979 research outputs found
Adequate levels of dietary sulphur amino acids impart improved liver and gut health in juvenile yellowtail kingfish (Seriola lalandi)
The sulphur amino acids methionine (Met) and cysteine (Cys) and their derivative taurine (Tau) are metabolically active molecules with interlinked roles in nutritional requirements. Deficiencies in these nutrients are linked to poor growth and health; however, the impacts of these deficiencies on organ structure and function are largely unknown. This study examined the effects of dietary Met, Cys and Tau fed at different levels on yellowtail kingfish (YTK) liver histology and surface colour, plasma biochemistry and posterior intestine histology. Samples were collected from two dose–response feeding trials that quantified (1) the Tau requirement and sparing effect of Met by feeding YTK diets containing one of seven levels of Tau at one of two levels of Met and (2) the Met requirement and sparing effect of Cys by feeding YTK diets containing one of five levels of Met at one of two levels of Cys. YTK fed inadequate levels of dietary Met, Cys and Tau exhibited thicker bile ducts, less red livers, more intestinal acidic goblet cell mucus and supranuclear vacuoles and less posterior intestinal absorptive surface area. Further, thicker bile ducts correlated with less red livers (a*, R), whereas increased hepatic fat correlated with a liver yellowing (b*). Our results indicate a shift towards histological properties and functions indicative of improved intrahepatic biliary condition, posterior intestinal nutrient absorption and homoeostasis of YTK fed adequate amounts of Met, Cys and Tau. These findings may assist in formulating aquafeed for optimised gastrointestinal and liver functions and maintaining good health in YTK
Deprojecting and constraining the vertical thickness of exoKuiper belts
Constraining the vertical and radial structure of debris discs is crucial to
understanding their formation, evolution and dynamics. To measure both the
radial and vertical structure, a disc must be sufficiently inclined. However,
if a disc is too close to edge-on, deprojecting its emission becomes
non-trivial. In this paper we show how Frankenstein, a non-parametric tool to
extract the radial brightness profile of circumstellar discs, can be used to
deproject their emission at any inclination as long as they are optically thin
and axisymmetric. Furthermore, we extend Frankenstein to account for the
vertical thickness of an optically thin disc () and show how it can be
constrained by sampling its posterior probability distribution and assuming a
functional form (e.g. constant ), while fitting the radial profile
non-parametrically. We use this new method to determine the radial and vertical
structure of 16 highly inclined debris discs observed by ALMA. We find a wide
range of vertical aspect ratios, , ranging from (AU Mic) to
(HD 110058), which are consistent with parametric models. We find
a tentative correlation between and the disc fractional width, as expected
if wide discs were more stirred. Assuming discs are self-stirred, the thinnest
discs would require the presence of at least 500 km-sized planetesimals. The
thickest discs would likely require the presence of planets. We also recover
previously inferred and new radial structures, including a potential gap in the
radial distribution of HD 61005. Finally, our new extension of Frankenstein
also allows constraining how varies as a function of radius, which we test
on 49 Ceti, finding that is consistent with being constant.Comment: Accepted for publication in MNRAS. 17 pages. 16 figure
Are there asymmetries in the effects of training on the conditional male wage distribution?
