Friedmann-like equations for High Energy Area of Universe

In this paper, evolution of the high energy area of universe, through the scenario of 5 dimensional (5D) universe, has been studied. For this purpose, we solve Einstein equations for 5D metric and 5D perfect fuid to derive Friedmann-like equations. Then we obtain the evolution of scale factor and energy density with respect to both space-like and time-like extra dimensions. We obtain the novel equations for the space-like extra dimension and show that the matter with zero pressure cannot exist in the bulk. Also, for dark energy fuid and vacuum fluid, we have both accelerated expansion and contraction in the bulk.Comment: 9 pages, Accepted to publication in IJTP 26 June 2012. arXiv admin note: substantial text overlap with arXiv:1202.497

First-order formalism for dark energy and dust

This work deals with first-order formalism for dark energy and dust in standard cosmology, for models described by real scalar field in the presence of dust in spatially flat space. The field dynamics may be standard or tachyonic, and we show how the equations of motion can be solved by first-order differential equations. We investigate a model to illustrate how the dustlike matter may affect the cosmic evolution using this framework.Comment: 5 pages, 1 figure; title changed, new author included, discussions extended, references added, version to appear in EPJ

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Immunological properties of gene vaccines delivered by different routes

Gene vaccines represent a new and promising approach to control infectious diseases, inducing a protective immune response in the appropriate host. Several routes and methods of genetic immunization have been shown to induce antibody production as well as T helper (Th) cell and cytotoxic T lymphocyte activation. However, few studies have compared the nature of the immune responses generated by different gene vaccination delivery systems. In the present study we reviewed some aspects of immunity induced by gene immunization and compared the immune responses produced by intramuscular (im) DNA injection to gene gun-mediated DNA transfer into the skin of BALB/c mice. Using a reporter gene coding for ß-galactosidase, we have demonstrated that im injection raised a predominantly Th1 response with mostly IgG2a anti-ßgal produced, while gene gun immunization induced a mixed Th1/Th2 profile with a balanced production of IgG2a and IgG1 subclasses. Distinct types of immune responses were generated by different methods of gene delivery. These findings have important implications for genetic vaccine design. Firstly, a combination between these two systems may create optimal conditions for the induction of a broad-based immune response. Alternatively, a particular gene vaccine delivery method might be used according to the immune response required for host protection. Here, we describe the characteristics of the immune response induced by gene vaccination and the properties of DNA involved in this process

Distribuição do vírus rábico no sistema nervoso central em ruminantes naturalmente infectados

Com o objetivo de identificar a distribuição das lesões do vírus rábico no sistema nervoso central de casos espontâneos de raiva em ruminantes e comparar as técnicas de imunofluorescência direta (IFD), inoculação em camundongos (ICC) e presença de corpúsculos de Negri para o diagnóstico da doença foram analisados materiais proveniente de 48 casos de raiva, incluindo amostras de córtex frontal, temporal, parietal e occipital, hipocampo, tálamo, colículo rostral e caudal, cerebelo, ponte, medula oblonga, núcleo da base e porções da medula cervical, torácica e lombar. De 48 amostras analisadas, todas foram positivas na IFD e na ICC e em 30 (62,5%) foram encontrados corpúsculo de Negri (CN). No entanto, houve diferenças importantes no resultados dos três testes nas diferentes regiões do SNC avaliadas. Nos cortes de córtex cerebral, em 38 bovinos, a presença de corpúsculos de inclusão foi baixa (11%-37%) assim como a positividade para IFD e ICC (60-80%). Pelo contrário, todas as amostras de ponte, tálamo e medula testados foram positivas para IFD e ICC. Em outras regiões do tronco encefálico e também no cerebelo a positividade para ICC e IFD foi de 60% a 96,7%. No cerebelo foi encontrada a maior frequência (88,2%) de corpúsculos de inclusão. Em oito ovinos as provas de ICC e IFD foram positivas em todos os cortes e foram observados corpúsculos de inclusão em três animais. Foram analisados somente dois casos de caprinos encontrando-se corpúsculos de inclusão em um e ambos foram positivos para IFD e ICC. Os resultados obtidos nesse trabalho sugerem que a conduta recomendada pelo Manual Técnico de Controle da Raiva dos Herbívoros (MTCRH) permite o diagnóstico de raiva associando o estudo histológico aos testes de IFD e ICC que incluem cerebelo, tálamo e tronco encefálico que apresentam alta positividade para as provas de IFD e ICC. No entanto, a melhor conduta é a de incluir metade do encéfalo cortado longitudinalmente e amostras de medula. Isto permite examinar por IFD e ICC uma ou mais regiões onde essas provas apresentam maior positividade e, posteriormente, se essas provas fossem negativas, retornar ao material original e examinar outras regiões. Por outro lado, a coleta de amostras dos locais recomendados pela MTCRH, assim com a coleta de metade do encéfalo, podem prejudicar o diagnóstico de outras doenças para o qual é necessário o estudo de todo o encéfalo após a fixação em formaldeído, para constatar a simetria e a distribuição das lesões. Nestes casos, com base nos resultados obtidos neste trabalho, pode ser recomendado para diagnóstico laboratorial de raiva o envio exclusivo de porções da medula cervical, dorsal e lombar, já que as três porções apresentaram 100% de positividade nas provas de IFD e ICC. Além disso, o estudo histológico de todas as porções do cérebro incluídas neste trabalho permitirá complementar o diagnóstico