Spectroscopic direct detection of reflected light from extra-solar planets

At optical wavelengths, an exoplanet's signature is essentially reflected light from the host star - several orders of magnitude fainter. Since it is superimposed on the star spectrum its detection has been a difficult observational challenge. However, the development of a new generation of instruments like ESPRESSO and next generation telescopes like the E-ELT put us in a privileged position to detect these planets' reflected light as we will have access to extremely high signal-to-noise ratio spectra. With this work, we propose an alternative approach for the direct detection of the reflected light of an exoplanet. We simulated observations with ESPRESSO@VLT and HIRES@E-ELT of several star+planet systems, encompassing 10h of the most favourable orbital phases. To the simulated spectra we applied the Cross Correlation Function to operate in a much higher signal-to-noise ratio domain than when compared with the spectra. The use of the Cross-Correlation Function permitted us to recover the simulated the planet signals at a level above 3 \sigma_{noise} significance on several prototypical (e.g., Neptune type planet with a 2 days orbit with the VLT at 4.4 \sigma_{noise} significance) and real planetary systems (e.g., 55 Cnc e with the E-ELT at 4.9 \sigma_{noise} significance). Even by using a more pessimistic approach to the noise level estimation, where systematics in the spectra increase the noise 2-3 times, the detection of the reflected light from large close-orbit planets is possible. We have also shown that this kind of study is currently within reach of current instruments and telescopes (e.g., 51 Peg b with the VLT at 5.2 \sigma_{noise} significance), although at the limit of their capabilities.Comment: Accepted for Publication on MNRAS: 2013 August 29; Online Article: http://mnras.oxfordjournals.org/content/early/2013/09/27/mnras.stt1642; 5 Figures, 11 page

