There are many things in the world that we don’t know, and they are all kinds of strange... Below are the popular science articles I compiled for you, I hope you like them.
Popular science articles: The dragon's blood tree is in bloom
The night is full of autumn flowers with dew, in the Moon-Wang Tower, at the end of the Yanyu Bridge, the fragrance of the world is filled with sorrow.
This life is destined to be both long and short? There are endless giant trees, graceful trees, and the ecstasy of the dark fragrance of dragon's blood.
The fragrant dragon blood tree Dracaena fragrans (fragrans, meaning, fragrant) in the Dragon Blood Tree Garden of Xishuangbanna Tropical Botanical Garden is blooming in large numbers. The fragrance is rich and refreshing, and the fragrance is especially strong at night.
Dracaena, also known as Brazilian wood, is a species of the genus Dracaena in the Asparagaceae family. It is a flowering plant native to Africa, from Sudan in the north to Mozambique in the south, and to C?te d'Ivoire, southwest to Angola, grows in highlands with an altitude of 600-2250m.
Brazil wood has neat and graceful plant shape, wide, glossy and green leaves. It is a famous new generation indoor foliage plant. It can be used in small and medium-sized pots to decorate study rooms, living rooms, bedrooms, etc., making it look elegant and unique; large and medium-sized plants can be placed in halls, conference rooms, offices, etc., and can be enjoyed for a long time, giving them an exotic feel; especially the Brazilian wood planted at different heights, the branches and leaves grow The clear layers can also give people the meaning of "step by step".
Brazil wood is an evergreen tree that can reach a height of more than 6 meters in its place of origin. Generally, the height of potted plants is 50-100cm. It has an upright trunk and sometimes branches. The leaves are clustered on the top of the stem, oblong-lanceolate, without petioles; the leaves are 40-90cm long, 6-10cm wide, curved into an arc, the leaf margins are undulating, and the leaf tips are slightly blunt; they are bright green and shiny. Flowers in spikes, small, yellow-green, fragrant.
Brazil wood is not produced in Brazil, but is native to Africa. It has been widely introduced and cultivated in my country in recent years. Brazilian wood is mostly propagated by cuttings. After many years of cultivation, if the plant is too tall or the lower leaves of the stem have fallen off, and the plant shape is poor, it can be pruned, and the cut branches can be used as cutting materials.
Popular Science Articles: Unearthed Paleontological Fossils
In the eyes of paleontologists, the scattered skeleton fossils buried in the loess are not just a pile of dead things, they are Just like scattered puzzle pieces, when put together, it may be a flying dinosaur, or a huge whale, or it may just be a piece of primitive human skull, or a small insect at the origin of life. But biologists don’t have sharp eyes, so how do they know where there are fossils? Are there any instruments that can detect fossils in the ground? How do they know the names of these creatures?
Discovery
Paleontology is an ancient and traditional basic science. It studies the fossils of organisms that have appeared on the earth to understand the origin, evolution, extinction, recovery of organisms in geological history and their relationship with the environment at that time. Relationship. It generally goes through several stages such as field investigation, fossil excavation, specimen repair, scientific research, morphological restoration and museum exhibition.
Before fieldwork, you must first select the region and stratum. For example, to study pterosaurs and dinosaurs, you must look for fossil clues in the strata of the Mesozoic Era. The Mesozoic Era includes the Triassic, Jurassic, and Cretaceous periods, and Reptiles such as pterosaurs and dinosaurs only lived in the Mesozoic Era, so their fossils cannot be found in the sediments of the later Cenozoic Era and the earlier Paleozoic Era.
While in the field, we not only need to search, verify and confirm the fossil locations recorded in geological documents, but also visit local folks to investigate and verify whether fossils have been found in this area and when they were discovered. On this basis, we look for possible fossils. Therefore, the search for fossil clues in the wild and the determination of excavation sites do not rely on advanced instruments and equipment.
