744 research outputs found

    A Graph-based Technique for Higher Order Topological Data Structure Visualisation

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    Esta publicação foi agraciada com o prémio GISRUK 2005 “Whittles Publishing” Best Paper Award.Interpretation and analysis of spatial phenomena is a highly time consuming and laborious task in several fietds of the Geomatics world (Anders et al., 1999). That is why the automation of those tasks is especially needed in areas such as Geographical Information Science (GlScience). Carrying out these tasks in the context of an urban scene is particulariy challenging given its complexity: relatively small component elements and itt"it g"nrially complei spatial pattern (Eyton, 1993, and Barr & Barnsley, 1996, both cited in Barnsley and Barr, 1997). Topology is a particularly important research area in the field of GlScience, for it is a central àefining feature of a geographical information system (GIS). But, as far as topological relàtionships between spatial objects are concerned, "generally speaking .ottt.Àporary desktop bIS packages do not support further information beyond the first level oi adjâcency" (Theobald, 2001). Therefore, this research project focused on scene analysis bi buiiding up a technique for the better understanding of topological relationships between vector-based GIS objects, beyond the fnst level of adjacency. Another initial interest was to investigate the possible use of graph theory for this purpose. To date, this mathematical framework has been used in different applications in a wide range of fields to represent connections and relationships between spatial entities. Several u,rtùo6 (including Laurini and Thompson, 1992) have maintained that "this particular tool is extremely valuable and efficient in storing and describing the spatial structure of geographicil entities and their spatial arrangement". Theobald (2001) added that "concepts àf gruptt theory allow us to extend the standard notion of adjacency". The aim of retrieving structured information translated into more meaningful homogeneous regions, for instancJ fro* an initial unstructured data set, may be achieved by identifuing mJaningful structures within the initial random collection of objects and by understanding the spatial arrangement between them. We believe that applying graph theory and carrying out graph analysis may accomplish this

    A Singular Conformal Spacetime

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    The infinite cosmological "constant" limit of the de Sitter solutions to Einstein's equation is studied. The corresponding spacetime is a singular, four-dimensional cone-space, transitive under proper conformal transformations, which constitutes a new example of maximally-symmetric spacetime. Grounded on its geometric and thermodynamic properties, some speculations are made in connection with the primordial universe.Comment: RevTeX4, 10 pages, 1 eps figure. Presentation changes, including a new title; section II.E, on the thermodynamic properties of the de Sitter horizon, completely revised. Version to be published in Journal of Geometry and Physic

    The striped soldier shrimp Plesionika edwardsii (Crustacea:Decapoda:Pandalidae) from the cape Verde Islands

