Could thermodynamic fluctuations have led to the origins of life

first_imgBrogioli suggests that this drift represents an early form of evolution that took place before membranes began to enclose chemical systems; after this time, the membranes would have assumed responsibility for defining entities in competition with one another, allowing selection to take place. If thermodynamic fluctuations did play the role of selection in early life, it would overcome the problem of requiring replicating chemicals and the membranes that enclose them to emerge simultaneously.In his paper, Brogioli looks at replication from a kinetics perspective, in which the kinetic counterpart of the inheritance of mutations is the presence of multiple stationary states, i.e., different lines of mutations can be present simultaneously, and their offspring inherit mutations. He shows that chemical systems that can pass mutations on to offspring can be thought of as systems with multiple stationary states, thus having the property of chemical marginal stability. These systems differ from a simple “self-catalytic” system (e.g., a purely chemical system) that merely produces offspring without transmitting mutations; the kinetic counterpart would be initial states that all lead to only one stationary state. As an analogy of a marginally stable system, Brogioli considers the mechanical example of a marble on a flat surface, where any point on the surface is a stationary point. If the marble is disturbed, it reaches a different stationary point rather than returning to its original position, since there is no restoring force. Likewise, spontaneous concentration fluctuations can enable a chemical system to inherit a variety of mutations from its parent system, and any of these mutations can be considered stable.Brogioli discovered the drift motion by mathematically studying the thermodynamic fluctuations over time. He found that, if two replicases R1 and R2 are present, the most efficient replicase, say R2, begins increasing in number and becomes dominant. In volumes with a higher concentration of R2, more replications will occur, and a larger fraction of them will be R2. Afterward, an even more efficient replicase can arise due to random mutations, and its concentration will increase, and so on.At the moment, the drift has been confirmed only by numerical calculations, and must be regarded as still theoretical. Brogioli notes that most chemical systems that have a replicase do not possess chemical marginal stability, and therefore are not affected by thermodynamic fluctuations. However, his study shows that the existence of a chemical system that is marginally stable and can undergo spontaneous evolution is possible. Investigating this theory further could have extremely important revelations. The demonstration of a marginally stable chemical system in the lab would not only be the first experiment in which a chemical system undergoes spontaneous evolution, but also the first in vitro model of a chemical reaction that leads to life.”Currently, no replicase that can self-sustain its replication has been created, but replication of RNA polymers can be obtained by ligation of short oligonucleotides,” Brogioli said. “This is a way [to find a chemical system could have marginal stability]. Another possibility is to create a more abstract system, in which replication is accomplished by an enzyme, and the activity of the enzyme is affected by the presence of one of the replicated polymers. Obviously, this is only a proof of principle of marginal stability and evolutionary drift, but not a realistic reproduction of the origin of life. The most interesting possibility is to consider the reactions proposed by the metabolism-first theories. In those theories, no replicating polymer was involved in abiogenesis, but only small molecules constituting some kind of metabolic network. The target is to find a very simple reaction that can be marginally stable.” (Left) Self-catalysis vs. (right) replication with inheritance in terms of kinetics: In the case of self-catalysis, all the initial states eventually lead to the same stationary state. In the case of replication with inheritance, the initial states lead to different stationary states on the stationary-state curve. The blue arrows show that the motion along the stationary-state curve is a drift pointing toward the increase of the most active replicase, R2. Image copyright: Doriano Brogioli. ©2010 The American Physical Society. In the field of abiogenesis, scientists are currently investigating several ways in which life could have arisen from non-living matter. Generally, any theory of abiogenesis should account for two important aspects of life: replication (the ability to transmit mutations to offspring) and metabolism (the chemical reactions required for vital activities such as breaking down food). Although these two characteristics help to provide a working definition of life, more recently scientists have emphasized the importance of another key feature required for Darwinian evolution: selection, or the replication of mutations that provide an evolutionary advantage. More information: Doriano Brogioli. “Marginally Stable Chemical Systems as Precursors of Life.” Physical Review Letters 105, 058102 (2010). DOI: 10.1103/PhysRevLett105.058102 What came first in the origin of life? A study contradicts the ‘metabolism first’ hypothesis Citation: Could thermodynamic fluctuations have led to the origins of life? (2010, August 16) retrieved 18 August 2019 from Explore further “The basic problem of abiogenesis is finding the first living entity that generated from non-living matter,” Doriano Brogioli, a physicist from the University of Milan-Bicocca, told “But what is the definition of life: is it replication, or metabolism, or simply self-catalysis? I think that it is not simply a matter of definition: what is necessary is ‘evolution,’ even if the entity that undergoes (or performs) evolution is not a classical living entity. After evolution starts, it can reach whatever complex structures: from a cell, evolution creates trees, whales, birds, ants, and all the prodigious current living world.”Purely chemical systems may possess the ability to replicate and metabolize, but scientists have found that chemical systems by themselves do not undergo selection; more active molecules are not replicated more than others, and useful individual mutations are not inherited by the offspring. Therefore, researchers have suggested that some kind of physical process is likely required to introduce competition among chemical systems and generate the selective pressure required for evolution. “Three features are needed for evolution: inheritance, mutation and selection,” Brogioli said. “Single molecules can replicate other molecules, including other copies of themselves, and can undergo mutations. But in a solution with replicases, each replicase replicates whatever it finds, including non-active molecules or less active replicases. Selection is not active. The reason is that (traditional) chemistry favors selfish molecules: the molecule that is more able to be replicated increases its concentration. In order for selection to take place, there must be a physical process. Confination due to membranes is the current way used by living organisms. But it is hard to believe that a complex structure like a cell can form spontaneously, since the replicating polymers must form together with the membranes themselves. This problem is found in all the theories of abiogenesis, including the RNA-world and the metabolism-first theories.”Brogioli has taken a unique approach to satisfying the requirement for selection by proposing that the answer may lie in thermodynamic fluctuations. These fluctuations, which are changes in the number of molecules in a given volume due to thermal motions, may allow selection to become effective, leading to the increase in molecules having an evolutionary advantage. By investigating some chemical systems that possess a feature that he calls “chemical marginal stability,” Brogioli has shown that thermodynamic fluctuations induce not only a random walk, but a drift directed toward increasing replication efficiency. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Researchers build fully mechanical phonon laser

