121 research outputs found
The China miracle in a technological and socio-political frameworkâThe role of institutions
Chinaâs economy has grown at an average annual rate of around 9.5% in the past four decades, which is often hailed as the China Miracle. This paper proposes a new theoretical model to analyse the causes of Chinaâs phenomenal growth in a technological and socio-political framework. In our new framework, the contemporary technology (T) determines what an economy can achieve; the objective (O) of the society has a fundamental impact on its economic growth; the performance (P) in implementing the social objective largely determines the growth rate of the economy; and the stability (S) of the society determines the sustainability of the economic growth. Chinaâs institutions have played key roles in the TOPS framework to initiate and sustain Chinaâs rapid growth in the past four decades. Socio-political changes caused by economic growth might affect the capacity of these institutions to promote economic growth in future
Metal halide perovskites for energy applications
Exploring prospective materials for energy production and storage is one of the biggest challenges of this century. Solar energy is one of the most important renewable energy resources, due to its wide availability and low environmental impact. Metal halide perovskites have emerged as a class of semiconductor materials with unique properties, including tunable bandgap, high absorption coefficient, broad absorption spectrum, high charge carrier mobility and long charge diffusion lengths, which enable a broad range of photovoltaic and optoelectronic applications. Since the first embodiment of perovskite solar cells showing a power conversion efficiency of 3.8%, the device performance has been boosted up to a certified 22.1% within a few years. In this Perspective, we discuss differing forms of perovskite materials produced via various deposition procedures. We focus on their energy-related applications and discuss current challenges and possible solutions, with the aim of stimulating potential new applications
Wages in high-tech start-ups - do academic spin-offs pay a wage premium?
Due to their origin from universities, academic spinâoffs operate at the forefront of the
technological development. Therefore, spinâoffs exhibit a skillâbiased labour demand, i.e. spinâoffs
have a high demand for employees with cutting edge knowledge and technical skills. In order to accommodate
this demand, spinâoffs may have to pay a relative wage premium compared to other
highâtech startâups. However, neither a comprehensive theoretical assessment nor the empirical
literature on wages in startâups unambiguously predicts the existence and the direction of wage differentials
between spinâoffs and nonâspinâoffs. This paper addresses this research gap and examines
empirically whether or not spinâoffs pay their employees a wage premium. Using a unique linked
employerâemployee data set of German highâtech startâups, we estimate Mincerâtype wage regressions
applying the HausmanâTaylor panel estimator. Our results show that spinâoffs do not pay a
wage premium in general. However, a notable exception from this general result is that spinâoffs that
commercialise new scientific results or methods provide higher wages to employees with linkages to
the university sector â either as university graduates or as student workers
Tooth transposition prevalence and type among sub-Saharan Africans
Objectives: Although rare, tooth transpositionâan exchange in location of two teethâis a frequent topic of study. Clinical and, to a much lesser extent, dental anthropological research have focused predominantly on prevalence (0.03%â0.74% in several world populations) and case studies, albeit on a restricted spatiotemporal scale. Many regions have received little attention, including subâSaharan Africa, while premodern data are few. Here, the aim is to supplement both fields of dental research by reviewing previous publications, and newly reporting transposition rates, types, and coâoccurring abnormalities in timeâsuccessive samples across the subcontinent.
Methods: Dental data in 51 subâSaharan samples (>2500 individuals) dating >10â000âBC to 20th century were recorded. Of these, 36 are of modern and 15 premodern age, comprising males and females âĽ12âyears of age. Transposition presence, quadrant, and type were tabulated, cases described, and prevalence presented. In the latter case, Poisson 95% confidence intervals were calculated to better discern true population rates at various geographic levels.
Results: Overall, six of 1886 modern individuals (0.32%) and one of premodern age evidence Mx.C.P1, an exchange of the maxillary canine and first premolar. Various associated dental abnormalities are also evident, including retained deciduous teeth, reduced permanent crowns, and agenesis.
Conclusions: This study provides additional insight into the geographic distribution, features, and time depth of transposition, along with hints supporting a genetic etiology and, potentially, some indications of diachronic change from an initial Mx.C.P1 to several types more recently based on premodern evidence. It is of clinical concern today, but is not just a modern anomaly
Restriction in lateral bending range of motion, lumbar lordosis, and hamstring flexibility predicts the development of low back pain: a systematic review of prospective cohort studies
Asynchronous vegetation phenology enhances winter body condition of a large mobile herbivore
Uncertainty and investment dynamics
This paper shows that, with (partial) irreversibility, higher uncertainty reduces the impact effect of demand shocks on investment. Uncertainty increases real option values making firms more cautious when investing or disinvesting. This is confirmed both numerically for a model with a rich mix of adjustment costs, time-varying uncertainty, and aggregation over investment decisions and time, and also empirically for a panel of manufacturing firms. These cautionary effects of uncertainty are large - going from the lower quartile to the upper quartile of the uncertainty distribution typically halves the first year investment response to demand shocks. This implies the responsiveness of firms to any given policy stimulus may be much lower in periods of high uncertainty, such as after major shocks like OPEC I and 9/11
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