Rapid billet loader aids extrusion of refractory metals

A combination gravity and manually powered rapid billet loader reduces the time required for transferring hot metal billets from a heating furnace to an extrusion press. Positioned between the furnace and extrusion press, this loader is a simple slide-delivery device

On the reality of the Venus winds

The Venera measurements of wind speed along with the Mariner measurements of lower-region of strong turbulence are evidence for a wide band of variable high speed retrograde horizontal winds which girdle Venus at the equator. In one interpretation of the Mariner 10 UV photographs, the 20km region above the top of the visible cloud is characterized by variable high-speed retrograde horizontal winds which orbit Venus with an average period of 4 earth days, and by many features indicating vertical convection. This suggests that the Venera-Mariner band of winds at 45km extends to the top of the UV cloud and beyond, and that the upper-region of strong turbulence detected by the Mariners may result from vertical convection currents carried along by high speed horizontal winds. In another interpretation, the predominate motions are attributed to wavelike disturbances with a 4-day period. For this case the upper-region of strong turbulence may be due in large part to vertical wind-shear resulting from a rapid decrease in wind speed within a relatively short distance about the Venera-Mariner band of high speed winds

Sulfur-house operation /

C38

Optical Dielectric Functions of III-V Semiconductors in Wurtzite Phase

Optical properties of semiconductors can exhibit strong polarization dependence due to crystalline anisotropy. A number of recent experiments have shown that the photoluminescence intensity in free standing nanowires is polarization dependent. One contribution to this effect is the anisotropy of the dielectric function due to the fact that most nanowires crystalize in the wurtzite form. While little is known experimentally about the band structures wurtzite phase III-V semiconductors, we have previously predicted the bulk band structure of nine III-V semiconductors in wurtzite phase.Here, we predict the frequency dependent dielectric functions for nine non-Nitride wurtzite phase III-V semiconductors (AlP, AlAs, AlSb, GaP, GaAs, GaSb, InP, InAs and InSb). Their complex dielectric functions are calculated in the dipole approximation by evaluating the momentum matrix elements on a dense grid of special k-points using empirical pseudopotential wave functions. Corrections to the momentum matrix elements accounting for the missing core states are made using a scaling factor which is determined by using the optical sum rules on the calculated dielectric functions for the zincblende polytypes. The dielectric function is calculated for polarizations perpendicular and parallel to the c-axis of the crystal

Sun-drying fruits

C39

EBF1-deficient bone marrow stroma elicits persistent changes in HSC potential

Crosstalk between mesenchymal stromal cells (MSCs) and hematopoietic stem cells (HSCs) is essential for hematopoietic homeostasis and lineage output. Here, we investigate how transcriptional changes in bone marrow (BM) MSCs result in long-lasting effects on HSCs. Single-cell analysis of Cxcl12-abundant reticular (CAR) cells and PDGFRα+Sca1+ (PαS) cells revealed an extensive cellular heterogeneity but uniform expression of the transcription factor gene Ebf1. Conditional deletion of Ebf1 in these MSCs altered their cellular composition, chromatin structure and gene expression profiles, including the reduced expression of adhesion-related genes. Functionally, the stromal-specific Ebf1 inactivation results in impaired adhesion of HSCs, leading to reduced quiescence and diminished myeloid output. Most notably, HSCs residing in the Ebf1-deficient niche underwent changes in their cellular composition and chromatin structure that persist in serial transplantations. Thus, genetic alterations in the BM niche lead to long-term functional changes of HSCs

LA MEMORIA DE UN TERRITORIO. TUNJA Y SUS 475 AÑOS HISPÁNICOS

El concepto de territorio se ha sabido construir y de construir desde las ciencias sociales, la intangibilidad del espacio es una característica novedosa y que ubica este concepto en un eje de análisis que va más allá de lo material, por ello los territorios son construcciones sociales, resultado de un nivel de apropiación por parte de unas comunidades, compuestas por redes y por actores, estas interacciones se dan en función del tiempo. Un territorio se debe a la memoria, y este es un concepto que se abordará desde diferentes posturas, Maurice Hallbwachs (Marcos sociales), Aby Warburg (Memoria visual), Pierre Nora (Lugares de la memoria) y Aleida y Jan Assmann (Memoria Cultural). De tal manera que se logre comprender claramente las maneras como se reproduce la memoria y a partir de ellos determinar estrategias que permitan conmemorar los 475 años de la ciudad de Tunja

An analysis of the Venera 8 measurements

Analysis of the Venera 8 measurements yielded equatorial morning terminator horizontal and vertical winds which are similar to the winds obtained from the Venera 7 measurements. The lower boundary of the horizontal retrograde 4-day wind is defined by a 50-60% decrease in wind speed in the vicinity of 44 km and there exists a retrograde wind plateau of 15 to 40 m/s winds extending from 40 km down to the vicinity of 18 km where the winds decrease rapidly to the order of 0.1 m/s near the surface. Up drafts of 2 to 5 m/s exist in the vicinity of 20 to 30 km and are apparently associated with a slightly super adiabatic lapse rate. The temperature lapse-rate, surface radius, surface topography, and atmospheric structure are discussed