Tropical Settings Research Articles

Evaluation of temperature corrections for pesticide half-lives in tropical and temperate soils.

Temperature is a key factor that influences pesticide degradation. Extrapolating degradation half-lives (DT50) measured at a given temperature to different temperatures remains challenging, especially for tropical conditions with high temperatures. In this study, the use of the standard Arrhenius equation for correcting temperature effects on pesticide degradation in soils was evaluated and its performance was compared with that of alternative Arrhenius-based equations. To do so, a database of 509 DT50 values measured between 5 and 35°C for 32 pesticides on tropical and temperate soils was compiled for the first time through an extensive literature search. The temperature correction models were fitted to the database using linear mixed regression approaches that included soil type and compound effects. No difference in the temperature dependence of DT50 between tropical and temperate soils was detected, regardless of the model. A comparison of the prediction performances of the models showed that constant activation energy (Ea) cannot be considered valid for the whole range of temperatures. The classical Arrhenius equation with an Ea of 65.4kJ.mol-1, as recommended by the European Food Safety Authority (EFSA), was shown to be valid for correcting the DT50 only for temperatures ranging from 5 to 20°C. However, for temperatures greater than 20°C, which are common in tropical environments, the median Ea was significantly lower at 10.3kJ.mol-1. These findings suggest the need to adapt the standard temperature correction of the European pesticide risk assessment temperature procedure when it is applied in tropical settings.

Genomics and transcriptomics to protect rice (Oryza sativa. L.) from abiotic stressors: -pathways to achieving zero hunger

More over half of the world's population depends on rice as a major food crop. Rice (Oryza sativa L.) is vulnerable to abiotic challenges including drought, cold, and salinity since it grown in semi-aquatic, tropical, or subtropical settings. Abiotic stress resistance has bred into rice plants since the earliest rice cultivation techniques. Prior to the discovery of the genome, abiotic stress-related genes were identified using forward genetic methods, and abiotic stress-tolerant lines have developed using traditional breeding methods. Dynamic transcriptome expression represents the degree of gene expression in a specific cell, tissue, or organ of an individual organism at a specific point in its growth and development. Transcriptomics can reveal the expression at the entire genome level during stressful conditions from the entire transcriptional level, which can be helpful in understanding the intricate regulatory network relating to the stress tolerance and adaptability of plants. Rice (Oryza sativa L.) gene families found comparatively using the reference genome sequences of other plant species, allowing for genome-wide identification. Transcriptomics via gene expression profiling which have recently dominated by RNA-seq complements genomic techniques. The identification of numerous important qtl,s genes, promoter elements, transcription factors and miRNAs involved in rice response to abiotic stress was made possible by all of these genomic and transcriptomic techniques. The use of several genomes and transcriptome methodologies to comprehend rice (Oryza sativa, L.) ability to withstand abiotic stress have been discussed in this review.

Management of febrile illness in rural Guinea over a seven-year period: A retrospective study.

Febrile illnesses constitute a major clinical challenge in tropical settings. We aimed to assess the frequency, presentation and management of febrile illness at two health facilities in Forécariah, Guinea, with a focus on appropriateness of antibiotic prescription. This was a retrospective study conducted in patient files in a health center and a district hospital. Proportions of antibiotic prescription were determined by age group and syndromes as well as appropriateness of antibiotic prescription using the WHO model list (2019). From 2014 to 2020, 23,583 of 62,185 (38.0%) visits were related to febrile illness. Most patients with fever were female (56.1%) and evaluated at the health center (81.0%). Gastrointestinal (40.6%) and respiratory syndromes (36.8%), and undifferentiated fever (30.0%) were the most common presentations. Malaria was confirmed in 61.3% of the cohort. Overall, the rate of antibiotic prescription was high (14,834/23,583, 62.9%), mostly among patients aged <5 years (5,285/7,566, 69.9%), those with respiratory (7,577/8,684, 87.3%) and gastrointestinal (6,324/9,585, 66.0%) syndromes. Moreover, 7,432/14,465 (51.4%) patients with malaria were also prescribed an antibiotic. Penicillin (42.0%), cotrimoxazole (26.3%) and quinolones (18.7%) were the most frequently prescribed antibiotics. Overall, appropriateness of antibiotic prescription was low (38.3%), and even more so in patients with respiratory (29.1%) and gastrointestinal (25.8%) syndromes. Febrile illness is a major cause of consultation in rural Guinea. Rate of antibiotic prescription was high, even in confirmed malaria and was often considered inappropriate. There is a pressing need to investigate the etiological spectrum and improve the diagnostic approach of febrile illness in Guinea.

