clock period
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2021 ◽  
Author(s):  
Eyal Bdolach ◽  
Manas Ranjan Prusty ◽  
Lalit Dev Tiwari ◽  
Khalil Kashkush ◽  
Eyal Fridman

In plants, the role of chloroplasts and mitochondria (plasmotype) in controlling circadian clock plasticity and overall plant robustness has not been elucidated. In this study, we investigated the rhythmicity of chlorophyll fluorescence (Chl F) clock output , and fitness in the field at optimal and elevated temperatures, in three different barley populations. First, we examined a reciprocal DH population between two wild barley (Hordeum vulgare ssp. spontaneum), in which we identified two pleiotropic QTLs (frp2.1 and amp7.1) that modulate clock and fitness including conditioning of these effects by plasmotype diversity. In the second population, a complete diallel consisting of 11 genotypes (reciprocal hybrids differing in plasmotype), we observed a gradual reduction in plasmotype, ranging from 26% and 15% for Chl F and clock measurements to 5.3% and 3.7% for growth and reproductive traits, respectively. The third population studied was a collection of cytolines in which nine different wild plasmotypes replaced the cultivated Noga (H. vulgare) plasmotype. Here, the order and magnitude of the effects of the plasmotypes differed from what we observed in the diallel population, with the greatest effect of plasmotype diversity observed for clock period and amplitude. Comparison of the chloroplast sequences suggests several candidate genes in the plastid-encoded RNA polymerase (PEP) complex that may be responsible for the observed plasmotype effects. Overall, our results unravel previously unknown cytonuclear epistatic interactions that controls clock performance while also having pleiotropic effects on a plant field characteristics.


Author(s):  
Jennifer L. Creaser ◽  
Casey O. Diekman ◽  
Kyle C. A. Wedgwood

Circadian rhythms are established by the entrainment of our intrinsic body clock to periodic forcing signals provided by the external environment, primarily variation in light intensity across the day/night cycle. Loss of entrainment can cause a multitude of physiological difficulties associated with misalignment of circadian rhythms, including insomnia, excessive daytime sleepiness, gastrointestinal disturbances, and general malaise. This can occur after travel to different time zones, known as jet lag; when changing shift work patterns; or if the period of an individual’s body clock is too far from the 24 h period of environmental cycles. We consider the loss of entrainment and the dynamics of re-entrainment in a two-dimensional variant of the Forger-Jewett-Kronauer model of the human circadian pacemaker forced by a 24 h light/dark cycle. We explore the loss of entrainment by continuing bifurcations of one-to-one entrained orbits under variation of forcing parameters and the intrinsic clock period. We show that the severity of the loss of entrainment is dependent on the type of bifurcation inducing the change of stability of the entrained orbit, which is in turn dependent on the environmental light intensity. We further show that for certain perturbations, the model predicts counter-intuitive rapid re-entrainment if the light intensity is sufficiently high. We explain this phenomenon via computation of invariant manifolds of fixed points of a 24 h stroboscopic map and show how the manifolds organise re-entrainment times following transitions between day and night shift work.


2021 ◽  
Author(s):  
Shin-ichi Koda ◽  
Shinji Saito

Circadian clocks tick a rhythm with a nearly 24-hour period in various organisms. The clock proteins of cyanobacteria, KaiA, KaiB, and KaiC, compose a minimum circadian clock. The slow KaiB-KaiC complex formation, which is essential in determining the clock period, occurs when the C1 domain of KaiC binds ADP produced by ATP hydrolysis. KaiC is considered to promote this complex formation by inhibiting the backward process, ADP/ATP exchange, rather than activating the forward process, ATP hydrolysis. Remarkably, although inhibition of backward process, in general, decelerates the whole process, KaiC oppositely accelerates the complex formation. In this article, by building a novel reaction model, we investigate the molecular mechanism of the simultaneous promotion and acceleration of the complex formation, which may play a significant role in keeping the period invariant under environmental perturbations. Based on several experimental results, we assume in this model that six KaiB monomers cooperatively and rapidly binds to C1 with the stabilization of the binding-competent conformation of C1 only when C1 binds six ADP. We find the cooperative KaiB binding effectively separates the pre-binding process of C1 into a fast transformation to binding-competent C1 requiring multiple ATP hydrolyses and its slow backward transformation. Since the ADP/ATP exchange retards the forward process, its inhibition results in the acceleration of the complex formation. We also find that, in a simplified monomeric model where KaiB binds to a KaiC monomer independently of the other monomers, the ADP/ATP exchange inhibition cannot accelerate the complex formation. In summary, we conclude that the ring-shaped hexameric form of KaiC enables the acceleration of the complex formation induced by the backward process inhibition because the cooperative KaiB binding arises from the structure of KaiC.


