2,761 research outputs found
Power, ERP systems and resistance to management accounting: a case study
This paper reports an intensive longitudinal case study carried out in a Portuguese manufacturing organisation in which attempts to promote change through management accounting were made in recent years. In a first pilot visit to the organisation, two puzzling observations were made. Firstly, and particularly in the manufacturing area of the organisation, management accounting systems introduced in recent years were not being used in everyday interactions and practices. Secondly, a newly introduced ERP system was having no apparent impact on management accounting or on the work of management accountants. We found that these observations were related to issues of power. There were different and conflicting conceptions of which rules should be followed in the manufacturing area, and strategic attempts to enact those conceptions (or to resist alternative ones). This paper draws on the insights of the Circuits of Power (Clegg, 1989a) in order to explain, in theoretically informed manner, the puzzling observations in the case.
THE INFLUENCE OF SEX AND ANTHROPOMETRIC PARAMETERS ON THE PARTIAL AND TOTAL VELOCITlES OF PORTUGUESE TOP SWIMMERS
This work studies the variation of some performance indicators - the relative contributions of partial velocities on total speed, the increase of speed induced by the action of lower limbs and the coordination degree of the action of both upper and lower limbs, in order to achieve maximum speed - on Portuguese top swimmers, in the four competitive strokes. The performance indicators were analyzed as functions of the sex of the swimmers and of selected anthropometric parameters (lengths, frontal areas and cross sectional areas of body segments). Twenty eight swimmers, fourteen of each sex, representing one of the best Portuguese competitive teams, were submitted to a standard test situation and to a photographic procedure. Their best times, velocities and somatic characteristics were thereafter determined. 'T' tests and analysis of variance were computed to account for differences in the performance indicators, between male and female swimmers. Anthropometric and performance variables were correlated inside each group. The values of 'T' and 'F' showed significant differences between average scores of male and female groups (
Symbols are not uniquely human
Modern semiotics is a branch of logics that formally defines symbol-based communication. In recent years, the semiotic classification of signs has been invoked to support the notion that symbols are uniquely human. Here we show that alarm-calls such as those used by African vervet monkeys (Cercopithecus aethiops), logically satisfy the semiotic definition of symbol. We also show that the acquisition of vocal symbols in vervet monkeys can be successfully simulated by a computer program based on minimal semiotic and neurobiological constraints. The simulations indicate that learning depends on the tutor-predator ratio, and that apprentice-generated auditory mistakes in vocal symbol interpretation have little effect on the learning rates of apprentices (up to 80% of mistakes are tolerated). In contrast, just 10% of apprentice-generated visual mistakes in predator identification will prevent any vocal symbol to be correctly associated with a predator call in a stable manner. Tutor unreliability was also deleterious to vocal symbol learning: a mere 5% of âlyingâ tutors were able to completely disrupt symbol learning, invariably leading to the acquisition of incorrect associations by apprentices. Our investigation corroborates the existence of vocal symbols in a non-human species, and indicates that symbolic competence emerges spontaneously from classical associative learning mechanisms when the conditioned stimuli are self-generated, arbitrary and socially efficacious. We propose that more exclusive properties of human language, such as syntax, may derive from the evolution of higher-order domains for neural association, more removed from both the sensory input and the motor output, able to support the gradual complexification of grammatical categories into syntax
Production and characterization of activated carbons made from sunflower stems
Activated carbons (ACs) are artificial materials, prepared from natural or synthetic precursors that
are worldwide extensively used. The ACs main characteristics are the noticeable adsorption
capabilities provided by the highly developed porous structure and the rich surface chemistry.
Because of their versatility and properties the final material can be tailored to have specific
properties suitable for a wide range of applications such as medical uses, gas storage, removal of
pollutants and odours, gas separation and purification as well as in catalysis. With the increase of
activated carbon demand, one of the main challenges lies in the attempt to find new precursors,
which are cheap and accessible with good valorisation potential, like industrial and agricultural
residues.
