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NASA Science Mission Directorate's In-Space Propulsion Technology Program is sponsoring the development of a 3.5 kW-class engineering development unit Hall thruster for implementation in NASA science and exploration missions. NASA Glenn and Aerojet are developing a high fidelity high voltage Hall accelerator that can achieve specific impulse magnitudes greater than 2,700 seconds and xenon throughput capability in excess of 300 kilograms. Performance, plume mappings, thermal characterization, and vibration tests of the high voltage Hall accelerator engineering development unit have been performed. Performance test results indicated that at 3.9 kW the thruster achieved a total thrust efficiency and specific impulse of 58%, and 2,700 sec, respectively. Thermal characterization tests indicated that the thruster component temperatures were within the prescribed material maximum operating temperature limits during full power thruster operation. Finally, thruster vibration tests indicated that the thruster survived the 3-axes qualification full-level random vibration test series. Pre and post-vibration test performance mappings indicated almost identical thruster performance. Finally, an update on the development progress of a power processing unit and a xenon feed system is provided.

We have developed an efficient method for the simultaneous introduction of up to three mutations in a plasmid DNA via homologous recombination. The strategy is compatible with a variety of mutations, including degenerate codons in plasmids of different sizes. In contrast to other methodologies, this approach employs the same set of reagents for both single- and multi-site mutagenesis assays, minimizes the required protocol steps, and exhibits remarkably high mutagenesis efficiencies.

The In-Space Propulsion Technology (ISPT) program was tasked in 2009 to start development of propulsion technologies that would enable future sample return missions. ISPT's sample return technology development areas are diverse. Sample Return Propulsion (SRP) addresses electric propulsion for sample return and low cost Discovery-class missions, propulsion systems for Earth Return Vehicles (ERV) including transfer stages to the destination, and low technology readiness level (TRL) advanced propulsion technologies. The SRP effort continues work on HIVHAC thruster development to transition into developing a Hall-effect propulsion system for sample return (ERV and transfer stages) and low-cost missions. Previous work on the lightweight propellant-tanks continues for sample return with direct applicability to a Mars Sample Return (MSR) mission with general applicability to all future planetary spacecraft. The Earth Entry Vehicle (EEV) work focuses on building a fundamental base of multi-mission technologies for Earth Entry Vehicles (MMEEV). The main focus of the Planetary Ascent Vehicles (PAV) area is technology development for the Mars Ascent Vehicle (MAV), which builds upon and leverages the past MAV analysis and technology developments from the Mars Technology Program (MTP) and previous MSR studies.

Since 2001, the In-Space Propulsion Technology (ISPT) program has been developing and delivering in-space propulsion technologies that will enable or enhance NASA robotic science missions. These in-space propulsion technologies are applicable, and potentially enabling, for future NASA flagship and sample return missions currently being considered. They have a broad applicability to future competed mission solicitations. The high-temperature Advanced Material Bipropellant Rocket (AMBR) engine, providing higher performance for lower cost, was completed in 2009. Two other ISPT technologies are nearing completion of their technology development phase: 1) NASA's Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6–7 kW throttle-able gridded ion system; and 2) Aerocapture technology development with investments in a family of thermal protection system (TPS) materials and structures; guidance, navigation, and control (GNC aerothermal effect models; and atmospheric models for Earth, Titan, Mars and Venus. This paper provides status of the technology development, applicability, and availability of in-space propulsion technologies that have recently completed their technology development and will be ready for infusion into NASA's Discovery, New Frontiers, SMD Flagship, or technology demonstration missions.

Summary Fluorescent proteins (FPs) have become essential tools for a growing number of fields in biology. However, such tools have not been widely adopted for use in microalgal research. The aim of this study was to express and compare six FPs (blue mTagBFP, cyan mCerulean, green CrGFP, yellow Venus, orange tdTomato and red mCherry) in the popular model microalga Chlamydomonas reinhardtii. To circumvent the transgene silencing that often occurs in C. reinhardtii, the FPs were expressed from the nuclear genome as transcriptional fusions with the sh-ble antibiotic resistance gene, with the foot and mouth disease virus 2A self-cleaving sequence placed between the coding sequences. All ble–2A–FPs tested are well-expressed and efficiently processed to yield mature, unfused FPs that localize throughout the cytoplasm. The fluorescence signals of each FP were detectable in whole cells by fluorescence microplate reader analysis, live-cell fluorescence microscopy, and flow cytometry. Furthermore, we report a comparative analysis of fluorescence levels relative to auto-fluorescence for the chosen FPs. Finally, we demonstrate that the ble–2A expression vector may be used to fluorescently label an endogenous protein (α-tubulin). We show that the mCerulean–α-tubulin fusion protein localizes to the cytoskeleton and flagella, as expected, and that cells containing this fusion protein had normal cellular function. Overall, our results indicate that, by use of the ble–2A nuclear expression construct, a wide array of FP tools and technologies may be applied to microalgal research, opening up many possibilities for microalgal biology and biotechnology.

