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  • https://arxiv.org/abs/2008.04927
    Could the Migration of Jupiter have Accelerated the Atmospheric Evolution of Venus?
    In the study of planetary habitability and terrestrial atmospheric evolution, the divergence of surface conditions for Venus and Earth remains an area of active research. Among the intrinsic and external influences on the Venusian climate history are orbital changes due to giant planet migration that have both variable incident flux and tidal heating consequences. Here, we present the results of a study that explores the effect of Jupiter's location on the orbital parameters of Venus and subsequent potential water loss scenarios. Our dynamical simulations show that various scenarios of Jovian migration could have resulted in orbital eccentricities for Venus as high as 0.31. We quantify the implications of the increased eccentricity, including tidal energy, surface energy flux, and the variable insolation flux expected from the faint young Sun. The tidal circularization timescale calculations demonstrate that a relatively high tidal dissipation factor is required to reduce the eccentricity of Venus to the present value, which implies a high initial water inventory. We further estimate the consequences of high orbital eccentricity on water loss, and estimate that the water loss rate may have increased by at least $sim$5% compared with the circular orbit case as a result of orbital forcing. We argue that these eccentricity variations for the young Venus may have accelerated the atmospheric evolution of Venus towards the inevitable collapse of the atmosphere into a runaway greenhouse state. The presence of giant planets in exoplanetary systems may likewise increase the expected rate of Venus analogs in those systems.
    ARXIV.ORG
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  • https://arxiv.org/abs/1810.05150
    Early evolution of purple retinal pigments on Earth and implications for exoplanet biosignatures
    We propose that retinal-based phototrophy arose early in the evolution of life on Earth, profoundly impacting the development of photosynthesis and creating implications for the search for life beyond our planet. While the early evolutionary history of phototrophy is largely in the realm of the unknown, the onset of oxygenic photosynthesis in primitive cyanobacteria significantly altered the Earth's atmosphere by contributing to the rise of oxygen ~2.3 billion years ago. However, photosynthetic chlorophyll and bacteriochlorophyll pigments lack appreciable absorption at wavelengths about 500-600 nm, an energy-rich region of the solar spectrum. By contrast, simpler retinal-based light-harvesting systems such as the haloarchaeal purple membrane protein bacteriorhodopsin show a strong well-defined peak of absorbance centered at 568 nm, which is complementary to that of chlorophyll pigments. We propose a scenario where simple retinal-based light-harvesting systems like that of the purple chromoprotein bacteriorhodopsin, originally discovered in halophilic Archaea, may have dominated prior to the development of photosynthesis. We explore this hypothesis, termed the 'Purple Earth,' and discuss how retinal photopigments may serve as remote biosignatures for exoplanet research.
    ARXIV.ORG
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    https://arxiv.org/abs/1810.05150
    Early evolution of purple retinal pigments on Earth and implications for exoplanet biosignatures
    We propose that retinal-based phototrophy arose early in the evolution of life on Earth, profoundly impacting the development of photosynthesis and creating implications for the search for life beyond our planet. While the early evolutionary history of phototrophy is largely in the realm of the unknown, the onset of oxygenic photosynthesis in primitive cyanobacteria significantly altered the Earth's atmosphere by contributing to the rise of oxygen ~2.3 billion years ago. However, photosynthetic chlorophyll and bacteriochlorophyll pigments lack appreciable absorption at wavelengths about 500-600 nm, an energy-rich region of the solar spectrum. By contrast, simpler retinal-based light-harvesting systems such as the haloarchaeal purple membrane protein bacteriorhodopsin show a strong well-defined peak of absorbance centered at 568 nm, which is complementary to that of chlorophyll pigments. We propose a scenario where simple retinal-based light-harvesting systems like that of the purple chromoprotein bacteriorhodopsin, originally discovered in halophilic Archaea, may have dominated prior to the development of photosynthesis. We explore this hypothesis, termed the 'Purple Earth,' and discuss how retinal photopigments may serve as remote biosignatures for exoplanet research.
    ARXIV.ORG
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  • https://simple.wikipedia.org/w/index.php?title=Stellar_evolution&oldid=9946517
    Stellar evolution
    Stellar evolution is the study of how a star changes over time. Stars can change very much between when they are first created and when they run out of energy. Because stars can produce light and heat for millions or billions of years, scientists study stellar evolution by studying many different stars in different stages of their life. The stages in a star's life are: protostar, main-sequence star, red giant and compact star: either white dwarf followed by black dwarf, neutron star or black hole. How a star is born A star starts its life as a cloud of dust and gas called a nebula. This is pulled together by gravity which causes it to heat up. It also starts to spin and to look like a ball. When it gets hot enough, it starts to release energy through nuclear fusion, changing hydrogen to helium. This makes it shine very brightly and become what astronomers think of as a main-sequence star. It may stay a main-sequence star, looking about the same, for billions of years. The details of a main-sequence star are based on its mass. The mass is often measured in terms of the Sun's mass, or a solar...
    SIMPLE.WIKIPEDIA.ORG
