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Search Results: 1 - 10 of 186684 matches for " Hédi Ben Ali "
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Required Lateral Inlet Pressure Head for Automated Subsurface Drip Irrigation Management
Moncef Hammami,Khemaies Zayani,Hédi Ben Ali
International Journal of Agronomy , 2013, DOI: 10.1155/2013/162354
Abstract: Subsurface drip irrigation (SDI) is one of the most promising irrigation systems. It is based on small and frequent water supplies. Because SDI emitters are buried, their discharges are dependent on the water status at the vicinity of the outlets. This paper was targeted to design the SDI laterals accounting for the soil water-retention characteristics and the roots water extraction. The proposed approach provides systematic triggering and cut-off of irrigation events based on fixed water suctions in the vadose zone. In doing so, the soil water content is maintained at an optimal threshold ascertaining the best plant growth. Knowing the soil water-retention curve, the appropriate water suction for the plant growth, and the emitter discharge-pressure head relationship, the developed method allows the computation of the required hydraulics of the lateral (e.g., inlet pressure head, inside diameter, etc.). The proposed approach is a helpful tool for best SDI systems design and appropriate water management. An illustrative example is presented for SDI laterals’ design on tomato crop. 1. Introduction In subsurface drip irrigation (SDI), water seeps from the buried emitters into the soil and spreads out in the vadose zone under the conjugate effect of capillary and gravity forces [1, 2]. Thus, SDI system allows the direct application of water to the rhizosphere maintaining dry the nonrooted topsoil. This pattern generates numerous advantages such as minimizing soil evaporation and then evapoconcentration phenomenon. The rationale is that SDI improves the water application uniformity, increases the laterals and emitters longevity, reduces the occurrence of soil-borne diseases, and allows the control of weeds infestation. Several field trials revealed relevant profits on managing SDI for crop production. Nevertheless, the appropriate depth of buried laterals remains debatable [3–6]. Comparing evaporation from surface and subsurface drip irrigation systems, Evett et al. [7] reported that 51?mm and 81?mm were saved with drip laterals buried at 15?cm and 30?cm, respectively. Neelam and Rajput [1] recorded maximum onion yield (25.7?t?ha?1) with drip laterals buried at 10?cm. According to these authors, the maximum drainage occurred when drip laterals are laid at 30?cm depth. On the other hand, numerous studies were devoted to the analysis of the effect of the soil properties on the SDI emitters discharge and water distribution uniformity [8–10]. The analytical approach proposed by Sinobas et al. [2] predicts reasonably well the soil water suction and the pressure
Beneficial Effect of an Oral Antioxidant Supplementation (Fertimax2) on IVF-ICSI Outcomes: A Preliminary Clinical Study  [PDF]
Olfa Kacem, Meriem Harzallah, Chekib Zedini, Ines Zidi, Sawsen Meddeb, Meriem Fékih, Habib Saidi, Anouar Chaib, Sassi Boughizane, Habib Ben Ali, Mohamad Bibi, Ali Saad, Hédi Khairi, Mounir Ajina
Advances in Reproductive Sciences (ARSci) , 2014, DOI: 10.4236/arsci.2014.23006
Abstract: Background: Considerable evidence points towards a significant role of oxidative stress (OS) in the pathogenesis of sperm dysfunction. OS as a result of an inappropriate balance between oxidants and antioxidants in the semen can cause DNA damage and lipid peroxidation leading to failure of conception, miscarriage or potentially even childhood cancer. The objective of this study was to investigate whether a male antioxidant therapy can improve semen parameters and the results of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). Methods: A total of forty eight infertile couples were considered. Male participants were administrated Fertimax2 antioxidant treatment for at least two months prior to their partner’s IVF-ICSI cycle. Sperm parameters (volume, concentration, progressive motility) and the IVF-ICSI outcomes were compared before and after the antioxidant treatment. The primary outcome measures were oocyte fertilization, cleavage and good embryo quality rates; the secondary outcomes were biochemical pregnancies, clinical pregnancies and implantation rates. Results: The principal finding that emerged from this study was that antioxidant therapy resulted in significant improvements in fertilization (p = 00.2), cleavage (p = 0.004) and good-embryo quality (p = 0.002) rates accompanied by a marked increase in clinical pregnancy (18.7% versus 2.5%) and implantation (11.8% versus 1.02%) rates. No significant changes in routine sperm parameters were observed. Conclusion: The Fertimax2 antioxidant therapy appears to influence favorably chances of conception in couples undergoing assisted reproduction treatment (ART).
Mechanical Impedance of Cerebral Material  [PDF]
Moez Chakroun, Hédi Ben Ghozlen
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.33037
Abstract: The tentative variation of the mechanical impedance, of a cylindrical sample of cerebral material, has been achieved by Vibrometer Laser according to the frequency. The studied matter is supposed homogeneous, isotropic and stationary. A multilayered mechanical model has been associated to the studied sample to simulate its vibration. The theoretical expression of mechanical impedance has been determined while taking the mechanical/electric analogy as a basis. A good adjustment of theoretical model parameters permitted us to have a good agreement theory/experience of the mechanical impedance variation according to the sample vibration frequency.
