RESUMEN

Joint species distribution modelling (JSDM) is a widely used statistical method that analyzes combined patterns of all species in a community, linking empirical data to ecological theory and enhancing community-wide prediction tasks. However, fitting JSDMs to large datasets is often computationally demanding and time-consuming. Recent studies have introduced new statistical and machine learning techniques to provide more scalable fitting algorithms, but extending these to complex JSDM structures that account for spatial dependencies or multi-level sampling designs remains challenging. In this study, we aim to enhance JSDM scalability by leveraging high-performance computing (HPC) resources for an existing fitting method. Our work focuses on the Hmsc R-package, a widely used JSDM framework that supports the integration of various dataset types into a single comprehensive model. We developed a GPU-compatible implementation of its model-fitting algorithm using Python and the TensorFlow library. Despite these changes, our enhanced framework retains the original user interface of the Hmsc R-package. We evaluated the performance of the proposed implementation across various model configurations and dataset sizes. Our results show a significant increase in model fitting speed for most models compared to the baseline Hmsc R-package. For the largest datasets, we achieved speed-ups of over 1000 times, demonstrating the substantial potential of GPU porting for previously CPU-bound JSDM software. This advancement opens promising opportunities for better utilizing the rapidly accumulating new biodiversity data resources for inference and prediction.

Asunto(s)

Algoritmos , Biología Computacional , Programas Informáticos , Biología Computacional/métodos , Modelos Biológicos , Aprendizaje Automático , Gráficos por Computador , Modelos Estadísticos , Humanos

RESUMEN

Electrochemical energy storage devices are ubiquitous for personal electronics, electric vehicles, smart grids, and future clean energy demand. SCs are EES devices with excellent power density and superior cycling ability. Herein, we focused on the fabrication and DFT calculations of Na3-δ-MnO2 nanocomposite, which has layered MnO2 redox-active sites, supported on carbon cloth. MnO2 has two-dimensional diffusion channels and is not labile to structural changes during intercalation; therefore, it is considered the best substrate for intercalation. Cation pre-intercalation has proven to be an effective way of increasing inter-layered spacing, optimizing the crystal structure, and improving the relevant electrochemical behavior of asymmetric aqueous supercapacitors. We successfully established Na+ pre-intercalated δ-MnO2 nanosheets on carbon cloth via one-pot hydrothermal synthesis. As a cathode, our prepared material exhibited an extended potential window of 0-1.4 V with a remarkable specific capacitance of 546 F g-1(300 F g-1 at 50 A g-1). Moreover, when this cathode was accompanied by an N-AC anode in an asymmetric aqueous supercapacitor, it illustrated exceptional performance (64 Wh kg-1 at a power density of 1225 W kg-1) and incomparable potential window of 2.4 V and 83% capacitance retention over 10,000 cycles with a great Columbic efficiency.

RESUMEN

A new type of chirality, orientational chirality, consisting of a tetrahedron center and a remotely anchored blocker, has been discovered. The key structural element of this chirality is characterized by multiple orientations directed by a through-space functional group. The multi-step synthesis of orientational chiral targets was conducted by taking advantage of asymmetric nucleophilic addition, Suzuki-Miyaura cross-coupling and Sonogashira coupling. An unprecedented catalytic species showing a five-membered ring consisting of C (sp2)-Br-Pd-C (sp2) bonds was isolated during performing Suzuki-Miyaura cross-coupling. X-ray diffraction analysis confirmed the species structure and absolute configuration of chiral orientation products. Based on X-ray structures, a model was proposed for the new chirality phenomenon to differentiate the present molecular framework from previous others. DFT computational study presented the relative stability of individual orientatiomers. This discovery would be anticipated to result in a new stereochemistry branch and to have a broad impact on chemical, biomedical, and material sciences in the future.

RESUMEN

Orientational chirality was discovered and characterized by a C(sp)-C(sp3) axis-anchored chiral center and a remotely anchored blocker. X-ray structural analysis proved that orientatiomers are stabilized by through-space functional groups, making it possible for 1 R- or S-chiral center to exhibit 3 orientational isomers simply by rotating operations. A new model system was proposed, fundamentally different from the traditional Felkin-Ahn-type or Cram-type models. In these traditional models, chiral C(sp3) center and blocking C(sp2) carbons are connected adjacently, and there exist 6 energy barriers during rotating along the C(sp2)-C(sp3) axis. In comparison, the present orientational chirality model shows that a chiral C(sp)-C(sp3) carbon is remotely located from a blocking group. Thus, it is focused on the steric dialog between a chiral C(sp3) center and a remotely anchored functional group. There exist 3 energy barriers for either (R)- or (S)-C(sp)-C(sp3) stereogenicity in the new model. Chiral amide auxiliary was proven to be an excellent chiral auxiliary in controlling rotations of orientatiomers to give complete stereoselectivity. The asymmetric synthesis of individual orientatiomers was conducted via multistep synthesis by taking advantage of the Suzuki-Miyaura cross-coupling and Sonogashira coupling reactions. Density functional theory computational study presented optimized conformers and relative energies for individual orientatiomers. This discovery would be anticipated to result in a new stereochemistry topic and have a broad impact on chemical, biomedical, and material sciences in the future.

RESUMEN

Chemical synthesis based on Group-Assisted Purification chemistry (GAP) has been prolifically used as a powerful, greener and ecofriendly tool so far. Herein, we report hypervalent iodine (III) mediated regio- and diastereoselective aminobromination of electron-deficient olefins using group-assisted purification (GAP) method. By simply mixing the GAP auxiliary-anchored substrates with TsNH2-NBS as nitrogen/bromine sources and PhI(OAc)2 as a catalyst, a series of vicinal bromoamines with multifunctionalities were obtained in moderate to excellent yields (53-94%). The vicinal bromoamines were obtained without column chromatography and/or recrystallization simply by washing the crude mixtures with cosolvents and thus avoiding wastage of silica, solvents, time, and labor. The GAP auxiliary is recyclable and reusable.

RESUMEN

Herein, we report a protocol for highly efficient hypervalent iodine (III) mediated, group-assisted purification (GAP) method for the regioselectivities and stereoselective aminochlorination of electron-deficient olefins. A series of vicinal chloramines with multifunctionalities were acquired in moderate to excellent yields (45-94%), by merely mixing the GAP auxiliary-anchored substrates with dichloramine T and tosylamide as chlorine/nitrogen sources and iodobenzene diacetate as a catalyst. The vicinal chloramines were obtained without any column chromatographic purification and recrystallization simply by washing the reaction mixture with a minimum amount of common inexpensive solvents and thus avoiding wastage of silica, solvents, time, and labor. The GAP auxiliary is recyclable and reusable. This strategy is easy to handle, cost-effective, greener, sustainable, environmentally benign, and mostly suitable for the syntheses of vicinal haloamines from various electron-deficient alkenes.

RESUMEN

A new Rh(III)-catalyzed [3 + 3] annulation reaction between cyclopropenones and ß-ketosulfoxonium ylides has been reported, enabling metal carbene insertion to access a wide range of trisubstituted 2-pyrones with moderate to excellent yields via C-C single-bond cleavage, in which sulfoxonium ylides serve as potential safe precursors of metal carbenes. This reaction occurred under redox-neutral conditions with a broad substrate scope.