Supersymmetry Enhancement and Junctions in S-folds

We study supersymmetry enhancement from ${\cal N}=3$ to ${\cal N}=4$ proposed by Aharony and Tachikawa by using string junctions in S-folds. The central charges carried by junctions play a central role in our analysis. We consider planer junctions in a specific plane. Before the S-folding they carry two complex central charges, which we denote by $Z$ and $\bar Z$. The S-fold projection eliminates $\bar Z$ as well as one of the four supercharges, and when the supersymmetry is enhanced $\bar Z$ should be reproduced by some non-perturbative mechanism. For the models of $\mathbb{Z}_3$ and $\mathbb{Z}_4$ S-folds which are expected to give $SU(3)$ and $SO(5)$ ${\cal N}=4$ theories we compare the junction spectra with those in perturbative brane realization of the same theories. We establish one-to-one correspondence so that $Z$ coincides. By using the correspondence we also give an expression for the enhanced central charge $\bar Z$.Comment: 30 pages, 7 figures, v2: minor corrections, version accepted for publication in JHE

Sliding wear of nitrided steels

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The unlubricated sliding wear behaviour of gas nitrided, plasma nitrided, and ferritic nitrocarburized BS970,905M39 (EN41B) steels was investigated systematically from an engineering point of view. Commercial nitriding processes were employed, and the wear studies were carried out using a pin-on-disc machine over a wide range of sliding speeds and applied loads. The worn specimens and wear debris were examined by several techniques; including optical and electron microscopy and X-ray analysis. A sharp wear rate transition between mild and severe regimes was identified by varying the load for both untreated and gas nitrided steels. The wear rate was reduced by gas nitriding by up to two orders of magnitude, depending on the sliding condition. Moreover, gas nitriding expanded the mild wear region toward higher loads and sliding speeds. In the mild regime an oxidative wear mechanism operated, contrasting with the metallic wear in the severe regime. Wear maps for untreated and gas nitrided steels have been constructed, which show the dominant regimes of the wear mechanisms. A "wear-face-limited" gas nitrided pin test showed that the benefit of the treatment was lost once the effective surface layer was completely worn away. It is suggested that hardness has a crucial role in determining the wear rate through nitrided diffusion layers. A thick and porous compound layer produced by gas nitriding showed a poor wear behaviour owing to its brittleness, while a thin nitrocarburized E-Fe3N compound layer exhibited a low wear rate. There was no significant difference between the nitride steels in terms of transition load and wear rate. However, the wear lives of the nitrided layers were dependent on their case depth. Severe wear should be avoided in engineering component design, and operating conditions should ensure that only mild wear occurs. Both the hardness profiles and the cost performance of nitriding processes should be considered in the selection of nitriding treatments.Financial support was obtained from Komatsu Ltd

A Qualitative Exploration to Understand Hospitalists’ Attitude toward the Patient Experience Scoring System

Patient’s perception of their inpatient experience is measured by the Center for Medical Services’ (CMS) administered Hospital Consumer Assessment of Healthcare Providers & Systems (HCAHPS) survey. There is scant existing literature on physicians’ perceptions toward the HCAHPS scoring system. Understanding hospitalist knowledge and attitude toward the HCAHPS survey can help guide efforts to impact HCAHPS survey scores by improving the patient’s perception of their hospital experience. The goal of this study is to explore hospitalists’ knowledge and perspective of the physician communication domain of the HCAHPS survey at an academic medical center. Seven hospitalists at an academic medical center were interviewed for this report using a semistructured interview. Thematic analysis approach was used to analyze data. Open, line-by-line coding was performed on all 7 transcripts. Categories were derived in an inductive fashion. Categories were refined using the techniques of constant comparison and axial coding. We generated themes reflecting hospitalists’ knowledge of the HCAHPS scoring system, their perception of the HCAHPS scoring system and the impact of the HCAHPS scoring system on their practice. While hospitalists acknowledged physician–patient communication is a challenging area to study, they are unlikely to embrace the feedback provided by HCAHPS surveys. There is a need to deploy tactics that provide timely and actionable feedback to providers on their bedside communication skills

Evolution of nuclear auxin signaling : Lessons from genetic studies with basal land plants

Auxin plays critical roles in growth and development through the regulation of cell differentiation, cell expansion, and pattern formation. The auxin signal is mainly conveyed through a so-called nuclear auxin pathway involving the receptor TIR1/AFB, the transcriptional co-repressor AUX/IAA, and the transcription factor ARF with direct DNA-binding ability. Recent progress in sequence information and molecular genetics in basal plants has provided many insights into the evolutionary origin of the nuclear auxin pathway and its pleiotropic roles in land plant development. In this review, we summarize the latest knowledge of the nuclear auxin pathway gained from studies using basal plants, including charophycean green algae and two major model bryophytes, Marchantia polymorpha and Physcomitrella patens. In addition, we discuss the functional implication of the increase in genetic complexity of the nuclear auxin pathway during land plant evolution

Auxin signaling is essential for organogenesis but not for cell survival in the liverwort Marchantia polymorpha

ゼニゴケを用いて植物ホルモンの役割を証明 --オーキシン信号伝達なくして器官形成なし--. 京都大学プレスリリース. 2023-02-07.Auxin plays pleiotropic roles in plant development via gene regulation upon its perception by the receptors TRANSPORT INHIBITOR RESPONSE 1/AUXIN SIGNALING F-BOX (TIR1/AFBs). This auxin-regulated transcriptional control mechanism originated in the common ancestor of land plants. Although the complete loss of TIR1/AFBs causes embryonic lethality in Arabidopsis thaliana, it is unclear whether the requirement for TIR1-mediated auxin perception in cell viability can be generalized. The model liverwort Marchantia polymorpha has a minimal auxin signaling system with only a single TIR1/AFB, MpTIR1. Here we show by genetic, biochemical, and transcriptomic analyses that MpTIR1 functions as an evolutionarily conserved auxin receptor. Null mutants and conditionally knocked-out mutants of MpTIR1 were viable but incapable of forming any organs and grew as cell masses. Principal component analysis performed using transcriptomes at various developmental stages indicated that MpTIR1 is involved in the developmental transition from spores to organized thalli, during which apical notches containing stem cells are established. In Mptir1 cells, stem cell- and differentiation-related genes were up- and downregulated, respectively. Our findings suggest that, in M. polymorpha, auxin signaling is dispensable for cell division but is essential for three-dimensional patterning of the plant body by establishing pluripotent stem cells for organogenesis, a derived trait of land plants

High-fidelity conversion of photonic quantum information to telecommunication wavelength with superconducting single-photon detectors

We experimentally demonstrate a high-fidelity visible-to-telecommunication wavelength conversion of a photon by using a solid-state-based difference frequency generation. In the experiment, one half of a pico-second visible entangled photon pair at 780 nm is converted to a 1522-nm photon, resulting in the entangled photon pair between 780 nm and 1522 nm. Using superconducting single-photon detectors with low dark count rates and small timing jitters, we selectively observed well-defined temporal modes containing the two photons. We achieved a fidelity of $0.93 \pm 0.04$ after the wavelength conversion, indicating that our solid-state-based scheme can be used for faithful frequency down-conversion of visible photons emitted from quantum memories composed of various media.Comment: 5 pages, 4 figure