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Following Colquhouu's more general result that in a vigilance task probability rather than frequency of occurrence determines an operator's efficiency, the effect of ‘ probability ’ has been tested on the shop floor for probabilities in the range 0·01 to 0·05 for paced and unpaced inspection. A ‘ probability ’ effect was found for the ‘ unpaced condition ’. Raising the probability increased the level of detection of defects significantly The practical and theoretical implications of the current study are discussed: particularly relating the relevance of laboratory studies to practical situations.

On the basis of simple theoretical considerations it is expected that short-lived positron emitters should be produced in fluorine, sodium, and magnesium under bombardment with 6-Mev protons. These activities have been found and ascribed to ${\mathrm{Ne}}^{19}$, ${\mathrm{Mg}}^{23}$, and ${\mathrm{Al}}^{25,\phantom{\rule{0ex}{0ex}}26}$. Half-lives, positron spectra and threshold investigations have been made and found to compare very well with the theory. It is concluded that for isobars of the type $(n\ensuremath{-}p)=\ifmmode\pm\else\textpm\fi{}1$ the difference in binding energy is due solely to the effect of Coulomb forces up to at least mass number 25. The half-lives are found to depend on the inverse fifth power of the upper limit of the positron spectra in agreement with the theory.

A case of lymphocytic leukaemia with metastatic brain lesions and a concurrent Cladosporium trichoides infection is described in a cat. The lesions in the brain consisted of haemorrhage, foci of neoplastic cells in the parenchyma and perivascular cuffing with neoplastic cells. Lesions due to Cladosporium were found only in the kidney and were circumscribed necrotic areas surrounded by neutrophils and macrophages with hyphae in the centre. Identification of the fungus was made by growth characteristics, morphology, biochemical tests and experimental animal inoculation. Resume. On decrit, chez un chat, un cas de leucetmie lymphocytique avec des lesions cerebrales metastatiques et une infection concourante Cladosporium trichoides. Les lesions cerebrales consistaient en une hemorragie, des foyers de cullules neoplastiques dans le parenchyme et un cuffing perivasculaire avec cellules neoplastiques. On a trouve des lesions dues au Cladosporium dans le rein seulement et elles etaient des regions necrotiques circonscrites entourees de neutrophils et de macrophages avec des hyphes au centre. On a identifie le fongus grâce aux caracteristiques de croissance, a la morphologie, a des tests biochimiques et a une infection chez des animaux experimentaux. Zusammenfassung. Lymphozythamische Leukamiemit metastatischer Gehirnverletzung und begleitender Cladosporium trichoides Infiszierung, ist im Fall einer Katze beschrieben. Die Gehirnverletzung bestand aus Blutung, Foci der neoplastischen Parenchyma Zellen und perivaskularer Cuffing der neoplastichen Zellen. Cladosporium entstammende Verletzungsspuren wurden nur in der Niere entdeckt, und zwar, als abgestorbene Zonen, die von Hyphen-kernigen Neutrophil und Makrophage umrahmt waren. Die Fungus Identifikation wurde an Merkmale des Wachstums, Morphologie, biochemischen Proben und Infektion der Versuchstiere, vorgenommen.

The Ritz theory of electromagnetism and optics is criticized in relation to the experimental evidence after the introduction of a simple and natural modification of the hypothesis concerning the velocity of radiation scattered by the electrons of a medium. It is argued that the theory is then in harmony with the electron theory of dispersion, accounts satisfactorily for aberration, the first-order Doppler effect from moving sources and interferometer experiments on binary stars. There is no evidence from binary stars which contradicts it. It is compatible with the second-order Doppler effect and possibly the Fizeau experiment since arguments are advanced which indicate that these phenomena depend essentially on the momentum and energy of radiation. Other phenomena are discussed. It is concluded that the best evidence against the theory comes from experiments on the lifetimes of fast mesons and the velocity of γ rays and light from moving sources. The justifications for the discussion are the desirability ...

Measurements were made of the rate at which typists keyed two-letter sequences when typing continuous material at the overall rate of 80 words per minute. The results were used to estimate the maximum output rate which should be allowed for in the design of a machine having a typewriter keyboard as an input source if the operator is to have an unpaced task.

The 0-3, 0-4, 0-5 and 0-6 bands of a new band system of the ${\mathrm{C}}_{2}$ molecule are analyzed. The lower state, $^{3}\ensuremath{\Pi}$, is the same as the lower state of the Swan bands (in all probability the ground state). The upper state is a new $^{3}\ensuremath{\Pi}_{g}$ state. The rotational and vibrational constants of the upper and lower state are given in Table VII. While the constants for the upper state are entirely new those for the lower state (ground state) are considerably improved over those at present in the literature. The triplet splitting and staggering in the new bands is much larger than in the Swan system. In the $^{3}\ensuremath{\Pi}_{0}\ensuremath{-}^{3}\ensuremath{\Pi}_{0}$ component a reversal of the staggering is observed. The electron configuration of the new state is briefly discussed. Finally a number of other bands, very probably due to ${\mathrm{C}}_{2}$, but not yet analyzed, are given.

It is pointed out that the extinction theorem of dispersion theory, for which an elementary derivation is given, shows that an incident light wave is extinguished at the surface of a dielectric. This may mean that information about the velocity of light from a moving source would be lost if the light passed through intervening transparent, stationary material before it was measured. All past laboratory measurements to verify the constancy of the velocity of light from moving light sources and mirrors and from extraterrestrial sources were made only after the light had passed through stationary material. Double stars, especially close binary pairs, are surrounded by a common envelope of gas which may contain enough matter to extinguish the direct light from the stars. Thus de Sitter's proof of the constancy of the velocity of light may not be conclusive. It is concluded that there may not exist any sure experimental evidence for the second postulate of special relativity.

