6,750 research outputs found
Assembly Bias of Dwarf-sized Dark Matter Haloes
Previous studies indicate that assembly bias effects are stronger for lower
mass dark matter haloes. Here we make use of high resolution re-simulations of
rich clusters and their surroundings from the Phoenix Project and a large
volume cosmological simulation, the Millennium-II run, to quantify assembly
bias effects on dwarf-sized dark matter haloes. We find that, in the regions
around massive clusters, dwarf-sized haloes ([10^9,10^{11}]\ms) form earlier
( in redshift) and possess larger ()
than the field galaxies. We find that this environmental dependence is largely
caused by tidal interactions between the ejected haloes and their former hosts,
while other large scale effects are less important. Finally we assess the
effects of assembly bias on dwarf galaxy formation with a sophisticated
semi-analytical galaxy formation model. We find that the dwarf galaxies near
massive clusters tend to be redder () and have three times
as much stellar mass compared to the field galaxies with the same halo mass.
These features should be seen with observational data.Comment: 8 pages, 8 figures, accepted by MNRA
Local Freeway Ramp Metering using Self-Adjusted Fuzzy Controller
A self-adjusted fuzzy local ramp metering strategy is proposed to keep the mainline traffic state and the on-ramp queue length at reasonable levels. The fuzzy ramp metering strategy (FRMS) takes the following variables as inputs: error between desired density and measured density, change-in-error and on-ramp queue length. On-ramp metering flow is decided by these variables. It is difficult to construct fuzzy rules for a three-dimension inputs fuzzy controller based on expert knowledge, so the proposed FRMS generates fuzzy control rules by an analytic expression with correction factors. The correction factors reflect the weights upon linguistic variables of inputs and can be regulated according to actual traffic state of mainline and on-ramp. The proposed FRMS not only simplifies the process of rules definition for a multi-dimension fuzzy controller, but also has function of self-adjusted control rules. To examine the proposed FRMS, a freeway stretch in Los Angeles is simulated with distributed models. The proposed FRMS is also compared with an existing T-S FRMS and PI-ALINEA in the simulation experiments which cover different on-ramp inflow scenarios. Simulation results show the proposed FRMS provides improved adaptation to various scenarios and superiority in striking a balance between the mainline and on-ramp performances
Phase transitions and thermodynamics of the two-dimensional Ising model on a distorted Kagom\'{e} lattice
The two-dimensional Ising model on a distorted Kagom\'{e} lattice is studied
by means of exact solutions and the tensor renormalisation group (TRG) method.
The zero-field phase diagrams are obtained, where three phases such as
ferromagnetic, ferrimagnetic and paramagnetic phases, along with the
second-order phase transitions, have been identified. The TRG results are quite
accurate and reliable in comparison to the exact solutions. In a magnetic
field, the magnetization (), susceptibility and specific heat are studied by
the TRG algorithm, where the plateaux are observed in the magnetization
curves for some couplings. The experimental data of susceptibility for the
complex Co(N)(bpg) DMF are fitted with the TRG results,
giving the couplings of the complex and
Examining Physical Fitness and Training Strategies for Chinese Elite Canoe Slalom Players
Research showed that aerobic metabolism is one of the main energy supply for slalom athletes in training and competition (Jan Busta et al., 2018). To assist canoe slalom players improving their performance, it would be beneficial to examine the top canoe slalom athletesâ physical fitness status and their training protocols. By comparing the difference of the fitness status and training protocols, we may develop an optimal training protocol to improve the athletesâ physical fitness and their performance. In this study, the world top athletes and Chinese elite playersâ fitness status was compared. The goal was to help Chinese players to reach the top level in world competitions. Fifteen elite canoe slalom players were recruited from the Chinese national team (age: 21 ± 2 years; 3 female and12 male elite athletes). The fitness tests included bench push and bench pull for maximum strength(1RM) and endurance strength (40%1RM for 120 seconds). 300-meter speed race in flat water was used as a comparison indicator of athlete\u27s basic paddling speed ability, owing to the courses of slalom races differ. The physiology tests were VO2max, heart rate (HR) and blood lactate (BLA). All the data were collected during the winter training session in 2016. The HSIRB approved the data collection procedures. Descriptive statistics were calculated and analyzed using SPSS 25. The comparisons were made between Chinese elite athletes and world top athletes. For theVO2max/kg, the results showed that the Chinese elite canoe slalom female players (50.8 ± 2.19 ml/kg/min) fell 0.68 standard deviation (SD) lower than the world top level while males (56.03 ± 2.95ml/kg/min) fell 0.70SD lower. The maximum strength of bench push were 96 ± 4.1kg (female)and 125 ± 15.3kg (male). The bench pullwere81 ± 1.4kg (female) and 110 ± 5.8kg (male). The endurance strength repetition results of bench push were 91.3 ± 14.3 (female) and 80.8 ± 7.2 (male), the bench pull were 87 ± 6.7 (female) and 83.3 ± 7.6 (male). The result of 300-meter speed race in flat water showed that the Chinese male kayakers (100.1 ± 0.3s) was significantly slower than international male kayakers (88.1 ± 7.7s) (t = 1.56, p = 0.0594). Chinese male kayakersâ heart rate (170 ± 3 bpm, tested immediately) was slower and lactic acid level (15.4 ± 1.4 mmol/L, tested 3 minutes after) was higher, comparing with the world top kayakers. Chinese elite playersâ aerobic metabolism, strength and speed statistically fell behind of world top players in canoe slalom. In order to be competitive at the world top level race (e.g., 202 Tokyo Olympics), the Chinese elite canoe slalom players may need to add more proportion of aerobic training, endurance strength and speed training
Nonlinear fluorescence spectroscopy of layered perovskite quantum wells
Renewed interest in layered hybrid perovskite quantum wells is motivated by optoelectronic applications including photovoltaic devices, light-emitting diodes5, and microcavity lasers. Charges and energy can transfer between quantum wells with different levels, which is closely related to energy efficiency of the optical devices that include perovskites. In this paper, we fabricated a perovskite layered film that contained n=3 and n=4 quantum wells at a ratio of 1:1. We used the newly developed nonlinear fluorescence spectroscopy (NLFL) to determine that energy can simultaneously transfer from n=3 quantum wells to n=4 quantum wells, finally reaching the big quantum wells and detected as fluorescence emission by NLFL.Bachelor of Scienc
COMO A EDUCAĂĂO TRANSFORMA O MUNDO: EM HOMENAGEM AO CENTENĂRIO DE PAULO FREIRE
Trata-se de uma investigação sobre pontos de convergĂȘncia epistemolĂłgica e prĂĄtica educativa entre dois educadores, um chinĂȘs, Tao Xingzhi, e um brasileiro, Paulo Freire, com resultados bastante relevantes quanto Ă libertação de um povo oprimido, nĂŁo apenas em seus respectivos paĂses, mas por todo o mundo.This is an investigation into points of epistemological convergence and educational practice between two educators, one Chinese, Tao Xingzhi, and one Brazilian, Paulo Freire, with very relevant results regarding the liberation of an oppressed people, not only in their respective countries, but all over the world
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