Recursos de colección

Repositorio da Universidade dos Açores (9.269 recursos)

O Repositório Institucional da Universidade dos Açores desenvolvido no âmbito do projecto RCAAP.

DCA - Artigos em Revistas Internacionais / Articles in International Journals

Mostrando recursos 1 - 20 de 187

  1. Invasions changing marine biodiversity. Comment on J.M. Pandolfi & C.E. Lovelock Perspective in Ecology "Novelty Trumps Loss in Global Biodiversity" (18 April, 344, 266).

    Barreiros, João P.
    Although global biodiversity is declining, local ecosystems are not systematically losing diversity, but rather experiencing rapid turnover in species.

  2. Comment on R. Woodroffe et al. Perspective in Ecology "To Fence or Not to Fence" (4 April 2014, Science, 344: 46-48)

    Barreiros, João P.
    Fences must be used with care in biodiversity conservation to avoid unintended consequences.

  3. Partitioning taxon, phylogenetic and functional beta diversity into replacement and richness difference components

    Cardoso, Pedro; Rigal, François; Carvalho, José C.; Fortelius, Mikael; Borges, Paulo A. V.; Podani, János; Schmera, Dénes
    To propose a unified framework for quantifying taxon (Tβ), phylogenetic (Pβ) and functional (Fβ) beta diversity via pairwise comparisons of communities, which allows these types of beta diversity to be partitioned into ecologically meaningful additive components.

  4. First record of the dusky grouper Epinephelus marginatus (Actinopterygii: Epinephelidae) undergoing sexual transition in the South Western Atlantic, Brazil

    Condini, Mario V.; Seyboth, Elisa; Vieira, João P.; Varela-Jr., Antônio S.; Barreiros, João P.; Favaro, Luís F.; Garcia, Alexandre M.
    The dusky grouper Epinephelus marginatus historically exploited by fisheries is a marine species showing slow growth, late maturation and protogynous hermaphroditism. Currently, it is considered as endangered by the IUCN. Therefore, it is essential to increase the knowledge about its biology and ecology to help conservation of this species. The present study reports the first record of a dusky grouper individual undergoing sexual transition, from female to male, in the Atlantic Ocean based on histological analyses of gonads. The specimen with total length: 770 mm; total weight: 8.1 kg and age: 21 years was captured in a rocky bottom along...

  5. Spatial distribution of Madeira Island Laurisilva endemic spiders (Arachnida: Araneae)

    Crespo, Luís C.; Boieiro, Mário; Cardoso, Pedro; Aguiar, Carlos A. S.; Amorim, Isabel R.; Barrinha, Carla; Borges, Paulo A. V.; Menezes, Dilia; Pereira, Fernando E. A.; Rego, Carla; Ribeiro, Sérvio P.; Silva, Israel F.; Serrano, Artur R. M.
    Copyright © Crespo L et al.. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

  6. Comparison of Bacterial Diversity in Azorean and Hawai'ian Lava Cave Microbial Mats

    Hathaway, Jennifer J. Marshall; Garcia, Matthew G.; Balasch, Monica Moya; Spilde, Michael N.; Stone, Fred D.; Dapkevicius, Maria De Lurdes N. E.; Amorim, Isabel R.; Gabriel, Rosalina; Borges, Paulo A. V.; Northup, Diana E.
    Worldwide, lava caves host colorful microbial mats. However, little is known about the diversity of these microorganisms, or what role they may play in the subsurface ecosystem. White and yellow microbial mats were collected from four lava caves each on the Azorean island of Terceira and the Big Island of Hawai’i, to compare the bacterial diversity found in lava caves from two widely separated archipelagos in two different oceans at different latitudes. Scanning electron microscopy of mat samples showed striking similarities between Terceira and Hawai’ian microbial morphologies. 16S rRNA gene clone libraries were constructed to determine the diversity within these...

  7. First record of Alosa fallax (Lacépède, 1803) (Teleostei: Clupeiformes:Clupeidae) in the Azores Archipelago, Portugal (NE Atlantic)

    Barreiros, João P.; Vieira, Rui P.; Machado, Leonardo F.
    This note reports the first record of Alosa fallax (Lacépède, 1803) in the Azores Archipelago (NE Atlantic, Portugal). Being an anadromous species, this occurrence is quite unexpected since there are no suitable breeding habitats for this species in these volcanic islands, isolated and river less. Although A. fallax is known to migrate offshore, it has never been previously reported in oceanic environments. We discuss this occurrence and theorize on the possibility of the species’ being found in Madeira, another Macaronesian Archipelago, albeit much older and closer to European coasts and thus more suitable to be crossed by A. fallax during...

