973 research outputs found

    Grape Irrigation

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    This fact sheet describes how to properly manage irrigation of grapes for the long-term health and productivity of your planting

    Critical Temperature for Sub-lethal Cold Injury of Strawberry Leaves

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    Freezing temperatures are a major limitation to strawberry production in temperate regions, and protected-cultivation strategies such as the use of tunnels and row covers are used to overcome this limitation. In order to optimize management under protected cultivation, it is necessary to understand the damage thresholds for strawberry plant tissues. The effects of freezing temperatures (−3, −5, and −7 °C) on leaf CO2 assimilation were evaluated for ‘Chandler’, ‘Seascape’ and ‘Jewel’ strawberry (Fragaria × ananassa). Growth chambers were used to expose plants to freezing temperatures under carefully defined conditions. Net assimilation was then measured on the cold-exposed leaves after the plants had been returned to 10 °C. Exposure to −3 °C did not significantly reduce CO2 assimilation when compared to plants maintained at 10 °C day/5 °C night. However, leaves exposed to −5 °C for one night had a net CO2assimilation rate that was 49% of the control. When leaves were first exposed to a conditioning night of −3 °C and then exposed to −5 °C, the net assimilation rate was 62% of the untreated control. Repeated exposure to −5 or −7 °C night temperatures resulted in a further decrease in net assimilation after each successive exposure. Leaves exposed to −7 °C for one night had a net assimilation rate of 6% of the control. Leaves exposed to −5 °C or −7 °C did not show any recovery over a 28-d monitoring period. There was no significant difference among cultivars in the sensitivity of leaves to cold temperatures. These results indicate that protected cultivation systems should be managed to maintain strawberry leaf temperatures above −5 °C in order to preserve full photosynthetic activity of existing leaves which would extend the growing season of the crop

    Adaptability of Tree Species as Windbreaks for Urban Farms in the U.S. Intermountain West

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    Windbreaks or shelterbelts are a management tool to protect crops from damaging horizontal wind flow, and may provide a useful buffer between farmland and urbanized areas by reducing pesticide drift, dust, and noise associated with farming activities. Plant selection for windbreaks in the Intermountain West can be difficult as high elevation coupled with extreme temperatures, high pH soils, and limited access to water are common. This study assessed eight tree species for suitability as a windbreak in the Intermountain West, with a particular focus on initial establishment and use at the urban–agriculture interface. Species were assessed for mortality, size, canopy density, insect and disease issues, and initial cost. Measurements of shadow characteristics were used as a novel approach to compare canopy density and porosity. Standard poplar (Populus x canadensis) and ‘Theves’ columnar poplar (Populus nigra ‘Afghanica’) were the most effective at rapid establishment, but species with more moderate growth rates, such as aspen, juniper, and hackberry, may provide lower long-term maintenance costs for the environmental conditions found in the Intermountain West

    Dose-Response Aligned Circuits in Signaling Systems

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    Cells use biological signal transduction pathways to respond to environmental stimuli and the behavior of many cell types depends on precise sensing and transmission of external information. A notable property of signal transduction that was characterized in the Saccharomyces cerevisiae yeast cell and many mammalian cells is the alignment of dose-response curves. It was found that the dose response of the receptor matches closely the dose responses of the downstream. This dose-response alignment (DoRA) renders equal sensitivities and concordant responses in different parts of signaling system and guarantees a faithful information transmission. The experimental observations raise interesting questions about the nature of the information transmission through DoRA signaling networks and design principles of signaling systems with this function. Here, we performed an exhaustive computational analysis on network architectures that underlie the DoRA function in simple regulatory networks composed of two and three enzymes. The minimal circuits capable of DoRA were examined with Michaelis-Menten kinetics. Several motifs that are essential for the dynamical function of DoRA were identified. Systematic analysis of the topology space of robust DoRA circuits revealed that, rather than fine-tuning the network's parameters, the function is primarily realized by enzymatic regulations on the controlled node that are constrained in limiting regions of saturation or linearity

