Loop-TNR analysis of CP(1) model with theta term

The phase structure of the two dimensional lattice CP(1) model in the presence of the $\theta$ term is analyzed by tensor network methods. The tensor renormalization group, which is a standard renormalization method of tensor networks, is used for the regions $\theta =0$ and $\theta \neq 0$. Loop-TNR, which is more suitable for the analysis of near criticality, is also implemented for the region $\theta =0$. The application of Loop-TNR for the region $\theta \neq 0$ is left for future work.Comment: 7 pages, 10 figures, talk presented at the 35th International Symposium on Lattice Field Theory, 18-24 June 2017, Granada, Spai

【第2回山形大学医学部奨励賞受賞論文】Differences Between Squamous Cell Carcinoma and Keratoacanthoma in Angiotensin Type－1 Receptor Expression

　Introduction : Angiotensin II (AngII) of the renin-angiotensin system is the active biological peptide that regulates blood pressure and salt and water homeostasis. AngII exerts its actions by binding the specific receptors. There are two major subtypes of the angiotensin receptors; type 1(AT1) and type 2(AT2). In the human skin, little is known about the expression of the angiotensin receptors. We studied the expression of angiotensin receptors in the normal human skin. Based on the results, we studied the expression of AT1 in squamous cell carcinoma (SCC) and keratoacantoma (KA). It is sometimes difficult to distinguish SCC of the skin from KA because of the histological resemblance of these tumors. At present, few methods enable it possible to distinguish SCC from KA. Our experiments revealed differences between SCC and KA in AT1 expression.　Materials and Methods : A total of fifty cases of SCC of the skin and fourteen cases of SCC of the lip were selected from a consecutive series of sixty-nine cases diagnosed and treated for SCC at Yamagata University Hospital, Japan between 1978-1999. All twenty-two cases that were diagnosed and treated for KA at the hospital between 1978-1999 were also studied. Normal back skin from a 38-year-old Japanese woman, normal lip from a 64-year-old Japanese man, and normal brain tissue from a 33-year-old man were used as normal controls. Five-μm-thick paraffin-embedded tissue sections were offered for hematoxylin and eosin stain and immunohistochemical study using the labeled streptavidin-biotin method. The primary antibodies used in this study were anti-angiotensin type-1 and type-2 receptor antibodies.　In cases of SCC of the skin, SCC of the lip, and KA, the percentage of AT1-positive tumor cells of all neoplastic cells in the section was estimated and graded into one of three categories: low (75%). Among the cases that were graded high, there was a group of cases that showed a distinct staining pattern.In this pattern, 1 to 2 layers of the tumor cells that were located at the periphery of the tumor nest stained negatively. This pattern was termed as negative periphery and was graded as one category independent of the other three categories that showed no particular arrangement of AT1-positive cells.　Results : In the interfollicular epidermis of normal human skin, the suprabasal epidermis stained positive with AT1, but the basal layer was negative. As to the infundibulum of the hair follicle, the suprabasal layers of the outer root sheath were all positive. The basal layer of the outer root sheath was negative. In the vermilion border of normal lip, unlike the normal epidermis, the upper two to three layers of the epithelium stained positive with AT1, but the other layers of the epithelium including the basal layer were negative. In SCC of the skin, high, intermediate, and low levels of AT1 were observed in thirty-seven (74.0%), seven (14.0%), and two cases (4.0%), respectively. Four cases (8.0%) showed negative periphery pattern. In KA, seventeen cases (77.3%) showed a negative periphery pattern. In SCC of the lip, high, intermediate, and low levels of AT1 were observed in three (21.4%), three (21.4%), and six cases (42.9%), respectively. Two cases (14.3%) showed a negative periphery pattern. All specimens were negative with anti-AT2 antibody.　Discussion : Immunohistochemical study domonstrated the expression of AT1 in the normal human skin and the skin tumors. SCC of the skin is generally believed to originate from the normal squamous cells which are located in the suprabasal epidermis. In SCC, 74.0% of the cases were graded as high. This result seem to reflect the belief of suprabasal origin of SCC. On the other hand, KA, which is a benign skin tumor, often resembles well- or moderately differentiated SCC clinically and histologically. In some cases, KA shows a greater degree of nuclear atypia than do some SCCs, and this makes the differentiation of two diseases very difficult. It is generally believed that KA has its origin in the infundibulum of one or several hair follicles. In KA, 77.3% of the cases were graded as negative periphery. This result seem to reflect the infundibular origin of KA. The results of immunostaining of SCC and KA demonstrated a striking contrast. Our study indicate that immunohistochemical study of the expression of AT1 assists one to distinguish SCC from KA. In SCC of the lip, the percentage of AT1-positive cells of the tumor cells is low compared to that SCC of the skin and this result may reflect less immunoreactivity with AT1 of the normal lip epithelium. These observations suggest that the immunohistochemical study of AT1 is useful to distinguish SCC from KA. Studying the role and distribution of AT1 may help in understanding the pathophysiology of the skin

