Gravity potential spherical harmonic series

Time variable gravity fields, reflecting variations of mass distribution in the system Earth is one of the key parameters to understand the changing Earth. Mass variations are caused either by redistribution of mass in, on or above the Earth's surface or by geophysical processes in the Earth's interior. The first set of observations of monthly variations of the Earth gravity field was provided by the US/German GRACE satellite mission beginning in 2002. This mission is still providing valuable information to the science community. However, as GRACE has outlived its expected lifetime, the geoscience community is currently seeking successor missions in order to maintain the long time series of climate change that was begun by GRACE. Several studies on science requirements and technical feasibility have been conducted in the recent years. These studies required a realistic model of the time variable gravity field in order to perform simulation studies on sensitivity of satellites and their instrumentation. This was the primary reason for the European Space Agency (ESA) to initiate a study on ''Monitoring and Modelling individual Sources of Mass Distribution and Transport in the Earth System by Means of Satellites''. The goal of this interdisciplinary study was to create as realistic as possible simulated time variable gravity fields based on coupled geophysical models, which could be used in the simulation processes in a controlled environment. For this purpose global atmosphere, ocean, continental hydrology and ice models were used. The coupling was performed by using consistent forcing throughout the models and by including water flow between the different domains of the Earth system. In addition gravity field changes due to solid Earth processes like continuous glacial isostatic adjustment (GIA) and a sudden earthquake with co-seismic and post-seismic signals were modelled. All individual model results were combined and converted to gravity field spherical harmonic series, which is the quantity commonly used to describe the Earth's global gravity field. The result of this study is a twelve-year time-series of 6-hourly time variable gravity field spherical harmonics up to degree and order 180 corresponding to a global spatial resolution of 1 degree in latitude and longitude. In this paper, we outline the input data sets and the process of combining these data sets into a coherent model of temporal gravity field changes. The resulting time series was used in some follow-on studies and is available to anybody interested.

Diatom events and Neogene nannofossils of ODP Hole 201-1225A

Shipboard investigation of magnetostratigraphy and shore-based investigation of diatoms and calcareous nannofossils were used to identify datum events in sedimentary successions collected at Ocean Drilling Program (ODP) Leg 201 Site 1225. The goal was to extend the magnetic record previously studied at the same site, ODP Leg 138 Site 851, and provide a comprehensive age model for Site 1225. Two high-magnetic intensity zones at 0-70 and 200-255 meters below seafloor (mbsf) were correlated with lithologic Subunits IA and IC in Hole 1225A. Subunit IA (0-70 mbsf) contains the magnetic reversal record until the Cochiti Subchronozone (3.8 Ma) and has a sedimentation rate of 1.7 cm/k.y. This agrees with previous work done at Site 851. Subunit IC (200-255 mbsf) was not sampled at Site 851. Diatom and nannofossil biostratigraphy constrained this subunit, and we found it to contain the magnetic reversal record between Subchrons C4n.2r and C5n.2n (8.6-9.7 Ma), yielding a sedimentation rate of 2.7 cm/k.y. Biostratigraphy was used to establish the sedimentation rates within Subunits IB and ID (70-200 mbsf and 255-300 mbsf, respectively). These subunits had higher sedimentation rates (~3.4 cm/k.y.) and coincide with the late Miocene-early Pliocene biogenic bloom event (4.5-7 Ma) and the Miocene global cooling trend (10-15 Ma). High biogenic productivity associated with these subunits resulted in the pyritization of the magnetic signal. In lithologic Subunit ID, basement flow is another factor that may be altering the magnetic signal; however, the good correlation between the biostratigraphy and magnetostratigraphy indicates that the magnetic record was locked-in near the seafloor and suggests the age model is robust.

Da informação nossa de cada dia à Ciência da Informação : Conceitos, história, teorias e questões recentes

The work has as objective to produce a look about what we can think as a long history of information, what we think out from the most remote times until its conversion to theástatusáof object of the Information Science (IS) in the second half of 20th century. Of theorical nature and keeping up itself by the literature in IS and in similar areas, a discussion is made about the concept of information to then to list names, happenings and theories that contributed in the passage of the domain of the daily life to the domain of the Science. From a distant past to the most recent happenings connected to the problem of the privacity of the citizens in the digital networks, it is verified in the history of information a closed relation with the power, reason that suggests the deepening of the studies in IS about the political and ethical issues in the contemporary society.

Las trayectorias académicas : Una nueva mirada sobre los profesores de la Facultad de Filosofía y Letras durante el peronismo

Este trabajo tiene el propósito de presentar los aportes teórico-metodológicos de un estudio sobre redes y trayectorias del cuerpo de profesores de la Facultad de Filosofía y Letras de la Universidad de Buenos Aires, durante el período 1943-1955. El examen de las trayectorias docentes permite de algún modo, dar cuenta de diferentes recorridos académicos en el campo universitario con cierta independencia de las circunstancias políticas. Asimismo posibilita poner en evidencia trayectorias ciertamente similares entre quienes quedaron fuera de la universidad y quienes conservaron o asumieron su cargo en un período de fuertes antagonismos. Nuestra propuesta apunta a introducir en el debate los posibles alcances y límites del análisis de las fuentes documentales aquí presentadas a través del enfoque de redes y trayectorias para caracterizar la universidad durante el peronismo, y en este sentido contribuir a la comprensión de este fenómeno complejo y heterogéneo

¿Para qué educar en ciencias naturales, ambiente y salud hoy en Argentina?

Este artículo presenta un análisis de representaciones sociales (RS) sobre finalidades de la educación en ciencias naturales y rol docente, enmarcado en una experiencia de formación en servicio y trabajo colaborativo con docentes de diferentes niveles educativos de la Provincia de Buenos Aires. Las RS del rol docente mostraron las dimensiones vocacional, profesional y política. La última emergió con fuerza en innovaciones que implicaron procesos concretos de participación ciudadana con estudiantes. Como finalidades aparecieron diferentes aspectos de las RS: formación para la ciudadanía, ciencia como cultura, ciencia útil para la vida cotidiana, propedéutica y alfabetización científica. Estos hallazgos se contrastan con documentos curriculares y propuestas de teóricos de la educación en ciencias naturales

Temas y problemas. Métodos, técnicas e instrumentos : Una escala para estudiar los estilos de aprendizaje en los niños

Fil: Agudo de Córsico, María Celia Mercedes. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Da informação nossa de cada dia à Ciência da Informação : Conceitos, história, teorias e questões recentes

The work has as objective to produce a look about what we can think as a long history of information, what we think out from the most remote times until its conversion to theástatusáof object of the Information Science (IS) in the second half of 20th century. Of theorical nature and keeping up itself by the literature in IS and in similar areas, a discussion is made about the concept of information to then to list names, happenings and theories that contributed in the passage of the domain of the daily life to the domain of the Science. From a distant past to the most recent happenings connected to the problem of the privacity of the citizens in the digital networks, it is verified in the history of information a closed relation with the power, reason that suggests the deepening of the studies in IS about the political and ethical issues in the contemporary society.