A semi-analytical solution for transient streaming potentialsassociated with confined aquifer pumping tests

We consider the transient streaming potential response due to pumping from a confined aquifer through a fully penetrating line sink. Confined aquifer flow is assumed to occur without fluid leakage from the confining units. However, since confining units are typically clayey, and hence more electrically conductive than the aquifer, they are treated as non-insulating in our three-layer conceptual model. We develop a semi-analytical solution for the transient streaming potentials response of the aquifer and the confining units to pumping of the aquifer. The solution is fitted to field measurements of streaming potentials associated with an aquifer test performed at a site located near Montalto Uffugo, in the region of Calabria in Southern Italy. This yields an average hydraulic conductivity that compares well to the estimate obtained using only hydraulic head data. Specific storage is estimated with greater estimation uncertainty than hydraulic conductivity and is significantly smaller than that estimated from hydraulic head data. This indicates that specific storage may be a more difficult parameter to estimate from streaming potential data. The mismatch may also be due to the fact that only recovery streaming potential data were used here whereas head data for both production and recovery were used. The estimate from head data may also constitute an upper bound since head data were not corrected for pumping and observation wellbore storage. Estimated values of the electrical conductivities of the confining units compare well to those estimated using electrical resistivity tomography. Our work indicates that, where observation wells are unavailable to provide more direct estimates, streaming potential data collected at land surface may, in principle, be used to provide preliminary estimates of aquifer hydraulic conductivity and specific storage, where the latter is estimated with greater uncertainty than the former

Comparing various multi-component global heliosphere models

Modeling of the global heliosphere seeks to investigate the interaction of the solar wind with the partially ionized local interstellar medium. Models that treat neutral hydrogen self-consistently and in great detail, together with the plasma, but that neglect magnetic fields, constitute a sub-category within global heliospheric models. There are several different modeling strategies used for this sub-category in the literature. Differences and commonalities in the modeling results from different strategies are pointed out. Plasma-only models and fully self-consistent models from four research groups, for which the neutral species is modeled with either one, three, or four fluids, or else kinetically, are run with the same boundary parameters and equations. They are compared to each other with respect to the locations of key heliospheric boundary locations and with respect to the neutral hydrogen content throughout the heliosphere. In many respects, the models' predictions are similar. In particular, the locations of the termination shock agree to within 7% in the nose direction and to within 14% in the downwind direction. The nose locations of the heliopause agree to within 5%. The filtration of neutral hydrogen from the interstellar medium into the inner heliosphere, however, is model dependent, as are other neutral results including the hydrogen wall. These differences are closely linked to the strength of the interstellar bow shock. The comparison also underlines that it is critical to include neutral hydrogen into global heliospheric models.Comment: 10 pages, 4 figures, submitted to a special section at A&A of an ISSI team "Determination of the physical Hydrogen parameters of the LIC from within the Heliosphere

Multicriteria Risk Ranking of Zoonotic Diseases in a Developing Country: A Case Study of Zambia

The integration of a multicriteria decision analysis approach, including techniques such as the Analytic Hierarchy Process (AHP) and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), has yielded valuable insights in the realm of zoonotic disease risk assessment. This analytical framework draws from the OIE-supported manual, utilizing impact assessments, transmission pathways, and categorizations as provided by the OIE itself. Moreover, the consideration of specific zoonotic disease scenarios tailored to individual countries enhances the contextual relevance of the analysis. Through this approach, the ranking of zoonotic diseases is systematically established, offering a comprehensive evaluation of their potential impacts and risks. This methodology encompasses pivotal criteria, including prevalence, economic impact, health impact, transmission pathways, and healthcare capacity, collectively offering a holistic perspective that mirrors the intricate nature of zoonotic diseases. The resultant rankings, derived from both ECDC and OIE data, illuminate diseases that harbor significant threats to both human and animal populations. This ranking fosters the identification of diseases with potential for rapid spread and substantial impact, guiding resource allocation towards prevention, control, and mitigation strategies. The alignment between ECDC and OIE rankings underscores the robustness of the applied methodology, with Plague and Zoonotic TB consistently emerging as high-ranking diseases, reinforcing their acknowledged significance. A consolidated ranking, amalgamating data from both sources, provides an insightful overview of potential risks linked to various zoonotic diseases. Plague, Zoonotic TB, Brucellosis, Trypanosomiasis, and Rabies consistently occupy top positions, presenting a valuable instrument for policymakers, public health officials, and stakeholders in prioritizing resource allocation and intervention strategies. The implementation of a multicriteria decision analysis approach, integrating AHP and TOPSIS methodologies, underpins the generation of informed rankings for Zambian zoonotic diseases. The intricate interplay of criteria like prevalence, economic impact, health impact, transmission pathways, and healthcare capacity forms a comprehensive framework for evaluating the potential risks of diverse diseases. The ensuing ranking, led by Plague and succeeded by Anthrax, Rabies, and others, mirrors their collective risk scores calculated via the adopted methodology. This approach empowers strategic decision-making by pinpointing diseases with heightened potential for adverse impacts on both human and animal populations. The rankings serve as invaluable aids in directing resources, devising strategic interventions, and formulating targeted measures for prevention and control. However, acknowledgment of the dynamic disease landscape and the imperative of adaptive strategies underscores the ongoing importance of monitoring and managing zoonotic diseases effectively in Zambia. By amalgamating data from authoritative sources and embracing a systematic, evidence-based approach, this study accentuates the necessity of addressing zoonotic diseases with a holistic lens, fostering proactive perspectives that augment public health and avert future outbreaks

