Leaf water δ18O reflects water vapour exchange and uptake by C3 and CAM epiphytic bromeliads in Panama

The distributions of CAM and C3 epiphytic bromeliads across an altitudinal gradient in western Panama were identified from carbon isotope (δ13C) signals, and epiphyte water balance was investigated via oxygen isotopes (δ18O) across wet and dry seasons. There were significant seasonal differences in leaf water (δ18Olw), precipitation, stored 'tank' water and water vapour. Values of δ18Olw were evaporatively enriched at low altitude in the dry season for the C3 epiphytes, associated with low relative humidity (RH) during the day. Crassulacean acid metabolism (CAM) δ18Olw values were relatively depleted, consistent with water vapour uptake during gas exchange under high RH at night. At high altitude, cloudforest locations, C3 δ18Olw also reflected water vapour uptake by day. A mesocosm experiment with Tillandsia fasciculata (CAM) and Werauhia sanguinolenta (C3) was combined with simulations using a non-steady-state oxygen isotope leaf water model. For both C3 and CAM bromeliads, δ18Olw became progressively depleted under saturating water vapour by day and night, although evaporative enrichment was restored in the C3 W. sanguinolenta under low humidity by day. Source water in the overlapping leaf base 'tank' was also modified by evaporative δ18O exchanges. The results demonstrate how stable isotopes in leaf water provide insights for atmospheric water vapour exchanges for both C3 and CAM systems

Direct measurements of the effects of salt and surfactant on interaction forces between colloidal particles at water-oil interfaces

The forces between colloidal particles at a decane-water interface, in the presence of low concentrations of a monovalent salt (NaCl) and of the surfactant sodium dodecylsulfate (SDS) in the aqueous subphase, have been studied using laser tweezers. In the absence of electrolyte and surfactant, particle interactions exhibit a long-range repulsion, yet the variation of the interaction for different particle pairs is found to be considerable. Averaging over several particle pairs was hence found to be necessary to obtain reliable assessment of the effects of salt and surfactant. It has previously been suggested that the repulsion is consistent with electrostatic interactions between a small number of dissociated charges in the oil phase, leading to a decay with distance to the power -4 and an absence of any effect of electrolyte concentration. However, the present work demonstrates that increasing the electrolyte concentration does yield, on average, a reduction of the magnitude of the interaction force with electrolyte concentration. This implies that charges on the water side also contribute significantly to the electrostatic interactions. An increase in the concentration of SDS leads to a similar decrease of the interaction force. Moreover the repulsion at fixed SDS concentrations decreases over longer times. Finally, measurements of three-body interactions provide insight into the anisotropic nature of the interactions. The unique time-dependent and anisotropic interactions between particles at the oil-water interface allow tailoring of the aggregation kinetics and structure of the suspension structure.Comment: Submitted to Langmui

Ampliación de la distribución geográfica de <i>Liolaemus nazca</i> Aguilar, Ramírez, Castillo, Mendoza, Vargas & Sites Jr., 2019 (Iguania: Liolaemidae) para el extremo sur de Ica y norte de Arequipa, Perú : Hábitats y conservación

In the present investigation we broaden the geographical distribution of the endemic saurian of the Peruvian desert Liolaemus nazca. Its distribution is extended in approximately 45 km from its type locality (Lomas of the San Fernando National Reserve), reporting it for the first time for the department of Arequipa. Also, its distribution of occurrence is widened to other undocumented localities in San Juan de Marcona (Nasca, Ica) and Lomas (Caravelí, Arequipa) in Peru. These new records, added to those already known, allow us to characterize their habitats and analyze their state of conservation. These data highlight the importance and ecological value of the ‘lomas’ of Marcona, a site of interest in the conservation and protection of the biodiversity it refuge.Asociación Herpetológica Argentin

Ampliación de la distribución geográfica y estado de conservación de Ctenoblepharys adspersa (Tschudi, 1845)

