5,349 research outputs found
See no evil, hear no evil, vape no evil; the irresponsible promotion of e-cigarettes and Swaptober
The House of Commons Science and Technology Select Committee have launched an inquiry into e-cigarette impact, implications, and regulation.1 National guidance for improving health should be evidence based, with a complete understanding of what is disseminated and encouraged. However, despite substantial gaps in research, e-cigarettes are promoted as part of smoking cessation efforts, including in the Public Health England (PHE) campaign, One You. Should the suggestion of e-cigarettes as a lesser evil be promoted when evidence of their long-term effect is insufficient
An Upper Limit on the Mass of a Central Black Hole in the Large Magellanic Cloud from the Stellar Rotation Field
We constrain the possible presence of a central black hole (BH) in the center
of the Large Magellanic Cloud (LMC). This requires spectroscopic measurements
over an area of order a square degree, due to the poorly known position of the
kinematic center. Such measurements are now possible with the impressive field
of view of the Multi Unit Spectroscopic Explorer (MUSE) on the ESO Very Large
Telescope. We used the Calcium Triplet (~850nm) spectral lines in many
short-exposure MUSE pointings to create a two-dimensional integrated-light
line-of-sight velocity map from the ~ individual spectra, taking care to
identify and remove Galactic foreground populations. The data reveal a clear
velocity gradient at an unprecedented spatial resolution of 1 arcmin. We
fit kinematic models to arrive at a upper-mass-limit of
M for any central BH - consistent with the known scaling relations for
supermassive black holes and their host systems. This adds to the growing body
of knowledge on the presence of BHs in low-mass and dwarf galaxies, and their
scaling relations with host-galaxy properties, which can shed light on theories
of BH growth and host system interaction.Comment: 12 pages, 11 figures, 1 table, ApJ - in pres
The z<=0.1 Surface Brightness Distribution
The surface brightness distribution (SBD) function describes the number
density of galaxies as measured against their central surface brightness.
Because detecting galaxies with low central surface brightnesses is both
time-consuming and complicated, determining the shape of this distribution
function can be difficult. In a recent paper Cross, et al. suggested a
bell-shaped SBD disk-galaxy function which peaks near the canonical Freeman
value of 21.7 and then falls off significantly by 23.5 B mag arcsec-2. This is
in contradiction to previous studies which have typically found flat (slope=0)
SBD functions out to 24 - 25 B mag arcsec^-2 (the survey limits). Here we take
advantage of a recent surface-brightness limited survey by Andreon & Cuillandre
which reaches considerably fainter magnitudes than the Cross, et.al sample (M_B
reaches fainter than -12 for Andreon & Cuillandre while the Cross, et.al sample
is limited to M_B < -16) to re-evaluate both the SBD function as found by their
data and the SBD for a wide variety of galaxy surveys, including the Cross, et
al. data. The result is a SBD function with a flat slope out through the survey
limits of 24.5 B mag arcsec^-2, with high confidence limits.Comment: 5 pages including 5 figures. accepted by A&A
An Arc of Young Stars in the Halo of M82
The properties of the brightest resolved stars in an arc that was originally
identified by Sun et al. (2005) and is located in the extraplanar regions of
M82 are discussed. The stars form an elongated structure that is traced over a
projected area of 3.0 x 0.8 kpc. The integrated brightness is M_V ~ -11, while
the total stellar mass is between 3 x 10^5 and 2 x 10^6 solar masses. If there
is only foreground extinction then the youngest stars have a metallicity Z >
0.008 and an age log(tyears) ~ 7.75; thus, the youngest stars formed at roughly
the same time as stars in tidal features that are associated with other M81
Group galaxies. If the arc is dispersing then it will deposit young, chemically
enriched stars into the M82 halo.Comment: 11 pages including 3 postscript figures; accepted for publication in
ApJ (Letters
Playing 'Tetris' reduces the strength, frequency and vividness of naturally occurring cravings.
