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Climate-Sensitive Health Outcomes in Kenya: A Scoping Review of Environmental Exposures and Health Outcomes Research, 2000–2024
Get PDFClimate change threatens health and social development gains in Kenya, necessitating health policy planning for risk reduction and mitigation. To understand the state of knowledge on climate-related health impacts in Kenya, a scoping review of 25 years of environmental health research was conducted. In compliance with a pre-registered protocol, nine bibliographic databases and grey literature sources were searched for articles published from 2000 to 2024. Of 19,234 articles screened, 816 full texts were reviewed in duplicate, and a final 348 articles underwent data extraction for topic categorisation, trend analysis, and narrative summary. Most of the studies (97%, n = 336) were journal articles, with 64% published after 2014 (n = 224). The health topics centred on vector-borne diseases (45%, n = 165), primarily vector abundance (n = 111) and malaria (n = 67), while mental health (n = 12) and heat exposure (n = 9) studies were less frequent. The research was geographically concentrated on the Lake Victoria Basin, Rift Valley, and Coastal regions, with fewer studies from the northern arid and semi-arid regions. The findings show a shift from a focus on infectious diseases towards broader non-communicable outcomes, as well as regional disparities in research coverage. This review highlights the development of baseline associations between environmental exposures and health outcomes in Kenya, providing a necessary foundation for evidence-informed climate change and health policy. However, challenges in data and study designs limit some of the evidentiary value
The efficacy of adjunctive Garcinia mangostana Linn. (mangosteen) pericarp extract for bipolar depression: 24-week randomised controlled trial
Get PDFBackground: Bipolar depression remains difficult to treat, and people often experience ongoing residual symptoms, decreased functioning and impaired quality of life. Adjunctive therapies targeting novel pathways can provide wider treatment options and improve clinical outcomes. Garcinia mangostana Linn. (mangosteen) pericarp has serotonogenic, antioxidant anti-inflammatory and neurogenic properties of relevance to the mechanisms of bipolar depression. Aims: The current 28-week randomised, multisite, double-blind, placebo-controlled trial investigated mangosteen pericarp extract as an adjunct to treatment-as-usual for treatment of bipolar depression. Method: This trial was prospectively registered on the Australia New Zealand Clinical Trials Registry (no. ACTRN12616000028404). Participants aged 18 years and older with a diagnosis of bipolar I or II and with at least moderate depressive symptoms were eligible for the study. A total of 1016 participants were initially approached or volunteered for the study, of whom 712 did not progress to screening, with an additional 152 screened out. Seventy participants were randomly allocated to mangosteen and 82 to a placebo control. Fifty participants in the mangosteen and 64 participants in the placebo condition completed the treatment period and were analysed. Results: Results indicated limited support for the primary hypothesis of superior depression symptom reduction following 24 weeks of treatment. Although overall changes in depressive symptoms did not substantially differ between conditions over the course of the trial, we observed significantly greater improvements for the mangosteen condition at 24 weeks, compared with baseline, for mood symptoms, clinical impressions of bipolar severity and social functioning compared with controls. These differences were attenuated at week 28 post-discontinuation assessment. Conclusions: Adjunctive mangosteen pericarp treatment appeared to have limited efficacy in mood and functional symptoms associated with bipolar disorder, but not with manic symptoms or quality of life, suggesting a novel therapeutic approach that should be verified by replication
A novel heuristic Morlet wavelet neural network design for the painlevé equation-II arising in nonlinear optics
Get PDFThe current investigations present the novel structure of Morlet wavelet neural network (MWNN) for the numerical solutions of Painlevé equation-II arising in nonlinear optics. An error based fitness function is constructed using the sense of differential model and its initial or boundary conditions, which is further optimized through the hybrid computing terminologies of the global search genetic algorithm (GA) and local search interior-point algorithm (IPA), i.e., GA-IPA. The precision of the process is observed through the overlapping of the proposed and reference results, and negligible absolute error. Moreover, the statistical analysis using the multiple independent runs is performed by different tests including Theil’s inequality coefficient, variance account for and semi inter-quartile range, which shows the dependability of the proposed MWNN-GA-IPA in order to Painlevé equation-II arising in nonlinear optics. The proposed MWNN-GA-IPA optics is discussed for the first time for solving the Painlevé equation-II arising in nonlinear
Summer warmth between 15,500 and 15,000 years ago enabled human repopulation of the northwest European margin
