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Tytuł:
Calderón couples of rearrangement invariant spaces
Autorzy:
Kalton, N. J.
Powiązania:
https://bibliotekanauki.pl/articles/1292559.pdf
Data publikacji:
1993
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Opis:
We examine conditions under which a pair of rearrangement invariant function spaces on [0,1] or [0,∞) form a Calderón couple. A very general criterion is developed to determine whether such a pair is a Calderón couple, with numerous applications. We give, for example, a complete classification of those spaces X which form a Calderón couple with $L_∞.$ We specialize our results to Orlicz spaces and are able to give necessary and sufficient conditions on an Orlicz function F so that the pair $(L_F,L_∞)$ forms a Calderón pair.
Źródło:
Studia Mathematica; 1993, 106, 3; 233-277
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A note on galbed spaces
Autorzy:
Kalton, N. J.
Powiązania:
https://bibliotekanauki.pl/articles/744871.pdf
Data publikacji:
1980
Wydawca:
Polskie Towarzystwo Matematyczne
Opis:
The article contains no abstract
Źródło:
Commentationes Mathematicae; 1980, 21, 1
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Maintenance Operations: Workstation Adjustment, Working Posture, and Workers’ Perceptions
Autorzy:
Delleman, N. J.
Powiązania:
https://bibliotekanauki.pl/articles/90793.pdf
Data publikacji:
2000
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
ergonomics
pneumatic
oxy-gas
cutting
grinding
guidelines
ergonomia
cięcie
szlifowanie
wytyczne
Opis:
In the study maintenance workers were involved in pneumatic wrenching, oxy-gas cutting, and grinding at 5 different heights. Working posture and workers’ perceptions were measured. Guidelines on working height were formulated in order to minimize the load on the musculoskeletal system. Data from the present experiment as well as from literature were studied in depthin order to disclose generic mechanisms behind the adoption of working postures during visual-manual operations in relation to workstation adjustment. It was found, for instance, that the working posture was constrained by a strictly followed relationship between gaze inclination and head inclination for-/backwards. Also, the study provided insight into the role of visual interference, viewing distance, manipulation distance, hand grip of the tool, and body support for stability. Concerning evaluation criteria for working postures, it was concluded that neck flexion/extension (i.e., head inclination for-/backwards versus trunk inclination for-/backwards) seems to be the dominant determinant of neck load, as compared to head inclination for-/backwards. Furthermore, the position of the upper arm with respect to the trunk, that is, shoulder flexion/retroflexion in particular, seemed to be a dominant determinant of shoulder and shoulder girdle load, as compared to upper arm elevation.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2000, 6, 1; 3-46
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computational Modelling of a Tangentially Fired Boiler With Deposit Formation Phenomena
Autorzy:
Modliński, N.J.
Powiązania:
https://bibliotekanauki.pl/articles/185644.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pył węglowy
CFD
kocioł pyłowy
tangentially fired furnace
deposit formation
pulverised coal
Opis:
Any complete CFD model of pulverised coal-fired boiler needs to consider ash deposition phenomena. Wall boundary conditions (temperature and emissivity) should be temporally corrected to account for the effects of deposit growth on the combustion conditions. At present voluminous publications concerning ash related problems are available. The current paper presents development of an engineering tool integrating deposit formation models with the CFD code. It was then applied to two tangentially-fired boilers. The developed numerical tool was validated by comparing it with boiler evaporator power variation based on the on-line diagnostic system with the results from the full CFD simulation.
Źródło:
Chemical and Process Engineering; 2014, 35, 3; 361-368
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On operators on $L_0$
Autorzy:
Kalton, N. J.
Powiązania:
https://bibliotekanauki.pl/articles/725200.pdf
Data publikacji:
1984
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Źródło:
Colloquium Mathematicum; 1984, 48, 1; 81-88
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early Cambrian 'soft-shelled' brachiopods as possible stem-group phoronids
Autorzy:
Balthasar, U
Butterfield, N.J.
