Water detection at the moon, Mars and comets with a combined neutron gamma ray instrument

Measuring the fluxes of thermal and epithermal neutrons at a planetary object in conjunction with gamma-ray spectroscopic observations will provide information about the chemical composition of the surface which is less model dependent than the gamma ray measurements by themselves. Researchers devised a passive neutron detector for this purpose. An experimental model was designed and built. Three variables provided the basis for a set of experiments: thickness of the Sm and B layers, the presence or absence of the ACS, and the position of the source relative to the PND's cylindrical axis. Experimental results are given

Study of an attitude control system for the astronaut maneuvering unit final report, dec. 1963 - jul. 1964

Attitude control system for astronaut maneuvering unit

Quality, quantity and precision of depth perception in stereoscopic displays

Stereoscopic 3D viewing (S3D) can create a clear and compelling improvement in the quality of the 3D experience compared with 2D displays. This improvement is distinct from any change in the amount of depth perceived, or the apparent 3D shapes of objects and the distances between them. It has been suggested instead that the enhanced feeling of realness is associated more with the precision with which we see depth. We measured the contribution of stereoscopic cues to the quality of depth perception in simple abstract images and complex natural scenes. We varied the amount of disparity present in the simple scenes in order to dissociate the magnitude and precision of perceived depth. We show that the qualitative enhancement of perceived depth in stereoscopic displays can be readily quantified, and that it is more closely related to the precision than to the magnitude of apparent depth. It is thus possible to make a distinction between scenes that contain more depth, and those that contain better depth

External and internal noise surveys of London primary schools

Internal and external noise surveys have been carried out around schools in London, UK, to provide information on typical levels and sources to which children are exposed while at school. Noise levels were measured outside 142 schools, in areas away from flightpaths into major airports. 86% of the schools surveyed were exposed to noise from road traffic, the average external noise level outside a school being 57 dB LAeq. Detailed internal noise surveys have been carried out in 140 classrooms in 16 schools, together with classroom observations. It was found that noise levels inside classrooms depend upon the activities in which the children are engaged, with a difference of 20 dB LAeq between the 'quietest' and 'noisiest' activities. The average background noise level in classrooms exceeds the level recommended in current standards. The number of children in the classroom was found to affect noise levels. External noise influenced internal noise levels only when children were engaged in the quietest classroom activities. The effects of the age of the school buildings and types of window upon internal noise were examined but results were inconclusive

A Method for Determining Asymptotes of Home-Range Area Curves

Home-range area curves are used to estimate the number of locations needed to accurately estimate home range size based on the asymptote of the curve. However, the current methodology used to identify asymptotes for home-range area curves is largely subjective and varies between studies. Our objective was to evaluate the use of exponential, Gompertz, logistic, and reciprocal function models as a means for identifying asymptotes of home-range area curves. We radio monitored northern bobwhite (Colinus virginianus) coveys during mid-September through November 2001-2002 in Jim Hogg County, Texas. We calculated home-range size of radiomarked coveys using the 95% fixed kernel with least squares cross validation and minimum convex polygon estimators. We fitted area observations and coefficient of variation to the number of locations using exponential, Gompertz, logistic, and reciprocal function models to estimate the minimum number of locations necessary to obtain a representative home range size for each home range estimator. The various function models consistently provided a relatively good fit for home range area curves and coefficient of variation curves (0.58 ≤ R2 0.99; P \u3c 0.05) for both home range estimators. We used an information-theoretic framework (AICC) to select the best model to estimate area-curve asymptotes. The use of function models appears to provide a structured and useful approach for calculating area-curve asymptotes. We propose that researchers consider the use of such models when determining asymptotes for home-range area curves and that more research be conducted to validate the strength of this method

Gravitational intraction on quantum level and consequences thereof

The notion of gravitational emission as an emission of the same level with electromagnetic emission is based on the proven fact of existence of electrons stationary states in its own gravitational field, characterized by gravitational constantComment: 22 pages, 9 figure

LoCuSS : exploring the connection between local environment, star formation, and dust mass in Abell 1758

We explore the connection between dust and star formation, in the context of environmental effects on galaxy evolution. In particular, we exploit the susceptibility of dust to external processes to assess the influence of dense environment on star-forming galaxies. We have selected cluster Abell 1758 from the Local Cluster Substructure Survey (LoCuSS). Its complex dynamical state is an ideal test-bench to track dust removal and destruction in galaxies due to merger and accretion shocks. We present a systematic panchromatic study (from 0.15 mu m with GALEX to 500 mu m with Herschel) of spectroscopically confirmed star-forming cluster galaxies at intermediate redshift. We observe that the main subclusters (A1758N and A1758S) belong to two separate large-scale structures, with no overlapping galaxy members. Star forming cluster members are found preferentially outside cluster central regions, and are not isotropically distributed. Rather, these galaxies appear being funneled towards the main subclusters along separate accretion paths. Additionally, we present the first study of dust-to-stellar (DTS) mass ratio used as an indicator for local environmental influence on galaxy evolution. Star-forming cluster members show lower mean values (32 per cent at 2.4 sigma) of DTS mass ratio and lower levels of infrared emission from birth clouds with respect to coeval star-forming field galaxies. This picture is consistent with the majority of star-forming cluster members infalling in isolation. Upon accretion, star formation is observed to decrease and warm dust is destroyed due to heating from the intracluster medium radiation, ram-pressure stripping, and merger shocks.Peer reviewe

A One-Dimensional Model for Many-Electron Atoms in Extremely Strong Magnetic Fields: Maximum Negative Ionization

We consider a one-dimensional model for many-electron atoms in strong magnetic fields in which the Coulomb potential and interactions are replaced by one-dimensional regularizations associated with the lowest Landau level. For this model we show that the maximum number of electrons is bounded above by 2Z+1 + c sqrt{B}. We follow Lieb's strategy in which convexity plays a critical role. For the case of two electrons and fractional nuclear charge, we also discuss the critical value at which the nuclear charge becomes too weak to bind two electrons.Comment: 23 pages, 5 figures. J. Phys. A: Math and General (in press) 199