  8. Prorural: Program assessment in an involved actor's perspective

    Silva, Emiliana; Mendes, Armando B.
    PRORURAL- Azores Rural Development Plan - for 2007 to 2013, is the European Union rural development policy adjusted to the Azores Region and it is supported by European Agricultural Fund for Rural Development. The PRORURAL was approved by Commission Decision C (2007) 6162, on the 4th of December 2007. The PRORURAL has four center lines: 1) improving competitiveness of the agricultural and forestry sectors; 2) improvement of the environment and rural landscape; 3) quality of life in rural areas and diversification of economy; and 4) operation of LAGs, Acquisition of skills and entertainment in rural areas. The financial implementation rate...

  9. Comparison of three sources of inocula for predicting apparent digestibility of ruminant feedstuffs

    Borba, Alfredo Emílio Silveira de; Correia, Pedro J. A.; Fernandes, Jorge M. M.; Borba, Anabela F. R. S.
    In the present study, gas production of three sources of inocula rumen liquor from fistulated sheep, rumen liquor from slaughtered cattle, and a suspension of sheep faeces, were evaluated to predict the apparent digestibility of ruminant feedstuffs. The highest gas production was obtained with rumen liquor from slaughtered cattle, and the lowest (P < 0.05) with the suspension of sheep faeces. The relationship between gas production and in vivo apparent digestibility was determined on 24 samples of graminaceous (oats (Avena sativa L.), Italian ryegrass (Lolium multiflorum L.), perennial ryegrass (Lolium perenne L.) and maize (Zea mays L.)) at three stages...

  10. Characterization of in situ dry matter and protein degradation of green and ensiled oats forages at three stages of growth

    Borba, Alfredo Emílio Silveira de; Ribeiro, João Ramalho
    Special Issue: IVth International Symposium on the Nutrition of Herbivores, Clermont-Ferrand (France), September 11-15, 1995.

  11. A comparison of alternative sources of inocula in an in vitro digestibility technique

    Borba, Alfredo Emílio Silveira de; Ribeiro, João Ramalho
    In this paper we make the comparison between sources of inocula for an in vitro digestibility method based on that of Tilley and Terry (1963) as modified by Alexander and McGowan (1966). The best results for the prediction of the in vivo digestibility were obtained using the traditional method of rumen liquor from fistulated sheep. However, with the two alternative methods, one using rumen liquor from slaughtered cattle, and another, a sheep faeces suspension as inocula sources, we obtained results significantly correlated with in vivo digestibility at the 5% level, although with lower correlation coefficients. The method that uses rumen...

  12. The feeding value of green and ensiled São Jorge natural pasture

    Borba, Alfredo Emílio Silveira de; Vouzela, Carlos Fernando Mimoso; Borba, Anabela F. R. S.
    This paper presents the results of a study of the feeding value of São Jorge pastures in green and in big bale silage.

  13. Effect of diet on the fatty acid pattern of milk from dairy cows

    Rego, Oldemiro Aguiar do; Portugal, Paula V.; Sousa, Marisa B.; Rosa, Henrique José Duarte; Vouzela, Carlos Fernando Mimoso; Borba, Alfredo Emílio Silveira de; Bessa, Rui José B.
    Twelve dairy cows 130 days in milk were sorted by milk production and body weight and assigned to three feeding regimens in a 3 × 3 Latin-square design, in order to study the effects of diet on milk fatty acid (FA) composition. The cows were fed a total mixed ration (TMR) consisting of corn silage (60%) and concentrate (40%) on dry matter basis, or grazed pasture, without (P) or with 5 kg•d-1 concentrate as a supplement (SP). Supplemented grazing dairy cows produced significantly more milk than the cows on the TMR and P diets (P < 0.05). The supplementation of...

  14. The effects of supplementation with sunflower and soybean oils on the fatty acid profile of milk fat from grazing dairy cows

    Rego, Oldemiro Aguiar do; Rosa, Henrique José Duarte; Portugal, Paula V.; Franco, Tiago; Vouzela, Carlos Fernando Mimoso; Borba, Alfredo Emílio Silveira de; Bessa, Rui José B.
    The objective of this study was to observe the effect of supplementation with vegetable oils (VO) on the fatty acid profiles and conjugated linoleic acid (CLA) content of milk fat. Twelve dairy cows in mid lactation fed on pasture were blocked by body weight, milk production and days in lactation and randomly allocated from blocks to 3 treatments repeated in a Latin square design with periods of 28 day duration. The treatments were as follows: cows on pasture supplemented with 5 kg concentrate per head per day (C), supplemented with 4.5 kg concentrate + 0.5 kg sunflower oil per head...