Powiązania:
https://bibliotekanauki.pl/articles/21500.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
paleontology
Early Cambrian
brachiopod
soft-shelled brachiopod
phoronid
Brachiopoda
Phoronida
Lophophorata
Lophotrochozoa
Lingulosacculus nuda
Mural Formation
preservation
Opis:
Brachiopods and phoronids are widely recognised as closely related lophophorate phyla, but the lack of morphological intermediates linking the bivalved bodyplan of brachiopods with tubular phoronids has frustrated precise phylogenetic placement. Here we describe Lingulosacculus nuda gen. et sp. nov., a new “soft−shelled” brachiopod from the Early Cambrian Mural Formation of western Alberta which provides a plausible candidate for a phoronid stem−group within (paraphyletic) Brachiopoda. In addition to its non−biomineralised shell, L. nuda had a ventral valve with an exceptionally long, pocket−like extension (pseudointerarea) that would have allowed the transformation of criss−crossing brachiopod−type musculature to the longitudinal arrangement typical of phoronids. “Soft−shelled” linguliform brachiopods have previously been reported from both the Chengjiang and Burgess Shale Lagerstätten which, together with L. nuda, probably represent two independent losses of shell mineralisation in brachiopods.
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 2; 307-314
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A note on the independent Roman domination in unicyclic graphs
Autorzy:
Chellali, M.
Rad, N. J.
Powiązania:
https://bibliotekanauki.pl/articles/255989.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Roman domination
independent Roman domination
strong equality
Opis:
A Roman dominating function (RDF) on a graph G= (V, E) is a function ƒ : V → {0, 1, 2} satisfying the condition that every vertex u for which ƒ(u) = 0 is adjacent to at least one vertex v for which ƒ(v)=2. The weight of an RDF is the value [formula]. An RDF ƒ in a graph G is independent if no two vertices assigned positive values are adjacent. The Roman domination number ΥR (G) (respectively, the independent Roman domination number ΥR(G) is the minimum weight of an RDF (respectively, independent RDF) on G. We say that ΥR(G) strongly equals iR(G), denoted by ΥR(G) ≡ iR(G), if every RDF on G of minimum weight is independent. In this note we characterize all unicyclic graphs G with ΥR(G) ≡ iR(G).
Źródło:
Opuscula Mathematica; 2012, 32, 4; 715-718
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of Sound Attributes of Multichannel and Mixed-Down Stereo Recordings
Autorzy:
Kin, N. J.
Plaskota, P.
Powiązania:
https://bibliotekanauki.pl/articles/177408.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound quality
recording formats
art of mixing
Opis:
The work presents a comparison of some sound attributes perceived at a multichannel and stereo playback of musical recordings. The width of the virtual source, coherence impression, total size of sound scene, general quality and balance were the subjects of interest after the format reduction in accordance with the ITU recommendation. The results showed that evaluation of these attributes depends on the way the original audiosphere has been created in the surround system, for example, for a narrow virtual source the mix-down process causes only a small change in its size but for a broad source the observed degradation is significant. In addition, different ways of conversion from the multichannel to stereo format have been tested for compatibility.
Źródło:
Archives of Acoustics; 2011, 36, 2; 333-345
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and Optical Properties of Fe2O3 - NiO mixed Thin Films Prepared by Chemical Spray Pyrolysis
Autorzy:
Mohmmed, N. J.
Habubi, M. N.
Powiązania:
https://bibliotekanauki.pl/articles/412381.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Fe2O3
spray pyrolysis technique
structural properties
optical properties
Opis:
Mixed Fe2O3 - NiO thin films have been prepared by chemical Spray pyrolysis technique onto glass substrate preheated to 450 °C. The thickness of thin films was found to be (400 ±20) nm. XRD measurements reveal that all the film exhibit polycrystalline hexagonal wrutzite with a preferred orientation along (104) plane for pure and 10 % and 20 % Ni, while for the rest the structure was amorphous. AFM analysis indicate a nanostructure for all the films. The optical energy gap was found to be increased from optical transitions seems to be direct and the optical energy gap seems to be increased from 2.5 to 2.69 eV as the percentage of NiO increase.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 14, 1; 65-85
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sedimentological and palaeoecological significance of the trace fossils of the Jurassic rocks of the Jhura Dome, Mainland Kachchh, western India
Autorzy:
Patel, S. J.
Patel, N. J.
