Physical Properties of Deep Drill Cores : Implications for Meteorite Impact Effects and Crustal Structures

Physical properties provide valuable information about the nature and behavior of rocks and minerals. The changes in rock physical properties generate petrophysical contrasts between various lithologies, for example, between shocked and unshocked rocks in meteorite impact structures or between various lithologies in the crust. These contrasts may cause distinct geophysical anomalies, which are often diagnostic to their primary cause (impact, tectonism, etc). This information is vital to understand the fundamental Earth processes, such as impact cratering and associated crustal deformations. However, most of the present day knowledge of changes in rock physical properties is limited due to a lack of petrophysical data of subsurface samples, especially for meteorite impact structures, since they are often buried under post-impact lithologies or eroded. In order to explore the uppermost crust, deep drillings are required. This dissertation is based on the deep drill core data from three impact structures: (i) the Bosumtwi impact structure (diameter 10.5 km, 1.07 Ma age; Ghana), (ii) the Chesapeake Bay impact structure (85 km, 35 Ma; Virginia, U.S.A.), and (iii) the Chicxulub impact structure (180 km, 65 Ma; Mexico). These drill cores have yielded all basic lithologies associated with impact craters such as post-impact lithologies, impact rocks including suevites and breccias, as well as fractured and unfractured target rocks. The fourth study case of this dissertation deals with the data of the Paleoproterozoic Outokumpu area (Finland), as a non-impact crustal case, where a deep drilling through an economically important ophiolite complex was carried out. The focus in all four cases was to combine results of basic petrophysical studies of relevant rocks of these crustal structures in order to identify and characterize various lithologies by their physical properties and, in this way, to provide new input data for geophysical modellings. Furthermore, the rock magnetic and paleomagnetic properties of three impact structures, combined with basic petrophysics, were used to acquire insight into the impact generated changes in rocks and their magnetic minerals, in order to better understand the influence of impact. The obtained petrophysical data outline the various lithologies and divide rocks into four domains. Based on target lithology the physical properties of the unshocked target rocks are controlled by mineral composition or fabric, particularly porosity in sedimentary rocks, while sediments result from diverse sedimentation and diagenesis processes. The impact rocks, such as breccias and suevites, strongly reflect the impact formation mechanism and are distinguishable from the other lithologies by their density, porosity and magnetic properties. The numerous shock features resulting from melting, brecciation and fracturing of the target rocks, can be seen in the changes of physical properties. These features include an increase in porosity and subsequent decrease in density in impact derived units, either an increase or a decrease in magnetic properties (depending on a specific case), as well as large heterogeneity in physical properties. In few cases a slight gradual downward decrease in porosity, as a shock-induced fracturing, was observed. Coupled with rock magnetic studies, the impact generated changes in magnetic fraction the shock-induced magnetic grain size reduction, hydrothermal- or melting-related magnetic mineral alteration, shock demagnetization and shock- or temperature-related remagnetization can be seen. The Outokumpu drill core shows varying velocities throughout the drill core depending on the microcracking and sample conditions. This is similar to observations by Kern et al., (2009), who also reported the velocity dependence on anisotropy. The physical properties are also used to explain the distinct crustal reflectors as observed in seismic reflection studies in the Outokumpu area. According to the seismic velocity data, the interfaces between the diopside-tremolite skarn layer and either serpentinite, mica schist or black schist are causing the strong seismic reflectivities.

Successive refinement of structures with data of increasing resolution: a theoretical study for triclinic space groups

The method of least squares could be used to refine an imperfectly related trial structure by adoption of one of the following two procedures: (i) using all the observed at one time or (ii) successive refinement in stages with data of increasing resolution. While the former procedure is successful in the case of trial structures which are sufficiently accurate, only the latter has been found to be successful when the mean positional error (i.e.<|[Delta]r|>) for the atoms in the trial structure is large. This paper makes a theoretical study of the variation of the R index, mean phase-angle error, etc. as a function of <|[Delta]r|> for data corresponding to different esolutions in order to find the best refinement procedure [i.e. (i) or (ii)] which could be successfully employed for refining trial structures in which <|[Delta]r|> has large, medium and low values. It is found that a trial structure for which the mean positional error is large could be refined only by the method of successive refinement with data of increasing resolution.

