Modeling population dynamics of invasive pines to optimize their control in native grasslands of Argentina.

The spread of invasive alien species over natural environments has become one of the most serious threats to biodiversity and the functioning of ecosystems worldwide. Understanding the population attributes that allow a given species to become invasive is crucial for improving prevention and control interventions. Pampas grasslands are particularly sensitive to the invasion of exotic woody plants. In particular, the Ventania Mountains undergo the advance of alien woody plants; among which the Aleppo pine (Pinus halepensis) stands out due to the extension of the area it covers and the magnitude of the ecological changes associated to its presence. Using a model that describes the population dynamics of the species in the area, we evaluated the expected behavior of the population under different environmental conditions and different management scenarios. When the effect of stochastic fires was simulated, the growth rate was greater than 1 for all the frequencies considered, peaking under fires every nine years, on average. When evaluating the effect of periodic mechanical control of the adult population, the reduction in growth rate was insufficient, except for cutting intensities that significantly exceeded the current operational capacity of the area. Under prescribed fire scenarios, on the other hand, burning frequencies greater than seven years resulted in population reductions. The results highlight the importance of fire in regulating the population of P. halepensis in the Ventania Mountains, with contrasting effects depending on the frequency with which it occurs, which allows considering it as an effective environmental management option for the control of the species.

Evolución de la osteosíntesis de los huesos largos y fijación por enclavado intramedular flexible / Evolution of Long Bone Osteosynthesis and Flexible Intramedullary Nail Fixation

Introducción: Se presenta la evolución histórica y científica de la osteosíntesis de huesos largos realizada con dos tipos de implantes intramedulares: Pines o varillas flexibles y clavos rígidos. Objetivo: Publicar un artículo científico que sirva de soporte teórico y práctico al personal en formación y, como punto de referencia y consulta a los ortopédicos y traumatólogos. Métodos: Se realiza una revisión bibliográfica retrospectiva de artículos sobre fracturas de los miembros publicadas en revistas de traumatología nacionales y extranjeras indexadas en las bases de datos MEDLINE y certificadas por el organismo de Ciencia Tecnología y Medio Ambiente, así como libros de relevancia sobre este tema y experiencias de los autores. Dadas las diferencias entre los dos tipos de implantes se estudiaron por separado la osteosíntesis con pines flexibles (Rush) y la realizada con clavos rígidos (Küntscher). Se seleccionaron las siguientes variables para el estudio: reducción, vía de acceso, penetración del implante, estabilidad, bloqueo, metal usado y consolidación. La fecha de incorporación de las innovaciones tecnológicas a la práctica quirúrgica fue enmarcada en tres momentos generacionales en el período de tiempo comprendido desde 1939 hasta la actualidad. Conclusiones: Esta revisión permitió identificar dos tipos de implantes intramedulares: los pines flexibles y los clavos rígidos. El estudio de sus características permitió organizarlos en generaciones para poder ubicar en el tiempo su contribución a los conocimientos que permiten devolver al paciente su vida activa(AU)

Introduction: This article discuses the historical and scientific evolution of long bone osteosynthesis performed with two types of intramedullary implants, flexible pins or rods and rigid nails. Objective: To publish a scientific article that serves as theoretical and practical support for staff in training and, as a point of reference and consultation for orthopedists and traumatologists. Methods: A retrospective bibliographic review of articles is carried out on limb fractures published in local and foreign trauma journals indexed in the MEDLINE databases and certified by CITMA, as well as relevant books on this topic and experiences of the authors. Given the differences between the two types of implants, we separately studied the osteosynthesis with flexible pins (Rush) from that performed with rigid pins (Küntscher). The variables selected for the study were reduction, access route, implant penetration, stability, locking, metal used, and consolidation. The inclusion of technological innovations to surgical practice was framed in three generational moments from 1939 to the present. Conclusions: Thow types of intramedullary implants were identifies from this revision: flexible pins and rigid nails. The study of their characteristics allowed to organize them into generations in order to locate their contribution to the knowledge allowing the patient to return to an active life over time(AU)

Coalescent-based species delimitation in North American pinyon pines using low-copy nuclear genes and plastomes.

