51 research outputs found

    Estimating Stand and Fire-Related Surface and Canopy Fuel Variables in Pine Stands Using Low-Density Airborne and Single-Scan Terrestrial Laser Scanning Data

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    In this study, we used data from a thinning trial conducted on 34 different sites and 102 sample plots established in pure and even-aged Pinus radiata and Pinus pinaster stands, to test the potential use of low-density airborne laser scanning (ALS) metrics and terrestrial laser scanning (TLS) metrics to provide accurate estimates of variables related to surface and canopy fires. An exhaustive field inventory was carried out in each plot to estimate the main stand variables and the main variables related to fire hazard: surface fuel loads by layers, fuel strata gap, surface fuel height, stand mean height, canopy base height, canopy fuel load and canopy bulk density. In addition, the point clouds from low-density ALS and single-scan TLS of each sample plot were used to calculate metrics related to the vertical and horizontal distribution of forest fuels. The comparative performance of the following three non-parametric machine learning techniques used to estimate the main stand- and fire-related variables from those metrics was evaluated: (i) multivariate adaptive regression splines (MARS), (ii) support vector machine (SVM), and (iii) random forest (RF). The selection of the best modeling approach was based on a comparison of the root mean square error (RMSE), obtained by optimizing the parameters of each technique and performing cross-validation. Overall, the best results were obtained with the MARS techniques for data from both sensors. The TLS data provided the best results for variables associated with the internal characteristics of canopy structure and understory fuel but were less reliable for estimating variables associated with the upper canopy, due to occlusion by mid-canopy foliage. The combination of ALS and TLS metrics improved the accuracy of estimates for all variables analyzed, except the height and the biomass of the understory shrubs. The variability demonstrated by the combined use of both types of metrics ranged from 43.11% for the biomass of duff litter layers to 94.25% for dominant height. The results suggest that the combination of machine learning techniques and metrics derived from low-density ALS data, drawn from a single-scan TLS or a combination of both metrics, may represent a promising alternative to traditional field inventories for obtaining valuable information about surface and canopy fuel variables at large scalesinfo:eu-repo/semantics/publishedVersio

    Estimating Stand and Fire-Related Surface and Canopy Fuel Variables in Pine Stands Using Low-Density Airborne and Single-Scan Terrestrial Laser Scanning Data

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    [EN] In this study, we used data from a thinning trial conducted on 34 different sites and 102 sample plots established in pure and even-aged Pinus radiata and Pinus pinaster stands, to test the potential use of low-density airborne laser scanning (ALS) metrics and terrestrial laser scanning (TLS) metrics to provide accurate estimates of variables related to surface and canopy fires. An exhaustive field inventory was carried out in each plot to estimate the main stand variables and the main variables related to fire hazard: surface fuel loads by layers, fuel strata gap, surface fuel height, stand mean height, canopy base height, canopy fuel load and canopy bulk density. In addition, the point clouds from low-density ALS and single-scan TLS of each sample plot were used to calculate metrics related to the vertical and horizontal distribution of forest fuels. The comparative performance of the following three non-parametric machine learning techniques used to estimate the main stand-and fire-related variables from those metrics was evaluated: (i) multivariate adaptive regression splines (MARS), (ii) support vector machine (SVM), and (iii) random forest (RF). The selection of the best modeling approach was based on a comparison of the root mean square error (RMSE), obtained by optimizing the parameters of each technique and performing crossvalidation. Overall, the best results were obtained with the MARS techniques for data from both sensors. The TLS data provided the best results for variables associated with the internal characteristics of canopy structure and understory fuel but were less reliable for estimating variables associated with the upper canopy, due to occlusion by mid-canopy foliage. The combination of ALS and TLS metrics improved the accuracy of estimates for all variables analyzed, except the height and the biomass of the understory shrubs. The variability demonstrated by the combined use of both types of metrics ranged from 43.11% for the biomass of duff litter layers to 94.25% for dominant height. The results suggest that the combination of machine learning techniques and metrics derived from low-density ALS data, drawn from a single-scan TLS or a combination of both metrics, may represent a promising alternative to traditional field inventories for obtaining valuable information about surface and canopy fuel variables at large scalesSIThis research was funded by the projects GEPRIF (RTA2014-00011-C06-04) and VIS4FIRE (RTA2017-00042-C05-05) of the Spanish Ministry of Economy, Industry, and Competitiveness and a pre-doctoral grant of the first author funded by the “Consejería de Educación, Universidad y Formación Profesional” and the “Consejería de Economía, Empleo e Industria” of the Galician Government and the EU operational program “FSE Galicia 2014–2020”

