Towards a cross-correlation approach to strong-field dynamics in Black Hole spacetimes

The qualitative and quantitative understanding of near-horizon gravitational dynamics in the strong-field regime represents a challenge both at a fundamental level and in astrophysical applications. Recent advances in numerical relativity and in the geometric characterization of black hole horizons open new conceptual and technical avenues into the problem. We discuss here a research methodology in which spacetime dynamics is probed through the cross-correlation of geometric quantities constructed on the black hole horizon and on null infinity. These two hypersurfaces respond to evolving gravitational fields in the bulk, providing canonical "test screens" in a "scattering"-like perspective onto spacetime dynamics. More specifically, we adopt a 3+1 Initial Value Problem approach to the construction of generic spacetimes and discuss the role and properties of dynamical trapping horizons as canonical inner "screens" in this context. We apply these ideas and techniques to the study of the recoil dynamics in post-merger binary black holes, an important issue in supermassive galactic black hole mergers.Comment: 16 pages, 5 figures, contribution to the proceedings volume of the Spanish Relativity Meeting ERE2011: "Towards new paradigms", Madrid, Spain, 29 Aug-2 Sep 201

Dielectric properties of Li2O-3B2O3 glasses

The frequency and temperature dependence of the dielectric constant and the electrical conductivity of the transparent glasses in the composition Li2O-3B2O3 (LBO) were investigated in the 100 Hz- 10 MHz frequency range. The dielectric constant and the loss in the low frequency regime were electrode material dependent. Dielectric and electrical relaxations were respectively analyzed using the Cole-Cole and electric modulus formalisms. The dielectric relaxation mechanism was discussed in the framework of electrode and charge carrier (hopping of the ions) related polarization using generalized Cole-Cole expression. The frequency dependent electrical conductivity was rationalized using Jonscher's power law. The activation energy associated with the dc conductivity was 0.80 \pm 0.02 eV, which was ascribed to the motion of Li+ ions in the glass matrix. The activation energy associated with dielectric relaxation was almost equal to that of the dc conductivity, indicating that the same species took part in both the processes. Temperature dependent behavior of the frequency exponent (n) suggested that the correlated barrier hopping model was the most apposite to rationalize the electrical transport phenomenon in Li2O-3B2O3 glasses. These glasses on heating at 933 K/10h resulted in the known non-linear optical phase LiB3O5.Comment: 32 pages, 13 figure

Charge and momentum transfer in supercooled melts: Why should their relaxation times differ?

The steady state values of the viscosity and the intrinsic ionic-conductivity of quenched melts are computed, in terms of independently measurable quantities. The frequency dependence of the ac dielectric response is estimated. The discrepancy between the corresponding characteristic relaxation times is only apparent; it does not imply distinct mechanisms, but stems from the intrinsic barrier distribution for $\alpha$-relaxation in supercooled fluids and glasses. This type of intrinsic ``decoupling'' is argued not to exceed four orders in magnitude, for known glassformers. We explain the origin of the discrepancy between the stretching exponent $\beta$, as extracted from $\epsilon(\omega)$ and the dielectric modulus data. The actual width of the barrier distribution always grows with lowering the temperature. The contrary is an artifact of the large contribution of the dc-conductivity component to the modulus data. The methodology allows one to single out other contributions to the conductivity, as in ``superionic'' liquids or when charge carriers are delocalized, implying that in those systems, charge transfer does not require structural reconfiguration.Comment: submitted to J Chem Phy

Diabetes risk assessment: clinical screening tools

The epidemic of type 2 diabetes (T2D) continues to soar worldwide. Driven by changes in human habits, from availability of energy dense processed foods to the decrease of physical activity, T2D constitutes already a heavy burden of disease and a worrisome barrier for the sustainability of National Health Systems. Indeed, it affects 415 million people (8.8% prevalence), was responsible for 5.0 million deaths in 2015, and is estimated to cost 1/9 of all Health expenses. Within Europe, Portugal is reported as having the highest prevalence of diabetes: an estimated 9.6% by World Standard Population. But if we take into consideration the age distribution of the Portuguese population, then estimates increase to 12.9%. This means that 1 million Portuguese have diabetes, with almost half of these still undiagnosed. Additionally, 2 million (a third of the adult population) are estimated to have intermediate hyperglycemia (or prediabetes), being largely unaware of this condition.info:eu-repo/semantics/publishedVersio

