9,859 research outputs found
Geomorfología litoral y significación de las variacones del nivel del mar
Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu
A Derivation of Three-Dimensional Inertial Transformations
The derivation of the transformations between inertial frames made by
Mansouri and Sexl is generalised to three dimensions for an arbitrary direction
of the velocity. Assuming lenght contraction and time dilation to have their
relativistic values, a set of transformations kinematically equivalent to
special relativity is obtained. The ``clock hypothesis'' allows the derivation
to be extended to accelerated systems. A theory of inertial transformations
maintaining an absolute simultaneity is shown to be the only one logically
consistent with accelerated movements. Algebraic properties of these
transformations are discussed. Keywords: special relativity, synchronization,
one-way velocity of light, ether, clock hypothesis.Comment: 16 pages (A5), Latex, one figure, to be published in Found. Phys.
Lett. (1997
Instrumentation for Millimeter-wave Magnetoelectrodynamic Investigations of Low-Dimensional Conductors and Superconductors
We describe instrumentation for conducting high sensitivity millimeter-wave
cavity perturbation measurements over a broad frequency range (40-200 GHz) and
in the presence of strong magnetic fields (up to 33 tesla). A Millimeter-wave
Vector Network Analyzer (MVNA) acts as a continuously tunable microwave source
and phase sensitive detector (8-350 GHz), enabling simultaneous measurements of
the complex cavity parameters (resonance frequency and Q-value) at a rapid
repetition rate (approx. 10 kHz). We discuss the principal of operation of the
MVNA and the construction of a probe for coupling the MVNA to various
cylindrical resonator configurations which can easily be inserted into a high
field magnet cryostat. We also present several experimental results which
demonstrate the potential of the instrument for studies of low-dimensional
conducting systems.Comment: 20 pages including fig
Análisis de secuencias de islas barrera pleistocenas en relación con variaciones del nivel del mar, laguna de La Mata (Alicante)
En la laguna de La Mata (Alicante) se estudia un complejo de cordones litorales pleistocenos que forman el cierre de la actual laguna. Se analizan las secuencias resultantes y los posibles indicadores de variaciones del nivel del mar. Asimismo se interpretan estos depósitos en base a una curva aparente de tendencias del nivel del mar, obtenida con la suma de las componentes eustáticas cíclicas y la componente relativa debida al factor tectónico aplicado.
[ABSTRACT]
A complex of Pleistocene coastal barriers is studied in La Mata lagoon (Alicante). The resuting sequences are analyzed in order to establish indicators 0f sea level changes. These deposits can be correlated with an apparent curve of sea level tendencies obtained with the sum of the cyclic eustatic component and the relative component due to the tectonic factor applied
Holocene aeolian phases and human settlements along the Atlantic coast of southern Spain
A combined geomorphological, radiocarbon dating, archaeological and historical approach permits
a refining of the age of the coastal dune systems related to estuaries in the Gulf of Cadiz. Three dune systems
are distinguished in this paper. The oldest one, DI, which accumulated under prevailing WSW winds during
the first millennium BC, overlays both the occupational horizons of Late Neolithic-Early Copper Age (fourth
millennium BC) and the 'lithic workshop levels' (fourth to second millennia BC). The middle dune system, D2,
containing both Roman and medieval remains, accumulated between the thirteenth or fourteenth centuries and
the seventeenth century AD. The youngest D3 system is associated with the time of building of watchtowers
in the seventeenth century AD but extends to the present; it is related to SW prevailing winds. We explain the
absence of aeolian deposits prior to ~2700 cal. BP as the result of trapping of a large part of the sediment
supply in the estuaries, which starved the neighbouring beaches and aeolian settings. Aeolian accumulation
reached significant values when sedimentation in the coastal zone changed from being mainly aggradational
in the estuaries (~6500~2700 cal. BP) to mainly progradational in spit barriers and related dunes (post ~2700
cal. BP). The present analysis of aeolian systems suggests a non-direct correlation, at least in some cases,
between coastal progradation of spit barriers and aridity
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