67 research outputs found
Condensation and partial pressure change as a major cause of airflow: experimental evidence
The dominant model of atmospheric circulation is based on the notion that hot air rises, creating horizontal winds. A second major driver has been proposed in the biotic pump theory (BPT), by which intense condensation is the prime cause of surface winds from ocean to land. Critics of the BPT argue that air movement resulting from condensation is isotropic. This paper explores the physics of water condensation under mild atmospheric conditions, within a purpose-designed square-section 4.8m-tall closed-system structure. The data show a highly significant correlation (R2 >0.96, p value <0.001) between observed airflows and partial pressure changes from condensation. The assumption that condensation of water vapour is always isotropic is therefore incorrect
Further experimental evidence that condensation is a major cause of airflow
This paper further explores the physics of water condensation, using an experimental structure designed for that purpose. The data show a highly significant correlation (R2 >0.94, p value <0.001) between observed airflows and partial pressure changes from condensation, when the results of different experiments are pooled. Changes in air density on cooling provide insufficient energy to account for the airflow. The finding is that the kinetic energy of the chilled air falls short by an order of magnitude, even to move a relatively small proportion of the 20 kg of air contained within the structure. Meanwhile the physics of condensation indicate a surplus of kinetic energy is made available from the air surrounding the locus of condensation. At low rates of condensation a considerable proportion of the available kinetic energy in the enclosed air is absorbed in friction and turbulence. That proportion reduces with higher rates of condensation
Inhibition of Bruton's TK regulates macrophage NF-kappa B and NLRP3 inflammasome activation in metabolic inflammation
Background and Purpose: There are no medications currently available to treat metabolic inflammation. Bruton's tyrosine kinase (BTK) is highly expressed in monocytes and macrophages and regulates NF-\u3baB and NLRP3 inflammasome activity; both propagate metabolic inflammation in diet-induced obesity. Experimental Approach: Using an in vivo model of chronic inflammation, high-fat diet (HFD) feeding, in male C57BL/6J mice and in vitro assays in primary murine and human macrophages, we investigated if ibrutinib, an FDA approved BTK inhibitor, may represent a novel anti-inflammatory medication to treat metabolic inflammation. Key Results: HFD-feeding was associated with increased BTK expression and activation, which was significantly correlated with monocyte/macrophage accumulation in the liver, adipose tissue, and kidney. Ibrutinib treatment to HFD-fed mice inhibited the activation of BTK and reduced monocyte/macrophage recruitment to the liver, adipose tissue, and kidney. Ibrutinib treatment to HFD-fed mice decreased the activation of NF-\u3baB and the NLRP3 inflammasome. As a result, ibrutinib treated mice fed HFD had improved glycaemic control through restored signalling by the IRS-1/Akt/GSK-3\u3b2 pathway, protecting mice against the development of hepatosteatosis and proteinuria. We show that BTK regulates NF-\u3baB and the NLRP3 inflammasome specifically in primary murine and human macrophages, the in vivo cellular target of ibrutinib. Conclusion and Implications: We provide \u201cproof of concept\u201d evidence that BTK is a novel therapeutic target for the treatment of diet-induced metabolic inflammation and ibrutinib may be a candidate for drug repurposing as an anti-inflammatory agent for the treatment of metabolic inflammation in T2D and microvascular disease
The key physical parameters governing frictional dissipation in a precipitating atmosphere
Precipitation generates small-scale turbulent air flows the energy of which
ultimately dissipates to heat. The power of this process has previously been
estimated to be around 2-4 W m-2 in the tropics: a value comparable in
magnitude to the dynamic power of the global circulation. Here we suggest that
this previous power estimate is approximately double the true figure. Our
result reflects a revised evaluation of the mean precipitation path length Hp.
We investigate the dependence of Hp on surface temperature,relative
humidity,temperature lapse rate and degree of condensation in the ascending
air. We find that the degree of condensation,defined as the relative change of
the saturated water vapor mixing ratio in the region of condensation, is a
major factor determining Hp. We estimate from theory that the mean large-scale
rate of frictional dissipation associated with total precipitation in the
tropics lies between 1 and 2 W m-2 and show that our estimate is supported by
empirical evidence. We show that under terrestrial conditions frictional
dissipation constitutes a minor fraction of the dynamic power of
condensation-induced atmospheric circulation,which is estimated to be at least
2.5 times larger. However,because Hp increases with surface temperature Ts, the
rate of frictional dissipation would exceed that of condensation-induced
dynamics, and thus block major circulation, at Ts >~320 K in a moist adiabatic
atmosphere.Comment: 12 pp, 2 figure
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Genetic analysis of a major international collection of cultivated apple varieties reveals previously unknown historic heteroploid and inbred relationships
Domesticated apple (Malus x domestica Borkh.) is a major global crop and the genetic diversity held within the pool of cultivated varieties is important for the development of future cultivars. The aim of this study was to investigate the diversity held within the domesticated form, through the analysis of a major international germplasm collection of cultivated varieties, the UK National Fruit Collection, consisting of over 2,000 selections of named cultivars and seedling varieties. We utilised Diversity Array Technology (DArT) markers to assess the genetic diversity within the collection. Clustering attempts, using the software STRUCTURE revealed that the accessions formed a complex and historically admixed group for which clear clustering was challenging. Comparison of accessions using the Jaccard similarity coefficient allowed us to identify clonal and duplicate material as well as revealing pairs and groups that appeared more closely related than a standard parent-offspring or full-sibling relations. From further investigation, we were able to propose a number of new pedigrees, which revealed that some historically important cultivars were more closely related than previously documented and that some of them were partially inbred. We were also able to elucidate a number of parent-offspring relationships that had resulted in a number of important polyploid cultivars. This included reuniting polyploid cultivars that in some cases dated as far back as the 18th century, with diploid parents that potentially date back as far as the 13th century
Vientos y lluvia: El papel de la bomba biótica
En 2007, Anastassia Makarieva y Victor Gorshkov elaboraron la Teoría de la Bomba Biótica (Makarieva A. a., 2007). Los dos científicos, matemáticos/físicos del Instituto de Física Nuclear de San Petersburgo, Rusia, describieron la Teoría de la Bomba Biótica (BPT) en términos de las leyes fundamentales de la física relativas al cambio de fase cuando el agua se evapora y luego se condensa a través del proceso de formación de nubes, a medida que el aire húmedo se eleva en la troposfera y se enfría con la altitud. El grado de saturación del vapor de agua sigue la ecuación de Clausius-Clapeyron para los gases ideales, teniendo en cuenta la temperatura (Kelvin), la humedad relativa y la presión barométrica
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