University of Caldas

International audience

Uranium-lead geochronology in detrital zircons and provenance analyses in eight boreholes and two surface stratigraphic sections in the northern Andes provide insight into the time of closure of the Central American Seaway. The timing of this closure has been correlated with Plio-Pleistocene global oceanographic, atmospheric, and biotic events. We found that a uniquely Panamanian Eocene detrital zircon fingerprint is pronounced in middle Miocene fluvial and shallow marine strata cropping out in the northern Andes but is absent in underlying lower Miocene and Oligocene strata. We contend that this fingerprint demonstrates a fluvial connection, and therefore the absence of an intervening seaway, between the Panama arc and South America in middle Miocene times; the Central American Seaway had vanished by that time.

Temperatures in tropical regions are estimated to have increased by 3° to 5°C, compared with Late Paleocene values, during the Paleocene-Eocene Thermal Maximum (PETM, 56.3 million years ago) event. We investigated the tropical forest response to this rapid warming by evaluating the palynological record of three stratigraphic sections in eastern Colombia and western Venezuela. We observed a rapid and distinct increase in plant diversity and origination rates, with a set of new taxa, mostly angiosperms, added to the existing stock of low-diversity Paleocene flora. There is no evidence for enhanced aridity in the northern Neotropics. The tropical rainforest was able to persist under elevated temperatures and high levels of atmospheric carbon dioxide, in contrast to speculations that tropical ecosystems were severely compromised by heat stress.

Ruminants are foregut fermenters that have the remarkable ability of converting plant polymers that are indigestible to humans into assimilable comestibles like meat and milk, which are cornerstones of human nutrition. Ruminants establish a symbiotic relationship with their microbiome, and the latter is the workhorse of carbohydrate fermentation. On the other hand, during carbohydrate fermentation, synthesis of propionate sequesters H, thus reducing its availability for the ultimate production of methane (CH4) by methanogenic archaea. Biochemically, methane is the simplest alkane and represents a downturn in energetic efficiency in ruminants; environmentally, it constitutes a potent greenhouse gas that negatively affects climate change. Prevotella is a very versatile microbe capable of processing a wide range of proteins and polysaccharides, and one of its fermentation products is propionate, a trait that appears conspicuous in P. ruminicola strain 23. Since propionate, but not acetate or butyrate, constitutes an H sink, propionate-producing microbes have the potential to reduce methane production. Accordingly, numerous studies suggest that members of the genus Prevotella have the ability to divert the hydrogen flow in glycolysis away from methanogenesis and in favor of propionic acid production. Intended for a broad audience in microbiology, our review summarizes the biochemistry of carbohydrate fermentation and subsequently discusses the evidence supporting the essential role of Prevotella in lignocellulose processing and its association with reduced methane emissions. We hope this article will serve as an introduction to novice Prevotella researchers and as an update to others more conversant with the topic.

OBJECTIVES: To assess the validity (convergent and construct) and reliability of the Short Physical Performance Battery (SPPB) among non-disabled adults between 65 to 74 years of age residing in the Andes Mountains of Colombia. METHODS: Design Validation study; PARTICIPANTS: 150 subjects aged 65 to 74 years recruited from elderly associations (day-centers) in Manizales, Colombia. MEASUREMENTS: The SPPB tests of balance, including time to walk 4 meters and time required to stand from a chair 5 times were administered to all participants. Reliability was analyzed with a 7-day interval between assessments and use of repeated ANOVA testing. Construct validity was assessed using factor analysis and by testing the relationship between SPPB and depressive symptoms, cognitive function, and self rated health (SRH), while the concurrent validity was measured through relationships with mobility limitations and disability in Activities of Daily Living (ADL). ANOVA tests were used to establish these associations. RESULTS: Test-retest reliability of the SPPB was high: 0.87 (CI95%: 0.77-0.96). A one factor solution was found with three SPPB tests. SPPB was related to self-rated health, limitations in walking and climbing steps and to indicators of disability, as well as to cognitive function and depression. There was a graded decrease in the mean SPPB score with increasing disability and poor health. CONCLUSION: The Spanish version of SPPB is reliable and valid to assess physical performance among older adults from our region. Future studies should establish their clinical applications and explore usage in population studies.