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    This study is part of the PROACTIVA 1-2 (2009-2012) and MARPROF-CV (2010-2014) projects, in the framework of the Canary Islands Government and UE PCT MAC 2007-2013 programmes respectively. Research has mainly focused on the stock assessment of the striped soldier shrimp, Plesionika edwardsii (Brandt, 1851), because it has shown moderate to high levels of fishing yield and abundances compatible with the development of a new sustainable fishery in the Cape Verde Islands. Cruises took place on board the R/V Prof. Ignacio Lozano. Four 15-day surveys have been conducted to date: Cabo Verde 2010-04 (April 2010), Camar˜ao-1 (November 2011), Camar˜ao-2 (Mars 2012) and Camar ˜ao-3 (July 2012). An innovative fishing gear so-called multiple semi-floating shrimp trap (MSFST) was used. Each fishing line was composed by 40-65 traps operating around 2.4 m above the seafloor, using Decapterus macarellus (Carangidae) as unique bait of the traps. Fishing depth was 66-458 m, and efective fishing time was 16-18 h. Each trap was attached to the main bottom line every 15 m, and the maximum attraction of this bait was established to be 100 or 150 m, according to the experience gained from the local fishery for deep-sea lobsters. So density by area was calculated assuming two different areas of attraction of the fishing gear. Initial biomass was estimated from depletion experiments at different abundance stations by applying the Leslie & Davis (1939) method, modified by Ricker (1975). Each fishing operation was classified according to its yield (CPUE in g/trap/night). The potential fishing planar area was estimated between the isobathymetric lines between 90 and 220 m. Total biomasses (Bt) were calculated from areas (km2) and mean minimum/maximum densities (kg/km2). Maximum sustainable yield (MSY) was estimated from Bt using the Beddington and Cooke (1983) model by entering natural mortality (0.6), growth rate (0.53 year�1) and recruitment age (1.32 year), which are the parameters for this target species published for the Canaries. These parameters estimate a biological exploitation rate ( ) of 0.262. Interpolations were applied to estimate MSY for insular stocks representing lesser than 5% of the total fishing grounds for this species in the archipelago. The MSY estimated by depletion were 30.5 tons/year for the stock of S˜ao Vicente, Santa Luzia, Ilheus and S˜ao Nicolau, 10 tons/year for the stock of Santiago, 138.8 tons/year for the stock of Boa Vista and Maio, and 5.6 tons/year for the stock of Sal. The small stocks estimated by interpolation were: 4.5 tons/year for the stock of Santo Ant˜ao, 1.3 tons/year for the stock of Fogo, and 1.8 tons/year for the stock of Brava and Ilheus. In total, 192.5 tons per year was the total MSY for the striped soldier shrimp around the islands of the Cape Verde archipelago, occupying a total area of 1,918 km2 of new fishing grounds at between 90 and 220 m of depth. In comparison with the traditional bottom trap used in the Canary Islands, the innovative fishing gear MSFST were proved to be more selective for pandalid shrimps, minimizing the gear impact on the seafloor as well as the by-catch by reducing the discards. Depletion methods are based on the assumption of a closed system, that is with minimum or zero immigration between neighbouring areas. The straight forward decline of CPUEs obtained during the depletion experiments seems to confirm that P. edwardsii is a low mobility species, making this assumption valid at least during short-time periods. Because of the bathymetry profile of these islands,the depth range is from very close (few nautical miles in Santiago) to far away (10-12 n.m. in Boa Vista) to the coastline. Fishing effort should be controlled on the basis of quotas, number of fishing vessels and a precautionary approach in order to ensure that catching is commensurate with sustainable levels of exploitation. MSY estimates suggest that this new Capeverdean fishery should be carried out by specialized medium-sized fishing vessels. During the last decades a combination of shrimp trawling and industrial trapping activity has threatened over-exploitation in the Mediterranean fisheries targeting on P. edwardsii; currently the shrimp collapse has conducted to the decline of these fisheries. Can the Cape Verde regulatory bodies and all the stakeholders involved learn the lessons this teaches us about this resource management

    By-catch composition of the striped soldier shrimp Plesionika edwardsii (Crustace: Decapoda: Pandalidae) experimental fishery in the Cape Verde Islands

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    This work focuses on the by-catch composition of Plesionika edwardsii experimental fishery in the Cape Verde Islands. Obtaining information on abundance, composition and lifecycle of species involved in this potential fishery is useful, in order to ensure its sustainable development under an ecosystem approach. The first step towards this goal is the description of catches. Four 15-day research surveys were conducted on board the R/V Prof. Ignacio Lozano: April 2010 (S˜ao Vicente and Santa Luzia islands), November 2011 (Santiago island), March 2012 (Boa Vista island,) and July 2012 (Sal and S˜ao Nicolau islands). The working depths were between 66 and 458 m depth. A standardized innovative fishing gear was used, so-called multiple semi-floating shrimp traps. Each fishing line was composed by 40-65 traps operating around 2.4 m above the seafloor, using Decapterus macarellus (Carangidae) as unique bait of the traps. Multiple semi-floating shrimp traps is a passive fishing system that allows catch and release sea significant part of the unwanted catches, as in the case of Chondrichthyes or Anguilliformes, reducing the fishing impact on non-target species. The main by-catch was composed of 53 species belonging to three groups including Chondrichthyes (three families and three species), Crustacea (11 families and 19 species) and Osteichthyes (15 families and 29 species). Plesionika edwardsii, the target species of this fishery, represented 97.8% of the catch in terms of abundance and 40.1% in biomass. By-catch represented 59.9% of total catch in terms of biomass. Osteichthyes (87.5%) were the dominant group and was represented by the following main families; Sparidae (33.9%), Moridae (32.5%), Muraenidae (32.5%), Scorpaenidae (9.9%) and Tetraodontidae (9.8%). Chondrichthyes (11.6%) were composed by Centrophoridae (65.3%) and Triakidae (34.1%). Finally, Crustacea (1.9%) were chiefly composed by Pandalidae (79.1%). However, different families represented by specific species were found to be dominant around each island. Sparidae were the dominant family represented by Pagellus acarne (46.2% of total by-catch) at S˜ao Vicente, and by Dentex macrophthalmus (42.6%) at Boa Vista. Tetraodontidae with Sphoeroides pachygaster (25.9%) and Sparidae with P. acarne (25.1%) were the co-dominant families in the by-catch around Santa Luzia. Muraenidae were the dominant family represented by Gymnothorax polygonius (69.4%) at Sal, and by Muraena helena (63.4%) at S˜ao Nicolau. Finally, Scorpaenidae with Pontinus kuhlii (22.3%) and Moridae with Physiculus cyanostrophus (22.1%) were the co-dominant families of the bycatch around Santiago. Acknowledgements: This study is part of the PROACTIVA 1-2 (2009-2012) and MARPROF-CV (2010-2014) projects, in the framework of the Canary Islands Government and UE PCT MAC 2007- 2013 programmes respectively

