A formative analysis of individual differences in the effectiveness of learning objects in secondary school

The purpose of this study was to examine individual differences in the effectiveness of learning objects in secondary school classrooms. Specifically, gender, age, grade, subject area, and computer comfort (self-efficacy) were examined in 850 students. Effectiveness was measured in terms of student attitude (learning, quality, and engagement) and student performance. No gender differences were observed between males and females with respect to student attitudes or performance. Age was significantly correlated with student attitudes and performance, however correlation coefficients were small. Grade 12 students were more positive about learning objects and performed better than grade 9 and 10 students. Science students had significantly more positive attitudes and performed better than mathematics students. Finally, students who were more comfortable about computers, appreciated learning objects more than their less confident peers, however performance was unaffected.     

Low temperature synthesis and characterisation of lecontite, (NH4)Na(SO4)·2H20

Lecontite, (NH₄)Na(SO₄).2H₂O, was synthesised at room temperature in high purity compared to earlier work with a minor impurity of mascagnite, (NH₄)₂SO₄. Rietveld refinement of the XRD results confirmed the crystal structure and unit cell dimensions as published earlier. Raman and Infrared spectroscopy, in conjunction with factor group analysis, resulted in a complex pattern of overlapping sulphate, NH and OH modes. The NH modes υ₁ was observed around 2880 cm⁻¹, υ₂ around 1700 cm⁻¹ overlapping with water OH-bending modes, υ₃ around 3300 cm⁻¹ overlapping with water OH-stretching modes around 3023, 3185 and 3422 cm⁻¹, and υ₄ around 1432, 1447 and 1462 cm⁻¹. The sulphate group in the crystal structure displays a decrease in symmetry from T_d as evidenced by the activation of the ν₁ mode at 982 cm⁻¹ and the ν₂ mode around 452 cm⁻¹ in the Infrared spectrum. The υ₃ mode shows clear splitting in the infrared spectra with a strong band at 1064 cm⁻¹ accompanied by two shoulders at 1107 and 1139 cm⁻¹. The Raman spectra show three weak bands at 1068, 1109 and 1135 cm⁻¹ with a shoulder at 1155 cm⁻¹. Similar splitting was observed for the υ₄ mode around 611 and 632 cm⁻¹ in the Infrared and Raman spectra, respectively.     

Day Labourers, Unemployment and Socio-economic Development in South Africa

One of the most visible forms of unemployment is the men who stand at the side of the road or on corners daily, waiting for any job that may come their way. It is estimated that there are nearly 1,000 places in South Africa where a minimum of about 45,000, mostly black African men, stand, waiting to be picked up. The South African space economy is characterised by an uneven distribution of economic activities. International empirical studies have shown that there is a geographical or spatial coincidence between levels of unemployment and levels of gross domestic product per capita. The first objective of this article is to highlight some of the basic demographic dynamics of day labourers. The second is to investigate the spatial distribution of and the relationship between day labourers, unemployment and the general level of socio-economic development in South Africa. Day labourers share a number of common characteristics, but there were also obvious differences in their morale and spirit. The analyses showed that there is also a general spatial coincidence between levels of socio-economic development and the numbers of day labourers in South Africa, with a relatively high correlation coefficient between the two.     

Food insecurity in university students receiving financial aid.

PURPOSE: To evaluate the adequacy of loans funding and the risk for food insecurity in students living away from home and receiving loans at the University of Alberta. METHODS: A nutritious seven-day menu was developed. The menu was priced for skilled and unskilled shoppers at a grocery store near to campus and a discount-style grocery store further away. RESULTS: The menu was more costly for males, unskilled shoppers and those students who shopped near to campus. The menu cost was as high as $296/month and often exceeded the $196 allocated by the Canada Student Loans Program for food each month. CONCLUSIONS: Based on the findings from this study, students reliant on financial assistance likely have insufficient money for a nutritionally adequate diet and are at risk for food insecurity. Shopping skills and budgeting, while important, would be insufficient to alleviate food insecurity for many students who require financial aid. Increased funding for food in student loans is necessary.     

