Cryptorchism, hypogonadism and antler malformations in black-tailed deer(Odocoileus hemionus sitkensis) of Kodiak island

Summary Distinct antler malformations, (such as lack of points, distortion of antler forms, incomplete velvet shedding, casting above the coronet and a diagonal separation of cast antlers), were detected in Sitka deer(Odocoileus hemionus sitkensis) of the Kodiak Island (Alaska, USA). Many of these deer were also unilateral or bilateral cryptorchids and a few exhibited a moderate or severe separation of frontal skull bones. Radioimmunoassay analyses of serum revealed signs of hypogonadism: we found higher concentrations of LH (P=0.05) and lower concentrations of T (P=0.037) in bilateral cryptorchids as compared to intact bucks. There was no apparent impairment of spermatogenesis in the remaining testis of the unilateral cryptorchid deer. Unfortunately, no ectopic testes were so far recovered in cryptorchid deer. Surprisingly, only about half of deer with bilateral cryptorchism exhibited hypogonadic symptoms. In the other half of cryptorchid deer, the antlers appeared completely normal and the concentrations of LH or testosterone in the serum of several bucks were in the range of intact deer. It has been postulated that in some cryptorchid deer, ectopic testes can produce sufficient amount of testosterone, which prevents obvious antler and skull malformations, as well as reduces the compensatory elevation of LH. The possible causes of the hypogonadism resulting in cryptorchism and antler malformations are discussed.Eingesetzt wurde ein Druckkostenzuschuss des Hessischen Ministeriums für Umwelt, Landwirtschaft und Forsten, für dessen Gewährung verbindlich gedankt wird. — Die Schriftleitung     

High-Temperature Stability of Alumina in Argon and Argon/Water-Vapor Environments

The high-temperature stability of alumina (Al₂O₃) in argon and argon/water-vapor (Ar/H₂O) environments has been investigated. Samples were exposed at temperatures of 1300°C–1700°C for 10 h. The microstructure, flexural strength, and volume all showed significant changes in the Ar/H₂O environment at 1700°C. Samples also became whiter, because of the oxidation of graphite impurities that had diffused from the hot-processing dies. In the Ar/H₂O environment at 1700°C, grain-boundary etching occurred and was much more severe than in the pure-argon environment, which was very likely caused by the enhanced formation of gaseous Al(OH)₃ and Al(OH)₂ along grain boundaries. In addition, in the Ar/H₂O environment, substantial grain growth occurred in the surface vicinity. This grain growth, together with grain-boundary etching, led to a decrease in flexural strength.     

Degradation of Nextel™ 610‐based oxide‐oxide ceramic composites by aluminum oxychloride decomposition products

Nextel? 610 alumina fibers and alumina‐YAG (yttrium‐aluminum garnet) matrices were used to make oxide‐oxide ceramic matrix composites (CMCs) with and without monazite (LaPO₄) fiber‐matrix interfaces. Twelve sequential aluminum oxychloride (AlOCl) infiltrations with 1 hour heat treatments at 1100°C and a final 1 hour heat treatment at 1200°C were used for matrix densification. This matrix processing sequence severely degraded CMC mechanical properties. CMC tensile strengths and interlaminar tensile (ILT) strengths were less than 10 MPa and 1 MPa, respectively. Axial fracture of Nextel? 610 fibers was observed after ILT testing, highlighting the extreme degradation of fiber strength. Extensive characterization was done to attempt to determine the responsible degradation mechanisms. Changes in Nextel? 610 fiber microstructure after CMC processing were characterized by optical microscopy, SEM, and extensively by TEM. In AlOCl degraded fibers, grain boundaries near the fiber surface were wetted with a glass that contained Y₂O₃/SiO₂ or Y₂O₃/La₂O₃/P₂O₅/SiO₂, and near‐surface pores were partially filled with Al₂O₃. This glass must also contain some Al₂O₃ and initially some chlorine. AlOCl decomposition products were predicted using the FactSage^® Thermochemical code, and were characterized by mass spectrometry. Effects of AlOCl precursors on monazite coated and uncoated Nextel? 610 fibers tow and filament strength were evaluated. A mechanism for the severe degradation of the oxide‐oxide CMCs and Nextel? 610 fibers that involves subcritical crack growth promoted by release of chlorine containing species during breakdown of intergranular glasses in an anhydrous environment is proposed.     

