An analysis of factors and policies relating to use of highly erodible land in West Tennessee for crop production

Off-site effects of soil erosion from cropland on water quality and flooding are of increasing social concern. The objective of reducing off-site damaging effects from soil erosion has gained in prominence relative to maintaining on-site soil productivity. However, there has been limited success of past Federal soil erosion control programs to induce erosion control on the most highly erosive land, especially the conversion of highly eroding cropland to a permanent vegetative cover. Therefore, the purpose of this study was to evaluate factors and policies relating to use of highly erosive land in West Tennessee for crop production. A survey was conducted in Dyer and Fayette Counties in West Tennessee to obtain data for the analyses. The Soil Conservation Service\u27s 1982 National Resource Inventory data reveals that West Tennessee has 438,000 acres of cropland designated by the Soil Conservation Service as Class IV, VI, and VII--land considered unsuitable for crop production. However, the distribution of this marginal cropland in relation to field operating units is not well known. Landowners\u27 farms in Fayette County are analyzed in this respect. The results indicate that at a field level of analysis. Class IV, VI, and VII cropland is intermingled with many lower lapd capability classes. As such, most of this land is in fields where it represents less than half of the acreage. This distribution may create an unwillingness for landowners to voluntarily participate in conservation programs to induce conversion of this type of land to a permanent vegetative cover and would also cause difficulty in administering a regulatory approach to require conversion. A logit regression model was used to evaluate factors which may influence landowners to row-crop Class IV, VI, and VII land. In addition, farmers\u27 estimates of their yields, prices, and variable production expenses for row-crops grown on the highly erosive fields in the study were analyzed to ascertain what level of net returns farmers perceived they were obtaining. Implications for policies to influence conversion of highly erosive land to a permanent vegetative cover were investigated. The Food Security Act of 1985 has a Conservation Reserve Program where farm operators would submit bids for the amount of payment they would accept from the Federal government to convert highly erosive land to a permanent vegetative cover. Hypothetical bids were obtained from the landowners in both Dyer and Fayette Counties and then analyzed. The results from this study indicate that a bidding approach to retire highly erosive cropland is more cost effective from a public policy perspective than traditional uniform offer approaches. Finally, information on owner, farm, and field characteristics was utilized in a regression model to estimate the relationship of these characteristics to landowners\u27 bid levels

Adapting an Online Learning Quality Assurance Framework in a Developing Country Setting: The Case of a HEI in Malawi

Covid-19 prompted many higher education institutions (HEIs), even in developing countries like Malawi, to abruptly shift from their traditional face-to-face mode of delivery to online learning. However, quality issues with online learning remain one of the greatest challenges to acceptance of online learning by many students and stakeholders. This paper presents an action research based study at the Malawi University of Science and Technology, in which an online learning quality assurance framework is adapted to a developed country setting. The adapted framework builds on the Online Learning Consortium (OLC) Quality Scorecard for the Administration of Online Programs. The contextualization and validation of the framework is done using a modified mini-Delphi technique. Validation of the adapted framework identified key issues including financing of online learning, IT infrastructure challenges, lack of faculty training in online teaching and need for proper quality assurance instruments for monitoring online learning

Using green fluorescent malaria parasites to screen for permissive vector mosquitoes

BACKGROUND: The Plasmodium species that infect rodents, particularly Plasmodium berghei and Plasmodium yoelii, are useful to investigate host-parasite interactions. The mosquito species that act as vectors of human plasmodia in South East Asia, Africa and South America show different susceptibilities to infection by rodent Plasmodium species. P. berghei and P. yoelii infect both Anopheles gambiae and Anopheles stephensi, which are found mainly in Africa and Asia, respectively. However, it was reported that P. yoelii can infect the South American mosquito, Anopheles albimanus, while P. berghei cannot. METHODS: P. berghei lines that express the green fluorescent protein were used to screen for mosquitoes that are susceptible to infection by P. berghei. Live mosquitoes were examined and screened for the presence of a fluorescent signal in the abdomen. Infected mosquitoes were then examined by time-lapse microscopy to reveal the dynamic behaviour of sporozoites in haemolymph and extracted salivary glands. RESULTS: A single fluorescent oocyst can be detected in live mosquitoes and P. berghei can infect A. albimanus. As in other mosquitoes, P. berghei sporozoites can float through the haemolymph and invade A. albimanus salivary glands and they are infectious in mice after subcutaneous injection. CONCLUSION: Fluorescent Plasmodium parasites can be used to rapidly screen susceptible mosquitoes. These results open the way to develop a laboratory model in countries where importation of A. gambiae and A. stephensi is not allowed

Imaging malaria sporozoites in the dermis of the mammalian host

The initial phase of malaria infection is the pre-erythrocytic phase, which begins when parasites are injected by the mosquito into the dermis and ends when parasites are released from hepatocytes into the blood. We present here a protocol for the in vivo imaging of GFP-expressing sporozoites in the dermis of rodents, using the combination of a high-speed spinning-disk confocal microscope and a high-speed charge-coupled device (CCD) camera permitting rapid in vivo acquisitions. the steps of this protocol indicate how to infect mice through the bite of infected Anopheles stephensi mosquitoes, record the sporozoites' fate in the mouse ear and to present the data as maximum-fluorescence-intensity projections, time-lapse representations and movie clips. This protocol permits investigating the various aspects of sporozoite behavior in a quantitative manner, such as motility in the matrix, cell traversal, crossing the endothelial barrier of both blood and lymphatic vessels and intravascular gliding. Applied to genetically modified parasites and/or mice, these imaging techniques should be useful for studying the cellular and molecular bases of Plasmodium sporozoite infection in vivo.Inst Pasteur, Unite Biol & Genet Paludisme, F-75724 Paris 15, FranceWeb of Scienc

