The Right to Bear Arms : Two Views

The authors provide varying opinions on the Second Amendment

Ultimate gravitational mass defect

We present a new type of gravitational mass defect in which an infinite amount of matter may be bounded in a zero ADM mass. This interpolates between effects typical of closed worlds and T-spheres. We consider the Tolman model of dust distribution and show that this phenomenon reveals itself for a solution that has no origin on one side but is closed on the other side. The second class of examples corresponds to smooth gluing T-spheres to the portion of the Friedmann-Robertson-Walker solution. The procedure is generalized to combinations of smoothly connected T-spheres, FRW and Schwarzschild metrics. In particular, in this approach a finite T-sphere is obtained that looks for observers in two R-regions as the Schwarzschild metric with two different masses one of which may vanish.Comment: 9 pages. 1 reference added. To appear in Gen. Rel. Gra

Multi-layered Ruthenium-modified Bond Coats for Thermal Barrier Coatings

Diffusional approaches for fabrication of multi-layered Ru-modified bond coats for thermal barrier coatings have been developed via low activity chemical vapor deposition and high activity pack aluminization. Both processes yield bond coats comprising two distinct B2 layers, based on NiAl and RuAl, however, the position of these layers relative to the bond coat surface is reversed when switching processes. The structural evolution of each coating at various stages of the fabrication process has been and subsequent cyclic oxidation is presented, and the relevant interdiffusion and phase equilibria issues in are discussed. Evaluation of the oxidation behavior of these Ru-modified bond coat structures reveals that each B2 interlayer arrangement leads to the formation of α-Al 2 O 3 TGO at 1100°C, but the durability of the TGO is somewhat different and in need of further improvement in both cases

Carbon release from submarine seeps at the Costa Rica fore arc: implications for the volatile cycle at the Central America convergent margin

We report total dissolved inorganic carbon (DIC) abundances and isotope ratios, as well as helium isotope ratios (3He/4He), of cold seep fluids sampled at the Costa Rica fore arc in order to evaluate the extent of carbon loss from the submarine segment of the Central America convergent margin. Seep fluids were collected over a 12 month period at Mound 11, Mound 12, and Jaco Scar using copper tubing attached to submarine flux meters operating in continuous pumping mode. The fluids show minimum 3He/4He ratios of 1.3 RA (where RA is air 3He/4He), consistent with a small but discernable contribution of mantle-derived helium. At Mound 11, δ13C∑CO2 values between −23.9‰ and −11.6‰ indicate that DIC is predominantly derived from deep methanogenesis and is carried to the surface by fluids derived from sediments of the subducting slab. In contrast, at Mound 12, most of the ascending dissolved methane is oxidized due to lower flow rates, giving extremely low δ13C∑CO2 values ranging from −68.2‰ to −60.3‰. We estimate that the carbon flux (CO2 plus methane) through submarine fluid venting at the outer fore arc is 8.0 × 105 g C km−1 yr−1, which is virtually negligible compared to the total sedimentary carbon input to the margin and the output at the volcanic front. Unless there is a significant but hitherto unidentified carbon flux at the inner fore arc, the implication is that most of the carbon being subducted in Costa Rica must be transferred to the (deeper) mantle, i.e., beyond the depth of arc magma generation

Genome-edited zebrafish model of ABCC8 loss-of-function disease

ATP-sensitive potassium channel (

Structural equation modeling of food craving across the menstrual cycle T using behavioral, neuroendocrine, and metabolic factors

Objective: To identify associations between circulating endocannabinoids and craving during the luteal phase of the menstrual cycle. This report is a secondary analysis of a trial registered in clinicaltrials.gov as NCT01407692. Methods: Seventeen premenopausal women were studied during the follicular and luteal phases of their menstrual cycle. Previously we had reported fasting plasma estradiol, progesterone, leptin associations with luteal phase cravings for carbohydrate, fat, sweet-rich foods, and eating behavior. Here, we measured fasting plasma endocannabinoids (ECs) endocannabinoid-like substances (ECLs), and postprandial metabolic responses to a mixed meal challenge. Structural equation modeling was used to evaluate relationships between measured variables and cravings. Results: Oleoylethanolamide (OEA) and postprandial lipids were inversely associated with craving sweet-rich foods, while progesterone was positively associated (RMSEA = 0.041, χ2 p: 0.416 i.e. hypothetical and physiological models not different). OEA, progesterone and disinhibition were positively associated with craving carbohydrates (RMSEA: \u3c 0.001, χ2 p: 0.919). ECs and ECLs combined were stronger predictors of craving than clinical metabolic parameters, ECs only, satiety hormones or gonadocorticoids. Conclusions: Our theoretical model suggests that ECs and ECLs influence craving. Since these metabolites can be modulated via dietary fat intake, they could be potential targets to alter menstrual cycle cravings

