The quest for corporate growth

Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1996.Includes bibliographical references (leaves 116-122).by Gabriel D. Obrador Ramos and Edmundo E. Ruiz Rodriguez.M.S

Characterization And Modeling Of Antireflective Coatings Of Si O 2, Si3 N4, And Si Ox Ny Deposited By Electron Cyclotron Resonance Enhanced Plasma Chemical Vapor Deposition

In this work the optical transmission spectra of silicon oxide (Si O2), silicon nitrides (Si3 N4), silicon-rich oxynitrides (Si Ox Ny), and antireflective coatings (ARCs), deposited by the electron cyclotron resonance enhanced plasma chemical vapor deposition onto a silicon substrate at room temperature, are studied. Simulations carried out with the MATHEMATICA program, from 0 to 1000 nm thick coatings, showed maximum transmittance in the three basic colors at 620, 480, and 560 nm for the Si O2, Si3 N4, and Si Ox Ny ARCs, respectively. However, a highly significant transmittance over a broad spectral range from visible (VIS) to near the infrared region, with optical gain in the three basic colors above 20%, is observed only at thicknesses of 80, 70, and 60 nm, respectively, for Si O2, Si3 N4, and Si Ox Ny ARCs. Among the three evaluated films, the highest transmittance in the broad spectral band in the VIS range was observed for 60 nm thick Si3 N4 films. The Fourier transform infrared spectroscopy of these films reveal high structural quality and the presence of Si-O, Si-H, N-H, and Si-N bonds, independent of thickness and deposition parameters. © 2006 American Vacuum Society.242823827White, M., Lampe, D., Blaha, F., Mack, I., (1974) IEEE J. Solid-State Circuits, SC-9, p. 1Furumiya, M., Ohkubo, H., Muramatsu, Y., Kurosawa, S., Okamoto, F., Fujimoto, Y., Nakashiba, Y., (2001) IEEE Trans. Electron Devices, 48, p. 2221Popov, O.A., Waldron, H., (1989) J. Vac. Sci. Technol. A, 7, p. 914Heavens, O.S., (1991) Optical Properties of Thin Solid Films, , Dover, New YorkAroutiounian, V.M., Maroutyan, K.R., Zatikyan, A.L., Touryan, K.J., (2002) Thin Solid Films, 403, p. 517Edwards, D.F., (1985) Handbook of Optical Constants of Solids, , edited by E. D.Palik (Academic, Washington, D.CGreen, M.L., Gusev, E.P., Degraeve, R., Garfunkel, E.L., (2001) J. Appl. Phys., 90, p. 2057Alayo, M.I., Pereyra, I., Scopel, W.L., Fantini, M.C.A., (2002) Thin Solid Films, 402, p. 154Tsu, D.V., Lucovsky, G., Mantini, M.J., Chao, S.S., (1987) J. Vac. Sci. Technol. A, 5, p. 1998Lucovsky, G., Richard, P.D., Tsu, D.V., Lin, S.Y., Markunas, J., (1986) J. Vac. Sci. Technol. A, 4, p. 681Joseph, E.A., Gross, C., Liu, H.Y., Laaksonen, R.T., Celii, F.G., (2001) J. Vac. Sci. Technol. A, 19, p. 2483Wu, X., Ossadnik, Ch., Eggs, Ch., Veprek, S., Phillipp, F., (2002) J. Vac. Sci. Technol. B, 20, p. 1368Diniz, J.A., Do Couto, A.L., Danilov, I., Tatsch, P.J., Swart, J.W., (1999) Proceedings of the XIV International Conference of Microelectronics and Packaging, p. 164Tsu, D.V., Lucovsky, G., Mantini, M.J., (1986) Phys. Rev. B, 33, p. 7069Denisse, C.M.M., Troost, K.Z., Oude Elferink, J.B., Habraken, F.H.P.M., Van Der Weg, W.F., (1986) J. Appl. Phys., 60, p. 253

Late Pleistocene palaeoproductivity patterns during the last climatic cycle in the Guyana Basin as revealed by calcareous nannoplankton

