Classroom contexts: Connections between class size and within class grouping

Background. There has been a vigorous debate for many years about the educational effects of class size differences, but even if differences have an impact on pupils' academic progress this still leaves unanswered important questions about what mediates the effect. Aims. This paper is informed by a classroom contextual perspective, and examines associations between class size and within class groupings (in terms of size and number of groups, adult presence in groups, and type of interaction between grouping members). Age differences in these relationships are also explored. Samples. The quantitative study is based on analysis of 3157 groupings, from 672 Reception, Year 2 and Year 5 classes in 331 schools. The qualitative study was based on 12 classes in 8 case study schools, and questionnaire responses completed by over 100 class teachers. Methods. Links between size of class and within class groupings were examined on the basis of a 'grouping mapping survey', in which teachers at a given time in the school day provided information on group size and number, adult presence, and type of interaction between pupils, and complementary qualitative analyses of data from teacher-completed questionnaires, and interviews. Results. The number of groups in a class increased with the size of the class. Over all three year groups, small classes had on average just over three groups, while large classes approached six groups. The size of groups in the class decreased with size of class. In class sizes over 25, pupils were more likely to be in a large group of 7-10, while in classes under 25 they were more likely to be in whole class groupings. Qualitative analyses showed that teachers felt that groups of 7-10 pupils had negative educational effects, for example, in terms of the quality and quantity of teaching and children's concentration and contribution in groups. Conclusions. Results suggest that the effects of class size can be best seen as through the size and number of groups, which will then have implications for learning experiences. So while debate about size of class has often been in terms of reduced size of class resulting in pupil academic gains, it is also important educationally to consider within class grouping size and number, and their effects.link_to_subscribed_fulltex

Past changes in riverine input and ocean circulation in the Gulf of Guinea

Large river systems draining the West African Monsoon area deliver sediments and dissolved trace elements into the Gulf of Guinea (GoG) in the easternmost equatorial Atlantic. The different catchment areas of these river systems are characterized by different geological ages and rock types releasing distinct radiogenic neodymium isotope compositions during weathering which are supplied to the GoG. The main rivers discharging into the GoG are the Niger, the Sanaga, the Nyong and the Ntem with present day εNd signatures of -10.5 [1], -12.3, -12.5 and -28.1 [2], respectively. These riverine inputs mix with the tropical Atlantic surface waters. At intermediate water depths Antarctic Intermediate Water (AAIW) prevails whereas the deep basin at this location is mainly filled with NADW. We focus on a marine sediment core that was recovered off the Sanaga and Ntem Rivers and we reconstruct changes in riverine inputs and in mixing of surface and deep water masses over the past 140,000 years. Changes in riverine inputs most likely reflecting latitudinal shifts of the rainfall zones across the different catchment areas were obtained from the Nd isotope signatures of the residual detrital fraction of the sediment. Sediment leachates of several GoG core top samples reflect the riverine input from nearby rivers indicating transport of particles coated in the rivers. Both the sediment leachates and the residual detrital fraction show similar patterns, with shifts towards radiogenic values during the interglacials and least radiogenic values during glacial periods. This shift in εNd values may be attributed to the migration of the rainfall zones towards the north during interglacial times and thus implies the increased influence of the northern rivers, the Sanaga and Nyong. The oxidatively-reductively cleaned planktonic foraminiferal calcite of the core top samples in the GoG reflects surface seawater signatures. Non-reductively cleaned planktonic foraminiferal tests and cleaned shallow endo-benthic and epi-benthic foraminiferal tests were used to acquire information about past bottom waters. Difficulties in cleaning down core foraminiferal samples were experienced and these samples appear to be contaminated by secondary manganese and iron bearing phases, even after cleaning. Those phases may have overprinted the original surface water Nd isotope composition in the planktonic foraminiferal tests. As the planktonic and benthic foraminiferal values are overall similar to the sediment leachates, the foraminiferal isotope signatures are most likely overprinted by isotopic signals originating from the rivers due to remobilization processes in the sediments and formation of secondary phases such as Mn-carbonates, which are attached to the foraminiferal calcites. References: [1] Goldstein et al. (1984) Earth and Planetary Science Letter 70, 221-236. [2] Weldeab et al. (2011) Geophysical Research Letter 38, pp. 5

Rare earth elements in Andaman Island surface water : geochemical tracers for the monsoon

