We studied patients with left visual extinction following right hemisphere damage in a simple manual reaction time task using brief visual stimuli. With unilateral lateralized stimuli the patients showed a high proportion of unwanted, reflex-like saccades to either side of stimulation. In contrast, with bilateral stimuli there was an overall decrease in the proportion of unwanted saccades, and the vast majority of them were directed toward the ipsilesional side. The implications of these results for the Findlay & Walker model are (...) discussed. (shrink)
Scholars have noted the need to examine the psychometric properties of measures that can be used in evaluating moral education programs. The present study was designed to examine the best?fitting factor model of a commonly?used measure of prosocial moral reasoning (PROM) across samples from Brazil and the USA, gender and adolescent age groups. The samples consisted of 619 college students (M age = 20.59 years, SD = 4.08; 41% men, 59% women) and 239 middle and high school students (M age (...) = 14.02 years, SD = 3.04; 45% boys, 55% girls) from the USA. There were 114 college students (M age = 21.81, SD = 4.33; 35% men, 65% women) and 136 middle and high school students (M age = 14.93 years, SD = 1.55; 42% boys, 58% girls) from Brazil. A series of (multigroup) confirmatory factor analyses were conducted to test the best fitting factor structure of the PROM and the invariance of this factor structure across culture, gender and age groups. Evidence for measurement invariance was found such that a four?factor model was a slightly better fitting model than the five?factor model across all groups. Discussion focuses on theoretical and methodological implications of the findings. (shrink)
This study examined relations between parenting dimensions (involvement, autonomy support and structure) and adolescents' moral values internalisation. A sample of 101 adolescents (71% female; 76% white; M age = 16.10, SD = 1.17) reported on the parenting behaviour of one of their parents and on their own moral values. Four forms of values regulation were assessed (external, introjected, identified and integrated), as well as overall internalisation. Structure was positively linked to external and introjected regulation, involvement was positively associated with identified (...) and integrated regulation and structure was negatively linked to overall internalisation. Additionally, positive interactions were found for autonomy support and involvement predicting identified and integrated regulation. Implications for parenting and moral education are discussed. (shrink)
This study examined the hypothesis that religiosity would be differentially related to six types of adolescent prosocial behaviour, and that these relations would be mediated by the prosocial value of kindness. Self?report data were collected from 142 high school students (63 per cent female; 91 per cent White; M age?=?16.8, S?=?.80). Religiosity was a significant positive predictor of kindness, as well as compliant, anonymous and altruistic prosocial behaviour, but not public, dire and emotional prosocial behaviour. Associations between religiosity and both (...) compliant and altruistic prosocial behaviours were mediated by kindness. Direct and indirect paths were found between religiosity and anonymous prosocial behaviour. Thus, partial support was found for the mediational hypothesis. Discussion focused on the utility of distinguishing among different types of prosocial behaviours and on the role of religion and values in promoting moral education. (shrink)
There are three concerns regarding Rachlin's altruism model. First, proximal causal mechanisms such as those identified by cognitive neuroscientists and behavioral neuropharmacologists are not emphasized. Second, there is a lack of clear testable hypotheses. And third, extreme forms of altruism are emphasized rather than common forms. We focus on an overarching theme – proximal mechanisms of individual differences in altruism.
In the 1960s molecular population geneticists used Monte Carlo experiments to evaluate particular diffusion equation models. In this paper I examine the nature of this comparative evaluation and argue for three claims: first, Monte Carlo experiments are genuine experiments: second, Monte Carlo experiments can provide an important meansfor evaluating the adequacy of highly idealized theoretical models; and, third, the evaluation of the computational adequacy of a diffusion model with Monte Carlo experiments is significantlydifferent from the evaluation (...) of the emperical adequacy of the same diffusion model. (shrink)
Exploring how people represent natural categories is a key step toward developing a better understanding of how people learn, form memories, and make decisions. Much research on categorization has focused on artificial categories that are created in the laboratory, since studying natural categories defined on high-dimensional stimuli such as images is methodologically challenging. Recent work has produced methods for identifying these representations from observed behavior, such as reverse correlation (RC). We compare RC against an alternative method for inferring the structure (...) of natural categories called Markov chain Monte Carlo with People (MCMCP). Based on an algorithm used in computer science and statistics, MCMCP provides a way to sample from the set of stimuli associated with a natural category. We apply MCMCP and RC to the problem of recovering natural categories that correspond to two kinds of facial affect (happy and sad) from realistic images of faces. Our results show that MCMCP requires fewer trials to obtain a higher quality estimate of people’s mental representations of these two categories. (shrink)
I never met Gian-Carlo Rota but I have often made references to his writings on the philosophy of mathematics, sometimes agreeing, sometimes disagreeing. In this paper I will discuss his views concerning four questions: the existence of mathematical objects, definition in mathematics, the notion of proof, the relation of philosophy of mathematics to mathematics.
