5,121 research outputs found
Clear detection of dusty torus signatures in a Weak-Line Radio Galaxy: the case of PKS 0043-42
We report the clearest detection to date of dusty torus signatures in a
Weak-Line Radio Galaxy (WLRG). The deep Spitzer InfraRed Spectrograph (IRS)
rest-frame mid-infrared (MIR) spectrum of the WLRG PKS 0043-42 (z=0.116) shows
a clear spectral turnover at wavelengths longer than ~20 micron suggestive of
warm dust, as well as a 9.7 micron silicate absorption feature. In addition,
the hard X-ray results, based on Chandra data, strongly support a picture in
which PKS 0043-42 has a torus and accretion disc more typical of Strong-Line
Radio Galaxies (SLRGs). The MIR and X-ray spectra are markedly different from
those of other WLRGs at similar redshifts, and here we show that the former can
be successfully fitted with clumpy torus models with parameters characteristic
of Type-2 AGN tori: close to edge-on (i=74 deg) and relatively broad (torus
angular width=60 deg), with an outer radius of 2 pc, hydrogen column density
~1.6x10^(23) cm^(-2), and AGN bolometric luminosity ~1.6x10^(44) erg s^(-1).
The presence of a compact torus in PKS 0043-42 provides evidence that this WLRG
is fuelled by cold, rather than hot, gas accretion. We suggest that WLRGs are a
diverse population, and PKS 0043-42 may represent a type of radio galaxy in
which the AGN activity has been recently re-triggered as a consequence of
intermittent gas supply, or in which the covering factor of the Narrow-Line
Region (NLR) clouds is relatively low.Comment: 7 pages, 6 figures, 1 table. Accepted by MNRA
Social construction of information technology supporting work
In the beginning of 1999, the CIO of a Portuguese company in the automobile industry was
debating with himself whether to abandon or to continue supporting the MIS his company had
been using for years. This MIS had been supporting the company’s production processes and
the procurement of resources for these processes. However, in spite of the fact that the MIS
system had been deployed under the CIO’s tight control, the CIO felt strong opposition to the
use of this MIS system, opposition that was preventing the MIS system from being used to its full
potential. Moreover, the CIO was at lost as to how to ensure greater compliance to his control
and fuller use of the MIS system. Therefore, the CIO decided that he needed someone external
to the company to help him understand the fundamental reasons, technical, social, or cultural,
for the opposition to the MIS system
Towards energy-autonomous wake-up receiver using visible light communication
The use of Visible Light Communication (VLC) in wake-up communication systems is a potential energy-efficient and low-cost solution for wireless communication of consumer electronics. In this paper, we go one step further and propose the use of visible light both for wake-up communication and energy harvesting purposes, with the final objective of an energy-autonomous wake-up receiver module. We first present the details and the design criteria of this novel system. We then present the results of evaluation of design criteria such as solar panel and capacitor type choices. To evaluate the performance of the developed wake-up system with energy-autonomous receiver system, we perform realistic indoor scenario tests, analyzing the effect of varying distances, angles, and light intensities as well as the effect of presence of interfering lights.Peer ReviewedPostprint (author's final draft
Unconventional Strong Spin-Fluctuation Effects around the Critical Pressure of the Itinerant Ising-Type Ferromagnet URhAl
Resistivity measurements were performed for the itinerant Ising-type
ferromagnet URhAl at temperatures down to 40 mK under high pressure up to 7.5
GPa, using single crystals. We found that the critical pressure of the Curie
temperature exists at around ~ 5.2 GPa. Near , the -coefficient
of the Fermi-liquid resistivity term below is largely enhanced
with a maximum around 5.2-5.5 GPa. Above , the exponent of the resistivity
deviates from 2. At , it is close to , which is
expected by the theory of three-dimensional ferromagnetic spin fluctuations for
a 2nd-order quantum-critical point (QCP). However, disappears as a
1st-order phase transition, and the critical behavior of resistivity in URhAl
cannot be explained by the theory of a 2nd-order QCP. The 1st-order nature of
the phase transition is weak, and the critical behavior is still dominated by
the spin fluctuation at low temperature. With increasing pressure, the
non-Fermi-liquid behavior is observed in higher fields. Magnetic field studies
point out a ferromagnetic wing structure with a tri-critical point (TCP) at ~
4.8-4.9 GPa in URhAl. One open possibility is that the switch from the
ferromagnetic to the paramagnetic states does not occur simply but an
intermediate state arises below the TCP as suggested theoretically recently.
