Experimental and Numerical Investigation of Post-Flutter Limit Cycle Oscillations on a Cantilevered Flat Plate

Futuristic aircraft designs and novel aircraft such as High Altitude Long Endurance (HALE) involve a higher level of structural flexibility than in conventional aircraft. Even at present, the trends in the aviation industry are to increase wing length (to reduce induced drag) and maxi- mize use of composites, which lead to increased structural flexibility. This necessitates a rethink of conventional (linear) aeroelastic analysis, since the increased flexibility results in coupling between the flight dynamic and aeroelastic dynamics, and consequently, limit-cycle oscillations of the structure. In this paper, a new three-dimensional low-order model for unsteady aerody- namics that accounts for large oscillation amplitudes and nonplanar wakes is developed. An experiment with a cantilevered flat plate at low Reynolds number is set up and used to validate the low-order model, as well as to study post-flutter limit-cycle oscillations. Results from the low-order model are promising, but show that aerodynamic nonlinearities such as flow sepa- ration and leading-edge vortex shedding must also be modeled in order to predict all possible limit-cycle oscillations of the aeroelastic system

Industrial Investment in an 'Export' Economy: the Brazilian Experience before 1914

Under what conditions does an economy specialised in primary product exports become industrialised? More specifically, what induces capital to move into activities geared to the internal market, rather than the traditional export sector, and where does this capital come from? The Brazilian experience since the late nineteenth century is clearly relevant in connection with those questions: it represents - distortions and inequalities apart - an accomplished transformation of a typical export-based economy into one with a relatively high level of diversification. This paper brings some new evidence on the first steps of that process, in the period before the First World War. This evidence, it will be argued, brings into question some accepted notions on the early development of manufacturing production in Brazil, especially as concerns the role of tariff protection, and the relations between the new sector and the old export-oriented activities

Developing a Feline Immunodeficiency Virus Subtype B Vaccine Prototype Using a Recombinant MVA Vector

The feline immunodeficiency virus (FIV) is a retrovirus with global impact and distribution, affecting both domestic and wild cats. This virus can cause severe and progressive immunosuppression culminating in the death of felids. Since the discovery of FIV, only one vaccine has been commercially available. This vaccine has proven efficiency against FIV subtypes A and D, whereas subtype B (FIV-B), found in multiple continents, is not currently preventable by vaccination. We, therefore, developed and evaluated a vaccine prototype against FIV-B using the recombinant viral vector modified vaccinia virus Ankara (MVA) expressing the variable region V1–V3 of the FIV-B envelope protein. We conducted preclinical tests in immunized mice (C57BL/6) using a prime-boost protocol with a 21 day interval and evaluated cellular and humoral responses as well the vaccine viability after lyophilization and storage. The animals immunized with the recombinant MVA/FIV virus developed specific splenocyte proliferation when stimulated with designed peptides. We also detected cellular and humoral immunity activation with IFN-y and antibody production. The data obtained in this study support further development of this immunogen and testing in cats

Influence of previous Zika virus infection on acute dengue episode.

BackgroundThe co-circulation of flaviviruses in tropical regions has led to the hypothesis that immunity generated by a previous dengue infection could promote severe disease outcomes in subsequent infections by heterologous serotypes. This study investigated the influence of antibodies generated by previous Zika infection on the clinical outcomes of dengue infection.Methodology/principal findingsWe enrolled 1,043 laboratory confirmed dengue patients and investigated their prior infection to Zika or dengue. Severe forms of dengue disease were more frequent in patients with previous Zika infection, but not in those previously exposed to dengue.Conclusions/significanceOur findings suggest that previous Zika infection may represent a risk factor for subsequent severe dengue disease, but we did not find evidence of antibody-dependent enhancement (higher viral titer or pro-inflammatory cytokine overexpression) contributing to exacerbation of the subsequent dengue infection

Screening of reactive peptides using monoclonal antibodies.

(A) Heatmap matrix of peptides assessed with monoclonal specific antibodies against ZIKV or DENV in an indirect IgG ELISA platform. Highest scores were selected for soluble synthesis. Peptide ZV-53 was not stable in soluble form and excluded from analysis. (B) IgG pepELISA for validation of soluble peptides. Serum samples from patients validated with PRNT were evaluated on plates with DV-15, DV-20, ZV-54, and ZV-107.</p

Flow of sample selection for dengue-suspected cases with up to 7 days of symptoms onset.

Flow of sample selection for dengue-suspected cases with up to 7 days of symptoms onset.</p

Codebook.

BackgroundThe co-circulation of flaviviruses in tropical regions has led to the hypothesis that immunity generated by a previous dengue infection could promote severe disease outcomes in subsequent infections by heterologous serotypes. This study investigated the influence of antibodies generated by previous Zika infection on the clinical outcomes of dengue infection.Methodology/Principal findingsWe enrolled 1,043 laboratory confirmed dengue patients and investigated their prior infection to Zika or dengue. Severe forms of dengue disease were more frequent in patients with previous Zika infection, but not in those previously exposed to dengue.Conclusions/SignificanceOur findings suggest that previous Zika infection may represent a risk factor for subsequent severe dengue disease, but we did not find evidence of antibody-dependent enhancement (higher viral titer or pro-inflammatory cytokine overexpression) contributing to exacerbation of the subsequent dengue infection.</div

Distribution of dengue-confirmed cases in São José do Rio Preto, São Paulo State, during 2019 epidemic, according to months and epidemiological weeks.

Distribution of dengue-confirmed cases in São José do Rio Preto, São Paulo State, during 2019 epidemic, according to months and epidemiological weeks.</p