Project Coast: eugenics in apartheid South Africa     

Singh JA 《Endeavour》2008,32(1):5-9

It is a decade since the exposure of Project Coast, apartheid South Africa's covert chemical and biological warfare program. In that time, attention has been focused on several aspects of the program, particularly the production of narcotics and poisons for use against anti-apartheid activists and the proliferation of both chemical and biological weapons. The eugenic dimension of Project Coast has, by contrast, received scant attention. It is time to revisit the testimony that brought the suggestion of eugenic motives to light, reflect on some of the Truth and Reconciliation Commission's findings and search for lessons that can be taken from this troubled chapter in South Africa's history.  相似文献   

Using time-series analysis to predict disease counts with structural trend changes     

Amir Talaei-Khoei  James M. Wilson 《Information processing & management》2019,56(3):674-686

This paper aims at time-series prediction of disease counts when the trend changes unexpectedly. There is a body of literature in time-series analysis that focuses on improving the prediction when a change in the trend is observed. Following this line of literature, a method was recently proposed that outperforms the previous proposals. To utilize this method for prediction of disease counts, the present study employs a commonly used method called local estimators for estimation near boundaries. This provides two advantages for disease count prediction. First, the prior method is limited to only smooth trend changes. However, the current study using local estimators also encounters abrupt changes. Taking both smooth and abrupt changes into account is important in predicting disease counts, because, for variety of different reasons, such as vaccination programs, the disease counts may encounter abrupt changes. Second, the current study, despite the previous approach, can also model uncertainty. The parameter uncertainty plays a significant role when predicting disease counts. Compared to current literature, the proposed method outperformed to predict counts for 12 diseases in Nevada. The paper demonstrates that the proposed methods improved the prediction Q-Score in comparison to both outbreak and structural change methods available in literature. Although this method has been specifically demonstrated for prediction of disease counts, it can be generalized for different applications. With the recent utilization of analytics techniques and the increased use of time-series analysis in information systems, the suggested method provides implications for the literature of information systems when predicting with structural trend changes in data.  相似文献   

Experiencing equivalence but organizing order     

Amir H. Asghari 《Educational Studies in Mathematics》2009,71(3):219-234

The notion of equivalence relation is arguably one of the most fundamental ideas of mathematics. Accordingly, it plays an important role in teaching mathematics at all levels, whether explicitly or implicitly. Our success in introducing this notion for its own sake or as a means to teach other mathematical concepts, however, depends largely on our own conceptions of it. This paper considers various conceptions of equivalence, in history, in mathematics today, and in mathematics education. It reveals critical differences in the notion of equivalence at different points in history and a meaning for equivalence proposed by mathematicians and mathematics educators that is at variance with the ways that learners may think. These differences call into question the most popular view of the subject: that the mathematical notion of equivalence relation is the result of spelling out our experience of equivalence. Moreover, the findings of this study suggest that the standard definition of an equivalence relation is ill-chosen from a pedagogical point of view but well-crafted from a mathematical point of view.  相似文献   

High school students’ difficulties in understanding osmosis   总被引：1，自引：0，他引：1  

Yael Friedler  Ruth Amir  Pinchas Tamir 《International Journal of Science Education》2013,35(5):541-551

Preconceptions and misconceptions of 500 secondary students in years 9‐12 regarding osmosis were studied through the use of five different kinds of instruments: prior learning inventory, self‐report knowledge inventory, true/false test, definitions and clinical interviews. Some of the major findings were: (1) The most frequent explanation offered to osmosis is ‘a desire or drive towards equalizing concentrations’. (2) Hardly any student uses the concept ‘water concentration’. (3) Most students fail to realize that in dynamic equilibrium water molecules keep moving. (4) Students have special difficulty in understanding osmotic relations in plants. (5) Many students have difficulty in grasping solute‐solvent and concentration‐quantity relations. (6) Students often perform laboratory experiments without really understanding the underlying principles. Practical and theoretical implications are discussed.  相似文献   

The Spectrum of Dynamic Inquiry Teaching Practices     

Michal Zion  Smadar Cohen  Ruth Amir 《Research in Science Education》2007,37(4):423-447

The Israeli high school biology curriculum comprises the Biomind program, in which students are engaged in an open inquiry learning process. The dynamic features of open inquiry often pose challenges to teachers in implementing the Biomind program. The current qualitative research shows that facilitating students in a dynamic open inquiry process is multidimensional. Teaching practices cover a wide range of methods, from structured inquiry through guided inquiry to open inquiry. An individual teacher’s profile can be elucidated on the basis of this spectrum. In addition, we realised that teachers often encounter several difficulties in implementing open dynamic inquiry: A dearth of teachers’ scientific knowledge, students’ lack of scientific knowledge and skills, and a restrictive time-frame. This study suggests several areas which should be considered while implementing an on going professional development support for teachers who are engaged in open inquiry teaching.  相似文献   

