972 resultados para Multifaceted explanation
Resumo:
The visual angle that is projected by an object (e.g. a ball) on the retina depends on the object's size and distance. Without further information, however, the visual angle is ambiguous with respect to size and distance, because equal visual angles can be obtained from a big ball at a longer distance and a smaller one at a correspondingly shorter distance. Failure to recover the true 3D structure of the object (e.g. a ball's physical size) causing the ambiguous retinal image can lead to a timing error when catching the ball. Two opposing views are currently prevailing on how people resolve this ambiguity when estimating time to contact. One explanation challenges any inference about what causes the retinal image (i.e. the necessity to recover this 3D structure), and instead favors a direct analysis of optic flow. In contrast, the second view suggests that action timing could be rather based on obtaining an estimate of the 3D structure of the scene. With the latter, systematic errors will be predicted if our inference of the 3D structure fails to reveal the underlying cause of the retinal image. Here we show that hand closure in catching virtual balls is triggered by visual angle, using an assumption of a constant ball size. As a consequence of this assumption, hand closure starts when the ball is at similar distance across trials. From that distance on, the remaining arrival time, therefore, depends on ball's speed. In order to time the catch successfully, closing time was coupled with ball's speed during the motor phase. This strategy led to an increased precision in catching but at the cost of committing systematic errors.
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Past research in using ICTs (Information and Communication Technologies) in interpersonal communication showed that age plays an important role. There is a general assumption that the elderly are left behind regarding the adoption and the use of ICTs. Furthermore, elders tend to use ICTs mainly for instrumental purposes and the use is rather non-sophisticated. When elders are using ICTs to maintain their social network, similar patterns could be found: They start using internet, or intensify its use, when their children move abroad while they might decrease using the tool if the motivation ends. In this research we explore elders' incentives to go online and use internet services to communicate; the type of agencies they use to communicate with children and grandchildren abroad; and the situations that make them stop using the ICTs or even reject internet mediated communications. We base our discussion on the empirical evidence the two authors gathered in different cities and countries: Barcelona, Romania, Toronto, Los Angeles, Montevideo and Lima, through semi-structured interviews and observation, with people aged 60 years old and over. The results show that the ability for using ICT tools in an autonomous way is a better explanation than age. In this, we distinguish between assisted users and autonomous users. We found that oldest seniors and those seniors who are less socially active are more likely to be assisted users than those who are socially or professionally active. For them communication with their children and grandchildren abroad follows no agency or it is mediated by significant others from their local social network, who are able to use ICTs and select specific information to share, in the second step, with the elder. For some younger participants the use of ICTs is rather situational and imposed by their children or grandchildren, who installed the tool in the first place and assisted them in using it. Finally, other elders describe a proficient and independent use of ICTs so they use the devices and services the way they want to.We discuss the implications of the patterns in using ICTs, for elders' social life and their relationships with children and grandchildren. First, we emphasis the fact that those elders rejecting the ICTs or being unskilled in using them to communicate might be left out from their family circle, particularly when children are abroad -they would experience more isolation. Second, we underline the fact that when children and grandchildren are the ones that control the ICTs used by their parents and grandparents, they are controlling also the information flow and this will redefine the power relations between elders and their younger relatives.
Resumo:
OBJECTIVE: The aim of this study is to review highly cited articles that focus on non-publication of studies, and to develop a consistent and comprehensive approach to defining (non-) dissemination of research findings. SETTING: We performed a scoping review of definitions of the term 'publication bias' in highly cited publications. PARTICIPANTS: Ideas and experiences of a core group of authors were collected in a draft document, which was complemented by the findings from our literature search. INTERVENTIONS: The draft document including findings from the literature search was circulated to an international group of experts and revised until no additional ideas emerged and consensus was reached. PRIMARY OUTCOMES: We propose a new approach to the comprehensive conceptualisation of (non-) dissemination of research. SECONDARY OUTCOMES: Our 'What, Who and Why?' approach includes issues that need to be considered when disseminating research findings (What?), the different players who should assume responsibility during the various stages of conducting a clinical trial and disseminating clinical trial documents (Who?), and motivations that might lead the various players to disseminate findings selectively, thereby introducing bias in the dissemination process (Why?). CONCLUSIONS: Our comprehensive framework of (non-) dissemination of research findings, based on the results of a scoping literature search and expert consensus will facilitate the development of future policies and guidelines regarding the multifaceted issue of selective publication, historically referred to as 'publication bias'.
