92 research outputs found

    A wind tunnel two-dimensional parametric investigation of biplane configurations

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    This paper presents an experimental and systematic investigation about how geometric parameters on a biplane configuration have an influence on aerodynamic parameters. This experimental investigation has been developed in a two-dimensional approach. Theoretical studies about biplanes configurations have been developed in the past, but there is not enough information about experimental wind tunnel data at low Reynolds number. This two-dimensional study is a first step to further tridimensional investigations about the box wing configuration. The main objective of the study is to find the relationships between the geometrical parameters which present the best aerodynamic behavior: the highest lift, the lowest drag and the lowest slope of the pitching moment. A tridimensional wing-box model will be designed following the pattern of the two dimensional study conclusions. It will respond to the geometrical relationships that have been considered to show the better aerodynamic behavior. This box-wing model will be studied in the aim of comparing the advantages and disadvantages between this biplane configuration and the plane configuration, looking for implementing the box-wing in the UAV?s field. Although the box wing configuration has been used in a small number of existing UAV, prestigious researchers have found it as a field of high aerodynamic and structural potential

    Identification of Mirafiori lettuce big-vein virus and Lettuce big-vein associated virus infecting Lactuca sativa with symptoms of lettuce big-vein disease in Argentina

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    Lettuce big-vein disease (BVD) affects all major lettuce-producing areas of the world. The causal agent is Mirafiori lettuce big-vein virus (MLBVV), an ophiovirus transmitted by the soil-borne fungus Olpidium brassicae (Lot et al., 2002). MLBVV has been detected in many different areas of the world but never in Argentina. La Plata has about 700 ha of lettuce with a production of about 13 000 tonnes, and with about 70% of the total production from Buenos Aires Province. BVD has been detected in different areas in the north and west of the La Plata horticultural green belt. Many of the plants with BVD symptoms had leaf distortions of moderate severity, which affected their commercial value.Facultad de Ciencias ExactasFacultad de Ciencias Agrarias y Forestale

    Life history baseline of unexploited populations: The case of Beryx splendens from the Sierra Leone Rise

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    This study examines for the first time the biology of alfonsino (Beryx splendens) from three small seamounts of the Sierra Leone Rise (SLR), an unexploited and fragile ecosystem in the Atlantic, using data from an experimental survey carried out in 2001 by Spanish longliners. In general, the lack of rigorous baseline data limits the implementation of efficient management and conservation plans in fisheries strategies. Therefore, the main aim of present study was to provide baseline information on basic biological parameters of the alfonsino population associated with an unexploited ecosystem. A total of 17296 individuals of alfonsino were sampled from SLR. Alfonsino is gonochoric and presented an unbalanced sex ratio, there were significantly more females than males. Taking into account the results in stage of maturity of alfonsino and the gonadosomatic index values during studied period, we can conclude that at least one reproductive period in these seamounts was in the late spring and early summer. The spawning stage was attained at a minimum fork length of 23 and 25 cm for males and females, respectively. The size at which 50% of the population attains sexual maturity was approximately 28 and 27 cm for males and females, respectively. The stock structure of alfonsino showed a segregation of the size with the depth, as they increase in size they move into the deeper water.Versión del edito

    Identification of Mirafiori lettuce big-vein virus and Lettuce big-vein associated virus infecting Lactuca sativa with symptoms of lettuce big-vein disease in Argentina

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    Lettuce big-vein disease (BVD) affects all major lettuce-producing areas of the world. The causal agent is Mirafiori lettuce big-vein virus (MLBVV), an ophiovirus transmitted by the soil-borne fungus Olpidium brassicae (Lot et al., 2002). MLBVV has been detected in many different areas of the world but never in Argentina. La Plata has about 700 ha of lettuce with a production of about 13 000 tonnes, and with about 70% of the total production from Buenos Aires Province. BVD has been detected in different areas in the north and west of the La Plata horticultural green belt. Many of the plants with BVD symptoms had leaf distortions of moderate severity, which affected their commercial value.Facultad de Ciencias ExactasFacultad de Ciencias Agrarias y Forestale

    Biology (growth and reproduction) of the Mediterranean deep-water rose shrimp (Parapenaeus longirostris (Lucas, 1846), Crustacea, Decapoda) from the Alicante Gulf (s.e. Spain).

