Signal processing of physiological signals for automated assessment of stress in computer users

The need to provide computers with the ability to distinguish the affective state of their users is a major requirement for the practical implementation of affective computing concepts. This dissertation proposes the application of signal processing methods on physiological signals to extract from them features that can be processed by learning pattern recognition systems to provide cues about a person's affective state. In particular, combining physiological information sensed from a user's left hand in a non-invasive way with the pupil diameter information from an eye-tracking system may provide a computer with an awareness of its user's affective responses in the course of human-computer interactions. In this study an integrated hardware-software setup was developed to achieve automatic assessment of the affective status of a computer user. A computer-based "Paced Stroop Test" was designed as a stimulus to elicit emotional stress in the subject during the experiment. Four signals: the Galvanic Skin Response (GSR), the Blood Volume Pulse (BVP), the Skin Temperature (ST) and the Pupil Diameter (PD), were monitored and analyzed to differentiate affective states in the user. Several signal processing techniques were applied on the collected signals to extract their most relevant features. These features were analyzed with learning classification systems, to accomplish the affective state identification. Three learning algorithms: Naïve Bayes, Decision Tree and Support Vector Machine were applied to this identification process and their levels of classification accuracy were compared. The results achieved indicate that the physiological signals monitored do, in fact, have a strong correlation with the changes in the emotional states of the experimental subjects. These results also revealed that the inclusion of pupil diameter information significantly improved the performance of the emotion recognition system. ^

Visual driver support system for traffic signs

It has been well documented that traffic accidents that can be avoided occur when the motorists miss or ignore traffic signs. With the attention of drivers getting diverted due to distractions like cell phone conversations, missing traffic signs has become more prevalent. Also, poor weather and other unfriendly driving conditions sometimes makes the motorists not to be alert all the time and see every traffic sign on the road. Besides, most cars do not have any form of traffic assistance. Because of heavy traffic and proliferation of traffic signs on the roads, there is a need for a system that assists the driver not to miss a traffic sign to reduce the probability of an accident. Since visual information is critical for driving, processed video signals from cameras have been chosen to assist drivers. These inexpensive cameras can be easily mounted on the automobile. The objective of the present investigation and the traffic system development is to recognize the traffic signs electronically and alert drivers. For the case study and the system development, five important and critical traffic signs have been selected. They are: STOP, NO ENTER, NO RIGHT TURN, NO LEFT TURN, and YIELD. The system was evaluated processing still pictures taken from the public roads, and the recognition results were presented in an analysis table to indicate the correct identifications and the false ones. The system reached the acceptable recognition rate of 80% for all five traffic signs. The processing rate was about three seconds. The capabilities of MATLAB, VLSI design platforms and coding have been used to generate a visual warning to complement the visual driver support system with a Field Programmable Gate Array (FPGA) on a XUP Virtex-II Pro Development System.

Space time coding for polynomial phase modulated signals

Polynomial phase modulated (PPM) signals have been shown to provide improved error rate performance with respect to conventional modulation formats under additive white Gaussian noise and fading channels in single-input single-output (SISO) communication systems. In this dissertation, systems with two and four transmit antennas using PPM signals were presented. In both cases we employed full-rate space-time block codes in order to take advantage of the multipath channel. For two transmit antennas, we used the orthogonal space-time block code (OSTBC) proposed by Alamouti and performed symbol-wise decoding by estimating the phase coefficients of the PPM signal using three different methods: maximum-likelihood (ML), sub-optimal ML (S-ML) and the high-order ambiguity function (HAF). In the case of four transmit antennas, we used the full-rate quasi-OSTBC (QOSTBC) proposed by Jafarkhani. However, in order to ensure the best error rate performance, PPM signals were selected such as to maximize the QOSTBC’s minimum coding gain distance (CGD). Since this method does not always provide a unique solution, an additional criterion known as maximum channel interference coefficient (CIC) was proposed. Through Monte Carlo simulations it was shown that by using QOSTBCs along with the properly selected PPM constellations based on the CGD and CIC criteria, full diversity in flat fading channels and thus, low BER at high signal-to-noise ratios (SNR) can be ensured. Lastly, the performance of symbol-wise decoding for QOSTBCs was evaluated. In this case a quasi zero-forcing method was used to decouple the received signal and it was shown that although this technique reduces the decoding complexity of the system, there is a penalty to be paid in terms of error rate performance at high SNRs.

