Placing the poor while keeping the rich in their place

A central objective of modern US housing policy is deconcentrating poverty through "housing mobility programs" that move poor families into middle class neighborhoods. Pursuing these policies too aggressively risks inducing middle class flight, but being too cautious squanders the opportunity to help more poor families. This paper presents a stylized dynamicoptimization model that captures this tension. With base-caseparameter values, cost considerations limit mobility programs before flight becomes excessive. However, for modest departures reflecting stronger flight tendencies and/or weaker destination neighborhoods, other outcomes emerge. In particular, we find state-dependence and multiple equilibria, including both de-populated and oversized outcomes. For certain sets of parameters there exists a Skiba point that separates initial conditions for which the optimal strategy leads to substantial flight and depopulation from those for which the optimal strategy retains or even expands the middle class population. These results suggest the value of estimating middle-class neighborhoods' "carrying capacity" for absorbing mobility program placements and further modeling of dynamic response.housing policy, multiple equilibria, negative externality, optimal control, segregation, separation, Skiba point

Eine Analyse von Food-Wertschöpfungsketten auf Basis internationaler Vergleichsdaten und Fallstudien

In der Schweiz zahlte der Verbraucher im Jahr 2015 für einen identisch gewichteten Warenkorb an Food-Produkten im Durchschnitt 45 Prozent mehr als in den vier Nachbarländern. Der grösste Preisunterschied existiert bei Fleischprodukten (+85%). Für den gesamten Konsumgüterwarenkorb ergibt sich ein Preisaufschlag von 29 Prozent. Nahrungs- und Genussmittel sind in der Schweiz also im Vergleich zu anderen Konsumgütern überproportional teuer. Im Vergleich mit Dienstleistungen (die in der Schweiz 72% teurer sind als in den Nachbarländern) gilt das Gegenteil. In der Agrarpolitik stellt sich vor dem Hintergrund der hohen Nahrungsmittelpreise die Frage, ob die preisliche Wettbewerbsfähigkeit der Schweizer Agrarmärkte verbessert werden kann. Die vorliegende Studie geht dieser Frage mit einer Analyse der inländischen Food-Wertschöpfungskette nach. Das Forschungsdesign wurde mit dem Ziel entwickelt, die Funktionsweise und Handelspraktiken von Schweizer Agrarmärkten hinsichtlich Marktkonzentrationen und -asymmetrien zu evaluieren und mögliche Zusammenhänge zwischen Marktstruktur und Marktergebnis (Konsumentenpreise) empirisch zu untersuchen

Lethal Carbon Monoxide Poisoning in Wood Pellet Storerooms—Two Cases and a Review of the Literature

The installation of wood pellet heating as a cost-effective and climatically neutral source of energy for private households has increased steadily in recent years. We report two deaths that occurred within the space of about a year in wood pellet storerooms of private households in German-speaking countries and were investigated by forensic medical teams. This is the first report of fatalities in this special context as is shown in the literature review. Both victims died of carbon monoxide (CO) poisoning; one of the victims was a woman who was 4 months pregnant. Measurements at the scene detected life-threatening CO concentrations (7500 ppm, >500 ppm), which were not significantly reduced after ventilation of the storerooms as required by regulations. We carried out a series of experiments in order to confirm CO production by wood pellets. Thirty kilograms of freshly produced pellets from two different manufacturers were stored for 16 days in airtight containers at 26°C with different relative humidities. CO concentrations between 3100 and 4700 ppm were measured in all containers. There were no notable differences between the wood pellet products or storage at different humidities. Emission of CO from wood pellets has already been described, but fatal accidents have previously been reported only in association with pellet transport on cargo ships or storage in silos. It is therefore a new finding that fatal accidents may also occur in the wood pellet storerooms of private households. We show that significant CO concentrations can build up even when these rooms are ventilated in accordance with the regulations and that such levels may cause the death of healthy persons, as described in the following. As the safety recommendations from the wood pellet industry are inadequate, we consider that further fatal accidents are likely to occur and recommend urgent revision of the safety regulation

Nonequilibrium control of thermal and mechanical changes in a levitated system

Fluctuation theorems are fundamental extensions of the second law of thermodynamics for small nonequilibrium systems. While work and heat are equally important forms of energy exchange, fluctuation relations have not been experimentally assessed for the generic situation of simultaneous mechanical and thermal changes. Thermal driving is indeed generally slow and more difficult to realize than mechanical driving. We here use feedback cooling techniques to implement fast and controlled temperature variations of an underdamped levitated microparticle that are one order of magnitude faster than the equilibration time. Combining mechanical and thermal control, we verify the validity of a fluctuation theorem that accounts for both contributions, well beyond the range of linear response theory. Our system allows the investigation of general far-from-equilibrium processes in microscopic systems that involve fast mechanical and thermal changes at the same time

Highly Enhanced Concentration and Stability of Reactive Ce^3+ on Doped CeO_2 Surface Revealed In Operando

