Pharmacological Or Genetic Targeting Of Transient Receptor Potential (TRP) Channels Can Disrupt The Planarian Escape Response

In response to noxious stimuli, planarians cease their typical ciliary gliding and exhibit an oscillatory type of locomotion called scrunching. We have previously characterized the biomechanics of scrunching and shown that it is induced by specific stimuli, such as amputation, noxious heat, and extreme pH. Because these specific inducers are known to activate Transient Receptor Potential (TRP) channels in other systems, we hypothesized that TRP channels control scrunching. We found that chemicals known to activate TRPA1 (allyl isothiocyanate (AITC) and hydrogen peroxide) and TRPV (capsaicin and anandamide) in other systems induce scrunching in the planarian species Dugesia japonica and, except for anandamide, in Schmidtea mediterranea. To confirm that these responses were specific to either TRPA1 or TRPV, respectively, we tried to block scrunching using selective TRPA1 or TRPV antagonists and RNA interference (RNAi) mediated knockdown. Unexpectedly, co-treatment with a mammalian TRPA1 antagonist, HC-030031, enhanced AITC-induced scrunching by decreasing the latency time, suggesting an agonistic relationship in planarians. We further confirmed that TRPA1 in both planarian species is necessary for AITC-induced scrunching using RNAi. Conversely, while co-treatment of a mammalian TRPV antagonist, SB-366791, also enhanced capsaicin-induced reactions in D. japonica, combined knockdown of two previously identified D. japonica TRPV genes (DjTRPVa and DjTRPVb) did not inhibit capsaicin-induced scrunching. RNAi of DjTRPVa/DjTRPVb attenuated scrunching induced by the endocannabinoid and TRPV agonist, anandamide. Overall, our results show that although scrunching induction can involve different initial pathways for sensing stimuli, this behavior’s signature dynamical features are independent of the inducer, implying that scrunching is a stereotypical planarian escape behavior in response to various noxious stimuli that converge on a single downstream pathway. Understanding which aspects of nociception are conserved or not across different organisms can provide insight into the underlying regulatory mechanisms to better understand pain sensation

Tectonic evolution of 200 km of Mid-Atlantic Ridge over 10 million years : interplay of volcanism and faulting

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry, Geophysics, Geosystems 16 (2015): 2303-2321, doi:10.1002/2015GC005797.We reconstruct the history of the mode of accretion of an area of the Mid-Atlantic Ridge south of the Kane fracture zone using bathymetric morphology. The area includes 200 km of the spreading axis and reaches to 10 Ma on either side. We distinguish three tectonic styles: (1) volcanic construction with eruption and intrusion of magma coupled with minor faulting, (2) extended terrain with abundant large-offset faults, (3) detachment faulting marked by extension on single long-lived faults. Over 40% of the seafloor is made of extended terrain and detachment faults. The area includes products of seven spreading segments. The spreading axis has had detachment faulting or extended terrain on one or both sides for 70% of the last 10 Ma. In some parts of the area, regions of detachment faulting and extended terrain lie close to segment boundaries. Regions of detachment faulting initiated at 10 Ma close to the adjacent fracture zones to the north and south, and then expanded away from them. We discuss the complex evidence from gravity, seismic surveys, and bathymetry for the role of magma supply in generating tectonic style. Overall, we conclude that input of magma at the spreading axis has a general control on the development of detachment faulting, but the relationship is not strong. Other factors may include a positive feedback that stabilizes detachment faulting at the expense of volcanic extension, perhaps through the lubrication of active detachment faults by the formation of low friction materials (talc, serpentine) on detachment fault surfaces.2016-01-2

Universal quantum computation with the Orbital Angular Momentum of a single photon

We prove that a single photon with quantum data encoded in its orbital angular momentum can be manipulated with simple optical elements to provide any desired quantum computation. We will show how to build any quantum unitary operator using beamsplitters, phase shifters, holograms and an extraction gate based on quantum interrogation. The advantages and challenges of these approach are then discussed, in particular the problem of the readout of the results.Comment: First version. Comments welcom

