A gravity study in the Amisk Lake area, Saskatchewan

A gravity and density study of a Precambrian greenstone belt has been made near Flin Flon in the Amisk Lake area of Saskatchewan. Approximately 800 gravity stations were read in the three hundred square mile area and 1585 density determinations were made on bedrock samples taken from a one hundred square mile portion of the area. The gravity field and rock densities are strongly correlated with the different rocks which underlie the region. The density variations associated with the outcropping rock units need extend to various depths less than five kilometers to account for all the gravity relief (29 milligals) observed in the area. Below these depths lies a fairly uniform, low density rock with composition possibly approaching that of granite. Surface seismic measurements and well log velocity and density measurements also indicate the existence of low density material at depth. Three new interpretation techniques are presented for the quantitative interpretation of gravity anomalies associated with outcropping rock units. The gravity effect of a right rectangular prism is shown to be directly proportional to its width. This fact has been used to develop a set of characteristic curves which permit the interpretation of the depth to the bottom of such a prism whose top is at zero depth. The expression for the gravity effect of the sloping step model has been used to generate characteristic curves for that model whose top is at zero depth. A mathematical expression has been developed for the gravity effect of a gradational density contrast between two semi-infinite slabs. Type curves and interpretation charts are presented for this model. Fortran IV computer programs which were used in the computations are listed in an appendix. Rock densities were found to depend almost entirely on their mineral content. Porosity of these igneous and metamorphic rocks is negligible and, to the depths considered, pressure and temperature effects are also negligible. The lightest rock is the Phantom Lake granite (2.656 ± .017 gm/cc) and the heaviest is the Ruth Lake meta-gabbro (3.042 ± .066 gm/cc). The mean density of all the samples is 2.862 gm/cc. The gravity interpretation shows the Reynard Lake granodioritic pluton to be sheet-like in its southern part, the depth to the bottom being' about 1000 meters in some places. The northern part of the Mystic Lake granodioritic pluton may be even shallower. The sheet-like portions of the plutons are underlain by basic volcanic or intrusive rock which is in turn underlain by the low density, possibly granitic, rock at depth. Several large basic and ultrabasic dikes and sills lie in a down buckling of Amisk volcanic rocks east of Amisk Lake. This assemblage extends to a maximum depth of almost five kilometers in the southern part of the area and somewhat lesser depths to the north. Elsewhere, rocks of the Amisk group are about three kilometers deep. Several rock units not recognized in the detailed geological mapping have been indicated by the geophysical work. These include a possible fine grained basic intrusion between_Amisk and Mosher Lakes, an acidic intrusion near Denare Beach, a basic intrusion under Comeback Bay and one or more large basic to ultrabasic intrusions extending more than ten miles in the center of Amisk Lake. Some of these interpretations may be interesting from an economic standpoint since both basic intrusions and granodiorite bodies have been thought to be related to ore deposits. In particular, the underside of the sheet-like portions of the granodiorites may be shallow enough to explore with detailed geophysical work and drilling. Also, the existence of previously unrecognized basic intrusions should encourage exploration of these areas with detailed geological and geophysical work and drilling

It is all About Dissimilarity: Party System Characteristics and Their Proper Measurement

In this article we propose a new conceptualization of the crucial party system characteristics: disproportionality, electoral volatility, territorial heterogeneity and inter-election incongruence. We argue that these characteristics can be studied as dissimilarities between vectors of votes or seats. We present different specifications of vectors in order to address various research questions important for students of parties and party systems. Subsequently, developing the analyses of Monroe (1994) and Taagepera and Grofman (2003), we present nine measures of vectors’ dissimilarity: index of dissimilarity, Gallagher’s least squares measure and its transformations, cosine measure, Gini coefficient, Kullback-Leibler divergence (relative entropy), weighted variance and weighted standard deviation of ratios. We discuss their utility in empirical studies of main party system characteristics, using several dimensions of comparison, based on the formal postulates. We also add two new postulates concerning measure’s decomposability: horizontal (sumtype) and vertical (variance-type)

How equal is the electoral representation in municipalities? A study of disproportionality in Polish local councils

The disproportionality is one of the main problems of political representation. Nonetheless, the empirical research on disproportionality in local councils occurs only as an exception. In our paper we demonstrate how disproportionality can be studied at the local level. Following van Puyenbroeck (2008), we distinguish the postulates of “equally treated voters” and “equally treated parties” which are the basis for the assessment of disproportionality. Using the results of recent Polish local elections (2010), we demonstrate how the disproportionality varies between the municipalities of different size, using different electoral formulae, how it is affected by the electoral districting, seat apportionment and local differences in turnout. Moreover, as a preparation for the empirical study of the electoral reform, effective in 2014 (November) elections, we formulate several hypotheses on how the introduction of single-member districts would affect political representation at the local level

Advances in shape measurement in the digital world

The importance of particle shape in terms of its effects on the behaviour of powders and other particulate systems has long been recognised, but particle shape information has been rather difficult to obtain and use until fairly recently, unlike its better-known counterpart, particle size. However, advances in computing power and 3D image acquisition and analysis techniques have resulted in major progress being made in the measurement, description and application of particle shape information in recent years. Because we are now in a digital era, it is fitting that many of these advanced techniques are based on digital technology. This review article aims to trace the development of these new techniques, highlight their contributions to both academic and practical applications, and present a perspective for future developments

Non-partisan Mayors and Their Impact on Local Politics

Artykuł opisuje fenomen bezpartyjności władz lokalnych dużych miast w Polsce, jest sprawozdaniem z badań empirycznych przeprowadzonych we Wrocławiu, w Gdyni i Katowicach. Opisano w nim typowe uzasadnienia bezpartyjności, zidentyfikowano różnice między radnymi partyjnymi a bezpartyjnymi w badanych miastach oraz scharakteryzowano organizacje quasi-partyjne stanowiące polityczne zaplecze bezpartyjnych prezydentów. Badania pokazały, że charakterystyczna dla tych organizacji jest kategoria lokalnych działaczy koncentrujących swoją działalność na szczeblu lokalnym, a także że bezpartyjność może być w polityce lokalnej drogą do instytucjonalizacji szczególnego sposobu rozumienia i uprawiania polityki. Artykuł dowodzi, że problem partyjności i bezpartyjności w polityce lokalnej powinien być rozpatrywany jako część szerszego zagadnienia przenikania się sfer polityki i administracji na poziomie lokalnym.The aim of the article is to describe the phenomenon of non-partisanship of local governments in large Polish cities. It is a report from a research conducted in Wroclaw, Gdynia and Katowice. The article contains a description of typical justifications of non-partisanship, an identification of differences between partisan and non-partisan city councillors and a description of quasi-partisan organizations functioning as political support for non-partisan mayors. The results of the research confirm the existence of a specific category of local activists consistently rejecting party politics and very often having no political ambitions concerning higher levels of government; this category is typical for quasi-partisan organizations. The research demonstrates that non-partisanship can be a means of institutionalization of a particular manner of understanding and making politics. One of the final conclusions is that the problems of partisanship and non-partisanship at the local level are derivatives of a vague relationship between public administration and politics at the local level