Variations in the assemblage and abundance of coccoliths reveal changes in oceanic and atmospheric dynamics in the Guyana Basin over the last climatic cycle, mainly linked to latitudinal variations in the ITCZ (Intertropical Convergence Zone). Records of the N ratio (a palaeoproductivity index of coccolithophores) allowed us to monitor nutri-thermocline fluctuations. Nannofossil accumulation rates (NAR) vary closely with the N ratio, indicating a strong correlation between these two palaeoproductivity proxies. Decreases in the N ratio and NAR values suggest lower palaeoproductivity during glacial substages, indicating a deep nutri-thermocline (deep stratification of the mixed layer) as a consequence of the piling up of warm water dragged by the NEC. This setting was favoured by the southern shift of the ITCZ and Trade winds which blew perpendicular to the Guyana coast. By contrast, increases in the N ratio and NAR values revealed higher palaeoproductivity during interglacial substages, suggesting a shoaling of the nutri-thermocline. This scenario is favoured by a northward displacement of the ITCZ with the southeast Trade winds blowing alongshore. Additionally, palaeoproductivity changes during substages of Marine Isotope Stage (MIS) 6-5 are of much higher amplitude than those recorded in substages of MIS 4-2 and the early Holocene. Similarities between the palaeoproductivity and the 65° N summer insolation records, suggest a link between the depth of nutri-thermocline, the latitudinal migration of the ITCZ and ice-sheet changes in the Northern Hemisphere

Occupational and Environmental Risks from Mancozeb in Aviation Facilities in the Banana Producing Area of Teapa, Tabasco, Mexico

Purpose: To identify occupational risks and practices in the four aerial fumigation facilities in the Sierra banana growing region and to evaluate environmental impacts from Mancozeb use.Methods: Occupational health risks were identified and practices in the four aerial fumigation facilities in the Sierra banana growing region were documented. Semi-structured interviews were conducted with installation managers. To evaluate environmental impact, samples of water and soil were collected and analysed in an acute toxicity bioassay with Vibrio fischeri, using uncontaminated soil and water to establish background levels.Results: Even in the largest and best-equipped facility, serious risks to workers’ health were encountered from inadequate use of protective equipment by workers. Furthermore, excessive use of pesticide, lack of re-use of unused product, poor facility design and poor use of wash-water were observed, resulting in  maximum toxicity of > 5 times background in discharged water. Parallel soil samples were > 20 times  more toxic than background, being most toxic at > 0.5 km from the discharge point.Conclusion: Areas of opportunity to improve worker health and the environment include proper and  consistent use of protective equipment, re-use of unused product, wastewater reduction and appropriate wastewater treatment.Keywords: Black Sigatoka, Ethylene thiourea, Fumigation, Pesticide, Mancozeb, Airports, Microtox, Vibrio fischeri, Occupational health risks, Toxicit

Motivar el aprendizaje utilizando nuevas tecnologías: Monitorización continua de glucosa

La innovación pretende: motivar, cambiar “el saber por saber hacer”, “fomentar el uso de nuevas tecnologías”, etc. Creemos que este proyecto abarca todo lo expuesto. La diabetes es la enfermedad endocrina más prevalente y la 7ª causa de muerte en el mundo. Los monitores continuos de glucosa son de gran ayuda para controlar la glucemia y reducir el riesgo de patología diabética. Hemos aprovechado esta idea para motivar a los estudiantes, e involucrarlos en esta propuesta de Flipped learning que nos ha llevado a elaborar un vídeo titulado “Monitorización continua de la glucemia”, en el que ellos mismos explican el funcionamiento y utilidad de este avance tecnológico. Con este proyecto hemos logrado: a) que constataran la importancia del páncreas en el control de la glucemia (al comparar los resultados obtenidos en estudiantes sanos con los de pacientes diabéticos); b) fomentar el uso de nuevas tecnologías; c) motivar y favorecer el aprendizaje autónomo y colaborativo; d) hacerlos protagonistas del vídeo y responsables de trasladar lo aprendido a sus compañeros; e) crear un material docente de calidad, útil para estudiantes, profesionales de Ciencias de la Salud y pacientes diabéticos (usuarios potenciales de estos dispositivos), disponible a través de las redes sociales

