690 research outputs found
General lack of global dosage compensation in ZZ/ZW systems? Broadening the perspective with RNA-seq
No full textAbstract Background Species with heteromorphic sex chromosomes face the challenge of large-scale imbalance in gene dose. Microarray-based studies in several independent male heterogametic XX/XY systems suggest that dosage compensation mechanisms are in place to mitigate the detrimental effects of gene dose differences. However, recent genomic research on female heterogametic ZZ/ZW systems has generated surprising results. In two bird species and one lepidopteran no evidence for a global dosage compensating mechanism has been found. The recent advent of massively parallel RNA sequencing now opens up the possibility to gauge the generality of this observation with a broader phylogenetic sampling. It further allows assessing the validity of microarray-based inference on dosage compensation with a novel technology. Results We here expemplify this approach using massively parallel sequencing on barcoded individuals of a bird species, the European crow (Corvus corone), where previously no genetic resources were available. Testing for Z-linkage with quantitative PCR (qPCR,) we first establish that orthology with distantly related species (chicken, zebra finch) can be used as a good predictor for chromosomal affiliation of a gene. We then use a digital measure of gene expression (RNA-seq) on brain transcriptome and confirm a global lack of dosage compensation on the Z chromosome. RNA-seq estimates of male-to-female (m:f) expression difference on the Z compare well to previous microarray-based estimates in birds and lepidopterans. The data further lends support that an up-regulation of female Z-linked genes conveys partial compensation and suggest a relationship between sex-bias and absolute expression level of a gene. Correlation of sex-biased gene expression on the Z chromosome across all three bird species further suggests that the degree of compensation has been partly conserved across 100 million years of avian evolution. Conclusions This work demonstrates that the study of dosage compensation has become amenable to species where previously no genetic resources were available. Massively parallele transcriptome sequencing allows re-assessing the degree of dosage compensation with a novel tool in well-studies species and, in addition, gain valuable insights into the generality of mechanisms across independent taxonomic group for both the XX/XY and ZZ/ZW system.</p
Sedimentstrategie voor de ZW Delta: een verkenning van kansen
No full textIn deze studie worden de ontwikkelingen in de sedimenthuishouding als uitgangspunt beschouwd voor duurzame inrichting van de ZW Delta. Centraal staan de kansen van een sedimentstrategie: het gericht beïnvloeden van de sedimenthuishouding, met het oog op het bereiken van een of meer (beleids)doelen
Evolution of a ZW sex chromosome system in willows
No full text© 2023, The Author(s). cc-byTransitions in the heterogamety of sex chromosomes (e.g., XY to ZW or vice versa) fundamentally alter the genetic basis of sex determination, however the details of these changes have been studied in only a few cases. In an XY to ZW transition, the X is likely to give rise to the W because they both carry feminizing genes and the X is expected to harbour less genetic load than the Y. Here, using a new reference genome for Salix exigua, we trace the X, Y, Z, and W sex determination regions during the homologous transition from an XY system to a ZW system in willow (Salix). We show that both the W and the Z arose from the Y chromosome. We find that the new Z chromosome shares multiple homologous putative masculinizing factors with the ancestral Y, whereas the new W lost these masculinizing factors and gained feminizing factors. The origination of both the W and Z from the Y was permitted by an unexpectedly low genetic load on the Y and this indicates that the origins of sex chromosomes during homologous transitions may be more flexible than previously considered
Outflows in the radio-intermediate quasar III Zw 2: A polarization study with the EVLA and uGMRT
No full text\ua9 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.We present results from a polarization study of the radio-intermediate quasar, III Zw 2, at a redshift of 0.089, with the upgraded Giant Metrewave Radio Telescope (uGMRT) at 685 MHz and the Karl G. Jansky Very Large Array (VLA) at 5 and 34 GHz. We detect a kpc-scale outflow, exhibiting transverse magnetic (B-) fields. The curved jet terminates in a bow-shock-like radio structure with inferred B-fields aligned with the lobe edges. We suggest that the radio outflow in III Zw 2 is a combination of a collimated jet along with a wind-like component. This \u27wind\u27 component could be a magnetized accretion disc wind or the outer layers of a broadened jet or a combination of both. The current data cannot differentiate between these possibilities. We also detect kpc-scale lobe emission that is misaligned with the primary lobes in the uGMRT images. The spectral indices and the electron lifetimes in the misaligned lobe are similar to the primary lobe, suggesting that the misaligned lobe is not a relic. We propose that changing spectral states of the accretion disc, and the subsequent intermittent behaviour of the outflow, along with the close interplay between the jet and \u27wind\u27 could explain the radio-intermediate nature of III Zw 2. Our study shows that radio-intermediate quasars are promising sources for understanding the role of jets and winds in galaxy evolution and demonstrates the power of radio polarization studies towards achieving this
Spin-flip relaxation in a two-electron quantum dot with spin-phonon coupling
