Celebrating 60 years of atomic timekeeping

In an attempt to move timekeeping away from traditional definitions expressed in terms of the period of the Earth’s rotation, physicist Louis Essen spent the early 1950s developing his pioneering atomic clock at the National Physical Laboratory (NPL). On 3 June 1955, Essen started to control the UK radio time signals using atomic units of time derived from the atomic clock, effectively marking what Essen called “the death of the astronomical second and the birth of atomic time.”

Essen showed that atoms, which have a set of discrete energy levels, could provide a much more stable reference time interval. By using microwaves to excite electrons from one energy level to another within atoms of caesium, Essen was able to stabilise the microwaves at a precise and reproducible frequency. Much like a grandfather clock depends on the swinging of a pendulum, Essen’s prototype atomic clock relied on this underlying frequency to mark the passing of time.

Although different elements have since been used in other types of atomic clock, the caesium clock has remained the fundamental standard of time and frequency. Since 1967, the SI second has been defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.

Such high levels of accuracy may seem unnecessary in everyday life, but in reality the clocks in train stations, video recorders and mobile phones all use atomic time to ensure they are perfectly synchronised. When it comes to more specialised functions, atomic time is also necessary for banking, controlling air traffic, maintaining the Internet, synchronising the distribution of electricity and the Global Positioning System (GPS) for navigation. Without the invention of atomic timekeeping, none of these things would be possible.

Since Essen’s pioneering work, the accuracy of atomic clocks has steadily improved by a factor of 10 or so every decade. The major improvement in the accuracy of caesium clocks has been achieved through the use of laser-cooled caesium atoms in complex laboratory clocks known as caesium fountains. NPL’s current primary clock, the caesium fountain NPL-CsF2, contributes to the generation of the international time scale UTC and is the reference for the UK’s national time scale UTC(NPL). It is over 300,000 times more precise than Essen’s original clock, which is now housed in the Science Museum in London.

“It is hard to overstate the significance of Louis Essen’s contribution,” said Professor Patrick Gill at NPL. “Although other researchers were experimenting with atomic timekeeping at roughly the same time, it was Essen who first developed the working prototype that has come to define the digital age.”

As the UK’s home of precise timing, NPL is continuing to develop ways to measure time ever more accurately and improve the performance of its atomic clocks. The next generation of these devices – optical clocks based on laser-cooled trapped ions or neutral atoms – should achieve accuracies equivalent to losing or gaining no more than one second in the lifetime of the universe. Efforts to develop accurate atomic clocks which can be used outside of the lab to widen their applications are also under way.

Dr Leon Lobo, Strategic Business Development Manager for Time & Frequency at NPL, said: “As well as continuing to improve accuracy, we are also looking to miniaturise atomic clocks. By making accurate atomic clocks portable, we could unlock the benefits of precise timing for countless applications. In the near future, we could use miniature atomic clocks to send unhackable communications, help timestamp high frequency trades, improve deep space navigation, and eventually integrate them into smartphones, increasing data transfer rates in communications networks.”

Find out more about the history of atomic timekeeping at NPL

Find out about NPL’s current Time & Frequency work

Contact: Leon Lobo

Link original da postagem: http://www.npl.co.uk/news/celebrating-60-years-of-atomic-timekeeping?utm_source=measurementnews&utm_medium=email&utm_campaign=june2015

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Proposta que muda política nacional de CT&I chega à Presidência da Câmara

Após quatro anos de negociações com a área científica, o governo e o setor empresarial, a proposta que altera a política nacional de ciência, tecnologia e inovação foi entregue ontem, em um ato simbólico, ao presidente da Câmara, Eduardo Cunha, para ser recolocada na pauta do Plenário.

Trata-se do substitutivo do deputado Sibá Machado (PT-AC), relator da matéria, ao Projeto de Lei (PL) 2177/2011. A expectativa é de que o texto seja colocado na pauta de votação na próxima semana. Conhecida como Marco Legal de CT&I, a proposta atende algumas recomendações da comunidade científica e do setor empresarial.

A entrega simbólica do texto aconteceu depois do seminário realizado na manhã de quinta-feira, 18, na Frente Parlamentar de Ciência, Tecnologia, Pesquisa e Inovação, da Câmara, que reuniu a comunidade científica, deputados e órgãos do governo para discutir o novo Código Nacional de CT&I.

Participaram da mesa da cerimônia a presidente da Sociedade Brasileira para o Progresso da Ciência (SBPC), Helena Nader, o presidente do Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Hernan Chaimovich, e o presidente do Conselho Nacional das Fundações Estaduais de Amparo à Pesquisa (Confap), Sergio Gargioni, dentre outras instituições.