The number of Fungi is estimated at between 1.5 and 3 million. Lichenized species are thought to make up a comparatively small portion of this figure, with unrecognized species richness hidden among little-studied, tropical microlichens. Recent findings, however, suggest that some macrolichens contain a large number of unrecognized taxa, increasing known species richness by an order of magnitude or more. Here we report the existence of at least 126 species in what until recently was believed to be a single taxon: the basidiolichen fungus Dictyonema glabratum, also known as Cora pavonia. Notably, these species are not cryptic but morphologically distinct. A predictive model suggests an even larger number, with more than 400 species. These results call into question species concepts in presumably well-known macrolichens and demonstrate the need for accurately documenting such species richness, given the importance of these lichens in endangered ecosystems such as paramos and the alarming potential for species losses throughout the tropics.

A small Plinian eruption of the Nevado del Ruiz volcano in Colombia ejected 3.5 x 10(10) kilograms of mixed dacite and andesite tephra on 13 November 1985, with a maximum column height of 31 kilometers above sea level. Small pyroclastic flows and surges, generated during the initial stage of the eruption, caused surface melting of approximately 10% of the volcano's ice cap, leading to meltwater floods. The erosive floods incorporated soils and loose sediments from the volcano's flanks and developed into lahars, which claimed at least 25,000 lives.

Stage III non-small cell lung cancer (NSCLC) includes a highly heterogeneous group of patients with differences in the extent and localization of disease. Many aspects of stage III disease are controversial. The data supporting treatment approaches are often subject to a number of limitations, due to the heterogeneous patient populations involved in the trials. Furthermore, the definition of stage III disease has changed over time, and early studies were frequently inadequately powered to detect small differences in therapeutic outcome, were not randomized, or had a limited follow-up times. Major improvements in therapy, including the use of more active chemotherapy agents and refinements in radiation and surgical techniques, also limit the interpretation of earlier clinical trials. Lastly, improvements in pretreatment staging have led to reclassification of patients with relatively minimal metastatic disease as stage IV rather than stage III, leading to an apparent increase in the overall survival of both stage III and IV patients. Median overall stage III NSCLC survival ranges from 9 to 34 months. Higher survival rates are observed in younger Caucasian women with good performance status, adenocarcinoma, mutations, stage IIIA, and in patients with multidisciplinary-team-based diagnoses.

OBJECTIVES: To examine whether the association between emotional support and indicators of health and quality of life differs between Canadian and Latin American older adults. DESIGN: Cross-sectional analysis of the International Mobility in Aging Study (IMIAS). Social support from friends, family members, children and partner was measured with a previously validated social network and support scale (IMIAS-SNSS). Low social support was defined as ranking in the lowest site-specific quartile. Prevalence ratios (PR) of good health, depression and good quality of life were estimated with Poisson regression models, adjusting for age, gender, education, income and disability in activities of daily living. SETTING: Kingston and Saint-Hyacinthe in Canada, Manizales in Colombia and Natal in Brazil. PARTICIPANTS: 1600 community-dwelling adults aged 65-74 years, n=400 at each site. OUTCOME MEASURES: Likert scale question on self-rated health, Center for Epidemiological Studies Depression Scale and 10-point analogical quality-of-life (QoL) scale. RESULTS: Relationships between social support and study outcomes differed between Canadian and Latin American older adults. Among Canadians, those without a partner had a lower prevalence of good health (PR=0.90; 95% CI 0.82 to 0.98), and those with high support from friends had a higher prevalence of good health (PR=1.09; 95% CI 1.01 to 1.18). Among Latin Americans, depression was lower among those with high levels of support from family (PR=0.63; 95% CI 0.48 to 0.83), children (PR=0.60; 95% CI 0.45 to 0.80) and partner (PR=0.57; 95% CI 0.31 to 0.77); good QoL was associated with high levels of support from children (PR=1.54; 95% CI 1.20 to 1.99) and partner (PR=1.31; 95% CI 1.03 to 1.67). CONCLUSIONS: Among older adults, different sources of support were relevant to health across societies. Support from friends and having a partner were related to good health in Canada, whereas in Latin America, support from family, children and partner were associated with less depression and better QoL.

