515 research outputs found
An Eccentric Eclipsing Binary: CGAur
In this study, we present CG Aur's photometric observations obtained in the
observing seasons 2011 and 2012, the first available multi-colour light curves.
Their shape indicates that the system is an Algol binary. The light curve
analyses reveal that CG Aur is a detached binary system with an effective
temperature difference between the components, approximately 1000 K. The first
estimate of the absolute dimensions of the components indicated that the system
locates on the main sequence in the HR diagram. The primary component is
slightly evolved from the ZAMS.Comment: 18 pages, 6 figures, 3 table
A New Baseline for Diadema antillarum, Echinometra viridis, E. lucunter, and Eucidaris tribuloides Populations Within the Cayos Cochinos MPA, Honduras
We investigated the density of 4 urchin species from 5 shallow reefs in the Cayos Cochinos Marine Protected Area in Honduras. Individual species density varied among reefs with total urchin density ranging from 3.2â7.9 individuals/m2. Echinometra viridis (Agassiz, 1863) was the numerically dominant species (2.29/m2) followed by E. lucunter (Linnaeus, 1758) (1.76/m2) with Eucidaris tribuloides (Lamarck 1816) representing the fewest individuals (0.42/m2). Our results indicated that density of Diadema antillarum (Philippi, 1845) differed significantly among reefs (0.4-1.3/m2, mean = 0.63/m2), but are three times greater than data collected 12 years after the mass mortality event of the 1980âs. Size frequency analysis of D. antillarum indicated that test diameter also differed significantly among reef sites while correlation analysis showed that D. antillarum density was negatively related to both coral and algal cover. Echinometra viridis density, however, was positively related to coral cover (p \u3c 0.05). When all urchins were combined, they showed a negative correlation with algal cover and a positive correlation with coral cover indicating a potential top-down effect within the reefs. While urchin densities remain relatively low compared to other sites in the Caribbean, the D. antillarum population appears to be recovering in this Honduran MPA. If overall grazer abundance continues to increase then they may limit macroalgae on reefs, thereby encouraging coral settlement
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Comparing non-invasive surveying techniques for elusive, nocturnal mammals: a case study of the West European hedgehog (Erinaceus europaeus)
Monitoring changes in populations is fundamental for effective management. The West European
hedgehog (Erinaceus europeaus) is of conservation concern in the UK because of recent substantial declines.
Surveying hedgehogs is, however, problematic because of their nocturnal, cryptic behaviour. We compared
the effectiveness of three methods (infra-red thermal camera, specialist search dog, spotlight) for detecting
hedgehogs in three different habitats. Significantly more hedgehogs were detected, and at greater distance,
using the camera and dog than the spotlight in amenity grassland and pasture; no hedgehogs were detected
in woodland. Increasing ground cover reduced detection distances, with most detections (59.6%) associated
with bare soil or mown grass; the dog was the only method that detected hedgehogs in vegetation taller than
the target speciesâ height. The additional value of surveying with a detection dog is most likely to be realised in
areas where badgers (Meles meles), an intra-guild predator, are and/or where sufficient ground cover is present;
both would allow hedgehogs to forage further from refuge habitats such as hedgerows. Further consideration
of the effectiveness of detection dogs for finding hedgehogs in nests, as well as developing techniques for
monitoring this species in woodland, is warranted
Photometric Analysis of Recently Discovered Eclipsing Binary GSC 00008-00901
Photometric analysis of light curves of newly discovered eclipsing
binary GSC 0008-00901 is presented. The orbital period is improved to
0.28948(11) days. Photometric parameters are determined, as well. The analysis
yielded to conclusion that system is an over-contact binary of W UMa type with
components not in thermal contact. The light curves from 2005 show the presence
of a spot on the surface of one of the components, while light curves from 2006
are not affected by maculation.Comment: Accepted for publication in Astrophysics & Space Scienc
Photometric and spectroscopic observations of the F3+M3 eclipsing binary T-Lyr0-08070
The multi-color photometric and spectroscopic observations of the newly
discovered eclipsing binary T-Lyr0-08070 were obtained. The resultant light and
radial velocities were analysed and the absolute parameters of the components
were determined. The system is composed of an F3 and an M3 main-sequence stars.
Masses and radii were estimated to be 1.370.23 M and
1.600.09 R for the primary and 0.320.04 M and
0.860.06R for the secondary star. The less massive secondary
component has a radius at least two times larger with respect to its mass.