O documento foi entregue a Cunha pelo presidente da Frente Parlamentar, deputado Izalci (PSDB-DF), Sibá Machado, juntamente com os participantes do seminário.

O deputado Izalci espera que a matéria seja colocada em votação na próxima semana e prometeu fazer um apelo aos líderes partidários. “Vou conversar com os líderes, na reunião de líderes, para priorizar isso, até porque o projeto já está na pauta”, disse.

Tripla hélice

Sibá Machado fez uma avaliação em sua proposta e a chamou de “tripla hélice” por estreitar as relações entre empresa, governo e universidade e dar um novo rumo à ciência em prol do desenvolvimento do País.  Segundo ele, o PL melhora todo o sistema de CT&I nacional.

“O PL estimula o desenvolvimento científico, a pesquisa, capacitação científica e vai ter que dialogar diretamente com a emenda que apresentamos, que será uma espécie de lei complementar da Emenda Complementar 85”, acrescentou Sibá.

O substitutivo ao PL 2.177/2011 altera, por exemplo, a Lei nº 10.973, de 2 de dezembro de 2004, estabelecendo  medidas de incentivo à inovação e à pesquisa científica e tecnológica no ambiente produtivo. Ou seja, promove atividades científicas e tecnológicas como estratégicas para o desenvolvimento econômico e social; e cooperação e interação entre os entes públicos, o setor público e o privado e entre empresas.

Sibá Machado reconheceu os esforços da SBPC que vem batalhando por um novo Marco Legal de CT&I há quatro anos, dentre outras instituições.

A presidente da SBPC comemorou o avanço na tramitação da proposta e lembrou que essa é uma batalha que vem desde a gestão de Marco Antônio Raupp, que foi ministro da pasta de CT&I. Segundo recorda, a SBCP fez a primeira reunião com todas as sociedades científicas, na unidade da Maria Antonia (região central de São Paulo), em 2010, ainda com o então presidente Luiz Inácio Lula da Silva.

“Ali foi colocado que precisávamos de uma legislação pró-ciência, porque a atual é anti-ciência”, disse Helena.

Desenvolvimento nacional

No entendimento da presidente da SBPC, o Brasil poderá contar com uma ciência de qualidade capaz de produzir tecnologia e inovação. Para ela, isso hoje é inviável, diante da insegurança jurídica que existe no ambiente de negócios, desestimulando os investimentos empresariais internamente.

Por sua vez, o presidente do CNPq, Chaimovich disse que o texto coloca de “forma objetiva” os avanços da Emenda Constitucional nº 85. “O mais importante nesse Projeto de Lei é que avança a segurança jurídica que permite que a ciência e tecnologia, de fato, contribuam para o avanço social, econômico e intelectual do País”, analisou.

O presidente do Confap, Sergio Gargioni, também elogiou a proposta da nova legislação, ainda que reconheça a necessidade de ajustes em alguns pontos.

Existem pontos no texto que ainda não tiveram consenso com partes do governo. Um deles é o que permite transferência de recursos da União para ICTs (instituições científicas, de tecnologia e de inovação) – entre as esferas estadual, distrital ou municipal – em projetos de CT&I sem restrições em razão de inadimplência de quaisquer outros órgãos ou instâncias.

Outro ponto não consensual é o que assegura remuneração ao pesquisador público quando fizer colaboração com outra ICT ou empresas.

(Viviane Monteiro/ Jornal da Ciência)

Link original da postagem: http://www.jornaldaciencia.org.br/edicoes/?url=http://jcnoticias.jornaldaciencia.org.br/1-proposta-que-muda-politica-nacional-de-cti-chega-a-presidencia-da-camara/

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Physicists Are Philosophers, Too

In his final essay the late physicist Victor Stenger argues for the validity of philosophy in the context of modern theoretical physics.

In April 2012 theoretical physicist, cosmologist and best-selling author Lawrence Krauss was pressed hard in an interview with Ross Andersen for The Atlantic titled “Has Physics Made Philosophy and Religion Obsolete?” Krauss’s response to this question dismayed philosophers because he remarked, “philosophy used to be a field that had content,” to which he later added, “Philosophy is a field that, unfortunately, reminds me of that old Woody Allen joke, “those that can’t do, teach, and those that can’t teach, teach gym.” And the worst part of philosophy is the philosophy of science; the only people, as far as I can tell, that read work by philosophers of science are other philosophers of science. It has no impact on physics whatsoever, and I doubt that other philosophers read it because it’s fairly technical. And so it’s really hard to understand what justifies it. And so I’d say that this tension occurs because people in philosophy feel threatened—and they have every right to feel threatened, because science progresses and philosophy doesn’t.”

