107 research outputs found
Student-Teachers\u27 Comments\u27 Type on Children\u27s Writing: Practices and Perceptions of their Role as Writing Facilitators
Student-Teachers\u27 Comments\u27 Type on Children\u27s Writing: Practices and Perceptions of their Role as Writing Facilitators
Abstract
This study examines how student-teachers in the final stage of their teacher education program, perceive the role of feedback and how they write feedback on children\u27s writing. Towards this end, student-teachers wrote compositions, answered a questionnaire, and wrote feedback on compositions written by 6th grade students. 10 student-teachers were also interviewed. Findings are that student-teachers perceive writing as a functional and technical process; they mainly edited the texts, they did not relate to the content, and were critical towards the expression of feelings and opinions in the children\u27s compositions. These findings contradict their stated preferred roles which are motivating students and promoting rewriting.
These results are discussed from two perspectives: the tension between ideal text concept and the purpose of writing feedback; and feedback writing as self-assessment tool in teacher education
Regulation of TNF-α by 1α,25-dihydroxyvitamin D3 in human macrophages from CAPD patients
Regulation of TNF-α by 1α,25-dihydroxyvitamin D3 in human macrophages from CAPD patients.BackgroundWe have previously reported that 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] accumulates in the dialysis fluid of uremic patients treated by continuous ambulatory peritoneal dialysis (CAPD). It has been reported that this metabolite regulates the production of cytokines by monocytes/macrophages. Since tumor necrosis factor-α (TNF-α) initiates an inflammatory cascade during peritonitis, the aim of the present study was to investigate the effect of 1α,25(OH)2D3 on the production of TNF-α by human peritoneal macrophages (HPMs).MethodsHPMs were obtained from patients on CAPD. Cells were incubated with various concentrations of 1α,25(OH)2D3, 1α,24(S) dihydroxyvitamin D2 [1α,24(S)(OH)2D2] or 25-hydroxyvitamin D3 (25-OH-D3) for 16 hours. This was followed by lipopolysaccharide (LPS; 1 μg/mL) incubation for 2.5 to 6 hours. TNF-α protein production was determined by enzyme-linked immunosorbent assay. TNF-α mRNA was assayed by the reverse transcriptase-polymerase chain reaction procedure, using internal synthetic mRNA standards for quantitative results.ResultsIncubation of HPMs with 1α,25(OH)2D3 prior to stimulation with LPS dose dependently inhibited the expression of TNF-α on both mRNA and protein levels. Similar results were obtained with the less calcemic vitamin D2 analogue 1α,24(S)(OH)2D2. Incubation of HPMs with 25-OH-D3 also revealed a down-regulation of TNF-α expression. Since this down-regulatory effect was blocked by ketoconazole, it is likely that this effect was caused by the conversion of 25-OH-D3 into 1α,25(OH)2D3 by HPMs.Conclusions1α,25(OH)2D3 has a potent inhibitory effect on the production of TNF-α by LPS-activated HPMs. We hypothesize that 1α,25(OH)2D3 may constitute a regulatory mechanism that, by controlling the intensity of the inflammatory response of the peritoneum, will moderate tissue damage during peritonitis
Associação Entre Estigma, dor e Qualidade de Vida em Mulheres com Cancro da Mama
Aim: We examined the association between cancer stigma and quality of life. We further explored the role of pain intensity in this association among women with breast cancer in the first months following diagnosis. Methods: 105 women with breast cancer within 8 months of diagnosis completed self-report measures assessing cancer stigma, pain intensity and quality of life. Results: Our findings show that stigma among breast cancer patients is associated with worse quality of life. Pain intensity partially mediated the relationship between cancer stigma and quality of life. We recruited a convenience sample of women with breast cancer, which may be subject to selection bias. The cross sectional design of the study precludes inferences regarding causality. Conclusions: Health professionals should recognize and mitigate the impact of stigma