1,609 research outputs found

    Functional Maps Representation on Product Manifolds

    Get PDF
    We consider the tasks of representing, analyzing and manipulating maps between shapes. We model maps as densities over the product manifold of the input shapes; these densities can be treated as scalar functions and therefore are manipulable using the language of signal processing on manifolds. Being a manifold itself, the product space endows the set of maps with a geometry of its own, which we exploit to define map operations in the spectral domain; we also derive relationships with other existing representations (soft maps and functional maps). To apply these ideas in practice, we discretize product manifolds and their Laplace--Beltrami operators, and we introduce localized spectral analysis of the product manifold as a novel tool for map processing. Our framework applies to maps defined between and across 2D and 3D shapes without requiring special adjustment, and it can be implemented efficiently with simple operations on sparse matrices.Comment: Accepted to Computer Graphics Foru

    Field independence associates with mathematics and science performance in 5- to 10-year-olds after accounting for domain-general factors

    Get PDF
    Field independence describes the extent to which individuals are influenced by context when trying to identify embedded targets. It associates with cognitive functioning and is a predictor of academic achievement. However, little is known about the neural and cognitive underpinnings of field independence which lead to these associations. Here we investigated behavioural associations between two measures of field independence (Children’s Embedded Figures Test (CEFT) and Design Organisation Test (DOT)) and performance on mathematics (reasoning and written arithmetic) and science tests (reasoning and scientific inquiry) in 135 children aged 5-10 years. There were strong associations between field independence and mathematics and science, which were largely explained by individual differences in age, IQ, and verbal working memory. However, regression analyses indicated that after controlling for these variables, the CEFT explained additional variance on the mathematical reasoning and science tests, whereas the DOT predicted unique variance on the written arithmetic test

    Immune Sensitization to the 60 kD Heat Shock Protein and Pregnancy Outcome

    Get PDF
    Heat shock proteins are highly conserved proteins present in organisms ranging from bacteria to man. They are both dominant microbial immunogens and among the first proteins produced during mammalian embryo development. Since bacterial and human heat shock proteins share a high degree of amino acid sequence homology, it has been suggested that sensitization to bacterial heat shock proteins during an infection may result in autoimmunity to human heat shock proteins. Infertile couples seeking in vitro fertilization (IVF) may have been previously sensitized to bacterial heat shock proteins as a consequence of an asymptomatic upper genital tract infection. Due to daily clinical monitoring and precisely timed fertilization these patients are an ideal study group to investigate the effect of prior sensitization to heat shock proteins on preimplantation embryo development and implantation failure. Immune sensitization at the level of the cervix to the 60 kD heat shock protein (hsp60) has been associated with implantation failure in some IVF patients. Similarly, the highest prevalence of circulating hsp60 antibodies among IVF patients was found in the sera of women whose embryos failed to develop in vitro. To more directly assess whether humoral immunity to hsp60 influenced in vitro embryo development, a mouse embryo culture model was established. Monoclonal antibody to mammalian hsp60 markedly impaired mouse embryo development in vitro. These data suggest that immune sensitization to human hsp60, possibly developed as a consequence of infection, may adversely affect pregnancy outcome in some patients

    Heat shock protein expression during gametogenesis and embryogenesis.

    Get PDF
    When cells are subjected to various stress factors, they increase the production of a group of proteins called heat shock proteins (hsp). Heat shock proteins are highly conserved proteins present in organisms ranging from bacteria to man. Heat shock proteins enable cells to survive adverse environmental conditions by preventing protein denaturation. Thus the physiological and pathological potential of hsps is enormous and has been studied widely over the past two decades. The presence or absence of hsps influences almost every aspect of reproduction. They are among the first proteins produced during mammalian embryo development. In this report, the production of hsps in gametogenesis and early embryo development is described. It has been suggested that prolonged and asymptomatic infections trigger immunity to microbial hsp epitopes that are also expressed in man. This may be relevant for human reproduction, since many couples with fertility problems have had a previous genital tract infection. Antibodies to bacterial and human hsps are present at high titers in sera of many patients undergoing in vitro fertilization. In a mouse embryo culture model, these antibodies impaired the mouse embryo development at unique developmental stages. The gross morphology of these embryos resembled cells undergoing apoptosis. The TUNEL (terminal deoxynucleotidyl transferase-mediated X-dUTP nick end labeling) staining pattern, which is a common marker of apoptosis, revealed that embryos cultured in the presence of hsp antibodies stained TUNEL-positive more often than unexposed embryos. These data extend preexisting findings showing the detrimental effect of immune sensitization to hsps on embryo development

    A survey of partial differential equations in geometric design

    Get PDF
    YesComputer aided geometric design is an area where the improvement of surface generation techniques is an everlasting demand since faster and more accurate geometric models are required. Traditional methods for generating surfaces were initially mainly based upon interpolation algorithms. Recently, partial differential equations (PDE) were introduced as a valuable tool for geometric modelling since they offer a number of features from which these areas can benefit. This work summarises the uses given to PDE surfaces as a surface generation technique togethe

    Culture and personality revisited: Behavioral profiles and within‐person stability in interdependent (vs. independent) social orientation and holistic (vs. analytic) cognitive style

