Measurement of electron density and temperature in plasmas

Application of two laser wavelengths passing through plasma measures electron density and temperature. Function depends on determining absorption of light at two wavelengths. Nature of reaction is explained and schematic diagram of equipment is included

Density Matrix Renormalization for Model Reduction in Nonlinear Dynamics

We present a novel approach for model reduction of nonlinear dynamical systems based on proper orthogonal decomposition (POD). Our method, derived from Density Matrix Renormalization Group (DMRG), provides a significant reduction in computational effort for the calculation of the reduced system, compared to a POD. The efficiency of the algorithm is tested on the one dimensional Burgers equations and a one dimensional equation of the Fisher type as nonlinear model systems.Comment: 12 pages, 12 figure

Evidence of Erosional Self-Channelization of Pyroclastic Density Currents Revealed by Ground-Penetrating Radar Imaging at Mount St. Helens, Washington (USA)

The causes and effects of erosion are among the least understood aspects of pyroclastic density current (PDC) dynamics. Evidence is especially limited for erosional self-channelization, a process whereby PDCs erode a channel that confines the body of the eroding flow or subsequent flows. We use ground-penetrating radar imaging to trace a large PDC scour and fill from outcrop to its point of inception and discover a second, larger PDC scour and fill. The scours are among the largest PDC erosional features on record, at \u3e200 m wide and at least 500 m long; estimated eroded volumes are on the order of 106 m3. The scours are morphologically similar to incipient channels carved by turbidity currents. Erosion may be promoted by a moderate slope (5–15°), substrate pore pressure retention, and pulses of increased flow energy. These findings are the first direct evidence of erosional self-channelization by PDCs, a phenomenon that may increase flow velocity and runout distance through confinement and substrate erosion

Physiological and morphological responses of 'Irukandji' polyps to thermal and osmotic conditions: consequences for niche profiling

The Irukandji jellyfish (Carukia barnesi) is a medically important species. While the medusa stage of this species is well known, due to its highly venomous sting, the benthic polyp has core roles in regulating both the timing and abundance of medusa making it a research priority. However, due to their small size, Carukia barnesi polyps have never been found in situ and, basic ecological knowledge surrounding this life stage is limited. In this study we adopt a lab-based approach, utilizing physiological tolerance as a functional tool, to gain new insights into the in situ location for Carukia barnesi polyps. The physiological tolerance of Carukia barnesi polyps was characterized by measuring the oxygen consumption rates of polyps exposed to different salinity/temperature combinations. A total of nine salinities and seven temperatures were investigated, ranging from 11 °C/16‰ to 34 °C/42.5‰, encompassing the spectrum of environments experienced on the Great Barrier Reef. Polyps were also monitored for morphological changes such as asexual reproduction, polyp deterioration, and mortality. Salinity did not have a significant effect on oxygen consumption rates, with Carukia barnesi polyps displaying a significant tolerance to a wide range of salinities. The effect of temperature, however, was statistically significant with oxygen °consumption rates increasing alongside water temperature. There was no statistical evidence to support an interactive effect between salinity and temperature. Based on these results, we conclude that the polyp stage of this species is likely located in an environment with stable temperatures and fluctuating salinities and, consequently, future endeavors aimed at locating this life stage should expand targeted survey areas outside stable oceanic environments, typical of medusa, and encompass dynamic environments such as estuaries and submarine freshwater upwellings

The Operophtera brumata Nucleopolyhedrovirus (OpbuNPV) Represents an Early, Divergent Lineage within Genus Alphabaculovirus

Operophtera brumata nucleopolyhedrovirus (OpbuNPV) infects the larvae of the winter moth, Operophtera brumata. As part of an effort to explore the pesticidal potential of OpbuNPV, an isolate of this virus from Massachusetts (USA)—OpbuNPV-MA—was characterized by electron microscopy of OpbuNPV occlusion bodies (OBs) and by sequencing of the viral genome. The OBs of OpbuNPV-MA consisted of irregular polyhedra and contained virions consisting of a single rod-shaped nucleocapsid within each envelope. Presumptive cypovirus OBs were also detected in sections of the OB preparation. The OpbuNPV-MA genome assembly yielded a circular contig of 119,054 bp and was found to contain little genetic variation, with most polymorphisms occurring at a frequency of \u3c 6%. A total of 130 open reading frames (ORFs) were annotated, including the 38 core genes of Baculoviridae, along with five homologous repeat (hr) regions. The results of BLASTp and phylogenetic analysis with selected ORFs indicated that OpbuNPV-MA is not closely related to other alphabaculoviruses. Phylogenies based on concatenated core gene amino acid sequence alignments placed OpbuNPV-MA on a basal branch lying outside other alphabaculovirus clades. These results indicate that OpbuNPV-MA represents a divergent baculovirus lineage that appeared early during the diversification of genus Alphabaculovirus

Management of Gastroesophageal Reflux Disease (GERD) by Primary Care Providers in Mississippi