    Child/Adolescent Anxiety Multimodal Study (CAMS): rationale, design, and methods

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    <p>Abstract</p> <p>Objective</p> <p>To present the design, methods, and rationale of the Child/Adolescent Anxiety Multimodal Study (CAMS), a recently completed federally-funded, multi-site, randomized placebo-controlled trial that examined the relative efficacy of cognitive-behavior therapy (CBT), sertraline (SRT), and their combination (COMB) against pill placebo (PBO) for the treatment of separation anxiety disorder (SAD), generalized anxiety disorder (GAD) and social phobia (SoP) in children and adolescents.</p> <p>Methods</p> <p>Following a brief review of the acute outcomes of the CAMS trial, as well as the psychosocial and pharmacologic treatment literature for pediatric anxiety disorders, the design and methods of the CAMS trial are described.</p> <p>Results</p> <p>CAMS was a six-year, six-site, randomized controlled trial. Four hundred eighty-eight (N = 488) children and adolescents (ages 7-17 years) with DSM-IV-TR diagnoses of SAD, GAD, or SoP were randomly assigned to one of four treatment conditions: CBT, SRT, COMB, or PBO. Assessments of anxiety symptoms, safety, and functional outcomes, as well as putative mediators and moderators of treatment response were completed in a multi-measure, multi-informant fashion. Manual-based therapies, trained clinicians and independent evaluators were used to ensure treatment and assessment fidelity. A multi-layered administrative structure with representation from all sites facilitated cross-site coordination of the entire trial, study protocols and quality assurance.</p> <p>Conclusions</p> <p>CAMS offers a model for clinical trials methods applicable to psychosocial and psychopharmacological comparative treatment trials by using state-of-the-art methods and rigorous cross-site quality controls. CAMS also provided a large-scale examination of the relative and combined efficacy and safety of the best evidenced-based psychosocial (CBT) and pharmacologic (SSRI) treatments to date for the most commonly occurring pediatric anxiety disorders. Primary and secondary results of CAMS will hold important implications for informing practice-relevant decisions regarding the initial treatment of youth with anxiety disorders.</p> <p>Trial registration</p> <p>ClinicalTrials.gov NCT00052078.</p

    Psychosocial risk factors for suicidality in children and adolescents

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    Suicidality in childhood and adolescence is of increasing concern. The aim of this paper was to review the published literature identifying key psychosocial risk factors for suicidality in the paediatric population. A systematic two-step search was carried out following the PRISMA statement guidelines, using the terms 'suicidality, suicide, and self-harm' combined with terms 'infant, child, adolescent' according to the US National Library of Medicine and the National Institutes of Health classification of ages. Forty-four studies were included in the qualitative synthesis. The review identified three main factors that appear to increase the risk of suicidality: psychological factors (depression, anxiety, previous suicide attempt, drug and alcohol use, and other comorbid psychiatric disorders); stressful life events (family problems and peer conflicts); and personality traits (such as neuroticism and impulsivity). The evidence highlights the complexity of suicidality and points towards an interaction of factors contributing to suicidal behaviour. More information is needed to understand the complex relationship between risk factors for suicidality. Prospective studies with adequate sample sizes are needed to investigate these multiple variables of risk concurrently and over time

    A General Definition and Nomenclature for Alternative Splicing Events

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    Understanding the molecular mechanisms responsible for the regulation of the transcriptome present in eukaryotic cells is one of the most challenging tasks in the postgenomic era. In this regard, alternative splicing (AS) is a key phenomenon contributing to the production of different mature transcripts from the same primary RNA sequence. As a plethora of different transcript forms is available in databases, a first step to uncover the biology that drives AS is to identify the different types of reflected splicing variation. In this work, we present a general definition of the AS event along with a notation system that involves the relative positions of the splice sites. This nomenclature univocally and dynamically assigns a specific “AS code” to every possible pattern of splicing variation. On the basis of this definition and the corresponding codes, we have developed a computational tool (AStalavista) that automatically characterizes the complete landscape of AS events in a given transcript annotation of a genome, thus providing a platform to investigate the transcriptome diversity across genes, chromosomes, and species. Our analysis reveals that a substantial part—in human more than a quarter—of the observed splicing variations are ignored in common classification pipelines. We have used AStalavista to investigate and to compare the AS landscape of different reference annotation sets in human and in other metazoan species and found that proportions of AS events change substantially depending on the annotation protocol, species-specific attributes, and coding constraints acting on the transcripts. The AStalavista system therefore provides a general framework to conduct specific studies investigating the occurrence, impact, and regulation of AS

    Population genetic structure of Streptococcus pneumoniae in Kilifi, Kenya, prior to the introduction of pneumococcal conjugate vaccine.

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    BACKGROUND: The 10-valent pneumococcal conjugate vaccine (PCV10) was introduced in Kenya in 2011. Introduction of any PCV will perturb the existing pneumococcal population structure, thus the aim was to genotype pneumococci collected in Kilifi before PCV10. METHODS AND FINDINGS: Using multilocus sequence typing (MLST), we genotyped >1100 invasive and carriage pneumococci from children, the largest collection genotyped from a single resource-poor country and reported to date. Serotype 1 was the most common serotype causing invasive disease and was rarely detected in carriage; all serotype 1 isolates were members of clonal complex (CC) 217. There were temporal fluctuations in the major circulating sequence types (STs); and although 1-3 major serotype 1, 14 or 23F STs co-circulated annually, the two major serotype 5 STs mainly circulated independently. Major STs/CCs also included isolates of serotypes 3, 12F, 18C and 19A and each shared ≤ 2 MLST alleles with STs that circulate widely elsewhere. Major CCs associated with non-PCV10 serotypes were predominantly represented by carriage isolates, although serotype 19A and 12F CCs were largely invasive and a serotype 10A CC was equally represented by invasive and carriage isolates. CONCLUSIONS: Understanding the pre-PCV10 population genetic structure in Kilifi will allow for the detection of changes in prevalence of the circulating genotypes and evidence for capsular switching post-vaccine implementation

    Author Correction: The FLUXNET2015 dataset and the ONEFlux processing pipeline for eddy covariance data

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