In the present work we report the production of ACs from sunflower stems, an agricultural
by-product, through a physical activation process by CO2 and H2O, using a single step
carbonisation at 400ÂșC, which as far as it came to our knowledge was never made for this precursor
Semiotics and Human-Robot Interaction
Keywords: Semi-autonomous robot, human-robot interaction, semiotics. Abstract: This paper describes a robot control architecture supported on a human-robot interaction model obtained directly from semiotics concepts. The architecture is composed of a set of objects defined after a semiotic sign model. Simulation experiments using unicycle robots are presented that illustrate the interactions within a team of robots equipped with skills similar to those used in human-robot interactions.
Kinetics and Reaction Mechanisms for Methylidyne Radical Reactions with Small Hydrocarbons
The chemical evolution with respect to time of complex macroscopic mixtures such as interstellar clouds and Titanâs atmosphere is governed via a mutual competition between thousands of simultaneous processes, including thousands of chemical reactions. Chemical kinetic modeling, which attempts to understand their macroscopic observables as well as their overall reaction mechanism through a detailed understanding of their microscopic reactions and processes, thus require thousands of rate coefficients and product distributions. At present, however, just a small fraction of these have been well-studied and measured; in addition, at the relevant low temperatures, such information becomes even more scarce. Due to the recent developments in both theoretical kinetics as well as in ab initio electronic structure calculations, it is now possible to predict accurate reaction rate coefficients and product distributions from first-principles at various temperatures, often in less time, than through the running of an experiment. Here, the results of a first principles theoretical investigation into both the reaction rate coefficients as well as the final product distributions for the reactions between the ground state CH radical (X2Î ) and various C1-C3 hydrocarbons is presented; together, these constitute a set of reactions important to modeling efforts relevant to mixtures such as interstellar clouds and Titanâs atmosphere
A Estação PaleolĂtica do Cerro (Vila Nova de Gaia, Noroeste de Portugal): caracterização preliminar dos utensĂlios com configuração bifacial
A estação paleolĂtica do Cerro foi descoberta em 1988. Entre 1989 e 1992 realizaram-se trĂȘs campanhas de escavação que permitiram recolher um importante conjunto de artefactos lĂticos talhados a partir de seixos rolados de quartzito, atribuĂveis ao PaleolĂtico Inferior. Do ponto de vista geoarqueolĂłgico, estes artefactos associam-se a coluviĂ”es, que se sobrepĂ”em a uma formação marinha implantada a cerca de 22 m n.m.a.m. O estudo das peças com configuração bifacial (em que tambĂ©m se incluem as parcialmente bifaciais e as unifaciais) revelou a existĂȘncia de duas cadeias operatĂłrias, globalmente expeditas, que visaram, sobretudo, a criação de utensĂlios com extremidade distal apontada. Estas cadeias operatĂłrias mais do que se ligarem a opçÔes de natureza morfolĂłgica parecem antes constituir uma resposta aos constrangimentos impostos pela volumetria dos suportes utilizados, visando a sua eventual adequação a distintas funcionalidades.The Palaeolithic site of Cerro was discovered in 1988. Between 1989 and 1992 three excavation seasons were carried out, which allowed collecting an important set of macrolithic stone tools most of them made of quartzite pebbles, possibly dating from the Lower Palaeolithic. From a geoarchaeological point of view, these stone tools were associated with colluvial deposits which overlay a marine formation c. 22 m a.s.l. The study of the bifacial shaped tools (including the parcial bifacial shaped and the unifacial tools) allowed the identification of two chaĂźnes operatoires, basically expedite, oriented towards the production of pointed tools. These chaĂźnes operatoires do not seem to be linked to morphological options but instead they may be a response to the constraints imposed by the volumetry of the blanks, possibly adapting them to distinct funcionalities
Post-impact fire resistance of T-stub joint component, Numerical evaluation
Current paper presents a finite element analyses for the characterization of the nonlinear behaviour of bolted t-stub component subject to impact loading followed by fire. The proposed numerical model has previously validated against experimental results under monotonic static loading at ambient and elevated temperatures (Ribeiro etal., 2013). 3D solid and contact elements from the finite element package Abaqus are used to perform the structural model. The temperature dependent material properties, the geometrical and material nonlinearities (including the strain rate sensitivity) were taken into account to predict the failure of the t-stub. A parametric study was conducted to to provide insight into the overall behavior, namely their stiffness, resistance, ductility and failure modes due to the effects of dynamic loading followed by fire
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