INTRODUCTION: Acromegaly is a rare, insidious disease resulting from the overproduction of growth hormone (GH) and insulin-like growth factor 1 (IGF-1), and is associated with a range of comorbidities. The extent of associated complications and mortality risk is related to length of exposure to the excess GH and IGF-1, thus early diagnosis and treatment is imperative. Unfortunately, acromegaly is often diagnosed late, when patients already have a wide range of comorbidities. The presence of comorbid conditions contributes significantly to patient morbidity/mortality and impaired quality of life. METHODS: We conducted a retrospective literature review for information relating to the diagnosis of acromegaly, and its associated comorbidities using PubMed. The main aim of this review is to highlight the issues of comorbidities in acromegaly, and to reinforce the importance of early diagnosis and treatment. FINDINGS AND CONCLUSIONS: Successful management of acromegaly goes beyond treating the disease itself, since many patients are diagnosed late in disease evolution, they present with a range of comorbid conditions, such as cardiovascular disease, diabetes, hypertension, and sleep apnea. It is important that patients are screened carefully at diagnosis (and thereafter), for common associated complications, and that biochemical control does not become the only treatment goal. Mortality and morbidities in acromegaly can be reduced successfully if patients are treated using a multimodal approach with comprehensive comorbidity management.

Staphylococcus aureus is recognized worldwide as one of the major agents of dairy cow intra-mammary infections. This microorganism can express a wide spectrum of pathogenic factors used to attach, colonize, invade and infect the host. The present study evaluated 120 isolates from eight different countries that were genotyped by RS-PCR and investigated for 26 different virulence factors to increase the knowledge on the circulating genetic lineages among the cow population with mastitis. New genotypes were observed for South African strains while for all the other countries new variants of existing genotypes were detected. For each country, a specific genotypic pattern was found. Among the virulence factors, fmtB, cna, clfA and leucocidins genes were the most frequent. The sea and sei genes were present in seven out of eight countries; seh showed high frequency in South American countries (Brazil, Colombia, Argentina), while sel was harboured especially in one Mediterranean country (Tunisia). The etb, seb and see genes were not detected in any of the isolates, while only two isolates were MRSA (Germany and Italy) confirming the low diffusion of methicillin resistance microorganism among bovine mastitis isolates. This work demonstrated the wide variety of S. aureus genotypes found in dairy cattle worldwide. This condition suggests that considering the region of interest might help to formulate strategies for reducing the infection spreading.

O conteúdo de compostos fenólicos, incluindo resveratrol, antocianinas e outros flavonóides, e a capacidade antioxidante de cinco cultivares de uvas produzidas em Minas Gerais foram determinados. O conteúdo de fenólicos totais, determinado através do método de Folin-Ciocalteau variou significativamente, entre 65 ± 1 e 390 ± 30 mg equivalentes de ácido gálico.100 g -1 de amostra base úmida (b.u.). O conteúdo de antocianinas totais quantificado por CLAE variou entre 6,7 ± 0,2 e 154 ± 4 mg equivalentes de cianidina.100 g -1 (b.u.). Outros flavonóides encontrados foram catequina, epicatequina, quercetina, caempferol além dos ácidos hidroxicinâmicos. O resveratrol foi encontrado em três cultivares, variando entre 0,022 ± 0,001 e 0,60 ± 0,03 mg.100 g -1 (b.u.). A capacidade antioxidante foi analisada usando o método de seqüestro de radicais livres do DPPH (2,2-difenil-1-picrilhidrazila), que variou entre 2,7 ± 0,1 e 19 ± 2 µmoles equivalentes de Trolox.g -1 de amostra (b.u.), mostrando boa correlação com o conteúdo de fenólicos totais. As uvas tintas de coloração mais escura apresentaram maior conteúdo de antocianinas, e conseqüentemente maior teor de fenólicos totais e capacidade antioxidante.

Transposable elements (TEs) are genomic units able to move within the genome of virtually all organisms. Due to their natural repetitive numbers and their high structural diversity, the identification and classification of TEs remain a challenge in sequenced genomes. Although TEs were initially regarded as "junk DNA", it has been demonstrated that they play key roles in chromosome structures, gene expression, and regulation, as well as adaptation and evolution. A highly reliable annotation of these elements is, therefore, crucial to better understand genome functions and their evolution. To date, much bioinformatics software has been developed to address TE detection and classification processes, but many problematic aspects remain, such as the reliability, precision, and speed of the analyses. Machine learning and deep learning are algorithms that can make automatic predictions and decisions in a wide variety of scientific applications. They have been tested in bioinformatics and, more specifically for TEs, classification with encouraging results. In this review, we will discuss important aspects of TEs, such as their structure, importance in the evolution and architecture of the host, and their current classifications and nomenclatures. We will also address current methods and their limitations in identifying and classifying TEs.

