Variations in cadmium and nitrate co-accumulation among water spinach genotypes and implications for screening safe genotypes for human consumption     

Lin Tang  Wei-jun Luo  Zhen-li He  Hanumanth Kumar Gurajala  Yasir Hamid  Kiran Yasmin Khan  Xiao-e Yang 《Journal of Zhejiang University. Science. B》2018,19(2):147-158

Vegetables are important constituents of the human diet. Heavy metals and nitrate are among the major contaminants of vegetables. Consumption of vegetables and fruits with accumulated heavy metals and nitrate has the potential to damage different body organs leading to unwanted effects. Breeding vegetables with low heavy metal and nitrate contaminants is a cost-effective approach. We investigated 38 water spinach genotypes for low Cd and nitrate co-accumulation. Four genotypes, i.e. JXDY, GZQL, XGDB, and B888, were found to have low co-accumulation of Cd (<0.71 mg/kg dry weight) and nitrate (<3100 mg/kg fresh weight) in the edible parts when grown in soils with moderate contamination of both Cd (1.10 mg/kg) and nitrate (235.2 mg/kg). These genotypes should be appropriate with minimized risk to humans who consume them. The Cd levels in the edible parts of water spinach were positively correlated with the concentration of Pb or Zn, but Cd, Pb, or Zn was negatively correlated with P concentration. These results indicate that these three heavy metals may be absorbed into the plant in similar proportions or in combination, minimizing the influx to aerial parts. Increasing P fertilizer application rates appears to prevent heavy metal and nitrate translocation to shoot tissues and the edible parts of water spinach on co-contaminated soils.  相似文献   

Factors affecting the motivation to learn among United Arab Emirates middle and high school students     

Vivian Khamis  Samir Dukmak  Hala Elhoweris 《Educational studies》2008,34(3):191-200

This study was designed to examine the relative contributions of student and parents’ socio‐demographics, students’ beliefs about learning, parental support of children’s learning, peers’ attitudes towards learning, teacher–student interaction and curriculum content to students’ motivation to learn. The sample consisted of 275 school‐age children ranging from 12 to 16 years old. All measures were constructed for the purpose of this study. Hierarchical multiple regression was used to predict student motivation to learn. Results indicated that students’ beliefs about learning, teacher–student interaction and curriculum content contributed to the United Arab Emirates middle and high school students’ motivation to learn. Implications for research are discussed.  相似文献   

Digital repositories ten years on: what do scientific researchers think of them and how do they use them?     

David NICHOLAS  Ian ROWLANDS  Anthony WATKINSON  David BROWN  Hamid R. JAMALI 《Learned Publishing》2012,25(3):195-206

Digital repositories have been with us for more than a decade, and despite the considerable media and conference attention they engender, we know very little about their use by academics. This paper sets out to address this by reporting on how well they are used, what they are used for, what researchers' think of them, and where they thought they were going. Nearly 1,700 scientific researchers, mostly physical scientists, responded to an international survey of digital repositories, making it the largest survey of its kind. High deposit rates were found and mandates appear to be working, especially with younger researchers. Repositories have made significant inroads in terms of impact and use despite, in the case of institutional repositories, the very limited resources deployed. Subject repositories, like arXiv and PubMed Central, have certainly come of age but institutional repositories probably have not come of age yet although there are drivers in place which, in theory anyway, are moving them towards early adulthood.  相似文献   

Special relativity, causality and quantum mechanics — 2     

Guruprasad Kar  Samir Kunkri  Sujit K. Choudhary 《Resonance》2006,11(9):43-54

We discuss the aspects of non-locality and nonseparability of states of composite quantum systems. The probabilistic nature of quantum mechanical predictions, and the impossibility of cloning, are shown to safeguard causality in the quantum world. An example of a game which can be won exploiting quantum entanglement, but which can never be won classically, is described.  相似文献   

Special relativity, causality and quantum mechanics — 1     

Guruprasad Kar  Samir Kunkri  Sujit K. Choudhary 《Resonance》2006,11(8):41-52

We discuss the significance of Einstein’s second postulate of the special theory of relativity (STR) stipulating the constancy of the speed of light in vacuum. The causality that follows from the STR may be a more general principle to organize our knowledge of all phenomena. In particular, quantum dynamics can be derived using the causality principle. Causality does not prohibit quantum mechanics to be non-local, and this has implications in the real world.  相似文献   

ANCHORING ADHD SYMPTOMS TO MENTAL AGE     

Callie Martin  Mardis Dunham  Samir H. Patel  Susana Contreras‐Bloomdahl 《Psychology in the schools》2016,53(9):926-937