    Novel PITX2 Homeodomain-Contained Mutations from ATRIAL Fibrillation Patients Deteriorate Calcium Homeostasis

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    Atrial fibrillation (AF) is the most common cardiac arrhythmia in the human population, with an estimated incidence of 1¿2% in young adults but increasing to more than 10% in 80+ years patients. Pituitary Homeobox 2, Paired Like Homeodomain 2 (PITX2c) loss-of-function in mice revealed that this homeodomain (HD)-containing transcription factor plays a pivotal role in atrial electrophysiology and calcium homeostasis and point to PITX2 as a candidate gene for AF. To address this issue, we recruited 31 AF patients for genetic analyses of both the known risk alleles and PITX2c open reading frame (ORF) re-sequencing. We found two-point mutations in the homedomain of PITX2 and three other variants in the 5¿untranslated region. A 65 years old male patient without 4q25 risk variants but with recurrent AF displayed two distinct HD-mutations, NM_000325.5:c.309G>C (Gln103His) and NM_000325.5:c.370G>A (Glu124Lys), which both resulted in a change within a highly conserved amino acid position. To address the functional impact of the PITX2 HD mutations, we generated plasmid constructs with mutated version of each nucleotide variant (MD4 and MD5, respectively) as well as a dominant negative control construct in which the PITX2 HD was lacking (DN). Functional analyses demonstrated PITX2c MD4 and PITX2c MD5 decreased Nppa-luciferase transactivation by 50% and 40%, respectively, similar to the PITX2c DN (50%), while Shox2 promoter repression was also impaired. Co-transactivation with other cardiac-enriched co-factors, such as Gata4 and Nkx2.5, was similarly impaired, further supporting the pivotal role of these mutations for correct PITX2c function. Furthermore, when expressed in HL1 cardiomyocyte cultures, the PITX2 mutants impaired endogenous expression of calcium regulatory proteins and induced alterations in sarcoplasmic reticulum (SR) calcium accumulation. This favored alternating and irregular calcium transient amplitudes, causing deterioration of the beat-to-beat stability upon elevation of the stimulation frequency. Overall this data demonstrate that these novel PITX2c HD-mutations might be causative of atrial fibrillation in the carrier.This work was supported by grants from The Spanish Ministry of Science Innovation and Universities [SAF2017-88019-C3-1-R] to L.H.-M. V.J.-S. was employed by CIBERCV [RD12/0042/0002] grant. Work was also supported by a PhD scholarship [FPU18/01250] to S.C., and partially funded by grants from Generalitat de Catalunya [SGR2017-1769] and Fundació Marato TV3 [20152030] to L.H.-M., a translational CNIC grant [2009/08] to D.F., R.C. and L.H.-M. and a grant-in-aid from the Junta de Andalucia Regional Council to D.F. and A.A. [CTS-446]

    Discovery and validation of an NMR-based metabolomic profile in urine as TB biomarker

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    Despite efforts to improve tuberculosis (TB) detection, limitations in access, quality and timeliness of diagnostic services in low- and middle-income countries are challenging for current TB diagnostics. This study aimed to identify and characterise a metabolic profile of TB in urine by high-field nuclear magnetic resonance (NMR) spectrometry and assess whether the TB metabolic profile is also detected by a low-field benchtop NMR spectrometer. We included 189 patients with tuberculosis, 42 patients with pneumococcal pneumonia, 61 individuals infected with latent tuberculosis and 40 uninfected individuals. We acquired the urine spectra from high and low-field NMR. We characterised a TB metabolic fingerprint from the Principal Component Analysis. We developed a classification model from the Partial Least Squares-Discriminant Analysis and evaluated its performance. We identified a metabolic fingerprint of 31 chemical shift regions assigned to eight metabolites (aminoadipic acid, citrate, creatine, creatinine, glucose, mannitol, phenylalanine, and hippurate). The model developed using low-field NMR urine spectra correctly classified 87.32%, 85.21% and 100% of the TB patients compared to pneumococcal pneumonia patients, LTBI and uninfected individuals, respectively. The model validation correctly classified 84.10% of the TB patients. We have identified and characterised a metabolic profile of TB in urine from a high-field NMR spectrometer and have also detected it using a low-field benchtop NMR spectrometer. The models developed from the metabolic profile of TB identified by both NMR technologies were able to discriminate TB patients from the rest of the study groups and the results were not influenced by anti-TB treatment or TB location. This provides a new approach in the search for possible biomarkers for the diagnosis of TB

