Dominio para las operaciones básicas y la resolución de problemas aritméticos de primer nivel en los estudiantes del primer grado del ciclo avanzado de los CEBA del distrito de Tambo – Huancayo – Perú - 2016.

El propósito del presente estudio fue establecer averiguaciones respecto a la relación que se pueda dar entre el dominio para las operaciones básicas y la resolución de problemas aritméticos del primer nivel, en estudiantes del primer grado del ciclo avanzado de los CEBA del distrito de Tambo – Huancayo – Perú. Considerando que en la actualidad la investigación educativa dirige parte de su atención al estudio de los procesos de enseñanza, estilos de enseñanza del docente, los dominios para las operaciones básicas y la resolución de problemas, considerado de gran importancia en la intención que los estudiantes lleguen a experimentar sus potencialidades y la utilidad de la matemática para su vida diaria, creemos que es sumamente importante someter a estudio a las variables del presente estudio. El estudio en mención, es de enfoque cuantitativo, hace uso del método hipotético científico, es de tipo sustantivo o de base, con diseño descriptivo correlacional, contó con una muestra de 50 estudiantes del primer grado del ciclo avanzado de los CEBA Mariscal Castilla, Luis Aguilar Romaní y Enrique Rosado Zárate del distrito de Tambo – Huancayo – Perú. Los instrumentos que permitieron recabar la información del caso, fueron: Prueba para evaluar los dominios para las operaciones básicas y la Prueba para evaluar la resolución de problemas aritméticos. El diseño estadístico utilizado para procesar la información, tuvo como base el paquete estadístico SPSS, versión 18. Los resultados a los cuales se arribó, son los siguientes: los puntaje promedios obtenidos en relación con la variable dominio para las operaciones básicas, son bajos; los puntaje promedios obtenidos en relación con la variable resolución de problemas aritméticos son bajos y no existe relación significativa entre el dominio para las operaciones básicas y la resolución de problemas aritméticos de primer nivel, en los estudiantes del primer grado del ciclo avanzado de los CEBA del distrito de Tambo – Huancayo – Perú.Universidad Nacional de Educación Enrique Guzmán y Valle. Escuela de Posgrado.Tesi

Dominio para las operaciones básicas y la resolución de problemas aritméticos de primer nivel en los estudiantes del primer grado del ciclo avanzado de los CEBA del distrito de Tambo – Huancayo – Perú - 2016.

El propósito del presente estudio fue establecer averiguaciones respecto a la relación que se pueda dar entre el dominio para las operaciones básicas y la resolución de problemas aritméticos del primer nivel, en estudiantes del primer grado del ciclo avanzado de los CEBA del distrito de Tambo – Huancayo – Perú. Considerando que en la actualidad la investigación educativa dirige parte de su atención al estudio de los procesos de enseñanza, estilos de enseñanza del docente, los dominios para las operaciones básicas y la resolución de problemas, considerado de gran importancia en la intención que los estudiantes lleguen a experimentar sus potencialidades y la utilidad de la matemática para su vida diaria, creemos que es sumamente importante someter a estudio a las variables del presente estudio. El estudio en mención, es de enfoque cuantitativo, hace uso del método hipotético científico, es de tipo sustantivo o de base, con diseño descriptivo correlacional, contó con una muestra de 50 estudiantes del primer grado del ciclo avanzado de los CEBA Mariscal Castilla, Luis Aguilar Romaní y Enrique Rosado Zárate del distrito de Tambo – Huancayo – Perú. Los instrumentos que permitieron recabar la información del caso, fueron: Prueba para evaluar los dominios para las operaciones básicas y la Prueba para evaluar la resolución de problemas aritméticos. El diseño estadístico utilizado para procesar la información, tuvo como base el paquete estadístico SPSS, versión 18. Los resultados a los cuales se arribó, son los siguientes: los puntaje promedios obtenidos en relación con la variable dominio para las operaciones básicas, son bajos; los puntaje promedios obtenidos en relación con la variable resolución de problemas aritméticos son bajos y no existe relación significativa entre el dominio para las operaciones básicas y la resolución de problemas aritméticos de primer nivel, en los estudiantes del primer grado del ciclo avanzado de los CEBA del distrito de Tambo – Huancayo – Perú.Universidad Nacional de Educación Enrique Guzmán y Valle. Escuela de Posgrado.Tesi

Effects of body plan evolution on the hydrodynamic drag and energy requirements of swimming in ichthyosaurs

