Caracterização do efetivo caprino da raça Boer em Portugal

A raça caprina Boer, originária da Africa do Sul, é considerada uma das raças mais importantes para a produção de carne, apresentando uma excelente capacidade de adaptação, sendo por isso explorada, com sucesso, em várias zonas do globo, com condições meteorológicas muito variadas. Atualmente, a exploração de caprinos desta raça em Portugal ainda tem uma expressão bastante diminuta, tendo sido concluída a criação do Livro Genealógico (LG) da raça Boer em novembro de 2015, gerido pela APCRB – Associação Portuguesa de Caprinicultores da Raça Boer. Pretendeu-se com este estudo contribuir para a caracterização do efetivo caprino Boer existente em Portugal. O trabalho baseou-se nos dados obtidos em visitas realizadas às explorações, no processo de registo dos animais no LG da raça. Atualmente, em Portugal, existem nove criadores, mas apenas oito com animais inscritos no LG, com um efetivo total de 142 animais, 112 fêmeas e 30 machos. Os animais são nascidos em Portugal (48,6%), e importados, principalmente da Alemanha (36,6%), mas também da Holanda (12,7%) e Espanha (2,1%). As explorações encontram-se distribuídas pelos concelhos de Alandroal, Benavente, Vidigueira, Campo-Maior, Coruche, Évora, Portalegre, Porto de Mós e Vila Nova de Foz Côa. Os criadores, na sua maioria, exploram os animais em sistema semi-intensivo, com base no pastoreio direto e suplementação, com feno e alimento composto comercial. Apenas um criador explora os animais em sistema extensivo. Regra geral, não existem épocas de cobrição definidas. Os machos são mantidos junto das fêmeas e a beneficiação realiza-se por cobrição natural. Excecionalmente, no ano de 2016, dois criadores recorreram à inseminação artificial, por laparoscopia, com sémen importado da Austrália. A dimensão dos efetivos por exploração é diversa, variando entre quatro e trinta animais, com um valor médio de dezoito animais. O efetivo nacional é relativamente jovem, predominando animais com idades entre um e três anos, representando 85% do efetivo. O número de nascimentos aumentou entre 2007 e 2013, ano em que se registou o valor mais elevado (42), tendo este vindo a decrescer posteriormente. A inexistência de épocas de cobrição definidas reflecte-se numa distribuição dos nascimentos ao longo de todo o ano. A pontuação obtida na classificação morfológica dos animais, efetuada até ao momento, permitiu que a sua totalidade fosse inscrita no LG. Apesar de uma expressão ainda diminuta do efetivo Boer em Portugal, a expansão desta raça afigura-se interessante, dadas as excelentes características destes animais para a produção de carne.info:eu-repo/semantics/publishedVersio

Comunidades nectónicas en substratos fangosos del estuario del Tajo (Portugal): distribucción y pautas alimenticias

Mudflats are an important component of estuaries, where they may occupy large areas and provide feeding and nursery grounds for many fish and bird species, as in the Tagus estuary. However, knowledge on their role and functioning is still expanding. Spatial and temporal dynamics of nekton assemblages in a mudflat of the Tagus estuary were evaluated to determine their role in the estuarine functioning. Feeding activity and daily rations of the most important nekton species are also analyzed. Two intertidal mudflat areas (upper and lower) were sampled, as well as the adjoining subtidal area. Sampling was conducted every two months, during a yearly cycle. A 24 h sampling cycle was conducted to investigate daily feeding patterns and determine daily rations. Crangon crangon, Carcinus maenas, Palaemon longirostris, Palaemon serratus and Pomatoschistus microps dominated the nekton community. A marked seasonal pattern was noticed with the highest densities recorded in spring and summer, corresponding to recruitment episodes of these species. Highest biomass values were recorded in the subtidal zone, while the highest densities were recorded in the intertidal zone. The mudflats seem to play an important role in the dynamics of the Tagus estuary, acting as a feeding and nursery areas for several nektonic species.Los substratos fangosos son componentes importantes de los estuarios, donde pueden ocupar amplias zonas y proporcionar alimento a las áreas de nursery de muchos peces y aves, como en el estuario de Tagus. Sin embargo, el conocimiento sobre su papel y funcionamiento es aún escaso. Se estudiaron la dinámica espacial y temporal de las comunidades bentónicas en una zona fangosa del estuario de Tagus, determinando su papel en el funcionamiento del estuario. Asimismo, se analizó la actividad alimenticia y las raciones diarias de las especies principales del nekton. Se muestrearon dos áreas fangosas intermareales (superior e inferior), así como las zonas submareales adyacentes. Los muestreos se realizaron cada dos meses durante un año. Se realizó un ciclo de 24 h para investigar las pautas alimenticias y determinar la ración diaria. Crangon crangon, Carcinus maenas, Palaemon longirostris, Palaemon serratus y Pomatoschistus microps dominan la comunidad nectónica. Se observa una pauta estacional clara, con las densidades más altas en primavera y verano, que corresponden a los episodios de reclutamiento de las especies mencionadas. Las biomasas más elevadas se obtuvieron en la zona submareal, mientras las densidades mayores se midieron en el intermareal. Los fondos fangosos del estuario de Tagus parecen jugar un papel importante en su dinámica, actuado como áreas de alimento y nursery de diversas especies nectónicas

