4,174 research outputs found
On hadron deformation: a model independent extraction of EMR from pion photoproduction data
The multipole content of pion photoproduction at the
resonance has been extracted from a data set dominated by recent Mainz
Microtron (MAMI) precision measurements. The analysis has been carried out in
the Athens Model Independent Analysis Scheme (AMIAS), thus eliminating any
model bias. The benchmark quantity for nucleon deformation, , was determined to be ,
thus reconfirming in a model independent way that the conjecture of baryon
deformation is valid. The derived multipole amplitudes provide stringent
constraints on QCD simulations and QCD inspired models striving to describe
hadronic structure. They are in good agreement with phenomenological models
which explicitly incorporate pionic degrees of freedom and with lattice QCD
calculations.Comment: 14 pages, 9 figures, 2 table
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Regulation of the cardiomyocyte transcriptome vs translatome by endothelin-1 and insulin: translational regulation of 5' terminal oligopyrimidine tract (TOP) mRNAs by insulin
Background: Changes in cellular phenotype result from underlying changes in mRNA transcription and translation. Endothelin-1 stimulates cardiomyocyte hypertrophy with associated changes in mRNA/protein expression and an increase in the rate of protein synthesis. Insulin also increases the rate of translation but does not promote overt cardiomyocyte hypertrophy. One mechanism of translational regulation is through 5' terminal oligopyrimidine tracts (TOPs) that, in response to growth stimuli, promote mRNA recruitment to polysomes for increased translation. TOP mRNAs include those encoding ribosomal proteins, but the full panoply remains to be established. Here, we used microarrays to compare the effects of endothelin-1 and insulin on the global transcriptome of neonatal rat cardiomyocytes, and on mRNA recruitment to polysomes (i.e. the translatome). Results: Globally, endothelin-1 and insulin (1 h) promoted >1.5-fold significant (false discovery rate 1.25-fold significant changes in expression in total and/or polysomal RNA induced by endothelin-1 or insulin, respectively, of which ~35% of endothelin-1-responsive and ~56% of insulin-responsive transcripts were translationally regulated. Of mRNAs for established proteins recruited to polysomes in response to insulin, 49 were known TOP mRNAs with a further 15 probable/possible TOP mRNAs, but 49 had no identifiable TOP sequences or other consistent features in the 5' untranslated region. Conclusions: Endothelin-1, rather than insulin, substantially affects global transcript expression to promote cardiomyocyte hypertrophy. Effects on RNA recruitment to polysomes are subtle, with differential effects of endothelin-1 and insulin on specific transcripts. Furthermore, although insulin promotes recruitment of TOP mRNAs to cardiomyocyte polysomes, not all recruited mRNAs are TOP mRNAs
Real principals in real multiethnic schools: the (im)possibilities for inclusive principal practice
Having as backdrop the immigration affecting educational processes in Greece and the rise of extreme-right groups, my thesis argues for the responsibility of principals to lead inclusive, egalitarian schools. Firstly, it demonstrates the importance of understanding the role of a school principal in an ethnically diverse school. Secondly, it argues for a genuine consideration of ethnocentrism and racism in the highly diversity-blind Greek education system. Examining ethnographically the everyday practices of three male principals in three multiethnic secondary schools in Greece, I draw on the theory of Pierre Bourdieu and the concepts of principal habitus, suggested by Lingard, Hayes, Mills and Christie, and institutional habitus, developed by Reay, Ball and David, to investigate the possibilities and impossibilities for principals to include immigrant students in the educational processes. Seeing principalship as a complicated and contextual practice, I interrogate principal practices at three levels: the vocational, the institutional and the classroom. My findings suggest that the administrative and pedagogical work of the principals has both a direct and indirect impact on the education of ethnic minority students. Exclusions of immigrant students occur through the ordinariness and mundanity of school administration. It is through this business-as-usual appearance that discrimination occurs, because it is misrecognised as such. Principal practices towards ethnic minority students appear as constellations of vocational, institutional and individual dispositions entangled in ethnocentric structures. Nonetheless, principals also practise disruptions to the exclusion of ethnic minority students. My findings question the role of agency to challenge the (im) possibilities for inclusive principal practice. Ultimately, the thesis argues for a principal role that is explicitly linked to social justice and that is given the tools for critical self-reflection that could turn impossible principalships for immigrant students into possible ones
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Glycogen synthase kinases 3α and 3β in cardiac myocytes: regulation and consequences of their inhibition
