Urban extractivism. Contesting megaprojects in Mexico City, rethinking urban values

Urban extractivism is an emergent concept increasingly discussed within Latin America-based scholarship but less known in anglophone urban geography. The devastating social and environmental impact of large-scale natural resource extraction, usually accompanied and driven by infrastructure megaprojects, is the main domain to which activists and scholars are currently applying the concept of extractivism. However, extractivism-related accumulation also applies to urban contexts, as for instance, scholars argue using this lens to analyze the production of exclusive urban territories in central Buenos Aires. In this contribution, I suggest to broaden the concept of urban extractivism to address pressing challenges of urban transformations in the peripheries of Mexico City, particularly concerning urban infrastructure megaprojects and Indigenous socio-territorial movements that advocate for a more sustainable use of natural resources. Critical reflection on the extractivism of knowledge reveals the need for more collaborative research methods in urban geography and beyond

Territorial subjectivities. The missing link between political subjectivity and territorialization

Political subjectivity and territorialization often appear disconnected in recent debates. We propose a fresh approach based on Latin American scholarship to understand subjects and territories as relational: Subjects are (de)stabilized in processes of territorialization, while territories are (de)stabilized in processes of subject formation. We introduce the concept of territorial subjectivities and use examples from the literature to show how these emerge in Berlin, Buenos Aires, and Dresden. Placing an analytical focus on becoming rather than being, the contingency of territorial subjectivities is key to this novel conceptual link that supports a differentiated reading of socio-territorial struggles in diverse geographical contexts

Incommensurate magnetic ordering in Cu2Te2O5X2Cu_2 Te_2 O_5 X_2 (X=Cl,Br) studied by neutron diffraction

We present the results of the first neutron powder and single crystal diffraction studies of the coupled spin tetrahedra systems {\CuTeX} (X=Cl, Br). Incommensurate antiferromagnetic order with the propagation vectors {\bf{k}_{Cl}}\approx[0.150,0.422,\half], {\bf{k}_{Br}}\approx[0.158,0.354,\half] sets in below $T_{N}$=18 K for X=Cl and 11 K for X=Br. No simple collinear antiferromagnetic or ferromagnetic arrangements of moments within Cu${}^{2+}$ tetrahedra fit these observations. Fitting the diffraction data to more complex but physically reasonable models with multiple helices leads to a moment of 0.67(1)$\mu_B$/Cu${}^{2+}$ at 1.5 K for the Cl-compound. The reason for such a complex ground state may be geometrical frustration of the spins due to the intra- and inter-tetrahedral couplings having similar strengths. The magnetic moment in the Br- compound, calculated assuming it has the same magnetic structure as the Cl compound, is only 0.51(5)$\mu_B$/Cu${}^{2+}$ at 1.5 K. In neither compound has any evidence for a structural transition accompanying the magnetic ordering been found

Gemeinsam Karten lesen: kollektive Wissensproduktion in der Stadtforschung

Während in der heutigen Stadtforschung ausführlich über das Karten-Machen geschrieben wird, spielt das Karten-Lesen bei der kritischen Analyse kaum eine Rolle. Das Karten-Lesen selbst – gerade in einer Gruppe – ist jedoch ein zentraler Schritt im Prozess der (kollektiven) raumbezogenen Wissensproduktion. Am Beispiel des Workshops „Poner las cartas sobre la mesa“ (dt. „die Karten auf den Tisch legen“) in Mexiko-Stadt möchten wir diesen methodischen Ansatz im Umgang mit Karten diskutieren und weiter einsetzbar machen

Warum klassische Evaluation oftmals nicht ausreicht – eine Studie zur Ermittlung der Bedeutsamkeit Mentaler Modelle als Evaluationsmethode

Hohe Benutzertauglichkeit und Akzeptanz eines Webseitenservices sind nur dann gewährleistet, wenn diese auf die funktionalen Bedürfnisse, aber auch auf die strukturellen Vorstellungen ihrer Benutzer zugeschnitten sind. Im Kontext einer Webseite zur „Suche nach E-Learning-Produkten im Internet“ wurde untersucht, inwieweit die Kenntnis der Mentalen Modelle potenzieller Nutzer den Softwareentwicklungsprozess positiv beeinflussen kann. Dabei erlaubte die Erhebung Mentaler Modelle mit Hilfe der Struktur-Lege-Technik (SLT) als Evaluationsmethode einen Vergleich mit der tatsächlich entwickelten Webseite. Die Studie zeigte, dass trotz zuvor bereits durchgeführter, klassischer Evaluationen (Usability Tests, Anwendung von Heuristiken und Cognitive Walkthroughs) 40 Funktionsbereiche genannt wurden, die auf der tatsächlichen Webseite nicht vorgesehen oder umgesetzt sind. Daraus folgt, dass die Erhebung von Mentalen Modellen ebenfalls bereits vor dem Software-Entwicklungsprozess durchgeführt werden soll. (DIPF/Orig.

