Estrategias didácticas para potenciar el pensamiento matemático a partir de situaciones del entorno métrico-Teaching strategies to enhance mathematical thinking from environmental situations metric

En el presente artículo se comparten los frutos de una investigación sobre algunas estrategias tendientes a potenciar el pensamiento métrico en estudiantes de noveno grado de Educación Básica, a través de situaciones problema del contexto sociocultural y de las ciencias, bajo un diseño cualitativo. Se realizó un análisis didáctico, en relación con la comprensión de los conceptos, procedimientos y aplicaciones del pensamiento métrico, de los abordajes y soluciones de los estudiantes a las 15 situaciones de la prueba diagnóstica y de la prueba de contraste, diseñadas para reconocimiento de posibles dificultades de los estudiantes y para valorar el logro de las estrategias aplicadas, y algunas de la intervención en el aula usadas para superación de las dificultades detectadas

Síndrome de Noonan: actualización genética, clínica y de opciones terapéuticas

El síndrome de Noonan (SN) es una enfermedad de origen genético relativamente frecuente cuyas manifestaciones fundamentales son la talla baja, la cardiopatía congénita y un fenotipo facial característico. La causa del síndrome de Noonan y de otras enfermedades clínicamente solapadas como el síndrome de Noonan con lentiginosis múltiple (anteriormente llamado síndrome LEOPARD), el cardiofaciocutáneo o el síndrome de Costello, son mutaciones en genes que codifican para proteínas de la vía de señalización de las RAS-MAPKinasas. Debido a este sustrato común este grupo de enfermedades son denominadas colectivamente «rasopatías». A pesar de los avances genéticos de las últimas décadas, cerca de 20% de pacientes no tienen causa genética identificada, y el diagnóstico sigue siendo clínico. El síndrome de Noonan se caracteriza por una alta heterogeneidad clínica y genética, con afectación variable, y cambiante con la edad, de múltiples órganos y sistemas. Debido a esta variabilidad es fundamental que los médicos involucrados en su cuidado estén familiarizados con sus manifestaciones y conozcan las recomendaciones de seguimiento, incluido el seguimiento del crecimiento y desarrollo. Hasta la fecha los escasos datos de crecimiento con GH a talla adulta dan resultados de ganancia de talla moderados, semejantes a los obtenidos en el síndrome de Turner. La hiperactivación de la vía RAS-MAPK como base común de esta familia de enfermedades brinda una oportunidad única para el desarrollo de tratamientos dirigidos a la etiología de estos trastornos. Noonan syndrome (NS) is a relatively common genetic condition characterised by short stature, congenital heart defects, and distinctive facial features. NS and other clinically overlapping conditions such as NS with multiple lentigines (formerly called LEOPARD syndrome), cardiofaciocutaneous syndrome, or Costello syndrome, are caused by mutations in genes encoding proteins of the RAS-MAPKinases pathway. Because of this shared mechanism, these conditions have been collectively termed «RASopathies». Despite the recent advances in molecular genetics, nearly 20% of patients still lack a genetic cause, and diagnosis is still made mainly on clinical grounds. NS is a clinically and genetically heterogeneous condition, with variable expressivity and a changing phenotype with age, and affects multiple organs and systems. Therefore, it is essential that physicians involved in the care of these patients are familiarised with their manifestations and the management recommendations, including management of growth and development. Data on growth hormone treatment efficacy are sparse, and show a modest response in height gains, similar to that observed in Turner syndrome. The role of RAS/MAPK hyper-activation in the pathophysiology of this group of disorders offers a unique opportunity for the development of targeted approaches

Introgressive hybridization in a Spiny-Tailed Iguana, Ctenosaura pectinata, and its implications for taxonomy and conservation

Introgression, the transmission of genetic material of one taxon into another through hybridization, can have various evolutionary outcomes. Previous studies have detected signs of introgression between western populations of the Mexican endemic and threatened spiny-tailed iguana, Ctenosaura pectinata. However, the extent of this phenomenon along the geographic distribution of the species is unknown. Here, we use multilocus data together with detailed geographic sampling to (1) define genotypic clusters within C. pectinata; (2) evaluate geographic concordance between maternally and biparentally inherited markers; (3) examine levels of introgression between genotypic clusters, and (4) suggest taxonomic modifications in light of this information. Applying clustering methods to genotypes of 341 individuals from 49 localities of C. pectinata and the closely related C. acanthura, we inferred the existence of five genotypic clusters. Contact zones between genotypic clusters with signatures of interbreeding were detected, showing different levels of geographic discordance with mtDNA lineages. In northern localities, mtDNA and microsatellites exhibit concordant distributions, supporting the resurrection of C. brachylopha. Similar concordance is observed along the distribution of C. acanthura, confirming its unique taxonomic identity. Genetic and geographic concordance is also observed for populations within southwestern Mexico, where the recognition of a new species awaits in depth taxonomic revision. In contrast, in western localities a striking pattern of discordance was detected where up to six mtDNA lineages co-occur with only two genotypic clusters. Given that the type specimen originated from this area, we suggest that individuals from western Mexico keep the name C. pectinata. Our results have profound implications for conservation, management, and forensics of Mexican iguanas

Data from: Domestication genomics of the open-pollinated scarlet runner bean (Phaseolus coccineus L.)

