Search Results (3)

Wheat growth is highly sensitive to temperature fluctuations, and with the intensification of global climate change, low-temperature stress has become more frequent during various growth stages of wheat, severely affecting its growth and reducing wheat yield. An experiment examined the effects of low-temperature (daytime 8:00–20:00/nighttime 20:00–next day 8:00: 16 °C/8 °C, 12 °C/4 °C, 8 °C/0 °C, and 4 °C/−4 °C) and exposure durations (1, 3, and 5 days) on winter wheat yield during the anthesis stage. Compared to exposure duration, temperature was the main factor affecting dry matter accumulation, distribution, and transport. Temperature had an average influence of 79.7%, 57.5%, 61.9%, and 79.0% on dry matter distribution in the stem-sheath, leaf, spike axis+glume, and grain, respectively. It also affected pre-anthesis translocation amount, the contribution of pre-anthesis translocation to grains, post-anthesis accumulation amount, and the contribution of post-anthesis accumulation to grains by 48.3%, 55.1%, 44.2%, and 48.2%, respectively. Conversely, exposure duration mainly influenced grain-filling parameters, with an average effect of 43.8%, 44.0%, 83.3%, and 43.8% on the maximum filling rate, average filling rate, filling rate in the fast-increasing period, and filling rate during the slow growth period, respectively. Low-temperature duration also significantly altered the fast-increasing period, slow growth period, and grain weight per spike by 79.9%, 79.9%, and 51.3%, respectively. Low-temperature stress alters the accumulation and distribution of dry matter in wheat, and the duration of exposure further affects the grain-filling process, ultimately resulting in a decrease in yield. Full article

Each year in March, adherents of the Bahá’í faith abstain from eating and drinking from sunrise to sunset for 19 days. Thus, Bahá’í fasting (BF) can be considered as a form of daytime dry fasting. We investigated whether BF decreased energy expenditure after a meal and whether it improved anthropometric measures and systemic and tissue-level metabolic parameters. This was a self-controlled cohort study with 11 healthy men. We measured anthropometric parameters, metabolic markers in venous blood and pre- and postprandial energy metabolism at systemic (indirect calorimetry) and tissue (adipose tissue and skeletal muscle microdialysis) level, both before and during BF. During BF, we found reduced body weight, body mass index, body fat and blood glucose. Postprandial increase in energy expenditure was lower and diet-induced thermogenesis tended to be lower as well. In adipose tissue, perfusion, glucose supply and lipolysis were increased. In skeletal muscle, tissue perfusion did not change. Glucose supply and lipolysis were decreased. Glucose oxidation was increased, indicating improved insulin sensitivity. BF may be a promising approach to losing weight and improving metabolism and health. However, outside the context of religiously motivated fasting, skipping a meal in the evening (dinner cancelling) might be recommended, as metabolism appeared to be reduced in the evening. Full article

The accurate prediction of wildfire behavior and spread is possible only when fire and atmosphere simulations are coupled. In this work, we present a mechanism that causes a small fire to intensify by altering the atmosphere. These alterations are caused by fire-related fluxes at the surface. The fire plume and fluxes increase the convective available potential energy (CAPE) and the chance of the development of a strong pyroconvection system. To study this possible mechanism, we used WRF-Fire to capture fire line propagation as the result of interactions between heat and moisture fluxes, pressure perturbations, wind shear development and dry air downdraft. The wind patterns and dynamics of the pyroconvection system are simulated for the Horse River wildfire at Fort McMurray, Canada. The results revealed that the updraft speed reached up to 12 m/s. The entrainment mixed the mid and upper-level dry air and lowered the atmospheric moisture. The mid-level and upper-level dew point temperature changed by 5–10 ${}^{\circ }$ C in a short period of time. The buoyant air strengthened the ascent as soon as the nocturnal inversion was eliminated by daytime heating. The 887 J/kg total increase of CAPE in less than 5 h and the high bulk Richardson number (BRN) of 93 were indicators of the growing pyro-cumulus cell. The presented simulation has not improved the original model or supported leading-edge numerical weather prediction (NWP) achievements, except for adapting WRF-Fire for Canadian biomass fuel. However, we were able to present a great deal of improvements in wildfire nowcasting and short-term forecasting to save lives and costs associated with wildfires. The simulation is sufficiently fast and efficient to be considered for a real-time operational model. While the project was designed and succeeded as an NWP application, we are still searching for a solution for the intractable problems associated with political borders and the current liable authorities for the further development of a new generation of national atmosphere–wildfire forecasting systems. Full article