Progressão continuada : por que a revisão dos ciclos?

O presente artigo pretende registrar e também esclarecer a redução havida na duração dos ciclos da progressão continuada, na rede pública do Estado de São Paulo. Desde 1997, a Secretaria Estadual de Educação adotou o regime de ciclos para o ensino fundamental, com quatro anos de duração. Em 2007, esses ciclos foram reduzidos e é essa alteração que aqui se pretende discutir.

O bullying no contexto escolar (2º e 3º ciclos) : um plano de intervenção e prevenção

“Violência entre pares” e “maus tratos entre iguais” são as expressões portuguesas mais utilizadas para definir o bullying. Independentemente do termo utilizado, a verdade é que estamos perante um fenómeno mundial crescente e alarmante entre os estudantes. A violência gerada nas escolas acarreta consequências graves nos jovens e mina o ambiente escolar. A complexidade do fenómeno bullying exige um esforço coletivo de prevenção e intervenção. Identificar o que está errado; conhecer os tipos de agressividade mais comuns; entender o tipo de relações entre pares; estreitar as relações com a família e desenvolver projetos de intervenção e prevenção na escola são os objetivos principais deste trabalho. Para analisarmos este fenómeno, começámos por realizar um inquérito em duas escolas da cidade de Lisboa com o intuito de saber quem são os intervenientes; que tipos de bullying são mais utilizados e com que frequência; se houve participação das agressões e possíveis consequências; qual o papel de cada um face ao bullying; se existem diferenças entre géneros e qual a imagem que os jovens têm de si próprios. A análise dos dados permitiu-nos concluir que este fenómeno existe e de uma forma bastante expressiva. Dos 192 estudantes inquiridos, apenas 36 não assumem qualquer papel, sendo que 13% dos jovens assumem-se como vítimas, 18,2% como agressores e 10,9% admitem ser, simultaneamente, vítimas e agressores. Por outro lado, 39,1% assume o papel de testemunha. Os tipos de violência mais praticados, segundo as vítimas, são mistos, isto é, violência física, psicológica e roubo ou quebra de objetos pessoais (24%). Quanto aos agressores, 40% assume que utiliza preferencialmente a violência psicológica em relação à física (25,7%). O recreio surge como o local onde a maioria das agressões acontece (44%). Quanto ao facto dos jovens fazerem, ou não, queixa, 56% dos jovens afirma que não faz e os que apresentam queixa consideram que não há qualquer consequência (72,7%). Assim, tornou-se evidente que deve haver uma intervenção eficaz no combate ao bullying. Para tal, elaborámos um plano de intervenção e prevenção, utilizando os recursos disponíveis e desenvolvendo ações em que todos os elementos da comunidade possam intervir. A direção da escola tem um papel fulcral neste projeto pois é a ela que cabe a gestão da escola e a possibilidade de permitir desenvolver as estratégias planeadas. Mas a complexidade do fenómeno bullying exige um esforço coletivo de prevenção e intervenção

Pago de potencia a través de opciones: perspectivas de aplicación al mercado eléctrico del Ecuador

En la actualidad los mercados de energía eléctrica pasan por una profunda reestructuración; especialmente en la creación de instrumentos para agilitar las transacciones y reducir el riesgo comercial entre los diferentes agentes del mercado eléctrico. El riesgo comercial, aparece debido a la disponibilidad de las unidades y centrales de generación que forman el sector eléctrico de manera especial el caudal de los ríos que alimentan a las centrales hidroeléctricas que poseen una elevada aleatoriedad. Esto hace que el sistema hidrotérmico presente precios muy volátiles los cuales dependan de la disponibilidad del parque generador. En las primeras etapas de la reestructuración todos los esfuerzos se han centrado en resolver los problemas particulares de cada mercado; de esa manera tender a la creación de mercados suficientemente líquidos y con una adecuada estructura competitiva, todo ello encaminado a garantizar que la oferta de energía se adecue a la demanda en todo momento, más las señales económicas para la oferta de generación; debe buscar ser estables y con mecanismos claros y transparentes para todos los agentes lo que permita la instalación de capacidad de potencia disponible en el sistema y con ello sea sustentable el sistema de una manera técnica, política como económicamente. Dichas características la presentan los mercados financieros específicamente las opciones. Para poder enfrentar estos inconvenientes presentes en el mercado, resulta útil analizar a otros mercados con características similares; el presente trabajo realiza el estudio del mercado de opciones para la remuneración de potencia aplicado al sector eléctrico y la aplicabilidad de esta metodología en Ecuador.

Pure water vapor continuum measurements between 3100 and 4400 cm1: Evidence for water dimer absorption in near atmospheric conditions

Despite the potentially important role that water dimers may play in the Earth’s energy balance, there is still a lack of firm evidence for absorption of radiation by dimers in near-atmospheric conditions. We present results of the first high-resolution laboratory measurements of the water vapor continuum absorption within the 3100–4400 cm1 spectral region at a range of near-room temperatures. The analysis indicates a large contribution of dimer absorption to the water vapor continuum, significantly in excess of that predicted by other modern representations of the continuum. The temperature dependence agrees well with that expected for dimers.