PREMISE: Accurate species delimitation is essential for evolutionary biology, conservation, and biodiversity management. We studied species delimitation in North American pinyon pines, Pinus subsection Cembroides, a natural group with high levels of incomplete lineage sorting. METHODS: We used coalescent-based methods and multivariate analyses of low-copy number nuclear genes and nearly complete high-copy number plastomes generated with the Hyb-Seq method. The three coalescent-based species delimitation methods evaluated were the Generalized Mixed Yule Coalescent (GMYC), Poisson Tree Process (PTP), and Trinomial Distribution of Triplets (Tr2). We also measured admixture in populations with possible introgression. RESULTS: Our results show inconsistencies among GMYC, PTP, and Tr2. The single-locus based GMYC analysis of plastid DNA recovered a higher number of species (up to 24 entities, including singleton lineages and clusters) than PTP and the multi-locus coalescent approach. The PTP analysis identified 10 species whereas Tr2 recovered 13, which agreed closely with taxonomic treatments. CONCLUSIONS: We found that PTP and GMYC identified species with low levels of ILS and high morphological divergence (P. maximartinezii, P. pinceana, and P. rzedowskii). However, GMYC method oversplit species by identification of more divergent samples as singletons. Moreover, both PTP and GMYC were incapable of identifying some species that are readily identified morphologically. We suggest that the divergence times between lineages within North American pinyon pines are so disparate that GMYC results are unreliable. Results of the Tr2 method coincided well with previous delimitations based on morphology, DNA, geography, and secondary chemistry.

Síndrome de fricción de la cintilla iliotibial posterior a reconstrucción del ligamento cruzado anterior con pines transversos bioabsorbibles / Iliotibial band friction syndrome due to bioabsorbable pins in ACL reconstruction

Resumen: Las lesiones del ligamento cruzado anterior (LCA) hoy en día son tratadas principalmente con injerto de isquiotibiales y una amplia gama de técnicas y sistemas de fijación del LCA en busca de una menor morbilidad del paciente. Se reporta un caso de una paciente de 42 años que sufrió ruptura de LCA, tratada con reconstrucción de LCA con injerto autólogo de isquiotibiales, fijación femoral con pines transversos bioabsorbibles y fijación tibial con tornillo bioabsorbible. La paciente evolucionó con presencia de dolor en región lateral de rodilla, diagnosticado como síndrome de fricción de la banda iliotibial un año posterior a la cirugía. Se realizaron estudios de imagen que incluyeron rayos X y resonancia magnética (RM) donde se observó adecuada fijación del LCA con presencia de migración y ruptura del pin proximal bioabsorbible. Se decidió extraer el fragmento del pin bioabsrobile en un segundo tiempo quirúrgico y la paciente regresó a sus actividades cotidianas y deportivas sin dolor y con una adecuada estabilidad.

Abstract: Injuries of the anterior cruciate ligament are currently treated primarily with the use of hamstring graft with a wide range of different techniques and fixation systems for anterior cruciate ligament in reducing patient morbidity. We report the case of a female patient aged 42 that suffered an anterior cruciate ligament rupture and was treated with anterior cruciate ligament reconstruction with hamstring autograft with femoral fixation with bio-absorbable cross-pin and tibial fixation with bio-absorbable screw. The patient presented lateral knee pain that was diagnosed one year after the operation as an iliotibial band friction syndrome. Imaging studies were performed. X-rays and magnetic resonance imaging demonstrated adequate fixation of the anterior cruciate ligament with the presence of migration and rupture of the proximal bio-absorbable cross-pin. It was decided to remove the bio-absorbable cross-pin fragment in a second surgical procedure after which the patient went back to her daily activities and sports without pain and with stability stable knee.

A Modified Protocol for High-Quality RNA Extraction from Oleoresin-Producing Adult Pines.

RNA extraction resulting in good yields and quality is a fundamental step for the analyses of transcriptomes through high-throughput sequencing technologies, microarray, and also northern blots, RT-PCR, and RTqPCR. Even though many specific protocols designed for plants with high content of secondary metabolites have been developed, these are often expensive, time consuming, and not suitable for a wide range of tissues. Here we present a modification of the method previously described using the commercially available Concert™ Plant RNA Reagent (Invitrogen) buffer for field-grown adult pine trees with high oleoresin content.