Bias correction in a dynamic panel data model of economic growth: The African dummy re-examined

The discrepancy between the observed and expected growth rates of African economies in cross-country or panel growth regressions is often summarised in a significant African dummy. However, the existence of this dummy may be an artifact of the panel data techniques used. The standard LSDV (least squares dummy variable) method produces a large bias in the estimate of the coefficient on the lagged dependent variable, which could generate the observed African dummy. The lagged dependent variable in a growth model is used to calculate the cross-country rate of convergence. If, however, the convergence rate is overestimated, then the Africa dummy would result due to the clustering of African economies at the lower end of the world cross-country income distribution. Correcting for the bias - using Kiviet’s (1995) algorithm - allows a fresh look at the apparent systematic underperformance of African countries relative to their growth predictions. Little evidence remains of such underperformance by African economies once the relevant bias in the dynamic panel has been accounted for.growth regressions, dynamic panels, African dummy

Household Formation, Poverty and Unemployment – The Case of Rural Households in South Africa

The paper examines household formation and composition decisions within the context of risk reduction and risk mitigation strategies of the poor in South Africa. A multi-level heckprobit estimator is employed in order to capture the influence of various factors at the individual, household and regional level, and we focus on the implications of the presence of pensioners and the unemployment on household composition and structure. Results are consistent with earlier findings that pensions are a key insurance mechanism for cushioning younger household members against adverse labour market conditions in rural South Africa. Hence they explain the propensity by household members to postpone formation of new independent household in order to continue living in multigenerational households.households, poverty, unemployment, rural South Africa

Evaluating the decisional balance construct of the Transtheoretical Model: are two dimensions of pros and cons really enough?

Objectives: The Transtheoretical Model of behavior change (TTM) postulates that behavior change is a process involving progress through five distinct stages of change (SOC). One of the key components for progress to a later stage is decisional balance (pros and cons of changing to the target behavior). The goal of the present study is to test the two dimensions of decisional balance as postulated in the TTM in the context of exercising behavior. Methods: The analyses are based on data from an online survey of 266 freshman students at the University of Zurich; participants self-reported their frequency of exercising and their weighing of the importance of 49 pros and cons of exercising. Results: The results indicate that a two-dimensional solution of decisional balance is insufficient. The analysis of pros and cons of exercising yielded a seven-factor solution with in part different progressions through the SOC. Conclusions: With the subdivision into different pros and cons, intervention programs can be developed that better match the needs of participants in terms of fostering and decreasing the most important pros and cons of exercisin

Ermittlung von Struktur-Reaktivitätsbeziehungen in CeO2-basierten Katalysatoren für die Selektive Katalytische Tieftemperatur-NH3-Reduktion von NOx: Einfluss von dreiwertigen Dotierungsionen auf die Reaktivität von Ceroxiden

Die vorliegende Dissertation beschäftigt sich mit dem Einfluss von dreiwertigen Dotierungselementen auf die katalytische Aktivität von Ceroxiden in der NH3-SCR von NOx mit und ohne V-Imprägnierung. Als Dotierungselemente wurden Fe3+, Y3+, Co3+, Sb3+ und Bi3+ in unterschiedlicher Konzentration gewählt. Die so entstandenen Mischoxide und festen Lösungen des Typs Ce(1-x)MxO(2-d) wurden katalytischer Testung unterworfen und umfangreich charakterisiert. Um die Struktur der Katalysatoren unter Reaktionsbedingungen zu verstehen, wurden operando DRIFTS, EPR und in situ XANES angewandt

Nb-modified Ce/Ti oxide catalyst for the selective catalytic reduction of NO with NH3 at low temperature

Recently, great attention has been paid to Ceria-based materials for selective catalytic reduction (SCR) with NH3 owing to their unique redox, oxygen storage, and acid-base properties. Two series of bimetallic catalysts issued from Titania modified by Ce and Nb were prepared by the one-step sol-gel method (SG) and by the sol-gel route followed by impregnation (WI). The resulting core-shell and bulk catalysts were tested in NH3-SCR of NOx. The impregnated Nb5/Ce40/Ti100 (WI) catalyst displayed 95% NOx conversion at 200 °C (GHSV = 60,000 mL·g−1·h−1, 1000 ppm NOx, 1000 ppm NH3, 5% O2/He) without forming N2O. The catalysts were characterized by various methods including ICP-OES, N2-physisorption, XRD, Raman, NH3-TPD, DRIFTS, XPS, and H2-TPR. The results showed that the introduction of Nb decreases the surface area and strengthens the surface acidity. This behavior can be explained by the strong interaction between Ceria and Titania which generates Ce-O-Ti units, as well as a high concentration of amorphous or highly dispersed Niobia. This should be the reason for the excellent performance of the catalyst prepared by the sol-gel method followed by impregnation. Furthermore, Nb5/Ce40/Ti100 (WI) has the largest NH3 adsorption capacity, which is helpful to promote the NH3-SCR reaction. The long-term stability and the effect of H2O on the catalysts were also evaluated

A Code of Conduct for Marine Carbon Dioxide Removal Research

Given the clear need to inform societal decision-making on the role marine Carbon Dioxide Removal (mCDR) can play in solving the climate crisis, it is imperative that researchers begin to answer questions about its effectiveness and impacts. Yet overly hasty deployment of new ocean-based climate interventions risks harm to communities and ecosystems and could jeopardize public perception of the field as a whole. In addition, the harms, risks and benefits of mCDR efforts are unlikely to be evenly distributed. Unabated, climate change could have a devastating impact on global ecosystems and human populations, and the impacts of mCDR should be contemplated in this context. This Code of Conduct exclusively applies to mCDR research and does not attempt to put any affiliated risk in the context of the risk of delaying climate action. Its purpose is to ensure that the impacts of mCDR research activities themselves are adequately understood and accounted for as they progress. It provides a roadmap of processes, procedures, and activities that project leads should follow to ensure that decisions regarding whether, when, where, and how to conduct mCDR research are informed by relevant ethical, scientific, economic, environmental, and regulatory considerations

The impact of basal ganglia lesions on sensorimotor synchronization, spontaneous motor tempo, and the detection of tempo changes

a b s t r a c t The basal ganglia (BG) are part of extensive subcortico-cortical circuits that are involved in a variety of motor and non-motor cognitive functions. Accumulating evidence suggests that one specific function that engages the BG and associated cortico-striato-thalamo-cortical circuitry is temporal processing, i.e., the mechanisms that underlie the encoding, decoding and evaluation of temporal relations or temporal structure. In the current study we investigated the interplay of two processes that require precise representations of temporal structure, namely the perception of an auditory pacing signal and manual motor production by means of finger tapping in a sensorimotor synchronization task. Patients with focal lesions of the BG and healthy control participants were asked to align finger taps to tone sequences that either did or did not contain a tempo acceleration or tempo deceleration at a predefined position, and to continue tapping at the final tempo after the pacing sequence had ceased. Performance in this adaptive synchronization-continuation paradigm differed between the two groups. Selective damage to the BG affected the abilities to detect tempo changes and to perform attention-dependent error correction, particularly in response to tempo decelerations. An additional assessment of preferred spontaneous, i.e., unpaced but regular, production rates yielded more heterogeneous results in the patient group. Together these findings provide evidence for less efficient processing in the perception and the production of temporal structure in patients with focal BG lesions. The results also support the functional role of the BG system in attention-dependent temporal processing