178 research outputs found
Supporting Youth in Transition to Adulthood: Lessons Learned from Child Welfare and Juvenile Justice
The Georgetown Public Policy Institute's Center for Juvenile Justice Reform and the Jim Casey Youth Opportunities Initiative collaborated to publish this paper that describes case assessment, case management, and other practices implemented in the juvenile justice and child welfare systems. The practices highlighted have shown promise in improving outcomes for the transition-age population
The Drinfel'd Double and Twisting in Stringy Orbifold Theory
This paper exposes the fundamental role that the Drinfel'd double \dkg of
the group ring of a finite group and its twists \dbkg, \beta \in
Z^3(G,\uk) as defined by Dijkgraaf--Pasquier--Roche play in stringy orbifold
theories and their twistings.
The results pertain to three different aspects of the theory. First, we show
that --Frobenius algebras arising in global orbifold cohomology or K-theory
are most naturally defined as elements in the braided category of
\dkg--modules. Secondly, we obtain a geometric realization of the Drinfel'd
double as the global orbifold --theory of global quotient given by the
inertia variety of a point with a action on the one hand and more
stunningly a geometric realization of its representation ring in the braided
category sense as the full --theory of the stack . Finally, we show
how one can use the co-cycles above to twist a) the global orbifold
--theory of the inertia of a global quotient and more importantly b) the
stacky --theory of a global quotient . This corresponds to twistings
with a special type of 2--gerbe.Comment: 35 pages, no figure
Interstitial Fractionalization and Spherical Crystallography
Finding the ground states of identical particles packed on spheres has
relevance for stabilizing emulsions and a venerable history in the literature
of theoretical physics and mathematics. Theory and experiment have confirmed
that defects such as disclinations and dislocations are an intrinsic part of
the ground state. Here we discuss the remarkable behavior of vacancies and
interstitials in spherical crystals. The strain fields of isolated
disclinations forced in by the spherical topology literally rip interstitials
and vacancies apart, typically into dislocation fragments that combine with the
disclinations to create small grain boundary scars. The fractionation is often
into three charge-neutral dislocations, although dislocation pairs can be
created as well. We use a powerful, freely available computer program to
explore interstitial fractionalization in some detail, for a variety of power
law pair potentials. We investigate the dependence on initial conditions and
the final state energies, and compare the position dependence of interstitial
energies with the predictions of continuum elastic theory on the sphere. The
theory predicts that, before fragmentation, interstitials are repelled from
5-fold disclinations and vacancies are attracted. We also use vacancies and
interstitials to study low energy states in the vicinity of "magic numbers"
that accommodate regular icosadeltahedral tessellations.Comment: 21 pages, 9 figure
Differential Liquidity Provision in Uniswap v3 and Implications for Contract Design
Decentralized exchanges (DEXs) provide a means for users to trade pairs of
assets on-chain without the need of a trusted third party to effectuate a
trade. Amongst these, constant function market maker (CFMM) DEXs such as
Uniswap handle the most volume of trades between ERC-20 tokens. With the
introduction of Uniswap v3, liquidity providers are given the option to
differentially allocate liquidity to be used for trades that occur within
specific price intervals. In this paper, we formalize the profit and loss that
liquidity providers can earn when providing specific liquidity positions to a
contract. With this in hand, we are able to compute optimal liquidity
allocations for liquidity providers who hold beliefs over how prices evolve
over time. Ultimately, we use this tool to shed light on the design question
regarding how v3 contracts should partition price space for permissible
liquidity allocations. Our results show that a richer space of potential
partitions can simultaneously benefit both liquidity providers and traders.Comment: 48 pages, 13 figure
An Evaluation of Otopathology in the MOV-13 Transgenic Mutant Mouse a
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72482/1/j.1749-6632.1991.tb19595.x.pd
Balance beam crossing times are slower after noise exposure in rats
