The role of individual foraging specialization in the trophic relationships between seabirds and the marine environment

Tese de doutoramento em Biociências, ramo de especialização de Ecologia Marinha. apresentada à Faculdade de Ciências e Tecnologia da Universidade de CoimbraTrophic relationships are central in ecology and play a crucial role in species survival, as availability of food resources varies over time and space. The spatio-temporal variation in food sources at sea has many ecological implications on marine top predators such as seabirds. However, most ecological studies of resource use and population dynamics treat conspecific individuals as ecologically equivalent, but intra-specific variation in individual foraging strategies can be large and many apparently generalized populations are in fact composed of specialized individuals that use a small subset of the available resources over time (individual consistency). Studies on the incidence of individual specialization suggest that it may vary among species and among populations, but they are scarce, particularly for seabirds, and the mechanisms that generate inter-individual variation are not well understood. The main goal of this study is to corroborate the existence of individual specialization over time in three different species from four seabirds’ populations exploiting different marine environments. Furthermore, it investigates whether individual specialization is associated with the environment and resources exploited and assesses its ecological implications at the population and individual levels. The hypothesis of this thesis was tested using wandering albatross Diomedea exulans, Cory’s shearwater Calonectris diomedea and yellow-legged gull Larus michahellis as model seabird species, and fieldwork was conducted respectively in Bird Island (South Georgia, Antarctica), Corvo Island (Azores archipelago, Portugal) and Berlenga Island (Portugal). Two populations of Cory’s shearwater were studied, one from an oceanic environment (Corvo Island) and other from a neritic environment (Berlenga Island). A total of 199 birds were sampled during the breeding season of each species, from 2009 to 2012. Together with conventional dietary methods a combination of intrinsic and extrinsic markers were used, such as stable isotope analyses (from tissues with different turnover rates) and electronic devices (GPS loggers), to corroborate the existence of individual specialization and examine its relative incidence. Using three environmental parameters (bathymetry, sea-surface temperature and chlorophyll a concentration) to characterize marine habitats and recent developments based in a Bayesian framework, namely stable isotope mixing models (Stable Isotope Analysis in R: SIAR) to estimate individual prey consumption, and recent metrics to estimate populations’ niche width (Stable Isotope Bayesian Ellipses in R: SIBER), data were analysed to investigate ecological implications of individual specialization and its relationships with the environment and resources exploited. Patterns of individual consistency in habitat use and/or prey consumption were found in all studied species. However, these patterns varied spatio-temporally according to the population, evidencing the role of individual specialization in the foraging dynamic of these species. Inter-annual differences in the feeding ecology and foraging behaviour of birds during the breeding season were associated with the availability of food resources around the colonies, which influenced the patterns of individual consistency in Cory’s shearwater, but not in yellow-legged gulls. Results also suggest that these differences could have an impact on the reproductive performance of Cory’s shearwater and on the body condition of the yellow-legged gulls, but evidences of relationships between these ecological consequences and individual specialization at the individual level were not found. Overall, this study corroborates the existence of individual specialization over time within studied seabird populations. Therefore, such trait may be potentially widespread across several related seabird species. Such consistency, however, varied among species and populations and results showed that it was more stable in yellow-legged gulls than in Cory’s shearwaters. Fluctuations on individual consistency were related to temporal changes in the availability and predictability of resources, which means that the more specialized species may be more sensitive to that. It also corroborates that individual variability within a seabirds’ population may be regulated by small differences in breeding location (< 2km), suggesting that studies assuming a colony or sub-colonies as ecologically homogeneous in terms of foraging ecology can be biased. This study supports the hypothesis that individual specialization may have important ecological implications, such as the reduction of intra-specific competition and, consequently, a high impact on ecological processes and foraging dynamics. Further investigation is required to identify the mechanisms that generate individual specialization and its ecological implications at both population and individual level.Fundação para a Ciência e Tecnologia (FCT) - SFRH/BD/64558/200

