823 resultados para leader
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This paper reports a new strategy, recursive directional ligation by plasmid reconstruction (PRe-RDL), to rapidly clone highly repetitive polypeptides of any sequence and specified length over a large range of molecular weights. In a single cycle of PRe-RDL, two halves of a parent plasmid, each containing a copy of an oligomer, are ligated together, thereby dimerizing the oligomer and reconstituting a functional plasmid. This process is carried out recursively to assemble an oligomeric gene with the desired number of repeats. PRe-RDL has several unique features that stem from the use of type IIs restriction endonucleases: first, PRe-RDL is a seamless cloning method that leaves no extraneous nucleotides at the ligation junction. Because it uses type IIs endonucleases to ligate the two halves of the plasmid, PRe-RDL also addresses the major limitation of RDL in that it abolishes any restriction on the gene sequence that can be oligomerized. The reconstitution of a functional plasmid only upon successful ligation in PRe-RDL also addresses two other limitations of RDL: the significant background from self-ligation of the vector observed in RDL, and the decreased efficiency of ligation due to nonproductive circularization of the insert. PRe-RDL can also be used to assemble genes that encode different sequences in a predetermined order to encode block copolymers or append leader and trailer peptide sequences to the oligomerized gene.
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We report the observation with the North Alabama Lightning Mapping Array (LMA) related to a terrestrial gamma-ray flash (TGF) detected by RHESSI on 26 July 2008. The LMA data explicitly show the TGF was produced during the initial development of a compact intracloud (IC) lightning flash between a negative charge region centered at about 8.5 km above sea level (-22C temperature level) a higher positive region centered at 13 km, both confined to the convective core of an isolated storm in close proximity to the RHESSI footprint. After the occurrence of an LMA source with a high peak power (26 kW), the initial lightning evolution caused an unusually large IC current moment that became detectable 2 ms after the first LMA source and increased for another 2 ms, during which the burst of gamma-rays was produced. This slowly building current moment was most likely associated with the upward leader progression, which produced an uncommonly large IC charge moment change (+90 Ckm) in 3 ms while being punctuated by a sequence of fast discharge. These observations suggest that the leader development may be involved in the TGF production. Copyright © 2010 by the American Geophysical Union.
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The foraging activity of many organisms reveal strategic movement patterns, showing efficient use of spatially distributed resources. The underlying mechanisms behind these movement patterns, such as the use of spatial memory, are topics of considerable debate. To augment existing evidence of spatial memory use in primates, we generated movement patterns from simulated primate agents with simple sensory and behavioral capabilities. We developed agents representing various hypotheses of memory use, and compared the movement patterns of simulated groups to those of an observed group of red colobus monkeys (Procolobus rufomitratus), testing for: the effects of memory type (Euclidian or landmark based), amount of memory retention, and the effects of social rules in making foraging choices at the scale of the group (independent or leader led). Our results indicate that red colobus movement patterns fit best with simulated groups that have landmark based memory and a follow the leader foraging strategy. Comparisons between simulated agents revealed that social rules had the greatest impact on a group's step length, whereas the type of memory had the highest impact on a group's path tortuosity and cohesion. Using simulation studies as experimental trials to test theories of spatial memory use allows the development of insight into the behavioral mechanisms behind animal movement, developing case-specific results, as well as general results informing how changes to perception and behavior influence movement patterns.