Surface acoustic waves in two dimensional phononic crystal with anisotropic inclusions
Ketata H.,Ghozlen M. Hédi Ben
EPJ Web of Conferences , 2012, DOI: 10.1051/epjconf/20122900043
Abstract: An analysis is given to the band structure of the two dimensional solid phononic crystal considered as a semi infinite medium. The lattice includes an array of elastic anisotropic materials with different shapes embedded in a uniform matrix. For illustration two kinds of phononic materials are assumed. A particular attention is devoted to the computational procedure which is mainly based on the plane wave expansion (PWE) method. It has been adapted to Matlab environment. Numerical calculations of the dispersion curves have been achieved by introducing particular functions which transform motion equations into an Eigen value problem. Significant improvements are obtained by increasing reasonably the number of Fourier components even when a large elastic mismatch is assumed. Such approach can be generalized to different types of symmetry and permit new physical properties as piezoelectricity to be added. The actual semi infinite phononic structure with a free surface has been shown to support surface acoustic waves (SAW). The obtained dispersion curves reveal band gaps in the SAW branches. It has been found that the influence, of the filling factor and anisotropy on their band gaps, is different from that of bulk waves.
Sparse Distributed Learning Based on Diffusion Adaptation
Paolo Di Lorenzo,Ali H. Sayed
Computer Science , 2012, DOI: 10.1109/TSP.2012.2232663
Abstract: This article proposes diffusion LMS strategies for distributed estimation over adaptive networks that are able to exploit sparsity in the underlying system model. The approach relies on convex regularization, common in compressive sensing, to enhance the detection of sparsity via a diffusive process over the network. The resulting algorithms endow networks with learning abilities and allow them to learn the sparse structure from the incoming data in real-time, and also to track variations in the sparsity of the model. We provide convergence and mean-square performance analysis of the proposed method and show under what conditions it outperforms the unregularized diffusion version. We also show how to adaptively select the regularization parameter. Simulation results illustrate the advantage of the proposed filters for sparse data recovery.
New Onset of Atrial Fibrillation in a Medical ICU: Prevalence and Risk Factors  [PDF]
S. Della Ayed, S. Ayed, R. Atig, N. Tilouche, H. Ben Sik Ali, R. Gharbi, M. Fekih Hassen, S. Elatrous
International Journal of Clinical Medicine (IJCM) , 2012, DOI: 10.4236/ijcm.2012.37105
Abstract: Objectives: To evaluate the prevalence and the risk factors of new onset atrial fibrillation (AF) in a single medical ICU. Methods: A prospective observational study was conducted in a 10 bed single medical ICU over a period of 18 months. All patients with sinus rhythm admitted in the medical ICU were included. Those presenting with any arrhythmia on admission, having a PACEMAKER or having undergone a recent cardiothoracic surgery were excluded. Results: Of the 377 patients included on the study, atrial fibrillation occurred in 26 patients (7%). Patients who developed AF were older, had higher severity scores on admission, and required significantly more fluids, catecholamine, and mechanical ventilation. They had a longer ICU and hospital LOS. ICU mortality was significantly higher in AF patients. Five inde- pendent risk factors of AF were identified by multivariate analysis: advanced age, the presence of COPD, sepsis, car- diogenic shock, and hypoxemia. Conclusion: AF occurs in approximately 7% of medical critically ill patients and is associated with age, a history of COPD, the presence of sepsis, cardiogenic shock and hypoxemia. AF occurs in more critically ill patients and is associated with increased morbidity and mortality.
