Spatial patterns of tree yield explained by endogenous forces through a correspondence between the Ising model and ecology.

Spatial patterning of periodic dynamics is a dramatic and ubiquitous ecological phenomenon arising in systems ranging from diseases to plants to mammals. The degree to which spatial correlations in cyclic dynamics are the result of endogenous factors related to local dynamics vs. exogenous forcing has been one of the central questions in ecology for nearly a century. With the goal of obtaining a robust explanation for correlations over space and time in dynamics that would apply to many systems, we base our analysis on the Ising model of statistical physics, which provides a fundamental mechanism of spatial patterning. We show, using 5 y of data on over 6,500 trees in a pistachio orchard, that annual nut production, in different years, exhibits both large-scale synchrony and self-similar, power-law decaying correlations consistent with the Ising model near criticality. Our approach demonstrates the possibility that short-range interactions can lead to long-range correlations over space and time of cyclic dynamics even in the presence of large environmental variability. We propose that root grafting could be the common mechanism leading to positive short-range interactions that explains the ubiquity of masting, correlated seed production over space through time, by trees

The ‘CSA Papers’: Call for Book Chapter Proposals

The World Agroforestry Centre (ICRAF), in collaboration with the CGIAR Research Programme on Climate Change, Agriculture, and Food Security (CCAFS) invites scientists and development actors to submit applications for publication of book chapter in an open-access book investigating obstacles to scaling up climate-smart agriculture (CSA), The CSA Papers

The CSA Papers: Critical investigations to support climate-smart agriculture development. An effort to analyze, publish, and present previously unreleased data on CSA

The CSA Papers aim to generate critical insights into five key areas of CSA based on unpublished scientific information. Contributors of Papers will participate in a writeshop, be provided honoraria, and be eligible for travel grants to showcase their work

Fractals and dynamical chaos in a random 2D Lorentz gas with sinks

Two-dimensional random Lorentz gases with absorbing traps are considered in which a moving point particle undergoes elastic collisions on hard disks and annihilates when reaching a trap. In systems of finite spatial extension, the asymptotic decay of the survival probability is exponential and characterized by an escape rate, which can be related to the average positive Lyapunov exponent and to the dimension of the fractal repeller of the system. For infinite systems, the survival probability obeys a stretched exponential law of the form P(c,t)~exp(-Ct^{1/2}). The transition between the two regimes is studied and we show that, for a given trap density, the non-integer dimension of the fractal repeller increases with the system size to finally reach the integer dimension of the phase space. Nevertheless, the repeller remains fractal. We determine the special scaling properties of this fractal.Comment: 40 pages, 10 figures, preprint for Physica

‘CSA Plan’: A guide to scaling climate-smart agriculture - Concepts and lessons from designing CSA programs and policies in sub-Saharan Africa

Large scale investment is needed to create climate-smart agriculture (CSA) systems. While many government and development agencies are integrating CSA into their policies, programmes, plans and projects, there is little guidance for operational planning and implementation on ways to be climate-smart. Here we present “CSA-Plan”. CSA-Plan frames actions needed to design and execute CSA programs into four components—1) situation analysis, 2) targeting and prioritizing, 3) program design, and 4) monitoring and evaluation. Each component yields concrete information to operationalize CSA development separating it from traditional agriculture development. Already, CSA-Plan has shown the capacity to change the discussion around CSA implementation. With iterative co-development, the approaches will become only more useful, relevant and legitimate to governments, civil society and the private sector alike

‘CSA-Plan’: strategies to put Climate-Smart Agriculture (CSA) into practice

Large-scale investment is needed to create climate-smart agriculture (CSA) systems. While many government and development agencies are integrating CSA into their policies, programmes, plans and projects, there is little guidance for operational planning and implementation on ways to be climate-smart. Here we present ‘CSA-Plan’. CSA-Plan frames actions needed to design and execute CSA programmes into four components – (i) situation analysis, (ii) targeting and prioritising, (iii) programme design, and (iv) monitoring and evaluation. Each component yields concrete information to operationalise CSA development, separating it from traditional agriculture development. Already, CSA-Plan has shown the capacity to change the discussion around CSA implementation. With iterative co-development, the approaches will become ever more useful, relevant and legitimate to governments, civil society and the private sector alike

Isaac Bashevis Singer Memorial Archive Library

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1993.Includes bibliographical references (p. 85-88).The design of this library is based upon two architectural concepts: the concept of defensive architecture, which is the architectural response to perceived threat, and the concept of the building as metaphysical model of the universe, having domains of sacred and profane space. I have long been intrigued by defensive architecture, by the forms it generates in response to perceived threat. The towers, mask-like facades, and labyrinthine passageways remain intriguing long after the war is over. Castles and fortifications are the architectural manifestation of an abrupt discontinuity in the organization of space. A stark polarity is created, a partition between inside and out, ours and theirs, us and them. The stark form of a defensive structure derives enormous formal power from this conflict of opposites. Tamer, gentler forms of this concept may be found in the form of monasteries, and madrasas. These share the qualities of retreat and seclusion, but for a different purpose - to be able to concentrate better on learning, and/or prayer. Their seclusion from the outside world is not a hostile act but rather a desire to intensify their inner world of prayer and study. These building types share qualities of having walls which segregate opposing conditions, as in defensive architecture, but differ in that the thing being excluded from the protected domain are of a spiritual nature, rather than physical threats. Sacred space is a domain generated by an origin which marks a vertical break in space from the ordinary ...by H.F. Tzviyah Rosenstock.M.Arch

Why Be Regular? Part I

We provide a novel perspective on "regularity" as a property of representations of the Weyl algebra. We first critique a proposal by Halvorson [2004, "Complementarity of representations in quantum mechanics", Studies in History and Philosophy of Modern Physics 35(1), pp. 45--56], who argues that the non-regular "position" and "momentum" representations of the Weyl algebra demonstrate that a quantum mechanical particle can have definite values for position or momentum, contrary to a widespread view. We how that there are obstacles to such an intepretation of non-regular representations. In Part II, we propose a justification for focusing on regular representations, pace Halvorson, by drawing on algebraic methods