Assessing students in community settings: the role of peer evaluation

The assessment of students in community settings faces unique difficulties. Since students are usually posted in small groups in different community settings and since the learning (largely) takes place outside the classroom, assessing student performance becomes an intrinsically complex endeavor. In this article, the proposition is made and tested that peers may be used to accurately assess particular aspects of performance, in particular those which need extensive and close observation. Examples are: Effort displayed while working in a community, quality of the interaction with that community, display of leadership, and subject-matter contributions

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

A comprehensive Software Copy Protection and Digital Rights Management platform

This article proposes a Powerful and Flexible System for Software Copy Protection (SCP) and Digital Rights Management (DRM) based on Public Key Infrastructure (PKI) standards. Software protection is achieved through a multi-phase methodology with both static and dynamic processing of the executable file. The system defeats most of the attacks and cracking techniques and makes sure that the protected software is never in a flat form, with a suitable portion of it always being encrypted during execution. A novel performance-tuning algorithm is proposed to lower the overhead of the protection process to its minimum depending on the software dynamic execution behavior. All system calls to access resources and objects such as files, and input/output devices are intercepted and encapsulated with secure rights management code to enforce the required license model. The system can be integrated with hardware authentication techniques (like dongles), and to Internet based activation and DRM servers over the cloud. The system is flexible to apply any model of licensing including state-based license such as expiration dates and number of trials. The usage of a standard markup language (XrML) to describe the license makes it easier to apply new licensing operations like re-sale and content rental

Poly (acrylonitrile-co-methyl methacrylate) nanoparticles: I. Preparation and characterization

This work concerns the preparation and characterization of poly (acrylonitrile-co-methyl methacrylate) Copolymer, P(AN-co-MMA), nano-particles using precipitation polymerization technique. Potassium per-sulfate redox initiation system was used to perform polymerization process in an alcoholic aqueous system. The impact of different polymerization conditions such as comonomer concentration and ratio, polymerization time, polymerization temperatures, initiator concentration and co-solvent composition on the polymerization yield and particle size was studied. Maximum polymerization yield, 70%, was obtained with MMA:AN (90%:10%) comonomer composition. Particle sizes ranging from 16 nm to 1483 nm were obtained and controlled by variation of polymerization conditions. The co-polymerization process was approved by FT-IR and TGA analysis. The copolymer composition was investigated by nitrogen content analysis. Copolymers with a progressive percentage of PAN show thermal stabilities close to PAN Homopolymer. SEM photographs prove spherical structure of the produced copolymers. The investigated system shows promising future in the preparation of nanoparticles from comonomers without using emulsifiers or dispersive agents

Geophysical assessment of the hydraulic property of the fracture systems around Lake Nasser-Egypt: In sight of polarimetric borehole radar

Hydraulic property of the subsurface structures is a complicated mission. In this work, the polarimetric analysis for the measured dataset applied by the polarimetric borehole radar system in order to delineate the characteristics of subsurface fractures. Two different locations in USA and Egypt were selected to perform our investigation. The first polarimetric dataset has been acquired at Mirror Lake, USA which is well known as a standard site for testing the hydraulic properties of subsurface fractures (Sato et al., 1999). The results show the presence of nine fracture zones in one borehole FSE-1. The hydraulic properties were detected and the subsurface fractures were differentiated into four categories fracture zones after deriving the radar polarimetric analysis of alpha, entropy and anisotropy parameters at 30 MHz frequency. The fracture zones at 24.75, 47.8 and 55.2 m depths have the highest hydraulic transmissivity while the fracture zones at 28.5, 36.15 m have the lowest hydraulic transmissivity. These results show a good consistency with the hydraulic permeability tracer test and the structures exist in the area. Similarly, we used the same technique to characterize the subsurface fracture systems detected by geoelectric and geomagnetic methods around Lake Nasser in Egypt using the previous results of Mirror Lake as a key guide. The results show a great correlation with detected structures prevailed in the sedimentary and basement rocks. These results illustrate an ideal explanation for the prevailed subsurface structures and the recharging of the main Nubian sandstone aquifer from Lake Nasser. Also, these results also show that the northeast fracture zone trends are most probably having the highest hydraulic transmissivity whereas the northwest fracture zones have the lowest one. The integration of surface geophysical measurements with the polarimetric borehole radar and the polarimetric analysis of its datasets introduce better understanding of the recharging mechanism between surface water and the subsurface aquifer and also can be used as clue for identifying the subsurface structures for different areas

Seroprevalence and real-time PCR study of Epstein-Barr virus and the value of screening in pretransplant patients

Objective This study was performed to estimate the prevalence of Epstein-Barr virus immunoglobulin M virus capsid antigen (EBV IgM VCA) among healthy blood donors and to confirm the real risk of transfusion transmission by detection of virus load using PCR quantification. Materials and methods A total of 860 apparently healthy Egyptian blood donors were enrolled and tested for EBV IgM VCA. Quantitative PCR was performed for reactive cases for EBV IgM VCA. Results An overall 38 patients were reactive for EBV IgM VCA, constituting 4.4% of the sample. Reactivity of Epstein-Barr virus did not differ significantly as regards sex distribution, blood grouping, Rh factor positivity, and hemoglobin level, but it was significantly higher among upper Egypt participants than among those from other regions (P = 0.006). There was a very high statistically significant positive correlation between the titer of EBV VCA IgM reactive cases and age in the studied group (P = 0.0001 and r = 0.6). PCR was negative for all of the reactive cases. Conclusion Routine screening for Epstein-Barr virus in blood bags is not economical. Screening is highly recommended only for immunocompromised and pretransplant patients. Viremia is not the role in individuals with EBV IgM positive sera, which in turn changes some concepts in organ transplantation