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1.
Phys Rev Lett ; 132(7): 073202, 2024 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-38427885

RESUMO

The electric dipole moment (EDM) plays a crucial role in determining the interaction strength of an atom with electric fields, making it paramount to quantum technologies based on coherent atomic control. We propose a scheme for engineering the potential in a Paul trap to realize a two-level quantum system with a giant EDM formed by the motional states of a trapped electron. We show that, under realistic experimental conditions, our system exhibits enhanced EDMs compared to those attainable with Rydberg atoms, serving as a complementary counterpart in the megahertz (MHz) resonance-frequency range. Furthermore, we show that such artificial atomic dipoles can be efficiently initialized, read out, and coherently controlled, thereby providing a potential platform for quantum technologies such as ultrahigh-sensitivity electric-field sensing.

2.
J Therm Biol ; 119: 103799, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38342042

RESUMO

Epidemiological evidence shows that diabetic patients are susceptible to high temperature weather, and brown adipose tissue (BAT) activity is closely related to type 2 diabetes (T2DM). Activation of BAT under cold stress helps improve T2DM. However, the impact of high temperature on the activity of BAT is still unclear. The study aimed to investigate the impact of heat stress on glucose and lipid metabolism in T2DM mice by influencing BAT activity. High-fat feeding and injecting streptozotocin (STZ) induced model of T2DM mice. All mice were randomly divided into three groups: a normal(N) group, a diabetes (DM) group and a heat stress diabetes (DMHS) group. The DMHS group received heat stress intervention for 3 days. Fasting blood glucose, fasting serum insulin and blood lipids were measured in all three groups. The activity of BAT was assessed by using quantitative real-time PCR (qRT-PCR), electron microscopy, and PET CT. Furthermore, the UHPLC-Q-TOF MS technique was employed to perform metabolomics analysis of BAT on both DM group and DMHS group. The results of this study indicated that heat stress aggravated the dysregulation of glucose and lipid metabolism, exacerbated mitochondrial dysfunction in BAT and reduced the activity of BAT in T2DM mice. This may be related to the abnormal accumulation of branched-chain amino acids (BCAAs) in the mitochondria of BAT.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Humanos , Camundongos , Animais , Tecido Adiposo Marrom/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Experimental/metabolismo , Glucose/metabolismo , Metabolismo dos Lipídeos
3.
J Environ Manage ; 344: 118381, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37329579

RESUMO

This article introduces a simple, cost-saving and high efficient for the extraction and separation of microplastics (MPs) from soil with a high organic matter (SOM) content. In this study, MP with particle sizes of 154-600 µm of polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC) and polyethylene terephthalate (PET) were artificially added into the five Mollisols with the high SOM. Three flotation solutions were used to extract these MPs from soils, and four digestion solutions were used to digest the SOM. As well, their destruction effects on MPs were also examined. The results showed that the flotation recovery rates of PE, PP, PS, PVC and PET were 96.1%-99.0% by ZnCl2 solution, while were 102.0%-107.2% by rapeseed oil, were 100.0%-104.7% by soybean oil. The digestion rate of SOM was 89.3% by H2SO4:H2O2 (1:40, v:v) at 70 °C for 48 h, and this was higher than by H2O2 (30%), NaOH and Fenton's reagent. However, the digestion rate of PE, PP, PS, PVC and PET were 0.0%-0.54% by H2SO4:H2O2 (1:40, v:v), and this was lower than by H2O2 (30%), NaOH and Fenton's reagent. As well, the factors influencing on MP extraction was also discussed. Generally, the best flotation solution was ZnCl2 (ρ > 1.6 g cm-3) and the best digestion method was H2SO4:H2O2 (1:40, v:v) at 70 °C for 48 h. The optimal extraction and digestion method were verified by the known concentrations of MPs (recovery rate of MPs was 95.7-101.7%), and this method was also used to extract MPs from long-term mulching vegetable fields in Mollisols of Northeast China.


