bluuebunny/crossref_metadata_2025 huggingface dataset:
A Stereovision System for Real Time Obstacle Avoidance by Unmanned Aerial Vehicle
Authors: Cieśluk Jakub , Gosiewski Zdzisław
Published: March 2013

The necessary hardware and stereovision obstacle avoidance algorithm used by UAV (unmanned aerial vehicles) are described in this paper. The algorithm bases on method of matching the areas of image by using the standard SAD (sum of absolute differences) as a measure of fit. The rapid machining of the image is done by compare the windows areas. Method didn't check individual pixels what is important feature. The application target is operating in unknown environment with the changing light conditions which may disturb the proper operation of the obstacle avoidance algorithm. To reduce the reflection effect the averaging filter for each frame image is applied. This is realized by compare of the average brightness values in successive video frames. It allows to control the factor of the achromatic color in the image. To increase the performance, in the anti-collision system the algorithm controls only the area being the center of the picture connected with the direction of the UAV flight. When the obstacle is detected the image is tested globally to find the direction of the avoidance maneuver. Onboard computer for anti-collision system uses a serial communication with the autopilot ArdupilotMega. A quadrocopter (multicopter that is propelled by four rotors) was chosen as a control object.
Application of Unfalsified Control Theory in Controlling MAV
Authors: Wolniakowski Adam , Mystkowski Arkadiusz
Published: March 2013

Controlling the flight of Micro Aerial Vehicles (MAV) is a highly challenging task, mostly due to nonlinearity of their models and highly varying longitudinal and lateral derivatives coefficients [. As such, it requires a proper form of robust control. The demand for such control is very high, as it is required in many applications. The following paper presents the application of Unfalsified Control Theory developed by Michael G. Safonov [1, 2, 6, . This interesting approach is based on the adaptive switching control, and does not require any previous knowledge of the controlled plant. The controlled dynamics is decoupled due to longitudinal and lateral motion of the Bell 540 single-delta wing micro aerial vehicle. The work involves design and simulation of the proper robust controller. The simulation is based on already obtained nominal model of the Bell 540 vehicle [. The developed controllers were proved to be efficient, based on performed calculations and simulation in Matlab.
Modelling of Dynamic and Control of Six-Rotor Autonomous Unmanned Aerial Vehicle
Authors: Ołdziej Daniel , Gosiewski Zdzisław
Published: March 2013

The paper describes matters of modeling and control of aerial vehicle in rotorcraft configuration. Equations of motion were derived and dynamic model of six-rotor was build. To find the best adjustment of model to real object the dynamics of the drives was joined to the control plant model. Trimming and linearization were performed. Open loop system and LQR controller were checked in simulation environment. Next the faults of the actuator/sensor elements were arranged and the minimal number of observed outputs and drives for LQR stabilization process were specified.
Optimization of Lift Force of Mini Quadrotor Helicopter by Changing of Gap Size between Rotors
Authors: Aleksandrov Dmitri , Penkov Igor
Published: March 2013

This paper describes comparison between virtual simulation of quadrotor flying platforms (mini UAV - Unmanned Aerial Vehicle) and real experiments. In quadrotor helicopter (quadrocopter) air flows that are going out from rotors and affecting each other were simulated. Analysis of several helicopters that have different distances between rotors on different angular velocities were compared. During virtual simulation (with CFD Computational Fluid Dynamics software) there were conducted similar to real experiments with the use of scanned rotors (with 3D scanner) and same environment conditions. These experiments were compared with real experiments. Optimal gap distance between rotors is determined, when helicopter mass is minimum and rotors are creating maximum lifting force and consuming minimum energy (minimum impact on air flows to each other).
Simulation Method of UAV Avionics System Designing
Authors: Wojtowicz Konrad , Sobieraj Wiesław , Brzozowski Bartosz
Published: March 2013

Avionics system software development is a sophisticated process depended on not fully specified factors. Therefore, essential steps in the development process are tests and verification. In this aim the virtual environment was constructed and prepared for the tests with the target software and the hardware to eliminate hardware defects and software bugs before first flight. The concept of virtual environment was established and developed after unsuccessful flights with long term prepared aircraft models. There was assumed that modelling methods applied separately to frame, engine and control system were not sufficient. There was requirement for complex simulation platform prepared to test whole aircraft in various environment conditions. In the first step the designing process was identified and milestones were placed inside (Fig. 1)
UAV Autonomous Formation Flight Experiment with Virtual Leader Control Structure
Authors: Gosiewski Zdzisław , Ambroziak Leszek
Published: March 2013

The problem of autonomous formation flight control of UAVs (Unmanned Aerial Vehicles) is presented in the paper. A decentralized control method of the autonomous formation flight realization is described. A practical approach to the UAV formation flight control was shown. The applied method bases on the information exchange between flying objects. The shared data concern the position and velocity of the aircraft. Constructed UAV airframe was presented as well as used autopilot, developed formation flight control unit, wireless communication links and used data packet structure. The main aim of this work was the in-flight tests. The test of formation flight with Virtual Leader (VL) was examined. The autopilot reactions to the incoming data packets with desired altitude, airspeed and heading from formation flight controller were checked. During the flights the longitudinal and lateral positions of the UAV, orientation angles (pitch, roll, yaw), angular velocities (pitch rate, roll rate, yaw rate) and many other flight parameters were logged. The research and flight tests checked and verified the developed method of formation flight control.
Unmanned Air Vehicle Research Simulator - Prototyping and Testing of Control and Navigation Systems
Authors: Rzucidło Paweł
Published: March 2013

