Self-organization on social media: endo-exo bursts and baseline fluctuations

A salient dynamic property of social media is bursting behavior. In this paper, we study bursting behavior in terms of the temporal relation between a preceding baseline fluctuation and the successive burst response using a frequency time series of 3,000 keywords on Twitter. We found that there is a fluctuation threshold up to which the burst size increases as the fluctuation increases and that above the threshold, there appears a variety of burst sizes. We call this threshold the critical threshold. Investigating this threshold in relation to endogenous bursts and exogenous bursts based on peak ratio and burst size reveals that the bursts below this threshold are endogenously caused and above this threshold, exogenous bursts emerge. Analysis of the 3,000 keywords shows that all the nouns have both endogenous and exogenous origins of bursts and that each keyword has a critical threshold in the baseline fluctuation value to distinguish between the two. Having a threshold for an input value for activating the system implies that Twitter is an excitable medium. These findings are useful for characterizing how excitable a keyword is on Twitter and could be used, for example, to predict the response to particular information on social media.Comment: Presented at WebAL-1: Workshop on Artificial Life and the Web 2014 (arXiv:1406.2507

Mechanisms Underlying the Comorbidity of Schizophrenia and Type 2 Diabetes Mellitus

The mortality rate of patients with schizophrenia is high, and life expectancy is shorter by 10 to 20 years. Metabolic abnormalities including type 2 diabetes mellitus (T2DM) are among the main reasons. The prevalence of T2DM in patients with schizophrenia may be epidemiologically frequent because antipsychotics induce weight gain as a side effect and the cognitive dysfunction of patients with schizophrenia relates to a disordered lifestyle, poor diet, and low socioeconomic status. Apart from these common risk factors and risk factors unique to schizophrenia, accumulating evidence suggests the existence of common susceptibility genes between schizophrenia and T2DM. Functional proteins translated from common genetic susceptibility genes are known to regulate neuronal development in the brain and insulin in the pancreas through several common cascades. In this review, we discuss common susceptibility genes, functional cascades, and the relationship between schizophrenia and T2DM. Many genetic and epidemiological studies have reliably associated the comorbidity of schizophrenia and T2DM, and it is probably safe to think that common cascades and mechanisms suspected from common genes' functions are related to the onset of both schizophrenia and T2DM. On the other hand, even when genetic analyses are performed on a relatively large number of comorbid patients, the results are sometimes inconsistent, and susceptibility genes may carry only a low or moderate risk. We anticipate future directions in this field

Effects of acute aerobic exercise on arterial stiffness in transgender men

Testosterone replacement therapy (TRT) in transgender men (TM) results in side effects such as elevated triglycerides and increased arterial stiffness. Exercise may be useful to ameliorate such effects, but no studies have examined the effects of acute aerobic exercise in TM. This study aimed to investigate the effects of acute aerobic exercise on arterial stiffness in TM. Thirty-six participants were included, comprising 12 TM (duration of TRT: 57.4 ± 30.3 months), 12 males and 12 females. All participants performed acute aerobic exercise on a treadmill at 50% heart rate reserve for 30 min. Arterial stiffness as measured by brachial-ankle pulse wave velocity (baPWV) was measured before exercise (Pre), 30 min after exercise (Post30), and 60 min after exercise (Post60). Serum sex hormone levels, and serum lipid profile were determined only before exercise. Serum low-density lipoprotein cholesterol (LDL-C) levels before exercise were significantly higher in TM than in males or females (males: p < 0.01; females: p < 0.05). At all points, baPWV in TM was significantly higher than in females (p < 0.05) and significantly lower than in males (p < 0.05). However, when comparing changes in baPWV over time in each group, significant decreases in Post30 and Post60 were seen in males compared to Pre (both p < 0.05), but no significant change after aerobic exercise was seen in TM or females. These results suggest that acute aerobic exercise yield different effects in TM than in males, but is unlikely to reduce arterial stiffness in TM receiving TRT

