A single sub-km Kuiper Belt object from a stellar Occultation in archival data

The Kuiper belt is a remnant of the primordial Solar System. Measurements of its size distribution constrain its accretion and collisional history, and the importance of material strength of Kuiper belt objects (KBOs). Small, sub-km sized, KBOs elude direct detection, but the signature of their occultations of background stars should be detectable. Observations at both optical and X-ray wavelengths claim to have detected such occultations, but their implied KBO abundances are inconsistent with each other and far exceed theoretical expectations. Here, we report an analysis of archival data that reveals an occultation by a body with a 500 m radius at a distance of 45 AU. The probability of this event to occur due to random statistical fluctuations within our data set is about 2%. Our survey yields a surface density of KBOs with radii larger than 250 m of 2.1^{+4.8}_{-1.7} x 10^7 deg^{-2}, ruling out inferred surface densities from previous claimed detections by more than 5 sigma. The fact that we detected only one event, firmly shows a deficit of sub-km sized KBOs compared to a population extrapolated from objects with r>50 km. This implies that sub-km sized KBOs are undergoing collisional erosion, just like debris disks observed around other stars.Comment: To appear in Nature on December 17, 2009. Under press embargo until 1800 hours London time on 16 December. 19 pages; 7 figure

The Documentation of Chedungun and the Pewenche Highlands: Phase One

This article provides a descriptive guide to the documentation of Chedungun, the regional variant of Mapudungun (ISO 639-2 code arn) that is spoken by the Pewenche people. The 15-hour documentation is currently deposited in the Endangered Language Archive (ELAR) and corresponds to Phase One of a long-term initiative that is currently progressing to a postdoctoral project (Phase Two). Both phases are supported and funded by the Endangered Languages Documentation Programme. Since the objective of the project is to document the endangered migratory lifestyle and language of the Pewenche people, we will reflect on how the territorial inaccessibility imposed by the COVID-19 pandemic challenged the project’s elemental strategy, which relied on several documentary journeys to the lands that are seasonally occupied by the Pewenche during the summer for transhumance purposes. We will show why the collaborative workflow sustained by self-documentation practices evolved from an auxiliary tool to a regular and essential element of the team’s current and future projects

The emerging structure of the Extended Evolutionary Synthesis: where does Evo-Devo fit in?

The Extended Evolutionary Synthesis (EES) debate is gaining ground in contemporary evolutionary biology. In parallel, a number of philosophical standpoints have emerged in an attempt to clarify what exactly is represented by the EES. For Massimo Pigliucci, we are in the wake of the newest instantiation of a persisting Kuhnian paradigm; in contrast, Telmo Pievani has contended that the transition to an EES could be best represented as a progressive reformation of a prior Lakatosian scientific research program, with the extension of its Neo-Darwinian core and the addition of a brand-new protective belt of assumptions and auxiliary hypotheses. Here, we argue that those philosophical vantage points are not the only ways to interpret what current proposals to ‘extend’ the Modern Synthesis-derived ‘standard evolutionary theory’ (SET) entail in terms of theoretical change in evolutionary biology. We specifically propose the image of the emergent EES as a vast network of models and interweaved representations that, instantiated in diverse practices, are connected and related in multiple ways. Under that assumption, the EES could be articulated around a paraconsistent network of evolutionary theories (including some elements of the SET), as well as models, practices and representation systems of contemporary evolutionary biology, with edges and nodes that change their position and centrality as a consequence of the co-construction and stabilization of facts and historical discussions revolving around the epistemic goals of this area of the life sciences. We then critically examine the purported structure of the EES—published by Laland and collaborators in 2015—in light of our own network-based proposal. Finally, we consider which epistemic units of Evo-Devo are present or still missing from the EES, in preparation for further analyses of the topic of explanatory integration in this conceptual framework

El Uroselectan en la Urología Infantil: resumen

Presented at the session of August 20, 1930Presentado en la sesión de 20 de agosto de 1930

An overview of sustainable entrepreneurship in tourism, destination, and hospitality research based on the Web of Science

Sustainability, entrepreneurship and tourism, destination and hospitality research have attracted scholars’ attention for their relevance in bringing to fruition a future that links economic well-being with the environmental, cultural, and social sustainability of human beings. This article provides a bibliometric overview of the academic research where these topics intersect. To accomplish this, various bibliometric methods are implemented, which include a performance analysis and graphic mapping of the academic production in this specific topic. This research uses the Web of Science database to identify and classify the most preponderant investigations in the field and considers articles, authors, institutions, countries, and journals. To complete the performance analysis, a series of indicators, such as number of papers and number of citations, are used. Graphic visualization maps are produced using the co-citation and co-occurrence of keywords under the Visualization of Similarities—VOSviewer—software. The results show a growing concern for entrepreneurship in sustainable tourism development research, which is evidenced in the increasing number of studies during the last decade. Some influential research institutions and authors from countries including the USA, New Zealand, and Norway are found to be influential leaders in this topic. Additionally, the results show that journals from the area of hospitality, leisure, sport, and tourism are frontrunners in this subject

