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Sample records for metalloproteinase-mediated context-dependent function

  1. Predicting invasive species impacts: a community module functional response approach reveals context dependencies.

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    Paterson, Rachel A; Dick, Jaimie T A; Pritchard, Daniel W; Ennis, Marilyn; Hatcher, Melanie J; Dunn, Alison M

    2015-03-01

    Predatory functional responses play integral roles in predator-prey dynamics, and their assessment promises greater understanding and prediction of the predatory impacts of invasive species. Other interspecific interactions, however, such as parasitism and higher-order predation, have the potential to modify predator-prey interactions and thus the predictive capability of the comparative functional response approach. We used a four-species community module (higher-order predator; focal native or invasive predators; parasites of focal predators; native prey) to compare the predatory functional responses of native Gammarus duebeni celticus and invasive Gammarus pulex amphipods towards three invertebrate prey species (Asellus aquaticus, Simulium spp., Baetis rhodani), thus, quantifying the context dependencies of parasitism and a higher-order fish predator on these functional responses. Our functional response experiments demonstrated that the invasive amphipod had a higher predatory impact (lower handling time) on two of three prey species, which reflects patterns of impact observed in the field. The community module also revealed that parasitism had context-dependent influences, for one prey species, with the potential to further reduce the predatory impact of the invasive amphipod or increase the predatory impact of the native amphipod in the presence of a higher-order fish predator. Partial consumption of prey was similar for both predators and occurred increasingly in the order A. aquaticus, Simulium spp. and B. rhodani. This was associated with increasing prey densities, but showed no context dependencies with parasitism or higher-order fish predator. This study supports the applicability of comparative functional responses as a tool to predict and assess invasive species impacts incorporating multiple context dependencies. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

  2. Differential surface phenotype and context-dependent reactivity of functionally diverse NKT cells.

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    Cameron, Garth; Godfrey, Dale I

    2018-03-05

    Natural Killer T (NKT) cells are a functionally diverse population that recognizes lipid-based antigens in association with the antigen-presenting molecule CD1d. Here, we define a technique to separate the functionally distinct thymic NKT1, NKT2 and NKT17 cell subsets by their surface expression of CD278 (ICOS) and the activation-associated glycoform of CD43, enabling the investigation of subset-specific effector-functions. We report that all three subsets express the transcription factor GATA-3 and the potential to produce IL-4 and IL-10 following activation. This questions the notion that NKT2 cells are the predominant source of IL-4 within the NKT cell pool, and suggests that IL-10-production may be more indicative of NKT cell plasticity than the existence of a distinct regulatory lineage or subset. We also show that many NKT17 cells are CD4 + and are biased toward Vβ8.3 TCR gene usage. Lastly, we demonstrate that the toll-like receptor (TLR) ligand lipopolysaccharide (LPS) can induce a NKT17 cell-biased response, even in the absence of exogenous antigen, and that combining LPS with α-GalCer resulted in enhanced IL-17A-production, and reduced levels of the immunosuppressive cytokine IL-10. This study provides a novel means to examine the context-dependent reactivity of the functionally heterogeneous NKT cell population and provides important new insight into the functional biology of these subsets. © 2018 Australasian Society for Immunology Inc.

  3. Context-Dependent Functional Divergence of the Notch Ligands DLL1 and DLL4 In Vivo.

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    Kristina Preuße

    2015-06-01

    Full Text Available Notch signalling is a fundamental pathway that shapes the developing embryo and sustains adult tissues by direct communication between ligand and receptor molecules on adjacent cells. Among the ligands are two Delta paralogues, DLL1 and DLL4, that are conserved in mammals and share a similar structure and sequence. They activate the Notch receptor partly in overlapping expression domains where they fulfil redundant functions in some processes (e.g. maintenance of the crypt cell progenitor pool. In other processes, however, they appear to act differently (e.g. maintenance of foetal arterial identity raising the questions of how similar DLL1 and DLL4 really are and which mechanism causes the apparent context-dependent divergence. By analysing mice that conditionally overexpress DLL1 or DLL4 from the same genomic locus (Hprt and mice that express DLL4 instead of DLL1 from the endogenous Dll1 locus (Dll1Dll4ki, we found functional differences that are tissue-specific: while DLL1 and DLL4 act redundantly during the maintenance of retinal progenitors, their function varies in the presomitic mesoderm (PSM where somites form in a Notch-dependent process. In the anterior PSM, every cell expresses both Notch receptors and ligands, and DLL1 is the only activator of Notch while DLL4 is not endogenously expressed. Transgenic DLL4 cannot replace DLL1 during somitogenesis and in heterozygous Dll1Dll4ki/+ mice, the Dll1Dll4ki allele causes a dominant segmentation phenotype. Testing several aspects of the complex Notch signalling system in vitro, we found that both ligands have a similar trans-activation potential but that only DLL4 is an efficient cis-inhibitor of Notch signalling, causing a reduced net activation of Notch. These differential cis-inhibitory properties are likely to contribute to the functional divergence of DLL1 and DLL4.

  4. Context-Dependent Functional Divergence of the Notch Ligands DLL1 and DLL4 In Vivo.

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    Preuße, Kristina; Tveriakhina, Lena; Schuster-Gossler, Karin; Gaspar, Cláudia; Rosa, Alexandra Isabel; Henrique, Domingos; Gossler, Achim; Stauber, Michael

    2015-06-01

    Notch signalling is a fundamental pathway that shapes the developing embryo and sustains adult tissues by direct communication between ligand and receptor molecules on adjacent cells. Among the ligands are two Delta paralogues, DLL1 and DLL4, that are conserved in mammals and share a similar structure and sequence. They activate the Notch receptor partly in overlapping expression domains where they fulfil redundant functions in some processes (e.g. maintenance of the crypt cell progenitor pool). In other processes, however, they appear to act differently (e.g. maintenance of foetal arterial identity) raising the questions of how similar DLL1 and DLL4 really are and which mechanism causes the apparent context-dependent divergence. By analysing mice that conditionally overexpress DLL1 or DLL4 from the same genomic locus (Hprt) and mice that express DLL4 instead of DLL1 from the endogenous Dll1 locus (Dll1Dll4ki), we found functional differences that are tissue-specific: while DLL1 and DLL4 act redundantly during the maintenance of retinal progenitors, their function varies in the presomitic mesoderm (PSM) where somites form in a Notch-dependent process. In the anterior PSM, every cell expresses both Notch receptors and ligands, and DLL1 is the only activator of Notch while DLL4 is not endogenously expressed. Transgenic DLL4 cannot replace DLL1 during somitogenesis and in heterozygous Dll1Dll4ki/+ mice, the Dll1Dll4ki allele causes a dominant segmentation phenotype. Testing several aspects of the complex Notch signalling system in vitro, we found that both ligands have a similar trans-activation potential but that only DLL4 is an efficient cis-inhibitor of Notch signalling, causing a reduced net activation of Notch. These differential cis-inhibitory properties are likely to contribute to the functional divergence of DLL1 and DLL4.

  5. Relationships between bacterial community composition, functional trait composition and functioning are context dependent--but what is the context?

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    Ina Severin

    Full Text Available Bacterial communities are immensely diverse and drive many fundamental ecosystem processes. However, the role of bacterial community composition (BCC for functioning is still unclear. Here we evaluate the relative importance of BCC (from 454-sequencing, functional traits (from Biolog Ecoplates and environmental conditions for per cell biomass production (BPC; 3H-leucine incorporation in six data sets of natural freshwater bacterial communities. BCC explained significant variation of BPC in all six data sets and most variation in four. BCC measures based on 16S rRNA (active bacteria did not consistently explain more variation in BPC than measures based on the 16S rRNA-gene (total community, and adding phylogenetic information did not, in general, increase the explanatory power of BCC. In contrast to our hypothesis, the importance of BCC for BPC was not related to the anticipated dispersal rates in and out of communities. Functional traits, most notably the ability to use cyclic and aromatic compounds, as well as local environmental conditions, i.e. stoichiometric relationships of nutrients, explained some variation in all six data sets. In general there were weak associations between variation in BCC and variation in the functional traits contributing to productivity. This indicates that additional traits may be important for productivity as well. By comparing several data sets obtained in a similar way we conclude that no single measure of BCC was obviously better than another in explaining BPC. We identified some key functional traits for productivity, but although there was a coupling between BCC, functional traits and productivity, the strength of the coupling seems context dependent. However, the exact context is still unresolved.

  6. Context-dependent species identity effects within a functional group of filter-feeding bivalves.

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    Vaughn, Caryn C; Spooner, Daniel E; Galbraith, Heather S

    2007-07-01

    We asked whether species richness or species identity contributed more to ecosystem function in a trait-based functional group, burrowing, filter-feeding bivalves (freshwater mussels: Unionidae), and whether their importance changed with environmental context and species composition. We conducted a manipulative experiment in a small river examining the effects of mussel assemblages varying from one to eight species on benthic algal standing crop across two sets of environmental conditions: extremely low discharge and high water temperature (summer); and moderate discharge and water temperature (fall). We found strong species identity effects within this guild, with one species (Actinonaias ligamentina) influencing accrual of benthic algae more than other species, but only under summer conditions. We suspect that this effect is due to a combination of the greater biomass of this species and its higher metabolic and excretion rates at warm summer temperatures, resulting in increased nitrogen subsidies to benthic algae. We also found that Actinonaias influenced the condition of other mussel species, likely through higher consumption, interference, or both. This study demonstrates that species within trait-based functional groups do not necessarily have the same effects on ecosystem properties, particularly under different environmental conditions.

  7. Noncoding RNA Shows Context-Dependent Function | Center for Cancer Research

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    In addition to well-studied protein coding sequences, it is known that the genomes of higher organisms produce numerous noncoding RNAs (ncRNAs). Important roles for some ncRNAs in cell function have been demonstrated, though usually on a case-by-case basis, leading some scientists to argue that the majority of ncRNA production is just “noise” that results from the imperfect transcription machinery. The fact that many ncRNAs overlap with coding genes has hampered studies of their activities. Thus, a general understanding of whether ncRNA production is functional or not is lacking. To address this issue, Daniel Larson, Ph.D., of CCR’s Laboratory of Receptor Biology and Gene Expression, and his colleagues developed a new approach using single-molecule imaging in living cells. The researchers specifically labeled coding and ncRNAs from the GAL locus in yeast, which regulates the galactose response. Glucose is the preferred source of carbon for yeast, but when it is scarce, genes within the GAL locus, including GAL10 and GAL1, are activated to allow the metabolism of galactose.

  8. Reply: "Function of Cryopreserved Mesenchymal Stromal Cells With and Without Interferon-γ Prelicensing Is Context Dependent".

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    Galipeau, Jacques

    2017-05-01

    Freshly thawed mesenchymal stromal cells (MSCs) transiently display altered cell physiology and a recent report by Chinnadurai et al. [Stem Cells 2016;34:2429-2442] demonstrated that thawed allogeneic MSCs are also susceptible to T-cell mediated lysis in vitro and that this effect can be mitigated by activating MSCs with IFN-γ prior to freeze and thaw. In the letter to the editor by Ankrum et al., "Function of Cryopreserved MSCs with and without IFN-γ pre-licensing is Context Dependent," the author provide data that IFN-γ pretreatment of human MSCs before cryobanking fails to enhance their potency post thaw in a mouse model of retinal disease. Considering that the experimental set up involves the use of human MSCs in mice with normal immune systems, we propose that IFN-γ MSC activation enhances the immune incompatibility of xenogenic human cells in a manner which may confound the predictive value for human translational use. Stem Cells 2017;35:1440-1441. © 2016 AlphaMed Press.

  9. Functional subdivisions within the human intraparietal sulcus are involved in visuospatial transformation in a non-context-dependent manner.

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    Papadopoulos, Alexandra; Sforazzini, Francesco; Egan, Gary; Jamadar, Sharna

    2018-01-01

    Object-based visuospatial transformation is important for the ability to interact with the world and the people and objects within it. In this preliminary investigation, we hypothesized that object-based visuospatial transformation is a unitary process invoked regardless of current context and is localized to the intraparietal sulcus. Participants (n = 14) performed both antisaccade and mental rotation tasks while scanned using fMRI. A statistical conjunction confirmed that both tasks activated the intraparietal sulcus. Statistical parametric anatomical mapping determined that the statistical conjunction was localized to intraparietal sulcus subregions hIP2 and hIP3. A Gaussian naïve Bayes classifier confirmed that the conjunction in region hIP3 was indistinguishable between tasks. The results provide evidence that object-based visuospatial transformation is a domain-general process that is invoked regardless of current context. Our results are consistent with the modular model of the posterior parietal cortex and the distinct cytoarchitectonic, structural, and functional connectivity profiles of the subregions in the intraparietal sulcus. Hum Brain Mapp 39:354-368, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  10. Stress Disrupts Context-Dependent Memory

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    Schwabe, Lars; Bohringer, Andreas; Wolf, Oliver T.

    2009-01-01

    Memory is facilitated when the retrieval context resembles the learning context. The brain structures underlying contextual influences on memory are susceptible to stress. Whether stress interferes with context-dependent memory is still unknown. We exposed healthy adults to stress or a control procedure before they learned an object-location task…

  11. Specification and Verification of Context-dependent Services

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    Naseem Ibrahim

    2011-08-01

    Full Text Available Current approaches for the discovery, specification, and provision of services ignore the relationship between the service contract and the conditions in which the service can guarantee its contract. Moreover, they do not use formal methods for specifying services, contracts, and compositions. Without a formal basis it is not possible to justify through formal verification the correctness conditions for service compositions and the satisfaction of contractual obligations in service provisions. We remedy this situation in this paper. We present a formal definition of services with context-dependent contracts. We define a composition theory of services with context-dependent contracts taking into consideration functional, nonfunctional, legal and contextual information. Finally, we present a formal verification approach that transforms the formal specification of service composition into extended timed automata that can be verified using the model checking tool UPPAAL.

  12. A Context-dependent Service Model

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    Naseem Ibrahim

    2014-12-01

    Full Text Available In service-oriented systems a service invariably is bound to a contract. This contract includes the functionalities and quality of services guarantees that the provider can make. But such guarantees are not absolute. A service cannot guarantee its contract in all situations. It can only guarantee its contract in a predefined set of conditions. These conditions are usually related to the context of the service provider and requester. Yet, most of service-oriented applications use only service functionality as the basis of providing services and building system compositions. To remedy this situation, in this article both functionality and contract of a service are integrated into a single concept, called ConfiguredService, and formalized as a higher-order data type. The service part that includes the functionality, nonfunctional properties, service parameters, and data of the service requester, is loosely coupled to the contract part that includes trustworthiness claims, legal and business rules governing the service provision, and the context information pertaining to the provider and receiver. This loose coupling allows the creation of many ConfiguredServices, which share the same functionality but possess different contract parts. To facilitate dynamic service adaptation, we introduce a syntax and semantics for extending or modifying a ConfiguredService.

  13. Context-dependent logo matching and recognition.

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    Sahbi, Hichem; Ballan, Lamberto; Serra, Giuseppe; Del Bimbo, Alberto

    2013-03-01

    We contribute, through this paper, to the design of a novel variational framework able to match and recognize multiple instances of multiple reference logos in image archives. Reference logos and test images are seen as constellations of local features (interest points, regions, etc.) and matched by minimizing an energy function mixing: 1) a fidelity term that measures the quality of feature matching, 2) a neighborhood criterion that captures feature co-occurrence/geometry, and 3) a regularization term that controls the smoothness of the matching solution. We also introduce a detection/recognition procedure and study its theoretical consistency. Finally, we show the validity of our method through extensive experiments on the challenging MICC-Logos dataset. Our method overtakes, by 20%, baseline as well as state-of-the-art matching/recognition procedures.

  14. Peptide-Based Selective Inhibitors of Matrix Metalloproteinase-Mediated Activities

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    Margaret W. Ndinguri

    2012-11-01

    Full Text Available The matrix metalloproteinases (MMPs exhibit a broad array of activities, some catalytic and some non-catalytic in nature. An overall lack of selectivity has rendered small molecule, active site targeted MMP inhibitors problematic in execution. Inhibitors that favor few or individual members of the MMP family often take advantage of interactions outside the enzyme active site. We presently focus on peptide-based MMP inhibitors and probes that do not incorporate conventional Zn2+ binding groups. In some cases, these inhibitors and probes function by binding only secondary binding sites (exosites, while others bind both exosites and the active site. A myriad of MMP mediated-activities beyond selective catalysis can be inhibited by peptides, particularly cell adhesion, proliferation, motility, and invasion. Selective MMP binding peptides comprise highly customizable, unique imaging agents. Areas of needed improvement for MMP targeting peptides include binding affinity and stability.

  15. Emotion recognition specialization and context-dependent risk of anxiety and depression in adolescents

    NARCIS (Netherlands)

    Oldehinkel, Albertine J.; Hartman, Catharina A.; Van Oort, Floor V. A.; Nederhof, Esther

    Background Some adolescents function poorly in apparently benign environments, while others thrive despite hassles and difficulties. The aim of this study was to examine if adolescents with specialized skills in the recognition of either positive or negative emotions have a context-dependent risk of

  16. Context dependent prediction and category encoding for DPCM image compression

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    Beaudet, Paul R.

    1989-01-01

    Efficient compression of image data requires the understanding of the noise characteristics of sensors as well as the redundancy expected in imagery. Herein, the techniques of Differential Pulse Code Modulation (DPCM) are reviewed and modified for information-preserving data compression. The modifications include: mapping from intensity to an equal variance space; context dependent one and two dimensional predictors; rationale for nonlinear DPCM encoding based upon an image quality model; context dependent variable length encoding of 2x2 data blocks; and feedback control for constant output rate systems. Examples are presented at compression rates between 1.3 and 2.8 bits per pixel. The need for larger block sizes, 2D context dependent predictors, and the hope for sub-bits-per-pixel compression which maintains spacial resolution (information preserving) are discussed.

  17. Feature context-dependency and complexity-reduction in probability landscapes for integrative genomics

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    Benecke Arndt

    2008-09-01

    Full Text Available Abstract Background The question of how to integrate heterogeneous sources of biological information into a coherent framework that allows the gene regulatory code in eukaryotes to be systematically investigated is one of the major challenges faced by systems biology. Probability landscapes, which include as reference set the probabilistic representation of the genomic sequence, have been proposed as a possible approach to the systematic discovery and analysis of correlations amongst initially heterogeneous and un-relatable descriptions and genome-wide measurements. Much of the available experimental sequence and genome activity information is de facto, but not necessarily obviously, context dependent. Furthermore, the context dependency of the relevant information is itself dependent on the biological question addressed. It is hence necessary to develop a systematic way of discovering the context-dependency of functional genomics information in a flexible, question-dependent manner. Results We demonstrate here how feature context-dependency can be systematically investigated using probability landscapes. Furthermore, we show how different feature probability profiles can be conditionally collapsed to reduce the computational and formal, mathematical complexity of probability landscapes. Interestingly, the possibility of complexity reduction can be linked directly to the analysis of context-dependency. Conclusion These two advances in our understanding of the properties of probability landscapes not only simplify subsequent cross-correlation analysis in hypothesis-driven model building and testing, but also provide additional insights into the biological gene regulatory problems studied. Furthermore, insights into the nature of individual features and a classification of features according to their minimal context-dependency are achieved. The formal structure proposed contributes to a concrete and tangible basis for attempting to formulate novel

  18. Context-Dependent Competition in a Model Gut Bacterial Community

    OpenAIRE

    de Muinck, Eric J.; Stenseth, Nils Chr.; Sachse, Daniel; vander Roost, Jan; R?nningen, Kjersti S.; Rudi, Knut; Trosvik, P?l

    2013-01-01

    Understanding the ecological processes that generate complex community structures may provide insight into the establishment and maintenance of a normal microbial community in the human gastrointestinal tract, yet very little is known about how biotic interactions influence community dynamics in this system. Here, we use natural strains of Escherichia coli and a simplified model microbiota to demonstrate that the colonization process on the strain level can be context dependent, in the sense ...

  19. Curation of complex, context-dependent immunological data

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    Sidney John

    2006-07-01

    Full Text Available Abstract Background The Immune Epitope Database and Analysis Resource (IEDB is dedicated to capturing, housing and analyzing complex immune epitope related data http://www.immuneepitope.org. Description To identify and extract relevant data from the scientific literature in an efficient and accurate manner, novel processes were developed for manual and semi-automated annotation. Conclusion Formalized curation strategies enable the processing of a large volume of context-dependent data, which are now available to the scientific community in an accessible and transparent format. The experiences described herein are applicable to other databases housing complex biological data and requiring a high level of curation expertise.

  20. Context-dependent discrimination and the evolution of mimicry.

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    Holen, Øistein Haugsten; Johnstone, Rufus A

    2006-03-01

    Many mimetic organisms have evolved a close resemblance to their models, making it difficult to discriminate between them on the basis of appearance alone. However, if mimics and models differ slightly in their activity patterns, behavior, or use of microhabitats, the exact circumstances under which a signaler is encountered may provide additional clues to its identity. We employ an optimality model of mimetic discrimination in which signal receivers obtain information about the relative risk of encountering mimics and models by observing an external background cue and flexibly adjust their response thresholds. Although such flexibility on the part of signal receivers has been predicted by theory and is supported by empirical evidence in a range of biological settings, little is known about the effects it has on signalers. We show that the presence of external cues that partly reveal signaler identity may benefit models and harm mimics, harm both, or even benefit both, depending on ecological circumstances. Moreover, if mimetic traits are costly to express, or mimics are related to their neighbors, context-dependent discrimination can dramatically alter the outcome of mimetic evolution. We discuss context-dependent discrimination among signal receivers in relation to small-scale synchrony in model and mimic activity patterns.

  1. Brain structural connectivity and context-dependent extinction memory.

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    Hermann, Andrea; Stark, Rudolf; Blecker, Carlo R; Milad, Mohammed R; Merz, Christian J

    2017-08-01

    Extinction of conditioned fear represents an important mechanism in the treatment of anxiety disorders. Return of fear after successful extinction or exposure therapy in patients with anxiety disorders might be linked to poor temporal or contextual generalization of extinction due to individual differences in brain structural connectivity. The goal of this magnetic resonance imaging study was therefore to investigate the association of context-dependent extinction recall with brain structural connectivity. Diffusion-tensor imaging was used to determine the fractional anisotropy as a measure of white matter structural integrity of fiber tracts connecting central brain regions of the fear and extinction circuit (uncinate fasciculus, cingulum). Forty-five healthy men participated in a two-day fear conditioning experiment with fear acquisition in context A and extinction learning in context B on the first day. Extinction recall in the extinction context as well as renewal in the acquisition context and a novel context C took place one day later. Renewal of conditioned fear (skin conductance responses) in the acquisition context was associated with higher structural integrity of the hippocampal part of the cingulum. Enhanced structural integrity of the cingulum might be related to stronger hippocampal modulation of the dorsal anterior cingulate cortex, a region important for modulating conditioned fear output by excitatory projections to the amygdala. This finding underpins the crucial role of individual differences in the structural integrity of relevant fiber tracts for context-dependent extinction recall and return of fear after exposure therapy in anxiety disorders. © 2017 Wiley Periodicals, Inc.

  2. Context-dependent Reasoning for the Semantic Web

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    Neli P. Zlatareva

    2011-08-01

    Full Text Available Ontologies are the backbone of the emerging Semantic Web, which is envisioned to dramatically improve current web services by extending them with intelligent capabilities such as reasoning and context-awareness. They define a shared vocabulary of common domains accessible to both, humans and computers, and support various types of information management including storage and processing of data. Current ontology languages, which are designed to be decidable to allow for automatic data processing, target simple typed ontologies that are completely and consistently specified. As the size of ontologies and the complexity of web applications grow, the need for more flexible representation and reasoning schemes emerges. This article presents a logical framework utilizing context-dependent rules which are intended to support not fully and/or precisely specified ontologies. A hypothetical application scenario is described to illustrate the type of ontologies targeted, and the type of queries that the presented logical framework is intended to address.

  3. Hybrid methodological approach to context-dependent speech recognition

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    Dragiša Mišković

    2017-01-01

    Full Text Available Although the importance of contextual information in speech recognition has been acknowledged for a long time now, it has remained clearly underutilized even in state-of-the-art speech recognition systems. This article introduces a novel, methodologically hybrid approach to the research question of context-dependent speech recognition in human–machine interaction. To the extent that it is hybrid, the approach integrates aspects of both statistical and representational paradigms. We extend the standard statistical pattern-matching approach with a cognitively inspired and analytically tractable model with explanatory power. This methodological extension allows for accounting for contextual information which is otherwise unavailable in speech recognition systems, and using it to improve post-processing of recognition hypotheses. The article introduces an algorithm for evaluation of recognition hypotheses, illustrates it for concrete interaction domains, and discusses its implementation within two prototype conversational agents.

  4. Context dependency and generality of fever in insects

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    Stahlschmidt, Z. R.; Adamo, S. A.

    2013-07-01

    Fever can reduce mortality in infected animals. Yet, despite its fitness-enhancing qualities, fever often varies among animals. We used several approaches to examine this variation in insects. Texas field crickets ( Gryllus texensis) exhibited a modest fever (1 °C increase in preferred body temperature, T pref) after injection of prostaglandin, which putatively mediates fever in both vertebrates and invertebrates, but they did not exhibit fever during chronic exposure to heat-killed bacteria. Further, chronic food limitation and mating status did not affect T pref or the expression of behavioural fever, suggesting limited context dependency of fever in G. texensis. Our meta-analysis of behavioural fever studies indicated that behavioural fever occurs in many insects, but it is not ubiquitous. Thus, both empirical and meta-analytical results suggest that the fever response in insects `is widespread, although certainly not inevitable' (Moore 2002). We highlight the need for future work focusing on standardizing an experimental protocol to measure behavioural fever, understanding the specific mechanism(s) underlying fever in insects, and examining whether ecological or physiological costs often outweigh the benefits of fever and can explain the sporadic nature of fever in insects.

  5. Emotion recognition specialization and context-dependent risk of anxiety and depression in adolescents

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    Oldehinkel, Albertine J; Hartman, Catharina A; Van Oort, Floor V A; Nederhof, Esther

    2015-01-01

    Background Some adolescents function poorly in apparently benign environments, while others thrive despite hassles and difficulties. The aim of this study was to examine if adolescents with specialized skills in the recognition of either positive or negative emotions have a context-dependent risk of developing an anxiety or depressive disorder during adolescence, depending on exposure to positive or harsh parenting. Methods Data came from a large prospective Dutch population study (N = 1539). At age 11, perceived parental rejection and emotional warmth were measured by questionnaire, and emotion recognition skills by means of a reaction-time task. Lifetime diagnoses of anxiety and depressive disorders were assessed at about age 19, using a standardized diagnostic interview. Results Adolescents who were specialized in the recognition of positive emotions had a relatively high probability to develop an anxiety disorder when exposed to parental rejection (Bspecialization*rejection = 0.23, P anxiety or depressive disorder in adolescence, and that emotion recognition specialization may be a promising way to distinguish between various types of context-dependent reaction patterns. PMID:25642389

  6. Investigating the context-dependency of plant-soil-AMF-microbe interactions along a pollution gradient

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    Glassman, S. I.; Casper, B. B.

    2010-12-01

    Background/Question/Methods Investigating how arbuscular mycorrhizal fungi (AMF)-plant interactions vary with edaphic conditions provides an opportunity to test the context-dependency of interspecific interactions, which is currently recognized as a major avenue of future research. We study plant-mycorrhiza symbiotic relationships along a gradient of heavy metal contamination at a recently revegetated “Superfund” site on Blue Mountain, in Palmerton, Pennsylvania. We investigated the interactions involving the native mycorrhizal fungi, non-mycorrhizal soil microbes, soil, and two plant species (a C3 and C4 grass) along the contamination gradient. The native C3 study species Deschampsia flexuosa, is dominant along the gradient and established naturally; the C4 Sorghastrum nutans, is native to Pennsylvania but not to the site and was introduced during restoration. Because C4 grasses are obligate mycotrophs, we expected S. nutans to have a different effect on and response to the soil symbiont community than the C3 grass. We carried out a full factorial greenhouse experiment using field-collected seeds of D. flexuosa and S. nutans, soil, AMF spores, and non-mycorrhizal microbes from both high and low contaminated ends of the gradient. After 11 weeks of growth in the greenhouses, we harvested above and belowground plant biomass, and quantified AMF root colonization and AMF sporulation. Results/Conclusions Our results indicate that context-dependent function is an important factor driving specific ecological interactions between plants and soil microbes. We found that soil origin significantly affected plant growth. Plants from both species grew much larger in soil from low contaminated (LC) origin than high contaminated (HC) origin. Furthermore, we found that the efficacy of AMF in promoting plant growth depended on AMF origin. Specifically, AMF from LC improved growth of D. flexuosa best in either soil background and improved survivorship of S. nutans in HC soil

  7. Context-Dependent Neural Modulations in the Perception of Duration.

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    Murai, Yuki; Yotsumoto, Yuko

    2016-01-01

    Recent neuroimaging studies have revealed that distinct brain networks are recruited in the perception of sub- and supra-second timescales, whereas psychophysical studies have suggested that there are common or continuous mechanisms for perceiving these two durations. The present study aimed to elucidate the neural implementation of such continuity by examining the neural correlates of peri-second timing. We measured neural activity during a duration reproduction task using functional magnetic resonance imaging. Our results replicate the findings of previous studies in showing that separate neural networks are recruited for sub-versus supra-second time perception: motor systems including the motor cortex and the supplementary motor area for sub-second perception, and the frontal, parietal, and auditory cortical areas for supra-second perception. We further found that the peri-second perception activated both the sub- and supra-second networks, and that the timing system that processed duration perception in previous trials was more involved in subsequent peri-second processing. These results indicate that the sub- and supra-second timing systems overlap at around 1 s, and cooperate to optimally encode duration based on the hysteresis of previous trials.

  8. Context-dependent reproductive habitat selection: the interactive roles of structural complexity and cannibalistic conspecifics.

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    Sadeh, Asaf; Mangel, Marc; Blaustein, Leon

    2009-11-01

    Structural complexity generally reduces predation and cannibalism rates. Although the benefits from this effect vary among environmental contexts and through time, it has been the common explanation for high species abundance in complex habitats. We hypothesized that oviposition habitat selection for structural complexity depends on the expected trophic function of the progeny. In Salamandra infraimmaculata larvae, expected trophic function is dictated by their sequence of deposition. First cohorts cannibalize later-arriving cohorts, while all compete for shared prey resources. In a mesocosm experiment, we show that gravid salamanders facing conspecific-free pools preferred structurally simple habitats (no rocks), while females facing only pools with older conspecific larvae preferred complex habitats (with rocks). Context-dependent preference of habitat complexity for managing food/safety trade-offs may be extended from classic foraging patch decisions to breeding habitat selection. These trade-offs vary with dynamic larval processes such as priority effects and ontogenetic diet shifts, potentially leading to complex maternal parturition behaviours.

  9. Context-dependence of Aimed Arm Movements: A Transitory or A Stable Phenomenon?

    Directory of Open Access Journals (Sweden)

    Benjamin Baak

    2014-10-01

    Full Text Available Previous work documented that grasping movements in a typical laboratory context differ widely from those in a more natural context. We evaluate whether this context-dependence changes with experience. Data from 48 subjects (24 female; 24.9 ± 2.7 years of age were (reanalyzed. They had participated in experimental blocks with externally triggered, purposeless and repetitive movements (context L, laboratory-like, and a block with self-initiated, ecologically valid movements embedded in a complex task (context E, everyday-like. Mechanical constraints on grasping were identical in both blocks. A global metric, representing context-dependence across multiple kinematic parameters, did not change appreciably across the 20 trials of a block. Furthermore, the metric was not affected by prior participation in the other block. We conclude that context-dependence of grasping is robust, i.e., it shows little influence of prior experience. This opens the avenue for within-subject designs on context-dependence, e.g., for clinical investigations. Keywords: Motor control, Prehension, Context-dependence, Serial order, Attunement

  10. Context-dependent motor skill: perceptual processing in memory-based sequence production

    NARCIS (Netherlands)

    Ruitenberg, M.F.L.; Abrahamse, E.L.; de Kleine, Elian; Verwey, Willem B.

    2012-01-01

    Previous studies have shown that motor sequencing skill can benefit from the reinstatement of the learning context—even with respect to features that are formally not required for appropriate task performance. The present study explored whether such context-dependence develops when sequence

  11. Context-dependent effects of background colour in free recall with spatially grouped words.

    Science.gov (United States)

    Sakai, Tetsuya; Isarida, Toshiko K; Isarida, Takeo

    2010-10-01

    Three experiments investigated context-dependent effects of background colour in free recall with groups of items. Undergraduates (N=113) intentionally studied 24 words presented in blocks of 6 on a computer screen with two different background colours. The two background colours were changed screen-by-screen randomly (random condition) or alternately (alternation condition) during the study period. A 30-second filled retention interval was imposed before an oral free-recall test. A signal for free recall was presented throughout the test on one of the colour background screens presented at study. Recalled words were classified as same- or different-context words according to whether the background colours at study and test were the same or different. The random condition produced significant context-dependent effects, whereas the alternation condition showed no context-dependent effects, regardless of whether the words were presented once or twice. Furthermore, the words presented on the same screen were clustered in recall, whereas the words presented against the same background colour but on different screens were not clustered. The present results imply: (1) background colours can cue spatially massed words; (2) background colours act as temporally local context; and (3) predictability of the next background colour modulates the context-dependent effect.

  12. Context-dependent modelling of English vowels in Sepedi code-switched speech

    CSIR Research Space (South Africa)

    Modipa, TI

    2012-11-01

    Full Text Available phone to a matrix language counterpart. We use acoustic log likelihoods to assist us in identifying the optimal mapping strategy at a context-dependent level (that is, at triphone, rather than monophone level) and obtain new insights in the way English...

  13. Context-dependent memory in two natural environments: on land and underwater

    Science.gov (United States)

    Godden, D. R.; Baddeley, A. D.

    1975-01-01

    In a free recall experiment, divers learn lists of words in two natural environments: on dry land and underwater, and recalled the words in either the environment of original learning, or in the alternative environment. A subsequent experiment related these actions to context-dependent memory. (Editor/RK)

  14. Context-Dependent Help for the DynaLearn Modelling and Simulation Workbench

    NARCIS (Netherlands)

    Beek, W.; Bredeweg, B.; Latour, S.; Biswas, G.; Bull, S.; Kay, J.; Mitrovic, A.

    2011-01-01

    We implemented three kinds of context-dependent help for a qualitative modelling and simulation workbench called DynaLearn. We show that it is possible to generate and select assistance knowledge based on the current model, simulation results and workbench state.

  15. Context-Dependent Prognostics and Health Assessment: A Condition-Based Maintenance Approach That Supports Mission Compliance

    Energy Technology Data Exchange (ETDEWEB)

    Allgood, G.O.; Kercel, S.W.

    1999-04-19

    In today's manufacturing environment, plants, systems, and equipment are being asked to perform at levels not thought possible a decade ago. The intent is to improve process operations and equipment reliability, availability, and maintainability without costly upgrades. Of course these gains must be achieved without impacting operational performance. Downsizing is also taking its toll on operations. Loss of personnel, particularly those who represent the corporate history, is depleting US industries of their valuable experiential base which has been relied on so heavily in the past. These realizations are causing companies to rethink their condition-based maintenance policies by moving away from reacting to equipment problems to taking a proactive approach by anticipating needs based on market and customer requirements. This paper describes a different approach to condition-based maintenance-context-dependent prognostics and health assessment. This diagnostic capability is developed around a context-dependent model that provides a capability to anticipate impending failures and determine machine performance over a protracted period of time. This prognostic capability links operational requirements to an economic performance model. In this context, a system may provide 100% operability with less than 100% functionality. This paradigm is used to facilitate optimal logistic supply and support.

  16. Context-dependent risks and benefits of transfusion in the critically ill

    Directory of Open Access Journals (Sweden)

    Harahsheh Y

    2017-03-01

    Full Text Available Yusrah Harahsheh,1,2 Kwok M Ho1,3,4 1Department of Intensive Care Medicine, Royal Perth Hospital, 2School of Medicine & Pharmacology, 3School of Population Health, University of Western Australia, 4School of Veterinary & Life Sciences, Murdoch University, Perth, WA, Australia Abstract: Transfusion of red blood cells (RBCs and other blood products to critically ill patients is common. Blood products are expensive, and not without risks. Recent evidence from high-quality multicenter randomized controlled trials confirmed the safety of allogeneic RBC transfusions, including the use of aged RBCs, and mild to moderate anemia for most stable and nonbleeding critically ill patients. Emerging evidence suggests that a liberal RBC transfusion target may have potential divergent effects on patient outcomes depending on their clinical context, with possible harms for patients with gastrointestinal bleeding due to portal hypertension and, conversely, benefits for patients with severe underlying cardiovascular diseases. Despite an apparent increased risk of bleeding in critically ill patients with deranged coagulation parameters and thrombocytopenia, recent studies suggested that fresh frozen plasma (FFP and platelet transfusions may not be beneficial and, indeed, also not very effective in correcting these abnormalities. As for patients who have active severe critical bleeding, use of empirical 1:1:1 RBC: platelets: FFP transfusion appears justifiable in an attempt to reduce deaths as a result of exsanguination. In conjunction with platelet count and fibrinogen concentration, whole blood viscoelastic and platelet function tests are particularly useful to assist clinicians to rationalize FFP and platelet transfusions, when imminent death from exsanguination is not anticipated. Because the risks and benefits of blood product transfusion are heavily context-dependent, a thorough consideration of the characteristics and clinical status of the patients, in

  17. Binding and Normalization of Binary Sparse Distributed Representations by Context-Dependent Thinning

    OpenAIRE

    Rachkovskij, Dmitri A.; Kussul, Ernst M.

    2001-01-01

    Distributed representations were often criticized as inappropriate for encoding of data with a complex structure. However Plate's Holographic Reduced Representations and Kanerva's Binary Spatter Codes are recent schemes that allow on-the-fly encoding of nested compositional structures by real-valued or dense binary vectors of fixed dimensionality. In this paper we consider procedures of the Context-Dependent Thinning which were developed for representation of complex hierarchical items in the...

  18. Context-dependent medicinal effects of anabasine and infection-dependent toxicity in bumble bees.

    Science.gov (United States)

    Palmer-Young, Evan C; Hogeboom, Alison; Kaye, Alexander J; Donnelly, Dash; Andicoechea, Jonathan; Connon, Sara June; Weston, Ian; Skyrm, Kimberly; Irwin, Rebecca E; Adler, Lynn S

    2017-01-01

    tritrophic interactions by both host genotype and environmental variables. Overall, our results demonstrate that Bombus impatiens prefer diets without nicotine and anabasine, and suggest that the medicinal effects and toxicity of anabasine may be context dependent. Future research should identify the specific environmental and genotypic factors that determine whether nectar phytochemicals have medicinal or deleterious effects on pollinators.

  19. Context-dependent medicinal effects of anabasine and infection-dependent toxicity in bumble bees.

    Directory of Open Access Journals (Sweden)

    Evan C Palmer-Young

    modulation of tritrophic interactions by both host genotype and environmental variables. Overall, our results demonstrate that Bombus impatiens prefer diets without nicotine and anabasine, and suggest that the medicinal effects and toxicity of anabasine may be context dependent. Future research should identify the specific environmental and genotypic factors that determine whether nectar phytochemicals have medicinal or deleterious effects on pollinators.

  20. Context-dependent Changes in Functional Connectivity of Auditory Cortices during the Perception of Object Words

    NARCIS (Netherlands)

    Dam, W.O. van; Dongen, E.V. van; Bekkering, H.; Rüschemeyer, S.A.

    2012-01-01

    Embodied theories hold that cognitive concepts are grounded in our sensorimotor systems. Specifically, a number of behavioral and neuroimaging studies have buttressed the idea that language concepts are represented in areas involved in perception and action [Pulvermueller, F. Brain mechanisms

  1. Context-dependent changes in functional connectivity of auditory cortices during the perception of object words

    NARCIS (Netherlands)

    van Dam, W.O.; Dongen, E.V. van; Bekkering, H.; Rueschemeyer, S.A.

    2012-01-01

    Embodied theories hold that cognitive concepts are grounded in our sensorimotor systems. Specifically, a number of behavioral and neuroimaging studies have buttressed the idea that language concepts are represented in areas involved in perception and action [Pulvermueller, F. Brain mechanisms

  2. Ensemble coding of context-dependent fear memory in the amygdala

    Directory of Open Access Journals (Sweden)

    Caitlin A Orsini

    2013-12-01

    Full Text Available After fear conditioning, presenting the conditioned stimulus (CS alone yields a context-specific extinction memory; fear is suppressed in the extinction context, but renews in any other context. The context-dependence of extinction is mediated by a brain circuit consisting of the hippocampus, prefrontal cortex and amygdala. In the present work, we sought to determine at what level of this circuit context-dependent representations of the CS emerge. To explore this question, we used cellular compartment analysis of temporal activity by fluorescent in situ hybridization (catFISH. This method exploits the intracellular expression profile of the immediate early gene, Arc, to visualize neuronal activation patterns to two different behavioral experiences. Rats were fear conditioned in one context and extinguished in another; twenty-four hours later, they were sequentially exposed to the CS in the extinction context and another context. Control rats were also tested in each context, but were never extinguished. We assessed Arc mRNA expression within the basal amygdala (BA, lateral amygdala (LA, ventral hippocampus (VH, prelimbic cortex (PL and infralimbic cortex (IL. We observed that the sequential retention tests induced context-dependent patterns of Arc expression in the BA, LA, and IL of extinguished rats; this was not observed in non-extinguished controls. In general, non-extinguished animals had proportionately greater numbers of non-selective (double-labeled neurons than extinguished animals. Collectively, these findings suggest that extinction learning results in pattern separation, particularly within the BA, in which unique neuronal ensembles represent fear memories after extinction.

  3. Processing Incomplete Query Specifications in a Context-Dependent Reasoning Framework

    Directory of Open Access Journals (Sweden)

    Neli P. Zlatareva

    2013-04-01

    Full Text Available Search is the most prominent web service, which is about to change dramatically with the transition to the Semantic Web. Semantic Web applications are expected to deal with complex conjunctive queries, and not always such queries can be completely and precisely defined. Current Semantic Web reasoners built upon Description Logics have limited processing power in such environments. We discuss some of their limitations, and show how an alternative logical framework utilizing context-dependent rules can be extended to handle incomplete or imprecise query specifications.

  4. Neighbor Preferences of Amino Acids and Context-Dependent Effects of Amino Acid Substitutions in Human, Mouse, and Dog

    Directory of Open Access Journals (Sweden)

    Mingchuan Fu

    2014-09-01

    Full Text Available Amino acids show apparent propensities toward their neighbors. In addition to preferences of amino acids for their neighborhood context, amino acid substitutions are also considered to be context-dependent. However, context-dependence patterns of amino acid substitutions still remain poorly understood. Using relative entropy, we investigated the neighbor preferences of 20 amino acids and the context-dependent effects of amino acid substitutions with protein sequences in human, mouse, and dog. For 20 amino acids, the highest relative entropy was mostly observed at the nearest adjacent site of either N- or C-terminus except C and G. C showed the highest relative entropy at the third flanking site and periodic pattern was detected at G flanking sites. Furthermore, neighbor preference patterns of amino acids varied greatly in different secondary structures. We then comprehensively investigated the context-dependent effects of amino acid substitutions. Our results showed that nearly half of 380 substitution types were evidently context dependent, and the context-dependent patterns relied on protein secondary structures. Among 20 amino acids, P elicited the greatest effect on amino acid substitutions. The underlying mechanisms of context-dependent effects of amino acid substitutions were possibly mutation bias at a DNA level and natural selection. Our findings may improve secondary structure prediction algorithms and protein design; moreover, this study provided useful information to develop empirical models of protein evolution that consider dependence between residues.

  5. Context Dependent Effect of Landscape on the Occurrence of an Apex Predator across Different Climate Regions.

    Science.gov (United States)

    Fujita, Go; Azuma, Atsuki; Nonaka, Jun; Sakai, Yoshiaki; Sakai, Hatsumi; Iseki, Fumitaka; Itaya, Hiroo; Fukasawa, Keita; Miyashita, Tadashi

    2016-01-01

    In studies of habitat suitability at landscape scales, transferability of species-landscape associations among sites are likely to be critical because it is often impractical to collect datasets across various regions. However, limiting factors, such as prey availability, are not likely to be constant across scales because of the differences in species pools. This is particularly true for top predators that are often the target for conservation concern. Here we focus on gray-faced buzzards, apex predators of farmland-dominated landscapes in East Asia. We investigated context dependency of "buzzard-landscape relationship", using nest location datasets from five sites, each differing in landscape composition. Based on the similarities of prey items and landscape compositions across the sites, we determined several alternative ways of grouping the sites, and then examined whether buzzard-landscape relationship change among groups, which was conducted separately for each way of grouping. As a result, the model of study-sites grouping based on similarities in prey items showed the smallest ΔAICc. Because the terms of interaction between group IDs and areas of broad-leaved forests and grasslands were selected, buzzard-landscape relationship showed a context dependency, i.e., these two landscape elements strengthen the relationship in southern region. The difference in prey fauna, which is associated with the difference in climate, might generate regional differences in the buzzard-landscape associations.

  6. Context dependency and consumer acceptance of risk reducing strategies - a choice experiment study on salmonella risks in pork

    DEFF Research Database (Denmark)

    Mørkbak, Morten Raun; Christensen, Tove; Gyrd-Hansen, Dorte

    2012-01-01

    The paper investigates to what extent context dependency is present, when consumers are introduced to different risk reducing technologies and how this will affect their preferences for reductions in food risks. In particular, choice experiments are used to elicit consumer preferences for reducin...... findings of bad news having greater effect than good news – now applied to context dependency of preferences for food safety technologies.......The paper investigates to what extent context dependency is present, when consumers are introduced to different risk reducing technologies and how this will affect their preferences for reductions in food risks. In particular, choice experiments are used to elicit consumer preferences for reducing...... Salmonella risks in pork using farm level interventions vs. decontamination of meat at the abattoir. We found an interesting asymmetry in the context dependency. The presence of the least preferred risk reduction technology (lactic acid decontamination) affected the relative preferences for the two most...

  7. Context dependent off loading for cloudlet in mobile ad-hoc network

    Science.gov (United States)

    Bhatt, N.; Nadesh, R. K.; ArivuSelvan, K.

    2017-11-01

    Cloud Computing in Mobile Ad-hoc network is emerging part of research consideration as the demand and competency of mobile devices increased in last few years. To follow out operation within the remote cloud builds the postponement and influences the administration standard. To keep away from this trouble cloudlet is presented. Cloudlet gives identical support of the devices as cloud at low inactivity however at high transfer speed. Be that as it may, choice of a cloudlet for offloading calculation with flat energy is a noteworthy test if multiple cloud let is accessible adjacent. Here I proposed energy and bandwidth (Traffic overload for communication with cloud) aware cloudlet selection strategy based on the context dependency of the device location. It works on the basis of mobile device location and bandwidth availability of cloudlet. The cloudlet offloading and selection process using given solution is simulated in Cloud ~ Simulator.

  8. Variable length and context-dependent HMM letter form models for Arabic handwritten word recognition

    Science.gov (United States)

    Bianne-Bernard, Anne-Laure; Menasri, Fares; Likforman-Sulem, Laurence; Mokbel, Chafic; Kermorvant, Christopher

    2012-01-01

    We present in this paper an HMM-based recognizer for the recognition of unconstrained Arabic handwritten words. The recognizer is a context-dependent HMM which considers variable topology and contextual information for a better modeling of writing units. We propose an algorithm to adapt the topology of each HMM to the character to be modeled. For modeling the contextual units, a state-tying process based on decision tree clustering is introduced which significantly reduces the number of parameters. Decision trees are built according to a set of expert-based questions on how characters are written. Questions are divided into global questions yielding larger clusters and precise questions yielding smaller ones. We apply this modeling to the recognition of Arabic handwritten words. Experiments conducted on the OpenHaRT2010 database show that variable length topology and contextual information significantly improves the recognition rate.

  9. Long-lasting context dependence constrains neural encoding models in rodent auditory cortex.

    Science.gov (United States)

    Asari, Hiroki; Zador, Anthony M

    2009-11-01

    Acoustic processing requires integration over time. We have used in vivo intracellular recording to measure neuronal integration times in anesthetized rats. Using natural sounds and other stimuli, we found that synaptic inputs to auditory cortical neurons showed a rather long context dependence, up to > or =4 s (tau approximately 1 s), even though sound-evoked excitatory and inhibitory conductances per se rarely lasted greater, similar 100 ms. Thalamic neurons showed only a much faster form of adaptation with a decay constant tau history to only a few hundred milliseconds reduced the predictable response component to about half that of the optimal infinite-history model. Our results demonstrate the importance of long-range temporal effects in auditory cortex and suggest a potential neural substrate for auditory processing that requires integration over timescales of seconds or longer, such as stream segregation.

  10. Turning art into mere illustration: concretizing art renders its influence context dependent.

    Science.gov (United States)

    Hagtvedt, Henrik; Patrick, Vanessa M

    2011-12-01

    Broadly speaking, artworks are accorded a special significance and are recognized as powerful communication tools. In the current research, the authors posit that the "specialness" of artworks may be diminished simply by emphasizing that which is depicted in them. This emphasis results in the artwork being viewed as a mere illustration rather than a work of art. Specifically, the influence of an "artwork as art" is context independent, but the influence of an "artwork as illustration" is context dependent. The authors demonstrate this phenomenon in two experiments, in the context of products associated with artworks. In a third experiment, they further demonstrate that an abstract (concrete) mind-set aligns with the influence of an artwork as art (illustration).

  11. Context-dependent effect of mood: the regulatory role of personality

    Directory of Open Access Journals (Sweden)

    Zajusz-Gawędzka Dominika

    2015-03-01

    Full Text Available This study explored the influence of the context-dependent effect of mood as well as individual differences in neuroticism and action vs. state/volatility orientation on predecisional processing in a multiattribute choice task. One hundred and twenty participants acquired information about choice options after filling out personality questionnaires. Results showed that participants in a positive mood processed the information longer in enjoy than in done-enough context. In turn, participants in a negative mood processed the information more selectively in enjoy than in done-enough context. It also appeared that this effect is reinforced for participants with low neuroticism and volatility orientation, while it is weakened for those with low neuroticism and action orientation. Results were interpreted in accordance with the differential-processual approach.

  12. Vasotocin Actions on Electric Behavior: Interspecific, Seasonal, and Social Context-Dependent Differences

    Science.gov (United States)

    Perrone, Rossana; Batista, Gervasio; Lorenzo, Daniel; Macadar, Omar; Silva, Ana

    2010-01-01

    Social behavior diversity is correlated with distinctively distributed patterns of a conserved brain network, which depend on the action of neuroendocrine messengers that integrate extrinsic and intrinsic cues. Arginine vasotocin (AVT) is a key integrator underlying differences in behavior across vertebrate taxa. Weakly electric fish use their electric organ discharges (EODs) as social behavioral displays. We examined the effect of AVT on EOD rate in two species of Gymnotiformes with different social strategies: Gymnotus omarorum, territorial and highly aggressive, and Brachyhypopomus gauderio, gregarious and aggressive only between breeding males. AVT induced a long-lasting and progressive increase of EOD rate in isolated B. gauderio, partially blocked by the V1a AVT receptor antagonist (Manning compound, MC), and had no effects in G. omarorum. AVT also induced a long-lasting increase in the firing rate (prevented by MC) of the isolated medullary pacemaker nucleus (PN) of B. gauderio when tested in an in vitro preparation, indicating that the PN is the direct effector of AVT actions. AVT is involved in the seasonal, social context-dependent nocturnal increase of EOD rate that has been recently described in B. gauderio to play a role in mate selection. AVT produced the additional nocturnal increase of EOD rate in non-breeding males, whereas MC blocked it in breeding males. Also, AVT induced a larger EOD rate increase in reproductive dyads than in agonistic encounters. We demonstrated interspecific, seasonal, and context-dependent actions of AVT on the PN that contribute to the understanding of the mechanisms the brain uses to shape sociality. PMID:20802858

  13. Context-dependent autoprocessing of human immunodeficiency virus type 1 protease precursors.

    Directory of Open Access Journals (Sweden)

    ChihFeng Tien

    Full Text Available HIV-1 protease autoprocessing is responsible for liberation of free mature protease (PR from the Gag-Pol polyprotein precursor. A cell-based model system was previously developed to examine the autoprocessing mechanism of fusion precursors carrying the p6*-PR miniprecursor sandwiched between various proteins or epitopes. We here report that precursor autoprocessing is context-dependent as its activity and outcomes can be modulated by sequences upstream of p6*-PR. This was exemplified by the 26aa maltose binding protein (MBP signal peptide (SigP when placed at the N-terminus of a fusion precursor. The mature PRs released from SigP-carrying precursors are resistant to self-degradation whereas those released from SigP-lacking fusion precursors are prone to self-degradation. A H69D mutation in PR abolished autoprocessing of SigP-containing fusion precursors whereas it only partially suppressed autoprocessing of fusion precursors lacking SigP. An autoprocessing deficient GFP fusion precursor with SigP exhibited a subcellular distribution pattern distinct from the one without it in transfected HeLa cells. Furthermore, a SigP fusion precursor carrying a substitution at the P1 position released the mature PR and PR-containing fragments that were different from those released from the precursor carrying the same mutation but lacking SigP. We also examined autoprocessing outcomes in viral particles produced by a NL4-3 derived proviral construct and demonstrated the existence of several PR-containing fragments along with the mature PR. Some of these resembled the SigP precursor autoprocessing outcomes. This finding of context-dependent modulation reveals the complexity of precursor autoprocessing regulation that most likely accompanies sequence variation imposed by the evolution of the upstream Gag moiety.

  14. Vasotocin actions on electric behavior: interspecific, seasonal, and social context-dependent differences

    Directory of Open Access Journals (Sweden)

    Rossana Perrone

    2010-08-01

    Full Text Available Social behavior diversity is correlated with distinctively distributed patterns of a conserved brain network, which depend on the action of neuroendocrine messengers that integrate extrinsic and intrinsic cues. Arginine-vasotocin (AVT is a key integrator underlying differences in behavior across vertebrate taxa. Weakly electric fish use their electric organ discharges (EODs as social behavioral displays. We examined the effect of AVT on EOD rate in two species of Gymnotiformes with different social strategies: Gymnotus omarorum, territorial and highly aggressive, and Brachyhypopomus gauderio, gregarious and aggressive only between breeding males. AVT induced a long-lasting and progressive increase of EOD rate in isolated B. gauderio, partially blocked by the V1a AVT receptor antagonist (Manning compound, MC, and had no effects in G. omarorum. AVT also induced a long-lasting increase in the firing rate (prevented by MC of the isolated medullary pacemaker nucleus (PN of B. gauderio when tested in an in vitro preparation, indicating that the PN is the direct effector of AVT actions. AVT is involved in the seasonal, social context-dependent nocturnal increase of EOD rate that has been recently described in B. gauderio to play a role in mate selection. AVT produced the additional nocturnal increase of EOD rate in non-breeding males, whereas MC blocked it in breeding males. Also, AVT induced a larger EOD rate increase in reproductive dyads than in agonistic encounters. We demonstrated interspecific, seasonal, and context-dependent actions of AVT on the PN that contribute to the understanding of the mechanisms the brain uses to shape sociality.