Adaptive Wissensvermittlung am Beispiel der eLearning-Umgebung "Psychopathology Taught Online" (PTO)

Der vorliegende Beitrag stellt das Projekt der eLearning-Umgebung „Psychopathology Taught Online“ (PTO) vor. PTO soll als ein zum bestehenden universitären Lehrangebot im Bereich Psychopathologie ergänzendes digitales Curriculum eingesetzt werden. Der inhaltliche Schwerpunkt liegt auf der Phänomenologie psychischer Störungen. Besonders hervorzuheben ist die zur Gewährleistung von inhaltlicher Adaptivität des Lernprogramms verwendete Methodik. Mittels robuster Nonmetrischer Multidimensionaler Skalierung (NMDS) können Wissenskarten des Lerners erstellt werden, welche speziell auf relationale Zusammenhänge der deklarativen Wissensinhalte sensitiv sind und diese in einem Raummodell darstellen. Auf der Basis des Vergleichs einer Lernerkarte mit einem Normmodell (durch Prokrustes-Transformation) können spezifische Wissensmängel detektiert werden. Dies erlaubt das Geben von automatisierten, individuell angepassten Lernempfehlungen. (DIPF/Orig.

How to Compare Specificity, Build Concepts, and Change Theory: A Creative Methodology to Grasp Urbanization Processes

In a range of comparative methods that have emerged in recent years, scholars were increasingly drawing on innovative approaches to engage with today's diverse and complex urban worlds. Yet few researchers to date—in the field of urban studies or in spatial disciplines in general—have focused on the design and implementation of comparative inquiry. With this article, I seek to contribute to these current debates by presenting the specific methodology developed in the framework of the research project Patterns and Pathways of Planetary Urbanization. The main questions are: How can the spatiality of large urban territories be empirically studied? How can urbanization processes be analyzed comparatively? To tackle these questions, I focus on our experiences of putting the comparative procedure to work, drawing on a complementary set of ethnographic, cartographic, and historiographic methods useful for a creative, transdisciplinary, and more collaborative study of urbanization. I conclude with a call for a broad discussion of methodology and its theoretical implications by emphasizing the intrinsic link between crafting new methods and the generation of comparative concepts

Incorporation of urban differences in Tokyo, Mexico City, and Los Angeles

Reinvestment and intensification are common processes in many urban areas across the world. These transformations are often analyzed with concepts such as ‘urban regeneration’, ‘urban renaissance’, or ‘gentrification’. However, in analyzing Shimokitazawa (Tokyo), Centro Histórico (Mexico City), and Downtown Los Angeles, we realized that these concepts do not fully grasp the qualitative changes of everyday life and the contradictory character of the urbanization processes we observed. They do not take into consideration the far-reaching effects of these processes, and particularly do not address the underlying key question: how is urban value produced? Therefore, we have chosen a different analytical entry point to these transformations, by focusing on the production, reproduction, and incorporation of the intrinsic qualities of the urban. We found Lefebvre’s concept of ‘urban differences’ and Williams’ concept of ‘incorporation’ particularly useful for analyzing our empirical results. In this contribution, we compare the ‘incorporation of urban differences’ in the three case study areas and offer this concept for further discussions and applications

Comparison of Cooling System Designs for an Exhaust Heat Recovery System Using an Organic Rankine Cycle on a Heavy Duty Truck

A complex simulation model of a heavy duty truck, including an Organic Rankine Cycle (ORC) based waste heat recovery system and a vehicle cooling system, was applied to determine the system fuel economy potential in a typical drive cycle. Measures to increase the system performance were investigated and a comparison between two different cooling system designs was derived. The base design, which was realized on a Mercedes-Benz Actros vehicle revealed a fuel efficiency benefit of 2.6%, while a more complicated design would generate 3.1%. Furthermore, fully transient simulation results were performed and are compared to steady state simulation results. It is shown that steady state simulation can produce comparable results if averaged road data are used as boundary conditions

Spin-state transition in LaCoO3: direct neutron spectroscopic evidence of excited magnetic states

A gradual spin-state transition occurs in LaCoO3 around T~80-120 K, whose detailed nature remains controversial. We studied this transition by means of inelastic neutron scattering (INS), and found that with increasing temperature an excitation at ~0.6 meV appears, whose intensity increases with temperature, following the bulk magnetization. Within a model including crystal field interaction and spin-orbit coupling we interpret this excitation as originating from a transition between thermally excited states located about 120 K above the ground state. We further discuss the nature of the magnetic excited state in terms of intermediate-spin (IS, S=1) vs. high-spin (HS, S=2) states. Since the g-factor obtained from the field dependence of the INS is g~3, the second interpretation looks more plausible.Comment: 10 pages, 4 figure