5,219 research outputs found

    Chemigation with Micronized Sulfur Rapidly Reduces Soil pH in a New Planting of Northern Highbush Blueberry

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    Northern highbush blueberry (Vaccinium corymbosum L.) is adapted to acidic soil conditions and often grows poorly when soil pH is greater than 5.5. When soil pH is high, growers will usually mix prilled elemental sulfur (So) into the soil before planting (converted to sulfuric acid by soil bacteria) and, if needed, inject acid into the irrigation water after planting. These practices are effective but often expensive, time consuming, and, in the case of acid, potentially hazardous. Here, we examined the potential of applying micronized So by chemigation through a drip system as an alternative to reduce soil pH in a new planting of ‘Duke’ blueberry. The planting was located in western Oregon and established on raised beds mulched with sawdust in Oct. 2010. The So product was mixed with water and injected weekly for a period of ≈2 months before planting and again for period of ≈2 months in late summer of the second year after planting (to assess its value for reducing soil pH once the field was established), at a total rate of 0, 50, 100, and 150 kg·ha−1 So on both occasions. Each treatment was compared with the conventional practice of incorporating prilled So into the soil before planting (two applications of 750 kg·ha−1 So each in July and Oct. 2010). Within a month of the first application of So, chemigation reduced soil pH (0–10 cm depth) from an average of 6.6 with no So to 6.1 with 50 kg·ha−1 So and 5.8 with 100 or 150 kg·ha−1 So. However, the reductions in pH were short term, and by May of the following year (2011), soil pH averaged 6.7, 6.5, 6.2, and 6.1 with each increasing rate of So chemigation, respectively. Soil pH in the conventional treatment, in comparison, averaged 6.6 a month after the first application and 6.3 by the following May. In July 2012, soil pH ranged from an average of 6.4 with no So to 6.2 with 150 kg·ha−1 So and 5.5 with prilled So. Soil pH declined to as low as 5.9 following postplanting So chemigation and, at lower depths (10–30 cm), was similar between the treatment chemigated with 150 kg·ha−1 So and the conventional treatment. None of the treatments had any effect on winter pruning weight in year 1 or on yield, berry weight, or total dry weight of the plants in year 2. Concentration of P, K, Ca, Mg, S, and Mn in the leaves, on the other hand, was lower with So chemigation than with prilled So during the first year after planting, whereas concentration of N, P, and S in the leaves were lower with So chemigation during the second year. The findings indicate that So chemigation can be used to quickly reduce soil pH after planting and therefore may be a useful practice to correct high pH problems in established northern highbush blueberry fields; however, it was less effective and more time consuming than applying prilled So before plantin

    Macaque cardiac physiology is sensitive to the valence of passively viewed sensory stimuli.

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    Autonomic nervous system activity is an important component of affective experience. We demonstrate in the rhesus monkey that both the sympathetic and parasympathetic branches of the autonomic nervous system respond differentially to the affective valence of passively viewed video stimuli. We recorded cardiac impedance and an electrocardiogram while adult macaques watched a series of 300 30-second videos that varied in their affective content. We found that sympathetic activity (as measured by cardiac pre-ejection period) increased and parasympathetic activity (as measured by respiratory sinus arrhythmia) decreased as video content changes from positive to negative. These findings parallel the relationship between autonomic nervous system responsivity and valence of stimuli in humans. Given the relationship between human cardiac physiology and affective processing, these findings suggest that macaque cardiac physiology may be an index of affect in nonverbal animals

    Nitrogen Fertigation is Less Efficient but Safer than Granular Fertilizer Application in Newly-Planted Blueberry

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    Nitrogen fertilizer methods and rates were evaluated in a new field of highbush blueberry (Vaccinium corymbosum L. `Bluecrop"). Treatments included four application methods (split fertigation, continuous fertigation, and two non-fertigated controls) and four rates of N application (0, 50, 100, and 150 kg/ha of N). Fertigation treatments were irrigated by drip and injected with dissolved ammonium sulfate fertilizer; split fertigation was applied as a triple split from April to June while continuous fertigation was applied weekly from leaf emergence to 60 d prior to the end of the season. Non-fertigated controls were fertilized with granular ammonium sulfate and irrigated by drip or microsprays. Canopy cover, which indicates the relative size of young plants, was significantly affected by the rate of N fertilizer application during the first year after planting. The interaction between N application method and rate was also significant. In general, continuous fertigation produced the lowest canopy cover among treatments at 50 kg/ha of N and the highest canopy cover at 150 kg/ha. Apparently, the other methods required less N to produce their canopy but were less responsive than continuous fertigation to additional N fertilizer applications. In fact, up to half the plants died when they were fertilized at 150 kg/ha with granular fertilizer. This occurred whether plants were irrigated by drip or microspray. Alternatively, none of the plants died when they were fertigated continuously. Reduced growth and plant death was associated with high electrical conductivity in the soil solution (>3 dS/cm). The first year results indicate that fertigation is actually less efficient (i.e., less plant growth per unit of N applied) than granular fertilizer application but is also safer (i.e., less plant death) when high amounts of fertilizer is applied

