Uniqueness of static spherically symmetric vacuum solutions in the IR limit of Ho\v{r}ava-Lifshitz gravity

We investigate static spherically symmetric vacuum solutions in the IR limit of projectable nonrelativistic quantum gravity, including the renormalisable quantum gravity recently proposed by Ho\v{r}ava. It is found that the projectability condition plays an important role. Without the cosmological constant, the spacetime is uniquely given by the Schwarzschild solution. With the cosmological constant, the spacetime is uniquely given by the Kottler (Schwarzschild-(anti) de Sitter) solution for the entirely vacuum spacetime. However, in addition to the Kottler solution, the static spherical and hyperbolic universes are uniquely admissible for the locally empty region, for the positive and negative cosmological constants, respectively, if its nonvanishing contribution to the global Hamiltonian constraint can be compensated by that from the nonempty or nonstatic region. This implies that static spherically symmetric entirely vacuum solutions would not admit the freedom to reproduce the observed flat rotation curves of galaxies. On the other hand, the result for locally empty regions implies that the IR limit of nonrelativistic quantum gravity theories does not simply recover general relativity but includes it.Comment: 10 pages, accepted for publication in International Journal of Modern Physics

Desingularization of matrix equations employing hypersingular integrals in boundary element methods using double nodes

In boundary element methods, the method of using double nodes at corners is a useful approach to uniquely define the normal direction of boundary elements. However, matrix equations constructed by conventional boundary integral equations (CBIE) become singular under certain combinations of double node boundary conditions. In this paper, we analyze the singular conditions of the CBIE formulation for cases where the boundary conditions at the double node are imposed by combinations of Dirichlet, Neumann, Robin, and interface conditions. To address this singularity we propose the use of hypersingular integral equations (HBIE) for wave propagation problems that obey Helmholtz equation. To demonstrate the applicability of HBIE, we compare three types of simultaneous equations: (i) CBIE, (ii) partial-HBIE in which HBIE is only applied to the double nodes at corners while CBIE is applied to the other nodes, and (iii) full-HBIE in which HBIE is applied to all nodes. Based on our numerical results, we observe the following results. The singularity of the matrix equations for problems with any combination of boundary conditions can be resolved by both full-HBIE and partial-HBIE, and partial-HBIE exhibits better accuracy than full-HBIE. Furthermore, the computational cost of partial-HBIE is smaller than that of full-HBIE.Comment: 14 pages, 10 figures, accepted manuscript submitted to Engineering Analysis with Boundary Elemen

Molecular Imaging in Endoscopy

During the last decade, researchers have made great progress in the development of new image processing technologies for gastrointestinal endoscopy. However, diagnosis using conventional endoscopy with white light optical imaging is essentially limited, and ultimately, we still rely on the histopathological diagnosis from biopsy specimens. Molecular imaging represents the most novel imaging methods in medicine, and the future of endoscopic diagnosis is likely to be impacted by a combination of biomarkers and technology. Endoscopic molecular imaging can be defined as the visualization of molecular characteristics with endoscopy. These innovations will allow us not only to locate a tumor or dysplastic lesion but also to visualize its molecular characteristics and the activity of specific molecules and biological processes that affect tumor behavior and/or its response to therapy. In the near future, these promising technologies will play a central role in endoluminal oncology

Wavefront restoration from lateral shearing data using spectral interpolation

Although a lateral-shear interferometer is robust against optical component vibrations, its interferogram provides information about differential wavefronts rather than the wavefronts themselves, resulting in the loss of specific frequency components. Previous studies have addressed this limitation by measuring four interferograms with different shear amounts to accurately restore the two-dimensional wavefront. This study proposes a technique that employs spectral interpolation to reduce the number of required interferograms. The proposed approach introduces an origin-shift technique for accurate spectral interpolation, which in turn is implemented by combining two methods: natural extension and least-squares determination of ambiguities in uniform biases. Numerical simulations confirmed that the proposed method accurately restored a two-dimensional wavefront from just two interferograms, thereby indicating its potential to address the limitations of the lateral-shear interferometer.Comment: 11 pages, 6 figure

Endoscopy in Nonvariceal UGI Bleeding

Nonvariceal upper gastrointestinal (GI) bleeding is one of the most common reasons for hospitalization and a major cause of morbidity and mortality worldwide. Recently developed endoscopic devices and supporting apparatuses can achieve endoscopic hemostasis with greater safety and efficiency. With these advancements in technology and technique, gastroenterologists should have no concerns regarding the management of acute upper GI bleeding, provided that they are well prepared and trained. However, when endoscopic hemostasis fails, endoscopy should not be continued. Rather, endoscopists should refer patients to radiologists and surgeons without any delay for evaluation regarding the appropriateness of emergency interventional radiology or surgery

Cyclic Oligosaccharide-Induced Modulation of Immunoglobulin A Reactivity to Gut Bacteria Contributes to Alterations in the Bacterial Community Structure

