4,873 research outputs found
Recombination frequencies of mutations located in wc-1 and wc-2.
Recombination frequencies of mutations located in wc-1 and wc-2
Onset and Evolution of the Oblique, Resonant Electron Firehose Instability in the Expanding Solar Wind Plasma
A double adiabatically expanding solar wind would quickly develop large parallel to perpendicular temperature anisotropies in electrons and ions that are not observed. One reason is that firehose instabilities would be triggered, leading to an ongoing driving/saturation evolution mechanism. We verify this assumption here for the first time for the electron distribution function and the electron firehose instability (EFI), using fully kinetic simulations with the Expanding Box Model. This allows the self-consistent study of onset and evolution of the oblique, resonant EFI in an expanding solar wind. We characterize how the competition between EFI and adiabatic expansion plays out in high- A nd low-beta cases, in high- A nd low-speed solar wind streams. We observe that, even when competing against expansion, the EFI results in perpendicular heating and parallel cooling. These two concurrent processes effectively limit the expansion-induced increase in temperature anisotropy and parallel electron beta. We show that the EFI goes through cycles of stabilization and destabilization: When higher wave number EFI modes saturate, lower wave number modes are destabilized by the effects of the expansion. We show how resonant wave/particle interaction modifies the electron velocity distribution function after the onset of the EFI. The simulations are performed with the fully kinetic, semi-implicit expanding box code EB-iPic3D
Combination of multicomponent KA2 and Pauson-Khand reactions: Short synthesis of spirocyclic pyrrolocyclopentenones
Gastrocnaemius-propeller extended miocutanous flap: a new chimaeric flap for soft tissue reconstruction of the knee
Specificity of Neuronal Responses in Primary Visual Cortex Is Modulated by Interhemispheric CorticoCortical Input
Within the visual cortex, it has been proposed that interhemispheric interactions serve to re-establish the continuity of the visual field across its vertical meridian (VM) by mechanisms similar to those used by intrinsic connections within a hemisphere. However, other specific functions of transcallosal projections have also been proposed, including contributing to disparity tuning and depth perception. Here, we consider whether interhemispheric connections modulate specific response properties, orientation and direction selectivity, of neurons in areas 17 and 18 of the ferret by combining reversible thermal deactivation in one hemisphere with optical imaging of intrinsic signals and single-cell electrophysiology in the other hemisphere. We found interhemispheric influences on both the strength and specificity of the responses to stimulus orientation and direction of motion, predominantly at the VM. However, neurons and domains preferring cardinal contours, in particular vertical contours, seem to receive stronger interhemispheric input than others. This finding is compatible with interhemispheric connections being involved in horizontal disparity tuning. In conclusion, our results support the view that interhemispheric interactions mainly perform integrative functions similar to those of connections intrinsic to one hemisphere
Lagrangian filtered density function for LES-based stochastic modelling of turbulent dispersed flows
The Eulerian-Lagrangian approach based on Large-Eddy Simulation (LES) is one
of the most promising and viable numerical tools to study turbulent dispersed
flows when the computational cost of Direct Numerical Simulation (DNS) becomes
too expensive. The applicability of this approach is however limited if the
effects of the Sub-Grid Scales (SGS) of the flow on particle dynamics are
neglected. In this paper, we propose to take these effects into account by
means of a Lagrangian stochastic SGS model for the equations of particle
motion. The model extends to particle-laden flows the velocity-filtered density
function method originally developed for reactive flows. The underlying
filtered density function is simulated through a Lagrangian Monte Carlo
procedure that solves for a set of Stochastic Differential Equations (SDEs)
along individual particle trajectories. The resulting model is tested for the
reference case of turbulent channel flow, using a hybrid algorithm in which the
fluid velocity field is provided by LES and then used to advance the SDEs in
time. The model consistency is assessed in the limit of particles with zero
inertia, when "duplicate fields" are available from both the Eulerian LES and
the Lagrangian tracking. Tests with inertial particles were performed to
examine the capability of the model to capture particle preferential
concentration and near-wall segregation. Upon comparison with DNS-based
statistics, our results show improved accuracy and considerably reduced errors
with respect to the case in which no SGS model is used in the equations of
particle motion
Phenylethynylbenzenesulfonamide regioisomers strongly and selectively inhibit the transmembrane tumor-associated carbonic anhydrase isoforms IX and XII over the cytosolic isoforms I and II
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Improving plastic management by means of people awareness
In past decades the usage of plastic has seen a tremendous increment. This raise is mainly caused by industrial development and by the spread of this material in every aspect of people life, from food package to aerospace application. For sure plastic has a key role in society and it is not possible to erase, nevertheless its overuse has a serious impact on the environment as well know. In particular, just a few percentage of the total amount of plastic is recycled, the rest has to be landfilled or burnt causing serious pollution side effect. This poor circularity in plastic value chain is mainly caused by difficulties in sorting processes and expensiveness of recycling. By the way a great part of plastic applications could be avoided without implying a reduction in life quality for the people. In addition, a better education in plastic objects shopping and plastic waste management could decrease the difficulties in sorting and recycling. One of the crucial reason why these applications and incorrect behaviour are still present is that the information on alternatives are not present or very hard to be found. In the present paper a novel platform to enhance a more plastic-free life is presented. First a detailed description of the problem is stated, then the process to achieve the proposed solution is described. Finally the platform prototype is analysed in details among its functionalities
Generation of Subion Scale Magnetic Holes from Electron Shear Flow Instabilities in Plasma Turbulence
Magnetic holes (MHs) are coherent structures associated with strong magnetic field depressions in magnetized plasmas. They are observed in many astrophysical environments at a wide range of scales, but their origin is still under debate. In this work, we investigate the formation of subion scale MHs using a fully kinetic 2D simulation of plasma turbulence initialized with parameters typical of the Earth’s magnetosheath. Our analysis shows that the turbulence is capable of generating subion scale MHs from large scale fluctuations via the following mechanism: first, the nonlinear large scale dynamics spontaneously leads to the development of thin and elongated electron velocity shears; these structures then become unstable to the electron Kelvin-Helmholtz instability and break up into small scale electron vortices; the electric current carried by these vortices locally reduces the magnetic field, inducing the formation of subion scale MHs. The MHs thus produced exhibit features consistent with satellite observations and with previous numerical studies. We finally discuss the kinetic properties of the observed subion scale MHs, showing that they are characterized by complex non-Maxwellian electron velocity distributions exhibiting anisotropic and agyrotropic features
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