Inconsistent response of taxonomic groups to space and environment in mediterranean and tropical pond metacommunities.

The metacommunity concept provides a theoretical framework that aims at explaining organism distributions by a combination of environmental filtering, dispersal, and drift. However, few works have attempted a multitaxon approach and even fewer have compared two distant biogeographical regions using the same methodology. We tested the expectation that temperate (mediterranean-climate) pond metacommunities would be more influenced by environmental and spatial processes than tropical ones, because of stronger environmental gradients and a greater isolation of waterbodies. However, the pattern should be different among groups of organisms depending on their dispersal abilities. We surveyed 30 tropical and 32 mediterranean temporary ponds from Costa Rica and Spain, respectively, and obtained data on 49 environmental variables. We characterized the biological communities of bacteria and archaea (from the water column and the sediments), phytoplankton, zooplankton, benthic invertebrates, amphibians and birds, and estimated the relative role of space and environment on metacommunity organization for each group and region, by means of variation partitioning using generalized additive models. Purely environmental effects were important in both tropical and mediterranean ponds, but stronger in the latter, probably due to their larger limnological heterogeneity. Spatially correlated environment and pure spatial effects were greater in the tropics, related to higher climatic heterogeneity and dispersal processes (e.g., restriction, surplus) acting at different scales. The variability between taxonomic groups in the contribution of spatial and environmental factors to metacommunity variation was very wide, but higher in active, compared with passive, dispersers. Higher environmental effects were observed in mediterranean passive dispersers, and higher spatial effects in tropical passive dispersers. The unexplained variation was larger in the tropical setting, suggesting a higher role for stochastic processes, unmeasured environmental factors, or biotic interactions in the tropics, although this difference affected some actively dispersing groups (insects and birds) more than passive dispersers. These results, despite our limitations in comparing only two regions, provide support, for a wide variety of aquatic organisms, for the classic view of stronger abiotic niche constraints in temperate areas compared with the tropics. The heterogeneous response of taxonomic groups between regions also points to a stronger influence of regional context than organism adaptations on metacommunity organization.

Syphylitical Myelopathies: Study of 8 observations at National Hospital Ignace Deen, University of Conakry

Introduction: Myelopathies occurring in the context of neurosyphilis have been poorly studied clinically, radiologically and in tropical settings. The diagnostic certainty of the syphilitic etiology of myelopathy is difficult to establish because of the multiplicity of causes of spinal cord damage. Patients and Methods: We carried out a retrospective study of 269 patients hospitalized for spinal cord disorders between January 2015 and December 2021, among whom 8 (eight) patients were identified for progressive syphilitic myelopathy diagnosed by the positivity of VDRL-TPHA serological reactions in the blood and cerebrospinal fluid and radiological data. Magnetic resonance imaging was performed in all patients. Results: The neurological signs were limited to the existence of a sensory-motor spinal semiology in particular, paraparesis with sphincter disorders, especially moderate urinary disorders, without an obvious infectious syndrome in a context of positive serological reactions VDRL-TPHA in the blood and cerebrovascular fluid. spinal. Lumbar puncture shows hypercellularity with lymphocyte predominance on average 65% and hyperproteinorachia varying from 0.98 to 1.36 g/l. magnetic resonance imaging performed in all patients contributed to the diagnosis by showing hypersignals in T2, expression of more or less extensive lesions on several segments.

