1,049 research outputs found
Hardship and Collective Violence in France: 1830 to 1960
http://deepblue.lib.umich.edu/bitstream/2027.42/50853/1/72.pd
The CArG Boxes in the Promoter of the Arabidopsis Floral Organ Identity Gene APETALA3 Mediate Diverse Regulatory Effects
APETALA3 is a MADS box gene required for normal development of the petals and stamens in the Arabidopsis flower. Studies in yeast, mammals and plants demonstrate that MADS domain transcription factors bind with high affinity to a consensus sequence called the CArG box. The APETALA3 promoter contains three close matches to the consensus CArG box sequence. To gain insights into the APETALA3 regulatory circuitry, we have analyzed the APETALA3 promoter using AP3::uidA(GUS) fusions. 496 base pairs of APETALA3 promoter sequence 5âČ to the transcriptional start directs GUS activity in the same temporal and spatial expression pattern as the APETALA3 RNA and protein in wild-type flowers. A synthetic promoter consisting of three tandem repeats of a 143 base pair sequence directs reporter gene activity exclusively to
INTRODUCTION
The developmental fate of the organs in the Arabidopsis flower is controlled by the homeotic floral organ identity genes. When the activity of a particular floral organ identity gene is lost due to mutation, there is a homeotic conversion of one organ type to another. For example, the APETALA3 (AP3) and PISTILLATA (PI) genes are necessary for the proper development of petals that develop in the second whorl and stamens that develop in the third whorl of the flower. In ap3 and pi mutants, sepals and carpels develop in positions normally occupied by petals and stamens respectively (Bowman et al., 1989; Jack et al., 1992). Accumulating genetic and molecular evidence suggests that the AP3 and PI proteins together make up the B class organ identity function and these two proteins are sufficient to direct the identity of petals and stamens in the flower. In support of this, ectopic expression of AP3 and/or PI throughout the flower leads to homeotic transformations. Specifically misexpression of AP3 (i.e. 35S::AP3) results in the development of stamens in place of carpels in the fourth whorl and misexpression of PI (i.e. 35S::PI) results in the development of petaloid sepals in place of sepals in the first whorl of the flower (Jack et al., 1994; Krizek and Meyerowitz, 1996). 35S::AP3 leads to fourth whorl organ identity changes because PI is transiently expressed in whorl four during early stages of flower
petals and stamens in the flower. We have analyzed the role of the CArG boxes by site-specific mutagenesis and find that the three CArG boxes mediate discrete regulatory effects. Mutations in CArG1 result in a decrease in reporter expression suggesting that CArG1 is the binding site for a positively acting factor or factors. Mutations in CArG2 result in a decrease in reporter expression in petals, but the expression pattern in stamens is unchanged. By contrast, mutations in CArG3 result in an increase in the level of reporter gene activity during early floral stages suggesting that CArG3 is the binding site for a negatively acting factor
Acceptance and Commitment Therapy (ACT) for people with advanced progressive illness, their caregivers and staff involved in their care:A scoping review
Photoelectric sensor for fast and low-priced determination of bi- and triphasic segmented slug flow parameters
Applying multiphase systems in microreactors leads to an intensification of heat and mass transport. Critical aspects of the well-studied segmented slug-flow, such as bubble generation and pump control, can be automated, provided a robust sensor for the reliable determination of velocity, phase lengths, and phase ratio(s) is available. In this work, a fast and low-priced sensor is presented, based on two optical transmission sensors detecting flow characteristics noninvasively together with a microcontroller. The resulting signal is mainly due to refraction of the bubble-specific geometries as shown by a simulation of light paths. The high performance of the processing procedure, utilizing the derivative of the signal, is demonstrated for a bi- and triphasic slug flow. The error of <5% is entirely reasonable for the purpose envisaged. The sensor presented is very fast, robust, and inexpensive, thus enhancing the attractiveness of parallelized capillary reactors for industrial applications
Heterogeneous Scintillator Geometries to Maximise Energy Deposition for Waterborne Beta Particle Detection
