CATDOLL : CATDOLL: What are the factors that affect the survival rate of tadpoles during transportation?

1. What are the factors that affect the survival rate of tadpoles during transportation?

The main factors that affect the survival rate of tadpoles are as follows: (1) Water temperature. Bullfrog embryos cannot tolerate low temperatures, but tadpoles can tolerate low temperatures and can survive even when the water temperature drops below 5 degrees, but they cannot adapt to high temperatures. The test results show that when the water temperature reaches 35 degrees, the tadpoles' activity decreases and their food intake decreases. At 37 degrees, there is mild mortality, at 39 degrees, there is severe mortality, and above 40 degrees, all tadpoles will die.

Therefore, during high temperatures, artificial cooling measures must be taken, such as setting up a shade shed above the pond, planting duckweed or water hyacinth in the pond, and frequently filling the pond with new water to regulate water quality and water temperature, which plays a good role in improving the survival rate of tadpoles. (2) Stocking density.

The stocking density of tadpoles of different sizes is different, especially the stocking density of early tadpoles (3-1.4 cm) has a significant impact on the survival rate. When the stocking density of early tadpoles exceeds 1000/m2, the survival rate is significantly reduced. When it reaches 2000 per square meter, the survival rate is only 18%.

(3) Water quality. There are many factors that affect the deterioration of water quality, the main one being the reduction of dissolved oxygen in the water, such as oxygen consumption by organic matter, pollution, and the respiration of biological organisms, including tadpoles, which consume oxygen and produce carbon dioxide. This is the direct cause of the deterioration of water quality. On June 12, 1983, we put 100 tadpoles, 10 days after decapping, into a glass tank filled with 1000 ml of water. Five days later, all of them died. Water quality analysis showed that the dissolved oxygen content was only 3.

8 mg/L (25 degrees). (4) Human disturbance. The survival rate of tadpoles in the original pond after hatching is significantly different from that in the pond transferred after human disturbance.

2. What is transportation structure? What are the factors that influence transportation structure?

The transport structure includes:

1. The volume structure refers to the composition of the quantity of various industrial and agricultural products in the freight volume completed by various modes of transport, as well as the proportion of passengers of various natures in the total passenger volume.

2. Regional structure refers to the regional distribution of the length of operating routes of various modes of transport, the number of transport vehicles and the number of passengers and freight.

3. Technical structure refers to the technical means adopted by various modes of transportation and the technological level they possess.

4. Investment structure refers to the investment proportion relationship between various modes of transportation.

5. Capacity structure reflects the proportional relationship between the transport capacities of various modes of transport and can usually be expressed in terms of total tonnage of transport.

3. What are the factors that affect the transport of organic matter?

Temperature affects the speed and direction of organic matter transport in plants. The specific effects are as follows:

1. Temperature affects the transport speed of organic matter. When the temperature decreases, respiration weakens accordingly, and the transport speed of organic matter decreases accordingly; when the temperature increases, respiration increases accordingly, and the transport speed of organic matter increases accordingly. However, if the temperature is too high, respiration increases, which will also consume a certain amount of organic matter. At the same time, the enzymes in the protoplasm may also begin to be passivated or destroyed, so the transport speed of organic matter decreases.

2. Temperature affects the transport direction of organic matter. When the soil temperature is higher than the air temperature, it is conducive to the transport of photosynthetic products to the top of the plant; when the air temperature is higher than the soil temperature, it is conducive to the transport of photosynthetic products to the roots of the plant.

4. Briefly describe the water ecological factors that affect the overwintering survival of fish?

1. Poor physical condition of fish during the winter: Generally speaking, large-sized fish have good physical condition and high survival rate during the winter. Small-sized fish have poor physical condition and less nutrients such as fat accumulated in their bodies. It is difficult for them to maintain energy for survival during the long wintering period and they often die due to physical weakness. However, if the feed formula is unreasonable, the vitamin content is unbalanced or the amount of growth promoter added exceeds the standard, although it does not affect the growth of the species, it will seriously affect the physical condition of the fish and make the fish "fat". The immunity of such fish decreases and it is difficult to survive the winter. Especially in the late winter, they are susceptible to infection by pathogens, fish diseases break out, and wintering losses occur.

