306 research outputs found
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A comparative study of sperm and egg donors' personal descriptions and goodwill messages
Research question: What information do sperm donors and egg donors include in their personal descriptions and goodwill messages?
Design: A total of 131 (76 egg, 55 sperm) donor information forms from 2011 to 2021 were analysed using qualitative content analysis for personal descriptions and goodwill messages written to recipients of donor gametes. Categorical data were analysed statistically to examine differences between egg and sperm donors.
Results: Egg donors wrote longer goodwill messages than sperm donors (X2 (1) = 6.18, P = 0.013), although they were less likely to provide a personal description (X2(1) = 4.53, P = 0.033). Sperm donors were more likely than egg donors to describe themselves through their athleticism (X2 (1) = 12.10, P < 0.001) and their personality traits (X2 (1) = 5.29, P = 0.021), such as being laid back or goal driven. Both sperm donors and egg donors included messages that wished the family and the child well, with sperm donors more likely than egg donors to include advice in their goodwill message (X2 (1) = 6.39, P = 0.012). Egg donors were more likely than sperm donors to mention motivations that involved helping others (X2 (1) = 4.59, P = 0.032).
Conclusion: Given the differences found between the content of egg and sperm donor information forms, there is a need for better information and support to be provided to gamete donors to improve the amount of information provided and ensure consistency. More specific and guided questions on the forms may help donors complete them
Spatial modeling for low pathogenicity avian influenza virus at the interface of wild birds and backyard poultry
Low pathogenicity avian influenza virus (LPAIV) is endemic in wild birds and poultry in Argentina, and active surveillance has been in place to prevent any eventual virus mutation into a highly pathogenic avian influenza virus (HPAIV), which is exotic in this country. Risk mapping can contribute effectively to disease surveillance and control systems, but it has proven a very challenging task in the absence of disease data. We used a combination of expert opinion elicitation, multicriteria decision analysis (MCDA), and ecological niche modeling (ENM) to identify the most suitable areas for the occurrence of LPAIV at the interface between backyard domestic poultry and wild birds in Argentina. This was achieved by calculating a spatially‐explicit risk index. As evidenced by the validation and sensitivity analyses, our model was successful in identifying high‐risk areas for LPAIV occurrence. Also, we show that the risk for virus occurrence is significantly higher in areas closer to commercial poultry farms. Although the active surveillance systems have been successful in detecting LPAIV‐positive backyard farms and wild birds in Argentina, our predictions suggest that surveillance efforts in those compartments could be improved by including high‐risk areas identified by our model. Our research provides a tool to guide surveillance activities in the future, and presents a mixed methodological approach which could be implemented in areas where the disease is exotic or rare and a knowledge‐driven modeling method is necessary
Diverged subpopulations in tropical Urochloa (Brachiaria) forage species indicate a role for facultative apomixis and varying ploidy in their population structure and evolution
Abstract
Background
Urochloa (syn. Brachiaria) is a genus of tropical grasses sown as forage feedstock, particularly in marginal soils. Here we aimed to clarify the genetic diversity and population structure in Urochloa species to understand better how population evolution relates to ploidy level and occurrence of apomictic reproduction.
Methods
We explored the genetic diversity of 111 accessions from the five Urochloa species used to develop commercial cultivars. These accessions were conserved from wild materials collected at their centre of origin in Africa, and they tentatively represent the complete Urochloa gene pool used in breeding programmes. We used RNA-sequencing to generate 1.1 million single nucleotide polymorphism loci. We employed genetic admixture, principal component and phylogenetic analyses to define subpopulations.
Results
We observed three highly differentiated subpopulations in U. brizantha, which were unrelated to ploidy: one intermixed with U. decumbens, and two diverged from the former and the other species in the complex. We also observed two subpopulations in U. humidicola, unrelated to ploidy; one subpopulation had fewer accessions but included the only characterized sexual accession in the species. Our results also supported a division of U. decumbens between diploids and polyploids, and no subpopulations within U. ruziziensis and U. maxima.
