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A food web model of the Serengeti: stability, dynamics and indirect effects
Get PDFEffective conservation management of a complex ecosystem like the Serengeti can benefit from a systems-wide approach to interactions between functional groups. This study presents a food web model of the Serengeti based on generalised Lotka–Volterra equations parameterised using data from the literature. The internal equilibrium point is shown to be locally stable with a return time of 2.3 years. Global stability of the system is confirmed through permanence analysis, and the results were qualitatively robust to assumptions regarding consumers' functional response. Analysis of indirect effects following ‘press’ perturbations reveals that increasing a consumer's density raises resource density in about 30% of cases, while increasing a resource's density reduces the densities of consumers in a similar proportion of instances. This indicates the risks of assuming that the effect of a change in the density of one species on another is accurately reflected by the sign of any direct effect between them. Indeterminacy analysis shows the signs of these net effects in the Serengeti to be highly determinate; therefore, these conclusions are likely robust despite moderate levels of uncertainty in the quantified direct interactions. Future applications of this model could include exploring the impacts of burning or livestock grazing on the vegetation's ability to sustain the broader ecosystem
Sustainable Roof Design using PCM under Hot Climate Conditions
No full textHot climate areas worldwide are observing severe heat waves every year due to global warming and greenhouse gas emissions. The exploration of sustainable and passive solutions is a must in order to reduce the extreme impact of these heat waves and their impact on the electricity grid operation. This work proposes the use of a phase change materials (PCM) layer on the outside surface of a roof to passively reduce the indoor room temperature. Parafin wax and paraffin oil were mixed at different ratios and fabricated to panels with different thicknesses. The proposed solution is tested in a room located in Cairo, Egypt by adding different layer thicknesses of PW1 (4 cm) and PW2 (6 cm). Results exhibits that the using of PW1 and PW2 layers of PCMreduces the indoor temperature by 11−11.5∘C compared to non-AC conditions. Also, PW1 reduces the required air conditioner size from 5 HP to 3 HP, leading to a 50% reduction in electricity consumption. PW1 is more favourable over PW2 since it achieves similar thermal improvement,lowering peak temperatures by 11.5° C while having a thinner layer
Changing volatile emissions and sources along the Ethiopian Rift
No full textRift volcanoes are sites of intense volatile emissions. However, major uncertainties remain about the magnitude of rift volatile fluxes, particularly for greenhouse gases (e.g. CO₂) and whether along-rift variations in degassing relate to changing mantle sources and/or rifting processes (i.e. melt production and lithospheric thinning). Here, we investigate CO₂ flux and gas isotopes in Ethiopia; a mature, plume-influenced continental rift. We focus on one of the largest caldera volcanoes, Bora-Baricha-Tulu Moye (BBTM), which is situated in a region of high mantle melt production in the Central Main Ethiopian rift (∼500 km south-west the putative plume head). BBTM gases are characterized by plume-like ³He/⁴He values up to 17 Ra (the highest ever observed in Ethiopian Rift fumaroles) and we calculate total magmatic CO₂ flux of 757–901 t d⁻¹ (making BBTM the largest volcanic CO₂ emitter in the Ethiopian Rift). Using our CO₂ flux measurements, we estimate total CO₂ emissions from Ethiopia’s volcanic systems to be 2500–9200 kt yr⁻¹ and reveal important along-rift variation in CO₂ flux. High CO₂ flux sectors are found in Central Afar, as well as the Northern and Central Main Ethiopian Rift. These sectors are all regions of high partial melt content (evidenced by low seismic velocity in the underlying mantle) and also show the greatest ³He/⁴He values (>14 Ra). Cooccurrence of high mantle melt production, elevated CO₂ emissions and high ³He/⁴He demonstrates that in mature continental rifts carbon emissions and plume volatile contributions are particularly elevated in regions of greatest lithospheric thinning and mantle melting
Healthcare workload associated with transition onto kidney replacement therapy: a retrospective cohort study
No full textBackground and hypothesis:
Transition onto kidney replacement therapy (KRT) is a complex, intensive phase for patients with advanced chronic kidney disease (CKD), characterised by high healthcare utilisation. Frequent outpatient visits, surgical and radiological procedures, hospitalisations and haemodialysis (HD) sessions impose a significant time burden on patients. The concept of time toxicity is widely described in oncology, and captures the disruption to patients’ lives due to treatment-related demands. We aimed to quantify time- based healthcare workload during the transition onto KRT and identify patient characteristics associated with increased workload.
Methods:
We conducted a retrospective cohort study including all consecutive adults initiating KRT (haemodialysis (HD), peritoneal dialysis (PD), or pre-emptive transplantation (KTx)) in the Glasgow Renal and Transplant Unit between January 2015 and December 2019. Routinely collected electronic health record data were used to estimate time spent per month on healthcare-related activities (outpatient appointments, radiology, inpatient admissions, HD sessions, and travel) from 6 months pre- to 36 months post-KRT initiation. Workload was analysed as a time-based outcome (hours/month). Univariate analysis used Kruskal-Wallis testing; multivariate modelling employed negative binomial regression.