Inhibition of glycogen synthase kinase 3β (GSK3β) as a consequence of its phosphorylation by protein kinase B/Akt (PKB/Akt) has been implicated in cardiac myocyte hypertrophy in response to endothelin-1 or phenylephrine. We examined the regulation of GSK3α (which we show to constitute a significant proportion of the myocyte GSK3 pool) and GSK3β in cardiac myocytes. Although endothelin increases phosphorylation of GSK3 and decreases its activity, the response is less than that induced by insulin (which does not promote cardiac myocyte hypertrophy). GSK3 phosphorylation induced by endothelin requires signalling through the extracellular signal-regulated kinase 1/2 (ERK1/2) cascade and not the PKB/Akt pathway, whereas the reverse is true for insulin. Cardiac myocyte hypertrophy involves changes in morphology, and in gene and protein expression. The potent GSK3 inhibitor 1-azakenpaullone increases myocyte area as a consequence of increased cell length whereas phenylephrine increases both length and width. Azakenpaullone or insulin promotes AP1 transcription factor binding to an AP1 consensus oligonucleotide, but this was significantly less than that induced by endothelin and derived principally from increased binding of JunB protein, the expression of which was increased. Azakenpaullone promotes significant changes in gene expression (assessed by Affymetrix microarrays), but the overall response is less than with endothelin and there is little overlap between the genes identified. Thus, although GSK3 may contribute to cardiac myocyte hypertrophy in some respects (and presumably plays an important role in myocyte metabolism), it does not appear to contribute as significantly to the response induced by endothelin as has been maintained
Polymorphous heterogeneity and episodes of violence in school community: educational implications for building a democratic school
The present article is an attempt to shed light on a plethora of research studies concerning bullying and acts of violence within school settings. Furthermore, a basic aim of the chapter is to present different facets of school bullying. The presentation and interpretation of different theoretical approaches and the connection with the pro ile of different fragile community members aims to gain an understanding of bullying and victimization. Social and cultural heterogeneity seems to reinforce intimidating forms of aggression. Furthermore, the article emphasizes on suggestions that deal with the root causes of aggression, abuse and violence to help schools prevent and deal with this serious issue and become the nurturing learning environments and democratic school that they should be
Linguistic deficiencies in primary progressive multiple sclerosis
The aim of the present study is to investigate the linguistic profile of patients with Primary Progressive Multiple Sclerosis (PPMS) in relation to linguistic deficits associated with specific brain areas. Ten adults with PPMS were tested for the needs of the study and compared with healthy participants. The Boston Aphasia Naming Test, namely the tasks of listening comprehension, repetition, and reading comprehension, were administered. Results showed that the group of participants with PPMS had significantly lower performance in the above-mentioned tasks of comprehension compared to the control group. The findings are discussed
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Temporal regulation of expression of immediate early and second phase transcripts by endothelin-1 in cardiomyocytes
Background: Endothelin-1 stimulates Gq protein-coupled receptors to promote proliferation in dividing cells or hypertrophy in terminally differentiated cardiomyocytes. In cardiomyocytes, endothelin-1 rapidly (within minutes) stimulates protein kinase signaling, including extracellular-signal regulated kinases 1/2 (ERK1/2; though not ERK5), with phenotypic/physiological changes developing from approximately 12 h. Hypertrophy is associated with changes in mRNA/protein expression, presumably consequent to protein kinase signaling, but the connections between early, transient signaling events and developed hypertrophy are unknown. Results: Using microarrays, we defined the early transcriptional responses of neonatal rat cardiomyocytes to endothelin-1 over 4 h, differentiating between immediate early gene (IEG) and second phase RNAs with cycloheximide. IEGs exhibited differential temporal and transient regulation, with expression of second phase RNAs within 1 h. Of transcripts upregulated at 30 minutes encoding established proteins, 28 were inhibited >50% by U0126 (which inhibits ERK1/2/5 signaling), with 9 inhibited 25-50%. Expression of only four transcripts was not inhibited. At 1 h, most RNAs (approximately 67%) were equally changed in total and polysomal RNA with approximately 17% of transcripts increased to a greater extent in polysomes. Thus, changes in expression of most protein-coding RNAs should be reflected in protein synthesis. However, approximately 16% of transcripts were essentially excluded from the polysomes, including some protein-coding mRNAs, presumably inefficiently translated.
Conclusion: The phasic, temporal regulation of early transcriptional responses induced by endothelin-1 in cardiomyocytes indicates that, even in terminally differentiated cells, signals are propagated beyond the primary signaling pathways through transcriptional networks leading to phenotypic changes (that is, hypertrophy). Furthermore, ERK1/2 signaling plays a major role in this response
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