Simulation of CPT penetration in sensitive clay

This paper presents the results from numerical simulations of CPTu penetration in a natural clay combining the SCLAY1S constitutive model with a large deformation Finite Element framework including a coupled deformation and porewater pressure formulation. The hierarchical model formulation of SCLAY1S captures many features of a natural sensitive clay, such as the evolving anisotropic strength-stiffness response, as well as the degradation of the initial bonding. A sensitivity analysis is performed varying the overconsolidation ratio (QCR), bonding and anisotropy, also the hydraulic conductivity (hence, cv) of the clay. The findings indicate that some soil properties (the cv and OCR) impact both the normalised cone resistance Qt and the generation of excess porewater pressures. In contrast the sensitivity St of soft soils primarily affects Qt. In the current work it seems that the effects of the inherent and stress induced (from CPT penetration) anisotropy is not detected using these normalised plots

Ancient variation of the AvrPm17 gene in powdery mildew limits the effectiveness of the introgressed rye Pm17 resistance gene in wheat

Introgressions of chromosomal segments from related species into wheat are important sources of resistance against fungal diseases. The durability and effectiveness of introgressed resistance genes upon agricultural deployment is highly variable-a phenomenon that remains poorly understood, as the corresponding fungal avirulence genes are largely unknown. Until its breakdown, the Pm17 resistance gene introgressed from rye to wheat provided broad resistance against powdery mildew (Blumeria graminis). Here, we used quantitative trait locus (QTL) mapping to identify the corresponding wheat mildew avirulence effector AvrPm17. It is encoded by two paralogous genes that exhibit signatures of reoccurring gene conversion events and are members of a mildew sublineage specific effector cluster. Extensive haplovariant mining in wheat mildew and related sublineages identified several ancient virulent AvrPm17 variants that were present as standing genetic variation in wheat powdery mildew prior to the Pm17 introgression, thereby paving the way for the rapid breakdown of the Pm17 resistance. QTL mapping in mildew identified a second genetic component likely corresponding to an additional resistance gene present on the 1AL.1RS translocation carrying Pm17. This gene remained previously undetected due to suppressed recombination within the introgressed rye chromosomal segment. We conclude that the initial effectiveness of 1AL.1RS was based on simultaneous introgression of two genetically linked resistance genes. Our results demonstrate the relevance of pathogen-based genetic approaches to disentangling complex resistance loci in wheat. We propose that identification and monitoring of avirulence gene diversity in pathogen populations become an integral part of introgression breeding to ensure effective and durable resistance in wheat

Temporal dynamics of genetic clines of invasive European green crab (Carcinus maenas) in eastern North America

Evolutionary Applications published by John Wiley & Sons Ltd. Reproduced with the permission of the Minister of Fisheries and Oceans Canada. Two genetically distinct lineages of European green crabs (Carcinus maenas) were independently introduced to eastern North America, the first in the early 19th century and the second in the late 20th century. These lineages first came into secondary contact in southeastern Nova Scotia, Canada (NS), where they hybridized, producing latitudinal genetic clines. Previous studies have documented a persistent southward shift in the clines of different marker types, consistent with existing dispersal and recruitment pathways. We evaluated current clinal structure by quantifying the distribution of lineages and fine-scale hybridization patterns across the eastern North American range (25 locations, ~39 to 49°N) using informative single nucleotide polymorphisms (SNPs; n = 96). In addition, temporal changes in the genetic clines were evaluated using mitochondrial DNA and microsatellite loci (n = 9–11) over a 15-year period (2000–2015). Clinal structure was consistent with prior work demonstrating the existence of both northern and southern lineages with a hybrid zone occurring between southern New Brunswick (NB) and southern NS. Extensive later generation hybrids were detected in this region and in southeastern Newfoundland. Temporal genetic analysis confirmed the southward progression of clines over time; however, the rate of this progression was slower than predicted by forecasting models, and current clines for all marker types deviated significantly from these predictions. Our results suggest that neutral and selective processes contribute to cline dynamics, and ultimately, highlight how selection, hybridization, and dispersal can collectively influence invasion success

Wheat Pm4 resistance to powdery mildew is controlled by alternative splice variants encoding chimeric proteins

Crop breeding for resistance to pathogens largely relies on genes encoding receptors that confer race-specific immunity. Here, we report the identification of the wheat Pm4 race-specific resistance gene to powdery mildew. Pm4 encodes a putative chimeric protein of a serine/threonine kinase and multiple C2 domains and transmembrane regions, a unique domain architecture among known resistance proteins. Pm4 undergoes constitutive alternative splicing, generating two isoforms with different protein domain topologies that are both essential for resistance function. Both isoforms interact and localize to the endoplasmatic reticulum when co-expressed. Pm4 reveals additional diversity of immune receptor architecture to be explored for breeding and suggests an endoplasmatic reticulum-based molecular mechanism of Pm4-mediated race-specific resistance

Attrahera Generation Y : En studie om hur Karlstads kommun kan attrahera framtidens arbetare

