822 research outputs found
Climate change, society issues and sustainable agriculture
Despite its prediction 100 years ago by scientists studying CO2, man-made climate change has been officially recognised only in 2007 by the Nobel prize committee. Climate changes since the industrial revolution have already deeply impacted ecosystems. I report major impacts of climate change on waters, terrestrial ecosystems, agriculture, and economy in Europe. The lesson of the climate change story is that humans do not learn from scientists until it really hurts. Furthermore, all society issues cannot be solved anymore using the old, painkiller approach because all issues are now huge, linked, global and fast-developing. In that respect, actual society structures are probably outdated. Here, agronomists are the most advanced scientists to solve society issues because they master the study of complex systems, from the molecule to the global scale. Now more than ever agriculture is a central point to which all society issues are bound. Indeed, humans eat food
Lord Rutherford of Nelson, His 1908 Nobel Prize in Chemistry and Why He Didn't Get a Second Prize
"I have dealt with many different transformations with various periods of
time, but the quickest that I have met was my own transformation in one moment
from a physicist to a chemist."
Ernest Rutherford (Nobel Banquet, 1908)
This article is about how Ernest Rutherford (1871-1937) got the 1908 Nobel
Prize in Chemistry and why he did not get a second Prize for his subsequent
outstanding discoveries in physics, specially the discovery of the atomic
nucleus and the proton. Who were those who nominated him and who did he
nominate for the Nobel Prizes.
In order to put the Prize issue into its proper context, I will briefly
describe Rutherford's whereabouts.
Rutherford, an exceptionally gifted scientist who revolutionized chemistry
and physics, was moulded in the finest classical tradition. What were his
opinions on some scientific issues such as Einstein's photon, uncertainty
relations and the future prospects for atomic energy? What would he have said
about the "Theory of Everything"?Comment: Extended version of an invited talk presented at the neutrino
conference "Neutrino 2008", Christchurch, New Zealand, 25-31 May 200
Evidence for Life on Earth before 3,800 Million Years Ago
It is unknown when life first appeared on Earth. The earliest known microfossils (approx. 3,500 Myr before present) are structurally complex, and if it is assumed that the associated organisms required a long time to develop this degree of complexity, then the existence of life much earlier than this can be argued. But the known examples of crustal rocks older than approx. 3,500 Myr have experienced intense metamorphism, which would have obliterated any fragile microfossils contained therein. It is therefore necessary to search for geochemical evidence of past biotic activity that has been preserved within minerals that are resistant to metamorphism. Here we report ion-microprobe measurements of the carbon-isotope composition of carbonaceous inclusions within grains of apatite (basic calcium phosphate) from the oldest known sediment sequences a approx. 3,800 Myr-old banded iron formation from the Isua supracrustal belt, West Greenland, and a similar formation from the nearby Akilia island that is possibly older than 3,850 Myr. The carbon in the carbonaceous inclusions is isotopically light, indicative of biological activity; no known abiotic process can explain the data. Unless some unknown abiotic process exists which is able both to create such isotopically light carbon and then selectively incorporate it into apatite grains, our results provide evidence for the emergence of life on Earth by at least 3,800 Myr before present
Carbon flux from decomposing wood and its dependency on temperature, wood N2 fixation rate, moisture and fungal composition in a Norway spruce forest
201
Dynamics of the condensate in zero-range processes
For stochastic processes leading to condensation, the condensate, once it is
formed, performs an ergodic stationary-state motion over the system. We analyse
this motion, and especially its characteristic time, for zero-range processes.