Using the BVJHK magnitudes of the system we estimated an interstellar reddening
of 0.22 mag and a distance to the system as 47936 pc.Comment: Accepted. 21 pages, 7 figures; 2012, Sept.New.Ast. arXiv admin note:
text overlap with arXiv:0909.1921, arXiv:1007.513
External evaluation of the Represent programme: report for the National Literacy Trust
NLTâs Represent programme aimed to address the comparatively lower chances of educational achievement of excluded girls and their greater vulnerability to exploitation, grooming, violence, or engaging in criminal behaviour. Excluded girls often have chaotic lives, live in poverty and are less likely to have access to professionals that might provide the stability and support required for sustained engagement with positive role models1. In total, 265 education settings registered their interest in delivering the Represent programme with NLT and received the resource pack required for delivering sessions for 368 groups of students. Of these, at least 822 schools participated in one or more aspects of the evaluation project. The evaluation of the Represent programme sets out to understand five key questions using a mixed-methods approach to explore the complexities of the girlsâ experiences, and how the programme has helped to connect the problems around attendance with pathways to future capabilities and wellbeing
Cardiovascular disease in transgendered people: A review of the literature and discussion of risk.
This review examines the impact of gender affirming hormone therapy used in the transgendered and non-binary populations on cardiovascular outcomes and surrogate markers of cardiovascular health. Current evidence suggests that hormonal therapy for transgendered women decreases or is neutral regarding myocardial infarction risk. There is an increased incidence of venous thromboembolism (VTE), but newer studies suggest that the risk is significantly lower than previously described. For transgendered men, there appears to be an adverse effect on lipid parameters but this does not translate into an increased risk of cardiovascular disease above that of general male population. In all transgendered people, risk factor interventions such as smoking cessation, weight management and treatment of co-morbid conditions are important in optimising cardiovascular health. The effect of gender affirming hormonal therapy in transgendered people is difficult to interpret due to the variety of hormone regimens used, the relative brevity of the periods of observation and the influence of confounding factors such as the historical use of less physiological, oestrogens such as conjugated equine oestrogen and ethinylestradiol which are more pro-thrombotic than the 17ÎČ oestradiol that is used in modern practice
Rotational velocities of A-type stars. III. Velocity distributions
Aim - In this work, a sample of vsini of B9 to F2-type main sequence single
stars has been built from highly homogeneous vsini parameters determined for a
large sample cleansed from objects presenting the Am and Ap phenomenon as well
as from all known binaries. The aim is to study the distributions of rotational
velocities in the mass range of A-type stars for normal single objects.
Methods - Robust statistical methods are used to rectify the vsini
distributions from the projection effect and the error distribution. The
equatorial velocity distributions are obtained for an amount of about 1100
stars divided in six groups defined by the spectral type, under the assumption
of randomly orientated rotational axes.
Results - We show that late B and early A-type main-sequence stars have
genuine bimodal distributions of true equatorial rotational velocities due
probably to phenomena of angular momentum loss and redistribution the star
underwent before reaching the main sequence. A striking lack of slow rotators
is noticed among intermediate and late A-type stars. The bimodal-like shape of
their true equatorial rotational velocity distributions could be due to
evolutionary effects.Comment: 16 pages, 10 figures, accepted in A&
Centrosome dysfunction associated with somatic expression of the synaptonemal complex protein TEX12
The synaptonemal complex (SC) is a supramolecular protein scaffold that mediates chromosome synapsis and facilitates crossing over during meiosis. In mammals, SC proteins are generally assumed to have no other function. Here, we show that SC protein TEX12 also localises to centrosomes during meiosis independently of chromosome synapsis. In somatic cells, ectopically expressed TEX12 similarly localises to centrosomes, where it is associated with centrosome amplification, a pathology correlated with cancer development. Indeed, TEX12 is identified as a cancer-testis antigen and proliferation of some cancer cells is TEX12-dependent. Moreover, somatic expression of TEX12 is aberrantly activated via retinoic acid signalling, which is commonly disregulated in cancer. Structure-function analysis reveals that phosphorylation of TEX12 on tyrosine 48 is important for centrosome amplification but not for recruitment of TEX12 to centrosomes. We conclude that TEX12 normally localises to meiotic centrosomes, but its misexpression in somatic cells can contribute to pathological amplification and dysfunction of centrosomes in cancers
Reanalysis of two eclipsing binaries: EE Aqr and Z Vul
We study the radial-velocity and light curves of the two eclipsing binaries
EE Aqr and Z Vul. Using the latest version of the Wilson & Van Hamme (2003)
model, absolute parameters for the systems are determined. We find that EE Aqr
and Z Vul are near-contact and semi-detached systems, respectively. The primary
component of EE Aqr fills about 96% of its 'Roche lobe', while its secondary
one appears close to completely filling this limiting volume. In a similar way,
we find fill-out proportions of about 72 and 100% of these volumes for the
primary and secondary components of Z Vul respectively. We compare our results
with those of previous authors.Comment: 13 pages, 8 figures, 10 table
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