Quem são os Professores das Escolas Charter? Comparando Características dos Professores, Opções de Emprego e Preferências de Emprego

Given the importance of teachers to student learning, it is important to understand how and why charter schools differ in terms of their human capital. This paper explores the following questions: How do teacher qualifications and characteristics vary across school types? How much choice do teachers feel they have about where to work? How do teacher preferences for where to work differ by school type? Our findings suggest that charter school teachers do have different preferences for where to work compared to traditional public school teachers, but understanding these differences requires exploring differences among types of charter schools as well.Dada la importancia de los docentes en el aprendizaje de los estudiantes, es importante entender cómo y por qué las escuelas charter (concesionadas) difieren en cuanto a su capital humano (Brewer y Ahn, 2010). Este artículo explora las siguientes preguntas: ¿Cómo varían las cualificaciones y características de los docentes según los tipos de escuela? ¿Cuántas opciones de escoger tienen lo docentes sobre dónde trabajar?, ¿Cómo difieren las preferencias de los docentes sobre dónde trabajar según el tipo de escuela? Nuestros hallazgos sugieren que los docentes de escuelas charter tienen diferentes preferencias acerca de dónde trabajar en comparación con los maestros de escuelas públicas tradicionales, pero la comprensión de estas diferencias requiere también de explorar las diferencias entre los tipos de escuelas charter.Dada a importância dos professores para as aprendizagens dos estudantes, é importante compreender como e porquê as escolas Charter diferem em termos do seu capital humano (Brewer Ahn, 2010). Este artigo explora as seguintes questões: Como é que as qualificações e as características dos professores variam de acordo com o tipo de escola? Quanta possibilidade de escolha os professores sentem que têm sobre o local onde trabalhar? Como é que as preferências dos professores relativamente ao local onde trabalhar diferem com o tipo de escola? Os nossos resultados sugerem que os professores das escolas Charter têm diferentes preferências para o local de trabalho em comparação com os professores das escolas públicas tradicionais, mas a compreensão dessas diferenças exige explorar de igual modo as diferenças entre os tipos de escolas Charter

Integrating the geodesic equations in the Schwarzschild and Kerr space-times using Beltrami's "geometrical" method

We revisit a little known theorem due to Beltrami, through which the integration of the geodesic equations of a curved manifold is accomplished by a method which, even if inspired by the Hamilton-Jacobi method, is purely geometric. The application of this theorem to the Schwarzschild and Kerr metrics leads straightforwardly to the general solution of their geodesic equations. This way of dealing with the problem is, in our opinion, very much in keeping with the geometric spirit of general relativity. In fact, thanks to this theorem we can integrate the geodesic equations by a geometrical method and then verify that the classical conservation laws follow from these equations.Comment: 12 pages; corrected typos, journal-ref adde

A Semantic Web for bioinformatics: goals, tools, systems, applications

The quantity of biological information is increasing at an impressive rate. An integrated access to this huge amount of information requires complex search and retrieval software and automation of analysis processes. Automation of integration procedures mainly concerns how to link data, how to select and extract information and how to pipe retrieval and analysis steps. This automated approach to data analysis requires the adoption of new technologies and tools in the bioinformatics domain

SaDA: From Sampling to Data Analysis—An Extensible Open Source Infrastructure for Rapid, Robust and Automated Management and Analysis of Modern Ecological High-Throughput Microarray Data

One of the most crucial characteristics of day-to-day laboratory information management is the collection, storage and retrieval of information about research subjects and environmental or biomedical samples. An efficient link between sample data and experimental results is absolutely important for the successful outcome of a collaborative project. Currently available software solutions are largely limited to large scale, expensive commercial Laboratory Information Management Systems (LIMS). Acquiring such LIMS indeed can bring laboratory information management to a higher level, but most of the times this requires a sufficient investment of money, time and technical efforts. There is a clear need for a light weighted open source system which can easily be managed on local servers and handled by individual researchers. Here we present a software named SaDA for storing, retrieving and analyzing data originated from microorganism monitoring experiments. SaDA is fully integrated in the management of environmental samples, oligonucleotide sequences, microarray data and the subsequent downstream analysis procedures. It is simple and generic software, and can be extended and customized for various environmental and biomedical studies

