The transcription factor Zic4 promotes tentacle formation and prevents epithelial transdifferentiation in Hydra.

The molecular mechanisms that maintain cellular identities and prevent dedifferentiation or transdifferentiation remain mysterious. However, both processes are transiently used during animal regeneration. Therefore, organisms that regenerate their organs, appendages, or even their whole body offer a fruitful paradigm to investigate the regulation of cell fate stability. Here, we used Hydra as a model system and show that Zic4, whose expression is controlled by Wnt3/ß-catenin signaling and the Sp5 transcription factor, plays a key role in tentacle formation and tentacle maintenance. Reducing Zic4 expression suffices to induce transdifferentiation of tentacle epithelial cells into foot epithelial cells. This switch requires the reentry of tentacle battery cells into the cell cycle without cell division and is accompanied by degeneration of nematocytes embedded in these cells. These results indicate that maintenance of cell fate by a Wnt-controlled mechanism is a key process both during homeostasis and during regeneration.

Arnold tongue entrainment reveals dynamical principles of the embryonic segmentation clock.

Living systems exhibit an unmatched complexity, due to countless, entangled interactions across scales. Here, we aim to understand a complex system, that is, segmentation timing in mouse embryos, without a reference to these detailed interactions. To this end, we develop a coarse-grained approach, in which theory guides the experimental identification of the segmentation clock entrainment responses. We demonstrate period- and phase-locking of the segmentation clock across a wide range of entrainment parameters, including higher-order coupling. These quantifications allow to derive the phase response curve (PRC) and Arnold tongues of the segmentation clock, revealing its essential dynamical properties. Our results indicate that the somite segmentation clock has characteristics reminiscent of a highly non-linear oscillator close to an infinite period bifurcation and suggests the presence of long-term feedbacks. Combined, this coarse-grained theoretical-experimental approach reveals how we can derive simple, essential features of a highly complex dynamical system, providing precise experimental control over the pace and rhythm of the somite segmentation clock.

Near-zero cohesion and loose packing of Bennu's near subsurface revealed by spacecraft contact.

When the OSIRIS-REx spacecraft pressed its sample collection mechanism into the surface of Bennu, it provided a direct test of the poorly understood near-subsurface physical properties of rubble-pile asteroids, which consist of rock fragments at rest in microgravity. Here, we find that the forces measured by the spacecraft are best modeled as a granular bed with near-zero cohesion that is half as dense as the bulk asteroid. The low gravity of a small rubble-pile asteroid such as Bennu effectively weakens its near subsurface by not compressing the upper layers, thereby minimizing the influence of interparticle cohesion on surface geology. The underdensity and weak near subsurface should be global properties of Bennu and not localized to the contact point.

Gasto energético e intensidad del entrenamiento de porrismo: Un estudio descriptivo / Energy Expenditure and Intensity of Cheerleading Training: A Descriptive Study

Resumen objetivo del presente estudio fue aclarar las siguientes preguntas: ¿son equivalentes los gastos energéticos en términos de METs de los entrenamientos de porrismo y lo reportado por el compendio de gasto energético de Ainsworth et al. (2011)? ¿Hay diferencias estadísticamente significativas del gasto energético e intensidad del entrenamiento de porrismo al comparar diferentes categorías de rendimiento y sexo? Metodología: Se midió el gasto energético y la intensidad durante una hora de entrenamientos de porrismo, a una muestra compuesta por 103 porristas (hombres = 55; mujeres = 48), los cuales pertenecen a tres equipos all stars y dos selecciones nacionales de Costa Rica. Resultados: No se encontraron diferencias entre el valor reportado por Ainsworth et al. (2011) y los entrenamientos de porrismo (6 METs vs 5.8 METs, t = -1.7, p = 0.092). Se evidenció una interacción significativa del gasto energético (kcal) entre sexo y categoría de rendimiento. Conclusiones: El gasto energético en términos de METs de los entrenamientos de porrismo es equivalente a lo reportado por Ainsworth et al. (2011). Los hombres con categoría "alta" de rendimiento tuvieron un gasto energético significativamente mayor (p<0.05*) comparado con los hombres de categoría "media" o "baja" y con las mujeres de las tres categorías. No se encontraron diferencias en términos de intensidad al comparar sexo y categoría de rendimiento.

Abstract The objective of the present study was to answer the following questions: are the energy expenditure equivalent in terms of METs of cheerleading training sessions and what Ainsworth et al. (2011) show? Are there statistically significant differences in the energy expenditure and intensity of cheerleading training when comparing different performance and sex categories? Methodology: Energy expenditure and intensity were measured during one hour of cheerleading training for a sample of 103 cheerleaders (men = 55; women = 48), who belong to three all-star teams and two national teams from Costa Rica. Results: No differences were found between the value reported by Ainsworth et al. (2011) and cheerleading workouts (6 METs vs. 5.8 METs, t = -1.7, p = 0.092). A significant interaction of energy expenditure (kcal) between sex and performance category was evident. Conclusions: The energy expenditure in terms of METs for cheerleading workouts is equivalent to that reported by Ainsworth et al. (2011). Men with a "high" performance category had significantly higher energy expenditure (p <0.05 *) compared to men with a "medium" or "low" category and with women in all three categories. No differences were found in terms of intensity when comparing sex and performance category.