Non-LTE Line-Formation and Abundances of Sulfur and Zinc in F, G, and K Stars

Extensive statistical-equilibrium calculations on neutral sulfur and zinc were carried out, in order to investigate how the non-LTE effect plays a role in the determination of S and Zn abundances in F, G, and K stars. Having checked on the spectra of representative F-type stars (Polaris, Procyon, and alpha Per) and the Sun that our non-LTE corrections yield a reasonable consistency between the abundances derived from different lines, we tried an extensive non-LTE reanalysis of published equivalent-width data of S I and Zn I lines for metal-poor halo/disk stars. According to our calculations, S I 9212/9228/9237 lines suffer significant negative non-LTE corrections amounting to <~ 0.2--0.3 dex, while LTE is practically valid for S I 8683/8694 lines. Embarrassingly, as far as the very metal-poor regime is concerned, a marked discordance is observed between the [S/Fe] values from these two abundance indicators, in the sense that the former attains a nearly flat plateau (or even a slight downward bending) while the latter shows an ever-increasing trend with a further lowering of metallicity. The reason for this discrepancy is yet to be clarified. Regarding Zn, we almost confirmed the characteristic tendencies of [Zn/Fe] reported from recent LTE studies (i.e., an evident/slight increase of [Zn/Fe] with a decrease of [Fe/H] for very metal-poor/disk stars), since the non-LTE corrections for the Zn I 4722/4810 and 6362 lines (tending to be positive and gradually increasing towards lower [Fe/H]) are quantitatively of less significance (<~ 0.1 dex).Comment: 33 pages, 7 figures, PASJ, Vol. 57, No. 5 (2005) in pres

Flame Stabilisation Mechanism for Under-Expanded Hydrogen Jets

A hydrogen under-expanded jet released from a high-pressure vessel or equipment into the atmosphere through a 0.53 mm diameter orifice results in a sustained lifted flame for pressures above 4 MPa and flame blow-out at pressures below 3 MPa. Knowledge of whether the leaked hydrogen creates a sustained flame or is extinguished is an important issue for safety engineering. This study aims to clarify, in detail, a mechanism of flame stabilisation and blow-out depending on the spouting pressure. The model of flame stabilisation is derived using measurements and observations at the flame base location by means of high-speed schlieren images, laser diagnostics, and electrostatic probe techniques. The sustained stable flame originating from the 0.53 mm orifice is characterised by the existence of the spherical flame structures with a diameter of about 5 to 7 mm that appear one after another at the flame base and outside the streamlines of the hydrogen jet. As the spouting pressure reduces to 3.5 MPa, the sustained lifted flame becomes quasi-steady with higher fluctuations in amplitude of the flame base (lift-off height). In addition to that, flame structures are moving further from the hydrogen jet outlet, with a further decrease of spouting pressure leading to blow-out. The existence of spherical flame formations plays an important role in flame stabilisation. Based on the measurements of OH radicals using the PLIF method and ion currents, multiple flame surfaces were found to be folded in the flame structures. The hydrogen jet generates the vortex-like flow near its outer edge, creating flamelets upon ignition, ultimately forming the observed in the experiments spherical flame structures

Topological Thermal Hall Effect Induced by Magnetic Skyrmions

Quantized transports of fermions are topological phenomena determined by the sum of the Chern numbers of all the energy bands below the Fermi energy. For bosonic excitations, e.g. phonons and magnons in a crystal, topological transport is dominated by the Chern number of the lowest energy band because the energy distribution of the bosons is limited below the thermal energy. Here, we demonstrate the existence of topological transport by bosonic magnons in a lattice of magnetic skyrmions - topological defects formed by a vortex-like texture of spins. We find a distinct thermal Hall signal when the ferromagnetic spins in an insulating polar magnet GaV4Se8 form magnetic skyrmions. Its origin is identified as the topological thermal Hall effect of magnons in which the trajectories of these magnons are bent by an emergent magnetic field produced by the magnetic skyrmions. Our theoretical simulations confirm that the thermal Hall effect is indeed governed by the Chern number of the lowest energy band of the magnons in a triangular lattice of magnetic skyrmions. Our findings lay a foundation for studying topological phenomena of other bosonic excitations.Comment: 13 pages, 3 figures, and Supplementary Informatio