Here the geometries that maximise detection efficiency of heterogeneous scintillators used to detect beta particles in aqueous solutions by maximising energy deposition are described. The determination of the geometry was achieved with the Monte Carlo code Geant4 using CaF2:Eu scintillator as a pertinent case study, and validated with experimental data using single crystal CaF2:Eu and heterogeneous CaF2:Eu scintillators. Both 2D and 3D structures composed of arrays of primitive unit cells of packed spheres were examined to find the optimal geometry to maximise detection of volumetric sources of tritium and aqueous Carbon 14 and Lead 210. The 2D structures were evaluated relative to a single crystal scintillator and results show the detection efficiency of the 2D structures is maximised when the sphere radius is c.a. 0.46x the maximum track length of the beta particle in the scintillator. Data for the 3D structures show that the efficiency is maximised when the sphere radius is minimised, but it is further shown that practical issues limit the minimum radius that can be used for transient radiological contamination monitoring
A molecular communication channel consisting of a single reversible chain of hydrogen bonds in a conformationally flexible oligomer
Communication of information through the global switching of conformation in synthetic molecules has hitherto entailed the inversion of chirality. Here, we report a class of oligomer through which information may be communicated through a global reversal of polarity. Ethylene-bridged oligoureas are constitutionally symmetrical, conformationally flexible molecules organized by a single chain of hydrogen bonds running the full length of the oligomer. NMR reveals that this hydrogen-bonded chain may undergo a coherent reversal of directionality. The directional uniformity of the hydrogen-bond chain allows it to act as a channel for the spatial communication of information on a molecular scale. A binding site at the terminus of an oligomer detects local information about changes in pH or anion concentration and transmits that informationâin the form of a directionality switch in the hydrogen-bond chainâto a remote polarity-sensitive fluorophore. This propagation of polarity-encoded information provides a new mechanism for molecular communication
Inferenzstatistische Modellierung der Dynamik bipartiter Netzwerke am Beispiel einer online Reiseplattform
Ziel dieses Beitrages ist die Vorstellung einer inferenzstatistischenMethode zur Modellierung der Dynamik bipartiterNetzwerke. Exemplarisch wird die Methode an einem bipartitenNetzwerk aus Reisezielen und Benutzern einer onlineReiseplattform illustriert. Unser akteursbasiertes Modell untersuchtdabei Faktoren, die Einuss darauf haben, zu welchemReiseziel ein Benutzer der Reiseplattform (wie z.B.www.tripadvisor.com) einen Reisebericht schreibt. Fur denZeitraum von 2006 bis 2009 wurden mehrere bipartite Netzwerkemodelliert, deren Knoten durch Benutzer und Reisezieleund deren Kanten durch Reiseberichte reprasentiertwurden. Dieser Ansatz ist, nach unserer Kenntnis, die ersteinferenzstatistische Modellierung der Dynamik eines bipartitenNetzwerks zur Untersuchung des Reiseverhaltens vonAkteuren. Er kann von Wissenschaftlern und Unternehmenweiterentwickelt werden, um Reisestrome vorherzusagen. Dadie Modellierung der Dynamik von (bi-)partiten Netzwerkenfur eine Vielzahl von Fragestellungen in der WirtschaftsinformatikRelevanz hat, liegt der Schwerpunkt dieses Artikelsweniger auf der inhaltlichen Interpretation der Ergebnisseals auf der grundlegenden Darstellung der Modellklasse
Diasporas and secessionist conflicts : the mobilization of the Armenian, Albanian and Chechen diasporas
This article examines the impact of diasporas on secessionist conflicts, focusing on the Albanian, Armenian and Chechen diasporas and the conflicts in Kosovo, Karabakh and Chechnya during the 1990s. How do diasporas radicalize these conflicts? I argue that despite differences in diaspora communal characteristics and the types of the secessionist conflicts, a common pattern of mobilization develops. Large-scale diasporic support for secessionism emerges only after independence is proclaimed by the local elites. From that point onwards diasporas become engaged in a conflict spiral, and transnational coalitions are formed between local secessionist and diaspora groups. Depending on the organizational strength of the local strategic centre and the diasporic institutions, these coalitions endure or dissipate. Diasporas exert radicalization influences on the conflict spiral on two specific junctures â when grave violations of human rights occur in the homeland and when local moderate elites start losing credibility that they can achieve the secessionist goal
Review Essay : The Family and Migration: News From the Frencn
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67023/2/10.1177_036319908601100205.pd
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