River avulsions and megafan development triggered by high recurrent explosive volcanism

Megafans are ever-evolving landforms and sedimentary bodies produced by rivers that regularly change their courses through avulsions, in which the processes that cause the avulsions and their rates are tightly linked to the formation and evolution of the fans. The commonly cited condition required for the formation of megafans is a highly variable climate setting (monsoonal) which results in variable discharge and sediment transport capacity. However, some megafans occur in tropical settings in rivers with lower discharge variability but high sediment loads due to input from volcanic or tectonically active sources. We examine the Santa Clara Megafan (Costa Rica) to establish a model of explosive volcanism-driven megafan evolution, an alternative model to the climate-driven one. Studying chronological, archaeological, historical and remote sensing data we infer that major avulsions and shifts in the main rivers of this megafan are temporally and spatially correlated to strong eruptions (VEI ≥ 3). Furthermore, a period of ca. 1700 years with few changes in the fluvial system of the eastern sector of the megafan coincides with a low volcanic activity in its source area (i.e. Turrialba Volcano). The megafan avulsion rate was estimated as ∼1 major avulsion per century in the last five centuries, when four strong eruptions (∼0.8 eruptions/century) took place. These shifts in the rivers in response to the volcanic activity produced the activation or abandonment of megafan sedimentary lobes at a secular pace. The record of these changes will support future archaeological studies and lahar hazard assessments. Furthermore, the Santa Clara Megafan provides a model to explain the formation of megafans on Earth or on other planets through non-climatic processes.

The influence of air quality and meteorological variations on influenza A and B virus infections in a paediatric population in Singapore

IntroductionInfluenza is an important cause of paediatric illness across the globe. However, information about the relationships between air pollution, meteorological variability and paediatric influenza A and B infections in tropical settings is limited. MethodsWe analysed all daily reports of influenza A and B infections in children <5 years old obtained from the largest specialist women and children's hospital in Singapore. In separate negative binomial regression models, we assessed the dependence of paediatric influenza A and B infections on air quality and meteorological variability, using multivariable fractional polynomial modelling and adjusting for time-varying confounders. ResultsApproximately 80% of 7329 laboratory-confirmed reports were caused by influenza A. We observed positive associations between sulphur dioxide (SO2) exposure and the subsequent risk of infection with both influenza types. We observed evidence of a harvesting effect of SO2 on Influenza A but not Influenza B. Ambient temperature was associated with a decline in influenza A reports (Relative Risk at lag 5 [RRlag5]: 0.949, 95% CI: 0.916–0.983). Rainfall was positively associated with a subsequent increase in influenza A reports (RRlag3: 1.044, 95% CI: 1.017–1.071). Nitrogen dioxide (NO2) concentration was positively associated with influenza B reports (RRlag5: 1.015, 95% CI: 1.005–1.025). There was a non-linear association between CO and influenza B reports. Absolute humidity increased the ensuing risk of influenza B (RRlag5: 4.799, 95% CI: 2.277–10.118). Influenza A and B infections displayed dissimilar but predictable within-year seasonal patterns. ConclusionsWe observed different independent associations between air quality and meteorological variability with paediatric influenza A and B infections. Anticipated seasonal infection peaks and variations in air quality and meteorological parameters can inform the timing of community measures aimed at reducing influenza infection risk.

Effects of Green Roof in Reducing Surface Temperature and Addressing Urban Heat Island in Tropical Climate of Malaysia

Urban heat island (UHI) in cities across Malaysia has worsened due to rapid development and construction. Previous research highlight temperature difference between Putrajaya and its suburban neighbouring area is as high as 5˚C. Green roofs in urban areas can be used as a green intervention strategy to reduce UHI impact by increasing air moisture and surface wetness through its plants, which consequently decreases surrounding air and surface temperature. Green roofs also provide additional insulation that reduces heat transfer into buildings, therefore reducing cooling demand and operational energy in buildings. Conventional building roofs in tropical climate have measured surface temperature up to 60˚C, compared to surrounding irrigated grass and water bodies that are measured as low as 15˚C. This paper compared surface temperatures of green roof and conventional non-green roof case studies in a tropical climate setting, to combat urban heat island effect. A triangulation technique was adopted, using a case study analysis with an in-depth structured interview and physical fieldwork investigation. The findings concluded that green roofs had significantly lower surface temperature compared to non-green flat roof. This paper provides evidence that supports green roof as a green intervention strategy in reducing urban heat island and encourage building designers to maximize under-utilized spaces of roofs to increase urban greenery coverage.

