538 research outputs found

    A broadband radio study of the average profile and giant pulses from PSR B1821-24A

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    We present the results of wide-band (720-2400 MHz) study of PSR B1821-24A (J1824-2452A, M28A), an energetic millisecond pulsar visible in radio, X-rays and gamma-rays. In radio, the pulsar has a complex average profile which spans >85% of the spin period and exhibits strong evolution with observing frequency. For the first time we measure phase-resolved polarization properties and spectral indices of radio emission throughout almost all of the on-pulse window. We combine this knowledge with the high-energy information to compare M28A to other known gamma-ray millisecond pulsars and to speculate that M28A's radio emission originates in multiple regions within its magnetosphere (i.e. both in the slot or outer gaps near the light cylinder and at lower altitudes above the polar cap). M28A is one of the handful of pulsars which are known to emit Giant Pulses (GPs) -- short, bright radio pulses of unknown nature. We report a drop in the linear polarization of the average profile in both windows of GP generation and also a `W'-shaped absorption feature (resembling a double notch), partly overlapping with one of the GP windows. The GPs themselves have broadband spectra consisting of multiple patches with fractional spectral width (Δν/ν\Delta\nu/\nu) of about 0.07. Although our time resolution was not sufficient to resolve the GP structure on the microsecond scale, we argue that GPs from this pulsar most closely resemble the GPs from the main pulse of the Crab pulsar, which consist of a series of narrowband nanoshots.Comment: 16 pages, 8 figures, accepted to Ap

    Mapping growing stock volume and forest live biomass: a case study of the Polissya region of Ukraine

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    Forest inventory and biomass mapping are important tasks that require inputs from multiple data sources. In this paper we implement two methods for the Ukrainian region of Polissya: random forest (RF) for tree species prediction and k-nearest neighbors (k-NN) for growing stock volume and biomass mapping. We examined the suitability of the five-band RapidEye satellite image to predict the distribution of six tree species. The accuracy of RF is quite high: ~99% for forest/non-forest mask and 89% for tree species prediction. Our results demonstrate that inclusion of elevation as a predictor variable in the RF model improved the performance of tree species classification. We evaluated different distance metrics for the k-NN method, including Euclidean or Mahalanobis distance, most similar neighbor (MSN), gradient nearest neighbor, and independent component analysis. The MSN with the four nearest neighbors (k = 4) is the most precise (according to the root-mean-square deviation) for predicting forest attributes across the study area. The k-NN method allowed us to estimate growing stock volume with an accuracy of 3 m3 ha−1 and for live biomass of about 2 t ha−1 over the study area

    “DEUTSCHE WELLE” AS A MASS MEDIA LANGUAGE FOR SPECIALIST PURPOSES: PRAGMATICS, ANALYSIS, AND TRANSLATION

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    Purpose: Within the framework of the translation studies, the results of research on mass media texts were presented only by individual examples in the professional literature. While, for example, literary texts have developed a variety of guidelines, strategies, and models of translation. There were almost no studies on the TV news translation. We have found only a few references to this topic in scientific works dealing with mass media texts translation in general. There is still no comprehensive analysis of the German mass media translation in Ukrainian. Methodology: However the language for specialist purposes is a special style, which creates and presents to the viewer the news texts for television. Typically, the TV news services set their own requirements for the TV news language, but there are common rules followed by all TV news editors. The linguistic designing defines the light in which the events are presented and what opinion the recipient will form. Result: However, in recent years the demand for mass media texts translation has significantly increased. It was influenced by the distribution of audiovisual international information channels such as Euronews, BBC, France 24, DW. Deutsche Welle TV news which is currently being translated into thirty languages of the world, including Ukrainian. To some degree the translation of Deutsche Welle TV news into Ukrainian influences the level of Ukrainian integration into the European space. Due to a well-executed translation Ukrainians can learn about current political and economic events that take place in Europe and in the world, about the latest achievements in medicine, technology, ecology, sociology, etc. Applications: This research can be used for universities, teachers, and students. Novelty/Originality: In this research, the model of “Deutsche Welle” as a Mass Media Language for Specialist Purposes: Pragmatics, Analysis and Translation is presented in a comprehensive and complete manner