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  • https://unctad.org/topic/trade-analysis/chart-10-may-2021
    Evolution of the world's 25 top trading nations
    Discover in less than one minute the evolution of the world's main trading nations. Trade has significantly expanded in the last four decades. In 1979, trade represented 36% of global GDP and by 2019 the figure had grown to 60%.
    UNCTAD.ORG
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  • http://arxiv.org/abs/astro-ph/0504097
    Simulating the joint evolution of quasars, galaxies and their large-scale distribution
    The cold dark matter model has become the leading theoretical paradigm for the formation of structure in the Universe. Together with the theory of cosmic inflation, this model makes a clear prediction for the initial conditions for structure formation and predicts that structures grow hierarchically through gravitational instability. Testing this model requires that the precise measurements delivered by galaxy surveys can be compared to robust and equally precise theoretical calculations. Here we present a novel framework for the quantitative physical interpretation of such surveys. This combines the largest simulation of the growth of dark matter structure ever carried out with new techniques for following the formation and evolution of the visible components. We show that baryon-induced features in the initial conditions of the Universe are reflected in distorted form in the low-redshift galaxy distribution, an effect that can be used to constrain the nature of dark energy with next generation surveys.
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  • https://arxiv.org/abs/1208.4444
    On the dynamical evolution of 2002 VE68
    Minor planet 2002 VE68 was identified as a quasi-satellite of Venus shortly after its discovery. At that time its data-arc span was only 24 days, now it is 2,947 days. Here we revisit the topic of the dynamical status of this remarkable object as well as look into its dynamical past and explore its future orbital evolution which is driven by close encounters with both the Earth-Moon system and Mercury. In our calculations we use a Hermite integration scheme, the most updated ephemerides and include the perturbations by the eight major planets, the Moon and the three largest asteroids. We confirm that 2002 VE68 currently is a quasi-satellite of Venus and it has remained as such for at least 7,000 yr after a close fly-by with the Earth. Prior to that encounter the object may have already been co-orbital with Venus or moving in a classical, non-resonant Near-Earth Object (NEO) orbit. The object drifted into the quasi-satellite phase from an L4 Trojan state. We also confirm that, at aphelion, dangerously close encounters with the Earth (under 0.002 AU, well inside the Hill sphere) are possible. We find that 2002 VE68 will remain as a quasi-satellite of Venus for about 500 yr more and its dynamical evolution is controlled not only by the Earth, with a non-negligible contribution from the Moon, but by Mercury as well. 2002 VE68 exhibits resonant (or near resonant) behavior with Mercury, Venus and the Earth. Our calculations indicate that an actual collision with the Earth during the next 10,000 yr is highly unlikely but encounters as close as 0.04 AU occur with a periodicity of 8 years.
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  • https://arxiv.org/abs/1703.03864
    Evolution Strategies as a Scalable Alternative to Reinforcement Learning
    We explore the use of Evolution Strategies (ES), a class of black box optimization algorithms, as an alternative to popular MDP-based RL techniques such as Q-learning and Policy Gradients. Experiments on MuJoCo and Atari show that ES is a viable solution strategy that scales extremely well with the number of CPUs available: By using a novel communication strategy based on common random numbers, our ES implementation only needs to communicate scalars, making it possible to scale to over a thousand parallel workers. This allows us to solve 3D humanoid walking in 10 minutes and obtain competitive results on most Atari games after one hour of training. In addition, we highlight several advantages of ES as a black box optimization technique: it is invariant to action frequency and delayed rewards, tolerant of extremely long horizons, and does not need temporal discounting or value function approximation.
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  • https://ui.adsabs.harvard.edu/abs/1985AREPS..13..201W
    The magma ocean concept and lunar evolution
    The model of lunar evolution in which the anorthositic plagioclase-rich oldest crust of the moon is formed over a period of 300 Myr or less by crystallization as it floats on a global ocean of magma tens or hundreds of km thick is examined in a review of petrological and theoretical studies. Consideration is given to the classification of lunar rocks, the evidence for primordial deep global differentiation, constraints on the depth of the molten zone, the effects of pressure on mineral stability relationships, mainly-liquid vs mainly-magmifer ocean models, and the evidence for multiple ancient differentiation episodes. A synthesis of the model of primordial differentiation and its aftereffects is presented, and the generalization of the model to the earth and to Mars, Mercury, Venus, and the asteroids is discussed.
    UI.ADSABS.HARVARD.EDU
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  • https://arxiv.org/abs/0710.4003
    YREC: The Yale Rotating Stellar Evolution Code
    The stellar evolution code YREC is outlined with emphasis on its applications to helio- and asteroseismology. The procedure for calculating calibrated solar and stellar models is described. Other features of the code such as a non-local treatment of convective core overshoot, and the implementation of a parametrized description of turbulence in stellar models, are considered in some detail. The code has been extensively used for other astrophysical applications, some of which are briefly mentioned at the end of the paper.
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  • ary-algorithm/

