1,684 research outputs found

    Odor-driven attractor dynamics in the antennal lobe allow for simple and rapid olfactory pattern classification

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    The antennal lobe plays a central role for odor processing in insects, as demonstrated by electrophysiological and imaging experiments. Here we analyze the detailed temporal evolution of glomerular activity patterns in the antennal lobe of honeybees. We represent these spatiotemporal patterns as trajectories in a multidimensional space, where each dimension accounts for the activity of one glomerulus. Our data show that the trajectories reach odor-specific steady states (attractors) that correspond to stable activity patterns at about 1 second after stimulus onset. As revealed by a detailed mathematical investigation, the trajectories are characterized by different phases: response onset, steady-state plateau, response offset, and periods of spontaneous activity. An analysis based on support-vector machines quantifies the odor specificity of the attractors and the optimal time needed for odor discrimination. The results support the hypothesis of a spatial olfactory code in the antennal lobe and suggest a perceptron-like readout mechanism that is biologically implemented in a downstream network, such as the mushroom body

    Re-Offending by released Terrorist Prisoners:Separating Hype from Reality

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    Recent cases of attacks by released terrorist prisoners highlight issues around the risk of re-offending posed by former terrorist prisoners. What are the appropriate processes and systems for managing and risk assessing such individuals, and to what extent is rehabilitation possible in the context of terrorist offending? This Policy Brief will explore these and related issues to help inform wider discussion and debates on appropriate policy in this area. In this Policy Brief, the authors critically analyse the definition of ‘recidivism’, and demonstrate the need for a concrete operational definition before one is able to truly analyse recidivist activity. Following this, the authors discuss terrorist recidivism in a range of international contexts, ranging from Northern Ireland to Sri Lanka, the United States to Israel. By taking this broader perspective it allows the reader to gain a greater understanding of what factors related to recidivism rates may be context-specific, and which are universal

    Dimensions of Migrant Integration in Western Europe

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    The integration of immigrant minorities is a major concern for diverse societies - with major implications for the well-being of those affected, social cohesion and group relations, and economic and social progress. In this paper, we give a comprehensive description of long-term migrant integration in Western Europe to investigate theories of migrant assimilation and integration. We take a multidimensional approach, looking at 10 indicators measuring social, structural, political, civic and cultural integration. We take an innovative approach to measuring minority background by using two complementary measures: generational status, distinguishing first and second-generation migrants from the third and higher up 'natives,' and self-reported ancestry, separating those with autochthonous-only ancestry from those with various kinds of allochthonous ancestry. Using interaction effects between these measures, we can test whether generational change is faster or slower for some ethnic groups than for others, i.e. whether different groups integrate at differing speeds. Using the pooled samples of all Western European countries included in the European Social Survey rounds 7 and 8, we run multivariate regression analyses to estimate the effects of migrant background on the 10 indicators of integration. Compared to migrants with autochthonous ancestry, respondents of Middle Eastern, North African & Central Asian as well as Sub-Saharan African ancestry are less integrated on all dimensions of integration except the political and civic ones. The South & South-East Asian group is also substantially less assimilated socially and culturally, but not so much structurally. They are closely followed by the South East and East European groups, following the same pattern except that the latter are less integrated politically as well. We only find substantial interaction effects between ethnic group and migrant generation for two integration indicators, namely citizenship and homophobia, for which speed of integration thus appears to differ across ethnic groups. For all other indicators, integration speed does not appear to differ across ethnic groups, supporting straight line assimilation theory, with social integration in terms of interethnic friendship potentially rather following a 'bumpy-line' pattern

