Quantum Isometries of the finite noncommutative geometry of the Standard Model

We compute the quantum isometry group of the finite noncommutative geometry F describing the internal degrees of freedom in the Standard Model of particle physics. We show that this provides genuine quantum symmetries of the spectral triple corresponding to M x F where M is a compact spin manifold. We also prove that the bosonic and fermionic part of the spectral action are preserved by these symmetries.Comment: 29 pages, no figures v3: minor change

Direct numerical simulation of a warm cloud top model interface: Impact of the transient mixing on different droplet population

Turbulent mixing through atmospheric cloud and clear air interface plays an important role in the life of a cloud. Entrainment and detrainment of clear air and cloudy volume result in mixing across the interface, which broadens the cloud droplet spectrum. In this study, we simulate the transient evolution of a turbulent cloud top interface with three initial mono-disperse cloud droplet population, using a pseudo-spectral Direct Numerical Simulation (DNS) along with Lagrangian droplet equations, including collision and coalescence. Transient evolution of in-cloud turbulent kinetic energy (TKE), density of water vapour and temperature is carried out as an initial value problem exhibiting transient decay. Mixing in between the clear air and cloudy volume produced turbulent fluctuations in the density of water vapour and temperature, resulting in supersaturation fluctuations. Small scale turbulence, local supersaturation conditions and gravitational forces have different weights on the droplet population depending on their sizes. Larger droplet populations, with initial 25 and 18 μm radii, show significant growth by droplet-droplet collision and a higher rate of gravitational sedimentation. However, the smaller droplets, with an initial 6 μm radius, did not show any collision but a large size distribution broadening due to differential condensation/evaporation induced by the mixing, without being influenced by gravity significantly

Transient evolution of warm cloud - clear air interface and its impact on cloud droplet evolution

Three dimensional Direct Numerical Simulation (DNS) using pseudo-spectral Fourier Galerkin method is used for simulating Warm Cloud – Clear Air interfaces [1,2]. Transient evolution of transport of energy, water vapour, temperature and Lagrangian tracking of droplets are simulated for decaying turbulent atmospheric flow, where initial turbulent kinetic energy (TKE) in the simulation domain decays with time [1,2]. Simulation results shows anisotropy and high intermittency across the interface (from high TKE region of cloud side to low TKE region of clear air side), which influenced the transient evolution of passive scalar transport [3]. Cloud droplets are observed to be affected by the small scale turbulence, and they preferentially concentrated away from the regions of high vorticity. Transient evolution of various microphysical properties, such as, droplet sedimentation, condensation/evaporation, droplet inertia, droplet collision and coalescence are investigated to understand the role of turbulence in interfacial transient. Supersaturation and preferential concentration resulted in condensational growth of the droplets and increased local droplet collision rate. As a result, droplet size distribution grew with time, in contrary to the saturated case (Fig 1

Expression of virulence genes in luminescent and nonluminescent isogenic vibrios and virulence towards gnotobiotic brine shrimp (<i>Artemia franciscana</i>)

Aims: This study aimed to evaluate the expression levels of virulence gene regulators (luxR and toxR) and virulence factors (serine protease, metalloprotease and haemolysin) in luminescent and nonluminescent isogenic Vibrio harveyi and Vibrio campbellii.Method and Results: Nonluminescent variants have been reported before to become dominant in cultures of luminescent vibrios when grown under static conditions in the dark. Wild-type V. harveyi BB120, V. campbellii LMG 21363, quorum sensing mutants of V. harveyi BB120 and their previously reported nonluminescent isogenic counterparts were used in this study. The expression level of the virulence genes srp serine protease, vhp metalloprotease and vhh haemolysin, the quorum sensing master regulator gene luxR and the virulence regulator gene toxR in isogenic luminescent and nonluminescent strains were quantified using reverse transcriptase real-time PCR. These experiments revealed that the nonluminescent strains produced lower levels of the quorum sensing master regulator gene luxR and the vhp metalloprotease gene (which is known to be regulated by quorum sensing). Finally, challenge tests with gnotobiotic brine shrimp (Artemia franciscana) larvae revealed that the nonluminescent strains are less virulent than their luminescent isogenic counterparts.Conclusion: Nonluminescent variants of V. harveyi and V. campbellii strains produce lower levels of the quorum sensing master regulator gene luxR and the vhp metalloprotease gene and are less virulent to brine shrimp than their isogenic luminescent counterparts.Significance and Impact of the study: These results indicate that adaptation of luminescent vibrios to specific growth conditions that result in a dominant nonluminescent phenotype is accompanied by a decreased adaptation to a host environment because of altered virulence gene regulation