Denna uppsats har till syfte att redogöra för Generation Y och vad Karlstads kommun bör tänka på i kommande rekrytering av denna målgrupp. Generation Y trädde in på arbetsmarknaden runt millennieskiftet och förväntas nu ta över efter den stora andel äldre som snart lämnar sina arbeten och blir pensionärer. Till följd av att det föreligger ett stort rekryteringsbehov inom kommunal verksamhet under kommande tioårsperiod såg vi här ett problemområde som var intressant att forska vidare i. I arbetet med att klargöra attribut som är signifikativt för just Generation Y föll det sig naturligt att också se vad som kännetecknar tidigare generationer för att på så sätt reda ut vad som skiljer dessa åt. Studien är uppbyggd på en kvalitativ intervjustudie som utgörs av sju halvstrukturerade forskningsintervjuer. Den teoretiska bakgrunden bygger på tidigare forskning och redogör för relevanta begrepp inom området, däribland Employer Branding och Generation Y. Resultatet av vår studie visar vad som är attraktivt i arbetet för Generation Y och vi sammanfattar detta i de fem kategorierna; mening, möjligheter, trygghet, social interaktion och kommunikation. Det är emellertid viktigt att tänka på att det inom detta område finns begränsat med tidigare forskning. Detta betyder att det inte är helt oproblematiskt att generalisera en hel generation, vi ser också ett behov av ytterligare forskning om Generation Y

A fictional field case study to understand the genetic basis of host-fungal pathogen interactions using the wheat powdery mildew-wheat pathosystem

Wheat powdery mildew is an important fungal pathogen of wheat with an obligatory biotrophic lifestyle (a parasite that can only develop on a living host). We investigated the genetics of this host-pathogen interaction by using phenotyping and PCR assays to detect genes in both wheat and powdery mildew, which are known determinants of the outcome of these interactions (resistance or susceptibility). The mildew genes increase or decrease the pathogen virulence, while the wheat genes provide specific immunity against the mildew isolates expressing the corresponding avirulence genes. Here, we describe the experiments performed to understand the genetic basis of race-specific resistance of wheat to powdery mildew, which is part of the course ‘Mechanisms of Plant Disease Resistance against Fungal Pathogens’ designed for advanced third-year students of biology at the University of Zurich, Switzerland. In this course, students learn how plants and their pathogenic fungi engage in an arms race against each other to survive

The AvrPm3-Pm3 effector-NLR interactions control both race-specific resistance and host-specificity of cereal mildews on wheat

The wheat Pm3 resistance gene against the powdery mildew pathogen occurs as an allelic series encoding functionally different immune receptors which induce resistance upon recognition of isolate-specific avirulence (AVR) effectors from the pathogen. Here, we describe the identification of five effector proteins from the mildew pathogens of wheat, rye, and the wild grass Dactylis glomerata, specifically recognized by the PM3B, PM3C and PM3D receptors. Together with the earlier identified AVRPM3A2/F2, the recognized AVRs of PM3B/C, (AVRPM3B2/C2), and PM3D (AVRPM3D3) belong to a large group of proteins with low sequence homology but predicted structural similarities. AvrPm3b2/c2 and AvrPm3d3 are conserved in all tested isolates of wheat and rye mildew, and non-host infection assays demonstrate that Pm3b, Pm3c, and Pm3d are also restricting the growth of rye mildew on wheat. Furthermore, divergent AVR homologues from non-adapted rye and Dactylis mildews are recognized by PM3B, PM3C, or PM3D, demonstrating their involvement in host specificity

Data from: Temporal dynamics of the genetic clines of invasive European green crab (Carcinus maenas) in eastern North America

Two genetically distinct lineages of European green crabs (Carcinus maenas) were independently introduced to eastern North America, the first in the early 19th century and the second in the late 20th century. These lineages first came into secondary contact in southeastern Nova Scotia, Canada (NS), where they hybridized, producing latitudinal genetic clines. Previous studies have documented a persistent southward shift in the clines of different marker types, consistent with existing dispersal and recruitment pathways. We evaluated current clinal structure by quantifying the distribution of lineages and fine-scale hybridization patterns across the eastern North American range (25 locations, ~39-49°N) using informative single nucleotide polymorphisms (SNPs; n=96). In addition, temporal changes in the genetic clines were evaluated using mitochondrial DNA and microsatellite loci (n=9-11) over a 15-year period (2000-2015). Clinal structure was consistent with prior work demonstrating the existence of both northern and southern lineages with a hybrid zone occurring between southern New Brunswick (NB) and southern NS. Extensive later generation hybrids were detected in this region and in southeastern Newfoundland. Temporal genetic analysis confirmed the southward progression of clines over time; however, the rate of this progression was slower than predicted by forecasting models, and current clines for all marker types deviated significantly from these predictions. Our results suggest that neutral and selective processes contribute to cline dynamics, and ultimately, highlight how selection, hybridization, and dispersal can collectively influence invasion success