Determining the best excavation site is mainly based on the number of fossils exposed on the surface and the rock layer where the fossils are buried to determine whether the fossils in this rock layer are complete or relatively complete individuals buried in situ, or whether they have been Are the scattered bones that were transported and buried in other places an enriched burial caused by cluster death, or a small amount of burial caused by normal death. For example, the Jehol biota in western Liaoning is different from the dinosaur fauna in Laiyang, Shandong. The former occurs in lake sedimentary shale and is gray-black shale, which means that they were formed in a deep lake still water reducing environment. This environment The fossils found in the shale are generally complete individuals, and judging from the large number of volcanic ash interlayers on the profile, the volcanic activity here is very frequent. The death of these creatures should be related to catastrophic events caused by volcanic eruptions. That is to say, they died in abnormal clusters. As long as the layer and location of fossil outcrops are found, it means that there are relatively abundant and complete fossils of all types buried. Therefore, as long as we find an outcrop of even just one skeleton, we can do it without hesitation. The site was identified as the best location to explore. The latter is buried in sand and mudstone formed by alluvial rivers. It is a chaotic accumulation of purple-red gravelly sand and mudstone. It is a type of sedimentation formed by debris flows in an oxidative environment. Most of the fossils in this type of sediment are scattered and preserved, so it is best to The best fossil location is to choose the point with the most fossil outcrops in the same layer. The more outcrops, the richer the fossils.
Collection
It is important to find fossils in the wild, but it is even more important to collect the fossils found intact. Depending on the lithology of the strata where the fossils occur, the burial environment, etc., different collection methods can be adopted, such as the boxing method, the gypsum bag method, and the "sandwich biscuit method".
Most of the large dinosaur bones and other fossils scattered in the river alluvial burial environment, such as the dinosaur fauna in Laiyang, Shandong, are collected using the gypsum package method. This method is to make grooves downward around the fossil and surrounding rock. When it exceeds the fossil, it shrinks inward to make it become a mushroom shape. Pour gypsum on top, cover it with sack sheets, press it tightly, and then pour thicker gypsum. , smooth and compact it, add wooden boards or wooden sticks, wait for the gypsum to heat and harden, smash it into the steel drill to separate it from the rock layer and turn it over, and register it with a unified number.
For complete fossil skeletons like those buried in the Huxiang shale in western Liaoning, the "sandwich biscuit method" must be used. Since the shale containing the fossils of the Jehol biota in western Liaoning has many fissures and contains volcanic ash components, the rock layer is very soft after being soaked in groundwater for a long time. After being collected, the volcanic ash will quickly dehydrate, causing the rock layer to deform and break into powder. Therefore, Collecting such specimens has always been a problem. But using the sandwich biscuit method, more than ten specimens can be collected in a day without damaging the fossils at all. This method involves determining the scope of discovery of individual fossils. Use a knife to cut gaps and dig out small grooves around the fossils and surrounding rocks. Place soft paper around the specimen along the grooves and wrap it tightly with transparent tape to separate the parts under the fossil layer. For a relatively loose layer, move the specimen along the layer to the prepared wooden board, then put soft paper on it, press it on another wooden board, wrap it with tape, leaving only a small gap for evaporated water vapor, and finally slowly dehydrate and dry in the shade.
Fossil repair is one of the most critical links in paleontological research. Fossil repair means exposing the fossil bones as much as possible without damaging the fossil. For example, when repairing fossils collected by the "sandwich biscuit method", you should open the thoroughly dried specimens from the front, and repair them sequentially along the exposed bones starting from the upper layer of the bones found in the wild. Some of the specimens also contain dinosaurs or birds. Soft tissue structures such as feathers and wing membranes of pterosaurs must be carefully repaired under a microscope. You can even use X-ray scanning before repair to confirm the distribution of bones to guide the repair.
For fossils collected in plaster bags, in order to determine the size of the fossils and the need for groove collection during excavation, most of the fossil bones on the upper layer have been exposed. Only repairing from the lower layer will speed up the repair progress. . During the repair process, use a saw blade to saw off the hard plaster surrounding the plaster wrap to expose the surrounding rock, and then clean it downwards in sequence until all the surrounding rock around the skeleton is removed. During the cleaning process, glue should be used at any time to reinforce the bones that are naturally broken in the rock formation.
Naming
The most basic research method in paleontology is the detailed description of fossil morphology. Although many are qualitative descriptions, they are the basis for all other research. On the basis of traditional morphological description and taxonomic research, the systematic evolutionary position of this biological type is analyzed, and its origin and evolution are discussed. With the continuous emergence of new technologies and methods, many new technologies are gradually applied to the field of paleontology. For example, high-precision CT scanning and three-dimensional reconstruction technology can clearly understand some of the internal morphological structures of fossil organisms without damaging the fossils, such as Complex brain-cranial system, etc. The application of electron microscopy and microslicing technology can observe the microstructure of fossil bones and understand the age and ontogeny of organisms.