Powiązania:
https://bibliotekanauki.pl/articles/2077327.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Jurassic
ichnoassemblages
ichnoguilds
ichnofacies
depositional environment
Kachchh
India
jura
skamieniałość śladowa
Indie
Opis:
The Middle to Late Jurassic succession of the Jhura Dome (Jhurio and Jumara formations) of the Mainland Kachchh, western India, comprises a ~500 m thick succession of clastic carbonates and mixed siliciclastic-carbonates, intercalated with shales. The sequence, as based on sedimentological characteristics, exhibits six sedimentary facies and four subfacies. Certain exceptional bands of the ripplemarked calcareous sandstone, shale and oolitic limestone facies are rich in ammonites, belemnites, brachiopods and bivalves. Thirty four ichnogenera were also identified and analysed paleoecologically. These trace fossils represent five ethological categories and six ichnoassemblages. Seventeen ichnoguilds are demonstrated based on space utilization for characterising the ecological complexity of ichnoassemblages. Bathymetric control of the trace fossils resulted with development of Skolithos, Cruziana and Zoophycos ichnofacies type conditions. The sedimentological and ichnological data analysis revealed seven distinctive depositional regimes ranging from offshore shelf below storm wave base to middle shoreface.
Źródło:
Volumina Jurassica; 2015, 13, 2; 101--139
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertebrate paleoecology of the late Campanian (Cretaceous) Fruitland Formation, San Juan Basin, New Mexico (USA)
Autorzy:
Spencer, G.L.
Mateer, N.J.
Powiązania:
https://bibliotekanauki.pl/articles/23423.pdf
Data publikacji:
1983
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Sediments of the Fruitland Formation in northwestern New Mexico represent a delta plain that prograded northeastward over the retrating strandline of the North American epeiric seaway during the late Campanian. Fruitland fossil vertebrates are fishes, amphibians, lizards, a snake, turtles, crocodilians, dinosaurs (mostly hadrosaurs and ceratopsians) and mammals. Autochthonous fossils in the Fruitland Formation represent organisms of the trophically-complex Parasaurolophus community. Differences in diversity, physical stress and life-history strategies within the Parasaurolophus community fit well the stability-time hypothesis. Thus, dinosaurs experienced relatively low physical stress whereas fishes, amphibians, small reptiles and mammals experienced greater physical stress. Because of this, dinosaurs were less likely to recover from an environmental catastrophe than were smaller contemporaneous vertebrates. The terminal Cretaceous extinctions selectively eliminated animals that lived in less physically-stressed situations, indicating that the extinctions resulted from an environmental catastrophe.
Źródło:
Acta Palaeontologica Polonica; 1983, 28, 1-2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strong geodomination in graphs
Autorzy:
Rad, N. J.
Mojdeh, D. A.
Powiązania:
https://bibliotekanauki.pl/articles/255061.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
geodomination
k-geodomination
open geodomination
Opis:
A pair x, y of vertices in a nontrivial connected graph G is said to geodominate a vertex v of G if either v ∈ {x, y} or v lies in an x - y geodesic of G. A set S of vertices of G is a geodominating set if every vertex of G is geodominated by some pair of vertices of S. In this paper we study strong geodomination in a graph G.
Źródło:
Opuscula Mathematica; 2008, 28, 3; 279-285
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
k-Perfect geodominating sets in graphs
Autorzy:
Mojdeh, D. A.
Rad, N. J.
Powiązania:
https://bibliotekanauki.pl/articles/255558.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
geodominating set
perfect geodomination number
pendant vertex
pendant edge
Opis:
A perfect geodominating set in a graph G is a geodominating set S such that any vertex v ∈ V(G)\S is geodominated by exactly one pair of vertices of S. A k-perfect geodominating set is a geodominating set S such that any vertex v ∈ V(G)\S is geodominated by exactly one pair x, y of vertices of S with d(x, y) = k. We study perfect and k-perfect geodomination numbers of a graph G.
Źródło:
Opuscula Mathematica; 2007, 27, 1; 51-57
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical approximation of self-consistent Vlasov models for low-frequency electromagnetic phenomena
Autorzy:
Besse, N.
Mauser, N. J.
Sonnendrücker, E.
