6,979 research outputs found
Superorbital Period in the High Mass X-ray Binary 2S 0114+650
We report the detection of a superorbital period in the high-mass X-ray
binary 2S 0114+650. Analyses of data from the Rossi X-ray Timing Explorer
(RXTE) All-Sky Monitor (ASM) from 1996 January 5 to 2004 August 25 reveal a
superorbital period of 30.7 +/- 0.1 d, in addition to confirming the previously
reported neutron star spin period of 2.7 h and the binary orbital period of
11.6 d. It is unclear if the superorbital period can be ascribed to the
precession of a warped accretion disc in the system.Comment: 5 pages, 5 figures, submitted to MNRAS 27th January 2005. Manuscript
expanded to include discussion of evolution of periods, and hardness ratio
variability. Number of figures increased from 5 to 9. Accepted for
publication 19th December 200
A Multicoloured View of 2S 0114+650
We report the results of radio and X-ray observations of the high mass X-ray
binary 2S 0114+650, made with the Giant Meterwave Radio Telescope and the Rossi
X-ray Timing Explorer respectively. No emission was detected at radio
wavelengths. The neutral hydrogen column density was found to vary over the
orbital period, while no variability over the the super-orbital period was
observed. We discuss the causes of the observed relationships and the
implications for the underlying mechanisms.Comment: 4 pages, 2 figures; to appear in proceedings for "The multicoloured
landscape of compact objects and their explosive progenitors", Cefalu,
Sicily, 2006 June 11-24, AIP, submitte
Demography and disorders of the French Bulldog population under primary veterinary care in the UK in 2013
Abstract Background Despite its Gallic name, the French Bulldog is a breed of both British and French origin that was first recognised by The Kennel Club in 1906. The French Bulldog has demonstrated recent rapid rises in Kennel Club registrations and is now (2017) the second most commonly registered pedigree breed in the UK. However, the breed has been reported to be predisposed to several disorders including ocular, respiratory, neurological and dermatological problems. The VetCompassâą Programme collates de-identified clinical data from primary-care veterinary practices in the UK for epidemiological research. Using VetCompassâą clinical data, this study aimed to characterise the demography and common disorders of the general population of French Bulldogs under veterinary care in the UK. Results French Bulldogs comprised 2228 (0.49%) of 445,557 study dogs under veterinary care during 2013. Annual proportional birth rates showed that the proportional ownership of French Bulldog puppies rose steeply from 0.02% of the annual birth cohort attending VetCompassâą practices in 2003 to 1.46% in 2013. The median age of the French Bulldogs overall was 1.3 years (IQR 0.6â2.5, range 0.0â13.0). The most common colours of French Bulldogs were brindle (solid or main) (32.36%) and fawn (solid or main) (29.9%). Of the 2228 French Bulldogs under veterinary care during 2013, 1612 (72.4%) had at least one disorder recorded. The most prevalent fine-level precision disorders recorded were otitis externa (14.0%, 95% CI: 12.6â15.5), diarrhoea (7.5%, 95% CI: 6.4â8.7), conjunctivitis (3.2%, 95% CI: 2.5â4.0), nails overlong (3.1%, 95% CI% 2.4â3.9) and skin fold dermatitis (3.0%, 95% CI% 2.3â3.8). The most prevalent disorder groups were cutaneous (17.9%, 95% CI: 16.3â19.6), enteropathy (16.7%, 95% CI: 15.2â18.3), aural (16.3%, 95% CI: 14.8â17.9), upper respiratory tract (12.7%, 95% CI: 11.3â14.1) and ophthalmological (10.5%, 95% CI: 9.3â11.9). Conclusions Ownership of French Bulldogs in the UK is rising steeply. This means that the disorder profiles reported in this study reflect a current young UK population and are likely to shift as this cohort ages. Otitis externa, diarrhoea and conjunctivitis were the most common disorders in French Bulldogs. Identification of health priorities based on VetCompassâą data can support evidenceâbased reforms to improve health and welfare within the breed
Topological Properties from Einstein's Equations?
In this work we propose a new procedure for to extract global information of
a space-time. We considered a space-time immersed in a higher dimensional space
and we formulate the equations of Einstein through of the Frobenius conditions
to immersion. Through of an algorithm and the implementation into algebraic
computing system we calculate normal vectors from the immersion to find out the
second fundamental form. We make a application for space-time with spherical
symmetry and static. We solve the equations of Einstein to the vacuum and we
obtain space-times with different topologies.Comment: 7 pages, accepted for publication in Int. J. Mod. Phys.
No time machines in classical general relativity
Irrespective of local conditions imposed on the metric, any extendible
spacetime U has a maximal extension containing no closed causal curves outside
the chronological past of U. We prove this fact and interpret it as
impossibility (in classical general relativity) of the time machines, insofar
as the latter are defined to be causality-violating regions created by human
beings (as opposed to those appearing spontaneously).Comment: A corrigendum (to be published in CQG) has been added to correct an
important mistake in the definition of localit
Perfect fluids from high power sigma-models
Certain solutions of a sextic sigma-model Lagrangian reminiscent of Skyrme
model correspond to perfect fluids with stiff matter equation of state. We
analyse from a differential geometric perspective this correspondence extended
to general barotropic fluids.Comment: 17 pages. Version published in IJGMMP 8 (2011). Added Example 3.4 and
1 referenc
Prevalence and risk factors for mast cell tumours in dogs in England
BACKGROUND: Mast cell tumour (MCT) appears to be a frequent tumour type in dogs, though there is little published in relation to its frequency in dogs in the UK. The current study aimed to investigate prevalence and risk factors for MCTs in dogs attending English primary-care veterinary practices. METHODS: Electronic patient records from practices participating in the VetCompass animal surveillance project between July 2007 and June 2013 were searched for MCT diagnosis. Various search terms and standard diagnostic terms (VeNom codes) identified records containing MCT diagnoses, which were evaluated against clinical criteria for inclusion to the study. MCT prevalence for the entire dataset and specific breed types were calculated. Descriptive statistics characterised MCT cases and multivariable logistic regression methods evaluated risk factors for association with MCT (Pâ<â0.05). RESULTS: Within a population of 168,636 dogs, 453 had MCT, yielding a prevalence of 0.27% (95% confidence interval (CI) 0.24% - 0.29%). The highest breed type specific prevalences were for the Boxer at 1.95% (95% CI 1.40% - 2.51%), Golden Retriever at 1.39% (0.98% - 1.81%) and Weimaraner at 0.85% (95% CI 0.17% to 1.53%). Age, insurance status, neuter status, weight and breed type were associated with MCT diagnosis. Of dogs of specific breed type, the Boxer, Pug and Staffordshire Bull Terrier showed greater odds of MCT diagnosis compared with crossbred dogs. Conversely, the German Shepherd Dog, Border Collie, West Highland White Terrier, Springer Spaniel and Cocker Spaniel had reduced odds of MCT diagnosis compared with crossbred dogs. No association was found between MCT diagnosis and sex. CLINICAL SIGNIFICANCE: This study highlights a clinically significant prevalence of MCT and identifies specific breed types with predisposition to MCT, potentially aiding veterinarian awareness and facilitating diagnosis
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