    New Measurements of Venus Winds with Ground-Based Doppler Velocimetry at CFHT

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    operations with observations from the ground using various techniques and spectral domains (Lellouch and Witasse, 2008). We present an analysis of Venus Doppler winds at cloud tops based on observations made at the Canada France Hawaii 3.6-m telescope (CFHT) with the ESPaDOnS visible spectrograph. These observations consisted of high-resolution spectra of Fraunhofer lines in the visible range (0.37-1.05 μm) to measure the winds at cloud tops using the Doppler shift of solar radiation scattered by cloud top particles in the observer's direction (Widemann et al., 2007, 2008). The observations were made during 19-20 February 2011 and were coordinated with Visual Monitoring Camera (VMC) observations by Venus Express. The complete optical spectrum was collected over 40 spectral orders at each point with 2-5 seconds exposures, at a resolution of about 80000. The observations included various points of the dayside hemisphere at a phase angle of 67°, between +10° and -60° latitude, in steps of 10° , and from +70° to -12° longitude relative to sub-Earth meridian in steps of 12°. The Doppler shift measured in scattered solar light on Venus dayside results from two instantaneous motions: (1) a motion between the Sun and Venus upper cloud particles; (2) a motion between the observer and Venus clouds. The measured Doppler shift, which results from these two terms combined, varies with the planetocentric longitude and latitude and is minimum at meridian ΦN = ΦSun - ΦEarth where the two components subtract to each other for a pure zonal regime. Due to the need for maintaining a stable velocity reference during the course of acquisition using high resolution spectroscopy, we measure relative Doppler shifts to ΦN. The main purpose of our work is to provide variable wind measurements with respect to the background atmosphere, complementary to simultaneous measurements made with the VMC camera onboard the Venus Express. We will present first results from this work, comparing with previous results by the CFHT/ESPaDOnS and VLT-UVES spectrographs (Machado et al., 2012), with Galileo fly-by measurements and with VEx nominal mission observations (Peralta et al., 2007, Luz et al., 2011). Acknowledgements: The authors acknowledge support from FCT through projects PTDC/CTE-AST/110702/2009 and PEst-OE/FIS/UI2751/2011. PM and TW also acknowledge support from the Observatoire de Paris. Lellouch, E., and Witasse, O., A coordinated campaign of Venus ground-based observations and Venus Express measurements, Planetary and Space Science 56 (2008) 1317-1319. Luz, D., et al., Venus's polar vortex reveals precessing circulation, Science 332 (2011) 577-580. Machado, P., Luz, D. Widemann, T., Lellouch, E., Witasse, O, Characterizing the atmospheric dynamics of Venus from ground-based Doppler velocimetry, Icarus, submitted. Peralta J., R. Hueso, A. Sánchez-Lavega, A reanalysis of Venus winds at two cloud levels from Galileo SSI images, Icarus 190 (2007) 469-477. Widemann, T., Lellouch, E., Donati, J.-F., 2008, Venus Doppler winds at Cloud Tops Observed with ESPaDOnS at CFHT, Planetary and Space Science, 56, 1320-1334

    Mass Spectrometry-Based Proteomics Analysis Of Bioactive Proteins In EMD That Modulate Adhesion Of Gingival Fibroblast To Improve Bio-Integration Of Dental Implants

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    Titanium implants are used in dental practice to replace damaged or lost teeth. The implant needs to integrate with the surrounding gingiva to protect it against bacterial invasion that leads to implant loss. The biointegration is dependent on the implant surface that interacts with proteins from biological fluids to modulate tissues response. Tailoring the surface with specific proteins from the enamel matrix derivative (EMD) would be beneficial to improve the implant-gingiva interface since EMD can affect various cells including gingival fibroblasts. A surface-affinity approach using three different titanium surfaces and saliva was utilized as a model in combination with tandem mass spectrometry (MS/MS) to investigate protein binding specificity and the possibility of creating a surface-specific coating with identified bioactive proteins in EMD. Using this approach, we showed a low specificity for protein binding despite differences in surface characteristics. Due to the lack of specificity, EMD composition was investigated through the MudPIT methodology, which resulted in the analysis of 32 fraction. The proteome characterization through MS/MS identified 2000 proteins including novel proteins that are associated with biomineralization, wound healing, and biological adhesion. The further exposure of HGF to EMD fractions revealed two fractions (F23 and F24) that promoted significantly higher HGF adhesion than native EMD and other fractions. Overall, our results provide an in-depth insight into EMD composition showing its high complexity in protein content, including novel proteins that are related to EMD biological activity such as on adhesion of HGF