The prevalence of Schistosoma mansoni infection among adults with chronic non-communicable diseases in Malawi

BackgroundSchistosomiasis is a parasitic infectious disease caused by flatworms of the Schistosoma genus. The global burden of schistosomiasis is high. In Malawi, schistosomiasis is among the top 20 causes of outpatient department visits in health facilities. Schistosomiasis is among the most important but neglected causes of non-communicable diseases (NCD) peculiar to tropical endemic settings. While much is known about the contribution of S. haematobium to the NCD burden in Malawi, the role of S. mansoni remains largely unknown.MethodsWe conducted a cross-sectional study at Mangochi District Hospital. Adults over 18 years diagnosed with NCDs (n = 414), admitted or attending weekly outpatient clinics were recruited between August 2021 and February 2022. Data were collected on sociodemographic characteristics, medical history, body weight, blood pressure, and fasting blood glucose. Stool and midstream urine were collected for Kato–Katz (KK) microscopy and urine point of care-circulating cathodic antigen (POC-CCA) tests, respectively. We computed prevalence of S. mansoni as number of positive KK and CCA tests, each divided by total submitted samples. Univariate and multivariable logistic regression were done to evaluate risk factors of NCDs and association between S. mansoni infection and NCDs.ResultsWe recruited 414 participants, mean age 57 years (SD 16), 67% of whom were female. Prevalence of S. mansoni based on urine CCA was 15% (95% CI: 11–19) and 0% on KK microscopy. Hypertension was the most common condition with a prevalence of 85% (95% CI: 81–89), followed by diabetes mellitus with a prevalence of 42% (95% CI: 37–46) and heart disease with a prevalence of 3% (95% CI: 2–5). S. mansoni infection was not significantly associated with hypertension (OR: 1.2, 95% CI: 0.5–3.1), diabetes (OR: 0.6, 95% CI: 0.3–1.10) or heart disease (OR: 2.0, 95% CI: 0.4–10).ConclusionsWe observed moderate prevalence of S. mansoni infection among adults in the study per WHO classification of endemicity. This is within the range observed in children in Mangochi from 10 to 56.7%.

Mainland-coastal interactions in East Borneo: Inter-site comparison and Bayesian chronological models of two Late Pleistocene–Holocene sequences (Liang Abu and Kimanis rock shelters)

In recent decades, East Borneo has become an increasingly important archaeological “hot-spot” in Island Southeast Asia as a result of early dates for rock art ca. 38,000 BP and the greater number of excavated sites that support a much longer period of human occupation. However, the chronology of settlement and adaptation to environmental changes during the Pleistocene–Holocene transition is still poorly known. Here we report on an excavation at the Liang Abu rock shelter which has contexts dating from the Late Pleistocene (12,660 ± 58 uncal. BP) to the present day, indicating a terminus ante quem (TAQ) for human occupation at 23,790 BP. We present the results of an attempt to systematically integrate and compare data from Liang Abu and Kimanis, a geographically close site with a previously published sequence. Particular attention is paid to post-depositional issues in tropical settings and to data compatibility, reuse, and reproducibility, relying on open-source software for data processing (R scripts) and Bayesian chronological modeling. Two Bayesian models are built and compared using the ChronoModel software, which can handle outliers and uncertainty (e.g., freshwater reservoir effect). This first inter-site comparison for Borneo results in a new chronology of human settlement and mainland–coastal interactions in East Borneo and paves the way for future regional synthesis.

Geoheritage and geodiversity aspects of catastrophic volcanic eruptions: Lessons from the 15th of January 2022 Hunga Tonga - Hunga Ha'apai eruption, SW Pacific

