827 research outputs found

    Tentative identification of the apoproteins of iron-sulfur centers of Photosystem I

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    AbstractA newly purified Photosystem (PS) I particle is described, with still active iron-sulfur acceptors: A, B and X. Apart from the apoprotein of P700, 3 other main polypeptides of this particle are located at 20, 17 and 10 kDa, and two minor ones are detectable at 16.5 and 8 kDa. Both in vivo 35S labeling and carboxymethylation with iodo[14C]acetate show that most of the cysteine residues are located in the 8-kDa band. The amino acid composition of this band reveals important common features with small iron-sulfur proteins of the ferredoxin type

    State incentives for innovation, star scientists and jobs: Evidence from biotech

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    We evaluate the effects of state-provided financial incentives for biotech companies, which are part of a growing trend of placed-based policies designed to spur innovation clusters. We estimate that the adoption of subsidies for biotech employers by a state raises the number of star biotech scientists in that state by about 15 percent over a three-year period. A 10 percent decline in the user cost of capital induced by an increase in R&D tax incentives raises the number of stars by 22 percent. Most of the gains are due to the relocation of star scientists to adopting states, with limited effect on the productivity of incumbent scientists already in the state. The gains are concentrated among private sector inventors. We uncover little effect of subsidies on academic researchers, consistent with the fact that their incentives are unaffected. Our estimates indicate that the effect on overall employment in the biotech sector is of comparable magnitude to that of star scientists. Consistent with a model where workers are fairly mobile across states, we find limited effects on salaries in the industry. We uncover large effects on employment in the nontraded sector due to a sizable multiplier effect, with the largest impact on employment in construction and retail. Finally, we find mixed evidence of a displacement effect on states that are geographically close, or states that are economically close as measured by migration flows

    Modelling Hierarchy and Specialization of a System of Cities from an Evolutionary Perspective on Firms' Interactions

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    Despite their great diversity, most systems of cities show remarkably similar patterns when comparing the size distribution and the economic specialization of their constitutive cities. The universality of these patterns sparked the interest of geographers, economists and physicists. However, until now, no economic model has relied on a micro-based and evolutionary approach to reproduce these regularities. In this chapter, we intend to fill this gap by proposing a model where the micro dynamics of localized firms generate the two macro regularities of size distribution and economic specialization. The model is based on boundedly rational firms’ competition and path dependent innovation. We discuss the possible emergence of macro properties from these micro behaviors of firms

    Vitamin D and Calcium Supplementation Accelerates Randall's Plaque Formation in a Murine Model

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    Most kidney stones are made of calcium oxalate crystals. Randall\u27s plaque, an apatite deposit at the tip of the renal papilla, is considered to at the origin of these stones. Hypercalciuria may promote Randall\u27s plaque formation and growth. We analyzed whether long-term exposure of Abcc6 mice (a murine model of Randall\u27s plaque) to vitamin D supplementation, with or without a calcium-rich diet, would accelerate the formation of Randall\u27s plaque. Eight groups of mice (including Abcc6 and wild type) received vitamin D alone (100,000 UI/kg every 2 weeks), a calcium-enriched diet alone (calcium gluconate 2 g/L in drinking water), both vitamin D supplementation and a calcium-rich diet, or a standard diet (controls) for 6 months. Kidney calcifications were assessed by 3-dimensional microcomputed tomography, μ-Fourier transform infrared spectroscopy, field emission-scanning electron microscopy, transmission electron microscopy, and Yasue staining. At 6 months, Abcc6 mice exposed to vitamin D and calcium supplementation developed massive Randall\u27s plaque when compared with control Abcc6 mice (P < 0.01). Wild-type animals did not develop significant calcifications when exposed to vitamin D. Combined administration of vitamin D and calcium significantly accelerates Randall\u27s plaque formation in a murine model. This original model raises concerns about the cumulative risk of vitamin D supplementation and calcium intakes in Randall\u27s plaque formation

    Cultural and creative industries and regional diversification:Does size matter?

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    This paper aims at analysing how the presence of workers employed in cultural and creative industries (CCIs) is related to regional specialized diversification. From a theoretical perspective, CCIs drive economic development and local innovative capacity by facilitating processes of cross-fertilization of ideas. This study estimates an entry model analysing the ability of Italian provinces to successfully create new sectoral specializations. The results indicate that the relationship between the share of employees in CCIs and the probability of creating new sectoral specializations is non-linear, highlighting the need for CCIs-led policies to achieve a certain level of critical mass to be successful

    Government institutions and the dynamics of urban growth in China

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    Economic growth in China in recent decades has largely rested on the dynamism of its cities. High economic growth has coincided with measures aimed at improving the efficiency of local governments and with a mounting political drive to curb corruption. Yet the connection between government institutions and urban growth in China remains poorly understood. This paper is the first to look into the link between government efficiency and corruption, on the one hand, and urban growth in China, on the other hand and to assess what is the role of institutions relative to more traditional factors for economic growth in Chinese cities. Using panel data for 283 cities over the period between 2003 and 2014, the results show that the urban growth in China is a consequence of a combination of favorable human capital, innovation, density, local conditions, foreign direct investment, and city-level government institutions. Both government quality—especially for those cities with the best governments—and the fight against corruption at the city level have a direct effect on urban growth. Measures to tackle corruption at the provincial level matter in a more indirect way, by raising or lowering the returns of other growth-inducing factors
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