121 research outputs found
Acumulaciones de hierro en agroecosistemas bananeros (Milagro, Ecuador): Una revisión bibliográfica de algunos factores que intervienen en la salud y nutrición del cultivo
This literature review describes from the agronomic point of view, the problems associated with Fe accumulation in banana agroecosystems. The objective of this research was to analyze the factors involved in the accumulation of large amounts of Fe in banana plantations, through the analysis of literature published on this subject in different databases, and the information was compared with foliar and soil analysis of a banana plantation located around Milagro, Ecuador. Results show several factors influencing the accumulation of Fe, which can be transported to the foliage, for which the type of soil is a determining factor together with the cultural practices that preserve the soil microbiome, being the drivers of siderophore metabolites that retain or metabolize heavy metals such as Fe. The results of foliar and soil analysis show nutritional imbalances caused by anthropogenic factors and a high bioaccumulation of Fe in the banana crop in the studied area. In conclusion, we can presently understand better the role of Fe in the banana plantation; however, more research on this element related to anthropogenic pressure and the type of plantation soil needs to be developed. In addition, it is important to explore the biotechnological opportunities that can be offered by siderophore microorganisms present in banana agroecosystems.La presente revisión bibliográfica describe desde el punto de vista agronómico las problemáticas asociadas a la acumulación de hierro (Fe) en agroecosistemas bananeros. El objetivo de esta investigación fue analizar los factores que intervienen en la acumulación de grandes cantidades de Fe en plantaciones bananeras, a través de análisis de literatura publicados sobre este tema en distintas bases de datos, la información fue comparada con análisis foliares y suelos de una plantación bananera ubicada en la zona de Milagro, Ecuador. Los resultados muestran diversos factores que influyen en la acumulación de Fe y que el mismo puede ser transportado al follaje, para lo que el tipo de suelo es un factor determinante junto a las labores culturales que preservan el microbioma del suelo, siendo los impulsores de metabolitos sideróforos que retienen o metabolizan los metales pesados como el Fe. Los resultados de análisis foliares y de suelos muestran desequilibrios nutricionales ocasionados por factores antropogénicos y una alta bioacumulación de Fe en el cultivo de banano de la zona estudiada. En conclusión, al momento podemos comprender mejor el papel que desempeña el Fe en la plantación bananera; no obstante, se tienen que desarrollar más investigaciones de este elemento relacionado a la presión antropogénica y el tipo de suelo de la plantación. Además, es importante explorar las oportunidades biotecnológicas que pueden ofrecer los microorganismos sideróforos presentes en los agroecosistemas bananeros
Preliminary study of arbuscular mycorrhizae present in Phytelephas aequatorialis located in three coastal agroecosystems
The tagua, Phytelephas aequatorialis Spruce (Arecaceae) is a palm characterized by being dioecious and grows wild. In tropical regions such as Ecuador, its population has declined due to agricultural expansion and slow regeneration. At present, the flora surrounding it and the rhizosphere that could be associated with its adaptation to different ecological niches in the Ecuadorian coast are unknown. To evaluate the presence of arbuscular mycorrhizal fungi (AMF) associated with tagua, in three agrosystems of the Ecuadorian coast. The research was carried out in three agroecosystems where P. aequatorialis grows without being the dominant plant. Samples were obtained around the tagua plant, first the floristic composition was determined by taking photos and identifying the plant species in the site within a 2 m radius. Then soil and root samples collected during the months of November 2018 to February 2019 were taken in rural localities of Milagro, Guayaquil and Jipijapa canton. Spore abundance was higher in the Guayaquil agroecosystem with 550 spores per 100 g of soil, followed by the Milagro agroecosystem with 221 spores per 100 g of soil. The Milagro agroecosystem reached 63 % in the percentage of mycorrhizal colonization compared to Guayaquil and Jipijapa, which obtained 51 and 48 % respectively. The results show the presence of arbuscular mycorrhizae with different intensity in the three agroecosystems of P. aequatorialis studied, however, the floristic composition and environmental conditions may influence the development of mycorrhizal colonization.La tagua, Phytelephas aequatorialis Spruce (Arecaceae) es una palma caracterizada por ser dioica y crece en la región tropical de Ecuador, donde su población ha disminuido debido a la expansión agrícola y a su lenta regeneración. En la actualidad, se desconoce la flora circundante a ella y la rizósfera que podría estar asociada con su adaptación a diferentes nichos ecológicos. Evaluar la presencia de micorrizas arbusculares asociados a tagua, en tres agroecosistemas de P. aequatorialis en el litoral ecuatoriano. Las muestras