Continuous fuzzy conjunctions and disjunctions

Several functions have been used to implement conjunction and disjunction in fuzzy logic and to implement intersection and union in fuzzy set theory. Usually t-norms and t-conorms are used, but for some applications these may not be the best function classes. In this paper, I propose specific requirements which a function should satisfy if it is to be used to implement conjunction (or intersection) or disjunction (or union) and compare the functions proposed for conjunction to t-norms. In addition to stating basic properties of the resulting function classes, I give theorems on polynomial approximation within each class and on the existence of functions in either class with specified values at particular points     

Mycotoxin exposure and human cancer risk: A systematic review of epidemiological studies

In recent years, there has been an increasing interest in investigating the carcinogenicity of mycotoxins in humans. This systematic review aims to provide an overview of data linking exposure to different mycotoxins with human cancer risk. Publications (2019 and earlier) of case–control or longitudinal cohort studies were identified in PubMed and EMBASE. These articles were then screened by independent reviewers and their quality was assessed according to the Newcastle–Ottawa scale. Animal, cross‐sectional, and molecular studies satisfied criteria for exclusion. In total, 14 articles were included: 13 case–control studies and 1 longitudinal cohort study. Included articles focused on associations of mycotoxin exposure with primary liver, breast, and cervical cancer. Overall, a positive association between the consumption of aflatoxin‐contaminated foods and primary liver cancer risk was verified. Two case–control studies in Africa investigated the relationship between zearalenone and its metabolites and breast cancer risk, though conflicting results were reported. Two case–control studies investigated the association between hepatocellular carcinoma and fumonisin B1 exposure, but no significant associations were observed. This systematic review incorporates several clear observations of dose‐dependent associations between aflatoxins and liver cancer risk, in keeping with IARC Monograph conclusions. Only few human epidemiological studies investigated the associations between mycotoxin exposures and cancer risk. To close this gap, more in‐depth research is needed to unravel evidence for other common mycotoxins, such as deoxynivalenol and ochratoxin A. The link between mycotoxin exposures and cancer risk has mainly been established in experimental studies, and needs to be confirmed in human epidemiological studies to support the evidence‐based public health strategies.     

A Communicative Interdependence Perspective of Close Relationships: The Connections Between Mediated and Unmediated Interactions Matter

In response to calls to recognize that both face‐to‐face (FtF) interaction and technologically mediated communication (TMC) often occur in the same relationships, we introduce a communicative interdependence perspective with a central tenet that relational closeness is associated with interconnections among modes of communication. We examined this perspective with a focus group study (N = 17) and a more extensive survey (N = 317). Consistent with the communicative interdependence predictions, relational closeness was associated positively with integration between FtF and TMC and negatively to difficulties transitioning between modes. Also, discussing topics only via technologically mediated channels was inversely associated with closeness and satisfaction, whereas discussing topics only in person was positively related to closeness and satisfaction.     

Vitamin B1-Gehalt verschiedener Lebensmittel The thiamin-content of some foodstuffs

Zusammenfassung Es wird über den Vitamin B₁-Gehalt von verschiedenen Lebensmitteln berichtet. Es wird festgestellt, daß die papierchromatographisch ermittelten Werte häufig höher liegen als die entsprechenden Angaben in den gängigen Vitamin- bzw. Nährwerttabellen. Die Gründe werden erörtert.Es wird wahrscheinlich gemacht, daß der Mensch im Durchschnitt mehr Vitamin B₁ zu sich nimmt, als aus den Mittelwerten der in Deutschland bekannten Tabellen errechnet wird.

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Summary The thiamin-content of some foodstuffs is investigated. The contents, being determined by a method using paperchromatography, are often higher than those of the commonly used vitamin- or food-tables. The reasons are discussed.Probably, the average intake of thiamin is infact higher than the intake calculated from food-tables commonly used in Germany.

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Die Analysen wurden durchgeführt im Mag-Planck-Institut für Ernährungsphysiologie Dortmund. Damaliger Direktor: Prof. Dr. Dr. med. h. c. H. Kraut.