1,435 research outputs found
Digitally Continuous Multivalued Functions, Morphological Operations and Thinning Algorithms
In a recent paper (Escribano et al. in Discrete Geometry for Computer Imagery 2008. Lecture Notes in Computer Science, vol. 4992, pp. 81–92, 2008) we have introduced a notion of continuity in digital spaces which extends the usual notion of digital continuity. Our approach, which uses multivalued functions, provides a better framework to define topological notions, like retractions, in a far more realistic way than by using just single-valued digitally continuous functions.
In this work we develop properties of this family of continuous functions, now concentrating on morphological operations and thinning algorithms. We show that our notion of continuity provides a suitable framework for the basic operations in mathematical morphology: erosion, dilation, closing, and opening. On the other hand, concerning thinning algorithms, we give conditions under which the existence of a retraction F:X⟶X∖D guarantees that D is deletable. The converse is not true, in general, although it is in certain particular important cases which are at the basis of many thinning algorithms
Contexts of diffusion: Adoption of research synthesis in Social Work and Women's Studies
Texts reveal the subjects of interest in research fields, and the values,
beliefs, and practices of researchers. In this study, texts are examined
through bibliometric mapping and topic modeling to provide a birds eye view of
the social dynamics associated with the diffusion of research synthesis methods
in the contexts of Social Work and Women's Studies. Research synthesis texts
are especially revealing because the methods, which include meta-analysis and
systematic review, are reliant on the availability of past research and data,
sometimes idealized as objective, egalitarian approaches to research
evaluation, fundamentally tied to past research practices, and performed with
the goal informing future research and practice. This study highlights the
co-influence of past and subsequent research within research fields;
illustrates dynamics of the diffusion process; and provides insight into the
cultural contexts of research in Social Work and Women's Studies. This study
suggests the potential to further develop bibliometric mapping and topic
modeling techniques to inform research problem selection and resource
allocation.Comment: To appear in proceedings of the 2014 International Conference on
Social Computing, Behavioral-Cultural Modeling, and Prediction (SBP2014
Peripheral Innate Immune Activation Correlates With Disease Severity in GRN Haploinsufficiency.
Objective: To investigate associations between peripheral innate immune activation and frontotemporal lobar degeneration (FTLD) in progranulin gene (GRN) haploinsufficiency. Methods: In this cross-sectional study, ELISA was used to measure six markers of innate immunity (sCD163, CCL18, LBP, sCD14, IL-18, and CRP) in plasma from 30 GRN mutation carriers (17 asymptomatic, 13 symptomatic) and 29 controls. Voxel based morphometry was used to model associations between marker levels and brain atrophy in mutation carriers relative to controls. Linear regression was used to model relationships between plasma marker levels with mean frontal white matter integrity [fractional anisotropy (FA)] and the FTLD modified Clinical Dementia Rating Scale sum of boxes score (FTLD-CDR SB). Results: Plasma sCD163 was higher in symptomatic GRN carriers [mean 321 ng/ml (SD 125)] compared to controls [mean 248 ng/ml (SD 58); p < 0.05]. Plasma CCL18 was higher in symptomatic GRN carriers [mean 56.9 pg/ml (SD 19)] compared to controls [mean 40.5 pg/ml (SD 14); p < 0.05]. Elevation of plasma LBP was associated with white matter atrophy in the right frontal pole and left inferior frontal gyrus (p FWE corrected <0.05) in all mutation carriers relative to controls. Plasma LBP levels inversely correlated with bilateral frontal white matter FA (R2 = 0.59, p = 0.009) in mutation carriers. Elevation in plasma was positively correlated with CDR-FTLD SB (b = 2.27 CDR units/μg LBP/ml plasma, R2 = 0.76, p = 0.003) in symptomatic carriers. Conclusion: FTLD-GRN is associated with elevations in peripheral biomarkers of macrophage-mediated innate immunity, including sCD163 and CCL18. Clinical disease severity and white matter integrity are correlated with blood LBP, suggesting a role for peripheral immune activation in FTLD-GRN
Criteria for the diagnosis of corticobasal degeneration
Current criteria for the clinical diagnosis of pathologically confirmed corticobasal degeneration (CBD) no longer reflect the expanding understanding of this disease and its clinicopathologic correlations. An international consortium of behavioral neurology, neuropsychology, and movement disorders specialists developed new criteria based on consensus and a systematic literature review. Clinical diagnoses (early or late) were identified for 267 nonoverlapping pathologically confirmed CBD cases from published reports and brain banks. Combined with consensus, 4 CBD phenotypes emerged: corticobasal syndrome (CBS), frontal behavioral-spatial syndrome (FBS), nonfluent/agrammatic variant of primary progressive aphasia (naPPA), and progressive supranuclear palsy syndrome (PSPS). Clinical features of CBD cases were extracted from descriptions of 209 brain bank and published patients, providing a comprehensive description of CBD and correcting common misconceptions. Clinical CBD phenotypes and features were combined to create 2 sets of criteria: more specific clinical research criteria for probable CBD and broader criteria for possible CBD that are more inclusive but have a higher chance to detect other tau-based pathologies. Probable CBD criteria require insidious onset and gradual progression for at least 1 year, age at onset ≥50 years, no similar family history or known tau mutations, and a clinical phenotype of probable CBS or either FBS or naPPA with at least 1 CBS feature. The possible CBD category uses similar criteria but has no restrictions on age or family history, allows tau mutations, permits less rigorous phenotype fulfillment, and includes a PSPS phenotype. Future validation and refinement of the proposed criteria are needed
Country, sex, and parent occupational status: Moderators of the continuity of aggression from childhood to adulthood
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109352/1/ab21546.pd
SIRT6 stabilizes DNA-dependent Protein Kinase at chromatin for DNA double-strand break repair
The Sir2 chromatin regulatory factor links maintenance
of genomic stability to life span extension in yeast. The mammalian Sir2
family member SIRT6 has been proposed to have analogous functions, because
SIRT6-deficiency leads to shortened life span and an aging-like
degenerative phenotype in mice, and SIRT6 knockout cells exhibit genomic
instability and DNA damage hypersensitivity. However, the molecular mechanisms
underlying these defects are not fully understood. Here, we show that
SIRT6 forms a macromolecular complex with the DNA double-strand break (DSB)
repair factor DNA-PK (DNA-dependent protein kinase) and promotes DNA DSB
repair. In response to DSBs, SIRT6 associates dynamically with chromatin
and is necessary for an acute decrease in global cellular acetylation
levels on histone H3 Lysine 9. Moreover, SIRT6 is required for
mobilization of the DNA-PK catalytic subunit (DNA-PKcs) to chromatin in response
to DNA damage and stabilizes DNA-PKcs at chromatin adjacent to an induced
site-specific DSB. Abrogation of these SIRT6 activities leads to impaired
resolution of DSBs. Together, these findings elucidate a mechanism whereby
regulation of dynamic interaction of a DNA repair factor with chromatin
impacts on the efficiency of repair, and establish a link between chromatin
regulation, DNA repair, and a mammalian Sir2 factor
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