Stimulus Simplification and Object Representation: A Modeling Study

Tsunoda et al. (2001) recently studied the nature of object representation in monkey inferotemporal cortex using a combination of optical imaging and extracellular recordings. In particular, they examined IT neuron responses to complex natural objects and "simplified" versions thereof. In that study, in 42% of the cases, optical imaging revealed a decrease in the number of activation patches in IT as stimuli were "simplified". However, in 58% of the cases, "simplification" of the stimuli actually led to the appearance of additional activation patches in IT. Based on these results, the authors propose a scheme in which an object is represented by combinations of active and inactive columns coding for individual features. We examine the patterns of activation caused by the same stimuli as used by Tsunoda et al. in our model of object recognition in cortex (Riesenhuber 99). We find that object-tuned units can show a pattern of appearance and disappearance of features identical to the experiment. Thus, the data of Tsunoda et al. appear to be in quantitative agreement with a simple object-based representation in which an object's identity is coded by its similarities to reference objects. Moreover, the agreement of simulations and experiment suggests that the simplification procedure used by Tsunoda (2001) is not necessarily an accurate method to determine neuronal tuning.

Financial Information Mediation: A Case Study of Standards Integration for Electronic Bill Presentment and Payment Using the COIN Mediation Technology

Each player in the financial industry, each bank, stock exchange, government agency, or insurance company operates its own financial information system or systems. By its very nature, financial information, like the money that it represents, changes hands. Therefore the interoperation of financial information systems is the cornerstone of the financial services they support. E-services frameworks such as web services are an unprecedented opportunity for the flexible interoperation of financial systems. Naturally the critical economic role and the complexity of financial information led to the development of various standards. Yet standards alone are not the panacea: different groups of players use different standards or different interpretations of the same standard. We believe that the solution lies in the convergence of flexible E-services such as web-services and semantically rich meta-data as promised by the semantic Web; then a mediation architecture can be used for the documentation, identification, and resolution of semantic conflicts arising from the interoperation of heterogeneous financial services. In this paper we illustrate the nature of the problem in the Electronic Bill Presentment and Payment (EBPP) industry and the viability of the solution we propose. We describe and analyze the integration of services using four different formats: the IFX, OFX and SWIFT standards, and an example proprietary format. To accomplish this integration we use the COntext INterchange (COIN) framework. The COIN architecture leverages a model of sources and receivers’ contexts in reference to a rich domain model or ontology for the description and resolution of semantic heterogeneity.

Scitable - Learn Science with Nature Education

Scitable is an open online teaching/learning portal combining high quality educational articles authored by editors at NPG with technology-based community features to fuel a global exchange of scientific insights, teaching practices, and study resources. Scitable currently contains articles in the field of genetics, and is intended for college undergraduate faculty and students. Future plans involve extension of Scitable to other fields within the life sciences, as well as to other audiences. Scitable brings together a library of scientific overviews with a worldwide community of scientists, researchers, teachers and students. Nature Education is a new division of Nature Publishing Group devoted to facilitating high quality, innovative, accessible science education in all countries of the world.

On blame-freeness and reciprocity: an experimental study

The theory of reciprocity is predicated on the assumption that people are willing to reward nice or kind acts and to punish unkind ones. This assumption raises the question as to how to define kindness. In this paper we offer a new definition of kindness that we call “blame-freeness.” Put most simply, blame-freeness states that in judging whether player i has been kind or unkind to player j in a social situation, player j would have to put himself in the strategic position of player i, while retaining his preferences, and ask if he would have acted in a manner that was worse than i did under identical circumstances. If j would have acted in a more unkind manner than i acted, then we say that j does not blame i for his behavior. If, however, j would have been nicer than i was, then we say that “j blames i” for his actions (i’s actions were blameworthy). We consider this notion a natural, intuitive and empirically relevant way to explain the motives of people engaged in reciprocal behavior. After developing the conceptual framework, we then test this concept in a laboratory experiment involving tournaments and find significant support for the theory.