A decomposition model of Net Final Values (NFV), named Systemic Value Added (SVA), is proposed for decision-making purposes, based on a systemic approach introduced in Magni [Magni, C. A. (2003), Bulletin of Economic Research 55(2), 149–176; Magni, C. A. (2004) Economic Modelling 21, 595–617]. The model translates the notion of excess profit giving formal expression to a counterfactual alternative available to the decision maker. Relations with other decomposition models are studied, among which Stewart’s [Stewart, G.B. (1991), The Quest for Value: (...) The EVA™ Management Guide, Harper Collins, Publishers Inc]. The index here introduced differs from Stewart’s Economic Value Added (EVA) in that it rests on a different interpretation of the notion of excess profit and is formally connected with the EVA model by means of a shadow project. The SVA is formally and conceptually threefold, in that it is economic, financial, accounting-flavoured. Some results are offered, providing sufficient and necessary conditions for decomposing NFV. Relations between a project’s SVA and its shadow project’s EVA are shown, all results of Pressacco and Stucchi [Pressacco, F. and Stucchi, P. (1997), Rivista di Matematica per le Scienze Economiche e Sociali 20, 165–185] are proved by making use of the systemic approach and the shadow counterparts of those results are also shown. (shrink)
What is quantum mechanics about? The most natural way to interpret quantum mechanics realistically as a theory about the world might seem to be what is called wave function ontology: the view according to which the wave function mathematically represents in a complete way fundamentally all there is in the world. Erwin Schroedinger was one of the first proponents of such a view, but he dismissed it after he realized it led to macroscopic superpositions (if the wave function evolves in (...) time according to the equations that has his name). The Many-Worlds interpretation1 accepts the existence of such macroscopic superpositions but takes it that they can never be observed. Superposed objects and superposed observers split together in different worlds of the type of the one we appear to live in. For these who, like Schroedinger, think that macroscopic superpositions are a problem, the common wisdom is that there are two alternative views: "Either the wave function, as given by the Schroedinger equation, is not everything, or is not right" [Bell 1987]. The deBroglie-Bohm theory, now commonly known as Bohmian Mechanics, takes the first option: the description provided by a Schroedinger-evolving wave function is supplemented by the information provided by the configuration of the particles. The second possibility consists in assuming that, while the wave function provides the complete description of the system, its temporal evolution is not given by the Schroedinger equation. Rather, the usual Schroedinger evolution is interrupted by random and sudden "collapses". The most promising theory of this kind is the GRW theory, named after the scientists that developed it: Gian Carlo Ghirardi, Alberto Rimini and Tullio Weber.. It seems tempting to think that in GRW we can take the wave function ontologically seriously and avoid the problem of macroscopic superpositions just allowing for quantum jumps. In this paper we will argue that such "bare" wave function ontology is not possible, neither for GRW nor for any other quantum theory: quantum mechanics cannot be about the wave function simpliciter. That is, we need more structure than the one provided by the wave function. As a response, quantum theories about the wave function can be supplemented with structure, without taking it as an additional ontology. We argue in reply that such "dressed-up" versions of wave function ontology are not sensible, since they compromise the acceptability of the theory as a satisfactory fundamental physical theory. Therefore we maintain that: 1- Strictly speaking, it is not possible to interpret quantum theories as theories about the wave function; 2- Even if the wave function is supplemented by additional non-ontological structures, there are reasons not to take the resulting theory seriously. Moreover, we will argue that any of the traditional responses to the measurement problem of quantum mechanics (Bohmian mechanics, GRW and Many-Worlds), contrarily to what commonly believed, share a common structure. That is, we maintain that: 3- All quantum theories should be regarded as theories in which physical objects are constituted by a primitive ontology. The primitive ontology is mathematically represented in the theory by a mathematical entity in three-dimensional space, or space-time. (shrink)
The article is the consequence of some critical notes to the contribution of Paolo Bellan, arising from reading of essays of Francesco Emmolo and Carlo Sini and the assumption of a purely phenomenological perspective in the interpretation of the processes of acquisition of scientific knowledge.
