Defined arrays of transition metal ions embedded in tailored polydentate ligand scaffolds allow for a systematic design of their physical properties. Such molecular strings of closed-shell transition ...metal centers are particularly interesting for Group 11 metal ions in the oxidation state +1 if they undergo metallophilic d10···d10 contact interactions since these clusters are oftentimes efficient photoluminescence (PL) emitters. Copper is particularly attractive as a sustainable earth-abundant coinage metal source and because of the ability of several CuI complexes to serve as powerful thermally activated delayed fluorescence (TADF) emitters in molecular/organic light-emitting devices (OLEDs). Our combined synthetic, crystallographic, photophysical, and computational study describes a straight tetracuprous array possessing a centrally disconnected CuI 2···CuI 2 chain and a continuous helically bent CuI 4 complex. This molecular helix undergoes a facile rearrangement in diethyl ether solution, yielding an unprecedented nanosized CuI 10 cluster (2.9 × 2.0 nm) upon crystallization. All three clusters show either bright blue phosphorescence, TADF, or green/yellow multiband phosphorescence with quantum yields between 6.5 and 67%, which is persistent under hydrostatic pressure up to 30 kbar. Temperature-dependent PL investigations in combination with time-dependent density-functional theory (TD-DFT) calculations and void space analyses of the crystal packings complement a comprehensive correlation between the molecular structures and photoluminescence properties.
Abstract Background Downy mildew is the most relevant disease of quinoa and the most widespread. Though, little is known about the genetics of resistance to this disease. The objective of this study ...was to identify the genomic regions controlling downy mildew resistance in quinoa and candidate genes for this trait. With this aim we carried out a GWAS analysis in a collection formed by 211 quinoa accessions from different origins. This approach was combined with inheritance studies and Bulk Segregant Analysis (BSA) in a segregating population. Results GWAS analysis identified 26 genomic regions associated with the trait. Inheritance studies in a F 2 population segregating for resistance revealed the existence of a major single dominant gene controlling downy mildew complete resistance in quinoa accession PI614911. Through BSA, this gene was found to be located in chromosome 4, in a region also identified by GWAS. Furthermore, several plant receptors and resistance genes were found to be located into the genomic regions identified by GWAS and are postulated as candidate genes for resistance. Conclusions Until now, little was known about the genetic control of downy mildew resistance in quinoa. A previous inheritance study suggested that resistance to this disease was a quantitative polygenic trait and previous GWAS analyses were unable to identify accurate markers for this disease. In our study we demonstrate the existence of, at least, one major gene conferring resistance to this disease, identify the genomic regions involved in the trait and provide plausible candidate genes involved in defense. Therefore, this study significantly increases our knowledge about the genetics of downy mildew resistance and provides relevant information for breeding for this important trait.
Sunflower breeding for resistance to the parasitic plant sunflower broomrape (Orobanche cumana Wallr.) requires the identification of novel resistance genes. In this research, we conducted a ...genome-wide association study (GWAS) to identify QTLs associated with broomrape resistance.
The marker-trait associations were examined across a germplasm set composed of 104 sunflower accessions. They were genotyped with a 600k AXIOM® genome-wide array and evaluated for resistance to three populations of the parasite with varying levels of virulence (races EFR, FGV, and GTK) in two environments.
The analysis of the genetic structure of the germplasm set revealed the presence of two main groups. The application of optimized treatments based on the general linear model (GLM) and the mixed linear model (MLM) allowed the detection of 14 SNP markers significantly associated with broomrape resistance. The highest number of marker-trait associations were identified on chromosome 3, clustered in two different genomic regions of this chromosome. Other associations were identified on chromosomes 5, 10, 13, and 16. Candidate genes for the main genomic regions associated with broomrape resistance were studied and discussed. Particularly, two significant SNPs on chromosome 3 associated with races EFR and FGV were found at two tightly linked SWEET sugar transporter genes. The results of this study have confirmed the role of some QTL on resistance to sunflower broomrape and have revealed new ones that may play an important role in the development of durable resistance to this parasitic weed in sunflower.