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In this paper we shall try to explain why speakers experience their languages so passionately. One explanation is based on the role language plays in the construction of the community and in the fact that it is a clear mark of belonging. Furthermore, we support another reason. Speakers experience their language as something received from their ancestors and that they are obliged to transmit to their descendents, an imperative which carries an extraordinary emotional charge. In fact, fear of the death of a language is experienced as an act of irreparable non-fulfilment. Why? We believe that language is one of the most evident signs of community, much more than the sum of the individuals of which it is composed. Indeed, it is a long-lasting entity projected into both the past and the future and which, moreover, accumulates within the language the whole of the culture. In the survival of the community and the language we find a response, even though it may be illusory, to the need for transcendence: our ancestors live on in our language and we, if we meet our obligations, live on in the language of our descendents
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This paper explores the role of inequity aversion as an explanation for observed behavior in experimental Cournot oligopolies. We show that inequity aversion can change the nature of the strategic interaction: quantities are strategic substitutes for sufficiently asymmetric output levels but strategic complements otherwise. We find that inequity aversion can explain why: (i) some experiments result in higher than Cournot-Nash production levels while others result in lower, (ii) collusion often occurs with only two players whereas with three or more players market outcomes are very close to Cournot-Nash, and (iii) players often achieve equal profits in asymmetric Cournot oligopoly.
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The vulnerability to infection of newborns is associated with a limited ability to mount efficient immune responses. High concentrations of adenosine and prostaglandins in the fetal and neonatal circulation hamper the antimicrobial responses of newborn immune cells. However, the existence of mechanisms counterbalancing neonatal immunosuppression has not been investigated. Remarkably, circulating levels of macrophage migration inhibitory factor (MIF), a proinflammatory immunoregulatory cytokine expressed constitutively, were 10-fold higher in newborns than in children and adults. Newborn monocytes expressed high levels of MIF and released MIF upon stimulation with Escherichia coli and group B Streptococcus, the leading pathogens of early-onset neonatal sepsis. Inhibition of MIF activity or MIF expression reduced microbial product-induced phosphorylation of p38 and ERK1/2 mitogen-activated protein kinases and secretion of cytokines. Recombinant MIF used at newborn, but not adult, concentrations counterregulated adenosine and prostaglandin E2-mediated inhibition of ERK1/2 activation and TNF production in newborn monocytes exposed to E. coli. In agreement with the concept that once infection is established high levels of MIF are detrimental to the host, treatment with a small molecule inhibitor of MIF reduced systemic inflammatory response, bacterial proliferation, and mortality of septic newborn mice. Altogether, these data provide a mechanistic explanation for how newborns may cope with an immunosuppressive environment to maintain a certain threshold of innate defenses. However, the same defense mechanisms may be at the expense of the host in conditions of severe infection, suggesting that MIF could represent a potential attractive target for immune-modulating adjunctive therapies for neonatal sepsis.
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Objective:To present a detailed explanation on the processing of magnetic susceptibility weighted imaging (SWI), demonstrating the effects of echo time and sensitive mask on the differentiation between calcification and hemosiderin.Materials and Methods:Computed tomography and magnetic resonance (magnitude and phase) images of six patients (age range 41– 54 years; four men) were retrospectively selected. The SWI images processing was performed using the Matlab’s own routine.Results:Four out of the six patients showed calcifications at computed tomography images and their SWI images demonstrated hyperintense signal at the calcification regions. The other patients did not show any calcifications at computed tomography, and SWI revealed the presence of hemosiderin deposits with hypointense signal.Conclusion:The selection of echo time and of the mask may change all the information on SWI images, and compromise the diagnostic reliability. Amongst the possible masks, the authors highlight that the sigmoid mask allows for contrasting calcifications and hemosiderin on a single SWI image.