Electronic couplings and on-site energies for hole transfer in DNA: systematic quantum mechanical/molecular dynamic study

The electron hole transfer (HT) properties of DNA are substantially affected by thermal fluctuations of the π stack structure. Depending on the mutual position of neighboring nucleobases, electronic coupling V may change by several orders of magnitude. In the present paper, we report the results of systematic QM/molecular dynamic (MD) calculations of the electronic couplings and on-site energies for the hole transfer. Based on 15 ns MD trajectories for several DNA oligomers, we calculate the average coupling squares 〈 V2 〉 and the energies of basepair triplets X G+ Y and X A+ Y, where X, Y=G, A, T, and C. For each of the 32 systems, 15 000 conformations separated by 1 ps are considered. The three-state generalized Mulliken-Hush method is used to derive electronic couplings for HT between neighboring basepairs. The adiabatic energies and dipole moment matrix elements are computed within the INDO/S method. We compare the rms values of V with the couplings estimated for the idealized B -DNA structure and show that in several important cases the couplings calculated for the idealized B -DNA structure are considerably underestimated. The rms values for intrastrand couplings G-G, A-A, G-A, and A-G are found to be similar, ∼0.07 eV, while the interstrand couplings are quite different. The energies of hole states G+ and A+ in the stack depend on the nature of the neighboring pairs. The X G+ Y are by 0.5 eV more stable than X A+ Y. The thermal fluctuations of the DNA structure facilitate the HT process from guanine to adenine. The tabulated couplings and on-site energies can be used as reference parameters in theoretical and computational studies of HT processes in DNA

Predictors of knowledge creation performance. A quantitative qualitative comparative study of European doctorandi

Aquesta tesi forma part d'un projecte destinat a predir el rendiment acadèmic dels estudiants de doctorat portat a terme per l'INSOC (International Network on Social Capital and Performance). El grup de recerca INSOC està format per les universitats de Girona (Espanya), Ljubljana (Eslovènia), Giessen (Alemanya) i Ghent (Bèlgica). El primer objectiu d'aquesta tesi és desenvolupar anàlisis quantitatius comparatius sobre el rendiment acadèmic dels estudiants de doctorat entre Espanya, Eslovènia i Alemanya a partir dels resultats individuals del rendiment acadèmic obtinguts de cada una de les universitats. La naturalesa internacional del grup de recerca implica la recerca comparativa. Vam utilitzar variables personal, actitudinals i de xarxa per predir el rendiment. El segon objectiu d'aquesta tesi és entendre de manera qualitativa perquè les variables de xarxa no ajuden quantitativament a predir el rendiment a la universitat de Girona (Espanya). En el capítol 1, definim conceptes relacionats amb el rendiment i donam un llistat de cada una de les variables independents (variables de xarxa, personals i actitudinals), resumint la lliteratura. Finalment, explicam com s'organitzen els estudis de doctorat a cada un dels diferents països. A partir d'aquestes definicions teòriques, en els pròxims capítols, primer presentarem els qüestionaris utilitzats a Espanya, Eslovènia i Alemanya per mesurar aquests diferents tipus de variables. Després, compararem les variables que són relevants per predir el rendiment dels estudiants de doctorat a cada país. Després d'això, fixarem diferents models de regressió per predir el rendiment entre països. En tots aquests models les variables de xarxa fallen a predir el rendiment a la Universitat de Girona. Finalment, utilitzem estudis qualitatius per entendre aquests resultats inesperats. En el capítol 2, expliquem com hem dissenyat i conduït els qüestionaris en els diferents països amb l'objectiu d'explicar el rendiment dels estudiants de doctorat obtinguts a Espanya, Eslovènia i Alemanya. En el capítol 3, cream indicadors comparables però apareixen problemes de comparabilitat en preguntes particulars a Espanya, Eslovènia i Alemanya. En aquest capítol expliquem com utilitzem les variables dels tres països per crear indicadors comparables. Aquest pas és molt important perquè el principal objectiu del grup de recerca INSOC és comparar el rendiment dels estudiants de doctorat entre els diferents països. En el capítol 4 comparem models de regressió obtinguts de predir el rendiment dels estudiants de doctorat a les universitats de Girona (Espanya) i Eslovènia. Les variables són característiques dels grups de recerca dels estudiants de doctorat enteses com una xarxa social egocèntrica, característiques personals i actitudinals dels estudiants de doctorat i algunes carecterístiques dels directors. Vam trobar que les variables de xarxa egocèntriques no predien el rendiment a la Universitat de Girona. En el capítol 5, comparem dades eslovenes, espanyoles i alemnayes, seguint la metodologia del capítol 4. Concluïm que el cas alemany és molt diferent. El poder predictiu de les variables de xarxa no millora. En el capítol 6 el grup de recerca dels estudiants de doctorat és entès com una xarxa duocèntrica (Coromina et al., 2008), amb l'objectiu d'obtendre informació de la relació mútua entre els estudiants i els seus directors i els contactes d'ambdós amb els altres de la xarxa. La inclusió de la xarxa duocèntrica no millora el poder predictiu del model de regressió utilitzant les variales egocèntriques de xarxa. El capítol 7 pretèn entendre perquè les variables de xarxa no predeixen el rendiment a la Universitat de Girona. Utilitzem el mètode mixte, esperant que l'estudi qualitatiu pugui cobrir les raons de perquè la qualitat de la xarxa falla en la qualitat del treball dels estudiants. Per recollir dades per l'estudi qualitatiu utilitzem entrevistes en profunditat.

