A note on behaviour at an isotropic singularity

The behaviour of Jacobi fields along a time-like geodesic running into an isotropic singularity is studied. It is shown that the Jacobi fields are crushed to zero length at a rate which is the same in every direction orthogonal to the geodesic. We show by means of a counter-example that this crushing effect depends crucially on a technicality of the definition of isotropic singularities, and not just on the uniform degeneracy of the metric at the singularity.Comment: 13 pp. plain latex. To appear in Classical and Quantum Gravit

Pengaruh Kualitas Ransum Dna Temperatur Lingkungan

Penelitian untuk mengetahui pengaruh ransum dan suhu lingkungan terhadap karakteristik karkas dan daging telah dilakukan dengan menggunakan 16 ekor domba persilangan Border Leicester x Merino jantan kastrasi, umur 7 bulan, bobot 33.0+1.49 kg. Domba-bomba tersebut dialokasikan secara acak pada perlakuan dalam rancangan acak kelompok dengan struktur faktorial 2 x 2. Perlakuan yang diterapkan adalah suhu lingkungan (20° and 30°C) dan ransum (RPTS: rendah protein tinggi serat, dan TPRS: tinggi protein rendah serat). Ransum TPRS memberikan hasil persentase karkas dan ketebalan lemak punggung yang lebih tinggi daripada ransum RPTS (49.7 vs 44.4 % dan 14.2 vs 6.8 mm berturutan), tetapi tidak terdapat pengaruh nyata suhu terhadap karakteristik karkas. Terdapat interaksi nyata antara suhu dan ransum pada otot mata rusuk. Pada domba yang mendapat ransum RPTS, suhu berpengaruh nyata, sementara pada domba yang mendapat TPRS, suhu tidak berpengaruh nyata. Daging domba yang diberi RPTS mempunyai rasa yang lebih enak daripada domba yang dib,_.i TPRS. Suhu tidak berpengaruh nyata terhadap aroma daging. Baik suhu maupun ransum tidak berpengaruh nyata pada pH, warna maupun keempukan daging. (Kata kunci: Domba jantan kastrasi, Cekaman panas, Karkas, Daging)

Patient reactions to a web-based cardiovascular risk calculator in type 2 diabetes: a qualitative study in primary care.

Use of risk calculators for specific diseases is increasing, with an underlying assumption that they promote risk reduction as users become better informed and motivated to take preventive action. Empirical data to support this are, however, sparse and contradictory

On the existence of dyons and dyonic black holes in Einstein-Yang-Mills theory

We study dyonic soliton and black hole solutions of the ${\mathfrak {su}}(2)$ Einstein-Yang-Mills equations in asymptotically anti-de Sitter space. We prove the existence of non-trivial dyonic soliton and black hole solutions in a neighbourhood of the trivial solution. For these solutions the magnetic gauge field function has no zeros and we conjecture that at least some of these non-trivial solutions will be stable. The global existence proof uses local existence results and a non-linear perturbation argument based on the (Banach space) implicit function theorem.Comment: 23 pages, 2 figures. Minor revisions; references adde

General properties of cosmological models with an Isotropic Singularity

Much of the published work regarding the Isotropic Singularity is performed under the assumption that the matter source for the cosmological model is a barotropic perfect fluid, or even a perfect fluid with a $\gamma$-law equation of state. There are, however, some general properties of cosmological models which admit an Isotropic Singularity, irrespective of the matter source. In particular, we show that the Isotropic Singularity is a point-like singularity and that vacuum space-times cannot admit an Isotropic Singularity. The relationships between the Isotropic Singularity, and the energy conditions, and the Hubble parameter is explored. A review of work by the authors, regarding the Isotropic Singularity, is presented.Comment: 18 pages, 1 figur

A Characterisation of Strong Wave Tails in Curved Space-Times

A characterisation of when wave tails are strong is proposed. The existence of a curvature induced tail (i.e. a Green's function term whose support includes the interior of the light-cone) is commonly understood to cause backscattering of the field governed by the relevant wave equation. Strong tails are characterised as those for which the purely radiative part of the field is backscattered. With this definition, it is shown that electromagnetic waves in asymptotically flat space-times and fields governed by tail-free propagation have weak tails, but minimally coupled scalar fields in a cosmological scenario have strong tails.Comment: 17 pages, Revtex, to appear in Classical and Quantum Gravit

The Effect of Quality of Diet on Carcass and Meat Characteristics of Lambs at Ambient Temperatures of 20 and 30 o C

Artikel dalam bentuk PD

Gamma-Ray Emissions from Pulsars: Spectra of the TEV Fluxes from Outer-Gap Accelerators

We study the gamma-ray emissions from an outer-magnetospheric potential gap around a rotating neutron star. Migratory electrons and positrons are accelerated by the electric field in the gap to radiate copious gamma-rays via curvature process. Some of these gamma-rays materialize as pairs by colliding with the X-rays in the gap, leading to a pair production cascade. Imposing the closure condition that a single pair produces one pair in the gap on average, we explicitly solve the strength of the acceleration field and demonstrate how the peak energy and the luminosity of the curvature-radiated, GeV photons depend on the strength of the surface blackbody and the power-law emissions. Some predictions on the GeV emission from twelve rotation-powered pulsars are presented. We further demonstrate that the expected pulsed TeV fluxes are consistent with their observational upper limits. An implication of high-energy pulse phase width versus pulsar age, spin, and magnetic moment is discussed.Comment: Revised to compute absolute TeV spectra (22 pages, 9 figures

Opportunistic pathology-based screening for diabetes

OBJECTIVE To determine the potential of opportunistic glycated haemoglobin (HbA1c) testing of pathology samples to detect previously unknown diabetes. DESIGN Pathology samples from participants collected for other reasons and suitable for HbA1c testing were utilised for opportunistic diabetes screening. HbA1c was measured with a Biorad Variant II turbo analyser and HbA1c levels of ≥6.5% (48 mmol/mol) were considered diagnostic for diabetes. Confirmation of previously unknown diabetes status was obtained by a review of hospital medical records and phone calls to general practitioners. SETTING Hospital pathology laboratory receiving samples from hospital-based and community-based (CB) settings. PARTICIPANTS Participants were identified based on the blood sample collection location in the CB, emergency department (ED) and inpatient (IP) groups. Exclusions pretesting were made based on the electronic patient history of: age <18 years, previous diabetes diagnosis, query for diabetes status in the past 12 months, evidence of pregnancy and sample collected postsurgery or transfusion. Only one sample per individual participant was tested. RESULTS Of the 22 396 blood samples collected, 4505 (1142 CB, 1113 ED, 2250 IP) were tested of which 327 (7.3%) had HbA1c levels ≥6.5% (48 mmol/mol). Of these 120 (2.7%) were determined to have previously unknown diabetes (11 (1%) CB, 21 (1.9%) ED, 88 (3.9%) IP). The prevalence of previously unknown diabetes was substantially higher (5.4%) in hospital-based (ED and IP) participants aged over 54 years. CONCLUSIONS Opportunistic testing of referred pathology samples can be an effective method of screening for diabetes, especially in hospital-based and older persons.This project was supported by a grant from the Canberra Hospital Private Practice Trust Fund