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The destructive and empirical methods commonly used to estimate carbon pools in forests managed timber are time-consuming, expensive and unfeasible at a large scale; satellite images allow evaluations at different scales, reducing time and costs. The objective of this study was to evaluate the tree biomass (TB) and carbon content (CC) through satellite images derived from Sentinel 2 in underutilized stands in southern Mexico. In 2022, 12 circular sites of 400 m2 with four silvicultural treatments (STs) were established in a targeted manner: 1st thinning (T1), free thinning (FT), regeneration cut (RC) and unmanaged area (UA). A tree inventory was carried out, and samples were obtained to determine their TB based on specific gravity and CC through the Walkey and Black method. The satellite image of the study area was downloaded from Sentinel 2 to fit a simple linear model as a function of the Normalized Difference Vegetation Index (10 m pixel-1) showing significance (p ≤ 0.01) and a adjusted R2 = 0.92. Subsequently, the TB and CC (t ha-1) were estimated for each ST and managed area. The total managed area (3,201 ha-1) had 126 t TB ha-1 and 57 t C ha-1. Of the areas with STs, the area with FT showed the highest accumulation of TB (140 t ha-1) and C (63 t ha-1) without showing differences (p > 0.05) with respect to those of the UA, which presented 129 t TB ha-1 and 58 t C ha-1. The satellite images from Sentinel 2 provide reliable estimates of the amounts of TB and CC in the managed stands. Therefore, it can be concluded that an adequate application of STs maintains a balance in the accumulation of tree C.
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Pinus , Quercus , Carbono , México , Florestas , ÁrvoresRESUMO
Contamination of food chains by toxigenic fungi and aflatoxins is a global problem that causes damage to human health, as well as to crop and livestock production. The objective is to evaluate Aspergillus flavus and total aflatoxins (AFs) occurrence in totally mixed rations (TMRs) for dairy cows and aflatoxin M1 (AFM1) in milk for human consumption. Ninety-nine dairy production units located in Aguascalientes, Mexico, were randomly selected, and samples were collected from TMRs, raw milk, and milk marketed in the city in two consecutive agricultural cycles. AFs were quantified in TMRs and milk by indirect enzyme immunoassay and HPLC; aflatoxigenic and molecular (PCR) capacity of monosporic A. flavus isolates in the feed was characterized. All feed, raw, and pasteurized milk samples showed aflatoxin contamination (26.0 ± 0.4 µg/kg, 32.0 ± 1.0, and 31.3 ± 0.7 ng/L, respectively), and a significant proportion (90.4, 11.3, and 10.3%) exceeded the locally applied maximum permissible limits for feed and milk (20.0 µg/kg and 50 ng/L). Aflatoxin contamination in both TMRs and milk indicated a seasonal influence, with a higher concentration in the autumn-winter cycle when conditions of higher humidity prevail. The results obtained suggest the existence of contamination by aflatoxigenic A. flavus and aflatoxins in the diet formulated for feeding dairy cows and, consequently, in the dairy food chain of this region of the Mexican Highland Plateau.
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Aflatoxina M1 , Aflatoxinas , Aflatoxina M1/análise , Aflatoxinas/análise , Animais , Aspergillus flavus , Bovinos , Feminino , México , Leite/químicaRESUMO
Ethers can be found in the environment as structural, active or even pollutant molecules, although their degradation is not efficient under environmental conditions. Fungal unspecific heme-peroxygenases (UPO were reported to degrade low-molecular-weight ethers through an H2O2-dependent oxidative cleavage mechanism. Here, we report the oxidation of a series of structurally related aromatic ethers, catalyzed by a laboratory-evolved UPO (PaDa-I) aimed at elucidating the factors influencing this unusual biochemical reaction. Although some of the studied ethers were substrates of the enzyme, they were not efficiently transformed and, as a consequence, secondary reactions (such as the dismutation of H2O2 through catalase-like activity and suicide enzyme inactivation) became significant, affecting the oxidation efficiency. The set of reactions that compete during UPO-catalyzed ether oxidation were identified and quantified, in order to find favorable conditions that promote ether oxidation over the secondary reactions.