Powiązania:
https://bibliotekanauki.pl/articles/929699.pdf
Data publikacji:
2007
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
model Vlasova-Darwina
model Vlasova-Poiswell'a
metoda Lagrangiana
niskoczęstotliwościowe zjawisko elektromagnetyczne
Vlasov-Darwin model
Vlasov-Poisswell model
semi-Lagrangian method
low-frequency electromagnetic
Opis:
We present a new numerical method to solve the Vlasov-Darwin and Vlasov-Poisswell systems which are approximations of the Vlasov-Maxwell equation in the asymptotic limit of the infinite speed of light. These systems model low-frequency electromagnetic phenomena in plasmas, and thus “light waves” are somewhat supressed, which in turn allows the numerical discretization to dispense with the Courant-Friedrichs-Lewy condition on the time step. We construct a numerical scheme based on semi-Lagrangian methods and time splitting techniques. We develop a four-dimensional phase space algorithm for the distribution function while the electromagnetic field is solved on a two-dimensional Cartesian grid. Finally, we present two nontrivial test cases: (a) the wave Landau damping and (b) the electromagnetic beam-plasma instability. For these cases our numerical scheme works very well and is in agreement with analytic kinetic theory.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2007, 17, 3; 361-374
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, structure and performance of calcium silicate ion exchangers from recycled container glass
Autorzy:
Coleman, N. J.
Li, Q.
Raza, A.
Powiązania:
https://bibliotekanauki.pl/articles/109960.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
tobermorite
sorbent
hydrothermal synthesis
cullet
recycling
ion exchange
Opis:
Numerous technical, economic and societal factors limit the recycling of waste soda-lime-silica glass back into the primary production process and accordingly alternative applications for this material are sought. This study demonstrates that waste soda-lime-silica container glass is a suitable feedstock material for the production of tobermorite, a calcium silicate cation exchanger. Tobermorites were synthesised at 100 °C from stoichiometric mixtures of container glass and lime under alkaline hydrothermal conditions. Increasing concentrations of sodium hydroxide (between 1.0 M and 4.0 M) in the reaction mixture promoted the formation and crystallisation of tobermorite, and also resulted in greater fragmentation of the silicate chains along the b-axis direction. The maximum removal capacities of these tobermorite specimens for Cd2+ (441 mg g-1) and Zn2+ (122 mg g-1) compared well with those of other waste-derived sorbents. Superior Cd2+- and Zn2+-uptake capacities and kinetics were observed for the least crystalline tobermorite specimen, indicating that stacking defects facilitate the transport and exchange of cations within the lattice.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 5-16
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical properties improvement of the diesel engine lubricant oil reinforced nanomaterials
Autorzy:
Hadi, N. J.
Al-Hussain, R. K. A.
Powiązania:
https://bibliotekanauki.pl/articles/95364.pdf
Data publikacji:
2018
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
lubricant oil
nanofluids
viscosity
thermal conductivity
thermal images
tribology
oleje smarowe
nanopłyny
lepkość
przewodność cieplna
termogram
tribologia
Opis:
This research focuses on the effect of nanomaterials on the physical properties of a local Iraqi lubricant oil (20W-50), which is widely used in diesel engines. The concentrations of 0.001, 0.2 and 0.5 wt% of Al2O3 NPs and CNT are dispersed in the oil with the help of a suitable surfactant using a magnetic stirrer and a sonication process. The density, surface tension, dynamic viscosity, kinematic viscosity, flash point, fire point, pour point, thermal conductivity, thermal images, wear and the coefficient of friction of the oil with and without nanomaterials are tested. The results were shown that the higher concentrations of NPs, the better properties for the engine oil. The density for Al2O3 nanooil indicates a small change at 0.001 and 0.2 wt%, and a decrease at 0.5 wt% ratio. Also, the density of CNT oil shows a slight change at 0.001and then decreasing at 0.2 and 0.5 ratios. In addition, the surface tension of both nanooils are increased. The dynamic viscosity slightly change with an addition of the NPs especially at 20°C and 30°C. Also, there is a convergence in the viscosity values between base and nanooils at 40°C and 50°C. Also, the dynamic viscosity indicates shear thickening behavior at low shear rate, while in the high shear rate the viscosity attempts to be more stable. The kinematic viscosity increases with an increased concentration of the NPs at 40°C and 100°C for both nanooils. The flash and fire point are increasing for both nanooils and Al2O3 nanooil indicates a lower pour point than that of CNT oil. CNT oil indicates higher dissipating heat friction and thermal conductivity than that of Al2O3 nanooil. Thermal images are supported by thermal conductivity and flash point behavior, while the tribology tests are compatible with viscosity behavior. A significant reduction in the coefficient of friction and wear loss is produced for both nanooils.