Resumo O objetivo do presente estudo foi para esclarecer as seguintes questões: os gastos de energia são equivalentes em termos de METs de treinamento de equipe de torcida e os relatados pelo compêndio de gasto de energia de Ainsworth et al. (2011). Existem diferenças estatisticamente significativas no gasto de energia e na intensidade do treinamento da equipe ao comparar diferentes categorias de desempenho e gênero? Metodologia: o gasto energético e a intensidade foram medidos durante uma hora de treinamento da equipe de torcida, em uma amostra composta por 103 líderes de torcida (homens = 55; mulheres = 48), pertencentes a três equipes. todas as estrelas e duas seleções da Costa Rica. Resultados não foram encontradas diferenças entre o valor relatado por Ainsworth et al. (2011) e treinos de equipes de torcida (6 METs vs 5,8 METs, t = -1,7, p = 0,092). Evidenciou-se interação significativa do gasto energético (kcal) entre sexo e categoria de desempenho. Conclusão: O gasto energético em termos de METs do treinamento da equipe de torcida é equivalente ao relatado por Ainsworth et al. (2011). Os homens na categoria "alto" de desempenho tiveram um gasto energético significativamente maior (p <0,05 *) em comparação com os homens na categoria "médio" ou "baixo" e com as mulheres nas três categorias. Não foram encontradas diferenças em termos de intensidade ao comparar sexo e categoria de desempenho.

Efecto de diferentes tipos de entrenamiento físico en la altura de salto de gimnastas: meta-análisis / Effect of different types of physical training on gymnastics jump height: meta-analysis

Resumen Ulloa-Sánchez, P., y Hernández Elizondo, J. (2021). Efecto de diferentes tipos de entrenamiento físico en la altura de salto de gimnastas: meta-análisis. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 19(1), 1-35. El principal objetivo del presente estudio fue determinar el efecto de diferentes tipos de entrenamiento físico en la altura de salto de gimnastas bajo la metodología de meta-análisis. Se siguieron los lineamientos PRISMA; las bases de datos electrónicas consultadas en la búsqueda fueron EBSCOhost (SPORTDiscus, MEDLINE, Academic Search Complete, E-Journals, OmniFile Full Text Select (H.W. Wilson), Web of Science, Scopus, SciencDirect, Research Gate y Pubmed para identificar los artículos relevantes que investigaron la aplicación de un entrenamiento físico y evaluaron la altura salto en gimnastas antes y después de la intervención. Después del proceso de selección de estudios, y a partir de los criterios de inclusión, se codificaron 29 estudios individuales y se codificaron 157 tamaños de efecto (TE) individuales. La muestra total de sujetos fue 688 gimnastas. El grupo experimental mostró un TE global de bajo a moderado y significativo (TE = 0.33, . <0 .001*). Se evidenció una diferencia significativa (. = 0.001*) entre los tipos de entrenamiento; el análisis Post Hoc mostró que el TE global del entrenamiento de pliometría (TE = 0.85, . <0.001*) fue mayor al de estiramiento (TE = -0.07, . = 0.56) y "otros" (TE = 0.48, . < 0.001*), pero no al de vibración (TE = 0.54, . < 0.001*); además, el TE global de tipo de estiramiento fue significativamente menor a todos los tipos de entrenamiento. Se concluyó que el tipo de entrenamiento que mostró el mayor TE global fue pliometría, seguido por el entrenamiento en plataforma vibratoria. Parece que el estiramiento no se relaciona significativamente con la altura de salto de gimnastas.

Abstract Ulloa-Sánchez, P., & Hernández Elizondo, J. (2021). Effect of different types of physical training on gymnastics jump height: meta-analysis. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 19(1), 1-35. The main objective of this study was to determine the effect of different types of physical training on gymnastics jump height under the meta-analysis methodology. The PRISMA guidelines were followed. The electronic databases used in the search were EBSCOhost (SPORTDiscus, MEDLINE, Academic Search Complete, E-Journals, OmniFile Full Text Select (HW Wilson), Web of Science, Scopus, SciencDirect, Research Gate, and Pubmed in order to identify relevant articles regarding the use of physical training and the assessment of jump height in gymnasts before and after intervention. Based on the inclusion criteria, 29 individual studies and 157 individual effect sizes (TE) were coded. The total sample included 688 gymnasts. The overall TE of the experimental group was low to moderate and significant (TE = 0.33, . < 0.001*). A significant difference was evidenced (p = 0.001*) between the types of training. The Post Hoc analysis showed that the global TE of plyometrics training (TE = 0.85, . < 0.001*) was higher than that of stretching (TE = -0.07, . = 0.56) and "others" (TE = 0.48, . < 0.001*), but not than vibration (TE = 0.54, . < 0.001*). Furthermore, the overall TE of stretching was significantly lower than all the other types of training. It was concluded that the type of training with the highest overall TE was plyometrics, followed by vibrational platform training. Stretching does not appear to be significantly related to gymnastics jump height.

