Intercomparison of general circulation models for hot extrasolar planets

We compare five general circulation models (GCMs) which have been recently used to study hot extrasolar planet atmospheres (BOB, CAM, IGCM, MITgcm, and PEQMOD), under three test cases useful for assessing model convergence and accuracy. Such a broad, detailed intercomparison has not been performed thus far for extrasolar planets study. The models considered all solve the traditional primitive equations, but employ di↵erent numerical algorithms or grids (e.g., pseudospectral and finite volume, with the latter separately in longitude-latitude and ‘cubed-sphere’ grids). The test cases are chosen to cleanly address specific aspects of the behaviors typically reported in hot extrasolar planet simulations: 1) steady-state, 2) nonlinearly evolving baroclinic wave, and 3) response to fast timescale thermal relaxation. When initialized with a steady jet, all models maintain the steadiness, as they should—except MITgcm in cubed-sphere grid. A very good agreement is obtained for a baroclinic wave evolving from an initial instability in pseudospectral models (only). However, exact numerical convergence is still not achieved across the pseudospectral models: amplitudes and phases are observably di↵erent. When subject to a typical ‘hot-Jupiter’-like forcing, all five models show quantitatively di↵erent behavior—although qualitatively similar, time-variable, quadrupole-dominated flows are produced. Hence, as have been advocated in several past studies, specific quantitative predictions (such as the location of large vortices and hot regions) by GCMs should be viewed with caution. Overall, in the tests considered here, pseudospectral models in pressure coordinate (PEBOB and PEQMOD) perform the best and MITgcm in cubed-sphere grid performs the worst

Search for dark matter in association with a Higgs boson decaying to b-quarks in pp collisions at √s=13 TeV with the ATLAS detector

A search for dark matter pair production in association with a Higgs boson decaying to a pair of bottom quarks is presented, using 3.2 fb−1of pp collisions at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the LHC. The decay of the Higgs boson is reconstructed as a high-momentum bb¯ system with either a pair of small-radius jets, or a single large-radius jet with substructure. The observed data are found to be consistent with the expected backgrounds. Results are interpreted using a simplified model with a Z′gauge boson mediating the interaction between dark matter and the Standard Model as well as a two-Higgs-doublet model containing an additional Z′boson which decays to a Standard Model Higgs boson and a new pseudoscalar Higgs boson, the latter decaying into a pair of dark matter particlesWe acknowledge the support of ANPCyT, Argentina; YerPhI, Ar-menia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbai-jan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Re-public; DNRF and DNSRC, Denmark; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, the Canada Council, CANARIE, CRC, Compute Canada, FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, FP7, Horizon 2020 and Marie Skłodowska-Curie Actions, opean Union; Investissements d’Avenir Labex and Idex, ANR, Région Au-vergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF; BSF, GIF and Minerva, Israel; BRF, Norway; Generalitat de Catalunya, Generalitat Valen-ciana, Spain; the Royal Society and Leverhulme Trust, United Kingdo

Evidence of an improper displacive phase transition in Cd2_2Re2_2O7_7 via time-resolved coherent phonon spectroscopy

We have used a combination of ultrafast coherent phonon spectroscopy, ultrafast thermometry, and time-dependent Landau theory to study the inversion symmetry breaking phase transition at $T_c = 200$ K in the strongly spin-orbit coupled correlated metal Cd$_2$Re$_2$O$_7$. We establish that the structural distortion at $T_c$ is a secondary effect through the absence of any softening of its associated phonon mode, which supports a purely electronically driven mechanism. However, the phonon lifetime exhibits an anomalously strong temperature dependence that decreases linearly to zero near $T_c$. We show that this behavior naturally explains the spurious appearance of phonon softening in previous Raman spectroscopy experiments and should be a prevalent feature of correlated electron systems with linearly coupled order parameters.Comment: 5 pages main text, 5 figures, 7 pages supplementary informatio