The know and unknow of social facilitation on stereotyping

Tese apresentada para cumprimento dos requisitos necessários à obtenção do grau Doutor em Psicologia na área de especialização de Psicologia Social apresentada no ISPA-Instituto Universitário no ano de 2020.Since Triplett (1898), that experimental psychology has explored how the presence of others (vs being alone) affects our behavior and mind. This effect is nowadays known as Social Facilitation. Although, many advances have been made in this area, little is known about how Social Facilitation affects stereotyping. As such, this thesis investigates how the presence of other persons (vs being alone) affects our stereotyping and its mechanisms. Until the present date, only two papers have addressed this theme reaching opposite conclusions. While Lambert, et al. (2003) suggest more stereotyping in the presence of others, Castelli and Tomelleri (2008) suggest less stereotyping in the presence of others. To approach this incongruency in the literature, we conceptually replicated the main experiment of each of these papers. Our results did not replicate any of those papers. We did not find a clear Social Facilitation effect over stereotyping when following Lambert, et al’s. (2003) methodology. Moreover, when replicating Castelli and Tomelleri (2008), we found evidence of a Social Facilitation effect over stereotyping, but now in the opposite direction of the original study, showing more stereotyping in presence of others. Throughout this thesis, we developed studies and carefully analyzed the results aiming for better understanding the effects. Since data suggested that the evidence could be spread over reaction times (RTs) or error rates, we analyzed our data (and data from a new experiment) by using the Diffusion Model. This technique allows assembling RTs and accuracy data into a set of parameters. This analysis was highly fruitful adding relevant information for future empirical approaches to stereotyping effects in the presence and isolation from others. First, Social Facilitation effects over stereotyping occur, because those in presence of others have higher stereotyping than those in isolation. Second, as already stated in the Social Facilitation literature, the type of Social Condition matters. Because we operationalized social presence as co-action and isolation having no presence of the experimenter, results diverge from the original studies. Third, Social Facilitation effects over stereotyping depend on the type the task used to measure stereotyping. These effects were more subtle in the Weapon Identification Task (WIT; Payne, 2001) and clearer in the race Implicit Association Task (IAT; Greenwald, McGhee & Schwartz, 1998). We argue that this occurs because Social Facilitation effects occur through a mechanism that is differently represented in those tasks. Fourth, our isolation condition challenges the typical results obtained in the WIT. As such our data is interpreted as evidence that different social conditions can lead people to cope differently with this task. Moreover, our data in general shows evidence of more stereotype bias and less control over stereotype activation in presence of others. We interpret this data as corroborating evidence of previous claims that the presence of others creates an overload context (Baron, 1986) and that it somehow reduces our capability of exerting an efficient control mechanism (Wagstaff, et al., 2008).Desde Triplett (1898) que a psicologia experimental tem vindo a explorar de que forma a presença de outros (em contraste com estar sozinho) afeta o nosso comportamento e mente. Este efeito é atualmente conhecido como Facilitação Social. Embora muitos avanços tenham sido feitos nesta área, pouco é conhecido sobre de que forma a Facilitação Social afeta a estereotipização (uso dos estereótipos) e os seus mecanismos. Até à data apenas dois artigos abordaram esta temática, sendo que estes apresentam conclusões opostas. Enquanto Lambert et al. (2003) sugerem mais estereotipização na presença de outros, Castelli e Tomelleri (2008) sugerem menos estereotipização na presença de outros. De forma a abordar esta incongruência na literatura, replicamos conceptualmente a experiência principal de cada um dos artigos. Os nossos resultados não replicaram nenhuma das conclusões dos artigos originais. Não encontrámos um efeito de Facilitação Social claro sobre a estereotipização quando seguimos a metodologia de Lambert et al. (2003). Já com a replicação de Castelli e Tomelleri (2008) encontrámos evidência de Facilitação Social sobre estereotipização, mas na direção oposta da apresentada no artigo original, ou seja, maior estereotipização na presença de outros. Ao longo desta tese foram desenvolvidos estudos e analisados resultados de forma cuidadosa com o objetivo de se obter uma melhor compreensão sobre os efeitos em estudo. Já que os dados sugeriram que os efeitos em estudo poderiam se estar a propagar pelos tempos de reação e taxas de erro, analisámos os nossos dados (e os dados de uma nova experiência) através do Modelo de Difusão. Esta técnica permite juntar tempos de reação e taxas de acerto/erro no conjunto de parâmetros. Esta análise permitiu alcançar informação relevante para futuros estudos que abordam os efeitos de estereotipização como também os efeitos da presença ou isolamento de outros. Em primeiro lugar, foram detetados efeitos de Facilitação Social sobre estereotipização, visto que a estereotipização foi maior na presença de outros no que no isolamento. Em segundo lugar, confirmamos que os tipos de condições sociais são relevantes para o efeito, uma vez que a nossa operacionalização (co-ação versus isolamento-sem a presença do experimentador), originou resultados divergentes dos estudos originais. Em terceiro lugar, verificou-se que os efeitos de Facilitação Social sobre a estereotipização dependem do tipo de tarefa usada para medir a estereotipização. Estes efeitos foram mais subtis na Weapon Identification Task (WIT; Payne, 2001) e mais claros na Implicit Association Task (IAT; Greenwald,McGhee & Schwartz, 1998). Nós argumentamos que isto ocorre porque os efeitos de Facilitação Social ocorrem através de mecanismos que são representados de forma diferente em cada uma das tarefas. Em quarto lugar, a nossa condição de isolamento desafia os resultados que são tipicamente obtidos na WIT. Desta forma, os nossos dados são interpretados como evidência que diferentes condições sociais podem levar as pessoas a lidarem com a tarefa de forma diferente. Além disso, os nossos dados de forma geral evidenciam mais viés estereotípico e menos controlo sobre a ativação do estereótipo na presença de outros. Interpretamos estes dados como estando a corroborar os estudos anteriores que enfatizam a presença de outros como um contexto que cria sobrecarga cognitiva (Baron, 1986) e que de alguma forma reduz a capacidade de usar mecanismos de controlo de forma eficiente (Wagstaff, et al., 2008)

The practice of valuation for M&As and the role of advisors

This study explores the valuation accuracy of three of the most commonly used models in valuation by financial advisors in a takeover context: the discounted cash flow (DCF), the method of comparable companies and the method of comparable transactions. The motivation for this work is the lack of literature on the topic which motivated an exploratory approach to the issue. The thesis investigates the answer the following research questions: (1) How accurate are the valuation methods? (2) Which valuations method is more reliable? (3) Does the valuation reveals biasness in the valuation taken into consideration the commissioner to whom the financial advisor is reporting to? The hypotheses are tested using a sample of 110 deals that took place in the United States of America and were reported to the Securities Exchange Commission of the same country. The results demonstrate that the expertise advocated by financial advisors is crucial to shrink the range of the valuations. Moreover, the evidence suggests that there seems to be a trade-off between valuation accuracy and range, where DCF method has the largest standard deviation and provides the closest valuation to the acquisition price

