Representations of the fundamental group of a surface in PU(p,q) and holomorphic triples

We count the connected components in the moduli space of PU(p,q)-representations of the fundamental group for a closed oriented surface. The components are labelled by pairs of integers which arise as topological invariants of the flat bundles associated to the representations. Our results show that for each allowed value of these invariants, which are bounded by a Milnor-Wood type inequality, there is a unique non-empty connected component. Interpreting the moduli space of representations as a moduli space of Higgs bundles, we take a Morse theoretic approach using a certain smooth proper function on the Higgs moduli space. A key step is the identification of the function's local minima as moduli spaces of holomorphic triples. We prove that these moduli spaces of triples are non-empty and irreducible.Comment: 6 pages, to appear in C. R. Acad. Sci. Paris Ser. I Mat

Associations of Vitamin D Levels with Physical Fitness and Motor Performance; A Cross-Sectional Study in Youth Soccer Players from Southern Croatia

Simple Summary Vitamin D is a fat-soluble prohormone crucial for bone mineralization, muscle contractility, and neurological conductivity. It is theorized that Vitamin D plays an important role in sport performances, especially in young athletes. In this study we examined the associations of levels of 25-hydroxyvitamin D (25(OH)D) with physical fitness and motor-performance achievements in youth soccer players from Southern Croatia. Participants were tested on physical fitness, motor performance and vitamin D at the end of the winter period, when levels of vitamin D are known to be lowest due to low exposure to sunlight. Results showed that deficiency of 25(OH)D was widespread among youth soccer players living in Southern Croatia. Low 25(OH)D levels were associated with lower results in fitness tests (i.e., tests of energetic capacities), but there was no correlation between 25(OH)D levels and the results in motor performance tests (i.e., skill tests). Our results support the theory of the association between vitamin D and energetic capacities of athletes, but there is no evidence on association between vitamin D and skill-based capacities. Vitamin D level is known to be a factor potentially influencing physical fitness, but few studies have examined this phenomenon among youth athletes. We aimed to evaluate the associations of vitamin D levels (as measured by 25-hydroxyvitamin D concentrations-25(OH)D) with various physical fitness and motor performance tests in youth football (soccer) players. This cross-sectional study included a total of 52 youth soccer players (15.98 +/- 2.26 years old) from Southern Croatia. The participants were evaluated at the end of the winter period and data were collected of anthropometric measures (body mass and body height), vitamin D status (25(OH)D levels), physical fitness tests (sprints of 10 and 20 m, 20 yards test, the countermovement jump, the reactive strength index (RSI)) and motor performance tests (the soccer-specific CODS, the soccer-specific agility, and static balance). Among the studied players, 54% had 25(OH)D insufficiency/deficiency, showing a lack of 25(OH)D is widespread even in youth athletes living at a southern latitude. The 25(OH)D level was correlated with sprint 20 m, 20 yards tests, and RSI, showing a greater role of 25(OH)D in physical fitness tests where energetic capacity is essential than in sport-related motor performance tests where skills are crucial. Our results support the idea that vitamin D can play a determinant role in physical fitness tests with a clear physiological component, but is not crucial in motor performance tests related to specific sports where skills are a key component. Future studies should investigate the effects of vitamin D supplementation on the performance in physical fitness and motor performance tests among youth athletes.This research is partially financed by Croatian Science Foundation (grant numbers: IP2018-01-8330; DOK-2018-09-1940)

ENSAMBLES DE AVES DE LOS BOSQUES ENDEMICOS DE POLYLEPIS PACENSIS EN BOLIVIA

Resumen ∙ Los bosques de Polylepis pacensis son endémicos de Bolivia y se distribuyen en los departamentos de La Paz (inmediaciones al nevado Illimani, Quime e Inquisivi) y Cochabamba (Cotacajes). En este estudio, se evaluó el ensamble de aves en cuatro fragmentos de bosque de P. pacensis ubicados en las faldas del nevado Illimani, La Paz, Bolivia. En estos fragmentos de bosque se observaron 31 especies de aves, incluyendo dos especies endémicas de Bolivia, Colibrí Negrito (Aglaeactis pamela) y Pinchaflor Carbonero (Diglossa carbonaria), y dos especies fuertemente especializadas a bosques de Polylepis, Tijeral de Yánac (Leptasthenura yanacensis) y Conirrostro Gigante (Conirostrum binghami). Los bosques de Polylepis pacensis están altamente amenazados por actividades humanas como quema, extracción de leña y agricultura; las cuales podrían estar causando la deforestación y degradación de este importante hábitat para las aves. Es crucial implementar programas de conservación que incluyan la participación activa de la población local.Abstract ∙ Bird assemblages in endemic Polylepis pacensis woodlands in Bolivia Polylepis pacensis woodlands are endemic to Bolivia, distributed in La Paz (near Illimani, Quime, and Inquisivi) and Cochabamba (Cotacajes) departments. In this study, we evaluated the bird assemblages of four fragments of P. pacensis woodlands located in the foothills of nevado Illimani, La Paz, Bolivia. In these woodlands, we recorded 31 bird species, including two endemic species of Bolivia, Black-hooded Sunbeam (Aglaeactis pamela) and Grey-bellied Flowerpiercer (Diglossa carbonaria), and two species strongly specialized to Polylepis woodlands, Tawny Tit-spinetail (Leptasthenura yanacensis) and Giant Conebill (Conirostrum binghami). Polylepis pacensis woodlands are highly threatened by human activities, such as burning, logging and agriculture; which may be causing of deforestation and degradation of this important habitat for bird species. It is crucial to implement conservation programs involving the active participation of local people

