588 research outputs found
A comparison of washout filters using a human dynamic orientation model
Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.Microfiche copy available in Archives and Barker.Bibliography: 142-145.by Susan A. Riedel.M.S
Design, engineering and utility of biotic games
Games are a significant and defining part of human culture, and their utility beyond pure entertainment has been demonstrated with so-called âserious gamesâ. Biotechnology â despite its recent advancements â has had no impact on gaming yet. Here we propose the concept of âbiotic gamesâ, i.e., games that operate on biological processes. Utilizing a variety of biological processes we designed and tested a collection of games: âEnlightenmentâ, âCiliaballâ, âPAC-meciumâ, âMicrobashâ, âBiotic Pinballâ, âPOND PONGâ, âPolymerRaceâ, and âThe Prisoner's Smellemmaâ. We found that biotic games exhibit unique features compared to existing game modalities, such as utilizing biological noise, providing a real-life experience rather than virtual reality, and integrating the chemical senses into play. Analogous to video games, biotic games could have significant conceptual and cost-reducing effects on biotechnology and eventually healthcare; enable volunteers to participate in crowd-sourcing to support medical research; and educate society at large to support personal medical decisions and the public discourse on bio-related issues
Relation of Parkinson\u27s Disease Subtypes to Visual Activities of Daily Living
Visual perceptual problems are common in Parkinson\u27s disease (PD) and often affect activities of daily living (ADLs). PD patients with non-tremor symptoms at disease onset (i.e., rigidity, bradykinesia, gait disturbance or postural instability) have more diffuse neurobiological abnormalities and report worse non-motor symptoms and functional changes than patients whose initial symptom is tremor, but the relation of motor symptom subtype to perceptual deficits remains unstudied. We assessed visual ADLs with the Visual Activities Questionnaire in 25 non-demented patients with PD, 13 with tremor as the initial symptom and 12 with an initial symptom other than tremor, as well as in 23 healthy control participants (NC). As expected, the non-tremor patients, but not the tremor patients, reported more impairment in visual ADLs than the NC group, including in light/dark adaptation, acuity/spatial vision, depth perception, peripheral vision and visual processing speed. Non-tremor patients were significantly worse than tremor patients overall and on light/dark adaptation and depth perception. Environmental enhancements especially targeted to patients with the non-tremor PD subtype may help to ameliorate their functional disability
Atom chip based generation of entanglement for quantum metrology
Atom chips provide a versatile `quantum laboratory on a microchip' for
experiments with ultracold atomic gases. They have been used in experiments on
diverse topics such as low-dimensional quantum gases, cavity quantum
electrodynamics, atom-surface interactions, and chip-based atomic clocks and
interferometers. A severe limitation of atom chips, however, is that techniques
to control atomic interactions and to generate entanglement have not been
experimentally available so far. Such techniques enable chip-based studies of
entangled many-body systems and are a key prerequisite for atom chip
applications in quantum simulations, quantum information processing, and
quantum metrology. Here we report experiments where we generate multi-particle
entanglement on an atom chip by controlling elastic collisional interactions
with a state-dependent potential. We employ this technique to generate
spin-squeezed states of a two-component Bose-Einstein condensate and show that
they are useful for quantum metrology. The observed 3.7 dB reduction in spin
noise combined with the spin coherence imply four-partite entanglement between
the condensate atoms and could be used to improve an interferometric
measurement by 2.5 dB over the standard quantum limit. Our data show good
agreement with a dynamical multi-mode simulation and allow us to reconstruct
the Wigner function of the spin-squeezed condensate. The techniques
demonstrated here could be directly applied in chip-based atomic clocks which
are currently being set up
Production of pions, kaons, and protons as a function of the relative transverse activity classifier in pp collisions at = 13 TeV
Abstract: The production of ϱ, K±, and ( p )p is measured in pp collisions at âs = 13 TeV
in different topological regions of the events. Particle transverse momentum (pT) spectra are
measured in the âtowardâ, âtransverseâ, and âawayâ angular regions defined with respect
to the direction of the leading particle in the event. While the toward and away regions
contain the fragmentation products of the near-side and away-side jets, respectively, the
transverse region is dominated by particles from the Underlying Event (UE). The relative
transverse activity classifier, RT = NT/ăNTă, is used to group events according to their UE
activity, where NT is the measured charged-particle multiplicity per event in the transverse
region and ăNTă is the mean value over all the analysed events. The first measurements
of identified particle pT spectra as a function of RT in the three topological regions are
reported. It is found that the yield of high transverse momentum particles relative to the
RT-integrated measurement decreases with increasing RT in both the toward and the away
regions, indicating that the softer UE dominates particle production as RT increases and
validating that RT can be used to control the magnitude of the UE. Conversely, the spectral
shapes in the transverse region harden significantly with increasing RT. This hardening
follows a mass ordering, being more significant for heavier particles. Finally, it is observed
that the pT-differential particle ratios (p + p )/(Ï+ + Ïâ) and (K+ + Kâ)/(Ï+ + Ïâ) in
the low UE limit (RT â 0) approach expectations from Monte Carlo generators such as
PYTHIA 8 with Monash 2013 tune and EPOS LHC, where the jet-fragmentation models
have been tuned to reproduce e+eâ results
The genetic architecture of the human cerebral cortex
The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder
ARDD 2020: from aging mechanisms to interventions
Aging is emerging as a druggable target with growing interest from academia, industry and investors. New technologies such as artificial intelligence and advanced screening techniques, as well as a strong influence from the industry sector may lead to novel discoveries to treat age-related diseases. The present review summarizes presentations from the 7th Annual Aging Research and Drug Discovery (ARDD) meeting, held online on the 1st to 4th of September 2020. The meeting covered topics related to new methodologies to study aging, knowledge about basic mechanisms of longevity, latest interventional strategies to target the aging process as well as discussions about the impact of aging research on society and economy. More than 2000 participants and 65 speakers joined the meeting and we already look forward to an even larger meeting next year. Please mark your calendars for the 8th ARDD meeting that is scheduled for the 31st of August to 3rd of September, 2021, at Columbia University, USA
Genomic investigations of unexplained acute hepatitis in children
Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children
Suppression in Pb-Pb Collisions at the LHC.
The production of the Ï(2S) charmonium state was measured with ALICE in Pb-Pb collisions at sqrt[s_{NN}]=5.02ââTeV, in the dimuon decay channel. A significant signal was observed for the first time at LHC energies down to zero transverse momentum, at forward rapidity (2.5<y<4). The measurement of the ratio of the inclusive production cross sections of the Ï(2S) and J/Ï resonances is reported as a function of the centrality of the collisions and of transverse momentum, in the region p_{T}<12ââGeV/c. The results are compared with the corresponding measurements in pp collisions, by forming the double ratio [Ï^{Ï(2S)}/Ï^{J/Ï}]_{Pb-Pb}/[Ï^{Ï(2S)}/Ï^{J/Ï}]_{pp}. It is found that in Pb-Pb collisions the Ï(2S) is suppressed by a factor of âŒ2 with respect to the J/Ï. The Ï(2S) nuclear modification factor R_{AA} was also obtained as a function of both centrality and p_{T}. The results show that the Ï(2S) resonance yield is strongly suppressed in Pb-Pb collisions, by a factor of up to âŒ3 with respect to pp. Comparisons of cross section ratios with previous Super Proton Synchrotron findings by the NA50 experiment and of R_{AA} with higher-p_{T} results at LHC energy are also reported. These results and the corresponding comparisons with calculations of transport and statistical models address questions on the presence and properties of charmonium states in the quark-gluon plasma formed in nuclear collisions at the LHC
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