    Effect of feed deprivation during the post hatch holding birth time on the performance of broiler chicks from breeders of different age

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    The present research work hás been carried out in order to evaluate on the post born period of broilers from different broiler breeders age, the effect of feed deprivation between hatching and housing, on feed intake, weight gain, feed conversion and viability up to 42 days old, and weight lost. A total of 480 male chicks were distributed in a randomized factorial design of 3 X 3, with two broiler breeders age (30 and 60 weeks) and three feed deprivation times (0, 24, 48 h post hatching). The broiler breeder age did not affect the chicks lost of weight between hatching and housing, but the feed deprivation time affect this parameter. Chicks from 60-week-old broiler breeders showed greater feed intake 72 hours post hatching. Feed intake and weight gains were influenced by the breeder age 0f 7 and 21 days old, the chick from older breeder siplaying greater feed intake and weight gain. However, at 42 days of age, even if the birds had been subjected to periods of post hatching fasting, they did not display differences on their performance. Chicks from 30-week-old broiler breeders displayed a better feed conversion.Este estudo foi conduzido para avaliar o efeito do jejum entre o nascimento e o alojamento sobre o consumo de ração, ganho de peso, conversão alimentar e viabilidade criatória até 42 dias de idade; perda de peso e consumo de ração no período que suceder ao nascimento, em frangos de corte provenientes de matrizes de diferentes idades. Foram utilizados 480 pintainhos de corte, machos, em um delineamento inteiramente casualizado, em esquema fatorial 2 x 3 com os fatores idades de matriz (30 e 60 semanas) e períodos de jejum (0, 24 e 48 horas pós-eclosão). A idade da matriz não influenciou a perda de peso dos pintainhos entre o nascimento e o alojamento, variável esta afetada apenas pelo período de jejum a qual as aves foram submetidas. Pintainhos oriundos de matizes de 60 semanas de idade consumiram maior quantidade de ração nas 72 horas pós-eclosão. A idade da matriz influenciou também o consumo de ração e o ganho de peso aos 7 e 21dias de idade, sendo que pintainhos oriundos de matrizes mais velhas tiveram maior consumo e ganho de peso. No entanto, aos 42 dias, mesmo que as aves tenham sido submetidas a períodos de jejum pós-natal, não houve diferença no desempenho. Pintainhos oriundos de matrizes de 30 semanas tiveram melhor conversão alimentar nesta idade.

