717 research outputs found

    Ground State of the Hydrogen Atom via Dirac Equation in a Minimal Length Scenario

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    In this work we calculate the correction to the ground state energy of the hydrogen atom due to contributions arising from the presence of a minimal length. The minimal length scenario is introduced by means of modifying the Dirac equation through a deformed Heisenberg algebra (kempf algebra). With the introduction of the Coulomb potential in the new Dirac energy operator, we calculate the energy shift of the ground state of the hydrogen atom in first order of the parameter related to the minimal length via perturbation theory.Comment: 11 page

    A bizarre foreign body in the appendix: A case report

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    Foreign bodies are rare causes of appendicitis and, in most cases, ingested foreign bodies pass through the alimentary tract asymptomatically. However, ingested foreign bodies may sometimes remain silent within the appendix for many years without an inflammatory response. Despite the fact that cases of foreign-body-induced appendicitis have been documented, sharp and pointed objects are more likely to cause perforations and abscesses, and present more rapidly after ingestion. Various materials, such as needles and drill bits, as well as organic matter, such as seeds, have been implicated as causes of acute appendicitis. Clinical presentation can vary from hours to years. Blunt foreign bodies are more likely to remain dormant for longer periods and cause appendicitis through obstruction of the appendiceal lumen. We herein describe a patient presenting with a foreign body in his appendix which had been swallowed 15 years previously. The contrast between the large size of the foreign body, the long clinical history without symptoms and the total absence of any histological inflammation was notable. We suggest that an elective laparoscopic appendectomy should be offered to such patients as a possible management optio

    Density correlations in ultracold atomic Fermi gases

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    We investigate density fluctuations in a coherent ensemble of interacting fermionic atoms. Adapting the concept of full counting statistics, well-known from quantum optics and mesoscopic electron transport, we study second-order as well as higher-order correlators of density fluctuations. Using the mean-field BCS state to describe the whole interval between the BCS limit and the BEC limit, we obtain an exact expression for the cumulant-generating function of the density fluctuations of an atomic cloud. In the two-dimensional case, we obtain a closed analytical expression. Poissonian fluctuations of a molecular condensate on the BEC side are strongly suppressed on the BCS side. The size of the fluctuations in the BCS limit is a direct measure of the pairing potential. We also discuss the BEC-BCS crossover of the third cumulant and the temperature dependence of the second cumulant.Comment: 4 pages, 4 figures. To appear in Phys. Rev. A. New calculation of the bin statistics of a free Bose gas; updated and extended bibliograph

    Assessment of Cardiorespiratory Interactions During Spontaneous and Controlled Breathing: Linear Parametric Analysis

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    In this work, we perform a linear parametric analysis of cardiorespiratory interactions in bivariate time series of heart period (HP) and respiration (RESP) measured in 19 healthy subjects during spontaneous breathing and controlled breathing at varying breathing frequency. The analysis is carried out computing measures of the total and causal interaction between HP and RESP variability in both time and frequency domains (low- and high-frequency, LF and HF). Results highlight strong cardiorespiratory interactions in the time domain and within the HF band that are not affected by the paced breathing condition. Interactions in the LF band are weaker and prevalent along the direction from HP to RESP, but result more influenced by the shift from spontaneous to controlled respiration

    Genomic organization and recombinational unit duplication-driven evolution of ovine and bovine T cell receptor gamma loci

