The spatiotemporal cohesion of a group is an essential element of primate society. It is thus important to clarify the factors that influence the extent of variation in spatial cohesion and ...individual membership in a group over time, known as fission–fusion dynamics. During the mating season of 2019, the alpha male (
TY)
in a wild group of Japanese macaques on Kinkazan Island repeatedly disappeared from the group, and we observed fission–fusion dynamics caused by his movement. The group seemed to have split when
TY
left the group or its home range, and females who followed him had the most affiliative relationships with
TY
or were the relatives of those females. Although
TY
disappeared from the group in the post-mating season, these fission–fusion dynamics only occurred during the mating season probably because females had a more substantial need for protection against aggression from the other males during the mating season. These results indicate that, although rare, fission–fusion dynamics based on affiliative relationships between males and females can occur with the separation of alpha males from the group. More studies in other populations are needed to clarify the influence of group males on the spatial cohesion of groups.
Precipitation is thought to be a necessary but insufficient condition for the transformation of stratocumulus-topped closed cellular convection to open cellular cumuliform convection. Here we test ...the hypothesis that the spatial distribution of precipitation is a key element of the closed-to-open cell transition. A series of idealized 3-D simulations are conducted to evaluate the dependency of the transformation on the areal coverage of rain, and to explore the role of interactions between multiple rainy areas in the formation of the open cells. When rain is restricted to a small area, even substantial rain (order few mm day-1) does not result in a transition. With increasing areal coverage of the rain, the transition becomes possible provided that the rain rate is sufficiently large. When multiple small rain regions interact with each other, the transition occurs and spreads over a wider area, provided that the distance between the rain regions is short. When the distance between the rain areas is large, the transition eventually occurs, albeit slowly. For much longer distances between rain regions the system is anticipated to remain in a closed-cell state. These results suggest a connection to the recently hypothesized remote control of open-cell formation. Finally it is shown that this transition occurs along a consistent path in the phase space of the mean vs. coefficient of variation of the liquid water path, droplet number and optical depth. This could be used as a diagnostic tool for global analyses of the statistics of closed- and open-cell occurrence and transitions between them.
Regulatory T cells (Tregs), either natural or induced, suppress a variety of physiological and pathological immune responses. One of the key issues for understanding Treg function is to determine how ...they suppress other lymphocytes at the molecular level in vivo and in vitro. Here we propose that there may be a key suppressive mechanism that is shared by every forkhead box p3 (Foxp3)+ Treg in vivo and in vitro in mice and humans. When this central mechanism is abrogated, it causes a breach in self-tolerance and immune homeostasis. Other suppressive mechanisms may synergistically operate with this common mechanism depending on the environment and the type of an immune response. Further, Treg-mediated suppression is a multi-step process and impairment or augmentation of each step can alter the ultimate effectiveness of Treg-mediated suppression. These findings will help to design effective ways for controlling immune responses by targeting Treg suppressive functions.
Summary Awake bruxism is defined as the awareness of jaw clenching. Its prevalence is reported to be 20% among the adult population. Awake bruxism is mainly associated with nervous tic and reactions ...to stress. The physiology and pathology of awake bruxism is unknown, although stress and anxiety are considered to be risk factors. During sleep, awareness of tooth grinding (as noted by sleep partner or family members) is reported by 8% of the population. Sleep bruxism is a behaviour that was recently classified as a ‘sleep‐related movement disorder’. There is limited evidence to support the role of occlusal factors in the aetiology of sleep bruxism. Recent publications suggest that sleep bruxism is secondary to sleep‐related micro‐arousals (defined by a rise in autonomic cardiac and respiratory activity that tends to be repeated 8–14 times per hour of sleep). The putative roles of hereditary (genetic) factors and of upper airway resistance in the genesis of rhythmic masticatory muscle activity and of sleep bruxism are under investigation. Moreover, rhythmic masticatory muscle activity in sleep bruxism peaks in the minutes before rapid eye movement sleep, which suggests that some mechanism related to sleep stage transitions exerts an influence on the motor neurons that facilitate the onset of sleep bruxism. Finally, it remains to be clarified when bruxism, as a behaviour found in an otherwise healthy population, becomes a disorder, i.e. associated with consequences (e.g. tooth damage, pain and social/marital conflict) requires intervention by a clinician.
