Apterous is an allele that results in a fly without wings. Wild-type variants have normally functioning wings. The goal of this simulation is to determine the pattern of inheritance for the apterous phenotype. Is apterous dominant or recessive? Sex-linked or autosomal? Complete, incomplete, or codominant?
White-eyed is an allele that results in a fly white eyes. Wild-type variants have red eyes. The goal of this simulation is to determine the pattern of inheritance for the white-eyed phenotype. Is yellow body dominant or recessive? Sex-linked or autosomal? Complete, incomplete, or codominant?
A very simple, one stock, simulation of campus sexist attitudes toward rape and initimate partner violence. The model was originally developed in 1998 and later translated into Stella. The model has a number of modeling errors, but at the time, proved useful for gaining insight into the dynamics of the system and developing an innovative prevention program.
Este modelo es un primer intento de utilizar el "Business Canvas" desarrollado por Alexander Osterwalder e Yves Pigneur, para explicar su carácter sistémico mediante la simulación de un modelo de negocio genérico utilizando Stella Architect. El objetivo principal es mostrar el vínculo entre los conceptos del pensamiento sistémico y la práctica del "Systems Dynamics" con el ampliamente difundido "Business Canvas". En la narrativa utilizada para describir la construcción del diagrama "Stock & Flow", se denomina entre parentesis el tipo de componente (Stock, Flow, Converter, o Conector) correspondiente a los principales elementos del modelo de negocio. La simulación permite visualizar la naturaleza sistémica de un modelo de negocio representado mediante el "Business Canvas".
Congratulations! You've just been hired by the major grocery chain The Price Shopper as head of marketing. Your job is to turn around The Price Shopper's dismal sales of laundry detergent. The big-wigs have given you 12 months and a marketing budget of up to $10,000 per month to spend as you please. They'll decide to keep you, or send you to the cleaners based on how much profit you bring in over the year. Do you think you can make the big MONEY?
This is our first model in the From Imagination to Simulation series. It is a nod to the Halloween season and investigates a zombie apocalypse! Our fascination with zombies continually grows with the help of movies, TV shows, and books that give a wide range of zombie possibilities. But what are the dynamics behind a zombie epidemic? This model will specifically look at the spread of a zombie outbreak and examine some of the variables that help and hinder the rate of infection. We hope you will continue to see the benefits and versatility of Systems Thinking and enjoy our new series, From Imagination to Simulation! Continue to ponder those out-of-the-ordinary problems. They may seem unrealistic, but perhaps some of their dynamics may resonate with reality. Check out our zombie apocalypse model to see if there is any chance for human survival!
Simulation allows students to test the transformation principle. Two major goals of the experiment are: 1. Allow users to see that supernatant from heat-killed bacteria can transform the genes of another bacterium. 2. What transforms the inheritance of the bacteria is DNA, not RNA or proteins.
A country builds its empire by attacking its neighbours and taking over both their land and their people. The larger the empire becomes, the more resources they have available to take further territory by force. However the further they expand, the harder they find it to keep expanding due to the geographical and organisational logistics involved. Additionally the empire finds it harder to maintain social cooperation among its people, its asabiya.
Do you ever feel like work is taking over your life? Burnout is generally characterized as a state of mental and physical exhaustion resulting in low productivity and de-personalization and is most likely caused by prolonged stress that does not dissipate. There are many different aspects that affect both the building and dissipation of burnout. This model focuses on workloads and vacations to see how they contribute to both your level of burnout and productivity. Use this model to ask questions about your workload and any benefits you would receive from taking a vacation. What happens when you suddenly have a bigger workload? What happens when work piles up? Does vacation increase or decrease your stress levels?
This simulation gives the user the ability to specify their own current condition (weight, age, height etc.), choose their exercise regime and eating plans. The simulator then gives a projection for the user's weight for the next year (at a weekly resolution). Please take note that most of the pictures are navigation buttons to different screens, so remember to click on the pictures. I have personally used this simulator to successfully lose more than 20 kg. Hope you find this as valuable as I did. Good luck with your weight journey!
