5,091 research outputs found
Disruption to control network function correlates with altered dynamic connectivity in the wider autism spectrum.
Autism is a common developmental condition with a wide, variable range of co-occurring neuropsychiatric symptoms. Contrasting with most extant studies, we explored whole-brain functional organization at multiple levels simultaneously in a large subject group reflecting autism's clinical diversity, and present the first network-based analysis of transient brain states, or dynamic connectivity, in autism. Disruption to inter-network and inter-system connectivity, rather than within individual networks, predominated. We identified coupling disruption in the anterior-posterior default mode axis, and among specific control networks specialized for task start cues and the maintenance of domain-independent task positive status, specifically between the right fronto-parietal and cingulo-opercular networks and default mode network subsystems. These appear to propagate downstream in autism, with significantly dampened subject oscillations between brain states, and dynamic connectivity configuration differences. Our account proposes specific motifs that may provide candidates for neuroimaging biomarkers within heterogeneous clinical populations in this diverse condition
National Foreclosure Mitigation Counseling Program Evaluation: Final Report, Rounds 3 Through 5
The Urban Institute completed a four-year evaluation of Rounds 3 through 5 of the National Foreclosure Mitigation Counseling (NFMC) program. Using a representative NFMC sample of 137,000 loans and a comparison non-NFMC sample of 103,000 loans, the Urban Institute was able to employ robust statistical techniques to isolate the impact of NFMC counseling on loan performance through June 2013.The final evaluation of Rounds 3 through 5 conducted by Urban Institute indicates that the NFMC program continues to have positive effects for homeowners participating in the program Counseled homeowners were more likely to cure a serious delinquency or foreclosure with a modification or other type cure, stay current after obtaining a cure, and for NFMC clients who cured a serious delinquency, avoid foreclosure altogether
Citizen science and natural resource governance: program design for vernal pool policy innovation
Effective natural resource policy depends on knowing what is needed to sustain a resource and building the capacity to identify, develop, and implement flexible policies. This retrospective case study applies resilience concepts to a 16-year citizen science program and vernal pool regulatory development process in Maine, USA. We describe how citizen science improved adaptive capacities for innovative and effective policies to regulate vernal pools. We identified two core program elements that allowed people to act within narrow windows of opportunity for policy transformation, including (1) the simultaneous generation of useful, credible scientific knowledge and construction of networks among diverse institutions, and (2) the formation of diverse leadership that promoted individual and collective abilities to identify problems and propose policy solutions. If citizen science program leaders want to promote social-ecological systems resilience and natural resource policies as outcomes, we recommend they create a system for internal project evaluation, publish scientific studies using citizen science data, pursue resources for program sustainability, and plan for leadership diversity and informal networks to foster adaptive governance. Effective natural resource policy depends on knowing what is needed to sustain a resource and building the capacity to identify, develop, and implement flexible policies. This retrospective case study applies resilience concepts to a 16-year citizen science program and vernal pool regulatory development process in Maine, USA. We describe how citizen science improved adaptive capacities for innovative and effective policies to regulate vernal pools. We identified two core program elements that allowed people to act within narrow windows of opportunity for policy transformation, including (1) the simultaneous generation of useful, credible scientific knowledge and construction of networks among diverse institutions, and (2) the formation of diverse leadership that promoted individual and collective abilities to identify problems and propose policy solutions. If citizen science program leaders want to promote social-ecological systems resilience and natural resource policies as outcomes, we recommend they create a system for internal project evaluation, publish scientific studies using citizen science data, pursue resources for program sustainability, and plan for leadership diversity and informal networks to foster adaptive governance
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Aberrant activity in conceptual networks underlies N400 deficits and unusual thoughts in schizophrenia.
