446 research outputs found
Effective crustal permeability controls fault evolution: An integrated structural, mineralogical and isotopic study in granitic gneiss, Monte Rosa, Northern Italy
Two dextral faults within granitic gneiss in the Monte Rosa nappe, northern Italy reveal key differences in their evolution controlled by evolving permeability and water/rock reactions. The comparison reveals that identical host rock lithologies develop radically different mineralogies within the fault zones, resulting in fundamentally different deformation histories. Oxygen and hydrogen isotope analyses coupled to microstructural characterisation show that infiltration of meteoric water occurred into both fault zones. The smaller Virgin Fault shows evidence of periodic closed system behaviour, which promoted the growth of hydrothermal K-feldspar, whilst the more open system behaviour of the adjacent Ciao Ciao Fault generated a weaker muscovite-rich fault core, which promoted a step change in fault evolution. Effective crustal permeability is a vital control on fault evolution and, coupled to the temperature (i.e. depth) at which key mineral transformations occur, is probably a more significant factor than host rock strength in controlling fault development. The study suggests that whether a fault in granitic basement grows into a large structure may be largely controlled by the initial hydrological properties of the host rocks. Small faults exposed at the surface may therefore be evolutionary âdead-endsâ that typically do not represent the early stages in the development of larger faults
MUSE observations of a changing-look AGN I: The re-appearance of the broad emission lines
Optical changing-look Active Galactic Nuclei (AGN) are a class of sources
that change type within a short timescale of years or decades. This change is
characterised by the appearance or disappearance of broad emission lines, often
associated with dramatic AGN continuum flux changes that are orders of
magnitude larger than those expected from typical AGN variability. In this work
we study for the first time the host galaxy of a changing-look AGN, Mrk 590,
using high spatial resolution optical and near-infrared observations. We
discover that after ~ 10 yr absence, the optical broad emission lines of Mrk
590 have reappeared. The AGN optical continuum flux however, is still ~ 10
times lower than that observed during the most luminous state in the 1990s. The
host galaxy shows a 4.5 kpc radius star-forming ring with knots of ionised and
cold molecular gas emission. Extended ionised and warm molecular gas emission
are detected in the nucleus, indicating that there is a reservoir of gas as
close as 60 pc from the black hole. We observe a nuclear gas spiral between
radii r ~ 0.5 - 2 kpc, which has been suggested as a dynamical mechanism able
to drive the necessary gas to fuel AGN. We also discover blue-shifted and high
velocity dispersion [O III] emission out to a radius of 1 kpc, tracing a
nuclear gas outflow. The gas dynamics in Mrk 590 suggest a complex balance
between gas inflow and outflow in the nucleus of the galaxy.Comment: Accepted for publication in MNRA
Isolation and Characterization of Organosolv Lignins From Wheat Straw
Delignification of wheat straw with aqueous methanol, ethanol, l-propanol, n-butanol, dioxane, and acetone in the presence of acid catalyst (0.02 N H2SO4) at low temperature (75°C) for 2 h was studied. The effect of ethanol-water ratios on the yield of dissolved lignin is also reported here. There was no significant difference in the organosolv lignin yields among the various organic solvents used, which accounted for 24-28% of the total amount of acidic chlorite lignin present in wheat straw. Increase of ethanol-water volume ratio from 40/60 to 70/30 resulted in raising lignin yields from 25 to 31%, while the reverse yield from 31 to 24% appeared in the increase of volume ratio from 70/30 to 90/10. The isolated organosolv lignin fractions contained low amounts of polysaccharide sugars (4.5-5.3%) and had low average molecular weights (1190-1650 Da), which corresponded with the ball-milling lignin, enzyme lignin, and alkali lignin obtained from wheat straw. The predominant components of the alkali nitrobenzene oxidation products were found to be vanillin and syringaldehyde. The yield of vanillin was slightly higher than that of syringaldehyde in all the nitrobenzene oxidation products of the isolated organosolv lignin preparations
Living with and without an intestinal stoma: Factors that promote psychological well-being and self-care: A cross sectional study.:Psychological well-being and stoma
Abstract Aims This study compared those living with and without an intestinal stoma in relation to physical and psychological health, stress and coping, quality of life and resilience. Also, identifying factors that could be used to promote better selfâcare in stoma patients in the future. Design A crossâsectional and comparative study design was employed. Methods Participants were recruited via email and social media (Facebook and Twitter) between August 2018 and March 2019, to complete an online survey. The data were analysed using analysis of variance to examine group difference and a series of hierarchical linear regression analyses determining predictors of psychological wellâbeing. Results Of 278 participants aged 18â68âyears who completed the survey, 129 (46%) had a stoma and reported significantly poorer physical health. Approximately oneâfifth experienced problems with stoma management. Psychological wellâbeing was mediated by the duration of living with a stoma (under 3âyears) and frequency of leaks (weekly and monthly)
The effect of selected synbiotics on microbial composition and short-chain Fatty Acid production in a model system of the human colon.
