• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 70
  • 48
  • 1
  • Tagged with
  • 119
  • 33
  • 31
  • 28
  • 22
  • 17
  • 15
  • 15
  • 15
  • 14
  • 14
  • 13
  • 12
  • 11
  • 10
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Avaliação do custo e da efetividade do hidrogel a 2% no tratamento de úlceras de perna

Rodrigues, Luciana Miranda January 2010 (has links)
Submitted by Fabiana Gonçalves Pinto (benf@ndc.uff.br) on 2015-12-07T14:06:03Z No. of bitstreams: 1 Luciana Miranda Rodrigues.pdf: 2906831 bytes, checksum: c63fff07e6a85a3c8689b9aadbab96a2 (MD5) / Made available in DSpace on 2015-12-07T14:06:03Z (GMT). No. of bitstreams: 1 Luciana Miranda Rodrigues.pdf: 2906831 bytes, checksum: c63fff07e6a85a3c8689b9aadbab96a2 (MD5) Previous issue date: 2010 / Mestrado Acadêmico em Ciências do Cuidado em Saúde / Este estudo teve como objetivos avaliar a efetividade do hidrogel 2% em pacientes com úlceras de perna; estimar o custo médio do uso do hidrogel 2% num período de 90 dias e comparar o custo do uso do hidrogel 2% em pacientes com úlceras de perna com hidrogéis industrializados disponíveis no mercado nacional. Trata-se de um estudo de intervenção terapêutica, prospectivo, do tipo ensaio clínico não controlado sobre a avaliação do uso do hidrogel 2% produzido na farmácia universitária para o tratamento de feridas em pacientes com úlceras de perna. A amostra constou de 20 voluntários, de ambos os sexos, para 90 dias de tratamento com o hidrogel a 2%, totalizando 250 consultas durante o período de fevereiro a outubro de 2010. Este estudo foi encaminhado ao Comitê de Ética em Pesquisa do Hospital Universitário Antônio Pedro sob o parecer CAAE n0 0154.0.258.000-08 e os termos de consentimento livre e esclarecido e de fotografia encontram-se de acordo com as Resoluções n0 196/96 e 251/97 do Conselho Nacional de Saúde. Do grupo amostral, pôde-se identificar que 62,5% dos voluntários eram predominantemente do sexo feminino. A idade média variou de 60,5 anos ± 11,4 e que 52,25% residiam no município de Niterói. Em relação à análise da evolução clínica das úlceras de perna, pôde-se observar que surgiram dois grupos distintos com relação ao tamanho da área da lesão, sendo estas classificadas no estudo como, área 1 – para lesões com tamanho acima de 100 cm 2 e área 2 – para lesões com tamanho abaixo de 100 cm 2. O tecido de maior prevalência na avaliação inicial foi o tecido de esfacelo que apresentou uma média de 3,75 ± 1,2 de presença no leito da lesão dos voluntários do estudo. Destaca-se ainda, que após 90 dias de tratamento com o hidrogel a 2%, foram observadas alterações teciduais importantes para a cicatrização e/ou redução da área lesional (p=0,0416). A presença do tecido de granulação passa a prevalecer com uma média de 3,12 ± 1,0 e 25% dos voluntários obtiveram cicatrização total (100% de tecido de epitelização). Em relação à análise dos custos do tratamento com o hidrogel a 2% destacou-se inicialmente que o tratamento das úlceras pertencentes à área 1 foi maior que a das úlceras da área 2, sendo esta variação de R$114,40 a R$393,23 (M= R$227,55 e Dp=72). Ao comparar o tratamento das úlceras de perna com hidrogel 2% 100 gramas com outros hidrogéis disponíveis no mercado nos valores proporcionais a 100 gramas observou-se uma diferença significativa (p= 0,0003) para os valores referentes às áreas 1 e 2 em todas as perspectivas estudadas. Os valores variaram de acordo com o tamanho das áreas da lesão. A área 1 teve uma variação de preço de R$ 112,85 a R$ 912,11 nas três esferas estudas e a área 2 variou de R$ 70,75 a R$ 558,88 nas três perspectivas do estudo. Ao analisar os