115 research outputs found

    Regulation of Ca2+ channel and phosphatase activities by polyamines in intestinal and vascular smooth muscle - implications for cellular growth and contractility.

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    Polyamines added extracellularly to intestinal and vascular smooth muscle cells cause relaxation through inhibition of Ca2+ channel activity. Intracellularly applied polyamines also affect Ca2+ channel properties. Polyamines do not readily pass over the plasma membrane because of their positive charges but in permeabilized smooth muscle preparations they have free access to the cytoplasm. In this system they increase sensitivity of the contractile machinery to Ca2+ through inhibition of myosin phosphatase activity. The magnitude of Ca2+ channel and phosphatase inhibition depends on the number of positive charges on the polyamine molecule. Polyamines have an obligatory, but yet undefined, role in regulation of cell growth and proliferation. Several groups of protein kinases, such as tyrosine and mitogen activated protein (MAP)-kinases transmit the growth signal from the plasma membrane to the cell nucleus where mitosis and protein synthesis are initiated. The data reviewed here show that polyamines may affect such signal transmission via inhibition of phosphatase activity

    Comparison of Automotive FMCW and OFDM Radar Under Interference

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    Automotive radars are subject to interference in spectrally congested environments. To mitigate this interference, various waveforms have been proposed. We compare two waveforms (FMCW and OFDM) in terms of their radar performance and robustness to interference, under similar parameter settings. Our results indicate that under proper windowing both waveforms can achieve similar performance, but OFDM is more sensitive to interference

    Radar Interference Mitigation for Automated Driving: Exploring Proactive Strategies

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    Autonomous driving relies on a variety of sensors, especially on radars, which have unique robustness under heavy rain/fog/snow and poor light conditions. With the rapid increase of the amount of radars used on modern vehicles, where most radars operate in the same frequency band, the risk of radar interference becomes a compelling issue. This article analyses automotive radar interference and proposes several new approaches, which combine industrial and academic expertise, toward the path of interference-free autonomous driving

    Cone-setting in spruce is regulated by conserved elements of the age-dependent flowering pathway

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    Reproductive phase change is well characterized in angiosperm model species, but less studied in gymnosperms. We utilize the early cone-setting acrocona mutant to study reproductive phase change in the conifer Picea abies (Norway spruce), a gymnosperm. The acrocona mutant frequently initiates cone-like structures, called transition shoots, in positions where wild-type P. abies always produces vegetative shoots. We collect acrocona and wild-type samples, and RNA-sequence their messenger RNA (mRNA) and microRNA (miRNA) fractions. We establish gene expression patterns and then use allele-specific transcript assembly to identify mutations in acrocona. We genotype a segregating population of inbred acrocona trees. A member of the SQUAMOSA BINDING PROTEIN-LIKE (SPL) gene family, PaSPL1, is active in reproductive meristems, whereas two putative negative regulators of PaSPL1, miRNA156 and the conifer specific miRNA529, are upregulated in vegetative and transition shoot meristems. We identify a mutation in a putative miRNA156/529 binding site of the acrocona PaSPL1 allele and show that the mutation renders the acrocona allele tolerant to these miRNAs. We show co-segregation between the early cone-setting phenotype and trees homozygous for the acrocona mutation. In conclusion, we demonstrate evolutionary conservation of the age-dependent flowering pathway and involvement of this pathway in regulating reproductive phase change in the conifer P. abies

    Linearization in ultrametric dynamics in fields of characteristic zero - equal characteristic case

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    Let KK be a complete ultrametric field of charactersitic zero whose corresponding residue field k\Bbbk is also of charactersitic zero. We give lower and upper bounds for the size of linearization disks for power series over KK near an indifferent fixed point. These estimates are maximal in the sense that there exist exemples where these estimates give the exact size of the corresponding linearization disc. Similar estimates in the remaning cases, i.e. the cases in which KK is either a pp-adic field or a field of prime characteristic, were obtained in various papers on the pp-adic case (Ben-Menahem:1988,Thiran/EtAL:1989,Pettigrew/Roberts/Vivaldi:2001,Khrennikov:2001) later generalized in (Lindahl:2009 arXiv:0910.3312), and in (Lindahl:2004 http://iopscience.iop.org/0951-7715/17/3/001/,Lindahl:2010Contemp. Math) concerning the prime characteristic case

