452 research outputs found
The Algebra of Physical Observables in Nonlinearly Realized Gauge Theories
We classify the physical observables in spontaneously broken nonlinearly
realized gauge theories in the recently proposed loopwise expansion governed by
the Weak Power-Counting (WPC) and the Local Functional Equation. The latter
controls the non-trivial quantum deformation of the classical nonlinearly
realized gauge symmetry, to all orders in the loop expansion. The
Batalin-Vilkovisky (BV) formalism is used. We show that the dependence of the
vertex functional on the Goldstone fields is obtained via a canonical
transformation w.r.t. the BV bracket associated with the BRST symmetry of the
model. We also compare the WPC with strict power-counting renormalizability in
linearly realized gauge theories. In the case of the electroweak group we find
that the tree-level Weinberg relation still holds if power-counting
renormalizability is weakened to the WPC condition.Comment: 20 pages, 1 figur
High-density linkage mapping and QTL identification of black rot resistance towards marker-assisted breeding in grapevine
Today sustainability is a pivotal objective for viticulture, but it also presents us with new challenges. The decrease in treatments has in fact changed grapevine-pathogen interactions and dynamics causing the reaffirmation of diseases previously considered secondary. This is the case of black rot (BR, caused by Phyllosticta ampelicida), which is spreading with increasing pressure in warm-humid regions causing the loss of entire crops. The interinstitutional DAMAGE project between Edmund Mach Foundation (FEM) and the Institute for Grapevine Breeding (JKI-Geilweilerhof) aims to characterize BR resistance and to develop a toolkit of molecular markers (MM) to be routinely used in marker-assisted breeding for the introgression of this trait into mildew resistant backgrounds. The first fungal strain was isolated from infected leaves collected in Trentino-Italy and mixed with a second strain isolated in southwestern Germany. This inoculum has been used to screen a segregating population derived from 'Merzling' (V. rupestris × V. lincecumii, mid-resistant) × 'Teroldego' (V. vinifera, susceptible). BR resistance phenotyping consisted of a newly developed inoculation protocol on potted plants. The F1 individuals were genotyped with the Vitis18KSNP chip and a high-density genetic map has been constructed, following the integration of 190 informative SSRs. Moreover, explorative QTL analyzes have been conducted on phenotypic data of 2020 and 2021 seasons. Finally, upon the genomic interval characterization, new MM will be designed, tested and validated on various segregating populations with different genetic backgrounds
Towards Marker-Assisted Breeding for Black Rot Bunch Resistance: Identification of a Major QTL in the Grapevine Cultivar 'Merzling'
Black rot (BR), caused by Guignardia bidwellii, is an emergent fungal disease threatening viticulture and affecting several mildew-tolerant varieties. However, its genetic bases are not fully dissected yet. For this purpose, a segregating population derived from the cross 'Merzling' (hybrid, resistant) × 'Teroldego' (V. vinifera, susceptible) was evaluated for BR resistance at the shoot and bunch level. The progeny was genotyped with the GrapeReSeq Illumina 20K SNPchip, and 7175 SNPs were combined with 194 SSRs to generate a high-density linkage map of 1677 cM. The QTL analysis based on shoot trials confirmed the previously identified Resistance to Guignardia bidwellii (Rgb)1 locus on chromosome 14, which explained up to 29.2% of the phenotypic variance, reducing the genomic interval from 2.4 to 0.7 Mb. Upstream of Rgb1, this study revealed a new QTL explaining up to 79.9% of the variance for bunch resistance, designated Rgb3. The physical region encompassing the two QTLs does not underlie annotated resistance (R)-genes. The Rgb1 locus resulted enriched in genes belonging to phloem dynamics and mitochondrial proton transfer, while Rgb3 presented a cluster of pathogenesis-related Germin-like protein genes, promoters of the programmed cell death. These outcomes suggest a strong involvement of mitochondrial oxidative burst and phloem occlusion in BR resistance mechanisms and provide new molecular tools for grapevine marker-assisted breeding
Rgb3: an organ-specific QTL for bunch resistance to black rot identified in the hybrid cultivar ‘Merzling’ Hands-on demo of the potential of Grapedia
