195 research outputs found
Somatosensory Deficits in Post-ACL Reconstruction Patients: A Case-Control Study
Introduction: Diminished cutaneous detection thresholds have been identified in patients with multiple orthopedic conditions, and these phenomena may occur in postanterior cruciate ligament reconstructed (ACLR) patients. The purpose of this study was to determine if differences in lower extremity cutaneous detection thresholds exist in post-ACLR patients when compared with healthy controls. Methods: Fifteen individuals who were post-ACLR and 15 individuals who had no history of knee injury participated. Light touch cutaneous detection thresholds were assessed at 4 locations on the foot and ankle (first metatarsal, fifth metatarsal, medial malleolus, and lateral malleolus). Nonparametric statistics examined group differences between the sites. Results: ACLR subjects had decreased cutaneous sensation at the first metatarsal and medial malleolus compared with healthy controls. Conclusions: Somatosensory deficits are present in post-ACLR patients. Future research should investigate these phenomena longitudinally in post-ACLR individuals along with somatosensory targeted interventions
Finding Collisions in Interactive Protocols -- A Tight Lower Bound on the Round Complexity of Statistically-Hiding Commitments
We study the round complexity of various cryptographic protocols. Our main result is a tight lower bound on the round complexity of any fully-black-box construction of a statistically-hiding commitment scheme from one-way permutations, and even from trapdoor permutations. This lower bound matches the round complexity of the statistically-hiding commitment scheme due to Naor, Ostrovsky, Venkatesan and Yung (CRYPTO \u2792). As a corollary, we derive similar tight lower bounds for several other cryptographic protocols, such as single-server private information retrieval, interactive hashing, and oblivious transfer that guarantees statistical security for one of the parties.
Our techniques extend the collision-finding oracle due to Simon (EUROCRYPT \u2798) to the setting of interactive protocols (our extension also implies an alternative proof for the main property of the original oracle). In addition, we substantially extend the reconstruction paradigm of Gennaro and Trevisan (FOCS \u2700). In both cases, our extensions are quite delicate and may be found useful in proving additional black-box separation results
Combinatorics on words in information security: Unavoidable regularities in the construction of multicollision attacks on iterated hash functions
Classically in combinatorics on words one studies unavoidable regularities
that appear in sufficiently long strings of symbols over a fixed size alphabet.
In this paper we take another viewpoint and focus on combinatorial properties
of long words in which the number of occurrences of any symbol is restritced by
a fixed constant. We then demonstrate the connection of these properties to
constructing multicollision attacks on so called generalized iterated hash
functions.Comment: In Proceedings WORDS 2011, arXiv:1108.341
AVPR1a and SLC6A4 Gene Polymorphisms Are Associated with Creative Dance Performance
Dancing, which is integrally related to music, likely has its origins close to the birth of Homo sapiens, and throughout our history, dancing has been universally practiced in all societies. We hypothesized that there are differences among individuals in aptitude, propensity, and need for dancing that may partially be based on differences in common genetic polymorphisms. Identifying such differences may lead to an understanding of the neurobiological basis of one of mankind's most universal and appealing behavioral traits—dancing. In the current study, 85 current performing dancers and their parents were genotyped for the serotonin transporter (SLC6A4: promoter region HTTLPR and intron 2 VNTR) and the arginine vasopressin receptor 1a (AVPR1a: promoter microsatellites RS1 and RS3). We also genotyped 91 competitive athletes and a group of nondancers/nonathletes (n = 872 subjects from 414 families). Dancers scored higher on the Tellegen Absorption Scale, a questionnaire that correlates positively with spirituality and altered states of consciousness, as well as the Reward Dependence factor in Cloninger's Tridimensional Personality Questionnaire, a measure of need for social contact and openness to communication. Highly significant differences in AVPR1a haplotype frequencies (RS1 and RS3), especially when conditional on both SLC6A4 polymorphisms (HTTLPR and VNTR), were observed between dancers and athletes using the UNPHASED program package (Cocaphase: likelihood ratio test [LRS] = 89.23, p = 0.000044). Similar results were obtained when dancers were compared to nondancers/nonathletes (Cocaphase: LRS = 92.76, p = 0.000024). These results were confirmed using a robust family-based test (Tdtphase: LRS = 46.64, p = 0.010). Association was also observed between Tellegen Absorption Scale scores and AVPR1a (Qtdtphase: global chi-square = 26.53, p = 0.047), SLC6A4 haplotypes (Qtdtphase: chi-square = 2.363, p = 0.018), and AVPR1a conditional on SCL6A4 (Tdtphase: LRS = 250.44, p = 0.011). Similarly, significant association was observed between Tridimensional Personality Questionnaire Reward Dependence scores and AVPR1a RS1 (chi-square = 20.16, p = 0.01). Two-locus analysis (RS1 and RS3 conditional on HTTLPR and VNTR) was highly significant (LRS = 162.95, p = 0.001). Promoter repeat regions in the AVPR1a gene have been robustly demonstrated to play a role in molding a range of social behaviors in many vertebrates and, more recently, in humans. Additionally, serotonergic neurotransmission in some human studies appears to mediate human religious and spiritual experiences. We therefore hypothesize that the association between AVPR1a and SLC6A4 reflects the social communication, courtship, and spiritual facets of the dancing phenotype rather than other aspects of this complex phenotype, such as sensorimotor integration
