Orbital evolution of Saturn's satellites due to the interaction between the moons and massive Saturn's rings

Saturn's mid-sized moons (satellites) have a puzzling orbital configuration with trapping in mean-motion resonances with every other pairs (Mimas-Tethys 4:2 and Enceladus-Dione 2:1). To reproduce their current orbital configuration on the basis of Crida & Charnoz's model of satellite formation from a hypothetical ancient massive rings, adjacent pairs must pass 1st-order mean-motion resonances without being trapped. The trapping could be avoided by fast orbital migration and/or excitation of the satellite's eccentricity caused by gravitational interactions between the satellites and the rings (the disk), which are still unknown. In our research, we investigate the satellite orbital evolution due to interactions with the disk through full N-body simulations. We performed global high-resolution N-body simulations of a self-gravitating particle disk interacting with a single satellite. We used $N \sim 10^5$ particles for the disk. Gravitational forces of all the particles and their inelastic collisions are taken into account. As a result, dense short-wavelength wake structure is created by the disk self-gravity and global spiral arms with $m \sim$ a few is induced by the satellite. The self-gravity wakes regulate the orbital evolution of the satellite, which has been considered as a disk spreading mechanism but not as a driver for the orbital evolution. The self-gravity wake torque to the satellite is so effective that the satellite migration is much faster than that was predicted with the spiral arms torque. It provides a possible model to avoid the resonance capture of adjacent satellite pairs and establish the current orbital configuration of Saturn's mid-sized satellites.Comment: (6 pages, 4 figures, Accepted in A&A

Gradient Flow Decoding for LDPC Codes

The power consumption of the integrated circuit is becoming a significant burden, particularly for large-scale signal processing tasks requiring high throughput. The decoding process of LDPC codes is such a heavy signal processing task that demands power efficiency and higher decoding throughput. A promising approach to reducing both power and latency of a decoding process is to use an analog circuit instead of a digital circuit. This paper investigates a continuous-time gradient flow-based approach for decoding LDPC codes, which employs a potential energy function similar to the objective function used in the gradient descent bit flipping (GDBF) algorithm. We experimentally demonstrate that the decoding performance of the gradient flow decoding is comparable to that of the multi-bit mode GDBF algorithm. Since an analog circuit of the gradient flow decoding requires only analog arithmetic operations and an integrator, future advancements in programmable analog integrated circuits may make practical implementation feasible.Comment: 6 page

Stability and Solubility of the FeAlO3 Component in Bridgmanite at Uppermost Lower Mantle Conditions

We report the stability and solubility of the FeAlO3 component in bridgmanite based on phase relations in the system MgSiO3-FeAlO3 at 27 GPa and 2000 K using a multi-anvil apparatus combined with in situ synchrotron X-ray diffraction measurements. The results demonstrate that the FeAlO3 component dominates Fe3+ and Al3+ substitution in bridgmanite, although trace amounts of oxygen- and Mg-site vacancy components are also present. Bridgmanite with more than 40 mol% FeAlO3 transforms into the LiNbO3-type phase upon decompression. The FeAlO3 end-member decomposes into corundum and hematite and does not form single-phase bridgmanite. We determined the maximum solubility of the FeAlO3 component in bridgmanite at 27 GPa and 2000 K to be 67 mol%, which is significantly higher than previously reported values (25–36 mol%). We determined the partial molar volume (27.9 mol/cm3) and bulk modulus (197 GPa) of hypothetical FeAlO3 bridgmanite, which are significantly higher and lower than those of AlAlO3 and FeSiO3 bridgmanite, respectively. The non-ideality of MgSiO3-FeAlO3 solid solution (W = 13 kJ/mol, where W is the interaction parameter) is significantly larger than that for MgSiO3-AlAlO3 (5 kJ/mol) and MgSiO3-FeSiO3 (3 kJ/mol) solid solutions. The rapid decrease in abundance of the MgAlO2.5 component in bridgmanite with increasing pressure is enhanced by the presence of the FeAlO3 component. The FeAlO3 content in pyrolite and mid-ocean ridge basalt is far below its solubility limit in bridgmanite and provides new insight into the mineralogy of the lower mantle

Is Estrogen Effective for Full-Thickness Cutaneous Wound Healing in Young Male Mice ?