Pathogenic Roles of Cardiac Fibroblasts in Pediatric Dilated Cardiomyopathy

BACKGROUND: Dilated cardiomyopathy (DCM) is a major cause of heart failure in children. Despite intensive genetic analyses, pathogenic gene variants have not been identified in most patients with DCM, which suggests that cardiomyocytes are not solely responsible for DCM. Cardiac fibroblasts (CFs) are the most abundant cell type in the heart. They have several roles in maintaining cardiac function; however, the pathological role of CFs in DCM remains unknown. METHODS AND RESULTS: Four primary cultured CF cell lines were established from pediatric patients with DCM and compared with 3 CF lines from healthy controls. There were no significant differences in cellular proliferation, adhesion, migration, ap-optosis, or myofibroblast activation between DCM CFs compared with healthy CFs. Atomic force microscopy revealed that cellular stiffness, fluidity, and viscosity were not significantly changed in DCM CFs. However, when DCM CFs were cocultured with healthy cardiomyocytes, they deteriorated the contractile and diastolic functions of cardiomyocytes. RNA sequencing revealed markedly different comprehensive gene expression profiles in DCM CFs compared with healthy CFs. Several hu-moral factors and the extracellular matrix were significantly upregulated or downregulated in DCM CFs. The pathway analysis revealed that extracellular matrix receptor interactions, focal adhesion signaling, Hippo signaling, and transforming growth factor-β signaling pathways were significantly affected in DCM CFs. In contrast, single-cell RNA sequencing revealed that there was no specific subpopulation in the DCM CFs that contributed to the alterations in gene expression. CONCLUSIONS: Although cellular physiological behavior was not altered in DCM CFs, they deteriorated the contractile and diastolic functions of healthy cardiomyocytes through humoral factors and direct cell–cell contact.Tsuru H., Yoshihara C., Suginobe H., et al. Pathogenic Roles of Cardiac Fibroblasts in Pediatric Dilated Cardiomyopathy. Journal of the American Heart Association 12, e029676 (2023); https://doi.org/10.1161/JAHA.123.029676

Orbital characterization of GJ1108A system, and comparison of dynamical mass with model-derived mass for resolved binaries

We report an orbital characterization of GJ1108Aab that is a low-mass binary system in pre-main-sequence phase. Via the combination of astrometry using adaptive optics and radial velocity measurements, an eccentric orbital solution of $e$=0.63 is obtained, which might be induced by the Kozai-Lidov mechanism with a widely separated GJ1108B system. Combined with several observed properties, we confirm the system is indeed young. Columba is the most probable moving group, to which the GJ1108A system belongs, although its membership to the group has not been established. If the age of Columba is assumed for GJ1108A, the dynamical masses of both GJ1108Aa and GJ1108Ab ($M_{\rm dynamical,GJ1108Aa}=0.72\pm0.04 M_{\odot}$ and $M_{\rm dynamical,GJ1108Ab}=0.30\pm0.03 M_{\odot}$) are more massive than what an evolutionary model predicts based on the age and luminosities. We consider the discrepancy in mass comparison can attribute to an age uncertainty; the system is likely older than stars in Columba, and effects that are not implemented in classical models such as accretion history and magnetic activity are not preferred to explain the mass discrepancy. We also discuss the performance of the evolutionary model by compiling similar low-mass objects in evolutionary state based on the literature. Consequently, it is suggested that the current model on average reproduces the mass of resolved low-mass binaries without any significant offsets.Comment: Accepted in Ap

センダイシ オヨビ ナトリシ デ シハンサレル トリ ヒキニク カラノ サルモネラ ノ ケンシュツ ホウコク

本研究では、宮城県で調査報告の少ない鳥ひき肉におけるサルモネラの汚染状況を調査した。その結果、市販される鶏ひき肉55.2％にサルモネラの汚染が確認された。この汚染レベルは、全国レベルに匹敵し、鶏の育成場所や鳥肉処理場、ミンチ加工処理、包装などが違えども、同程度の汚染がみられた。またムネ肉とモモ肉では、汚染には差が認められなかった。販売店舗としては調査した11店舗中10店舗の鳥ひき肉でサルモネラ汚染は認められたが、直接培養で検出されないなど、その汚染菌数は少ない。さらに冷蔵や加熱などの食品に認められる損傷菌に関しても、今回分離したサルモネラの37.5％が損傷菌である可能性がある。ここ宮城県仙台市および名取市で市販される鳥ひき肉からもサルモネラ菌の汚染が示されたことから、鳥ひき肉の調理や取り扱いにも十分注意することを強調したい