Continuous-flow electrophoresis: Membrane-associated deviations of buffer pH and conductivity

The deviations in buffer pH and conductivity which occur near the electrode membranes in continuous-flow electrophoresis were studied in the Beckman charged particle electrophoresis system and the Hanning FF-5 preparative electrophoresis instrument. The nature of the membranes separating the electrode compartments from the electrophoresis chamber, the electric field strength, and the flow rate of electrophoresis buffer were all found to influence the formation of the pH and conductivity gradients. Variations in electrode buffer flow rate and the time of electrophoresis were less important. The results obtained supported the hypothesis that a combination of Donnan membrane effects and the differing ionic mobilities in the electrophoresis buffer was responsible for the formation of the gradients. The significance of the results for the design and stable operation of continuous-flow electrophoresis apparatus was discussed

Differential cross-section for positronium formation in electron-atomic hydrogen collisions

The L=0 and 1 partial wave amplitudes obtained by a two-state coupled static approximation with correlation with the L greater than or equal to 2 Born amplitudes were combined to obtain the differential cross section for positronium formation in electron-atomic hydrogen collisions. For positron energies of 0.64 and 0.75 ryd, minima at the scattering angles of 57 deg and 51 deg are found. Total cross sections for positronium formation for low and intermediate impact energies are given. Measurement of the differential cross section for the process positron + helium yields positronium + helium ion for the detection of possible minima is suggested

Distribution of cogenetic iron and clay deposits in the central Appalachian region

Maps of more than 500 abandoned iron mines, 350 early iron furnaces, and numerous clay mines in the central part of the Appalachian region reveal the distribution and close association of siderite-limonite bearing ores and clay deposits. The deposits crop out from Lancaster County, Pennsylvania to Scioto County, Ohio, a distance of more than 300 miles. The geologic settings of the deposits are diverse. In the Valley and Ridge Province and Piedmont Province, mineralization follows structures such as major sub-horizontal thrust faults (e.g. Martic) and steep thrust faults, (e. g. Path Valley), that juxtapose carbonate units against other rocks. Carbonate units within the Plateau Province also contain economic deposits of iron ores and clay. The ores are commonly siderite and limonite principally in the form of nodules and other irregular masses in clayey, calcareous beds. Illite and kaolinite are the main clay minerals. Silica is a common constituent of the clayey rocks and in some of the iron-rich, ore horizons (e.g. Buhrstone). The working hypothesis for the formation of the iron ore and clay is that reactive fluids probably moved westward along structural and stratigraphic horizons in response to tectonic events and where they encounter carbonate rocks, clay formed and iron precipitated under favorable geochemical conditions. This hypothesis differs from other ideas such as weathering and consequent development of leached paleosols, and bog iron formation. Modern models of iron deposition are based on shallow groundwater transporting iron to the precipitation site. The possible outflow of basinal fluids along deep thrust faults and cross strike discontinuities was considered as an alternative process for iron deposition and clay formation

Many-body system with a four-parameter family of point interactions in one dimension

We consider a four-parameter family of point interactions in one dimension. This family is a generalization of the usual $\delta$-function potential. We examine a system consisting of many particles of equal masses that are interacting pairwise through such a generalized point interaction. We follow McGuire who obtained exact solutions for the system when the interaction is the $\delta$-function potential. We find exact bound states with the four-parameter family. For the scattering problem, however, we have not been so successful. This is because, as we point out, the condition of no diffraction that is crucial in McGuire's method is not satisfied except when the four-parameter family is essentially reduced to the $\delta$-function potential.Comment: 8 pages, 4 figure

Exploration Medical Cap Ability System Engineering Overview

Deep Space Gateway and Transport missions will change the way NASA currently practices medicine. The missions will require more autonomous capability compared to current low Earth orbit operations. For the medical system, lack of consumable resupply, evacuation opportunities, and real-time ground support are key drivers toward greater autonomy. Recognition of the limited mission and vehicle resources available to carry out exploration missions motivates the Exploration Medical Capability (ExMC) Element's approach to enabling the necessary autonomy. The ExMC Systems Engineering team's mission is to "Define, develop, validate, and manage the technical system design needed to implement exploration medical capabilities for Mars and test the design in a progression of proving grounds." The Element's work must integrate with the overall exploration mission and vehicle design efforts to successfully provide exploration medical capabilities. ExMC is using Model-Based System Engineering (MBSE) to accomplish its integrative goals. The MBSE approach to medical system design offers a paradigm shift toward greater integration between vehicle and the medical system, and directly supports the transition of Earth-reliant ISS operations to the Earth-independent operations envisioned for Mars. This talk will discuss how ExMC is using MBSE to define operational needs, decompose requirements and architecture, and identify medical capabilities needed to support human exploration. How MBSE is being used to integrate across disciplines and NASA Centers will also be described. The medical system being discussed in this talk is one system within larger habitat systems. Data generated within the medical system will be inputs to other systems and vice versa. This talk will also describe the next steps in model development that include: modeling the different systems that comprise the larger system and interact with the medical system, understanding how the various systems work together, and developing tools to support trade studies

Revising Mary Queen of Scots: from Protestant Persecution to Patriarchal Struggle

Since Mary Queen of Scots’ execution in 1587, she has become a symbol of Scottish identity, failed female leadership, and Catholic martyrdom. Throughout the twentieth century, Mary was regularly depicted on screen (Ford, 1936; Froelich, 1940; Jarrott, 1971) as a thrice-wed Catholic queen, unable to rule her country due to her feminine nature and Catholic roots. However, with the rise of third wave feminism and postfeminism in media, coupled with the increased influence of female directors and writers, Mary’s characterization has shifted from portraying female/emotional weakness and religious sacrifice to female/collaborative strength in hardship and a struggle against patriarchal prejudice. Josie Rourke’s film Mary Queen of Scots (2018) and CW’s Reign (2013-2017) present a queen who is no longer limited to her religious identity as a Catholic martyr, and consequently a weak ruler. Instead religious division is mostly sidelined, and gendered politics is the central struggle, highlighting similarities between Mary and Queen Elizabeth I of England, where previous films presented opposites. Together, these two productions transform Mary’s narrative from fragility and religion, into a struggle against misogynistic control of powerful women

Evaluation of large area crop estimation techniques using LANDSAT and ground-derived data

The results of the Domestic Crops and Land Cover Classification and Clustering study on large area crop estimation using LANDSAT and ground truth data are reported. The current crop area estimation approach of the Economics and Statistics Service of the U.S. Department of Agriculture was evaluated in terms of the factors that are likely to influence the bias and variance of the estimator. Also, alternative procedures involving replacements for the clustering algorithm, the classifier, or the regression model used in the original U.S. Department of Agriculture procedures were investigated