14 research outputs found
Origins of the Ambient Solar Wind: Implications for Space Weather
The Sun's outer atmosphere is heated to temperatures of millions of degrees,
and solar plasma flows out into interplanetary space at supersonic speeds. This
paper reviews our current understanding of these interrelated problems: coronal
heating and the acceleration of the ambient solar wind. We also discuss where
the community stands in its ability to forecast how variations in the solar
wind (i.e., fast and slow wind streams) impact the Earth. Although the last few
decades have seen significant progress in observations and modeling, we still
do not have a complete understanding of the relevant physical processes, nor do
we have a quantitatively precise census of which coronal structures contribute
to specific types of solar wind. Fast streams are known to be connected to the
central regions of large coronal holes. Slow streams, however, appear to come
from a wide range of sources, including streamers, pseudostreamers, coronal
loops, active regions, and coronal hole boundaries. Complicating our
understanding even more is the fact that processes such as turbulence,
stream-stream interactions, and Coulomb collisions can make it difficult to
unambiguously map a parcel measured at 1 AU back down to its coronal source. We
also review recent progress -- in theoretical modeling, observational data
analysis, and forecasting techniques that sit at the interface between data and
theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue
connected with a 2016 ISSI workshop on "The Scientific Foundations of Space
Weather." 44 pages, 9 figure
An Observational Overview of Solar Flares
We present an overview of solar flares and associated phenomena, drawing upon
a wide range of observational data primarily from the RHESSI era. Following an
introductory discussion and overview of the status of observational
capabilities, the article is split into topical sections which deal with
different areas of flare phenomena (footpoints and ribbons, coronal sources,
relationship to coronal mass ejections) and their interconnections. We also
discuss flare soft X-ray spectroscopy and the energetics of the process. The
emphasis is to describe the observations from multiple points of view, while
bearing in mind the models that link them to each other and to theory. The
present theoretical and observational understanding of solar flares is far from
complete, so we conclude with a brief discussion of models, and a list of
missing but important observations.Comment: This is an article for a monograph on the physics of solar flares,
inspired by RHESSI observations. The individual articles are to appear in
Space Science Reviews (2011
Effect of relaxin on semen quality variables of cryopreserved stallion semen
The aim of the study was to ascertain effects of different concentrations of relaxin added to extender medium during the pre-freezing incubation periods on quality variables of stallion frozen-thawed spermatozoa. Semen samples collected from three stallions were filtered, diluted with skim milk, and centrifuged at 600g for 10 min. Sperm pellets were suspended in BotuCrio freezing medium to a final concentration of 50
7 106 sperm/mL. The diluted semen was divided into five experimental groups supplemented with 0 (control), 12.5, 25, 50, or 100 ng/mL of relaxin. The semen samples were transferred into 0.5 mL straws, equilibrated at 5 \ub0C for 30 min, and placed in liquid nitrogen (LN2) vapour for 15 min before being plunged into LN2. After thawing, sperm samples were evaluated for motility and velocity variables, mitochondrial membrane potential, apoptosis, and plasma membrane and DNA integrities. For sperm motility variables, there were dose- and time-dependent effects, with the largest values recorded when 12.5 and 25 ng/mL relaxin were used for 0\u2013120 min of incubation. Furthermore, at all of the concentrations at which there were evaluations, relaxin additions to semen diluent led to a marked improvement in sperm mitochondrial membrane potential and a lesser percentage of apoptotic cells compared to the control group. Plasma membranes and DNA integrities were not affected by relaxin supplementations to the diluent. In conclusion, supplementation of relaxin in extender before semen cryopreservation, especially at 12.5 and 25 ng/mL, had a positive effect on the sperm quality variables
Activated carbon biochar from municipal waste as a sorptive agent for the removal of polyaromatic hydrocarbons (PAHs), phenols and petroleum based compounds in contaminated liquids