Gastroesophageal reflux disease (GERD) is one of the most common diseases seen in primary care practice. To reduce the negative effects, such as esophageal narrowing, erosions, and precancerous lesions, from uncontrolled or inadequately managed GERD, primary care providers must stay up to date on evidence-based research and integrate the most current guidelines, The American College of Gastroenterology (ACG) updated guidelines for proper management of GERD in 2021, into practice. The guidelines recommend lifestyle modifications, proper pharmacological treatment with proton pump inhibitors (PPIs) for an eight-week course, and proper follow-up and/or referral if unimproved. The purpose of this research study was to conduct chart reviews of documentation to identify if primary care providers followed current ACG guidelines. After contacting the Mississippi University for Women’s Institutional Review Board and receiving permission to conduct chart reviews at four primary care clinics in Southeastern Mississippi, the current researchers collected data from 465 patients’ charts to assess if current guidelines were being followed by Mississippi primary care providers. The quantitative retrospective study revealed the majority of primary care providers managed GERD adequately, according to current ACG guidelines. Although the data collection initially included all primary care providers, such as nurse practitioners, medical doctors, doctors of osteopathic medicine, and physicians’ assistants, only nurse practitioners and medical doctors were included in the study due to the specific clinics utilized for data collection. Overall, the study revealed nurse practitioners as more compliant than medical doctors with adhering to current ACG guidelines for management of GERD. If Mississippi primary care providers manage GERD according to the ACG guidelines, better patient outcomes can be achieved. By recommending lifestyle modifications, such as weight loss, elevation of the head of bed, refraining from eating two to three hours prior to bedtime, and avoiding trigger foods, reduction of the negative effects of GERD can be piloted. Correct pharmacological treatment with an eight-week course of PPIs can also reduce the negative outcomes produced by GERD without overtreatment that can lead to other issues, like osteoporosis. If failure of combined therapies occur, referral to a specialist should be made for further treatment. The findings also reiterate the importance of timely follow-up. By following the guidelines, primary care providers can improve patient outcomes through reducing the physical strains of GERD and the economical strains of improper management and treatment of the prevalent disease

A corresponding states approach to Small-Angle-Scattering for polydisperse ionic colloidal fluids

Approximate scattering functions for polydisperse ionic colloidal fluids are obtained by a corresponding states approach. This assumes that all pair correlation functions $g_{\alpha \beta}(r)$ of a polydisperse fluid are conformal to those of an appropriate monodisperse binary fluid (reference system) and can be generated from them by scaling transformations. The correspondence law extends to ionic fluids a {\it scaling approximation} (SA) successfully proposed for nonionic colloids in a recent paper. For the primitive model of charged hard spheres in a continuum solvent, the partial structure factors of the monodisperse binary reference system are evaluated by solving the Orstein-Zernike (OZ) integral equations coupled with an approximate closure. The SA is first tested within the mean spherical approximation (MSA) closure, which allows analytical solutions. The results are found in good overall agreement with exact MSA predictions up to relevant polidispersity. The SA is shown to be an improvement over the ``decoupling approximation'' extended to the ionic case. The simplicity of the SA scheme allows its application also when the OZ equations can be solved only numerically. An example is then given by using the hypernetted chain (HNC) closure. Shortcomings of the SA approach, its possible use in the analysis of experimental scattering data and other related points are also briefly addressed.Comment: 29 pages, 7 postscript figures (included), Latex 3.0, uses aps.sty, to appear in Phys. Rev. E (1999

Geomagnetic paleointensity in historical pyroclastic density currents: Testing the effects of emplacement temperature and postemplacement alteration

Thellier-type paleointensity experiments were conducted on welded ash matrix or pumice from the 1912 Novarupta (NV) and 1980 Mt. St. Helens (MSH) pyroclastic density currents (PDCs) with the intention of evaluating their suitability for geomagnetic paleointensity studies. PDCs are common worldwide, but can have complicated thermal and alteration histories. We attempt to address the role that emplacement temperature and postemplacement hydrothermal alteration may play in nonideal paleointensity behavior of PDCs. Results demonstrate two types of nonideal behavior: unstable remanence in multidomain (MD) titanomagnetite, and nonideal behavior linked to fumarolic and vapor phase alteration. Emplacement temperature indirectly influences MSH results by controlling the fraction of homogenous MD versus oxyexsolved pseudo-single domain titanomagnetite. NV samples are more directly influenced by vapor phase alteration. The majority of NV samples show distinct two-slope behavior in the natural remanent magnetization—partial thermal remanent magnetization plots. We interpret this to arise from a (thermo)chemical remanent magnetization associated with vapor phase alteration, and samples with high water content (\u3e0.75% loss on ignition) generate paleointensities that deviate most strongly from the true value. We find that PDCs can be productively used for paleointensity, but that—as with all paleointensity studies—care should be taken in identifying potential postemplacement alteration below the Curie temperature, and that large, welded flows may be more alteration-prone. One advantage in using PDCs is that they typically have greater areal (spatial) exposure than a basalt flow, allowing for more extensive sampling and better assessment of errors and uncertainty