Mixed Azide and 5-(Pyrimidyl)tetrazole Bridged Co(II)/Mn(II) Polymers: Synthesis, Crystal Structures, Ferroelectric and Magnetic Behavior

The reaction of pyrimidine-2-carbonitrile, NaN3 in the presence of Co(NO3)(2)center dot 6H(2)O or MnCl2 center dot 4H(2)O leads to the formation of complexes Co(pmtz)(mu(1,3)-N-3)(H2O)](n) (1) and Mn(pmtz)(mu(1,3)-N-3)(H2O)](n) (2) respectively, under hydrothermal condition pmtz =5-(pyrimidyl)tetrazolate]. These two complexes have been fully characterized by single crystal X-ray diffraction. Complex 1 crystallizes in a non-centrosymmetric space group Aba2 in the orthorhombic system and is found to exhibit ferroelectric behavior, whereas complex 2 crystallizes in the P2(1)/c space group in the monoclinic system. Variable temperature magnetic characterizations in the temperature range of 2-300 K indicate that complex 1 is a canted antiferromagnet (weak ferromagnet) with T-c = 15.9 K. Complex 1 represents a unique example of a multiferroic coordination polymer containing tetrazole as a co-ligand. Complex 2 is a one-dimensional chain of Mn(II) bridged by a well-known antiferromagnetic coupler end-to-end azido ligand. In contrast to the role played by the end-to-end azido pathway in most of the transition metal complexes, complex 2 showed unusual ferromagnetic behavior below 40 K because of spin canting.

Artificial Bee Colony (ABC) for multi-objective design optimization of composite structures

In this paper, we present a generic method/model for multi-objective design optimization of laminated composite components, based on Vector Evaluated Artificial Bee Colony (VEABC) algorithm. VEABC is a parallel vector evaluated type, swarm intelligence multi-objective variant of the Artificial Bee Colony algorithm (ABC). In the current work a modified version of VEABC algorithm for discrete variables has been developed and implemented successfully for the multi-objective design optimization of composites. The problem is formulated with multiple objectives of minimizing weight and the total cost of the composite component to achieve a specified strength. The primary optimization variables are the number of layers, its stacking sequence (the orientation of the layers) and thickness of each layer. The classical lamination theory is utilized to determine the stresses in the component and the design is evaluated based on three failure criteria: failure mechanism based failure criteria, maximum stress failure criteria and the tsai-wu failure criteria. The optimization method is validated for a number of different loading configurations-uniaxial, biaxial and bending loads. The design optimization has been carried for both variable stacking sequences, as well fixed standard stacking schemes and a comparative study of the different design configurations evolved has been presented. Finally the performance is evaluated in comparison with other nature inspired techniques which includes Particle Swarm Optimization (PSO), Artificial Immune System (AIS) and Genetic Algorithm (GA). The performance of ABC is at par with that of PSO, AIS and GA for all the loading configurations. (C) 2009 Elsevier B.V. All rights reserved.

Interaction of water molecules in non-identical protein structures

The interaction of the protein atoms with the surrounding water oxygen atoms has been computed for 392 protein chains from 369 protein structures belonging to 90% non-homologous high resolution (<= 1.5 angstrom) protein Structures with a crystallographic R-factor <= 20%. The percentage composition of the polar atoms is found to be 36.3%. An average of 82.55% of water oxygen atoms are found to be in the primary hydration shell and 15.12% in the secondary hydration shell. The average Percentage of interactions of water oxygen atoms with the polar atoms of the main chain and side chain are 54% and 46%. respectively. The interaction of the acidic residues, aspartate and glutamate, with the water oxygen atoms is more when compared to that of the other residues.

