Thoria doped with cations of group VB–synthesis and sintering

The cations M⁵⁺ (M=V, Nb and Ta) were doped in thoria through gel-combustion synthesis using citric acid as fuel. Thorium dioxide feed powders thus prepared were cold compacted without binder or lubricant and sintered to a high density (9.5 Mg m⁻³) at relatively low temperatures (1623 K). The powders were characterised for the residual carbon, crystallite size, specific surface area, particle size distribution and bulk density. The distribution of the dopant in the thoria matrix was analyzed by electron probe microanalysis. The reactivity of the calcined powders was determined by measuring the density of the sintered compacts prepared from them. For the first time it is demonstrated that apart from niobia, even tantala and vanadia can bring about accelerated sintering in thoria if they are doped through a wet chemical route viz., the gel-combustion procedure. The maximum densities obtained by doping with vanadia (0.02 mol%), niobia (0.50 mol%) and tantala (0.50 mol%) were 9.8 Mg m⁻³ (1573 K), 9.68 Mg m⁻³ (1423 K) and 9.69 Mg m⁻³ (1623 K), respectively.     

Effects of estrogen-induced hyperlipidemia on the erythrocyte membrane in chicks

The effects of estrogen-induced hyperlipidemia on plasma lipid peroxidation, fatty acid composition and osmotic fragility of erythrocytes in chickens were studied. Young male chickens implanted with estrogen for three wk developed a marked hyperlipidemia. Plasma levels of triglyceride, cholesterol and phospholipid were elevated 68-, four- and 24-fold, respectively, over controls. There was also a two-fold increase in plasma lipid peroxidation measured by the thiobarbituric acid test. Vitamin E supplement (1,000 IU/kg diet) reduced the plasma lipid peroxidation to the control level, but had no effect on the plasma lipid content. Estrogen-induced hyperlipidemia resulted in changes in the fatty acid composition of membrane lipids of erythrocytes. The major changes were an increase in oleic acid from 10.0% to 14.2% and a decrease in linoleic acid from 31.3% to 26.0%. The erytrocytes with an altered membrane fatty acid composition were found to have an increased osmotic fragility. It was apparent that there was a direct correlation between the oleic acid content and the osmotic fragility of erythrocytes.     

Management Systems: Four Options,One Solution

Integrated technology cannot be an objective in itself. Instead, organizations should use the integration of their technologies to further their business objectives.     

Tributary confluences are dynamic thermal refuges for a juvenile salmonid in a warming river network

As rivers warm, cold‐water fish species may alleviate thermal stress by moving into localized thermal refuges such as cold‐water plumes created by cool tributary inflows. We quantified use of two tributary confluence plumes by juvenile steelhead, Oncorhynchus mykiss, throughout the summer, including how trout positioned themselves in relation to temperature within confluence plumes. At two confluences, Cedar and Elder creeks, along the South Fork Eel River, California, USA, we monitored temperatures using in situ logger grids throughout summer 2016. Fish were counted within confluences via snorkel surveys five times a day on 5 days at each site. We found diel and seasonal dependence on confluence use by steelhead, especially at the Cedar Creek confluence, where mainstem temperatures exceeded 28°C. At this site, fish moved into the confluence on the warmest days and warmest times of the day. Fish observed within the Cedar Creek confluence plume were most common in locations between 20–22°C, rather than the coldest locations (14.5°C). At Elder Creek, where mainstem temperatures remained below 24°C, there was little relationship between mainstem temperature and steelhead presence in the confluence plume. At both sites, steelhead distribution within plumes was influenced by spatial variation of temperature and mean temperature in surveyed grid cells. Our results show that cool tributaries flowing into warmer mainstem reaches (over 24°C) likely create important thermal refuges for juvenile steelhead. As mainstem rivers warm with climate change, cool‐water tributary inputs may become more important for sustaining cold‐water salmonids near the southern end of their range.     

Modeling Uncertainty in an Object-Oriented Reservoir Operations Model

In recent years, reservoir management considerations have expanded to include environmental and recreational objectives, many of which are often difficult to quantify. With a larger set of operational objectives comes the need to identify tradeoffs and uncertainties among the various objectives. Uncertainty modeling may contribute to better reservoir management by identifying and quantifying the sources of significant uncertainty in predicting reservoir and river conditions that affect environmental habitats and recreational conditions. We implement a first-order, second-moment algorithm in RIVERWARE, an object-oriented river and reservoir modeling environment. The method is developed and applied to a case study from the lower Colorado River, where a preexisting deterministic model is used for reservoir operations and planning. The case study involves evaluation of uncertainties associated with prescribed reservoir pool elevations for purposes of recovering endangered fish species. Comparison of historical forecasts with observed data can provide managers with insight into operational policies that result in greater system uncertainty. Identifying these sources of uncertainty can guide managers in the development of future operational guidelines.     

