427 research outputs found
Sensation of presence and cybersickness in applications of virtual reality for advanced rehabilitation
Around three years ago, in the special issue on augmented and virtual reality in rehabilitation, the topics of simulator sickness was briefly discussed in relation to vestibular rehabilitation. Simulator sickness with virtual reality applications have also been referred to as visually induced motion sickness or cybersickness. Recently, study on cybersickness has been reported in entertainment, training, game, and medical environment in several journals. Virtual stimuli can enlarge sensation of presence, but they sometimes also evoke unpleasant sensation. In order to safely apply augmented and virtual reality for long-term rehabilitation treatment, sensation of presence and cybersickness should be appropriately controlled. This issue presents the results of five studies conducted to evaluate visually-induced effects and speculate influences of virtual rehabilitation. In particular, the influence of visual and vestibular stimuli on cardiovascular responses are reported in terms of academic contribution
Information transmission in oscillatory neural activity
Periodic neural activity not locked to the stimulus or to motor responses is
usually ignored. Here, we present new tools for modeling and quantifying the
information transmission based on periodic neural activity that occurs with
quasi-random phase relative to the stimulus. We propose a model to reproduce
characteristic features of oscillatory spike trains, such as histograms of
inter-spike intervals and phase locking of spikes to an oscillatory influence.
The proposed model is based on an inhomogeneous Gamma process governed by a
density function that is a product of the usual stimulus-dependent rate and a
quasi-periodic function. Further, we present an analysis method generalizing
the direct method (Rieke et al, 1999; Brenner et al, 2000) to assess the
information content in such data. We demonstrate these tools on recordings from
relay cells in the lateral geniculate nucleus of the cat.Comment: 18 pages, 8 figures, to appear in Biological Cybernetic
Midlife muscle strength and human longevity up to age 100 years: a 44-year prospective study among a decedent cohort
We studied prospectively the midlife handgrip strength, living habits, and parentsâ longevity as predictors of length of life up to becoming a centenarian. The participants were 2,239 men from the Honolulu Heart Program/HonoluluâAsia Aging Study who were born before the end of June 1909 and who took part in baseline physical assessment in 1965â1968, when they were 56â68 years old. Deaths were followed until the end of June 2009 for 44 years with complete ascertainment. Longevity was categorized as centenarian (â„100 years, nâ=â47), nonagenarian (90â99 years, nâ=â545), octogenarian (80â89 years, nâ=â847), and â€79 years (nâ=â801, reference). The average survival after baseline was 20.8 years (SDâ=â9.62). Compared with people who died at the age of â€79 years, centenarians belonged 2.5 times (odds ratio (OR)â=â2.52, 95% confidence interval (CI)â=â1.23â5.10) more often to the highest third of grip strength in midlife, were never smokers (ORâ=â5.75 95% CIâ=â3.06â10.80), had participated in physical activity outside work (ORâ=â1.13 per daily hour, 95% CIâ=â1.02â1.25), and had a long-lived mother (â„80 vs. â€60 years, ORâ=â2.3, 95% CIâ=â1.06â5.01). Associations for nonagenarians and octogenarians were parallel, but weaker. Multivariate modeling showed that motherâs longevity and offspringâs grip strength operated through the same or overlapping pathway to longevity. High midlife grip strength and long-lived mother may indicate resilience to aging, which, combined with healthy lifestyle, increases the probability of extreme longevity
The use of a Psoroptes ovis serodiagnostic test for the analysis of a natural outbreak of sheep scab
<p>Abstract</p> <p>Background</p> <p>Sheep scab is a highly contagious disease of sheep caused by the ectoparasitic mite <it>Psoroptes ovis</it>. The disease is endemic in the UK and has significant economic impact through its effects on performance and welfare. Diagnosis of sheep scab is achieved through observation of clinical signs e.g. itching, pruritis and wool loss and ultimately through the detection of mites in skin scrapings. Early stages of infestation are often difficult to diagnose and sub-clinical animals can be a major factor in disease spread. The development of a diagnostic assay would enable farmers and veterinarians to detect disease at an early stage, reducing the risk of developing clinical disease and limiting spread.</p> <p>Methods</p> <p>Serum samples were obtained from an outbreak of sheep scab within an experimental flock (n = 480 (3 samples each from 160 sheep)) allowing the assessment, by ELISA of sheep scab specific antibody prior to infestation, mid-outbreak (combined with clinical assessment) and post-treatment.</p> <p>Results</p> <p>Analysis of pre-infestation samples demonstrated low levels of potential false positives (3.8%). Of the 27 animals with clinical or behavioural signs of disease 25 tested positive at the mid-outbreak sampling period, however, the remaining 2 sheep tested positive at the subsequent sampling period. Clinical assessment revealed the absence of clinical or behavioural signs of disease in 132 sheep, whilst analysis of mid-outbreak samples showed that 105 of these clinically negative animals were serologically positive, representing potential sub-clinical infestations.</p> <p>Conclusions</p> <p>This study demonstrates that this ELISA test can effectively diagnose sheep scab in a natural outbreak of disease, and more importantly, highlights its ability to detect sub-clinically infested animals. This ELISA, employing a single recombinant antigen, represents a major step forward in the diagnosis of sheep scab and may prove to be critical in any future control program.</p