Later that year Krauss had a friendly discussion with philosopher Julian Baggini inThe Observer, an online magazine from The Guardian. Although showing great respect for science and agreeing with Krauss and most other physicists and cosmologists that there isn’t “more stuff in the universe than the stuff of physical science,” Baggini complained that Krauss seems to share “some of science’s imperialist ambitions.” Baggini voices the common opinion that “there are some issues of human existence that just aren’t scientific. I cannot see how mere facts could ever settle the issue of what is morally right or wrong, for example.”

Krauss does not see it quite that way. Rather he distinguishes between “questions that are answerable and those that are not,” and the answerable ones mostly fall into the “domain of empirical knowledge, aka science.” As for moral questions, Krauss claims that they only be answered by “reason…based on empirical evidence.” Baggini cannot see how any “factual discovery could ever settle a question of right and wrong.”

Nevertheless, Krauss expresses sympathy with Baggini’s position, saying, “I do think philosophical discussion can inform decision-making in many important ways—by allowing reflections on facts, but that ultimately the only source of facts is via empirical exploration.” Noted philosophers were upset with The Atlantic interview, including Daniel Dennett of Tufts University who wrote to Krauss. As a result, Krauss penned amore careful explication of his position that was published in Scientific American in 2014 under the title “The Consolation of Philosophy.” There he was more generous to philosophy’s contribution to the enrichment of his own thinking, although he conceded little of his basic position:

“As a practicing physicist…I, and most of the colleagues with whom I have discussed this matter, have found that philosophical speculations about physics and the nature of science are not particularly useful, and have had little or no impact upon progress in my field. Even in several areas associated with what one can rightfully call the philosophy of science I have found the reflections of physicists to be more useful.” Krauss is not alone among physicists in his disdain for philosophy. In September 2010 physicists Stephen Hawking and Leonard Mlodinow published a shot heard round the world—and not just the academic world. On the first page of their book, The Grand Design, they wrote: “Philosophy is dead” because “philosophers have not kept up with modern developments in science, particularly physics. Scientists have become the bearers of the torch of discovery in our quest for knowledge.”

The questions that philosophy is no longer capable of handling (if it ever was) include: How does the universe behave? What is the nature of reality? Where did all this come from? Did the universe need a creator? According to Hawking and Mlodinow, only scientists—not philosophers—can provide the answers.

Famous astrophysicist and science popularizer Neil deGrasse Tyson has joined the debate. In an interview on the Nerdist podcast in May 2014 Tyson remarked, “My concern here is that the philosophers believe they are actually asking deep questions about nature. And to the scientist it’s, ‘What are you doing? Why are you concerning yourself with the meaning of meaning?’” His overall message was clear: science moves on; philosophy stays mired, useless and effectively dead.

Needless to say, Tyson also has been heavily criticized for his views. His position can be greatly clarified by viewing the video of his appearance in a forum at Howard University in 2010, where he was on the stage with biologist Richard Dawkins. Tyson’s argument is straightforward and is the same as expressed by Krauss: Philosophers from the time of Plato and Aristotle have claimed that knowledge about the world can be obtained by pure thought alone. As Tyson explained, such knowledge cannot be obtained by someone sitting back in an armchair. It can only be gained by observation and experiment. Richard Feynman had once expressed a similar opinion about “armchair philosophers.” Dawkins agreed with Tyson, pointing out that natural selection was discovered by two naturalists, Charles Darwin and Alfred Russel Wallace, who worked in the field gathering data.

What we are seeing here is not a recent phenomenon. In his 1992 book Dreams of a Final Theory, Nobel laureate Steven Weinberg has a whole chapter entitled “Against Philosophy.” Referring to the famous observation of Nobel laureate physicist Eugene Wigner about “the unreasonable effectiveness of mathematics,” Weinberg puzzles about “the unreasonable ineffectiveness of philosophy.”

Weinberg does not dismiss all of philosophy, just the philosophy of science, noting that its arcane discussions interest few scientists. He points out the problems with the philosophy of positivism, although he agrees that it played a role in the early development of both relativity and quantum mechanics. He argues that positivism did more harm than good, however, writing, “The positivist concentration on observables like particle positions and momenta has stood in the way of a ‘realist’ interpretation of quantum mechanics, in which the wave function is the representative of physical reality.”

Perhaps the most influential positivist was late 19th-century philosopher and physicist Ernst Mach, who refused to accept the atomic model of matter because he could not see atoms. Today we can see atoms with a scanning tunneling microscope but our models still contain unseen objects such as quarks. Philosophers as well as physicists no longer take positivism seriously, and so it has no remaining influence on physics, good or bad.