On the influence of stratospheric water vapor changes on the tropospheric circulation

Observations suggest that the mixing ratio of water vapour in the stratosphere has increased by 20–50% between the 1960s and mid-1990s. Here we show that inclusion of such a stratospheric water vapour (SWV) increase in a state-of-the-art climate model modifies the circulation of the extratropical troposphere: the modeled increase in the North Atlantic Oscillation (NAO) index is 40% of the observed increase in NAO index between 1965 and 1995, suggesting that if the SWV trend is real, it explains a significant fraction of the observed NAO trend. Our results imply that SWV changes provide a novel mechanism for communicating the effects of large tropical volcanic eruptions and ENSO events to the extratropical troposphere over timescales of a few years, which provides a mechanism for interannual climate predictability. Finally, we discuss our results in the context of regional climate change associated with changes in methane emissions.

Water vapor variability in the tropics and its links to dynamics and precipitation

The distribution and variability of water vapor and its links with radiative cooling and latent heating via precipitation are crucial to understanding feedbacks and processes operating within the climate system. Column-integrated water vapor (CWV) and additional variables from the European Centre for Medium-Range Weather Forecasts (ECMWF) 40-year reanalysis (ERA40) are utilized to quantify the spatial and temporal variability in tropical water vapor over the period 1979–2001. The moisture variability is partitioned between dynamical and thermodynamic influences and compared with variations in precipitation provided by the Climate Prediction Center Merged Analysis of Precipitation (CMAP) and the Global Precipitation Climatology Project (GPCP). The spatial distribution of CWV is strongly determined by thermodynamic constraints. Spatial variability in CWV is dominated by changes in the large-scale dynamics, in particular associated with the El Niño–Southern Oscillation (ENSO). Trends in CWV are also dominated by dynamics rather than thermodynamics over the period considered. However, increases in CWV associated with changes in temperature are significant over the equatorial east Pacific when analyzing interannual variability and over the north and northwest Pacific when analyzing trends. Significant positive trends in CWV tend to predominate over the oceans while negative trends in CWV are found over equatorial Africa and Brazil. Links between changes in CWV and vertical motion fields are identified over these regions and also the equatorial Atlantic. However, trends in precipitation are generally incoherent and show little association with the CWV trends. This may in part reflect the inadequacies of the precipitation data sets and reanalysis products when analyzing decadal variability. Though the dynamic component of CWV is a major factor in determining precipitation variability in the tropics, in some regions/seasons the thermodynamic component cancels its effect on precipitation variability.

A fast radiative transfer model for the assimilation of water vapor radiances from the Kalpana very high resolution radiometer

A fast radiative transfer model (RTM) to compute emitted infrared radiances for a very high resolution radiometer (VHRR), onboard the operational Indian geostationary satellite Kalpana has been developed and verified. This work is a step towards the assimilation of Kalpana water vapor (WV) radiances into numerical weather prediction models. The fast RTM uses a regression‐based approach to parameterize channel‐specific convolved level to space transmittances. A comparison between the fast RTM and the line‐by‐line RTM demonstrated that the fast RTM can simulate line‐by‐line radiances for the Kalpana WV channel to an accuracy better than the instrument noise, while offering more rapid radiance calculations. A comparison of clear sky radiances of the Kalpana WV channel with the ECMWF model first guess radiances is also presented, aiming to demonstrate the fast RTM performance with the real observations. In order to assimilate the radiances from Kalpana, a simple scheme for bias correction has been suggested.

Adsorption of water vapor by bare soil in an olive grove in southern Spain

Data for water vapor adsorption and evaporation are presented for a bare soil (sandy loam, clay content 15%) in a southern Spanish olive grove. Water losses and gains were measured using eight high-precision minilysimeters, placed around an olive tree, which had been irrigated until the soil reached field capacity (similar to 0.22 m(3) m(-3)). They were subsequently left to dry for 10 days. A pair of lysimeters was situated at each of the main points of the compass (N, E, S, W), at a distance of 1 m (the inner set of lysimeters; ILS) and 2 m (the outer set of lysimeters; OLS), respectively, from the tree trunk. Distinct periods of moisture loss (evaporation) and moisture gain (vapor adsorption) could be distinguished for each day. Vapor adsorption often started just after noon and generally lasted until the (early) evening. Values of up to 0.7 mm of adsorbed water per day were measured. Adsorption was generally largest for the OLS (up to 100% more on a daily basis), and increased during the dry down. This was mainly the result of lower OLS surface soil moisture contents (period-average absolute difference similar to 0.005 m(3) m(-3)), as illustrated using various analyses employing a set of micrometeorological equations describing the exchange of water vapor between bare soil and the atmosphere. These analyses also showed that the amount of water vapor adsorbed by soils is very sensitive to changes in atmospheric forcing and surface variables. The use of empirical equations to estimate vapor adsorption is therefore not recommended.