first_img Explore further More information: Phonon Lasing in an Electromechanical Resonator, Phys. Rev. Lett. 110, 127202 (2013) DOI:10.1103/PhysRevLett.110.127202AbstractAn electromechanical resonator harboring an atomlike spectrum of discrete mechanical vibrations, namely, phonon modes, has been developed. A purely mechanical three-mode system becomes available in the electromechanical atom in which the energy difference of the two higher modes is resonant with a long-lived lower mode. Our measurements reveal that even an incoherent input into the higher mode results in coherent emission in the lower mode that exhibits all the hallmarks of phonon lasing in a process that is reminiscent of Brillouin lasing. Journal information: Physical Review Letters Citation: Researchers build fully mechanical phonon laser (2013, March 19) retrieved 18 August 2019 from Quantum leap for phonon lasers The world has grown accustomed to lasers, they’re a part of modern life, from DVD players to cash registers at the grocery store—lasers are everywhere. One thing they all have in common, is that they are based on photon emissions. There are other kinds of similar devices, of course, such as masers, which are based on microwave radiation, but they are not as well known. More lately, research has focused on lasers based on sound, which would emit phonons (lattice vibrations) instead of photons, an idea that’s been thrown around for several years, but hasn’t gotten much traction because the uses for such a laser are still unclear.Back in 2010 a team of researchers succeeded in building a phonon laser (or phaser, as some have taken to calling it) but it relied on the use of an optical laser. In this new effort, the research team has built a phonon laser that is purely mechanical, which the team says, should make it easier to implement in other systems should a reason for doing so be found.Photon lasers work by exciting electrons in a crystal or gas, then allowing them to revert to a more relaxed state. When they do so, a certain wavelength of light is released which is focused using mirrors.To build their phonon laser, the team followed the same basic design—a mechanical oscillator excites some amount of phonons, which are then allowed to revert back to a relaxed state. But the energy is still in the system—it causes the device to vibrate at a desired frequency within a very narrow wavelength, making it a lasing device. The entire laser has been etched onto a single integrated circuit.While researchers still aren’t clear to what purpose such a laser might be put, especially in light of the fact that phonons require a transmission medium to work, that hasn’t stopped them from proceeding. When the photon laser was first developed, no one knew what to do with it either. The researchers suggest that phonon lasers might be used to build a tiny clock, or as part of ultrasound machines or even as a very highly accurate measuring device.last_img read more

