A little learning is a dangerous thing: an experimental demonstration of ignorance-driven inference

Studies of ignorance-driven decision making have been employed to analyse when ignorance should prove advantageous on theoretical grounds or else they have been employed to examine whether human behaviour is consistent with an ignorance-driven inference strategy (e. g., the recognition heuristic). In the current study we examine whether-under conditions where such inferences might be expected-the advantages that theoretical analyses predict are evident in human performance data. A single experiment shows that, when asked to make relative wealth judgements, participants reliably use recognition as a basis for their judgements. Their wealth judgements under these conditions are reliably more accurate when some of the target names are unknown than when participants recognize all of the names (a "less-is-more effect"). These results are consistent across a number of variations: the number of options given to participants and the nature of the wealth judgement. A basic model of recognition-based inference predicts these effects.

Deciding the price of fame

Previous studies of ignorance-driven decision-making have either analyzed when ignorance should prove advantageous on theoretical grounds, or else they have examined whether human behavior is consistent with an ignorance driven inference strategy (e.g., the recognition heuristic). The current study merges these research goals by examining whether – under conditions where ignorance driven inference might be expected – the type of advantages theoretical analyses predict are evident in human performance data. A single experiment shows that, when asked to make relative wealth judgments, participants reliably use recognition as a basis for their judgments. Their wealth judgments under these conditions are reliably more accurate when some of the target names are unknown than when participants recognize all the names (the “less-is-more effect”). these data are robust against a number of variations on the size of the pool from which participants have to choose and the nature of the wealth judgment.

Space-time multirate blind multiuser detection for synchronous DS/CDMA systems

This paper proposes the subspace-based space-time (ST) dual-rate blind linear detectors for synchronous DS/CDMA systems, which can be viewed as the ST extension of our previously presented purely temporal dual-rate blind linear detectors. The theoretical analyses on their performances are also carried out. Finally, the two-stage ST blind detectors are presented, which combine the adaptive purely temporal dual-rate blind MMSE filters with the non-adaptive beamformer. Their adaptive stages with parallel structure converge much faster than the corresponding adaptive ST dual-rate blind MMSE detectors, while having a comparable computational complexity to the latter.

Subspace-based blind adaptive multiuser detection for multirate DS/CDMA signals

The existing dual-rate blind linear detectors, which operate at either the low-rate (LR) or the high-rate (HR) mode, are not strictly blind at the HR mode and lack theoretical analysis. This paper proposes the subspace-based LR and HR blind linear detectors, i.e., bad decorrelating detectors (BDD) and blind MMSE detectors (BMMSED), for synchronous DS/CDMA systems. To detect an LR data bit at the HR mode, an effective weighting strategy is proposed. The theoretical analyses on the performance of the proposed detectors are carried out. It has been proved that the bit-error-rate of the LR-BDD is superior to that of the HR-BDD and the near-far resistance of the LR blind linear detectors outperforms that of its HR counterparts. The extension to asynchronous systems is also described. Simulation results show that the adaptive dual-rate BMMSED outperform the corresponding non-blind dual-rate decorrelators proposed by Saquib, Yates and Mandayam (see Wireless Personal Communications, vol. 9, p.197-216, 1998).

Review of R&D progress and practical application of the solar photovoltaic/thermal (PV/T) technologies

In this paper, the global market potential of solar thermal, photovoltaic (PV) and combined photovoltaic/thermal (PV/T) technologies in current time and near future was discussed. The concept of the PV/T and the theory behind the PV/T operation were briefly introduced, and standards for evaluating technical, economic and environmental performance of the PV/T systems were addressed. A comprehensive literature review into R&D works and practical application of the PV/T technology was illustrated and the review results were critically analysed in terms of PV/T type and research methodology used. The major features, current status, research focuses and existing difficulties/barriers related to the various types of PV/T were identified. The research methods, including theoretical analyses and computer simulation, experimental and combined experimental/theoretical investigation, demonstration and feasibility study, as well as economic and environmental analyses, applied into the PV/T technology were individually discussed, and the achievement and problems remaining in each research method category were described. Finally, opportunities for further work to carry on PV/T study were identified. The review research indicated that air/water-based PV/T systems are the commonly used technologies but their thermal removal effectiveness is lower. Refrigerant/heat-pipe-based PV/Ts, although still in research/laboratory stage, could achieve much higher solar conversion efficiencies over the air/water-based systems. However, these systems were found a few technical challenges in practice which require further resolutions. The review research suggested that further works could be undertaken to (1) develop new feasible, economic and energy efficient PV/T systems; (2) optimise the structural/geometrical configurations of the existing PV/T systems; (3) study long term dynamic performance of the PV/T systems; (4) demonstrate the PV/T systems in real buildings and conduct the feasibility study; and (5) carry on advanced economic and environmental analyses. This review research helps finding the questions remaining in PV/T technology, identify new research topics/directions to further improve the performance of the PV/T, remove the barriers in PV/T practical application, establish the standards/regulations related to PV/T design and installation, and promote its market penetration throughout the world.

