Evolutionary trends of reproductive phenotype in Cycadales: an analysis of morphological evolution in Ceratozamia.

BACKGROUND AND AIMS: The size and shape of reproductive structures is especially relevant in evolution because these characters are directly related to the capacity of pollination and seed dispersal, a process that plays a basic role in evolutionary patterns. The evolutionary trajectories of reproductive phenotypes in gymnosperms have received special attention in terms of pollination and innovations related to the emergence of the Spermatophytes. However, variability of reproductive structures, evolutionary trends and the role of environment in the evolution of cycad species have not been well documented and explored. This study considered this topic under an explicitly phylogenetic and evolutionary approach that included a broad sampling of reproductive structures in the genus Ceratozamia. METHODS: We sampled 1400 individuals of 36 Ceratozamia species to explore evolutionary pattern and identify and evaluate factors that potentially drove their evolution. We analyzed characters for both pollen and ovulate strobili within a phylogenetic framework using different methods and characters (i. e., molecular and both quantitative and qualitative morphological) to infer phylogenetic relationships. Using this phylogenetic framework, evolutionary models of trait evolution for strobilar size were evaluated. In addition, quantitative morphological variation and its relation to environmental variables across species were analyzed. KEY RESULTS: We found contrasting phylogenetic signals between characters of pollen and ovulate strobili. These structures exhibited high morphological disparity in several characters related to size. Results of analyses of evolutionary trajectories suggested a stabilizing selection model. In regards to phenotype-environment, the analysis produced mixed results and differences for groups in the vegetation type where the species occur; however, a positive relationship with climatic variables was found. CONCLUSIONS: The integrated approach synthesized reproductive phenotypic variation with current phylogenetic hypotheses and provided explicit statements of character evolution. The characters of volume for ovulate strobili were the most informative, which could provide a reference for further study of the evolutionary complexity in Ceratozamia. Finally, heterogeneous environments, which are under changing weather conditions, promote variability of reproductive structures.

Design and Backdrivability Modeling of a Portable High Torque Robotic Knee Prosthesis With Intrinsic Compliance For Agile Activities.

High-performance prostheses are crucial to enable versatile activities like walking, squatting, and running for lower extremity amputees. State-of-the-art prostheses are either not powerful enough to support demanding activities or have low compliance (low backdrivability) due to the use of high speed ratio transmission. Besides speed ratio, gearbox design is also crucial to the compliance of wearable robots, but its role is typically ignored in the design process. This paper proposed an analytical backdrive torque model that accurately estimate the backdrive torque from both motor and transmission to inform the robot design. Following this model, this paper also proposed methods for gear transmission design to improve compliance by reducing inertia of the knee prosthesis. We developed a knee prosthesis using a high torque actuator (built-in 9:1 planetary gear) with a customized 4:1 low-inertia planetary gearbox. Benchtop experiments show the backdrive torque model is accurate and proposed prosthesis can produce 200 Nm high peak torque (shield temperature <60°C), high compliance (2.6 Nm backdrive torque), and high control accuracy (2.7/8.1/1.7 Nm RMS tracking errors for 1.25 m/s walking, 2 m/s running, and 0.25 Hz squatting, that are 5.4%/4.1%/1.4% of desired peak torques). Three able-bodied subject experiments showed our prosthesis could support agile and high-demanding activities.

Spatiotemporal variation in the adult sex ratio, male aggregation, and movement of two tropical cloud forest dung beetles.

While theory suggests that at conception the sex ratio should be balanced (1:1), this can be variable across space and time in wild populations. Currently, studies of the environmental factors that regulate adult sex ratio (ASR) in species with different life history traits are scarce. Using capture-recapture over a year, we analyzed the influence of habitat type (forest and nonforest) and season (rainy and dry) on variation in ASR, male aggregation and the trajectory movement of 2 dung beetle species with different life history traits: Deltochilum mexicanum (a hornless roller species) and Dichotomius satanas (a tunneler species with horns on its head and thorax). We found opposite tendencies. The D. mexicanum population tends to be female-biased, but the population of D. satanas tends to be predominantly male, and observed values were not related to habitat type or season. However, the 95% confidence intervals estimated were highly variable between seasons depending on habitat. On examining the monthly variation in ASR for both habitats, we found that it depends on the species. In addition, male aggregation differed between species depending on habitat type and season, and species movement patterns were closely related to their habitat preferences. Based on our results, we argue that comparative population studies of species with different life history traits are necessary to understand the variation in demographic parameters as well as its ecological and evolutionary implications in the face of spatial and climatic environmental variation.