Results:
A total of 1,022 patients (58.6% male; median age 61 years) contributed over 1.1 million patient-days. Median healthcare workload peaked around KRT initiation and was highest in HD patients. Kidney transplantation was associated with markedly lower workload post-initiation (IRR 0.04). Increased workload was associated with female sex, polypharmacy (> 15 medications), late referral, older age (in maintenance phase), and modality change or failed transplant. Socioeconomic deprivation and primary renal disease were not significantly associated with higher workload.
Conclusion:
Healthcare workload during KRT transition is substantial and varies widely. Transplantation is associated with significantly lower workload. These findings support timely transplant planning and underscore the importance of considering the time burden of healthcare experienced by patients when discussing treatment options
Warming conditions increase foraging effort and alter nutritional state in two species of guano seabirds
No full textForaging movements are commonly driven by both extrinsic (e.g. climate or food availability) and intrinsic (e.g. breeding status or nutritional state) factors. In the Humboldt Current System (HCS), a highly productive upwelling system, Peruvian boobies (Sula variegata) and guanay cormorants (Phalacrocorax bougainvillii), are the most abundant guano seabirds. They prey mainly on Peruvian anchovy (Engraulis ringens), a cold-water fish species whose availability decreases during El Niño events (warmer conditions). We studied the relationship between extrinsic and intrinsic factors linked with foraging movements by means of biologging and analysis of metabolites, which reflect the nutritional states of both species during two contrasting breeding seasons (2018 [warm, high nest abandonment]; 2019 [normal, low nest abandonment]) at Guañape Norte Island, Peru (8°32’02.0"S 78°57’47.0"W). Peruvian boobies traveled greater distances on average (69.7 ± 2.90 km) than guanay cormorants (50.5 ± 2.13 km). Mean foraging trip duration for both species was greater during the warmer year (2.63 h ± 0.15 in 2018 vs. 1.97 h ± 0.1 in 2019), as expected due to reduced prey availability. Ketone concentrations were lower in boobies during the warm year, and cholesterol concentrations decreased with search effort. We conclude that Peruvian seabirds respond to warming of the HCS by increasing foraging effort, which is strongly linked to their nutritional status. Therefore, these warming effects on the system may be detrimental for population recovery in the long-term and need to be addressed in conservation planning such as protected area delimitation and fisheries management during the breeding season
Antibiotic prescribing and use in United Kingdom general practices in socio-economically deprived areas: a critical interpretive synthesis
No full textGeneral Practice is where most antibiotics are prescribed, yet a concerning trend has been observed – higher prescribing/use of antibiotics in socio-economically deprived settings. We aimed to critically interrogate the literature by exploring if prescribing/use of antibiotics throughout United Kingdom general practices is associated with deprivation, and if so, how. Five databases (CINAHL, Embase, Medline, Science Citation Index/Social Science Citation Index and Scopus) were searched. From 1464 gathered papers, 23 were included. 21 identified an association between deprivation and antibiotic prescribing/use and two papers found no association. From the 21, 15 utilized prescribing data, with 12 of these showing that as deprivation increased, so did prescribing, and three papers finding the opposite trend. Of the remaining 6 papers, four studies utilizing self-reported data identified a perceived risk of increased prescribing among socioeconomically deprived patients and two papers identified mixed results. Author interpretations of the relationship between antibiotic prescribing/use and deprivation considered overlapping clinical and social factors, which we then used to support our final synthesizing argument – observed prescribing variation is linked to inequalities and could be conceptualized as a form of “structural violence.” Research is needed to establish how structural inequalities shape the prescribing/use dynamic within these vulnerable communities
Healthy ageing in place: perspectives on age-friendliness in ‘local’ communities
Get PDFBackground:
Age-friendly communities are designed to support older adults in staying healthy, active, and engaged in society as they age. While the built environment plays an important role in their wellbeing, little is known about what shapes older adults’ views of community age-friendliness. This study explored how mid-to-older aged adults perceive community age-friendliness, and how these perceptions influence ageing in place.
Methods:
Semi-structured interviews (in-person/online) were conducted with 21 community-dwelling adults (55–75 years; mean age 65.0 ± 5.5) from two Scottish local authorities with high deprivation (September 2023 – March 2024). Guided by maps of their local area, barriers and facilitators to community age-friendliness were charted to the WHO Age-Friendly Cities, Place Standard and Ageing in Place frameworks, and perceptions of localness were explored.