custos e a efetividade do uso dessa terapêutica, verificou-se que o hidrogel a 2% apresenta uma efetividade significante assim como os seus custos, não sendo justificável a sua não utilização nos serviços de saúde. O hidrogel a 2% manipulado magistralmente numa farmácia universitária representa uma alternativa para essa situação, uma vez que promove melhora das taxas de cicatrização, com diminuição do tempo de tratamento dessas úlceras, além de ser um tratamento de baixo custo, se comparado a outros hidrogéis industrializados disponíveis no mercado nacional, trazendo menores gastos para os serviços de saúde e órgãos de financiamento. / This study aimed to evaluate the effectiveness of hydrogel 2% in patients with leg ulcers, estimate the average cost of using the hydrogel 2% within 90 days and compare the cost of the use of hydrogel 2% with others hydrogels industrialized. This is a study of therapeutic intervention, prospective clinical trial, uncontrolled on evaluating use of hydrogel 2% produced in the pharmacy college in the treatment of wounds in patients with leg ulcers. The sample consisted of 20 volunteers of both sexes, during 90 days of treatment with the hydrogel to 2% to 250 consultations during the period from February to October 2010. This study was submitted to Committee on Research Ethics at University Hospital on advice CAAE number 0154.0.258.000-08 and terms of consent and photography are in accordance with Resolutions 196/96 and 251/97 of the National Health Council. Of this sample group, could be identified that 62.5% of the volunteers were predominantly female. The mean age ranged from 11.4 ± 60.5 years and 52.25% lived in Niterói. On the analysis of clinical outcome of leg ulcers, it was observed that emerged two distinct groups with respect to the size of the lesion area, which are classified in this study: area1 - for lesions with a size greater than 100 cm2 and area 2 - for lesions with size below 100 cm2. About these group it was noted that the tissue with the highest prevalence at baseline was the desvitalization tissue that showed presence an average 3.75 ± 1.2 of the wound bed. After 90 days by treatment with hydrogel 2%, it has obtained tissue with an important changes to healing and / or reduction area lesion (p = 0.0416). The granulation tissue presence begins to prevail with an average 3.12 ± 1.0 and 25% these volunteers had total healing (100% epithelization tissue). On the costs analysis with hydrogel 2% treatment it has initially the ulcers belonging area 1 was higher than the second area of ulcers, and this variation was the R$ 114.40 to R$ 393, 23 (mean = R$ 227.55 and dv = 72). When comparing the treatment of leg ulcers with hydrogel 2% 100 grams with other commercially available hydrogels in proportionate amounts to 100 grams there was a significant difference (p = 0.0003) for the values related to areas 1 and 2 in all perspectives studied. The values ranged with the size of the lesion areas. The area 1 had a variation in price from R$ 112.85 to R$ 912.11 and the area 2 ranged from R$ 70.75 to R$ 558.88 on the three perspectives of the study. Analyzed the costs and effectiveness using this therapy, it was found that hydrogel 2% shows a significant efficacy as well as their costs are not justified in not using health services. The hydrogel 2% manipulated in a pharmacy college represents an alternative to this situation, since it promotes improved healing rates, decreased treatment time of these ulcers, as well as being a low-cost treatment, as compared to other hydrogels industrialized in the national sale, bringing lower costs to health services.
82

