536 research outputs found

    Herpetofauna From An Urban Pampa Fragment In Southern Brazil: Composition, Structure And Conservation

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    Faunistic inventories regarding natural history of amphibians and reptiles are considered scarce and very little is known about their assemblages in urban areas; the Pampas morphoclimatic domain, also known as Uruguayan Savannah or Southern Grasslands, is also poorly known regarding their faunal composition. Herein, we present a checklist of 16 amphibian and 20 reptile species recorded over a course of four years in the Instituto Federal de Educação, Ciências e Tecnologia, Câmpus Pelotas-Visconde da Graça, in Pelotas, Rio Grande do Sul, Brazil. We also present data on natural history and discuss conservation efforts to be undertaken in the area, in one of the least preserved and known Brazilian morphoclimatic domains, providing insights into urban herpetofaunal diversity patterns and showing the importance of modified areas in its conservation. © 2016 Check List and Authors.12

    Vlp-based vaccines as a suitable technology to target trypanosomatid diseases

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    Funding Information: This research was funded by Global Health and Tropical Medicine (Grant number IHMT UID/multi/04413/2013 and Grant number PTDC/CVT-CVT/28908/2017), Funda??o para Ci?ncia e Tecnologia (FCT), Portugal; Grant GIU18/172 Grupos de Investigaci?n de la UPV/EHU, and Grant from CSIC Programa I-COOP+2020 (ICOOPB20503), Spain.A.M.V.Q., J.W.d.F.O., and C.J.M. thanks to the financial support (PhD scholar-ships) provided by CNPq and CAPES, Brazil. M.S.S. thanks to CNPq for the Research Grant (Bolsa de Produtividade em Pesquisa). We are also grateful to Paulo Fanado and Laysa Ohanna for editing this manuscript. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Research on vaccines against trypanosomatids, a family of protozoa that cause neglected tropical diseases, such as Chagas disease, leishmaniasis, and sleeping sickness, is a current need. Today, according to modern vaccinology, virus-like particle (VLP) technology is involved in many vaccines, including those undergoing studies related to COVID-19. The potential use of VLPs as vaccine adjuvants opens an opportunity for the use of protozoan antigens for the development of vaccines against diseases caused by Trypanosoma cruzi, Leishmania spp., and Trypanosoma brucei. In this context, it is important to consider the evasion mechanisms of these protozoa in the host and the antigens involved in the mechanisms of the parasite–host interaction. Thus, the immunostimulatory properties of VLPs can be part of an important strategy for the development and evaluation of new vaccines. This work aims to highlight the potential of VLPs as vaccine adjuvants for the development of immunity in complex diseases, specifically in the context of tropical diseases caused by trypanosomatids.publishersversionpublishe

    Limited risk of Zika virus transmission by five Aedes albopictus populations from Spain

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    Background: Aedes albopictus, the Asian tiger mosquito, is an exotic invasive species in Europe. It has substantial public health relevance due to its potential role in transmitting several human pathogens. Out of the European countries, Spain has one of the highest risk levels of autochthonous arbovirus transmission due to both the high density of Ae. albopictus and the extensive tourist influx from vector-endemic areas. This study aims to investigate the susceptibility of five Ae. albopictus populations from mainland Spain and the Balearic Islands to a Brazilian Zika virus (ZIKV) strain. Methods: The F1 generation of each Ae. albopictus population was orally challenged with a ZIKV-infected blood meal (1.8 × 10 PFU/ml). At 7 and 14 days post-infection (dpi), mosquito bodies (thorax and abdomen) and heads were individually analysed through RT-qPCR to determine the infection rate (IR) and dissemination rate (DR), respectively. The saliva of infected mosquitoes was inoculated in Vero cells and the transmission rate was assessed by plaque assay or RT-qPCR on ∼33 individuals per population. Results: The IR and DR ranged between 12-88%, and 0-60%, respectively, suggesting that ZIKV is capable of crossing the midgut barrier. Remarkably, no infectious viral particle was found in saliva samples, indicating a low ability of ZIKV to overcome the salivary gland barrier. A subsequent assay revealed that a second non-infective blood meal 48 h after ZIKV exposure did not influence Ae. albopictus vector competence. Conclusions: The oral experimental ZIKV infections performed here indicate that Ae. albopictus from Spain become infected and disseminate the virus through the body but has a limited ability to transmit the Brazilian ZIKV strain through biting. Therefore, the results suggest a limited risk of autochthonous ZIKV transmission in Spain by Ae. albopictus

    The Ideal Climate Latitude: Orbit and Axial Precession Influence in Ancient Migration