    Revisión de 13 especies de la familia Triatominae (Hemiptera: Reduviidae) vectores de la enfermedad de Chagas, en México

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    Vectors of Trypanosoma cruzi, parasite responsible for Chagas disease, are divided in intradomestic, peridomestic andsylvatic. The intradomestic are Triatoma barberi and Triatoma dimidiata, two species that represent the highest healthrisk among the Mexican population. Triatoma dimidiata is a species found mainly inside human habitats, but inYucatan, it corresponds to the peridomicile vectors. Also in the peridomicile most of Chagas disease vectors arefound: Meccus bassolsae, M. longipennis, M. mazzottii, M pallidipennis, M. phyllosomus, M picturata, Triatomagerstaeckeri, T mexicana, T rubida, Dipetalogaster máxima (the last two are in the process of becoming adapted tothe domicile), Panstrongylus rufotuberculatus which occasionally enters the domicile in its adult stage, and Rhodniusprolixus, which is practically controlled in the country. Peridomestic vectors are of lower risk in the transmissiondynamics, as compared to the intradomestic ones. For the control of the intradomestic vectors, health educationprograms, improvements of housing, and the use of pesticides are essential To control the peridomestic vectors, healtheducation programs are required, as well as the use of mosquito nets on doors and windows and around beds, asidefrom cementing the stone wall fences.Los transmisores de Trypanosoma cruzi, flagelado causante de la enfermedad, se dividen en intradomiciliados,peridomiciliados y silvestres. Entre los intradomiciliados se encuentran, Triatoma barberi y Triatoma dimidiata, queson los que representan un mayor riesgo para la Salud Pública, en México. Aunque Triatoma dimidiata se encuentraprincipalmente dentro de la vivienda, en Yucatán tiene un comportamiento peridomiciliar, dentro de este grupo seencuentran la mayoría de los transmisores de la enfermedad de Chagas Meccus longipennis, M. mazzottii, M.pallidipennis, M. phyllosomus, M. picturatus, Triatoma gerstaeckeri, T. mexicana, T. rubida, Dipetalogaster máxima,Panstrongylus rufotuberculatus y Rhodnius prolixus. Los transmisores peridomiciliados son de menor riesgo en ladinámica de transmisión comparados con los intradomiciliados. Para el control de los transmisores intradomiciliados,se deben emplear programas de educación para la salud, mejoramiento de vivienda e insecticidas; mientras que paralos vectores visitantes o peridomiciliados, son necesarios programas de educación para la salud, uso de mosquiteros,pabellones y cementación de las bardas de piedra

    Lymphangioleiomyomatosis biomarkers linked to lung metastatic potential and cell stemness

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    Lymphangioleiomyomatosis (LAM) is a rare lung-metastasizing neoplasm caused by the proliferation of smooth muscle-like cells that commonly carry loss-of-function mutations in either the tuberous sclerosis complex 1 or 2 (TSC1 or TSC2) genes. While allosteric inhibition of the mechanistic target of rapamycin (mTOR) has shown substantial clinical benefit, complementary therapies are required to improve response and/or to treat specific patients. However, there is a lack of LAM biomarkers that could potentially be used to monitor the disease and to develop other targeted therapies. We hypothesized that the mediators of cancer metastasis to lung, particularly in breast cancer, also play a relevant role in LAM. Analyses across independent breast cancer datasets revealed associations between low TSC1/2 expression, altered mTOR complex 1 (mTORC1) pathway signaling, and metastasis to lung. Subsequently, immunohistochemical analyses of 23 LAM lesions revealed positivity in all cases for the lung metastasis mediators fascin 1 (FSCN1) and inhibitor of DNA binding 1 (ID1). Moreover, assessment of breast cancer stem or luminal progenitor cell biomarkers showed positivity in most LAM tissue for the aldehyde dehydrogenase 1 (ALDH1), integrin-ß3 (ITGB3/CD61), and/or the sex-determining region Y-box 9 (SOX9) proteins. The immunohistochemical analyses also provided evidence of heterogeneity between and within LAM cases. The analysis of Tsc2-deficient cells revealed relative over-expression of FSCN1 and ID1; however, Tsc2-deficient cells did not show higher sensitivity to ID1-based cancer inhibitors. Collectively, the results of this study reveal novel LAM biomarkers linked to breast cancer metastasis to lung and to cell stemness, which in turn might guide the assessment of additional or complementary therapeutic opportunities for LAM

