Large Solutions of Semilinear Elliptic Equations with Nonlinear Gradient Terms

We show that large positive solutions exist for the equation ( P ± ) : Δ u ± | ∇ u | q = p ( x ) u γ in Ω ⫅ R N ( N ≥ 3 ) for appropriate choices of γ \u3e 1 , q \u3e 0 in which the domain Ω is either bounded or equal to R N . The nonnegative function p is continuous and may vanish on large parts of Ω . If Ω = R N , then p must satisfy a decay condition as | x | → ∞ . For ( P + ) , the decay condition is simply ∫ 0 ∞ t ϕ ( t ) d t \u3c ∞ , where ϕ ( t ) = max | x | = t p ( x ) . For ( P − ) , we require that t 2 + β ϕ ( t ) be bounded above for some positive β . Furthermore, we show that the given conditions on γ and p are nearly optimal for equation ( P + ) in that no large solutions exist if either γ ≤ 1 or the function p has compact support in Ω

Selective parent ion axialization for improved efficiency of collision-induced dissociation in laser desorption-ionization Fourier transform ion cyclotron resonance mass spectrometry

AbstractWe have systematically established the excitation frequency, amplitude, duration, and buffer gas pressure for optimal axialization efficiency and mass selectivity of quadrupolar excitation-collisional cooling for isolation of parent ions for collision-induced dissociation in Fourier transform ion cyclotron resonance mass spectrometry. For example, at high quadrupolar excitation amplitude, ion axialization efficiency and selectivity are optimal when the applied quadrupolar excitation frequency is lower than the unperturbed ion cyclotron frequency by up to several hundred hertz. Moreover, at high buffer gas pressure (10−6 Torr), quadrupolar excitation duration can be quite short because of efficient collisional cooling of the cyclotron motion produced by magnetron-to-cyclotron conversion. Efficiency, detected signal magnitude, and mass resolving power for collision-induced dissociation (CID) product ions are significantly enhanced by prior parent ion axilization. With this method, we use argon CID to show that C+94 (m/z 1128) formed by Nd:YAG laser desorption-ionization behaves as a closed-cage structure

River Basin Surveys Papers, No. 34: The Demery Site (39C01), Oahe Reservoir Area, South Dakota

Published as a series sponsored by the Smithsonian Institution Bureau of American Ethnology, the “River Basin Surveys Papers” are a collection of archeological investigations focused on areas now flooded by the completion of various dam projects in the United States. The River Basin Surveys Papers (numbered 1-39) were mostly published in bundles, with 5-6 papers in each bundle. In collaboration with the United States (US) National Park Service and the US Bureau of Reclamation, the US Department of the Interior, and the US Army Corps of Engineers, the Smithsonian Institution pulled archeological and paleontological remains from several sites prior to losing access to the sites due to flooding. The Smithsonian Institution calls this project the Inter-Agency Archeological Salvage Program. Paper number 34 discusses the excavation of the Demery Site, located on the west bank of the Missouri River, near John Grass Creek (named for chief John Grass also known as Matȟó Watȟákpe or Charging Bear, of the Blackfeet band of Lakota). The site was excavated in 1956, by members of the State Historical Society of North Dakota. The excavation was sponsored by the National Park Service, the Department of the Interior, and the North Dakota State Legislator. The Standing Rock Nation Tribal Council granted permission for the site to be excavated. Excavation of the site yielded several houses, pottery, plant and animal remains, The site yielded artifacts made from chipped stone, ground stone, antler, and shell. Ancestors (human remains) were also found at the site. The authors do not posit what group(s) lived at this site but note that they likely lived there peacefully judging by the lack of fortifications. The authors estimate that the area was occupied between 1550 and 1650 A.D. This paper contains photographs, illustrations, text figures, and maps.https://commons.und.edu/indigenous-gov-docs/1127/thumbnail.jp