If fossil research proves that it is a new species that has never been discovered, then paleontologists will name the fossil. The naming of paleontological organisms also uses the binomial method, such as Avatar Ikaran Pterosaur. The Latin name is preceded by the genus name, followed by the species name. The genus and species names are always in italics. When translated into Chinese, the species name "Avatar" comes first and the genus name "Icaran Pterosaur" comes after. The genus name can be used alone. We can call it "Icaran Pterosaur", but the species name cannot be used alone. It must be It must be together with the genus name. There are several main sources for the etymology of paleontological naming, including: names of fossil origins, such as Tianshan Hami Pterosaur; personal names, which commemorate some historical figures, scientists who have made important contributions, or discoverers of fossils, such as the sage Confucius Bird; fossils Characteristics, such as the spinous nose Qingdaoosaurus, the species name comes from the long "spiny nose" on the top of the dinosaur's head. Among these names, the genus name is unique, and the species name can be repeated multiple times.
Based on the study of fossil morphology, we know the individual size of this creature, the shape of its skull and teeth, the size ratio of each bone in the body, and even the shape of preserved soft tissues such as feathers, as well as their According to the living environment and other information, the artist will use the principle of "discussing the present with the past" and draw morphological restoration diagrams and ecological restoration diagrams of fossil organisms based on some characteristics of living organisms and similar environmental backgrounds.
Popular science articles: Housework may save your life
I have never been keen on physical exercise. My work basically consists of sitting in front of the computer for several hours a day, occasionally talking to others, and of course sitting. I usually sit and watch TV at night, unless I go out. When I go out, I usually take a taxi first and then sit down to eat. Sitting is my normal state, and I probably sit for fifteen or sixteen hours a day (the remaining eight hours are spent lying down and sleeping).
All research evidence shows that low levels of physical activity are bad for your health. A few years ago, the well-known medical journal "The Lancet" published a series of review articles pointing out that low physical activity levels are the fourth largest killer of human health today. According to the World Health Organization, 10% (5 million people) of global deaths each year are directly attributable to low levels of physical activity.
My problem is that I am fully aware of the dangers of inactivity but cannot motivate myself to stand up and move. For me to actually engage in physical activity, I need a reason besides the physical benefits it provides. It’s not that I’m physically disabled and can’t exercise normally, but I’m mentally resistant to it. For example, when my son was in Beijing, I got up an hour earlier every morning and rode a 5-kilometer bike with him to school. I would have a cup of coffee at a cafe near his school, then ride 5 kilometers home to my office, which was only 500 meters away from where I lived. Obviously, cycling is my sport? Because it’s also done while sitting down! But it’s definitely a sport. And when you're riding with a 17-year-old boy, the speed is pretty impressive. On the road, we often try to race against the e-bike flow, at which point my heart rate is most likely reaching physical training levels.
The key point here is that I enjoy riding every morning for a different reason: to be with my son. We often travel against the wind, and sometimes encounter snowstorms, so the two of us don't talk much. But mostly he would tell me about what he was doing in school, his plans for the future, and all sorts of meaningless manly stuff like the Ferrari 458 Italia and the Lamborghini Aventador. ) Which one is better? We can’t own either one, but it’s important for men to figure it out (the Lamborghini Aventador is better, by the way). During the last three months of his stay in Beijing, he transferred to another school, 17 kilometers away from our residence. Yet I still ride to school with him. We woke up 30 minutes earlier than before. There is no cafe near the new school. Every day when he enters the school gate, I turn around and go back.
In those few months, when I went to work every day, I had already cycled almost a full marathon. For me, though, it’s not about sports. My son is now studying in the UK. I still ride a bicycle every day, but only from my residence to the office. The total daily exercise is only 10 minutes, and my speed and heart rate are not much better than when I sit and work. . I never thought that I should change direction and ride at three times the normal speed for half an hour until I was sweating profusely and then come back. My son is not with me, so riding is just a sport for me, and I don’t have enough motivation to do it. I understand all the statistics and biology surrounding low physical activity and the benefits of exercise and fitness, but this inertia is still so strong. So what will happen to people who don’t understand the benefits of exercise?
However, how healthy outdoor exercise is, there is another issue for people living in Beijing to consider. The problem is air pollution. Everyone on the planet knows that Beijing’s air quality is terrible. I once rode a marathon every day for three months. Is this really good for my health? Considering the air quality while riding, the answer may be no.
