Young children's causal inferences

We report 2 experiments that show a striking development between the ages of 3 and 4 years in children's ability to make causal inferences about sequences of events. The task in the first experiment was to work out what had caused the change to an object that started out as odd (noncanonical) in 1 way and ended up as odd in 2 ways--starting, for example, as a broken cup and ending as a wet and broken cup. When asked to choose the instrument that had caused the change, 3-year-olds often selected the instrument that could have caused the initial state (a hammer, in our example) and not the instrument that would produce the change. 4-year-olds hardly ever made this mistake. In the second experiment, the 3-year-olds were able to make the correct choice when the change was from a canonical to a noncanonical state (cup-wet cup) but had much more difficulty when the change was from noncanonical to canonical (wet cup-dry cup). The difference was much smaller in the older group. The first of these tasks can be solved simply on the basis of knowledge that a particular instrument can cause a particular effect without reference to the initial state. The second task requires attention to the differences between initial and final state. We conclude that the ability to make genuine causal inferences develops between the ages of 3 and 4 years.     

Analysis of SEVA TB ES-31 antigen specific immunoglobulins IgM, IgA and IgG in sera of sputum and culture positive pulmonary tuberculosis

Tuberculosis remains major health problem in India and developing countries Immunodiagnosis has important role in screening, diagnosis and management of tuberculosis. SEVA TB ES-31 antigen has shown potential in detecting tuberculous IgG antibody in earlier studies from our laboratory. In the present study we have analysedSEVA TB ES-31 antigen specific immunoglobulinsIgM, IgA and IgG in clinically and bacteriologically confirmed pulmonary tuberculosis cases to determine the usefulness of specific immunoglobulin class in the diagnosis of patients attending the hospital. Of the 30 cases of pulmonary tuberculosis 25 (83.3%) were positive for IgG, 19 (63.3%) for IgM and 16 (53.3%) for IgA. On combining IgG and IgM positivity, sensitivity was increased to 93.3%. While combining IgG and IgA positivity, sensitivity increased to 90%. However specificity was decreased to 66.6% and 70% for both of these combinations respectively. It could be envisaged from this study that IgG antibody detection against ES-31 antigen showed acceptable sensitivity (83.3%) and specificity (86.6%) compared to IgM or IgA alone or in combination. When immune responses were analysed according to degree of sputum positivity, IgG response was observed to be predominant in all grades, compared to IgM or IgA antibody. The addition of IgM or IgA as an adjunct test increases the sensitivity but at the cost of specificity. Hence the detection of IgG alone is more useful compared to IgM or IgA assay, in detecting tuberculosis disease cases coming to the hospital.     

Serum and urinary zinc in zinc miners and zinc smelters

Serum (200.6±64.8 mg/dl) and urinary zinc (1186.0±265.5 mg/l.) of zinc miners at Zawar were significantly higher as compared to zinc smelter workers (Serum 89.7±9.9. mg/dl; Urine 590.0±32.1 mg/l.). Debari and Udaipur residents (Serum 104.0±18.6 mg/dl; Urine 735.0±180.2 mg/l.). This was most likely attributable to higher dietary zinc intake by zinc miners due to higher zinc content of foodstuffs grown in Zawar areas as compared to Debari and Udaipur.     

Regional Distribution of Copper,Zinc and Iron in Brain of Wistar Rat Model for Non-Wilsonian Brain Copper Toxicosis

In previous studies, we have reported first in vivo evidence of copper deposition in the choroid plexus, cognitive impairments, astrocytes swelling (Alzheimer type II cells) and astrogliosis (increase in number of astrocytes), and degenerated neurons coupled with significant increase in the hippocampus copper and zinc content in copper-intoxicated Wistar rats. Nonetheless, hippocampus iron levels were not affected by chronic copper-intoxication. Notwithstanding information on distribution of copper, zinc and iron status in different regions of brain due to chronic copper exposure remains fragmentary. In continuation with our previous study, the aim of this study was to investigate the effects of intraperitoneally injected copper lactate (0.15 mg Cu/100 g body weight) daily for 90 days on copper, zinc and iron levels in different regions of the brain using atomic absorption spectrophotometry. Copper-intoxicated group showed significantly increased cortex, cerebellum and striatum copper content (76, 46.8 and 80.7 % increase, respectively) compared to control group. However, non-significant changes were observed for the zinc and iron content in cortex, cerebellum and striatum due to chronic copper exposure. In conclusion, the current study demonstrates that chronic copper toxicity causes differential copper buildup in cortex, cerebellum and striatum region of central nervous system of male Wistar rats; signifying the critical requirement to discretely evaluate the effect of copper neurotoxicity in different brain regions, and ensuing neuropathological and cognitive dysfunctions.     

Diagnostic and prognostic value of the urinary excretion of beta-aminoisobutyric acid in patients with urinary bladder cancer

Urinary excretion of beta-aminoisobutyric acid (BAIB), was determined in 28 active and 12 inactive bladder cancer patients. Mean excretion of BAIB was higher in active cancer patients-187.8 mg/24 hours whereas it was 120.4 mg/24 hours in inactive cancer patients. The increased BAIB excretion in both disease groups was independent of tumour stage. BAIB appears to be a useful diagnositic aid in the assessment of bladder cancer patients.     

Lipid peroxidation and glutathione peroxidase in ischemic heart disease

With the growing interest in the concept of free radicals in the pathogenesis of myocardial ischemia, it was thought worthwhile to study the changes in lipid peroxides and antioxidant enzyme glutathione peroxidase (GPx) in ischemic heart disease (IHD). The study was carried out on 76 patients of IHD-38 of acute myocardial infarction (AMI) and 38 of stable ischemic heart disease (SIDH). They were age and sex matched with 38 normal healthy controls. A significant increase (p<0.001) in lipid peroxides as malondialdehyde (MDA) (5.9±0.7 mmol/L) and a decrease in GPx (24.6±2.2 U/gmHb) was found in patients of AMI when compared with controls. There was no significant difference in these values in SIHD. Thus this study confirms the earlier findings that MDA and GPx are useful parameters in IHD and their magnitude is dependent on severity and/or duration of ischemia. We suggest that these tests would be of use in smaller institutions with limited facilities.     

A science need: Designing tasks to engage students in modeling complex data

In this information age, the capacity to perceive structure in data, model that structure, and make decisions regarding its implications is rapidly becoming the most important of the quantitative literacy skills. We build on Kaput’s belief in a Science of Need to motivate and direct the development of tasks and tools for engaging students in reasoning about data. A Science of Need embodies the utility value of mathematics, and engages students in seeing the importance of mathematics in both their current and their future lives. An extended example of the design of tasks that require students to generate, test, and revise models of complex data is used to illustrate the ways in which attention to the contributions of students can aid in the development of both useful and theoretically coherent models of mathematical understanding by researchers. Tools such as Fathom are shown as democratizing agents in making data modeling more expressive and intimate, aiding in the development of deeper and more applicable mathematical understanding.