350 research outputs found
Experimental taxonomy exposes ontogenetic variability and elucidates the taxonomic value of claw configuration in Milnesium Doyère, 1840 (Tardigrada : Eutardigrada : Apochela)
Experimental taxonomy exposes ontogenetic variability and elucidates the taxonomic value of claw configuration in Milnesium Doyère, 1840 (Tardigrada : Eutardigrada : Apochela)
In this paper we describe a new apochelan species, Milnesium variefidum sp. nov. from Scotland and provide novel morphological and molecular data for Milnesium berladnicorum Ciobanu et al., 2014. The new species differs from the most similar M. berladnicorum by the presence of developmental dimorphism in claw configuration, absent or weakly developed cuticular bars under claws I-III, a different arrangement of cuticular pseudoplates, and by differences in the sequences of three nuclear DNA fragments: 18S rRNA (p-distance: 0.6%), 28S rRNA (2.0%), ITS-2 (9.3%), and on mitochondrial gene COI (12.4%). Although ontogenetic claw configuration change was suspected to occur in some Milnesium species, we are the first to document it through the combined use of traditional, molecular and experimental methodologies. We discuss the implications of the observed phenomenon for the taxonomy of the genus and propose a new diagnostic key to all Milnesium species described up to the end of 2015. We also review other traits used for species differentiation in the genus and offer recommendations to improve the quality of future descriptions as well as suggest a need for integrative redescriptions of the known species. Finally, we propose to suppress M. dujiangensis and M. tardigradum trispinosum and suggest that M. alpigenum and M. quadrifidum are valid species that require thorough redescriptions
Dunhuang – geneza powstanie i strategiczne znaczenie miasta za czasów cesarza Wudi z dynastii Han
Dunhuang – the origins of foundation and the strategic importance of the city during the reign of Emperor Wu of the Han Dynasty): Dunhuang was arguably one of the most important cities on the so-called Silk Road. Its establishment was made possible due to Han emperor Wudi’s war against the nomadic tribes of the
Xiongnu, who posed a major threat to the Chinese during the early years of the Han dynasty. The city was established as a strategic military settlement that was part of the regional tuntian system, and its role was to help secure the western borders of the empire. Due to the discovery of potential trading partners in the west during the reign of emperor Wudi, as well as the war which resulted in the vassalization of city states in the Takla Makan desert, Dunhuang became a trading hub from where caravans from the Chinese interior travelled west, which only increased its strategic value. This article will discuss what caused the evolution of Dunhaung from a frontier tuntian settlement into a major trading hub and strategically important city
Deceptive conservatism of claws : distinct phyletic lineages concealed within Isohypsibioidea (Eutardigrada) revealed by molecular and morphological evidence
Isohypsibioidea are most likely the most basally branching evolutionary lineage of eutardigrades. Despite being second largest eutardigrade order, phylogenetic relationships and systematics within this group remain largely unresolved. Broad taxon sampling, especially within one of the most speciose tardigrade genera, Isohypsibius Thulin, 1928, and application of both comparative morphological methods (light contrast and scanning electron microscopy imaging of external morphology and buccal apparatuses) and phylogenetic framework (18S + 28S rRNA sequences) resulted in the most comprehensive study devoted to this order so far. Two new families are erected from the currently recognised family Isohypsibiidae: Doryphoribiidae fam. nov., comprising all aquatic isohypsibioids and some terrestrial isohypsibioid taxa equipped with the ventral lamina; and Halobiotidae fam. nov., secondarily marine eutardigrades with unique adaptations to sea environment. We also split Isohypsibius into four genera to accommodate phylogenetic, morphological and ecological variation within the genus: terrestrial Isohypsibius s.s. (Isohypsibiidae), with smooth or sculptured cuticle but without gibbosities; terrestrial Dianea gen. nov. (Isohypsibiidae), with small and pointy gibbosities; terrestrial Ursulinius gen. nov. (Isohypsibiidae), with large and rounded gibbosities; and aquatic Grevenius gen. nov. (Doryphoribiidae fam. nov.), typically with rough cuticle and claws with branches of very similar heigths. Claw morphology is reviewed and, for the first time, shown to encompass a number of morphotypes that correlate with clades recovered in the molecular analysis. The anatomy of pharynx and cuticle are also shown to be of high value in distinguishing supraspecific taxa in Isohypsibioidea. Taxonomy of all isohypsibioid families and genera is discussed, with special emphasis on the newly erected entities. Finally, a dychotomous diagnostic key to all currently recognised isohypsibioid families and genera is provided