BackgroundThe N400 event-related potential (ERP) is triggered by meaningful stimuli that are incongruous, or unmatched, with their semantic context. Functional magnetic resonance imaging (fMRI) studies have identified brain regions activated by semantic incongruity, but their precise links to the N400 ERP are unclear. In schizophrenia (SZ), N400 amplitude reduction is thought to reflect overly broad associations in semantic networks, but the abnormalities in brain networks underlying deficient N400 remain unknown. We utilized joint independent component analysis (JICA) to link temporal patterns in ERPs to neuroanatomical patterns from fMRI and investigate relationships between N400 amplitude and neuroanatomical activation in SZ patients and healthy controls (HC).MethodsSZ patients (n = 24) and HC participants (n = 25) performed a picture-word matching task, in which words were either matched (APPLE→apple) by preceding pictures, or were unmatched by semantically related (in-category; IC, APPLE→lemon) or unrelated (out of category; OC, APPLE→cow) pictures, in separate ERP and fMRI sessions. A JICA "data fusion" analysis was conducted to identify the fMRI brain regions specifically associated with the ERP N400 component. SZ and HC loading weights were compared and correlations with clinical symptoms were assessed.ResultsJICA identified an ERP-fMRI "fused" component that captured the N400, with loading weights that were reduced in SZ. The JICA map for the IC condition showed peaks of activation in the cingulate, precuneus, bilateral temporal poles and cerebellum, whereas the JICA map from the OC condition was linked primarily to visual cortical activation and the left temporal pole. Among SZ patients, fMRI activity from the IC condition was inversely correlated with unusual thought content.ConclusionsThe neural networks associated with the N400 ERP response to semantic violations depends on conceptual relatedness. These findings are consistent with a distributed network underlying neural responses to semantic incongruity including unimodal visual areas as well as integrative, transmodal areas. Unusual thoughts in SZ may reflect impaired processing in transmodal hub regions such as the precuneus, leading to overly broad semantic associations
Deep Chronnectome Learning via Full Bidirectional Long Short-Term Memory Networks for MCI Diagnosis
Brain functional connectivity (FC) extracted from resting-state fMRI
(RS-fMRI) has become a popular approach for disease diagnosis, where
discriminating subjects with mild cognitive impairment (MCI) from normal
controls (NC) is still one of the most challenging problems. Dynamic functional
connectivity (dFC), consisting of time-varying spatiotemporal dynamics, may
characterize "chronnectome" diagnostic information for improving MCI
classification. However, most of the current dFC studies are based on detecting
discrete major brain status via spatial clustering, which ignores rich
spatiotemporal dynamics contained in such chronnectome. We propose Deep
Chronnectome Learning for exhaustively mining the comprehensive information,
especially the hidden higher-level features, i.e., the dFC time series that may
add critical diagnostic power for MCI classification. To this end, we devise a
new Fully-connected Bidirectional Long Short-Term Memory Network (Full-BiLSTM)
to effectively learn the periodic brain status changes using both past and
future information for each brief time segment and then fuse them to form the
final output. We have applied our method to a rigorously built large-scale
multi-site database (i.e., with 164 data from NCs and 330 from MCIs, which can
be further augmented by 25 folds). Our method outperforms other
state-of-the-art approaches with an accuracy of 73.6% under solid
cross-validations. We also made extensive comparisons among multiple variants
of LSTM models. The results suggest high feasibility of our method with
promising value also for other brain disorder diagnoses.Comment: The paper has been accepted by MICCAI201
Some Investigation of the Ethanol Carbontetrachloride System
The Ethanol Carbontetrachloride system has been investigated with respect to the total vapor pressure, and the partial vapor pressures of the constituents at twenty-five and sixty degrees. The total pressures of different mixtures of Ethanol Carbontetrachloride were determined at twenty-five degrees by means of a bulb to which was sealed a manometer. The total pressure at sixty degrees was measured by means of an apparatus designed by the authors for the rapid and accurate determination of the vapor pressures of liquids that do not readily react with mercury. A description of this apparatus will appear in the Journal of Industrial and Engineering Chemistry. The Partial pressures were determined from the molfraction of each constituent in the vapor. The molfractions of each constituent in the vapor were determined by condensing a small amount of vapor and determining its density. Curves were plotted for each temperature representing the total and partial pressures