This paper reviews and enhances numerical models for determining thermal, elastic and electrical properties of carbon nanotube-reinforced polymer composites. For the determination of the effective stress–strain curve and thermal conductivity of the composite material, finite-element analysis (FEA), in conjunction with the embedded fibre method (EFM), is used. Variable nanotube geometry, alignment and waviness are taken into account. First, a random morphology of a user-defined volume fraction of nanotubes is generated, and their properties are incorporated into the polymer matrix using the (...) EFM. Next, incremental and iterative FEA approaches are used for the determination of the nonlinear properties of the nanocomposite. For the determination of the electrical properties, a spanning network identification algorithm is used. First, a realistic nanotube morphology is generated from input parameters defined by the user. The spanning network algorithm then determines the connectivity between nanotubes in a representative volume element. Then, interconnected nanotube networks are converted to equivalent resistor circuits. Finally, Kirchhoff's current law is used in conjunction with FEA to solve for the voltages and currents in the system and thus calculate the effective electrical conductivity of the nanocomposite. The model accounts for electrical transport mechanisms such as electron hopping and simultaneously calculates percolation probability, identifies the backbone and determines the effective conductivity. Monte Carlo analysis of 500 random microstructures is performed to capture the stochastic nature of the fibre generation and to derive statistically reliable results. The models are validated by comparison with various experimental datasets reported in the recent literature. (shrink)
Monte Carlo simulations arrive at their results by introducing randomness, sometimes derived from a physical randomizing device. Nonetheless, we argue, they open no new epistemic channels beyond that already employed by traditional simulations: the inference by ordinary argumentation of conclusions from assumptions built into the simulations. We show that Monte Carlo simulations cannot produce knowledge other than by inference, and that they resemble other computer simulations in the manner in which they derive their conclusions. Simple examples of Monte (...)Carlo simulations are analysed to identify the underlying inferences. (shrink)
The rate equation approach is useful for semi-quantitatively simulating long-term processes of accumulation or recovery of lattice defects in crystalline materials upon irradiation or annealing. This approach has been developed and applied to a large number of systems, including 3D or 1D migrating self-interstitial atoms (SIAs) and 1D migrating SIA clusters. The dimensionality of the migration of mobile species significantly affects the forms of the reaction rate. For reactions related to 1D migrating SIAs and clusters, only their reactions with stationary (...) traps have been considered. However, the reactions between 1D migrating SIAs (or clusters) cannot be ignored, especially for processes in metals, in which the most stable configuration of an SIA is the crowdion, under electron and ion irradiations at comparatively high dose rate. In the present study, we use the object kinetic Monte Carlo (KMC) method to find the approximate form of the reaction rate between 1D migrating SIAs. For this purpose, we examine the average time for one SIA to encounter another SIA, in systems where the spatial distribution of SIAs is kept homogeneous, as a function of the concentration of SIAs. The approximate form of the reaction rate between 1D migrating SIAs primarily and effectively reflects the 2D migration process. In addition, it is shown that, in the systems composed of all reactive SIAs under annealing, the absolute value of the reaction rate by KMC becomes slightly lower than the solution of the derived form after longer times, due to the spatial correlation among SIAs. (shrink)
Shaftesbury señala la belleza de la teoría matemática y le asigna relevancia en el despliegue y en la estructura misma del pensamiento. Esta nota considera a la vez dicha reflexión y los asertos del matemático Gian-Carlo Rota acerca de tópicos análogos e intenta dilucidar, dentro de lo posible, ambas intuiciones.
We revisit one of the first quantum Monte Carlo methods using a combination of the Suzuki?Trotter transformation and Taylor series expansion for the XYZ Heisenberg chain with a magnetic field along the z-axis. We show a substantial gain in accuracy and computational time. This combination is especially useful for small magnetic fields and lower temperatures.
The essay examines both the dances and the dance notation of renowned nineteenth century choreographer Carlo Blasis. It looks in detail at Blasis major treatise The Code of Terpsichore in an effort to evaluate how Blasis linked a science of movement to a conception of the body oriented around the prevailing aesthetics informing all of the fine arts. Identifying Blasis as both a philosopher and a mechanist, this essay analyzes his approach to teaching basic ballet vocabulary, and in particular (...) the arabesque. Whereas Kleist, with his Marionettentheater, proposes the puppet as a figure of grace, located somewhere between animal and doll, Blasis brings together the movement science of mechanics and the descriptive theory of grace (as mimesis) in a poetics of the arabesque, a synthesis of elevation and evanescence, which we see when we conjure up pictures of nineteenth century Romantic ballet. (shrink)
A model of the ? to ? phase transformation in Ti, Zr and Hf alloys is proposed whereby the three-dimensional displacive transition is decomposed into one-dimensional and two-dimensional components. The one-dimensional component is postulated to be a linear displacive defect along ?111? closepacked rows of the b.c.c. structure, the two-dimensional component then consists of the cooperative ordering of neighbouring parallel linear defects in the (111) planes normal to the linear component. That the two-dimensional cooperative ordering of displaced row segments can (...) lead to a sharp phase transition has been demonstrated by a two-dimensional Monte Carlo simulation involving three types of symbols with nearest-neighbour interactions. Computer simulation exhibits characteristic two-domain ? structures which, along with the linear defect structure, appear to explain, at least qualitatively, observed electron and neutron diffraction patterns. It is tentatively suggested that the postulated linear defects play an important role in internal friction and in anomalous diffusion in certain b.c.c. metals. (shrink)