So it seems like we are losing no matter what. If you're inactive, you can suffer from a variety of physiological and health problems associated with low levels of physical activity. However, if you exercise, the air quality in much of eastern China may make it more dangerous than not exercising. So what to do? The answer, at least for Chinese men, is housework. This answer must be very pleasant to most women in China. Does your husband never do his share of housework at home? It might be worth pointing out to them that doing more housework can reduce their risk of various non-communicable diseases, including cancer.
The evidence for this assertion comes from an article published in the journal PLOS One in 2013. Researchers studied 4,000 middle-aged and elderly Chinese people. Benefits of doing housework. During the screening process, 1,133 subjects who already had heart disease, stroke, cancer or diabetes were eliminated, and the final valid data came from 2,867 healthy individuals. They recorded how much physical activity the subjects spent each day, ranging from leisure activities such as sports and walking to gardening and mowing lawns. In addition, the researchers recorded how much time the subjects spent doing indoor chores and home repairs. The researchers then followed the subjects for 11 years, during which 452 people died, 185 of whom died of cancer. After adjusting the data for relevant factors such as age, education level and lifestyle, they found that individuals who performed more and heavier housework had a significantly lower risk of death than those who performed little or no housework. The risk ratio between the two is 0.72, which means the risk is reduced by approximately 30%. The effect is huge. However, the reduction in disease risk may have a variety of causes besides the direct impact of housework. For example, people who do more indoor housework may also engage in more sports or outdoor leisure activities.
Perhaps people who do no housework at all are actually severely obese, so their mortality is related to obesity rather than more or less housework. However, after adjusting for the effects of body composition (body mass index), living status (married, single, etc.) and outdoor leisure activities, the risk ratio between the two only became 0.71, indicating that the other factors mentioned above have an impact on housework and outdoor leisure activities. There was no effect on the relationship between all-cause mortality. The impact of housework on cancer risk is even more pronounced. Study participants who did a lot of housework had half the risk of cancer as those who did almost no housework (a hazard ratio of 0.52). Engaging in moderate and light-intensity housework had little impact on the risk of death.
There are two findings in this study that are particularly surprising. One is that the impact of housework goes far beyond leisure activities, including sports. The second is that the significant impact of housework on health is only seen in men. For the women surveyed in the study, there was no correlation between the amount of housework and death from any cause or from cancer! So, this is really good news for women. You can turn over all the housework to your husband without worrying about increasing your risk of death or cancer; your husband will do all the housework and live longer as a result. In my opinion, there are two additional benefits. Compared to physical exercise, housework has a different purpose; it is actually a job. I'm more likely to stick to housework than pure exercise, like I can ride a long way to school with my son without him being around without wanting to ride more. An added bonus is that by definition housework is done indoors, so it's an exercise you don't have to expose yourself to Beijing's air pollution.
This sounds so good that it seems unreal. And that's probably not true. As with all such studies, it is very important to remember that despite the large sample size (nearly 3,000 people) and the long follow-up period (about 10 years), the result obtained is only a correlation. Is there not necessarily a causal relationship between increases in housework and lower mortality? No matter how convincing the data may seem, or how consistent they may be with other studies. For example, a person's commitment to housework is likely to reflect his overall positive attitude toward life. If a person keeps his home in order, it may mean that he has a positive and serious attitude towards other things. Perhaps their overall attitude toward life influenced other things they did, thereby reducing their risk of death. These people may eat healthier, have a wider circle of friends, be more enthusiastic about community activities, etc. All of the above points are thought to be related to longevity and the risk of non-communicable diseases, including cancer. Housework may be just one indicator of other factors that really contribute to mortality risk. So if you decide to start taking on a lot of household chores but don't make any changes in other related things, the end result may just be that you have a cleaner home. The effect of household chores on mortality risk would be weak and possibly negative. Perhaps people who are willing to do housework and home repairs have a specialized set of skills that people who don't do housework do not. If you suddenly start doing various household chores without the corresponding experience, you may face a higher risk of accidents, such as falling from a ladder, electric shock, etc. In fact, if you already have a fairly negative view of things, suddenly taking on a lot of housework every week is less likely to make you have a more optimistic view of life, and it's likely to make the situation worse. What we really need is a randomized controlled trial in which people are randomly divided into two groups, one group is assigned more housework and the other is not assigned, and then their risk of death is followed. Only then can we determine whether correlations in observational studies are causal.