Pollutant dispersion in a developing valley cold-air pool

Pollutants are trapped and accumulate within cold-air pools, thereby affecting air quality. A numerical model is used to quantify the role of cold-air-pooling processes in the dispersion of air pollution in a developing cold-air pool within an alpine valley under decoupled stable conditions. Results indicate that the negatively buoyant downslope flows transport and mix pollutants into the valley to depths that depend on the temperature deficit of the flow and the ambient temperature structure inside the valley. Along the slopes, pollutants are generally entrained above the cold-air pool and detrained within the cold-air pool, largely above the ground-based inversion layer. The ability of the cold-air pool to dilute pollutants is quantified. The analysis shows that the downslope flows fill the valley with air from above, which is then largely trapped within the cold-air pool, and that dilution depends on where the pollutants are emitted with respect to the positions of the top of the ground-based inversion layer and cold-air pool, and on the slope wind speeds. Over the lower part of the slopes, the cold-air-pool-averaged concentrations are proportional to the slope wind speeds where the pollutants are emitted, and diminish as the cold-air pool deepens. Pollutants emitted within the ground-based inversion layer are largely trapped there. Pollutants emitted farther up the slopes detrain within the cold-air pool above the ground-based inversion layer, although some fraction, increasing with distance from the top of the slopes, penetrates into the ground-based inversion layer.Peer reviewe

Well-being interventions in U.S. colleges: a scoping review from a positive higher education perspective

In response to growing concerns about student mental health, this scoping review synthesizes 40 peer-reviewed empirical studies published between 2009 and 2024 on well-being interventions for undergraduate students in U.S. higher education, examined through the emerging lens of Positive Higher Education. Drawing from diverse methodologies and interventions—including mindfulness, cognitive-behavioral therapy, psychoeducation, and positive psychology strategies—the review examines how well-being is defined, implemented, and assessed across curricular and co-curricular contexts. While many interventions demonstrated positive outcomes, particularly in reducing stress and enhancing psychological well-being, the field remains limited by conceptual ambiguity, inconsistent theoretical frameworks, and insufficient attention to long-term institutionalization and sustainability. Most studies lacked a clearly articulated definition of well-being, and relatively few were embedded in academic curricula. This review underscores the need for a coordinated, theory-informed approach to integrating well-being as a core educational outcome, aligned with the values of liberal arts education. It concludes with a call to develop a Positive Higher Education Implementation Toolkit to guide institutions in embedding well-being into policy, pedagogy, and practice

Crinine-type alkaloids from Hippeastrum aulicum and H. calyptratum

An ongoing search for alkaloids in the Amaryllidaceae species using GC MS resulted in the identification of two crinine-type alkaloids, aulicine (1) and 3-O-methyl-epimacowine, (2) from the indigenous Brazilian species Hippeastrum aulicum and Hippeastrum calyptratum, respectively. In addition, two alkaloids, 11-oxohaemanthamine (3) and 7-methoxy-O-methyllycorenine (4) were both isolated from H. aulicum. Furthermore, we provide here complete NMR spectroscopic data for the homolycorine analogues nerinine (5) and albomaculine (6). The absolute stereochemistry of the 5,10b-ethano bridge in the crinine variants was determined by circular dichroism and X-ray crystallographic analysis, thus presenting the first direct evidence for the presence of crinine-type alkaloids in the genus Hippeastrum

Improved efficiency of soil solarization for growth and yield of greenhouse tomatoes