In recent years there has been a growing interest in the precise and concerted assembly of multiple DNA fragments of diverse sizes, including chromosomes, and the fine tuning of gene expression levels and protein activity. Commercial DNA assembly solutions have not been conceived to support the cloning of very large or very small genetic elements or a combination of both. Here we summarize a series of protocols that allow the seamless, simultaneous, flexible, and highly efficient assembly of DNA elements of a wide range of sizes (up to hundred thousand base pairs). The protocols harness the power of homologous recombination and are performed either in vitro or within the living cells. The DNA fragments may or may not share homology at their ends. An efficient site-directed mutagenesis protocol enhanced by homologous recombination is also described.

In recent years there has been a growing interest in the precise and concerted assembly of multiple DNA fragments of diverse sizes, including chromosomes, and the fine tuning of gene expression levels and protein activity. Commercial DNA assembly solutions have not been conceived to support the cloning of very large or very small genetic elements or a combination of both. Here we summarize a series of protocols that allow the seamless, simultaneous, flexible, and highly efficient assembly of DNA elements of a wide range of sizes (up to hundred thousand base pairs). The protocols harness the power of homologous recombination and are performed either in vitro or within the living cells. The DNA fragments may or may not share homology at their ends. An efficient site-directed mutagenesis protocol enhanced by homologous recombination is also described.

NASA’s Science Mission Directorate In-Space Propulsion Technology Program is funding NASA Glenn Research Center (GRC) to develop a high specific impulse, long-life, low-cost high voltage Hall accelerator (HiVHAc) engineering model (EM) Hall effect thruster. NASA GRC and Aerojet have completed the fabrication and extensive testing of a HiVHAc EM thruster that incorporates a discharge channel replacement mechanism as a means of achieving long-life. HiVHAc EM performance characterization indicated that the design met and exceeded desired performance levels. A new throttle table that includes high thrust-to-power operation has improved the thruster’s performance for some NASA science missions. However, testing also revealed that thermal, magnetic circuit saturation, and channel replacement mechanism issues and challenges exist. As a result, NASA GRC and Aerojet initiated and completed design changes to the EM thruster to alleviate encountered issues and challenges. In addition, the HiVHAc project is leveraging power processing unit (PPU) developments by Aerojet and by NASA’s Small Business Initiative Research Program. This includes evaluating performance of a wide-output range brassboard PPU that can process input voltages between 80 and 160 volts and is capable of output voltages between 200 and 700 V. Finally, the HiVHAc project has leveraged xenon feed system development by the Science Mission Directorate’s In Space Propulsion Technology Program. The HiVHAc project and Air Force Research Laboratory are funding the development of the next generation of light-weight, low-power consumption, and small-footprint xenon feed system. The unit, designated xenon flow control module, is manufactured by VACCO and will be delivered to NASA GRC in September 2011.

With the completion of myriad genome sequencing projects, genetic bioengineering has expanded into many applications including the integrated analysis of complex pathways, the construction of new biological parts and the redesign of existing, natural biological systems. All these areas require the precise and concerted assembly of multiple DNA fragments of various sizes, including chromosomes, and the fine-tuning of gene expression levels and protein activity. Current commercial cloning products are not robust enough to support the assembly of very large or very small genetic elements or a combination of both. In addition, current strategies are not flexible enough to allow further modifications to the original design without having to undergo complicated cloning strategies. Here, we present a set of protocols that allow the seamless, simultaneous, flexible, and highly efficient assembly of genetic material, designed for a wide size dynamic range (10s to 100,000s base pairs). The assembly can be performed either in vitro or within the living cells and the DNA fragments may or may not share homology at their ends. A novel site-directed mutagenesis approach enhanced by in vitro recombineering is also presented.

Since 2001, the In-Space Propulsion Technology (ISPT) project has been developing and delivering in-space propulsion technologies that will enable or enhance NASA robotic science missions. These in-space propulsion technologies are applicable, and potentially enabling, for future NASA flagship and sample return missions currently being considered, as well as having broad applicability to future competed mission solicitations. The high-temperature Advanced Material Bipropellant Rocket (AMBR) engine providing higher performance for lower cost was completed in 2009. Two other ISPT technologies are nearing completion of their technology development phase: 1) NASA's Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6–7 kW throttle-able gridded ion system; and 2) Aerocapture technology development with investments in a family of thermal protection system (TPS) materials and structures; guidance, navigation, and control (GNC aerothermal effect models: and atmospheric models for Earth, Titan, Mars and Venus. This paper provides status of the technology development, applicability, and availability of in-space propulsion technologies that have recently completed their technology development and will be ready for infusion into NASA's Discovery, New Frontiers, Science Mission Directorate (SMD) Flagship, and Exploration technology demonstration missions.12

