800 research outputs found
Jet Observables Without Jet Algorithms
We introduce a new class of event shapes to characterize the jet-like
structure of an event. Like traditional event shapes, our observables are
infrared/collinear safe and involve a sum over all hadrons in an event, but
like a jet clustering algorithm, they incorporate a jet radius parameter and a
transverse momentum cut. Three of the ubiquitous jet-based observables---jet
multiplicity, summed scalar transverse momentum, and missing transverse
momentum---have event shape counterparts that are closely correlated with their
jet-based cousins. Due to their "local" computational structure, these jet-like
event shapes could potentially be used for trigger-level event selection at the
LHC. Intriguingly, the jet multiplicity event shape typically takes on
non-integer values, highlighting the inherent ambiguity in defining jets. By
inverting jet multiplicity, we show how to characterize the transverse momentum
of the n-th hardest jet without actually finding the constituents of that jet.
Since many physics applications do require knowledge about the jet
constituents, we also build a hybrid event shape that incorporates (local) jet
clustering information. As a straightforward application of our general
technique, we derive an event-shape version of jet trimming, allowing
event-wide jet grooming without explicit jet identification. Finally, we
briefly mention possible applications of our method for jet substructure
studies.Comment: v2 - 31 pages, 18 figures; update to JHEP version, section 3.2
expanded, reference to FastJet contrib updated, results unchange
AUMI-Futurism: the Elsewhere and "Elsewhen" of (Un)Rolling the Boulder and Turning the Page
This article discusses two performances that used the movement-to-music technology known as the "Adaptive Use Musical Instrument" or AUMI to allow differently-abled participants to collaborate with one another: (Un)Rolling the Boulder: Improvising New Communities, a multimedia, mixed-ability improvisation that was staged at the University of Kansas in October 2013 and Turning the Page, an interdisciplinary musical theatre piece premiered in Ottawa, Canada in April 2014. We theorize these performances as examples of "AUMI-Futurism”, combining insights gleaned from two different sources: the Afrofuturist philosophy of composer, improviser, and bandleader Sun Ra, and the work of disability studies scholar Alison Kafer. This essay examines the collaborative, improvisatory processes that surrounded (Un)Rolling the Boulder and Turning the Page, focusing in particular on the role that the AUMI software played in imagining and performing new communities
Light transient behavior of mercury arc discharges
Call number: LD2668 .T4 1957 T82Master of Scienc
Finalist essays from the Center for Homeland Defense and Security's First Annual Essay Competition, 2008
The Center for Homeland Defense and Security (CHDS) announces the winner and finalists
of its first annual essay contest. CHDS launched the contest last year to provide people from
around the country the opportunity to express their opinions on homeland security issues
and to suggest new ideas. The winner and four finalists were selected from eighty contest
submissions by a committee comprised of CHDS staff, faculty, and alumni. The variety of
the essay topics submitted, as well as the backgrounds of the authors, highlights the vast
scope of the impact that homeland security policies, programs, and challenges have on our
communities and professions. This year’s contestants were asked to answer the question
“What single aspect of Homeland Security has been most successful, and what single aspect
will be most critical to Homeland Security success?”Naval Posgraduate School, Center for Homeland Defense and Securit
Müller cell activation, proliferation and migration following laser injury.
PurposeMüller cells are well known for their critical role in normal retinal structure and function, but their reaction to retinal injury and subsequent role in retinal remodeling is less well characterized. In this study we used a mouse model of retinal laser photocoagulation to examine injury-induced Müller glial reaction, and determine how this reaction was related to injury-induced retinal regeneration and cellular repopulation.MethodsExperiments were performed on 3-4-week-old C57BL/6 mice. Retinal laser photocoagulation was used to induce small, circumscribed injuries; these were principally confined to the outer nuclear layer, and surrounded by apparently healthy retinal tissue. Western blotting and immunohistochemical analyses were used to determine the level and location of protein expression. Live cell imaging of green fluorescent protein (GFP)-infected Müller cells (AAV-GFAP-GFP) were used to identify the rate and location of retinal Müller cell nuclear migration.ResultsUpon injury, Müller cells directly at the burn site become reactive, as evidenced by increased expression of the intermediate filament proteins glial fibrillary acidic protein (GFAP) and nestin. These reactive cells re-enter the cell cycle as shown by expression of the markers Cyclin D1 and D3, and their nuclei begin to migrate toward the injury site at a rate of approximately 12 microm/hr. However, unlike other reports, evidence for Müller cell transdifferentiation was not identified in this model.ConclusionsRetinal laser photocoagulation is capable of stimulating a significant glial reaction, marked by activation of cell cycle progression and retinal reorganization, but is not capable of stimulating cellular transdifferentiation or neurogenesis
The Inq13 POOC::A Participatory Experiment in Open, Collaborative Teaching and Learning.
