127 research outputs found

    Determinants of manual control of water hyacinth expansion over the Lake Tana, Ethiopia

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    Water hyacinth is an exotic freshwater weed damaging wetland resources over the Lake Tana basin, Ethiopia. Different measures, including manual labour and harvesting machinery are in use to reduce its damage and expansion. Yet, the invasion of the weed appears expanding its scope across the wetlands of the Lake. This paper presented the study made to identify determinant factors affecting manual control of water hyacinth expansion over the Lake wetlands. It tried to analyse the expansion trend of the water hyacinth and community efforts to control its extension. Data were gathered from questionnaire surveys, group discussions, interviews and field observations. Descriptive statistics and binary logistic regression were used for data analysis. The study revealed that the water hyacinth cover in the Lake’s wetland increased from ≤10, 000 ha in 2011 to over 50, 000 ha in 2017. Wetland terrain, water depth, food availability, farming time, employment and government support were found significantly influencing the manual control practices of households. Hence, government support must increase to motivate people involvement in manual weed removal campaigns. Micro-relief maps and floating boats need be readily available to help participants easily identify risky terrains and expand the physical weed removal into the deeper waters.Key Words: Water hyacinth, Invasive weeds, Manual control, Wetlands, Lake Tana, Ethiopi

    The Community Ecology of Herbivore Regulation in an Agroecosystem: Lessons from Complex Systems

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    AbstractWhether an ecological community is controlled from above or below remains a popular framework that continues generating interesting research questions and takes on especially important meaning in agroecosystems. We describe the regulation from above of three coffee herbivores, a leaf herbivore (the green coffee scale, Coccus viridis), a seed predator (the coffee berry borer, Hypothenemus hampei), and a plant pathogen (the coffee rust disease, caused by Hemelia vastatrix) by various natural enemies, emphasizing the remarkable complexity involved. We emphasize the intersection of this classical question of ecology with the burgeoning field of complex systems, including references to chaos, critical transitions, hysteresis, basin or boundary collision, and spatial self-organization, all aimed at the applied question of pest control in the coffee agroecosystem

    Secure and scalable deduplication of horizontally partitioned health data for privacy-preserving distributed statistical computation

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    Background Techniques have been developed to compute statistics on distributed datasets without revealing private information except the statistical results. However, duplicate records in a distributed dataset may lead to incorrect statistical results. Therefore, to increase the accuracy of the statistical analysis of a distributed dataset, secure deduplication is an important preprocessing step. Methods We designed a secure protocol for the deduplication of horizontally partitioned datasets with deterministic record linkage algorithms. We provided a formal security analysis of the protocol in the presence of semi-honest adversaries. The protocol was implemented and deployed across three microbiology laboratories located in Norway, and we ran experiments on the datasets in which the number of records for each laboratory varied. Experiments were also performed on simulated microbiology datasets and data custodians connected through a local area network. Results The security analysis demonstrated that the protocol protects the privacy of individuals and data custodians under a semi-honest adversarial model. More precisely, the protocol remains secure with the collusion of up to N − 2 corrupt data custodians. The total runtime for the protocol scales linearly with the addition of data custodians and records. One million simulated records distributed across 20 data custodians were deduplicated within 45 s. The experimental results showed that the protocol is more efficient and scalable than previous protocols for the same problem. Conclusions The proposed deduplication protocol is efficient and scalable for practical uses while protecting the privacy of patients and data custodians

    Human Dimensions: Raising Black Excellence by Elevating Black Ecologists Through Collaboration, Celebration, and Promotion

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    While tutoring at inner-city schools in Cleveland, Ohio, as an undergraduate, I (Sealey) had the opportunity to promote science careers to Black students who were unsure if a career in STEM was suitable for them. They were excited to hear about my research and expeditions. However, when they asked me whether there were spaces that specifically promote scholars of color in scientific achievements, I had no good answer. It was not until I met Dr. Nyeema Harris, Assistant Professor at the University of Michigan (UM), that I would have the opportunity to develop my answer and refer students to the Black Ecologists Section (BES) of the Ecological Society of America (ESA)

    Effect of USAID-funded obstetric ultrasound service interventions on maternal and perinatal health outcomes at primary healthcare facilities in Ethiopia: a propensity score matching analysis.

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    OBJECTIVE: A dimensional shift in the health service delivery in the primary healthcare setting is required to raise maternal and child well-being. This study aimed to evaluate the effect of US Agency for International Development-funded obstetric ultrasound service on maternal and perinatal health outcomes at Ethiopia's primary healthcare facilities. DESIGN: We employed a quasi-experimental study design. SETTING: The study was conducted in primary health centres located in four regions of Ethiopia. PARTICIPANTS: We used 2 years' data of 1568 mothers from 13 intervention and 13 control primary health centres. Data were obtained from Vscan, antenatal care (ANC), delivery and postnatal care registers. INTERVENTION: Use of portable obstetric ultrasound service during pregnancy. OUTCOME MEASURES: The primary outcome variables include complete four ANC visits, referral during ANC, delivery in a health facility and having postnatal care and continuum of care. The secondary outcome variable was perinatal death. RESULTS: With the kernel matching approach, we have found that having four or more ANC visits was decreased after the intervention (average treatment effect (ATE): -0.20; 95% CI: -0.23 to -0.09), and the rest of the indicators, including referral during ANC (ATE: 0.01; 95% CI: 0.15 to 0.34), institutional delivery (ATE: 0.24; 95% CI: 0.15 to 0.34) and postnatal care (ATE: 0.26; 95% CI: 0.10 to 0.37), were significantly raised because of the intervention. Similarly, we have found that perinatal death dropped considerably due to the intervention. CONCLUSION: The findings show a consistent increase in maternal health service use because of the introduction of obstetric ultrasound services at the primary health centre level. Furthermore, early detection of complications and following referral for specialty care were found to be high. The consistent rise in maternal health service use indicators calls for additional trial to test the effect of obstetric ultrasound service in other locations of the country. Furthermore, evaluating the predictive values, sensitivity and specificity of the obstetric ultrasound service is important

