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971.
972.
973.
Kateřina Sv. Gillárová 《Journalism Practice》2014,8(5):607-618
Rapidly changing working conditions in recent years, along with the need to reduce the costs of news production, require journalists to adapt. Our suggestion here is that many of the research methods for analysing journalists' work environments to date are no longer sufficient for capturing this ongoing change. In searching for new approaches to analysis of the journalistic environment, we decided to apply visual ethnography, a method not yet used in the Czech Republic and not much used in the world beyond. For our pilot study of Czech newsrooms, we worked with both photographs taken of the journalists involved in our project and photographs taken by our research team (photographs showed both journalists' working conditions and working processes). We then interviewed the journalists about the photographs and more widely about their working practices and conditions. This paper presents the results of the research but also considers the advantages and challenges of the visual ethnographic approach and its implementation in media environments. 相似文献
974.
Leticia I. RAMíREZ-CAVAZOS Charles JUNGHANNS Rakesh NAIR Diana L. CáRDENAS-CHáVEZ Carlos HERNáNDEZ-LUNA Spiros N. AGATHOS Roberto PARRA 《Journal of Zhejiang University. Science. B》2014,15(4):343-352
研究目的:优化获得血红密孔菌(P.sanguineus)的最佳培养基组成,提高耐热漆酶的产量。创新要点:获得了目前文献报道的最高水平的漆酶活力。研究方法:通过单因素试验研究了不同培养基(番茄汁、麦麸、麦芽提取物和葡萄糖细菌蛋白胨培养基)和不同组合诱导剂(大豆油、阿魏酸、没食子酸、二甲基苯胺、酸性蓝62和活性蓝19分别与硫酸铜组合诱导剂)对P.sanguineus产耐热漆酶的影响。在此基础上采用中心组合试验设计,进一步研究了番茄汁培养基结合硫酸铜和大豆油组合诱导剂对P.sanguineus产耐热漆酶的影响。利用SAS10.0和响应面分析方法对试验结果进行了统计分析和建立回归模型。重要结论:通过中心组合设计优化得出P.sanguineus产耐热漆酶的最优培养基条件:以36.8%番茄汁为培养基,以3 mmol/L硫酸铜和1%大豆油作为组合诱导剂。该条件下在10 L搅拌槽生物反应器中漆酶活力达到了143 000 IU/L(2,2'-联氮双(3-乙基苯并噻唑啉-6-磺酸)为底物,pH值为3.0)。 相似文献
975.
Daniel E. Vigo Guido Simonelli Ianina Tuñón Daniel Pérez Chada Daniel P. Cardinali Diego Golombek 《Mind, Brain, and Education》2014,8(4):175-181
Sleep in adolescents has been shown to be an important factor when looking at physical, mental, and social well‐being. Little evidence is found regarding sleep patterns in adolescents from households facing extreme poverty, where conditions such as crowding, poor housing, sanitation or education, and precarious employment set an adverse environment for sleep. In this study, we sought to assess in a nationwide sample comprised of 1,682 adolescents from Argentina, how the presence of extreme poverty—as defined by the presence of unsatisfied basic needs (UBN)—affects the relationship of sleep duration with school, work, and other daily activities. A global high prevalence of short sleeping time, a slight increase of sleep time in adolescents with UBN, and different patterns of wake activities that predict sleep deficit, depending on the presence of UBN, were found. The poor academic achievement, increased risk of accidents, and adverse health outcomes associated with sleep deprivation support the view that sleep is an additional unsatisfied basic need that worsens living conditions at this age. The results may help to design public health policies that contribute to ameliorate this adverse situation. 相似文献
976.
Social networks provide individuals with diverse or redundant information depending on the network structure. Both types of information offer advantages for generating new ideas. At the same time, network structure and network content are independent. As a result, two individuals with the same network position can access diverse or redundant content from their social peers. In this study, we investigate the function of social networks in innovative endeavors given individuals’ different kinds of information accessing behavior. In accordance with previous research, we argue that individuals with a broker status access more diverse information through non-redundant network structures and develop, on average, more novel ideas. We further propose that redundancy in content complements brokers’ structural non-redundancy by providing familiar knowledge elements and therefore interpretability, while non-redundancy in both content and structure leads to information overload. Thus, we hypothesize that brokers accessing more information depth, and independently, less information breadth generate newer ideas. To test our hypotheses, we collected data from a popular online maker community containing 18,146 ideas, 19,919 profiles, and 52,663 comments. We used topic modeling (Latent Dirichlet Allocation) to extract hidden knowledge elements and social network analysis to identify brokers. In line with our hypotheses, we find that information depth (breadth) strengthens (weakens) a favorable broker position. These findings have implications for the literature on idea generation in social networks and household sector innovation. 相似文献
977.
