10,117 research outputs found
Many-nodes/many-links spinfoam: the homogeneous and isotropic case
I compute the Lorentzian EPRL/FK/KKL spinfoam vertex amplitude for regular
graphs, with an arbitrary number of links and nodes, and coherent states peaked
on a homogeneous and isotropic geometry. This form of the amplitude can be
applied for example to a dipole with an arbitrary number of links or to the
4-simplex given by the compete graph on 5 nodes. All the resulting amplitudes
have the same support, independently of the graph used, in the large j (large
volume) limit. This implies that they all yield the Friedmann equation: I show
this in the presence of the cosmological constant. This result indicates that
in the semiclassical limit quantum corrections in spinfoam cosmology do not
come from just refining the graph, but rather from relaxing the large j limit.Comment: 8 pages, 4 figure
Summary of the CMS Discovery Potential for the MSSM SUSY Higgses
This work summarises the present understanding of the expected MSSM SUSY
Higgs reach for CMS. Many of the studies presented here result from detailed
detector simulations incorporating final CMS detector design and response. With
30 fb-1 the h -> gamma,gamma and h -> bb channels allow to cover most of the
MSSM parameter space. For the massive A,H,H+ MSSM Higgs states the channels A,H
-> tau,tau and H+ -> tau,nu turn out to be the most profitable ones in terms of
mass reach and parameter space coverage. Consequently CMS has made a big effort
to trigger efficiently on taus. Provided neutralinos and sleptons are not too
heavy, there is an interesting complementarity in the reaches for A,H ->
tau,tau and A,H -> chi,chi.Comment: 19 pages, 27 figure
Euclidean three-point function in loop and perturbative gravity
We compute the leading order of the three-point function in loop quantum
gravity, using the vertex expansion of the Euclidean version of the new spin
foam dynamics, in the region of gamma<1. We find results consistent with Regge
calculus in the limit gamma->0 and j->infinity. We also compute the tree-level
three-point function of perturbative quantum general relativity in position
space, and discuss the possibility of directly comparing the two results.Comment: 16 page
On the Ultraviolet Behaviour of Newton's constant
We clarify a point concerning the ultraviolet behaviour of the Quantum Field
Theory of gravity, under the assumption of the existence of an ultraviolet
Fixed Point. We explain why Newton's constant should to scale like the inverse
of the square of the cutoff, even though it is technically inessential. As a
consequence of this behaviour, the existence of an UV Fixed Point would seem to
imply that gravity has a built-in UV cutoff when described in Planck units, but
not necessarily in other units.Comment: 8 pages; CQG class; minor changes and rearrangement
Reference genes for transcriptional analysis of flowering and fruit ripening stages in apple (Malus 3 domestica Borkh.).
Apple (Malus 9 domestica Borkh.) is the most important deciduous tree fruit crop grown around the world. Comparisons of gene expression profiles from different tissues, conditions or cultivars are valuable scientific tools to better understand the gene expression changes behind important silvicultural and nutritional traits. However, the accuracy of techniques employed to access gene expression is dependent on the evaluation of stable reference genes for data normalization to avoid statistical significance undue or incorrect conclusions. The objective of this work was to select the best genes to be used as references for gene expression studies in apple trees by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Vegetative and reproductive tissues of the apple ??Gala?? cultivar were evaluated during their seasonal cycle of growth and dormancy. The expression of 23 traditional housekeeping genes or genes suggested as constitutive by microarray data was investigated. Tested combinations of primers allowed the specific amplification and the generation of suitable efficiency curves for gene expression studies by RT-qPCR. Gene stability was determined by two different statistical descriptors, geNorm and Norm-Finder. The known variable PAL gene expression was used to validate selected normalizers. Results obtained allowed us to conclude that MDH, SAND, THFS, TMp1 and WD40 are the best reference genes to accurately normalize the relative transcript abundances using RT-qPCR in various tissues of apple.DOI 10.1007/s11032-014-0078-
Use of active caspase 3 and tunel assays to estimate embryonic quality in in vivo Santa Ines ewe embryos.
Edição dos proceedings da Annual Conference or the International Embryo Transfer Society, Orlando, Florida, 2011
Reference gene selection for gene expression studies in apple.
Apple (Malus x domestica Borkh.) is the most important deciduous tree fruit crop grown around the world, and also in the Southern of Brazil. Researches on apple genetic breeding include disease resistance mechanisms, grafting, chilling requirement, fruit ripening and production of nutraceutical compounds.Resumo
A spin foam model for general Lorentzian 4-geometries
We derive simplicity constraints for the quantization of general Lorentzian
4-geometries. Our method is based on the correspondence between coherent states
and classical bivectors and the minimization of associated uncertainties. For
spacelike geometries, this scheme agrees with the master constraint method of
the model by Engle, Pereira, Rovelli and Livine (EPRL). When it is applied to
general Lorentzian geometries, we obtain new constraints that include the EPRL
constraints as a special case. They imply a discrete area spectrum for both
spacelike and timelike surfaces. We use these constraints to define a spin foam
model for general Lorentzian 4-geometries.Comment: 27 pages, 1 figure; v4: published versio
Optimal Dithering Configuration Mitigating Rayleigh-Backscattering-Induced Distortion in Radioastronomic Optical Fiber Systems
In the context of Radioastronomic applications where the Analog Radio-over-Fiber technology is used for the antenna downlink, detrimental nonlinearity effects arise because of the interference between the forward signal generated by the laser and the Rayleigh backscattered one which is re-forwarded by the laser itself toward the photodetector. The adoption of the so called dithering technique, which involves the direct modulation of the laser with a sinusoidal tone and takes advantage of the laser chirping phenomenon, has been proved to reduce such Rayleigh Back Scattering - induced nonlinearities. The frequency and the amplitude of the dithering tone should both be as low as possible, in order to avoid undesired collateral effects on the received spectrum as well as keep at low levels the global energy consumption. Through a comprehensive analysis of dithered Radio over Fiber systems, it is demonstrated that a progressive reduction of the dithering tone frequency affects in a peculiar fashion both the chirping characteristics of the field emitted by the laser and the spectrum pattern of the received signal at the fiber end. Accounting for the concurrent effects caused by such phenomena, optimal operating conditions are identified for the implementation of the dithering tone technique in radioastronomic systems
Developing a microbial consortium for removing nutrients in dishwasher wastewater: towards a biofilter for its up-cycling
Microbial consortia are effective biofilters to treat wastewaters, allowing for resource recovery and water remediation.
To re-use and save water in the domestic cycle, we assembled a suspended biofilm, a ‘biofilter’ to treat dishwasher wastewater. Bacterial monocultures of both photo- and hetero-trophs were assembled in an increasingly complex fashion to test their nutrient stripping capacity. This ‘biofilter’ is the core of an integrated system devoted to re-using and upcycling of reconditioned wastewater, partly in subsequent dishwasher cycles and partly into a vertical garden for plant food cultivation.
The biofilter has been assembled based on a strain of the photosynthetic, filamentous cyanobacterium Trichormus variabilis, selected to produce an oxygen evolving scaffold, and three heterotrophic aerobic bacterial isolates coming from the dishwasher wastewater itself: Acinetobacter, Exiguobacterium and Pseudomonas spp. The consortium has been constructed starting with 16 isolates tested one-to-one with T. variabilis and then selecting the heterotrophic microbes up to a final one-to-three consortium, which included two dominant and a rare component of the wastewater community. This consortium thrives in the wastewater much better than T. variabilis alone, efficiently stripping N and P in short time, a pivotal step to the reuse and saving of water in household appliances
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