1,596 research outputs found

    What is the scientific basis for climate-smart agriculture?

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    Climate-smart agriculture (CSA) is a systematic approach to agricultural development. It intends to address climate change and food security challenges simultaneously across levels, from field management to national policy, with goals to 1) improve food security and agricultural productivity, 2) increase the resilience of farming systems to climate change, and 3) mitigate greenhouse gas (GHG) emissions or sequester carbon. After the introduction of the CSA concept in 2010, development organizations, national governments, and donors have quickly adopted a “climate-smart” agenda

    New Combinations: Changing Technologies and Infrastructures and the Business Organizations That Will Deal with Them.

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    This tale is somewhat unique. It is probably one of the few panels, or the only panel in which there is a certain level of agreement. In fact, every one in this room probably has the basic agreement with this panel, that changes in regulation and changes in policy that we are struggling with are driven by changes in technology. This panel has been put together to look at changes in technology. It has three overall goals. The first is, as you heard one of the panels this morning talk about, to talk about technology itself to try to gain some type of understanding. As regulators or practitioners of law in the area, it is hard to be effective without some type of understanding of just what the technology is that we are supposed to be regulating or trying to give people advice concerning. The second area that this panel will hopefully inform us on is how technology continues to change. Many times we look back and see how technological changes have occurred, and how they have forced us to change. However, there is little consideration for the fact that these technologies continue to change and there will be other challenges or maybe even solutions to current problems that will result from that change in technology. And the final area we hope to provide information on is, as technology changes and as it causes regulators to address new issues, how the utilities, are themselves very different, and have been changed and shaped by this changing technology. This group, I think, can demonstrate very well how the conversion of the different technologies have shaped most of the companies and people who are on the panel

    Kinetics of stochastically-gated diffusion-limited reactions and geometry of random walk trajectories

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    In this paper we study the kinetics of diffusion-limited, pseudo-first-order A + B -> B reactions in situations in which the particles' intrinsic reactivities vary randomly in time. That is, we suppose that the particles are bearing "gates" which interchange randomly and independently of each other between two states - an active state, when the reaction may take place, and a blocked state, when the reaction is completly inhibited. We consider four different models, such that the A particle can be either mobile or immobile, gated or ungated, as well as ungated or gated B particles can be fixed at random positions or move randomly. All models are formulated on a dd-dimensional regular lattice and we suppose that the mobile species perform independent, homogeneous, discrete-time lattice random walks. The model involving a single, immobile, ungated target A and a concentration of mobile, gated B particles is solved exactly. For the remaining three models we determine exactly, in form of rigorous lower and upper bounds, the large-N asymptotical behavior of the A particle survival probability. We also realize that for all four models studied here such a probalibity can be interpreted as the moment generating function of some functionals of random walk trajectories, such as, e.g., the number of self-intersections, the number of sites visited exactly a given number of times, "residence time" on a random array of lattice sites and etc. Our results thus apply to the asymptotical behavior of the corresponding generating functions which has not been known as yet.Comment: Latex, 45 pages, 5 ps-figures, submitted to PR

    Number of Common Sites Visited by N Random Walkers

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    We compute analytically the mean number of common sites, W_N(t), visited by N independent random walkers each of length t and all starting at the origin at t=0 in d dimensions. We show that in the (N-d) plane, there are three distinct regimes for the asymptotic large t growth of W_N(t). These three regimes are separated by two critical lines d=2 and d=d_c(N)=2N/(N-1) in the (N-d) plane. For d<2, W_N(t)\sim t^{d/2} for large t (the N dependence is only in the prefactor). For 2<d<d_c(N), W_N(t)\sim t^{\nu} where the exponent \nu= N-d(N-1)/2 varies with N and d. For d>d_c(N), W_N(t) approaches a constant as t\to \infty. Exactly at the critical dimensions there are logaritmic corrections: for d=2, we get W_N(t)\sim t/[\ln t]^N, while for d=d_c(N), W_N(t)\sim \ln t for large t. Our analytical predictions are verified in numerical simulations.Comment: 5 pages, 3 .eps figures include

    The roots of "Western European societal evolution". A concept of Europe by JenƑ SzƱcs

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    JenƑ SzƱcs wrote his essay entitled Sketch on the three regions of Europe in the early 1980s in Hungary. During these years, a historically well-argued opinion emphasising a substantial difference between Central European and Eastern European societies was warmly received in various circles of the political opposition. In a wider European perspective SzƱcs used the old “liberty topos” which claims that the history of Europe is no other than the fulfillment of liberty. In his Sketch, SzƱcs does not only concentrate on questions concerning the Middle Ages in Western Europe. Yet it is this stream of thought which brought a new perspective to explaining European history. His picture of the Middle Ages represents well that there is a way to integrate all typical Western motifs of post-war self-definition into a single theory. Mainly, the “liberty motif”, as a sign of “Europeanism” – in the interpretation of Bibó’s concept, Anglo-saxon Marxists and Weber’s social theory –, developed from medieval concepts of state and society and from an analysis of economic and social structures. SzƱcs’s historical aspect was a typical intellectual product of the 1980s: this was the time when a few Central European historians started to outline non-Marxist aspects of social theory and categories of modernisation theories, but concealing them with Marxist terminology

    Multiparticle trapping problem in the half-line

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    A variation of Rosenstock's trapping model in which NN independent random walkers are all initially placed upon a site of a one-dimensional lattice in the presence of a {\em one-sided} random distribution (with probability cc) of absorbing traps is investigated. The probability (survival probability) ΊN(t)\Phi_N(t) that no random walker is trapped by time tt for N≫1N \gg 1 is calculated by using the extended Rosenstock approximation. This requires the evaluation of the moments of the number SN(t)S_N(t) of distinct sites visited in a {\em given} direction up to time tt by NN independent random walkers. The Rosenstock approximation improves when NN increases, working well in the range Dtln⁥2(1−c)â‰Șln⁥NDt\ln^2(1-c) \ll \ln N, DD being the diffusion constant. The moments of the time (lifetime) before any trapping event occurs are calculated asymptotically, too. The agreement with numerical results is excellent.Comment: 11 pages (RevTex), 6 figures (eps). To be published in Physica

    Efficacy and Safety of Technosphere Inhaled Insulin Compared With Technosphere Powder Placebo in Insulin-Naive Type 2 Diabetes Suboptimally Controlled With Oral Agents

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    OBJECTIVE—This double-blind, placebo-controlled, randomized, multicenter, parallel-group study compared the efficacy, safety, and tolerability of Technosphere insulin with Technosphere powder as placebo in insulin-naive type 2 diabetic patients whose diabetes was suboptimally controlled with oral antidiabetic agents
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