Characterization of Mycobacterium bovis from Humans and Cattle in Namwala District, Zambia

Tuberculosis remains a major public health problem in Zambia. While human to human transmission of Mycobacterium tuberculosis is of major importance in driving the tuberculosis epidemic, the impact of Mycobacterium bovis transmission from infected cattle is largely unknown. This cross-sectional study aimed at molecular characterization of M. bovis in humans and cattle. A total of 100 human sputum samples and 67 bovine tissues were collected and analyzed for the presence of mycobacteria. Of 65 human samples that harbored acid fast bacteria (AFB), 55 isolates were obtained of which 34 were identified as M. tuberculosis and 2 as M. bovis. AFB-positive bovine samples (n=67) yielded 47 mycobacterial isolates among which 25 were identified as M. bovis and no M. tuberculosis was found. Among the M. bovis isolates, spoligotyping revealed a high homogeneity in genotypes circulating in Namwala district. Human and cattle isolates shared identical MIRU-VNTR genotypes, suggesting that transmission between the two hosts may occur. Therefore, this study has documented zoonotic TB in human patients in Namwala district of Zambia. However, further molecular epidemiological studies in the study area are recommended

Neutral H density at the termination shock: a consolidation of recent results

We discuss a consolidation of determinations of the density of neutral interstellar H at the nose of the termination shock carried out with the use of various data sets, techniques, and modeling approaches. In particular, we focus on the determination of this density based on observations of H pickup ions on Ulysses during its aphelion passage through the ecliptic plane. We discuss in greater detail a novel method of determination of the density from these measurements and review the results from its application to actual data. The H density at TS derived from this analysis is equal to 0.087 \pm 0.022 cm-3, and when all relevant determinations are taken into account, the consolidated density is obtained at 0.09 \pm 0.022 cm-3. The density of H in CHISM based on literature values of filtration factor is then calculated at 0.16 \pm 0.04 cm-3.Comment: Submitted to Space Science Review

Unconfined Aquifer Flow Theory - from Dupuit to present

Analytic and semi-analytic solution are often used by researchers and practicioners to estimate aquifer parameters from unconfined aquifer pumping tests. The non-linearities associated with unconfined (i.e., water table) aquifer tests makes their analysis more complex than confined tests. Although analytical solutions for unconfined flow began in the mid-1800s with Dupuit, Thiem was possibly the first to use them to estimate aquifer parameters from pumping tests in the early 1900s. In the 1950s, Boulton developed the first transient well test solution specialized to unconfined flow. By the 1970s Neuman had developed solutions considering both primary transient storage mechanisms (confined storage and delayed yield) without non-physical fitting parameters. In the last decade, research into developing unconfined aquifer test solutions has mostly focused on explicitly coupling the aquifer with the linearized vadose zone. Despite the many advanced solution methods available, there still exists a need for realism to accurately simulate real-world aquifer tests

First COVID-19 Case in Zambia - Comparative phylogenomic analyses of SARS-CoV-2 detected in African countries

Since its first discovery in December 2019 in Wuhan, China, COVID-19, caused by the novel coronavirus SARS-CoV-2, has spread rapidly worldwide. Whilst African countries were relatively spared initially, the initial low incidence of COVID-19 cases was not sustained for long due to continuing travel links between China, Europe and Africa.. In preparation, Zambia had applied a multisectoral national epidemic disease surveillance and response system resulting in the identification of the first case within 48 hours of the individual entering the country by air travel from a trip to France. Contact tracing showed that SARS-CoV-2 infection was contained within the patient's household, with no further spread to attending health care workers or community members. Phylogenomic analysis of the patient's SARS-CoV-2 strain showed it belonged to lineage B.1.1., sharing the last common ancestor with SARS-CoV-2 strains recovered from South Africa. At the African continental level, our analysis showed that lineage B.1 and B.1.1 lineages appear to be predominant in Africa. Whole genome sequence analysis should be part of all surveillance and case detection activities in order to monitor the origin and evolution of SARS-CoV-2 lineages across Africa

