Near- to mid-infrared spectroscopy of the heavily obscured AGN LEDA 1712304 with AKARI/IRC

Context. Although heavily obscured active galactic nuclei (AGNs) have been found by many observational studies, the properties of the surrounding dust are poorly understood. Using AKARI/IRC spectroscopy, we discover a new sample of a heavily obscured AGN in LEDA 1712304 which shows a deep spectral absorption feature due to silicate dust. Aims. We study the infrared (IR) spectral properties of circumnuclear silicate dust in LEDA 1712304. Methods. We perform IR spectral fitting, considering silicate dust properties such as composition, porosity, size and crystallinity. Spectral energy distribution (SED) fitting is also performed to the flux densities in the UV to sub-millimeter range to investigate the global spectral properties. Results. The best-fit model indicates 0.1 $\mu$m-sized porous amorphous olivine (${\rm Mg_{2x}Fe_{2-2x}SiO_4}$; $x=0.4$) with $4\%$ crystalline pyroxene. The optical depth is $\tau_{\rm sil}{\sim}2.3$, while the total IR luminosity and stellar mass are estimated to be $L_{\rm IR}=(5\pm1){\times}10^{10}\,L_{\odot}$ and $M_{\rm star}=(2.7\pm0.8){\times}10^{9}\,M_{\odot}$, respectively. In such low $L_{\rm IR}$ and $M_{\rm star}$ ranges, there are few galaxies which show that large ${\tau}_{\rm sil}$. Conclusions. The silicate dust in the AGN torus of LEDA 1712304 has properties notably similar to those in other AGNs as a whole, but slightly different in the wing shape of the absorption profile. The porosity of the silicate dust suggests dust coagulation or processing in the circumnuclear environments, while the crystallinity suggests that the silicate dust is relatively fresh.Comment: 9 pages, 6 figures, accepted for publication in A&

Medpor implant in cranioorbitomaxillary reconstruction: institutional experience and a review of the literature

ManuscriptAutologous materials remain the gold standard for complex skull base and craniofacial reconstruction, but they carry additional morbidity associated with the second harvest procedure and with prolonged operation time. These autologous materials also resorb in a way that is not predictable, rendering them less ideal in situations where cosmesis and function are of paramount importance to aid with primary healing of the intracranial wound. Medpor porous polyethylene implant is an alloplastic material with unique characteristics that make it an excellent alternative for cranioorbitomaxillary reconstruction. The porous nature of the implant permits the ingrowth of vascularized tissue eventually forming a highly stable complex resistant to infection and deformation. A total of 698 patients undergoing 719 procedures in which Medpor was implanted were reviewed. Two complications occurred that required removal of the implant. On the basis of our results, we believe that the Medpor implant is an excellent alternative to existing alloplastic materials with a low incidence of infection and excellent cosmetic and functional results

AKARI Detections of Hot Dust in Luminous Infrared Galaxies

We present a new sample of active galactic nuclei (AGNs) identified using the catalog of the AKARI Mid-infrared(MIR) All-Sky Survey. Our MIR search has an advantage in detecting AGNs that are obscured at optical wavelengths due to extinction. We first selected AKARI 9micron excess sources with F(9micron)/F(K_S)>2 where K_S magnitudes were taken from the Two Micron All Sky Survey. We then obtained follow-up near-infrared spectroscopy with the AKARI/IRC, to confirm that the excess is caused by hot dust. We also obtained optical spectroscopy with the Kast Double Spectrograph on the Shane 3-m telescope at Lick Observatory. On the basis of on these observations, we detected hot dust with a characteristic temperature of ~500K in two luminous infrared galaxies. The hot dust is suspected to be associated with AGNs that exhibit their nonstellar activity not in the optical, but in the near- and mid-infrared bands, i.e., they harbor buried AGNs. The host galaxy stellar masses of 4-6 x 10^9 M_sun are small compared with the hosts in optically-selected AGN populations. These objects were missed by previous surveys, demonstrating the power of the AKARI MIR All-Sky Survey to widen AGN searches to include more heavily obscured objects. The existence of multiple dusty star clusters with massive stars cannot be completely ruled out with our current data.Comment: 15 pages, 4 figures, to be published in Astronomy & Astrophysic

