Centro de Documentación de las Artes Escénicas y de la Música
Secretaría de Estado de CulturaNot a member yet
3407326 research outputs found
Sort by
The effect of early diagenetic processes on the quantification of fossil micrometeorite abundance and flux in the geological record
No full textFossil micrometeorites (MMs) recovered from lithified sedimentary rocks, particularly iron‐rich (I‐type) cosmic spherules (CSs) provide valuable insights into past dust‐forming events. Their abundances, when combined with estimates of local sedimentation rates can be used to reconstruct the flux of extraterrestrial dust. However, their preservation in the geological record is highly susceptible to postdepositional diagenetic processes, complicating their quantification and past flux calculations. This study investigated lenticular calcitic concretions as potential sites of enhanced preservation of fossil MMs. A total of 17–18 I‐types (but no silicate dominated spherules, S‐types) were recovered from Cenomanian sediments within the Cretaceous Chalk Supergroup at Lulworth Cove, England. The I‐types, identified by optical and SEM–EDX analyses, exhibited typical dendritic textures and varying degrees of alteration, including mottled surfaces and loss of Ni and Cr by leaching. Calcitic concretions yielded a comparable concentration of I‐types to the surrounding hosting marl, but due to the added carbonate cementation during their growth, preservation per original sediment volume was shown to be enhanced (potentially by up to ~60%). Calcitic concretions can therefore act as microenvironments that enhance fossil MM preservation by limiting complete dissolution and loss of I‐types. To constrain possible diagenetic effects on fossil MM quantification, future studies should compare cosmic dust yields across multiple sites exposing the same targeted sedimentary horizon
National chemical societies and the formation of early global networks, ca. 1890-1914
No full textHistorians suggesting an early phase of globalisation in the decades before the First World War have pointed to new specialist learned societies as among the agents in the process. This paper explores the international dimensions of national chemical societies in this era of empires. During the nineteenth century, national chemical societies were established in many countries. Four of the earliest and largest – the [British] Chemical Society (founded 1841), the Société Chimique de France (1857), the Deutsche Chemische Gesellschaft (1867), and the American Chemical Society (1876) – recruited numerous members living abroad, so that, by the early twentieth century, such “extra-national” members – members, that is, who lived outside the state in which the society was based – constituted a substantial share of their memberships. Our paper examines this phenomenon. It argues that an analysis of extra-national members can help us chart the spread of chemistry around the globe. It considers whether the extra-national memberships of these chemical societies can be seen as constituting early, overlapping global networks of individuals, based on their common membership of leading societies
Impact of 2g of intrapartum azithromycin on the carriage and antibiotic resistance of <i>Escherichia coli</i> and <i>Klebsiella pneumoniae</i>
No full textTargeted interventions are urgently needed to reduce neonatal morbidity and mortality in sub-Saharan Africa (SSA). Intrapartum azithromycin has been explored to prevent maternal and neonatal sepsis, major contributors to this burden, but raises concerns about antibiotic resistance. At the start of this PhD, data on its impact on Escherichia coli and Klebsiella pneumoniae, leading causes of gram-negative neonatal sepsis were lacking. This thesis investigates the effect of intrapartum azithromycin on the carriage and antibiotic resistance of these bacteria.
The analysis conducted includes data from two randomized, double-blind, placebo-controlled trials (PregnAnZI) conducted in West Africa, where pregnant women were randomized (1:1) to receive either oral azithromycin (2g) or placebo. PregnAnZI-1, a proof-of-concept trial with 829 participants in The Gambia, evaluated the effect of intrapartum azithromycin on major gram-positive bacteria causing neonatal sepsis. PregnAnZI-2, a larger trial with approximately 12,000 participants in The Gambia and Burkina Faso, assessed its impact on neonatal sepsis and mortality.
In PregnAnZI-1, breast milk (BM), vaginal swabs (VS), and nasopharyngeal swabs (NPS) were collected from all mothers, and NPS from all newborns within 28 days of the intervention. In PregnAnZI-2, rectovaginal swabs (RVS), BM, and NPS were collected from 500 mothers, while rectal swabs (RS) and NPS were obtained from their infants within four months. Microbiological methods were used to identify isolates and perform antibiotic susceptibility testing for E. coli and K. pneumoniae in both PregnAnZI-1 and PregnAnZI-2. A subset of E. coli from maternal RVS and infant RS in PregnAnZI-2 was randomly selected for genomic analysis. Whole-genome sequencing (WGS) was performed to assess the impact of the intervention on antibiotic resistance genes and the genomic diversity of E. coli. In addition, discriminant analysis of principal components (DAPC) was applied to evaluate changes in genomic diversity associated with the intervention.
