3,430 research outputs found

    Participatory Mapping to Disrupt Unjust Urban Trajectories in Lima

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    This chapter shares the experience of two action research projects ReMap Lima and cLIMA sin Riego, where mapping has been used with three main objectives: to make visible what is otherwise ‘invisible’; to open up dialogue between different stakeholders in the city and to arrive at concrete actions, collectively negotiated between citizens and policy makers. Two case study sites were chosen in Lima, Peru: Barrios Altos (BA) in the historic centre and JosĂ© Carlos MariĂĄtegui (JCM) at the edge of the city. The approach adopted applies a participatory action methodology based on grounded applications and advanced technologies for community-led mapping and visualisation. The chapter reflects upon three interrelated sites of the mapping process: the reading, writing and audiencing of maps and explores how these can provide opportunities to break away from the polar positions often established between Claimant/ marginalised group and the state, thus aiming to contribute to a process of spatial co-learning across typically confronted actors. The two case studies show different possibilities for interrogating the city to provide a spatially and socially grounded way of co-producing knowledge for action that can contribute to the planning of just urban futures

    Report on estimating the size of dolphin schools, based on data obtained during a charter cruise of the M/V Gina Anne, October 11 -November 25, 1979

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    Estimates of dolphin school sizes made by observers and crew members aboard tuna seiners or by observers on ship or aerial surveys are important components of population estimates of dolphins which are involved in the yellowfin tuna fishery in the eastern Pacific. Differences in past estimates made from tuna seiners and research ships and aircraft have been noted by Brazier (1978). To compare various methods of estimating dolphin school sizes a research cruise was undertaken with the following major objectives: 1) compare estimates made by observers aboard a tuna seiner and in the ship's helicopter, from aerial photographs, and from counts made at the backdown channel, 2) compare estimates of observers who are told the count of the school size after making their estimate to the observer who is not aware of the count to determine if observers can learn to estimate more accurately, and 3) obtain movie and still photographs of dolphin schools of known size at various stages of chase, capture and release to be used for observer training. The secondary objectives of the cruise were to: 1) obtain life history specimens and data from any dolphins that were killed incidental to purse seining. These specimens and data were to be analyzed by the U.S. National Marine Fisheries Service ( NMFS ) , 2) record evasion tactics of dolphin schools by observing them from the helicopter while the seiner approached the school, 3) examine alternative methods for estimating the distance and bearing of schools where they were first sighted, 4) collect the Commission's standard cetacean sighting, set log and daily activity data and expendable bathythermograph data. (PDF contains 31 pages.

    Are changes in global precipitation constrained by the tropospheric energy budget?

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    Copyright © 2009 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act September 2010 Page 2 or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a web site or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/) or from the AMS at 617-227-2425 or [email protected] tropospheric energy budget argument is used to analyze twentieth-century precipitation changes. It is found that global and ocean-mean general circulation model (GCM) precipitation changes can be understood as being due to the competing direct and surface-temperature-dependent effects of external climate forcings. In agreement with previous work, precipitation is found to respond more strongly to anthropogenic and volcanic sulfate aerosol and solar forcing than to greenhouse gas and black carbon aerosol forcing per unit temperature. This is due to the significant direct effects of greenhouse gas and black carbon forcing. Given that the relative importance of different forcings may change in the twenty-first century, the ratio of global precipitation change to global temperature change may be quite different. Differences in GCM twentieth- and twenty-first-century values are tractable via the energy budget framework in some, but not all, models. Changes in land-mean precipitation, on the other hand, cannot be understood at all with the method used here, even if land–ocean heat transfer is considered. In conclusion, the tropospheric energy budget is a useful concept for understanding the precipitation response to different forcings but it does not fully explain precipitation changes even in the global mean

    Molecular modeling of an antigenic complex between a viral peptide and a class I major histocompatibility glycoprotein