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM‐5), requires that symptoms of ADHD must be developmentally inappropriate in order for an ADHD diagnosis to be considered. Because the DSM‐5 does not specifically outline procedure for determining developmental inappropriateness of behaviors, practitioners do not have guidance for making this consideration. To explore the relationship between mental age and behavior ratings of ADHD symptoms, the cognitive and behavioral data from 50 children who were evaluated in a school or clinic were compiled for this study. Cognitive ability scores were used to calculate mental age and behavior rating scores were then recalculated using the assessed mental age. Using the recalculated behavior ratings, scores based on mental age decreased significantly on the Attention Problems, Hyperactivity, and Atypicality scales of the BASC‐2. Additionally, as the discrepancy between mental and chronological age increased, larger differences in scores were found.  相似文献   

Toward effective group formation in computer-supported collaborative learning     

Hamid Sadeghi 《Interactive Learning Environments》2016,24(3):382-395

Group formation task as a starting point for computer-supported collaborative learning plays a key role in achieving pedagogical goals. Various approaches have been reported in the literature to address this problem, but none have offered an optimal solution. In this research, an online learning environment was modeled as a weighted undirected complete graph in which each learner was implied as a node and the relationship between them was denoted as a weighted arc. The weight of each link indicated the similarity degree between the corresponding individuals. The similarity between two students was measured as the mean of their absolute interest levels. The graph was also represented through a symmetric adjacency matrix. Then, a novel binary integer programming formulation was proposed to model the group formation problem and optimally assign each learner to the most appropriate group. The method was utilized to divide an online class of 32 learners into 8 groups of size 4. Findings indicated that the suggested model was successful in optimally solving the problem in 20.53 seconds, on average. The performance of the method was also compared with a modified version of K-means clustering algorithm. Although, the running time of the suggested technique was not as good as the clustering algorithm, it generated better outcomes in theory and in practice.  相似文献   

`Emergency Education': The Missing Dimension in Education Policy     

Vijaya Sherry Chand  Samir Joshi  Ramji Dabhi 《Educational Research for Policy and Practice》2003,2(3):223-235

Large numbers of children regularly experience educational disruption because of natural disasters. Donor and rehabilitation agencies, using an ‘emergency education’ framework, have usually addressed the immediate needs of such children and longer-term educational reconstruction. However, the imperative of continuous educational access to all children, and the need for resource and curricular policies to deal with frequent disruption, call for the inclusion of an emergency education dimension in traditional educational policy. This article outlines the features of such a dimension by drawing on the experiences of an earthquake rehabilitation effort in India (2001-02). Policies that target an improved post-crisis educational system create an opportunity to redress past disadvantages. Helping local educational institutions build capacities in curriculum development and continuing education of emergency personnel is crucial. Some new features highlighted include tracking local demographic shifts with the help of local leaders and the use of innovative teachers to handle children’s immediate recreational needs. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

After Eighty Years: Experimental Study of Atmospheric Corrosion in the Metallic Dome of Hafez’s tomb,Shiraz, Iran     

Omid Oudbashi  Hamid Fadaei 《文物保护研究》2013,58(4):208-220

ABSTRACT

Hafez’s tomb was constructed on the grave of the well-known Iranian poet in Shiraz, in the 1930s. The dome of this monument is made of copper metal and has been exposed to the urban environment for 80 years. In this study, corrosion mechanisms and conservation conditions of the metallic dome of the Hafez’s tomb are investigated by analytical methods including optical microscopy, ICP-MS, SEM-EDX, and X-ray diffraction. The results showed that the dome is constructed from many copper sheets that are hammered to shape the dome. The corrosion products formed on the surface of copper sheets include copper oxide and copper trihydroxichlorides. In fact, the corrosion mechanism occurring in the metallic dome consists of copper oxidation and redeposition of copper II products because of reaction with air pollutants.  相似文献   

The Consequences of Information: Institutional Implications of Technological Change,by Jannis Kallinikos. Cheltenham,UK: Edward Elgar, 2006. $35.00 paper/$95.00 cloth. ISBN 978-1-84720-500-1 paper/978-1-84542-328-5 cloth     

Hamid R. Ekbia 《The Information Society》2013,29(2):121-122

Abstract

The U.S. Department of Agriculture has been mandated to “acquire and diffuse among the people of the United States useful information on subjects connected with agriculture in the most general and comprehensive sense of that word. …” With this authority the department has taken advantage of continuing advances of communications and computer technologies by initiating several programs related to the electronic dissemination of agricultural information. For example, the Foreign Agricultural Service has begun testing the release of agricultural trade leads through the University of Nebraska's AGNET computer‐based network. The Agricultural Marketing Service disseminates updated market data on more than 150 farm commodities over its leased wire market news network; the system has 140 terminals linked by some 14,500 miles of leased wires. Additional projects described in the article include a pilot project to deliver market news information to farmers via public television, programs testing the electronic marketing of livestock, and the electronic mail network operated by the department's Office of Governmental and Public Affairs.  相似文献