An infrared desert dust index for the Along-Track Scanning Radiometers

A new aerosol index for the Along-Track Scanning Radiometers (ATSRs) is presented that provides a means to detect desert dust contamination in infrared SST retrievals. The ATSR Saharan dust index (ASDI) utilises only the thermal infrared channels and may therefore be applied consistently to the entire ATSR data record (1991 to present), for both day time and night time observations. The derivation of the ASDI is based on a principal component (PC) analysis (PCA) of two unique pairs of channel brightness temperature differences (BTDs). In 2-D space (i.e. BTD vs BTD), it is found that the loci of data unaffected by aerosol are confined to a single axis of variability. In contrast, the loci of aerosol-contaminated data fall off-axis, shifting in a direction that is approximately orthogonal to the clear-sky axis. The ASDI is therefore defined to be the second PC, where the first PC accounts for the clear-sky variability. The primary ASDI utilises the ATSR nadir and forward-view observations at 11 and 12 μm (ASDI2). A secondary, three-channel nadir-only ASDI (ASDI3) is also defined for situations where data from the forward view are not available. Empirical and theoretical analyses suggest that ASDI is well correlated with aerosol optical depth (AOD: correlation r is typically > 0.7) and provides an effective tool for detecting desert mineral dust. Overall, ASDI2 is found to be more effective than ASDI3, with the latter being sensitive only to very high dust loading. In addition, use of ASDI3 is confined to night time observations as it relies on data from the 3.7 μm channel, which is sensitive to reflected solar radiation. This highlights the benefits of having data from both a nadir- and a forward-view for this particular approach to aerosol detection.

Phytoplankton–zooplankton dynamics in the ‘presence’ or ‘absence’ of toxic phytoplankton

The inhibitory effects of toxin-producing phytoplankton (TPP) on zooplankton modulate the dynamics of marine plankton. In this article, we employ simple mathematical models to compare theoretically the dynamics of phytoplankton–zooplankton interaction in situations where the TPP are present with those where TPP are absent. We consider two sets of three-component interaction models: one that does not include the effect of TPP and the other that does. The negative effects of TPP on zooplankton is described by a non-linear interaction term. Extensive theoretical analyses of the models have been performed to understand the qualitative behaviour of the model systems around every possible equilibria. The results of local-stability analysis and numerical simulations demonstrate that the two model-systems differ qualitatively with regard to oscillations and stability. The model system that does not include TPP is asymptotically stable around the coexisting equilibria, whereas, the system that includes TPP oscillates for a range of parametric values associated with toxin-inhibition rate and competition coefficients. Our analysis suggests that the qualitative dynamics of the plankton–zooplankton interactions are very likely to alter due to the presence of TPP species, and therefore the effects of TPP should be considered carefully while modelling plankton dynamics.

FORCED CONVECTION TO LAMINAR FLOW OF LIQUID EGG YOLK IN CIRCULAR AND ANNULAR DUCTS

The steady-state heat transfer in laminar flow of liquid egg yolk - an important pseudoplastic fluid food - in circular and concentric annular ducts was experimentally investigated. The average convection heat transfer coefficients, determined by measuring temperatures before and after heating sections with constant temperatures at the tube wall, were used to obtain simple new empirical expressions to estimate the Nusselt numbers for fully established flows at the thermal entrance of the considered geometries. The comparisons with existing correlations for Newtonian and non-Newtonian fluids resulted in excellent agreement. The main contribution of this work is to supply practical and easily applicable correlations, which are, especially for the case of annulus, rather scarce and extensively required in the design of heat transfer operations dealing with similar shear-thinning products. In addition, the experimental results may support existing theoretical analyses.

Confinement and surface effects in B and P doping of silicon nanowires

Several experimental groups have achieved effective n- and p-type doping of silicon nanowires (SiNWs). However, theoretical analyses on ultrathin SiNWs suggest that dopants tend to segregate to their surfaces, where they would combine with defects such as dangling bonds (DB), becoming electronically inactive. Using fully ab initio calculations, we show that the differences in formation energies among surface and core substitutional sites decrease rapidly as the diameters of the wires increase, indicating that the dopants will be uniformly distributed. Moreover, occurrence of the electronically inactive impurity/DB complex rapidly becomes less frequent for NWs of larger diameters. We also show that the high confinement in the ultrathin SiNWs causes the impurity levels to be deeper than in the silicon bulk, but our results indicate that for NWs of diameters larger than approximately 3 nm the impurity levels recover bulk characteristics. Finally, we show that different surfaces will lead to different dopant properties in the gap.

