2,485 research outputs found
Fruit quality in strawberry (Fragaria x ananassa Duch. cv. Korona) at three times during the season and with two fertilizer strategies
Effects on fruit quality of preplant fertilization and fertigation in strawberry were studied in a field experiment established August 2003 in South East Norway. Half the field was fertilized at planting and fertigated with a low nutrient rate from spring 2004 (T1), while the second half was unfertilized at planting but fertigated with a relatively high nutrient rate from spring 2004 (T2). Berries were harvested three times per week during the first harvesting year. Samples of berries from early season, mid season and late season were analysed for soluble solids, pH, titratable acidity, colour, vitamin C, antioxidant activity (FRAP) and mineral concentration. The results were correlated to leaf mineral concentration in dry matter. T1 gave larger and darker berries compared to T2. The other quality parameters and mineral content in strawberry fruits were not significantly influenced by the two fertilizer strategies. Soluble solids, pH, titratable acidity and colour varied significantly through the season, while vitamin C and antioxidant activity (FRAP) was unaffected by fertilizer treatment, berry size and time of season. The results gave a general view of the quality parameters in the strawberry cultivar âKoronaâ
Antioxidant activity in commonly grown and consumed vegetables: a screening survey
A diet rich in fruits and vegetables is associated with a reduced risk of developing cardiovascular diseases and certain types of cancer. This positive effect is related to bioactive phytochemicals found in plants.The vegetables were grown in the field or in greenhouses at the Norwegian University of Life Sciences (59Âș40âN) during the years 2000-2002. The vegetables were harvested at commercial maturity and analysed for dry matter and antioxidant activity assessed by the FRAP (Ferric Reducing Ability of Plasma) assay. There was a large variation in antioxidant activity both between and within different species. The highest antioxidant activity was observed in kale, red cultivars of cabbage and table beet. The lowest antioxidant activity was observed in lettuce, cucumber, carrots and tomato. The vegetables possessing a red colour showed higher antioxidant activity with the exception of carrots and tomatoes
MyoDâ/â Satellite Cells in Single-Fiber Culture Are Differentiation Defective and MRF4 Deficient
AbstractMyoD-deficient mice are without obvious deleterious muscle phenotype during embryogenesis and fetal development, and adults in the laboratory have grossly normal skeletal muscle and life span. However, a previous study showed that in the context of muscle degeneration on a mdx (dystrophin null) genetic background, animals lacking MyoD have a greatly intensified disease phenotype leading to lethality not otherwise seen in mdx mice. Here we have examined MyoDâ/â adult muscle fibers and their associated satellite cells in single myofiber cultures and describe major phenotypic differences found at the tissue, cellular, and molecular levels. The steady-state number of satellite cells on freshly isolated MyoDâ/â fibers was elevated and abnormal branched fiber morphologies were observed, the latter suggesting chronic muscle regeneration in vivo. Single-cell RNA coexpression analyses were performed for c-met, m-cadherin, and the four myogenic regulatory factors (MRFs.) Most mutant satellite cells entered the cell cycle and upregulated expression of myf5, both characteristic early steps in satellite cell maturation. However, they later failed to normally upregulate MRF4, displayed a major deficit in m-cadherin expression, and showed a significant diminution in myogenin-positive status compared with wildtype. MyoDâ/â satellite cells formed unusual aggregate structures, failed to fuse efficiently, and showed greater than 90% reduction in differentiation efficiency relative to wildtype. A further survey of RNAs encoding regulators of growth and differentiation, cell cycle progression, and cell signaling revealed similar or identical expression profiles for most genes as well as several noteworthy differences. Among these, GDF8 and Msx1 were identified as potentially important regulators of the quiescent state whose expression profile differs between mutant and wildtype. Considered together, these data suggest that activated MyoDâ/â satellite cells assume a phenotype that resembles in some ways a developmentally âstalledâ cell compared to wildtype. However, the MyoDâ/â cells are not merely developmentally immature, as they also display novel molecular and cellular characteristics that differ from any observed in wild-type muscle precursor counterparts of any stage
An approach towards rapid optical measurements of antioxidant activity in blueberry cultivars
Blueberries are well known for their high antioxidant levels. Compared to bilberries (V. myrtillus) with higher antioxidant activity and more intensive blue colour throughout the whole berry, highbush blueberries have the blue pigments concentrated in the skin. Highbush blueberry skin is found to contain a very high content of phenolic compounds. To measure the total antioxidant activity in blueberries, several methods, mostly destructive, including the FRAP assay, have been used. This work is an initial approach towards a simple and rapid method, combining optical and antioxidant activity measurements. Highbush blueberry (V. corymbosum) cultivars âBluecropâ, âHardyblueâ, âPatriotâ, and lowbush cultivars âPutteâ (a hybrid originated from V. angustifolium) and âAronâ (V. corymbosum x V. uliginosum) were grown at the Norwegian University of Life Sciences (59Âș 40âN). Berries were harvested at commercial blue-ripe stage of maturity. Fresh berries were cut horizontally and placed on a scanner in order to examine berry size and skin thickness. Berries were weighed, and analysed for antioxidant activity using the FRAP (Ferric Reducing Ability of Plasma) assay. The FRAP assay is a non-specific method based on absorption changes following a reduction of a ferric- to a ferrous-complex in the presence of antioxidants.Own previous results have shown that antioxidant activity and berry weight varied between cultivars (REMBERG et al., 2003). Small berries had higher antioxidant activity compared to larger berries. In this follow-up project, skin thickness and berry diameter were measured by using an image- processing program. Berry and skin cross-section areas were correlated with the antioxidant activity
Alternative global Cretaceous paleogeography
Plate tectonic reconstructions for the Cretaceous have assumed that the major
continental blocksâEurasia, Greenland, North America, South America, Africa, India,
Australia, and Antarcticaâhad separated from one another by the end of the Early
Cretaceous, and that deep ocean passages connected the Pacific, Tethyan, Atlantic, and
Indian Ocean basins. North America, Eurasia, and Africa were crossed by shallow
meridional seaways. This classic view of Cretaceous paleogeography may be incorrect.
