进程对于提高我国资源配置效率具有重要的意义。

“走向同情的政治”:特邀编辑介绍与概述

2023年1月,塞缪尔·韦伯应我和上海大学之邀,在线上作了三场系列讲座。讲座是2022年10月在巴黎初步构思的,当时的想法是讲座内容可以在某种程度上继续他在2022年刚出版的新书《先存条件:重述瘟疫》(Preexisting Conditions:Recounting the Plague,区域图书出版社)中对新冠疫情经历的思考,同时考虑到近两年国内文学和批评理论界的部分同行对他在2021年出版的著作《独异性:政治和诗学》(Singularity:Politics and Poetics,明尼苏达大学出版社)中的“独异性”概念也甚为关注,因此我们商定讲座的内容将综合这两部近作中的一些重要概念和文献,同时保持其开放性,自然地融入韦伯目前正在思考和撰写的新的主题。

4种热带睡莲营养成分对比分析

以热带睡莲为研究对象,分别对其花瓣和茎的含水量、灰分、蛋白质、粗脂肪、可溶性糖、维生素C、氨基酸种类和含量进行测定。结果显示,4种热带睡莲花瓣和茎段的含水量都很丰富,可溶性糖含量较高,尤其粉睡莲茎可溶性糖含量最高,达到345.97mg/g,脂肪和蛋白质均有检测出,并含有一定量的维生素C和多种氨基酸,其中粉睡莲花瓣的总氨基酸含量高达193.86mg/100g,蓝睡莲花瓣中必需氨基酸含量高达45.07mg/100g,均为种理想的菜用睡莲。通过综合比较分析,热带睡莲花瓣和茎均有一定的食用价值,可以在市场上进行推广。

AZ31B镁合金快速冷却搅拌摩擦焊缝厚度方向的显微组织和力学性能

采用电子背散射衍射仪和透射电子显微镜研究快速冷却对6 mm厚AZ31B镁合金搅拌摩擦焊缝厚度方向的显微组织和力学性能的影响。结果表明,液态二氧化碳冷却可促进焊缝顶部形成具有高位错密度、大量{1012}孪晶和第二相颗粒的细晶结构。{1012}孪晶使焊缝顶部区域的基面织构显著降低。接头顶部区域的强度和断后伸长率较底部区域均明显提高,焊接效率可达93%。这为在镁合金搅拌摩擦焊接头中制备梯度结构提供一种简单有效的方法。

5种铜绿假单胞菌高危克隆的流行及耐药情况

细菌引起的感染分为社区感染和医院内感染,社区感染的细菌通常对抗生素敏感,较容易控制,而院内感染较难治疗。铜绿假单胞菌(Pseudomonas aeruginosa)是机会性感染的非发酵革兰阴性细菌,一种引起医院内感染的常见细菌,并容易感染术后患者及烧伤患者,影响患者的治疗与恢复。抗生素治疗是人们抵御细菌感染性疾病的有效手段,但是随着抗生素的大量使用,抗生素耐药性细菌不断产生,泛耐药(extensively drug resistant, XDR)甚至是全耐药(pandrug-resistant bacteria, PDR)铜绿假单胞菌已在世界多地医院被检出。而这种广泛的耐药性往往集中在几种特定的铜绿假单胞菌基因型中,如ST111、ST175、ST235、ST308和ST664等;由于无药可用,使得它们所引发的感染异常危险,因此被称为高危克隆。本文就目前国际流行的5种铜绿假单胞菌高危克隆进行系统性综述,包括其流行情况、耐药谱、耐药机制及治疗手段,为高危克隆的甄别和防治提供借鉴。

Induction of Apoptosis in the Immature Mouse Testes by a Mixture of Melamine and Cyanuric Acid

The toxicity of melamine has attracted much attention since the recent outbreaks of renal injury in pets and infants. Previous studies indicated that melamine by itself had low toxicity, whereas a mixture of melamine and cyanuric acid （M＋CA） could cause serious renal damage. At present, most researches on the toxicity of M＋CA are focused on the kidney. However, little is known about the adverse effects of this mixture on the reproductive system. In the present study, the toxicity of M＋CA to testes was investigated. Immature male mice were orally dosed with 0, 0.6, 3, and 15 mg kg-1 d-1 of a 1：1 M＋CA for 28 d. Pathological changes occurred in germ cells, such as loose arrangement, reduced numbers and karyopyknosis, indicating that this mixture was toxic to spermatogenesis. Compared with the control group, the TUNEL- positive germ cells increased significantly and the ratio of Bcl-2 to Bax, total antioxidant capacity and superoxide dismutase activity decreased significantly in the 3 and 15 mg kg-1 d- M＋CA treated group, while the activities of caspase-3, caspase- 8 and caspase-9 remained unchanged. The results suggest that M＋CA can induce apoptosis in the mice testes. The downregulation of Bcl-2/Bax and oxidative stress may play a pivotal role in the induction of apoptosis by M＋CA in mice testes.