The effect of chronic copper exposure on the energy budget of two mussels, perna viridis (L.) and septifer virgatus (Wiegmann)

Sze, Wai-chung., 施慧中. January 1995 (has links)
published_or_final_version / Ecology and Biodiversity / Master / Master of Philosophy
83

Elaboração de uma linha de cuidado do indivíduo com úlcera crônica de perna, em um município da região metropolitana do Vale do Paraíba Paulista / Elaboration of a Line of Care of the individual with Chronic Leg Ulcer, in a city of the Metropolitan Region of Paulista Paraíba Valley

Balista, Aline Lino 20 December 2016 (has links)
Introdução: As úlceras crônicas de perna (UCP) são um sério problema de saúde que atinge diversas faixas etárias, etnias, sexos, com reflexos nos gastos públicos e interferência na qualidade de vida das pessoas acometidas e de seus familiares. O presente estudo parte da concepção de que há necessidade de uma atenção integral que possa ser estabelecida por meio da utilização e construção de uma Linha de Cuidado. Objetivo: Elaborar coletivamente uma Linha de Cuidado (LC) do indivíduo com UCP em um município do Vale do Paraíba Paulista. Objetivos específicos: discutir os elementos constitutivos do fluxograma da LC e analisar suas dificuldades e potencialidades a partir deste. Metodologia: Pesquisa qualitativa, utilizando-se de 4 oficinas de trabalho realizadas nos meses de novembro de 2015 à março de 2016. Contou com a participação da Coordenação da Atenção Básica, enfermeiros e médicos de Unidades de Saúde da Família, enfermeira responsável pela assistência de indivíduos com úlceras crônicas de perna do ambulatório do município, e enfermeira responsável pela Atenção Domiciliar da Equipe Multiprofissional de Atenção Domiciliar (EMAD). Adotou-se a Integralidade como base conceitual da produção da LC e para a análise dos resultados, o fluxograma analisador. Resultado e Análise: Como resultado principal teve-se a produção coletiva de uma LC do indivíduo com UCP. Foram elementos essenciais na LC: recepção pró-ativa, acolhimento, ações de enfermagem desde a avaliação até os cuidados do indivíduo com UCP, presença de recursos materiais - em especial, na Atenção Primária à Saúde (APS), trabalho multidisciplinar no desenvolvimento do plano terapêutico e contrarreferência. Foram dificuldades e potencialidades: necessidade de programas de educação permanente, fortalecimento da APS para o cuidado, necessidade de articulação entre os serviços para garantir complementariedade e integralidade por meio de instrumentos pactuados, recursos materiais e efetivação do trabalho interdisciplinar. Conclusão: Evidenciou-se que há necessidade de se fortalecer a APS como centro de uma rede, ampliar as atribuições do enfermeiro acerca dos cuidados do indivíduo com UCP, fomentar espaços de diálogo entre os pontos da rede, ou seja, entre aqueles que estariam envolvidos na LC e, ainda, apoio e investimento dos gestores na produção do cuidado presente na LC. É necessário valorizar o potencial de mudança que a LC pode possuir quando existe comprometimento do profissional envolvido no processo do cuidar e a necessária garantia do itinerário terapêutico na rede de atenção em saúde à lógica dos serviços locais. / Introduction: Chronic leg ulcers (CLU) is a serious health problem that affects different age groups, ethnicities, genders, reflected in public spending and interference in quality of life of the affected people and their relatives. This study comes from the conception that there is need of an integral attention, which can be established through the use and building of a Line of Care. Objective: To elaborate collectively a Line of Care (LC) of the individual with CLU in a city of the Metropolitan Region of Paulista Paraíba Valley. Specific objectives: To discuss the components of the LC flow chart and analyze the difficulties and potentialities from this. Method: Qualitative research, using 4 workshops held from November of 2015 to March of 2016. They had the participation of the Coordination of Primary Care, nurses and doctors from Family Health Units, the nurse responsible for the care of individuals with chronic leg ulcers of the municipal clinic, and the nurse responsible for the Attention Homecare of the Multiprofessional Team of Attention Homecare (MTAH). This study adopted the Integrality as a conceptual basis for the production of the LC and for the analysis of the results, the analyzer flow chart. Results and Discussion: As a main result it was the collective production of a LC of the individual with CLU. The essential elements in the LC were: proactive reception, user embracement, nursing actions from evaluation to the care of the individual with CLU, presence of material resources - especially in Primary Health Attention (PHA), multidisciplinary work in developing the therapeutic plan and counter reference. The difficulties and potentiality were: the need for continuing education programs, strengthening PHA for care, the need of articulation between the services for ensuring complementarity and integrality through agreed instruments, material resources and realization of the interdisciplinary work. Conclusion: It was evident that there is need to strengthen PHA as the center of a network, expand nurse assignments about the care of the individual with CLU, foster dialogue among network points, that is, among those who would be involved in the LC and also support and investment by managers in the production of the care in the LC. It is necessary to valorize the potential of change that the LC can have when there is impairment of the professional involved in the care process and the necessary guarantee of the therapeutic route in the network of health attention to the logic of the local services.
84

