Effective use of ERTS multisensor data in the Northern Great Plains

The author has identified the following significant results. ERTS imagery was used as a tool in the identification and refinement of soil association areas; to classify land use patterns between crop and fallow fields; to identify corn, soybeans, and oats; and to identify broad generalized range ecosystems. Various data handling techniques were developed and applied to accomplish these tasks. A map outlining soil associations and relative land values was completed on a base mosaic of ERTS imagery and is included as an appendix to the report

Pupillometry, a bioengineering overview

The pupillary control system is examined using a microprocessor based integrative pupillometer. The real time software functions of the microprocessor include: data collection, stimulus generation and area to diameter conversion. Results of an analysis of linear and nonlinear phenomena are presented

Application of remote sensing technology in South Dakota to assess wildlife habitat change, describe meandering lakes, improve agricultural censusing, map Aspen, and quantify cell selection criteria for spatial data

There are no author-identified significant results in this report

Remote sensing applications to resource problems in South Dakota

There are no author-identified significant results in this report

The Birkhoff Theorem in Multidimensional Gravity

The validity conditions for the extended Birkhoff theorem in multidimensional gravity with $n$ internal spaces are formulated, with no restriction on space-time dimensionality and signature. Examples of matter sources and geometries for which the theorem is valid are given. Further generalization of the theorem is discussed.Comment: 8 page

Current Star Formation in the Ophiuchus and Perseus Molecular Clouds: Constraints and Comparisons from Unbiased Submillimeter and Mid-Infrared Surveys. II

We present a census of the population of deeply embedded young stellar objects (YSOs) in the Ophiuchus molecular cloud complex based on a combination of Spitzer Space Telescope mid-infrared data from the "Cores to Disks" (c2d) legacy team and JCMT/SCUBA submillimeter maps from the COMPLETE team. We have applied a method developed for identifying embedded protostars in Perseus to these datasets and in this way construct a relatively unbiased sample of 27 candidate embedded protostars with envelopes more massive than our sensitivity limit (about 0.1 M_sun). Embedded YSOs are found in 35% of the SCUBA cores - less than in Perseus (58%). On the other hand the mid-infrared sources in Ophiuchus have less red mid-infrared colors, possibly indicating that they are less embedded. We apply a nearest neighbor surface density algorithm to define the substructure in each of the clouds and calculate characteristic numbers for each subregion - including masses, star formation efficiencies, fraction of embedded sources etc. Generally the main clusters in Ophiuchus and Perseus (L1688, NGC1333 and IC348) are found to have higher star formation efficiencies than small groups such as B1, L1455 and L1448, which on the other hand are completely dominated by deeply embedded protostars. We discuss possible explanations for the differences between the regions in Perseus and Ophiuchus, such as different evolutionary timescales for the YSOs or differences, e.g., in the accretion in the two clouds.Comment: Accepted for publication in ApJ (56 pages, 13 figures; abstract abridged). Version with full-resolution figures available at http://www.astro.uni-bonn.de/~jes/paper120.pd

Mid- and high-J CO observations towards UCHIIs

A study of 12 ultracompact HII regions was conducted to probe the physical conditions and kinematics in the inner envelopes of the molecular clumps harboring them. The APEX telescope was used to observe the sources in the CO (4-3) and 13CO (8-7) lines. Line intensities were modeled with the RATRAN radiative transfer code using power laws for the density and temperature to describe the physical structure of the clumps. All sources were detected in both lines. The optically thick CO (4-3) line shows predominantly blue skewed profiles reminiscent of infall. Line intensities can be reproduced well using the physical structure of the clumps taken from the literature. The optically thick line profiles show that CO is a sensitive tracer of ongoing infall in the outer envelopes of clumps harboring ultracompact HII regions and hot molecular cores.Comment: APEX A&A special issue, accepte

Modes of Multiple Star Formation

This paper argues that star forming environments should be classified into finer divisions than the traditional isolated and clustered modes. Using the observed set of galactic open clusters and theoretical considerations regarding cluster formation, we estimate the fraction of star formation that takes place within clusters. We find that less than 10% of the stellar population originates from star forming regions destined to become open clusters, confirming earlier estimates. The smallest clusters included in the observational surveys (having at least N=100 members) roughly coincide with the smallest stellar systems that are expected to evolve as clusters in a dynamical sense. We show that stellar systems with too few members N < N_\star have dynamical relaxation times that are shorter than their formation times (1-2 Myr), where the critical number of stars N_\star \approx 100. Our results suggest that star formation can be characterized by (at least) three principal modes: I. isolated singles and binaries, II. groups (N<N_\star), and III. clusters (N>N_\star). Many -- if not most -- stars form through the intermediate mode in stellar groups with 10<N<100. Such groups evolve and disperse much more rapidly than open clusters; groups also have a low probability of containing massive stars and are unaffected by supernovae and intense ultraviolet radiation fields. Because of their short lifetimes and small stellar membership, groups have relatively little effect on the star formation process (on average) compared to larger open clusters.Comment: accepted to The Astrophysical Journa