Serious difficulties from extinction are shown to exist in the interpretation of past experiments on $\ensuremath{\gamma}$ rays from moving sources. We have measured the relative speed of the two $\ensuremath{\gamma}$ rays emitted forward and backward by a ${\ensuremath{\pi}}^{0}$ meson decaying in flight. The velocity of the neutral pions, which were produced in the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}+n$, was $v=0.2c$. We have compared our results with what would have been expected, taking account of extinction, on the assumption that the initial photon velocities were $c+v$ and $c\ensuremath{-}v$. The results were in complete disagreement with this assumption.

A 5-year-old male Golden Retriever was examined because of a chronic localizedloss of hair and elevated, multiple white nodules 2-8 mm in diameter that coalesced in several areas on the right side of the neck. The principle change was marked hyperplasia of the dermal collagen. The lesion is compatible with the connective tissue nevus described in man. Connective tissue nevus in man was first described in 1921 by LEWAN- DOWSKY (3). In the three cases the skin lesion was on one side of the chest and consisted of slightly raised yellowish, multiple 1-5 mm papules. There was disappearance and degeneration of elastic fibers along the epidermal- dermal junction and in dermal papillae. Since that time similar lesions have been reported - some with hyperplasia or degeneration in the elastic tissue, others with a coarsening and homogenization of the collagen bundles, or a combination of the two. This paper gives what is believed to be the first report of a connective tissue nevus in an adult dog.

Two forms of type face, Gothic Elite and Standard Elite, wore compared for readability (i) when the emphasis was on comprehension and (ii) when it was on speed. No significant difference was found between the reading times for the two typo faces when reading for comprehension but Standard proved superior to Gothic when speed was the more important. Possible reasons for these differing results under the two conditions are considered.

In order to measure the effects of gross changes in the design of the pole and yoke for a large synchrocyclotron cheaply and conveniently, a model half‐magnet having a two‐inch diameter pole was constructed. From data on the fields produced by poles of various lengths using a fixed amount of copper in the coil, the pole length for which the cost of power and magnet steel was a minimum could be determined. Measurements of the efficiencies of poles of various shapes indicated that it would be possible to design a shimmed pole to have an efficiency of 70 to 75 percent at a field of 20,000 gauss. Finally data on over‐all magnet efficiency as a function of the ratio of the cross‐sectional areas of the yoke and pole permitted calculation of the ratio for which the cost of steel, copper, and power would be a minimum.

We have calculated the effective mass of the spring in an oscillating mass-spring system. It varies from 4/π2 to 13 the mass of the spring as the suspended mass varies from 0 to ∞. This and the various predicted modes can be easily verified experimentally.

The total cross section for the reaction p + p yields pi /sup +/ + p + n has been measured for 437-Mev incident protons. The value obtained is 1.06 plus or minus 0.24 mb, which is lower than some earlier measurements have indicated. The present result gives better agreement with the value predicted by the phenomenological theory and the measured cross section for p + p yields pi / sup =/ + d. (auth)

Two adult, female rhesus monkeys (Macaca mulatta) became depressed, weak, anorectic, and adipsic. Auscultation of the thorax of 1 monkey revealed bilateral harsh rales. Neither monkey responded to therapeutic doses of antibiotics, and both died soon after treatment was started. Meningitis was demonstrated histologically and pure cultures of multiply antibiotic-resistant Klebsiella were isolated from the brains of both monkeys. Of 13 clinically normal rhesus monkeys in the same facility, 5 had multiply antibiotic-resistant Klebsiella spp in their pharynges.

Skin biopsies were taken from 16 monkeys with measles rash. Histopathological changes consisted of multinucleated epithelial giant cells in the epidermis and hair follicles, proliferative and degenerative changes of the epidermis, and mild inflammation of the dermis. Necropsies were performed on two monkeys with a typical rash and on 26 additional monkeys that died during outbreaks in the colony. Lesions attributable to rubeola virus were found in the respiratory system, lymphoid system, gastrointestinal tract, salivary glands, thyroid gland, liver, pancreas, and urinary system. In these organs the finding that was characteristic of measles was the presence of syncytial giant cells, some of which contained both intranuclear and cytoplasmic inclusions. The significance of syncytia and the mechanism of their formation are discussed.

The newborn screening program for hereditary metabolic disorders in Manitoba is reviewed. In 1965, screening was begun on infants born in Metropolitan Winnipeg, and since January 1966 screening has been provincewide. Bloods from 85,868 infants have been screened so far. For the past two-and-a-half years 98.5% of live-born infants surviving the first seven days of life have been screened.The Guthrie bacterial inhibition test was used initially. In 1966 an evaluation was undertaken of one-dimensional amino-acid paper chromatography, and in 1969 this method replaced the Guthrie test. Five cases of phenylketonuria have been identified, and incidence of 1:17, 174. Screening for abnormal sugars in the blood has disclosed two cases of galactosemia. The incidence of galactosemia in the province is 1 in 16,069 live births.

Naturally-occurring streptocarosis, caused by Streptocara incognita Gibson, 1968, was diagnosed in two Chilean flamingos, Phoenicopterus chilensis. Ulcerative lesions of the proventriculus and gizzard caused by the nematodes resulted in a severe debilitative condition and eventual death. Streptocara incognita has been reported previously only in anseriform birds.