3D Modeling of the Magnetization of Superconducting Rectangular-Based Bulks and Tape Stacks

In recent years, numerical models have become popular and powerful tools to investigate the electromagnetic behavior of superconductors. One domain where this advances are most necessary is the 3D modeling of the electromagnetic behavior of superconductors. For this purpose, a benchmark problem consisting of superconducting cube subjected to an AC magnetic field perpendicular to one of its faces has been recently defined and successfully solved. In this work, a situation more relevant for applications is investigated: a superconducting parallelepiped bulk with the magnetic field parallel to two of its faces and making an angle with the other one without and with a further constraint on the possible directions of the current. The latter constraint can be used to model the magnetization of a stack of high-temperature superconductor tapes, which are electrically insulated in one direction. For the present study three different numerical approaches are used: the Minimum Electro-Magnetic Entropy Production (MEMEP) method, the $H$-formulation of Maxwell's equations and the Volume Integral Method (VIM) for 3D eddy currents computation. The results in terms of current density profiles and energy dissipation are compared, and the differences in the two situations of unconstrained and constrained current flow are pointed out. In addition, various technical issues related to the 3D modeling of superconductors are discussed and information about the computational effort required by each model is provided. This works constitutes a concrete result of the collaborative effort taking place within the HTS numerical modeling community and will hopefully serve as a stepping stone for future joint investigations

Minimum Quench Energy and Early Quench Development in NbTi Superconducting Strands

The stability of superconducting wires is a crucial task in the design of safe and reliable superconducting magnets. These magnets are prone to premature quenches due to local releases of energy. In order to simulate these energy disturbances, various heater technologies have been developed, such as coated tips, graphite pastes, and inductive coils. The experiments studied in the present work have been performed using a single-mode diode laser with an optical fiber to illuminate the superconducting strand surface. Minimum quench energies and voltage traces at different magnetic flux densities and transport currents have been measured on an LHC-type, Cu/NbTi wire bathed in pool boiling helium I. This paper deals with the numerical analysis of the experimental data. In particular, a coupled electromagnetic and thermal model has been developed to study quench development and propagation, focusing on the influence of heat exchange with liquid helium

Electro-Thermal Behavior of Layer-Wound BSCCO Coils With and Without Insulation

In this work, the electro-thermal behavior of two layer-wound High Temperature Superconducting (HTS) coils, realized with and without electrical insulation, is compared. Both coils are wound from the same BSCCO tape, and have a very similar geometry, with the same number of turns and layers. A heat input is applied to both coils, by tuning the current supplied to resistive heaters realized through stainless steel tapes wound on the mandrel at the inner surface of both coils. The heaters are in contact with one full inner turn of the winding. The coils are cooled in a liquid nitrogen bath, and the heaters are supplied with a constant current. Then, the windings are charged until the tape critical current is exceeded, and the tests are repeated for different heat loads. The signals acquired through voltage taps, suitably soldered at the same locations in both windings, are compared at the same testing conditions. Finally, the electrical characteristic of the different layers of the coils is related to the temperature of the heater and of the various turns of the coil by means of a 1-D thermal model

The Measurement and Modeling of the Levitation Force between Single-Grain YBCO Bulk Superconductors and Permanent Magnets

The levitation force between a single grain YBCO cylindrical bulk superconductor and a permanent magnet is investigated. The force measured both in zero field cooling and field cooling condition in the temperature range 20 K - 80 K is reported. The dependence of peak levitation force and power dissipation on the temperature is analyzed and the saturation of the peak force with increasing the critical current of the material is pointed out. A numerical analysis is also carried out for understanding the electrodynamics of the levitation mechanism. Good reproduction of the measured data is obtained and relevant observed phenomena, such as hysteresis of the levitation cycle at high temperature and saturation of the peak force at low temperature, are explained by means of the model. Characterization of the material in terms of critical current density in the field range 0 T - 0.5 T is also obtained by means of the numerical model by means of the fitting of the measured data

Application of next generation semiconductor-based sequencing for the identification of apis mellifera complementary sex determiner (Csd) alleles from honey dna

The complementary sex determiner (csd) gene plays an essential role in the sex determination of Apis mellifera L. Females develop only if fertilized eggs have functional heterozygous genotypes at this gene whereas males, being haploids, are hemizygous. Two identical csd alleles produce non vital males. In light of the recent decline in honey bee populations, it is therefore important to monitor the allele variability at this gene. In this study, we tested the application of next generation semiconductor-based sequencing technology (Ion Torrent) coupled with environmental honey DNA as a source of honey bee genome information to retrieve massive sequencing data for the analysis of variability at the hypervariable region (HVR) of the csd gene. DNA was extracted from 12 honey samples collected from honeycombs directly retrieved from 12 different colonies. A specifically designed bioinformatic pipeline, applied to analyze a total of about 1.5 million reads, identified a total of 160 different csd alleles, 55% of which were novel. The average number of alleles per sample was compatible with the number of expected patrilines per colony, according to the mating behavior of the queens. Allele diversity at the csd could also provide information useful to reconstruct the history of the honey

Exploiting within-breed variability in the autochthonous Reggiana breed identified several candidate genes affecting pigmentation-related traits, stature and udder defects in cattle