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    The deep-water rose shrimp (Parapenaeus longirostris) is a demersal species and an important resource for the trawl fishery in the Alicante Gulf (S.E. Spain). This paper describes, for first time in this area, certain biometric relationships, as well as growth parameters and reproductive patterns of the species. The results showed a sexual size dimorphism, with a negative allometry of relative growth and high rates of absolute growth, both particularly in males. However, females dominated in the catch proportion. The spawning period occurred throughout the year, but especially in June-July and in October-November and the maturation stage for females takes place within the second year of life

    Bathyal megabenthic assemblages in the SE Iberian Peninsula (Western Mediterranean Sea)

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    The Iberian SE is an interesting transition and connectivity zone between the Alboran Sea and the Algerian-Balearic basin. It hosts important deep water fisheries targeting mostly red shrimp (Aristeus antennatus). The area comprises a complex system of tectonic canyons (Mazarron Escarpment), seamounts, knolls and hills (Palos, Planazo, Plis-Plas), and pockmark fields (Acosta et al., 2013). Few studies have been conducted on the bathyal megabenthos, unlike in the neighbouring Chella Bank (De la Torriente et al. 2018) and Balearic Islands (Massuti et al. 2022). The LIFE IP Intemares project is filling this gap

    Vulnerable Marine Ecosystems found in a bathyal zone off the SE Iberian Peninsula (Western Mediterranean)

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    The Spanish Intemares LIFE IP project contemplates the creation of Special Areas of Conservation within the Natura 2000 Network. During its August 2019 cruise, a series of towed sledge transects were conducted on two seamounts (“Planazo” and “Plis Plas”) and a muddy field of pockmarks, both located in areas off the SE Iberian Peninsula (Western Mediterranean), between 220 and 694m depth. The prospected area has a significant pressure from bottom trawl (directed towards Aristeus antennatus, Nephrops norvegicus, Plesionika spp.) and, to a smaller extent, of bottom longline fisheries (focused on Merluccius merluccius and Pagellus bogaraveo). Some of the observed bathyal habitats fall into the category of Vulnerable Marine Ecosystems (VME), according to FAO (2009, 2016), since they present at least one of the following characteristics: i) uniqueness or rarity; ii) functional significance of habitat; iii) fragility; iv) life history traits of component species that make recovery difficult; and/or v) structural complexity. Among them, “gorgonian gardens” (of Paramuricea hirsuta, Callogorgia verticillata, Bebryce mollis, Swiftia pallida, and Ellisella flagellum) and the yellow tree coral (Dendrophyllia cornigera) highlight rocky bottoms; while on muddy substrates, sea-pen fields (Funiculina quadrangularis and Kophobelemnon stelliferum) and “bamboo coral gardens” (Isidella elongata) do so. These habitats, along with fields of the crinoid Leptometra phalangium, are also considered Essential Habitats for target species of fishing interest. The location, mapping and characterization of these habitats are necessary to establish “no-take” zones within the future management plan for the area studied

    Influenza A H1N1 Community-Acquired Pneumonia: Characteristics and Risk Factors—A Case-Control Study

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    Introduction. Influenza A H1N1 community-acquired pneumonia (CAP) is a quite frequent respiratory disease. Despite being considered more serious than other CAPs, there are very few studies comparing its characteristics with noninfluenza CAP. We aim to establish the differences between pneumonia due to H1N1 virus and pneumonia not caused by H1N1 influenza virus and to determine the probability that a pneumonia is due to an H1N1 virus infection based on the most relevant variables. Methods. We used a case-control study where cases were H1N1 CAP patients with confirmed microbiological diagnosis and controls were patients with CAP admitted to hospital. H1N1 and other influenza types were discarded among controls. We calculated the probability of being a case or control using multivariate logistic regression. Results. We included 99 cases and 270 controls. Cases were younger than controls (53 vs 71 years, respectively). Mortality was much higher for H1N1 patients (13% vs 0.3%), and admission to intensive care unit was more frequent for H1N1 cases. The variables most associated with presenting H1N1 CAP were bilateral affectation on chest X-rays (OR: 5.70; 95% CI 2.69–10.40), followed by presence of arthromyalgias, with cases presenting close to three times more arthromyalgias compared to controls. Low leukocytes count and high AST values were also significantly associated with H1N1 CAP. H1N1 CAPs are characterized by bilateral affectation, low leukocyte count, presence of arthromyalgias, and high AST. Conclusions. A few and easy to obtain clinical parameters might be extremely useful to distinguish H1N1 CAP from CAPs of other origin.S