Magnitude of climate variability during middle Pliocene warmth: a palaeoclimate modelling study

The nature and magnitude of climatic variability during the period of middle Pliocene warmth (ca 3.29–2.97 Ma) is poorly understood. We present a suite of palaeoclimate modelling experiments incorporating an advanced atmospheric general circulation model (GCM), coupled to a Q-flux ocean model for 3.29, 3.12 and 2.97 Ma BP. Astronomical solutions for the periods in question were derived from the Berger and Loutre BL2 astronomical solution. Boundary conditions, excluding sea surface temperatures (SSTs) which were predicted by the slab-ocean model, were provided from the USGS PRISM2 2°×2° digital data set. The model results indicate that little annual variation (0.5°C) in SSTs, relative to a ‘control’ experiment, occurred during the middle Pliocene in response to the altered orbital configurations. Annual surface air temperatures also displayed little variation. Seasonally, surface air temperatures displayed a trend of cooler temperatures during December, January and February, and warmer temperatures during June, July and August. This pattern is consistent with altered seasonality resulting from the prescribed orbital configurations. Precipitation changes follow the seasonal trend observed for surface air temperature. Compared to present-day, surface wind strength and wind stress over the North Atlantic, North Pacific and Southern Ocean remained greater in each of the Pliocene experiments. This suggests that wind-driven gyral circulation may have been consistently greater during the middle Pliocene. The trend of climatic variability predicted by the GCM for the middle Pliocene accords with geological data. However, it is unclear if the model correctly simulates the magnitude of the variation. This uncertainty is derived from, (a) the relative insensitivity of the GCM to perturbation in the imposed boundary conditions, (b) a lack of detailed time series data concerning changes to terrestrial ice cover and greenhouse gas concentrations for the middle Pliocene and (c) difficulties in representing the effects of ‘climatic history’ in snap-shot GCM experiments.

Putting the pieces back together again: an illustration of the problem of interpreting development indicators using an African case study

Indicators are commonly recommended as tools for assessing the attainment of development, and the current vogue is for aggregating a number of indicators together into a single index. It is claimed that such indices of development help facilitate maximum impact in policy terms by appealing to those who may not necessarily have technical expertise in data collection, analysis and interpretation. In order to help counter criticisms of over-simplification, those advocating such indices also suggest that the raw data be provided so as to allow disaggregation into component parts and hence facilitate a more subtle interpretation if a reader so desires. This paper examines the problems involved with interpreting indices of development by focusing on the United Nations Development Programmes (UNDP) Human Development Index (HDI) published each year in the Human Development Reports (HDRs). The HDI was intended to provide an alternative to the more economic based indices, such as GDP, commonly used within neo-liberal development agendas. The paper explores the use of the HDI as a gauge of human development by making comparisons between two major political and economic communities in Africa (ECOWAS and SADC). While the HDI did help highlight important changes in human development as expressed by the HDI over 10 years, it is concluded that the HDI and its components are difficult to interpret as methodologies have changed significantly and the 'averaging' nature of the HDI could hide information unless care is taken. The paper discusses the applicability of alternative models to the HDI such as the more neo-populist centred methods commonly advocated for indicators of sustainable development. (C) 2003 Elsevier Ltd. All rights reserved.

