3,560 research outputs found
In vivo characterization of hippocampal electrophysiological processes in the heterozygous Pten knockout model of autism
While cognitive deficits have been described in the heterozygous Pten (+/-) KO mouse model of autism, little work has been done to demonstrate how corresponding in vitro physiological alterations in this model may underpin these cognitive deficits in vivo. As Pten KO (+/-) is known to alter electrophysiological characteristics of neurons in vitro, this study measures the in vivo electrophysiological characteristics of CA1 interneurons, pyramidal cells, and place cells which may underlie the spatial cognitive deficits seen in the model. Four transgenic conditional heterozygous Pten+/loxPloxP;Gfap-cre mice (HetPten) and four homozygous Pten littermate control mice were used in this study. This transgene drives cre expression and excision of the Pten gene in hippocampal granule cells of the dentate gyrus, and neurons in CA2 and CA1, but not astrocytes. In vivo local field potentials and single cell recordings were made in CA1 of each mouse during an open field foraging task in two distinct arenas. HetPten mice were found to have increased interneuron and pyramidal cell firing rates. In addition, place cells demonstrated abnormal properties including increased out-of-field firing rates, an increased number of fields, and trends towards larger field sizes that were less stable in comparison to controls. HetPten mice had slower CA1 fast gamma oscillations and more variable speed/theta oscillation correlations. Behaviorally, there were weak trends towards decreased motor output compared to controls. These data suggest that the electrophysiological alterations due to Pten KO (+/-) in mouse hippocampal neurons lead to hyperactivation of CA1 interneurons, pyramidal cells, and place cells
A Quantitative Approach to Understanding Online Antisemitism
A new wave of growing antisemitism, driven by fringe Web communities, is an
increasingly worrying presence in the socio-political realm. The ubiquitous and
global nature of the Web has provided tools used by these groups to spread
their ideology to the rest of the Internet. Although the study of antisemitism
and hate is not new, the scale and rate of change of online data has impacted
the efficacy of traditional approaches to measure and understand these
troubling trends. In this paper, we present a large-scale, quantitative study
of online antisemitism. We collect hundreds of million posts and images from
alt-right Web communities like 4chan's Politically Incorrect board (/pol/) and
Gab. Using scientifically grounded methods, we quantify the escalation and
spread of antisemitic memes and rhetoric across the Web. We find the frequency
of antisemitic content greatly increases (in some cases more than doubling)
after major political events such as the 2016 US Presidential Election and the
"Unite the Right" rally in Charlottesville. We extract semantic embeddings from
our corpus of posts and demonstrate how automated techniques can discover and
categorize the use of antisemitic terminology. We additionally examine the
prevalence and spread of the antisemitic "Happy Merchant" meme, and in
particular how these fringe communities influence its propagation to more
mainstream communities like Twitter and Reddit. Taken together, our results
provide a data-driven, quantitative framework for understanding online
antisemitism. Our methods serve as a framework to augment current qualitative
efforts by anti-hate groups, providing new insights into the growth and spread
of hate online.Comment: To appear at the 14th International AAAI Conference on Web and Social
Media (ICWSM 2020). Please cite accordingl
Axonal Activity In Vivo: Technical Considerations and Implications for the Exploration of Neural Circuits in Freely Moving Animals
While extracellular somatic action potentials from freely moving rats have been well characterized, axonal activity has not. We have recently reported extracellular tetrode recordings of short duration waveforms (SDWs) with an average peak-trough duration less than 172μs. These waveforms have significantly shorter duration than somatic action potentials and tend to be triphasic. The present review discusses further data that suggests SDWs are representative of axonal activity, how this characterization allows for more accurate classification of somatic activity and could serve as a means of exploring signal integration in neural circuits. The review also discusses how axons may function as more than neural cables and the implications this may have for axonal information processing. While the technical challenges necessary for the exploration of axonal processes in functional neural circuits during behavior are impressive, preliminary evidence suggests that the in vivo study of axons is attainable. The resulting theoretical implications for systems level function make refinement of this approach a necessary goal toward developing a more complete understanding of the processes underlying learning, memory and attention as well as the pathological states underlying mental illness and epilepsy
Colonising the Field ) Who,s Playing with Web-based Information Systems Development?
