Residual entropy from temperature incremental Monte Carlo method

Residual entropy, indicative of the degrees of freedom in a system at absolute zero, is a cornerstone for understanding quantum and classical ground states. Despite its critical role in elucidating low-temperature phenomena and ground state degeneracy, accurately quantifying residual entropy remains a formidable challenge due to significant computational hurdles. In this Letter, we introduce the Temperature Incremental Monte Carlo (TIMC) method, our novel solution crafted to surmount these challenges. The TIMC method incrementally calculates the partition function ratio of neighboring temperatures within Monte Carlo simulations, enabling precise entropy calculations and providing insights into a spectrum of other temperature-dependent observables in a single computational sweep of temperatures. We have rigorously applied TIMC to a variety of complex systems, such as the frustrated antiferromagnetic Ising model on both C60 and 2D triangular lattices, the Newman-Moore spin glass model, and a 2D quantum transverse field Ising model. Notably, our method surmounts the traditional obstacles encountered in partition function measurements when mapping $d$-dimensional quantum models to $d+1$-dimensional classical counterparts. The TIMC method's finesse in detailing entropy across the entire temperature range enriches our comprehension of critical phenomena in condensed matter physics. This includes insights into spin glasses, phases exhibiting spontaneous symmetry breaking, topological states of matter and fracton phases. Our approach not only advances the methodology for probing the entropic landscape of such systems but also paves the way for exploring their broader thermodynamic and quantum mechanical properties.Comment: 5 pages, 5 figure

Fine root morphology and growth in response to nitrogen addition through drip fertigation in a Populus × euramericana “Guariento” plantation over multiple years

International audienceAbstractKey messageNitrogen addition through drip fertigation to a poplar plantation (Populus × euramericana“Guariento”) promoted fine root growth only in the early period. The relationship between root growth and soil N content was positive in the first 2 years, but became negative in the third year when the soil N availability had substantially increased.ContextNitrogen (N) deficiency is common in forest soils, and N addition is sometimes applied in the case of intensive plantations. There is a need to better document the impact of N addition through the high-efficiency fertilization technique on fine root morphology and growth, given their importance for the uptake of nutrients and for tree growth.AimsWe aimed to quantitatively investigate the responses of fine roots in morphology and growth to N addition through surface drip fertigation over multiple years in a Populus × euramericana “Guariento” plantation.MethodsA field experiment that included four drip fertigation treatments with N addition levels (0, 60, 120, and 180 kg N ha−1 year−1) was conducted for three successive years. A coring method was used to sample soils and quantify the root morphological traits and soil N content along 0–60-cm profiles.ResultsThe root biomass density, length, surface area, specific length, and tissue density were significantly higher in the N addition treatments than those in the control after the first year, but the positive effect decreased in the second year. In the third year, root biomass in the N addition treatments was even lower by 11–39% than that in the control. The relationship between root growth and soil N content was also positive in the first 2 years and negative in the third year.ConclusionN addition promoted fine root growth mainly in the shallow soil and in the early period of experiment. The relationship between root growth and soil N content became negative in the third year when the soil N availability had substantially increased. It is suggested that fine roots adjust their growth and morphology in response to N availability varying along the soil profile and with the fertilization duration

X-Ray Repair Cross Complementing 4 (XRCC4) Genetic Single Nucleotide Polymorphisms and the Liver Toxicity of AFB1 in Hepatocellular Carcinoma

Our previous reports have shown that the genetic single-nucleotide polymorphisms (GSNPs) in the DNA repair gene X-ray repair cross complementing 4 (XRCC4) are involved in the carcinogenesis of hepatocellular carcinoma (HCC) induced by aflatoxin B1 (AFB1). However, the effects of GSNPs in the coding regions of XRCC4 on hepatic toxicity of AFB1 have been less investigated. We conducted a hospital-based clinic tissue samples with pathologically diagnosed HCC (n = 380) in a high AFB1 exposure area to explore the possible roles of GSNPs in the coding regions of XRCC4 in AFB1-induced HCC using liver toxicity assays. A total of 143 GSNPs were included in the present study and genotyped using the SNaPshot method, whereas the liver toxicity of AFB1 was evaluated using AFB1-DNA adducts in the tissues with HCC. In the clinicopathological samples with HCC, the average adduct amount is 2.27 ± 1.09 μmol/mol DNA. Among 143 GSNPs of XRCC4, only rs1237462915, rs28383151, rs762419679, rs766287987, and rs3734091 significantly increased the levels of AFB1-DNA adducts. Furthermore, XRCC4 GSNPs (including rs28383151, rs766287987, and rs3734091) also increased cumulative hazard for patients with HCC. These results suggest that the liver toxicity of AFB1 may be modified by XRCC4 GSNPs