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Research indicates that school leaders are crucial to improving instruction and raising student achievement (Council of Chief State School Officers, 2008). As such, educational reforms such as the No Child Left Behind Act (2001) and Race to the Top (2009) have sparked an accountability movement where principals are being held accountable for students' academic achievement and educational outcomes. The shift towards greater accountability has placed new attention on the ways principals are trained. Researchers have noted that organized professional development programs have not adequately prepared school principals to meet the priority demands of the 21st century (Hale & Moorman, 2003; Murphy, 1994). Murphy (1994) stated, "Traditional preparation programs - usually pre-service programs based in colleges or universities, that awarded certification and advanced degrees - rarely concentrated on the leadership challenges that principals actually face in real schools" (p. 4). As a result, many school districts are seeking ways to develop leadership development training programs that will prepare principals for their job responsibilities as a school leader. In spite of the additional training principals receive, researchers suggests that there is an obvious gap between the readiness of administrators to be instructional leaders and the demands for accountability that school administrators face (Hale & Moorman, 2003). This quantitative study examined elementary school principals' perceptions of their leadership development training program. Guided by four research questions, the study examined principals' perceptions of their overall training and how well their training prepared them to deal with school and classroom practices that contribute to student achievement; to work with teachers and others to design and implement a system for continuous student achievement; and to provide necessary support to carry out sound school, curriculum, and instructional practices. Data for this study was collected by way of survey responses from a total of 46 elementary school principals. The results from the study revealed that more than half (58.7%) of participants perceived their training as excellent. While principals' perceived that their training adequately prepared them to work collaboratively in teams, set clear visions and goals, and to use data to improve students achievement, many respondents reported a lack of training in being informed and focused on student achievement. Principals also suggested that they were not effectively trained in finding effective ways to obtain support from central office or community members.
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This article focuses on Keir Hardie's forgotten fiction and journalism for children, published in his paper The Labour Leader during the 1890s. It argues that Hardie's dialogue with child correspondents was shaped by a socialist periodical culture that redefined reading as a communal, political activity. Relating Hardie's appropriation of fantasy to that of a fellow socialist editor, John Trevor, the article examines the fairy tale as a propaganda tool in the process of `making socialists', but also questions the model of child readers as passive consumers, arguing that young readers were both empowered and controlled by Hardie's journalistic strategies.
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This research published in the foremost international journal in information theory and shows interplay between complex random matrix and multiantenna information theory. Dr T. Ratnarajah is leader in this area of research and his work has been contributed in the development of graduate curricula (course reader) in Massachusetts Institute of Technology (MIT), USA, By Professor Alan Edelman. The course name is "The Mathematics and Applications of Random Matrices", see http://web.mit.edu/18.338/www/projects.html
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One of the main pillars in the development of inclusive schools is the initial teacher training. Before determining if it is necessary to make changes (and of what type) in training programs or curriculum guides related to the attention to diversity and inclusive education, the attitudes of future education professionals in this area should be analyzed. This includes the identification of the relevant predictors of inclusive attitudes. The research reported in this article pursued this objective, doing so with a quantitative survey methodology based on the use of cross-sectional structured data collection and statistical analyses related to the quality of the attitude questionnaire (factor analysis and Cronbach's alpha), descriptive statistics, correlations, hypothesis tests for difference of means, and regression analysis in order to predict attitudes towards inclusion in education. Firstly, the results show that the participants held very positive attitudes toward the inclusion of students with special educational needs. Particularly, older respondents, those with a longer training and, to a lesser extent, women and those who had been in touch with disabled people stood out within this attitude. Secondly, it is evidenced that self-transcendence values and, more weakly, contact, function as robust predictors of attitudes of future practitioners towards the inclusion of students with special needs. Some applications for the initial professionalization of educators are suggested in the discussion.