Crops are continuously exposed to the onset of emerging diseases and the exploitation of resistance donors in breeding programs is a widely used valid strategy. In the last two decades black rot (BR), caused by the ascomycete Phyllosticta ampelicida (syn. Guignardia bidwellii), has begun to threaten European viticulture in humid continental areas due to the advent of higher temperatures which favor the pathogenic cycle of the fungus. For this reason, a program has been established for the dissection of BR resistance trait and its introgression both in Vitis vinifera varieties and mildew resistant hybrids. A preliminary study was carried out to improve germplasm screening through different approaches. Historical phenotypic and pedigree information of resistance donors were gathered to support the decision-making process in breeding. A new propagation and inoculation strategy was developed to optimize and fasten inoculation experiments. Isolates of P. ampelicida were genetically characterized and combined for the assessment of resistance independent of race-specificity. Finally, these improvements were employed first for the identification of new BR resistant parental lines and breeding selections, and then for the quantitative trait locus (QTL) analysis in a segregating population derived from the cross ‘Merzling’ (hybrid, resistant) × ‘Teroldego’ (V. vinifera, susceptible). The screening of this progeny, under green-house and field conditions, allowed the discrimination between two distinct organ-specific QTLs on chromosome 14. The previously identified Resistance to G. bidwellii (Rgb)1 locus was confirmed associated with leaf/shoot resistance, while upstream a new QTL designated Rgb3 was discovered linked to bunch resistance. Driven and inspired by the INTEGRAPE community effort that led to GRAPEDIA (GRAPEvine -omics encyclopDIA), all the available tools and resources have been exploited for the exploration of the physical region of the two QTLs, providing a hands-on demo of the potential of this portal
Highly dense linkage mapping and identification of a major QTL associated with BLACK ROT resistance in the grapevine cultivar ‘Merzling’
When the urgency of a sustainable transition comes to agriculture, one of the key areas of improvement involves the decrease of chemicals. Although vineyards cover less than 5% of agricultural land in Europe, viticulture is responsible for the use of more than 60% of all fungicides. The exploitation of grapevine varieties resistant to mildews is an efficient strategy already implemented in integrated/organic farming to reduce treatments. However, from the beginning of this century, European viticulture has been threatened by severe outbreaks of black rot (BR), an emergent and destructive disease caused by the ascomycete Phyllosticta ampelicida (sexual morph Guignardia bidwellii). These events introduced the urgent need for the introgression of BR resistance in mildew-tolerant genotypes. For this purpose, a set of parental lines and breeding selections of the Fondazione Edmund Mach has been screened for BR resistance in a growing chamber with in vivo produced spores using an optimized artificial infection protocol. Given the good performance of ‘Merzling’ (a complex genotype derived from V. vinifera and V. rupestris × V. aestivalis var. lincecumii), this cultivar was used for a cross with the susceptible variety ‘Teroldego’ (V. vinifera) and the segregating offspring was genetically characterized by means of the GrapeReSeq 18K Vitis SNP chip. Five phenotypic experiments were carried out under controlled conditions on leaves of potted plants, and three on bunches in the field. A dense genetic map was constructed combining 7,175 SNP with 194 SSR markers of a previous map. All QTL analyses revealed the presence of a strong major BR resistance locus on chromosome 14. It explains up to 45% of the trait variability (LOD 10.5) and spans a genomic region of 1.36 Mb. A specific SNP marker was found robustly associated with the resistance trait. No minor QTLs were detected. The genes underlying this region are currently under investigation via bioinformatic analysis, and microscopic inspections of disease progression are in place to understand the biological causes of the resistance trait. Finally, new molecular markers will be developed and validated on segregating populations with different genetic backgrounds, to be implemented in marker-assisted selection for BR resistance in grapevin
The electronic structure of zircon-type orthovanadates: Effects of high-pressure and cation substitution
The electronic structure of four ternary-metal oxides containing isolated
vanadate ions is studied. Zircon-type YVO4, YbVO4, LuVO4, and NdVO4 are
investigated by high-pressure optical-absorption measurements up to 20 GPa.
First-principles calculations based on density-functional theory were also
performed to analyze the electronic band structure as a function of pressure.
