Finding the Origin of the Pioneer Anomaly

Analysis of radio-metric tracking data from the Pioneer 10/11 spacecraft at distances between 20 - 70 astronomical units (AU) from the Sun has consistently indicated the presence of an anomalous, small, constant Doppler frequency drift. The drift can be interpreted as being due to a constant acceleration of a_P= (8.74 \pm 1.33) x 10^{-8} cm/s^2 directed towards the Sun. Although it is suspected that there is a systematic origin to the effect, none has been found. As a result, the nature of this anomaly has become of growing interest. Here we present a concept for a deep-space experiment that will reveal the origin of the discovered anomaly and also will characterize its properties to an accuracy of at least two orders of magnitude below the anomaly's size. The proposed mission will not only provide a significant accuracy improvement in the search for small anomalous accelerations, it will also determine if the anomaly is due to some internal systematic or has an external origin. A number of critical requirements and design considerations for the mission are outlined and addressed. If only already existing technologies were used, the mission could be flown as early as 2010.Comment: 21 SS pages, 4+1 figures. final changes for publicatio

Entanglement of separate nitrogen-vacancy centers coupled to a whispering-gallery mode cavity

We present a quantum electrodynamical model involving nitrogen-vacancy centers coupled to a whispering-gallery mode cavity. Two schemes are considered to create W state and Bell state, respectively. One of the schemes makes use of the Raman transition with the cavity field virtually excited; The other enables the Bell state preparation and quantum information transfer by virtue of dark state evolution and adiabatic passage, which is tolerant to ambient noise and experimental parameter fluctuations. We justify our schemes by considering the experimental feasibility and challenge using currently available technology.Comment: 8 pages and 5 figure

Ontwikkelingsvooruitsigte in die Oos-Transvaalse Laeveld

Hierdie landstreek is ongetwyfeld die deel van ons land waar in die naaste toekoms die grootste ontwikkeling gaan plaasvind, nie alleen op landbougebied nie, maar ook op minerale-en nywerheidsgebied

Agtergrond, persoonlikheid en ekonomiese denke

Dit is die bedoeling om hier, in ’n baie kort bestek en slegs in hooftrekke, aan te toon dat die ekonomiese denke onafskeidbaar verbonde is aan die persoonlikheid en agtergrond van die ekonoom

Los gedagtes oor die plek van landbou in ons volkshuishouding.

Die bepaling van die plek van landbou in enige volkshuishouding kan van meer as een aspek benader word

„In die jaar 2000.”

Die mens is gewoonlik bevrees vir wat die more te voorskyn mag bring.Die geskiedenis laat hom nie toe om van sy erfenis weg te vlug nie. Terselfdertyd is dit die geskiedenis wat die mens in staat stel om met ’n enigsinsvoorbedagte beplanning op te tree. Alle lewe is ’n proses en alle prosesseis van nature iets dinamies. Dit is tevergeefs om daarna te strewe, metenige hoop van sukses, om ’n oomblik van die verlede te herwin. Suksesis nooit finaal nie. As die mens ’n beter muisval bou, sal die natuur mettertyd’n skelmer muis baar