Optical and infrared properties of V1647 Orionis during the 2003-2006 outburst. I The reflection nebula

Aims: The recent outburst of the young eruptive star V1647 Orionis has produced a spectacular appearance of a new reflection nebula in Orion (McNeil's nebula). We present an optical/near infrared investigation of McNeil's nebula. This analysis is aimed at determining the morphology, temporal evolution and nature of the nebula and its connection to the outburst. Method: We performed multi epoch B, V, R, I, z, and K imaging of McNeil's nebula and V1647 Ori as well as K_S imaging polarimetry. The multiband imaging allows us to reconstruct the extinction map inside the nebula. Through polarimetric observations we attempt to disentangle the emission from the nebula from that of the accretion disk around V1647 Ori. We also attempt to resolve the small spatial scale structure of the illuminating source. Results: The energy distribution and temporal evolution of McNeil's nebula mimic that of the illuminating source. The extinction map reveals a region of higher extinction in the direction of V1647 Ori. Excluding foreground extionction, the optical extinction due to McNeil's nebula in the direction of V1647 Ori is A_V ~ 6.5 mag. The polarimetric measurement shows a compact high polarization emission around V1647 Ori. The percentage of K_S band linear polarization goes from 10 -- 20 %. The vectors are all well aligned with a position angle of 90 +/- 9 degree East of North. This may correspond to the orientation of a possible accretion disk around V1647 Ori. These findings suggest that the appearance of McNeil's nebula is due to reflection of light by pre-existing material in the surroundings of V1647 Ori. We also report on the discovery of a new candidate brown dwarf or protostar in the vicinity of V1647 Ori as well as the presence of clumpy structure within HH 22A.Comment: 8 pages, 7 figures, in pres

The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST)

(abridged:) The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST) surveys the most populated ~5 square degrees of the Taurus star formation region, using the XMM-Newton X-ray observatory to study the thermal structure, variability, and long-term evolution of hot plasma, to investigate the magnetic dynamo, and to search for new potential members of the association. Many targets are also studied in the optical, and high-resolution X-ray grating spectroscopy has been obtained for selected bright sources. The X-ray spectra have been coherently analyzed with two different thermal models (2-component thermal model, and a continuous emission measure distribution model). We present overall correlations with fundamental stellar parameters that were derived from the previous literature. A few detections from Chandra observations have been added. The present overview paper introduces the project and provides the basic results from the X-ray analysis of all sources detected in the XEST survey.Comprehensive tables summarize the stellar properties of all targets surveyed. The survey goes deeper than previous X-ray surveys of Taurus by about an order of magnitude and for the first time systematically accesses very faint and strongly absorbed TMC objects. We find a detection rate of 85% and 98% for classical and weak-line T Tau stars (CTTS resp. WTTS), and identify about half of the surveyed protostars and brown dwarfs. Overall, 136 out of 169 surveyed stellar systems are detected. We describe an X-ray luminosity vs. mass correlation, discuss the distribution of X-ray-to-bolometric luminosity ratios, and show evidence for lower X-ray luminosities in CTTS compared to WTTS. Detailed analysis (e.g., variability, rotation-activity relations, influence of accretion on X-rays) will be discussed in a series of accompanying papers.Comment: 75 pg, 77 figs. Accepted by A&A, to appear in a special section/issue dedicated to the XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST). V2: ASCII Table 14 added. Version with higher resolution figures at http://www.issibern.ch/teams/Taurus/papers.html or http://www.astro.phys.ethz.ch/papers/guedel/guedel_p_nf.htm

Evaluation of Biogas Unit Operation

Předkládaná bakalářská práce je zaměřena na analyzování ročního provozu bioplynové stanice ve Všerubech. Jsou popsány vstupní suroviny a výstupní produkty a zhodnocena efektivnost celého procesu.Katedra elektroenergetiky a ekologieObhájenoThis bachelor?s thesis is focused on analyzing the annual operation of biogas plants in Všeruby. Is described feedstock and output products and evaluated the effectiveness of the process

Usage of solid waste from biogas power plant to produce energy

Předkládaná diplomová práce je zaměřena na využití odpadního tepla z bioplynové stanice k sušení digestátu a jeho následnému zpracování. Situace je aplikována na konkrétní bioplynovou stanici.Katedra elektroenergetiky a ekologieObhájenoThe master theses focuses on the use of waste heat from biogas power plants to dry the digestate and its subsequent processing. The situation is applied to the specific biogas power plant

Návrh otvírky a přípravy 40.sloje ve 4.kře Dolu Lazy

Import 12/01/2009Prezenční542 - Institut hornického inženýrství a bezpečnostiNeuveden

The Proposal of a Development Work, Preparing and Mining of Natan's Seam, Located in the Block 9 of the Mining Plant Lazy of the Karvina Mine.