Researchers attempt to uncover the origins of waters unusual properties

first_imgThe proposed pressure-temperature (P-T) phase diagram shows that, below a critical point, water is either in the high-density structure or in the low-density structure. However, above the critical point in a funnel-like region, water is constantly fluctuating between these two structures, and these structural fluctuations are what give rise to many of water’s anomalous properties. Credit: Nilsson and Pettersson. Nature Communications. More information: Anders Nilsson and Lars G.M. Pettersson. “The structural origin of anomalous properties of liquid water.” Nature Communications. DOI: 10.1038/ncomms9998 Explore further Outside of the funnel-like region, water stops behaving anomalously and begins behaving more like other liquids. In these regions, water’s structure is homogeneous, existing as only the low-density structure below the funnel-like region and only the high-density structure above the funnel-like region. While the new paper combines many years of data into one cohesive picture, many questions still remain. One unanswered question, for instance, is why does water’s anomalous region occur at the same temperatures and pressures that sustain life? It seems likely that water’s anomalous region served to place constraints on the conditions required for life to exist. A better understanding of this overlap could have implications for understanding life on a fundamental level.Many other questions also require further investigation. The researchers explain that their proposed interpretation is a very simple picture, and it does not tell the exact degree of heterogeneity in water in the anomalous region, nor does it describe the nature of the boundaries between the spatially separated fluctuating regions. Another area of investigation that has challenged researchers is the so-called “no-man’s land” region, which refers to the possibility of liquid water at temperatures below 232 K (-42 °C and -42 °F) but above 150 K (-123 °C, -189 °F). It’s extremely challenging to cool liquid water to these cold temperatures quickly enough so that it can be probed, even for a moment, before it turns to solid ice. In 2014, scientists successfully cooled liquid water to 5 K below no-man’s land and measured its structure using an X-ray laser—the Linac Coherent Light Source at the SLAC National Accelerator Laboratory. Experiments like these are needed to answer the question of whether water can exist in a liquid state in this region, which would help complete the P-T phase diagram.In the future, the researchers plan to investigate how water’s structural fluctuations contribute to other intriguing phenomena.”We will focus on using X-ray lasers to probe the supercooled regime and search for the liquid-liquid transition and second critical point,” Nilsson said. “We are also developing probe dynamics using the femtosecond time resolution of the X-ray lasers, allowing eventually to probe the dynamics of these structural fluctuations. There might be some intricate coupling of time and space on various length and time scales that are still unknown. “We hope that others will also bring other techniques involving time resolved two-dimensional IR spectroscopy, NMR and neutron scattering to further investigate water along these lines. Also further refinement of theoretical approaches to both calculate experimental observables but also to simulate water.” Evidence for solid-liquid critical points of water in carbon nanotubes Journal information: Nature Communications (—In many ways, water behaves very differently than other liquids do, and with important consequences: It’s widely thought that water’s unusual properties were essential for the development of life on Earth. One prime example is the fact that ice floats. Unlike other substances, frozen water is less dense than liquid water, and this anomaly allows fish and other aquatic lifeforms to survive in the water under a frozen layer of protective ice during cold periods. Water also has a high heat capacity, meaning it can absorb and release a large amount of heat while undergoing very little change in temperature. This property helps many living organisms maintain a relatively stable body temperature, and it also provides a pleasant climate in Europe due to the warm Gulf Stream current. © 2016 Citation: Researchers attempt to uncover the origins of water’s unusual properties (2016, January 12) retrieved 18 August 2019 from It’s widely known that water’s anomalous properties are related to its hydrogen bonds, which cause liquid water to arrange itself in a highly ordered way because of the attraction between the hydrogen atoms in one water molecule and the oxygen atoms in adjacent molecules. However, researchers do not completely understand how water’s unique hydrogen-bonded structure leads to its anomalous properties. In a review paper published in Nature Communications, physicists Anders Nilsson and Lars G.M. Pettersson from Stockholm University have pulled together the results from dozens of papers published over the past several years that have investigated water’s molecular structure, often with the help of cutting-edge experimental tools and simulations. In their interpretation of the data, the researchers have proposed a picture of water in which its unique properties arise from its heterogeneous structure.The researchers propose that, in the pressure (P) and temperature (T) region where water exhibits its anomalous behaviors (the funnel-like region in the P-T phase diagram above), water coexists in two different types of structures: a highly ordered, low-density structure with strong hydrogen bonds, and a somewhat smashed, high-density structure with distorted hydrogen bonds. The origins of water’s anomalous properties arise because these two types of structures are constantly fluctuating between one another in this heterogeneous phase, resulting in many small spatially separated regions of different structures.”It is the fluctuations between high-density liquid and low-density liquid that give rise to the anomalous properties,” Nilsson told water’s large heat capacity, for instance. As Nilsson explained, heat capacity is related to entropy fluctuations, and entropy is in turn related to the number of possible ways the available energy can be distributed in the system. Fluctuations between the low- and high-density local structures increase the magnitude of the entropy fluctuations and, consequently, the heat capacity. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. 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New study takes a different approach to showing human activity causing earthquakes

