Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

The occurrence and fine structural characterization of microbodies in the green alga Bracteococcus cinnabarinus grown heterotrophically

Includes bibliographical references.Includes illustrations.Cultures of the soil and water green alga, Bracteococcus cinnabarinus, were grown photoheterotrophically and heterotrophically on a conventional culture medium containing sodium acetate, potassium acetate and glucose as carbon sources. Control cultures were grown photoautotrophically. Ultrathin sections of cells fixed with glutaraldehyde and osmium tetroxide were examined with the electron microscope to determine the fine structural changes that may have occurred due to the different substrates and light conditions. Several changes in the ultrastructure of Bracteococcus grown photoheterotrophically and heterotrophically were observed. Disruption of the lamellae in the chloroplast, showing very little organization along with increases in the size of starch granules, was observed in cells grown heterotrophically on the acetate media. Lipid bodies which were not observed in photoautotrophically grown cells were found in all cells grown either photoheterotrophically and heterotrophically. Circular to oval microbodies ranging from 0.3 to 0.7 microns in diameter with a single limiting membrane and a homogeneous electron- dense matrix were found in close association to lipid bodies in Bracteococcus cells grown heterotrophically on sodium acetate and potassium acetate, but none were positively identified in cells maintained on the three different growth media and grown in the with cytochemical analysis of staining with diaminobenzidine (DAB). Microbodies and cristae of some mitochondria showed staining with DAB, indicating catalase activity in the microbodies and cytochromeoxidase activity in the mitochondria. Aminotriazole inhibited the DAB reactivity. Evidence from this investigation suggests that Bracteococcus, when transferred from photoautotrophic to heterotrophic conditions on acetate, will probably take up the acetate, convert it to lipid, and store it as lipid droplets. Beta-oxidation enzymes located in the glyoxysomes, induced by these conditions, convert the lipid into acetyl-coenzyme A which may in turn be converted to succinate by glyoxylate cycle enzymes. The organism may convert succinate to carbohydrates, which may be taken up by the chloroplast and converted to starch or utilized for energy. This investigation confirms the theory that the substrate and light conditions play an important role in the metabolic activity of Bracteococcus cinnabarinus and possibly other members of the Chlorophyceae, via microbody function.M.S. (Master of Science

Relapsing Fever Borreliosis in Interleukin-10-Deficient Mice▿

Relapsing fever (RF) is a spirochetal infection characterized by periods of sickness with fever at time of high bacteremia that alternate with afebrile periods of relative well being during low bacteremia. Patients with epidemic RF who are doing relatively well have extraordinarily high levels of interleukin-10 (IL-10) in the circulation. We investigated the possibility that IL-10 plays an important protective role in this infection using wild-type and IL-10-deficient mice inoculated with virulent serotype 2 of the RF spirochete Borrelia turicatae. During peak bacteremia there was increased systemic production of IL-10 that quickly resolved in the postpeak period; in contrast, IL-6 and CXCL13 production increased during the peak but remained elevated during postpeak bacteremia. IL-10 deficiency resulted in lower bacteremia, increased specific antibody production, higher production of CXCL13 and IL-6, and thrombotic and hemorrhagic complications affecting multiple organs with secondary tissue injury. Our results revealed that production of IL-10 is highly regulated during RF and plays an important protective role in the prevention of hemorrhagic and thrombotic complications at the cost of reduced pathogen control