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36 result(s) for "DOBES, PETR"
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Automatic camera calibration by landmarks on rigid objects
This article presents a new method for automatic calibration of surveillance cameras. We are dealing with traffic surveillance, and therefore, the camera is calibrated by observing vehicles; however, other rigid objects can be used instead. The proposed method is using keypoints or landmarks automatically detected on the observed objects by a convolutional neural network. By using fine-grained recognition of the vehicles (calibration objects), and by knowing the 3D positions of the landmarks for the (very limited) set of known objects, the extracted keypoints are used for calibration of the camera, resulting in internal (focal length) and external (rotation, translation) parameters and scene scale of the surveillance camera. We collected a dataset in two parking lots and equipped it with a calibration ground truth by measuring multiple distances in the ground plane. This dataset seems to be more accurate than the existing comparable data (GT calibration error reduced from 4.62 % to 0.99 %). Also, the experiments show that our method overcomes the best existing alternative in terms of accuracy (error reduced from 6.56 % to 4.03 % ) and our solution is also more flexible in terms of viewpoint change and other.
Influence of mutation type on prognostic and predictive values of TP53 status in primary breast cancer patients
High rates of mutation in the TP53 tumor suppressor gene have been found in many human cancers, including breast tumors, making p53 one of the most studied proteins in oncology. However, the prognostic and predictive value of alterations in this gene remains ambiguous. To analyze the clinical value of somatic TP53 mutations, we collected clinical and molecular data on 210 women with primary breast cancer. We found significant associations of p53 mutations with tumor grade, metastasis, molecular subtype, Her2 status and inverse correlations with estrogen and progesterone receptor status. Cox proportional hazard analysis confirmed a strong prognostic value of p53 mutation for overall survival rate and highlighted significant interactions with lymph node involvement and tumor size. In relation to treatment options, TP53 mutations were associated with poor response to anthracyclines and radiotherapy. Categorization of TP53 mutations according to their type and location revealed that patients with nonsense mutation have the poorest prognosis in comparison with wild-type cases and other types of mutations in this gene. Classification of TP53 mutations with respect to the degree of disturbance of protein structure showed association of disruptive mutations with poorer patients' outcome in contrast to wild-type and non-disruptive mutations. In conclusion, the present study confirms p53 as a potential predictive and prognostic factor in oncology practice and highlights the growing evidence that distinct types of mutations have different clinical impacts.
Caffeine Inhibits Acetylcholinesterase, But Not Butyrylcholinesterase
Caffeine is an alkaloid with a stimulant effect in the body. It can interfere in transmissions based on acetylcholine, epinephrine, norepinephrine, serotonin, dopamine and glutamate. Clinical studies indicate that it can be involved in the slowing of Alzheimer disease pathology and some other effects. The effects are not well understood. In the present work, we focused on the question whether caffeine can inhibit acetylcholinesterase (AChE) and/or, butyrylcholinesterase (BChE), the two enzymes participating in cholinergic neurotransmission. A standard Ellman test with human AChE and BChE was done for altering concentrations of caffeine. The test was supported by an in silico examination as well. Donepezil and tacrine were used as standards. In compliance with Dixon’s plot, caffeine was proved to be a non-competitive inhibitor of AChE and BChE. However, inhibition of BChE was quite weak, as the inhibition constant, Ki, was 13.9 ± 7.4 mol/L. Inhibition of AChE was more relevant, as Ki was found to be 175 ± 9 µmol/L. The predicted free energy of binding was −6.7 kcal/mol. The proposed binding orientation of caffeine can interact with Trp86, and it can be stabilize by Tyr337 in comparison to the smaller Ala328 in the case of human BChE; thus, it can explain the lower binding affinity of caffeine for BChE with reference to AChE. The biological relevance of the findings is discussed.
The Origin of Synchysite-(Ce) and Sources of Rare Earth Elements in the Rožná Uranium Deposit, Czech Republic
Synchysite was identified in the Rožná uranium deposit in a quartz–carbonate–sulfide vein, which is a part of the late (post-uranium and, post-Variscan) stage of the development of the hydrothermal system. The synchysite forms needles or lamellae, which are almost exclusively bound to the quartz filling of the veins. The structure of the quartz vein-filling, i.e., the preserved tubular syneresis crack pattern, Liesegang bands formed by hematite, chaotic grain size distribution of quartz grains, and ribbons of fibrous SiO2 grains, indicate that the synchysite crystallized in a silica gel. Its formation may be explained by the reaction of hydrothermal acid fluids rich in Fe2+ and rare earth elements (REEs) with alkaline Ca2+ HCO3− and F-rich fluids expelled from the gel during syneresis, or by its ageing. The subsequent recrystallization of the gel to form euhedral quartz grains was accompanied by the deformation of previously formed Liesegang rings, and the development of quartz rosettes. The study of fluid inclusions indicated that the silica gel originated at a very low temperature. The temperatures of the homogenization of two-phase inclusions in carbonate and quartz vein-filling varied between 38 and 74 °C, and the salinity ranged between 4 and 10 wt.% NaCl equiv. The δ13C carbonate values (from −4.65 to −5.21‰, PDB) indicate the deep-seated source of CO2, and δ18O values (from 14.76 to 18.22‰, SMOW) show that the source of the hydrothermal fluids was mainly surface water, with a possible admixture of fossil saline brines. The main sources of REEs are thought to have predominantly been uranium minerals (coffinitized uraninite and coffinite) that form a part of the breccia fragments embedded in the vein filling. The results illustrate the significant mobility of REEs in the late, low-temperature hydrothermal system, and they indicate the multiple remobilizations of REEs in the uranium deposits in general.
