TeV radiation from the Crab nebula and other matters

The detection of the Crab Nebula via the Cherenkov imaging technique places TeV astronomy on a secure observational footing. The motivation for TeV observations, a discussion of the atmospheric Cherenkov technique, the experimental details of the Crab Nebula detection, and its scientific implications are presented. The present dilemma of VHE/UHE astronomy is that the Crab appears to be the only source whose showers match theoretical expectations. The situation will be clarified as improved ground-based detectors come on-line with sensitivities matching those of the GRO (Gamma Ray Observatory) instruments

Search for an X-ray identification of a strong gamma-ray source

X-rays from Cygnus X-3 were observed during early 1978 with the detectors of the SAS-3 satellite. These observations in conjunction with earlier UHURU and ANS data indicate that the 4.8 hr period of Cygnus X-3 is increasing at the rate of P/P = (5/1 plus or minus 1.3) x 10 to the minus 6 power/1 yr. The sign and magnitude for this change are incompatible with a rotation model for the period and are in reasonable agreement with model predictions for orbital changes associated with mass loss and transfer in a binary system

X-ray emission from the region of gamma 195+5

X-ray observations of nineteen unidentified discrete celestial gamma ray sources are discussed. Results show some indication of X-rays from the gamma ray source region. On the assumption that the results are valid, it is concluded that the source error box is smaller than what it was

Microwave holography for nondestructive testing

Holographic methods permit use of very large effective apertures so that weak signals can be collected over wide area and integrated to form image. Technique, modification of side-looking radar principle, can be used at very short ranges needed for nondestructive inspection of test specimens

GeV Gamma-Ray Sources

We report on the preliminary extension of our work on cataloging the GeV sky to approximately 7 years of CGRO/EGRET observations with special emphasis on a search for transient sources. The search method and significance levels are presented. Our initial results on 13 possible transients indicate that 3 may be new gamma-ray sources. Sixteen new steady GeV sources are also detected, 3 of which have never been reported as gamma-ray sources

An evaluation of the training of telephonists

The research described in this thesis is part of a study undertaken by the Post Office to determine criteria for the evaluation of training. In particular the training of operators for switchboards at Auto Manual Centres (AMCs) is investigated. This is done both at AMCs and in training centres known as Wing Schools. The similarilies and differences between the training at AMCs and Wing Schools are discussed, together with a brief outline of the work itself and the recruitment process. The work is considered quasi-repetitive, and includes an element of decision-making. Measures of output exist, which are used by management to determine staffing levels. These measures are considered for the purpose of assessing training effectiveness, which is seen as the core of the problem of evaluating training. However, they are shown to be unsuitable in this role, and a simpler measure of progress is proposed. By activity sampling methods, the existence of activity profiles is shown for experienced operators. The profiles are affected by the traffic mix in the AMC, but are seen as a means of comparing trainees' progress in different locations. Activity sampling observations of trainees compare the effects of practice on live and simulated traffic during their initial training period, and for a further five months of post-training experience. Additionally, comparisons are drawn between successful and unsuccessful trainees. Next, objective tests using partial simulation of call situations are used to compare different methods of studying programmed texts. No difference is found between the methods but a comparison is made also between two different orders of training, wilh positive results. A brief study of costs shows that training in an AMC is Iikely to cost very much less than in a school, but also indicates that improved selection would show financial returns. The principal conclusions are that (a) Common activiy-profiles exist for trained operators within a particular exchange. (b) The profiles can be used in the assessment of training performance. (c) The benefit of training operators for Directory Enquiry work initially and subsequently training for switchboard operation should be given further investigation. (d) Training in an AMC is more cost-effective than at a Wing School. (e) A trainability test should be a useful addition to the present selection procedures