Improving Performance of Iterative Methods by Lossy Checkponting
Iterative methods are commonly used approaches to solve large, sparse linear
systems, which are fundamental operations for many modern scientific
simulations. When the large-scale iterative methods are running with a large
number of ranks in parallel, they have to checkpoint the dynamic variables
periodically in case of unavoidable fail-stop errors, requiring fast I/O
systems and large storage space. To this end, significantly reducing the
checkpointing overhead is critical to improving the overall performance of
iterative methods. Our contribution is fourfold. (1) We propose a novel lossy
checkpointing scheme that can significantly improve the checkpointing
performance of iterative methods by leveraging lossy compressors. (2) We
formulate a lossy checkpointing performance model and derive theoretically an
upper bound for the extra number of iterations caused by the distortion of data
in lossy checkpoints, in order to guarantee the performance improvement under
the lossy checkpointing scheme. (3) We analyze the impact of lossy
checkpointing (i.e., extra number of iterations caused by lossy checkpointing
files) for multiple types of iterative methods. (4)We evaluate the lossy
checkpointing scheme with optimal checkpointing intervals on a high-performance
computing environment with 2,048 cores, using a well-known scientific
computation package PETSc and a state-of-the-art checkpoint/restart toolkit.
Experiments show that our optimized lossy checkpointing scheme can
significantly reduce the fault tolerance overhead for iterative methods by
23%~70% compared with traditional checkpointing and 20%~58% compared with
lossless-compressed checkpointing, in the presence of system failures.Comment: 14 pages, 10 figures, HPDC'1
Community-based Strategies for Strengthening Science and Influencing Policy: Vernal Pool Initiatives in Maine
Scientific research is not having the impact it could and should have on natural resources conservation. Rather than conceptualize and conduct research in isolation, we need new approaches to identify and investigate problems in coordination with stakeholders, poliÂcymakers, and others who would benefit from the research. By supporting partnerships between researchers and the public, citizen science creates new opportunities for stakeÂholders to interact with scientific experts. This process of public collaboration with scienÂtists has far-reaching implications for science, management, and policy. Drawing on two decades of work on vernal pool management strategies in Maine, we illustrate how citiÂzen science and engaged research helped bridge the science-policy gap. As scientists, we learned from diverse stakeholders at multiple levels of decision making, and this feedback led to improvements in our citizen science programs, gradual adaptations to our scientific research process, and locally based, innovative vernal pool policy initiatives
Reaching urban female adolescents at key points of sexual and reproductive health transitions: evidence from a longitudinal study from Kenya
Urban areas include large numbers of adolescents (ages 15-19) and young adults (ages 20-24) who may have unmet sexual and reproductive health (SRH) needs. Worldwide, adolescents contribute 11% of births, many of which are in low and middle-income countries. This study uses recently collected longitudinal data from urban Kenyan women to examine the association between targeted intervention activities and adolescents‘ SRH transitions. The focus was on a female adolescent (15-19) sample and their transition to first sex and first pregnancy/birth. Multinomial logistic regression methods were used to examine whether exposure to program activities was associated with delays in transitions. Overall, a high percentage of adolescents were exposed to television activities with family planning messages. About a third were exposed to community events, program posters, or the Shujaaz comic book that included themes related to relationships and positive health outcomes using recognizable characters. Multivariate analyses found that exposure to the Shujaaz comic book was associated with remaining sexually inexperienced and never pregnant at end line. Future programs for urban adolescents should implement interventions that test novel media strategies, like the Shujaaz comic book, that may be more interesting for young people. Innovative strategies are needed to reach female adolescents in urban settings.Keywords: Urban; Kenya; Sexual Initiation; Pregnancy; Adolescent
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