Momentum-resolved lattice dynamics of parent and electron-doped Sr2_{2}IrO4_{4}

The mixing of orbital and spin character in the wave functions of the $5d$ iridates has led to predictions of strong couplings among their lattice, electronic and magnetic degrees of freedom. As well as realizing a novel spin-orbit assisted Mott-insulating ground state, the perovskite iridate Sr$_{2}$IrO$_{4}$ has strong similarities with the cuprate La$_{2}$CuO$_{4}$, which on doping hosts a charge-density wave that appears intimately connected to high-temperature superconductivity. These phenomena can be sensitively probed through momentum-resolved measurements of the lattice dynamics, made possible by meV-resolution inelastic x-ray scattering. Here we report the first such measurements for both parent and electron-doped Sr$_{2}$IrO$_{4}$. We find that the low-energy phonon dispersions and intensities in both compounds are well described by the same nonmagnetic density functional theory calculation. In the parent compound, no changes of the phonons on magnetic ordering are discernible within the experimental resolution, and in the doped compound no anomalies are apparent due to charge-density waves. These measurements extend our knowledge of the lattice properties of (Sr$_{1-x}$La$_{x}$)$_{2}$IrO$_{4}$ and constrain the couplings of the phonons to magnetic and charge order.Comment: 8 pages, 6 figures (+ 12 pages, 6 figures of supplemental material

Parametric Forcing of Waves with Non-Monotonic Dispersion Relation: Domain Structures in Ferrofluids?

Surface waves on ferrofluids exposed to a dc-magnetic field exhibit a non-monotonic dispersion relation. The effect of a parametric driving on such waves is studied within suitable coupled Ginzburg-Landau equations. Due to the non-monotonicity the neutral curve for the excitation of standing waves can have up to three minima. The stability of the waves with respect to long-wave perturbations is determined $via$ a phase-diffusion equation. It shows that the band of stable wave numbers can split up into two or three sub-bands. The resulting competition between the wave numbers corresponding to the respective sub-bands leads quite naturally to patterns consisting of multiple domains of standing waves which differ in their wave number. The coarsening dynamics of such domain structures is addressed.Comment: 23 pages, 6 postscript figures, composed using RevTeX. Submitted to PR

Is the Rehbein procedure obsolete in the treatment of Hirschsprung’s disease?

Contains fulltext : 87916.pdf (publisher's version ) (Closed access)PURPOSE: After 25 years of practice and positive results of the Rehbein-procedure (RB) for children with Hirschsprung Disease (HD), we changed to the less invasive transanal endorectal pull through (TERPT). The aim of this study was to compare short- and mid-term complications of these two procedures in our patients with HD. METHODS: Retrospective data of 50 HD patients were analyzed. Of these patients, 25 underwent RB (2000-2006) and in 25 the TERPT was performed (2005-2009). Medical records were reviewed to score complications and outcomes. Differences were analyzed using Chi-Square and Mann-Whitney U tests. RESULTS: All RB patients (100%) were given a colostomy compared with four patients (16%) in the TERPT group (p < 0.001). The average age at surgery in the RB group was 191 days whereas this was 72 days in the TERPT group (p < 0.01). The mean length of time of surgery in the RB group (158 min) was not significantly different from that in the TERPT group (183 min). Ganglion cells were located in all specimens at the proximal end of the specimens. The median time to first feeding significantly decreased from 2 days (range 1-11) in the RB group to 1 day (range 1-3) in the TERPT group (p < 0.01). The median length of hospital stay decreased in the TERPT group (8 days) compared with the RB group (10 days) (p < 0.001). There was a significant reduction in postoperative obstructive symptoms during the first 6 months in the TERPT group (48%) compared with the RB group (84%) (p = 0.016). Postoperative enterocolitis decreased from 40% in the RB group to 24% in the TERPT group although this was not statistically significant. CONCLUSIONS: The introduction of TERPT reduced the need for colostomies; it shortened days to first feeding after surgery and reduced hospital stay. It also improved short-term outcome with less obstructive symptoms. We recommend TERPT surgery as a first choice in children with HD. we consider the RB now to be obsolete.1 november 201

Voltage controlled sub-THz detection with gated planar asymmetric nanochannels

[EN]This letter reports on room temperature sub-THz detection using self-switching diodes based on an AlGaN/GaN heterostructure on a Si substrate. By means of free-space measurements at 300 GHz, we demonstrate that the responsivity and noise equivalent power (NEP) of sub-THz detectors based on planar asymmetric nanochannels can be improved and voltage controlled by means of a top gate electrode. A simple quasi-static model based on the DC measurements of the current-voltage curves is able to predict the role of the gate bias in its performance. The best values of voltage responsivity and NEP are achieved when the gate bias approaches the threshold voltage, around 600 V/W and 50 pW/Hz1/2, respectively. A good agreement is found between modeled results and those obtained from RF measurements under probes at low frequency (900MHz) and in free-space at 300 GHz

A Survey of key methods, traits, parameters, and conditions for measuring texture in cranberry (Vaccinium macrocarpon Ait.)