    Rate-Induced Transitions in Networked Complex Adaptive Systems: Exploring Dynamics and Management Implications Across Ecological, Social, and Socioecological Systems

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    Complex adaptive systems (CASs), from ecosystems to economies, are open systems and inherently dependent on external conditions. While a system can transition from one state to another based on the magnitude of change in external conditions, the rate of change -- irrespective of magnitude -- may also lead to system state changes due to a phenomenon known as a rate-induced transition (RIT). This study presents a novel framework that captures RITs in CASs through a local model and a network extension where each node contributes to the structural adaptability of others. Our findings reveal how RITs occur at a critical environmental change rate, with lower-degree nodes tipping first due to fewer connections and reduced adaptive capacity. High-degree nodes tip later as their adaptability sources (lower-degree nodes) collapse. This pattern persists across various network structures. Our study calls for an extended perspective when managing CASs, emphasizing the need to focus not only on thresholds of external conditions but also the rate at which those conditions change, particularly in the context of the collapse of surrounding systems that contribute to the focal system's resilience. Our analytical method opens a path to designing management policies that mitigate RIT impacts and enhance resilience in ecological, social, and socioecological systems. These policies could include controlling environmental change rates, fostering system adaptability, implementing adaptive management strategies, and building capacity and knowledge exchange. Our study contributes to the understanding of RIT dynamics and informs effective management strategies for complex adaptive systems in the face of rapid environmental change.Comment: 25 pages, 4 figures, 1 box, supplementary informatio

    Stakeholders' views on the global guidelines for the sustainable use of non‐native trees

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    A large number of non‐native trees (NNTs) have been introduced globally and widely planted, contributing significantly to the world's economy. Although some of these species present a limited risk of spreading beyond their planting sites, a growing number of NNTs are spreading and becoming invasive leading to diverse negative impacts on biodiversity, ecosystem functions and human well‐being. To help minimize the negative impacts and maximize the economic benefits of NNTs, Brundu et al. developed eight guidelines for the sustainable use of NNTs globally—the Global Guidelines for the Use of NNTs (GG‐NNTs). Here, we used an online survey to assess perceptions of key stakeholders towards NNTs, and explore their knowledge of and compliance with the GG‐NNTs. Our results show that stakeholders are generally aware that NNTs can provide benefits and cause negative impacts, often simultaneously and they consider that their organization complies with existing regulations and voluntary agreements concerning NNTs. However, they are not aware of or do not apply most of the eight recommendations included in the GG‐NNTs. We conclude that effectively managing invasions linked to NNTs requires both more communication efforts using an array of channels for improving stakeholder awareness and implementation of simple measures to reduce NNT impacts (e.g. via GG‐NNTs), and a deeper understanding of the barriers and reluctance of stakeholders to manage NNT invasions. Read the free Plain Language Summary for this article on the Journal blog

    Field Attractants for Pachnoda interrupta Selected by Means of GC-EAD and Single Sensillum Screening

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    The sorghum chafer, Pachnoda interrupta Olivier (Coleoptera: Scarabaeidae: Cetoniinae), is a key pest on sorghum, Sorghum bicolor (L.) Moench (Poaceae), in Ethiopia. At present there is a lack of efficient control methods. Trapping shows promise for reduction of the pest population, but would benefit from the development of attractive lures. To find attractants that could be used for control of P. interrupta, either by mass trapping or by monitoring as part of integrated pest management, we screened headspace collections of sorghum and the highly attractive weed Abutilon figarianum Webb (Malvaceae) for antennal activity using gas chromatograph-coupled electroantennographic detection (GC-EAD). Compounds active in GC-EAD were identified by combined gas chromatography and mass spectrometry (GC-MS). Field trapping suggested that attraction is governed by a few influential compounds, rather than specific odor blends. Synthetic sorghum and abutilon odor blends were attractive, but neither blend outperformed the previously tested attractants eugenol and methyl salicylate, of which the latter also was part of the abutilon blend. The strong influence of single compounds led us to search for novel attractive compounds, and to investigate the role of individual olfactory receptor neurons (ORNs) in the perception of kairomones. We screened the response characteristics of ORNs to 82 putative kairomones in single sensillum recordings (SSR), and found a number of key ligand candidates for specific classes of ORNs. Out of these key ligand candidates, six previously untested compounds were selected for field trapping trials: anethole, benzaldehyde, racemic 2,3-butanediol, isoamyl alcohol, methyl benzoate and methyl octanoate. The compounds were selected on the basis that they activated different classes of ORNs, thus allowing us to test potential kairomones that activate large non-overlapping populations of the peripheral olfactory system, while avoiding redundant multiple activations of the same ORN type. Field trapping results revealed that racemic 2,3-butanediol is a powerful novel attractant for P. interrupta
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