Study on arsenic level in ground water of Delhi using hydride generator accessory coupled with atomic absorption spectrophotometer

Surveillance of drinking water is essentially a health measure intended to protect the public from water borne diseases. Hydride generator accessory coupled with atomic absorption spectrophotometer was used to analyze arsenic level in 49 ground water samples collected from different areas of Delhi. Arsenic level in ground water samples was in the range of 0.0170 to 0.100 ppm (Mean-0.0431, Standard Deviation-0.0136, Std. error of Mean-0.00194) with minimum concentration at Raney Well No. 7 (0.0170 ppm) and maximum at Kotla Mubarak Pur (0.100 ppm). Arsenic containing sediments and percolation of chemicals into soil as the result of dumping of garbage rich in chemicals into open landfills could be the possible source of arsenic in ground water of Delhi. Extensive survey and continuous monitoring is required to be made to assess the magnitude of problem and earlier intervention.     

We Can Still Learn About Probability by Rolling Dice and Tossing Coins

Rolling dice and tossing coins can still be used to teach probability even if students know (or think they know) what happens in these experiments. This article considers many simple variations of these experiments which are interesting, potentially enjoyable and challenging. Using these variations can cause students (and teachers) to think again about the statistical issues involved – and learn in the process.     

Seeing with electrons

In this article we briefly review the application of electrons in the field of microscopy. Two types of microscopes are discussed, the electron microscope and the tunneling microscope. It is emphasized that in both the applications the electron behaves as a quantum mechanical object.     

Helping science methods students construct meaning from text

Conclusion The pursuit of meaning through reflection is an ultimate goal of teacher education. The reading reaction sheet strategy is one way to help methods students construct meaning about science teaching and learning, and is applicable to other college courses where considerable reading is expected. Furthermore, through instructor modeling (Kyle, Abell, & Shymansky, 1989; Yeany & Padilla, 1986), preservice teachers are more likely to employ techniques for reading in the content area in their own teaching. Thus the reading reaction sheet strategy illustrates the integration of research in reading, writing, and science education and its application to classroom practice.     

Smooth-pursuit eye movements in the newborn infant.

The capacity of newborn infants to smooth-pursuit eye movements in single-target tracking and in optokinetic nystagmus to a moving striped field was examined utilizing DC electrooculography. Smooth-pursuit movements were observed in all infants who were alert during testing, but they occupied less than 15% of viewing time during single-target tracking. The velocity of smooth-pursuit segments in single-target tracking increased linearly to a target velocity of 19 degrees/sec and deteriorated rapidly at faster speeds. No smooth pursuit occurred above 32 degrees/sec in single-target tracking. By contrast, optokinetic nystagmus was observed at all field velocities to 40 degrees/sec, but the speed of the mean slow component increased linearly to 25 degrees/sec and diminished above that field velocity. Infant optokinetic nystagmus differed strikingly from that of adults in that tonic ocular deviation was in the direction of field movement rather than away from it. This feature of neonatal optokinetic nystagmus is consistent with deficient foveal function and suggests that the relatively poor smooth-pursuit performance of newborns may be related to foveal immaturity.     

麦克玛斯特大学"问题学习法"

本文从麦克玛斯特大学“问题学习法”(problern-based learning)实施过程的各个方面：教育目标、教学安排、教学活动、教学评价、教学资源等方面介绍了PBL的教学过程，总结了麦克玛斯特大学PBL课程设置以学生为本，培养学生的学习态度和终身学习的能力以及在教学过程中倡导以生物—心理—社会医学模式培养适合社会发展需要的医生的经验。     

The battered-child syndrome

The battered-child syndrome, a clinical condition in young children who have received serious physical abuse, is a frequent cause of permanent injury or death. The syndrome should be considered in any child exhibiting evidence of fracture of any bone, subdural hematoma, failure to thrive, soft tissue swellings or skin bruising, in any child who dies suddenly, or where the degree and type of injury is at variance with the history given regarding the occurrence of the trauma. Psychiatric factors are probably of prime importance in the pathogenesis of the disorder, but knowledge of these factors is limited. Physicians have a duty and responsibility to the child to require a full evaluation of the problem and to guarantee that no expected repetition of trauma will be permitted to occur.     

Naming-speed processes, timing, and reading: a conceptual review

This article integrates the findings in the special issue with a comprehensive review of the evidence for seven central questions about the role of naming-speed deficits in developmental reading disabilities. Cross-sectional, longitudinal, and cross-linguistic research on naming-speed processes, timing processes, and reading is presented. An evolving model of visual naming illustrates areas of difference and areas of overlap between naming speed and phonology in their underlying requirements. Work in the cognitive neurosciences is used to explore two nonexclusive hypotheses about the putative links between naming speed and reading processes and about the sources of disruption that may cause subtypes of reading disabilities predicted by the double-deficit hypothesis. Finally, the implications of the work in this special issue for diagnosis and intervention are elaborated.