全球信息网WWW上的化学资源

文献查阅是化学工作者必须掌握的基本技能之一.随着计算机网络技术的迅速发展,利用全球信息网WWW浏览和获取化学信息已成为查阅化学文献最重要的方法之一.在化学工作者中普及万维网WWW查阅各类化学信息和获取化学资源的方法是非常重要的.作者简要叙述WWW的基本原理和通过WWW获取化学信息和化学资源的方法,并给出部分Internet化学资源.     

Global Intermedia Agenda Setting: A Big Data Analysis of International News Flow

This study contributes to international news flow literature methodologically, by significantly expanding its scope, and theoretically, by incorporating intermedia agenda-setting theory, through which we reveal how news media in different countries influence each other in covering international news. With a big data analysis of 4,708 online news sources from 67 countries in 2015, the study shows that wealthier countries not only continue to attract most of the world news attention, they are also more likely to decide how other countries perceive the world. However, international news flow is not as hierarchical and U.S.-centric as found earlier. Online-only, emerging media in core countries are not necessarily more impactful in setting the world news agenda than those in (semi)peripheral countries.     

The enormity of the zinc deficiency problem and available solutions; an overview

The societal cost of micronutrient deficiency (MND) or the “hidden hunger” is in millions of dollars/year, reducing the GDP of some countries by as much as 11%. Zn is an important micronutrient for both plants and animals. An estimated 17% of the world population, or around 1.1 billion people, are at the risk of zinc (Zn) deficiency. The deficiency has been related to adverse pregnancy outcomes, stunted growth, premature deaths, immune system dysfunctions, neuro-behavioral disorders, and recently with the failure to recover from COVID-19. These health risks associated with Zn deficiency have compelled FAO and WHO to recommend Zn fortification of diet. Correcting Zn deficiency is a challenge due to several reasons. Close to half of the agricultural soils are Zn deficient, and chemical Zn fertilizers are costly and ineffective. Developing Zn-rich crops through plant breeding and genetic engineering is challenging. Zn-dense diet is costly and cannot be implemented in the low-income region most affected by Zn deficiency. Lack of consensus among regulatory bodies on defining and diagnosing Zn deficiency in plants and Humans. Awareness and other sociocultural issues. Among the most important available solutions are zinc biofortification of the cereal crops, use of zinc biofertilizers, development of Zn-efficient crops with reduced phytate content. The use of Zn supplements, dietary modification, and diversification, especially with fish, are proposed as the most accessible and affordable solutions. Awareness programs in areas suffering the most from Zn deficiency are required. Despite the suggestions from FAO and WHO, global efforts to combat Zn deficiency matching those for combating diseases like HIV are not in place. Coordinated efforts of the international community, especially policy-makers, agricultural scientists, dieticians, physicians, and others, are required to address the issue of hidden hunger.     

Nuclear Physics in Norway, 1933–1955

In the late 1940s and the 1950s, Norwegian nuclear scientists, engineers, and administrators were deeply split over their nation’s goals, organization, politics, and tools for research in nuclear physics. One faction was determined to build a nuclear reactor in Norway, while another fiercely opposed the reactor plans and focused on particle accelerators. The first faction comprised scientific entrepreneurs and research technologists, the second academic scientists, most of whom began their research careers in nuclear physics in the 1930s. To understand this conflict, I trace the development of nuclear research in Norway from the early 1930s to the mid-1950s, placing it within an international context. Roland Wittje is working on his habilitation thesis in the History of Science Unit at the University of Regensburg, Germany.     

后3G时代LTE异军突起

介绍了下一代无线网络LTE(Long Term Evolution,长期演进)的背景和发展状况.分析了LTE的技术特征,阐述了LTE网络结构与核心技术,并通过与WiFi(WirelessFidelity)及WiMAX(World wide Inter operability for Microwave Access)的各项性能作比较,着重分析了LTE的技术优势.最后,指出了LTE在个人通信市场所面临的应用前景与挑战.     

Analysis of microcystins by capillary zone electrophoresis coupling with electrospray ionization mass spectrometry

In this paper, a rapid and effective method based on capillary zone electrophoresis (CZE) coupled with electrospray ionization mass spectrometry (ESI-MS) was established for the trace analysis of microcystin (MC) isomers in crude algae sample. The experimental conditions including the composition, acidity and concentration of buffer, separation voltage, injection time, and MS detection parameters were investigated in detail. A capillary separation system was as follows: a uncoated fused-silica capillary tube (50 μm i.d. × 90 cm), 40 mmol L⁻¹ ammonium acetate solution (pH 9.86) as running buffer, 25 kV as separation voltage, 20 kV × 3 s water first and 20 kV × 20 s for sample injection. Mass analysis was performed in ESI source, with sheath gas temperature 150 °C, sheath gas pressure 10 psi, and sheath gas flow 6 L min⁻¹. And sheath liquid was 7.5 mmol L⁻¹ acetic acid in 50% isopropanol-water (3 μL min⁻¹). Protonation and ammonium adduct molecular ions m/z 506.9 (MC-LR) and 532.0 (MC-YR) were used for the quantification of MCs. Under these conditions, two MCs were baseline separated within 9 min, the calibration curves were obtained in the range of 0.11-10.0 μg mL⁻¹ and 0.16-10.5 μg mL⁻¹ for MC-LR and MC-YR, respectively. Meanwhile, limits of detection were 0.05 and 0.08 μg mL⁻¹ for MC-LR and MC-YR, respectively. The recoveries for the two MCs were in the range of 95.8-108%. The developed approach had been successfully applied to the analysis of MCs in crude algae samples.     

世界卫生保健状况评价的统计分析

本文针对反映卫生保健状况的各项指标数据,首先利用数理统计中因子分析的方法,找出反映卫生保健状况的综合因子,并计算各个国家的因子得分,然后根据子得分对各国分别进行排名,最后再用聚类法给出世界卫生保健状况的等级平价。并为促进世界卫生保健事业的发展提出几点建议。     

国际互联网上的光谱学信息资源-Ⅰ

为了促进和方便光谱学工作者利用国际互联网,本文介绍了部分网上光谱学信息资源,主要包括光谱数据库,学术杂志,协会与组织,国际学术会议,与光谱学有着的机构、公司以及一部分光谱学工作者的网站及可检索的内容。     

Synchronization in evolving snowdrift game model

The interaction between the evolution of the game and the underlying network structure with evolving snowdrift game model is investigated. The constructed network follows a power-law degree distribution typically showing scale-free feature. The topological features of average path length, clustering coefficient, degree-degree correlations and the dynamical feature of synchronizability are studied. The synchronizability of the constructed networks changes by the interaction. It will converge to a certain value when sufficient new nodes are added. It is found that initial payoffs of nodes greatly affect the synchronizability. When initial payoffs for players are equal, low common initial payoffs may lead to more heterogeneity of the network and good synchronizability. When initial payoffs follow certain distributions, better synchronizability is obtained compared to equal initial payoff. The result is also true for phase synchronization of nonidentical oscillators.