We describe the implementation details of periodic local coupled-cluster theory with single and double excitations (CCSD) and perturbative triple excitations [CCSD(T)] using local natural orbitals (LNOs) and -point symmetry. We discuss and compare several choices for orbital localization, fragmentation, and LNO construction. By studying diamond and lithium, we demonstrate that periodic LNO-CC theory can be applied with equal success to both insulators and metals, achieving speedups of 2 to 3 orders of magnitude even for moderately sized -point meshes. Our final predictions of the equilibrium cohesive energy, lattice constant, and bulk modulus for diamond and lithium are in good agreement with previous theoretical predictions and experimental results.
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Sci Rep
December 2024
Key Laboratory of Computing Power Network and Information Security, Shandong Computer Science Center (National Supercomputing Center in Jinan), Ministry of Education, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250013, Shandong, P. R. China.
Crystal structure similarity is useful for the chemical analysis of nowadays big materials databases and data mining new materials. Here we propose to use two-dimensional Wasserstein distance (earth mover's distance) to measure the compositional similarity between different compounds, based on the periodic table representation of compositions. To demonstrate the effectiveness of our approach, 1586 Cu-S based compounds are taken from the inorganic crystal structure database (ICSD) to form a validation dataset.
View Article and Find Full Text PDFNat Commun
December 2024
School of Materials Science and Engineering, Peking University, Beijing, 100871, China.
Crystal symmetry, which governs the local atomic coordination and bonding environment, is one of the paramount constituents that intrinsically dictate materials' functionalities. However, engineering crystal symmetry is not straightforward due to the isotropically strong covalent/ionic bonds in crystals. Layered two-dimensional materials offer an ideal platform for crystal engineering because of the ease of interlayer symmetry operations.
View Article and Find Full Text PDFEcol Lett
December 2024
Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, USA.
Relations among territoriality, abundance and habitat suitability are fundamental to the ecology of many animal populations. Theory suggests two classes of possible responses to increasing abundance in territorial species: (1) the ideal free distribution (IFD), which predicts smaller territory sizes and decreased fitness as individuals adaptively pack into suitable habitats, and (2) the ideal despotic distribution (IDD), which predicts stable territory sizes and fitness in preferred habitats for dominant individuals and increased use of marginal habitats, reduced fitness and changes in territory sizes for subordinate individuals. We analysed the territory sizes and locations of seven migratory songbird species occupying a 10-ha plot in the Hubbard Brook Experimental Forest, New Hampshire, USA over a 52-year period.
View Article and Find Full Text PDFHead Neck
December 2024
Department of Pediatric Hematology & Oncology, Klinik für Kinder- Und Jugendmedizin, Universitätsmedizin Rostock, Rostock, Germany.
Background: Infantile fibrosarcoma (IFS) is a rare pediatric tumor of intermediate malignancy with high local aggressiveness that typically presents in young infants. Its occurrence in the head and neck region is rare. Complete non-mutilating surgical resection is often not possible, requiring multimodal treatment.
View Article and Find Full Text PDFcolorectal cancer is a common and serious condition, with surgical resection being the primary treatment for localized cases. Anastomotic dehiscence (AD) remains a significant postoperative complication, and anastomoses are typically created using either manual suturing or mechanical stapling, each with specific benefits and challenge. Material and this retrospective study analyzed outcomes in 100 rectal cancer patients who underwent surgical resection, with anastomoses performed via manual suturing (n=50) or mechanical stapling (n=50).
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