Transferable scoring function based on semiempirical quantum mechanical PM6-DH2 method: CDK2 with 15 structurally diverse inhibitors
A semiempirical quantum mechanical PM6-DH2 method accurately covering the dispersion interaction and H-bonding was used to score fifteen structurally diverse CDK2 inhibitors. The geometries of all the complexes were taken from the X-ray structures and were reoptimised by the PM6-DH2 method in continuum water. The total scoring function was constructed as an estimate of the binding free energy, i.e., as a sum of the interaction enthalpy, interaction entropy and the corrections for the inhibitor desolvation and deformation energies. The applied scoring function contains a clear thermodynamical terms and does not involve any adjustable empirical parameter. The best correlations with the experimental inhibition constants (ln K i ) were found for bare interaction enthalpy ( r 2  = 0.87) and interaction enthalpy corrected for ligand desolvation and deformation energies ( r 2  = 0.77); when the entropic term was considered, however, the correlation becomes worse but still acceptable ( r 2  = 0.52). The resulting correlation based on the PM6-DH2 scoring function is better than previously published function based on various docking/scoring, SAR studies or advanced QM/MM approach, however, the robustness is limited by number of available experimental data used in the correlation. Since a very similar correlation between the experimental and theoretical results was found also for a different system of the HIV-1 protease, the suggested scoring function based on the PM6-DH2 method seems to be applicable in drug design, even if diverse protein–ligand complexes have to be ranked.
Multiphase formation of the Obří důl polymetallic skarn deposit, West Sudetes, Bohemian Massif: geochemistry and Re–Os dating of sulfide mineralization
The Obří důl Fe–Cu–As polymetallic sulfide skarn deposit is developed in a metamorphic series in the West Sudetes, Bohemian Massif. It consists of lenses of marble, calc–silicate rocks, and skarns. We studied the Gustav orebody, which is located few hundred meters away from the contact with a large, late-orogenic Variscan Krkonoše–Jizera Plutonic Complex (KJPC) emplaced into shallow crust. Mineralogical and fluid inclusion study evidence indicates that the main sulfide stage, dominated by pyrrhotite, arsenopyrite, and chalcopyrite originated from aqueous hydrothermal fluids with salinity up to 8 wt% NaCl eq. with minimum homogenization temperatures ranging from 324 to 358 °C. These fluids mainly replaced carbonate-rich lithologies. Carbon, oxygen, and strontium isotope data in Ca-rich rocks imply total overprinting by channelized metasomatic fluid flow, which is most probably related to the intrusion of the KJPC, whereas δ34S values of sulfides argue for a magmatic source of sulfur. The Re–Os age of arsenopyrite overlaps published age data for the KJPC and suggests synchronous formation of the main sulfide mineralization and pluton emplacement.