Resumo Ulloa-Sánchez, P., e Hernández Elizondo, J. (2021). Efeito de diferentes tipos de treinamento físico na altura do salto de ginastas: metanálise. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 19(1), 1-35. Este estudo teve como principal objetivo determinar o efeito de diferentes tipos de treinamento físico na altura de salto de ginastas, por meio da metodologia de metanálise. Foram seguidas as diretrizes do PRISMA e consultadas, na busca, as bases de dados eletrônicas: EBSCOhost (SPORTDiscus, MEDLINE, Academic Search Complete, E-Journals, OmniFile Full Text Select (HW Wilson), Web of Science, Scopus, SciencDirect, Research Gate e Pubmed, para identificar artigos relevantes que investigaram a aplicação de um treinamento físico e avaliaram a altura do salto em ginastas antes e depois da intervenção. Após o processo de seleção dos estudos e com base nos critérios de inclusão, foram codificados 29 estudos individuais e 157 tamanhos do efeito (TE) individuais. A amostra total de sujeitos foi de 688 ginastas. O grupo experimental apresentou um TE global de baixo a moderado e significativo (TE = 0,33, . < 0,001*). Diferença significativa (. = 0,001*) entre os tipos de treinamento; a análise Post Hoc mostrou que o TE global do treinamento de pliometria (TE = 0,85, . < 0,001*) foi maior do que o do alongamento (TE = -0,07, p = 0,56) e "outros" (TE = 0,48, . < 0,001 *), mas não maior do que o de vibração (TE = 0,54, . < 0,001 *); além disso, o TE global de tipo de alongamento foi significativamente menor do que todos os tipos de treinamento. Concluiu-se, portanto, que o tipo de treinamento que apresentou o maior TE geral foi o de pliometria, seguida do treinamento em plataforma vibracional. O alongamento não parece estar significativamente relacionado à altura de salto de ginastas.

Engineering complex communities by directed evolution.

Directed evolution has been used for decades to engineer biological systems at or below the organismal level. Above the organismal level, a small number of studies have attempted to artificially select microbial ecosystems, with uneven and generally modest success. Our theoretical understanding of artificial ecosystem selection is limited, particularly for large assemblages of asexual organisms, and we know little about designing efficient methods to direct their evolution. Here, we have developed a flexible modelling framework that allows us to systematically probe any arbitrary selection strategy on any arbitrary set of communities and selected functions. By artificially selecting hundreds of in silico microbial metacommunities under identical conditions, we first show that the main breeding methods used to date, which do not necessarily let communities reach their ecological equilibrium, are outperformed by a simple screen of sufficiently mature communities. We then identify a range of alternative directed evolution strategies that, particularly when applied in combination, are well suited for the top-down engineering of large, diverse and stable microbial consortia. Our results emphasize that directed evolution allows an ecological structure-function landscape to be navigated in search of dynamically stable and ecologically resilient communities with desired quantitative attributes.

El efecto agudo de diferentes tipos de estiramiento sobre la altura de salto de gimnastas: revisión sistemática / The Acute Effect of Different Types of Stretching on thee Height of Jump of Gymnasts: Systematic Review

Resumen Objetivo: El principal objetivo del presente estudio fue analizar el efecto de diferentes tipos de estiramiento sobre la altura de salto de gimnastas. Metodología: Se consultaron las siguientes bases de datos: EBSCOhost (SPORTDiscus, MEDLINE, Academic Search Complete, E-Journals, Fuente Académica Premier, International Bibliography of Theatre & Dance with Full Text y PsycARTICLES) y Pubmed. Se utilizó la siguiente frase bolena: (stretch OR static stretch OR dynamic stretch OR ballistic stretch OR proprioceptive neuromuscular facilitation) AND (jumping OR vertical jump OR countermovement jump OR explosive strength OR performance) AND (gymnasts OR gymnastics). Se establecieron los siguientes criterios de elegibilidad: Que posea un diseño experimental, cuasiexperimental o preexperimental. Que la muestra sea de gimnastas. Explicación de metodología clara. Buena descripción del método de estiramiento aplicado. Resultados: Se incluyó un total de 10 estudios individuales, la muestra total entre esa cantidad de estudios fue de 226 sujetos y, la cantidad de intervenciones fue de 16. El 75 % de las intervenciones tuvo un efecto no significativo (p>.05), mientras que el otro 25 % tuvo un efecto significativo (p<.05*) sobre la altura de salto. Ese porcentaje de efectos significativos corresponde a dos aumentos y dos disminuciones de la altura de salto. Conclusiones: La mayoría de las intervenciones indica que la altura de salto de gimnastas no se ve afectada por los diferentes tipos de estiramiento (sólo el 12.5 % de las intervenciones refutan esta afirmación), incluso, dos intervenciones mostraron aumentos de la capacidad de salto durante un tiempo determinado.