Immunoglobulin A (IgA) is a major gut antibody that coats commensal gut bacteria and contributes to shaping a stable gut bacterial composition. Although previous studies have shown that cyclic oligosaccharides, including cyclic nigerosyl-1,6-nigerose (CNN) and cyclodextrins (CDs, including alpha CD, beta CD, and gamma CD), alter the gut bacterial composition, it remains unclear whether cyclic oligosaccharides modify the IgA coating of gut bacteria, which relates to cyclic oligosaccharide-induced alteration of the gut bacterial composition. To address this issue, mice were maintained for 12 weeks on diets containing CNN, alpha CD, beta CD, or gamma CD; the animals' feces were evaluated for their bacterial composition and the IgA coating index (ICI), a measure of the degree of IgA coating of bacteria. We observed that the intake of each cyclic oligosaccharide altered the gut bacterial composition, with changes in the ICI found at both the phylum and genus levels. The ICI for Bacillota, Lachnospiraceae NK4A136 group, UC Lachnospiraceae, and Tuzzerella were significantly and positively correlated with the relative abundance (RA) in total bacteria for these bacteria; in contrast, significant correlations were not seen for other phyla and genera. Our observations suggest that cyclic oligosaccharide-induced modulation of the IgA coating of gut bacteria may partly relate to changes in the community structure of the gut bacteria

Quantum algorithm for the Vlasov simulation of the large-scale structure formation with massive neutrinos

Miyamoto K., Yamazaki S., Uchida F., et al. Quantum algorithm for the Vlasov simulation of the large-scale structure formation with massive neutrinos. Physical Review Research 6, 013200 (2024); https://doi.org/10.1103/PhysRevResearch.6.013200.Investigating the cosmological implication of the fact that neutrino has finite mass is of importance for fundamental physics. In particular, massive neutrino affects the formation of the large-scale structure (LSS) of the universe, and, conversely, observations of the LSS can give constraints on the neutrino mass. Numerical simulations of the LSS formation including massive neutrino along with conventional cold dark matter is thus an important task. For this, calculating the neutrino distribution in the phase space by solving the Vlasov equation is a suitable approach, but it requires solving the PDE in the (6+1)-dimensional space and is thus computationally demanding: Configuring ngr grid points in each coordinate and nt time grid points leads to O(ngr6) memory space and O(ntngr6) queries to the coefficients in the discretized PDE. We propose a quantum algorithm for this task. Linearizing the Vlasov equation by neglecting the relatively weak self-gravity of the neutrino, we perform the Hamiltonian simulation to produce quantum states that encode the phase-space distribution of neutrino. We also propose a way to extract the power spectrum of the neutrino density perturbations as classical data from the quantum state by quantum amplitude estimation with accuracy ϵ and query complexity of order Õ[(ngr+nt)/ϵ]. Our method also reduces the space complexity to O[polylog(ngr/ϵ)] in terms of the qubit number, while using quantum random access memories with O(ngr3) entries. As far as we know, this is the first quantum algorithm for the LSS simulation that outputs the quantity of practical interest with guaranteed accuracy

Development of an optimal laser for chirp cooling of positronium based on chirped pulse-train generator

We report the development and characterization of a pulsed 243 nm laser that is optimal for the cooling of positronium (Ps). The laser, which is based on the recent chirped pulse-train generator (CPTG) demonstrated by K. Yamada et al. (Phys. Rev. Appl. 16, 014009 (2021)), was designed to output a train of pulses with linewidths of 10 GHz, and with the center frequency of each pulse shifting upward (up-chirped) in time by $4.9\times10^2\,\mathrm{GHz\,\mu s^{-1}}$. These parameters were determined by the mechanism of chirp cooling, which is the best scheme for cooling many Ps atoms to the recoil temperature of laser cooling. To achieve the designed performance, we drove an optical phase modulator in the CPTG with a deep modulation depth based on the operating principle of the cooling laser. Time-resolved spectroscopic measurements confirmed that the developed laser satisfied the chirp rate and linewidth requirements for efficient chirp cooling. Combined with pulse energy of hundreds of microjoules, we believe that the experimental demonstration of Ps laser cooling has become possible using realistic methods for the generation and velocity measurement of Ps.Comment: 11 pages, 11 figure

DIP during perioperative chemotherapy

Purpose : Drug-induced interstitial pneumonia (DIP) that occurs during chemotherapy for breast cancer is a rare but a serious adverse event. Treatments of DIP requires interruption of breast cancer treatment, which may affect the patient’s prognosis. However, there are few reports which discuss DIP during breast cancer treatments. Purpose of this report is to make clear how DIP occurred and influenced breast cancer treatment in our hospital. Patients and Methods : A total of 74 patients who started perioperative chemotherapy in Tokushima Municipal Hospital for breast cancer from January 2019 to December 2020 were evaluated for DIP. Patients’ and tumors’ characteristics, and regimens which caused DIP were investigated. The clinical courses of the DIP patients were also followed up. Results : Twelve of the 74 patients developed DIP. All 12 patients had histories of cyclophosphamide administration ; however, the causative drug could not be determined. Ten of the 12 patients were treated with steroids, and all the patients recovered ultimately from the interstitial pneumonia. While chemotherapy was administered in six patients after mild DIP, no relapse of pneumonia was observed. Conclusion : DIP during perioperative chemotherapy for breast cancer was resolved with appropriate treatment. Patients were able to resume breast cancer treatment with minimal interruption