Prebiotics, probiotics and synbiotics can be used to modulate both the composition and activity of the gut microbiota and thereby potentially affecting host health beneficially. The aim of this study was to investigate the effects of eight synbiotic combinations on the composition and activity of human fecal microbiota using a four-stage semicontinuous model system of the human colon.Carbohydrates were selected by their ability to enhance growth of the probiotic bacteria Lactobacillus acidophilus NCFM (NCFM) and Bifidobacterium animalis subsp. lactis Bl-04 (Bl-04) under laboratory conditions. The most effective carbohydrates for each probiotic were further investigated, using the colonic model, for the ability to support growth of the probiotic bacteria, influence the composition of the microbiota and stimulate formation of short-chain fatty acids (SCFA).The following combinations were studied: NCFM with isomaltulose, cellobiose, raffinose and an oat β-glucan hydrolysate (OBGH) and Bl-04 with melibiose, xylobiose, raffinose and maltotriose. All carbohydrates showed capable of increasing levels of NCFM and Bl-04 during fermentations in the colonic model by 10(3)-10(4) fold and 10-10(2) fold, respectively. Also the synbiotic combinations decreased the modified ratio of Bacteroidetes/Firmicutes (calculated using qPCR results for Bacteroides-Prevotella-Porphyromonas group, Clostridium perfringens cluster I, Clostridium coccoides - Eubacterium rectale group and Clostridial cluster XIV) as well as significantly increasing SCFA levels, especially acetic and butyric acid, by three to eight fold, as compared to the controls. The decreases in the modified ratio of Bacteroidetes/Firmicutes were found to be correlated to increases in acetic and butyric acid (p=0.04 and p=0.03, respectively).The results of this study show that all synbiotic combinations investigated are able to shift the predominant bacteria and the production of SCFA of fecal microbiota in a model system of the human colon, thereby potentially being able to manipulate the microbiota in a way connected to human health
Intergroup struggles over victimhood in violent conflict: The victim-perpetrator paradigm
Most groups in violent, intergroup conflict perceive themselves to be the primary or sole
victims of that conflict. This often results in contention over who may claim victim status
and complicates a central aim of post-conflict processes, which is to acknowledge and
address harms experienced by the victims. Drawing from victimology scholarship and
intergroup relations theory, this article proposes the victim-perpetrator paradigm as a
framework to analyse how, why and to what end groups in conflict construct and maintain
their claims to the moral status of victim. This interdisciplinary paradigm builds on the
knowledge that groups utilise the âideal victimâ construction to exemplify their own
innocence and blamelessness in contrast to the wickedness of the perpetrator, setting the
two categories as separate and mutually exclusive even where experiences of violence
have been complex. Additionally, this construction provides for a core intergroup need
to achieve positive social identity, which groups may enhance by demonstrating a
maximum differentiation between the in-group as victims and those out-groups identified
as perpetrators. The paradigm contributes greater knowledge on the social roots of victim
contention in conflict, as well as how groups legitimise their violence against out-groups
during and after conflict
Resistome analysis of global livestock and soil microbiomes
Publication history: Accepted - 24 May 2022: Published online - 7 July 2022Antimicrobial resistance (AMR) is a serious threat to public health globally; it is estimated
that AMR bacteria caused 1.27 million deaths in 2019, and this is set to rise to 10 million
deaths annually. Agricultural and soil environments act as antimicrobial resistance gene
(ARG) reservoirs, operating as a link between different ecosystems and enabling the mixing
and dissemination of resistance genes. Due to the close interactions between humans
and agricultural environments, these AMR gene reservoirs are a major risk to both human
and animal health. In this study, we aimed to identify the resistance gene reservoirs present
in four microbiomes: poultry, ruminant, swine gastrointestinal (GI) tracts coupled with
those from soil. This large study brings together every poultry, swine, ruminant, and soil
shotgun metagenomic sequence available on the NCBI sequence read archive for the
first time. We use the ResFinder database to identify acquired antimicrobial resistance
genes in over 5,800 metagenomes. ARGs were diverse and widespread within the
metagenomes, with 235, 101, 167, and 182 different resistance genes identified in the
poultry, ruminant, swine, and soil microbiomes, respectively. The tetracycline resistance
genes were the most widespread in the livestock GI microbiomes, including tet(W)_1,
tet(Q)_1, tet(O)_1, and tet(44)_1. The tet(W)_1 resistance gene was found in 99% of
livestock GI tract microbiomes, while tet(Q)_1 was identified in 93%, tet(O)_1 in 82%, and
finally tet(44)_1 in 69%. Metatranscriptomic analysis confirmed these genes were ârealâ
and expressed in one or more of the livestock GI tract microbiomes, with tet(40)_1 and
tet(O)_1 expressed in all three livestock microbiomes. In soil, the most abundant ARG
was the oleandomycin resistance gene, ole(B)_1. A total of 55 resistance genes were
shared by the four microbiomes, with 11 ARGs actively expressed in two or more
microbiomes. By using all available metagenomes we were able to mine a large number
of samples and describe resistomes in 37 countries. This study provides a global insight
into the diverse and abundant antimicrobial resistance gene reservoirs present in both
livestock and soil microbiomes.This work was supported by the Northern Irish Department of Agriculture, Environment and Rural Affairs
Ethanol production from steam exploded rapeseed straw and the process simulation using artificial neural networks
- âŚ