Recent studies have used quantile regression (QR) techniques to estimate the impact of education on the location, scale and shape of the conditional wage distribution. In our paper we investigate the degree to which work-related training – another important form of human capital – affects the location, scale and shape of the conditional wage distribution. Using the first six waves of the European Community Household Panel, we utilise both ordinary least squares and QR techniques to estimate associations between work-related training and wages for private sector men in ten European Union countries. Our results show that, for the majority of countries, there is a fairly uniform association between training and hourly wages across the conditional wage distribution. However, there are considerable differences across countries in mean associations between training and wages
Multi-component physical activity interventions in the UK must consider determinants of activity to increase effectiveness
Interventions to increase physical activity in children have adopted broad approaches and achieved varying success. There is a need to adopt approaches underpinned with a theoretical basis. Accordingly, the aim here was to implement and evaluate a 12-week intervention designed using the concepts of the COM-B model to determine the effect this has on physical activity levels. One hundred and forty-seven school-age children (mean age 8.9 ± 1.3 years) took part in a 12-week program delivered in a school setting. Topics included physical activity, healthy eating, sleep quality and reducing screen time/sedentary activities when not in school. A sample of participants wore a wrist-worn accelerometer for seven days pre-and post-intervention (N = 11). The physical activity frequency was unchanged (2.9 ± 1.0 AU) when compared with post-intervention values (3.1 ± 0.8 AU, mean increase 6.8 ± 3.7%, p > 0.05). Changes were observed in the daily consumption of fruit and vegetables (pre-intervention 44.6% vs. post-intervention 60.2%, p p > 0.05). There is a need to adopt a broader approach that incorporates a theoretical basis and considers the complex ways by which physical activity behaviours are influenced
ALMA 1.3 Millimeter Map of the HD 95086 System
Planets and minor bodies such as asteroids, Kuiper-belt objects and comets
are integral components of a planetary system. Interactions among them leave
clues about the formation process of a planetary system. The signature of such
interactions is most prominent through observations of its debris disk at
millimeter wavelengths where emission is dominated by the population of large
grains that stay close to their parent bodies. Here we present ALMA 1.3 mm
observations of HD 95086, a young early-type star that hosts a directly imaged
giant planet b and a massive debris disk with both asteroid- and Kuiper-belt
analogs. The location of the Kuiper-belt analog is resolved for the first time.
The system can be depicted as a broad (0.84), inclined
(30\arcdeg3\arcdeg) ring with millimeter emission peaked at 2006 au
from the star. The 1.3 mm disk emission is consistent with a broad disk with
sharp boundaries from 1066 to 32020 au with a surface density
distribution described by a power law with an index of --0.50.2. Our deep
ALMA map also reveals a bright source located near the edge of the ring, whose
brightness at 1.3 mm and potential spectral energy distribution are consistent
with it being a luminous star-forming galaxy at high redshift. We set
constraints on the orbital properties of planet b assuming co-planarity with
the observed disk.Comment: accepted for publication in A
Electrical and network neuronal properties are preferentially disrupted in dorsal, but not ventral, medial entorhinal cortex in a mouse model of Tauopathy
The entorhinal cortex (EC) is one of the first areas to be disrupted in neurodegenerative diseases such as Alzheimer's disease and frontotemporal dementia. The responsiveness of individual neurons to electrical and environmental stimuli varies along the dorsal-ventral axis of the medial EC (mEC) in a manner that suggests this topographical organization plays a key role in neural encoding of geometric space. We examined the cellular properties of layer II mEC stellate neurons (mEC-SCs) in rTg4510 mice, a rodent model of neurodegeneration. Dorsoventral gradients in certain intrinsic membrane properties, such as membrane capacitance and afterhyperpolarizations, were flattened in rTg4510 mEC-SCs, while other cellular gradients [e.g., input resistance (Ri), action potential properties] remained intact. Specifically, the intrinsic properties of rTg4510 mEC-SCs in dorsal aspects of the mEC were preferentially affected, such that action potential firing patterns in dorsal mEC-SCs were altered, while those in ventral mEC-SCs were unaffected. We also found that neuronal oscillations in the gamma frequency band (30-80 Hz) were preferentially disrupted in the dorsal mEC of rTg4510 slices, while those in ventral regions were comparatively