Significance The formation of the Isthmus of Panama, which linked North and South America, is key to understanding the biodiversity, oceanography, atmosphere, and climate in the region. Despite its importance across multiple disciplines, the timing of formation and emergence of the Isthmus and the biological patterns it created have been controversial. Here, we analyze molecular and fossil data, including terrestrial and marine organisms, to show that biotic migrations across the Isthmus of Panama began several million years earlier than commonly assumed. An earlier evolution of the Isthmus has broad implications for the mechanisms driving global climate (e.g., Pleistocene glaciations, thermohaline circulation) as well as the rich biodiversity of the Americas. The linking of North and South America by the Isthmus of Panama had major impacts on global climate, oceanic and atmospheric currents, and biodiversity, yet the timing of this critical event remains contentious. The Isthmus is traditionally understood to have fully closed by ca. 3.5 million years ago (Ma), and this date has been used as a benchmark for oceanographic, climatic, and evolutionary research, but recent evidence suggests a more complex geological formation. Here, we analyze both molecular and fossil data to evaluate the tempo of biotic exchange across the Americas in light of geological evidence. We demonstrate significant waves of dispersal of terrestrial organisms at approximately ca. 20 and 6 Ma and corresponding events separating marine organisms in the Atlantic and Pacific oceans at ca. 23 and 7 Ma. The direction of dispersal and their rates were symmetrical until the last ca. 6 Ma, when northern migration of South American lineages increased significantly. Variability among taxa in their timing of dispersal or vicariance across the Isthmus is not explained by the ecological factors tested in these analyses, including biome type, dispersal ability, and elevation preference. Migration was therefore not generally regulated by intrinsic traits but more likely reflects the presence of emergent terrain several millions of years earlier than commonly assumed. These results indicate that the dramatic biotic turnover associated with the Great American Biotic Interchange was a long and complex process that began as early as the Oligocene–Miocene transition.
We introduced a multimodal foundational model for financial transactions that integrates both structured attributes and unstructured textual descriptions into a unified representation. By adapting masked language modeling to transaction sequences, we demonstrated that our approach not only outperforms classical feature engineering and discrete event sequence methods but is also particularly effective in data-scarce Open Banking scenarios. To our knowledge, this is the first large-scale study across thousands of financial institutions in North America, providing evidence that multimodal representations can generalize across geographies and institutions. These results highlight the potential of self-supervised models to advance financial applications ranging from fraud prevention and credit risk to customer insights
Carmen Cabrera, Miguel González-Leonardo, Andrea Nasuto
et al.
Urban mobility is central to economic activity, social inclusion, and access to essential services. COVID-19 caused disruptions to mobility globally, yet its long-term impacts in less developed countries remain poorly understood. Using over 170 million anonymised mobile phone records from Meta-Facebook users in Argentina, Chile, and Colombia (March 2020 to May 2022), we find sustained changes in mobility across socioeconomic and rural-urban gradients. We reveal that mobility recorded the sharpest declines and remained below pre-pandemic levels in most high-density and low socio-economic deprivation areas, while low-density and more deprived communities returned to baseline. These differences reflect the scale of the initial mobility shock rather than subsequent recovery rates. Net mobility to urban cores remained consistently below pre-pandemic levels, suggesting a shift in their functional role. By revealing how COVID-19 reinforced mobility-related inequalities, we contribute novel evidence for planners and policymakers seeking to build more inclusive and resilient mobility systems.
Protagonistas de nuevos mecanismos de suministro de mano de obra barata, la mayoría de los aprendices de oficio en la Cuba del siglo XIX vivió una realidad influida negativamente por la esclavitud, mientras crecía la demanda de fuerza de trabajo en las plantaciones. La servidumbre por contrato fue absorbida por la esclavitud. El hecho de que la esclavitud africana alcanzara en ese siglo su punto álgido en la colonia española interfirió en la visión y las actuaciones de las autoridades de la isla sobre el sistema de aprendizaje de artes y oficios. Este artículo se propone, con fuentes hemerográficas y de archivo, tratar las limitaciones de dicho sistema y cubrir las razones del afán institucional por incentivar, en una aparente inclusión, la participación y acreditación de los artesanos de color en la vida urbana. La investigación concluye que los aprendices esclavizados, cuando eran "negros" o mediaba de algún modo la variable de color, no se distinguían de los aprendices afrodescendientes de condición libre.
Juan Pablo Hurtado-Gómez, Juan M. Daza, Mario Vargas-Ramírez
et al.
