Neuronal sequences during theta rely on behavior-dependent spatial maps

Navigation through space involves learning and representing relationships between past, current and future locations. In mammals, this might rely on the hippocampal theta phase code, where in each cycle of the theta oscillation, spatial representations provided by neuronal sequences start behind the animal's true location and then sweep forward. However, the exact relationship between theta phase, represented position and true location remains unclear and even paradoxical. Here, we formalize previous notions of 'spatial' or 'temporal' theta sweeps that have appeared in the literature. We analyze single-cell and population variables in unit recordings from rat CA1 place cells and compare them to model simulations based on each of these schemes. We show that neither spatial nor temporal sweeps quantitatively accounts for how all relevant variables change with running speed. To reconcile these schemes with our observations, we introduce 'behavior-dependent' sweeps, in which theta sweep length and place field properties, such as size and phase precession, vary across the environment depending on the running speed characteristic of each location. These behavior-dependent spatial maps provide a structured heterogeneity that is essential for understanding the hippocampal code.

EXPERIMENTAL RESEARCH OF RE-EQUIPMENT A WHEELED VEHICLE INTO A ELECTROMOBILE

The article presents the results of the carried out road tests of a wheeled vehicle of category M1, which was re-equipment into a electromobile. The electromobile is equipped with a traction electric motor Balkankar DS 3.6/7.5/14, a power storage battery on lithium cells with a maximum voltage of 100.8 V and a capacity of 6.45 kW∙h. The traction motor control system is impulse with electronic power switches. As a result of the road tests carried out, the maximum speed of movement, the acceleration time on a given path, the acceleration time to the given speed, the “acceleration – coasting” speed characteristic were determined and acceleration was carried out in gears that ensure the maximum speed. Comparison of the results of theoretical and experimental studies testifies to the adequacy of the developed mathematical model and the initial data that form the basis for calculating the indicators of re-equipped wheeled vehicle into electromobile.

Behavior-dependent spatial maps enable efficient theta phase coding

Navigation through space involves learning and representing relationships between past, current and future locations. In mammals, this might rely on the hippocampal theta phase code, where in each cycle of the theta oscillation, spatial representations start behind the animal’s location and then sweep forward. However, the exact relationship between phase and represented and true positions remains unclear and even paradoxical. Here, we formalize previous notions as ‘spatial’ or ‘temporal’ sweeps, analyze single-cell and population variables in recordings from rat CA1 place cells, and compare them to model simulations. We show that neither sweep type quantitatively accounts for all relevant variables. Thus we introduce ‘behavior-dependent’ sweeps, which fit our key observation that sweep length, and hence place field properties, such as size and phase precession, vary across the environment depending on the running speed characteristic of each location. This structured heterogeneity is essential for understanding the hippocampal code.

The glycocalyx affects force loading-dependent mechanotransductive topography sensing at the nanoscale

ABSTRACTThe cell/microenvironment interface is the starting point of integrin-mediated mechanotransduction, but many details of mechanotransductive signal integration remain elusive due to the complexity of the involved (extra)cellular structures, such as the glycocalyx.We used engineered nano-bio interfaces with extracellular matrix nanotopography-mimicking features to analyse the impact of the glycocalyx on nano-mechanosensing. Our data demonstrates that the glycocalyx configuration affects spatiotemporal nanotopography-sensitive mechanotransductive events at the cell/microenvironment interface. Opposing effects of glycocalyx removal were observed, when comparing flat and specific nanotopographical conditions (i.e., 15 nm root-mean-square (rms) roughness). In fact, the excessive force loading and retrograde actin flow speed, characteristic for the 15 nm rms nanotopography in the presence of native glycocalyx, are strongly reduced in its absence. Conversely, on the flat substrate, these parameters increased upon glycocalyx-targeting enzymatic treatment.Our results highlight the importance of the glycocalyx configuration in a molecular clutch force loading-dependent cellular mechanism for nano-mechanosensing of the topography.

