915 resultados para Best-case scenario
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The topic of this thesis is the design and the implementation of mathematical models and control system algorithms for rotary-wing unmanned aerial vehicles to be used in cooperative scenarios. The use of rotorcrafts has many attractive advantages, since these vehicles have the capability to take-off and land vertically, to hover and to move backward and laterally. Rotary-wing aircraft missions require precise control characteristics due to their unstable and heavy coupling aspects. As a matter of fact, flight test is the most accurate way to evaluate flying qualities and to test control systems. However, it may be very expensive and/or not feasible in case of early stage design and prototyping. A good compromise is made by a preliminary assessment performed by means of simulations and a reduced flight testing campaign. Consequently, having an analytical framework represents an important stage for simulations and control algorithm design. In this work mathematical models for various helicopter configurations are implemented. Different flight control techniques for helicopters are presented with theoretical background and tested via simulations and experimental flight tests on a small-scale unmanned helicopter. The same platform is used also in a cooperative scenario with a rover. Control strategies, algorithms and their implementation to perform missions are presented for two main scenarios. One of the main contributions of this thesis is to propose a suitable control system made by a classical PID baseline controller augmented with L1 adaptive contribution. In addition a complete analytical framework and the study of the dynamics and the stability of a synch-rotor are provided. At last, the implementation of cooperative control strategies for two main scenarios that include a small-scale unmanned helicopter and a rover.
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This PhD thesis aimed to assess the status of common sole, one of the main commercial stocks in the Adriatic Sea, using a mix of conventional and innovative techniques to provide more reliable estimates of stock status compared to past advice. First, a meta-analysis was carried out using data-poor assessment model to analyze the whole catch assemblage of rapido fishery. The outcomes were used to estimate rebuilding time and forecast catches under different harvest control rule scenarios, with a reduction of 20% of fishing effort being suggested as a way to allow most of the species to recover to sustainable levels. Secondly, an ensemble of data-rich assessment models was developed to better incorporate uncertainty by using alternative hypotheses of main parameters. This was the first time an ensemble of models has been used in the Mediterranean to provide management advice. Consistent with data-poor analysis results, the ensemble outcomes indicated that the common sole stock was showing a recovering trend probably due to the effective management actions underway in the area rather than the moderate effort reduction according to the actual management plan. Moreover, back-calculation measurements were used to fit and compare monophasic and biphasic growth curves through the use of non-linear mixed effects models. The analyses revealed that the fitting of the biphasic curve was superior, confirming the theory that growth in size would decrease as a consequence of reproductive effort. A stock assessment simulation showed how the use of the monophasic pattern would result in a critical overestimation of biomass that could lead to a greater risk of overfishing. As a final step, a simulation-testing procedure was applied to determine the best performing reference points using stock-specific characteristic. The procedure could be routinely adopted to increase transparency in reference points calculation enhancing the credibility of scientific advice.
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Coastal ecosystems represent an inestimable source of biodiversity, being among the most productive areas on the planet. Despite the great ecological and economic value of those environments, many threats endanger the species living in this ecosystem, like the rapid warming and the sea acidification, among many other. Benthic calcifying organisms (e.g. mollusks, corals and echinoderms) in particular, are among the most exposed to those hazards. These organisms use calcium carbonate as a structural and protective material through the biomineralization process, biologically controlled by the organism, but nevertheless, strongly influenced by the environmental surroundings. Evaluating how a changing environment can influence the process of biomineralization is critical to understand how those species of great ecological and economic importance will face the ongoing climate change. This thesis investigates the mechanism of biomineralization in different mollusks’ species of the Adriatic Sea, providing detailed descriptions of shells skeletal, biometric and growth parameters. Applying a multidisciplinary and multi-scale research approach, the influence of external environmental factors on the process of shell formation has been investigated. To achieve this purpose analysis were conducted both on current populations and on fossil remain, which allows to investigate ecological responses to past climate transitions. Mollusks’ shells in fact are one of the best tools to understand climate change in the past, present and future, since they record the environmental conditions prevailed during their life, reflected on the geochemical properties, microstructure and growth of the shell. This approach allowed to overcome the time scale limit imposed by field and laboratory survey, and better understand species long term adaptive response to changing environment, a crucial issue to define proper conservation and management strategies. Furthermore, the investigation of fossil record of mollusks assemblages offered the opportunity to evaluate the long-term biotic response to anthropogenic stressors in the north Adriatic Sea.