  15. Demographic responses to weather fluctuations are context dependent in a long-lived amphibian.

    Science.gov (United States)

    Cayuela, Hugo; Arsovski, Dragan; Thirion, Jean-Marc; Bonnaire, Eric; Pichenot, Julian; Boitaud, Sylvain; Miaud, Claude; Joly, Pierre; Besnard, Aurélien

    2016-08-01

    Weather fluctuations have been demonstrated to affect demographic traits in many species. In long-lived organisms, their impact on adult survival might be buffered by the evolution of traits that reduce variation in interannual adult survival. For example, skipping breeding is an effective behavioral mechanism that may limit yearly variation in adult survival when harsh weather conditions occur; however, this in turn would likely lead to strong variation in recruitment. Yet, only a few studies to date have examined the impact of weather variation on survival, recruitment and breeding probability simultaneously in different populations of the same species. To fill this gap, we studied the impact of spring temperatures and spring rainfall on survival, on reproductive skipping behavior and on recruitment in five populations of a long-lived amphibian, the yellow-bellied toad (Bombina variegata). Based on capture-recapture data, our findings demonstrate that survival depends on interactions between age, population and weather variation. Varying weather conditions in the spring result in strong variation in the survival of immature toads, whereas they have little effect on adult toads. Breeding probability depends on both the individual's previous reproductive status and on the weather conditions during the current breeding season, leading to high interannual variation in recruitment. Crucially, we found that the impact of weather variation on demographic traits is largely context dependent and may thus differ sharply between populations. Our results suggest that studies predicting the impact of climate change on population dynamics should be taken with caution when the relationship between climate and demographic traits is established using only one population or few populations. We therefore highly recommend further research that includes surveys replicated in a substantial number of populations to account for context-dependent variation in demographic processes.

  16. Cell Context Dependent p53 Genome-Wide Binding Patterns and Enrichment at Repeats

    Science.gov (United States)

    Botcheva, Krassimira; McCorkle, Sean R.

    2014-01-01

    The p53 ability to elicit stress specific and cell type specific responses is well recognized, but how that specificity is established remains to be defined. Whether upon activation p53 binds to its genomic targets in a cell type and stress type dependent manner is still an open question. Here we show that the p53 binding to the human genome is selective and cell context-dependent. We mapped the genomic binding sites for the endogenous wild type p53 protein in the human cancer cell line HCT116 and compared them to those we previously determined in the normal cell line IMR90. We report distinct p53 genome-wide binding landscapes in two different cell lines, analyzed under the same treatment and experimental conditions, using the same ChIP-seq approach. This is evidence for cell context dependent p53 genomic binding. The observed differences affect the p53 binding sites distribution with respect to major genomic and epigenomic elements (promoter regions, CpG islands and repeats). We correlated the high-confidence p53 ChIP-seq peaks positions with the annotated human repeats (UCSC Human Genome Browser) and observed both common and cell line specific trends. In HCT116, the p53 binding was specifically enriched at LINE repeats, compared to IMR90 cells. The p53 genome-wide binding patterns in HCT116 and IMR90 likely reflect the different epigenetic landscapes in these two cell lines, resulting from cancer-associated changes (accumulated in HCT116) superimposed on tissue specific differences (HCT116 has epithelial, while IMR90 has mesenchymal origin). Our data support the model for p53 binding to the human genome in a highly selective manner, mobilizing distinct sets of genes, contributing to distinct pathways. PMID:25415302

  17. The maintenance of sperm variability: context-dependent selection on sperm morphology in a broadcast spawning invertebrate.

    Science.gov (United States)

    Johnson, Darren W; Monro, Keyne; Marshall, Dustin J

    2013-05-01

    Why are sperm so variable despite having a singular, critical function and an intimate relationship with fitness? A key to understanding the evolution of sperm morphology is identifying which traits enable sperm to be successful fertilizers. Several sperm traits (e.g., tail length, overall size) are implicated in sperm performance, but the benefits of these traits are likely to be highly context dependent. Here, we examined phenotypic selection on sperm morphology of a broadcast spawning tube worm (Galeolaria gemineoa). We conducted laboratory experiments to measure the relationship between average sperm morphology and relative fertilization success across a range of sperm environments that were designed to approximate the range of sperm concentrations and ages encountered by eggs in nature. We found that the strength and form of multivariate selection varied substantially across our environmental gradients. Sperm with long tails and small heads were favored in high-concentration environments, whereas sperm with long heads were favored at low concentrations and old ages. We suggest variation in the local fertilization environment and resulting differences in selection can preserve variability in sperm morphology both within and among males. © 2012 The Author(s). Evolution © 2012 The Society for the Study of Evolution.

  18. Individual differences in context-dependent effects reveal common mechanisms underlying the direction aftereffect and direction repulsion.

    Science.gov (United States)

    McGovern, David P; Walsh, Kevin S; Bell, Jason; Newell, Fiona N

    2017-12-01

    Both spatial and temporal context influence our perception of visual stimuli. For instance, both nearby moving stimuli and recently viewed motion can lead to biases in the perceived direction of a moving stimulus. Due to similarities in the spatial tuning properties of these spatial and temporal context-dependent effects, it is often assumed that they share a functional goal in motion processing and arise from common neural mechanisms. However, the psychophysical evidence concerning this assumption is inconsistent. Here we used an individual differences approach to examine the relationship between different effects of contextual modulation on perception. We reasoned that if measures of contextual modulation share a common underlying mechanism, they should exhibit a strong positive correlation across participants. To test this hypothesis, estimates of the direction aftereffect, direction repulsion, the tilt aftereffect and contrast adaptation were obtained from 54 healthy participants. Our results show pronounced interindividual differences in the effect sizes of all four tasks. Furthermore, there was a strong positive correlation between the estimates of the direction aftereffect and direction repulsion. This correlation was also evident in the threshold elevations that accompanied these repulsive biases in perceived direction. While the effects of contrast adaptation did not correlate with any of the other tasks, there was a weak, but non-significant, correlation between the direction and tilt aftereffects. These results provide evidence for common mechanisms underlying the direction aftereffect and direction repulsion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Pitfalls of the most commonly used models of context dependent substitution

    Directory of Open Access Journals (Sweden)

    Huttley Gavin A

    2008-12-01

    Full Text Available Abstract Background Neighboring nucleotides exert a striking influence on mutation, with the hypermutability of CpG dinucleotides in many genomes being an exemplar. Among the approaches employed to measure the relative importance of sequence neighbors on molecular evolution have been continuous-time Markov process models for substitutions that treat sequences as a series of independent tuples. The most widely used examples are the codon substitution models. We evaluated the suitability of derivatives of the nucleotide frequency weighted (hereafter NF and tuple frequency weighted (hereafter TF models for measuring sequence context dependent substitution. Critical properties we address are their relationships to an independent nucleotide process and the robustness of parameter estimation to changes in sequence composition. We then consider the impact on inference concerning dinucleotide substitution processes from application of these two forms to intron sequence alignments from primates. Results We prove that the NF form always nests the independent nucleotide process and that this is not true for the TF form. As a consequence, using TF to study context effects can be misleading, which is shown by both theoretical calculations and simulations. We describe a simple example where a context parameter estimated under TF is confounded with composition terms unless all sequence states are equi-frequent. We illustrate this for the dinucleotide case by simulation under a nucleotide model, showing that the TF form identifies a CpG effect when none exists. Our analysis of primate introns revealed that the effect of nucleotide neighbors is over-estimated under TF compared with NF. Parameter estimates for a number of contexts are also strikingly discordant between the two model forms. Conclusion Our results establish that the NF form should be used for analysis of independent-tuple context dependent processes. Although neighboring effects in general are

  20. Pitfalls of the most commonly used models of context dependent substitution.

    Science.gov (United States)

    Lindsay, Helen; Yap, Von Bing; Ying, Hua; Huttley, Gavin A

    2008-12-16

    Neighboring nucleotides exert a striking influence on mutation, with the hypermutability of CpG dinucleotides in many genomes being an exemplar. Among the approaches employed to measure the relative importance of sequence neighbors on molecular evolution have been continuous-time Markov process models for substitutions that treat sequences as a series of independent tuples. The most widely used examples are the codon substitution models. We evaluated the suitability of derivatives of the nucleotide frequency weighted (hereafter NF) and tuple frequency weighted (hereafter TF) models for measuring sequence context dependent substitution. Critical properties we address are their relationships to an independent nucleotide process and the robustness of parameter estimation to changes in sequence composition. We then consider the impact on inference concerning dinucleotide substitution processes from application of these two forms to intron sequence alignments from primates. We prove that the NF form always nests the independent nucleotide process and that this is not true for the TF form. As a consequence, using TF to study context effects can be misleading, which is shown by both theoretical calculations and simulations. We describe a simple example where a context parameter estimated under TF is confounded with composition terms unless all sequence states are equi-frequent. We illustrate this for the dinucleotide case by simulation under a nucleotide model, showing that the TF form identifies a CpG effect when none exists. Our analysis of primate introns revealed that the effect of nucleotide neighbors is over-estimated under TF compared with NF. Parameter estimates for a number of contexts are also strikingly discordant between the two model forms. Our results establish that the NF form should be used for analysis of independent-tuple context dependent processes. Although neighboring effects in general are still important, prominent influences such as the elevated Cp

  1. Context-dependent effects of noise on echolocation pulse characteristics in free-tailed bats.

    Science.gov (United States)

    Tressler, Jedediah; Smotherman, Michael S

    2009-10-01

    Background noise evokes a similar suite of adaptations in the acoustic structure of communication calls across a diverse range of vertebrates. Echolocating bats may have evolved specialized vocal strategies for echolocating in noise, but also seem to exhibit generic vertebrate responses such as the ubiquitous Lombard response. We wondered how bats balance generic and echolocation-specific vocal responses to noise. To address this question, we first characterized the vocal responses of flying free-tailed bats (Tadarida brasiliensis) to broadband noises varying in amplitude. Secondly, we measured the bats' responses to band-limited noises that varied in the extent of overlap with their echolocation pulse bandwidth. We hypothesized that the bats' generic responses to noise would be graded proportionally with noise amplitude, total bandwidth and frequency content, and consequently that more selective responses to band-limited noise such as the jamming avoidance response could be explained by a linear decomposition of the response to broadband noise. Instead, the results showed that both the nature and the magnitude of the vocal responses varied with the acoustic structure of the outgoing pulse as well as non-linearly with noise parameters. We conclude that free-tailed bats utilize separate generic and specialized vocal responses to noise in a context-dependent fashion.

  2. Context-dependent effects of noise on echolocation pulse characteristics in free-tailed bats

    Science.gov (United States)

    Smotherman, Michael S.

    2010-01-01

    Background noise evokes a similar suite of adaptations in the acoustic structure of communication calls across a diverse range of vertebrates. Echolocating bats may have evolved specialized vocal strategies for echolocating in noise, but also seem to exhibit generic vertebrate responses such as the ubiquitous Lombard response. We wondered how bats balance generic and echolocation-specific vocal responses to noise. To address this question, we first characterized the vocal responses of flying free-tailed bats (Tadarida brasiliensis) to broadband noises varying in amplitude. Secondly, we measured the bats’ responses to band-limited noises that varied in the extent of overlap with their echolocation pulse bandwidth. We hypothesized that the bats’ generic responses to noise would be graded proportionally with noise amplitude, total bandwidth and frequency content, and consequently that more selective responses to band-limited noise such as the jamming avoidance response could be explained by a linear decomposition of the response to broadband noise. Instead, the results showed that both the nature and the magnitude of the vocal responses varied with the acoustic structure of the outgoing pulse as well as non-linearly with noise parameters. We conclude that free-tailed bats utilize separate generic and specialized vocal responses to noise in a context-dependent fashion. PMID:19672604

  3. Comparative Analysis of Context-Dependent Mutagenesis Using Human and Mouse Models

    Directory of Open Access Journals (Sweden)

    Sofya A. Medvedeva

    2013-01-01

    Full Text Available Substitution rates strongly depend on their nucleotide context. One of the most studied examples is the excess of C > T mutations in the CG context in various groups of organisms, including vertebrates. Studies on the molecular mechanisms underlying this mutation regularity have provided insights into evolution, mutagenesis, and cancer development. Recently several other hypermutable motifs were identified in the human genome. There is an increased frequency of T > C mutations in the second position of the words ATTG and ATAG and an increased frequency of A > C mutations in the first position of the word ACAA. For a better understanding of evolution, it is of interest whether these mutation regularities are human specific or present in other vertebrates, as their presence might affect the validity of currently used substitution models and molecular clocks. A comprehensive analysis of mutagenesis in 4 bp mutation contexts requires a vast amount of mutation data. Such data may be derived from the comparisons of individual genomes or from single nucleotide polymorphism (SNP databases. Using this approach, we performed a systematical comparison of mutation regularities within 2–4 bp contexts in Mus musculus and Homo sapiens and uncovered that even closely related organisms may have notable differences in context-dependent mutation regularities.

  4. Single genome retrieval of context-dependent variability in mutation rates for human germline.

    Science.gov (United States)

    Sahakyan, Aleksandr B; Balasubramanian, Shankar

    2017-01-13

    Accurate knowledge of the core components of substitution rates is of vital importance to understand genome evolution and dynamics. By performing a single-genome and direct analysis of 39,894 retrotransposon remnants, we reveal sequence context-dependent germline nucleotide substitution rates for the human genome. The rates are characterised through rate constants in a time-domain, and are made available through a dedicated program (Trek) and a stand-alone database. Due to the nature of the method design and the imposed stringency criteria, we expect our rate constants to be good estimates for the rates of spontaneous mutations. Benefiting from such data, we study the short-range nucleotide (up to 7-mer) organisation and the germline basal substitution propensity (BSP) profile of the human genome; characterise novel, CpG-independent, substitution prone and resistant motifs; confirm a decreased tendency of moieties with low BSP to undergo somatic mutations in a number of cancer types; and, produce a Trek-based estimate of the overall mutation rate in human. The extended set of rate constants we report may enrich our resources and help advance our understanding of genome dynamics and evolution, with possible implications for the role of spontaneous mutations in the emergence of pathological genotypes and neutral evolution of proteomes.

  5. Context dependence of students' views about the role of equations in understanding biology.

    Science.gov (United States)

    Watkins, Jessica; Elby, Andrew

    2013-06-01

    Students' epistemological views about biology--their ideas about what "counts" as learning and understanding biology--play a role in how they approach their courses and respond to reforms. As introductory biology courses incorporate more physics and quantitative reasoning, student attitudes about the role of equations in biology become especially relevant. However, as documented in research in physics education, students' epistemologies are not always stable and fixed entities; they can be dynamic and context-dependent. In this paper, we examine an interview with an introductory student in which she discusses the use of equations in her reformed biology course. In one part of the interview, she expresses what sounds like an entrenched negative stance toward the role equations can play in understanding biology. However, later in the interview, when discussing a different biology topic, she takes a more positive stance toward the value of equations. These results highlight how a given student can have diverse ways of thinking about the value of bringing physics and math into biology. By highlighting how attitudes can shift in response to different tasks, instructional environments, and contextual cues, we emphasize the need to attend to these factors, rather than treating students' beliefs as fixed and stable.

  6. Is Male Androphilia a Context-Dependent Cross-Cultural Universal?

    Science.gov (United States)

    Hames, Raymond; Garfield, Zachary; Garfield, Melissa

    2017-01-01

    The cross-cultural ethnographic literature has traditionally used the label male "homosexuality" to describe sexual relationships between biological males without considering whether or not the concept encompasses primary sexual attraction to adult males. Although male androphilia seems to be found in all national populations, its universal existence in tribal populations has been questioned. Our goal is to review previous cross-cultural classifications and surveys of male same sex behavior to present a system that does justice to its varied expressions, especially as it is informed by contemporary sexuality research. Previous comparative research does not effectively distinguish male same sex behavior from male androphilia. Using the standard cross-cultural sample (SCCS) as a sampling frame and the ethnographic sources in the human relations area files and elsewhere, we present distributional data on various forms of male same sex behavior. The SCCS is useful because it is designed to be representative of all historically known social formations and the sample is designed to reduce similarities as a consequence of common descent or historical origin as well as reduce the probability of diffusion of sociocultural practices from one culture to another. Our results show that male same sex behavior as well as male androphilia is much more common than previously estimated in the SCCS. With our findings, we make an argument that male androphilia is a context-dependent cross-cultural universal.

  7. Colour cues or spatial cues? Context-dependent preferences in the European greenfinch (Carduelis chloris).

    Science.gov (United States)

    Herborn, Katherine; Alexander, Lucille; Arnold, Kathryn E

    2011-03-01

    Using featural cues such as colour to identify ephemeral food can increase foraging efficiency. Featural cues may change over time however; therefore, animals should use spatial cues to relocate food that occurs in a temporally stable position. We tested this hypothesis by measuring the cue preferences of captive greenfinches Carduelis chloris when relocating food hidden in a foraging tray. In these standardised associative learning trials, greenfinches favoured colour cues when returning to a foraging context that they had encountered before only once ("one-trial test") but switched to spatial cues when they had encountered that scenario on ten previous occasions ("repeated-trial test"). We suggest that repeated encounters generated a context in which individuals had a prior expectation of temporal stability, and hence context-dependent cue selection. Next, we trained birds to find food in the absence of colour cues but tested them in the presence of visual distracters. Birds were able to learn spatial cues after one encounter, but only when visual distracters were identical in colouration. When a colourful distracter was present in the test phase, cue selection was random. Unlike the first one-trial test, birds were not biased towards this colourful visual distracter. Together, these results suggest that greenfinches are able to learn both cue types, colour cue biases represent learning, not simply distraction, and spatial cues are favoured over colour cues only in temporally stable contexts. © Springer-Verlag 2010

  8. Seed harvesting by a generalist consumer is context-dependent: Interactive effects across multiple spatial scales

    Science.gov (United States)

    Ostoja, Steven M.; Schupp, Eugene W.; Klinger, Rob

    2013-01-01

    Granivore foraging decisions affect consumer success and determine the quantity and spatial pattern of seed survival. These decisions are influenced by environmental variation at spatial scales ranging from landscapes to local foraging patches. In a field experiment, the effects of seed patch variation across three spatial scales on seed removal by western harvester ants Pogonomyrmex occidentalis were evaluated. At the largest scale we assessed harvesting in different plant communities, at the intermediate scale we assessed harvesting at different distances from ant mounds, and at the smallest scale we assessed the effects of interactions among seed species in local seed neighborhoods on seed harvesting (i.e. resource–consumer interface). Selected seed species were presented alone (monospecific treatment) and in mixture with Bromus tectorum (cheatgrass; mixture treatment) at four distances from P. occidentalis mounds in adjacent intact sagebrush and non-native cheatgrass-dominated communities in the Great Basin, Utah, USA. Seed species differed in harvest, with B. tectorum being least preferred. Large and intermediate scale variation influenced harvest. More seeds were harvested in sagebrush than in cheatgrass-dominated communities (largest scale), and the quantity of seed harvested varied with distance from mounds (intermediate-scale), although the form of the distance effect differed between plant communities. At the smallest scale, seed neighborhood affected harvest, but the patterns differed among seed species considered. Ants harvested fewer seeds from mixed-seed neighborhoods than from monospecific neighborhoods, suggesting context dependence and potential associational resistance. Further, the effects of plant community and distance from mound on seed harvest in mixtures differed from their effects in monospecific treatments. Beyond the local seed neighborhood, selection of seed resources is better understood by simultaneously evaluating removal at

  9. Dental hygienists' perceptions of professionalism are multidimensional and context-dependent: a qualitative study in Japan.

    Science.gov (United States)

    Nagatani, Yukiko; Imafuku, Rintaro; Takemoto, Toshinobu; Waki, Tadayuki; Obayashi, Taiji; Ogawa, Tetsuji

    2017-12-29

    Due to the declining birth rate and aging of Japanese society, the roles and responsibilities of dental hygienists are continuously expanding. Medical professionalism needs to be pursued continuously throughout one's career in order to improve dental care and treatment. Although conceptualising professionalism is essential to the education of health professionals, professionalism in the field of dental hygiene has not been defined or adequately examined in Japan. The purposes of this study are to investigate dental hygienists' perceptions of the constituent elements of professionalism and the factors affecting their perceptions. Semi-structured interviews were conducted with 18 dental hygienists in Japan. Drawing on the conceptualisation of professionalism in medicine described by Van de Camp et al., the transcribed data were thematically analysed. The dental hygienists in this study perceived 70 constituent elements that were categorised into eight core competencies related to professionalism. These competencies were further classified into three main themes: intrapersonal, interpersonal, and public professionalism. There were three sociohistorical factors that affected their perceptions of the constituent elements, namely academic background (university or technical school), the contexts of any previously provided dental care (university hospital or dental clinic), and their social interactions with their colleagues during their engagement in dental practice (dental team or interprofessional team). Moreover, according to their sociohistorical backgrounds, the dental hygienists saw themselves variously as scholars (university graduates), facilitators (university hospital), skillful artisans (dental clinic), or collaborators (interprofessional team). Dental hygienists' perceptions of professionalism are multidimensional and context-dependent, so culture- and professional-specific elements need to be included in educational curricula and continuing professional

  10. Context-dependent flight speed: evidence for energetically optimal flight speed in the bat Pipistrellus kuhlii?

    Science.gov (United States)

    Grodzinski, Uri; Spiegel, Orr; Korine, Carmi; Holderied, Marc W

    2009-05-01

    at a context-dependent, energetically optimal flight speed.

  11. Value-based attentional capture influences context-dependent decision-making.

    Science.gov (United States)

    Itthipuripat, Sirawaj; Cha, Kexin; Rangsipat, Napat; Serences, John T

    2015-07-01

    Normative theories posit that value-based decision-making is context independent. However, decisions between two high-value options can be suboptimally biased by the introduction of a third low-value option. This context-dependent modulation is consistent with the divisive normalization of the value of each stimulus by the total value of all stimuli. In addition, an independent line of research demonstrates that pairing a stimulus with a high-value outcome can lead to attentional capture that can mediate the efficiency of visual information processing. Here we tested the hypothesis that value-based attentional capture interacts with value-based normalization to influence the optimality of decision-making. We used a binary-choice paradigm in which observers selected between two targets and the color of each target indicated the magnitude of their reward potential. Observers also had to simultaneously ignore a task-irrelevant distractor rendered in a color that was previously associated with a specific reward magnitude. When the color of the task-irrelevant distractor was previously associated with a high reward, observers responded more slowly and less optimally. Moreover, as the learned value of the distractor increased, electrophysiological data revealed an attenuation of the lateralized N1 and N2Pc responses evoked by the relevant choice stimuli and an attenuation of the late positive deflection (LPD). Collectively, these behavioral and electrophysiological data suggest that value-based attentional capture and value-based normalization jointly mediate the influence of context on free-choice decision-making. Copyright © 2015 the American Physiological Society.

  12. Nitric oxide regulates input specificity of long-term depression and context dependence of cerebellar learning.

    Directory of Open Access Journals (Sweden)

    Hideaki Ogasawara

    2007-01-01

    Full Text Available Recent studies have shown that multiple internal models are acquired in the cerebellum and that these can be switched under a given context of behavior. It has been proposed that long-term depression (LTD of parallel fiber (PF-Purkinje cell (PC synapses forms the cellular basis of cerebellar learning, and that the presynaptically synthesized messenger nitric oxide (NO is a crucial "gatekeeper" for LTD. Because NO diffuses freely to neighboring synapses, this volume learning is not input-specific and brings into question the biological significance of LTD as the basic mechanism for efficient supervised learning. To better characterize the role of NO in cerebellar learning, we simulated the sequence of electrophysiological and biochemical events in PF-PC LTD by combining established simulation models of the electrophysiology, calcium dynamics, and signaling pathways of the PC. The results demonstrate that the local NO concentration is critical for induction of LTD and for its input specificity. Pre- and postsynaptic coincident firing is not sufficient for a PF-PC synapse to undergo LTD, and LTD is induced only when a sufficient amount of NO is provided by activation of the surrounding PFs. On the other hand, above-adequate levels of activity in nearby PFs cause accumulation of NO, which also allows LTD in neighboring synapses that were not directly stimulated, ruining input specificity. These findings lead us to propose the hypothesis that NO represents the relevance of a given context and enables context-dependent selection of internal models to be updated. We also predict sparse PF activity in vivo because, otherwise, input specificity would be lost.

  13. Context dependent memory in two learning environments: the tutorial room and the operating theatre.

    Science.gov (United States)

    Coveney, Andrew P; Switzer, Timothy; Corrigan, Mark A; Redmond, Henry P

    2013-09-01

    Psychologists have previously demonstrated that information recall is context dependent. However, how this influences the way we deliver medical education is unclear. This study aimed to determine if changing the recall context from the learning context affects the ability of medical students to recall information. Using a free recall experimental model, fourteen medical student participants were administered audio lists of 30 words in two separate learning environments, a tutorial room and an operating theatre. They were then asked to recall the words in both environments. While in the operating theatre participants wore appropriate surgical clothing and assembled around an operating table. While in the tutorial room, participants dressed casually and were seated around a table. Students experienced the same duration (15 minutes) and disruption in both environments. The mean recall score from the 28 tests performed in the same environment was 12.96 +/- 3.93 (mean, SD). The mean recall score from the 28 tests performed in an alternative environment to the learning episode was 13.5 +/- 5.31(mean, SD), indicating that changing the recall environment from the learning environment does not cause any statistical difference (p=0.58). The average recall score of participants who learned and recalled in the tutorial room was 13.0 +/- 3.84 (mean, SD). The average recall score of participants who learnt and recalled in the operating theatre was 12.92 +/- 4.18 (mean, SD), representing no significant difference between the two environments for learning (p=0.4792). The results support the continued use of tutorial rooms and operating theatres as appropriate environments in which to teach medical students, with no significant difference in information recall seen either due to a same context effect or specific context effect.

  14. A Context-Dependent View on the Linguistic Interdependence Hypothesis: Language Use and SES as Potential Moderators

    Science.gov (United States)

    Prevoo, Mariëlle J. L.; Malda, Maike; Emmen, Rosanneke A. G.; Yeniad, Nihal; Mesman, Judi

    2015-01-01

    The linguistic interdependence hypothesis states that the development of skills in a second language (L2) partly depends on the skill level in the first language (L1). It has been suggested that the theory lacked attention for differential interdependence. In this study we test what we call the hypothesis of context-dependent linguistic…

  15. Effects of extended context discrimination training and context extinction on transfer of context dependency of conditioned flavor aversion.

    Science.gov (United States)

    Iguchi, Yoshio; Fukumoto, Kazuya; Sawa, Kosuke; Ishii, Kiyoshi

    2014-03-01

    We trained rats in a context discrimination paradigm by pairing a sucrose solution with lithium chloride in one context (conditioning context) and simple exposure to the same fluid in a second (neutral) context to establish a context-dependent aversion to the conditioned fluid. We then investigated whether transfer of the context dependency to a test fluid (a sodium chloride solution) was affected by two post-discrimination training treatments, an extended context discrimination training, and non-reinforced exposure to the conditioning context (context extinction). We found that the context-dependent flavor aversion that had been specific to sucrose transferred to the test fluid after the extensive training (Experiment 1). Context extinction eliminated the transfer effect that had been observed immediately after the context discrimination training (Experiment 2). In addition, an aversion acquired by sucrose through a simple conditioning of sucrose-LiCl pairings did not generalize to the test fluid (Experiment 3). These results emphasize the importance of a Pavlovian excitatory association between the conditioning context and nausea as a primary source of transfer of the context dependency, rather than a generalization of aversion acquired by the conditioned fluid to the test fluid. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Strain- and context-dependent effects of the anandamide hydrolysis inhibitor URB597 on social behavior in rats

    NARCIS (Netherlands)

    Manduca, A.; Servadio, M.; Campolongo, P.; Palmery, M.; Trabace, L.; Vanderschuren, L.J.M.J.; Cuomo, V; Trezza, V.

    2014-01-01

    Genetic and environmental factors play an important role in the cannabinoid modulation of motivation and emotion. Therefore, the aim of the present study was to test whether anandamide modulation of social behavior is strain- and context-dependent. We tested the effects of the anandamide hydrolysis

  17. Predator-Prey Interactions are Context Dependent in a Grassland Plant-Grasshopper-Wolf Spider Food Chain.

    Science.gov (United States)

    Laws, Angela N; Joern, Anthony

    2015-06-01

    Species interactions are often context dependent, where outcomes vary in response to one or more environmental factors. It remains unclear how abiotic conditions like temperature combine with biotic factors such as consumer density or food quality to affect resource availability or influence species interactions. Using the large grasshopper Melanoplus bivittatus (Say) and a common wolf spider [Rabidosa rabida (Walkenaer)], we conducted manipulative field experiments in tallgrass prairie to examine how spider-grasshopper interactions respond to manipulations of temperature, grasshopper density, and food quality. Grasshopper survival was density dependent, as were the effects of spider presence and food quality in context-dependent ways. In high grasshopper density treatments, predation resulted in increased grasshopper survival, likely as a result of reduced intraspecific competition in the presence of spiders. Spiders had no effect on grasshopper survival when grasshoppers were stocked at low densities. Effects of the experimental treatments were often interdependent so that effects were only observed when examined together with other treatments. The occurrence of trophic cascades was context dependent, where the effects of food quality and spider presence varied with temperature under high-density treatments. Temperature weakly affected the impact of spider presence on M. bivittatus survivorship when all treatments were considered simultaneously, but different context-dependent responses to spider presence and food quality were observed among the three temperature treatments under high-density conditions. Our results indicate that context-dependent species interactions are common and highlight the importance of understanding how key biotic and abiotic factors combine to influence species interactions. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. The Context-Dependency of the Experience of Auditory Succession and Prospects for Embodying Philosophical Models of Temporal Experience

    Directory of Open Access Journals (Sweden)

    Maria Kon

    2015-05-01

    Full Text Available Recent philosophical work on temporal experience offers generic models that are often assumed to apply to all sensory modalities. I show that the models serve as broad frameworks in which different aspects of cognitive science can be slotted and, thus, are beneficial to furthering research programs in embodied music cognition. Here I discuss a particular feature of temporal experience that plays a key role in such philosophical work: a distinction between the experience of succession and the mere succession of experiences. I question the presupposition that there is such an evident, clear distinction and suggest that, instead, how the distinction is drawn is context-dependent. After suggesting a way to modify the philosophical models of temporal experience to accommodate this context-dependency, I illustrate that these models can fruitfully incorporate features of research projects in embodied musical cognition. To do so I supplement a modified retentionalist model with aspects of recent work that links bodily movement with musical perception (Godøy, 2006; 2010a; Jensenius, Wanderley, Godøy, and Leman, 2010. The resulting model is shown to facilitate novel hypotheses, refine the notion of context-dependency and point towards means of extending the philosophical model and an existent research program.

  19. Context dependency and saturating effects of loss of rare soil microbes on plant productivity

    NARCIS (Netherlands)

    Hol, Gera; De Boer, Wietse; de Hollander, Mattias; Kuramae, Eiko Eurya; Meisner, Annelein; van der Putten, Wim

    2015-01-01

    Land use intensification is associated with loss of biodiversity and altered ecosystem functioning. Until now most studies on the relationship between biodiversity and ecosystem functioning focused on random loss of species, while loss of rare species that usually are the first to disappear received

  20. Context-dependent adaptation improves robustness of myoelectric control for upper-limb prostheses

    Science.gov (United States)

    Patel, Gauravkumar K.; Hahne, Janne M.; Castellini, Claudio; Farina, Dario; Dosen, Strahinja

    2017-10-01

    Objective. Dexterous upper-limb prostheses are available today to restore grasping, but an effective and reliable feed-forward control is still missing. The aim of this work was to improve the robustness and reliability of myoelectric control by using context information from sensors embedded within the prosthesis. Approach. We developed a context-driven myoelectric control scheme (cxMYO) that incorporates the inference of context information from proprioception (inertial measurement unit) and exteroception (force and grip aperture) sensors to modulate the outputs of myoelectric control. Further, a realistic evaluation of the cxMYO was performed online in able-bodied subjects using three functional tasks, during which the cxMYO was compared to a purely machine-learning-based myoelectric control (MYO). Main results. The results demonstrated that utilizing context information decreased the number of unwanted commands, improving the performance (success rate and dropped objects) in all three functional tasks. Specifically, the median number of objects dropped per round with cxMYO was zero in all three tasks and a significant increase in the number of successful transfers was seen in two out of three functional tasks. Additionally, the subjects reported better user experience. Significance. This is the first online evaluation of a method integrating information from multiple on-board prosthesis sensors to modulate the output of a machine-learning-based myoelectric controller. The proposed scheme is general and presents a simple, non-invasive and cost-effective approach for improving the robustness of myoelectric control.

  1. Context dependency and saturating effects of loss of rare soil microbes on plant productivity

    Directory of Open Access Journals (Sweden)

    Gera eHol

    2015-06-01

    Full Text Available Land use intensification is associated with loss of biodiversity and altered ecosystem functioning. Until now most studies on the relationship between biodiversity and ecosystem functioning focused on random loss of species, while loss of rare species that usually are the first to disappear received less attention. Here we test if the effect of rare microbial species loss on plant productivity depends on the origin of the microbial soil community. Soils were sampled from three land use types at two farms. Microbial communities with increasing loss of rare species were created by inoculating sterilized soils with serially diluted soil suspensions. After 8 months of incubation, the effects of the different soil communities on abiotic soil properties, soil processes, microbial community composition and plant productivity was measured. Dilution treatments resulted in increasing species loss, which was in relation to abundance of bacteria in the original field soil, without affecting most of the other soil parameters and processes. Microbial species loss affected plant biomass positively, negatively or not at all, depending on soil origin, but not on land use history. Even within fields the effects of dilution on plant biomass varied between replicates, suggesting heterogeneity in microbial community composition. The effects of medium and severe species loss on plant biomass were similar, pointing towards a saturating effect of species loss. We conclude that changes in the composition of the soil microbial community, including rare species loss, can affect plant productivity, depending on the composition of the initial microbial community. Future work on the relation between function and species loss effects should address this variation by including multiple sampling origins.

  2. Context dependency and saturating effects of loss of rare soil microbes on plant productivity.

    Science.gov (United States)

    Hol, W H Gera; de Boer, Wietse; de Hollander, Mattias; Kuramae, Eiko E; Meisner, Annelein; van der Putten, Wim H

    2015-01-01

    Land use intensification is associated with loss of biodiversity and altered ecosystem functioning. Until now most studies on the relationship between biodiversity and ecosystem functioning focused on random loss of species, while loss of rare species that usually are the first to disappear received less attention. Here we test if the effect of rare microbial species loss on plant productivity depends on the origin of the microbial soil community. Soils were sampled from three land use types at two farms. Microbial communities with increasing loss of rare species were created by inoculating sterilized soils with serially diluted soil suspensions. After 8 months of incubation, the effects of the different soil communities on abiotic soil properties, soil processes, microbial community composition, and plant productivity was measured. Dilution treatments resulted in increasing species loss, which was in relation to abundance of bacteria in the original field soil, without affecting most of the other soil parameters and processes. Microbial species loss affected plant biomass positively, negatively or not at all, depending on soil origin, but not on land use history. Even within fields the effects of dilution on plant biomass varied between replicates, suggesting heterogeneity in microbial community composition. The effects of medium and severe species loss on plant biomass were similar, pointing toward a saturating effect of species loss. We conclude that changes in the composition of the soil microbial community, including rare species loss, can affect plant productivity, depending on the composition of the initial microbial community. Future work on the relation between function and species loss effects should address this variation by including multiple sampling origins.

  3. Context-Dependent Development of Lymphoid Stroma from Adult CD34+ Adventitial Progenitors

    DEFF Research Database (Denmark)

    Sitnik, Katarzyna Maria; Wendland, Kerstin; Weishaupt, Holger

    2016-01-01

    ) and thymus that is located within the vascular niche surrounding PDPN-PDGFRβ+/α-Esam-1+ITGA7+ pericytes. CD34+ adventitial cells developed in late embryonic thymus and in postnatal LNs and in the thymus originated, along with pericytes, from a common anlage-seeding progenitor population. Using lymphoid organ......Despite the key role of primary and secondary lymphoid organ stroma in immunity, our understanding of the heterogeneity and ontogeny of these cells remains limited. Here, we identify a functionally distinct subset of BP3-PDPN+PDGFRβ+/α+CD34+ stromal adventitial cells in both lymph nodes (LNs...

  4. Audio visual speech source separation via improved context dependent association model

    Science.gov (United States)

    Kazemi, Alireza; Boostani, Reza; Sobhanmanesh, Fariborz

    2014-12-01

    In this paper, we exploit the non-linear relation between a speech source and its associated lip video as a source of extra information to propose an improved audio-visual speech source separation (AVSS) algorithm. The audio-visual association is modeled using a neural associator which estimates the visual lip parameters from a temporal context of acoustic observation frames. We define an objective function based on mean square error (MSE) measure between estimated and target visual parameters. This function is minimized for estimation of the de-mixing vector/filters to separate the relevant source from linear instantaneous or time-domain convolutive mixtures. We have also proposed a hybrid criterion which uses AV coherency together with kurtosis as a non-Gaussianity measure. Experimental results are presented and compared in terms of visually relevant speech detection accuracy and output signal-to-interference ratio (SIR) of source separation. The suggested audio-visual model significantly improves relevant speech classification accuracy compared to existing GMM-based model and the proposed AVSS algorithm improves the speech separation quality compared to reference ICA- and AVSS-based methods.

  5. High-throughput assessment of context-dependent effects of chromatin proteins.

    Science.gov (United States)

    Brueckner, Laura; van Arensbergen, Joris; Akhtar, Waseem; Pagie, Ludo; van Steensel, Bas

    2016-01-01

    Chromatin proteins control gene activity in a concerted manner. We developed a high-throughput assay to study the effects of the local chromatin environment on the regulatory activity of a protein of interest. The assay combines a previously reported multiplexing strategy based on barcoded randomly integrated reporters with Gal4-mediated tethering. We applied the assay to Drosophila heterochromatin protein 1a (HP1a), which is mostly known as a repressive protein but has also been linked to transcriptional activation. Recruitment to over 1000 genomic locations revealed that HP1a is a potent repressor able to silence even highly expressing reporter genes. However, the local chromatin context can modulate HP1a function. In pericentromeric regions, HP1a-induced repression was enhanced by twofold. In regions marked by a H3K36me3-rich chromatin signature, HP1a-dependent silencing was significantly decreased. We found no evidence for an activating function of HP1a in our experimental system. Furthermore, we did not observe stable transmission of repression over mitotic divisions after loss of targeted HP1a. The multiplexed tethered reporter assay should be applicable to a large number of chromatin proteins and will be a useful tool to dissect combinatorial regulatory interactions in chromatin.

  6. On the context dependence of emotion displays: Perceptions of gold medalists' expressions of pride.

    Science.gov (United States)

    van Osch, Yvette; Zeelenberg, Marcel; Breugelmans, Seger M

    2016-11-01

    In spite of various claims for cross-cultural differences in the experience of pride, studies on the expression of pride have revealed few cross-cultural differences. Five studies using archival data from Olympic and national championships do show cross-cultural differences in the expression of pride and other positive emotions in pride-eliciting contexts, contingent on the social context of the expression, notably the in-group or out-group status of the audience. Chinese gold medalists were perceived to express less pride than American medalists when outperforming in-group competitors; when outperforming out-group members, however, no or smaller cross-cultural differences were observed. These findings are important because they indicate that cultural norms about emotion expression may be activated only in situations in which they serve a function in coordinating people's behaviour.

  7. Context-dependent interactions and the regulation of species richness in freshwater fish

    Science.gov (United States)

    MacDougall, Andrew S.; Harvey, Eric; McCune, Jenny L.; Nilsson, Karin A.; Bennett, Joseph; Firn, Jennifer; Bartley, Timothy; Grace, James B.; Kelly, Jocelyn; Tunney, Tyler D.; McMeans, Bailey; Matsuzaki, Shin-Ichiro S.; Kadoya, Taku; Esch, Ellen; Cazelles, Kevin; Lester, Nigel; McCann, Kevin S.

    2018-01-01

    Species richness is regulated by a complex network of scale-dependent processes. This complexity can obscure the influence of limiting species interactions, making it difficult to determine if abiotic or biotic drivers are more predominant regulators of richness. Using integrative modeling of freshwater fish richness from 721 lakes along an 11olatitudinal gradient, we find negative interactions to be a relatively minor independent predictor of species richness in lakes despite the widespread presence of predators. Instead, interaction effects, when detectable among major functional groups and 231 species pairs, were strong, often positive, but contextually dependent on environment. These results are consistent with the idea that negative interactions internally structure lake communities but do not consistently ‘scale-up’ to regulate richness independently of the environment. The importance of environment for interaction outcomes and its role in the regulation of species richness highlights the potential sensitivity of fish communities to the environmental changes affecting lakes globally.

  8. Multifunctional and context-dependent control of vocal acoustics by individual muscles

    DEFF Research Database (Denmark)

    Srivastava, Kyle H; Elemans, Coen P H; Sober, Samuel J

    2015-01-01

    The relationship between muscle activity and behavioral output determines how the brain controls and modifies complex skills. In vocal control, ensembles of muscles are used to precisely tune single acoustic parameters such as fundamental frequency and sound amplitude. If individual vocal muscles...... parameter. Additionally, it is unknown whether the function of single muscles is fixed or varies across different vocal gestures. A fixed relationship would allow the brain to use the same changes in muscle activation to, for example, increase the fundamental frequency of different vocal gestures, whereas...... recorded electromyographic data from vocal muscles in singing Bengalese finches. Second, we electrically perturbed the activity of single muscles during song. Third, we developed an ex vivo technique to analyze the biomechanical and acoustic consequences of single-muscle perturbations. We found that single...

  9. Stabilization of the genome of the mismatch repair deficient Mycobacterium tuberculosis by context-dependent codon choice.

    Science.gov (United States)

    Wanner, Roger M; Güthlein, Carolin; Springer, Burkhard; Böttger, Erik C; Ackermann, Martin

    2008-05-28

    The rate at which a stretch of DNA mutates is determined by the cellular systems for DNA replication and repair, and by the nucleotide sequence of the stretch itself. One sequence feature with a particularly strong influence on the mutation rate are nucleotide repeats. Some microbial pathogens use nucleotide repeats in their genome to stochastically vary phenotypic traits and thereby evade host defense. However, such unstable sequences also come at a cost, as mutations are often deleterious. Here, we analyzed how these opposing forces shaped genome stability in the human pathogen Mycobacterium tuberculosis. M. tuberculosis lacks a mismatch repair system, and this renders nucleotide repeats particularly unstable. We found that proteins of M. tuberculosis are encoded by using codons in a context-dependent manner that prevents the emergence of nucleotide repeats. This context-dependent codon choice leads to a strong decrease in the estimated frame-shift mutation rate and thus to an increase in genome stability. These results indicate that a context-specific codon choice can partially compensate for the lack of a mismatch repair system, and helps to maintain genome integrity in this pathogen.

  10. Stabilization of the genome of the mismatch repair deficient Mycobacterium tuberculosis by context-dependent codon choice

    Directory of Open Access Journals (Sweden)

    Ackermann Martin

    2008-05-01

    Full Text Available Abstract Background The rate at which a stretch of DNA mutates is determined by the cellular systems for DNA replication and repair, and by the nucleotide sequence of the stretch itself. One sequence feature with a particularly strong influence on the mutation rate are nucleotide repeats. Some microbial pathogens use nucleotide repeats in their genome to stochastically vary phenotypic traits and thereby evade host defense. However, such unstable sequences also come at a cost, as mutations are often deleterious. Here, we analyzed how these opposing forces shaped genome stability in the human pathogen Mycobacterium tuberculosis. M. tuberculosis lacks a mismatch repair system, and this renders nucleotide repeats particularly unstable. Results We found that proteins of M. tuberculosis are encoded by using codons in a context-dependent manner that prevents the emergence of nucleotide repeats. This context-dependent codon choice leads to a strong decrease in the estimated frame-shift mutation rate and thus to an increase in genome stability. Conclusion These results indicate that a context-specific codon choice can partially compensate for the lack of a mismatch repair system, and helps to maintain genome integrity in this pathogen.

  11. Foam nests provide context-dependent thermal insulation to embryos of three leptodactylid frogs.

    Science.gov (United States)

    Méndez-Narváez, J; Flechas, S V; Amézquita, A

    2015-01-01

    The choice of adequate breeding habitat and its associated thermoregulatory conditions are thought to be important in the evolution of amphibian reproductive strategies. Among leptodactylid frogs, there is a terrestrial cline in the oviposition sites chosen to build foam nests for eggs. Although several functions have been attributed to foam nests, their role in temperature regulation for embryos is unclear. Here we tested the hypothesis that foam nests buffer embryos from variation in air temperature. We examined the degree of terrestrial nest sites in three species, finding a terrestrial cline of sites in terms of distance from water. We tested whether this nest-insulation effect varied among these species that differ in the degree of terrestrial nest sites and whether translocating nests impacted embryonic mortality. Our results demonstrate a negative effect of translocating aquatic nests to land, inferred from the highest hatching success in natural nests sites. All nests attenuated environmental thermal variation, but more terrestrial nests buffered embryos from a greater range of temperatures than did aquatic ones. Altogether, our data indicate that foam nests insulate embryos from daily temperature fluctuations among leptodactylid frogs with different degrees of terrestrial nests, which may well have contributed to the evolution of this reproductive strategy.

  12. Context-dependent cell cycle checkpoint abrogation by a novel kinase inhibitor.

    Directory of Open Access Journals (Sweden)

    Andrew J Massey

    2010-10-01

    Full Text Available Checkpoint kinase 1 and 2 (Chk1/Chk2, and the Aurora kinases play a critical role in the activation of the DNA damage response and mitotic spindle checkpoints. We have identified a novel inhibitor of these kinases and utilized this molecule to probe the functional interplay between these two checkpoints.Fragment screening, structure guided design, and kinase cross screening resulted in the identification of a novel, potent small molecule kinase inhibitor (VER-150548 of Chk1 and Chk2 kinases with IC(50s of 35 and 34 nM as well as the Aurora A and Aurora B kinases with IC(50s of 101 and 38 nM. The structural rationale for this kinase specificity could be clearly elucidated through the X-ray crystal structure. In human carcinoma cells, VER-150548 induced reduplication and the accumulation of cells with >4N DNA content, inhibited histone H3 phosphorylation and ultimately gave way to cell death after 120 hour exposure; a phenotype consistent with cellular Aurora inhibition. In the presence of DNA damage induced by cytotoxic chemotherapeutic drugs, VER-150548 abrogated DNA damage induced cell cycle checkpoints. Abrogation of these checkpoints correlated with increased DNA damage and rapid cell death in p53 defective HT29 cells. In the presence of DNA damage, reduplication could not be observed. These observations are consistent with the Chk1 and Chk2 inhibitory activity of this molecule.In the presence of DNA damage, we suggest that VER-150548 abrogates the DNA damage induced checkpoints forcing cells to undergo a lethal mitosis. The timing of this premature cell death induced by Chk1 inhibition negates Aurora inhibition thereby preventing re-entry into the cell cycle and subsequent DNA reduplication. This novel kinase inhibitor therefore serves as a useful chemical probe to further understand the temporal relationship between cell cycle checkpoint pathways, chemotherapeutic agent induced DNA damage and cell death.

  13. Perceived neighborhood ethnic diversity and social outcomes: Context-dependent effects within a postindustrial city undergoing regeneration

    Science.gov (United States)

    Kearns, Ade; Whitley, Elise

    2018-01-01

    ABSTRACT This article examines whether perceived neighborhood ethnic diversity is associated with a range of social outcomes in a postindustrial city undergoing regeneration. The research included a survey in 3 types of deprived area in Glasgow: those undergoing regeneration, those directly adjoining regeneration areas, and those further removed from regeneration areas. In areas undergoing regeneration, perceived diversity was positively associated with many residential, cohesion, safety, and empowerment outcomes. This was also true, although to a lesser extent, in deprived areas at some distance from regeneration areas. In areas immediately surrounding the regeneration areas, perceived diversity had mixed associations with residential and safety outcomes and few associations with cohesion and empowerment outcomes. The results suggest that the effects of perceived diversity are context dependent within a city. Moreover, regeneration processes alter neighborhood contexts and therefore enable scale, timing, and duration of diversity to mediate the relationships between perceived diversity and social outcomes. PMID:29479290

  14. Context Dependent Spectral Unmixing

    Science.gov (United States)

    2014-08-01

    remote sensing [1–13]. It is also used in food safety [14–17], pharmaceutical process monitoring and quality control [18–22], as well as in biomedical...23,24], industrial [25], biometric [26] and forensic applications [27]. Hyperspectral sensors capture both the spatial and spectral information of a...imagery,” IEEE Signal Processing Magazine, vol. 19, no. 1, pp. 58–69, 2002. [12] A. Plaza, J. A. Benediktsson, J. W. Boardman, J. Brazile , L. Bruzzone, G

  15. Context-dependent cheating

    DEFF Research Database (Denmark)

    Pascual‐Ezama, David; Fosgaard, Toke Reinholt; Cardenas, Juan-Camilo

    2015-01-01

    participants. We employ a very simple task where participants face a trade-off between the joy of eating a fine chocolate and the disutility of having a threatened self-concept because of lying. Despite the incentives to cheat, we find that individuals are mostly honest. Further, international indices...

  16. Context-dependent effects of large-wildlife declines on small-mammal communities in central Kenya.

    Science.gov (United States)

    Young, Hillary S; McCauley, Douglas J; Dirzo, Rodolfo; Goheen, Jacob R; Agwanda, Bernard; Brook, Cara; Otarola-Castillo, Erik; Ferguson, Adam W; Kinyua, Stephen N; McDonough, Molly M; Palmer, Todd M; Pringle, Robert M; Young, Truman P; Helgen, Kristofer M

    2015-03-01

    Many species of large wildlife have declined drastically worldwide. These reductions often lead to profound shifts in the ecology of entire communities and ecosystems. However, the effects of these large-wildlife declines on other taxa likely hinge upon both underlying abiotic properties of these systems and on the types of secondary anthropogenic changes associated with wildlife loss, making impacts difficult to predict. To better understand how these important contextual factors determine the consequences of large-wildlife declines on other animals in a community, we examined the effects of three common forms of large-wildlife loss (removal without replacement [using fences], removal followed by replacement with domestic stock, and removal accompanied by crop agricultural use) on small-mammal abundance, diversity, and community composition, in landscapes that varied in several abiotic attributes (rainfall, soil fertility, land-use intensity) in central Kenya. We found that small-mammal communities were indeed heavily impacted by all forms of large-wildlife decline, showing, on average: (1) higher densities, (2) lower species richness per site, and (3) different species assemblages in sites from which large wildlife were removed. However, the nature and magnitude of these effects were strongly context dependent. Rainfall, type of land-use change, and the interaction of these two factors were key predictors of both the magnitude and type of responses of small mammals. The strongest effects, particularly abundance responses, tended to be observed in low-rainfall areas. Whereas isolated wildlife removal primarily led to increased small-mammal abundance, wildlife removal associated with secondary uses (agriculture, domestic stock) had much more variable effects on abundance and stronger impacts on diversity and composition. Collectively, these results (1) highlight the importance of context in determining the impacts of large-wildlife decline on small

  17. Mutation rate, spectrum, topology, and context-dependency in the DNA mismatch repair-deficient Pseudomonas fluorescens ATCC948.

    Science.gov (United States)

    Long, Hongan; Sung, Way; Miller, Samuel F; Ackerman, Matthew S; Doak, Thomas G; Lynch, Michael

    2014-12-23

    High levels of genetic diversity exist among natural isolates of the bacterium Pseudomonas fluorescens, and are especially elevated around the replication terminus of the genome, where strain-specific genes are found. In an effort to understand the role of genetic variation in the evolution of Pseudomonas, we analyzed 31,106 base substitutions from 45 mutation accumulation lines of P. fluorescens ATCC948, naturally deficient for mismatch repair, yielding a base-substitution mutation rate of 2.34 × 10(-8) per site per generation (SE: 0.01 × 10(-8)) and a small-insertion-deletion mutation rate of 1.65 × 10(-9) per site per generation (SE: 0.03 × 10(-9)). We find that the spectrum of mutations in prophage regions, which often contain virulence factors and antibiotic resistance, is highly similar to that in the intergenic regions of the host genome. Our results show that the mutation rate varies around the chromosome, with the lowest mutation rate found near the origin of replication. Consistent with observations from other studies, we find that site-specific mutation rates are heavily influenced by the immediately flanking nucleotides, indicating that mutations are context dependent. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  18. Mutational analysis of the mycobacteriophage BPs promoter PR reveals context-dependent sequences for mycobacterial gene expression.

    Science.gov (United States)

    Oldfield, Lauren M; Hatfull, Graham F

    2014-10-01

    The PR promoter of mycobacteriophage BPs directs early lytic gene expression and is under the control of the BPs repressor, gp33. Reporter gene fusions showed that PR has modest activity in an extrachromosomal context but has activity that is barely detectable in an integrated context, even in the absence of its repressor. Mutational dissection of PR showed that it uses a canonical -10 hexamer recognized by SigA, and mutants with mutations to the sequence 5'-TATAMT had the greatest activities. It does not contain a 5'-TGN-extended -10 sequence, although mutants with mutations creating an extended -10 sequence had substantially increased promoter activity. Mutations in the -35 hexamer also influenced promoter activity but were strongly context dependent, and similar substitutions in the -35 hexamer differentially affected promoter activity, depending on the -10 and extended -10 motifs. This warrants caution in the construction of synthetic promoters or the bioinformatic prediction of promoter activity. Combinations of mutations throughout PR generated a calibrated series of promoters for expression of stably integrated recombinant genes in both Mycobacterium smegmatis and M. tuberculosis, with maximal promoter activity being more than 2-fold that of the strong hsp60 promoter. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  19. Context-dependent encoding of fear and extinction memories in a large-scale network model of the basal amygdala.

    Directory of Open Access Journals (Sweden)

    Ioannis Vlachos

    2011-03-01

    Full Text Available The basal nucleus of the amygdala (BA is involved in the formation of context-dependent conditioned fear and extinction memories. To understand the underlying neural mechanisms we developed a large-scale neuron network model of the BA, composed of excitatory and inhibitory leaky-integrate-and-fire neurons. Excitatory BA neurons received conditioned stimulus (CS-related input from the adjacent lateral nucleus (LA and contextual input from the hippocampus or medial prefrontal cortex (mPFC. We implemented a plasticity mechanism according to which CS and contextual synapses were potentiated if CS and contextual inputs temporally coincided on the afferents of the excitatory neurons. Our simulations revealed a differential recruitment of two distinct subpopulations of BA neurons during conditioning and extinction, mimicking the activation of experimentally observed cell populations. We propose that these two subgroups encode contextual specificity of fear and extinction memories, respectively. Mutual competition between them, mediated by feedback inhibition and driven by contextual inputs, regulates the activity in the central amygdala (CEA thereby controlling amygdala output and fear behavior. The model makes multiple testable predictions that may advance our understanding of fear and extinction memories.

  20. Context-dependent fluctuation of serotonin in the auditory midbrain: the influence of sex, reproductive state and experience

    Science.gov (United States)

    Hanson, Jessica L.; Hurley, Laura M.

