Vertical coupling of the middle atmosphere during stratospheric warming events

A 20 year simulation of the high-top atmospheric General Circulation Model (GCM) HAMMONIA is used to investigate internally produced Sudden Stratospheric Warmings (SSWs). We detect 19 major SSWs and evaluate the model results by comparison to the ERA40 reanalysis dataset. Composites are built to analyze the climatological characteristics of SSWs, in particular to investigate the mesospheric precursors and differences between vortex splits and displacements. The vertical coupling processes from the stratosphere to the lower thermosphere are studied using transformed Eulerian-mean (TEM) analysis and diagnostics concerning the role of gravity waves. Consistent to recent studies, we find a mesospheric cooling and a weaker thermospheric warming accompanying the SSW. The large anomalies in the zonal mean winds and temperatures are explained by the interactions of EP-Flux divergence, mean flow advection and parameterized momentum deposition of gravity waves. We present an algorithm, based on geopotential height, to classify the events. Nine SSWs can be characterized as vortex splits, 10 as displacements. The differences between the two types are statistically significant suggesting splits are associated with larger anomalies in temperature and zonal wind. Investigation of the longitudinal dependence of zonal winds demonstrates the asymmetry of the climatological winter and of single events. Therefore, we do not find a criterion to sufficiently detect SSWs using mesospheric winds prior to the central date

Interaction of a high-mass X-ray binary with the interstellar medium through stellar wind. The case of GX 301-2

GX 301-2 is a high-mass X-ray binary (HMXB) with strong stellar outflows. The evolution of these binaries can be closely related with the interstellar environment due to strong wind interactions. We try to constrain the energy injected in the interstellar medium by GX 301-2 through stellar wind using HAWK-I and Herschel data. We analysed HAWK-I images in four different filters (Br$\gamma$, H$_2$, J, and Ks) and tried to retrieve signatures of the impact of GX 301-2 on its environment. We used Herschel data to outline the interstellar medium and the Gaia DR3 catalogue to infer the proper motion of GX 301-2. Finally, we estimated the energy injected in the interstellar medium since the first supernova event of the HMXB. Using both HAWK-I and Herschel images, we deduce an approximation of the total mass injected from GX~301-2 in the interstellar medium of $M_{\rm inj} = 3.05 ^{+0.05}_{-0.03} 10^{-2} M_{\odot}$.Comment: 7 pages, 3 figure

Toward bioeconomy of a multipurpose cereal: Cell wall chemistry of Sorghum is largely buffered against stem sugar content

Background and Objectives Sorghum (Sorghum bicolor L. Moench) is a multipurpose crop with high potential for the bioeconomy. Ten sweet, grain and dual-purpose sorghum genotypes were compared with respect to sugar-related traits and cell wall composition. Findings The dual-purpose hybrids Ganymed, Zerberus, and Tarzan performed better with respect to plant height, cane weight, and juice volume, but the sweet genotype KIT1 produced the highest sugar concentration (°Brix) in the stem. Analytical sugar data demonstrate genotypic differences in terms of sugar composition and concentrations, with sucrose being dominant. The monosaccharide composition of the stem cell wall polysaccharides showed surprisingly little genotypic variability. Variations in contents of lignin and cell wall-bound hydroxycinnamate monomers were moderate. Conclusions Sweet, grain and dual-purpose sorghum genotypes differ widely in terms of sugar-related morphological parameters but are comparable with respect to their cell wall chemistry. Significance and Novelty The use of sorghum as a bioeconomy crop has mainly focused on the extraction of sugar for bioethanol production. However, besides cell wall polymers, the potential usage of hydroxycinnamates as platform molecules for the chemical industry may improve the valorization of the residues after sugar extraction. This application appears to be fairly independent of genotype, further increasing the potential of sorghum for the bioeconomy

Archetypes of Community Wildfire Exposure from National Forests of the Western US

Risk management typologies and their resulting archetypes can structure the many social and biophysical drivers of community wildfire risk into a set number of strategies to build community resilience. Existing typologies omit key factors that determine the scale and mechanism by which exposure from large wildfires occur. These factors are particularly important for land managing agencies like the US Forest Service, which must weigh community wildfire exposure against other management priorities. We analyze community wildfire exposure from national forests by associating conditions that affect exposure in the areas where wildfires ignite to conditions where exposure likely occurs. Linking source and exposure areas defines the scale at which crossboundary exposure from large wildfires occurs and the scale at which mitigation actions need to be planned. We find that the vast majority of wildfire exposure from national forests is concentrated among a fraction of communities that are geographically clustered in discrete pockets. Among these communities, exposure varies primarily based on development patterns and vegetation gradients and secondarily based on social and ecological management constraints. We describe five community exposure archetypes along with their associated risk mitigation strategies. Only some archetypes have conditions that support hazardous fuels programs. Others have conditions where managing community exposure through vegetation management is unlikely to suffice. These archetypes reflect the diversity of development patterns, vegetation types, associated fuels, and management constraints that exist in the western US and provide a framework to guide public investments that improve management of wildfire risk within threatened communities and on the public lands that transmit fires to them

Thymus zygis subsp. zygis an endemic portuguese plant: Phytochemical profiling, antioxidant, anti-proliferative and anti-inflammatory activities