  15. Influence of dietary fish oil on conjugated linoleic acid, omega-3 and other fatty acids in milk fat from grazing dairy cows

    Rego, Oldemiro Aguiar do; Rosa, Henrique José Duarte; Portugal, Paula V.; Cordeiro, R.; Borba, Alfredo Emílio Silveira de; Vouzela, Carlos Fernando Mimoso; Bessa, Rui José B.
    The main objective of this study was to evaluate the effect of supplementation with fish oil on fatty acid (FA) composition of milk fat from grazing dairy cows with particular emphasis on omega-3 and conjugated linoleic acid. Twelve dairy cows in mid-lactation were blocked by live weight, days in lactation and milk production and randomly assigned to the experimental groups corresponding to 3 different feeding regimens which were applied 3 times with 28-day duration according to a Latin square design. Cows were stocked at 2.5 heads per hectare and supplemented with 4 kg concentrate/cow/day (C), concentrate mixed with 160 g...

  16. Effects of grass silage and soybean meal supplementation on milk production and milk fatty acid profiles of grazing dairy cows

    Rego, Oldemiro Aguiar do; Regalo, S. M. M.; Rosa, Henrique José Duarte; Alves, Susana Paula A.; Borba, Alfredo Emílio Silveira de; Bessa, Rui José B.; Cabrita, Ana R. J.; Fonseca, A. J. M.
    The effects of supplementation with grass silage and replacement of some corn in the concentrate with soybean meal (SBM) on milk production, and milk fatty acid (FA) profiles were evaluated in a replicated 4 × 4 Latin square study using 16 dairy cows grazing pasture composed of ryegrass, Kentucky bluegrass, and white clover. Each experimental period lasted for 3 wk. The 4 dietary treatments were PC, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn-based concentrate mixture (96% corn; C); PCSB, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn- and SBM-based...

  17. Effects of Plasma Urea Nitrogen Levels on the Bovine Oocyte Ability to Develop After In vitro Fertilization

    Santos, P.; Marques, A.; Antunes, G.; Chaveiro, António E.; Andrade, M.; Borba, Alfredo Emílio Silveira de; Silva, Joaquim Fernando Moreira da
    The overall aim of the present study was to evaluate in vitro development ability of oocytes recovered from 56 Holstein Frisian heifers with low [group 1 (G1): <13 mg /dl], moderate [group 2 (G2): 13–16 mg /dl] and high [group 3 (G3): >16 mg /dl] plasma urea nitrogen (PUN) concentrations, to determine whether PUN concentrations affect the competence of oocytes to progress to blastocysts after in vitro fertilization. In vitro oocyte and embryo development was assessed by blastocyst rates, embryo total cell numbers and apoptosis. Blood samples for the determination of PUN were collected 24 h prior to collection of the ovaries at...

  18. Effects of Condensed Tannins from Quebracho Extract on the Kinetic of in vitro Gas Production on Trifolium repens, Lotus corniculatus and Lolium perenne

    Vieira, Sandrine C.; Borba, Alfredo Emílio Silveira de
    The aim of this work was to study the effect of condensed tannins (CT) on the kinetic of gas production in vitro, on the three main species of Azorean pasture: Trifolium repens, Lotus corniculatus and Lolium perenne, using Quebracho extract as the source of CT, and also to calculate total tannins and condensed tannins on the species studied. Lotus corniculatus, Lolium perenne and Trifolium repens were tested in vitro with the inclusion of Quebracho extract in doses of 0%, 2.5% and 5% DM. The total content in tannins was determined in the 3 species. We have found, in comparison with...

  19. Association between Plasma and Milk Urea on the Insemination Day and Pregnancy Rate in Early Lactation Dairy Cows

    Chaveiro, António E.; Andrade, M.; Borba, Alfredo Emílio Silveira de; Silva, Joaquim Fernando Moreira da
    Lactatingdairy cows (n=177) feed with grass and corn silage ad libitum kept in pasture, were randomly assigned to evaluate how urea nitrogen in plasma and milk can be related to their pregnancy rate. Blood and milk samples were collected on the artificial insemination (AI) day to evaluate plasma urea nitrogen (PUN) and milk urea nitrogen (MUN) as well as progesterone levels, excluding cows with progesterone higher than 0.5 ng/ml. Cows were considered pregnant if six weeks after artificial insemination, they did not return to estrus.Concentrations of PUN or MUN greater than the average (16 mg/dl) were associated with decreased pregnancy...

  20. Productive and reproductive performance of Romney Marsh and Merino Branco sheep in the Azores under different feeding regimens

    Rosa, Henrique José Duarte; Ventura, P. F. M.; Sousa, J. T.; Moreira, D.; Borba, Alfredo Emílio Silveira de; Rego, Oldemiro Aguiar do
    The objective of this study was to compare the productive and reproductive performances of Romney Marsh (RM) and Merino Branco (MB) ewes in the Azores. In a preliminary trial, fertility, prolificacy and fecundity of 25 RM and 27 MB ewes, mortality rate of lambs born and growth rate of lambs (14 RM and 20 MB) from birth to weaning at 24 kg live weight were determined. In a second trial following weaning, the same group of lambs were raised on pasture and supplemented either with concentrate or maize silage until slaughter (101 days later), and growth rate, carcass and meat...

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