4,899 research outputs found
Monte Carlo Hamiltonian: Inverse Potential
The Monte Carlo Hamiltonian method developed recently allows to investigate
ground state and low-lying excited states of a quantum system, using Monte
Carlo algorithm with importance sampling. However, conventional MC algorithm
has some difficulties when applying to inverse potentials. We propose to use
effective potential and extrapolation method to solve the problem. We present
examples from the hydrogen system.Comment: To appear in Communications in Theoretical Physic
Soybean \u3ci\u3eGm\u3c/i\u3eSAUL1, a Bona Fide U-Box E3 Ligase, Negatively Regulates Immunity Likely through Repressing the Activation of \u3ci\u3eGm\u3c/i\u3eMPK3
E3 ubiquitin ligases play important roles in plant immunity, but their role in soybean has not been investigated previously. Here, we used Bean pod mottle virus (BPMV)-mediated virusinduced gene silencing (VIGS) to investigate the function of GmSAUL1 (Senescence-Associated E3 Ubiquitin Ligase 1) homologs in soybean. When two closely related SAUL1 homologs were silenced simultaneously, the soybean plants displayed autoimmune phenotypes, which were significantly alleviated by high temperature, suggesting that GmSAUL1a/1b might be guarded by an R protein. Interestingly, silencing GmSAUL1a/1b resulted in the decreased activation of GmMPK6, but increased activation of GmMPK3 in response to flg22, suggesting that the activation of GmMPK3 is most likely responsible for the activated immunity observed in the GmSAUL1a/1b-silenced plants. Furthermore, we provided evidence that GmSAUL1a is a bona fide E3 ligase. Collectively, our results indicated that GmSAUL1 plays a negative role in regulating cell death and immunity in soybean
The effect of experimental warming on leaf functional traits, leaf structure and leaf biochemistry in Arabidopsis thaliana
<p>Abstract</p> <p>Background</p> <p>The leaf is an important plant organ, and how it will respond to future global warming is a question that remains unanswered. The effects of experimental warming on leaf photosynthesis and respiration acclimation has been well studied so far, but relatively little information exists on the structural and biochemical responses to warming. However, such information is very important to better understand the plant responses to global warming. Therefore, we grew <it>Arabidopsis thaliana </it>at the three day/night temperatures of 23/18°C (ambient temperature), 25.5/20.5°C (elevated by 2.5°C) and 28/23°C (elevated by 5°C) to simulate the middle and the upper projected warming expected within the 21st century for this purpose.</p> <p>Results</p> <p>The 28/23°C treatment significantly reduced the life span, total biomass and total weight of seeds compared with the other two temperatures. Among the three temperature regimes, the concentrations of starch, chlorophyll, and proline were the lowest at 28/23°C, whereas the total weight of seeds, concentrations of chlorophyll and proline, stomatal density (SD), stomatal conductance (g<sub>s</sub>), net CO<sub>2 </sub>assimilation rate (A) and transpiration rate (E) were the highest at 25.5/20.5°C. Furthermore, the number of chloroplasts per cell and mitochondrial size were highest at 25.5/20.5°C and lowest at 28/23°C.</p> <p>Conclusions</p> <p>The conditions whereby the temperature was increased by 2.5°C were advantageous for <it>Arabidopsis</it>. However, a rise of 5°C produced negative effects, suggesting that lower levels of warming may benefit plants, especially those which belong to the same functional group as <it>Arabidopsis</it>, whereas higher levels of warming may produce negative affects. In addition, the increase in A under moderately warm conditions may be attributed to the increase in SD, chlorophyll content, and number of chloroplasts. Furthermore, starch accumulation in chloroplasts may be the main factor influencing chloroplast ultrastructure, and elevated temperature regulates plant respiration by probably affecting mitochondrial size. Finally, high SOD and CAT activities may enable plants grown at elevated temperatures to exhibit relatively high tolerance to temperature stress, thus alleviating the harmful effects of superoxide anion radicals and hydrogen peroxide.</p
A Ferroelectric Compute-in-Memory Annealer for Combinatorial Optimization Problems
Computationally hard combinatorial optimization problems (COPs) are
ubiquitous in many applications, including logistical planning, resource
allocation, chip design, drug explorations, and more. Due to their critical
significance and the inability of conventional hardware in efficiently handling
scaled COPs, there is a growing interest in developing computing hardware
tailored specifically for COPs, including digital annealers, dynamical Ising
machines, and quantum/photonic systems. However, significant hurdles still
remain, such as the memory access issue, the system scalability and restricted
applicability to certain types of COPs, and VLSI-incompatibility, respectively.
Here, a ferroelectric field effect transistor (FeFET) based compute-in-memory
(CiM) annealer is proposed. After converting COPs into quadratic unconstrained
binary optimization (QUBO) formulations, a hardware-algorithm co-design is
conducted, yielding an energy-efficient, versatile, and scalable hardware for
COPs. To accelerate the core vector-matrix-vector (VMV) multiplication of QUBO
formulations, a FeFET based CiM array is exploited, which can accelerate the
intended operation in-situ due to its unique three-terminal structure. In
particular, a lossless compression technique is proposed to prune typically
sparse QUBO matrix to reduce hardware cost. Furthermore, a multi-epoch
simulated annealing (MESA) algorithm is proposed to replace conventional
simulated annealing for its faster convergence and better solution quality. The
effectiveness of the proposed techniques is validated through the utilization
of developed chip prototypes for successfully solving graph coloring problem,
indicating great promise of FeFET CiM annealer in solving general COPs.Comment: 39 pages, 12 figure
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