a. State Variables and State Space:
1.Cell Density (N): The number of yeast or bacterial cells present in the chemostat at a given time. The state space for N is the set of non-negative real numbers (N ≥ 0).
2.Concentration of Substrate (S): The concentration of the nutrient (e.g., glucose) in the liquid medium. The state space for S is the set of non-negative real numbers (S ≥ 0).
3.Dilution Rate (D): The rate at which medium is added to the chemostat relative to the volume of the chemostat. The state space for D is the set of non-negative real numbers (D ≥ 0).
4.Effluent Concentration (S_out, N_out): The concentration of substrate and cell density in the effluent leaving the chemostat. The state space for S_out and N_out is the set of non-negative real numbers (S_out ≥ 0, N_out ≥ 0).
b. Parameters:
1.Maximum Specific Growth Rate (μ_max): The maximum growth rate of cells under ideal conditions (maximal nutrient availability and absence of inhibitory factors). It is a positive real number (μ_max > 0).
2.Half-Saturation Constant (K_s): The concentration of substrate at which the specific growth rate is half of μ_max. It is a positive real number (K_s > 0).
3.Yield Coefficient (Y): The amount of biomass (cells) produced per unit of substrate consumed. It is a positive real number (Y > 0).
4.Dilution Rate (D): This is both a state variable and a parameter. As a parameter, it represents the rate at which medium is added to the chemostat, and it can vary within the state space (D ≥ 0).
5.Inlet Concentration (S_in): The concentration of substrate in the incoming medium. It is a positive real number (S_in > 0).
6.Effluent Flow Rate (Q): The rate at which medium and cells exit the chemostat through the effluent tube. It is a positive real number (Q > 0).
7.Cell Death Rate (μ_death): The rate at which cells die in the chemostat due to factors such as predation or aging. It is a positive real number (μ_death > 0).
c. Justification for Model Type:
This should be a continuous time model because the growth and dynamics of yeast and bacterial populations in a chemostat occur continuously over time. Cells divide continuously, and changes in cell density, substrate concentration, and other state variables are continuous and smooth. Discrete time models, which operate in discrete time steps, may not capture the nuances of these continuous processes accurately. Therefore, a continuous time model, possibly using differential equations, would better represent the system's behavior in a chemostat.
Answer:
D
Explanation:
Why is it important to know a person's rhesus factor before a blood transfusion?
A patient who is Rh+ can receive only Rh– blood.
A patient who is Rh– can receive only Rh+ blood.
A patient who is Rh+ can receive only Rh+ blood.
A patient who is Rh– can receive only Rh– blood.
B.Tropical rain forest and Taiga
C.Savanna and grassland
D.Grassland and desert
b. herbicides
c. net barriers
d. inspecti
Answer:
C) net barriers
Explanation:
Both A and B are forms of chemical control and D, inspections, is a tool used to determine what type of control is needed. A is one form of mechanical control.
A: When an invasive species first becomes introduced into a new area, there may be a chance to eradicate it through a rapid response action if it is detected in time. If eradication is not possible, then the species may be subject to control and management efforts. Regardless of whether the goal is eradication or control/management, there are a suite of different options, which differ depending on the species, which one must consider. When making decisions on which options to use, one must use an Integrated Pest Management approach to choose the options which will be the most environmentally sound yet still affect the invasive species as strongly as possible. The various options for eradication/control/management include:
Physical or Mechanical Control - This type of control involves physically removing the invasive species (i.e. harvesting) or using barriers or traps to prevent their spread or to capture them. For invasive plants, mowing is another example of physical control.
Chemical Control - This type of control involves all sorts of pesticides (herbicides, insecticides, fungicides, piscicides, etc.) Although chemical use can be very effective, they can be very dangerous to other species or to the ecosystem in general and must be used in an environmentally sound manner. The key is to choose chemicals that are low-risk yet effective and that can be applied when the pest is at its most vulnerable.
Cultural Management - Cultural management is the manipulation of the habitat in ways that increase the mortality of the invasive species or reduce its rates of increase and damage. Cultural management that can affect invasive species including: selection of pest resistant varieties of crops, mulching, winter cover crops, changing planting dates to minimize insect impact, burning, flooding, crop rotations that include non-susceptible crops, moisture management, addition of beneficial insect habitat, or other habitat alterations that help the native species compete better against the invasive ones.
Biological Controls - This type of control is the purposeful use of an invasive species’ enemies (predators, parasites, and pathogens) – in other words other exotic species – to reduce the invasive species populations. This option involves much research and testing to be sure the species to be used preys only on the target invasive species.
US Fish and Wildlife F&Q
they keep all of the viruses out. it is a defencive system
The right answer is A.
Since matter is generally composed of several pure bodies (chemical compounds and simple bodies), the chemical composition of a product furnishes the quantity or proportion of each of the pure substances which compose it; they are generically called components.
For answer B it is rather the definition of a chemical structure, it refers to both its molecular topology, its geometry (molecular geometry or space group for a crystal) and its electronic structure.
b. Aces the plastic bag was permeable to iodine.
c. The iodine moved into the plastic bag.
d. The cornstarch moved into the beaker.
e. The plastic bag was selectively permeable.
The solution in the dialysis tubing bag turning dark purple indicates that the iodine has moved into the bag and reacted with the cornstarch. This means that options (b) and (c) are correct.
The dialysis tubing bag is selectively permeable, which means that it allows certain molecules to pass through while blocking others. In this case, the bag is permeable to iodine molecules, but not to larger molecules such as cornstarch. Therefore, option (e) is also correct. The cornstarch did not move into the beaker, as the bag is designed to keep its contents inside. Therefore, option (d) is incorrect. The fact that the solution in the bag turned purple indicates that the bag was permeable to cornstarch, as it allowed the iodine to come into contact with the cornstarch and produce the purple color. Therefore, option (a) is also correct.
Because the solution in the bag turned purple as a result of the iodine's contact with the cornflour, it can be concluded that the bag was permeable to cornflour. This contact enabled the purple colour to be produced. As a result, choice (a) is also accurate.
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