Application of the fair value from decisions

Este texto revisa el impacto en la toma decisiones que tendrán que afrontar los administradores y usuarios de la información financiera con la entrada de las Normas Internacionales de Información Financiera NIIF para la preparación y presentación de los Estados financieros en Colombia, y en especial con la incorporación del concepto de valor razonable para la medición de activos y pasivos, lo cual en teoría hará que estos usuarios tengan una mejor percepción de la realidad de la Compañía para la toma de decisiones, sin embargo, también existen desventajas las cuales describiremos a lo largo del ensayo. Teniendo en cuenta lo anterior, el propósito de este ensayo es el de responder la pregunta ¿Cuál es el impacto del concepto de valor razonable en la generación de información útil para la toma de decisiones? El ensayo se ha estructurado de la siguiente manera: en primer lugar se presentan los conceptos básicos y el sistema actual de medición en Colombia, continuamos con el concepto de valor razonable desde el punto de vista filosófico utilizando miradas subjetivas y objetivas, posteriormente se muestran diferentes opiniones de autores acerca de los beneficios y desventajas a la hora de adoptar el método de Valor razonable para la medición y finalmente presentamos unas conclusiones a modo de resumen.This paper reviews the impact on decision making that will be faced by administrators and users of financial information with the entry of International Financial Reporting Standards IFRS for the preparation and presentation of financial statements in Colombia, especially with the addition the concept of fair value to measure assets and liabilities, which in theory will make these users have a better perception of the reality of the Society for decision making, however, there are also disadvantages which describe over assay. Given the above, the purpose of this essay is to answer the question: What is the impact of fair value concept in generating information useful for decision making? The essay is structured as follows: first the basic concepts and the current measurement system are presented in Colombia, we continue with the concept of fair value from a philosophical point of view using subjective and objective looks, then is different opinions of authors about the benefits and disadvantages in adopting the fair value method for measuring and finally present some conclusions in summary

Phosphorous cycling in the Gulf of Maine : a multi-tracer approach

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1998Knowledge of temporal and spatial nutrient turnover and export rates is of great importance for a variety of investigations, ranging from nutrient limitation to contamination uptake and removal. However, there are few methods that allow for the in situ elucidation of these processes. In this thesis research, in situ phosphorus turnover rates and upper ocean export were determined within the southwestern Gulf of Maine using the naturally occurring radionuclides phosphorus-32 (t_= 14.3 d), phosphorus-33 (t_ = 25.3 d), thorium-234 (t_ = 24.1) and beryllium-7 (t_ = 53.3 d). New techniques were developed for the extraction, purification and measurement of 32p and 33p in rainwater and in inorganic, organic and particulate pools in seawater. In order to constrain the input ratio of 33p/32p, rain samples were collected and measured continuously for 32p and 33p, as well as 7Be and 21OPb, from March 1996 to March 1998 at Woods Hole, MA, and from March 1997 to October 1997 at Portsmouth, NH. The average 33p;32p ratio was 0.88 ± 0.14. 32p, 33p, 7Be and 210Pb were further used to determine aerosol residence times and as possible tracers of stratospheric/tropospheric exchange during severe storm events. F our cruises were conducted in Wilkinson Basin, in the Gulf of Maine, during the spring and summer of 1997. 234Th was used to estimate advection and diffusion using 1D steady state and multi-dimensional non-steady state models. Export ratios (export/primary production) were found to range between 0.11 and 0.37. Vertical eddy diffusivity found using 7Be varied from 0.5 to 1.5 cm2 sec-I. Significant changes in phosphorus turnover rates within the reservoirs which contained 32p and 33p activity were found between the spring and summer months. In late summer, bacterial activity was substantial, significantly affecting the residence times of dissolved inorganic and organic phosphorus pools. Our results clearly show that 32p and 33p can provide much needed information regarding the biogeochemical cycling of P in marine systems and can be of use in the development of ecosystem models which seek to address mechanisms which affect primary production in the ocean.Funding for this work was provided by the Office of Naval Research Fellowship Program, The Environmental Protection Agency Science to Achieve Results (STAR) Fellowship Program, the National Science Foundation (Grant no. OCE-9633240) and the Woods Hole Oceanographic Institution (unrestricted funds)

South Carolina Stormwater Detention Ponds: Sediment Accumulation and Nutrient Sequestration

Stormwater detention ponds are prevalent across South Carolina and receive runoff waters carrying both nutrients and sediments. As sediments accumulate in these ponds, water volume is reduced leading to a decrease in runoff retention. Periodic dredging is required to maintain pond function, but dredging is costly and there is little data available to support how often pond dredging is required. It is further unknown how high nutrient loading effects sediment nutrient sequestration and autochthonous production of organic sediment components

