Torsion of a malignant undescended testis

Cryptorchid testis have a greater risk of malignant change than do normally descended testis. The undescended testis would also be susceptible to torsion by the mechanism of increase in testicular size. A 36-year-old man of torsion of malignant undescended testis is presented. He was diagnosed as having incarcerated inguinal hernia on his first visit to general surgeon due to acute left lower abdominal pain. At laparotomy, a 7.5 x 5.5 x 3.0 cm3, greyish tan color mass was found. The pathological diagnosis is choricarcinoma and teratoma, mixed germ cell tumor. We would emphasise that in any patient presenting with acute abdominal symptoms and an absent scrotal testis, the possibility of a complication of torsion of undescended testis should be considered.     

Software development of interactive microcomputer programs used in teaching mathematics: A case history

This paper presents the experience of using microcomputers in the teaching of mathematics to undergraduates at Paisley College of Technology. The production of software for use by students has been a sizeable undertaking and the paper presents an account of the software development programme whose first stage was a formative and experimental period on which was based the specification of the software developed in the second stage. The definition and development of software tools for interactive programs to be used in mathematics teaching has been found to be of prime importance in producing the required software in a relatively efficient manner.     

Preparation and characterisation of Rb2CrCl4-xXx (X=Br,OR I,x=1,2, or 3)

Several new compounds based on the ionic ferromagnet Rb₂CrCl₄ but with Br or I substituting for Cl have been prepared in powder and single crystal form. The compounds have been characterised by chemical and X-ray analysis. The ordering of the anions within the K₂NiF₄ type structure is discussed.     

Apical cross-sectional echocardiography. Standard for the diagnosis of idiopathic mitral valve prolapse syndrome

In light of the nonspecificity of left ventricular angiography and physical examination, and the limitations of M-mode echocardiography to define the presence of mitral valve prolapse syndrome, we evaluated left ventricular longitudinal and apical four-chamber tomographic views of cross sectional echocardiography in 19 subjects with normal left ventricular cineangiography and in 5 patients with congestive cardiomyopathy. None had auscultatory findings suggestive of mitral valve prolapse syndrome. In all 24 control subjects, the apical view demonstrated the coaptation point and the leaflets of the mitral valve to lie inside the left ventricular cavity. A retrospective analysis of 900 consecutive cross sectional echocardiographic studies revealed 105 subjects with no evidence of structural heart disease other than the presence of the mitral valve leaflets in the left atrium in systole defining the existence of idiopathic mitral valve prolapse syndrome. Both mitral leaflets were prolapsed in 90 percent of the involved populations, and the apical tomographic cross sectional echocardiographic view was superior to the left ventricular longitudinal view for the detection of anterior leaflet prolapse. These data suggest that the apical cross sectional view may be the single best technique to define the presence of idiopathic mitral valve prolapse syndrome.     

Optimum Windows for Carrier Frequency Estimation

The energy spectrum [X2(f)] of a ?windowed sample? of an unmodulated RF carrier will generally exhibit a peak value at or near the carrier frequency. The location of this peak is frequently used in signal analysis as an estimate of the true carrier frequency. This paper investigates the error in such estimates in cases where the signal arrives in the presence of ?broad-band? additive noise and shows that the error is due to both the added noise and spectral ?leakage? effects. Both these error mechanisms are affected by window duration and window shape. This paper proceeds further to pose two optimization criteria for the selection of a ?best window? shape for the minimization of estimation error. The two criteria are related to two differing views of prior un-certainty about the actual carrier frequency. These criteria accordingly provide different, but similar forms for the optimum window. Moreover, in worsening signal-to-noise conditions, both forms of optimum window tend to a rectangular shape.     

Project Pathogens: The Anatomy of Omission Errors in Construction and Resource Engineering Project

Construction and engineering projects are typically complex in nature and are prone to cost and schedule overruns. A significant factor that often contributes to these overruns is rework. Omissions errors, in particular, have been found to account for as much as 38% of the total rework costs experienced. To date, there has been limited research that has sought to determine the underlying factors that contribute to omission errors in construction and engineering projects. Using data derived from 59 in-depth interviews undertaken with various project participants, a generic systemic causal model of the key factors that contributed to omission errors is presented. The developed causal model can improve understanding of the archetypal nature and underlying dynamics of omission errors. Error management strategies that can be considered for implementation in projects are also discussed.