Juvenile Hyperlipemia

Asymptomatic hyperlipemia occurs in a significant number of American children. It is important to recognize the condition during childhood because of its role as a risk factor in the early onset of coronary artery disease and because early dietary modification may prevent changes leading to premature heart disease

Giant Antiferromagnetically Coupled Moments in a Molecule-Based Magnet with Interpenetrating Lattices

The molecule-based magnet [Ru$_2$(O$_2$CMe)$_4$]$_3$[Cr(CN)$_6$] contains two weakly-coupled, interpenetrating sublattices in a body-centered cubic structure. Although the field-dependent magnetization indicates a metamagnetic transition from an antiferromagnet to a paramagnet, the hysteresis loop also exhibits a substantial magnetic remanance and coercive field uncharacteristic of a typical metamagnet. We demonstrate that this material behaves like two giant moments with a weak antiferromagnetic coupling and a large energy barrier between the orientations of each moment. Because the sublattice moments only weakly depend on field in the transition region, the magnetic correlation length can be directly estimated from the magnetization.Comment: 3 figure

Zero field splitting, field-dependent magnetization of mixed-valent S = 3/2 Diruthenium(II,III) tetracarboxylates

Journal ArticleThe 2 K field-dependent magnetization, M(H), of S = 3/2 [RunII/III2(OAc)4]+ was studied. [RuII/III 2(OAc)4]+ exhibits an unusually low magnetization with respect to that predicted by the classical Brillouin function. This reduced value is a consequence of the large anisotropy arising from the large zero-field splitting (ZFS), D (+63 ± 11 cm-1), of the [RuII/III2(OAc)4]+ cation, which alters the energy levels with respect to the isotropic energy levels used to derive the Brillouin function. Analytical expressions for the parallel and perpendicular components of M(H) that include zero-field splitting (ZFS), D, and interdimer coupling, 0, are presented for S=3/2. The expression was derived from second-order perturbation theory for \D\>> gUBH. The experimental data fit very well with g = 2.24 ± 0.01, D = +69.5 cm-1 (D/kB = +100 K), and 0 > 0 > -0.6 K indicative of very weak interdimer interactions for both [RuII/III2(OAc)4]Cl and [RuII/III2(OAc)4]3[CoIII(CN)6]

Habitat Use by Different Size Classes of Bowhead Whales in the Central Beaufort Sea during Late Summer and Autumn

