IPOs cycle and investment in high-tech industries

This paper analyses the effects of the Initial Public Offering (IPO) market on real investment decisions in emerging industries. We first propose a model of IPO timing based on divergence of opinion among investors and short-sale constraints. Using a real option approach, we show that firms are more likely to go public when the ratio of overvaluation over profits is high, that is after stock market run-ups. Because initial returns increase with the demand from optimistic investors at the time of the offer, the model provides an explanation for the observed positive causality between average initial returns and IPO volume. Second, we discuss the possibility of real overinvestment in high-tech industries. We claim that investing in the industry gives agents an option to sell the project on the stock market at an overvalued price enabling then the financing of positive NPV projects which would not be undertaken otherwise. It is shown that the IPO market can however also lead to overinvestment in new industries. Finally, we present some econometric results supporting the idea that funds committed to the financing of high-tech industries may respond positively to optimistic stock market valuations

Effects of agricultural commercialization on land tenure, household resource allocation, and nutrition in the Philippines:

Agriculture Economic aspects Philippines., Produce trade Philippines., Land tenure Philippines., Households Philippines., Nutrition Philippines.,

Some aspects of electronic topological transition in 2D system on a square lattice. Excitonic ordered states

We study the ordered "excitonic" states which develop around the quantum critical point (QCP) associated with the electronic topological transition (ETT) in a 2D electron system on a square lattice. We consider the case of hopping beyond nearest neighbors when ETT has an unusual character. We show that the amplitude of the order parameter (OP) and of the gap in the electron spectrum increase with increasing the distance from the QCP, \delta_c - \delta, where \delta = 1-n and "n" is an electron concentration. Such a behavior is different from the ordinary case when OP and the gap decrease when going away from the point which is a motor for instability. The gap opens at "hot spots" and extends untill the saddle points (SP) whatever is the doping concentration. The spectrum gets a characteristic flat shape as a result of hybrydization effect in the vicinity of two different SP's. The shape of the spectrum and the angle dependence of the gap have a striking similarity with the features observed in the normal state of the underdoped high-T$_c$ cuprates. We discuss also details about the phase diagram and the behaviour of the density of states.Comment: 15 pages, 14 EPS figures included, EPJ style included, added references, changed conten

Various ordered states in a 2D interacting electron system close to an electronic topological transition

We consider a 2D electron system on a square lattice with hopping beyond nearest neighbors. The existence of the quantum critical point associated with an electronic topological transition in the noninteracting system results in density wave (DW) and high temperature d-wave superconducting (dSC) instabilities in the presence of an exchange interaction J. We analyse different DW ordering such as isotropic Spin DW (SDW), d-wave SDW, isotropic Charge DW (CDW) and d-wave CDW. The coexistence of dSC and SDW orders leads necessary to the existence of a third order which is a pi triplet superconducting (PTS) order. A new phase diagram with a mixed phase of SDW, dSC and PTS order is found. The theory is applied to high-Tc cuprates.Comment: 2 pages, 1 figure, submitted to LT22 (Physica B

Effective action for the Kondo lattice model. New approach for S=1/2

In the partition function of the Kondo lattice, spin matrices are exactly replaced by bilinear combinations of Fermi operators with the purely imaginary chemical potential lambda=-i.pi.T/2 (Popov representation). This new representation of spin operators allows one to introduce new Green's functions with Matsubara frequencies 2.pi.T(n+1/4) for S=1/2. A simple temperature diagram technique is constructed with the path integral method. This technique is standard and does not contain the complicated combinatoric rules characteristic of most of the known variants of the diagram techniques for spin systems. The effective action for the almost antiferromagnetic Kondo lattice is derived.Comment: 7 pages, Proceedings of SCES98/Paris; one reference adde

Integrated economic modeling of global and regional micronutrient security:

In this paper, we examine the implications of alternative country-specific scenarios for biofortification on the reduction of micronutrient deficiency prevalence in under-fives. The scenarios are implemented within a long-term projections model of agriculture production and consumption, given the timeframe needed to develop and implement biofortification of crops and the need to account for changing diets over time. The effectiveness of the various biofortification strategies is largely determined by the evolution of regional dietary patterns over time, which show continued reliance on staple food crops among the poor. It suggests that cereal grain-focused biofortification is likely to be most effective in South Asia, while targeting roots and tubers is most effective in Sub-Saharan Africa.Biofortification, Micronutrients, Economic models,

Does Competition Promote Productivity Gains? An Analysis by Sector in OECD Countries

This paper analyses to what extent differences in competition intensity (assessed through estimated markups) between economic sectors explain international differences in hourly labour productivity gains at the sector level in a set of OECD countries. Results indicate the presence of a non-linear relationship between competition and labour productivity gains. Increased competition would benefit productivity growth in low-competition sectors, but would be detrimental above a certain level. This negative effect seems however fragile as it is no more significant when the sample is restricted to the most competitive sectors. Besides, in the manufacturing sectors characterized by relatively high competition and sunk costsmore intense competition would slow productivity gains. This result is in line with the European Commission view (Roeger et al., 2008) that margins need to reach a certain level in order to stimulate innovation in these sectors. At the opposite, greater competition in services would consistently promote productivity gains.Labour productivity, Competition, Cross-country and Sectoral Study

How quickly does structural reform pay off? An empirical analysis of the short-term effects of unemployment benefit reform

While there is a fairly broad consensus regarding the potential adverse effects of generous unemployment benefit insurance on steady-state employment, the short-term effects of benefit reforms are not well-established. This paper contributes to fill this gap by estimating impulse responses to benefit reform shocks identified for a panel of OECD countries. Findings indicate that although it takes time for unemployment benefit reforms to pay off, such reforms do not appear to entail any negative short-run effects. There is however some suggestive evidence that reducing unemployment benefits could have negative short-run effects in bad times

The Kondo-Hubbard model at half-filling

We have analyzed the antiferromagnetic (J>0) Kondo-Hubbard lattice with the band at half-filling by means of a perturbative approach in the strong coupling limit, the small parameter is an arbitrary tight-binding band. The results are valid for any band shape and any dimension. We have obtained the energies of elementary charge and spin excitations as well as the magnetic correlations in order to elucidate the magnetic and charge behavior of the Kondo lattice at half-filling. Finally, we have briefly analyzed the ferromagnetic case (J<0), which is shown to be equivalent to an effective antiferromagnetic Heisenberg model.Comment: 4 pages, Proceedings of SCES98/Pari