This paper presents an experimental research simulator of an Unmanned Aerial Vehicle (UAV) and supporting systems, designed at the Department of Avionics and Control, Rzeszow University of Technology. The research simulator enables hardware-in-the-loop testing of an autopilot, actuators, the ground control station and telemetry modules. Particular hardware blocks can be integrated with real-time environment with the use of a CAN data bus, Ethernet interface and a set of popular serial interfaces. Current experiments support development and hardware-in-the-loop testing of advanced flight control and navigation systems of a small UAV (taking into account both the on-board and the ground segments).
Numerical and Experimental Testing of Bearingless Induction Motor
Authors: Gosiewski Zdzisław , Henzel Maciej , Falkowski Krzysztof , Żokowski Mariusz
Published: March 2013

The bearingless systems are a key technology in many power mechatronic applications. The topic of the paper reports the original, very relevant and very timely research. The methods of numerical and experimental testing of the bearingless induction motor, presented in the paper revised, are convergent with the directions of up-to-date research in this domain.
Possibilities of Application of Amorphous Fe77Cr2B16Si5 Alloys in Different States of Thermal Relaxation as Magnetic Tensile Force Sensors
Authors: Salach Jacek , Szewczyk Roman , Bieńkowski Adam , Jackiewicz Dorota
Published: March 2013

Paper discusses the possible of application of iron-based amorphous Fe77Cr2B16Si5 alloys for tensile force sensors. In proposed sensor uniform stresses were generated in direction of the ribbon ring core axis. As a result stresses were perpendicular to the magnetizing field direction, what increases sensor sensitivity as well as simplified analyses. The results show high magnetoelastic sensitivity of Fe77Cr2B16Si5 amorphous alloy. Moreover, this magnetoelastic sensitivity increases during the annealing process, which is connected with thermal relaxation of amorphous alloy.
Control Driven Advances in Smart Rotating Machinery
Authors: Sawicki Jerzy T.
Published: March 2013

In the last twenty years, there has been significant progress in the design of rotating machinery equipped with smart components and embedded functions. This was accompanied by developments in actuators, sensors and power electronics technologies, advances in data acquisition and signal processing, as well as developments in control theory. This paper will provide a brief overview of the current state of art and it will illustrate examples of the applications of smart technologies applied to rotating machines. Several technologies, either most recently developed or under development will be presented, which involve active control and are relevant to smart solutions applied to rotating machinery.
Harmonic Analysis of Self-Excited Acoustical System for Stress Changes Measurement in Compressed Steel Structural Section
Authors: Kwaśniewski Janusz , Dominik Ireneusz , Lalik Krzysztof , Szymański Rafał
Published: March 2013

This paper presents the application of the Self-exited Acoustical System (SAS) for monitoring stress changes in steel. The change of the speed of wave propagation, which is associated with the change of the resonance frequency in the system is caused by the deformation of the examined material. The SAS system is based on this phenomenon and can be used for an indirectly measurement of the stresses changes in the steel. Preliminary calculations such as static analysis and dynamic simulation of the system were carried out. The results of calculations were compared with the experimental data of the steel beam.
Mid-upper tropospheric methane retrieval from IASI and its validation
Authors: Xiong X. , Barnet C. , Maddy E. S. , Gambacorta A. , King T. S. , Wofsy S. C.
Published: March 2013

Abstract. Mid-upper tropospheric atmospheric methane (CH4), as an operational product at NOAA's (National Oceanic and Atmospheric Administration) Comprehensive Large Array-data Stewardship System (CLASS), has been retrieved from the Infrared Atmospheric Sounding Interferometer (IASI) since 2008. This paper provides a description of the retrieval method and the validation using 596 CH4 vertical profiles from aircraft measurements by the HIAPER Pole-to-Pole Observations (HIPPO) program over the Pacific Ocean. The degree of freedom of the CH4 retrieval is mostly less than 1.5, and it decreases under cloudy conditions. The most sensitivity layer is between 100–600 hPa in the tropics, 200–750 hPa in the mid to high latitude. Validation is accomplished using aircraft measurements (convolved by applying the averaging kernels) collocated with all the retrieved profiles within 200 km and in the same day, and the results show that, on average, the largest error of CH4 occurs at 300–500 hPa, and the bias in the trapezoid of 374–477 hPa is −1.74% with residual standard deviation of 1.20%. The retrieval error is relatively larger in the high northern latitude regions and/or under cloudy conditions. The main reasons for this negative bias might be due to the uncertainty in the spectroscopy near methane Q-branch and/or the empirical bias correction, plus cloud-contamination in the cloud-cleared radiances. It is expected for NOAA to generate the CH4 product for 20+ yr using similar algorithm from three similar thermal infrared sensors, i.e. Atmospheric Infrared Sounder (AIRS), IASI and the Cross-track Infrared Sounder (CrIS). Such a unique product will provide a supplementary to current ground-based observation network, particularly in the Arctic, for monitoring the CH4 cycle, its transport and trend associated with climate change.
Decreased carbon limitation of litter respiration in a mortality-affected piñon–juniper woodland
Authors: Berryman E. , Marshall J. D. , Rahn T. , Litvak M. , Butnor J.
Published: March 2013