    EFEITO DA IDADE DA MATRIZ NO TEMPO DE ECLOSÃO, TEMPO DE PERMANÊNCIA DO NEONATO NO NASCEDOURO E O PESO DO PINTAINHO

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    Six hundred eggs from 32, 43 and 60 week-old Cobb-500®  broiler breeder were incubated at 37,8°C  and 60% of humidity. It was used a completely randomized design with three treatments (broiler breeder ages) and 200 repetitions (each embryo/chick was considered a repetition). Eggs were weighted at 1st and 19 th days, weight losses during the incubation were estimated, chicks were weighted at birth and when they were removed from hatchery and weight losses during this period were measured. Eggs and chicks from older broiler breeder were heavier. There were no differences in relation to egg weight losses, on chick weight percentages (chick weight/egg weight ratio), of incubation time (h) and on the weight losses during their hatchery remaining. Considering 32, 43 and 60 week-old broiler breeder, respectively, initial egg weight was highly and positively correlated with egg weight at 19 th day of incubation (0.75; 0.86 and 0.79), with birth chick weight (0.57, 0.72, 0.72) and with chick weight at hatchery removing (0.38, 0.41, 0.51); positive correlations (0.61,0.41 and 0.63) were observed between incubation time and chick weight. Negative correlations (-0.79, -0.96 and -0.76) were found between incubation time and chick weight losses during hatchery remaining. In conclusion, broiler breeder age affected egg and chick weight. Eggs from different broiler breeder ages might be incubated during the same period without affecting the quality of newborn in function of the time spends in hatchery.Utilizaram-se 600 ovos embrionados, provenientes de matrizes de 32, 43 e 60 semanas de idade, da linhagem Cobb – 500, incubados a 37,8°C e 60% de umidade. Foram analisados peso do ovo, peso dos ovos aos 19 dias de incubação, tempo de incubação, perda de peso do ovo durante a incubação, peso dos pintainhos no momento do nascimento e na retirada do nascedouro e perda de peso do pintainho no nascedouro. Foi utilizado um delineamento inteiramente ao acaso com 3 tratamentos (idade da matriz) e 200 repetições (cada ovo foi considerado uma repetição). Os resultados foram submetidos à análise de variância e Teste de Tukey (5%). Matrizes mais velhas produziram ovos mais pesados. Não houve diferença na perda de peso de ovos, no percentual de peso dos pintainhos, no tempo de incubação (h) e também na perda de peso do pintainho no nascedouro. Houve uma correlação positiva (0,75; 0,86; 0,79 respectivamente para matrizes de 32, 43 e 60 semanas) entre o peso inicial dos ovos e o peso dos ovos aos 19 dias de incubação, com o peso do pintainho, no momento do nascimento (0,57; 0,72; 0,72) e no momento da retirada do nascedouro (0,38; 0,41; 0,51). Também houve correlação (0,61; 0,41 e 0,63) entre o tempo de incubação e o peso do pintainho e com a perda de peso do pintainho no nascedouro (-0,79; -0,96; -0,76). Conclui-se que a idade da reprodutora afeta o peso do ovo e do pintainho. Ovos de matrizes de diferentes idades necessitam o mesmo tempo para incubação

    AVALIAÇÃO DE DIFERENTES FONTES E NÍVEIS DE SELÊNIO PARA FRANGOS DE CORTE EM DIFERENTES TEMPERATURAS

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    Foram avaliados os parâmetros zootécnicos de frangos de corte alimentados com dietas suplementadas com diferentes fontes e níveis de selênio (Se), criados sob diferentes condições de temperatura. Foram utilizados 720 pintainhos, Cobb-500, em um delineamento inteiramente ao acaso em esquema fatorial 3 x 2 x 2 (3 temperaturas ambiente: termoneutra, fria e quente; 2 níveis de suplementação de Se: nível A e B; e 2 fontes de Se: orgânica e inorgânica), com 4 repetições de 15 aves. Os níveis A e B de Se na ração inicial (1 a 21 dias) e de crescimento (22 a 42 dias) foram 0,15 e 0,30 mg/kg e 0,20 e 0,40 mg/kg, respectivamente. Selenometionina foi usada como fonte de Se orgânico e selenito de sódio, inorgânico. Os frangos criados em condições de estresse por calor apresentaram uma redução no consumo de ração e ganho de peso. Não houve influência da suplementação das diferentes fontes ou níveis de Se no ganho de peso, consumo de ração ou conversão alimentar. Os resultados são indicativos de que a suplementação de Se não melhora o desempenho de frangos de corte criados em condições de temperatura adversa. Evaluation of different sources and selenium levels for broilers at different temperatures Abstract This study evaluated the effect of selenium (Se) diet supplementation on productive parameters of broiler chickens raised under different temperatures, in a complete randomized design with 3 x 2 x 2 factorial schedule (3 environmental temperatures: cold, neutral and hot; 2 levels and two Se sources) with 4 repetitions of 15 birds. The levels of Se in rations for initial and growth phases were: 0.15 and 0.30 mg/kg; and 0.20 and 0.40 mg/kg, respectively. The organic and inorganic sources of selenium were selenomethionine and sodium selenite, respectively. There were a reducing in broiler feed intake and weight gain of the broilers housed in the hot temperature. Selenium levels or sources did not affect the weight gain, feed intake or feed conversion. It was concluded that Se supplementation did no affect the broiler performance, housed under adverse environmental temperature