No full textWe study the spin-flip process from the first excited state to the ground state due to the spin-phonon coupling in a two-electron quantum dot in the presence of a magnetic field. We give several possible relaxation channels before and after the crossing of the Zeeman sublevels. Our results show that the Coulomb interactions between the electrons of different channels play quite different roles and thus inducing different spin relaxation behaviors. (C) 2011 Elsevier Ltd. All rights reserved
Effective channels of breaking the phonon bottleneck: A lattice relaxation approach
No full textWe theoretically study the relaxation of electron orbital states of a quantum dot due to two-phonon processes by applying a lattice relaxation approach based on a multimode description for the electron-phonon interaction. The fast relaxation time is obtained in a large energy detuning around the longitudinal optical phonon energy. This model offers an effective channel to break the phonon bottleneck. We calculate the lattice temperature and energy separation dependence of the relaxation time for different two-phonon scattering channels and obtain a good agreement with the available experimental measurement for the phonon bottleneck in quantum dots. (C) 2011 American Institute of Physics. [doi:10.1063/1.3624610
Ontwikkeling geulwandsuppletie ZW-Texel (Molengat)
No full textIn dit rapport worden de resultaten beschreven van een onderzoek naar het morfologisch gedrag van de in 2003 uitgevoerde suppletie op de zuidwestkust van Texel (RSP 9 km - RSP 11,5 km) in het Molengat. Het onderzoek is gebaseerd op gedetailleerde peilingen die vlak voor en direct na uitvoering van de suppletie zijn gedaan, alsmede op één peiling ruim een half jaar na oplevering. Voorts is gebruik gemaakt van beschikbare gegevens en gebiedskennis en zijn verkennende berekeningen gemaakt met een morfologisch model van het Zeegat van Texel. Een belangrijke constatering is dat de suppletie in het golf-gedomineerde gebied ligt. Het morfologisch gedrag past meer bij dat van een vooroeversuppietie dan bij een geulwandsuppletie. De effecten op het grootschalige patroon van geulen en platen op de buitendelta van het zeegat zijn nihil. Het suppletiezand (1,2 miljoen m3) wordt langs de zuidwestkust van Texel verspreid. Dit leidt de komende jaren tot een netto aangroei van de kust ongeveer tussen RSP 8 km en RSP 12 km. Na een periode van 3 tot 7 jaar zal als gevolg van de doorgaande kusterosie opnieuw moeten worden gesuppleerd. Op een termijn van ongeveer tien jaar kan een natuurlijke aangroei van de kust verwacht worden van zand dat afkomstig is van de noordelijke uitlopers van de Noorderhaaks. Die aanlanding staat los van de hier geëvalueerde suppletie.A135
De strijd tegen de verzouting van ons polderland
No full textAbstract Kort exposé over de effecten van de verzilting in ZW Nederland door zout water van zee en door de toenemende verzilting van de Rijn
Research on the impact of air-blowing on aerodynamic drag reduction and wake characteristics of a high-speed maglev train
No full textAuthor name used in this publication: 车正鑫Author name used in this publication: 陈争卫Author name used in this publication: 倪一清Author name used in this publication: 黄莎Author name used in this publication: 李志伟202407 bcchVersion of RecordRGCPublishedVoR allowe
The Pauline traditions in the acts of apostles
No full textPart I. The theme of Pauline tradition is mentioned by Barrett and Schenke, and further, Roloff and Plamacher indicate traditional material behind the image of Paul in Acts, part of which is analyzed by burchard and Loning (ch.l). The date of Acts is placed at the end of the first century and the author confronted Jewish Christianity crossed with Gnosticism (ch.2), Historical criticism, form criticism and redaction criticism are methodological principles for our investigation. Any source theories are problematical. However, the author utilized traditional material in depiction of Paul in Acts, namely, the Pauline traditions, which are parallel to the Pauline Epistles, the Pauline legends, which are parallel to the miracle stories in the synoptic tradition, and the local community traditions (ch.5).Part II. Paul's background in Acts (Jewish, Hellenistic and Roman) is based on the Pauline traditions. Judaizing and anti-Jewish tendencies are seen in it (ch.4), Paul's pre-conversion period is also based on the Pauline traditions, but coloured with Judaizing tendencies (ch.3). Paul's conversion and call are due to traditional material, out modified with literary devices. Anti-gnostic tendencies can be traced behind it (ch.6). The earliest years after conversion and call are based on tradition; however, it is dominated by anti-Jewish tendencies (ch.7). The first missionary journey is not totally a "model” journey, but two parts of it are based on the Pauline traditions respectively together with the Pauline legends. But the author arranged them in order to make a circular journey. Judaizing tendencies and ambivalent anti-Jewish tendencies are seen in it (ch.8). In the second missionary journey, in contrast to the first one, the local community traditions are employed together with the Pauline traditions and the Pauline legends. Judaizing tendencies are seen in it (ch.9). The Pauline traditions, the Pauline legends and the local community traditions are utilized in the depiction of the third missionary journey. Apologetic tendencies against syncretism and paganism are seen in it (ch.lO). The image of Paul in Acts is not only based on traditional material but also transformed by the author in order to defend the legitimacy of the Gentile mission under anti-Pauline attacks. Acts is governed by rhetorical Peripatetic historiography (ch.11)
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