Fisher matrix forecasts for astrophysical tests of the stability of the fine-structure constant

We use Fisher Matrix analysis techniques to forecast the cosmological impact of astrophysical tests of the stability of the fine-structure constant to be carried out by the forthcoming ESPRESSO spectrograph at the VLT (due for commissioning in late 2017), as well by the planned high-resolution spectrograph (currently in Phase A) for the European Extremely Large Telescope. Assuming a fiducial model without $\alpha$ variations, we show that ESPRESSO can improve current bounds on the E\"{o}tv\"{o}s parameter---which quantifies Weak Equivalence Principle violations---by up to two orders of magnitude, leading to stronger bounds than those expected from the ongoing tests with the MICROSCOPE satellite, while constraints from the E-ELT should be competitive with those of the proposed STEP satellite. Should an $\alpha$ variation be detected, these measurements will further constrain cosmological parameters, being particularly sensitive to the dynamics of dark energy.Comment: Phys. Lett. B (in press

Tipos nomenclaturais do Herbário IAN: organização, caracterização e divulgação.

Organizadores: Arion Tulio Aranda e Silvana Carvalho Thiengo

Multiscale model for the effects of adaptive immunity suppression on the viral therapy of cancer

Oncolytic virotherapy - the use of viruses that specifically kill tumor cells - is an innovative and highly promising route for treating cancer. However, its therapeutic outcomes are mainly impaired by the host immune response to the viral infection. In the present work, we propose a multiscale mathematical model to study how the immune response interferes with the viral oncolytic activity. The model assumes that cytotoxic T cells can induce apoptosis in infected cancer cells and that free viruses can be inactivated by neutralizing antibodies or cleared at a constant rate by the innate immune response. Our simulations suggest that reprogramming the immune microenvironment in tumors could substantially enhance the oncolytic virotherapy in immune-competent hosts. Viable routes to such reprogramming are either in situ virus-mediated impairing of CD$8^+$ T cells motility or blockade of B and T lymphocytes recruitment. Our theoretical results can shed light on the design of viral vectors or new protocols with neat potential impacts on the clinical practice.Comment: 14 pages, 4 figure

Low redshift constraints on energy-momentum-powered gravity models

There has been recent interest in the cosmological consequences of energy-momentum-powered gravity models, in which the matter side of Einstein's equations is modified by the addition of a term proportional to some power, $n$, of the energy-momentum tensor, in addition to the canonical linear term. In this work we treat these models as phenomenological extensions of the standard $\Lambda$CDM, containing both matter and a cosmological constant. We also quantitatively constrain the additional model parameters using low redshift background cosmology data that are specifically from Type Ia supernovas and Hubble parameter measurements. We start by studying specific cases of these models with fixed values of $n,$ which lead to an analytic expression for the Friedmann equation; we discuss both their current constraints and how the models may be further constrained by future observations of Type Ia supernovas for WFIRST complemented by measurements of the redshift drift by the ELT. We then consider and constrain a more extended parameter space, allowing $n$ to be a free parameter and considering scenarios with and without a cosmological constant. These models do not solve the cosmological constant problem per se. Nonetheless these models can phenomenologically lead to a recent accelerating universe without a cosmological constant at the cost of having a preferred matter density of around $\Omega_M\sim0.4$ instead of the usual $\Omega_M\sim0.3$. Finally we also briefly constrain scenarios without a cosmological constant, where the single component has a constant equation of state which needs not be that of matter; we provide an illustrative comparison of this model with a more standard dynamical dark energy model with a constant equation of state.Comment: 13+2 pages, 12+1 figures; A&A (in press

Effects of low-fat milk enriched with phytosterols on plasma cholesterol concentrations and hemorheological parameters of Wistar rats

© 2006 – IOS Press and the authors. All rights reservedClinical and experimental studies have shown that the use of phytosterol esters as a food ingredient reduces the plasma concentrations of cholesterol and LDL cholesterol, not affecting the HDL cholesterol levels. Based on the use of phytosterols as a food ingredient, we have conducted a 30-day feeding study with Wistar rats, drinking low-fat milk containing phytosterols, in order to evaluate the plasma cholesterol concentrations and the hemorheological parameters. Throughout the study, clinical observations, body weights and food and milk consumption were measured and at the end of the feeding period, blood samples were collected for biochemical and hemorheological determinations. There were no clinical changes, alterations in growth, food or milk consumption. In the plasma cholesterol and HDL concentrations there were no significant differences, but LDL levels decreased about 70%. In the hemorheological parameters, significant changes were observed in plasma viscosity and in membrane fluidity in all experimental groups. The blood viscosity and the erythrocyte deformability show significant improvements with the ingestion of the phytosterols enriched milk. With these results we conclude that phytosterols maintain their cholesterol lowering properties when incorporated in milk and can be considered a hypolipemic food component

Analog 16-hydrophone vertical line array for the acoustic - oceanographic buoy - AOB

SiPLAB Report 03/06, FCT, University of Algarve,2006.This report contains the user guide and the system reference for the analog 16-hydrophone AOB vertical line array. The array is a 67.5m long cable with 16 4m-spaced hydrophones and 17 digital thermistor sensors, distributed along its length. Each module has a dedicated preamplifier to increase signal strength at the hydrophone output and drive a balanced line to transmit the signal to the surface buoy's electronics. The thermistor sensors are digital devices that transmit the temperatures values through a 1-wire digital serial bus. This report presents the system user guide and the system reference guide. The user guide has instructions for system deployment, everyday usage and maintenance. The system reference guide is intended for specialized technicians for system repairing and/or upgrade.This work was partially supported by projects RADAR (POCTI/CTA/47719/2002) and UAB (POCI/MAR/59008/2004) from FCT, Portugal

On the number of invariant polynomials of matrix commutators

We study the possible numbers of nonconstant invariant polynomials of the matrix commutator XA - AX, when X varies.Praxis ProgramCAU

Colour and chlorophyll's degradation kinetics of frozen green beans (Phaseolus Vulgaris, L.)

Colour changes and chlorophyll's degradation of frozen green beans (Phaseolus vulgaris, L., variety bencanta) were studied during 250 days of storage at -7, -15 and -30°C. Chlorophyll's a and b losses were modelled by a first order reaction kinetics. Colour Hunter a and b coordinates and total colour difference were successfully described by a first order reversible model. The temperature effect was well mathematically described by the Arrhenius law, for both quality parameters