In PregnAnZI-1, microbiological analysis showed an increased prevalence of azithromycin-resistant E. coli in maternal VS and azithromycin-resistant K. pneumoniae in BM. However, there were no significant differences in bacterial carriage or antibiotic resistance among newborns. In PregnAnZI-2, the intervention primarily affected E. coli and K. pneumoniae in infants’ RS. E. coli carriage was lower in the azithromycin arm than in the placebo at days six and 28 post-intervention, but this was accompanied by a higher prevalence of azithromycin-resistant E. coli at these time points. The intervention also increased K. pneumoniae carriage at days six and 28 and azithromycin-resistant K. pneumoniae carriage at day 28. Notably, by the fourth month, the effect of the intervention on bacterial carriage and antibiotic resistance had waned, and there was no effect on maternal samples at any time point.
Genomic analysis showed that intrapartum azithromycin increased the carriage of macrolide resistance genes at day six post-intervention. The predominant resistance mechanism was macrolide inactivation via the plasmid-borne gene, mph(A). DAPC found minimal differences in E. coli diversity both pre- and post-intervention, as well as between the azithromycin and placebo arms. However, specific sequence types (ST’s), serotypes, and a phylogroup differed between arms post-intervention. ST349, serotype O153:H9, and phylogroup F were significantly more prevalent in the azithromycin arm, whereas ST101 and serotype O15:H18 were significantly lower in the azithromycin arm. These ST’s, serotypes, and phylogroup have been associated with antimicrobial resistance, virulence, and plasmid dissemination.
The increased carriage of K. pneumoniae, a multidrug-resistant pathogen, raises concerns about potential community transmission. Similarly, the higher prevalence of azithromycin-resistant E. coli suggests the intervention may contribute to the spread of antibiotic resistance, reinforced by the increased detection of plasmid-mediated macrolide resistance genes in the azithromycin arm. Furthermore, the intervention influenced the proliferation of specific ST’s, serotypes, and a phylogroup associated with antimicrobial resistance (AMR), and may potentially promote the establishment of resistant clones, an area requiring further investigation.
This PhD research highlights the impact of intrapartum azithromycin on E. coli and K. pneumoniae and its findings should be considered alongside the overall benefits of intrapartum azithromycin. This is crucial in assessing its suitability for routine implementation in high-burden settings. Additionally, ongoing surveillance should be an integral component of this intervention to monitor its long-term effects on E. coli and K. pneumoniae
ExoClock Project. IV. A Homogeneous Catalog of 620 Updated Exoplanet Ephemerides
No full textThe ExoClock project is an open platform aiming to monitor exoplanets by integrating observations from space- and ground-based telescopes. This study presents an updated catalog of 620 exoplanet ephemerides, integrating 30,000 measurements from ground-based telescopes (the ExoClock network), literature, and space telescopes (Kepler, K2 and TESS). The updated catalog includes 277 planets from TESS which require special observing strategies due to their shallow transits or bright host stars. This study demonstrates that data from larger telescopes, and the employment of new methodologies such as synchronous observations with small telescopes, are capable of monitoring special cases of planets. The new ephemerides show that 45% of the planets required an update while the results show an improvement of 1 order of magnitude in prediction uncertainty. The collective analysis also enabled the identification of new planets showing transit-timing variations, highlighting the importance of extensive observing coverage. Developed in the context of the ESA’s Ariel space mission, with the goal of delivering a catalog with reliable ephemerides to increase the mission efficiency, ExoClock’s scope and service have grown well beyond the remit of Ariel. The ExoClock project has been operating in the framework of open science, and all tools and products are accessible to everyone within academia and beyond, to support efficient scheduling of future exoplanet observations, especially from larger telescopes where the pressure for time allocation efficiency is higher (Ariel, JWST, VLT, ELT, Subaru etc.). The inclusion of diverse audiences in the process and the collaborative mode not only foster democratization of science but also enhance the quality of the results
The potential for a transdisciplinary systems approach to improve national policy analysis: learning from UK cases of home energy transitions