2. Hypoxia and low temperature in subglacial water:

(1) Snow is not cleared in time or the clearing area is too small, resulting in poor light transmittance, which affects the photosynthesis and oxygen production of phytoplankton.

(2) The water is thin and lacks fertilizer, the amount of phytoplankton is small, and the oxygen production is insufficient; the zooplankton reproduces in large numbers, and the oxygen carrying capacity increases.

(3) The bottom mud of old ponds is too thick and the high organic matter content causes hypoxia.

(4) Improper water injection or oxygenation. Blindly flushing water or adding oxygen for a long time will cause the water temperature in the pond to drop rapidly, and the turtles will be frozen to death.

3. Harmful substances exist in the wintering pool: Due to the increase in wintering density, harmful gases cannot escape after ice closure, and accumulate more and more in the water. Once the standard is exceeded for a long time, it will cause harm to the wintering fish. The most easily produced chemicals are ammonia nitrogen, nitrite, hydrogen sulfide and carbon dioxide.

4. Fish overwinter with diseases: Pathogens infected during the summer and autumn breeding stage are not treated in time, and the disease accumulates in the winter. The five species have poor physical fitness and poor ability to resist diseases and adverse environments, which increases the chance of infection with fish diseases and leads to fish disease outbreaks.

5. What are the factors that influence transportation policies?

Factors influencing transportation policies include national economy, market prices and transportation capacity.

6. What are the factors that affect railway transportation production safety?

There are many factors that affect the safety of railway transportation: natural disasters and man-made disasters are the main factors.

7. What are the factors that affect the survival rate of young rabbits?

Hello, my name is Qing Gege. More and more people are raising rabbits, so let me answer this question!

Survival rate is an issue that the breeding industry must pay attention to, because it is related to the direct economic benefits of breeding. Since the bodies of young rabbits have not yet matured, their resistance is weaker than that of adults. Rabbits at this stage are also more susceptible to diseases. So how to improve the survival rate from a technical level?

The factors that affect the survival rate of young rabbits are mainly as follows:

1. When young rabbits are weaned, they are in poor physical condition, malnourished, and have weak disease resistance. If other supporting measures are not taken, they are easily infected with diseases and die.

2. Irrational diets. A few farmers pursue rapid growth of young rabbits and blindly prepare high-energy, high-protein diets, which have the opposite effect, causing a large number of young rabbits to die from diseases such as Clostridium perfringens. Some farmers still use traditional feeding methods after introducing improved breeds, feeding only grass, or simply preparing diets that do not meet nutritional requirements, resulting in malnutrition and weakness of young rabbits.

3. Improper feeding. Many farmers have a strict feeding system, but do not feed rabbits at regular times and in irregular quantities, which causes the rabbits to be hungry or full at irregular times, overeat, and cause digestive diseases such as indigestion.

4. The epidemic prevention system is not sound. Some farmers lack the concept of epidemic prevention, do not inject or inject vaccines or bacteria in time, and ignore the prevention of coccidiosis in summer and autumn.

5. Unfavorable management measures, such as dirty rabbit houses, moisture, and poor ventilation.

There are several ways to improve the survival rate of young rabbits:

1. The weight requirement of young rabbits at weaning. The speed of fattening depends largely on the speed of early weight gain. That is, it is closely related to the fattening period and the lactation period. All rabbits with large weaning weights gain weight faster during the fattening period and are more likely to resist the stress of weaning. The smaller the weaning weight, the more difficult it is to raise after weaning, and the slower the fattening weight gain. This requires improving the lactation ability of the mother rabbit, ensuring the supplementary feed for the young rabbits, and adjusting the weight of the young rabbits and the number of young rabbits the mother rabbit feeds.

2. Pay attention to feed problems. Many young rabbits develop digestive tract diseases after weaning, and the main reason is the feed. Because rabbits grow fast after weaning, but their digestive functions are not yet fully developed, a sharp contradiction is formed. Therefore, it is very important to prepare nutritious, easy to digest, and stress-preventing feed. Premix microecological preparations can be used to adjust the rabbit intestinal flora to reduce the stress response of young rabbits. The quality of feed raw materials must be strictly controlled, and attention must be paid to whether the feed raw materials are moldy.