Hierarchy Theory of Evolution and the Extended Evolutionary Synthesis: Some Epistemic Bridges, Some Conceptual Rifts

Contemporary evolutionary biology comprises a plural landscape of multiple co-existent conceptual frameworks and strenuous voices that disagree on the nature and scope of evolutionary theory. Since the mid-eighties, some of these conceptual frameworks have denounced the ontologies of the Modern Synthesis and of the updated Standard Theory of Evolution as unfinished or even flawed. In this paper, we analyze and compare two of those conceptual frameworks, namely Niles Eldredge’s Hierarchy Theory of Evolution (with its extended ontology of evolutionary entities) and the Extended Evolutionary Synthesis (with its proposal of an extended ontology of evolutionary processes), in an attempt to map some epistemic bridges (e.g. compatible views of causation; niche construction) and some conceptual rifts (e.g. extra-genetic inheritance; different perspectives on macroevolution; contrasting standpoints held in the “externalism–internalism” debate) that exist between them. This paper seeks to encourage theoretical, philosophical and historiographical discussions about pluralism or the possible unification of contemporary evolutionary biology

Design and Implementation of a Modular Multilevel Series-Parallel Converter for Second-Life Battery Energy Storage Systems

Battery Energy Storage Systems (BESS) offer scalable energy storage solutions, especially valuable for remote, off-grid applications. However, traditional battery packs with fixed series-parallel configurations lack reconfigurability and are limited by the weakest cell, hindering their application for second-life batteries. The Modular Multilevel Series-Parallel Converter (MMSPC) addresses these limitations by enabling dynamic reconfiguration, optimizing cell balancing, and enhancing energy control. This paper experimentally evaluates a single-phase BESS based on the MMSPC with an output power equivalent to 2 kW and two battery units (155V), demonstrating stable output and reduced internal losses across varied battery parameters

Shared midgut binding sites for Cry1A.105, Cry1Aa, Cry1Ab, Cry1Ac and Cry1Fa proteins from Bacillus thuringiensis in two important corn pests, Ostrinia nubilalis and Spodoptera frugiperda

First generation of insect-protected transgenic corn (Bt-corn) was based on the expression of Cry1Ab or Cry1Fa proteins. Currently, the trend is the combination of two or more genes expressing proteins that bind to different targets. In addition to broadening the spectrum of action, this strategy helps to delay the evolution of resistance in exposed insect populations. One of such examples is the combination of Cry1A.105 with Cry1Fa and Cry2Ab to control O. nubilalis and S. frugiperda. Cry1A.105 is a chimeric protein with domains I and II and the C-terminal half of the protein from Cry1Ac, and domain III almost identical to Cry1Fa. The aim of the present study was to determine whether the chimeric Cry1A.105 has shared binding sites either with Cry1A proteins, with Cry1Fa, or with both, in O. nubilalis and in S. frugiperda. Brush-border membrane vesicles (BBMV) from last instar larval midguts were used in competition binding assays with 125I-labeled Cry1A.105, Cry1Ab, and Cry1Fa, and unlabeled Cry1A.105, Cry1Aa, Cry1Ab, Cry1Ac, Cry1Fa, Cry2Ab and Cry2Ae. The results showed that Cry1A.105, Cry1Ab, Cry1Ac and Cry1Fa competed with high affinity for the same binding sites in both insect species. However, Cry2Ab and Cry2Ae did not compete for the binding sites of Cry1 proteins. Therefore, according to our results, the development of cross-resistance among Cry1Ab/Ac, Cry1A.105, and Cry1Fa proteins is possible in these two insect species if the alteration of shared binding sites occurs. Conversely, cross-resistance between these proteins and Cry2A proteins is very unlikely in such case

Critical and prospective analysis of online education in pandemic and post-pandemic contexts: Digital tools and resources to support teaching in synchronous and asynchronous learning modalities

Humanity, prior to the COVID-19 pandemic, was already in the process of a gradual cultural transition between modernity and postmodernity. The rapid pace of scientific and technological advances has led humans towards a progressive adaptation, as they develop new ways to confront and to solve their problems. In the exceptional context of the pandemic, people and institutions have faced a sudden need to readapt their ways of life and their means of communication. In education, the need to migrate from traditional classrooms to online systems was urgent, and the shift required digital tools and resources to support teaching. This theoretical article aims to analyze the disruption in the educational context and to detail the adaptations that may contribute to the effectiveness of educational processes. Moreover, it discusses the pedagogical, methodological, didactic, and evaluative aspects of the change in education. The article also proposes some guidelines for learning on both synchronous and asynchronous platforms. The trends associated with these changes are analyzed in order to offer a perspective on education in the post-pandemic world