Molecular epidemiology, drug susceptibility and economic aspects of tuberculosis in mubende district, Uganda

<div><p>Background</p><p>Tuberculosis (TB) remains a global public health problem whose effects have major impact in developing countries like Uganda. This study aimed at investigating genotypic characteristics and drug resistance profiles of <i>Mycobacterium tuberculosis</i> isolated from suspected TB patients. Furthermore, risk factors and economic burdens that could affect the current control strategies were studied.</p><p>Methods</p><p>TB suspected patients were examined in a cross-sectional study at the Mubende regional referral hospital between February and July 2011. A questionnaire was administered to each patient to obtain information associated with TB prevalence. Isolates of <i>M. tuberculosis</i> recovered during sampling were examined for drug resistance to first line anti-TB drugs using the BACTEC-MGIT960^TMsystem. All isolates were further characterized using deletion analysis, spoligotyping and MIRU-VNTR analysis. Data were analyzed using different software; MIRU-VNTR <i>plus</i>, SITVITWEB, BioNumerics and multivariable regression models.</p><p>Results</p><p><i>M. tuberculosis</i> was isolated from 74 out of 344 patients, 48 of these were co-infected with HIV. Results from the questionnaire showed that previously treated TB, co-infection with HIV, cigarette smoking, and overcrowding were risk factors associated with TB, while high medical related transport bills were identified as an economic burden. Out of the 67 isolates that gave interpretable results, 23 different spoligopatterns were detected, nine of which were novel patterns. T2 with the sub types Uganda-I and Uganda-II was the most predominant lineage detected. Antibiotic resistance was detected in 19% and multidrug resistance was detected in 3% of the isolates.</p><p>Conclusion</p><p>The study detected <i>M. tuberculosis</i> from 21% of examined TB patients, 62% of whom were also HIV positive. There is a heterogeneous pool of genotypes that circulate in this area, with the T2 lineage being the most predominant. High medical related transport bills and drug resistance could undermine the usefulness of the current TB strategic interventions.</p></div

Whole Genome Sequence Analysis Reveals Lower Diversity and Frequency of Acquired Antimicrobial Resistance (AMR) Genes in E. coli From Dairy Herds Compared With Human Isolates From the Same Region of Central Zambia

Antibiotic treatment of sick dairy cattle is critical for the sustainability of this production system which is vital for food security and societal prosperity in many low and middle-income countries. Given the increasingly high levels of antibiotic resistance worldwide and the challenge this presents for the treatment of bacterial infections, the rational use of antibiotics in humans and animals has been emphatically recommended in the spirit of a “One Health” approach. The aim of this study was to characterize antimicrobial resistance (AMR) genes and their frequencies from whole genome sequences of Escherichia coli isolated from both dairy cattle and human patients in central Zambia. Whole genome sequences of E. coli isolates from dairy cattle (n = 224) and from patients at a local hospital (n = 73) were compared for the presence of acquired AMR genes. In addition we analyzed the publicly available genomes of 317 human E. coli isolates from over the wider African continent. Both acquired antibiotic resistance genes and phylogroups were identified from de novo assemblies and SNP based phylogenetic analyses were used to visualize the distribution of resistance genes in E. coli isolates from the two hosts. Greater acquired AMR gene diversity was detected in human compared to bovine E. coli isolates across multiple classes of antibiotics with particular resistance genes for extended-spectrum beta lactamases (ESBL), quinolones, macrolides and fosfomycin only detected in E. coli genomes of human origin. The striking difference was that the Zambian or wider African human isolates were significantly more likely to possess multiple acquired AMR genes compared to the Zambian dairy cattle isolates. The median number of resistance genes in the Zambian cattle cohort was 0 (0–1 interquartile range), while in the Zambian human and wider African cohorts the medians and interquartile ranges were 6 (4–9) and 6 (0–8), respectively. The lower frequency and reduced diversity of acquired AMR genes in the dairy cattle isolates is concordant with relatively limited antibiotic use that we have documented in this region, especially among smallholder farmers. The relatively distinct resistant profiles in the two host populations also indicates limited sharing of strains or genes