On the Valuation of Companies with Growth Opportunities

Each company faces day to day investment opportunities. Just by staying in business the company is taking a decision of reinvesting capital. These opportunities have to be fairly valued to overcome misallocation of resources. A project with high growth opportunities requires high reinvestments to take full advantage of them until it reaches its mature stage. These investments can be seen as a succession of call options on future growth. When a company with such prospects is valued using the discounted cash flow technique and growth is taken implicitly in the growing cash flows and the residual value, the value thus obtained will be higher than the true one (under certain circumstances). Technology advances and the effects of globalization create enormous growth opportunities, and so misvaluation risks are higher.real options; valuation; contingent claims valuation

Effect of elevated inorganic carbon on the cytosolic homeostasis of NO3- in the marine angiosperm Posidonia oceanica (L.) Delile

The marine angiosperm Posidonia oceanica is a mediterranean endemism of great ecological significance. As other marine plants, P. oceanica has adapted secondarily to the marine environment and develop anew different mechanisms to colonize it. Among others, this plant has developed a plasma membrane system for the direct uptake of bicarbonate. In this work we have developed both NO3- and Cl- selective microelectrodes for the continuous monitoring of the intracellular (cytosolic) NO3- and Cl-. In the light, leaf mesophyll cells show a cytosolic NO3- concentration of 5.7±0.2 mM (n=10), while in the dark cytosolic NO3- raises up to 8.7±1.1 mM; these values are in the range of concentrations quoted for Arabidopsis thaliana (Cookson et al., 2005). The enrichment of natural seawater (NSW) with 3 mM NaHCO3 caused a decrease of the cytosolic NO3- concentration of 1 mM and a decrease of the cytosolic concentration of Cl- of 3.5 mM. The saturation of NSW with 1000 µL CO2 L-1 produced a lower diminution of the cytosolic NO3- (0.3 mM). In the presence of 0.1 mM of the plasma membrane permeable inhibitor of the carbonic anhydrase (EZ) the diminution of cytosolic NO3- caused by the same concentration of CO2 was much lower, 0.1 mM. The addition of inorganic carbon, either HCO3- or CO2, has an effect on the cytosolic mechanisms for anionic homeostasis, one of which is the opening of the slow anion channels. These channels are permeable to NO3- and Cl- and could elicit the efflux of these ions. In P. oceanica, the response in the presence of EZ points out that the inorganic carbon species that cause the NO3-/Cl- efflux is HCO3-. This effect could contribute to plant biomass N dilution observed in elevated CO2. References: Cookson et al. 2005. Plant Physiology 138, 1097–1105.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Manejo de la producción equina e impacto ambiental: el caso de establecimientos en Buenos Aires (Argentina)

La producción equina en Buenos Aires (Argentina) es de 512847 cabezas. El manejo de la producción equina es un factor importante para la minimización de los efectos ambientales. Este manejo incluye la implementación de buenas prácticas. El objetivo de este trabajo es caracterizar los establecimientos de producción equina en Buenos Aires en cuanto a su manejo y evaluar el posible impacto ambiental que pueden generar. Se han caracterizado 16 establecimientos según las fuentes de abastecimiento de agua, cantidad y profundidad de los pozos, raza, sistema productivo, tipo y gestión de camas, tipo de alimentación, prácticas veterinarias, suplementos dietarios utilizados, y manejo de la alimentación. Este trabajo es el primer estudio sobre los efectos ambientales de la producción equina en Argentina.Equine production in Buenos Aires (Argentina) is 512847 heads. The equine production management is an important factor for the minimization of environmental effects. This management includes the implementation of good practices. The aim of this paper is to characterize the equine production paddocks in Buenos Aires in terms of their management, and to evaluate the possible environmental impact they may generate. Sixteen paddocks have been characterized according to the sources of water supply, quantity and depth of the wells, breed, productive system, type and management of beds, type of feed, feeding practices, supplementation, other ration components and management. These are the first studies on environmental effects of equine production in Argentine.Fil: Vaccaro, Mariana Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; ArgentinaFil: García Liñeiro, José Alberto. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Fernandez Cirelli, Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Unidad Ejecutora de Investigaciones en Producción Animal. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Unidad Ejecutora de Investigaciones en Producción Animal; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Centro de Estudios Transdisciplinarios del Agua; Argentin

NO3- selective mini-electrodes as a tool to investigate the NO3- traffic in Chlamydomonas reinhardtii D.