Import 29/09/2010Ve své diplomové práci se zabývám návrhem otvírky, přípravy a dobývání 9. kry sloje č. 463 ,,NATAN“, dolu Karviná, závodu Lazy, konkrétněji pak oblasti porubu 163 902. Cílem práce bylo navrhnout vhodnou technologii, pro co nejefektivnější vydobytí daného porubu a následně celé 9 kry. Při návrhu řešení vhodné technologie bylo využito nového strojního vybavení, kterým byl závod Lazy vybaven, díky investičního programu optimalizace produktivity POP 2010. Diplomová práce se dále zabývá řešením problematiky větrání, bezpečnostními opatřeními a technickoekonomickým zhodnocením předloženého návrhu.The thesis is focussed on a proposal of the opening, the preparation and the mining of the ninth mining block of the seam no. 463 called Natan, the coalface area 163 902 of Karviná Mine, Lazy Plant. The main goal is to suggest a suitable technology for the most efficient coalface mined out following the ninth block mined out. Thanks to the productivity optimalization investment programm POP 2010 Lazy Plant was equiped with a new machinery and this machinery has been used to a solving proposal of the suitable technology. The thesis also describes a ventilation solution, the safety instructions and a technical-economic evaluation of the submitted proposal.Prezenční542 - Institut hornického inženýrství a bezpečnostivýborn

Analyticka studie vybranych leciv s vyuzitim kapalinove chromatografie

Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

The role of trade in the greenhouse gas footprints of EU diets

International trade presents a challenge for measuring the greenhouse gas (GHG) emission footprint of human diets, because imported food is produced with different production efficiencies and sourcing regions differ in land use histories. We analyze how trade and countries of origin impact GHG footprint calculation for EU food consumption. We find that food consumption footprints can differ considerably between the EU countries with estimates varying from 610 to 1460 CO2-eq. cap−1 yr−1. These estimates include the GHG emissions from primary production, international trade and land use change. The share of animal products in the diet is the most important factor determining the footprint of food consumption. Embedded land use change in imports also plays a major role. Transition towards more plant-based diets has a great potential for climate change mitigation.Peer reviewe

Dynamics of Tryptophan Metabolic Pathways in Human Placenta and Placental-Derived Cells: Effect of Gestation Age and Trophoblast Differentiation.

L-Tryptophan is an essential amino acid and a precursor of several physiologically active metabolites. In the placenta, the serotonin and kynurenine metabolic pathways of tryptophan metabolism have been identified, giving rise to various molecules of neuroactive or immunoprotective properties, such as serotonin, melatonin, kynurenine, kynurenic acid, or quinolinic acid. Current literature suggests that optimal levels of these molecules in the fetoplacental unit are crucial for proper placenta functions, fetal development and programming. Placenta is a unique endocrine organ that, being equipped with a battery of biotransformation enzymes and transporters, precisely orchestrates homeostasis of tryptophan metabolic pathways. However, because pregnancy is a dynamic process and placental/fetal needs are continuously changing throughout gestation, placenta must adapt to these changes and ensure proper communication in the feto-placental unit. Therefore, in this study we investigated alterations of placental tryptophan metabolic pathways throughout gestation. Quantitative polymerase chain reaction (PCR) analysis of 21 selected genes was carried out in first trimester (n = 13) and term (n = 32) placentas. Heatmap analysis with hierarchical clustering revealed differential gene expression of serotonin and kynurenine pathways across gestation. Subsequently, digital droplet PCR, Western blot, and functional analyses of the rate-limiting enzymes suggest preferential serotonin synthesis early in pregnancy with a switch to kynurenine production toward term. Correspondingly, increased function and/or protein expression of serotonin degrading enzyme and transporters at term indicates efficient placental uptake and metabolic degradation of serotonin. Lastly, gene expression analysis in choriocarcinoma-derived cell lines (BeWo, BeWo b30, JEG-3) revealed dissimilar expression patterns and divergent effect of syncytialization compared to primary trophoblast cells isolated from human term placentas; these findings show that the commonly used in vitro placental models are not suitable to study placental handling of tryptophan. Altogether, our data provide the first comprehensive evidence of changes in placental homeostasis of tryptophan and its metabolites as a function of gestational age, which is critical for proper placental function and fetal development

Profiling of Tryptophan Metabolic Pathways in the Rat Fetoplacental Unit during Gestation

Placental homeostasis of tryptophan is essential for fetal development and programming. The two main metabolic pathways (serotonin and kynurenine) produce bioactive metabolites with immunosuppressive, neurotoxic, or neuroprotective properties and their concentrations in the fetoplacental unit must be tightly regulated throughout gestation. Here, we investigated the expression/function of key enzymes/transporters involved in tryptophan pathways during mid-to-late gestation in rat placenta and fetal organs. Quantitative PCR and heatmap analysis revealed the differential expression of several genes involved in serotonin and kynurenine pathways. To identify the flux of substrates through these pathways, Droplet Digital PCR, western blot, and functional analyses were carried out for the rate-limiting enzymes and transporters. Our findings show that placental tryptophan metabolism to serotonin is crucial in mid-gestation, with a subsequent switch to fetal serotonin synthesis. Concurrently, at term, the close interplay between transporters and metabolizing enzymes of both placenta and fetal organs orchestrates serotonin homeostasis and prevents hyper/hypo-serotonemia. On the other hand, the placental production of kynurenine increases during pregnancy, with a low contribution of fetal organs throughout gestation. Any external insult to this tightly regulated harmony of transporters and enzymes within the fetoplacental unit may affect optimal in utero conditions and have a negative impact on fetal programming