Advances in Deep Learning (DL) have provided alternative approaches to various complex problems, including the domain of spatial image steganalysis using Convolutional Neural Networks (CNN). Several CNN architectures have been developed in recent years, which have improved the detection accuracy of steganographic images. This work presents a novel CNN architecture which involves a preprocessing stage using filter banks to enhance steganographic noise, a feature extraction stage using depthwise and separable convolutional layers, and skip connections. Performance was evaluated using the BOSSbase 1.01 and BOWS 2 datasets with different experimental setups, including adaptive steganographic algorithms, namely WOW, S-UNIWARD, MiPOD, HILL and HUGO. Our results outperformed works published in the last few years in every experimental setting. This work improves classification accuracies on all algorithms and bits per pixel (bpp), reaching 80.3% on WOW with 0.2 bpp and 89.8% on WOW with 0.4 bpp, 73.6% and 87.1% on S-UNIWARD (0.2 and 0.4 bpp respectively), 68.3% and 81.4% on MiPOD (0.2 and 0.4 bpp), 68.5% and 81.9% on HILL (0.2 and 0.4 bpp), 74.6% and 84.5% on HUGO (0.2 and 0.4 bpp), using BOSSbase 1.01 test data.

BACKGROUND: This study aimed to estimate the prevalence and associated factors related to frailty, by Fried criteria, in the elderly population in a rural area in the Andes Mountains, and to analyze the relationship of these with comorbidity and disability. METHODS: A cross-sectional study was undertaken involving 1878 participants 60 years of age and older. The frailty syndrome was diagnosed based on the Fried criteria (weakness, low speed, low physical activity, exhaustion, and weight loss). Variables were grouped as theoretical domains and, along with other potential confounders, were placed into five categories: (a) demographic and socioeconomic status, (b) health status, (c) self-reported functional status, (d) physical performance-based measures, and (e) psychosocial factors. Chi-square, ANOVA, and multinomial logistic regression analyses were used to test the prognostic value of frailty for the outcomes of interest. RESULTS: The prevalence of frailty was 12.2%. Factors associated with frailty were age, gender, health status variables that included self-perceived health and number of chronic conditions, functional covariate variables that included disability in activities in daily living (ADL), disabilities in instrumental ADL, chair stand time, and psychosocial variables that included depressive symptoms and cognitive impairment. Higher comorbidity and disability was found in frail elderly people. Only a subset of frail elderly people (10%) reported no disease or disability. CONCLUSIONS: A relevant number of elderly persons living in rural areas in the Andes Mountains are frail. The prevalence of frailty is similar to that reported in other populations in the Latin American region. Our results support the use of modified Cardiovascular Health Study criteria to measure frailty in communities other than urban settings. Frailty in this study was strongly associated with comorbidities, and frailty and comorbidity predicted disability.

BACKGROUND: falls and fall-related injuries are common in older adults, have negative effects both on quality of life and functional independence and are associated with increased morbidity, mortality and health care costs. Current clinical approaches and advice from falls guidelines vary substantially between countries and settings, warranting a standardised approach. At the first World Congress on Falls and Postural Instability in Kuala Lumpur, Malaysia, in December 2019, a worldwide task force of experts in falls in older adults, committed to achieving a global consensus on updating clinical practice guidelines for falls prevention and management by incorporating current and emerging evidence in falls research. Moreover, the importance of taking a person-centred approach and including perspectives from patients, caregivers and other stakeholders was recognised as important components of this endeavour. Finally, the need to specifically include recent developments in e-health was acknowledged, as well as the importance of addressing differences between settings and including developing countries. METHODS: a steering committee was assembled and 10 working Groups were created to provide preliminary evidence-based recommendations. A cross-cutting theme on patient's perspective was also created. In addition, a worldwide multidisciplinary group of experts and stakeholders, to review the proposed recommendations and to participate in a Delphi process to achieve consensus for the final recommendations, was brought together. CONCLUSION: in this New Horizons article, the global challenges in falls prevention are depicted, the goals of the worldwide task force are summarised and the conceptual framework for development of a global falls prevention and management guideline is presented.