Evaluation of ozone and water vapor fields from the ECMWF reanalysis ERA-40 during 1991-1999 in comparison with UARS satellite and MOZAIC aircraft observations

[ 1] The European Centre for Medium-Range Weather Forecasts (ECMWF) 40-year Reanalysis (ERA-40) ozone and water vapor reanalysis fields during the 1990s have been compared with independent satellite data from the Halogen Occultation Experiment (HALOE) and Microwave Limb Sounder (MLS) instruments on board the Upper Atmosphere Research Satellite (UARS). In addition, ERA-40 has been compared with aircraft data from the Measurements of Ozone and Water Vapour by Airbus In-Service Aircraft (MOZAIC) program. Overall, in comparison with the values derived from the independent observations, the upper stratosphere in ERA-40 has about 5 - 10% more ozone and 15 - 20% less water vapor. This dry bias in the reanalysis appears to be global and extends into the middle stratosphere down to 40 hPa. Most of the discrepancies and seasonal variations between ERA-40 and the independent observations occur within the upper troposphere over the tropics and the lower stratosphere over the high latitudes. ERA-40 reproduces a weaker Antarctic ozone hole, and of less vertical extent, than the independent observations; values in the ozone maximum in the tropical stratosphere are lower for the reanalysis. ERA-40 mixing ratios of water vapor are considerably larger than those for MOZAIC, typically by 20% in the tropical upper troposphere, and they may exceed 60% in the lower stratosphere over high latitudes. The results imply that the Brewer-Dobson circulation in the ECMWF reanalysis system is too fast, as is also evidenced by deficiencies in the way ERA-40 reproduces the water vapor "tape recorder'' signal in the tropical stratosphere. Finally, the paper examines the biases and their temporal variation during the 1990s in the way ERA-40 compares to the independent observations. We also discuss how the evaluation results depend on the instrument used, as well as on the version of the data.

Assessment of the consistency of near-infrared water vapor line intensities using high-spectral-resolution ground-based Fourier transform measurements of solar radiation

Calculations of the absorption of solar radiation by atmospheric gases, and water vapor in particular, are dependent on the quality of databases of spectral line parameters. There has been increasing scrutiny of databases such as HITRAN in recent years, but this has mostly been performed on a band-by-band basis. We report nine high-spectral-resolution (0.03 cm(-1)) measurements of the solar radiation reaching the surface in southern England over the wave number range 2000 to 12,500 cm(-1) (0.8 to 5 mm) that allow a unique assessment of the consistency of the spectral line databases over this entire spectral region. The data are assessed in terms of the modeled water vapor column that is required to bring calculations and observations into agreement; for an entirely consistent database, this water vapor column should be constant with frequency. For the HITRAN01 database, the spread in water vapor column is about 11%, with distinct shifts between different spectral regions. The HITRAN04 database is in significantly better agreement (about 5% spread) in the completely updated 3000 to 8000 cm(-1) spectral region, but inconsistencies between individual spectral regions remain: for example, in the 8000 to 9500 cm(-1) spectral region, the results indicate an 18% (+/- 1%) underestimate in line intensities with respect to the 3000 to 8000 cm(-1) region. These measurements also indicate the impact of isotopic fractionation of water vapor in the 2500 to 2900 cm(-1) range, where HDO lines dominate over the lines of the most abundant isotope of H2O.

Laboratory measurements of the water vapor continuum in the 1200–8000 cm−1 region between 293 K and 351 K

Laboratory Fourier transform spectroscopy of pure water vapor and water vapor mixed with air has been conducted between 1200 and 8000 cm−1 and at temperatures between 293 and 351 K with the purpose of detecting and characterizing the water vapor continuum. The spectral features of the continuum within the major water absorption bands are presented and compared where possible to those from previous experimental studies and to the commonly used MT_CKD and CKD models. It was observed that in the main, both models adequately capture the general spectral form of the continuum; however, there were a number of exceptions. Overall, there is no evidence to indicate that MT_CKD is an improvement upon the older CKD model in these spectral regions. There was generally good agreement between our results and those of other experimental investigators. The general mathematical forms of the self-continuum temperature dependence, given by both Roberts et al. (1976) and CKD/MT_CKD, fit well to the experimental continuum in these spectral regions. However, the range of temperatures over which we made measurements is not sufficient to discriminate between these two forms or to exclude the possibility of other forms of temperature dependence being more appropriate. At the same time, the actual parameters currently used in CKD/MT_CKD to describe the temperature dependence in many spectral regions cannot reproduce the observed strong spectral variation in the temperature dependence. It has not been possible to make definitive conclusions about the magnitude of the continuum absorption in the far wings of the absorption bands investigated here.