Úlcera de perna: caracterização clínica e perfil imunohistopatológico da cicatrização na presença da biomembrana de látex natural da seringueira Hevea brasiliensis / Leg ulcer: clinical caracterization and immunohistopathologic profile on wound healing in the presence of natural latex biomembrane of rubber tree Hevea brasiliensis.

Frade, Marco Andrey Cipriani 27 February 2003 (has links)
Úlcera de perna é uma doença muito freqüente na população idosa. Inúmeros são os tipos de curativos atualmente usados para tratamento das úlceras de perna, com diferentes indicações, vantagens e desvantagens, cuja eficácia não está bem esclarecida devido à descontinuidade dos tratamentos e os custos envolvidos em algumas situações. Para avaliar a ação da biomembrana de látex (BML) no tratamento de úlceras de perna, que se comportou como eficiente indutora do tecido de cicatrização. Foram realizadas avaliações clínicas e imunohistopatológicas em 21 doentes, casualmente selecionados, submetidos à aplicação da biomembrana (14 pacientes), comparando com o tratamento clássico (07 pacientes) constituído de pomada com cloranfenicol e enzimas proteolíticas (Fibrase) com o objetivo de analisar e comparar as alterações histopatológicas e imunohistoquímicas relacionadas aos diferentes tratamentos. Foram coletadas biópsias da lesão antes e 30 dias após os tratamentos. As biópsias foram divididas em dois fragmentos, um deles para o estudo histopatológico e outro congelado a -70°C para análise imunohistoquímica. Os resultados mostram que o uso da biomembrana de látex facilitou os cuidados à lesão aliada ao baixo custo e praticidade de sua aplicação. Adicionalmente, foi observado que a BML induz a uma diferenciação clínica e histopatológica do tecido de cicatrização, com aumento da detecção de fatores de crescimento como VEGF (vascular endothelial growth factor) e TGF1(transforming growth factor 1), associada à redução da expressão da enzima iNOS (óxido nítrico-sintase induzida), quando comparado ao tratamento controle. A análise global dos dados sugere que o tratamento com a biomembrana conduz a organização do tecido cicatricial conseqüente à maior produção de fatores de crescimento celular. Dessa forma, a biomembrana se caracteriza como uma boa opção terapêutica para úlcera de perna, devido à praticidade de sua aplicação, baixo custo e alta potencialidade na indução da cicatrização. / The leg ulcer is a disease very frequent in elderly people. Nowadays, there are many kinds of dressing to treat its with different indications, advantage and disadvantage. Their efficacy is not clear yet because to the treatments discontinuous and the costs involved in same situations. The latex biomembrane from rubber tree Hevea brasiliensis (NLB) showed an improvement of the healing process to treat leg ulcer, observed by the clinical and the immune histopathological aspects. To verify whether the NLB could be associated with an increased healing we selected 21 leg ulcer patients to be submitted to the topical treatment. These patients were divided into two groups. In the first group 14 randomized patients were treated with latex biomembrane and in the other group 07 patients were treated with topical ointment of cloranfenicol and proteolitic enzymes with the objectives to analyze and to compare the histopathological and immunohistochemical alterations related to the different treatments. All the patients were submitted at least to two biopsies; before the treatment and the 30th day of the treatment. The biopsies specimens were divided into two parts; one of them for the histopathological study and the other was frozen for the immunohistochemical analysis. The results showed that the biomembrane is very easy, practical and cheap leg ulcer topical treatment. Additionally, the NLB induces to a clinical and hystopathological differentiation of the cicatrization tissue with increased detection of growth factors as VEGF (vascular endothelial growth factor) and TGF-1(transforming growth factor1), associated to a reduction of iNOS (induced oxide nitric sintase) expression when compared to the control treatment. The global analyze of the data suggest that the biomembrane of natural latex led to cicatricial tissue organization and a higher production of cellular growth factors. So, this treatment can characterize as a good therapeutic option for leg ulcers due the facility of the application, low costs and high potentiality to induce of the cicatrization.
85

