Effect of environment on biological burden during spacecraft assembly

Determining effects of environment on accumulation of biological burden on spacecraft during assembl

Data assimilation insights on selecting the most valuable atmospheric measurements

We discuss how objective guidance on selecting the most valuable atmospheric measurements on future Mars spacecraft missions can be provided through already developed Martian atmospheric data assimilation systems, and in particular through Observing System Simulation Experiments (OSSEs) which are widely used to design instruments for the Earth’s atmosphere

Report of the direct infrared sensors panel

The direct infrared sensors panel considered a wide range of options for technologies relevant to the science goals of the Astrotech 21 mission set. Among the technologies assessed are: large format arrays; photon counting detectors; higher temperature 1 to 10 micro-m arrays; impurity band conduction (IBC) or blocked impurity band (BIB) detectors; readout electronics; and adapting the Space Infrared Telescope Facility and Hubble Space Telescope. Detailed development plans were presented for each of these technology areas

Charge Modulations in the Superconducting State of the Cuprates

Motivated by the recent scanning tunneling microscopy (STM) and neutron scattering experiments, we investigate various charge density wave orders coexisting with superconductivity in the cuprate superconductors. The explicit expressions of the local density of states and its Fourier component at the ordering wavevector for the weak charge modulations are derived. It is shown that the STM experiments in $Bi_2Sr_2CaCu_2O_{8+\delta}$ cannot be explained by a site- or bond-centered charge modulation alone, but agree well with the presence of the dimerization hopping and transverse pairing modulations. We also calculate the spectral function for the charged stripes, which is measured by the ARPES experiments.Comment: 3 pages with 4 figures. To be published in PR

Discrete phase space based on finite fields

The original Wigner function provides a way of representing in phase space the quantum states of systems with continuous degrees of freedom. Wigner functions have also been developed for discrete quantum systems, one popular version being defined on a 2N x 2N discrete phase space for a system with N orthogonal states. Here we investigate an alternative class of discrete Wigner functions, in which the field of real numbers that labels the axes of continuous phase space is replaced by a finite field having N elements. There exists such a field if and only if N is a power of a prime; so our formulation can be applied directly only to systems for which the state-space dimension takes such a value. Though this condition may seem limiting, we note that any quantum computer based on qubits meets the condition and can thus be accommodated within our scheme. The geometry of our N x N phase space also leads naturally to a method of constructing a complete set of N+1 mutually unbiased bases for the state space.Comment: 60 pages; minor corrections and additional references in v2 and v3; improved historical introduction in v4; references to quantum error correction in v5; v6 corrects the value quoted for the number of similarity classes for N=

Weak Charge-Changing Flow in Expanding r-Process Environments

We assess the prospects for attaining steady nuclear flow equilibrium in expanding r-process environments where beta decay and/or neutrino capture determine the nuclear charge-changing rates. For very rapid expansions, we find that weak steady flow equilibrium normally cannot be attained. However, even when neutron capture processes freeze out in such nonequilibrium conditions, abundance ratios of nuclear species in the r-process peaks might still mimic those attained in weak steady flow. This result suggests that the r-process yield in a regime of rapid expansion can be calculated reliably only when all neutron capture, photodisintegration, and weak interaction processes are fully coupled in a dynamical calculation. We discuss the implications of these results for models of the r-process sited in rapidly expanding neutrino-heated ejecta.Comment: 21 pages, AAS LaTex, 2 postscript figure

Status of Outer Planet Global Reference Atmospheric Model (GRAM) Upgrades

The inability to test planetary spacecraft in the flight environment prior to a mission requires engineers to rely on ground-based testing and models of the vehicle and expected environments. One of the most widely used engineering models of the atmosphere is the Global Reference Atmospheric Model (GRAM) developed and maintained by the NASA Marshall Space Flight Center (MSFC). The NASA Science Mission Directorate (SMD) has provided funding support to upgrade the GRAMs

Variability Flagging in the Wide-field Infrared Survey Explorer Preliminary Data Release

The Wide-field Infrared Survey Explorer Preliminary Data Release Source Catalog contains over 257 million objects. We describe the method used to flag variable source candidates in the Catalog. Using a method based on the chi-square of single-exposure flux measurements, we generated a variability flag for each object, and have identified almost 460,000 candidate sources that exhibit significant flux variability with greater than ~7σ confidence. We discuss the flagging method in detail and describe its benefits and limitations. We also present results from the flagging method, including example light curves of several types of variable sources including Algol-type eclipsing binaries, RR Lyr, W UMa, and a blazar candidate

Sea Level Rise and Storm Surge Projections for the National Park Service

Over one quarter of the units of the National Park System occur along ocean coastlines. Ongoing changes in relative sea levels and the potential for increasing storm surges due to anthropogenic climate change and other factors present challenges to national park managers. This report summarizes work done by the University of Colorado in partnership with the National Park Service (NPS) to provide sea level rise and storm surge projections to coastal area national parks using information from the United Nations Intergovernmental Panel on Climate Change (IPCC) and storm surge scenarios from National Oceanic and Atmospheric Administration (NOAA) models. This research is the first to analyze IPCC and NOAA projections of sea level and storm surge under climate change for U.S. national parks. Results illustrate potential future inundation and storm surge under four greenhouse gas emissions scenarios. In addition to including multiple scenarios, the analysis considers multiple time horizons (2030, 2050 and 2100). This analysis provides sea level rise projections for 118 park units and storm surge projections for 79 of those parks. Within the National Park Service, the National Capital Region is projected to experience the highest average rate of sea level change by 2100. The coastline adjacent to the Outer Banks Group of parks in the Southeast Region is projected to experience the highest sea level rise by 2100. The Southeast Region is projected to experience the highest storm surges based on historical data and NOAA storm surge models. These results are intended to inform park planning and adaptation strategies for resources managed by the National Park Service. Sea level change and storm surge pose considerable risks to infrastructure, archeological sites, lighthouses, forts, and other historic structures in coastal units of the national park system. Understanding projections for continued change can better guide protection of such resources for the benefit of long-term visitor enjoyment and safety

Integration of Pasturing Systems for Cattle Finishing Programs—A Progress Report

This progress report is an introduction to a study to evaluate the incorporation of rotational pasturing systems into cattle finishing programs. Because the first year is still in progress and the first trial is not complete, few data are available. However, there is a suggestion that feeding an ionophore to young calves on pasture may result in improved daily gains