Procalcitonin: a marker for predicting the risk lower extremity amputation in infected wounds

Diabetes Mellitus is a metabolic disorder that is growing at epidemic proportions worldwide and is consensually classified in type 1 Diabetes, type 2 Diabetes and Gestational Diabetes. One of the most common complication of diabetes is the lower extremity is the diabetic foot ulcer (DFU). Diabetes is also the most common cause of lower extremity amputation (LEA). Several foot disorders, such as foot ulcerations and infections are a major source of morbidity and a leading cause of hospitalization for persons with diabetes. Thus, ulceration, infection, gangrene, and limb amputation are major complications of the disease, estimated to cost billions of dollars each year and have attracted the attention of health policy providers.info:eu-repo/semantics/publishedVersio

BORAZANs: Tunable Fluorophores Based on 2-(Pyrazolyl)aniline Chelates of Diphenylboron

The reaction between 2-pyrazolyl-4-X-anilines, H(pzAnX), (X = para-OMe (L1), Me (L2), H (L3), Cl (L4), CO2Et (L5), CF3 (L6), CN (L7)) and triphenylboron in boiling toluene affords the respective, highly emissive N,N‘-boron chelate complexes, BPh2(pzAnX) (X = para-OMe (1), Me (2), H (3), Cl (4), CO2Et (5), CF3 (6), CN (7)) in high yield. The structural, electrochemical, and photophysical properties of the new boron complexes can be fine-tuned by varying the electron-withdrawing or -donating power of the para-aniline substituent (delineated by the substituent\u27s Hammett parameter). Those complexes with electron-withdrawing para-aniline substituents such as CO2Et (5), CF3 (6), and CN (7) have more planar chelate rings, more ‘quinoidal\u27 disortion in the aniline rings, greater chemical stability, higher oxidation potentials, and more intense (φF = 0.81 for 7 in toluene), higher-energy (blue) fluorescent emission compared to those with electron-donating substituents. Thus, for 1 the oxidation potential is 0.53 V versus Ag/AgCl (compared to 1.12 V for 7), and the emission is tuned to the yellow-green but at an expense in terms of lower quantum yields (φF = 0.07 for 1 in toluene) and increased chemical reactivity. Density functional calculations (B3LYP/6-31G*) on PM3 energy-minimized structures of the ligands and boron complexes reproduced experimentally observed data and trends and provided further insight into the nature of the electronic transitions

Carotenoid retention in orange flesh sweet potato flour during storage.

Resumo TH28

Micropedologia de um Argissolo amarelo com horizontes antrópicos (Terra Preta de Índio) na Amazônia Central.

Estudos micropedológicos foram carreados em Terra Preta de Índio (TPI) com o objetivo de elucidar os processos envolvidos em sua gênese, bem como suas formas de utilização pré-colombiana. Blocos indeformados de solo foram coletados por horizonte e em suas respectivas transições em um perfil de Argissolo Amarelo A Antrópico (TPI) localizado no município de Iranduba, AM. As lâminas delgadas confeccionadas a partir dos blocos foram descritas por meio de microscopia óptica. Os resultados mostraram que os processos envolvidos na gênese desse solo envolveram: i) condições pedoambientais diferentes das atuais (pedorrelíquias - nódulos ferruginosos); ii) argiluviação, indicada por revestimentos de ferri-argilãs orientados na parede de poros entre agregados e canais; iii) migração de ferro impregnando o fundo matricial (cutãs de difusão); iv) bioturbação, atestada por preenchimento de poros por pelotas fecais e microagregação zoogenética e v) antropismo, que contribuiu com a queima de resíduos (partículas de carvões) e descarte de artefatos cerâmicos. A análise dos fragmentos cerâmicos corroborou a utilização de cauixi (Tubella reticulata e Parnula betesil) e cariapé (Bignoniacea) como antiplástico para o seu fabrico