Proton Decay Signatures of Orbifold GUTs

In grand unified theories based on orbifold constructions in higher dimensions, Higgsino-mediated proton decay is absent. However, proton decay mediated by $X$ and $Y$ gauge bosons is typically enhanced to levels detectable by current and future experiments. We analyse the phenomenology of proton decay induced by the minimal coupling of $X,Y$ gauge bosons. In particular, we show that the novel realization of matter in orbifold GUTs can lead to unusual final state flavour structure, for example, the dominance of the $p\to K^0\mu^+$ mode. Furthermore, we discuss proton decay induced by higher-derivative brane operators, finding potentially observable rates for natural values of the operator coefficients.Comment: Latex, 10 pages, referencing error correcte

Electrocardiographic and Chronobiological Features of Paroxysmal AV Block Recorded by Ambulatory Electrocardiography

The goal of this study was to investigate the electrocardiographic and chronobiological features of paroxysmal atrioventricular (AV) block (PAVB) using data from ambulatory electrocardiography (AECG). The study population consisted of five men and six women aged from 47 to 82 years of age. Main presenting symptoms were pre-syncope in five patients (45.5%) and syncope in three patients (27.3%). Organic cardiovascular diseases were seen in eight patients (72.7%), and AV conduction disturbances were seen in six patients (54.5%), such as right bundle branch block, first to second degree AV block on standard 12-lead electrocardiography. Incidence of PAVB events were 1-329 (37.9±98.0) episodes/patient/day, and the maximum pause during Holter recordings was 3.3-12.4 (6.39±3.09) seconds. This maximum pause caused by intrinsic AV block was longer than that of vagally mediated AV block (8.4±3.2 sec vs 4.7±1.0 sec, p<0.05). In chronobiological analysis, episodes of PAVB exhibited a circadian rhythm characterized by a peak between 2 : 00 am and 4 : 00 am and a trough between 0 : 00 pm and 2 : 00 pm. AECG is a useful tool to detect the maximum pause occurring during sleep and provides critical data necessary to prevent the sudden cardiac death caused by PAVB

Pressure Dependence of Superconductivity in Filled-Skutterudite YOs4P12

We have studied the magnetization on YOs4P12 under pressure up to ∼ 4 GPa. Pure polycrystalline YOs4P12 was prepared by the high-pressure high-temperature method and was evaluated by the X-ray diffraction measurement. YOs4P12 shows superconducting transition at TSC ∼ 3K at ambient pressure. We have investigated the pressure dependence of TSC by means of DC magnetization measurements with incorporating opposed ceramic anvil pressure apparatus into MPMS. TSC of YOs4P12 slightly decreases with pressure at a rate of dTSC/dP = -0.11K/GPa. This is quite contrary to the TSC of related compounds YFe4P12, which rapidly increases with pressure at a rate of 1.0K/GPa. The dTSC/dPs relationship of YFe4P12 and YOs4P12 are similar with that of LaFe4P12 and LaOs4P12. TSC of LaFe4P12 increases rapidly with pressure at a rate of dTSC/dP ∼ 0.72K/GPa below 2GPa and that of LaOs4P12 decreases gradually with pressure at a rate of -0.095K/GPa. Considering these similarity, we can assume that the origin of dTSC/dP of these compounds are the same and are attributed to the density of states at Fermi level and to the Hopfield parameter.Conference : 20th International Conference on Magnetism, ICM 2015Location : Barcelona, SPAINDate : JUL 05-10, 201

Not Even Decoupling Can Save Minimal Supersymmetric SU(5)

We make explicit the statement that Minimal Supersymmetric SU(5) has been excluded by the Super-Kamiokande search for the process $p \to K^{+} \overline{\nu}$. This exclusion is made by first placing limits on the colored Higgs triplet mass, by forcing the gauge couplings to unify. We also show that taking the superpartners of the first two generations to be very heavy in order to avoid flavor changing neutral currents, the so-called ``decoupling'' idea, is insufficient to resurrect the Minimal SUSY SU(5). We comment on various mechanisms to further suppress proton decay in SUSY SU(5). Finally, we address the contributions to proton decay from gauge boson exchange in the Minimal SUSY SU(5) and flipped SU(5) models.Comment: 8 pages, 4 figure

