GRB Flares: UV/Optical Flaring (Paper I)

We present a new algorithm for the detection of flares in gamma-ray burst (GRB) light curves and use this algorithm to detect flares in the UV/optical. The algorithm makes use of the Bayesian Information Criterion (BIC) to analyze the residuals of the fitted light curve, removing all major features, and to determine the statistically best fit to the data by iteratively adding additional `breaks' to the light curve. These additional breaks represent the individual components of the detected flares: T_start, T_stop, and T_peak. We present the detection of 119 unique flaring periods detected by applying this algorithm to light curves taken from the Second Swift Ultraviolet/Optical Telescope (UVOT) GRB Afterglow Catalog. We analyzed 201 UVOT GRB light curves and found episodes of flaring in 68 of the light curves. For those light curves with flares, we find an average number of ~2 flares per GRB. Flaring is generally restricted to the first 1000 seconds of the afterglow, but can be observed and detected beyond 10^5 seconds. More than 80% of the flares detected are short in duration with Delta t/t of < 0.5. Flares were observed with flux ratios relative to the underlying light curve of between 0.04 to 55.42. Many of the strongest flares were also seen at greater than 1000 seconds after the burst.Comment: Submitted to ApJ. 20 pages (including 8 figures and 1 table

Invariant measures on multimode quantum Gaussian states

We derive the invariant measure on the manifold of multimode quantum Gaussian states, induced by the Haar measure on the group of Gaussian unitary transformations. To this end, by introducing a bipartition of the system in two disjoint subsystems, we use a parameterization highlighting the role of nonlocal degrees of freedom -- the symplectic eigenvalues -- which characterize quantum entanglement across the given bipartition. A finite measure is then obtained by imposing a physically motivated energy constraint. By averaging over the local degrees of freedom we finally derive the invariant distribution of the symplectic eigenvalues in some cases of particular interest for applications in quantum optics and quantum information.Comment: 17 pages, comments are welcome. v2: presentation improved and typos corrected. Close to the published versio

Velocity fluctuations of noisy reaction fronts propagating into a metastable state: testing theory in stochastic simulations

The position of a reaction front, propagating into a metastable state, fluctuates because of the shot noise of reactions and diffusion. A recent theory [B. Meerson, P.V. Sasorov, and Y. Kaplan, Phys. Rev. E 84, 011147 (2011)] gave a closed analytic expression for the front diffusion coefficient in the weak noise limit. Here we test this theory in stochastic simulations involving reacting and diffusing particles on a one-dimensional lattice. We also investigate a small noise-induced systematic shift of the front velocity compared to the prediction from the spatially continuous deterministic reaction-diffusion equation.Comment: 5 pages, 5 figure

Influence of the pressing system on pomegranate juice physical-chemical properties

Pomegranate juice has many health properties as the fruits contain anticarcinogenic, antimicrobial and antiviral compounds. Its consumption has greatly increased throughout the world in recent years due to the potential of its different components, polyphenols and anthocyanins among all. Many studies have been performed on the pomegranate juice yield demonstrating its influence on the organoleptic and physicochemical properties of the juice. Commercial pomegranate juice production involves pressing fruits procedures. As a consequence, there is a need to investigate the pressing machine types and optimization in order to achieve juice yield and enhance its health properties. The aim of this study was to assess the influence of the pressing systems on pomegranate juice yield and health properties after the extraction. Pomegranate fruits of the Wonderful One variety were manually harvested in November 2014 and mechanically processed to extract juice. Two different pressing systems were used. The first one was an hydraulic pressing machine where the fruits were put after being sliced in half; the second extraction method consisted in using a destemming machine for the entire fruit followed by a pneumatic press, typically applied in grape processing. The juices obtained with the two systems were analyzed and compared in order to identify the extraction performances and quantitatively identify the health care of the juice properties

Reconstruction of time-dependent coefficients: a check of approximation schemes for non-Markovian convolutionless dissipative generators

