Experimental determination of airplane mass and inertial characteristics

Current practices are evaluated for experimentally determining airplane center of gravity, moments of inertia, and products of inertia. The techniques discussed are applicable to bodies other than airplanes. In pitching- and rolling-moment-of-inertia investigations with the airplane mounted on and pivoted about knife edges, the nonlinear spring moments that occur at large amplitudes of oscillation can be eliminated by using the proper spring configuration. The single-point suspension double-pendulum technique for obtaining yawing moments of inertia, products of inertia, and the inclination of the principal axis provides accurate results from yaw-mode oscillation data, provided that the sway-mode effects are minimized by proper suspension rig design. Rocking-mode effects in the data can be isolated

Comparisons of Predictions of the XB-70-1 Longitudinal Stability and Control Derivatives with Flight Results for Six Flight Conditions

Preliminary correlations of flight-determined and predicted stability and control characteristics of the XB-70-1 reported in NASA TN D-4578 were subject to uncertainties in several areas which necessitated a review of prediction techniques particularly for the longitudinal characteristics. Reevaluation and updating of the original predictions, including aeroelastic corrections, for six specific flight-test conditions resulted in improved correlations of static pitch stability with flight data. The original predictions for the pitch-damping derivative, on the other hand, showed better correlation with flight data than the updated predictions. It appears that additional study is required in the application of aeroelastic corrections to rigid model wind-tunnel data and the theoretical determination of dynamic derivatives for this class of aircraft

Regular Language Distance and Entropy

This paper addresses the problem of determining the distance between two regular languages. It will show how to expand Jaccard distance, which works on finite sets, to potentially-infinite regular languages. The entropy of a regular language plays a large role in the extension. Much of the paper is spent investigating the entropy of a regular language. This includes addressing issues that have required previous authors to rely on the upper limit of Shannon\u27s traditional formulation of channel capacity, because its limit does not always exist. The paper also includes proposing a new limit based formulation for the entropy of a regular language and proves that formulation to both exist and be equivalent to Shannon\u27s original formulation (when it exists). Additionally, the proposed formulation is shown to equal an analogous but formally quite different notion of topological entropy from Symbolic Dynamics -- consequently also showing Shannon\u27s original formulation to be equivalent to topological entropy. Surprisingly, the natural Jaccard-like entropy distance is trivial in most cases. Instead, the entropy sum distance metric is suggested, and shown to be granular in certain situations

Trehalose Is A Chemical Attractant In The Establishment Of Coral Symbiosis

Coral reefs have evolved with a crucial symbiosis between photosynthetic dinoflagellates (genus Symbiodinium) and their cnidarian hosts (Scleractinians). Most coral larvae take up Symbiodinium from their environment; however, the earliest steps in this process have been elusive. Here we demonstrate that the disaccharide trehalose may be an important signal from the symbiont to potential larval hosts. Symbiodinium freshly isolated from Fungia scutaria corals constantly released trehalose (but not sucrose, maltose or glucose) into seawater, and released glycerol only in the presence of coral tissue. Spawning Fungia adults increased symbiont number in their immediate area by excreting pellets of Symbiodinium, and when these naturally discharged Symbiodinium were cultured, they also released trehalose. In Y-maze experiments, coral larvae demonstrated chemoattractant and feeding behaviors only towards a chamber with trehalose or glycerol. Concomitantly, coral larvae and adult tissue, but not symbionts, had significant trehalase enzymatic activities, suggesting the capacity to utilize trehalose. Trehalase activity was developmentally regulated in F. scutaria larvae, rising as the time for symbiont uptake occurs. Consistent with the enzymatic assays, gene finding demonstrated the presence of a trehalase enzyme in the genome of a related coral, Acropora digitifera, and a likely trehalase in the transcriptome of F. scutaria. Taken together, these data suggest that adult F. scutaria seed the reef with Symbiodinium during spawning and the exuded Symbiodinium release trehalose into the environment, which acts as a chemoattractant for F. scutaria larvae and as an initiator of feeding behavior- the first stages toward establishing the coral-Symbiodinium relationship. Because trehalose is a fixed carbon compound, this cue would accurately demonstrate to the cnidarian larvae the photosynthetic ability of the potential symbiont in the ambient environment. To our knowledge, this is the first report of a chemical cue attracting the motile coral larvae to the symbiont

Optical Guidance System /OGS/ for rendezvous and docking Final report

Optical guidance system for Apollo rendezvous and dockin

Defective expression of basement membrane-associated C3d,g in papulonodular basal cell carcinomas

