图书馆数字工作平台体系的Z39.50技术

作为OSI参考模型的应用层协议之一的Z39.50标准,可以实现多点异构数据库检索和不同系统之间的通信.本文从图书馆数字工作平台体系的资源数据整合、资源数据交换和共享、异构数字资源检索三个方面分析了Z39.50标准的原理、技术实现以及Z39.50技术在国内外图书馆界具体应用的典型系统.     

神经癌细胞PC12对二甲基亚砜耐受剂量的分析

通过观察不同剂量二甲基亚砜(dimethyl sulfoxide DMSO)作用下PC12细胞形态和生长状态的变化,确定PC12细胞对DMSO的耐受剂量.按照一定浓度梯度(V/V)将DMSO加入培养液干预后的24、48和72 h于倒置相差显微镜下观察AO/EB染色前后细胞的形态特征,同时用四甲基偶氮唑蓝(MTT)显色法检测细胞的生存率和计算半数抑制浓度(50%inhibiting concentration,IC50).结果表明:DMSO浓度为14 mL/L时,24 h内90%的PC12细胞生长正常,形态完整,活力与对照组比较无差别,浓度提高到20 mL/L时,24 h时细胞生存率可下降27%,随着作用时间延长,细胞生存率进一步降低;24、48和72 h对应的IC50值分别为31.4、23.9和19.2 mL/L.因此,对PC12细胞而言,24 h内的应用终浓度应低于14 mL/L,干预时间如需延长,DMSO的应用剂量应相应降低.     

Evaluating solutions to the problem of false positives

A current challenge for the scientific community is the choice of appropriate policies to reduce the rate of false positives. Existing proposals differ in whether to prioritize tackling omission through transparency requirements, punishing more severe transgressions, or possibly both. We use a formal model to evaluate these possible solutions. We find that a policy that prohibitively increases the cost of ‘misdemeanor’ types of questionable research practices robustly decreases the overall rate of researcher misconduct, because the rate of ‘felonies’, such as fabrication, also decreases. Therefore proposals that aim to prevent lying by omission by enforcing reporting guidelines are likely to be effective in reducing researcher misconduct, but measures such as government audits (purported to counteract pure fraud) can backfire. Moreover, we find that an increase in the rewards of publication need not increase overall misconduct.     

Teacher Perceptions of Parent Engagement at a Cyber High School

A growing number of adolescents are taking all or most of their courses online. This places a greater responsibility on parents to support and facilitate their students' learning. This case study used teacher surveys and interviews to better understand how teachers perceived and supported parents' attempts to support their online students at a single online charter school. The results indicated that teachers observed multiple ways in which parents supported their students by (a) organizing and managing students' schedules, (b) nurturing relationships and interactions, (c) monitoring and motivating student engagement, and (d) instructing students when necessary. However, teachers believed that parents could act as obstacles to their students' learning by being overly engaged in certain types of learning activities. Additional research is needed that examines parent engagement in a variety of online learning environments. Research that identifies best practices could also be especially valuable to online teachers and administrators wishing to improve the quantity and quality of parental engagement in their programs.     

Students' Acceptance of Tablet PCs in the Classroom

In recent years digital technologies, such as tablet personal computers (TPCs), have become an integral part of a school's infrastructure and are seen as a promising way to facilitate students' learning processes. This study empirically tested a theoretical model derived from the technology acceptance model containing key constructs developed in previous research on the acceptance of technological innovations. On the basis of the research model, it was hypothesized that students' acceptance of tablet PCs could be explained by key constructs and could be distinguished in organizational, individual, and technological factors. The survey research was conducted in three German middle schools, involving a total of 120 students. Overall, participants' attitude toward the TPC positively predicted their behavioral intention to use the TPC and as such had the strongest direct influence. The findings emphasize the importance of understanding factors affecting students' attitudes in order to manage and influence the integration of TPCs in schools.     

Krankenanstalten; Arbeits- und Sozialrecht; Gesetzgebungskompetenz

Der Landesgesetzgeber vermag seine Gesetzgebungskompetenz betreffend die angefochtene Bestimmung arbeits- und dienstrechtlichen Inhalts angesichts dieser Komplexit?t weder auf den Kompetenztatbestand des Art 12 Abs 1 Z 1 B-VG "Heil- und Pflegeanstalten", noch auf die Kompetenznorm des Art 21 Abs 1 B-VG zu stützen.     

Instructional Investment or Administrative Bloat: The Effects of Charter System Conversion on Resource Allocations and Staffing Patterns

Despite the growing call for local autonomy and flexibility, few scholars have examined the role of school district–level flexibility on resource allocation and staffing patterns. Leveraging the charter system law within the State of Georgia, we utilize a generalized difference-in-differences approach to estimate the impact of flexibility of system-level expenditures and staffing changes. We find evidence of increases in central office spending and staffing post-conversion to a charter system. In addition, we find evidence that local support is replaced by the state-funded supplemental funding.     

基于微机的12导同步心电波形数据库的建立

介绍了12导同步心电波形数据库生成系统的设计过程及180例波形数据库建立的步骤。该数据库的建立对我国心电分析和诊断自动化进程有着重要的意义。     

Understanding problem solving behavior of 6–8 graders in a debugging game

Debugging is an over-looked component in K-12 computational thinking education. Few K-12 programming environments are designed to teach debugging, and most debugging research were conducted on college-aged students. In this paper, we presented debugging exercises to 6th–8th grade students and analyzed their problem solving behaviors in a programming game – BOTS. Apart from the perspective of prior literature, we identified student behaviors in relation to problem solving stages, and correlated these behaviors with student prior programming experience and performance. We found that in our programming game, debugging required deeper understanding than writing new codes. We also found that problem solving behaviors were significantly correlated with students’ self-explanation quality, number of code edits, and prior programming experience. This study increased our understanding of younger students’ problem solving behavior, and provided actionable suggestions to the future design of debugging exercises in BOTS and similar environments.     

热平衡过程与RL电路暂态过程的比较

在研究热平衡随时间变化过程的规律时,根据相似性原理,通过和电磁学中的RL电路暂态过程的对比,得出其基本物理规律。