We propose a procedure to fully reconstruct the time-dependent coefficients of convolutionless non-Markovian dissipative generators via a finite number of experimental measurements. By combining a tomography based approach with a proper data sampling, our proposal allows to relate the time-dependent coefficients governing the dissipative evolution of a quantum system to experimentally accessible quantities. The proposed scheme not only provides a way to retrieve full information about potentially unknown dissipative coefficients but also, most valuably, can be employed as a reliable consistency test for the approximations involved in the theoretical derivation of a given non-Markovian convolutionless master equation.Comment: 11 pages, 4 figures, revised version published on PR

Influence of biochar on the physical, chemical and retention properties of an amended sandy soil

Soil porosity plays an important role in soil-water retention and water availability to crops, potentially affecting both agricultural practices and environmental sustainability. The pore structure controls fluid flow and transport through the soil, as well as the relationship between the properties of individual minerals and plants. Moreover, the anthropogenic pressure on soil properties has produced numerous sites with extensive desertification process close to residential areas. Biochar (biologically derived charcoal) is produced by pyrolysis of biomasses under low oxygen conditions, and it can be applied for recycling organic waste in soils and increase soil fertility, improving soil structure and enhancing soil water storage and soil water movement. Soil application of biochar might have agricultural, environmental and sustainability advantages over the use of organic manures or compost, as it is a porous material with a high inner surface area. The main objectives of the present study were to investigate the possible application of biochar from forest residues, derived from mechanically chipped trunks and large branches of Abies alba M., Larix decidua Mill., Picea excelsa L., Pinus nigra A. and Pinus sylvestris L. pyrolysed at 450 C for 48h, to improve soil structural and hydraulic properties (achieving a stabilization of soil). Different amount of biochar were added to a desertic sandy soil, and the effect on soil porosity water retention and water available to crops were investigated. The High Energy Moisture Characteristic (HEMC) technique was applied to investigate soil-water retention at high-pressure head levels. The adsorption and desorption isotherms of N2 on external surfaces were also determined in order to investigate micro and macro porosity ratio. Both the described model of studies on adsorption-desorption experiments with the applied isotherms model explain the increasing substrate porosity with a particular attention to the macro and micro porosity, respectively

Influence of O2 on extra virgin olive oil fatty acids composition during malaxation

Many variables are related to extra virgin olive oil (EVOO) quality and, therefore, to its polyphenols content and fatty acids composition including the steps that lead to EVOO extraction, considering that it is mainly contained in the vacuoles of the fruit mesocarp. The main steps of EVOO production are: harvest, crushing, malaxation, centrifugation, storage and filtration. Considering the olive oil extraction procedures, many studies have been conducted in recent years on oil mill plant and processes for improving EVOO quality. Malaxer is the most studied machine among all; it is responsible for malaxation, which represents a very important and critical step in the EVOO extraction process. Many studies focus on the control of oxygen in the malaxer headspace, with the aim of determining its influence on EVOO quality evaluating volatile and phenolic components. Considering these factors, the main objective of the present study was to evaluate the influence of the malaxer headspace oxygen concentration on EVOO fatty acids composition from cv. Nocellara del Belice olives. The results show that oxygen content in the malaxer headspace, in different time-points and concentrations during the process, influences EVOO fatty acids composition

Conformational behaviour of humic substances at different depths along a profile of a Lithosol under loblolly (Pinus taeda) plantation.

Published in 6th EGU General Assembly 2009

Modeling of lattice structures energy absorption under impact loads

Lattice structures are promising design solutions for lightweight components in many industrial fields as aeronautics and space. The multifunctional design approach aims to combine in the same component several capabilities, including the ability to absorb impact energy with high efficiency. The additive manufacturing of metals is presently opening to innovative constructive approaches where static strength, lightweight and impact behavior must be considered together in design and simulation. This paper introduces the modeling results of the energy absorbed by different lattice cells topologies under impacts