94 research outputs found
Crown morphometry for Quercus crassifolia Humb. & Bonpl. and Quercus rugosa Née in Hidalgo, Mexico
Quercus crassifolia y Quercus rugosa son especies de importancia ecológica y económica por su distribución geográfica, intervalo altitudinal, abundancia en regiones montañosas y plasticidad. Sin embargo, la gestión y aprovechamiento forestal han sido incompatibles con las necesidades ecológicas de cada especie de Quercus, en parte por la falta de herramientas silvícolas cuantitativas. Por tal motivo, se plantearon los objetivos de i) determinar los índices morfométricos (IM) y su correlación con el diámetro normal (dn), altura total (At), diámetro de copa (dc) y altura de fuste limpio (Afl); y ii) ajustar con Modelos de Efectos Mixtos (MEM), las características de la copa de Quercus crassifolia y Quercus rugosa en función del dn, con la inclusión de la covariable altitud. Con información dasométrica de 128 sitios de muestreo distribuidos en 32 conglomerados en bosques de clima templado del estado de Hidalgo, se calcularon y correlacionaron ocho IM mediante el coeficiente de Pearson. Además, se ajustaron con MEM los modelos de Schumacher, Alométrico y Lineal para estimar el dc, área de proyección de copa (Apc) y proporción de la copa en porcentaje (pc%), respectivamente. Para Quercus crassifolia, por cada metro que crece el radio de copa se tiene un incremento de 8,8 cm en dn, mientras que en Quercus rugosa el aumento es de 9,8 cm. El índice de esbeltez promedio es de 0,53 y 0,51, respectivamente. La correlación de Pearson entre variables dasométricas e IM con la forma de copa fue de -0,61 y para la altura total, Apc, dc y pc% con el dn resulto >0,64, ambos para las dos especies. Los MEM fueron estadísticamente robustos y sin violaciones de los supuestos de regresión. La información silvícola generada puede ser referencia para planear las actividades de gestión y monitoreo en los rodales Quercus crassifolia y Quercus rugosa.Quercus crassifolia and Quercus rugosa are species of ecological and economic importance due to their geographical distribution, altitudinal range, abundance in mountainous regions, and plasticity. However, forest management and exploitation have proven incompatible with the ecological needs of each Quercus species, partly due to the lack of quantitative silvicultural tools. For this reason, the following objectives were established i) to determine the morphometric indices (MI) and their correlation with the normal diameter (dn), total height (At), crown diameter (dc) and clean stem height (Afl); and ii) to adjust with Mixed Effects Models (MEM), the characteristics of the Quercus crassifolia and Quercus rugosa crown as a function of dn, with the inclusion of the altitude covariate. With dasometric information from 128 sampling sites distributed in 32 clusters in temperate climate forests of the state of Hidalgo, eight MI were calculated and correlated using the Pearson coefficient. In addition, the Schumacher, Allometric and Linear models were adjusted with MEM to estimate the dc, crown projection area (Apc), and crown proportion in percentage (pc%), respectively. For Quercus crassifolia, for every meter that the crown radius grows there is an increase of 8.8 cm in dn, while in Quercus rugosa the increase is 9.8 cm. The average slenderness index is 0.53 and 0.51, respectively. The Pearson correlation between dasometric variables and MI with the cup shape was -0.61 and for the total height, Apc, dc and pc% with the dn it was >0.64, both for the two species. The MEMs were statistically robust and without violations of the regression assumptions. The silvicultural information generated can be a reference to plan management and monitoring activities in the Quercus crassifolia and Quercus rugosa stands
Integrated land and water-borne geophysical surveys shed light on the sudden drying of large karst lakes in southern Mexico
Karst water resources play an important role in drinking water supply but are highly vulnerable to even slight changes in climate. Thus, solid and spatially dense geological information is needed to model the response of karst hydrological systems to such changes. Additionally, environmental information archived in lake sediments can be used to understand past climate effects on karst water systems. In the present study, we carry out a multi-methodological geophysical survey to investigate the geological situation and sedimentary infill of two karst lakes (Metzabok and Tzibaná) of the Lacandon Forest in Chiapas, southern Mexico. Both lakes present large seasonal lake-level fluctuations and experienced an unusually sudden and strong lake-level decline in the first half of 2019, leaving Lake Metzabok (maximum depth ∼25 m) completely dry and Lake Tzibaná (depth ∼70 m) with a water level decreased by approx. 15 m. Before this event, during a lake-level high stand in March 2018, we collected water-borne seismic data with a sub-bottom profiler (SBP) and transient electromagnetic (TEM) data with a newly developed floating single-loop configuration. In October 2019, after the sudden drainage event, we took advantage of this unique situation and carried out complementary measurements directly on the exposed lake floor of Lakes Metzabok and Tzibaná. During this second campaign, we collected time-domain induced polarization (TDIP) and seismic refraction tomography (SRT) data. By integrating the multi-methodological data set, we (1) identify 5–6 m thick, likely undisturbed sediment sequences on the bottom of both lakes, which are suitable for future paleoenvironmental drilling campaigns, (2) develop a comprehensive geological model implying a strong interconnectivity between surface water and karst aquifer, and (3) evaluate