Delta method, an empirical drag buildup technique

An empirical drag correlation technique was developed from analysis of 19 subsonic and supersonic military aircraft and 15 advanced or supercritical airfoil configurations which can be applied in conceptual and advanced aircraft design activities. The Delta Method may be used for estimating the clean wing drag polar for cruise and maneuver conditions up to buffet onset, and to approximately Mach 2.0. This technique incorporates a unique capability of predicting the off-design performance of advanced or supercritical airfoil sections. The buffet onset limit may also be estimated. The method is applicable to wind tunnel models as well as to full scale configurations. This technique has been converted into a computer code for use on the IBM 360 and CDC 7600 computer facilities at NASA AMES. Results obtained using this method to predict known aircraft characteristics are good and agreement can be obtained within a degree of accuracy judged to be sufficient for the initial processes of preliminary design

RICIS research

The principle focus of one of the RICIS (Research Institute for Computing and Information Systems) components is computer systems and software engineering in-the-large of the lifecycle of large, complex, distributed systems which: (1) evolve incrementally over a long time; (2) contain non-stop components; and (3) must simultaneously satisfy a prioritized balance of mission and safety critical requirements at run time. This focus is extremely important because of the contribution of the scaling direction problem to the current software crisis. The Computer Systems and Software Engineering (CSSE) component addresses the lifestyle issues of three environments: host, integration, and target

Intermanifold similarities in partial photoionization cross sections of helium

Using the eigenchannel R-matrix method we calculate partial photoionization cross sections from the ground state of the helium atom for incident photon energies up to the N=9 manifold. The wide energy range covered by our calculations permits a thorough investigation of general patterns in the cross sections which were first discussed by Menzel and co-workers [Phys. Rev. A {\bf 54}, 2080 (1996)]. The existence of these patterns can easily be understood in terms of propensity rules for autoionization. As the photon energy is increased the regular patterns are locally interrupted by perturber states until they fade out indicating the progressive break-down of the propensity rules and the underlying approximate quantum numbers. We demonstrate that the destructive influence of isolated perturbers can be compensated with an energy-dependent quantum defect.Comment: 10 pages, 10 figures, replacement with some typos correcte

Hyperspherical partial wave calculation for double photoionization of the helium atom at 20 eV excess energy

Hyperspherical partial wave approach has been applied here in the study of double photoionization of the helium atom for equal energy sharing geometry at 20 eV excess energy. Calculations have been done both in length and velocity gauges and are found to agree with each other, with the CCC results and with experiments and exhibit some advantages of the corresponding three particle wave function over other wave functions in use.Comment: 11 pages, 1 figure, submitted to J. Phys B: At. Mol. Opt. Phys; v2 - revised considerably, rewritten using ioplatex clas

Cytochrome oxidase subunit VI of Trypanosoma brucei is imported without a cleaved presequence and is developmentally regulated at both RNA and protein levels

Mitochondrial respiration in the African trypanosome undergoes dramatic developmental stage regulation. This requires co-ordinated control of components encoded by both the nuclear genome and the kinetoplast, the unusual mitochondrial genome of these parasites. As a model for understanding the co-ordination of these genomes, we have examined the regulation and mitochondrial import of a nuclear-encoded component of the cytochrome oxidase complex, cytochrome oxidase subunit VI (COXVI). By generating transgenic trypanosomes expressing intact or mutant forms of this protein, we demonstrate that COXVI is not imported using a conventional cleaved presequence and show that sequences at the N-terminus of the protein are necessary for correct mitochondrial sorting. Analyses of endogenous and transgenic COXVI mRNA and protein expression in parasites undergoing developmental stage differentiation demonstrates a temporal order of control involving regulation in the abundance of, first, mRNA and then protein. This represents the first dissection of the regulation and import of a nuclear-encoded protein into the cytochrome oxidase complex in these organisms, which were among the earliest eukaryotes to possess a mitochondrion

Threshold Laws for the Break-up of Atomic Particles into Several Charged Fragments

The processes with three or more charged particles in the final state exhibit particular threshold behavior, as inferred by the famous Wannier law for (2e + ion) system. We formulate a general solution which determines the threshold behavior of the cross section for multiple fragmentation. Applications to several systems of particular importance with three, four and five leptons (electrons and positrons) in the field of charged core; and two pairs of identical particles with opposite charges are presented. New threshold exponents for these systems are predicted, while some previously suggested threshold laws are revised.Comment: 40 pages, Revtex, scheduled for the July issue of Phys.Rev.A (1998

The Mitochondrial Genome and Transcriptome of the Basal Dinoflagellate Hematodinium sp.: Character Evolution within the Highly Derived Mitochondrial Genomes of Dinoflagellates

The sister phyla dinoflagellates and apicomplexans inherited a drastically reduced mitochondrial genome (mitochondrial DNA, mtDNA) containing only three protein-coding (cob, cox1, and cox3) genes and two ribosomal RNA (rRNA) genes. In apicomplexans, single copies of these genes are encoded on the smallest known mtDNA chromosome (6 kb). In dinoflagellates, however, the genome has undergone further substantial modifications, including massive genome amplification and recombination resulting in multiple copies of each gene and gene fragments linked in numerous combinations. Furthermore, protein-encoding genes have lost standard stop codons, trans-splicing of messenger RNAs (mRNAs) is required to generate complete cox3 transcripts, and extensive RNA editing recodes most genes. From taxa investigated to date, it is unclear when many of these unusual dinoflagellate mtDNA characters evolved. To address this question, we investigated the mitochondrial genome and transcriptome character states of the deep branching dinoflagellate Hematodinium sp. Genomic data show that like later-branching dinoflagellates Hematodinium sp. also contains an inflated, heavily recombined genome of multicopy genes and gene fragments. Although stop codons are also lacking for cox1 and cob, cox3 still encodes a conventional stop codon. Extensive editing of mRNAs also occurs in Hematodinium sp. The mtDNA of basal dinoflagellate Hematodinium sp. indicates that much of the mtDNA modification in dinoflagellates occurred early in this lineage, including genome amplification and recombination, and decreased use of standard stop codons. Trans-splicing, on the other hand, occurred after Hematodinium sp. diverged. Only RNA editing presents a nonlinear pattern of evolution in dinoflagellates as this process occurs in Hematodinium sp. but is absent in some later-branching taxa indicating that this process was either lost in some lineages or developed more than once during the evolution of the highly unusual dinoflagellate mtDNA

Going With the Flow or Against the Grain? The Promise of Vegetation for Protecting Beaches, Dunes, and Barrier Islands From Erosion

Coastlines have traditionally been engineered to maintain structural stability and to protect property from storm‐related damage, but their ability to endure will be challenged over the next century. The use of vegetation to reduce erosion on ocean‐facing mainland and barrier island shorelines – including the sand dunes and beaches on these islands – could be part of a more flexible strategy. Although there is growing enthusiasm for using vegetation for this purpose, empirical data supporting this approach are lacking. Here, we identify the potential roles of vegetation in coastal protection, including the capture of sediment, ecological succession, and the building of islands, dunes, and beaches; the development of wave‐resistant soils by increasing effective grain size and sedimentary cohesion; the ability of aboveground architecture to attenuate waves and impede through‐flow; the capability of roots to bind sediments subjected to wave action; and the alteration of coastline resiliency by plant structures and genetic traits. We conclude that ecological and engineering practices must be combined in order to develop a sustainable, realistic, and integrated coastal protection strategy

Introduction

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69081/2/10.1177_0261927X99018001001.pd