UV-B perceived by the UVR8 photoreceptor inhibits plant thermomorphogenesis

Small increases in ambient temperature can elicit striking effects on plant architecture, collectively termed thermomorphogenesis [1]. In Arabidopsis thaliana, these include marked stem elongation and leaf elevation, responses that have been predicted to enhance leaf cooling [ 2, 3, 4 and 5]. Thermomorphogenesis requires increased auxin biosynthesis, mediated by the bHLH transcription factor PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) [ 6, 7 and 8], and enhanced stability of the auxin co-receptor TIR1, involving HEAT SHOCK PROTEIN 90 (HSP90) [9]. High-temperature-mediated hypocotyl elongation additionally involves localized changes in auxin metabolism, mediated by the indole-3-acetic acid (IAA)-amido synthetase Gretchen Hagen 3 (GH3).17 [10]. Here we show that ultraviolet-B light (UV-B) perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8) [11] strongly attenuates thermomorphogenesis via multiple mechanisms inhibiting PIF4 activity. Suppression of thermomorphogenesis involves UVR8 and CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1)-mediated repression of PIF4 transcript accumulation, reducing PIF4 abundance. UV-B also stabilizes the bHLH protein LONG HYPOCOTYL IN FAR RED (HFR1), which can bind to and inhibit PIF4 function. Collectively, our results demonstrate complex crosstalk between UV-B and high-temperature signaling. As plants grown in sunlight would most likely experience concomitant elevations in UV-B and ambient temperature, elucidating how these pathways are integrated is of key importance to the understanding of plant development in natural environments

DAWN Mission Bus and Waveguide Venting Analysis Review

A concern was raised regarding the time after launch when the DAWN Mission Communications Subsystem, which contains a 100 Watt X-Band Traveling Wave Tube Amplifier (TWTA) with a high voltage ((approximately 7 Kilo Volt (KV)) Electronic Power Converter (EPC), will be powered on for the first post-launch downlink. This activation is planned to be approximately one hour after launch. Orbital Sciences (the DAWN Mission spacecraft contractor) typically requires a 24-hour wait period prior to high voltage initiation for Earth-orbiting Science and GEO spacecraft. The concern relates to the issue of corona and/or radio frequency (RF) breakdown of the TWTA ((high voltage direct current (DC) and RF)), and of the microwave components (high voltage RF) in the presence of partial atmospheric pressures or outgassing constituents. In particular, generally the diplexer and circulator are susceptible to RF breakdown in the corona region due to the presence of small physical gaps ((~ 2.5 millimeter (mm)) between conductors that carry an RF voltage. The NESC concurred the DAWN Mission communication system is safe for activation

Anthropogenic, direct pressures on coastal wetlands

Coastal wetlands, such as saltmarshes and mangroves that fringe transitional waters, deliver important ecosystem services that support human development. Coastal wetlands are complex social-ecological systems that occur at all latitudes, from polar regions to the tropics. This overview covers wetlands in five continents. The wetlands are of varying size, catchment size, human population and stages of economic development. Economic sectors and activities in and around the coastal wetlands and their catchments exert multiple, direct pressures.Chinese Academy of Sciences (CAS-YIC) scholarship and SKLECECNU project 111 scholarship<, Natural Resources Canada contribution no. 20200070; Fundação para a Ciência e a Tecnologia (FCT) Scientific Employment Stimulus Programme (CEECIND/01635/2017). and (CEECIND/00095/2017), (UID/MAR/00350/2019CIMA) and (UID/MAR/04292/2019)info:eu-repo/semantics/publishedVersio

The relations of the Amampondo and the colonial authorities (1830-1886) with special reference to the role of the Wesleyan missionaries

South African historiography has tended to follow the Great Trek and to avoid the area between the Kei River and Natal. As a result, hardly any attention has been given to an unspectacular but significant chapter in the story of relations between black and white in the nineteenth century. The purpose of this thesis is to explore this by-way, and to examine the relations of the Amampondo and the Colonial authorities at the Cape and Natal between 1830 and 1886. For the greater part of this period these relations were governed, nominally at least, by the Treaty of 1844, and an attempt has been made to assess its value as an Instrument regulating the dealings of a European power and a native tribe. The Treaty System, of which it formed a part, was the creature of a day. Built up between 1334 and 1844, it was swept away by the Frontier War of 1846 and the Bloemfontein Convention of 1854. It has therefore been necessary to ask why the Mpondo Treaty remained a living force for so many years after its counterparts had been abandoned. [Please see pdf. for full abstract.

Testing Identifiability and Specification in Instrumental Variable Models

The paper develops and explores tests, based on standard moment specifications, for the identifiability of parameters apparently estimable by instrumental variables. An asymptotic expansion under standard restrictive assumptions on the error distribution suggests a correction to the asymptotic distribution. A small sampling experiment indicates that the tests are of use.

UV-B Perceived by the UVR8 Photoreceptor Inhibits Plant Thermomorphogenesis

Small increases in ambient temperature can elicit striking effects on plant architecture, collectively termed thermomorphogenesis. In Arabidopsis thaliana, these include marked stem elongation and leaf elevation, responses that have been predicted to enhance leaf cooling. Thermomorphogenesis requires increased auxin biosynthesis, mediated by the bHLH transcription factor PHYTOCHROMEINTERACTING FACTOR 4 (PIF4), and enhanced stability of the auxin co-receptor TIR1, involving HEAT SHOCK PROTEIN 90 (HSP90). High-temperature-mediated hypocotyl elongation additionally involves localized changes in auxin metabolism, mediated by the indole-3-acetic acid (IAA)-amido synthetase Gretchen Hagen 3 (GH3).17 [10]. Here we show that ultraviolet-B light (UV-B) perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8) strongly attenuates thermomorphogenesis via multiple mechanisms inhibiting PIF4 activity. Suppression of thermomorphogenesis involves UVR8 and CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1)-mediated repression of PIF4 transcript accumulation, reducing PIF4 abundance. UV-B also stabilizes the bHLH protein LONG HYPOCOTYL IN FAR RED (HFR1), which can bind to and inhibit PIF4 function. Collectively, our results demonstrate complex crosstalk between UV-B and high-temperature signaling. As plants grown in sunlight would most likely experience concomitant elevations in UV-B and ambient temperature, elucidating how these pathways are integrated is of key importance to the understanding of plant development in natural environments