Endocrine regulation of dynamic communication signals in gymnotiform fish

Communication signals are shaped by the opposing selection pressures imposed by predators and mates. A dynamic signal might serve as an adaptive compromise between an inconspicuous signal that evades predators and an extravagant signal preferred by females. Such a signal has been described in the gymnotiform electric fish, Brachyhypopomus gauderio, which produces a sexually dimorphic electric organ discharge (EOD). The EOD varies on a circadian rhythm and in response to social cues. This signal plasticity is mediated by the slow action of androgens and rapid action of melanocortins. My dissertation research tested the hypotheses that (1) signal plasticity is related to sociality levels in gymnotiform species, and (2) differences in signal plasticity are regulated by differential sensitivity to androgen and melanocortin hormones. To assess the breadth of dynamic signaling within the order Gymnotiformes, I sampled 13 species from the five gymnotiform families. I recorded EODs to observe spontaneous signal oscillations after which I injected melanocortin hormones, saline control, or presented the fish with a conspecific. I showed that through the co-option of the ancient melanocortin pathway, gymnotiforms dynamically regulate EOD amplitude, spectral frequency, both, or neither. To investigate whether observed EOD plasticities are related to species-specific sociality I tested four species; two territorial, highly aggressive species, Gymnotus carapo and Apteronotus leptorhynchus, a highly gregarious species, Eigenmannia cf. virescens , and an intermediate short-lived species with a fluid social system, Brachyhypopomus gauderio. I examined the relationship between the androgens testosterone and 11-ketotestosterone, the melanocortin α-MSH, and their roles in regulating EOD waveform. I implanted all fish with androgen and blank silicone implants, and injected with α-MSH before and at the peak of implant effect. I found that waveforms of the most territorial and aggressive species were insensitive to hormone treatments; maintaining a static, stereotyped signal that preserves encoding of individual identity. Species with a fluid social system were most responsive to hormone treatments, exhibiting signals that reflect immediate condition and reproductive state. In conclusion, variation in gymnotiform signal plasticity is hormonally regulated and seems to reflect species-specific sociality.

Transcriptome Analysis Reveals New Insights into the Modulation of Endometrial Stromal Cell Receptive Phenotype by Embryo-Derived Signals Interleukin-1 and Human Chorionic Gonadotropin: Possible Involvement in Early Embryo Implantation

The presence of the conceptus in uterine cavity necessitates an elaborate network of interactions between the implanting embryo and a receptive endometrial tissue. We believe that embryo-derived signals play an important role in the remodeling and the extension of endometrial receptivity period. Our previous studies provided original evidence that human Chorionic Gonadotropin (hCG) modulates and potentiates endometrial epithelial as well as stromal cell responsiveness to interleukin 1 (IL1), one of the earliest embryonic signals, which may represent a novel pathway by which the embryo favors its own implantation and growth within the maternal endometrial host. The present study was designed to gain a broader understanding of hCG impact on the modulation of endometrial cell receptivity, and in particular, cell responsiveness to IL1 and the acquisition of growth-promoting phenotype capable of receiving, sustaining, and promoting early and crucial steps of embryonic development. Our results showed significant changes in the expression of genes involved in cell proliferation, immune modulation, tissue remodeling, apoptotic and angiogenic processes. This points to a relevant impact of these embryonic signals on the receptivity of the maternal endometrium, its adaptation to the implanting embryo and the creation of an environment that is favorable for the implantation and the growth of this latter within a new and likely hostile host tissue. Interestingly our data further identified a complex interaction between IL1 and hCG, which, despite a synergistic action on several significant endometrial target genes, may encompass a tight control of endogenous IL1 and extends to other IL1 family members.

Post-revolutionary post-modernism: Central American detective fiction by the turn of the 21st century

Contemporary Central American fiction has become a vital project of revision of the tragic events and the social conditions in the recent history of the countries from which they emerge. The literary projects of Sergio Ramirez (Nicaragua), Dante Liano (Guatemala), Horacio Castellanos Moya (El Salvador), and Ramon Fonseca Mora (Panama), are representative of the latest trends in Central American narrative. These trends conform to a new literary paradigm that consists of an amalgam of styles and discourses, which combine the testimonial, the historical, and the political with the mystery and suspense of noir thrillers. Contemporary Central American noir narrative depicts the persistent war against social injustice, violence, criminal activities, as well as the new technological advances and economic challenges of the post-war neo-liberal order that still prevails throughout the region. ^ Drawing on postmodernism theory proposed by Ihab Hassan, Linda Hutcheon and Brian MacHale, I argued that the new Central American literary paradigm exemplified by Sergio Ramirez's El cielo llora por mí, Dante Liano's El hombre de Montserrat, Horacio Castellanos Moya's El arma en el hombre and La diabla en el espejo , and Ramon Fonseca Mora's El desenterrador, are highly structured novels that display the characteristic marks of postmodern cultural expression through their ambivalence, which results from the coexistence of multiple styles and conflicting ideologies and narrative trends. The novels analyzed in this dissertation make use of a noir sensitivity in which corruption, decay and disillusionment are at their core to portray the events that shaped the modern history of the countries from which they emerge. The revolutionary armed struggle, the state of terror imposed by military regimes and the fight against drug trafficking and organized crime, are among the major themes of these contemporary works of fiction, which I have categorized as perfect examples of the post-revolutionary post-modernism Central American detective fiction at the turn of the 21st century.^