Nevertheless, most physicists would agree with Krauss and Tyson that observation is the only reliable source of knowledge about the natural world. Some, but not all, incline toward instrumentalism, in which theories are merely conceptual tools for classifying, systematizing and predicting observational statements. Those conceptual tools may include nonobservable objects such as quarks.

Until very recently in history no distinction was made between physics and natural philosophy. Thales of Miletus (circa 624–546 B.C.) is generally regarded as the first physicist as well as the first philosopher of the Western tradition. He sought natural explanations for phenomena that made no reference to my thology. For example, he explained earthquakes to be the result of Earth resting on water and being rocked by waves. He reasoned this from observation, not pure thought: Land is surrounded by water and boats on water are seen to rock. Although Thales’ explanation for earthquakes was not correct, it was still an improvement over the mythology that they are caused by the god Poseidon striking the ground with his trident.

Thales is famous for predicting an eclipse of the sun that modern astronomers calculate occurred over Asia Minor on May 28, 585 B.C. Most historians today, however, doubt the truth of this tale. Thales’ most significant contribution was to propose that all material substances are composed of a single elementary constituent—namely, water. Whereas he was (not unreasonably) wrong about water being elementary, Thales’ proposal represents the first recorded attempt, at least in the West, to explain the nature of matter without the invocation of invisible spirits.

Thales and other Ionian philosophers who followed espoused a view of reality now called material monism in which everything is matter and nothing else. Today this remains the prevailing view of physicists, who find no need to introduce supernatural elements into their models, which successfully describe all their observations to date.

The rift to which Tyson was referring formed when physics and natural philosophy began to diverge into separate disciplines in the 17th century after Galileo and Newton introduced the principles that describe the motion of bodies. Newton was able to derive from first principles the laws of planetary motion that had been discovered earlier by Kepler. The successful prediction of the return of Halley’s Comet in 1759 demonstrated the great power of the new science for all to see.

The success of Newtonian physics opened up the prospect for a philosophical stance that became known as the clockwork universe, or alternatively, the Newtonian world machine. According to this scheme, the laws of mechanics determine everything that happens in the material world. In particular, there is no place for a god who plays an active role in the universe. As shown by the French mathematician, astronomer and physicist Pierre-Simon Laplace, Newton’s laws were in themselves sufficient to explain the movement of the planets throughout previous history. This led him to propose a radical notion that Newton had rejected: Nothing besides physics is needed to understand the physical universe.

Whereas the clockwork universe has been invalidated by the Heisenberg uncertainty principle of quantum mechanics, quantum mechanics remains devilishly hard to interpret philosophically. Rather than say physics “understands” the universe, it is more accurate to say that the models of physics remain sufficient to describe the material world as we observe it to be with our eyes and instruments.

In the early part of the 20th century almost all the famous physicists of the era—Albert Einstein, Niels Bohr, Erwin Schrödinger, Werner Heisenberg, Max Born, among others—considered the philosophical ramifications of their revolutionary discoveries in relativity and quantum mechanics. After World War II, however, the new generation of prominent figures in physics—Richard Feynman, Murray Gell-Mann, Steven Weinberg, Sheldon Glashow and others—found such musings unproductive, and most physicists (there were exceptions in both eras) followed their lead. But the new generation still went ahead and adopted philosophical doctrines, or at least spoke in philosophical terms, without admitting it to themselves.

For example, when Weinberg promotes a “realist” interpretation of quantum mechanics, in which “the wave function is the representative of physical reality,” he is implying that the artifacts theorists include in their models, such as quantum fields, are the ultimate ingredients of reality. In a 2012 Scientific American article theoretical physicist David Tong goes even further than Weinberg in arguing that the particles we actually observe in experiments are illusions and those physicists who say they are fundamental are disingenuous:

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“Physicists routinely teach that the building blocks of nature are discrete particles such as the electron or quark. That is a lie. The building blocks of our theories are not particles but fields: continuous, fluidlike objects spread throughout space.”

This view is explicitly philosophical, and accepting it uncritically makes for bad philosophical thinking. Weinberg and Tong, in fact, are expressing a platonic view of reality commonly held by many theoretical physicists and mathematicians. They are taking their equations and model as existing on one-to-one correspondence with the ultimate nature of reality.

In the reputable online Stanford Encyclopedia of Philosophy, Mark Balaguer defines platonism as follows:

“Platonism is the view that there exist [in ultimate reality] such things as abstract objects—where an abstract object is an object that does not exist in space or time and which is therefore entirely nonphysical and nonmental. Platonism in this sense is a contemporary view. It is obviously related to the views of Plato in important ways but it is not entirely clear that Plato endorsed this view as it is defined here. In order to remain neutral on this question, the term ‘platonism’ is spelled with a lower-case ‘p.’”

