IPNS grooved, solid methane moderator

There are two motives for using cold moderators in pulsed neutron sources, to provide higher fluxes of long-wavelength neutrons, and to extend the epithermal range with its short pulse structure to lower energies. For both these purposes solid methane, operated at the lowest possible temperatures, is the best material we know of. Two problems accompany the use of solid methane in high power sources, namely heat transport in view of the low thermal conductivity of solid methane, and deterioration due to radiation damage. We have designed a system suitable to operate in IPNS, subject to nuclear heating of about 25 W, which incorporates an aluminum foam matrix to conduct the heat from within the moderator. We report the results of the first few months' operation and of a few tests that we have performed

Calculation of protein domain structural similarity using two-dimensional representations

By reducing protein structures to two-dimensional representations, it is possible to speed up the alignment of the structures and hence calculate similarity indices faster that using three-dimensional representations. Using amino acid based representations gives much better discrimination between proteins and faster calculations. Taking into account the relative similarity of the amino acids involved allowed improved accuracy at very little time cost

As exposições universais e o cinema: história e cultura

O artigo tem por objetivo examinar a presença do cinema nas exposições universais entre 1893 (World's Columbian Exposition, Chicago) e 1939 (New York World's Fair). Integrante de uma cultura visual construída por esses espaços dedicados a celebrar o capitalismo, o cinema tem sua trajetória identificada à das diferentes feiras mundiais pela sua capacidade de entreter e, ao mesmo tempo, educar. Consolidando-se como meio de comunicações de massas em meio à Primeira Guerra Mundial, participará de maneira mais intensa das disputas simbólicas de um mundo prestes a entrar em seu segundo conflito mundial. Atingirá um público mais amplo, constituindo-se na principal 'vitrine' em que a nação projeta as virtudes a serem comemoradas. O novo grande espetáculo visual assumirá, nesse quadro, maior destaque por meio de filmes idealizados como verdadeiros monumentos cinematográficos