The Asian summer monsoon affects the lives of billions of people. With the aim of identifying geochemical tracers for the monsoon related freshwater input from the major rivers draining into the Bay of Bengal and Andaman Sea we have taken surface seawater samples from various locations up and down the Andaman Islands during 2011. Importantly, in some locations samples have been taken in March, July and November, covering most of a seasonal cycle and different monsoon phases. Samples were collected from the side of small wooden boats or while swimming and were filtered within a few hours at 0.45 or 0.22 microns using the vacuum produced by a water jet or a hand operated peristaltic pump. Filtered and unfiltered samples were acidified to < pH 2 and analysed for Y and the REEs with an automated online preconcentration ICP-MS technique [1]. The local input of REEs from streams and sediment rich areas such as mangrove environments is clearly identified by middle REE enrichments in the shale normalised patterns of some samples. These middle REE bulges accompany large increases in dissolved REE concentrations at some locations, especially for the July samples obtained during the peak monsoon season with frequent storms. Y/Ho fractionation aslo occurs during the local input of dissolved REEs with affected samples having lower Y/Ho ratios. Conversly, some samples, in particular those taken after heavy rainfall in March, show strong REE scavenging accompanied by the prefferential removal of dissolved light REEs and higher Y/Ho ratios. The time series at a location away from local input sources shows remarkably similar REE patterns and concentraions in March and July. Then in October-November, following the peak in monsoon river discharge, the dissolved REE concentration increases by almost a factor of 2. The notable exception to this seasonal pattern is the Ce anomally which is around 0.3 in March and November but 0.6 in July, implying less oxidative removal of Ce(IV) during the peak summer monsoon rains. With the exception of elevated dissolved Ce concentrations, the North Pacific Deep Water normalised REE patterns are similar to those reported for offshore samples from the Bay of Bengal and Andaman Sea [2]. These seawater normalised patterns are distinctive having a middle REE enriched arc with similar light and heavy REE values suggesting the input from large rivers in the region is traceable using seawater REE chemistry. [1] Hathorne et al. (2012), Online preconcentration ICP-MS analysis of rare earth elements in seawater, Geochem. Geophys. Geosyst., 13, Q01020, doi:10.1029/2011GC003907. [2] Amakawa et al. (2000), Geochim. Cosmochim. Acta 64, 1715-1727

Extravehicular mobility unit subcritical liquid oxygen storage and supply system

The storage of life support oxygen in the Extravehicular Mobility Unit in the liquid state offers some advantages over the current method of storing the oxygen as a high pressure gas. Storage volume is reduced because of the increased density associated with liquid. The lower storage and operating pressures also reduce the potential for leakage or bursting of the storage tank. The potential for combustion resulting from adiabatic combustion of the gas within lines and components is substantially reduced. Design constraints on components are also relaxed due to the lower system pressures. A design study was performed to determine the requirements for a liquid storage system and prepare a conceptual design. The study involved four tasks. The first was to identify system operating requirements that influence or direct the design of the system. The second was to define candidate storage system concepts that could possibly satisfy the requirements. An evaluation and comparison of the candidate concepts was conducted in the third task. The fourth task was devoted to preparing a conceptual design of the recommended storage system and to evaluate concerns with integration of the concept into the EMU. The results are presented

Manejo del cáncer en atención primaria

408 p. : il.; gráf. , 22 cm.Libro ElectrónicoÍNDICE Índice de Autores Agradecimientos Prólogo La Oncología y el papel de A.Pen la prevención y seguimiento tumoral Félix Zubiri, Jesús Honorato y Wilson Astudillo Importancia de los programas de diagnóstico rápido en el cáncer de mama y colon Javier Zubeldia La Genética en el cáncer Iñaki Gutiérrez Iy Eunate Arana A Manifestaciones externas de las enfermedades oncológicas Anna Tuneu Vals y Arantxa López Pestaña Cáncer y sistema nerviosoTumores cerebrales primitivos y complicaciones neurológicas del cáncer Miguel AUrtasun Ocariz y José Félix Martí Massó Cáncer de pulmónPrevención, diagnóstico y tratamiento Yolanda Vilches A Novedades en el diagnóstico y tratamiento del cáncer de mama José Antonio Alberro Aduriz. Utilización de nanopartículas metálicas en el tratamiento de cánceres localizados Javier Aizpurua Iriazabal Cáncer de estómago y de intestino grueso: prevención y tratamiento Enrique Ojembarrena Martínez Posibilidades y límites de la cirugía en los tumores abdominales Adolfo Beguiristain Gómez El Hospital de Día y la hospitalización domiciliaria en el tratamiento onco- lógico y la paliación María Dolores De Damborenea González Tratamiento del dolor oncológico intenso Antonio Pernia Ry Luis Miguel Torres M. El cáncer en el niñoRealidad actual y expectativas Itziar Astigarraga Aguirre El niño con cáncer y los supervivientesLa superación de una nueva oportunidad Aurora Navajas Gutiérrez Organización de una unidad de Cuidados Paliativos pediátricos en la Comunidad de Madrid Ricardo Martino Alba, Ana Robles TElena Catá del Palacio, Carola del Rincón F El cáncer en el ancianoCaracterísticas y necesidades especiales Juan Carlos Caballero G. Necesidades emocionales en el paciente con cáncer Carmen Yélamos Ay Belén F Curados de cáncerLa superación y una nueva oportunidadLa necesidad de unidades especiales de apoyo Carmen Yélamos Ay José Samblas G El apoyo al cuidador del enfermo oncológico Wilson Astudillo A., Carmen Mendinueta Ay Beatriz Astudillo Ly Belén Díaz-Albo B Cuidados Paliativos en África Antonio Salinas-Martín y Emilio Montiano La limitación del esfuerzo terapéutico Carlos Romeo Casabona ¿Qué hacer cuando la curación no es posible? Papel de los Cuidados Paliativos Elías Díaz-Albo H., Belén Díaz-Albo B., Carmen Mendinueta Ay Wilson Astudillo A. Esperanza y dignidad en el paciente oncológico Koldo Martinez Urionabarrenetxea Sobre la felicidad y el sufrimiento Ramón Bayés Sopena Perspectiva de la OMS para el desarrollo de Cuidados Paliativos en el contexto de programa de control de cáncer en países en vías de desarrollo Cecilia Sepúlveda Bermedo Derechos de los cuidadores Derechos de un enfermo en el final de la vida Índice de materia