11,845 research outputs found
A torsional completion of gravity for Dirac matter fields and its applications to neutrino oscillations
In this paper, we consider the torsional completion of gravitation for an
underlying background filled with Dirac fields, applying it to the problem of
neutrino oscillations: we discuss the effects of the induced torsional
interactions as corrections to the neutrino oscillation mechanism.Comment: 4 page
Analyses of rare collection samples as conservation tool for the last known Italian population of Graphoderus bilineatus (Insecta: Coleoptera)
Graphoderus bilineatus is a predacious diving beetle, widely distributed across Europe. Its poor dispersal ability and the fragmentation and deterioration of its habitats have been indicated as the major causes of decline. In several western European countries, the species is extinct, justifying its inclusion as "vulnerable" in the IUCN red list. Aiming for the conservation of the last known population of G. bilineatus in the northern Italian region of Emilia Romagna, at the lake Pratignano, we surveyed its genetic diversity at the mitochondrial COI gene and compared it to that of other European populations. Two fixed COI haplotypes were found in the Italian and Austrian populations, respectively. Both haplotypes were unique among the European populations surveyed, suggesting these populations suffered a bottleneck and geographic isolation. Populations in western Europe showed lower genetic diversity and higher degree of differentiation than eastern populations. The uniqueness of Pratignano haplotype makes it difficult to choose a source population from which to transfer animals for a possible restocking. Selection of the source population should be based mainly on ecological considerations, but at the same time ensuring a good genetic diversity to maximize the adaptive potential
A Novel Approach for an Integrated Straw tube-Microstrip Detector
We report on a novel concept of silicon microstrips and straw tubes detector,
where integration is accomplished by a straw module with straws not subjected
to mechanical tension in a Rohacell lattice and carbon fiber
reinforced plastic shell. Results on mechanical and test beam performances are
reported on as well.Comment: Accepted by Transactions on Nuclear Science (2005). 11 pages, 9
figures, uses lnfprep.st
Resolving the M2-brane
We construct deformed, T^2 wrapped, rotating M2-branes on a resolved cone
over Q^{1,1,1} and Q^{1,1,1}/Z_2, as well as on a product of two Eguchi-Hanson
instantons. All worldvolume directions of these supersymmetric and regular
solutions are fibred over the transverse space. These constitute gravity duals
of D=3, N=2 gauge theories. In particular, the deformed M2-brane on a resolved
cone over Q^{1,1,1} and the S^1 wrapped M2-brane on a resolved cone over
Q^{1,1,1}/Z_2 provide explicit realizations of holographic renormalization
group flows in M-theory for which both conformal and Lorentz symmetries are
broken in the IR region and restored in the UV limit. These solutions can be
dualized to supersymmetric type IIB pp-waves, which are rendered non-singular
either by additional flux or a twisted time-like direction.Comment: Latex, 23 pages, references adde
On the trail of medieval wolves: ancient DNA, CT-based analyses and palaeopathology of a 1000-year-old wolf cranium from the Po Valley (northern Italy)
The Middle Ages represented a crucial period for the evolutionary history of wolves (Canis lupus), marked by both significant ecosystem changes, especially through the degradation of wooded landscapes and heavy persecution, that drove this species to a dramatic demographic decline. In Europe, informative and well-documented wolf remains from the Medieval Ages are exceptionally rare and are mostly represented by teeth and postcranial elements. In this study, we describe a well-preserved wolf cranium dated to ca. 967–1157 AD from the Po Valley (northern Italy). The specimen was analysed through a multidisciplinary approach including CT-based, ancient DNA, and palaeopathological analyses. Morphological and genetic data supported the assignment of this sample to Canis lupus species. CT-based analyses indicated a typical wolf-like morphology falling into the extant variability of the medium-sized subspecies C. lupus italicus, whereas palaeopathological analyses indicated a severe periodontitis. Phylogenetic analyses showed that the Po valley wolf had a unique and never described mtDNA control region haplotype, testifying variability in the ancient Italian wolf, which has now been lost. This study provides the first comprehensive description of a wolf from the Middle Ages, adding useful information for a deeper knowledge about population dynamics, variability, and diseases of this species