Laboratory medicine in pandemic of COVID-19

After the outbreak in China in the year 2019, severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) quickly spread around the world causing a protracted pandemic. Approximately one-third of infections appear to be asymptomatic. Symptomatic disease is characterized primarily by symptoms of respiratory tract infection of varying severity. But Coronavirus Disease 2019 (COVID-19) is much more than an acute respiratory disease because SARS-CoV-2 affects many organs inducing a vast number of symptoms such as cardiovascular, neurological, gastrointestinal, dermatological, with numerous complications. Short and long-term effects of infection, severe ones, and especially mild forms of the disease which affect a huge number of patients need to be further investigated. Laboratory medicine has a crucial role in early diagnosis of the disease, recognition of the patients who need hospital care, and close monitoring of hospitalized patients to timely identify associated clinical complications as well as follow-up of patients with long-term COVID-19

Cutmarked bone of drought-tolerant extinct megafauna deposited with traces of fire, human foraging, and introduced animals in SW Madagascar

People could have hunted Madagascar’s megafauna to extinction, particularly when introduced taxa and drought exacerbated the effects of predation. However, such explanations are difficult to test due to the scarcity of individual sites with unambiguous traces of humans, introduced taxa, and endemic megaherbivores. We excavated three coastal ponds in arid SW Madagascar and present a unique combination of traces of human activity (modified pygmy hippo bone, processed estuarine shell and fish bone, and charcoal), along with bones of extinct megafauna (giant tortoises, pygmy hippos, and elephant birds), extirpated fauna (e.g., crocodiles), and introduced vertebrates (e.g., zebu cattle). The disappearance of megafauna from the study sites at ~ 1000 years ago followed a relatively arid interval and closely coincides with increasingly frequent traces of human foraging, fire, and pastoralism. Our analyses fail to document drought-associated extirpation or multiple millennia of megafauna hunting and suggest that a late combination of hunting, forest clearance, and pastoralism drove extirpations.Results - Subfossils and chronology. - Charcoal. Discussion Method

Fish remains from the Formative Period (1000 BC-AD 400) of Lake Titicaca, Bolivia: Zooarchaeology and taphonomy

Abstract This paper presents a detailed zooarchaeological study of fish remains from the site of Kala Uyuni, Bolivia. The fish remains of 31 flotation samples from different archaeological contexts and dated to the Formative Period (1000 BC-AD 400) are described in terms of frequency, weight, taxa distribution, sizes, skeletal representations, and exposure to heat. The results confirm the importance of fish in the diet of the inhabitants of the site and provide insights about the particularities of their exploitation, consumption, and differential discard across the site throughout time. A strong decline in the procurement and consumption of fish is observed for the Late Formative which seems to be a consequence of both environmental and social processes. Published by Elsevier Ltd

Circulating sST2 and catestatin levels in patients with acute worsening of heart failure: a report from the CATSTAT‐HF study

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The Rise and Fall of Wiñaymarka: Rethinking Cultural and Environmental Interactions in the Southern Basin of Lake Titicaca

Investigations of how past human societies managed during times of major climate change can inform our understanding of potential human responses to ongoing environmental change. In this study, we evaluate the impact of environmental variation on human communities over the last four millennia in the southern Lake Titicaca basin of the Andes, known as Lake Wiñaymarka. Refined paleoenvironmental reconstructions from new diatom-based reconstructions of lake level together with archaeological evidence of animal and plant resource use from sites on the Taraco Peninsula, Bolivia, reveal frequent climate and lake-level changes within major cultural phases. We posit that climate fluctuations alone do not explain major past social and political transformations but instead that a highly dynamic environment contributed to the development of flexible and diverse subsistence practices by the communities in the Titicaca Basin

Taxonomic review of the genus Polylepis. Implications for ecological studies, conservation and restoration

Según los diversos tratamientos taxonómicos, el número de especies del género Polylepis oscila entre 33 y 28 especies. Sin embargo, hasta el momento no se pudieron delimitar claramente las especies de este género. Es difícil definir sus orígenes evolutivos y conocer los procesos de especiación. Esta complejidad obedecería a distintos procesos que actúan de forma independiente y sinérgica dependiendo del grupo de especies: diferenciación relativamente reciente, poliploidía, hibridación y el aparente rol del ser humano en su distribución. En este artículo realizamos una revisión de la situación taxonómica actual del género Polylepis. Proponemos 28 especies e incluimos 2 nuevas especies descriptas para Perú y una especie (P. tomentella) con tres subespecies. Además, discutimos los vacíos en el conocimiento y proponemos estrategias de investigación que permitan mejorar la delimitación de las especies. A fin de proveer una estructura taxonómica dentro de los estudios y para que los datos obtenidos constituyan un aporte a los procesos de conservación de estos bosques, taxónomos y conservacionistas debemos trabajar en conjunto para delimitar las unidades de conservación que eviten ambigüedades y para, de esta manera, definir estrategias claras.The number of species in the genus Polylepis has changed, according to the systematic treatments, from 33 to 28; however, until now there is not a clear species delimitation. It has been complicated to define evolutionary origins and understand speciation. This complexity may be the result of different processes acting independently or interacting: recent radiation, poliploidy, hibridization and the human intervention in its distribution, depending of the species group. In this article, we revised the taxonomic status of the genus Polylepis. Twenty-eight species are proposed, with the inclusion of two new species for Perú and one species (P. tomentella) with three subespecies. In addition, gaps of knowledge are analyzed and strategies of research are proposed to improve species delimitation. Incorporating a taxonomic structure could generate new insights to conservation, restoration and management projects; taxonomists and conservationist need to work together to define conservation units to avoid ambiguities and define new strategies