Search

El estudio muestra el alcance de un taller para fomentar la competencia de reflexión docente desde las nociones teóricas del modelo MTSK. Considera las manifestaciones de un grupo de docentes de matemáticas en servicio cuando analizan una situación de enseñanza-aprendizaje sobre el concepto matemático de relación desde su experiencia en la Educación Secundaria costarricense, tanto previas a la intervención, como posteriores al proceso de capacitación. Los resultados muestran un progreso en el desarrollo de esta competencia. No obstante, se evidenciaron dificultades para identificar aspectos relevantes de la situación analizada, como proposiciones que definen un concepto, formas de proceder en la matemática y elementos de una tarea matemática escolar.

Dinosaur trackway studies provide valuable insights into extinct animals' locomotor behaviour. Despite limitations arising from the inability to directly observe these trackmakers, speed and gait estimation formulae have become standard tools in the field of dinosaur ichnology. Stride length has traditionally been used to estimate dinosaur average speed and intra-trackway speed variations, but its unilateral focus can overlook some nuances within trackways. Alternatively, the contralateral measure pace length may not always align with the direction of travel. Analysing data from the Mancheon-ri tracksite and others, our results show that step length aligns advantageously along the trackway axis and captures nuanced speed variations. Incorporating additional parameters such as cadence and step duration enriches our understanding of the trackmaker's movements. Cadence summarises the overall rhythm of movement across trackways, and step duration reveals temporal variations between individual steps, offering potential for 3D animated reconstructions of dinosaur behaviour. Despite these methodologies' inherent limitations and assumptions, they provided a more refined understanding of dinosaur locomotion and behavioural patterns. Acknowledging the limitations of studying unobservable trackmakers, our estimations – based on established formulas for hip height and speed – are both rooted in accepted methodologies and remain informative, enhancing our understanding of dinosaur trackmaker behaviours. [ABSTRACT FROM AUTHOR]

This study introduces new discoveries of fossil footprints from the Middle Jurassic Yaopo Formation in Beijing, China, marking the first reptile fossils that have been discovered in this formation. The two small footprints with parallel digits and drag marks suggest they were made by tetrapods moving through water. While there are similarities to crocodylian and pterosaur tracks, the evaluation suggests that turtles are the most likely trace-makers. If correct, the Yaopo Formation footprints are likely made by xinjiangchelyids, given their dominance in Asian freshwater ecosystems during the Late Jurassic and their widespread distribution in Late Jurassic China. Sichuanchelyids, Bashuchelyidae, and Hongkongochelys are less likely candidates due to their limited temporal and geographical distribution. This finding adds to the growing body of evidence on the evolution and ecology of turtles in Asia during the Late Jurassic period. These new findings offer important insights into the behaviour and spatiotemporal occurrence of these ancient reptiles and expand our understanding of their role in prehistoric aquatic ecosystems. [ABSTRACT FROM AUTHOR]

This study is part of the research in didactics of mathematics on teacher training. In particular, the study focuses on the knowledge of mathematics teachers, taking as a reference the theoretical approaches of the Mathematics Teacher’s Specialized Knowledge (MTSK) model and teacher reflection as a professional competence. The study corresponds to a descriptive-qualitative research, based on an instrumental study of cases, whose purpose is to describe and analyze the manifestations of mathematics teachers of Secondary Education when they observe a teaching-learning situation that shows a teacher of mathematics teaching the concept of relation. For this, narratives written by seven Secondary Education mathematics teachers in service were used, which indicate some aspects identified by them as relevant from the observed situation. The analysis of the gathered information was carried out by defining categories, subcategories, and analysis units based on the components of the MTSK model. The results indicate that participating teachers accentuate, in their manifestations, attributes mainly associated with didactic knowledge of mathematical content. The reflection of this group of teachers is characterized by three specific aspects of the MTSK model: teaching, learning, and knowledge of the topics. It is interpreted that teacher reflection has been influenced by the professional experience of the teachers participating in the study.

