1,876 research outputs found

    Semi-empirical analysis of Sloan Digital Sky Survey galaxies III. How to distinguish AGN hosts

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    We consider the techniques to distinguish normal star forming (NSF) galaxies and active galactic nuclei (AGN) hosts using optical spectra. The observational data base is a set of 20000 galaxies extracted from the Sloan Digital Sky Survey, for which we have determined the emission line intensities after subtracting the stellar continuum obtained from spectral synthesis. Our analysis is based on photoionization models computed using the stellar ionizing radiation predicted by Starburst 99 and, for the AGNs, a broken power-law spectrum. We explain why, among the four classical emission line diagnostic diagrams, the [OIII]/Hb vs [NII]/Ha one works best. We show however, that none of these diagrams is efficient in detecting AGNs in metal poor galaxies, should such cases exist. We propose a new divisory line between ``pure'' NSF galaxies and AGN hosts. We also show that a classification into NSF and AGN galaxies using only [NII]/Ha is feasible and useful. Finally, we propose a new classification diagram, the DEW diagram, plotting D_n(4000) vs max(EW[OII],EW[NeIII]). This diagram can be used with optical spectra for galaxies with redshifts up to z = 1.3, meaning an important progress over classifications proposed up to now. Since the DEW diagram requires only a small range in wavelength, it can also be used at even larger redshifts in suitable atmospheric windows. It also has the advantage of not requiring stellar synthesis analysis to subtract the stars and of allowing one to see ALL the galaxies in the same diagram, including passive galaxies.Comment: 14 pages, 9 figures, accepted for publication in MNRAS (replaced on august 3, 2006, eqs 6 and 7 corrected

    Robotics and entrepreneurship for a better society: opening doors to mobility

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    This article reports the development of an educational robotics project at the Basic School (2nd and 3rd cycles) André Soares in Braga, with students from 6th grade, integrated in an international cooperative partnership for innovation and good practices of the European Erasmus+ programme. This project was initially designed to address the need to share innovative teaching practices through the development of new methodologies and multidisciplinary approach in teachinglearning processes in the 2nd and 3rd cycles of basic education combined with the stimulation of entrepreneurial skills and co-creation of knowledge. From the beginning, the project had the collaboration and support of the Hands-on Science Network Association, having given rise to the submission of an application to the 13th edition of the contest “Projeto Ciência na Escola” of the Ilídio Pinho Foundation on the topic “Science and Technology at the service of a better world”. This application has been selected for the 2nd phase of the competition and obtained financial support for the development of activities which gave an added dimension to the project, attracting and further motivating students for learning science and the choice of technology areas. Students were challenged to identify a situation/problem and find a possible solution/answer in the context of educational robotics. Thus, there was the study of the LEGO MINDSTORMS NXT programming environment for programming routines or scripts and simultaneously the work methodology hands-on was implemented using participative methodological approaches, enhancing the development of key skills and entrepreneur spirit. At first, students’ creativity was stimulated through the ideas generation process called SCAMPER, channelling it to solve situations/problem where the students' task was to unlock a situation and optimize it. From a simple stick and a simulation of a path for blind people, ideas were collected to innovate this object, in order to promote a more efficient and fairer mobility. With the collection/gathering of ideas/suggestions, a guiding principle for our project was developed giving an intended metacognitive knowledge. Starting with the acquisition of this knowledge, students focus on building and programming robots LEGO MINDSTORMS NXT, developing the prototype of a smart and innovative cane for the blind people. This is an interactive process that combines the concrete and the abstract in solving a problem involving steps such as: design, implementation, construction, automation and control mechanism. In all of these steps the construction of knowledge took place, arising from different scientific fields (science, mathematics, physics, technology), as well as the acquisition of transversal skills. The work focused mainly on the dynamics of the process rather than the products or results. Many citizenship skills were developed when creating a tool to minimize the difficulties and obstacles faced by blind people, enabling the improvement of their quality of life. It was observed, from certain experimental activities, that one can transfer new skills and knowledge acquired at school to everyday life

    Possible respiratory infection due to Aspergillus in workers from swineries and poultries