    ESTIMATION OF TRIP MODE PROBABILITY CHOICE USING MULTINOMIAL LOGISTIC MODEL

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    The step of modal split of the four step model for determination of urban travel demand is analyzed. Utility functions are composed, their coefficients are calibrated in TransCAD. Equations for estimation of trip mode choice probability are shown and the numerical illustration of estimation is given

    Deep-learning approach for large atomic structure calculations

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    High-precision atomic structure calculations require accurate modelling of electronic correlations involving large multiconfiguration wave function expansions. Here we develop a deep-learning approach which allows to preselect the most relevant configurations out of large basis sets until the targeted precision is achieved. Our method replaces a large multiconfiguration Dirac-Hartree-Fock computation by a series of smaller ones performed on an iteratively expanding basis subset managed by a convolutional neural network. The results for several examples with many-electron atoms show that deep learning can significantly reduce the required computational memory and running time and renders possible large-scale computations on otherwise unaccessible basis sets

    Accuracy, User Acceptability, and Safety Evaluation for the FreeStyle Libre Flash Glucose Monitoring System When Used by Pregnant Women with Diabetes.

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    Accuracy of the FreeStyle Libre™ Flash Glucose Monitoring System has not been evaluated in pregnant women with diabetes. The aim of this study was to determine accuracy (compared to self-monitoring of blood glucose [SMBG]), clinical safety, and acceptability of the FreeStyle Libre System when used at home by this population.Seventy-four participants, with type 1 (T1D, n = 24), type 2 (T2D, n = 11), or gestational (n = 39) diabetes, were enrolled across 13 sites (9 in United Kingdom, 4 in Austria). Average gestation was 26.6 ± 6.8 weeks (mean ± standard deviation), age was 30.5 ± 5.1 years, diabetes duration was 13.1 ± 7.3 years for T1D and 3.2 ± 2.5 years for T2D, and 49/74 (66.2%) used insulin to manage their diabetes. Sensors were worn for up to 14 days. Sensor glucose values (masked) were compared with capillary SMBG values (made at least 4 times/day).Clinical accuracy of sensor results versus SMBG results was demonstrated, with 88.1% and 99.8% of results within Zone A and Zones A and B of the Consensus Error Grid, respectively. Overall mean absolute relative difference was 11.8%. Sensor accuracy was unaffected by the type of diabetes, the stage of pregnancy, whether insulin was used, age or body mass index. User questionnaires indicated high levels of satisfaction with sensor wear, system use, and comparison to SMBG. There were no unanticipated device-related adverse events.Good agreement was demonstrated between the FreeStyle Libre System and SMBG. Accuracy of the system was unaffected by patient characteristics, indicating that the system is safe and accurate to use by pregnant women with diabetes

    Review of overall parameters of giant radio pulses from the Crab pulsar and B1937+21

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    We present a review of observed parameters of giant radio pulses, based on the observations conducted by our group during recent years. The observations cover a broad frequency range of about 3 octaves, concentrating between 600 and 4850 MHz. Giant pulses of both the Crab pulsar and the millisecond pulsar B1937+21 were studied with the 70-m Tidbinbilla, the 100-m GBT, 64-m Kalyazin and Westerbork radio telescopes. We discuss pulse energy distribution, dependence of peak flux density from the pulse width, peculiarities of radio spectra, and polarization properties of giant radio pulses.Comment: 3 pages, 4 figures, to be published in the Proceedings of the conference "40 Years of Pulsars: Millisecond Pulsars, Magnetars, and More" held on August 12-17, 2007, McGill University, Montreal, Canad
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