2,637 research outputs found
Community Perceptions of the Environmental Remediation Effort in the Milwaukee River Estuary
The Environmental Protection Agency (EPA), Wisconsin Department of Natural Resources (DNR), and Milwaukee County Parks Department have been working on an environmental remediation project that seeks to remove chemical contaminants and pollution from the Milwaukee River. The purpose of this research is to discover community member’s perceptions on the quality and safety of the Milwaukee River, and determine whether their perspectives on safe and desirable uses of the river differ from those of the organizations overseeing the Great Lake Legacy Act (GLLA) project. The results from this study show that the communities in the project area believe that the quality of the river has improved but it is still unsafe in some ways. This study shows that understanding the perceptions about quality, safety and uses of the river can improve the relationship between remediation organizations and the affected community.Ope
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A record of abundance of fish teeth and shark denticles during the Pleistocene
As many marine species face dwindling populations due to the effects of climate change, it is vital to gain crucial information on what this means for the future of these organisms and their surrounding ecosystems. In order to gain insight to what ocean ecosystems might look like with shifting climate variability, we can look to the past. The goal of this project is to produce a two-million-year record of abundance of pelagic fish and sharks in the waters off Cape Town, South Africa. A Ichthyolith Accumulation Rate (IAR) was established to identify fish and shark production over the span of 2 million years. Results from this study show significant fluctuations of IAR, potentially contributing to the glacial-interglacial cycles that characterize the Pleistocene. When compared to complementary data, IAR data from this site is significantly higher compared to other subtropical regions. This increased IAR may be attributed to the behavior of the Agulhas Current that flows around the southern end of the Cape of Good Hope. This project aims to expand the geological history of fish abundances, providing baseline data to fill gaps in knowledge and guide future management efforts.See the storymap created for this project here: https://storymaps.arcgis.com/stories/9e02851bc352487db26e5c4aa9fed27
The Place of Child Labour in the Regional Integration Discourse within ECOWAS: An Analysis of the Existing Legal Instruments and Responses
Purpose – This study aims to examine the lingering issue of the violation of child rights that occurs through the practice of child labour within the Economic Community of West Africa (ECOWAS) and the ongoing discourse on regional integration.Design methodology/approach – A textual analysis is conducted and a deconstruction of the argument that has been put forward to sustain the existence of practical actions at regional and sub-regional levels in providing an adequate legal response to the problem of child rights violation through child labour within ECOWAS.Findings – There is evidence of inequity in legal responses to validate the discourse on regional integration in that enduring human rights violations in general and child rights violations, in particular, cannot consolidate regional integration perspectives.Originality/Values – The study reveals that Regional integration is a holistic endeavour. It does not rest on it must necessarily encompass the question of human rights promotion and protection. Unfortunately, the increasing literature on regional integration has often omitted human rights as a pillar of successful regional integration
Numerical modelling of unsaturated flow in vertical and inclined waste rock layers using the seep/w model
Conventional disposal of waste rock results in the construction of benches with interbedded fine and coarse layers dipping at the angle of repose. The waste rock benches are typically 20-meters in height and are constructed in a vertical sequence to form waste rock dumps commonly greater than 100-meters high. The interbedded structure influences the flow pathways for infiltration water within the waste rock profile. Preferential flow pathways develop when one material becomes more conductive than the surrounding material. The flow of meteoric waters through the interbedded waste rock structure is difficult to describe since the dumps are constructed above natural topography and are generally unsaturated.
Two previous research studies were undertaken at the University of Saskatchewan to study end dumped waste rock piles and the relationship to preferential flow for unsaturated conditions. The first study was conducted during the excavation of a large waste rock pile at Golden Sunlight Mine in Montana (Herasymuik, 1996). Field observations showed that the waste rock pile consisted of steeply dipping fine and coarse-grained layers. The results of further laboratory analysis indicated the potential for preferential flow through the fine-grained material under conditions with negative pore-water pressures and unsaturated flow.