In 2009, the In-Space Propulsion Technology (ISPT) program was tasked to start development of propulsion technologies that would enable future sample return missions. Sample return missions can be quite varied, from collecting and bringing back samples of comets or asteroids, to soil, rocks, or atmosphere from planets or moons. As a result, ISPT's propulsion technology development needs are also broad, and include: 1) Sample Return Propulsion (SRP), 2) Planetary Ascent Vehicles (PAV), 3) Multi-mission technologies for Earth Entry Vehicles (MMEEV), and 4) Systems/mission analysis and tools that focuses on sample return propulsion. The SRP area includes electric propulsion for sample return and low cost Discovery-class missions, and propulsion systems for Earth Return Vehicles (ERV) including transfer stages to the destination. Initially the SRP effort will transition on-going work on a High-Voltage Hall Accelerator (HIVHAC) thruster into developing a full HIVHAC system. SRP will also leverage recent lightweight propellant-tanks advancements and develop flight-qualified propellant tanks with direct applicability to the Mars Sample Return (MSR) mission and with general applicability to all future planetary spacecraft. ISPT's previous aerocapture efforts will merge with earlier Earth Entry Vehicles developments to form the starting point for the MMEEV effort. The first task under the Planetary Ascent Vehicles (PAV) effort is the development of a Mars Ascent Vehicle (MAV). The new MAV effort will leverage past MAV analysis and technology developments from the Mars Technology Program (MTP) and previous MSR studies. This paper will describe the state of ISPT project's propulsion technology development for future sample return missions.12

With the completion of myriad genome sequencing projects, genetic bioengineering has expanded into many applications including the integrated analysis of complex pathways, the construction of new biological parts and the redesign of existing, natural biological systems. All these areas require the precise and concerted assembly of multiple DNA fragments of various sizes, including chromosomes, and the fine-tuning of gene expression levels and protein activity. Current commercial cloning products are not robust enough to support the assembly of very large or very small genetic elements or a combination of both. In addition, current strategies are not flexible enough to allow further modifications to the original design without having to undergo complicated cloning strategies. Here, we present a set of protocols that allow the seamless, simultaneous, flexible, and highly efficient assembly of genetic material, designed for a wide size dynamic range (10s to 100,000s base pairs). The assembly can be performed either in vitro or within the living cells and the DNA fragments may or may not share homology at their ends. A novel site-directed mutagenesis approach enhanced by in vitro recombineering is also presented.

Membrane-associated proteins and protein complexes account for approximately a third or more of the proteins in the cell (1, 2). These complexes mediate essential cellular processes; including signal transduc-tion, transport, recognition, bioenergetics and cell-cell communication. In general, membrane proteins are challenging to study because of their insolubility and tendency to aggregate when removed from their protein lipid bilayer environment. This chapter is focused on describing a novel method for producing and solubilizing membrane proteins that can be easily adapted to high-throughput expression screening. This process is based on cell-free transcription and translation technology coupled with nanolipoprotein par ticles (NLPs), which are lipid bilayers confined within a ring of amphipathic protein of defined diameter. The NLPs act as a platform for inserting, solubilizing and characterizing functional membrane proteins. NLP component proteins (apolipoproteins), as well as membrane proteins can be produced by either traditional cell-based or as discussed here, cell-free expression methodologies.

The paucity of membrane protein science reflects the hurdles that these proteins impose on their expression and purification. Expression of membrane proteins in vivo frequently results in cell toxicity, protein aggregation, misfolding, and low yield. Vesicle preparation, detergent extraction, and membrane protein reconstitution into liposomes are processes that inexorably lead to constraints on protein accessibility, surface immobilization, and activity assays. We report a cell-free protein expression approach for expressing and inserting integral membrane proteins into water soluble particles (brand name MembraneMaxTM, offered tag-free or histidine tagged) composed of a phospholipid membrane bilayer surrounded by a scaffold protein. The method circumvents the need of extracting and reconstituting the product into membrane vesicles. Moreover, the planar nature of the membrane support makes the protein freely accessible from both sides of the lipid bilayer.

We report a cell-free approach for expressing and inserting integral membrane proteins into water-soluble particles composed of discoidal apolipoprotein−lipid bilayers. Proteins are inserted into the particles, circumventing the need of extracting and reconstituting the product into membrane vesicles. Moreover, the planar nature of the membrane support makes the protein freely accessible from both sides of the lipid bilayer. Complexes are successfully purified by means of the apoplipoprotein component or by the carrier protein. The method significantly enhances the solubility of a variety of membrane proteins with different functional roles and topologies. Analytical assays for a subset of model membrane proteins indicate that proteins are correctly folded and active. The approach provides a platform amenable to high-throughput structural and functional characterization of a variety of traditionally intractable drug targets.

