Quantitative assessment of ecological operation effects based on flood pulses and ecology-economic coupling model: a case study of Three Gorges Reservoir, China

Flood pulses are closely related to river ecosystem health. Reservoirs bring many benefits to flood control, power generation, shipping etc., but their attenuation effects on runoff flood pulses should not be ignored. Ecological operation can effectively reduce some negative ecological impacts brought by the reservoir. However, the inability to quantitatively assess ecological effects hinders the promotion of ecological operation in reservoir management. To solve this problem, we proposed 11 flood pulse indicators (FPI), a random simulation method and an ecology-economy coupling model in this study. In addition, we used four major Chinese carps as indicator species and the Three Gorges Reservoir as a case study to test the role of flood pulses in improving the ecological operation effects of the reservoir from the fish protection perspective. The results show that: (1) FPI can be controlled by the reservoir and reflect the flood pulse characteristics of runoff. (2) Random simulation method guides managers to optimize the discharge and formulate eco-friendly operation schemes. (3) Ecology-economy coupling model helps managers analyze the relationship between ecological operation effects and economic benefits. A comprehensive assessment can improve the acceptance of ecological operation, which is conducive to the sustainable development of river ecosystem.

Application of Random Dynamic Grouping Simulation Algorithm in PE Teaching Evaluation

The probability ranking conclusion is an extension of the absolute form evaluation conclusion. Firstly, the random simulation evaluation model is introduced; then, the general idea of converting the traditional evaluation method to the random simulation evaluation model is analyzed; on this basis, based on the rule of “further ensuring the stability of the ranking chain on the basis of increasing the possibility of the ranking chain,” two methods of solving the probability ranking conclusion are given. Based on the rule of “further guaranteeing the stability of the ranking chain on the basis of improving the likelihood of the ranking chain,” two methods are given to solve the likelihood conclusion. This paper argues that this absolute form of conclusion hinders the approximation of the theory to the essence of the actual problem and is an important reason for the problem of “non-consistency of multi-evaluation conclusions.” To address this problem, a stochastic simulation-based comprehensive evaluation solution algorithm based on the idea of “Monte Carlo simulation” is proposed, and the corresponding ranking method is investigated, which is characterized by generating evaluation conclusions with probability (reliability) information, and thus has more advantages than the absolute conclusion form in terms of problem interpretability. The method is characterized by the generation of evaluation conclusions with probabilistic (reliability) information and thus has more advantages than the absolute conclusion form in terms of problem interpretation. Because of the independence of the stochastic simulation solution method, it is applied to the “bottom-up” evaluation model as an example, and a novel autonomous evaluation method is constructed. Finally, the application of the stochastic simulation evaluation model is illustrated by an example and compared with the absolute form evaluation. The evaluation model is an extension of the traditional evaluation model, which can further broaden the practical application of comprehensive evaluation theory.

In Situ Fate Mapping of Native and Stress Myelopoiesis Reveals a Unique Niche for Mono- and Dendritic Cell -Poiesis

