Plasma discharges with a negative triangularity (δ=-0.4) shape have been created in the DIII-D tokamak with a significant normalized beta (β_{N}=2.7) and confinement characteristic of the high ...confinement mode (H_{98y2}=1.2) despite the absence of an edge pressure pedestal and no edge localized modes (ELMs). These inner-wall-limited plasmas have a similar global performance as a positive triangularity (δ=+0.4) ELMing H-mode discharge with the same plasma current, elongation and cross sectional area. For cases both of dominant electron cyclotron heating with T_{e}/T_{i}>1 and dominant neutral beam injection heating with T_{e}/T_{i}=1, turbulent fluctuations over radii 0.5<ρ<0.9 were reduced by 10-50% in the negative triangularity shape compared to the matching positive triangularity shape, depending on the radius and conditions.
Considerable ambiguity remains over the extent and nature of millennial/centennial-scale climate instability during the Last Interglacial (LIG). Here we analyse marine and terrestrial proxies from a ...deep-sea sediment sequence on the Portuguese Margin and combine results with an intensively dated Italian speleothem record and climate-model experiments. The strongest expression of climate variability occurred during the transitions into and out of the LIG. Our records also document a series of multi-centennial intra-interglacial arid events in southern Europe, coherent with cold water-mass expansions in the North Atlantic. The spatial and temporal fingerprints of these changes indicate a reorganization of ocean surface circulation, consistent with low-intensity disruptions of the Atlantic meridional overturning circulation (AMOC). The amplitude of this LIG variability is greater than that observed in Holocene records. Episodic Greenland ice melt and runoff as a result of excess warmth may have contributed to AMOC weakening and increased climate instability throughout the LIG.
ABSTRACT
We present high-cadence multifrequency radio observations of the long gamma-ray burst (GRB) 190829A, which was detected at photon energies above 100 GeV by the High Energy Stereoscopic ...System (H.E.S.S.). Observations with the Meer Karoo Array Telescope (MeerKAT, 1.3 GHz) and Arcminute Microkelvin Imager – Large Array (AMI-LA, 15.5 GHz) began one day post-burst and lasted nearly 200 d. We used complementary data from Swift X-Ray Telescope (XRT), which ran to 100 d post-burst. We detected a likely forward shock component with both MeerKAT and XRT up to over 100 d post-burst. Conversely, the AMI-LA light curve appears to be dominated by reverse shock emission until around 70 d post-burst when the afterglow flux drops below the level of the host galaxy. We also present previously unpublished observations of the other H.E.S.S.-detected GRB, GRB 180720B from AMI-LA, which shows likely forward shock emission that fades in less than 10 d. We present a comparison between the radio emission from the three GRBs with detected very high energy (VHE) gamma-ray emission and a sensitivity-limited radio afterglow sample. GRB 190829A has the lowest isotropic radio luminosity of any GRB in our sample, but the distribution of luminosities is otherwise consistent, as expected, with the VHE GRBs being drawn from the same parent distribution as the other radio-detected long GRBs.
Highlights ► Male C57BL/6J mice were singly housed under four conditions for 32 days: standard, EE, run, or both. ► Novel toys and treats were rotated into the enrichment conditions every 4 days. ► ...Animals in the run group displayed increased neurogenesis and enhanced water maze performance. ► Mere interaction with a stimulating environment does not confer neurogenic or cognitive benefits.
The intrinsic electrical properties of neurons are shaped in large part by the action of voltage-gated ion channels. Molecular cloning studies have revealed a large family of ion channel genes, many ...of which are expressed in mammalian brain. Much recent effort has focused on determining the contribution of the protein products of these genes to neuronal function. This requires knowledge of the abundance and distribution of the constituent subunits of the channels in specific mammalian central neurons. Here we review progress made in recent studies aimed at localizing specific ion channel subunits using in situ hybridization and immunohistochemistry. We then discuss the implications of these results in terms of neuronal physiology and neuronal mechanisms underlying the observed patterns of expression.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Summary
Background Vitamin D is necessary for bone health and is potentially protective against a range of malignancies. Opinions are divided on whether the proposed optimal circulating ...25‐hydroxyvitamin D 25(OH)D level (≥ 32 ng mL−1) is an appropriate and feasible target at population level.