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BACKGROUND: Conducting research during specialty training provides an opportunity to develop critical thinking and leadership skills along with a better understanding of the scientific literature. However, trainees often find it difficult to undertake research, in the context of labor-intensive surgical training. The aim of this study is to evaluate the research output and limitations of plastic surgery residents in different countries. METHODS: An international cross-sectional study involving plastic surgery trainees and recent postgraduates from Brazil, Chile, Germany, and the United Kingdom was conducted. A survey inquiring into academic productivity, limitations to conducting research, and working-hours patterns was distributed among eligible participants. RESULTS: From September to December 2019, 106 surveys were retrieved. Most respondents declared having participated in at least 1 project that resulted in a presentation or publication during their training (90.6% in national presentations, 68% international presentations, 67% in national publications, and 66% international publications). Having completed a previous research fellowship was associated with a statistically higher academic output (P < 0.05). Seventy-nine percent of respondents felt that their participation in research activities would have been greater if limiting factors had been addressed, including lack of time (72.5%) and insufficient supervision and mentoring (55%). CONCLUSIONS: Optimizing plastic surgery trainees' participation in scientific research is beneficial both for residents and their mentors. Research fellowships can provide an opportunity for academically oriented trainees to further develop their research skills. Protected time and adequate mentoring can help not only to increase residents' research output, but also to recruit the next generation of academic plastic surgeons.
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Internato e Residência , Cirurgia Plástica , Estudos Transversais , Bolsas de Estudo , Humanos , Mentores , Cirurgia Plástica/educação , Inquéritos e QuestionáriosRESUMO
El mindfulness es una práctica meditativa que ha probado disminuir el estrés psicofisiológico. Propósito: analizar, si el mindfulness es efectivo para disminuir el estrés psicofisiológico, en deportistas de alto rendimiento en temporada competitiva. Se realizó una búsqueda de estudios clínicos que incluyeran diferentes técnicas meditativas para la reducción del estrés en deportistas durante la fase competitiva. En PubMed, Scopus y Web of Science (1985 al 10 de agosto del 2019), se buscaron las combinaciones de palabras mindfulness, meditation, yoga, sport, athlete, intervention, stress, cortisol. Se localizaron sólo siete trabajos, tres de ellos con información cuantitativa, un cuantitativo y tres de metodología mixta. En los siete estudios encontrados (153 sujetos; 134 hombres y 19 mujeres) sus autores mencionan que el mindfulness fue efectivo para la reducción del estrés en los atletas durante la etapa competitiva.
Mindfulness is a meditative practice that has proven to reduce psycho-physiological stress. Purpose: Analyze if mindfulness is effective to reduce psycho-physiological stress in athletes during their competitive season. Clinical studies that included different meditative techniques for stress reduction in athletes during the competitive phase was searched for in databases such as PubMed, Scopus and Web of Science (1985 to August 10, 2019), using the combinations of the words mindfulness, meditation, yoga, sport, athlete, intervention, stress, and cortisol. Only seven papers were located, three of them with a quantitative design, one as quantitative and three with mixed methodology. In the seven studies found (153 subjects; 134 men and 19 women) their authors mention that mindfulness was effective for reducing stress in athletes during the competitive season.