2021 ◽  
Vol 14 (2) ◽  
pp. 1-21
Author(s):  
Zhen Zhou ◽  
Debiao He ◽  
Zhe Liu ◽  
Min Luo ◽  
Kim-Kwang Raymond Choo

As quantum computers become more affordable and commonplace, existing security systems that are based on classical cryptographic primitives, such as RSA and Elliptic Curve Cryptography ( ECC ), will no longer be secure. Hence, there has been interest in designing post-quantum cryptographic ( PQC ) schemes, such as those based on lattice-based cryptography ( LBC ). The potential of LBC schemes is evidenced by the number of such schemes passing the selection of NIST PQC Standardization Process Round-3. One such scheme is the Crystals-Dilithium signature scheme, which is based on the hard module-lattice problem. However, there is no efficient implementation of the Crystals-Dilithium signature scheme. Hence, in this article, we present a compact hardware architecture containing elaborate modular multiplication units using the Karatsuba algorithm along with smart generators of address sequence and twiddle factors for NTT, which can complete polynomial addition/multiplication with the parameter setting of Dilithium in a short clock period. Also, we propose a fast software/hardware co-design implementation on Field Programmable Gate Array ( FPGA ) for the Dilithium scheme with a tradeoff between speed and resource utilization. Our co-design implementation outperforms a pure C implementation on a Nios-II processor of the platform Altera DE2-115, in the sense that our implementation is 11.2 and 7.4 times faster for signature and verification, respectively. In addition, we also achieve approximately 51% and 31% speed improvement for signature and verification, in comparison to the pure C implementation on processor ARM Cortex-A9 of ZYNQ-7020 platform.


2021 ◽  
pp. 074873042110129
Author(s):  
Mitsugu Sujino ◽  
Satoshi Koinuma ◽  
Yoichi Minami ◽  
Yasufumi Shigeyoshi

Heavy water lengthens the periods of circadian rhythms in various plant and animal species. Many studies have reported that drinking heavy water lengthens the periods of circadian activity rhythms of rodents by slowing the clock mechanism in the suprachiasmatic nucleus (SCN), the mammalian circadian center. The SCN clock is stable and robust against disturbance, due to its intercellular network. It is unclear whether this robustness provides resistance to the effects of heavy water. Here, we report that heavy water lengthened the rhythm period of clock gene expression of the SCN and peripheral tissues in vitro using a PERIOD2::LUCIFERASE bioluminescence reporter. Our results show that the period-elongation rate of the SCN is similar to those of other tissues. Therefore, the intercellular network of the SCN is not resistant to the period-elongation effect of heavy water.


Author(s):  
V. G. Mikhailov

Use of CAN BUS for data transmission in Real-Time mode with Simulink on control objects is considered (6-DoF a platform).It is revealed that software of CAN_ API.dll adapters, created in the Microsoft Visual Studio (MVS) does not work with TDM-GCC-64 Matlab/Simulink because of different approach in names of the dll functions according to the standard C ++ 11/17. Recompile by the developer of the adapter of its software (dll) in the TDM-GCC-64 environment under Windows is required.It is established that CAN BUS considerably reduces modeling speed by 4.5 times. The way of information compression and fall forward of exchange twice due to byte-by-byte entering of two float values in the data field is offered. Use of identical values of identifiers is applied to two cylinders 6-DoF of a platform and the subsequent their division in the program microcontrollers of cylinders.For implementation of a Real-Time mode in addition to compression it is offered to transfer data with the smaller frequency (quantization) by what a modeling clock period. It was considered that 6-DoF platforms reproduce frequency band to 10–12 Hz. The program of transfer/data exchange with Simulink on stand control devices with quantization is developed. Influence of parameter of quantization for the period of modeling is investigated. It is established that the Real-Time mode of modeling is provided in the range of parameters of quantization (chc=1/350–1/1000). Frequency of exchange with 6 cylinders at the same time corresponds to 230, 150 Hz.