The genus Helicops Wagler, 1828 comprises 20 species of semiaquatic snakes. It is mostly distributed in the cis-Andean region of South America, with only two trans-Andean species (H. danieli, H. scalaris). Helicops danieli is endemic to Colombia and occurs through most of the trans-Andean region. Herein two mitochondrial and two nuclear genomic markers were sequenced for 16 samples of H. danieli across most of its distribution range to understand its phylogeography. A dated tree was also generated with additional sequences from previous studies to infer the divergence times between H. danieli and its cis-Andean congeners and of lineages within H. danieli. Using previously published data, ancestral states were estimated for putative phenotypic synapomorphies for the major clades of Helicops. For H. danieli, four clades corresponding to the main river basins within its distribution were recovered. Our dated tree suggests that the ancestor of H. danieli diverged from its closest congeners in the late Miocene (8.7 Mya), which can be associated with the closure of the Andalucia Pass, south of the Eastern Cordillera. Divergence within H. danieli commenced 1.1 Mya. Within the genus Helicops, two distinct hemipenial morphologies were observed, which are suggested as putative synapomorphies for the two most basal clades. Recognition of these two clades as distinct subgenera, Helicops sensu stricto and Tachynectes Fitzinger, 1843 is proposed. For the junior homonym Tachynectes von der Mark, 1863, rarely applied to fossil fishes, the replacement name Ichthyotachynectes nom. nov. is introduced. Furthermore, the evolution of another four phenotypic traits in Helicops and their phylogenetic utility are discussed.
The current dominant approach for neural speech enhancement is via purely-supervised deep learning on simulated pairs of far-field noisy-reverberant speech (i.e., mixtures) and clean speech. The trained models, however, often exhibit limited generalizability to real-recorded mixtures. To deal with this, this paper investigates training enhancement models directly on real mixtures. However, a major difficulty challenging this approach is that, since the clean speech of real mixtures is unavailable, there lacks a good supervision for real mixtures. In this context, assuming that a training set consisting of real-recorded pairs of close-talk and far-field mixtures is available, we propose to address this difficulty via close-talk speech enhancement, where an enhancement model is first trained on simulated mixtures to enhance real-recorded close-talk mixtures and the estimated close-talk speech can then be utilized as a supervision (i.e., pseudo-label) for training far-field speech enhancement models directly on the paired real-recorded far-field mixtures. We name the proposed system ctPuLSE. Evaluation results on the popular CHiME-4 dataset show that ctPuLSE can derive high-quality pseudo-labels and yield far-field speech enhancement models with strong generalizability to real data.
L. Francisco Letelier Troncoso, Juan Pablo Paredes, Victor Fernández González
et al.
Este artículo compara dos procesos comunitarios vecinales que han tenido lugar en una ciudad intermedia de la zona central de Chile. El primero de ellos tuvo lugar antes del estallido social de 2019 y el segundo se originó a partir de este. En ambos casos se observan articulaciones y vínculos que, por un lado, traspasan los límites político-administrativos establecidos por la forma dominante de concebir lo vecinal y, por otro complejizan las agendas comunitarias. Sin embargo, existe entre ellos diferencias importantes. En el primero, pre estallido, se aprecia un proceso estado-céntrico: los esfuerzos de la articulación se orientan a la búsqueda de respuesta del estado. En el segundo, originado a partir del estallido, el proceso es más bien socio-céntrico: los esfuerzos apuntan a fortalecer las propias redes comunitarias y su autonomía. Este proceso, socio-céntrico, reticular y performático, da pistas para pensar lo vecinal. Si bien las experiencias que habíamos estudiado antes muestran un incremento del poder de las organizaciones para intermediar, este sigue estando sujeto a las formas estatales de gestionar lo social. En cambio, aquí aparece lo comunitario como esfera autónoma: no existe para dirigirse al estado, sino que para reproducirse a sí mismo.
Background Disturbed sleep is common among people living with dementia and their informal caregivers, and is associated with negative health outcomes. Dyadic, multi-modal interventions targeting caregiver and care-recipient sleep have been recommended yet remain limited. This protocol details the development of a single-arm feasibility trial of a multi-modal, therapist-led, six-week intervention targeting sleep disturbance in dyads of people living with dementia and their primary caregiver. Methods We aim to recruit 24 co-residing, community-dwelling dyads of people living with dementia and their primary informal caregiver (n = 48) with sleep concerns (Pittsburgh Sleep Quality Index ≥5 for caregivers, and caregiver-endorsed sleep concerns for the person living with dementia). People who live in residential care settings, are employed in night shift work, or are diagnosed with current, severe mental health conditions or narcolepsy, will be excluded. Participants will wear an actigraph and complete sleep diaries for two weeks prior, and during the last two weeks, of active intervention. The intervention is therapist-led and includes a mix of weekly small group video sessions and personalised, dyadic sessions (up to 90 min each) over six weeks. Sessions are supported by a 37-page workbook offering strategies and spaces for reflections/notes. Primary feasibility outcomes are caregiver: session attendance, attrition, and self-reported project satisfaction. Secondary outcomes include dyadic self-reported and objectively-assessed sleep, depression and anxiety symptoms, quality of life, and social support. Self-report outcomes will be assessed at pre- and post-intervention. Discussion If feasible, this intervention could be tested in a larger randomised controlled trial to investigate its efficacy, and, upon further testing, may potentially represent a non-pharmacological approach to reduce sleep disturbance among people living with dementia and their caregivers. ANZCTR Trial registration ACTRN12622000144718: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=382960&showOriginal=true&isReview=true
Remittances have become one of the driving forces of development for countries all over the world, especially in lower-middle-income nations. This paper empirically investigates the association between remittance flows and financial development in 4 lower-middle-income countries of Latin America. By using a panel data set from 1996 to 2019, the study revealed that remittances and financial development are positively associated in these countries. The study also discovered that foreign direct investment and inflation were positively correlated with financial development while trade openness had a negative association with financial development. Therefore, policymakers of these countries should implement and formulate such policies so that migrant workers would have the incentives to send money through formal channels, which will augment the effect of remittances on the recipient country.