The aim of this study is to show the effects of estrogen upon its topical application on the wound healing process in young male mice. Fifty-six male mice aged 7 weeks old were divided into 4 groups: sham operation, castration, estrogen treatment after sham operation, and estrogen treatment after castration. Wound healing was observed daily until day 14 after wounding. Specimens were harvested on days 3, 7, 10, and 14, and stained to evaluate reepithelialization, inflammation, contraction, and collagen accumulation. Wound healing periods of all groups were almost the same, although the concentration of serum estrogen in the estrogen-applied mice was very high, and that in the nonapplied groups was low. The numbers of macrophages in the castrated, estrogen-treated after sham operation, and estrogen-treated after castration groups were significantly decreased compared with that in the sham group in the inflammatory phase; however, the ratio of wound area in these groups did not decrease, and other histological data did not reveal any effects of estrogen. These results indicate that estrogen may show limited effectiveness for full-thickness cutaneous wound healing in young male mice, and decreased inflammation may not always be associated with decreased wound area

Effect of context exposure after fear learning on memory generalization in mice

BackgroundThe conditions under which memory generalization occurs are not well understood. Although it is believed that fear memory generalization is gradually established after learning, it is not clear whether experiences soon after learning affect generalization.ResultsUsing a contextual fear conditioning paradigm in mice, we found that fear memory generalization occurred when mice were exposed to a familiar, unconditioned context soon after fear learning.ConclusionsOur results suggest that the familiarity of contexts and the timing of their exposure influences memory generalization, which increases our understanding of the mechanisms of generalization

Potential Association between Breakfast Skipping and Concomitant Late-Night-Dinner Eating with Metabolic Syndrome and Proteinuria in the Japanese Population

Skipping breakfast is considered to be an unhealthy eating habit linked to predispositions to obesity and type 2 diabetes. Because eating dinner late at night can elicit subsequent breakfast skipping, we investigated if skipping breakfast concomitant with late-night-dinner eating (LNDE) was associated with metabolic syndrome (MetS) and proteinuria in the general Japanese population. We examined self-reported habitual breakfast skipping and LNDE, MetS (modified ATP-III criteria), and proteinuria in a cross-sectional study of 60,800 Japanese adults aged 20–75 years. A total of 14,068 subjects (23.1%) skipped breakfast, of whom approximately half (52.8%) skipped breakfast alone (without LNDE). The percentages of subjects who skipped breakfast showed a J-shaped relationship with body mass index (BMI). Multivariate logistic regression analysis showed that skipping breakfast concomitant with LNDE (n = 6,645) was significantly associated with MetS and proteinuria, even after adjusting for relevant confounders (odds ratio (95% CI), 1.17 (1.08–1.28), P=0.0003, and 1.37 (1.24–1.52), P<0.0001, resp.). Skipping breakfast alone and LNDE alone were not associated with MetS and proteinuria, respectively. In conclusion, habitual breakfast skipping concomitant with LNDE may represent poorer eating behavior than skipping breakfast alone, associated with MetS, asymptomatic proteinuria, obesity, and low body weight in the general Japanese population

Evaluation of a pregnancy programme to enhance older primiparas' physical and mental health and marital relationships after childbirth: A non‐randomized clinical trial

Abstract Aim This study evaluated a pregnancy programme designed by us to stabilize older primiparas' physical and mental health and strengthen their marital relationships. Design A non‐randomized controlled trial study of two groups; an intervention and control group. Methods Ultimately the scores of 15 participants assigned to an intervention group and 15 assigned to a control group were analysed. Participants responded to sociodemographic questions, the Edinburgh Postnatal Depression Scale (EPDS), a postpartum physical fatigue questionnaire, wives' satisfaction with husbands' support questionnaire and Quality Marriage Index (QMI). Data were collected during pregnancy and at one and 3 months after childbirth. Results The participating wives' EPDS scales significantly decreased after the postpartum course in the intervention group. Participating in the programme significantly raised husbands' awareness of their wives' physical burdens 1 month after childbirth. The subscale ‘housework support/wives' satisfaction with husbands' support’, 3 months after childbirth, did not decline. It is suggested that this programme could strengthen marital relationships because the husbands' understanding of their spouses' physical burdens after childbirth led to an improvement in the wives' satisfaction with their spouses' housework support. Participation in the pregnancy programme may strengthen the marital relationship. This study recommends appropriate nursing support for pregnant couples to improve their physical and mental health