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Desmoid tumor (DT) is a common manifestation of Gardner's Syndrome (GS), although it is a rare condition in the general population. DT in patients with GS is usually located in the abdominal wall and/or intra-abdominal cavity. We report a case of a 32 years-old female patient with familial adenomatous polyposis (FAP), who was already submitted to total colectomy and developed multiple DT, located in the abdominal wall and in the left breast. The patient underwent several surgical procedures, with a multidisciplinary team of surgeons. Wide surgical resections of the left breast and the abdominal wall tumors were performed in separate steps. Polypropylene mesh reconstruction and muscle flaps were needed to cover the defects of the thoracic and abdominal walls. After partial necrosis of the adipose-cutaneous flap in the abdomen that required a new skin graft, she had a satisfactory outcome with complete healing of the surgical incisions. DT is frequent in GS, however, breast localization is very rare, with few cases reported in the literature. Recurrence of DT is not negligible, even after a wide surgical resection. GS patients must be followed up closely, and clinical examination, associated with imaging studies, should be performed to detect any signs of tumor. DT represents one of the most significant causes of the morbidity and mortality that affects FAP patients following colectomy. In general, the surgical procedures to excise DT are highly complex, requiring a multidisciplinary team.
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The Ophira Mini Sling System involves anchoring a midurethral, low-tension tape to the obturator internus muscles bilaterally at the level of the tendinous arc. Success rates in different subsets of patients are still to be defined. This work aims to identify which factors influence the 2-year outcomes of this treatment. Analysis was based on data from a multicenter study. Endpoints for analysis included objective measurements: 1-h pad-weight (PWT), and cough stress test (CST), and questionnaires: International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) and Urinary Distress Inventory (UDI)-6. A logistic regression analysis evaluated possible risk factors for failure. In all, 124 female patients with stress urinary incontinence (SUI) underwent treatment with the Ophira procedure. All patients completed 1 year of follow-up, and 95 complied with the 2-year evaluation. Longitudinal analysis showed no significant differences between results at 1 and 2 years. The 2-year overall objective results were 81 (85.3%) patients dry, six (6.3%) improved, and eight (8.4%) incontinent. A multivariate analysis revealed that previous anti-incontinence surgery was the only factor that significantly influenced surgical outcomes. Two years after treatment, women with previous failed surgeries had an odds ratio (OR) for treatment failure (based on PWT) of 4.0 [95% confidence interval (CI) 1.02-15.57). The Ophira procedure is an effective option for SUI treatment, with durable good results. Previous surgeries were identified as the only significant risk factor, though previously operated patients showed an acceptable success rate.
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This study focused on the method known as lean production as a work-related psychosocial risk factor in a Brazilian multinational auto parts company after its merger with other multinational companies. The authors conducted a qualitative analysis of two time points: the first using on-site observation and key interviews with managers and workers during implementation of lean production in 1996; the second, 16 years later, comparing data from a document search in labor inspection records from the Ministry of Labor and Employment and legal proceedings initiated by the Office of the Public Prosecutor for Labor Affairs. The merger led to layoffs, replacements, and an increase in the workday. A class action suit was filed on grounds of aggravated working conditions. The new production model led to psychosocial risks that increased the need for workers' health precautions when changes in the production process introduced new and increased risks of physical and mental illnesses.
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A retrospective case-control study based on craniometrical evaluation was performed to evaluate the incidence of basilar invagination (BI). Patients with symptomatic tonsillar herniation treated surgically had craniometrical parameters evaluated based on CT scan reconstructions before surgery. BI was diagnosed when the tip of the odontoid trespassed the Chamberlain's line in three different thresholds found in the literature: 2, 5 or 6.6 mm. In the surgical group (SU), the mean distance of the tip of the odontoid process above the Chamberlain's line was 12 mm versus 1.2 mm in the control (CO) group (p<0.0001). The number of patients with BI according to the threshold used (2, 5 or 6.6 mm) in the SU group was respectively 19 (95%), 16 (80%) and 15 (75%) and in the CO group it was 15 (37%), 4 (10%) and 2 (5%).
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This work assessed the environmental impacts of the production and use of 1 MJ of hydrous ethanol (E100) in Brazil in prospective scenarios (2020-2030), considering the deployment of technologies currently under development and better agricultural practices. The life cycle assessment technique was employed using the CML method for the life cycle impact assessment and the Monte Carlo method for the uncertainty analysis. Abiotic depletion, global warming, human toxicity, ecotoxicity, photochemical oxidation, acidification, and eutrophication were the environmental impacts categories analyzed. Results indicate that the proposed improvements (especially no-til farming-scenarios s2 and s4) would lead to environmental benefits in prospective scenarios compared to the current ethanol production (scenario s0). Combined first and second generation ethanol production (scenarios s3 and s4) would require less agricultural land but would not perform better than the projected first generation ethanol, although the uncertainties are relatively high. The best use of 1 ha of sugar cane was also assessed, considering the displacement of the conventional products by ethanol and electricity. No-til practices combined with the production of first generation ethanol and electricity (scenario s2) would lead to the largest mitigation effects for global warming and abiotic depletion. For the remaining categories, emissions would not be mitigated with the utilization of the sugar cane products. However, this conclusion is sensitive to the displaced electricity sources.
