Vacuum forming of thermoplastic sheet results in low-cost investment casting patterns

Vacuum forming of a sheet of thermoplastic material around a mandrel conforming to the shape of the finished object provides a pattern for an investment mold. The thickness of the metal part is determined by the thickness of the plastic pattern

Earth-Moon trajectories, 1965-70

Analytical model for generation of earth-moon trajectory analysis dat

The role of proton precipitation in Jovian aurora: Theory and observation

It was proposed that the Jovian auroral emissions observed by Voyager spacecraft could be explained by energetic protons precipitating into the upper atmosphere of Jupiter. Such precipitation of energetic protons results in Doppler-shifted Lyman alpha emission that can be quantitatively analyzed to determine the energy flux and energy distribution of the incoming particle beam. Modeling of the expected emission from a reasonably chosen Voyager energetic proton spectrum can be used in conjunction with International Ultraviolet Explorer (IUE) observations, which show a relative lack of red-shifted Lyman alpha emission, to set upper limits on the amount of proton precipitation taking place in the Jovian aurora. Such calculations indicate that less than 10 percent of the ultraviolet auroral emissions at Jupiter can be explained by proton precipitation

Learning a Static Analyzer from Data

To be practically useful, modern static analyzers must precisely model the effect of both, statements in the programming language as well as frameworks used by the program under analysis. While important, manually addressing these challenges is difficult for at least two reasons: (i) the effects on the overall analysis can be non-trivial, and (ii) as the size and complexity of modern libraries increase, so is the number of cases the analysis must handle. In this paper we present a new, automated approach for creating static analyzers: instead of manually providing the various inference rules of the analyzer, the key idea is to learn these rules from a dataset of programs. Our method consists of two ingredients: (i) a synthesis algorithm capable of learning a candidate analyzer from a given dataset, and (ii) a counter-example guided learning procedure which generates new programs beyond those in the initial dataset, critical for discovering corner cases and ensuring the learned analysis generalizes to unseen programs. We implemented and instantiated our approach to the task of learning JavaScript static analysis rules for a subset of points-to analysis and for allocation sites analysis. These are challenging yet important problems that have received significant research attention. We show that our approach is effective: our system automatically discovered practical and useful inference rules for many cases that are tricky to manually identify and are missed by state-of-the-art, manually tuned analyzers

The Mid-Late Holocene Evolution of Southern Walland Marsh and the Origin of the ‘Midley Sand’

This paper documents new litho-, bio- and chronostratigraphic information and sedimentological data from sites at Sandyland on Broomhill Level, Midley and Lydd. These locations are situated between former tidal inlets at Romney and Rye which were instrumental in driving Foreland and Marshland environmental change during the last 2000 years. Peat formation commenced c. 4500 cal. yr BP at Sandyland and after 3700 cal. yr BP at Lydd. At Sandyland, eutrophic fen carr communities were replaced by acidic, nutrient-poor Myrica-dominated vegetation from c. 4100 cal. yr BP, a shift reported from other sites on Walland Marsh and from neighbouring areas. At Lydd, there was no local development of Myrica, probably due to the proximity of the site to tidal channels associated with an opening in the barrier at Hythe. Inundation occurred sometime after c. 2300 cal. yr BP at both sites although the upper contacts of the peat are sharp and have probably been eroded. The sedimentological investigations of the surface outcrops of ‘Midley Sand’ at Sandyland and Midley, combined with other stratigraphic and palaeogeographic evidence, are consistent with deposition in a tidal channel. The data support the existence of an open-ended channel connecting the inlets at Romney and Rye between AD 700 and the 12th century AD, which had already begun to infill and become reclaimed prior to the storms of the 13th century AD. The Wainway Channel appears to be a later feature which developed in the area after the closure of the Romney inlet and enlargement of the Rye inlet as a result of these storms