Equity valuation using accounting numbers in high and low market cap companies

Most firms’ and individual analysts’ decisions depend on information obtained by valuation to make assessments. The several factors influencing that same valuation process are not always straightforward, and a small difference in methodologies used, time period considered or even assumptions made, can dictate a difference in the agent’s economic decisions. The present dissertation proposes to ascertain which models of equity valuation based on figures from accounting procedures put up a better alternative on explaining market prices when a market capitalization division (small/large) is put in place. Four different methodologies are compared in terms of efficiency, usability and limitations, two of those being stock-based models while the other two flow-based ones. A literature review is firstly conducted to identify previous research on the matter, highlighting the superior theoretical background of flow-based methods, especially the RIVM and OJ Model, due to their attractiveness to the use of the net income figure rather than a derivation. On the following section, a large sample examination is performed, with an analysis of errors, explanative power, sensitivity to small variable changes and even industry sub-divisions. Using the market price as reference, the Price to earnings multiple model has yielded the best results across the board, despite the differences in performance found across the divisions implemented. Also, a small sample analysis is conducted, in which a set of forty broker’s reports is chosen to ascertain if the small/large market cap division is also considered by practitioners when issuing recommendations. Although some differences are found, the main dissimilarity seems to be more closely related to the brokerage houses own preferences than to firm size, but inherit limitations on this type of analysis do not allow for definite conclusions

Desenvolvimento de membranas catalíticas para a produção de aroma de jacinto a partir de glicerol

Dissertação para obtenção do Grau de Mestre em Engenharia Química e BioquímicaA síntese de aromas representa um elevado volume de negócios na indústria alimentar e dos cosméticos. Dentro do conceito de bio-refinaria, tem interesse o aproveitamento do glicerol, matéria prima abundante e barata, subproduto da produção de biodiesel. O aroma de jacinto pode ser sintetizado por acetalização do fenilacetaldeído com o glicerol, por catálise ácida. Como se trata duma reacção reversível, é limitada pelo equilíbrio, tendo sido proposta a destilação azeotrópica como forma de maximizar a conversão. Neste trabalho, como alternativa à destilação azeotrópica, estuda-se a aplicação dum reactor de membrana catalítica polimérica à acetalização do fenilacetaldeído com glicerol. Este tipo de reactor permite a integração da reacção e da separação numa única operação, assim como a exclusão de solventes do processo. Tem, além disso, a vantagem de apresentar menores gastos energéticos. Foi efectuado o estudo cinético da reacção de acetalização catalisada pelo zeólito H-USY, a diferentes temperaturas. Seleccionou-se um modelo cinético por análise de variância e realizaram-se estudos de estabilidade do catalisador. Prepararam-se membranas catalíticas compósitas por dispersão de zeólito H-USY em matrizes de poli(álcool vinílico) (PVA) reticulado com aldeído glutárico. Modificou-se o balanço hidrofílico/hidrofóbico de algumas das membranas compósitas previamente preparadas, por tratamento com anidrido acético. As membranas foram caracterizadas por medição do inchaço, do ângulo de contacto, e por FTIR, SEM e AFM. Os efeitos da carga de catalisador, reticulação e balanço hidrofílico / hidrofóbico, na actividade catalítica, foram estudados em reactor batch, com as membranas cortadas em pequenos pedaços. A modelação cinética permitiu avaliar os efeitos daquelas características nas propriedades de sorção e transporte das membranas. Finalmente, as membranas foram testadas em reactor de membrana plana, usando-se azoto seco, na câmara de permeação, como gás de varrimento

Conceções e práticas de aprendizagem autorregulada de professores de 1º ciclo do ensino básico

