Governing climate change for a just city: challenges and lessons from Maputo, Mozambique

As new forms of governance for climate change emerge in African cities, will they enable emancipatory and socially progressive transformations or will they exacerbate existing inequality, poverty and vulnerability patterns? This paper presents one of the case studies developed by UN-Habitat Cities and Climate Change Initiative in Maputo, Mozambique. The case analyses first, the production of urban vulnerabilities under climate change, and second, the existing governance arrangements for climate change in the city. Building on the lessons of the case study, the paper argues that to ensure that new forms of climate change governance lead to socially and environmentally just outcomes climate change interventions should, at least, meet two conditions: first, they should consider the close interactions between social and ecological elements and, specially, how patterns of urban inequality interact with environmental factors; second, they should recognise the opportunities in African cities through a broad notion of governance that looks beyond the government as the sole agent of urban change

Thermodynamics of Ferrotoroidic Materials: Toroidocaloric Effect

The three primary ferroics, namely ferromagnets, ferroelectrics and ferroelastics exhibit corresponding large (or even giant) magnetocaloric,electrocaloric and elastocaloric effects when a phase transition is induced by the application of an appropriate external field. Recently the suite of primary ferroics has been extended to include ferrotoroidic materials in which there is an ordering of toroidic moments in the form of magnetic vortex-like structures, examples being LiCo(PO_4)_3 and Ba_2CoGe_2O_7. In the present work we formulate the thermodynamics of ferrotoroidic materials. Within a Landau free energy framework we calculate the toroidocaloric effect by quantifying isothermal entropy change (or adiabatic temperature change) in the presence of an applied toroidic field when usual magnetization and polarization may also be present simultaneously. We also obtain a nonlinear Clausius-Clapeyron relation for phase coexistence.Comment: 10 pages, 5 Figure

Knowledge co-production for urban equality

This working paper serves as the basis for a critical examination of the notion of knowledge co-production. The paper examines how the idea of knowledge co-production has emerged in relation to the parallel but distinct concept of service co-production and the participatory development planning tradition. It also examines the variety of processes of knowledge co-production that may take place in the context of academic research. In doing so, the working paper highlights the centrality of knowledge co-production in the Knowledge in Action for Urban Equality (KNOW) project’s research strategy, with a focus on actionable knowledge that may support transformative trajectories towards urban equality. Such an approach is based on the view that knowledge production underpins the process, ethics, and outcomes of any urban development intervention

Alliances, allyship and activism: the value of international partnerships for co-producing just cities

This paper provides a distinctive analysis of the value of international intermediation alliances for co-production, based on the way they operate in practice. While much attention is paid to ideal or normative models of co-production, there is less understanding of the complexities that pervade co-production practices in specific contexts or how this shapes outcomes. Despite longstanding critiques and reflection, international partnerships can reinforce unequal power dynamics embedded in already unequal global research and knowledge production circuits. However, such partnerships, despite their structural problems, can also give rise to more informal relations wherein the long-term value of international co-production inheres. We call for a re-examination of these complex sets of informal relations, beyond the structures of partnerships, that enable co-production across local and global divides. Drawing on comparative international evidence, we propose a framework for understanding and action based on the concepts of alliances, allyship and activism. These three characteristics of international co-production partnerships can constitute socio-material infrastructures that help maintain relationships of solidarity and care over time beyond the remit of individual projects. While this is relevant in any co-production context it becomes particularly important in international research projects so that they do not paradoxically reproduce colonising structures of knowledge production in the search for more just cities

Electrical characterization of atomic-layer-deposited hafnium oxide films from hafnium tetrakis(dimethylamide) and water/ozone: Effects of growth temperature, oxygen source, and postdeposition annealing

The electrical properties of HfO2-based metal-insulator- semiconductor capacitors have been systematically investigated by means of I-V and C-V characteristics, admittance spectroscopy, deep level transient spectroscopy, conductance transient, and flat band voltage transient techniques. Attention is also given to the study of the temperature dependence of the leakage current. HfO2 films were grown on p-type silicon substrates by atomic layer deposition using hafnium tetrakis(dimethylamide) as hafnium precursor, and ozone or water as oxygen precursors. The growth temperature ranged from 150 to 350 °C. Low growth temperatures prevent decomposition and high growth rate, as well as high contamination levels. As a result, the leakage current is lower for lower deposition temperatures. Some of the deposited samples were submitted to a postdeposition annealing at 650 °C in N2 atmosphere, showing a decrease in the leakage current and an increase in the equivalent oxide thickness (EOT), whereas interfacial state density increases and defect density inside the dielectric bulk decreases. Regarding dielectric reliability, in our experimental conditions, HfO 2 layers grown at 150 °C exhibit the largest EOT and breakdown voltage. The electrical behaviour is clearly linked with structural properties, and especially with the formation of an interfacial layer between the HfO 2 layer and the silicon substrate, as well as with the presence of several impurities. © 2013 American Vacuum Society.Peer Reviewe

Prediction of large for gestational age by ultrasound at 35 weeks and impact of ultrasound-delivery interval: Comparison of 6 standards

