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The first unequivocal actinoceratid cephalopod from the late Katian (Late Ordovician) shales of the Prague Basin (Central Bohemia), Adamsoceras? hanusi sp. nov., is described. The only specimen contains several fragmented but undeformed siphuncular segments. The shell wall, septa, ectosiphuncle and annulosiphonate deposits are dissolved but their original shape is reflected by cavities left after them inside the specimen. The endosiphuncular canal system inside the siphuncle is preserved, including the central canal, radial canals and perispatium. The shape of the empty spaces and structures inside the siphuncle indicate that the growth of the annulosiphonate deposits was irregular and uneven; the deposits pushed back the original soft tissue inside the siphuncle and the present irregular structure of the endosiphuncular system was thus formed. The preservation of the central and radial canals additionally shows that the walls of the individual blood vessels running through the canals must have been soft, elastic, and probably had a higher preservation potential than the rest of the soft tissue. Consequently, the shape of the endosiphuncular system is different in each median section and each segment, and assignment to a particular system type is thus not possible. We conclude that definition of taxa based on previously established types of endosiphuncular systems might be artificial in at least some actinoceratids. [ABSTRACT FROM AUTHOR]

The vast majority of cephalopods of the order Tarphyceratida are known from regions that were located at mid- or low palaeolatitudes during the Ordovician (mainly Baltica, Laurentia, and Chinese palaeoblocks). Only a handful of tarphyceratid specimens are known from high palaeolatitude regions of peri-Gondwana and Gondwana. Here, we describe the two best-preserved trocholitid cephalopods known to date from the Ordovician of the Prague Basin. The first is from the late Darriwilian/early Sandbian Dobrotivá Formation and is assigned to Trocholites fugax, a species previously recorded from roughly coeval strata of Iberia, France, and Bohemia. The specimen thus strengthens previous hypotheses regarding the interchange of non-benthic faunas between Baltica and different regions of peri-Gondwana during the Middle/ Late Ordovician boundary interval. The second specimen, assigned to a new species of Trocholites chaloupkai sp. nov., is from the late Sandbian–early Katian Zahořany Formation and thus represents one of the stratigraphically youngest Trocholites in the Ordovician of peri-Gondwana. Internal structures of the shell of the holotype of the new species were studied using micro-CT tomography. This revealed that T. chaloupkai sp. nov. closely resembles the stratigraphically older (Darriwilian) species Trocholites depressus from Estonia. [ABSTRACT FROM AUTHOR]

Recent research on waste management has primarily focused on the circular economy. This concept leads to increased sustainability by putting emphasis mainly on the reduction of waste production, recycling, and restriction of landfilling. It has already been incorporated in many national directives and legislations, while its effective implementation can be aided by mathematical programming. For the optimal operation of Waste-to- Energy plants, it is necessary to take into consideration the varying compositions and lower heating values (LHV) of the utilized wastes (or other commodities suitable for energy recovery). Because the LHV significantly influences the plant operating mode, waste heterogeneity can result in serious operating problems if bad strategic decisions had been made. The approach discussed represents a mixing task which considers the heterogeneity of wastes originating from different sources, the corresponding LHVs, and their impact on the final energy recovery. The implementation includes plant locations and network flows, operating costs (together with the return on investment), waste transport, and corrections of LHVs because all these factors are closely linked to the resulting profits from energy sales. The constraints consist of the necessary balances, such as capacities or heating limits. The developed optimization model is verified using a small waste transport network. The result of the model is a proposal for the redistribution of the mixed municipal waste, bulky waste and other combustible waste into specific technology sinks (Waste-to-Energy plant, landfill, cement plant). This article focuses on energy recovery from waste, which is also a crucial part of the transition to the circular economy. Future research is also outlined concerning the extension of the model's environmental component and the large size of typical, real world optimization tasks of the respective type. [ABSTRACT FROM AUTHOR]