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    Computer simulation of the conformations of short antigenic peptides (&lo residues) either free or bound to their receptor, the major histocompatibility complex (MHC)- encoded glycoprotein H-2 Ld, was employed to explain experimentally determined differences in the antigenic activities within a set of related peptides. Starting for each sequence from the most probable conformations disclosed by a pattern-recognition technique, several energyminimized structures were subjected to molecular dynamics simulations (MD) either in vacuo or solvated by water molecules. Notably, antigenic potencies were found to correlate to the peptides propensity to form and maintain an overall a-helical conformation through regular i,i + 4 hydrogen bonds. Accordingly, less active or inactive peptides showed a strong tendency to form i,i+3 hydrogen bonds at their Nterminal end. Experimental data documented that the C-terminal residue is critical for interaction of the peptide with H-2 Ld. This finding could be satisfactorily explained by a 3-D Q.S.A.R. analysis postulating interactions between ligand and receptor by hydrophobic forces. A 3-D model is proposed for the complex between a high-affinity nonapeptide and the H- 2 Ld receptor. First, the H-2 Ld molecule was built from X-ray coordinates of two homologous proteins: HLA-A2 and HLA-Aw68, energyminimized and studied by MD simulations. With HLA-A2 as template, the only realistic simulation was achieved for a solvated model with minor deviations of the MD mean structure from the X-ray conformation. Water simulation of the H-2 Ld protein in complex with the antigenic nonapeptide was then achieved with the template- derived optimal parameters. The bound peptide retains mainly its a-helical conformation and binds to hydrophobic residues of H-2 Ld that correspond to highly polymorphic positions of MHC proteins. The orientation of the nonapeptide in the binding cleft is in accordance with the experimentally determined distribution of its MHC receptor-binding residues (agretope residues). Thus, computer simulation was successfully employed to explain functional data and predicts a-helical conformation for the bound peptid

    Forcing and response in simulated 20th and 21st century surface energy and precipitation trends

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    A simple methodology is applied to a transient integration of the Met Office Hadley Centre Global Environmental Model version1 (UKMO-HadGEM1) fully coupled atmosphere-ocean general circulation model in order to separate forcing from climate response in simulated 20th century and future global mean surface energy and precipitation trends. Forcings include any fast responses that are caused by the forcing agent and that are independent of global temperature change. Results reveal that surface radiative forcing is dominated by shortwave forcing over the 20th and 21st centuries, which is strongly negative. However, when fast responses of surface turbulent heat fluxes are separated from climate feedbacks, and included in the forcing, net surface forcing becomes positive. The nonradiative forcings are the result of rapid surface and tropospheric adjustments and impact 20th century, as well as future, evaporation and precipitation trends. A comparison of energy balance changes in eight different climate models finds that all models exhibit a positive surface energy imbalance by the late 20th century. However, there is considerable disagreement in how this imbalance is partitioned between the longwave, shortwave, latent heat and sensible heat fluxes. In particular, all models show reductions in shortwave radiation absorbed at the surface by the late 20th century compared to the pre-industrial control state, but the spread of this reduction leads to differences in the sign of their latent heat flux changes and thus in the sign of their hydrological responses

    Urban risk readdressed: Bridging resilience-seeking practices in African cities

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    Throughout the Global South, urbanization is increasingly coupled with the production of risk accumulation cycles or urban “risk traps”, which are not exclusively driven but exacerbated by climate change. This is the case across many cities in sub Sahara Africa, where biophysical and socio-economic risk drivers combine to produce vicious cycles of unequal risk exposure and displacement, with severe impacts on the lives, livelihoods and assets of the urban poor and the city’s ecological and socio-economic future. Focusing on two case studies characterized by different approaches to the governance of disaster risk management (DRM) – Freetown (Sierra Leone) and Karonga (Malawi) – this chapter seeks to untangle the processes that drive risk accumulation over time and to appraise the resilience-seeking practices deployed and resources mobilized to mitigate, reduce, and prevent risk. It reflects on the findings from an action-research project conducted in the aforementioned cities, as part of a wider program entitled “Urban Africa Risk Knowledge” (Urban ARK). As such, it provides fresh insights into how the governance of urban resilience currently works in both contexts and on how to enhance the capacity to act of those most vulnerable to become trapped in risk accumulation cycles to disrupt these traps strategically, inclusively, and collectively. Our central argument is that the capacity of emerging DRM governance frameworks to disrupt urban risk traps is defined by the extent to which resilience-seeking is actually practiced in a relational way – that is acknowledging the multiple practices that converge in responding to risk and their relative capacities to disrupt the risk accumulation cycles that impact the most vulnerable. We further hypothesize that the differential ability of ongoing resilient-seeking practices to disrupt risk traps is shaped by the extent to which their governance expands the political space to enable abridged collective action among the urban poor, customary authorities, local governments and external agencies

    Two Loop Renormalization of Massive (p,q) Supersymmetric Sigma Models

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    We calculate the beta-functions of the general massive (p,q) supersymmetric sigma model to two loop order using (1,0) superfields. The conditions for finiteness are discussed in relation to (p,q) supersymmetry. We also calculate the effective potential using component fields to one loop order and consider the possibility of perturbative breaking of supersymmetry. The effect of one loop finite local counter terms and the ultra-violet behaviour of the off-shell (p,q) models to all orders in perturbation theory are also addressed.Comment: 43 pages phyzzx with 5 figure
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