Incidence de pluies exceptionnelles sur un aquifère hétérogène côtier (M’nasra, Maroc)

Les eaux souterraines qui représentent les seules ressources en eau de la M’nasra côtière, sont minéralisées : intrusion marine, évaporation, recyclage des eaux d’irrigation chargées en sels et l’utilisation abusive des engrais. L’évolution spatio-temporelle de la pollution nitrique de cette nappe phréatique a été suivie sur 159 puits, objective en trois périodes de campagne éclatées : 2003, 2007 et 2010 qui inclue une période exceptionnellement pluvieuses. Une comparaison par apport à l’état de la nappe en 1993, date de début de la surexploitation des eaux souterraines, a été faite. Les suivis ont montré qu’à la suite des Pluiesimportantes de la période de campagne 2009/2010, on a pu observer une dégradation de la qualité de la nappe aussi bien au niveau ponctuel qu’au niveau spatial, en particulier dans la partie Nord de la zone étudiée (aunord de la ligne de cordonnée Y = 430 000 m). Les résultats de cette étude sont présentés sous forme de cartes thématiques par le SIG.  Mots clés: Aquifère côtier, inondation, pollution nitrique, nappe phréatique, M’nasra, Maro

Multi-criteria evaluation of suitable sites for termite mounds construction in a tropical lowland

© 2019 Elsevier B.V. Termite mounds influence ecosystem heterogeneity and contribute to the stabilization of the system under global change. A number of environmental factors influence the distribution, height, diameter and designs of termite mounds but these factors are not only poorly understood, they cannot be extrapolated for everywhere. In this study, we employed a ground based survey and Geographical Information System (GIS) technique to map 156 km 2 study area in Keffi, Nigeria. The aims were to (1) estimate the density and area covered by termite mounds, (2) sample and identify species types and how they are distributed, and (3) use five environmental factors (elevation, geology, surface water drainage, land use/land cover and static water level) to model suitable sites for mounds construction. A total of 361 mounds were mapped representing a density of about 0.8 mounds ha −1 and covering only about 0.31% of the studied area. Next, the effect of the five chosen environmental factors on the geographic distribution, life status, height and diameter of mounds and species diversity were analysed and their relationships plotted in pairwise comparison matrices using the Saaty's Analytical Hierarchy Process. Normalized rates for classes in each factor and corresponding weights were computed and aggregated using the Weighted Linear Combination method. The result depicted that moderate to low elevation (270–330 m amsl), rock cover types that are more susceptible to weathering (schist), cultivated areas and shallow water table zones are most favourable for termites to build mounds. The result obtained in this study shows a promising correlation between the environmental factors and termite mounds distribution. The proposed model can easily be replicated in a different but similar multi-land use and rock cover types

Screening Diabetic and Hypertensive Patients for Ocular Pathology using Telemedicine Technology in Rural West Virginia: A Retrospective Chart Review

Abstract: Purpose: There is a disparity between the number of people who need healthcare and availability of medical services in rural areas. This paper describes the experience of using telemedicine technologies for ophthalmologic evaluation in diabetic and hypertensive patients presenting to a community health center in rural West Virginia. Methods: A registered nurse at a community health center in McDowell County, WV was trained to use a retinal camera to capture high-resolution digital images of the retina. Patients with diabetes or hypertension were screened during their routine primary care visits. Retinal photos were transmitted to an ophthalmologist for review and reports from the screenings were returned with instruction for follow-up care or specialist referral when indicated. Findings: A retrospective chart review of 643 patients with diabetes or hypertension who were screened for ocular problems from October 2003 to December 2009 was completed. 44.8% of patients who were screened in the primary care center were identified as having 1 of 34 types of eye pathology that were previously unknown,of which 33% of patients were recommended to seek prompt attention by a retina consultant or glaucoma specialist for suspected ocular pathology. Conclusions: Our review demonstrates the actual benefits of telemedicine in the effective screening of diabetic and hypertensive patients for eye pathology,and our experience suggests that using distance medicine and telemedicine technologies is valuable for screening rural populations

Analysis of oxy-fuel combustion power cycle utilizing a pressurized coal combustor

Growing concerns over greenhouse gas emissions have driven extensive research into new power generation cycles that enable carbon dioxide capture and sequestration. In this regard, oxy-fuel combustion is a promising new technology in which fuels are burned in an environment of oxygen and recycled combustion gases. In this paper, an oxy-fuel combustion power cycle that utilizes a pressurized coal combustor is analyzed. We show that this approach recovers more thermal energy from the flue gases because the elevated flue gas pressure raises the dew point and the available latent enthalpy in the flue gases. The high-pressure water-condensing flue gas thermal energy recovery system reduces steam bleeding which is typically used in conventional steam cycles and enables the cycle to achieve higher efficiency. The pressurized combustion process provides the purification and compression unit with a concentrated carbon dioxide stream. For the purpose of our analysis, a flue gas purification and compression process including de-SO[subscript x], de-NO[subscript x], and low temperature flash unit is examined. We compare a case in which the combustor operates at 1.1 bars with a base case in which the combustor operates at 10 bars. Results show nearly 3% point increase in the net efficiency for the latter case.Aspen Technology, Inc.Thermoflow Inc

