177 research outputs found

    Threatened forests As the Northern forests suffer from the effects of climate change, genomics has great potential to help them adapt

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    Climate change is having dramatic effects on forest health and growth - tree genomics provides tools for understanding and mitigating these effects

    Analysis of Heavy Metals in Mouse Uterine Secretion by X-Ray Microanalysis

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    A method for the detection of heavy metal ions in the uterine secretion of the mouse was tested. Mice received an intravenous injection of lead, and beads of an analytical grade resin, Chelex 100, were deposited in the uterine lumen to absorb heavy metals present in the secretion. X-ray microanalysis of the flushed beads showed that lead was present in a dose-related way in the uterine secretion of mice that had received 0.05, 0.1, or 0.15 mg lead per g body weight. Thus, the technique allows quantitative analysis of lead in the uterine secretion. The amount of lead present in the secretion decreased with time after the application of lead

    Gait analysis of unprovoked pig gait on clean and fouled concrete surfaces

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    Inadequate floor properties are considered the primary cause of the majority of claw disorders in pigs but to date no clear relationship has been found between claw disorders and floor properties such as friction and surface abrasiveness. To determine this relationship, the factors controlling pig gait must be characterised. This study examined unprovoked pig gait on a concrete floor in clean conditions and compared it with gait in fouled floor conditions. Kinematics were used to record gait parameters such as walking speed, stride length, swing and stance time, stride elevation together with limb support phases, gait symmetry, diagonality and duty factor. On clean floors, pigs had an unprovoked symmetrical gait with alternating two- and three-beat support phases and a high rate of diagonality. Stride length, swing and stance time and stride elevation showed little variation. Pigs altered their gait in accordance with floor conditions to maintain gait control by reducing walking speed, lowering diagonality and employing more three-limb support phases. Pigs also shortened their stride length and prolonged their stance time

    Hardware architecture of an SVD based MIMO OFDM channel estimator

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    Age-dependent seasonal growth cessation in Populus

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    In temperate and boreal regions, perennial plants adapt their annual growth cycle to the change of seasons. In natural forests, juvenile seedlings usually display longer growth seasons compared to adult trees to ensure their establishment and survival under can-opy  shade.  However,  how  trees  adjust  their  annual  growth  according  to  their  age  is  not  known.  In  this  study,  we  show  that  age- dependent  seasonal  growth  cessation  is  genetically  controlled  and  found  that  the  miR156- SPL3/5  module,  a  key  regulon  of  vegetative phase change (VPC), also triggers age- dependent growth cessation in Populustrees. We show that miR156 promotes shoot elongation during vegetative growth, and its targets SPL3/5s function in the same pathway but as repressors. We find that the miR156- SPL3/5s  regulon  controls  growth  cessation  in  both  leaves  and  shoot  apices  and  through  multiple  pathways,  but  with  a  different  mechanism  compared  to  how  the miR156- SPL regulon controls VPC in annual plants. Taken together, our results reveal an age- dependent genetic network in mediating seasonal growth cessation, a key phenological process in the climate adaptation of perennial trees

    A High-Speed QR Decomposition Processor for Carrier-Aggregated LTE-A Downlink Systems

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    This paper presents a high-speed QR decomposition (QRD) processor targeting the carrier-aggregated 4 × 4 Long Term Evolution-Advanced (LTE-A) receiver. The processor provides robustness in spatially correlated channels with reduced complexity by using modifications to the Householder transform, such as decomposing-target redefinition and matrix real-valued decomposition. In terms of hardware design, we extensively explore flexibilities in systolic architectures using a high-level synthesis tool to achieve area-power efficiency. In a 65 nm CMOS technology, the processor occupies a core area of 0.77mm2 and produces 72MQRD per second, the highest reported throughput. The power consumed in the proposed processor is 219mW

    Low temperatures are required to induce the development of fertile flowers in transgenic male and female early flowering poplar (Populus tremula L.)

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    Until now, artificial early flowering poplar systems have mostly led to the development of sterile flowers. In this study, several strategies aimed at inducting fertile flowers in pHSP::AtFT transgenic poplar were evaluated, in particular the influence of temperature and photoperiod. Our results provide evidence that temperature, and not photoperiod, is the key factor required for the development of fertile flowers in early flowering poplar. Fertile flowers were only obtained when a cold treatment phase of several weeks was used after the heat treatment phase. Heat treatments induced AtFT gene activity through activation of the heat-shock promoter (pHSP). Photoperiod did not show a similar influence on flower fertility as pollen grains were obtained under both long- and short-day conditions. Fertility was confirmed in flowers of both male and female plants. For the first time, crosses were successfully performed with transgenic female early flowering poplar. All mature flowers obtained after 8 weeks of inductive treatments were fertile. Gene expression studies also confirmed that cold temperatures influenced expression of poplar genes homologous to 'pollen development genes' from Arabidopsis thaliana (L.) Heynh. Homology and expression patterns suggested a role for PtTDF1, PtBAM1, PtSERK1/2 and PtMS1 on anther and pollen development in poplar flowers. The system developed in this study allows a fast and very reliable induction of fertile poplar flowers in a very short period of time. The non-reproductive phase, usually 7-10 years, can now be shortened to 6-10 months, and fertile flowers can be obtained independently of the season. This system is a reliable tool for breeding purposes (high-speed breeding technology), genomics and biosafety research.Facultad de Ciencias Agrarias y Forestale