Elaborated Intrusion Theory (EI) postulates that imagery is central to craving, therefore a visually based task should decrease craving and craving imagery. This study provides the first laboratory test of this hypothesis in naturally occurring, rather than artificially induced, cravings. Participants reported if they were experiencing a craving and rated the strength, vividness and intrusiveness of their craving. They then either played 'Tetris' or they waited for a computer program to load (they were told it would load, but it was designed not to). Before task completion, craving scores between conditions did not differ; after, however, participants who had played 'Tetris' had significantly lower craving and less vivid craving imagery. The findings support EI theory, showing that a visuospatial working memory load reduces naturally occurring cravings, and that Tetris might be a useful task for tackling cravings outside the laboratory. Methodologically, the findings show that craving can be studied in the laboratory without using craving induction procedures
Thesaurus as a complex network
A thesaurus is one, out of many, possible representations of term (or word)
connectivity. The terms of a thesaurus are seen as the nodes and their
relationship as the links of a directed graph. The directionality of the links
retains all the thesaurus information and allows the measurement of several
quantities. This has lead to a new term classification according to the
characteristics of the nodes, for example, nodes with no links in, no links
out, etc. Using an electronic available thesaurus we have obtained the incoming
and outgoing link distributions. While the incoming link distribution follows a
stretched exponential function, the lower bound for the outgoing link
distribution has the same envelope of the scientific paper citation
distribution proposed by Albuquerque and Tsallis. However, a better fit is
obtained by simpler function which is the solution of Ricatti's differential
equation. We conjecture that this differential equation is the continuous limit
of a stochastic growth model of the thesaurus network. We also propose a new
manner to arrange a thesaurus using the ``inversion method''.Comment: Contribution to the Proceedings of `Trends and Perspectives in
Extensive and Nonextensive Statistical Mechanics', in honour of Constantino
Tsallis' 60th birthday (submitted Physica A
A multi-beam HI survey of the Virgo Cluster - two isolated HI clouds ?
We have carried out a fully sampled large area ()
21cm \HI line survey of part of the Virgo cluster using the Jodrell Bank
multi-beam instrument. The survey has a sensitivity some 3 times better than
the standard HIJASS and HIPASS surveys. We detect 31 galaxies, 27 of which are
well known cluster members. The four new detections have been confirmed in the
HIPASS data and by follow up Jodrell Bank pointed observations. One object lies
behind M86, but the other 3 have no obvious optical counter parts upon
inspection of the digital sky survey fields. These 3 objects were mapped at
Arecibo with a smaller \am{3}{6} HPBW and a 4 times better sensitivity than the
Jodrell Bank data, which allow an improved determination of the dimensions and
location of two of the objects, but surprisingly failed to detect the third.
The two objects are resolved by the Arecibo beam giving them a size far larger
than any optical images in the nearby field. To our mass limit of and column density limit of
atoms cm these new
detections represent only about 2% of the cluster atomic hydrogen mass. Our
observations indicate that the \HI mass function of the cluster turns down at
the low mass end making it very different to the field galaxy \HI mass
function. This is quite different to the Virgo cluster optical luminosity
function which is much steeper than that in the general field. Many of the
sample galaxies are relatively gas poor compared to \HI selected samples of
field galaxies, confirming the 'anaemic spirals' view of Virgo cluster late
type galaxies.Comment: Accepted for publication in MNRA
Radiographic classification of coronal plane femoral deformities in polyostotic fibrous dysplasia
Fibrous dysplasia of bone is a skeletal dysplasia with a propensity to affect the femur in its polyostotic form, leading to deformity, fracture, and pain. The proximal femur is most commonly involved with a tendency to distal progression, thereby producing the typical shepherd's crook deformity. However, there are few data on the spectrum and progression of femoral deformities in polyostotic fibrous dysplasia