    Transformar para educar 5: ambientes de aprendizaje naturalmente críticos

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    Este quinto libro de la colección "Transformar para Educar''.-producto de las investigaciones de aula adelantadas por docentes de la Universidad del Norte, con el apoyo del Centro para la Excelencia Docente (CEDU), en el marco del programa Transformación de curso-, busca difundir innovaciones en la práctica pedagógica, con el fin de mejorar las experiencias educativas de los estudiantes con base en la implementación de ambientes de aprendizaje naturalmente críticos. Son críticos porque los estudiantes razonan con sus propios argumentos y naturales porque se da de manera espontánea. Contiene nueve capítulos que recopilan las experiencias realizadas por los docentes del área de introducción a la Ingeniería. Confiamos en que los hallazgos que aquí se presentan sean de interés para los lectores y puedan ser compartidos de manera amplia entre distintos públicos

    Çédille, revista de estudios franceses

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    Presentació

    Blastocystis hominis y su relación con el estado nutricional de escolares en una comunidad de la sierra de Huayacocotla, Veracruz, México

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    Introduction. Blastocystis hominis is an emerging cosmopolitan protozoa intestinal parasite which causes diarrhoea in man. Aim. To determine the prevalence of Blastocystis hominis and its relationship with the nutritional state of a sample of schoolchildren in the Sierra de Huayacotla, Veracruz, Mexico. Materials and Methods. A coprological study of 100 schoolchildren between 6 and 14 from the Primary School in Teximalpa, Sierra de Huayacotla was carried out. Direct coproparasitoscopic analysis and the Faust method were used. Their nutritional state was analyzed using Body Mass Index (BMI) and the application of a questionnaire. The statistical analysis was carried out using X2 and Fishers� exact test. Results. The prevalence of B. hominis was 80%. It should be noted that its presence in children with a severe degree of thinness was significantly higher (p< 0.05). Moreover, the association between Blastocystis hominis and E. histolytica was (p<0.001). In children with acceptable thinness the association of B. hominis with E. nana showed (p<0.02), of B. hominis with E. coli (p <0.02) and of B. hominis with I. büestchlii showed (p<0.04). In children of normal weight the association of B. hominis and E. histolytica was p<0.009. Symptoms were vague and non-specific. Conclusions. It is clear that B. hominis affects BMI but its effect is synergic when associated with E. histolytica, E. nana, I. büestchlii and E. coli. The significant presence of protozoa transmitted by faeces is an indicator of the deficiencies in the health environment of the population. Thus, it is indispensable to pay greater attention to marginal communities in order to improve the development of their children.Introduccion. Blastocystis hominis es un protozoario intestinal cosmopolita emergente, causante de diarrea en los humanos. Objetivo. Conocer la prevalencia de B. hominis y su relacion con el estado nutricional de escolares en la Sierra de Huayacocotla, Veracruz, Mexico. Materiales y Metodos. Se realizo un estudio coprologico en 100 ninos de 6 a 14 anos, en la escuela primaria de Teximalpa, municipio de Huayacocotla. Consistio de un examen directo de heces y metodo de Faust, evaluacion nutricional mediante el indice de masa corporal (IMC), una encuesta y analisis estadistico con las pruebas de �Ô2 y exacta de Fisher. Resultados. La prevalencia de B. hominis fue de 80%. Es notable que la presencia de B. hominis en ninos con indice de delgadez severa resulto significativamente mayor (p <0.05) que en los ninos con otro IMC. Ademas, la asociacion de B. hominis y E. histolytica resulto significativa (p <0.001). Los ninos con IMC de delgadez aceptable y la asociacion simultanea de B. hominis y E. nana, o bien, de B. hominis y E. coli tuvieron el mismo nivel de significancia (p<0.02). La asociacion de B. hominis y I. buestchlii, en ninos con este mismo IMC, presento una p <0.04. En ninos con peso normal, la asociacion B. hominis y E. histolytica resulto p<0.009. Los sintomas fueron vagos e inespecificos. Conclusiones. Evidentemente B. hominis afecta el IMC. La afectacion es sinergica asociada con E. histolytica, E. nana, I buestchlii y E. coli. La alta presencia de protozoos transmitidos por fecalismo es un indicador del deficiente saneamiento ambiental de la poblacion. Es indispensable prestar mayor atencion a las comunidades marginadas, para mejorar el desarrollo de los ninos
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