Phase diagrams of correlated electrons: systematic corrections to the mean field theory

Perturbative corrections to the mean field theory for particle-hole instabilities of interacting electron systems are computed within a scheme which is equivalent to the recently developed variational approach to the Kohn-Luttinger superconductivity. This enables an unbiased comparison of particle-particle and particle-hole instabilities within the same approximation scheme. A spin-rotation invariant formulation for the particle-hole instabilities in the triplet channel is developed. The method is applied to the phase diagram of the t-t' Hubbard model on the square lattice. At the Van Hove density, antiferromagnetic and d-wave Pomeranchuk phases are found to be stable close to half filling. However, the latter phase is confined to an extremely narrow interval of densities and away from the singular filling, d-wave superconducting instability dominates

The effect of soil conditioner on the spatial variability of soil environment

ArticleThe aim of the study was to assess and evaluate the effect of soil conditioner on the spatial variability of soil environment. Activator PRP-SOL conditioning soil properties was selected as a field of study. Assessment of soil environment was done through the evaluation of selected soil properties, namely, tensile resistance of the soil and soil infiltration ability. Two dose of PRP-SOL application was done twice in year 2015 (Autumn and Spring) and once in 2016 (Spring) with application rates 150 kg ha-1 and 140 kg ha-1 , respectively. The area was divided into blocks where stimulators were applied and none treated as a control. The evaluation of recorded values showed that treatability and tillage itself was significantly better on the area which was treated by application of PRP-SOL activators. In addition, tensile resistance was decreased by 5.71% in comparison with non-treated area of experimental field. Since the infiltration ability is among the very important soil properties which have an effect on soil moisture regime as well as surface runoff and therefore soil erosion. The evaluation of recorded values has revealed the effect of treatment by PRP-SOL activators on soil infiltration ability and therefore it results in increases infiltration of precipitation as well. Overall increase of infiltration was recorded at value 2 mm h -1 . It can be concluded that application of soil activators may increase the soil conditions and therefore not only conserve soil fertility but even increase it from the long term perspective

Anthropogenic disturbance as a driver of microspatial and microhabitat segregation of cytotypes of Centaurea stoebe and cytotype interactions in secondary contact zones

Background and Aims In a mixed-ploidy population, strong frequency-dependent mating will lead to the elimination of the less common cytotype, unless prezygotic barriers enhance assortative mating. However, such barriers favouring cytotype coexistence have only rarely been explored. Here, an assessment is made of the mechanisms involved in formation of mixed-ploidy populations and coexistence of diploid plants and their closely related allotetraploid derivates from the Centaurea stoebe complex (Asteraceae). Methods An investigation was made of microspatial and microhabitat distribution, life-history and fitness traits, flowering phenology, genetic relatedness of cytotypes and intercytotype gene flow (cpDNA and microsatellites) in six mixed-ploidy populations in Central Europe. Key Results Diploids and tetraploids were genetically differentiated, thus corroborating the secondary origin of contact zones. The cytotypes were spatially segregated at all sites studied, with tetraploids colonizing preferentially drier and open microhabitats created by human-induced disturbances. Conversely, they were rare in more natural microsites and microsites with denser vegetation despite their superior persistence ability (polycarpic life cycle). The seed set of tetraploid plants was strongly influenced by their frequency in mixed-ploidy populations. Triploid hybrids originated from bidirectional hybridizations were extremely rare and almost completely sterile, indicating a strong postzygotic barrier between cytotypes. Conclusions The findings suggest that tetraploids are later immigrants into already established diploid populations and that anthropogenic activities creating open niches favouring propagule introductions were the major factor shaping the non-random distribution and habitat segregation of cytotypes at fine spatial scale. Establishment and spread of tetraploids was further facilitated by their superior persistence through the perennial life cycle. The results highlight the importance of non-adaptive spatio-temporal processes in explaining microhabitat and microspatial segregation of cytotype

The IDEAL (Insulin therapy DE-intensificAtion with iglarLixi) randomised controlled trial—study design and protocol

Introduction Multiple daily injection insulin regimen (MDI) represents the most intensive insulin regimen used in the management of people with type 2 diabetes (PwT2D). Its efficacy regarding glycaemic control is counterbalanced by the increased risk of hypoglycaemia, frequently observed tendency to weight gain and necessity for frequent glucose monitoring. Recent introduction of novel antidiabetic medications with pleiotropic effects reaching far beyond the reduction of glycaemia (HbA1c), such as the glucagon-like peptide 1 receptor agonist (GLP-1 RA), has significantly widened the therapeutic options available for management of T2D. Consequently, there is currently a substantial number of PwT2D for whom the MDI regimen was initiated at a time when no other options were available. Yet, in present times, these individuals could benefit from simplified insulin regimens ideally taking advantage of the beneficial effects of the novel classes of antidiabetic medications. iGlarLixi (Suliqua®) is a once-daily fixed-ratio combination of basal insulin analogue glargine 100 U/ml and a GLP-1 RA lixisenatide. Methods Insulin therapy DE-intensificAtion with iglarLixi (IDEAL) is a six-centre, open-label, parallel-group, active comparator, phase IV randomised controlled trial with a 24-week active treatment period examining the efficacy and safety of MDI regimen de-intensification with once-daily administration of iGlarLixi versus MDI regimen continuation in PwT2D on a backgroud therapy with metformin ± sodium-glucose cotransporter 2 inhibitor. Planned Outcomes The primary objective is to compare the effects of MDI therapy de-intensification with iGlarLixi versus MDI regimen continuation regarding glycaemic control (HbA1c). Secondary objectives include detailed evaluation of the effects of MDI regimen de-intensification with iGlarLixi on glycaemic control using standardised continuous glucose monitoring (CGM) metrics and self-monitoring of plasma glucose. Furthermore, body weight and body composition analysis, quality of life and safety profile are evaluated. Trial Registration ClinicalTrials.gov, identifier NCT04945070

Alpine Crossroads or Origin of Genetic Diversity? Comparative Phylogeography of Two Sympatric Microgastropod Species

The Alpine Region, constituting the Alps and the Dinaric Alps, has played a major role in the formation of current patterns of biodiversity either as a contact zone of postglacial expanding lineages or as the origin of genetic diversity. In our study, we tested these hypotheses for two widespread, sympatric microgastropod taxa – Carychium minimum O.F. Müller, 1774 and Carychium tridentatum (Risso, 1826) (Gastropoda, Eupulmonata, Carychiidae) – by using COI sequence data and species potential distribution models analyzed in a statistical phylogeographical framework. Additionally, we examined disjunct transatlantic populations of those taxa from the Azores and North America. In general, both Carychium taxa demonstrate a genetic structure composed of several differentiated haplotype lineages most likely resulting from allopatric diversification in isolated refugial areas during the Pleistocene glacial periods. However, the genetic structure of Carychium minimum is more pronounced, which can be attributed to ecological constraints relating to habitat proximity to permanent bodies of water. For most of the Carychium lineages, the broader Alpine Region was identified as the likely origin of genetic diversity. Several lineages are endemic to the broader Alpine Region whereas a single lineage per species underwent a postglacial expansion to (re)colonize previously unsuitable habitats, e.g. in Northern Europe. The source populations of those expanding lineages can be traced back to the Eastern and Western Alps. Consequently, we identify the Alpine Region as a significant ‘hot-spot’ for the formation of genetic diversity within European Carychium lineages. Passive dispersal via anthropogenic means best explains the presence of transatlantic European Carychium populations on the Azores and in North America. We conclude that passive (anthropogenic) transport could mislead the interpretation of observed phylogeographical patterns in general