Evaluating explanations about drug prescriptions: effects of varying the nature of information about side effects and its relative position in explanations

This study evaluates computer-generated written explanations about drug prescriptions that are based on an analysis of both patient and doctor informational needs. Three experiments examine the effects of varying the type of information given about the possible side effects of the medication, and the order of information within the explanation. Experiment 1 investigated the effects of these two factors on people's ratings of how good they consider the explanations to be and of their perceived likelihood of taking the medication, as well as on their memory for the information in the explanation. Experiment 2 further examined the effects of varying information about side effects by separating out the contribution of number and severity of side effects. It was found that participants in this study did not “like” explanations that described severe side effects, and also judged that they would be less likely to take the medication if given such explanations. Experiment 3 therefore investigated whether information about severe side effects could be presented in such a way as to increase judgements of how good explanations are thought to be, as well as the perceived likelihood of adherence. The results showed some benefits of providing additional explanatory information.

Children's lives, children's futures: A study of children starting secondary school

This title presents a fascinating analysis of how children in their first year of high school feel about their schools, its place in their lives and its role in their futures. This highly topical monograph focuses on how children in their first year of high school feel about school, its place in their lives and its role in their futures. The theoretical context of the study is the focus in educational studies on children's voice and children's active role in education, together with the focus in the sociology of childhood on children as active constructors of their lives and childhood as a subject of serious study. The importance of young people's life plans and the alignment between education and ambitions was recognized in the Sloan Foundation study of American teenagers. In many Western societies there is concern that children from less advantaged social backgrounds have limited aspirations, and are disproportionately unlikely to go to university. This book is highly relevant to understanding the nature of children's engagement with education, the choices and constraints they experience and the reasons some young people fail to take advantage of educational opportunities. "Continuum Studies in Educational Research" (CSER) is a major new series in the field of educational research. Written by experts and scholars for experts and scholars, this ground-breaking series focuses on research in the areas of comparative education, history, lifelong learning, philosophy, policy, post-compulsory education, psychology and sociology. Based on cutting edge research and written with lucidity and passion, the CSER series showcases only those books that really matter in education - studies that are major, that will be remembered for having made a difference.

Implementation of a Bayesian design in a dose-escalation study of an experimental agent in healthy volunteers

Bayesian decision procedures have recently been developed for dose escalation in phase I clinical trials concerning pharmacokinetic responses observed in healthy volunteers. This article describes how that general methodology was extended and evaluated for implementation in a specific phase I trial of a novel compound. At the time of writing, the study is ongoing, and it will be some time before the sponsor will wish to put the results into the public domain. This article is an account of how the study was designed in a way that should prove to be safe, accurate, and efficient whatever the true nature of the compound. The study involves the observation of two pharmacokinetic endpoints relating to the plasma concentration of the compound itself and of a metabolite as well as a safety endpoint relating to the occurrence of adverse events. Construction of the design and its evaluation via simulation are presented.

Low genetic diversity in a marine nature reserve: re-evaluating diversity criteria in reserve design

Little consideration has been given to the genetic composition of populations associated with marine reserves, as reserve designation is generally to protect specific species, communities or habitats. Nevertheless, it is important to conserve genetic diversity since it provides the raw material for the maintenance of species diversity over longer, evolutionary time-scales and may also confer the basis for adaptation to environmental change. Many current marine reserves are small in size and isolated to some degree (e.g. sea loughs and offshore islands). While such features enable easier management, they may have important implications for the genetic structure of protected populations, the ability of populations to recover from local catastrophes and the potential for marine reserves to act as sources of propagules for surrounding areas. Here, we present a case study demonstrating genetic differentiation, isolation, inbreeding and reduced genetic diversity in populations of the dogwhelk Nucella lapillus in Lough Hyne Marine Nature Reserve (an isolated sea lough in southern Ireland), compared with populations on the local adjacent open coast and populations in England, Wales and France. Our study demonstrates that this sea lough is isolated from open coast populations, and highlights that there may be long-term genetic consequences of selecting reserves on the basis of isolation and ease of protection.