Spirometry: A practical lifespan predictor of global health and chronic respiratory and non-respiratory diseases
Objectives. 1. To review and discuss available evidence supporting that spirometry is an overlooked global health marker, that could be used regularly through the lifespan to monitor human health and predict risk of chronic respiratory and other chronic non-communicable diseases (NCDs). 2. To discuss the challenges and opportunities that this proposal faces.Summary of key data. First, spirometry is essential to assess and monitor respiratory health. Second, spirometry adds prognostic value to other well-accepted health markers used in clinical practice, such as blood pressure, body mass index, glucose and blood lipids, by identifying individuals at risk, not only of respiratory diseases, but also of other NCDs, particularly cardiovascular and metabolic disorders. Conclusion. Although we acknowledge that research gaps still exist, we propose that spirometry assessed during childhood, adolescence and early and late adulthood can be a reproducible, non-invasive, safe and affordable global health marker to identify individuals in the general population at risk of respiratory and non-respiratory NCDs. In this context, spirometry may act as the caged canaries that miners used to carry into mines to alert them of dangerous accumulations of gases, thus providing an early warning and save lives
SN 2007od: A Type IIP SN with Circumstellar Interaction
SN 2007od exhibits characteristics that have rarely been seen in a Type IIP
supernova (SN). Optical V band photometry reveals a very steep brightness
decline between the plateau and nebular phases of ~4.5 mag, likely due to SN
2007od containing a low mass of 56Ni. The optical spectra show an evolution
from normal Type IIP with broad Halpha emission, to a complex, four component
Halpha emission profile exhibiting asymmetries caused by dust extinction after
day 232. This is similar to the spectral evolution of the Type IIn SN 1998S,
although no early-time narrow (~200 km s-1) Halpha component was present in SN
2007od. In both SNe, the intermediate-width Halpha emission components are
thought to arise in the interaction between the ejecta and its circumstellar
medium (CSM). SN 2007od also shows a mid-IR excess due to new dust. The
evolution of the Halpha profile and the presence of the mid-IR excess provide
strong evidence that SN 2007od formed new dust before day 232. Late-time
observations reveal a flattening of the visible lightcurve. This flattening is
a strong indication of the presence of a light echo, which likely accounts for
much of the broad, underlying Halpha component seen at late-times. We believe
the multi-peaked Halpha emission is consistent with the interaction of the
ejecta with a circumstellar ring or torus (for the inner components at \pm1500
km s-1), and a single blob or cloud of circumstellar material out of the plane
of the CSM ring (for the outer component at -5000 km s-1). The most probable
location for the formation of new dust is in the cool dense shell created by
the interaction between the expanding ejecta and its CSM. Monte Carlo radiative
transfer modeling of the dust emission from SN 2007od implies that up to 4x
10-4Msun of new dust has formed. This is similar to the amounts of dust formed
in other CCSNe such as SNe 1999em, 2004et, and 2006jc.Comment: 35 pages, 6 figures. Accepted for publication in Ap
Evidence for Pre-Existing Dust in the Bright Type IIn SN 2010jl
SN 2010jl was an extremely bright, Type IIn SNe which showed a significant IR
excess no later than 90 days after explosion. We have obtained Spitzer 3.6 and
4.5 \mum and JHK observations of SN 2010jl \sim90 days post explosion. Little
to no reddening in the host galaxy indicated that the circumstellar material
lost from the progenitor must lie in a torus inclined out of the plane of the
sky. The likely cause of the high mid-IR flux is the reprocessing of the
initial flash of the SN by pre-existing circumstellar dust. Using a 3D Monte
Carlo Radiative Transfer code, we have estimated that between 0.03-0.35 Msun of
dust exists in a circumstellar torus around the SN located 6 \times 10 ^17 cm
away from the SN and inclined between 60-80\cdot to the plane of the sky. On
day 90, we are only seeing the illumination of approximately 5% of this torus,
and expect to see an elevated IR flux from this material up until day \sim 450.
It is likely this dust was created in an LBV-like mass loss event of more than
3 Msun, which is large but consistent with other LBV progenitors such as {\eta}
Carinae.Comment: Accepted in A
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