as an important factor that is associated with impaired quality of life among patients with breast cancer. Continued attention should be paid to pain intensity and the complex relationship between stigma and pain in predicting quality of life.Objetivo: O presente estudo procurou analisar a associação entre o estigma e a qualidade de vida em pessoas com cancro. Foi ainda explorado o papel da intensidade da dor nesta associação, em mulheres com cancro de mama, nos primeiros meses após o diagnóstico. Método: 105 mulheres com cancro da mama (até 8 meses após o diagnóstico) completaram medidas de autorrelato avaliando o estigma relacionado com o cancro, a intensidade da dor e a qualidade de vida. Resultados: Os nossos resultados mostram que o estigma entre pacientes com cancro de mama está associado a uma pior qualidade de vida. A intensidade da dor mediou parcialmente a relação entre o estigma relativo ao cancro e a qualidade de vida. Duas limitações são o facto de a amostra de mulheres com cancro da mama ser de conveniência, podendo ter estado sujeita a algum viés de seleção, e o facto de ser um estudo correlacional, que não permite inferências sobre causalidade. Conclusões: Os profissionais de saúde devem reconhecer e mitigar o impacto do estigma como um fator importante associado à diminuição da qualidade de vida de pacientes com cancro da mama. Deverá prestar-se atenção contínua à intensidade da dor e à complexa relação entre estigma e dor na previsão da qualidade de vida
Experience-Dependent Modulation of C. elegans Behavior by Ambient Oxygen
SummaryBackground: Ambient oxygen (O2) influences the behavior of organisms from bacteria to man. In C. elegans, an atypical O2 binding soluble guanylate cyclase (sGC), GCY-35, regulates O2 responses. However, how acute and chronic changes in O2 modify behavior is poorly understood.Results: Aggregating C. elegans strains can respond to a reduction in ambient O2 by a rapid, reversible, and graded inhibition of roaming behavior. This aerokinetic response is mediated by GCY-35 and GCY-36 sGCs, which appear to become activated as O2 levels drop and to depolarize the AQR, PQR, and URX neurons. Coexpression of GCY-35 and GCY-36 is sufficient to transform olfactory neurons into O2 sensors. Natural variation at the npr-1 neuropeptide receptor alters both food-sensing and O2-sensing circuits to reconfigure the salient features of the C. elegans environment. When cultivated in 1% O2 for a few hours, C. elegans reset their preferred ambient O2, seeking instead of avoiding 0%–5% O2. This plasticity involves reprogramming the AQR, PQR, and URX neurons.Conclusions: To navigate O2 gradients, C. elegans can modulate turning rates and speed of movement. Aerotaxis can be reprogrammed by experience or engineered artificially. We propose a model in which prolonged activation of the AQR, PQR, and URX neurons by low O2 switches on previously inactive O2 sensors. This enables aerotaxis to low O2 environments and may encode a “memory” of previous cultivation in low O2
Reconciling and Validating the Ashworth-Davies Doppler Shifts of a Translating Mirror
We simplify the Ashworth-Davies special relativistic theory of a uniformly
translating mirror with an arbitrary angle of incidence and direction of
propagation in the non-relativistic limit. We show that it is in good agreement
with a more intuitive derivation that only considers the constancy of the speed
of light. We confirm the theory with phase-insensitive frequency measurements
using a liquid crystal light valve
Light That Appears to Come from a Source That Does Not Exist
Superoscillatory, band-limited functions oscillate faster than their fastest Fourier component. Superoscillations have been intensively explored recently as they give rise to many out-of-the-spectrum phenomena entailing both fundamental and applied significance. We experimentally demonstrate a form of superoscillations which is manifested by light apparently coming from a source located far away from the actual one. These superoscillations are sensed through sharp transverse shifts in the local wave vector at the minima of a pinhole diffraction pattern. We call this phenomenon “optical ventriloquism.
