Various methodologies exist for upgrading biogas, each differing in their capacity to valorise CO2. Certain processes merely separate CO2 from CH4 without converting it. Conversely, other pathways transform biogas into synthesis gas, thereby valorizing CO2. Synthesis gas is not the final product, requiring further conversion to liquid fuels by methanol or Fischer-Tropsch synthesis, which can account for some CO2 emissions. The conversion of CO2 in biogas to biomethane using electrolytic H2 represents an efficient CO2 valorisation pathway. This process enriches the product gas with CH4 through CO2 separation, which is subsequently transformed to yield additional CH4 and mitigate CO2 emissions. The production of CH4 is further incentivized by the possibility to enrich CH4 to concentrations that can enable the storage within the natural gas grid, which use to be highly accessible to most biogas treatment facilities. Additional reductions in CO2 emissions can be achieved by minimizing the number of process steps or by intensifying the processes. This is exemplified by the recently proposed integrated CO2 capture and methanation, which employs a single reactor. This review examines biogas upgrading technologies, encompassing both commercially mature solutions and emerging concepts. The evaluation of these technologies is conducted with a critical emphasis on achieving net-zero carbon emissions throughout the transformation process of biogas to the final product.
Research on the non-linguistic cognitive consequences of bilingualism remains inconclusive, with ongoing debate over which characteristics of bilinguals drive potential effects and which cognitive abilities may be involved. The impact of bilingualism and trilingualism on attentional performance was studied using a computerized Attentional Network Test. It was administered to 97 adults, assuming progressive improvement with increasing language experience. Reaction times and errors were examined across global and specific attentional network measures (alerting, orienting and executive control). Results indicated that the locus of improvement between bilinguals and trilinguals relative to monolinguals emerged primarily in global reaction times and errors, with no specific effects in any attentional network. Although differences between bilinguals and trilinguals showed only a non-significant trend, regression analyses revealed a significant logarithmic relationship whereby speaking more languages predicted faster global reaction times. The observed processing-speed improvement is discussed in relation to ongoing hypotheses proposing an adaptive response in multilinguals.
Early detection of Alzheimer’s disease (AD) is critical for effective intervention, yet current diagnostic methods are often invasive, costly, or inaccessible. Emerging research identifies sleep psychomotor disturbances as potential digital biomarkers for screening. However, deploying artificial intelligence (AI) in high-risk healthcare settings requires more than predictive performance; it demands transparency to ensure clinical trust and accountability. This research monitored the nocturnal psychomotor activity of 219 female participants (118 diagnosed with AD and 101 healthy controls) using wrist-worn inertial sensors. To bridge the gap between algorithmic accuracy and clinical interpretability, we employed X-ROCKET (Explainable Random Convolutional Kernel Transform). Unlike traditional black-box deep learning models, our proposed approach allows for the extraction of understandable features that validate the model’s decision-making process. Our results achieved a sensitivity (recall) of 88.16
Adult education in general, and literacy acquisition in particular, is often viewed as an empowering personal growth process. However, the extent to which basic literacy acquisition in adult life can be disempowering and induce devaluation and self-deprecation has remained under-explored. This study analyzes the reading and writing learning processes of a group of Moroccan migrant women in Spain. Using an ethnographic approach based on the observation of literacy classes and interviews with learners and teachers, the analysis focuses on the interrelation and coexistence of self-deprecation and self-enhancement as expressions of the ambivalences of the learning experience. These ambivalences are discussed considering the intersections of gender, education, and migration and in the context of the analysis of three forms of self-deprecating expressions: disclosure, infantilization, and humor.
In this work, we relate two recent constructions that generalize classical (genus-zero) polylogarithms to higher-genus Riemann surfaces. A flat connection valued in a freely generated Lie algebra on a punctured Riemann surface of arbitrary genus produces an infinite family of homotopy-invariant iterated integrals associated to all possible words in the alphabet of the Lie algebra generators. Each iterated integral associated to a word is a higher-genus polylogarithm. Different flat connections taking values in the same Lie algebra on a given Riemann surface may be related to one another by the composition of a gauge transformation and an automorphism of the Lie algebra, thus producing closely related families of polylogarithms. In this paper we provide two methods, which are inverses of one another, to explicitly relate in this way the meromorphic multiple-valued connection introduced by Enriquez in e-Print 1112.0864 and the non-meromorphic single-valued and modular-invariant connection introduced by D’Hoker, Hidding and Schlotterer, in e-Print 2306.08644.