Histologic characterization and risk factors for persistent albuminuria in adolescents in a region of highly prevalent end-stage renal failure of unknown origin.

Background: End-stage renal failure of unknown origin (ESRD-UO) is a public health problem in Mexico and many regions of the world. The prevalence of ESRD-UO in Aguascalientes, Mexico, is one of the highest worldwide, particularly in adults between 20 and 40 years of age. Our aim was to screen adolescents for chronic kidney disease (CKD) to identify risk factors and histologically characterize adolescents with persistent albuminuria. Methods: This was a cross-sectional, observational and comparative study of adolescents in whom serum creatinine and the albumin:creatinine ratio (ACR) were determined when screening for CKD. A clinical evaluation and risk factor survey were conducted. Patients with an abnormal ACR (≥30 mg/g) or a low glomerular filtration rate (GFR) (≤75 mL/min/1.73 m2) were re-evaluated and a renal ultrasound (US) was obtained. A kidney biopsy was performed in patients with persistent albuminuria. Results: A total of 513 students were included; 19 had persistent albuminuria and 494 were controls. The prevalence of persistent albuminuria was 3.7% [95% confidence interval (CI) 2.1-5.3]. Only one patient had a decreased GFR. None of the patients with persistent albuminuria had anatomical abnormalities of the urinary tract by renal US. Patients with persistent albuminuria had a decreased total renal volume compared with the control group (150 versus 195 mL/m2; P < 0.01). Eighteen kidney biopsies were performed; 72% had glomerulomegaly and only one patient had mild fibrosis. Podocyte abnormalities were evident on electron microscopy, including partial fusion (100%), microvillous degeneration (80%) and increased organelles (60%). Risk factors for persistent albuminuria were: homestead proximity to maize crops, the use of pesticides at the father's workplace, a family history of CKD and blood pressure abnormalities. The body mass index and breastfeeding were protective factors. Conclusions: The prevalence of persistent albuminuria in adolescents in Aguascalientes is high and histologic compromise is characterized by podocyte injury in the absence of fibrosis. The renal volume of persistent albuminuria patients was decreased, suggesting oligonephronia. Exposure to environmental toxins such as pesticides, even prenatally, may be responsible for this pathological entity. Screening programs in adolescents by determining ACR are necessary in this setting.

Central blood pressure and vascular stiffness in Mexican population.

Introduction: Central blood pressure (CBP) is considered a measure of prognostic value for cardiovascular risk. In turn, the aortic pulse wave velocity (PWVAo) and augmentation index (Aix) have been related to arterial stiffness and cardiovascular risk. Controversies exist regarding the reference values in different ethnic groups, ages, and anthropometrics. The objective of this study is to evaluate the CBP and arterial stiffness parameters in a Mexican population by age, gender, and anthropometry. Methods: Between 2015 and 2016, 1009 apparently healthy subjects were recruited in the Instituto Nacional de Cardiología Ignacio Chávez. Using the Arteriograph (TensioMed) equipment with an oscillometric technique, CBP, central pulse pressure (cPP), PWVAo, and Aix were acquired. All results were automatically obtained by computer software version 3.0.0.4. Results: Female sex was prevalent (72%), mean age was 47 ± 12 years; 26% had normal weight, 43% were overweight, and 30% had obesity. The reference values were higher than those reported in other populations. PWVAo and Aix were always found to be higher in females. A central-brachial pressure gradient was observed in < 40 years with lower CBP. Body mass index (BMI) presented a direct and positive correlation with CBP (p < 0.001); however, PWVAo and Aix were not modified. Conclusion: CBP, cPP, PWVAo, and Aix parameters should be considered based on age, gender, and BMI. In Mexican population, CBP and cPP values were higher compared with other previously reported values, especially in women, the elderly, and obese. PWVAo and Aix are higher in older women; however, they are not modified by BMI.