Human induced pluripotent stem cell-derived closed-loop cardiac tissue for drug assessment

Li J., Hua Y., Liu Y., et al. Human induced pluripotent stem cell-derived closed-loop cardiac tissue for drug assessment. iScience 27, 108992 (2024); https://doi.org/10.1016/j.isci.2024.108992.Human iPSC-derived cardiomyocytes (hiPSC-CMs) exhibit functional immaturity, potentially impacting their suitability for assessing drug proarrhythmic potential. We previously devised a traveling wave (TW) system to promote maturation in 3D cardiac tissue. To align with current drug assessment paradigms (CiPA and JiCSA), necessitating a 2D monolayer cardiac tissue, we integrated the TW system with a multi-electrode array. This gave rise to a hiPSC-derived closed-loop cardiac tissue (iCT), enabling spontaneous TW initiation and swift pacing of cardiomyocytes from various cell lines. The TW-paced cardiomyocytes demonstrated heightened sarcomeric and functional maturation, exhibiting enhanced response to isoproterenol. Moreover, these cells showcased diminished sensitivity to verapamil and maintained low arrhythmia rates with ranolazine—two drugs associated with a low risk of torsades de pointes (TdP). Notably, the TW group displayed increased arrhythmia rates with high and intermediate risk TdP drugs (quinidine and pimozide), underscoring the potential utility of this system in drug assessment applications

Efficacy of Mucosal Cutting Biopsy for the Histopathological Diagnosis of Gastric Submucosal Tumors

Background: Gastrointestinal stromal tumors occur frequently. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is performed commonly for diagnosis. However, the success rate of histological diagnosis is insufficient when the submucosal tumor (SMT) is small. Recently, another technique, mucosal cutting biopsy (MCB) has been reported. The aim of this study is to evaluate the efficacy and safety of MCB. Method: Between January 2012 and August 2018, MCB and EUS-FNA were performed 16 and 31 times for diagnosing gastric SMT. The diagnostic rate, the rate of successful immunohistochemistry, and the safety were reviewed. Difficult locations for EUS-FNA were also evaluated. Results: The mean SMT sizes measured on MCB and EUS-FNA were 21.2 and 36.2 mm. The diagnostic rates of MCB and EUS-FNA were almost the same (88 vs. 81%), but successful immunohistochemistry was significantly higher in the MCB group (93 vs. 59%, p = 0.03). In the subgroup of SMTs &#x3c; 20 mm, the successful histological diagnosis rate from EUS-FNA was relatively low. There were no complications. Failures of EUS-FNA were more frequent in the middle third of the stomach. Conclusions: MCB was an effective procedure for diagnosing gastric SMT, especially in the case of small SMTs located at the middle third of the stomach

Displaced Supersymmetry

The apparent absence of light superpartners at the LHC strongly constrains the viability of the MSSM as a solution to the hierarchy problem. These constraints can be significantly alleviated by R-parity violation (RPV). Bilinear R-parity violation, with the single operator L H_u, does not require any special flavor structure and can be naturally embedded in a GUT while avoiding constraints from proton decay (unlike baryon-number-violating RPV). The LSP in this scenario can be naturally long-lived, giving rise to displaced vertices. Many collider searches, particularly those selecting b-jets or leptons, are insensitive to events with such detector-scale displaced decays owing to cuts on track quality and impact parameter. We demonstrate that for decay lengths in the window ~1-1000 mm, constraints on superpartner masses can be as low as ~450 GeV for squarks and ~40 GeV for LSPs. In some parts of parameter space light LSPs can dominate the Higgs decay width, hiding the Higgs from existing searches. This framework motivates collider searches for detector-scale displaced vertices. LHCb may be ideally suited to trigger on such events, while ATLAS and CMS may need to trigger on missing energy in the event.Comment: 35 pages, 4 figure