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Thoracic injuries in general are of great importance due to their high incidence and high mortality. Thoracic impalement injuries are rare but severe due to the combination of cause, effect and result. This study's primary objective is to report the case of a young man who was impaled by a two-wheeled horse carriage shaft while crashing his motorcycle in a rural zone. An EMT-B ferry was called at the crash scene and a conscious patient was found, sustaining a severe impalement injury to the left hemithorax, suspended over the floor by the axial skeleton with the carriage shaft coming across his left chest. As a secondary objective, a literature review of thoracic impalement injuries is performed. Cases of thoracic impalement injury require unique and individualized care based on injury severity and affected organs. Reported protocols for managing impalement injuries are entirely anecdotal, with no uniformity on impaled patient's approach and management. In penetrating trauma, it is essential not to remove the impaled object, so that possible vascular lesions remain buffered by the object, avoiding major bleeding and exsanguination haemorrhage. Severed impaled thoracic patients should be transferred to a specialist centre for trauma care, as these lesions typically require complex multidisciplinary treatment. High-energy thoracic impalement injuries are rare and hold a high mortality rate, due to the complexity of trauma and associated injuries such as thoracic wall and lung lesions. Modern medicine still seems limited in cases of such seriousness, not always with satisfactory results.
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The basic reproduction number is a key parameter in mathematical modelling of transmissible diseases. From the stability analysis of the disease free equilibrium, by applying Routh-Hurwitz criteria, a threshold is obtained, which is called the basic reproduction number. However, the application of spectral radius theory on the next generation matrix provides a different expression for the basic reproduction number, that is, the square root of the previously found formula. If the spectral radius of the next generation matrix is defined as the geometric mean of partial reproduction numbers, however the product of these partial numbers is the basic reproduction number, then both methods provide the same expression. In order to show this statement, dengue transmission modelling incorporating or not the transovarian transmission is considered as a case study. Also tuberculosis transmission and sexually transmitted infection modellings are taken as further examples.
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Palpable mass is a common complaint presented to the breast surgeon. It is very uncommon for patients to report breast mass associated with palpable masses in other superficial structures. When these masses are related to systemic granulomatous diseases, the diagnosis and initiation of specific therapy can be challenging. The purpose of this paper is to report a case initially assessed by the breast surgeon and ultimately diagnosed as granulomatous variant of T-cell lymphoma, and discuss the main systemic granulomatous diseases associated with palpable masses involving the breast.
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Pituitary macroadenomas are rare intracranial tumors. In a few cases, they may present aggressive behavior and invade the sphenoid sinus and nasal cavity, causing unusual symptoms. In this paper, we report an atypical case of pituitary adenoma presenting as a nasal mass. The patient was a 44-year-old woman who had had amenorrhea and galactorrhea for ten months, with associated nasal obstruction, macroglossia and acromegaly. Both growth hormone and prolactin levels were increased. Magnetic resonance imaging showed a large mass originating from the lower surface of the pituitary gland, associated with sella turcica erosion and tumor extension through the sphenoid sinus and nasal cavity. Histopathological analysis demonstrated a chromophobe pituitary adenoma with densely packed rounded epithelial cells, with some atypias and rare mitotic figures. There was no evidence of metastases. Macroadenoma invading the nasal cavity is a rare condition and few similar cases have been reported in the literature. This study contributes towards showing that tumor extension to the sphenoid sinus and nasopharynx needs to be considered and investigated in order to make an early diagnosis when atypical symptoms like nasal obstruction are present.
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A 46-year-old woman complained of blurred and distorted vision in both eyes. Ophthalmic examination showed that visual acuity was 20/200 for the right eye and counting fingers left eye. Fundoscopy revealed perimacular hemorrhages, aneurismal dilatation of the vessels in the posterior pole, and a white and elevated lesion adjacent to vascular changes. We report a case of idiopathic macular telangiectasia and epiretinal membrane that occurs concomitantly. To our knowledge, this is the first report that describes an association between idiopathic macular telangiectasia and epiretinal membrane formation.