The second study investigated the mechanism for preferential flow in vertically layered, unsaturated soil systems (Newman, 1999). The investigation included a vertical two-layer column study and a subsequent numerical modelling program showing that water prefers to flow in the finer-grained material. The preferential flow path was determined to be a function of the applied surface flux rates and the unsaturated hydraulic conductivity of the fine-grained material layer.
A numerical modelling program to evaluate preferential flow was conducted for the present study in an inclined four-layer system consisting of alternating fine and coarse-grained waste rock. The numerical modelling program was undertaken using the commercial seepage software package, Seep/W, that is commonly used by geotechnical engineers. The result obtained using Seep/W showed preferential flow to occur in the fine-grained layer. However, difficulties with respect to convergence under low flow conditions with steep hydraulic conductivity functions were encountered.
A comprehensive sensitivity analysis was completed to investigate the factors that influence convergence in the Seep/W model including: convergence criteria, mesh design and material properties. It was found that the hydraulic conductivity function used for the coarse-grained material was the most important factor. The problem of the steep slope for the hydraulic conductivity function specified for the coarse-grained material was solved by progressively decreasing the slope of the hydraulic conductivity function at 10-8 m/s (for applied fluxes of 10-7 m/s or less). The sensitivity analysis showed that the manipulation of the hydraulic conductivity function had insignificant changes in the flux distribution between the waste rock layers and great significance for achieving convergence. Based on the discoveries of the sensitivity analysis, a 20-meter high multi-layer waste rock profile inclined at 50Âş with an applied flux of 7.7e10-9 m/s equal to the annual precipitation at the Golden Sunlight Mine was successfully simulated. A parametric study was subsequently conducted for an applied flux rate of 10-5 m/s for slope heights of 1-meter to 20 meters with slope angles varying between 45Âş and 90Âş. The parametric study demonstrated that flow in a multi-layered waste rock dump is a function of inclination, contact length between the layers, and the coarse and fine-grained hydraulic properties for the waste rock. An alternative numerical modelling technique based on a modified Kisch solution was also used to investigate preferential flow. The Kisch method helped to verify and simplify the numerical problem as well as to illustrate the mechanics of preferential flow in a two-layered system.
In general, commercial seepage modeling packages are powerful and useful tools that are designed to adequately accommodate a wide range of geotechnical problems. The results of this research study indicate that Seep/W may not be the best-suited tool to analyze unsaturated seepage through sloped waste rock layers. However, numerical modelling is a process and working through the process helps to enhance engineering judgment. The Seep/W model provided an adequate solution for a simplified simulation of unsaturated seepage through waste rock layers. The modified Kisch solution independently verified the solution and provided additional confidence for the results of Seep/W model
La carrera administrativa en las superintendencias
La temática de la investigaciĂłn hace parte del derecho administrativo en Colombia, especĂficamente al área del derecho administrativo laboral, y dentro de Ă©ste contexto, desarrolla el sistema especĂfico de carrera administrativa para las superintendencias. De acuerdo con las guĂas tutoriales que la universidad realiza en las cátedras de investigaciĂłn y metodologĂa, se planteĂł inicialmente el anteproyecto del trabajo, y con posterioridad, se consolidĂł el proyecto de investigaciĂłn. La investigaciĂłn se centra en el estudio legal y jurisprudencial para posibilitar una construcciĂłn teĂłrica respecto de un tema con escasa o nula producciĂłn bibliográfica
Evaluation De L’activité Acaricide De Quelques Biopesticides Sur L’acarien Tarsonème, Polyphagotarsonemus Latus Banks (Acari : Tarsonemidae) Infestant L’aubergine Gboma (Solanum Macrocarpon L.) Au Sud-Bénin