Estratégia empresarial e modos de busca de novos negócios - uma análise das estratégias de busca de novos negócios em empresas brasileiras

O objetivo deste trabalho é a investigação de como as empresas brasileiras, no contexto nacional, empreendem a busca de novas oportunidades de negócios, identificando quais os fatores que mais claramente influenciam este comportamento. Este trabalho se estruturou a partir da operacionalização do modelo de modelo de busca estratégica e interpretação ambiental proposto por Richard Daft e Karl Weick em 1984. Foram para tanto realizadas análises estatísticas e teóricas a partir de uma pesquisa empírica realizada entre 182 empresas brasileiras.

Efeito da eleição do candidato da oposição sobre a apresentação e aprovação de projetos do prefeito na Câmara

Este trabalho tem por objetivo analisar o efeito de se eleger um candidato da oposição em eleições municipais sobre a apresentação e aprovação de projetos do prefeito então eleito na câmara de vereadores, no ano subsequente. Tal questão diz respeito à vantagem, para os munícipes, de optar pela alternância de poder em detrimento da reeleição, bem como à relação entre o novo representante do executivo e os vereadores. Dialoga-se, assim, com uma literatura político-eleitoral pródiga na análise dos fatores que favorecem a reeleição, mas que pouco se debruçou sobre as consequências futuras da alternância de poder. Igualmente, contribui-se com um embasamento econométrico para as discussões fomentadas a nível teórico a respeito das relações entre os poderes no município. A metodologia empregada se baseia na técnica de regressões descontínuas ou RDD para tratamento quase-experimental dos dados coletados no TSE e no Censo Legislativo de 2005. A partir da análise dos dados, e com significância moderada, argumenta-se que quando o prefeito eleito é da oposição ele tende a apresentar menos projetos à câmara em seu primeiro ano de mandato, mas recebe acolhida proporcionalmente mais favorável por parte dos vereadores.

Adolescentes e policiais na orla marítima de Natal/RN: um estudo sobre representações sociais a propósito do turismo sexual

This dissertation approaches the children's sexual tourism and adolescents in the seafront of Natal/RN, in the Childhood and youth perspective and military policeman. It analyzes the sexual tourism as development source and of exploration, analyzing your dimensions in reality of Natal/RN, taking as empiric universe your urban seafront and the Independent Company of Tourist Protection, through the cash military policeman. That discussion contemplates theoretical elements, ruled mainly in Pierre Bourdieu theoretical analyses and Michel Foucault, ally to an empiric picture that possesses great specific as the Praia do Meio, Ponta Negra, Alagamar and Praia da Redinha, where they were applied techniques of observation no systematic, rising and bibliographical revision and glimpses semi-structured the white public composed of twenty-five military policemen close to and of fifteen children and adolescents. Along the text several discussions they are accomplished aiming at the understanding of the reality of the tourism-sexual childhood-juvenile, through the study on the body, of the sexuality, of the habitus, of the stigmatization, of the public safety and of the paper military policeman in this context. For the understanding of this reality the Subject's Bus of military policemen speech was proceeded and of children and adolescents, aiming at the understanding that each segment possesses of the other, and the analysis of the speech policeman military produce the perception of considering the childhood and youth that practices the sex tourism, as people originating from of families no restructured and that live social inequalities; while the other segment notices the military policeman as arbitrary and violent system.

Rodando a bolsinha: dinheiro e relações de prostituição

In this work a series of discussions is made on the relationship between money and prostitution in a way of overcoming its merely economic aspects, in the perception of both being social, cultural and historical phenomena, and taking them as symbols, whose study aids to unveil the reality. In this context it is looked for revealing its forms and contents to make it possible to understand them beyond the rationality, calculability and mathematical elements presents in them; beyond apparentness, taking them in their complexity. The discussions encompass theoretical elements, based especially on Georg Simmel s theoretical analyses, allied to a specific empirical frame that regards the life experience of the women of Praia do Meio, pedaço of the city of Natal-RN-Brazil, where the data were collected from. Fundamentally, prostitution is perceived as an exchange activity, which is not depleted in the economic elements, but, contrarily, starts on them and surpasses them in diverse aspects. It deals about a money-mediated relationship between human beings that possesses in itself a full complexity, which demands an accurate and keen attention to be comprehended. Since money has transformed the world and the men and women in it, the discussions in the text are conducted in a direction to attempt to encircle and understand the relationship between money and prostitution. Prostitution, in turn, aids to understand such a transformation as it is also a symbol of our times and it makes us to face the true essence of our society: the transformation of human beings into merchandise, into negotiable objects. In the money-based society it is possible to picture the phenomenon of double prostitution: negotiation of the human being, through labor, and negotiation of sex, the last being dramatically stigmatized and the former strongly encouraged. This may be demonstrating that the paid sex is, in the money-ruled society, a limit of commercialization, widely accepted provided it is camouflaged and surrounded by an aura of sensuality and legitimacy

Forced convection to laminar flow of liquid egg yolk in circular and annular ducts

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sistemas híbridos para mitigação de harmônicos: modelagem e estudos experimentais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)