77 research outputs found

    Cannabis cultivation and deforestation in the Site of Bio Ecological Interest (SIBE) of Bouhachem, Morocco

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    Located in the North of Morocco, Bouhachem forest (about 8000 ha) is threatened by increased deforestation. In order to assure the sustainable management of this forest, the study of its landscape dynamic has been conducted, with emphasis on the role of cannabis cultivation and  deforestation. For this, forest inventory was done, satellite images covering 26 years period were analysed, interviews of stakeholders conducted and the archives on the management of the forest checked. The forest basal area is 34.6 m²/ha in average. Canopy closure, stand density, rock exposition, and stump density average values were respectively 43%, 1001 stem/ha, 24% 187 stump/ha, for a wild stump rate of 18.7%. The total forest cover has shrunk by 11% between 1984 and 2010.The main reasons of forest depletion are: demographic explosion, erosion land slide, illegal logging and cannabis cultivation around which are gravitating an increased demand of forest resources, livestock grazing, corruption, poor surveillance, forest fire.Keywords: Bouhachem forest, livestock grazing, corruption, remote sensing and GIS, model of deforestatio

    Two-dimensional solitons with hidden and explicit vorticity in bimodal cubic-quintic media

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    We demonstrate that two-dimensional two-component bright solitons of an annular shape, carrying vorticities (m,±m)(m,\pm m) in the components, may be stable in media with the cubic-quintic nonlinearity, including the \textit{hidden-vorticity} (HV) solitons of the type (m,−m)(m,-m), whose net vorticity is zero. Stability regions for the vortices of both (m,±m)(m,\pm m) types are identified for m=1m=1, 2, and 3, by dint of the calculation of stability eigenvalues, and in direct simulations. A novel feature found in the study of the HV solitons is that their stability intervals never reach the (cutoff) point at which the bright vortex carries over into a dark one, hence dark HV solitons can never be stable, contrarily to the bright ones. In addition to the well-known symmetry-breaking (\textit{external}) instability, which splits the ring soliton into a set of fragments flying away in tangential directions, we report two new scenarios of the development of weak instabilities specific to the HV solitons. One features \textit{charge flipping}, with the two components exchanging the angular momentum and periodically reversing the sign of their spins. The composite soliton does not split in this case, therefore we identify such instability as an \textit{intrinsic} one. Eventually, the soliton splits, as weak radiation loss drives it across the border of the ordinary strong (external) instability. Another scenario proceeds through separation of the vortex cores in the two components, each individual core moving toward the outer edge of the annular soliton. After expulsion of the cores, there remains a zero-vorticity breather with persistent internal vibrations.Comment: 10 pages, 11 figure

    Optical, magneto-optical properties and fiber-drawing ability of tellurite glasses in the TeO2-ZnO-BaO ternary system

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    The presented work is focused on the optical and magneto-optical characterization of TeO2-ZnO-BaO (TZB) tellurite glasses. We investigated the refractive index and extinction coefficient dispersion by spectroscopic ellipsometry from ultraviolet, 0.193 um, up to mid infrared, 25 um spectral region. Studied glasses exhibited large values of linear (n632 = 1.91-2.09) and non-linear refractive index (n2 = 1.20-2.67x10-11 esu), Verdet constant (V632 = 22-33 radT-1m-1) and optical band gap energy (Eg = 3.7-4.1 eV). The materials characterization revealed that BaO substitution by ZnO leads (at constant content of TeO2) to an increase in linear and nonlinear refractive index as well as Verdet constant while the optical band gap energy decreases. Fiber drawing ability of TeO2-ZnO-BaO glassy system has been demonstrated on 60TeO2-20ZnO-20BaO glass with presented mid infrared attenuation coefficient. Specific parameters such as dispersion and single oscillator energy, Abbe number, and first-/ third-order optical susceptibility are enclosed together with the values of magneto-optic anomaly derived from the calculation of measured dispersion of the refractive index

    The effect of time-to-surgery on outcome in elderly patients with proximal femoral fractures

