9 research outputs found
Establishment guide for sub-tropical grasses : key steps to success
Sub-tropical perennial grasses are now widely sown in the Northern Agricultural region (NAR) and on the south coast of Western Australia (WA). Since 2000, more than 50 000 ha have been sown to perennial grasses in the NAR and about 150 000 ha on the south coast, mainly kikuyu.https://researchlibrary.agric.wa.gov.au/bulletins/1034/thumbnail.jp
The Minimum Volume Covering Ellipsoid Estimation in Kernel-Defined Feature Spaces
Abstract. Minimum volume covering ellipsoid estimation is important in areas such as systems identification, control, video tracking, sensor management, and novelty detection. It is well known that finding the minimum volume covering ellipsoid (MVCE) reduces to a convex optimisation problem. We propose a regularised version of the MVCE problem, and derive its dual formulation. This makes it possible to apply the MVCE problem in kernel-defined feature spaces. The solution is generally sparse, in the sense that the solution depends on a limited set of points. We argue that the MVCE is a valuable alternative to the minimum volume enclosing hypersphere for novelty detection. It is clearly a less conservative method. Besides this, we can show using statistical learning theory that the probability of a typical point being misidentified as a novelty is generally small. We illustrate our results on real data.
Virtual Seminar on the Bioapparatus
Includes a text based on transcripts of proceedings of a seminar on the "bioapparatus," conceived as the focus of issues concerning technology and the body. Statements by 20 artists and writers treat such topics as natural artifice, designing the social, virtual reality, art machines, and aural/visual space. Biographical notes on the participants
Bright radio emission from an ultraluminous stellar-mass microquasar in M 31
A subset of ultraluminous X-ray sources (those with luminosities of less than 1040 erg s−1; ref. 1) are thought to be powered by the accretion of gas onto black holes with masses of ~5–20 , probably by means of an accretion disk2, 3. The X-ray and radio emission are coupled in such Galactic sources; the radio emission originates in a relativistic jet thought to be launched from the innermost regions near the black hole4, 5, with the most powerful emission occurring when the rate of infalling matter approaches a theoretical maximum (the Eddington limit). Only four such maximal sources are known in the Milky Way6, and the absorption of soft X-rays in the interstellar medium hinders the determination of the causal sequence of events that leads to the ejection of the jet. Here we report radio and X-ray observations of a bright new X-ray source in the nearby galaxy M 31, whose peak luminosity exceeded 1039 erg s−1. The radio luminosity is extremely high and shows variability on a timescale of tens of minutes, arguing that the source is highly compact and powered by accretion close to the Eddington limit onto a black hole of stellar mass. Continued radio and X-ray monitoring of such sources should reveal the causal relationship between the accretion flow and the powerful jet emission