Get PDFHigh-magnitude decadal to centennial-scale abrupt changes in climate had a transformative effect on many past human populations. However, our understanding of these human/climate relationships is limited because robust tests of these linkages require region-specific quantified palaeoclimatic data with sufficient chronological precision to permit comparisons to the archaeological record. Here we present new high-resolution palaeoclimatic data and combine these with radiocarbon inventories of archaeological and faunal material, to test the relationship between abrupt warming and the ability of humans to rapidly repopulate the northwest margins of Europe (>50° N and encompassing the area of Britain, Ireland, the surrounding islands and the North Sea basin) after regional abandonment during the Last Glacial Maximum. We address the timing of this process and the relevance of the abrupt climate changes recorded in the Greenland ice cores. We use the IntCal20 radiocarbon calibration curve to show that the earliest human repopulation in this region occurred up to 500 years before the climate of Greenland warmed. However, our analyses show that parts of the northwest European margin had already experienced substantial summer warming by this time, probably driven by changes of sea-ice area in the eastern North Atlantic. The associated warming influenced the distribution of key hunter-gatherer prey species such as reindeer, which were a key resource for humans. Accordingly, this study highlights asynchrony in seasonal warming across the North Atlantic region during the last deglaciation and shows that this asynchrony permitted human exploitation of northwest European margin paraglacial landscapes by ~15,200 years before the present
Defying the iron curtain: émigré journals and their attempts to confront the post-war reality
No full textThis thesis investigates the political thought of émigré intellectuals from Poland, Czechoslovakia, and Yugoslavia, and the ways in which they addressed their home societies behind the Iron Curtain. The primary research is centred around Kultura, Svědectví, and Naša reč publications released between 1947- 1989. Reconciling transnational and national narratives this work will revisit the journals’ history and attempt to answer the following questions: How did Kultura, Svědectví, and Naša reč envision the advancement of their countries? What was the nature of the alternative trajectories that they offered? How did they envision the position of their homelands in Europe? In what ways did they try to advance their agenda? By analysing Kultura’s, Svědectví’s, and Naša reč’s influence, I aim to revise commonly held assumptions about the intellectual climate related to the ‘Iron Curtain’, where I will argue that exiled communities had greater impact than could be judged from their limited scale, geographical remoteness, and the prominence of local dissidents in their respective countries
Quantifying phenology in the deciduous tree and phytophagous insect system: a methodological comparison
Get PDFThe extent to which phenological synchrony between trophic levels may be disrupted by environmental change has been a topic of increased focus in recent years. Phenological associations between deciduous trees, phytophagous insects, and their consumers (e.g., passerine birds) have become one of the model systems for understanding this process. However, most existing research reports population-level associations rather than examining the smaller spatial scales at which these trophic interactions occur. Furthermore, a variety of methods have been used to measure phenology, particularly on producers and primary consumers, with little formal comparison. To investigate how different methods of measuring producer and primary consumer phenology influence our understanding of these biological relationships at the appropriate scale, we quantified phenological metrics for individual host trees and the phytophagous insects that depend on them in a deciduous woodland during spring 2023. We sampled 170 trees from six deciduous species in Wytham Woods, UK, deriving nine metrics of phenology from five distinct field methods: multispectral drone imaging (NDVI), hemispherical canopy photography, and bud-scoring observations to track tree phenology, as well as water traps and frass traps to monitor insect herbivore phenology. We assessed the reliability of these methods within both trophic levels and across tree species. We further evaluated the extent to which tree phenology metrics correlated with herbivore phenology at the level of individual trees and links to variation in subsequent herbivory rates across a subsample of 72 oak trees (Quercus robur). Our results illustrate how methodological choices can affect our ability to study the timing of trophic interactions and reveal fine-scale spatiotemporal variation in phenology across both trophic levels. We discuss the implications of these results for considering how the scale-dependence of trophic interactions may stabilize populations and shape broader-scale responses to environmental change
Assessing cardiopulmonary function: a model-based approach to interpreting gas exchange data
No full textNormal cardiopulmonary function is vital to life. The techniques currently used in the assessment of respiratory health and cardiac function have significant limitations. Conventional lung function measures are insensitive to early disease, whilst measures of cardiac function have limited applications due to being highly invasive or expensive to carry out. This thesis outlines the further development and clinical application of an emerging assessment of cardiac and respiratory function, Computed Cardiopulmonography (CCP).