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    <p>Abstract</p> <p>Background</p> <p>Whether reducing time-to-surgery for elderly patients suffering from hip fracture results in better outcomes remains subject to controversial debates.</p> <p>Methods</p> <p>As part of a prospective observational study conducted between January 2002 and September 2003 on hip-fracture patients from 268 acute-care hospitals all over Germany, we investigated the relationship of time-to-surgery with frequency of post-operative complications and one-year mortality in elderly patients (age ≥65) with isolated proximal femoral fracture (femoral neck fracture or pertrochanteric femoral fracture). Patients with short (≤12 h), medium (> 12 h to ≤36 h) and long (> 36 h) times-to-surgery, counting from the time of the fracture event, were compared for patient characteristics, operative procedures, post-operative complications and one-year mortality.</p> <p>Results</p> <p>Hospital data were available for 2916 hip-fracture patients (mean age (SD) in years: 82.1 (7.4), median age: 82; 79.7% women). Comparison of groups with short (n = 802), medium (n = 1191) and long (n = 923) time-to-surgery revealed statistically significant differences in a few patient characteristics (age, American Society of Anesthesiologists ratings classification and type of admission) and in operative procedures (total hip endoprosthesis, hemi-endoprosthetic implants, other osteosynthetic procedures). However, comparison of these same groups for frequency of postoperative complications revealed only some non-significant associations with certain complications such as post-operative bleeding requiring treatment (early surgery patients) and urinary tract infections (delayed surgery patients). Both unadjusted rates of one-year all-cause mortality (between 18.1% and 20.5%), and the multivariate-adjusted hazard ratios (HR for time-to-surgery: 1.04; p = 0.55) showed no association between mortality and time-to-surgery.</p> <p>Conclusion</p> <p>Although this study found a trend toward more frequent post-operative complications in the longest time-to-surgery group, there was no effect of time-to-surgery on mortality. Shorter time-to-surgery may be associated with somewhat lower rates of post-operative complications such as decubitus ulcers, urinary tract infections, thromboses, pneumonia and cardiovascular events, and with somewhat higher rates of others such as post-operative bleeding or implant complications.</p

    Optical and structural properties of new chalcohalide glasses

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    New class of chalcohalide glasses has been prepared in the GeS2–In2S3–CsI system with regard to their potential non-linear properties. The study of glass-forming region was undertaken to select glassy compositions, which present high non-linear (NL) optical properties with a low two-photon absorption. Thermal analyses, structural examination by Raman spectroscopy, non-linear optical measurements were investigated as a function of CsI contents. Introduction of CsI has shifted the band-gap edge towards the blue region of the absorption optical spectrum and therefore has limited the two-photon absorption. Their NL refractive index n2 are 60 times higher than silica glasses without any NL absorption. Moreover, second harmonic signal was observed in thermally poled samples similar to silica glass. However, this second order non-linearity is not temporally stable

    Capture the fracture: a best practice framework and global campaign to break the fragility fracture cycle

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    Summary The International Osteoporosis Foundation (IOF) Capture the Fracture Campaign aims to support implementation of Fracture Liaison Services (FLS) throughout the world. Introduction FLS have been shown to close the ubiquitous secondary fracture prevention care gap, ensuring that fragility fracture sufferers receive appropriate assessment and intervention to reduce future fracture risk. Methods Capture the Fracture has developed internationally endorsed standards for best practice, will facilitate change at the national level to drive adoption of FLS and increase awareness of the challenges and opportunities presented by secondary fracture prevention to key stakeholders. The Best Practice Framework (BPF) sets an international benchmark for FLS, which defines essential and aspirational elements of service delivery. Results The BPF has been reviewed by leading experts from many countries and subject to beta-testing to ensure that it is internationally relevant and fit-for-purpose. The BPF will also serve as a measurement tool for IOF to award ‘Capture the Fracture Best Practice Recognition’ to celebrate successful FLS worldwide and drive service development in areas of unmet need. The Capture the Fracture website will provide a suite of resources related to FLS and secondary fracture prevention, which will be updated as new materials become available. A mentoring programme will enable those in the early stages of development of FLS to learn from colleagues elsewhere that have achieved Best Practice Recognition. A grant programme is in development to aid clinical systems which require financial assistance to establish FLS in their localities. Conclusion Nearly half a billion people will reach retirement age during the next 20 years. IOF has developed Capture the Fracture because this is the single most important thing that can be done to directly improve patient care, of both women and men, and reduce the spiralling fracture-related care costs worldwide.</p

    Patients with femoral or distal forearm fracture in Germany: a prospective observational study on health care situation and outcome