    2014-01-01

    In the face of changing behavioral situations, plasticity of sensory systems can be a valuable mechanism to facilitate appropriate behavioral responses. In the auditory system, the neurotransmitter serotonin is an important messenger for context-dependent regulation because it is sensitive to both external events and internal state, and it modulates neural activity. In male mice, serotonin increases in the auditory midbrain region, the inferior colliculus (IC), in response to changes in behavioral context such as restriction stress and social contact. Female mice have not been measured in similar contexts, although the serotonergic system is sexually dimorphic in many ways. In the present study, we investigated the effects of sex, experience and estrous state on the fluctuation of serotonin in the IC across contexts, as well as potential relationships between behavior and serotonin. Contrary to our expectation, there were no sex differences in increases of serotonin in response to a restriction stimulus. Both sexes had larger increases in second exposures, suggesting experience plays a role in serotonergic release in the IC. In females, serotonin increased during both restriction and interactions with males; however, the increase was more rapid during restriction. There was no effect of female estrous phase on the serotonergic change for either context, but serotonin was related to behavioral activity in females interacting with males. These results show that changes in behavioral context induce increases in serotonin in the IC by a mechanism that appears to be uninfluenced by sex or estrous state, but may depend on experience and behavioral activity. PMID:24198252

  1. OTX2 exhibits cell-context-dependent effects on cellular and molecular properties of human embryonic neural precursors and medulloblastoma cells

    Directory of Open Access Journals (Sweden)

    Ravinder Kaur

    2015-10-01

    Full Text Available Medulloblastoma (MB is the most common malignant primary pediatric brain tumor and is currently divided into four subtypes based on different genomic alterations, gene expression profiles and response to treatment: WNT, Sonic Hedgehog (SHH, Group 3 and Group 4. This extensive heterogeneity has made it difficult to assess the functional relevance of genes to malignant progression. For example, expression of the transcription factor Orthodenticle homeobox2 (OTX2 is frequently dysregulated in multiple MB variants; however, its role may be subtype specific. We recently demonstrated that neural precursors derived from transformed human embryonic stem cells (trans-hENs, but not their normal counterparts (hENs, resemble Groups 3 and 4 MB in vitro and in vivo. Here, we tested the utility of this model system as a means of dissecting the role of OTX2 in MB using gain- and loss-of-function studies in hENs and trans-hENs, respectively. Parallel experiments with MB cells revealed that OTX2 exerts inhibitory effects on hEN and SHH MB cells by regulating growth, self-renewal and migration in vitro and tumor growth in vivo. This was accompanied by decreased expression of pluripotent genes, such as SOX2, and was supported by overexpression of SOX2 in OTX2+ SHH MB and hENs that resulted in significant rescue of self-renewal and cell migration. By contrast, OTX2 is oncogenic and promotes self-renewal of trans-hENs and Groups 3 and 4 MB independent of pluripotent gene expression. Our results demonstrate a novel role for OTX2 in self-renewal and migration of hENs and MB cells and reveal a cell-context-dependent link between OTX2 and pluripotent genes. Our study underscores the value of human embryonic stem cell derivatives as alternatives to cell lines and heterogeneous patient samples for investigating the contribution of key developmental regulators to MB progression.

  2. GNG Motifs Can Replace a GGG Stretch during G-Quadruplex Formation in a Context Dependent Manner.

    Science.gov (United States)

    Das, Kohal; Srivastava, Mrinal; Raghavan, Sathees C

    2016-01-01

    G-quadruplexes are one of the most commonly studied non-B DNA structures. Generally, these structures are formed using a minimum of 4, three guanine tracts, with connecting loops ranging from one to seven. Recent studies have reported deviation from this general convention. One such deviation is the involvement of bulges in the guanine tracts. In this study, guanines along with bulges, also referred to as GNG motifs have been extensively studied using recently reported HOX11 breakpoint fragile region I as a model template. By strategic mutagenesis approach we show that the contribution from continuous G-tracts may be dispensible during G-quadruplex formation when such motifs are flanked by GNGs. Importantly, the positioning and number of GNG/GNGNG can also influence the formation of G-quadruplexes. Further, we assessed three genomic regions from HIF1 alpha, VEGF and SHOX gene for G-quadruplex formation using GNG motifs. We show that HIF1 alpha sequence harbouring GNG motifs can fold into intramolecular G-quadruplex. In contrast, GNG motifs in mutant VEGF sequence could not participate in structure formation, suggesting that the usage of GNG is context dependent. Importantly, we show that when two continuous stretches of guanines are flanked by two independent GNG motifs in a naturally occurring sequence (SHOX), it can fold into an intramolecular G-quadruplex. Finally, we show the specific binding of G-quadruplex binding protein, Nucleolin and G-quadruplex antibody, BG4 to SHOX G-quadruplex. Overall, our study provides novel insights into the role of GNG motifs in G-quadruplex structure formation which may have both physiological and pathological implications.

  3. GNG Motifs Can Replace a GGG Stretch during G-Quadruplex Formation in a Context Dependent Manner.

    Directory of Open Access Journals (Sweden)

    Kohal Das

    Full Text Available G-quadruplexes are one of the most commonly studied non-B DNA structures. Generally, these structures are formed using a minimum of 4, three guanine tracts, with connecting loops ranging from one to seven. Recent studies have reported deviation from this general convention. One such deviation is the involvement of bulges in the guanine tracts. In this study, guanines along with bulges, also referred to as GNG motifs have been extensively studied using recently reported HOX11 breakpoint fragile region I as a model template. By strategic mutagenesis approach we show that the contribution from continuous G-tracts may be dispensible during G-quadruplex formation when such motifs are flanked by GNGs. Importantly, the positioning and number of GNG/GNGNG can also influence the formation of G-quadruplexes. Further, we assessed three genomic regions from HIF1 alpha, VEGF and SHOX gene for G-quadruplex formation using GNG motifs. We show that HIF1 alpha sequence harbouring GNG motifs can fold into intramolecular G-quadruplex. In contrast, GNG motifs in mutant VEGF sequence could not participate in structure formation, suggesting that the usage of GNG is context dependent. Importantly, we show that when two continuous stretches of guanines are flanked by two independent GNG motifs in a naturally occurring sequence (SHOX, it can fold into an intramolecular G-quadruplex. Finally, we show the specific binding of G-quadruplex binding protein, Nucleolin and G-quadruplex antibody, BG4 to SHOX G-quadruplex. Overall, our study provides novel insights into the role of GNG motifs in G-quadruplex structure formation which may have both physiological and pathological implications.

  4. Involvement of dopamine D1/D5 and D2 receptors in context-dependent extinction learning and memory reinstatement

    Directory of Open Access Journals (Sweden)

    Marion Agnes Emma Andre

    2016-01-01

    Full Text Available Dopamine contributes to the regulation of higher order information processing and executive control. It is important for memory consolidation processes, and for the adaptation of learned responses based on experience. In line with this, under aversive learning conditions, application of dopamine receptor antagonists prior to extinction result in enhanced memory reinstatement. Here, we investigated the contribution of the dopaminergic system to extinction and memory reinstatement (renewal of an appetitive spatial learning task in rodents. Rats were trained for 3 days in a T-maze (context ‘A’ to associate a goal arm with a food reward, despite low reward probability (acquisition phase. On day 4, extinction learning (unrewarded occurred, that was reinforced by a context change (‘B’. On day 5, re-exposure to the (unrewarded ‘A’-context took place (renewal of context ‘A’, followed by extinction of context ‘A’. In control animals, significant extinction occurred on day 4, that was followed by an initial memory reinstatement (renewal on day 5, that was, in turn, succeeded by extinction of renewal. Intracerebral treatment with a D1/D5-receptor antagonist prior to the extinction trials, elicited a potent enhancement of extinction in context ‘B’. By contrast, a D1/D5-agonist impaired renewal in context ’A’. Extinction in the ‘A’ context on day 5 was unaffected by the D1/D5-ligands. Treatment with a D2-receptor antagonist prior to extinction had no overall effect on extinction in context ‘B or renewal in context ‘A’, although extinction of the renewal effect was impaired on day 5, compared to controls.Taken together, these data suggest that dopamine acting on the D1/D5-receptor modulates both acquisition and consolidation of context-dependent extinction. By contrast, the D2-receptor may contribute to context-independent aspects of this kind of extinction learning.

  5. Context-dependent effects of a single administration of mirtazapine on the expression of methamphetamine-induced conditioned place preference

    Directory of Open Access Journals (Sweden)

    Robin eVoigt

    2012-01-01

    Full Text Available Re-exposure to cues repeatedly associated with methamphetamine (Meth can trigger Meth-seeking and relapse in the abstinent abuser. Weakening the conditioned Meth-associated memory during cue re-exposure may provide a means for relapse-reduction pharmacotherapy. Accordingly, we sought to determine if the atypical antidepressant mirtazapine disrupted the long-term maintenance of Meth-induced conditioned place preference (CPP when administered in conjunction with re-exposure to contextual conditioning cues, and if this effect was altered by Meth being present during cue re-exposure. First, we evaluated the effect of mirtazapine on the maintenance of Meth-induced CPP during re-exposure to either the saline- or Meth-paired chamber 12 days after conditioning. Meth conditioned rats subsequently administered mirtazapine expressed CPP independent of re-exposure to the saline- or Meth-paired chamber; but the magnitude of CPP was significantly less for mirtazapine-treated rats re-exposed to the Meth-paired chamber. Next, we evaluated the effect of mirtazapine on a ‘reinforced re-exposure’ to the Meth-paired context. Administration of mirtazapine vehicle and Meth, prior to re-exposure to the Meth-paired chamber did not disrupt the ability of rats to demonstrate CPP on day 20; however, rats administered mirtazapine and Meth prior to re-exposure to the Meth-paired chamber did not demonstrate CPP. These results indicate a context-dependent effect of mirtazapine, and that the ability of mirtazapine to disrupt the long-term maintenance of CPP is greatest when the atypical antidepressant is tested with a combination of Meth injection and contextual cues.

  6. The metabolic costs of sexual signalling in the chirping katydidPlangia graminea(Serville) (Orthoptera: Tettigoniidae) are context dependent: cumulative costs add up fast.

    Science.gov (United States)

    Doubell, Marcé; Grant, Paul B C; Esterhuizen, Nanike; Bazelet, Corinna S; Addison, Pia; Terblanche, John S

    2017-12-01

    Katydids produce acoustic signals via stridulation, which they use to attract conspecific females for mating. However, direct estimates of the metabolic costs of calling to date have produced diverse cost estimates and are limited to only a handful of insect species. Therefore, in this study, we investigated the metabolic cost of calling in an unstudied sub-Saharan katydid, Plangia graminea Using wild-caught animals, we measured katydid metabolic rate using standard flow-through respirometry while simultaneously recording the number of calls produced. Overall, the metabolic rate during calling in P. graminea males was 60% higher than the resting metabolic rate (0.443±0.056 versus 0.279±0.028 ml CO 2  h -1 g -1 ), although this was highly variable among individuals. Although individual call costs were relatively inexpensive (ranging from 0.02 to 5.4% increase in metabolic rate per call), the individuals with cheaper calls called more often and for longer than those with expensive calls, resulting in the former group having significantly greater cumulative costs over a standard amount of time (9.5 h). However, the metabolic costs of calling are context dependent because the amount of time spent calling greatly influenced these costs in our trials. A power law function described this relationship between cumulative cost ( y ) and percentage increase per call ( x ) ( y =130.21 x -1.068 , R 2 =0.858). The choice of metric employed for estimating energy costs (i.e. how costs are expressed) also affects the outcome and any interpretation of costs of sexual signalling. For example, the absolute, relative and cumulative metabolic costs of calling yielded strongly divergent estimates, and any fitness implications depend on the organism's energy budget and the potential trade-offs in allocation of resources that are made as a direct consequence of increased calling effort. © 2017. Published by The Company of Biologists Ltd.

  7. Ketamine-induced deficits in auditory and visual context-dependent processing in healthy volunteers: implications for models of cognitive deficits in schizophrenia.

    Science.gov (United States)

    Umbricht, D; Schmid, L; Koller, R; Vollenweider, F X; Hell, D; Javitt, D C

    2000-12-01

    In patients with schizophrenia, deficient generation of mismatch negativity (MMN)-an event-related potential (ERP) indexing auditory sensory ("echoic") memory-and a selective increase of "context dependent" ("BX") errors in the "A-X" version of the Continuous Performance Test (AX-CPT) indicate an impaired ability to form and use transient memory traces. Animal and human studies implicate deficient N-methyl-D-aspartate receptor (NMDAR) functioning in such abnormalities. In this study, effects of the NMDAR antagonists ketamine on MMN generation and AX-CPT performance were investigated in healthy volunteers to test the hypothesis that NMDARs are critically involved in human MMN generation, and to assess the nature of ketamine-induced deficits in AX-CPT performance. In a single-blind placebo-controlled study, 20 healthy volunteers underwent an infusion with subanesthetic doses of ketamine. The MMN-to-pitch and MMN-to-duration deviants were obtained while subjects performed an AX-CPT. Ketamine significantly decreased the peak amplitudes of the MMN-to-pitch and MMN-to-duration deviants by 27% and 21%, respectively. It induced performance deficits in the AX-CPT characterized by decreased hit rates and specific increases of errors (BX errors), reflecting a failure to form and use transient memory traces of task relevant information. The NMDARs are critically involved in human MMN generation. Deficient MMN in schizophrenia thus suggests deficits in NMDAR-related neurotransmission. N-methyl-D-aspartate receptor dysfunction may also contribute to the impairment of patients with schizophrenia in forming and using transient memory traces in more complex tasks, such as the AX-CPT. Thus, NMDAR-related dysfunction may underlie deficits in transient memory at different levels of information processing in schizophrenia. Arch Gen Psychiatry. 2000;57:1139-1147.

  8. Mechanisms of Matrix Metalloproteinase-Mediated p53 Regulation

    National Research Council Canada - National Science Library

    Fata, Jimmie E

    2006-01-01

    .... Several members of the TNF-ligand superfamily, which are associated with the promotion of a number of pathological processes, including inflammation and cancer are also capable of inducing membrane...

  9. Same habitat types but different use: evidence of context-dependent habitat selection in roe deer across populations.

    Science.gov (United States)

    William, Gaudry; Jean-Michel, Gaillard; Sonia, Saïd; Christophe, Bonenfant; Atle, Mysterud; Nicolas, Morellet; Maryline, Pellerin; Clément, Calenge

    2018-03-23

    With the surge of GPS-technology, many studies uncovered space use of mobile animals and shed light on the underlying behavioral mechanisms of habitat selection. Habitat selection and variation in either occurrence or strength of functional responses (i.e. how selection changes with availability) have given new insight into such mechanisms within populations in different ecosystems. However, linking variation in habitat selection to site-specific conditions in different populations facing contrasting environmental conditions but the same habitat type has not yet been investigated. We aimed to fill this knowledge gap by comparing within-home range habitat selection across 61 female roe deer (Capreolus capreolus) during the most critical life history stage in three study areas showing the same habitat types but with different environmental conditions. Female roe deer markedly differed in habitat selection within their home range, both within and among populations. Females facing poor environmental conditions clearly displayed a functional response, whereas females facing rich environmental conditions did not show any functional response. These results demonstrate how the use of a given habitat relative to its availability strongly varies in response to environmental conditions. Our findings highlight that the same habitat composition can lead to very different habitat selection processes across contrasted environments.

  10. Context-dependent consequences of Marenzelleria spp. (Spionidae: Polychaeta invasion for nutrient cycling in the Northern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Alexey Maximov

    2015-10-01

    Full Text Available Marenzelleria spp. are among the most successful non-native benthic species in the Baltic Sea. These burrowing polychaetes dig deeper than most native Baltic species, performing previously lacking ecosystem functions. We examine evidence from experiments, field sampling and modelling that the introduction of Marenzelleria spp. affects nutrient cycling and biogeochemical processes at the sediment–water interface. Over longer time scales, bioirrigation by Marenzelleria spp. has the potential to increase phosphorus retention in bottom deposits because of deeper oxygen penetration into sediments and formation of a deeper oxidized layer. In contrast, nitrogen fluxes from the sediment increase. As a consequence of a decline of the phosphate concentration and/or rising nitrogen/phosphorus ratio, some Northern Baltic ecosystems may experience improvement of the environment because of mitigation of eutrophication and harmful cyanobacteria blooms. Although it is difficult to unambiguously estimate the ecosystem-level consequences of invasion, in many cases it could be considered as positive due to increased structural and functional diversity. The long-term interactions with the native fauna still remain unknown, however, and in this paper we highlight the major knowledge gaps.

  11. Context-dependent wiring of Sox2 regulatory networks for self-renewal of embryonic and trophoblast stem cells.

    Science.gov (United States)

    Adachi, Kenjiro; Nikaido, Itoshi; Ohta, Hiroshi; Ohtsuka, Satoshi; Ura, Hiroki; Kadota, Mitsutaka; Wakayama, Teruhiko; Ueda, Hiroki R; Niwa, Hitoshi

    2013-11-07

    Sox2 is a transcription factor required for the maintenance of pluripotency. It also plays an essential role in different types of multipotent stem cells, raising the possibility that Sox2 governs the common stemness phenotype. Here we show that Sox2 is a critical downstream target of fibroblast growth factor (FGF) signaling, which mediates self-renewal of trophoblast stem cells (TSCs). Sustained expression of Sox2 together with Esrrb or Tfap2c can replace FGF dependency. By comparing genome-wide binding sites of Sox2 in embryonic stem cells (ESCs) and TSCs combined with inducible knockout systems, we found that, despite the common role in safeguarding the stem cell state, Sox2 regulates distinct sets of genes with unique functions in these two different yet developmentally related types of stem cells. Our findings provide insights into the functional versatility of transcription factors during embryogenesis, during which they can be recursively utilized in a variable manner within discrete network structures. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Social anxiety and romantic relationships: the costs and benefits of negative emotion expression are context-dependent.

    Science.gov (United States)

    Kashdan, Todd B; Volkmann, Jeffrey R; Breen, William E; Han, Susan

    2007-01-01

    In general, expressing emotions is beneficial and withholding emotions has personal and social costs. Yet, to serve social functions there are situations when emotions are withheld strategically. We examined whether social anxiety influenced when and how emotion expressiveness influences interpersonal closeness in existing romantic relationships. For people with greater social anxiety, withholding the expression of negative emotions was proposed to preserve romantic relationships and their benefits. We examined whether social anxiety and emotion expressiveness interacted to predict prospective changes in romantic relationship closeness over a 12-week period. For people with less social anxiety, relationship closeness was enhanced over time when negative emotions were openly expressed whereas relationship deterioration was found for those more likely to withhold emotions. The reverse pattern was found for people with greater social anxiety such that relationship closeness was enhanced over time for those more likely to withhold negative emotions. Related social anxiety findings were found for discrepancies between desired and actual feelings of closeness over time. Findings were not attributable to depressive symptoms. These results suggest that the costs and benefits of emotion expression are influenced by a person's degree of social anxiety.

  13. The relationship between the neural computations for speech and music perception is context-dependent: an activation likelihood estimate study

    Directory of Open Access Journals (Sweden)

    Arianna eLaCroix

    2015-08-01

    Full Text Available The relationship between the neurobiology of speech and music has been investigated for more than a century. There remains no widespread agreement regarding how (or to what extent music perception utilizes the neural circuitry that is engaged in speech processing, particularly at the cortical level. Prominent models such as Patel’s Shared Syntactic Integration Resource Hypothesis (SSIRH and Koelsch’s neurocognitive model of music perception suggest a high degree of overlap, particularly in the frontal lobe, but also perhaps more distinct representations in the temporal lobe with hemispheric asymmetries. The present meta-analysis study used activation likelihood estimate analyses to identify the brain regions consistently activated for music as compared to speech across the functional neuroimaging (fMRI and PET literature. Eighty music and 91 speech neuroimaging studies of healthy adult control subjects were analyzed. Peak activations reported in the music and speech studies were divided into four paradigm categories: passive listening, discrimination tasks, error/anomaly detection tasks and memory-related tasks. We then compared activation likelihood estimates within each category for music versus speech, and each music condition with passive listening. We found that listening to music and to speech preferentially activate distinct temporo-parietal bilateral cortical networks. We also found music and speech to have shared resources in the left pars opercularis but speech-specific resources in the left pars triangularis. The extent to which music recruited speech-activated frontal resources was modulated by task. While there are certainly limitations to meta-analysis techniques particularly regarding sensitivity, this work suggests that the extent of shared resources between speech and music may be task-dependent and highlights the need to consider how task effects may be affecting conclusions regarding the neurobiology of speech and music.

  14. Context-dependent neural activation: internally and externally guided rhythmic lower limb movement in individuals with and without neurodegenerative disease

    Directory of Open Access Journals (Sweden)

    Madeleine Eve Hackney

    2015-12-01

    Full Text Available Parkinson’s Disease (PD is a neurodegenerative disorder that has received considerable attention in allopathic medicine over the past decades. However, it is clear that, to date, pharmacological and surgical interventions do not fully address symptoms of PD and patients’ quality of life. As both an alternative therapy and as an adjuvant to conventional approaches, several types of rhythmic movement (e.g., movement strategies, dance, tandem biking, tai chi have shown improvements to motor symptoms, lower limb control and postural stability in people with PD (Amano, Nocera, Vallabhajosula, Juncos, Gregor, Waddell et al., 2013; Earhart, 2009; M. E. Hackney & Earhart, 2008; Kadivar, Corcos, Foto, & Hondzinski, 2011; Morris, Iansek, & Kirkwood, 2009; Ridgel, Vitek, & Alberts, 2009. However, while these programs are increasing in number, still little is known about the neural mechanisms underlying motor improvements attained with such interventions. Studying limb motor control under task specific contexts can help determine the mechanisms of rehabilitation effectiveness. Both internally guided (IG and externally guided (EG movement strategies have evidence to support their use in rehabilitative programs. However, there appears to be a degree of differentiation in the neural substrates involved in IG versus EG designs. Because of the potential task specific benefits of rhythmic training within a rehabilitative context, this report will consider the use of IG and EG movement strategies, and observations produced by functional magnetic resonance imaging (fMRI and other imaging techniques. This review will present findings from lower limb imaging studies, under IG and EG conditions for populations with and without movement disorders. We will discuss how these studies might inform movement disorders rehabilitation (in the form of rhythmic, music-based movement training and highlight research gaps. We believe better understanding of lower limb neural

  15. Relative Contributions of the Dorsal vs. Ventral Speech Streams to Speech Perception are Context Dependent: a lesion study

    Directory of Open Access Journals (Sweden)

    Corianne Rogalsky

    2014-04-01

    Full Text Available The neural basis of speech perception has been debated for over a century. While it is generally agreed that the superior temporal lobes are critical for the perceptual analysis of speech, a major current topic is whether the motor system contributes to speech perception, with several conflicting findings attested. In a dorsal-ventral speech stream framework (Hickok & Poeppel 2007, this debate is essentially about the roles of the dorsal versus ventral speech processing streams. A major roadblock in characterizing the neuroanatomy of speech perception is task-specific effects. For example, much of the evidence for dorsal stream involvement comes from syllable discrimination type tasks, which have been found to behaviorally doubly dissociate from auditory comprehension tasks (Baker et al. 1981. Discrimination task deficits could be a result of difficulty perceiving the sounds themselves, which is the typical assumption, or it could be a result of failures in temporary maintenance of the sensory traces, or the comparison and/or the decision process. Similar complications arise in perceiving sentences: the extent of inferior frontal (i.e. dorsal stream activation during listening to sentences increases as a function of increased task demands (Love et al. 2006. Another complication is the stimulus: much evidence for dorsal stream involvement uses speech samples lacking semantic context (CVs, non-words. The present study addresses these issues in a large-scale lesion-symptom mapping study. 158 patients with focal cerebral lesions from the Mutli-site Aphasia Research Consortium underwent a structural MRI or CT scan, as well as an extensive psycholinguistic battery. Voxel-based lesion symptom mapping was used to compare the neuroanatomy involved in the following speech perception tasks with varying phonological, semantic, and task loads: (i two discrimination tasks of syllables (non-words and words, respectively, (ii two auditory comprehension tasks

  16. Context-dependent responses to novelty in Rainbow trout (Oncorhynchus mykiss), selected for high and low post-stress cortisol responsiveness

    DEFF Research Database (Denmark)

    Basic, D.; Winberg, S.; Schjolden, J.

    2012-01-01

    in challenging situations than the LR counterpart. The present study addressed whether such variation in behavioral flexibility traits was evident in different experimental settings using these selection lines. The fish were subjected to three sets of challenges (novel object test, resident–intruder test...... and confinement stressor test), all which were repeated a week later. Introducing a novel object evoked a divergent behavioral response in association with feeding: fish from the LR line displayed consistently suppressed feed intake while the HR fish remained unaffected. This observation was found...... to be repeatable along with attack latency and movement activity from the resident–intruder and confinement stressor tests. These results indicate that the behavioral responses in this animal model are context-dependent and shed new light on the expression of behavioral flexibility....

  17. HIV-1 envelope glycoprotein resistance to monoclonal antibody 2G12 is subject-specific and context-dependent in macaques and humans.

    Directory of Open Access Journals (Sweden)

    Delphine C Malherbe

    Full Text Available HIV-1 Envelope (Env protein is the sole target of neutralizing antibodies (NAbs that arise during infection to neutralize autologous variants. Under this immune pressure, HIV escape variants are continuously selected and over the course of infection Env becomes more neutralization resistant. Many common alterations are known to affect sensitivity to NAbs, including residues encoding potential N-linked glycosylation sites (PNGS. Knowledge of Env motifs associated with neutralization resistance is valuable for the design of an effective Env-based vaccine so we characterized Envs isolated longitudinally from a SHIV(SF162P4 infected macaque for sensitivity to neutralizing monoclonal antibodies (MAbs B12, 2G12, 4E10 and 2F5. The early Env, isolated from plasma at day 56 after infection, was the most sensitive and the late Env, from day 670, was the most resistant to MAbs. We identified four PNGS in these Envs that accumulated over time at positions 130, 139, 160 and 397. We determined that removal of these PNGS significantly increased neutralization sensitivity to 2G12, and conversely, we identified mutations by in silico analyses that contributed resistance to 2G12 neutralization. In order to expand our understanding of these PNGS, we analyzed Envs from clade B HIV-infected human subjects and identified additional glycan and amino acid changes that could affect neutralization by 2G12 in a context-dependent manner. Taken together, these in vitro and in silico analyses of clade B Envs revealed that 2G12 resistance is achieved by previously unrecognized PNGS substitutions in a context-dependent manner and by subject-specific pathways.

  18. Context dependence of risk effects

    NARCIS (Netherlands)

    Kuijper, D.P.J.; Bubnicki, J.W.; Churski, Marcin; Mols, Bjorn; Hooft, Van Pim

    2015-01-01

    Large mammalian carnivores create areas perceived as having high and low risk by their ungulate prey. Human activities can indirectly shape this landscape of fear by altering behavior and spatial distribution of carnivores. We studied how red deer perceive the landscape of fear in an old-growth

  19. Context dependent DNA evolutionary models

    DEFF Research Database (Denmark)

    Jensen, Jens Ledet

    This paper is about stochastic models for the evolution of DNA. For a set of aligned DNA sequences, connected in a phylogenetic tree, the models should be able to explain - in probabilistic terms - the differences seen in the sequences. From the estimates of the parameters in the model one can...

  20. Context dependent reversion of tumor phenotype by connexin-43 expression in MDA-MB231 cells and MCF-7 cells: Role of β-catenin/connexin43 association

    Energy Technology Data Exchange (ETDEWEB)

    Talhouk, Rabih S., E-mail: rtalhouk@aub.edu.lb [Department of Biology, Faculty of Arts and Sciences, American University of Beirut, P.O. Box 11-0236, Beirut (Lebanon); Fares, Mohamed-Bilal; Rahme, Gilbert J.; Hariri, Hanaa H.; Rayess, Tina; Dbouk, Hashem A.; Bazzoun, Dana; Al-Labban, Dania [Department of Biology, Faculty of Arts and Sciences, American University of Beirut, P.O. Box 11-0236, Beirut (Lebanon); El-Sabban, Marwan E., E-mail: me00@aub.edu.lb [Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut, P.O. Box 11-0236, Beirut (Lebanon)

    2013-12-10

    Connexins (Cx), gap junction (GJ) proteins, are regarded as tumor suppressors, and Cx43 expression is often down regulated in breast tumors. We assessed the effect of Cx43 over-expression in 2D and 3D cultures of two breast adenocarcinoma cell lines: MCF-7 and MDA-MB-231. While Cx43 over-expression decreased proliferation of 2D and 3D cultures of MCF-7 by 56% and 80% respectively, MDA-MB-231 growth was not altered in 2D cultures, but exhibited 35% reduction in 3D cultures. C-terminus truncated Cx43 did not alter proliferation. Untransfected MCF-7 cells formed spherical aggregates in 3D cultures, and MDA-MB-231 cells formed stellar aggregates. However, MCF-7 cells over-expressing Cx43 formed smaller sized clusters and Cx43 expressing MDA-MB-231 cells lost their stellar morphology. Extravasation ability of both MCF-7 and MDA-MB-231 cells was reduced by 60% and 30% respectively. On the other hand, silencing Cx43 in MCF10A cells, nonneoplastic human mammary cell line, increased proliferation in both 2D and 3D cultures, and disrupted acinar morphology. Although Cx43 over-expression did not affect total levels of β-catenin, α-catenin and ZO-2, it decreased nuclear levels of β-catenin in 2D and 3D cultures of MCF-7 cells, and in 3D cultures of MDA-MB-231 cells. Cx43 associated at the membrane with α-catenin, β-catenin and ZO-2 in 2D and 3D cultures of MCF-7 cells, and only in 3D conditions in MDA-MB-231 cells. This study suggests that Cx43 exerts tumor suppressive effects in a context-dependent manner where GJ assembly with α-catenin, β-catenin and ZO-2 may be implicated in reducing growth rate, invasiveness, and, malignant phenotype of 2D and 3D cultures of MCF-7 cells, and 3D cultures of MDA-MB-231 cells, by sequestering β-catenin away from nucleus. - Highlights: • Cx43 over-expressing MCF-7 and MDA-MB-231 were grown in 2D and 3D cultures. • Proliferation and growth morphology were affected in a context dependent manner. • Extravasation ability of both MCF

  1. TGF-β signal transduction spreading to a wider field: a broad variety of mechanisms for context-dependent effects of TGF-β.

    Science.gov (United States)

    Ikushima, Hiroaki; Miyazono, Kohei

    2012-01-01

    Transforming growth factor (TGF)-β signaling is involved in almost all major cell behaviors under physiological and pathological conditions, and its regulatory system has therefore been vigorously investigated. The fundamental elements in TGF-β signaling are TGF-β ligands, their receptors, and intracellular Smad effectors. The TGF-β ligand induces the receptors directly to phosphorylate and activate Smad proteins, which then form transcriptional complexes to control target genes. One of the classical questions in the field of research on TGF-β signaling is how this cytokine induces multiple cell responses depending on cell type and cellular context. Possible answers to this question include cross-interaction with other signaling pathways, different repertoires of Smad-binding transcription factors, and genetic alterations, especially in cancer cells. In addition to these genetic paradigms, recent work has extended TGF-β research into new fields, including epigenetic regulation and non-coding RNAs. In this review, we first describe the basic machinery of TGF-β signaling and discuss several factors that comprise TGF-β signaling networks. We then address mechanisms by which TGF-β induces several responses in a cell-context-dependent fashion. In addition to classical frames, the interaction of TGF-β signaling with epigenetics and microRNA is discussed.

  2. Genomic response to Wnt signalling is highly context-dependent - Evidence from DNA microarray and chromatin immunoprecipitation screens of Wnt/TCF targets

    International Nuclear Information System (INIS)

    Railo, Antti; Pajunen, Antti; Itaeranta, Petri; Naillat, Florence; Vuoristo, Jussi; Kilpelaeinen, Pekka; Vainio, Seppo

    2009-01-01

    Wnt proteins are important regulators of embryonic development, and dysregulated Wnt signalling is involved in the oncogenesis of several human cancers. Our knowledge of the downstream target genes is limited, however. We used a chromatin immunoprecipitation-based assay to isolate and characterize the actual gene segments through which Wnt-activatable transcription factors, TCFs, regulate transcription and an Affymetrix microarray analysis to study the global transcriptional response to the Wnt3a ligand. The anti-β-catenin immunoprecipitation of DNA-protein complexes from mouse NIH3T3 fibroblasts expressing a fusion protein of β-catenin and TCF7 resulted in the identification of 92 genes as putative TCF targets. GeneChip assays of gene expression performed on NIH3T3 cells and the rat pheochromocytoma cell line PC12 revealed 355 genes in NIH3T3 and 129 genes in the PC12 cells with marked changes in expression after Wnt3a stimulus. Only 2 Wnt-regulated genes were shared by both cell lines. Surprisingly, Disabled-2 was the only gene identified by the chromatin immunoprecipitation approach that displayed a marked change in expression in the GeneChip assay. Taken together, our approaches give an insight into the complex context-dependent nature of Wnt pathway transcriptional responses and identify Disabled-2 as a potential new direct target for Wnt signalling.

  3. The priming of priming: Evidence that the N400 reflects context-dependent post-retrieval word integration in working memory.

    Science.gov (United States)

    Steinhauer, Karsten; Royle, Phaedra; Drury, John E; Fromont, Lauren A

    2017-06-09

    Which cognitive processes are reflected by the N400 in ERPs is still controversial. Various recent articles (Lau et al., 2008; Brouwer et al., 2012) have revived the idea that only lexical pre-activation processes (such as automatic spreading activation, ASA) are strongly supported, while post-lexical integrative processes are not. Challenging this view, the present ERP study replicates a behavioral study by McKoon and Ratcliff (1995) who demonstrated that a prime-target pair such as finger - hand shows stronger priming when a majority of other pairs in the list share the analogous semantic relationship (here: part-whole), even at short stimulus onset asynchronies (250ms). We created lists with four different types of semantic relationship (synonyms, part-whole, category-member, and opposites) and compared priming for pairs in a consistent list with those in an inconsistent list as well as unrelated items. Highly significant N400 reductions were found for both relatedness priming (unrelated vs. inconsistent) and relational priming (inconsistent vs. consistent). These data are taken as strong evidence that N400 priming effects are not exclusively carried by ASA-like mechanisms during lexical retrieval but also include post-lexical integration in working memory. We link the present findings to a neurocomputational model for relational reasoning (Knowlton et al., 2012) and to recent discussions of context-dependent conceptual activations (Yee and Thompson-Schill, 2016). Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Characterisation of the Context-Dependence of the Gene Concept in Research Articles. Possible Consequences for Teaching Concepts with Multiple Meanings

    Science.gov (United States)

    Flodin, Veronica S.

    2017-03-01

    The purpose of this study is to interpret and qualitatively characterise the content in some research articles and evaluate cases of possible difference in meanings of the gene concept used. Using a reformulation of Hirst's criteria of forms of knowledge, articles from five different sub-disciplines in biology (transmission genetic, molecular biology, genomics, developmental biology and population genetics) were characterised according to knowledge project, methods used and conceptual contexts. Depending on knowledge project, the gene may be used as a location of recombination, a target of regulatory proteins, a carrier of regulatory sequences, a cause in organ formation or a basis for a genetic map. Methods used range from catching wild birds and dissecting beetle larvae to growing yeast cells in 94 small wells as well as mapping of recombinants, doing statistical calculations, immunoblotting analysis of protein levels, analysis of gene expression with PCR, immunostaining of embryos and automated constructions of multi-locus linkage maps. The succeeding conceptual contexts focused around concepts as meiosis and chromosome, DNA and regulation, cell fitness and production, development and organ formation, conservation and evolution. These contextual differences lead to certain content leaps in relation to different conceptual schemes. The analysis of the various uses of the gene concept shows how differences in methodologies and questions entail a concept that escapes single definitions and "drift around" in meanings. These findings make it important to ask how science might use concepts as tools of specific inquiries and to discuss possible consequences for biology education.

  5. Context-dependent expression of the foraging gene in field colonies of ants: the interacting roles of age, environment and task.

    Science.gov (United States)

    Ingram, Krista K; Gordon, Deborah M; Friedman, Daniel A; Greene, Michael; Kahler, John; Peteru, Swetha

    2016-08-31

    Task allocation among social insect workers is an ideal framework for studying the molecular mechanisms underlying behavioural plasticity because workers of similar genotype adopt different behavioural phenotypes. Elegant laboratory studies have pioneered this effort, but field studies involving the genetic regulation of task allocation are rare. Here, we investigate the expression of the foraging gene in harvester ant workers from five age- and task-related groups in a natural population, and we experimentally test how exposure to light affects foraging expression in brood workers and foragers. Results from our field study show that the regulation of the foraging gene in harvester ants occurs at two time scales: levels of foraging mRNA are associated with ontogenetic changes over weeks in worker age, location and task, and there are significant daily oscillations in foraging expression in foragers. The temporal dissection of foraging expression reveals that gene expression changes in foragers occur across a scale of hours and the level of expression is predicted by activity rhythms: foragers have high levels of foraging mRNA during daylight hours when they are most active outside the nests. In the experimental study, we find complex interactions in foraging expression between task behaviour and light exposure. Oscillations occur in foragers following experimental exposure to 13 L : 11 D (LD) conditions, but not in brood workers under similar conditions. No significant differences were seen in foraging expression over time in either task in 24 h dark (DD) conditions. Interestingly, the expression of foraging in both undisturbed field and experimentally treated foragers is also significantly correlated with the expression of the circadian clock gene, cycle Our results provide evidence that the regulation of this gene is context-dependent and associated with both ontogenetic and daily behavioural plasticity in field colonies of harvester ants. Our results underscore

  6. Sex differences in conditioned stimulus discrimination during context-dependent fear learning and its retrieval in humans: the role of biological sex, contraceptives and menstrual cycle phases.

    Science.gov (United States)

    Lonsdorf, Tina B; Haaker, Jan; Schümann, Dirk; Sommer, Tobias; Bayer, Janine; Brassen, Stefanie; Bunzeck, Nico; Gamer, Matthias; Kalisch, Raffael

    2015-11-01

    Anxiety disorders are more prevalent in women than in men. Despite this sexual dimorphism, most experimental studies are conducted in male participants and studies focusing on sex differences are sparse. In addition, the role of hormonal contraceptives and menstrual cycle phase in fear conditioning and extinction processes remain largely unknown. We investigated sex differences in context-dependent fear acquisition and extinction (day 1) and their retrieval/expression (day 2). Skin conductance responses (SCRs), fear and unconditioned stimulus expectancy ratings were obtained. We included 377 individuals (261 women) in our study. Robust sex differences were observed in all dependent measures. Women generally displayed higher subjective ratings but smaller SCRs than men and showed reduced excitatory/inhibitory conditioned stimulus (CS+/CS-) discrimination in all dependent measures. Furthermore, women using hormonal contraceptives showed reduced SCR CS discrimination on day 2 than men and free-cycling women, while menstrual cycle phase had no effect. Possible limitations include the simultaneous testing of up to 4 participants in cubicles, which might have introduced a social component, and not assessing postexperimental contingency awareness. The response pattern in women shows striking similarity to previously reported sex differences in patients with anxiety. Our results suggest that pronounced deficits in associative discrimination learning and subjective expression of safety information (CS- responses) might underlie higher prevalence and higher symptom rates seen in women with anxiety disorders. The data call for consideration of biological sex and hormonal contraceptive use in future studies and may suggest that targeting inhibitory learning during therapy might aid precision medicine.

  7. Pro- and anti-apoptotic effects of p53 in cisplatin-treated human testicular cancer are cell context-dependent

    NARCIS (Netherlands)

    di Pietro, Alessandra; Koster, Roelof; Boersma-van Eck, Wytske; Dam, Wendy A.; Mulder, Nanno H.; Gietema, Jourik A.; de Vries, Elisabeth G. E.; de Jong, Steven

    2012-01-01

    In murine testicular cancer (TC) cells wild-type p53 contributes to sensitivity to DNA-damaging drugs in a dose-dependent way. In human TC, however, the role of wild-type p53 functionality in chemotherapeutic response remains elusive. We analyzed functionality of wild-type p53 in cisplatin

  8. Context-dependent protein folding of a virulence peptide in the bacterial and host environments: structure of an SycH–YopH chaperone–effector complex

    International Nuclear Information System (INIS)

    Vujanac, Milos; Stebbins, C. Erec

    2013-01-01

    The structure of a SycH–YopH chaperone–effector complex from Yersinia reveals the bacterial state of a protein that adopts different folds in the host and pathogen environments. Yersinia pestis injects numerous bacterial proteins into host cells through an organic nanomachine called the type 3 secretion system. One such substrate is the tyrosine phosphatase YopH, which requires an interaction with a cognate chaperone in order to be effectively injected. Here, the first crystal structure of a SycH–YopH complex is reported, determined to 1.9 Å resolution. The structure reveals the presence of (i) a nonglobular polypeptide in YopH, (ii) a so-called β-motif in YopH and (iii) a conserved hydrophobic patch in SycH that recognizes the β-motif. Biochemical studies establish that the β-motif is critical to the stability of this complex. Finally, since previous work has shown that the N-terminal portion of YopH adopts a globular fold that is functional in the host cell, aspects of how this polypeptide adopts radically different folds in the host and in the bacterial environments are analysed

  9. Context-dependent lexical ambiguity resolution: MEG evidence for the time-course of activity in left inferior frontal gyrus and posterior middle temporal gyrus.

    Science.gov (United States)

    Mollo, Giovanna; Jefferies, Elizabeth; Cornelissen, Piers; Gennari, Silvia P

    An MEG study investigated the role of context in semantic interpretation by examining the comprehension of ambiguous words in contexts leading to different interpretations. We compared high-ambiguity words in minimally different contexts (to bowl, the bowl) to low-ambiguity counterparts (the tray, to flog). Whole brain beamforming revealed the engagement of left inferior frontal gyrus (LIFG) and posterior middle temporal gyrus (LPMTG). Points of interest analyses showed that both these sites showed a stronger response to verb-contexts by 200 ms post-stimulus and displayed overlapping ambiguity effects that were sustained from 300 ms onwards. The effect of context was stronger for high-ambiguity words than for low-ambiguity words at several different time points, including within the first 100 ms post-stimulus. Unlike LIFG, LPMTG also showed stronger responses to verb than noun contexts in low-ambiguity trials. We argue that different functional roles previously attributed to LIFG and LPMTG are in fact played out at different periods during processing. Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.

  10. From repulsion to attraction: species- and spatial context-dependent threat sensitive response of the spider mite Tetranychus urticae to predatory mite cues

    Science.gov (United States)

    Fernández Ferrari, M. Celeste; Schausberger, Peter

    2013-06-01

    Prey perceiving predation risk commonly change their behavior to avoid predation. However, antipredator strategies are costly. Therefore, according to the threat-sensitive predator avoidance hypothesis, prey should match the intensity of their antipredator behaviors to the degree of threat, which may depend on the predator species and the spatial context. We assessed threat sensitivity of the two-spotted spider mite, Tetranychus urticae, to the cues of three predatory mites, Phytoseiulus persimilis, Neoseiulus californicus, and Amblyseius andersoni, posing different degrees of risk in two spatial contexts. We first conducted a no-choice test measuring oviposition and activity of T. urticae exposed to chemical traces of predators or traces plus predator eggs. Then, we tested the site preference of T. urticae in choice tests, using artificial cages and leaves. In the no-choice test, T. urticae deposited their first egg later in the presence of cues of P. persimilis than of the other two predators and cue absence, indicating interspecific threat-sensitivity. T. urticae laid also fewer eggs in the presence of cues of P. persimilis and A. andersoni than of N. californicus and cue absence. In the artificial cage test, the spider mites preferred the site with predator traces, whereas in the leaf test, they preferentially resided on leaves without traces. We argue that in a nonplant environment, chemical predator traces do not indicate a risk for T. urticae, and instead, these traces function as indirect habitat cues. The spider mites were attracted to these cues because they associated them with the existence of a nearby host plant.

  11. Context-dependent social evaluation in 4.5-month-old human infants: The role of domain-general versus domain-specific processes in the development of social evaluation

    Directory of Open Access Journals (Sweden)

    J Kiley eHamlin

    2014-06-01

    Full Text Available The ability to distinguish friends from foes allows humans to engage in mutually beneficial cooperative acts while avoiding the costs associated with cooperating with the wrong individuals. One way to do so effectively is to observe how unknown individuals behave toward third parties, and to selectively cooperate with those who help others while avoiding those who harm others. Recent research suggests that a preference for prosocial over antisocial individuals emerges by the time that infants are 3 months of age, and by 8 months, but not before, infants evaluate others’ actions in context: they prefer those who harm, rather than help, individuals who have previously harmed others. Currently there are at least two reasons for younger infants’ failure to show context-dependent social evaluations. First, this failure may reflect fundamental change in infants’ social evaluation system over the first year of life, in which infants first prefer helpers in any situation and only later evaluate prosocial and antisocial actors in context. On the other hand, it is possible that this developmental change actually reflects domain-general limitations of younger infants, such as limited memory and processing capacities. To distinguish between these possibilities, 4.5-month-olds in the current studies were habituated, rather than familiarized as in previous work, to one individual helping and another harming a third party, greatly increasing infants’ exposure to the characters’ actions. Following habituation, 4.5-month-olds displayed context-dependent social preferences, selectively reaching for helpers of prosocial and hinderers of antisocial others. Such results suggest that younger infants’ failure to display global social evaluation in previous work reflected domain-general rather than domain-specific limitations.

  12. A Context Dependent Automatic Target Recognition System

    Science.gov (United States)

    Kim, J. H.; Payton, D. W.; Olin, K. E.; Tseng, D. Y.

    1984-06-01

    This paper describes a new approach to automatic target recognizer (ATR) development utilizing artificial intelligent techniques. The ATR system exploits contextual information in its detection and classification processes to provide a high degree of robustness and adaptability. In the system, knowledge about domain objects and their contextual relationships is encoded in frames, separating it from low level image processing algorithms. This knowledge-based system demonstrates an improvement over the conventional statistical approach through the exploitation of diverse forms of knowledge in its decision-making process.

  13. Context Dependent Analysis of BioAmbients

    DEFF Research Database (Denmark)

    Pilegaard, Henrik; Nielson, Flemming; Nielson, Hanne Riis

    2006-01-01

    BioAmbients is a derivative of mobile ambients that has shown promise of describing interesting features of the behaviour of biological systems. The technical contribution of this paper is to extend the Flow Logic approach to static analysis with a couple of new techniques in order to give precise...... information about the behaviour of systems written in BioAmbients. Applying the development to a simple model of a cell releasing nutrients from food compunds we illustrate how the proposed analysis does indeed improve on previous efforts....

  14. Context-dependent hierarchies in pigeons.

    Science.gov (United States)

    Nagy, Máté; Vásárhelyi, Gábor; Pettit, Benjamin; Roberts-Mariani, Isabella; Vicsek, Tamás; Biro, Dora

    2013-08-06

    Hierarchical organization is widespread in the societies of humans and other animals, both in social structure and in decision-making contexts. In the case of collective motion, the majority of case studies report that dominant individuals lead group movements, in agreement with the common conflation of the terms "dominance" and "leadership." From a theoretical perspective, if social relationships influence interactions during collective motion, then social structure could also affect leadership in large, swarm-like groups, such as fish shoals and bird flocks. Here we use computer-vision-based methods and miniature GPS tracking to study, respectively, social dominance and in-flight leader-follower relations in pigeons. In both types of behavior we find hierarchically structured networks of directed interactions. However, instead of being conflated, dominance and leadership hierarchies are completely independent of each other. Although dominance is an important aspect of variation among pigeons, correlated with aggression and access to food, our results imply that the stable leadership hierarchies in the air must be based on a different set of individual competences. In addition to confirming the existence of independent and context-specific hierarchies in pigeons, we succeed in setting out a robust, scalable method for the automated analysis of dominance relationships, and thus of social structure, applicable to many species. Our results, as well as our methods, will help to incorporate the broader context of animal social organization into the study of collective behavior.

  15. Reinstatement in Honeybees Is Context-Dependent

    Science.gov (United States)

    Plath, Jenny Aino; Felsenberg, Johannes; Eisenhardt, Dorothea

    2012-01-01

    During extinction animals experience that the previously learned association between a conditioned stimulus (CS) and an unconditioned stimulus (US) no longer holds true. Accordingly, the conditioned response (CR) to the CS decreases. This decrease of the CR can be reversed by presentation of the US alone following extinction, a phenomenon termed…

  16. Deep belief networks learn context dependent behavior.

    Directory of Open Access Journals (Sweden)

    Florian Raudies

    Full Text Available With the goal of understanding behavioral mechanisms of generalization, we analyzed the ability of neural networks to generalize across context. We modeled a behavioral task where the correct responses to a set of specific sensory stimuli varied systematically across different contexts. The correct response depended on the stimulus (A,B,C,D and context quadrant (1,2,3,4. The possible 16 stimulus-context combinations were associated with one of two responses (X,Y, one of which was correct for half of the combinations. The correct responses varied symmetrically across contexts. This allowed responses to previously unseen stimuli (probe stimuli to be generalized from stimuli that had been presented previously. By testing the simulation on two or more stimuli that the network had never seen in a particular context, we could test whether the correct response on the novel stimuli could be generated based on knowledge of the correct responses in other contexts. We tested this generalization capability with a Deep Belief Network (DBN, Multi-Layer Perceptron (MLP network, and the combination of a DBN with a linear perceptron (LP. Overall, the combination of the DBN and LP had the highest success rate for generalization.

  17. Deep belief networks learn context dependent behavior.

    Science.gov (United States)

    Raudies, Florian; Zilli, Eric A; Hasselmo, Michael E

    2014-01-01

    With the goal of understanding behavioral mechanisms of generalization, we analyzed the ability of neural networks to generalize across context. We modeled a behavioral task where the correct responses to a set of specific sensory stimuli varied systematically across different contexts. The correct response depended on the stimulus (A,B,C,D) and context quadrant (1,2,3,4). The possible 16 stimulus-context combinations were associated with one of two responses (X,Y), one of which was correct for half of the combinations. The correct responses varied symmetrically across contexts. This allowed responses to previously unseen stimuli (probe stimuli) to be generalized from stimuli that had been presented previously. By testing the simulation on two or more stimuli that the network had never seen in a particular context, we could test whether the correct response on the novel stimuli could be generated based on knowledge of the correct responses in other contexts. We tested this generalization capability with a Deep Belief Network (DBN), Multi-Layer Perceptron (MLP) network, and the combination of a DBN with a linear perceptron (LP). Overall, the combination of the DBN and LP had the highest success rate for generalization.

  18. Deep Belief Networks Learn Context Dependent Behavior

    OpenAIRE

    Raudies, Florian; Zilli, Eric A.; Hasselmo, Michael E.

    2014-01-01

    With the goal of understanding behavioral mechanisms of generalization, we analyzed the ability of neural networks to generalize across context. We modeled a behavioral task where the correct responses to a set of specific sensory stimuli varied systematically across different contexts. The correct response depended on the stimulus (A,B,C,D) and context quadrant (1,2,3,4). The possible 16 stimulus-context combinations were associated with one of two responses (X,Y), one of which was correct f...

  19. Context-dependent ATC complexity metric

    NARCIS (Netherlands)

    Mercado Velasco, G.A.; Borst, C.

    2015-01-01

    Several studies have investigated Air Traffic Control (ATC) complexity metrics in a search for a metric that could best capture workload. These studies have shown how daunting the search for a universal workload metric (one that could be applied in different contexts: sectors, traffic patterns,

  20. Context-dependent effects on the hydrophilicity/hydrophobicity of side-chains during reversed-phase high-performance liquid chromatography: Implications for prediction of peptide retention behaviour.

    Science.gov (United States)

    Mant, C T; Hodges, R S

    2006-09-01

    The present study set out to investigate whether observed relative hydrophilicity/hydrophobicity values of positively charged side-chains (with Lys and Arg as representative side-chains) or hydrophobic side-chains (with Ile as the representative side-chain) were context-dependent, i.e., did such measured values vary depending on characteristics of the peptides within which such side-chains are substituted (overall peptide hydrophobicity, number of positive charges) and/or properties of the mobile phase (anionic counterions of varying hydrophobicity and concentration)? Reversed-phase high-performance liquid chromatography (RP-HPLC) was applied to two series of four synthetic peptide analogues (+1, +2, +3 and +4 net charge), the only difference between the two peptide series being the substitution of one hydrophobic Ile residue for a Gly residue, in the presence of anionic ion-pairing reagents of varying hydrophobicity (HCOOH approximately H3PO4 < TFA < PFPA < HFBA) and concentration (2-50 mM). RP-HPLC of these peptide series revealed that the relative hydrophilicity of Lys and Arg side-chains in the peptides increased with peptide hydrophobicity. In addition the relative hydrophobicity of Ile decreased dramatically with an increase in the number of positive charges in the peptide, this hydrophobicity decrease being of greater magnitude as the hydrophobicity of the anionic ion-pairing reagent increased. These results have significant implications in the prediction of peptide retention times for proteomic applications.

  1. Context dependent development of lymphoid organ mesenchymal subsets fromBP3-Gp38+ PDGFRβ++CD34+ vascular adventitial precursors

    DEFF Research Database (Denmark)

    Sitnik, Katarzyna Maria; Wendland, Kerstin; Weishaupt, Holger

    Lymphoid associated mesenchymal stromal cells are believed to play essential roles in immune and organ homeostasis however our knowledge regarding the functional heterogenity and ontogeny of these cells remains limited.......Lymphoid associated mesenchymal stromal cells are believed to play essential roles in immune and organ homeostasis however our knowledge regarding the functional heterogenity and ontogeny of these cells remains limited....

  2. Functional

    Directory of Open Access Journals (Sweden)

    Fedoua Gandia

    2014-07-01

    Full Text Available The study was carried out to investigate the effects of inhaled Mg alone and associated with F in the treatment of bronchial hyperresponsiveness. 43 male Wistar rats were randomly divided into four groups and exposed to inhaled NaCl 0.9%, MeCh, MgSO4 and MgF2. Pulmonary changes were assessed by means of functional tests and quantitative histological examination of lungs and trachea. Results revealed that delivery of inhaled Mg associated with F led to a significant decrease of total lung resistance better than inhaled Mg alone (p < 0.05. Histological examinations illustrated that inhaled Mg associated with F markedly suppressed muscular hypertrophy (p = 0.034 and bronchoconstriction (p = 0.006 in MeCh treated rats better than inhaled Mg alone. No histological changes were found in the trachea. This study showed that inhaled Mg associated with F attenuated the main principle of the central components of changes in MeCh provoked experimental asthma better than inhaled Mg alone, potentially providing a new therapeutic approach against asthma.

  3. Microbial Metalloproteinases Mediate Sensing of Invading Pathogens and Activate Innate Immune Responses in the Lepidopteran Model Host Galleria mellonella▿

    Science.gov (United States)

    Altincicek, Boran; Linder, Monica; Linder, Dietmar; Preissner, Klaus T.; Vilcinskas, Andreas

    2007-01-01

    Thermolysin-like metalloproteinases such as aureolysin, pseudolysin, and bacillolysin represent virulence factors of diverse bacterial pathogens. Recently, we discovered that injection of thermolysin into larvae of the greater wax moth, Galleria mellonella, mediated strong immune responses. Thermolysin-mediated proteolysis of hemolymph proteins yielded a variety of small-sized (thermolysin, as described for bacterial lipopolysaccharides (LPS), that results in subsequent prophenoloxidase activation leading to melanization, an elementary immune defense reaction of insects. Quantitative real-time reverse transcription-PCR analyses of the expression of immune-related genes encoding the inducible metalloproteinase inhibitor, gallerimycin, and lysozyme demonstrated increased transcriptional rates after challenge with purified protfrags similar to rates after challenge with LPS. Additionally, we determined the induction of a similar spectrum of immune-responsive proteins that were secreted into the hemolymph by using comparative proteomic analyses of hemolymph proteins from untreated larvae and from larvae that were challenged with either protfrags or LPS. Since G. mellonella was recently established as a valuable pathogenicity model for Cryptococcus neoformans infection, the present results add to our understanding of the mechanisms of immune responses in G. mellonella. The obtained results support the proposed danger model, which suggests that the immune system senses endogenous alarm signals during infection besides recognition of microbial pattern molecules. PMID:17074843

  4. The relativity of biological function.

    Science.gov (United States)

    Laubichler, Manfred D; Stadler, Peter F; Prohaska, Sonja J; Nowick, Katja

    2015-12-01

    Function is a central concept in biological theories and explanations. Yet discussions about function are often based on a narrow understanding of biological systems and processes, such as idealized molecular systems or simple evolutionary, i.e., selective, dynamics. Conflicting conceptions of function continue to be used in the scientific literature to support certain claims, for instance about the fraction of "functional DNA" in the human genome. Here we argue that all biologically meaningful interpretations of function are necessarily context dependent. This implies that they derive their meaning as well as their range of applicability only within a specific theoretical and measurement context. We use this framework to shed light on the current debate about functional DNA and argue that without considering explicitly the theoretical and measurement contexts all attempts to integrate biological theories are prone to fail.

  5. Exploring the Context Dependency of the PSM-Performance Relationship

    DEFF Research Database (Denmark)

    Lynggard, Mikkel; Pedersen, Mogens Jin; Andersen, Lotte Bøgh

    2016-01-01

    The public service motivation (PSM) of public employees matters to their performance at work. Yet research on how context factors moderate the PSM–performance relationship is sparse. This article shows how the PSM–performance relationship may depend on two context factors: (a) the extent of work ...

