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Surge of peatland destruction by an advancing front of artisanal gold mining in Amazonia
Get PDFAlluvial sediments bordering rivers of the southern Peruvian Amazon are enriched with gold, which has sustained an artisanal gold mining economy within a biodiversity hotspot for the past several decades. While it is clear that sweeping deforestation by miners has resulted in substantial loss of above-ground carbon stocks and increased greenhouse emissions, the region also harbors a sizable below-ground carbon stock in the form of peatlands, and how these have fared against decades of mining expansion is uncertain. Here, we use Landsat\u27s continuous archival record spanning over 35 years to monitor the expansion of gold mining in a major Amazonian peat complex along the alluvial plain of the Madre de Dios River. We detect over 550 ha of peatland surface area that has been lost to gold mining, potentially accounting for between 0.2 and 0.7 Tg of emitted below-ground carbon. Alarmingly, the majority of this loss (55%) has occurred within the past two years. Mining inside peatlands currently accounts for 9% of total mining, but projections suggest a 25% share by 2027 as mining within peatland is accelerating considerably faster than mining in the alluvial plain as a whole. The startling surge of peatland degradation is synchronous with the arrival of an aggressive mining front into the most distal reaches of the alluvial plain where peatlands are most abundant. Already, 63 of 219 peatlands in the alluvial plain show evidence of mining within their borders, putting over 10 000 ha of peatland area and between 3.5 and 14.5 TgC at imminent risk. The rapid proliferation of gold mining inside peatlands appears to be of such scope as to be an existential threat to the entire peatland complex
Development of Modified Japanese Versions of Questionnaires to Assess Physical and Cognitively Stimulating Activities
Get PDFIntroduction: Lifestyle factors such as physical and cognitively stimulating activities may protect against various diseases. However, only a few simple and validated questionnaires assess the lifestyle factors in Japan. Thus, we aimed to create Japanese versions of such questionnaires for assessing physical and cognitively stimulating activities. This study examined their inter-rater reliability and test-retest reproducibility.
Methods: We developed a Japanese version of questionnaires by translating the English questionnaire that assesses the frequency of several physical and cognitively stimulating activities. Additionally, the Japanese version assesses the duration of engagement in physical activities, and we have added mental activities such as meditation and Zen practice. The inter-rater reliability and test-retest reproducibility of evaluating the frequency, duration, frequency × duration of each physical activity, and frequency of each cognitively stimulating activity were tested in healthy volunteers.
Results: The study included 48 participants aged 25-67 years. We observed good inter-rater reliability and test-retest reproducibility for the physical and cognitively stimulating activity questionnaires. As a pilot approach, we calculated the Total Physical Activity Score (metabolic equivalents·min/week) with an intraclass correlation coefficient (ICC) (2,1) of 0.818 (95% confidence interval, 0.698-0.894), indicating good test-retest reproducibility.
Conclusions: The Japanese versions of questionnaires used to assess the frequency and duration of physical and cognitively stimulating activities generally have good inter-rater reliability and test-retest reproducibility. While introducing the duration of engagement might enable the estimation of the Total Physical Activity Score, further validation using objective measures of activities and other self-reported physical activity questionnaires is necessary, which is a limitation of this study
Nanoconfinement‐Induced Electrochemical Ion‐Solvent Cointercalation in Pillared Titanate Host Materials
Get PDFElectrochemical ion-solvent cointercalation reactions are an avenue to reach improved kinetics
compared to the corresponding intercalation of desolvated ions. Here, we demonstrate the impact of different structural pillar molecules on the electrochemical Li intercalation mechanism in expanded hydrogen titanate (HTO) electrode materials. We show that interlayer-expansion of HTO with organic pillars can enable cointercalation reactions. Their electrochemical reversibility is drastically improved when non-cross-linking pillars are employed that expand and separate the host material’s individual layers, underlining the impact of the electrochemo-mechanics of the nanoconfined interlayer space. This pillared HTO structure results in an increased Li storage capacity and reversibility compared to pristine HTO. We derive structural models of the pillared HTO host materials based on combined experiments and theoretical calculations, and employ electrochemical operando experiments to unambiguously demonstrate the nanoconfinement-induced cointercalation mechanism in pillared HTO electrode materials. The work demonstrates the potential of nanoconfined pillar molecules to modify host materials and enable highly reversible cointercalation reactions with improved capacity and kinetics
