6,162 research outputs found
Reflection in work-based learning: self-regulation or self-liberation?
This article considers the role of reflective practice in work-based learning in higher education. The benefits of using reflection for learning at work have been widely recognised and the pedagogy to support reflection is now established. However, the use of reflective practice has been subjected to considerable critique, and many of the criticisms draw on Michel Foucault's concepts of governmentality, pastoral power, confession and self-regulation. Drawing on our professional experiences of supporting students in undertaking reflection, we examine the general critique put forward. Having considered the case that reflection supports self-regulation in a way which disadvantages individuals while benefiting organisations, we argue that reflection can be used to empower individuals. We do this by drawing attention to the elements of Foucault's argument which include the importance of agency in the exercise of power
Recent X-ray observations of intermediate BL Lac objects
We present recent ROSAT, ASCA and SAX observations of intermediate BL Lac
objects (IBLs), i.e. BL Lacs which are located between high-energy and
low-energy peaked BL Lac objects with respect to alpha_rx. Both the statistical
properties of IBLs from the RGB sample and a detailed broad band X-ray spectral
analysis of two objects (1424+2401, 1055+5644) point towards a continuous
distribution of synchrotron emission peak frequencies among BL Lac objects.Comment: 4 pages, 4 figures; to appear in the proceedings of the conference
"BL Lac Phenomenon" held in Turku, Finland, June 22-26, 199
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Bioaccumulation of PCB & DDE methyl sulfones in marine mammals and their interactions with receptor proteins
PCB and DDE-Methyl sulphone metabolites are the product of enzymatic and bile acid entero hepatic metabolism in the final phase (III) of PCB and DDE detoxification in mammals following hepatic microsomal cytochrome P450-dependent metabolism (phase I) and conjugation (phase II). There is good evidence that PCB and DDE methyl sulphone (MSF) metabolites interfere with steroid binding to a receptor protein in uterine epithelium (uteroglobin - UG2 and bronchial epithelium (clara cell secretory protein - CCSP). UG and CCSP are homologous 16,000 Da proteins with different tissue-specific functions. UG binds progesterone in the pre-implantation uterus to signal localised endometrial thickening and capillary formation, vital for successful attachment of the fertilised embryo. PCB-MSFs can displace progesterone in the mammalian uterus due to their higher affinity for UG, resulting in implantation failure or early fetal death. CCSP however, functions to sequester phospholipase A2 (PLA2) released in response to stress (pathogenic infection / injury) to suppress inflammatory responses triggered by PLA2 in bronchial epithelium. CCSP is also known as retinol-binding protein (RBP) transporting retinol (vit A) to target epithelia for a functional immune response*. Studies with Harbour Seals demonstrated displacement of retinol from RBP by hydroxy-PCB metabolites resulting in immunosuppression. PCB-MSFs have been shown to accumulate in clara cells and uterine epithelium in laboratory radioactive tracer studies and CCSP-knock out studies with mice. PCB and DDE -MSFs burdens have been found in marine mammals, suggesting they may be subject to reproductive and immuno-toxic effects of these metabolites. This study determines PCB and DDE-MSFs burdens in tissues (including lung & uterus) of Harbour Seal (Phoca vitulina) and Striped Dolphin (Stenella coeruleoalba) morbillivirus victims and characterises the marine mammalian UG/CCSP protein
A Search For Light Hydrides In The Envelopes Of Evolved Stars
Hydrides are important molecular constituents of the interstellar and circumstellar media, but there are still many questions regarding their variety and formation. In the envelopes of asymptotic giant branch and red supergiant stars, hydrides like silane \chem{SiH_4}, phosphine \chem{PH_3}, ammonia \chem{NH_3}, and water \chem{H_2O} are known to form, but have been observed in stark overabundance relative to predictions of chemical equilibrium models\footnote{Agundez et al., A\&A 637, A59 (2020)}. Diatomic hydrides (species with the form XH) are natural precursors to their more hydrogenated counterparts, and could therefore be crucial in constraining this puzzling chemistry. In this talk, I will present our search for the hydrides silicon monohydride (\chem{SiH}), phosphinidene (\chem{PH}), and iron hydride (\chem{FeH}) using the Stratospheric Observatory for Infrared Astronomy (SOFIA). We used the German Receiver for Astronomy at Terahertz Frequencies (GREAT) instrument to search for rotational emission lines of these molecules along the line of sight toward the chemically rich circumstellar envelopes of the evolved stars IRC+10216 and VY Canis Majoris. In these spectra we detected high-energy ro-vibrational lines from over a dozen molecules, though no significant emission from our target molecules was found. We derive upper limits on their abundances in each source, discuss how these findings influence our understanding of hydride chemistry in circumstellar envelopes, and outline the observational steps needed to further constrain this chemistry
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