This paper presents a novel learning model CLARION, which is a hybrid model based on the two-level approach proposed by Sun. The model integrates neural, reinforcement, and symbolic learning methods to perform on-line, bottom-up learning (i.e., learning that goes from neural to symbolic representations). The model utilizes both procedural and declarative knowledge (in neural and symbolic representations, respectively), tapping into the synergy of the two types of processes. It was applied to deal with sequential decision tasks. Experiments and analyzes in various ways are reported that shed light on the advantages of the model.

ABLE Engineering, Inc. (ABLE), in collaboration with the NASA Glenn Research Center (GRC), Jet Propulsion Laboratory (JPL), and EMCORE Photovoltaics (EPV), has been selected for the NASA New Millennium Program (NMP) Space Technology 8 (ST8) Study Phase project to develop and potentially flight validate a state-of-the-art solar array system called: "next generation UltraFlex" NGU is a highly evolved and scaled version of the previously flight qualified Mars 01-Lander UltraFlex and employs many advanced technologies. The NGU system promises very high specific power (175 W/g - 220 W/kg BOL), compact storage volume (>33 kW/m/sup 3/), high reliability, scalability beyond 7 kW wing sizes, and operational capability for standard, high voltage, multi-A.U., and/or high temperature applications. Key technology maturation activities performed (deployment kinematics, deployed dynamics, and power production/survivability) that demonstrate TRL 4+ achievement will be presented. NGU design, development, analysis, and hardware activities are presented. NGU subsystem and system level experimental tests/results and model correlation will be presented. NGU technology scale-up performance to 7 kW wing sizes will also be addressed.

Chromosomal amplifications and deletions are critical components of tumorigenesis and DNA copy-number variations also correlate with changes in mRNA expression levels. Genome-wide microarray comparative genomic hybridization (CGH) has become an important method for detecting and mapping chromosomal changes in tumors. Thus, the ability to detect twofold differences in fluorescent intensity between samples on microarrays depends on the generation of high-quality labeled probes. To enhance array-based CGH analysis, a random prime genomic DNA labeling method optimized for improved sensitivity, signal-to-noise ratios, and reproducibility has been developed. The labeling system comprises formulated random primers, nucleotide mixtures, and notably a high concentration of the double mutant exo-large fragment of DNA polymerase I (exo-Klenow). Microarray analyses indicate that the genomic DNA-labeled templates yield hybridization signals with higher fluorescent intensities and greater signal-to-noise ratios and detect more positive features than the standard random prime and conventional nick translation methods. Also, templates generated by this system have detected twofold differences in gene copy number between male and female genomic DNA and identified amplification and deletions from the BT474 breast cancer cell line in microarray hybridizations. Moreover, alterations in gene copy number were routinely detected with 0.5 microg of genomic DNA starting sample. The method is flexible and performs efficiently with different fluorescently labeled nucleotides. Application of the optimized CGH labeling system may enhance the resolution and sensitivity of array-based CGH analysis in cancer and medical genetic studies.

During the past three years the team of The Aerospace Corporation, Lockheed Martin Space Systems, NASA Glenn Research Center, and ILC Dover LP have been developing a multifunctional inflatable structure for the PowerSphere concept under contract with NASA (NAS3-01115). The PowerSphere attitude insensitive solar power-generating microsatellite, which could be used for many different space and Earth science purposes as discussed elsewhere, is ready for further refinement and flight demonstration. The project culminated during the third year with the manufacturing of the Powersphere Engineering Development Unit (EDU). One hemisphere of the EDU system was tested for packing and deployment and was subsequently rigidized. The other hemisphere was packed and stored for future testing in an uncured state. Both cured and uncured hemisphere components were delivered to NASA Glenn Research Center for thermal cycle testing and long term storage respectively. This paper will discuss the design, manufacturing, and thermal cycle testing of the PowerSphere EDU. The program also had a significant Education Outreach segment that will also be discussed.

ABLE Engineering, Inc. (ABLE), in collaboration with the NASA Glenn Research Center (GRC), Jet Propulsion Laboratory (JPL), and EMCORE photovoltaics (EPV), has been selected for the NASA New Millennium Program (NMP) Space Technology 8 (ST8) project to develop and flight validate a state-of-the-art solar array system. The "next generation UltraFlex" (NGU) system is a highly-evolved and large-scaled version of the previously flight qualified Mars 01-Lander UltraFlex and employs many advanced technologies. The NGU system promises very high specific power (175 W/g-220 W/kg BOL), compact stowage volume (>33 kW/m/sup 3/), high reliability, scalability beyond 7 kW wing sizes, and operational capability for standard, high voltage, multi-A.U., and/or high temperature applications. A detailed overview of the ST8 NGU technology in-space validation program is presented. Key technology maturation activities performed (deployment kinematics, deployed dynamics, and power production/survivability) that demonstrate TRL 4+ achievement will be discussed. Completed design, development, analysis, and NGU hardware build (components, subsystems and systems), and test activities are presented. NGU hardware experimental test results will be presented and model correlations will be shown. Continued ST8 NGU technology development plans, maturation approach to increase readiness level (TRL 4+ to TRL 7/8), and planned flight experiment details are also described.

