5,358 research outputs found

    Factors affecting accumulation of summer grass for winter standing feed in the high country

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    A 0.5 ha 6-year trial compared 6 grass species x 4 N fertiliser rates x 2 times of closing for summer-saved standing winter feed. The pre-winter yields averaged 3.4 t DM/ha from November, closing with a high browntop/sweet vernal component, as compared with 1.7 t DM/ha from December closings with a low browntop/sweet vernal component. Grasslands Kara cocksfoot was the highest yielding cultivar, followed by Grasslands Apanui cocksfoot, Grasslands Wana cocksfoot, Grasslands Roa tall fescue, Grasslands Nui perennial ryegrass and Grasslands Maru phalaris, with decreasing proportions of sown grass. Nitrogen fertiliser had a limited effect on prewinter yields but did have a carry-over effect into spring yields

    Multiple RNA-binding proteins function combinatorially to control the soma-restricted expression pattern of the E3 ligase subunit ZIF-1

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    AbstractIn C. elegans embryos, transcriptional repression in germline blastomeres requires PIE-1 protein. Germline blastomere-specific localization of PIE-1 depends, in part, upon regulated degradation of PIE-1 in somatic cells. We and others have shown that the temporal and spatial regulation of PIE-1 degradation is controlled by translation of the substrate-binding subunit, ZIF-1, of an E3 ligase. We now show that ZIF-1 expression in embryos is regulated by five maternally-supplied RNA-binding proteins. POS-1, MEX-3, and SPN-4 function as repressors of ZIF-1 expression, whereas MEX-5 and MEX-6 antagonize this repression. All five proteins bind directly to the zif-1 3′ UTR in vitro. We show that, in vivo, POS-1 and MEX-5/6 have antagonistic roles in ZIF-1 expression. In vitro, they bind to a common region of the zif-1 3′ UTR, with MEX-5 binding impeding that by POS-1. The region of the zif-1 3′ UTR bound by MEX-5/6 also partially overlaps with that bound by MEX-3, consistent with their antagonistic functions on ZIF-1 expression in vivo. Whereas both MEX-3 and SPN-4 repress ZIF-1 expression, neither protein alone appears to be sufficient, suggesting that they function together in ZIF-1 repression. We propose that MEX-3 and SPN-4 repress ZIF-1 expression exclusively in 1- and 2-cell embryos, the only period during embryogenesis when these two proteins co-localize. As the embryo divides, ZIF-1 continues to be repressed in germline blastomeres by POS-1, a germline blastomere-specific protein. MEX-5/6 antagonize repression by POS-1 and MEX-3, enabling ZIF-1 expression in somatic blastomeres. We propose that ZIF-1 expression results from a net summation of complex positive and negative translational regulation by 3′ UTR-binding proteins, with expression in a specific blastomere dependent upon the precise combination of these proteins in that cell

    Towards a developmental state? Provincial economic policy in South Africa

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    This paper explores the meaning of the developmental state for spatial economic policy in South Africa. Two main questions are addressed: do provincial governments have a role to play in promoting economic prosperity, and to what extent do current provincial policies possess the attributes of a developmental state? These attributes are defined as the ability to plan longer term, to focus key partners on a common agenda, and to mobilise state resources to build productive capabilities. The paper argues that the developmental state must harness the power of government at every level to ensure that each part of the country develops to its potential. However, current provincial capacity is uneven, and weakest where support is needed most. Many provinces seem to have partial strategies and lack the wherewithal for sustained implementation. Coordination across government appears to be poor. The paper concludes by suggesting ways provincial policies could be strengthened

    Overview of the spectrometer optical fiber feed for the Habitable-zone Planet Finder

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    The Habitable-zone Planet Finder (HPF) is a highly stabilized fiber fed precision radial velocity (RV) spectrograph working in the Near Infrared (NIR): 810 - 1280 nm . In this paper we present an overview of the preparation of the optical fibers for HPF. The entire fiber train from the telescope focus down to the cryostat is detailed. We also discuss the fiber polishing, splicing and its integration into the instrument using a fused silica puck. HPF was designed to be able to operate in two modes, High Resolution (HR- the only mode mode currently commissioned) and High Efficiency (HE). We discuss these fiber heads and the procedure we adopted to attach the slit on to the HR fibers.Comment: Presented at 2018 SPIE Astronomical Telescopes + Instrumentation, Austin, Texas, USA. 18 pages, 25 figures, and 2 table

    An Optical Backplane Demonstrator System Based on FET-SEED Smart Pixel Arrays and Diffractive Lenslet Arrays