Autochthonous cattle breeds constitute important reservoirs of genetic diversity. Reggiana is an Italian local cattle breed reared in the north of Italy for the production of a mono-breed Parmigiano–Reggiano cheese. Reggiana cattle usually have a classical solid red coat colour and pale muzzle. As part of the strategies designed for the sustainable conservation of this genetic resource, we investigated at the genome-wise level the within-breed detected variability of three pigmentation-related traits (intensity of red coat colour, based on three classes – light/diluted, normal and dark; spotted patterns/piebaldism that sometime emerge in the breed; muzzle colour – pink/pale, grey and black), stature, presence/absence and number of supernumerary teats and teat length. A total of 1776 Reggiana cattle (about two-thirds of the extant breed population) were genotyped with the GeneSeek GGP Bovine 150k SNP array and single-marker and haplotype-based GWASs were carried out. The results indicated that two main groups of genetic factors affect the intensity of red coat colour: darkening genes (including EDN3 and a few other genes) and diluting genes (including PMEL and a few other genes). Muzzle colour was mainly determined by MC1R gene markers. Piebaldism was mainly associated with KIT gene markers. Stature was associated with BTA6 markers upstream of the NCAPG–LCORL genes. Teat defects were associated with TBX3/TBX5, MCC and LGR5 genes. Overall, the identified genomic regions not only can be directly used in selection plans in the Reggiana breed, but also contribute to clarifying the genetic mechanisms involved in determining exterior traits in cattle

Whole Genome Sequencing Provides Information on the Genomic Architecture and Diversity of Cultivated Gilthead Seabream (Sparus aurata) Broodstock Nuclei

The gilthead seabream (Sparus aurata) is a species of relevance for the Mediterranean aquaculture industry. Despite the advancement of genetic tools for the species, breeding programs still do not often include genomics. In this study, we designed a genomic strategy to identify signatures of selection and genomic regions of high differentiation among populations of farmed fish stocks. A comparative DNA pooling sequencing approach was applied to identify signatures of selection in gilthead seabream from the same hatchery and from different nuclei that had not been subjected to genetic selection. Identified genomic regions were further investigated to detect SNPs with predicted high impact. The analyses underlined major genomic differences in the proportion of fixed alleles among the investigated nuclei. Some of these differences highlighted genomic regions, including genes involved in general metabolism and development already detected in QTL for growth, size, skeletal deformity, and adaptation to variation of oxygen levels in other teleosts. The obtained results pointed out the need to control the genetic effect of breeding programs in this species to avoid the reduction of genetic variability within populations and the increase in inbreeding level that, in turn, might lead to an increased frequency of alleles with deleterious effects

Single-marker and haplotype-based genome-wide association studies for the number of teats in two heavy pig breeds

The number of teats is a reproductive-related trait of great economic relevance as it affects the mothering ability of the sows and thus the number of properly weaned piglets. Moreover, genetic improvement of this trait is fundamental to parallelly help the selection for increased litter size. We present the results of single-marker and haplotypes-based genome-wide association studies for the number of teats in two large cohorts of heavy pig breeds (Italian Large White and Italian Landrace) including 3990 animals genotyped with the 70K GGP Porcine BeadChip and other 1927 animals genotyped with the Illumina PorcineSNP60 BeadChip. In the Italian Large White population, genome scans identified three genome regions (SSC7, SSC10, and SSC12) that confirmed the involvement of the VRTN gene (as we previously reported) and highlighted additional loci known to affect teat counts, including the FRMD4A and HOXB1 gene regions. A different picture emerged in the Italian Landrace population, with a total of 12 genome regions in eight chromosomes (SSC3, SSC6, SSC8, SSC11, SSC13, SSC14, SSC15, and SSC16) mainly detected via the haplotype-based genome scan. The most relevant QTL was close to the ARL4C gene on SSC15. Markers in the VRTN gene region were not significant in the Italian Landrace breed. The use of both single-marker and haplotype-based genome-wide association analyses can be helpful to exploit and dissect the genome of the pigs of different populations. Overall, the obtained results supported the polygenic nature of the investigated trait and better elucidated its genetic architecture in Italian heavy pigs

Thermal and rheological behavior of native and modified starch Araucaria angustifolia (pinhão).

Araucaria angustifolia is known in Brazil as Paraná Pine is endangered due to reckless extraction. The preservation and maintenance of the culture could be stimulated by use derivative products like the starch from its seeds (pinhão). In this work were studied samples of unmodified and modified pinhão starch. The hydrogen peroxide (H2O2) were used in the concentrations 0.1, 0.2 and 0.3 mol.L-1 (a, b, c) and simultaneously exposed in ultraviolet rays (λ = 256 nm) for one hour. One sample (N) was maintained as received for comparisons of the analysis results. The samples were analyzed by the thermoanalytical techniques: thermogravimetry and differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC); and by the rheological analysis: Rapid Viscoamylographic Analysis (RVA). The TGA showed an increase on the stability values form the (N) sample to the modified ones. The DSC showed a strong decrease on the gelatinization enthalpy with increasing of the H2O2 concentrations solutions valued for the modified samples. The RVA results presented that the Setback reduced with the treatment that used hydrogen peroxide in a higher concentration. The obtained results showed that the modification method applied altered the thermal behavior of the pinhão starch.CBRATEC

Nuclear mitochondrial DNA sequences in the rabbit genome

Numtogenesis is observable in the mammalian genomes resulting in the integration of mitochondrial segments into the nuclear genomes (numts). To identify numts in rabbit, we aligned mitochondrial and nuclear genomes. Alignment significance threshold was calculated and individual characteristics of numts were analysed. We found 153 numts in the nuclear genome. The GC content of numts were significantly lower than the GC content of their genomic flanking regions or the genome itself. The frequency of three mammalian-wide interspersed repeats were increased in the proximity of numts. The decreased GC content around numts strengthen the theory which supposes a link between DNA structural instability and numt integration