A genome-wide investigation of the worldwide invader Sargassum muticum shows high success albeit (almost) no genetic diversity

Twenty years of genetic studies of marine invaders have shown that successful invaders are often characterized by native and introduced populations displaying similar levels of genetic diversity. This pattern is presumably due to high propagule pressure and repeated introductions. The opposite pattern is reported in this study of the brown seaweed, Sargassum muticum, an emblematic species for circumglobal invasions. Albeit demonstrating polymorphism in the native range, microsatellites failed to detect any genetic variation over 1,269 individuals sampled from 46 locations over the Pacific-Atlantic introduction range. Single-nucleotide polymorphisms (SNPs) obtained from ddRAD sequencing revealed some genetic variation, but confirmed severe founder events in both the Pacific and Atlantic introduction ranges. Our study thus exemplifies the need for extreme caution in interpreting neutral genetic diversity as a proxy for invasive potential. Our results confirm a previously hypothesized transoceanic secondary introduction from NE Pacific to Europe. However, the SNP panel unexpectedly revealed two additional distinct genetic origins of introductions. Also, conversely to scenarios based on historical records, southern rather than northern NE Pacific populations could have seeded most of the European populations. Finally, the most recently introduced populations showed the lowest selfing rates, suggesting higher levels of recombination might be beneficial at the early stage of the introduction process (i.e., facilitating evolutionary novelties), whereas uniparental reproduction might be favored later in sustainably established populations (i.e., sustaining local adaptation).Agence Nationale de la Recherche - ANR-10-BTBR-04; European Regional Development Fund; Fundacao para a Ciencia e a Tecnologia - SFRH/BPD/107878/2015, UID/Multi/04326/2016, UID/Multi/04326/2019; Brittany Region;info:eu-repo/semantics/publishedVersio

Minimax Estimation of Nonregular Parameters and Discontinuity in Minimax Risk

When a parameter of interest is nondifferentiable in the probability, the existing theory of semiparametric efficient estimation is not applicable, as it does not have an influence function. Song (2014) recently developed a local asymptotic minimax estimation theory for a parameter that is a nondifferentiable transform of a regular parameter, where the nondifferentiable transform is a composite map of a continuous piecewise linear map with a single kink point and a translation-scale equivariant map. The contribution of this paper is two fold. First, this paper extends the local asymptotic minimax theory to nondifferentiable transforms that are a composite map of a Lipschitz continuous map having a finite set of nondifferentiability points and a translation-scale equivariant map. Second, this paper investigates the discontinuity of the local asymptotic minimax risk in the true probability and shows that the proposed estimator remains to be optimal even when the risk is locally robustified not only over the scores at the true probability, but also over the true probability itself. However, the local robustification does not resolve the issue of discontinuity in the local asymptotic minimax risk

Nature of Bonding in Bimetallic or Ligated Aluminum Clusters

In this study, Amsterdam Density Functional software is used to model bimetallic and ligated aluminum clusters. The stability of the bimetallic clusters is well described by the Jellium model, and the nature of bonding between dopants and aluminum in the bimetallic clusters is analyzed using different criteria. We find that sodium tends to bind ionically, while the bonding of magnesium is not so obvious. We also determine that examining the Mulliken population is the most useful parameter in differentiating bonding character. Calculations on ligated aluminum clusters reveal it behaves fundamentally different than the bimetallic clusters studied in the first part. The ligated clusters contained a high HOMO-LUMO gap regardless of size and the aluminum showed a high 3p Mulliken population. These results show ligated aluminum clusters behave according to Wade-Mingos counting rules

Variation Within the Species \u3cem\u3eMacroptilium atropurpureum\u3c/em\u3e Regarding Adaptation to Grazing

The twining legume Macroptilium atropurpureum cv. Siratro was released around 1960 (Hutton 1962) and the rust resistant cultivar Aztec was released in 1994 (Bray & Woodroffe 1995). The species showed great potential for pastures in northern Australia and was planted over some 220 Kha in the 1960\u27s and 70\u27s. The species was high yielding and readily eaten by cattle. However, by the early 1980\u27s the species had declined dramatically in grazed pastures. Clements (1989) showed that a major problem with Siratro was the frequency of removal of growing points. This leads to less regrowth after grazing, less seed set and hence less regenerative capacity. Accessions with greater branching characteristics may overcome this problem

Poverty and Self-Sufficiency in the Nine-County Greater Rochester Area

Poverty and Self-Sufficiency in the Nine-County Greater Rochester Area updates data from a 2013 report. Overall, it shows that poverty is rising across the region, from 13.2 percent to 14.3 percent, based on the latest available Census figures. This report aims to update key elements from both previous studies, includingpoverty data for all the counties, towns and villages in the region, relying primarily on the latest U.S. Census data, highlight the financial stress that exists in our community by differentiating between poverty and self-sufficiency; and chronicle and summarize efforts of the greater Rochester community to understand and act upon crisis

Linkage mapping of the gpdA gene of Aspergillus nidulans

In the last few years many genes of several Aspergillus species have been cloned and sequenced. For many of these genes mutant alleles and genetic linkage data are also available. However, for those genes for which no mutant alleles have been isolated, genetic mapping was not possible. Here we report linkage mapping of the glyceraldehyde-3- phosphate dehydrogenase gene (gpdA) of A. nidulans for which no mutant alleles have been isolated. The method used is applicable to all other cloned genes