"Fisioterapia na cicatrização e recuperação funcional nos portadores de úlcera de hipertensão venosa crônica: uso da estimulação elétrica com corrente de alta voltagem" / Physical therapy in cicatrization and functional recovery of chronic venous hypertension ulcer bearers : the use of electrical stimulation by means of high voltage current

Pires, Eliane Jeronimo 15 September 2005 (has links)
O objetivo deste trabalho foi avaliar os efeitos da estimulação elétrica com corrente de alta voltagem na cicatrização da úlcera de hipertensão venosa crônica, bem como na dor referida, em 13 pacientes portadores de 20 úlceras. Os pacientes diferiram quanto à variação da área da ferida ao longo do tratamento. As curvas individuais indicaram a eficácia do estudo. Dos 13 pacientes que participaram do estudo, observamos que em quatro as feridas cicatrizaram totalmente, enquanto em seis elas reduziram o seu tamanho e em três, aumentaram. Não foram observados efeitos adversos causados pela eletroestimulação. A dor apresentou melhora significativa ou cessação em todos os pacientes / The objectives of this study was to evaluate high voltage electric stimulation effects over chronic venous hypertension ulcer, as well over the referred pain, in 13 patients bearing 20 ulcers. The patients have differed among themselves in relation to the ulcer area throughout the study. The individuals curves indicated the treatment efficacy. It was observed that the ulcer area have been healed in four patients, reduced in six and increased in three of the thirteen patients who has participated in this study. It was not observed adverse effects due to electrical stimulation. The pain has showed meaningful advance or ceasing in all patients
86

Derivation of environmental quality guidelines based on tissue burden of toxic pollutants in the green lipped mussel Perna viridis

Chu, King-hei, Vincent., 朱景熹. January 2006 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
87

Physiological Effects and Biotransformation of Paralytic Shellfish Toxins in New Zealand Marine Bivalves

Contreras Garces, Andrea Maud January 2010 (has links)
Although there are no authenticated records of human illness due to PSP in New Zealand, nationwide phytoplankton and shellfish toxicity monitoring programmes have revealed that the incidence of PSP contamination and the occurrence of the toxic Alexandrium species are more common than previously realised (Mackenzie et al., 2004). A full understanding of the mechanism of uptake, accumulation and toxin dynamics of bivalves feeding on toxic algae is fundamental for improving future regulations in the shellfish toxicity monitoring program across the country. This thesis examines the effects of toxic dinoflagellates and PSP toxins on the physiology and behaviour of bivalve molluscs. This focus arose because these aspects have not been widely studied before in New Zealand. The basic hypothesis tested was that bivalve molluscs differ in their ability to metabolise PSP toxins produced by Alexandrium tamarense and are able to transform toxins and may have special mechanisms to avoid toxin uptake. To test this hypothesis, different physiological/behavioural experiments and quantification of PSP toxins in bivalves tissues were carried out on mussels (Perna canaliculus), clams (Paphies donacina and Dosinia anus), scallops (Pecten novaezelandiae) and oysters (Ostrea chilensis) from the South Island of New Zealand. Measurements of clearance rate were used to test the sensitivity of the bivalves to PSP toxins. Other studies that involved intoxication and detoxification periods were carried out on three species of bivalves (P. canaliculus, P. donacina, P. novaezelandiae), using physiological responses (clearance and excretion rate) and analysis of PSP toxins in the tissues over these periods. Complementary experiments that investigated other responses in bivalves fed with the toxic cells were also carried out. These included byssus production, and the presence of toxic cells in the faeces of mussels, the siphon activity and burrowing depth in clams and the oxygen consumption in scallops. The most resistant species to PSP toxins were the mussel, Perna canaliculus and the clam, Dosinia anus. Both species fed actively on toxic dinoflagellates and accumulated toxins. The intoxication and detoxication rate of the mussel was faster than the other species of bivalve studied (P. donacina and P. novaezelandiae) which confirm mussels as a good sentinel species for early warning of toxic algal blooms. The clearance rate of the clam, Paphies donacina decreased when fed on Alexandrium species but the effect of the PSP toxins on this physiological response was not confirmed. Over the detoxification period of 8 days, this clam did not detoxify which suggests that its ability to retain high level of toxins for an extensive period may be critical for public health management. The scallop, Pecten novaezelandiae was clearly the most sensitive species to the PSP toxins and the clearance rate was significantly lower in the presence of the toxic dinoflagellate A. tamarense. Although the clearance rate was low, the scallops still fed on the toxic dinoflagellate and accumulated PSP toxins in the tissues. The scallops detoxified slowly which would affect the market for this bivalve in the presence of a toxic algal bloom. This bivalve would retain PSP toxins for longer period of time than other species such as mussels. The oyster, Ostrea chilensis, had erratic clearance rate and did not respond clearly to any of the variables tested over the time. Oysters accumulated more toxins than the sensitive species, but they had been exposed to two more days of feeding with A. tamarense; therefore this species may actually have a similar intoxication responses to P. novaezalandiae and P. donacina. The results from this thesis suggest further directions for the aquaculture sector and ongoing research in this field, which in future will lead to a better selection of suitable species for culture as well as species for monitoring of PSP toxins. In the future, research that integrates field and controlled laboratory studies will expand to other species of interest and a more complete record will in time be available in order to manage more efficiently the negative effects that harmful algal blooms may have in New Zealand.
88

