3,322 research outputs found
Harnack's Inequality for Parabolic De Giorgi Classes in Metric Spaces
In this paper we study problems related to parabolic partial differential
equations in metric measure spaces equipped with a doubling measure and
supporting a Poincare' inequality. We give a definition of parabolic De Giorgi
classes and compare this notion with that of parabolic quasiminimizers. The
main result, after proving the local boundedness, is a scale and location
invariant Harnack inequality for functions belonging to parabolic De Giorgi
classes. In particular, the results hold true for parabolic quasiminimizers
Earth-based lunar atmosphere investigation Final report
Instrumentation and results of earth-based spectrometric identification of lunar atmospheric constituents in visible regio
Ultrathin cellulose ester films: preparation, characterization and protein immobilization
In this study cellulose acetate butyrate (CAB) and carboxymehtylcellulose acetate butyrate (CMCAB) films adsorbed onto silicon wafers were characterized by means of ellipsometry, atomic force microscopy (AFM), sum frequency generation spectroscopy (SFG) and contact angle measurements. The adsorption behavior of lysozyme (LIS) or bovine serum albumin (BSA) onto CAB and CMCAB films was investigated. The amounts of adsorbed LIS or BSA onto CMCAB films were more pronounced than those onto CAB films due to the presence of carboxymethyl group in the CMCAB structure. Besides, the adsorption of BSA molecules on CMCAB films was more favored than that of LIS molecules. Antimicrobial effect of LIS bound to CAB or CMCAB layers was evaluated using Micrococcus luteus as substrate.FAPESPCNPqCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES
Static and dynamic cartographies of the biotopes of the grasshopper Rhammatocerus schistocercoides (Rehn, 1906) in the state of Mato Grosso, Brazil.
Student reactions to traumatic material in literature: Implications for trigger warnings
Introduction While trigger warnings have garnered significant debate, few studies have investigated how students typically respond to potentially triggering material. Method In this study, three hundred and fifty-five undergraduate students from four universities read a passage describing incidences of both physical and sexual assault. Longitudinal mea- sures of subjective distress, PTSD symptoms, and emotional reactivity were taken. Results Greater than 96% of participants read the triggering passage even when given a non-trig- gering alternative to read. Of those who read the triggering passage, those with triggering traumas did not report more distress although those with higher PTSD scores did. Two weeks later, those with trigger traumas and/or PTSD did not report an increase in trauma symptoms as a result of reading the triggering passage. Conclusions Students with relevant traumas do not avoid triggering material and the effects appear to be brief. Students with PTSD do not report an exacerbation of symptoms two weeks later as a function of reading the passage
Extended plane wave expansion formulation for viscoelastic phononic thin plates
The extended plane wave expansion (EPWE) formulation is derived to obtain the
complex band structure of flexural waves in viscoelastic thin phononic crystal
plates considering the Kirchhoff-Love plate theory. The presented formulation
yields the evanescent behavior of flexural waves in periodic thin plates
considering viscoelastic effects. The viscosity is modeled by the standard
linear solid model (SLSM), typically used to closely model the behavior of
polymers. It is observed that the viscoelasticity influences significantly both
the propagating and evanescent Bloch modes. The highest wave attenuation of the
viscoelastic phononic thin plate is found around a unit cell filling fraction
of 0.37 for higher frequencies considering the least attenuated wave mode. This
EPWE formulation broadens the suitable methods to handle evanescent flexural
waves in 2-D thin periodic plate systems considering the effects of
viscoelasticity on wave attenuation
Isolation of Root Endophytic Bacteria in Elephant Grass (\u3cem\u3ePennisetum purpureum\u3c/em\u3e Schum.) Cultivars
Elephant grass (Pennisetum purpureum Schum.) is one of the most productive warm-season grasses. Farmers utilize elephant grass in different forms, such as cut-and-carry operations, grazing, conserved forage (silage, hay), and as an energy source (Lira et al. 2010). Nitrogen (N) is an essential element for plant growth and development and it is usually a limiting factor for forage production in the tropics (Boddey et al. 2004). Biological N fixation (BNF) may occur in warm-season grasses by their association with diazotrophic bacteria. These bacteria colonize different niches in the host plant. Endophytic bacteria form colonies inside the plant tissue whereas epiphytic bacteria colonize plant external surfaces (Compant et al. 2010). Both types of bacteria may benefit host plants (Badri et al. 2009). This study evaluated endophytic diazotrophic bacteria density associated to the roots of different elephant grass cultivars (cvs. ‘Elefante B’, ‘Venezuela’, and ‘Pioneiro’) using two N-free growth media, at different evaluation periods
The use of tire rubber in the production of high-performance concrete
The advances in concrete technology lead to the search for alternative materials that provide improvements in concrete properties while at the same time collaborating with sustainable practices in construction. In this study, the influence of the incorporation of waste tire rubber on the mechanical properties of high-performance concrete was discussed. The waste rubber from the tire retreading process was used in partial substitution of the fine aggregate (sand) in the percentages of 7.5%, 15% and 30% with respect to the mass of the sand. For the characterization of the concrete, the following tests were carried out: water absorption, void index, specific density, compressive strength, flexural tensile strength, modulus of elasticity and microscopy analysis. The incorporation of rubber as aggregate in high-performance concrete proved to be promising for the production of a structural concrete with special characteristics, besides collaborating with the proper disposal of waste tires651110114sem informaçã
Solution of the X-ray edge problem for 2D electrons in a magnetic field
The absorption and emission spectra of transitions between a localized level
and a two-dimensional electron gas, subjected to a weak magnetic field, are
calculated analytically. Adopting the Landau level bosonization technique
developed in previous papers, we find an exact expression for the relative
intensities of spectral lines. Their envelope function, governed by the
interaction between the electron gas and the core hole, is reminescent of the
famous Fermi edge singularity, which is recovered in the limit of a vanishing
magnetic field.Comment: 4 pages, 1 figur
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