Non-linear relationship between bulk δC and percent maize in carbonized cooking residues and the potential of false-negatives in detecting maize

Bulk δ¹³C values on charred cooking residues adhering to pottery sherd interior surfaces have been used as a source of information on the histories of maize in various locations in the western hemisphere. This approach is based on an assumption of a linear relationship between the percent maize in the resource mix cooked in a pot and δ¹³C. Previous experiments suggest that this relationship is non-linear, and maize may not be identified from bulk δ¹³C values even when it contributed substantially to the resource mix. A second round of experiments, presented here, indicates that the mobilization of carbon from maize and C₃ resources over time is the critical variable in residue formation and the resulting bulk δ¹³C value. This is influenced by the form of maize being cooked.     

Employment Deconcentration: A New Perspective on America's Postwar Urban Evolution

In this study we show that during the postwar era the United States experienced a decline in the share of urban employment accounted for by the relatively dense metropolitan areas and a corresponding rise in the share of relatively less dense ones. This trend, which we call employment deconcentration , is distinct from the other well–known regional trend, namely, the postwar movement of jobs and people from the frostbelt to the sunbelt. We also show that deconcentration has been accompanied by a similar trend within metropolitan areas, wherein employment share of the more dense sections of MSAs has declined and that of the less dense sections risen. We provide a general equilibrium model with density–driven congestion costs to suggest an explanation for employment deconcentration.     

Fl?chenmonitoring in der Regional- und Bauleitplanung Neue M?glichkeiten durch die Analyse von Satellitenbildern

Deutschland hat ein umfassendes und in der Praxis bew?hrtes Planungssystem einschlie?lich integrierter Umweltprüfung, das auch für zus?tzliche bzw. erweiterte Prüfinstrumente günstige Voraussetzungen bietet. Das Fl?chenmonitoring in der Regionalplanung, aber auch für die St?dte und Gemeinden in der vorbereitenden Bauleitplanung kann mit Hilfe einer gezielten Ver?nderungsanalyse der Landbedeckung als ein Baustein eines umfassenden Monitoringsystems und zur Unterstützung des Nachhaltigkeitsprinzips verstanden werden. Da jedoch insbesondere für einen l?ngeren Beobachtungszeitraum kaum bzw. keine (digitalen) Informationen über die Landbedeckung existieren, stellt die Auswertung von Satellitendaten einen L?sungsansatz dar. Inwiefern sich die semiautomatische Analyse von Satellitenbildern als ein geeignetes Instrument zur Bewertung und Ver?nderung der Nutzung eines Landkreises eignet bzw. worin Analyseprobleme sowie M?glichkeiten und Grenzen der Anwendung in der Regionalplanung existieren, soll im folgenden Beitrag am Beispiel des Landkreises Osnabrück thematisiert werden.     

CONVERGENCE AND THE U.S. STATES: A TIME-SERIES ANALYSIS*

ABSTRACT. After decades of apparent convergence, state and regional per capita earnings diverged between 1978 and 1988. A central tenet of the convergence hypothesis is that shocks to relative state and regional earnings, such as those of the 1978 to 1988 period, are transitory. We find evidence for convergence for the U.S. states and regions during the 1929 to 1990 period after allowing for a break in the rate at which the various states and regions were converging in 1946. An important finding of this research is that the US. states and regions achieved per capita earnings convergence by 1946.