455 research outputs found
Polarized Diffuse Emission at 2.3 GHz in a High Galactic Latitude Area
Polarized diffuse emission observations at 2.3 GHz in a high Galactic
latitude area are presented. The 2\degr X 2\degr field, centred in
(\alpha=5^h,\delta=-49\degr), is located in the region observed by the
BOOMERanG experiment. Our observations has been carried out with the Parkes
Radio telescope and represent the highest frequency detection done to date in
low emission areas. Because of a weaker Faraday rotation action, the high
frequency allows an estimate of the Galactic synchrotron contamination of the
Cosmic Microwave Background Polarization (CMBP) that is more reliable than that
done at 1.4 GHz. We find that the angular power spectra of the E- and B-modes
have slopes of \beta_E = -1.46 +/- 0.14 and \beta_B = -1.87 +/- 0.22,
indicating a flattening with respect to 1.4 GHz. Extrapolated up to 32 GHz, the
E-mode spectrum is about 3 orders of magnitude lower than that of the CMBP,
allowing a clean detection even at this frequency. The best improvement
concerns the B-mode, for which our single-dish observations provide the first
estimate of the contamination on angular scales close to the CMBP peak (about 2
degrees). We find that the CMBP B-mode should be stronger than synchrotron
contamination at 90 GHz for models with T/S > 0.01. This low level could move
down to 60-70 GHz the optimal window for CMBP measures.Comment: 5 pages, 6 figures, accepted for publication in MNRAS Letter
A Portable Sers Method For The Determination Of Uric Acid Using A Paper-based Substrate And Multivariate Curve Resolution.
This paper presents a portable quantitative method for the on-site determination of uric acid in urine using surface-enhanced Raman spectroscopy (SERS) and gold nanoparticle-coated paper as a substrate. A procedure was developed for the rapid preparation of cost-effective SERS substrates that enabled the adequate control of a homogeneous active area and the use of small quantities of gold nanoparticles per substrate. The standard addition method and multivariate curve resolution-alternating least squares (MCR-ALS) were applied to compensate for the matrix effect and to address overlapping bands between uric acid and interference SERS spectra. The proposed methodology demonstrated better performance than conventional univariate methods (in terms of linearity, accuracy and precision), a wide linear range (0-3.5 mmol L(-1)) and an adequate limit of detection (0.11 mmol L(-1)). For the first time, a portable SERS method coupled with chemometrics was developed for the routine analysis of uric acid at clinically relevant concentrations with minimal sample preparation and easy extension for the on-site determination of other biomarkers in complex sample matrices.14
A portable SERS method for the determination of uric acid using a paper-based substrate and multivariate curve resolution
This paper presents a portable quantitative method for the on-site determination of uric acid in urine using surface-enhanced Raman spectroscopy (SERS) and gold nanoparticle-coated paper as a substrate. A procedure was developed for the rapid preparation of cost-effective SERS substrates that enabled the adequate control of a homogeneous active area and the use of small quantities of gold nanoparticles per substrate. The standard addition method and multivariate curve resolution-alternating least squares (MCR-ALS) were applied to compensate for the matrix effect and to address overlapping bands between uric acid and interference SERS spectra. The proposed methodology demonstrated better performance than conventional univariate methods (in terms of linearity, accuracy and precision), a wide linear range (0-3.5 mmol L-1) and an adequate limit of detection (0.11 mmol L-1). For the first time, a portable SERS method coupled with chemometrics was developed for the routine analysis of uric acid at clinically relevant concentrations with minimal sample preparation and easy extension for the on-site determination of other biomarkers in complex sample matrices141619661972CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTĂFICO E TECNOLĂGICO - CNPQsem informaçã
Sardinia radio telescope finite element model updating by means of photogrammetric measurements
The 64 m diameter Sardinia Radio Telescope (SRT), located near Cagliari (Italy), is the worldâs second largest fully
steerable radio telescope with an active surface. Among its peculiarities is the capability of modifying the configuration
of the primary mirror surface by means of electromechanical actuators. This capability enables, within a fixed range,
balancing of the deformation caused by external loads. In this way, the difference between the ideal shape of the mirror
(which maximizes its performance) and the actual surface can be reduced. The control loop of the radio telescope needs
a procedure that is able to predict SRT deformation, with the required accuracy, in order to reduce deviation from the
ideal shape. To achieve this aim, a finite element model that can accurately predict the displacements of the structure is
required. Unfortunately, the finite element model of the SRT, although very refined, does not give completely satisfactory
results, since it does not take into account essential pieces of information, for instance, thermal strains and assembly
defects. This paper explores a possible update of the finite element model using only the benchmark data available,
i.e. the photogrammetric survey developed during the setup of the reflecting surface. This updating leads to a significant
reduction in the differences between photogrammetric data and results of the numerical model. The effectiveness of this
tuning procedure is then assessed
Identifikasi Respon Emosional terhadap Rangsangan Suara melalui Sinyal Elektroensephalogram Menggunakan Wavelet dan Learning Vector Quantization