  6. Significance of chemical recognition cues is context dependent in ants

    DEFF Research Database (Denmark)

    Bos, N.; Guerrieri, F.J.; d'Ettorre, P.

    2010-01-01

    used as training odour in our experiments. This suggests that ants, like some, but not all other insects, show interactions between different modalities (i.e. olfactory and visual), and can treat complex chemical cues differently, according to the context in which they are perceived. This plasticity...

  7. The sound of arousal in music is context-dependent.

    Science.gov (United States)

    Blumstein, Daniel T; Bryant, Gregory A; Kaye, Peter

    2012-10-23

    Humans, and many non-human animals, produce and respond to harsh, unpredictable, nonlinear sounds when alarmed, possibly because these are produced when acoustic production systems (vocal cords and syrinxes) are overblown in stressful, dangerous situations. Humans can simulate nonlinearities in music and soundtracks through the use of technological manipulations. Recent work found that film soundtracks from different genres differentially contain such sounds. We designed two experiments to determine specifically how simulated nonlinearities in soundtracks influence perceptions of arousal and valence. Subjects were presented with emotionally neutral musical exemplars that had neither noise nor abrupt frequency transitions, or versions of these musical exemplars that had noise or abrupt frequency upshifts or downshifts experimentally added. In a second experiment, these acoustic exemplars were paired with benign videos. Judgements of both arousal and valence were altered by the addition of these simulated nonlinearities in the first, music-only, experiment. In the second, multi-modal, experiment, valence (but not arousal) decreased with the addition of noise or frequency downshifts. Thus, the presence of a video image suppressed the ability of simulated nonlinearities to modify arousal. This is the first study examining how nonlinear simulations in music affect emotional judgements. These results demonstrate that the perception of potentially fearful or arousing sounds is influenced by the perceptual context and that the addition of a visual modality can antagonistically suppress the response to an acoustic stimulus.

  8. Context-dependent lateralized feeding strategies in blue whales.

    Science.gov (United States)

    Friedlaender, Ari S; Herbert-Read, James E; Hazen, Elliott L; Cade, David E; Calambokidis, John; Southall, Brandon L; Stimpert, Alison K; Goldbogen, Jeremy A

    2017-11-20

    Lateralized behaviors benefit individuals by increasing task efficiency in foraging and anti-predator behaviors [1-4]. The conventional lateralization paradigm suggests individuals are left or right lateralized, although the direction of this laterality can vary for different tasks (e.g. foraging or predator inspection/avoidance). By fitting tri-axial movement sensors to blue whales (Balaenoptera musculus), and by recording the direction and size of their rolls during lunge feeding events, we show how these animals differ from such a paradigm. The strength and direction of individuals' lateralization were related to where and how the whales were feeding in the water column. Smaller rolls (≤180°) predominantly occurred at depth (>70 m), with whales being more likely to rotate clockwise around their longest axis (right lateralized). Larger rolls (>180°), conversely, occurred more often at shallower depths (feeding strategies may enhance foraging efficiency in environments with heterogeneous prey distributions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Bark Beetle-Fungal Symbiosis: Context Dependency in Complex Associations

    Science.gov (United States)

    Kier D. Klepzig; D.L. Six

    2004-01-01

    Recent thinking in symbiosis research has emphasized a holistic consideration of these complex interactions. Bark beetles and their associated microbes are one group which has previously not been addressed in this manner. We review the study of symbiotic interactions among bark beetles and microbes in light of this thinking. We describe the considerable progress...

  10. University students' context-dependent conscious attitudes towards ...

    African Journals Online (AJOL)

    This paper considers the results of an empirical investigation of overt language attitudes held by students attending North-West University, South Africa. Attitudes elicited from 325 students with mainly Setswana, Sesotho, Afrikaans and English as home languages are analysed comparatively. The study explores the ...

  11. Context-dependent cheating: Experimental evidence from 16 countries

    NARCIS (Netherlands)

    Pascual-ezama, David; Fosgaard, Toke R.; Cardenas, Juan Camilo; Kujal, Praveen; Veszteg, Robert; Gil-gómez De Liaño, Beatriz; Gunia, Brian; Weichselbaumer, Doris; Hilken, Katharina; Antinyan, Armenak; Delnoij, Joyce|info:eu-repo/dai/nl/371752213; Proestakis, Antonios; Tira, Michael D.; Pratomo, Yulius; Jaber-lópez, Tarek; Brañas-garza, Pablo

    2015-01-01

    Policy makers use several international indices that characterize countries according to the quality of their institutions. However, no effort has been made to study how the honesty of citizens varies across countries. This paper explores the honesty among citizens across 16 countries with 1440

  12. Context-dependent Trust Decisions with Subjective Logic

    OpenAIRE

    Cerutti, Federico; Toniolo, Alice; Oren, Nir; Norman, Timothy J.

    2013-01-01

    A decision procedure implemented over a computational trust mechanism aims to allow for decisions to be made regarding whether some entity or information should be trusted. As recognised in the literature, trust is contextual, and we describe how such a context often translates into a confidence level which should be used to modify an underlying trust value. J{\\o}sang's Subjective Logic has long been used in the trust domain, and we show that its operators are insufficient to address this pro...

  13. Context-dependent concurrent adaptation to static and moving targets.

    Directory of Open Access Journals (Sweden)

    Maria N Ayala

    Full Text Available Is the neural control of movements towards moving targets independent to that of static targets? In the following experiments, we used a visuomotor rotation adaptation paradigm to examine the extent to which adapting arm movements to static targets generalize to that of moving targets (i.e. pursuit or tracking. In the first and second experiments, we showed that adaptation to perturbed tracking movements generalizes to reaching movements; reach aftereffects following perturbed tracking were about half the size (≈9° of those produced following reach training (≈ 19°. Given these findings, in the final experiment we associated opposing perturbations (-30° and +30° with either reaching or tracking movements and presented them within the same experimental block to determine whether these contexts allow for dual adaptation. We found that the group that experienced opposing perturbations was able to reduce both reaching and tracking errors, as well as produce reach aftereffects following dual training of ≈7°, which were substantially smaller than those produced when reach training was not concurrent with tracking training. This reduction in reach aftereffects is consistent with the extent of the interference from tracking training as measured by the reach aftereffects produced when only that condition was performed. These results suggest partial, but not complete, overlap in the learning processes involved in the acquisition of tracking and reaching movements.

  14. Context Dependent Learning: Its Value and Impact for Workplace Education

    Science.gov (United States)

    Lynch, Richard; Leo, Soon; Downing, Kevin

    2006-01-01

    Purpose: The purpose of this paper is to describe how a management development programme based on situated learning theory resulted in change for individuals, organisational culture and performance. The case study illustrates how new understandings about learning in the workplace and in higher education points towards the need to take account of…

  15. Context-Dependent Modulation of GABAAR-Mediated Tonic Currents

    DEFF Research Database (Denmark)

    Patel, Bijal; Bright, Damian P; Mortensen, Martin

    2016-01-01

    of neurological disorders. Consequently, developing compounds to selectively modulate the activity of extrasynaptic GABAA receptors underlying tonic inhibition is likely to prove therapeutically useful. Here, we examine the GABAA receptor subtype selectivity of the weak partial agonist, 5-(4-piperidyl)isoxazol-3......-ol (4-PIOL), as a potential mechanism for modulating extrasynaptic GABAA receptor-mediated tonic currents. By using recombinant GABAA receptors expressed in HEK293 cells, and native GABAA receptors of cerebellar granule cells, hippocampal neurons, and thalamic relay neurons, 4-PIOL evidently...... displayed differential agonist and antagonist-type profiles, depending on the extrasynaptic GABAA receptor isoforms targeted. For neurons, this resulted in differential modulation of GABA tonic currents, depending on the cell type studied, their respective GABAA receptor subunit compositions, and critically...

  16. The Effect of Practice Schedule on Context-Dependent Learning.

    Science.gov (United States)

    Lee, Ya-Yun; Fisher, Beth E

    2018-03-02

    It is well established that random practice compared to blocked practice enhances motor learning. Additionally, while information in the environment may be incidental, learning is also enhanced when an individual performs a task within the same environmental context in which the task was originally practiced. This study aimed to disentangle the effects of practice schedule and incidental/environmental context on motor learning. Participants practiced three finger sequences under either a random or blocked practice schedule. Each sequence was associated with specific incidental context (i.e., color and location on the computer screen) during practice. The participants were tested under the conditions when the sequence-context associations remained the same or were changed from that of practice. When the sequence-context association was changed, the participants who practiced under blocked schedule demonstrated greater performance decrement than those who practiced under random schedule. The findings suggested that those participants who practiced under random schedule were more resistant to the change of environmental context.

  17. Context-dependent incremental timing cells in the primate hippocampus.

    Science.gov (United States)

    Sakon, John J; Naya, Yuji; Wirth, Sylvia; Suzuki, Wendy A

    2014-12-23

    We examined timing-related signals in primate hippocampal cells as animals performed an object-place (OP) associative learning task. We found hippocampal cells with firing rates that incrementally increased or decreased across the memory delay interval of the task, which we refer to as incremental timing cells (ITCs). Three distinct categories of ITCs were identified. Agnostic ITCs did not distinguish between different trial types. The remaining two categories of cells signaled time and trial context together: One category of cells tracked time depending on the behavioral action required for a correct response (i.e., early vs. late release), whereas the other category of cells tracked time only for those trials cued with a specific OP combination. The context-sensitive ITCs were observed more often during sessions where behavioral learning was observed and exhibited reduced incremental firing on incorrect trials. Thus, single primate hippocampal cells signal information about trial timing, which can be linked with trial type/context in a learning-dependent manner.

  18. Context-Dependent Conflation, Text Filtering and Clustering

    Science.gov (United States)

    2004-09-01

    2003). Document clustering into an unknown number of clusters using a genetic algorithm. Text, Speech and Dialogue, Proceedings, 2807. Lecture... Chameleon : A hierarchical clustering algorithm using dynamic modeling. IEEE Computer: Special Issue on Data Analysis and Mining 32(8). 68-75

  19. Context-dependent antagonism between Akt inhibitors and topoisomerase poisons.

    Science.gov (United States)

    Gálvez-Peralta, Marina; Flatten, Karen S; Loegering, David A; Peterson, Kevin L; Schneider, Paula A; Erlichman, Charles; Kaufmann, Scott H

    2014-05-01

    Signaling through the phosphatidylinositol-3 kinase (PI3K)/Akt pathway, which is aberrantly activated in >50% of carcinomas, inhibits apoptosis and contributes to drug resistance. Accordingly, several Akt inhibitors are currently undergoing preclinical or early clinical testing. To examine the effect of Akt inhibition on the activity of multiple widely used classes of antineoplastic agents, human cancer cell lines were treated with the Akt inhibitor A-443654 [(2S)-1-(1H-indol-3-yl)-3-[5-(3-methyl-2H-indazol-5-yl)pyridin-3-yl]oxypropan-2-amine; ATP-competitive] or MK-2206 (8-[4-(1-aminocyclobutyl)phenyl]-9-phenyl-2H-[1,2,4]triazolo[3,4-f][1,6]naphthyridin-3-one;dihydrochloride; allosteric inhibitor) or with small interfering RNA (siRNA) targeting phosphoinositide-dependent kinase 1 (PDK1) along with cisplatin, melphalan, camptothecin, or etoposide and assayed for colony formation. Surprisingly different results were observed when Akt inhibitors were combined with different drugs. Synergistic effects were observed in multiple cell lines independent of PI3K pathway status when A-443654 or MK-2206 was combined with the DNA cross-linking agents cisplatin or melphalan. In contrast, effects of the Akt inhibitors in combination with camptothecin or etoposide were more complicated. In HCT116 and DLD1 cells, which harbor activating PI3KCA mutations, A-443654 over a broad concentration range enhanced the effects of camptothecin or etoposide. In contrast, in cell lines lacking activating PI3KCA mutations, partial inhibition of Akt signaling synergized with camptothecin or etoposide, but higher A-443654 or MK-2206 concentrations (>80% inhibition of Akt signaling) or PDK1 siRNA antagonized the topoisomerase poisons by diminishing DNA synthesis, a process that contributes to effective DNA damage and killing by these agents. These results indicate that the effects of combining inhibitors of the PI3K/Akt pathway with certain classes of chemotherapeutic agents might be more complicated than previously recognized.

  20. Context-dependent individual behavioral consistency in Daphnia

    DEFF Research Database (Denmark)

    Heuschele, Jan; Ekvall, Mikael T.; Bianco, Giuseppe

    2017-01-01

    The understanding of consistent individual differences in behavior, often termed "personality," for adapting and coping with threats and novel environmental conditions has advanced considerably during the last decade. However, advancements are almost exclusively associated with higher-order animals...... velocity among both mothers and daughters of D. magna in a neutral environment, whereas this pattern breaks down when exposed to UVR. Our study also, for the first time, illustrates how the ontogenetic development in swimming and refuge-seeking behavior of young individuals eventually approaches......, whereas studies focusing on smaller aquatic organisms are still rare. Here, we show individual differences in the swimming behavior of Daphnia magna, a clonal freshwater invertebrate, before, during, and after being exposed to a lethal threat, ultraviolet radiation (UVR). We show consistency in swimming...

  1. Neural mechanisms underlying context-dependent shifts in risk preferences

    NARCIS (Netherlands)

    Losecaat Vermeer, A.B.; Boksem, M.A.S.; Sanfey, A.G.

    2014-01-01

    Studies of risky decision-making have demonstrated that humans typically prefer risky options after incurring a financial loss, while generally preferring safer options after a monetary gain. Here, we examined the neural processes underlying these inconsistent risk preferences by investigating the

  2. Verification of Context-Dependent Channel-Based Service Models

    NARCIS (Netherlands)

    N. Kokash (Natallia); , C. (born Köhler, , C.) Krause (Christian); E.P. de Vink (Erik Peter)

    2010-01-01

    htmlabstractThe paradigms of service-oriented computing and model-driven development are becoming of increasing importance in the eld of software engineering. According to these paradigms, new systems are composed with added value from existing stand-alone services to support business processes

  3. Sensitivity of landscape resistance estimates based on point selection functions to scale and behavioral state: Pumas as a case study

    Science.gov (United States)

    Katherine A. Zeller; Kevin McGarigal; Paul Beier; Samuel A. Cushman; T. Winston Vickers; Walter M. Boyce

    2014-01-01

    Estimating landscape resistance to animal movement is the foundation for connectivity modeling, and resource selection functions based on point data are commonly used to empirically estimate resistance. In this study, we used GPS data points acquired at 5-min intervals from radiocollared pumas in southern California to model context-dependent point selection...

  4. Induction of increased cAMP levels in articular chondrocytes blocks matrix metalloproteinase-mediated cartilage degradation, but not aggrecanase-mediated cartilage degradation

    DEFF Research Database (Denmark)

    Karsdal, Morten Asser; Sumer, Eren Ufuk; Wulf, Helle

    2007-01-01

    GAG) into culture medium, 5) immunohistochemistry with a monoclonal antibody recognizing the CTX-II epitope, and 6) toluidine blue staining of proteoglycans. MMP expression and activity were assessed by gelatin zymography. RESULTS: OSM and TNF induced an 8,000% increase in CTX-II compared with control (P ....001). Both forskolin and IBMX dose-dependently inhibited release of CTX-II (P 80%). OSM and TNF stimulated MMP expression as visualized by zymography, and MMP expression was dose...

  5. Disabled-2 is a FOXP3 target gene required for regulatory T cell function

    OpenAIRE

    Jain, N; Nguyen, H; Friedline, RH; Malhotra, N; Brehm, M; Koyonagi, M; Bix, M; Cooper, JA; Chambers, CA; Kang, J

    2009-01-01

    FOXP3 expressing regulatory T cells are vital for maintaining peripheral T cell tolerance and homeostasis. The mechanisms by which FOXP3 target genes orchestrate context-dependent Treg cell function are largely unknown. Here we show that in mouse peripheral lymphocytes, the Drosophila Disabled-2 (Dab2) homolog, a gene that is involved in enhancing TGFβ responses, is exclusively expressed in FOXP3+ regulatory T cells. Dab2 is a direct target of FOXP3 and regulatory T cells lacking DAB2 are fun...

  6. Three experimental approaches to measure the social context dependence of prejudice communication and discriminatory behavior.

    Science.gov (United States)

    Beyer, Heiko; Liebe, Ulf

    2015-01-01

    Empirical research on discrimination is faced with crucial problems stemming from the specific character of its object of study. In democratic societies the communication of prejudices and other forms of discriminatory behavior is considered socially undesirable and depends on situational factors such as whether a situation is considered private or whether a discriminatory consensus can be assumed. Regular surveys thus can only offer a blurred picture of the phenomenon. But also survey experiments intended to decrease the social desirability bias (SDB) so far failed in systematically implementing situational variables. This paper introduces three experimental approaches to improve the study of discrimination and other topics of social (un-)desirability. First, we argue in favor of cognitive context framing in surveys in order to operationalize the salience of situational norms. Second, factorial surveys offer a way to take situational contexts and substitute behavior into account. And third, choice experiments - a rather new method in sociology - offer a more valid method of measuring behavioral characteristics compared to simple items in surveys. All three approaches - which may be combined - are easy to implement in large-scale surveys. Results of empirical studies demonstrate the fruitfulness of each of these approaches. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. On the context dependence of emotion displays : Perceptions of gold medalists’ expressions of pride

    NARCIS (Netherlands)

    van Osch, Yvette; Zeelenberg, Marcel; Breugelmans, Seger M.

    2016-01-01

    In spite of various claims for cross-cultural differences in the experience of pride, studies on the expression of pride have revealed few cross-cultural differences. Five studies using archival data from Olympic and national championships do show cross-cultural differences in the expression of

  8. On the context dependence of emotion displays : Perceptions of gold medalists' expressions of pride

    NARCIS (Netherlands)

    van Osch, Y.M.J.; Zeelenberg, M.; Breugelmans, S.M.

    2016-01-01

    In spite of various claims for cross-cultural differences in the experience of pride, studies on the expression of pride have revealed few cross-cultural differences. Five studies using archival data from Olympic and national championships do show cross-cultural differences in the expression of

  9. Social Augmented Reality: Enhancing Context-Dependent Communication and Informal Learning at Work

    Science.gov (United States)

    Pejoska, Jana; Bauters, Merja; Purma, Jukka; Leinonen, Teemu

    2016-01-01

    Our design proposal of social augmented reality (SoAR) grows from the observed difficulties of practical applications of augmented reality (AR) in workplace learning. In our research we investigated construction workers doing physical work in the field and analyzed the data using qualitative methods in various workshops. The challenges related to…

  10. Smart Questions : Context-dependent mobile information exchange for military operations

    NARCIS (Netherlands)

    Streefkerk, J.W.; Heuvelink, A.

    2014-01-01

    During military mISSIOns, mobile devices allow information exchange between distributed groups of soldiers. As the context of use changes frequently and more (unstructured) information becomes available during missions, the challenge is to ensure that the right information reaches the right

  11. Context-dependent JPEG backward-compatible high-dynamic range image compression

    Science.gov (United States)

    Korshunov, Pavel; Ebrahimi, Touradj

    2013-10-01

    High-dynamic range (HDR) imaging is expected, together with ultrahigh definition and high-frame rate video, to become a technology that may change photo, TV, and film industries. Many cameras and displays capable of capturing and rendering both HDR images and video are already available in the market. The popularity and full-public adoption of HDR content is, however, hindered by the lack of standards in evaluation of quality, file formats, and compression, as well as large legacy base of low-dynamic range (LDR) displays that are unable to render HDR. To facilitate the wide spread of HDR usage, the backward compatibility of HDR with commonly used legacy technologies for storage, rendering, and compression of video and images are necessary. Although many tone-mapping algorithms are developed for generating viewable LDR content from HDR, there is no consensus of which algorithm to use and under which conditions. We, via a series of subjective evaluations, demonstrate the dependency of the perceptual quality of the tone-mapped LDR images on the context: environmental factors, display parameters, and image content itself. Based on the results of subjective tests, it proposes to extend JPEG file format, the most popular image format, in a backward compatible manner to deal with HDR images also. An architecture to achieve such backward compatibility with JPEG is proposed. A simple implementation of lossy compression demonstrates the efficiency of the proposed architecture compared with the state-of-the-art HDR image compression.

  12. Tree diversity and species identity effects on soil fungi, protists and animals are context dependent

    Czech Academy of Sciences Publication Activity Database

    Tedersoo, L.; Bahram, M.; Cajthaml, Tomáš; Polme, S.; Hiiesalu, I.; Anslan, S.; Harend, H.; Buegger, F.; Pritsch, K.; Koricheva, J.; Abarenkov, K.

    2016-01-01

    Roč. 10, č. 2 (2016), s. 346-362 ISSN 1751-7362 Institutional support: RVO:61388971 Keywords : INTERNAL TRANSCRIBED SPACER * ECTOMYCORRHIZAL FUNGI * COMMUNITY STRUCTURE Subject RIV: EE - Microbiology, Virology Impact factor: 9.664, year: 2016

  13. No evidence for visual context-dependency of olfactory learning in Drosophila

    Science.gov (United States)

    Yarali, Ayse; Mayerle, Moritz; Nawroth, Christian; Gerber, Bertram

    2008-08-01

    How is behaviour organised across sensory modalities? Specifically, we ask concerning the fruit fly Drosophila melanogaster how visual context affects olfactory learning and recall and whether information about visual context is getting integrated into olfactory memory. We find that changing visual context between training and test does not deteriorate olfactory memory scores, suggesting that these olfactory memories can drive behaviour despite a mismatch of visual context between training and test. Rather, both the establishment and the recall of olfactory memory are generally facilitated by light. In a follow-up experiment, we find no evidence for learning about combinations of odours and visual context as predictors for reinforcement even after explicit training in a so-called biconditional discrimination task. Thus, a ‘true’ interaction between visual and olfactory modalities is not evident; instead, light seems to influence olfactory learning and recall unspecifically, for example by altering motor activity, alertness or olfactory acuity.

  14. Olfactory Context-Dependent Memory and the Effects of Affective Congruency.

    Science.gov (United States)

    Hackländer, Ryan P M; Bermeitinger, Christina

    2017-10-31

    Odors have been claimed to be particularly effective mnemonic cues, possibly because of the strong links between olfaction and emotion processing. Indeed, past research has shown that odors can bias processing towards affectively congruent material. In order to determine whether this processing bias translates to memory, we conducted 2 olfactory-enhanced-context memory experiments where we manipulated affective congruency between the olfactory context and to-be-remembered material. Given the presumed importance of valence to olfactory perception, we hypothesized that memory would be best for affectively congruent material in the olfactory enhanced context groups. Across the 2 experiments, groups which encoded and retrieved material in the presence of an odorant exhibited better memory performance than groups that did not have the added olfactory context during encoding and retrieval. While context-enhanced memory was exhibited in the presence of both pleasant and unpleasant odors, there was no indication that memory was dependent on affective congruency between the olfactory context and the to-be-remembered material. While the results provide further support for the notion that odors can act as powerful contextual mnemonic cues, they call into question the notion that affective congruency between context and focal material is important for later memory performance. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. University students' context-dependent conscious attitudes towards the official South African languages

    NARCIS (Netherlands)

    Hilton, Nanna Haug

    2010-01-01

    This paper considers the results of an empirical investigation of overt language attitudes held by students attending North-West University, South Africa. Attitudes elicited from 325 students with mainly Setswana, Sesotho, Afrikaans and English as home languages are analysed comparatively. The study

  16. Context-Dependent Plastic Response during Egg-Laying in a Widespread Newt Species

    OpenAIRE

    T?th, Zolt?n

    2015-01-01

    Previous research on predator-induced phenotypic plasticity mostly focused on responses in morphology, developmental time and/or behaviour during early life stages, but the potential significance of anticipatory parental responses has been investigated less often. In this study I examined behavioural and maternal responses of gravid female smooth newts, Lissotriton vulgaris, in the presence of chemical cues originating from invertebrate predators, Acilius sulcatus water beetles and Aeshna cya...

  17. Context-Dependent Plastic Response during Egg-Laying in a Widespread Newt Species.

    Science.gov (United States)

    Tóth, Zoltán

    2015-01-01

    Previous research on predator-induced phenotypic plasticity mostly focused on responses in morphology, developmental time and/or behaviour during early life stages, but the potential significance of anticipatory parental responses has been investigated less often. In this study I examined behavioural and maternal responses of gravid female smooth newts, Lissotriton vulgaris, in the presence of chemical cues originating from invertebrate predators, Acilius sulcatus water beetles and Aeshna cyanea dragonfly larvae. More specifically, I tested the extent of oviposition preference, plasticity in egg-wrapping behaviour and plasticity in egg size when females had the possibility to lay eggs at oviposition sites with and without predator cues during overnight trials. I found that individuals did not avoid laying eggs in the environment with predator cues; however, individuals that deposited eggs into both environments adjusted the size of the laid eggs to the perceived environment. Females deposited larger eggs earlier in the season but egg size decreased with time in the absence of predator cues, whereas individuals laid eggs of average size throughout the investigated reproductive period when such cues were present. Also, egg size was found to be positively related to hatching success. Individuals did not adjust their wrapping behaviour to the presence of predator cues, but females differed in the extent of egg-wrapping between ponds. Females' body mass and tail depth were also different between ponds, whereas their body size was positively associated with egg size. According to these results, female smooth newts have the potential to exhibit activational plasticity and invest differently into eggs depending on temporal and environmental factors. Such an anticipatory response may contribute to the success of this caudate species under a wide range of predator regimes at its natural breeding habitats.

  18. Context Dependence of Students' Views about the Role of Equations in Understanding Biology

    Science.gov (United States)

    Watkins, Jessica; Elby, Andrew

    2013-01-01

    Students' epistemological views about biology--their ideas about what "counts" as learning and understanding biology--play a role in how they approach their courses and respond to reforms. As introductory biology courses incorporate more physics and quantitative reasoning, student attitudes about the role of equations in biology become…

  19. Context-dependent enhancer selection confers alternate modes of notch regulation on argos.

    Science.gov (United States)

    Housden, Benjamin E; Terriente-Felix, Ana; Bray, Sarah J

    2014-02-01

    Wiring between signaling pathways differs according to context, as exemplified by interactions between Notch and epidermal growth factor receptor (EGFR) pathways, which are cooperative in some contexts but antagonistic in others. To investigate mechanisms that underlie different modes of cross talk, we have focused on argos, an EGFR pathway regulator in Drosophila melanogaster which is upregulated by Notch in adult muscle progenitors but is repressed in the wing. Results show that the alternate modes of cross talk depend on the engagement of enhancers with opposite regulatory logic, which are selected by context-determining factors. This is likely to be a general mechanism for enabling the wiring between these pathways to switch according to context.

  20. The Artificial Milk Feeding or Breast Feeding: Context Dependant Practices. Brazil, 1960-1988

    Directory of Open Access Journals (Sweden)

    Suely Teresinha Schmidt Passos de Amorim

    2008-05-01

    Full Text Available The aim of this study was the discourse analysis on breast feeding from 1960 through 1988 in Brazil, on articles published in famous women magazines. The focus of the study is the History area, mainly the Feeding History, with an interdisciplinary approach. The initial period – 1960 – is linked with the end of Juscelino Kubitschek’s Government, when the economy, guided by the industrial sector, had grown in relative and absolute terms. The final period – 1988 – characterizes the Brazilian Norm of Suckling Feeding Business approval, which restricted the milk powder marketing. The change on discourses enunciates was very evident. During the period the artificial breast feeding was stimulated, the discourse main enunciate was the women’s condition, women’s valorization and their right of freedom. With the re-encouragement to the women breast feeding the discourses were totally on this usage defense, minimizing women’s daily difficulties.

  1. Context-dependent fitness effects of behavioral manipulation by a parasitoid

    NARCIS (Netherlands)

    Janssen, A.; Grosman, A.H.; Cordeiro, E.G.; de Brito, E.F.; Fonseca, J.O.; Colares, F.; Pallini, A.; Lima, E.R.; Sabelis, M.W.

    2010-01-01

    Many true parasites and parasitoids modify the behavior of their host, and most of these changes are thought to benefit the parasites. However, field tests of this hypothesis are scarce. We previously showed that braconid parasitoids (Glyptapanteles sp.) induce their caterpillar host (Thyrinteina

  2. Dynamic learning and context-dependence in sequential, attribute-based, stated-preference valuation questions

    Science.gov (United States)

    Thomas P. Holmes; Kevin J. Boyle

    2005-01-01

    A hybrid stated-preference model is presented that combines the referendum contingent valuation response format with an experimentally designed set of attributes. A sequence of valuation questions is asked to a random sample in a mailout mail-back format. Econometric analysis shows greater discrimination between alternatives in the final choice in the sequence, and the...

  3. Context dependence of acorn handling by the Algerian mouse (Mus spretus)

    Science.gov (United States)

    Gallego, D.; Morán-López, T.; Torre, I.; Navarro-Castilla, Á.; Barja, I.; Díaz, M.

    2017-10-01

    Perceived predation risk and competition for acorns are expected to affect scatter-hoarding decisions by Algerian mice (Mus spretus). We manipulated both factors by means of predator fecal scents and ungulate exclosures. We hypothesized that high-risk perception and ungulate presence would promote acorn dispersal. In the former case, it would stimulate acorn mobilization to safe microhabitats rather than in situ consumption. In the latter, increased competition for acorns would promote their storage for later consumption. We also expected that mice would adapt their foraging behavior to previous experience modulating the strength of these effects. In the presence of ungulates, mice focused their foraging activities on food acquisition at the expenses of vigilant behaviors. However, a more efficient foraging did not entail enhanced dispersal services. Lack of anti-predatory cover in tree surroundings may have deterred mice from transporting seeds outside canopies. Increased risk interacted with previous experience. In control trees (no predator odor), mice confidence increased throughout the night resulting in decreased vigilance and enhanced acorn mobilization rates. In contrast, in risky conditions (trees with predator odor) mice maintained a base-line vigilant behavior. Contrary to our expectations, increased risk did not result in higher acorn mobilization, but the opposite. Again, the scarcity of safe microhabitats for mobilization may have been the underlying cause of this behavior. Our results show that successful acorn dispersal depends, at least partly, on plant-animal relationships that are beyond the oak-rodent mutualism. Thus, any conservation policy aimed at restoring natural regeneration of oaks should take into account the interaction network in which oak-rodent encounters are embedded. In addition, they suggest that mice incorporate direct and indirect cues of risks (habitat structure) through recent experience. A better understanding of this process will improve our ability to incorporate such temporal and spatial variability in models of acorn dispersal.

  4. Physiological impact and context dependency of transcriptional responses : A chemostat study in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Tai, S.L.

    2007-01-01

    This thesis is a compilation of a four-year PhD project on bakers' yeast (Saccharomyces cerevisiae). Since the entire S. cerevisiae genome sequence became available in 1996, DNA-microarray analysis has become a popular high-information-density tool for analyzing gene expression in this important

  5. Glucocorticoids exert context-dependent effects on cells of the joint in vitro

    DEFF Research Database (Denmark)

    Madsen, Suzi H; Andreassen, Kim V; Christensen, Søren T

    2011-01-01

    Glucocorticoids are known to attenuate bone formation in vivo leading to decreased bone volume and increased risk of fractures, whereas effects on the joint tissue are less characterized. However, glucocorticoids appear to have a reducing effect on inflammation and pain in osteoarthritis....... This study aimed at characterizing the effect of glucocorticoids on chondrocytes, osteoclasts, and osteoblasts....

  6. Glucocorticoids exert context-dependent effects on cells of the joint in vitro.

    Science.gov (United States)

    Madsen, Suzi H; Andreassen, Kim V; Christensen, Søren T; Karsdal, Morten A; Sverdrup, Francis M; Bay-Jensen, Anne-Christine; Henriksen, Kim

    2011-12-11

    Glucocorticoids are known to attenuate bone formation in vivo leading to decreased bone volume and increased risk of fractures, whereas effects on the joint tissue are less characterized. However, glucocorticoids appear to have a reducing effect on inflammation and pain in osteoarthritis. This study aimed at characterizing the effect of glucocorticoids on chondrocytes, osteoclasts, and osteoblasts. We used four model systems to investigate how glucocorticoids affect the cells of the joint; two intact tissues (femoral head- and cartilage-explants), and two separate cell cultures of osteoblasts (2T3-pre-osteoblasts) and osteoclasts (CD14(+)-monocytes). The model systems were cultured in the presence of two glucocorticoids; prednisolone or dexamethasone. To induce anabolic and catabolic conditions, cultures were activated by insulin-like growth factor I/bone morphogenetic protein 2 and oncostatin M/tumor necrosis factor-α, respectively. Histology and markers of bone- and cartilage-turnover were used to evaluate effects of glucocorticoid treatment. Prednisolone treatment decreased collagen type-II degradation in immature cartilage, whereas glucocorticoids did not affect collagen type-II in mature cartilage. Glucocorticoids had an anti-catabolic effect on catabolic-activated cartilage from a bovine stifle joint and murine femoral heads. Glucocorticoids decreased viability of all bone cells, leading to a reduction in osteoclastogenesis and bone resorption; however, bone morphogenetic protein 2-stimulated osteoblasts increased bone formation, as opposed to non-stimulated osteoblasts. Using highly robust in vitro models of bone and cartilage turnover, we suggest that effects of glucocorticoids highly depend on the activation and differential stage of the cell targeted in the joint. Present data indicated that glucocorticoid treatment may be beneficial for articular cartilage, although detrimental effects on bone should be taken into account. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Context-dependent preferences in starlings: linking ecology, foraging and choice.

    Directory of Open Access Journals (Sweden)

    Marco Vasconcelos

    Full Text Available Foraging animals typically encounter opportunities that they either pursue or skip, but occasionally meet several alternatives simultaneously. Behavioural ecologists predict preferences using absolute properties of each option, while decision theorists focus on relative evaluations at the time of choice. We use European starlings (Sturnus vulgaris to integrate ecological reasoning with decision models, linking and testing hypotheses for value acquisition and choice mechanism. We hypothesise that options' values depend jointly on absolute attributes, learning context, and subject's state. In simultaneous choices, preference could result either from comparing subjective values using deliberation time, or from processing each alternative independently, without relative comparisons. The combination of the value acquisition hypothesis and independent processing at choice time has been called the Sequential Choice Model. We test this model with options equated in absolute properties to exclude the possibility of preference being built at the time of choice. Starlings learned to obtain food by responding to four stimuli in two contexts. In context [AB], they encountered options A5 or B10 in random alternation; in context [CD], they met C10 or D20. Delay to food is denoted, in seconds, by the suffixes. Observed latency to respond (Li to each option alone (our measure of value ranked thus: LA≈LC

  8. Cognate effects in sentence context depend on word class, L2 proficiency, and task

    NARCIS (Netherlands)

    Bultena, S.S.; Dijkstra, A.F.J.; Hell, J.G. van

    2014-01-01

    Noun translation equivalents that share orthographic and semantic features, called "cognates", are generally recognized faster than translation equivalents without such overlap. This cognate effect, which has also been obtained when cognates and noncognates were embedded in a sentence context,

  9. Context-dependent Semantic Processing in the Human Brain: Evidence from Idiom Comprehension

    NARCIS (Netherlands)

    Rommers, J.; Dijkstra, A.F.J.; Bastiaansen, M.C.M.

    2013-01-01

    Language comprehension involves activating word meanings and integrating them with the sentence context. This study examined whether these routines are carried out even when they are theoretically unnecessary, namely, in the case of opaque idiomatic expressions, for which the literal word meanings

  10. Context-dependent semantic processing in the human brain: Evidence from idiom comprehension

    NARCIS (Netherlands)

    Rommers, J.; Dijkstra, A.F.J.; Bastiaansen, M.C.M.

    2013-01-01

    Language comprehension involves activating word meanings and integrating them with the sentence context. This study examined whether these routines are carried out even when they are theoretically unnecessary, namely, in the case of opaque idiomatic expressions, for which the literal word meanings

  11. Context-dependent player's movement interpretation: application to adaptive game development

    Science.gov (United States)

    Picard, Francois; Estraillier, Pascal

    2010-02-01

    Video games are more and more controlled by the real movements of the player. However, the player is constrained by the system devices, imposing a limited vocabulary of actions associated with a set of unnatural movements. To introduce more entertaining video games to players, a component-based architecture is proposed. It has been acknowledged as the starting point for the development of adaptive applications based on the hypothesis of a high level dialogue between the system and the player. The system adaptability relies on interpretation mechanisms of the player behaviors. These behaviors are defined through the representation of the real movements of the player who freely interacts with the 3D elements composing an immersive virtual environment, following a given game scenario. The efficient interpretation of the player movements relies on the introduction in the system of the management of the scene's context. The contextual information not only helps to determine the true meaning of an observed behavior but also makes the system to adapt its processes regarding this interpretation, while managing its hardware and software resources efficiently. A commercial motion capture interface has been enhanced by the elaboration of such a system.

  12. Embodied Semantics 150 Years After Broca: Context-Dependent Negation in Novelistic Storytelling

    Directory of Open Access Journals (Sweden)

    Anatole Pierre Fuksas

    2013-08-01

    Full Text Available The present study capitalizes on recent advances in neurophysiology concerning the involvement of the sensory-motor system in language recognition and understanding during reading and listening so as to explain the various roles played by negation in novelistic descriptions since the medieval origins of the genre. Textual evidence from a famous medieval verse novel, Chrétien de Troyes’ Chevalier de la Charrette, demonstrates that negation does not simply complicate the processing of a given description. Indeed, negative descriptions can be completely understood only if fully integrated in a complex context which entails the conceptual representation of the negated state of affairs.

  13. Context-dependent activation of reduced autobiographical memory specificity as an avoidant coping style.

    Science.gov (United States)

    Debeer, Elise; Raes, Filip; Williams, J Mark G; Hermans, Dirk

    2011-12-01

    According to the affect-regulation hypothesis (Williams et al., 2007), reduced autobiographical memory specificity (rAMS) or overgeneral memory (OGM) might be considered a cognitive avoidance strategy; that is, people learn to avoid the emotionally painful consequences associated with the retrieval of specific negative memories. Based on this hypothesis, one would predict significant negative associations between AMS and avoidant coping. However, studies investigating this prediction have led to equivocal results. In the present study we tested a possible explanation for these contradictory findings. It was hypothesized that rAMS (in part) reflects an avoidant coping strategy, which might only become apparent under certain conditions, that is, conditions that signal the possibility of 'danger.' To test this hypothesis, we assessed AMS and behavioral avoidance but experimentally manipulated the instructions. In the neutral condition, two parallel versions of the Autobiographical Memory Test (AMT) were presented under neutral instructions. In the threat condition, the first AMT was presented under neutral instructions, while the second AMT was presented under 'threat instructions.' Results showed no significant correlations between avoidance and OGM under neutral conditions but significant and markedly stronger correlations under threat conditions, with more avoidance being associated with fewer specific and more categoric memories. In addition, high avoiders showed a stronger reduction in AMS in the threat condition as compared with the neutral condition, while low avoiders showed no such difference between conditions. The data confirm that OGM can be considered as part of a broader avoidant coping style. However, more importantly, they show that, at least in nonclinical individuals, the activation of this coping style may depend on the context. (c) 2011 APA, all rights reserved.

  14. Context Dependent Effects of Chimeric Peptide Morpholino Conjugates Contribute to Dystrophin Exon-skipping Efficiency

    Directory of Open Access Journals (Sweden)

    HaiFang Yin

    2013-01-01

    Full Text Available We have recently reported that cell-penetrating peptides (CPPs and novel chimeric peptides containing CPP (referred as B peptide and muscle-targeting peptide (referred as MSP motifs significantly improve the systemic exon-skipping activity of morpholino phosphorodiamidate oligomers (PMOs in dystrophin-deficient mdx mice. In the present study, the general mechanistic significance of the chimeric peptide configuration on the activity and tissue uptake of peptide conjugated PMOs in vivo was investigated. Four additional chimeric peptide-PMO conjugates including newly identified peptide 9 (B-9-PMO and 9-B-PMO and control peptide 3 (B-3-PMO and 3-B-PMO were tested in mdx mice. Immunohistochemical staining, RT-PCR and western blot results indicated that B-9-PMO induced significantly higher level of exon skipping and dystrophin restoration than its counterpart (9-B-PMO, further corroborating the notion that the activity of chimeric peptide-PMO conjugates is dependent on relative position of the tissue-targeting peptide motif within the chimeric peptide with respect to PMOs. Subsequent mechanistic studies showed that enhanced cellular uptake of B-MSP-PMO into muscle cells leads to increased exon-skipping activity in comparison with MSP-B-PMO. Surprisingly, further evidence showed that the uptake of chimeric peptide-PMO conjugates of both orientations (B-MSP-PMO and MSP-B-PMO was ATP- and temperature-dependent and also partially mediated by heparan sulfate proteoglycans (HSPG, indicating that endocytosis is likely the main uptake pathway for both chimeric peptide-PMO conjugates. Collectively, our data demonstrate that peptide orientation in chimeric peptides is an important parameter that determines cellular uptake and activity when conjugated directly to oligonucleotides. These observations provide insight into the design of improved cell targeting compounds for future therapeutics studies.

  15. On the context dependency of implicit self-esteem in social anxiety disorder.

    Science.gov (United States)

    Hiller, Thomas S; Steffens, Melanie C; Ritter, Viktoria; Stangier, Ulrich

    2017-12-01

    Cognitive models assume that negative self-evaluations are automatically activated in individuals with Social Anxiety Disorder (SAD) during social situations, increasing their individual level of anxiety. This study examined automatic self-evaluations (i.e., implicit self-esteem) and state anxiety in a group of individuals with SAD (n = 45) and a non-clinical comparison group (NC; n = 46). Participants were randomly assigned to either a speech condition with social threat induction (giving an impromptu speech) or to a no-speech condition without social threat induction. We measured implicit self-esteem with an Implicit Association Test (IAT). Implicit self-esteem differed significantly between SAD and NC groups under the speech condition but not under the no-speech condition. The SAD group showed lower implicit self-esteem than the NC group under the speech-condition. State anxiety was significantly higher under the speech condition than under the no-speech condition in the SAD group but not in the NC group. Mediation analyses supported the idea that for the SAD group, the effect of experimental condition on state anxiety was mediated by implicit self-esteem. The causal relation between implicit self-esteem and state anxiety could not be determined. The findings corroborate hypotheses derived from cognitive models of SAD: Automatic self-evaluations were negatively biased in individuals with SAD facing social threat and showed an inverse relationship to levels of state anxiety. However, automatic self-evaluations in individuals with SAD can be unbiased (similar to NC) in situations without social threat. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Context-dependent survival, fecundity and predicted population-level consequences of brucellosis in African buffalo

    Science.gov (United States)

    Gorsich, Erin E.; Ezenwa, Vanessa O.; Cross, Paul C.; Bengis, Roy G.; Jolles, Anna E.

    2015-01-01

    Chronic infections may have negative impacts on wildlife populations, yet their effects are difficult to detect in the absence of long-term population monitoring. Brucella abortus, the bacteria responsible for bovine brucellosis, causes chronic infections and abortions in wild and domestic ungulates, but its impact on population dynamics is not well understood.

  17. Context-dependent regulation of feeding behaviour by the insulin receptor, DAF-2, in Caenorhabditis elegans.

    Science.gov (United States)

    Dillon, James; Holden-Dye, Lindy; O'Connor, Vincent; Hopper, Neil A

    2016-06-01

    Insulin signalling plays a significant role in both developmental programmes and pathways modulating the neuronal signalling that controls adult behaviour. Here, we have investigated insulin signalling in food-associated behaviour in adult C. elegans by scoring locomotion and feeding on and off bacteria, the worm's food. This analysis used mutants (daf-2, daf-18) of the insulin signalling pathway, and we provide evidence for an acute role for insulin signalling in the adult nervous system distinct from its impact on developmental programmes. Insulin receptor daf-2 mutants move slower than wild type both on and off food and showed impaired locomotory responses to food deprivation. This latter behaviour is manifest as a failure to instigate dispersal following prolonged food deprivation and suggests a role for insulin signalling in this adaptive response. Insulin receptor daf-2 mutants are also deficient in pharyngeal pumping on food and off food. Pharmacological analysis showed the pharynx of daf-2 is selectively compromised in its response to 5-HT compared to the excitatory neuropeptide FLP-17. By comparing the adaptive pharyngeal behaviour in intact worms and isolated pharyngeal preparations, we determined that an insulin-dependent signal extrinsic to the pharyngeal system is involved in feeding adaptation. Hence, we suggest that reactive insulin signalling modulates both locomotory foraging and pharyngeal pumping as the animal adapts to the absence of food. We discuss this in the context of insulin signalling directing a shift in the sensitivity of neurotransmitter systems to regulate the worm's response to changes in food availability in the environment.

  18. Stress during Adolescence Alters Palatable Food Consumption in a Context-Dependent Manner.

    Directory of Open Access Journals (Sweden)

    Christine Handy

    Full Text Available Food consumption and preferences may be shaped by exposure to stressful environments during sensitive periods in development, and even small changes in consumption can have important effects on long term health. Adolescence is increasingly recognized as a sensitive period, in which adverse experiences can alter development, but the specific programming effects that may occur during adolescence remain incompletely understood. The current study seeks to explore the effects of stress during late adolescence on consumption of a palatable, high-fat, high-sugar food in adulthood-under basal conditions, as well following acute stress. Male Long-Evans rats were exposed to a regimen of variable stress for seven days in late adolescence (PND 45-51. During the stress regimen, stressed animals gained significantly less weight than control animals, but weight in adulthood was unaffected by adolescent stress. Palatable food consumption differed between experimental groups, and the direction of effect depended on context; stressed rats ate significantly more palatable food than controls upon first exposure, but ate less following an acute stressor. Leptin levels and exploratory behaviors did not differ between stressed and non-stressed groups, suggesting that other factors regulate preference for a palatable food. Altered food consumption following adolescent stress suggests that rats remain sensitive to stress during late adolescence, and that adult feeding behavior may be affected by previous adverse experiences. Such programming effects highlight adolescence as a period of plasticity, with the potential to shape long term food consumption patterns and preferences.

  19. Modeling spatial-temporal operations with context-dependent associative memories.

    Science.gov (United States)

    Mizraji, Eduardo; Lin, Juan

    2015-10-01

    We organize our behavior and store structured information with many procedures that require the coding of spatial and temporal order in specific neural modules. In the simplest cases, spatial and temporal relations are condensed in prepositions like "below" and "above", "behind" and "in front of", or "before" and "after", etc. Neural operators lie beneath these words, sharing some similarities with logical gates that compute spatial and temporal asymmetric relations. We show how these operators can be modeled by means of neural matrix memories acting on Kronecker tensor products of vectors. The complexity of these memories is further enhanced by their ability to store episodes unfolding in space and time. How does the brain scale up from the raw plasticity of contingent episodic memories to the apparent stable connectivity of large neural networks? We clarify this transition by analyzing a model that flexibly codes episodic spatial and temporal structures into contextual markers capable of linking different memory modules.

  20. Context-Dependent Victimization and Aggression: Differences between All-Girl and Mixed-Sex Schools

    Science.gov (United States)

    Velasquez, Ana Maria; Santo, Jonathan Bruce; Saldarriaga, Lina Maria; Lopez, Luz Stella; Bukowski, William M.

    2010-01-01

    Contextual differences in the association between different forms of aggressive behavior and victimization were studied with a sample of 197 boys and 149 girls from mixed-sex schools and in 336 girls from all-girl schools (M = 10.21 years of age) in two cities in Colombia. Results showed that boys generally engage in more physical than relational…

  1. The choice of Park & Ride Facilities: an analysis using a context-dependent hierarchical choice experiment

    NARCIS (Netherlands)

    Heijden, R.E.C.M. van der; Molin, E.J.E.; Timmermans, H.J.P.

    2004-01-01

    Park and Ride facilities have been proposed in several countries to alleviate the accessibility problems in cities. Despite growing accessibility problems, these facilities do not seem to attract the expected number of car drivers and are under-used. In an attempt to measure consumer evaluations of

  2. Context-dependent interpretation of the prognostic value of BRAF and KRAS mutations in colorectal cancer

    International Nuclear Information System (INIS)

    Popovici, Vlad; Budinska, Eva; Bosman, Fred T; Tejpar, Sabine; Roth, Arnaud D; Delorenzi, Mauro

    2013-01-01

    The mutation status of the BRAF and KRAS genes has been proposed as prognostic biomarker in colorectal cancer. Of them, only the BRAF V600E mutation has been validated independently as prognostic for overall survival and survival after relapse, while the prognostic value of KRAS mutation is still unclear. We investigated the prognostic value of BRAF and KRAS mutations in various contexts defined by stratifications of the patient population. We retrospectively analyzed a cohort of patients with stage II and III colorectal cancer from the PETACC-3 clinical trial (N = 1,423), by assessing the prognostic value of the BRAF and KRAS mutations in subpopulations defined by all possible combinations of the following clinico-pathological variables: T stage, N stage, tumor site, tumor grade and microsatellite instability status. In each such subpopulation, the prognostic value was assessed by log rank test for three endpoints: overall survival, relapse-free survival, and survival after relapse. The significance level was set to 0.01 for Bonferroni-adjusted p-values, and a second threshold for a trend towards statistical significance was set at 0.05 for unadjusted p-values. The significance of the interactions was tested by Wald test, with significance level of 0.05. In stage II-III colorectal cancer, BRAF mutation was confirmed a marker of poor survival only in subpopulations involving microsatellite stable and left-sided tumors, with higher effects than in the whole population. There was no evidence for prognostic value in microsatellite instable or right-sided tumor groups. We found that BRAF was also prognostic for relapse-free survival in some subpopulations. We found no evidence that KRAS mutations had prognostic value, although a trend was observed in some stratifications. We also show evidence of heterogeneity in survival of patients with BRAF V600E mutation. The BRAF mutation represents an additional risk factor only in some subpopulations of colorectal cancers, in others having limited prognostic value. However, in the subpopulations where it is prognostic, it represents a marker of much higher risk than previously considered. KRAS mutation status does not seem to represent a strong prognostic variable

  3. Context-Dependent Plastic Response during Egg-Laying in a Widespread Newt Species.

    Directory of Open Access Journals (Sweden)

    Zoltán Tóth

    Full Text Available Previous research on predator-induced phenotypic plasticity mostly focused on responses in morphology, developmental time and/or behaviour during early life stages, but the potential significance of anticipatory parental responses has been investigated less often. In this study I examined behavioural and maternal responses of gravid female smooth newts, Lissotriton vulgaris, in the presence of chemical cues originating from invertebrate predators, Acilius sulcatus water beetles and Aeshna cyanea dragonfly larvae. More specifically, I tested the extent of oviposition preference, plasticity in egg-wrapping behaviour and plasticity in egg size when females had the possibility to lay eggs at oviposition sites with and without predator cues during overnight trials. I found that individuals did not avoid laying eggs in the environment with predator cues; however, individuals that deposited eggs into both environments adjusted the size of the laid eggs to the perceived environment. Females deposited larger eggs earlier in the season but egg size decreased with time in the absence of predator cues, whereas individuals laid eggs of average size throughout the investigated reproductive period when such cues were present. Also, egg size was found to be positively related to hatching success. Individuals did not adjust their wrapping behaviour to the presence of predator cues, but females differed in the extent of egg-wrapping between ponds. Females' body mass and tail depth were also different between ponds, whereas their body size was positively associated with egg size. According to these results, female smooth newts have the potential to exhibit activational plasticity and invest differently into eggs depending on temporal and environmental factors. Such an anticipatory response may contribute to the success of this caudate species under a wide range of predator regimes at its natural breeding habitats.

  4. Pseudocontingencies and Choice Behavior in Probabilistic Environments with Context-Dependent Outcomes

    Science.gov (United States)

    Meiser, Thorsten; Rummel, Jan; Fleig, Hanna

    2018-01-01

    Pseudocontingencies are inferences about correlations in the environment that are formed on the basis of statistical regularities like skewed base rates or varying base rates across environmental contexts. Previous research has demonstrated that pseudocontingencies provide a pervasive mechanism of inductive inference in numerous social judgment…

  5. Maternal hormones meet environmental variability : Context-dependent effects of maternal hormones in avian egg yolks

    NARCIS (Netherlands)

    Hsu, Bin-Yan

    2016-01-01

    In the past few decades, maternal effects have been widely recognized as an important way through which mothers can modify offspring phenotypes above and over direct genetic effects. As a wide variety of animals are prenatal exposed to maternal hormones, accumulating evidences also suggest that

  6. Context-dependent planktivory: interacting effects of turbidity and predation risk on adaptive foraging

    Science.gov (United States)

    Pangle, Kevin L.; Malinich, Timothy D.; Bunnell, David B.; DeVries, Dennis R.; Ludsin, Stuart A.

    2012-01-01

    By shaping species interactions, adaptive phenotypic plasticity can profoundly influence ecosystems. Predicting such outcomes has proven difficult, however, owing in part to the dependence of plasticity on the environmental context. Of particular relevance are environmental factors that affect sensory performance in organisms in ways that alter the tradeoffs associated with adaptive phenotypic responses. We explored the influence of turbidity, which simultaneously and differentially affects the sensory performance of consumers at multiple trophic levels, on the indirect effect of a top predator (piscivorous fish) on a basal prey resource (zooplankton) that is mediated through changes in the plastic foraging behavior of an intermediate consumer (zooplanktivorous fish). We first generated theoretical predictions of the adaptive foraging response of a zooplanktivore across wide gradients of turbidity and predation risk by a piscivore. Our model predicted that predation risk can change the negative relationship between intermediate consumer foraging and turbidity into a humped-shaped (unimodal) one in which foraging is low in both clear and highly turbid conditions due to foraging-related risk and visual constraints, respectively. Consequently, the positive trait-mediated indirect effect (TMIE) of the top predator on the basal resource is predicted to peak at low turbidity and decline thereafter until it reaches an asymptote of zero at intermediate turbidity levels (when foraging equals that which is predicted when the top predator is absent). We used field observations and a laboratory experiment to test our model predictions. In support, we found humped-shaped relationships between planktivory and turbidity for several zooplanktivorous fishes from diverse freshwater ecosystems with predation risk. Further, our experiment demonstrated that predation risk reduced zooplanktivory by yellow perch (Perca flavescens) at a low turbidity, but had no effect on consumption at an intermediate turbidity. Together, our theoretical and empirical findings show how the environmental context can govern the strength of TMIEs by influencing consumer sensory performance and how these effects can become realized in nature over wide environmental gradients. Additionally, our hump-shaped foraging curve represents an important departure from the conventional view of turbidity's effect on planktivorous fishes, thus potentially requiring a reconceptualization of turbidity's impact on aquatic food-web interactions.

  7. Cutting edge: Dab2 is a FOXP3 target gene required for regulatory T cell function.

    Science.gov (United States)

    Jain, Nitya; Nguyen, Hai; Friedline, Randall H; Malhotra, Nidhi; Brehm, Michael; Koyanagi, Madoka; Bix, Mark; Cooper, Jonathan A; Chambers, Cynthia A; Kang, Joonsoo

    2009-10-01

    FOXP3-expressing regulatory T (Treg) cells are vital for maintaining peripheral T cell tolerance and homeostasis. The mechanisms by which FOXP3 target genes orchestrate context-dependent Treg cell function are largely unknown. In this study we show that in mouse peripheral lymphocytes the Drosophila Disabled-2 (Dab2) homolog, a gene that is involved in enhancing TGFbeta responses, is exclusively expressed in FOXP3+ regulatory T cells. Dab2 is a direct target of FOXP3, and regulatory T cells lacking DAB2 are functionally impaired in vitro and in vivo. However, not all aspects of Treg cell function are perturbed, and DAB2 appears to be dispensable for Treg cell function in maintaining naive T cell homeostasis.

