Gluon and Ghost Dynamics from Lattice QCD

The two point gluon and ghost correlation functions and the three gluon vertex are investigated, in the Landau gauge, using lattice simulations. For the two point functions, we discuss the approach to the continuum limit looking at the dependence on the lattice spacing and volume. The analytical structure of the propagators is also investigated by computing the corresponding spectral functions using an implementation of the Tikhonov regularisation to solve the integral equation. For the three point function we report results when the momentum of one of the gluon lines is set to zero and discuss its implications.Comment: Proceedings of Light Cone 2016, held in Lisbon, September 2016. Minor changes in text. To appear in Few B Sy

Melhoria da produtividade da clementina ‘Fina’, no Algarve.

A clementina ‘Fina’ é uma das tangerineiras mais cultivadas no Algarve. A baixa produtividade e o pequeno tamanho dos frutos deste cultivar, limitam os rendimentos do citricultor. Na tentativa de melhorar a produtividade desta clementina, foi realizado um ensaio, num pomar comercial, onde se estudou o efeito de aplicações hormonais de GA3 e de GA3+2,4-D. A aplicação de GA3 em plena floração aumentou o número de frutos vingados e provocou uma pequena redução do seu tamanho. O tratamento com GA3 +2,4-D reduziu o número de frutos vingados, em relação ao tratamento com GA3, mas estimulou o crescimento do fruto e aumentou o seu tamanho final. Podemos concluir que, no nosso ensaio, a aplicação conjunta de GA3 e 2,4-D constituiu o tratamento mais eficaz, na melhoria da produtividade da clementina ‘Fina’

Concept for a Time-of-Flight Small Angle Neutron Scattering Instrument at the European Spallation Source

A new Small Angle Neutron Scattering instrument is proposed for the European Spallation Source. The pulsed source requires a time-of-flight analysis of the gathered neutrons at the detector. The optimal instrument length is found to be rather large, which allows for a polarizer and a versatile collimation. The polarizer allows for studying magnetic samples and incoherent background subtraction. The wide collimation will host VSANS and SESANS options that increase the resolution of the instrument towards um and tens of um, respectively. Two 1m2 area detectors will cover a large solid angle simultaneously. The expected gains for this new instrument will lie in the range between 20 and 36, depending on the assessment criteria, when compared to up-to-date reactor based instruments. This will open new perspectives for fast kinetics, weakly scattering samples, and multi-dimensional contrast variation studies.Comment: 18 pages, 10 figure

Statistical mixing and aggregation in Feller diffusion

We consider Feller mean-reverting square-root diffusion, which has been applied to model a wide variety of processes with linearly state-dependent diffusion, such as stochastic volatility and interest rates in finance, and neuronal and populations dynamics in natural sciences. We focus on the statistical mixing (or superstatistical) process in which the parameter related to the mean value can fluctuate - a plausible mechanism for the emergence of heavy-tailed distributions. We obtain analytical results for the associated probability density function (both stationary and time dependent), its correlation structure and aggregation properties. Our results are applied to explain the statistics of stock traded volume at different aggregation scales.Comment: 16 pages, 3 figures. To be published in Journal of Statistical Mechanics: Theory and Experimen

Inverse Low Gain Avalanche Detectors (iLGADs) for precise tracking and timing applications

Low Gain Avalanche Detector (LGAD) is the baseline sensing technology of the recently proposed Minimum Ionizing Particle (MIP) end-cap timing detectors (MTD) at the Atlas and CMS experiments. The current MTD sensor is designed as a multi-pad matrix detector delivering a poor position resolution, due to the relatively large pad area, around 1 $mm^2$; and a good timing resolution, around 20-30 ps. Besides, in his current technological incarnation, the timing resolution of the MTD LGAD sensors is severely degraded once the MIP particle hits the inter-pad region since the signal amplification is missing for this region. This limitation is named as the LGAD fill-factor problem. To overcome the fill factor problem and the poor position resolution of the MTD LGAD sensors, a p-in-p LGAD (iLGAD) was introduced. Contrary to the conventional LGAD, the iLGAD has a non-segmented deep p-well (the multiplication layer). Therefore, iLGADs should ideally present a constant gain value over all the sensitive region of the device without gain drops between the signal collecting electrodes; in other words, iLGADs should have a 100${\%}$ fill-factor by design. In this paper, tracking and timing performance of the first iLGAD prototypes is presented.Comment: Conference Proceedings of VCI2019, 15th Vienna Conference of Instrumentation, February 18-22, 2019, Vienna, Austri