Depolarization-Evoked Secretion Requires Two Vicinal Transmembrane Cysteines of Syntaxin 1A
BACKGROUND: The interactions of the voltage-gated Ca(2+) channel (VGCC) with syntaxin 1A (Sx 1A), Synaptosome-associated protein of 25 kD (SNAP-25), and synaptotagmin, couple electrical excitation to evoked secretion. Two vicinal Cys residues, Cys 271 and Cys 272 in the Sx 1A transmembrane domain, are highly conserved and participate in modulating channel kinetics. Each of the Sx1A Cys mutants, differently modify the kinetics of Cav1.2, and neuronal Cav2.2 calcium channel. METHODOLOGY/PRINCIPLE FINDINGS: We examined the effects of various Sx1A Cys mutants and the syntaxin isoforms 2, 3, and 4 each of which lack vicinal Cys residues, on evoked secretion, monitoring capacitance transients in a functional release assay. Membrane capacitance in Xenopus oocytes co-expressing Cav1.2, Sx1A, SNAP-25 and synaptotagmin, which is Bot C- and Bot A-sensitive, was elicited by a double 500 ms depolarizing pulse to 0 mV. The evoked-release was obliterated when a single Cys Sx1A mutant or either one of the Sx isoforms were substituted for Sx 1A, demonstrating the essential role of vicinal Cys residues in the depolarization mediated process. Protein expression and confocal imaging established the level of the mutated proteins in the cell and their targeting to the plasma membrane. CONCLUSIONS/SIGNIFICANCE: We propose a model whereby the two adjacent transmembranal Cys residues of Sx 1A, lash two calcium channels. Consistent with the necessity of a minimal fusion complex termed the excitosome, each Sx1A is in a complex with SNAP-25, Syt1, and the Ca(2+) channel. A Hill coefficient >2 imply that at least three excitosome complexes are required for generating a secreting hetero-oligomer protein complex. This working model suggests that a fusion pore that opens during membrane depolarization could be lined by alternating transmembrane segments of Sx1A and VGCC. The functional coupling of distinct amino acids of Sx 1A with VGCC appears to be essential for depolarization-evoked secretion
Enhancement of Naringenin Bioavailability by Complexation with Hydroxypropoyl-β-Cyclodextrin
The abundant flavonoid aglycone, naringenin, which is responsible for the bitter taste in grapefruits, has been shown to possess hypolipidemic and anti-inflammatory effects both in vitro and in vivo. Recently, our group demonstrated that naringenin inhibits hepatitis C virus (HCV) production, while others demonstrated its potential in the treatment of hyperlipidemia and diabetes. However, naringenin suffers from low oral bioavailability critically limiting its clinical potential. In this study, we demonstrate that the solubility of naringenin is enhanced by complexation with β-cyclodextrin, an FDA approved excipient. Hydroxypropoyl-β-cyclodextrin (HPβCD), specifically, increased the solubility of naringenin by over 400-fold, and its transport across a Caco-2 model of the gut epithelium by 11-fold. Complexation of naringenin with HPβCD increased its plasma concentrations when fed to rats, with AUC values increasing by 7.4-fold and Cmax increasing 14.6-fold. Moreover, when the complex was administered just prior to a meal it decreased VLDL levels by 42% and increased the rate of glucose clearance by 64% compared to naringenin alone. These effects correlated with increased expression of the PPAR co-activator, PGC1α in both liver and skeletal muscle. Histology and blood chemistry analysis indicated this route of administration was not associated with damage to the intestine, kidney, or liver. These results suggest that the complexation of naringenin with HPβCD is a viable option for the oral delivery of naringenin as a therapeutic entity with applications in the treatment of dyslipidemia, diabetes, and HCV infection.National Institute of Diabetes and Digestive and Kidney Diseases (U.S.) (K01DK080241)Harvard Clinical Nutrition Research Center (P30-DK040561)European Research Council (Starting Grant (TMIHCV 242699))Massachusetts General Hospital (BioMEMS Resource Center (P41 EB-002503))Alexander Silberman Institute of Life Science
Principles Of Heliophysics: a textbook on the universal processes behind planetary habitability
This textbook gives a perspective of heliophysics in a way that emphasizes
universal processes from a perspective that draws attention to what provides
Earth (and similar (exo-)planets) with a relatively stable setting in which
life as we know it can thrive. The book is intended for students in physical
sciences in later years of their university training and for beginning graduate
students in fields of solar, stellar, (exo-)planetary, and planetary-system
sciences.Comment: 419 pages, 119 figures, and 200 "activities" in the form of problems,
exercises, explorations, literature readings, and "what if" challenge
25th annual computational neuroscience meeting: CNS-2016
The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong
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