774 research outputs found
P2_6 Surfin' Fury
In a short film called Kung Fury, the main hero uses a person as a surfing board. We investigated the force he would need to push himself forward based on the kinetic friction and drag force. The force ranges between -335.24 ± 6.87 N and -980.74 ± 6.87 N
Distinct Cortical Circuit Mechanisms for Complex Forelimb Movement and Motor Map Topography
SummaryCortical motor maps are the basis of voluntary movement, but they have proven difficult to understand in the context of their underlying neuronal circuits. We applied light-based motor mapping of Channelrhodopsin-2 mice to reveal a functional subdivision of the forelimb motor cortex based on the direction of movement evoked by brief (10 ms) pulses. Prolonged trains of electrical or optogenetic stimulation (100–500 ms) targeted to anterior or posterior subregions of motor cortex evoked reproducible complex movements of the forelimb to distinct positions in space. Blocking excitatory cortical synaptic transmission did not abolish basic motor map topography, but the site-specific expression of complex movements was lost. Our data suggest that the topography of movement maps arises from their segregated output projections, whereas complex movements evoked by prolonged stimulation require intracortical synaptic transmission
P2_4 Not So Spontaneous Combustion
In the X-Files TV series, a man is injected with a chemical that freezes him. When defrosting, his bodystarts producing exothermic reaction that sets him on re. At normal metabolic rate, this reaction wouldtake at least 4 days 15 hours and 24 minutes. In the time scale of the show the energy required to heatthe body would be 9.9 x 105 W
P2_1 In a Blink of an Eye
The game World of Warcraft allows a mage to teleport a short distance in almost an instant. Based on the description of the spell, we calculated the acceleration of the mage as 82.86 ± 13.96g. We then compared the acceleration of the mage to those that people are able to survive in real life
Risk-adjusted survival for adults following in-hospital cardiac arrest by day of week and time of day: Observational cohort study
Background: Internationally, hospital survival is lower for patients admitted at weekends and at night. Data from the UK National Cardiac Arrest Audit (NCAA) indicate that crude hospital survival was worse after in-hospital cardiac arrest (IHCA) at night versus day, and at weekends versus weekdays, despite similar frequency of events. Objective: To describe IHCA demographics during three day/time periods - weekday daytime (Monday to Friday, 08:00 to 19:59), weekend daytime (Saturday and Sunday, 08:00 to 19:59) and night-time (Monday to Sunday, 20:00 to 07:59) - and to compare the associated rates of return of spontaneous circulation (ROSC) for >20 min (ROSC>20 min) and survival to hospital discharge, adjusted for risk using previously developed NCAA risk models. To consider whether any observed difference could be attributed to differences in the case mix of patients resident in hospital and/or the administered care. Methods: We performed a prospectively defined analysis of NCAA data from 27 700 patients aged ≥16 years receiving chest compressions and/or defibrillation and attended by a hospital-based resuscitation team in response to a resuscitation (2222) call in 146 UK acute hospitals. Results: Risk-adjusted outcomes (OR (95% CI)) were worse (p20 min 0.88 (0.81 to 0.95); hospital survival 0.72 (0.64 to 0.80)), and nighttime (ROSC>20 min 0.72 (0.68 to 0.76); hospital survival 0.58 (0.54 to 0.63)) compared with weekday daytime. The effects were stronger for non-shockable than shockable rhythms, but there was no significant interaction between day/ time of arrest and age, or day/time of arrest and arrest location. While many daytime IHCAs involved procedures, restricting the analyses to IHCAs in medical admissions with an arrest location of ward produced results that are broadly in line with the primary analyses. Conclusions: IHCAs attended by the hospital-based resuscitation team during nights and weekends have substantially worse outcomes than during weekday daytimes. Organisational or care differences at night and weekends, rather than patient case mix, appear to be responsible
Detecting the (Quasi-)Two-Body Decays of Leptons in Short-Baseline Neutrino Oscillation Experiments
Novel detector schemes are proposed for the short-baseline neutrino
experiments of next generation, aimed at exploring the large-
domain of \omutau oscillations in the appearance mode. These schemes emphasize
good spectrometry for charged particles and for electromagnetic showers and
efficient reconstruction of \ypi_gg decays. The basic elements are a sequence
of relatively thin emulsion targets, immersed in magnetic field and
interspersed with electronic trackers, and a fine-grained electromagnetic
calorimeter built of lead glass. These elements act as an integral whole in
reconstructing the electromagnetic showers. This conceptual scheme shows good
performance in identifying the (quasi-)two-body decays by their
characteristic kinematics and in selecting the electronic decays of the .Comment: 34 pages, 8 figure
Electronic and thermal sequential transport in metallic and superconducting two-junction arrays
The description of transport phenomena in devices consisting of arrays of
tunnel junctions, and the experimental confirmation of these predictions is one
of the great successes of mesoscopic physics. The aim of this paper is to give
