101,208 research outputs found

    Inference Over Bayesian Networks for the Diagnosis and Sensory Enhancement of Mobile Robots

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    The thesis contributes with a novel modeling paradigm, a so-called Bayesian sensory architecture, that enables the representation of any robotic sensory system, allowing the identification of anomalies and the recovery from them. The main drawback of this proposal is the potentially high computational cost of inference with Bayesian networks, which is addressed with a novel, approximate algorithm that leverages the structure of the proposed model. Both the sensory architecture and the corresponding inference algorithm are implemented for different robotic tasks, and are validated through different sets of both simulated and real experiments. One of the implementations is aimed at analyzing the performance of the proposed algorithm in terms of error and computation time. The results obtained from the experiments show that the cost of inference is significantly reduced, and that the approximate queries produced still serve to perform sensory diagnosis and recovery adequately. Another implementation is proposed for the problem of robotic navigation in human environments. In this case, the experimental results prove that the use of the architecture manages to increase the safety and efficiency of navigation. Lastly, a new inference approach based on the use of feedforward neural networks is implemented and tested for this problem, showing that it is possible to reduce, even more, the cost of inference with Bayesian networks, enabling real time operation.Mobile robots are nowadays present in countless real-world applications, aiding or substituting human beings in a wide variety of tasks related to scopes as diverse as industrial, military, medical, educational and many others. The use of mobile platforms in all these contexts is revolutionizing their respective fields, overcoming previous limitations and offering new possibilities. However, for a mobile robot to work properly, it is essential that its sensory apparatus provides correct and reliable information, which is often challenging due to the complexity of the physical world and its uncertain nature. To address that, this thesis explores the possibilities of the application of Bayesian networks (BNs) to the problem of sensory diagnosis and enhancement in the context of mobile robotics. Arised from the realm of artificial intelligence, Bayesian networks constitute a rigorous mathematical framework that enables both the integration of heterogeneous sources of information and the reasoning about them while taking their uncertainty into account. The thesis first analyzes different sensory anomalies in mobile robots and the impact of such abnormal behavior on the performance of these platforms. Given the wide variety of existing sensory devices, the analysis is focused on range sensors, since they are essential to many robotic tasks also grounded on probabilistic frameworks such as Bayesian estimators. Specifically, the thesis contributes with a rigorous statistical study of the influence of abnormal range observations on the performance of Bayesian filters, addressing the problem from a generic perspective thanks to the use of BNs. The conclusions obtained serve to illustrate the importance of sensory abnormalities beyond the pervasively studied issue of noisy observations. The treatment of sensory anomalies in mobile robots with Bayesian networks is then addressed

    Analysis of reliable deployment of TDOA local positioning architectures

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    .Local Positioning Systems (LPS) are supposing an attractive research topic over the last few years. LPS are ad-hoc deployments of wireless sensor networks for particularly adapt to the environment characteristics in harsh environments. Among LPS, those based on temporal measurements stand out for their trade-off among accuracy, robustness and costs. But, regardless the LPS architecture considered, an optimization of the sensor distribution is required for achieving competitive results. Recent studies have shown that under optimized node distributions, time-based LPS cumulate the bigger error bounds due to synchronization errors. Consequently, asynchronous architectures such as Asynchronous Time Difference of Arrival (A-TDOA) have been recently proposed. However, the A-TDOA architecture supposes the concentration of the time measurement in a single clock of a coordinator sensor making this architecture less versatile. In this paper, we present an optimization methodology for overcoming the drawbacks of the A-TDOA architecture in nominal and failure conditions with regards to the synchronous TDOA. Results show that this optimization strategy allows the reduction of the uncertainties in the target location by 79% and 89.5% and the enhancement of the convergence properties by 86% and 33% of the A-TDOA architecture with regards to the TDOA synchronous architecture in two different application scenarios. In addition, maximum convergence points are more easily found in the A-TDOA in both configurations concluding the benefits of this architecture in LPS high-demanded applicationS

    What is the importance of sperm subpopulations?