Źródło:
Journal of Mechanical and Energy Engineering; 2018, 2, 3; 233-244
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrothermal synthesis of lithium silicate from waste glass. A preliminary study
Autorzy:
Coleman, N. J.
Hurt, A. P.
Raza, A.
Powiązania:
https://bibliotekanauki.pl/articles/110613.pdf
Data publikacji:
2015
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
hydrothermal synthesis
glass
cullet
recycling
lithium metasilicate
zinc
Opis:
Current environmental directives to conserve resources and to divert waste streams have generated significant interest in mineral recycling. In this respect, this preliminary study has demonstrated that lithium metasilicate can be prepared by hydrothermal reaction between waste container glass and lithium hydroxide solutions at 100 °C. Minor proportions of calcium hydroxide, calcite, lithium carbonate and tobermorite were also produced during the reaction. Percentage crystallinity and proportion of lithium metasilicate in the reaction product were found to increase as functions of lithium hydroxide concentration (between 1 and 4 M). This research has also shown that the lithium metasilicate phase can take up 6.4 mmol/g of Zn2+ ions after 24 h during batch sorption. Further work to optimise the yield and to appraise the antimicrobial properties of Zn2+-bearing lithium metasilicate is now warranted.
Źródło:
Physicochemical Problems of Mineral Processing; 2015, 51, 2; 685-694
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Linear matrix inequalities control driven for non-ideal power source energy harvesting
Autorzy:
Ferreira, D. C.
Chavarette, F. R.
Peruzzi, N. J.
Powiązania:
https://bibliotekanauki.pl/articles/281518.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
energy harvesting
efficiency
control
non-ideal excitation
Opis:
The dynamic model of a linear energy harvester excited by a non-ideal power source is coupled to a controller to maximum vibration adjustment. Numerical analysis is taken to evaluate the energy harvested keeping the vibration optimized for the maximum interaction to the energy source using linear matrix inequalities for control driven. The dimensionless power output, actuation power and net output power is determined. As a result, it is possible to verify that the total energy harvested via exogenous vibration using the proposed controller is increased up to 65 times when in comparison to the open loop system.
Źródło:
Journal of Theoretical and Applied Mechanics; 2015, 53, 3; 605-616
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new genus of eomyid rodent from the Miocene of Nevada
Autorzy:
Smith, K S
Cifelli, R.L.
Czaplewski, N.J.
Powiązania:
https://bibliotekanauki.pl/articles/21894.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Megapeomys
Miocene
eomyid rodent
Apeomys
Rodentia
Nevada
Eomyidae
new genus
rodent
paleontology
Apeomyoides
Opis:
The description of a new genus (Apeomyoides) of eomyid rodent from the Miocene of Nevada increases the diversity of known taxa, enhances the geographic range, and extends the biochronology for the Apeomyinae (Eomyidae). Three groups of Eomyidae are known from the fossil record of North America. Of the three groups, Neogene taxa include four genera representing the Eomyinae and two genera representing the Apeomyinae; no genera of the subfamily Yoderimyinae are known from the Neogene of the continent. This diversity represents a significant reduction of eomyid taxa compared to the Paleogene, from which 17 genera of eomyines and three genera of yoderimyines are known. In Eurasia, 11 genera of eomyids occurred during the Neogene, with a few taxa that persisted until about 2 million years before present. At present, there are no known eomyids from the last 4.5 million years of the Neogene in North America. Apeomyoides savagei is referable to the subfamily Apeomyinae based on several key structures of the teeth and mandible. This new eomyid is part of the Eastgate local fauna, collected from volcanic ash deposits of the Monarch Mill Formation, Churchill County, Nevada. Apeomyoides has an occlusal pattern that shares characteristics of apeomyines from both North America (Megapeomys and Arikareeomys) and Eurasia (Apeomys and Megapeomys). The unique occlusal pattern and large size of Apeomyoides demonstrates that not all eomyids from North America were small or that their lineages decreased in size through time. Apeomyoides also may provide evidence, which challenges the hypothesis that eomyids within a single lineage from North America became more lophodont in geologically younger genera.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł

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