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    <p>Abstract</p> <p>Background</p> <p>In humans and mice ("γδ low species") less than 5% of the peripheral blood T lymphocytes are gamma/delta T cells, whereas in chicken and artiodactyls ("γδ high species") gamma/delta T cells represent about half of the T cells in peripheral blood. In cattle and sheep (Bovidae) two paralogous T cell receptor gamma loci (TRG1 and TRG2) have been found. TRG1 is located on 4q3.1, within a region of homology with the human TRG locus on chromosome 7, while TRG2 localizes on 4q2.2 and appears to be unique to ruminants. The purpose of this study was the sequencing of the genomic regions encompassing both loci in a "γδ high" organism and the analysis of their evolutionary history.</p> <p>Results</p> <p>We obtained the contiguous genomic sequences of the complete sheep TRG1 and TRG2 loci gene repertoire and we performed cattle/sheep sequence analysis comparison using data available through public databases. Dot plot similarity matrix comparing the two sheep loci with each other has shown that variable (V), joining (J) and constant (C) genes have evolved through a series of duplication events involving either entire cassettes, each containing the basic V-J-J-C recombinational unit, or single V genes. The phylogenetic behaviour of the eight enhancer-like elements found in the sheep, compared with the single copy present in the human TRG locus, and evidence from concordant insertions of repetitive elements in all analyzed TRGJ blocks allowed us to infer an evolutionary scenario which highlights the genetic "flexibility" of this region and the duplication-driven evolution of gene cassettes. The strong similarity of the human and Bovidae intergenic J-J-C regions, which display an enhancer-like element at their 3' ends, further supports their key role in duplications.</p> <p>Conclusion</p> <p>We propose that only duplications of entire J-J-C regions that possessed an enhancer-like element at their 3' end, and acquired at least one V segment at their 5' end, were selected and fixed as functional recombinational units.</p

    Chairside virtual patient protocol. Part 2: Management of multiple face scans and alignment predictability

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    objectives: face scans are currently used in dentistry to obtain a virtual patient. find stable and repeatable references for their matching is a fundamental step. aim of this study is to evaluate matching reliability of multiple face scans using frontal adhesives references. null hypothesis was that no significant discrepancy could be detected between the references position analyzed both with surface analysis and linear analysis. materials and methods: nine patients were enrolled for this study and nine soft tissue adhesives landmarks (APLI paper S.A.U, 4 mm Ø) placed, equally distributed, on the forehead and glabella. patients were digitally scanned with a portable scanner (iPad Pro 3rd gen. apple store, cupertino, CA, USA) using the software bellus3D (Inc. campbell, CA, USA) in maximum intercuspation, with a full smile and with a scan reference device. after the scan procedure, a high-definition polygon file format (.ply) was exported, and linear measurements were collected with meshLab (meshLab; meshlab). In order to further evaluate reference accuracy, a surface analysis was performed using a CAD software (GOM inspect, GOM). 3D deviations were calculated as root mean square. Statistical analysis was performed used two repeated-measures ANOVAs. results: results showed non-significant differences both for linear measurements (p=.22) and surface analysis (p=.58). frontal references showed to be clinical reliable landmarks for use during face scans alignment, even with different facial expressions. conclusion: the proposed technique seems to be suitable for the clinical use when superimposition of several face scans is required. clinical significance: this study showed the clinical reliability of face scans matching method using adhesives references. these references are cheap and easy to use, allowing for a rapid registration of the patient anatomy

    Ampelographic and Molecular Characterisation of Aglianico Accessions (Vitis vinifera L.) Collected in Southern Italy

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    To characterise 31 different Aglianico accessions randomly collected in Southern Italy, 30 ampelographicdescriptors, 13 SSRs and 10 AFLP primer combinations were analysed. An appreciable variation ofampelographic descriptors was revealed mainly by mature leaf traits, while very few variations wererecorded for shoot and berry traits. Similarly, all SSR loci revealed molecular monomorphism and AFLPswith a very high genetic similarity (Dice coefficient) among all the accessions considered. One of the aimsof this study was to clarify the genetic assessment of Aglianico Nero and Aglianico del Vulture Nero,since they are registered as two different cultivars with distinct varietal codes at the Italian Register ofGrape Varieties. Registered Aglianico Nero and Aglianico del Vulture Nero were included in the analyses,compared and used as reference material. Our plants showed that all the accessions tested, independentfrom the biotype, and the two registered cultivars belong to the same genotype, suggesting that, as reportedby the Vitis International Variety Catalogue, a case of synonymy occurred between Aglianico Nero andAglianico del Vulture Nero. These cultivars could therefore be considered as a single cultivar. Moreover,the AFLP data revealed a partial match between morphological and molecular data, showing that theAFLP molecular method was able to discriminate between different accessions belonging to the samecultivar
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