Structure-Reactivity Correlations of Benzoin Alkyl Ethers. Structures of 2-Methoxy-1,2-diphenylethanone (I) and 2-Isopropoxy-1,2-diphenylethanone (II)

(I): C15H1402, Mr---226.27, triclinic, Pi,a=8.441 (2), b= 10.276 (1), c= 15.342 (2)A, a=91.02 (2), ~ t= 79.26 (2), y= 105.88 (2) °, V=1256.8 (4)A 3, Z=4, D,,= 1.209 (flotation in KI),D x - 1.195 g cm -3, #(Mo, 2 = 0.7107/~) = 0.44 cm -~,F(000) = 480, T= 293 K, R -- 0.060 for 1793 significant reflections. (II): C~THlsO2, Mr= 254.83, orthorhombic, Pca21, a=8.476 (1); b= 16.098 (3), c=10.802(3)A, V=1473.9 (5) A s, Z=4, Dm=1.161 (flotation in KI), Dx= 1.148gem -3, /~(Mo, 2=0.7107 A) =0.41 cm -~, F(000) = 544, T= 293 K, R = 0.071 for 867 significant reflections. Both (I) and (II) crystallize in a cisoid conformation for the carbonyl group and alkoxy groups. Compounds (I) and (II) are photostable on irradiation in the solid state in spite of the favourable conformation of the functional groups for intramolecular H abstraction. Absence of photoreaction of (I)and (II) in the solid state is rationalized in the light of unfavourable intramolecular geometry.

From Habits to Social Structures : Pragmatism and Contemporary Social Theory

Pragmatism has sometimes been taken as a catchphrase for epistemological stances in which anything goes. However, other authors argue that the real novelty and contribution of this tradition has to do with its view of action as the context in which all things human take place. Thus, it is action rather than, for example, discourses that should be our starting point in social theory. The introductory section of the book situates pragmatism (especially the ideas of G. H. Mead and John Dewey) within the field and tradition of social theory. This introductory also contextualizes the main core of the book which consists of four chapters. Two of these chapters have been published as articles in scientific journals and one in an edited book. All of them discuss the core problem of social theory: how is action related to social structures (and vice versa)? The argument is that habitual action is the explanation for the emergence of social structures from our action. Action produces structures and social reproduction takes place when action is habitualized; that is, when we develop social dispositions to act in a certain manner in familiar environments. This also means that even though the physical environment is the same for all of us, our habits structure it into different kinds of action possibilities. Each chapter highlights these general insights from different angles. Practice theory has gained momentum in recent years and it has many commonalities with pragmatism because both highlight the situated and corporeal character of human activity. One famous proponent of practice theory is Margaret Archer who has argued that the pragmatism of G. H. Mead leads to an oversocialized conception of selfhood. Mead does indeed present a socialized view of selfhood but this is a meta-sociological argument rather than a substantial sociological claim. Accordingly, one can argue that in this general sense intersubjectivity precedes subjectivity and not the other way around. Such a view does not indicate that our social relation would necessarily "colonize" individual action because there is a place for internal conversations (in Archer s terminology); it is especially in those phases of action where it meets obstacles due to the changes of the environment. The second issue discussed has the background assumption that social structures can fruitfully be conceptualized as institutions. A general classification of different institution theories is presented and it is argued that there is a need for a habitual theory of institutions due to the problems associated with these other theories. So-called habitual institutionalism accounts for institutions in terms of established and prevalent social dispositions that structure our social interactions. The germs of this institution theory can be found in the work of Thorstein Veblen. Since Veblen s times, these ideas have been discussed for example, by the economist Geoffrey M. Hodgson. His ideas on the evolution of institutions are presented but a critical stance is taken towards his tendency of defining institutions with the help of rules because rules are not always present in institutions. Accordingly, habitual action is the most basic but by no means the only aspect of institutional reproduction. The third chapter deals with theme of action and structures in the context of Pierre Bourdieu s thought. Bourdieu s term habitus refers to a system of dispositions which structure social fields. It is argued that habits come close to the concept of habitus in the sense that the latter consists of particular kinds of habits; those that are related to the reproduction of socioeconomic positions. Habits are thus constituents of a general theory of societal reproduction whereas habitus is a systematic combination of socioeconomic habits. The fourth theme relates to issues of social change and development. The capabilities approach has been associated with the name of Amartya Sen, for example, and it underscores problems inhering in economistic ways of evaluating social development. However, Sen s argument has some theoretical problems. For example, his theory cannot adequately confront the problem of relativism. In addition, Sen s discussion lacks also a theory of the role of the public. With the help of arguments derived from pragmatism, one gets an action-based, socially constituted view of freedom in which the role of the public is essential. In general, it is argued that a socially constituted view of agency does not necessarily to lead to pessimistic conclusions about the freedom of action.

