676 research outputs found
Measuring Column Densities in Quasar Outflows: VLT Observations of QSO 2359-1241
We present high resolution spectroscopic VLT observations of the outflow seen
in QSO 2359-1241. These data contain absorption troughs from five resonance Fe
II lines with a resolution of ~7 km/s and signal-to-noise ratio per resolution
element of order 100. We use this unprecedented high quality data set to
investigate the physical distribution of the material in front of the source,
and by that determine the column densities of the absorbed troughs. We find
that the apparent optical depth model gives a very poor fit to the data and
greatly underestimates the column density measurements. Power-law distributions
and partial covering models give much better fits with some advantage to
power-law models, while both models yield similar column density estimates. The
better fit of the power-law model solves a long standing problem plaguing the
partial covering model when applied to large distance scale outflow: How to
obtain a velocity dependent covering factor for an outflow situated at
distances thousands of time greater than the size of the AGN emission source.
This problem does not affect power-law models. Therefore, based on the better
fit and plausibility of the physical model, we conclude that in QSO 2359-1241,
the outflow covers the full extent of the emission source but in a
non-homogeneous way.Comment: 27 pages, 6 figures, to appear on ApJ Jul 10. The full (online)
version of figure 2 can be obtained here:
http://www.phys.vt.edu/~arav/f2_online_version.p
Impacts of land use on an insectivorous tropical bat: The importance of mercury, physio-immunology and trophic position
International audienceDeforestation, agricultural intensification, and habitat homogenization are critical threats to biodiversity in Southeast Asia. Limited information is available on the trophic and physiological responses of tropical animals to these environmental changes. The wrinkle-lipped free-tailed bat Chaerephon plicatus is a cave roosting species that is experiencing population declines across Southeast Asia, where landscapes have been drastically modified. In our study site in central Thailand, we tested the hypothesis that wrinkle-lipped free-tailed bats living in landscapes that contrast in heterogeneity and land-use differed in mercury contamination, trophic position and physio-immunological status. Bats from less heterogeneous landscapes (dominated by rice crops, absence of large forest patches) occupied a lower trophic position than conspecifics from more heterogeneous landscapes (including large forest patches). Additionally, bats from these habitats had lower concentrations of mercury in erythrocytes, lower body mass, higher antioxidant superoxide dismutase (SOD), lower antioxidant glutathione peroxidase (GPx) and lower values of the GPx/SOD ratio than bats from more heterogeneous landscapes. Individual bat mercury concentrations were positively correlated with body mass and two immune markers (lysozyme and immunoglobulin) but were negatively correlated with plasma non-enzymatic antioxidant capacity. Our results suggest various links between landscape heterogeneity, mercury accumulation/exposure, and health status of wildlife in Southeast Asian countries
Dampening the DAMPs: how plants maintain the homeostasis of cell wall molecular patterns and avoid hyper-immunity
Several oligosaccharide fragments derived from plant cell walls activate plant immunity and behave as typical damage-associated molecular patterns (DAMPs). Some of them also behave as negative regulators of growth and development, and due to their antithetic effect on immunity and growth, their concentrations, activity, time of formation, and localization is critical for the so-called “growth-defense trade-off.” Moreover, like in animals, over accumulation of DAMPs in plants provokes deleterious physiological effects and may cause hyper-immunity if the cellular mechanisms controlling their homeostasis fail. Recently, a mechanism has been discovered that controls the activity of two well-known plant DAMPs, oligogalacturonides (OGs), released upon hydrolysis of homogalacturonan (HG), and cellodextrins (CDs), products of cellulose breakdown. The potential homeostatic mechanism involves specific oxidases belonging to the family of berberine bridge enzyme-like (BBE-like) proteins. Oxidation of OGs and CDs not only inactivates their DAMP activity, but also makes them a significantly less desirable food source for microbial pathogens. The evidence that oxidation and inactivation of OGs and CDs may be a general strategy of plants for controlling the homeostasis of DAMPs is discussed. The possibility exists of discovering additional oxidative and/or inactivating enzymes targeting other DAMP molecules both in the plant and in animal kingdoms
Butyrylcholinesterase and Acetylcholinesterase polymorphisms in Multiple Sclerosis patients: Implication in peripheral inflammation
Multiple Sclerosis (MS) is an autoimmune disease, having not fully understood aetiology, and both genetic and environmental factors contribute to the pathogenesis of the disease. The cholinergic system has been indicated as a mediator of neuro-immune interactions, as well as an internal regulator of immune responses. The aim of the present research was to assess the associations between BChE and AChE genetic variations and serum cholinergic and inflammatory profiles in 102 Relapsing Remitting-MS patients and 117 healthy controls. An increased frequency of the BChE K-allele in MS patients as compared to controls was found. In addition, data showed that patients had higher BChE enzymatic activity, which is increased by the presence of the polymorphic allele and reduced amounts of circulating ACh. AChE polymorphism was significantly associated to reduced activity in both patients and controls. We propose that serum BChE and AChE activity may be used as a secondary markers to assess the role of non-neuronal cholinergic system in regulating peripheral inflammation via ACh regulation. This pilot study shed light on the role of the non-neuronal cholinergic system in immune cells to better understand MS pathogenesis. The cross-talk between the periphery and the CNS could have a new undescribed crucial role for MS, regarded as a systemic disease
Evaluating the impact of synthesised scent enrichment on behavioural and endocrine responses in captive alaotran gentle lemurs (Hapalemur alaotrensis)