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    Introduction: Aspergillus is among a growing list of allergens that can aggravate asthmatic responses. Significant pulmonary pathology is associated with Aspergillus-induced allergic and asthmatic lung disease. Environments with high levels of exposure to fungi are found in animal production facilities like swineries and poultry which farmers are at increased risk of occupational respiratory diseases. Purpose: Seven Portuguese poultries and seven swineries were analyzed in order to estimate the prevalence, amount and distribution of Aspergillus species, as well as to evaluate the existence of clinical symptoms associated with asthma and other allergy diseases in these highly contaminated settings. Methods: A total of 83 air samples (through impaction method), 66 surface samples (swab sampling) and 28 samples of different material covering their floor were analyzed. Results: The collected fungal isolates (699) were distributed by 40 different genus, Aspergillus presented a prevalence of 17.6% (average) and regarding poultries only, its prevalence showed a higher value (22.7%). The most frequently isolated Aspergillus species were A. versicolor, A. flavus and A. fumigatus. In poultries, A. flavus presented the highest level of airborne spores (>2000 ufc/m3) whereas in swineries was A. versicolor, with a prevalence four times higher than the other referred species. Eighty workers of these settings were analyzed, with ages ranging from 17 to 93 years old. Seven of these workers were medical diagnosed with asthma and four of them reported the first attack after the age of 40 years old, which possibly could be related with their occupational exposure. A high prevalence of respiratory symptoms in professionals without asthma was observed, namely wheezing associated with dyspnea (23.8%) and dyspnea after strenuous activities (12.3%), suggesting an under diagnosed respiratory problem. Moreover, 32.5% of all the inquired workers refer an improvement of their respiratory ability during the resting days and holiday. Conclusions: Considering the strong association between fungal sensitization and severity of asthma and that Aspergillus species are one of the most important fungal agents causing sensitization of the individual, this study contributes to the knowledge of Aspergillus prevalence and distribution in Portuguese poultries and swineries. These data, together with data regarding determinations of specific IgE levels and monitorization of mycotoxin exposure using biomarkers will also help to understand how and which Aspergillus species can affect workers of these settings

    Economic valuation of life cycle environmental impacts of construction products - A critical analysis

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    The aim of this paper is to identify existing methods for economic valuation or monetisation of life cycle environmental impacts and to assess its applicability in the broad European context. Although environmental awareness is more and more important in several industrial sectors, including the construction sector, easy to understand data are still missing for professionals to assess and manage impacts related to the whole life cycle of a building. Life Cycle Assessment (LCA) is one of the most commonly accepted methodologies to calculate potential life cycle environmental impacts of a product or service. However, the results of such method, even when published in an Environmental Product Declaration, meant for business to business communication, are not always comparable or easily understandable by non-practitioners. Economic valuation or monetisation of LCA results is a weighting step that can make it easier for non-practitioners to use LCA results to support decision-making. From the several monetisation methods analysed, it is discussed the one that is most suitable for use when LCA results already exist. It is concluded that further work is needed to improve such weighting methods or develop a common one that can be representative at a broader geographical level (for instance, Europe-wide).This work was supported by FCT - Fundação para a Ciência e Tecnologia [grant number PD/BD/127850/2016] under the Doctoral Program EcoCoRe - Eco-Construction and Rehabilitation. Support from CERIS and Instituto Superior Técnico is also acknowledged

    Calf muscle stimulation with the Veinoplus device results in a significant increase in lower limb inflow without generating limb ischemia or pain in patients with peripheral artery disease

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    OBJECTIVE: Increase in arterial inflow to the lower limbs is important to obtain functional improvement in peripheral artery disease (PAD) patients with claudication. The aim of this study was to assess the effect of electrical stimulation of calf muscles on arterial inflow and tissue oxygen content in PAD in the area of stimulation.METHODS: Fifteen adult patients [mean (standard deviation) age, 62 (12 ) years; height, 165 (8)cm; weight, 76 (13) kg; lowest ankle-brachial index 0.66 (0.19)] with stable arterial claudication were recruited. All patients performed a treadmill test (3.2 km/h, 10% slope) associated with a transcutaneous oximetry test expressed as decrease from rest of oxygen pressure (DROP) index values (calf changes minus chest changes from rest) with a maximum walking distance (median [25th/75th percentiles]) of 295 [133-881] m. The DROP index on the symptomatic side was -25 [-18/-34] mm Hg. On another day the patients underwent electrical stimulation in the seated position on the leg that was the most symptomatic on the treadmill. After resting values were recorded, the gastrocnemius was stimulated for 20minutes at increasing contraction rates at 5-minute steps of 60, 75, 86, and 100bpm on the most symptomatic side. Arterial blood inflow with duplex Doppler ultrasound scanning of the femoral artery, DROP transcutaneous oxygen pressure value, and oxygen concentration (O2Hb) from the near-infrared spectroscopic signal of the calf were recorded on both sides. Patients were instructed to report eventual contraction-induced pain in the stimulated calf. Results are given as mean (standard deviation) or median [25th/75th percentiles] according to distribution, and the level of statistical significance was set at P < .05 on two-tailed tests. RESULTS: Lower limb inflow (mL/min) was 64 [48/86] vs 63 [57/81] (P> .05) before stimulation, 123 [75/156] vs 57 [44/92] (P < .01) at 60bpm, 127 [91/207] vs 49 [43/68] (P < .01) at 75bpm, 140 [84/200] vs 57 [45/71] (P < .01) at 86bpm, and 154 [86/185] vs 55 [46/94] (P < .01) at 100bpm on the stimulated vs nonstimulated limb, respectively. No apparent decrease or significant leg difference was observed in DROP index or O2Hb values. None of the patients reported contraction-induced pain in the leg. CONCLUSIONS: Electrical stimulation of calf muscle with the Veinoplus device results in a significant increase of arterial inflow without measurable muscle ischemia or pain. Potential use of this device as an adjuvant treatment to improve walking capacity in PAD patients remains to be evaluated
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