Search for solar axions using Li-7

We describe a novel approach to the search for solar, near-monochromatic hadronic axions, the latter being suggested to be created in the solar core during M1 transitions between the first excited level of Li-7, at 478 keV, and the ground state. As a result of Doppler broadening, in principle these axions can be detected via resonant absorption by the same nuclide on the Earth. Excited nuclei of Li-7 are produced in the solar interior by Be-7 electron capture and thus the axions are accompanied by emission of Be-7 solar neutrinos of energy 384 keV. An experiment was made which has yielded an upper limit on hadronic axion mass of 32 keV at the 95% confidence level.Comment: revtex, 4 pages with 2 figures, title revised, minor changes, matches version to appear in Phys. Rev.

Prospects for the CERN Axion Solar Telescope Sensitivity to 14.4 keV Axions

The CERN Axion Solar Telescope (CAST) is searching for solar axions using the 9.0 T strong and 9.26 m long transverse magnetic field of a twin aperture LHC test magnet, where axions could be converted into X-rays via reverse Primakoff process. Here we explore the potential of CAST to search for 14.4 keV axions that could be emitted from the Sun in M1 nuclear transition between the first, thermally excited state, and the ground state of 57Fe nuclide. Calculations of the expected signals, with respect to the axion-photon coupling, axion-nucleon coupling and axion mass, are presented in comparison with the experimental sensitivity.Comment: 4 pages, 1 figure. Submitted to Nucl. Instr. and Meth.

An Evaluation of Image Velocimetry Techniques under Low Flow Conditions and High Seeding Densities Using Unmanned Aerial Systems

Image velocimetry has proven to be a promising technique for monitoring river flows using remotely operated platforms such as Unmanned Aerial Systems (UAS). However, the application of various image velocimetry algorithms has not been extensively assessed. Therefore, a sensitivity analysis has been conducted on five different image velocimetry algorithms including Large Scale Particle Image Velocimetry (LSPIV), Large-Scale Particle Tracking Velocimetry (LSPTV), Kanade−Lucas Tomasi Image Velocimetry (KLT-IV or KLT), Optical Tracking Velocimetry (OTV) and Surface Structure Image Velocimetry (SSIV), during low river flow conditions (average surface velocities of 0.12−0.14 m s - 1 , Q60) on the River Kolubara, Central Serbia. A DJI Phantom 4 Pro UAS was used to collect two 30-second videos of the surface flow. Artificial seeding material was distributed homogeneously across the rivers surface, to enhance the conditions for image velocimetry techniques. The sensitivity analysis was performed on comparable parameters between the different algorithms, including the particle identification area parameters (such as Interrogation Area (LSPIV, LSPTV and SSIV), Block Size (KLT-IV) and Trajectory Length (OTV)) and the feature extraction rate. Results highlighted that KLT and SSIV were sensitive to changing the feature extraction rate; however, changing the particle identification area did not affect the surface velocity results significantly. OTV and LSPTV, on the other hand, highlighted that changing the particle identification area presented higher variability in the results, while changing the feature extraction rate did not affect the surface velocity outputs. LSPIV proved to be sensitive to changing both the feature extraction rate and the particle identification area. This analysis has led to the conclusions that for surface velocities of approximately 0.12 m s - 1 image velocimetry techniques can provide results comparable to traditional techniques such as ADCPs. However, LSPIV, LSPTV and OTV require additional effort for calibration and selecting the appropriate parameters when compared to KLT-IV and SSIV. Despite the varying levels of sensitivity of each algorithm to changing parameters, all configuration image velocimetry algorithms provided results that were within 0.05 m s - 1 of the ADCP measurements, on average

A novel spi1 mutation in a patient with agammaglobulinemia

Agammaglobulinemia is a primary immunodeficiency characterized by a low number or absence of mature B lymphocytes and consequently by immunoglobulin deficiency. In 2021, six patients with pathogenic variants in SPI1 gene associated with agammaglobulinemia type 10 (PU.MA) were described for the first time. This gene encodes the pioneer transcription factor PU.1, which plays an important role in the differentiation of B lymphocytes, monocytes, and conventional dendritic cells. Here we present a female patient with a novel mutation in SPI1 gene which has not been previously found in patients with PU.MA. Case description: A 37-year-old female patient with frequent middle ear infections in early childhood was diagnosed with agammaglobulinemia at the age of 15 when she started immunoglobulin replacement therapy (IgRT). One year later, an allogeneic hematopoietic stem cell transplant from a healthy sibling donor was performed. Unfortunately, chimerism analysis found no DNA material from the donor in the patient's blood, suggesting graft rejection, so she remained dependent on antibody replacement therapy. Years later, she was diagnosed with protein-losing enteropathy, and despite escalating doses of IgRT, IgG levels remained low. Subsequently, the patient developed persistent COVID -19 viremia and bacterial meningoencephalitis. Clinical exome sequencing using the TruSight (Illumina) panel was performed and in comparision with the human reference genome (hg19), has revealed a heterozygous mutation in exon 4 of the SPI1 gene. This mutation is characterized by the insertion of 2 nucleotides (c.441dup), a reading frame shift, and the insertion of a premature stop codon. According to the American College of Medical Genetics and Genomics, this mutation is described as a likely pathogenic-class 2 (PVS1_Very Strong). Conclusion: From analysis of previous literature, we concluded that the mutant sequence in exon 4 encodes the PEST region of the pioneer transcription factor PU.1, which is responsible for interaction with other transcription factors. Immunophenotyping of peripheral blood cells did not reveal CD19+ B cells, suggesting that a differentiation arrest may have developed between the prepro-B and pro-B stages, where there is a high requirement for PU.1 activity. Nextgeneration sequencing can be a very useful tool to uncover the causes of rare primary immunodeficiencies, but further analysis is needed to explain the relationship between patient genotype and clinical presentation

Laser-induced nonresonant nuclear excitation in muonic atoms

Coherent nuclear excitation in strongly laser-driven muonic atoms is calculated. The nuclear transition is caused by the time-dependent Coulomb field of the oscillating charge density of the bound muon. A closed-form analytical expression for electric multipole transitions is derived and applied to various isotopes; the excitation probabilities are in general very small. We compare the process with other nuclear excitation mechanisms through coupling with atomic shells and discuss the prospects to observe it in experiment.Comment: 7 pages, 5 figure

Hunting up low-mass bosons from the Sun using HPGe detector

In this experiment we aim to look for keV-mass bosons emitted from the Sun, by looking at a process analogous to the photoelectric/Compton effect inside the HPGe detector. Their coupling to both electrons and nucleons is assumed. For masses above 25 keV, the mass dependence of our limit on the scalar-electron coupling reveals a constraint which proves stronger than that obtained recently and based on the very good agreement between the measured and predicted solar neutrino flux from the ^{8}B reaction. On the other hand, the mass dependence of our limit on the scalar-proton/electron coupling together entails a limit on a possible Yukawa addition to the gravitational inverse square low. Such a constraint on the Yukawa interactions proves much stronger than that derived from the latest AFM Casimir force measurement.Comment: elsarticle style, 4 eps figures, 4 pages, minor corrections, some clarifications added, to appear in Phys. Lett.