É cada vez mais fulcral aprender a aprender, o que implica um papel mais ativo por parte dos/as alunos/as e uma maior autonomia relativamente ao processo de aprendizagem. Tal é promovido através do desenvolvimento e implementação da aprendizagem autorregulada em contextos educacionais configurando-se o papel do/a professor/a fundamental para a sua implementação e desenvolvimento. A aprendizagem das competências autorregulatórias deverá começar durante os primeiros anos de escolaridade cabendo ao professor/a a responsabilidade de criar oportunidades e ambientes de aprendizagem favoráveis a que os alunos/as as desenvolvam. Este estudo pretende conhecer como os/as professores/as do 1ºciclo concebem a autorregulação da aprendizagem dos seus alunos/as e o que fazem para a promover. Foram realizadas 16 entrevistas, objeto de análise qualitativa e quantitativa. Os principais resultados indicam que a maioria dos/as professores/as têm conhecimento, conceções e práticas, ainda que de forma incipiente e pouco sistematizadas, sobre aprendizagem autorregulada; Conceptions and Practices of Self-Regulated Learning by Primary School Teachers Abstract: It is becoming increasingly important to learn how to learn, which implies a more active role for the students and greater autonomy in relation to the learning process. This is promoted through the development and implementation of self-regulated learning in educational settings and the role of the teacher is crucial for its implementation and development. The learning of self-regulatory skills should start during the early years of schooling, and the teacher is responsible for creating opportunities and learning environments that are favourable for students to develop them. This study aims to find out how primary school teachers conceive their students' selfregulated learning and what they do to promote it. Sixteen interviews were conducted, subject to qualitative and quantitative analysis. The main results indicate that most teachers have knowledge, conceptions and practices, although in an incipient and unsystematised way, about self-regulated learning

Stable Isotope Dynamics (δ13C and δ15N) in Neritic and Oceanic Waters of the North Atlantic Inferred From GPS-Tracked Cory’s Shearwaters

Intrinsic markers, such as stable isotopes, are a powerful approach to trace wildlife movements because they do not require initial marking of the organism. The main limitation of the isotopic method is the lack of knowledge in spatio-temporal patterns and dynamics of stable isotopes in marine environments, especially at local scales. Here, we combine GPS-tracks and isotopic signatures from Cory’s shearwaters as a model species to define isoscapes in the North Atlantic, and assess δ13C and δ15N dynamics, from local to regional spatial scales. Tracking data and blood samples were collected seasonally (during pre-laying and chick-rearing periods) across 6 years (2010–2015) from a total of 191 birds breeding at both neritic and oceanic environments. Tracked birds encompassed a large latitudinal and longitudinal area of the mid-North Atlantic, from the Eastern to Central North Atlantic. Overall, the δ13C and δ15N values of birds’ plasma over the region ranged from -20.2 to -16.2‰, and from 10.8 to 15.5‰, respectively. As expected, strong biogeographic isotopic patterns were found in δ13C values at a regional scale, mostly driven by an inshore/offshore gradient and chlorophyll a concentration. Although a moderate expression of spatial isotopic gradients on δ15N values (i.e., latitudinal and inshore/offshore) in the whole region, these were primarily influenced by temporal drivers (i.e., annual variability). At a local scale (i.e., in a radius of 100 km around the colony, within the neritic environment), both δ13C and δ15N values were very influenced by temporal drivers, suggesting that wide-ranging top consumers are hard to trace locally. This study shows that the δ13C values of marine top consumers are good indicators of the foraging habitat at a regional scale in the mid-North Atlantic, especially in terms of inshore/offshore gradients and areas of higher productivity

Habitat and trophic ecology of Southern Ocean cephalopods from stable isotope analyses

Although cephalopods play a critical role in marine food webs both as predators and prey, there is a limited knowledge of several basic aspects of their ecology, including their habitat and trophic level, in the Southern Ocean. We examined the ecological role of several Southern Ocean cephalopod species by analyzing δ13C and δ15N values in lower cephalopod beaks obtained from diet samples of wandering albatross Diomedea exulans from South Georgia (Atlantic Ocean), and from Crozet and Kerguelen Islands (Indian Ocean). Beak δ13C values ranged from -25.7 to -17.9‰, and were used to assign different cephalopod species to the subtropical, sub-Antarctic or Antarctic Zones. Beak δ15N values were more variable among species, ranging from 2.4 to 13.3‰, a difference of ~11‰ that represents approx. 3 trophic levels. Differences among islands in isotope ratios in the same cephalopod species (higher δ15N and lower δ13C values in South Georgia) were attributed to regional oceanographic processes. Antarctic cephalopods occupy niches similar to those found in some pelagic fish, seabirds and marine mammals. As cephalopods are key components in Southern Ocean food webs, these results greatly advance our understanding of the structure, energy and carbon flows in this polar ecosystem

Sexual and individual foraging segregation in Gentoo penguins Pygoscelis papua from the Southern Ocean during an abnormal winter

