26,179 research outputs found

    Probing quantum fluctuation theorems in engineered reservoirs

    Full text link
    Fluctuation Theorems are central in stochastic thermodynamics, as they allow for quantifying the irreversibility of single trajectories. Although they have been experimentally checked in the classical regime, a practical demonstration in the framework of quantum open systems is still to come. Here we propose a realistic platform to probe fluctuation theorems in the quantum regime. It is based on an effective two-level system coupled to an engineered reservoir, that enables the detection of the photons emitted and absorbed by the system. When the system is coherently driven, a measurable quantum component in the entropy production is evidenced. We quantify the error due to photon detection inefficiency, and show that the missing information can be efficiently corrected, based solely on the detected events. Our findings provide new insights into how the quantum character of a physical system impacts its thermodynamic evolution.Comment: 9 pages, 4 figure

    Use of N-Alkanes to Estimate the Intake of Beef Heifers on Natural Grassland in Southern Brazil

    Get PDF
    The technique of alkanes to estimate dry matter intake (DMI) by wild and domestic herbivores has advanced considerably in the last 20 years (Dove and Mayes, 2006). Alkanes are long chain, saturated hydrocarbons present in the plant cuticle. They are relatively indigestible in the gastrointestinal tract and can be recuperated in the faeces. Compared to other markers normally used (e.g. chromium oxide, ytterbium), it is possible to determine simultaneously the external and internal marker in a unique analysis and to estimate digestibility, faecal excretion, DMI and diet composition (Dove and Mayes 1991). This is a great advantage of this technique to support studies of plant-animal interactions in rangeland environments

    Advanced surface characterization of silver nanocluster segregation in Ag-TiCN bioactive coatings by RBS, GDOES and ARXPS

    Get PDF
    Surface modification by means of wear protective and antibacterial coatings represents, nowadays, a crucial challenge in the biomaterials field in order to enhance the lifetime of bio-devices. It is possible to tailor the properties of the material by using an appropriate combination of high wear resistance (e.g., nitride or carbide coatings) and biocide agents (e.g., noble metals as silver) to fulfill its final application. This behavior is controlled at last by the outmost surface of the coating. Therefore, the analytical characterization of these new materials requires high-resolution analytical techniques able to provide information about surface and depth composition down to the nanometric level. Among these techniques are Rutherford backscattering spectrometry (RBS), glow discharge optical emission spectroscopy (GDOES), and angle resolved X-ray photoelectron spectroscopy (ARXPS). In this work, we present a comparative RBS–GDOES–ARXPS study of the surface characterization of Ag–TiCN coatings with Ag/Ti atomic ratios varying from 0 to 1.49, deposited at room temperature and 200 °C. RBS analysis allowed a precise quantification of the silver content along the coating with a non-uniform Ag depth distribution for the samples with higher Ag content. GDOES surface profiling revealed that the samples with higher Ag content as well as the samples deposited at 200 °C showed an ultrathin (1–10 nm) Ag-rich layer on the coating surface followed by a silver depletion zone (20–30 nm), being the thickness of both layers enhanced with Ag content and deposition temperature. ARXPS analysis confirmed these observations after applying general algorithm involving regularization in addition to singular value decomposition techniques to obtain the concentration depth profiles. Finally, ARXPS measurements were used to provide further information on the surface morphology of the samples obtaining an excellent agreement with SEM observations when a growth model of silver islands with a height d = 1.5 nm and coverage θ = 0.20 was applied to the sample with Ag/Ti = 1.49 and deposited at room temperature.This work was financially supported by the Spanish Ministry of Science and Innovation (projects FUNCOAT CSD2008-00023 and RyC2007-0026). This research is sponsored by FEDER funds through the program COMPETE "Programa Operacional Factores de Competitividade" and by national funds through FCT "Fundacao para a Ciencia e a Tecnologia", in the framework of the Strategic Projects PEST-C/FIS/UI607/2011, and PEST-C/EME/UI0285/2011 and under the project PTDC/CTM/102853/2008. The authors would like to acknowledge I. Caretti and R. Velasco for the fruitful discussions and the proofreading of the manuscript

    Efeito de fungicidas e inseticidas em sementes peletizadas de sorgo.

    Get PDF
    Edição dos resumos do 18º Congresso Brasileiro de Sementes, 2013, Florianópolis
    • …
    corecore