Earth - venus trajectories, 1968-69, volume 4, part b

Earth-venus trajectories 1968-196

Disorder drives cooperative folding in a multidomain protein

Many human proteins contain intrinsically disordered regions, and disorder in these proteins can be fundamental to their function - for example, facilitating transient but specific binding, promoting allostery, or allowing efficient posttranslational modification. SasG, a multidomain protein implicated in host colonization and biofilm formation in Staphylococcus aureus, provides another example of how disorder can play an important role. Approximately one-half of the domains in the extracellular repetitive region of SasG are intrinsically unfolded in isolation, but these E domains fold in the context of their neighboring folded G5 domains. We have previously shown that the intrinsic disorder of the E domains mediates long-range cooperativity between nonneighboring G5 domains, allowing SasG to form a long, rod-like, mechanically strong structure. Here, we show that the disorder of the E domains coupled with the remarkable stability of the interdomain interface result in cooperative folding kinetics across long distances. Formation of a small structural nucleus at one end of the molecule results in rapid structure formation over a distance of 10 nm, which is likely to be important for the maintenance of the structural integrity of SasG. Moreover, if this normal folding nucleus is disrupted by mutation, the interdomain interface is sufficiently stable to drive the folding of adjacent E and G5 domains along a parallel folding pathway, thus maintaining cooperative folding

The Bacteroidales produce an N-acylated derivative of glycine with both cholesterol-solubilising and hemolytic activity.

The contribution of the gut microbiota to the metabolism of cholesterol is not well understood. In this study, we identify 21 fosmid clones from a human gut microbiome metagenomic library that, when expressed in Escherichia coli, produce halos on LB agar supplemented with 0.01% (w/v) cholesterol (LBC agar). Analysis of 14 of these clones revealed that they all share a fragment of DNA with homology to the genome of Bacteroides vulgatus. The gene responsible for halo production on LBC agar, named choA, was identified as an N-acyltransferase known to produce an acylated glycine molecule called commendamide. In this study we show that commendamide is capable of producing a halo on LBC agar suggesting that this molecule is solubilizing the cholesterol micelles in LBC agar. We also show that commendamide is responsible for the previously described hemolytic activity associated with the choA orthologue in Bacteroides fragilis. A functional analysis of ChoA identified 2 amino acids that are important for commendamide biosynthesis and we present phylogenetic and functional data showing that orthologues of choA are found only in the order Bacteroidales. Therefore, the production of commendamide may be an adaptation to the environments colonized by the Bacteroidales, including the mammalian gut

Hemispheric solution of the Omega equation including terrain and surface frictional effects

A quasi-geostrophic omega equation for large-scale vertical velocities in the atmosphere is solved at the earth's surface, 850 mb, 700 mb, 500 mb, and 300 mb for a grid of 1977 points per level covering the major portion of the Northern Hemisphere. The effects of terrain and surface frictional stress on the vertical velocity at the lower boundary are investigated in some detail and applied at the earth's surface. The three-dimensional integration of the resulting equations excludes areas "inside" the terrain. The mathematical model is programmed for the Control Data Corporation 1604 digital computer to utilize the operational output of machine processed data and analyses produced by the Fleet Numerical Weather Facility (FNWF), Monterey, California. the program allows a wide variety of modes of operation and yields a solution for w in five minutes. An unusual weather situation in January, 1962 is investigated and the results, although tentative, show that the correlation between computer vertical velocities and the observed weather is excellent.http://www.archive.org/details/hemisphericsolut00clarCommander, United States Naval ReserveLieutenant, United States NavyApproved for public release; distribution is unlimited

Automatic Abstraction for Congruences

One approach to verifying bit-twiddling algorithms is to derive invariants between the bits that constitute the variables of a program. Such invariants can often be described with systems of congruences where in each equation $\vec{c} \cdot \vec{x} = d \mod m$, (unknown variable m)$is a power of two,$\vec{c}$is a vector of integer coefficients, and$\vec{x}$ is a vector of propositional variables (bits). Because of the low-level nature of these invariants and the large number of bits that are involved, it is important that the transfer functions can be derived automatically. We address this problem, showing how an analysis for bit-level congruence relationships can be decoupled into two parts: (1) a SAT-based abstraction (compilation) step which can be automated, and (2) an interpretation step that requires no SAT-solving. We exploit triangular matrix forms to derive transfer functions efficiently, even in the presence of large numbers of bits. Finally we propose program transformations that improve the analysis results