Cryoelectron tomography reveals periodic material at the inner side of subpellicular microtubules in apicomplexan parasites

Microtubules are dynamic cytoskeletal structures important for cell division, polarity, and motility and are therefore major targets for anticancer and antiparasite drugs. In the invasive forms of apicomplexan parasites, which are highly polarized and often motile cells, exceptionally stable subpellicular microtubules determine the shape of the parasite, and serve as tracks for vesicle transport. We used cryoelectron tomography to image cytoplasmic structures in three dimensions within intact, rapidly frozen Plasmodium sporozoites. This approach revealed microtubule walls that are extended at the luminal side by an additional 3 nm compared to microtubules of mammalian cells. Fourier analysis revealed an 8-nm longitudinal periodicity of the luminal constituent, suggesting the presence of a molecule interacting with tubulin dimers. In silico generation and analysis of microtubule models confirmed this unexpected topology. Microtubules from extracted sporozoites and Toxoplasma gondii tachyzoites showed a similar density distribution, suggesting that the putative protein is conserved among Apicomplexa and serves to stabilize microtubules

Rapid assays and continuous in-situ biosensors for bioprocess monitoring

Fast, accurate, and precise measurements are critical in the biofuels, biochemical, biopharma, and biotechnology industries. Bioprocessing operations require rapid measurement techniques during cultivations to ensure product quality, ensure batch-to-batch consistency, increase product yield, improve process efficiency, and prevent expensive shutdowns. Although continuous sensors exist for dissolved oxygen, pressure, temperature, and pH, organic chemical concentrations must be measured using expensive equipment that can take hours or days to yield results. OptiEnz Sensors provides a biosensor platform for rapid assay or continuous monitoring of organic chemicals. The platform consists of an instrument with an attached sensor probe and replaceable sensor caps with multiple sensor spots. The sensor tips are unique to each chemical to be measured. The platform includes PC-based software for product configuration, display of results in both digital and graphical formats, and data export to process control systems. This technology is available in two platforms: A rapid assay system capable of quickly measuring the analyte concentration in samples and an in-situ probe for continuous, aseptic measurements in a bioreactor. The sensors are accurate, specific, and quantitative. OptiEnz has identified over 50 organic chemicals that can be measured using this technology and has constructed and tested biosensors for 22 of them. Of particular importance to biotech process monitoring are sensors for glucose, ethanol, lactate, glutamate, glutamine, xylose, lactose, glycerol, butanol, and methanol. The rapid assay system is on the market now for glucose and ethanol concentration measurement and a continuous sensor for in-situ glucose concentration monitoring is in customer trial

Changing trends in novel benzodiazepine use within Scottish prisons:detection, quantitation, prevalence, and modes of use

Drug use within prisons is increasingly complex and unpredictable. Benzodiazepines are currently one of the most common drugs detected in individuals leaving Scottish prisons; however, understanding illicit benzodiazepine use within prisons and assessing the potential harm to individuals is challenging due to the lack of available analytical data on the substances circulating. Increasingly, materials, such as paper and clothing, infused with novel benzodiazepines have been identified as a smuggling route into Scottish prisons. Methods were developed for the qualitative and quantitative analysis of benzodiazepines using gas chromatography–mass spectrometry (GC–MS) and applied to 495 seized samples from 11 Scottish prisons, including papers, cards, blotters, powders, tablets, and clothing. Evolution in the benzodiazepines being detected was demonstrated, with etizolam being the most prevalent throughout 2020/2021 following which flubromazepam and bromazolam detections increased. Additionally, significant changes in the smuggling methods and drug formats detected occurred over time following policy changes within prisons. These data represent the first reported widescale etizolam quantitation data and demonstrate high levels of variability across all sample types, most notably within tablets (0.34–2.33 mg per tablet). Additionally, concentration mapping of a whole seized card sample revealed the total concentration of drug present (312.5 mg) and demonstrated variability across the surface of the card (1.16–1.87 mg/cm 2). These data highlight the challenges of consistent dosing for individuals and the high risks of unintentional overdose. Increased understanding of the challenge of such drug smuggling and benzodiazepine use will aid in the development of strategies to reduce supply and mitigate harm.</p

Host cell traversal is important for progression of the malaria parasite through the dermis to the liver

The malaria sporozoite, the parasite stage transmitted by the mosquito, is delivered into the dermis and differentiates in the liver. Motile sporozoites can invade host cells by disrupting their plasma membrane and migrating through them (termed cell traversal), or by forming a parasite-cell junction and settling inside an intracellular vacuole (termed cell infection). Traversal of liver cells, observed for sporozoites in vivo, is thought to activate the sporozoite for infection of a final hepatocyte. Here, using Plasmodium berghei, we show that cell traversal is important in the host dermis for preventing sporozoite destruction by phagocytes and arrest by nonphagocytic cells. We also show that cell infection is a pathway that is masked, rather than activated, by cell traversal. We propose that the cell traversal activity of the sporozoite must be turned on for progression to the liver parenchyma, where it must be switched off for infection of a final hepatocyte.Inst Pasteur, Unite Biol & Genet Paludisme, F-75724 Paris 15, FranceUniversidade Federal de São Paulo, Dept Bioquim, BR-04044020 São Paulo, BrazilUniv Montpellier 2, CNRS, UMR 5539, F-34095 Montpellier 05, FranceMie Univ, Sch Med, Tsu, Mie 5140001, JapanUniversidade Federal de São Paulo, Dept Bioquim, BR-04044020 São Paulo, BrazilWeb of Scienc