Wastewater (WW) sludge cake is problematic to dispose of with treatment unable to remove organic pollutants. Typical disposal options include landfill or deposition on agricultural land, at considerable expense and environmental impact. Pyrolysis can recycle this waste to biochar however, additional unwanted organic pollutants are generated, differing in composition and volume according to the feedstock. These pollutants can be captured in solvent impingers or ‘scrubbers’ to avoid environmental release but lead to alternative waste. Both activated carbon and biochar are proven clean-up methods for organic pollutants with pine wood biochar showing changes in extraction selectivity with preparation temperature. Activated carbon biochar (ACB) from pine wood has also been successfully compared as a substitute at reduced cost and improved efficacy. To our knowledge, ACB from sludge cake has remained untested along with its application to clean-up solvent scrubbers.We have investigated this material from two WW treatment plants (UK and Ghana) as a sorbent, generated at 400 and 700 °C, to minimise contamination of liquids from pyrolysis and, petrochemicals in the event of a spill. This study confirmed the use and selective production of ACB for preferential clean-up of specific pollutants.Despite high temperature pine wood ACB proving most effective in removing petrochemical mixtures (> 76%) extractions of equivalent repeatability and reasonable recovery were achieved with low temperature sludge cake ACB. This re-use of waste sludge cake offers improved thermochemical (recycling) and WW process efficiency, limiting the environmental impact and overall operational costs, minimising waste for disposal
Concepções de professores sobre inclusão escolar e interações em ambiente inclusivo: uma revisão da literatura Conceptions of teachers on school inclusion and inclusive environment interactions: a review of the literature
A educação inclusiva tem sido um desafio para diferentes profissionais que trabalham na promoção do desenvolvimento de alunos com deficiência. Estes têm a escola como um espaço fundamental para promover o desenvolvimento social, emocional e acadêmico, a partir de oportunidades de vivências estimuladoras da interação e mediação para a aprendizagem de significados e sentidos e que contribuem para processos de resiliência. Este estudo analisou o conteúdo de publicações nacionais da última década (2000-2010) sobre concepções de professores a respeito da inclusão de alunos com alguma necessidade educativa especial (NEE) e interações no contexto educacional inclusivo, também identificando fatores facilitadores e impeditivos da efetivação das diretrizes educacionais existentes. Após busca sistemática na Biblioteca Virtual em Saúde - Psicologia (BVS-PSI), com as palavras-chave: professor, educação inclusiva, interação, educação especial, escola, aprendizagem, concepções, deficiência intelectual, mediação, desenvolvimento e relacionamento, 29 artigos foram recuperados e lidos na íntegra. Verificou-se um predomínio de autores da área da Psicologia e de coletas de dados realizadas via entrevista e questionário. Os estudos apresentaram concepções sobre deficiência ligadas a características individuais que causam limitações. A falta de apoio de equipe especializada, de materiais didáticos e assistivos, de formação e preparo foram apontados como principais fatores que dificultam a efetivação dos princípios inclusivos. A literatura mostra a necessidade de capacitação dos professores. Diante disso, sugerem-se novos estudos sobre a saúde do professor e suas concepções sobre a inclusão escolar, além da necessidade de intervenções escolares baseadas na problematização dos determinantes sociais e históricos associados às deficiências apresentadas e ao mal-estar docente.<br>Inclusive education has been a challenge for different professionals engaged in promoting the development of students with disabilities. Schools have been an essential place for promoting social, emotional and academic development, because they enable opportunities for experiences that stimulate interaction and mediation of learning of significant content, while contributing towards resilience processes. This study analyzed the content of national studies published between 2000 and 2010 on teachers' conceptions of inclusion of pupils with educational needs and interactions in the context of inclusive education; it also aimed to identify factors that facilitate and hinder effectiveness of educational guidelines. After a systematic search of the BVS-PSI portal using the keywords teacher, inclusive education, interaction, special education, school, learning, conceptions, mental disability, mediation, development and relationship, 29 articles were encountered. There was a predominance of authors in the field of psychology. Data collection was conducted via interview and questionnaire. The studies showed deficiencies linked to concepts of individual characteristics that may cause limitations. The lack of support from specialized staff, teaching materials and assistive training and preparation were identified as the main factors hindering successful implementation of inclusive principles. The literature shows the need for teacher development. Given the results, the authors suggest further studies on the health of teachers, investigation into their conceptions of inclusion, as well as the need for intervention in schools considering historical and social determinants of disabilities and factors undermining teacher well-being