domain of systems and software development, in both practice and research. Surprisingly, while there would appear to be many common activities, the academic fields have traditionally had limited overlap or shared experience. The information systems school has largely focused on in-house systems, concentrating on the socio-technical approach toward systems development while software engineering attempts to apply engineering principles and formal methods to the production of software systems. However the fields collide where new, Web-based systems share both in-house usage and external commercial software characteristics. While it might be expected that practitioners would be informed by innovative development methods, research indicates that practitioners are not making use of new multimedia and web development method and techniques. The crossover between the fields of IS and SE resurrects up some old problems and new questions. This paper traces the roots of IS and SE; briefly contrasts education and research of each; and examines the differences and common areas of the fields. From a study of how each field is characterised an IS body of knowledge (ISBOK) is identified. How Web-based Information Systems relate to each field is discussed and from the analysis a simple classification framework is constructed, weighing a systems life cycle against quality. The paper concludes with a call for greater cross-fertilization between the fields. Finally the authors suggest important subjects that IS researchers should be studying and others that should be of interest to both SE and IS researchers
Finding a Home for Web Based Information Systems - Perusing the Landscape
Information systems (IS) and software engineering (SE) have shared the domain of systems and software development for several decades with too little overlap in practice and research. The IS school has largely focused on in-house systems, concentrating on the human-computer aspects of systems development while SE attempts to apply engineering principles and methods to the production of software systems. However the fields collide where new, Web-based systems share both in-house usage and external commercial software characteristics. In this paper, the origins and the development of education of both fields are explored – then various aspects are compared and contrasted. If, as it would appear, recommended development methods are ineffective or simply not being used, is a new understanding of development practice that finds expression in creativity and improvisation the way forward, or is this just a new engineering problem to be solved? The authors conclude that we need fast and flexible methods that go beyond new SE techniques for the Web, reflecting the business imperative to quickly produce high-quality robust systems in competitive environments. Web-based systems development should be contextualized within IS theory - learning from the rigour of SE - but viewed definitively as part of a larger socio-technical system
Adolescent Leadership Skill Development Through Residential 4-H Camp Counseling
Camping is a 4-H delivery mode and context for positive youth development. Research suggests that 4-H camping may enhance the life skills outcomes of adolescents who serve in leadership roles. The study reported here was to explore the lived experience of 4-H camp teen counselors and to better understand the leadership and life skill outcomes of 4-H camp participation. Eleven focus groups (n=68) were conducted with 4-H camp teen counselors from across Virginia\u27s six 4-H educational centers. The results indicated that 4-H camp participation positively affected teen counselors by helping them to develop leadership-related knowledge, skills, and behaviors
Applying DDI to a Longitudinal Study of Aging
Presentation at the North American Data Documentation Conference (NADDI) 2013Midlife in the United States (MIDUS) is a large, multi-disciplinary longitudinal study of aging conducted by the University of Wisconsin. MIDUS researchers want to provide a comprehensive, canonical source of documentation for the research project. To accomplish this, the team took the diverse set of sources that previously documented the MIDUS study and created a standardized, DDI 3-based set of documentation that better enables researchers to discover and use the MIDUS data. This talk will outline the process used to create the DDI 3 documentation, and will demonstrate the resulting documentation and dissemination tools provided by Colectica. The project is a joint effort between MIDUS and Colectica.Institute for Policy & Social Research, University of Kansas; University of Kansas Libraries; Alfred P. Sloan Foundation; Data Documentation Initiative Allianc
Generalized Integrated Brownian Fields for Simulation Metamodeling
We introduce a novel class of Gaussian random fields (GRFs), called generalized integrated Brownian fields (GIBFs), focusing on the use of GIBFs for Gaussian process regression in deterministic and stochastic simulation metamodeling. We build GIBFs from the well-known Brownian motion and discuss several of their properties, including differentiability that cart differ in each coordinate, no mean reversion, and the Markov property. We explain why we desire to use GRFs with these properties and provide formal definitions of mean reversion and the Markov property for real-valued, differentiable random fields. We show how to use GIBFs with stochastic kriging, covering trend modeling and parameter fitting, discuss their approximation capability, and show that the resulting metamodel also has differentiability that can differ in each coordinate. Last, we use several examples to demonstrate superior prediction capability as compared with the GRFs corresponding to the Gaussian and Matern covariance functions
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