81 research outputs found
Recommended from our members
Evaluation of ECMWF medium-range ensemble forecasts of precipitation for river basins
Providing probabilistic forecasts using Ensemble Prediction Systems has become increasingly popular in both the meteorological and hydrological communities. Compared to conventional deterministic forecasts, probabilistic forecasts may provide more reliable forecasts of a few hours to a number of days ahead, and hence are regarded as better tools for taking uncertainties into consideration and hedging against weather risks. It is essential to evaluate performance of raw ensemble forecasts and their potential values in forecasting extreme hydro-meteorological events. This study evaluates ECMWF's medium-range ensemble forecasts of precipitation over the period 1 January 2008 to 30 September 2012 on a selected midlatitude large-scale river basin, the Huai river basin (ca. 270 000 km2) in central-east China. The evaluation unit is sub-basin in order to consider forecast performance in a hydrologically relevant way. The study finds that forecast performance varies with sub-basin properties, between flooding and non-flooding seasons, and with the forecast properties of aggregated time steps and lead times. Although the study does not evaluate any hydrological applications of the ensemble precipitation forecasts, its results have direct implications in hydrological forecasts should these ensemble precipitation forecasts be employed in hydrology
Physicochemical and nutritional properties of rice as affected by parboiling steaming time at atmospheric pressure and variety
To elucidate the effect of different parboiling steaming time on the physicochemical and nutritional quality of rice, four varieties, NERICA1, NERICA7, IR841, and WITA4, were soaked at the same initial temperature (85°C) and steamed for 5, 15, 25, 35, and 45 min. NERICA7 steamed for 25 min recorded the highest head rice yield (71.9%). Nonparboiled IR841 recorded the shortest cooking time (17.0 min), while NERICA1 steamed for 35 min recorded the longest cooking time (26.1 min). NERICA1 steamed for 45 min was the hardest (63.2 N), while nonparboiled IR841 was the softest (28.7 N). NERICA7 recorded higher peak and final viscosities across all steaming times compared to the other varieties. NERICA7 steamed for 35 and 45 min recorded the lowest total starch (77.3%) and the highest protein (13.2%) content, respectively. NERICA7 steamed for 25 and 45 min recorded the highest phosphorus (0.166%), magnesium (572 mg/kg), and potassium (2290 mg/kg) content, respectively. We conclude that, depending on desired physicochemical and nutritional properties, specific varieties and steaming times can be selected to achieve those outcomes
Appropriate parboiling steaming time at atmospheric pressure and variety to produce rice with weak digestive properties
Consumers with diabetes mellitus have shown interest in products with low postprandial glucose. To produce rice for this group of consumers, the effect of parboiling steaming time (0, 5, 15, 25, 35, and 45 min) and variety (NERICA1, NERICA7, WITA4, and IR841) on resistant, damaged starch fractions and glycemic response in rats was investigated. Resistant and damaged starch fractions were influenced by variety and steaming time but this was not the case for glycemic index. Nonparboiled NERICA7 and NERICA7 steamed for 25 min recorded the highest (10.07%) and lowest (2.49%) resistant starch fraction, respectively. Resistant starch correlated negatively with protein and sodium and positively with lipids. Damaged starch was high for WITA4 steamed for 45 min (26.80%) and low for nonparboiled NERICA1 (6.59%). Damaged starch correlated positively with lipid content and negatively with ash and total starch content. NERICA7 steamed for 35 min recorded the lowest postprandial glucose level 30 min after feeding (0.16 g/L), while WITA4 steamed for 15, 25, and 35 min and nonparboiled NERICA7 recorded higher levels (0.76, 0.91, 0.84, and 0.76 g/L, respectively). NERICA7 steamed for 35 min recorded both low glycemic and weak digestive properties because the glycemic index was lowest 120 min and increased steadily up to 180 min after feeding. We conclude that the digestive properties of rice depend both on the intrinsic properties of the variety and the parboiling steaming time
Optimisation de la fermentation en milieu semi-solide pour la production dâablo, pain cuit a la vapeur dâAfrique de lâouest
Objectif : Evaluer trois Ă©quipements pour la fermentation de la pĂąte destinĂ©e Ă prĂ©parer lâablo (pĂąte cuite Ă Â la vapeur) puis, lâinfluence de la tempĂ©rature, de la durĂ©e de fermentation et du taux de levure ajoutĂ©e Ă la pĂąte.MĂ©thodologie et rĂ©sultats : La pĂąte semi-solide a Ă©tĂ© fermentĂ©e durant quatre heures Ă tempĂ©rature ambiante (26-27 °C) dans du bac en verre, glaciĂšre et bassine en aluminium (TĂ©moin). En outre, lâeffet de la tempĂ©rature, de la durĂ©e de fermentation et du taux de levure a Ă©tĂ© Ă©valuĂ© Ă travers un dispositif factoriel complet dont les niveaux bas et hauts des facteurs rangeaient entre 2 et 6 heures, 22 et 30 °C et 1 et 3 g/Kg de farine. La pousse, le pH, lâaciditĂ© titrable et la charge en levures/moisissures ont Ă©tĂ© dĂ©terminĂ©s. A lâexception de la quantitĂ© de mousse produite et de la matiĂšre