Why neutron guides may end up breaking down? Some results on the macroscopic behaviour of alkali-borosilicate glass support plates under neutron irradiation

In this paper we report on a first part of a study on the mechanisms leading to brittle fracture in neutron guides made of glass as structural element. Such devices are widely used to deliver thermal and cold neu tron beams to experimental lines in most large neutron research facilities. We present results on macroscopic properties of samples of guide glass substrates which are subjected to neutron irradiation at relatively large fluences. The results show a striking dependence of some of the macroscopic properties such as density, shape or surface curvature upon the specific chemical composition of a given glass. The relevance of the present findings for the installation of either replacement guides at the existing facilities or for the deployment of instruments for ongoing projects such as the European Spallation Source is briefly discussed.

A preference for own-subspecies' song guides vocal learning in a song bird

In many song birds, males develop their songs as adults by imitating the songs of one or more tutors, memorized previously during a sensitive phase early in life. Previous work using two assays, the production of imitations by adult males and playback-induced calling by young birds during the sensitive phase for memorization, has shown that song birds can discriminate between their own and other species' songs. Herein I use both assays to show that male mountain white-crowned sparrows, Zonotrichia leucophrys oriantha, must learn to sing but have a genetic predisposition to memorize and learn the songs of their own subspecies. Playback tests to young naive birds before they even begin to sing reveal that birds give begging calls more in response to oriantha song than to songs of another species. After 10 days of tutoring with songs of either their own or another subspecies, birds continue to give stronger call responses to songs of their own subspecies, irrespective of whether they were tutored with them, and are more discriminating in distinguishing between different dialects of their own subspecies. The memory processes that facilitate recognition and discrimination of own-subspecies' song may also mediate the preferential imitation of song of a bird's own subspecies. Such perceptual biases could constrain the direction and rate of cultural evolution of learned songs.

Real-time detection of DNA hybridization and melting on oligonucleotide arrays by using optical wave guides.

The challenge of the Human Genome Project is to increase the rate of DNA sequence acquisition by two orders of magnitude to complete sequencing of the human genome by the year 2000. The present work describes a rapid detection method using a two-dimensional optical wave guide that allows measurement of real-time binding or melting of a light-scattering label on a DNA array. A particulate label on the target DNA acts as a light-scattering source when illuminated by the evanescent wave of the wave guide and only the label bound to the surface generates a signal. Imaging/visual examination of the scattered light permits interrogation of the entire array simultaneously. Hybridization specificity is equivalent to that obtained with a conventional system using autoradiography. Wave guide melting curves are consistent with those obtained in the liquid phase and single-base discrimination is facile. Dilution experiments showed an apparent lower limit of detection at 0.4 nM oligonucleotide. This performance is comparable to the best currently known fluorescence-based systems. In addition, wave guide detection allows manipulation of hybridization stringency during detection and thereby reduces DNA chip complexity. It is anticipated that this methodology will provide a powerful tool for diagnostic applications that require rapid cost-effective detection of variations from known sequences.

Plan de Marketing de Little Girl

La empresa a la que se dirige este Plan de Marketing es Little Girl, en la cual su actividad principal es la venta detallista de ropa y accesorios. La diferencia con el resto de tiendas, tanto tradicionales como con menos renombre, es que se ha especializado en un target concreto, y con lo cual, en un producto concreto, siendo dirigirse hacia mujeres que ronden el 1,60 cm de altura. Este Plan de Marketing se basa en acciones de comunicación eficaces y concretas, acorde con los recursos de una pequeña empresa que abre negocio y es nueva, y fijados para un horizonte temporal de 4 años, en previsión de que va a tener éxito, en el mejor de los casos, o que puede subsistir al menos.

Sex in industry: a plea for the working-girl

by Azel Ames.

Letters of a business woman to her daughter, and, Letters of a business girl to her mother

by Zora Putnam Wilkins.

The jungle girl /

Mode of access: Internet.

Girl holding treat for rabbit / McKenzie Hosp. Schools

side 2

Santa giving present to a girl sitting on woman's lap

side 2

Little girl with one hand in air, the other holding cupcake, sitting on woman's lap

side 2

Guides to pollution prevention : the pesticide formulating industry.

Mode of access: Internet.

Manual of protective action guides and protective actions for nuclear incidents.

"EPA 520/1-75-001-A"--Cover.

Guides to pollution prevention : the mechanical equipment repair industry.

Mode of access: Internet.