Results:
Participants varied in physical activity, frailty, and loneliness levels, and experienced declining community age-friendliness. Physical barriers included neglected facilities, poorly accessible homes and spaces, and environmental hazards. Social barriers included declining access to social spaces due to rising costs, reduced hours and service closures. Service-related barriers included digital exclusion, ageism, safety concerns and reduced healthcare access. Perceptions of localness were shaped by (i) accessible and preferred transport options, with local areas shrinking as health declines; (ii) distance to essential services; and (iii) places where participants had social ties.
Conclusions:
The perceived deterioration of local places underpins a decline of community age-friendliness. To support older adults to age well, policymakers must consider the effects of declining mobility, access to- and closure -of essential facilities for older adults
Ensemble modelling based on transfer learning for enhancing crop mapping through synergistic integration of InSAR coherence and multispectral satellite data
No full textRecent advancements in remote sensing have enabled the integration of multi-temporal and multi-modal data for agricultural applications, such as crop mapping. This study proposes an innovative framework that explores the synergistic use of multi-temporal Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) coherence alongside Sentinel-2 and RapidEye multispectral data to enhance crop mapping in smallholder croplands in Bei’an county, China. Various deep learning models were evaluated, including the 3-Dimensional U-Net (3D U- Net), Transformer, Attention-based Long Short-Term Memory (AtLSTM), and a baseline machine learning Random Forest (RF) model, focusing on their transfer learning capabilities in complex intercropping patterns. Our new architecture, Transformer-AtLSTM-RF, uses ensemble learning to fuse features from different classifiers with a rule-based strategy, facilitating multi-source feature fusion for enhanced crop classification performance. Fine-tuning with region-specific data yielded high overall accuracy (OA), mean F1 score, and mean intersection over union (mIoU) for two test sites: site A (OA: 96.2%, mean F1: 92.7%, mIoU: 86.9%) and site B (OA: 90.7%, mean F1: 88.6%, mIoU: 79.7%). Additionally, we assessed feature importance by visualizing critical temporal features during the model inference process to improve an in-depth understanding of underlying patterns in the feature learning process. Our findings demonstrate the effectiveness of integrating time series SAR-derived and optical data with advanced models for mapping intercropping systems
Associations of chronic obstructive pulmonary disease with life satisfaction and self-rated health: quantifying the subjective burden in a population-based study
Get PDFIntroduction:
Subjective health and wellbeing measures such as self-rated health and life satisfaction are widely used in population health research and surveillance, yet their ability to reflect the lived burden of chronic disease has rarely been tested directly. This cross-sectional study examined whether life satisfaction and self-rated health differ between individuals with and without chronic obstructive pulmonary disease (COPD).
Methods:
We used pooled data from the 2018, 2019, 2021, and 2022 waves of the Scottish Health Survey, comprising 18,563 adults aged 16 years and over. COPD status was determined through self-report of a doctor diagnosis. Life satisfaction was categorised as low (0–7), moderate (8), or high (9–10), and self-rated health was grouped as very good/good, fair, or bad/very bad. Ordinal logistic regression was used to estimate unadjusted associations and generalised ordered logistic regression was applied for adjusted models, controlling for age, sex, smoking, ethnicity, education, mental health, area deprivation, and urban/rural residence.
Results:
Individuals with COPD had significantly poorer subjective wellbeing. In unadjusted models, individuals with COPD had 60% lower odds of reporting higher life satisfaction (OR = 0.40; 95% CI 0.35–0.46) and nearly nine times the odds of reporting worse self-rated health (OR = 8.70; 95% CI 7.64–9.92) compared to those without COPD. After adjustment, these associations remained strong: COPD was associated with 49% lower odds of higher life satisfaction (OR = 0.51; 95% CI 0.44–0.59) and over fourfold higher odds of poor self-rated health (OR = 4.24; 95% CI 3.68–4.89).
Conclusions:
Self-rated health and life satisfaction clearly distinguish individuals with COPD from those without, supporting their construct validity as indicators of chronic disease burden in population-based surveys. These brief measures may offer valuable tools for public health monitoring and evaluation of health inequalities
Achieving operational universality through a Turing complete chemputer
Get PDFThe most fundamental abstraction underlying all modern computers is the Turing Machine, that is, if any modern computer can simulate a Turing Machine, an equivalence which is called “Turing completeness”, it is theoretically possible to achieve any task that can be algorithmically described by executing a series of discrete unit operations. In chemistry, the ability to program chemical processes and ensure unit operations are understood at a high level of abstraction and then reduced to practice is extremely challenging. Herein, we exploit the concept of Turing completeness applied to robotic chemical platforms that execute unit operations to synthesize complex molecules using a chemically aware programming language, XDL. We leverage the concept of computability by computers to synthesizability of chemical compounds by automated synthesis machines. The results of an interactive demonstration of Turing completeness using the color gamut and conditional logic are presented to serve as a proxy for conceptual, chemical space exploration. This formal description establishes a formal framework in future chemical programming languages to ensure complex logic operations are expressed and executed correctly, with the possibility of error correction, in the autonomous pursuit of increasingly complex molecules
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