Browsing by Issue Date, starting with "2012-01"
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- A meta-analysis of seaweed impacts on seagrasses: generalities and knowledge gapsPublication . Thomsen, Mads S.; Wernberg, Thomas; Engelen, Aschwin; Tuya, Fernando; Vanderklift, Mat A.; Holmer, Marianne; McGlathery, Karen J.; Arenas, Francisco; Kotta, Jonne; Sillimann, Brian R.Seagrasses are important habitat-formers and ecosystem engineers that are under threat from bloom-forming seaweeds. These seaweeds have been suggested to outcompete the seagrasses, particularly when facilitated by eutrophication, causing regime shifts where green meadows and clear waters are replaced with unstable sediments, turbid waters, hypoxia, and poor habitat conditions for fishes and invertebrates. Understanding the situations under which seaweeds impact seagrasses on local patch scales can help proactive management and prevent losses at greater scales. Here, we provide a quantitative review of available published manipulative experiments (all conducted at the patch-scale), to test which attributes of seaweeds and seagrasses (e.g., their abundances, sizes, morphology, taxonomy, attachment type, or origin) influence impacts. Weighted and unweighted meta-analyses (Hedges d metric) of 59 experiments showed generally high variability in attribute-impact relationships. Our main significant findings were that (a) abundant seaweeds had stronger negative impacts on seagrasses than sparse seaweeds, (b) unattached and epiphytic seaweeds had stronger impacts than 'rooted' seaweeds, and (c) small seagrass species were more susceptible than larger species. Findings (a) and (c) were rather intuitive. It was more surprising that 'rooted' seaweeds had comparatively small impacts, particularly given that this category included the infamous invasive Caulerpa species. This result may reflect that seaweed biomass and/or shading and metabolic by-products like anoxia and sulphides could be lower for rooted seaweeds. In conclusion, our results represent simple and robust first-order generalities about seaweed impacts on seagrasses. This review also documented a limited number of primary studies. We therefore identified major knowledge gaps that need to be addressed before general predictive models on seaweed-seagrass interactions can be build, in order to effectively protect seagrass habitats from detrimental competition from seaweeds.
- The coastal syndromes and hotspots on the coastPublication . Newton, Alice; Carruthers, Tim; Icely, JohnHuman intervention has resulted in a number of global and riverriver-mouth syndromes that are mirrored by coastal syndromes caused by erosion, subsidence, salinization of aquifers, urbanization, eutrophication, invasive species and over exploitation of natural resources. These problems are now global, with few coastal zones remaining unaffected and pristine. However, the problems are particularly severe at “hotspots” in the coastal zone. These include river-mouth systems where fluxes of water, sediment, fertilizers and contaminants are focused; urbanized coasts and megacities where vulnerable populations are concentrated; Arctic coasts where the effects of climate change are accelerating a fundamental state change; and, at low lying coasts that are at risk of flooding, storm surges, sea-level rise and subsidence such as Micronesian island states where managed realignment and setback is not an option. A range of societal responses and appropriate governance frameworks will be necessary to treat the coastal syndromes.
- Northern refugia and recent expansion in the North Sea: the case of the wrasse Symphodus melops (Linnaeus, 1758)Publication . Robalo, Joana I.; Castilho, Rita; Francisco, Sara M.; Almada, Frederico; Knutsen, Halvor; Jorde, Per E.; Pereira, Ana M.; Almada, Vitor C.Pleistocene climate changes have imposed extreme conditions to intertidal rocky marine communities, forcing many species to significant range shifts in their geographical distributions. Phylogeographic analyses based on both mitochondrial and nuclear genetic markers provide a useful approach to unravel phylogeographic patterns and processes of species after this time period, to gain general knowledge of how climatic changes affect shifts in species distributions. We analyzed these patterns on the corkwing wrasse (Symphodus melops, Labridae), a rocky shore species inhabiting North Sea waters and temperate northeastern Atlantic Ocean from Norway to Morocco including the Azores, using a fragment of the mitochondrial control region and the first intron of the nuclear S7 ribosomal protein gene. We found that S. melops shows a clear differentiation between the Atlantic and the Scandinavian populations and a sharp contrast in the genetic diversity, high in the south and low in the north. Within each of these main geographic areas there is little or no genetic differentiation. The species may have persisted throughout the last glacial maximum in the southern areas as paleotemperatures were not lower than they are today in North Scandinavia. The North Sea recolonization most likely took place during the current interglacial and is dominated by a haplotype absent from the south of the study area, but present in Plymouth and Belfast. The possibility of a glacial refugium in or near the English Channel is discussed.
- Subsidios breves para o debate de princípios e valores na formação politica do(a) educador(a) socialPublication . Barros, RosannaO livro que agora sai a lume é o último de uma trilogia recente da autora - trilogia esta que é constituída de textos relativamente longos e com conteúdos distintos, mas abordando sempre temas e objectos de pesquisa empírica e de reflexão teórico-conceptual referenciáveis ao campo da educação e formação de adultos, e respectivas políticas públicas. Este livro, tento uma intencionalidade (política e pedagógica) relativamente diferente, não deixa de se inscrever nesse mesmo campo, sobretudo se considerarmos os estudantes do ensino superior como adultos em formação, e assumirmos que a formação, convocando embora conteúdos e metodologias que pressupõem necessariamente um rigoroso domínio cientifico, não é, nem pode ser, uma formação acrítica e despolitizada, isto é, não pode ser neutra ou asséptica face à pluralidade de valores e visões do mundo com os quais nos confrontamos quotidianamente, quer a nível individual, quer colectivo.