EFFECTS OF FLOW DYNAMICS ON THE AQUATIC‐TERRESTRIAL TRANSITION ZONE (ATTZ) OF LOWER MISSOURI RIVER SANDBARS WITH IMPLICATIONS FOR SELECTED BIOTA

Sandbars are an important aquatic terrestrial transition zone (ATTZ) in the active channel of rivers that provide a variety of habitat conditions for riverine biota. Channelization and flow regulation in many large rivers have diminished sandbar habitats and their rehabilitation is a priority. We developed sandbar‐specific models of discharge‐area relationships to determine how changes in flow regime affect the area of different habitat types within the submerged sandbar ATTZ (depth) and exposed sandbar ATTZ (elevation) for a representative sample of Lower Missouri River sandbars. We defined six different structural habitat types within the sandbar ATTZ based on depth or exposed elevation ranges that are important to different biota during at least part of their annual cycle for either survival or reproduction. Scenarios included the modelled natural flow regime, current managed flow regime and two environmental flow options, all modelled within the contemporary river active channel. Thirteen point and wing‐dike sandbars were evaluated under four different flow scenarios to explore the effects of flow regime on seasonal habitat availability for foraging of migratory shorebirds and wading birds, nesting of softshell turtles and nursery of riverine fishes. Managed flows provided more foraging habitat for shorebirds and wading birds and more nursery habitat for riverine fishes within the channelized reach sandbar ATTZ than the natural flow regime or modelled environmental flows. Reduced summer flows occurring under natural and environmental flow alternatives increased exposed sandbar nesting habitat for softshell turtle hatchling emergence. Results reveal how management of channelized and flow regulated large rivers could benefit from a modelling framework that couples hydrologic and geomorphic characteristics to predict habitat conditions for a variety of biota. Published in 2011 by John Wiley & Sons, Ltd.     

UML的前途

UML（统一建模语言）成为标准已经超过12年了。在这些年里，人们对UML的看法各不相同，有喜爱的，也有讨厌的。在这篇文章中，我们将讨论当前UML规范的不足之处．并建议如何让它敏捷、更精益、更智慧、更有弹性——简而言之，     

Synthesis and Structures of A Series of Novel Rare Earth Transition Metal Sulfates

Seven new rare earth transition metal sulfates were synthesized by hydrothermal reactions under conditions slightly above the critical point of water. Their crystal structures were determined from single crystal X-ray data. The compositions of the new compounds can be represented by two general formulae ： REM （OH） 3 （SO4） and RE2M （OH） 3 （SO4） 2F （H2O） with RE = Gd, Tb, Dy ; M = Ni, Cu. Three different crystal structure types were found for the formula REM （OH） 3 （SO4）. The structures of the new compounds all feature infinite chains of REOn coordination polyhedra, which are connected to chains of CuO6 or NiO6 octabedra. The limited size range of the rare earth cations observed in these compounds is most likely because of interactions between the octabedral chains and the chains of REOn polyhedra. The new compounds are closely related to the known yttrium transition metal sulfates.     

Effect of microstructure on oxygen permeation in SrCo0.8Fe0.2O3−δ

The effect of microstructure on oxygen permeation in SrCo0.8Fe0.2O3– membranes was investigated using disc samples fabricated under different processing conditions of applied pressure and sintering temperature. The average grain size of the samples was found to remain unchanged as a function of applied pressure, but increased considerably when the sintering temperature was increased from 950 to 1200°C. This change in grain size has a strong effect on the oxygen permeation flux, which increased considerably as the grain size was decreased. The density as well as the microhardness of these samples were also measured and found to change slightly as the processing conditions were changed.