Recurs multimedia del treball de camp en geologia

El portal Geocamp s'ha creat per aplicar-lo al procés d'aprenentatge de la Geologia al camp, enllaçant conceptes teòrics amb metodologia de treball fora de l'aula o el laboratori. S'adreça a docents i estudiants d'universitat, secundària, batxillerat, formació de professorat o públic en general. Aquest portal conté materials didàctics propis i enllaços amb tot tipus d'informacions relatives al treball de camp en Ciències de la Terra. L'element més innovador rau en la seva utilitat a l'hora de plantejar les activitats de preparació de les excursions. També hi trobem pautes metodològiques per a treballar en els afloraments, idees sobre les activitats de síntesi etc. Geocamp consta de 4 blocs: "Preparem la sortida" (elecció del lloc, transport, predicció meteorològica, material necessari, materials didàctics, enllaços d'interès etc.), "El treball de camp" (pautes d'observació, descripció i interpretació de les roques, recomanacions de seguretat etc.), "Itineraris" (exemples regionals propis o disponibles a la xarxa) i "Després de la sortida" (propostes de realització d'un informe final etc.)

Adaptability of sugarcane (Saccharum spp.) clones, introduced by exchange to southeastern Mexico.

ABSTRAC Objetive: To evaluate sugarcane clones in the adaptability phase, and select those with higher yield in field and factory than commercial control clones. Design/methodology/approach: 14 clones of sugarcane in the first cycle were evaluated. The experimental design consisted of randomized complete blocks with four replications. The following agricultural characteristics were evaluated: stem weight, population and yield; as well as the industrial characteristics: sucrose content, juice purity and theoretical sugar production. They were compared with the values ​​of local clones MEX 69-290 and CP 72-2086 that served as controls. Results: There were found statistical differences in agricultural and industrial characteristics between clones. In stem weight, clone LTMEX 94-02 was the heaviest. In population, clone Mex 95-35 was the one that presented the highest number of stems per ha. Regarding yield in the field, clone COLPOSCTMEX 09-1433 was the one that obtained significantly higher tonnage per hectare compared to the two control clones. Among the factory characteristics, the clone MEX 96-10 had a significantly higher concentration of sucrose and with the highest value in juice purity, and in theoretical sugar production. Clone COLPOSCTMEX 09-1433 presented the highest value of theorical sugar yield in comparison to the two control clones. Limitation on study/implications: Although data from the new clones are relevant, they belong to an only one cycle. Findings/conclusions: At least four clones evaluated showed high field and factory yields: COLPOSCTMEX 09-1433, LTMEX 94-02, MEX 95-59, and MOTZMEX 00-1192. In all four, field yield was statistically superior to that of the control MEX 69-290; thus, it is pertinent to continue with its evaluation and multiplication in the semi-commercial test phase. However, since they are introduced from other geographical regions, it is recommended to continue their evaluation under the environmental conditions of the region.Objective: To evaluate sugarcane (Saccharum spp.) clones in the adaptability phase and select those with high field and factory yields that significantly exceed the commercial control clones.Design/Methodology/Approach: Fourteen sugarcane clones were evaluated in a crop established for the first time and to which no cut has been made. The experimental design consisted of randomized complete blocks with four repetitions. The following agricultural characteristics were evaluated: stalk weight, population, and yield. The following industrial characteristics were likewise assessed: sucrose content, juice purity, and theoretical sugar production. Both values were compared with the values of the local clones MEX 69-290 and CP 72-2086 that were used as control.Results: Statistical differences were found in agricultural and industrial characteristics between clones. In terms of stalk weight, the LTMEX 94-02 clone stood out, while, in population terms, the Mex 95-35 clone recorded the highestnumber of stalks per ha. Regarding field yield, the COLPOSCTMEX 09-1433 clone obtained significantly higher tonnage per hectare than the two control clones. Among the factory characteristics, the MEX 96-10 clone stood out with a significantly higher concentration of sucrose and with the highest juice purity. Finally, the COLPOSCTMEX 09-1433 clone had the highest theoretical sugar production value, which was statistically superior to the two control clones.Study Limitations/Implications: The data were obtained from a crop establishedfor the first time.Findings/Conclusions: At least four clones showed high field and factory yields: COLPOSCTMEX 09-1433, LTMEX 94-02, MEX 95-59, and MOTZMEX 00-1192. All four showed a field performance that had better statistics than the control MEX 69-290; therefore, it would be appropriate to pursue its evaluation and multiplication during the semi-commercial test phase. However, since they were introduced, their evaluation should continue under the environmental conditions of the region