preserved. These alterations corresponded to a flattened dorsoventral gradient in theta-gamma cross-frequency coupling of local field potentials recorded from the mEC of freely moving rTg4510 mice. These differences were not paralleled by changes to the dorsoventral gradient in parvalbumin staining or neurodegeneration. We propose that the selective disruption to dorsal mECs, and the resultant flattening of certain dorsoventral gradients, may contribute to disturbances in spatial information processing observed in this model of dementia. SIGNIFICANCE STATEMENT: The medial entorhinal cortex (mEC) plays a key role in spatial memory and is one of the first areas to express the pathological features of dementia. Neurons of the mEC are anatomically arranged to express functional dorsoventral gradients in a variety of neuronal properties, including grid cell firing field spacing, which is thought to encode geometric scale. We have investigated the effects of tau pathology on functional dorsoventral gradients in the mEC. Using electrophysiological approaches, we have shown that, in a transgenic mouse model of dementia, the functional properties of the dorsal mEC are preferentially disrupted, resulting in a flattening of some dorsoventral gradients. Our data suggest that neural signals arising in the mEC will have a reduced spatial content in dementia
TLR4 activation induces IL-1ss release via an IPAF dependent but caspase 1/11/8 independent pathway in the lung
Background: The IL-1 family of cytokines is known to play an important role in inflammation therefore understanding the mechanism by which they are produced is paramount. Despite the recent plethora of publications dedicated to the study of these cytokines, the mechanism by which they are produced in the airway following endotoxin, Lipopolysaccharide (LPS), exposure is currently unclear. The aim was to determine the mechanism by which the IL-1 cytokines are produced after LPS inhaled challenge.
Methods:Mice were challenged with aerosolised LPS, and lung tissue and bronchiolar lavage fluid (BALF) collected. Targets were measured at the mRNA and protein level; caspase activity was determined using specific assays.
Results: BALF IL-1b/IL-18, but not IL-1a, was dependent on Ice Protease-Activating Factor (IPAF), and to a lesser extent Apoptosis-associated Speck-like protein containing a CARD (ASC). Interestingly, although we measured an increase in mRNA expression for caspase 1 and 11, we could not detect an increase in lung enzyme activity or a role for them in IL-1a/b production. Further investigations showed that whilst we could detect an increase in caspase 8 activity at later points in the time course (during resolution of inflammation), it appeared to play no role in the production of IL-1 cytokines in this model system.
Conclusions: TLR4 activation increases levels of BALF IL-1b/IL-18 via an IPAF dependent and caspase 1/11/8 independent pathway. Furthermore, it would appear that the presence of IL-1a in the BALF is independent of these pathways. This novel data sheds light on innate signalling pathways in the lung that control the production of these key inflammatory cytokines
Inner edges of planetesimal belts: collisionally eroded or truncated?
The radial structure of debris discs can encode important information about
their dynamical and collisional history. In this paper we present a 3-phase
analytical model to analyse the collisional evolution of solids in debris
discs, focusing on their joint radial and temporal dependence. Consistent with
previous models, we find that as the largest planetesimals reach collisional
equilibrium in the inner regions, the surface density of dust and solids
becomes proportional to within a certain critical radius. We
present simple equations to estimate the critical radius and surface density of
dust as a function of the maximum planetesimal size and initial surface density
in solids (and vice versa). We apply this model to ALMA observations of 7 wide
debris discs. We use both parametric and non-parametric modelling to test if
their inner edges are shallow and consistent with collisional evolution. We
find that 4 out of 7 have inner edges consistent with collisional evolution.
Three of these would require small maximum planetesimal sizes below 10 km, with
HR 8799's disc potentially lacking solids larger than a few centimeters. The
remaining systems have inner edges that are much sharper, which requires
maximum planetesimal sizes km. Their sharp inner edges suggest they
could have been truncated by planets, which JWST could detect. In the context
of our model, we find that the 7 discs require surface densities below a
Minimum Mass Solar Nebula, avoiding the so-called disc mass problem. Finally,
during the modelling of HD 107146 we discover that its wide gap is split into
two narrower ones, which could be due to two low-mass planets formed within the
disc.Comment: Accepted for publication in MNRAS, 21 pages, 11 figure
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