Recurrent approach to effective material properties with application to anisotropic binarized random fields

Building on the foundation work of Brown, Milton and Torquato, we present a tractable approach to analyse the effective permittivity of anisotropic two-phase structures. This methodology accounts for successive dipolar interactions, providing a recurrent series expansion of the effective permittivity to arbitrary order. Within this framework, we also demonstrate a progressive method to determine tight bounds that converge towards the exact solution. We illustrate the utility of these methods by using ensemble averaging to determine the micro-structural parameters of anisotropic level-cut Gaussian fields. We find that the depolarization factor of these structures is equivalent to that of an isolated ellipse with the same stretchingratio, and discuss the contribution of the fourth order term to the exact anisotropy

Evaluation of GEOS Total Cloud Fraction with GLOBE Citizen Science Observations and Co-Located Satellite Data

Here we evaluate the total cloud fraction in cycled forecast experiments with the NASA Global Earth Observing System (GEOS) model. Forecasts were run for summer and winter periods of 2017/2018 and compared with ground-based and satellite observations. Citizen science observations from the Global Learning and Observations to Benefit the Environment (GLOBE) Program were matched with MODIS satellite overpasses and geostationary cloud fraction, yielding a dataset of coincident observations for comparison with hourly model output. The observations indicate a model bias toward overcast and clear conditions, with underestimation of intermediate cloud fractions. We investigate underestimation of variance in the sub-grid total water probability density function (PDF) as a possible cause. The PDF determines large-scale cloud fraction as the sub-grid fraction with total water exceeding the saturation specific humidity. We conduct model experiments in which the shape, width, and spatial dependence of the PDF are varied, and consider the impacts on cloud fraction relative to the combined observations

Concentrations of potassium in the serum of selected patients with hay fever

This item was digitized by the Internet Archive. Thesis (Ph.D.)--Boston UniversityStudies in experimental animals and in human beings indicate a marked derangement ot the potassium balance during shock. The plasmapotassium content is found to increase when shock is produced by whatever means such as trauma, hemorrhage, visceral manipulation, drugs, or anaphylactic reactions. This increase in extracellular potassium has its origin in the diffusion of potassium ions from the cells. Moreover, excessive concentrations of potassium ions are injurious to cells and will thereby cause a further depletion of cellular potassium. The roles of potassium in metabolism seem to be: 1/ The chief intracellular base, playing the part within the cell that sodium does in the extracellular fluids; 2/ The maintenance of muscular tone by its balance against the effects of sodium and calcium ions; 3/ Antagonist to insulin and cholinesterase, and as an epinephrinc-like substance. The depletion of intracellular potassium following injury or excessive stimulation of cells makes further stimulation ineffective. However, if the medium surrounding the depleted cell contains available potassium ions, diffusion of this potassium back into the cell results in a recovery of the cell's ability to respond normally to new stimuli. On the basis of the relation of potassium to epinephrine and histamine reactions Rusk and Kenamore suggested the use of potassium salts in the treatment of urticaria. Their '"New Approach" consisted in the use of a high protein, low sodium, acid-ash diet, with the addition of potassium chloride. In 1938 Bloom reported successful palliative treatment of hay fever sufferers by the application of this "New Approach" of Rusk and Kenamore. Various other workers followed this original report with both corroborations and refutations of Bloom's claims. In no case had any of the investigators studied the variations if any, of the serum-potassium content of hay fever patients with reference to incidence of symptoms or type of treatment employed. Because of this dearth of data in regard to patients with hay fever it was deemed advisable to study a series of such people from the point of view of possible variations of the potassium level. The subjects in this series are for the great majority patients at the Allergy Clinic of the Massachusetts Memorial Hospitals. To have comparable conditions, as far as possible, in the individual cases of the series, the study was limited to uncomplicated cases of ragweed hay fever. In this way one could time fairly definitely the onset of exposure to the allergic excitant by checking with the advent of the ragweed pollinating season. The analytical procedure employed is the chloroplatinate micro-method of Consolazio and Talbott. This method was chosen because of its combination of a high degree of precision with a minimal amount of intricate manipulative detail. All analyses were performed in duplicate and occasionally in triplicate or quadruplicate. The median level of potassium for the entire series of forty-one patients is 5.23 milliequivalents per liter (20.42 milligrams per 100 milliliters) of serum. Although this represents only a slight increase over the median for a group of normal controls, statistical analysis of the data shows a definite divergence from normal in the distribution of individual values through the series. Thus the allergic individuals show a greater dispersion of the values of serum-potassium content than that of the normal series, as shown by the greater extent of the Q1 — Q3 interval and by the higher value of the coefficient of dispersion. This tendency toward individual fluctuations is more marked during the ragweed-pollinating season than before the onset of pollination. It is suggested that this fluctuation may represent a relative instability of the mechanism of regulation of potassium balance in the allergic individual as compared to that of the normal. It may also be a manifestation of a subclinical reaction to contact with the atopic excitant