IntroductionThe vestibular system integrates signals related to vision, head position, gravity, motion, and body position to provide stability during motion through the environment. Disruption in any of these systems can reduce agility and lead to changes in ability to safely navigate one’s environment. Causes of vestibular decline are diverse; however, excessive noise exposure can lead to otolith organ dysfunction. Specifically, 120 decibel (dB) sound pressure level (SPL) 1.5 kHz-centered 3-octave band noise (1.5 kHz 3OBN) causes peripheral vestibular dysfunction in rats, measured by vestibular short-latency evoked potential (VsEP) and reduced calretinin-immunolabeling of calyx-only afferent terminals in the striolar region of the saccule. The present study examined the functional impact of this noise exposure condition, examining changes in motor performance after noise exposure with a balance beam crossing task.MethodsBalance beam crossing time in rats was assessed for 19 weeks before and 5 weeks after noise exposure. Balance beam crossings were scored to assess proficiency in the task. When animals were proficient, they received a single exposure to 120 dB SPL 3-octave band noise.ResultsDuring the initial training phase slower crossing times and higher scores, including multiple failures were observed. This was followed by a period of significant improvement leading to proficiency, characterized by fast and stable crossing times and consistently low scores. After noise exposure, crossing times were significantly elevated from baseline for 4-weeks. A total of 5 weeks after noise exposure, crossing times improved, and though still trending higher than baseline, they were no longer significantly different from baseline.DiscussionThese findings show that the noise-induced peripheral vestibular changes we previously observed at cellular and electro-physiological levels also have an impact at a functional level. It has been previously shown that imbalance is associated with slower walking speed in older adults and aged rats. These findings in noise-exposed rats may have implications for people who experience noisy environments and for seniors with a history of noise exposure who also experience balance disorders and may be at increased fall risk
Higher spin AdS_3 supergravity and its dual CFT
Vasiliev's higher spin supergravity theory on three dimensional anti-de
Sitter space is studied and, in particular, the partition function is computed
at one loop level. The dual conformal field theory is proposed to be the
N=(2,2) CP^N Kazama-Suzuki model in two dimensions. The proposal is based on
symmetry considerations and comparison of the bulk partition function with the
conformal field theory. Our findings suggest that the theory is strong-weak
self-dual.Comment: 36 page
Parsec-Scale Blazar Monitoring: Flux and Polarization Variability
We present analysis of the flux and polarization variability of parsec scale
radio jets from a dual-frequency, six-epoch, VLBA polarization experiment
monitoring 12 blazars. The observations were made at 15 and 22 GHz at bimonthly
intervals over 1996. Here we analyze the flux, fractional polarization, and
polarization position angle behavior of core regions and jet features,
considering both the linear trends of these quantities with time and more rapid
fluctuations about the linear trends. The dual frequency nature of the
observations allows us to examine spectral evolution, to separate Faraday
effects from changes in magnetic field order, and also to deduce empirical
estimates for the uncertainties in measuring properties of VLBI jet features
(abridged).Comment: 35 pages, 30 figures, accepted by the Astrophysical Journal (Changes
from original version: typos corrected and a clarification in terminology
Apical hair cells and hearing
This study assessed the contribution of the apical hair cells to hearing. Guinea pigs, chinchillas and monkeys were behaviorally trained using positive reinforcement to respond to pure-tone stimuli. When a stable audiogram had been determined, each subject received one of three experimental treatments: ototoxic drug administration, low-frequency noise exposure, or the application of a cryoprobe to the bony wall of the cochlear apex. After post-treatment audiograms stabilized, subjects were euthanized and the percentage of hair cells remaining was assessed by light microscopy. Results indicate that a redundancy of encoding mechanisms exist in the mammalian cochlea for low-frequency stimuli. They also suggest that a very small percentage of apical hair cells are sufficient for some low-frequency hearing. Finally, data from this and other studies suggest that the low-frequency threshold shift caused by the loss of a certain percentage of apical hair cells is less pronounced than the high-frequency threshold shift caused by the loss of a comparable percentage of basal hair cells. These data agree with anatomical and electrophysiological evidence that functional as well as anatomical differences may exist between the apex and base of the cochlea.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28701/1/0000521.pd
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