This study offers a review of the antecedents, dimensions, and challenges of citizen participation in risk management in the city of Asuncion in Paraguay and its surrounding municipalities. The applied methodology consisted of a systematized bibliographic review developed in four phases: search, evaluation, analysis, and synthesis. The analyzed data were grouped into four dimensions: historical, socio-demographic, environmental, and political. The obtained results highlight ‘citizenparticipation’ as a priority in documents referring to international and national public policies on risk management. In the selected case of study, however, this participation is mainly limited to only ‘formal’ aspects rather than observed in practice. The latter has left little power to citizens for the incidence and control of risk management at a national and local levels.

Elongate tracks with metatarsal marks are a rare type of dinosaur track that have been identified in various locations around the world. These tracks have been attributed to both theropods and ornithischians, and the mechanism of their formation has remained elusive. In this study, we describe well-preserved elongate tracks with metatarsal marks from two adjacent track sites in the Lower Jurassic Fengjiahe Formation in Yunnan Province, China. These tracks occur together with 'normal' tridactyl tracks that lack a metatarsal mark. The tracks were produced by theropod dinosaurs and are consistent with the classic Lower Jurassic Eubrontes-Grallator-Kayentapus assemblage found in the United States. We propose that these elongate tracks are formed by deep penetrations of the foot in soft substrate, where sediment collapses above parts of the descending foot, leaving a shallow surface track that preserves a metatarsal mark. Our findings provide new insights into the locomotion and behaviour of Early Jurassic theropod dinosaurs and highlight the importance of Yunnan Province in the study of dinosaur tracks in China. [ABSTRACT FROM AUTHOR]

We report five new dinosaur track sites in Chaya County, about 120 km southeast of Changdu City. The track assemblages are dominated by sauropods (45 tracks), which have been identified tentatively as cf. Brontopodus. Also present are two thyreophoran trackways consisting of 13 tracks that show strong similarities with the ichnogenus Deltapodus, the potential trackmakers of which were probably stegosaurids. The sauropod tracks from the Chaya region are dominated by large tracks with different affinities if compared to those of the Changdu area. The isolated sauropod tracks from Changdu and Chaya regions show similar morphological patterns, but those from the Chaya region lack large scale tracks. This paper compares and discusses the known ichno and body fossil records of sauropods, theropods, and ornithischians from the Middle Jurassic of Yunnan, Sichuan, and eastern Tibet and their importance for our understanding of dinosaur faunas from this region. The absence of basal neornithischian records in the Yunnan and Changdu regions is likely a preservational bias but also an ecological pecularity cannot be completely excluded. The palaeogeographic position of the four sampled skeleton and track sites suggests the possible existence of a corridor through which faunal exchanges were taking place throughout the Jurassic. [ABSTRACT FROM AUTHOR]

Recently, dinosaur tracks were discovered in the vicinity of Zhemujiu village in Yimen County, Yunnan Province, representing the first dinosaur footprints found in the purplish-red sandy mudstone of Lower Jurassic Zhanghe Formation. This marks a significant discovery as evidence of dinosaurs from this formation has previously only been reported from body fossils. Nearly 100 tracks were observed at the site and two morphotypes were identified: Characichnos-like morphotype A, and Wintonopus-like morphotype B. Some dinosaurs scraped the substrate with the distal portions of their digits (morphotype A), while others punted by pushing either the digital plantar surface against the sediment or plunging their digits vertically into the sediment (morphotype B). These track morphotypes suggest small-bodied dinosaurs swam (fully buoyant) and punted (partially buoyant) aqueous palaeo-environments (respectively). The orientation of these Zhemujiu tracks indicates that some dinosaurs were moving along the same axis as the flow of the water while others were moving perpendicular to it, yet despite the high abundance and shared orientations of tracks, we find no evidence of gregarious behaviour. This Zhemujiu tracksite discovery expands our understanding of dinosaur swimming behaviour in the Mesozoic era, as well as the occurrence of these track morphologies in China. [ABSTRACT FROM AUTHOR]

