595 research outputs found
Family practices and temporality at breakfast: hot spots, convenience and care
Drawing on 34 semi-structured interviews, this study investigates the temporality of family practices taking place in the hot spot (Southerton, 2003). It does so by looking at how breakfast is inserted in the economy of family time in Italy. Our data show that breakfast, contrary to other meals, allows the adoption of more individualised and asynchronous practices, hinged on the consumption of convenience products. These time-saving strategies are normalised as part of doing family. Although the existing literature suggests that convenience and care are in opposition, and consumers of convenience products can experience anxiety and a lack of personal integrity, such features were not a dominant feature of our participants’ accounts. These findings suggest that the dichotomies of hot/cold spots and care/convenience are not always experienced in opposition when embedded within family practices. Hence, this study furthers understandings of family meals, temporality and the distinction between hot and cold spots
USE OF GASEOUS OZONE AS A DISINFECTANT IN MEAT INDUSTRY
The aim of this study was to investigate the possible use of gaseous ozone as a disinfectant for meat industry environments. Firstly microbial inactivation trials were conducted in laboratory conditions on Petri plates inoculated with some microorganisms of importance to the food industry. The treatment with 1 ppm of ozone resulted to be effective in 1 h on the strains in use. Then similar trials were conducted in a meat industry, 1 ppm of ozone was supplied for 3 h. The results confirmed the antimicrobial efficacy of ozone even if it was less active than in laboratory conditions. A different sensibility among the microorganisms was observed, the most resistant being P. fluorescens and B. thuringiensis. Our results confirm the suitability of gaseous ozone as a disinfectant for meat industry environments and underline the need to calibrate ozone treatment parameters on the real environmental conditions of work-room
Methane-Rare Gas Interaction Potentials from Scattering Experiments
By using total differential cross sections with resolved diffraction oscillations and absolute integral cross sections with glory oscillations, a new improved spherically averaged potential surface for Ne-CH4 is determined with a potential well depth of ε = 5.50 meV and a minimum distance of Rm = 3.78 Å. A slightly improved parameter set is also given for the isotropic Ar-CH4 interaction. By assuming the same realistic reduced potential form as was found for Ne-CH4 and Ar-CH4, the isotropic parts of the potential for Kr-CH4 and Xe-CH4 are obtained from absolute integral cross sections
Phylogeny of helieae (gentianaceae): resolving taxonomic chaos in a neotropical clade
The monophyletic and Neotropical tribe Helieae of the worldwide family Gentianaceae (Gentianales, Asterids, Angiospermae) is well known for its problematic generic classifications. An initial phylogenetic analysis of Helieae shed light onto the relationships between genera, and indicated that traditional generic limits did not correspond to monophyletic groups. In order to obtain a more thorough understanding of generic relationships within the group, we enhanced sampling within the so-called Symbolanthus clade and performed phylogenetic analyses from DNA sequences from one plastid region (matK) and two nuclear regions (ITS and 5S-NTS), plus 112 morphological characters, which were analyzed separately and in combination, using parsimony and Bayesian approaches. A total of 83 individuals representing 20 genera and 51 species of Helieae were sampled; 13 species were included in this study solely based on their morphological characters. Ancestral character reconstructions were performed to identify potential synapomorphies of clades and patterns of homoplasy in the morphological dataset. Our results demonstrate that Prepusa is sister to the remainder of Helieae. Furthermore, the Macrocarpaea clade, the Irlbachia clade and the Symbolanthus clade were also recovered. Within the Symbolanthus clade, our results confirm that Calolisianthus and Chelonanthus are not monophyletic, and also contest the monophyly of Irlbachia as currently circumscribed. Specifically, two species of Calolisianthus group with the type species of Chelonanthus, while the other Calolisianthus species are more closely related to Tetrapollinia and Symbolanthus. Moreover, the green-white-flowered Chelonanthus species and Adenolisianthus are undoubtedly related to Helia and several analyses support Irlbachia pratensis as more closely related to the lineage including the type species of Chelonanthus described above The addition of new characters and taxa led to higher confidence in the relative position of some clades, as well as provided further support for a new generic circumscription of Calolisianthus, Chelonanthus, and Helia. Even though several morphological characters traditionally used in the taxonomy of the group were shown to be homoplasious, most clades can be diagnosed by a combination of morphological character states10619220
Parallel-propagated frame along null geodesics in higher-dimensional black hole spacetimes
In [arXiv:0803.3259] the equations describing the parallel transport of
orthonormal frames along timelike (spacelike) geodesics in a spacetime
admitting a non-degenerate principal conformal Killing-Yano 2-form h were
solved. The construction employed is based on studying the Darboux subspaces of
the 2-form F obtained as a projection of h along the geodesic trajectory. In
this paper we demonstrate that, although slightly modified, a similar