AN Pisarchik R Jaimes-Reátegui C Rodríguez-Flores JH García-López G Huerta-Cuellar FJ Martín-Pasquín 《Journal of The Franklin Institute》2021,358(4):2561-2575
Extreme multistability is the coexistence of a large number of attractors which can be reached by varying initial conditions. In this paper we show how this fascinating phenomenon can be used for secure communication. The main advantage of the communication system based on extreme multistability over a conventional chaos-based communication system is its exceptionally high security. The proposed system consists of two identical six-order oscillators; one in the transmitter and another one in the receiver, each exhibiting the coexistence of a large number of chaotic attractors. The oscillators are synchronized using a private channel through one of the system variables, while the information is transmitted via a public channel through another variable. The information is encrypted by varying the initial condition of one of the state variables in the transmitter using a chaotic map, adhering message packages in a staggered form to the coexisting attractors within the same time series of another state variable, which leads to switching among the coexisting chaotic attractors. To ensure communication security, the duration of the packages is shorter than synchronization time, so that synchronization attacks are ineffective. 相似文献
978.
Guillermo Oaxaca-Adams Raúl Villafuerte-Segura Baltazar Aguirre-Hernández 《Journal of The Franklin Institute》2021,358(9):4671-4686
In this paper an explicit numerical procedure is proposed to determine the non-fragility of parameters of controllers used to stabilize a class of time delay systems. The proposed procedure finds the largest possible circle inscribed in a stability subregion delimited by a simple closed curve in the plane of the controller parameters. The center of this circle is declared to be the controller’s least fragile parameters. The obtained theoretical results are applied and compared with some of the most relevant examples found in the literature. This illustrates that the proposed procedure improves previous results found in the literature so far. 相似文献
979.
Ladislava Zbiejczuk Suchá Eliška Bartošová Roman Novotný Jiřina Bělehradová Svitáková Tomáš Štefek Eva Víchová 《Library & information science research》2021,43(1):101068
Public libraries have a huge potential to be creators and facilitators of social innovation in communities and society. Qualitative research based on interviews with 27 librarians showed that social innovation in libraries can take the form of educational and cultural activities, leisure and networking activities and social support services. The main goal of the research was to find out what factors support and make these innovations difficult in public libraries. A four-layer model of barriers and stimulators for social innovation is presented, which includes structural, local, organizational and personnel levels. The model could serve to inform librarians, their stakeholders and governments about all levels of barriers and stimulators connected to innovation of library services and social re-positioning of public libraries in the future. 相似文献
980.
Hernán Cofré Claudia Vergara Norman G. Lederman Judith S. Lederman David Santibáñez Javier Jiménez Macarena Yancovic 《Journal of Science Teacher Education》2014,25(7):759-783
Understanding nature of science (NOS) is considered critical to the development of students’ scientific literacy. However, various studies have shown that a large number of elementary and secondary science teachers do not possess an adequate understanding of NOS. This study investigated how elementary teachers’ understanding of NOS was impacted through a 1-year professional development program in Chile that included NOS instruction as a theme throughout two types of mini-courses in the program. Twelve teachers attended a 1-year development program focused on improving teacher content knowledge and included the instruction of NOS embedded in two self-contained NOS mini-courses (36 h) and two lessons (3 h each) within five science content mini-courses (30 h). The Views of NOS (version D+) questionnaire and interviews were used to assess teachers’ understanding of NOS at the beginning (January) and end of the program (December). Elementary teachers’ understanding of the creative, inferential, and tentative aspect of NOS showed improvement. According to the teachers’ perceptions, the most significant activities for improving their NOS understanding were decontextualized activities in both types of mini-courses (self-contained NOS and science content mini-courses). The implications for professional development programs are also discussed. 相似文献