Correlating tephras and cryptotephras using glass compositional analyses and numerical and statistical methods:Review and evaluation

We define tephras and cryptotephras and their components (mainly ash-sized particles of glass ± crystals in distal deposits) and summarize the basis of tephrochronology as a chronostratigraphic correlational and dating tool for palaeoenvironmental, geological, and archaeological research. We then document and appraise recent advances in analytical methods used to determine the major, minor, and trace elements of individual glass shards from tephra or cryptotephra deposits to aid their correlation and application. Protocols developed recently for the electron probe microanalysis of major elements in individual glass shards help to improve data quality and standardize reporting procedures. A narrow electron beam (diameter ~3-5 μm) can now be used to analyze smaller glass shards than previously attainable. Reliable analyses of ‘microshards’ (defined here as glass shards <32 µm in diameter) using narrow beams are useful for fine-grained samples from distal or ultra-distal geographic locations, and for vesicular or microlite-rich glass shards or small melt inclusions. Caveats apply, however, in the microprobe analysis of very small microshards (<=~5 µm in diameter), where particle geometry becomes important, and of microlite-rich glass shards where the potential problem of secondary fluorescence across phase boundaries needs to be recognised. Trace element analyses of individual glass shards using laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS), with crater diameters of 20 μm and 10 μm, are now effectively routine, giving detection limits well below 1 ppm. Smaller ablation craters (<10 μm) can be subject to significant element fractionation during analysis, but the systematic relationship of such fractionation with glass composition suggests that analyses for some elements at these resolutions may be quantifiable. In undertaking analyses, either by microprobe or LA-ICP-MS, reference material data acquired using the same procedure, and preferably from the same analytical session, should be presented alongside new analytical data. In part 2 of the review, we describe, critically assess, and recommend ways in which tephras or cryptotephras can be correlated (in conjunction with other information) using numerical or statistical analyses of compositional data. Statistical methods provide a less subjective means of dealing with analytical data pertaining to tephra components (usually glass or crystals/phenocrysts) than heuristic alternatives. They enable a better understanding of relationships among the data from multiple viewpoints to be developed and help quantify the degree of uncertainty in establishing correlations. In common with other scientific hypothesis testing, it is easier to infer using such analysis that two or more tephras are different rather than the same. Adding stratigraphic, chronological, spatial, or palaeoenvironmental data (i.e. multiple criteria) is usually necessary and allows for more robust correlations to be made. A two-stage approach is useful, the first focussed on differences in the mean composition of samples, or their range, which can be visualised graphically via scatterplot matrices or bivariate plots coupled with the use of statistical tools such as distance measures, similarity coefficients, hierarchical cluster analysis (informed by distance measures or similarity or cophenetic coefficients), and principal components analysis (PCA). Some statistical methods (cluster analysis, discriminant analysis) are referred to as ‘machine learning’ in the computing literature. The second stage examines sample variance and the degree of compositional similarity so that sample equivalence or otherwise can be established on a statistical basis. This stage may involve discriminant function analysis (DFA), support vector machines (SVMs), canonical variates analysis (CVA), and ANOVA or MANOVA (or its two-sample special case, the Hotelling two-sample T² test). Randomization tests can be used where distributional assumptions such as multivariate normality underlying parametric tests are doubtful. Compositional data may be transformed and scaled before being subjected to multivariate statistical procedures including calculation of distance matrices, hierarchical cluster analysis, and PCA. Such transformations may make the assumption of multivariate normality more appropriate. A sequential procedure using Mahalanobis distance and the Hotelling two-sample T² test is illustrated using glass major element data from trachytic to phonolitic Kenyan tephras. All these methods require a broad range of high-quality compositional data which can be used to compare ‘unknowns’ with reference (training) sets that are sufficiently complete to account for all possible correlatives, including tephras with heterogeneous glasses that contain multiple compositional groups. Currently, incomplete databases are tending to limit correlation efficacy. The development of an open, online global database to facilitate progress towards integrated, high-quality tephrostratigraphic frameworks for different regions is encouraged