CCP employs two novel technologies; the Molecular Flow Sensor (MFS), capable of measuring respiratory gas profiles with high precision, and a computational model of the cardiopulmonary
system. By optimising the model to accurately simulate the experimental data measured by the MFS, CCP develops a participant-specific model of an individual’s cardiopulmonary system. The
clinical potential of the parameters that define this model, specifically those pertaining to lung inhomogeneity, has previously been demonstrated and is expanded in this work.
Significant development of the cardiopulmonary model has been undertaken, with the improvements to model performance demonstrated in this thesis. Following this, CCP has been deployed in four different patient cohorts; it has been used to quantify gas exchange inefficiency in post-COVID patients, assess the lung inhomogeneity present in adult and paediatric patients with cystic fibrosis via simulation of another clinical test, and finally it has been used for the first time to assess cardiac function in patients with pulmonary hypertension
Cubes, grids and induced subgraphs: topics in extremal and probabilistic combinatorics
Get PDFWe begin by studying random subgraphs with a certain type of local dependence: a bond percolation model on a graph G is said to be 1-independent if for all vertex-disjoint sets of edges S1 and S2, the states of the edges in S1 are independent of the states of the edges in S2. In 2012, Balister and Bollobás defined pmax(G) to be the supremum of those p for which there exists a 1-independent bond percolation model on G in which each edge is present in the random subgraph with probability at least p, but which does not percolate (i.e. which does not with positive probability produce an infinite connected component). A fundamental and challenging problem in this area is to determine the value of pmax(G) when G is the lattice graph ℤ2. Since pmax(ℤn) ≤ pmax(ℤn−1), it is also of interest to establish the value of limn→∞ pmax(ℤn). We improve the known upper bounds on both quantities, the latter significantly. In proving these results, we also give an upper bound on the critical probability for a 1-independent model on the hypercube graph to contain a giant component.
Next, we analyse the typical structure of multi-agent strategic games in terms of the connectivity properties of their best-response graphs. Our central result shows that almost every game that is generic (that is, without indifferences) and has a pure Nash equilibrium and a "large" number of players is "connected", meaning that every action profile that is not a pure Nash equilibrium can reach every pure Nash equilibrium via a best-response path. This has important implications for dynamics in games. In particular, we show that there are simple, uncoupled, adaptive dynamics for which period-by-period play converges almost surely to a pure Nash equilibrium in almost every large generic game that has one. This contrasts with the known fact that there is no such dynamic that leads almost surely to a pure Nash equilibrium in every generic game that has one. For our characterisation of game connectivity we build on recent work of McDiarmid, Scott, and Withers on the component structure of dense random subgraphs of the hypercube.
Following this, we prove some results on the relationship between a graph's chromatic number and its induced subgraphs. We show that, for every graph F with at least one edge, there is a constant cF such that there are graphs of arbitrarily large chromatic number and the same clique number as F in which every F-free induced subgraph has chromatic number at most cF. This has important consequences for the study of χ-bounded graph classes and generalises recent theorems of Briański, Davies, and Walczak, and Carbonero, Hompe, Moore, and Spirkl. Our results imply that for every r ≥ 3 the class of Kr-free graphs has a very strong vertex Ramsey-type property, giving a generalisation of a result of Folkman from 1970. We also prove related results for tournaments, hypergraphs, and infinite families of graphs, and show an analogous statement for graphs where clique number is replaced by odd girth.