construction is possible also in the case of null geodesics. In particular, we
explicitly construct the parallel-transported frames along null geodesics in
D=4,5,6 Kerr-NUT-(A)dS spacetimes. We further discuss the parallel transport
along principal null directions in these spacetimes. Such directions coincide
with the eigenvectors of the principal conformal Killing-Yano tensor. Finally,
we show how to obtain a parallel-transported frame along null geodesics in the
background of the 4D Plebanski-Demianski metric which admits only a conformal
generalization of the Killing-Yano tensor.Comment: 17 pages, no figure
Equilibrium conditions of spinning test particles in Kerr-de Sitter spacetimes
Equilibrium conditions and spin dynamics of spinning test particles are
discussed in the stationary and axially symmetric Kerr-de Sitter black-hole or
naked-singularity spacetimes. The general equilibrium conditions are
established, but due to their great complexity, the detailed discussion of the
equilibrium conditions and spin dynamics is presented only in the simple and
most relevant cases of equilibrium positions in the equatorial plane and on the
symmetry axis of the spacetimes. It is shown that due to the combined effect of
the rotation of the source and the cosmic repulsion the equilibrium is spin
dependent in contrast to the spherically symmetric spacetimes. In the
equatorial plane, it is possible at the so-called static radius, where the
gravitational attraction is balanced by the cosmic repulsion, for the spinless
particles as well as for spinning particles with arbitrarily large
azimuthal-oriented spin or at any radius outside the ergosphere with a
specifically given spin orthogonal to the equatorial plane. On the symmetry
axis, the equilibrium is possible at any radius in the stationary region and is
given by an appropriately tuned spin directed along the axis. At the static
radii on the axis the spin of particles in equilibrium must vanish
Benefit of woodland and other natural environments for adolescents’ cognition and mental health
Epidemiological studies have established positive associations of urban nature with cognitive development and mental health. However, why specifically these health benefits are received remains unclear, especially in adolescents. We used longitudinal data in a cohort of 3,568 adolescents aged 9 to 15 years at 31 schools across London, UK, to examine the associations between natural-environment types and adolescents’ cognitive development, mental health and overall well-being. We characterized natural-environment types in three tiers, where natural space was distinguished into green and blue space, and green space was further distinguished into woodland and grassland. We showed that, after adjusting for other confounding variables, higher daily exposure to woodland, but not grassland, was associated with higher scores for cognitive development and a lower risk of emotional and behavioural problems for adolescents. A similar but smaller effect was seen for green space, but not blue space, with higher scores for cognitive development. Our results suggest that urban planning decisions to optimize ecosystem benefits linked to cognitive development and mental health should carefully consider the type of natural environment included
Geodesic Deviation Equation in Bianchi Cosmologies
We present the Geodesic Deviation Equation (GDE) for the
Friedmann-Robertson-Walker(FRW) universe and we compare it with the equation
for Bianchi type I model. We justify consider this cosmological model due to
the recent importance the Bianchi Models have as alternative models in
cosmology. The main property of these models, solutions of Einstein Field
Equations (EFE) is that they are homogeneous as the FRW model but they are not
isotropic. We can see this because they have a non-null Weyl tensor in the GDE.Comment: Submitted to Journal of Physics: Conference Series (JPCS), ERE200
Gyroscope deviation from geodesic motion: quasiresonant oscillations on a circular orbit
General relativistic spin-orbit interaction leads to the quasiresonant
oscillation of the gyroscope mass center along the orbital normal. The beating
amplitude does not include the speed of light and equals the ratio of the
intrinsic momentum of the gyroscope to its orbital momentum. The modulation
frequency equals the angular velocity of the geodetic precession that prevents
the oscillation from resonance. The oscillation represents the precession of
the gyroscope orbital momentum. Within an acceptable time the oscillation
amplitude reaches the values that are amenable to being analyzed
experimentally. Taking into account the source oblateness decreases the beating
amplitude and increases the modulation frequency by the factor that is equal to
the ratio of the quadrupole precession velocity to the geodetic precession
velocity. The period of the quadrupole precession turns out to be a quite
sufficient time to form a measurable amplitude of the oscillation.Comment: 5 pages, LaTeX2e, 1 eps figure, to appear in J. Exp. Theor. Phy
The spacetime structure of MOND with Tully-Fisher relation and Lorentz invariance violation
It is believed that the modification of Newtonian dynamics (MOND) is possible
alternate for dark matter hypothesis. Although Bekenstein's TeVeS supplies a
relativistic version of MOND, one may still wish a more concise covariant
formulism of MOND. In this paper, within covariant geometrical framwork, we
present another version of MOND. We show the spacetime structure of MOND with
properties of Tully-Fisher relation and Lorentz invariance violation.Comment: 6 pages. arXiv admin note: substantial text overlap with
arXiv:1111.1383 and arXiv:1108.344
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