On the 15th of January 2022, a massive hydrovolcanic eruption at Hunga Tonga-Hunga Ha'apai in Tonga (SW Pacific) sent shockwaves in the near-field regime, close to the volcano. The far-field disturbances that encircled the globe were of a slower velocity. The most prominent disturbance was the Lamb wave, with the rest of the disturbances being a variety of gravity waves travelled around the globe and instantly became an international headline story. The eruption generated atmospheric pressure waves recorded multiple times across the globe, triggered a tsunami, and injected highly fragmented pyroclasts up to 55 km into the atmosphere. Enduring several hours, a series of individual large blasts generated an unprecedented lightning “show” recorded by the lightning detection networks, such as Vaisala. Consequences were devastating to the local community and the tsunami was felt across the Pacific and beyond. The impact of the eruption was truly global and comparable to the Krakatau 1883 eruption. A question we pose here is which geoheritage elements were created and preserved after the eruption. First reports confirmed that while fine ash was reported on land about 100 km from the source, most deposits were thin (mm-cm thick). This indicates that it is unlikely that any major section will be preserved, especially in the years following the event given the tropical setting. In addition, most of the ash fell into the Pacific Ocean, leaving no visible mark of this catastrophe. Unfortunately, the proximal region (e.g., the vent site) has also been destroyed, leaving only limited in-situ geoheritage elements likely to be accessible in the future. This poses a problem for human societal memory, as major catastrophic events in the collective memory of a community may only persist for a few decades, even when significant eruptive features may be preserved. Without “visible” geoheritage elements, this time will likely be much shorter. Geocultural elements (oral traditions or cultural activities) are likely to preserve and transmit information within the local communities for a longer period, but their accessibility and decoding may face difficulties in the absence of physically preserved evidence. Therefore, we consider it is important to trace and explore these geocultural elements through a mix of traditional and western approaches of community engaged activities. For example, the Pacific region has experienced several similar large-scale eruptions in historic times, and a few of them resulted in preserved geoheritage elements such as superb sections of the 1452–53 CE Kuwae eruption in Vanuatu. While these sites are locally known, their appearance and their geological context are not evidently and immediately considered as part of a major volcanic system, as they do not fit the common human perception of volcanoes as large conical mountains. Such visual perceptions do not align with the common near-sea level/shallow subaqueous caldera-dominated systems such as the location of the recent Tonga event. In achieving a better understanding in local communities of this type of geohazard, the geoheritage and geoeducation values of those rare geosites will increase significantly over time.

Isotopic fingerprinting of dual monsoon moisture sources, evapotranspiration process and microclimate manifestation over the tropical rainforest region, western part of the Western Ghats, India

The changes in precipitation pattern provide an understanding on the hydroclimatic response to global warming during the Anthropocene. The present study investigates sources of precipitation moisture for the Indian Monsoon and the local environmental mechanisms controlling its distribution over the southwest coast of India. This is achieved by the characterization of stable isotope ratios of oxygen (δ18O) and hydrogen (δ2H) in rainwater samples collected from a high humid tropical setting (Swarna-Madisal river basin) of the Western Ghats, South India and another station further south (Bakrabail, southern edge of Nethravati river basin). This study contributes to the detailed investigation on rainwater isotopic composition and microclimate characteristics which is lacking in the humid west coast region. The rainwater isotopic composition of coast was close to that of the Arabian Sea water and reflected the first condensate of vapours which were originally formed under fast evaporation at the nearby ocean. In inland location, the higher d-excess values reflect continental moisture recycling. Evapotranspiration has led to higher kinetic fractionation effect in the inland region. The isotopic storm effect during winter monsoon season suggested the rain distribution from saturated air masses formed under deep convective effect in the Bay of Bengal. The overall local meteoric water line (LMWL) in the Swarna-Madisal basin was found to be δ2H = {(7.2 × δ18O) + 7.5}, R2 = 0.98. Further south, the LMWL of Bakrabail was, δ2H = {(8.19 × δ18O) + 16.1}, R2 = 0.98 for annual observation and displayed minimal variability for inter-seasonal slopes (7.73 for summer monsoon, 8.48 for winter monsoon and 8.36 for pre-monsoon) and intercepts (15.6 for summer monsoon, 17.8 for winter monsoon and 15.5 for pre-monsoon). In regions of vegetation dominance and humid climate, the prevailing local air mass masked the rain-out effect of marine air mass as well as the amount effect which support microclimatic settings at the local precipitation sites in southwest India. The time and space variability of regional moisture circulation in controlling atmospheric water balance has been deduced in this study. Thus, the high efficacy of stable isotopes in tracing the manifestation of microclimate in the humid tropics has been demonstrated.

