49 research outputs found
Tecniche innovative per l'individuazione automatica degli oggetti sulle immagini satellitari
Implementazione di tecniche innovative quali la morfologia matematica, la template matching, i momenti invarianti e le reti neurali, nell'individuazione degli oggetti presenti nelle immagini satellitari a media, alta e altissima risoluzione spaziale
CubeSat constellations for disaster management in remote areas
In recent years, CubeSats have considerably extended their range of possible applications, from a low cost means to train students and young researchers in space related activities up to possible complementary solutions to larger missions. Increasingly popular, whereas CubeSats are still not a solution for all types of missions, they offer the possibility of performing ambitious scientific experiments. Especially worth considering is the possibility of performing Distributed Space Missions, in which CubeSat systems can be used to increase observation sampling rates and resolutions, as well as to perform tasks that a single satellite is unable to handle. The cost of access to space for traditional Earth Observation (EO) missions is still quite high. Efficient architecture design would allow reducing mission costs by employing CubeSat systems, while maintaining a level of performance that, for some applications, could be close to that provided by larger platforms, and decreasing the time needed to design and deploy a fully functional constellation. For these reasons many countries, including developing nations, agencies and organizations are looking to CubeSat platforms to access space cheaply with, potentially, tens of remote sensing satellites. During disaster management, real-time, fast and continuous information broadcast is a fundamental requirement. In this sense, a constellation of small satellites can considerably decrease the revisit time (defined as the time elapsed between two consecutive observations of the same point on Earth by a satellite) over remote areas, by increasing the number of spacecraft properly distributed in orbit. This allows collecting as much data as possible for the use by Disaster Management Centers. This paper describes the characteristics of a constellation of CubeSats built to enable access over the most remote regions of Brazil, supporting an integrated system for mitigating environmental disasters in an attempt to prevent the catastrophic effects of natural events such as heavy rains that cause flooding. In particular, the paper defines the number of CubeSats and the orbital planes required to minimize the revisit time, depending on the application that is the mission objective. Each CubeSat is equipped with the suitable payloads and possesses the autonomy and pointing capabilities needed to meet the mission requirements. Thanks to the orbital features of the constellation, this service could be exploited by other tropical countries. Coverage of other areas of the Earth might be provided by adjusting the number and in-orbit distribution of the spacecraft
Qualitative analysis of deforestation in the Amazonian Rainforest from SAR, optical and thermal sensors
A mitigação de mudanças climáticas e preservação de ecossistemas depende da redução do desmatamento e degradação de florestas tropicais. O objetivo deste estudo foi analisar imagens de radar, ópticas e termais para identificar
desmatamentos por corte raso no período de 2016 a 2018 em uma área localizada no arco de desmatamento da Amazônia. Foram utilizadas imagens de radar em bandas X (satélite COSMO-SkyMed) e C (satélite SENTINEL-1A), índices
de vegetação por diferença normalizada (NDVI), índices de umidade por diferença normalizada (NDMI) e temperaturas da superfície terrestre (LST) (satélite Landsat-8). As áreas com evidências de antropismo mapeadas com base nas
imagens do satélite COSMO-SkyMed no município de Novo Progresso (PA), período de 2016 a 2018, foram utilizadas
como máscara inicial. Imagens de radar identificaram, com boa precisão relativa, as épocas e as áreas de desmatamento.