Objectives We examined whether personal sunlight exposure levels can provide vitamin D sufficient (≥ 20 ng mL−1) and optimal status in the U.K. public.
Methods This prospective cohort study measured circulating 25(OH)D monthly for 12 months in 125 white adults aged 20–60 years in Greater Manchester. Dietary vitamin D and personal ultraviolet radiation (UVR) exposure were assessed over 1–2 weeks in each season. The primary analysis determined the post‐summer peak 25(OH)D required to maintain sufficiency in wintertime.
Results Dietary vitamin D remained low in all seasons (median 3·27 μg daily, range 2·76–4·15) while personal UVR exposure levels were high in spring and summer, low in autumn and negligible in winter. Mean 25(OH)D levels were highest in September 28·4 ng mL−1; 28% optimal, zero deficient (<5 ng mL−1), and lowest in February (18·3 ng mL−1; 7% optimal, 5% deficient). A February 25(OH)D level of 20 ng mL−1 was achieved following a mean (95% confidence interval) late summer level of 30·4 (25·6–35·2) and 34·9 (27·9–41·9) ng mL−1 in women and men, respectively, with 62% of variance explained by gender and September levels.
Conclusions Late summer 25(OH)D levels approximating the optimal range are required to retain sufficiency throughout the U.K. winter. Currently the majority of the population fails to reach this post‐summer level and becomes vitamin D insufficient during the winter.
ABSTRACT
We investigate if the discrepancy between estimates of the total baryon mass fraction obtained from observations of the cosmic microwave background (CMB) and of galaxy groups/clusters ...persists when a large sample of groups is considered. To this purpose, 91 candidate X-ray groups/poor clusters at redshift 0.1 ⩽
z
⩽ 1 are selected from the COSMOS 2 deg
2
survey, based only on their X-ray luminosity and extent. This sample is complemented by 27 nearby clusters with a robust, analogous determination of the total and stellar mass inside
R
500
. The total sample of 118 groups and clusters with
z
⩽ 1 spans a range in
M
500
of ∼10
13
–10
15
M
☉
. We find that the stellar mass fraction associated with galaxies at
R
500
decreases with increasing total mass as
M
−0.37 ± 0.04
500
, independent of redshift. Estimating the total gas mass fraction from a recently derived, high-quality scaling relation, the total baryon mass fraction (
f
stars+gas
500
=
f
stars
500
+
f
gas
500
) is found to increase by ∼25%, when
M
500
increases from 〈
M
〉 = 5 × 10
13
M
☉
to 〈
M
〉 = 7 × 10
14
M
☉
. After consideration of a plausible contribution due to intracluster light (11%–22% of the total stellar mass) and gas depletion through the hierarchical assembly process (10% of the gas mass), the estimated values of the total baryon mass fraction are still lower than the latest CMB measure of the same quantity (WMAP5), at a significance level of 3.3σ for groups of 〈
M
〉 = 5 × 10
13
M
☉
. The discrepancy decreases toward higher total masses, such that it is 1σ at 〈
M
〉 = 7 × 10
14
M
☉
. We discuss this result in terms of nongravitational processes such as feedback and filamentary heating.