The characteristic time is found to grow with the system size much faster than
the diffusive timescale, but not exponentially fast. This holds both in the
mean-field geometry and on finite-dimensional lattices. In the generic
situation where the critical mass distribution follows a power law, the
characteristic time grows as a power of the system size.Comment: 27 pages, 7 figures. Minor changes and updates performe
Correlations in Nuclear Arrhenius-Type Plots
Arrhenius-type plots for multifragmentation process, defined as the
transverse energy dependence of the single-fragment emission-probability,
-ln(p_{b}) vs 1/sqrt(E_{t}), have been studied by examining the relationship of
the parameters p_{b} and E_{t} to the intermediate-mass fragment multiplicity
. The linearity of these plots reflects the correlation of the fragment
multiplicity with the transverse energy. These plots may not provide thermal
scaling information about fragment production as previously suggested.Comment: 12 pages, Latex, 3 Postscript figures include
Person-Affecting Paretian Egalitarianism with Variable Population Size
http://web.missouri.edu/~klinechair/on-line%20papers/person-affecting%20APE.docWhere there is a fixed population (i.e., who exists does not depend on what choice an agent makes), the deontic version of anonymous Paretian egalitarianism holds that an option is just if and only if (1) it is anonymously Pareto optimal (i.e., no feasible alternative has a permutation that is Pareto superior), and (2) it is no less equal than any other anonymously Pareto optimal option. We shall develop and discuss a version of this approach for the variable population case (i.e., where who exists does depend on what choice an agent makes). More specifically, we shall develop and discuss it in the context of a person-affecting framework—in which an option is just if and only if it wrongs no one according to certain plausible conditions on wronging
Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics
The atmospheric greenhouse effect, an idea that many authors trace back to
the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896),
and which is still supported in global climatology, essentially describes a
fictitious mechanism, in which a planetary atmosphere acts as a heat pump
driven by an environment that is radiatively interacting with but radiatively
equilibrated to the atmospheric system. According to the second law of
thermodynamics such a planetary machine can never exist. Nevertheless, in
almost all texts of global climatology and in a widespread secondary literature
it is taken for granted that such mechanism is real and stands on a firm
scientific foundation. In this paper the popular conjecture is analyzed and the
underlying physical principles are clarified. By showing that (a) there are no
common physical laws between the warming phenomenon in glass houses and the
fictitious atmospheric greenhouse effects, (b) there are no calculations to
determine an average surface temperature of a planet, (c) the frequently
mentioned difference of 33 degrees Celsius is a meaningless number calculated
wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the
assumption of a radiative balance is unphysical, (f) thermal conductivity and
friction must not be set to zero, the atmospheric greenhouse conjecture is
falsified.Comment: 115 pages, 32 figures, 13 tables (some typos corrected
Comparative Survival Analysis of Deinococcus Radiodurans and the Haloarchaea Natrialba Magadii and Haloferax Volcanii, Exposed to Vacuum Ultraviolet Irradiation
The haloarchaea Natrialba magadii and Haloferax volcanii, as well as the
radiation-resistant bacterium Deinococcus radiodurans, were exposed to
vacuum-UV (V-UV) radiation at the Brazilian Synchrotron Light Laboratory
(LNLS). Cell monolayers (containing 105 - 106 cells per sample) were prepared
over polycarbonate filters and irradiated under high vacuum (10-5 Pa) with
polychromatic synchrotron radiation. N. magadii was remarkably resistant to
high vacuum with a survival fraction of ((3.77 \pm 0.76) x 10-2), larger than
the one of D. radiodurans ((1.13 \pm 0.23) x 10-2). The survival fraction of
the haloarchaea H. volcanii, of ((3.60 \pm 1.80) x 10-4), was much smaller.
Radiation resistance profiles were similar between the haloarchaea and D.
radiodurans for fluencies up to 150 J m-2. For fluencies larger than 150 J m-2
there was a significant decrease in the survival of haloarchaea, and in
particular H. volcanii did not survive. Survival for D. radiodurans was 1%
after exposure to the higher V-UV fluency (1350 J m-2) while N. magadii had a
survival lower than 0.1%. Such survival fractions are discussed regarding the
possibility of interplanetary transfer of viable micro-organisms and the
possible existence of microbial life in extraterrestrial salty environments
such as the planet Mars and the Jupiter's moon Europa. This is the first work
reporting survival of haloarchaea under simulated interplanetary conditions.Comment: Draft version (without figures), Accepted for publication in
Astrobiolog
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