Abstract Objective: This study mainly aimed to analyze the effect of different types of stretching on gymnasts' jump height. Methodology: The following databases were consulted: Pubmed and EBSCOhost (SPORTDiscus, MEDLINE, Academic Search Complete, E-Journals, Premier Academic Source, International Bibliography of Theater & Dance with Full Text, and PsycARTICLES). The following boolean phrase was used: (stretch OR static stretch OR dynamic stretch OR ballistic stretch OR proprioceptive neuromuscular facilitation) AND (jumping OR vertical jump OR countermovement jump OR explosive strength OR performance) AND (gymnasts OR gymnastics). The following eligibility criteria were established: to use an experimental, quasi-experimental, or pre-experimental design; to conduct the study on a sample of gymnasts; to explain the methodology clearly; a good description of the stretching method applied. Results: Ten individual studies were included, the total sample among those studies was 226 individuals, and the number of interventions was 16. A 75% of the interventions had a non-significant effect (p> 0.05), while the other 25% had a significant effect (p <0.05 *) on the jump height. The percentage of significant effects corresponds to two increases and two decreases in jump height. Conclusions: Most interventions show that gymnasts' jump height is not affected by different types of stretching (only 12.5% of interventions refute this claim); even two interventions showed increases in jumping capacity during a set time.

Resumo Objetivo: O objetivo principal deste estudo foi analisar o efeito de diferentes tipos de alongamentos na altura de salto de ginastas. Metodologia: Foram consultadas as seguintes bases de dados: EBSCOhost (SPORTDiscus, MEDLINE, Academic Search Complete, E-Journals, Premier Academic Source, International Bibliography of Theatre & Dance with Full Text and PsycARTICLES) e Pubmed. Foi utilizada a seguinte frase bolena: (estiramento ou estiramento estático, estiramento dinâmico, estiramento balístico, facilitação neuromuscular proprioceptiva) e (salto, ou salto vertical, salto de movimento contrário, ou força explosiva ou desempenho) e (ginastas ou ginástica). Foram estabelecidos os seguintes critérios de elegibilidade: desenho experimental, quase-experimental ou pré-experimental. A amostra deve ser de ginastas. Explicação clara da metodologia. Boa descrição do método de alongamento aplicado. Resultados: Foram incluídos 10 estudos individuais, a amostra total entre esse número de estudos foi de 226 sujeitos e, o número de intervenções foi de 16. 75% das intervenções tiveram um efeito não significativo (p>,05), enquanto os outros 25% tiveram um efeito significativo (p<.05*) sobre a altura do salto. Essa porcentagem de efeitos significativos corresponde a dois aumentos e duas diminuições na altura do salto. Conclusões : A maioria das intervenções indica que a altura das ginastas não é afetada pelos diferentes tipos de alongamento (apenas 12,5% das intervenções refutam essa afirmação), mesmo duas intervenções mostraram aumento na capacidade de saltar durante um certo tempo.

Ricochets on Asteroids: Experimental study of low velocity grazing impacts into granular media.

Spin off events and impacts can eject boulders from an asteroid surface and rubble pile asteroids can accumulate from debris following a collision between large asteroids. These processes produce a population of gravitational bound objects in orbit that can impact an asteroid surface at low velocity and with a distribution of impact angles. We present laboratory experiments of low velocity spherical projectiles into a fine granular medium, sand. We delineate velocity and impact angles giving ricochets, those giving projectiles that roll-out from the impact crater and those that stop within their impact crater. With high speed camera images and fluorescent markers on the projectiles we track spin and projectile trajectories during impact. We find that the projectile only reaches a rolling without slipping condition well after the marble has reached peak penetration depth. The required friction coefficient during the penetration phase of impact is 4-5 times lower than that of the sand suggesting that the sand is fluidized near the projectile surface during penetration. We find that the critical grazing impact critical angle dividing ricochets from roll-outs, increases with increasing impact velocity. The critical angles for ricochet and for roll-out as a function of velocity can be matched by an empirical model during the rebound phase that balances a lift force against gravity. We estimate constraints on projectile radius, velocity and impact angle that would allow projectiles on asteroids to ricochet or roll away from impact, finally coming to rest distant from their initial impact sites.

El efecto agudo del entrenamiento en trampolín sobre la estabilidad, la altura de salto y la velocidad de carrera en 20 metros de porristas / Acute effect of trampoline training on stability, jump height, and speed in 20-meter sprints in cheerleaders

