Epistemology and conceptual resources for the development of learning technologies

The issues raised by the design and development of technologies to enhance learning has led to a demand for an appropriate language and form of conceptualisation. However we are insufficiently familiar with the way in which different types of mediated tool use occur, to develop the theoretical models needed for the development of this language and form of conceptualisation. In its absence a somewhat eclectic variety of concepts and research, such as the concept of affordance, are recruited in accounts of learning with new technologies. In looking briefly at the relevant area in philosophy this paper will consider whether or not the use of concepts such as affordance give adequate weight to social practice, meaning and knowledge in the design of educational technology. A fruitful source for work in this field which has not been sufficiently exploited is philosophy, particularly recent work in epistemology

Charged Condensation

We consider Bose-Einstein condensation of massive electrically charged scalars in a uniform background of charged fermions. We focus on the case when the scalar condensate screens the background charge, while the net charge of the system resides on its boundary surface. A distinctive signature of this substance is that the photon acquires a Lorentz-violating mass in the bulk of the condensate. Due to this mass, the transverse and longitudinal gauge modes propagate with different group velocities. We give qualitative arguments that at high enough densities and low temperatures a charged system of electrons and helium-4 nuclei, if held together by laboratory devices or by force of gravity, can form such a substance. We briefly discuss possible manifestations of the charged condensate in compact astrophysical objects.Comment: 1+11 pages; v2: comments and reference added, PLB versio

A Review on the Influence of Climate Change on Sheep Reproduction

Increasing food and natural fibre production ensure food security for nearly 10 billion people, the projected global population in 2050, without causing further environmental damage can be achieved by transforming systems and adopting sustainable agriculture practices within a changing climate. Globally, climate change effects are having both direct and indirect effects on agricultural productivity including changing rainfall patterns, drought, flooding and the geographical redistribution of pests and diseases. Climate change induced heat stress is thus one of the complex factors making sheep management and husbandry challenging in many geographical locations in the world. Within the sheep industry, reproductive wastage (RW) is a major challenge throughout the varying breeding landscapes. Reproductive wastage is defined as the early losses of embryos undergoing natural and/or artificial breeding programs. Our previous research showed that heat stress (THI > 75) and elevated glucocorticoid levels (indexed using faecal glucocorticoid metabolites) are linked to embryo loss in Merino ewes. This mini review discusses how extreme variation in climate such as heat stress affects the maternal reproductive performance in the Merino sheep and the impacts on the wool industry. We provide recommendations to sheep producers for monitoring and managing the effects of heat stress on-farm

Employer Health Benefits 2016 Annual Survey

This annual survey of employers provides a detailed look at trends in employer-sponsored health coverage including premiums, employee contributions, cost-sharing provisions, and employer opinions. The 2016 survey included almost 1,900 interviews with non-federal public and private firms.Annual premiums for employer-sponsored family health coverage reached $18,142 this year, up 3 percent from last year, with workers on average paying$5,277 towards the cost of their coverage, according to the Kaiser Family Foundation/Health Research & Education Trust 2016 Employer Health Benefits Survey. The 2016 survey includes information on the use of incentives for employer wellness programs, plan cost-sharing as well as firm offer rate. Survey results are released here in a variety of ways, including a full report with downloadable tables on a variety of topics, summary of findings, and an article published in the journal Health Affairs

Demonstration of the Feasibility of High Temperature Bearing Lubrication From Carbonaceous Gases

Research has been conducted on silicon nitride pin-on-disk sliding contacts at temperatures of up to 520 C, and four-ball rolling contacts with silicon nitride balls and 52100 steel or silicon nitride races at 590 C. These tests were conducted in a variety of gaseous environments in order to determine the effects of simulated engine exhaust gas on the carbonaceous gas decomposition lubrication scheme. In rolling tests with steel races and exhaust gas the wear track depth was roughly half that of tests run in nitrogen gas alone. The deposition of lubricous microcrystalline graphitic carbon on the rolling surfaces, generated from the carbon monoxide within the exhaust gas mixture, was verified by microfocused Raman spectroscopy. Ten-fold reductions in rolling wear could be achieved by the exhaust gas atmosphere in cases where water vapor was removed or not present. The exhaust gas mixture alone was not found to provide any lubricating effect on silicon nitride sliding contacts, where the rate of wear greatly exceeds the rate of carbon deposition. Directed admixture of acetylene (as low as 5% of the exhaust gas flow rates), has provided reductions in both wear volume and coefficient of friction by factors of 60X and 20X respectively for sliding contacts during the initial 80 m of sliding distance. Exhaust gas atmosphere with the acetylene admixture provided 65OX reductions in steady state wear rate compared to that measured for sliding contacts in dry N2. Such acetylene admixture also augments the ability of the exhaust gas atmosphere to lubricate high-temperature rolling contacts, with up to 25-fold reductions in wear track depth compared to those measured in the presence of N2 alone. In addition to providing some lubricating benefit itself, an important potential role of the exhaust gas from rich mixtures would be to shield bearings from 02. Such shielding enables surface deposition of lubricous pyrolytic carbon from the acetylene admixture, instead of combustion, rendering feasible the continuously replenished solid lubrication of high-temperature bearing surfaces

