1,787 research outputs found
Combining Heuristics in Assembly Sequence Planning
Assembly Sequence Planning is tackled by modelling and solving a
planning problem that considers the execution of the plan in a system with multiple
assembly machines. The objective of the plan is the minimization of the total
assembly time (makespan). To meet this objective, the model takes into account the
durations and resources for the assembly tasks, the change of configuration in the
machines, and the transportation of intermediate subassemblies between different
workstations. In order to solve the problem, different heuristics has been defined
from two relaxed model of it, one considering only the precedence constraints among
tasks, and the other one considering only the use of shared resources. From these
basic heuristics, other ones have been defined, combining both types of information
from the problem, so that the refinement produces substantial improvements over the
initial heuristics.Ministerio de Ciencia y TecnologíaDPI2003-07146-C02-0
Usos tradicionales de la vid silvestre euroasiática en la Península Ibérica
The Iberian Peninsula constitutes the Western limit of the dioecious Eurasian wild grapevine (Vitis vinifera L. subsp. sylvestris). At present, it is a threatened plant, due to human impacts. This liana has had different uses in this territory from the Paleolithic until the end of the last century, including several medicinal applications, inherited from the classical Greek culture. In order to retrieve the available written information, we carried out an exhaustive bibliographic search of the pharmacopoeia linked to this Vitaceae, from the 16th century to the present day. Current references on chemical composition of different parts of grapevine and their medicinal uses were also covered. In parallel, we conducted research in several archives and made inquiries to historians, anthropologists, and sanitary personnel. We also interviewed elderly people from rural areas of Spain and Portugal where some relic populations of wild grapevine are still conserved. Among the written and oral medicinal uses compiled, the main ones are: the use of the grapevine bleeding water to alleviate eczema and skin eruptions and to combat conjunctivitis and keratitis; the use of must from unripe berries (agua de agraz in Spanish) as liver tonic and to treat digestive diseases; the leaves were used to reduce edema, as antihemorrhoidal, and for menopausal disorders; and finally, the vinegar was used to clean and disinfect wounds both on humans and animals. This paper highlights the tremendous erosion of the traditional knowledge about this relevant plant genetic resource.La Península Ibérica constituye el límite occidental de la euroasiática y dioica vid silvestre (Vitis vinifera L. subsp. sylvestris). Actualmente la vid silvestre se encuentra amenazada debido al impacto humano. Esta liana tuvo diferentes usos en la península desde el Paleolítico hasta finales del siglo pasado. Entre ellos, como herencia de la cultura griega clásica, aparecen diferentes usos médicos. Para recuperar la información escrita existente, hemos llevado a cabo una búsqueda bibliográfica exhaustiva sobre la farmacopea vinculada a esta Vitaceae, desde el siglo XVI hasta el presente. Incluimos también referencias sobre la composición química de diferentes partes de la vid y sus usos medicinales. Paralelamente, hemos investigado en los archivos de diferentes localidades y realizado consultas a historiadores, antropólogos y personal sanitario. Asimismo, hemos realizado entrevistas a ancianos de diferentes regiones de España y Portugal donde todavía se conservan algunas poblaciones relictas de vid silvestre. Entre la información escrita y oral de los usos medicinales recopilados, mencionaremos el uso del “agua de lloro” de la vid para aliviar eczemas y erupciones cutáneas; para combatir la conjuntivitis y la queratitis; el mosto o “agua de agraz”, como tónico para el hígado y para tratar afecciones digestivas; las hojas para reducir el edema, como antihemorroidales y para trastornos de la menopausia; y por último, el vinagre para limpiar y desinfectar heridas de personas y animales. Este trabajo destaca la tremenda erosión del conocimiento tradicional sobre este recurso fitogenético tan relevante
Risk factors and prevalence of osteoporosis in premenopausal women from poor economic backgrounds in Colombia
