Cryonics is a technique for freezing dead bodies at very low temperatures in the hope they will be revived at some time in the future when medical technology becomes available. At present, there are no known revival methods; however, the role of innovation in medical practice leads certain individuals to hypothesize that death will be reversible in the future. While cryonics might resonate with certain questionable contemporary Western cultural themes of death denial and neoliberalism its uptake remains minuscule. Several (...) reasons may be pertinent. First cryonics does not fit with existing western cultural views of death and medicine. Second, poor marketing, prohibitive cost, and the lack of involvement with the funerary industry may be significant factors impacting poor intake. Third, the cryonics discourse around ideas of ‘death’ constructs a barrier that prevents ‘outsiders’ from relating to the task of cryonicists. Fourth, the general public may have a poor understanding of this technology. Finally, there may be religious objections and cultural reductions due to the lack of ritual and thus no possibility of memorializing the dead, which impacts the human appeal of cryonics. (shrink)

We report specific heat and μSR measurements on Th and/or B substituted UBe13. The specific heat data show that either Th or B substitution reduces the Kondo temperature TK and increases the entropy at the superconducting transition by almost 20%, indicating an enhanced density of states. However, whereas μSR shows clear evidence for magnetic correlations for Th substitutions, no magnetism is observed for B substitutions. The enhanced specific heat jump in the B-substituted material is associated with a change in (...) the superconducting properties as TK is reduced. (shrink)

When a single beam-splitter receives two beams of bosons described by Fock states (Bose-Einstein condensates at very low temperatures), interesting generalizations of the two-photon Hong-Ou-Mandel effect take place for larger number of particles. The distributions of particles at two detectors behind the beam splitter can be understood as resulting from the combination of two effects, the spontaneous phase appearing during quantum measurement, and the quantum angle. The latter introduces quantum “population oscillations”, which can be seen as a generalized Hong-Ou-Mandel (...) effect, although they do not always correspond to even-odd oscillations. (shrink)

Cryoethics is a new theme within bioethics (see bioethics) concerned with the ethics of cryonic storage. Cryonics, which is also erroneously referred to as “cryogenic” technology, offers people the option of having their bodies or brain-stems preserved at very low temperatures after death in order to be revived at some point in the future when technology is sufficiently advanced to enable reanimation, and possibly immortality. The main issues in cryoethics center around whether it is ethical to use this technology, (...) and whether it is prudent to do so. While there are several prudential and ethical arguments against cryonic storage, there is only one argument in favor, but it is quite powerful: the possibility of cheating death for a few years, or even forever if technology advances enough in the time before revival (Shaw 2009). (shrink)

Every so often an experiment trying to give reliable evidence for a metallic hydrogen solid is reported. Such evidence is, however, not too convincing. As Eric Scerri has recently reiterated, “the jury is still out on that issue” . This search stems from the common spectroscopy shared by the hydrogen atom and all the alkali metal atoms, and perhaps is guided by a desire to place hydrogen atop the alkali metals, in Mendeleiev’s Table, reinforced by the fact pointed out by (...) Scerri that there is no other obvious place for hydrogen in said Table. But H2 is a light gas at room temperature, while Li, Na, K and the other alkali elements form solid metal crystals. At very low temperatures, of course, hydrogen solidifies, but it is formed by H2 molecules . Our purpose here is to use a new argument to break this impasse: “should H be grouped with the alkali metals with which it shares a common spectroscopy, but which solidifies in a completely different fashion?” This argument has been proposed before in a couple of papers in this journal to establish a similar question for He and the alkaline earths , as is discussed in “Precedents” section. (shrink)

In their article, ‘That is not dead which can eternal lie: the aestivation hypothesis for resolving Fermi’s paradox’, Sandberg et al. try to explain the Fermi paradox by claiming that Landauer’s principle implies that a civilization can in principle perform far more times more) irreversible logical operations if it conserves its resources until the distant future when the cosmic background temperature is very low. So perhaps aliens are out there, but quietly waiting. Sandberg et al. implicitly assume, however, (...) that computer-generated entropy can only be disposed of by transferring it to the cosmological background. In fact, while this assumption may apply in the distant future, our universe today contains vast reservoirs and other physical systems in non-maximal entropy states, and computer-generated entropy can be transferred to them at the adiabatic conversion rate of one bit of negentropy to erase one bit of error. This can be done at any time, and is not improved by waiting for a low cosmic background temperature. Thus aliens need not wait to be active. As Sandberg et al. do not provide a concrete model of the effect they assert, we construct one and show where their informal argument goes wrong. (shrink)