  8. Disabled-2 is a FOXP3 target gene required for regulatory T cell function

    Science.gov (United States)

    Jain, N; Nguyen, H; Friedline, RH; Malhotra, N; Brehm, M; Koyonagi, M; Bix, M; Cooper, JA; Chambers, CA; Kang, J

    2010-01-01

    FOXP3 expressing regulatory T cells are vital for maintaining peripheral T cell tolerance and homeostasis. The mechanisms by which FOXP3 target genes orchestrate context-dependent Treg cell function are largely unknown. Here we show that in mouse peripheral lymphocytes, the Drosophila Disabled-2 (Dab2) homolog, a gene that is involved in enhancing TGFβ responses, is exclusively expressed in FOXP3+ regulatory T cells. Dab2 is a direct target of FOXP3 and regulatory T cells lacking DAB2 are functionally impaired in vitro and in vivo. However, not all aspects of Treg cell function are perturbed and DAB2 appears dispensable for Treg cell function in maintaining naïve T cell homeostasis. PMID:19767570

  9. Effects of red-backed salamanders on ecosystem functions.

    Directory of Open Access Journals (Sweden)

    Daniel J Hocking

    Full Text Available Ecosystems provide a vast array of services for human societies, but understanding how various organisms contribute to the functions that maintain these services remains an important ecological challenge. Predators can affect ecosystem functions through a combination of top-down trophic cascades and bottom-up effects on nutrient dynamics. As the most abundant vertebrate predator in many eastern US forests, woodland salamanders (Plethodon spp. likely affect ecosystems functions. We examined the effects of red-backed salamanders (Plethodon cinereus on a variety of forest ecosystem functions using a combined approach of large-scale salamander removals (314-m(2 plots and small-scale enclosures (2 m(2 where we explicitly manipulated salamander density (0, 0.5, 1, 2, 4 m(-2. In these experiments, we measured the rates of litter and wood decomposition, potential nitrogen mineralization and nitrification rates, acorn germination, and foliar insect damage on red oak seedlings. Across both experimental venues, we found no significant effect of red-backed salamanders on any of the ecosystem functions. We also found no effect of salamanders on intraguild predator abundance (carabid beetles, centipedes, spiders. Our study adds to the already conflicting evidence on effects of red-backed salamander and other amphibians on terrestrial ecosystem functions. It appears likely that the impact of terrestrial amphibians on ecosystem functions is context dependent. Future research would benefit from explicitly examining terrestrial amphibian effects on ecosystem functions under a variety of environmental conditions and in different forest types.

  10. The effect of imagination on stimulation: the functional specificity of efference copies in speech processing.

    Science.gov (United States)

    Tian, Xing; Poeppel, David

    2013-07-01

    The computational role of efference copies is widely appreciated in action and perception research, but their properties for speech processing remain murky. We tested the functional specificity of auditory efference copies using magnetoencephalography recordings in an unconventional pairing: We used a classical cognitive manipulation (mental imagery--to elicit internal simulation and estimation) with a well-established experimental paradigm (one shot repetition--to assess neuronal specificity). Participants performed tasks that differentially implicated internal prediction of sensory consequences (overt speaking, imagined speaking, and imagined hearing) and their modulatory effects on the perception of an auditory (syllable) probe were assessed. Remarkably, the neural responses to overt syllable probes vary systematically, both in terms of directionality (suppression, enhancement) and temporal dynamics (early, late), as a function of the preceding covert mental imagery adaptor. We show, in the context of a dual-pathway model, that internal simulation shapes perception in a context-dependent manner.

  11. Dissecting spatiotemporal patterns of functional diversity through the lens of Darwin's naturalization conundrum.

    Science.gov (United States)

    Campbell, Sara E; Mandrak, Nicholas E

    2017-06-01

    Darwin's naturalization conundrum describes the paradigm that community assembly is regulated by two opposing processes, environmental filtering and competitive interactions, which predict both similarity and distinctiveness of species to be important for establishment. Our goal is to use long-term, large-scale, and high-resolution temporal data to examine diversity patterns over time and assess whether environmental filtering or competition plays a larger role in regulating community assembly processes. We evaluated Darwin's naturalization conundrum and how functional diversity has changed in the Laurentian Great Lakes fish community from 1870 to 2010, which has experienced frequent introductions of non-native species and extirpations of native species. We analyzed how functional diversity has changed over time by decade from 1870 to 2010 at three spatial scales (regional, lake, and habitat) to account for potential noninteractions between species at the regional and lake level. We also determined which process, environmental filtering or competitive interactions, is more important in regulating community assembly and maintenance by comparing observed patterns to what we would expect in the absence of an ecological mechanism. With the exception of one community, all analyses show that functional diversity and species richness has increased over time and that environmental filtering regulates community assembly at the regional level. When examining functional diversity at the lake and habitat level, the regulating processes become more context dependent. This study is the first to examine diversity patterns and Darwin's conundrum by integrating long-term, large-scale, and high-resolution temporal data at multiple spatial scales. Our results confirm that Darwin's conundrum is highly context dependent.

  12. Functional Boxplots

    KAUST Repository

    Sun, Ying

    2011-01-01

    This article proposes an informative exploratory tool, the functional boxplot, for visualizing functional data, as well as its generalization, the enhanced functional boxplot. Based on the center outward ordering induced by band depth for functional data, the descriptive statistics of a functional boxplot are: the envelope of the 50% central region, the median curve, and the maximum non-outlying envelope. In addition, outliers can be detected in a functional boxplot by the 1.5 times the 50% central region empirical rule, analogous to the rule for classical boxplots. The construction of a functional boxplot is illustrated on a series of sea surface temperatures related to the El Niño phenomenon and its outlier detection performance is explored by simulations. As applications, the functional boxplot and enhanced functional boxplot are demonstrated on children growth data and spatio-temporal U.S. precipitation data for nine climatic regions, respectively. This article has supplementary material online. © 2011 American Statistical Association.

  13. Functionalized Calixpyrroles

    DEFF Research Database (Denmark)

    Vargas-Zúñiga, Gabriela; Sessler, Jonathan; Bähring, Steffen

    2016-01-01

    as the extraction and transport of anionic species and ion pairs including cesium halide and sulfate salts. It is divided into seven sections. The first section describes the synthetic methods employed to functionalized calix[4]pyrrole. The second section focuses on functionalized calix[4]pyrroles that display...... enhanced anion binding properties compared to the non-functionalized parent system, octamethylcalix[4]pyrrole. The use of functionalized calix[4]pyrroles containing a fluorescent group or functionalized calix[4]pyrroles as building blocks for the preparation of stimulus-responsive materials is discussed...... and the eventual development of therapeutics that function via the transport of anions across cell membranes, are discussed....

  14. Saccade-related activity in the prefrontal cortex: its role in eye movement control and cognitive functions

    Science.gov (United States)

    Funahashi, Shintaro

    2014-01-01

    Prefrontal neurons exhibit saccade-related activity and pre-saccadic memory-related activity often encodes the directions of forthcoming eye movements, in line with demonstrated prefrontal contribution to flexible control of voluntary eye movements. However, many prefrontal neurons exhibit post-saccadic activity that is initiated well after the initiation of eye movement. Although post-saccadic activity has been observed in the frontal eye field, this activity is thought to be a corollary discharge from oculomotor centers, because this activity shows no directional tuning and is observed whenever the monkeys perform eye movements regardless of goal-directed or not. However, prefrontal post-saccadic activities exhibit directional tunings similar as pre-saccadic activities and show context dependency, such that post-saccadic activity is observed only when monkeys perform goal-directed saccades. Context-dependency of prefrontal post-saccadic activity suggests that this activity is not a result of corollary signals from oculomotor centers, but contributes to other functions of the prefrontal cortex. One function might be the termination of memory-related activity after a behavioral response is done. This is supported by the observation that the termination of memory-related activity coincides with the initiation of post-saccadic activity in population analyses of prefrontal activities. The termination of memory-related activity at the end of the trial ensures that the subjects can prepare to receive new and updated information. Another function might be the monitoring of behavioral performance, since the termination of memory-related activity by post-saccadic activity could be associated with informing the correctness of the response and the termination of the trial. However, further studies are needed to examine the characteristics of saccade-related activities in the prefrontal cortex and their functions in eye movement control and a variety of cognitive functions

  15. A Functional Imaging Study of Self-Regulatory Capacities in Persons Who Stutter

    Science.gov (United States)

    Liu, Jie; Wang, Zhishun; Huo, Yuankai; Davidson, Stephanie M.; Klahr, Kristin; Herder, Carl L.; Sikora, Chamonix O.; Peterson, Bradley S.

    2014-01-01

    Developmental stuttering is a disorder of speech fluency with an unknown pathogenesis. The similarity of its phenotype and natural history with other childhood neuropsychiatric disorders of frontostriatal pathology suggests that stuttering may have a closely related pathogenesis. We investigated in this study the potential involvement of frontostriatal circuits in developmental stuttering. We collected functional magnetic resonance imaging data from 46 persons with stuttering and 52 fluent controls during performance of the Simon Spatial Incompatibility Task. We examined differences between the two groups of blood-oxygen-level-dependent activation associated with two neural processes, the resolution of cognitive conflict and the context-dependent adaptation to changes in conflict. Stuttering speakers and controls did not differ on behavioral performance on the task. In the presence of conflict-laden stimuli, however, stuttering speakers activated more strongly the cingulate cortex, left anterior prefrontal cortex, right medial frontal cortex, left supplementary motor area, right caudate nucleus, and left parietal cortex. The magnitude of activation in the anterior cingulate cortex correlated inversely in stuttering speakers with symptom severity. Stuttering speakers also showed blunted activation during context-dependent adaptation in the left dorsolateral prefrontal cortex, a brain region that mediates cross-temporal contingencies. Frontostriatal hyper-responsivity to conflict resembles prior findings in other disorders of frontostriatal pathology, and therefore likely represents a general mechanism supporting functional compensation for an underlying inefficiency of neural processing in these circuits. The reduced activation of dorsolateral prefrontal cortex likely represents the inadequate readiness of stuttering speakers to execute a sequence of motor responses. PMID:24587104

  16. A functional imaging study of self-regulatory capacities in persons who stutter.

    Directory of Open Access Journals (Sweden)

    Jie Liu

    Full Text Available Developmental stuttering is a disorder of speech fluency with an unknown pathogenesis. The similarity of its phenotype and natural history with other childhood neuropsychiatric disorders of frontostriatal pathology suggests that stuttering may have a closely related pathogenesis. We investigated in this study the potential involvement of frontostriatal circuits in developmental stuttering. We collected functional magnetic resonance imaging data from 46 persons with stuttering and 52 fluent controls during performance of the Simon Spatial Incompatibility Task. We examined differences between the two groups of blood-oxygen-level-dependent activation associated with two neural processes, the resolution of cognitive conflict and the context-dependent adaptation to changes in conflict. Stuttering speakers and controls did not differ on behavioral performance on the task. In the presence of conflict-laden stimuli, however, stuttering speakers activated more strongly the cingulate cortex, left anterior prefrontal cortex, right medial frontal cortex, left supplementary motor area, right caudate nucleus, and left parietal cortex. The magnitude of activation in the anterior cingulate cortex correlated inversely in stuttering speakers with symptom severity. Stuttering speakers also showed blunted activation during context-dependent adaptation in the left dorsolateral prefrontal cortex, a brain region that mediates cross-temporal contingencies. Frontostriatal hyper-responsivity to conflict resembles prior findings in other disorders of frontostriatal pathology, and therefore likely represents a general mechanism supporting functional compensation for an underlying inefficiency of neural processing in these circuits. The reduced activation of dorsolateral prefrontal cortex likely represents the inadequate readiness of stuttering speakers to execute a sequence of motor responses.

  17. ScanProsite: detection of PROSITE signature matches and ProRule-associated functional and structural residues in proteins.

    Science.gov (United States)

    de Castro, Edouard; Sigrist, Christian J A; Gattiker, Alexandre; Bulliard, Virginie; Langendijk-Genevaux, Petra S; Gasteiger, Elisabeth; Bairoch, Amos; Hulo, Nicolas

    2006-07-01

    ScanProsite--http://www.expasy.org/tools/scanprosite/--is a new and improved version of the web-based tool for detecting PROSITE signature matches in protein sequences. For a number of PROSITE profiles, the tool now makes use of ProRules--context-dependent annotation templates--to detect functional and structural intra-domain residues. The detection of those features enhances the power of function prediction based on profiles. Both user-defined sequences and sequences from the UniProt Knowledgebase can be matched against custom patterns, or against PROSITE signatures. To improve response times, matches of sequences from UniProtKB against PROSITE signatures are now retrieved from a pre-computed match database. Several output modes are available including simple text views and a rich mode providing an interactive match and feature viewer with a graphical representation of results.

  18. Entire functions

    CERN Document Server

    Markushevich, A I

    1966-01-01

    Entire Functions focuses on complex numbers and the algebraic operations on them and the basic principles of mathematical analysis.The book first elaborates on the concept of an entire function, including the natural generalization of the concept of a polynomial and power series. The text then takes a look at the maximum absolute value and the order of an entire function, as well as calculations for the coefficients of power series representing a given function, use of integrals, and complex numbers. The publication elaborates on the zeros of an entire function and the fundamen

  19. Modularity and Self-Organized Functional Architectures in the Brain

    Science.gov (United States)

    Iyer, Laxmi; Minai, Ali A.; Doboli, Simona; Brown, Vincent R.

    It is generally believed that cognition involves the self-organization of coherent dy- namic functional networks across several brain regions in response to incoming stimulus and internal modulation. These context-dependent networks arise continually from the spatiotemporally multi-scale structural substrate of the brain configured by evolution, development and previous experience, persisting for 100-200 ms and generating re- sponses such as imagery, recall and motor action. In the current paper, we show that a system of interacting modular attractor networks can use a selective mechanism for assembling functional networks from the modular substrate. We use the approach to develop a model of idea-generation in the brain. Ideas are modeled as combinations of concepts organized in a recurrent network that reflects previous associations between them. The dynamics of this network, resulting in the transient co-activation of concept groups, is seen as a search through the space of ideas, and attractor dynamics is used to "shape" this search. The process is required to encompass both rapid retrieval of old ideas in familiar contexts and efficient search for novel ones in unfamiliar situations (or during brainstorming). The inclusion of an adaptive modulatory mechanism allows the network to balance the competing requirements of exploiting previous learning and exploring new possibilities as needed in different contexts.

  20. Functional analysis

    CERN Document Server

    Kantorovich, L V

    1982-01-01

    Functional Analysis examines trends in functional analysis as a mathematical discipline and the ever-increasing role played by its techniques in applications. The theory of topological vector spaces is emphasized, along with the applications of functional analysis to applied analysis. Some topics of functional analysis connected with applications to mathematical economics and control theory are also discussed. Comprised of 18 chapters, this book begins with an introduction to the elements of the theory of topological spaces, the theory of metric spaces, and the theory of abstract measure space

  1. Functionalized amphipols

    DEFF Research Database (Denmark)

    Della Pia, Eduardo Antonio; Hansen, Randi Westh; Zoonens, Manuela

    2014-01-01

    Amphipols are amphipathic polymers that stabilize membrane proteins isolated from their native membrane. They have been functionalized with various chemical groups in the past years for protein labeling and protein immobilization. This large toolbox of functionalized amphipols combined...... with their interesting physico-chemical properties give opportunities to selectively add multiple functionalities to membrane proteins and to tune them according to the needs. This unique combination of properties makes them one of the most versatile strategies available today for exploiting membrane proteins onto...... surfaces for various applications in synthetic biology. This review summarizes the properties of functionalized amphipols suitable for synthetic biology approaches....

  2. A flexible ontology for inference of emergent whole cell function from relationships between subcellular processes.

    Science.gov (United States)

    Hansen, Jens; Meretzky, David; Woldesenbet, Simeneh; Stolovitzky, Gustavo; Iyengar, Ravi

    2017-12-18

    Whole cell responses arise from coordinated interactions between diverse human gene products functioning within various pathways underlying sub-cellular processes (SCP). Lower level SCPs interact to form higher level SCPs, often in a context specific manner to give rise to whole cell function. We sought to determine if capturing such relationships enables us to describe the emergence of whole cell functions from interacting SCPs. We developed the Molecular Biology of the Cell Ontology based on standard cell biology and biochemistry textbooks and review articles. Currently, our ontology contains 5,384 genes, 753 SCPs and 19,180 expertly curated gene-SCP associations. Our algorithm to populate the SCPs with genes enables extension of the ontology on demand and the adaption of the ontology to the continuously growing cell biological knowledge. Since whole cell responses most often arise from the coordinated activity of multiple SCPs, we developed a dynamic enrichment algorithm that flexibly predicts SCP-SCP relationships beyond the current taxonomy. This algorithm enables us to identify interactions between SCPs as a basis for higher order function in a context dependent manner, allowing us to provide a detailed description of how SCPs together can give rise to whole cell functions. We conclude that this ontology can, from omics data sets, enable the development of detailed SCP networks for predictive modeling of emergent whole cell functions.

  3. Developmental plasticity of spatial hearing following asymmetric hearing loss: context-dependent cue integration and its clinical implications

    Directory of Open Access Journals (Sweden)

    Peter eKeating

    2013-12-01

    Full Text Available Under normal hearing conditions, comparisons of the sounds reaching each ear are critical for accurate sound localization. Asymmetric hearing loss should therefore degrade spatial hearing and has become an important experimental tool for probing the plasticity of the auditory system, both during development and adulthood. In clinical populations, hearing loss affecting one ear more than the other is commonly associated with otitis media with effusion, a disorder experienced by approximately 80% of children before the age of two. Asymmetric hearing may also arise in other clinical situations, such as after unilateral cochlear implantation. Here, we consider the role played by spatial cue integration in sound localization under normal acoustical conditions. We then review evidence for adaptive changes in spatial hearing following a developmental hearing loss in one ear, and argue that adaptation may be achieved either by learning a new relationship between the altered cues and directions in space or by changing the way different cues are integrated in the brain. We next consider developmental plasticity as a source of vulnerability, describing maladaptive effects of asymmetric hearing loss that persist even when normal hearing is provided. We also examine the extent to which the consequences of asymmetric hearing loss depend upon its timing and duration. Although much of the experimental literature has focused on the effects of a stable unilateral hearing loss, some of the most common hearing impairments experienced by children tend to fluctuate over time. We therefore argue that there is a need to bridge this gap by investigating the effects of recurring hearing loss during development, and outline recent steps in this direction. We conclude by arguing that this work points toward a more nuanced view of developmental plasticity, in which plasticity may be selectively expressed in response to specific sensory contexts, and consider the clinical implications of this.

  4. Mutation Rate, Spectrum, Topology, and Context-Dependency in the DNA Mismatch Repair-Deficient Pseudomonas fluorescens ATCC948

    OpenAIRE

    Long, Hongan; Sung, Way; Miller, Samuel F.; Ackerman, Matthew S.; Doak, Thomas G.; Lynch, Michael

    2014-01-01

    High levels of genetic diversity exist among natural isolates of the bacterium Pseudomonas fluorescens, and are especially elevated around the replication terminus of the genome, where strain-specific genes are found. In an effort to understand the role of genetic variation in the evolution of Pseudomonas, we analyzed 31,106 base substitutions from 45 mutation accumulation lines of P. fluorescens ATCC948, naturally deficient for mismatch repair, yielding a base-substitution mutation rate of 2...

  5. Agonistic interactions between the honeybee (Apis mellifera ligustica and the European wasp (Vespula germanica reveal context-dependent defense strategies.

    Directory of Open Access Journals (Sweden)

    Michelina Pusceddu

    Full Text Available Predator-prey relationships between sympatric species allow the evolution of defense behaviors, such as honeybee colonies defending their nests against predatory wasps. We investigated the predator-prey relationship between the honeybee (Apis mellifera ligustica and the European wasp (Vespula germanica by evaluating the effectiveness of attack and defense behaviors, which have coevolved in these sympatric species, as well as the actual damage and disturbance caused to the colonies under attack. Attack and defense behaviors were recorded in front of the hive to observe attacks at the hive entrance (68 attacks in 279 h and at ground level on isolated and weakened honeybees close to the hive (465 attacks in 32 h. We found that V. germanica attacked the hive entrance infrequently due to the low success rate of this strategy and instead preferred a specialized attack method targeting adult honeybees at ground level, demonstrating opportunistic scavenger behavior. Individual honeybees usually responded effectively to an attack by recruiting an average of two nestmates, causing the wasp to flee, whereas collective balling behavior was only observed on four occasions. V. germanica does not appear to disrupt the foraging activity of the colonies under attack. We found that agonistic events supported by other nestmates were typically the most intense ones, involving physical combat and prolonged attacks at the entrance to the hive. These observations support the hypothesis that A. mellifera ligustica can adapt its behavior to match the severity of the threat and the context of the attack.

  6. Agonistic interactions between the honeybee (Apis mellifera ligustica) and the European wasp (Vespula germanica) reveal context-dependent defense strategies.

    Science.gov (United States)

    Pusceddu, Michelina; Floris, Ignazio; Buffa, Franco; Salaris, Emanuele; Satta, Alberto

    2017-01-01

    Predator-prey relationships between sympatric species allow the evolution of defense behaviors, such as honeybee colonies defending their nests against predatory wasps. We investigated the predator-prey relationship between the honeybee (Apis mellifera ligustica) and the European wasp (Vespula germanica) by evaluating the effectiveness of attack and defense behaviors, which have coevolved in these sympatric species, as well as the actual damage and disturbance caused to the colonies under attack. Attack and defense behaviors were recorded in front of the hive to observe attacks at the hive entrance (68 attacks in 279 h) and at ground level on isolated and weakened honeybees close to the hive (465 attacks in 32 h). We found that V. germanica attacked the hive entrance infrequently due to the low success rate of this strategy and instead preferred a specialized attack method targeting adult honeybees at ground level, demonstrating opportunistic scavenger behavior. Individual honeybees usually responded effectively to an attack by recruiting an average of two nestmates, causing the wasp to flee, whereas collective balling behavior was only observed on four occasions. V. germanica does not appear to disrupt the foraging activity of the colonies under attack. We found that agonistic events supported by other nestmates were typically the most intense ones, involving physical combat and prolonged attacks at the entrance to the hive. These observations support the hypothesis that A. mellifera ligustica can adapt its behavior to match the severity of the threat and the context of the attack.

  7. Stabilization of the genome of the mismatch repair deficient Mycobacterium tuberculosis by context-dependent codon choice

    OpenAIRE

    Wanner, Roger M; Güthlein, Carolin; Springer, Burkhard; Böttger, Erik C; Ackermann, Martin

    2008-01-01

    Abstract Background The rate at which a stretch of DNA mutates is determined by the cellular systems for DNA replication and repair, and by the nucleotide sequence of the stretch itself. One sequence feature with a particularly strong influence on the mutation rate are nucleotide repeats. Some microbial pathogens use nucleotide repeats in their genome to stochastically vary phenotypic traits and thereby evade host defense. However, such unstable sequences also come at a cost, as mutations are...

  8. Context-Dependence, Visibility, and Prediction Using State and Trait Individual Differences as Moderators of ESP in a Ganzfeld Environment

    Directory of Open Access Journals (Sweden)

    José Miguel Pérez-Navarro

    2012-11-01

    Full Text Available In this paper we present a method for participant classification, based on trait and state, in the experimental evaluation of ESP (extrasensory perception. We conducted three Ganzfeld experiments with a sample of 237 participants. In experiment I (N = 60 twenty participants ranked the target stimulus in the first position, achieving a non-significant rate of correct guesses of 33.3% (z = 1.48, p = .07, one tailed. In experiment II (N = 90 only 26.6% of the participants’ guesses were correct (z = .35, p = .36, one tailed. Weighting trials in the second experiment on the basis of the most successful predictors of the participants’ performance in the first experiment increased the rate of correct guesses from 26.6% to 36.4%. Results in a confirmatory experiment (N = 87 were not significant (32.7%, z = 1.32, p = .09, one tailed. However, overall results in this study were consistent with the effects sizes data reported in previous meta-analyses.

  9. On the context-dependent nature of the contribution of the ventral premotor cortex to speech perception

    Science.gov (United States)

    Tremblay, Pascale; Small, Steven L.

    2011-01-01

    What is the nature of the interface between speech perception and production, where auditory and motor representations converge? One set of explanations suggests that during perception, the motor circuits involved in producing a perceived action are in some way enacting the action without actually causing movement (covert simulation) or sending along the motor information to be used to predict its sensory consequences (i.e., efference copy). Other accounts either reject entirely the involvement of motor representations in perception, or explain their role as being more supportive than integral, and not employing the identical circuits used in production. Using fMRI, we investigated whether there are brain regions that are conjointly active for both speech perception and production, and whether these regions are sensitive to articulatory (syllabic) complexity during both processes, which is predicted by a covert simulation account. A group of healthy young adults (1) observed a female speaker produce a set of familiar words (perception), and (2) observed and then repeated the words (production). There were two types of words, varying in articulatory complexity, as measured by the presence or absence of consonant clusters. The simple words contained no consonant cluster (e.g. “palace”), while the complex words contained one to three consonant clusters (e.g. “planet”). Results indicate that the left ventral premotor cortex (PMv) was significantly active during speech perception and speech production but that activation in this region was scaled to articulatory complexity only during speech production, revealing an incompletely specified efferent motor signal during speech perception. The right planum temporal (PT) was also active during speech perception and speech production, and activation in this region was scaled to articulatory complexity during both production and perception. These findings are discussed in the context of current theories theory of speech perception, with particular attention to accounts that include an explanatory role for mirror neurons. PMID:21664275

  10. Context-dependence of long-term responses of terrestrial gastropod populations to large-scale disturbance.

    Science.gov (United States)

    Christopher P. Bloch; Michael R. Willi

    2006-01-01

    Large-scale natural disturbances, such as hurricanes, can have profound effects on animal populations. Nonetheless, generalizations about the effects of disturbance are elusive, and few studies consider long-term responses of a single population or community to multiple large-scale disturbance events. In the last 20 y, twomajor hurricanes (Hugo and Georges) have struck...

  11. Random neuronal ensembles can inherently do context dependent coarse conjunctive encoding of input stimulus without any specific training.

    Science.gov (United States)

    George, Jude Baby; Abraham, Grace Mathew; Rashid, Zubin; Amrutur, Bharadwaj; Sikdar, Sujit Kumar

    2018-01-23

    Conjunctive encoding of inputs has been hypothesized to be a key feature in the computational capabilities of the brain. This has been inferred based on behavioral studies and electrophysiological recording from animals. In this report, we show that random neuronal ensembles grown on multi-electrode array perform a coarse-conjunctive encoding for a sequence of inputs with the first input setting the context. Such an encoding scheme creates similar yet unique population codes at the output of the ensemble, for related input sequences, which can then be decoded via a simple perceptron and hence a single STDP neuron layer. The random neuronal ensembles allow for pattern generalization and novel sequence classification without needing any specific learning or training of the ensemble. Such a representation of the inputs as population codes of neuronal ensemble outputs, has inherent redundancy and is suitable for further decoding via even probabilistic/random connections to subsequent neuronal layers. We reproduce this behavior in a mathematical model to show that a random neuronal network with a mix of excitatory and inhibitory neurons and sufficient connectivity creates similar coarse-conjunctive encoding of input sequences.

  12. Context-dependent interactive effects of non-lethal predation on larvae impact adult longevity and body composition

    Science.gov (United States)

    Kandregula, Samyuktha Rao; Quader, Suhel; Juliano, Steven A.

    2018-01-01

    Predation impacts development, behavior and morphology of prey species thereby shaping their abundances, distribution and community structure. Non-lethal threat of predation, specifically, can have a strong influence on prey lifehistory characteristics. While investigations often focus on the impact of predation threat on prey in isolation, tests of its interactive effects with food availability and resource competition on prey survival and fitness can improve understanding of costs, benefits and trade-offs of anti-predator strategies. This study, involving Aedes aegypti mosquitoes as a model organism, investigates both simple and interactive effects of predation threat during the larval stage on survival, size at and time to maturity, stored teneral reserves of glycogen, protein and lipid in adults, and adult longevity. Our results show that development times of mosquito larvae were increased (by 14.84% in males and by 97.63% in females), and size of eclosing adults decreased (by 62.30% in males and by 58.33% in females) when exposed to lowered nutrition and elevated intraspecific competition, but that predation had no detectable effect on these simple traits. Teneral reserves of glycogen, protein and lipid and adult longevity were positively correlated with adult body size. Non-lethal predation threat had significant interactive effects with nutrition and larval competition on teneral reserves in males and adult longevity in males and females. The sexes responded differently to conditions encountered as larvae, with the larval environment affecting development and adult characteristics more acutely for females than for males. The outcome of this study shows how threat of predation on juveniles can have long-lasting effects on adults that are likely to impact mosquito population dynamics and that may impact disease transmission. PMID:29401513

  13. Is the relation between alexithymia and aggression context-dependent? Impact of group membership and belief similarity

    NARCIS (Netherlands)

    Konrath, S.; Novin, S.; Li, T.

    2012-01-01

    Previous research finds positive relationships between alexithymia and aggression. This study examined potential interpersonal factors that might elicit aggressiveness among people with high levels of alexithymia. College student participants completed the Toronto Alexithymia Scale online prior to

  14. Ad-hoc and context-dependent adjustments of selective attention in conflict control: an ERP study with visual probes.

    Science.gov (United States)

    Nigbur, R; Schneider, J; Sommer, W; Dimigen, O; Stürmer, B

    2015-02-15

    Cognitive conflict control in flanker tasks has often been described using the zoom-lens metaphor of selective attention. However, whether and how selective attention - in terms of suppression and enhancement - operates in this context has remained unclear. To examine the dynamic interplay of selective attention and cognitive control we used electrophysiological measures and presented task-irrelevant visual probe stimuli at foveal, parafoveal, and peripheral display positions. Target-flanker congruency varied either randomly from trial to trial (mixed-block) or block-wise (fixed-block) in order to induce reactive versus proactive control modes, respectively. Three EEG measures were used to capture ad-hoc adjustments within trials as well as effects of context-based predictions: the N1 component of the visual evoked potential (VEP) to probes, the VEP to targets, and the conflict-related midfrontal N2 component. Results from probe-VEPs indicate that enhanced processing of the foveal target rather than suppression of the peripheral flankers supports interference control. In incongruent mixed-block trials VEPs were larger to probes near the targets. In the fixed-blocks probe-VEPs were not modulated, but contrary to the mixed-block the preceding target-related VEP was affected by congruency. Results of the control-related N2 reveal largest amplitudes in the unpredictable context, which did not differentiate for stimulus and response incongruency. In contrast, in the predictable context, N2 amplitudes were reduced overall and differentiated between stimulus and response incongruency. Taken together these results imply that predictability alters interference control by a reconfiguration of stimulus processing. During unpredictable sequences participants adjust their attentional focus dynamically on a trial-by-trial basis as reflected in congruency-dependent probe-VEP-modulation. This reactive control mode also elicits larger N2 amplitudes. In contrast, when task demands are predictable, participants focus selective attention earlier as reflected in the target-related VEPs. This proactive control mode leads to smaller N2 amplitudes and absent probe effects. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Vocal foragers and silent crowds : context-dependent vocal variation in Northeast Atlantic long-finned pilot whales

    NARCIS (Netherlands)

    Visser, F.; Kok, A.C.M.; Oudejans, M.G.; Scott-Hayward, L.A.S.; DeRuiter, S.L.; Alves, A.C.; Antunes, R.N.; Isojunno, S.; Pierce, G.J.; Slabbekoorn, H.; Huisman, J.; Miller, P.J.O.

    2017-01-01

    Vocalisations form a key component of the social interactions and foraging behaviour of toothed whales. We investigated changes in calling and echolocation behaviour of long-finned pilot whales between foraging and non-foraging periods, by combining acoustic recordings and diving depth data from

  16. Writing of H3K4Me3 overcomes epigenetic silencing in a sustained but context-dependent manner

    NARCIS (Netherlands)

    Cano-Rodriguez, David; Gjaltema, Rutger A. F.; Jilderda, Laura J.; Jellema, Pytrick; Dokter-Fokkens, Jelleke; Ruiters, Marcel H. J.; Rots, Marianne G.

    Histone modifications reflect gene activity, but the relationship between cause and consequence of transcriptional control is heavily debated. Recent developments in rewriting local histone codes of endogenous genes elucidated instructiveness of certain marks in regulating gene expression.

  17. Highchair Philosophers: The Impact of Seating Context-Dependent Exploration on Children's Naming Biases

    Science.gov (United States)

    Perry, Lynn K.; Samuelson, Larissa K.; Burdinie, Johanna B.

    2014-01-01

    We examine developmental interactions between context, exploration, and word learning. Infants show an understanding of how nonsolid substances are categorized that does not reliably transfer to learning how these categories are named in laboratory tasks. We argue that what infants learn about naming nonsolid substances is contextually bound--most…

  18. A comparative study of Caribbean return migration from Britain and France: towards a context-dependent explanation.

    Science.gov (United States)

    Byron, M; Condon, S

    1996-01-01

    "The currently dominant element in the labour migration from the Caribbean to Britain and France is a return flow of migrants. This paper focuses on the migrations from the Commonwealth and the French Caribbean to Britain and France respectively. While these migrations are historically similar in origin, subsequent differences in the colonial and immigration policies of Britain and France have resulted in divergent migration trends and experiences. New sources of data are drawn on in this comparative study of return migration to the Caribbean, providing up-to-date information on the size and demographic characteristics of the returnee populations. Equally important to this study is the section of the migrant population who are likely to remain in Europe. The authors argue that a comprehensive model of labour migration would need to incorporate the non-return situation in its dynamic entirety." excerpt

  19. The role of consolidation in learning context-dependent phonotactic patterns in speech and digital sequence production.

    Science.gov (United States)

    Anderson, Nathaniel D; Dell, Gary S

    2018-04-03

    Speakers implicitly learn novel phonotactic patterns by producing strings of syllables. The learning is revealed in their speech errors. First-order patterns, such as "/f/ must be a syllable onset," can be distinguished from contingent, or second-order, patterns, such as "/f/ must be an onset if the vowel is /a/, but a coda if the vowel is /o/." A metaanalysis of 19 experiments clearly demonstrated that first-order patterns affect speech errors to a very great extent in a single experimental session, but second-order vowel-contingent patterns only affect errors on the second day of testing, suggesting the need for a consolidation period. Two experiments tested an analogue to these studies involving sequences of button pushes, with fingers as "consonants" and thumbs as "vowels." The button-push errors revealed two of the key speech-error findings: first-order patterns are learned quickly, but second-order thumb-contingent patterns are only strongly revealed in the errors on the second day of testing. The influence of computational complexity on the implicit learning of phonotactic patterns in speech production may be a general feature of sequence production.

  20. Selector genes display tumor cooperation and inhibition in Drosophila epithelium in a developmental context-dependent manner

    OpenAIRE

    Ram Prakash Gupta; Anjali Bajpai; Pradip Sinha

    2017-01-01

    During animal development, selector genes determine identities of body segments and those of individual organs. Selector genes are also misexpressed in cancers, although their contributions to tumor progression per se remain poorly understood. Using a model of cooperative tumorigenesis, we show that gain of selector genes results in tumor cooperation, but in only select developmental domains of the wing, haltere and eye-antennal imaginal discs of Drosophila larva. Thus, the field selector, Ey...

  1. Selector genes display tumor cooperation and inhibition in Drosophila epithelium in a developmental context-dependent manner

    OpenAIRE

    Gupta, Ram Prakash; Bajpai, Anjali; Sinha, Pradip

    2017-01-01

    ABSTRACT During animal development, selector genes determine identities of body segments and those of individual organs. Selector genes are also misexpressed in cancers, although their contributions to tumor progression per se remain poorly understood. Using a model of cooperative tumorigenesis, we show that gain of selector genes results in tumor cooperation, but in only select developmental domains of the wing, haltere and eye-antennal imaginal discs of Drosophila larva. Thus, the field sel...

  2. Selector genes display tumor cooperation and inhibition in Drosophila epithelium in a developmental context-dependent manner

    Directory of Open Access Journals (Sweden)

    Ram Prakash Gupta

    2017-11-01

    Full Text Available During animal development, selector genes determine identities of body segments and those of individual organs. Selector genes are also misexpressed in cancers, although their contributions to tumor progression per se remain poorly understood. Using a model of cooperative tumorigenesis, we show that gain of selector genes results in tumor cooperation, but in only select developmental domains of the wing, haltere and eye-antennal imaginal discs of Drosophila larva. Thus, the field selector, Eyeless (Ey, and the segment selector, Ultrabithorax (Ubx, readily cooperate to bring about neoplastic transformation of cells displaying somatic loss of the tumor suppressor, Lgl, but in only those developmental domains that express the homeo-box protein, Homothorax (Hth, and/or the Zinc-finger protein, Teashirt (Tsh. In non-Hth/Tsh-expressing domains of these imaginal discs, however, gain of Ey in lgl− somatic clones induces neoplastic transformation in the distal wing disc and haltere, but not in the eye imaginal disc. Likewise, gain of Ubx in lgl− somatic clones induces transformation in the eye imaginal disc but not in its endogenous domain, namely, the haltere imaginal disc. Our results reveal that selector genes could behave as tumor drivers or inhibitors depending on the tissue contexts of their gains.

  3. Context-dependent effects of cold stress on behavioral, physiological, and life-history traits of the red flour beetle.

    Science.gov (United States)

    Scharf, Inon; Wertheimer, Keren-Or; Xin, Joy Lim; Gilad, Tomer; Goldenberg, Inna; Subach, Aziz

    2017-06-20

    Animals are exposed in nature to a variety of stressors. While stress is generally harmful, mild stress can also be beneficial and contribute to reproduction and survival. We studied the effect of five cold shock events versus a single cold shock and a control group, representing three levels of stress (harsh, mild, and no stress), on behavioral, physiological, and life-history traits of the red flour beetle (Tribolium castaneum, Herbst 1797). Beetles exposed to harsh cold stress were less active than a control group: they moved less and failed more frequently to detect a food patch. Their probability to mate was also lower. Beetle pairs exposed to harsh cold stress frequently failed to reproduce at all, and if reproducing, females laid fewer eggs, which were, as larvae in mid-development, smaller than those in the control group. However, harsh cold stress led to improved female starvation tolerance, probably due to enhanced lipid accumulation. Harsh cold shock also improved tolerance to an additional cold shock compared to the control. Finally, a single cold shock event negatively affected fewer measured response variables than the harsh cold stress, but also enhanced neither starvation tolerance nor tolerance to an additional cold shock. The consequences of a harsher cold stress are thus not solely detrimental but might even enhance survival under stressful conditions. Under benign conditions, nevertheless, harsh stress impedes beetle performance. The harsh stress probably shifted the balance point of the survival-reproduction trade-off, a shift that did not take place following exposure to mild stress. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  4. Validated context-dependent associations of coronary heart disease risk with genotype variation in the chromosome 9p21 region

    DEFF Research Database (Denmark)

    Lusk, Christine M; Dyson, Greg; Clark, Andrew G

    2014-01-01

    variations marking the 9p21 region for explaining variation in CHD risk? We analyzed a sample of 7,589 (3,869 females and 3,720 males) European American participants of the Atherosclerosis Risk in Communities study. We confirmed CHD-SNP genotype associations for two 9p21 region marker SNPs previously......Markers of the chromosome 9p21 region are regarded as the strongest and most reliably significant genome-wide association study (GWAS) signals for Coronary heart disease (CHD) risk; this was recently confirmed by the CARDIoGRAMplusC4D Consortium meta-analysis. However, while these associations...... are significant at the population level, they may not be clinically relevant predictors of risk for all individuals. We describe here the results of a study designed to address the question: What is the contribution of context defined by traditional risk factors in determining the utility of DNA sequence...

  5. The Context-Dependency of the Experience of Auditory Succession and Prospects for Embodying Philosophical Models of Temporal Experience

    OpenAIRE

    Maria Kon

    2015-01-01

    Recent philosophical work on temporal experience offers generic models that are often assumed to apply to all sensory modalities. I show that the models serve as broad frameworks in which different aspects of cognitive science can be slotted and, thus, are beneficial to furthering research programs in embodied music cognition. Here I discuss a particular feature of temporal experience that plays a key role in such philosophical work: a distinction between the experience of succession and the ...

  6. The hide-and-seek of retrospective revaluation: recovery from blocking is context dependent in human causal learning

    NARCIS (Netherlands)

    Boddez, Y.; Baeyens, F.; Hermans, D.; Beckers, T.

    2011-01-01

    In a typical blocking procedure, pairings of a compound consisting of 2 stimuli, A and X, with the outcome are preceded by pairings of only A with the outcome (i.e., A+ then AX+). This procedure is known to diminish responding to the target cue (X) relative to a control group that does not receive

  7. Mutualists or parasites? Context-dependent influence of symbiotic fly larvae on carnivorous investment in the Albany pitcher plant.

    Science.gov (United States)

    Lymbery, Samuel J; Didham, Raphael K; Hopper, Stephen D; Simmons, Leigh W

    2016-11-01

    Carnivorous plants allocate more resources to carnivorous structures under nutrient-limited conditions, and relative investment can also be influenced by animals (infauna) that live in association with these plants and feed on their prey. We investigated these effects within a population of the pitcher plant Cephalotus follicularis containing varying densities of larvae of the fly Badisis ambulans . For plants with a relatively high proportion of adult pitchers, increasing larval density was associated with lower relative leaf allocation to new pitcher buds. For plants with relatively few adult pitchers, however, there was greater relative leaf allocation to pitcher buds with increasing larval density. In a field experiment, there was no significant effect of experimental larval presence or absence on the change in carbon-to-nitrogen (C/N) ratio of plants. Although the direction of the correlation between B. ambulans larvae and relative investment in carnivorous and non-carnivorous structures depends on the relative number of mature structures, whether the larvae enhance or reduce nutrient stress under different conditions remains unclear. The change in C/N was, however, less variable for pitchers that contained larvae, suggesting a stabilizing effect. Eighteen of 52 experimental pitchers were damaged by an unknown species, causing the pitcher fluid to drain. These pitchers were significantly more likely to survive if they contained larvae. These results suggest that the relationship between infauna and host varies with the initial resource status and environmental context of the host plant.

  8. Cognitive Function

    Science.gov (United States)

    Because chemicals can adversely affect cognitive function in humans, considerable effort has been made to characterize their effects using animal models. Information from such models will be necessary to: evaluate whether chemicals identified as potentially neurotoxic by screenin...

  9. Functional unparsing

    DEFF Research Database (Denmark)

    Danvy, Olivier

    2000-01-01

    A string-formatting function such as printf in C seemingly requires dependent types, because its control string determines the rest of its arguments. Examples: formula here We show how changing the representation of the control string makes it possible to program printf in ML (which does not allow...... dependent types). The result is well typed and perceptibly more efficient than the corresponding library functions in Standard ML of New Jersey and in Caml....

  10. Functional Unparsing

    DEFF Research Database (Denmark)

    Danvy, Olivier

    1998-01-01

    A string-formatting function such as printf in C seemingly requires dependent types, because its control string determines the rest of its arguments. We show how changing the representation of the control string makes it possible to program printf in ML (which does not allow dependent types......). The result is well typed and perceptibly more efficient than the corresponding library functions in Standard ML of New Jersey and in Caml....

  11. Insights into Hox protein function from a large scale combinatorial analysis of protein domains.

    Science.gov (United States)

    Merabet, Samir; Litim-Mecheri, Isma; Karlsson, Daniel; Dixit, Richa; Saadaoui, Mehdi; Monier, Bruno; Brun, Christine; Thor, Stefan; Vijayraghavan, K; Perrin, Laurent; Pradel, Jacques; Graba, Yacine

    2011-10-01

    Protein function is encoded within protein sequence and protein domains. However, how protein domains cooperate within a protein to modulate overall activity and how this impacts functional diversification at the molecular and organism levels remains largely unaddressed. Focusing on three domains of the central class Drosophila Hox transcription factor AbdominalA (AbdA), we used combinatorial domain mutations and most known AbdA developmental functions as biological readouts to investigate how protein domains collectively shape protein activity. The results uncover redundancy, interactivity, and multifunctionality of protein domains as salient features underlying overall AbdA protein activity, providing means to apprehend functional diversity and accounting for the robustness of Hox-controlled developmental programs. Importantly, the results highlight context-dependency in protein domain usage and interaction, allowing major modifications in domains to be tolerated without general functional loss. The non-pleoitropic effect of domain mutation suggests that protein modification may contribute more broadly to molecular changes underlying morphological diversification during evolution, so far thought to rely largely on modification in gene cis-regulatory sequences.

  12. Insights into Hox protein function from a large scale combinatorial analysis of protein domains.

    Directory of Open Access Journals (Sweden)

    Samir Merabet

    2011-10-01

    Full Text Available Protein function is encoded within protein sequence and protein domains. However, how protein domains cooperate within a protein to modulate overall activity and how this impacts functional diversification at the molecular and organism levels remains largely unaddressed. Focusing on three domains of the central class Drosophila Hox transcription factor AbdominalA (AbdA, we used combinatorial domain mutations and most known AbdA developmental functions as biological readouts to investigate how protein domains collectively shape protein activity. The results uncover redundancy, interactivity, and multifunctionality of protein domains as salient features underlying overall AbdA protein activity, providing means to apprehend functional diversity and accounting for the robustness of Hox-controlled developmental programs. Importantly, the results highlight context-dependency in protein domain usage and interaction, allowing major modifications in domains to be tolerated without general functional loss. The non-pleoitropic effect of domain mutation suggests that protein modification may contribute more broadly to molecular changes underlying morphological diversification during evolution, so far thought to rely largely on modification in gene cis-regulatory sequences.

  13. interval functions

    Directory of Open Access Journals (Sweden)

    J. A. Chatfield

    1978-01-01

    Full Text Available Suppose N is a Banach space of norm |•| and R is the set of real numbers. All integrals used are of the subdivision-refinement type. The main theorem [Theorem 3] gives a representation of TH where H is a function from R×R to N such that H(p+,p+, H(p,p+, H(p−,p−, and H(p−,p each exist for each p and T is a bounded linear operator on the space of all such functions H. In particular we show that TH=(I∫abfHdα+∑i=1∞[H(xi−1,xi−1+−H(xi−1+,xi−1+]β(xi−1+∑i=1∞[H(xi−,xi−H(xi−,xi−]Θ(xi−1,xiwhere each of α, β, and Θ depend only on T, α is of bounded variation, β and Θ are 0 except at a countable number of points, fH is a function from R to N depending on H and {xi}i=1∞ denotes the points P in [a,b]. for which [H(p,p+−H(p+,p+]≠0 or [H(p−,p−H(p−,p−]≠0. We also define an interior interval function integral and give a relationship between it and the standard interval function integral.

  14. Bessel functions

    CERN Document Server

    Nambudiripad, K B M

    2014-01-01

    After presenting the theory in engineers' language without the unfriendly abstraction of pure mathematics, several illustrative examples are discussed in great detail to see how the various functions of the Bessel family enter into the solution of technically important problems. Axisymmetric vibrations of a circular membrane, oscillations of a uniform chain, heat transfer in circular fins, buckling of columns of varying cross-section, vibrations of a circular plate and current density in a conductor of circular cross-section are considered. The problems are formulated purely from physical considerations (using, for example, Newton's law of motion, Fourier's law of heat conduction electromagnetic field equations, etc.) Infinite series expansions, recurrence relations, manipulation of expressions involving Bessel functions, orthogonality and expansion in Fourier-Bessel series are also covered in some detail. Some important topics such as asymptotic expansions, generating function and Sturm-Lioville theory are r...

  15. Algebraic functions

    CERN Document Server

    Bliss, Gilbert Ames

    1933-01-01

    This book, immediately striking for its conciseness, is one of the most remarkable works ever produced on the subject of algebraic functions and their integrals. The distinguishing feature of the book is its third chapter, on rational functions, which gives an extremely brief and clear account of the theory of divisors.... A very readable account is given of the topology of Riemann surfaces and of the general properties of abelian integrals. Abel's theorem is presented, with some simple applications. The inversion problem is studied for the cases of genus zero and genus unity. The chapter on t

  16. Functional neurosurgery

    African Journals Online (AJOL)

    term saving of money are the reasons why developing countries should be investing in functional neurosurgery units. Surgery for medical refractory epilepsy can save large amounts of money in the long run if one considers the cost of second and thirdline antiepileptic drugs and the associated morbidity of uncontrolled ...

  17. Functional hyposplenism.

    Science.gov (United States)

    Kirkineska, L; Perifanis, V; Vasiliadis, T

    2014-01-01

    Functional hyposplenism is a condition accompanying many diseases such as sickle cell disease, celiac disease, alcoholic liver disease, hepatic cirrhosis, lymphomas and autoimmune disorders. It is characterised mostly by defective immune responses against infectious agents, especially encapsulated organisms, since the spleen is thought to play an important role in the production and maturation of B-memory lymphocytes and other substances like opsonins, both of which are considered crucial elements of the immune system for fighting infections. It is also associated with thrombocytosis, which might lead to thromboembolic events. Functional hyposplenism is diagnosed by the presence of Howell-Jolly bodies and pitted erythrocytes in the peripheral blood smear, and by nuclear imaging modalities such as spleen scintigraphy with the use of Technetium-99m and/or spleen scintigraphy with the use of heat-damaged Technetium-99m labeled erythrocytes. Severe infections accompanying functional hyposplenism can lead to the overwhelming post infection syndrome, which can often be fatal. Identifying patients with functional hyposplenism is important because simple measures such as vaccination against common infective microorganisms (e.g. Streptococcus pneumonia, Neisseria meningitides and Haemophilous influenzae) and antibiotic therapy when needed are considered beneficial in diminishing the frequency and gravity of the infections accompanying the syndrome.

  18. Functional dyspepsia

    NARCIS (Netherlands)

    Kleibeuker, JH; Thijs, JC

    2004-01-01

    Purpose of review Functional dyspepsia is a common disorder, most of the time of unknown etiology and with variable pathophysiology. Therapy has been and still is largely empirical. Data from recent studies provide new clues for targeted therapy based on knowledge of etiology and pathophysiologic

  19. Composite Structural Motifs of Binding Sites for Delineating Biological Functions of Proteins

    Science.gov (United States)

    Kinjo, Akira R.; Nakamura, Haruki

    2012-01-01

    Most biological processes are described as a series of interactions between proteins and other molecules, and interactions are in turn described in terms of atomic structures. To annotate protein functions as sets of interaction states at atomic resolution, and thereby to better understand the relation between protein interactions and biological functions, we conducted exhaustive all-against-all atomic structure comparisons of all known binding sites for ligands including small molecules, proteins and nucleic acids, and identified recurring elementary motifs. By integrating the elementary motifs associated with each subunit, we defined composite motifs that represent context-dependent combinations of elementary motifs. It is demonstrated that function similarity can be better inferred from composite motif similarity compared to the similarity of protein sequences or of individual binding sites. By integrating the composite motifs associated with each protein function, we define meta-composite motifs each of which is regarded as a time-independent diagrammatic representation of a biological process. It is shown that meta-composite motifs provide richer annotations of biological processes than sequence clusters. The present results serve as a basis for bridging atomic structures to higher-order biological phenomena by classification and integration of binding site structures. PMID:22347478

  20. Functional Credentials

    Directory of Open Access Journals (Sweden)

    Deuber Dominic

    2018-04-01

    Full Text Available A functional credential allows a user to anonymously prove possession of a set of attributes that fulfills a certain policy. The policies are arbitrary polynomially computable predicates that are evaluated over arbitrary attributes. The key feature of this primitive is the delegation of verification to third parties, called designated verifiers. The delegation protects the privacy of the policy: A designated verifier can verify that a user satisfies a certain policy without learning anything about the policy itself. We illustrate the usefulness of this property in different applications, including outsourced databases with access control. We present a new framework to construct functional credentials that does not require (non-interactive zero-knowledge proofs. This is important in settings where the statements are complex and thus the resulting zero-knowledge proofs are not efficient. Our construction is based on any predicate encryption scheme and the security relies on standard assumptions. A complexity analysis and an experimental evaluation confirm the practicality of our approach.

  1. Lung function

    International Nuclear Information System (INIS)

    Sorichter, S.

    2009-01-01

    The term lung function is often restricted to the assessment of volume time curves measured at the mouth. Spirometry includes the assessment of lung volumes which can be mobilised with the corresponding flow-volume curves. In addition, lung volumes that can not be mobilised, such as the residual volume, or only partially as FRC and TLC can be measured by body plethysmography combined with the determination of the airway resistance. Body plethysmography allows the correct positioning of forced breathing manoeuvres on the volume-axis, e.g. before and after pharmacotherapy. Adding the CO single breath transfer factor (T LCO ), which includes the measurement of the ventilated lung volume using He, enables a clear diagnosis of different obstructive, restrictive or mixed ventilatory defects with and without trapped air. Tests of reversibility and provocation, as well as the assessment of inspiratory mouth pressures (PI max , P 0.1 ) help to classify the underlying disorder and to clarify treatment strategies. For further information and to complete the diagnostic of disturbances of the ventilation, diffusion and/or perfusion (capillar-)arterial bloodgases at rest and under physical strain sometimes amended by ergospirometry are recommended. Ideally, lung function measurements are amended by radiological and nuclear medicine techniques. (orig.) [de

  2. Functional Angioplasty

    Directory of Open Access Journals (Sweden)

    Rohit Tewari

    2013-01-01

    Full Text Available Coronary angiography underestimates or overestimates lesion severity, but still remains the cornerstone in the decision making for revascularization for an overwhelming majority of interventional cardiologists. Guidelines recommend and endorse non invasive functional evaluation ought to precede revascularization. In real world practice, this is adopted in less than 50% of patients who go on to have some form of revascularization. Fractional flow reserve (FFR is the ratio of maximal blood flow in a stenotic coronary relative to maximal flow in the same vessel, were it normal. Being independent of changes in heart rate, BP or prior infarction; and take into account the contribution of collateral blood flow. It is a majorly specific index with a reasonably high sensitivity (88%, specificity (100%, positive predictive value (100%, and overall accuracy (93%. Whilst FFR provides objective determination of ischemia and helps select appropriate candidates for revascularization (for both CABG and PCI in to cath lab itself before intervention, whereas intravascular ultrasound/optical coherence tomography guidance in PCI can secure the procedure by optimizing stent expansion. Functional angioplasty simply is incorporating both intravascular ultrasound and FFR into our daily Intervention practices.

  3. Mitochondrial function and autophagy: integrating proteotoxic, redox, and metabolic stress in Parkinson's disease.

    Science.gov (United States)

    Zhang, Jianhua; Culp, Matilda Lillian; Craver, Jason G; Darley-Usmar, Victor

    2018-01-17

    Parkinson's disease (PD) is a movement disorder with widespread neurodegeneration in the brain. Significant oxidative, reductive, metabolic, and proteotoxic alterations have been observed in PD postmortem brains. The alterations of mitochondrial function resulting in decreased bioenergetic health is important and needs to be further examined to help develop biomarkers for PD severity and prognosis. It is now becoming clear that multiple hits on metabolic and signaling pathways are likely to exacerbate PD pathogenesis. Indeed, data obtained from genetic and genome association studies have implicated interactive contributions of genes controlling protein quality control and metabolism. For example, loss of key proteins that are responsible for clearance of dysfunctional mitochondria through a process called mitophagy has been found to cause PD, and a significant proportion of genes associated with PD encode proteins involved in the autophagy-lysosomal pathway. In this review, we highlight the evidence for the targeting of mitochondria by proteotoxic, redox and metabolic stress, and the role autophagic surveillance in maintenance of mitochondrial quality. Furthermore, we summarize the role of α-synuclein, leucine-rich repeat kinase 2, and tau in modulating mitochondrial function and autophagy. Among the stressors that can overwhelm the mitochondrial quality control mechanisms, we will discuss 4-hydroxynonenal and nitric oxide. The impact of autophagy is context depend and as such can have both beneficial and detrimental effects. Furthermore, we highlight the potential of targeting mitochondria and autophagic function as an integrated therapeutic strategy and the emerging contribution of the microbiome to PD susceptibility. © 2018 International Society for Neurochemistry.