Resumen El efecto agudo del entrenamiento en trampolín sobre la estabilidad, la altura de salto y la velocidad de carrera en 20 metros de porristas. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 18(1), 1-18. El principal objetivo del estudio es analizar el efecto agudo del entrenamiento en trampolín (ET) sobre la estabilidad, altura de salto y velocidad de carrera en 20 m de porristas. Se reclutaron 53 sujetos (18 hombres y 35 mujeres), que pertenecen al programa de porrismo Pura Vida Athletics (Tibás, Costa Rica). Se conformaron aleatoriamente tres grupos: grupo trampolín (GT), grupo control (GC) y grupo entrenamiento normal (GEN). El GT realizó un entrenamiento de trampolín (ET) tradicional (duración aproximada de 45 min; intensidad de 75-85% de la frecuencia cardiaca máxima). Se realizaron mediciones pre test y post test de la estabilidad (centro de presión), velocidad en 20 m y altura de salto (CMJ). Respecto a la estabilidad, en bipedestación el GT empeoró significativamente (p0.05) y el GEN (p>0.05) no tuvieron un cambio significativo. Como conclusiones, se evidenció una disminución significativa de la estabilidad del GT en bipedestación y, en los elementos de stunt liberty, awesome y arebesque. La altura del CMJ del GT tuvo una disminución no significativa. La velocidad en 20 m del GT fue significativamente menor después del ET.

Abstract Acute effect of trampoline training on stability, jump height, and speed in 20-meter sprints in cheerleaders. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 18(1), 1-18. A total of 53 subjects were recruited (18 men and 35 women) belonging to the Pura Vida Athletics Cheerleading program (Tibás, Costa Rica). Three groups were randomly formed: Trampoline Group (GT), Control Group (GC), and Normal Training Group (GEN). GT followed a traditional ET treatment (approximate duration 45 min; intensity 75-85% of maximum heart rate). Pre-test and post-test measurements of stability (pressure center), speed in 20-m sprints, and jump height (CMJ) were conducted. Regarding stability, GT significantly worsened (p0.05) and GEN (p>0.05) did not have a significant change. In conclusion, there was a significant decrease in stability of GT in a bipedal stance and in Liberty, Awesome and Arabesque stunts. Height of CMJ of GT had a non-significant decrease, while speed in 20-m sprints of GT was significantly lower after ET.

Resumo O efeito agudo do treinamento em trampolim sobre estabilidade, altura de salto e velocidade em corrida de 20 metros de líderes de torcida. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 18(1), 1-18. O principal objetivo do estudo é analisar o efeito agudo do treinamento em trampolim (ET) sobre estabilidade, altura de salto e velocidade em corrida de 20 m de líderes de torcida. Foram recrutados 53 sujeitos (18 homens e 35 mulheres), pertencentes ao programa Pura Vida Athletics (Tibás, Costa Rica). Três grupos foram formados aleatoriamente: Grupo Trampolim (GT), Grupo Controle (GC) e Grupo de Treinamento Normal (GEN). O GT realizou um treinamento de trampolim (ET) tradicional (com uma duração aproximada de 45 min e intensidade de 75-85% da frequência cardíaca máxima). Foram realizadas medições pré-teste e pós-teste de estabilidade (centro de pressão), velocidade de 20 metros e altura de salto (CMJ). Com relação à estabilidade, em bipedestação, o GT piorou significativamente (p 0,05) e o GEN (p> 0,05) não apresentaram uma alteração significativa. Como conclusão, ficou evidente uma diminuição significativa na estabilidade do GT em bipedestação e nos elementos de stunt liberty, awesome e arebesque. A altura do CMJ do GT teve uma diminuição não significativa. A velocidade de 20 m do GT foi significativamente menor após o ET.

Impact Excitation of a Seismic Pulse and Vibrational Normal Modes on Asteroid Bennu and Associated Slumping of Regolith.

We consider an impact on an asteroid that is energetic enough to cause resurfacing by seismic reverberation and just below the catastrophic disruption threshold, assuming that seismic waves are not rapidly attenuated. In asteroids with diameter less than 1 km we identify a regime where rare energetic impactors can excite seismic waves with frequencies near those of the asteroid's slowest normal modes. In this regime, the distribution of seismic reverberation is not evenly distributed across the body surface. With mass-spring model elastic simulations, we model impact excitation of seismic waves with a force pulse exerted on the surface and using three different asteroid shape models. The simulations exhibit antipodal focusing and normal mode excitation. If the impulse excited vibrational energy is long lasting, vibrations are highest at impact point, its antipode and at high surface elevations such as an equatorial ridge. A near equatorial impact launches a seismic impulse on a non-spherical body that can be focused on two additional points on an the equatorial ridge. We explore simple flow models for the morphology of vibration induced surface slumping. We find that the initial seismic pulse is unlikely to cause large shape changes. Long lasting seismic reverberation on Bennu caused by a near equatorial impact could have raised the height of its equatorial ridge by a few meters and raised two peaks on it, one near impact site and the other near its antipode.

Simulations of wobble damping in viscoelastic rotators.

Using a damped mass-spring model, we simulate wobble of spinning homogeneous viscoelastic ellipsoids undergoing non-principal axis rotation. Energy damping rates are measured for oblate and prolate bodies with different spin rates, spin states, viscoelastic relaxation timescales, axis ratios, and strengths. Analytical models using a quality factor by Breiter et al. (2012) and for the Maxwell rheology by Frouard & Efroimsky (2018) match our numerical measurements of the energy dissipation rate after we modify their predictions for the numerically simulated Kelvin-Voigt rheology. Simulations of nearly spherical but wobbling bodies with hard and soft cores show that the energy dissipation rate is more sensitive to the material properties in the core than near the surface.