Abstract. Microbial respiration depends on microclimatic variables and carbon (C) substrate availability, all of which are altered when ecosystems experience major disturbance. Widespread tree mortality, currently affecting piñon–juniper ecosystems in southwestern North America, may affect C substrate availability in several ways, for example, via litterfall pulses and loss of root exudation. To determine piñon mortality effects on C and water limitation of microbial respiration, we applied field amendments (sucrose and water) to two piñon–juniper sites in central New Mexico, USA: one with a recent (< 1 yr), experimentally induced mortality event and a nearby site with live canopy. We monitored the respiration response to water and sucrose applications to the litter surface and to the underlying mineral soil surface, testing the following hypotheses: (1) soil respiration in a piñon–juniper woodland is water- and labile C-limited in both the litter layer and mineral soil; (2) piñon mortality reduces the C limitation of litter respiration; and (3) piñon mortality enhances the C limitation of mineral soil respiration. Litter respiration at both sites responded to increased water availability, yet surprisingly, mineral soil respiration was not limited by water. Consistent with hypothesis 2, C limitation of litter respiration was lower at the recent mortality site compared to the intact canopy site. Applications to the mineral soil showed evidence of reduction in CO2 flux on the girdled site and a non-significant increase on the control. We speculate that the reduction may have been driven by water-induced carbonate dissolution, which serves as a sink for CO2 and would reduce the net flux. Widespread piñon mortality may decrease labile C limitation of litter respiration, at least during the first growing season following mortality.
Forest stand age information improves an inverse North American carbon flux estimate
Authors: Deng F. , Chen J. M. , Pan Y. , Peters W. , Birdsey R. , McCullough K. , Xiao J.
Published: March 2013

Abstract. Atmospheric inversions have become an important tool in quantifying carbon dioxide (CO2) sinks and sources at a variety of spatiotemporal scales, but associated large uncertainties restrain the inversion research community from reaching agreements on many important subjects. We enhanced an atmospheric inversion of the CO2 flux for North America by introducing spatially-explicit information on forest stand age for US and Canada as an additional constraint, since forest carbon dynamics are closely related to time since disturbance. To use stand age information in the inversion, we converted stand age into an age factor, and included the covariances between sub-continental regions in the inversion based on the similarity of the age factors. Our inversion results show that, considering age factors, regions with recently-disturbed or old forests are often nudged towards carbon sources, while regions with middle-aged productive forests are shifted towards sinks. This conforms to stand age effects observed in flux networks. At the sub-continental level, our inverted carbon fluxes agree well with continuous estimates of net ecosystem carbon exchange (NEE) upscaled from eddy covariance flux data (EC) based on MODIS data. Inverted fluxes with the age constraint exhibit stronger correlation to these upscaled NEE estimates than those inverted without the age constraint. While the carbon flux at the continental and sub-continental scales is predominantly determined by atmospheric CO2 observations, the age constraint is shown to have potential to improve the inversion of the carbon flux distribution among sub-continental regions, especially for regions lacking atmospheric CO2 observations.
Spatiotemporal distributions of Fukushima-derived radionuclides in surface sediments in the waters off Miyagi, Fukushima, and Ibaraki Prefectures, Japan
Authors: Kusakabe M. , Oikawa S. , Takata H. , Misonoo J.
Published: March 2013

Abstract. Spatiotemporal distributions of anthropogenic radionuclides in surface sediments off Miyagi, Fukushima, and Ibaraki Prefectures were analyzed on the basis of data collected during the monitoring program launched by the Japanese Ministry of Education, Sports, Science and Technology in 2011 right after the Fukushima Nuclear Power Plant accident. Concentrations of 137Cs in the surface sediments varied spatially by two orders of magnitude from 1.7 to 580 Bq kg-dry−1, and there was no obvious correlation between 137Cs concentration and the proximity of the sampling location to the site of the accident. The total inventory of 137Cs accumulated in the upper 3 cm of surface sediment in the monitoring area was estimated to be 3.78 × 1013 Bq, that is 0.1–2% of the total 137Cs flux from the plant to the ocean as a result of the accident (the percentage depends on the model used to estimate the total flux). The spatial variations of 137Cs concentration and inventory depended on two main factors: the 137Cs concentration in the overlying water during the first several months after the accident and the physical characteristics of the sediment (water content and bulk density). The temporal variations of the concentrations of other anthropogenic radionuclides (90Sr, 95Nb, 110 mAg, 125Sb, 129Te, and 129 mTe) in the sediments were also investigated. The temporal variations of the activity ratios of these nuclides to 137Cs suggest that before the Fukushima-derived nuclides became homogeneous in seawater, they were removed from the water to the sediment.
Quantification of the Greenland ice sheet contribution to Last Interglacial sea level rise
Authors: Stone E. J. , Lunt D. J. , Annan J. D. , Hargreaves J. C.
Published: March 2013