Why Most Biomedical Findings Echoed by Newspapers Turn Out to be False: The Case of Attention Deficit Hyperactivity Disorder

Context: Because positive biomedical observations are more often published than those reporting no effect, initial observations are often refuted or attenuated by subsequent studies. Objective: To determine whether newspapers preferentially report on initial findings and whether they also report on subsequent studies. Methods: We focused on attention deficit hyperactivity disorder (ADHD). Using Factiva and PubMed databases, we identified 47 scientific publications on ADHD published in the 1990s and soon echoed by 347 newspapers articles. We selected the ten most echoed publications and collected all their relevant subsequent studies until 2011. We checked whether findings reported in each ‘‘top 10’’ publication were consistent with previous and subsequent observations. We also compared the newspaper coverage of the ‘‘top 10’’ publications to that of their related scientific studies. Results: Seven of the ‘‘top 10’’ publications were initial studies and the conclusions in six of them were either refuted or strongly attenuated subsequently. The seventh was not confirmed or refuted, but its main conclusion appears unlikely. Among the three ‘‘top 10’’ that were not initial studies, two were confirmed subsequently and the third was attenuated. The newspaper coverage of the ‘‘top 10’’ publications (223 articles) was much larger than that of the 67 related studies (57 articles). Moreover, only one of the latter newspaper articles reported that the corresponding ‘‘top 10’’ finding had been attenuated. The average impact factor of the scientific journals publishing studies echoed by newspapers (17.1 n = 56) was higher (p,0.0001) than that corresponding to related publications that were not echoed (6.4 n = 56). Conclusion: Because newspapers preferentially echo initial ADHD findings appearing in prominent journals, they report on uncertain findings that are often refuted or attenuated by subsequent studies. If this media reporting bias generalizes to health sciences, it represents a major cause of distortion in health science communication.

Paleoenvironments and geochemical signals from the late Barremian to the middle Aptian in a Tethyan marginal basin, northeast Spain: Implications for carbon sequestration in restricted basins

The hallmark of oceanic anoxic event 1a (OAE1a) (early Aptian ~125 Ma) corresponds to worldwide deposition of black shales with total organic carbon (TOC) content > 2% and a δ13C positive excursion up to ~5‰. OAE1a has been related to large igneous province volcanism and dissociation of methane hydrates during the Lower Cretaceous. However, the occurrence of atypical, coeval and diachronous organic-rich deposits associated with OAE1a, which are also characterized by positive spikes of the δ 13C in epicontinental to restricted marine environments of the Tethys Ocean, indicates localized responses decoupled from complex global forcing factors. ^ The present research is a high-resolution, multiproxy approach to assess the paleoenvironmental conditions that led to enhanced carbon sequestration from the late Barremian to the middle Aptian in a restricted, Tethyan marginal basin prior to and during OAE1a. I studied the lower 240 m of the El Pui section, Organyà Basin, Spanish Pyrenees. The basin developed as the result of extensional tectonism linked to the opening of the Atlantic Ocean. At the field scale the section consists of a sequence of alternating beds of cm – m-scale, medium-gray to grayish-black limestones and marlstones with TOC up to ~4%. ^ The results indicate that the lowest 85 m of the section, from latest Barremian -earliest Aptian, characterize a deepening phase of the basin concomitant with sustained riverine flux and intensified primary productivity. These changes induced a shift in the sedimentation pattern and decreased the oxygen levels in the water column through organic matter respiration and limited ventilation of the basin. ^ The upper 155 m comprising the earliest – late-early Aptian document the occurrence of OAE1a and its associated geochemical signatures (TOC up to 3% and a positive shift in δ13C of ~5‰). However, a low enrichment of redox-sensitive trace elements indicates that the basin did not achieve anoxic conditions. The results also suggest that a shallower-phase of the basin, coeval with platform progradation, may have increased ventilation of the basin at the same time that heightened sedimentation rates and additional input of organic matter from terrestrial sources increased the burial and preservation rate of TOC in the sediment.^

