Combining Research and Education: Bioclimatic Zonation along a Canadian Arctic Transect

Scientists and students from five countries combined research and education in an investigation of bioclimatic zonation along a Canadian Arctic transect, from Amund Ringnes Island and Ellesmere Island in the north to the Daring Lake research camp at the southern edge of the tundra in Nunavut. We addressed three important needs in Arctic science: 1) to integrate education and research, 2) to provide field experiences for undergraduates, and 3) to foster international collaboration. We describe five subzones within the Arctic tundra zone. Subzones are defined by the vegetation typical of mesic environments at low elevations and the dominant growth forms of vegetation in these environments. Subzonal boundaries coincide with the northern limits of several species of woody plants with distinct upright or prostrate growth forms, and ultimately with the northern limit of woody plant species. The five subzones, A-E, from north to south, are characterized by dominant growth form: (A) cushion forb, (B) prostrate dwarf shrub, (C) hemiprostrate dwarf shrub, (D) erect dwarf shrub, and (E) low shrub.Des chercheurs et des étudiants de cinq pays ont combiné recherche et éducation dans une étude portant sur la zonation bioclimatique le long d'un transect de l'Arctique canadien, allant de l'île Amund Ringnes et de l'île d'Ellesmere au nord, au camp de recherche du lac Daring situé en bordure sud de la toundra au Nunavut (Canada). On a tenu compte de trois besoins majeurs dans la science de l'Arctique, soit ceux: 1) d'intégrer l'éducation et la recherche; 2) d'offrir aux étudiants de premier cycle des expériences sur le terrain, et 3) de promouvoir la collaboration internationale. On décrit cinq sous-zones à l'intérieur de la zone de toundra de l'Arctique. Les sous-zones sont définies par la végétation typique des milieux à régime d'humidité constant à basse altitude ainsi que par la forme de croissance dominante dans ces habitats. Les limites des sous-zones correspondent aux limites septentrionales de plusieurs espèces de plantes ligneuses ayant des formes de croissance particulières verticales ou procombantes, et en fin de compte à la limite septentrionale des espèces de plantes ligneuses. Les cinq sous-zones (A-E), établies du nord au sud, sont caractérisées par une forme de croissance dominante: A) herbe non graminéenne en coussinet; B) arbuste nain déprimé; C) arbuste nain semi-déprimé; D) arbuste nain dressé, et E) arbuste

Ecosystem restoration and management: Scientific principles and concepts

This paper summarizes current thinking regarding ecological restoration from an ecosystem management point of view. The intended audience is natural resource professionals, natural resource interest groups, and interested members of the public. We discuss ecological restoration concepts in the context of three ecological restoration efforts with which we have been involved and which are particularly important to contemporary public land management: ponderosa pine ecosystems, forest ecosystems of the Western Hemlock Zone of the Pacific Northwest, and tidal wetlands of the Northeast. In discussing these examples we emphasize scientific principles and concepts fundamental to ecological restoration. We close our paper with a discussion of ecological restoration and human habitat needs

Required duration of mass ivermectin treatment for onchocerciasis elimination in Africa: a comparative modelling analysis

Background: The World Health Organization (WHO) has set ambitious targets for the elimination of onchocerciasis by 2020-2025 through mass ivermectin treatment. Two different mathematical models have assessed the feasibility of reaching this goal for different settings and treatment scenarios, namely the individual-based microsimulation model ONCHOSIM and the population-based deterministic model EPIONCHO. In this study, we harmonize some crucial assumptions and compare model predictions on common outputs. Methods: Using a range of initial endemicity levels and treatment scenarios, we compared the models with respect to the following outcomes: 1) model-predicted trends in microfilarial (mf) prevalence and mean mf intensity during 25 years of (annual or biannual) mass ivermectin treatment; 2) treatment duration needed to bring mf prevalence below a provisional operational threshold for treatment interruption (pOTTIS, i.e. 1.4 %), and 3) treatment duration needed to drive the parasite population to local elimination, even in the absence of further interventions. Local elimination was judged by stochastic fade-out in ONCHOSIM and by reaching transmission breakpoints in EPIONCHO. Results: ONCHOSIM and EPIONCHO both predicted that in mesoendemic areas the pOTTIS can be reached with annual treatment, but that this strategy may be insufficient in very highly hyperendemic areas or would require prolonged continuation of treatment. For the lower endemicity levels explored, ONCHOSIM predicted that the time needed to reach the pOTTIS is longer than that needed to drive the parasite population to elimination, whereas for the higher endemicity levels the opposite was true. In EPIONCHO, the pOTTIS was reached consistently sooner than the breakpoint. Co

ENSO and implications on rainfall characteristics with reference to maize production in the Free State Province of South Africa

