Flow characteristics and exchange in complex biological systems as observed by pulsed-field-gradient magnetic-resonance imaging

Water flow through model porous media was studied in the presence of surface relaxation, internal magnetic field inhomogeneities and exchange with stagnant water pools with different relaxation behavior, demonstrating how the apparent flow parameters average velocity, volume flow and flow conducting area in these situations depend on the observation time. To investigate the water exchange process a two component biological model system consisting of water flowing through a biofilm reactor (column packed with methanogenic granular sludge beads) was used, before and after a heat treatment to introduce exchange. We show that correction of the stagnant fluid signal amplitude for relaxation at increasing observation time using the observed relaxation times reveals exchange between the two fractions in the system. Further it is demonstrated how this exchange can be quantifie

Dynamic characteristics of observed sudden warmings

The planetary wave dynamics of stratospheric sudden warmings in the Northern Hemisphere for a large number of observed events that occurred during winters from 1970 to 1975 and 1978 to 1981 are investigated. The analysis describes wave propagation and zonal flow interaction from the troposphere upwards to near 50 km, and in some years to near 80 km. Three primary topics are covered here: (1) the interaction of zonally propagating and quasi-stationary planetary waves during warming events; (2) planetary wave influence on zonal flow near the stratopause; and (3) planetary wave propagation to near 80 km as seen from Stratospheric and Mesospheric Sounder (SAMS) data

Accessible Science: The Natural History of the Connecticut River Valley

Many students take an Earth science or geology course to fulfill a requirement, knowing little to nothing about the field. Like all sciences, geology can appear to have ready answers unconnected to other areas of human endeavor, such as art, religion or philosophy. An interdisciplinary approach to teaching can ameliorate this perception for students who are intimidated by the subject and deepen understanding for those who are already excited about geology. We will examine two strategies designed to support the nature of science while scaffolding student learning in geology: research based digital resources use and museum of natural history visits. One strategy is the effective use of research-based transdisciplinary digital resources. We will use recently developed website resources with a local focus to show how science integrated with history and art can deepen classroom and field trip experiences. The resources integrate historical and cultural resources with modern understandings of geology, drawing upon local libraries, historical societies, archives, municipal and state record offices, and the insights of working geologists and educators. The second strategy is the successful use of Natural History museum assets. The Beneski Museum of Natural History will serve as a backdrop for participants taking a team deep-dive into the local geology of Western Massachusetts using museum linked peer reviewed field guides

Preparing our youth to become citizens its a collective responsibility

Titre de l'écran-titre (visionné le 22 avril 2009).Bibliogr.Webographie

An Analysis of Social Aspects of Forest Stewardship Council Forest Certification in Three Ontario Case Studies

Forest certification is a market-based tool whereby forest management is evaluated against a set of standards that consider environmental, economic and social elements of sustainability. Certificiation is therefore a means of providing customers with the assurance that forest products are originating from sustainability managed forests. It grew out of the ideal of sustainable forest management (SFM) and pulls from its predecessor the concept of multiple dimensions of sustainability. The focus of this project was the international forest certification scheme Forest Stewardship Council (FSC). A comparative case study approach was used to examine the social implications of certification in three FSC cases across Ontario. These cases include: Westwind Forest Stewardship Inc., Nipissing Forest Resource Management Inc., and Clergue Forest Management Inc. The purpose of this study is to examine how, and to what extent, social issues are being addressed. Three case studies are used to examine and compare how different forests deal with the social principles in the certification process. FSC addresses four main social issues which are the focus of research: consultation and public participation processes, recognition of Indigenous rights and culture, employee rights and community rights and well-being. Semi-structured interviews, a questionnaire and a document review were used to examine attitudes and opinions of social issues in certification, as well as the details and potential impacts surrounding specific social issues. This study concludes that FSC certification had only a limited impact on the four social issues in the three case studies. FSC did not make any fundamental changes; although it did improve representation, discussion of social issues, and relationships with stakeholder groups. The Nipissing and Westwind case study participants reported or attributed more changes to FSC certification than did those in the Algoma case study. The results of this study indicate that factors such as the strength of the Ontario forestry regulatory system and the economic downturn of forestry in Canada limited the amount of impact certification had on social issues in the three case studies. The awareness and strength of social principles in FSC policy need to be strengthened in order for certification to make a true impact on forest management in Ontario

Création d’un matériel pédagogique favorisant le développement de la littératie en cinquième secondaire

Cet article a pour but de présenter de façon succincte l’élaboration d’un matériel pédagogique qui a été créé pour favoriser le développement de la littératie chez les élèves de cinquième secondaire (16-17 ans). Six activités respectant les étapes d’une situation d’apprentissage et d’évaluation (SAÉ) ont été conçues pour développer les trois compétences en français, langue d’enseignement, soit « Lire et apprécier des textes variés », « Écrire des textes variés » et « Communiquer oralement selon des modalités variées ». Trois genres littéraires ont été sélectionnés pour la création du matériel : l’album, le roman et la nouvelle. D’une part, nous avons voulu innover avec l’album pour les adolescents, car il s’agit d’un genre méconnu et associé aux plus jeunes. D’autre part, le roman est un genre apprécié par les adolescents tandis que la nouvelle est un genre bref, qui peut surprendre et intéresser les lecteurs adolescents. De surcroit, le roman et la nouvelle sont deux genres prescrits par le programme de formation de l’école québécoise (PFÉQ). Enfin, le matériel pédagogique a été évalué par deux expertes du milieu scolaire qui ont dressé le portrait des points forts et des points à améliorer

The 4-day temperature wave in the winter polar stratosphere

The 4-day wave is a sinusoidal feature in the temperature field of the polar winter stratosphere. Preliminary observations by Venne and Stanford (1979) indicate that it has a zonal wavenumber 1 structure and is eastward propagating with (TURN)4 days period. In this work, additional observational evidence is presented which suggests that the wave represents a normal mode oscillation of the atmosphere. A polar-plane approximation to the earth\u27s sphericity at high latitudes is described and applied to the equations of air parcel motion, yielding solutions that resemble the 4-day wave. In order to obtain these solutions the zonal mean wind is taken to be in solid rotation with no vertical shear, conditions which are typical in the region of largest 4-day wave amplitudes. The substantial changes in the mean zonal wind caused by stratospheric sudden warmings are shown to modify the 4-day wave;The results of spectral analyses performed on infrared radiance data from the Nimbus satellites are also presented. These spectra, for wavenumbers up to 4, reveal a new wave mode with wavenumber 2 structure and westward motion of period (TURN)2.3 days. This wave, found in the Southern Hemisphere winter stratosphere, is tentatively identified as a normal mode wave;The distortions present in satellite data of the Nimbus type, caused by the Doppler shifting of wave phase speed by the satellite motion, are discussed. Simple corrections which provide better estimates of wave amplitude are derived. These corrections are applicable when leakage of power from other wavenumbers is not appreciable