This study describes 18 specimens representing the earliest growth parts of orthoceratoid cephalopods, most of which have been recently obtained from the Middle Ordovician strata of the Prague Basin, central Bohemia. Only about 20 specimens of Ordovician orthoceratoids displaying embryonic shell are known globally and the Bohemian material thus significantly expands their current record. The studied collection includes twelve specimens assigned to the species Bactroceras sandbergeri and shows that the morphological variability in early ontogenetic growth stages of this species was rather low. The absence of a cicatrix was definitely confirmed in this phylogenetically important cephalopod. Six other specimens investigated herein are indeterminate orthoceratids. Initial chambers, where preserved, are generally large compared to known, stratigraphically younger specimens. This is interpreted here as supporting the previously postulated trend of decreasing the egg- and hatchling sizes in orthoceratoid cephalopods from mid-Ordovician times onwards. Alternatively, the large sizes of these Bohemian orthoceratids may be explained by the position of the Prague Basin in relatively cool-water high palaeolatitudes during the Middle Ordovician. [ABSTRACT FROM AUTHOR]

The colour pattern is a conspicuous character of nautiloid shells. Better understanding to its evolution and possible function is limited by the rarity of preservation. The majority of colour patterns are preserved in demersal late Silurian breviconic oncocerids, while in other cephalopod orders and shell forms, it is limited or unknown. The colour pattern of late Silurian oncocerids (Oonoceratidae Flower, 1942 and Oocerinidae Teichert, 1939) possessing cyrtoconic and slightly curved shells is documented in nine species from Bohemia belonging to five genera. The cyrtocones Richardsonoceras Foerste, 1933 and Oonoceras Hyatt, 1884 exhibit slightly irregular oblique zig-zag patterns, which may be disrupted and may pass into irregular patches of dark pigment. By contrast, the colour pattern in Oocerina Foerste, 1926, possessing similar shell shape to Oonoceras, consists of narrow, transversal, slightly undulated bands. The short and very slightly curved shell of Chromatoceras gen. nov. displays bilaterally asymmetrical irregular bands or, as in the type species, irregular, asymmetrical, strongly discontinuous colouration. Distinct changes of patterning throughout ontogeny are documented herein in oncocerids, including narrowing of bands, irregular juvenile colouration passing into zig-zag bands and ventrally disappearing colouration in adult shell. Bilaterally asymmetric and irregular pattern, for the first time documented in nautiloids, appeared in probably more demersal cephalopods. The asymmetrical pattern exhibits high intraspecific variation unknown in other nautiloids. All studied oncocerids likely inhabited euphotic zone and the primary function of the colour patterns is camouflage. [ABSTRACT FROM AUTHOR]

In engineering practice, it is common that heat transfer equipment containing tube bundles are designed under the assumption of uniform flow distribution. Such a flawed approach may easily lead to various operating problems (increased local fouling rates, mechanical failures, etc.) and significantly shortened service life. Accordingly, knowing the flow pattern in the bundle is crucial to proper design of the respective apparatuses. Although computational fluid dynamics (CFD) models yield very accurate data, due to their inherent computational cost they are not really suitable for evaluation of large sets of possible flow system geometries. Algebraic or otherwise greatly simplified models, on the other hand, are acceptable in terms of computational performance, but generally suffer from low accuracy and limited applicability to more complex meshes. This paper therefore proposes a computationally efficient flow distribution model whose principle is analogous to nonlinear finite element analysis (FEA). Unlike in many other simplified models, no special correction algorithms or user modifications are needed here because the underlying system of equations is solved in the matrix form and the corrector step is mesh-independent. Additionally, results provided by the model are compared to the data obtained using detailed CFD analyses of several different flow systems. Although the accuracy of the model does not match that of CFD, it can still be used at the beginning of a design process to discard the obviously unsuitable options, which would otherwise have to be evaluated via lengthy CFD simulations. [ABSTRACT FROM AUTHOR]