Corpus annotation of causal relations and their signals in English and Spanish

El estudio de las relaciones causales y su expresión lingüística ha sido comúnmente estudiado desde diferentes perspectivas en los años recientes. Sin embargo, pocos estudios han intentado combinar diferentes enfoques para establecer el significado de estas relaciones, y han investigado de manera contrastiva las señales usadas para expresarlas. Este trabajo de fin de master es un proyecto para avanzar el conocimiento en este área mediante la investigación de: a) la posibilidad de caracterizar las relaciones causales en diferentes tipos, usando características que combinan un enfoque funcional y cognitivo; b) los tipos de relaciones causales preferidas en los textos expositivos en inglés y sus traducciones al español; c) las expresiones lingüísticas preferidas para expresar dichas relaciones causales en los textos originales en inglés y sus traducciones al español. La metodología usada en esta investigación se basa en la anotación manual de un corpus bilingüe compuesto de un total de 37 textos expositivos (incluyendo los textos originales en inglés y sus traducciones al español) extraídos del corpus MULTINOT, un corpus de alta calidad, con registros diversificados y multifuncional bilingüe inglésespañol, actualmente compilado y anotado multidimensionalmente por los miembros del grupo de investigación FUNCAP con el proyecto MULTINOT (véase Lavid et al.2015) El estudio se llevó a cabo en cuatro pasos principales: primero, un esquema de anotación para las relaciones causales en inglés y español fue diseñado constando de tres sistemas interrelacionados y sus correspondientes características; tras ello, se compiló un inventario de señales para las relaciones causales en inglés y español, y una categorización en diferentes tipos; seguidamente, el esquema de anotación fue implementado en la herramienta UAM Corpus Tool y el conjunto de textos bilingües fue anotado por el autor de este estudio; finalmente, los datos extraídos de la anotación fueron analizados estadísticamente para comprobar las posibles diferencias entre los textos originales en inglés y sus traducciones al español respecto a la selección del tipo de relación de causa y sus señales. El análisis estadístico de los datos anotados sugiere que los tipos de relaciones de causa preferidos en los textos originales en inglés y son los tipos de contenido y no volitivos, que el orden de aparición de estos tipos de señales preferido es la segunda posición, y las señales más recurrentes usadas para expresar dichas relaciones son las conjunciones, seguidas de los sintagmas verbales. El análisis de las traducciones al español revela un alto grado de similitud con los datos de los textos originales en inglés, lo que sugiere que en las traducciones al español se conservan las preferencias de los textos originales en la mayoría de los casos y que estas elecciones pueden considerarse un indicativo de los textos expositivos en inglés. Proyectos futuros se centraran en el análisis de los textos originales en español para comprobar si las tendencias observadas en los textos originales en inglés y sus traducciones al español son también validas en textos originales en español, y en la especificación de patrones que puede ayudar al análisis automático de estas relaciones

Regulatory factors controlling muscle mass : competition between innate immune function and anabolic signals in regulation of atrogin-1 in Atlantic salmon

The research was supported by an industrial PhD studentship between University of Aberdeen and by BioMar Ltd., for Z. Heidari.

Regulatory factors controlling muscle mass : competition between innate immune function and anabolic signals in regulation of atrogin-1 in Atlantic salmon

The research was supported by an industrial PhD studentship between University of Aberdeen and by BioMar Ltd., for Z. Heidari.

Beak colour dynamically signals changes in fasting status and parasite loads in king penguins

Peer reviewed

The empirical case against the ‘demographic turn’ in Palaeolithic archaeology

Funding. M.C.’s work is supported by the Social Sciences and Humanities Research of Canada, the Canada Research Chairs Programme, the Canada Foundation for Innovation, the British Columbia Knowledge Development Fund and Simon Fraser University. K.V. received support from the Netherlands Organization for Scientific Research (VIDI-grant 016.144312). R.C. and W.R. are supported by the Australian Research Council (discovery grants nos DP120100580 and DP150100586).

Regulatory factors controlling muscle mass : competition between innate immune function and anabolic signals in regulation of atrogin-1 in Atlantic salmon

The research was supported by an industrial PhD studentship between University of Aberdeen and by BioMar Ltd., for Z. Heidari.

Characterisation of cascaded Raman-assisted fibre optical parametric amplifiers using WDM QPSK signals

We report the first WDM numerical characterisation of crosstalk growth in cascaded Raman-Assisted Fibre Optical Parametric Amplifiers (RA-FOPAs). A cascade of ten RA-FOPAs results in ∼13dB lower crosstalk than the equivalent cascade of conventional FOPAs.