Self-reported sleep quality, weight status and depression in young adult twins and siblings

BACKGROUND: Research supporting relationships between sleep quality, weight, depression and anxiety has typically examined the relationships separately rather than simultaneously, potentially hampering insights into the characteristics of reported links. This study aimed to fill this gap in the research to provide further insight into the factors associated with sleep. METHODS: Data from wave 4 of the G1219 cohort were used in cross-sectional analyses. The sample comprised 1392 adult twins and siblings aged 18-27 years. Participants completed a self-report questionnaire which included the Pittsburgh Sleep Quality Index as a measure of sleep quality, the Short Mood and Feelings Questionnaire as a measure of depression symptoms and the Revised Symptoms of Anxiety Scale as a measure of anxiety symptoms. Participants were asked to self-report general health and weight and height so researchers could derive weight status from measures of body mass index. RESULTS: An analysis of covariance including weight status, depression, anxiety and general health as predictors and sleep quality as the outcome revealed main effects of depression (F(3,1163) = 10.93, p < 0.001) and general health (F(4,1163) = 5.72, p < 0.001) only. CONCLUSIONS: A direct relationship between weight and sleep should not be assumed as it is possible that the relationship is at least in part accounted for by depression symptoms or general health. Depression symptoms and general health may also account for the association between sleep quality and anxiety symptoms in young adults

Dna Profiling of Captive Roseate Spoonbill (Ajaia Ajaja) Populations As a Mechanism of Determining Lineage in Colonial Nesting Birds.

Roseate spoonbills are colonial nesting birds with breeding grounds extending from the United States Gulf coast to the pampas of Argentina. The U.S. population suffered a severe bottleneck from 1890 to 1920. The population's recovery was slow and partially credited to migrations from Mexican rookeries, but a gene pool reduction would be expected. Five polymorphic Spoonbill autosomal short tandem repeat (STR) loci [three (GAT)n, one (AAAG)n and one (GT)n] and one Z/W-linked microsatellite exhibiting sex-specific dimorphism were isolated and characterized. The Z/W-linked STR locus accurately confirmed the sex of each bird. Allelic profiles for 51 spoonbills obtained from Dallas (Texas), Fort Worth (Texas) and Sedgwick County (Kansas) zoos revealed a non-continuous distribution of allele frequencies, consistent with the effects of a population bottleneck. Allelic frequencies also differed significantly between the isolated zoo populations. Although extra-pair copulations were suspected and difficult to document, zoos commonly used observational studies of mating pairs to determine familial relationships among adults and offspring. STR parentage analysis of recorded family relationships excluded one or both parents in 10/25 cases studied and it was further possible to identify alternative likely parents in each case. Mistaken familial relationships quickly lead to the loss of genetic variability in captive populations. Here, a decreased heterozygosity (HO) in 2nd generation captive-bred birds was observed at 3 out of 4 loci evaluated. Although these results could not be statistically validated because of the small number of individuals available for study (15 wild birds with no offspring vs. eight 2nd generation captive birds), they are considered biologically important, as decreased HO is an indicator of inbreeding and this apparent decrease occurred within two generations of removal from the wild. Collectively, the evidence obtained from this study suggests that captive spoonbill populations are experiencing rapid loss of diversity from an already depleted wild gene pool

