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Plant Breeding Simulation

Austin Gratton
for more information, contact Dr. Ann Stapleton at:
A simple model for breeding plants from generation to generation, with one "yield" variable (e.g. height) and 4 combinations of plants from the parents. Simulation tracks the frequencies of each combination in each generation as well as the overall average height by generation.
Adjust all sliders before beginning simulation. Make sure the A1A2 parameters are equal to the A2A1 parameters.

Environment Breeding Biology Plants

  • 2 years 5 months ago

Bipolar II dynamics

Eduardo Enrique Escamilla
Bipolar II treatment modeling using Van der Pol-like oscillators.

In this simulation an afflicted individual with Bipolar II disorder is put to treatment after 20 months the calibration of the medicine or treatment he recieves is such that it simulates the natural cycles of a "normal being". You can note by manipulating the parameters that sometimes too much treatment disrupts equilibria. Also note that in the state diagrams there are 2 limit cycles, the lower one being the healthiest as there are less changes.

Physics System Zoo Science Psychology Biology

  • 7 years 10 months ago

Evolution extended synthesis

Geoff McDonnell

​From Fig 1.1 p11  Pigliucci M and Muller GB (2010) Evolution: The Extended Synthesis. This is a shift in emphasis from statistical correlation to mechanistic causation (p12), including the conditions for the origin and innovation of traits (p13). It overcomes the gradualism, externalism and gene centrism of the Modern Synthesis. Non-gradual change is a property of complex dynamical systems. EvoDevo processes generate particular forms of change rather than others.Genes are followers in the evolutionary process that capture the emergent interactions among environment, development and inheritance into genetic-epigenetic circuits, which are passed to and elaborated on in subsequent generations (p14).

Biology Evolution

  • 3 years 5 months ago

Is Osteoporosis More Avoidable than we Thought?



JUNE 2013

There are many factors that lead to an increased risk of osteoporosis later in life. Some of these risks are congenital; fixed risks that were acquired during fetal development. Other risks are created or reduced by an individual depending on their lifestyle; which make them unfixed variables. 

Definition: OSTEOPOROSIS (Also known as degenerative bone disease) - "is a disease of bones that leads to an increased risk of fracture. In osteoporosis, the bone mineral density (BMD) of an individual is reduced, bone micro-architecture deteriorates, and the amount and variety of proteins in bone and variety of proteins in bone are altered. Osteoporosis is defined by the World Health Organization as a bone mineral density of 2.5 standard deviations or more below the mean peak bone mass (average of young healthy adults)."


Age: Increased age increases likelihood of developing osteoporosis

Sex: Females are more likely to experience osteoporosis fragility fractures

Race: Osteoporosis is more common in people of European and Asian decent

Frame: Thin-framed individuals do not stress their bones as much as heavier-set individuals, and therefore do not have as "thick" bones, and are more likely to develop fragile bones (osteoporosis) 

Family history: 30 genes are linked to development of osteoporosis, so an individual can be anywhere between 25 and 80% more likely to develop osteoporosis if it exists in the family. (my mother has it, so I am very likely to develop it if I don't actively make the efforts to protect my bones from degenerating over time.)

Insufficient Prenatal Care: During development in the womb if a fetus does not receive appropriate nutrition, it may develop malnutrition-related deficiency diseases.


Smoking/Drinking: Excessive use could lead to increased risk because alcohol use decreases your ability to absorb nutrients. It interferes with the absorption of calcium and Vit D (stomach, pancreas and liver affected). Alcohol also kills osteoblasts, the bone-making cells. It also increases bone-damaging hormones cortisol and parathyroid hormone 

Medication Use: Some medications increase risk of osteoporosis however discontinuing use of said medications is often impossible, and therefore the modifiable risk is non-modifiable at times.

Dietary Habits: Majority of bone development happens before an individual reaches the age of 20, so if dietary requirements of calcium, vitamin D, and phosphorus are insufficient, there will be a greater chance of osteoporosis later in life. 

Hormone Levels: In females, estrogen deficiency following menopause or oophorectomy is correlated with rapid reduction in bone mineral density, while in men, a decrease in testosterone levels has a comparable (but less pronounced) effect.

Sedentary Lifestyle: Staying active and stressing your bones decreases chances of osteoporosis because it encourages osteoblastic activity, if an individual is extremely sedentary, (coupled with a thin frame possibly) they are very susceptible to osteoporosis, and should consider getting active. Also, an individual with more sun exposure absorbs more Vit D.

Fractures: Increased breakage of bones creates weak points where BMD cannot recover to what it was prior to the fracture. Individuals should stay out of fights, reduce falling, and avoid clumsy behavior.


  • 7 years 7 months ago