Infection characteristics of a trematode in an estuarine isopod: influence of substratum

The estuarine isopod Cyathura carinata is a second intermediate host to microphallid trematodes, which use mud snails Hydrobia spp. and shorebirds as respectively first intermediate and final hosts. To identify processes responsible for infection patterns observed in C. carinata, a short-term microcosm experiment was conducted with both macroinvertebrates and one of their common parasites – Maritrema subdolum. Fine sand collected from two different shallow water sites was used to test if sediment type could affect infection rates. After 7 days at 25 °C, C. carinata from the substratum with the highest proportion of particles µm were more surface active and obtained significantly more M. subdolum individuals than isopods from the other sediment type. No parasite-induced effects on the hosts were found during this short-term experiment. The distribution pattern of microphallid cysts and mesocercariae inside the isopods revealed that M. subdolum cercariae primarily penetrated through the pleopods and afterwards located themselves in the middle-posterior region of the host’s body. Even if it was not possible to identify the factor responsible for the observed infection patterns (cercariae production and/or host behaviour), the results of this experiment indicate that small-scale factors, such as differences in substratum and associated features, may have considerable impact on infections of host populations

Contribution of primary producers to mercury trophic transfer in estuarine ecosystems: Possible effects of eutrophication

http://www.sciencedirect.com/science/article/B6V6N-4V2X6WR-2/2/583d9d39ab618163fcc19f359dde856

Modeling ultra-high frequency radiation emission in PIC codes

From the mysterious?ray bursts, which can be studied through the spatiotemporal structure of the radiation we receive, to the creation of sources of x-rays capable of probing nanoscale structures, radiation emission by relativistic charges is a key research field in plasma physics.The processes behind radiation emission in plasmas result from strongly non-linear many body interactions which involve relativistic effects, so they are best modeled through Particle-In-Cell (PIC) simulations. However, capturing this radiation directly in PIC simulations is very challenging due to the large disparity between the temporal and spatial scales associated with such phenomena. Current algorithms only describe radiation processes in the Fourier space (e.g.JRAD [1]), missing the spatiotemporal features of the emitted radiation, which is crucial to many fields, such as super-resolution microscopy [2] and astrophysics [3].info:eu-repo/semantics/publishedVersio

RaDiO: An efficient spatiotemporal radiation diagnostic for particle-in-cell codes

This work describes a novel radiation algorithm designed to capture the three-dimensional, space-time resolved electromagnetic field structure emitted by large ensembles of charged particles. The algorithm retains the full set of degrees of freedom that characterize electromagnetic waves by employing the Liénard-Wiechert fields to retrieve radiation emission. Emitted electric and magnetic fields are deposited in a virtual detector using a temporal interpolation scheme. This feature is essential to accurately predict field amplitudes and preserve the continuous character of radiation emission, even though particle dynamics is known only in a discrete set of temporal steps. Our algorithm retains and accurately captures, by design, full spatial and temporal coherence effects. We demonstrate that our numerical approach recovers well known theoretical radiated spectra in standard scenarios of radiation emission. We show that the algorithm is computationally efficient by computing the full spatiotemporal radiation features of High Harmonic Generation through a plasma mirror in a Particle-In-Cell (PIC) simulation.info:eu-repo/semantics/publishedVersio

Estuarine production of resident and nursery fish species: Conditioning by drought events?