Rapid Evolution of BRCA1 and BRCA2 in Humans and Other Primates

The maintenance of chromosomal integrity is an essential task of every living organism and cellular repair mechanisms exist to guard against insults to DNA. Given the importance of this process, it is expected that DNA repair proteins would be evolutionarily conserved, exhibiting very minimal sequence change over time. However, BRCA1, an essential gene involved in DNA repair, has been reported to be evolving rapidly despite the fact that many protein-altering mutations within this gene convey a significantly elevated risk for breast and ovarian cancers. Results: To obtain a deeper understanding of the evolutionary trajectory of BRCA1, we analyzed complete BRCA1 gene sequences from 23 primate species. We show that specific amino acid sites have experienced repeated selection for amino acid replacement over primate evolution. This selection has been focused specifically on humans and our closest living relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). After examining BRCA1 polymorphisms in 7 bonobo, 44 chimpanzee, and 44 rhesus macaque (Macaca mulatta) individuals, we find considerable variation within each of these species and evidence for recent selection in chimpanzee populations. Finally, we also sequenced and analyzed BRCA2 from 24 primate species and find that this gene has also evolved under positive selection. Conclusions: While mutations leading to truncated forms of BRCA1 are clearly linked to cancer phenotypes in humans, there is also an underlying selective pressure in favor of amino acid-altering substitutions in this gene. A hypothesis where viruses are the drivers of this natural selection is discussed.National Institutes of Health R01-GM-093086, 8U42OD011197-13National Science Foundation BCS-07115972Burroughs Wellcome FundMolecular Bioscience

A Simple Method for Estimation of Agonist Activity at Receptor Subtypes: Comparison of Native and Cloned M3 Muscarinic Receptors in Guinea Pig Ileum and Transfected Cells

We describe a simple method for calculating the pharmacological activity of an agonist (A) relative to a standard agonist (S) using only the concentration-response curves of the two agonists. In most situations, we show that the product of the ratios of maximal responses (E max − A/E max − S) and potencies (EC50 − S/EC50 − A) is equivalent to the product of the affinity and intrinsic efficacy of A expressed relative to that of S. We refer to this term as the IRA value of A. In a cooperative system where the concentration-response curve of the standard agonist is steep and that of the test agonist is flatter with a lower maximal response, the simple calculation of IRA described above underestimates agonist activity; however, we also describe a means of correcting the IRA in this situation. We have validated our analysis with modeling techniques and have shown experimentally that the IRA values of muscarinic agonists for stimulating contractions in the guinea pig ileum (M3 response) are in excellent agreement with those measured in the phosphoinositide assay on Chinese hamster ovary cells expressing the M3 muscarinic receptor

Pre- and post-partum variation in wool cortisol and wool micron in Australian Merino ewe sheep (Ovis aries)

An individual merino sheep's output of wool production is influenced by synergistic interactions of sheep genetics, climate, farm management, and nutrition available to the whole flock. The price paid to the producer for this wool commodity is determined via numerous tested parameters and/or subjective appraisal of the raw greasy wool. This research investigated the level of variation in wool cortisol (a physiological stress biomarker) and wool micron (MIC) in Merino ewes (Ovis aries), pre-partum and post-lambing (lactation/lambs at foot), using maiden ewe (n = 38) managed in an outdoor paddock in a commercial farm. The key findings of this study are; (1) wool quality indicators showed a significant variation between pre- and post-parturition including significant reduction in MIC and (2) there was a negative correlation between wool cortisol levels and wool micron pre-parturition (rs = -0.179, p < 0.05). This relationship between wool cortisol and wool micron was positive (rs = +0.29, p < 0.05) during post-parturition suggesting that ewes with lambs at foot ended up with finer wool (reduction in fibre diameter) but they also maintained high levels of wool cortisol. Furthermore, the comfort factor, curvature, standard deviation and spin fineness of the wool were also significantly reduced post-parturition. The results of this study show that metabolic resources partitioning in ewe associated with pregnancy and lambing can result in a reduction in wool quality indices. The activity of the HPA-axis is attenuated during late gestation and parturition as a maternal adaptation; however, the results of our study show that wool cortisol remained similar between pre- and post-lambing. This result indicates that environmental stressors that may have been operating on farm (e.g., cold winter period) could influence on maternal physiological stress response however the exact level of influence of environment conditions on ewe stress levels and productivity traits (e.g., lambing success and wool quality) warrants further investigation. In conclusion, the use of top-knot wool sampling in combination with wool cortisol analysis provides researchers with a convenient method to quantify wool quality and physiological stress simultaneously under commercial sheep production