We extend the geographical distribution of Ctenoblepharys adspersa (Liolaemidae) an endemic and threatened lizard species from the Peruvian desert. Our new record extends the known species distribution ca. 60 km (straight line) east-southeastern from the eastemost record at Paracas National Reserve. We recorded two new type of habitat for C. adspersa that reach to the Pacific foothills and identified the native plants associated to its habitats. Moreover, we review the conservation status and the challenges that facing it, highlighted that most of its populations are vulnerable to the impacts on their habitat caused by the development of urban and agricultural infrastructure.Ampliamos la distribución geográfica de Ctenoblepharys adspersa (Liolaemidae), una especie de saurio endémico y amenazado del desierto peruano. Nuestro nuevo registro extiende la distribucion de esta especie en 60 km (línea recta) de la localidad más oriental previamente conocida, la Reserva Nacional de Paracas. Registramos dos tipos de hábitat nuevos para C. adspersa al interior de las estribaciones andinas e identificamos las plantas nativas asociadas a sus hábitats. Además, revisamos el estado de conservación de esta especie y los desafíos que implican su conservación, resaltando que la mayoría de las poblaciones son vulnerables a los impactos en su hábitat producto del desarrollo de infraestructura urbana y/o agrícol

Genome-wide association studies for methane production in dairy cattle

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Genomic selection has been proposed for the mitigation of methane (CH4) emissions by cattle because there is considerable variability in CH4 emissions between individuals fed on the same diet. The genome-wide association study (GWAS) represents an important tool for the detection of candidate genes, haplotypes or single nucleotide polymorphisms (SNP) markers related to characteristics of economic interest. The present study included information for 280 cows in three dairy production systems in Mexico: 1) Dual Purpose (n = 100), 2) Specialized Tropical Dairy (n = 76), 3) Familiar Production System (n = 104). Concentrations of CH4 in a breath of individual cows at the time of milking (MEIm) were estimated through a system of infrared sensors. After quality control analyses, 21,958 SNPs were included. Associations of markers were made using a linear regression model, corrected with principal component analyses. In total, 46 SNPs were identified as significant for CH4 production. Several SNPs associated with CH4 production were found at regions previously described for quantitative trait loci of composition characteristics of meat, milk fatty acids and characteristics related to feed intake. It was concluded that the SNPs identified could be used in genomic selection programs in developing countries and combined with other datasets for global selection

Open science, communal culture, and women’s participation in the movement to improve science

Science is undergoing rapid change with the movement to improve science focused largely on reproducibility/replicability and open science practices. This moment of change—in which science turns inward to examine its methods and practices—provides an opportunity to address its historic lack of diversity and noninclusive culture. Through network modeling and semantic analysis, we provide an initial exploration of the structure, cultural frames, and women’s participation in the open science and reproducibility literatures (n = 2,926 articles and conference proceedings). Network analyses suggest that the open science and reproducibility literatures are emerging relatively independently of each other, sharing few common papers or authors. We next examine whether the literatures differentially incorporate collaborative, prosocial ideals that are known to engage members of underrepresented groups more than independent, winner-takes-all approaches. We find that open science has a more connected, collaborative structure than does reproducibility. Semantic analyses of paper abstracts reveal that these literatures have adopted different cultural frames: open science includes more explicitly communal and prosocial language than does reproducibility. Finally, consistent with literature suggesting the diversity benefits of communal and prosocial purposes, we find that women publish more frequently in high-status author positions (first or last) within open science (vs. reproducibility). Furthermore, this finding is further patterned by team size and time. Women are more represented in larger teams within reproducibility, and women’s participation is increasing in open science over time and decreasing in reproducibility. We conclude with actionable suggestions for cultivating a more prosocial and diverse culture of science

Self-reported glaucoma prevalence and related factors, contribution to reported visual impairment, and functional burden in a cross-sectional study in Colombia