Abstract. During the Last Interglacial period (~ 130–115 thousand years ago) the Arctic climate was warmer than today, and global mean sea level was probably more than 6.6 m higher. However, there are large discrepancies in the estimated contributions to this sea level change from various sources (the Greenland and Antarctic ice sheets and smaller ice caps). Here, we determine probabilistically the likely contribution of Greenland ice sheet melt to Last Interglacial sea level rise, taking into account ice sheet model parametric uncertainty. We perform an ensemble of 500 Glimmer ice sheet model simulations forced with climatologies from the climate model HadCM3, and constrain the results with palaeodata from Greenland ice cores. Our results suggest a 90% probability that Greenland ice melt contributed at least 0.6 m, but less than 10% probability that it exceeded 3.5 m, a value which is lower than several recent estimates. Many of these previous estimates, however, did not include a full general circulation climate model that can capture atmospheric circulation and precipitation changes in response to changes in insolation forcing and orographic height. Our combined modelling and palaeodata approach suggests that the Greenland ice sheet is less sensitive to orbital forcing than previously thought, and it implicates Antarctic melt as providing a substantial contribution to Last Interglacial sea level rise. Future work should assess additional uncertainty due to inclusion of basal sliding and the direct effect of insolation on surface melt. In addition, the effect of uncertainty arising from climate model structural design should be taken into account by performing a multi-climate-model comparison.
Suspended sediment concentration–discharge relationships in the (sub-) humid Ethiopian highlands
Authors: Guzman C. D. , Tilahun S. A. , Zegeye A. D. , Steenhuis T. S.
Published: March 2013

Abstract. Loss of top soil and subsequent filling up of reservoirs in much of the lands with variable relief in developing countries degrades environmental resources necessary for subsistence. In the Ethiopia highlands, sediment mobilization from rain-fed agricultural fields is one of the leading factors causing land degradation. Sediment rating curves, produced from long-term sediment concentration and discharge data, attempt to predict suspended sediment concentration variations, which exhibit a distinct shift with the progression of the rainy season. In this paper, we calculate sediment rating curves and examine this shift in concentration for three watersheds in which rain-fed agriculture is practiced to differing extents. High sediment concentrations with low flows are found at the beginning of the rainy season of the semi-monsoonal climate, while high flows and low sediment concentrations occur at the end of the rainy season. Results show that a reasonably unique set of rating curves were obtained by separating biweekly data into early, mid, and late rainfall periods and by making adjustments for the ratio of plowed cropland. The shift from high to low concentrations suggests that diminishing sediment supply and dilution from greater base flow during the end of the rainfall period play important roles in characterizing changing sediment concentrations during the rainy season.
Brief communication Decreasing fires in a Mediterranean region (1970–2010, NE Spain)
Authors: Turco M. , Llasat M. C. , Tudela A. , Castro X. , Provenzale A.
Published: March 2013

Abstract. We analyse the recent evolution of fires in Catalonia (north-eastern Iberian Peninsula), a typical Mediterranean region. We examine a homogeneous series of forest fires in the period 1970–2010. During this period, more than 9000 fire events greater than 0.5 ha were recorded, and the total burned area was more than 400 kha. Our analysis shows that both the burned area and number of fire series display a decreasing trend. Superposed onto this general decrease, strong oscillations on shorter time scales are evident. After the large fires of 1986 and 1994, the increased effort in fire prevention and suppression could explain part of the decreasing trend. Although it is often stated that fires have increased in Mediterranean regions, the higher efficiency in fire detection could have led to spurious trends and misleading conclusions.
Transport of AABW through the Kane Gap, tropical NE Atlantic
Authors: Morozov E. G. , Tarakanov R. Yu. , van Haren H.
Published: March 2013

Abstract. We study low-frequency flow of Antarctic Bottom Water through the Kane Gap (9° N) in the Atlantic. The measurements in the Kane Gap include five visits with CTD sections in 2009–2012 and a year-long record of currents using three AquaDopp current-meters. We found an alternating regime of flow, which changes direction several times during a year. The velocities reach 0.21 m s−1. The transport of Antarctic Bottom Water (< 1.9 °C) based on the mooring and LADCP data varies by ± 0.3 Sv.
Comparison of Intrastromal Corneal Ring Segment Implantation only and in Combination with Collagen Crosslinking for Keratoconus
Authors: Çakir Hanefi , Pekel Gökhan , Perente Irfan , Genç Selim
Published: March 2013

Purpose

To compare visual outcomes, corneal astigmatism, and keratometric readings in patients with progressive keratoconus undergoing intrastromal corneal ring implantation (ICRSI) only and in combination with ultraviolet A riboflavin mediated corneal collagen crosslinking (CXL).

Methods

In this retrospective comparative study, there were 2 groups of keratoconus patients. Group 1 consisted of only ICRSI patients. Group 2 consisted of combined ICRSI-CXL patients. Preoperative and postoperative uncorrected distance visual acuity (UCDVA) and best-corrected distance visual acuity (BCDVA), spherical error, cylindrical error, and mean keratometry were compared.

Results

The study evaluated 166 eyes of 121 patients with a mean age of 24.74 years. The UCDVA improved from 0.24 to 0.37 in group 1 and from 0.24 to 0.42 in group 2 at the last visit. The BCDVA improved from 0.34 to 0.62 in group 1 and from 0.31 to 0.67 in group 2. Spherical error decreased from −5.05 D to −1.65 D in group 1 and from −4.82 D to −1.52 D in group 2. Cylindrical error decreased from −6.06 D to −3.47 D in group 1 and from −5.66 D to −3.20 D in group 2. Mean keratometry values decreased from 51.89 D to 47.96 D in group 1 and from 50.89 D to 46.91 D in group 2. p Value was ≥0.05 in group comparisons. Ring explantation due to corneal melting was applied in 3 eyes.