L’acarien tarsonème, Polyphagotarsonemus latus Banks, est un important ravageur de l’aubergine Gboma (Solanum macrocarpon L.), un légume-feuille de grande consommation au Bénin. La gestion de ce ravageur repose fondamentalement sur la lutte chimique avec toutes ses conséquences sur la santé et sur l’environnement ; d’où la nécessité de rechercher des solutions alternatives. Ainsi, la performance de trois biopesticides notamment huile de neem (Azadirachta indica A. Juss), extraits aqueux de hyptis (Hyptis suaveolens (L.) Poit, et du faux basilic (Ocimum gratissimum L), a été testée sur les œufs et adultes de P. latus au laboratoire de paires avec celle de Acarius et Sunpyrifos, deux acaricides chimiques communément utilisés au Bénin. Aussi, leurs effets sur les densités de population du ravageur et la productivité du Gboma ont-ils été évalués en plein champ. Au laboratoire, les taux moyens d’éclosion des œufs ont varié significativement entre traitements, allant 36 ± 5% à 80 ± 5% (P < 0,0001). Le plus fort taux d’éclosion a été enregistré sur le témoin et hyptis tandis que le plus fort d’éclosion a été enregistré avec Acarius suivi du Sunpyrifos et de l’huile de neem. Les taux de mortalité des adultes de P. latus ont également varié significativement entre les différents traitements allant de 43 ± 2% à 100% (P < 0,0001). Les plus faibles mortalités ont été enregistrées sur le témoin suivi de hyptis tandis que les plus forts taux ont été enregistrés, avec les doubles-doses de Acarius, Sunpyrifos et de l’huile de neem. Au champ, les densités moyennes par feuille des stades mobiles de P. latus ont varié significativement entre traitements, allant de 5,37 ± 0,59 et 2,71 ± 0,37 individus (P < 0,0001) ; les densités les plus fortes ayant été enregistrées sur le témoin tandis qu’aucune différence statistique n’a été observée entre les cinq autres traitements. Les plus fortes productivités de Gboma (kg/4 m2 ) ont été enregistrées avec l’huile de neem (13,65 ± 2,13), Sunpyrifos (11,10 ± 1,66) et Acarius (10,76 ± 1,32). Il s’en déduit qu’en attendant des études complémentaires, l’huile de neem peut être recommandée comme alternative aux acaricides chimiques contre P. latus sur les parcelles de Gboma au Sud-Bénin.
The broad mite, Polyphagotarsonemus latus Banks is a key pest of the nightshade, commonly called Gboma eggplant (Solanum macrocarpon L.), a staple leafy vegetable in Benin. Management of this pest relies on chemical control despite its harmful environmental and sanitary impacts. It urgestherefore to search for alternative methods. In that respect, performances of some biopesticides including neem oil (Azadirachta indica A. Juss), aqueous extracts of Hyptis suaveolens (L.) Poit and of Ocimum gratissimum L. (clove basil), were tested on egg and adult stages of P. latus in laboratory in comparison to those of Acarius and Sunpyrifos, two chemical acaricides commonly used on vegetable farms in Southern Benin. In addition, their effects on the population densities of the pest and on the productivity of Gboma were evaluated in the field. In the laboratory, mean egg hatching rates varied significantly among treatments, ranging from 36 ± 5% to 80 ± 5% (P < 0,0001). The highest hatching rates were recorded with the control and hyptis treatments whereas the lowest hatching rates were recorded with Acarius followed by Sunpyrifos then neem oil treatments. Mortality rates of adult P. latus individuals also varied significantly among treatments, ranging from 43 ± 2% to 100% (P < 0,0001). The lowest mortality rates were recorded on the control followed by hyptis treatments whereas the highest mortalities were recorded with the double-doses of Acarius, Sunpyrifos and neem oil. In the field trials, mean densities of mobile stages of P. latus varied significantly among treatments, ranging from 5,37 ± 0,59 to 2,71 ± 0,37 individus (P < 0,0001). The highest densities were recorded on the control treatment whereas no significant differences were observed among the five other treatmentsThe highest productivities in fresh Gboma leaves on 4 m2 plot were recorded with neem oil (13.65 ± 2.13 kg), Sunpyrifos (11.1 ± 1.66 kg) and Acarius (10.76 ± 1.32 kg). Pending further studies, neem oil may be recommended as an alternative to chemical acaricides for the control of P. latus on Gboma plots in Southern Benin
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