Browsing by Issue Date, starting with "2021-11-05"
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- Short-beaked common dolphins (Delphinus delphis ) in São Miguel Island, Azores: photo-identification of highly Identifiable Individuals (HII) and spatiotemporal distributionPublication . Brandão, Milla Silveira Pinto; Costa, Bárbara Bastos Horta e; González García, LauraShort-beaked common dolphin, Delphinus delphis, is a well distributed species worldwide and one of the most sighted species in the Azores archipelago. However, there are no studies focusing on their photo-identification or residency patterns in the region. The main objectives of this thesis are to assess the spatio-temporal distribution of common dolphins around São Miguel and identify the Highly Identifiable Individuals (HII) to analyze their residency patterns. To do so, we used opportunistic data, both sightings and photographs, collected by Futurismo Azores Adventures during whale watching trips between May 2008 and March 2020 in São Miguel (Azores). Common dolphins were encountered year-round with lower encounter rates in summer time and reflect on a possible displacement caused by Atlantic spotted-dolphins. They were mostly found in shallow waters (69% at < 450 m) and close to the shore (61% at < 5 km). Calves were present year-round, but mostly in summer likely due to higher water temperature and availability of food. A total of 5.698 photos were processed and visually compared to create a catalogue with the HII individuals, which contains 402 right dorsal fins, 472 left dorsal fins, and 72 individuals identified by both sides. About 87% of the individuals identified were sighted only once and considered transients. From the resighted 13%, 47% were residents or sighted in several seasons in several years; 10% seasonal residents or sighted only in one season in several years; and 43% transient or sighted within a year. Long-lasting potential associations between individuals are suggested based on the same dates of occurrence over the study period, with a maximum re-sighting interval of 4 years. These findings provide evidence of resident individuals of common dolphins in a busy coastal area of São Miguel. Therefore, further research would be of help to support appropriate management plans in the future.
- Spatial and temporal distribution and potential residency of bottlenose dolphins (Tursiops truncatus) off São Miguel Island, AzoresPublication . Catalão, Rita; Vinagre, Catarina; González García, LauraThe common bottlenose dolphin (Tursiops truncatus) is a cosmopolitan cetacean species distributed all over the world, except in the poles. This species is also one of the most sighted in the island of São Miguel, Azores, however it is still poorly studied. This thesis describes the spatial and temporal distribution of bottlenose dolphins sighted off São Miguel and presents a catalogue with the individuals identified between 2014 and 2019. Furthermore, their degree of residency around the island of São Miguel is also assessed. Data was collected using as opportunistic platforms of observation the whale watching boats of Futurismo Azores Adventures, a company with main base port in Ponta Delgada, on the south of the island. Two datasets were used: the first includes the information from the bottlenose dolphin sightings registered between 2010 and 2019, and it was used to analyse spatial and temporal distribution of bottlenose dolphins around the island; the second dataset includes pictures taken during the whale watching trips from 2014 until 2019, and it was used to build a catalogue with the individuals identified during that period, look for residency patterns and associations among the residents. The results revealed a preference for shallower waters indicating a higher number of sightings in depths lower than 500m. The presence of bottlenose dolphins varied between seasons and inter-annually, with higher occurrences during the warmer months. This pattern has been seen in other studies and it could be related to higher concentration of prey after a peak in phytoplankton in the previous months. From the 505 individuals identified only 52 dolphins were considered residents. Within these dolphins there were four possible associations between several individuals based on the dates they were encountered on. This study is the first to present a catalogue with individuals from São Miguel and one of the first to analyse the spatial and temporal distribution of bottlenose dolphins in the island. Further research would be needed to contribute to the overall knowledge of this species in São Miguel and support proper management and conservation plans for the species in this area.
