42 research outputs found

    The acoustical design of the new lecture auditorium, Faculty of Law, Ain Shams University

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    AbstractThis work represents the main acoustical design phases for the new lecture auditorium in the Faculty of Law, Ain Shams University, Cairo/Egypt. The work also discusses some of the architectural details that were used and have a direct effect on the acoustical environment inside the auditorium. The work compares finally among field measurements (that were recorded after the construction in the unoccupied auditorium), the values expected during the acoustic design phase (utilizing ODEON ver. 4.2, assuming the occupied case), and the optimum values for speech intelligibility indicators that were considered in this work (T20, D50, STI, LAeq, and the background noise). Field measurements that were recorded utilizing MLSSA system showed that the finishing materials used successfully fulfilled a good level of speech intelligibility in the auditorium. The estimated reverberation timeT20-EOC for the occupied room (based on the measured unoccupiedT20-M) was close to the optimum especially in mid and high frequency bands. The measured D50 (unoccupied) was found to be within its acceptable range. The measured STI value (unoccupied) was “Fair, 0.49”. The measurements of LAeq indicated the uniformity of the acoustical field in the room. The noticed problem was a relatively high background noise (NC-40) due to the utilization of natural ventilation which directly contradicts the principles of room isolation

    Integrated Formation Evaluation Study in Cliff Head Field, Northern Perth Basin, Western Australia

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    A new technique was implemented to unlock the reservoir characterisation in complex reservoirs. Integration between the conventional density log and the NMR free fluid index has been carried out, through which a high-resolution electrofacies have been classified using a new technique, named the Equivalent Flow Zone Indicator (EFZI). Further, the permeability and water saturation were calculated through new workflows, both are EFZI dependent, with which a high-resolution parameterisation could be achieved for highly complicated reservoirs

    Truffle and truffle-like fungi from continental Africa

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    Africa is a diverse continent composed of many different terrestrial biomes, from the largest nonpolar desert in the world to equatorial forests and Southern African Fynbos. Biodiversity within the continent is high but much remains to be discovered. Sightings of hypogeous fruiting bodies of mycorrhizal fungi (truffles and truffle-like fungi) have been recorded from the most northern countries of the continent to the most southern countries; they have been widely collected for culinary and medicinal purposes. In this review, we describe the most prominent species of mycorrhizal fungi forming hypogeal fruiting bodies, across six genera. The most ubiquitous of these are the “desert truffle” species and the most common genus of plants with which they associate are those of the genus Helianthemum. We also describe the key species of truffle and truffle-like fungi in continental Africa. Where information exists, we describe the ecology, medicinal properties, and ethnomycology of the identified fungi

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

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    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

    Acoustic improvement on two lecture auditoria: Simulation and experiment

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    Based on the commonly used indicators for speech intelligibility, this work acoustically evaluates the two largest auditoria in the Faculty of Engineering, Helwan University, Cairo, Egypt, using experimental and digital simulation techniques. Design treatments were also suggested to improve the acoustic performance of the auditoria, where the impact of these treatments was checked using the simulation as well. The models that were analysed using the CATT software were first validated utilizing the results of the field work in the unoccupied rooms. The results showed that the acoustic quality of the two auditoria are far from the optimal conditions due to their improper acoustic characteristics and the high noise levels as well. The results of improvement proposals showed that altering the ceiling shape and adding efficient absorptive materials to the rear surfaces successfully reduced the excessive reverberation time to the optimal values, increased the early reflections and eliminated the shadow zones. In addition, decreasing the noise levels by 20 dB due to improving the window insulation noticeably improved the speech intelligibility at all receivers

    Remarks on the Surface Area and Equality Conditions in Regular Forms. Part I: Triangular Prisms

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    The Optimal Reverberation for Masjids: A Subjective Assessment for Worshippers’ Demands

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    This study investigates the optimal reverberation time in masjids (mosques) from worshippers' viewpoint for the two modes of performance: recitation and sermon/speech. It also examines the effect of both age and gender on worshippers' preferences. To this end, specially convolved five audio clips (five acoustic setups) for each mode were created and uploaded to Google Drive. More than 300, Arabic-speaking participants, males, and females of different ages, listened to these clips. The participants judged the quality (Q, or appropriateness) of these audio clips for listening either to the recitation (QR) or speech (QS) on a unipolar discrete five-grade scale via a questionnaire that was created on Google Forms. Results indicated that both QR and QS are functions of gender and age. Overall, younger worshippers preferred higher reverberation and vice versa, while gender significantly affected the perception of the desirable reverberation for both recitation and speech. Females tended to the shorter reverberant environment (1.38 s for recitation mode, 0.75 s for speech mode, in the mid-frequency range) than males who preferred longer reverberation for recitation in particular (1.77 s)

    Acoustic improvement on two lecture auditoria: Simulation and experiment

    No full text
    Based on the commonly used indicators for speech intelligibility, this work acoustically evaluates the two largest auditoria in the Faculty of Engineering, Helwan University, Cairo, Egypt, using experimental and digital simulation techniques. Design treatments were also suggested to improve the acoustic performance of the auditoria, where the impact of these treatments was checked using the simulation as well. The models that were analysed using the CATT software were first validated utilizing the results of the field work in the unoccupied rooms. The results showed that the acoustic quality of the two auditoria are far from the optimal conditions due to their improper acoustic characteristics and the high noise levels as well. The results of improvement proposals showed that altering the ceiling shape and adding efficient absorptive materials to the rear surfaces successfully reduced the excessive reverberation time to the optimal values, increased the early reflections and eliminated the shadow zones. In addition, decreasing the noise levels by 20 dB due to improving the window insulation noticeably improved the speech intelligibility at all receivers
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