We will use platonism with a lower-case “p” here to refer to the belief that the objects within the models of theoretical physics constitute elements of reality, but these models are not based on pure thought, which is Platonism with a capital “P,” but fashioned to describe and predict observations. Many physicists have uncritically adopted platonic realism as their personal interpretation of the meaning of physics. This not inconsequential because it associates a reality that lies beyond the senses with the cognitive tools humans use to describe observations.

In order to test their models all physicists assume that the elements of these models correspond in some way to reality. But those models are compared with the data that flow from particle detectors on the floors of accelerator labs or at the foci of telescopes (photons are particles, too). It is data—not theory—that decides if a particular model corresponds in some way to reality. If the model fails to fit the data, then it certainly has no connection with reality. If it fits the data, then it likely has some connection. But what is that connection? Models are squiggles on the whiteboards in the theory section of the physics building.

Those squiggles are easily erased; the data can’t be. In his Scientific American article Krauss reveals traces of platonic thinking in his personal philosophy of physics, writing:

“There is a class of philosophers, some theologically inspired, who object to the very fact that scientists might presume to address any version of this fundamental ontological issue. Recently one review of my book [A Universe from Nothing] by such a philosopher…. This author claimed with apparent authority (surprising because the author apparently has some background in physics) something that is simply wrong:

that the laws of physics can never dynamically determine which particles and fields exist and whether space itself exists or more generally what the nature of existence might be. But that is precisely what is possible in the context of modern quantum field theory in curved spacetime.”

The direct, platonic, correspondence of physical theories to the nature of reality, as Weinberg, Tong and possibly Krauss have done, is fraught with problems:

First, theories are notoriously temporary. We can never know if quantum field theory will not someday be replaced with another more powerful model that makes no mention of fields (or particles, for that matter). Second, as with all physical theories, quantum field theory is a model—a human contrivance. We test our models to find out if they work; but we can never be sure, even for highly predictive models like quantum electrodynamics, to what degree they correspond to “reality.” To claim they do is metaphysics. If there were an empirical way to determine ultimate reality, it would be physics, not metaphysics; but it seems there isn’t.

In the instrumentalist view we have no way of knowing what constitutes the elements of ultimate reality. In that view reality just constrains what we observe; it need not exist in one-to-one correspondence with the mathematical models theorists invent to describe those observations. Furthermore, it doesn’t matter. All these models have to do is describe observations, and they don’t need metaphysics to do that. The explanatory salience of our models may be the core of the romance of science but it plays second chair to its descriptive and predictive capacity. Quantum mechanics is a prime example of this because of its unambiguous usefulness despite lacking an agreed-on philosophical interpretation.

Thus, those who hold to a platonic view of reality are being disingenuous when they disparage philosophy. They are adopting the doctrine of one of the most influential philosophers of all time. That makes them philosophers, too. Now, not all physicists who criticize philosophers are full-fledged platonists, although many skirt close to it when they talk about the mathematical elements of their models and the laws they invent as if they are built into the structure of the universe. Indeed, the objections of Weinberg, Hawking, Mlodinow, Krauss, and Tyson are better addressed to metaphysics and fail to show sufficient appreciation, in our view, for the vital contributions to human thought that persist in fields like ethics, aesthetics, politics and, perhaps most important, epistemology. Krauss pays these important topics some lip service, but not very enthusiastically.

Of course, Hawking and Mlodinow write mostly with cosmological concerns in mind—and where metaphysical attempts to grapple with the question of ultimate origins trespass on them, they are absolutely correct. Metaphysics and its proto-cosmological speculations, construed as philosophy, were in medieval times considered the handmaiden of theology. Hawking and Mlodinow are saying that metaphysicians who want to deal with cosmological issues are not scientifically savvy enough to contribute usefully. For cosmological purposes, armchair metaphysics is dead, supplanted by the more informed philosophy of physics, and few but theologians would disagree.

Krauss leveled his most scathing criticisms at the philosophy of science, and we suggest that it would have been more constructive had he targeted certain aspects of metaphysics. Andersen, for The Atlantic, interviewed him on whether physics has made philosophy and religion obsolete. And although it hasn’t done so for philosophy, it has for cosmological metaphysics (and the religious claims that depend on it, such as the defunct Kalām cosmological argument begging the necessity of a creator). Surely Krauss had metaphysical attempts to speculate about the universe at least partially in mind, given that the interview addressed his book on cosmology.

Whatever may be the branches of philosophy that deserve the esteem of academics and the public, metaphysics is not among them. The problem is straightforward. Metaphysics professes to be able to hook itself to reality—to legitimately describe reality—but there’s no way to know if it does.