In contrast to virtually all other tissues in the body the anatomy of differentiation in the bone marrow remains unknown. This is due to the lack of strategies to examine blood cell production in situ, which are required to better understand differentiation, lineage commitment decisions, and to define how spatial organizing cues inform tissue function. We developed approaches to image and fate map -using confetti mice- myelopoiesis in situ and generated 3D atlases of granulocyte and monocyte/dendritic cell differentiation during homeostasis and after emergency myelopoiesis induced by infection with Listeria monocytogenes. Figure 1 shows stepwise differentiation during myelopoiesis. We have found that -in imaging studies- CD11b-Ly6C-CD117+CD115+ cells are MDP; Lin-CD117+CD16/32+CD115- cells are GMP; CD11b-Ly6C+CD117+CD115+ are MOP; CD11b-CD117+CD115-Ly6C+ are GP; CD11b+CD115+Ly6Chi and CD11b+CD115+Ly6Clo cells are Ly6Chi and Ly6Clo monocytes; and MHCIIhi reticular cells are dendritic cells (DC). We used these markers to map every myeloid cell in the sternum and assessed the relationships between myeloid progenitors, their offspring and candidate niches in situ with single cell resolution. To test whether the interactions observed were specific we obtained the X, Y and Z coordinates for every hematopoietic cell in the sternum (detected using αCD45 and αTer119). We then used these coordinates to randomly place each type of myeloid cell, at the same frequencies found in vivo, through the BM to generate random distributions for each myeloid cell type. We found that myeloid progenitors do not localize with HSC indicating that they leave the HSC niche during differentiation. In the steady-state GP, MOP, and MDP are found as single cells that do not associate with each other indicating that granulo-, mono-, and dendritic cell-poiesis take place in different location. Myeloid progenitors are specifically recruited to sinusoids but are depleted near endosteum and arterioles (e.g. mean MDP distance to sinusoids, arterioles, and endosteum observed 5, 134, and 105μm vs 9, 86, and 69µm in the random simulation). GP form clusters with preneutrophils and immature neutrophils, in situ fate mapping demonstrated that these clusters are oligoclonal and that additional GP are serially recruited to the cluster as the old ones differentiate. Ly6Clo monocytes and dendritic cells are selectively enriched near MDP (2.0 DC and 4.4 Ly6Clo monocytes observed within 50µm of an MDP vs 0.9 DC and 1.8 Ly6Clo monocytes in the random simulation p=0.02 and p<0.0001). Fate mapping experiments demonstrated that the monocytes around MOP and monocytes and dendritic cells around the MDP are oligoclonal but are not the derived from the MOP/MDP they associate with. These indicate that Ly6Clo monocytes and DC are produced elsewhere but are then selectively recruited to regions enriched in MDP. The results above suggest that different sinusoids might be responsible for supporting different myeloid lineages. We found that dendritic cells localize to a unique subset (8% of all vessels) of colony stimulating factor 1 (CSF1, the major regulator of monopoiesis) -expressing sinusoids. Csf1 deletion in the vasculature disrupted MDP interaction with sinusoids, leading to reduced MDP numbers and differentiation ability, with subsequent loss of Ly6Clo monocytes and dendritic cells. L. monocytogenes infection dramatically changed the architecture of myelopoiesis and caused massive expansion of myeloid progenitors leading to the formation of monoclonal GP clusters and oligoclonal MOP clusters whereas MDP are still found as single cells associated with dendritic cells. Even after this massive insult granulopoiesis and mono/DC poiesis remained spatially segregated to different sinusoids. Csf1 deletion in the vasculature prevented generation of MDP and dendritic cells in response to infection. In summary we have developed strategies to image and fate map myelopoiesis in situ; revealed spatial segregation of -and distinct clonal architectures for- granulopoiesis and mono/DCpoiesis; and identified rare CSF1+ sinusoids that maintain mono/DCpoiesis in the steady-state and after infection. These data indicate that there is a specific spatial organization of definitive hematopoiesis and that local cues produced by distinct blood vessels are responsible for this organization. Figure Disclosures No relevant conflicts of interest to declare.

Application of Simulation Methods for Study on Availability of One-Aisle Machine Order Picking Process

The main aim of the paper is the analysis of simulation model reflecting selected in-warehouse logistics processes in the aspect of their availability. For this purpose, one-aisle machine picking problem with use of a stochastic random simulation is studied, with a special focus on reliability of the system to disturbances and maintenance scheduling. The methodology in the research consists of classic measures of reliability. The model is designed in order to analyze availability of selected parameters of randomly generated order picking process. One of key-results of the paper is answer for question if a mean time to failure can be treated as a value of time when the first failure in the system occurs. A summary of the contribution includes discussion and the perspectives for further research in the subject matter.