The frequency distributions of bowhead whale (Balaena mysticetus) size classes were studied as functions of year, location, water depth, and date. Whales were classified by size and status as calves, small subadults (non-calves < 10 m); large subadults (10–13 m); and adults (> 13 m). Adults include mothers with calves, which were also counted separately. During mid-August to early October of 1982, 1984–86, and 1998–2000, calibrated vertical photography was used to obtain known-scale images of 901 different whales in waters up to 200 m deep between Flaxman and Herschel islands (146? to 139? W) in the central Beaufort Sea. Age composition of the whales photographed over all years of our study was calves 6.2%, small subadults 31.4%, large subadults 33.3%, and adults 29.1%. We found proportionally more subadults and fewer adults than are estimated to be in the overall population, and this result was found both before and after making allowance for reduced effort to obtain photographs early and late in the migration period. Thus parts of the central Beaufort Sea up to 200 m deep appear to be more heavily used by subadult bowheads than by adults in most years. Significant interannual variation existed in length-frequency distributions of whales among years, geographic subdivisions of the study area, water depth categories, and time periods. This variation was due to variable use of the study area by each size class in different years, differences in the water depths used by different size classes, and different migration timing by each size class. In all years, small subadult whales were the dominant group in shallow (< 20 m) nearshore habitats, and the size of the whales increased with increasing water depth. Timing of movements into and through the study area were also related to size class: small subadults arrived first in late August and departed in late September, and adults arrived last in late September. Mothers and calves arrived in early September and were common until at least early October.La répartition des fréquences de la baleine boréale (Balaena mysticetus) en fonction des classes de dimensions a été étudiée à la lumière de critères tels que l’année, l’emplacement, la profondeur de l’eau et la date. Les baleines étaient classées d’après leurs dimensions et leur état, comme suit : baleineaux, petites baleines immatures (non-baleineaux < 10 m); grosses baleines immatures (10–13 m); et baleines adultes (> 13 m). Les adultes comprenaient les mères avec leurs baleineaux, qui étaient aussi comptés séparément. De la mi-août au début octobre 1982, 1984 à 1986 et 1998 à 2000, nous nous sommes servi de photographies verticales calibrées pour obtenir des images d’échelle connue de 901 baleines différentes dans des eaux pouvant atteindre une profondeur de 200 m entre les îles Flaxman et Herschel (146? à 139?O), dans le centre de la mer de Beaufort. La composition par âge des baleines photographiées au cours de toutes les années visées par l’étude s’établissait comme suit : 6,2 % de baleineaux, 31,4 % de petites baleines immatures, 33,3 % de grosses baleines immatures et 29,1 % de baleines adultes. De manière proportionnelle, nous avons repéré plus de baleines immatures et moins de baleines adultes comparativement aux estimations de telles baleines au sein de la population générale, résultat qui a été trouvé tant avant qu’après avoir tenu compte de l’effort réduit pour obtenir des photographies vers le début et vers la fin de la période de migration. Par conséquent, certaines parties du centre de la mer de Beaufort où l’eau atteint une profondeur allant jusqu’à 200 m semblent plus utilisées par les baleines boréales immatures que par les baleines adultes pendant la plupart des années. Par ailleurs, il existait une variation interannuelle importante sur le plan de la répartition des fréquences de longueur des baleines en fonction des années, des subdivisions géographiques de la région à l’étude, des catégories de profondeur de l’eau et des périodes. Cette variation était attribuable à l’utilisation variable de la région visée par l’étude par chaque classe de dimension au cours des différentes années, aux différences de profondeur de l’eau utilisée par les différentes classes de dimension ainsi qu’aux périodes de migration différentes de chaque classe de dimension. Dans le cas de toutes les années, les petites baleines immatures dominaient les habitats peu profonds (< 20 m) en zone côtière, et la taille des baleines augmentait en fonction de la profondeur de l’eau. Le moment des déplacements vers la région à l’étude et dans celle-ci dépendait également de la classe de dimension : les petites baleines immatures arrivaient en premier, vers la fin août et repartaient vers la fin septembre, tandis que les baleines adultes arrivaient en dernier, vers la fin septembre. Les mères et leurs baleineaux arrivaient au début septembre et y restaient au moins jusqu’au début octobre

Thermally isolated deployable shield for spacecraft

A thermally isolated deployable shield for spacecraft is provided utilizing a plurality of lattice panels stowable generally against the craft and deployable to some fixed distance from the craft. The lattice panels are formed from replaceable shield panels affixed to lattice structures. The lattice panels generally encircle the craft providing 360 degree coverage therearound. Actuation means are provided from translating the shield radially outward from the craft and thermally isolating the shield from the craft. The lattice panels are relatively flexible, allowing the shield to deploy to variable diameters while retaining uniform curvature thereof. Restraining means are provided for holding the shield relatively tight in its stowed configuration. Close-out assemblies provide light sealing and protection of the annular spaces between the deployed shield and the crafts end structure

Improvements to a Response Surface Thermal Model for Orion

A study was performed to determine if a Design of Experiments (DOE)/Response Surface Methodology could be applied to on-orbit thermal analysis and produce a set of Response Surface Equations (RSE) that predict Orion vehicle temperatures within 10 F. The study used the Orion Outer Mold Line model. Five separate factors were identified for study: yaw, pitch, roll, beta angle, and the environmental parameters. Twenty-three external Orion components were selected and their minimum and maximum temperatures captured over a period of two orbits. Thus, there are 46 responses. A DOE case matrix of 145 runs was developed. The data from these cases were analyzed to produce a fifth order RSE for each of the temperature responses. For the 145 cases in the DOE matrix, the agreement between the engineering data and the RSE predictions was encouraging with 40 of the 46 RSEs predicting temperatures within the goal band. However, the verification cases showed most responses did not meet the 10 F goal. After reframing the focus of the study to better align the RSE development with the purposes of the model, a set of RSEs for both the minimum and maximum radiator temperatures was produced which predicted the engineering model output within +/-4 F. Therefore, with the correct application of the DOE/RSE methodology, RSEs can be developed that provide analysts a fast and easy way to screen large numbers of environments and assess proposed changes to the RSE factors