A possible turtle swim track from the Third Member of the Late Triassic Xujiahe Formation (Norian-Rhaetian) represents the oldest ichnological evidence of the group from China, supplementing previous reports of more abundant tracks from the Middle Jurassic of the region. The specimen is younger than the known pantestudinate ('stem-turtle') body fossils from China but matches the stratigraphic distribution of testudinate skeletons in other regions, for example, in Thailand, Europe and North America. Caution should be used to distinguish turtle swim tracks from those of crocodylomorphs and theropod dinosaurs, especially where only small samples are available. Therefore, we do not completely exclude an affinity with these groups or other archosaurs, such as phytosaurs. Nevertheless, the morphology of the imprints is most similar to turtle tracks, and it is most likely that an early non-crown group representative was the responsible producer. Of interest is also the depositional environment of the track-bearing deposit, which can be considered a deltaic plain marsh. [ABSTRACT FROM AUTHOR]

El cuidado, es una necesidad y un derecho durante todas las etapas del desarrollo del ser humano, es realizado mayoritariamente por las mujeres, pero es desvalorizado social y económicamente en sociedades patriarcales, perjudicando el ejercicio de sus derechos y su ciudadanía social. Desde el concepto de la organización social del cuidado, esta investigación tiene por objetivo, analizar la incidencia de factores socioculturales en el imaginario y en las prácticas de las mujeres en relación a su rol de cuidado de niñas y niños con discapacidad física que, en el año 2015, asistieron al Programa Educativo para Niños con Discapacidad Física en Asunción. Es de tipo exploratorio, de carácter cualitativo y con muestreo por conveniencia. Se utilizan entrevistas en profundidad con una guía de preguntas. Se utilizó una matriz de categorías y la técnica del análisis de discursos para el análisis. Los resultados obtenidos muestran que, los imaginarios y las prácticas sociales de las mujeres entrevistadas, están influenciadas por representaciones sociales basadas en la división sexual del trabajo con las que explican, justifican y refuerzan el reparto tradicional de los roles de cuidados, lo que implicó para ellas, el aumento de su tiempo total de trabajo en perjuicio de su bienestar. Para sobrellevarlo, sus estrategias de resistencias son de carácter personal, y desarticuladas de servicios públicos u organizativos. En conclusión, estas mujeres, por influencia de la división sexual del trabajo asocian la maternidad y los cuidados como sus funciones naturales e ineludibles, asumiendo la sobrecarga de los cuidados, privilegiando a los hombres y la acumulación. Si esto no se revierte, se seguirá perjudicando el bienestar principalmente de las mujeres.

Analizamos el conocimiento de profesores de matemáticas de Educación Secundaria sobre la realización de procesos matemáticos en el aula para apoyar el desarrollo de la competencia matemática de los estudiantes. Para ello, identificamos y describimos los cambios en los conocimientos, capacidades y actitudes del profesorado, relacionados con el uso de procesos matemáticos en el diseño de tareas, a partir de su participación en una propuesta formativa con base en la reforma curricular en matemáticas en Costa Rica. Observamos que los profesores desarrollaron capacidades para vincular habilidades, procesos y competencias, justificar esta vinculación y, diseñar y seleccionar tareas que la atendieran.

Abstract A new Middle Jurassic tracksite dominated by non-avian theropod footprints from the Wangjiashan Formation in Pingchuan District, Baojishan Basin, Gansu Province has yielded a unique trackway with four consecutive manus-pes sets. Only three previous examples, all Early Jurassic in age, of theropod trackways are known with convincing examples of manus tracks and in each case, only two tracks were recorded in association with pes tracks with metatarsal impressions and pelvic traces indicating crouching behavior. Thus, this is the first example of manus tracks registered while a theropod trackmaker was walking. This unique configuration is here designated as Grallator pingchuanensis ichnosp. nov. which shows the trackmaker forelimbs registering in a wide straddle gait, much wider than the pes trackway width. G. pingchuanensis confirms previous reports that theropods could occasionally register tridactyl, ectaxonic manus traces. In the case of the Pingchuan trackway, the short step indicates an animal moving at a slow speed, probably due to a soft substrate.