Karner Blue butterfly is an endangered species. Habitat loss and climate change are contributing factors to the reduction in the butterflies' population sizes. Climate change can alter the timing of lifecycles. When climate change disproportionally affects the timing of life cycles of species in an ecosystem asynchrony within a food web occurs.
The Bass Model or Bass Diffusion Model was developed by Frank Bass and it consists of a simple differential equation that describes the process of how new products get adopted in a population. The model presents a rationale of how current adopters and potential adopters of a new product interact.
Each year, the cost of a college education continues to rise and more and more students must turn to student loans to complete their education. But as graduates leave college to embark on their careers, they face an almost Sisyphean struggle with student debt, forever facing an uphill battle while carrying a heavy burden, only to find they are getting nowhere! Whether you are graduating from college or just entering, we hope this model will enable you to better understand student loans and help plan for your future.
Here we depict a melding of two systems of thought: the water-energy-land-food-climate (WELFC) nexus with the Anthroposphere. It analyzes the complex interactions among the WELFC sectors within the global context of the human sphere, containing the political, economic, social, environmental, etc. to form a holistic framework to understand how all these sector function together.
This simulation shows the basic dynamics of a hospital emergency room. Patients arrive, are treated and leave. You are able to control the average arrivial rate and average treatment time. This simulation was made using the 3rd party developer API embedded within Stella Architect.
In this game you play the part of Dunkin Donuts in an established market of 1,000,000 coffee drinkers. This market is controlled only by Dunkin Donuts and Starbucks, there is no other competition. The market is segmented into 4 sub-groups: Heavy Regular, Heavy Espresso Base, Occasional Regular Occasional Espresso Base. The occasional coffee drinkers normally order a pastry (donut, cake, etc.) with their coffee more often than the the heavy coffee drinkers, but on an individual by individual basis the heavy coffee drinkers are buying more donuts each month than the occasional coffee drinkers. For this game you are concerned with selling 3 products: Regular Coffee, Espresso Base Coffee, Pastry (donuts, cakes, etc.) For each product you sell you have control over the following decisions: Process Improvement Spending, Taste Improvement Spending, Marketing, Price. Finally you can then also choose to open new stores or close existing stores.
This is the second version of the simulation that analyzes the interactions among the six Sustainable Development Goals (SDGs) that are the focus of the Second Annual Multi-stakeholder Forum on Science, Technology, and Innovation for the Sustainable Development Goals (STI Forum). The interface can be used to understand the trade-off due to the complex interplay among the set of six SDGs
The purpose of this model is to (1) demonstrate a way to represent human development that includes individual resources, social networks, and spatial relationships within a single model of a formal feedback theory of development, (2) provide an approach to theory development that begins with a simple model and gradually includes more complex facets of social reality (e.g., social networks, location), and (3) illustrate its application to formally testing and comparing a theory over a wider range of assumptions that can inform the design of data collection and analysis to more accurately reflect the dynamics of human development and outcomes. The approach has a wide range of possible applications in theory development and community intervention design, research, and evaluation. Examples include school-based and community based positive youth development interventions, drug use/addiction and treatment in rural settings, community responses to domestic violence, neighborhood effects and interventions, homelessness, supports for ex-offenders released from prison or jail, and health inequities. Version 1.0 focuses on mainly working out a simple example of interactions between social networks and spatial relationships. The model (right) represents a formal theory of how people will move to be close to their nearest friend. Since friends are determined by a social network where people have different sets of friends, and people are in different locations, movement will depend on an interaction between each individual’s social network, the location of their friends, the distance to their friends, and identifying their nearest friend and comparing one’s present location to the location of one’s nearest friend. The model implements this with a random social network for 100 individuals randomly distributed in 100m by 100m coordinate space.