The Aerospace Corporation, NASA Glenn Research Center, Lockheed-Martin, and ILC Dover over the past two years have been engaged in developing a Multifunctional Inflatable Structure for the PowerSphere Concept under contract with NASA (NAS3-01115). The PowerSphere concept consists of a relatively large spherical solar array, which would be deployed from a micro satellite. 1–8 The PowerSphere structure and the deployment method was patented by the Aerospace Corporation (U.S. Patent Numbers 6,284,966 B1 and 6,318,675). The work on this project has resulted in a number of technological innovations in the state of the art for integrating flexible thin-film solar cells with flex circuit harness technology and inflatable ultraviolet-light-rigidizable structures.

The sta:us of development of a Direct Drive Ha!! Thruster System is presented. 13 the first part. a s:udy of the impacts to spacecraft systems and mass benefits of a direct-drive architecture is reviewed. The study initially examines four cases of SPT-100 and BPT-4000 Hall thrusters used for north-south station keeping on an EXPRESS-like geosynchronous spacecraft and for primary propulsion for a Deep Space- 1 based science spacecraft. The study is also extended the impact of direct drive on orbit raising for higher power geosynchronous spacecraft and on other deep space missions as a function of power and delta velocity. The major system considerations for accommodating a direct drive Hall thruster are discussed, including array regulation, system grounding, distribution of power to the spacecraft bus, and interactions between current-voltage characteristics for the arrays and thrusters. The mass benefit analysis shows that, for the initial cases, up to 42 kg of dry mass savings is attributable directly to changes in the propulsion hardware. When projected mass impacts of operating the arrays and the electric power system at 300V are included, up to 63 kg is saved for the four initial cases. Adoption of high voltage lithium ion battery technology is projected to further improve these savings. Orbit raising of higher powered geosynchronous spacecraft, is the mission for which direct drive provides the most benefit, allowing higher efficiency electric orbit raising to be accomplished in a limited period of time, as well as nearly eliminating significant power processing heat rejection mass. The total increase in useful payload to orbit ranges up to 278 kg for a 25 kW spacecraft, launched from an Atlas IIA. For deep space missions, direct drive is found to be most applicable to higher power missions with delta velocities up to several km/s , typical of several Discovery-class missions. In the second part, the status of development of direct drive propulsion power electronics is presented. The core of this hardware is the heater-keeper-magnet supply being qualified for the BPT-4000 by Aerojet. A breadboard propulsion power unit is in fabrication and is scheduled for delivery late in 2003.

We present a learning algorithm for two player stochastic games. The algorithm generates optimal deterministic finite automata (DFA) strategies against opponents who can be modeled by probabilistic action automata. The algorithm generates dynamic history trees based on statistical tests to eliminate state aliasing. Experiments are conducted in an iterated prisoner's dilemma environment.

To develop autonomous agents for sequential decision tasks in a highly reactive fashion, we present a learning model CLARION, which is a hybrid connectionist model based on the two-level approach proposed in the CONSYDERR architecture. The model learns and utilises procedural and declarative knowledge, tapping into the synergy of the two types of processes (subconceptual and conceptual). It unifies neural, reinforcement, and symbolic methods to perform online, bottom-up learning. Experiments in various situations are reported that shed light on the working of the model and demonstrate the performance advantages of the model.

Although our previous model CLARION has shown some measure of success in reactive sequential decision making tasks by utilizing a hybrid architecture which uses both procedural and declarative learning, it suffers from a number of problems because of its use of backpropagation networks. CLARION-RBF is a more parsimonious architecture that remedies some of the problems exhibited in CLARION by utilizing RBF Networks. CLARION-RBF is also capable of learning reactive procedures, and can have high level symbolic knowledge extracted and applied.

To deal with reactive sequential decision tasks, we present a learning model CLARION, which is a hybrid connectionist model consisting of both localist and distributed representations, based on the two-level approach proposed in Sun (1995). The model learns and utilizes procedural and declarative knowledge, tapping into the synergy of the two types of processes. It unifies neural, reinforcement, and symbolic methods to perform online, bottom-up learning. Experiments in various situations are reported that shed light on the working of the model.

Shaping is a potentially powerful tool in reinforcement learning applications. Shaping often fails to function effectively because of a lack of understanding about its effects when applied in reinforcement learning settings and the use of inadequate algorithms in its implementation. Due to these difficulties current shaping techniques require some form of manual intervention. We examine some of the principles involved in shaping and present a new algorithm for automatic transferral of knowledge, which uses the Q-values established in a previous task to guide exploration in the learning of a new task. This algorithm is applied to two different but related robot navigation tasks.