Type Ia supernovae and the ^{12}C+^{12}C reaction rate

The experimental determination of the cross-section of the ^{12}C+^{12}C reaction has never been made at astrophysically relevant energies (E<2 MeV). The profusion of resonances throughout the measured energy range has led to speculation that there is an unknown resonance at E\sim1.5 MeV possibly as strong as the one measured for the resonance at 2.14 MeV. We study the implications that such a resonance would have for the physics of SNIa, paying special attention to the phases that go from the crossing of the ignition curve to the dynamical event. We use one-dimensional hydrostatic and hydrodynamic codes to follow the evolution of accreting white dwarfs until they grow close to the Chandrasekhar mass and explode as SNIa. In our simulations, we account for a low-energy resonance by exploring the parameter space allowed by experimental data. A change in the ^{12}C+^{12}C rate similar to the one explored here would have profound consequences for the physical conditions in the SNIa explosion, namely the central density, neutronization, thermal profile, mass of the convective core, location of the runaway hot spot, or time elapsed since crossing the ignition curve. For instance, with the largest resonance strength we use, the time elapsed since crossing the ignition curve to the supernova event is shorter by a factor ten than for models using the standard rate of ^{12}C+^{12}C, and the runaway temperature is reduced from \sim8.14\times10^{8} K to \sim4.26\times10^{8} K. On the other hand, a resonance at 1.5 MeV, with a strength ten thousand times smaller than the one measured at 2.14 MeV, but with an {\alpha}/p yield ratio substantially different from 1 would have a sizeable impact on the degree of neutronization of matter during carbon simmering. We conclude that a robust understanding of the links between SNIa properties and their progenitors will not be attained until the ^{12}C+^{12}C reaction rate is measured at energies \sim1.5 MeV.Comment: 15 pages, 6 tables, 10 figures, accepted for Astronomy and Astrophysic

Colloquium: Mechanical formalisms for tissue dynamics

The understanding of morphogenesis in living organisms has been renewed by tremendous progressin experimental techniques that provide access to cell-scale, quantitative information both on theshapes of cells within tissues and on the genes being expressed. This information suggests that ourunderstanding of the respective contributions of gene expression and mechanics, and of their crucialentanglement, will soon leap forward. Biomechanics increasingly benefits from models, which assistthe design and interpretation of experiments, point out the main ingredients and assumptions, andultimately lead to predictions. The newly accessible local information thus calls for a reflectionon how to select suitable classes of mechanical models. We review both mechanical ingredientssuggested by the current knowledge of tissue behaviour, and modelling methods that can helpgenerate a rheological diagram or a constitutive equation. We distinguish cell scale ("intra-cell")and tissue scale ("inter-cell") contributions. We recall the mathematical framework developpedfor continuum materials and explain how to transform a constitutive equation into a set of partialdifferential equations amenable to numerical resolution. We show that when plastic behaviour isrelevant, the dissipation function formalism appears appropriate to generate constitutive equations;its variational nature facilitates numerical implementation, and we discuss adaptations needed in thecase of large deformations. The present article gathers theoretical methods that can readily enhancethe significance of the data to be extracted from recent or future high throughput biomechanicalexperiments.Comment: 33 pages, 20 figures. This version (26 Sept. 2015) contains a few corrections to the published version, all in Appendix D.2 devoted to large deformation

A counterfactual Rydberg gate for photons

Quantum computation with photons requires efficient two photon gates. We put forward a two photon entangling gate which uses an intermediate atomic system. The system includes a single Rydberg atom which can switch on and off photon absorption in an ensemble using the dipole blockade. The gate is based in a counterfactual protocol. The mere possibility of an absorption that can only occur with a vanishing probability steers the photons to the desired final state.Comment: 4 Figures. 6 pages of tex

Blending mindfulness practices and character strengths increases employee well‐being : a second‐order meta‐analysis and a follow‐up field experiment

