306 research outputs found

    A functional-cognitive framework for attitude research

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    In attitude research, behaviours are often used as proxies for attitudes and attitudinal processes. This practice is problematic because it conflates the behaviours that need to be explained (explanandum) with the mental constructs that are used to explain these behaviours (explanans). In the current chapter we propose a meta-theoretical framework that resolves this problem by distinguishing between two levels of analysis. According to the proposed framework, attitude research can be conceptualised as the scientific study of evaluation. Evaluation is defined not in terms of mental constructs but in terms of elements in the environment, more specifically, as the effect of stimuli on evaluative responses. From this perspective, attitude research provides answers to two questions: (1) Which elements in the environment moderate evaluation? (2) What mental processes and representations mediate evaluation? Research on the first question provides explanations of evaluative responses in terms of elements in the environment (functional level of analysis); research on the second question offers explanations of evaluation in terms of mental processes and representations (cognitive level of analysis). These two levels of analysis are mutually supportive, in that better explanations at one level lead to better explanations at the other level. However, their mutually supportive relation requires a clear distinction between the concepts of their explanans and explanandum, which are conflated if behaviours are treated as proxies for mental constructs. The value of this functional-cognitive framework is illustrated by applying it to four central questions of attitude research

    Reduced order models for control of fluids using the Eigensystem Realization Algorithm

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    In feedback flow control, one of the challenges is to develop mathematical models that describe the fluid physics relevant to the task at hand, while neglecting irrelevant details of the flow in order to remain computationally tractable. A number of techniques are presently used to develop such reduced-order models, such as proper orthogonal decomposition (POD), and approximate snapshot-based balanced truncation, also known as balanced POD. Each method has its strengths and weaknesses: for instance, POD models can behave unpredictably and perform poorly, but they can be computed directly from experimental data; approximate balanced truncation often produces vastly superior models to POD, but requires data from adjoint simulations, and thus cannot be applied to experimental data. In this paper, we show that using the Eigensystem Realization Algorithm (ERA) \citep{JuPa-85}, one can theoretically obtain exactly the same reduced order models as by balanced POD. Moreover, the models can be obtained directly from experimental data, without the use of adjoint information. The algorithm can also substantially improve computational efficiency when forming reduced-order models from simulation data. If adjoint information is available, then balanced POD has some advantages over ERA: for instance, it produces modes that are useful for multiple purposes, and the method has been generalized to unstable systems. We also present a modified ERA procedure that produces modes without adjoint information, but for this procedure, the resulting models are not balanced, and do not perform as well in examples. We present a detailed comparison of the methods, and illustrate them on an example of the flow past an inclined flat plate at a low Reynolds number.Comment: 22 pages, 7 figure

    Group evaluations as self-group distancing:Ingroup typicality moderates evaluative intergroup bias in stigmatized groups

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    Outgroup favoritism among members of stigmatized groups can be seen as a form of self-group distancing. We examined how intergroup evaluations in stigmatized groups vary as a function of ingroup typicality. In Studies 1 and 2, Black participants (N = 125,915;N = 766) more strongly preferred light-skinned or White relative to dark-skinned or Black individuals the lighter their own skin tone. In Study 3, overweight participants (N = 147,540) more strongly preferred normal-weight relative to overweight individuals the lower their own body weight. In Study 4, participants with disabilities (N = 35,058) more strongly preferred non-disabled relative to disabled individuals the less visible they judged their own disability. Relationships between ingroup typicality and intergroup evaluations were at least partially mediated by ingroup identification (Studies 2 and 3). A meta-analysis across studies yielded an average effect size ofr= .12. Furthermore, higher ingroup typicality was related to both ingroup and outgroup evaluations. We discuss ingroup typicality as an individual constraint to self-group distancing among stigmatized group members and its relation to intergroup evaluations

    Assessment and treatment of distorted schemas in sexual offenders

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    The aim of this review is to examine the literature related to the assessment and treatment of sex offenders’ distorted schemas. Where appropriate, the review draws upon current insights from the field of social cognition to aid in the critical evaluation of the findings. First, the review considers the various different methodologies for assessing distorted schemas, discussing their strengths and limitations. Second, the review examines the work related to the treatment of sex offenders’ schemas. Suggestions for future research, and the implications for clinical practice, are highlighted in the article

    Changing deep-rooted implicit evaluation in the blink of an eye: negative verbal information shifts automatic liking of Gandhi

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    It is often assumed that, once established, spontaneous or implicit evaluations are resistant to immediate change. Recent research contradicts this theoretical stance, showing that a person’s implicit evaluations of an attitude object can be changed rapidly in the face of new counter-attitudinal information. Importantly, it remains unknown whether such changes can also occur for deep-rooted implicit evaluations of well-known attitude objects. We address this question by examining whether the acquisition of negative information changes implicit evaluations of a well-known positive historic figure: Mahatma Gandhi. We report three experiments showing rapid changes in implicit evaluations of Gandhi as measured with an Affect Misattribution Procedure and Evaluative Priming Task but not with an Implicit Association Test (IAT). These findings suggest that implicit evaluations based on deep-rooted representations are subjective to rapid changes in the face of expectancy-violating information, while pointing to limitations of the IAT for assessing such changes