Trivalent cerium ions in CeO_2 are the key active species in a wide range of catalytic and electro-catalytic reactions. We employed ambient pressure X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy to quantify simultaneously the concentration of the reactive Ce^3+ species on the surface and in the bulk of Sm-doped CeO_2(100) in hundreds of millitorr of H2–H2O gas mixtures. Under relatively oxidizing conditions, when the bulk cerium is almost entirely in the 4+ oxidation state, the surface concentration of the reduced Ce^3+ species can be over 180 times the bulk concentration. Furthermore, in stark contrast to the bulk, the surface’s 3+ oxidation state is also highly stable, with concentration almost independent of temperature and oxygen partial pressure. Our thermodynamic measurements reveal that the difference between the bulk and surface partial molar entropies plays a key role in this stabilization. The high concentration and stability of reactive surface Ce^3+ over wide ranges of temperature and oxygen partial pressure may be responsible for the high activity of doped ceria in many pollution-control and energy-conversion reactions, under conditions at which Ce^3+ is not abundant in the bulk

Measuring individual overpotentials in an operating solid-oxide electrochemical cell

We use photo-electrons as a non-contact probe to measure local electrical potentials in a solid-oxide electrochemical cell. We characterize the cell in operando at near-ambient pressure using spatially-resolved X-ray photoemission spectroscopy. The overpotentials at the interfaces between the Ni and Pt electrodes and the yttria-stabilized zirconia (YSZ) electrolyte are directly measured. The method is validated using electrochemical impedance spectroscopy. Using the overpotentials, which characterize the cell's inefficiencies, we compare without ambiguity the electro-catalytic efficiencies of Ni and Pt, finding that on Ni H_2O splitting proceeds more rapidly than H2 oxidation, while on Pt, H2 oxidation proceeds more rapidly than H2O splitting.Comment: corrected; Phys. Chem. Chem. Phys., 201

Characterization of a Dipartite Iron Uptake System from Uropathogenic \u3ci\u3eEscherichia coli\u3c/i\u3e Strain

In the uropathogenic Escherichia coli strain F11, in silico genome analysis revealed the dicistronic iron uptake operon fetMP, which is under iron-regulated control mediated by the Fur regulator. The expression of fetMP in a mutant strain lacking known iron uptake systems improved growth under iron depletion and increased cellular iron accumulation. FetM is a member of the iron/lead transporter superfamily and is essential for iron uptake by the Fet system. FetP is a periplasmic protein that enhanced iron uptake by FetM. Recombinant FetP bound Cu(II) and the iron analog Mn(II) at distinct sites. The crystal structure of the FetP dimer reveals a copper site in each FetP subunit that adopts two conformations: CuA with a tetrahedral geometry composed of His44, Met90, His97, and His127, and CuB, a second degenerate octahedral geometry with the addition of Glu46. The copper ions of each site occupy distinct positions and are separated by 1.3A . Nearby, a putative additional Cu(I) binding site is proposed as an electron source that may function with CuA/CuB displacement to reduce Fe(III) for transport by FetM. Together, these data indicate that FetMP is an additional iron uptake system composed of a putative iron permease and an iron-scavenging and potentially iron-reducing periplasmic protein

Smart Chest X-ray Worklist Prioritization using Artificial Intelligence: A Clinical Workflow Simulation

The aim is to evaluate whether smart worklist prioritization by artificial intelligence (AI) can optimize the radiology workflow and reduce report turnaround times (RTAT) for critical findings in chest radiographs (CXRs). Furthermore, we investigate a method to counteract the effect of false negative predictions by AI -- resulting in an extremely and dangerously long RTAT, as CXRs are sorted to the end of the worklist. We developed a simulation framework that models the current workflow at a university hospital by incorporating hospital specific CXR generation rates, reporting rates and pathology distribution. Using this, we simulated the standard worklist processing "first-in, first-out" (FIFO) and compared it with a worklist prioritization based on urgency. Examination prioritization was performed by the AI, classifying eight different pathological findings ranked in descending order of urgency: pneumothorax, pleural effusion, infiltrate, congestion, atelectasis, cardiomegaly, mass and foreign object. Furthermore, we introduced an upper limit for the maximum waiting time, after which the highest urgency is assigned to the examination. The average RTAT for all critical findings was significantly reduced in all Prioritization-simulations compared to the FIFO-simulation (e.g. pneumothorax: 35.6 min vs. 80.1 min; p $<0.0001$), while the maximum RTAT for most findings increased at the same time (e.g. pneumothorax: 1293 min vs 890 min; p $<0.0001$). Our "upper limit" substantially reduced the maximum RTAT all classes (e.g. pneumothorax: 979 min vs. 1293 min / 1178 min; p $<0.0001$). Our simulations demonstrate that smart worklist prioritization by AI can reduce the average RTAT for critical findings in CXRs while maintaining a small maximum RTAT as FIFO