Emosi merupakan suatu perasaan manusia, seperti senang, sedih, semangat, dan kecewa yang dipengaruhi beberapa faktor seperti cuaca, lingkungan, kesehatan, suara, film, dan video game. Beberapa orang mempunyai kesulitan dalam mengendalikan emosi, biasanya diakibatkan depresi ataupun mengalami gangguan pada syaraf otak. Oleh karena itu diperlukan terapi, yang salah satunya menggunakan rangsangan suara. Keberhasilan terapi ditentukan dari jenis rangsangan suara dan waktu. Oleh karena itu, dibutuhkan identifikasi respon emosional terhadap rangsangan suara secara real time. Salah satu instrumen yang dapat menangkap kondisi emosional adalah Elektroensephalogram (EEG), namun analisisnya tidaklah mudah. Beberapa penelitian terdahulu melakukan identifikasi kondisi rileks, kondisi mental, kewaspadaan, tingkat perhatian melaui sinyal EEG. Identifikasi emosional juga telah dilakukan di antaranya menggunakan Wavelet dan Backpropagation, Wavelet, Support Vector Machine (SVM), dan Frantal Dimension. Namun penelitian tersebut tidak dilakukan secara real time sehingga mempunyai kelemahan memperoleh waktu efektif pemberian terapi jika digunakan untuk evaluasi. Penelitian ini telah membuat sistem diimplementasikan dalam perangkat lunak identifikasi respon emosional secara real time terhadap rangsangan suara dengan segmentasi waktu per 10 detik dalam identifikasinya. Dalam proses akuisisi data dilakukan terhadap 10 naracoba dengan lima kali Perulangan dengan 3 jenis respon yang berbeda yaitu respon semangat. rileks, dan sedih. Hasil pengujian dengan menggunakan seluruh data latih yang sebanyak 2400 menghasilkan akurasi sebesar 93%. Sistem telah diuji dengan menggunakan data baru yang menghasilkan akurasi sebanyak 75%, dan waktu respon 0.0041 detik. Waktu identifikasi cukup cepat dibandingkan waktu identifikasi 10 detik, sehingga dapat digunakan
Detection of pathological lesions in slaughtered rabbits
The slaughterhouse is considered an important control point for the monitoring of rabbit diseases. In our study, 59,440 rabbit carcasses were examined, but only 1% of pathological lesions were recorded at postmortem inspection. Mainly affected were tegumentary, digestive and urinary systems. The most consistent lesion was the subcutaneous abscess; nephritis, probably caused by Encephalitozoon cuniculi, was also frequent. Pathological alterations of the liver, classified as "necrotizing hepatitis" and localized at the caudate lobe, were observed for the first time
A radio-polarisation and rotation measure study of the Gum Nebula and its environment
The Gum Nebula is 36 degree wide shell-like emission nebula at a distance of
only 450 pc. It has been hypothesised to be an old supernova remnant, fossil
HII region, wind-blown bubble, or combination of multiple objects. Here we
investigate the magneto-ionic properties of the nebula using data from recent
surveys: radio-continuum data from the NRAO VLA and S-band Parkes All Sky
Surveys, and H-alpha data from the Southern H-Alpha Sky Survey Atlas. We model
the upper part of the nebula as a spherical shell of ionised gas expanding into
the ambient medium. We perform a maximum-likelihood Markov chain Monte-Carlo
fit to the NVSS rotation measure data, using the H-halpha data to constrain
average electron density in the shell . Assuming a latitudinal background
gradient in RM we find , angular radius
, shell thickness
, ambient magnetic field strength
and warm gas filling factor
. We constrain the local, small-scale (~260 pc)
pitch-angle of the ordered Galactic magnetic field to
, which represents a significant
deviation from the median field orientation on kiloparsec scales
(~-7.2). The moderate compression factor X=6.0\,^{+5.1}_{-2.5} at
the edge of the H-alpha shell implies that the 'old supernova remnant' origin
is unlikely. Our results support a model of the nebula as a HII region around a
wind-blown bubble. Analysis of depolarisation in 2.3 GHz S-PASS data is
consistent with this hypothesis and our best-fitting values agree well with
previous studies of interstellar bubbles.Comment: 33 pages, 16 figures. Accepted by The Astrophysical Journa
Polarization observations in a low synchrotron emission field at 1.4 GHz
We present the first observation of the diffuse polarized synchrotron
radiation of a patch () in the BOOMERanG field,
one of the areas with the lowest CMB foreground emission. The work has been
carried out with the Australia Telescope Compact Array at 1.4 GHz with 3.4
arcmin resolution and sensitivity of mJy beam. The mean
polarized signal has been found to be mK, nearly one order of magnitude below than in the Galactic
Plane.
Extrapolations to frequencies of interest for cosmological investigations
suggest that polarized synchrotron foreground noise should allow the detection
of the CMB Polarization --mode already at 32 GHz and make us confident that,
at 90 GHz, it is accessible with no relevant foreground contamination. Last but
not least, even the --mode detection for is not ruled out in
such a low emission patch.Comment: Uses emulateapj.sty, onecolfloat.sty, 5 pages 4 fig., accepted for
publication in ApJ
A Multi-Physic Modelling Insight into the Differences between Microwave and Conventional Heating for the Synthesis of TiO2 Nanoparticles
Microwave-assisted synthesis of nanoparticles usually leads to a smaller and more uni-formly distributed particle size compared to conventional heating (e.g., oil bath). Numerical simulation can help to obtain a better insight into the process in terms of temperature distribution or to evidence existing different temperature profiles and heating rates between the two techniques. In this paper multi-physics numerical simulation is used to investigate the continuous flow synthesis of titanium oxide nanoparticles starting from alkoxide precursors. Temperature-dependent permit-tivity of reactants has been measured, including the effects of permanence at the maximum synthesis temperature. A temperature homogeneity index has been defined to compare microwave and conventional heating. Results show that when using microwave heating at 2450 MHz, in the inves-tigated conditions, a much higher temperature homogeneity of the reactants is reached. Moreover, reactants experience different heating rates, depending on their position inside the microwave ap-plicator, while this is almost negligible in the case of conventional heating
- âŠ