- Sentidos da extravagância dos contos em Le Sopha e Ah quel Conte! de Claude CrébillonPublication . Carvalho, Ana Alexandra Mendonça Seabra da Silva Andrade deEm Le Sopha e Ah quel Conte!, Crébillon recorre à extravagância para problematizar o exotismo maravilhoso na literatura coeva e propor uma reflexão sobre questões de natureza moral e política. Metempsicose, metamorfoses, encantamentos, extraídos do vasto fundo de motivos do conto maravilhoso, alimentam a imaginação criadora do autor, que, fiel à ironia da sua poética do jogo, se serve da bizarria feérica e orientalizante para criticar os costumes, à maneira da comédia molieresca. O desvelar decente das máscaras sociais insere-se numa busca do verdadeiro amor, o qual não corresponde à ideologia preciosa, mas deve integrar harmoniosamente “le coeur, l’esprit et les sens”, algures entre o amor puro inacessível e o puro desejo mascarado de falso sentimento. Estes contos galantes orientais são, pois, obras ao serviço de uma visão irónica e céptica da sociedade.
- Mob1: defining cell polarity for proper cell divisionPublication . Tavares, Alexandra; Gonçalves, João; Florindo, Claudia; Tavares, Alvaro A.; Soares, HelenaMob1 is a component of both the mitotic exit network and Hippo pathway, being required for cytokinesis, control of cell proliferation and apoptosis. Cell division accuracy is crucial in maintaining cell ploidy and genomic stability and relies on the correct establishment of the cell division axis, which is under the control of the cell's environment and its intrinsic polarity. The ciliate Tetrahymena thermophila possesses a permanent anterior posterior axis, left right asymmetry and divides symmetrically. These unique features of Tetrahymena prompted us to investigate the role of Tetrahymena Mob1. Unexpectedly, we found that Mob1 accumulated in basal bodies at the posterior pole of the cell, and is the first molecular polarity marker so far described in Tetrahymena. In addition, Mob1 depletion caused the abnormal establishment of the cell division plane, providing clear evidence that Mob1 is important for its definition. Furthermore, cytokinesis was arrested and ciliogenesis delayed in Tetrahymena cells depleted of Mob1. This is the first evidence for an involvement of Mob1 in cilia biology. In conclusion, we show that Mob1 is an important cell polarity marker that is crucial for correct division plane placement, for cytokinesis completion and for normal cilia growth rates.
- The effects of inbreeding, genetic dissimilarity and phenotype on male reproductive success in a dioecious plantPublication . Austerlitz, Frederic; Gleiser, Gabriela; Teixeira, Sara; Bernasconi, GiorginaPollen fate can strongly affect the genetic structure of populations with restricted gene flow and significant inbreeding risk. We established an experimental population of inbred and outbred Silene latifolia plants to evaluate the effects of (i) inbreeding depression, (ii) phenotypic variation and (iii) relatedness between mates on male fitness under natural pollination. Paternity analysis revealed that outbred males sired significantly more offspring than inbred males. Independently of the effects of inbreeding, male fitness depended on several male traits, including a sexually dimorphic (flower number) and a gametophytic trait (in vitro pollen germination rate). In addition, full-sib matings were less frequent than randomly expected. Thus, inbreeding, phenotype and genetic dissimilarity simultaneously affect male fitness in this animal-pollinated plant. While inbreeding depression might threaten population persistence, the deficiency of effective matings between sibs and the higher fitness of outbred males will reduce its occurrence and counter genetic erosion.
- Aligning business processes and work practicesPublication . Zacarias, M.; Martins, Paula VenturaCurrent business process modeling methodologies offer little guidance regarding how to keep business process models aligned with their actual execution. This paper describes how to achieve this goal by uncovering and supervising business process models in connection with work practices using BAM. BAM is a methodology for business process modeling, supervision and improvement that works at two dimensions; the dimension of processes and the dimension of work practices. The business modeling component of BAM is illustrated with a case study in an organizational setting.
- A comparação da evolução cíclica de várias zonas geográficas de referência com PortugalPublication . Guerreiro, Raúl Filipe C.; Rodrigues, Paulo M. M.; Andraz, Jorge MiguelEste artigo, visa avaliar o grau relativo de associação existente entre várias economias avançadas, incluindo Portugal. Neste sentido, a evolução cíclica do PIB de Portugal é comparada com a evolução cíclica do PIB de várias economias de referência, tais como a área do euro, Alemanha, Espanha, EUA, França, Grécia, Irlanda, Itália, Japão e Reino Unido, recorrendo ao filtro de Kalman.
- A comparison of the cyclical evolution of various geographic areas of reference with PortugalPublication . Guerreiro, Raúl Filipe C.; Rodrigues, Paulo M. M.; Andraz, Jorge MiguelThis article evaluates the existing relative degree of association among several developed economies, including Portugal. Using the Kalman fi lter the cyclical evolution of GDP in Portugal is compared with the cyclical evolution of GDP from several other economies of reference, such as the euro area, France, Germany, Greece, Ireland, Italy, Japan, Spain, the UK and the US.