In the brain of holometabolous insects such as the fruit fly Drosophila melanogaster, the fruitless gene produces sex‐specific gene products under the control of the sex‐specific splicing cascade and ...contributes to the formation of the sexually dimorphic circuits. Similar sex‐specific gene products of fruitless homologues have been identified in other holometabolous insects such as mosquitoes and a parasitic wasp, suggesting the fruitless‐dependent neural sex‐determination system is widely conserved amongst holometabolous insects. However, it remains obscure whether the fruitless‐dependent neural sex‐determination system is present in basal hemimetabolous insects. To address this issue, identification, characterization, and expression analyses of the fruitless homologue were conducted in the two‐spotted cricket, Gryllus bimaculatus, as a model hemimetabolous insect. The Gryllus fruitless gene encodes multiple isoforms with a unique zinc finger domain, and does not encode a sex‐specific gene product. The Gryllus Fruitless protein is broadly expressed in the neurones and glial cells in the brain, and there was no prominent sex‐related difference in the expression levels of Gryllus fruitless isoforms. The results suggest that the Gryllus fruitless gene is not involved in the neural sex‐determination in the cricket brain.
A unified model for the feedback and ballooning instabilities in the magnetosphere‐ionosphere (M‐I) coupling is developed by means of the reduced magnetohydrodynamic and two‐fluid equations, ...involving the local current closure and the ionospheric conductivity change in a scale of auroral fine structures, self‐consistently. In a low pressure gradient case, the Alfvén harmonics are destabilized through the feedback mechanism, while the ballooning instability appears if the magnetospheric pressure gradient exceeds a critical value. Transition of the dominant instability between the feedback and ballooning modes is brought by change of the normalized pressure gradient or the convection electric field in the magnetosphere. The obtained results imply a variety of appearance of auroral arcs and beads in the M‐I coupling system.
Plain Language Summary
A novel explanation on generation of arc and beading structures of auroras is provided by means of theoretical analysis based on the first principle of plasma physics. The theory predicts competition of two different types of perturbation growth, leading to a variety of auroral appearance.
Key Points
A new magnetosphere‐ionosphere coupling model is derived, where the feedback and ballooning instabilities are simultaneously described
Transition of dominant instability mode is brought by change of pressure gradient or convection electric field in the magnetosphere
The magnetosphere‐ionosphere coupling theory predicts a novel scenario on the auroral beading and preexisting arcs
•A contour dynamics method is applied to the Vlasov-Poisson system.•An efficient implementation of the periodic boundary condition is proposed.•The new method is benchmarked for the linear and ...nonlinear Landau damping.•Energy and particle conservation is examined for the benchmark test.•Particle trapping process is well captured by the contour dynamics method.
We revisit the contour dynamics (CD) simulation method which is applicable to large deformation of distribution function in the Vlasov-Poisson plasma with the periodic boundary, where contours of distribution function are traced without using spatial grids. Novelty of this study lies in application of CD to the one-dimensional Vlasov-Poisson plasma with the periodic boundary condition. A major difficulty in application of the periodic boundary is how to deal with contours when they cross the boundaries. It has been overcome by virtue of a periodic Green's function, which effectively introduces the periodic boundary condition without cutting nor reallocating the contours. The simulation results are confirmed by comparing with an analytical solution for the piece-wise constant distribution function in the linear regime and a linear analysis of the Landau damping. Also, particle trapping by Langmuir wave is successfully reproduced in the nonlinear regime.
Abstract We investigate the effect of the electron temperature gradient (ETG) driven turbulence on the energy transport in JT-60U L-mode plasma by means of the multi-scale gyrokinetic simulation. In ...the core region at r / a = 0.5 , the instability in the ion scale is driven by the ion temperature gradient (ITG), meanwhile strong unstable ETG modes are found in the electron scale. The nonlinear multi-scale gyrokinetic simulation shows that ETG modes are stabilized in the nonlinear phase and the energy transport in the multi-scale simulation is similar to that obtained in the ion scale ITG simulation. In an outer region at r / a = 0.6 , the ion scale instability changes to be the trapped electron mode (TEM). The multi-scale simulation shows that both the ion and the electron energy flux are reduced by ∼ 30 % compared to those obtained in the single scale TEM simulation. Interestingly, the electron energy flux is close to the experimental value after this reduction. From the data analyses, we find that ETG turbulence damps the energy of TEM modes through the ion scale/electron scale coupling and the electron scale/electron scale coupling, and can be modeled as a turbulent diffusion of TEM modes. These results suggest that the single ion scale simulation seems to be still valid in the inner region with r / a < 0.5 . However, in the outer region it is necessary to include the ETG modes in the gyrokinetic simulations to explain the energy transport in this L-mode plasma. This is the first result showing that ETG turbulence can reduce the electron energy loss via the cross-scale interaction in a real tokamak equilibrium profile.