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    .The study of sperm subpopulations spans three decades. The origin, meaning, and practical significance, however, are less clear. Current technology for assessing sperm morphology (CASA-Morph) and motility (CASA-Mot) has enabled the accurate evaluation of these features, and there are many options for data classification. Subpopulations could occur as a result of the stage of development of each spermatozoon in the subpopulation. Spermatogenesis might contribute to the production of these subpopulations. Insights from evolutionary biology and recent molecular research are indicative of the diversity among male gametes that could occur from unequal sharing of transcripts and other elements through cytoplasmic bridges between spermatids. Sperm cohorts exiting the gonads would contain different RNA and protein contents, affecting the spermatozoon physiology and associations with the surrounding environmental milieu. Subsequently, these differences could affect how spermatozoa interact with the environmental milieu (maturation, mixing with seminal plasma, and interacting with the environmental milieu, or female genital tract and female gamete). The emergence of sperm subpopulations as an outcome of evolution, related to the reproductive strategies of the species, genital tract structures, and copulatory and fertilization processes. This kind of approach in determining the importance of sperm subpopulations in fertilization capacity should have a practical impact for conducting reproductive technologies, inspiring and enabling new ways for the more efficient use of spermatozoa in the medical, animal breeding, and conservation fields. This manuscript is a contribution to the Special Issue in memory of Dr. Duane GarnerS

    Interactive Sonic Environments: Sonic artwork via gameplay experience

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    The purpose of this study is to investigate the use of video-game technology in the design and implementation of interactive sonic centric artworks, the purpose of which is to create and contribute to the discourse and understanding of its effectiveness in electro-acoustic composition highlighting the creative process. Key research questions include: How can the language of electro-acoustic music be placed in a new framework derived from videogame aesthetics and technology? What new creative processes need to be considered when using this medium? Moreover, what aspects of 'play' should be considered when designing the systems? The findings of this study assert that composers and sonic art practitioners need little or no coding knowledge to create exciting applications and the myriad of options available to the composer when using video-game technology is limited only by imagination. Through a cyclic process of planning, building, testing and playing these applications the project revealed advantages and unique sonic opportunities in comparison to other sonic art installations. A portfolio of selected original compositions, both fixed and open are presented by the author to complement this study. The commentary serves to place the work in context with other practitioners in the field and to provide compositional approaches that have been taken

    Co-authors, colleagues, and contributors: Complexities in collaboration and sharing lessons on academic writing

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    Academic writing, especially in the health field, is usually an interdisciplinary team effort. This paper highlights some of the trials, tribulations, and benefits of working with co-authors. This includes collaborations and co-authorship between academics from different disciplines, academics of different level of careers, and authors from countries of varying economies i.e., high-income countries (HICs) and from low-and middle-income countries (LMICs). This paper also provides advice in the form of several useful tips to lead authors and co-authors to support collaborative working

    Uso de las histonas circulantes y sus modificaciones post-traduccionales como biomarcadores en sepsis y shock séptico