Marine sedimentary organic matter: delineation of marine and terrestrial sources through radiocarbon dating; and the role of organic sulfur in early petroleum generation

Thesis (M.S.)--Joint Program in Oceanography and Oceanographic Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), June 1996."May 1996."Includes bibliographical references (leaves 66-68).This thesis details two years of research conducted with the guidance and support of three advisors: Dr. J. K. Whelan, Dr. J. S. Seewald and Dr. T. I. Eglinton. Each of the three chapters represents a different, self-contained research project. All of the projects are related to the organic geochemistry of marine sediments, however, this is a fairly encompassing area of study. Chapters 1 and 2 stem from the same experimental study -- the use of hydrous-pyrolysis to investigate mechanisms leading to the production of petroleum-related products during kerogen maturation. Chapter 3, on the other hand, utilizes a recently developed technique of isolating and AMS-14C dating individual compounds from complex sedimentary organic mixtures. The samples used in each investigation came from all over the world. The first two chapters utilize ancient marine sediment samples obtained from an outcrop in California (Chpts. 1 and 2) and from a well in Alabama (Chpt. 2). In contrast, recent marine sediment samples were obtained from the Arabian and Black Seas for the third chapter. Several preparative and analytical methods are common to all three studies. Nevertheless, each employ techniques totally unique from one another and from previous investigations. In Chapter 1, for example, X-ray absorption spectroscopy (XANES) is used to determine the speciation of organic sulfur present in kerogen, bitumen, and bulk sediment samples. While Chapter 3 represents the first study in which the "4C ages of individual, known hydrocarbon biomarkers are determined after isolation by Preparative Capillary Gas Chromatography (PCGC). The insights gained by these investigations are discussed in detail in the following chapters. The common thread between the three chapters is that the source of organic matter, the rate at which it is delivered to marine sediments and the depositional environment, all set the stage for kerogen formation and eventual petroleum generation.by Bryan C. Benitez-Nelson.M.S

Phosphorus cycling in the Gulf of Maine : a multi-tracer approach

Thesis (Ph.D.)--Joint Program in Oceanography, Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, 1999 [February 1999]Vita.Includes bibliographical references.by Claudia R. Benitez-Nelson.Ph.D

Biogeochemical responses to late-winter storms in the Sargasso Sea, III—Estimates of export production using 234Th:238U disequilibria and sediment traps

Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 56 (2009): 875-891, doi:10.1016/j.dsr.2009.01.008.Direct measurements of new production and carbon export in the subtropical North Atlantic Ocean appear to be too low when compared to geochemical based estimates. It has been hypothesized that episodic inputs of new nutrients into surface water via the passage of mesoscale eddies or winter storms may resolve at least some of this discrepancy. Here, we investigated particulate organic carbon (POC), particulate organic nitrogen (PON), and biogenic silica (BSiO2) export using a combination of water column 234Th:238U disequilibria and free-floating sediment traps during and immediately following two weather systems encountered in February and March 2004. While these storms resulted in a 2-4 fold increase in mixed layer NO3 inventories, total chlorophyll a and an increase in diatom biomass, the systems was dominated by generally low 234Th:238U disequilibria, suggesting limited particle export. Several 234Th models were tested, with only those including non-steady state and vertical upwelling processes able to describe the observed 234Th activities. Although upwelling velocities were not measured directly in this study, the 234Th model suggests reasonable rates of 2.2 to 3.7 m d-1. Given the uncertainties associated with 234Th derived particle export rates and sediment traps, both were used to provide a range in sinking particle fluxes from the upper ocean during the study. 234Th particle fluxes were determined applying the more commonly used steady state, 1-dimensional model with element/234Th ratios measured in sediment traps. Export fluxes at 200 m ranged from 1.91 ± 0.20 to 4.92 ± 1.22 mmol C m-2 d-1, 0.25 ± 0.08 to 0.54 ± 0.09 mmol N m-2 d-1, and 0.22 ± 0.04 to 0.50 ± 0.06 mmol Si m-2 d-1. POC export efficiencies (Primary Production/Export) were not significantly different from the annual average or from time periods without storms, although absolute POC fluxes were elevated by 1-11%. This increase was not sufficient, however, to resolve the discrepancy between our observations and geochemical based estimates of particle export. Comparison of PON export rates with simultaneous measurements of NO3 - uptake derived new production rates, suggested that only a fraction, < 35%, of new production was exported as particles to deep waters during these events. Measured bSiO2 export rates were more than a factor of two higher (p < 0.01) than the annual average, with storm events contributing as much as 50% of annual bSiO2 export in the Sargasso Sea. Furthermore it appears that 65 - 95% (average 86 ± 14%) of the total POC export measured in this study was due to diatoms. Combined these results suggest that winter storms do not significantly increase POC and PON export to depth. Rather, these storms may play a role in the export of bSiO2 to deep waters. Given the slower remineralization rates of bSiO2 relative to POC and PON, this transport may, over time, slowly decrease water column silicate inventories, and further drive the Sargasso Sea towards increasing silica limitation. These storm events may further affect the quality of the POC and PON exported given the large association of this material with diatoms during these periods.This study was funded by the National Science Foundation (Chemical Oceanography Grants OCE-0244612 and OCE-0241645)