a self-consistent review of sequential transport processes in such devices,
based on the so-called "orthodox" model. We calculate numerically the
current-voltage (I-V) curves, the conductance versus bias voltage (G-V) curves,
and the associated thermal transport in symmetric and asymmetric two-junction
arrays such as Coulomb-blockade thermometers (CBTs),
superconducting-insulator-normal-insulator-superconducting (SINIS) structures,
and superconducting single-electron transistors (SETs). We investigate the
behavior of these systems at the singularity-matching bias points, the
dependence of microrefrigeration effects on the charging energy of the island,
and the effect of a finite superconducting gap on Coulomb-blockade thermometry.Comment: 23 pages, 12 figures; Berlin (ISBN: 978-3-642-12069-5
Simulations of the Static Friction Due to Adsorbed Molecules
The static friction between crystalline surfaces separated by a molecularly
thin layer of adsorbed molecules is calculated using molecular dynamics
simulations. These molecules naturally lead to a finite static friction that is
consistent with macroscopic friction laws. Crystalline alignment, sliding
direction, and the number of adsorbed molecules are not controlled in most
experiments and are shown to have little effect on the friction. Temperature,
molecular geometry and interaction potentials can have larger effects on
friction. The observed trends in friction can be understood in terms of a
simple hard sphere model.Comment: 13 pages, 13 figure
MYCN expression induces replication stress and sensitivity to PARP inhibition in neuroblastoma
This study investigates the influence expression of the MYCN oncogene has on the DNA damage response, replication fork progression and sensitivity to PARP inhibition in neuroblastoma. In a panel of neuroblastoma cell lines, MYCN amplification or MYCN expression resulted in increased cell death in response to a range of PARP inhibitors (niraparib, veliparib, talazoparib and olaparib) compared to the response seen in non-expressing/amplified cells. MYCN expression slowed replication fork speed and increased replication fork stalling, an effect that was amplified by PARP inhibition or PARP1 depletion. Increased DNA damage seen was specifically induced in S-phase cells. Importantly, PARP inhibition caused a significant increase in the survival of mice bearing MYCN expressing tumours in a transgenic murine model of MYCN expressing neuroblastoma. Olaparib also sensitized MYCN expressing cells to camptothecin- and temozolomide-induced cell death to a greater degree than non-expressing cells. In summary, MYCN expression leads to increased replication stress in neuroblastoma cells. This effect is exaggerated by inhibition of PARP, resulting in S-phase specific DNA damage and ultimately increased tumour cell death. PARP inhibition alone or in combination with classical chemotherapeutics is therefore a potential therapeutic strategy for neuroblastoma and may be more effective in MYCN expressing tumours
Clastic Polygonal Networks Around Lyot Crater, Mars: Possible Formation Mechanisms From Morphometric Analysis
Polygonal networks of patterned ground are a common feature in cold-climate environments. They can form through the thermal contraction of ice-cemented sediment (i.e. formed from fractures), or the freezing and thawing of ground ice (i.e. formed by patterns of clasts, or ground deformation). The characteristics of these landforms provide information about environmental conditions. Analogous polygonal forms have been observed on Mars leading to inferences about environmental conditions. We have identified clastic polygonal features located around Lyot crater, Mars (50°N, 30°E). These polygons are unusually large (> 100 m diameter) compared to terrestrial clastic polygons, and contain very large clasts, some of which are up to 15 metres in diameter. The polygons are distributed in a wide arc around the eastern side of Lyot crater, at a consistent distance from the crater rim. Using high-resolution imaging data, we digitised these features to extract morphological information. These data are compared to existing terrestrial and Martian polygon data to look for similarities and differences and to inform hypotheses concerning possible formation mechanisms. Our results show the clastic polygons do not have any morphometric features that indicate they are similar to terrestrial sorted, clastic polygons formed by freeze-thaw processes. They are too large, do not show the expected variation in form with slope, and have clasts that do not scale in size with polygon diameter. However, the clastic networks are similar in network morphology to thermal contraction cracks, and there is a potential direct Martian analogue in a sub-type of thermal contraction polygons located in Utopia Planitia. Based upon our observations, we reject the hypothesis that polygons located around Lyot formed as freeze-thaw polygons and instead an alternative mechanism is put forward: they result from the infilling of earlier thermal contraction cracks by wind-blown material, which then became compressed and/or cemented resulting in a resistant fill. Erosion then leads to preservation of these polygons in positive relief, while later weathering results in the fracturing of the fill material to form angular clasts. These results suggest that there was an extensive area of ice-rich terrain, the extent of which is linked to ejecta from Lyot crater
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