Spatial Mapping of Myelopoiesis Reveals the Bone Marrow Niche for Monocyte Dendritic Cell Progenitors

Monocytes, macrophages and dendritic cells are indispensable for innate immunity. Myelopoiesis takes place in the bone marrow (BM) through differentiation of a common myeloid progenitor into monocyte dendritic cell progenitors (MDP) or granulocyte monocyte progenitors (GMP). MDP differentiate into myeloid progenitors (MoP) or common dendritic progenitors (cDP) that give rise to monocytes or dendritic cells (DC) repectively. GMP can also generate neutrophil-like monocytes via an intermediate monocyte progenitor [MP; Immunity. 2017 47(5):890] and neutrophils via a granulocyte progenitor (GP). CSF1 (M-CSF) is the key cytokine that regulates monopoiesis, CSF1 loss causes profound defects in monocyte, dendritic cell, macrophage and osteoclast generation. Classical studies using Csf1-/- chimeric mice demonstrated that CSF1 is produced by BM stromal cells. However the identity of these CSF1-producing cells is unknown. A major limitation is the lack of immunofluorescence protocols to map progenitor interaction with candidate niches. We have found that CD11b-Ly6C-CD117+CD115+ cells are MDP; Lin-Ly6C-CD117+CD16/32+CD115- cells are GMP; CD11b-Ly6C+CD117+CD115+ are MP/MoP; CD11b-Ly6C+CD117+CD115- are GP; CD11b+CD115+Ly6Chi and CD11b+CD115+Ly6Clo cells are classical and non-classical monocytes; and MHCIIhi reticular cells are DC. We used the markers above to map the 3D position of every myeloid cell in the sternum and assessed the relationships between myeloid progenitors, their offspring and candidate niches in situ with single cell resolution. To test whether the interactions observed were specific we obtained the X, Y and Z coordinates for every hematopoietic cell in the sternum (detected using αCD45 and αTer119). We then used these coordinates to randomly place each type of myeloid cell, at the same frequencies found in vivo, through the BM to generate a random distribution for each myeloid cell type. HSC localize to sinusoidal, arteriolar and endosteal niches. However, myeloid progenitors are exclusively perisinusoidal (mean MDP distance to sinusoids, arterioles, and endosteum observed 5, 134, and 105μm vs 9, 86, and 69µm in the random simulation). Myeloid progenitors rarely localize with HSC indicating that progenitors abandon the HSC niche upon differentiation. Strikingly, we found that granulopoiesis, monopoiesis and DCpoiesis occur in distinct sinusoidal locations and that MDP are tightly associated with sinusoids, dendritic cells and Ly6Clo monocytes (2.0 DC and 4.4 Ly6Clo monocytes observed within 50µm of an MDP vs 0.9 DC and 1.8 Ly6Clo monocytes in the random simulation p=0.02 and p<0.0001) but not with MoP/MP or Ly6Chi classical monocytes. The results above suggest that the stromal cells that provide the signals that regulate MDP will localize to the sinusoids. Analyses of Csf1 expression in two recently published scRNAseq studies of BM stroma showed that perivascular stromal cells and osteoblastic cells are the major CSF1 sources with sinusoidal endothelial cells expressing much lower levels. Csf1 deletion in perivascular cells using LepR-cre mice and in osteoblastic cells using Ocn-cre mice did not impact Ly6Chi classical or Ly6Clo non-classical monocytes in peripheral blood. We also did not find any defects in BM MDP, GMP, MoP numbers or colony forming activity or in monocyte or dendritic cell numbers. In sharp contrast we found that conditional Csf1 deletion in endothelial cells using Cdh5-cre mice led to a 3.9-fold defect in Ly6Clo non-classical monocytes in the blood (1.89 vs 0.47 x105/ml in the +/- controls vs Cdh5-cre:Csf1-/Δ mice; p=0.03). In the BM these mice showed a 1.4 reduction in MDP numbers (0.72 vs 0.5x104/femur; p=0.04) further compounded by a 2.7-fold loss in MDP-derived CFU-M (22 vs 8 colonies/100 cells; p=0.009) indicating a dramatic reduction in MDP function. This in turn led to a 2.3-fold reduction in Ly6Clo non classical monocytes (9.5 vs 4.1x104/femur; p=0.01) and a 1.2-fold reduction in cDC (2.7 vs 2.1 x104cDC/femur p=0.005). In summary we have imaged for the first time myeloid progenitors; mapped their differentiation into mature myeloid cells; quantified their interaction with candidate niche cells; showed that sinusoids are the exclusive site of monocyte and dendritic cell production; and demonstrated that endothelial cells are a niche that regulates MDP numbers and function via CSF1. Disclosures No relevant conflicts of interest to declare.