    SUPLEMENTAÇÃO DIETÉTICA DE SELÊNIO PARA FRANGOS DE CORTE E SEUS EFEITOS SOBRE O EMPENAMENTO

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    Foi avaliado o empenamento de frangos de corte alimentados com dietas suplementadas com diferentes fontes e níveis de selênio (Se), criados sob diferentes condições de temperatura. Foram utilizados 720 pintainhos, Cobb-500, em um delineamento inteiramente ao acaso em esquema fatorial 3 x 2 x 2 (3 temperaturas ambiente: termoneutra, fria e quente; 2 níveis de suplementação de Se: nível A e B; e 2 fontes de Se: orgânica e inorgânica), com 4 repetições de 15 aves. Os níveis A e B de Se na ração inicial (1 a 21 dias) e de crescimento (22 a 42 dias) foram 0,15 e 0,30 mg/kg e 0,20 e 0,40 mg/kg, respectivamente, sendo Selenito de sódio a fonte inorgânica e selenometionina a forma de suplementação orgânica. Os frangos criados no calor apresentaram menor cobertura e crescimento de penas. Aos 21 dias de idade o Se orgânico induziu a um mais rápido empenamento nas regiões pterígeas avaliadas, independente da variação dos níveis de Se estudados. Entretanto, a avaliação feita aos 42 dias mostrou que a suplementação de Se, nas suas diferentes formas e níveis, não interferiu no empenamento nesta idade. Os resultados são indicativos de que a suplementação de Se na sua forma orgânica parece ser a melhor maneira de se obter um bom empenamento dos frangos de corte em uma fase crítica para a sua homeostase térmica, isto é, até os 21 dias de idade. Selenium dietary supplementation of broilers and its effects on feathering Abstract This study evaluated the feathering of broiler fed supplemented diet with different selenium (Se) sources and levels, raised under different environmental temperatures. Seven hundred twenty broiler chicks were raised in a complete randomized design with 3 x 2 x 2 factorial schedule (3 environmental temperatures: cold, neutral and hot; two levels and two Se sources) with 4 repetitions of 15 birds. The levels of Se in rations for initial and growth phases were: 0.15 and 0.30 mg/kg; and 0.20 and 0.40 mg/kg, respectively. The organic and inorganic sources of selenium were selenomethionine and sodium selenite, respectively. There was a feathering reducing of the broilers housed in the hot temperature. At 21 days of birth organic selenium induces a fast feathering growth on the pteriloses evaluated regions. However, at 42 days, different selenium levels or sources did not affect the broiler feathering. These data show that organic selenium supplementation is the better way to get a good broiler feathering on critical phase of thermal homeostasis, until 21 days of birth

    Holographic Dark Energy and the Universe Expansion Acceleration

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    By incorporating the holographic principle in a time-depending Lambda-term cosmology, new physical bounds on the arbitrary parameters of the model can be obtained. Considering then the dark energy as a purely geometric entity, for which no equation of state has to be introduced, it is shown that the resulting range of allowed values for the parameters may explain both the coincidence problem and the universe accelerated expansion, without resorting to any kind of additional structures.Comment: Ordinary LaTex, 8 page

    Construction of effective disposable biosensors for point of care testing of nitrite

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    © 2015. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/"In this paper we aim to demonstrate, as a proof-of-concept, the feasibility of the mass production of effective point of care tests for nitrite quantification in environmental, food and clinical samples. Following our previous work on the development of third generation electrochemical biosensors based on the ammonia forming nitrite reductase (ccNiR), herein we reduced the size of the electrodes’ system to a miniaturized format, solved the problem of oxygen interference and performed simple quantification assays in real samples. In particular, carbon paste screen printed electrodes (SPE) were coated with a ccNiR/carbon ink composite homogenized in organic solvents and cured at low temperatures. The biocompatibility of these chemical and thermal treatments was evaluated by cyclic voltammetry showing that the catalytic performance was higher with the combination acetone and a 40 °C curing temperature. The successful incorporation of the protein in the carbon ink/solvent composite, while remaining catalytically competent, attests for ccNiR’s robustness and suitability for application in screen printed based biosensors. Because the direct electrochemical reduction of molecular oxygen occurs when electroanalytical measurements are performed at the negative potentials required to activate ccNiR (ca. -0.4 V vs Ag/AgCl), an oxygen scavenging system based on the coupling of glucose oxidase and catalase activities was successfully used. This enabled the quantification of nitrite in different samples (milk, water, plasma and urine) in a straightforward way and with small error (1 – 6%). The sensitivity of the biosensor towards nitrite reduction under optimized conditions was 0.55 A M-1 cm-2 with a linear response range 0.7 – 370 μM.
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