Cephalopods of the order Lituitida Starobogatov, 1983 are a common component of low-latitude, warm-water fossil assemblages of the Middle and Upper Ordovician strata of Baltica and the Chinese paleocontinents (North and South China, Tarim, Tibet). The lituitids are also known from Laurentia, Siberia and mid-latitude Avalonia and Argentine Precordillera. By contrast, in the high-latitude regions of peri-Gondwana, the group is known only from a Trilacinoceras Sweet, 1958 from the late Darriwilian rocks of the Iberian peninsula and Rhynchorthoceras cf. angelini (Boll, 1857) from the upper part of the Klabava Formation (uppermost Dapingian Stage) of Bohemia. The single specimen of the latter species is the earliest known lituitid known from European and African peri-Gondwanan basins. The timing of its appearance coincides with a time interval of an increased faunal interchange between Perunica and Baltica during the late Dapingian time. Six specimens of two lituitids, Lituites lituus de Montfort, 1808 and Trilacinoceras cf. discors (Holm, 1891), are for the first time reported from the late Darriwilian Dobrotivá Formation. Finds of these lituitids are coeval with an occasional dispersion event of another typically low-latitude cephalopod group, the Tarphyceratida, to high latitudes. [ABSTRACT FROM AUTHOR]

The Ordovician to Carboniferous cephalopods of the order Actinoceratida (Teichert, 1933) are distinguished from all other cephalopods by their large siphuncles, which typically contain heavy, calcareous deposits enclosing a complex system of canals. These peculiar structures were already recognised in the 19th century, but it was only in the 20th century that they were properly described and interpreted in a more systematic manner with respect to the phylogeny and palaeoecology of the group. In the present study, we investigate a uniquely preserved actinoceratid cephalopod from the late Katian part of the Králův Dvůr Formation (Prague Basin, Central Bohemia), in order to address the magnificent works of C. Teichert, R. H. Flower, M. Wade and H. Mutvei. The specimen, tentatively assigned to the ormoceratidan genus Adamsoceras, consists of four isolated fragments of the siphuncle (nine siphuncular segments) and small remains of phragmocone chambers. All original calcareous parts of the conch were dissolved during diagenesis and fossilisation processes, while the spaces left by decayed soft tissues were filled with pyrite (secondarily converted into limonite). In other words, the specimen is a cast of the axial canal, radial canals and perispatium, plus some remains of phragmocone chambers. Cavities inside the cast mirror the shape of dissolved endosiphuncular deposits and ectosiphuncle; nothing is preserved of the outer shell wall and septa. The remains of phrag­mocone chambers are diagenetically flattened, but the siphuncle is undeformed, supposedly because it was protected against compaction by the extensive endosiphuncular deposits and possibly by the filling of the endosiphuncular canals with pyrite. The preservation of the specimen enabled the application of the micro-CT scanning. This non-destructive method has proved invaluable for studying fossils that cannot be otherwise studied using standard oriented sectioning. It also enabled the construction of a virtual model of the specimen, which facilitated the investigation of the siphuncular structure in 3D. Preliminary results show that the endosiphuncular deposits grew unevenly, resulting in highly irregular shapes and distribution of the radial canals, and an irregularly flattened form of the central canal. The flattening of the central canal is interpreted as reflecting the dorso-ventral plane of sym­metry of the siphuncle. Furthermore, the endosiphuncular structures did not form symmetrically and their appearance depends on the selected median section. This suggests that the distinction between several types of endosiphuncular systems sensu Teichert and Flower and the taxonomy derived from these distinctions might be, at least in some actinoceratids, artificial, resulting from studying specimens in 2D median sections. The studied specimen represents the only unequivocal actinoceratid from the Ordovician of the high-palaeolatitude Prague Basin. Since actinoceratid cephalopods were abundant during the Ordovician mainly in low-palaeolatitude carbonate environments, the presence of this specimen in the Prague Basin supports previous indications of a faunal connection between the high and low palaeolatitudes during the late Katian age. [ABSTRACT FROM AUTHOR]

