Verification of the Kcat Value of AAT via COPASI

PLP is a chromophoric cofactor required for catalytic activity by a wide variety of enzymes. While PLP enzymes are thermally activated in vivo, it has been reported that some PLP enzymes can be activated by UV light. One enzyme that uses PLP as a cofactor is apsartate aminotransferase (AAT). Previous studies with AAT suggest that the carbanionic quinonoid intermediate is photogenerated by UV laser excitation. AAT is central to nitrogen metabolism in all living systems and has a large body of literature. As such, it is a useful prototype for the fundamental studies on this class of enzymes which were previously conducted. In order to verify these experimental results, the computer program COPASI was used. Two models of AAT mechanisms were examined using COPASI one with the quinonoid intermediate on the productive path and one with the quinonoid off the productive path

Remotely sensing the morphometrics and dynamics of a cold region dune field using historical aerial photography and airborne LIDAR data

© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Remote Sensing 10 (2018): 792, doi:10.3390/rs10050792.This study uses an airborne Light Detection and Ranging (LiDAR) survey, historical aerial photography and historical climate data to describe the character and dynamics of the Nogahabara Sand Dunes, a sub-Arctic dune field in interior Alaska’s discontinuous permafrost zone. The Nogahabara Sand Dunes consist of a 43-km2 area of active transverse and barchanoid dunes within a 3200-km2 area of vegetated dune and sand sheet deposits. The average dune height in the active portion of the dune field is 5.8 m, with a maximum dune height of 28 m. Dune spacing is variable with average crest-to-crest distances for select transects ranging from 66–132 m. Between 1952 and 2015, dunes migrated at an average rate of 0.52 m a−1. Dune movement was greatest between 1952 and 1978 (0.68 m a−1) and least between 1978 and 2015 (0.43 m a−1). Dunes migrated predominantly to the southeast; however, along the dune field margin, net migration was towards the edge of the dune field regardless of heading. Better constraining the processes controlling dune field dynamics at the Nogahabara dunes would provide information that can be used to model possible reactivation of more northerly dune fields and sand sheets in response to climate change, shifting fire regimes and permafrost thaw.Funding for this research was provided by the U.S. Geological Survey Land Change Science and Land Remote Sensing programs, the U.S. Fish andWildlife Service and the University of Alaska Fairbanks

A Blue Tilt in the Globular Cluster System of the Milky Way-like Galaxy NGC 5170

Here we present HST/ACS imaging, in the B and I bands, of the edge-on Sb/Sc galaxy NGC 5170. Excluding the central disk region region, we detect a 142 objects with colours and sizes typical of globular clusters (GCs). Our main result is the discovery of a `blue tilt' (a mass-metallicity relation), at the 3sigma level, in the metal-poor GC subpopulation of this Milky Way like galaxy. The tilt is consistent with that seen in massive elliptical galaxies and with the self enrichment model of Bailin & Harris. For a linear mass-metallicity relation, the tilt has the form Z ~ L^{0.42 +/- 0.13}. We derive a total GC system population of 600 +/- 100, making it much richer than the Milky Way. However when this number is normalised by the host galaxy luminosity or stellar mass it is similar to that of M31. Finally, we report the presence of a potential Ultra Compact Dwarf of size ~ 6 pc and luminosity M_I ~ -12.5, assuming it is physically associated with NGC 5170.Comment: Accepted for publication in MNRAS, 11 pages, 10 figure

An Analysis of Delistings from the United Nations Global Compact

This study analyzes which firms leave multi-stakeholder initiatives (MSIs) for corporate social responsibility. Based on an analysis of all active and delisted participants from the UN Global Compact between 2000 and 2015 (n= 15,853), we find that SMEs are more likely to be delisted than larger and publicly-listed firms; that early adopters face a higher risk of being delisted; and that the presence of a local network in a country reduces the likelihood of being delisted. We theorize that MSIs face a participant self-selection bias over time and that local networks enable legitimacy spillover effects that prevent firms from exiting

A Resource Dependence Perspective on Delistings from the United Nations Global Compact

This study analyzes which firms leave multi-stakeholder initiatives (MSIs) for corporate social responsibility (CSR). Based on an analysis of all active and delisted participants from the UN Global Compact between 2000 and 2015 (n= 15,853), we find that SMEs are more likely to be delisted than larger and publicly-traded firms; that early adopters face a higher risk of being delisted; and that the presence of a local network in a country reduces the likelihood of being delisted. Based on this, we extend resource dependence theory in the context of CSR by theorizing (a) the effect of participant heterogeneity on resource dependence relationships and (b) the role of indirect influence pathways where stakeholders work through allies to manipulate the flow of resources to a firm

Efficient intra- and inter-night linking of asteroid detections using kd-trees

The Panoramic Survey Telescope And Rapid Response System (Pan-STARRS) under development at the University of Hawaii's Institute for Astronomy is creating the first fully automated end-to-end Moving Object Processing System (MOPS) in the world. It will be capable of identifying detections of moving objects in our solar system and linking those detections within and between nights, attributing those detections to known objects, calculating initial and differentially-corrected orbits for linked detections, precovering detections when they exist, and orbit identification. Here we describe new kd-tree and variable-tree algorithms that allow fast, efficient, scalable linking of intra and inter-night detections. Using a pseudo-realistic simulation of the Pan-STARRS survey strategy incorporating weather, astrometric accuracy and false detections we have achieved nearly 100% efficiency and accuracy for intra-night linking and nearly 100% efficiency for inter-night linking within a lunation. At realistic sky-plane densities for both real and false detections the intra-night linking of detections into `tracks' currently has an accuracy of 0.3%. Successful tests of the MOPS on real source detections from the Spacewatch asteroid survey indicate that the MOPS is capable of identifying asteroids in real data.Comment: Accepted to Icaru

Alpha-Vacua, Black Holes, and AdS/CFT

The Schwarzschild, Schwarzschild-AdS, and Schwarzschild-de Sitter solutions all admit freely acting discrete involutions which commute with the continuous symmetries of the spacetimes. Intuitively, these involutions correspond to the antipodal map of the corresponding spacetimes. In analogy with the ordinary de Sitter example, this allows us to construct new vacua by performing a Mottola-Allen transform on the modes associated with the Hartle-Hawking, or Euclidean, vacuum. These vacua are the `alpha'-vacua for these black holes. The causal structure of a typical black hole may ameliorate certain difficulties which are encountered in the case of de Sitter alpha-vacua. For Schwarzschild-AdS black holes, a Bogoliubov transformation which mixes operators of the two boundary CFT's provides a construction of the dual CFT alpha-states. Finally, we analyze the thermal properties of these vacua.Comment: 40 pages REVTeX and AMSLaTeX, 17 black&white eps figures. v3: references added. v4: details of the pinch singularity avoidance for the string quantization of the Rindler space toy model have been added in both the body of the paper and in a new 7 page appendix. Other clarifications and references added. This is the version accepted for publication in Class. Quant. Gra