Soil solarization is a pre-planting treatment not based on chemicals, used in hot climates to control weeds and soil-borne pathogens. Its effectiveness has been widely demonstrated, for example, in the USA, Spain, Portugal, Egypt, Italy, Mexico, India and Iraq. However, an improvement in efficacy is needed before it can be widely adapted as a commercial practice. Supplementation of the soil with organic matter prior to solarization has been proposed as a management option, but its effectiveness has yet to be confirmed by any systematic study. Therefore, here we carried out a set of experiments in southern Italy over two seasons to study the effect of four levels of organic supplementation of 0, 0.35, 0.70 and 1.05 kg m−2 prior to solarization. Soil temperature and its chemical properties, as well as plant vegetation growth and fruit production were monitored for tomato plants grown under commercial greenhouse conditions. Organic supplementation increased the maximum soil temperature achieved through solarization by 3.9 °C to 4.7 °C. At 5 cm below the soil surface, a temperature of over 52 °C prevailed for 22 to 23 days when 0.70 kg m−2 organic supplement was incorporated, and for 14 to 13 days in the presence of 0.35 kg m−2 supplement, but this temperature was attained only for one day in the absence of any supplement. Organic supplementation significantly increased the soil concentration of ${\rm NO}_3^{-}-{\rm N}$, exchangeable K2O, Ca2+ and Mg2+ and electrical conductivity. Increased available P2O5 and total N at the end of the crop cycle were also associated with supplementation of solarized soil. Plant vegetative growth was improved by supplementation, with crop plant stem diameter enhanced by up to 18%, above-ground vegetative fresh and dry weight by up to, respectively, 53 and 44%, and the number of leaves per plant by up to 16%. As the supplementation rate was raised from 0 to 0.70 kg m−2, fruit yield was increased by about 70% (from 4.9 to 8.3 kg plant−1). Organic matter supplementation may provide the basis for a more favorable sink/source balance for tomato cropping. We conclude that organic supplementation represents a beneficial management measure to increase the effectiveness of soil solarization, and that these results provide encouragement for the future commercial application of this environmentally-friendly technique

Evolution of cold-air-pooling processes in complex terrain

This document is the Accepted Manuscript version. The final publication is available at Springer via: https://doi.org/10.1007/s10546-013-9885-zElucidating cold-air-pooling processes forms part of the longstanding problem of parametrizing the effects of complex terrain in larger-scale numerical models. The Weather Research and Forecasting model has been set-up and run at high resolution over an idealized alpine-valley domain with a width of order 10 km, to investigate the four-dimensional variation of key cold-air-pooling forcing mechanisms, under decoupled stable conditions. Results of the simulation indicated that the total average valley-atmosphere cooling is driven by a complex balance/interplay between radiation and dynamical effects. Three fairly distinct regimes in the evolution of cold-air-pooling processes have been identified. Starting about 1 h before sunset, there is an initial 30-min period when the downslope flows are initiated and the total average valley-atmosphere instantaneous cooling is dominated by radiative heat loss. A period of instability follows, when there is a competition between radiation and dynamical effects, lasting some 90 min. Finally, there is a gradual reduction of the contribution of radiative cooling from 75 to 37 %. The maximum cold-air-pool intensity corresponds to the time of minimum radiative cooling, within the period of instability. Although, once the flow is established, the valley atmosphere cools at broadly similar rates by radiation and dynamical effects, overall, radiation effects dominate the total average valley-atmosphere cooling. Some of the intricacies of the valley mixing have been revealed. There are places where the dynamics dominate the cooling and radiation effects are minor. Characteristics of internal gravity waves propagating away from the slopes are discussedPeer reviewe

Mapping Frost-Sensitive Areas with a Three-Dimensional Local-Scale Numerical Model. Part I. Physical and Numerical Aspects

Abstract Radiative frost is one of the most severe weather conditions that affects agricultural activities in many parts of the world. Since various protective methods to reduce frost impact are available, refinements of frost forecasting methodologies should provide economical benefits. In the present study, a three-dimensional numerical local-scale model for the simulation of the microclimate near the ground surface of nonhomogeneous regions during radiative frost events was developed. The model is based on the equations of motion, heat, humidity and continuity in the atmosphere and the equations of heat and moisture diffusion in the soil. Emphasis was given in establishing a refined formulation of energy budget equations for soil surface and plant canopy Additionally, an improved finite difference scheme procedure for approximating horizontal derivatives in a terrain-following coordinate system was introduced. The sensitivity of the model to various parameters that way affect the nocturnal minimum temp..