    Interleukin 27 could be useful in the diagnosis of tuberculous pleural effusions

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    BACKGROUND: The diagnosis of tuberculous pleural effusion (TBPE) has some limitations. We studied the efficacy of interleukin-27 (IL-27) in the diagnosis of TBPE. METHODS: We measured IL-27, adenosine deaminase (ADA), ADA-2, interferon-gamma (IFNgamma), and the ADA.IL-27 and ADA-2.IL-27 products in all the pleural effusion fluids. The diagnostic yield of IL-27 was evaluated with receiver operating characteristic curves. RESULTS: Of 431 pleural effusions, 70 were tuberculous, 146 were neoplastic, 58 were parapneumonic, 28 were empyemas, 88 were transudates, and 41 were other types. With a cutoff point of 0.55 ng/mL, IL-27 had a sensitivity of 91.4% and a specificity of 85.1%, which were significantly less than ADA, ADA-2, IFNgamma, ADA.IL-27, or ADA-2.IL-27. The area under the receiver operating characteristic curve for IL-27 (0.963) was also significantly lower than that for the other markers, except for IFNgamma. However, IL-27 improved the sensitivity of ADA and ADA-2 through ADA.IL-27 and ADA-2.IL-27 products (100% for both). CONCLUSIONS: IL-27 is less efficient than ADA and ADA-2 in the diagnosis of TBPE. However, ADA.IL-27 and ADA-2.IL-27 improve the diagnostic sensitivity of ADA and ADA-2, and thus could be useful in situations of high clinical suspicion and low ADA level. A value above the cutoff point of the latter is practically diagnostic of TBPE

    Bathyal megabenthic assemblages in the south-eastern Iberian Peninsula (Western Mediterranean)

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    The SE Iberian sector represents an interesting transition and connectivity zone between the Alboran Sea and the Algerian Balearic basin, and the area comprises a system of tectonic canyons (Mazarron Escarpment), seamounts and pockmarks fields. Despite this, relatively few studies have been conducted on the bathyal zone. During the LIFE IP Intemares A2.2-Mu0820 survey, the continental slope was observed by ROV Liropus-2000, between 183 and 1735m depth following bathymetric mapping using a multibeam echosounder. A combination of multivariate analysis of still imagery and video groundtruthing have been able to discriminate some megabenthic assemblages. On hard bottoms of the upper bathyal horizon: i) Neopycnodonte cochear-Mergelia truncata facies, 193-244m depth; ii) Ellisella flagellum facies, 2441-320m; iii) Antipathes dichotoma facies, 259-270m. Middle horizon: i) Demospongiae facies (Pachastrella, Phakellia, Aaptos…), 241-494m; ii) gorgonian assemblage (Callogorgia, Paramuricea, Placogorgia), 294-624m; iii) Leptometra phalangium facies 293-611m; iv) cold-water corals (Desmophyllum, Madrepora), 516-607m; Antipatharia facies (Antipathella, Leiopathes, Parantipathes), 519-624m. Lower bathyal horizon:; Dicopia antirrhinum facies, 645-1167m. On soft bottoms (mud, sandy-mud) of the upper bathyal horizon: i) Ceriantharia facies, 213-219m depth. Middle horizon: i) Pennatulacea facies (Funiculina, Kophobelemnon, Pteroeides…), 219-541m; ii) Thenea muricata facies, 418-814m; iii) Isidella elongata facies, 462-681m. Lower horizon: i) Pelosina fields, 235-1321m. The results reveals that the bathyal zone of the SE Iberian Peninsula is topographically complex and harbours diverse benthic assemblages, some of which fall within the category of Vulnerable Marine Ecosystems; and some species are listed in annex II of the RAC/SPA list of endangered or threatened species
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