Myanmar's search for normalcy in an abnormal world

For much of the past seventy-plus years since its independence, Myanmar, often known as Burma, was an isolated military dictatorship plagued by seemingly perpetual civil war. Myanmar’s evolution from military dictatorship began in 2010 when a wide-ranging reform process began. While much has changed in the years since, much has not. Myanmar’s transition can best be understood as a “search for normalcy.” Since 2010, the sheer extent of the country’s dysfunction after decades of military dictatorship has overshadowed prospects for change as has the mass exodus of Rohingya in 2017 after a brutal campaign by the military. Amid these quandaries, it is useful to focus on what is feasible for the country in terms of transitioning to what can be understood as “normal”, or at least on a trajectory towards “normalization”. Framing Myanmar’s domestic prospects is also the reality that the last decade has been distinctly abnormal for the whole world. Reform in Myanmar means working methodically to untangle the messy, convoluted knot that is Myanmar’s governance, politics, and economics and being patient throughout the process. All things considered, Myanmar is progressing in important ways that should neither be taken for granted nor forgotten

Reconstitution of Munc18-Dependent Mast Cell Degranulation

Mast cells are specialized secretory leukocytes that play diverse roles in the body, mediated by release of histamine and other pharmacologically active substances. Although offering essential protection in innate and adaptive immunity, mast cells are also essential to the progression of inflammatory diseases, including allergy and asthma, (Theoharides et al., 2012). Exocytosis of pro-inflammatory mast cell mediators in response to otherwise innocuous antigens relies on evolutionarily-conserved membrane fusion machinery. These proteins, called SNAREs are regulated by the Sec1/Munc18 (SM) protein family (Axle Lorentz, Baumann, Vitte, & Blank, 2012). Mast cells express three mammalian Munc18 isoforms (a, b, and c), which are linked to SNARE-dependent exocytosis in numerous organisms. However, the exact roles of each of these Munc18 isoforms in mast cell degranulation have not been clearly defined. In this study we investigated the functional relationship between Munc18 and eight sets of degranulation-relevant SNAREs using in vitro reconstitution. We showed that Munc18a was active in stimulating fusion mediated by VAMP2 and VAMP3, but not by VAMP7 and VAMP8. In contrast, Munc18b and Munc18c did not show any stimulatory activity. Further analysis of Munc18a function unraveled a previously unidentified role in the tethering of SNARE complexes prior to fusion, an action that is dependent on the interaction between Munc18a and N-peptide of syntaxin. Inhibition of fusion and trans-SNARE complex formation by soluble VAMP proteins did not interfere with Munc18a-mediated tethering, indicating that Munc18a-mediated tethering occurs prior to trans-SNARE complex formation. This study therefore sheds light on new roles Munc18 proteins might play to regulate mast cell degranulation

Effective transport properties of conformal Voronoi-bounded columns via recurrent boundary element expansions

Effective transport properties of heterogeneous structures are predicted by geometric microstructural parameters, but these can be difficult to calculate. Here, a boundary element code with a recurrent series method accurately and efficiently determines the high order parameters of polygonal and conformal prisms in regular two-dimensional lattices and Voronoi tessellations (VT). This reveals that proximity to simpler estimates is associated with: centroidal VT (cf random VT), compactness, and VT structures (cf similarly compact semi-regular lattices). An error in previously reported values for triangular lattices is noted

Letter from Matthew Arnold to John Morley

Letter from Matthew Arnold to John Morley, dated June 5th, 1878. In 2014 Philip Kelley, editor of The Brownings’ Correspondence, noted that the text concerns Arnold’s submission of “Irish Catholicism and British Liberalism,” which was published in the July 1878 issue of the Fortnightly.https://scholarworks.umt.edu/whicker/1019/thumbnail.jp

Elastic/plastic analyses of advanced composites investigating the use of the compliant layer concept in reducing residual stresses resulting from processing

High residual stresses within intermetallic and metal matrix composite systems can develop upon cooling from the processing temperature to room temperature due to the coefficient of thermal expansion (CTE) mismatch between the fiber and matrix. As a result, within certain composite systems, radial, circumferential, and/or longitudinal cracks have been observed to form at the fiber-matrix interface. The compliant layer concept (insertion of a compensating interface material between the fiber and matrix) was proposed to reduce or eliminate the residual stress buildup during cooling and thus minimize cracking. The viability of the proposed compliant layer concept is investigated both elastically and elastoplastically. A detailed parametric study was conducted using a unit cell model consisting of three concentric cylinders to determine the required character (i.e., thickness and material properties) of the compliant layer as well as its applicability. The unknown compliant layer mechanical properties were expressed as ratios of the corresponding temperature dependent Ti-24Al-11Nb (a/o) matrix properties. The fiber properties taken were those corresponding to SCS-6 (SiC). Results indicate that the compliant layer can be used to reduce, if not eliminate, radial and circumferential residual stresses within the fiber and matrix and therefore also reduce or eliminate the radial cracking. However, with this decrease in in-plane stresses, one obtains an increase in longitudinal stress, thus potentially initiating longitudinal cracking. Guidelines are given for the selection of a specific compliant material, given a perfectly bonded system