Ion Beam Sputtering Yield Measurements by Quartz Crystal Microbalance

Quartz-crystal microbalance (QCM) has been used as a sensitive device for the measurement of small mass changes for a long ago. In fact, using QCM we can measure the differential sputtering yield profile of a material, over a hemisphere above the target, very precisely. The sputtering yield depends on properties of both the incident ions (energy, mass, and incidence angle) and the target (mass, surface binding energy, surface topography, and even the crystal orientation). In our present study, we used a highly sensitive QCM to detect the mass change of the electrode material (gold and silver) through oscillations and calculated the corresponding sputtering yields. We used two types of ions, e.g, He and Ar, in an Ultra High Vacuum (UHV) chamber using the NTI ion gun as the ion source. Our experimental observation shows significantly higher sputtering yield values than that of the theoretically calculated ones, using SRIM simulations. In addition, we observed a significant reduction in the sputtering yield values with time, for a constant ion energy bombardment. Similarly, atomic force microscopy (AFM) study shows a significant reduction in the surface roughness values for a longer period of ion bombardment. These observations suggest that surface topography affects significantly the sputtering yield values. In the presentation the details of the disparities between experimental and the modeling will be discussed

Patient-specific, mechanistic models of tumor growth incorporating artificial intelligence and big data

Despite the remarkable advances in cancer diagnosis, treatment, and management that have occurred over the past decade, malignant tumors remain a major public health problem. Further progress in combating cancer may be enabled by personalizing the delivery of therapies according to the predicted response for each individual patient. The design of personalized therapies requires patient-specific information integrated into an appropriate mathematical model of tumor response. A fundamental barrier to realizing this paradigm is the current lack of a rigorous, yet practical, mathematical theory of tumor initiation, development, invasion, and response to therapy. In this review, we begin by providing an overview of different approaches to modeling tumor growth and treatment, including mechanistic as well as data-driven models based on ``big data" and artificial intelligence. Next, we present illustrative examples of mathematical models manifesting their utility and discussing the limitations of stand-alone mechanistic and data-driven models. We further discuss the potential of mechanistic models for not only predicting, but also optimizing response to therapy on a patient-specific basis. We then discuss current efforts and future possibilities to integrate mechanistic and data-driven models. We conclude by proposing five fundamental challenges that must be addressed to fully realize personalized care for cancer patients driven by computational models

The Role of Surface Roughness on Ion Sputtering Yield Measurements

Ion sputtering is the removal of surface atoms or molecules in a solid under energetic ion irradiation. This technique is promising for its applications in material modification and characterization. Sputtering yield, the average number of atoms removed from a sample per incident ion, is a crucial parameter in material modification. In the present study, a quartz crystal microbalance was used within an ultra-high vacuum chamber (10E-8 torr) to measure the sputtering yield of gold. An NTI-1401 ion gun was used to bombard argon and helium ions onto a gold sample. The argon and helium ions used ranged in energy from 100 – 5000 eV. Theoretical sputtering yield values were determined through simulation with Stopping and Range of Ions in Matter (SRIM) software and compared with experimentally measured values. The experimental values show a significantly higher sputtering yield for gold than that of the SRIM values; however they followed the same trend. Another observation was that for a constant ion energy bombardment the sputtering yield decreased with time. An atomic force microscopy (AFM) was performed before and after sputtering. The AFM showed that the surface of the sample became smoother after a period of ion bombardment. These observations suggest that surface topography significantly affects the sputtering yield values. The reasoning behind the discrepancy between experimental and SRIM sputtering yield values will be discussed

A Hybrid Approach for the Recommendation of Scholarly Journals

© 2020 IEEE. The increasing number of scholarlyjournals have made it difficult for authors to select the most suitable journal that publishes their research. Existing search systems that recommend journals for manuscript submission are either based on author 's profile, bibliographic data or the copublication network. These approaches are not useful for beginner researchers who have no publication records or for those who are interested in new research domains. The present work proposes a hybrid approach that combines clustering and document similarity for the recommendation of scholarly venues. The proposal was evaluated both objectively and subjectively using domain experts. The results of mean average precision (0.84) and normalized discounted cumulative gain (0.89) shows positive recommendations made by the proposed approach