    Inclusive Intelligent Learning Management System Framework - Application of Data Science in Inclusive Education

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    Dissertation presented as the partial requirement for obtaining a Master's degree in Data Science and Advanced Analytics, specialization in Data ScienceBeing a disabled student the author faced higher education with a handicap which as experience studying during COVID 19 confinement periods matched the findings in recent research about the importance of digital accessibility through more e-learning intensive academic experiences. Narrative and systematic literature reviews enabled providing context in World Health Organization’s International Classification of Functioning, Disability and Health, legal and standards framework and information technology and communication state-of-the art. Assessing Portuguese higher education institutions’ web sites alerted to the fact that only outlying institutions implemented near perfect, accessibility-wise, websites. Therefore a gap was identified in how accessible the Portuguese higher education websites are, the needs of all students, including those with disabilities, and even the accessibility minimum legal requirements for digital products and the services provided by public or publicly funded organizations. Having identified a problem in society and exploring the scientific base of knowledge for context and state of the art was a first stage in the Design Science Research methodology, to which followed development and validation cycles of an Inclusive Intelligent Learning Management System Framework. The framework blends various Data Science study fields contributions with accessibility guidelines compliant interface design and content upload accessibility compliance assessment. Validation was provided by a focus group whose inputs were considered for the version presented in this dissertation. Not being the purpose of the research to deliver a complete implementation of the framework and lacking consistent data to put all the modules interacting with each other, the most relevant modules were tested with open data as proof of concept. The rigor cycle of DSR started with the inclusion of the previous thesis on Atlântica University Institute Scientific Repository and is to be completed with the publication of this thesis and the already started PhD’s findings in relevant journals and conferences

    EFFECT OF DIFFERENT STORAGE CONDITIONS ON NUTRITIONAL AND QUALITY PARAMETERS OF 'SWEETHEART' CHERRY.

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    Abstract The sweet cherry ‘Sweetheart’, although having a short shelf life, is highly appreciated by consumers due to its organoleptic characteristics. Different storage methods were tested to study the maintenance of quality during a period of 27 days: 1) cold (air at 1°C and 95% relative humidity) (CC), 2) cold and polypropylene film bags (1°C and 95% relative humidity) (MA) and 3) cold and controlled atmosphere (1°C, 95% RH, 10% CO2 and 8% O2) (CA). Quality parameters tested included external colour (L*, a*, b*), total soluble solids (TSS), and titratable acidity (TA). To evaluate nutritional quality anthocyanins, total antioxidant activity, and total phenolics were measured. Results allow us to say that phenolic compounds were relatively stable and similar during storage in CC and MA. Cherries stored under CA conditions presented lowest concentrations of phenolic compounds. Phenolic compounds, total anthocyanins and antioxidant activity were inversely correlated with values of colour coordinates. Considering all the evaluations done during this work it is unquestionable that fruits stored in controlled atmosphere conditions had significantly different quality

    Effects of Salinity Induced by Ammonium Sulfate Fertilizer on Root and Shoot Growth of Highbush Blueberry

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    Abstract Ammonium sulfate fertilizer is commonly used in highbush blueberry (Vaccinium corymbosum L.) but often causes salt damage, particularly in young plants, when high rates are applied. Three experiments were done to determine the sensitivity of ‘Bluecrop’ blueberry to ammonium sulfate and identify the salinity threshold at which plant growth was affected. In the first experiment, plants were grown in pots and fertigated two to three times per week with 0, 0.25, 0.75, and 1.5 g·L-1 ammonium sulfate solution. Electrical conductivity of the solutions (ECw) increased linearly with fertilizer rate and averaged 0.1, 0.5, 1.5, and 3.0 dS·m-1, respectively. Plants fertigated with 1.5 g·L-1 ammonium sulfate produced less leaves and roots and had a lower leaf to stem dry weight ratio than those fertilized with 0 or 0.25 g·L-1, which indicates that root and leaf growth in blueberry was sensitive to ECw > 1.5 dS·m-1. In the second experiment, plants in pots were fertilized with ammonium sulfate or urea at a frequency of three times per week, weekly, or every 28 days, using the same total amount of nitrogen (N) in each treatment over a 4-week period. In this case, plant growth was higher with ammonium sulfate than with urea but also higher, regardless of fertilizer source, when plants were fertilized more frequently. In the third experiment, plants were grown in the field with no N fertilizer or with ammonium sulfate or urea applied by weekly fertigations or by a triple-split application of granular fertilizer at a total rate of 133 kg·ha-1 N during the third year after planting. Yield in the plants was greater with fertigation or with granular urea than with granular ammonium sulfate, the latter of which resulted in ECw levels in the soil solution as high as 13 dS·m-1. In the field, fertilizer programs and practices such as fertigation that maintain ECw < 2 dS·m-1 are recommended for highbush blueberry
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