Explore a consulting firm’s headcount strategy. Understand the relationship between growth rates, promotion times, headcount pyramid ratios, and attrition rates. This model is based on actual work that was done with a very well-known consulting company (here, code-named TWBC, Inc.). The firm's strategic goals were well-articulated, and each made sense when written down in a list on a piece of paper. However, when subjected to the more rigorous, dynamic scrutiny that an iThink modeling effort provides, the goals (as is too often the case) turned out to be in conflict with one another--stimulating actions that worked at cross-purposes. Efforts to achieve one goal drove the firm farther away from achieving the others. The subsequent analysis conducted with the model also pointed the way toward resolving the internal strategic inconsistencies and putting the firm back onto a strategically sound growth path.
Tryptophan is an amino acid that is synthesized by plants and bacteria from other molecules in a biochemical pathway (see diagram below). The trypophan operon is a series of sequential genes found on a bacterial genome. The genes of the operon produce the enzymes that direct the synthesis of tryptophan. In this model you will experiment with the negative feedback loop of the repressible system.
The dynamic model shall explain the rapid diffusion of the lionfish - an invasive species - throughout the Caribbean Sea and the Atlantic Ocean. The interface contains two explanatory models - a simple diffusion model and more realistic convection model - as well as a policy game to manage the regional countermeasures of local decision makers.
Dairy farmers in Matiguás, Nicaragua face feed system constraints that reduce their competitiveness. Conventional value chain analysis methods are unsuited to prioritize upgrading options. System dynamics modeling of the Matiguás dairy value chain was therefore used to quantify and analyse policy impacts. The model was constructed and tested with stakeholders in the Matiguás dairy value chain through group model building.
The main dependent variable measured in the model is the membrane potential (millivolts) of a motor neuron and the muscle fiber it innervates. You will be able to add excitatory and inhibitory neurotransmitters, and compare how neurotransmitters modulate the electrical impulses of the motor neuron and the muscle fiber. Additionally, you will be able to compare the effects of four neurotoxins: Tetrodotoxin, botulinum toxin, sarin nerve gas, and VX. While extremely lethal, these toxins are very instructive in understanding neurons because of the specific way the toxins act. Each toxin modifies or inhibits a specific molecule in neurons that help process and transmit information.
Keystone species are defined as a plant or animal that plays a unique role in the way the ecosystem functions. But what would happen if that species were removed? What ripple effects would be caused by the absence of this species? We can examine these questions by looking at the wolf population in Yellowstone National Park. Wolves once flourished in Yellowstone and its surrounding areas. However, soon after the area was settled, misperceptions caused by fear and hatred fueled a large extermination effort of the wolves. For nearly 70 years, wolves were absent from Yellowstone. During this time, the ecosystem changed and diminished until scientists realized the value of the wolves and reintroduced them to Yellowstone. This model, built in iThink, uses storytelling to understand the dynamics of this keystone species. What animals were affected by their presence or absence. See how wolves play a part in not only population control of their prey but other animals and even plants far down the trophic levels.
Many drugs are removed from the body by metabolism in the liver. A drug's hepatic clearance is a measure of the liver's ability to metabolize a drug. This simulation demonstrates the characteristics of high extraction (nonrestrictive clearance, low extraction (restrictive clearance and intermediate clearance.
This simulation is based on the SCREI model, simulating early recruitment of the Barents Sea cod stock under ocean warming and acidification. The model is based on experimentally quantified data and calibrated to empirical cod egg production, 0-group abundance and ecological data. It allows the exploration of different climate change driver trajectories and adaptaion scenarios.
A look at disaster relief under uncertain local government scenarios. It looks at how long it might take to establish clean water thru flying in bottled water and constructing wells. There is also the impact on spread of disease and survival due to lack of water. Created by Mark Heffernan and George McDonnel
This simulation shows the location and functioning of the major clinically important drug transporters in the : gastrointestinal membrane; renal tubular membrane; and the membranes of the hepatocyte. Simulations demonstrate their functioning after oral and intravenous doses of a drug substrate
The main dependent variable measured in the model is the membrane potential (millivolts) of two different neurons in a series. You will be able to add excitatory and inhibitory neurotransmitters, and compare how these modulate electrical impulses of the two neurons. Additionally, you will be able to compare the effects of three neurotoxins: Tetrodotoxin, botulinum toxin, and sarin nerve gas. While extremely lethal, these toxins are very instructive in understanding neurons because of the specific way the toxins act. Each toxin modifies or inhibits a specific molecule in neurons that help process and transmit information.