Spitzer/IRS Full Spectral Modeling to Characterize Mineralogical Properties of Silicate Dust in Heavily Obscured AGNs

Mid-infrared silicate dust bands observed in heavily obscured active galactic nuclei (AGNs) include information on the mineralogical properties of silicate dust. We aim to investigate the mineralogical picture of the circumnuclear region of heavily obscured AGNs to reveal obscured AGN activities through the picture. In our previous study, we investigated the properties of silicate dust in heavily obscured AGNs, focusing on the mineralogical composition and the crystallinity with Spitzer/IRS 5.3–12 μm spectra. In this study, we model the full-range Spitzer/IRS 5–30 μm spectra of 98 heavily obscured AGNs using a one-dimensional radiative transfer calculation with four dust species in order to evaluate wider ranges of the properties of silicate dust more reliably. Comparing fitting results between four dust models with different sizes and porosities, 95 out of the 98 galaxies prefer a porous silicate dust model without micron-sized large grains. The pyroxene mass fraction and the crystallinity are overall consistent with—but significantly different from—the previous results for the individual galaxies. The pyroxene-poor composition, small dust size, and high porosity are similar to newly formed dust around mass-loss stars as seen in our Galaxy, which presumably originates from the recent circumnuclear starburst activity. The high crystallinity on average suggests dust processing induced by AGN activities

Bloom-epistemic and sentiment analysis hierarchical classification in course discussion forums

Online discussion forums are widely used for active textual interaction between lecturers and students, and to see how the students have progressed in a learning process. The objective of this study is to compare appropriate machine-learning models to assess sentiments and Bloom\'s epistemic taxonomy based on textual comments in educational discussion forums. Our proposed method is called the hierarchical approach of Bloom-Epistemic and Sentiment Analysis (BE-Sent). The research methodology consists of three main steps. The first step is the data collection from the internal discussion forum and YouTube comments of a Web Programming channel. The next step is text preprocessing to annotate the text and clear unimportant words. Furthermore, with the text dataset that has been successfully cleaned, sentiment analysis and epistemic categorization will be done in each sentence of the text. Sentiment analysis is divided into three categories: positive, negative, and neutral. Bloom\'s epistemic is divided into six categories: remembering, understanding, applying, analyzing, evaluating, and creating. This research has succeeded in producing a course learning subsystem that assesses opinions based on text reviews of discussion forums according to the category of sentiment and epistemic analysis.Comment: 11 pages, 7 figure

A study of the selective hydroconversion of biocarboxylic acids to bioalcohols over novel indium-nickel/zeolite catalysts using octanoic acid as model reactant

Octanoic acid (OA) was hydrotreated in a flow-through reactor at 21 bar total pressure and 240-340 °C over supported metal catalysts prepared from Ni-zeolites (A, X, P) by indium modification. The Ni-zeolites were activated first in H2 flow at 21 bar and 450 °C. While a fraction of the nickel got fully reduced, the zeolite structure became partially destructed. However, some nickel cations remained unreduced, therefore a large fraction of the crystalline zeolite structure was retained. The indium modification of the reduced Ni-zeolites generated bimetallic NiIn/Ni,H-zeolite catalysts having higher stability, hydroconversion activity, octanol selectivity, and lower hydrodecarbonylation activity than the parent partially destructed Ni-zeolite and the Adkins-type catalysts, commercially applied for the conversion of fatty acids to alcohols. © 2013 Akadémiai Kiadó, Budapest, Hungary

Proposal of a suitable insurable portfolio for a municipality Budišov

Diplomová práce se zabývá problematikou, která souvisí s návrhem pojistného portfolia pro obec Budišov. Na základě aktiv obce a analýzy rizik je navrhnuto takové pojistné portfolio, díky kterému budou nejzávažnější rizika obce prostřednictvím komerční pojišťovny minimalizována.This diploma thesis deals with the problems related to insurance protection for municipality Budišov. The insurance portfolio is suggested on the basis of municipality assets and analysis of all risks. It helps to minimize the most serious risks of its activities through the commercial insurance company.