Assuntos
Microplásticos , Poluentes Químicos da Água , Peróxido de Hidrogênio , Plásticos , Solo , Descontaminação , Hidróxido de Sódio , Polipropilenos , Poliestirenos , Polietileno , Polietilenotereftalatos , Poluentes Químicos da Água/análise
4.
J Environ Manage ; 333: 117412, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36758402

RESUMO

Plastics production has been increasing over years, while their recycling rate is lower, resulting in huge amounts of microplastics (MP) accumulating in the environment. Although the environmental behaviors of MPs have been focused on in recent years, the migration, distribution and adverse effects of MPs in terrestrial and aquatic environments are still not systematically understood. In this review, based on the newest publications from the core database of the Web of Science, both the migration and distribution of MPs were summarized, as well as MPs transfer in biota and their biological effects were also focused on. Generally, the complicated and numerous pathways of MPs migration lead to their distribution throughout or nearly all environments on a global scale. However, the migration mechanisms of MPs with various sizes, shapes, and colors by physicochemical and biological processes, and the prediction models of MP migration and distribution, are deficient, despite these properties being highly related to MPs migration and bio-safety. Although MPs have already invaded microorganisms, plants, animals, and even human beings, the biological effects still need more study, so far as their sizes and shapes and also their composition and adsorption are concerned. Moreover, based on the highlights and deficiencies of current studies, further studies have also been proposed. This review aims to help people re-evaluate the uncertain behaviors of MPs in various environments, and could be helpful to fully understand their biological effects in different environmental conditions.


Assuntos
Microplásticos , Poluentes Químicos da Água , Animais , Humanos , Plásticos/química , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Biota
5.
Opt Express ; 30(13): 24048-24061, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-36225074

RESUMO

The higher-order topological insulator (HOTI) is a new type of topological system which has special bulk-edge correspondence compared with conventional topological insulators. In this work, we propose a scheme to realize Floquet HOTI with ultracold atoms in optical lattices. With the combination of periodically spin-dependent driving of the superlattices and a long-range coupling term, a Floquet second-order topological insulator with four zero-energy corner states emerges, whose Wannier bands are gapless and exhibit interesting bulk topology. Furthermore, the nearest-neighbor anisotropic coupling term also induced other intriguing topological phenomena, e.g. non-topologically protected corner states and topological semimetal for two different types of lattice structures respectively. Our scheme may give insight into the construction of different types of higher-order topological insulators in synthetic systems. It also provides an experimentally feasible platform to research the relations between different types of topological states and may have a wide range of applications in future.

6.
Opt Lett ; 46(1): 142-145, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33362036

RESUMO

A silicon-photonic tunable laser emitting two tunable wavelengths simultaneously is demonstrated. The laser consists of a single semiconductor optical amplifier that provides shared gain and a silicon-photonic chip that provides wavelength selections. A total optical power of 29.3 mW is shown, with 300 mA of gain current at 40°C. Continuous tuning of frequency spacing from 69.5 GHz to 114.1 GHz is demonstrated. The two simultaneous laser channels show highly correlated phase noise, with a phase noise correlation coefficient of 90.7%.

7.
Phys Rev Lett ; 126(1): 010502, 2021 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-33480770

RESUMO

Quantum criticality, as a fascinating quantum phenomenon, may provide significant advantages for quantum sensing. Here we propose a dynamic framework for quantum sensing with a family of Hamiltonians that undergo quantum phase transitions (QPTs). By giving the formalism of the quantum Fisher information (QFI) for quantum sensing based on critical quantum dynamics, we demonstrate its divergent feature when approaching the critical point. We illustrate the basic principle and the details of experimental implementation using quantum Rabi model. The framework is applicable to a variety of examples and does not rely on the stringent requirement for particular state preparation or adiabatic evolution. It is expected to provide a route towards the implementation of criticality-enhanced quantum sensing.