Magnetic and intruder rotational bands in (113)In
©2005 American Physical SocietyExcited states in ¹¹³In were populated via the reactions ¹⁰⁰Mo(¹⁸O,p4n)¹¹³In and ¹¹⁰Pd(7Li,4n)¹¹³In. The two known ΔJ = 2 intruder bands, based on the πg7/2 ⊗ d5/2 and πh11/2 orbitals, have been extended by 8¯h to spins (49/2+)¯h and (55/2−)¯h, respectively. The previous finding of three sequences of ΔJ = 1 γ -ray transitions has been confirmed. A self-consistent cranked shell-model calculation gives a good description of the contrasting alignment patterns of the two ΔJ = 2 intruder bands. The intruder bands, the known sequences ofM1 transitions, and spherical levels together represent a coexistence of three different excitation modes in this nucleus.S. Naguleswaran, R. S. Chakrawarthy, U. Garg, K. L. Lamkin, G. Smith, J. C. Walpe, A. Galindo-Uribarri, V. P. Janzen, D. C. Radford, R. Kaczarowski, D. B. Fossan, D. R. Lafosse, P. Vaska, Ch. Droste, T. Morek, S. Pilotte, J. DeGraaf, T. Drake, and R. Wys
Evaluating markers in selected genes for association with functional longevity of dairy cattle
<p>Abstract</p> <p>Background</p> <p>Longevity expressed as the number of days between birth and death is a trait of great importance for both human and animal populations. In our analysis we use dairy cattle to demonstrate how the association of Single Nucleotide Polymorphisms (SNPs) located within selected genes with longevity can be modeled. Such an approach can be extended to any genotyped population with time to endpoint information available. Our study is focused on selected genes in order to answer the question whether genes, known to be involved into the physiological determination of milk production, also influence individual's survival.</p> <p>Results</p> <p>Generally, the highest risk differences among animals with different genotypes are observed for polymorphisms located within the leptin gene. The polymorphism with a highest effect on functional longevity is LEP-R25C, for which the relative risk of culling for cows with genotype CC is 3.14 times higher than for the heterozygous animals. Apart from LEP-R25C, also FF homozygotes at the LEP-Y7F substitution attribute 3.64 times higher risk of culling than the YY homozygotes and VV homozygotes at LEP-A80V have 1.83 times higher risk of culling than AA homozygotes. Differences in risks between genotypes of polymorphisms within the other genes (the butyrophilin subfamily 1 member A1 gene, BTN1A1; the acyl-CoA:diacylglycerol acyltransferase 1 gene, DGAT1; the leptin receptor gene, LEPR; the ATP-binding cassette sub-family G member 2, ABCG2) are much smaller.</p> <p>Conclusions</p> <p>Our results indicate association between LEP and longevity and are very well supported by results of other studies related to dairy cattle. In view of the growing importance of functional traits in dairy cattle, LEP polymorphisms should be considered as markers supporting selection decisions. Furthermore, since the relationship between both LEP polymorphism and its protein product with longevity in humans is well documented, with our result we were able to demonstrate that livestock with its detailed records of family structure, genetic, and environmental factors as well as extensive trait recording can be a good model organism for research aspects related to humans.</p
Das Berufsfeldpraktikum in pädagogischen Einrichtungen des Elementarbereichs. Ein Modellkonzept für das Studium Sprachliche Grundbildung (Grundschullehramt Deutsch)
Der Beitrag skizziert und illustriert ein Konzept für die Professionalisierung von Lehramtsstudierenden im Fach Sprachliche Grundbildung an der Universität Duisburg-Essen, bei dem Studierende sprachliche Heterogenität in der praktischen Arbeit mit Kita-Kindern erleben und zugleich Sprachförderung in Kita und Schule vergleichen und reflektieren lernen. Aufgezeigt wird der Modellcharakter dieses Konzepts als Baustein der Professionalisierung angehender Lehrkräfte. (DIPF/Orig.
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