The electronic structure near the Fermi level originates largely from molecular
orbitals of the vanadate ion, but cation substitution influence these
electronic states. The studied ortovanadates, with the exception of NdVO4,
undergo a zircon-scheelite structural phase transition that causes a collapse
of the band-gap energy. The pressure coefficient dEg/dP show positive values
for the zircon phase and negative values for the scheelite phase. NdVO4
undergoes a zircon-monazite-scheelite structural sequence with two associated
band-gap collapses.Comment: 35 pages, 11 figures, 2 Tables, 52 reference
Black rot resistance of grapevine: from organ-specific QTL mapping to the sequencing of the donor towards candidate gene identification
Black rot is considered one of the most problematic emerging fungal diseases in Europe due to the increasing pressure favored by climate change, its destructiveness – which can lead up to 80% of fruit loss – and the susceptibility of a large part of the mildew resistant varieties, so-called PIWI. Therefore, in the perspective of the genomic designing of the cultivars of the future, modern breeding has to focus on the combination of multiple beneficial alleles both for disease resistance and abiotic stress resilience. Doubtless, the genetic dissection of the traits of interest is a necessary starting point. To this objective, the segregation of black rot resistance has been studied in a population (N=147) derived from the cross between the resistant Vitis hybrid ‘Merzling’ and the susceptible V. vinifera ‘Teroldego’. The progeny was genotyped with the GrapeReSeq Illumina 20K SNPchip, and 7,175 SNPs were combined with 194 SSRs to generate a high-density linkage map of 1,677 cM. The outcomes uncovered two organ-specific QTLs on chromosome 14. One was associated with the resistance of shoot and co-segregated with the previously mapped Rgb1 locus. A second newly discovered QTL explained almost 70% of the phenotypic variance of bunch resistance and was designated Rgb3. The genes underlying the QTLs have been firstly studied based on the reference vinifera genome, PN40024.v4, revealing the absence of resistance (R)-genes and the enrichment of two clusters of 15 pathogenesis-related Germin-like protein 3, and five phloem Sieve occlusion element type B genes associated with bunch and shoot resistance, respectively. A molecular toolkit has been therefore designed for marker-assisted breeding applications. Finally, to propose reliable candidate genes for biotechnological approaches, the genome of the resistance donor ‘Merzling’ has been sequenced through PacBio HiFi technology. This data has been assembled into a haplotype-resolved and phased genome sequence. Preliminary results will be discussed regarding significant differences with the reference vinifera genome, which confirms the high value of exploring the genomes of hybrids. These findings corroborate the need for the scientific community to engage in building a pangenome to unveil and exploit the genetic variability and informativeness of the highly heterozygous Vitis genus
Distance statistics in large toroidal maps
We compute a number of distance-dependent universal scaling functions
characterizing the distance statistics of large maps of genus one. In
particular, we obtain explicitly the probability distribution for the length of
the shortest non-contractible loop passing via a random point in the map, and
that for the distance between two random points. Our results are derived in the
context of bipartite toroidal quadrangulations, using their coding by
well-labeled 1-trees, which are maps of genus one with a single face and
appropriate integer vertex labels. Within this framework, the distributions
above are simply obtained as scaling limits of appropriate generating functions
for well-labeled 1-trees, all expressible in terms of a small number of basic
scaling functions for well-labeled plane trees.Comment: 24 pages, 9 figures, minor corrections, new added reference
Body fluids and salt metabolism - Part II
There is a high frequency of diarrhea and vomiting in childhood. As a consequence the focus of the present review is to recognize the different body fluid compartments, to clinically assess the degree of dehydration, to know how the equilibrium between extracellular fluid and intracellular fluid is maintained, to calculate the effective blood osmolality and discuss both parenteral fluid maintenance and replacement
Breastfeeding difficulties and risk for early breastfeeding cessation
Although breast milk is the normative feeding for infants, breastfeeding rates are lower than recommended. We investigated breastfeeding difficulties experienced by mothers in the first months after delivery and their association with early breastfeeding discontinuation. We conducted a prospective observational study. Mothers breastfeeding singleton healthy term newborns at hospital discharge were enrolled and, at three months post-delivery, were administered a questionnaire on their breastfeeding experience. Association among neonatal/maternal characteristics, breastfeeding difficulties and support after hospital discharge, and type of feeding at three months was assessed using multivariate binary logistic regression analysis. We enrolled 792 mothers, 552 completed the study. Around 70.3% of mothers experienced breastfeeding difficulties, reporting cracked nipples, perception of insufficient amount of milk, pain, and fatigue. Difficulties occurred mostly within the first month. Half of mothers with breastfeeding issues felt wellsupported by health professionals. Maternal perception of not having a sufficient amount of milk, infant\u2019s failure to thrive, mastitis, and the return to work were associated with a higher risk of nonexclusive breastfeeding at three months whereas vaginal delivery and breastfeeding support after hospital discharge were associated with a decreased risk. These results underline the importance of continued, tailored professional breastfeeding support
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