329 research outputs found
Multiple Mirror Manifolds and Topology Change in String Theory
We use mirror symmetry to establish the first concrete arena of spacetime
topology change in string theory. In particular, we establish that the {\it
quantum theories} based on certain nonlinear sigma models with topologically
distinct target spaces can be smoothly connected even though classically a
physical singularity would be encountered. We accomplish this by rephrasing the
description of these nonlinear sigma models in terms of their mirror manifold
partners--a description in which the full quantum theory can be described
exactly using lowest order geometrical methods.
We establish that, for the known class of mirror manifolds, the moduli space
of the corresponding conformal field theory requires not just two but {\it
numerous} topologically distinct Calabi-Yau manifolds for its geometric
interpretation. A {\it single} family of continuously connected conformal
theories thereby probes a host of topologically distinct geometrical spaces
giving rise to {\it multiple mirror manifolds}.Comment: 18 pp., (uses harvmac and epsf) (Missing reference added.
The Maine Annex, vol. 1, no. 2
The Maine Annex, published by the students of the University of Maine at the Brunswick Campus, was launched January 10, 1947. Editors introduced the publication as the product of a group of progressive students attending the Brunswick Campus. The goal of the publication, according to editors, was to tell the story of our life on this campus. The four-page, tabloid-sized paper included display advertising from area businesses. Stories in this issue of The Maine Annex are news items of interest to World War II Veterans, including international news from Europe and tips regarding the filing of federal paperwork to secure veterans benefits
The Maine Annex, vol. 1, no. 3
The Maine Annex, published by the students of the University of Maine at the Brunswick Campus, was launched January 10, 1947. Editors introduced the publication as the product of a group of progressive students attending the Brunswick Campus. The goal of the publication, according to editors, was to tell the story of our life on this campus. The four-page, tabloid-sized paper included display advertising from area businesses. Among front page headlines is: Pres. Hauck Addresses Maine Annex Students. President Hauck States That Education Is Now Recognized As One Of The Prime Factors In Building World Peace
Reduction of Low-Thrust Continuous Controls for Trajectory Dynamics
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76670/1/AIAA-40619-128.pd
Classification of singular Q-homology planes. I. Structure and singularities
A Q-homology plane is a normal complex algebraic surface having trivial
rational homology. We obtain a structure theorem for Q-homology planes with
smooth locus of non-general type. We show that if a Q-homology plane contains a
non-quotient singularity then it is a quotient of an affine cone over a
projective curve by an action of a finite group respecting the set of lines
through the vertex. In particular, it is contractible, has negative Kodaira
dimension and only one singular point. We describe minimal normal completions
of such planes.Comment: improved results from Ph.D. thesis (University of Warsaw, 2009), 25
pages, to appear in Israel J. Mat
The benefit of directly comparing autism and schizophrenia for revealing mechanisms of social cognitive impairment
Autism and schizophrenia share a history of diagnostic conflation that was not definitively resolved until the publication of the DSM-III in 1980. Though now recognized as heterogeneous disorders with distinct developmental trajectories and dissociative features, much of the early nosological confusion stemmed from apparent overlap in certain areas of social dysfunction. In more recent years, separate but substantial literatures have accumulated for autism and schizophrenia demonstrating that abnormalities in social cognition directly contribute to the characteristic social deficits of both disorders. The current paper argues that direct comparison of social cognitive impairment can highlight shared and divergent mechanisms underlying pathways to social dysfunction, a process that can provide significant clinical benefit by informing the development of tailored treatment efforts. Thus, while the history of diagnostic conflation between autism and schizophrenia may have originated in similarities in social dysfunction, the goal of direct comparisons is not to conflate them once again but rather to reveal distinctions that illuminate disorder-specific mechanisms and pathways that contribute to social cognitive impairment
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Reading the mind in the eyes and cognitive ability in schizophrenia- and autism spectrum disorders
Background
Schizophrenia (SZ) and autism spectrum disorders (ASD) are characterized by difficulties in theory of mind (ToM). We examined group differences in performance on a ToM-related test and associations with an estimated IQ.
Methods
Participants [N = 1227, SZ (n = 563), ASD (n = 159), and controls (n = 505), 32.2% female] completed the Reading the Mind in the Eyes Test (RMET) and assessments of cognitive ability. Associations between IQ and group on RMET were investigated with regression analyses.
Results
SZ (d = 0.73, p < 0.001) and ASD (d = 0.37, p < 0.001) performed significantly worse on the RMET than controls. SZ performed significantly worse than ASD (d = 0.32, p = 0.002). Adding IQ to the model, SZ (d = 0.60, p < 0.001) and ASD (d = 0.44, p < 0.001) continued to perform significantly worse than controls, but no longer differed from each other (d = 0.13, p = 0.30). Small significant negative correlations between symptom severity and RMET performance were found in SZ (PANSS positive: r = β0.10, negative: r = β0.11, both p < 0.05). A small non-significant negative correlation was found for Autism Diagnostic Observation Schedule scores and RMET in ASD (r = β0.08, p = 0.34).
Conclusions
SZ and ASD are characterized by impairments in RMET. IQ contributed significantly to RMET performance and accounted for group differences in RMET between SZ and ASD. This suggests that non-social cognitive ability needs to be included in comparative studies of the two disorders
The Molecular Epidemiology of Clostridioides difficile Infection in Central India: A Prospective Observational Cohort Study
This prospective observational cohort study aimed to establish and compare baseline rates of Clostridioides difficile infection (CDI) in community and hospitalized patients in Nagpur and rural Melghat Maharashtra, including adults aged β₯18 years with a diagnosis of diarrhoea as defined as 3 or more loose stools in a 24 h period. All diarrhoeal samples were tested for CDI using the C. diff Quik Chek Complete enzyme immunoassay. C. difficile-positive stool samples were characterised by toxigenic culture, antimicrobial susceptibility testing and PCR ribotyping. C. difficile testing was performed on 1683 patients with acute diarrhoea. A total of 54 patients (3.21%; 95% CI: 2.42β4.17) tested positive for both the GDH antigen and free toxin. The risk factors for CDI included the presence of co-morbidities, antibiotic usage, and immunosuppression. The detected PCR ribotypes included 053-16, 017, 313, 001, 107, and 216. Our findings show that toxigenic C. difficile is an important but neglected aetiologic agent of infective diarrhoea in Central India. These results underscore the need to enhance the awareness and testing of patients with diarrhoea in India regarding the presence of toxigenic C. difficile, particularly in high-risk individuals with multiple co-morbidities, immunosuppression, and recent or ongoing antibiotic exposure or hospitalization
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