the potential of the applied geophysical approach for the reconnaissance of the geological situation of karst lakes. This methodological evaluation reveals that under the given circumstances, (i) SBP and TDIP phase images consistently resolve the thickness of the fine-grained lacustrine sediments covering the lake floor, (ii) TEM and TDIP resistivity images consistently detect the upper limit of the limestone bedrock and the geometry of fluvial deposits of a river delta, and (iii) TDIP and SRT images suggest the existence of a layer that separates the lacustrine sediments from the limestone bedrock and consists of collapse debris mixed with lacustrine sediments. Our results show that the combination of seismic methods, which are most widely used for lake-bottom reconnaissance, with resistivity-based methods such as TEM and TDIP can significantly improve the interpretation by resolving geological units or bedrock heterogeneities, which are not visible from seismic data. Only the use of complementary methods provides sufficient information to develop comprehensive geological models of such complex karst environment
Quantic Analysis of Formation of a Biomaterial of Latex, Retinol, and Chitosan for Biomedical Applications
The present work shows the quantum theoretical analysis and practical tests for the formation of a homogeneous mixture with Latex (Lx), Chitosan (Qn) and Retinol (Rl), which work as possible biomaterial for regeneration of epithelial tissue. Lx, Qn, and Rl compounds molecules were designed through Hyperchem to get the coefficient of electrostatic potential calculations. The amounts used to create the biomaterial are minimum depending on the quantities of molecules used in chemical design. A positive calculation was obtained for the reaction of these three compounds and the formation of the biomaterial in physical checking theory etc
Quantic Analysis of the Adherence of a Gram-Negative Bacteria in A HEPA Filter
It is known that Gram-negative bacteria (GNB) are the most frequent bacteria in hospital units. It is also known that GNBs generate a greater number of nosocomial infections in critical areas. In the present work, the adhesion of the bacterial cell wall (BCW) to the compounds of the material layers of a high efficiency filter (HEPA) was analyzed. The analysis was carried out by means of molecular simulation and quantum chemistry. The BCW and HEPA molecules were designed using Hyperchem software for simulation. The calculations of the quantum interactions of the molecules were carried out using the theory of the electron transfer coefficient (ETC). It obtained from 4 to 6 compounds that are more likely to interact even as a chemical reaction. The compounds of the glass fibers are the ones that work best for the adhesion and destruction of the BCW
Association of rs712 polymorphism in a let-7 microRNA-binding site of KRAS gene with colorectal cancer in a Mexican population
Objective(s): The rs712 polymorphism in a let-7 microRNA-binding site at KRAS gene has been associated with cancer. To examine its association with rs712 polymorphism, we analyzed Mexican individuals with colorectal cancer (CRC) and healthy subjects. Materials and Methods: Genotyping of the rs712 polymorphism was performed by polymerase chain reaction in 281 controls and 336 CRC patients. Results: The observed frequencies of rs712 polymorphism indicated an associated protective factor for CRC (P=0.032). An association between genotype and the disease was evident in: colon localization (allele T, odds ratio (OR) 3.82, 95% confidence Intervals (CI) 2.77-5.28, P=0.0001), node metastasis (genotype TT, OR 2.49, 95% CI 1.45-4.28, P=0.0009), poor differentiation (genotype GT, OR 2.35, 95% CI 1.35-4.1, P=0.0033), and poor chemotherapy response (genotype GT, OR 2.6, 95% CI 1.7-4.24, P=0.0001). Conclusion: Comparison of the data from patients with control group showed that polymorphism of rs712 in KRAS gene was protective factor, which was associated with susceptibility for CRC. However, the genotypes TT and GT of rs712 polymorphism in KRAS could contribute significantly to colon localization, node metastasis, poor differentiation and poor chemotherapy response in CRC patients in this sample population
[EFFECT OF HERBAL ADDITIVE ON THE APPEARING DIGESTIBILITY OF THE DRY MATTER OF HOLSTEIN CALVES
El objetivo del presente trabajo fue evaluar la dosificación de 0.0, 2.0, 3.0 y 4.0 g d-1 en la alimentación de un aditivo herbal conformada por (Withania somnifera, Ocimum sanctum, Tinospora cordifolia y Emblica officinalis) de becerras Holstein sobre la digestibilidad aparente. Se emplearon 40 becerras de la raza Holstein de 20 a 25 días de edad (peso inicial 43.35 ± 2.41 kg), los animales fueros distribuidos aleatoriamente en corrales individuales equipados con comederos y bebederos. La dosificación del aditivo herbal fue mediante la administración oral, durante 67 días. Se colectaron muestras de heces, a los días 50-55 del experimento, de cada una de las becerras para determinar la digestibilidad aparente de la materia seca. La dosificación del aditivo herbal no modifico (p > 0.05) la digestibilidad aparente de la materia seca, sin embargo, presento una tendencia creciente con la adición de 2, 3 y 4 g d-1 del aditivo herbal aumentando 7.27, 8.02 y 4.86 %, respectivamente, con respecto a la dieta control. Por lo tanto, el empleo de 2.51 g d-1 de un aditivo herbal puede utilizarse como alternativa en la alimentación de becerras mejorando la digestibilidad aparente de la materia seca, optimizando el estado nutricional en la cría de becerras.Proyecto financiado por Techno Fedd Méxic
Mollicutes antibiotic resistance profile and presence of genital abnormalities in couples attending an infertility clinic.
