Simulation and management of on-demand irrigation systems: a combined agrohydrological and remote sensing approach

Rational use of water resources in agriculture requires improvements in the efficiency of irrigation. Many irrigation systems, particularly in Mediterranean regions, have been enhanced by replacing open channel conveyance systems with pressurised pipelines. This allows to provide water on-demand. Increased demand of water for civil and industrial uses and a progressive reduction of available water resources compel a more efficient use of irrigation water. To achieve this goal irrigation managers need to understand and to monitor the processes which determine the operation of an irrigation system.In this thesis a procedure integrating the agrohydrological aspects of irrigation with hydraulic and management aspects has been developed. The procedure named SIMODIS (SImulation and Management of On-Demand Irrigation Systems) is based on the integration of different tools such as agrohydrological and hydraulic simulation models, remote sensing and GIS techniques.An irrigation system is described as a set of elementary (e.g. individual fields) connected by the pressurised conveyance system. The spatial distribution of soil water deficit in each elementary unit is computed daily by combining the soil water model SWAP with occasional satellite-based estimates of crop water requirements. A methodology has been developed to obtain spatially distributed input data for the soil water model SWAP i.e. the soil hydraulic properties and the upper and lower boundary conditions.Multispectral satellite images are used to map the crop coefficients needed for the definition of the SWAP upper boundary condition in each elementary unit of the irrigation district. Two different approaches have been proposed. The first is based on classification techniques, where clustering algorithms are applied to derive the spectral classes corresponding to different crop coefficient values. In the second approach, the crop coefficient is analytically related to the canopy variables determining the potential evapotranspiration i.e. leaf area index, surface albedo and crop height. At-surface directional spectral reflectance are used to estimate these canopy variables from which the value of crop coefficient is calculated.The spatial distribution of farmers' water demand is derived on a daily basis from the soil water deficit according to predefined irrigation scheduling criteria. Before applying this farmers' water demand distribution for the given day, the SIMODIS procedure assess whether water demand is consistent with the available amount of water resources and with the structural and operational constraints imposed by the conveyance and distribution system. For this purpose a steady-state simulation model of pipeline hydraulics is used in SIMODIS. The final distribution of farmers' water demand is then resulting from a three-tiered adaptation of irrigation schedule considering: i) the limitation of flow rate at delivery outlets, ii) the limitation of available water resources, iii) the required minimum hydraulic head at the delivery outlets.The procedure SIMODIS has been applied in the Gromola irrigation district of approximately 3000 ha in southern Italy. Measurements of irrigation volumes were used to identify the parameters driving irrigation scheduling. Irrigation efficiency indicators were calculated from the spatial distribution of actual transpiration rates and of the corresponding irrigation volumes applied. To illustrate the use of SIMODIS in support of irrigation decision making, alternative scenarios of water management were simulated and compared.The development of SIMODIS demonstrated that agrohydrological simulation models and remote sensing can be effectively combined to describe the operation of an irrigation system. These techniques have reached a sufficient degree of reliability to be transferred to practical applications. The estimation of crop coefficients by means of remote sensing techniques is of general usefulness in the definition of the upper boundary condition of distributed hydrological simulation models and it can be applied to evaluate with satisfactory accuracy the crop water requirements at regional scale. In the future new types of satellite sensors will probably allow for a more precise determination of the canopy variables, thus providing novel opportunities in the integration between agrohydrological simulation models and remote sensing techniques.</p

A genetic algorithm for the design of a fuzzy controller for active queue management

Active queue management (AQM) policies are those policies of router queue management that allow for the detection of network congestion, the notification of such occurrences to the hosts on the network borders, and the adoption of a suitable control policy. This paper proposes the adoption of a fuzzy proportional integral (FPI) controller as an active queue manager for Internet routers. The analytical design of the proposed FPI controller is carried out in analogy with a proportional integral (PI) controller, which recently has been proposed for AQM. A genetic algorithm is proposed for tuning of the FPI controller parameters with respect to optimal disturbance rejection. In the paper the FPI controller design metodology is described and the results of the comparison with random early detection (RED), tail drop, and PI controller are presented