    A trial to evaluate the effect of the sodium–glucose co‐transporter 2 inhibitor dapagliflozin on morbidity and mortality in patients with heart failure and reduced left ventricular ejection fraction (DAPA‐HF)

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    Background: Sodium–glucose co‐transporter 2 (SGLT2) inhibitors have been shown to reduce the risk of incident heart failure hospitalization in individuals with type 2 diabetes who have, or are at high risk of, cardiovascular disease. Most patients in these trials did not have heart failure at baseline and the effect of SGLT2 inhibitors on outcomes in individuals with established heart failure (with or without diabetes) is unknown. Design and methods: The Dapagliflozin And Prevention of Adverse‐outcomes in Heart Failure trial (DAPA‐HF) is an international, multicentre, parallel group, randomized, double‐blind, study in patients with chronic heart failure, evaluating the effect of dapagliflozin 10 mg, compared with placebo, given once daily, in addition to standard care, on the primary composite outcome of a worsening heart failure event (hospitalization or equivalent event, i.e. an urgent heart failure visit) or cardiovascular death. Patients with and without diabetes are eligible and must have a left ventricular ejection fraction ≤ 40%, a moderately elevated N‐terminal pro B‐type natriuretic peptide level, and an estimated glomerular filtration rate ≥ 30 mL/min/1.73 m2. The trial is event‐driven, with a target of 844 primary outcomes. Secondary outcomes include the composite of total heart failure hospitalizations (including repeat episodes), and cardiovascular death and patient‐reported outcomes. A total of 4744 patients have been randomized. Conclusions: DAPA‐HF will determine the efficacy and safety of the SGLT2 inhibitor dapagliflozin, added to conventional therapy, in a broad spectrum of patients with heart failure and reduced ejection fraction

    On hyperbolic fixed points in ultrametric dynamics

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    Let K be a complete ultrametric field. We give lower and upper bounds for the size of linearization discs for power series over K near hyperbolic fixed points. These estimates are maximal in the sense that there exist examples where these estimates give the exact size of the corresponding linearization disc. In particular, at repelling fixed points, the linearization disc is equal to the maximal disc on which the power series is injective.Comment: http://www.springerlink.com/content/?k=doi%3a%2810.1134%2fS2070046610030052%2

    Revealing hidden species distribution with pheromones: the case of Synanthedon vespiformis (Lepidoptera: Sesiidae) in Sweden

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    Synanthedon vespiformis L. (Lepidoptera: Sesiidae) is considered a rare insect in Sweden, discovered in 1860, with only a few observations recorded until a sex pheromone attractant became available recently. This study details a national survey conducted using pheromones as a sampling method for this species. Through pheromone trapping we captured 439 specimens in Southern Sweden at 77 sites, almost tripling the number of previously reported records for this species. The results suggest that S. vespiformis is truly a rare species with a genuinely scattered distribution, but can be locally abundant. Habitat analyses were conducted in order to test the relationship between habitat quality and the number of individuals caught. In Sweden, S. vespiformis is thought to be associated with oak hosts, but our attempts to predict its occurrence by the abundance of oaks yielded no significant relationships. We therefore suggest that sampling bias and limited knowledge on distribution may have led to the assumption that this species is primarily reliant on oaks in the northern part of its range, whereas it may in fact be polyphagous, similar to S. vespiformis found as an agricultural pest in Central and Southern Europe. We conclude that pheromones can massively enhance sampling potential for this and other rare lepidopteran species. Large-scale pheromone-based surveys provide a snapshot of true presences and absences across a considerable part of a species national distribution range, and thus for the first time provide a viable means of systematically assessing changes in distribution over time with high spatiotemporal resolution
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