INTRODUCTION: The prevalence of osteoporosis in premenopausal women along with associated risk factors has not been well elucidated. Recent studies have shown that poverty is a risk factor for osteoporosis. OBJECTIVE: To determine the prevalence of osteoporosis and its risk factors in a group of premenopausal women of poor economic background in Colombia. MATERIALS AND METHODS: The study comprised 1483 women between 35 and 53 years of age with at least one risk factor for osteoporosis. Demographic characteristics, reproductive factors, comorbidities, and risk factors for osteoporosis were evaluated. Lumbar vertebrae (L2–L4) and the femur neck were assessed using dual-energy X-ray absorptiometry. RESULTS: Of the 1483 patients, 1443 (97.3%) had at least one risk factor for osteoporosis and 40 (2.7%) had no risk factors. Patients with one risk factor were referred to have a dual-energy X-ray absorptiometry scan, which 795 women completed. Osteopenia was found in 30.5% and osteoporosis in 4.8% of these women. The majority of these women were homemakers, and 18.5% of the patients with osteoporosis were also illiterate (P < 0.001). The risk factors identified in this population were: hypothyroidism (odds ratio [OR] = 5.19, 95% confience interval [CI]:1.6–16), age over 45 years old (OR = 1.13, 95% CI: 1.0–1.2), a history of malnutrition or low birth weight (OR = 2.35, 95% CI: 1.0–5.2), or early-onset menopause (OR = 3.4, 95% CI: 1.6–7.2). CONCLUSION: Premenopausal Colombian women from impoverished areas showed increased rates of osteopenia and osteoporosis compared with the data described in the current literature. Hypothyroidism was an outstanding risk factor in Colombian premenopausal women with osteoporosis. This shows the influence of poverty and other risk factors on the onset of osteoporosis in women aged 35–53 years
Delivering beneficial microorganisms for corals: rotifers as carriers of probiotic bacteria
The use of Beneficial Microorganisms for Corals (BMCs) to increase the resistance of corals to environmental stress has proven to be effective in laboratory trials. Because direct inoculation of BMCs in larger tanks or in the field can be challenging, a delivery mechanism is needed for efficient transmission of the BMC consortium. Packaged delivery mechanisms have been successfully used to transmit probiotics to other organisms, including humans, lobsters, and fish. Here, we tested a method for utilizing rotifers of the species Brachionus plicatilis for delivery of BMCs to corals of the species Pocillopora damicornis. Epifluorescence microscopy combined with a live/dead cell staining assay was used to evaluate the viability of the BMCs and monitor their in vivo uptake by the rotifers. The rotifers efficiently ingested BMCs, which accumulated in the digestive system and on the body surface after 10 min of interaction. Scanning electron microscopy confirmed the adherence of BMCs to the rotifer surfaces. BMC-enriched rotifers were actively ingested by P. damicornis corals, indicating that this is a promising technique for administering coral probiotics in situ. Studies to track the delivery of probiotics through carriers such as B. plicatilis, and the provision or establishment of beneficial traits in corals are the next proof-of-concept research priorities
Identical repeated backbone of the human genome
<p>Abstract</p> <p>Background</p> <p>Identical sequences with a minimal length of about 300 base pairs (bp) have been involved in the generation of various meiotic/mitotic genomic rearrangements through non-allelic homologous recombination (NAHR) events. Genomic disorders and structural variation, together with gene remodelling processes have been associated with many of these rearrangements. Based on these observations, we identified and integrated all the 100% identical repeats of at least 300 bp in the NCBI version 36.2 human genome reference assembly into non-overlapping regions, thus defining the Identical Repeated Backbone (IRB) of the reference human genome.</p> <p>Results</p> <p>The IRB sequences are distributed all over the genome in 66,600 regions, which correspond to ~2% of the total NCBI human genome reference assembly. Important structural and functional elements such as common repeats, segmental duplications, and genes are contained in the IRB. About 80% of the IRB bp overlap with known copy-number variants (CNVs). By analyzing the genes embedded in the IRB, we were able to detect some identical genes not previously included in the Ensembl release 50 annotation of human genes. In addition, we found evidence of IRB gene copy-number polymorphisms in raw sequence reads of two diploid sequenced genomes.</p> <p>Conclusions</p> <p>In general, the IRB offers new insight into the complex organization of the identical repeated sequences of the human genome. It provides an accurate map of potential NAHR sites which could be used in targeting the study of novel CNVs, predicting DNA copy-number variation in newly sequenced genomes, and improve genome annotation.</p
Effect of β-Blocker Withdrawal on Functional Capacity in Heart Failure and Preserved Ejection Fraction
BACKGROUND Chronotropic incompetence has shown to be associated with a decrease in exercise capacity in heart
failure with preserved ejection fraction (HFpEF), yet b-blockers are commonly used in HFpEF despite the lack of robust
evidence.