Novel approaches to the development and assessment of an ovine model of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common reproductive, endocrine and metabolic disorder present in women of reproductive age. Despite the widespread prevalence and heritability of PCOS, the heterogeneous and polygenic traits have made the successful identification of candidate genes difficult. Animal models have been developed on the premise that early exposure to sex steroids can programme epigenetic changes that predispose the fetus to the adult features of PCOS. Past research has modelled ovarian dysfunction, endocrine abnormalities and metabolic perturbances in rodent, non-human primate and sheep PCOS models, through the enhanced neonatal or prenatal exposure to the male sex hormone, testosterone. The modelling of PCOS in a large domestic species such as the sheep is advantageous due to similar biological reproductive function as the human. In this regard the sheep has been extensively used to model PCOS by the treatment of pregnant ewes from early to midgestation with androgens such as testosterone propionate (TP). These experiments have demonstrated the fetal programming effects of androgens on offspring that go on to develop PCOS-like characteristics in adulthood. One of the caveats of assessing steroid effects in this way is the effect of the placenta in mediating the transfer of these hormones. TP is an aromatisable androgen and thus some of its effects in the fetus may be attributable to placental by-products such as estrogens. This thesis describes the development and assessment of a novel model of prenatal androgenisation. Two models were compared: the indirect maternal exposure to TP (the current model) and the direct fetal injection of TP. In directly treating the fetus this allowed control over the dose of TP administered and avoidance of secondary effects that androgens may exert in the mother that could be transferred to the fetus. For the maternal model, pregnant Scottish Greyface ewes were administered TP twice weekly from day (d)62-102 of a 147 day gestation. For the fetal model, fetuses were injected twice while the ewe was anaesthetised with graded doses of TP during the same period of treatment as the maternal model. The effects of prenatal androgenisation were assessed in the female fetus shortly after treatment and also in young adult sheep. Fetal ovarian and adrenal steroidogenic gene expression was monitored and found to be altered in response to elevated levels of sex steroids. At d90 the morphology of the developing ovary was not changed by prenatal androgens. In the adult a detailed ovarian and endocrine assessment was undertaken, by examination of ovarian morphology, hormone levels, ovulatory cycles, hypothalamic pituitary ovarian function and follicle steroidogenesis, during the first breeding season. In addition, the metabolic effects of prenatal androgens were monitored by measuring body fat, insulin and glucose homeostasis and liver function. Neither maternal nor fetal prenatal androgenisation during mid-gestation resulted in a perturbed hormonal milieu or polycystic ovaries in young adults. These treatments did however programme a clear ovarian phenotype demonstrated by the increased capacity of follicles to secrete androgens, independently of an abnormal endocrine environment and disordered folliculogenesis. Furthermore, animals that were exposed maternally to TP developed fatty liver and had increased insulin secretion in response to glucose load. A major outcome of this study was the finding that the fetally injected control animals were phenotypically different than the maternal control animals. In fact, some of the reproductive and metabolic features of maternal TP exposure were found in the fetal control group. This unexpected finding has raised the possibility that it is the fetal exposure to stress, that is secondary to elevated maternal androgens, rather than androgens per se that is responsible for at least some of the multitude of anomalies encountered in PCOS

Fluidized Bed Polymer Particle ALD Process for Producing HDPE/Alumina Nanocomposites

Micron-sized High Density Polyethylene (HDPE) particles were coated with ultrathin alumina (Al2O3) films in a Fluidized Bed Reactor (FBR) by Atomic Layer Deposition (ALD) at 77 ºC. Al2O3 films on the HDPE particles were confirmed by different methods. These particles were extruded conventionally with the ceramic shells mixing intimately in the polymer matrix. The successful dispersion of the Al2O3 shells in the polymer matrix following extrusion was confirmed using cross sectional Transmission Electron Microscopy (TEM)

Ice-lens formation and geometrical supercooling in soils and other colloidal materials

We present a new, physically-intuitive model of ice-lens formation and growth during the freezing of soils and other dense, particulate suspensions. Motivated by experimental evidence, we consider the growth of an ice-filled crack in a freezing soil. At low temperatures, ice in the crack exerts large pressures on the crack walls that will eventually cause the crack to split open. We show that the crack will then propagate across the soil to form a new lens. The process is controlled by two factors: the cohesion of the soil, and the geometrical supercooling of the water in the soil; a new concept introduced to measure the energy available to form a new ice lens. When the supercooling exceeds a critical amount (proportional to the cohesive strength of the soil) a new ice lens forms. This condition for ice-lens formation and growth does not appeal to any ad hoc, empirical assumptions, and explains how periodic ice lenses can form with or without the presence of a frozen fringe. The proposed mechanism is in good agreement with experiments, in particular explaining ice-lens pattern formation, and surges in heave rate associated with the growth of new lenses. Importantly for systems with no frozen fringe, ice-lens formation and frost heave can be predicted given only the unfrozen properties of the soil. We use our theory to estimate ice-lens growth temperatures obtaining quantitative agreement with the limited experimental data that is currently available. Finally we suggest experiments that might be performed in order to verify this theory in more detail. The theory is generalizable to complex natural-soil scenarios, and should therefore be useful in the prediction of macroscopic frost heave rates.Comment: Submitted to PR

Reproducibility of Serologic Assays for Influenza Virus A (H5N1)

Results for clade 1 viruses were more consistent among laboratories when a standard antibody was used

How many species of fungi are there at the tip of Africa?

Several recent studies have reviewed the extent of fungal biodiversity, and have used these data as basis for revised estimates of species numbers based on known numbers of plants and insects. None of these studies, however, have focused on fungal biodiversity in South Africa. Coinciding with the 100th anniversary of the National Collection of Fungi (PREM) in South Africa in 2005, it is thus timely to reflect on the taxonomic research that has been conducted in South Africa over the past Century. Information is presented on the extent of fungal collections preserved at PREM, and the associated research publications that have largely resulted from this resource. These data are placed in context of the known plant and insect biodiversity, and used as basis to estimate the potential number of fungi that could be expected in South Africa. The conservative estimate is of approximately 200 000 species without taking into account those associated with a substantial insect biodiversity