8.
J Environ Manage ; 299: 113704, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34523538

RESUMO

Natural vegetation restoration (NVR) highly relates to the development of gully erosion, and is mainly determined by both the soil properties and species competition in the gullies. However, it is still not clear what are the key factors influencing on the vegetation restoration in the gullies with the poor soil properties (e.g. low soil organic matter and nutrients) under the special hydrological process (e.g. high runoff intensity and long flow duration). In this study, soil total organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), total phosphorus (TP), available phosphorus (AP), pH, soil moisture (SM) were investigated, and both regression and structural equation model analysis were used for detecting how soil properties and species competition influence the herbaceous plants restoration in the poor quality of Mollisols in gullies of Northeast China. The results show that, (1) influence of NH4+-N, AN, TN, pH on biomass was stronger in 0-10 cm than that in 10-20 cm soil depth, opposite was stronger in 10-20 cm than that in 0-10 cm soil depth for NO3--N, SOC and SM (P < 0.05). (2) NH4+-N, NO3--N, AN, TN, SOC, pH, C:N were all negative, while SM was positive to plant biodiversity in soil layers (P < 0.05). (3) SOM mainly mediates the TN and NH4+-N and then directly or indirectly influences on biodiversity and biomass, and P changed the species richness when AP >20 mg kg-1 in 10-20 cm soil depth. (4) Vegetation restoration was mainly determined by the dynamics of Elymus dahuricus Turcz. firstly, and then by Leymus chinensis(Trin.) Tzvel. at the early of vegetation restoration. Generally, the heterogeneity of SOC and SM in soil layers and AP in deep soil layer was the key factors determining NVR in the gullies of Mollisols watershed. At the end of paper, the NVR process in Moillosols in gullies was classified as four stages, and each stage was depicted in detail.


Assuntos
Carbono , Nitrogênio , Nitrogênio/análise , Fósforo , Plantas , Solo
9.
Phys Rev Lett ; 123(26): 260405, 2019 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-31951424

RESUMO

Synthetic spaces allow physicists to bypass constraints imposed by certain physical laws in experiments. Here, we show that a synthetic torus, which consists of a ring trap in the real space and internal states of ultracold atoms cyclically coupled by Laguerre-Gaussian Raman beams, could be threaded by a net effective magnetic flux through its surface-an impossible mission in the real space. Such a synthetic Hall torus gives rise to a periodic lattice in real dimensions, in which the periodicity of the density modulation of atoms fractionalizes that of the Hamiltonian. Correspondingly, the energy spectrum is featured by multiple bands grouping into clusters with nonsymmorphic-symmetry-protected band crossings in each cluster, leading to swaps of wave packets in Bloch oscillations. Our scheme allows physicists to glue two synthetic Hall tori such that localization may emerge in a quasicrystalline lattice. If the Laguerre-Gaussian Raman beams and ring traps were replaced by linear Raman beams and ordinary traps, a synthetic Hall cylinder could be realized and deliver many of the aforementioned phenomena.

10.
Phys Rev Lett ; 121(21): 210501, 2018 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-30517807

RESUMO

We experimentally observe Floquet Raman transitions in the weakly driven solid-state spin system of a nitrogen-vacancy center in diamond. The periodically driven spin system simulates a two-band Wannier-Stark ladder model and allows us to observe coherent spin state transfer arising from a Raman transition mediated by Floquet synthetic levels. It also leads to the prediction of an analog photon-assisted Floquet Raman transition and dynamical localization in a driven two-level quantum system. The demonstrated rich Floquet dynamics offers new capabilities to achieve effective Floquet coherent control of a quantum system with potential applications in various types of quantum technologies based on driven quantum dynamics. In particular, the Floquet Raman system may be used as a quantum simulator for the physics of periodically driven systems.

11.
J Sports Sci ; 36(22): 2511-2520, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29676222

RESUMO

The aim of this study was: (i) to group basketball players into similar clusters based on a combination of anthropometric characteristics and playing experience; and (ii) explore the distribution of players (included starters and non-starters) from different levels of teams within the obtained clusters. The game-related statistics from 699 regular season balanced games were analyzed using a two-step cluster model and a discriminant analysis. The clustering process allowed identifying five different player profiles: Top height and weight (HW) with low experience, TopHW-LowE; Middle HW with middle experience, MiddleHW-MiddleE; Middle HW with top experience, MiddleHW-TopE; Low HW with low experience, LowHW-LowE; Low HW with middle experience, LowHW-MiddleE. Discriminant analysis showed that TopHW-LowE group was highlighted by two-point field goals made and missed, offensive and defensive rebounds, blocks, and personal fouls; whereas the LowHW-LowE group made fewest passes and touches. The players from weaker teams were mostly distributed in LowHW-LowE group, whereas players from stronger teams were mainly grouped in LowHW-MiddleE group; and players that participated in the finals were allocated in the MiddleHW-MiddleE group. These results provide alternative references for basketball staff concerning the process of evaluating performance.