The two-way transition between closed and open cellular convection is addressed in an idealized cloud-resolving modeling framework. A series of cloud-resolving simulations shows that the transition ...between closed and open cellular states is asymmetrical and characterized by a rapid ("runaway") transition from the closed- to the open-cell state but slower recovery to the closed-cell state. Given that precipitation initiates the closed-open cell transition and that the recovery requires a suppression of the precipitation, we apply an ad hoc time-varying drop concentration to initiate and suppress precipitation. We show that the asymmetry in the two-way transition occurs even for very rapid drop concentration replenishment. The primary barrier to recovery is the loss in turbulence kinetic energy (TKE) associated with the loss in cloud water (and associated radiative cooling) and the vertical stratification of the boundary layer during the open-cell period. In transitioning from the open to the closed state, the system faces the task of replenishing cloud water fast enough to counter precipitation losses, such that it can generate radiative cooling and TKE. It is hampered by a stable layer below cloud base that has to be overcome before water vapor can be transported more efficiently into the cloud layer. Recovery to the closed-cell state is slower when radiative cooling is inefficient such as in the presence of free tropospheric clouds or after sunrise, when it is hampered by the absorption of shortwave radiation. Tests suggest that recovery to the closed-cell state is faster when the drizzle is smaller in amount and of shorter duration, i.e., when the precipitation causes less boundary layer stratification. Cloud-resolving model results on recovery rates are supported by simulations with a simple predator-prey dynamical system analogue. It is suggested that the observed closing of open cells by ship effluent likely occurs when aerosol intrusions are large, when contact comes prior to the heaviest drizzle in the early morning hours, and when the free troposphere is cloud free.
Display omitted
•X-ray scattering data of copper/ethylene glycol nanofluid were analyzed by a generalized Langevin equation.•The μ- and α-structural relaxations of the solvent in the nanofluid are ...faster than those of pure ethylene glycol.•High-frequency sound velocity is related to the enhancement of thermal conductivity.
Inelastic X-ray scattering was measured for copper/ethylene glycol nanofluid at 298 K. The collective excitation of the solvent was analyzed by a generalized Langevin equation. The thermal diffusion coefficient and μ(fast)- and α(structure)-relaxations of the solvent for the nanofluid are larger and faster than those of pure liquid, respectively. The high-frequency sound velocity obtained from momentum transfer dependence of a maximum in the longitudinal current-current correlation function increases with increasing the number of copper nanoparticles. The enhanced thermal conductivity of copper/ethylene glycol nanofluid could be related to the solvent dynamics.
We present a numerical analysis of the rheology of a dense suspension of spherical capsules in simple shear flow in the Stokes flow regime. The behaviour of neo-Hookean capsules is simulated for a ...volume fraction up to
${\it\phi}=0.4$
by graphics processing unit computing based on the boundary element method with a multipole expansion. To describe the specific viscosity using a polynomial equation of the volume fraction, the coefficients of the equation are calculated by least-squares fitting. The results suggest that the effect of higher-order terms is much smaller for capsule suspensions than rigid sphere suspensions; for example,
$O({\it\phi}^{3})$
terms account for only 8 % of the specific viscosity even at
${\it\phi}=0.4$
for capillary numbers
$Ca\geqslant 0.1$
. We also investigate the relationship between the deformation and orientation of the capsules and the suspension rheology. When the volume fraction increases, the deformation of the capsules increases while the orientation angle of the capsules with respect to the flow direction decreases. Therefore, both the specific viscosity and the normal stress difference increase with volume fraction due to the increased deformation, whereas the decreased orientation angle suppresses the specific viscosity, but amplifies the normal stress difference.
PDF