    Entropy and Temperature of a Static Granular Assembly

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    Granular matter is comprised of a large number of particles whose collective behavior determines macroscopic properties such as flow and mechanical strength. A comprehensive theory of the properties of granular matter, therefore, requires a statistical framework. In molecular matter, equilibrium statistical mechanics, which is founded on the principle of conservation of energy, provides this framework. Grains, however, are small but macroscopic objects whose interactions are dissipative since energy can be lost through excitations of the internal degrees of freedom. In this work, we construct a statistical framework for static, mechanically stable packings of grains, which parallels that of equilibrium statistical mechanics but with conservation of energy replaced by the conservation of a function related to the mechanical stress tensor. Our analysis demonstrates the existence of a state function that has all the attributes of entropy. In particular, maximizing this state function leads to a well-defined granular temperature for these systems. Predictions of the ensemble are verified against simulated packings of frictionless, deformable disks. Our demonstration that a statistical ensemble can be constructed through the identification of conserved quantities other than energy is a new approach that is expected to open up avenues for statistical descriptions of other non-equilibrium systems.Comment: 5 pages, 4 figure

    Product market competition, corporate governance and firm performance: An empirical analysis for Germany

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    Productivity growth has been slow in many continental European countries over the last few decades, especially in comparison with the United States. It has been argued that lack of product market competition and poor corporate governance are two of the main reasons for this phenomenon. However, predictions from theoretical models are far from unambiguous, and empirical evidence is sparse, in particular at the level of individual firms. In this paper, we aim to close this gap with an econometric analysis of firm performance in Germany. Based on a unique panel data set with detailed information on almost 400 manufacturing firms over the 1986-94 period, we find that firms operating in industries which are characterized by more intensive product market competition experience higher rates of productivity growth. We also find weak evidence for the notion that in Germany’s bank-based system of internal control, ownership concentration is harmful for productivity growth

    EVALUASI PELAKSANAAN PROGRAM PENGEMBANGAN KAWASAN MINAPOLITAN DENGAN MODEL CIPP (CONTEX, INPUT, PROCESS, PRODUCT) DI KOTA BITUNG

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    This study aims to evaluate the Implementation of Minapolitan Area Development Program with CIPP Model (Context, Input, Process, Product in Bitung City) This research was conducted from May until July 2016 in Bitung City The data collection method used is primary and secondary data. The analytical method used in this research is descriptive qualitative analysis which is used to clearly describe the condition of development of Minapolitan area in Bitung City Evaluation model used is CIPP Evaluation Model (Context, Input, Process, Product, Result) The result of the research is Context Evaluation (1) Based on the evaluation of the implementation context of the development program of Minapolitan area in Bitung City is very suitable if the City of Bitung stipulated by the decree of the minister of marine and fishery Number KEP.32 / MEN / 2010 because Bitung City meets the requirements of a region determined as gai area minapolitan one of which is a strategic location and natural resources available. (2) Based on input evaluais seen from several aspects, among others: (a) infrastructure aspect, (b) institutional aspect and regulation, (c) funding aspect, (3) Based on process evaluation, where the blue ocean port becomes the motto of the mover and the harbor continues to be developed to match the fishing port in the Philippines. (4) Based on product evaluation, the implementation of minapolitan program in Bitung City increases the volume and value of capture fisheries production in Bitung City

    Evaluation of single-nucleotide polymorphism imputation using random forests

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    Genome-wide association studies (GWAS) have helped to reveal genetic mechanisms of complex diseases. Although commonly used genotyping technology enables us to determine up to a million single-nucleotide polymorphisms (SNPs), causative variants are typically not genotyped directly. A favored approach to increase the power of genome-wide association studies is to impute the untyped SNPs using more complete genotype data of a reference population

    Role of histamine as a putative inhibitory transmitter in the honeybee antennal lobe

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    BACKGROUND: Odors are represented by specific spatio-temporal activity patterns in the olfactory bulb of vertebrates and its insect analogue, the antennal lobe. In honeybees inhibitory circuits in the AL are involved in the processing of odors to shape afferent odor responses. GABA is known as an inhibitory transmitter in the antennal lobe, but not all interneurons are GABAergic. Therefore we sought to analyze the functional role of the inhibitory transmitter histamine for the processing of odors in the honeybee AL. RESULTS: We optically recorded the representation of odors before, during and after histamine application at the input level (estimated from a compound signal), and at the output level (by selectively measuring the projection neurons). For both, histamine led to a strong and reversible reduction of odor-evoked responses. CONCLUSION: We propose that histamine, in addition to GABA, acts as an inhibitory transmitter in the honeybee AL and is therefore likely to play a role in odor processing
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