  4. Proliferative reactive gliosis is compatible with glial metabolic support and neuronal function

    Directory of Open Access Journals (Sweden)

    Fero Matthew

    2011-10-01

    Full Text Available Abstract Background The response of mammalian glial cells to chronic degeneration and trauma is hypothesized to be incompatible with support of neuronal function in the central nervous system (CNS and retina. To test this hypothesis, we developed an inducible model of proliferative reactive gliosis in the absence of degenerative stimuli by genetically inactivating the cyclin-dependent kinase inhibitor p27Kip1 (p27 or Cdkn1b in the adult mouse and determined the outcome on retinal structure and function. Results p27-deficient Müller glia reentered the cell cycle, underwent aberrant migration, and enhanced their expression of intermediate filament proteins, all of which are characteristics of Müller glia in a reactive state. Surprisingly, neuroglial interactions, retinal electrophysiology, and visual acuity were normal. Conclusion The benign outcome of proliferative reactive Müller gliosis suggests that reactive glia display context-dependent, graded and dynamic phenotypes and that reactivity in itself is not necessarily detrimental to neuronal function.

  5. Functional Myelography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S. R.; Park, S. K.; Kim, J. J. [Hanyang University College of Medicine, Seoul (Korea, Republic of); Jeon, H. J.; Jeon, H. S.; Kim, D. Y. [Gang Nam Hospital, Seoul (Korea, Republic of)

    1984-09-15

    Morphologic changes of spinal canal and dural sac during spinal movement (flexion-extension) were analysed and reported with the base of cross sectional anatomy, as early as 1942. After that, this movement was emphasized and used in myelography in many countries under the name of functional myelography, for accurate diagnosis of spinal stenosis as herniated disc, but nor used commonly in Korea. Authors analysed functional myelographic findings of 78 cases, 37 of normal and 41 of surgically confirmed herniated disc, to intend to confirm the necessity of spinal movement during myelography. The results were as follows; 1. In normal group, anterior border of dural sac is stright with flexion, but indented in extension at the level of intervertebral space and this indentation is less prominent at L5-S1. 2. In normal group with extension, posterior indentation of dural sac is more prominent at the level of intervertebral space than body, A-P diameter of dural sac is narrowed all the level of intervertebral space except L5-S1,and dural sac moved anteriorly (near to the posterior portion of spinal body or intervertebral space) at the level L5-S1 and all spinal body. 3. In disc patient, anterior indentation of dural sac is persist in both views (flexion and extension) and much more exaggerated with extension, but less prominent at L5-S1. 4. In herniated disc patient with extension, anterior movement of anterior dural border at the level of L5-S1 is much decreased than normal.

  6. Functional Myelography

    International Nuclear Information System (INIS)

    Lee, S. R.; Park, S. K.; Kim, J. J.; Jeon, H. J.; Jeon, H. S.; Kim, D. Y.

    1984-01-01

    Morphologic changes of spinal canal and dural sac during spinal movement (flexion-extension) were analysed and reported with the base of cross sectional anatomy, as early as 1942. After that, this movement was emphasized and used in myelography in many countries under the name of functional myelography, for accurate diagnosis of spinal stenosis as herniated disc, but nor used commonly in Korea. Authors analysed functional myelographic findings of 78 cases, 37 of normal and 41 of surgically confirmed herniated disc, to intend to confirm the necessity of spinal movement during myelography. The results were as follows; 1. In normal group, anterior border of dural sac is stright with flexion, but indented in extension at the level of intervertebral space and this indentation is less prominent at L5-S1. 2. In normal group with extension, posterior indentation of dural sac is more prominent at the level of intervertebral space than body, A-P diameter of dural sac is narrowed all the level of intervertebral space except L5-S1,and dural sac moved anteriorly (near to the posterior portion of spinal body or intervertebral space) at the level L5-S1 and all spinal body. 3. In disc patient, anterior indentation of dural sac is persist in both views (flexion and extension) and much more exaggerated with extension, but less prominent at L5-S1. 4. In herniated disc patient with extension, anterior movement of anterior dural border at the level of L5-S1 is much decreased than normal.

  7. Functional analysis

    CERN Document Server

    Kesavan, S

    2009-01-01

    The material presented in this book is suited for a first course in Functional Analysis which can be followed by Masters students. While covering all the standard material expected of such a course, efforts have been made to illustrate the use of various theorems via examples taken from differential equations and the calculus of variations, either through brief sections or through exercises. In fact, this book will be particularly useful for students who would like to pursue a research career in the applications of mathematics. The book includes a chapter on weak and weak topologies and their applications to the notions of reflexivity, separability and uniform convexity. The chapter on the Lebesgue spaces also presents the theory of one of the simplest classes of Sobolev spaces. The book includes a chapter on compact operators and the spectral theory for compact self-adjoint operators on a Hilbert space. Each chapter has large collection of exercises at the end. These illustrate the results of the text, show ...

  8. Functional Kaolinite.

    Science.gov (United States)

    Detellier, Christian

    2018-01-04

    The world resources of all clays are extremely large. Among the various types of clays, the world mine production of kaolin in 2016 was 37.0 Mt, the largest mined clay. Kaolin is traditionally used in ceramics, refractories and as paper coating and filling. But kaolin, as it is demonstrated in this paper, has a bright potential for use in non-traditional, high value-added, applications. This is particularly true for its principal component: the mineral species kaolinite which has a chemical structure allowing its functionalization, leading to a variety of potential applications. Kaolinite is a layered 1 : 1 clay mineral, the layer being made of two different sheets, a tetrahedral silica sheet and an octahedral alumina sheet. Large dipole-dipole interactions, in addition to a network of H-bonds, link the siloxane surface of a layer to the aluminol surface of another layer, making intercalation of guest species in kaolinite challenging. There is however a limited number of molecular units (molecules or salts) that can directly intercalate in kaolinite to form "pre-intercalates". Once intercalated these molecular units can be exchanged by a large number and variety of guests, providing access to the interlayer space of kaolinite, and to its reactive aluminol internal surfaces. The intercalation of molecules of pharmacological interest showed the potential of kaolinite to act as a slow-releasing agent for drugs, and the intercalation of polymers resulted in the creation of intercalated nanocomposites. The intercalation of ionic liquids gave materials with ionic conductivity properties in the solid-state. Intercalates are however unstable in water. One needed to make these organo-inorgano nanohybrid materials resistant to hydrolysis and more thermally stable. The network of aluminol groups on the internal surfaces of kaolinite offers the opportunity to design and create controlled organo-inorgano nanohybrid materials, taking advantage of their reactivity, in

  9. Plant functional traits of dominant native and invasive species in mediterranean-climate ecosystems.

    Science.gov (United States)

    Funk, Jennifer L; Standish, Rachel J; Stock, William D; Valladares, Fernando

    2016-01-01

    The idea that dominant invasive plant species outperform neighboring native species through higher rates of carbon assimilation and growth is supported by several analyses of global data sets. However, theory suggests that native and invasive species occurring in low-resource environments will be functionally similar, as environmental factors restrict the range of observed physiological and morphological trait values. We measured resource-use traits in native and invasive plant species across eight diverse vegetation communities distributed throughout the five mediterranean-climate regions, which are drought prone and increasingly threatened by human activities, including the introduction of exotic species. Traits differed strongly across the five regions. In regions with functional differences between native and invasive species groups, invasive species displayed traits consistent with high resource acquisition; however, these patterns were largely attributable to differences in life form. We found that species invading mediterranean-climate regions were more likely to be annual than perennial: three of the five regions were dominated by native woody species and invasive annuals. These results suggest that trait differences between native and invasive species are context dependent and will vary across vegetation communities. Native and invasive species within annual and perennial groups had similar patterns of carbon assimilation and resource use, which contradicts the widespread idea that invasive species optimize resource acquisition rather than resource conservation. .

  10. Transgenic mouse models in the study of reproduction: insights into GATA protein function.

    Science.gov (United States)

    Tevosian, Sergei G

    2014-07-01

    For the past 2 decades, transgenic technology in mice has allowed for an unprecedented insight into the transcriptional control of reproductive development and function. The key factor among the mouse genetic tools that made this rapid advance possible is a conditional transgenic approach, a particularly versatile method of creating gene deletions and substitutions in the mouse genome. A centerpiece of this strategy is an enzyme, Cre recombinase, which is expressed from defined DNA regulatory elements that are active in the tissue of choice. The regulatory DNA element (either genetically engineered or natural) assures Cre expression only in predetermined cell types, leading to the guided deletion of genetically modified (flanked by loxP or 'floxed' by loxP) gene loci. This review summarizes and compares the studies in which genes encoding GATA family transcription factors were targeted either globally or by Cre recombinases active in the somatic cells of ovaries and testes. The conditional gene loss experiments require detailed knowledge of the spatial and temporal expression of Cre activity, and the challenges in interpreting the outcomes are highlighted. These studies also expose the complexity of GATA-dependent regulation of gonadal gene expression and suggest that gene function is highly context dependent. © 2014 Society for Reproduction and Fertility.

  11. Special functions & their applications

    CERN Document Server

    Lebedev, N N

    1972-01-01

    Famous Russian work discusses the application of cylinder functions and spherical harmonics; gamma function; probability integral and related functions; Airy functions; hyper-geometric functions; more. Translated by Richard Silverman.

  12. On the directive function of episodic memories in people's lives: a look at romantic relationships.

    Science.gov (United States)

    Philippe, Frederick L; Koestner, Richard; Lekes, Natasha

    2013-01-01

    We argue that episodic memories have an active and directive function with respect to a number of relational outcomes. In line with self-determination theory, it is expected that the satisfaction of 3 needs (autonomy, competence, relatedness) in couple-related memories facilitates the quality of romantic relationships and their development. Results of 4 studies support this contention. Study 1 showed that need satisfaction in couple-related memories was associated with relationship quality, even after controlling for other important relational constructs. Study 2 underscored the context-dependent aspect of the directive function of episodic memories. Need satisfaction in couple-related memories was found to be associated with partner relationship quality but not with friendship quality, whereas need satisfaction in friend-related memories was associated with friendship quality but not with partner relationship quality. Study 3 showed that couple-related memories contributed independently to each partner's perceptions of relationship quality, that is, both the rememberer and the partner. Study 4 showed the long-term directive function of episodic memories. Need satisfaction in couple-related memories positively and negatively predicted increases in relationship quality and the likelihood of a breakup over a 1-year period, respectively. This directive function of memories was examined along with the self function of memories (self-enhancement, self-protection) and shown to be complementary. We also examined the stability of need satisfaction in couple-related memories over time and investigated this stability as a function of whether the partners had broken up or not over the year. Overall, the findings suggest that episodic memories play an important role in romantic relationships.

  13. Functional Programming in R

    DEFF Research Database (Denmark)

    Mailund, Thomas

    Master functions and discover how to write functional programs in R. In this book, you'll make your functions pure by avoiding side-effects; you’ll write functions that manipulate other functions, and you’ll construct complex functions using simpler functions as building blocks. In Functional...... Programming in R, you’ll see how we can replace loops, which can have side-effects, with recursive functions that can more easily avoid them. In addition, the book covers why you shouldn't use recursion when loops are more efficient and how you can get the best of both worlds. Functional programming...... functions by combining simpler functions. You will: Write functions in R including infix operators and replacement functions Create higher order functions Pass functions to other functions and start using functions as data you can manipulate Use Filer, Map and Reduce functions to express the intent behind...

  14. Sharpening the edges of understanding the structure/function of the LPA1 receptor

    Science.gov (United States)

    Murph, Mandi; Nguyen, Giang; Radhakrishna, Harish; Mills, Gordon B.

    2008-01-01

    Since the molecular cloning of the vzg-1/Edg-2/LPA1 gene, studies have attempted to characterize LPA1 receptor functionality into a single categorical role, different from the other Edg-family LPA receptors. The desire to categorize LPA1 function has highlighted its complexity and demonstrated that the LPA1 receptor does not have one absolute function throughout every system. The central nervous system is highly enriched in the LPA1 receptor, suggesting an integral role in neuronal processes. Metastatic and invasive breast cancer also appears to have LPA-mediated LPA1 receptor functions that enhance phenotypes associated with tumorigenesis. LPA1 possesses a number of motifs conserved among G protein-coupled receptors (GPCRs): a DRY-like motif, a PDZ domain, Ser/Thr predicted sites of phosphorylation, a dileucine motif, double cysteines in the tail and conserved residues that stabilize structure and determine ligand binding. The third intracellular loop of the LPA1 receptor may be the crux of receptor signaling and attenuation with phosphorylation of Thr-236 potentially a key determinant of basal LPA1 signaling. Mutagenesis data supports the notion that Thr-236 regulates this process since mutating Thr-236 to Ala-236 increased basal and LPA-mediated serum response factor (SRF) signaling activity and Lys-236 further increased this basal signaling. Here we describe progress on defining the major functions of the LPA1 receptor, discuss a context dependent dualistic role as both a negative regulator in cancer and a proto-oncogene, outline its structural components at the molecular amino-acid level and present mutagenesis data on the third intracellular loop of the receptor. PMID:18501205

  15. Functional Training Revisited.

    Science.gov (United States)

    Siff, Mel C.

    2002-01-01

    Asserts that though functional training is vital in all sporting preparation, it is only one aspect of the overall process. The paper defines functional training; discusses facets of functionality, functionality and balancing drills, and functional training and periodization; and concludes that functionality is best defined in terms of the outcome…

  16. Signaling context modulates social function of silent bared-teeth displays in rhesus macaques (Macaca mulatta).

    Science.gov (United States)

    Beisner, Brianne A; McCowan, Brenda

    2014-02-01

    The signaling context has been found to change the meaning of the silent bared-teeth display (SBT) in pigtail macaques (Macaca nemestrina) such that the SBT in apparently peaceful contexts communicates subordination, a long-term pattern of behavior, whereas in conflict contexts it communicates immediate submission (PNAS, 104: 1581-1586). However, the context dependent nature of the SBT has not yet been explored in other species. We investigated SBT usage with respect to grooming, severe aggression, and signaler-receiver sex, rank difference, and body size in seven captive groups of rhesus macaques. Peaceful SBTs were given most often to male receivers by male and female signalers whereas conflict SBTs were given to both male and female receivers primarily by female signalers. Male signalers rarely gave SBTs (peaceful or conflict) to female receivers. Unlike pigtail macaques, peaceful SBTs in rhesus were often accompanied by withdrawal behavior (referred to as peaceful SBT-leave), which influenced grooming, but not aggression, at the dyadic level. Severe aggression was less frequent among dyads using peaceful SBTs (regardless of withdrawal behavior) than those using conflict SBTs. In contrast, grooming was more frequent among dyads using peaceful SBT-stay signals than those using peaceful SBT-leave signals or conflict SBTs. In total, our results indicate that peaceful SBTs are a functionally different signal from conflict SBTs in rhesus macaques. © 2013 Wiley Periodicals, Inc.

  17. Prey diversity effects on ecosystem functioning depend on consumer identity and prey composition.

    Science.gov (United States)

    Wohlgemuth, Daniel; Filip, Joanna; Hillebrand, Helmut; Moorthi, Stefanie D

    2017-07-01

    Consumer diversity effects on ecosystem functioning are highly context dependent and are determined by consumer specialization and other consumer and prey specific traits such as growth and grazing rates. Despite complex reciprocal interactions between consumers and their prey, few experimental studies have focused on prey diversity effects on consumer dynamics and trophic transfer. In microbial microcosms, we investigated effects of algal prey diversity (one, two and four species) on the production, evenness and grazing rates of 4 ciliate consumers, differing in grazing preferences and rates. Prey diversity increased prey biovolume in the absence of consumers and had opposing effects on different consumers, depending on their specialization and their preferred prey. Consumers profited from prey mixtures compared to monocultures of non-preferred prey, but responded negatively if preferred prey species were offered together with other species. Prey diversity increased consumer evenness by preventing dominance of specific consumers, demonstrating that the loss of prey species may have cascading effects resulting in reduced consumer diversity. Our study emphasizes that not only the degree of specialization but also the selectivity for certain prey species within the dietary niche may alter the consequences of changing prey diversity in a food web context.

  18. Functional networks involved in spatial learning strategies in middle-aged rats.

    Science.gov (United States)

    Begega, A; Cuesta, M; Rubio, S; Méndez, M; Santín, L J; Arias, J L

    2012-03-01

    Our aim was to assess the way that middle-aged rats solve spatial learning tasks that can be performed using different strategies. We assessed the brain networks involved in these spatial learning processes using Principal Component Analysis. Two tasks were performed in a complex context, a four-arm radial maze, in which each group must use either an allocentric or an egocentric strategy. Another task was performed in a simple T-maze in which rats must use an egocentric strategy. Brain metabolic activity was quantified to evaluate neural changes related to spatial learning in the described tasks. Our findings revealed that two functional networks are involved in spatial learning in aged rats. One of the networks, spatial processing, is composed of brain regions involved in the integration of sensory and motivational information. The other network, context-dependent processing, mainly involves the dorsal hippocampus and is related to the processing of contextual information from the environment. Both networks work together to solve spatial tasks in a complex spatial environment. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Functional Programming in R

    DEFF Research Database (Denmark)

    Mailund, Thomas

    2017-01-01

    Master functions and discover how to write functional programs in R. In this book, you'll make your functions pure by avoiding side-effects; you’ll write functions that manipulate other functions, and you’ll construct complex functions using simpler functions as building blocks. In Functional...... Programming in R, you’ll see how we can replace loops, which can have side-effects, with recursive functions that can more easily avoid them. In addition, the book covers why you shouldn't use recursion when loops are more efficient and how you can get the best of both worlds. Functional programming...

  20. [Psychological function in aging].

    Science.gov (United States)

    Wada, Kenji; Yamamoto, Mikie; Nakashima, Kenji

    2013-10-01

    Physical function was declined in aging as well as sensory function in human. Motor slowness and unbalance gait occur as well as decline of ability visual acuity and hearing let elderly people live in limited daily activity. Psychological functions are also thought to be decline in aging. In International Classification of Functioning, Disability and Health(ICF), psychological functions are classified into attention, memory, psychomotor, emotion, perception, thought, higher-level cognitive functions, language, calculation, sequencing complex movements, experience of self and time functions and unspecified functions. It is difficult to assess an individual psychological function itself, because some functions may affect each other and results of evaluations of a psychological function may not represent the meaning of the function. There were numerous reports on physical function in aging in a cross sectional or a longitudinal study design. In this article, we review changes of psychological function in aging.

  1. Generalized Probability Functions

    Directory of Open Access Journals (Sweden)

    Alexandre Souto Martinez

    2009-01-01

    Full Text Available From the integration of nonsymmetrical hyperboles, a one-parameter generalization of the logarithmic function is obtained. Inverting this function, one obtains the generalized exponential function. Motivated by the mathematical curiosity, we show that these generalized functions are suitable to generalize some probability density functions (pdfs. A very reliable rank distribution can be conveniently described by the generalized exponential function. Finally, we turn the attention to the generalization of one- and two-tail stretched exponential functions. We obtain, as particular cases, the generalized error function, the Zipf-Mandelbrot pdf, the generalized Gaussian and Laplace pdf. Their cumulative functions and moments were also obtained analytically.

  2. Functionality and homogeneity.

    NARCIS (Netherlands)

    2011-01-01

    Functionality and homogeneity are two of the five Sustainable Safety principles. The functionality principle aims for roads to have but one exclusive function and distinguishes between traffic function (flow) and access function (residence). The homogeneity principle aims at differences in mass,

  3. Investigating body function

    International Nuclear Information System (INIS)

    Monks, R.; Riley, A.L.M.

    1981-01-01

    This invention relates to the investigation of body function, especially small bowel function but also liver function, using bile acids and bile salts or their metabolic precursors labelled with radio isotopes and selenium or tellurium. (author)

  4. Random functions and turbulence

    CERN Document Server

    Panchev, S

    1971-01-01

    International Series of Monographs in Natural Philosophy, Volume 32: Random Functions and Turbulence focuses on the use of random functions as mathematical methods. The manuscript first offers information on the elements of the theory of random functions. Topics include determination of statistical moments by characteristic functions; functional transformations of random variables; multidimensional random variables with spherical symmetry; and random variables and distribution functions. The book then discusses random processes and random fields, including stationarity and ergodicity of random

  5. Every storage function is a state function

    NARCIS (Netherlands)

    Trentelman, H.L.; Willems, J.C.

    1997-01-01

    It is shown that for linear dynamical systems with quadratic supply rates, a storage function can always be written as a quadratic function of the state of an associated linear dynamical system. This dynamical system is obtained by combining the dynamics of the original system with the dynamics of

  6. The Interpretive Function

    DEFF Research Database (Denmark)

    Agerbo, Heidi

    2017-01-01

    Approximately a decade ago, it was suggested that a new function should be added to the lexicographical function theory: the interpretive function(1). However, hardly any research has been conducted into this function, and though it was only suggested that this new function was relevant to incorp......Approximately a decade ago, it was suggested that a new function should be added to the lexicographical function theory: the interpretive function(1). However, hardly any research has been conducted into this function, and though it was only suggested that this new function was relevant...... to incorporate into lexicographical theory, some scholars have since then assumed that this function exists(2), including the author of this contribution. In Agerbo (2016), I present arguments supporting the incorporation of the interpretive function into the function theory and suggest how non-linguistic signs...... can be treated in specific dictionary articles. However, in the current article, due to the results of recent research, I argue that the interpretive function should not be considered an individual main function. The interpretive function, contrary to some of its definitions, is not connected...

  7. Functional Object Analysis

    DEFF Research Database (Denmark)

    Raket, Lars Lau

    -effect formulations, where the observed functional signal is assumed to consist of both fixed and random functional effects. This thesis takes the initial steps toward the development of likelihood-based methodology for functional objects. We first consider analysis of functional data defined on high...

  8. Cryptographic Hash Functions

    DEFF Research Database (Denmark)

    Thomsen, Søren Steffen

    2009-01-01

    functions have received a huge amount of attention due to new attacks on widely used hash functions. This PhD thesis, having the title "Cryptographic Hash Functions", contains both a general description of cryptographic hash functions, including their applications and expected properties as well as some...

  9. Functional Programming in R

    DEFF Research Database (Denmark)

    Mailund, Thomas

    Master functions and discover how to write functional programs in R. In this book, you'll make your functions pure by avoiding side-effects; you’ll write functions that manipulate other functions, and you’ll construct complex functions using simpler functions as building blocks. In Functional...... Programming in R, you’ll see how we can replace loops, which can have side-effects, with recursive functions that can more easily avoid them. In addition, the book covers why you shouldn't use recursion when loops are more efficient and how you can get the best of both worlds. Functional programming...... is a style of programming, like object-oriented programming, but one that focuses on data transformations and calculations rather than objects and state. Where in object-oriented programming you model your programs by describing which states an object can be in and how methods will reveal or modify...

  10. The Interpretive Function

    DEFF Research Database (Denmark)

    Agerbo, Heidi

    2017-01-01

    to acting and therefore the only difference between reception and interpretation is that they work with different types of sign. However, the type of sign is not relevant for a function, or rather, it should not be a criterion for distinguishing between functions. The lemma selection for the communicative......Approximately a decade ago, it was suggested that a new function should be added to the lexicographical function theory: the interpretive function(1). However, hardly any research has been conducted into this function, and though it was only suggested that this new function was relevant...... to incorporate into lexicographical theory, some scholars have since then assumed that this function exists(2), including the author of this contribution. In Agerbo (2016), I present arguments supporting the incorporation of the interpretive function into the function theory and suggest how non-linguistic signs...

  11. TRAF6 regulates satellite stem cell self-renewal and function during regenerative myogenesis

    Science.gov (United States)

    Hindi, Sajedah M.; Kumar, Ashok

    2015-01-01

    Satellite cells are a stem cell population within adult muscle and are responsible for myofiber regeneration upon injury. Satellite cell dysfunction has been shown to underlie the loss of skeletal muscle mass in many acquired and genetic muscle disorders. The transcription factor paired box-protein-7 (PAX7) is indispensable for supplementing the reservoir of satellite cells and driving regeneration in normal and diseased muscle. TNF receptor–associated factor 6 (TRAF6) is an adaptor protein and an E3 ubiquitin ligase that mediates the activation of multiple cell signaling pathways in a context-dependent manner. Here, we demonstrated that TRAF6-mediated signaling is critical for homeostasis of satellite cells and their function during regenerative myogenesis. Selective deletion of Traf6 in satellite cells of adult mice led to profound muscle regeneration defects and dramatically reduced levels of PAX7 and late myogenesis markers. TRAF6 was required for the activation of MAPKs ERK1/2 and JNK1/2, which in turn activated the transcription factor c-JUN, which binds the Pax7 promoter and augments Pax7 expression. Moreover, TRAF6/c-JUN signaling repressed the levels of the microRNAs miR-1 and miR-206, which promote differentiation, to maintain PAX7 levels in satellite cells. We also determined that satellite cell–specific deletion of Traf6 exaggerates the dystrophic phenotype in the mdx (a mouse model of Duchenne muscular dystrophy) mouse by blunting the regeneration of injured myofibers. Collectively, our study reveals an essential role for TRAF6 in satellite stem cell function. PMID:26619121

  12. Sampling functions for geophysics

    Science.gov (United States)

    Giacaglia, G. E. O.; Lunquist, C. A.

    1972-01-01

    A set of spherical sampling functions is defined such that they are related to spherical-harmonic functions in the same way that the sampling functions of information theory are related to sine and cosine functions. An orderly distribution of (N + 1) squared sampling points on a sphere is given, for which the (N + 1) squared spherical sampling functions span the same linear manifold as do the spherical-harmonic functions through degree N. The transformations between the spherical sampling functions and the spherical-harmonic functions are given by recurrence relations. The spherical sampling functions of two arguments are extended to three arguments and to nonspherical reference surfaces. Typical applications of this formalism to geophysical topics are sketched.

  13. Functionalized boron nitride nanotubes

    Science.gov (United States)

    Sainsbury, Toby; Ikuno, Takashi; Zettl, Alexander K

    2014-04-22

    A plasma treatment has been used to modify the surface of BNNTs. In one example, the surface of the BNNT has been modified using ammonia plasma to include amine functional groups. Amine functionalization allows BNNTs to be soluble in chloroform, which had not been possible previously. Further functionalization of amine-functionalized BNNTs with thiol-terminated organic molecules has also been demonstrated. Gold nanoparticles have been self-assembled at the surface of both amine- and thiol-functionalized boron nitride Nanotubes (BNNTs) in solution. This approach constitutes a basis for the preparation of highly functionalized BNNTs and for their utilization as nanoscale templates for assembly and integration with other nanoscale materials.

  14. A Blue Lagoon Function

    DEFF Research Database (Denmark)

    Markvorsen, Steen

    2007-01-01

    We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$.......We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$....

  15. Scattering function S (Q, w), correlation functions

    International Nuclear Information System (INIS)

    Binder, K.

    1978-01-01

    The following subjects are dealt with in this paper: 1) Two-Particle problem in quantum mechanics and inelastic scattering 2) The doubly differential cross section for many-particle systems 3) The van Hove transformation and the scattering funktion S (Q, w) 4) Relation between scattering functions and correlation functions 5) Examples: ideal gas, liquids 6) Differential cross section, sum rules, convolution approximation. (orig.) [de

  16. A ‘Judicious’ Use of L1 in TL Classroom: Socio-political, Psychological and Functional Dimensions

    Directory of Open Access Journals (Sweden)

    Muhammad Afzal Awan

    2015-10-01

    Full Text Available In the present study, the authors deliberate that there are no separate boxes in human brain to restrict two different languages to interact with each other. The practice on ground is strongly in favour of allowing L1 to support target language (TL. The paper contests the status quo of maximal input hypothesis and documents enough research in the field of human psychology, code-switching, bilingualism and Socio-Cultural Theory (SCT. The Canadian French Immersion Programme has also been referred to, in the article. The real life teaching and learning experiences have been shared and are connected to the latest theory and research, and it is concluded that this issue has serious socio-political and academic dimensions. The study postulates that the extent of L1 to be used is highly context-dependent.  A ‘judicious’ use of L1 should, however, be practiced in target language (TL class without malign. Keywords: Judicious use, L1, code-switching, socio-political, psychological, functional dimensions

  17. Functional Median Polish

    KAUST Repository

    Sun, Ying

    2012-08-03

    This article proposes functional median polish, an extension of univariate median polish, for one-way and two-way functional analysis of variance (ANOVA). The functional median polish estimates the functional grand effect and functional main factor effects based on functional medians in an additive functional ANOVA model assuming no interaction among factors. A functional rank test is used to assess whether the functional main factor effects are significant. The robustness of the functional median polish is demonstrated by comparing its performance with the traditional functional ANOVA fitted by means under different outlier models in simulation studies. The functional median polish is illustrated on various applications in climate science, including one-way and two-way ANOVA when functional data are either curves or images. Specifically, Canadian temperature data, U. S. precipitation observations and outputs of global and regional climate models are considered, which can facilitate the research on the close link between local climate and the occurrence or severity of some diseases and other threats to human health. © 2012 International Biometric Society.

  18. To boldly gulp: standard metabolic rate and boldness have context-dependent influences on risk-taking to breathe air in a catfish.

    Science.gov (United States)

    McKenzie, David J; Belão, Thiago C; Killen, Shaun S; Rantin, F Tadeu

    2015-12-01

    The African sharptooth catfish Clarias gariepinus has bimodal respiration, it has a suprabranchial air-breathing organ alongside substantial gills. We used automated bimodal respirometry to reveal that undisturbed juvenile catfish (N=29) breathed air continuously in normoxia, with a marked diurnal cycle. Air breathing and routine metabolic rate (RMR) increased in darkness when, in the wild, this nocturnal predator forages. Aquatic hypoxia (20% air saturation) greatly increased overall reliance on air breathing. We investigated whether two measures of risk taking to breathe air, namely absolute rates of aerial O2 uptake (ṀO2,air) and the percentage of RMR obtained from air (%ṀO2,air), were influenced by individual standard metabolic rate (SMR) and boldness. In particular, whether any influence varied with resource availability (normoxia versus hypoxia) or relative fear of predation (day versus night). Individual SMR, derived from respirometry, had an overall positive influence on ṀO2,air across all contexts but a positive influence on %ṀO2,air only in hypoxia. Thus, a pervasive effect of SMR on air breathing became most acute in hypoxia, when individuals with higher O2 demand took proportionally more risks. Boldness was estimated as time required to resume air breathing after a fearful stimulus in daylight normoxia (Tres). Although Tres had no overall influence on ṀO2,air or %ṀO2,air, there was a negative relationship between Tres and %ṀO2,air in daylight, in normoxia and hypoxia. There were two Tres response groups, 'bold' phenotypes with Tres below 75 min (N=13) which, in daylight, breathed proportionally more air than 'shy' phenotypes with Tres above 115 min (N=16). Therefore, individual boldness influenced air breathing when fear of predation was high. Thus, individual energy demand and personality did not have parallel influences on the emergent tendency to take risks to obtain a resource; their influences varied in strength with context. © 2015. Published by The Company of Biologists Ltd.

  19. Genetic selection for context-dependent stochastic phenotypes: Sp1 and TATA mutations increase phenotypic noise in HIV-1 gene expression.

    Directory of Open Access Journals (Sweden)

    Kathryn Miller-Jensen

    Full Text Available The sequence of a promoter within a genome does not uniquely determine gene expression levels and their variability; rather, promoter sequence can additionally interact with its location in the genome, or genomic context, to shape eukaryotic gene expression. Retroviruses, such as human immunodeficiency virus-1 (HIV, integrate their genomes into those of their host and thereby provide a biomedically-relevant model system to quantitatively explore the relationship between promoter sequence, genomic context, and noise-driven variability on viral gene expression. Using an in vitro model of the HIV Tat-mediated positive-feedback loop, we previously demonstrated that fluctuations in viral Tat-transactivating protein levels generate integration-site-dependent, stochastically-driven phenotypes, in which infected cells randomly 'switch' between high and low expressing states in a manner that may be related to viral latency. Here we extended this model and designed a forward genetic screen to systematically identify genetic elements in the HIV LTR promoter that modulate the fraction of genomic integrations that specify 'Switching' phenotypes. Our screen identified mutations in core promoter regions, including Sp1 and TATA transcription factor binding sites, which increased the Switching fraction several fold. By integrating single-cell experiments with computational modeling, we further investigated the mechanism of Switching-fraction enhancement for a selected Sp1 mutation. Our experimental observations demonstrated that the Sp1 mutation both impaired Tat-transactivated expression and also altered basal expression in the absence of Tat. Computational analysis demonstrated that the observed change in basal expression could contribute significantly to the observed increase in viral integrations that specify a Switching phenotype, provided that the selected mutation affected Tat-mediated noise amplification differentially across genomic contexts. Our study thus demonstrates a methodology to identify and characterize promoter elements that affect the distribution of stochastic phenotypes over genomic contexts, and advances our understanding of how promoter mutations may control the frequency of latent HIV infection.

  20. Examining the Effect of External Factors and Context-Dependent Beliefs of Teachers in the Use of ICT in Teaching: Using an Elaborated Theory of Planned Behavior

    Science.gov (United States)

    Salleh, Sallimah; Laxman, Kumar

    2015-01-01

    Research into teachers' attitudes, beliefs, competence, and inhibitions in relation to their use of technology may provide answers to a series of questions from administrators that relate to teachers' classroom implementation of Information and Communication Technology. The theory of planned behavior is a useful model for providing a framework for…

  1. Chimpanzees' Context-Dependent Tool Use Provides Evidence for Separable Representations of Hand and Tool Even during Active Use within Peripersonal Space

    Science.gov (United States)

    Povinelli, Daniel J.; Reaux, James E.; Frey, Scott H.

    2010-01-01

    Considerable attention has been devoted to behaviors in which tools are used to perform actions in extrapersonal space by extending the reach. Evidence suggests that these behaviors result in an expansion of the body schema and peripersonal space. However, humans often use tools to perform tasks within peripersonal space that cannot be…

  2. The ecological role of type three secretion systems in the interaction of bacteria with fungi in soil and related habitats is diverse and context-dependent

    NARCIS (Netherlands)

    Nazir, Rashid; Mazurier, Sylvie; Yang, Pu; Lemanceau, Philippe; van Elsas, Jan Dirk

    2017-01-01

    Bacteria and fungi constitute important organisms in many ecosystems, in particular terrestrial ones. Both organismal groups contribute significantly to biogeochemical cycling processes. Ecological theory postulates that bacteria capable of receiving benefits from host fungi are likely to evolve

  3. The Ecological Role of Type Three Secretion Systems in the Interaction of Bacteria with Fungi in Soil and Related Habitats Is Diverse and Context-Dependent

    Science.gov (United States)

    Nazir, Rashid; Mazurier, Sylvie; Yang, Pu; Lemanceau, Philippe; van Elsas, Jan Dirk

    2017-01-01

    Bacteria and fungi constitute important organisms in many ecosystems, in particular terrestrial ones. Both organismal groups contribute significantly to biogeochemical cycling processes. Ecological theory postulates that bacteria capable of receiving benefits from host fungi are likely to evolve efficient association strategies. The purpose of this review is to examine the mechanisms that underpin the bacterial interactions with fungi in soil and other systems, with special focus on the type III secretion system (T3SS). Starting with a brief description of the versatility of the T3SS as an interaction system with diverse eukaryotic hosts, we subsequently examine the recent advances made in our understanding of its contribution to interactions with soil fungi. The analysis used data sets ranging from circumstantial evidence to gene-knockout-based experimental data. The initial finding that the abundance of T3SSs in microbiomes is often enhanced in fungal-affected habitats like the mycosphere and the mycorrhizosphere is now substantiated with in-depth knowledge of the specific systems involved. Different fungal–interactive bacteria, in positive or negative associations with partner fungi, harbor and express T3SSs, with different ecological outcomes. In some particular cases, bacterial T3SSs have been shown to modulate the physiology of its fungal partner, affecting its ecological characteristics and consequently shaping its own habitat. Overall, the analyses of the collective data set revealed that diverse T3SSs have assumed diverse roles in the interactions of bacteria with host fungi, as driven by ecological and evolutionary niche requirements. PMID:28197129

  4. Context-dependent associations between variation in risk of ischemic heart disease and variation in the 5' promoter region of the apolipoprotein E gene in Danish women

    DEFF Research Database (Denmark)

    Stengård, Jari H; Dyson, Greg; Frikke-Schmidt, Ruth

    2010-01-01

    : In a sample of 3686 female and 2772 male participants of the Copenhagen City Heart Study who were free of IHD events, 576 individuals (257 women, 7.0% and 319 men, 11.5%) were diagnosed as having developed IHD in 6.5 years of follow-up. Using a stepwise Patient Rule-Induction Method modeling strategy...

  5. Now you see it, now you don’t: The context dependent nature of category-effects in visual object recognition

    DEFF Research Database (Denmark)

    Gerlach, Christian; Toft, Kristian Olesen

    2011-01-01

    In two experiments, we test predictions regarding processing advantages/disadvantages for natural objects and artefacts in visual object recognition. Varying three important parameters*degree of perceptual differentiation, stimulus format, and stimulus exposure duration*we show how different...

  6. A live-cell, high-content imaging survey of 206 endogenous factors across five stress conditions reveals context-dependent survival effects in mouse primary beta cells.

    Science.gov (United States)

    Yang, Yu Hsuan Carol; Wills, Quin F; Johnson, James D

    2015-06-01

    Beta cell death is a hallmark of diabetes. It is not known whether specific cellular stresses associated with type 1 or type 2 diabetes require specific factors to protect pancreatic beta cells. No systematic comparison of endogenous soluble factors in the context of multiple pro-apoptotic conditions has been published. Primary mouse islet cells were cultured in conditions mimicking five type 1 or type 2 diabetes-related stresses: basal 5 mmol/l glucose, cytokine cocktail (25 ng/ml TNF-α, 10 ng/ml IL-1β, 10 ng/ml IFN-γ), 1 μmol/l thapsigargin, 1.5 mmol/l palmitate and 20 mmol/l glucose (all in the absence of serum). We surveyed the effects of a library of 206 endogenous factors (selected based on islet expression of their receptors) on islet cell survival through multi-parameter, live-cell imaging. Our survey pointed to survival factors exhibiting generalised protective effects across conditions meant to model different types of diabetes and stages of the diseases. For example, our survey and follow-up experiments suggested that OLFM1 is a novel protective factor for mouse and human beta cells across multiple conditions. Most strikingly, we also found specific protective survival factors for each model stress condition. For example, semaphorin4A (SEMA4A) was toxic to islet cells in the serum-free baseline and serum-free 20 mmol/l glucose conditions, but protective in the context of lipotoxicity. Rank product testing supported the consistency of our observations. Collectively, our survey reveals previously unidentified islet cell survival factors and suggest their potential utility in individualised medicine.

  7. Characterisation of the Context-Dependence of the Gene Concept in Research Articles: Possible Consequences for Teaching Concepts with Multiple Meanings

    Science.gov (United States)

    Flodin, Veronica S.

    2017-01-01

    The purpose of this study is to interpret and qualitatively characterise the content in some research articles and evaluate cases of possible difference in meanings of the gene concept used. Using a reformulation of Hirst's criteria of forms of knowledge, articles from five different sub-disciplines in biology (transmission genetic, molecular…

  8. HIV-1 envelope glycoprotein resistance to monoclonal antibody 2G12 is subject-specific and context-dependent in macaques and humans

    NARCIS (Netherlands)

    Malherbe, Delphine C.; Sanders, Rogier W.; van Gils, Marit J.; Park, Byung; Gomes, Michelle M.; Schuitemaker, Hanneke; Barnett, Susan; Haigwood, Nancy L.

    2013-01-01

    HIV-1 Envelope (Env) protein is the sole target of neutralizing antibodies (NAbs) that arise during infection to neutralize autologous variants. Under this immune pressure, HIV escape variants are continuously selected and over the course of infection Env becomes more neutralization resistant. Many

  9. Physiology of the fuel ethanol strain Saccharomyces cerevisiae PE-2 at low pH indicates a context-dependent performance relevant for industrial applications.

    Science.gov (United States)

    Della-Bianca, Bianca E; de Hulster, Erik; Pronk, Jack T; van Maris, Antonius J A; Gombert, Andreas K

    2014-12-01

    Selected Saccharomyces cerevisiae strains are used in Brazil to produce the hitherto most energetically efficient first-generation fuel ethanol. Although genome and some transcriptome data are available for some of these strains, quantitative physiological data are lacking. This study investigates the physiology of S. cerevisiae strain PE-2, widely used in the Brazilian fuel ethanol industry, in comparison with CEN.PK113-7D, a reference laboratory strain, focusing on tolerance to low pH and acetic acid stress. Both strains were grown in anaerobic bioreactors, operated as batch, chemostat or dynamic continuous cultures. Despite their different backgrounds, biomass and product formation by the two strains were similar under a range of conditions (pH 5 or pH Yeast extract - Peptone - Dextrose medium at low pH (2.7). Kinetics of viability loss of non-growing cells, incubated at pH 1.5, indicated a superior survival of glucose-depleted PE-2 cells, when compared with either CEN.PK113-7D or a commercial bakers' strain. These results indicate that the sulfuric acid washing step, used in the fuel ethanol industry to decrease bacterial contamination due to non-aseptic operation, might have exerted an important selective pressure on the microbial populations present in such environments. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  10. Context-dependent differences in grooming behavior among the NIH heterogeneous stock and the Roman high- and low-avoidance rats.

    Science.gov (United States)

    Estanislau, C; Díaz-Morán, S; Cañete, T; Blázquez, G; Tobeña, A; Fernández-Teruel, A

    2013-12-01

    Grooming occurs during/after stress and seems to accompany dearousal. Here, grooming was investigated under testing situations involving different levels of aversiveness, taking advantage of differences among three rat strains in fearfulness/anxiety. Inbred Roman High Avoidance (RHA-I) rats are less anxious/fearful than inbred Roman Low Avoidance (RLA-I). The outbred genetically heterogeneous stock of rats (NIH-HS), which resembles the RLA-I in many behavioral traits, was also studied. Adult male rats (RLA-I: n=9, RHA-I: n=10, NIH-HS: n=12) were observed for 30min in: a novel open-field, a novel hole-board and in the home-cage. They were also observed during two-way active avoidance training. Differences in grooming depended on test situation: (a) No differences were found in the home-cage. (b) While tested in a novel environment, RHA-I showed less grooming activity than the other rats. (c) After avoidance responses appeared, differences among the strains were opposite to the observed in novelty tests. Furthermore, results suggest that (i) grooming is mostly suppressed when assured aversive experience is under way; (ii) rostral grooming prevails when experience with aversive stimuli is unpredictable (novelty) or potential (avoidance training); (iii) body grooming increases for a period in novel environments. In general, our results support that grooming takes place during dearousal. Copyright © 2013 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

  11. Ecological Functions of Landscapes

    Science.gov (United States)

    Kiryushin, V. I.

    2018-01-01

    Ecological functions of landscapes are considered a system of processes ensuring the development, preservation, and evolution of ecosystems and the biosphere as a whole. The concept of biogeocenosis can be considered a model that integrates biotic and environmental functions. The most general biogeocenotic functions specify the biodiversity, biotic links, self-organization, and evolution of ecosystems. Close interaction between biocenosis and the biotope (ecotope) is ensured by the continuous exchange of matter, energy, and information. Ecotope determines the biocenosis. The group of ecotopic functions includes atmospheric (gas exchange, heat exchange, hydroatmospheric, climate-forming), lithospheric (geodynamic, geophysical, and geochemical), hydrologic and hydrogeologic functions of landscape and ecotopic functions of soils. Bioecological functions emerge as a result of the biotope and ecotope interaction; these are the bioproductive, destructive, organoaccumulative, biochemical (gas, concentration, redox, biochemical, biopedological), pedogenetic, and energy functions

  12. Functionalized diamond nanoparticles

    KAUST Repository

    Beaujuge, Pierre M.

    2014-10-21

    A diamond nanoparticle can be functionalized with a substituted dienophile under ambient conditions, and in the absence of catalysts or additional reagents. The functionalization is thought to proceed through an addition reaction.

  13. Integrals of Bessel functions

    OpenAIRE

    Babusci, D.; Dattoli, G.; Germano, B.; Martinelli, M. R.; Ricci, P. E.

    2011-01-01

    We use the operator method to evaluate a class of integrals involving Bessel or Bessel-type functions. The technique we propose is based on the formal reduction of these family of functions to Gaussians.

  14. Adding functionality to garments

    CSIR Research Space (South Africa)

    Hunter, L

    2014-11-01

    Full Text Available various functionalities, such as retention of appearance, durability, comfort, handle and tailorability can be enhanced in garments. The tests used to assess and quantify the different functionalities are described....

  15. Smart hydrogel functional materials

    CERN Document Server

    Chu, Liang-Yin; Ju, Xiao-Jie

    2014-01-01

    This book systematically introduces smart hydrogel functional materials with the configurations ranging from hydrogels to microgels. It serves as an excellent reference for designing and fabricating artificial smart hydrogel functional materials.

  16. Functional Python programming

    CERN Document Server

    Lott, Steven

    2015-01-01

    This book is for developers who want to use Python to write programs that lean heavily on functional programming design patterns. You should be comfortable with Python programming, but no knowledge of functional programming paradigms is needed.

  17. and chebyshev functions

    Directory of Open Access Journals (Sweden)

    Mohsen Razzaghi

    2000-01-01

    Full Text Available A direct method for finding the solution of variational problems using a hybrid function is discussed. The hybrid functions which consist of block-pulse functions plus Chebyshev polynomials are introduced. An operational matrix of integration and the integration of the cross product of two hybrid function vectors are presented and are utilized to reduce a variational problem to the solution of an algebraic equation. Illustrative examples are included to demonstrate the validity and applicability of the technique.

  18. Pseudolinear functions and optimization

    CERN Document Server

    Mishra, Shashi Kant

    2015-01-01

    Pseudolinear Functions and Optimization is the first book to focus exclusively on pseudolinear functions, a class of generalized convex functions. It discusses the properties, characterizations, and applications of pseudolinear functions in nonlinear optimization problems.The book describes the characterizations of solution sets of various optimization problems. It examines multiobjective pseudolinear, multiobjective fractional pseudolinear, static minmax pseudolinear, and static minmax fractional pseudolinear optimization problems and their results. The authors extend these results to locally

  19. Degenerate Euler zeta function

    OpenAIRE

    Kim, Taekyun

    2015-01-01

    Recently, T. Kim considered Euler zeta function which interpolates Euler polynomials at negative integer (see [3]). In this paper, we study degenerate Euler zeta function which is holomorphic function on complex s-plane associated with degenerate Euler polynomials at negative integers.

  20. Managing Functional Power

    DEFF Research Database (Denmark)

    Rosenstand, Claus Andreas Foss; Laursen, Per Kyed

    2013-01-01

    How does one manage functional power relations between leading functions in vision driven digital media creation, and this from idea to master during the creation cycle? Functional power is informal, and it is understood as roles, e.g. project manager, that provide opportunities to contribute...

  1. On Functional Calculus Estimates

    NARCIS (Netherlands)

    Schwenninger, F.L.

    2015-01-01

    This thesis presents various results within the field of operator theory that are formulated in estimates for functional calculi. Functional calculus is the general concept of defining operators of the form $f(A)$, where f is a function and $A$ is an operator, typically on a Banach space. Norm

  2. Automatic differentiation of functions

    International Nuclear Information System (INIS)

    Douglas, S.R.

    1990-06-01

    Automatic differentiation is a method of computing derivatives of functions to any order in any number of variables. The functions must be expressible as combinations of elementary functions. When evaluated at specific numerical points, the derivatives have no truncation error and are automatically found. The method is illustrated by simple examples. Source code in FORTRAN is provided

  3. Operations Between Functions

    DEFF Research Database (Denmark)

    Gardner, Richard J.; Kiderlen, Markus

    A structural theory of operations between real-valued (or extended-real-valued) functions on a nonempty subset A of Rn is initiated. It is shown, for example, that any operation ∗ on a cone of functions containing the constant functions, which is pointwise, positively homogeneous, monotonic...

  4. Generating generic functions

    NARCIS (Netherlands)

    Jeuring, J.T.; Rodriquez, A.; Smeding, G.

    2006-01-01

    We present an approach to the generation of generic functions from user-provided specifications. The specifications consist of the type of a generic function, examples of instances that it should “match” when specialized, and properties that the generic function should satisfy. We use the

  5. Phylogenetic molecular function annotation

    International Nuclear Information System (INIS)

    Engelhardt, Barbara E; Jordan, Michael I; Repo, Susanna T; Brenner, Steven E

    2009-01-01

    It is now easier to discover thousands of protein sequences in a new microbial genome than it is to biochemically characterize the specific activity of a single protein of unknown function. The molecular functions of protein sequences have typically been predicted using homology-based computational methods, which rely on the principle that homologous proteins share a similar function. However, some protein families include groups of proteins with different molecular functions. A phylogenetic approach for predicting molecular function (sometimes called 'phylogenomics') is an effective means to predict protein molecular function. These methods incorporate functional evidence from all members of a family that have functional characterizations using the evolutionary history of the protein family to make robust predictions for the uncharacterized proteins. However, they are often difficult to apply on a genome-wide scale because of the time-consuming step of reconstructing the phylogenies of each protein to be annotated. Our automated approach for function annotation using phylogeny, the SIFTER (Statistical Inference of Function Through Evolutionary Relationships) methodology, uses a statistical graphical model to compute the probabilities of molecular functions for unannotated proteins. Our benchmark tests showed that SIFTER provides accurate functional predictions on various protein families, outperforming other available methods.

  6. Expanding Pseudorandom Functions

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Nielsen, Jesper Buus

    2002-01-01

    Given any weak pseudorandom function, we present a general and efficient technique transforming such a function to a new weak pseudorandom function with an arbitrary length output. This implies, among other things, an encryption mode for block ciphers. The mode is as efficient as known (and widely...

  7. Clinical functional MRI. Presurgical functional neuroimaging

    Energy Technology Data Exchange (ETDEWEB)

    Stippich, C. (ed.) [Heidelberg Univ. (Germany). Div. of Neuroradiology

    2007-07-01

    Functional magnetic resonance imaging (fMRI) permits noninvasive imaging of the ''human brain at work'' under physiological conditions. This is the first textbook on clinical fMRI. It is devoted to preoperative fMRI in patients with brain tumors and epilepsies, which are the most well-established clinical applications. By localizing and lateralizing specific brain functions, as well as epileptogenic zones, fMRI facilitates the selection of a safe treatment and the planning and performance of function-preserving neurosurgery. State of the art fMRI procedures are presented, with detailed consideration of the physiological and methodological background, imaging and data processing, normal and pathological findings, diagnostic possibilities and limitations, and other related techniques. All chapters are written by recognized experts in their fields, and the book is designed to be of value to beginners, trained clinicians and experts alike. (orig.)

  8. Nonparametric Transfer Function Models

    Science.gov (United States)

    Liu, Jun M.; Chen, Rong; Yao, Qiwei

    2009-01-01

    In this paper a class of nonparametric transfer function models is proposed to model nonlinear relationships between ‘input’ and ‘output’ time series. The transfer function is smooth with unknown functional forms, and the noise is assumed to be a stationary autoregressive-moving average (ARMA) process. The nonparametric transfer function is estimated jointly with the ARMA parameters. By modeling the correlation in the noise, the transfer function can be estimated more efficiently. The parsimonious ARMA structure improves the estimation efficiency in finite samples. The asymptotic properties of the estimators are investigated. The finite-sample properties are illustrated through simulations and one empirical example. PMID:20628584

  9. Implementing function spreadsheets

    DEFF Research Database (Denmark)

    Sestoft, Peter

    2008-01-01

    : that of turning an expression into a named function. Hence they proposed a way to define a function in terms of a worksheet with designated input and output cells; we shall call it a function sheet. The goal of our work is to develop implementations of function sheets and study their application to realistic...... examples. Therefore, we are also developing a simple yet comprehensive spreadsheet core implementation for experimentation with this technology. Here we report briefly on our experiments with function sheets as well as other uses of our spreadsheet core implementation....

  10. Transfer function combinations

    KAUST Repository

    Zhou, Liang

    2012-10-01

    Direct volume rendering has been an active area of research for over two decades. Transfer function design remains a difficult task since current methods, such as traditional 1D and 2D transfer functions, are not always effective for all data sets. Various 1D or 2D transfer function spaces have been proposed to improve classification exploiting different aspects, such as using the gradient magnitude for boundary location and statistical, occlusion, or size metrics. In this paper, we present a novel transfer function method which can provide more specificity for data classification by combining different transfer function spaces. In this work, a 2D transfer function can be combined with 1D transfer functions which improve the classification. Specifically, we use the traditional 2D scalar/gradient magnitude, 2D statistical, and 2D occlusion spectrum transfer functions and combine these with occlusion and/or size-based transfer functions to provide better specificity. We demonstrate the usefulness of the new method by comparing to the following previous techniques: 2D gradient magnitude, 2D occlusion spectrum, 2D statistical transfer functions and 2D size based transfer functions. © 2012 Elsevier Ltd.

  11. Operator Lipschitz functions

    Science.gov (United States)

    Aleksandrov, A. B.; Peller, V. V.

    2016-08-01

    The goal of this survey is a comprehensive study of operator Lipschitz functions. A continuous function f on the real line {R} is said to be operator Lipschitz if \\Vert f(A)-f(B)\\Vert≤slant{const}\\Vert A-B\\Vert for arbitrary self-adjoint operators A and B. Sufficient conditions and necessary conditions are given for operator Lipschitzness. The class of operator differentiable functions on {R} is also studied. Further, operator Lipschitz functions on closed subsets of the plane are considered, and the class of commutator Lipschitz functions on such subsets is introduced. An important role for the study of such classes of functions is played by double operator integrals and Schur multipliers. Bibliography: 77 titles.

  12. Cryptographic Hash Functions

    DEFF Research Database (Denmark)

    Gauravaram, Praveen; Knudsen, Lars Ramkilde

    2010-01-01

    Cryptographic hash functions are an important tool of cryptography and play a fundamental role in efficient and secure information processing. A hash function processes an arbitrary finite length input message to a fixed length output referred to as the hash value. As a security requirement, a hash...... important applications has also been analysed. This successful cryptanalysis of the standard hash functions has made National Institute of Standards and Technology (NIST), USA to initiate an international public competition to select the most secure and efficient hash function as the future hash function...... value should not serve as an image for two distinct input messages and it should be difficult to find the input message from a given hash value. Secure hash functions serve data integrity, non-repudiation and authenticity of the source in conjunction with the digital signature schemes. Keyed hash...

  13. Pair Correlation Function Integrals

    DEFF Research Database (Denmark)

    Wedberg, Nils Hejle Rasmus Ingemar; O'Connell, John P.; Peters, Günther H.J.

    2011-01-01

    We describe a method for extending radial distribution functions obtained from molecular simulations of pure and mixed molecular fluids to arbitrary distances. The method allows total correlation function integrals to be reliably calculated from simulations of relatively small systems. The long-d...... distribution function has structure beyond the sampling limit imposed by the system size, the integration is more reliable, and usually more accurate, than simple integral truncation.......We describe a method for extending radial distribution functions obtained from molecular simulations of pure and mixed molecular fluids to arbitrary distances. The method allows total correlation function integrals to be reliably calculated from simulations of relatively small systems. The long......, and J. Abildskov, Mol. Simul. 36, 1243 (2010); Fluid Phase Equilib. 302, 32 (2011)], but describe here its theoretical basis more thoroughly and derive long-distance approximations for the direct correlation functions. We describe the numerical implementation of the method in detail, and report...

  14. Time functions revisited

    Science.gov (United States)

    Fathi, Albert

    2015-07-01

    In this paper we revisit our joint work with Antonio Siconolfi on time functions. We will give a brief introduction to the subject. We will then show how to construct a Lipschitz time function in a simplified setting. We will end with a new result showing that the Aubry set is not an artifact of our proof of existence of time functions for stably causal manifolds.

  15. SPLINE, Spline Interpolation Function

    International Nuclear Information System (INIS)

    Allouard, Y.