Modello numerico in GRASS per la creazione di mappe di inondazione in caso di rottura di dighe

Dal 25 al 27 febbraio 2009 si è svolto a Cagliari il X Meeting degli utenti italiani GRASS e GFOSS. L'evento rappresenta da dieci anni l'occasione principale in cui tutta la comunità italiana, attiva nel campo dell'informazione geografica libera, si riunisce per confrontarsi e discutere sugli sviluppi futuri nel settore. Il meeting è stato organizzato dal CRS4 (Centro di Ricerca, Sviluppo e Studi Superiori in Sardegna), con il patrocinio dell'Università degli Studi di Cagliari, di Sardegna Ricerche e dell'associazione GFOSS.it. Gli obiettivi del X Meeting comprendono la presentazione delle innovazioni GFOSS nei seguenti campi: Sviluppi e personalizzazioni di software GIS liberi; Dati geografici liberi; GFOSS per la pubblica amministrazione; Formazione, divulgazione e sensibilizzazione nel campo del software libero; Interoperabilità e standard; Informazione geografica diffusa: web 2.0, GPS, LBS, etc ; Ambiente e territorio; Telerilevamento; Applicazioni di Geostatistica2009-02-26Facoltà di Ingegneria, Università degli Studi di Cagliari, Viale Merello, CagliariX Meeting degli utenti italiani GRASS e GFOS

Level densities of transitional Sm nuclei

Experimentally determined level densities of the transitional isotopes 148, 149, 150, 152Sm at excitation energies below and around the neutron binding energy are compared with microcanonical calculations based on a Monte Carlo approach to noncollective level densities, folded with a collective enhancement estimated in the frame of the interacting boson model (IBM). The IBM parameters are adjusted so as to reproduce the low-lying discrete levels of both parities, with the exception of the odd-mass nucleus, 149Sm, where complete decoupling of the unpaired neutron from the core is assumed

Historical explosive activity of Mount Melbourne Volcanic Field (Antarctica) revealed by englacial tephra deposits

Five tephra layers named BRH1 to 5 were sampled in an ice cliff located on the north-eastern flank of Mount Melbourne (northern Victoria Land, Antarctica). The texture, componentry, mineralogy, and major and trace element compositions of glass shards have been used to characterize these layers. These properties suggest that they are primary fall deposits produced from discrete eruptions that experienced varying degrees of magma/water interaction. The major and trace element glass shard analyses on single glass shards indicate that Mount Melbourne Volcanic Field is the source of these tephra layers and the geochemical diversity highlights that the eruptions were fed by compositionally diverse melts that are interpreted to be from a complex magma system with a mafic melt remobilizing more evolved trachy-andesitic to trachytic magma pockets. Geochemical compositions, along with textural and mineralogical data, have allowed correlations between two of the englacial tephra and distal cryptotephra from Mount Melbourne, recovered within a marine sediment core in the Edisto Inlet (~ 280 km northeast of Mount Melbourne), and constrain the age of these englacial tephra layers to between the third and the fourth century CE. This work provides new evidence of the intense historical explosive activity of the Mount Melbourne Volcanic Field and better constrains the rates of volcanism in northern Victoria Land. These data grant new clues on the eruptive dynamics and tephra dispersal, and considerably expand the geochemical (major and trace elements) dataset available for the Mount Melbourne Volcanic Field. In the future, this will facilitate the precise identification of tephra layers from this volcanic source and will help define the temporal and spatial correlation between Antarctic records using tephra layers. Finally, this work also yields new valuable time-stratigraphic marker horizons for future dating, synchronization, and correlations of different palaeoenvironmental and palaeoclimatic records across large regions of Antarctica