de suelo y raíces fueron recolectadas alrededor de la planta de tagua en agroecosistemas mixtos en las localidades rurales del cantón Milagro, Guayaquil y Jipijapa, además se determinó la composición florística mediante la toma de fotos e identificación en el sitio de las especies vegetales en un radio de 2 m. La abundancia de esporas fue mayor en el agroecosistema Guayaquil con 550 esporas por cada 100 g de suelo, seguido por el agroecosistema Milagro con 221 esporas por cada 100 g de suelo. El agroecosistema Milagro alcanzó 63 % en el porcentaje de colonización micorrízica en comparación a Guayaquil y Jipijapa, quienes obtuvieron 51 y 48 % respectivamente. Los resultados muestran la presencia de micorrizas arbusculares con distinta intensidad en los tres agroecosistemas de P. aequatorialis estudiados, sin embargo, la composición florística y las condiciones ambientales pueden tener influencia en el desarrollo de la colonización micorrízica
Challenges to managing ecosystems sustainably for poverty alleviation: securing well-being in the Andes/Amazon: final report
Artritis reactiva por vacuna contra covid-19: revisión de caso
This research work entitled Reactive arthritis due to covid-19 vaccine: case review, reviews the case of a 13-year-old adolescent with no relevant pathological history who presents discomfort and inflammation in the left coxofemoral joint, ankle, dry eyes and dysuria of 4 weeks of evolution without response to ibuprofen. She has received the full dose of vaccination against COVID-19. Final diagnosis: Reiter's syndrome secondary to the application of the SARS-CoV-2 vaccine. The document is composed of an introduction, presentation of the case, review of the topic, discussion, conclusions and recommendations.El presente trabajo de investigación titulado Artritis reactiva por vacuna contra covid-19: revisión de caso, realiza una revisión del caso de un adolescente de 13 años sin antecedentes patológicos relevantes que presenta molestias e inflamación en la articulación coxofemoral izquierda, tobillo, resequedad ocular y disuria de 4 semanas de evolución sin respuesta al ibuprofeno. Ha recibido la dosis completa de vacunación contra el COVID-19. Diagnóstico final: Síndrome de Reiter secundario a aplicación de vacuna contra SARS-CoV-2. El documento está compuesto de introducción, presentación del caso, revisión del tema, discusión, conclusiones y recomendaciones
Current anti-doping policy: a critical appraisal
BACKGROUND: Current anti-doping in competitive sports is advocated for reasons of fair-play and concern for the athlete's health. With the inception of the World Anti Doping Agency (WADA), anti-doping effort has been considerably intensified. Resources invested in anti-doping are rising steeply and increasingly involve public funding. Most of the effort concerns elite athletes with much less impact on amateur sports and the general public. DISCUSSION: We review this recent development of increasingly severe anti-doping control measures and find them based on questionable ethical grounds. The ethical foundation of the war on doping consists of largely unsubstantiated assumptions about fairness in sports and the concept of a "level playing field". Moreover, it relies on dubious claims about the protection of an athlete's health and the value of the essentialist view that sports achievements reflect natural capacities. In addition, costly antidoping efforts in elite competitive sports concern only a small fraction of the population. From a public health perspective this is problematic since the high prevalence of uncontrolled, medically unsupervised doping practiced in amateur sports and doping-like behaviour in the general population (substance use for performance enhancement outside sport) exposes greater numbers of people to potential harm. In addition, anti-doping has pushed doping and doping-like behaviour underground, thus fostering dangerous practices such as sharing needles for injection. Finally, we argue that the involvement of the medical profession in doping and anti-doping challenges the principles of non-maleficience and of privacy protection. As such, current anti-doping measures potentially introduce problems of greater impact than are solved, and place physicians working with athletes or in anti-doping settings in an ethically difficult position. In response, we argue on behalf of enhancement practices in sports within a framework of medical supervision. SUMMARY: Current anti-doping strategy is aimed at eradication of doping in elite sports by means of all-out repression, buttressed by a war-like ideology similar to the public discourse sustaining international efforts against illicit drugs. Rather than striving for eradication of doping in sports, which appears to be an unattainable goal, a more pragmatic approach aimed at controlled use and harm reduction may be a viable alternative to cope with doping and doping-like behaviour
An Analysis of the Systemic Risks Posed by Fannie Mae and Freddie Mac and an Evaluation of the Policy Options for Reducing those Risks
CfA3: 185 Type Ia Supernova Light Curves from the CfA
We present multi-band photometry of 185 type-Ia supernovae (SN Ia), with over
11500 observations. These were acquired between 2001 and 2008 at the F. L.
Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics (CfA).
This sample contains the largest number of homogeneously-observed and reduced
nearby SN Ia (z < 0.08) published to date. It more than doubles the nearby
sample, bringing SN Ia cosmology to the point where systematic uncertainties
dominate. Our natural system photometry has a precision of 0.02 mag or better
in BVRIr'i' and roughly 0.04 mag in U for points brighter than 17.5 mag. We
also estimate a systematic uncertainty of 0.03 mag in our SN Ia standard system
BVRIr'i' photometry and 0.07 mag for U. Comparisons of our standard system
photometry with published SN Ia light curves and comparison stars, where
available for the same SN, reveal agreement at the level of a few hundredths
mag in most cases. We find that 1991bg-like SN Ia are sufficiently distinct
from other SN Ia in their color and light-curve-shape/luminosity relation that
they should be treated separately in light-curve/distance fitter training
samples. The CfA3 sample will contribute to the development of better
light-curve/distance fitters, particularly in the few dozen cases where
near-infrared photometry has been obtained and, together, can help disentangle
host-galaxy reddening from intrinsic supernova color, reducing the systematic
uncertainty in SN Ia distances due to dust.Comment: Accepted to the Astrophysical Journal. Minor changes from last
version. Light curves, comparison star photometry, and passband tables are
available at http://www.cfa.harvard.edu/supernova/CfA3
Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector
A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Genetic mechanisms of critical illness in COVID-19.
Host-mediated lung inflammation is present1, and drives mortality2, in the critical illness caused by coronavirus disease 2019 (COVID-19). Host genetic variants associated with critical illness may identify mechanistic targets for therapeutic development3. Here we report the results of the GenOMICC (Genetics Of Mortality In Critical Care) genome-wide association study in 2,244 critically ill patients with COVID-19 from 208 UK intensive care units. We have identified and replicated the following new genome-wide significant associations: on chromosome 12q24.13 (rs10735079, P = 1.65 × 10-8) in a gene cluster that encodes antiviral restriction enzyme activators (OAS1, OAS2 and OAS3); on chromosome 19p13.2 (rs74956615, P = 2.3 × 10-8) near the gene that encodes tyrosine kinase 2 (TYK2); on chromosome 19p13.3 (rs2109069, P = 3.98 × 10-12) within the gene that encodes dipeptidyl peptidase 9 (DPP9); and on chromosome 21q22.1 (rs2236757, P = 4.99 × 10-8) in the interferon receptor gene IFNAR2. We identified potential targets for repurposing of licensed medications: using Mendelian randomization, we found evidence that low expression of IFNAR2, or high expression of TYK2, are associated with life-threatening disease; and transcriptome-wide association in lung tissue revealed that high expression of the monocyte-macrophage chemotactic receptor CCR2 is associated with severe COVID-19. Our results identify robust genetic signals relating to key host antiviral defence mechanisms and mediators of inflammatory organ damage in COVID-19. Both mechanisms may be amenable to targeted treatment with existing drugs. However, large-scale randomized clinical trials will be essential before any change to clinical practice
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