Effects of environmental stress on gene expression in mussels

Callander, Davon Christina January 2012 (has links)
The biogeographic distribution of organisms is determined by physiological characteristics that enable a population to persist in a specific location. Global climate change effects are anticipated to increase the physiological stress experienced by organisms. Consequently, it is important to understand physiological responses to environmental stress and the mechanisms used by animals to cope with variable conditions. I investigated the physiological response to environmental stress in two species of mussel from New Zealand, Perna canaliculus and Mytilus galloprovincialis, using quantitative PCR and ecological field experiments. A series of laboratory and field experiments were done to manipulate stress levels and the expression levels of three heat shock protein genes (hsp24, hsp70, hsp90) were measured. A transcription regulatory gene (elf2) and a cell cycle regulatory gene (tis11d) were also measured. The dynamics of stress response gene expression in response to acute stress and gene expression changes in the natural population due to varying forms of environmental stress were tested. Between-zone translocations of different sized M. galloprovincialis and P. canaliculus were done at two sites in both east and west regions of the South Island of New Zealand. Site was found to be the most important factor in stress response. Apparent low food and high exposure stress interacted to create the particularly elevated stress response at the Timaru site. The adaptive ability of mussels transplanted between sites with varying environmental conditions was also tested. Results suggest that acclimation may be limited under stressful conditions. Furthermore, I found that P. canaliculus, the predominantly low-zone species, had a lower stress response than M. galloprovincialis, which was contradictory to predictions. The investigations described in this thesis suggest that interactive effects of abiotic stress and food limitations are particularly challenging for animals. With the severity of climate change scenarios predicted, changes in water quality and aerial and seawater temperature suggest mussel populations are likely to be negatively affected in the future. This work also illustrates the great potential to utilise molecular techniques for analysis of physiological processes of non-model organisms in a real-world setting.
89

The effects of the invasive mussel mytilus galloprovincialis and human exploitation on the indigenous mussel Perna perna on the South Coast of South Africa

