Stringent constraint on the scalar-neutrino coupling constant from quintessential cosmology

An extremely light ($m_{\phi} \ll 10^{-33} {\rm eV}$), slowly-varying scalar field $\phi$ (quintessence) with a potential energy density as large as 60% of the critical density has been proposed as the origin of the accelerated expansion of the Universe at present. The interaction of this smoothly distributed component with another predominately smooth component, the cosmic neutrino background, is studied. The slow-roll approximation for generic $\phi$ potentials may then be used to obtain a limit on the scalar-neutrino coupling constant, found to be many orders of magnitude more stringent than the limits set by observations of neutrinos from SN 1987A. In addition, if quintessential theory allows for a violation of the equivalence principle in the sector of neutrinos, the current solar neutrino data can probe such a violation at the 10^{-10} level.Comment: 7 pages, MPLA in press, some parts disregarded and a footnote adde

Quark number scaling in fluid dynamics and hadronization via quarkyonic matter

NCQ scaling of elliptic flow is studied in a non-equilibrium hadronization and freeze-out model from ideal, deconfined and chirally symmetric Quark Gluon Plasma (QGP), to final non-interacting hadrons. In this transition the quarks gain constituent quark mass while the background Bag-field breaks up. The constituent quarks then recombine into simplified hadron states, while chemical, thermal and flow equilibrium break down. Then the resulting temperatures and flow velocities of baryons and mesons will be different. In a simplified model, we reproduce the constituent quark number scaling

UTJECAJ DUŽINE TRANSPORTA I MIJEŠANJA GRUPA NA KAKVOĆU JUNEĆIH TRUPOVA SIMENTALSKIH BIKOVA

In the last few years, beef producers have had great problems with beef distribution, related primarily to the frequent incidence of dark, firm, dry meat. Consumers are unlikely to buy and consume such meat. The aim of this study was to examine the effect of transport period and mixing of groups during rest period in lairage on the quality of beef carcasses. The study included 40 Simmental bulls aged from 18 to 20 months. Ultimate pH value and meat colour were measured 24 hours post mortem in m. longissimus dorsi and m. gracilis. Only 45% of carcasses were within the standard pHu range. Results of transport period did not show significant effect on beef quality. In contrast to transport period, mixing of groups during rest period in lairage had highly significant adverse effect on beef quality (p<0.001). The effect of mixing of bulls during the resting period of 18 hours, could however be regarded of being the main stress factor.Proizvođači junećega mesa proteklih godina imaju značajne probleme u plasmanu junetine, prvenstveno zbog učestalije pojave tamnog suhog i tvrdog mesa (DFD). Potrošači takvo meso nerado kupuju i konzumiraju. Cilj ovog istraživanja je utvrditi značajnost utjecaja dužine transporta i miješanja grupa bikova tijekom odmora u stočnom depou na kakvoću junećih trupova. Istraživanje je uključilo 40 simentalske junadi u dobi od 18 do 20 mjeseci. Mjerenje konačne pH vrijednosti i boje mesa vršena su 24 sata post mortem na m. longissimus dorsi i m. gracilis. Samo je 45% trupova imalo vrijednost kpH u poželjnom intervalu. Istraživanjem nije utvrđen značajan utjecaj dužine transporta na pokazatelje kakvoće junećih trupova. Miješanje grupa bikova tijekom odmora u stočnom depou ima značajan utjecaj na kakvoću junećih trupova (p<0.001). Utjecaj miješanja grupa bikova tijekom odmora u stočnom može se smatrati jednim od glavnih uzročnika stresa odgovornog za pojavu DFD junećega mesa