Partial correlation graphs for continuous-parameter time series
Get PDFIn this paper, we establish the partial correlation graph for multivariate continuous-time stochastic processes, assuming only that the underlying process is stationary and mean-square continuous with expectation zero and spectral density function. In the partial correlation graph, the vertices are the components of the process and the undirected edges represent partial correlations between the vertices. To define this graph, we therefore first introduce the partial correlation relation for continuous-time processes and provide several equivalent characterisations. In particular, we establish that the partial correlation relation defines a graphoid. The partial correlation graph additionally satisfies the usual Markov properties and the edges can be determined very easily via the inverse of the spectral density function. Throughout the paper we compare and relate the partial correlation graph to the mixed (local) orthogonality graph of Fasen-Hartmann and Schenk (Stoch Process Appl 179:104501, 2024. https://doi.org/10.1016/j.spa.2024.104501). Finally, as an example, we explicitly characterise and interpret the edges in the partial correlation graph for the popular multivariate continuous-time AR (MCAR) processes
Travelling breather solutions in waveguides for cubic nonlinear Maxwell equations with retarded material laws
Get PDFFor Maxwell’s equations with nonlinear polarization we prove the existence of time-periodic breather solutions travelling along slab or cylindrical waveguides. The solutions are TE-modes which are localized in space directions orthogonal to the direction of propagation. We assume a magnetically inactive and electrically nonlinear material law with a linear - and a cubic -contribution to the polarization. The -contribution may be retarded in time or instantaneous whereas the -contribution is always assumed to be retarded in time. We consider two different cubic nonlinearities which provide a variational structure under suitable assumptions on the retardation kernels. By choosing a sufficiently small propagation speed along the waveguide the second order formulation of the Maxwell system becomes essentially elliptic for the -field so that solutions can be constructed by the mountain pass theorem. The compactness issues arising in the variational method are overcome by either the cylindrical geometry itself or by extra assumptions on the linear and nonlinear parts of the polarization in case of the slab geometry. Our approach to breather solutions in the presence of time-retardation is systematic in the sense that we look for general conditions on the Fourier-coefficients in time of the retardation kernels. Our main existence result is complemented by concrete examples of coefficient functions and retardation kernels
Machine learning operations landscape: platforms and tools
Get PDFAs the field of machine learning advances, managing and monitoring intelligent models in production, also known as machine learning operations (MLOps), has become essential. Organizations are increasingly adopting artificial intelligence as a strategic tool, thus increasing the need for reliable, and scalable MLOps platforms. Consequently, every aspect of the machine learning life cycle, from workflow orchestration to performance monitoring, presents both challenges and opportunities that require sophisticated, flexible, and scalable technological solutions. This research addresses this demand by providing a comprehensive assessment framework of MLOps platforms highlighting the key features necessary for a robust MLOps solution. The paper examines 16 MLOps tools widely used, which revolve around capabilities within AI infrastructure management, including but not limited to experiment tracking, model deployment, and model inference. Our three-step evaluation framework starts with a feature analysis of the MLOps platforms, then GitHub stars growth assessment for adoption and prominence, and finally, a weighted scoring method to single out the most influential platforms. From this process, we derive valuable insights into the essential components of effective MLOps systems and provide a decision-making flowchart that simplifies platform selection. This framework provides hands-on guidance for organizations looking to initiate or enhance their MLOps strategies, whether they require an end-end solutions or specialized tools
Revealing the Mechanism and Kinetics of Fe 5 C 2 Formation From Ferrous Oxalate under CO 2 Fischer‐Tropsch Conditions Using Time‐Resolved In Situ X‐Ray Absorption Spectroscopy
Get PDFImproved oxidation behavior of M–20Cr–20Ta (M: Ni, Fe, Co) ternary alloys by formation of complex Cr–Ta-based oxides
Get PDFThe oxidation behavior and microstructural evolution of M–20Cr–20Ta (M: Ni, Fe, Co) alloys are investigated at 1000◦C and 1200◦C in Ar–20 vol% O2. High-temperature oxidation results in growth of bi-layered oxide scales, featuring an outer Cr₂O₃ layer and an inner Cr–Ta oxide layer. The Cr–Ta oxide layer consists of two distinct phases: CrTaO₄ and CrTa₂O₆. Significant improvements in oxidation resistance are found for Co and Fe alloys, in consequence of formation of the Cr–Ta oxides. At 1200◦C, oxidation kinetics approach a cubic growth law after an initial transient stage, underscoring the exceptional protective capabilities of the Cr–Ta oxides