So, although the prominent physicists we have mentioned, and the others who inhabit the same camp, are right to disparage cosmological metaphysics, we feel they are dead wrong if they think they have completely divorced themselves from philosophy. First, as already emphasized, those who promote the reality of the mathematical objects of their models are dabbling in platonic metaphysics whether they know it or not. Second, those who have not adopted platonism outright still apply epistemological thinking in their pronouncements when they assert that observation is our only source of knowledge.

Hawking and Mlodinow clearly reject platonism when they say, “There is no picture- or theory-independent concept of reality.” Instead, they endorse a philosophical doctrine they call model-dependent realism, which is “the idea that a physical theory or world picture is a model (generally of a mathematical nature) and a set of rules that connect the elements of the model to observations.” But they make it clear that “it is pointless to ask whether a model is real, only whether it agrees with observations.”

We are not sure how model-dependent realism differs from instrumentalism. In both cases physicists concern themselves only with observations and, although they do not deny that they are the consequence of some ultimate reality, they do not insist that the models describing those observations correspond exactly to that reality. In any case, Hawking and Mlodinow are acting as philosophers—epistemologists at the minimum—by discussing what we can know about ultimate reality, even if their answer is “nothing.”

All of the prominent critics of philosophy whose views we have discussed think very deeply about the source of human knowledge. That is, they are all epistemologists. The best they can say is they know more about science than (most) professional philosophers and rely on observation and experiment rather than pure thought—not that they aren’t philosophizing. Certainly, then, philosophy is not dead. That designation is more aptly applied to pure-thought variants like those that comprise cosmological metaphysics.

Thanks to Don McGee, Brent Meeker, Chris Savage, Jim Wyman and Bob

Zannelli for their helpful comments.

Victor J. Stenger (1935–2014) was emeritus professor of physics at the University of Hawaii and adjunct professor of philosophy at the University of Colorado. He is author of The New York Times bestseller, God:The Failed Hypothesis: How Science Shows That God Does Not Exist. His latest book is God and the Multiverse: Humanity’s Expanding View of the Cosmos.

James A. Lindsay has a PhD in mathematics and is author of God Doesn’t; We Do: Only Humans Can Solve Human Challenges and Dot, Dot, Dot: Infinity Plus God Equals Folly.

Peter Boghossian is an assistant professor of philosophy at Portland State University and an affiliate faculty member at Oregon Health & Science University in the Division of General Internal Medicine. He is author of the bestseller, A Manual for Creating Atheists.

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Palestra: Por que falar de Inovação?

Palestrante: Anne Marie Maculan

Data: 20 de maio de 2015 (quarta-feira)

Horário: 14 h

Local: Sala de aulas do PPGCI-IBICT/UFRJ (Rua Lauro Muller, 455 – 4. andar – Botafogo – RJ/RJ)

Palestrante

Anne Marie Delaunay Maculan tem doutorado em Sócio-Economia pela Université du Quebec à Montreal e mestrado em Ciência Política pelo IUPERJ  (1989). É professora do Programa de Engenharia de Produção da COPPE/UFRJ. Foi coordenadora do Programa de Engenharia de produção da COPPE e da Área de Gestão da Inovação. É Coordenadora do Pro-PME – Centro de Pesquisa e Projeto para o Desenvolvimento Gerencial e Tecnológico das micro, pequenas e médias empresas. Publicou diversos artigos sobre o tema da Política Brasileira de Ciência e Tecnologia. CV: http://lattes.cnpq.br/1721596116332386.

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Frederico furioso: saúde & doença em Nietzsche

nie

Partindo da discussão mais recente sobre as hipóteses diagnósticas referentes à enfermidade que levou a que Nietzsche, aos 44 anos, interrompesse sua escrita filosófica, este simpósio busca rever o entendimento tanto de sua própria doença quanto da questão saúde-doença em sua obra. Tentamos reunir contribuições relacionadas com a saúde e adoença na vida, obra e crepúsculo de Nietzsche. Trata-se de um evento interdisciplinar que reúne pesquisadores e instituições distintas do Rio de Janeiro (integrantes do GT Nietzsche-Anpof, GT Schöpenhauer e grupos de pesquisa: Filosofia POP, Nietzsche-Gambiarra, etc.).