The runner bean is a legume species from Mesoamerica closely related to common bean (Phaseolus vulgaris). It is a perennial species, but it is usually cultivated in small-scale agriculture as an annual crop for its dry seeds and edible immature pods. Unlike the common bean, P. coccineus has received little attention from a genetic standpoint. In this work we aim to (1) provide information about the domestication history and domestication events of P. coccineus; (2) examine the distribution and level of genetic diversity in wild and cultivated Mexican populations of this species; and, (3) identify candidate loci to natural and artificial selection. For this, we generated genotyping by sequencing data (42,548 SNPs) from 242 individuals of P. coccineus and the domesticated forms of the closely related species P. vulgaris (20) and P. dumosus (35). Eight genetic clusters were detected, of which half corresponds to wild populations and the rest to domesticated plants. The cultivated populations conform a monophyletic clade, suggesting that only one domestication event occurred in Mexico, and that it took place around populations of the Trans-Mexican Volcanic Belt. No difference between wild and domesticated levels of genetic diversity was detected and effective population sizes are relatively high, supporting a weak genetic bottleneck during domestication. Most populations presented an excess of heterozygotes, probably due to inbreeding depression. One population of P. coccineus subsp. striatus had the greatest excess and seems to be genetically isolated despite being geographically close to other wild populations. Contrasting with previous studies, we did not find evidence of recent gene flow between wild and cultivated populations. Based on outlier detection methods, we identified 24 domestication-related SNPs, 13 related to cultivar diversification and eight under natural selection. Few of these SNPs fell within annotated loci, but the annotated domestication-related SNPs are highly expressed in flowers and pods. Our results contribute to the understanding of the domestication history of P. coccineus, and highlight how the genetic signatures of domestication can be substantially different between closely related species

Scripts and data of Phaseolus coccineus population genomics

Script for genomic population analyses of wild and cultivated populations of Scarlet Runner Bean (Phaseolus coccineus). Please consult README file for detail information

Estrategias didácticas para potenciar el pensamiento matemático a partir de situaciones del entorno métrico-Teaching strategies to enhance mathematical thinking from environmental situations metric

En el presente artículo se comparten los frutos de una investigación sobre algunas estrategias tendientes a potenciar el pensamiento métrico en estudiantes de noveno grado de Educación Básica, a través de situaciones problema del contexto sociocultural y de las ciencias, bajo un diseño cualitativo. Se realizó un análisis didáctico, en relación con la comprensión de los conceptos, procedimientos y aplicaciones del pensamiento métrico, de los abordajes y soluciones de los estudiantes a las 15 situaciones de la prueba diagnóstica y de la prueba de contraste, diseñadas para reconocimiento de posibles dificultades de los estudiantes y para valorar el logro de las estrategias aplicadas, y algunas de la intervención en el aula usadas para superación de las dificultades detectadas

microsatellite genotypes table

Genotypes for 374 crocodile individuals obtained in the study based on 12 polymorphic microsatellites loc

Data from: Ancestral hybridization yields evolutionary distinct hybrids lineages and species boundaries in crocodiles, posing unique conservation conundrums

Interspecific hybridization can lead to adaptation and speciation, especially in the context of recent radiations. The emblematic Crocodylus (true crocodiles) is the most broadly distributed, ecologically diverse, and species-rich crocodylian genus. Nonetheless, their within-species evolutionary processes are poorly resolved mainly due to their potential for hybridization. Notably, the evolutionary outcomes when hybridization is ancient and involves long-lived species, like crocodiles, remain largely unexplored. Here, we evaluate the genomic admixture between the American (Crocodylus acutus) and the Morelet’s (Crocodylus moreletii) species, and demonstrate that this hybridization system challenges the definition of species boundaries and poses a triple conservation conundrum: what has been recognized as C. acutus is actually two distinct species, therefore its taxonomic reassessment is needed; we identified two evolutionary distinct hybrids lineages, which are genetically discernible from the parental species; the remaining C. moreletii populations evidence its likely extinction as a species and/or evolution via hybridization. Hence, the crocodiles’ distinct species and hybrids lineages warrant recognition and need urgent conservation efforts

SNPs data

Acutus_moreletii_SNPs.vcf - This file includes 12879 SNP markers identified in Crocodylus acutus and C. moreletii from Mexico