Effect of sharp vegetation boundary on the convective atmospheric boundary layer

An abrupt change of turbulent fluxes and cloud formation were found during the Bunny Fence experiment in the southwestern Australia at a sharp boundary between agricultural and native vegetation. It is suggested that this is a direct consequence of distinct coherent structures formed within atmospheric sheared convective boundary layers. Using large-eddy simulations (LES), it was found that a boundary-attached roll circulation appears at the sharp vegetation boundary. Model calculations revealed significant horizontal heat and moisture flux from the agricultural to the native vegetation area. The additional moisture flux may explain the observed increased cloud formation over the native vegetation as well as contribute to increased rainfall over the native vegetation

Assessing the effect of machine automation on operator heart and breathing rate during mechanical harvesting of wild blueberries

Wild blueberries (Vaccinium angustifolium Ait.) are among eastern Canada's most economically important crops. Despite this, the industry faces significant labor shortages required to harvest the over 69 000 ha of wild blueberry land each year. Automation of the wild blueberry is among the leading areas of wild blueberry research. The requirement to automate several different aspects of the harvester means that at present an operator is still required in the tractor. To determine the impacts that automation features have on an operator, and to assess the potential to replace skilled operators with unskilled ones, heart and respiration rates were monitored across various automatic, semiautomatic and manual harvesting conditions. Across both years of the study, the skilled operator experienced a 13.83% decrease in average heart rate under the fully automated condition versus the fully manual condition. Similarly, the new operator experienced a 19.03% decrease in average heart rate for the same scenario. While a conclusive determination cannot be made due to the significant interaction effect, it was likewise interesting to note that the skilled operator seemed to benefit more from the automated head adjustment while the new operator seemed to benefit more from the autosteer. Respiration rate data did not yield a conclusive trend, though the highest respiration rates were seen under the fully manual harvesting condition in all but the 2022 new operator data. In all, this study lays significant groundwork in the justification of automation for addressing the skilled labor shortage and for the eventual full automation of the wild blueberry harvester

The involvement of the transpirational bypass flow in sodium uptake by high- and low-sodium-transporting lines of rice developed through intravarietal selection

We report the characterization of high- and low-sodium-transporting lines developed by intravarietal selection within a cultivar, IR36, of rice (Oryza sativa L.). The purpose was to investigate the mechanistic basis of sodium uptake in material in which differences in salt uptake could be isolated from the many other morphological and physiological characteristics that affect the phenotypic expression of salt tolerance. The lines differed in mean sodium transport by a factor of 2. They differed in vigour and water use efficiency, which are characters that modify the effects of salt transport, by only 12% or 13%. The lines did not differ significantly in other physiological traits that are components of salt resistance: compartmentalization at the leaf and cellular levels. There was a strong correlation between the transport of sodium and a tracer for apoplastic pathways (trisodium, 3-hydroxy-5,8,10-pyrene trisulphonic acid, PTS) in both lines. The regression coefficient for sodium transport on PTS transport was the same in both lines. The individual variation in PTS transport was similar to that in sodium transport, and the variation in the transport of both was very much greater than the variation in any other character studied. The high-sodium-transporting line took up proportionately more PTS than the low-sodium-transporting line. It is concluded that the transpirational bypass flow is of major importance in sodium uptake by rice and that selection for differences in sodium transport has been brought about by selection for heritable differences in the bypass flow

New areas of polar lows over the Arctic as a result of the decrease in sea ice extent

Three mesocyclones (MCs) over the Russian (Eastern) Arctic are investigated using multispectral satellite remote sensing data, surface analysis maps, and reanalysis data. Advanced retrieval algorithms are used for estimating the geophysical parameter from satellite passive microwave measurements. These methods allow reconstructing in full the geophysical parameter fields characterizing polar lows. Synoptic analysis along with cloud image, atmospheric water vapor content, cloud liquid water content, and sea surface wind speed field analysis show that, while the Arctic sea ice retreats, new areas of open water appear where MCs can arise. A detailed study of several polar low cases reveals the typical conditions of their formation and development. Further studies are in demand due to the danger of MC extreme events for navigation, transport, and fishery operations in these unexplored regions

Anatomia de raízes de nove espécies de Bromeliaceae (Poales) da região amazônica do estado de Mato Grosso, Brasil Anatomy of the roots of nine species of Bromeliaceae (Poales) from the Amazon, Mato Grosso, Brazil

Este estudo busca caracterizar raízes de Bromeliaceae: Aechmea bromeliifolia, A. castelnavii, A. mertensii (Bromelioideae), Dyckia duckei, D. paraensis, D. racemosa (Pitcairnoideae), Tillandsia adpressiflora, T. didistachae e T. paraensis (Tillandsioideae) ocorrentes nas regiões amazônicas (Mato Grosso-MT), procurando levantar caracteres de valor taxonômico e significado ecológico. As espécies estudadas são epífitas e suas raízes se caracterizam por apresentar velame pluriestratificado, córtex diferenciado, endoderme e periciclo unisseriados, cilindro vascular poliarco e medula com células de paredes espessadas. Estruturas anatômicas como: número de camadas e tipo de espessamento das paredes das células do velame, tipo de espessamento de parede da exoderme e endoderme, presença de idioblastos contendo cristais e número de pólos de protoxilema agrupam as espécies nos diferentes gêneros e subfamílias. A presença de canais de mucilagem no córtex de A. castelnavii relatados pela primeira vez na literatura para Bromeliaceae é caráter diagnóstico. As raízes de Dyckia e Tillandsia apresentam maior número de caracteres comuns, representando maior similaridade entre Pitcairnioideae e Tillandsioideae. Raízes com velame, exoderme com células de paredes espessadas constituindo uma camada mecânica, canais de mucilagem, lacunas de ar no córtex interno e idioblastos com cristais são estruturas adaptativas ao hábito epifítico.<br>This study aimed to characterize the roots of Bromeliaceae, Aechmea bromeliifolia, A. castelnavii, A. mertensii (Bromelioideae), Dyckia duckei, D. paraensis, D. racemosa (Pitcairnoideae), Tillandsia adpressiflora, T. didistachae and T. paraensis (Tillandsioideae), that occur in Amazonian regions (Mato Grosso-MT), in order to find features of taxonomic value and ecological importance. The studied species are epiphytes and their roots are characterized by a multi-layered velamen, differentiated cortex, uniseriate endodermis and pericycle, polyarch vascular cylinder and medulla with thickened cell walls. Anatomical structures, such as the number of layers and kind of cell wall thickening of the velamen, the kind of thickening of the exodermis and endodermis walls, the presence of idioblasts containing crystals and the number of protoxylem poles help seperate these species within different genera and subfamilies. The presence of mucilage canals in the cortex of A. castelnavii is a diagnostic feature. The roots of Dyckia and Tillandsia share more common features, so there is greater similarity between Pitcairnioideae and Tillandsioideae. Roots with velamen, an exodermis with thickened cell walls constituting a mechanical layer, mucilage canals, air gaps in the inner cortex and idioblasts with crystals are structures adapted to the epiphytic habit