Exploring a volatomic-based strategy for a fingerprinting approach of Vaccinium padifolium L. berries at different ripening stages

The effect of ripening on the evolution of the volatomic pattern from endemic Vaccinium padifolium L. (Uveira) berries was investigated using headspace-solid phase microextraction (HS-SPME) followed by gas chromato graphy/quadrupole-mass spectrometry (GC–qMS) and multivariate statistical analysis (MVA). The most sig nificant HS-SPME parameters, namely fibre polymer, ionic strength and extraction time, were optimized in order to improve extraction efficiency. Under optimal experimental conditions (DVB/CAR/PDMS fibre coating, 40 °C, 30 min extraction time and 5 g of sample amount), a total of 72 volatiles of different functionalities were isolated and identified. Terpenes followed by higher alcohols and esters were the predominant classes in the ripening stages – green, break and ripe. Although significant differences in the volatomic profiles at the three stages were obtained, cis-β-ocimene (2.0–40.0%), trans-2-hexenol (2.4–19.4%), cis-3-hexenol (2.5.16.4%), β-myrcene (1.9–13.8%), 1-hexanol (1.7–13.6%), 2-hexenal (0.7–8.0%), 2-heptanone (0.7–7.7%), and linalool (1.9–6.1%) were the main volatile compounds identified. Higher alcohols, carboxylic acids and ketones gradually increased during ripening, whereas monoterpenes significantly decreased. These trends were dominated by the higher alcohols (1-hexanol, cis-3-hexenol, trans-2-hexenol) and monoterpenes (β-myrcene, cis-β-ocimene and trans-β ocimene). Partial least squares regression (PLSR) revealed that ethyl caprylate (1.000), trans-geraniol (0.995), ethyl isovalerate (−0.994) and benzyl carbinol (0.993) are the key variables that most contributed to the successful differentiation of Uveira berries according to ripening stage. To the best of our knowledge, no study has carried out on the volatomic composition of berries from endemic Uveira.info:eu-repo/semantics/publishedVersio

Optical and Near-Infrared Radial Velocity Content of M Dwarfs: Testing Models with Barnard's Star

High precision radial velocity (RV) measurements have been central in the study of exoplanets during the last two decades, from the early discovery of hot Jupiters, to the recent mass measurements of Earth-sized planets uncovered by transit surveys. While optical radial-velocity is now a mature field, there is currently a strong effort to push the technique into the near-infrared (nIR) domain (chiefly $Y$, $J$, $H$ and $K$ band passes) to probe planetary systems around late-type stars. The combined lower mass and luminosity of M dwarfs leads to an increased reflex RV signal for planets in the habitable zone compared to Sun-like stars. The estimates on the detectability of planets rely on various instrumental characteristics, but also on a prior knowledge of the stellar spectrum. While the overall properties of M dwarf spectra have been extensively tested against observations, the same is not true for their detailed line profiles, which leads to significant uncertainties when converting a given signal-to-noise ratio to a corresponding RV precision as attainable on a given spectrograph. By combining archival CRIRES and HARPS data with ESPaDOnS data of Barnard's star, we show that state-of-the-art atmosphere models over-predict the $Y$ and $J$-band RV content by more than a factor of $\sim$$2$, while under-predicting the $H$ and $K$-band content by half.Comment: accepted for publication in A

As imagens do envelhecimento e as práticas idadistas em cuidados de saúde primários: implicações na actividade física dos idosos