sĂšche, aucun effet significatif (P>0,05) du matĂ©riel de fermentation nâa Ă©tĂ© mis en Ă©vidence sur les paramĂštres mesurĂ©s. Le taux de levure, la tempĂ©rature et la durĂ©e de fermentation avaient une influence positive significative (P<0,05) sur la quantitĂ©Â de mousse produite.Conclusion et application : Le dispositif en verre, suivi de la glaciĂšre, avaient gĂ©nĂ©rĂ© la plus grande quantitĂ©Â de mousse, probablement Ă cause dâune relative hermĂ©ticitĂ© ou de la forme gĂ©omĂ©trique rĂ©guliĂšre des deux dispositifs. Au rendement en pĂąte voisin de 180, la fermentation dans les conditions optimales validĂ©es exigeait 30 °C, 3 g de levure par Kg de farine de riz et 4 h de conditionnement ; ce qui donne une pĂąte fermentĂ©e possĂ©dant un pH compris entre 4,42 et 4,64, une teneur de matiĂšre sĂšche variant entre 29,99 et 38,79% et la variation de hauteur de la mousse comprise entre 4,85 et 5,62 cm. Il serait intĂ©ressant de tester ces conditions optima de fermentation sur autres matiĂšres premiĂšres (maĂŻs, mĂ©lange riz-maĂŻs) intervenant dans la production dâablo.Mots clĂ©s : Ablo, levures, optimisation, fermentation, rizOptimization of semi-solid state fermentation for processing ablo, a wet steamed bread from West AfricaObjective: To test three equipments for the fermentation of rice semi-solid dough to produce ablo (a steamy and foamy bread) and then, to investigate the effect of fermentation temperature and duration and the rate of yeast on some critical parametersMethodology and results: The semi-solid dough was fermented for four hours in glass box, icebox and aluminum bowls (Control) at ambient temperature (26-27 °C). In addition, the effect of fermentation temperature and duration and the rate of yeast were investigated using full factorial design, with values ranging between 2 and 6 hours, 22 and 30 °C and 1 and 3 g/Kg flour. The pH, titrable acidity, the dry matter content and the quantity of moss/foam were determined as well as the yeast and fungi counts. Except for the moss produced and the dry matter content, no significant effect was evidenced on all other parameters measured as far as the equipment is considered. Significant and positive effects of temperature, duration and the rate of yeast (P<0.05) were observed on the quantity of moss producedConclusion and application: The glass box, followed by icebox were the best fermenting equipments of the dough, giving great amount of moss produced, probably due the airtight or the regular form of both equipments. At the dough yield of 180, the optimal values of these factors for upgrading fermentation of the rice dough included 30 °C, 3 g of yeast per Kg of flour and 4 hours of resting. These conditions was validated and lead to the fermented dough with pH ranging between 4.42 and 4.64, dry matter between 29.99 et 38.79% and moss height varying from 4.85 to 5.62 cm. In further work, it will be appreciated to test these optima conditions on maize or the mix rice-maize flour since they are raw materials for ablo productionKeywords: Yeast, optimization, fermentation, Abl
A high-resolution view of the jets in 3C 465
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. https://doi.org/10.1093/mnras/staa147.We present new high-resolution and high-sensitivity studies of the jets in the WAT source 3C 465, using deep transverse-resolved radio observations from e-MERLIN, and with complementary observations from the VLA. We derive a lower limit = (/) 0.5 for the jet speed, and an upper limit 61 for the jet angle to the line of sight. The jet spectral index (, defined in the sense ) is fairly constant ( = 0.7), and spectral flattening within 4.4 kpc of the core coincides with bright knots and is consistent with the site of X-ray particle acceleration at the base of the radio jet found in previous studies. There is little difference between the spectra of the two hotspot components, plausibly indicating that electron populations of the same properties are injected there. The NW and SE plumes are approximately homologous structures, with variations in mass injection and propagation in external pressure and density gradients in the two regions plausibly accounting for the slightly steeper spectrum in the NW plume, = 1.43 compared with the SE plume, = 1.38. Our synchrotron lifetime model supports plausible reacceleration of particles within the plume materials. Overall, our results show that the first-order Fermi process at mildly relativistic and non-relativistic shocks is the most likely acceleration mechanism at play in 3C 465 and distinguish differences between the acceleration at 0.5 and $Peer reviewe
Macromolecular Traits in the African Rice Oryza glaberrima and in Glaberrima/Sativa Crosses, and Their Relevance to Processing
