A-2000: Close air support aircraft design team

The US Air Force is currently faced with the problem of providing adequate close air support for ground forces. Air response to troops engaged in combat must be rapid and devastating due to the highly fluid battle lines of the future. The A-2000 is the result of a study to design an aircraft to deliver massive fire power accurately. The low cost A-2000 incorporates: large weapons payload; excellent maneuverability; all weather and terrain following capacity; redundant systems; and high survivability

Genetic mapping and legume synteny of aphid resistance in African cowpea (Vigna unguiculata L. Walp.) grown in California.

The cowpea aphid Aphis craccivora Koch (CPA) is a destructive insect pest of cowpea, a staple legume crop in Sub-Saharan Africa and other semiarid warm tropics and subtropics. In California, CPA causes damage on all local cultivars from early vegetative to pod development growth stages. Sources of CPA resistance are available in African cowpea germplasm. However, their utilization in breeding is limited by the lack of information on inheritance, genomic location and marker linkage associations of the resistance determinants. In the research reported here, a recombinant inbred line (RIL) population derived from a cross between a susceptible California blackeye cultivar (CB27) and a resistant African breeding line (IT97K-556-6) was genotyped with 1,536 SNP markers. The RILs and parents were phenotyped for CPA resistance using field-based screenings during two main crop seasons in a 'hotspot' location for this pest within the primary growing region of the Central Valley of California. One minor and one major quantitative trait locus (QTL) were consistently mapped on linkage groups 1 and 7, respectively, both with favorable alleles contributed from IT97K-556-6. The major QTL appeared dominant based on a validation test in a related F2 population. SNP markers flanking each QTL were positioned in physical contigs carrying genes involved in plant defense based on synteny with related legumes. These markers could be used to introgress resistance alleles from IT97K-556-6 into susceptible local blackeye varieties by backcrossing

Evidence of a discontinuous disk structure around the Herbig Ae star HD 139 614

A new class of pre-main sequence objects has been recently identified as pre-transitional disks. They present near-infrared excess coupled to a flux deficit at about 10 microns and a rising mid-infrared and far-infrared spectrum. These features suggest a disk structure with inner and outer dust components, separated by a dust-depleted region (or gap). We here report on the first interferometric observations of the disk around the Herbig Ae star HD 139614. Its infrared spectrum suggests a flared disk, and presents pre-transitional features,namely a substantial near-infrared excess accompanied by a dip around 6 microns and a rising mid-infrared part. In this framework, we performed a study of the spectral energy distribution (SED) and the mid-infrared VLTI/MIDI interferometric data to constrain thespatial structure of the inner dust disk region and assess its possibly multi-component structure. We based our work on a temperature-gradient disk model that includes dust opacity. While we could not reproduce the SED and interferometric visibilities with a one-component disk, a better agreement was obtained with a two-component disk model composed of an optically thin inner disk extending from 0.22 to 2.3 au, a gap, and an outer temperature-gradient disk starting at 5.6 au. Therefore, our modeling favors an extended and optically thin inner dust component and in principle rules out the possibility that the near-infrared excess originates only from a spatially confined region. Moreover, the outer disk is characterized by a very steep temperature profile and a temperature higher than 300 K at its inner edge. This suggests the existence of a warm component corresponding to a scenario where the inner edge of the outer disk is directly illuminated by the central star. This is an expected consequence of the presence of a gap, thus indicative of a pre-transitional structure.Comment: 14 pages, 6 figure

Bending vibration measurement on rotors by laser vibrometry

A new technique is proposed for noncontact measurement of bending vibration directly from a rotating component. This notoriously difficult and previously unattained measurement is a further development of laser Doppler vibrometry. Simultaneously the technique provides an accurate measure of shaft torsional vibration in situations in which measurements of torsional vibration have shown significant sensitivity to bending vibration. Experimental results validate the theory developed, and a conservative estimate of the minimum measurable bending vibration is made at 20 millidegrees

HD139614: the interferometric case for a group-Ib pre-transitional young disk

The Herbig Ae star HD 139614 is a group-Ib object, which featureless SED indicates disk flaring and a possible pre-transitional evolutionary stage. We present mid- and near-IR interferometric results collected with MIDI, AMBER and PIONIER with the aim of constraining the spatial structure of the 0.1-10 AU disk region and assess its possible multi-component structure. A two-component disk model composed of an optically thin 2-AU wide inner disk and an outer temperature-gradient disk starting at 5.6 AU reproduces well the observations. This is an additional argument to the idea that group-I HAeBe inner disks could be already in the disk-clearing transient stage. HD 139614 will become a prime target for mid-IR interferometric imaging with the second-generation instrument MATISSE of the VLTI.Comment: SPIE Astronomical Telescopes and Instrumentation conference, June 2014, 11 pages, 7 Figure

Evaluating TERRA-1 MODIS data for discrimination of tropical secondary forest regeneration stages in the Brazilian Legal Amazon

We establish the potential of TERRA-1 Moderate Resolution Imaging Spectrometer (MODIS) data for discriminating and mapping tropical secondary forest regeneration stages in the Brazilian Legal Amazon, in terms of both their age and pathway. In using MODIS data, many difficulties encountered in local to regional scale mapping and discrimination of regeneration stage using NOAA Advanced Very High Resolution Radiometer (AVHRR) and fine spatial resolution Landsat/SPOT sensor data can be largely overcome

Semantics for Noninterference with Interaction Trees

Noninterference is the strong information-security property that a program does not leak secrets through publicly-visible behavior. In the presence of effects such as nontermination, state, and exceptions, reasoning about noninterference quickly becomes subtle. We advocate using interaction trees (ITrees) to provide compositional mechanized proofs of noninterference for multi-language, effectful, nonterminating programs, while retaining executability of the semantics. We develop important foundations for security analysis with ITrees: two indistinguishability relations, leading to two standard notions of noninterference with adversaries of different strength, along with metatheory libraries for reasoning about each. We demonstrate the utility of our results using a simple imperative language with embedded assembly, along with a compiler into that assembly language

Semantics for Noninterference with Interaction Trees (Artifact)

Noninterference is the strong information-security property that a program does not leak secrets through publicly-visible behavior. In the presence of effects such as nontermination, state, and exceptions, reasoning about noninterference quickly becomes subtle. We advocate using interaction trees (ITrees) to provide compositional mechanized proofs of noninterference for multi-language, effectful, nonterminating programs, while retaining executability of the semantics. We develop important foundations for security analysis with ITrees: two indistinguishability relations, leading to two standard notions of noninterference with adversaries of different strength, along with metatheory libraries for reasoning about each. We demonstrate the utility of our results using a simple imperative language with embedded assembly, along with a compiler into that assembly language