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    We have demonstrated a representative portion of an optical backplane using FET-SEED smart pixels and free-space optics to interconnect printed circuit boards (PCB\u27s) in a two board, unidirectional link configuration. 4×4 arrays of FET-SEED transceivers were designed, fabricated, and packaged all the PCB level, The optical interconnection was constructed using diffractive microoptics, and custom optomechanics. The system was operated in two modes, one showing high data throughput, 100 MBit/sec, and the other demonstrating large connection densities, 2222 channel/cm2

    Electronic structure and ferroelectricity in SrBi2Ta2O9

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    The electronic structure of SrBi2Ta2O9 is investigated from first-principles, within the local density approximation, using the full-potential linearized augmented plane wave (LAPW) method. The results show that, besides the large Ta(5d)-O(2p) hybridization which is a common feature of the ferroelectric perovskites, there is an important hybridization between bismuth and oxygen states. The underlying static potential for the ferroelectric distortion and the primary source for ferroelectricity is investigated by a lattice-dynamics study using the Frozen Phonon approach.Comment: 17 pages, 7 figures. Phys. Rev. B, in pres

    Selection of Psyllid-Resistant Forage Varieties from an Inter-Specific Breeding Program of \u3cem\u3eLeucaena leucocephala\u3c/em\u3e with \u3cem\u3eL. pallida\u3c/em\u3e

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    Leucaena (Leucaena leucocephala) pastures for beef cattle production are productive and sustainable; however, susceptibility to the psyllid insect (Heteropsylla cubana) has limited expansion of current commercial cultivars into more humid areas (\u3e 800 mm/yr) (Shelton and Dalzell 2007). Psyllids can also cause intermittent damage in lower rainfall regions during humid periods. The psyllid, which arrived in Australia in 1986, is a leaf-sucking insect specific to the Leucaena genus, feeding on the growing tips of susceptible cultivars (Bray 1994). Psyllid damage can reduce production by as much as 50-70% in humid regions and 20-50% in subhumid environments (Bray 1994; Mullen and Shelton 2003). Work on psyllid resistance in the Leucaena genus through the 1990s showed that several Leucaena species, including the tetraploid L. pallida, had good levels of resistance (Mullen et al. 2003). A breeding program to develop psyllid-resistant varieties began in 2002 at The University of Queensland (UQ) based on the F1 inter-specific hybrids between L. leucocephala and L. pallida (known as ‘KX2’), developed at the University of Hawaii (Brewbaker 2008). Between 2002 and 2005, UQ initiated a program of recurrent selection in an attempt to produce stable outcrossed KX2-derived lines but inbreeding depression for yield and poor forage quality led to a change in the breeding strategy, and a backcrossing program was implemented between 2005 and 2008. Two cycles of backcrossing to elite L. leucocephala ssp. glabrata material were completed followed by 2 cycles of progeny testing and selection for self-compatibility to achieve stability and uniformity (2009 - 2012). Forty elite psyllid-resistant lines were then evaluated to identify the most suitable lines for release to industry. This paper describes the results of these trials

    Regulation of Corticosteroidogenic Genes by MicroRNAs

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    The loss of normal regulation of corticosteroid secretion is important in the development of cardiovascular disease. We previously showed that microRNAs regulate the terminal stages of corticosteroid biosynthesis. Here, we assess microRNA regulation across the whole corticosteroid pathway. Knockdown of microRNA using Dicer1 siRNA in H295R adrenocortical cells increased levels of CYP11A1, CYP21A1, and CYP17A1 mRNA and the secretion of cortisol, corticosterone, 11-deoxycorticosterone, 18-hydroxycorticosterone, and aldosterone. Bioinformatic analysis of genes involved in corticosteroid biosynthesis or metabolism identified many putative microRNA-binding sites, and some were selected for further study. Manipulation of individual microRNA levels demonstrated a direct effect of miR-125a-5p and miR-125b-5p on CYP11B2 and of miR-320a-3p levels on CYP11A1 and CYP17A1 mRNA. Finally, comparison of microRNA expression profiles from human aldosterone-producing adenoma and normal adrenal tissue showed levels of various microRNAs, including miR-125a-5p to be significantly different. This study demonstrates that corticosteroidogenesis is regulated at multiple points by several microRNAs and that certain of these microRNAs are differentially expressed in tumorous adrenal tissue, which may contribute to dysregulation of corticosteroid secretion. These findings provide new insights into the regulation of corticosteroid production and have implications for understanding the pathology of disease states where abnormal hormone secretion is a feature
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