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    BACKGROUND: Distal radius and proximal femoral fractures are typical injuries in later life, predominantly due to simple falls, but modulated by other relevant factors such as osteoporosis. Fracture incidence rates rise with age. Because of the growing proportion of elderly people in Western industrialized societies, the number of these fractures can be expected to increase further in the coming years, and with it the burden on healthcare resources. Our study therefore assessed the effects of these injuries on the health status of older people over time. The purpose of this paper is to describe the study method, clinical parameters of fracture patients during hospitalization, mortality up to one and a half years after discharge in relation to various factors such as type of fracture, and to describe changes in mobility and living situation. METHODS: Data were collected from all consecutive patients (no age limit) admitted to 423 hospitals throughout Germany with distal radius or femoral fractures (57% acute-care, femoral and forearm fractures; 43% rehabilitation, femoral fractures only) between January 2002 and September 2003. Polytrauma and coma patients were excluded. Demographic characteristics, exact fracture location, mobility and living situation, clinical and laboratory parameters were examined. Current health status was assessed in telephone interviews conducted on average 6–7 months after discharge. Where telephone contact could not be established, at least survival status (living/deceased/date of death) was determined. RESULTS: The study population consisted of 12,520 femoral fracture patients (86.8% hip fractures), average age 77.5 years, 76.5% female, and 2,031 forearm fracture patients, average age 67.6 years, 81.6% female. Women's average age was 6.6 (femoral fracture) to 10 years (forearm fracture) older than men's (p < 0.0001). Only 4.6% of femoral fracture patients experienced changes in their living situation post-discharge (53% because of the fracture event), although less than half of subjects who were able to walk without assistive devices prior to the fracture event (76.7%) could still do so at time of interview (34.9%). At time of interview, 1.5% of subjects were bed-ridden (0.2% before fracture). Forearm fracture patients reported no change in living situation at all. Of the femoral fracture patients 119 (0.95%), and of the forearm fracture patients 3 (0.15%) died during hospital stay. Post-discharge (follow-up one and a half years) 1,463 femoral fracture patients died (19.2% acute-care patients, 8.5% rehabilitation patients), but only 60 forearm fracture patients (3.0%). Ninety percent of femoral fracture deaths happened within the first year, approximately 66% within the first 6 months. More acute-care patients with a pertrochanteric fracture died within one year post-discharge (20.6%) than patients with a cervical fracture (16.1%). CONCLUSION: Mortality after proximal femoral fracture is still alarmingly high and highest after pertrochanteric fracture. Although at time of interview more than half of femoral fracture patients reported reduced mobility, most patients (96%) attempt to live at home. Since forearm fracture patients were on average 10 years younger than femoral fracture patients, forearm fractures may be a means of diagnosing an increased risk of later hip fractures

    Construire un modèle graphique spatial pour développer un modèle de simulation : quel apport pour la gestion des ressources en ligneux ?

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    The interest of modelling spatial configurations is expected for the formalisation of territorial diagnosis and for the possibility of simulating prospective scenarios of territorial evolution. Graphic modelling, through the use of "chorèmes", provides interesting possibilities to establish the diagnosis of spatial configurations. This formalism has until now been little used in respect of the natural resources deliberate management process. Furthermore, system modelling with the formalism of system dynamics allows us to clarify the state variables and the qualitative structure of the territorial system explored. It also provides value to the relations in order to simulate. Within the context of wood resource management in the Kaélé and Gadas village region (North-Cameroon), the question of the contribution of spatial configurations modelling is raised : this paper assesses the possibility of a link between graphic and system modelling. The retained "chorèmes" are translated in terms of the system dynamics. Graphic modelling is then replaced into a perspective of deliberate management assistance.L`intérêt de la modélisation des configurations spatiales est attendu dans la formalisation de diagnostics territoriaux et dans la possibilité de réaliser des simulations dans l`élaboration de scénarios prospectifs de l`évolution des territoires. La modélisation graphique, par l`usage des chorèmes, offre la possibilité d`établir des diagnostics des configurations spatiales. Ce formalisme a, jusqu`à présent, été peu inséré dans les processus de gestion intentionnelle. Par ailleurs, la modélisation systémique avec le formalisme de la dynamique des systèmes, permet non seulement d`expliciter les variables d`état et la structure qualitative du système territorial envisagé, mais également d`évaluer les relations afin de réaliser des simulations. Dans le cadre de la gestion des ressources en ligneux dans la région de Kaélé et du village de Gadas (Nord-Cameroun), la question de l`apport de la modélisation des configurations spatiales est posée. La présente contribution évalue les possibilités de construire un modèle de simulation à partir d`un modèle graphique, à partir du cas de Gadas. Les chorèmes retenus sont traduits en termes de dynamique de système. La modélisation graphique est alors replacée dans une perspective d`aide à la gestion intentionnelle

    Outils et méthodes : synthèse de l'atelier 4

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    Extrait de documentUn thème fédérateur : les bases de connaissances pour la gestion des ressources et des territoires. Les éléments de synthèse issus des débats. La présentation des communications et les débats qui ont suivi ont permis de mettre en exergue plusieurs points qui posent questions : la question du champ spatial d`une étude et du découpage d`un espace géographique ; la question de la pertinence des modèles de représentations de l'espace véhiculés par les pays du Nord pour la recherche-action dans les pays du Sud ; la question des représentations de l`espace et des raisonnements spatiaux des acteurs impliqués dans la gestion des ressources et des territoires ; la question de la dynamique d`un espace abordée selon différentes manières ; la question des bases de connaissances ; la question des outils et méthodes de la recherche-action pour l`appui au développement territorial
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