No full textThe urgent imperative to decarbonise societies requries effective decisions to neogotiate interconnections of people, technology and policies. In this theory paper, we hypothesise that integrating transdisciplinary engineering with systems approaches can provide useful principles and tools to support effective sustainability policymaking. We consider this hypothesis in the context of a historic and current UK energy sector transition: (a) the transition from ‘town-gas’ to natural gas in the 1960–1970s and (b) the current shift from natural gas to low carbon domestic heating, focussing on heat pump deployment. Through these casestudies, we find that transdisciplinary and systems approaches are apparent in the successful historic transition, while remaining largely absent in the present low carbon heating transition, which is currently stalled. We argue this is caused by policy analysis being siloed and economically focused. We present two systems approach examples to show how they might be applied to begin addressing current UK policy failures for low carbon heating. We identify benefits while recognising some key limitations of this approach, including the resource requirements on officials. The paper concludes with suggestions for further research to continue developing the conceptual and practical basis and therefore lead to improved decision making in national sustainability policymaking
An investigation into the breadth of learning objectives developed in STEM online laboratories
No full textOnline laboratories have gained a great deal of interest in recent years with benefits including reduced costs, support for increasing student numbers, increased flexibility and accessibility to practical work for students attending distance learning courses or with physical disabilities. However, designing teaching and learning activities for online laboratories introduces new challenges because many learning aspects that are inherent in conventional laboratories (e.g. safety, ethics, motor skills etc.) must be explicitly designed into online laboratories. This research aims to assist educators to design Science, Technology, Engineering and Mathematics (STEM) online laboratories that develop a broad range of learning objectives to meet students’ educational needs.
In this paper a framework for STEM online laboratory learning objectives is introduced, building on previous approaches in the literature. The framework provides a structured approach to help course designers and educational technologists to design and assess the learning objectives and design characteristics of online experiments. The framework was used to map 23 online laboratories at a large distance learning university, and the results identified some trends and gaps in learning objective coverage. The results highlight the importance of defining the full breadth of learning objectives for online experiments at the design stage to ensure that the experiment is appropriately designed to allow students to achieve the desired learning outcomes. Furthermore, different online experiment designs are appropriate to different learning objectives, so care must be taken to select the most appropriate delivery mechanism for the online laboratory.
It is proposed that the framework could be used by educators to support the design of new online laboratories as well as evaluating the laboratory learning objectives coverage in existing online laboratories
Petrography, geochronology, and volatile inventory of lunar meteorite Northwest Africa 12593
No full textThe petrography and geochemistry of Northwest Africa (NWA) 12593 reveals association with the ferroan anorthosite and magnesian suites, as well as highlands-type clasts that are compositionally distinct from Apollo highlands material, re-affirming previous observations of increased compositional diversity in lunar crustal rocks outside of the Apollo sampled region. A large number of apatite grains were identified in lunar meteorite NWA 12593, in texturally pristine condition and associated with lithic clasts and the impact melt matrix. Chlorine and hydrogen isotope compositions obtained on apatite in NWA 12593 (δ 37 Cl = + 11.3 ‰ to + 53.1 ‰; δD = − 368 ‰ to + 1030 ‰) are significantly greater than in Apollo samples and basaltic lunar meteorites, with a broad range of volatile abundances spanning two orders of magnitude (Cl = 1053-12337 ppm; H2O = 143-4486 ppm). These volatile signatures reveal new insights into the distribution and isotopic heterogeneity of highly volatile elements in areas of the lunar surface not sampled previously and indicate that the lunar interior may have been equally heterogenous throughout its evolution. The variety of impact melt and lithic material in this sample implies a complex impact history that can contribute to future lunar exploration (e.g., Artemis III) surface activity goals of determining the lunar record of Inner Solar System impact history and volatile distribution throughout the lunar surface and interior
Reimaging the Heart in the Home During the COVID-19 Pandemic: The Importance of the Built Environment for Young Adults Living with Life-Limiting or Life-Threatening Conditions and Family Members from a UK Perspective.
No full textConveni de col·laboració entre l'Ajuntament de Barcelona i el World Ocean Council (WOC) per al suport a la ubicació de la seu del WOC a Barcelona així com activitats relacionades en el marc de l'impuls a l'economia blava a la ciutat de Barcelona.
No full textAprovat per les institucions signants el 07-04-202