The photodimerisation of the alpha- and beta-forms of trans-cinnamic acid: a study of single crystals by vibrational microspectroscopy

Infrared and Raman microspectroscopy have been used to follow the photodimerisation reactions of single crystals, the alpha- and beta-forms of trans-cinnamic acid. This approach allows the starting materials and products -alpha-truxillic acid that has C-i symmetry and beta-truxinic acid, which has C-s symmetry-to be identified. It also allows the topotactic nature of the reaction to be confirmed. Attempts to produce the poorly-defined unreactive gamma-form of trans-cinnamic acid resulted only in a mixture of the alpha- and beta-forms. The findings suggest a wide role for these spectroscopic methods in monitoring solid-state organic reactions. (C) 2002 Elsevier Science B.V. All rights reserved.

Crystallization in poly(L-lactide)-b-poly(epsilon-caprolactone) double crystalline diblock copolymers: a study using X-ray scattering, differential scanning calorimetry, and polarized optical microscopy

The crystallization of well-defined poly(L-lactide)-b-poly(epsilon-caprolactone) diblock copolymers, PLLA-b-PCL, was investigated by time-resolved X-ray techniques, polarized optical microscopy (POM), and differential scanning calorimetry (DSC). Two compositions were studied that contained 44 and 60 wt % poly(L-lactide), PLLA (they are referred to as (L44C5614)-C-11 and (L60C409)-C-12, respectively, with the molecular weight of each block in kg/mol as superscript). The copolymers were found to be initially miscible in the melt according to small-angle X-ray scattering measurements (SAXS). Their thermal behavior was also indicative of samples whose crystallization proceeds from a mixed melt. Sequential isothermal crystallization from the melt at 100 degreesC (for 30 min) and then at 30 degreesC (for 15 min) was measured. At 100 degreesC only the PLLA block is capable of crystallization, and its crystallization kinetics was followed by both WAXS and DSC; comparable results were obtained that indicated an instantaneous nucleation with three-dimensional superstructures (Avrami index of approximately 3). The spherulitic nature of the superstructure was confirmed by POM. When the temperature was decreased to 30 degreesC, the PCL block was able to crystallize within the PLLA negative spherulites (with an Avrami index of 2, as opposed to 3 in homo-PCL), and its crystallization rate was much slower than an equivalent homo-PCL. Time-resolved SAXS experiments in (L60C409)-C-12 revealed an initial melt mixed morphology at 165 degreesC that upon cooling transformed into a transient microphase-separated lamellar structure prior to crystallization at 100 degreesC.

Gas-solid reactions of single crystals: a study of the reaction of bromine with single crystals of trans-cinnamic acid and a range of its derivatives by infrared and Raman microspectroscopy

Single crystals of trans-cinnamic acid and of a range of derivatives of this compound containing halogen substituents on the aromatic ring have been reacted with 165 Torr pressure of bromine vapour in a sealed desiccator at 20 degrees C for 1 week. Infrared and Raman microspectroscopic examination of the crystals shows that bromination of the aliphatic double bond, but not of the aromatic ring, has occurred. It is demonstrated also that the reaction is truly gas-solid in nature. A time-dependent study of these reactions shows that they do not follow a smooth diffusion-controlled pathway. Rather the reactions appear to be inhomogeneous and to occur at defects within the crystal. The reaction products are seen to flake from the surface of the crystal. It is shown, therefore, that these are not single crystal to single crystal transitions, as have been observed previously for the photodimerisation of trans-cinnamic acid and several of its derivatives. It is shown that there are no by-products of the reaction and that finely ground samples react to form the same products as single crystals.