“Numberless Little Risks”: ‘Tropical Exposure’ in Globalizing Actuarial Discourse, 1852–1947

I argue that life insurance and imperial meaning making are deeply implicated in each other. As life insurance expanded internationally in the nineteenth century, and as insurers became advocates of White settlement, they grappled with what actuarial science meant in the context of their orientalist conceptions of colonial populations. In particular, actuaries were concerned with tropical markets and the racialized/exceptionalized differences they perceived in those markets. To address these tensions, insurers attempted two strategies: (1) incorporating tropical rates as additional premiums designed to cover the “extra mortality” of tropical markets; and (2) advocating for social practices of “sanitary progress” related to public health and sanitation. These practices, framed in orientalist terms, were not adopted in any smooth manner but in fumbling and meandering ways as insurers tried to understand what kinds of lives tropical settlers might be and how those lives might be priced. They eventually liberalized life insurance rates for White settlers in tropical settings, but insurers then confronted questions on how newly socialized “native” lives might be rendered calculable. This story of tropical exposure in globalizing actuarial discourse reinforces the ways in which race and racialized/exceptionalized differences were at the core of life insurance and the calculative devices it assembled between 1852 and 1947.

SARS-CoV-2 seropositivity and COVID-19 among 5 years-old Amazonian children and their association with poverty and food insecurity.

The epidemiology of childhood SARS-CoV-2 infection and COVID-19-related illness remains little studied in high-transmission tropical settings, partly due to the less severe clinical manifestations typically developed by children and the limited availability of diagnostic tests. To address this knowledge gap, we investigate the prevalence and predictors of SARS-CoV-2 infection (either symptomatic or not) and disease in 5 years-old Amazonian children. We retrospectively estimated SARS-CoV-2 attack rates and the proportion of infections leading to COVID-19-related illness among 660 participants in a population-based birth cohort study in the Juruá Valley, Amazonian Brazil. Children were physically examined, tested for SARS-CoV-2 IgG and IgM antibodies, and had a comprehensive health questionnaire administered during a follow-up visit at the age of 5 years carried out in January or June-July 2021. We found serological evidence of past SARS-CoV-2 infection in 297 (45.0%; 95% confidence interval [CI], 41.2-48.9%) of 660 cohort participants, but only 15 (5.1%; 95% CI, 2.9-8.2%) seropositive children had a prior medical diagnosis of COVID-19 reported by their mothers or guardians. The period prevalence of clinically apparent COVID-19, defined as the presence of specific antibodies plus one or more clinical symptoms suggestive of COVID-19 (cough, shortness of breath, and loss of taste or smell) reported by their mothers or guardians since the pandemic onset, was estimated at 7.3% (95% CI, 5.4-9.5%). Importantly, children from the poorest households and those with less educated mothers were significantly more likely to be seropositive, after controlling for potential confounders by mixed-effects multiple Poisson regression analysis. Likewise, the period prevalence of COVID-19 was 1.8-fold (95%, CI 1.2-2.6-fold) higher among cohort participants exposed to food insecurity and 3.0-fold (95% CI, 2.8-3.5-fold) higher among those born to non-White mothers. Finally, children exposed to household and family contacts who had COVID-19 were at an increased risk of being SARS-CoV-2 seropositive and-even more markedly-of having had clinically apparent COVID-19 by the age of 5 years. Childhood SARS-CoV-2 infection and COVID-19-associated illness are substantially underdiagnosed and underreported in the Amazon. Children in the most socioeconomically vulnerable households are disproportionately affected by SARS-CoV-2 infection and disease.

Tropical Geometric Variation of Tree Shapes

We study the behavior of phylogenetic tree shapes in the tropical geometric interpretation of tree space. Tree shapes are formally referred to as tree topologies; a tree topology can also be thought of as a tree combinatorial type, which is given by the tree’s branching configuration and leaf labeling. We use the tropical line segment as a framework to define notions of variance as well as invariance of tree topologies: we provide a combinatorial search theorem that describes all tree topologies occurring along a tropical line segment, as well as a setting under which tree topologies do not change along a tropical line segment. Our study is motivated by comparison to the moduli space endowed with a geodesic metric proposed by Billera, Holmes, and Vogtmann (referred to as BHV space); we consider the tropical geometric setting as an alternative framework to BHV space for sets of phylogenetic trees. We give an algorithm to compute tropical line segments which is lower in computational complexity than the fastest method currently available for BHV geodesics and show that its trajectory behaves more subtly: while the BHV geodesic traverses the origin for vastly different tree topologies, the tropical line segment bypasses it.

