761 research outputs found
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 coordinate deregulation of microRNAs expressed in mucosa adjacent to tumor predicts relapse after resection in localized colon cancer
Up to 20% of colorectal cancer (CRC) node-negative patients develop loco-regional or distant recurrences within 5 years from surgery. No predictive biomarker able to identify the node-negative subjects at high risk of relapse after curative treatment is presently available.Forty-eight localized (i.e. stage I-II) colon cancer patients who underwent radical tumor resection were considered. The expression of five miRNAs, involved in CRC progression, was investigated by qRT-PCR in both tumor tissue and matched normal colon mucosa.Interestingly, we found that the coordinate deregulation of four miRNAs (i.e. miR-18a, miR-21, miR-182 and miR-183), evaluated in the normal mucosa adjacent to tumor, is predictive of relapse within 55 months from curative surgery.Our results, if confirmed in independent studies, may help to identify high-risk patients who could benefit most from adjuvant therapy. Moreover, this work highlights the importance of extending the search for tissue biomarkers also to the tumor-adjacent mucosa
“Screwed from the start”: How women perceive opportunities and barriers for building a successful research career
After finishing the PhD, the researcher enters a stage in their early research career where more independence is expected. Within a relatively short time period, the researcher needs to gather research experience and support in the form of tangible resources as funding, and intangible resources like access to research networks, close collaborations, and mentorship to support their next career stage. How resources are allocated are therefore important determinants for the success of researchers. However, research shows that the resource allocation decisions in academia are biased in favor of men, with many of these gender biases that influence the success of research careers increasing. In this study, we asked women employed as early-career researchers (WECRs) about how they view their opportunities and potential for long-term success within academia, and how this relates to the resources that they have access to. We found that the WECRs were given few resources and support, and that they perceived that finding resources important for their career was up to themselves. The noticeable male dominance in who receives resources and positions within the university and the lack of women as role-models signals to WECRs that they are not wanted in academia. The WECRs suggest several ways to improve the possibilities for a successful research career for women on more equal terms as their male collegues: these include transparent processes for resource allocations, equal opportunity officers in all hiring processes, and mandatory gender training for all senior research and administrative staff. All the actions suggested are within the control of the university
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
genetic diversity and relationship among the three autochthonous sicilian donkey populations assessed by microsatellite markers
AbstractIn the developed countries donkey has lost its main function as draft animal because of the mechanization in agri-culture; as a consequence donkey population was greatly reduced. According to SAVE monitoring institute, three of the eight Italian endangered donkey breeds are native of Sicily (Ragusano, Pantesco, Grigio Siciliano). Urgent safeguard plans are required. The aim of this work is to investigate the distribution of genetic diversity and the relationships among the three Sicilian autochthonous donkey breeds using a set of microsatellite markers. A total of 116 blood samples (61 Ragusano, 39 Pantesco, 16 Grigio Siciliano) were collected in 9 herds all over Sicily. Representative samples of Ragusano and Grigio donkey populations consist of unrelated individuals, whereas the sample of Pantesco represents nearly the entire studbook-registered population managed by "Ispettorato Ripartimentale delle Foreste di Erice (TP)" in the "Azienda S. Matteo". Genomic DNA was amplified at 11 microsatellite..
Mitochondrial DNA control region variation in Sanfratellano horse and two other Sicilian autochthonous breeds
Mitochondrial D-loop hypervariable region was analysed in 20 Sanfratellano and two other Sicilian autochthonous horse breeds (20 Sicilian Oriental Purebred and 20 Sicilian Indigenous) in order to investigate matrilineal genetic diversity. A total of 20 different haplotypes were identified sequencing a fragment of 397 bp; overall, haplotypes showed 31 polymorphic sites (7.8%). High diversity was detected in Sanfratellano (11 haplotypes) and Sicilian Indigenous (13 haplotypes), whereas only one haplotype was found in Sicilian Oriental Purebred. Sanfratellano sequences were compared with those belonging to the other Sicilian autochthonous horses and 118 sequences selected from the GenBank database in order to calculate the statistics of molecular diversity. Six haplotypes were exclusive of Sanfratellano which shares haplotype C, D, H, and O with the Sicilian Indigenous and haplotype U with the Sicilian Oriental Purebred; not significant differentiation was found between Sanfratellano and Sicilian Indigenous. BLAST search showed Sicilian haplotypes overlap with the database sequences but for three. Phylogenetic analysis did not show monophyletic group for Sanfratellano samples or the other breeds included in this analysis
The layout of a GIS under development by the European Commission for headquarters and in-field decision support
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