El envejecimiento de la población ha ido en aumento en todo el mundo. A pesar de la importancia de la actividad física en la salud, parece que muchas personas mayores son sedentarias. Los profesionales sanitarios pueden estar influidos por las imágenes negativas relacionadas con el envejecimiento. Esto puede dar lugar a prácticas discriminatorias con repercusiones en la actividad física de las personas mayores. Este estudio tiene como objetivo examinar cómo las imágenes de las prácticas de envejecimiento e ideas percibidas por los ancianos en contacto con profesionales de la salud influyen en su actividad física. Se realizó un estudio cualitativo, utilizando la entrevista semiestructurada y la asociación libre de palabras, siendo entrevistados 18 usuarios de un centro de salud. A partir de los resultados, se encontró que aproximadamente la mitad de los participantes (n = 8) menciona que la forma en cómo son vistos por los profesionales de la salud y cómo se ocupan de ellos influye en su actividad física. La imagen que más favorece esta práctica era la de considerar a las personas con la voluntad de vivir. La imagen más mencionado como un obstáculo para la actividad física era de ser: mayor deprimido / triste / aburrido y de mal humor / terco. La práctica que más a menudo se identifica con la dificultad para la actividad física era la falta de interés respecto a los problemas de salud.The aging population has been increasing around the world. Despite the importance of physical activity on health, it appears that a large proportion of elderly are sedentary. Health professionals may be influenced by negative images related to aging and that may lead to discriminatory practices, with repercussions on the physical activity of the elderly. This study aims to examine how the images concerning aging and older people, as well as ageist practices perceived by older people in contact with health professionals, do influence their physical activity. A qualitative study was conducted using a semi-structured interview and techniques of free word association. Eighteen primary care elderly users were interviewed. A considerable proportion of the sample (n=8) mentioned that the way health professionals see them and deal with them influences their level of physical activity. The image that most favoured this practice was that people are willing to live. Counseling/health education was identified as the main favouring practice. The image which was most often mentioned as hindering physical activity was that of elderly as being depressed, sad or bored, and grumpy or stubborn. The practice most often identified as hindering physical activity was lack of interest regarding health problems.O envelhecimento demográfico tem vindo a aumentar em todo o mundo. Apesar da importância da actividade física na saúde, verifica-se que muitos idosos são sedentários. Os profissionais de saúde podem ser influenciados por imagens negativas relativas ao envelhecimento. Tal pode conduzir a práticas de discriminação, com repercussão na actividade física dos idosos. Este estudo tem como objectivo analisar o modo como as imagens do envelhecimento e as práticas idadistas percebidas pelos idosos no contacto com profissionais de saúde influenciam a sua actividade física. Realizou-se um estudo qualitativo, com recurso à entrevista semi-estruturada e de associação livre das palavras, sendo entrevistados 18 utentes de um Centro de Saúde. Pelos resultados, constatou-se que cerca de metade dos participantes (n=8) mencionou que a forma como são vistos pelos profissionais de saúde e como estes lidam consigo influencia a sua actividade física. A imagem mais referida como favorecendo esta prática foi o facto de se considerarem pessoas com vontade de viver. Como principal prática favorecedora identificou-se o aconselhamento para a saúde. A imagem mais mencionada como dificultando a actividade física foi a de os idosos serem deprimidos/tristes/aborrecidos e rabugentos/teimosos. A prática mais identificada como a dificultando foi o desinteresse face aos problemas de saúde.peerReviewe

Musical and cognitive abilities in children from disadvantaged backgrounds

Human beings are born with several abilities which are amenable to change. A growing number of studies have focused on the relations between musical and cognitive abilities but research with children from disadvantaged communities is scarce. This study explored the relations between musical and cognitive abilities in disadvantaged children. Participants were 169 children from deprived neighborhoods, attending the second year of primary education in public schools that do not offer music education. Children’s musical abilities (perception) were measured with the Melody, Rhythm, and Memory tests of Montreal Battery for the Evaluation of Musical Abilities and their cognitive abilities, with five WISC-III subtests (Similarities, Vocabulary, Cubes, Picture Arrangement, and Digits). Parental level of education was obtained from a questionnaire on the socio-economic status of children’s families. Results revealed (1) few and weak correlations between musical and cognitive abilities; (2) stronger correlations of Socioeconomic Status (SES) with cognitive than with musical abilities; (3) digit span predicts all musical abilities; 4) a clear factorial distinction between musical and cognitive abilities. Overall, results suggest that disadvantaged children’s musical and cognitive abilities, as measured by the present instruments, are partly independent regarding processing components.info:eu-repo/semantics/publishedVersio