641 research outputs found

    In operando XAS investigation of reduction and oxidation processes in cobalt and iron mixed spinels during the chemical loop reforming of ethanol

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    FeCo2O4 and CoFe2O4 nanoparticles have been studied as oxygen carriers for the Chemical Loop Reforming (CLR) of ethanol. By using in operando X-ray absorption spectroscopy we have followed in real time the chemical and structural changes that take place on the materials as a function of temperature and reactive atmosphere (i.e. ethanol/water streams). During the first step of CLR for both oxides the most active chemical species are the cations in the tetrahedral sites, irrespective of their chemical nature. Quite rapidly the spinel structure is transformed into a mix of wustite-type oxide and metal alloys, but the formation of a metal phase is easier in the case of cobalt, while iron shows a marked preference to form wustite type oxide. Despite the good reducibility of FeCo2O4 imparted by the high amount of cobalt, its performance in the production of hydrogen is quite poor due to an inefficient oxidation by water steam, which is able to oxidize only the outer shell of the nanoparticles. In contrast, CoFe2O4 due to the residual presence of a reducible wustite phase shows a higher hydrogen yield. Moreover, by combining the structural information provided by X-ray absorption spectroscopy with the analysis of the byproducts of ethanol decomposition we could infer that FeCo2O4 is more selective than CoFe2O4 for the selective dehydrogenation of ethanol to acetaldehyde because of the higher amount of Fe(III) ions in tetrahedral sites

    The genetic status of Sorocea bonplandii in the highly fragmented forest in southern Brazil.

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    Sorocea bonplandii is a dioecious sub canopy plant species with an abundant and widespread distribution in the Atlantic Forest, Southern Brazil. It is traditionally used for art crafts and popular medicine. We have investigated the genetic status of S. bonplandii in one large and six small populations of the fragmented Atlantic Forest in southern Brazil. In spite of population fragmentation, the allozyme electrophoretic analysis involving 23 loci of 12 enzymes from 420 plants revealed unusually high frequencies of heterozygous genotypes and a balanced distribution, in agreement with Hardy-Weinberg proportions. Very little genetic differentiation among populations was detected. The observed excess of heterozygotes suggests that selection favors heterozygous plants. Although S. bonplandii is a dominant sub-canopy species which strongly depends on ombrophilous environmental conditions, its genetic structure and diversity do not appear to suffer with forest fragmentation. All of these characteristics, in addition to its medicinal uses, suggest that this species is a potential resource for sustainable management of tropical forests in southern Brazil

    Verifying big data topologies by-design: a semi-automated approach

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    Big data architectures have been gaining momentum in recent years. For instance, Twitter uses stream processing frameworks like Apache Storm to analyse billions of tweets per minute and learn the trending topics. However, architectures that process big data involve many different components interconnected via semantically different connectors. Such complex architectures make possible refactoring of the applications a difficult task for software architects, as applications might be very different with respect to the initial designs. As an aid to designers and developers, we developed OSTIA (Ordinary Static Topology Inference Analysis) that allows detecting the occurrence of common anti-patterns across big data architectures and exploiting software verification techniques on the elicited architectural models. This paper illustrates OSTIA and evaluates its uses and benefits on three industrial-scale case-studies

    The strong and the hungry: Bias in capture methods for mountain hares (Lepus timidus).

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    Estimating density, age and sex structure of wild populations is a key objective in wildlife management. Live trapping is frequently used to collect data on populations of small and medium-sized mammals. Ideally, sampling mammal populations by live capturing of individuals provides a random and representative sample of the target population. Trapping data may, however, be biased. We used live-capture data from mountain hares Lepus timidus in Scotland to assess sampling bias between two different capture methods.Wecaptured hares using baited cage traps and long nets on five study areas in the Scottish Highlands. After controlling for the effects of body size, individuals caught in traps were lighter than individuals caught using long nets, suggesting that the body condition of hares differed between the capture methods. This tendency may reflect an increased risk-taking of individuals in poorer body condition and less aversion to entering traps in order to benefit from eating bait. Overall, we caught more adult hares than juveniles and more female hares than males. Our results show that estimates of density and population structure of mountain hares using livecapture data could be affected by the capture method used. We suggest that live-capture studies employ more than one capture method and test for heterogeneity in capture probability to minimise potential bias and achieve reliable estimates of population parameters

    Mapping Asbestos-Cement Roofing with Hyperspectral Remote Sensing over a Large Mountain Region of the Italian Western Alps

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    The World Health Organization estimates that 100 thousand people in the world die every year from asbestos-related cancers and more than 300 thousand European citizens are expected to die from asbestos-related mesothelioma by 2030. Both the European and the Italian legislations have banned the manufacture, importation, processing and distribution in commerce of asbestos-containing products and have recommended action plans for the safe removal of asbestos from public and private buildings. This paper describes the quantitative mapping of asbestos-cement covers over a large mountainous region of Italian Western Alps using the Multispectral Infrared and Visible Imaging Spectrometer sensor. A very large data set made up of 61 airborne transect strips covering 3263 km2 were processed to support the identification of buildings with asbestos-cement roofing, promoted by the Valle d’Aosta Autonomous Region with the support of the Regional Environmental Protection Agency. Results showed an overall mapping accuracy of 80%, in terms of asbestos-cement surface detected. The influence of topography on the classification’s accuracy suggested that even in high relief landscapes, the spatial resolution of data is the major source of errors and the smaller asbestos-cement covers were not detected or misclassified

    Home range dynamics of mountain hares (Lepus timidus) in the Swiss Alps.