3. Young rabbits are susceptible to infectious diseases, so we need to do a good job of epidemic prevention. Pay attention to daily disinfection, cleanliness and hygiene to reduce the occurrence of diseases. Onions, garlic and other medicinal plants can be added to the feed, which are good for disease prevention and growth promotion. At the same time, timely vaccination should not be ignored to ensure the safety of the rabbits.

4. Young rabbits have a habit of eating gluttonously, so the amount of food they eat must be limited. Feed them regularly, and reduce or increase the amount of food you feed them next time based on the amount of food left. Young rabbits grow fast and have a large appetite, so you must ensure they drink enough water every day.

The above are the factors that affect the survival rate of young rabbits and the methods to improve the survival rate of young rabbits. I hope it can be helpful to everyone! I wish all the young rabbits you raise can grow up healthily!

8. What are the factors that affect hydrolysis? Please explain in detail.

Heating promotes hydrolysis

Dilution promotes hydrolysis

Just remember these two points

9.What are the factors that affect impedance?

First, dielectric thickness. Increasing dielectric thickness can increase impedance, while decreasing dielectric thickness can reduce impedance. Different prepregs have different adhesive contents and thicknesses. The thickness after lamination is related to the flatness of the press and the procedure of the press plate. For any type of sheet used, it is necessary to obtain the producible dielectric layer thickness, which is conducive to design calculation. Engineering design, press plate control, and incoming material tolerance are the key to dielectric thickness control.

Second, line width. Increasing line width can reduce impedance, while reducing line width can increase impedance. Line width control requirements must be within a tolerance of +/-10% to better meet impedance control requirements. The gap in the signal line affects the entire test waveform. Its single-point impedance is too high, making the entire waveform uneven. Impedance lines are not allowed to be patched, and their gaps cannot exceed 10%. Line width is mainly controlled by etching control. To ensure line width, process compensation is performed on the engineering film based on the amount of etching side etching, photo-drawing error, and graphic transfer error to meet line width requirements.

3. Copper thickness. Reducing the line thickness can increase the impedance, while increasing the line thickness can reduce the impedance. The line thickness can be controlled by pattern plating or selecting the base copper foil of corresponding thickness.

10. What are the factors that affect castings?

The bed casting is made of high-quality high-strength cast iron HT250-300, which has strong tensile strength and long service life. The machine tool bed is widely used in the processing of parts and components in the instrumentation, electronics, light industry, standard parts, bearing industry, auto parts industry, etc., and is particularly suitable for non-ferrous metals. The production of the machine tool bed adopts a complete resin sand production line, and all kinds of machine tool bed castings are made of resin sand and lost foam casting. This process makes the castings have high dimensional accuracy, uniformity, no buckling, and no flash or burrs; the surface smoothness is close to precision casting, the internal structure is stable, and casting defects such as sand holes and pores are eliminated or reduced. The entire production process is three-level environmentally friendly and pollution-free. Bed casting: Because the gray cast iron has a high carbon content and is close to the eutectic composition, it has a relatively low melting point, good fluidity, and a small shrinkage rate, so it is suitable for casting complex structures or thin-walled castings. In addition, because graphite makes it easy to form chip breakage during cutting, the machinability of gray cast iron is better than that of steel. Factors affecting the quality of castings:

1. Design processability of castings. When designing, in addition to determining the casting geometry and size based on working conditions and metal material properties, the rationality of the design must also be considered from the perspective of casting alloy and casting process characteristics, that is, obvious size effects and solidification, shrinkage, stress and other issues, in order to avoid or reduce defects such as component segregation, deformation, and cracking of castings.

2. Have a reasonable casting process. That is, according to the structure, weight and size of the casting, the characteristics of the casting alloy and the production conditions, choose the appropriate parting surface and modeling, core making method, and reasonably set the casting ribs, chill, riser and pouring system, etc. to ensure the acquisition of high-quality castings.

3. The quality of raw materials used for casting. If the quality of metal furnace materials, refractory materials, fuels, fluxes, modifiers, casting sand, molding sand binders, coatings and other materials is not up to standard, it will cause defects such as pores, pinholes, slag inclusions, and sand adhesion in the castings, affecting the appearance and internal quality of the castings. In serious cases, the castings will be scrapped. The fourth is process operation. It is necessary to formulate reasonable process operation procedures, improve the technical level of workers, and ensure that the process procedures are correctly implemented.