Search

Social hierarchies emerged during evolution, and social rank influences behavior and health of individuals. However, the evolutionary mechanisms of social hierarchy are still unknown in amniotes. Here we developed a new method and performed a genome-wide screening for identifying regions with accelerated evolution in the ancestral lineage of placental mammals, where mammalian social hierarchies might have initially evolved. Then functional analyses were conducted for the most accelerated region designated as placental-accelerated sequence 1 (PAS1, P = 3.15 × 10-18). Multiple pieces of evidence show that PAS1 is an enhancer of the transcription factor gene Lhx2 involved in brain development. PAS1s isolated from various amniotes showed different cis-regulatory activity in vitro, and affected the expression of Lhx2 differently in the nervous system of mouse embryos. PAS1 knock-out mice lack social stratification. PAS1 knock-in mouse models demonstrate that PAS1s determine the social dominance and subordinate of adult mice, and that social ranks could even be turned over by mutated PAS1. All homozygous mutant mice had normal huddled sleeping behavior, motor coordination and strength. Therefore, PAS1-Lhx2 modulates social hierarchies and is essential for establishing social stratification in amniotes, and positive Darwinian selection on PAS1 plays pivotal roles in the occurrence of mammalian social hierarchies.

Significant progress has been made in the research of all-optical neural networks in recent years. In this paper, we theoretically explore the properties of a neural system composed of semiconductor ring lasers (SRLs). Our study demonstrates that external optical signals generated by a tunable laser (TL) are injected into the first semiconductor ring laser photonic neuron (SRL1). Subsequently, the responses of SRL1 in the clockwise (CW) and counterclockwise (CCW) directions are unidirectionally injected into the CW and CCW directions of the second semiconductor ring laser photonic neuron (SRL2), respectively, which then exhibits similar spiking inhibition behaviors. Numerical simulations reveal that the spiking inhibition behavior of the SRL response can be precisely controlled by adjusting the perturbation time and intensity of the external injection signal, and this behavior is highly repeatable. Most importantly, we successfully achieve the stable transmission of these responses between the two SRL photonic neurons. These inhibition behaviors are analogous to those of biological neurons, but with a response speed reaching the sub-nanosecond level. Additionally, we indicate that SRL photonic neurons undergo a refractory-period-like phenomenon when subjected to two consecutive perturbations. These findings highlight the immense potential for the design and implementation of future all-optical neural networks, providing critical theoretical foundations and support for them. [ABSTRACT FROM AUTHOR]

In this paper, we propose using a chaotic system composed of nanolasers (NLs) as a physical entropy source. Combined with post-processing technologies, this system can produce high-quality physical random number sequences. We investigated the parameter range for achieving time-delay signature (TDS) concealment in the chaotic system. This study demonstrates that NLs exhibit noticeable TDS only under optical feedback. As mutual injection strength between the master NLs (MNLs) increases, the TDS of the MNLs is gradually suppressed until they are completely concealed. Compared to MNLs, the slave NL (SNL) exhibits better TDS suppression performance. Additionally, we investigated the chaotic and highly unpredictable regions of the SNL, demonstrating that high-quality chaotic signals can be produced over a wide range of parameters. Using TDS hidden and highly unpredictable chaotic signals as the source of random entropy, the effects of different post-processing techniques on random number extraction were compared. The results indicate that effective post-processing can enhance the unpredictability of the random sequence. This study successfully utilized NLs for random number generation, showcasing the potential and application prospects of NLs in the field of random numbers. [ABSTRACT FROM AUTHOR]

Vehicle active safety systems can improve vehicle security by avoiding collisions. An autonomous emergency braking (AEB) system's safety distance calculation is usually based on normal weather conditions. The AEB system's early warning capabilities decrease during adverse weather conditions. A multilayer perceptron (MLP) model is used to obtain data from accident and weather data sets. The MLP model is trained and the severity of accidents is predicted. The severity is used as a parameter to build an adaptive AEB system algorithm that considers adverse weather conditions. The adaptive AEB system algorithm increases safety and reliability under adverse weather conditions. Prescan and a driver-in-the-loop system are used to test the adaptive AEB model. Both tests show that the adaptive AEB model has better performance under adverse weather than the traditional AEB model. The experimental results demonstrate that the adaptive AEB system can increase the safety distance in rainy weather and avoid collisions under hazy conditions. [ABSTRACT FROM AUTHOR]

The contra‐rotating machine (CRM) has been a preferable selection of the contra‐rotating propulsion system (CRPS) owing to its high efficiency, high compactness, and low noise. However, the conventional CRM with rotating stator has the problem of brush and slip ring, and the conventional brushless CRM has the problem of coordinated control of equal and opposite torque. Aiming at the above problems, this article proposes a transverse‐dislocated magnetic‐field modulated brushless contra‐rotating machine (TDMFM‐BCRM). The proposed TDMFM‐BCRM has some advantages of no rotating winding, no associated brushes and slip rings, and equal and opposite torques at any time, therefore it has good potential for the CRPS. The working principle of the TDMFM‐BCRM including three dimensional magnetic‐field modulated theory, back electromotive force (EMF) generation, and torque relation is studied. Then, the influences of main parameters including magnetic block parameters and PM sizes on torques are investigated. The critical electromagnetic performances of the TDMFM‐BCRM are analysed. A prototype of TDMFM‐BCRM is manufactured and measured to validate the above analysis. Finally, the comparison of the TDMFM‐BCRM and the existing schemes are analysed. [ABSTRACT FROM AUTHOR]

Requirements about controller of electrical control system were analyzed according to condition of roadheader working field. For low protection hierarchy and poor environment adaptability of traditional electrical control system of roadheader which took PLC as a core, an appropriative controller named Inter Control was taken as a core of electrical control system of roadheader on the basis of performance comparisons of existing appropriative controllers. Hardware composition of the electrical control was introduced in detail as well as design scheme of controller program. Inter Control controller has been successfully applied to an electrical control system of all-rock roadheader. The industrial test underground shows the electrical control system overcomes disadvantages of traditional ones based on PLC, and runs stably and reliably without any communication faults.

As a promising candidate of the electrical continuously variable transmission, the integrated magnetic-field-modulated brushless compound-structure machine (IMFM-BCSM) has advantages of compact structure and no brush. The IMFM-BCSM is composed of a stator with two sets of windings, a permanent-magnet (PM) rotor and a modulation rotor. Due to its special operating principle, i.e., the magnetic field modulation principle, the back electromotive force (EMF) waveform distortion of the IMFM-BCSM is more serious than that of the conventional PM machine. To solve the above problem, a quasi-sinusoidal concentrated winding (QSCW) configuration is proposed and corresponding design method is further introduced. In order to observe the “filtering ability” of the QSCW, comparisons between QSCW configuration and fractional-slot concentrated winding configuration are carried out. The results show that when the QSCW configuration is employed, the no-load back EMF of the regular winding is more sinusoidal; the distortion degree is less affected by the rotor speeds; and the torque ripple is much smaller. Finally, a prototype is manufactured to verify the theoretical analysis. [ABSTRACT FROM AUTHOR]