Knowledge about sexual segregation and gender-specific, or indeed individual specialization, in marine organisms has improved considerably in the past decade. In this context, we tested the “Intersexual Competition Hypothesis” for penguins by investigating the feeding ecology of Gentoo penguins during their austral winter non-breeding season. We considered this during unusual environmental conditions (i.e. the year 2009 had observations of high sea surface and air temperatures) in comparison with the long term average at Bird Island, South Georgia. Through conventional (i.e. stomach contents) and stable isotopic values from red blood cells, plasma and feathers of both male and female Gentoo penguins, we showed that there were significant differences between sexes, with males feeding mainly on fish (54% by mass) followed by crustaceans (38%) whereas females fed mainly on crustaceans (89% by mass) followed by fish (4%). Themisto gaudichaudii was the most important crustacean prey for males (64% by mass; 82% by number; 53% by frequency of occurrence) and females (63% by mass; 77% by number; 89% by frequency of occurrence), contrasting with all previous studies that found Antarctic krill Euphausia superba were generally the main prey. Stable isotopic data showed that, in terms of habitat use (based on δ 13C), there were significant differences in short-term carbon signatures between males and females (based on plasma and red blood cells), suggesting that both sexes explored different habitats, with females exploring more offshore pelagic waters and males feeding more in coastal benthic waters. Based on δ 15N, males fed on significantly higher trophic level than females (based on plasma and red blood cells), in agreement with our diet results., Thus, Gentoo penguins behave in a similar manner to other non-breeding penguins species (e.g. king, macaroni and rockhopper penguins), albeit at a smaller spatial scale (as they do not disperse as these other penguins do), in that they have a wider habitat and trophic niche during the Antarctic Winter (in comparison to Summer). We also detected individual specialization in feeding/trophic levels for each gender, with certain males feeding mainly on fish and certain females mainly on crustaceans, which may be driven the prevailing environmental conditions that lead individuals to search for alternative prey, and cause sexual diet segregation. Our results provide further information to help improve understanding about sexual segregation and individual specialization of marine organisms, while contributing valuable information on the winter diet for Antarctic monitoring programs and for modelling Antarctic marine food webs

Dynamics of a Dual SARS-CoV-2 Lineage Co-Infection on a Prolonged Viral Shedding COVID-19 Case: Insights into Clinical Severity and Disease Duration

A few molecularly proven severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases of symptomatic reinfection are currently known worldwide, with a resolved first infection followed by a second infection after a 48 to 142-day intervening period. We report a multiple-component study of a clinically severe and prolonged viral shedding coronavirus disease 2019 (COVID-19) case in a 17-year-old Portuguese female. She had two hospitalizations, a total of 19 RT-PCR tests, mostly positive, and criteria for releasing from home isolation at the end of 97 days. The viral genome was sequenced in seven serial samples and in the diagnostic sample from her infected mother. A human genome-wide array (>900 K) was screened on the seven samples, and in vitro culture was conducted on isolates from three late samples. The patient had co-infection by two SARS-CoV-2 lineages, which were affiliated in distinct clades and diverging by six variants. The 20A lineage was absolute at the diagnosis (shared with the patient's mother), but nine days later, the 20B lineage had 3% frequency, and two months later, the 20B lineage had 100% frequency. The 900 K profiles confirmed the identity of the patient in the serial samples, and they allowed us to infer that she had polygenic risk scores for hospitalization and severe respiratory disease within the normal distributions for a Portuguese population cohort. The early-on dynamic co-infection may have contributed to the severity of COVID-19 in this otherwise healthy young patient, and to her prolonged SARS-CoV-2 shedding profile.The authors acknowledge the support of the i3S Scientific Platforms BioSciences Screening and Genomics, members of the national infrastructure PPBI-Portuguese Platform of Bioimaging (PPBI-POCI-01-0145-FEDER-022122), PT-OPENSCREEN, GenomePT project (POCI-01-0145-FEDER-022184)

Cephalopods in the diet of nonbreeding black-browed and grey-headed albatrosses from South Georgia