Conclusions

Both combined ICRSI-CXL and ICRSI-only groups experienced favorable outcomes, without statistical difference in any studied effect of both treatment strategies.
Formulation of a Dry Weight Bioimpedance Index in Hemodialysis Patients
Authors: Cridlig Joëlle , Alquist Maria , Kessler Michèle , Nadi Mustapha
Published: March 2013

Hydration status has a major impact on hemodialysis (HD) patients. Overhydration is related to hypertension, pulmonary and peripheral edema, and other cardiovascular events; while dehydration is related to hypotension, and other severe ischemic symptoms. All result in increased morbidity and mortality. Bioimpedance has been newly developed to measure the amount of water in the body. Several predictive equations were used, taken from demographic and anthropometric data. The purpose of this study was to evaluate the body composition of HD patients and to propose a hydration index. We performed bioimpedance measures with the Tanita TBF-300 scale, which calculates Total Body Water (TBW). The tool was reliable, with good reproducibility. However, we found significant differences between weight variations (dW) and TBW variations (dTBW) during HD sessions. This paper proposes a hydration index (I=dW-dTBW), with the hypothesis that dry weight is reached when I=0, while i>0 or I<0 indicate overhydrated or dehydrated, respectively. In this study, the changes in the index corresponded to the variations in weight and hydration state. We conclude that impedancemetry is a currently available technique that can be used to estimate TBW in HD patients. Although the index has to be improved by complementary studies, it may be a good guide to assess the dry weight achieved.
 Aulas de educação física e inclusão: um estudo de caso com a deficiência física
Authors: Palma Luciana Erina , Lehnhard Greice Rosso
Published: March 2013

http://dx.doi.org/10.5902/1984686X2284Este estudo teve como objetivo descrever a participação de um aluno com deficiência física em aulas de Educação Física em uma turma do 2º ano do Ensino Fundamental de uma escola regular. Foram observadas sete aulas de Educação Física da turma, as informações foram registradas em uma Ficha de Observação e, posteriormente, foi aplicada uma entrevista com roteiro pré-estabelecido ao aluno com deficiência. Os dados foram analisados a partir de duas categorias: a) Aluno com Deficiência e a Participação nas Aulas de Educação Física e b) O Relacionamento entre aluno com Deficiência e Colegas. A partir dos dados observou-se que a maioria das atividades propostas pela professora nas aulas de Educação Física favoreceu a inclusão do aluno que possuía deficiência física, além disso, houve interação entre ele e os colegas. Sendo assim, podemos afirmar que a inclusão está sendo efetivada na turma e nas aulas de Educação Física pesquisadas.Palavras-chave: Educação Inclusiva. Inclusão. Educação Física. Deficiência Física.
« The Rainmakers » : le Service météorologique du Canada et la recherche sur la modification du temps dans l’après-guerre
Authors: Wallace Matthew L.
Published: March 2013

Le développement de la recherche sur la modification du temps est un élément central de l’évolution des sciences atmosphériques dans l’après-guerre au Canada. Nous mettons en valeur deux projets de recherche de grande envergure en Alberta et au Québec, dans le contexte d’un déplacement des études sur la modification du temps du laboratoire vers le terrain dans les années 1950 et 1960. Par ce biais, nous montrons comment les milieux naturel, économique, social et politique d’une région sont déterminants pour l’évolution du SMC et des sciences atmosphériques au Canada, deux éléments largement absents de l’historiographie des sciences au Canada. Les travaux sur la modification du temps mettent en évidence les liens avec la sphère politique, la fonction publique canadienne, la communauté scientifique et le secteur privé. Nous caractérisons ainsi les rapports de force dominants qui permettent au SMC de développer, à l’interne et à l’externe, une capacité scientifique au pays. En revanche, cette position du SMC, en tant que « service » gouvernemental déterminé par le mandat précis, accorde une marge de manoeuvre limitée au déroulement de cette recherche.
Science gouvernementale et nation building : Parcs Canada et la réinterprétation des territorialités locales
Authors: Craig-Dupont Olivier
Published: March 2013

Ce texte analyse l’histoire de création du parc national de la Mauricie au Québec dans les années 1970. Il explore notamment le rôle que joue la science de l’écologie dans la mise en place d’une représentation idéalisée de la nature dite « sauvage » des parcs nationaux canadiens sur le territoire mauricien. Selon le discours officiel de l’agence Parcs Canada, ce parc vise en effet à protéger un exemple de la « nature sauvage des grandes forêts du Bouclier canadien ». Or, notre histoire révèle toutefois des forêts profondément marquées par une activité humaine séculaire faite de chasse, de pêche et de foresterie. Dès lors, comment l’agence fédérale Parcs Canada réussit-elle à créer sur ces paysages humanisés une « aire naturelle représentative d’intérêt canadien »? La science de l’écologie permet cette transformation de la territorialité mauricienne. Par l’entremise d’inventaires, de cartes écosystémiques et de plans directeurs qui mettent l’accent sur les composantes naturelles du lieu – mais qui font abstraction de son histoire humaine –, Parcs Canada réussit à concrétiser matériellement et symboliquement sur le territoire de la province l’idéal de nature sauvage des parcs nationaux canadiens. Partant de la thèse de Suzanne Zeller (1988), notre histoire montre ainsi que la science servît à soutenir, toujours en 1970, les entreprises de nation-building de l’État canadien.
La courbe de Phillips : temps d’arbitrage et/ou arbitrage de temps
Authors: Gbaguidi David
Published: March 2013

