22,817 research outputs found
Using the LANDSAT data collection system for field geophysics: Operations in the British Virgin Islands
This particular application was to vertical geodesy by tide gauge and tiltmeter on a small desert island in the British Virgin Islands. The performance of the LANDSAT system under potentially marginal circumstances was found to be excellent
Specialization of the rostral prefrontal cortex for distinct analogy processes
Analogical reasoning is central to learning and abstract thinking. It involves using a more familiar situation (source) to make inferences about a less familiar situation (target). According to the predominant cognitive models, analogical reasoning includes 1) generation of structured mental representations and 2) mapping based on structural similarities between them. This study used functional magnetic resonance imaging to specify the role of rostral prefrontal cortex (PFC) in these distinct processes. An experimental paradigm was designed that enabled differentiation between these processes, by temporal separation of the presentation of the source and the target. Within rostral PFC, a lateral subregion was activated by analogy task both during study of the source (before the source could be compared with a target) and when the target appeared. This may suggest that this subregion supports fundamental analogy processes such as generating structured representations of stimuli but is not specific to one particular processing stage. By contrast, a dorsomedial subregion of rostral PFC showed an interaction between task (analogy vs. control) and period (more activated when the target appeared). We propose that this region is involved in comparison or mapping processes. These results add to the growing evidence for functional differentiation between rostral PFC subregions
Low-speed stability and control wind-tunnel investigations of effects of spanwise blowing on fighter flight characteristics at high angles of attack
The effects of spanwise blowing on two configurations representative of current fighter airplanes were investigated. The two configurations differed only in wing planform, with one incorporating a trapezoidal wing and the other a 60 delta wing. Emphasis was on determining the lateral-directional characteristics, particularly in the stall/departure angle-of-attack range; however, the effects of spanwise blowing on the longitudinal aerodynamics were also determined. The-tunnel tests included measurement of static force and forced-oscillation aerodynamic data, visualization of the airflow changes created by the spanwise blowing, and free-flight model tests. The effects of blowing rate, chordwise location of the blowing ports, asymmetric blowing, and blowing on the conventional aerodynamic control characteristics were investigated. In the angle-of-attack regions in which the spanwise blowing substantially improved the wing upper-surface flow field (i.e., provided reattachment of the flow aft of the leading-edge vortex), improvements in both static and dynamic lateral-directional stability were observed. Blowing effects on stability could be proverse or adverse depending on blowing rate, blowing port loaction, and wing planform. Free-flight model tests of the trapezoidal wing confirmed the beneficial effects of spanwise blowing measured in the static and dynamic force tests
Control-system techniques for improved departure/spin resistance for fighter aircraft
Some fundamental information on control system effects on controllability of highly maneuverable aircraft at high angles of attack are summarized as well as techniques for enhancing fighter aircraft departure/spin resistance using control system design. The discussion includes: (1) a brief review of pertinent high angle of attack phenomena including aerodynamics, inertia coupling, and kinematic coupling; (2) effects of conventional stability augmentation systems at high angles of attack; (3) high angle of attack control system concepts designed to enhance departure/spin resistance; and (4) the outlook for applications of these concepts to future fighters, particularly those designs which incorporate relaxed static stability
EOS image data processing system definition study
The Image Processing System (IPS) requirements and configuration are defined for NASA-sponsored advanced technology Earth Observatory System (EOS). The scope included investigation and definition of IPS operational, functional, and product requirements considering overall system constraints and interfaces (sensor, etc.) The scope also included investigation of the technical feasibility and definition of a point design reflecting system requirements. The design phase required a survey of present and projected technology related to general and special-purpose processors, high-density digital tape recorders, and image recorders
Thermodynamics of nuclei in thermal contact
The behaviour of a di-nuclear system in the regime of strong pairing
correlations is studied with the methods of statistical mechanics. It is shown
that the thermal averaging is strong enough to assure the application of
thermodynamical methods to the energy exchange between the two nuclei in
contact. In particular, thermal averaging justifies the definition of a nuclear
temperature.Comment: 9 pages, 1 figur
The phytoplankton of the Gulf of California obtained by the E. W. Scipps in 1939 and 1940
The waters of the Gulf of California are fabulously rich in marine life; they fairly teem with multitudes of fish of both commercial and sport varieties. To maintain these large numbers there must be correspondingly huge crops of their ultimate food-the phytoplankton. And, indeed, it was the enormous quantity of these microscopic plants that gave the Gulf its early and descriptive name-the Vermilion Sea. In 1939 and again in 1940 the E. W. Scripps, research vessel of the Scripps Institution of Oceanography of the University of California, spent several months in these waters and among the data collected on these cruises were quantitative samples of this phytoplankton. It is with these samples that the present report deals
Level density of a Fermi gas and integer partitions: a Gumbel-like finite-size correction
We investigate the many-body level density of gas of non-interacting
fermions. We determine its behavior as a function of the temperature and the
number of particles. As the temperature increases, and beyond the usual
Sommerfeld expansion that describes the degenerate gas behavior, corrections
due to a finite number of particles lead to Gumbel-like contributions. We
discuss connections with the partition problem in number theory, extreme value
statistics as well as differences with respect to the Bose gas.Comment: 5 pages, 1 figure, one figure added, accepted for publication in
Phys. Rev.
A Web/Grid Services Approach for Integration of Virtual Clinical & Research Environments
Clinicans have responsibilities for audit and research, often participating in projects with basic scientist colleagues. Our work in a regional teaching hospital setting involves collaboration with the medical school computer services and builds upon work developed in computer science department as part of the Collaborative Orthopaedic Research Environment (CORE) project[1]. This has established a pilot study for proof of concept work. Users are mapped to a personal profile implemented using XML and a service oriented architecture (SOA)[2,3]. This bridges the e-Health and e-Science domains, addressing some of the basic questions of security and uptake
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Arizona’s Rising STEM Occupational Demands and Declining Participation in the Scientific Workforce: An Examination of Attitudes among African Americans toward STEM College Majors and Careers
According to the Bureau of Labor Statistics (2008), science, technology, engineering, and math (STEM) occupations constitute a growing sector of Arizona’s economy. However, the number of African Americans earning degrees related to these occupations has not kept pace with this growth. Increasing the participation of African Americans in STEM education fields and subsequent related occupations in Arizona is vital to growing and maintaining the state’s economic stature. This objective is made even more compelling given that each year, from 2008– 2018, there are 3,671 projected job openings in STEM fields in Arizona. This study explores the extent to which the attitudes held by African Americans in Arizona toward STEM related majors and careers influence their likelihood of joining the state’s scientific workforce. Our analyses reveal the importance of career consideration, confidence in one’s ability to be successful in a STEM related field, and family support of the pursuit of STEM education and careers.Educatio
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