The food and feeding ecology of albatrosses during the nonbreeding season is still poorly known, particularly with regard to the cephalopod component. This was studied in black-browed Thalassarche melanophris and grey-headed T. chrysostoma albatrosses by analysing boluses collected shortly after adults returned to colonies at Bird Island, South Georgia (54°S, 38°W), in 2009. Based on stable isotopic analyses of the lower beaks, we determined the habitat and trophic level (from δ13C and δ15N, respectively) of the most important cephalopods and assessed the relative importance of scavenging in terms of the albatrosses’ feeding regimes. Based on lower rostral lengths (LRLs), the main cephalopod species in the diets of both albatrosses was Kondakovia longimana, by frequency of occurrence (F > 90 %), number (N > 40 %) and mass (M > 80 %). The large estimated mass of many squid, including K. longimana, suggests that a high proportion (>80 % by mass) was scavenged, and that scavenging is much more important during the nonbreeding season than would be expected from breeding-season diets. The diversity of cephalopods consumed by nonbreeding birds in our study was similar to that recorded during previous breeding seasons, but included two new species [Moroteuthis sp. B (Imber) and ?Mastigoteuthis A (Clarke)]. Based on similarities in LRL, δ13C and δ15N, the squid consumed may have been from the same oceanic populations or region, with the exception of Taonius sp. B (Voss) and K. longimana, which, based on significant differences in δ15N values, suggest that they may have originated from different stocks, indicating differences in the albatrosses’ feeding regimes

Show your beaks and we tell you what you eat: Different ecology in sympatric Antarctic benthic octopods under a climate change context

Sympatry can lead to higher competition under climate change and other environmental pressures, including in South Georgia, Antarctica, where the two most common octopod species, Adelieledone polymorpha and Pareledone turqueti, occur side by side. Since cephalopods are typically elusive animals, the ecology of both species is poorly known. As beaks of cephalopods are recurrently found in top predator's stomachs, we studied the feeding ecology of both octopods through the evaluation of niche overlapping and specific beak adaptations that both species present. A multidisciplinary approach combining carbon (δ13C) and nitrogen (δ15N) stable isotope signatures, mercury (Hg) analysis and biomaterials' engineering techniques was applied to investigate the beaks. An isotopic niche overlap of 95.6% was recorded for the juvenile stages of both octopod species, dropping to 19.2% for the adult stages. Both A. polymorpha and P. turqueti inhabit benthic ecosystems around South Georgia throughout their lifecycles (δ13C: −19.21 ± 1.87‰, mean ± SD for both species) but explore trophic niches partially different during adult life stages (δ15N: 7.01 ± 0.40‰, in A. polymorpha, and 7.84 ± 0.65‰, in P. turqueti). The beaks of A. polymorpha are less dense and significantly less stiff than in P. turqueti. Beaks showed lower mercury concentration relative to muscle (A. polymorpha - beaks: 0.052 ± 0.009  μg g−1, muscle: 0.322 ± 0.088  μg g−1; P. turqueti - beaks: 0.038 ± 0.009  μg g−1; muscle: 0.434 ± 0.128  μg g−1). Overall, both octopods exhibit similar habitats but different trophic niches, related to morphology/function of beaks. The high Hg concentrations in both octopods can have negative consequences on their top predators and may increase under the present climate change context.British Antarctic Survey for assisting in the collection of the specimens for this work. Many thanks to 3B's Research Group (University of Minho) and MAREFOZ who were responsible for analysing the physical properties of beaks and stable isotope signatures. A special thank you to our colleague José Queirós from MARE-UC (Coimbra, Portugal) for his suggestions and guidance. A debt of gratitude is also owed to Dr. A. Louise Allcock (NUI Galway) for her useful guidelines. This work is an international effort under the Scientific Committee on Antarctic Research (SCAR) associated programs, expert and action groups, namely SCAR AnT-ERA, SCAR EGBAMM and ICED. J.C. Xavier was supported by the Investigator Programme (IF/00616/2013) of the Foundation for Science and Technology (FCT-Portugal) and PROPOLAR, and F.R. Ceia was supported by a postdoctoral fellowship (SFRH/BPD/95372/2013) attributed by FCT-Portugal and the European Social Fund (POPH, EU). This study benefited from the strategic program of MARE, financed by FCT-Portugal (MARE- UID/MAR/04292/2019). We also acknowledge FCT-Portugal through a PhD grant to J. Seco (SRFH/PD/BD/113487