Corporate social responsibility, job satisfaction, and customer orientation in Angola

This study sought to examine the effect of corporate social responsibility (CSR) on employees' costumer orientation through the mediating role of job satisfaction for a sample of tourism and hospitality employees in Angola. Data were collected from 125 respondents using anonymously completed structured questionnaires. Perceived CSR was assessed by the scale developed by Martínez et al. (2013), which includes social, economic and environmental issues. Job satisfaction was measured using Lima et al.'s (1994) job-facet scale, while customer orientation was evaluated using a reduced version of Saxe and Weitz's (1982) customer-orientation scale. The three dimensions of CSR in question have dissimilar levels of association with customer orientation. Only perceptions of company engagement in social CSR practices explain employees' customer orientation, and the relationship is partially mediated by job satisfaction. Additional studies with larger samples and longitudinal designs are needed to determine further the influence of CSR on employees' job satisfaction and customer orientation.info:eu-repo/semantics/acceptedVersio

Evaluation of areas prepared for planting using LANDSAT data

Three different algorithms (SINGLE-CELL, MAXVER and MEDIA K) were used to automatically interpret data from LANDSAT observations of an area of Ribeirao Preto, Brazil. Photographic transparencies were obtained, projected and visually interpreted. The results show that: (1) the MAXVER algorithm presented a better classification performance; (2) verification of the changes in cultivated areas using data from the three different acquisition dates was possible; (3) the water bodies, degraded lands, urban areas, and fallow fields were frequently mistaken by cultivated soils; and (4) the use of projected photographic transparencies furnished satisfactory results, besides reducing the time spent on the image-100 system

Bipolar HII regions - Morphology and star formation in their vicinity - I - G319.88++00.79 and G010.32−-00.15

Our goal is to identify bipolar HII regions and to understand their morphology, their evolution, and the role they play in the formation of new generations of stars. We use the Spitzer and Herschel Hi-GAL surveys to identify bipolar HII regions. We search for their exciting star(s) and estimate their distances using near-IR data. Dense clumps are detected using Herschel-SPIRE data. MALT90 observations allow us to ascertain their association with the central HII region. We identify Class 0/I YSOs using their Spitzer and Herschel-PACS emissions. These methods will be applied to the entire sample of candidate bipolar HII regions. This paper focuses on two bipolar HII regions, one interesting in terms of its morphology, G319.88$+$00.79, and one in terms of its star formation, G010.32$-$00.15. Their exciting clusters are identified and their photometric distances estimated to be 2.6 kpc and 1.75 kpc, respectively. We suggest that these regions formed in dense and flat structures that contain filaments. They have a central ionized region and ionized lobes perpendicular to the parental cloud. The remains of the parental cloud appear as dense (more than 10^4 per cm^3) and cold (14-17 K) condensations. The dust in the PDR is warm (19-25 K). Dense massive clumps are present around the central ionized region. G010.32-00.14 is especially remarkable because five clumps of several hundred solar masses surround the central HII region; their peak column density is a few 10^23 per cm^2, and the mean density in their central regions reaches several 10^5 per cm^3. Four of them contain at least one massive YSO; these clumps also contain extended green objects and Class II methanol masers. This morphology suggests that the formation of a second generation of massive stars has been triggered by the central bipolar HII region. It occurs in the compressed material of the parental cloud.Comment: 32 pages, 28 figures, to be published in A&

Economic assessment of a public DC charging station for electric vehicles with load shift capability

This paper presents a new concept of public DC fast charging station for Electric Vehicles (EVs) with load shift capability and simplified interface with renewable energy sources. The key element of the proposed charging system consists in an Energy Storage System (ESS) composed by reused electrochemical batteries from EVs. In the proposed system the energy storage capability is used to smooth the intermittent power demand of fast charging systems for EV batteries, present in public charging stations, and also contributes to the stability of the electrical power grid. When integrated in a Smart Grid, the proposed system may even return some of the energy stored in the EVs batteries back to the power grid, always when it is necessary, in order to improve the power grid operation. In addition to these technical advantages, the proposed topology also presents some interesting economic benefits that are analyzed along the paper.FCT – Fundação para a Ciência e Tecnologiainfo:eu-repo/semantics/publishedVersio