Matthew Combs, Ashley L. Marcinkiewicz, Alan P. Dupuis
et al.
ABSTRACT Host association—the selective adaptation of pathogens to specific host species—evolves through constant interactions between host and pathogens, leaving a lot yet to be discovered on immunological mechanisms and genomic determinants. The causative agents of Lyme disease (LD) are spirochete bacteria composed of multiple species of the Borrelia burgdorferi sensu lato complex, including B. burgdorferi (Bb), the main LD pathogen in North America—a useful model for the study of mechanisms underlying host-pathogen association. Host adaptation requires pathogens’ ability to evade host immune responses, such as complement, the first-line innate immune defense mechanism. We tested the hypothesis that different host-adapted phenotypes among Bb strains are linked to polymorphic loci that confer complement evasion traits in a host-specific manner. We first examined the survivability of 20 Bb strains in sera in vitro and/or bloodstream and tissues in vivo from rodent and avian LD models. Three groups of complement-dependent host-association phenotypes emerged. We analyzed complement-evasion genes, identified a priori among all strains and sequenced and compared genomes for individual strains representing each phenotype. The evolutionary history of ospC loci is correlated with host-specific complement-evasion phenotypes, while comparative genomics suggests that several gene families and loci are potentially involved in host association. This multidisciplinary work provides novel insights into the functional evolution of host-adapted phenotypes, building a foundation for further investigation of the immunological and genomic determinants of host association. IMPORTANCE Host association is the phenotype that is commonly found in many pathogens that preferential survive in particular hosts. The Lyme disease (LD)-causing agent, B. burgdorferi (Bb), is an ideal model to study host association, as Bb is mainly maintained in nature through rodent and avian hosts. A widespread yet untested concept posits that host association in Bb strains is linked to Bb functional genetic variation conferring evasion to complement, an innate defense mechanism in vertebrate sera. Here, we tested this concept by grouping 20 Bb strains into three complement-dependent host-association phenotypes based on their survivability in sera and/or bloodstream and distal tissues in rodent and avian LD models. Phylogenomic analysis of these strains further correlated several gene families and loci, including ospC, with host-specific complement-evasion phenotypes. Such multifaceted studies thus pave the road to further identify the determinants of host association, providing mechanistic insights into host-pathogen interaction.
Las ideas en torno a la universidad y a la sociedad expuestas por Raúl Roa García en sus textos constituyen una vívida narración del contexto histórico. Procesos como el auge de los movimientos estudiantiles en América Latina y La Habana, su pertenencia y accionar dentro de la Generación del 30, su papel como profesor y decano de la Facultad de Ciencias Sociales y Derecho Público y el apogeo del gansterismo en la colina a partir de 1948 determinaron sus concepciones acerca del estudiantado universitario. La idea
medular en los escritos consultados es la concepción de la universidad como ente que provee una utilidad social y que está obligada a inmiscuirse en los problemas de la sociedad. Por ello, es una institución que debe de estar a la altura de su tiempo y contribuir a la construcción de la nación. También, destaca la exaltación de los valores morales que deben distinguir a los hombres a través de un examen de conciencia oportuno.
This preprint describes work in progress on LR-Sum, a new permissively-licensed dataset created with the goal of enabling further research in automatic summarization for less-resourced languages. LR-Sum contains human-written summaries for 40 languages, many of which are less-resourced. We describe our process for extracting and filtering the dataset from the Multilingual Open Text corpus (Palen-Michel et al., 2022). The source data is public domain newswire collected from from Voice of America websites, and LR-Sum is released under a Creative Commons license (CC BY 4.0), making it one of the most openly-licensed multilingual summarization datasets. We describe how we plan to use the data for modeling experiments and discuss limitations of the dataset.
The Wigner-Smith (WS) time delay matrix relates an acoustic system's scattering matrix to its wavenumber derivative. The entries of the WS time delay matrix can be expressed in terms of energy density-like volume integrals, which cannot be efficiently evaluated in a boundary element method framework. This paper presents two schemes for efficiently populating the WS time delay matrix. The direct formulation casts the energy density-like volume integrals into integrals of the incident field and the field and/or its normal derivative over the scatterer surface. The indirect formulation computes the system's scattering matrix and its wavenumber derivative, again via surface integration, and then invokes the WS relationship to compute the WS time delay matrix. Both the direct and the indirect formulations yield equivalent results and can be easily integrated into standard boundary element codes.