ABSTRACT
We present the results of a radio observing campaign on GRB 201216C, combined with publicly available optical and X-ray data. The detection of very high energy (VHE, >100 GeV) emission by ...MAGIC makes this the fifth VHE GRB at the time of publication. Comparison between the optical and X-ray light curves show that GRB 201216C is a dark GRB, i.e. the optical emission is significantly absorbed and is fainter than expected from the X-ray detections. Our e-MERLIN data also shows evidence of diffractive interstellar scintillation. We can study the column density along the line of sight to the GRB in both the host galaxy, from the damped optical light curve, and the Milky Way, via scintillation studies. We find that the afterglow is best modelled using a jet-cocoon geometry within a stellar wind environment. Fitting the data with a multicomponent model, we estimate that the optical, X-ray, and higher frequency radio data before ∼25 d originates from an ultrarelativistic jet with an isotropic equivalent kinetic energy of (0.6–10) × 1052 erg and an opening angle of ∼1–9°. The lower frequency radio emission detected by MeerKAT, from day 28 onwards, is produced by the cocoon with a kinetic energy that is between two and seven orders of magnitude lower (0.02–50) × 1048 erg. The energies of the two components are comparable to those derived in simulations of such scenarios.
In addition to N-terminal pro-brain natriuretic peptide (NT-proBNP), red cell distribution width (RDW), growth differentiation factor (GDF)-15, interleukin (IL)-6 and creatinine are all potential ...circulating prognostic biomarkers in pulmonary arterial hypertension (PAH).
To establish the relative prognostic utility of these biomarkers in patients with idiopathic PAH (IPAH) and to identify independent prognostic markers in this disease.
Circulating RDW, GDF-15, IL-6, creatinine and NT-proBNP levels were determined in 139 patients with IPAH (mean follow-up 4.0±2.4 years) and 40 age- and sex-matched healthy volunteers. Coincident clinical data and baseline haemodynamic measurements were also analysed.
All the biomarkers except creatinine correlated with a 6 min walk distance (6MWD; p<0.05), and all but NT-proBNP correlated with WHO functional class (p<0.01). GDF-15, creatinine and NT-proBNP correlated with mean right atrial pressures and cardiac index. RDW outperformed other biomarkers in receiver operating characteristic (ROC) analysis (area under the curve 0.820). Sensitive (>80%) ROC-derived cut-off points of RDW (15.7%, p=0.001), GDF-15 (779 pg/ml, p<0.001), IL-6 (2.5 pg/ml, p=0.019), creatinine (80.5 μmol/l, p=0.010) and NT-proBNP (491 fmol/ml, p<0.001), all predicted survival in patients with IPAH over time. All the plasma biomarkers analysed predicted survival in Cox regression analysis, as did clinical and haemodynamic parameters. However, only RDW predicted survival independently of NT-proBNP and 6MWD.
Circulating RDW, GDF-15, IL-6, creatinine and NT-proBNP levels are all related to disease severity and may be used to predict survival in patients with IPAH. RDW added significant prognostic value to measurements of NT-proBNP and exercise capacity and may prove valuable in a multiple biomarker approach to disease stratification.
It is important to decipher the diversity and distribution of benthic dinoflagellates, as there are many morphologically indistinct taxa that differ from one another in production of potent toxins. ...To date, the genus Ostreopsis comprises twelve described species, of which seven are potentially toxic and produce compounds presenting a threat to human and environmental health. In this study, isolates previously identified as "Ostreopsis sp. 3" were sampled from the area where it was first reported, Rarotonga, Cook Islands, and have been taxonomically and phylogenetically characterised as Ostreopsis tairoto sp. nov. Phylogenetically, the species is closely related to "Ostreopsis sp. 8", O. mascarenensis, "O. sp. 4", O. fattorussoi, O. rhodesiae and O. cf. siamensis. Previously, it was considered a part of the O. cf. ovata complex but can be distinguished from O. cf. ovata based on the small pores identified on this study, and from O. fattorussoi and O. rhodesiae based on relative lengths of the 2' plates. No known palytoxin -like compounds were detected in strains investigated in this study. Strains of O. lenticularis, Coolia malayensis and C. tropicalis were also identified and described. This study advances our knowledge of biogeography, distribution, and toxins of Ostreopsis and Coolia species.
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