Documentation for the spatial analysis system (SPAN) for resource use by animals

Nearest-neighbor analyses have been used with mapped data f or tests of spatial dispersion and association i n plant and animal ecology. This paper full describes a computer software package developed to use Monte Carlo trials instead of chi-squared distributions for assigning probabilities to observed values of nearest neighbor statistics. The program can factor-out the unique geometry of resources in a sample plot,which can affect locations of animals, thus testing for direct patterns among the animals independent of their resource patterns. The Kappa statistic for association is a1 o calculated a1though its application has met with limited success. A users manual and the Fortran program language is included. (80pp.

Advanced EHF Technologies for Lightweight Augmentation / Restoration Communications Satellites

Small EHF satellites can significantly complement the anti-jam service provided by basic EHF MILSATCOM space segments. Mobile/survivable launch vehicles with rapid launch preparations can be utilized to responsively deploy these small satellites into high altitude elliptical or circular orbits. From such orbits, only a few satellites are needed to provide high duty cycle coverage of a critical area. The communications capabilities provided by these EHF payloads can range from low data rate services (75 to 2400 bps per channel) to high data rate links (10 Mbps or more per link) depending on the payload configuration. Through the use of EHF waveform standards, these augmentation/ restoration satellites will be compatible with existing and planned EHF terminals. Advanced technologies permit the development of the highly capable lightweight payloads required for these roles. Some of the key payload technologies include adaptive uplink antennas; high speed low power digital signal processing subsystems; lightweight frequency hopping synthesizers; and efficient solid-state transmitters

Synthetic Approaches to the Anticancer Agent Streptonigrin

Pd-catalyzed coupling reactions have a central place in synthetic chemistry. In particular, studies from the DeShong laboratory have demonstrated that aryltrialkoxysilanes, in the presence of Pd(0) and fluoride, are capable of aryl group transfer to a range of aryl halides and triflates and allylic benzoates. The cross-coupling reaction represents an ideal opportunity to construct the tetracyclic core of the anticancer agent streptonigrin. This strategy is highly convergent and readily amenable to the synthesis of analogues, and as such would constitute an improvement over previous total syntheses of this natural product. A series of 4-bromopyridines (streptonigrin C ring precursors) were prepared, and their couplings with various arylsiloxanes (streptonigrin D ring precursors) examined. The coupling reaction generally tolerated the preparation of sterically demanding biaryls. The coupling of the 3-nitro-4-bromopyridine derivative was problematic, as dehalogenation was found to compete with arylation. The use of nitro group surrogates and a variety of catalyst systems offered no improvement. These results indicated the coupling reaction is highly sensitive to the electronic environment of bromopyridine. The analogous biaryl coupling reaction employing an organoboron species was more effective and allowed for additional streptonigrin CD analogues to be prepared. This reaction was found to be highly sensitive to the reaction conditions. A fully functionalized C ring precursor (prepared in 10 synthetic operations) underwent Suzuki coupling with a fully functionalized D ring precursor (prepared in 3 steps) to give an adduct possessing the streptonigrin CD skeleton. This species was elaborated to a precursor suitable for appendage to the AB ring component. A streptonigrin A ring derivative has been prepared in 6 steps from resorcinol. The functionalities present in this species are compatible with several possible strategies to prepare the ABCD framework of the natural product. Results of a model study indicate that the coupling of an A ring aryl siloxane with the CD fragment (possessing a three-carbon fragment in the form of an allylic benzoate) is viable approach to the natural product. Further studies are warranted to evaluate the requisite annulation to prepare the B ring

Electrochemical Cell with Improved Water or Gas Management

An electrochemical cell having a water/gas porous separator prepared from a polymeric material and one or more conductive cell components that pass through, or are located in close proximity to, the water/gas porous separator, is provided. The inventive cell provides a high level of in-cell electrical conductivity

Spitzer Warm Mission Transition and Operations

Following the successful dynamic planning and implementation of IRAC Warm Instrument Characterization activities, transition to Spitzer Warm Mission operations has gone smoothly. Operation teams procedures and processes required minimal adaptation and the overall composition of the Mission Operation System retained the same functionality it had during the Cryogenic Mission. While the warm mission scheduling has been simplified because all observations are now being made with a single instrument, several other differences have increased the complexity. The bulk of the observations executed to date have been from ten large Exploration Science programs that, combined, have more complex constraints, more observing requests, and more exo-planet observations with durations of up to 145 hours. Communication with the observatory is also becoming more challenging as the Spitzer DSN antenna allocations have been reduced from two tracking passes per day to a single pass impacting both uplink and downlink activities. While IRAC is now operating with only two channels, the data collection rate is roughly 60% of the four-channel rate leaving a somewhat higher average volume collected between the less frequent passes. Also, the maximum downlink data rate is decreasing as the distance to Spitzer increases requiring longer passes. Nevertheless, with well over 90% of the time spent on science observations, efficiency has equaled or exceeded that achieved during the cryogenic mission