Who Stays and Who Leaves? Findings from a Three-Part Study of Teacher Turnover in NYC Middle Schools

This paper synthesizes findings from the Research Alliance's investigation of teacher turnover in New York City's public middle schools. These years are widely recognized as a critical turning point for students, and the NYC Department of Education (DOE) is pursuing a range of middle school improvement initiatives. The stability of the middle school teaching force has the potential to facilitate or complicate these efforts, yet there have been few studies of the rates and patterns of teacher turnover in the City's middle schools.This study provides the most current, comprehensive look at middle school teacher turnover to date. Drawing on a range of data sources -- including DOE human resource records from the last decade, a survey of over 4,000 full-time middle school teachers, and in-depth case studies in four middle schools -- this paper examines how long middle school teachers remain in their schools, how long they intend to stay, and what predicts whether or not they leave. It also explores how various aspects of teachers' work environment may influence these decisions. Among the key findings: Among middle school teachers who entered their school during the last decade, more than half left that school within three years -- significantly higher than the rates seen for elementary and high school teachers. Of the teachers who leave, most exit the NYC public school system altogether, and only about 1 in 10 transition to another grade 6-8 school. The findings point to several strategies that may be useful for increasing middle school teachers' lengths of stay

Two negative randomized controlled trials in lupus: now what?

Recently, two large randomized controlled trials of distinct biologic therapies in systemic lupus erythematosus, B-cell depletion with rituximab and co-stimulatory blockade with CTLA4Ig (abatacept), failed to meet primary endpoints. Given the great need for new treatments in lupus, these results were met with disappointment and have left the rheumatology and immunology community searching for an explanation. Are these experimental agents ineffective in lupus or are there trial design issues or other considerations? In this commentary, we discuss our perspective on these results within the context of current understanding of the pathophysiology of lupus and the mechanism of action of biologic therapies

Kinetic description of avalanching systems

Avalanching systems are treated analytically using the renormalization group (in the self-organized-criticality regime) or mean-field approximation, respectively. The latter describes the state in terms of the mean number of active and passive sites, without addressing the inhomogeneity in their distribution. This paper goes one step further by proposing a kinetic description of avalanching systems making use of the distribution function for clusters of active sites. We illustrate application of the kinetic formalism to a model proposed for the description of the avalanching processes in the reconnecting current sheet of the Earth magnetosphere.Comment: 9 page

Autonomic Nervous System characterization in hyperbaric environments considering respiratory component and non-linear analysis of Heart Rate Variability

Objectives: an evaluation of Principal Dynamic Mode (PDM) and Orthogonal Subspace Projection (OSP) methods to characterize the Autonomic Nervous System (ANS) response in three different hyperbaric environments was performed. Methods: ECG signals were recorded in two different stages (baseline and immersion) in three different hyperbaric environments: (a) inside a hyperbaric chamber, (b) in a controlled sea immersion, (c) in a real reservoir immersion. Time-domain parameters were extracted from the RR series of the ECG. From the Heart Rate Variability signal (HRV), classic Power Spectral Density (PSD), PDM (a non-linear analysis of HRV which is able to separate sympathetic and parasympathetic activities) and OSP (an analysis of HRV which is able to extract the respiratory component) methods were used to assess the ANS response. Results: PDM and OSP parameters follows the same trend when compared to the PSD ones for the hyperbaric chamber dataset. Comparing the three hyperbaric scenarios, significant differences were found: i) heart rate decreased and RMSSD increased in the hyperbaric chamber and the controlled dive, but they had the opposite behavior during the uncontrolled dive; ii) power in the OSP respiratory component was lower than power in the OSP residual component in cases a and c; iii) PDM and OSP methods showed a significant increase in sympathetic activity during both dives, but parasympathetic activity increased only during the uncontrolled dive. Conclusions: PDM and OSP methods could be used as an alternative measurement of ANS response instead of the PSD method. OSP results indicate that most of the variation in the heart rate variability cannot be described by changes in the respiration, so changes in ANS response can be assigned to other factors. Time-domain parameters reflect vagal activation in the hyperbaric chamber and in the controlled dive because of the effect of pressure. In the uncontrolled dive, sympathetic activity seems to be dominant, due to the effects of other factors such as physical activity, the challenging environment, and the influence of breathing through the scuba mask during immersion. In sum, a careful description of the changes in all the possible factors that could affect the ANS response between baseline and immersion stages in hyperbaric environments is needed for better interpretation of the results

Executive summary of the joint position paper on renal denervation of the Cardiovascular and Interventional Radiological Society of Europe (CIRSE) and the European Society of Hypertension (ESH)

No abstract available

Acute renal failure in an AIDS patient on tenofovir: a case report

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Efecto del NaCl sobre los parámetros de crecimiento, rendimiento y calidad de la cebolla de bulbo (Allium cepa L.) bajo condiciones controladas

