On the use of ASTM closed vessel tests in accelerated ageing research

The ASTM D6819-02e3 standard for testing the accelerated ageing of paper, published in 2002, recommends using closed glass vials in order to keep the degradation products in contact with the paper and thus permitting a better simulation of the natural ageing conditions inside closed books. In the present study, the actual conditions and their stability inside closed vessels have been evaluated. The necessity of assuring a very high sealing performance (tightness) of the systems in order to avoid leakage of water vapour is the main drawback of this ageing method. Systematic studies presented in this publication tried to monitor this tightness and have provided data that helped to answer the question of what circumstances could lead to achieving its improvement. Both gravimetric monitoring of water content in vials and “in situ” IR measurements of the aged paper humidity have been applied for this purpose. As a result, better sealing materials (gaskets and caps) than those recommended by the ASTM standard, have been found. Additionally, application of a dynamometric spanner for closing the vials is recommended, as this is a guarantee of reasonably high and recurring tightness of the systems used in tests. Nevertheless, the systematic, linear with time, loss of moisture for all used vials was observed. A 9% loss of the initial moisture content in samples of the aged paper was observed for the tested conditions (14 days at 90 °C). Therefore, it seems that including some kind of gravimetric control for ageing tests performed in closed vessels is of essential importance.Kinetic studies of accelerated ageing in both closed and open systems, as monitored by DP and breaking length measurements, unexpectedly show that no statistically meaningful difference of degradation rates can be observed. On the other hand, the pH and whiteness index values reveal a meaningful difference between the rates of ageing in these systems, thus confirming the basic assumption of the ASTM test concerning the interaction of paper degradation products with the paper itself.     

Post-collection acidification of spot urine sample is not needed before measurement of electrolytes

IntroductionKidney stone formers can have higher oxalate and phosphate salt amounts in their urine than healthy people and we hypothesized that its acidification may be useful. The study aims to compare results of urine concentrations of calcium, magnesium, and inorganic phosphorus in the midstream portion of first voided morning urine samples without (FMU) and with post-collection acidification (FMUa) in kidney stone patients.Materials and methodsThis is a prospective single center study. A total of 138 kidney stone patients with spot urine samples were included in the study. Urine concentrations of calcium, magnesium and inorganic phosphorus were measured with and without post-collection acidification. Acidification was performed by adding 5 µL of 6 mol/L HCl to 1 mL of urine.ResultsThe median age (range) of all participants was 56 (18-87) years. The median paired differences between FMU and FMUa concentrations of calcium, magnesium, and inorganic phosphorus were: - 0.040 mmol/L, 0.035 mmol/L, and 0.060 mmol/L, respectively. They were statistically different: P < 0.001, P < 0.001, P = 0.004, respectively. These differences are not clinically significant because biological variations of these markers are much higher.ConclusionsNo clinically significant differences in urinary calcium, magnesium, and inorganic phosphorus concentrations between FMU and FMUa in patients with kidney stones were found.     

A semantic differential investigation of children's attitudes toward three stigmatized groups

To test the assumption that negative attitudes toward various stigmatized groups are learned in early childhood, four scales of the semantic differential were employed to assess children's attitudes toward four groups (normals, crippled, retarded, and mentally ill) for both male and female third and sixth graders. The mentally ill were rated most negatively on both the Evaluation Scale and the Understandability Scale, but were rated comparable to normal people on Activity and Potency. Both the retarded and the crippled were rated less positively than normals on the Evaluation Scale, but not as negatively as the mentally ill. The retarded and the crippled were rated less Active and Potent than both normals and the mentally ill. No differences were found between the third and sixth graders on attitudes toward the three stigmatized groups. Implications for the “social labeling” theory of mental disorders are discussed.     

Diplomas for learning, not seat time: the impacts of New York Regents examinations

Economic theory predicts that improvements in signaling of achievement generated by external exit examination systems will (1) result in students learning more and this in turn will (2) enable them to get better paying jobs. Since New York State had the only statewide curriculum-based external exit exam system in the nation in the early 1990s, hypothesis 1 predicts that New York students should out perform socio-economically comparable students from other states. Cross section analysis of mean 8th grade NAEP math scores and SAT-I scores found that New York students were indeed about one grade level equivalent ahead of where one would expect given their socio-economic background. A similar analysis of dropout rate data found no differences between New York and other states. Hypothesis 2 was tested in HSB and NLS-88 data. Female students who reported that their high school required they pass a minimum competency exam in order to graduate were paid significantly more after they graduated from high school. Men did not earn more but did get a higher hourly wage.     

Warranted uncertainty and students' knowledge and use of drugs

The ability to recognize when it is warranted to be uncertain was developed effectively in 167 elementary school students through daily 15-min lessons over a 5-week period. This initial training did not deal with drug use in any way. A 3-year follow-up evaluation measured retention of these warranted-uncertainty skills, and assessed the effects of these skills on students' use of hard and soft drugs. In comparison with the matched control subjects, there was evidence of some retention after 3 years: the trained subjects were slightly better able to recognize when it is warranted to be uncertain about the effects of drugs. There was also strong evidence that many of the controls had acquired, somehow, the ability to generate warranted uncertainty, and that warranted uncertainty functioned as a stable construct (irrespective of how it was acquired) and was related to drug use. It appeared to produce a skepticism or an analytic attitude that allowed the student to ignore peer and parental dogma about drugs.