Numerical simulations are performed to study the characteristics of thermo-acoustic oscillation of a gas confined in a loop-type pipe with the section of short and narrow channels. In order to ...simulate the irreversible heat exchange between the gas and the pipe wall, the compressible mass, momentum and energy conservation equations are solved in the loop pipe as well as the heat conduction equations in the pipe wall. Spontaneous oscillations are obtained when the temperature gradient along the narrow channel becomes large. It is found that the onset temperature of simulated thermo-acoustic oscillation agrees with that of the stability analysis and increases when the effect of gravity is not taken into account.
A linear eigenmode analysis of the magnetosphere‐ionosphere coupling shows that the feedback instability leading to spontaneous formation of auroral arc structures remains unstable even in a case ...with strong vertical shear of horizontal ion flows induced by ion‐neutral collisions in the E layer. For low‐order Alfvén harmonics, the linear frequency and growth rate obtained by means of a height‐resolved model of the ionosphere are comparable to those resulted from the height‐integrated one, where fine vertical structures of the ionospheric density and magnetic field perturbations are well resolved in the former. The present result confirms validity of the height‐integrated ionosphere model in the long parallel wavelength limit, as assumed in previous studies on the feedback instability.
Plain Language Summary
Spontaneous formation of auroral arcs can be explained in terms of a plasma instability in the magnetosphere‐ionosphere coupling. The present study confirms validity and robustness of the basic instability theory even in cases with inhomogeneous profiles of the ionospheric parameters such as the ion‐neutral collision.
Key Points
Feedback instability in the magnetosphere‐ionosphere coupling is unstable even in a case with strong vertical flow shear in the E layer
The linear eigenmode analysis captures entire profiles of the electromagnetic fields and the density perturbations along a field line
A conventional magnetosphere‐ionosphere coupling model with a height‐integrated ionosphere remains valid in a low‐frequency regime
Immunopathogenesis of pancreatitis Watanabe, T; Kudo, M; Strober, W
Mucosal immunology,
03/2017, Letnik:
10, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The conventional view of the pathogenesis of acute and chronic pancreatitis is that it is due to a genetic- or environment-based abnormality of intracellular acinar trypsinogen activation and thus to ...the induction of acinar cell injury that, in turn, sets in motion an intra-pancreatic inflammatory process. More recent studies, reviewed here, present strong evidence that while such trypsinogen activation is likely a necessary first step in the inflammatory cascade underlying pancreatitis, sustained pancreatic inflammation is dependent on damage-associated molecular patterns-mediated cytokine activation causing the translocation of commensal (gut) organisms into the circulation and their induction of innate immune responses in acinar cells. Quite unexpectedly, these recent studies reveal that the innate responses involve activation of responses by an innate factor, nucleotide-binding oligomerization domain 1 (NOD1), and that such NOD1 responses have a critical role in the activation/production of nuclear factor-kappa B and type I interferon. In addition, they reveal that chronic inflammation and its accompanying fibrosis are dependent on the generation of IL-33 by injured acinar cells and its downstream induction of T cells producing IL-13. These recent studies thus establish that pancreatitis is quite a unique form of inflammation and one susceptible to newer, more innovative therapy.
Abstract
Multi-scale gyrokinetic theory and simulations of a toroidal magnetized plasma have revealed the existence of cross-scale interactions of the trapped electron mode (TEM) and the electron ...temperature gradient (ETG) turbulence. Reduction of the TEM instability growth rate in the ETG turbulence is clearly identified, and is well represented in the form of effective diffusion. A theoretical model based on the stochastic forcing by the ETG turbulence well describes the turbulent diffusion coefficient observed in multi-scale turbulence simulations.
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