Abstract: This study summarises the existing literature on Mindfulness‐Based Interventions (MBIs) and their effect on employee well‐being criteria and extends it by testing MBIs against a Mindfulness‐Strengths‐Based Intervention (MSBI). Given that extant MBIs focus on restoring well‐being, our first hypothesis was that MBIs would perform better on reducing negative emotional states than on promoting wellbeing. To test our first hypothesis, we conducted a secondorder meta‐analysis, which summarised 13 first‐order meta‐analyses (k = 311). MBIs had stronger effects on reducing negative emotions (g = −0.74) than on increasing well‐being (g = 0.58). Then, we conducted a follow‐up field experiment, comparing how an MSBI performed against an MBI on employee well‐being criteria..

A record of eruption and intrusion at a fast spreading ridge axis : axial summit trough of the East Pacific Rise at 9–10°N

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 10 (2009): Q10T07, doi:10.1029/2008GC002354.High-resolution side-scan sonar, near-bottom multibeam bathymetry, and deep-sea photo and bathymetry traverses are used to map the axial summit trough (AST) at the East Pacific Rise between 9 and 10°N. We define three ridge axis morphologic types: no AST, narrow AST, and wide AST, which characterize distinct ridge crest domains spanning tens of kilometers along strike. Near-bottom observations, modeling of deformation above intruding dikes, and comparisons to the geologic and geophysical structure of the ridge crest are used to develop a revised model of AST genesis and evolution. This model helps constrain the record of intrusive and extrusive magmatism and styles of lava deposition along the ridge crest at time scales from hundreds to tens of thousands of years. The grabens in the narrow-AST domain (9°43′–53′N) are consistent with deformation above the most recent (<10) diking events beneath the ridge crest. Frequent high–effusion rate extrusive volcanism in this domain (several eruptions every ∼100 years) overprints near-axis deformation and maintains a consistent AST width. The most recent eruption at the ridge crest occurred in this area and did not significantly modify the physical characteristics of the AST. The grabens in the wide-AST domain (9°23′–43′N) originated with similar dimensions to the narrow AST. Spreading, driven primarily by the intrusion of shallow dikes within a narrow axial zone, causes the initial graben bounding faults to migrate away from the axis. Infrequent extrusive volcanism (several eruptions every ∼1000 years) fills a portion of the subsidence that accumulates over time but does not significantly modify the width of the AST. Outside of these domains, lower–effusion rate constructional volcanism without efficient drain-back fills and erases the signature of the AST. The relative frequency of intrusive versus extrusive magmatic events controls the morphology of the ridge crest and appears to remain constant over millennial time scales within the domains we have identified; however, over longer time scales (∼10–25 ka), domain-specific intrusive-to-extrusive ratios do not appear to be fixed in space, resulting in a fairly consistent volcanic accretion over the length scale of the second-order ridge segment between 9°N and 10°N.This work was supported by NSF grants OCE-0525863 to D. Fornari and S. A. Soule; OCE-0732366 to S. A. Soule; and OCE-9819261 to H. Schouten, M. Tivey, and D. Fornari and by CNRS to J. Escartın

Monitoring the lucky strike vent field in real time

Peer Reviewe

Primary Black Hole Spin in OJ 287 as Determined by the General Relativity Centenary Flare

OJ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in a binary black hole model. The model predicted a major optical outburst in 2015 December. We found that the outburst did occur within the expected time range, peaking on 2015 December 5 at magnitude 12.9 in the optical R -band. Based on Swift /XRT satellite measurements and optical polarization data, we find that it included a major thermal component. Its timing provides an accurate estimate for the spin of the primary black hole, ##IMG## [http://ej.iop.org/images/2041-8205/819/2/L37/apjl523055ieqn1.gif] $i =0.313pm 0.01$ . The present outburst also confirms the established general relativistic properties of the system such as the loss of orbital energy to gravitational radiation at the 2% accuracy level, and it opens up the possibility of testing the black hole no-hair theorem with 10% accuracy during the present decade.Peer reviewe