    Structures of SRP54 and SRP19, the Two Proteins that Organize the Ribonucleic Core of the Signal Recognition Particle from Pyrococcus furiosus

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    In all organisms the Signal Recognition Particle (SRP), binds to signal sequences of proteins destined for secretion or membrane insertion as they emerge from translating ribosomes. In Archaea and Eucarya, the conserved ribonucleoproteic core is composed of two proteins, the accessory protein SRP19, the essential GTPase SRP54, and an evolutionarily conserved and essential SRP RNA. Through the GTP-dependent interaction between the SRP and its cognate receptor SR, ribosomes harboring nascent polypeptidic chains destined for secretion are dynamically transferred to the protein translocation apparatus at the membrane. We present here high-resolution X-ray structures of SRP54 and SRP19, the two RNA binding components forming the core of the signal recognition particle from the hyper-thermophilic archaeon Pyrococcus furiosus (Pfu). The 2.5 Γ… resolution structure of free Pfu-SRP54 is the first showing the complete domain organization of a GDP bound full-length SRP54 subunit. In its ras-like GTPase domain, GDP is found tightly associated with the protein. The flexible linker that separates the GTPase core from the hydrophobic signal sequence binding M domain, adopts a purely Ξ±-helical structure and acts as an articulated arm allowing the M domain to explore multiple regions as it scans for signal peptides as they emerge from the ribosomal tunnel. This linker is structurally coupled to the GTPase catalytic site and likely to propagate conformational changes occurring in the M domain through the SRP RNA upon signal sequence binding. Two different 1.8 Γ… resolution crystal structures of free Pfu-SRP19 reveal a compact, rigid and well-folded protein even in absence of its obligate SRP RNA partner. Comparison with other SRP19β€’SRP RNA structures suggests the rearrangement of a disordered loop upon binding with the RNA through a reciprocal induced-fit mechanism and supports the idea that SRP19 acts as a molecular scaffold and a chaperone, assisting the SRP RNA in adopting the conformation required for its optimal interaction with the essential subunit SRP54, and proper assembly of a functional SRP

    High-Resolution Phenotypic Profiling Defines Genes Essential for Mycobacterial Growth and Cholesterol Catabolism

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    The pathways that comprise cellular metabolism are highly interconnected, and alterations in individual enzymes can have far-reaching effects. As a result, global profiling methods that measure gene expression are of limited value in predicting how the loss of an individual function will affect the cell. In this work, we employed a new method of global phenotypic profiling to directly define the genes required for the growth of Mycobacterium tuberculosis. A combination of high-density mutagenesis and deep-sequencing was used to characterize the composition of complex mutant libraries exposed to different conditions. This allowed the unambiguous identification of the genes that are essential for Mtb to grow in vitro, and proved to be a significant improvement over previous approaches. To further explore functions that are required for persistence in the host, we defined the pathways necessary for the utilization of cholesterol, a critical carbon source during infection. Few of the genes we identified had previously been implicated in this adaptation by transcriptional profiling, and only a fraction were encoded in the chromosomal region known to encode sterol catabolic functions. These genes comprise an unexpectedly large percentage of those previously shown to be required for bacterial growth in mouse tissue. Thus, this single nutritional change accounts for a significant fraction of the adaption to the host. This work provides the most comprehensive genetic characterization of a sterol catabolic pathway to date, suggests putative roles for uncharacterized virulence genes, and precisely maps genes encoding potential drug targets

    Identification of genes required for soil survival in Burkholderia thailandensis by transposon-directed insertion site sequencing.

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    Transposon-directed insertion site sequencing was used to identify genes required by Burkholderia thailandensis to survive in plant/soil microcosms. A total of 1,153 genetic loci fulfilled the criteria as being likely to encode survival characteristics. Of these, 203 (17.6 %) were associated with uptake and transport systems; 463 loci (40.1 %) coded for enzymatic properties, 99 of these (21.4 %) had reduction/oxidation functions; 117 (10.1 %) were gene regulation or sensory loci; 61 (5.3 %) encoded structural proteins found in the cell envelope or with enzymatic activities related to it, distinct from these, 46 (4.0 %) were involved in chemotaxis and flagellum, or pilus synthesis; 39 (3.4 %) were transposase enzymes or were bacteriophage-derived; and 30 (2.6 %) were involved in the production of antibiotics or siderophores. Two hundred and twenty genes (19.1 %) encoded hypothetical proteins or those of unknown function. Given the importance of motility and pilus formation in microcosm persistence the nature of the colonization of the rhizosphere was examined by confocal microscopy. Wild type B. thailandensis expressing red fluorescent protein was inoculated into microcosms. Even though the roots had been washed, the bacteria were still present but they were motile with no attachment having taken place, perhaps being retained in a biofilm
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