Synchronous Reluctance Machines for Automotive Cooling Fan Systems: Numerical and Experimental Study of Different Slot-Pole Combinations and Winding Types

In this paper a side-by-side comparison between synchronous reluctance machines (SynRMs) with concentrated and distributed windings is performed. The characteristics, parameters, and the installation space of a permanent magnet synchronous machine (PMSM) with concentrated windings used in a 13 V automotive cooling fan system (CFMs) are used as requirements and specifications. For that, eight SynRMs with different stator and rotor topologies are investigated and optimized by means of FE-based electromagnetic optimization. Knowing the challenges associated with the development of mechanically stable SynRM rotor structures, for two selected cross-sections in view of being prototyped, designs checks are performed to ensure robust operation at up to two times the required operating speed. The simulated results were verified by means of measurements performed using two different types of loading systems, i.e., with the real ventilator and using a DC machine as a load. Based on this, the relative differences between all three motor technologies in terms of important quantities (e.g., torque-speed characteristic, torque ripple, efficiency, power factor and ultimately the size) are highlighted.

Modelling of diesel generator operating modes on the basis of the engine speed characteristic in autonomous photovoltaic systems

The article presents a universal diesel generator model based on the processing of the engine speed characteristic. Processing uses linear interpolation with a fixed discrete step. An autonomous photovoltaic system arbitrarily located in Eastern Siberia is used as a case study. Solar radiation modelling was based on multi-year meteorological data sets using the tandem of Iqbal-Kasten/Czeplak models. The photovoltaic system under investigation consists of two 400 kW diesel generators (totalling 800 kW) and one 375 kW solar power plant. In calculating the operating modes, the diesel power plant’s minimum limit load factor was taken into consideration. The resulting values of the diesel generator’s operating modes show the following patterns. As an example, the lesser the diesel generator’s load, the lesser engine speed and the higher specific fuel consumption. The suggested model can be used in comprehensive energy research, specifically in areas such as optimal equipment configuration, operational reliability and sustainability as well as cost-efficiency.

Two Phase Motor Fed from Controlled Supply

<p>Compared to single phase operation, a good utilization of machine material is achieved by supplying the two-phase stator windings from a controlled supply. It is necessary to start from the known equivalent circuits of both forward and backward components to obtain the relations between the sequence and the phase voltage values. In this method of control, the torque expression is driven in a simple form and the torque speed characteristic are computed and plotted for different values of the time-phase angle. The operation of 2-phase motor from single phase supply carried out by connecting one stator phase directly to the voltages source, with exciting the second stator phase through the phase shifting element. In this method, the starting and the maximum torque values can be controlled by changing the stator field from a pulsating of (0 o ) to a pure rotating field at (90 o ).</p>

Optimization of the ethanol-fuel emulsion composition for use in diesel engines

The use of alternative fuels of biological origin, in particular, alcohols, should be considered as a matter for the very near future. Scientists around the world are exploring more and more concen-trated compositions of ethanol-fuel emulsions with various additives. However, to date, the reason-able limits of substitution of diesel fuel with ethanol have not been determined. Taking into account the depth of the problem, first of all, it is necessary to consider the creation of ethanol-fuel emul-sions with a number of necessary properties, which is possible only if additives are used. The analy-sis of the additives used in the fuel showed that the directional effect of the additives is usually very narrow. Accordingly, a complex action additive is required to ensure a number of necessary properties of ethanol-fuel emulsions. The tests were carried out in several stages. The stability of the new fuel composition was investigated using various additives. The additive with the best performance was determined and adopted for further use in experiments. Further, the comparative tests of the operation of the fuel supply equipment, both on the basic fuel and on new fuel compositions, were carried out. The final stage of the research was to check the parameters of the engine operability as a whole when working at the main load and speed modes. The article considers a possible variant of the action of a complex additive based on molybdenum disulfide MoS2 as a combustion ignibitor. A hypothetical type and mechanism of reactions occurring in the combustion chamber of a diesel engine is presented. The results of experiments on the performance of injectors 455.1112010-50 on various compositions of new fuels and under changing conditions are shown. Environmental performance indicators of the 4ChN 11.0 / 12.5 engine are considered when operating according to the external speed characteristic on various fuel compositions. Based on the results of the data analysis, conclusions were drawn about the limitation of the presence of ethanol in the mixture and the substitution limit for the main fuel was justified.