4,874 research outputs found
Spectral geometry as a probe of quantum spacetime
Employing standard results from spectral geometry, we provide strong evidence
that in the classical limit the ground state of three-dimensional causal
dynamical triangulations is de Sitter spacetime. This result is obtained by
measuring the expectation value of the spectral dimension on the ensemble of
geometries defined by these models, and comparing its large scale behaviour to
that of a sphere (Euclidean de Sitter). From the same measurement we are also
able to confirm the phenomenon of dynamical dimensional reduction observed in
this and other approaches to quantum gravity -- the first time this has been
done for three-dimensional causal dynamical triangulations. In this case, the
value for the short-scale limit of the spectral dimension that we find is
approximately 2. We comment on the relevance of these results for the
comparison to asymptotic safety and Horava-Lifshitz gravity, among other
approaches to quantum gravity.Comment: 25 pages, 6 figures. Version 2: references to figures added,
acknowledgment added
Micronutrients in a neurodegenerative disorder such as Amyotrophic Lateral Sclerosis
This PhD thesis research project is aimed at investigating the role of micronutrients in Amyotrophic Lateral Scelrosis. Their levels will be correlated with the disease status to evaluate how micronutrients and their regulatory pathways could influence the manifestation and the difference of clinical signs of disease in pre-symptomatic subjects thus explaining the wide phenotypic spectrum of disease. This will be performed through different approaches: clinical, biochemical and genetic in order to obtain a nutritional outcome. This could help to elucidate the role of micronutrients and its metabolism in the pathogenesis and/or in the progression of ALS
Metals and proteomics of the biological fluids in ALS patients: preliminary data
Biochemical analyses described in the PhD dissertation project were performed on a small cohort of subjects affected by sporadic ALS, all originating from a restricted geographical area. In detail, serum and urine levels of a customized panel of metals were measured; proteomic analyses were performed on urine by SDS-PAGE and on serum by 2D-Electrophoresis. Data collected through a survey on lifestyle and nutrition were analyzed by Artificial Neural Networks
Lattice Glass Models
Motivated by the concept of geometrical frustration, we introduce a class of
statistical mechanics lattice models for the glass transition. Monte Carlo
simulations in three dimensions show that they display a dynamical glass
transition which is very similar to that observed in other off-lattice systems
and which does not depend on a specific dynamical rule. Whereas their analytic
solution within the Bethe approximation shows that they do have a discontinuous
glass transition compatible with the numerical observations.Comment: 4 pages, 2 figures; minor change
Influência da posição e formato de corte na preferência sensorial de abacaxi 'pérola' minimamente processado.
Generation of Phenothiazine with Potent Anti-TLK1 Activity for Prostate Cancer Therapy
Through in vitro kinase assays and docking studies, we report the synthesis and biological evaluation of a phenothiazine analog J54 with potent TLK1 inhibitory activity for prostate cancer (PCa) therapy. Most PCa deaths result from progressive failure in standard androgen deprivation therapy (ADT), leading to metastatic castration-resistant PCa. Treatments that can suppress the conversion to mCRPC have high potential to be rapidly implemented in the clinics. ADT results in increased expression of TLK1B, a key kinase upstream of NEK1 and ATR and mediating the DNA damage response that typically results in temporary cell-cycle arrest of androgen-responsive PCa cells, whereas its abrogation leads to apoptosis. We studied J54 as a potent inhibitor of this axis and as a mediator of apoptosis in vitro and in LNCaP xenografts, which has potential for clinical investigation in combination with ADT. J54 has low affinity for the dopamine receptor in modeling and competition studies and weak detrimental behavioral effects in mice and C. elegans
Updated Brazilian's georeferenced soil database: an improvement for international scientific information exchanging.
A new continuum limit of matrix models
We define a new scaling limit of matrix models which can be related to the
method of causal dynamical triangulations (CDT) used when investigating
two-dimensional quantum gravity. Surprisingly, the new scaling limit of the
matrix models is also a matrix model, thus explaining why the recently
developed CDT continuum string field theory (arXiv:0802.0719) has a
matrix-model representation (arXiv:0804.0252).Comment: 17 pages, 2 figure
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