Finally, we consider the problem of maximising the number of subgraphs of an n-vertex planar graph that are isomorphic to some fixed graph H. We present results in two settings: that in which the copies of H are required to be induced and that in which they are not. In the induced setting, we determine the n-vertex extremal graphs for large n when H is the paw graph, and for all n when H is K4− or a star. In the not necessarily induced setting we determine the n-vertex extremal graphs for all n when H is the paw graph or K4−, with the cases where H is a star having been solved by Alon and Caro
Indium and Silver Recovery from Perovskite Thin Film Solar Cell Waste by Means of Nanofiltration
Get PDFDue to minimal material use and low-cost processing, next-generation thin film solar cells represent a promising alternative to traditional crystalline silicon solar cells. Among these, metal-halide perovskite solar cells have seen significant improvements in power conversion efficiency and are now on the verge of market entry. However, most efficient and stable perovskite solar cells contain lead in the perovskite absorber layer, along with indium and silver in their electrodes. This study demonstrates an environmentally benign recycling process for recovering all three elements from end-of-life perovskite solar cells. In short, the process consists of mechanical dismantling (milling), aqueous extraction/purification of PbI2, and acid extraction and purification of indium and silver by nanofiltration. After the quantitative recovery of lead as PbI2 (95 ± 5%), indium and silver were dissolved using nitric acid with recovery rates of 87 ± 7% for both metals. Life cycle assessment calculations were used to determine optimal conditions in terms of minimal environmental impact per gram of extracted element. After acid extraction, nanofiltration was employed using both custom-made layer-by-layer membranes and commercially available acid-resistant flat sheet membranes to separate indium from silver. Using an optimized membrane design, indium was almost entirely retained (96.9 ± 0.4%) using a layer-by-layer membrane at 50% permeate recovery. Hence, a twofold concentration of indium was achieved over the course of the filtration. In contrast, silver was not retained (retention of -7.6 ± 6.3%), resulting in a dilute Ag permeate. Using the commercial flat sheet membrane resulted in similar retention rates, with 98.5 ± 0.4% for indium and 5.8 ± 11.6% for silver. However, this came at the expense of considerably higher operating pressure (25 bar vs 5 bar) and lower flux (6 L/m2h vs 30 L/m2h), resulting in higher energy demand (72 Wh/L vs 9 Wh/L). Therefore, layer-by-layer membrane filtration proved to be the superior method for element recovery from perovskite photovoltaic devices. This study has shown that combining hydrometallurgical processing (aqueous and acidic extraction) with layer-by-layer membrane filtration offers an efficient and environmentally benign approach for metal recovery from end-of-life solar cells. Since indium and silver are also key elements for other thin film photovoltaic applications, layer-by-layer membrane filtration may represent a platform technology for future photovoltaic panel recycling
Daily night-time lights reveal prolonging global electric power system recovery times following tropical cyclone damage
Get PDFTropical cyclones are a leading cause of electric power outages, and the time required for power system recovery after storm damage is a critical measure of system resilience. However, systematically collected data on power supply disruptions are available for only a limited number of countries, leaving global patterns largely unexplored. In this study, we conducted the first global analysis of electric power system recovery times after 396 storms across 66 countries from 2012 to 2021, using satellite-based daily nighttime lights (NTLs) derived blackouts following storms. The median duration of blackouts detected worldwide was 4 d, with 5th–95th percentiles of 1–12 d. We found that high density urban areas had significant (P< 0.05) longer blackout events than low density urban areas and rural areas, which was driven by the upper tail of the events (i.e. 95 percentiles of, respectively, 16, 12, and 11 d). We also found that blackout durations have significantly (P < 0.05) increased over the study period across all levels of urbanization, at a similar rate of 0.9 ± 0.1 d per decade. The temporal variations (i.e. annual means) of blackout duration of high and low density urban clusters negatively correlated with storm travel speed, while those of low density urban clusters and rural areas positively correlated with pre-storm NTL (P ⩽ 0.05 in all cases). These findings highlight the pressing need to strengthen the resilience of electric power systems to storms, particularly as global reliance on electricity grows and storm activity patterns shift in response to climate change