Impact of direct seeding on soil water retention in semi-arid area (region highlands of western Algeria)

This investigation is falls within the framework of conservation agriculture. Indeed, twentyfive years after the first of zero tillage farming experiences, this new method was named crop conservation agriculture because it helps preserve soil nutrients, water absorption enhancing and infiltration and biodiversity by maintaining the natural equilibrium in the soil. The objective of this is study is to compare the impact of the tillage (conventional work and the direct sowing) on water properties of the soil, especially the water-holding capacity of the soil in semi-arid zone (case of Tiaret region). According to the results, the comparative analysis between the two types of tillage (direct drilling sowing and conventional tillage) shows that water parameters studied such as moisture equivalent (He), of holding capacity (Cr), wilting point (Pf) and AWR (UK) are higher in the useful reserve case of direct seeding than in the case of conventional labor.Keywords: Conservation agriculture, direct sowing, conventional labor, soil moisture, holding capacit

EFFETS DU TRAVAIL DU SOL SUR LE COMPORTEMENT PHYSIQUE ET BIOLOGIQUE D’UN SOL SOUS UNE CULTURE DE LENTILLE (LENS EXCULENTA) DANS LA RÉGION DE TIARET ALGÉRIE

Soil management practices influence soilphysical and chemicalcharacteristics and bring about changes in the soilmicrobialcommunity structure and function. In thisstudy, the effects of conventional and no-tillage practices on microbialcommunity structure, selectedphysicochemicalpropertiesweredetermined in a continuous corn system on a silt loamsoil. The no-tillage treatmentresulted in highersoilcarbon and nitrogen contents, viable microbialbiomass, at the 0– 25 cm depththan the conventional tillage treatment. Soilmicrobialcommunity structure assessed,using indicative of fungi, bacteria, in the no-till surface soil. Results of principal components analysisbased on soilphysicochemical in agreement. Theseresultsindicatethat tillage practice and soildepthweretwo important factorsaffectingsoilmicrobialcommunity structure and activity, and conservation tillage practices improvebothphysicochemical and microbiologicalproperties of soil

Improved control strategy of DFIG-based wind turbines using direct torque and direct power control techniques

This paper presents different control strategies for a variable-speed wind energy conversion system (WECS), based on a doubly fed induction generator. Direct Torque Control (DTC) with Space-Vector Modulation is used on the rotor side converter. This control method is known to reduce the fluctuations of the torque and flux at low speeds in contrast to the classical DTC, where the frequency of switching is uncontrollable. The reference for torque is obtained from the maximum power point tracking technique of the wind turbine. For the grid-side converter, a fuzzy direct power control is proposed for the control of the instantaneous active and reactive power. Simulation results of the WECS are presented to compare the performance of the proposed and classical control approaches.Peer reviewedFinal Accepted Versio

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

Background Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications. Methods We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC). Findings In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683–0·717]). Interpretation In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required. Funding British Journal of Surgery Society