Ethane steam reforming over a platinum/alumina catalyst: effect of sulphur poisoning

In this study we have examined the adsorption of hydrogen sulfide and methanethiol over platinum catalysts and examined the effect of these poisons on the steam reforming of ethane. Adsorption of hydrogen sulfide was measured at 293 and 873 K. At 873 K the adsorbed state of hydrogen sulfide in the presence of hydrogen was SH rather than S, even though the Pt:S ratio was unity. The effect of 11.2 ppm hydrogen sulfide or methanethiol on the steam reforming of ethane was studied at 873 K and 20 barg. Both poisons deactivated the catalyst over a number of hours, but methanethiol was found to be more deleterious, reducing the conversion by almost an order of magnitude, possibly due to the co-deposition of sulfur and carbon. Changes in the selectivity revealed that the effect of sulfur was not uniform on the reactions occurring, with the production of methane reduced proportionally more than the other products, due to the surface sensitivity of the hydrogenolysis and methanation reactions. The water-gas shift reaction was affected to a lesser extent. No regeneration was observed when hydrogen sulfide was removed from the feedstream in agreement with adsorption studies. A slight regeneration was observed when methanethiol was removed from the feed, but this was believed to be due to the removal of carbon rather than sulfur. The overall effect of sulfur poisoning was to reduce activity and enhance hydrogen selectivity

A Framework for Realistic 3D Tele-Immersion

Meeting, socializing and conversing online with a group of people using teleconferencing systems is still quite different from the experience of meeting face to face. We are abruptly aware that we are online and that the people we are engaging with are not in close proximity. Analogous to how talking on the telephone does not replicate the experience of talking in person. Several causes for these differences have been identied and we propose inspiring and innovative solutions to these hurdles in attempt to provide a more realistic, believable and engaging online conversational experience. We present the distributed and scalable framework REVERIE that provides a balanced mix of these solutions. Applications build on top of the REVERIE framework will be able to provide interactive, immersive, photo-realistic experiences to a multitude of users that for them will feel much more similar to having face to face meetings than the experience offered by conventional teleconferencing systems

Financial market development, global financial crisis and economic growth : evidence from developing nations

Emerging and frontier markets in Africa have witnessed various economic and financial reforms aimed at integrating the domestic markets into the global financial market to attract investment. Whether these reforms promote high economic growth remains inconclusive. The paper applies the pooled mean group estimation technique to empirically re-investigate the link between financial market development, global financial crisis, and economic growth in selected African economies. The results strongly support our hypotheses that stock market and banking sector development promotes economic growth in the selected countries. Moreover, financial crisis reduce the positive effects of both the stock market and banking sector developments on economic growth. The study suggests that both the banking sector and stock market are important to deliver the long-run economic growth that the African region desired. Moreover, effort should be made to enact policy measures that would ensure development of the stock market which has received inadequate attention.info:eu-repo/semantics/publishedVersio

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

Seroprevalence of foot and mouth disease in traditionally managed cattle in East and West Hararghe zones, Ethiopia

Serological evidence of exposure to foot and mouth disease virus (FMDV) was assessed in traditionally managed cattle in 21 districts of East and West Hararghe zones in Oromiya State, Ethiopia, through a cross-sectional survey conducted between November 2008 and March 2009. Sera collected from 504 cattle were tested for antibodies against FMDV using a commercial ELISA. Antibodies to FMDV were detected at an overall prevalence rate of 11.6% [95% confidence interval (95CI): 8.6–14.5%]. In West Hararghe the seroprevalence was significantly (p < 0.05) higher (25.7%; 95CI: 19.6– 31.9%) than in East Hararghe (1.4%; 95CI: 0.0–3.3%). Location [odds ratio (OR) 0.87], altitude (OR 0.62), and age (OR 1.12) were found to be significant infection risk factors. Cattle sampled in the lowlands had a significantly (p < 0.05) higher FMDV seroprevalence (36.2%) than those in the highlands (3.4%). Furthermore, cattle in districts dominated by agropastoralists and those closer to the pastoral and agropastoral communities of Somali (6.4%) and Afar (21.3–46.1%) regional states showed higher seropositivity. The study found that FMDV circulated in the areas at a relatively low frequency, which may however increase because of unrestricted movement of animals within the region and across borders. Owing to the extensive livestock production system and difficulties in controlling livestock movement, alternative control strategies involving targeted surveillance, enhanced early disease recognition and reporting, and prophylactic vaccination are suggested as feasible options of FMD control in the areas. Further studies are also suggested to ascertain the volume and pattern of livestock movement and characterize the circulating FMDV serotypes in the areas

Foot and mouth disease in selected districts of western Ethiopia: seroprevalence and associated risk factors

A study was conducted in western Ethiopia in two districts of Oromia state and four districts of Beneshangul Gumuz state to determine the seroprevalence of foot and mouth disease and the associated risk factors, using multistage random sampling. A 3ABC blocking enzyme-linked immunosorbent assay was used to measure antibody against the non-structural protein of foot and mouth disease virusto differentiate between vaccinated and infected animals. Atotal of 1,144 sera from 181 herds were collected and examined. The overall seroprevalence at animal level and herd level was 9% (95% C17.2-10.6) and 38.1% (95% CI 29.1-47.1), respectively. Statistically significant differences (p < 0.05) were recorded among different species, with 13%, 5% and 3% seropositivity in cattle, sheep and goats, respectively. Statistically significant differences (p < 0.05) in herd seroprevalence were observed among districts, with 52%, 50%, 50%, 44%, 21% and 11% in Gidami, Begi, Tongo, Bambasi, Mange and Asosa districts, respectively. In univariable and multivariable logistic regression, the variables that had a positive relationship with seroprevalence at herd level (p < 0.05) were herd size, contact of livestock with ungulate wildlife, and contact of animals with animals/herds of a different peasant association. Univariable and multivariable logistic regression analysis indicated that, at the animal level, age and species had a statistically significant association (p < 0.05) with seropositivity. In conclusion, herd size, contact of livestock with ungulate wildlife, contact between herds from different peasant associations, and the age and species of the animals were the main risk factors for virus circulation in the study area