Reducing Global Warming and Adapting to Climate Change: The Potential of Organic Agriculture

Climate change mitigation is urgent and adaptation to climate change is crucial, particularly in agriculture, where food security is at stake. Agriculture, currently responsible for 20-30% of global greenhouse gas emissions counting direct and indirect agricultural emissions), can however contribute to both climate change mitigation and adaptation. The main mitigation potential lies in the capacity of agricultural soils to sequester CO2 through building organic matter. This potential can be realized by employing sustainable agricultural practices, such as those commonly found within organic farming systems. Examples of these practices are the use of organic fertilizers and crop rotations including legumes leys and cover crops. Mitigation is also achieved in organic agriculture through the avoidance of open biomass burning and the avoidance of synthetic fertilizers and the related production emissions from fossil fuels. Common organic practices also contribute to adaptation. Building soil organic matter increases water retention capacity, and creates more stabile, fertile soils, thus reducing vulnerability to drought, extreme precipitation events, floods and water logging. Adaptation is further supported by increased agro-ecosystem diversity of organic farms, due to reduced nitrogen inputs and the absence of chemical pesticides. The high diversity together with the lower input costs of organic agriculture is key in reducing production risks associated with extreme weather events. All these advantageous practices are not exclusive to organic agriculture. However, they are core parts of the organic production system, in contrast to most non-organic agriculture, where they play a minor role only. Mitigation in agriculture cannot be restricted to the agricultural sector alone, though. Consumer behaviour strongly influences agricultural production systems, and thus their mitigation potential. Significant factors are meat consumption and food wastage. Any discussion on mitigation climate change in agriculture needs to address the entire food chain and needs to be linked to general sustainable development strategies. The main challenges to climate change mitigation and adaptation in organic agriculture and agriculture in general concern a)the understanding of some of the basic processes, such as the interaction of N2O emissions and soil carbon sequestration, contributions of roots to soil carbon sequestration and the life-cycle emissions of organic fertilizers such as compost; b) approaches for emissions accounting that adequately represent agricultural production systems with multiple and diverse outputs and that also encompass ecosystem services; c) the identification and implementation of most adequate policy frameworks for supporting mitigation and adaptation in agriculture, i.e: not putting systemic approaches at a disadvantage due to difficulties in the quantification of emissions, and in their allocation to single products; d) how to assure that the current focus on mitigation does not lead to neglect of the other sustainability aspects of agriculture, such as pesticide loads, eutrophication, acidification or soil erosion and e) the question how to address consumer behaviour and how to utilize the mitigation potential of changes in consumption patterns

New Constraints on Neutralino Dark Matter in the Supersymmetric Standard Model

We investigate the prospects for neutralino dark matter within the Supersymmetric Standard Model (SSM) including the constraints from universal soft supersymmetry breaking and radiative breaking of the electroweak symmetry. The latter is enforced by using the one-loop Higgs effective potential which automatically gives the one-loop corrected Higgs boson masses. We perform an exhaustive search of the allowed five-dimensional parameter space and find that the neutralino relic abundance $\Omega_\chi h^2_0$ depends most strongly on the ratio $\xi_0\equiv m_0/m_{1/2}$. For $\xi_0\gg1$ the relic abundance is almost always much too large, whereas for $\xi_0\ll1$ the opposite occurs. For $\xi_0\sim1$ there are wide ranges of the remaining parameters for which $\Omega_\chi\sim1$. We also determine that m_{\tilde q}\gsim250\GeV and m_{\tilde l}\gsim100\GeV are necessary in order to possibly achieve $\Omega_\chi\sim1$. These lower bounds are much weaker than the corresponding ones derived previously when radiative breaking was {\it not} enforced.Comment: 12 pages plus 6 figures (not included), CERN-TH.6584/92, CTP-TAMU-56/92, UAHEP921

A duality relation for fluid spacetime

We consider the electromagnetic resolution of gravitational field. We show that under the duality transformation, in which active and passive electric parts of the Riemann curvature are interchanged, a fluid spacetime in comoving coordinates remains invariant in its character with density and pressure transforming, while energy flux and anisotropic pressure remaining unaltered. Further if fluid admits a barotropic equation of state, $p = (\gamma - 1) \rho$ where $1 \leq \gamma \leq 2$, which will transform to $p = (\frac{2 \gamma}{3 \gamma - 2} - 1) \rho$. Clearly the stiff fluid and dust are dual to each-other while $\rho + 3 p =0$, will go to flat spacetime. However the n $(\rho - 3 p = 0)$ and the deSitter $(\rho + p = 0$) universes ar e self-dual.Comment: 5 pages, LaTeX version, Accepted in Classical Quantum Gravity as a Lette

Electric Fields Detected on Dye-Sensitized TiO2 Interfaces: Influence of Electrolyte Composition and Ruthenium Polypyridyl Anchoring Group Type

