19,395 research outputs found
High-speed pulse camera
Miniaturized, 16 mm high speed pulse camera takes spectral photometric photographs upon instantaneous command. The design includes a low-friction, low-inertia film transport, a very thin beryllium shutter driven by a low-inertia stepper motor for minimum actuation time after a pulse command, and a binary encoder
The Meaning of Animals
This research examines the social construction of animals by a rural Allegheny culture using a linguistic approach based on estimating the set of attributes associated with the words they used to describe animals. We asked 268 respondents to free-associate with the nouns, chicken and deer when seen in a context of other words related to nature. Their responses were coded and the frequencies of of words and word groupings were tabulated for sub-samples of differing age, gender and occupation. Response words were categorized into seven typologies including two affective types. The results indicate that except for possibly the very young, the social meanings of chicken and deer did not vary with gender, age or occupation. The respondents interpretation of living chicken was indistinguishable from that of unprepared food. Their interpretation of deer was broader and primarily one of interaction with a lesser adversary
CAD and creativity: does the computer really help?
We are frequently told by its exponents that computeraided design (CAD) liberates designers and gives them new ways of envisioning their work, but is this really true? CAD in architecture is examined to see to what extent it has enhanced creativity in design. This is partly
done by applying a test of creativity advanced by contemporary architect Herman Hertzberger. In this analysis, CAD is found somewhat wanting,
and some suggestions are made as to why this might be so
A study of some aspects of growth and reproduction in two inbred lines of mice and their crosses : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science in Massey University of Manawatu
The mating of closely related individuals is generally believed to result in inferior offspring. Recognition of this danger has been suggested as the reason for evolution of human social customs. However, historical researches suggest that inbreeding unavoidably occurred in small, isolated, ancient communities, and marriage of close relatives was encouraged in the Egyptian, Greek and Hebrew civilisations (Zirkle, 1952).
Inbreeding is likely to have occurred in the isolated flocks of nomads, but it is probable that inbreeding depression, as such, was not recognised until the eighteenth century when the early livestock improvers are reputed to have found that the fertility of their animals deteriorated with continued inbreeding.
Hybrid vigour from cross breeding plants was described by Koelreuter (1766)
and confirmed by later botanists., .After much detailed work, Darwin (1876) concluded:
" •••cross fertilisation is generally beneficial and self
fertilisation injurious." and that
(a) Mechanisms exist widely for the avoidance of inbreeding.
(b) Inbreeding has effects likely to incur selective disadvantages.
No suitable hypothesis could account for the usually deleterious effects of inbreeding, or the reverse phenomenon of hybrid vigour until the rediscovery of Mendel's work in 1900. The effects of inbreeding can now be explained in terms of the dominance and recessiveness of genes. (Falconer, 1960).
The aim of experiments reported in this thesis was to study growth, reproduction and mortality in two inbred lines of mice, derived from common ancestors, to find if differences between them had arisen during inbreeding.
Reciprocal crosses and matings of the F1 progeny of these crosses were made to
find if hybridisation of the parent lines led to improvements of these charactÂeristics.
This study was suggested by Drs. D.S.. Flux, M.F. McDonald and R.E. Munford to whom the author is indebted for advice and guidance.
The author also wishes to acknowledge the assistance of Mr. E. Ormsby in histological preparations, of Mr. P .S. Dale in photomicrography, and of
Mr. C. Muir who drew some of the figures reproduced in this thesis. Thanks are also due to the staff of the University Library for their efforts in obtaining literature. [From Preface
Isotropic Radio Background from Quark Nugget Dark Matter
Recent measurements by the ARCADE2 experiment unambiguously show an excess in
the isotropic radio background at frequencies below the GHz scale. We argue
that this excess may be a natural consequence of the interaction of visible and
dark matter in the early universe if the dark matter consists of heavy nuggets
of quark matter. Explanation of the observed radio band excess requires the
introduction of no new parameters, rather we exploit the same dark matter model
and identical normalization parameters to those previously used to explain
other excesses of diffuse emission from the centre of our galaxy. These
previously observed excesses include the WMAP Haze of GHz radiation, keV X -ray
emission and MeV gamma-ray radiation.Comment: updated plot and references reflecting a revised analysis of the
isotropic radio background exces
Improved gas ring laser
Minimizing mode coupling improves sensing resolution of a gas ring laser in a gimballess gyroscope system or inertial rotation sensor. The piezoelectric-driven corner mirrors of the ring laser are oscillated in a direction parallel to their surfaces and the plane of rotation
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