Assuntos
Desempenho Atlético/fisiologia , Basquetebol/fisiologia , Estatura , Peso Corporal , Análise por Conglomerados , Humanos , Masculino , Destreza Motora/fisiologia
12.
J Environ Manage ; 204(Pt 1): 170-178, 2017 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-28881326

RESUMO

Laboratory experiments were conducted to investigate the efficiency of a simultaneous chemical extraction and oxidation for removing persistent organic pollutants (POPs) and toxic metals from an actual soil polluted by the recycling activity of electronic waste. Various chemicals, including hydroxypropyl-ß-cyclodextrin (HPCD), citric acid (CA) and sodium persulfate (SP) were applied synchronously with Fe2+ activated oxidation to enhance the co-removal of both types of pollutants. It is found that the addition of HPCD can enhance POPs removal through solubilization of POPs and iron chelation; while the CA-chelated Fe2+ activation process is effective for extracting metals and degrading residual POPs. Under the optimized reagent conditions, 69.4% Cu, 78.1% Pb, 74.6% Ni, 97.1% polychlorinated biphenyls, 93.8% polycyclic aromatic hydrocarbons, and 96.4% polybrominated diphenylethers were removed after the sequential application of SP-HPCD-Fe2+ and SP-CA-Fe2+ processes with a duration of 180 and 240 min, respectively. A high dehalogenation efficiency (84.8% bromine and 86.2% chlorine) is observed, suggesting the low accumulation of halogen-containing organic intermediates. The remediated soil can satisfy the national soil quality standard of China. Collectively, co-contaminated soil can be remediated with reasonable time and capital costs through simultaneous application of persulfate oxidation and chemical extraction.


Assuntos
Quelantes/química , Ácido Cítrico/química , Resíduo Eletrônico , Bifenilos Policlorados/química , Compostos de Sódio/química , Poluentes do Solo/análise , Sulfatos/química , China , Recuperação e Remediação Ambiental , Oxirredução , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos , Reciclagem , Compostos de Sódio/análise , Poluentes do Solo/química , Sulfatos/análise
13.
Phys Rev Lett ; 116(4): 045301, 2016 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-26871339

RESUMO

A unique feature of ultracold atoms is the separation of length scales, r_{0}≪k_{F}^{-1}, where k_{F} and r_{0} are the Fermi momentum characterizing the average particle distance and the range of interaction between atoms, respectively. For s-wave scattering, Shina Tan discovered that such diluteness leads to universal thermodynamic relations governed by contact. Here, we show that the concept of contact can be generalized to an arbitrary partial-wave scattering. Contact of all partial-wave scatterings forms a contact spectrum, which establishes universal thermodynamic relations with notable differences from those in the presence of s-wave scattering alone. Such a contact spectrum is particularly useful for characterizing many-body correlations in atomic quantum Hall states (QHSs). It has an interesting connection with a special bipartite entanglement spectrum of QHSs and enables an intrinsic probe of atomic QHSs using short-range two-body correlations.

14.
Inorg Chem ; 55(21): 10859-10869, 2016 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-27715039

RESUMO

We herein reported the synthetic, structural, computational, and magnetic studies of four air-stable heptacoordinated mononuclear cobalt(II) complexes, namely, [CoII(tdmmb)(H2O)2][BF4]2 (1), [CoII(tdmmb)(CN)2]·2H2O (2), [CoII(tdmmb)(NCS)2] (3), and [CoII(tdmmb)(SPh)2] (4) (tdmmb = 1,3,10,12-tetramethyl-1,2,11,12-tetraaza[[3](2,6)pyridino[3](2,9)-1,10-phenanthrolinophane-2,10-diene; SPh- = thiophenol anion). Constrained by the rigid pentadentate macrocyclic ligand tdmmb, the CoII centers in all of these complexes are in the heptacoordinated pentagonal-bipyramidal geometry. While the equatorial environments of these complexes remain very similar to each other, the axial ligands are systematically modified from C to N to O to S atoms. Analyses of the magnetic data and the ab initio calculations both reveal large easy-plane magnetic anisotropy (D > 0) for all four complexes. While the experimentally obtained D values do not show any clear tendency when the axial coordinated atoms change from C to N to O atoms (complexes 1-3), the largest value is for the heavier and softer S-atom-coordinated complex 4. Because of significant magnetic anisotropy, all four complexes are field-induced single-ion magnets. This work represents a delicate modification of the magnetic anisotropy by tuning the chemical environment of the metal centers.