This article offers a broad analysis of a POOC (“Participatory Open Online Course”) offered through the Graduate Center, CUNY in 2013. The large collaborative team of instructors, librarians, educational technologists, videographers, students, and project leaders reflects on the goals, aims, successes, and challenges of the experimental learning project. The graduate course, which sought to explore issues of participatory research, inequality and engaged uses of digital technology with and through the New York City neighborhood of East Harlem, set forth a unique model of connected learning that stands in contrast to the popular MOOC (Massive Open Online Course) model
Idiopathic multifocal choroiditis/punctate inner choroidopathy with acute photoreceptor loss or dysfunction out of proportion to clinically visible lesions.
PURPOSE
To report acute/subacute vision loss and paracentral scotomata in patients with idiopathic multifocal choroiditis/punctate inner choroidopathy due to large zones of acute photoreceptor attenuation surrounding the chorioretinal lesions.
METHODS
Multimodal imaging case series.
RESULTS
Six women and 2 men were included (mean age, 31.5 ± 5.8 years). Vision ranged from 20/20-1 to hand motion (mean, 20/364). Spectral domain optical coherence tomography demonstrated extensive attenuation of the external limiting membrane, ellipsoid and interdigitation zones, adjacent to the visible multifocal choroiditis/punctate inner choroidopathy lesions. The corresponding areas were hyperautofluorescent on fundus autofluorescence and were associated with corresponding visual field defects. Full-field electroretinogram (available in three cases) showed markedly decreased cone/rod response, and multifocal electroretinogram revealed reduced amplitudes and increased implicit times in two cases. Three patients received no treatment, the remaining were treated with oral corticosteroids (n = 4), oral acyclovir/valacyclovir (n = 2), intravitreal/posterior subtenon triamcinolone acetate (n = 3), and anti-vascular endothelial growth factor (n = 2). Visual recovery occurred in only three cases of whom two were treated. Varying morphological recovery was found in six cases, associated with decrease in hyperautofluorescence on fundus autofluorescence.
CONCLUSION
Multifocal choroiditis/punctate inner choroidopathy can present with transient or permanent central photoreceptor attenuation/loss. This presentation is likely a variant of multifocal choroiditis/punctate inner choroidopathy with chorioretinal atrophy. Associated changes are best evaluated using multimodal imaging
The Atacama Cosmology Telescope: Two-Season ACTPol Spectra and Parameters
We present the temperature and polarization angular power spectra measured by
the Atacama Cosmology Telescope Polarimeter (ACTPol). We analyze night-time
data collected during 2013-14 using two detector arrays at 149 GHz, from 548
deg of sky on the celestial equator. We use these spectra, and the spectra
measured with the MBAC camera on ACT from 2008-10, in combination with Planck
and WMAP data to estimate cosmological parameters from the temperature,
polarization, and temperature-polarization cross-correlations. We find the new
ACTPol data to be consistent with the LCDM model. The ACTPol
temperature-polarization cross-spectrum now provides stronger constraints on
multiple parameters than the ACTPol temperature spectrum, including the baryon
density, the acoustic peak angular scale, and the derived Hubble constant.
Adding the new data to planck temperature data tightens the limits on damping
tail parameters, for example reducing the joint uncertainty on the number of
neutrino species and the primordial helium fraction by 20%.Comment: 23 pages, 25 figure
Age-related delay in information accrual for faces: Evidence from a parametric, single-trial EEG approach
Background: In this study, we quantified age-related changes in the time-course of face processing
by means of an innovative single-trial ERP approach. Unlike analyses used in previous studies, our
approach does not rely on peak measurements and can provide a more sensitive measure of
processing delays. Young and old adults (mean ages 22 and 70 years) performed a non-speeded
discrimination task between two faces. The phase spectrum of these faces was manipulated
parametrically to create pictures that ranged between pure noise (0% phase information) and the
undistorted signal (100% phase information), with five intermediate steps.
Results: Behavioural 75% correct thresholds were on average lower, and maximum accuracy was
higher, in younger than older observers. ERPs from each subject were entered into a single-trial
general linear regression model to identify variations in neural activity statistically associated with
changes in image structure. The earliest age-related ERP differences occurred in the time window
of the N170. Older observers had a significantly stronger N170 in response to noise, but this age
difference decreased with increasing phase information. Overall, manipulating image phase
information had a greater effect on ERPs from younger observers, which was quantified using a
hierarchical modelling approach. Importantly, visual activity was modulated by the same stimulus
parameters in younger and older subjects. The fit of the model, indexed by R2, was computed at
multiple post-stimulus time points. The time-course of the R2 function showed a significantly slower
processing in older observers starting around 120 ms after stimulus onset. This age-related delay
increased over time to reach a maximum around 190 ms, at which latency younger observers had
around 50 ms time lead over older observers.
Conclusion: Using a component-free ERP analysis that provides a precise timing of the visual
system sensitivity to image structure, the current study demonstrates that older observers
accumulate face information more slowly than younger subjects. Additionally, the N170 appears to
be less face-sensitive in older observers
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