363 research outputs found
Polyphenol oxidase and pectinmethylesterase enzyme activities in pears after storage in controlled atmospheres
Bimodal Phase Diagram of the Superfluid Density in LaAlO3/SrTiO3 Revealed by an Interfacial Waveguide Resonator
We explore the superconducting phase diagram of the two-dimensional electron
system at the LaAlO3/SrTiO3 interface by monitoring the frequencies of the
cavity modes of a coplanar waveguide resonator fabricated in the interface
itself. We determine the phase diagram of the superconducting transition as a
function of temperature and electrostatic gating, finding that both the
superfluid density and the transition temperature follow a dome shape, but that
the two are not monotonically related. The ground state of this 2DES is
interpreted as a Josephson junction array, where a transition from long- to
short-range order occurs as a function of the electronic doping. The synergy
between correlated oxides and superconducting circuits is revealed to be a
promising route to investigate these exotic compounds, complementary to
standard magneto-transport measurements.Comment: 5 pages, 4 figures and 10 pages of supplementary materia
Characterization of functional single jersey knitted fabrics using non-conventional yarns for sportswear
Eight functional single jersey plain knitted fabrics have been developed in order to assess a quantitative analysis of various
comfort-related properties in terms of thermal control, air and water vapor permeability, wickability, coefficient of
kinetic friction and antimicrobial efficiency, using eight different commercially available functional yarns: Polyester
Craque and viscose Craque conventional yarns as controls; Finecool and Coolmax polyester yarns for moisture
management and quick drying; Holofiber polyester yarns containing an optical responsive material that the producer
claims to improve body oxygenation; Airclo polyester hollow yarns for efficient control of body temperature; and,
finally, polyester Trevira and viscose Seacell for antimicrobial activity. According to the results, Coolmax for moisture
management, Airclo for thermal control and Seacell for antimicrobial activity present the best performances as
technical textiles for sportswear for the respective specific functional property.The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Jefferson M Souza acknowledges CAPES Foundation, Ministry of Education of Brazil (Proc. n 8976/13-9). Andrea Zille acknowledges FCT funding from Programa Compromisso para a Ciência 2008, Portugal, FEDER funding from the Programa Operacional Factores de Competitividade-COMPETE and national funds through FCT – Foundation for Science and Technology within the scope of the projects POCI-01-0145-FEDER-007136 and UID/CTM/00264
How good are RGB cameras retrieving colors of natural scenes and paintings?—A study based on hyperspectral imaging
RGB digital cameras (RGB) compress the spectral information into a trichromatic system capable of approximately representing the actual colors of objects. Although RGB digital cameras follow the same compression philosophy as the human eye (OBS), the spectral sensitivity is different. To what extent they provide the same chromatic experiences is still an open question, especially with complex images. We addressed this question by comparing the actual colors derived from spectral imaging with those obtained with RGB cameras. The data from hyperspectral imaging of 50 natural scenes and 89 paintings was used to estimate the chromatic differences between OBS and RGB. The corresponding color errors were estimated and analyzed in the color spaces CIELAB (using the color difference formulas ΔE*ab and CIEDE2000), Jzazbz, and iCAM06. In CIELAB the most frequent error (using ΔE*ab) found was 5 for both paintings and natural scenes, a similarity that held for the other spaces tested. In addition, the distribution of errors across the color space shows that the errors are small in the achromatic region and increase with saturation. Overall, the results indicate that the chromatic errors estimated are close to the acceptance error and therefore RGB digital cameras are able to produce quite realistic colors of complex scenarios.This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the
framework of the Strategic Funding UIDB/04650/2020
Characterization and analysis of filled knitted fabric formworks for advanced manufacturing of composite structures
An alternative construction methodology has been raising interest, consisting of employing fabrics as formworks. The implementation of flexible formworks allows the production of highly optimized organic structures, avoiding the use of unnecessary materials and consequently reducing construction loads, costs and waste. This study aims to integrate the experimental characterization of the mechanical behaviour of the knitted textiles used as formworks, the mechanical and deformational behaviour of the formworks while being filled with fresh mortar, and the numerical simulation of the multi-step process leading to the final structure. The integration of these different processes is essential for a sound design of this composite system as a construction strategy. To this end, this investigation identified several aspects, related to either experimental or computational mechanics that are relevant to the topic and should be further investigated, with the aim of a future integrated material and structural design approach.ERDF -European Regional Development Fund(undefined