Nonlinear or capacity limited pharmacokinetics can occur whenever a process involved in the absorption, distribution or elimination of a drug becomes saturated. This model demonstrates nonlinear elimination (metabolism) using phenytoin as the model drug. Specifically, it demonstrates how increasing doses of the drug produce disproportionate increases in the plasma concentration. It also demonstrates how the model parameters, Km and Vmax influence of the plasma concentration -time profile.
With this model I model the physical locations of all individuals in real space. (X,Y location). Individuals move randomly each day so that they mix. Based on an individuals location relative to each other individuals there is a chance for a person to communicate the infection to another person. To determine if the infection is communicated we draw a random number. If the number is equal to or less then the chance of infection if the other person is the carrier then the person P contracts the infection and can then spread it through the population. What is superior about this model is that we can now EASILY model the attributes of any individuals as a stock arrayed by Individuals and the interaction of people with others as arrayed variables by Individual, Individual. For instance if we wanted to model the time that an individual has had a disease we can do that by creating a stock called time_infected and have an inflow of 1 for each day that an individual is in the infected state.
Some drugs act by binding covalently to their receptors. As a result, the target is destroyed and its function returns only when it has been replaced by newly synthesized product. The target may be a protein, DNA, an enzyme, or a cell at any stage of development. This model has been applied to the action of the proton pump inhibitors, which bind to and destroy the H+,K+-ATPase pumps in the parietal cells of the gastric mucosa. Normal proton secretion is restored only when the pumps are replaced by newly synthesized functioning pumps (i.e., the usual turnover time of the system).
Second iteration of price war multiplayer game for ISDC 2017. Two players are required a third is optional. Each player is competing to control the market. They sell perfect substitutes with equal production costs. Your only choice is what price you sell your product at
This model represents dynamics of crop selection decisions by two groups of farmers: upstream and downstream. These groups of farmers select crops based on several factors including market signals, crop characteristics, and quantity and quality of available irrigation water.
Some drugs do not directly produce the measured drug response. Instead they act upstream, and either increase or decrease the amount of the entity that directly mediates the response (response variable). Indirect effect Model IV can be used for drugs that stimulate the degradation of the response variable. As a result they decrease the amount of the response variable.
Some drugs do not directly produce the measured drug response. Instead they act upstream, and either increase or decrease the amount of the entity that directly mediates the response (response variable). Indirect effect Model III can be used for drugs that stimulate the production of the response variable. As a result they increase the amount of the response variable.
Most commonly people take oral doses of a drug over an extended period. This model demonstrates the unique plasma concentration profile associated with this type of drug administration. The model assumes first-order drug absorption with no lag time. Simulations can be carried out to observe how the rate and extent of absorption (bioavailability) affect the profile.
The model shows the unique plasma concentration-time profile associated with the administration of a drug using multiple short infusions. It demonstrates the influence of the duration of the infusion and allows the user to practice the calculation of a suitable dose and dosing interval to achieve desired peak and trough plasma concentrations of a drug.
This is a simple, working example of system dynamics model which was used as a supporting material in my seminar in "What is System Dynamics?" on Feb 24th at Water Resources Research Institute, New Mexico State University.
This model shows the typical plasma concentration profile associated with the administration of several doses of a drug over time. It demonstrates the determinants of the fluctuation in the plasma concentrations, the accumulation of the drug over the course of therapy and the resting steady state plasma concentrations.
Putting trust in your model is a simple demonstration of the importance of the human dimension to system change. By thinking about trust as something that impacts on human behaviours this model shows how investment in such factors can be better for the patient and for finances.
This model shows the typical effect of several anticancer drugs on the number of circulating neutrophils. The drugs destroy neutrophils as they develop in the bone marrow, and its takes several days for their action to affect the circulating neutrophils. The model demonstrates how inter-individual variability in pharmacokinetics and pharmacodynamics can effect the magnitude and duration of this response.