    Low temperatures are required to induce the development of fertile flowers in transgenic male and female early flowering poplar (Populus tremula L.)

    Get PDF
    Until now, artificial early flowering poplar systems have mostly led to the development of sterile flowers. In this study, several strategies aimed at inducting fertile flowers in pHSP::AtFT transgenic poplar were evaluated, in particular the influence of temperature and photoperiod. Our results provide evidence that temperature, and not photoperiod, is the key factor required for the development of fertile flowers in early flowering poplar. Fertile flowers were only obtained when a cold treatment phase of several weeks was used after the heat treatment phase. Heat treatments induced AtFT gene activity through activation of the heat-shock promoter (pHSP). Photoperiod did not show a similar influence on flower fertility as pollen grains were obtained under both long- and short-day conditions. Fertility was confirmed in flowers of both male and female plants. For the first time, crosses were successfully performed with transgenic female early flowering poplar. All mature flowers obtained after 8 weeks of inductive treatments were fertile. Gene expression studies also confirmed that cold temperatures influenced expression of poplar genes homologous to 'pollen development genes' from Arabidopsis thaliana (L.) Heynh. Homology and expression patterns suggested a role for PtTDF1, PtBAM1, PtSERK1/2 and PtMS1 on anther and pollen development in poplar flowers. The system developed in this study allows a fast and very reliable induction of fertile poplar flowers in a very short period of time. The non-reproductive phase, usually 7-10 years, can now be shortened to 6-10 months, and fertile flowers can be obtained independently of the season. This system is a reliable tool for breeding purposes (high-speed breeding technology), genomics and biosafety research.Facultad de Ciencias Agrarias y Forestale

    Peptide encoding Populus CLV3/ESR-RELATED 47 (PttCLE47) promotes cambial development and secondary xylem formation in hybrid aspen

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    The CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (ESR)-RELATED (CLE) peptide ligands in connection with their receptors are important players in cell-to-cell communications in plants. Here, we investigated the function of the Populus CLV3/ESR-RELATED 47 (PttCLE47) gene during secondary growth and wood formation in hybrid aspen (Populus tremula x tremuloides) using an RNA interference (RNAi) approach. Expression of PttCLE47 peaks in the vascular cambium. Silencing of the PttCLE47 gene expression affected lateral expansion of stems and decreased apical height growth and leaf size. In particular, PttCLE47 RNAi trees exhibited a narrower secondary xylem zone with less xylem cells/cell file. The reduced radial growth phenotype also correlated with a reduced number of cambial cell layers. In agreement with these results, expression of several cambial regulator genes was downregulated in the stems of the transgenic trees in comparison with controls. Altogether, these results suggest that the PttCLE47 gene is a major positive regulator of cambial activity in hybrid aspen, mainly promoting the production of secondary xylem. Furthermore, in contrast to previously characterized CLE genes expressed in the wood-forming zone, PttCLE47 appears to be active at its site of expression.Peer reviewe

    Sensitization to Skin-associated Microorganisms in Adult Patients with Atopic Dermatitis is of Importance for Disease Severity.

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    Atopic dermatitis (AD) is a chronic inflammatory skin disease. Environmental and genetic factors, as well as microbial products from yeasts and bacteria, play a role in triggering the disease. A cohort of 619 adult patients with AD was screened for severity of AD, sensitization to Malassezia sympodialis, Candida albicans, Staphylococcus aureus enterotoxins and Dermatophagoides pteronyssinus. Serum levels of interleukin (IL)-18 were measured. Immunoglobulin E (IgE) sensitization to the combination of both yeast and mite antigens was found to be associated with more severe disease and higher levels of total IgE. AD patients with IgE sensitization to several microbial antigens had more severe disease than those with no IgE sensitization to microbial antigens. Sera from patients with IgE-associated AD showed higher levels of IL-18. Skin-associated microorganisms are exogenous factors triggering IgE-response and severity of AD. These findings are clinically important, and sensitization to these organisms should be assessed and considered in treatment strategies
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