As apresentações percorrem 3 aspectos principais que correspondem às mesas-redondas. Inicialmente, empreende-se uma revisão do debate sobre o diagnóstico da enfermidade que acometeu Nietzsche. Da sífilis terciária (ou paralisia geral progressiva) até a rediscussão diagnóstica que postula um tumor cerebral (meningioma retro-orbital), em especial nos trabalhos de Sax e de Owen; uma mitocondriopatia (MELAS); demência fronto-temporal (Doença de Pick); ou uma leucodistrofia como CADASIL – desdobra-se um repertório de hipóteses recentemente publicadas em periódicos tão díspares quanto Nietzsche Studien (34\2013) e Neurosurgery (61\2007). Neste nexo, na segunda mesa, cabe colocar em questão a patografia e a experiência de adoecimento; – incluindo suas ressonâncias fenomenológicas e existenciais. A loucura de Nietzsche foi progressivamente incluída em sua obra. Coube especialmente ao século XX disputar sobre o paralelismo psicofísico e as relações entre biografia, história e experiência-limite. A psicanálise seria mais uma versão deste esforço de articulação entre biografia e trama conceitual. Nosso filósofo valetudinário encontra-se exatamente nesta encruzilhada. Na terceira mesa, serão discutidos aspectos da filosofia de Nietzsche que se articulam especialmente com as noções de saúde e doença em seu pensamento mais tardio. A figura do médico da Cultura, assim como o diagnóstico do niilismo, emergem junto à grande Saúde, ao valor do sofrimento e ao estatuto da dor para a reflexão filosófica.

O evento aberto e gratuito. Há limite de lugares e a inscrição prévia é recomendada.

05.05.2015

Local:

Instituto de Medicina Social, Anfiteatro

Universidade do Estado do Rio de Janeiro (UERJ), Maracanã

13h

Abertura

Mesa 1:Diagnósticos atuais da enfermidade

Charles André (UFRJ)

André Rangel Rios (UERJ-IMS)

Rossano Cabral (UERJ-IMS)

14.30h

Mesa 2: Saúde, doença e patografia

José Nicolau Julião (UFRRJ)

Rogério Henriques (UFS–NPPS)

Carlos Estellita-Lins (FIOCRUZ-ICICT)

Luciano Monteiro (FIOCRUZ-COC)

16h

Mesa 3: Cultura, sofrimento e dor

Charles Feitosa (UNIRIO)

Arlinda Moreno (FIOCRUZ-ENSP)

José Thomaz Brum (PUC–RJ)

Rosa Maria Dias (UERJ-PPGFIL)

17.30h

Filmografia com Nietzsche:

Bressane, Syberberg, gambáfugiu

Rouch, Faustón, Porta dos Fundos

Publicado em Divulgação de eventos | Deixe um comentário

Nasce a evolução biológica

POR SALVADOR NOGUEIRA

02/02/15

Mais um dos mistérios que cercam a origem da vida parece ter sido decifrado por um quarteto de cientistas na Alemanha. Eles basicamente descobriram como a evolução pode ter recebido o pontapé inicial da natureza, sem nenhuma ajuda externa.

Talvez surpreenda, sobretudo para aqueles que se apegam a expressões “curinga” como “complexidade irredutível” para se esquivar do problema científico do surgimento da vida, o fato de a solução encontrada pelos pesquisadores — e testada em laboratório — ser de uma simplicidade franciscana.

Comece com microporos numa pedra aquecida, imersa em água. Nada diferente do que já se esperaria encontrar em rochas vulcânicas submersas nos oceanos da Terra, quatro bilhões de anos atrás. O único fator importante é que exista um gradiente de temperatura dentro do microporo — ou seja, que ele seja mais quente numa ponta e mais frio noutra. Algo que já aconteceria mesmo, naturalmente. Aí a “mágica” já está feita.

Os microporos assumem praticamente a função de protocélulas, promovendo a replicação de moléculas portadoras de informação genética, como RNA ou DNA. Com um detalhe adicional: o sistema favorece a replicação de moléculas cada vez mais longas, capazes de armazenar quantidade crescente de informações genéticas. Isso resolve um dos principais dilemas apresentados pelos estudos sobre a origem da vida: como isso pode ter acontecido se, ao serem deixadas ao sabor do mar aberto, as moléculas de DNA e RNA nunca cresceriam para ter sequências maiores, simplesmente porque é mais fácil replicar as moléculas curtas do que as compridas? O resultado mais esperado disso seria uma “seleção natural às avessas”, empurrando sempre na direção da redução da complexidade. A vida nunca apareceria desse jeito. Eis o problema.

Contudo, o esforço de Dieter Braun e seus colegas da Ludwig-Maximilians-Universität, em Munique, vira esse jogo espetacularmente. Como? A descrição completa saiu em artigo publicado na semana passada na revista “Nature Chemistry”. O trabalho mostra que o gradiente de temperatura, combinado a um processo chamado de convecção laminar, promove a entrada e saída de material dos poros e também encoraja o acúmulo e a multiplicação de DNA longo, desprezando as moléculas mais curtas. “Moléculas de 75 nucleotídeos sobrevivem, enquanto moléculas com a metade desse tamanho morrem, o que inverte o dilema da sobrevivência do mais curto”, escrevem os autores do trabalho.