15.
Phys Rev Lett ; 115(22): 225301, 2015 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-26650309

RESUMO

A chiral d-wave superfluid is a preliminary example of interacting topological matter. However, unlike s-wave superfluids prevalent in nature, its existence requires a strong d-wave interaction, a criterion that is difficult to access in ordinary systems. There is no experimental observation of such unconventional superfluid at the moment. Here, we present a new principle for creating a two-dimensional (2D) chiral d-wave superfluid using periodically driven lattices. Because of an imprinted 2D pseudospin-orbit coupling, where the sublattice index serves as the pseudospin, the s-wave interaction between two hyperfine spin states naturally creates a chiral d-wave superfluid. This scheme can be directly implemented in current experiments.

16.
Inorg Chem ; 54(16): 7857-67, 2015 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-26212932

RESUMO

Three mononuclear spin crossover (SCO) compounds [Fe(2-pic)3]·A2·Solv (A = m-ABS(-), Solv = MeOH, 1; A = p-ABS(-), 2; A = OTf(-), 3) were prepared and characterized magnetically and structurally (2-pic = 2-picolylamine, m-HABS = m-aminobenzenesulfonic acid, p-HABS = p-aminobenzenesulfonic acid, HOTf = trifluoromethanesulfonic acid). Single-crystal X-ray analyses show that they are constructed from the charge-assisted hydrogen bonds between the 2-pic donors and the organosulfonate acceptors, forming the hydrogen-bonded three-dimensional networks for 1 and 2 and one-dimensional columns for 3. While the [Fe(2-pic)3](2+) cations in compounds 1 and 2 are in the meridional (mer-) configuration, it has a facial (fac-) configuration in complex 3. Magnetic susceptibility measurements revealed the SCO transitions and the SCO properties in all three complexes are quite different. Compound 1 undergoes an abrupt SCO with critical temperatures T1/2↓ = 100 K and T1/2↑ = 103 K, while compound 2 exhibits a gradual SCO with T1/2 = 218 K. Compound 3, with the fac-configuration, has an abrupt SCO transition accompanied by the structural phase transition with critical temperatures T1/2↓ = 333 K and T1/2↑ = 343 K. The SCO transitions were further confirmed by the detailed structural analyses of the coordination environments of the Fe(II) centers in both spin states and also by differential scanning calorimetry. Compared to the famous [Fe(2-pic)3]·A2·Solv compounds in the literature, compound 2 has the highest transition temperature for the mer-[Fe(2-pic)3](2+)-containing compounds, while compound 3 represents the first example of the structurally characterized compound of the fac-[Fe(2-pic)3](2+) motif showing SCO behavior. These results show that the organosulfonate anions are very promising to adjust the hydrogen-bonded structures of the SCO compounds and improve the SCO properties of those structures.

17.
World J Microbiol Biotechnol ; 31(11): 1755-63, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26296414

RESUMO

The aim of this study was to analyze the changes of soil microbial communities stimulated by climate, soil type and vegetation type using a functional gene array. The dataset GSE51592 was obtained from Gene Expression Omnibus, including 54 soil samples. Genetic diversity variation of samples under different sites, soil and vegetation types was examined by calculating the percentage of specific gene number in each sample. Furthermore, gene functional categories and microorganism species in samples under different environmental factors were respectively divided. Gene number in samples with cropping was higher than in samples without cropping. When site, soil type and vegetation type were as the sole variable, respectively, the percentage of specific genes in samples from Yingtan, in phaeozem samples and in samples with cropping was higher. Furthermore, the percentage of gene number in organic remediation for phaeozem and cambisol samples was significant at p < 0.05, comparing with that for acrisol samples. At superkingdom level of microorganisms, for the same category, there was no significant difference (p < 0.05) between the samples. At phylum level, for the categories of Bacteroidetes and Cyanobacteria, the percentage of gene number in cambisol samples was significantly higher (p < 0.05). Conversely, in the category of Proteobacteria, the percentage of gene number in phaeozem and acrisol samples was markedly higher (p < 0.05). Microbial diversity of soil was cooperatively driven by climate, soil type and vegetation type.