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    La sepsis es una afecci√≥n potencialmente mortal causada por una respuesta anormal del hu√©sped a una infecci√≥n, produciendo respuestas fisiol√≥gicas alteradas que da√Īan los propios tejidos del paciente y pueden provocar disfunci√≥n org√°nica e incluso la muerte. Asimismo, algunos pacientes s√©pticos progresan a shock s√©ptico, caracterizado por alteraciones circulatorias, celulares y metab√≥licas sustanciales que aumentan el riesgo de mortalidad. A pesar de que la sepsis se caracteriza por un mal funcionamiento del sistema inmunol√≥gico, lo que a su vez conduce a una respuesta inmune alterada e inmunosupresi√≥n, la alta complejidad de la fisiopatolog√≠a de la sepsis requiere una mayor investigaci√≥n para comprender las respuestas inmunes que ocurren durante la sepsis. Asimismo, las histonas extracelulares circulantes han ganado relevancia como mediadores citot√≥xicos en la sepsis, ya que act√ļan como patrones moleculares asociados a da√Īo, que inducen estr√©s oxidativo y activan el inflamasoma NLRP3. Estos mecanismos median la activaci√≥n de la piroptosis, un mecanismo de muerte celular programada que produce inflamaci√≥n mediante la expresi√≥n de IL-18, IL-1ő≤ and IL-1őĪ. Sin embargo, a pesar de la evidencia de activaci√≥n del inflamasoma en las c√©lulas inmunes durante la sepsis, se desconoce si las histonas extracelulares son capaces de activar los inflamasomas endoteliales y sus consecuencias. En este trabajo destacamos el papel previamente desconocido de las histonas extracelulares, mediando la activaci√≥n del inflamasoma NLRP3 y la piroptosis en las c√©lulas endoteliales, contribuyendo a la disfunci√≥n endotelial y la desregulaci√≥n de la respuesta inmune mediada por el endotelio. Asimismo, tambi√©n demostramos c√≥mo la acetilaci√≥n de histonas disminuye la activaci√≥n de la piroptosis. Adem√°s, demostramos que la piroptosis se produce en pacientes con shock s√©ptico y los niveles de histonas circulantes se correlacionan con la expresi√≥n de citoquinas proinflamatorias y citoquinas piropt√≥ticas, la liberaci√≥n de factores de adhesi√≥n endotelial y la gravedad de la enfermedad. Proponemos la piroptosis mediada por histonas como un nuevo objetivo para desarrollar intervenciones cl√≠nicas. De manera similar, hemos analizado las respuestas inmunorelacionadas que ocurren durante las primeras etapas de la sepsis con el objetivo de proporcionar nuevos datos comparando las cantidades de citoquinas, inmunomoduladores y otros mediadores endoteliales en pacientes cr√≠ticamente enfermos no s√©pticos, s√©pticos y de shock s√©ptico. Nuestro enfoque ayudar√° a caracterizar r√°pidamente las respuestas inmunes alteradas en pacientes s√©pticos y de shock s√©ptico ingresados en la Unidad de Cuidados Intensivos. Finalmente analizamos el papel de la metilaci√≥n del ADN en el control del sistema inmune s√©ptico. Nuestros resultados demostraron el papel central de la metilaci√≥n del ADN modulando la respuesta molecular en los pacientes de shock s√©ptico y contribuyendo a la inmunosupresi√≥n, a trav√©s de la alteraci√≥n de los patrones de metilaci√≥n de los promotores de IL-10 y TREM-2.Sepsis is a life-threatening condition caused by an abnormal host response to an infection that produce altered physiological responses which damages own tissues of the patient and can result in organ dysfunction and in some cases death. Likewise, a subset of septic patients progresses to septic shock, characterized by substantial circulatory, cellular and metabolic abnormalities, which substantially increase the risk of mortality. Sepsis is characterized by a malfunction of the immune system and it can lead to an altered immune response and immunosuppression. Moreover, the high complexity of the pathophysiology of sepsis requires of further investigation to characterize the immune responses in sepsis and septic shock. Likewise, circulating extracellular histones have gained relevance as cytotoxic mediators in sepsis pathophysiology, since they act as damage-associated molecular patterns, which induce oxidative stress and activate NLRP3 inflammasome. Subsequently, inflammasome mediates pyroptosis activation, a programmed cell death mechanism that produces inflammation through the release of IL-18, IL-1ő≤ and IL-1őĪ. However, despite inflammasome activation may occur in immune cells during sepsis, it is unknown if this process also takes place in endothelial cells and particularly whether extracellular histones are capable of activating endothelial inflammasomes and their consequences. In this work we highlight a previously unknown role for extracellular histones, that mediates the activation of NLRP3 inflammasome and pyroptosis in endothelial cells by contributing to endothelial dysfunction and the dysregulation of the immune response mediated by endothelium. Likewise, we demonstrated how histone acetylation decreases pyroptosis activation. Furthermore, we show how pyroptosis occurs in septic shock patients and how circulating histone levels correlate with the expression of pro-inflammatory and pyroptotic cytokines, the release of endothelial adhesion factors and septic shock severity. We propose histone-mediated pyroptosis as a new target to develop clinical interventions. Similarly, we have analyzed the immune-related responses occurring during the early stages of sepsis with the aim of providing new data by comparing the amounts of cytokines, immune modulators and other endothelial mediators in critically-ill non-septic patients, septic and septic shock patients. Our approach will help to rapidly characterize the altered immune responses in septic and septic shock patients admitted in the Intensive Care Unit. Finally, we also analyzed the role of DNA methylation in the control of septic immune system. Our results demonstrated the central role of DNA methylation modulating the molecular response in septic shock patients and contributing to immunosuppression, through the alteration of DNA methylation patterns of IL-10 and TREM2 promoters