Quite generally, if a drastic Fermi-surface change occurs through , the
nature of the interaction itself may change and lead to the observed
unconventional behavior.Comment: 9 pages, 9 figure
Small bowel tumors detection in capsule endoscopy by gaussian modeling of color curvelet covariance coefficients
This paper is concerned with the classification of tumoral tissue in the small bowel by using capsule endoscopic images. The followed approach is based on texture classification. Texture descriptors are derived from selected scales of the Discrete Curvelet Transform (DCT). The goal is to take advantage of the high directional sensitivity of the DCT (16 directions) when compared with the Discrete Wavelet Transform (DWT) (3 directions). Second order statistics are then computed in the HSV color space and named Color Curvelet Covariance (3C) coefficients. Finally, these coefficients are modeled by a Gaussian Mixture Model (GMM). Sensitivity of 99% and specificity of 95.19% are obtained in the testing set.Centre Algoritm
Big data warehouse framework for smart revenue management
Revenue Management’s most cited definitions is probably “to sell the right accommodation to the
right customer, at the right time and the right price, with optimal satisfaction for customers and hoteliers”.
Smart Revenue Management (SRM) is a project, which aims the development of smart automatic techniques
for an efficient optimization of occupancy and rates of hotel accommodations, commonly referred to, as
revenue management. One of the objectives of this project is to demonstrate that the collection of Big Data,
followed by an appropriate assembly of functionalities, will make possible to generate a Data Warehouse
necessary to produce high quality business intelligence and analytics. This will be achieved through the
collection of data extracted from a variety of sources, including from the web. This paper proposes a three stage
framework to develop the Big Data Warehouse for the SRM. Namely, the compilation of all available
information, in the present case, it was focus only the extraction of information from the web by a web crawler
– raw data. The storing of that raw data in a primary NoSQL database, and from that data the conception of a
set of functionalities, rules, principles and semantics to select, combine and store in a secondary relational
database the meaningful information for the Revenue Management (Big Data Warehouse). The last stage will
be the principal focus of the paper. In this context, clues will also be giving how to compile information for
Business Intelligence. All these functionalities contribute to a holistic framework that, in the future, will make
it possible to anticipate customers and competitor’s behavior, fundamental elements to fulfill the Revenue
Managemen
Motivational Effects of the Perceived Image of Non-governmental Organisations
The motivational effect of the perceived image of non-governmental organisations (NGOs) was analysed in two studies. Results from the first study, comprising two samples (N = 314 and N = 220), point to three dimensions of the perceived image of NGOs (solidarity, misleading and instrumentality). These dimensions have different effects on intention to collaborate and to recommend others to collaborate. In the second study, with a sample of N = 485, confirmatory analysis confirmed the three-factor solution as appropriate. The misleading image emerged as a source of reactance to NGO campaigns. Results suggest the importance of promoting the image of solidarity as a motivational strategy
Requirements specifications and recovered architectures as grounded theories
This paper describes the classic grounded theory (GT) process as a method to discover GTs to be
subjected to later empirical validation. The paper shows that a well conducted instance of
requirements engineering or of architecture recovery resembles an instance of the GT process for
the purpose of discovering the requirements specification or recovered architecture artifact that the
requirements engineering or architecture recovery produces. Therefore, this artifact resembles a
GT
Sucroferric oxyhydroxide for hyperphosphatemia: A review of real-world evidence
Hyperphosphatemia is a common complication in dialysis-dependent patients with chronic kidney disease. Most dialysis-dependent patients need oral phosphate binder therapy to control serum phosphorus concentrations. Most phosphate binders have a high daily pill burden, which may reduce treatment adherence and impair phosphorus control. Sucroferric oxyhydroxide is a potent iron-based phosphate binder approved for use in dialysis-dependent patients in 2013. A randomized controlled trial of sucroferric oxyhydroxide demonstrated its efficacy for reduction of serum phosphorus with a lower pill burden than sevelamer carbonate. Clinical trials carefully select patients, monitor adherence, and routinely titrate medications to a protocol-defined goal. Consequently, trials may not reflect real-world use of medications. Since its approval, we and others have performed retrospective and prospective analyses of sucroferric oxyhydroxide in real-world clinical practice in \u3e 6400 hemodialysis and approximately 500 peritoneal dialysis patients in the USA and Europe. Consistent with the clinical trial data, real-world observational studies have demonstrated that sucroferric oxyhydroxide can effectively reduce serum phosphorus with a lower daily pill burden than most other phosphate binders. These studies have also shown sucroferric oxyhydroxide provides effective serum phosphorus control in different treatment settings, including as monotherapy in phosphate binder-naïve patients, in patients switching from other phosphate binders, or when used in combination with other phosphate binders. These observational studies indicate a favorable safety and tolerability profile, and minimal, if any, systemic iron absorption. This article reviews the key results from these observational studies of sucroferric oxyhydroxide and evaluates its role in the management of hyperphosphatemia in clinical practice
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