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The order Nidovirales comprises viruses from the families Coronaviridae (genera Coronavirus and Torovirus), Roniviridae (genus Okavirus), and Arteriviridae (genus Arterivirus). In this study, we characterized White bream virus (WBV), a bacilliform plus-strand RNA virus isolated from fish. Analysis of the nucleotide sequence, organization, and expression of the 26.6-kb genome provided conclusive evidence for a phylogenetic relationship between WBV and nidoviruses. The polycistronic genome of WBV contains five open reading frames (ORFs), called ORF1a, -1b, -2, -3, and -4. In WBV-infected cells, three subgenomic RNAs expressing the structural proteins S, M, and N were identified. The subgenomic RNAs were revealed to share a 42-nucleotide, 5' leader sequence that is identical to the 5'-terminal genome sequence. The data suggest that a conserved nonanucleotide sequence, CA(G/A)CACUAC, located downstream of the leader and upstream of the structural protein genes acts as the core transcription-regulating sequence element in WBV. Like other nidoviruses with large genomes (>26 kb), WBV encodes in its ORF1b an extensive set of enzymes, including putative polymerase, helicase, ribose methyltransferase, exoribonuclease, and endoribonuclease activities. ORF1a encodes several membrane domains, a putative ADP-ribose 1"-phosphatase, and a chymotrypsin-like serine protease whose activity was established in this study. Comparative sequence analysis revealed that WBV represents a separate cluster of nidoviruses that significantly diverged from toroviruses and, even more, from coronaviruses, roniviruses, and arteriviruses. The study adds to the amazing diversity of nidoviruses and appeals for a more extensive characterization of nonmammalian nidoviruses to better understand the evolution of these largest known RNA viruses.
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With the impetus that has led recent studies on Latin American Modernism to a reevaluation of the sense of cultural fluxes from the modernity capitals to its peripheries –discarding categories such as “influence”, “exotism” and “ivory tower”, stereotypes that have clouded critical understanding of this aesthetics for decades- the present study intends to investigate a persistent practice of the main writers of the movement. This practice is modernist pictorial criticism, a genre that will be approached through the analysis of an unknown corpus: the seven chronicles Rubén Darío published in the journal La Prensa on occasion of the third art exposition of the Ateneo de Buenos Aires. Our hypothesis is that the rare creators of images portrayed by Darío by the end of 1895 work as a visual counterpoint of the eccentric writers’ biographical sketches that a year later will be part of the fundamental volume Los raros (1896). In this early “salon”, which we reproduce in its entirety, accompanied by explanatory notes, the leader of Modernism rehearses and consolidates his transcultural work with the universal tradition –now applied to the Salons (1845-1860) by Charles Baudelaire and to the monumental project by John Ruskin in Modern painters (1843-1860)- to legitimate, from another subgenre of Modernist criticism, a new figure of the critic, in dissent with the Enlightenment model of the writer.
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Cayetano tuvo un papel protagónico en los debates intelectuales de su época (s. XVI), destacándose como un auténtico adalid del tomismo; inclusive muchas de sus tesis pasaron a formar parte de tal doctrina, las cuales –a veces matizadas y otras no tanto– perviven hasta nuestros días. Entre los diversos temas que afrontó se destaca su particular noción de primum cognitum. Aquí, partimos del hecho de que la tradición tomista no ha visto mayores inconvenientes en equiparar lo que entienden Cayetano y el Aquinate por el ens primo cadit; empero nosotros estamos en condiciones de afirmar que tal equiparación al menos es problemática. En este sentido, nos ocuparemos de realizar un primer acercamiento al tema del ente primer conocido cayetaniano para intentar mostrar su real significado. Asimismo, procuraremos ver, ayudados por los aportes de algunos estudiosos contemporáneos –en especial el de Lawrence Dewan–, hasta qué punto tal noción se corresponde o no con los desarrollos teóricos de Tomás de Aquino, sobre todo con el vínculo entre el primer conocido y el ente como objeto de la metafísica.
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This article discusses the so-called newness of today's antisemitism through the historical and social specificities of antisemitism in French society. It casts light on the continuities of antisemitic discourse in France, but also its transformation in relation to the French colonial heritage and the recent ‘communitarianisation’ of France's social life. This analysis of antisemitism is furthered by the presentation of two case-studies: the controversial discourses of comedian Dieudonné and Kémi Séba, leader of a black supremacist movement called Tribu KA which stirred controversies in the 2000s. These two examples emphasise the fact that antisemitic discourse is better understood as a narrative about downward social mobility and status, which hardly makes antisemitism new.