    Conservation agriculture affects grain and nutrient yields of Maize (Zea Mays L.) and can impact food and nutrition security in Sub-Saharan Africa

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    Maize is a major staple and plays an essential role in food and nutrition security in Sub-Saharan Africa (SSA). Conservation agriculture (CA), a climate-smart agriculture practise based on minimum soil disturbance, crop residue retention, and crop diversification, has been widely advocated but without extensive research on the impact it may have on maize nutrient composition, and food and nutrition security. This study assessed the grain yield, macro- and micronutrient mineral content, and nutrient yield of eight maize varieties grown in Malawi, and how these are affected by CA practises over two seasons. The minerals were analysed by inductively coupled plasma (ICP) coupled to optical emission spectroscopy (OES) and to mass spectroscopy (MS). Grain yield and Se content differed among the varieties, while C, N, Fe, K, Mg, Mn, P, and Zn were similar. The local variety Kanjerenjere showed lowest grain and nutrient yields. The open-pollinated varieties (OPVs) concentrated more minerals than the F1 hybrids, but the latter showed higher yields for both grain and nutrients. Typical consumption of the eight maize varieties could fully meet the protein and Mg dietary reference intake (DRIs) of Malawian children (1‚Äď3 years), as well as Mg and Mn needs of adult women (19‚Äď50 years), but their contribution to dietary requirements was low for Fe (39‚Äď41%) and K (13‚Äď21%). The trials showed that CA increased grain yield (1.2- to 1.8-fold) and Se content (1.1- to 1.7-fold), but that it had no effect on C, K, Mg, P, and Zn, and that N (1.1- to 1.2-fold), Mn (1.1- to 1.8-fold), and Fe (1.3- to 3.4-fold) were reduced. The high increase in grain yield under CA treatments resulted in increased yields of protein and Se, no effect on the yields of K, Mg, Mn, P, Zn, and reduced Fe yield. Conservation agriculture could contribute in reducing the risk of Se deficiency in Malawian women and children but exacerbates the risk of Fe deficiency. A combination of strategies will be needed to mitigate some of the foreseen effects of climate change on agriculture, and food and nutrition security, and improve nutrient intake

    The applied psychology of addictive orientations : studies in a 12-step treatment context.

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    The clinical data for the studies was collected at The PROMIS Recovery Centre, a Minnesota Model treatmentc entre for addictions,w hich encouragesth e membership and use of the 12 step Anonymous Fellowships, and is abstinence based. The area of addiction is contextualised in a review chapter which focuses on research relating to the phenomenon of cross addiction. A study examining the concept of "addictive orientations" in male and female addicts is described, which develops a study conductedb y StephensonM, aggi, Lefever, & Morojele (1995). This presents study found a four factor solution which appeared to be subdivisions of the previously found Hedonism and Nurturance factors. Self orientated nurturance (both food dimensions, shopping and caffeine), Other orientated nurturance (both compulsive helping dimensions and work), Sensation seeking hedonism (Drugs, prescription drugs, nicotine and marginally alcohol), and Power related hedonism (Both relationship dimensions, sex and gambling. This concept of "addictive orientations" is further explored in a non-clinical population, where again a four factor solution was found, very similar to that in the clinical population. This was thought to indicate that in terms of addictive orientation a pattern already exists in this non-clinical population and that consideration should be given to why this is the case. These orientations are examined in terms of gender differences. It is suggested that the differences between genders reflect power-related role relationships between the sexes. In order to further elaborate the significance and meaning behind these orientations, the next two chapters look at the contribution of personality variables and how addictive orientations relate to psychiatric symptomatology. Personality variables were differentially, and to a considerable extent predictably involved with the four factors for both males and females.Conscientiousness as positively associated with "Other orientated Nurturance" and negatively associated with "Sensation seeking hedonism" (particularly for men). Neuroticism had a particularly strong association with the "Self orientated Nurturance" factor in the female population. More than twice the symptomatology variance was explained by the factor scores for females than it was for males. The most important factorial predictors for psychiatric symptomatology were the "Power related hedonism" factor for males, and "Self oriented nurturance" for females. The results are discussed from theoretical and treatment perspectives