NDVI e NDMI evidenciaram, respectivamente, quedas nas atividades fotossintéticas e nos níveis de biomassa nas áreas
de desmatamento identificadas. Já a LST foi mais elevada nas áreas de rebrota em relação à vegetação densa. A análise
do potencial de imagens de radar, ópticos e termais mostrou elevada relevância na detecção de desmatamento por corte
raso em ambiente florestal úmido.The mitigation of climate change and the preservation of ecosystems depends on the reduction of deforestation
and degradation of tropical forests. The objective of this study is to analyze radar, optical, and thermal images to identify
clear cut deforestation from 2016 to 2018 in an area located in the arch of deforestation of the Amazon forest. We used X-
(COSMO-SkyMed satellite) and C-bands (SENTINEL-1A satellite) radar data, normalized difference vegetation index
(NDVI), normalized difference moisture index (NDMI), and land surface temperature (LST) (Landsat-8 satellite). We
considered, as an initial mask, the areas with evidence of anthropogenic actions in the municipality of Novo Progresso
(PA), from 2016 to 2018. Radar features were able to be identified, with relative accuracy, the time and the area of deforestation. NDVI and NDMI indices showed, respectively, decrease in the photosynthetic activities and the biomass levels
in deforested areas. On the other hand, the LST was higher in regrowth areas than in dense vegetation. The analysis of
potential of radar, optical, and thermal data showed to be relevant in the identification of clear cut deforestation in tropical rainforest environment
Análise Qualitativa do Desmatamento na Floresta Amazônica a partir de Sensores SAR, Óptico e Termal
A mitigação de mudanças climáticas e preservação de ecossistemas depende da redução do desmatamento e degradação de florestas tropicais. O objetivo deste estudo foi analisar imagens de radar, ópticas e termais para identificar desmatamentos por corte raso no período de 2016 a 2018 em uma área localizada no arco de desmatamento da Amazônia. Foram utilizadas imagens de radar em bandas X (satélite COSMO-SkyMed) e C (satélite SENTINEL-1A), índices de vegetação por diferença normalizada (NDVI), índices de umidade por diferença normalizada (NDMI) e temperaturas da superfície terrestre (LST) (satélite Landsat-8). As áreas com evidências de antropismo mapeadas com base nas imagens do satélite COSMO-SkyMed no município de Novo Progresso (PA), período de 2016 a 2018, foram utilizadas como máscara inicial. Imagens de radar identificaram, com boa precisão relativa, as épocas e as áreas de desmatamento. NDVI e NDMI evidenciaram, respectivamente, quedas nas atividades fotossintéticas e nos níveis de biomassa nas áreas de desmatamento identificadas. Já a LST foi mais elevada nas áreas de rebrota em relação à vegetação densa. A análise do potencial de imagens de radar, ópticos e termais mostrou elevada relevância na detecção de desmatamento por corte raso em ambiente florestal úmido
Análise Qualitativa do Desmatamento na Floresta Amazônica a partir de Sensores SAR, Óptico e Termal
A mitigação de mudanças climáticas e preservação de ecossistemas depende da redução do desmatamento e degradação de florestas tropicais. O objetivo deste estudo foi analisar imagens de radar, ópticas e termais para identificar
desmatamentos por corte raso no período de 2016 a 2018 em uma área localizada no arco de desmatamento da Amazônia. Foram utilizadas imagens de radar em bandas X (satélite COSMO-SkyMed) e C (satélite SENTINEL-1A), índices
de vegetação por diferença normalizada (NDVI), índices de umidade por diferença normalizada (NDMI) e temperaturas da superfície terrestre (LST) (satélite Landsat-8). As áreas com evidências de antropismo mapeadas com base nas
imagens do satélite COSMO-SkyMed no município de Novo Progresso (PA), período de 2016 a 2018, foram utilizadas
como máscara inicial. Imagens de radar identificaram, com boa precisão relativa, as épocas e as áreas de desmatamento.
NDVI e NDMI evidenciaram, respectivamente, quedas nas atividades fotossintéticas e nos níveis de biomassa nas áreas
de desmatamento identificadas. Já a LST foi mais elevada nas áreas de rebrota em relação à vegetação densa. A análise
do potencial de imagens de radar, ópticos e termais mostrou elevada relevância na detecção de desmatamento por corte
raso em ambiente florestal úmid
Smallsat high-energy missions using ablative pulsed plasma thrusters
Faculdade UnB Gama (FGA
Lopinavir/Ritonavir and Darunavir/Cobicistat in Hospitalized COVID-19 Patients: Findings From the Multicenter Italian CORIST Study
Background: Protease inhibitors have been considered as possible therapeutic agents for COVID-19 patients. Objectives: To describe the association between lopinavir/ritonavir (LPV/r) or darunavir/cobicistat (DRV/c) use and in-hospital mortality in COVID-19 patients. Study Design: Multicenter observational study of COVID-19 patients admitted in 33 Italian hospitals. Medications, preexisting conditions, clinical measures, and outcomes were extracted from medical records. Patients were retrospectively divided in three groups, according to use of LPV/r, DRV/c or none of them. Primary outcome in a time-to event analysis was death. We used Cox proportional-hazards models with inverse probability of treatment weighting by multinomial propensity scores. Results: Out of 3,451 patients, 33.3% LPV/r and 13.9% received DRV/c. Patients