Molecular properties of proteins and starch were investigated in 2 accessions of Oryza glaberrima and Oryza sativa, and in one NERICA cross between the 2 species, to assess traits that could be relevant to transformation into specific foods. Protein nature and organization in O. glaberrima were different from those in O. sativa and in NERICA. Despite the similar cysteine content in all samples, thiol accessibility in O. glaberrima proteins was higher than in NERICA or in O. sativa. Inter-protein disulphide bonds were important for the formation of protein aggregates in O. glaberrima, whereas non-covalent protein-protein interactions were relevant in NERICA and O. sativa. DSC and NMR studies indicated only minor differences in the structure of starch in these species, as also made evident by their microstructural features. Nevertheless, starch gelatinization in O. glaberrima was very different from what was observed in O. sativa and NERICA. The content of soluble species in gelatinized starch from the various species in the presence/absence of treatments with specific enzymes indicated that release of small starch breakdown products was lowest in O. glaberrima, in particular from the amylopectin component. These findings may explain the low glycemic index of O. glaberrima, and provide a rationale for extending the use of O. glaberrima in the production of specific rice-based products, thus improving the economic value and the market appeal of African crops
Radio jets in NGC 1068 with e-MERLIN and VLA: structure and morphology
We present new high-sensitivity e-MERLIN and VLA radio images of the
prototypical Seyfert 2 galaxy NGC 1068 at 5, 10 and 21 GHz. We image the radio
jet, from the compact components NE, C, S1 and S2 to the faint double-lobed jet
structure of the NE and SW jet lobes. Furthermore, we map the jet between by
combining e-MERLIN and VLA data for the first time. Components NE, C and S2
have steep spectra indicative of optically-thin non-thermal emission domination
between 5 and 21 GHz. Component S1, which is where the AGN resides, has a flat
radio spectrum. We report a new component, S2a, a part of the southern jet. We
compare these new data with the MERLIN and VLA data observed in 1983, 1992 and
1995 and report a flux decrease by a factor of 2 in component C, suggesting
variability of this jet component. With the high angular resolution e-MERLIN
maps, we detect the bow shocks in the NE jet lobe that coincide with the
molecular gas outflows observed with ALMA. The NE jet lobe has enough radio
power considered to be responsible for driving out the dense molecular gas
observed with ALMA around the same region
Risks associated with global warming of 1.5 to 4 °C above pre-industrial levels in human and natural systems in six countries
The Topical Collection âAccrual of Climate Change Risk in Six Vulnerable Countriesâ provides a harmonised assessment of risks to human and natural systems due to global warming of 1.5â4 °C in six countries (China, Brazil, Egypt, Ethiopia, Ghana, and India) using a consistent set of climate change and socioeconomic scenarios. It compares risks in 2100 if warming has reached 3 °C, broadly corresponding to current global greenhouse gas emission reduction policies, including countriesâ National Determined Contributions, rather than the Paris Agreement goal of limiting warming to âwell belowâ 2 °C and âpursuing effortsâ to limit to 1.5 °C. Global population is assumed either constant at year 2000 levels or to increase to 9.2 billion by 2100. In either case, greater warming is projected to lead, in all six countries, to greater exposure of land and people to drought and fluvial flood hazard, greater declines in biodiversity, and greater reductions in the yield of maize and wheat. Limiting global warming to 1.5 °C, compared with ~ 3 °C, is projected to deliver large benefits for all six countries, including reduced economic damages due to fluvial flooding. The greatest projected benefits are the avoidance of a large increase in exposure of agricultural land to severe drought, which is 61%, 43%, 18%, and 21% lower in Ethiopia, China, Ghana, and India at 1.5 °C than at 3 °C, whilst avoided increases in human exposure to severe drought are 20â80% lower at 1.5 °C than 3 °C across the six countries. Climate refugia for plants are largely preserved at 1.5 °C warming in Ghana, China, and Ethiopia, but refugia shrink in areal extent by a factor of 2, 3, 3, 4, and 10 in Ghana, China, India, Ethiopia, and Brazil, respectively, if warming reaches 3 °C. Economic damages associated with sea-level rise are projected to increase in coastal nations, but more slowly if warming were limited to 1.5 °C. Actual benefits on the ground will also depend on national and local contexts and the extent of future investment in adaptation
Depletion of Trypanosome CTR9 Leads to Gene Expression Defects
The Paf complex of Opisthokonts and plants contains at least five subunits: Paf1, Cdc73, Rtf1, Ctr9, and Leo1. Mutations in, or loss of Paf complex subunits have been shown to cause defects in histone modification, mRNA polyadenylation, and transcription by RNA polymerase I and RNA polymerase II. We here investigated trypanosome CTR9, which is essential for trypanosome survival. The results of tandem affinity purification suggested that trypanosome CTR9 associates with homologues of Leo1 and Cdc73; genes encoding homologues of Rtf1 and Paf1 were not found. RNAi targeting CTR9 resulted in at least ten-fold decreases in 131 essential mRNAs: they included several that are required for gene expression and its control, such as those encoding subunits of RNA polymerases, exoribonucleases that target mRNA, RNA helicases and RNA-binding proteins. Simultaneously, some genes from regions subject to chromatin silencing were derepressed, possibly as a secondary effect of the loss of two proteins that are required for silencing, ISWI and NLP1
- âŠ