Introducción: La presión central aórtica (PCA) se considera una medida del valor pronóstico. A su vez, la velocidad de la onda del pulso aórtico (VOPA) y el índice de aumento (IA) se han relacionado con la rigidez arterial y riesgo cardiovascular. Existen controversias sobre los valores de referencia en diferentes grupos. El objetivo de este estudio es evaluar estos parámetros en una población mexicana por edad, género y antropometría. Métodos: Entre 2015 y 2016 se reclutaron 1,009 sujetos aparentemente sanos en el Instituto Nacional de Cardiología Ignacio Chávez. Usando el equipo de Arteriograph (TensioMed) con técnica oscilométrica, se adquirieron: PCA, presión de pulso central, VOPA e IA. Todos los resultados fueron obtenidos automáticamente. Resultados: El sexo femenino fue prevalente (72%), edad de 47 ± 12 años; 26% con peso normal, 43% con sobrepeso y 30% con obesidad. Todos los valores fueron superiores a los reportados en otras poblaciones. VOPA e IA siempre fueron más altos en mujeres. Se observó un gradiente de presión central-braquial en < 40 años, con menor PCA. El IMC presentó una correlación directa y positiva con la PCA (p < 0,001), sin embargo, VOPA e IA no se modificaron. Conclusión: Los parámetros de PCA, VOPA e IA deben considerarse en función de edad, género e IMC. En una población mexicana, los valores de PCA fueron más altos en comparación con informados previamente (Europa y Asia), especialmente en mujeres, ancianos y obesos. VOPA e IA son más altos en mujeres mayores; sin embargo, no son modificados por el IMC.

Central blood pressure and vascular stiffness in Mexican population / Presión central aórtica y rigidez vascular en mexicanos

Abstract Introduction: Central blood pressure (CBP) is considered a measure of prognostic value for cardiovascular risk. In turn, the aortic pulse wave velocity (PWVAo) and augmentation index (Aix) have been related to arterial stiffness and cardiovascular risk. Controversies exist regarding the reference values in different ethnic groups, ages, and anthropometrics. The objective of this study is to evaluate the CBP and arterial stiffness parameters in a Mexican population by age, gender, and anthropometry. Methods: Between 2015 and 2016, 1009 apparently healthy subjects were recruited in the Instituto Nacional de Cardiología Ignacio Chávez. Using the Arteriograph (TensioMed) equipment with an oscillometric technique, CBP, central pulse pressure (cPP), PWVAo, and Aix were acquired. All results were automatically obtained by computer software version 3.0.0.4. Results: Female sex was prevalent (72%), mean age was 47 ± 12 years; 26% had normal weight, 43% were overweight, and 30% had obesity. The reference values were higher than those reported in other populations. PWVAo and Aix were always found to be higher in females. A central-brachial pressure gradient was observed in < 40 years with lower CBP. Body mass index (BMI) presented a direct and positive correlation with CBP (p < 0.001); however, PWVAo and Aix were not modified. Conclusion: CBP, cPP, PWVAo, and Aix parameters should be considered based on age, gender, and BMI. In Mexican population, CBP and cPP values were higher compared with other previously reported values, especially in women, the elderly, and obese. PWVAo and Aix are higher in older women; however, they are not modified by BMI.

Resumen Introducción: La presión central aórtica (PCA) se considera una medida del valor pronóstico. A su vez, la velocidad de la onda del pulso aórtico (VOPA) y el índice de aumento (IA) se han relacionado con la rigidez arterial y riesgo cardiovascular. Existen controversias sobre los valores de referencia en diferentes grupos. El objetivo de este estudio es evaluar estos parámetros en una población mexicana por edad, género y antropometría. Métodos: Entre 2015 y 2016 se reclutaron 1,009 sujetos aparentemente sanos en el Instituto Nacional de Cardiología Ignacio Chávez. Usando el equipo de Arteriograph (TensioMed) con técnica oscilométrica, se adquirieron: PCA, presión de pulso central, VOPA e IA. Todos los resultados fueron obtenidos automáticamente. Resultados: El sexo femenino fue prevalente (72%), edad de 47 ± 12 años; 26% con peso normal, 43% con sobrepeso y 30% con obesidad. Todos los valores fueron superiores a los reportados en otras poblaciones. VOPA e IA siempre fueron más altos en mujeres. Se observó un gradiente de presión central-braquial en < 40 años, con menor PCA. El IMC presentó una correlación directa y positiva con la PCA (p < 0,001), sin embargo, VOPA e IA no se modificaron. Conclusión: Los parámetros de PCA, VOPA e IA deben considerarse en función de edad, género e IMC. En una población mexicana, los valores de PCA fueron más altos en comparación con informados previamente (Europa y Asia), especialmente en mujeres, ancianos y obesos. VOPA e IA son más altos en mujeres mayores; sin embargo, no son modificados por el IMC.