Melorheostosis associated with peripheral form spondyloarthropathy: new image with 18-fluoride positron emission tomoscintigraphy coupled to computed tomography
Hassani H,Slama J,Hayem G,Ben Ali K
Open Access Rheumatology: Research and Reviews , 2012,
Abstract: Hakim Hassani1–3, Jér me Slama1,3, Gilles Hayem4, Khadija Ben Ali1, Laure Sarda-Mantel1,3, Samuel Burg1,3, Dominique Le Guludec1,31Department of Nuclear Medicine, H pital Bichat, Paris, France; 2Radiology, H pital Robert Debré, Paris, France; 3University Paris VII Denis Diderot, Paris, France; 4Rheumatology, H pital Bichat, Paris, FranceAbstract: Melorheostosis is a rare benign bone pathology which can be responsible for incapacitating pain and bone deformations. Its imaging abnormalities are often typical. We describe here the case of a patient with melorheostosis involving the lower limbs, associated with a peripheral form of inflammatory spondyloarthropathy, who underwent 18FNa positron emission tomography coupled to a computed tomography scan. Our objective is to present this new image, to show the value of this new modality and emphasize its advantages compared to the 99mTechnetium bone scan.Keywords: melorheostosis, PET-CT, 18FNa, bone scan, 18F-fluoride
Macronutrients Effect on Secondary Somatic Embryogenesis of Moroccan Cork Oak (Quercus suber L.)  [PDF]
Naouar Ben Ali, Ahmed Lamarti
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.513199
Abstract:

To define the preliminary embryogenesis culture conditions of Moroccan Cork Oak (Quercus suber L.) in secondary propagation systems, secondary embryos formation from primary embryos were analyzed using seven macronutrient medias: (Chalupa) (BTM), Murashige and Skoog (MS), Schenk and Hildebrant (SH), Schenk and Hildebrant with half content macronutrients (SH ?), full Gamborg (G), Margara (N30K) and Woody Plant Media(WPM). Mature primary embryos at cotyledonal stage of 8 - 10 mm, were placed in each culture medium, and supplemented with 30 g/l of glucose and 7 g/l of agar without PGR. The experimental design consisted of a Petri dish containing three embryos explants. Each one of the seven treatments was composed of ten Petri dishes. Mean number of secondary somatic embryos, clusters and new embryogenic formation on clusters were recorded after 8 weeks, and evaluated by statistical analysis. There were no significant differences (p ≤ 0.05) in clusters and new embryos on clusters formation among evaluated media; but mean number of secondary embryos was significantly higher in N30K (4.37 ± 0.48) compared with control media (1.37 ± 0.15). The morphology of secondary embryos grown in the N30K medium exclusively showed the presence of three embryogenic stages: early cotyledonal with translucide aspect, white opaque, or green, and mature embryos. These results indicate that the medium do influence the morphogenic characteristics of produced embryos. Our finding revealed that secondary somatic embryos produced in N30K medium presented better

Predictive Factors of Surgery in Peptic Stenosis of the Bulb  [PDF]
Mohamed Ben Mabrouk, Aida Ben Slama Trabelsi, Mehdi Ksiaa, Waad Farhat, Ali Jmaa, Ali Ben Ali
Open Journal of Gastroenterology (OJGas) , 2015, DOI: 10.4236/ojgas.2015.59021
Abstract: The bulb ulcer stenosis, becoming exceptional in developed countries, remains frequent in our country despite the use of the antisecretory. The purpose of our study was to study epidemiological, diagnostic, and evolutionary complication particularities, and to find potential predictive factors of resistance of ulcer stenosis of the bulb to the pump inhibitors Proton through a recent series. This is a retrospective and descriptive study involving 105 patients, treated for ulcer stenosis of the bulb between January 2007 and December 2012. All our patients had received inhibitors of Proton pump, parenterally for 7 days. They were divided into 2 groups according to their response to treatment: the first group (G1) was sensitive and the second (G2) was resistant. All patients of the G2 were operated. We had compared the two groups. There was no statistically significant difference concerning age, sex, blood group and smoking between the two groups. In univariate study, the age of the epigastralgies was greater than or equal to 9 years; the clapotage fasting, dilation and gastric atony, objectified by the oesogastroduodenal transit were significantly associated with the failure of medical treatment. Only gastric atony and seniority of the disease over 9 years were independent risk factors of resistance to the Proton pump inhibitors in multivariate study.
Chemopreventive effect of cactus Opuntia ficus indica on oxidative stress and genotoxicity of aflatoxin B1
Dalel Brahmi, Chayma Bouaziz, Yousra Ayed, Hédi Ben Mansour, Lazhar Zourgui, Hassen Bacha
Nutrition & Metabolism , 2011, DOI: 10.1186/1743-7075-8-73
Abstract: Adult, healthy balbC (20-25 g) male mice were pre-treated by intraperitonial administration of CCE (50 mg/Kg.b.w) for 2 weeks. Control animals were treated 3 days a week for 4 weeks by intraperitonial administration of 250 μg/Kg.b.w AFB1. Animals treated by AFB1 and CCE were divided into two groups: the first group was administrated CCE 2 hours before each treatment with AFB1 3 days a week for 4 weeks. The second group was administrated without pre-treatment with CCE but this extract was administrated 24 hours after each treatment with AFB1 3 days a week for 4 weeks.Our results clearly showed that AFB1 induced significant alterations in oxidative stress markers. In addition, it has a genotoxic potential and it increased the expression of pro apoptotic proteins p53 and bax and decreased the expression of bcl2. The treatment of CCE before or after treatment with AFB1, showed (i) a total reduction of AFB1 induced oxidative damage markers, (ii) an anti-genotoxic effect resulting in an efficient prevention of chromosomal aberrations and DNA fragmentation compared to the group treated with AFB1 alone (iii) restriction of the effect of AFB1 by differential modulation of the expression of p53 which decreased as well as its associated genes such as bax and bcl2.We concluded that CCE might have a hepatoprotective effect against aflatoxicosis in mice, probably acting by promoting the antioxidant defence systems.Primary liver cancer, also known as hepatocellular carcinoma (HCC), happens to be the sixth most common cancer as well as the third leading cause of cancer mortality in the world [1]. The incidence of HCC is on the rise in multiple geographic areas, including Asia Pacific, sub-Saharan Africa, Southern Europe as well as North America. It has been estimated that there will be more than 22,000 new cases and about 18,000 deaths in the United States in 2009 due to liver cancer which represents about 4% of cancer mortality in this country [2]. The vast majority of HCC cases a
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