The role of lactate besides the lactic acidosis

Lactic acidosis (LA) is the most common form of metabolic acidosis defined by values of lactate greater than 5 mmol / l and by a pH <7.34. The pathogenesis of LA involves hypoxic (type A) and non hypoxic (type B) causes which are often coexisting. Lactic acidosis is usual in hospitalized population especially in subjects in intensive care units, in which lactate levels on admission could be predictors of mortality even in the absence of organ dysfunction or shock. The outcome is mainly dependent on the cardiovascular effects of acidosis. In subjects with cardiogenic shock, the increased lactate/pyruvate ratio, detectable at onset, is correladed with mortality. An early assessment of blood and tissue lactate levels could play a role in the therapeutic management as well as in outcome. LA could be a unfavorable prognostic factor in cancer. The lactate would act also as "signal molecule" and as a promoting factor in angiogenesis and tumor progression. In the presence of risk factors for LA the role of metformin may be overrated. Despite the doctrinal progress to understand the pathogenesis and pathophysiology, there is not univocal consensus on the therapeutic treatment of LA. The identification and the attempt to remove the cause of acidosis are main aims; treatment with sodium bicarbonate is a matter of debate as the data on the cardiovascular effects and mortality are unclear. The therapy with carbicarb, dichloroacetate or THAM has shown no specific advantages in terms of mortality. In experimental models of LA and shock the use of sodium-hydrogen exchanger-1 (NHE1) selective inhibitors reduces cell damage and inflammatory cytokines synthesis; it also improves cardiac performance and decreases mortality

Mechanical rotational thrombectomy in long femoropopliteal artery and stent occlusion in COVID-19 patient: Case report

Introduction: Coronavirus disease-19 (COVID-19) has been increasingly associated with thromboembolic complications. COVID-19 infection has a thrombogenic potential for stents. Herein, we report a case of stent thrombosis in diabetic obese patient COVID-19 positive where was previously released a Multilayer Flow Modulator stent (MFM) for large popliteal aneurysm. Case report: A 78-year-old male was referred to our hospital for fever and acute pain in the left leg. At history, the same patient had endovascular procedure for a large symptomatic popliteal aneurysm, treated through release of three MFM. The pulmonary CT scan showed COVID-19 infection with confirm of rhino-laryngeal swab. Duplex ultrasound and CT-angiography showed complete thrombosis of stents. The treatment consisted of mechanical thrombectomy using an 8Fr catheter Rotarex plus release of Vibahn stent-graft. Discussion: COVID-19 patients can present arterial occlusion. In literature are not reported cases about thrombosis peripheral stent. Minimally invasive approaches in redo-procedure reduce risk of infection. Rotarex device was used in revascularization of acute and subacute iliac and femoropopliteal arteries. The goal is to have a debulking, to avoid an incomplete deployment of stent-graft. In our precedent experience, MFM and stent-graft to treatment of popliteal aneurism were safe. It is important to monitor these patients for early identification of failure and rapprochement. In this case, the COVID-19 infection was determinant in promoting thrombosis. Conclusions: COVID-19 increases risk of thrombosis stent. In our experience debulking through Rotarex and stenting, were decisive factors for revascularization and limb salvage

Lipid peroxidation and nitric oxide metabolites in a group of subjects with obstructive sleep apnea syndrome

It is known that in OSAS the plasma lipid peroxidation has an opposite behavior in comparison with nitric oxide metabolites. In the re-examination of our survey of OSAS infjects we calculated the ratio between thiobarbituric acid reactive infstances (TBARS) and nitric oxide metabolites (NOx) in relation to OSAS severity. The study has regarded 48 OSAS infjects infdivided in two infgroups according to the apnea/hypopnea index-AHI-(Low=21 infjects with AHI 30). From the obtained data it is evident that the TBARS/NOx ratio is significantly higher in the H infgroup compared to L infgroup as well as this ratio is reduced in L infgroup in comparison with the whole group of OSAS infjects. In the entire group of OSAS infjects the TBARS/NOx ratio results positively correlated with AHI and ODI and inversely correlated with mSO2

Analysis of the Blood Viscosity Behavior in the Sicilian Study on Juvenile Myocardial Infarction

Considering the role of hemorheology in coronary circulation, we studied blood viscosity in patients with juvenile myocardial infarction. We examined whole blood viscosity at high shear rate using the cone-on-plate viscosimeter Wells-Brookfield \ubd LVT and at low shear rate employing a viscometer Contraves LS30 in 120 patients (aged <46 years) with myocardial infarction, at the initial stage and subsequently 3 and 12 months after. At the initial stage, patients had an increased whole blood viscosity in comparison to normal controls. This hemorheological profile was not influenced by the cardiovascular risk factors, nor by the extent of coronary lesions, even if some differences were evident between patients with ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI). The blood viscosity pattern at the initial stage did not influence recurring ischemic events or the onset of heart failure during an 18 months\u2019 follow-up. The neutrophil to lymphocyte ratio did not affect the blood viscosity pattern. We reevaluated 83 patients 3 months after and 70 patients 12 months after the acute coronary syndrome, and we found that the hemorheological parameters were still altered in comparison to normal controls at both times. We observed an impairment of the hemorheological pattern in young patients with myocardial infarction, partially influenced by the infarction type (STEMI and NSTEMI) and persisting in the long term