We focus on the task transfer in reinforcement learning and specifically in Q-learning. There are three main model free methods for performing task transfer in Q-learning: direct transfer, soft transfer and memory-guided exploration. In direct transfer, the Q-values from a previous task are used to initialize the Q-values of the next task. The soft transfer initializes the Q-values of the new task with a weighted average of the standard initialization value and the Q-values of the previous task. In memory-guided exploration the Q-values of previous tasks are used as a guide in the initial exploration of the agent. The weight that the agent gives to its past experience decreases over time. We explore stability issues related to the off-policy nature of memory-guided exploration and compare memory-guided exploration to soft transfer and direct transfer in three different environments.

This paper discusses learning in hybrid models that goes beyond simple classification rule extraction from backpropagation networks. Although simple rule extraction has received a lot of research attention, we need to further develop hybrid learning models that learn autonomously and acquire both symbolic and subsymbolic knowledge. It is also necessary to study autonomous learning of both subsymbolic and symbolic knowledge in integrated architectures. This paper will describe planning knowledge extraction from neural reinforcement learning that goes beyond extracting simple rules. It includes two approaches towards extracting planning knowledge: the extraction of symbolic rules from neural reinforcement learning, and the extraction of complete plans. This work points to a general framework for achieving the subsymbolic to symbolic transition in an integrated autonomous learning framework.

For dealing with reactive sequential decision tasks, a learning model Clarion was developed, which is a hybrid connectionist model consisting of both localist (symbolic) and distributed representations, based on the two-level approach proposed in Sun (1995). The model learns and utilizes procedural and declarative knowledge, tapping into the synergy of the two types of processes. It unifies neural, reinforcement, and symbolic methods to perform on-line, bottom-up learning (from subsymbolic to symbolic knowledge). Experiments in various situations shed light on the working of the model. Its theoretical implications in terms of symbol grounding are also discussed.

Publisher Summary Different from existing models of skill learning that use a top-down approach—that is, from declarative knowledge to procedural knowledge or from explicit knowledge to implicit knowledge—this chapter proposes a bottom-up approach toward skill learning, which goes from procedural to declarative knowledge. The approach is demonstrated in the chapter using the CLARION (connectionist learning with adaptive rule induction online) model. The model based on the two-level dual-representation framework proposed that learns both types of knowledge in a bottom-up fashion by integrating connectionist, reinforcement, and symbolic learning methods to perform online learning and by using a combination of localist and distributed representation. It taps into the synergy of the two types of processes. Analyses of the literature on implicit versus explicit learning as well as other types of skill acquisition, including those in developmental psychology, are carried out to highlight the cognitive plausibility of our approach and its fit with human data. This chapter reviews human experiments that involve bottom-up skill learning while also describing bottom-up skill learning, as captured in a (simplified) computational model of the bottom-up approach, based on many related empirical and theoretical considerations. The chapter analyzes the approach (and especially the model) in terms of its ability to support important phenomena in bottom-up skill learning. The chapter highlights the commonalities and differences between the present approach and existing models of skill learning.

The ASM International Ambassador Program (IAP) has become an invaluable mechanism for developing stronger and more engaging ties with the international microbiology community. Ambassadors serve as ASM representatives to microbiology communities around the world and a local contact for international members that provide them with a voice in the Society. This channel of communication enables ASM to connect even the most distant members with the powerful network of 43,000 ASM members. Today, Ambassadors have been appointed to all 20 ASM regions through a competitive selection process that includes nominations by multiple ASM members. The position has become highly prestigious, and many of our Ambassadors have held leadership positions within their national microbiology society.

The 5 kW Express/T-160E Hall Effect Thruster System (HETS) flight demonstration, by far the highest power HETS ever to be flown in space to date, will accomplish multiple objectives with its operational flight in early 2000. This very low cost, near-term demonstration will validate high power HETS system and component performance in a backup stationkeeping role on a Russian Communications Satellite, Express-A4 To aadress HETS user concerns, interactions data between this system and Express-A3 systems will be gathered analyzed and reported. The T-16OEplume will be characterized in space to validate ground-based experimental data In addition to the flight demonstration, a long-duration ground test will complement the in-space demonstration of the T-160E system for future high-power HETS applications. This project also provides a unique opportunity to work jointly with the only HETS user in the world today (Scientific Production Association of Applied Mechanics (NPO-PM), Krasnoyarsk, Russia) and will yield significant knowledge associated with high power HETS integration aed operations in addition to the in-space demonstration on Express-AR The original Express/T-16OE sponsor, the Ballistic Missile Defense Organization (BMDO), is funding the delivery of the ground qua&d T-160E HET system. The NASA MSFC Future-X Pathfmder Program Ofice is now providing additional funding to leverage the significant investmentprovided by BMDO, thereby enabling original project goats to be achieved in a&&ion to enhancing the in-space flight demonstration technology return. The project has just successfully completed a systemlevel Critical Design Review (CDR) and is proceeding with flight system fabrication and test activities.