OBJECTIVES This study aimed to evaluate the effect of b-blocker withdrawal on peak oxygen consumption (peak VO2)
in patients with HFpEF and chronotropic incompetence.
METHODS This is a multicenter, randomized, investigator-blinded, crossover clinical trial consisting of 2 treatment
periods of 2 weeks separated by a washout period of 2 weeks. Patients with stable HFpEF, New York Heart Association
functional classes II and III, previous treatment with b-blockers, and chronotropic incompetence were first randomized to
withdrawing from (arm A: n ¼ 26) versus continuing (arm B: n ¼ 26) b-blocker treatment and were then crossed over to
receive the opposite intervention. Changes in peak VO2 and percentage of predicted peak VO2 (peak VO2%) measured at
the end of the trial were the primary outcome measures. To account for the paired-data nature of this crossover trial,
linear mixed regression analysis was used.
RESULTS The mean age was 72.6 13.1 years, and most of the patients were women (59.6%) in New York Heart
Association functional class II (66.7%). The mean peakVO2 and peak VO2% were 12.4 2.9 mL/kg/min, and 72.4 17.8%,
respectively. No significant baseline differences were found across treatment arms. Peak VO2 and peak VO2% increased
significantly after b-blocker withdrawal (14.3 vs 12.2 mL/kg/min [D þ2.1 mL/kg/min]; P < 0.001 and 81.1 vs 69.4%
[D þ11.7%]; P < 0.001, respectively).
CONCLUSIONS b-blocker withdrawal improved maximal functional capacity in patients with HFpEF and chronotropic
incompetence. b-blocker use in HFpEF deserves profound re-evaluation. (b-blockers Withdrawal in Patients With HFpEF
and Chronotropic Incompetence: Effect on Functional Capacity [PRESERVE-HR]; NCT03871803; 2017-005077-39)
(J Am Coll Cardiol 2021;78:2042–2056) © 2021 The Authors. Published by Elsevier on behalf of the American College of
Cardiology Foundation
Miopatía por cuerpos de inclusión. Caso clínico y revisión de la literatura
La miositis por cuerpos de inclusión (MCI) es una patología poco común que se presenta en individuos mayores de 50 años y con mayor frecuencia en hombres; sin embargo, los síntomas pueden empezar 20 años antes de su diagnóstico. Hasta un 30% de los casos de miopatías inflamatorias pueden ser de MCI y su prevalencia varía en los diferentes países y grupos étnicos. Clínicamente se manifiesta como debilidad lentamente progresiva proximal y distal. En este artículo se presenta un caso de una paciente de 78 años con antecedentes previos de diabetes mellitus tipo 2, hipertensión arterial, e hipotiroidismo, con cuadro de 18 meses de evolución consistente en debilidad de miembros inferiores, incapacidad para subir y bajar escaleras, limitación en la marcha, acompañado de disestesias. Se realizó la medición de la creatin quinasa (CK) y su valor inicial fue 7820, la electromiografía y neuroconducciones mostraron polineuropatia axonal motora en las cuatro extremidades y miopatía inflamatoria. Se trató con glucorticoides a dosis de 1 mg/kg y después de seis meses de tratamiento no se observó mejoría. Se decide tomar biopsia muscular que mostró miopatía por cuerpos de inclusión, lo que explicó la falla terapéutica inicial. Este caso es interesante desde el punto de vista clínico, ya que no es frecuente la elevación de la CK en los niveles que presentó la paciente y por las múltiples comorbilidades asociadas
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Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates
Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis).
Time period: Tree-inventory plots established between 1934 and 2019.
Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm.
Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield.
Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes.
Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests.
Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types
Geography and ecology shape the phylogenetic composition of Amazonian tree communities
AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions
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