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    It is widely understood that ice ages are periods when ancient humans constantly migrated mainly due to changes in climate. This article proposes that the combination of the precession of the Earth’s axis and the eccentricity of the Earth’s orbit around the world creates an ideal climate latitude, which has major impacts on migration patterns. During the ice ages the orbit of the Earth’s axis is considerably elliptic and the difference in distance from the Earth to the Sun during the perihelion and aphelion reached as much as 12%, which resulted in a difference of irradiation of 27%. The precession of the Earth’s axis changes the latitude where the Sun is perpendicular to the Sun during the aphelion and perihelion in a cycle of 19 to 26 thousand years. Ancient civilizations prevailed or purposely migrated to latitudes with the most favorable climate, where the aphelion happened during the summer and the perihelion happened during the winter. This article shows that major ancient migration patterns follow with some precision this ideal climate latitude

    Hydraulic isothermal pressure reduction turbine: An efficient and low-cost electricity generation source

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    There is currently a large amount of energy being wasted on pressure reduction valves across the world. This paper argues that this energy could be harnessed with isothermal depressurization by applying a hydraulic isothermal pressure reduction turbine. The hydraulic isothermal pressure reduction turbine consists of two tanks filled with water or an organic liquid. The pressurized gas enters the tank, displacing the liquid, which flows through a turbine, generating electricity. The proposed system has efficiencies surrounding 90%, which is higher than usual pressure reduction turbines. The estimated cost for the proposed technology is 1300 USD/kW. The proposed technology could be feasible to harness the potential for electricity generation wasted in pressure reduction valves. The need for this technology will increase significantly in a future hydrogen-based economy, given the low volumetric density of hydrogen and the significant energy losses when compressing and decompressing hydrogen

    Solid air hydrogen liquefaction, the missing link of the hydrogen economy

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    The most challenging aspect of developing a green hydrogen economy is long-distance oceanic transportation. Hydrogen liquefaction is a transportation alternative. However, the cost and energy consumption for liquefaction is currently prohibitively high, creating a major barrier to hydrogen supply chains. This paper proposes using solid nitrogen or oxygen as a medium for recycling cold energy across the hydrogen liquefaction supply chain. When a liquid hydrogen (LH2) carrier reaches its destination, the regasification process of the hydrogen produces solid nitrogen or oxygen. The solid nitrogen or oxygen is then transported in the LH2 carrier back to the hydrogen liquefaction facility and used to reduce the energy consumption cooling gaseous hydrogen. As a result, the energy required to liquefy hydrogen can be reduced by 25.4% using N2 and 27.3% using O2. Solid air hydrogen liquefaction (SAHL) can be the missing link for implementing a global hydrogen economy

    Soil cover plants on water erosion control in the South of Minas Gerais

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    Water erosion is responsible for soil, water, carbon and nutrient losses, turning into the most important type of degradation of Brazilian soils. This study aimed to evaluate the influence of three cover plants under two tillage systems on water erosion control in an Argisol at south of Minas Gerais state, Brazil. The cover plants utilized in the study were pigeon pea, jack bean and millet, under contour seeding and downslope tillage. Experimental plots of 4 x 12 m, with 9% slope, under natural rainfall were used for the quantification of losses of soil, water, nutrients, and organic matter. One experimental plot was kept without plant cover (reference). Higher erosivity was observed in December and January, although a great quantity of erosive rainfall was detected during the whole raining period. Contour seeding provided a greater reduction of water erosion than downslope tillage, as expected. The jack bean under contour seeding revealed the lowest values of soil, water, nutrients and organic matter losses

    Supersymmetric Regularization, Two-Loop QCD Amplitudes and Coupling Shifts

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    We present a definition of the four-dimensional helicity (FDH) regularization scheme valid for two or more loops. This scheme was previously defined and utilized at one loop. It amounts to a variation on the standard 't Hooft-Veltman scheme and is designed to be compatible with the use of helicity states for "observed" particles. It is similar to dimensional reduction in that it maintains an equal number of bosonic and fermionic states, as required for preserving supersymmetry. Supersymmetry Ward identities relate different helicity amplitudes in supersymmetric theories. As a check that the FDH scheme preserves supersymmetry, at least through two loops, we explicitly verify a number of these identities for gluon-gluon scattering (gg to gg) in supersymmetric QCD. These results also cross-check recent non-trivial two-loop calculations in ordinary QCD. Finally, we compute the two-loop shift between the FDH coupling and the standard MS-bar coupling, alpha_s. The FDH shift is identical to the one for dimensional reduction. The two-loop coupling shifts are then used to obtain the three-loop QCD beta function in the FDH and dimensional reduction schemes.Comment: 44 pages, minor corrections and clarifications include
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