Analysis of a new multispecies tumor growth model coupling 3D phase-fields with a 1D vascular network

In this work, we present and analyze a mathematical model for tumor growth incorporating ECM erosion, interstitial flow, and the effect of vascular flow and nutrient transport. The model is of phase-field or diffused-interface type in which multiple phases of cell species and other constituents are separated by smooth evolving interfaces. The model involves a mesoscale version of Darcy's law to capture the flow mechanism in the tissue matrix. Modeling flow and transport processes in the vasculature supplying the healthy and cancerous tissue, one-dimensional (1D) equations are considered. Since the models governing the transport and flow processes are defined together with cell species models on a three-dimensional (3D) domain, we obtain a 3D-1D coupled model. We show some mathematical results on the existence of weak solutions. Furthermore, simulation results are presented illustrating the evolution of tumors and the effects of ECM erosion

Modeling and simulation of vascular tumors embedded in evolving capillary networks

In this work, we present a coupled 3D-1D model of solid tumor growth within a dynamically changing vascular network to facilitate realistic simulations of angiogenesis. Additionally, the model includes erosion of the extracellular matrix, interstitial flow, and coupled flow in blood vessels and tissue. We employ continuum mixture theory with stochastic Cahn--Hilliard type phase-field models of tumor growth. The interstitial flow is governed by a mesoscale version of Darcy's law. The flow in the blood vessels is controlled by Poiseuille flow, and Starling's law is applied to model the mass transfer in and out of blood vessels. The evolution of the network of blood vessels is orchestrated by the concentration of the tumor angiogenesis factors (TAFs); blood vessels grow towards the increasing TAFs concentrations. This process is not deterministic, allowing random growth of blood vessels and, therefore, due to the coupling of nutrients in tissue and vessels, makes the growth of tumors stochastic. We demonstrate the performance of the model by applying it to a variety of scenarios. Numerical experiments illustrate the flexibility of the model and its ability to generate satellite tumors. Simulations of the effects of angiogenesis on tumor growth are presented as well as sample-independent features of cancer.Comment: 36 pages, 22 figure

Winter-Hardy Vs. Freeze-Killed Cover Crop Mixtures Before Maize On An Organic Farm With Reduced Soil Cultivation

The advantages and disadvantages of a winter-hardy vs. a freeze-killed cover crop (CC) mixture were studied on an organic farm in Lower Austria in two consecutive experiments. Effects on soil inorganic nitrogen contents, weed density and the yield of a following maize crop were assessed. The winter-hardy compared to freeze-killed CC mixture, both consisting of legumes and non-legumes, reduced soil nitrate contents over winter, leading to a reduced nitrate leaching risk, whereas the yield of a following grain maize crop was not significantly affected. Weed density was high in both CC treatments, presumably due to a reduced, non-inverting soil cultivation before maize, and higher in the winter-hardy CC treatment at one of the assessment dates. Combined with an adapted soil cultivation, both winter-hardy and freeze-killed CC mixtures were suitable CCs before grain maize

Calibration to American options: numerical investigation of the de-Americanization method.

American options are the reference instruments for the model calibration of a large and important class of single stocks. For this task, a fast and accurate pricing algorithm is indispensable. The literature mainly discusses pricing methods for American options that are based on Monte Carlo, tree and partial differential equation methods. We present an alternative approach that has become popular under the name de-Americanization in the financial industry. The method is easy to implement and enjoys fast run-times (compared to a direct calibration to American options). Since it is based on ad hoc simplifications, however, theoretical results guaranteeing reliability are not available. To quantify the resulting methodological risk, we empirically test the performance of the de-Americanization method for calibration. We classify the scenarios in which de-Americanization performs very well. However, we also identify the cases where de-Americanization oversimplifies and can result in large errors

Business constraints and growth potential of micro and small manufacturing enterprises in Uganda

Ugandan micro and small enterprises (MSEs) still perform poorly. Studies associating poor performance of manufacturers with lack of finance and low investment ignore micro enterprises. Those focusing on MSEs are either exploratory in nature or employ a descriptive analysis, which cannot show the extent to which business constraints explain the performance of MSEs. Thus, this paper tries to examine the extent to which the growth of MSEs is associated with business constraints while controlling for owners’ attributes and firms’ characteristics. The results reveal that MSEs’ growth potential is negatively associated with limited access to productive resources (finance and business development services), high taxes and lack of market access

Ginger Stimulates Hematopoiesis via Bmp Pathway in Zebrafish

) has been widely used in traditional medicine; however, to date there is no scientific research documenting the potential of ginger to stimulate hematopoiesis. expression in the caudal hematopoietic tissue area. We further confirmed that Bmp/Smad pathway mediates this hematopoiesis promoting effect of ginger by using the Bmp-activated Bmp type I receptor kinase inhibitors dorsomorphin, LND193189 and DMH1.Our study provides a strong foundation to further evaluate the molecular mechanism of ginger and its bioactive components during hematopoiesis and to investigate their effects in adults. Our results will provide the basis for future research into the effect of ginger during mammalian hematopoiesis to develop novel erythropoiesis promoting agents

Dynamic Trajectories and Maturity of Farmer Collaboration for Biodiversity Sensitive Farming – Insights from the Framework Farmer Clusters

ContextBuilding on the Farmer Cluster (FC) approach, which has emerged over the past decade in England to address ecosystem degradation and biodiversity loss at the landscape scale, FRAMEwork, a Horizon 2020 project, established a network of eleven FCs across Europe.ObjectiveTo test the effectiveness of the FRAMEwork FCs, a new level of technological and scientific support was offered to the FCs providing a facilitated space for collaboration, co-production of knowledge, co-innovation, peer-to-peer learning, and monitoring.MethodsWe provide an overview of the eleven FCs and a comparative case study analysis to understand the dynamic trajectories and levels of maturity shaping the outcomes of the FCs. Expanding from the ‘success criteria’ of collaboration for sustainable agriculture by Velten et al. (2021), we identified five formative dimensions – governance, leadership, facilitation, group characteristics and context – influencing the outcomes of FCs, before analysing these dimensions in more detail.ResultsWe found that the five dimensions are interdependent and dynamic, affecting the functioning of the FCs, and leading to different levels of maturity. Comparing the situation of each FC regarding the five dimensions and the level of maturity we found that the FCs started in distinct contexts with diverse initial conditions across Europe – from favourable to unfavourable. This led to different dynamic trajectories on a pathway to biodiversity sensitive farming.SignificanceThe maturity assessment matrix offers a valuable tool for FCs to reflect on their progress and capacity in achieving their goals, guiding future efforts for effective FC management