Ovarian carcinomas are thought to arise in the ovarian surface epithelium (OSE). Although this tissue forms a simple epithelial covering on the ovarian surface, OSE cells exhibit some mesenchymal characteristics and contain little or no E-cadherin. However, E-cadherin is present in metaplastic OSE cells that resemble the more complex epithelia of the oviduct, endometrium and endocervix, and in primary epithelial ovarian carcinomas. To determine whether E-cadherin was a cause or consequence of OSE metaplasia, we expressed this cell-adhesion molecule in simian virus 40-immortalized OSE cells. In these cells the exogenous E-cadherin, all three catenins, and F-actin localized at sites of cell–cell contact, indicating the formation of functional adherens junctions. Unlike the parent OSE cell line, which had undergone a typical mesenchymal transformation in culture, E-cadherin-expressing cells contained cytokeratins and the tight-junction protein occludin. They also formed cobblestone monolayers in two-dimensional culture and simple epithelia in three-dimensional culture that produced CA125 and shed it into the culture medium. CA125 is a normal epithelial-differentiation product of the oviduct, endometrium, and endocervix, but not of normal OSE. It is also a tumor antigen that is produced by ovarian neoplasms and by metaplastic OSE. Thus, E-cadherin restored some normal characteristics of OSE, such as keratin, and it also induced epithelial-differentiation markers associated with weakly preneoplastic, metaplastic OSE and OSE-derived primary carcinomas. The results suggest an unexpected role for E-cadherin in ovarian neoplastic progression.

Composite process/product development relies on both process monitoring information and nondestructive evaluation measurements for determining application suitability. In the past these activities have been performed and analyzed independently. Our present approach is to present the process monitoring and NDE data together in a data fusion workstation. This methodology leads to final product acceptance based on a combined process monitoring and NDE criteria. The data fusion work station combines process parameter and NDE data in a single workspace enabling all the data to be used in the acceptance/rejection decision process. An example application is the induction welding process, a unique joining method for assembling primary composite structure, that offers significant cost and weight advantages over traditional fasted structure. The determination of the required time, temperature and pressure conditions used in the process to achieve a complete weld is being aided by the use of ultrasonic inspection techniques. Full waveform ultrasonic inspection data is employed to evaluate the quality of spar cap to skin fit, an essential element of the welding process, and is processed to find a parameter that can be used for weld acceptance. Certification of the completed weld incorporates the data fusion methodology.

Bacterial alkaline phosphatases (APases), except those isolated from Bacillus licheniformis, are approximately 45-kDa proteins while eucaryotic alkaline phosphatases are 60 kDa. To answer the question of whether the apparent 60-kDa alkaline phosphatase from Bacillus licheniformis accurately reflected the size of the protein, the entire gene was analyzed. DNA sequence analysis of the alkaline phosphatase I (APaseI) gene of B. licheniformis MC14 indicated that the gene could code for a 60-kDa protein of 553 amino acids. The deduced protein sequence of APaseI showed about 32% identity to those of B. subtilis APase III and IV and had apparent sequence homologies in the core structure and active sites that are conserved among APases of various sources. The extra carboxy-terminal sequence of APaseI, which made the enzyme bigger than other procaryotic APases, was not homologous to those of eucaryotic APases. The amino acid composition of APaseI was most similar to that of salt-dependent APase among the isozymes of B. licheniformis MC14. Another open reading frame of 261 amino acids was present 142 nucleotide upstream of the APaseI gene and its predicted amino acid sequence showed 68% identity to that of glucose dehydrogenase of B. megaterium.

The Pulsed Plasma Thruster (PPT) Space Demonstration Program will characterize the performance of an experimental PPT as an orbit raising propulsion system with a 25% reduction in dry mass and twice the power of the LES 8/9 PPT. The project is a partnership of the USAF Phillips Laboratory and NASA Lewis Research Center. The PPT is manifested on the MightySat II.1 satellite scheduled for launch in January, 2000. An extensive breadboard PPT testing program is underway and data from those tests will be used to finalize the design of the flight version PPT. A plume diagnostic experiment (PDE) will be used to characterize contamination rates and effects on surface thermo-optical properties due to PPT plume contamination. These experiments will then undergo full space qualification testing prior to integration with the MightySat II.1 spacecraft.

The International Education Committee (IEC), formerly the International Microbiological Education Committee (IMEC), held a strategic planning retreat from 26–27 August 2006 at ASM Headquarters in Washington, D.C. Participants traveled from across the United States and abroad to develop a new strategic plan for 2006–2009 that reflects the current educational and training needs of the international microbiological community. Newly appointed IEC Chair Linda Kenney led the retreat with the participation of 16 IEC members, board liaisons, committee chairs, officers, and ASM staff. The diverse background of attendees, representing seven countries including South Africa, India, Mexico, Argentina, Panama, China, and Nigeria, ensure the international microbiological community is effectively and appropriately served.

