620 research outputs found
Nullification functors and the homotopy type of the classifying space for proper bundles
Let G be a discrete group for which the classifying space for proper
G-actions is finite-dimensional. We find a space W such that for any such G,
the classifying space PBG for proper G-bundles has the homotopy type of the
W-nullification of BG. We use this to deduce some results concerning PBG and in
some cases where there is a good model for PBG we obtain information about the
BZ/p-nullification of BG.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol5/agt-5-46.abs.htm
Homotopical resolutions associated to deformable adjunctions
Given an adjunction connecting reasonable categories with weak equivalences,
we define a new derived bar and cobar construction associated to the
adjunction. This yields homotopical models of the completion and cocompletion
associated to the monad and comonad of the adjunction. We discuss applications
of these resolutions to spectral sequences for derived completions and
Goodwillie calculus in general model categories.Comment: 22 pages; v2 is the final journal version, with expository
improvements suggested by the refere
Validity, reliability, acceptability, and utility of the Social Inclusion Questionnaire User Experience (SInQUE): a clinical tool to facilitate social inclusion amongst people with severe mental health problems.
BACKGROUND: Individuals with severe mental health problems are at risk of social exclusion, which may complicate their recovery. Mental health and social care staff have, until now, had no valid or reliable way of assessing their clients' social inclusion. The Social Inclusion Questionnaire User Experience (SInQUE) was developed to address this. It assesses five domains: social integration; productivity; consumption; access to services; and political engagement, in the year prior to first psychiatric admission (T1) and the year prior to interview (T2) from which a total score at each time point can be calculated. AIMS: To establish the validity, reliability, and acceptability of the SInQUE in individuals with a broad range of psychiatric diagnoses receiving care from community mental health services and its utility for mental health staff. METHOD: Participants were 192 mental health service users with psychosis, personality disorder, or common mental disorder (e.g., depression, anxiety) who completed the SInQUE alongside other validated outcome measures. Test-retest reliability was assessed in a sub-sample of 30 participants and inter-rater reliability was assessed in 11 participants. SInQUE ratings of 28 participants were compared with those of a sibling with no experience of mental illness to account for shared socio-cultural factors. Acceptability and utility of the tool were assessed using completion rates and focus groups with staff. RESULTS: The SInQUE demonstrated acceptable convergent validity. The total score and the Social Integration domain score were strongly correlated with quality of life, both in the full sample and in the three diagnostic groups. Discriminant validity and test-retest reliability were established across all domains, although the test-retest reliability on scores for the Service Access and Political Engagement domains prior to first admission to hospital (T1) was lower than other domains. Inter-rater reliability was excellent for all domains at T1 and T2. CONCLUSIONS: The component of the SInQUE that assesses current social inclusion has good psychometric properties and can be recommended for use by mental health staff
Topological Hochschild homology of Thom spectra and the free loop space
We describe the topological Hochschild homology of ring spectra that arise as
Thom spectra for loop maps f: X->BF, where BF denotes the classifying space for
stable spherical fibrations. To do this, we consider symmetric monoidal models
of the category of spaces over BF and corresponding strong symmetric monoidal
Thom spectrum functors. Our main result identifies the topological Hochschild
homology as the Thom spectrum of a certain stable bundle over the free loop
space L(BX). This leads to explicit calculations of the topological Hochschild
homology for a large class of ring spectra, including all of the classical
cobordism spectra MO, MSO, MU, etc., and the Eilenberg-Mac Lane spectra HZ/p
and HZ.Comment: 58 page
Duality and Pro-Spectra
Cofiltered diagrams of spectra, also called pro-spectra, have arisen in
diverse areas, and to date have been treated in an ad hoc manner. The purpose
of this paper is to systematically develop a homotopy theory of pro-spectra and
to study its relation to the usual homotopy theory of spectra, as a foundation
for future applications. The surprising result we find is that our homotopy
theory of pro-spectra is Quillen equivalent to the opposite of the homotopy
theory of spectra. This provides a convenient duality theory for all spectra,
extending the classical notion of Spanier-Whitehead duality which works well
only for finite spectra. Roughly speaking, the new duality functor takes a
spectrum to the cofiltered diagram of the Spanier-Whitehead duals of its finite
subcomplexes. In the other direction, the duality functor takes a cofiltered
diagram of spectra to the filtered colimit of the Spanier-Whitehead duals of
the spectra in the diagram. We prove the equivalence of homotopy theories by
showing that both are equivalent to the category of ind-spectra (filtered
diagrams of spectra).