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Humanos , Esportes , Estresse Psicológico/prevenção & controle , Terapia de Relaxamento , Atenção Plena , Estresse FisiológicoRESUMO
Unspecific peroxygenases (UPOs) are fungal heme-thiolate enzymes able to catalyze a wide range of oxidation reactions, such as peroxidase-like, catalase-like, haloperoxidase-like, and, most interestingly, cytochrome P450-like. One of the most outstanding properties of these enzymes is the ability to catalyze the oxidation a wide range of organic substrates (both aromatic and aliphatic) through cytochrome P450-like reactions (the so-called peroxygenase activity), which involves the insertion of an oxygen atom from hydrogen peroxide. To catalyze this reaction, the substrate must access a channel connecting the bulk solution to the heme group. The composition, shape, and flexibility of this channel surely modulate the catalytic ability of the enzymes in this family. In order to gain an understanding of the role of the residues comprising the channel, mutants derived from PaDa-I, a laboratory-evolved UPO variant from Agrocybe aegerita, were obtained. The two phenylalanine residues at the surface of the channel, which regulate the traffic towards the heme active site, were mutated by less bulky residues (alanine and leucine). The mutants were experimentally characterized, and computational studies (i.e., molecular dynamics (MD)) were performed. The results suggest that these residues are necessary to reduce the flexibility of the region and maintain the topography of the channel.
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Agrocybe/enzimologia , Domínio Catalítico , Oxigenases de Função Mista/química , Fenilalanina/química , Saccharomyces cerevisiae/metabolismo , Biocatálise , Heme/química , Peróxido de Hidrogênio/química , Oxigenases de Função Mista/genética , Simulação de Dinâmica Molecular , Mutagênese Sítio-Dirigida/métodos , Mutação , Saccharomyces cerevisiae/genéticaRESUMO
Some carnivorous mammals ingest fruit and disperse seeds of forest plant species capable of colonizing disturbed areas in ecosystems. The objective of the present study was to evaluate the dissemination of Arctostaphylos pungens and Juniperus deppeana seeds by the gray fox (Urocyon cinereoargenteus), coyote (Canis latrans), and other carnivores in the Protected Natural Area Sierra Fría, in Aguascalientes, Mexico. Scat collection was undertaken via transects using the direct search method, while the seasonal phenology of A. pungens and J. deppeana was evaluated by recording flower and fruit abundance on both the plant and the surrounding forest floor ground. Seed viability was assessed by optical densitometry via X-ray and a germination test. It was found that the gray fox, coyote, ringtail (Bassariscus astutus), and bobcat (Lynx rufus) disseminated seeds of A. pungens (212 ± 48.9 seeds/scat) and J. deppeana (23.6 ± 4.9 seeds/scat), since a large proportion of the collected scat of these species contained seeds (28/30 = 93.33%, 12/43 = 27.9%, 6/12 = 50% and 7/25 = 28% respectively). The gray fox, coyote, ringtail, and bobcat presented an average of seed dispersion of both plant species of 185.4 ± 228.7, 4.0 ± 20.0, 12.1 ± 30.4, and 0.8 ± 1.5 per scat; the seed proportions in the gray fox, coyote, ringtail, and bobcat were 89.6/10.4%, 82.3/17.7%, 90.4/9.6%, and 38.1/61.9% for A. pungens and J. deppeana, respectively. The phenology indicated a finding related to the greater abundance of ripe fruit in autumn and winter (p < .01). This coincided with the greater abundance of seeds found in scats during these seasons. Endozoochory and diploendozoochory enhanced the viability and germination of the seeds (p > .05), except in those of A. pungens dispersed by coyote. These results suggest that carnivores, particularly the gray fox, the coyote, and the bobcat, play an important role in forest seed dissemination, and thus forest regeneration, by making both a quantitative and qualitative contribution to the dispersal of the two pioneer species under study.
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INTRODUCCIÓN: La ascitis quilosa es la presencia de líquido linfático en la cavidad peritoneal. Como consecuencia de una cirugía abdominal es muy infrecuente, encontrando 5 casos previos en la literatura revisada tras colecistectomía. OBJETIVO: Presentar un caso clínico de ascitis quilosa poscolecistectomía, su manejo y una revisión de la literatura. MATERIALES Y MÉTODOS: Varón de 77 años, quiloperitoneo 21 días después de realización de colecistectomía programada por colecistitis aguda. Resultados: Se realiza drenaje percutáneo con débito de 5 L en 24 horas, se inicia octreótido subcutáneo y nutrición parenteral total. Al tercer día disminuye el débito por el drenaje, por lo que se inicia dieta rica en triglicéridos de cadena media con buena evolución posterior. De los 5 casos previos tras colecistectomía, el 60% se resolvió con tratamiento conservador, un paciente precisó reintervención y otro colocación de un shunt portosistémico intrahepático trasnyugular (TIPSS). CONCLUSIÓN: La ascitis quilosa es una complicación postquirúrgica infrecuente, encontrando solo 5 casos previos tras colecistectomía. Inicialmente el manejo debe ser conservador, en caso de persistencia se deben valorar otras medidas.