Conclusions
Polyploid U. decumbens are more closely related to polyploid U. brizantha than to diploid U. decumbens, which supports the divergence of both polyploid groups from a common tetraploid ancestor and provides evidence for the hybridization barrier of ploidy. The three differentiated subpopulations of apomictic polyploid U. brizantha accessions constitute diverged ecotypes, which can probably be utilized in hybrid breeding. Subpopulations were not observed in non-apomictic U. ruziziensis. Sexual Urochloa polyploids were not found (U. brizantha, U. decumbens) or were limited to small subpopulations (U. humidicola). The subpopulation structure observed in the Urochloa sexual–apomictic multiploidy complexes supports geographical parthenogenesis, where the polyploid genotypes exploit the evolutionary advantage of apomixis, i.e. uniparental reproduction and clonality, to occupy extensive geographical areas
Complex polyploid and hybrid species in an apomictic and sexual tropical forage grass group: genomic composition and evolution in Urochloa (Brachiaria) species
Background and Aims
Diploid and polyploid Urochloa (including Brachiaria, Panicum and Megathyrsus species) C-4 tropical forage grasses originating from Africa are important for food security and the environment, often being planted in marginal lands worldwide. We aimed to characterize the nature of their genomes, the repetitive DNA and the genome composition of polyploids, leading to a model of the evolutionary pathways within the group including many apomictic species.
Methods
Some 362 forage grass accessions from international germplasm collections were studied, and ploidy was determined using an optimized flow cytometry method. Whole-genome survey sequencing and molecular cytogenetic analysis were used to identify chromosomes and genomes in Urochloa accessions belonging to the 'brizantha' and 'humidicola' agamic complexes and U. maxima.
Key Results
Genome structures are complex and variable, with multiple ploidies and genome compositions within the species, and no clear geographical patterns. Sequence analysis of nine diploid and polyploid accessions enabled identification of abundant genome-specific repetitive DNA motifs. In situ hybridization with a combination of repetitive DNA and genomic DNA probes identified evolutionary divergence and allowed us to discriminate the different genomes present in polyploids.
Conclusions
We suggest a new coherent nomenclature for the genomes present. We develop a model of evolution at the whole-genome level in diploid and polyploid accessions showing processes of grass evolution. We support the retention of narrow species concepts for Urochloa brizantha, U. decumbens and U. ruziziensis, and do not consider diploids and polyploids of single species as cytotypes. The results and model will be valuable in making rational choices of parents for new hybrids, assist in use of the germplasm for breeding and selection of Urochloa with improved sustainability and agronomic potential, and assist in measuring and conserving biodiversity in grasslands
Determinación por AFLP de la estabilidad genética de plantas de yuca obtenidas por embriogenesis somática y organogenesis
AFLP techniques have been reported to determine the genetic stability at a molecular level of cassava plants propagated by several methods: somatic embryogenesis, organogenesis and field conditions. ‘CMC-76’, ‘CEMSA 74-725’ and ‘Señorita’ clones from the germplasm collection kept at the INIVIT were used. Two Kit for AFLPs were applied, one of them combined selection primers +2/+3 (AFLP Analysis System II GibcoBRL) and the other +3/+3 (AFLP® Analysis System I, GibcoBRL®). 44 combination primers (EcoRI + 2 ó EcoRI + 3) were tested and five were selected as the most efficient. Plants derived from different propagation methods within each clone resulted identical genetically and differences were only observed in the three studied clones. This result corroborates the efficiency of AFLPs to study the genetic stability of micropropagated material, storaged at medium term or in cryoconservation. Besides, plants obtained with these techniques can be used for the production of high quality planting material in this crop.Key word: genetic stability, organogenesis, somatic embryogenesisSe describe el empleo de la técnica de AFLP para determinar a nivel molecular la estabilidad genética de las plantas de yuca (Manihot esculenta, Crantz) propagadas por diferentes métodos: embriogénesis somática, organogénesis y tradicional en campo. Se utilizaron los clones CMC-76, CEMSA 74-725 y Señorita del banco de germoplasma del INIVIT. Se aplicaron dos Kit para AFLP, uno con una combinación de cebadores de selección +2/+3 (AFLP® Analysis System II, GibcoBRL®) y otro +3/+3 (AFLP® Analysis System I, GibcoBRL®). Se estudiaron 44 combinaciones de cebadores (EcoRI+2 ó EcoRI+3 x MseI+3) y se seleccionaron cinco como los más eficientes. Se encontró que las plantas procedentes de los diferentes métodos de propagación estudiados dentro de cada clon, resultaron genéticamente idénticas y sólo fueron observadas diferencias entre los tres clones estudiados. Este resultado confirmó la utilidad de los AFLP para el estudio de la estabilidad genética de los materiales micropropagados, conservados a mediano plazo o crioconservados. Además, las plantas obtenidas por estas técnicas pueden ser utilizadas para la producción de material de plantación de alta calidad en este cultivo.Palabras clave: embriogénesis somática, estabilidad genética, Manihot esculenta, organogénesi
Defining the structure and stability of macromolecular assemblies in solution: the re-emergence of analytical ultracentrifugation as a practical tool
Hospitalization and mortality following non-attendance for hemodialysis according to dialysis day of the week : a European cohort study
Background
The extension of the interdialytic interval due to due to dialysis session non-attendance varies according to which session of the week the patient misses. The impact of this on subsequent hospitalization and mortality is unknown.