X-ray studies on crystalline complexes involving amino acids and peptides. XV. Crystal structures of L-lysine D-glutamate and L-lysine D-aspartate monohydrate and the effect of chirality on molecular aggregation

L-Lysine D-glutamate crystallizes in the monoclinic space group P2(1) with a = 4.902, b = 30.719, c = 9.679 A, beta = 90 degrees and Z = 4. The crystals of L-lysine D-aspartate monohydrate belong to the orthorhombic space group P2(1)2(1)2(1) with a = 5.458, b = 7.152, c = 36.022 A and Z = 4. The structures were solved by the direct methods and refined to R values of 0.125 and 0.040 respectively for 1412 and 1503 observed reflections. The glutamate complex is highly pseudosymmetric. The lysine molecules in it assume a conformation with the side chain staggered between the alpha-amino and the alpha-carboxylate groups. The interactions of the side chain amino groups of lysine in the two complexes are such that they form infinite sequences containing alternating amino and carboxylate groups. The molecular aggregation in the glutamate complex is very similar to that observed in L-arginine D-aspartate and L-arginine D-glutamate trihydrate, with the formation of double layers consisting of both types of molecules. In contrast to the situation in the other three LD complexes, the unlike molecules in L-lysine D-aspartate monohydrate aggregate into alternating layers as in the case of most LL complexes. The arrangement of molecules in the lysine layer is nearly the same as in L-lysine L-aspartate, with head-to-tail sequences as the central feature. The arrangement of aspartate ions in the layers containing them is, however, somewhat unusual. Thus the comparison between the LL and the LD complexes analyzed so far indicates that the reversal of chirality of one of the components in a complex leads to profound changes in molecular aggregation, but these changes could be of more than one type.

A numerical survey of relativistic rotating neutron star structures using the Hartle-Thorne formalism

A broad numerical survey of relativistic rotating neutron star structures was compiled using an exhaustive list of presently available equation of state models for neutron star matter. The structure parameters (spherical deformations in mass and radii, the moment of inertia and quadrupole moment, oblateness, and free precession) are calculated using the formalism proposed by Hartle and Thorne (1968). The results are discussed in relation to the relevant observational information. Binary pulsar data and X-ray burst sources provide information on the bulk properties of neutron stars, enabling the derivation of constraints that can be put on the structure of neutron stars and equation of state models.

Prediction of protein-protein interactions in dengue virus coat proteins guided by low resolution cryoEM structures

Background: Dengue virus along with the other members of the flaviviridae family has reemerged as deadly human pathogens. Understanding the mechanistic details of these infections can be highly rewarding in developing effective antivirals. During maturation of the virus inside the host cell, the coat proteins E and M undergo conformational changes, altering the morphology of the viral coat. However, due to low resolution nature of the available 3-D structures of viral assemblies, the atomic details of these changes are still elusive. Results: In the present analysis, starting from C alpha positions of low resolution cryo electron microscopic structures the residue level details of protein-protein interaction interfaces of dengue virus coat proteins have been predicted. By comparing the preexisting structures of virus in different phases of life cycle, the changes taking place in these predicted protein-protein interaction interfaces were followed as a function of maturation process of the virus. Besides changing the current notion about the presence of only homodimers in the mature viral coat, the present analysis indicated presence of a proline-rich motif at the protein-protein interaction interface of the coat protein. Investigating the conservation status of these seemingly functionally crucial residues across other members of flaviviridae family enabled dissecting common mechanisms used for infections by these viruses. Conclusions: Thus, using computational approach the present analysis has provided better insights into the preexisting low resolution structures of virus assemblies, the findings of which can be made use of in designing effective antivirals against these deadly human pathogens.