The production of resident (Pomatoschistus minutus and Pomatoschistus microps) and marine juvenile fish species using the Mondego estuary (central Portugal) as nursery grounds (Dicentrarchus labrax, Platichthys flesus, Solea solea), was assessed in order to: (1) understand the potential of the estuary for fish production; (2) know the production of nursery fish species likely to be exported to the coastal stocks; and (3) how anthropogenic and natural stress could influence the estimated production. Sampling occurred from June 2003 to May 2006 and together the 5 species in study comprised around 70% of the whole fish community numbers and biomass. Increasing drought conditions were observed, starting with a normal hydrological year in 2003 until attaining a severe drought in 2005, which resulted in low river discharges (1/3 of the mean river discharges in 2003). Additionally, high water temperatures were observed in 2003 and 2005 (24 and 26 °C, night temperatures). The secondary production was estimated using the increment summation method, after recognition of the cohorts. Production was in general lower in the Mondego estuary when compared to other systems, which was associated to the estuary's small area (only 3.4 km2, less than 1/4 of area compared to other studied systems). Dicentrarchus labrax was among the most productive species. Production decreased in the drought year for all species, especially evident for D. labrax, P. minutus and P. flesus. No direct effects could be attributable to the salinity and temperature variations and to the low freshwater discharges (resulting from the drought and high temperatures), yet these were pointed as probable major reasons for the decreased production. A significant reduction (15-45% reduction in the estuarine production) was also concluded for the potential production to be exported for coastal areas by the nursery species in the drought conditions.http://www.sciencedirect.com/science/article/B6WDV-4R9GGXS-2/1/663d5981f8928a75fea6999bf328f16

Characterization of MHC class I in a long distance migratory wader, the Icelandic black-tailed godwit

The major histocompatibility complex (MHC) encodes proteins that are central for antigen presentation and pathogen elimination. MHC class I (MHC-I) genes have attracted a great deal of interest among researchers in ecology and evolution and have been partly characterized in a wide range of bird species. So far, the main focus has been on species within the bird orders Galliformes and Passeriformes, while Charadriiformes remain vastly underrepresented with only two species studied to date. These two Charadriiformes species exhibit striking differences in MHC-I characteristics and MHC-I diversity. We therefore set out to study a third species within Charadriiformes, the Icelandic subspecies of black-tailed godwits (Limosa limosa islandica). This subspecies is normally confined to parasite-poor environments, and we hence expected low MHC diversity. MHC-I was partially characterized first using Sanger sequencing and then using high-throughput sequencing (MiSeq) in 84 individuals. We verified 47 nucleotide alleles in open reading frame with classical MHC-I characteristics, and each individual godwit had two to seven putatively classical MHC alleles. However, in contrast to previous MHC-I data within Charadriiformes, we did not find any evidence of alleles with low sequence diversity, believed to represent non-classical MHC genes. The diversity and divergence of the godwits MHC-I genes to a large extent fell between the previous estimates within Charadriiformes. However, the MHC genes of the migratory godwits had few sites subject to positive selection, and one possible explanation could be a low exposure to pathogens.Financial support to SP was provided by PhD grant SFRH/BD/84629/2012 from Fundação para a Ciência e a Tecnologia (FCT); to JAA by FCT grant SFRH/BPD/91527/2012. This study benefited from funding by RANNIS - Icelandic Research Council (130412-051), the strategic project (UID/MAR/04292/2013) granted to MARE and H. Westerdahl financed through Swedish Research Council (621-2011-3674 and 2015-05149) and provided the laboratory facilities for molecular analysis.Peer Reviewe

Forbidden induced subgraph characterization of circle graphs within split graphs

A graph is circle if its vertices are in correspondence with a family of chords in a circle in such a way that every two distinct vertices are adjacent if and only if the corresponding chords have nonempty intersection. Even though there are diverse characterizations of circle graphs, a structural characterization by minimal forbidden induced subgraphs for the entire class of circle graphs is not known, not even restricted to split graphs (which are the graphs whose vertex set can be partitioned into a clique and a stable set). In this work, we give a characterization by minimal forbidden induced subgraphs of circle graphs, restricted to split graphs.Comment: 59 pages, 15 figure