Rich tetrapod ichnofaunas, known for more than a decade, from the Huangyangquan Reservoir (Wuerhe District, Karamay City, Xinjiang) have been an abundant source of some of the largest Lower Cretaceous track collections from China. They originate from inland lacustrine clastic exposures of the 581–877 m thick Tugulu Group, variously divided into four formations and subgroups in the northwestern margin of the Junggar Basin. The large Huangyangquan track assemblages occur in the Lower layer/Subgroup II. Similarly-composed track assemblages also occur at the smaller Asphaltite site in the Upper Layer/Subgroup III. The Huangyangquan assemblages have yielded more than 1,500 identified tracks including abundant tracks of avian and non-avian theropods, pterosaurs and turtles and less abundant tracks of stegosaurs. Previous avian track identifications have been reassessed to conclude that Moguiornipes robustus is a taphotaxon and Koreanaornis dodsoni might be better accommodated in the ichnogenus Aquatilavipes which appears to be the dominant avian ichnotaxon. The avian track Ignotornis is also recognized and represents the first occurrence of this ichnogenus in China. Although the Huangyangquan assemblages lack some of the larger components (e.g., sauropodan and ornithopodan tracks) known from other Lower Cretaceous localities, the association of abundant tracks of smaller tetrapods (avian and non-avian theropods, pterosaurs and turtles) appears to be representative of lacustrine basin faunas of this region, and are an excellent example of the shorebird ichnocoenosis/ichnofacies concept. This is the first comprehensive review and re-analysis of an important Lower Cretaceous ecosystem.

Abstract A relatively small number of tetrapod tracksites from Zhejiang Province fills out the fossil record from that region, which is also known to have yielded both saurischian (titanosauriform, coelurosaur) and ornithischian (basal ornithopod, ankylosaurian) body fossils as well as dinosaurian eggs. We use photogrammetry and 3D imaging to reinterpret the sauropod tracks from Lishui City, which revealed the existence of trackways. The track record from three documented sites in Zhejiang Province includes avian and non-avian theropod, sauropod, ornithopod and pterosaur tracks. Previous work showed that the purported new bird ichnospecies Dongyangornipes sinensis is a synonym of Uhangrichnus chuni, while we here consider Pteraichnus dongyangensis as a nomen dubium. Such “provincial ichnotaxonomy” may mask similarities in the ichnofauna across large regions. In fact, we show that the ichnofauna is similar to that found in the Early Cretaceous elsewhere in China.

Upper Triassic and Middle Jurassic strata of the Xichang Basin in Sichuan Province, southwestern China, yielded important dinosaur ichnofossils. From the Xujiahe Formation of the Yiguojiao tracksite, we report a Late Triassic footprint assemblage in China and the first discovery of diagnostic Triassic sauropodomorph tracks in this region. The tracks share a number of features in common with the ichnogenera Eosauropus (Late Triassic) and Liujianpus (Early Jurassic). The neighboring Bingtu tracksite is stratigraphically younger (Shaximiao Formation, Middle Jurassic) and preserves small tridactyl theropod tracks that represent the first occurrence of the ichnotaxon Carmelopodus in China and Asia. While these tracks are morphologically comparable to those from the Middle Jurassic type locality in North America, the specimens from China show the proximal margin of the digit IV impression in a more cranial position, which may indicate a trackmaker with a relatively short metatarsal IV. In addition to the skeletal record, the Carmelopodus footprints document the presence of small theropods in the dinosaur fauna of the Middle Jurassic Shaximiao Formation.

Copyright of RAN - Revista Academia & Negocios is the property of RAN - Revista Academia & Negocios, Universidad de Concepcion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Vibrio parahaemolyticus is an autochthonous marine bacterial species comprising strains able to grow in broth containing bile salts at 37 °C, a condition seldom found in the ocean. However, this condition is used for isolation in the laboratory because it is considered a necessary property for pathogenesis. In this context, revealing how gene expression enables V. parahaemolyticus to adapt to this particular condition –common to almost all V. parahaemolyticus isolates- will improve our understanding of the biology of this important pathogen. To determine the genes of V. parahaemolyticus differentially expressed when growing in isolation condition (37 °C, 0.9% NaCl, and 0.04% bile salts) referred to those at the temperature and salt concentration prevailing in ocean south of Chile (marine-like condition; 12 °C, 3% NaCl, and absence of bile salts) we used high-throughput sequencing of RNA. Results Our results showed that in the isolation condition, among the 5034 genes annotated in the V. parahaemolyticus RIMD2210633 genome, 344 were upregulated and 433 downregulated referred to the marine-like condition, managing an adjusted P-value (Padj)