In the cranberry (Vaccinium macrocarpon Ait.) industry, the textural properties and firmness of the fruit are priority traits for producing processed products, such as sweetened dried cranberry (SDC), which have gained popularity in recent years. However, there is currently no reliable methodology for screening these traits in breeding programs. In this study, we examine the key methodologies, textural traits, parameters, and conditions that are necessary to accurately and efficiently measure the texture of cranberry fruit. Double compression, single compression, puncture, shearing and Kramer shear cell methodologies were successfully implemented in cranberry, resulting in a total of 47 textural features. These features allowed the evaluation of the texture of the cranberry fruit based on key factors such as flesh, structure, and skin. This study also examined factors than can affect the performance of texture measurements, including the optimal sample size, storage time, fruit texture-size correlation, fruit temperature and orientation, optimal speed/strain combinations, and the effect of probe diameter. The results of the study suggests that certain texture traits of the compression and puncture methodologies could potentially be used to test varieties and aid in breeding program

Momentum-independent magnetic excitation continuum in the honeycomb iridate H3_3LiIr2_2O6_6

In the search for realizations of Quantum Spin Liquids (QSL), it is essential to understand the interplay between inherent disorder and the correlated fluctuating spin ground state. H$_3$LiIr$_2$O$_6$ is regarded as a spin liquid proximate to the Kitaev-limit (KQSL) in which H zero-point motion and stacking faults are known to be present. Bond disorder has been invoked to account for the existence of unexpected low-energy spin excitations. Controversy remains about the nature of the underlying correlated state and if any KQSL physics survives. Here, we use resonant X-ray spectroscopies to map the collective excitations in H$_3$LiIr$_2$O$_6$ and characterize its magnetic state. We uncover a broad bandwidth and momentum-independent continuum of magnetic excitations at low temperatures that are distinct from the paramagnetic state. The center energy and high-energy tail of the continuum are consistent with expectations for dominant ferromagnetic Kitaev interactions between dynamically fluctuating spins. The absence of a momentum dependence to these excitations indicates a broken translational invariance. Our data support an interpretation of H$_3$LiIr$_2$O$_6$ as a disordered topological spin liquid in close proximity to bond-disordered versions of the KQSL. Our results shed light on how random disorder affects topological magnetic states and have implications for future experimental and theoretical works toward realizing the Kitaev model in condensed matter system

Many-particle Brownian and Langevin Dynamics Simulations with the Brownmove package

<p>Abstract</p> <p>Background</p> <p>Brownian Dynamics (BD) is a coarse-grained implicit-solvent simulation method that is routinely used to investigate binary protein association dynamics, but due to its efficiency in handling large simulation volumes and particle numbers it is well suited to also describe many-protein scenarios as they often occur in biological cells.</p> <p>Results</p> <p>Here we introduce our "brownmove" simulation package which was designed to handle many-particle problems with varying particle numbers and allows for a very flexible definition of rigid and flexible protein and polymer models. Both a Brownian and a Langevin dynamics (LD) propagation scheme can be used and hydrodynamic interactions are treated efficiently with our recently introduced TEA-HI ansatz [Geyer, Winter, JCP 130 (2009) 114905]. With simulations of constrained polymers and flexible models of spherical proteins we demonstrate that it is crucial to include hydrodynamics when multi-bead models are used in BD or LD simulations. Only then both the translational and the rotational diffusion coefficients and the timescales of the internal dynamics can be reproduced correctly. In the third example project we show how constant density boundary conditions [Geyer et al, JCP 120 (2004) 4573] can be used to set up a non-equilibrium simulation of diffusional transport across an array of fixed obstacles. Finally, we demonstrate how the agglomeration dynamics of multiple particles with attractive patches can be analysed conveniently with the help of a dynamic interaction network.</p> <p>Conclusions</p> <p>Combining BD and LD propagation, fast hydrodynamics, a flexible protein model, and interfaces for "open" simulation settings, our freely available "brownmove" simulation package constitutes a new platform for coarse-grained many-particle simulations of biologically relevant diffusion and transport processes.</p