Investigating the potential of using acoustic frequency on the degradation of linear alkylbenzen sulfonates from aqueous solution     

DEHGHANI Mohammad Hadi MAHVI Amir Hossein NAJAFPOOR Ali Asghar AZAM Kamal 《浙江大学学报(A卷英文版)》2007,8(9):1462-1468

The effectiveness of using acoustical (sonochemical) reactor for degradation of linear alkylbenzen sulfonate (LAS) from aqueous solution was investigated. LASs are anionic surfactants,found in relatively high amounts in domestic and industrial wastewaters. In this study,experiments on LAS solution were performed using methylene blue active substances (MBAS) method. The effectiveness of acoustical processor reactor for LAS degradation is evaluated with emphasis on the effect of treatment time and initial LAS concentration. Experiments were performed at initial concentrations of 0.2,0.5,0.8 and 1.0 mg/L,acoustic fre-quency of 130 kHz,applied power of 500 W and temperature of 18 °C～20 °C. At the conditions involved,LAS degradation was found to increase with increasing sonochemical time. In addition,as the concentration increased,the LAS degradation rate de-creased in the acoustical processor reactor.  相似文献   

Situational and personal influence on attitude change following ethnic contact     

Yehuda Amir  Chana Garti 《Int J Intercult Relat》1977,1(2):58-75

The study undertook to examine the validity in Israel of several conclusions reached by investigators in the United States on the effect of intergroup contact on change in ethnic attitudes, as well as to extend contact research to topics which heretofore have received only scant attention. There were 100 subjects: 12-year-old Israeli girls of different ethnic background, participating in a summer camp. Results indicated that (1) as a result of contact, a positive change in attitude of the high status towards the low-status group occurred with regard to people and activities both related and not related to the contact situation, (2) only subjects without previous ethnic contact showed changes, (3) enjoyment of the contact situation was related to attitude change, while (4) authoritarianism was not related to attitude change.  相似文献   

Threshold of Withdrawal from Schoolwork among Children of Divorced Parents     

Joseph Guttmann  Tova Amir  Michael Katz 《教育心理学》1987,7(4):295-302

Abstract The principal aim of the present study was to examine whether there is a difference of withdrawal threshold between children of divorced parents and children from intact families as regards schoolwork. Three different school‐type tests, designed to be long and frustrating, were administered to two groups of children. One group consisted of 31 children of divorced parents (15 boys and 16 girls); the second consisted of children from intact families and was of equal size and had a matching number of children of both sexes. There were three dependent variables: level of achievement, level of determination and the time spent on the test. The main results show that children of divorced parents have lower levels of achievement and lower withdrawal thresholds than do children from intact families. These findings are presented in the context of a consideration both of the children's experience and interpretation of their parents’ divorce and of the generalisability of the concept of withdrawal threshold.  相似文献   

An integrated group decision-making process for supplier selection and order allocation using multi-attribute utility theory and linear programming     

Amir Sanayei  S. Farid Mousavi  Ali Mohaghar 《Journal of The Franklin Institute》2008,345(7):731-747

Supplier selection is a complex multi-criteria problem including both quantitative and qualitative factors. In order to select the best suppliers it is necessary to make a trade-off between these factors, some of which may be in conflict and may also be uncertain. In this problem if suppliers have capacity or other different constraints, two problems will exist: which suppliers are best and how much should be purchased from each selected supplier.In this paper an integrated approach of multi-attribute utility theory (MAUT) and linear programming (LP) is proposed for rating and choosing the best suppliers and defining the optimum order quantities among selected ones in order to maximize total additive utility. A numerical example is proposed to illustrate an application of the proposed method.  相似文献   

Robust simultaneous fault detection and control for a class of nonlinear stochastic switched delay systems under asynchronous switching     

Hossein Shokouhi-Nejad  Amir Rikhtehgar Ghiasi  Mohammad Ali Badamchizadeh 《Journal of The Franklin Institute》2017,354(12):4801-4825

This paper concerns the simultaneous fault detection and control (SFDC) problem for a class of nonlinear stochastic switched systems with time-varying state delay and parameter uncertainties. The switching signal of detector/controller unit (DCU) is assumed to be with switching delay, which results in the asynchronous switching between the subsystems and DCU. By constructing a switching strategy depending on the state and switching delays, new sufficient conditions expressed by a set of linear matrix inequalities (LMIs) is derived to design DCU gains. This problem is formulated as an H_∞ optimization problem and both mean square exponential stability and fault detection of augmented system are considered. A numerical example is finally exploited to verify the effectiveness and potential of the achieved scheme.  相似文献