Endometriosis and the neoplastic process

Endometriosis is a frequent disorder that commonly presents with infertility and pelvic pain. Although the precise aetiology of endometriosis is unclear, it is generally considered to involve multiple genetic, environmental, immunological, angiogenic and endocrine processes. Genetic factors have been implicated in endometriosis but the susceptibility genes remain largely unknown. Although endometriosis is a benign disorder, recent studies of endometriosis suggest endometriosis could be viewed as a neoplastic process. Evidence to support this hypothesis includes the increased susceptibility to develop ovarian clear-cell and endometrioid cancers in the presence of endometriosis, and molecular similarities between endometriosis and cancer. In this article we discuss (i) the evidence suggesting that endometriosis might be viewed as a neoplastic process, and (ii) the implications of this hypothesis for elucidating the pathogenesis of endometriosis and developing novel methods of diagnostic classification and individualised treatments.     

Theoretical study on strain-induced variations in electronic properties of monolayer MoS2

Ultrathin MoS₂ sheets and nanostructures are promising materials for electronic and optoelectronic devices as well as chemical catalysts. To expand their potential in applications, a fundamental understanding is needed of the electronic structure and carrier mobility as a function of strain. In this paper, the effect of strain on electronic properties of monolayer MoS₂ is investigated using ab initio simulations based on density functional theory. Our calculations are performed in both infinitely large two-dimensional (2D) sheets and one-dimensional (1D) nanoribbons which are theoretically cut from the sheets with semiconducting \( [\bar{1}100] \) (armchair) edges. The 2D crystal is studied under biaxial strain, uniaxial strain, and uniaxial stress conditions, while the 1D nanoribbon is studied under a uniaxial stress condition. Our results suggest that the electronic bandgap of the 2D sheet experiences a direct-indirect transition under both tensile and compressive strains. Its bandgap energy (E _g) decreases under tensile strain/stress conditions, while for an in-plane compression, E _g is initially raised by a small amount and then decreased as the strain varies from 0 to ?6 %. On the other hand, E _g at the semiconducting edges of monolayer MoS₂ nanoribbons is relatively invariant under uniaxial stretches or compressions. The effective masses of electrons at the conduction band minimum (CBM) and holes at the valence band maximum (VBM) are generally decreased as the in-plane extensions or compressions become stronger, but abrupt changes occur when CBM or VBM shifts between different k-points in the first Brillouin zone.     

Watershed and River Systems Management Program: Overview of Capabilities

Beginning in January 1992, the Bureau of Reclamation (Reclamation) and the US Geological Survey (USGS) formulated plans for the Watershed and River Systems Management Program—a cooperative interagency effort to develop and implement flexible and robust river basin management tools for the benefit of managers and decision makers using a data centered approach. In addition to Reclamation and the USGS, a number of other agencies and universities have made substantial contributions to the success of the program. The result has been the need driven research and development of state-of-the-art technology which benefits water managers and technical specialists in many river basins.     

Separation of Reflection Components Using Color and Polarization

Specular reflections and interreflections produce strong highlights in brightness images. These highlights can cause vision algorithms for segmentation, shape from shading, binocular stereo, and motion estimation to produce erroneous results. A technique is developed for separating the specular and diffuse components of reflection from images. The approach is to use color and polarization information, simultaneously, to obtain constraints on the reflection components at each image point. Polarization yields local and independent estimates of the color of specular reflection. The result is a linear subspace in color space in which the local diffuse component must lie. This subspace constraint is applied to neighboring image points to determine the diffuse component. In contrast to previous separation algorithms, the proposed method can handle highlights on surfaces with substantial texture, smoothly varying diffuse reflectance, and varying material properties. The separation algorithm is applied to several complex scenes with textured objects and strong interreflections. The separation results are then used to solve three problems pertinent to visual perception; determining illumination color, estimating illumination direction, and shape recovery.     

Synchrony of net nitrogen mineralization and maize nitrogen uptake following applications of composted and fresh swine manure in the Midwest U.S.

Understanding how the quality of organic soil amendments affects the synchrony of nitrogen (N) mineralization and plant N uptake is critical for optimal agronomic N management and environmental protection. Composting solid livestock manures prior to soil application has been promoted to increase N synchrony; however, few field tests of this concept have been documented. Two years of replicated field trials were conducted near Boone, Iowa to determine the effect of composted versus fresh solid swine manure (a mixture of crop residue and swine urine and feces produced in hoop structures) on Zea mays (maize) N uptake, in situ soil net N mineralization, and soil inorganic N dynamics. Soil applications of composted manure increased maize N accumulation by 25?% in 2000 and 21?% in 2001 compared with fresh manure applications (application rate of 340?kg?N?ha^?1). Despite significant differences in net N mineralization between years, within year seasonal total in situ net N mineralization was similar for composted and fresh manure applications. Partial N budgets indicated that changes in soil N pools (net N mineralization and soil inorganic N) in the surface 20?cm accounted for 67?% of the total plant N accumulation in 2000 but only 16?% in 2001. Inter-annual variation in maize N accumulation could not be attributed to soil N availability. Overall, our results suggest that composting manures prior to soil application has no clear benefit for N synchrony in maize crops. Further work is required to determine the biotic and abiotic factors underlying this result.