- The role of lithic raw materials on tool performance and use: The efficiency and durability on stone tools edgePublication . Nora, David André Cabrita Nora; Aldeias, Vera; Marreiros, João MarreirosUnderstanding and identifying the use of stone artifacts found in the archaeological record has long been one of the main focus on the study of lithic technology. Thus, investigating the use of stone tools is critical for interpreting and reconstructing the prehistoric subsistence and behavioural patterns in archaeological investigation. The evaluation of the physical and mechanics principles underlying the question of why a particular rock type is preferred over another for the production and use of stone tools, or questions regarding the interaction between the acquisition of a particular type of lithic raw material to obtain a flake with a sharper edge was one of the main daily decision-making processes of past hominins. So, this type of action suggests predisposed know-how of lithics raw materials behave. Although not fully understood, several studies have shown that the relationship between the properties of lithic raw material and the use of stone tools has been shown to be directly related. The aim of this master's thesis is therefore to explore the interaction between the use of stone tools by prehistoric populations and their adaptability to different raw materials, using two distinguished groups coarse-grain and fine-grain rock types as main evidence. All lithic raw materials were evaluated by an experimental design regarding their efficiency and durability. At the same time, a methodology combining experimental replication and material analysis to address this issue will be presented and proposed. The controlled experimental program conducted in this thesis was designed to determine the efficiency and durability of four lithic raw materials - quartzite, flint, obsidian, and dacite. This work builds on a preliminary experiment by Pedergnana et al., 2019, which investigated the use of flint and obsidian in scraping movements. Following the initial observations made by Pedergana and colleagues, the present study aims to take the next step by introducing greater variability of raw materials and a new motion, cutting against a new contact material (wood). The experiment is conducted using a mechanical device (SMARTTESTER®) that mimics the human cutting motion, in this particular case a bidirectional longitudinal movement. The experimental plan is divided into three phases: 1) Characterization of the raw material, 2) Experiment that mimics the cutting process and quantifies the number of variables, 3) Data analysis to nullify the null hypothesis "efficiency does not vary according to the different lithic raw materials". The ability to bring new quantifiable data to consider efficiency and durability of stone tools shows that the methodology used is suitable to address these issues and can be expanded to other research questions. The results presented show that all lithic raw materials reveal their efficiency in performing a cutting movement in pine wood in the first 250 strokes. Flint proved to be the most resistant lithic raw material tested in this experiment, being the most durable and efficient after 1000 strokes. Quartzite showed a fragmentation pattern, while obsidian, being a very brittle raw material, likely shows a relationship with a technological feature in his reduction when performing bidirectional movements in wood. Dacite proved to be a good substitute for flint due to its homogeneous hardness values and consistent performance after passing through all cycles. The development of the work described in the above phases will allow to understand and quantify the efficiency and durability of each lithic raw material. These data can contribute to various topics in lithic studies, such as edge durability, reduction sequences, retouch intensity, and raw material sourcing and optimization strategies. Furthermore, this study aims to integrate a free database on an open-access platform to compare the obtained results with stone tools from other archaeological sites. As a possible case study, Kalavan 2 a Middle Paleolithic open-air site with an assemblage composed of obsidian, chert, basalt, limestone, and welded tuff associated with woodworking by use-wear studies is included in the discussion of this thesis as an example of continuous work on this topic.
- Manual de Acolhimento e Integração dos colaboradores do Monte Rei Golfe & Country ClubPublication . Guerreiro, Estela Rosa Custódio; Gonçalves, Gabriela; Viegas, MargaridaNa gestão de Recursos Humanos torna-se essencial o processo de socialização e integração dos novos colaboradores. O momento de integração entre a entidade empregadora e o novo membro da organização, origina um processo de adaptação recíproca onde ambos efetuam um compromisso e cedências entre as partes. O mesmo acontece no processo de socialização organizacional, que adquire uma conotação fundamental e encontra-se interligada com o processo de integração, uma vez que o sucesso, de uma, influencia o êxito da outra. Uma das estratégias efetuadas para a integração e socialização de um novo colaborador compreende a entrega de um manual de acolhimento no momento da admissão. De forma a constituir um recurso ao acolhimento e integração e socialização do novo colaborador, é necessário que este manual de acolhimento contenha todos os dados que a entidade considere como essencial para a introdução do recém-admitido na estrutura organizacional. Assim, considerando que a empresa selecionada não dispõe de um manual de acolhimento, torna-se essencial a sua construção, constituindo o objetivo deste projeto. O manual de acolhimento foi elaborado com base em dois estudos, um de carácter quantitativo de diagnóstico relativo à perceção de socialização organizacional na integração dos novos colaboradores e um estudo qualitativo referente à análise de conteúdo de 6 manuais de acolhimento de empresas similares. Os resultados provenientes da análise dos dados revelaram que a existência e entrega de um manual de acolhimento (bem como a dinamização de outras ações, tais como formações, entre outras) são percebidas pelos trabalhadores como potenciais facilitadores do processo de socialização e integração. A análise dos 6 manuais mostram consistência dos conteúdos a incluir num manual de acolhimento. Em conjunto, um outro ficheiro que também poderá auxiliar neste processo consiste na entrega de um protocolo de acolhimento e integração, onde explicita as etapas, sequências, procedimentos e dados relevantes para a integração do funcionário.