Publisher Correction: Genomes of 13 domesticated and wild rice relatives highlight genetic conservation, turnover and innovation across the genus Oryza.

This article was not made open access when initially published online, which was corrected before print publication. In addition, ORCID links were missing for 12 authors and have been added to the HTML and PDF versions of the article.

Genomes of 13 domesticated and wild rice relatives highlight genetic conservation, turnover and innovation across the genus Oryza.

The genus Oryza is a model system for the study of molecular evolution over time scales ranging from a few thousand to 15 million years. Using 13 reference genomes spanning the Oryza species tree, we show that despite few large-scale chromosomal rearrangements rapid species diversification is mirrored by lineage-specific emergence and turnover of many novel elements, including transposons, and potential new coding and noncoding genes. Our study resolves controversial areas of the Oryza phylogeny, showing a complex history of introgression among different chromosomes in the young 'AA' subclade containing the two domesticated species. This study highlights the prevalence of functionally coupled disease resistance genes and identifies many new haplotypes of potential use for future crop protection. Finally, this study marks a milestone in modern rice research with the release of a complete long-read assembly of IR 8 'Miracle Rice', which relieved famine and drove the Green Revolution in Asia 50 years ago.

The genome sequence of African rice (Oryza glaberrima) and evidence for independent domestication.

The cultivation of rice in Africa dates back more than 3,000 years. Interestingly, African rice is not of the same origin as Asian rice (Oryza sativa L.) but rather is an entirely different species (i.e., Oryza glaberrima Steud.). Here we present a high-quality assembly and annotation of the O. glaberrima genome and detailed analyses of its evolutionary history of domestication and selection. Population genomics analyses of 20 O. glaberrima and 94 Oryza barthii accessions support the hypothesis that O. glaberrima was domesticated in a single region along the Niger river as opposed to noncentric domestication events across Africa. We detected evidence for artificial selection at a genome-wide scale, as well as with a set of O. glaberrima genes orthologous to O. sativa genes that are known to be associated with domestication, thus indicating convergent yet independent selection of a common set of genes during two geographically and culturally distinct domestication processes.

In vivo anti-inflammatory and anti-ulcerogenic activities of extracts from wild growing and in vitro plants of Castilleja tenuiflora Benth. (Orobanchaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Castilleja tenuiflora Benth. (Orobanchaceae) is a perennial shrub used since the 16(th) century in Mexican traditional medicine for the treatment of a number of health disorders including inflammation, stomach pain and tumors. The aim of the present study was to evaluate the cytotoxic, anti-inflammatory and anti-ulcerogenic activities of ethyl acetate (EaE), methanol (ME) and aqueous extracts (AE) of Castilleja tenuiflora wild grown (CtW) and in vitro plants (CtIv). MATERIAL AND METHOD: Phytochemical analysis of the phenylethanoid glycoside (PhG) and iridoid glycoside (IG) components was carried out by chromatographic methods. In vitro cytotoxic activity of the extracts was evaluated in the following four carcinoma cell lines: colon (HF-6), breast (MCF-7), prostate (PC-3), and nasopharyngeal (KB). The topical anti-inflammatory activity was evaluated in mouse ear edema induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Anti-ulcerogenic activity was evaluated in rats using an absolute ethanol-induced acute gastric ulcer model. RESULTS: The main compounds in the extracts were isoverbascoside, verbascoside and aucubin and their concentration depended both on the solvent used and on the plant material origin. None of the extracts showed cytotoxicity against the tested cell lines. In contrast, CtWEaE, CtWAE and CtIvEaE (1.6 mg/ear) showed moderate anti-inflammatory activity similar to dexamethasone (1 mg/ear) with a 38.2, 39.3 and 49.1% decrease of inflammation, respectively. CtWEaE and CtIvEaE (100 mg/kg) showed high anti-ulcerogenic activity with 88.3 and 83.1% inhibition, respectively, compared to famotidine (20 mg/kg, 32.8% inhibition). CONCLUSION: Castilleja tenuiflora extracts provided significant gastric protection in an acute ulcer induction model and topical anti-inflammatory activity in a mouse ear edema model. These activities are related to verbascoside and may explain the traditional use of Castilleja tenuiflora in the treatment of anti-inflammatory and gastrointestinal disorders. Cultured Castilleja tenuiflora plants (in vitro) exhibited pharmacological activities and also have the potential to produce bioactive compounds.