On-board propulsion systems continue to represent a major spacecraft mass driver across a wide range of missions. Recent trends toward the use of smaller launch vehicles and very ambitious missions increase the leverage of onboard propulsion with respect to overall mission performance. Based on known and anticipated propulsion system requirements, the NASA On-Board Propulsion Program (OBP) initiated an aggressive program to develop advanced pulsed plasma thruster (PPT) technology for a broad spectrum of near and far term missions. To accomplish this, several generations of systems are envisioned for functions ranging from small satellite insertions to precision positioning for high resolution imaging. At present, efforts are in progress to develop technologies for two nearterm flight demonstrations. First, a PPT system developed to provide propulsive attitude control will be tested on NASA's Earth Observer 1, the second technology demonstrator spacecraft scheduled to fly under the NASA New Millennium program (1999). Next, a PPT system will be used to raise the orbit of MightySat III, an Air Force spacecraft scheduled for launch in early 2000. The OBP is partnered closely with the Primex Aerospace Company and the spacecraft host organizations (Goddard Space Flight Center and the Air Force Phillips Laboratory for EO-1 and MightySat, respectively) to assure the development, demonstration, and delivery of PPT hardware that meets all mission requirements. In addition to the EO-1 and MightySat efforts, the OBP also sponsors reseach and technology efforts aimed at technology for precision positioning and formation flying of distributed spacecraft for applications such as high resolution imaging. The program is also actively exploring technology requirements for future system miniaturization for microspacecraft. In addition to industry, the program is also partnered with several academic institutions and is leveraging the fundamental research efforts on-going under Air Force sponsorship. This paper provides an overview of NASA's activities in the area of PPT system development with an emphasis on recent progress and program directions.

James S. Sovey, John A. Hamley, Thomas W. Haag, Michael J. Patterson, Eric J. Pencil,Todd T. Peterson, Luis R. Pinero, John L. Power, Vincent K. Rawlin, and Charles J. SarmientoNASA Lewis Research Center, Cleveland, OhioJohn R. Anderson, Raymond A. Becker, John R. Brophy, and James E. PolkJet Propulsion Laboratory, Pasadena, CaliforniaGerald Benson, Thomas A. Bond, G. I. Cardwell, Jon A. Christensen, Kenneth J. Freick,David J. Hamel, Stephen L. Hart, John McDowell, Kirk A. Norenberg, T. Keith Phelps,Ezequiel Solis, and Harold YostHughes Electron Dynamics Division, Torrance, CaliforniaMichael MatrangaSpectrum Astro Incorporated, Gilbert, ArizonaPrepared for the33rd Joint Propulsion Conference and Exhibitcosponsored by AIAA, ASME, SAE, and ASEESeattle, Washington, July 6-9, 1997National Aeronautics andSpace AdministrationLewis Research Center

In order to develop versatile agents that learn in situated contexts and generalize resulting knowledge to different environments, we explore the possibility of learning both procedural and declarative knowledge in a hybrid connectionist architecture. The architecture, CLARION, is based on the two-level idea proposed earlier by the authors. The architecture integrates reactive routines, rules, learning, and decision-making in a unified framework, and structures different learning components synergistically.

Background G protein coupled receptors (GPCRs) represent the largest family of membrane proteins in the human genome and the richest source of targets for the pharmaceutical industry. A major limitation to characterizing GPCRs has been the difficulty in developing high-level heterologous expression systems that are cost effective. Reasons for these difficulties include inefficient transport and insertion in the plasma membrane and cytotoxicity. Additionally, GPCR purification requires detergents, which have a negative effect on receptor yields and stability. Results Here we report a detergent-free cell-free protein expression-based method to obtain pharmacologically active GPCRs in about 2 hours. Our strategy relies on the co-translational insertion of modified GPCRs into nanometer-sized planar membranes. As a model we employed an engineered β2-adrenergic receptor in which the third intracellular loop has been replaced with T4 lysozyme (β2AR -T4L). We demonstrated that nanolipoprotein particles (NLPs) are necessary for expression of active β2AR -T4L in cell-free systems. The binding specificity of the NLP- β2AR-T4L complex has been determined by competitive assays. Our results demonstrate that β2AR-T4L synthesized in vitro depends on similar oxidative conditions as those required by an in vivo-expressed receptor. Conclusions Although the activation of β2AR-T4L requires the insertion of the T4 lysozyme sequence and the yield of that active protein limited, our results conceptually prove that cell-free protein expression could be used as a fast approach to express these valuable and notoriously difficult-to-express proteins.

Resonance light-scattering particles for ultra-sensitive detection of nucleic acids on microarrays