- The effects of a marine heatwave on seagrasses cymodocea nodosa and zostera marina in Ria Formosa, Portugal: photosynthetic activity & oxidative stress indicatorsPublication . Deguette, Alizé; Silva, João Miguel Sousa da; Barrote, IsabelSeagrasses play a high ecological role and provide a large range of ecosystem services, yet they are globally threatened by climate change. The seagrasses Zostera marina and Cymodocea nodosa share the same ecological niche in Ria Formosa, Southern Portugal, where their thermal distribution limits meet. While C. nodosa has its northern distribution limit in Portugal, Z. marina reaches its southern distribution limit in Ria Formosa. The present work aims to comparatively evaluate the physiological responses of both species to marine heatwaves (MHWs), a phenomenon that is increasing in frequency and intensity with climate change. Shoots of both species were transplanted into a mesocosm experiment where a MHW was simulated. The heatwave design was composed of a heating ramp from 20 to 28 °C, a 7-days heatwave at 28 °C, followed by a cooling ramp and an 8-days recovery period at 20 °C. The potentially stressful effects of the MHW on the plant’s physiology were investigated, both during the MHW peak and after recovery. Photosynthetic performance was assessed with photosynthesis-irradiance (P-I) curves parameters (α, Pm and Ik) and chlorophyll fluorescence imaging (CFI). Complementarily, key biochemical stress indicators (Total phenols, TEAC, ORAC, MDA) were quantified to investigate the oxidative stress level in plant tissues. Only C. nodosa survived the acclimation period. The maximum quantum yield of photosystem II (ΦPSII) was enhanced during the heatwave, probably to maintain the photosynthetic activity at control level. Negative effects on the photosynthetic performance of C. nodosa were observed after recovery, whereas ΦPSII came back to control level. No significant oxidative stress was observed all along the experiment. Overall, although C. nodosa showed a relatively high tolerance to MHWs compared to other species such as Z. marina, C. nodosa population in Ria Formosa is likely to be negatively affected by the forecasted climate change scenarios.
- Generation of drug-resistant cell lines as a model to study pancreatic cancerPublication . Grenho, Inês Filipa Acácio; Ferreira, Bibiana I.; Link, WolfgangPancreatic cancer (PC) is among the most aggressive cancers in the world, characterized by an extremely high mortality/incidence ratio. Besides its aggressiveness, PC is usually diagnosed in an advanced and metastatic stage, which limits the treatment options available. Most of these tumors are unresectable by surgery, thus chemotherapy remains the only option available for treatment. However, a majority of these patients relapse within months and have a recurrence of the disease, usually more aggressive and no longer sensitive to the initial treatment. The major responsible for this relapse is the development of acquired therapy resistance. Our work focused on generating cell lines resistant to the current first line chemotherapy drug, Gemcitabine, and on their characterization. This allowed us to generate tools that will be crucial to unveil the mechanism driving acquired resistance in PC. Previous studies from our group and others demonstrated an association between the expression profiles of TRIBBLES pseudokinases and drug resistant phenotypes in other cancers. We evaluated the sensitivity of the generated cell lines to Gemcitabine and characterized them in terms of migration ability, cell death rate under stress and the expression of TRIBBLES proteins and EMT markers. Our results show that we successfully generated Gemcitabine-resistant cell lines, and that these cell lines are phenotypically different from the sensitive ones, showing fibroblastic-like features. Furthermore, we observed a reversible phenotypic switch when these cells undergo Gemcitabine treatment. They show different migration ability and increased mRNA expression of EMT markers, a hallmark of the epithelial-to-mesenchymal transition process. Moreover, in the resistant cells we observed higher TRIB2 protein expression levels and a decrease in the TRIB3 protein expression, compared with the sensitive cell lines. Overall, the phenotype associated with the resistant cells is concordant with drug resistance development by chronic Gemcitabine exposure.