La relation d’arbitrage inflation-activité réelle a progressivement retenu l’attention des chercheurs depuis l’étude de Phillips (1958). Pourtant, même si, dans le nouveau cadre keynésien d’analyse (NKPC), une quasi-résurrection de la courbe de Phillips a été entrevue, de nombreux aspects de la modélisation restent sujets à controverses dans la littérature actuelle. L’une des principales sources des remises en question du socle NKPC demeure celle associée à la prise en compte des anticipations des agents dans les rouages, à la fois théoriques et empiriques, de la réflexion. Partant de ce constat, cette revue de la littérature propose une synthèse des principaux résultats issus de l’introduction des anticipations dans les récentes modélisations de cette fameuse passerelle entre les sphères nominale et réelle du système économique. L’objectif est de restituer une synthèse des discours classique, monétariste et keynésien autour du thème de l’arbitrage, d’examiner les termes dans lesquels celui-ci est formulé, et de poser les jalons d’une évaluation de sa perméabilité aux débats plus largement « idéologiques » qui agitent l’ensemble de la profession.
La Société canadienne de science économique, une cinquantenaire à la croisée des chemins : 1960-2010
Authors: Dupré Ruth
Published: March 2013

En 2010, la Société canadienne de science économique (SCSE) célébrait son 50e anniversaire. Première association d’économistes au Canada, elle fut créée en octobre 1960 dans le but de regrouper les économistes canadiens de langue française et de promouvoir l’avancement de la science économique.

Cet article retrace l’histoire de la SCSE au moyen de trois sources d’information : le contenu des programmes de tous ses congrès annuels de 1960 à 2009, les documents d’archives de l’association et une série d’entrevues auprès de huit de ses anciens présidents.

Cette histoire peut se décliner en trois phases : une affaire de famille dans les années soixante; une communauté scientifique conventionnelle à partir de la seconde moitié des années soixante-dix; puis, dans les années deux mille, une association qui semble se chercher une nouvelle identité face à l’internationalisation des départements québécois d’économie et face à la prolifération des regroupements spécialisés à l’intérieur de la science économique.
Brief Periods of Sunshine: A History of the Canadian Government’s Attempt to Build a Solar Heating Industry, 1974-1983
Authors: Trim Henry
Published: March 2013

In the 1970s a worldwide energy crisis wracked Canada. Searching for ways to provide energy for Canada’s future, the Canadian government encouraged the development of a new technology: solar heating. The political and economic needs of the Trudeau government and Department of Energy, Mines, and Resources dominated the Canadian solar heating industry from its inception in 1978 until its demise in 1983. Partisan politics, however, were not the only important influence on solar energy in Canada. Technologies of simulation and prediction, as well as the Canadian government’s adherence to the ideology of objectivity, also shaped the history of solar heating in Canada. By analyzing the role of simulation, “objectivity,” and political power in the rise and fall of the solar industry, this essay hopes to illuminate the importance of government in the Canadian history of technology and begin to provide a history of Canadian solar technology and industry.
The Science of Territorial Domination in General Haldimand’s Defence of Quebec, 1778-1783
Authors: Gibson Sarah Katherine
Published: March 2013

In General Haldimand’s little-studied administration of Quebec during the American Revolutionary War, military strategy depended upon gathering information about the natural environment. Haldimand preserved Quebec for the British not by force, but by applying continental modes of territorial domination. Rather than secure the St. Lawrence Valley in an intimidating show of military force, Haldimand sought to secure the vitality of the fur trade along the Great Lakes corridor. This endeavor required Haldimand to look for the natural laws that created unity out of the social and geographic territory he had to defend, and to protect the most vital links: the economic currents and the transportation system. Thus, the Royal Engineers took precedence over other military officers as they collected a large body of information about the natural environment of the Great Lakes region. They drew maps, sounded bodies of water, and made meteorological observations, turning pleasant bays into safe harbors. The knowledge gathered replaced Mississaugan perspectives of the land, revised French information and set the agenda for Loyalist settlement in the region. This paper however, focuses upon Haldimand’s role in applying continental attitudes towards the landscape that helped solidify the link between natural history and imperialism of late-18th century Britain.
État et contrôle de la sexualité reproductive : l’exemple des politiques eugénistes dans les démocraties libérales (Suisse, Suède et Royaume-Uni)1
Authors: Mottier Véronique
Published: March 2013