A New Method of Early Short Circuit Detection

To reduce the pressure on contacts and circuit breaker and realize the zone selective interlocking (ZSI) function above the instantaneous protection threshold (e.g., >10In), the short circuit current needs to be early detected. The state-of–art of early short circuit detection (ESCD) method is reviewed. Based on the equivalent model of the short circuit, a new method based on the current and its integration is proposed. The prospective current value can be detected in the early stage of the short circuit. According to the evaluation result, the short circuit current can be early forecasted with the proposed method.

One-Variable Attack on the Industrial Fault Classification System and Its Defense

Recently developed fault classification methods for industrial processes are mainly data-driven.Notably,models based on deep neural networks have significantly improved fault classification accuracy owing to the inclusion of a large number of data patterns.However,these data-driven models are vulnerable to adversarial attacks;thus,small perturbations on the samples can cause the models to provide incorrect fault predictions.Several recent studies have demonstrated the vulnerability of machine learning methods and the existence of adversarial samples.This paper proposes a black-box attack method with an extreme constraint for a safe-critical industrial fault classification system:Only one variable can be perturbed to craft adversarial samples.Moreover,to hide the adversarial samples in the visualization space,a Jacobian matrix is used to guide the perturbed variable selection,making the adversarial samples in the dimensional reduction space invisible to the human eye.Using the one-variable attack(OVA)method,we explore the vulnerability of industrial variables and fault types,which can help understand the geometric characteristics of fault classification systems.Based on the attack method,a corresponding adversarial training defense method is also proposed,which efficiently defends against an OVA and improves the prediction accuracy of the classifiers.In experiments,the proposed method was tested on two datasets from the Tennessee–Eastman process(TEP)and steel plates(SP).We explore the vulnerability and correlation within variables and faults and verify the effectiveness of OVAs and defenses for various classifiers and datasets.For industrial fault classification systems,the attack success rate of our method is close to(on TEP)or even higher than(on SP)the current most effective first-order white-box attack method,which requires perturbation of all variables.

Laser particles with omnidirectional emission for cell tracking

The ability to track individual cells in space over time is crucial to analyzing heterogeneous cell populations.Recently,microlaser particles have emerged as unique optical probes for massively multiplexed single-cell tagging.However,the microlaser far-field emission is inherently direction-dependent,which causes strong intensity fluctuations when the orientation of the particle varies randomly inside cells.Here,we demonstrate a general solution based on the incorporation of nanoscale light scatterers into microlasers.Two schemes are developed by introducing either boundary defects or a scattering layer into microdisk lasers.The resulting laser output is omnidirectional,with the minimum-to-maximum ratio of the angle-dependent intensity improving from 0.007(-24 dB)to>0.23(-6dB).After transfer into live cells in vitro,the omnidirectional laser particles within moving cells could be tracked continuously with high signal-to-noise ratios for 2 h,while conventional microlasers exhibited frequent signal loss causing tracking failure.

Segmental hair analysis for flunitrazepam and 7-aminoflunitrazepam in users:a comparison to existing literature

The availability of more quantitative data on flunitrazepam(FLU)and 7-aminoflunitrazepam(7AF)would aid in obtaining a better understanding of the interpretation of FLU concentrations in human hair.The purpose of this study was to provide concentrations of FLU and 7AF in hair segments of 22 FLU users.Quantitative data regarding hair concentrations of FLU and 7AF from various types of cases were also reviewed to give a comprehensive overview of the comparability of different studies.Three to six 1 cm segments of scalp hair from 22 FLU users were analyzed by a liquid chromatography–tandem mass spectrometry(LC–MS/MS)method.FLU and its metabolite were confirmed in the hair segments from all cases.Concentrations of FLU and 7AF in the segments ranged from 0.01–0.16 ng/mg(median of 0.03)and 0.01–0.34 ng/mg(median of 0.09),respectively.Most cases had FLU and 7AF distributions along the hair segments that were suggestive of repeated drug use.A summary of the published concentrations gives valuable data and can assist forensic investigators in their estimations of drug use history and patterns.

Quantitative analysis of focal adhesion dynamics using photonic resonator outcoupler microscopy (PROM)

Focal adhesions are critical cell membrane components that regulate adhesion and migration and have cluster dimensions that correlate closely with adhesion engagement and migration speed.We utilized a label-free approach for dynamic,long-term,quantitative imaging of cell–surface interactions called photonic resonator outcoupler microscopy(PROM)in which membrane-associated protein aggregates outcoupled photons from the resonant evanescent field of a photonic crystal biosensor,resulting in a highly localized reduction of the reflected light intensity.By mapping the changes in the resonant reflected peak intensity from the biosensor surface,we demonstrate the ability of PROM to detect focal adhesion dimensions.Similar spatial distributions can be observed between PROM images and fluorescence-labeled images of focal adhesion areas in dental epithelial stem cells.In particular,we demonstrate that cell–surface contacts and focal adhesion formation can be imaged by two orthogonal label-free modalities in PROM simultaneously,providing a general-purpose tool for kinetic,high axial-resolution monitoring of cell interactions with basement membranes.