On Ratliff-Rush closure of modules

In this paper, we introduce the notion of Ratliff-Rush closure of modules and explore whether the condition of the Ratliff-Rush closure coincides with the integral closure. The main result characterizes the condition in terms of the normality of the projective scheme of the Rees algebra, which generalizes the result of S. Goto and N. Matsuoka. In conclusion, we shall give a criterion for the Buchsbaum Rees algebras.Comment: 15 page

Remarks on almost Gorenstein rings

This paper investigates the relation between the almost Gorenstein properties for graded rings and for local rings. Once $R$ is an almost Gorenstein graded ring, the localization $R_M$ of $R$ at the graded maximal ideal $M$ is almost Gorenstein as a local ring. The converse does not hold true in general. However, it does for one-dimensional graded domains with mild conditions, which we clarify in the present paper. We explore the defining ideals of almost Gorenstein numerical semigroup rings as well.Comment: 9 page

Boosting Spectral Efficiency with Data-Carrying Reference Signals on the Grassmann Manifold

In wireless networks, frequent reference signal transmission for accurate channel reconstruction may reduce spectral efficiency. To address this issue, we consider to use a data-carrying reference signal (DC-RS) that can simultaneously estimate channel coefficients and transmit data symbols. Here, symbols on the Grassmann manifold are exploited to carry additional data and to assist in channel estimation. Unlike conventional studies, we analyze the channel estimation errors induced by DC-RS and propose an optimization method that improves the channel estimation accuracy without performance penalty. Then, we derive the achievable rate of noncoherent Grassmann constellation assuming discrete inputs in multi-antenna scenarios, as well as that of coherent signaling assuming channel estimation errors modeled by the Gauss-Markov uncertainty. These derivations enable performance evaluation when introducing DC-RS, and suggest excellent potential for boosting spectral efficiency, where interesting crossings with the non-data carrying RS occurred at intermediate signal-to-noise ratios.Comment: 13 pages, 10 figure

Bone Histomorphometry of Femoral Head Cancellous Bone in Patients Who Underwent Total Hip Arthroplasties due to Destructive Hip in Rheumatoid Arthritis

Rheumatoid arthritis (RA) affects the hip joints. The microarchitecture of the cancellous bone in RA-affected hip joints has been unclear. Here we investigated the bone metabolism changes in the subcapital cancellous bone of destructive hips of RA patients (n=26 patients; 28 hip joints) which were classified by Larsen grade on X-ray into the groups: destructive hip (Des) (Larsen grade IV, n=18) and neck fracture (Fx) (Larsen grade 0 or 1, n=10). The femoral heads of the Des-group showed significantly higher trabecular thickness versus those of the Fx-group (179±30.8 vs. 151±23.5 μm, p=0.02). The Des-group had significantly higher osteoid volume/tissue volume (OV/TV) and osteoid volume/bone volume (OV/BV) ratios than the Fx-group (OV/TV: 0.72±0.70% vs. 0.27±0.32%, p=0.028; OV/BV: 2.96±2.85% vs. 1.24±1.31%, p=0.039). The osteoblast and osteoclast surface areas of the Des-group were remarkably higher than those of the Fx-group (9.80±10.9 vs. 0.15±0.15%, p=0.0005; 0.34±0.48 vs. 0.06±0.06%, p=0.0285, respectively). The T-scores of hip (femoral neck) bone mineral density (BMD) of the Fx-group were significantly lower versus those of the Des-group (−3.1±0.76 vs. −1.6±1.17, p<0.01). Increased osteoid and resorption parameters and higher femoral neck BMD demonstrate a high bone-turnover state in response to destructive changes in the hips of RA patients

Phylogenetic analyses of Japanese golden chanterelles and a new species description, Cantharellus anzutake sp nov.

ArticleMycoscience. 59(2): 153-165. (2018)journal articl

Preliminary study of discrimination of human vocal commands in walrus (Odobenus rosmarus divergens)

Walruses seem to use various acoustic signals in social context. So, the auditory faculty is seems to be important for walruses. Can walruses understand another animals' vocal information using auditory sense? This study tested whether a male walrus could discriminate human vocal words and perform different actions corresponding to each one under various conditions. The subject, a male walrus (Odobenus rosmarus) named Pou, was set on the ground, and the experimenter spoke one of the ten words to the subject under the following conditions; (1) The experimenter stood close to the subject and spoke each vocal stimulus wearing a black cloak and goggles so that the experimenter's eye and body movements would not influence the subject's behavior, (2) A wooden board was placed between the experimenter and the subject so that the subject could not see the experimenter, (3) A wooden board was placed between the experimenter and the subject so that the subject could not to see the experimenter, and the experimenter uttered each vocal stimulus through an audio speaker. Under each condition, when the subject performed the correct action corresponding to the vocal stimulus, he was rewarded with a piece of fish. As a result, the subject responded correctly to almost all the human vocal stimuli in every condition, including when the speaker was not visible. This means that he was indeed responding to the vocal words and not the experimenter's cues. This study demonstrated that walruses can hear and identify human vocal words using their auditory sense and can form correspondence between vocal words and their meanings