257 research outputs found

    Are many radio-selected BL Lacs radio quasars in disguise?

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    We show that a blazar classification in BL Lacs and Flat Spectrum Radio Quasars may not be adequate when it relies solely on the equivalent widths (EWs) of optical lines. In fact, depending on redshift, some strong emission lines can fall in the infrared window and be missed. We selected a sample of BL Lacs with firm redshift identification and good visibility from Paranal. We targeted with the X-shooter spectrograph the five BL Lacs with z > 0.7, i.e., those for which the Halpha line, one of the strongest among blazars, falls outside the optical window and determined the EW of emission lines in both the infrared and optical bands. Two out of five sources show an observed Halpha EW > 5A (one has rest frame EW > 5A) and could be classified as FSRQs by one of the classification schemes used in the literature. A third object is border-line with an observed EW of 4.4 +/- 0.5A. In all these cases Halpha is the strongest emission line detected. The Halpha line of the other two blazars is not detected, but in one case it falls in a region strongly contaminated by sky lines and in the other one the spectrum is featureless. We conclude that a blazar classification based on EW width only can be inaccurate and may lead to an erroneous determination of blazar evolution. This effect is more severe for the BL Lac class, since FSRQs can be misclassified as BL Lacs especially at high redshifts (z > 0.7), where the latter are extremely rare.Comment: 6 pages, 4 ps figures, 2 tables, accepted for publication in MNRA

    Preliminary design characteristics of a subsonic business jet concept employing laminar flow control

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    Aircraft configurations were developed with laminar flow control (LFC) and without LFC. The LFC configuration had approximately eleven percent less parasite drag and a seven percent increase in the maximum lift-to drag ratio. Although these aerodynamic advantages were partially offset by the additional weight of the LFC system, the LFC aircraft burned from six to eight percent less fuel for comparable missions. For the trans-atlantic design mission with the gross weight fixed, the LFC configuration would carry a greater payload for ten percent fuel per passenger mile

    Design of a large span-distributed load flying-wing cargo airplane with laminar flow control

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    A design study was conducted to add laminar flow control to a previously design span-distributed load airplane while maintaining constant range and payload. With laminar flow control applied to 100 percent of the wing and vertical tail chords, the empty weight increased by 4.2 percent, the drag decreased by 27.4 percent, the required engine thrust decreased by 14.8 percent, and the fuel consumption decreased by 21.8 percent. When laminar flow control was applied to a lesser extent of the chord (approximately 80 percent), the empty weight increased by 3.4 percent, the drag decreased by 20.0 percent, the required engine thrust decreased by 13.0 percent, and the fuel consumption decreased by 16.2 percent. In both cases the required take-off gross weight of the aircraft was less than the original turbulent aircraft

    Preliminary design characteristics of a subsonic business jet concept employing an aspect ratio 25 strut braced wing

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    The advantages of replacing the conventional wing on a transatlantic business jet with a larger, strut braced wing of aspect ratio 25 were evaluated. The lifting struts reduce both the induced drag and structural weight of the heavier, high aspect ratio wing. Compared to the conventional airplane, the strut braced wing design offers significantly higher lift to drag ratios achieved at higher lift coefficients and, consequently, a combination of lower speeds and higher altitudes. The strut braced wing airplane provides fuel savings with an attendant increase in construction costs

    Drug resistance in B and non-B subtypes amongst subjects recently diagnosed as primary/recent or chronic HIV-infected over the period 2013–2016: Impact on susceptibility to first-line strategies including integrase strand-transfer inhibitors

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    Objectives To characterize the prevalence of transmitted drug resistance mutations (TDRMs) by plasma analysis of 750 patients at the time of HIV diagnosis from January 1, 2013 to November 16, 2016 in the Veneto region (Italy), where all drugs included in the recommended first line therapies were prescribed, included integrase strand transfer inhibitors (InNSTI). Methods TDRMs were defined according to the Stanford HIV database algorithm. Results Subtype B was the most prevalent HIV clade (67.3%). A total of 92 patients (12.3%) were expected to be resistant to one drug at least, most with a single class mutation (60/68–88.2% in subtype B infected subjectsand 23/24–95.8% in non-B subjects) and affecting mainly NNRTIs. No significant differences were observed between the prevalence rates of TDRMs involving one or more drugs, except for the presence of E138A quite only in patients with B subtype and other NNRTI in subjects with non-B infection. The diagnosis of primary/recent infection was made in 73 patients (9.7%): they had almost only TDRMs involving a single class. Resistance to InSTI was studied in 484 subjects (53 with primary-recent infection), one patient had 143C in 2016, a total of thirteen 157Q mutations were detected (only one in primary/recent infection). Conclusions Only one major InSTI-TDRM was identified but monitoring of TDRMs should continue in the light of continuing presence of NNRTI-related mutation amongst newly diagnosed subjects, sometime impacting also to modern NNRTI drugs recommended in first-line therapy

    Spontaneous immunogenicity of ribosomal P0 protein in patients with benign and malignant breast lesions and delay of mammary tumor growth in P0-vaccinated mice

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    A common carboxyl-terminal epitope (C-22 P0) of the ribosomal P proteins (P0, P1 and P2) was shown to elicit autoantibodies in systemic lupus erythematosus (SLE) and in head and neck cancer patients. In this report we provide evidence for the in vivo immunogenicity of the P0 protein in breast cancer patients. Using recombinant P proteins, we demonstrated that sera from breast carcinoma patients (8/75) displayed significant reactivity to P0 protein when compared with healthy donor sera (0/45). Four out of the eight sera showed simultaneous reactivity to all P proteins. Breast benign tumor (3/17) and mammary hyperplasia (3/17) patient sera also showed significant reactivity to P proteins, thus suggesting that the occurrence of P protein autoantibodies might reveal mammary cell cycle dysregulation. Patient sera reacting with all P proteins recognized C-22 P0. Anti-P0 autoantibodies did not correlate with prognostic parameters of breast carcinomas. High level expression of C-22 P0 was found in mammary carcinomas compared with normal adjacent epithelium and benign lesions. To determine the antitumor activity of P0 as an immunogen, BALB-neuT transgenic mice displaying age-related breast cancer progression were vaccinated using xenogeneic P0 at the stage of mammary atypical hyperplasia. P0 vaccination significantly delayed the onset of mouse mammary tumors that overexpressed C-22 P0. Sera from P0 vaccinated mice recognized C-22 P0. Evidence for immunity to the P0 protein, its overexpression in carcinomas and its peculiar surface localization on cancer cells, along with its antitumor activity as an immunogen might be relevant for the use of P0 protein in monitoring cancer progression and in planning immunotherapeutic strategies

    Sensitivity study for a remotely piloted microwave-powered sailplane used as a high-altitude observation

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    The sensitivity of several performance characteristics of a proposed design for a microwave-powered, remotely piloted, high-altitude sailplane to changes in independently varied design parameters was investigated. Results were expressed as variations from baseline values of range, final climb altitude and onboard storage of radiated energy. Calculated range decreased with increases in either gross weight or parasite drag coefficient; it also decreased with decreases in lift coefficient, propeller efficiency, or microwave beam density. The sensitivity trends for range and final climb altitude were very similar. The sensitivity trends for stored energy were reversed from those for range, except for decreasing microwave beam density. Some study results for single parameter variations were combined to estimate the effect of the simultaneous variation of several parameters: for two parameters, this appeared to give reasonably accurate results
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