Impact of iceberg melting on Mediterranean thermohaline circulation during Heinrich events

Down-core samples of planktonic and benthic foraminifera were analyzed for oxygen and carbon isotopes in International Marine Past Global Changes Study (IMAGES) core MD99-2343 in order to study the interactions between climate change in the Northern Hemisphere and the western Mediterranean thermohaline circulation at times of Heinrich events (HE). Our results confirm the antiphase correlation between enhanced North Atlantic Deep Water formation and low ventilation in the Mediterranean. However, this study reveals that this antiphase relationship in deepwater formation between the North Atlantic and Mediterranean was interrupted during times of HE when the injection of large volumes of water from melting icebergs reached the entrance to the Mediterranean. These events, which lasted less than 1000 years, are represented by pronounced decreases in both planktonic d18O and benthic d13C signals. Lower salinities of Mediterranean surface water resulted in a slowdown of western Mediterranean deepwater overturn even though cold sea surface temperatures and drier climate should have resulted in enhanced deepwater formation

Cultivo e incorporación de Crotalaria juncea L. en un suelo cañero de la Chontalpa, Tabasco, México

Objetive: to analyze in a sugarcane soil, the yield in aerial biomass of sunn hemp (Crotalaria juncea L.) (Fabaceae) with and without nitrogen fertilization in two periods of cut (40 and 60 d), and to evaluate the changes in its fertility in two dates subsequent to its incorporation Design/methodology/approach: two fertilization treatments NPK 00-60-60 and 120-60-60 and a control were tested. At the beginning of the experiment, 15 and 30 days after the harvest and incorporation of the sunn hemp, compound samples of soil were taken (0-30 cm) to analyze them chemically. Results: in total dry weight (PS) and the aerial components (stem and leaves) of the legume there were no significant differences between treatments, their average yield was 7.08 and 7.16 t ha-1 for the 40 and 60 day cuts, respectively. The N did not show significant differences between doses or cutting season; their average accumulation was 151.61 and 176.37 kg ha-1 for the respective cuts. The P showed higher values and significant differences in the fertilized treatments. Soil analysis before planting showed optimal properties, except for the low OM content. Study limitations/implications: the sensitivity of some of its components may make it difficult to detect changes in OM; the OSC is an alternative and easily measurable parameter, although it is also advisable to follow up in the long term. Findings/Conclusions: the incorporation of sunn hemp to the soil is a viable and promising alternative to restore the N used and incorporate the environment, in addition, OM improves its physical, chemical and biological fertility.Objetivo: analizar en un suelo cañero, el rendimiento en biomasa aérea de crotalaria (Crotalaria juncea L.) (Fabaceae) con y sin fertilización nitrogenada en dos épocas de corte (40 y 60 d), y evaluar los cambios en su fertilidad en dos fechas posteriores a su incorporación. Diseño/metodología/aproximación: se probaron dos tratamientos de fertilización NPK 00-60-60 y 120-60-60 y un testigo. Al inicio del experimento, 15 y 30 d después de la cosecha e incorporación de la crotalaria, se tomaron muestras compuestas de suelo (0-30 cm) para analizarlas químicamente. Resultados: en peso seco (PS) total y de los componentes aéreos (tallo y hojas) de la crotalaria no hubo diferencias significativas entre tratamientos, su rendimiento promedio fue 7.08 y 7.16 t ha-1 para los cortes de 40 y 60 d respectivamente. El N tampoco mostró diferencias significativas entre dosis ni época de corte; su acumulación promedio fue de 151.61 y 176.37 kg ha-1 para los cortes respectivos. El P mostró valores más altos y diferencias significativas en los tratamientos fertilizados. El análisis del suelo antes de la siembra mostró propiedades óptimas, excepto por el bajo contenido de MO. Limitaciones del estudio/implicaciones: la sensibilidad de algunos de sus componentes puede dificultar la detección de cambios en la MO; siendo el COS un parámetro alternativo y fácilmente medible, aunque también es recomendable hacer un seguimiento a largo plazo. Hallazgos/conclusiones: la incorporación de crotalaria al suelo es una alternativa viable y promisoria para restituir el N utilizado e incorporar el del ambiente, además, la MO mejora su fertilidad física, química y biológica