    1977-01-01

    1 - Nature of physical problem solved: The problem is to obtain an interpolated function, as smooth as possible, that passes through given points. The derivatives of these functions are continuous up to the (2Q-1) order. The program consists of the following two subprograms: ASPLERQ. Transport of relations method for the spline functions of interpolation. SPLQ. Spline interpolation. 2 - Method of solution: The methods are described in the reference under item 10

  16. Functional Programming With Relations

    OpenAIRE

    Hutton, Graham

    1991-01-01

    While programming in a relational framework has much to offer over the functional style in terms of expressiveness, computing with relations is less efficient, and more semantically troublesome. In this paper we propose a novel blend of the functional and relational styles. We identify a class of "causal relations", which inherit some of the bi-directionality properties of relations, but retain the efficiency and semantic foundations of the functional style.

  17. Photon structure function

    International Nuclear Information System (INIS)

    Bardeen, W.A.

    1980-11-01

    Theoretical understanding of the photon structure function is reviewed. As an illustration of the pointlike component, the parton model is briefly discussed. However, the systematic study of the photon structure function is presented through the framework of the operator product expansion. Perturbative QCD is used as the theoretical basis for the calculation of leading contributions to the operator product expansion. The influence of higher order QCD effects on these results is discussed. Recent results for the polarized structure functions are discussed

  18. Diffusion of responsibility attenuates altruistic punishment: A functional magnetic resonance imaging effective connectivity study.

    Science.gov (United States)

    Feng, Chunliang; Deshpande, Gopikrishna; Liu, Chao; Gu, Ruolei; Luo, Yue-Jia; Krueger, Frank

    2016-02-01

    Humans altruistically punish violators of social norms to enforce cooperation and pro-social behaviors. However, such altruistic behaviors diminish when others are present, due to a diffusion of responsibility. We investigated the neural signatures underlying the modulations of diffusion of responsibility on altruistic punishment, conjoining a third-party punishment task with event-related functional magnetic resonance imaging and multivariate Granger causality mapping. In our study, participants acted as impartial third-party decision-makers and decided how to punish norm violations under two different social contexts: alone (i.e., full responsibility) or in the presence of putative other third-party decision makers (i.e., diffused responsibility). Our behavioral results demonstrated that the diffusion of responsibility served as a mediator of context-dependent punishment. In the presence of putative others, participants who felt less responsible also punished less severely in response to norm violations. Our neural results revealed that underlying this behavioral effect was a network of interconnected brain regions. For unfair relative to fair splits, the presence of others led to attenuated responses in brain regions implicated in signaling norm violations (e.g., AI) and to increased responses in brain regions implicated in calculating values of norm violations (e.g., vmPFC, precuneus) and mentalizing about others (dmPFC). The dmPFC acted as the driver of the punishment network, modulating target regions, such as AI, vmPFC, and precuneus, to adjust altruistic punishment behavior. Our results uncovered the neural basis of the influence of diffusion of responsibility on altruistic punishment and highlighted the role of the mentalizing network in this important phenomenon. Hum Brain Mapp 37:663-677, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  19. Turtle functions downstream of Cut in differentially regulating class specific dendrite morphogenesis in Drosophila.

    Directory of Open Access Journals (Sweden)

    Mikolaj J Sulkowski

    Full Text Available Dendritic morphology largely determines patterns of synaptic connectivity and electrochemical properties of a neuron. Neurons display a myriad diversity of dendritic geometries which serve as a basis for functional classification. Several types of molecules have recently been identified which regulate dendrite morphology by acting at the levels of transcriptional regulation, direct interactions with the cytoskeleton and organelles, and cell surface interactions. Although there has been substantial progress in understanding the molecular mechanisms of dendrite morphogenesis, the specification of class-specific dendritic arbors remains largely unexplained. Furthermore, the presence of numerous regulators suggests that they must work in concert. However, presently, few genetic pathways regulating dendrite development have been defined.The Drosophila gene turtle belongs to an evolutionarily conserved class of immunoglobulin superfamily members found in the nervous systems of diverse organisms. We demonstrate that Turtle is differentially expressed in Drosophila da neurons. Moreover, MARCM analyses reveal Turtle acts cell autonomously to exert class specific effects on dendritic growth and/or branching in da neuron subclasses. Using transgenic overexpression of different Turtle isoforms, we find context-dependent, isoform-specific effects on mediating dendritic branching in class II, III and IV da neurons. Finally, we demonstrate via chromatin immunoprecipitation, qPCR, and immunohistochemistry analyses that Turtle expression is positively regulated by the Cut homeodomain transcription factor and via genetic interaction studies that Turtle is downstream effector of Cut-mediated regulation of da neuron dendrite morphology.Our findings reveal that Turtle proteins differentially regulate the acquisition of class-specific dendrite morphologies. In addition, we have established a transcriptional regulatory interaction between Cut and Turtle, representing

  20. Normal Functions as a New Way of Defining Computable Functions

    Directory of Open Access Journals (Sweden)

    Leszek Dubiel

    2004-01-01

    Full Text Available Report sets new method of defining computable functions. This is formalization of traditional function descriptions, so it allows to define functions in very intuitive way. Discovery of Ackermann function proved that not all functions that can be easily computed can be so easily described with Hilbert's system of recursive functions. Normal functions lack this disadvantage.

  1. Normal Functions As A New Way Of Defining Computable Functions

    Directory of Open Access Journals (Sweden)

    Leszek Dubiel

    2004-01-01

    Full Text Available Report sets new method of defining computable functions. This is formalization of traditional function descriptions, so it allows to define functions in very intuitive way. Discovery of Ackermann function proved that not all functions that can be easily computed can be so easily described with Hilbert’s system of recursive functions. Normal functions lack this disadvantage.

  2. The gamma function

    CERN Document Server

    Artin, Emil

    2015-01-01

    This brief monograph on the gamma function was designed by the author to fill what he perceived as a gap in the literature of mathematics, which often treated the gamma function in a manner he described as both sketchy and overly complicated. Author Emil Artin, one of the twentieth century's leading mathematicians, wrote in his Preface to this book, ""I feel that this monograph will help to show that the gamma function can be thought of as one of the elementary functions, and that all of its basic properties can be established using elementary methods of the calculus."" Generations of teachers

  3. Coded Network Function Virtualization

    DEFF Research Database (Denmark)

    Al-Shuwaili, A.; Simone, O.; Kliewer, J.

    2016-01-01

    Network function virtualization (NFV) prescribes the instantiation of network functions on general-purpose network devices, such as servers and switches. While yielding a more flexible and cost-effective network architecture, NFV is potentially limited by the fact that commercial off-the-shelf ha......Network function virtualization (NFV) prescribes the instantiation of network functions on general-purpose network devices, such as servers and switches. While yielding a more flexible and cost-effective network architecture, NFV is potentially limited by the fact that commercial off...

  4. Perceptual Audio Hashing Functions

    Directory of Open Access Journals (Sweden)

    Emin Anarım

    2005-07-01

    Full Text Available Perceptual hash functions provide a tool for fast and reliable identification of content. We present new audio hash functions based on summarization of the time-frequency spectral characteristics of an audio document. The proposed hash functions are based on the periodicity series of the fundamental frequency and on singular-value description of the cepstral frequencies. They are found, on one hand, to perform very satisfactorily in identification and verification tests, and on the other hand, to be very resilient to a large variety of attacks. Moreover, we address the issue of security of hashes and propose a keying technique, and thereby a key-dependent hash function.

  5. Nonrespiratory lung function

    International Nuclear Information System (INIS)

    Isawa, Toyoharu

    1994-01-01

    The function of the lungs is primarily the function as a gas exchanger: the venous blood returning to the lungs is arterialized with oxygen in the lungs and the arterialized blood is sent back again to the peripheral tissues of the whole body to be utilized for metabolic oxygenation. Besides the gas exchanging function which we call ''respiratory lung function'' the lungs have functions that have little to do with gas exchange itself. We categorically call the latter function of the lungs as ''nonrespiratory lung function''. The lungs consist of the conductive airways, the gas exchanging units like the alveoli, and the interstitial space that surrounds the former two compartments. The interstitial space contains the blood and lymphatic capillaries, collagen and elastic fibers and cement substances. The conductive airways and the gas exchanging units are directly exposed to the atmosphere that contains various toxic and nontoxic gases, fume and biological or nonbiological particles. Because the conductive airways are equipped with defense mechanisms like mucociliary clearance or coughs to get rid of these toxic gases, particles or locally produced biological debris, we are usually free from being succumbed to ill effects of inhaled materials. By use of nuclear medicine techniques, we can now evaluate mucociliary clearance function, and other nonrespiratory lung functions as well in vivo

  6. Control functions in MFM

    DEFF Research Database (Denmark)

    Lind, Morten

    2011-01-01

    Multilevel Flow Modeling (MFM) has been proposed as a tool for representing goals and functions of complex industrial plants and suggested as a basis for reasoning about control situations. Lind presents an introduction to MFM but do not describe how control functions are used in the modeling....... The purpose of the present paper is to serve as a companion paper to this introduction by explaining the basic principles used in MFM for representation of control functions. A theoretical foundation for modeling control functions is presented and modeling examples are given for illustration....

  7. Subordination by convex functions

    Directory of Open Access Journals (Sweden)

    Rosihan M. Ali

    2006-01-01

    Full Text Available For a fixed analytic function g(z=z+∑n=2∞gnzn defined on the open unit disk and γ<1, let Tg(γ denote the class of all analytic functions f(z=z+∑n=2∞anzn satisfying ∑n=2∞|angn|≤1−γ. For functions in Tg(γ, a subordination result is derived involving the convolution with a normalized convex function. Our result includes as special cases several earlier works.

  8. Autism and the weak central coherence theory. Investigations with functional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Manjaly, Z.M.

    2007-10-01

    The contribution covers the following chapters: 1. In search of the hidden: an FMRI study with implications for the study of patients with autism and with acquired brain injury. 2. Context-dependent interactions of left posterior inferior frontal gyrus in a local visual search task unrelated to language. 3. Neurophysiological correlates of relatively enhanced local visual search in autistic adolescents

  9. Autism and the weak central coherence theory. Investigations with functional magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Manjaly, Z.M.

    2007-10-15

    The contribution covers the following chapters: 1. In search of the hidden: an FMRI study with implications for the study of patients with autism and with acquired brain injury. 2. Context-dependent interactions of left posterior inferior frontal gyrus in a local visual search task unrelated to language. 3. Neurophysiological correlates of relatively enhanced local visual search in autistic adolescents.

  10. Memory contextualization: The role of prefrontal cortex in functional integration across item and context representational regions

    NARCIS (Netherlands)

    Zhang, W.; Ast, V.A. van; Klumpers, F.; Roelofs, K.; Hermans, E.

    2018-01-01

    Memory recall is facilitated when retrieval occurs in the original encoding context. This context dependency effect likely results from the automatic binding of central elements of an experience with contextual features (i.e., memory "contextualization") during encoding. However, despite a vast body

  11. Mapping Cognitive Function

    OpenAIRE

    Stufflebeam, Steven M.; Rosen, Bruce

    2007-01-01

    Cognitive functions are fundamental to being human. Although tremendous progress has been made in the science of cognition using neuroimaging, the clinical applications of neuroimaging are just beginning to be realized. A unifying theme of this chapter is the concept that a more complete understanding of cognition only comes through integration of multimodal structural and functional imaging technologies.

  12. Photon strength functions

    International Nuclear Information System (INIS)

    Bergqvist, I.

    1976-01-01

    Methods for extracting photon strength functions are briefly discussed. We follow the Brink-Axel approach to relate the strength functions to the giant resonances observed in photonuclear work and summarize the available data on the E1, E2 and M1 resonances. Some experimental and theoretical problems are outlined. (author)

  13. Marine functional food

    NARCIS (Netherlands)

    Luten, J.B.

    2009-01-01

    This book reviews the research on seafood and health, the use and quality aspects of marine lipids and seafood proteins as ingredients in functional foods and consumer acceptance of (marine) functional food. The first chapter covers novel merging areas where seafood may prevent disease and improve

  14. Functional Magnetic Resonance Imaging

    Science.gov (United States)

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  15. Who Researches Functional Literacy?

    Science.gov (United States)

    Shaw, Donita; Perry, Kristen H.; Ivanyuk, Lyudmyla; Tham, Sarah

    2017-01-01

    The purpose of our study was to discover who researches functional literacy. This study was situated within a larger systematic literature review. We searched seven electronic databases and identified 90 sources to answer our larger question regarding how functional literacy is defined and conceptualized as well as the specific question pertinent…

  16. Functional foods innovations

    Science.gov (United States)

    The aim of the Dairy and Functional Foods Research Unit (DFFRU), ERRC, ARS, USDA, is to improve human health and well being by developing functional food and consumer products that utilize milk and fruit and vegetable processing residues of specialty crops. Major research approaches involve: biotec...

  17. New Similarity Functions

    DEFF Research Database (Denmark)

    Yazdani, Hossein; Ortiz-Arroyo, Daniel; Kwasnicka, Halina

    2016-01-01

    In data science, there are important parameters that affect the accuracy of the algorithms used. Some of these parameters are: the type of data objects, the membership assignments, and distance or similarity functions. This paper discusses similarity functions as fundamental elements in membership...

  18. Functional polymer amphiphiles

    NARCIS (Netherlands)

    Loos, Femke de

    2009-01-01

    'The exact structures of large, biologically interesting molecules such as proteins are very important for the functions these molecules fulfill. In order to increase our understanding of the relationship between structure and function and to enhance the predictive power of theoretical models the

  19. Bandlimited Lipschitz functions

    OpenAIRE

    Lyubarskii, Yurii; Ortega Cerdà, Joaquim

    2014-01-01

    We study the space of bandlimited Lipschitz functions in one variable. In particular we provide a geometrical description of the natural interpolating and sampling sequences for this space. We also find a description of the trace of such functions to sequences of critical density in terms of a cancellation condition.

  20. Neurophysiology of functional imaging

    NARCIS (Netherlands)

    van Eijsden, Pieter; Hyder, Fahmeed; Rothman, Douglas L.; Shulman, Robert G.

    2009-01-01

    The successes of PET and fMRI in non-invasively localizing sensory functions had encouraged efforts to transform the subjective concepts of cognitive psychology into objective physical measures. The assumption was that mental functions could be decomposed into non-overlapping, context-independent

  1. Function spaces, 1

    CERN Document Server

    Pick, Luboš; John, Oldrich; Fucík, Svatopluk

    2012-01-01

    This is the first part of the second revised and extended edition of a well established monograph. It is an introduction to function spaces defined in terms of differentiability and integrability classes. It provides a catalogue of various spaces and benefits as a handbook for those who use function spaces to study other topics such as partial differential equations. Volum

  2. Functional Discourse Grammar

    NARCIS (Netherlands)

    Hengeveld, K.; Mackenzie, J.L.; Heine, B.; Narrog, H.

    2010-01-01

    Functional Discourse Grammar (FDG) is a typologically based structural-functional theory of language. It has a top-down organization to achieve psychological adequacy, and takes the Discourse Act as its basic unit of analysis to achieve pragmatic adequacy. Although itself strictly a model of

  3. The Functional C Experience

    NARCIS (Netherlands)

    Hartel, Pieter H.; Muller, Henk; Glaser, Hugh

    A functional programming language can be taught successfully as a First language, but if there is no follow up the students do not appreciate the functional approach. Following discussions concerning this issue at the 1995 FPLE conf. we decided to develop such a follow up by writing a book that

  4. Functional sensory symptoms

    NARCIS (Netherlands)

    Stone, J.; Vermeulen, M.

    2017-01-01

    Functional (psychogenic) sensory symptoms are those in which the patient genuinely experiences alteration or absence of normal sensation in the absence of neurologic disease. The hallmark of functional sensory symptoms is the presence of internal inconsistency revealing a pattern of symptoms

  5. A phased translation function

    International Nuclear Information System (INIS)

    Read, R.J.; Schierbeek, A.J.

    1988-01-01

    A phased translation function, which takes advantage of prior phase information to determine the position of an oriented mulecular replacement model, is examined. The function is the coefficient of correlation between the electron density computed with the prior phases and the electron density of the translated model, evaluated in reciprocal space as a Fourier transform. The correlation coefficient used in this work is closely related to an overlap function devised by Colman, Fehlhammer and Bartels. Tests with two protein structures, one of which was solved with the help of the phased translation function, show that little phase information is required to resolve the translation problem, and that the function is relatively insensitive to misorientation of the model. (orig.)

  6. Functional data analysis

    CERN Document Server

    Ramsay, J O

    1997-01-01

    Scientists today collect samples of curves and other functional observations. This monograph presents many ideas and techniques for such data. Included are expressions in the functional domain of such classics as linear regression, principal components analysis, linear modelling, and canonical correlation analysis, as well as specifically functional techniques such as curve registration and principal differential analysis. Data arising in real applications are used throughout for both motivation and illustration, showing how functional approaches allow us to see new things, especially by exploiting the smoothness of the processes generating the data. The data sets exemplify the wide scope of functional data analysis; they are drwan from growth analysis, meterology, biomechanics, equine science, economics, and medicine. The book presents novel statistical technology while keeping the mathematical level widely accessible. It is designed to appeal to students, to applied data analysts, and to experienced researc...

  7. On complex functions analyticity

    CERN Document Server

    Karavashkin, S B

    2002-01-01

    We analyse here the conventional definitions of analyticity and differentiability of functions of complex variable. We reveal the possibility to extend the conditions of analyticity and differentiability to the functions implementing the non-conformal mapping. On this basis we formulate more general definitions of analyticity and differentiability covering those conventional. We present some examples of such functions. By the example of a horizontal belt on a plane Z mapped non-conformally onto a crater-like harmonic vortex, we study the pattern of trajectory variation of a body motion in such field in case of field power function varying in time. We present the technique to solve the problems of such type with the help of dynamical functions of complex variable implementing the analytical non-conformal mapping

  8. A Functional HAZOP Methodology

    DEFF Research Database (Denmark)

    Liin, Netta; Lind, Morten; Jensen, Niels

    2010-01-01

    A HAZOP methodology is presented where a functional plant model assists in a goal oriented decomposition of the plant purpose into the means of achieving the purpose. This approach leads to nodes with simple functions from which the selection of process and deviation variables follow directly....... The functional HAZOP methodology lends itself directly for implementation into a computer aided reasoning tool to perform root cause and consequence analysis. Such a tool can facilitate finding causes and/or consequences far away from the site of the deviation. A functional HAZOP assistant is proposed...... and investigated in a HAZOP study of an industrial scale Indirect Vapor Recompression Distillation pilot Plant (IVaRDiP) at DTU-Chemical and Biochemical Engineering. The study shows that the functional HAZOP methodology provides a very efficient paradigm for facilitating HAZOP studies and for enabling reasoning...

  9. properties and luminosity functions

    Directory of Open Access Journals (Sweden)

    Hektor Monteiro

    2007-01-01

    Full Text Available In this article, we present an investigation of a sample of 1072 stars extracted from the Villanova Catalog of Spectroscopically Identified White Dwarfs (2005 on-line version, studying their distribution in the Galaxy, their physical properties and their luminosity functions. The distances and physical properties of the white dwarfs are determined through interpolation of their (B-V or (b-y colors in model grids. The solar position relative to the Galactic plane, luminosity function, as well as separate functions for each white dwarf spectral type are derived and discussed. We show that the binary fraction does not vary significantly as a function of distance from the Galactic disk out to 100 pc. We propose that the formation rates of DA and non-DAs have changed over time and/or that DAs evolve into non-DA types. The luminosity functions for DAs and DBs have peaks possibly related to a star burst event.

  10. Time Functions as Utilities

    Science.gov (United States)

    Minguzzi, E.

    2010-09-01

    Every time function on spacetime gives a (continuous) total preordering of the spacetime events which respects the notion of causal precedence. The problem of the existence of a (semi-)time function on spacetime and the problem of recovering the causal structure starting from the set of time functions are studied. It is pointed out that these problems have an analog in the field of microeconomics known as utility theory. In a chronological spacetime the semi-time functions correspond to the utilities for the chronological relation, while in a K-causal (stably causal) spacetime the time functions correspond to the utilities for the K + relation (Seifert’s relation). By exploiting this analogy, we are able to import some mathematical results, most notably Peleg’s and Levin’s theorems, to the spacetime framework. As a consequence, we prove that a K-causal (i.e. stably causal) spacetime admits a time function and that the time or temporal functions can be used to recover the K + (or Seifert) relation which indeed turns out to be the intersection of the time or temporal orderings. This result tells us in which circumstances it is possible to recover the chronological or causal relation starting from the set of time or temporal functions allowed by the spacetime. Moreover, it is proved that a chronological spacetime in which the closure of the causal relation is transitive (for instance a reflective spacetime) admits a semi-time function. Along the way a new proof avoiding smoothing techniques is given that the existence of a time function implies stable causality, and a new short proof of the equivalence between K-causality and stable causality is given which takes advantage of Levin’s theorem and smoothing techniques.

  11. Mapping cognitive function.

    Science.gov (United States)

    Stufflebeam, Steven M; Rosen, Bruce R

    2007-11-01

    Cognitive functions are fundamental to being human. Although tremendous progress has been made in the science of cognition using neuroimaging, the clinical applications of neuroimaging are just beginning to be realized. This article focuses on selected technologies, analysis techniques, and applications that have, or will soon have, direct clinical impact. The authors discuss how cognition can be imaged using MR imaging, functional MR imaging, positron emission tomography, magnetoencephalography and electroencephalography, and MR imaging diffusion tensor imaging. A unifying theme of this article is the concept that a more complete understanding of cognition only comes through integration of multimodal structural and functional imaging technologies.

  12. Functional Amyloids in Reproduction.

    Science.gov (United States)

    Hewetson, Aveline; Do, Hoa Quynh; Myers, Caitlyn; Muthusubramanian, Archana; Sutton, Roger Bryan; Wylie, Benjamin J; Cornwall, Gail A

    2017-06-29

    Amyloids are traditionally considered pathological protein aggregates that play causative roles in neurodegenerative disease, diabetes and prionopathies. However, increasing evidence indicates that in many biological systems nonpathological amyloids are formed for functional purposes. In this review, we will specifically describe amyloids that carry out biological roles in sexual reproduction including the processes of gametogenesis, germline specification, sperm maturation and fertilization. Several of these functional amyloids are evolutionarily conserved across several taxa, including human, emphasizing the critical role amyloids perform in reproduction. Evidence will also be presented suggesting that, if altered, some functional amyloids may become pathological.

  13. Harmonic oscillator Green's function

    International Nuclear Information System (INIS)

    Macek, J.H.; Ovchinnikov, S.Yu.; Khrebtukov, D.B.

    2000-01-01

    The Green's function for the harmonic oscillator in three dimensions plays an important role in the theory of atomic collisions. One representation of low-energy ion-atom collisions involves harmonic oscillator potentials. A closed-form expression for the harmonic oscillator Green's function, needed to exploit this representation, is derived. This expression is similar to the expression for the Coulomb Green's function obtained by Hostler and Pratt. Calculations of electron distributions for a model system of ion-atom collisions are reported to illustrate the theory.

  14. Functionalized expanded porphyrins

    Science.gov (United States)

    Sessler, Jonathan L; Pantos, Patricia J

    2013-11-12

    Disclosed are functionalized expanded porphyrins that can be used as spectrometric sensors for high-valent actinide cations. The disclosed functionalized expanded porphyrins have the advantage over unfunctionalized systems in that they can be immobilized via covalent attachment to a solid support comprising an inorganic or organic polymer or other common substrates. Substrates comprising the disclosed functionalized expanded porphyrins are also disclosed. Further, disclosed are methods of making the disclosed compounds (immobilized and free), methods of using them as sensors to detect high valent actinides, devices that comprise the disclosed compounds, and kits.

  15. Polysheroidal periodic functions

    International Nuclear Information System (INIS)

    Truskova, N.F.

    1985-01-01

    Separation of variables in the Helmholtz N-dimensional (N≥4) equation in polyspheroidal coordinate systems leads to the necessity of solving equations going over into equations for polyspheroidal periodic functions used for solving the two-centre problem in quantum mechanics, the three-body problem with Coulomb interaction, etc. For these functions the expansions are derived in terms of the Jacobi polynomials and Bessel functions. Their basic properties, asymptotics are considered. The algorithm of their computer calculations is developed. The results of numerical calculations are given

  16. Choice probability generating functions

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; McFadden, Daniel; Bierlaire, Michel

    2010-01-01

    This paper establishes that every random utility discrete choice model (RUM) has a representation that can be characterized by a choice-probability generating function (CPGF) with specific properties, and that every function with these specific properties is consistent with a RUM. The choice...... probabilities from the RUM are obtained from the gradient of the CPGF. Mixtures of RUM are characterized by logarithmic mixtures of their associated CPGF. The paper relates CPGF to multivariate extreme value distributions, and reviews and extends methods for constructing generating functions for applications...

  17. Skin barrier function

    DEFF Research Database (Denmark)

    2016-01-01

    barrier integrity, factors influencing the penetration of the skin, influence of wet work, and guidance for prevention and saving the barrier. Distinguished researchers have contributed to this book, providing a comprehensive and thorough overview of the skin barrier function. Researchers in the field...... on the subject. It covers new basic research on skin markers, including results on filaggrin and on methods for the assessment of the barrier function. Biological variation and aspects of skin barrier function restoration are discussed as well. Further sections are dedicated to clinical implications of skin...

  18. Increased functional connectivity between superior colliculus and brain regions implicated in bodily self-consciousness during the rubber hand illusion.

    Science.gov (United States)

    Olivé, Isadora; Tempelmann, Claus; Berthoz, Alain; Heinze, Hans-Joachim

    2015-02-01

    Bodily self-consciousness refers to bodily processes operating at personal, peripersonal, and extrapersonal spatial dimensions. Although the neural underpinnings of representations of personal and peripersonal space associated with bodily self-consciousness were thoroughly investigated, relatively few is known about the neural underpinnings of representations of extrapersonal space relevant for bodily self-consciousness. In the search to unravel brain structures generating a representation of the extrapersonal space relevant for bodily self-consciousness, we developed a functional magnetic resonance imaging (fMRI) study to investigate the implication of the superior colliculus (SC) in bodily illusions, and more specifically in the rubber hand illusion (RHi), which constitutes an established paradigm to study the neural underpinnings of bodily self-consciousness. We observed activation of the colliculus ipsilateral to the manipulated hand associated with eliciting of RHi. A generalized form of context-dependent psychophysiological interaction analysis unravelled increased illusion-dependent functional connectivity between the SC and some of the main brain areas previously involved in bodily self-consciousness: right temporoparietal junction (rTPJ), bilateral ventral premotor cortex (vPM), and bilateral postcentral gyrus. We hypothesize that the collicular map of the extrapersonal space interacts with maps of the peripersonal and personal space generated at rTPJ, vPM and the postcentral gyrus, producing a unified representation of space that is relevant for bodily self-consciousness. We suggest that processes of multisensory integration of bodily-related sensory inputs located in this unified representation of space constitute one main factor underpinning emergence of bodily self-consciousness. © 2014 Wiley Periodicals, Inc.

  19. Lectures on Functional Analysis

    CERN Document Server

    Kurepa, Svetozar; Kraljević, Hrvoje

    1987-01-01

    This volume consists of a long monographic paper by J. Hoffmann-Jorgensen and a number of shorter research papers and survey articles covering different aspects of functional analysis and its application to probability theory and differential equations.

  20. Introduction to structure functions

    International Nuclear Information System (INIS)

    Kwiecinski, J.

    1996-07-01

    The theory of deep inelastic scattering structure functions is reviewed with an emphasis put on the QCD expectations of their behaviour in the region of small values of Bjorken parameter x. (author). 56 refs

  1. Reasoning about Function Objects

    Science.gov (United States)

    Nordio, Martin; Calcagno, Cristiano; Meyer, Bertrand; Müller, Peter; Tschannen, Julian

    Modern object-oriented languages support higher-order implementations through function objects such as delegates in C#, agents in Eiffel, or closures in Scala. Function objects bring a new level of abstraction to the object-oriented programming model, and require a comparable extension to specification and verification techniques. We introduce a verification methodology that extends function objects with auxiliary side-effect free (pure) methods to model logical artifacts: preconditions, postconditions and modifies clauses. These pure methods can be used to specify client code abstractly, that is, independently from specific instantiations of the function objects. To demonstrate the feasibility of our approach, we have implemented an automatic prover, which verifies several non-trivial examples.

  2. Functional Use Database (FUse)

    Data.gov (United States)

    U.S. Environmental Protection Agency — There are five different files for this dataset: 1. A dataset listing the reported functional uses of chemicals (FUse) 2. All 729 ToxPrint descriptors obtained from...

  3. Catalytic Functions of Standards

    NARCIS (Netherlands)

    K. Blind (Knut)

    2009-01-01

    textabstractThe three different areas and the examples have illustrated several catalytic functions of standards for innovation. First, the standardisation process reduces the time to market of inventions, research results and innovative technologies. Second, standards themselves promote the

  4. Contributing to Functionality

    DEFF Research Database (Denmark)

    Törpel, Bettina

    2006-01-01

    advocated in this paper, emerges in the specific dynamic interplay of actors, objectives, structures, practices and means. In this view, functionality is the result of creating, harnessing and inhabiting computer supported joint action spaces. The successful creation and further development of a computer......The objective of this paper is the design of computer supported joint action spaces. It is argued against a view of functionality as residing in computer applications. In such a view the creation of functionality is equivalent to the creation of computer applications. Functionality, in the view...... supported joint action space comprises a whole range of appropriate design contributions. The approach is illustrated by the example of the creation of the computer supported joint action space "exchange network of voluntary union educators". As part of the effort a group of participants created...

  5. Fundamentals of functional analysis

    CERN Document Server

    Farenick, Douglas

    2016-01-01

    This book provides a unique path for graduate or advanced undergraduate students to begin studying the rich subject of functional analysis with fewer prerequisites than is normally required. The text begins with a self-contained and highly efficient introduction to topology and measure theory, which focuses on the essential notions required for the study of functional analysis, and which are often buried within full-length overviews of the subjects. This is particularly useful for those in applied mathematics, engineering, or physics who need to have a firm grasp of functional analysis, but not necessarily some of the more abstruse aspects of topology and measure theory normally encountered. The reader is assumed to only have knowledge of basic real analysis, complex analysis, and algebra. The latter part of the text provides an outstanding treatment of Banach space theory and operator theory, covering topics not usually found together in other books on functional analysis. Written in a clear, concise manner,...

  6. Center for Functional Nanomaterials

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for Functional Nanomaterials (CFN) explores the unique properties of materials and processes at the nanoscale. The CFN is a user-oriented research center...

  7. Assessment of splenic function

    NARCIS (Netherlands)

    de Porto, A.P.N.A.; Lammers, A.J.J.; Bennink, R.J.; ten Berge, R.J.M.; Speelman, P.; Hoekstra, J.B.L.

    2010-01-01

    Hyposplenic patients are at risk of overwhelming post-splenectomy infection (OPSI), which carries mortality of up to 70%. Therefore, preventive measures are warranted. However, patients with diminished splenic function are difficult to identify. In this review we discuss immunological,

  8. Haskell_#: Coordinating Functional Processes

    OpenAIRE

    Junior, Francisco Heron de Carvalho; Lins, Rafael Dueire

    2012-01-01

    This paper presents Haskell#, a coordination language targeted at the efficient implementation of parallel scientific applications on loosely coupled parallel architectures, using the functional language Haskell. Examples of applications, their implementation details and performance figures are presented.

  9. Normal Functioning Family

    Science.gov (United States)

    ... Spread the Word Shop AAP Find a Pediatrician Family Life Medical Home Family Dynamics Adoption & Foster Care ... Español Text Size Email Print Share Normal Functioning Family Page Content Article Body Is there any way ...

  10. Characterisation of Functional Surfaces

    DEFF Research Database (Denmark)

    Lonardo, P.M.; De Chiffre, Leonardo; Bruzzone, A.A.

    2004-01-01

    Characterisation of surfaces is of fundamental importance to control the manufacturing process and the functional performance of the part. Many applications concern contact and tribology problems, which include friction, wear and lubrication. This paper presents the techniques and instruments for...

  11. Safety performance functions.

    Science.gov (United States)

    2014-10-01

    This project developed safety performance functions for roadway segments and intersections for two-lane rural highways in : Pennsylvania. The statistical modeling methodology was consistent with that used in the first edition of the American : Associ...

  12. Smooth functions statistics

    International Nuclear Information System (INIS)

    Arnold, V.I.

    2006-03-01

    To describe the topological structure of a real smooth function one associates to it the graph, formed by the topological variety, whose points are the connected components of the level hypersurface of the function. For a Morse function, such a graph is a tree. Generically, it has T triple vertices, T + 2 endpoints, 2T + 2 vertices and 2T + 1 arrows. The main goal of the present paper is to study the statistics of the graphs, corresponding to T triple points: what is the growth rate of the number φ(T) of different graphs? Which part of these graphs is representable by the polynomial functions of corresponding degree? A generic polynomial of degree n has at most (n - 1) 2 critical points on R 2 , corresponding to 2T + 2 = (n - 1) 2 + 1, that is to T = 2k(k - 1) saddle-points for degree n = 2k

  13. Degenerate Gauss hypergeometric functions

    OpenAIRE

    Vidunas, Raimundas

    2004-01-01

    This is a study of terminating and ill-defined Gauss hypergeometric functions. Corresponding hypergeometric equations have a degenerate set of of 24 Kummer's solutions. We describe those solutions and relations between them.

  14. MATLAB: Creating Functions

    OpenAIRE

    2003-01-01

    sim tut Simulation Tutorial Interactive Media Element This interactive tutorial on MATLAB covers the following: Create M-files, scripts, and functions., Write HELP comments for the functions., Determine the order in which MATLAB chooses to execute entities with identical names.The interactions involve entering MATLAB instructions and observing the outcomes. Self-check questions are provided to help learners determine their level of understanding of the content presented. EC1...

  15. On Transcendental Functions

    Indian Academy of Sciences (India)

    Functions like loge X, eX, x real, and eZ loge Z, Z complex are very important in mathematics and physics. The re- sults in this article are not new, but they are presented in a very natural way. It is observed that eZ is the one and only one complex analytic extension of the real analytic function eX with the preservation of ...

  16. Production Functions Behaving Badly

    DEFF Research Database (Denmark)

    Fredholm, Thomas

    This paper reconsiders Anwar Shaikh's critique of the neoclassical theory of growth and distribution based on its use of aggregate production functions. This is done by reconstructing and extending Franklin M. Fisher's 1971 computer simulations, which Shaikh used to support his critique. Together...... with other recent extensions to Shaikh's seminal work, my results support and strengthen the evidence against the use of aggregate production functions....

  17. Applied functional analysis

    CERN Document Server

    Griffel, DH

    2002-01-01

    A stimulating introductory text, this volume examines many important applications of functional analysis to mechanics, fluid mechanics, diffusive growth, and approximation. Detailed enough to impart a thorough understanding, the text is also sufficiently straightforward for those unfamiliar with abstract analysis. Its four-part treatment begins with distribution theory and discussions of Green's functions. Essentially independent of the preceding material, the second and third parts deal with Banach spaces, Hilbert space, spectral theory, and variational techniques. The final part outlines the

  18. Inequalities for Humbert functions

    Directory of Open Access Journals (Sweden)

    Ayman Shehata

    2014-04-01

    Full Text Available This paper is motivated by an open problem of Luke’s theorem. We consider the problem of developing a unified point of view on the theory of inequalities of Humbert functions and of their general ratios are obtained. Some particular cases and refinements are given. Finally, we obtain some important results involving inequalities of Bessel and Whittaker’s functions as applications.

  19. Purely Functional Structured Programming

    OpenAIRE

    Obua, Steven

    2010-01-01

    The idea of functional programming has played a big role in shaping today's landscape of mainstream programming languages. Another concept that dominates the current programming style is Dijkstra's structured programming. Both concepts have been successfully married, for example in the programming language Scala. This paper proposes how the same can be achieved for structured programming and PURELY functional programming via the notion of LINEAR SCOPE. One advantage of this proposal is that m...

  20. Exponential and Logarithmic Functions

    OpenAIRE

    Todorova, Tamara

    2010-01-01

    Exponential functions find applications in economics in relation to growth and economic dynamics. In these fields, quite often the choice variable is time and economists are trying to determine the best timing for certain economic activities to take place. An exponential function is one in which the independent variable appears in the exponent. Very often that exponent is time. In highly mathematical courses, it is a truism that students learn by doing, not by reading. Tamara Todorova’s Pr...

  1. Functionally graded materials

    CERN Document Server

    Mahamood, Rasheedat Modupe

    2017-01-01

    This book presents the concept of functionally graded materials as well as their use and different fabrication processes. The authors describe the use of additive manufacturing technology for the production of very complex parts directly from the three dimension computer aided design of the part by adding material layer after layer. A case study is also presented in the book on the experimental analysis of functionally graded material using laser metal deposition process.

  2. Confinement from correlation functions

    Science.gov (United States)

    Fister, Leonard; Pawlowski, Jan M.

    2013-08-01

    We compute the Polyakov loop potential in Yang-Mills theory from the fully dressed primitively divergent correlation functions only. This is done in a variety of functional approaches ranging from functional renormalization group equations over Dyson-Schwinger equations to two-particle irreducible functionals. We present a confinement criterion that links the infrared behavior of propagators and vertices to the Polyakov loop expectation value. The present work extends the works of [J. Braun , Phys. Lett. B 684, 262 (2010)PYLBAJ0370-2693; F. Marhauser and J. M. Pawlowski, arXiv:0812.1144; J. Braun , Eur. Phys. J. C 70, 689 (2010)EPCFFB1434-6044] to general functional methods and sharpens the confinement criterion presented there. The computations are based on the thermal correlation functions in the Landau gauge calculated in [L. Fister and J. M. Pawlowski, arXiv:1112.5440; L. Fister and J. M. Pawlowski, arXiv:1112.5429; L. Fister, Ph.D. thesis, Heidelberg University, 2012].

  3. Functional balance tests

    Directory of Open Access Journals (Sweden)

    Parvin Raji

    2012-12-01

    Full Text Available Background and Aim: All activities of daily living need to balance control in static and dynamic movements. In recent years, a numerous increase can be seen in the functional balance assessment tools. Functional balance tests emphasize on static and dynamic balance, balance in weight transfer, the equilibrium response to the imbalances, and functional mobility. These standardized and available tests assess performance and require minimal or no equipment and short time to run. Functional balance is prerequisite for the most static and dynamic activities in daily life and needs sufficient interaction between sensory and motor systems. According to the critical role of balance in everyday life, and wide application of functional balance tests in the diagnosis and assessment of patients, a review of the functional balance tests was performed.Methods: The Google Scholar, PubMed, Science Direct, Scopus, Magiran, Iran Medex, and IranDoc databases were reviewed and the reliable and valid tests which were mostly used by Iranian researchers were assessed.Conclusion: It seems that Berg balance scale (BBS have been studied by Iranian and foreign researches more than the other tests. This test has high reliability and validity in elderly and in the most neurological disorders.

  4. Handbook of functional equations functional inequalities

    CERN Document Server

    2014-01-01

    As Richard Bellman has so elegantly stated at the Second International Conference on General Inequalities (Oberwolfach, 1978), “There are three reasons for the study of inequalities: practical, theoretical, and aesthetic.” On the aesthetic aspects, he said, “As has been pointed out, beauty is in the eye of the beholder. However, it is generally agreed that certain pieces of music, art, or mathematics are beautiful. There is an elegance to inequalities that makes them very attractive.” The content of the Handbook focuses mainly on both old and recent developments on approximate homomorphisms, on a relation between the Hardy–Hilbert and the Gabriel inequality, generalized Hardy–Hilbert type inequalities on multiple weighted Orlicz spaces, half-discrete Hilbert-type inequalities, on affine mappings, on contractive operators, on multiplicative Ostrowski and trapezoid inequalities, Ostrowski type inequalities for the  Riemann–Stieltjes integral, means and related functional inequalities, Weighted G...

  5. Functional integration over geometries

    International Nuclear Information System (INIS)

    Mottola, E.

    1995-01-01

    The geometric construction of the functional integral over coset spaces M/G is reviewed. The inner product on the cotangent space of infinitesimal deformations of M defines an invariant distance and volume form, or functional integration measure on the full configuration space. Then, by a simple change of coordinates parameterizing the gauge fiber G, the functional measure on the coset space M/G is deduced. This change of integration variables leads to a Jacobian which is entirely equivalent to the Faddeev--Popov determinant of the more traditional gauge fixed approach in non-abelian gauge theory. If the general construction is applied to the case where G is the group of coordinate reparameterizations of spacetime, the continuum functional integral over geometries, i.e. metrics modulo coordinate reparameterizations may be defined. The invariant functional integration measure is used to derive the trace anomaly and effective action for the conformal part of the metric in two and four dimensional spacetime. In two dimensions this approach generates the Polyakov--Liouville action of closed bosonic non-critical string theory. In four dimensions the corresponding effective action leads to novel conclusions on the importance of quantum effects in gravity in the far infrared, and in particular, a dramatic modification of the classical Einstein theory at cosmological distance scales, signaled first by the quantum instability of classical de Sitter spacetime. Finite volume scaling relations for the functional integral of quantum gravity in two and four dimensions are derived, and comparison with the discretized dynamical triangulation approach to the integration over geometries are discussed. Outstanding unsolved problems in both the continuum definition and the simplicial approach to the functional integral over geometries are highlighted

  6. Predicting predatory impact of juvenile invasive lionfish (Pterois volitans) on a crustacean prey using functional response analysis: effects of temperature, habitat complexity and light regimes

    KAUST Repository

    South, Josie

    2017-07-01

    The ecological implications of biotic interactions, such as predator-prey relationships, are often context-dependent. Comparative functional responses analysis can be used under different abiotic contexts to improve understanding and prediction of the ecological impact of invasive species. Pterois volitans (Lionfish) [Linnaeus 1758] is an established invasive species in the Caribbean and Gulf of Mexico, with a more recent invasion into the Mediterranean. Lionfish are generalist predators that impact a wide range of commercial and non-commercial species. Functional response analysis was employed to quantify interaction strength between lionfish and a generic prey species, the shrimp (Paleomonetes varians) [Leach 1814], under the contexts of differing temperature, habitat complexity and light wavelength. Lionfish have prey population destabilising Type II functional responses under all contexts examined. Significantly more prey were consumed at 26 °C than at 22 °C. Habitat complexity did not significantly alter the functional response parameters. Significantly more prey were consumed under white light and blue light than under red light. Attack rate was significantly higher under white light than under blue or red light. Light wavelength did not significantly change handling times. The impacts on prey populations through feeding rates may increase with concomitant temperature increase. As attack rates are very high at low habitat complexity this may elucidate the cause of high impact upon degraded reef ecosystems with low-density prey populations, although there was little protection conferred through habitat complexity. Only red light (i.e. dark) afforded any reduction in predation pressure. Management initiatives should account for these environmental factors when planning mitigation and prevention strategies.

  7. The Functions of Sleep

    Directory of Open Access Journals (Sweden)

    Samson Z Assefa

    2015-08-01

    Full Text Available Sleep is a ubiquitous component of animal life including birds and mammals. The exact function of sleep has been one of the mysteries of biology. A considerable number of theories have been put forward to explain the reason(s for the necessity of sleep. To date, while a great deal is known about what happens when animals sleep, there is no definitive comprehensive explanation as to the reason that sleep is an inevitable part of animal functioning. It is well known that sleep is a homeostatically regulated body process, and that prolonged sleep deprivation is fatal in animals. In this paper, we present some of the theories as to the functions of sleep and provide a review of some hypotheses as to the overall physiologic function of sleep. To better understand the purpose for sleeping, we review the effects of sleep deprivation on physical, neurocognitive and psychic function. A better understanding of the purpose for sleeping will be a great advance in our understanding of the nature of the animal kingdom, including our own.

  8. Sperm function test

    Directory of Open Access Journals (Sweden)

    Pankaj Talwar

    2015-01-01

    Full Text Available With absolute normal semen analysis parameters it may not be necessary to shift to specialized tests early but in cases with borderline parameters or with history of fertilization failure in past it becomes necessary to do a battery of tests to evaluate different parameters of spermatozoa. Various sperm function tests are proposed and endorsed by different researchers in addition to the routine evaluation of fertility. These tests detect function of a certain part of spermatozoon and give insight on the events in fertilization of the oocyte. The sperms need to get nutrition from the seminal plasma in the form of fructose and citrate (this can be assessed by fructose qualitative and quantitative estimation, citrate estimation. They should be protected from the bad effects of pus cells and reactive oxygen species (ROS (leukocyte detection test, ROS estimation. Their number should be in sufficient in terms of (count, structure normal to be able to fertilize eggs (semen morphology. Sperms should have intact and functioning membrane to survive harsh environment of vagina and uterine fluids (vitality and hypo-osmotic swelling test, should have good mitochondrial function to be able to provide energy (mitochondrial activity index test. They should also have satisfactory acrosome function to be able to burrow a hole in zona pellucida (acrosome intactness test, zona penetration test. Finally, they should have properly packed DNA in the nucleus to be able to transfer the male genes (nuclear chromatic decondensation test to the oocyte during fertilization.

  9. Renal Function in Hypothyroidism

    International Nuclear Information System (INIS)

    Khalid, S.; Khalid, M; Elfaki, M.; Hassan, N.; Suliman, S.M.

    2007-01-01

    Background Hypothyroidism induces significant changes in the function of organ systems such as the heart, muscles and brain. Renal function is also influenced by thyroid status. Physiological effects include changes in water and electrolyte metabolism, notably hyponatremia, and reliable alterations of renal hemodynamics, including decrements in renal blood flow, renal plasma flow, glomerular filtration rate (GFR). Objective Renal function is profoundly influenced by thyroid status; the purpose of the present study was to determine the relationship between renal function and thyroid status of patients with hypothyroidism. Design and Patients In 5 patients with primary hypothyroidism and control group renal functions are measured by serum creatinine and glomerular filtration rate (GFR) using modified in diet renal disease (MDRD) formula. Result In hypothyroidism, mean serum creatinine increased and mean estimated GFR decreased, compared to the control group mean serum creatinine decreased and mean estimated GFR Increased. The hypothyroid patients showed elevated serum creatinine levels (> 1.1mg/dl) compared to control group (p value .000). In patients mean estimated GFR decreased, compared to mean estimated GFR increased in the control group (p value= .002).

  10. Renal Function in Hypothyroidism

    International Nuclear Information System (INIS)

    Khalid, A. S; Ahmed, M.I; Elfaki, H.M; Hassan, N.; Suliman, S. M.

    2006-12-01

    Background hypothyroidism induces significant changes in the function of organ systems such as the heart, muscles and brain. Renal function is also influenced by thyroid status. Physiological effects include changes in water and electrolyte metabolism, notably hyponatraemia, and reliable alterations of renal hemodynamics, including decrements in renal blood flow, renal plasma flow, glomerular filtration rate (GFR). Objective renal function is profoundly influenced by thyroid status, the purpose of the present study was to determine the relationship between renal function and thyroid status of patients with hypothyroidism. Design and patients in 5 patients with primary hypothyroidism and control group renal functions are measured by serum creatinine and glomerular filtration rate(GFR) using modified in diet renal disease (MDRD) formula. Result in hypothyroidism, mean serum creatinine increased and mean estimated GFR decreased, compared to the control group mean serum creatinine decreased and mean estimated GFR increased. The hypothyroid patients showed elevated serum creatinine levels(>1.1 mg/d1) compared to control group (p value= 000). In patients mean estimated GFR increased in the control group (p value=.002).Conclusion thus the kidney, in addition to the brain, heart and muscle, is an important target of the action of thyroid hormones.(Author)

  11. Histamine and astrocyte function.

    Science.gov (United States)

    Jurič, Damijana M; Kržan, Mojca; Lipnik-Stangelj, Metoda

    2016-09-01

    Astrocytes support the brain through numerous functional interactions in health and disease. The recent advances in our knowledge of astrocyte involvement in various neurological disorders raised up several questions about their role and functioning in the central nervous system. From the evidence discussed in this review, we show that histamine importantly influences the main astrocytic activities such as ion homeostasis, energy metabolism, neurotransmitter clearance, neurotrophic activity and immune response. These processes are mediated through at least three histamine receptor subtypes, H1, H2 and H3, expressed on the astrocyte surface. Thus, we recognize histamine as an important player in the modulation of astrocytic functions that deserves further considerations in exploring involvement of astrocytes in neurological disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Functional studies using NMR

    International Nuclear Information System (INIS)

    McCready, V.R.; Leach, M.O.; Sutton; Ell, P.

    1986-01-01

    The object of this book is to discuss and evaluate an area of Nuclear Magnetic Resonance which to date has been less emphasized than it might be, namely the use of NMR for functional studies. The book commences with a discussion of the areas in which the NMR techniques might be needed due to deficiencies in other techniques. The physics of NMR especially relating to functional measurement are then explained. Technical factors in producing functional images are discussed and the use of paramagnetic substances for carrying out flow studies are detailed. Particular attention is paid to specific studies in the various organs. The book ends with a survey of imaging in each organ and the relation of NMR images to other techniques such as ultrasound, nuclear medicine and X-rays

  13. Tendon functional extracellular matrix.

    Science.gov (United States)

    Screen, Hazel R C; Berk, David E; Kadler, Karl E; Ramirez, Francesco; Young, Marian F

    2015-06-01

    This article is one of a series, summarizing views expressed at the Orthopaedic Research Society New Frontiers in Tendon Research Conference. This particular article reviews the three workshops held under the "Functional Extracellular Matrix" stream. The workshops focused on the roles of the tendon extracellular matrix, such as performing the mechanical functions of tendon, creating the local cell environment, and providing cellular cues. Tendon is a complex network of matrix and cells, and its biological functions are influenced by widely varying extrinsic and intrinsic factors such as age, nutrition, exercise levels, and biomechanics. Consequently, tendon adapts dynamically during development, aging, and injury. The workshop discussions identified research directions associated with understanding cell-matrix interactions to be of prime importance for developing novel strategies to target tendon healing or repair. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  14. Protein Functionalized Nanodiamond Arrays

    Directory of Open Access Journals (Sweden)

    Liu YL

    2010-01-01

    Full Text Available Abstract Various nanoscale elements are currently being explored for bio-applications, such as in bio-images, bio-detection, and bio-sensors. Among them, nanodiamonds possess remarkable features such as low bio-cytotoxicity, good optical property in fluorescent and Raman spectra, and good photostability for bio-applications. In this work, we devise techniques to position functionalized nanodiamonds on self-assembled monolayer (SAMs arrays adsorbed on silicon and ITO substrates surface using electron beam lithography techniques. The nanodiamond arrays were functionalized with lysozyme to target a certain biomolecule or protein specifically. The optical properties of the nanodiamond-protein complex arrays were characterized by a high throughput confocal microscope. The synthesized nanodiamond-lysozyme complex arrays were found to still retain their functionality in interacting with E. coli.

  15. Ghrelin and Functional Dyspepsia

    Directory of Open Access Journals (Sweden)

    Takashi Akamizu

    2010-01-01

    Full Text Available The majority of patients with dyspepsia have no identifiable cause of their disease, leading to a diagnosis of functional dyspepsia (FD. While a number of different factors affect gut activity, components of the nervous and endocrine systems are essential for normal gut function. Communication between the brain and gut occurs via direct neural connections or endocrine signaling events. Ghrelin, a peptide produced by the stomach, affects gastric motility/emptying and secretion, suggesting it may play a pathophysiological role in FD. It is also possible that the functional abnormalities in FD may affect ghrelin production in the stomach. Plasma ghrelin levels are reported to be altered in FD, correlating with FD symptom score. Furthermore, some patients with FD suffer from anorexia with body-weight loss. As ghrelin increases gastric emptying and promotes feeding, ghrelin therapy may be a new approach to the treatment of FD.

  16. Spaces of continuous functions

    CERN Document Server

    Groenewegen, G L M

    2016-01-01

    The space C(X) of all continuous functions on a compact space X carries the structure of a normed vector space, an algebra and a lattice. On the one hand we study the relations between these structures and the topology of X, on the other hand we discuss a number of classical results according to which an algebra or a vector lattice can be represented as a C(X). Various applications of these theorems are given. Some attention is devoted to related theorems, e.g. the Stone Theorem for Boolean algebras and the Riesz Representation Theorem. The book is functional analytic in character. It does not presuppose much knowledge of functional analysis; it contains introductions into subjects such as the weak topology, vector lattices and (some) integration theory.

  17. Quantal density functional theory

    CERN Document Server

    Sahni, Viraht

    2016-01-01

    This book deals with quantal density functional theory (QDFT) which is a time-dependent local effective potential theory of the electronic structure of matter. The treated time-independent QDFT constitutes a special case. In the 2nd edition, the theory is extended to include the presence of external magnetostatic fields. The theory is a description of matter based on the ‘quantal Newtonian’ first and second laws which is in terms of “classical” fields that pervade all space, and their quantal sources. The fields, which are explicitly defined, are separately representative of electron correlations due to the Pauli exclusion principle, Coulomb repulsion, correlation-kinetic, correlation-current-density, and correlation-magnetic effects. The book further describes Schrödinger theory from the new physical perspective of fields and quantal sources. It also describes traditional Hohenberg-Kohn-Sham DFT, and explains via QDFT the physics underlying the various energy functionals and functional derivatives o...

  18. Platelet function in dogs

    DEFF Research Database (Denmark)

    Nielsen, Line A.; Zois, Nora Elisabeth; Pedersen, Henrik D.

    2007-01-01

    Background: Clinical studies investigating platelet function in dogs have had conflicting results that may be caused by normal physiologic variation in platelet response to agonists. Objectives: The objective of this study was to investigate platelet function in clinically healthy dogs of 4...... different breeds by whole-blood aggregometry and with a point-of-care platelet function analyzer (PFA-100), and to evaluate the effect of acetylsalicylic acid (ASA) administration on the results from both methods. Methods: Forty-five clinically healthy dogs (12 Cavalier King Charles Spaniels [CKCS], 12...... applied. However, the importance of these breed differences remains to be investigated. The PFA-100 method with Col + Epi as agonists, and ADP-induced platelet aggregation appear to be sensitive to ASA in dogs....

  19. The triad value function

    DEFF Research Database (Denmark)

    Vedel, Mette

    2016-01-01

    the triad value function. Next, the applicability and validity of the concept is examined in a case study of four closed vertical supply chain triads. Findings - The case study demonstrates that the triad value function facilitates the analysis and understanding of an apparent paradox; that distributors...... expands exponentially with the number of ties in the network. Moreover, it must be applied in the study of service triads and open vertical supply chain triads to further verify the practical adequacy of the concept. Practical implications - The triad value function cannot be used normatively...... or prescriptively. It is a descriptive tool which indirectly supports managerial decision-making through the analysis of how the structural context of a triad influences the value of relationships. Originality/value - The paper offers an additional aspect for the study of value in and of triads. It illustrates...

  20. Functional Programming Using F#

    DEFF Research Database (Denmark)

    Hansen, Michael Reichhardt; Rischel, Hans

    This comprehensive introduction to the principles of functional programming using F# shows how to apply basic theoretical concepts to produce succinct and elegant programs. It demonstrates the role of functional programming in a wide spectrum of applications including databases and systems....... Coverage also includes advanced features in the .NET library, the imperative features of F# and topics such as text processing, sequences, computation expressions and asynchronous computation. With a broad spectrum of examples and exercises, the book is perfect for courses in functional programming...... and for self-study. Enhancing its use as a text is an accompanying website with downloadable programs, lecture slides, a mini-projects and links to further F# sources....

  1. Functional brain imaging

    International Nuclear Information System (INIS)

    Frackowiak, R.S.J.

