A laboratory experiment in calculus for the high school

Thesis (M.A.)--Boston Universit

Intelligence/Electronic Warfare (IEW) direction-finding and fix estimation analysis report. Volume 2: Trailblazer

An analysis of the direction finding (DF) and fix estimation algorithms in TRAILBLAZER is presented. The TRAILBLAZER software analyzed is old and not currently used in the field. However, the algorithms analyzed are used in other current IEW systems. The underlying algorithm assumptions (including unmodeled errors) are examined along with their appropriateness for TRAILBLAZER. Coding and documentation problems are then discussed. A detailed error budget is presented

Theoretical and Experimental Investigation of High-Latitude Outflow for Ions and Neutrals

The outflow of ions at high latitudes is one mechanism thought to populate the magnetosphere with ionospheric ions [H+, He+, O+]. Computer modeling can give an insight into the mechanisms and rates at which these ions can populate the magnetosphere, but for atomic oxygen the temperature is about 40% lower than measurement. This can be accounted for by the inclusion of a hot O population at a higher temperature, of about 4000K

Measurements of the Diffuse Ultraviolet Background and the Terrestrial Airglow with the Space Telescope Imaging Spectrograph

Far-UV observations in and near the Hubble Deep Fields demonstrate that the Space Telescope Imaging Spectrograph (STIS) can potentially obtain unique and precise measurements of the diffuse far-ultraviolet background. Although STIS is not the ideal instrument for such measurements, high-resolution images allow Galactic and extragalactic objects to be masked to very faint magnitudes, thus ensuring a measurement of the truly diffuse UV signal. The programs we have analyzed were not designed for this scientific purpose, but would be sufficient to obtain a very sensitive measurement if it were not for a weak but larger-than-expected signal from airglow in the STIS 1450-1900 A bandpass. Our analysis shows that STIS far-UV crystal quartz observations taken near the limb during orbital day can detect a faint airglow signal, most likely from NI\1493, that is comparable to the dark rate and inseparable from the far-UV background. Discarding all but the night data from these datasets gives a diffuse far-ultraviolet background measurement of 501 +/- 103 ph/cm2/sec/ster/A, along a line of sight with very low Galactic neutral hydrogen column (N_HI = 1.5E20 cm-2) and extinction (E(B-V)=0.01 mag). This result is in good agreement with earlier measurements of the far-UV background, and should not include any significant contribution from airglow. We present our findings as a warning to other groups who may use the STIS far-UV camera to observe faint extended targets, and to demonstrate how this measurement may be properly obtained with STIS.Comment: 7 pages, Latex. 4 figures. Uses corrected version of emulateapj.sty and apjfonts.sty (included). Accepted for publication in A

Uncertainty Associated with Modeling the Global Ionosphere

A study has been conducted of the effect that different physical assumptions have on global models of the electron density distribution. The study was conducted with the Ionosphere Forecast Model (IFM) and the Ionosphere Plasmasphere Model (IPM) developed by Utah State University. Both physics-based, time-dependent, global models use the same empirical models for the neutral atmosphere (MSIS) and neutral wind (Horizontal Wind Model, HWM), but the altitude range, thermal structure, number of ion species, and magnetic 2ield are different. The IFM covers the altitude range from 90-1400 km, calculates the densities for four ions (NO+, O2+, N2+, O+), has a simple prescription for calculating H+, and is based on a tilted offset dipole magnetic 2ield. The IPM extends from 90-20,000 km, includes six ion species (NO+, O2+, N2+, O+, H+, He+), is based on the International Geomagnetic Reference Field (IGRF), and allows for inter-hemisphere 2low. Therefore, the comparison of these models will elucidate the quantitative effect of these differences. In addition, simulations were conducted to study the effect of uncertainties in the zonal wind, secondary electron production, O+/ O collision frequency, tidal structure, and state of plasmasphere re2illing. The simulations were conducted for a wide range of solar, seasonal, and geomagnetic activity levels. Quantitative results will be given that establish the importance of the various physical processes