Variable maternal nutrition and growth hormone treatment in the second quarter of pregnancy in pigs alter semitendinosus muscle in adolescent progeny
Maternal nutrition and growth hormone (GH) treatment during early- to mid-pregnancy can each alter the subsequent growth and differentiation of muscle in progeny. We have investigated the effects of varying maternal nutrition and maternal treatment with porcine (p) GH during the second quarter of pregnancy in gilts on semitendinosus muscle cross-sectional area and fibre composition of progeny, and relationships between maternal and progeny measures and progeny muscularity. Fifty-three Large WhiteĂLandrace gilts, pregnant to Large WhiteĂDuroc boars, were fed either 2·2 kg (about 35 % ad libitum intake) or 3·0 kg commercial ration (13·5 MJ digestible energy, 150 g crude protein (NĂ6·25)/kg DM)/d and injected with 0, 4 or 8 mg pGH/d from day 25 to 50 of pregnancy, then all were fed 2·2 kg/d for the remainder of pregnancy. The higher maternal feed allowance from day 25 to 50 of pregnancy increased the densities of total and secondary fibres and the secondary:primary fibre ratio in semitendinosus muscles of their female progeny at 61 d of age postnatally. The densities of secondary and total muscle fibres in semitendinosus muscles of progeny were predicted by maternal weight before treatment and maternal plasma insulin-like growth factor-II during treatment. Maternal pGH treatment from day 25 to day 50 of pregnancy did not alter fibre densities, but increased the cross-sectional area of the semitendinosus muscle; this may be partially explained by increased maternal plasma glucose. Thus, maternal nutrition and pGH treatment during the second quarter of pregnancy in pigs independently alter muscle characteristics in progeny.Kathryn L. Gatford, Jason E. Ekert, Karina Blackmore, Miles J. De Blasio, Jodie M. Boyce, Julie A. Owens, Roger G. Campbell and Phillip C. Owen
AFRP20: New P-Wavespeed Model for the African Mantle Reveals Two Whole-Mantle Plumes Below East Africa and Neoproterozoic Modification of the Tanzania Craton
Africaâs Cenozoic tectonism is often attributed to mantle plumes, particularly below East Africa, but their morphology, number, location, and impact on the African lithosphere are debated. The broad slow wavespeed African Superplume, ubiquitous in large-scale tomographic models, originates below South Africa, reaching the surface somewhere below East Africa. However, whether the diverse East African mantle geochemistry is best reconciled with one heterogeneous upwelling, or current tomographic models lack the resolution to image multiple distinct plumes, remains enigmatic. S-wavespeed tomographic images of Africa are legion, but higher-frequency P-wavespeed whole-mantle models possessing complementary diagnostic capabilities are comparatively lacking. This hinders attempts to disentangle the effects of Cenozoic hotspot tectonism and Pan African (and older) tectonic events on the East African lithosphere. Here we develop a continental-scale P-wave tomographic model capable of resolving structure from upper-to-lower mantle depths using a recently-developed technique to extract absolute arrival-times from noisy, temporary African seismograph deployments. Shallow-mantle wavespeeds are ÎŽVP ââ4% below Ethiopia, but less anomalous (ÎŽVP â„â2%) below other volcanic provinces. The heterogeneous African Superplume reaches the upper mantle below the Kenyan plateau. Below Ethiopia/Afar we image a second sub-vertical slow wavespeed anomaly rooted near the core-mantle boundary outside the African LLVP, meaning multiple disparately sourced whole-mantle plumes may influence East African magmatism. In contrast to other African cratons, wavespeeds below Tanzania are only fast to 90â135km depth. When interpreted alongside Lower Eocene on-craton kimberlites, our results support pervasive metasomatic lithospheric modification caused by subduction during the Neoproterozoic Pan-African orogeny.A. B. and S. C. are funded by the Natural Environment Research Council (NERC) Grant number NE/R010862/1 from PI Cottaar in Cambridge. A. B. was previously funded by the NERC Doctoral Training Partnership: Science and Solutions for a Changing Planet - Grant number NE/L002515/1 at Imperial College. I. B is funded by Natural Environment Research Council Grant number NE/S014136/1
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