Cancer classification is a topic of major interest in medicine since it allows accurate and efficient diagnosis and facilitates a successful outcome in medical treatments. Previous studies have classified human tumors using a large-scale RNA profiling and supervised Machine Learning (ML) algorithms to construct a molecular-based classification of carcinoma cells from breast, bladder, adenocarcinoma, colorectal, gastro esophagus, kidney, liver, lung, ovarian, pancreas, and prostate tumors. These datasets are collectively known as the 11_tumor database, although this database has been used in several works in the ML field, no comparative studies of different algorithms can be found in the literature. On the other hand, advances in both hardware and software technologies have fostered considerable improvements in the precision of solutions that use ML, such as Deep Learning (DL). In this study, we compare the most widely used algorithms in classical ML and DL to classify the tumors described in the 11_tumor database. We obtained tumor identification accuracies between 90.6% (Logistic Regression) and 94.43% (Convolutional Neural Networks) using k -fold cross-validation. Also, we show how a tuning process may or may not significantly improve algorithms’ accuracies. Our results demonstrate an efficient and accurate classification method based on gene expression (microarray data) and ML/DL algorithms, which facilitates tumor type prediction in a multi-cancer-type scenario.

Abstract A geological transect across the suture separating northwestern South America from the Panama Arc helps document the provenance and thermal history of both crustal domains and the suture zone. During middle Miocene, strata were being accumulated over the suture zone between the Panama Arc and the continental margin. Integrated provenance analyses of those middle Miocene strata show the presence of mixed sources that includes material derived from the two major crustal domains: the old northwestern South American orogens and the younger Panama Arc. Coeval moderately rapid exhumation of Upper Cretaceous to Paleogene sediments forming the reference continental margin is suggested from our inverse thermal modeling. Strata within the suture zone are intruded by ~12 Ma magmatic arc‐related plutons, marking the transition from a collisional orogen to a subduction‐related one. Renewed late Miocene to Pliocene acceleration of the exhumation rates is the consequence of a second tectonic pulse, which is likely to be triggered by the onset of a flat‐slab subduction of the Nazca plate underneath the northernmost Andes of Colombia, suggesting that late Miocene to Pliocene orogeny in the Northern Andes is controlled by at least two different tectonic mechanisms.

Changes in global and regional precipitation regimes are among the most pervasive components of climate change. Intensification of rainfall cycles, ranging from frequent downpours to severe droughts, could cause widespread, but largely unknown, alterations to trophic structure and ecosystem function. We conducted multi-site coordinated experiments to show how variation in the quantity and evenness of rainfall modulates trophic structure in 210 natural freshwater microcosms (tank bromeliads) across Central and South America (18°N to 29°S). The biomass of smaller organisms (detritivores) was higher under more stable hydrological conditions. Conversely, the biomass of predators was highest when rainfall was uneven, resulting in top-heavy biomass pyramids. These results illustrate how extremes of precipitation, resulting in localized droughts or flooding, can erode the base of freshwater food webs, with negative implications for the stability of trophic dynamics.

Ruminants contribute to the emissions of greenhouse gases, in particular methane, due to the microbial anaerobic fermentation of feed in the rumen. The rumen simulation technique was used to investigate the effects of the addition of different supplemental plant oils to a high concentrate diet on ruminal fermentation and microbial community composition. The control (CTR) diet was a high-concentrate total mixed ration with no supplemental oil. The other experimental diets were supplemented with olive (OLV), sunflower (SFL) or linseed (LNS) oils at 6%. Rumen digesta was used to inoculate the fermenters, and four fermentation units were used per treatment. Fermentation end-products, extent of feed degradation and composition of the microbial community (qPCR) in digesta were determined. Compared with the CTR diet, the addition of plant oils had no significant (P > 0.05) effect on ruminal pH, substrate degradation, total volatile fatty acids or microbial protein synthesis. Gas production from the fermentation of starch or cellulose were decreased by oil supplementation. Methane production was reduced by 21-28% (P < 0.001), propionate production was increased (P < 0.01), and butyrate and ammonia outputs and the acetate to propionate ratio were decreased (P < 0.001) with oil-supplemented diets. Addition of 6% OLV and LNS reduced (P < 0.05) copy numbers of total bacteria relative to the control. In conclusion, the supplementation of ruminant diets with plant oils, in particular from sunflower or linseed, causes some favorable effects on the fermentation processes. The addition of vegetable oils to ruminant mixed rations will reduce methane production increasing the formation of propionic acid without affecting the digestion of feed in the rumen. Adding vegetable fats to ruminant diets seems to be a suitable approach to decrease methane emissions, a relevant cleaner effect that may contribute to alleviate the environmental impact of ruminant production.