Ion selective NO3- mini-electrodes were used to measure the external NO3- concentration in C. reinhardtii liquid cultures. Electrodes were prepared using glass capillaries (1.5 mm external diameter). Capillaries were cut in 10 cm long pieces, dehydrated for 45 minutes in an oven and silanized by addition of dimethyldichlorosilane in bencene 0.1% (V/V). Once silanized, the capillaries were baked again for 30 minutes. Once cold the capillaries were backfilled with the NO3- ionophore (Fluka: 72549), which contains PVC (5.75% w/w) dissolved in tetrahydrofurane. Then, the NO3- mini-electrodes were stored in dark in a desiccator until tetrahydrofurane gets evaporated. Before use, NO3- selective mini-electrodes were backfilled with 0.1 M NaNO3 and 0.1 M KCl and connected to a high-impedance differential amplifier (WPI FD223). Mini-electrodes were calibrated in N-free Beijerinck medium, which contains 0.1 mM Cl-. In those conditions, electrodes calibration slope was 54 mV/p NO3- in the range 1 - 1000 µM NO3-. The mini-electrodes were used to continuous monitoring of the external NO3- concentration in liquid culture of different C. reinhardtii strains, incubated in N-free Beijerinck medium supplemented with 100 µM NO3Na. Previous to the assays, strains were N starved for 6 days. In the light, wild type strain uptakes NO3- at a rate of 15 nmol NO3-·106 cells-1·h-1, in the dark this rate was one third of this figure. After 5 h, the external NO3- levelled off at 10 µM in the light and around 30 µM in the dark. C. reinhardtii cells cultured in the presence of 2 mM NO3NH4 do not show significant NO3- uptake nor a mutant strain, defective in nitrate transport and having an active nitrate reductase. However, a mutant strain lacking the nitrate reductase shows an enhanced NO3- uptake rate, compared with the value obtained for the wild type in the light.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

HCO3- enrichment causes cytosolic NO3- efflux in Posidonia oceanica leaf cells

Posidonia oceanica is a seagrass, the only group of vascular plants to colonize the marine environment. Seawater is an extreme yet stable environment, characterized by high salinity, alkaline pH and low availability of essential nutrients, such as nitrate or phosphate. In addition, in aquatic environments the supply of CO2 for the photosynthesis is limited by diffusion and therefore many aquatic plants use HCO3- as the inorganic carbon source for photosynthesis. Previous results have shown that Na+ -dependent transport systems operate on the plasma membrane of P. oceanica mesophyll leaf cells for the high-affinity NO3-, Pi or amino acids uptake. Also, a direct transport of HCO3- driven by H+ has been found in this species that provides inorganic carbon for photosynthesis and could be a significant component of a carbon concentrating mechanism in this species. Interestingly, this HCO3- direct uptake caused the efflux of chloride from the cytosol, probably through S-type anion channels, pointing that other anions could also be removed from the cytosol. This hypothesis could be relevant in the case of NO3-, since the decrease of cytosolic NO3- in response to HCO3- enrichment could limit N-assimilation. Here we analyse the effect of HCO3- increase on NO3- uptake and cytosolic homeostasis in P. oceanica. Enrichment of natural seawater with 3 mM HCO3- evokes the on-going decrease of cytosolic NO3-, from 5.7 ± 0.2 to 4.8 ± 0.7 mM after 40 min of treatment. The incubation of P. oceanica leaf pieces in 3 mM HCO3- NSW causes an initial increase of NO3- concentration in the medium. Maximum efflux (21 nmol NO3- gFM-1 min-1) occurs within the first minute of incubation. Then, external NO3- is depleted from the medium at lower net uptake rate than the value observed in non HCO3- -enriched natural seawater. These results fit the hypothesis that HCO3- enrichment causes the nitrogen loose and could impair nitrogen assimilation promoting N biomass impoverishment.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Spanish MINECO, projects BFU2017-85117-R and BIO2016-81957-RED

The Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like Episode Syndrome-associated Human Mitochondrial tRNALeu(UUR) Mutation Causes Aminoacylation Deficiency and Concomitant Reduced Association of mRNA with Ribosomes

The pathogenetic mechanism of the mitochondrial tRNALeu(UUR) A3243G transition associated with the mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome has been investigated in transmitochondrial cell lines constructed by transfer of mutant mitochondrial DNA (mtDNA)-carrying mitochondria from three genetically unrelated MELAS patients or of isogenic wild-type mtDNA-carrying organelles into human mtDNA-less cells. An in vivo footprinting analysis of the mtDNA segment within the tRNALeu(UUR) gene that binds the transcription termination factor failed to reveal any difference in occupancy of sites or qualitative interaction with the protein between mutant and wild-type mtDNAs. Cell lines nearly homoplasmic for the mutation exhibited a strong (70-75%) reduction in the level of aminoacylated tRNALeu(UUR) and a decrease in mitochondrial protein synthesis rate. The latter, however, did not show any significant correlation between synthesis defect of the individual polypeptides and number or proportion of UUR codons in their mRNAs, suggesting that another step, other than elongation, may be affected. Sedimentation analysis in sucrose gradient showed a reduction in size of the mitochondrial polysomes, while the distribution of the two rRNA components and of the mRNAs revealed decreased association of mRNA with ribosomes and, in the most affected cell line, pronounced degradation of the mRNA associated with slowly sedimenting structures. Therefore, several lines of evidence indicate that the protein synthesis defect in A3243G MELAS mutation-carrying cells is mainly due to a reduced association of mRNA with ribosomes, possibly as a consequence of the tRNALeu(UUR) aminoacylation defect