La verdadera amenaza para nuesto futuro es que se acaba el agua

El «pico del petróleo» ha generado titulares en los últimos años, pero la verdadera amenaza para nuestro futuro es el «pico del agua». Hay sustitutos para el petróleo, pero no para el agua. Podemos producir alimentos sin petróleo, pero no sin agua

A Preliminary Investigation of Chromite

The purpose of this thesis was to study the effects of cryolite and a mixture of cryolite and aluminum oxide on a chromite concentrate with special reference to the ability to break the bond between the ferrous iron and chromic oxide in the chromite

Preweaning body measurements of beef calves and traits of their dams as predictors of calves\u27 postweaning and lifetime performance

Body measurements, body composition traits and certain performance traits of 74 Angus bull and 84 Angus heifer calves, recorded at three different observations up to weaning, were studied to assess their value as predictors of postweaning ADG, lifetime ADG (ADG from birth until the end of test), final condition scope and fat thickness (measured ultrasonically when the postweaning feeding period was terminated). n These calves were born from January 17, 1968, to April 26, 1968. A stepwise regression procedure was employed to construct prediction equations. Traits that could enter the regression equation as independent variables included heart girth, back length, loin length, rump length, total length, type score, condition score, weight and age. Also, fat thickness measured ultrasonically over the twelfth and thirteenth ribs at weaning was considered among the independent variables. Coefficients of multiple determination (R2) for the equations to predict the dependent variables tended to be larger when the independent variables were the calves\u27 weaning traits rather than preweaning or interim traits. It was concluded that if the dependent variables are to be predicted from calf traits observed at only one time of observation, that observation should be taken at an average age of about 220 to 225 days (weaning). Various combinations of the weaning body measurements and body composition traits explained significantly (P \u3c .05) more variation in postweaning ADG, lifetime ADG, final condition score and final fat thickness than was explained by weight and age alone. For bulls, the increases in R2 were 0.239, 0.113, 0.155, and 0.207, respectively, for the dependent variables enumerated above. In the case of heifers, the increases in R2 were 0.277, 0.089, 0.105, and 0.1A6, respectively. Hence, it appears from these results that body dimension measurements and estimates of fatness can be used effectively to improve the predict tion of calf performance and subsequent body composition over conventional methods utilizing only calf weight and age. The addition of traits of the dam (weight and condition score and linear, squared and cubed forms of change in weight and condition of the dam from April, 1968, until time of observation of calf) to the regression equations, after entering the calf traits, generally did not result in significant increases in the R2 values for predicting postweaning and lifetime ADG. These cow variables tended to be slightly more important as predictors of final condition score and fat thickness of the calves. It is doubtful that the additional precision in predicting future performance and body composition of calves obtained by considering these traits of the dams, is large enough to warrant the extra effort and expense necessary to obtain these data

Theoretical basis for state vector comparison, relative position display, and relative position/rendezvous prediction

This thesis outlines the theoretical underpinnings used for the software designed to meet Detailed Technical Objectives 700-6 and 700-7 for the Space Shuttle Discovery mission STS-5 1. The primary goal was to compare state vector information produced by an on board GPS receiver and Discovery's computers, and provide real time display of the results. Because state vector information for the ORFEUS/SPAS payload was also available, relative position and rendezvous information between Discovery and ORFEUS/SPAS was made possible. Analysis of the various state vectors was used to produce a graphical display, in an operationally meaningful format, to the flight crew of Discoveryhttp://archive.org/details/theoreticalbasis00makeApproved for public release; distribution is unlimited

Star formation in the inner galaxy: A far-infrared and radio study of two H2 regions

Far-infrared and radio continuum maps have been made of the central 6' of the inner-galaxy HII regions G30.8-0.0 (in the W43 complex) and G25.4-0.2, along with radio and molecular line measurements at selected positions. The purpose of this study is an effort to understand star formation in the molecular ring at 5 kpc in galactic radius. Measurements at several far infrared wavelengths allow the dust temperature structures and total far infrared fluxes to be determined. Comparison of the radio and infrared maps shows a close relationship between the ionized gas and the infrared-emitting material. There is evidence that parts of G30.8 are substantially affected by extinction, even at far-infrared wavelengths. Using radio recombination line and CO line data for G25.4-0.2, the distance ambiguity for this source is resolved. The large distance previously ascribed to the entire complex is found to apply to only one of the two main components. The confusion in distance determination is found to result from an extraordinary near-superposition of two bright HII regions. Using the revised distances of 4.3 kpc for G25.4SE and 12 kpc for G25.4NW, it is found that the latter, which is apparently the fainter of the two sources, is actually the more luminous. The ratio of total luminosity to ionizing luminosity is very similar to that of HII regions in the solar circle. Assuming a coeval population of ionizing stars, a normal initial mass function is indicated