The Rožná uranium deposit (Bohemian Massif, Czech Republic): shear zone-hosted, late Variscan and post-Variscan hydrothermal mineralization
Three major mineralization events are recorded at the Rožná uranium deposit (total mine production of 23,000 t U, average grade of 0.24% U): (1) pre-uranium quartz-sulfide and carbonate-sulfide mineralization, (2) uranium, and (3) post-uranium quartz-carbonate-sulfide mineralization. (1) K–Ar ages for white mica from wall rock alteration of the pre-uranium mineralization style range from 304.5 ± 5.8 to 307.6 ± 6.0 Ma coinciding with the post-orogenic exhumation of the Moldanubian orogenic root and retrograde-metamorphic equilibration of the high-grade metamorphic host rocks. The fluid inclusion record consists of low-salinity aqueous inclusions, together with H 2 O-CO 2 -CH 4 , CO 2 -CH 4 , and pure CH 4 inclusions. The fluid inclusion, paragenetic, and isotope data suggest that the pre-uranium mineralization formed from a reduced low-salinity aqueous fluid at temperatures close to 300°C. (2) The uraniferous hydrothermal event is subdivided into the pre-ore, ore, and post-ore substages. K–Ar ages of pre-ore authigenic K-feldspar range from 296.3 ± 7.5 to 281.0 ± 5.4 Ma and coincide with the transcurrent reorganization of crustal blocks of the Bohemian Massif and with Late Stephanian to Early Permian rifting. Massive hematitization, albitization, and desilicification of the pre-ore altered rocks indicate an influx of oxidized basinal fluids to the crystalline rocks of the Moldanubian domain. The wide range of salinities of fluid inclusions is interpreted as a result of the large-scale mixing of basinal brines with meteoric water. The cationic composition of these fluids indicates extensive interaction with crystalline rocks. Chlorite thermometry yielded temperatures of 260°C to 310°C. During this substage, uranium was probably leached from the Moldanubian crystalline rocks. The hydrothermal alteration of the ore substage followed, or partly overlapped in time, the pre-ore substage alteration. K–Ar ages of illite from ore substage alteration range from 277.2 ± 5.5 to 264.0 ± 4.3 Ma and roughly correspond with the results of chemical U–Pb dating of authigenic monazite (268 ± 50 Ma). The uranium ore deposition was accompanied by large-scale decomposition of biotite and pre-ore chlorite to Fe-rich illite and iron hydrooxides. Therefore, it is proposed that the deposition of uranium ore was mostly in response to the reduction of the ore-bearing fluid by interaction with ferrous iron-bearing silicates (biotite and pre-ore chlorite). The Th data on primary, mostly aqueous, inclusions trapped in carbonates of the ore substage range between 152°C and 174°C and total salinity ranges over a relatively wide interval of 3.1 to 23.1 wt% NaCl eq. Gradual reduction of the fluid system during the post-ore substage is manifested by the appearance of a new generation of authigenic chlorite and pyrite. Chlorite thermometry yielded temperatures of 150°C to 170°C. Solid bitumens that post-date uranium mineralization indicate radiolytic polymerization of gaseous and liquid hydrocarbons and their derivatives. The origin of the organic compounds can be related to the diagenetic and catagenetic transformation of organic matter in Upper Stephanian and Permian sediments. (3) K–Ar ages on illite from post-uranium quartz-carbonate-sulfide mineralization range from 233.7 ± 4.7 to 227.5 ± 4.6 Ma and are consistent with the early Tethys-Central Atlantic rifting and tectonic reactivation of the Variscan structures of the Bohemian Massif. A minor part of the late Variscan uranium mineralization was remobilized during this hydrothermal event.
Differences in Visual Programming for GIS
ArcGIS and AutoCAD Map 3D are both geographic information system (GIS) software. Both are used worldwide in many countries and companies. The dataflow design in visual editors is suitable for daily work. Visual languages are valuable for wide user community. Dataflow design automatizes typical GIS tasks and makes the processes universal. It is possible to construct simple or complex workflows with a visual editor in both software. The concept of visual programming is highly acceptable for GIS users because they think spatially and graphically. The article presented practical example for automatic finding of suitable area for construction of new hotel. Two data flow diagrams for the same task demonstrate the differences between graphical notations in ArcGIS and AutoCAD Map.
Epithermal gold mineralization in Costa Rica, Cordillera de Tilarán - exploration geochemistry and genesis of gold deposits
Epithermal gold mineralization in quartz veins forms part of a large ore belt extending in the NW-SE direction parallel to the Cordillera de Tilarán, Costa Rica. It is confined to Miocene-Pliocene andesites and basalts of the Aguacate Group volcanic arc. Gold-bearing quartz veins are related to faults and fractures of steep inclinations, accompanied by pronounced hydrothermal alteration. The key tectonic zones strike NW-SE but the majority of the ore veins are controlled by local extensional structures of Riedel shear type in the NE-SW, N-S to NNW-SSE directions. The brecciation, mylonitization and healing of deformed structures suggest that three main pulses of mineralization took place during the hydrothermal process. The gold is present as electrum (30 and 42 wt. % Ag) tiny inclusions up to 25 µm in size enclosed in quartz, pyrite and arsenopyrite. The other ore minerals are chalcopyrite, galena, sphalerite and marcasite and less abundant to scarce acanthite, pyrargyrite, greenockite, covellite, bornite and cassiterite. The principal elements exhibiting significant positive correlations with Au are Ag, Sb, As, Pb and Hg. Fluid inclusions of the H2O type were found in quartz and sphalerite from several Au-bearing occurrences. Temperatures of homogenization of fluid inclusions from several quartz generations and sphalerite vary generally between 150 and 290°C; the salinity of the aqueous solution was very low, not exceeding 5 wt. % NaCl equiv. The age of the mineralization is estimated in the period between the intrusion of the Guacimal Pluton and effusions of the discordant volcanic Monteverde Formation, which is barren (i.e. between c. 6.0 and 2.1 Ma). Geochemical study indicated altogether 14 promising gold-bearing areas in the Montes del Aguacate and Cordillera de Tilarán, of which four can be recommended for further exploration. [PUBLICATION ABSTRACT]