Interaction of Acidithiobacillus ferrooxidans , Rhizobium phaseoli and Rhodotorula sp. in bioleaching process based on Lotka\u2013Volterra model

Background: Nowadays, leaching-ore bacteria, especially Acidithiobacillus ferrooxidans is widely used to retrieve heavy metals, many researches reflected that extra adding microorganism could promote bioleaching efficiency by different mechanisms, but few of them discussed the interaction between microorganisms and based on growth model. This study aimed to provide theoretical support for the collaborative bioleaching of multiple microorganisms by using the Lotka\u2013Volterra (L\u2013V) model. Results: This study investigated the interaction of Acidithiobacillus ferrooxidans, Rhizobium phaseoli, and Rhodotorula sp. Results showed that the individual growth of the three microorganisms fit the logistic curves. The environmental capacities of A. ferrooxidans, R. phaseoli, and Rhodotorula sp. were 1.88 7 109, 3.26 7 108, and 2.66 7 108 cells/mL, respectively. Co-bioleaching showed mutualism between A. ferrooxidans and R. phaseoli with mutualism coefficients of \u3b1 = 1.19 and \u3b2 = 0.31, respectively. The relationship between A. ferrooxidans and Rhodotorula sp. could be considered as commensalism. The commensalism coefficient \u3b3 of the effect of Rhodotorula sp. on A. ferrooxidans was 2.45. The concentrations of A. ferrooxidans and R. phaseoli were 3.59 7 109 and 1.44 7 109 cells/mL in group E, respectively, as predicted by the model. The concentrations of A. ferrooxidans and Rhodotorula sp. were 2.38 7 109 and 2.66 7 108 cells/mL, respectively. The experimental peak values of the concentrations in microorganism groups E and F were detected on different days, but were quite close to the predicted values. Conclusion: The relationship among microorganisms during leaching could be described appropriately by Lotka\u2013 Volterra model between the initial and peak values. The relationship of A. ferrooxidans and R. phaseoli could be considered as mutualism, whereas, the relationship of A. ferrooxidans and R. phaseoli could be considered as commensalism

Status Analysis and Consideration of Medical Education System in China and Abroad

This paper concludes five current medical education systems by investigating medical education status in both China and abroad. They are: 5+3 years British system, 6-year German system, 6-year Russian system, “4+4” years American system, and 5+3+3 years Chinese system. Based on the five systems, this paper analyzes the current situation of medical postgraduate student education of the Great Britain, Germany, U.S.A, France, and China. In the last part of this paper, a careful consideration on Chinese medical education is made. Authors of this paper suggest that China should gradually call off multi-level medical education; take 8-year, 5-year, and 5+4 years education as the principal modes of medical education. Students should be offered medical doctor’s degree and positioned as diplomates after the 8-year medical education. Students who finish the 5-year medical education will be awarded the bachelor’s degree and work as general practitioner. Students decide to receive another 4 years medical education after finishing the 5-year one will be granted medical doctor’s degree (diplomate or general practitioner). The 3-year medical postgraduate education should be gradually abolished.Key words: Medical education; Postgraduate education; Education syste

Stability and Mechanical Properties of w1-X Mox b4.2 (X=0.0-1.0) From First Principles

Heavy transition-metal tetraborides (e.g., tungsten tetraboride, molybdenum tetraboride, and molybdenum-doped tungsten tetraboride) exhibit superior mechanical properties, but solving their complex crystal structures has been a long-standing challenge. Recent experimental x-ray and neutron diffraction measurements combined with first-principles structural searches have identified a complex structure model for tungsten tetraboride that contains a boron trimer as an unusual structural unit with a stoichiometry of 1:4.2. In this paper, we expand the study to binary MoB4.2 and ternary W1-xMoxB4.2 (x=0.0-1.0) compounds to assess their thermodynamic stability and mechanical properties using a tailor-designed crystal structure search method in conjunction with first-principles energetic calculations. Our results reveal that an orthorhombic MoB4.2 structure in Cmcm symmetry matches well the experimental x-ray diffraction patterns. For the synthesized ternary Mo-doped tungsten tetraborides, a series of W1-xMoxB4.2 structures are theoretically designed using a random substitution approach by replacing the W to Mo atoms in the Cmcm binary crystal structure. This approach leads to the discovery of several W1-xMoxB4.2 structures that are energetically superior and stable against decomposition into binary WB4.2 and MoB4.2. The structural and mechanical properties of these low-energy W1-xMoxB4.2 structures largely follow the Vegard\u27s law. Under changing composition parameter x=0.0-1.0, the superior mechanical properties of W1-xMoxB4.2 stay in a narrow range. This unusual phenomenon stems from the strong covalent network with directional bonding configurations formed by boron atoms to resist elastic deformation. The findings offer insights into the fundamental structural and physical properties of ternary W1-xMoxB4.2 in relation to the binary WB4.2/MoB4.2 compounds, which open a promising avenue for further rational optimization of the functional performance of transition-metal borides that can be synthesized under favorable experimental conditions for wide applications

Towards Consistent Video Editing with Text-to-Image Diffusion Models

Existing works have advanced Text-to-Image (TTI) diffusion models for video editing in a one-shot learning manner. Despite their low requirements of data and computation, these methods might produce results of unsatisfied consistency with text prompt as well as temporal sequence, limiting their applications in the real world. In this paper, we propose to address the above issues with a novel EI$^2$ model towards \textbf{E}nhancing v\textbf{I}deo \textbf{E}diting cons\textbf{I}stency of TTI-based frameworks. Specifically, we analyze and find that the inconsistent problem is caused by newly added modules into TTI models for learning temporal information. These modules lead to covariate shift in the feature space, which harms the editing capability. Thus, we design EI$^2$ to tackle the above drawbacks with two classical modules: Shift-restricted Temporal Attention Module (STAM) and Fine-coarse Frame Attention Module (FFAM). First, through theoretical analysis, we demonstrate that covariate shift is highly related to Layer Normalization, thus STAM employs a \textit{Instance Centering} layer replacing it to preserve the distribution of temporal features. In addition, {STAM} employs an attention layer with normalized mapping to transform temporal features while constraining the variance shift. As the second part, we incorporate {STAM} with a novel {FFAM}, which efficiently leverages fine-coarse spatial information of overall frames to further enhance temporal consistency. Extensive experiments demonstrate the superiority of the proposed EI$^2$ model for text-driven video editing

High time-resolution analytical models for heat transfer through U-shaped ground heat exchangers

This paper reports a set of high time-resolution analytical models for heat transfer of GHEs, including a full scale line-source model for heat transfer outside U-shaped pipes and a quasi-3D heat transfer model for the circulating fluid inside U-shaped pipes. The full scale line-source model is a composite expression consisting of a composite medium line-source solution for short-term temperature responses, an infinite line-source solution for mid-term temperature responses, a finite line-source solution for long-term temperature responses, and a finite line-source solution for the thermal interaction between adjacent boreholes. The quasi-3D model for heat transfer inside U-pipes tackles the variation of the fluid temperature along the U-shaped channels. The fluid temperatures in the descending and ascending legs are derived as functions of time and borehole depth. The quasi-3D model, together with the full scale G-function, constitutes a complete theoretical model for heat transfer by ground heat exchangers, providing a computational-efficient approach to computer simulation, analysis, and optimum design of ground-coupled heat pump and ground heat storage systems