Year: 2019

How to save Endangered species through mathematics?

It’s now possible to predict how likely an endangered species is to go extinct, with mathematical models acting as windows into the future. These models help scientists foresee how a population is likely to react to changes in the environment and therefore how likely it is to die out. As the sixth mass extinction event rumbles on, this represents a powerful tool in the arsenal of conservationists. However, accurate information about species in the wild is still crucial to inform these models and divine the fate of wildlife populations. A species’ risk of extinction depends on how many individuals in its populations can reproduce and how long they can survive. To design management programmes that can prevent extinction, it’s essential to understand how survival and reproductive rates change within a population as the environment changes. How rates of survival and reproduction within a population change with age for different species. Fernando Colchero, Author provided We know that the number of individuals surviving and reproducing – known collectively as a species’ demographic rates – vary each …

What kind of diet make you lives the longest? Meat or Vegetarian?

Our ability to live a long life is influenced by a combination of our genes and our environment. In studies that involve identical twins, scientists have estimated that no more than 30% of this influence comes from our genes, meaning that the largest group of factors that control how long a person lives is their environment. Of the many possible environmental factors, few have been as thoroughly studied or debated as our diet. Calorie restriction, for example, is one area that is being investigated. So far, studies seem to show that restricting calories can increase lifespan, at least in small creatures. But what works for mice doesn’t necessarily work for humans. What we eat – as opposed to how much we eat – is also a hot topic to study and meat consumption is often put under the microscope. A study that tracked almost 100,000 Americans for five years found that non-meat eaters were less likely to die – of any cause – during the study period than meat eaters. This effect was especially noticeable …

Does endurance exercise suppresses the immune system?

Does endurance exercise suppresses the immune system?

It is commonly believed that some forms of exercise, such as endurance events, suppress your immune system and leave you at risk of infections, like the common cold. However, our latest review of the evidence suggests that this is probably not true. In fact, exercise seems to boost the immune system. The idea that endurance exercise suppresses the immune system stems from research in the 1980s and 1990s. In these studies, competitors of endurance running events, such as the Los Angeles Marathon, were asked if they had symptoms of infections in the days and weeks after the race. Many did, leading to the idea that endurance exercise increases infection risk. An overlooked problem in many of these studies was that symptoms of “infections” were not confirmed in a lab, so it wasn’t known if they were genuine illness symptoms. More recent studies have shown that most symptoms reported after marathons are not real infections. Instead, the symptoms are caused by other factors, such as allergy. These earlier studies put the cause of the increased risk …

Timeline United States Immigration Policy

U1952 Chinese immigrants undergo an interrogation at Ellis Island. Bettmann/Corbi Quota System Upheld As the Cold War deepens, the U.S. government consolidates its immigration and naturalization laws into one comprehensive federal policy. The McCarran-Walter Act ends policies stemming from the late nineteenth century designed to exclude Asian immigrants. However, the bill upholds the ethnicity-based quota system for new immigrants that favored white Europeans, revising limitations to admit one-sixth of 1 percent of each group already in the United States. President Harry Truman vetoes the bill, citing discrimination against Asian immigrants and decrying the “absurdity, the cruelty of carrying over into this year of 1952 the isolationist limitations of our 1924 law.” Congress overrides him to pass it. 1954 Three undocumented Mexican immigrants held under arrest. Gamma-Keystone/Getty Images Eisenhower Launches ‘Operation Wetback’ The postwar period causes a swell of illegal immigration to the United States from Mexico, with an estimated three million undocumented Mexicans in the country working mostly in agricultural jobs at significantly lower wages than what American workers receive. Under growing public pressure to …