34 research outputs found

    Germination and Seedling Growth of a Set of Rapeseed (Brassica napus) Varieties under Drought Stress Conditions

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    Drought stress is one of the major abiotic factors affecting seed germination and plant growth especially in arid and semi-arid regions. In this study, we investigated the effects of drought stress on seed germination and seedling growth of five varieties of rapeseed. Seven drought stress levels of zero (control), -3, -5, -7, -9, -11 and -13 bars were performed using polyethylene glycol-6000 (PEG-6000). A completely randomized design with three replications was used for this experiment. Germination percentage (GP), germination rate (GR), mean germination time (MGT), root length (RL) and shoot length (SL) were measured to evaluate the varieties response to PEG-induced drought stress. Drought stress, variety and the interaction drought × variety had a significant effect on all studied parameters. GP and GR decreased with the increase in stress level, while MGT increased. There were no seeds germinated for all varieties at -11 bars and -13 bars. Shoot length decreased with increasing drought stress but different varieties show different performance under stress environment. Root length decreased with increasing level of severe drought stress. However, the presence of moderate drought stress could even improve the root growth of the investigated varieties. The varieties ‘INRA-CZH2' and ‘INRA-CZH3' exhibited the highest germination percentage and the best early seedling growth. Thus, they could be recommended for environments with early cropping cycle drought

    Coupled experimental/numerical workflow for assessing quantitative diagenesis and dynamic porosity/permeability evolution in calcite-cemented sandstone reservoir rocks

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    Some of the world best hydrocarbon reservoirs (carbonates and siliciclastics) are also believed to be valuable for subsurface storage of CO2 and other fluids. Yet, these reservoirs are heterogeneous in terms of their mineralogy and flow properties, at varying spatial-temporal scales. Therefore, predicting the porosity and permeability (flow properties) evolution of carbonates and sandstones remains a tedious task. Diagenesis refers to the alteration of sedimentary rocks through geologic time, mainly due to rock-fluid interactions. It affects primarily the flow properties (porosity and permeability) of already heterogeneous reservoir rocks. In this project a new approach is proposed to calculate/quantify the influence of diagenetic phases (e.g. dissolution, cement plugging) on flow properties of typical sandstone reservoir rocks (Early Jurassic Luxembourg Formation). A series of laboratory experiments are performed in which diagenetic phases (e.g. pore blocking calcite cement in sandstone) are selectively leached from pre-studied samples, with the quantification of the petrophysical characteristics with and without cement to especially infer permeability evolution. Poorly and heavily calcite-cemented sandstone samples, as well as some intermediate cemented samples were used. The results show a distinctive dissolution pattern for different cementation grades and varying Representative Elementary Volumes (REVs). These conclusions have important consequences for upscaling diagenesis effects on reservoirs, and the interpretation of geochemical modelling results of diagenetic processes. The same approach can be applied on other type of cements and host-rocks, and could be improved by integrating other petrophysical analyses (e.g. petroacoustic, NMR)

    Coupled experimental/numerical workflow for assessing quantitative diagenesis and dynamic porosity/permeability evolution in calcite-cemented sandstone reservoir rocks

    No full text
    Some of the world best hydrocarbon reservoirs (carbonates and siliciclastics) are also believed to be valuable for subsurface storage of CO2 and other fluids. Yet, these reservoirs are heterogeneous in terms of their mineralogy and flow properties, at varying spatial-temporal scales. Therefore, predicting the porosity and permeability (flow properties) evolution of carbonates and sandstones remains a tedious task. Diagenesis refers to the alteration of sedimentary rocks through geologic time, mainly due to rock-fluid interactions. It affects primarily the flow properties (porosity and permeability) of already heterogeneous reservoir rocks. In this project a new approach is proposed to calculate/quantify the influence of diagenetic phases (e.g. dissolution, cement plugging) on flow properties of typical sandstone reservoir rocks (Early Jurassic Luxembourg Formation). A series of laboratory experiments are performed in which diagenetic phases (e.g. pore blocking calcite cement in sandstone) are selectively leached from pre-studied samples, with the quantification of the petrophysical characteristics with and without cement to especially infer permeability evolution. Poorly and heavily calcite-cemented sandstone samples, as well as some intermediate cemented samples were used. The results show a distinctive dissolution pattern for different cementation grades and varying Representative Elementary Volumes (REVs). These conclusions have important consequences for upscaling diagenesis effects on reservoirs, and the interpretation of geochemical modelling results of diagenetic processes. The same approach can be applied on other type of cements and host-rocks, and could be improved by integrating other petrophysical analyses (e.g. petroacoustic, NMR)

    Leiomyosarcoma of the lower rectum managed by radiotherapy and surgery: A case report and review of literature.

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    Rectal leiomyosarcoma is a very rare entity. Surgery is the main treatment, but the place of radiation therapy remains unclear. A 67-year-old woman was referred for a few-weeks' history of bleeding and anal pain intensified during defecation. Pelvic magnetic resonance imaging (MRI) showed a rectal lesion and biopsies revealed a leiomyosarcoma of the lower rectum. She was free of metastasis on computed tomography imaging. The patient refused radical surgery. After discussion by a multidisciplinary team, the patient received pre-operative long-course radiotherapy followed by surgery. The tumor was treated with 50Gy delivered in 25 fractions, within 5 weeks. The aim of radiotherapy was local control, allowing organ-preservation. Four weeks after radiation therapy, organ-preservation surgery could be performed. She had no adjuvant treatment. At 38-months follow-up, she had no local recurrence. However, distant recurrence (lung, liver, and bone) was detected 38 months after the resection and was managed by intra-venous doxorubicin 60mg/m <sup>2</sup> and dacarbazine 800mg/m <sup>2</sup> every 3 weeks. The patient was in a stable condition for nearly 8 months. The patient died 4 years and 3 months after the diagnosis

    Free-sodium salts mixture and AlgySalt® use as NaCl substitutes in fresh and cooked meat products intended for the hypertensive population

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    This work aims at reducing the use of added NaCl in processed meat products because of its negative effects on hypertensive population by replacing it by sodium-free salts mixture (SM: KCl, MgCl and CaCl) in fresh and cooked sausages. The technological, sensory, and microbiological effects of SM were compared with a commercial replacer based on seaweed extracts (AlgySalt®). A total substitution of NaCl with the latter and a partial one with SM (80% and 50%) were studied in cooked sausages and a total NaCl substitution with both substitutes was performed in fresh sausages. As a result, hardness increased in AlgySalt® reformulated samples, while it decreased when 80% SM were used. Whereas, AlgySalt® induced less cooking loses than SM. To some extent, microbiological counts showed a similarity between reformulated and control samples for both sausage types, whereas reformulated products containing SM revealed better sensory properties for both meat products. Therefore, using SM as NaCl replacer is adequate for processed meat products.The authors would like to thank the PASRI for Dr. Mehdi Triki's Postdoctoral scholarship and the Laboratory of Food Analysis, Valorization and Security (LAVASA) of the National School of Engineers of Sfax for its collaboration to realize the analytical part of this study.Peer Reviewe
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