Um sistema que empurra naturalmente as moléculas de DNA e RNA a ficarem maiores é a rota certeira para o surgimento da vida como a conhecemos. Afinal, quanto mais compridas as moléculas, mais sequências de letrinhas químicas (os chamados nucleotídeos) cabem nelas. Em suma, cabe mais informação genética, com preservação natural daquelas que, pelas mutações aleatórias que contêm, se replicam com mais facilidade e eficiência. Imagine esse processo avançando por muito, muito tempo, até que uma molécula tropece numa receita para produzir uma camada protetora ao seu redor. No interior dessa cápsula, a molécula genética complexa poderia finalmente deixar o microporo e ganhar o oceano, sem correr o risco de ser literalmente “diluída”. O resto, como dizem por aí, é história.

Um dos aspectos elegantes do DNA é que ele não tem comprimento definido. Quanto maior, mais informação genética cabe nele.

DESAFIOS PELA FRENTE
Por que esse trabalho não está sendo celebrado como a solução definitiva da origem da vida? Bem, porque ele de fato não é exatamente isso. Ele mostra o que pode ter sido a origem dos processos evolutivos, ainda puramente químicos, que antecederam as primeiras formas de vida. Mas faltam aí dois passos cruciais iniciais que antecedem essa etapa. Como se produzem as primeiras moléculas capazes de portar informação genética (RNA e DNA) e como elas primeiro “aprendem” a promover sua própria replicação? (No experimento, a replicação é promovida por uma proteína de origem biológica, que obviamente estava ausente na origem da vida.)

Essas são perguntas que ainda seguem sem solução. A síntese de RNA e DNA em um ambiente úmido permanece como um desafio porque a criação da molécula exige muitos passos químicos. Até aí, nada demais. O problema é que eles costumam ser perturbados pela água antes que cheguem ao seu desejado desfecho. A água desmancha os compostos antes que eles virem RNA ou DNA.

Alguns pesquisadores buscam chegar lá trabalhando em ambientes desérticos (talvez até em outros planetas). Outros procuram soluções ainda oceânicas, mostrando que reações hoje típicas de metabolismo biológico (que incluem as que são capazes de sintetizar coisas como RNA ou DNA) poderiam ser impulsionadas a partir de química mais simples. Se você seguir os links acima, verá que eles estão bem perto, mas ainda não chegaram exatamente lá.

Uma vez que se produzem as moléculas portadoras de informação, sobretudo no caso do RNA, a auto-replicação já é um problema mais bem encaminhado. Sabemos que o RNA é uma molécula versátil, que pode não só codificar informação como promover sua própria cópia, sem a necessidade de proteínas adicionais. Ele seria o ponto de partida para a evolução biológica, como a entendemos hoje.

No frigir dos ovos, o que os resultados já sugerem é que as barreiras remanescentes não são intransponíveis. Pouco a pouco, cada um dos passos envolvidos na origem da vida é recriado em laboratório, conforme as técnicas e a compreensão dos problemas evoluem. E tudo leva a crer que nenhuma condição extraordinária foi necessária para a aparição de formas de vida. Muito pelo contrário. O que os experimentos mostram é que tudo pode ter sido bem simples. Uma pequena variação de temperatura, a presença de ferro diluído no oceano e outras coisas assim, nada complicadas ou incomuns. O único requerimento realmente crítico para cobrir todas as etapas do processo sem ajuda artificial é o tempo — alguns milhões de anos, para ser preciso. Por isso não devemos esperar que os pesquisadores consigam, num único experimento, partir de química simples e terminar com um ser vivo. Mas eles já conseguem reencenar as diversas etapas cruciais separadamente. Falta muito pouco para entendermos a coisa toda. Estamos quase lá.

Link original da postagem: http://mensageirosideral.blogfolha.uol.com.br/2015/02/02/nasce-a-evolucao-biologica/

Publicado em Artigos sugeridos | Deixe um comentário

Livro com participação de Verusca Moss Simões dos Reis, com o capítulo

“John Ziman: físico e epistemólogo em uma ‘ciência pós-acadêmica’”

capa_8_113Sociologia da Ciência: contribuições ao campo CTS

Maria Cristina Piumbato Innocentini Hayashi, Camila Carneiro Dias Rigolin e Maria Teresa Miceli Kerbauy (orgs.)

Adquira o livro em

http://www.grupoatomoealinea.com.br/sociologia-da-ciencia-contribuicoes-ao-campo-cts.html

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