Rius Viladomiu, Marc January 2005 (has links)
In South Africa, the indigenous mussel Perna perna is threatened by both an invasive species and excessive human exploitation. The Mediterranean mussel Mytilus galloprovincialis is an invasive species that has been introduced to many parts of the world. In South Africa, this species arrived in the 1970s and spread rapidly along the west coast where today it is the dominant mussel species. Along the west coast, M. galloprovincialis is competitively superior in all aspects to the indigenous mussel species, and, as a result, has displaced some of them. On the south coast, M. galloprovincialis found more oligotrophic waters, higher species richness, and a stronger competitor in the indigenous mussel P. perna. The rate of spread of M. galloprovincialis along the south coast has decreased over the last 10 years and the present eastern limit of its distribution in South African is East London. On the south coast, M. galloprovincialis has not yet completely replaced P. perna; instead, the two exhibit spatial segregation, with P. perna dominating the low shore, M. galloprovincialis the high shore and an overlap zone between the two. An experiment on competition was carried out at one site on the south coast. The results showed that, on the low shore, P. perna is a more dominant competitor for space than M. galloprovincialis. Also byssus attachment of the two species differs, P. perna being much stronger than M. galloprovincialis, which suffers high mortality due to wave action on the low shore, especially in monospecific beds. As a result, mortality of M. galloprovincialis through wave action is reduced by the presence of P. perna, which seems to confer protection against dislodgement. However, in the absence of strong wave action, P. perna competitively excludes M. galloprovincialis. Human exploitation along 160 km of coast was examined by sampling mussel populations and using aerial surveys to determine where harvesters were distributed. Collectors did not seem to discriminate between species. The study has shown that higher abundances of mussels were found in protected or inaccessible sites, while in unprotected sites mussels were scarce. Coastal nature reserves are being proven to be effective in protecting mussel populations.
90

Intertidal patterns and processes tracking the effects of coastline topography and settlement choice across life stages of the mussels perna perna and mytilus galloprovincialis

Von Der Meden, Charles Eric Otto January 2010 (has links)
Within landscapes, spatial heterogeneity is common and specific landscape features can influence propagule dispersal by wind or water, affecting population connectivity and dynamics. Coastline topographic features, such as bays and headlands, have a variety of biophysical effects on nearshore oceanography, larval transport, retention and supply, and the processes of larval settlement and recruitment. Although this has been demonstrated in several parts of the world, engendering a perception of a general ‘bay effect’, few studies have investigated this generality in a single experiment or region, by replicating at the level of ‘bay’. The Agulhas biogeographic region of the south coast of South Africa is a useful system within which to test for such generality. Using the intertidal mussels Mytilus galloprovincialis and Perna perna as model organisms, patterns of adult distribution were surveyed across four large ‘halfheart’ bays and intervening stretches of open coast, providing replication at the level of ‘bay’ and duplication of ecologically similar species. In support of a general, pervasive influence of bays on intertidal populations, mussel cover was found to be greater in bays than on the open coast for both species, although the effect was strongest for M. galloprovincialis. To explain this adult distribution, settlement, post-settlement mortality and recruitment were examined over 12mo at the same sites, with the prediction that rates of each would favour larger bay populations. Contrary to this, an interaction between month and bay-status was found, with greater settlement and recruitment on the open coast than in bays reflecting extreme settlement and recruitment events at 3 westerly open coast sites during summer. Re-analysis excluding these outliers, revealed the expected effect, of greater settlement and recruitment in bays. While this indicates the broad generality of the bay effect, it highlights exceptions and the need for replication in time and space when examining landscape effects. Measuring post-settlement mortality required testing small-scale settlement behaviour on established and newly deployed settler collectors. It was found that all settlers preferred collectors with biofilm, but that primary settlers avoided conspecific settlers, while secondary settlers were attracted to them. With discrepancies in settler attraction to new and established collectors accounted for, initial (over 2d) and longer-term (over 7d) post-settlement mortality rates were found to be substantial (ca 60 %) for both species. No topographic effect on p-s mortality was evident. Finally, recruit-settler, adult-recruit and interspecies correlations were examined at regional and local scales. Synergistic (or neutral) effects maintained the initial settlement pattern in recruit and adult populations regionally, but not at local scales; striking interspecies correlations suggested the influence of common regional transport processes. Ultimately, the results emphasize the importance of the direction of effects in different life stages and at different spatial scales, and the possibility that antagonistic effects may mask even strong patterns.

Page generated in 0.044 seconds