Objective: The aim of the study was to assess the predictive ability of the ultrasound estimated percentile weight (EPW) at 35 weeks to predict large for gestational age (LGA) at term delivery according to 6 growth standards, including population, population-customized, and international references. The secondary objectives were to determine its predictive ability to detect adverse perinatal outcomes (APOs) and whether the ultrasound-delivery interval influences the detection rate of LGA newborns. Methods: This was a retrospective cohort study of 9, 585 singleton pregnancies. Maternal clinical characteristics, fetal ultrasound data obtained at 35 weeks, and pregnancy and perinatal outcomes were used to calculate EPWs to predict LGAs at delivery according to the customized and the non-customized (NC) Miguel Servet University Hospital (MSUH), the customized Figueras, the NC Fetal Medicine Foundation (FMF), the NC INTERGROWTH-21st, and the NC World Health Organization (WHO) standards. Results: For a 10% false-positive rate, detection rates for total LGAs at delivery ranged from 31.2% with the WHO (area under the curve [AUC] 0.77; 95% confidence interval [CI], 0.76-0.79) to 56.5% with the FMF standard (AUC 0.85; 95% CI, 0.84-0.86). Detection rates and values of AUCs to predict LGAs by ultrasound-delivery interval (range 1-6 weeks) show higher detection rates as the interval decreases. APO detection rates ranged from 2.5% with the WHO to 12.6% with the Figueras standard. Conclusion: The predictive ability of ultrasound estimated fetal weight at 35 weeks to detect LGA infants is significantly greater for FMF and MSUH NC standards. In contrast, the APO detection rate is significantly greater for customized standards. The shorter ultrasound-delivery interval relates to better prediction rates

Vacancy-assisted domain-growth in asymmetric binary alloys: a Monte Carlo study

A Monte Carlo simulation study of the vacancy-assisted domain-growth in asymmetric binary alloys is presented. The system is modeled using a three-state ABV Hamiltonian which includes an asymmetry term, not considered in previous works. Our simulated system is a stoichiometric two-dimensional binary alloy with a single vacancy which evolves according to the vacancy-atom exchange mechanism. We obtain that, compared to the symmetric case, the ordering process slows down dramatically. Concerning the asymptotic behavior it is algebraic and characterized by the Allen-Cahn growth exponent x=1/2. The late stages of the evolution are preceded by a transient regime strongly affected by both the temperature and the degree of asymmetry of the alloy. The results are discussed and compared to those obtained for the symmetric case.Comment: 21 pages, 9 figures, accepted for publication in Phys. Rev.

Electrophoretic mobility of supercoiled, catenated and knotted DNA molecules

We systematically varied conditions of two-dimensional (2D) agarose gel electrophoresis to optimize separation of DNA topoisomers that differ either by the extent of knotting, the extent of catenation or the extent of supercoiling. To this aim we compared electrophoretic behavior of three different families of DNA topoisomers: (i) supercoiled DNA molecules, where supercoiling covered the range extending from covalently closed relaxed up to naturally supercoiled DNA molecules; (ii) postreplicative catenanes with catenation number increasing from 1 to ∼15, where both catenated rings were nicked; (iii) knotted but nicked DNA molecules with a naturally arising spectrum of knots. For better comparison, we studied topoisomer families where each member had the same total molecular mass. For knotted and supercoiled molecules, we analyzed dimeric plasmids whereas catenanes were composed of monomeric forms of the same plasmid. We observed that catenated, knotted and supercoiled families of topoisomers showed different reactions to changes of agarose concentration and voltage during electrophoresis. These differences permitted us to optimize conditions for their separation and shed light on physical characteristics of these different types of DNA topoisomers during electrophoresi

Study of TiN/Ti/HfO2/W resistive switching devices: characterization and modeling of the set and reset transitions using an external capacitor discharge

Producción CientíficaIn this work, we have studied the control of set and the reset transitions in TiN/Ti/HfO2/W resistive switching devices using a new approach based on the injection of a limited amount of charge through the use of a capacitor discharge. Instead of applying conventional voltage or current signals, the capacitor discharge through the devices is able to perform both transitions. An accumulative process is observed if we apply consecutive discharges, and, when increasing the capacitor voltage in each discharge, the transitions between both resistance states are completed. In addition, it has been shown that faster transitions require larger capacitor voltages. Further, the electrical results were used to tune the dynamic memdiode model, which was employed to simulate set and reset processes driven by the capacitor discharges. The model successfully reproduced the measured memristor response to the capacitor discharge.Ministerio de Ciencia, Innovación y Universidades y programa FEDER (proyectos TEC2017-84321-C4-1-R, TEC2017-84321-C4-2-R, TEC2017-84321-C4-3-R y TEC2017-84321-C4-4-R

Analysis and control of the intermediate memory states of RRAM devices by means of admittance parameters

Producción CientíficaA thorough study of the admittance of TiN/Ti/HfO2/W bipolar resistive memories [resistance random access memory (RRAM)] was carried out under different bias conditions and in a wide range of ac signal frequencies. We demonstrate that a continuum of intermediate states can be obtained by applying appropriate dc bias waveforms. Cumulative writing and erasing admittance cycles were performed by applying triangular voltage waveform of increasing amplitude. The influence of the initial conditions on the variation of the real (conductance) and imaginary (susceptance) components of the admittance is described. An accurate control of the memory state is achieved both in terms of the conductance and the susceptance by means of an adequate selection of the voltage values previously applied. A method to obtain three-dimensional voltage-conductance-susceptance state-plots is described in detail. Memory maps of admittance parameters as a function of the programming voltage are made by sensing the memory state at 0 V, without static power consumption. The multilevel nature of RRAM devices and their suitability for neuromorphic computation are demonstrated.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (grants TEC2014-52152-C3-3-R and TEC2014- 52152-C3-1-R