To construct our new homotopy theories, we prove a general existence theorem
for colocalization model structures generalizing known results for cofibrantly
generated model categories.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol4/agt-4-34.abs.htm
Impact of Dementia on Mindful Attention: a Cross-Sectional Comparison of People with Dementia and Those Without
Mindfulness-based interventions have been suggested as ways of improving mood and cognition in people with dementia. Existing findings suggest possible benefit from a mindfulness-based group intervention. However, it is unclear whether any structured group activity (rather than mindfulness practice per se) would produce the same benefits, particularly since dementia may impact mindful attention ability. Consequently, we investigated the potential impact of having dementia on mindful attention. We compared the performance of 34 people with dementia recruited from memory services with 55 community-recruited older people on measures of mindful attention, cognitive flexibility, and cognition, as well as putative nuisance variates of depression, anxiety and premorbid intellectual ability. The groups differed significantly on a range of demographic characteristics and some neuropsychological and mood measures. However, neither the primary prediction (that there would be a large effect size difference between groups, with people with dementia performing significantly more poorly on a measure of mindful attention to the breath), nor the secondary prediction (that performance on this measure would positively correlate with measures of executive function and overall cognition) was supported. We concluded that a diagnosis of dementia may not have a large effect on mindful attention, with consequent implications for future research
FGDB: Database of Follicle Stimulating Hormone Glycans
Glycomics, the study of the entire complement of sugars of an organism has received significant attention in the recent past due to the advances made in high throughput mass spectrometry technologies. These analytical advancements have facilitated the characterization of glycans associated with the follicle-stimulating hormones (FSH), which play a central role in the human reproductive system both in males and females utilizing regulating gonadal (testicular and ovarian) functions. The irregularities in FSH activity are also directly linked with osteoporosis. The glycoanalytical studies have been tremendously helpful in understanding the biological roles of FSH. Subsequently, the increasing number of characterized FSH glycan structures and related glycoform data has thrown a challenge to the glycoinformatics community in terms of data organization, storage and access. Also, a user-friendly platform is needed for providing easy access to the database and performing integrated analysis using a high volume of experimental data to accelerate FSH-focused research. FSH Glycans DataBase (FGDB) serves as a comprehensive and unique repository of structures, features, and related information of glycans associated with FSH. Apart from providing multiple search options, the database also facilitates an integrated user-friendly interface to perform the glycan abundance and comparative analyses using experimental data. The automated integrated pipelines present the possible structures of glycans and variants of FSH based on the input data, and allow the user to perform various analyses. The potential application of FGDB will significantly help both glycoinformaticians as well as wet-lab researchers to stimulate the research in this area. FGDB web access: https://fgdb.unmc.edu/
Locally class-presentable and class-accessible categories
We generalize the concepts of locally presentable and accessible categories.
Our framework includes such categories as small presheaves over large
categories and ind-categories. This generalization is intended for applications
in the abstract homotopy theory
An almost full embedding of the category of graphs into the category of abelian groups
We construct an embedding G of the category of graphs into the category of
abelian groups such that for graphs X and Y we have Hom(GX,GY)=Z[Hom(X,Y)], the
free abelian group whose basis is the set Hom(X,Y). The isomorphism is
functorial in X and Y. The existence of such an embedding implies that,
contrary to a common belief, the category of abelian groups is as complex and
comprehensive as any other concrete category. We use this embedding to settle
an old problem of Isbell whether every full subcategory of the category of
abelian groups, which is closed under limits, is reflective. A positive answer
turns out to be equivalent to weak Vopenka's principle, a large cardinal axiom
which is not provable but believed to be consistent with standard set theory.
Several known constructions in the category of abelian groups are obtained as
quick applications of the embedding. In the revised version we add some
consequences to the Hovey-Palmieri-Stricland problem about existence of
arbitrary localizations in a stable homotopy categoryComment: 20 page
The de Rham homotopy theory and differential graded category
This paper is a generalization of arXiv:0810.0808. We develop the de Rham
homotopy theory of not necessarily nilpotent spaces, using closed dg-categories
and equivariant dg-algebras. We see these two algebraic objects correspond in a
certain way. We prove an equivalence between the homotopy category of schematic
homotopy types and a homotopy category of closed dg-categories. We give a
description of homotopy invariants of spaces in terms of minimal models. The
minimal model in this context behaves much like the Sullivan's minimal model.
We also provide some examples. We prove an equivalence between fiberwise
rationalizations and closed dg-categories with subsidiary data.Comment: 47 pages. final version. The final publication is available at
http://www.springerlink.co
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