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Grouping tree species to estimate basal area increment in temperate multispecies forests in Durango,Mexico

Forest Ecosystems 2024年第1期11卷 1-13页

作者： jaime Roberto Padilla-Martínez Carola Paul Kai Husmann Jose Javier Corral-Rivas Klaus von Gadow Department of Forest Economics and Sustainable Land-use Planning Faculty of Forest Sciences and Forest EcologyUniversity of GottingenBüsgenweg 137077GottingenGermany Facultad de Ciencias Forestales Universidad Juarez del Estado de DurangoRío Papaloapan y Boulevard Durango S/N34120DurangoMexico Faculty of Forestry and Forest Ecology Georg-August-UniversitatBüsgenweg 537077GottingenGermany Department of Forestry and Wood Science Faculty of AgriSciencesStellenbosch UniversityStellenbosch Private Bag X1Stellenbosch7602South Africa

Multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological ***,a greater species diversity presents challenges for forest management and *** study aims to develop basal area growth models for tree species *** analysis is based on a dataset of 423 permanent plots(2,500 m^(2))located in temperate forests in Durango,***,we define tree species cohorts based on individual and neighborhood-based variables using a combination of principal component and cluster ***,we estimate the basal area increment of each cohort through the generalized additive model to describe the effect of tree size,competition,stand density and site *** principal component and cluster analyses assign a total of 37 tree species to eight cohorts that differed primarily with regard to the distribution of tree size and vertical position within the *** generalized additive models provide satisfactory estimates of tree growth for the species cohorts,explaining between 19 and 53 percent of the total variation of basal area increment,and highlight the following results:i)most cohorts show a"rise-and-fall"effect of tree size on tree growth;ii)surprisingly,the competition index"basal area of larger trees"had showed a positive effect in four of the eight cohorts;iii)stand density had a negative effect on basal area increment,though the effect was minor in medium-and high-density stands,and iv)basal area growth was positively correlated with site quality except for an oak *** developed species cohorts and growth models provide insight into their particular ecological features and growth patterns that may support the development of sustainable management strategies for temperate multispecies forests.

关键词： Temperate multispecies forests Cluster analysis Basal area increment Generalized additive models

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Dichloro-Diphenyl-Trichloroethane (DDT) and Endosulfan in Sediments of Sabancuy Lagoon, Campeche, Mexico

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Open Journal of Ecology 2016年第1期6卷 22-31页

作者： Miguel Angel Ramírez-Elías Atl Victor Córdova-Quiroz Julia Griselda Cerón-Bretón Rosa María Cerón-Bretón jaime rendón-von osten Javier Hipólito Cortés-Simón Facultad de Química Universidad Autónoma del Carmen Ciudad del Carmen México Centro de Ecología Pesquerías y Oceanografía del Golfo de México (EPOMEX) Universidad Autónoma de Campeche Campeche México Secretaria de Marina V Zona Naval Estación de Investigación Oceanográfica Cd del Carmen Campeche México

DDT and Endosulfan are persistent organic compounds which have been prohibited and their use has been limited in agricultural activities due to their toxicity, persistence and bioaccumulation potential. The use of DDT in fumigation campaigns against endemic diseases transmitted by vectors of malaria and dengue was prohibited in Carmen Island, Campeche, Mexico since 1995. In the surroundings of Sabancuy Lagoon, many and diverse agricultural activities are carried out and it is a common practice to use organ-chlorine pesticides as endosulfan. In order to know the levels of these compounds in this area, a sediment sampling campaign was carried out in ten sampling points randomly located within the Sabancuy Lagoon, Campeche and considering one reference sampling point located 2 km away from Sabancuy Lagoon within the Mexican Gulf. Three metabolites were identified in sediments samples belonging to DDT’s family: (4,4’-DDD;4,4’-DDE;4,4’- DDT) and Endosulfan’s family (Endosulfan I, Endosulfan II y Endosulfan sulfate). Higher concentrations in DDT’s family were found for 4,4’-DDD, followed by 4,4’-DDE and 4,4’-DDT. Endosulfan’s family, showed the following order for concentrations: Endosulfan II > Endosulfan I > Endosulfan sulfate. Mean concentration for S-DDT and S-Endosulfan in Sabancuy Lagoon sediments was twice higher than those found in other studies carried out in Términos Lagoon, Campeche, Mexico in 2002.