The evolution of galaxy intrinsic alignments in the MassiveBlackII universe

We investigate the redshift evolution of the intrinsic alignments (IAs) of galaxies in the MassiveBlackII (MBII) simulation. We select galaxy samples above fixed subhalo mass cuts (⁠Mh>1011,12,13M⊙h−1⁠) at z = 0.6 and trace their progenitors to z = 3 along their merger trees. Dark matter components of z = 0.6 galaxies are more spherical than their progenitors while stellar matter components tend to be less spherical than their progenitors. The distribution of the galaxy–subhalo misalignment angle peaks at ∼10 deg with a mild increase with time. The evolution of the ellipticity–direction (ED) correlation amplitude ω(r) of galaxies (which quantifies the tendency of galaxies to preferentially point towards surrounding matter overdensities) is governed by the evolution in the alignment of underlying dark matter (DM) subhaloes to the matter density of field, as well as the alignment between galaxies and their DM subhaloes. At scales ∼1 Mpch−1⁠, the alignment between DM subhaloes and matter overdensity gets suppressed with time, whereas the alignment between galaxies and DM subhaloes is enhanced. These competing tendencies lead to a complex redshift evolution of ω(r) for galaxies at ∼1 Mpch−1⁠. At scales >1 Mpch−1⁠, alignment between DM subhaloes and matter overdensity does not evolve significantly; the evolution of the galaxy–subhalo misalignment therefore leads to an increase in ω(r) for galaxies by a factor of ∼4 from z = 3 to 0.6 at scales >1 Mpch−1⁠. The balance between competing physical effects is scale dependent, leading to different conclusions at much smaller scales (⁠∼0.1 Mpch−1⁠)

Quantum isometries and noncommutative spheres

We introduce and study two new examples of noncommutative spheres: the half-liberated sphere, and the free sphere. Together with the usual sphere, these two spheres have the property that the corresponding quantum isometry group is "easy", in the representation theory sense. We present as well some general comments on the axiomatization problem, and on the "untwisted" and "non-easy" case.Comment: 16 page

Cosmic variance of z > 7 galaxies: prediction from BLUETIDES

In the coming decade, a new generation of telescopes, including JWST and WFIRST, will probe the period of the formation of first galaxies and quasars, and open up the last frontier for structure formation. Recent simulations and observations have suggested that these galaxies are strongly clustered (with large-scale bias 6), and therefore have significant cosmic variance. In this work, we use BLUETIDES, the largest volume cosmological simulation of galaxy formation, to directly estimate the cosmic variance for current and upcoming surveys. Given its resolution and volume, BLUETIDES can probe the bias and cosmic variance of z > 7 galaxies between magnitude MUV ∼ −16 and MUV ∼ −22 over survey areas ∼0.1 arcmin2 to ∼10 deg2. Within this regime, the cosmic variance decreases with survey area/ volume as a power law with exponents between ∼−0.25 and ∼−0.45. For the planned 10 deg2 field of WFIRST, the\ud cosmic variance is between 3 per cent and 10 per cent. Upcoming JWST medium/ deep surveys with areas up to A ∼ 100 arcmin2 will have cosmic variance ranging from ∼20 to 50 per cent. Lensed surveys have the highest cosmic variance 40 per cent; the cosmic variance of MUV −16 galaxies is 100 per cent up to z ∼ 11. At higher redshifts such as z ∼ 12 (14), effective volumes of (8 Mpc h−1) 3 ((12 Mpc h−1) 3) are required to limit the cosmic variance to within 100 per cent. Finally, we find that cosmic variance is larger than Poisson variance and forms the dominant component of the overall uncertainty in all current and upcoming surveys. We present our calculations in the form of simple fitting functions and an online cosmic variance calculator (CV AT COSMIC DAWN) that we publicly release

Incompressibility of strange matter

Strange stars calculated from a realistic equation of state (EOS), that incorporate chiral symmetry restoration as well as deconfinement at high density show compact objects in the mass radius curve. We compare our calculations of incompressibility for this EOS with that of nuclear matter. One of the nuclear matter EOS has a continuous transition to ud-matter at about five times normal density. Another nuclear matter EOS incorporates density dependent coupling constants. From a look at the consequent velocity of sound, it is found that the transition to ud-matter seems necessary.Comment: Accepted for publication in Phys Lett

Evaluation of Important Treatment Parameters in Supraphysiological Thermal Therapy of Human Liver Cancer HepG2 Cells

This study was aimed at simulating the effect of various treatment parameters like heating rate (HR), peak temperature (PT) and hold/total treatment time on the viability of human liver cancer HepG2 cells subjected to different thermal therapy conditions. The problem was approached by investigating the injury kinetics obtained using experimentally measured viability of the cells, heated to temperatures of 50–70°C for 0–9 min at HRs of 100, 200, 300 and 525°C min(−1). An empirical expression obtained between the activation energy (E) and HR was extended to obtain the E values over a broad range of HRs from 5 to 600°C min(−1) that mimic the actual conditions encountered in a typical thermal therapy protocol. Further, the effect of the HR (5–600°C min(−1)) and PT (50–85°C) on the cell survival was studied over a range of hold times. A significant drop in survival from 90% to 0% with the simultaneous increase in HR and PT was observed as the hold time increased from 0 to 5 min. For complete cell death, the hold time increased with the increase in the HR for a given PT, while the total time showed presence of minima for 60, 65 and 70°C at HRs of 50, 100 and 200°C min(−1), respectively