Change image Submit your own comment on the simulation. Share Comment upgrade hosting plan delete simulation Transit Compartment Model of Drug Response By Sara Rosenbaum Sim URL: https://forio.com/simulate/sarar/transit-compartment-model Sim access:Other authors can download source model Sim plan: Simulate Free Sim stats:This sim has been run 326 times. This simulation was uploaded to Forio Simulate with the isee NetSim software. More information can be found at iseesystems.com. Your Rating: 1 star2 star3 star4 star5 star Average Rating: rating(1) Click here to edit the description A delay in response to a drug can occur when it takes a long time for the drug’s initial effect to be translated into the final response (a long transduction process). The delayed response profile can be captured using a series of transit compartments.
This is the first interface I built. It is the result of a one week seminar on Stella Architect taught by Billy Schoenberg in Bergen in 2016. We spent 2 days on an introduction into Stella Architect.
Tolerance may be defined as a process that results in a reduction in the response to a specific drug concentration following repeated drug exposure. Tolerance could occur if an endogenous compound that plays an essential role in the response chain becomes depleted during response. This model assumes the drug stimulates the production of a response variable which becomes then becomes depleted.
This is the model that is most commonly used to for the time course of drug effects in man. It assumes that the response is driven by the blood or plasma concentrations of the drug. When the model parameters are known, it can be used to predict response at anytime time after any dose.
Use this model to see if you can use a drug's pharmacokinetic and pharmacodynamic properties to determine the initial rate of drug administration. See if you can identify potential drug-drug interactions and respond when appropriate by making appropriate modifications to the dose.
Some drugs do not directly produce the measured drug response. Instead they act upstream, and either increase or decrease the amount of the entity that directly mediates the response (response variable). Indirect effect Model I can be used for drugs that inhibit the synthesis of the response variable. An example is warfarin which inhibits the synthesis of clotting factors.
This simulation demonstrates the properties of time dependent enzyme inhibition. Specifically it shows how the inhibitor’s KI and kinact and the derived parameter kobs, control inhibition. It also demonstrates how the enzyme’s degradation rate constant controls recovery.
Some drugs do not directly produce the measured drug response. Instead they act upstream, and either increase or decrease the amount of the entity that directly mediates the response (response variable). Indirect effect Model 2 can be used for drugs that inhibit the degradation of the response variable. As a result they increase the amount of the response variable.
This simulation shows the basic dynamics of a hospital emergency room. Patients arrive, are treated and leave. You are able to control the average arrivial rate and average treatment time. This simulation was made using the Animation Object within Stella Architect.
Lipoamide is a fictitious antipyretic (fever reducing) drug that is believed to work by reducing the synthesis of cytokines. Based on its mechanism of action and the characteristics of its response, an indirect effect model I (inhibition of kin) was used to model its effect. This model can be used to probe optimum dosing regimens of lipoamide.
This model assumes permeability controlled hepatic uptake and demonstrates the role of passive diffusion, hepatic uptake transporters, hepatic matabolism and hepatic efflux transporters on overall hepatic elimination
This Story of the Month reissue examines the complexities of school reform. Inspired by a major school reform effort in Philadelphia, this story explores some of the potential unintended consequences. What happens when the focus of "fixing schools" becomes increasing scores on standardized tests? The Story of the Month series was originally issued starting in May of 2001. While many things have changed since then, many of the issues remain relevant. From corporate corruption, to terrorism, to greenhouse gasses, each story analyzed a past headline news topic from a systems thinking perspective. These topics were modeled using STELLA or iThink with the hopes to gain perspective on the system, stimulate discussion and perhaps adjust our assumptions. isee systems has been re-releasing each Story of the Month from our archives, as originally developed, with an easy-to-access isee Sim Exchange.
This simulation demonstrates the model used for the induction of the drug metabolizing enzymes. It illustrates how the inducing drug's characteristics (Emax and EC50) control the degree of induction and the rate of degradation of the enzyme controls recove..
Model Mysteries Chapter 2: Energy Drink Mania Model 1: Basic Model
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