Age determination of Petra's engineered landscape – optically stimulated luminescence (OSL) and radiocarbon ages of runoff terrace systems in the Eastern Highlands of Jordan

The unfavourable mountainous environment of the Petra region in southern Jordan was modified by ancient engineers to supply the Nabataean/Roman city of Petra with food and water. The area was reclaimed by installing extended runoff terrace systems and hydraulic structures. The agricultural terrace systems have so far been dated based on surface pottery, and the chronology of the systems is under debate. In this study, optically stimulated luminescence (OSL) and radiocarbon dating techniques were successfully applied to date these terrace systems. Samples were taken from the fills of agricultural terraces and underneath their walls to determine the chronology of the construction, use and abandonment of the agricultural terraces. The results suggest that runoff farming in the Petra region started around the beginning of the Common Era, and construction, use and maintenance lasted at least until 800 AD.     

Optical dating of alluvial deposits at the orogenic front of the andean precordillera (Mendoza,Argentina)

Well constrained numerical ages of alluvial fan sediments are key to understanding the chronology of alluvial episodes and tectonic activity at the front of the Andean Precordillera. We tested the application of radiocarbon and optically stimulated luminescence (OSL) dating in the distal part of an alluvial fan five kilometers north of Mendoza. For OSL dating a large number of aliquots (n > 70) — each composed of ∼50 quartz grains — were measured in order to obtain reliable burial ages despite scattered dose distributions. Owing to a feldspar contamination in all samples, an infrared stimulation was inserted before each OSL measurement, which reduced the feldspar OSL signal successfully. By using the minimum age model we obtained stratigraphically consistent burial ages of alluvial deposits in a depth profile. The uppermost ∼1 m of sediment is composed of debris flow deposits buried 770±76 years ago. Three plant remnants used for radiocarbon dating from the same layer, however, yielded ages younger than 350 years, which are interpreted to underestimate the depositional age. Underneath the debris flow, a major unconformity cuts a series of distal alluvial fan sediments with interstratified floodplain deposits, which are composed of sandy and calciterich silt layers, respectively. Three samples from this unit which were distributed over one meter of sediment thickness yielded statistically concordant OSL ages of 12.3±1.2 ka, 12.3±1.2 ka, and 11.7±1.1 ka. The deposition of these sediments during the latest Pleistocene coincides with a phase of cool and humid climate, which occurred before the alluvial fan propagated farther into the foreland. The overlying debris flow sediments are associated with alluvial fan incision during the arid Late Holocene.     

Leitbilder und Handlungsstrategien für die Raumentwicklung in Deutschland Entwicklungs-, Umsetzungs- und Fortschreibungsprozess der Bund-L?nder-Strategie für St?dte und Regionen

Die Ministerkonferenz für Raumordnung stellte im Mai 2010 fest, dass sich die „Leitbilder und Handlungsstrategien für die Raumentwicklung in Deutschland“ (2006) bew?hrt haben und bei der Gestaltung der r?umlichen Entwicklung umgesetzt werden. Um die Leitbilder den sich ver?ndernden wirtschaftlichen, sozialen und naturr?umlichen Rahmenbedingungen anzupassen und die Erkenntnisse aus dem bisherigen Diskussions- und Umsetzungsprozess in Politik und Praxis einzubeziehen, sind sie zu erg?nzen und weiterzuentwickeln. Im Mittelpunkt der Fortschreibung werden die Themen „Partnerschaften und Strategien für Stadtregionen und l?ndliche R?ume“, „Mobilit?t und Logistik“ sowie „Klimaschutz und Energieversorgung“ stehen.     

Knowledge Spillovers and Total Factor Productivity: Evidence Using a Spatial Panel Data Model

This article investigates the impact of knowledge capital stocks on total factor productivity (TFP) through the lens of the knowledge capital model proposed by Griliches (1979) , augmented with a spatially discounted cross-region knowledge spillover pool variable. The objective is to shift attention from firms and industries to regions and to estimate the impact of cross-region knowledge spillovers on TFP in Europe. The dependent variable is the region-level TFP, measured in terms of the superlative TFP index suggested by Caves, Christensen, and Diewert (1982) . This index describes how efficiently each region transforms physical capital and labor into output. The explanatory variables are internal and out-of-region stocks of knowledge, the latter capturing the contribution of cross-region knowledge spillovers. We construct patent stocks to proxy annual regional knowledge capital stocks for N =203 regions during 1997–2002. In estimating the effects, we implement a spatial panel data model that controls for spatial autocorrelation as well as individual heterogeneity across regions. The findings provide a fairly remarkable confirmation of the role of knowledge capital contributing to productivity differences among regions and add an important spatial dimension to discussions in the literature by showing that productivity effects of knowledge spillovers increase with geographic proximity.     

A Methodology for Neural Spatial Interaction Modeling

This paper attempts to develop a mathematically rigid and unified framework for neural spatial interaction modeling. Families of classical neural network models, but also less classical ones such as product unit neural network ones are considered for the cases of unconstrained and singly constrained spatial interaction flows. Current practice appears to suffer from least squares and normality assumptions that ignore the true integer nature of the flows and approximate a discrete‐valued process by an almost certainly misrepresentative continuous distribution. To overcome this deficiency we suggest a more suitable estimation approach, maximum likelihood estimation under more realistic distributional assumptions of Poisson processes, and utilize a global search procedure, called Alopex, to solve the maximum likelihood estimation problem. To identify the transition from underfitting to overfitting we split the data into training, internal validation, and test sets. The bootstrapping pairs approach with replacement is adopted to combine the purity of data splitting with the power of a resampling procedure to overcome the generally neglected issue of fixed data splitting and the problem of scarce data. In addition, the approach has power to provide a better statistical picture of the prediction variability. Finally, a benchmark comparison against the classical gravity models illustrates the superiority of both, the unconstrained and the origin constrained neural network model versions in terms of generalization performance measured by Kullback and Leibler's information criterion.     

Housing Choice in a Regulated Market: A Nested Multinomial Logit Analysis

The paper integrates several important elements of the institutionalized and regulated nature of the housing market and analyzes the relationship between household type and housing choice in Vienna within a nested multinomial logit framework. In particular, the concept of household specific choice sets is used to account for institutional, informational and income-based constraints of the choice process. Government subsidies (such as housing and rent allowances, non-interest-bearing state loans) are explicitly taken into account in the definition of variables. Housing choice is considered in three stages: the choice of a dwelling unit given dwelling type and residential zone, the choice of a dwelling type given residential zone, and the marginal choice of a residential zone. The coefficients are derived by means of a sequential ML-procedure. The empirical results clearly indicate that demographic variables have significant impacts on housing choice behavior. Income as a single explanatory variable as well as its interacting with size measures and the quality of the house are found to be important criteria for dwelling unit choice, as housing cost variables for dwelling type choice behavior. The dwelling unit and dwelling type choice submodels fit reasonably well, whereas the residential zone model is less successful.     

Gedanken zum namen Himālaya

Ohne ZusammenfassungWilhelm Brandenstein zum 60. Geburtstag gewidmet.