first_img © 2017 Journal information: Science Advances Fracking, extracting natural gas using hydraulic fracturing, and other techniques, have been in the news a lot of late. On the one hand, it has been credited with helping the U.S. become less dependent on foreign oil. But on the other hand, more studies are finding that in addition to harming the environment, the practice appears to be causing small earthquakes. It should be noted that it is not the actual fracking that is believed to cause earthquakes, it is the practice of forcing the dirty water left over from the process back into the ground afterwards that appears to cause the problems—it loosens material around underground faults.There is little doubt that more earthquakes have been occurring in parts of the U.S. since fracking began, but less certain is whether fracking is the cause. The strongest proof to date has been the location of the upswing in small earthquakes around areas where fracking is conducted. In this new effort, the researchers sought to take a more scientific approach to settling the matter—they used the same technology that the oil companies use to find underground deposits of oil and gas—high-resolution seismic reflection imaging. But instead of looking for oil or gas, the researchers looked for deformed faults beneath the ground in the Forth Worth basin. They compared seismic readings in Texas with those from sites in a northern part of Mississippi with a history of small quakes going back to the 1800s, well before fracking began.The researchers report that their readings showed that the most recent natural fault activity beneath the Fort Worth basin was approximately 70 million years ago. That meant that the team was unable to find any natural cause for the recent quakes, leaving fracking as the only possible culprit. Explore further Citation: New study takes a different approach to showing human activity causing earthquakes in Texas (2017, November 27) retrieved 18 August 2019 from More information: Maria Beatrice Magnani et al. Discriminating between natural versus induced seismicity from long-term deformation history of intraplate faults, Science Advances (2017). DOI: 10.1126/sciadv.1701593AbstractTo assess whether recent seismicity is induced by human activity or is of natural origin, we analyze fault displacements on high-resolution seismic reflection profiles for two regions in the central United States (CUS): the Fort Worth Basin (FWB) of Texas and the northern Mississippi embayment (NME). Since 2009, earthquake activity in the CUS has increased markedly, and numerous publications suggest that this increase is primarily due to induced earthquakes caused by deep-well injection of wastewater, both flowback water from hydrofracturing operations and produced water accompanying hydrocarbon production. Alternatively, some argue that these earthquakes are natural and that the seismicity increase is a normal variation that occurs over millions of years. Our analysis shows that within the NME, faults deform both Quaternary alluvium and underlying sediments dating from Paleozoic through Tertiary, with displacement increasing with geologic unit age, documenting a long history of natural activity. In the FWB, a region of ongoing wastewater injection, basement faults show deformation of the Proterozoic and Paleozoic units, but little or no deformation of younger strata. Specifically, vertical displacements in the post-Pennsylvanian formations, if any, are below the resolution (~15 m) of the seismic data, far less than expected had these faults accumulated deformation over millions of years. Our results support the assertion that recent FWB earthquakes are of induced origin; this conclusion is entirely independent of analyses correlating seismicity and wastewater injection practices. To our knowledge, this is the first study to discriminate natural and induced seismicity using classical structural geology analysis techniques.center_img Pennsylvania correlates natural gas fracking with quakes Post-2008 seismicity rate change in the central United States. Since 2009, seismicity has occurred both in areas that were seismically active before 2008 (for example, the Mississippi embayment) and in regions with no pre-2008 historical or instrumental seismicity (for example, the Fort Worth Basin). Credit: Magnani et al., Sci. Adv. 2017;3: e1701593 (—A team of researchers with Southern Methodist University in Texas and the U.S. Geological Survey Earthquake Hazard Program in Virginia has taken a new approach to studying the increase of earthquakes in Texas. In their paper published on the open access site Science Advances, the group suggests their findings indicate that the wastewater injection process is the only possible cause of a recent uptick in earthquakes around the Fort Worth area. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Connecting poles