    Full text link
    ObjectiveWe test the proposition that both social orientation and cognitive style are constructs consisting of loosely related attributes. Thus, measures of each construct should weakly correlate among themselves, forming intraindividually stable profiles across measures over time.MethodStudy 1 tested diverse samples of Americans (N = 233) and Japanese (N = 433) with a wide range of measures of social orientation and cognitive style to explore correlations among these measures in a cross‐cultural context, using demographically heterogeneous samples. Study 2 recruited a new sample of 485 Americans and Canadians and examined their profiles on measures of social orientation and cognitive style twice, one month apart, to assess the stability of individual profiles using these variables.ResultsDespite finding typical cross‐cultural differences, Study 1 demonstrated negligible correlations both among measures of social orientation and among measures of cognitive style. Study 2 demonstrated stable intraindividual behavioral profiles across measures capturing idiosyncratic patters of social orientation and cognitive style, despite negligible correlations among the same measures.ConclusionThe results provide support for the behavioral profile approach to conceptualizing social orientation and cognitive style, highlighting the need to assess intraindividual stability of psychological constructs in cross‐cultural research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162694/2/jopy12536_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162694/1/jopy12536.pd

    Changes in rod and frame test scores recorded in schoolchildren during development--a longitudinal study.

    Get PDF
    The Rod and Frame Test has been used to assess the degree to which subjects rely on the visual frame of reference to perceive vertical (visual field dependence-independence perceptual style). Early investigations found children exhibited a wide range of alignment errors, which reduced as they matured. These studies used a mechanical Rod and Frame system, and presented only mean values of grouped data. The current study also considered changes in individual performance. Changes in rod alignment accuracy in 419 school children were measured using a computer-based Rod and Frame test. Each child was tested at school Grade 2 and retested in Grades 4 and 6. The results confirmed that children displayed a wide range of alignment errors, which decreased with age but did not reach the expected adult values. Although most children showed a decrease in frame dependency over the 4 years of the study, almost 20% had increased alignment errors suggesting that they were becoming more frame-dependent. Plots of individual variation (SD) against mean error allowed the sample to be divided into 4 groups; the majority with small errors and SDs; a group with small SDs, but alignments clustering around the frame angle of 18°; a group showing large errors in the opposite direction to the frame tilt; and a small number with large SDs whose alignment appeared to be random. The errors in the last 3 groups could largely be explained by alignment of the rod to different aspects of the frame. At corresponding ages females exhibited larger alignment errors than males although this did not reach statistical significance. This study confirms that children rely more heavily on the visual frame of reference for processing spatial orientation cues. Most become less frame-dependent as they mature, but there are considerable individual differences

    Global and local perceptual style, field-independence, and central coherence: An attempt at concept validation.

    Get PDF
    Historically, the concepts of field-independence, closure flexibility, and weak central coherence have been used to denote a locally, rather globally, dominated perceptual style. To date, there has been little attempt to clarify the relationship between these constructs, or to examine the convergent validity of the various tasks purported to measure them. To address this, we administered 14 tasks that have been used to study visual perceptual styles to a group of 90 neuro-typical adults. The data were subjected to exploratory factor analysis. We found evidence for the existence of a narrowly defined weak central coherence (field-independence) factor that received loadings from only a few of the tasks used to operationalise this concept. This factor can most aptly be described as representing the ability to dis-embed a simple stimulus from a more complex array. The results suggest that future studies of perceptual styles should include tasks whose theoretical validity is empirically verified, as such validity cannot be established merely on the basis of a priori task analysis. Moreover, the use of multiple indices is required to capture the latent dimensions of perceptual styles reliably

    Local and global processing in savant artists with autism

    Get PDF
    Abstract. We explored the hypothesis that an enhanced local processing style is characteristic of both art and autism spectrum disorder (ASD) by examining local and global processing in savant artists with ASD. Specifically, savant artists were compared against non-talented individuals with ASD or mild/moderate learning difficulties (MLD), as well as artistically talented or non- talented students, on the block-design task and meaningful and abstract versions of the embedded figures test (EFT). Results demonstrated that there were no significant differences between the meaningful and abstract versions of the EFT, in any of the groups. This suggests that the primary process governing performance on this task was perceptual (local), rather than conceptual (global). More interestingly, the savant artists performed above the level of the ASD and MLD groups on the block-design test, but not the EFT. Despite both the block-design task and the EFT measuring local processing abilities, we suggest that this result is due to the block-design task being an active construction task (requiring the conversion of a visual input into a motor output), whereas the EFT is a passive recognition task. Therefore, although an enhanced local processing style is an important aspect of savant artistic talent, motor control also appears to be a necessary skill

    Effects of Cocaine-Kindling on the Expression of NMDA Receptors and Glutamate Levels in Mouse Brain

    Get PDF
    In the present study we examined the effects of cocaine seizure kindling on the expression of NMDA receptors and levels of extracellular glutamate in mouse brain. Quantitative autoradiography did not reveal any changes in binding of [3H] MK-801 to NMDA receptors in several brain regions. Likewise, in situ hybridization and Western blotting revealed no alteration in expression of the NMDA receptor subunits, NR1 and NR2B. Basal overflow of glutamate in the ventral hippocampus determined by microdialysis in freely moving animals also did not differ between cocaine-kindled and control groups. Perfusion with the selective excitatory amino acid transporter inhibitor, pyrrolidine-2,4-dicarboxylic acid (tPDC, 0.6 mM), increased glutamate overflow confirming transport inhibition. Importantly, KCl-evoked glutamate overflow under tPDC perfusion was significantly higher in cocaine-kindled mice than in control mice. These data suggest that enhancement of depolarization stimulated glutamate release may be one of the mechanisms underlying the development of increased seizure susceptibility after cocaine kindling
    corecore