Sunflower broomrape (
Wallr.) is a holoparasitic plant that causes major yield losses to sunflower crops in the Old World. Efforts to understand how this parasitic weed recognizes and interacts with ...sunflowers are important for developing long-term genetic resistance strategies. However, such studies are hampered by the lack of genetic tools for
. The objectives of this research were to construct a genetic linkage map of this species using SSR and SNP markers, and mapping the
locus that is involved in plant pigmentation. The genetic map was developed from the progenies of a cross between the
inbred lines EK-12 and EK-A1, which originated from populations belonging to two distant and geographically separated gene pools identified in Spain. The inbred lines also differed in plant pigmentation, with EK-A1 lacking anthocyanin pigmentation (
genotype). A genetic map comprising 26 SSR and 701 SNP markers was constructed, which displayed 19 linkage groups (LGs), corresponding to the 19 chromosome pairs of
. The total length of the map was 1795.7 cM, with an average distance between two adjacent positions of 2.5 cM and a maximum map distance of 41.9 cM. The
locus mapped to LG19 between the SNP markers OS02468 and OS01653 at 7.5 and 3.4 cM, respectively. This study constitutes the first linkage map and trait mapping study in
spp., laying a key foundation for further genome characterization and providing a basis for mapping additional traits such as those having a key role in parasitism.
Introducción: Los médicos especialistas tienen un alto grado de preparación académica en su formación. Sin embargo, su producción científica no corresponde con su grado de preparación. Objetivo: ...Determinar la frecuencia de publicaciones científicas encontradas en Google Académico y Scopus de los médicos especialistas peruanos. Metodología: Estudio transversal analítico donde se hizo un muestreo aleatorio de los especialistas médicos registrados en el Colegio Médico del Perú durante el año 2017. A los seleccionados se los clasificó según si habían publicado en revistas que podían ser encontradas por el buscador Google Académico o que estuviesen indexadas a Scopus. Se reportó las cantidades totales de publicaciones y sus asociaciones estadísticas. Resultados: De los 2108 especialistas, 1810 (85,9 %) y 2027 (96,2 %) nunca han publicado en revistas científicas que pueda ser encontradas por Google Académico o indizadas a Scopus, respectivamente. Las especialidades que más resultados tuvieron en Google Académico fueron gastroenterología (46,3 %), dermatología (44,4 %) y neurología (42,5 %); en cambio, en Scopus fue neurología (15,0 %), gastroenterología y dermatología (ambas con 11,1 %), así como, patología (10,9 %). Lo máximo que un autor tuvo en revistas extranjeras de Scopus fue 4 artículos originales como corresponsal. Hubo asociaciones estadísticamente significativas según la menor cantidad de publicaciones de Scopus que tuvieron quince especialidades (todos los valores p<0,042), de las cuales, trece no tuvieron publicación alguna. Conclusiones: Los médicos especialistas no tienen una abundante producción científica. De manera que, es importante incentivar el desarrollo científico de los especialistas
Downy mildew, caused by Peronospora variabilis, is the most important quinoa disease worldwide. However, little is known about the resistance mechanisms acting against this disease. The study goals ...were to identify quinoa accessions showing resistance to P. variabilis under Spanish field conditions and to characterize the resistance mechanism involved. Towards these objectives, a total amount of 229 accessions of Chenopodium quinoa and one accession of each of the species Chenopodiun berlandieri subs. nutillae, Chenopodium ugandae, and Chenopodium opulifolium were screened for resistance to P. variabilis under field conditions in Córdoba, Spain, during two seasons. The response to P. variabilis in the accessions showed a continuous distribution ranging from complete resistance to high susceptibility. Fifteen resistant and one susceptible accessions were selected for further histological studies. Histological results showed that resistance to downy mildew in quinoa acts mainly at the stage of colony establishment. In resistant accessions, no colonies were formed or success in colony establishment was significantly reduced compared with the susceptible control. Hypersensitive response was associated with colony abortion in a number of the resistant accessions. This work is the first proof of hypersensitive reaction occurrence in quinoa as a response to P. variabilis.