The Neuroscience Information Framework: A Data and Knowledge Environment for Neuroscience

With support from the Institutes and Centers forming the NIH Blueprint for Neuroscience Research, we have designed and implemented a new initiative for integrating access to and use of Web-based neuroscience resources: the Neuroscience Information Framework. The Framework arises from the expressed need of the neuroscience community for neuroinformatic tools and resources to aid scientific inquiry, builds upon prior development of neuroinformatics by the Human Brain Project and others, and directly derives from the Society for Neuroscience’s Neuroscience Database Gateway. Partnered with the Society, its Neuroinformatics Committee, and volunteer consultant-collaborators, our multi-site consortium has developed: (1) a comprehensive, dynamic, inventory of Web-accessible neuroscience resources, (2) an extended and integrated terminology describing resources and contents, and (3) a framework accepting and aiding concept-based queries. Evolving instantiations of the Framework may be viewed at http://nif.nih.gov, http://neurogateway.org, and other sites as they come on line

Modeling the Midlatitude Ionosphere Storm-Enhanced Density Distribution With a Data Assimilation Model

The Utah State University Global Assimilation of Ionospheric Measurements‐Gauss Markov model has been used to investigate the distribution of ionospheric plasma during storm times over the continental United States. Storm periods dramatically increase the effects of space weather on the ionosphere and upper atmosphere, leading to impacts on over‐the‐horizon radars, Global Positioning System location determination, spacecraft charging, power grid overloads, and disruption of the Federal Aviation Administration Wide Area Augmentation System to name a few. Four storm periods were investigated where strong storm‐enhanced densities (SEDs) were present: two strong, October 2003 and November 2003, and two moderate, August 2010 and August 2011. It was found that a fundamental difference in the SED formation exists between the strong and moderate storms. For the strong storms, the SED was formed from the plasma in the northern equatorial anomaly crest, with the plasma in the SED channel lifting the closer it came to the high latitudes. For the moderate storms, the SED appeared to be unconnected to the northern anomaly crest but was rather produced locally in the SED channel, along with no corresponding increase in layer height associated with the SED evident in the mode

Molecules in G1.6-0.025 - 'Hot' Chemistry in the Absence of Star Formation at the Periphery of the Galactic Center Region

We present molecular line mapping of the Giant Molecular Cloud G1.6-0.025, which is located at the high longitude end of the Central Molecular Zone of our Galaxy. We assess the degree of star formation activity in that region using several tracers and find very little. We made a large scale, medium (2') resolution map in the J = 2-1 transition of SiO for which we find clumpy emission over a ~0.8 x 0.3 degree-sized region stretching along the Galactic plane. Toward selected positions we also took spectra in the easy to excite J_k=2_k-1_k quartet of CH3OH and the CS 2-1 line. Throughout the cloud these \meth lines are, remarkably, several times stronger than, both, the CS and the SiO lines. The large widths of all the observed lines, similar to values generally found in the Galactic center, indicate a high degree of turbulence. Several high LSR velocity clumps that have 0-80 km/s higher velocities than the bulk of the molecular cloud appear at the same projected position as "normal" velocity material; this may indicate cloud-cloud collisions. Statistical equilibrium modeling of the CH3OH lines observed by us and others yield relatively high densities and moderate temperatures for a representative dual velocity position. We find 8 10^4 cm-3/30 K for material in the G1.6-0.025 cloud and a higher temperature (190 K), but a 50% lower density in a high velocity clump projected on the same location. Several scenarios are discussed in which shock chemistry might enhance the CH3OH and SiO abundances in G1.6-0.025 and elsewhere in the Central Molecular Zone.Comment: 51 pages incl. 9 figures and 6 Tables, ApJ (in press

A new classification and linear sequence of extant gymnosperms

A new classification and linear sequence of the gymnosperms based on previous molecular and morphological phylogenetic and other studies is presented. Currently accepted genera are listed for each family and arranged according to their (probable) phylogenetic position. A full synonymy is provided, and types are listed for accepted genera. An index to genera assists in easy access to synonymy and family placement of genera.Peer reviewe