Thymus zygis subsp. zygis is an endemic Portuguese plant belonging to the Thymus zygis species. Although T. zygis is commonly used as a condiment and as a medicinal herb, a detailed description of the polyphenol composition of hydroethanolic (HE) and aqueous decoction (AD) extracts is not available. In this work, we describe for the first time a detailed phenolic composition of Thymus zygis subsp. zygis HE and AD extracts, together with their antioxidant, anti-proliferative and anti-inflammatory activities. Unlike other Thymus species, T. zygis subsp. zygis extracts contain higher amounts of luteolin-(?)-O-hexoside. However, the major phenolic compound is rosmarinic acid, and high amounts of salvianolic acids K and I were also detected. T. zygis subsp. zygis extracts exhibited significant scavenging activity of ABTS+, hydroxyl (•OH), and nitric oxide (NO) radicals. Regarding the anti-proliferative/cytotoxic effect, tested against Caco-2 and HepG2 cells, the AD extract only slightly reduced cell viability at higher concentrations (IC50 > 600 µg/mL, 48 h exposure), denoting very low toxicity, while the HE extract showed a high anti-proliferative effect, especially at 48 h exposure (IC50 of 85.01 ± 15.10 μg/mL and 82.19 ± 2.46 μg/mL, for Caco-2 and HepG2, respectively). At non-cytotoxic concentrations, both extracts reduced the nitric oxide (NO) release by lipopolysaccharide (LPS)-stimulated RAW 264.7 cells (at 50 μg/mL, HE and AD extracts inhibited NO release in ~89% and 48%, respectively). In conclusion, the results highlight the non-toxic effect of aqueous extracts, both resembling the consumption of antioxidants in foodstuff or in functional food. Furthermore, the HE extract of T. zygis subsp. zygis is a source of promising molecules with antioxidant, anti-inflammatory and anticancer activities, highlighting its potential as a source of bioactive ingredients for nutraceutical and pharmaceutical industries

Phytochemical Composition and Antioxidant, Anti-Acetylcholinesterase, and Anti-α-Glucosidase Activity of Thymus carnosus Extracts: A Three-Year Study on the Impact of Annual Variation and Geographic Location

Thymus carnosus Boiss. is a near-threatened species, and, as for many species, its potential for medicinal purposes may be lost if measures towards plant protection are not taken. A way of preserving these species is to increase knowledge about their medicinal properties and economic potential. Thus, with the objective of studying the potentiality of introducing T. carnosus as a crop, the stability of the phytochemical profile of T. carnosus was studied during a period of three years by comparing the phytochemical profile of extracts obtained from plants harvested in two different edaphoclimatic locations, as well as by comparing the respective bioactivities, namely, antioxidant, antidiabetic, antiaging, and neuroprotective activities. It was reported, for the first time, the effect of annual variation and geographic location in the phytochemical composition of aqueous decoction and hydroethanolic extracts of T. carnosus. In addition, the presence of two salvianolic acid B/E isomers in T. carnosus extracts is here described for the first time. Despite the variations in phytochemical composition, according to harvesting location or year, T. carnosus extracts maintain high antioxidant activity, assessed by their capacity to scavenge ABTS•+, •OH , NO•, O2•− radicals, as well as to prevent β-carotene bleaching. All extracts presented significant potential to inhibit acetylcholinesterase (AChE), tyrosinase, and α-glucosidase, denoting neuroprotective, anti-aging, and anti-diabetic potential. In conclusion, the vegetative stage and location of harvest are key factors to obtain the maximum potential of this species, namely, a phytochemical profile with health benefit bioactivities

Heavy Element Nucleosynthesis in the Brightest Galactic Asymptotic Giant Branch stars

We present updated calculations of stellar evolutionary sequences and detailed nucleosynthesis predictions for the brightest asymptotic giant branch (AGB) stars in the Galaxy with masses between 5Msun to 9Msun, with an initial metallicity of Z =0.02 ([Fe/H] = 0.14). In our previous studies we used the Vassiliadis & Wood mass-loss rate, which stays low until the pulsation period reaches 500 days after which point a superwind begins. Vassiliadis & Wood noted that for stars over 2.5Msun the superwind should be delayed until P ~ 750 days at 5Msun. We calculate evolutionary sequences where we delay the onset of the superwind to pulsation periods of P ~ 700-800 days in models of M = 5, 6, and 7Msun. Post-processing nucleosynthesis calculations show that the 6 and 7Msun models produce the most Rb, with [Rb/Fe] ~ 1 dex, close to the average of most of the Galactic Rb-rich stars ([Rb/Fe] ~ 1.4 plus or minus 0.8 dex). Changing the rate of the 22Ne + alpha reactions results in variations of [Rb/Fe] as large as 0.5 dex in models with a delayed superwind. The largest enrichment in heavy elements is found for models that adopt the NACRE rate of the 22Ne(a,n)25Mg reaction. Using this rate allows us to best match the composition of most of the Rb-rich stars. A synthetic evolution algorithm is then used to remove the remaining envelope resulting in final [Rb/Fe] of ~ 1.4 dex although with C/O ratios > 1. We conclude that delaying the superwind may account for the large Rb overabundances observed in the brightest metal-rich AGB stars.Comment: 37 pages, accepted for publication in the Astrophysical Journal, minor modifications to text and Tables 2 and 3, reference adde