Methods
The ARO cohort study prospectively collected data from hemodialysis patients across 15 European countries on demography, comorbidity, laboratory, hospitalisation, mortality and individual hemodialysis sessions from 2007 to 2014. Event rates for death and hospitalisation according to dialysis day of the week were calculated for patients who attended the three previous scheduled hemodialysis sessions, who then on the next scheduled dialysis day either attended or did not attend. The hazard ratio for these events following non-attendance for the first compared to the second dialysis session of the week was estimated using Cox proportional hazards model adjusted for patient demographics.
Results
3.8 million hemodialysis sessions in 9397 patients were analysed. The non-attendance rates for Monday/Wednesday/Friday sessions were 0.8, 0.9% & 1.4% respectively, and for Tuesday/Thursday/Saturday sessions were 0.6, 1.0% & 1.2% respectively. Compared to those who attended, for the 48–72 h between non-attendance and the next scheduled haemodialysis session, mortality significantly increased from 4.86 to 51.9/100 pt-yrs and hospitalisation increased from 0.58 to 2.1/yr. As time from the two-day break increased, the risk associated with non-attendance lessened: compared to missing the second hemodialysis session, missing the first session had a hazard ratio for mortality of 2.04 (95% CI 1.27–3.29), and for hospitalisation 1.78 (95% CI 1.29–2.47). In patients who attended their scheduled dialysis session and the three preceding, after the two-day break there were absolute increases in mortality (8.3 vs. 4.9/100 pt-yrs) and hospitalisation (1.0 vs. 0.6/yr for the rest of the week) comparable to previous studies.
Conclusions
In addition to hospitalisation and mortality increases seen after the two-day break, additional harm may be manifested in the greater increases in mortality and hospitalisation observed after non-attendance for the first hemodialysis session after the two-day break compared to missing other sessions
A global surveillance system for crop diseases
To satisfy a growing demand for food, global agricultural production must increase by 70% by 2050. However, pests and crop diseases put global food supplies at risk. Worldwide, yield losses caused by pests and diseases are estimated to average 21.5% in wheat, 30.0% in rice, 22.6% in maize, 17.2% in potato, and 21.4% in soybean (1); these crops account for half of the global human calorie intake (2). Climate change and global trade drive the distribution, host range, and impact of plant diseases (3), many of which can spread or reemerge after having been under control (4). Though many national and regional plant protection organizations (NPPOs and RPPOs) work to monitor and contain crop disease outbreaks, many countries, particularly low-income countries (LICs), do not efficiently exchange information, delaying coordinated responses to prevent disease establishment and spread. To improve responses to unexpected crop disease spread, we propose a Global Surveillance System (GSS) that will extend and adapt established biosecurity practices and networking facilities into LICs, enabling countries and regions to quickly respond to emerging disease outbreaks to stabilize food supplies, enhancing global food protection
Manihot-EcoMap - Distribución ecogeográfica del género Manihot en Colombia - Implicaciones para la conservación y flujo de genes entre cultivo silvestres
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