UTJECAJ DUŽINE TRANSPORTA I MIJEŠANJA GRUPA NA KAKVOĆU JUNEĆIH TRUPOVA SIMENTALSKIH BIKOVA

In the last few years, beef producers have had great problems with beef distribution, related primarily to the frequent incidence of dark, firm, dry meat. Consumers are unlikely to buy and consume such meat. The aim of this study was to examine the effect of transport period and mixing of groups during rest period in lairage on the quality of beef carcasses. The study included 40 Simmental bulls aged from 18 to 20 months. Ultimate pH value and meat colour were measured 24 hours post mortem in m. longissimus dorsi and m. gracilis. Only 45% of carcasses were within the standard pHu range. Results of transport period did not show significant effect on beef quality. In contrast to transport period, mixing of groups during rest period in lairage had highly significant adverse effect on beef quality (p<0.001). The effect of mixing of bulls during the resting period of 18 hours, could however be regarded of being the main stress factor.Proizvođači junećega mesa proteklih godina imaju značajne probleme u plasmanu junetine, prvenstveno zbog učestalije pojave tamnog suhog i tvrdog mesa (DFD). Potrošači takvo meso nerado kupuju i konzumiraju. Cilj ovog istraživanja je utvrditi značajnost utjecaja dužine transporta i miješanja grupa bikova tijekom odmora u stočnom depou na kakvoću junećih trupova. Istraživanje je uključilo 40 simentalske junadi u dobi od 18 do 20 mjeseci. Mjerenje konačne pH vrijednosti i boje mesa vršena su 24 sata post mortem na m. longissimus dorsi i m. gracilis. Samo je 45% trupova imalo vrijednost kpH u poželjnom intervalu. Istraživanjem nije utvrđen značajan utjecaj dužine transporta na pokazatelje kakvoće junećih trupova. Miješanje grupa bikova tijekom odmora u stočnom depou ima značajan utjecaj na kakvoću junećih trupova (p<0.001). Utjecaj miješanja grupa bikova tijekom odmora u stočnom može se smatrati jednim od glavnih uzročnika stresa odgovornog za pojavu DFD junećega mesa

Dynamical approach to chains of scatterers

Linear chains of quantum scatterers are studied in the process of lengthening, which is treated and analysed as a discrete dynamical system defined over the manifold of scattering matrices. Elementary properties of such dynamics relate the transport through the chain to the spectral properties of individual scatterers. For a single-scattering channel case some new light is shed on known transport properties of disordered and noisy chains, whereas translationally invariant case can be studied analytically in terms of a simple deterministic dynamical map. The many-channel case was studied numerically by examining the statistical properties of scatterers that correspond to a certain type of transport of the chain i.e. ballistic or (partially) localised.Comment: 16 pages, 7 figure

Radial stability analysis of the continuous pressure gravastar

Radial stability of the continuous pressure gravastar is studied using the conventional Chandrasekhar method. The equation of state for the static gravastar solutions is derived and Einstein equations for small perturbations around the equilibrium are solved as an eigenvalue problem for radial pulsations. Within the model there exist a set of parameters leading to a stable fundamental mode, thus proving radial stability of the continuous pressure gravastar. It is also shown that the central energy density possesses an extremum in rho_c(R) curve which represents a splitting point between stable and unstable gravastar configurations. As such the rho_c(R) curve for the gravastar mimics the famous M(R) curve for a polytrope. Together with the former axial stability calculations this work completes the stability problem of the continuous pressure gravastar.Comment: 17 pages, 5 figures, References corrected, minor changes wrt v1, matches published versio

An assessment of scale-dependent variability and bias in global prediction models

The paper presents a method for the scale-dependent validation of the spatio-temporal variability in global weather or climate models and for their bias quantification in relation to dynamics. The method provides a relationship between the bias and simulated spatial and temporal variance by a model in comparison with verifying reanalysis data. For the low resolution (T30L8) subset of ERA-20C data, it was found that 80–90 (depending on season) of the global interannual variance is at planetary scales (zonal wavenumbers k = 0−3), and only about 1 of the variance is at scales with k> 7. The reanalysis is used to validate a T30L8 GCM in two configurations, one with the prescribed sea-surface temperature (SST) and another using a slab ocean model. Although the model with the prescribed SST represents the average properties of surface fields well, the interannual variability is underestimated at all scales. Similar to variability, model bias is strongly scale dependent. Biases found in the experiment with the prescribed SST are largely increased in the experiment using a slab ocean, especially in k= 0 , in scales with missing variability and in seasons with poorly simulated energy distribution. The perfect model scenario (a comparison between the GCM coupled to a slab ocean vs. the same model with prescribed SSTs) shows that the representation of the ocean is not critical for synoptic to subsynoptic variability, but essential for capturing the planetary scales. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature

Speed of Sound in the Mass Varying Neutrinos Scenario

We discuss about the speed of sound squared in the Mass Varying Neutrinos scenario (MaVaNs). Recently, it was argued that the MaVaNs has a catastrophic instability which is the emergence of an imaginary speed of sound at the non-relativistic limit of neutrinos. As the result of this instability, the neutrino-acceleron fluid cannot act as the dark energy. However, it is found that the speed of sound squared in the neutrino-acceleron fluid could be positive in our model. We examine the speed of sound in two cases of the scalar potential. One is the small fractional power-law potential and another is the logarithmic one. The power-law potential model with the right-handed neutrinos gives a stable one.Comment: 17 pages, References added, minor modification