    #include <iostream>
    #include <string>
    #include <vector>
    #include <algorithm>
    #include <random>
    #include <chrono>

    using namespace std;

    // random generator function:
    int myrandom (int i) { return std::rand()%i;}


    int main () {

    // seed the random number generator with a constant value:
    srand( unsigned (time(0)) );

    const string target = "Hello World!"; // target string we are trying to match

    const int populationSize = 500; // population size of our genetic algorithm

    vector<string> population; // vector to store our population of strings

    int generation = 0; // current generation number

    // create a random starting population of strings:

    for (int i=0; i<populationSize; i++) {

    string str;

    for (int j=0; j<target.length(); j++) {

    char c = 97 + rand() % 26; // generate a random lowercase character from 'a' to 'z'

    str += c;

    }

    population.push_back(str); // add the generated string to the population vector

    }

    while (true) { // loop until we find the target string

    cout << "Generation: " << generation++ << endl;

    for (int i=0; i<population.size(); i++) { // loop through each member of the population

    cout << "String: " << population[i] << "\t\tFitness: " << fitness(population[i]) << endl;

    if (population[i] == target) { // check if this member is equal to the target string

    cout << "Target Reached!" << endl;
    return 0; // exit program if target is reached

    }
    }

    vector<string> newPopulation;// create a new empty vector for our new generation of strings

    for (int i=0 ; i<population.size(); i++) {// loop through each member of the current population

    string parent1 = selection(population);// select two parents using tournament selection
    string parent2 = selection(population);

    vector<string> children = crossover(parent1, parent2);// perform crossover between parents and generate two children
    mutation(children[0]);// perform mutation on both children mutation(children[1]); newPopulation.push_back(children[0]);// add both children to the new generation's population newPopulation.push_back(children[1]); } population = newPopulation;// replace old generation's population with the new one } return 0;}

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  • Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive. During its life, a star will pass through several stages, fusing lighter elements into heavier ones in successive nuclear reactions. These reactions release energy, which allows the star to radiate light and heat into space. As it ages, a star will move through different stages, including main sequence, red giant, and white dwarf. In some cases, stars may even end their lives as supernovae or neutron stars.

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  • Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star. Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star, but as the preponderance of hydrogen gets used up, more and heavier elements are created by fusion processes in layers around the core. The outflow of energy from the core causes it to gradually expand and cool over time, thereby transforming it into a red giant. Stars with at least half to three-quarters of the mass of our Sun will expand further into a supergiant phase before running out of fuel and collapsing into an incredibly dense white dwarf. Stars with greater than three solar masses will continue to collapse until they become dense enough to begin thermonuclear fusion in their cores; these are known as supernovas. Finally, stars that are even more massive will be able to sustain nuclear fusion in their cores even after they collapse, forming neutron stars or black holes depending on their mass and rotation rate.

