Primordial black holes from Higgs inflation with a Gauss-Bonnet coupling

Primordial black holes (PBHs) can be the source for all or a part of today's dark matter density. Inflation provides a mechanism for generating the seeds of PBHs in the presence of a temporal period where the velocity of an inflaton field $\phi$ rapidly decreases toward 0. We compute the primordial power spectra of curvature perturbations generated during Gauss-Bonnet (GB) corrected Higgs inflation in which the inflaton field has not only a nonminimal coupling to gravity but also a GB coupling. For a scalar-GB coupling exhibiting a rapid change during inflation, we show that curvature perturbations are sufficiently enhanced by the appearance of an effective potential $V_{\rm eff}(\phi)$ containing the structures of plateau-type, bump-type, and their intermediate type. We find that there are parameter spaces in which PBHs can constitute all dark matter for these three types of $V_{\rm eff}(\phi)$. In particular, models with bump- and intermediate-types give rise to the primordial scalar and tensor power spectra consistent with the recent Planck data on scales relevant to the observations of cosmic microwave background. This property is attributed to the fact that the number of e-foldings $\Delta N_c$ acquired around the bump region of $V_{\rm eff}(\phi)$ can be as small as a few, in contrast to the plateau-type where $\Delta N_c$ typically exceeds the order of 10.Comment: 20 pages, 7 figure

Some relative properties on normality and paracompactness, and their absolute embeddings

summary:Paracompactness ($=2$-paracompactness) and normality of a subspace $Y$ in a space $X$ defined by Arhangel'skii and Genedi [4] are fundamental in the study of relative topological properties ([2], [3]). These notions have been investigated by primary using of the notion of weak $C$- or weak $P$-embeddings, which are extension properties of functions defined in [2] or [18]. In fact, Bella and Yaschenko [8] characterized Tychonoff spaces which are normal in every larger Tychonoff space, and this result is essentially implied by their previous result in [8] on a corresponding case of weak $C$-embeddings. In this paper, we introduce notions of $1$-normality and $1$-collectionwise normality of a subspace $Y$ in a space $X$, which are closely related to $1$-paracompactness of $Y$ in $X$. Furthermore, notions of quasi-$C^\ast$- and quasi-$P$-embeddings are newly defined. Concerning the result of Bella and Yaschenko above, by characterizing absolute cases of quasi-$C^*$- and quasi-$P$-embeddings, we obtain the following result: a Tychonoff space $Y$ is $1$-normal (or equivalently, $1$-collectionwise normal) in every larger Tychonoff space if and only if $Y$ is normal and almost compact. As another concern, we also prove that a Tychonoff (respectively, regular, Hausdorff) space $Y$ is $1$-metacompact in every larger Tychonoff (respectively, regular, Hausdorff) space if and only if $Y$ is compact. Finally, we construct a Tychonoff space $X$ and a subspace $Y$ such that $Y$ is $1$-paracompact in $X$ but not $1$-subparacompact in $X$. This is a negative answer to a question of Qu and Yasui in [25]

Musculotendinous junction tear

We report a rare case of a partial thickness tear of the supraspinatus at the musculotendinous junction in a softball catcher. Preoperative magnetic resonance images of the shoulder showed high signal intensity areas at the musculotendinous junction, along with discontinuity of the articular side of the supraspinatus. Arthroscopic examination revealed articular-side partial tear at the musculotendinous junction. The patient was able to return to playing softball 20 weeks after arthroscopic side-to-side repair

Reduction of perioperative blood loss and operating time for arthroscopic rotator cuff repair by intravenous administration of tranexamic acid

Background: Tranexamic acid (TXA) is widely used in hip and knee arthroplasty to reduce perioperative bleeding. Recently, its use has been expanded to arthroscopic surgery. The purpose of this study was to evaluate the efficacy of preoperative use of TXA in arthroscopic rotator cuff repair (RCR). Methods: A cohort comprising 129 consecutive patients who underwent arthroscopic primary RCR at our institution was retrospectively investigated according to whether they received TXA (April 2018 to December 2020, TXA group, n = 64) or did not receive TXA (April 2016 to March 2018, non-TXA group, n = 65). TXA was administered at a dose of 1 g intravenously. Rotator cuff tears were repaired by the suture bridge technique. Videos of the arthroscopic procedures were reviewed and rated for visual clarity using a 10-point numeric rating scale. Arthroscopic procedures were divided into glenohumeral, resection of bursal tissue and acromioplasty, and RCR steps. Each step was rated separately. Age, sex, body mass index, hemoglobin level before and on days 1 and 7 after surgery, operating time, mean arterial pressure, tear size, and number of anchors used for cuff repair were compared between the two groups. Results: There were no statistically significant differences in the patient demographic data. The operating time was significantly shorter in the TXA group than in non-TXA group (97.8 ± 21.8 min vs 116.2 ± 26.0 min). The clarity of the visual field was similar between the two groups during the glenohumeral phase but was significantly higher in the TXA group during the resection of bursal tissue and acromioplasty and RCR phases. Hemoglobin level was not significantly different between the groups on postoperative day 1 but was significantly higher in the TXA group on day 7. Conclusion: Administration of a single intravenous dose of TXA improved visual clarity in arthroscopic RCR, decreased the total operating time, and reduced hemoglobin loss on postoperative day 7

Weyl Starobinsky inflation

In Starobinsky inflation with a Weyl squared Lagrangian $-\alpha C^2$, where $\alpha$ is a coupling constant, we study the linear stability of cosmological perturbations on a spatially flat Friedmann-Lema\^{i}tre-Robertson-Walker background. In this theory, there are two dynamical vector modes propagating as ghosts for $\alpha>0$, whose condition is required to avoid tachyonic instabilities of vector perturbations during inflation. The tensor sector has four propagating degrees of freedom, among which two of them correspond to ghost modes. However, tensor perturbations approach constants after the Hubble radius crossing during inflation, and hence the classical instabilities are absent. In the scalar sector, the Weyl curvature gives rise to a ghost mode coupled to the scalaron arising from the squared Ricci scalar. We show that two gauge-invariant gravitational potentials, which are both dynamical in our theory, are subject to exponential growth after the Hubble radius crossing. There are particular gauge-invariant combinations like the curvature perturbations whose growth is suppressed, but it is not possible to remove the instability of other propagating degrees of freedom present in the perturbed metric. This violent and purely classical instability present in the scalar sector makes the background unviable. Furthermore, the presence of such classical instability makes the quantization of the modes irrelevant, and the homogeneous inflationary background is spoiled by the Weyl curvature term.Comment: 24 pages, 3 figure

Development of a large area gas photomultiplier with GEM/μ\muPIC

We are developing a new photon detector with micro pattern gaseous detectors. A semitransparent CsI photocathode is combined with 10cm$\times$10cm GEM/$\mu$PIC for the first prototype which is aimed for the large liquid Xe detectors. Using Ar+C$_2$H$_6$ (10%) gas, we achieved the gas gain of $10^5$ which is enough to detect single photoelectron. We, then, irradiated UV photons from a newly developed solid scintillator, LaF$_3$(Nd), to the detector and successfully detected single photoelectron.Comment: Poster presentation at ICHEP08 Philadelphia, USA, July 2008. 3 pages, LaTeX, 4 eps figure