Wildlife-vehicle collisions are a serious conservation issue. In Argentina, wildlife road kill represents a threat to numerous species, especially around protected areas. With the aim of analyzing a ...possible seasonal and spatial patterns of mammalian death due to road kill, I sampled 97 km of the RP No. 17 in the south of multiple-use natural protected area 'Bañados del Río Dulce y Laguna Mar Chiquita' in Cordoba Province, Argentina. I analyzed the frequencies and density of road kill in winter 2015, spring 2015, and summer 2015/2016. The Kilometric Index of Abundance was used to identify the road stretches with elevated road kill. I recorded a total of 190 individuals representing 13 species. Of the mammalian species that inhabit the study area, more than 80% were affected by vehicle collisions. Three critical road stretches were identified. Mammalian mortality suggests a reduction of 42.36% between winter and spring. Lycalopex gymnocercus was the species with a statistically significant reduction (Mann-Whitney U, p = <0.03) in its road kill. Seasonal differences in mammalian mortality were likely due to seasonally variable behavior, abundances, and reproductive activity. This study provides to wildlife managers an opportunity to direct mitigation measures to reduce mammalian road kill.
Abstract
Between 1940 and 1970, more than 4 million African Americans moved from the South to the North of the US, during the Second Great Migration. This same period witnessed the struggle and ...eventual success of the civil rights movement in ending institutionalized racial discrimination. This article shows that the Great Migration and support for civil rights are causally linked. Predicting Black inflows with a shift-share instrument, we find that the Great Migration raised support for the Democratic Party, increased Congress members’ propensity to promote civil rights legislation, and encouraged pro-civil rights activism outside the US South. We provide different pieces of evidence that support for civil rights was not confined to the Black electorate but was also shared by segments of the white population.
The North American beaver Castor canadensis is an invasive species in the Tierra del Fuego Archipelago. Due to this biological invasion, Argentina and Chile signed an agreement to restore affected ...ecosystems by eradicating beavers. In southern Patagonia, the beavers’ ecological impacts are well studied, but there is a relative lack of information on how their invasion (and potential removal) could affect bird communities.
In the southern portion of Tierra del Fuego's ‘big island’ (Isla Grande), we conducted passive acoustic monitoring and avian point counts in intact riparian forests, beaver ponds and beaver meadows (i.e. drained ponds) to assess spatial and seasonal differences in acoustic activity and avian abundance, species diversity and functional diversity.
During spring and summer, acoustic activity was significantly higher in meadows than in forests, with ponds exhibiting intermediate values.
Abundance and species diversity exhibited similar patterns, driven largely by resident passerines, while functional diversity tended to be highest in ponds, largely due to ducks and raptors. Effects were weaker in fall and winter.
Acoustic metrics exhibited moderate to strong correlations with all point‐count‐derived metrics.
Synthesis and applications. At the patch level, the avian community was more abundant and diverse in beaver‐modified habitats than in intact riparian forests, though communities in modified patches may not differ substantially from those in analogous natural open and wetland habitats. Dam breaching and pond drainage did not yield a return to an intact forest bird community, indicating that active reforestation may be necessary to restore avian communities to pre‐beaver conditions in the short to medium term, as sought by the binational agreement. Given the immense challenges of eradication and restoration, its social‐ecological costs and benefits—including those related to avifauna—should be thoroughly considered in establishing goals or indicators of success.
Resumen
El castor norteamericano Castor canadensis es una especie invasora en el Archipiélago de Tierra del Fuego. Debido a esta invasión biológica, Argentina y Chile firmaron un acuerdo para restaurar los ambientes afectados por medio de la erradicación. Los impactos ecológicos del castor en el sur de la Patagonia son bien estudiados, pero existe una relativa falta de información sobre cómo su invasión (y potencial remoción) podría afectar a las comunidades de aves.