An Artificial Habitat Increases the Reproductive Fitness of a Range-shifting Species within a Newly Colonized Ecosystem

When a range-shifting species colonizes an ecosystem it has not previously inhabited, it may experience suboptimal conditions that challenge its continued persistence and expansion. Some impacts may be partially mitigated by artificial habitat analogues: artificial habitats that more closely resemble a species\u27 historic ecosystem than the surrounding habitat. If conditions provided by such habitats increase reproductive success, they could be vital to the expansion and persistence of range-shifting species. We investigated the reproduction of the mangrove tree crab Aratus pisonii in its historic mangrove habitat, the suboptimal colonized salt marsh ecosystem, and on docks within the marsh, an artificial mangrove analogue. Crabs were assessed for offspring production and quality, as well as measures of maternal investment and egg quality. Aratus pisonii found on docks produced more eggs, more eggs per unit energy investment, and higher quality larvae than conspecifics in the surrounding salt marsh. Yet, crabs in the mangrove produced the highest quality larvae. Egg lipids suggest these different reproductive outcomes result from disparities in the quality of diet-driven maternal investments, particularly key fatty acids. This study suggests habitat analogues may increase the reproductive fitness of range-shifting species allowing more rapid expansion into, and better persistence in, colonized ecosystems

What is the initiation step of the Grubbs-Hoveyda olefin metathesis catalyst?

Density function theory calculations reveal that the Grubbs-Hoveyda olefin metathesis pre-catalyst is activated by the formation of a complex in which the incoming alkene substrate and outgoing alkoxy ligand are both clearly associated with the ruthenium centre. The computed energies for reaction are in good agreement with the experimental values, reported here

An improvement in the small-volume technique for determining thorium-234 in seawater

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Marine Chemistry 100 (2006): 282-288, doi:10.1016/j.marchem.2005.10.016.The recently developed 2‐5 L small‐volume MnO2 coprecipitation method for determining 234Th in seawater has provided a new way to substantially increase, both temporally and spatially, the sampling resolution of 234Th and 234Th‐based particulate organic carbon export estimates in the upper ocean. In this study, we further optimize the technique by reducing reagent quantities and the use of an additional water bath heating step. This optimization allows the filtration of the MnO2 precipitate onto a 25‐mm diameter, 1.0 μm pore size QMA filter to be completed within < 30 minutes for unfiltered waters from the South China Sea. In addition, we have modified the MnO2 purification procedure to allow for alpha spetrometric measurements of 234Th recoveries. Results from recovery experiments suggest that reagent amounts can be reduced to 0.0375 mg KMnO4 and 0.1 mg MnCl2∙4H2O per liter of sample, while still maintaining high 234Th recovery. This study further confirms that the addition of a yield monitor is necessary for the application of this small‐volume method.Support for this work came from the Natural Science Foundation of China through grants #40206011, #49825162, and #90211020. This study was also supported by the China Ministry of Education through a program for Changjiang Scholars and Innovative Research Teams in Universities (PRSIRT)

A Time Series of Water Column Distributions and Sinking Particle Flux of Pseudo-Nitzschia and Domoic Acid in the Santa Barbara Basin, California

Water column bulk Pseudo-nitzschia abundance and the dissolved and particulate domoic acid (DA) concentrations were measured in the Santa Barbara Basin (SBB), California from 2009–2013 and compared to bulk Pseudo-nitzschia cell abundance and DA concentrations and fluxes in sediment traps moored at 147 m and 509 m. Pseudo-nitzschia abundance throughout the study period was spatially and temporally heterogeneous (L−1 to 3.8 × 106 cells L−1 , avg. 2 × 105 ± 5 × 105 cells L−1 ) and did not correspond with upwelling conditions or the total DA (tDA) concentration, which was also spatially and temporally diverse (1000 cells L−1 and tDA = 200 ng L−1 ) measured as deep as 150 m. Our results highlight that dDA should not be ignored when examining bloom toxicity. Although water column abundance and pDA concentrations were poorly correlated with sediment trap Pseudo-nitzschia abundance and fluxes, DA toxicity is likely associated with senescent blooms that rapidly sink to the seafloor, adding another potential source of DA to benthic organisms