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    Little is known on the ecology and behaviour of the alpine mountain hare (Lepus timidus). Between 1996 and 1997, we analysed by radiotracking the pattern of space use of 8 mountain hares from the Swiss Alps. We estimated home range size using both the kernel density estimator and the minimum convex polygon. We found smaller ranges (38 ha) compared to those reported for the species in boreal or arctic habitats, but similar to ranges in Scotland. Hares did not use a centre of major activity (core area) and showed high home range overlap, confirming their non-territorial behaviour. Smaller ranges were used during winter compared to the other seasons, whilst no difference in size was found between sexes

    Primary Absence of Type II Endoleak is A Positive Prognostic Factor against the Risk of Late Conversion of EVAR for AAA

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    Introduction: The aim of this study is to analyze 12 late conversion to open surgery after Endovascular Repair of Abdominal Aortic Aneurysms (EVAR) while comparing the follow up of these cases to that of the definitely successful procedures (absence of surgical conversion, type I or III endoleaks, or presence of type II endoleaks without any aneurysmal sac enlargement) . Methods: From a series of over 300 EVAR procedures performed at our department we have selected 215 cases with a follow up ≥ 6 month and primary technical success (successful deployment of the devices and discharge of patients without neither type I nor III endoleaks). Based on the final data recorded at the end of the follow up (mean+ IQR: 38.16 months + 41), these cases were divided into three groups: group 1, with 12 cases (5.6%) which needed surgical conversion in a later stage (5 to 55 months from EVAR); group 2, with 39 cases (18.1%) with type II endoleaks without aneurysmal sac enlargement; group 3, with 164 cases (76.5%) without endoleaks. The groups were compared in relation to the following parameters: a) personal data and common atherogenic risk factor, b) diameter of the aneurysm, c) kind of the proximal fixation of the endograft (suprarenal or infrarenal), d) presence of endoleaks at the first postoperative check. We have compared the data from the three groups and we have analyzed them with chi-square test (Χ2). Results: Personal data and common atherogenic risk factor have proved no significant difference among the three groups. The incidence of the other three parameters of group 1 was compared with the incidence of these in groups 2 and 3: the mean pre-operative diameter of the aneurysm results 51 mm in group 1, 54 mm in group 2 and 55 mm in group 3 (not significant); suprarenal fixation of the prosthesis accounts for 50% in group 1, 51% in group 2 and 60% in group 3 (not significant); presence of type II endoleak at the first post-operative check was 41.6% in group 1, 56.4% in group 2 (not significant) and 9.7% in group 3 (p<0.001, compared to groups 1 and 2). Conclusion: In the EVAR procedures with primary technical success, the absence of type II endoleak at the first post-operative check represents a favorable prognostic factor against the risk of late conversion to open repair. Personal data, common atherogenic risk factor, diameter of the aneurysm and fixing type of the prosthesis don’t seem to influence the onset of this complication

    Competências adquiridas no Curso de Graduação em Administração de Empresas sob a ótica dos alunos formandos

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    Considerando a existência das diretrizes curriculares para os cursos de Administração, este estudo procura compreender se as Instituições de Ensino Superior, na percepção dos alunos formandos, têm conseguido desenvolver os conhecimentos, habilidades e atitudes sugeridos por tais diretrizes ao longo do curso de graduação, permitindo reflexões ao corpo docente. Para compreender essa realidade, foi aplicada uma pesquisa aos acadêmicos do último ano do Curso de Graduação em Administração da Faculdade Marechal Rondon (FMR), localizada em São Manuel, interior do estado de São Paulo. A pesquisa contribuiu para esclarecer que, de maneira geral, a percepção dos discentes é que a FMR tem conseguido desenvolver conhecimentos, habilidades e atitudes sugeridos pelas diretrizes curriculares; entretanto, a pontuação cai quando as competências são relacionadas à gestão de projetos e prestação de consultorias. O corpo docente, por sua vez, deve refletir sobre o resultado e reavaliar atividades curriculares, principalmente as complementares, que oferecem palco valioso para o aprimoramento dos administradores egressos. Palavras-chave: Competências. Diretrizes curriculares. Ensino em Administração
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