Contributo para a inventariação da biodiversidade marinha da ilha de Santa Maria
XIV Expedição CientÃfica do Departamento de Biologia - Santa Maria 2009.Na XIV Expedição Cientifica à ilha de Santa Maria 2009, organizada pelo Departamento de Biologia da Universidade dos Açores, foram realizados vários trabalhos em diversos locais do litoral da ilha, tendo como objectivo o registo, recolha e identificação de espécies marinhas, tendo sido feita amostragem de fauna e flora intertidal e subtidal (em mergulho com escafandro autónomo). Em cada um dos locais de amostragem procedeu-se a identificação dos exemplares in loco e quando esta não era possÃvel, os indivÃduos foram colectados para posterior identificação em laboratório. Em paralelo, colectaram-se algas e crustáceos decápodes para análise genética (sequenciação de DNA; COI). Foram ainda
efectuados dois arrastos para recolha de plâncton. Toda a informação obtida irá ser incluÃda na base de dados Atlantis. Os trabalhos efectuados inserem-se no âmbito de vários projectos em curso no Departamento de Biologia da UAç (e.g. LusoMarBol, Inspect). A inventariação de espécies resultou no acréscimo de 18 registos à lista de espécies costeiras e marinhas anteriormente referenciadas para Santa Maria, contribuindo deste modo para um melhor conhecimento da biodiversidade costeira e marinha da ilha de Santa Maria
Probing the properties of convective cores through g modes: high-order g modes in SPB and gamma Doradus stars
In main sequence stars the periods of high-order gravity modes are sensitive
probes of stellar cores and, in particular, of the chemical composition
gradient that develops near the outer edge of the convective core. We present
an analytical approximation of high-order g modes that takes into account the
effect of the mu gradient near the core. We show that in main-sequence models,
similarly to the case of white dwarfs, the periods of high-order gravity modes
are accurately described by a uniform period spacing superposed to an
oscillatory component. The periodicity and amplitude of such component are
related, respectively, to the location and sharpness of the mu gradient.
We investigate the properties of high-order gravity modes for stellar models
in a mass domain between 1 and 10 Msun, and the effects of the stellar mass,
evolutionary state, and extra-mixing processes on period spacing features. In
particular, we show that for models of a typical SPB star, a chemical mixing
that could likely be induced by the slow rotation observed in these stars, is
able to significantly change the g-mode spectra of the equilibrium model.
Prospects and challenges for the asteroseismology of gamma Doradus and SPB
stars are also discussed.Comment: 18 pages, 29 figures, accepted for publication in MNRA
Spectrum and Frequency of GJB2 Mutations in a Cohort of 264 Portuguese Nonsyndromic Sensorineural Hearing Loss Patients
OBJECTIVE: To assess the spectrum and prevalence of mutations in the GJB2 gene in Portuguese nonsyndromic sensorineural hearing loss (NSSHL) patients.
DESIGN: Sequencing of the coding region, basal promoter, exon 1, and donor splice site of the GJB2 gene; screening for the presence of the two common GJB6 deletions.
STUDY SAMPLE:
A cohort of 264 Portuguese NSSHL patients.
RESULTS: At least one out of 21 different GJB2 variants was identified in 80 (30.2%) of the 264 patients analysed. Two mutant alleles were found in 53 (20%) of these probands, of which 83% (44/53) harboured at least one c.35delG allele. Twenty-seven (10.2%) of the probands harboured only one mutant allele. Subsequent analysis revealed that the GJB6 deletion del(GJB6-D13S1854) was present in at least 7.4% (2/27) of the patients carrying only one mutant GJB2 allele. Overall, one in five (55/264) of the patients were diagnosed as having DFNB1-related NSSHL, of which the vast majority (53/55) harboured only GJB2 mutations.
CONCLUSIONS: This study provides clear demonstration that mutations in the GJB2 gene are an important cause of NSSHL in Portugal, thus representing a valuable indicator as regards therapeutical and rehabilitation options, as well as genetic counseling of these patients and their families
Improved X-ray detection and particle identification with avalanche photodiodes
Avalanche photodiodes are commonly used as detectors for low energy x-rays.
In this work we report on a fitting technique used to account for different
detector responses resulting from photo absorption in the various APD layers.
The use of this technique results in an improvement of the energy resolution at
8.2 keV by up to a factor of 2, and corrects the timing information by up to 25
ns to account for space dependent electron drift time. In addition, this
waveform analysis is used for particle identification, e.g. to distinguish
between x-rays and MeV electrons in our experiment.Comment: 6 pages, 6 figure
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