Thermal Ecology of the Australian Agamid Pogona barbata

This study compares the thermal ecology of male bearded dragon lizards (Pogona barbata) from south-east Queensland across two seasons: summer (1994-1995) and autumn (1995). Seasonal patterns of body temperature (Tb) were explored in terms of changes in the physical properties of the thermal environment and thermoregulatory effort. To quantify thermoregulatory effort, we compared behavioral and physiological variables recorded for observed lizards with those estimated for a thermoconforming lizard. The study lizards' field Tbs varied seasonally (summer: grand daily mean (GDM) 34.6 +/- 0.6 degrees C, autumn: GDM 27.5 +/- 0.3 degrees C) as did maximum and minimum available operative temperatures (summer: GDM Tmax 42.1 +/- 1.7 degrees C, Tmin 32.2 +/- 1.0 degrees C, autumn: GDM Tmax 31.7 +/- 1.2 degrees C, Tmin 26.4 +/- 0.5 degrees C). Interestingly, the range of temperatures that lizards selected in a gradient (selected range) did not change seasonally. However, P. barbata thermoregulated more extensively and more accurately in summer than in autumn; lizards generally displayed behaviors affecting heat load nonrandomly in summer and randomly in autumn, leading to the GDM of the mean deviations of lizards' field Tbs from their selected ranges being only 2.1 +/- 0.5 degrees C in summer, compared to 4.4 +/- 0.5 degrees C in autumn. This seasonal difference was not a consequence of different heat availability in the two seasons, because the seasonally available ranges of operative temperatures rarely precluded lizards from attaining field Tbs within their selected range, should that have been the goal. Rather, thermal microhabitat distribution and social behavior appear to have had an important influence on seasonal levels of thermoregulatory effort

The Search for Invariance: Repeated Positive Testing Serves the Goals of Causal Learning

Positive testing is characteristic of exploratory behavior, yet it seems to be at odds with the aim of information seeking. After all, repeated demonstrations of one’s current hypothesis often produce the same evidence and fail to distinguish it from potential alternatives. Research on the development of scientific reasoning and adult rule learning have both documented and attempted to explain this behavior. The current chapter reviews this prior work and introduces a novel theoretical account—the Search for Invariance (SI) hypothesis—which suggests that producing multiple positive examples serves the goals of causal learning. This hypothesis draws on the interventionist framework of causal reasoning, which suggests that causal learners are concerned with the invariance of candidate hypotheses. In a probabilistic and interdependent causal world, our primary goal is to determine whether, and in what contexts, our causal hypotheses provide accurate foundations for inference and intervention—not to disconfirm their alternatives. By recognizing the central role of invariance in causal learning, the phenomenon of positive testing may be reinterpreted as a rational information-seeking strategy

Isotopic Variability of Mercury in Ore, Mine-Waste Calcine, and Leachates of Mine-Waste Calcine from Areas Mined for Mercury

The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that δ202Hg values relative to NIST 3133 of calcine (up to 1.52‰) in the Terlingua district, Texas, are as much as 3.24‰ heavier than cinnabar (−1.72‰) prior to retorting. In addition, δ202Hg values obtained from leachates of Terlingua district calcines are isotopically similar to, or as much as 1.17‰ heavier than associated calcines, most likely due to leaching of soluble, byproduct Hg compounds formed during ore retorting that are a minor component in the calcines. As a result of the large fractionation found between cinnabar and calcine, and because calcine is the dominant source of Hg contamination from the mines studied, δ202Hg values of calcine may be more environmentally important in these mined areas than the primary cinnabar ore. Measurement of the Hg isotopic composition of calcine is necessary when using Hg isotopes for tracing Hg sources from areas mined for Hg, especially mine water runoff

Design, development and validation of a model of problem solving for Egyptian Science classes

Educators and policymakers envision the future of education in Egypt as enabling learners to acquire scientific inquiry and problem-solving skills. In this article, we describe the validation of a model for problem solving and the design of instruments for evaluating new teaching methods in Egyptian science classes. The instruments were based on an established model for problem solving and were designed to assess seventh grade students’ problem solving, experimental strategy knowledge, achievement and motivation towards science. The test for assessing students’ knowledge has been developed based on the topic, density and buoyancy which will be taught in seventh grade in a later intervention study. The instruments were partly self-developed and partly adapted from newly performed studies on strategy knowledge and problem solving in Germany. All instruments were translated into Arabic; the translation process and quality control are described. In order to determine the quality of the instruments, 44 students in Egypt completed the questionnaires and tests. The study’s aim to develop and validate the instruments did require an ad hoc and typical sample which was drawn from an accessible population. Accordingly, the characteristics of the sample are described. Data were analysed according to the classical test theory, but to underpin the results, the instruments were additionally analysed using the even stronger Rasch model. The findings demonstrated the reliability of the items and aspects of validity. In addition, this study showed how test items can be successfully developed and adapted in an international study and applied in a different language

Cloning and Functional Analysis of FLJ20420: A Novel Transcription Factor for the BAG-1 Promoter