关键词： Organochlorine Pesticides Pollution Sabancuy Coastal Lagoons

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Microstructural Characterization of Large Area C<sub>60</sub>Films Obtained by Conventional Microwave Oven Irradiation

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World Journal of nano Science and Engineering 2012年第4期2卷 213-218页

作者： Jacobo Martínez-Reyes Lucia Graciela Díaz Barriga-Arceo Luis rendón-Vazquez Reynaldo Martínez-Guerrero néstor Romero-Partida Eduardo Palacios-González Vicente Garibay-Febles jaime Ortiz-López IMP-Molecular Engineering Program México City México national Polytechnic Institute (IPn) ESFM UPALM México City México national Polytechnic Institute (IPn) ESIQIE UPALM México City México ROMFER S.A. de C.V. México City México UnAM-FCiencias México City México

In the present work the synthesis of C60 produced in a conventional microwave oven from the decomposition of camphor resin is reported. The polycrystalline structure of the sample was determined by X-Ray Diffraction (XRD), the sample showed several phases, the main phase corresponds to fullerene C60 ordered in a Face-Centered Cubic structure (FCC), with two more structures: one orthorhombic system and the other the monoclinic system coexisting also with graphite 2H phase. It was observed in a Scanning Electron Microscopy (SEM), that the sample formed thin films of stacked carbon. Whereas in a High Resolution Transmission Electron Microscopy (HRTEM), measurements in Bright Field mode revealed that the main phase of the material is C60 ordered in FCC structure and the elemental composition and atomic bonding state can be determined by analyzing the energy with the electron microscope by Elesctron Energy- Loss Spectroscopy (EELS), technique allowed confirm all the phase C60 established with XRD observations.

关键词： Microwave-Assisted Synthesis Carbon Film Fullerene

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Final Diagnosis of Pediatric Patients with Prolonged in Activated Partial Thromboplastin Time Preoperative Study

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International Journal of Otolaryngology and Head & neck Surgery 2015年第3期4卷 241-247页

作者： noemi Aguirre Francisca Cordova Francisca jaime Ximena Fonseca Pamela Zúniga Pediatrics Resident Pontifical Catholic University of ChileSantiagoChile School of Medicine Pontifical Catholic University of ChileSantiagoChile Pediatrician Resident of Pediatric Gastroenterology and NutritionPontifical Catholic University of ChileSantiagoChile Otorhinolaryngologist Assistant ProfessorPediatrics DivisionMedical SchoolPontifical Catholic University of ChileSantiagoChile Hematologist-Oncologist Assistant ProfessorPediatrics DivisionMedical SchoolPontifical Catholic University of ChileSantiagoChile

Introduction: Activated partial thromboplastin time (aPTT) is one of the most used coagulation tests in preoperative evaluation. Incidental detection of a prolonged aPTT is a problem in primary care, in which the general pediatrician should be able to attend its initial management. Objective: To describe final diagnosis of patients with prolonged aPTT in preoperative study. Materials and Methods: This is a descriptive study of patients referred from otorhinolaryngology. Results: Totally, 508 adenoidectomies and/or tonsillectomies were performed in our center, 38 of which referred patients (7.5%) with prolonged aPTT, and 30 of which met inclusion criteria. The median age was 4 years. 56.6% of patients were males. 76.6% of patients normalized aPTT at the second follow-up. Among these, 73.9% showed a normal study, 4.3% ha2d lupus anticoagulant and in 21.7% von Willebrand disease was detected. Among patients that persisted with prolonged aPTT, 42.8% had coagulant factors deficiency, 28.5% had lupus anticoagulant and in 28.5% of patients a diagnosis could not be achieved with the tests used in the present study. Multivariate analysis did not show correlation between final diagnosis and the variables measured. Conclusion: The presence of a prolonged aPTT in children under preoperative study is due to a pre-analytic factor in the majority of cases or to the presence of lupus anticoagulant, normalizing values on follow-up. We suggest that a new aPTT be performed on these patients, and only those that persist altered or present a symptoms and family history of coagulation disorders be referred to hematology.

关键词： aPTT Preoperative Study Tonsillectomy Adenoidectomy Coagulopathy

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