Cet article examine un domaine spécifique de politique en matière de sexualité : les mesures eugénistes que plusieurs démocraties libérales ont mises en pratique entre les années 1920 et les années 1960. Plus précisément, la discussion des trajectoires politiques de mesures comme les stérilisations eugénistes en Suisse, en Suède et au Royaume-Uni servira de base pour une réflexion théorique sur le rôle de l’État dans la régulation et la surveillance de la sexualité reproductive, des pratiques sexuelles et des identités sexuelles de ses citoyennes et citoyens. L’analyse des liens entre la sexualité, la sphère politique et l’État m’amènera ensuite à problématiser la notion d’État. En effet, premièrement, les exemples de mesures eugénistes concrètes révèlent que l’action étatique dans ce domaine n’a pas toujours été cohérente, ni homogène. Elle s’est caractérisée au contraire par des interventions souvent non systématiques, voir contradictoires. Deuxièmement, j’argumenterai que les mesures eugénistes se sont développées aussi bien sous contrôle étatique qu’en dehors de l’État, voire contre ce dernier. D’une part, des acteurs paraétatiques comme des cliniques psychiatriques universitaires ou des autorités politiques locales ont joué un rôle clé dans la régulation eugéniste de la sexualité. D’autre part, des acteurs importants du point de vue de l’application de stérilisations eugénistes, comme les associations de médecins, se sont parfois politiquement opposés à l’élaboration de politiques publiques dans ce domaine, considérant l’intervention étatique comme une restriction de pratiques qui étaient déjà monnaie courante. Je suggérerai que la présence ou l’absence de politiques publiques eugénistes constitue de ce fait un indicateur insatisfaisant pour juger de l’importance de pratiques eugénistes dans des contextes nationaux spécifiques. J’argumenterai que saisir la complexité de cette dynamique politique nécessite une prise en compte des manières dont les politiques publiques et les systèmes étatiques sont, de manière plus générale, à leur tour structurés par des rapports de pouvoir autour de la sexualité, ainsi qu’autour d’autres marqueurs identitaires comme le genre, la « race », les classes sociales ou les handicaps physiques et mentaux.
Knowledge, attitudes and practices regarding HIV/AIDS among male high school students in Lao People's Democratic Republic
Authors: Thanavanh Bounbouly , Harun‐Or‐Rashid Md. , Kasuya Hideki , Sakamoto Junichi
Published: March 2013

Introduction

Inadequate knowledge, negative attitudes and risky practices are major hindrances to preventing the spread of HIV. This study aimed to assess HIV‐related knowledge, attitudes and practices (KAPs) of high school students in Lao People's Democratic Republic (PDR).

Methods

A cross‐sectional study on unmarried male students aged between 16 and 19 years old was undertaken in 2010 to evaluate their KAPs. We selected 300 eligible grade VII students through systematic random sampling from different high schools in one province of Lao PDR.

Results

The majority of students surveyed were aware that HIV can be transmitted by sexual intercourse (97.7%), from mother to child (88.3%) and through sharing needles or syringes (92.0%). Misconceptions about transmission of HIV were observed among 59.3% to 74.3% of respondents. Positive attitudes towards HIV/AIDS were observed among 55.7% of respondents. Nearly half of the surveyed students (45.3%) said that they would be willing to continue studying in a school with HIV‐positive friends, and 124 (41.3%) said they would continue attending a school with HIV‐positive teachers. Ninety‐four (31.3%) students had a history of sexual intercourse, and 70.2% of these students had used a condom. However, only 43.9% said they used condoms consistently. Students with medium and high levels of knowledge were 4.3 (95% CI=2.1–9.0, P<0.001) and 13.3 (95% CI=6.5–27.4, P<0.001) times more likely to display positive attitudes towards people living with HIV. Similarly, safe practices related to safe sex were also observed among students with medium (OR=2.8, 95% CI=0.9–8.8, P=0.069) and high levels of knowledge (OR=1.9, 95% CI=0.6–6.2, P=0.284). More than three‐quarters of students mentioned television and radio as major sources of information on HIV/AIDS.

Conclusions

Despite adequate knowledge about HIV/AIDS among the school students, misconceptions about routes of transmission were found. Negative attitudes to HIV/AIDS and risky practices were also present. Educational programmes with specific interventions are recommended to increase KAPs and to prevent new HIV infections among students in Lao PDR.
Sex ratio, reproduction, and growth of the gilthead sea bream, Sparus aurata (Pisces: Sparidae), in the Gulf of Gabes, Tunisia
Authors: Hadj-Taieb Aymen , Ghorbel Mohamed , Hadj-Hamida Nader Ben , Jarboui Othman
Published: March 2013

Samples (N = 1065) of the gilthead seabream, Sparus aurata, were collected in the Gulf of Gabes (Tunisia) from March 2008 to February 2010. This species is a protandric hermaphrodite. Total length (TL) ranged from 10.10 to 35.00 cm and the number of males to each female was 1.18:1. The reproductive season extended from October to February and maximum spawning activity occurred from December to January. The size at which 50% of the males reached maturity was 17.63 ± 0.28 cm TL and the size at which 50% of males transformed into females was 18.75 ± 0.19 cm TL. The length-weight relationship for all individuals was described by the following parameters: a = 0.0107 and b = 3.0797. Age of fish ranged from 0 to 8 years. Estimates of the von Bertalanffy growth parameters for the whole sample were: L∞= 38.28 cm, k = 0.202 year–1, and t0 = –1.888 years.
Influence of the combined disposal of sewage and brine on meiofauna
Authors: Riera Rodrigo , Tuya Fernando , Sacramento Alicia , Ramos Eva , Monterroso Óscar , Rodríguez Myriam
Published: March 2013