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We study the dynamics of shear-band formation and evolution using a simple rheological model. The description couples the local structure and viscosity to the applied shear stress. We consider in detail the Couette geometry, where the model is solved iteratively with the Navier-Stokes equation to obtain the time evolution of the local velocity and viscosity fields. It is found that the underlying reason for dynamic effects is the nonhomogeneous shear distribution, which is amplified due to a positive feedback between the flow field and the viscosity response of the shear thinning fluid. This offers a simple explanation for the recent observations of transient shear banding in time-dependent fluids. Extensions to more complicated rheological systems are considered.
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The possibility of printing two-dimensional micropatterns of biomolecule solutions is of great interest in many fields of research in biomedicine, from cell-growth and development studies to the investigation of the mechanisms of communication between cells. Although laser-induced forward transfer (LIFT) has been extensively used to print micrometric droplets of biological solutions, the fabrication of complex patterns depends on the feasibility of the technique to print micron-sized lines of aqueous solutions. In this study we investigate such a possibility through the analysis of the influence of droplet spacing of a water and glycerol solution on the morphology of the features printed by LIFT. We prove that it is indeed possible to print long and uniform continuous lines by controlling the overlap between adjacent droplets. We show how, depending on droplet spacing, several printed morphologies are generated, and we offer, in addition, a simple explanation of the observed behavior based on the jetting dynamics characteristic of the LIFT of liquids.
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Several authors in the 17th century used the atomic hypothesis to explain observable phenomena. This paper analyzes some ideas about chemical transformation proposed by the English physician Walter Charleton. In Physiologia Epicuro-Gassendo-Charltoniana (London, 1654), Charleton examined philosophical aspects of the atomic theory, and suggested that the best explanation for all natural phenomena would be only in terms of atoms and their motions. Sometimes, however, he had to attribute to the atoms some kind of "internal virtue", to explain more complex properties of the matter. His idea of "element", and the little use of experimentation and quantification, also limited the range of Charleton's theory.
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Here we discuss two consecutive MERLIN observations of the X-ray binary LS I +61° 303 . The first observation shows a double-sided jet extending up to about 200 AU on both sides of a central source. The jet shows a bent S-shaped structure similar to the one displayed by the well-known precessing jet of SS 433 . The precession suggested in the first MERLIN image becomes evident in the second one, showing a one-sided bent jet significantly rotated with respect to the jet of the day before. We conclude that the derived precession of the relativistic (beta=0.6) jet explains puzzling previous VLBI results. Moreover, the fact that the precession is fast could be the explanation of the never understood short term (days) variability of the associated gamma-ray source 2CG 135+01 / 3EG J0241+6103
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The article describes and summarizes some results of the research Identification of the difficulties, collection of good practices and analysis of the improvement processes in Secondary Education Institutes of Catalonia (2011). An approach to the situation of conviviality in the Catalan public Secondary schools gathering the perception of the management teams, through an ethnographic approach and of analysis of the stories. It has its origin in a work commissioned from the General Subdirectorate of Permanent Teacher Training of the Generalitat of Catalonia, developed in the context of the module “Conviviality and Organization of Centres”, within the program of permanent training of management teams. It falls in line with action-oriented research to improve practice. The paper gathers and synthesizes the results obtained in the collection and systematization of the proposed improvements. It is structured in three parts: a) a theoretical analysis which conceptualizes violence / conviviality and sense of good practices; b) the explanation of the design, methodology and development of research and c) the categorization of the improvement proposals and the conclusions of the work
Resumo:
Dreaming is a pure form of phenomenality, created by the brain untouched by external stimulation or behavioral activity, yet including a full range of phenomenal contents. Thus, it has been suggested that the dreaming brain could be used as a model system in a biological research program on consciousness (Revonsuo, 2006). In the present thesis, the philosophical view of biological realism is accepted, and thus, dreaming is considered as a natural biological phenomenon, explainable in naturalistic terms. The major theoretical contribution of the present thesis is that it explores dreaming from a multidisciplinary perspective, integrating information from various fields of science, such as dream research, consciousness research, evolutionary psychology, and cognitive neuroscience. Further, it places dreaming into a multilevel framework, and investigates the constitutive, etiological, and contextual explanations for dreaming. Currently, the only theory offering a full multilevel explanation for dreaming, that is, a theory including constitutive, etiological, and contextual level explanations, is the Threat Simulation Theory (TST) (Revonsuo, 2000a; 2000b). The empirical significance of the present thesis lies in the tests conducted to test this specific theory put forth to explain the form, content, and biological function of dreaming. The first step in the empirical testing of the TST was to define exact criteria for what is a ‘threatening event’ in dreams, and then to develop a detailed and reliable content analysis scale with which it is possible to empirically explore and quantify threatening events in dreams. The second step was to seek answers to the following questions derived from the TST: How frequent threatening events are in dreams? What kind of qualities these events have? How threatening events in dreams relate to the most recently encoded or the most salient memory traces of threatening events experienced in waking life? What are the effects of exposure to severe waking life threat on dreams? The results reveal that threatening events are relatively frequent in dreams, and that the simulated threats are realistic. The most common threats include aggression, are targeted mainly against the dream self, and include simulations of relevant and appropriate defensive actions. Further, real threat experiences activate the threat simulation system in a unique manner, and dream content is modulated by the activation of long term episodic memory traces with highest negative saliency. To sum up, most of the predictions of the TST tested in this thesis received considerable support. The TST presents a strong argument that explains the specific design of dreams as threat simulations. The TST also offers a plausible explanation for why dreaming would have been selected for: because dreaming interacted with the environment in such a way that enhanced fitness of ancestral humans. By referring to a single threat simulation mechanism it furthermore manages to explain a wide variety of dream content data that already exists in the literature, and to predict the overall statistical patterns of threat content in different samples of dreams. The TST and the empirical tests conducted to test the theory are a prime example of what a multidisciplinary approach to mental phenomena can accomplish. Thus far, dreaming seems to have always resided in the periphery of science, never regarded worth to be studied by the mainstream. Nevertheless, when brought to the spotlight, the study of dreaming can greatly benefit from ideas in diverse branches of science. Vice versa, knowledge learned from the study of dreaming can be applied in various disciplines. The main contribution of the present thesis lies in putting dreaming back where it belongs, that is, into the spotlight in the cross-road of various disciplines.
Resumo:
In this paper, an overview about philosophy of science, the concept of "theory" and some characteristics of a"good"theory (1- ordination and explanation of the facts, 2- proposal of problems, and 3- simplicity and funcionality) are initialy introduced. Following, some historical landmarks of acidity and basicity and a summary of the main acid-base theories of the XX century (Arrhenius, solvent systems, protonic, electronic, Lux, Usanovich and ionotropic) are presented. Historical and conceptual relations between these theories are discussed and the three characteristics of a "good" theory are applied. The results showed that the protonic and eletronic theories are the "best". Some discussion of the implications to chemical education are presented too.
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Un sistema ERP és una aplicació que ens permet fer la gestió dels processos de negoci de una forma àgil. Aquest projecte tracta sobre l’estudi per a la implantació d’un ERP en una empresa de fabricació de material per a minusvàlids. Inicialment es farà una part teòrica sobre el que són els sistemes ERP. A continuació, s’analitza el funcionament de l’empresa on es realitzarà l’estudi. Finalment, s’estudien tres solucions ERP del mercat actual i es selecciona la que millor s’adapta a les necessitats i requeriments en vistes a una possible implantació.