El Niño-Southern Oscillation (ENSO) plays an important role in the interannual variability of rainfall in most parts of southern Africa. The effects of ENSO on the rainy season characteristics and possible impacts on rainfed maize production were investigated. The rainy season characteristics of concern are the onset of rains, cessation of rains, duration of rainy season and seasonal rainfall total. 309 climate stations over the Free State Province with rainfall data from 1950 to 2008 were analysed. The rainy season indices were further subdivided into El Niño and La Niña years. The differences in averages of the rainy season indices were determined for the negative phase of ENSO versus the overall averages and for the positive phase of ENSO versus the overall averages. The results of the onset of rains show no clear pattern in the Free State with some areas experiencing late onset and others early onset in both El Niño and La Niña years. However, the cessation of rains occurs early during the El Niño and late in La Niña years over most parts of the province. Consequently, the duration of the rainy season is shorter than normal in El Niño years and longer than normal in La Niña years. Seasonal rainfall is also lower than normal in El Niño years while in La Niña years more cumulative rainfall in mostly observed. As a result, maize production is favoured in La Niña years and reduction in production is normally observed during El Niño years.Agricultural Research Council-Institute for Soil, Climate and Water (Project no.GW57/007)http://www.elsevier.com/locate/pcenf201

Localized surface states in HTSC: Alternative mechanism of zero-bias conductance peaks

It is shown that the quasiparticle states localized in the vicinity of surface imperfections of atomic size can be responsible for the zero-bias tunneling conductance peaks in high-Tc superconductors. The contribution from these states can be easily separated from other mechanisms using their qualitatively different response on an external magnetic field.Comment: REVTeX, 4 pages, 2 figs; to be published in PR

International variation in the definition of ‘main condition' in ICD-coded health data

Hospital-based medical records are abstracted to create International Classification of Disease (ICD) coded discharge health data in many countries. The ‘main condition' is not defined in a consistent manner internationally. Some countries employ a ‘reason for admission' rule as the basis for the main condition, while other countries employ a ‘resource use' rule. A few countries have recently transitioned from one of these approaches to the other. The definition of ‘main condition' in such ICD data matters when it is used to define a disease cohort to assign diagnosis-related groups and to perform risk adjustment. We propose a method of harmonizing the international definition to enable researchers and international organizations using ICD-coded health data to aggregate or compare hospital care and outcomes across countries in a consistent manner. Inter-observer reliability of alternative harmonization approaches should be evaluated before finalizing the definition and adopting it worldwid

Citizen Desires, Policy Outcomes, and Community Control

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68810/2/10.1177_107808747200800107.pd

The PKC, HOG and Ca2+ signalling pathways co-ordinately regulate chitin synthesis in Candida albicans

Open Access via PMC2649417Peer reviewedPublisher PD

Circumpolar Arctic vegetation: a hierarchic review and roadmap toward an internationally consistent approach to survey, archive and classify tundra plot data

Satellite-derived remote-sensing products are providing a modern circumpolar perspective of Arctic vegetation and its changes, but this new view is dependent on a long heritage of ground-based observations in the Arctic. Several products of the Conservation of Arctic Flora and Fauna are key to our current understanding. We review aspects of the PanArctic Flora, the Circumpolar Arctic Vegetation Map, the Arctic Biodiversity Assessment, and the Arctic Vegetation Archive (AVA) as they relate to efforts to describe and map the vegetation, plant biomass, and biodiversity of the Arctic at circumpolar, regional, landscape and plot scales. Cornerstones for all these tools are ground-based plant-species and plant-community surveys. The AVA is in progress and will store plot-based vegetation observations in a public-accessible database for vegetation classification, modeling, diversity studies, and other applications. We present the current status of the Alaska Arctic Vegetation Archive (AVA-AK), as a regional example for the panarctic archive, and with a roadmap for a coordinated international approach to survey, archive and classify Arctic vegetation. We note the need for more consistent standards of plot-based observations, and make several recommendations to improve the linkage between plot-based observations biodiversity studies and satellite-based observations of Arctic vegetation

Effect of magnetic field on impurity bound states in high-temperature superconductors

We consider the influence of a magnetic field H on the quasiparticle bound states near scalar impurities in d-wave superconductors. A ``Doppler shift'' in the excitation energies induced by the supercurrent leads to several important effects. At large but finite impurity strength, there are corrections to the energy and width of the impurity-induced resonance, proportional to H^2. On the other hand, in the limit of very strong impurity potential (unitary limit), the bound state is destroyed and acquires a finite width proportional to H/ln H. There are also considerable changes in the asymptotic behaviour of the bound state wave functions.Comment: RevTeX, 5 pages, 2 figure