FORG3D: Force-directed 3D graph editor for visualization of integrated genome scale data
<p>Abstract</p> <p>Background</p> <p>Genomics research produces vast amounts of experimental data that needs to be integrated in order to understand, model, and interpret the underlying biological phenomena. Interpreting these large and complex data sets is challenging and different visualization methods are needed to help produce knowledge from the data.</p> <p>Results</p> <p>To help researchers to visualize and interpret integrated genomics data, we present a novel visualization method and bioinformatics software tool called FORG3D that is based on real-time three-dimensional force-directed graphs. FORG3D can be used to visualize integrated networks of genome scale data such as interactions between genes or gene products, signaling transduction, metabolic pathways, functional interactions and evolutionary relationships. Furthermore, we demonstrate its utility by exploring gene network relationships using integrated data sets from a <it>Caenorhabditis elegans </it>Parkinson's disease model.</p> <p>Conclusion</p> <p>We have created an open source software tool called FORG3D that can be used for visualizing and exploring integrated genome scale data.</p
A Transcription Elongation Factor That Links Signals from the Reproductive System to Lifespan Extension in Caenorhabditis elegans
In Caenorhabditis elegans and Drosophila melanogaster, the aging of the soma is influenced by the germline. When germline-stem cells are removed, aging slows and lifespan is increased. The mechanism by which somatic tissues respond to loss of the germline is not well-understood. Surprisingly, we have found that a predicted transcription elongation factor, TCER-1, plays a key role in this process. TCER-1 is required for loss of the germ cells to increase C. elegans' lifespan, and it acts as a regulatory switch in the pathway. When the germ cells are removed, the levels of TCER-1 rise in somatic tissues. This increase is sufficient to trigger key downstream events, as overexpression of tcer-1 extends the lifespan of normal animals that have an intact reproductive system. Our findings suggest that TCER-1 extends lifespan by promoting the expression of a set of genes regulated by the conserved, life-extending transcription factor DAF-16/FOXO. Interestingly, TCER-1 is not required for DAF-16/FOXO to extend lifespan in animals with reduced insulin/IGF-1 signaling. Thus, TCER-1 specifically links the activity of a broadly deployed transcription factor, DAF-16/FOXO, to longevity signals from reproductive tissues
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The secretome of alginate-encapsulated limbal epithelial stem cells modulates corneal epithelial cell proliferation
Limbal epithelial stem cells may ameliorate limbal stem cell deficiency through secretion of therapeutic proteins, delivered to the cornea in a controlled manner using hydrogels. In the present study the secretome of alginate-encapsulated limbal epithelial stem cells is investigated. Conditioned medium was generated from limbal epithelial stem cells encapsulated in 1.2% (w/v) calcium alginate gels. Conditioned medium proteins separated by 1-D gel electrophoresis were visualized by silver staining. Proteins of interest including secreted protein acidic and rich in cysteine, profilin-1, and galectin-1 were identified by immunoblotting. The effect of conditioned medium (from alginate-encapsulated limbal epithelial stem cells) on corneal epithelial cell proliferation was quantified and shown to significantly inhibit (P</=0.05) their growth. As secreted protein acidic and rich in cysteine was previously reported to attenuate proliferation of epithelial cells, this protein may be responsible, at least in part, for inhibition of corneal epithelial cell proliferation. We conclude that limbal epithelial stem cells encapsulated in alginate gels may regulate corneal epithelialisation through secretion of inhibitory proteins
Compensatory movements during functional activities in ambulatory children with Duchenne muscular dystrophy
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of âs = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pTâ„20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60â€pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2â€{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
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