AbstractRecent studies in our laboratory have shown that C3d,g, a 41,000-Da fragment of the third component of complement, is present along the base of the lamina densa and in the sublamina densa region of normal human epidermal basement membrane, but absent from the skin of a patient with congenital C3 deficiency. In studies of human skin, papulonodular basal cell carcinomas have served as a useful model for the investigation of various basement membrane antigens and matrix proteins. To further investigate the presence of C3d,g within epidermal basement membrane as well as examine its relationship with other known basement membrane constituents, we have analyzed serial sections of ten papulonodular basal cell carcinomas by light and immunofluorescence microscopy. In these studies, C3d,g was either absent (N = 9) or minimumly detectable (N = 1) in tumor nest basement membranes. While bullous pemphigoid and KF-1 antigens were absent (N = 6 and N = 3, respectively) or significantly decreased (N = 4 and N = 7, respectively), epidermolysis bullosa acquisita antigen was routinely present though somewhat (N = 3) or moderately decreased (N = 3).Laminin and type IV collagen were expressed normally in all tumor nest basement membranes. All constituents, including C3d,g, were present in adjacent normal epidermal basement membrane of these tumor samples. This study has demonstrated antigenic alterations within each ultrastructural subregion of papulonodular basal cell carcinoma tumor nest basement membranes by identifying the virtual absence of C3d,g (sublamina densa) as well as a significant reduction in KF-1 (lamina densa) and bullous pemphigoid (lamina lucida) antigens. Moreover, the presence of laminin, type IV collagen, and epidermolysis bullosa acquisita antigen in tumor nest basement membranes suggests that these particular constituents neither cleave C3 nor act as essential binding sites for passive incorporation of this complement component in epidermal basement membrane. These studies give additional support to the hypothesis that C3d,g is a previously unrecognized constituent of normal epidermal basement membrane and does not represent passive incorporation of circulating C3 at this site in human skin

Multi-messenger astronomy of gravitational-wave sources with flexible wide-area radio transient surveys

We explore opportunities for multi-messenger astronomy using gravitational waves (GWs) and prompt, transient low-frequency radio emission to study highly energetic astrophysical events. We review the literature on possible sources of correlated emission of gravitational waves and radio transients, highlighting proposed mechanisms that lead to a short-duration, high-flux radio pulse originating from the merger of two neutron stars or from a superconducting cosmic string cusp. We discuss the detection prospects for each of these mechanisms by low-frequency dipole array instruments such as LWA1, LOFAR and MWA. We find that a broad range of models may be tested by searching for radio pulses that, when de-dispersed, are temporally and spatially coincident with a LIGO/Virgo GW trigger within a \usim 30 second time window and \usim 200 \mendash 500 \punits{deg}^{2} sky region. We consider various possible observing strategies and discuss their advantages and disadvantages. Uniquely, for low-frequency radio arrays, dispersion can delay the radio pulse until after low-latency GW data analysis has identified and reported an event candidate, enabling a \emph{prompt} radio signal to be captured by a deliberately targeted beam. If neutron star mergers do have detectable prompt radio emissions, a coincident search with the GW detector network and low-frequency radio arrays could increase the LIGO/Virgo effective search volume by up to a factor of \usim 2. For some models, we also map the parameter space that may be constrained by non-detections.Comment: 31 pages, 4 figure

A Study of Human Serum Sickness

Twelve patients with bone marrow failure, who were undergoing therapy with daily intravenous infusions of horse antithymocyte globulin, were studied for the development of serum sickness. Eleven of 12 patients developed typical signs and symptoms of serum sickness 8-13 days after the initiation of treatment. These included fever, malaise, cutaneous eruptions, arthralgias, gastrointestinal disturbances, and lymphadenopathy. Eleven of 12 patients developed high levels of circulating immune complexes during serum sickness. All 12 patients also had concomitant decreases of serum C3 and C4 levels. In addition to urticarial and/or morbilliform eruptions, 8 of 11 patients also developed a serpiginous band of erythema along the sides of the fingers, hands, toes, or feet as an early cutaneous sign of serum sickness. Direct immunofluorescence of lesional skin biopsies during serum sickness revealed deposits of immunoglobulin or complement in the walls of small cutaneous blood vessels in 3 of 5 patients. These findings indicate that circulating immune complexes play a central role in the pathophysiology of human serum sickness

Human Bullous Pemphigoid Antigen 2 Transgenic Skin Elicits Specific IgG in Wild-Type Mice

Bullous pemphigoid antigen 2 (BPAG2) is targeted by autoantibodies in patients with bullous pemphigoid (BP), and absent in patients with one type of epidermolysis bullosa (OMIM #226650). A keratin 14 promoter construct was used to produce transgenic (Tg) mice appropriately expressing human BPAG2 (hBPAG2) in murine epidermal basement membrane (BM). Grafts of Tg skin placed on gender-matched, syngeneic wild type (Wt) or major histocompatibility complex I (MHC I)−/− mice elicited IgG that bound human epidermal BM and BPAG2. Production of such IgG in grafted mice was prompt (detectable within 16±2 days), robust (titer ≥1,280), durable (present ≥380 days), and correlated with the involution and loss of Tg skin grafts. MHC II−/− mice grafted with Tg skin did not develop anti-hBPAG2 IgG or graft loss indicating that MHC II:CD4+ T cell interactions were crucial for these responses. Tg skin grafts on Wt mice developed neutrophil-rich infiltrates, dermal edema, subepidermal blisters, and deposits of immunoreactants in epidermal BM. This model shows fidelity to alterations seen in patients with BP, has relevance to immune responses that may arise in patients with epidermolysis bullosa following BPAG2 gene replacement, and can be used to identify interventions that may block production of IgG against proteins in epidermal BM