El experimento se realizó en el primer semestre de 2010 en los invernaderos de la Facultad de Agronomía, Universidad Nacional de Colombia, Bogotá, con temperatura y humedad relativa promedio de 21°C y 60%, respectivamente. Se evaluó el efecto de concentraciones crecientes en el agua de riego de 0, 30, 60 y 90 mM de NaCl (conductividad eléctrica de 0, 3, 6 y 9 ±0,2 dS m-1, respectivamente) sobre parámetros de crecimiento, rendimiento y calidad en cebolla de bulbo, var. Yellow Granex, en un diseño completamente aleatorizado con cuatro repeticiones. Los niveles salinos crecientes generaron un desarrollo precoz, expresado en acumulación rápida de materia seca (MS) en los primeros estados de crecimiento, teniendo implicaciones fisiológicas en el desarrollo del bulbo. Se presentaron diferencias significativas a partir de la etapa de desarrollo del bulbo para las variables altura, número de hojas y diámetro del pseudotallo de la planta. Asimismo, se registraron reducciones respecto al tratamiento control de 31%, 53% y 70% de MS total, 44%, 53% y 71% de MS de la parte aérea, 28%, 49% y 74% de MS del bulbo, 12%, 25% y 43% para el diámetro y 30%, 52% y 78% para el peso fresco del bulbo en los niveles crecientes de 30, 60 y 90 mM de NaCl, respectivamente. Los niveles salinos crecientes se relacionaron directamente con el aumento en los valores de sólidos solubles totales y disminución en el contenido de ácido pirúvico, lo que se tradujo en un sabor más dulce y menos pungente de los bulbos.Cebolla de bulbo-Cebolla japonesa

Time Domain Analysis of Plasma Turbulence Observed Upstream of a Quasi- Parallel Shock

This paper presents, for the first time, an analysis of space plasma turbulence based on the NARMAX system identification approach. Fundamental nonlinear processes in the low frequency turbulence observed in the terrestrial fore-shock by AMPTE UKS and AMPTE IRM satellites are studied using time-domain identification methods developed for nonlinear dynamical systems. It is shown, directly from the the experimental data, that the cubic nonlinearity has a significant influence on the dependence of the phase velocity upon the wave amplitude. I comparison with a previous frequency domain approach the present method requires only short data sets

Asteroseismology with the WIRE satellite. I. Combining Ground- and Space-based Photometry of the Delta Scuti Star Epsilon Cephei

We have analysed ground-based multi-colour Stromgren photometry and single-filter photometry from the star tracker on the WIRE satellite of the delta scuti star Epsilon Cephei. The ground-based data set consists of 16 nights of data collected over 164 days, while the satellite data are nearly continuous coverage of the star during 14 days. The spectral window and noise level of the satellite data are superior to the ground-based data and this data set is used to locate the frequencies. However, we can use the ground-based data to improve the accuracy of the frequencies due to the much longer time baseline. We detect 26 oscillation frequencies in the WIRE data set, but only some of these can be seen clearly in the ground-based data. We have used the multi-colour ground-based photometry to determine amplitude and phase differences in the Stromgren b-y colour and the y filter in an attempt to identify the radial degree of the oscillation frequencies. We conclude that the accuracies of the amplitudes and phases are not sufficient to constrain theoretical models of Epsilon Cephei. We find no evidence for rotational splitting or the large separation among the frequencies detected in the WIRE data set. To be able to identify oscillation frequencies in delta scuti stars with the method we have applied, it is crucial to obtain more complete coverage from multi-site campaigns with a long time baseline and in multiple filters. This is important when planning photometric and spectroscopic ground-based support for future satellite missions like COROT and KEPLER.Comment: 13 pages, 12 figures, 4 tables. Fig. 4 reduced in quality. Accepted by A&

Annotated catalogue of melastomataceae species of a humid forest at margin of the Cauca river (Chinchina, Caldas, Colombia)

En Colombia, Melastomataceae es altamente diversa y juega un importante papel ecológico en sus ecosistemas. Debido a su alta diversidad y la importancia de varias especies en el remanente boscoso conocido como "Los Bosques de La Esmeralda o Bosques del Embalse San Francisco", se realizó el inventario, descripción y clave taxonómica de las especies de Melastomataceae presentes en esta zona. Se registran 12 especies, distribuidas en seis géneros. Los géneros que predominaron fueron Miconia (6) y Clidemia (3). El hábito que predominó fue el arbustivo (50%), seguido por el hábito arbóreo y herbáceo (25% cada uno). El 83% de las especies producen frutos en baya. La mayoría de las especies presentan una amplia distribución, con excepción de Leandra mexicana, la cual se registraba únicamente en los departamentos de Antioquia y Magdalena y ahora en Caldas. Este catálogo servirá para el reconocimiento de las especies de Melastomataceae en la zona, lo cual es la base para el diseño de proyectos de conservación y restauración ecológica de los Bosques del Embalse San Francisco.Melastomataceae is highly diverse in Colombia and it plays an important ecological role in itsecosystems. Due to its high diversity and the importance of several species in the remant forest known as Los Bosques de La Esmeralda or Bosques del Embalse de San Francisco ,an inventory, description and taxonomic key of Melastomataceae species present in the zone was carried out. Twelve species are registered, distributed in six genera. The predominant genera were Miconia (6) and Clidemia (3). The predominant habit was shrubby (50%), followed by arboreal and herbaceous (25% each). In total, 83% of the species produce fruits in berry. Most species show a wide distribution, except for Leandra Mexicana, which was registered only in the departments of Antioquia and Magdalena and now in Caldas. This catalog will serve to recognize Melastomataceae species in the area, which is the basis for the design of conservation projects and ecological restoration in Bosques del Embalse San Francisco. Key words: Species list, Caldas, Colombia, Melastomataceae, humid forest