first_imgThe Polish Institute in New Delhi is presenting the 2nd edition of the KINOTEKA Polish Film Festival with the aim of bringing acclaimed Polish movies to Indian audiences. The festval begins from 19 November to 12 December in Delhi and Mumbai. The Delhi edition will be hosted at the India Habitat Centre and the Alliance Française de Delhi. It celebrates the best of Polish cinema, including award-winning films from Poland’s great auteur and cutting edge, exciting work from a new generation of Polish film-making talent. Also Read – ‘Playing Jojo was emotionally exhausting’‘The Polish Institute is bringing new Polish films from the years 2012-2014 including the Oscar candidate from Poland Ida by Pawel Pawlikowski. We are also celebrating KrzysztofKieslowski’s Decalogue as this year marks the 25th anniversary of the series. ‘The great film maker’s retrospective will be shown at IFFI Goa as well,’ says Anna Tryc-Bromley, Director, Polish Institute, New Delhi.The Festival will kick off in Mumbai on 19 November and draw to a close in Delhi on 12 December. The two-city Festival is also split into two parts: the first, called Polish Cinema Now is focused on contemporary Polish cinema, and features some of the most recent film successes, including Andrzej Jakimowski’s highly-acclaimed Imagine, which opens the Delhi leg of Kinoteka in the presence of the director himself on 2 December, and that of his wife Ewa Jakimowska who worked on the film’s production design. Also Read – Leslie doing new comedy special with NetflixOther films in this section are also highly-rated such as Ida, which has been nominated for next year’s Oscars in the Best Foreign Language Film category . The second part of the Festival is a tribute to arguably Poland’s best known film director – Krzysztof Kieslowski. The Decalogue series, and on the occasion the first four episodes from it will be screened  as part of a Krzysztof Kieslowski Retrospective.Where: India Habitat Centre and Alliance Française de Delhi When : 19 November – 12 Decemberlast_img read more

Craft for the cause

first_imgEmpowerment, a socio-cultural not for profit NGO, aims to preserve art and cultural heritage of India through promotion and revival of arts and crafts presented Colours of Himalayas a showcasing of handmade products of tribal women from flood affected area of Uttarakhand.The chief guest of the event Santosh Kumar Gangwar  Minister of State for Ministry of Textiles (IC)  inaugurated the  exhibition December 12 at Artizen Art Gallery in New Delhi. On display were shawls, stoles, carpets, bamboo products, copper ware products, paintings and photographs depicting Uttarakhand and its crafts. Empowerment also hosted a ramp show where models wearing the traditional outfit of Uttarakhand showcased the dresses. The exhibition remained open till December 14. Also Read – ‘Playing Jojo was emotionally exhausting’All proceeds from the resulting sales of the products will directly go to these women artisans and weavers, motivating and inspiring them to return to normal stream and move towards sustainable development. The exhibition was curated by Sonika Agrawal and Kumar Vikas Saxena, who have closely watched these women going from being totally helpless and dejected to the spirit of wanting to move ahead and create a better living for themselves and their families. They said, “The immersion of the tribal women in crafts have given them a purpose of life and renewed their strength and courage, providing them with hope for the future.”  Also Read – Leslie doing new comedy special with NetflixEmpowerment spreads its message and works through capacity building of women and youth. In June 2013, a cloudburst on the North Indian state of Uttarakhand caused devastating floods and landslides becoming the country’s worst natural disaster. Though relief poured in from various sectors, a sustained effort is required so that people are rehabilitated and empowered through capacity building and work towards sustenance.last_img read more