OBJECTIVE: The present study aimed to identify Mollicutes infection in the reproductive system. We also examined the microbiological, biochemical, and antimicrobial profiles of Mollicutes infection, which are potentially associated with clinical reproductive abnormalities causing infertility in couples. METHODS: Thirty-seven couples who were attending an infertility clinic were enrolled. Detection of genital mycoplasmas was performed in cervicovaginal samples or male urethral swabs. Microbiological culture and biochemical and antimicrobial profiles were characterized using a Mycoplasma kit. The results were associated with reproductive abnormalities, as assessed by medical specialists from the infertility clinic. RESULTS: Up to 28.3% of all biological samples (n = 74) showed positive cultures. Bacterial isolates were Ureaplasma urealyticum (71.4%), Mycoplasma hominis (9.5%), or coinfections (19%). Most Mollicutes showed significant resistance to fluoroquinolones, macrolides, and tetracycline; and showed susceptibility to doxycycline, josamycin, and pristinamycin. The presence of resistant strains to any antibiotic was significantly associated with genital abnormalities (χ2 test, relative risk = 11.38 [95% confidence interval: 5.8-22.9]), particularly in women. The highest statistical association was found for macrolide-resistant strains. CONCLUSION: The microbiological antibiotic resistance profile is epidemiologically associated with abnormalities of the reproductive system in couples attending an infertility clinic
Molecular approaches to trematode systematics: 'best practice' and implications for future study
To date, morphological analysis has been the cornerstone to trematode systematics. However, since the late-1980s we have seen an increased integration of genetic data to overcome problems encountered when morphological data are considered in isolation. Here, we provide advice regarding the ‘best molecular practice’ for trematode taxonomy and systematic studies, in an attempt to help unify the field and provide a solid foundation to underpin future work. Emphasis is placed on defining the study goals and recommendations are made regarding sample preservation, extraction methods, and the submission of molecular vouchers. We advocate generating sequence data from all parasite species/host species/geographic location combinations and stress the importance of selecting two independently evolving loci (one ribosomal and one mitochondrial marker). We recommend that loci should be chosen to provide genetic variation suitable to address the question at hand and for which sufficient ‘useful’ comparative sequence data already exist. Quality control of the molecular data via using proof-reading Taq polymerase, sequencing PCR amplicons using both forward and reverse primers, ensuring that a minimum of 85% overlap exists when constructing consensus sequences, and checking electropherograms by eye is stressed. We advise that all genetic results are best interpreted using a holistic biological approach, which considers morphology, host identity, collection locality, and ecology. Finally, we consider what advances next-generation sequencing holds for trematode taxonomy and systematics
Gamificación en Iberoamérica. Experiencias desde la comunicación y la educación
La presente obra capitular es el resultado de las investigaciones sobre las aplicaciones de la gamificación en contextos múltiples, emergentes provenientes de las comunicaciones presentadas en el Simposio 06 del III Congreso Internacional Comunicación y Pensamiento (Sevilla, España), así como de aquellas presentadas por los miembros del Gamelab UPS, del Proyecto I+D+i Coordinado “Competencias mediáticas de la ciudadanía en medios digitales emergentes (smartphones y tablets): Prácticas innovadoras y estrategias educomunicativas en contextos múltiples” (EDU2015-64015-C3-1-R) (MINECO/FEDER), de la “Red de Educación Mediática” del Programa Estatal de Investigación Científica-Técnica de Excelencia, Subprograma Estatal de Generación de Conocimiento (EDU2016-81772-REDT), financiados por el Fondo Europeo de Desarrollo Regional (FEDER) y Ministerio de Economía y Competitividad de España.
En este sentido se busca construir, desde una mirada dual desde Europa y América Latina el primer libro iberoamericano de gamificación, avalado por el Gamelab de la Universidad Politécnica Salesiana (Ecuador), el Proyecto I+D+i EDU2015-64015-C3-1-R, la Red Interuniversitaria Euroamericana de Investigación sobre Competencias Mediáticas para la Ciudadanía (Alfamed), el Laboratorio de Estudios en Comunicación (Ladecom) y el Grupo de Investigación Ágora (PAI-HUM-648) de la Universidad de Huelva (España) y el Grupo de Investigación Estructura, Historia y Contenidos de la Comunicación GREHCCO
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