Hierarchy of structures in the family of amine templated open-framework gallium arsenates

Five new gallium arsenate compounds C2N2H10]Ga(H2AsO4)(HAsO4)(2)]center dot H2O, I; C2N2H10]Ga(OH)(AsO4)](2), II; C2N2H10]GaF(AsO4)](2), III; C3N2H12]Ga(OH)(AsO4)](2), IV; Ga2F3(AsO4)(HAsO4)]center dot 2H(3)O, V, have been synthesized under hydrothermal conditions and the structures determined employing single crystal X-ray diffraction studies. All the structures consist of octahedral gallium and tetrahedral arsenate units connected together forming a hierarchy of structures. Thus, one- (I), two- (II and IV) and three-dimensionally (III and V) extended structures have been observed. The Ga-O(H)/F-Ga connectivity in some of the structures suggests the coordination requirements posed by the octahedral gallium in these compounds. The observation of only one type of secondary building unit in the structures of III (SBU-4) and V (spiro-5) is unique and noteworthy. All the compounds have been characterized by a variety of techniques that include powder XRD, IR, and TGA. (C) 2010 Elsevier B. V. All rights reserved.

Synthesis, crystal structures and magnetic behavior of two 3D coordination polymers using N-(4/3-arboxyphenyl)iminodiacetic acids as bridging ligands

Research on structure and magnetic properties of polynuclear metal complexes to understand the structural and chemical factors governing the electronic exchange coupling mediated by multi-atom bridging ligands is of growing interest. Hydrothermal treatment of Ni(NO3)(2)center dot 6H(2)O with N-(4-carboxyphenyl)iminodiacetic acid N-4(H(3)CPIDA)] at 150 degrees C yielded a 3D coordination polymer of general formula Ni-3{N-4( CPIDA)}(2)(H2O)(3)]center dot 6H(2)O (1). An analogous network of general formula Co-3{N-3(CPIDA)}(2)(H2O)(3)]center dot 3H(2)O (2) was synthesized using N-(3-carboxyphenyl) iminodiacetic acid N-3(H(3)CPIDA)] in combination with Co(NO3)(2)center dot 6H(2)O under identical reaction condition. Both the complexes contain trinuclear secondary building unit, and crystallized in monoclinic system with space groups C2/c (1) and P2(1)/c (2), respectively. Variable temperature magnetic characterization of these complexes in the temperature range of 2-300 K indicated the presence of overall ferromagnetic and antiferromagnetic behavior for 1 and 2, respectively. Density functional theory calculations (B3LYP functional) were performed for further insight on the trinuclear units to provide a qualitative theoretical interpretation on the overall magnetic behavior of the complexes 1 and 2. (C) 2010 Elsevier B.V. All rights reserved.

Use of 2-pyrimidineamidoxime to generate polynuclear homo-/heterometallic assemblies: synthesis, crystal structures and magnetic study with theoretical investigations on the exchange mechanism

Three new transition metal complexes using 2-pyrimidineamidoxime (pmadH(2)) as multidentate chelating and/or bridging ligand have been synthesized and characterized. The ligand pmadH(2) has two potential bridging functional groups mu-O and mu-(N-O)] and consequently shows several coordination modes. While a polymeric 1D Cu-II complex Cu(pmadH(2))(2)(NO3)](NO3) (1) was obtained upon treatment of Cu(NO3)(2)center dot 3H(2)O with pmadH(2) at room temperature in the absence of base, a high temperature reaction in the presence of base yielded a tetranuclear Cu-II-complex Cu-4(pmad)(2)(pmadH)(2)(NO3)](NO3)(H2O) (2). One of the Cu-II centers is in a square pyramidal environment while the other three are in a square planar geometry. Reaction of the same ligand with an equimolar mixture of both Cu(NO3)(2)center dot 3H(2)O and NiCl2 center dot 6H(2)O yielded a tetranuclear heterometallic (Cu2Ni2II)-Ni-II complex Cu2Ni2(pmad)(2)(pmadH)(2)Cl-2]center dot H2O (3) containing both square planar (Ni-II) and square pyramidal (Cu-II) metal centers. Complexes 1-3 represent the first examples of polynuclear metal complexes of 2-pyrimidineamidoxime. The analysis of variable temperature magnetic susceptibility data of 2 reveals that both ferromagnetic and antiferromagnetic interactions exist in this complex (J(1) = +10.7 cm(-1) and J(2) = -2.7 cm(-1) with g = 2.1) leading to a resultant ferromagnetic behavior. Complex 3 shows expected antiferromagnetic interaction between two Cu-II centers through -N-O- bridging pathway with J(1) = -3.4 cm(-1) and g = 2.08. DFT calculations have been used to corroborate the magnetic results.