Clinical Performance of Three Commercial SARS-CoV-2 Rapid Antigen Tests for Community-Dwelling Individuals in a Tropical Setting.

During the second year of the COVID-19 pandemic, the use of Rapid Diagnosis Antigen Tests (RDAgTs) for SARS-CoV-2 detection has substantially increased as some of the brands available in the market were certified for clinical use by international regulatory agencies. RDAgTs are a fast and cheap tool for SARS-CoV-2 surveillance with great potential to improve testing capacities in middle- and low-income countries compared to the gold standard RT-qPCR. However, as the clinical performance of RDAgTs has been shown to vary greatly between the commercial brands available, evaluation studies are necessary. Moreover, the available evaluation has been done in high-income countries while SARS-CoV-2 transmission is also actively happening in developing countries, many of which are located in tropical latitudes where cross-reactivity with other infectious agents is highly prevalent, which could compromise RDAgT specificity. Moreover, unreported mutations and/or new SARS-CoV-2 variants may compromise RDAgT sensitivity as genomic surveillance is limited in these settings. Here we describe a multicenter and manufacturer‐independent evaluation of the clinical performance and analytical sensitivity of three different RDAgTs brands available in South America from three companies, Rapigen (South Korea), SD-Biosensor (South Korea), and Certest (Spain), compared to the gold standard RT-qPCR. A total number of 1,646 nasopharyngeal swabs from community-dwelling individuals were included in the study, and 379 of them were SARS-CoV-2 positive by RT-qPCR. The overall sensitivity for each RDAgT was 79% (IC95%: 72 - 86.2), 64.2% (IC95%: 56.7 - 71.6), and 45.8% (IC95%: 35.8 - 55.8) for SD-Biosensor, Certest, and Rapigen, respectively. The overall specificity for each RDAgT was 100%, 97.7% (IC95%: 96.8 - 98.6), and 100% for SD-Biosensor, Certest, and Rapigen, respectively. However, the limit of detection (LoD) to achieve a sensitivity over 90% was substantially lower for Certest RDAgT (102 copies/uL) compared to SD-Biosensor (103 copies/uL) or Rapigen (106 copies/uL) RDAgTs, considering that the gold standard RT-qPCR method used in this study has a high sensitivity of 97.7% and low LoD of 5 copies/uL. Additionally, the Certest RDAgT also showed an improved sensitivity up to 79.7% (IC95%: 70.2 – 89.2) for symptomatic individuals. Finally, the slight reduction in specificity for Certest RDAgTs was only associated with one of the laboratories performing this study, pointing out the need for locally assessed evaluation for RDAgTs like this one carried out in Ecuador. In conclusion, two of the three the RDAgTs tested in this study are a fast, cheap, and point of care tool for SARS-CoV-2 surveillance and reliable enough to detect SARS-CoV-2 infectious individuals.

A Pilot Comparative Study of Submerge vs. Non- Submerg Saturated Salt Solution Human Cadavers Embalming Method by Gross, Histological, and Microbiological Evaluation

Objective: To investigate and develop the saturated salt embalming method and evaluate the cadavers.Materials and Methods: Eight cadavers were embalmed with a saturated salt solution (SSS) by submerged (SG, N=2) and non-submerged (NSG, N=6), then evaluated by gross dissection, which compared to living humans, fresh and Thiel’s cadavers. The histological evaluation was compared to textbook pictures. The assessments were recorded on a Likert scale from 0 (no resemblance) to 5 (most resemblance). Pre-and post-embalming swabs were collected for bacterial and fungal cultures and lung tissues for acid-fast staining and mycobacterial cultures. Comparisons between the evaluated items were performed using the Kruskal–Wallis test. The Likert scale results were reported by percentage.Results: The submerge method (N=2) was terminated after three months of embalming because it showed insufficient quality for dissection. Six cadavers in NSG had gross tissue qualities that resembled living humans or fresh cadavers on a scale of 3 or 4. NSG had excellent joint flexibility. The histological tissues showed similarity to textbook pictures, with a scale of 4 or 5. There were bacterial and fungal cultures at the end of embalming. The pathogenic bacteria were Clostridium perfringens and Pseudomonas aeruginosa. Mycobacterium cultures were negative.Conclusion: Injected SSS, 80% total body water volume, is a promising embalming method that yields cadavers with high tissue quality, flexible joints, and good histological structures. However, this technique cannot eliminate bacteria and normal flora. It may result from the tropical climate setting.