receiving LPV/r or DRV/c were more likely younger, men, had higher C-reactive protein levels while less likely had hypertension, cardiovascular, pulmonary or kidney disease. After adjustment for propensity scores, LPV/r use was not associated with mortality (HR = 0.94, 95% CI 0.78 to 1.13), whereas treatment with DRV/c was associated with a higher death risk (HR = 1.89, 1.53 to 2.34, E-value = 2.43). This increased risk was more marked in women, in elderly, in patients with higher severity of COVID-19 and in patients receiving other COVID-19 drugs. Conclusions: In a large cohort of Italian patients hospitalized for COVID-19 in a real-life setting, the use of LPV/r treatment did not change death rate, while DRV/c was associated with increased mortality. Within the limits of an observational study, these data do not support the use of LPV/r or DRV/c in COVID-19 patients
Rationale and design of an independent randomised controlled trial evaluating the effectiveness of aripiprazole or haloperidol in combination with clozapine for treatment-resistant schizophrenia
<p>Abstract</p> <p>Background</p> <p>One third to two thirds of people with schizophrenia have persistent psychotic symptoms despite clozapine treatment. Under real-world circumstances, the need to provide effective therapeutic interventions to patients who do not have an optimal response to clozapine has been cited as the most common reason for simultaneously prescribing a second antipsychotic drug in combination treatment strategies. In a clinical area where the pressing need of providing therapeutic answers has progressively increased the occurrence of antipsychotic polypharmacy, despite the lack of robust evidence of its efficacy, we sought to implement a pre-planned protocol where two alternative therapeutic answers are systematically provided and evaluated within the context of a pragmatic, multicentre, independent randomised study.</p> <p>Methods/Design</p> <p>The principal clinical question to be answered by the present project is the relative efficacy and tolerability of combination treatment with clozapine plus aripiprazole compared with combination treatment with clozapine plus haloperidol in patients with an incomplete response to treatment with clozapine over an appropriate period of time. This project is a prospective, multicentre, randomized, parallel-group, superiority trial that follow patients over a period of 12 months. Withdrawal from allocated treatment within 3 months is the primary outcome.</p> <p>Discussion</p> <p>The implementation of the protocol presented here shows that it is possible to create a network of community psychiatric services that accept the idea of using their everyday clinical practice to produce randomised knowledge. The employed pragmatic attitude allowed to randomly allocate more than 100 individuals, which means that this study is the largest antipsychotic combination trial conducted so far in Western countries. We expect that the current project, by generating evidence on whether it is clinically useful to combine clozapine with aripiprazole rather than with haloperidol, provides physicians with a solid evidence base to be directly applied in the routine care of patients with schizophrenia.</p> <p>Trial Registration</p> <p><b>Clincaltrials.gov Identifier</b>: NCT00395915</p
Serum Albumin Is Inversely Associated With Portal Vein Thrombosis in Cirrhosis
We analyzed whether serum albumin is independently associated with portal vein thrombosis (PVT) in liver cirrhosis (LC) and if a biologic plausibility exists. This study was divided into three parts. In part 1 (retrospective analysis), 753 consecutive patients with LC with ultrasound-detected PVT were retrospectively analyzed. In part 2, 112 patients with LC and 56 matched controls were entered in the cross-sectional study. In part 3, 5 patients with cirrhosis were entered in the in vivo study and 4 healthy subjects (HSs) were entered in the in vitro study to explore if albumin may affect platelet activation by modulating oxidative stress. In the 753 patients with LC, the prevalence of PVT was 16.7%; logistic analysis showed that only age (odds ratio [OR], 1.024; P = 0.012) and serum albumin (OR, -0.422; P = 0.0001) significantly predicted patients with PVT. Analyzing the 112 patients with LC and controls, soluble clusters of differentiation (CD)40-ligand (P = 0.0238), soluble Nox2-derived peptide (sNox2-dp; P < 0.0001), and urinary excretion of isoprostanes (P = 0.0078) were higher in patients with LC. In LC, albumin was correlated with sCD4OL (Spearman's rank correlation coefficient [r(s)], -0.33; P < 0.001), sNox2-dp (r(s), -0.57; P < 0.0001), and urinary excretion of isoprostanes (r(s), -0.48; P < 0.0001) levels. The in vivo study showed a progressive decrease in platelet aggregation, sNox2-dp, and urinary 8-iso prostaglandin F2 alpha-III formation 2 hours and 3 days after albumin infusion. Finally, platelet aggregation, sNox2-dp, and isoprostane formation significantly decreased in platelets from HSs incubated with scalar concentrations of albumin. Conclusion: Low serum albumin in LC is associated with PVT, suggesting that albumin could be a modulator of the hemostatic system through interference with mechanisms regulating platelet activation
Genomic investigations of unexplained acute hepatitis in children
Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children