2021 ◽  
Vol 12 ◽  
Author(s):  
Juhyeon Lee ◽  
Myeong Hoon Kang ◽  
Jung Yeon Kim ◽  
Pyung Ok Lim

Leaf senescence is an integrated response of the cells to develop age information and various environmental signals. Thus, some of the genes involved in the response to environmental changes are expected to regulate leaf senescence. Light acts not only as the primary source of energy for photosynthesis but also as an essential environmental cue that directly control plant growth and development including leaf senescence. The molecular mechanisms linking light signaling to leaf senescence have recently emerged, exploring the role of Phytochrome-Interacting Factors (PIFs) as a central player leading to diverse senescence responses, senescence-promoting gene regulatory networks (GRNs) involving PIFs, and structural features of transcription modules in GRNs. The circadian clock is an endogenous time-keeping system for the adaptation of organisms to changing environmental signals and coordinates developmental events throughout the life of the plant. Circadian rhythms can be reset by environmental signals, such as light-dark or temperature cycles, to match the environmental cycle. Research advances have led to the discovery of the role of core clock components as senescence regulators and their underlying signaling pathways, as well as the age-dependent shortening of the circadian clock period. These discoveries highlight the close relationship between the circadian system and leaf senescence. Key issues remain to be elucidated, including the effect of light on leaf senescence in relation to the circadian clock, and the identification of key molecules linking aging, light, and the circadian clock, and integration mechanisms of various senescence-affecting signals at the multi-regulation levels in dynamics point of view.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Uma ◽  
P. Kalpana

AbstractThis paper presents an area-efficient folded wavelet filter-based Electrocardiogram (ECG) detector for cardiac pacemakers. The modified folded undecimator based detector consists of Wavelet Filter Bank, QRS complex detector with Generalized Likelihood Ratio Test (GLRT) block and noise detector. A high-level transformation technique such as folding transformation and Cutset retiming are applied to the GLRT block in order to reduce the silicon area. Folding is a high-level transformation applied at the architectural level to enhance the performance of DSP architectures. It reduces the number of adders, multipliers and delay elements in the architecture. The Cutset retiming reduces clock period of the architecture by changing position of delay elements in the critical path. The folding transformation and cutset retiming implement the functional blocks of the GLRT circuit with minimum hardware. The modified folded ECG detector is tested for short term and long-term MIT-BIH databases. The results show that the modified folded undecimator detector has hardware savings and achieves sensitivity of 99.95%, positive prediction of 99.97% and Detection Error Rate (DER) of 0.061. The folded GLRT block architecture is synthesized with FPGA Zed board XC7Z010CLG484-1. Results show that the device utilization and power consumption are lesser than the conventional GLRT structure.


Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1665
Author(s):  
Paolo Visconti ◽  
Stefano Capoccia ◽  
Eugenio Venere ◽  
Ramiro Velázquez ◽  
Roberto de Fazio

The security of communication and computer systems is an increasingly important issue, nowadays pervading all areas of human activity (e.g., credit cards, website encryption, medical data, etc.). Furthermore, the development of high-speed and light-weight implementations of the encryption algorithms is fundamental to improve and widespread their application in low-cost, low-power and portable systems. In this scientific article, a high-speed implementation of the AES-128 algorithm is reported, developed for a short-range and high-frequency communication system, called Wireless Connector; a Xilinx ZCU102 Field Programmable Gate Array (FPGA) platform represents the core of this communication system since manages all the base-band operations, including the encryption/decryption of the data packets. Specifically, a pipelined implementation of the Advanced Encryption Standard (AES) algorithm has been developed, allowing simultaneous processing of distinct rounds on multiple successive plaintext packets for each clock period and thus obtaining higher data throughput. The proposed encryption system supports 220 MHz maximum operating frequency, ensuring encryption and decryption times both equal to only 10 clock periods. Thanks to the pipelined approach and optimized solutions for the Substitute Bytes operation, the proposed implementation can process and provide the encrypted packets each clock period, thus obtaining a maximum data throughput higher than 28 Gbit/s. Also, the simulation results demonstrate that the proposed architecture is very efficient in using hardware resources, requiring only 1631 Configurable Logic Blocks (CLBs) for the encryption block and 3464 CLBs for the decryption one.


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