Electric fields at the dye-sensitized interface of anatase TiO2 nanocrystallites interconnected in a mesoporous thin film are reported using carboxylic acid-derivatized and phosphonic acid-derivatized ruthenium polypyridyl complexes. Systematic investigations with [Ru­(dtb)2(dpb)]­(PF6)2, where dtb is 4,4'-di-tert-butyl-2,2'-bipyridine and dpb is 4,4'-bis-(PO3H2)-2,2'-bipyridine, were carried out in conjunction with its carboxylic acid structural analogue. Electric fields attributed to cation adsorption were measured from a bathochromic (red) shift of the sensitizer's UV-visible absorption spectra upon replacement of neat acetonitrile solution with metal cation perchlorate acetonitrile electrolyte. Electric fields attributed to TiO2 electrons were measured from the hypsochromic (blue) shift of the absorption spectra upon electrochemical reduction of the sensitized TiO2 thin films. Electric fields, induced by either cation adsorption or electrochemically populated electrons, increase in magnitude following the same general cation-dependent trend (Na+ < Li+ < Ca2+ ≤ Mg2+ < Al3+), regardless of the sensitizer's anchoring group type. For the first time, surface electric fields in the presence of trivalent cations (i.e., Al3+) were measured using [Ru­(dtb)2(dpb)]­(PF6)2. The magnitude of electric fields detected by the carboxylic acid sensitizer was 3 times greater than that detected by the phosphonic acid structural analogue under the same experimental conditions. The influence of protons and water in the acetonitrile electrolyte was also quantified. The added water was found to decrease the electric field, whereas protons had a very similar influence as did metal cations

Semi-Empirical Bound on the Chlorinr-37 Solar Neutrino Experiment

The Kamiokande measurement of energetic Boron-8 neutrinos from the sun is used to set a lower bound on the contribution of the same neutrinos to the signal in the \Chlorine\ experiment. Implications for Beryllium-7 neutrinos are discussed.Comment: Latex, 6 pages + 1 postscript figure (included). UTAPHY-HEP-

Probing the classical field approximation - thermodynamics and decaying vortices

We review our version of the classical field approximation to the dynamics of a finite temperature Bose gas. In the case of a periodic box potential, we investigate the role of the high momentum cut-off, essential in the method. In particular, we show that the cut-off going to infinity limit decribes the particle number going to infinity with the scattering length going to zero. In this weak interaction limit, the relative population of the condensate tends to unity. We also show that the cross-over energy, at which the probability distribution of the condensate occupation changes its character, grows with a growing scattering length. In the more physical case of the condensate in the harmonic trap we investigate the dissipative dynamics of a vortex. We compare the decay time and the velocities of the vortex with the available analytic estimates.Comment: 7 pages, 8 eps figures, submitted to J. Optics B for the proceedings of the "Atom Optics and Interferometry" Lunteren 2002 worksho

Interactions of asbestos-activated macrophages with an experimental fibrosarcoma

Supernatants from in vivo asbestos-activated macrophages failed to show any cytostatic activity against a syngeneic fibrosarcoma cell line in vitro. UICC chrysotile-induced peritoneal exudate cells also failed to demonstrate any growth inhibitory effect on the same cells in Winn assays of tumor growth. Mixing UICC crocidolite with inoculated tumor cells resulted in a dose-dependent inhibition of tumor growth; this could, however, be explained by a direct cytostatic effect on the tumor cells of high doses of crocidolite, which was observed in vitro

Spectral Line Imaging Observations of 1E0102.2-7219

E0102-72 is the second brightest X-ray source in the Small Magellanic Cloud and the brightest supernova remnant in the SMC. We observed this SNR for ~140 ksec with the High Energy Transmission Gratings (HETG) aboard the Chandra X-ray Observatory. The small angular size and high surface brightness make this an excellent target for HETG and we resolve the remnant into individual lines. We observe fluxes from several lines which include O VIII Ly$\alpha$, Ly$\beta$, and O VII along with several lines from Ne X, Ne IX and Mg XII. These line ratios provide powerful constraints on the electron temperature and the ionization age of the remnant.Comment: To appear in "Young Supernova Remnants" (11th Annual Astrophysics Conference in Maryland), S. S. Holt & U. Hwang (eds), AIP, New York (2001

Vortex Dynamics in Self-Dual Chern-Simons Higgs Systems

We consider vortex dynamics in self-dual Chern-Simons Higgs systems. We show that the naive Aharanov-Bohm phase is the inverse of the statistical phase expected from the vortex spin, and that the self-dual configurations of vortices are degenerate in energy but not in angular momentum. We also use the path integral formalism to derive the dual formulation of Chern-Simons Higgs systems in which vortices appear as charged particles. We argue that besides the electromagnetic interaction, there is an additional interaction between vortices, the so-called Magnus force, and that these forces can be put together into a single `dual electromagnetic' interaction. This dual electromagnetic interaction leads to the right Aharanov-Bohm phase. We also derive and study the effective action for slowly moving vortices, which contains terms both linear and quadratic in the vortex velocity.Comment: 36 pages and three figures (available under request), Columbia and CERN preprin

Neutrino Oscillations and Moments of Electron Spectra

We show that the effects of neutrino oscillations on 8B solar neutrinos are described well by the first two moments (the average and the variance) of the energy distribution of scattered or recoil electrons. For the SuperKamiokande and the Sudbury Neutrino Observatory experiments, the differences between the moments calculated with oscillations and the standard, no-oscillation moments are greater than 3 standard deviations for a significant fraction of the neutrino mass-mixing (Delta m^2, sin^2 2 theta) parameter space.Comment: 16 pages, Latex, text+figures. To be published in Physical Review C, January 199