7,397 research outputs found

    Experimental study of wing leading-edge devices for improved maneuver performance of a supercritical maneuvering fighter configuration

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    Wind tunnel tests were conducted to examine the use of wing leading-edge devices for improved subsonic and transonic maneuver performance. These devices were tested on a fighter configuration which utilized supercritical-wing technology. The configuration had a leading-edge sweep of 45 deg and an aspect ratio of 3.28. The tests were conducted at Mach numbers of 0.60 and 0.85 with angles of attack from -0.5 deg to 22 deg. At both Mach numbers, sharp leading-edge flaps produced vortices which greatly altered the flow pattern on the wing and resulted in substantial reductions in drag at high lift. Underwing or pylon-type vortex generators also reduced drag at high lift. The vortex generators worked better at a Mach number of 0.60. The vortex generators gave the best overall results with zero toe-in angle and when mounted on either the outboard part of the wing or at both an outboard location and halfway out the semispan. Both the flaps and the vortex generators had a minor effect on the pitching moment. Fluorescent minitufts were found to be useful for flow visualization at transonic maneuver conditions

    Integrating Viral Hepatitis Screening and Prevention Services into an Urban Chemical Dependency Treatment Facility for American Indians and Alaska Natives

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    American Indian/Alaska Natives (AI/AN) patients at an urban residential chemical dependency treatment center participated in a viral hepatitis prevention project. Project activities integrated into patients’ treatment programs included viral hepatitis and human immunodeficiency virus (HIV) risk factor screening, education and counseling, laboratory testing, and hepatitis A and B vaccination. Of 928 AI/AN admissions, 585 (63%) completed risk factor screening assessment. Of these, 436 (75%) received at least one vaccination, viral hepatitis testing, or both. Of 322 patients tested, 91 (28%) were hepatitis C virus (HCV) antibody positive. Lack of pre-existing immunity to vaccine-preventable viral hepatitis infection was common: 132 (45%) were susceptible to hepatitis A and 224 (70%) were susceptible to hepatitis B infection. Chemical dependency treatment centers serving urban AI/AN provide important opportunities for implementing viral hepatitis prevention programs for high-risk populations and for improving ongoing efforts to reduce the disparate impact of chronic liver disease in AI/ AN people

    From Skew-Cyclic Codes to Asymmetric Quantum Codes

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    We introduce an additive but not F4\mathbb{F}_4-linear map SS from F4n\mathbb{F}_4^{n} to F42n\mathbb{F}_4^{2n} and exhibit some of its interesting structural properties. If CC is a linear [n,k,d]4[n,k,d]_4-code, then S(C)S(C) is an additive (2n,22k,2d)4(2n,2^{2k},2d)_4-code. If CC is an additive cyclic code then S(C)S(C) is an additive quasi-cyclic code of index 22. Moreover, if CC is a module θ\theta-cyclic code, a recently introduced type of code which will be explained below, then S(C)S(C) is equivalent to an additive cyclic code if nn is odd and to an additive quasi-cyclic code of index 22 if nn is even. Given any (n,M,d)4(n,M,d)_4-code CC, the code S(C)S(C) is self-orthogonal under the trace Hermitian inner product. Since the mapping SS preserves nestedness, it can be used as a tool in constructing additive asymmetric quantum codes.Comment: 16 pages, 3 tables, submitted to Advances in Mathematics of Communication

    Matroids and Quantum Secret Sharing Schemes

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    A secret sharing scheme is a cryptographic protocol to distribute a secret state in an encoded form among a group of players such that only authorized subsets of the players can reconstruct the secret. Classically, efficient secret sharing schemes have been shown to be induced by matroids. Furthermore, access structures of such schemes can be characterized by an excluded minor relation. No such relations are known for quantum secret sharing schemes. In this paper we take the first steps toward a matroidal characterization of quantum secret sharing schemes. In addition to providing a new perspective on quantum secret sharing schemes, this characterization has important benefits. While previous work has shown how to construct quantum secret sharing schemes for general access structures, these schemes are not claimed to be efficient. In this context the present results prove to be useful; they enable us to construct efficient quantum secret sharing schemes for many general access structures. More precisely, we show that an identically self-dual matroid that is representable over a finite field induces a pure state quantum secret sharing scheme with information rate one

    Isolation and characterization of the herpes simplex virus 1 terminase complex

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    During herpes simplex virus 1 (HSV-1) infection, empty procapsids are assembled and subsequently filled with the viral genome by means of a protein complex called the terminase, which is comprised of the HSV-1 UL15, UL28, and UL33 proteins. Biochemical studies of the terminase proteins have been hampered by the inability to purify the intact terminase complex. In this study, terminase complexes were isolated by tandem-affinity purification (TAP) using recombinant viruses expressing either a full-length NTAP-UL28 fusion protein (vFH476) or a C-terminally truncated NTAP-UL28 fusion protein (vFH499). TAP of the UL28 protein from vFH476-infected cells, followed by silver staining, Western blotting, and mass spectrometry, identified the UL15, UL28, and UL33 subunits, while TAP of vFH499-infected cells confirmed previous findings that the C terminus of UL28 is required for UL28 interaction with UL33 and UL15. Analysis of the oligomeric state of the purified complexes by sucrose density gradient ultracentrifugation revealed that the three proteins formed a complex with a molecular mass that is consistent with the formation of a UL15-UL28-UL33 heterotrimer. In order to assess the importance of conserved regions of the UL15 and UL28 proteins, recombinant NTAP-UL28 viruses with mutations of the putative UL28 metal-binding domain or within the UL15 nuclease domain were generated. TAP of UL28 complexes from cells infected with each domain mutant demonstrated that the conserved cysteine residues of the putative UL28 metal-binding domain and conserved amino acids within the UL15 nuclease domain are required for the cleavage and packaging functions of the viral terminase, but not for terminase complex assembly

    Environmental Evaluation Report onn Various Completed Channel Improvement Projects in Eastern Arkansas

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    The objective of this report is to evaluate the beneficial and adverse effects that certain channel improvement projects have had on the natural or man-made environments of selected areas in eastern Arkansas. This evaluation will be used as a baseline for determining the immediate and long-term effects that a project may have on the existing environment of the Village Creek Basin
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