Confluence of anthropogenic influences is common in coastal areas (e.g., disposal of different pollutants like industrial and domestic sewage, brine, etc.). In this study we assessed whether the combined disposal of domestic sewage and brine altered patterns in the abundance and assemblage structure of subtidal meiofauna inhabiting sandy seabeds. Samples were collected in May 2008 and January 2009 at varying distances (0, 15, and 30 m) from the discharge point. Meiofaunal abundances were consistently larger at 0 m (1663.05 ± 1076.86 ind 10 cm–2, mean ± standard error) than at 15 m (471.21 ± 307.97 ind 10 cm–2) and 30 m (316.50 ± 256.85 ind 10 cm–2) from the discharge outfall. This pattern was particularly accentuated for nematodes. Proximity to the discharge point also altered patterns in meiofaunal assemblage structure, though temporal shifts in the sedimentary composition also contributed to explain differences in the meiofaunal assemblage structure. As a result, meiofauna may be a reliable tool for monitoring studies of the combined disposal of sewage and brine as long as potential confounding factors (here temporal changes in grain size composition) are considered.
Effectiveness of aluminosilicate-based products for detoxification of aflatoxin-contaminated diets for juvenile Pacific white shrimp, Litopenaeus vannamei
Authors: García-Pérez Oscar Daniel , Tapia-Salazar Mireya , Nieto-López Martha Guadalupe , Villarreal-Cavazos David , Cruz-Suárez Lucía Elizabeth , Ricque-Marie Denis
Published: March 2013

The safety and effectiveness of four aluminosilicate-based products (Novasil Plus, Zeolex Extra, Mycofix Select, and Fixat) were tested for 42 days on juvenile Pacific white shrimp, Litopenaeus vannamei, fed diets containing corn grains that had been previously inoculated with Aspergillus parasiticus and then sterilized. Two control diets, one uncontaminated and another contaminated with the contaminated corn grain, were elaborated to contain a final concentration of 0 and 75 μg kg–1 total aflatoxins. Both diets were formulated to contain 38% crude protein and 8% lipids. Eight more diets were manufactured from the previous two to contain each of the test products at inclusion levels of 2.5 to 5.0 g kg–1, in accordance with the inclusion level recommended by the manufacturer. Mycofix Select and Fixat inclusion improved diet stability (12–16%). Water absorption capacity in the diets increased (from 2% to 17%) due to the supplementation of aluminosilicates. Feeding aflatoxin-contaminated diets to Pacific white shrimp resulted in lower feed intake and weight gain without affecting the feed conversion ratio, nitrogen retention, and survival. Feeding the uncontaminated diets supplemented with Zeolex Extra, Mycofix Select, and Fixat resulted in a slight reduction in feed intake without affecting growth rate, nitrogen retention, or survival. Conversely, the inclusion of Novasil Plus in the uncontaminated diet did not affect feed intake and an 8% growth rate improval was observed. Three of the tested products failed to provide complete restoration of feed consumption and shrimp growth rate when added to the aflatoxin-contaminated diet.
In Vivo Imaging and Biochemical Characterization of Protease Function Using Fluorescent Activity‐Based Probes
Authors: Edgington Laura E. , Bogyo Matthew
Published: March 2013

Activity‐based probes (ABPs) are reactive small molecules that covalently bind to active enzymes. When tagged with a fluorophore, ABPs serve as powerful tools to investigate enzymatic activity across a wide variety of applications. In this article, detailed protocols are provided for using fluorescent ABPs to biochemically characterize the activity of proteases in vitro. Furthermore, descriptions are provided of how these probes can be applied to image protease activity in live animals and tissues along with subsequent analysis by histology, flow cytometry, and SDS‐PAGE. Curr. Protoc. Chem. Biol. 5:25‐44 © 2013 by John Wiley & Sons, Inc.
Celastrus orbiculatus Thunb. Decreases Athero‐Susceptibility in Lipoproteins and the Aorta of Guinea Pigs Fed High Fat Diet
Authors: Zhang Ying , Si Yanhong , Yao Shutong , Yang Nana , Song Guohua , Sang Hui , Zu Dandan , Xu Xin , Wang Jianhua , Qin Shucun
Published: March 2013

Celastrus orbiculatus Thunb. (COT), a traditional Chinese herb, has anti‐inflammatory and anti‐oxidative properties. In this study, we examined the protective effect of COT on the initiation of atherosclerosis induced by high fat diet and explored the underlying mechanisms. We established guinea pig models of hyperlipidemia and treated them with three dosages of COT or 20 mg/kg/d simvastatin (a positive control drug) for 8 weeks. Plasma lipid analysis indicated that COT decreased total cholesterol (TC), non‐high‐density lipoprotein cholesterol (non‐HDL‐C), triglyceride (TG), apolipoprotein B100 (apoB100) and apolipoprotein E (apoE) levels and increased high density lipoprotein cholesterol (HDL‐C) level. The analysis of the hepatic gene involving cholesterol metabolism by quantitative real‐time PCR revealed that COT upregulated the mRNA abundance of LDL receptor (LDL‐R), scavenger receptor class B type 1 (SR‐B1), cholesterol 7α‐hydroxylase A1 (CYP7A1) and the 3‐hydroxy‐3‐methyl‐glutaryl‐CoA reductase (HMGCR). Oil red O staining showed COT significantly reduced lipid deposition in the arterial wall. Moreover, ELISA assay revealed COT lowered the levels of C‐reactive protein (CRP), interleukin‐6 (IL‐6), and tumor necrosis factor‐α (TNF‐α) in plasma. Meanwhile, the level of Nitric oxide (NO) in plasma was increased by COT. Immunohistochemistry and Western blot analysis showed the expression of CD68 and active NF‐kB p65 proteins in the arterial wall was decreased by COT. The content of Malondialdehyde (MDA) and activity of Superoxide dismutase (SOD) in plasma were determined and the data indicated COT suppressed oxidative stress reaction. These results reveal that administration of COT decreases athero‐susceptibility through lowering plasma lipid, attenuating inflammation, and suppressing oxidative stress in guinea pig fed high fat diet.