Assessment of practicality of remote sensing techniques for a study of the effects of strip mining in Alabama

Because of the volume of coal produced by strip mining, the proximity of mining operations, and the diversity of mining methods (e.g. contour stripping, area stripping, multiple seam stripping, and augering, as well as underground mining), the Warrior Coal Basin seemed best suited for initial studies on the physical impact of strip mining in Alabama. Two test sites, (Cordova and Searles) representative of the various strip mining techniques and environmental problems, were chosen for intensive studies of the correlation between remote sensing and ground truth data. Efforts were eventually concentrated in the Searles Area, since it is more accessible and offers a better opportunity for study of erosional and depositional processes than the Cordova Area

Enabling Conditions for Organizational Learning: A Study in International Business Ventures

The significance of international business in the world economy has greatly increased since the beginning of the 1980s, mainly as a consequence of the expansion in the flow of foreign direct investment. Declining costs of transportation and advances in information technology have allowed transnational corporations to spread the production of goods and services around the world. Increasing competition has represented a continuous pressure on organizations for faster or better adaptation to a changing environment. Despite these pressures for change, organizations also need some stability in order to make sense of both the direction they want to take, and the actions which can help them to keep the course. Knowledge about an organization's internal affairs and its interaction with the external environment has become a main source of competitive advantage. The process by which organizations create or acquire this knowledge has been called organizational learning. This dissertation seeks to identify and discuss some key factors which facilitate the occurrence of organizational learning in International Business Ventures (IBVs), here understood as the involvement of foreign investing companies in host countries, with some degree of management that is shared between nationals of both local and foreign countries. The dissertation describes four in-depth case studies in two IBVs, one located in the UK and the other in Brazil. The first company is a subsidiary of Toshiba, which produces television and air conditioner sets for the European market. The second company is a joint venture between Toshiba and Semp, a local company, which produces television sets, VCRs and audio equipment for the Brazilian market. Due to the lack of empirical research in the field of this study, data collection and analysis followed the broad lines of the grounded theory approach. Two processes of organizational learning occurring during the last few years in each company were identified and reconstructed through semi-structured interviews with their key participants. Data about the companies and the processes was supplemented with the use of secondary sources. Througout the whole study particular attention was directed to the context where the processes developed. All interviews were tape recorded and transcribed verbatim. The data were then qualitatively coded in order to help the identification of the main themes and categories related to the objective of the study. Literature was reviewed during all stages of the research in order both to stimulate theoretical sensitivity and to enhance the generalizability into theory of the main findings of the study. Some of the main areas of contribution from the research include: the relationship between time and behavioural/cognitive changes in processes of organizational learning; the relationship between time and acquisition of tacit/explicit knowledge; the analysis of outcomes as moments in a process, and their use as leverage for continuous learning; the importance of control for guiding the process and evaluating its outcomes; communication as a major difficulty in the work of cross-cultural teams, and strategies to overcome such difficulties; and the relationship between local and foreign knowledge for the management of IBVs. In addition, the analysis of processes of organizational learning and the attention given to their context represent a methodological contribution of the study

Kappa-symmetric Derivative Corrections to D-brane Dynamics

We show how the superembedding formalism can be applied to construct manifestly kappa-symmetric higher derivative corrections for the D9-brane. We also show that all correction terms appear at even powers of the fundamental length scale $l$. We explicitly construct the first potential correction, which corresponds to the kappa-symmetric version of the $\partial^4 F^4$, which one finds from the four-point amplitude of the open superstring.Comment: 20 pages. Minor changes, added reference

The cohomology of superspace, pure spinors and invariant integrals

The superform construction of supersymmetric invariants, which consists of integrating the top component of a closed superform over spacetime, is reviewed. The cohomological methods necessary for the analysis of closed superforms are discussed and some further theoretical developments presented. The method is applied to higher-order corrections in heterotic string theory up to \a'^3. Some partial results on $N=2,d=10$ and $N=1,d=11$ are also given.Comment: 24 pages. Minor changes; added reference

Light-like polygonal Wilson loops in 3d Chern-Simons and ABJM theory

We study light-like polygonal Wilson loops in three-dimensional Chern-Simons and ABJM theory to two-loop order. For both theories we demonstrate that the one-loop contribution to these correlators cancels. For pure Chern-Simons, we find that specific UV divergences arise from diagrams involving two cusps, implying the loss of finiteness and topological invariance at two-loop order. Studying those UV divergences we derive anomalous conformal Ward identities for n-cusped Wilson loops which restrict the finite part of the latter to conformally invariant functions. We also compute the four-cusp Wilson loop in ABJM theory to two-loop order and find that the result is remarkably similar to that of the corresponding Wilson loop in N=4 SYM. Finally, we speculate about the existence of a Wilson loop/scattering amplitude relation in ABJM theory.Comment: 37 pages, many figures; v2: references added, minor changes; v3: references added, sign error fixed and note adde

All-electron quantum Monte Carlo calculations for the noble gas atoms He to Xe

We report all-electron variational and diffusion quantum Monte Carlo (VMC and DMC) calculations for the noble gas atoms He, Ne, Ar, Kr, and Xe. The calculations were performed using Slater-Jastrow wave functions with Hartree-Fock single-particle orbitals. The quality of both the optimized Jastrow factors and the nodal surfaces of the wave functions declines with increasing atomic number Z, but the DMC calculations are tractable and well behaved in all cases. We discuss the scaling of the computational cost of DMC calculations with Z

Spatially-resolved electronic and vibronic properties of single diamondoid molecules

Diamondoids are a unique form of carbon nanostructure best described as hydrogen-terminated diamond molecules. Their diamond-cage structures and tetrahedral sp3 hybrid bonding create new possibilities for tuning electronic band gaps, optical properties, thermal transport, and mechanical strength at the nanoscale. The recently-discovered higher diamondoids (each containing more than three diamond cells) have thus generated much excitement in regards to their potential versatility as nanoscale devices. Despite this excitement, however, very little is known about the properties of isolated diamondoids on metal surfaces, a very relevant system for molecular electronics. Here we report the first molecular scale study of individual tetramantane diamondoids on Au(111) using scanning tunneling microscopy and spectroscopy. We find that both the diamondoid electronic structure and electron-vibrational coupling exhibit unique spatial distributions characterized by pronounced line nodes across the molecular surfaces. Ab-initio pseudopotential density functional calculations reveal that the observed dominant electronic and vibronic properties of diamondoids are determined by surface hydrogen terminations, a feature having important implications for designing diamondoid-based molecular devices.Comment: 16 pages, 4 figures. to appear in Nature Material