Assuntos
Bactérias/classificação , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Plantas/classificação , Microbiologia do Solo , Solo/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Biodiversidade , Clima , Dosagem de Genes , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos , Consórcios Microbianos
18.
Yao Xue Xue Bao ; 50(8): 1021-5, 2015 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-26669003

RESUMO

Photodynamic therapy (PDT), because of its good targeting, minimal invasion, and safety, is becoming a very active area in cancer prevention and treatment, in which the photosensitizers have proved to be the core element for PDT. We developed a new HPLC method for analyzing porphyrin photosensitizers using Shiseido Capcell PAK C18 (150 mm x 4.6 mm, 5 µm) as the column at 30 °C, methanol-1% aqueous solution of acetic acid as the mobile phase in a flow rate of 1.0 mL · min(-1) in a gradient elution mode, and the detection wavelength at 380 nm. This method, showing good specificity, precision, accuracy and robusty via methodology validations, can be applied to the purity test and assay of porphyrin photosensitizers, and has played a key guide role in the R&D of the new porphyrin photosensitizer--sinoporphyrin sodium.


Assuntos
Cromatografia Líquida de Alta Pressão , Fármacos Fotossensibilizantes/química , Porfirinas/química , Fotoquimioterapia
19.
Front Psychol ; 15: 1412840, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38947912

RESUMO

In competitive sports, momentum encompasses positive or negative changes in cognition, physiology, emotions, and behavior caused by sudden or a series of continuous events. Momentum occurring during basketball games leads to significant performance variation regarding positive net points differences for a specific team within a certain period. This study designed a quantitative framework based on two performative dimensions (time constraints and point differentials) to accurately identify momentum in basketball games, and explored the role of momentum in games. We identified 2,083 momentum occurrences in 372 professional elite basketball games. The number of momentum occurrences for winning teams is significantly higher than for losing teams (1.78 ± 0.47 Difference Value, p < 0.001); the correlation between momentum and game outcomes decreased as each quarter progressed. To distinguish the influence of contextual variables on momentum, we divided games into five types based on the team quality differences between the team and the opponent team. The decision tree model shows that first-quarter momentum is critical in games where weaker teams defeat stronger teams. This study provides insights for basketball coaches to formulate game strategies. More importantly, the momentum conceptual framework can help researchers identify and capture momentum, offering inspiration and reference for subsequent research.

20.
Sports Med ; 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38814566

RESUMO

BACKGROUND AND OBJECTIVE: Understanding and recognizing basketball offensive set plays, which involve intricate interactions between players, have always been regarded as challenging tasks for untrained humans, not to mention machines. In this study, our objective is to propose an artificial intelligence model that can automatically recognize offensive plays using a novel self-supervised learning approach. METHODS: The dataset was collected by SportVU from 632 games during the 2015-2016 season of the National Basketball Association (NBA), with a total of 90,524 possessions. A multi-agent motion prediction pretraining model was built on the basis of axial-attention transformer and trained with different masking strategies: motion prediction (MP), motion reconstruction (MR), and MP + MR joint strategy. A downstream play-level classification task and similarity search were used to evaluate the models' performance. RESULTS: The results showed that the MP + MR joint masking strategy maximized the ability of the model compared with individual masking strategies. For the classification task, the joint strategy achieved a top-1 accuracy of 81.5% and top-3 accuracy of 97.5%. In the similarity search evaluation, the joint strategy attained a top-5 accuracy of 76% and top-10 accuracy of 59%. Additionally, with the same MP + MR joint masking strategy, our HoopTransformer model outperformed the two baseline models in the classification task and similarity search. CONCLUSION: This study presents a self-supervised learning model and demonstrates the effectiveness and potential of the model in accurately comprehending and capturing player movements and complex interactions during offensive plays.

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