© 2024 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/jzbg5040036The Alaotran gentle lemur (Hapalemur alaotrensis) is one of the world’s most endangered primates and shows low success rates in captive breeding programmes. This study tested biologically relevant scent enrichment using two synthesised mixtures likely to convey information about female fertility on the behaviour of three unsuccessful breeding pairs in captivity. Specifically, we compared the baseline and enrichment periods by combining behavioural observations (n = 240 h) with faecal endocrinology (n = 80 samples), focussing on cortisol and testosterone measurements via enzyme immunoassay techniques. Then, we tested two different mixtures to assess potential behavioural differences and evaluate the effectiveness of olfactory enrichment using scented and unscented cotton strips. Olfactory behaviours differed by sex and enrichment conditions, with both sexes exhibiting increased behaviours during enrichment compared to the baseline. Sexual behaviours increased during the enrichment period, with variations in frequency between males and females depending on the condition. No significant changes were observed in faecal cortisol levels. However, one male showed a significant increase in testosterone during the second enrichment mixture. Nevertheless, overall differences between baseline and enrichment were not significant. Our findings suggest that while the scent enrichment showed limited effectiveness, biologically meaningful scents may trigger species-specific behaviours.This work was supported by the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie grant agreement [no. 890341 to S.F. and S.V.]. Lab work and publication fees were funded by the University of Wolverhampton’s Research Investment Fund scheme—Phase 4 [to S.V.].Published onlin
Endocarditis of Native Valve due to Proteus mirabilis: Case Report and Literature Review
AbstractEndocarditis due to Proteus mirabilis is very uncommon and the optimal surgical and/or antibiotic treatment is not well defined. Guidelines from the AHA and ESC recommend prolonged courses of combined antibiotic therapy but information regarding the clinical presentation, the choice of treatment, the surgical management, and the duration of therapy can only be taken from clinical cases reported in literature. We describe a case of native valve endocarditis due to Proteus mirabilis, successfully treated with antibiotic therapy alone with a review of the relevant literature on this topic
Temporal binding window and sense of agency are related processes modifiable via occipital tACS
The temporal binding window refers to the time frame within which temporal grouping of sensory information takes place. Sense of agency is the feeling of being in control of one’s actions, and their associated outcomes. While previous research has shown that temporal cues and multisensory integration play a role in sense of agency, no studies have directly assessed whether individual differences in the temporal binding window and sense of agency are associated. In all three experiments, to assess sense of agency, participants pressed a button triggering, after a varying delay, the appearance of the circle, and reported their sense of agency over the effect. To assess the temporal binding window a simultaneity judgment task (Experiment 1) and a double-flash illusion task (Experiment 2 and 3) was also performed. As expected, the temporal binding window correlated with the sense of agency window. In Experiment 3, these processes were modulated by applying occipital tACS at either 14Hz or 8Hz. We found 14Hz tACS stimulation was associated with narrower temporal biding window and sense of agency window. Our results suggest the temporal binding window and the time window of sense of agency are related. They also point towards a possible underlying neural mechanism (alpha peak frequency) for this association
Distribution of Engraulis encrasicolus eggs and larvae in relation to coastal oceanographic conditions (the South-western Adriatic Sea case study)
Identification of potential spawning and nursery areas of European anchovy (Engraulis encrasicolus) represents an essential step in the management of a resource which is of fundamental importance both for fishery and pelagic trophic web. Egg and larvae occurrence from ichthyoplankton surveys (2012 - 2015) in the South Western Adriatic Sea were examined to understand the mechanisms that control their distribution. Egg and larvae densities varied through the years with the highest values recorded in 2012 and the lowest in 2014. Positive correlations between eggs and larvae with zooplankton were observed. When quotient analysis was used to find relations with environmental and biological variables, the results pointed out an egg preference for depth between 91 and 120 m and an avoidance between 11 and 30 m. Moreover, egg avoidances for high values of chlorophyll-a (> 0.52 mg m-3) and low values of zooplankton biomass ( 151 m; preference for high zooplankton biomass (> 1000 mg m-2) and avoidance for low biomass (< 299 mg m-2). These correlations and the quotient values suggest that egg and larvae distribution in the South-Western Adriatic Sea is mainly driven by food availability and depth
Palliative care in the emergency department as seen by providers and users: a qualitative study
Background Much effort has been made to explore how patients with advanced chronic illness and their families experience care when they attend the Emergency Department, and many studies have investigated how healthcare professionals perceive Palliative Care provision in the Emergency Department. Various models exist, but nonetheless incorporating palliative care into the Emergency Department remains challenging. Considering both healthcare professionals\u2019 and users\u2019 perspective on problems encountered in delivering and receiving appropriate palliative care within this context may provide important insight into meaningful targets for improvements in quality of care. Accordingly, this study aims at exploring issues in delivering palliative care in the Emergency Department from the perspective of both providers and users, as part of a larger project on the development and implementation of a quality improvement program in Italian Emergency Departments. Methods A qualitative study involving focus group interviews with Emergency Department professionals and semi-structured interviews with patients with palliative care needs in the Emergency Department and their relatives was conducted. Both datasets were analyzed using Thematic Analysis. Results Twenty-one healthcare professionals, 6 patients and 5 relatives participated in this study. Five themes were identified: 1) shared priorities in Emergency Department among healthcare professionals and patients, 2) the information provided by healthcare professionals and that desired by relatives, 3) perception of environment and time, 4) limitations and barriers to the continuity of care, and 5) the contrasting interpretations of giving and receiving palliative care. Conclusions This study provides insights into targets for changes in Italian Emergency Departments. Room for improvement relates to training for healthcare professionals on palliative care, the development of a shared care pathway for patients with palliative care needs, and the optimization of Emergency Department environment. These targets will be the basis for the development of a quality improvement program in Italian Emergency Departments
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