Why Are Regulations Changed? A Parcel Analysis of Upzoning in Los Angeles
Planners, officials, and neighborhood groups often debate zoning changes, yet there is little empirical evidence explaining why zoning and other land use regulations are changed. I use logistic regression models to examine density-enabling rezoning (“upzoning”) in Los Angeles. I find that upzoning occurs where there are development opportunities combined with limited political resistance. Upzoning is most likely on well-located parcels zoned for low-intensity, nonresidential uses. Meanwhile, homeowners—and particularly homeowners with access to valuable amenities—are associated with regulatory stasis. I conclude by recommending strategies for addressing homeowners’ concerns about higher density housing
Evaluation in Nonhuman Primates of Vaccines against Ebola Virus
Ebola virus (EBOV) causes acute hemorrhagic fever that is fatal in up to 90% of cases in both humans and nonhuman primates. No vaccines or treatments are available for human use. We evaluated the effects in nonhuman primates of vaccine strategies that had protected mice or guinea pigs from lethal EBOV infection. The following immunogens were used: RNA replicon particles derived from an attenuated strain of Venezuelan equine encephalitis virus (VEEV) expressing EBOV glycoprotein and nucleoprotein; recombinant Vaccinia virus expressing EBOV glycoprotein; liposomes containing lipid A and inactivated EBOV; and a concentrated, inactivated whole-virion preparation. None of these strategies successfully protected nonhuman primates from robust challenge with EBOV. The disease observed in primates differed from that in rodents, suggesting that rodent models of EBOV may not predict the efficacy of candidate vaccines in primates and that protection of primates may require different mechanisms
Representations of sport in the revolutionary socialist press in Britain, 1988–2012
This paper considers how sport presents a dualism to those on the far left of the political spectrum. A long-standing, passionate debate has existed on the contradictory role played by sport, polarised between those who reject it as a bourgeois capitalist plague and those who argue for its reclamation and reformation. A case study is offered of a political party that has consistently used revolutionary Marxism as the basis for its activity and how this party, the largest in Britain, addresses sport in its publications. The study draws on empirical data to illustrate this debate by reporting findings from three socialist publications. When sport did feature it was often in relation to high profile sporting events with a critical tone adopted and typically focused on issues of commodification, exploitation and alienation of athletes and supporters. However, readers’ letters, printed in the same publications, revealed how this interpretation was not universally accepted, thus illustrating the contradictory nature of sport for those on the far left
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b
We present the highest fidelity spectrum to date of a planetary-mass object.
VHS 1256 b is a 20 M widely separated (8\arcsec, a =
150 au), young, planetary-mass companion that shares photometric colors and
spectroscopic features with the directly imaged exoplanets HR 8799 c, d, and e.
As an L-to-T transition object, VHS 1256 b exists along the region of the
color-magnitude diagram where substellar atmospheres transition from cloudy to
clear. We observed VHS 1256~b with \textit{JWST}'s NIRSpec IFU and MIRI MRS
modes for coverage from 1 m to 20 m at resolutions of 1,000 -
3,700. Water, methane, carbon monoxide, carbon dioxide, sodium, and potassium
are observed in several portions of the \textit{JWST} spectrum based on
comparisons from template brown dwarf spectra, molecular opacities, and
atmospheric models. The spectral shape of VHS 1256 b is influenced by
disequilibrium chemistry and clouds. We directly detect silicate clouds, the
first such detection reported for a planetary-mass companion.Comment: Accepted ApJL Iterations of spectra reduced by the ERS team are
hosted at this link:
https://github.com/bemiles/JWST_VHS1256b_Reduction/tree/main/reduced_spectr
The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems IV: NIRISS Aperture Masking Interferometry Performance and Lessons Learned
We present a performance analysis for the aperture masking interferometry
(AMI) mode on board the James Webb Space Telescope Near Infrared Imager and
Slitless Spectrograph (JWST/NIRISS). Thanks to self-calibrating observables,
AMI accesses inner working angles down to and even within the classical
diffraction limit. The scientific potential of this mode has recently been
demonstrated by the Early Release Science (ERS) 1386 program with a deep search
for close-in companions in the HIP 65426 exoplanetary system. As part of ERS
1386, we use the same dataset to explore the random, static, and calibration
errors of NIRISS AMI observables. We compare the observed noise properties and
achievable contrast to theoretical predictions. We explore possible sources of
calibration errors, and show that differences in charge migration between the
observations of HIP 65426 and point-spread function calibration stars can
account for the achieved contrast curves. Lastly, we use self-calibration tests
to demonstrate that with adequate calibration, NIRISS AMI can reach contrast
levels of mag. These tests lead us to observation planning
recommendations and strongly motivate future studies aimed at producing
sophisticated calibration strategies taking these systematic effects into
account. This will unlock the unprecedented capabilities of JWST/NIRISS AMI,
with sensitivity to significantly colder, lower mass exoplanets than
ground-based setups at orbital separations inaccessible to JWST coronagraphy.Comment: 20 pages, 12 figures, submitted to AAS Journal
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