1,870 research outputs found
Evidence of microbial activity from a shallow water whale fall (Voghera, northern Italy)
The fossil bones, associated carbonate cements and enclosing concretion of a Miocene mysticete from inner shelf deposits (Monte Vallassa Formation, northern Italy) were analyzed for evidence of microbial activity. Optical and scanning electron microscopy, Raman spectroscopy, and stable C and O isotope geochemistry were used for high spatial resolution microfacies and biosedimentological analyses. Whale cancellous bones were filled by different carbonate cements including microcrystalline dolomite, rhombohedral dolomite and sparry calcite. Biofabric and biominerals such as microbial peloids, clotted textures and pyrite framboids were associated with the dolomite cements. Dolomite inside cancellous bones and in the enclosing concretion showed similar isotopic values (avg δ 13C: -7.12‰; avg δ 18O: +3.81‰), depleted with respect to the (late) sparry calcite cement (avg δ 13C: -0.55‰; avg δ 18O: -0.98‰). Microcrystalline barite (BaSO 4) was observed on the external surface of the bones. In addition, two different types of microborings were recognized, distinguished by their size and morphology and were ascribed respectively to prokaryote and fungal trace makers. Our results testify for the development of a diverse microbial ecosystem during the decay of a shallow water whale carcass, which could be detected in the fossil record. However, none of the observed biosignatures (e.g., microbial peloids, clotted textures) can be used alone as a positive fossil evidence of the general development of a sulfophilic stage of whale fall ecological succession. The occurrence of the hard parts of chemosynthetic invertebrates associated with fossil whale bones is still the more convincing proof of the development of a sulfide-base chemoautotrophic ecosystem. © 2011 Elsevier B.V
The Lightest Pseudo-Goldstone Boson at Future e+e- Colliders
In a class of models of dynamical symmetry breaking not ruled out by the
available data, the lightest neutral pseudo-Nambu-Goldstone boson P0 contains
only down-type techniquarks and charged technileptons. Its mass scale is
naturally determined by the b-quark and therefore it is likely to be light. As
the presence of pseudo-Nambu-Goldstone bosons in models of dynamical symmetry
breaking is a quite general feature, the search of the P0 at colliders is an
interesting opportunity of putting limits on or discovering a dynamical
electroweak symmetry breaking scenario. In this note we discuss the prospects
for discovering and studying the P0 at future e+e- and gamma-gamma colliders.Comment: 15 pages, 8 figures, LaTeX (epsfig), Proceedings of the Second
ECFA/DESY Study on Physics Studies for a Future Linear Collide
Vortex and half-vortex dynamics in a spinor quantum fluid of interacting polaritons
Spinorial or multi-component Bose-Einstein condensates may sustain fractional
quanta of circulation, vorticant topological excitations with half integer
windings of phase and polarization. Matter-light quantum fluids, such as
microcavity polaritons, represent a unique test bed for realising strongly
interacting and out-of-equilibrium condensates. The direct access to the phase
of their wavefunction enables us to pursue the quest of whether half vortices
---rather than full integer vortices--- are the fundamental topological
excitations of a spinor polariton fluid. Here, we are able to directly generate
by resonant pulsed excitations, a polariton fluid carrying either the half or
full vortex states as initial condition, and to follow their coherent evolution
using ultrafast holography. Surprisingly we observe a rich phenomenology that
shows a stable evolution of a phase singularity in a single component as well
as in the full vortex state, spiraling, splitting and branching of the initial
cores under different regimes and the proliferation of many vortex anti-vortex
pairs in self generated circular ripples. This allows us to devise the
interplay of nonlinearity and sample disorder in shaping the fluid and driving
the phase singularities dynamicsComment: New version complete with revised modelization, discussion and added
material. 8 pages, 7 figures. Supplementary videos:
https://drive.google.com/folderview?id=0B0QCllnLqdyBfmc2ai0yVF9fa2g2VnZodGUwemVkLThBb3BoOVRKRDJMS2dUdjlZdkRTQk
PARP inhibitors affect growth, survival and radiation susceptibility of human alveolar and embryonal rhabdomyosarcoma cell lines
PARP inhibitors (PARPi) are used in a wide range of human solid tumours but a limited evidence is reported in rhabdomyosarcoma (RMS), the most frequent childhood soft-tissue sarcoma. The cellular and molecular effects of Olaparib, a specific PARP1/2 inhibitor, and AZD2461, a newly synthesized PARP1/2/3 inhibitor, were assessed in alveolar and embryonal RMS cells both as single-agent and in combination with ionizing radiation (IR)
Dimensionless Coupling of Bulk Scalars at the LHC
We identify the lowest-dimension interaction which is possible between
Standard Model brane fields and bulk scalars in 6 dimensions. The
lowest-dimension interaction is unique and involves a trilinear coupling
between the Standard Model Higgs and the bulk scalar. Because this interaction
has a dimensionless coupling, it depends only logarithmically on ultraviolet
mass scales and heavy physics need not decouple from it. We compute its
influence on Higgs physics at ATLAS and identify how large a coupling can be
detected at the LHC. Besides providing a potentially interesting signal in
Higgs searches, such couplings provide a major observational constraint on 6D
large-extra-dimensional models with scalars in the bulk.Comment: 20 page
Unraveling the Complexity of Tourist Experience with NFC Technology and Mobile Wallets
By considering the tourist experience as a complex dynamic system, in this paper we depict the traveler as a kybernetes (\u3ba\u3c5\u3b2\u3b5\u3c1\u3bd\u3ae\u3c4\u3b7\u3c2 is the ancient Greek word for \u2018sea captain\u2019, \u2018steersman\u2019, or \u2018governor\u2019) in search of powerful tools to help him or her to obtain directions in the mare magnum of complexity, overcoming the fear of action and taking decisions. We focus our attention on the key role of Near Field Communication technology and mobile wallet as \u2018attenuators of complexity\u2019 in the travel and tourism industr
Testing the performance of a blind burst statistic
In this work we estimate the performance of a method for the detection of
burst events in the data produced by interferometric gravitational wave
detectors. We compute the receiver operating characteristics in the specific
case of a simulated noise having the spectral density expected for Virgo, using
test signals taken from a library of possible waveforms emitted during the
collapse of the core of Type II Supernovae.Comment: 8 pages, 6 figures, Talk given at the GWDAW2002 worksho
Les Houches "Physics at TeV Colliders 2003" Beyond the Standard Model Working Group: Summary Report
The work contained herein constitutes a report of the ``Beyond the Standard
Model'' working group for the Workshop "Physics at TeV Colliders", Les Houches,
France, 26 May--6 June, 2003. The research presented is original, and was
performed specifically for the workshop. Tools for calculations in the minimal
supersymmetric standard model are presented, including a comparison of the dark
matter relic density predicted by public codes. Reconstruction of
supersymmetric particle masses at the LHC and a future linear collider facility
is examined. Less orthodox supersymmetric signals such as non-pointing photons
and R-parity violating signals are studied. Features of extra dimensional
models are examined next, including measurement strategies for radions and
Higgs', as well as the virtual effects of Kaluza Klein modes of gluons. An LHC
search strategy for a heavy top found in many little Higgs model is presented
and finally, there is an update on LHC studies.Comment: 113 pages, ed B.C. Allanach, v5 has changes to part XV
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