Court again refuses to allow Daburs Burman to go abroad

first_imgDabur promoter Pradip Burman, whose name has cropped up in the blackmoney list, was on Thursday once again stopped from going abroad by a Delhi court which said there was an apprehension that he could flee.Additional Chief Metropolitan Magistrate (ACMM) Devendra Kumar Sharma, rejected Burman’s application saying no fresh ground is made out after the dismissal of his earlier plea on January 20 and the plea was without any merit.This was the second time in three days that Burman’s plea to go abroad has been rejected by the court. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJIBurman, who had earlier sought permission to travel to Hong Kong to attend his elder brother’s death anniversary, had moved another plea yesterday choosing a new ground that he wanted to attend the 70th birthday of his brother’s wife.During the arguments on Thursday, Income Tax (IT) Department’s standing counsel Brijesh Garg opposed the plea saying India does not have double taxation agreement with Hong Kong, and if the accused does not return, it would be difficult to bring him back.“Moreover, there is apprehension on behalf of the complainant (IT department) that the accused may flee from the jurisdiction of the court to such a jurisdiction from where he cannot be brought back.“This apprehension of the complainant finds force as there is no treaty between India and Hong Kong even for the purposes of taxation and in this regard, document is placed on record on behalf of the complainant,” the court said.last_img read more

Construction of proposed bridge over River Ajay to start soon

first_imgKolkata: The construction of the bridge over river Ajay connecting Kenduli in Birbhum and Shibpur in West Burdwan to initiate soon. According to a senior officer of the state Public Works Department, necessary tasks that is required for commencement of the construction of the bridge has been completed and the agency that will carry out the work takes about three to four months to complete the ground work before initiating the work. Hence, the work is expected to start soon. Also Read – Heavy rain hits traffic, flightsTwo bridges will be constructed across river Ajay. Both the bridges will be of three lanes. One will come up just beside an existing one, which is in a poor condition, connecting Moregram and Panagarh in West Burdwan. The bridge is a part of the National Highway 60. The construction work of the new one has already started and it will come up at a project cost of Rs 163 crore. The other bridge is coming up to connect Kenduli in Birbhum at one end with Shibpur in West Midnapore on the other side of river Ajay. The bridge is coming up at a cost of Rs 130 crore. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedOnce the construction of the bridge is completed, one will need to travel 30 km less to reach Durgapur from Duprajpur. The people of the area will be immensely benefitted and the economy of the place will witness a boom. It may be mentioned that the place is famous for Jaidev Kenduli Mela where lakhs of people visit every year. Chief Minister Mamata Banerjee inaugurates Jaidev Kenduli Mela every year. People visiting the Mela every year will also be benefitted with the construction of the bridge as it would take lesser time for them to reach the Mela premises. After coming to power, the Mamata Banerjee government has taken up several projects to develop the infrastructure to ensure better road connectivity in the state and the construction of the bridge will be helpful to thousands of people as they no more have to travel extra kilometres to reach Durgapur Expressway. In the absence of the bridge, one from Dubrajpur needs to travel through National Highway 2B to reach Durgapur. But with the construction, one can take a turn from Jaidev More and will straightway reach Durgapur Expressway after crossing the bridge. Mamata Banerjee government has taken up several such projects and the state has witnessed a massive development in road connectivity in the past six and a half years.last_img read more