INTRODUCTION: Chylous ascites is defined as the presence of lymph fluid in the peritoneal cavity. It is a rare complication after abdominal surgery; only 5 previously reported cases were found after cholecystectomy. Aim: Present a case report and a literature review. MATERIALS AND METHOD: Case report of a 77 year old male who underwent an elective cholecystectomy due to acute cholecystitis. Chyloperitoneum showed up 21 days after surgery. RESULTS: We performed a percutaneous drainage and 5 L of fluid were removed in 24 hours. We started treatment with subcutaneous Octreotide and total parenteral nutrition. After 3 days drain output decreased and we started a medium-chain triglycerides diet with good progress. The outcome of 60% of the 5 previous case reports of chyloperitoneum after cholecystitis, were successful with conservative management, surgical intervention was needed in one patient and a transjugular intrahepatic portosystemic shunt (TIPSS) was placed in another patient. CONCLUSION: Chylous ascites is a rare complication after surgery, there are only 5 previously case reports after cholecystectomy. Conservative management has to be the first option and in case of persistence another therapy has to be considered.
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Humanos , Masculino , Idoso , Ascite Quilosa/cirurgia , Ascite Quilosa/etiologia , Colecistectomia Laparoscópica/efeitos adversos , Drenagem , Ascite Quilosa/diagnóstico por imagem , Colecistite Aguda/cirurgiaRESUMO
Large wildfires can cover millions of hectares of forest every year worldwide, causing losses in ecosystems and assets. Fire simulation and modeling provides an analytical scheme to characterize and predict fire behavior and spread in several and complex environments. Spatial dynamics of large wildfires can be analyzed using satellite active fire data, a cost-effective way to acquire information systematically worldwide. The simulated growth of three large wildland fires from the USA, Chile and Spain with different fire spread pattern, duration and size has been compared to satellite active fire data. Additionally, a new approach to reinitialize fire simulations in near real-time and predict a more accurate fire spread is shown in this work. Discrepancies between the simulated fire growth and satellite active data were measured spatially and temporally in the three fires, increasing along the fire duration. The reinitialization approach meaningfully improved the accuracy of fire simulations in all case studies. Satellite active fire data showed a high potential to be used in real fire incidents, improving fire monitoring and simulation and, therefore, supporting the decision-making process of the fire analyst. The reinitialization approach could be applied by using the current satellite active fire data such as MODIS or VIIRS as well as Unmanned Aerial Vehicles or GPS locations from suppression resources.
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Incêndios , Incêndios Florestais , Chile , Ecossistema , EspanhaRESUMO
In this work, we sought to obtain a more stable laccase with higher operational stability for the oxidation of phenols. During this reaction, phenoxy free radicals are produced that gradually inactivate the enzyme; the inactivation rate depends on the phenol chemical nature. In order to predict residues prone to oxidize within the active site, we simulated activated states of the catalytic region of a fungal laccase using QM-MM tools (Quantum Mechanics-Molecular Mechanics). After simulating the electron distribution in both the basal and activated state (plus or minus one electron) of several conformations of Coriolopsis gallica laccase, residues that could be susceptible to oxidation were identified, according to the values of spin density obtained from calculations. Three targets were selected (F357, F413, and F475) to be replaced by site-directed mutagenesis with less oxidizable residues such as leucine, alanine, and isoleucine. The resulting variants displayed a higher specific activity (from 1.5-to 4-fold) than the parental enzyme. Catalyst depletion during phenol oxidation was 2.5-fold lower for the variants, reflecting a higher operational stability.