Ácidos grasos omega-3 como coadyuvantes del tratamiento antidepresivo y sus efectos sobre el factor neurotrófico derivado del cerebro en suero y en células mononucleares / Omega-3 fatty acids as adjunctive of antidpressant therapy and its effects on brain-derived neurotrophic factor in serum, monocytes and lymphocytes

El estrés disminuye el factor neurotrófico derivado del cerebro (BDNF) en el hipocampo; los antidepresivos y los ácidos grasos omega-3 podrían aumentarlo. En pacientes con depresión mayor, investigamos la respuesta clínica a un antidepresivo solo o con ácido eicosapentanoico (EPA), y su influencia sobre los niveles de BDNF. Veinte pacientes se diagnósticaron según el DSM-IV-TR; evaluamos la respuesta con la Escala de Hamilton para Depresión (HAM-D). Los controles fueron 15 sujetos sanos. Los pacientes se distribuyeron en 2 grupos: uno recibió fluoxetina 20 mg/día y EPA 3.000 mg/día, y otro con fuoxetina 20 mg/día y placebo, durante 8 semanas. Se tomaron muestras de sangre en las semanas 0 y 8 para obtener suero, sin anticuoagulante, para medir los niveles de BDNF, y para aislamiento de células mononucleares, con heparina, para la localización inmunocitoquímica de BDNF. Diez pacientes no continuaron por diferentes causas. De los 10 restantes, 5 recibieron EPA y 5, placebo. El BDNF sérico disminuyó despúes de tratamiento en ambos grupos, más evidente en el grupo con EPA en el análisis pareado. El porcentaje de células mononucleares que expresaron BDNF fue inferior en los pacientes y aumentó después de los tratamientos. Por otra parte, las células con BDNF, las cuales estaban bajas en los deprimidos, aumentaron después de los tratamientos, lo que indica que en estás, el papel del tratamiento, especialmente con la combinación del antidepresivo y el ácido en cuestión, las modificaciones en el BDNF son más evidentes. A pesar de la limitante que constituye la inclusión de los sujetos diagnósticados, más la permanencia de los incluidos, los resultados significativos señalan un efecto beneficiosos del uso de EPA en la depresión mayor

Stress is associated with a decreased expression of brainderived neurotrophic factor (BDNF) in the hippocampus. Antidepressants and omega-3 fatty acids might increase circulating BDNF. This research was done to evaluate, in major depression patients, the possible differences in clinical response to an antidepressant alone or in combination with eicosapentaenoic acid (EPA), and their influence on BDNF levels. Nineteen patients were diagnosed according to DSM-IV-TR criteria; severity and response was evaluated by Hamilton Depression Rating Scale (HAM-D). Control group was composed of 15 healthy subjects. Patients were randomized on a double-blind bassis in two groups: one recived fluoxetine 20 mg/day and EPA 3,000 mg/day, and the other one fluoxetine 20 mg/day an placebo, during 8 weeks. Blood samples were taken for obtaining serum and for isolating monocytes and lymphocytes at weeks 0 and 8. Ten patients dropped out for different causes. Of the remaining 9 subjetcs, 4 recived EPA and 5 got placebo. The percentage of mononuclear cells expressing BDNF was lower in patients, and it was significantly increased after the treatments. EPA seems to augment the clinical response. In depressed, after treatment, there was a lower content of serum BDNF. Moreover, mononuclear cells with BDNF, which were lower in this group of depressed, increased after the treatments, indicating that in cells the modulation of BDNF by antidepressants is more evident

Clinical features, outcomes, and costs of a conjunctivitis outbreak caused by the ST448 strain of Streptococcus pneumoniae.

PURPOSE: An outbreak of pneumococcal conjunctivitis occurred at Dartmouth College in 2002. We describe the clinical features, outcomes, and costs associated with this outbreak. METHODS: Six hundred ninety-eight students were diagnosed with conjunctivitis; culture of conjunctival discharge was obtained for 254. A screening protocol was used to evaluate 67 patients. A retrospective survey was offered to all 698 cases and follow-up clinical examination to all patients with culture-confirmed infection (n = 110). Local ophthalmology offices were contacted to develop a cost analysis. The college health service provided conjunctivitis data for nonoutbreak years. RESULTS: Of 67 patients evaluated using the screening protocol, findings associated with culture-confirmed Streptococcus pneumoniae conjunctivitis (P < 0.01) were red eye visible from 2 feet, any type of conjunctival discharge, obscuration of tarsal conjunctival blood vessels, and chemosis. Two hundred thirty-two students responded to our retrospective survey; 89% reported bilateral eye involvement; 96% received topical antibiotics and noted symptom improvement within 3 days of treatment. No ocular sequelae were identified as a result of this infection. No recurrent outbreaks have occurred at Dartmouth since the initial event. The estimated cost of this outbreak including evaluations, cultures, and antibiotics ranged from $66,468 to $120,583. CONCLUSIONS: The ST448 strain of S. pneumoniae caused a disruptive outbreak of conjunctivitis at Dartmouth College. A screening protocol was effective at identifying culture-positive cases. Although most culture-positive patients experienced bilateral conjunctivitis, the clinical course was mild with quick resolution of symptoms after initiating antibiotics and no ocular sequelae.

A preliminary in vivo assessment of higher-order aberrations induced by a silicone hydrogel monofocal contact lens.