    1996-01-01

    Major advances in computing and mathematics, especially the back-projection algorithms introduced for reconstructing tomographic data obtained by non-invasive imaging, have led to new opportunities for the study of the structure, function and structure-function relationships of the human brain. Functional neuro-imaging methods fall, broadly, into two classes. Those methods that provide information about synaptic activity and those that provide information of a chemical or neurochemical nature. The former methods usually depend on some form of perfusion mapping because of the tight coupling between local glucose metabolism and blood flow in the brain at rest and at times of altered synaptic activity. The latter methods depend on identification of a chemical species of interest by using an appropriate radioligand, or by using the intrinsic magnetic properties of a compound. (author)

  2. Functional illiteracy in Slovenia

    Directory of Open Access Journals (Sweden)

    Ester Možina

    1999-12-01

    Full Text Available The author draws attention to the fact that, in determining functional illiteracy, there remain many terminological disagreements and diverse opinions regarding illiteracy. Furthermore, there are also different methods for measuring writing abilities, thus leading to disparate results. The introductory section presents the dilemmas relating to the term of functional illiteracy, while the second part is concerned with the various methods for measuring literacy. Thus, the author also critically assesses the research studies aimed at evaluating the scope of literacy amongst adults in Slovenia during the past decade. ln this paper, she has adopted a methodology which would not determine what is functional and what is not in our society, in order to avoid limiting the richness of individual writing praxis.

  3. Nucleon structure functions

    International Nuclear Information System (INIS)

    Virchaux, M.

    1992-11-01

    The present status of experimental measurements of the nucleon structure functions is reviewed. The results from nearly all deep inelastic experiments are in good mutual agreement. Principles of the analysis of these structure function data in the framework of QCD are described. The specific features of the perturbative QCD predictions are observed in the data. This provides quantitative tests of the validity of QCD as well as determinations of the various parton distributions in the nucleon and some of the most precise measurements of the strong coupling constant αs. The future of this field of experimental physics is sketched

  4. The Functions of Sleep

    OpenAIRE

    Samson Z Assefa; Montserrat Diaz-Abad; Emerson M Wickwire; Steven M Scharf

    2015-01-01

    Sleep is a ubiquitous component of animal life including birds and mammals. The exact function of sleep has been one of the mysteries of biology. A considerable number of theories have been put forward to explain the reason(s) for the necessity of sleep. To date, while a great deal is known about what happens when animals sleep, there is no definitive comprehensive explanation as to the reason that sleep is an inevitable part of animal functioning. It is well known that sleep is a homeostatic...

  5. Ego functions in epilepsy

    DEFF Research Database (Denmark)

    Sørensen, A S; Hansen, H; Høgenhaven, H

    1988-01-01

    Two groups of epilepsy patients (28 patients with temporal lobe epilepsy and 15 patients with primary generalized epilepsy) entered a study of personality traits related to epilepsy, based on a modification of Bellak's semistructured interview for assessment of ego strength. Two groups of subjects...... than 15 years when the disease began. The number of anticonvulsants administered did not influence the results. No difference on adaptive level of ego functioning was found between the group with primary generalized epilepsy and the group with temporal lobe epilepsy. Similarly, the temporal lobe...... epilepsy group with predominantly right-sided and left-sided EEG changes, respectively, showed similar adaptive levels of ego functioning....

  6. Complex function theory

    CERN Document Server

    Sarason, Donald

    2007-01-01

    Complex Function Theory is a concise and rigorous introduction to the theory of functions of a complex variable. Written in a classical style, it is in the spirit of the books by Ahlfors and by Saks and Zygmund. Being designed for a one-semester course, it is much shorter than many of the standard texts. Sarason covers the basic material through Cauchy's theorem and applications, plus the Riemann mapping theorem. It is suitable for either an introductory graduate course or an undergraduate course for students with adequate preparation. The first edition was published with the title Notes on Co

  7. GADRAS Detector Response Function.

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Dean J.; Harding, Lee; Thoreson, Gregory G; Horne, Steven M.

    2014-11-01

    The Gamma Detector Response and Analysis Software (GADRAS) applies a Detector Response Function (DRF) to compute the output of gamma-ray and neutron detectors when they are exposed to radiation sources. The DRF is fundamental to the ability to perform forward calculations (i.e., computation of the response of a detector to a known source), as well as the ability to analyze spectra to deduce the types and quantities of radioactive material to which the detectors are exposed. This document describes how gamma-ray spectra are computed and the significance of response function parameters that define characteristics of particular detectors.

  8. Chromatin Structure and Function

    CERN Document Server

    Wolffe, Alan P

    1999-01-01

    The Third Edition of Chromatin: Structure and Function brings the reader up-to-date with the remarkable progress in chromatin research over the past three years. It has been extensively rewritten to cover new material on chromatin remodeling, histone modification, nuclear compartmentalization, DNA methylation, and transcriptional co-activators and co-repressors. The book is written in a clear and concise fashion, with 60 new illustrations. Chromatin: Structure and Function provides the reader with a concise and coherent account of the nature, structure, and assembly of chromatin and its active

  9. Integral inequalities under beta function and preinvex type functions.

    Science.gov (United States)

    Ahmad, Izhar

    2016-01-01

    In the present paper, the notion of P-preinvex function is introduced and new integral inequalities for this kind of function along with beta function are establised. The work extends the results appeared in the literature.

  10. Graphical functions in parametric space

    Science.gov (United States)

    Golz, Marcel; Panzer, Erik; Schnetz, Oliver

    2017-06-01

    Graphical functions are positive functions on the punctured complex plane C{\\setminus }{0,1} which arise in quantum field theory. We generalize a parametric integral representation for graphical functions due to Lam, Lebrun and Nakanishi, which implies the real analyticity of graphical functions. Moreover, we prove a formula that relates graphical functions of planar dual graphs.

  11. Diet and Endothelial Function

    Directory of Open Access Journals (Sweden)

    ADA M CUEVAS

    2004-01-01

    Full Text Available Endothelial dysfunction is one of the earliest events in atherogenesis. A consequence of endothelial damage is a lower availability of nitric oxide (NO, the most potent endogenous vasodilator. NO inhibits platelet aggregation, smooth muscle cell proliferation and adhesion of monocytes to endothelial cells. Endothelial dysfunction is present in patients with cardiovascular disease and/or coronary risk factors, such as hypertension, dyslipidemia, diabetes, smoking or hyperhomocysteinemia. At present, soluble markers and high resolution ultrasound of the brachial artery, have provided simple tools for the study of endothelial function and the effects of several interventions. It has been demonstrated that dietary factors may induce significant changes on vascular reactivity. Nutrients, such as fish oil, antioxidants, L-arginine, folic acid and soy protein have shown an improvement in endothelial function that can mediate, at least partially, the cardioprotective effects of these substances. Attention has been focused on dietary patterns in populations with lower prevalence of cardiovascular disease. There is some evidence suggesting that Mediterranean diet characterized by high consumption of vegetables, fish, olive oil and moderate wine consumption may have a positive effect on endothelial function. These results give us evidence on the significant role of diet on endothelial function and its impact on the pathogenesis of atherosclerosis

  12. Automatic Functional Harmonic Analysis

    NARCIS (Netherlands)

    de Haas, W.B.|info:eu-repo/dai/nl/304841250; Magalhães, J.P.; Wiering, F.|info:eu-repo/dai/nl/141928034; Veltkamp, R.C.|info:eu-repo/dai/nl/084742984

    2013-01-01

    Music scholars have been studying tonal harmony intensively for centuries, yielding numerous theories and models. Unfortunately, a large number of these theories are formulated in a rather informal fashion and lack mathematical precision. In this article we present HarmTrace, a functional model of

  13. Functions of public relations

    Directory of Open Access Journals (Sweden)

    Baranov G. V.

    2016-09-01

    Full Text Available the article reveals the importance of communication with the public in the implementation of human rights and the ideals of mankind; characterized by the specificity of public relations in the information culture of belief; PR functions are explained on the criterion of optimization of activity of social interactions on the basis of cultural ideals.

  14. Linear Classification Functions.

    Science.gov (United States)

    Huberty, Carl J.; Smith, Jerry D.

    Linear classification functions (LCFs) arise in a predictive discriminant analysis for the purpose of classifying experimental units into criterion groups. The relative contribution of the response variables to classification accuracy may be based on LCF-variable correlations for each group. It is proved that, if the raw response measures are…

  15. Fuss Over Function

    DEFF Research Database (Denmark)

    Elsmore, Matthew James

    is an inherent work-in-progress, and hence labelled ‘Draft’. Moreover, this precise point, and my intended wider audience, also helps explain the inclusion of this essay on SSRN. Note: This draft essay has not been reviewed. Thus, any comments on its form and function are welcome, either via the IPKat post...

  16. Executive functions in synesthesia

    NARCIS (Netherlands)

    Rouw, R.; van Driel, J.; Knip, K.; Ridderinkhof, K.R.

    2013-01-01

    In grapheme-color synesthesia, a number or letter can evoke two different and possibly conflicting (real and synesthetic) color sensations at the same time. In this study, we investigate the relationship between synesthesia and executive control functions. First, no general skill differences were

  17. Functional ingredients from microalgae

    NARCIS (Netherlands)

    Buono, S.; Langellotti, A.L.; Martello, A.; Rinna, F.; Fogliano, V.

    2014-01-01

    A wide variety of natural sources are under investigation to evaluate their possible use for new functional ingredient formulation. Some records attested the traditional and ancient use of wild harvested microalgae as human food but their cultivation for different purposes started about 40 years

  18. Gluing Nekrasov Partition Functions

    Science.gov (United States)

    Qiu, Jian; Tizzano, Luigi; Winding, Jacob; Zabzine, Maxim

    2015-07-01

    In this paper we summarise the localisation calculation of 5D super Yang-Mills on simply connected toric Sasaki-Einstein (SE) manifolds. We show how various aspects of the computation, including the equivariant index, the asymptotic behaviour and the factorisation property are governed by the combinatorial data of the toric geometry. We prove that the perturbative partition function on a simply connected SE manifold corresponding to an n-gon toric diagram factorises to n copies of perturbative part (zero instanton sector) of the Nekrasov partition function. This leads us to conjecture a prescription for the computation of the complete partition function, by gluing n copies of the full Nekrasov partition functions. This work is a generalisation of some earlier computation carried out on Y p, q manifolds, whose moment map cone has a quadrangle base and our result is valid for manifolds whose moment map cones have pentagon base, hexagon base, etc. The algorithm we used for dealing with general cones may also be of independent interest.

  19. Objectification and Semiotic Function

    Science.gov (United States)

    Santi, George

    2011-01-01

    The objective of this paper is to study students' difficulties when they have to ascribe the same meaning to different representations of the same mathematical object. We address two theoretical tools that are at the core of Radford's cultural semiotic and Godino's onto-semiotic approaches: objectification and the semiotic function. The analysis…

  20. The Grindahl Hash Functions

    DEFF Research Database (Denmark)

    Knudsen, Lars Ramkilde; Rechberger, Christian; Thomsen, Søren Steffen

    2007-01-01

    In this paper we propose the Grindahl hash functions, which are based on components of the Rijndael algorithm. To make collision search sufficiently difficult, this design has the important feature that no low-weight characteristics form collisions, and at the same time it limits access to the st...

  1. Functional System Dynamics

    NARCIS (Netherlands)

    Ligterink, N.E.

    2007-01-01

    Functional system dynamics is the analysis, modelling, and simulation of continuous systems usually described by partial differential equations. From the infinite degrees of freedom of such systems only a finite number of relevant variables have to be chosen for a practical model description. The

  2. Nonlinear functional analysis

    CERN Document Server

    Deimling, Klaus

    1985-01-01

    topics. However, only a modest preliminary knowledge is needed. In the first chapter, where we introduce an important topological concept, the so-called topological degree for continuous maps from subsets ofRn into Rn, you need not know anything about functional analysis. Starting with Chapter 2, where infinite dimensions first appear, one should be familiar with the essential step of consider­ ing a sequence or a function of some sort as a point in the corresponding vector space of all such sequences or functions, whenever this abstraction is worthwhile. One should also work out the things which are proved in § 7 and accept certain basic principles of linear functional analysis quoted there for easier references, until they are applied in later chapters. In other words, even the 'completely linear' sections which we have included for your convenience serve only as a vehicle for progress in nonlinearity. Another point that makes the text introductory is the use of an essentially uniform mathematical languag...

  3. Functional Communication Training

    Science.gov (United States)

    Durand, V. Mark; Moskowitz, Lauren

    2015-01-01

    Thirty years ago, the first experimental demonstration was published showing that educators could improve significant challenging behavior in children with disabilities by replacing these behaviors with forms of communication that served the same purpose, a procedure called functional communication training (FCT). Since the publication of that…

  4. The function of ornaments

    DEFF Research Database (Denmark)

    Glaveanu, Vlad Petre

    2014-01-01

    of their manifold functions that integrates aesthetic and utilitarian, individual and social roles. Ornaments help us to identify and locate, tell or communicate, remind and organise our action, they guide our attention, express and individualise, can generate an experience, beautify as well as re...

  5. Automate functional testing

    Directory of Open Access Journals (Sweden)

    Ramesh Kalindri

    2014-06-01

    Full Text Available Currently, software engineers are increasingly turning to the option of automating functional tests, but not always have successful in this endeavor. Reasons range from low planning until over cost in the process. Some principles that can guide teams in automating these tests are described in this article.

  6. Density Functional Theory

    Indian Academy of Sciences (India)

    (1) The total energy of an electron system in an external potential is a unique functional of the total electron density; and. (2)The density that minimizes the energy is the ground-state density, and this minimum energy is the ground-state energy of the system.

  7. Functional consequences of hemispherectomy

    NARCIS (Netherlands)

    van Empelen, R; Jennekens-Schinkel, A; Buskens, E; Helders, PJM; van Nieuwenhuizen, O

    Using the International Classification of Functioning Disability and Health (ICF) (WHO, 2001), impairments, activities and social participation are reported in 12 children (mean age at surgery 5.9 years) who were investigated before and three times over a 2-year period after hemispherectomy.

  8. Laboratory Density Functionals

    OpenAIRE

    Giraud, B. G.

    2007-01-01

    We compare several definitions of the density of a self-bound system, such as a nucleus, in relation with its center-of-mass zero-point motion. A trivial deconvolution relates the internal density to the density defined in the laboratory frame. This result is useful for the practical definition of density functionals.

  9. Choice probability generating functions

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; McFadden, Daniel; Bierlaire, Michel

    2013-01-01

    This paper considers discrete choice, with choice probabilities coming from maximization of preferences from a random utility field perturbed by additive location shifters (ARUM). Any ARUM can be characterized by a choice-probability generating function (CPGF) whose gradient gives the choice...

  10. Choice Probability Generating Functions

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; McFadden, Daniel L; Bierlaire, Michel

    This paper considers discrete choice, with choice probabilities coming from maximization of preferences from a random utility field perturbed by additive location shifters (ARUM). Any ARUM can be characterized by a choice-probability generating function (CPGF) whose gradient gives the choice...

  11. Mapping functional connectivity

    Science.gov (United States)

    Peter Vogt; Joseph R. Ferrari; Todd R. Lookingbill; Robert H. Gardner; Kurt H. Riitters; Katarzyna Ostapowicz

    2009-01-01

    An objective and reliable assessment of wildlife movement is important in theoretical and applied ecology. The identification and mapping of landscape elements that may enhance functional connectivity is usually a subjective process based on visual interpretations of species movement patterns. New methods based on mathematical morphology provide a generic, flexible,...

  12. Empirical microeconomics action functionals

    Science.gov (United States)

    Baaquie, Belal E.; Du, Xin; Tanputraman, Winson

    2015-06-01

    A statistical generalization of microeconomics has been made in Baaquie (2013), where the market price of every traded commodity, at each instant of time, is considered to be an independent random variable. The dynamics of commodity market prices is modeled by an action functional-and the focus of this paper is to empirically determine the action functionals for different commodities. The correlation functions of the model are defined using a Feynman path integral. The model is calibrated using the unequal time correlation of the market commodity prices as well as their cubic and quartic moments using a perturbation expansion. The consistency of the perturbation expansion is verified by a numerical evaluation of the path integral. Nine commodities drawn from the energy, metal and grain sectors are studied and their market behavior is described by the model to an accuracy of over 90% using only six parameters. The paper empirically establishes the existence of the action functional for commodity prices that was postulated to exist in Baaquie (2013).

  13. Functional genomics of tomato

    Indian Academy of Sciences (India)

    2014-10-20

    Oct 20, 2014 ... very first challenge before scientists working on tomato functional biology is to exploit this high-quality reference sequence for tapping of the ... and exploitation of the genomic diversity present in Solanum genus, in general, and ..... associated with this tool retain its labour-intensive nature, ineffectiveness for ...

  14. Generalized elementary functions

    Czech Academy of Sciences Publication Activity Database

    Monteiro, Giselle Antunes; Slavík, A.

    2014-01-01

    Roč. 411, č. 2 (2014), s. 838-852 ISSN 0022-247X Institutional support: RVO:67985840 Keywords : elementary functions * Kurzweil-Stieltjes integral * generalized linear ordinary differential equations * time scale calculus Subject RIV: BA - General Mathematics Impact factor: 1.120, year: 2014 http://www.sciencedirect.com/science/article/pii/S0022247X13009141

  15. Functional Maximum Autocorrelation Factors

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Nielsen, Allan Aasbjerg

    2005-01-01

    \\verb+~+\\$\\backslash\\$cite{ramsay97} to functional maximum autocorrelation factors (MAF)\\verb+~+\\$\\backslash\\$cite{switzer85,larsen2001d}. We apply the method to biological shapes as well as reflectance spectra. {\\$\\backslash\\$bf Methods}. MAF seeks linear combination of the original variables that maximize autocorrelation between...

  16. Cobham recursive set functions

    Czech Academy of Sciences Publication Activity Database

    Beckmann, A.; Buss, S.; Friedman, S.-D.; Müller, M.; Thapen, Neil

    2016-01-01

    Roč. 167, č. 3 (2016), s. 335-369 ISSN 0168-0072 R&D Projects: GA ČR GBP202/12/G061 Institutional support: RVO:67985840 Keywords : set function * polynomial time * Cobham recursion Subject RIV: BA - General Mathematics Impact factor: 0.647, year: 2016 http://www.sciencedirect.com/science/article/pii/S0168007215001293

  17. density functional theory (DFT)

    Indian Academy of Sciences (India)

    Abstract. In the present investigation, interaction of ruthenium (Ru) atoms with fluorine (F) atoms was studied using the density functional theory utilizing B3LYP method. It was found that up to seven F atoms can bind to a single Ru atom which results in increase of electron affinities successively, reaching a peak value of ...

  18. Educating executive function.

    Science.gov (United States)

    Blair, Clancy

    2017-01-01

    Executive functions are thinking skills that assist with reasoning, planning, problem solving, and managing one's life. The brain areas that underlie these skills are interconnected with and influenced by activity in many different brain areas, some of which are associated with emotion and stress. One consequence of the stress-specific connections is that executive functions, which help us to organize our thinking, tend to be disrupted when stimulation is too high and we are stressed out, or too low when we are bored and lethargic. Given their central role in reasoning and also in managing stress and emotion, scientists have conducted studies, primarily with adults, to determine whether executive functions can be improved by training. By and large, results have shown that they can be, in part through computer-based videogame-like activities. Evidence of wider, more general benefits from such computer-based training, however, is mixed. Accordingly, scientists have reasoned that training will have wider benefits if it is implemented early, with very young children as the neural circuitry of executive functions is developing, and that it will be most effective if embedded in children's everyday activities. Evidence produced by this research, however, is also mixed. In sum, much remains to be learned about executive function training. Without question, however, continued research on this important topic will yield valuable information about cognitive development. WIREs Cogn Sci 2017, 8:e1403. doi: 10.1002/wcs.1403 For further resources related to this article, please visit the WIREs website. © 2016 Wiley Periodicals, Inc.

  19. Uniqueness property for quasiharmonic functions

    Directory of Open Access Journals (Sweden)

    Sevdiyor A. Imomkulov

    2014-10-01

    Full Text Available In this paper we consider a class of continuous functions, called quasiaharmonic functions, admitting best approximations by harmonic polynomials. In this class we prove a uniqueness theorem by analogy with the analytic functions.

  20. Quasi-extended asymptotic functions

    International Nuclear Information System (INIS)

    Todorov, T.D.

    1979-01-01

    The class F of ''quasi-extended asymptotic functions'' is introduced. It contains all extended asymptotic functions as well as some new asymptotic functions very similar to the Schwartz distributions. On the other hand, every two quasiextended asymptotic functions can be multiplied as opposed to the Schwartz distributions; in particular, the square delta 2 of an asymptotic function delta similar to Dirac's delta-function, is constructed as an example

  1. The Relationships between Weight Functions, Geometric Functions,and Compliance Functions in Linear Elastic Fracture Mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Rong [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    Linear elastic fracture mechanics is widely used in industry because it established simple and explicit relationships between the permissible loading conditions and the critical crack size that is allowed in a structure. Stress intensity factors are the above-mentioned functional expressions that relate load with crack size through geometric functions or weight functions. Compliance functions are to determine the crack/flaw size in a structure when optical inspection is inconvenient. As a result, geometric functions, weight functions and compliance functions have been intensively studied to determine the stress intensity factor expressions for different geometries. However, the relations between these functions have received less attention. This work is therefore to investigate the intrinsic relationships between these functions. Theoretical derivation was carried out and the results were verified on single-edge cracked plate under tension and bending. It is found out that the geometric function is essentially the non-dimensional weight function at the loading point. The compliance function is composed of two parts: a varying part due to crack extension and a constant part from the intact structure if no crack exists. The derivative of the compliance function at any location is the product of the geometric function and the weight function at the evaluation point. Inversely, the compliance function can be acquired by the integration of the product of the geometric function and the weight function with respect to the crack size. The integral constant is just the unchanging compliance from the intact structure. Consequently, a special application of the relations is to obtain the compliance functions along a crack once the geometric function and weight functions are known. Any of the three special functions can be derived once the other two functions are known. These relations may greatly simplify the numerical process in obtaining either geometric functions, weight

  2. Coevolutionary modeling of protein sequences: Predicting structure, function, and mutational landscapes

    Science.gov (United States)

    Weigt, Martin

    Over the last years, biological research has been revolutionized by experimental high-throughput techniques, in particular by next-generation sequencing technology. Unprecedented amounts of data are accumulating, and there is a growing request for computational methods unveiling the information hidden in raw data, thereby increasing our understanding of complex biological systems. Statistical-physics models based on the maximum-entropy principle have, in the last few years, played an important role in this context. To give a specific example, proteins and many non-coding RNA show a remarkable degree of structural and functional conservation in the course of evolution, despite a large variability in amino acid sequences. We have developed a statistical-mechanics inspired inference approach - called Direct-Coupling Analysis - to link this sequence variability (easy to observe in sequence alignments, which are available in public sequence databases) to bio-molecular structure and function. In my presentation I will show, how this methodology can be used (i) to infer contacts between residues and thus to guide tertiary and quaternary protein structure prediction and RNA structure prediction, (ii) to discriminate interacting from non-interacting protein families, and thus to infer conserved protein-protein interaction networks, and (iii) to reconstruct mutational landscapes and thus to predict the phenotypic effect of mutations. References [1] M. Figliuzzi, H. Jacquier, A. Schug, O. Tenaillon and M. Weigt ''Coevolutionary landscape inference and the context-dependence of mutations in beta-lactamase TEM-1'', Mol. Biol. Evol. (2015), doi: 10.1093/molbev/msv211 [2] E. De Leonardis, B. Lutz, S. Ratz, S. Cocco, R. Monasson, A. Schug, M. Weigt ''Direct-Coupling Analysis of nucleotide coevolution facilitates RNA secondary and tertiary structure prediction'', Nucleic Acids Research (2015), doi: 10.1093/nar/gkv932 [3] F. Morcos, A. Pagnani, B. Lunt, A. Bertolino, D. Marks, C

  3. Density functional theory

    International Nuclear Information System (INIS)

    Das, M.P.

    1984-07-01

    The state of the art of the density functional formalism (DFT) is reviewed. The theory is quantum statistical in nature; its simplest version is the well-known Thomas-Fermi theory. The DFT is a powerful formalism in which one can treat the effect of interactions in inhomogeneous systems. After some introductory material, the DFT is outlined from the two basic theorems, and various generalizations of the theorems appropriate to several physical situations are pointed out. Next, various approximations to the density functionals are presented and some practical schemes, discussed; the approximations include an electron gas of almost constant density and an electron gas of slowly varying density. Then applications of DFT in various diverse areas of physics (atomic systems, plasmas, liquids, nuclear matter) are mentioned, and its strengths and weaknesses are pointed out. In conclusion, more recent developments of DFT are indicated

  4. Differentiation of real functions

    CERN Document Server

    Bruckner, Andrew

    1994-01-01

    Topics related to the differentiation of real functions have received considerable attention during the last few decades. This book provides an efficient account of the present state of the subject. Bruckner addresses in detail the problems that arise when dealing with the class \\Delta ' of derivatives, a class that is difficult to handle for a number of reasons. Several generalized forms of differentiation have assumed importance in the solution of various problems. Some generalized derivatives are excellent substitutes for the ordinary derivative when the latter is not known to exist; others are not. Bruckner studies generalized derivatives and indicates "geometric" conditions that determine whether or not a generalized derivative will be a good substitute for the ordinary derivative. There are a number of classes of functions closely linked to differentiation theory, and these are examined in some detail. The book unifies many important results from the literature as well as some results not previously pub...

  5. Process for functionalizing alkanes

    Science.gov (United States)

    Bergman, R.G.; Janowicz, A.H.; Periana-Pillai, R.A.

    1984-06-12

    Process for functionalizing saturated hydrocarbons selectively in the terminal position comprises: (a) reacting said saturated hydrocarbons with a metal complex CpRhPMe/sub 3/H/sub 2/ in the presence of ultraviolet radiation at -60/sup 0/ to -17/sup 0/C to form a hydridoalkyl complex CpRhPMe/sub 3/RH; (b) reacting said hydridoalkyl complex with a haloform CHX/sub 3/ at -60/sup 0/ to -17/sup 0/C to form the corresponding haloalkyl complex of step (a) CpRhPMe/sub 3/RX; and (c) reacting said haloalkyl complex with halogen -60 to 25/sup 0/C to form a functional haloalkyl compound.

  6. Nuclear Parton Distribution Functions

    Energy Technology Data Exchange (ETDEWEB)

    I. Schienbein, J.Y. Yu, C. Keppel, J.G. Morfin, F. Olness, J.F. Owens

    2009-06-01

    We study nuclear effects of charged current deep inelastic neutrino-iron scattering in the framework of a {chi}{sup 2} analysis of parton distribution functions (PDFs). We extract a set of iron PDFs which are used to compute x{sub Bj}-dependent and Q{sup 2}-dependent nuclear correction factors for iron structure functions which are required in global analyses of free nucleon PDFs. We compare our results with nuclear correction factors from neutrino-nucleus scattering models and correction factors for charged-lepton--iron scattering. We find that, except for very high x{sub Bj}, our correction factors differ in both shape and magnitude from the correction factors of the models and charged-lepton scattering.

  7. Ramanujan's theta functions

    CERN Document Server

    Cooper, Shaun

    2017-01-01

    Theta functions were studied extensively by Ramanujan. This book provides a systematic development of Ramanujan’s results and extends them to a general theory. The author’s treatment of the subject is comprehensive, providing a detailed study of theta functions and modular forms for levels up to 12. Aimed at advanced undergraduates, graduate students, and researchers, the organization, user-friendly presentation, and rich source of examples, lends this book to serve as a useful reference, a pedagogical tool, and a stimulus for further research. Topics, especially those discussed in the second half of the book, have been the subject of much recent research; many of which are appearing in book form for the first time. Further results are summarized in the numerous exercises at the end of each chapter.

  8. Functional foods in Europe

    DEFF Research Database (Denmark)

    Bech-Larsen, Tino; Scholderer, Joachim

    2007-01-01

    reading of the main principles of the harmonized regulation COM/2003/0424, this situation is about to change. This article reviews the regulatory aspects, the results of consumer research and the marketing strategies regarding the use of health claims for functional foods in Europe, and it comments......The fact that the European markets for functional foods generally are less developed, compared to the US and the Japanese markets, has often been attributed to a restrictive and inconsistent health claim legislation in and between the European countries. With the European Parliament's second...... on the lack of correspondence between the new regulation and the marketing experiences and research as regard consumer reactions to health claims....

  9. Functionalization of Carbon Nanotubes

    Science.gov (United States)

    Khare, Bishun N. (Inventor); Meyyappan, Meyya (Inventor)

    2009-01-01

    Method and system for functionalizing a collection of carbon nanotubes (CNTs). A selected precursor gas (e.g., H2 or F2 or CnHm) is irradiated to provide a cold plasma of selected target species particles, such as atomic H or F, in a first chamber. The target species particles are d irected toward an array of CNTs located in a second chamber while suppressing transport of ultraviolet radiation to the second chamber. A CNT array is functionalized with the target species particles, at or below room temperature, to a point of saturation, in an exposure time interval no longer than about 30 sec. *Discrimination against non-target species is provided by (i) use of a target species having a lifetime that is much greater than a lifetime of a non-target species and/or (2) use of an applied magnetic field to discriminate between charged particle trajectories for target species and for non-target species.

  10. Functional studies using NMR

    International Nuclear Information System (INIS)

    McCready, V.R.; Leach, M.; Ell, P.J.

    1987-01-01

    This volume is based on a series of lectures delivered at a one-day teaching symposium on functional and metabolic aspects of NMR measurements held at the Middlesex Hospital Medical School on 1st September 1985 as a part of the European Nuclear Medicine Society Congress. Currently the major emphasis in medical NMR in vivo is on its potential to image and display abnormalities in conventional radiological images, providing increased contrast between normal and abnormal tissue, improved definition of vasculature, and possibly an increased potential for differential diagnosis. Although these areas are undeniably of major importance, it is probable that NMR will continue to complement conventional measurement methods. The major potential benefits to be derived from in vivo NMR measurements are likely to arise from its use as an instrument for functional and metabolic studies in both clinical research and in the everyday management of patients. It is to this area that this volume is directed

  11. Sexual function and obesity

    DEFF Research Database (Denmark)

    Larsen, S H; Wagner, G; Heitmann, B L

    2007-01-01

    function and dysfunction. COMMENTS: Four prospective and seven cross-sectional studies were found describing association between obesity and erectile dysfunction (ED). One cross-sectional study was found describing obesity and female sexual dysfunction (FSD). The prospective studies on ED all demonstrated......OBJECTIVE: To review the literature on the relationship between obesity and sexual function. METHOD: A search in the medical literature from 1966 and onwards was carried out through Medline and Embase for publications on obesity, in combination with Medical Subject Heading words related to sexual...... a direct association and so did five of the seven cross-sectional studies. The single FSD study did not find any relationship. Eight intervention studies on weight loss and sexual difficulties were identified. All included few individuals and results were mixed even if most indicated an increase of sexual...

  12. Ego functions in epilepsy

    DEFF Research Database (Denmark)

    Sørensen, A S; Hansen, H; Høgenhaven, H

    1988-01-01

    Two groups of epilepsy patients (28 patients with temporal lobe epilepsy and 15 patients with primary generalized epilepsy) entered a study of personality traits related to epilepsy, based on a modification of Bellak's semistructured interview for assessment of ego strength. Two groups of subjects...... served as controls: 15 patients with a non-neurological but relapsing disorder, psoriasis, and 15 healthy volunteers. Compared with the group of healthy volunteers, a decreased adaptive level of ego functioning was found in the epilepsy groups, regardless of seizure types and EEG findings, and...... than 15 years when the disease began. The number of anticonvulsants administered did not influence the results. No difference on adaptive level of ego functioning was found between the group with primary generalized epilepsy and the group with temporal lobe epilepsy. Similarly, the temporal lobe...

  13. The Function of Sleep

    Directory of Open Access Journals (Sweden)

    Daniel A. Barone

    2015-06-01

    Full Text Available The importance of sleep can be ascertained by noting the effects of its loss, which tends to be chronic and partial, on cognition, mood, alertness, and overall health. Many theories have been put forth to explain the function of sleep in humans, including proposals based on energy conservation, ecological adaptations, neurocognitive function, neural plasticity, nervous system and physical health, and performance. Most account for only a portion of sleep behavior and few are based on strong experimental support. In this review, we present theories proposing why sleep is necessary and supporting data demonstrating the effects of inadequate sleep, with the intention of gleaning further information as to its necessity, which remains one of the most perplexing mysteries in biology.

  14. Pancreatic exocrine function testing

    International Nuclear Information System (INIS)

    Goff, J.S.

    1981-01-01

    It is important to understand which pancreatic function tests are available and how to interpret them when evaluating patients with malabsorption. Available direct tests are the secretin stimulation test, the Lundh test meal, and measurement of serum or fecal enzymes. Indirect tests assess pancreatic exocrine function by measuring the effect of pancreatic secretion on various nutrients. These include triglycerides labeled with carbon 14, cobalamin labeled with cobalt 57 and cobalt 58, and para-aminobenzoic acid bound to a dipeptide. Of all these tests the secretin stimulation test is the most accurate and reliable if done by experienced personnel. However, the indirect tests are simpler to do and appear to be comparable to the secretin test at detecting pancreatic exocrine insufficiency. These indirect tests are becoming clinically available and clinicians should familiarize themselves with the strengths and weaknesses of each

  15. Towards the Innovation Function

    Directory of Open Access Journals (Sweden)

    Paulo Antônio Zawislak

    2008-12-01

    Full Text Available This paper explores the main elements that influence innovation and the relationships among them. It is pointed out that innovation results from an entrepreneurial action inside an established institutional context, sustained by resources, abilities and competences and with the support of the necessary financial capital. Therefore, it is proposed that innovation is a function (just as the microeconomic production function composed of entrepreneurship, institutions, capabilities and capital. Each one of these elements is explored individually, so that later the relationships among them can be analyzed. It is still suggested that the size of the firm is a moderator in the relationship between these elements and innovation. The study’s contribution it is the development of a conceptual model.

  16. Vestibular function testing.

    LENUS (Irish Health Repository)

    Lang, E E

    2010-06-01

    Vestibular symptoms of vertigo, dizziness and dysequilibrium are common complaints which can be disabling both physically and psychologically. Routine examination of the ear nose and throat and neurological system are often normal in these patients. An accurate history and thorough clinical examination can provide a diagnosis in the majority of patients. However, in a subgroup of patients, vestibular function testing may be invaluable in arriving at a correct diagnosis and ultimately in the optimal treatment of these patients.

  17. Applied functional analysis

    CERN Document Server

    Oden, J Tinsley

    2010-01-01

    The textbook is designed to drive a crash course for beginning graduate students majoring in something besides mathematics, introducing mathematical foundations that lead to classical results in functional analysis. More specifically, Oden and Demkowicz want to prepare students to learn the variational theory of partial differential equations, distributions, and Sobolev spaces and numerical analysis with an emphasis on finite element methods. The 1996 first edition has been used in a rather intensive two-semester course. -Book News, June 2010

  18. Generalised twisted partition functions

    CERN Document Server

    Petkova, V B

    2001-01-01

    We consider the set of partition functions that result from the insertion of twist operators compatible with conformal invariance in a given 2D Conformal Field Theory (CFT). A consistency equation, which gives a classification of twists, is written and solved in particular cases. This generalises old results on twisted torus boundary conditions, gives a physical interpretation of Ocneanu's algebraic construction, and might offer a new route to the study of properties of CFT.

  19. Cobham recursive set functions

    Czech Academy of Sciences Publication Activity Database

    Beckmann, A.; Buss, S.; Friedman, S.-D.; Müller, M.; Thapen, Neil

    2016-01-01

    Roč. 167, č. 3 (2016), s. 335-369 ISSN 0168-0072 R&D Projects: GA ČR GBP202/12/G061 Institutional support: RVO:67985840 Keywords : set function * polynomial time * Cobham recursion Subject RIV: BA - General Mathematics Impact factor: 0.647, year: 2016 http://www. science direct.com/ science /article/pii/S0168007215001293

  20. Function integrated track system

    OpenAIRE

    Hohnecker, Eberhard

    2010-01-01

    The paper discusses a function integrated track system that focuses on the reduction of acoustic emissions from railway lines. It is shown that the combination of an embedded rail system (ERS), a sound absorbing track surface, and an integrated mini sound barrier has significant acoustic advantages compared to a standard ballast superstructure. The acoustic advantages of an embedded rail system are particularly pronounced in the case of railway bridges. Finally, it is shown that a...

  1. Controlling Lipschitz functions

    OpenAIRE

    Kupavskii, Andrey; Pach, Janos; Tardos, Gabor

    2017-01-01

    Given any positive integers $m$ and $d$, we say the a sequence of points $(x_i)_{i\\in I}$ in $\\mathbb R^m$ is {\\em Lipschitz-$d$-controlling} if one can select suitable values $y_i\\; (i\\in I)$ such that for every Lipschitz function $f:\\mathbb R^m\\rightarrow \\mathbb R^d$ there exists $i$ with $|f(x_i)-y_i|

  2. Migrativity of aggregation functions

    Czech Academy of Sciences Publication Activity Database

    Bustince, H.; Montero, J.; Mesiar, Radko

    2009-01-01

    Roč. 160, č. 6 (2009), s. 766-777 ISSN 0165-0114 R&D Projects: GA ČR GA402/08/0618 Institutional research plan: CEZ:AV0Z10750506 Keywords : Aggregation functions * Associativity * Bisymmetry * Migrativity * Nullnorms * t-Norms * Uninorms Subject RIV: BA - General Mathematics Impact factor: 2.138, year: 2009 http://library.utia.cas.cz/separaty/2009/E/masiar-migrativityofaggregationfunctions.pdf

  3. Peroxisome Biogenesis and Function

    OpenAIRE

    Kaur, Navneet; Reumann, Sigrun; Hu, Jianping

    2009-01-01

    Peroxisomes are small and single membrane-delimited organelles that execute numerous metabolic reactions and have pivotal roles in plant growth and development. In recent years, forward and reverse genetic studies along with biochemical and cell biological analyses in Arabidopsis have enabled researchers to identify many peroxisome proteins and elucidate their functions. This review focuses on the advances in our understanding of peroxisome biogenesis and metabolism, and further explores the ...

  4. Functional organic thin films

    OpenAIRE

    Scharnberg, Michael

    2007-01-01

    Organic thin films are used in many technological and engineering applications nowadays. They find use as coatings, sensors, detectors, as matrix materials in nanocomposites, as self-assembled monolayers for surface functionalization, as low-k dielectrics in integrated circuits and in advanced organic electronic applications like organic light emitting diodes, organic field effect transistors and organic photovoltaics (esp. organic solar cells) and many other applications. OLED displays are n...

  5. Cybernetic functioning in stuttering

    Directory of Open Access Journals (Sweden)

    Ursula Zsilavecz

    1981-11-01

    Full Text Available The aim of this study was to evaluate different kinds of masking noise and DAF, in order to identify the condition which would elicit the highest incidence of fluency in a group of stutterers. The study demonstrates that masking noise and DAF can be effectively applied as an aid in a therapy programme, viz. noise can effectively be put to use so as to encourage and reinforce somesthesia. Stuttering is viewed as defective functioning in the cybernetic system.

  6. Engineering functional bladder tissues.

    Science.gov (United States)

    Horst, Maya; Madduri, Srinivas; Gobet, Rita; Sulser, Tullio; Milleret, Vinzent; Hall, Heike; Atala, Anthony; Eberli, Daniel

    2013-07-01

    End stage bladder disease can seriously affect patient quality of life and often requires surgical reconstruction with bowel tissue, which is associated with numerous complications. Bioengineering of functional bladder tissue using tissue-engineering techniques could provide new functional tissues for reconstruction. In this review, we discuss the current state of this field and address different approaches to enable physiologic voiding in engineered bladder tissues in the near future. In a collaborative effort, we gathered researchers from four institutions to discuss the current state of functional bladder engineering. A MEDLINE® and PubMed® search was conducted for articles related to tissue engineering of the bladder, with special focus on the cells and biomaterials employed as well as the microenvironment, vascularisation and innervation strategies used. Over the last decade, advances in tissue engineering technology have laid the groundwork for the development of a biological substitute for bladder tissue that can support storage of urine and restore physiologic voiding. Although many researchers have been able to demonstrate the formation of engineered tissue with a structure similar to that of native bladder tissue, restoration of physiologic voiding using these constructs has never been demonstrated. The main issues hindering the development of larger contractile tissues that allow physiologic voiding include the development of correct muscle alignment, proper innervation and vascularization. Tissue engineering of a construct that will support the contractile properties that allow physiologic voiding is a complex process. The combination of smart scaffolds with controlled topography, the ability to deliver multiple trophic factors and an optimal cell source will allow for the engineering of functional bladder tissues in the near future. Copyright © 2012 John Wiley & Sons, Ltd.

  7. Hexagonalization of correlation functions

    International Nuclear Information System (INIS)

    Fleury, Thiago; Komatsu, Shota

    2017-01-01

    We propose a nonperturbative framework to study general correlation functions of single-trace operators in N=4 supersymmetric Yang-Mills theory at large N. The basic strategy is to decompose them into fundamental building blocks called the hexagon form factors, which were introduced earlier to study structure constants using integrability. The decomposition is akin to a triangulation of a Riemann surface, and we thus call it hexagonalization. We propose a set of rules to glue the hexagons together based on symmetry, which naturally incorporate the dependence on the conformal and the R-symmetry cross ratios. Our method is conceptually different from the conventional operator product expansion and automatically takes into account multi-trace operators exchanged in OPE channels. To illustrate the idea in simple set-ups, we compute four-point functions of BPS operators of arbitrary lengths and correlation functions of one Konishi operator and three short BPS operators, all at one loop. In all cases, the results are in perfect agreement with the perturbative data. We also suggest that our method can be a useful tool to study conformal integrals, and show it explicitly for the case of ladder integrals.

  8. Hexagonalization of correlation functions

    Energy Technology Data Exchange (ETDEWEB)

    Fleury, Thiago [Instituto de Física Teórica, UNESP - University Estadual Paulista,ICTP South American Institute for Fundamental Research,Rua Dr. Bento Teobaldo Ferraz 271, 01140-070, São Paulo, SP (Brazil); Komatsu, Shota [Perimeter Institute for Theoretical Physics,31 Caroline St N Waterloo, Ontario N2L 2Y5 (Canada)

    2017-01-30

    We propose a nonperturbative framework to study general correlation functions of single-trace operators in N=4 supersymmetric Yang-Mills theory at large N. The basic strategy is to decompose them into fundamental building blocks called the hexagon form factors, which were introduced earlier to study structure constants using integrability. The decomposition is akin to a triangulation of a Riemann surface, and we thus call it hexagonalization. We propose a set of rules to glue the hexagons together based on symmetry, which naturally incorporate the dependence on the conformal and the R-symmetry cross ratios. Our method is conceptually different from the conventional operator product expansion and automatically takes into account multi-trace operators exchanged in OPE channels. To illustrate the idea in simple set-ups, we compute four-point functions of BPS operators of arbitrary lengths and correlation functions of one Konishi operator and three short BPS operators, all at one loop. In all cases, the results are in perfect agreement with the perturbative data. We also suggest that our method can be a useful tool to study conformal integrals, and show it explicitly for the case of ladder integrals.

  9. [Endocrine function in obesity].

    Science.gov (United States)

    Álvarez-Castro, Paula; Sangiao-Alvarellos, Susana; Brandón-Sandá, Iria; Cordido, Fernando

    2011-10-01

    Obesity is associated to significant disturbances in endocrine function. Hyper insulinemia and insulin resistance are the best known changes in obesity, but their mechanisms and clinical significance are not clearly established. Adipose tissue is considered to be a hormone-secreting endocrine organ; and increased leptin secretion from the adipocyte, a satiety signal, is a well-established endocrine change in obesity. In obesity there is a decreased GH secretion. Impairment of somatotropic function in obesity is functional and may be reversed in certain circumstances. The pathophysiological mechanism responsible for low GH secretion in obesity is probably multifactorial. There are many data suggesting that a chronic state of somatostatin hypersecretion results in inhibition of GH release. Increased FFA levels, as well as a deficient ghrelin secretion, probably contribute to the impaired GH secretion. In women, abdominal obesity is associated to hyperandrogenism and low sex hormone-binding globulin levels. Obese men, particularly those with morbid obesity, have decreased testosterone and gonadotropin levels. Obesity is associated to an increased cortisol production rate, which is compensated for by a higher cortisol clearance, resulting in plasma free cortisol levels that do not change when body weight increases. Ghrelin is the only known circulating orexigenic factor, and has been found to be decreased in obese people. In obesity there is also a trend to increased TSH and free T3 levels. Copyright © 2011 SEEN. Published by Elsevier Espana. All rights reserved.

  10. Carbasugars: Synthesis and Functions

    Science.gov (United States)

    Kobayashi, Yoshiyuki

    It is well recognized that glycosidase inhibitors are not only tools to elucidate the mechanism of a living system manipulated by glycoconjugates but also potential clinical drugs and insecticides by inducing the failure of glycoconjugates to perform their function. In this chapter, the syntheses and functions of natural glycosidase inhibitors (cyclophelitol , allosamidine , and trehazoilin ), which possess highly oxygenated and functionalized cyclohexanes or cyclopentanes in their structures and are defined as carbasugars , and the structure and activity relationships (SAR) of their derivatives are described. Also, recently much attention has been focused on neuraminidase inhibitors as anti-influenza drugs since relenza , which was derived from sialic acid, and also, tamiflu , which is the artificial carbasugar designed as a transition state analogue in the hydrolysis pathway of substrates by neuraminidase, were launched in the market. Herein, the medicinal chemistry efforts to discover tamiflu and some efficient syntheses applicable to process chemistry are described. Finally, useful synthetic methodologies for carbasugar formation from sugars are also introduced in this chapter.

  11. Lutein and Brain Function

    Directory of Open Access Journals (Sweden)

    John W. Erdman

    2015-10-01

    Full Text Available Lutein is one of the most prevalent carotenoids in nature and in the human diet. Together with zeaxanthin, it is highly concentrated as macular pigment in the foveal retina of primates, attenuating blue light exposure, providing protection from photo-oxidation and enhancing visual performance. Recently, interest in lutein has expanded beyond the retina to its possible contributions to brain development and function. Only primates accumulate lutein within the brain, but little is known about its distribution or physiological role. Our team has begun to utilize the rhesus macaque (Macaca mulatta model to study the uptake and bio-localization of lutein in the brain. Our overall goal has been to assess the association of lutein localization with brain function. In this review, we will first cover the evolution of the non-human primate model for lutein and brain studies, discuss prior association studies of lutein with retina and brain function, and review approaches that can be used to localize brain lutein. We also describe our approach to the biosynthesis of 13C-lutein, which will allow investigation of lutein flux, localization, metabolism and pharmacokinetics. Lastly, we describe potential future research opportunities.

  12. Multilevel functional clustering analysis.

    Science.gov (United States)

    Serban, Nicoleta; Jiang, Huijing

    2012-09-01

    In this article, we investigate clustering methods for multilevel functional data, which consist of repeated random functions observed for a large number of units (e.g., genes) at multiple subunits (e.g., bacteria types). To describe the within- and between variability induced by the hierarchical structure in the data, we take a multilevel functional principal component analysis (MFPCA) approach. We develop and compare a hard clustering method applied to the scores derived from the MFPCA and a soft clustering method using an MFPCA decomposition. In a simulation study, we assess the estimation accuracy of the clustering membership and the cluster patterns under a series of settings: small versus moderate number of time points; various noise levels; and varying number of subunits per unit. We demonstrate the applicability of the clustering analysis to a real data set consisting of expression profiles from genes activated by immunity system cells. Prevalent response patterns are identified by clustering the expression profiles using our multilevel clustering analysis. © 2012, The International Biometric Society.

  13. Functions of multivector variables.

    Directory of Open Access Journals (Sweden)

    James M Chappell

    Full Text Available As is well known, the common elementary functions defined over the real numbers can be generalized to act not only over the complex number field but also over the skew (non-commuting field of the quaternions. In this paper, we detail a number of elementary functions extended to act over the skew field of Clifford multivectors, in both two and three dimensions. Complex numbers, quaternions and Cartesian vectors can be described by the various components within a Clifford multivector and from our results we are able to demonstrate new inter-relationships between these algebraic systems. One key relationship that we discover is that a complex number raised to a vector power produces a quaternion thus combining these systems within a single equation. We also find a single formula that produces the square root, amplitude and inverse of a multivector over one, two and three dimensions. Finally, comparing the functions over different dimension we observe that Cl(R(3 provides a particularly versatile algebraic framework.

  14. [Functional hypothalamic amenorrhea].

    Science.gov (United States)

    Stárka, Luboslav; Dušková, Michaela

    2015-10-01

    Functional hypothalamic amenorrhea (FHA) besides pregnancy and syndrome of polycystic ovary is one of the most common causes of secondary amenorrhea. FHA results from the aberrations in pulsatile gonadotropin-releasing hormone (GnRH) secretion, which in turn causes impairment of the gonadotropins (follicle-stimulating hormone and luteinizing hormone). FHA is a form of the defence of organism in situations where life functions are more important than reproductive function. FHA is reversible; it can be normalized after ceasing the stress situation. There are three types of FHA: weight loss related, stress-related, and exercise-related amenorrhea. The final consequences are complex hormonal changes manifested by profound hypoestrogenism. Additionally, these patients present mild hypercortisolemia, low serum insulin levels, low insulin-like growth factor 1 (IGF-1) and low total triiodothyronine. Women health in this disorder is disturbed in several aspects including the skeletal system, cardiovascular system, and mental problems. Patients manifest a decrease in bone mass density, which is related to an increase in fracture risk. Therefore, osteopenia and osteoporosis are the main long-term complications of FHA. Cardiovascular complications include endothelial dysfunction and abnormal changes in the lipid profile. FHA patients present significantly higher depression and anxiety and also sexual problems compared to healthy subjects.

  15. Orexins and gastrointestinal functions.

    Science.gov (United States)

    Baccari, M C

    2010-03-01

    Orexin A (OXA) and orexin B (OXB) are recently discovered neuropeptides that appear to play a role in various distinct functions such as arousal and the sleep-wake cycle as well as on appetite and regulation of feeding and energy homeostasis. Orexins were first described as neuropeptides expressed by a specific population of neurons in the lateral hypothalamic area, a region classically implicated in feeding behaviour. Orexin neurons project to numerous brain regions, where orexin receptors have been shown to be widely distributed: both OXA and OXB act through two subtypes of receptors (OX1R and OX2R) that belong to the G protein-coupled superfamily of receptors. Growing evidence indicates that orexins act in the central nervous system also to regulate gastrointestinal functions: animal studies have indeed demonstrated that centrally-injected orexins or endogenously released orexins in the brain stimulates gastric secretion and influence gastrointestinal motility. The subsequent identification of orexins and their receptors in the enteric nervous system (including the myenteric and the submucosal plexuses) as well as in mucosa and smooth muscles has suggested that these neuropeptides may also play a local action. In this view, emerging studies indicate that orexins also exert region-specific contractile or relaxant effects on isolated gut preparations. The aim of the proposed review is to summarize both centrally- and peripherally-mediated actions of orexins on gastrointestinal functions and to discuss the related physiological role on the basis of the most recent findings.

  16. A functional RG equation for the c-function

    DEFF Research Database (Denmark)

    Codello, A.; D'Odorico, G.; Pagani, C.

    2014-01-01

    , local potential approximation and loop expansion. In each case we construct the relative approximate c-function and find it to be consistent with Zamolodchikov's c-theorem. Finally, we present a relation between the c-function and the (matter induced) beta function of Newton's constant, allowing us...... to use heat kernel techniques to compute the RG running of the c-function....

  17. Strange functions in real analysis

    CERN Document Server

    Kharazishvili, AB

    2005-01-01

    Weierstrass and Blancmange nowhere differentiable functions, Lebesgue integrable functions with everywhere divergent Fourier series, and various nonintegrable Lebesgue measurable functions. While dubbed strange or "pathological," these functions are ubiquitous throughout mathematics and play an important role in analysis, not only as counterexamples of seemingly true and natural statements, but also to stimulate and inspire the further development of real analysis.Strange Functions in Real Analysis explores a number of important examples and constructions of pathological functions. After introducing the basic concepts, the author begins with Cantor and Peano-type functions, then moves to functions whose constructions require essentially noneffective methods. These include functions without the Baire property, functions associated with a Hamel basis of the real line, and Sierpinski-Zygmund functions that are discontinuous on each subset of the real line having the cardinality continuum. Finally, he considers e...

  18. Microbial Functional Gene Diversity Predicts Groundwater Contamination and Ecosystem Functioning.

    Science.gov (United States)

    He, Zhili; Zhang, Ping; Wu, Linwei; Rocha, Andrea M; Tu, Qichao; Shi, Zhou; Wu, Bo; Qin, Yujia; Wang, Jianjun; Yan, Qingyun; Curtis, Daniel; Ning, Daliang; Van Nostrand, Joy D; Wu, Liyou; Yang, Yunfeng; Elias, Dwayne A; Watson, David B; Adams, Michael W W; Fields, Matthew W; Alm, Eric J; Hazen, Terry C; Adams, Paul D; Arkin, Adam P; Zhou, Jizhong

    2018-02-20

    Contamination from anthropogenic activities has significantly impacted Earth's biosphere. However, knowledge about how environmental contamination affects the biodiversity of groundwater microbiomes and ecosystem functioning remains very limited. Here, we used a comprehensive functional gene array to analyze groundwater microbiomes from 69 wells at the Oak Ridge Field Research Center (Oak Ridge, TN), representing a wide pH range and uranium, nitrate, and other contaminants. We hypothesized that the functional diversity of groundwater microbiomes would decrease as environmental contamination (e.g., uranium or nitrate) increased or at low or high pH, while some specific populations capable of utilizing or resistant to those contaminants would increase, and thus, such key microbial functional genes and/or populations could be used to predict groundwater contamination and ecosystem functioning. Our results indicated that functional richness/diversity decreased as uranium (but not nitrate) increased in groundwater. In addition, about 5.9% of specific key functional populations targeted by a comprehensive functional gene array (GeoChip 5) increased significantly ( P contamination and ecosystem functioning. This study indicates great potential for using microbial functional genes to predict environmental contamination and ecosystem functioning. IMPORTANCE Disentangling the relationships between biodiversity and ecosystem functioning is an important but poorly understood topic in ecology. Predicting ecosystem functioning on the basis of biodiversity is even more difficult, particularly with microbial biomarkers. As an exploratory effort, this study used key microbial functional genes as biomarkers to provide predictive understanding of environmental contamination and ecosystem functioning. The results indicated that the overall functional gene richness/diversity decreased as uranium increased in groundwater, while specific key microbial guilds increased significantly as

  19. Functional and Phenotypic Plasticity of CD4+ T Cell Subsets

    Directory of Open Access Journals (Sweden)

    Tiffany Caza

    2015-01-01

    Full Text Available The remarkable plasticity of CD4+ T cells allows individuals to respond to environmental stimuli in a context-dependent manner. A balance of CD4+ T cell subsets is critical to mount responses against pathogen challenges to prevent inappropriate activation, to maintain tolerance, and to participate in antitumor immune responses. Specification of subsets is a process beginning in intrathymic development and continuing within the circulation. It is highly flexible to adapt to differences in nutrient availability and the tissue microenvironment. CD4+ T cell subsets have significant cross talk, with the ability to “dedifferentiate” given appropriate environmental signals. This ability is dependent on the metabolic status of the cell, with mTOR acting as the rheostat. Autoimmune and antitumor immune responses are regulated by the balance between regulatory T cells and Th17 cells. When a homeostatic balance of subsets is not maintained, immunopathology can result. CD4+ T cells carry complex roles within tumor microenvironments, with context-dependent immune responses influenced by oncogenic drivers and the presence of inflammation. Here, we examine the signals involved in CD4+ T cell specification towards each subset, interconnectedness of cytokine networks, impact of mTOR signaling, and cellular metabolism in lineage specification and provide a supplement describing techniques to study these processes.

  20. Functional Foods for Women's Health.

    Science.gov (United States)

    Lindeman, Alice K.

    2002-01-01

    Describes functional foods for women's health (foods or food ingredients that provide health benefits beyond basic nutrition), explaining that both whole and modified foods can be included as functional foods. The paper discusses the history, regulation, and promotion of functional foods; consumer interest in functional foods; how to incorporate…