Bronchus sign on HRCT thorax

Tuberculosis is the most common diagnosis in India in presence of constitutional symptoms such as cough, fever, and weight loss with lung parenchymal abnormality irrespective of microscopy or nucleic acid amplification test abnormalities in high TB prevalent tropical settings. Pulmonary manifestations of systemic vasculitis have very diverse involvement ranging from the nodule to consolidation. Bronchus sign is classically described in lung malignancies than Wegener disease. The acino-nodular pattern is classical of pulmonary tuberculosis, sometimes documented in fungal infections. In this case report, a 45-year-old female, presented with constitutional symptoms with lung parenchymal nodules, without mycobacterial microscopic or genome documentation, received empirical antituberculosis treatment with the progression of the disease without clinical or radiological response. Bronchoscopy workup is inconclusive and tropical screen for bacterial, fungal, TB, and malignancy was negative. Vasculitis workup was done in view of the presence of persistent fever and documented PR3-ANCA positive with very highly raised titers. We have started on steroid and cyclophosphamide and clinical response documented with near-complete resolution of shadows in 12 weeks. Pulmonary manifestations of Wegener disease are rare and underestimated and early pickup of the entity in course of illness will have a good outcome with an excellent prognosis.

The Adaptability of PVC Mesh as Recycled Textile Waste towards Innovative Tropical Building Façade

Textile fibres are commodity materials that will continue to be required in vast numbers for various applications by society but accumulate colossal waste. Upcycled textile waste possesses high potential in building construction through coating application. This research aims to establish the use of PVC mesh textile waste as an innovative textile facade for Malaysian buildings. Content analysis is conducted to evaluate different textile façade construction performing architectural functions. The overall result concludes that PVC mesh covers all aspects in balance as an innovative building façade responding to the needs of the tropical climate setting in Malaysia. Keywords: Textile waste, Building façade, Recycled Material, Textile facade eISSN: 2398-4287 © 2022. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians/Africans/Arabians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning &amp; Surveying, Universiti Teknologi MARA, Malaysia. DOI: https://doi.org/10.21834/ebpj.v7i20.3505

Control of regional climate on carbon and nitrogen turnover and their stable isotopic compositions in Indian soils

Stable isotopic analysis of carbon (C) and nitrogen (N) has helped to predict climate specific response of biological mediators of C and N cycles, and thus, turnover and availability of these elements in soils. However, application of general isotopic trends to soils of different ecosystems remains undetermined pertaining to inadequate data from vast eco-regions, including the Indian subcontinent. The present study focuses on filling this data gap through isotopic analysis of soils from the arid, humid, and montane regions of India to understand the distribution and availability of total organic carbon (TOC) and total nitrogen (TN) under different temperature and precipitation conditions in an understudied tropical region. Our results for arid soils showed low TOC and TN contents with high δ13C and δ15N indicating active mineralization under limited organic matter supply. Contrarily, humid soils showed high concentrations of TOC and TN with low δ13C and δ15N indicating conservative N cycle. Isotopic signatures of montane soils showed spread over both arid and humid soils signifying higher control of edaphic factors over climate in the organic matter turnover in montane soils. Absence of climate specific isotopic pattern in the montane soils suggests careful application and interpretation of stable isotopic techniques in such regions. In our results, we find partial confirmation that climate is a prominent control of C and N turnover but also evidence for the importance of edaphic and other local factors, especially in the montane region. This work fills the knowledge gap in an understudied region and confirms that even within a larger tropical setting, the regional climate regulates the elemental biogeochemistry and organic matter dynamics of soils.