Higher order photoprotection mutants reveal the importance of \u394pH-dependent photosynthesis-control in preventing light induced damage to both photosystem II and photosystem I

Although light is essential for photosynthesis, when in excess, it may damage the photosynthetic apparatus, leading to a phenomenon known as photoinhibition. Photoinhibition was thought as a light-induced damage to photosystem II; however, it is now clear that even photosystem I may become very vulnerable to light. One main characteristic of light induced damage to photosystem II (PSII) is the increased turnover of the reaction center protein, D1: when rate of degradation exceeds the rate of synthesis, loss of PSII activity is observed. With respect to photosystem I (PSI), an excess of electrons, instead of an excess of light, may be very dangerous. Plants possess a number of mechanisms able to prevent, or limit, such damages by safe thermal dissipation of light energy (non-photochemical quenching, NPQ), slowing-down of electron transfer through the intersystem transport chain (photosynthesis-control, PSC) in co-operation with the Proton Gradient Regulation (PGR) proteins, PGR5 and PGRL1, collectively called as short-term photoprotection mechanisms, and the redistribution of light between photosystems, called state transitions (responsible of fluorescence quenching at PSII, qT), is superimposed to these short term photoprotective mechanisms. In this manuscript we have generated a number of higher order mutants by crossing genotypes carrying defects in each of the short-term photoprotection mechanisms, with the final aim to obtain a direct comparison of their role and efficiency in photoprotection. We found that mutants carrying a defect in the \u394pH-dependent photosynthesis-control are characterized by photoinhibition of both photosystems, irrespectively of whether PSBS-dependent NPQ or state transitions defects were present or not in the same individual, demonstrating the primary role of PSC in photoprotection. Moreover, mutants with a limited capability to develop a strong PSBS-dependent NPQ, were characterized by a high turnover of the D1 protein and high values of Y(NO), which might reflect energy quenching processes occurring within the PSII reaction center

The trans-subclavian retrograde approach for transcatheter aortic valve replacement: Single-center experience

ObjectiveAortic valve disease is the most common acquired valvular heart disease in adults. With the increasing elderly population, the proportion of patients with symptomatic aortic stenosis who are unsuitable for conventional surgery is increasing. Transcatheter aortic valve implantation has rapidly gained credibility as a valuable alternative to surgery to treat these patients; however, they often have severe iliac-femoral arteriopathy, which renders the transfemoral approach unusable. We report our experience with the trans-subclavian approach for transcatheter aortic valve implantation using the CoreValve (Medtronic CV Luxembourg S.a.r.l.) in 6 patients.MethodsIn May 2008 to September 2009, 6 patients (mean age of 82 ± 5 years), with symptomatic aortic stenosis and no reasonable surgical option because of excessive risk, were excluded from percutaneous femoral CoreValve implantation because of iliac-femoral arteriopathy. These patients underwent transcatheter aortic valve implantation via the axillary artery. Procedures were performed by a combined team of cardiologists, cardiac surgeons, and anesthetists in the catheterization laboratory. The CoreValve 18F delivery system was introduced via the left subclavian artery in 6 patients, 1 with a patent left internal thoracic to left anterior descending artery graft.ResultsProcedural success was obtained in all patients, and the mean aortic gradient decreased 5 mm Hg or less immediately after valve deployment. One patient required implantation of a permanent pacemaker. One patient required a subclavian covered stent implantation to treat a postimplant artery dissection associated with difficult surgical hemostasis. One patient was discharged in good condition but died of pneumonia 40 days after the procedure. All patients were asymptomatic on discharge, with good mid-term prosthesis performance.ConclusionsTranscatheter aortic valve implantation via a surgical subclavian approach seems safe and feasible, offering a new option to treat select, inoperable, and high-risk patients with severe aortic stenosis and peripheral vasculopathy