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  • Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive. During its life, a star will pass through several stages, such as protostar, main-sequence star, red giant and white dwarf. The more massive stars will also go through supernova and neutron star stages. As it ages, a star's temperature and luminosity will change, and it may also undergo pulsations and mass loss.

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  • Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive. During its life, a star will pass through several stages, such as a protostar, main-sequence star, red giant and white dwarf. During each stage, different nuclear reactions take place in the core of the star, causing it to heat up or cool down and change in luminosity and size. Eventually, all stars will end their lives by either exploding as supernovae or collapsing into black holes.

    By: ChatGPT AI
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  • Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive. During its life, a star will pass through various stages, such as protostar, main-sequence star, red giant, and white dwarf. The energy produced by stars comes from nuclear fusion reactions in which hydrogen is converted into helium. As a star ages, it will eventually exhaust its supply of hydrogen fuel and move on to other elements in its core. This process leads to changes in stellar structure and luminosity as well as the eventual death of the star.

    By: ChatGPT AI
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  • Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive. During its life, a star will pass through various stages, such as a protostar, main-sequence star, red giant, and white dwarf. Each stage is characterized by different properties such as luminosity and temperature. As a star ages, it will also undergo nuclear fusion reactions in its core that produce heavier elements from lighter ones. These heavier elements are then released into space when the star dies, enriching the interstellar medium with new material.

    By: ChatGPT AI
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  • Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive. During its life, a star will pass through several stages, such as a protostar, main-sequence star, red giant, and white dwarf. As it evolves, a star will undergo nuclear fusion in its core and produce energy in the form of radiation. This radiation will cause the star to expand and contract in size as it moves through different stages of its life cycle.

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  • -of-the-web

    The evolution of the web began in 1989 when Tim Berners-Lee proposed the idea of a global hypertext project. This was the first step towards creating the World Wide Web. In 1991, Berners-Lee and his team at CERN released the first web browser, which allowed users to navigate through documents that were linked together via hypertext. This was the beginning of what we know today as the internet.

    In 1993, Marc Andreessen released Mosaic, which was the first graphical web browser and allowed users to view images and videos on websites. This was a major breakthrough in web technology and led to a surge in internet usage.

    The late 1990s saw a number of important developments in web technology. Netscape Navigator became one of the most popular browsers and HTML 4 was released, which introduced new features such as tables and frames. Java applets also became popular during this time, allowing developers to create interactive websites with dynamic content.

    In 2000, Microsoft released Internet Explorer 6, which became one of the most widely used browsers for many years afterwards. The same year also saw the release of XML, which allowed developers to structure data more effectively than HTML.

    The early 2000s saw a number of important developments in web technology including AJAX (Asynchronous JavaScript And XML), which allowed for faster loading times on websites; CSS (Cascading Style Sheets), which allowed developers to separate content from design; and RSS (Really Simple Syndication), which made it easier for users to keep up with their favorite websites.

    The mid-2000s saw an explosion in social media usage with sites such as Myspace and Facebook becoming hugely popular amongst internet users. This period also saw an increase in mobile device usage with smartphones becoming commonplace by 2010. In response to this trend, responsive design techniques were developed that allowed websites to adapt their layout depending on the device they were being viewed on.

    Today, web technology is constantly evolving with new technologies such as HTML5 being developed all the time. Web development is now much more complex than it was when it first began but it has come a long way since 1989 when Tim Berners-Lee proposed his idea for a global hypertext project!

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  • The first known use of the word "evolution" in English was in 1679, when it was used by Thomas Browne in his book Religio Medici. The term had been used earlier by French philosopher and mathematician René Descartes (1596-1650) and German naturalist and physician Georges-Louis Leclerc, Comte de Buffon (1707-1788). In the 19th century, Charles Darwin popularized the concept of evolution through his work On the Origin of Species. Since then, evolutionary theory has been widely accepted as a scientific explanation for the diversity of life on Earth. Evolutionary biology is now a major field of study, with researchers exploring topics such as genetic drift, natural selection, speciation, and adaptation.

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  • Tom Hanks Evolution
    Tom Hanks Evolution 1980-2022 #Shorts.
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  • A new supercomputer simulation animates the evolution of the universe
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  • The Insane Evolution of the Woolly Rhino
    Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube.
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