The osmotic activity produced by internal, non‐permeable, anionic nucleic acids and metabolites causes a persistent and life‐threatening cell swelling, or cellular edema, produced by the Gibbs‐Donnan effect. This evolutionary‐critical osmotic challenge must have been resolved by LUCA or its ancestors, but we lack a cell‐physiology look into the biophysical constraints to the solutions. Like mycoplasma, early cells conceivably preserved their volume with Cl−, Na+, and K+‐channels, Na+/H+‐exchangers, and a light‐dependent bacteriorhodopsin‐like H+‐pump. Here, I simulated protocells having these ionic‐permeabilities and inhabiting (...) an oceanic pond before the Great‐Oxygenation‐Event. Protocells showed better volume control and stable resting potentials at lower external pH and higher temperatures, favoring a certain type of extremophile life. Prevention of Na+‐influx at night, with low bacteriorhodopsin activity, required deep shutdown of highly voltage‐sensitive Na+‐channels and extremely selective K+‐channels, two conserved features essential for modern neuronal encoding. The Gibbs‐Donnan effect universality implies that extraterrestrial cells, if they exist, may reveal similar volume‐controlling mechanisms. (shrink)

We have investigated the nonlinear low-frequency microwave absorption of an ensemble of small metallic grains. Earlier Zhou et al. [Phys. Rev. Lett. 77, 1958 (1996)] have proved that linear absorption by such a system is due to a mesoscopic relaxation mechanism for which important contribution is from the grains with small level spacings between the ground state and the first excited state. Here we have shown further that such grains are anomalously sensitive to the field amplitude and the distribution of (...) level spacings. Since such a behavior depends on external magnetic field, we expect the appearance of a giant nonlinear magnetoresistance, as well as a very strong temperature dependence of the nonlinear microwave conductivity. (shrink)

In this essay, I consider three philosophical issues that arise in the environmental sciences. First, these sciences depend on mathematical models and simulations which are highly idealized and are coupled with very uncertain data. Why should we trust these models and simulations? Second, in standard hypothesis testing, the burden of proof is in favor of the null hypothesis which claims some causal factor has no effect. The alternative hypothesis is accepted only when the likelihood of the null hypothesis is (...) very low. Recently, some have argued that we should minimize Type II errors (not rejecting a false null) rather than Type I errors (rejecting a true null) given the environmental risks involved. I consider arguments for shifting this burden of proof when possible environmental harms are significant. Finally, in debates over global climate change, much is made of the apparent consensus concerning the effects of human induced greenhouse gas emissions on average surface temperatures. However, scientific methods are structured around dissent and criticism. Is consensus-based science orthogonal are even harmful to science? (shrink)

In this essay, I consider three philosophical issues that arise in the environmental sciences. First, these sciences depend on mathematical models and simulations which are highly idealized and are coupled with very uncertain data. Why should we trust these models and simulations? Second, in standard hypothesis testing, the burden of proof is in favor of the null hypothesis which claims some causal factor has no effect. The alternative hypothesis is accepted only when the likelihood of the null hypothesis is (...) very low. Recently, some have argued that we should minimize Type II errors (not rejecting a false null) rather than Type I errors (rejecting a true null) given the environmental risks involved. I consider arguments for shifting this burden of proof when possible environmental harms are significant. Finally, in debates over global climate change, much is made of the apparent consensus concerning the effects of human induced greenhouse gas emissions on average surface temperatures. However, scientific methods are structured around dissent and criticism. Is consensus-based science orthogonal are even harmful to science? (shrink)

The thermodynamic behavior is analyzed of a single classical charged particle in thermal equilibrium with classical electromagnetic thermal radiation, while electrostatically bound by a fixed charge distribution of opposite sign. A quasistatic displacement of this system in an applied electrostatic potential is investigated. Treating the system nonrelativistically, the change in internal energy, the work done, and the change in caloric entropy are all shown to be expressible in terms of averages involving the distribution of the position coordinates alone. A convenient (...) representation for the probability distribution is shown to be the ensemble average of the absolute square value of an expansion over the eigenstates of a Schrödinger-like equation, since the heat flow is shown to vanish for each hypothetical “state.” Subject to key assumptions highlighted here, the demand that the entropy be a function of state results in statistical averages in agreement with the form in quantum statistical mechanics. Examining the very low and very high temperature situations yields Planck's and Boltzmann's constants. The blackbody radiation spectrum is then deduced. From the viewpoint of the theory explored here, the method in quantum statistical mechanics of statistically counting the “states” at thermal equilibrium by using the energy eigenvalue structure, is simply a convenient counting scheme, rather than actually representing averages involving physically discrete energy states. (shrink)