    Differences in external match load metrics between professional and semi-professional football players

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    This study aimed to investigate the differences in external match load between professional and semi-professional footballers, and also aimed to investigate whether periods of fixture congestion throughout the season had an effect on the external match load of players at either the professional or semi-professional level. This study consisted of data from 51 football players, 21 professional and 30 semi-professional footballers, playing in the 2019/2020 football season. The data collected was obtained via MEMS (microelectromechanical systems) devices, which measured the players‚Äô total distance, high-speed distance, accelerations, decelerations and player load. Once the external match load data was quantified, a comparison between playing levels took place using a univariate ANOVA. A two-way repeated measures ANOVA was used to examine if significant differences existed in external match load variables across player performance level (2 levels) and time of the season (3 levels) during periods of time when teams experienced fixture congestion. This study found that professional players travelled significantly greater distances in a 90 minute match (10.93 ¬Ī 2.46 vs 9.02 ¬Ī 1.56 km respectively; P<0.001). No differences in high-speed distance were observed between playing level (P=0.70), whereas semiprofessional players recorded significantly greater player load value than the professional players (88.6 ¬Ī 12.2 vs 68.8 ¬Ī 18.9% respectively; P<0.001). Periods of fixture congestion were not found to significantly affect any of the match load variables at either playing level despite the time of the season. In conclusion, neither playing level was found to exhibit a superior level of external match load. The other major finding of this thesis was that fixture congestion did not affect match load. Further research is required to quantify and compare the external match load at the non-elite professional and semi-professional level of football, as these levels of football are largely ignored in this field of literature

    The company she keeps : The social and interpersonal construction of girls same sex friendships

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    This thesis begins a critical analysis of girls' 'private' interpersonal and social relations as they are enacted within two school settings. It is the study of these marginal subordinated worlds productivity of forms of femininity which provides the main narrative of this project. I seek to understand these processes of (best) friendship construction through a feminist multi-disciplinary frame, drawing upon cultural studies, psychoanalysis and accounts of gender politics. I argue that the investments girls bring to their homosocial alliances and boundary drawing narry a psychological compulsion which is complexly connected to their own experiences within the mother/daughter bond as well as reflecting positively an immense social debt to the permissions girls have to be nurturant and ; negatively their own reproduction of oppressive exclusionary practices. Best friendship in particular gives girls therefore, the experience of 'monogamy' continuous of maternal/daughter identification, reminiscent of their positioning inside monopolistic forms of heterosexuality. But these subcultures also represent a subversive discontinuity to the public dominance of boys/teachers/adults in schools and to the ideologies and practices of heterosociality and heterosexuality. By taking seriously their transmission of the values of friendship in their chosen form of notes and diaries for example, I was able to access the means whereby they were able to resist their surveillance and control by those in power over them. I conclude by arguing that it is through a recognition of the valency of these indivisiblly positive and negative aspects to girls cultures that Equal Opportunities practitioners must begin if they are serious about their ambitions. Methods have to be made which enable girls to transfer their 'private' solidarities into the 'public' realm, which unquestionably demands contesting with them the causes and consequences of their implication in the divisions which also contaminate their lives and weaken them
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