PURPOSE: To evaluate the effect of negatively powered soft contact lenses on ocular higher-order aberrations (HOAs). METHODS: HOA measurements were performed with fixed optical zones of 4.0 and 6.0 mm on 20 eyes of 10 participants before and minutes after wearing extended-wear Focus NIGHT & DAY contact lenses. For each eye, three contact lens powers were used: -2.00 diopters (D), -4.00 D, and a power equal to the spherical equivalent of each eye. RESULTS: The change in spherical aberration was highly correlated with the change in negative power of the contact lens at an optical zone of 4 and 6 mm (Pearson correlation coefficient=0.914 and 0.743, respectively, P<0.0001). Total HOAs had a weaker but important correlation at an optical zone of 6 mm (Pearson correlation coefficient=0.470, P=0.037) and insignificant correlation at an optical zone of 4 mm. Coma and trefoil were poorly correlated with contact lens power in either optical zone. Compared to the control using both optical zones, the -2.00 D contact lens resulted in a significant increase in total HOAs and spherical aberration, whereas the -6.00 D lens yielded a marked decrease in spherical aberration and a mild, statistically insignificant increase in total HOAs. Both contact lens powers yielded larger ocular coma and unchanged trefoil levels. The change from induction to reduction of spherical aberration occurred at -4.00 D. CONCLUSIONS: The Focus NIGHT & DAY lens vehicle harbors positive spherical aberration and coma, independently of the lens power. The negative power of contact lenses induces negative spherical aberration, which, at large values, compensates for the lens vehicle positive spherical aberration to produce a net negative spherical aberration.

Risk factors for infectious disease in corneal transplant screening.

PURPOSE: To identify potential medical and behavioral risk factors associated with infectious disease seropositivity in potential corneal donors using an extensive questionnaire completed by the next of kin. METHODS: Retrospective review of medical history and behavioral risk assessment questionnaire and microbiology data for potential corneal donors seropositive for hepatitis B, hepatitis C, human immunodeficiency virus, human T-cell leukemia virus and syphilis as compared to controls. RESULTS: Tobacco use, cigarette smoking, chest pain and heart disease are each associated with corneal donor seropositivity (P < 0.05). Vaccination in the last twelve months is inversely associated with infectious disease (P < 0.05). Statistically significant factors associated with hepatitis C positive donors include: cigarette use, illicit drug use, chest pain, cardiac medications, kidney stones and lung disease (P < 0.05). Factors most often associated with transmission of this disease panel (such as intravenous drug use, sexual contact with prostitutes and history of blood transfusion) are often not identified by the next of kin in the questionnaire. CONCLUSIONS: While there are questionnaire identified risk factors associated with seropositivity in this study, their clinical usefulness is unclear. Many factors crucial to the elimination of potentially infectious donor tissues are not identified in the posthumous history typically completed by next of kin. These questionnaires alone do not provide exclusion criteria for elimination of potentially infectious tissues from the donor pool.

[The prevalence of and attitudes toward smoking among physicians in Azuay, Ecuador]. / Prevalencia de tabaquismo y actitud hacia ese hábito entre médicos del Azuay, Ecuador.

OBJECTIVES: To learn the prevalence of smoking among physicians in the province of Azuay, Ecuador, as well as their attitudes toward the habit. METHODS: This descriptive cross-sectional study was conducted using a survey that was based on models used in previous research. The survey consisted of 14 questions on the physicians' sociodemographic characteristics, issues related to the use of tobacco, and the physicians' attitudes toward smoking among their patients. The survey was delivered to 884 physicians and answered by 687 of them (77.7%). The results were entered into an electronic database, and multivariate analysis was carried out with the SPSS version 7.5 software package. Subgroups were compared using stratified analysis. Even though the study was descriptive, parametric statistical tests were applied with the quantitative variables, and Pearson's chi-square test was used to compare associations between discrete variables. A P level < 0.05 was considered statistically significant. RESULTS: Of the 687 physicians who responded to the survey, 8 of them did not answer all the questions and so were excluded from the sample. Of the remaining 679, 509 of them (75%) were men and 170 (25%) were women. Their average age was 43, and the prevalence of smoking for the group overall was 32.4%. The large majority of the smokers were between 36 and 55 years old. The male physician smokers smoked more cigarettes per day than did the female physician smokers (P < 0.05). Of the physician smokers, 68% of the men had been smoking for more than 10 years, but this was true for only 46% of the women. In terms of when the smokers began smoking, 47.1% of the men started when they were between 16 and 20 years old, while the single largest group of women smokers (40.5%) began when they were between 21 and 25 years old. Of the physicians who smoked, 60% of them said they did so in the workplace, and 67.6% of them said they had tried to quit smoking at some point. The physician smokers were less critical of smoking than were the physician nonsmokers, and the smokers also less frequently advised their patients to stop smoking (53.2% vs. 71.6%; P < 0.01). CONCLUSIONS: The prevalence of smoking among the physicians in the province of Azuay, Ecuador, is one of the highest among physicians in Latin America, and it is also similar to the overall rate for adults in Ecuador. These patterns make it difficult to expect a reduction in smoking in the province. There is an urgent need to implement preventive and therapeutic actions to control this scourge.