Ichthyosaurs are an extinct group of fully marine tetrapods that were well adapted to aquatic locomotion. During their approximately 160 Myr existence, they evolved from elongate and serpentine forms into stockier, fish-like animals, convergent with sharks and dolphins. Here, we use computational fluid dynamics (CFD) to quantify the impact of this transition on the energy demands of ichthyosaur swimming for the first time. We run computational simulations of water flow using three-dimensional digital models of nine ichthyosaurs and an extant functional analogue, a bottlenose dolphin, providing the first quantitative evaluation of ichthyosaur hydrodynamics across phylogeny. Our results show that morphology did not have a major effect on the drag coefficient or the energy cost of steady swimming through geological time. We show that even the early ichthyosaurs produced low levels of drag for a given volume, comparable to those of a modern dolphin, and that deep ‘torpedo-shaped’ bodies did not reduce the cost of locomotion. Our analysis also provides important insight into the choice of scaling parameters for CFD applied to swimming mechanics, and underlines the great influence of body size evolution on ichthyosaur locomotion. A combination of large bodies and efficient swimming modes lowered the cost of steady swimming as ichthyosaurs became increasingly adapted to a pelagic existence

Raptorial appendages of the Cambrian apex predator Anomalocaris canadensis are built for soft prey and speed

The stem-group euarthropod Anomalocaris canadensis is one of the largest Cambrian animals and is often considered the quintessential apex predator of its time. This radiodont is commonly interpreted as a demersal hunter, responsible for inflicting injuries seen in benthic trilobites. However, controversy surrounds the ability of A. canadensis to use its spinose frontal appendages to masticate or even manipulate biomineralized prey. Here, we apply a new integrative computational approach, combining threedimensional digital modelling, kinematics, finite-element analysis (FEA) and computational fluid dynamics (CFD) to rigorously analyse an A. canadensis feeding appendage and test its morphofunctional limits. These models corroborate a raptorial function, but expose inconsistencies with a capacity for durophagy. In particular, FEA results show that certain parts of the appendage would have experienced high degrees of plastic deformation, especially at the endites, the points of impact with prey. The CFD results demonstrate that outstretched appendages produced low drag and hence represented the optimal orientation for speed, permitting acceleration bursts to capture prey. These data, when combined with evidence regarding the functional morphology of its oral cone, eyes, body flaps and tail fan, suggest that A. canadensis was an agile nektonic predator that fed on soft-bodied animals swimming in a well-lit water column above the benthos. The lifestyle of A. canadensis and that of other radiodonts, including plausible durophages, suggests that niche partitioning across this clade influenced the dynamics of Cambrian food webs, impacting on a diverse array of organisms at different sizes, tiers and trophic levels

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

SusanaGutarra/Plesiosaur-hydrodynamics-evolution: Latest updated release (version 1.3)

Data and files for "Large size in aquatic tetrapods compensates for high drag caused by extreme body proportions". Latest updated release with corrected Supplementary Data 1 (Version 1.3.)

The locomotion of extinct secondarily aquatic tetrapods

The colonisation of freshwater and marine ecosystems by land vertebrates has repeatedly occurred in amphibians, reptiles, birds and mammals over the course of 300 million years. Functional interpretations of the fossil record are crucial to understanding the forces shaping these evolutionary transitions. Secondarily aquatic tetrapods have acquired a suite of anatomical, physiological and behavioural adaptations to locomotion in water. However, much of this information is lost for extinct clades, with fossil evidence often restricted to osteological data and a few extraordinary specimens with soft tissue preservation. Traditionally, functional morphology in fossil secondarily aquatic tetrapods was investigated through comparative anatomy and correlation with living functional analogues. However, in the last two decades, biomechanics in palaeobiology has experienced a remarkable methodological shift. Anatomy-based approaches are increasingly rigorous, informed by quantitative techniques for analysing shape. Moreover, the incorporation of physics-based methods has enabled objective tests of functional hypotheses, revealing the importance of hydrodynamic forces as drivers of evolutionary innovation and adaptation. Here, we present an overview of the latest research on the locomotion of extinct secondarily aquatic tetrapods, with a focus on amniotes, highlighting the state-of-the-art experimental approaches used in this field. We discuss the suitability of these techniques for exploring different aspects of locomotory adaptation, analysing their advantages and limitations and laying out recommendations for their application, with the aim to inform future experimental strategies. Furthermore, we outline some unexplored research avenues that have been successfully deployed in other areas of palaeobiomechanical research, such as the use of dynamic models in feeding mechanics and terrestrial locomotion, thus providing a new methodological synthesis for the field of locomotory biomechanics in extinct secondarily aquatic vertebrates. Advances in imaging technology and three-dimensional modelling software, new developments in robotics, and increased availability and awareness of numerical methods like computational fluid dynamics make this an exciting time for analysing form and function in ancient vertebrates.Copyright© 2021 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society. This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited. The attached document is the authors’ final accepted/submitted version of the journal article. You are advised to consult the publisher’s version if you wish to cite from i