BAG-1 is an anti-apoptotic protein that interacts with a variety of cellular molecules to inhibit apoptosis. The mechanisms by which BAG-1 interacts with other proteins to inhibit apoptosis have been extensively explored. However, it is currently unknown how BAG-1 expression is regulated at the molecular level, especially in cancer cells. Here we reported to clone a novel down-regulated BAG-1 expression gene named FLJ20420 using hBAG-1 promoter as a probe to screen Human Hela 5′ cDNA library by Southernwestern blot. The FLJ20420 gene encodes a ∼26-kDa protein that is localized in both the cytoplasm and nucleus. We proved that FLJ20420 protein can specially bind hBAG-1 promoter region by EMSA in vivo and ChIP assay in vivo. Northern blot analysis revealed a low level of FLJ20420 transcriptional expression in normal human tissues (i.e., brain, placenta, lung, liver, kidney, pancreas and cervix), except for heart and skeletal muscles, which showed higher levels. Furthermore, enhanced FLJ20420 expression was observed in tumor cell lines (i.e., MDA468, BT-20, MCF-7, C33A, HeLa and Caski). Knockdown of endogenous FLJ20420 expression significantly increased BAG-1 expression in A549 and L9981 cells, and also significantly enhanced their sensitivity to cisplatin-induced apoptosis. A microarray assay of the FLJ20420 siRNA –transfectants showed altered expression of 505 known genes, including 272 upregulated and 233 downregulated genes. Finally, our gene array studies in lung cancer tissue samples revealed a significant increase in FLJ20420 expression in primary lung cancer relative to the paired normal lung tissue controls (p = 0.0006). The increased expression of FLJ20420 corresponded to a significant decrease in BAG-1 protein expression in the primary lung cancers, relative to the paired normal lung tissue controls (p = 0.0001). Taken together, our experiments suggest that FLJ20420 functions as a down-regulator of BAG-1 expression. Its abnormal expression may be involved in the oncogenesis of human malignancies such as lung cancer

Rationality as a Goal of Education

Abstract Those who believe education should involve more than learning facts often stress either (a) development or (b) thinking skills. A focus on development as a goal of education typically entails a conception of knowledge as organismic, holistic, and internally generated. In contrast, thinking skills programs commonly assume a mechanistic, reductionist perspective in which good thinking consists of some finite number of directly teachable skills. A conception of rationality as a goal of education is proposed that incorporates the complementary strengths and avoids the limitations of the developmental and thinking skills approaches. Rationality is defined as the self-reflective, intentional, and appropriate coordination and use of genuine reasons in generating and justifying beliefs and behavior. Philosophically, rationality is a justifiable goal of education, not only because it is a means to worthwhile ends but because it is an important end in itself and because it can be promoted via non-indoctrinative means. A psychological account of progressive rationality is provided that postulates continuing multiple interactions of (a) domain-specific developmental stages, (b) the learning of specific thinking skills, and (c) content-specific knowledge. Suggestions are made for fostering rationality at various educational levels. Finally, it is argued that the proposed conception of rationality as a goal of education complements and clarifies a variety of other educational goals

Release of oxidizing fluids in subduction zones recorded by iron isotope zonation in garnet

Subduction zones are key regions of chemical and mass transfer between the Earth’s surface and mantle. During subduction, oxidized material is carried into the mantle and large amounts of water are released due to the breakdown of hydrous minerals such as lawsonite. Dehydration accompanied by the release of oxidizing species may play a key role in controlling redox changes in the subducting slab and overlying mantle wedge. Here we present measurements of oxygen fugacity, using garnet–epidote oxybarometry, together with analyses of the stable iron isotope composition of zoned garnets from Sifnos, Greece. We find that the garnet interiors grew under relatively oxidized conditions whereas garnet rims record more reduced conditions. Garnet δ56Fe increases from core to rim as the system becomes more reduced. Thermodynamic analysis shows that this change from relatively oxidized to more reduced conditions occurred during lawsonite dehydration. We conclude that the garnets maintain a record of progressive dehydration and that the residual mineral assemblages within the slab became more reduced during progressive subduction-zone dehydration. This is consistent with the hypothesis that lawsonite dehydration accompanied by the release of oxidizing species, such as sulfate, plays an important and measurable role in the global redox budget and contributes to sub-arc mantle oxidation in subduction zones

Physiogenomic analysis of weight loss induced by dietary carbohydrate restriction

BACKGROUND: Diets that restrict carbohydrate (CHO) have proven to be a successful dietary treatment of obesity for many people, but the degree of weight loss varies across individuals. The extent to which genetic factors associate with the magnitude of weight loss induced by CHO restriction is unknown. We examined associations among polymorphisms in candidate genes and weight loss in order to understand the physiological factors influencing body weight responses to CHO restriction. METHODS: We screened for genetic associations with weight loss in 86 healthy adults who were instructed to restrict CHO to a level that induced a small level of ketosis (CHO ~10% of total energy). A total of 27 single nucleotide polymorphisms (SNPs) were selected from 15 candidate genes involved in fat digestion/metabolism, intracellular glucose metabolism, lipoprotein remodeling, and appetite regulation. Multiple linear regression was used to rank the SNPs according to probability of association, and the most significant associations were analyzed in greater detail. RESULTS: Mean weight loss was 6.4 kg. SNPs in the gastric lipase (LIPF), hepatic glycogen synthase (GYS2), cholesteryl ester transfer protein (CETP) and galanin (GAL) genes were significantly associated with weight loss. CONCLUSION: A strong association between weight loss induced by dietary CHO restriction and variability in genes regulating fat digestion, hepatic glucose metabolism, intravascular lipoprotein remodeling, and appetite were detected. These discoveries could provide clues to important physiologic adaptations underlying the body mass response to CHO restriction