En la parte sur de la Isla Grande de Tierra del Fuego, llevamos a cabo un monitoreo acústico pasivo y conteos por puntos de aves en bosques ribereños intactos, embalses de castor y praderas de castor (embalses drenados) para evaluar las diferencias espaciales y estacionales de la actividad acústica, la abundancia y diversidad de aves así como su diversidad funcional.
Durante la primavera y el verano, la actividad acústica fue significativamente mayor en las praderas que en los bosques, y los embalses mostraron valores intermedios.
La abundancia y la diversidad de especies exhibieron patrones similares, impulsados principalmente por paseriformes residentes, aunque la diversidad funcional tendió a ser mayor en los embalses, en gran parte debido a los patos y aves rapaces. Los efectos fueron más débiles en otoño e invierno.
Las métricas acústicas mostraron correlaciones de moderadas a fuertes con todas las métricas derivadas de los conteos por puntos.
Síntesis y aplicaciones. A nivel de parche, la comunidad de aves fue más abundante y diversa en hábitats modificados por castores que en los bosques ribereños intactos, aunque las comunidades en parches modificados pueden no diferir sustancialmente de aquellas en hábitats naturales análogos abiertos y humedales. La ruptura de diques y el drenado de los embalses no produjeron un retorno a una comunidad de aves semejante a la del bosque intacto, indicando que puede ser necesaria una reforestación activa para restaurar las comunidades de aves a condiciones previas al castor en el corto y mediano plazo, como se busca por el acuerdo binacional. Dados los inmensos desafíos que implican la erradicación y restauración, sus costos y beneficios socio‐ecológicos—incluidos los relacionados con la avifauna—deberían ser considerados a fondo al establecer metas o indicadores de éxito.
At the patch level, the avian community was more abundant and diverse in beaver‐modified habitats than in intact riparian forests, though communities in modified patches may not differ substantially from those in analogous natural open and wetland habitats. Dam breaching and pond drainage did not yield a return to an intact forest bird community, indicating that active reforestation may be necessary to restore avian communities to pre‐beaver conditions in the short to medium term, as sought by the binational agreement. Given the immense challenges of eradication and restoration, its social‐ecological costs and benefits—including those related to avifauna—should be thoroughly considered in establishing goals or indicators of success.
Sterically crowded tetradentate bis(amidines) encapsulate their N–H functionalities or unveil them to undergo inter‐ and intramolecular hydrogen bonding both in solid state and solution, depending on ...a subtle interplay between the amidine backbone substituents. X‐ray crystallography reveals for four distinct ZZ(syn/syn) and EE(syn/syn) bis(amidines) that bulky terminal N‐Mes groups in combination with N2C‐tBu or N2C‐Ph substituents result in steric protection of the N–H moieties, whereas less crowded terminal p‐tBu(C6H4) groups either show encapsulation (N2C‐tBu) or hydrogen bonding (N2C‐Ph), the latter resulting in a bis(amidine) dimer formed by inter‐ and intramolecular hydrogen bonds. Moreover, a supramolecular solvent adduct consisting of one bis(amidine) and four ethanol molecules is presented. DFT calculations show that both the dimerization and formation of the solvent adduct is associated with a significant energy gain (dimerization: ΔE = –27.7 kcal/mol; formation of ethanol adduct: ΔE = –64.3 kcal/mol). The corresponding four Li bis(amidinates) are weakly blue to green‐emissive in THF solution. Overall, a new series of highly flexible bis(amidines) has been examined.
Flexible ethylene‐bridged tetradentate bis(amidines) either encapsulate their N–H moieties through steric protection or form versatile networks of hydrogen bonds both in the solid state and in solution. They also produce blue to green emissions upon deprotonation.
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