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This article explores the various ways in which the Social Democratic and Labour Party (SDLP) has used Europe – as a source of financial aid, political support, ideas and inspiration – in its attempts to resolve the Northern Ireland conflict. In this, the piece considers the SDLP, not as a subject, but rather as an advocate of the Europeanization of the Northern Ireland problem. In particular, it looks at the role of John Hume, a founding member and later leader of the SDLP, who inculcated a strongly pro-European outlook within the party. In doing so, the article considers the success of Hume and the SDLP in their efforts to bring a European influence to bear on Northern Ireland, especially in relation to the peace process and the 1998 Agreement. However, it also looks at both the limitations of this influence, and the problems involved with the SDLP's pro-European approach, particularly since Hume's departure as party leader in 2001. In conclusion, the article suggests that the party may have been ‘over-Europeanized’, with its long-term focus on European issues and ideas now becoming electorally disadvantageous. In this way, the Europeanization of the Northern Ireland problem, and by extension the SDLP, has proven costly to the party.
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Despite the simultaneous progress of traffic modelling both on the macroscopic and microscopic front, recent works [E. Bourrel, J.B. Lessort, Mixing micro and macro representation of traffic flow: a hybrid model based on the LWR theory, Transport. Res. Rec. 1852 (2003) 193–200; D. Helbing, M. Treiber, Critical discussion of “synchronized flow”, Coop. Transport. Dyn. 1 (2002) 2.1–2.24; A. Hennecke, M. Treiber, D. Helbing, Macroscopic simulations of open systems and micro–macro link, in: D. Helbing, H.J. Herrmann, M. Schreckenberg, D.E. Wolf (Eds.), Traffic and Granular Flow ’99, Springer, Berlin, 2000, pp. 383–388] highlighted that one of the most promising way to simulate efficiently traffic flow on large road networks is a clever combination of both traffic representations: the hybrid modelling. Our focus in this paper is to propose two hybrid models for which the macroscopic (resp. mesoscopic) part is based on a class of second order model [A. Aw, M. Rascle, Resurection of second order models of traffic flow?, SIAM J. Appl. Math. 60 (2000) 916–938] whereas the microscopic part is a Follow-the Leader type model [D.C. Gazis, R. Herman, R.W. Rothery, Nonlinear follow-the-leader models of traffic flow, Oper. Res. 9 (1961) 545–567; R. Herman, I. Prigogine, Kinetic Theory of Vehicular Traffic, American Elsevier, New York, 1971]. For the first hybrid model, we define precisely the translation of boundary conditions at interfaces and for the second one we explain the synchronization processes. Furthermore, through some numerical simulations we show that the waves propagation is not disturbed and the mass is accurately conserved when passing from one traffic representation to another.
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Rural areas are recognised for their complex, multi-functional capacities with a range of different interest groups claiming their rights to, and use of, different rural spaces. The current rural development paradigm that is evident across the globe is epitomised by the European LEADER approach. Using evidence from the proposed National Park in Northern Ireland, we ask the question: what is the potential of sustainable rural tourism to contribute to rural development? Within our analysis we consider the scope for adaptive tourism to overcome some of the ongoing challenges that have been identified within the LEADER approach. Four themes are revealed from this analysis: institutional (in)capacity; legitimacy of local groups; navigating between stakeholder interests; and sustainable tourism in practice. These issues, discussed in turn, have clear implications for the new rural development programme.
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This article examines Africa's role in an evolving international system where powerful emerging markets, such as bric, together with established powers are shaping economic trajectories. The specific focus is on South Africa as an aspiring leader on the African continent, and on its potential for becoming an emerging market shaping the global order together with bric and the West. It is unclear whether a changing global economy in which the postcolonial world plays a greater role will result in improved developmental prospects for Africans as African countries gradually reorient themselves from the West to the South, or whether relations with emerging markets will resemble neo-colonial ties with the West. South Africa's structural weakness, stemming from serious domestic problems of a social, political and economic nature, threatens to undermine its standing in Africa and its emerging market status.