3,332 research outputs found
Tunneling-percolation origin of nonuniversality: theory and experiments
A vast class of disordered conducting-insulating compounds close to the
percolation threshold is characterized by nonuniversal values of transport
critical exponent t, in disagreement with the standard theory of percolation
which predicts t = 2.0 for all three dimensional systems. Various models have
been proposed in order to explain the origin of such universality breakdown.
Among them, the tunneling-percolation model calls into play tunneling processes
between conducting particles which, under some general circumstances, could
lead to transport exponents dependent of the mean tunneling distance a. The
validity of such theory could be tested by changing the parameter a by means of
an applied mechanical strain. We have applied this idea to universal and
nonuniversal RuO2-glass composites. We show that when t > 2 the measured
piezoresistive response \Gamma, i. e., the relative change of resistivity under
applied strain, diverges logarithmically at the percolation threshold, while
for t = 2, \Gamma does not show an appreciable dependence upon the RuO2 volume
fraction. These results are consistent with a mean tunneling dependence of the
nonuniversal transport exponent as predicted by the tunneling-percolation
model. The experimental results are compared with analytical and numerical
calculations on a random-resistor network model of tunneling-percolation.Comment: 13 pages, 12 figure
Anatomy of sartorius muscle
A sartorius muscle is the longest muscle of the human system. It runs over 2 joints— hip and knee joints. In the study 10 sartorius muscles were examined. They were dissected free of lower human limbs. Dimensions of limbs which these muscles come from and dimensions of the muscles and their component parts were examined. The attention was paid mainly to parts of tendon located inside the muscle belly. The results show that they are either of a comparable length (distal tendon) or several times longer (proximal tendon) than visible parts located outside of the muscle. Moreover, a complex structure of the distal tendon which includes 2 tracts of different places of insertion was stated. Inferior tract inserted in the same place as muscle tendons: semitendinosus and gracilis. The superior tract inserted transversely against the former one. The tendon of the sartorius muscle forms additionally an aponeurosis whose fibres enter into the deep fascia of crus. The muscle belly is characterised with various width on different levels of its length. In half of casess word-like distal segment of belly is formed
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13 TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector
Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente
Anatomy of the long peroneal muscle of the leg
Background: The aim of the work was to perform a morphometric analysis of the long peroneal muscle (LPM) of the leg and explore the relationship between muscle belly and tendon.
Materials and methods: Ten lower limbs (8 right and 2 left) were fixed in formaldehyde and dissected using standard technique. The LPM was exposed from the proximal attachment to the top of a lateral malleolus.
Results: The tendon was subsequently freed and various measurements were taken. The tendon of the LPM enters deep into the muscle belly. Muscle fibres surround the tendon and descend as far down as 4 cm above the lateral malleolus. Muscle fibres insert mainly along posterior border of the tendon and on its medial surface, leaving lateral surface only partly covered.
Conclusions: The LPM contains a long intramuscular segment of the tendon and area of the musculotendinous junction varies along the LPM. It makes the idea of uniform pennation pattern of the LPM unlikely
Morphology and morphometry of the semitendinosus distal tendon in adults and foetuses
Background: The distal tendon of the semitendinosus is often used as a graft in orthopedic reconstructive surgery. Knowledge of the exact morphology of this tendon, and also the ability to predict its morphometric data are certainly helpful when planning the procedure of surgery. Comparison of the semitendinosus distal tendon anatomy in adults and foetuses may be scientifically relevant. There are no scientific reports on this tendon anatomy in foetuses.
Materials and methods: Seventy semitendinosus muscles from cadavers were obtained using standard dissection techniques (50 muscles were obtained from adults and 20 from foetuses). Moreover, ultrasound examinations of 20 muscles were performed in living individuals.
Results: Two main parts of the distal tendon were distinguished — the external part not covered with muscle fibres and the internal part, which is partially or entirely hidden within the muscle belly (venter). The average length of the distal tendon was 32.34 cm, while the average lengths of the external and internal parts were 9.65 cm and 12.59 cm, respectively. The external part was solid and cylindrical. The internal part was flat and rolled like a trough, thus making the tendon a poor transplant material. Similarly, the distal tendon in foetuses consisted of two parts, including the external and internal part.
Conclusions: The proportions between the lengths of different muscle parts were very similar in adults and foetuses
Dimensionality of Carbon Nanomaterials Determines the Binding and Dynamics of Amyloidogenic Peptides: Multiscale Theoretical Simulations
Experimental studies have demonstrated that nanoparticles can affect the rate of protein self-assembly, possibly interfering with the development of protein misfolding diseases such as Alzheimer's, Parkinson's and prion disease caused by aggregation and fibril formation of amyloid-prone proteins. We employ classical molecular dynamics simulations and large-scale density functional theory calculations to investigate the effects of nanomaterials on the structure, dynamics and binding of an amyloidogenic peptide apoC-II(60-70). We show that the binding affinity of this peptide to carbonaceous nanomaterials such as C60, nanotubes and graphene decreases with increasing nanoparticle curvature. Strong binding is facilitated by the large contact area available for π-stacking between the aromatic residues of the peptide and the extended surfaces of graphene and the nanotube. The highly curved fullerene surface exhibits reduced efficiency for π-stacking but promotes increased peptide dynamics. We postulate that the increase in conformational dynamics of the amyloid peptide can be unfavorable for the formation of fibril competent structures. In contrast, extended fibril forming peptide conformations are promoted by the nanotube and graphene surfaces which can provide a template for fibril-growth
Breakup of finite-size liquid filaments: Transition from no-breakup to breakup including substrate effects
This work studies the breakup of finite-size liquid filaments, when also
including substrate effects, using direct numerical simulations. The study
focuses on the effects of three parameters: Ohnesorge number, the ratio of the
viscous forces to inertial and surface tension forces, the liquid filament
aspect ratio, and where there is a substrate, a measure of the fluid slip on
the substrate, i.e. slip length. Through these parameters, it is determined
whether a liquid filament breaks up during the evolution toward its final
equilibrium state. Three scenarios are identified: a collapse into a single
droplet, the breakup into one or multiple droplets, and recoalescence into a
single droplet after the breakup (or even possibly another breakup after
recoalescence). The results are compared with the ones available in the
literature for free-standing liquid filaments. The findings show that the
presence of the substrate promotes breakup of the filament. The effect of the
degree of slip on the breakup is also discussed. The parameter domain regions
are comprehensively explored when including the slip effects. An experimental
case is also carried out to illustrate the collapse and breakup of a
finite-size silicon oil filament supported on a substrate, showcasing a
critical length of the breakup in a physical configuration. Finally, direct
numerical simulations reveal striking new details into the breakup pattern for
low Ohnesorge numbers, where the dynamics are fast and the experimental imaging
is not available; our results therefore significantly extend the range of
Ohnesorge number over which filament breakup has been considered
Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus -- the "D-shuttle" project --
Twelve high schools in Japan (of which six are in Fukushima Prefecture), four
in France, eight in Poland and two in Belarus cooperated in the measurement and
comparison of individual external doses in 2014. In total 216 high-school
students and teachers participated in the study. Each participant wore an
electronic personal dosimeter "D-shuttle" for two weeks, and kept a journal of
his/her whereabouts and activities. The distributions of annual external doses
estimated for each region overlap with each other, demonstrating that the
personal external individual doses in locations where residence is currently
allowed in Fukushima Prefecture and in Belarus are well within the range of
estimated annual doses due to the background radiation level of other
regions/countries
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