The revised view of the Early Cretaceous is one of three large continental blocksâ
North AmericaâEurasia, South AmericaâAntarctica-India-Madagascar-Australia;
and Africaâwith large contiguous land areas surrounded by shallow epicontinental
seas. There was a large open Pacific basin, a wide eastern Tethys, and a circum-
African Seaway extending from the western Tethys (âMediterraneanâ) region
through the North and South Atlantic into the juvenile Indian Ocean between
Madagascar-India and Africa. During the Early Cretaceous the deep passage from
the Central Atlantic to the Pacific was blocked by blocks of northern Central America
and by the Caribbean plate. There were no deep-water passages to the Arctic. Until
the Late Cretaceous the Atlantic-Indian Ocean complex was a long, narrow, sinuous
ocean basin extending off the Tethys and around Africa.
Deep passages connecting the western Tethys with the Central Atlantic, the
Central Atlantic with the Pacific, and the South Atlantic with the developing Indian
Ocean appeared in the Late Cretaceous. There were many island land areas surrounded
by shallow epicontinental seas at high sea-level stands
Probing Patchy Reionization with the Void Probability Function of Lyman- Emitters
We probe what constraints for the global ionized hydrogen fraction the Void
Probability Function (VPF) clustering can give for the Lyman-Alpha Galaxies in
the Epoch of Reionization (LAGER) narrowband survey as a function of area.
Neutral hydrogen acts like a fog for Lyman-alpha emission, and measuring the
drop in the luminosity function of Lyman- emitters (LAEs) has been used
to constrain the ionization fraction in narrowband surveys. However, the
clustering of LAEs is independent from the luminosity function's inherent
evolution, and can offer additional constraints for reionization under
different models. The VPF measures how likely a given circle is to be empty. It
is a volume-averaged clustering statistic that traces the behavior of higher
order correlations, and its simplicity offers helpful frameworks for planning
surveys.
Using the \citet{Jensen2014} simulations of LAEs within various amount of
ionized intergalactic medium, we predict the behavior of the VPF in one
(301x150.5x30 Mpc), four (5.44 Mpc), or eight (1.1 Mpc) fields of LAGER imaging. We examine the VPF at 5 and 13
arcminutes, corresponding to the minimum scale implied by the LAE density and
the separation of the 2D VPF from random, and the maximum scale from the
8-field 15.5 deg LAGER area. We find that even a single DECam field of
LAGER (2-3 deg) could discriminate between mostly neutral vs. ionized.
Additionally, we find four fields allows the distinction between 30, 50, and 95
percent ionized; and that eight fields could even distinguish between 30, 50,
73, and 95 percent ionized.Comment: 14 pages, 5 figure
Use of near infrared reflectance spectroscopy to predict nitrogen uptake by winter wheat within fields with high variability in organic matter
In this study, the ability to predict N-uptake in winter wheat crops using NIR-spectroscopy on soil samples was evaluated. Soil samples were taken in unfertilized plots in one winter wheat field during three years (1997-1999) and in another winter wheat field nearby in one year (2000). Soil samples were analyzed for organic C content and their NIR-spectra. N-uptake was measured as total N-content in aboveground plant materials at harvest. Models calibrated to predict N-uptake were internally cross validated and validated across years and across fields. Cross-validated calibrations predicted N-uptake with an average error of 12.1 to 15.4 kg N ha-1. The standard deviation divided by this error (RPD) ranged between 1.9 and 2.5. In comparison, the corresponding calibrations based on organic C alone had an error from 11.7 to 28.2 kg N ha-1 and RPDs from 1.3 to 2.5. In three of four annual calibrations within a field, the NIR-based calibrations worked better than the organic C based calibrations. The prediction of N-uptake across years, but within a field, worked slightly better with an organic C based calibration than with a NIR based one, RPD = 1.9 and 1.7 respectively. Across fields, the corresponding difference was large in favour of the NIR-calibration, RPD = 2.5 for the NIR-calibration and 1.5 for the organic C calibration. It was concluded that NIR-spectroscopy integrates information about organic C with other relevant soil components and therefore has a good potential to predict complex functions of soils such as N-mineralization. A relatively good agreement of spectral relationships to parameters related to the N-mineralization of datasets across the world suggests that more general models can be calibrated
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