Sphooceras truncatum (Barrande, 1860), a Silurian straight-shelled cephalopod with a short finger-shaped shell, is one of a few cephalopods in which natural truncation of the apical part of the phragmocone from the rest of the conch is confirmed. Periodic natural removal of the apical part of the shell (4 to 5 phragmocone chambers) preceded formation of a terminal callus and a calcareous plug closing the septal foramen. The apical callus probably originated by fusion of the truncation septum with episeptal deposits. These structures temporarily formed the new apex on which two additional calcareous layers had been secreted. A unique specimen preserves a colour pattern in the convex apical region, which proves that the shell in Sphooceraswas temporarily completely surrounded bymantle extending fromthe body chamber, i.e. the cephalopod was at least temporarily endocochleate. The co-occurrence of different growth stages of S. truncatum together with one type of short juvenile orthoceracone shell, with a maximum of eight phragmocone chambers and a very small subglobular initial chamber indicates that these embryonic shells may belong to Sphooceras. Two other genera are discussed, both previously included in the family Sphooceratidae: Disjunctoceras Gnoli in Kiselev, 1992 and Andigenoceras Gnoli in Kiselev, 1992. The newly discovered thickening of the apex in "Disjunctoceras" disjunctum, the type species of Disjunctoceras, indicates that this species does not differ substantially from Sphooceras and should be reassigned to this genus. Similarly, representatives of Andigenoceras also possess characteristic features of Sphooceras. Sphooceras has many features characteristic for modern cephalopods: short, thin-walled, semi-internal shell; phragmocone reduced to only a few chambers; uncalcified connecting rings; apical callus (a structure analogous to the belemnite rostrum); retractor muscle scars situated dorsally; very small protoconch without cicatrix. In some exceptionally well-preserved cephalopods with orthoceracone shell radula with seven rows of teeth were observed. All these features support the thesis that some straight-shelled cephalopods are evolutionarily closer to coleoids than nautiloids and their separation from nautiloids is legitimate. Vascular imprints on the surface of the cameral deposits provide further support for their primary origin and the existence of a cameral mantle. The character of cameral deposits in Sphooceras demonstrates that the systematic value of these structures in other straight-shelled cephalopods, a subject of controversy, has limited value. The morphology of Sphooceras also demonstrates that the boundary between endo-cochleate and ectocochleate cephalopods is not sharp, i.e. internalisation of the shell in cephalopods occurred repeatedly. [ABSTRACT FROM AUTHOR]

The article focuses on the life and works of Radvan Horny who is a Czech palaeontologist and natural scientist and born on June 29, 1932 in Prague, Czech Republic. Horny's works include the scientific paper published in 1950, the palaeontological paper in 1952, and other scientific and professional papers, addressing primarily Lower-Palaeozoic molluscs. Horny was a geologist with the Central Geological Survey in 1955. Moreover, Horny has one more project that he wants to finish regarding gastropods from tuffitic Silurian limestones of the Kopanina Formation at the site Resna.

A cephalopod Peismoceras Hyatt, 1884 from the Silurian (Gorstian) of Bohemia is the single known nautiloid genus of the suborder Barrandeocerina with a documented colour pattern. However, spiral bands on lateral side of the shell, oblique to the shell axis, illustrated by J. Barrande in 1865 in Peismoceras pulchrum and later mentioned in several papers are not typical for this species. Zigzag bands are more common and they are developed either on the entire circumference of the shell or on one lateral side, while the other side retained the above mentioned spiral bands. A marked asymmetry of colour pattern on lateral sides has been observed in several cases, but with no proven relationship to the slight dextral coiling of the shell. Densely spaced longitudinal bands preserved on ventral side of P. asperum (Barrande, 1865) are illustrated for the first time. Some unusual shell abnormalities occurring in Peismoceras are discussed. [ABSTRACT FROM AUTHOR]