Objetivo Describir la prevalencia autorreportada de glaucoma en adultos mayores colombianos, enfatizando los factores de riesgo más importantes y las alteraciones funcionales de la vida diaria asociadas. Métodos Este es un análisis secundario de la encuesta de Salud, Bienestar y Envejecimiento realizada en el año 2015. El diagnóstico de glaucoma se obtuvo del autoinforme. Las variables funcionales se evaluaron mediante cuestionarios de actividades de la vida diaria. Se realizó un análisis descriptivo seguido de modelos de regresión bivariados y multivariados ajustando por variables de confusión. Resultados La prevalencia autoinformada de glaucoma fue de 5,67%, con mayor tasa en mujeres, OR 1,22 (1,13–1,40) p = ,003, mayor edad OR 1,02 (1,01–1,02) p < ,001, y con educación superior OR 1,38 (1,28 –1.50) p < .001. El glaucoma se asoció de forma independiente con diabetes OR 1,37 (1,18–1,61) p  < ,001 e hipertensión 1,26 (1,08–1,46) p = ,003. También mostró correlaciones estadísticamente significativas con mala SSR OR 1.15 (1.02–1.32) p < .001, discapacidad visual autoinformada 1.73 (1.50–2.01) p < .001 y deterioro en el manejo del dinero OR 1.59 (1.16–2.08) p = .002, compras de comestibles OR 1.57 (1.26–1.96) p < .001 y preparación de comidas OR 1.31 (1.06–1.63) p  = .013 y haber tenido caídas en el último año OR 1.14 (1.01–1.31) p = 0.041. Conclusión Nuestros hallazgos sugieren que la prevalencia autoinformada de glaucoma en adultos mayores en Colombia es más alta que los datos informados. El glaucoma y la discapacidad visual en adultos mayores representan un problema de salud pública, ya que el glaucoma se asoció con resultados adversos como pérdida funcional y riesgo de caídas, afectando la calidad de vida y su participación en la sociedad.Q2Q2Purpose Describe the self-reported prevalence of glaucoma in Colombian older adults, emphasizing the most important risk factors and associated daily-life functional alterations. Methods This a secondary analysis of the Health, Wellness, and Aging survey conducted in the year 2015. Diagnosis of glaucoma was obtained from self-report. Functional variables were assessed through activities of daily living questionnaires. A descriptive analysis followed by bivariate and multivariate regression models adjusting for confounding variables was conducted. Results Self-reported prevalence of glaucoma was 5.67%, with higher rate in women, OR 1.22 (1.13–1.40) p = .003, older age OR 1.02 (1.01–1.02) p < .001, and with higher education OR 1.38 (1.28–1.50) p < .001. Glaucoma was independently associated with diabetes OR 1.37 (1.18–1.61) p  < .001 and hypertension 1.26 (1.08–1.46) p = .003. It also showed statistically significant correlations with poor SRH OR 1.15 (1.02–1.32) p < .001, self-reported visual impairment 1.73 (1.50–2.01) p < .001, and impairment in money management OR 1.59 (1.16–2.08) p  = .002, grocery shopping OR 1.57 (1.26–1.96) p < .001 and preparing meals OR 1.31 (1.06–1.63) p  = .013 and having had falls during the last year OR 1.14 (1.01–1.31) p = 0.041. Conclusion Our findings suggest the self-reported prevalence of glaucoma in older adults in Colombia to be higher than reported data. Glaucoma and visual impairment in older adults represent a public health concern, since glaucoma was associated with adverse outcomes like functional loss and risk of falling, affecting the quality of life and their participation in society.https://orcid.org/0000-0001-5680-7880https://scholar.google.com/citations?view_op=search_authors&mauthors=carlos+alberto+cano-gutierrez&hl=es&oi=aohttps://scienti.minciencias.gov.co/cvlac/visualizador/generarCurriculoCv.do?cod_rh=0000054895Revista Internacional - IndexadaS