A negative test of orbital control of geomagnetic reversals and excursions

A ~41 Kyr periodic component has been reported in some sedimentary paleointensity records, allowing speculation that there may be some component of orbital control of geomagnetic field generation such as by obliquity modulation. However, no discernable tendency is found for astronomically-dated geomagnetic reversals in the Plio-Pleistocene (0 to 5.3 Ma) or excursions in the Brunhes (0 to 0.78 Ma) to occur at a consistent amplitude or phase of obliquity cyclicity, nor of orbital eccentricity. An implication is that paleointensity lows which are characteristically associated with these features are not distributed in a systematic way relative to obliquity and eccentricity, supporting the idea that orbital forcing does not power the geodynamo

Apparent correlation of palaeomagnetic intensity and climatic records in deep-sea sediments

Most reports of a correlation between Pleistocene climate and geomagnetic field intensity rely strongly on the assumption that sediment natural remanent magnetic (NRM) intensity provides a record of geomagnetic field strength and is not sensitive to local changes in properties of the sediment. Critical assessment of relevant data presented here and elsewhere from deep-sea sediment cores shows that a pronounced dependence of NRM intensity on sediment composition can occur which implies that this assumption is unlikely to be generally valid. As sediment composition often reflects varying depositional conditions induced by climatic change, the significance of correlations proposed between Pleistocene palaeomagnetism and climatic indicators in deep-sea sediments may be less dramatic than sometimes supposed

La Nación, el peronismo y los orígenes de la Guerra fría en Argentina

This article deals with the international dimension of Argentine domestic policies by exploring one of the strategies of the conservative daily newspaper La Nación, between 1946 and 1950, in order to challenge Juan Perón’s hegemony. La Nación presented the Peronist regime as akin to the totalitarian regimes established under the Soviet Union’s vigilance. This is not surprising, but revealing the complex ideological mechanisms employed by La Nación in its strategy is a noteworthy endeavor. This work will provide a thorough exploration of the process through which La Nación shifted from its former opposition to Peronism, initially identified as a Nazi-Fascist movement, to a new articulation of the regime as a totalitarian one. To some extent this was not so different from the strategy that the United States’ (US) intellectual elites were carrying out in order to justify their struggle against a former ally in war as a continuation of purpose and not a rupture. Yet, the most interesting aspect of this evolution in the Argentine case is that it emerged in an autonomous way as a result of specific national and international phenomena. This shows that the characteristics of the early phase of the Cold War were shaped by transnational processes of convergence rather than US hegemony alone.Este artículo analiza la dimensión internacional de la política interna argentina explorando la estrategia del diario conservador La Nación, entre 1946 y 1950 en su enfrentamiento con el gobierno de Juan Domingo Perón. La Nación presentó el régimen peronista como similar a los regímenes totalitarios establecidos bajo el control de la Unión Soviética. Esto no resulta sorprendente, pero comprender los complejos mecanismos ideológicos empleados por La Nación en esta estrategia es un objetivo relevante de investigación. Este artículo ofrece un análisis detallado del proceso que permitió a La Nación transformar su descripción del peronismo como un movimiento nazi-fascista a otro totalitario. De alguna manera este proceso caminó en paralelo a la estrategia de los intelectuales estadounidenses para justificar el conflicto con un antiguo aliado como una continuación de los mismos objetivos de la Segunda Guerra Mundial y no como una ruptura. Sin embargo, lo más interesante es que en el caso argentino esta evolución surgió de manera autónoma como resultado de condiciones específicas nacional y de una particular interpretación de los fenómenos internacionales. Esto muestra que algunas características de la Guerra Fría temprana fueron moldeadas por procesos transnacionales de convergencia y no por la hegemonía de los Estados Unidos en solitario

Infrastructure for Detector Research and Development towards the International Linear Collider

The EUDET-project was launched to create an infrastructure for developing and testing new and advanced detector technologies to be used at a future linear collider. The aim was to make possible experimentation and analysis of data for institutes, which otherwise could not be realized due to lack of resources. The infrastructure comprised an analysis and software network, and instrumentation infrastructures for tracking detectors as well as for calorimetry.Comment: 54 pages, 48 picture

The time-averaged paleomagnetic field

We review indications of persistent deviations from the geocentric axial dipole model of the time-averaged geomagnetic field and present a zonal harmonic model derived from 185 deep-sea sediment piston cores taken from low to middle latitudes (to approximately ±45°). Analysis of the paleomagnetic inclination recorded in these cores for the Brunhes (normal polarity; 0-73 Ma) and Matuyama (reverse polarity; 0.73-2.47 Ma) chrons, after plate motion correction, gives well-constrained estimates of the dominant long-term nondipole contributions (the axial quadrupole and axial octupole) and shows no significant deviation from axial symmetry. The amplitude of the axial quadrupole is found to vary with polarity (2.6% of the geocentric axial dipole for normal; 4.6% for reverse), while the axial octupole does not show appreciable change (-2.9% for normal; -2.1% for reverse). These estimates of the quadrupole contribution agree well with prior determinations for the Plio-Pleistocene (0-5 Ma); however, the octupole contribution we find is opposite in sign to previous estimates. We suggest that a negative octupole is representative of the actual time-averaged paleomagnetic field, while prior positive octupole estimates probably reflect spurious inclination shallowing. The lack of polarity asymmetry in the octupole suggests that this nondipole component may be more closely linked to the main dipole field than is the quadrupole and so supports models of the geodynamo in which dipole and quadrupole families do not interact

Palaeomagnetic determination of emplacement temperature of Vesuvius AD 79 pyroclastic deposits

The city of Herculaneum was buried under 20 m of pyroclastic deposits during the AD 79 eruption of Vesuvius, whose crater is only 7 km to the east. These deposits have been interpreted as the deposits of mudflows or hot pyroclastic flows. Maury's studies of incinerated wood in Herculaneum demonstrate heating to at least 400° C. We have studied the variation of remanent magnetism with temperature for specimens taken from the deposits, including specimens of the matrix material and of embedded lithic fragments. We conclude that the temperature of the deposit at emplacement is unlikely to have been greater than 400° C, which further supports the interpretation of the pyroclastic deposits at Herculaneum as largely ignimbrites (hot pyroclastic flow deposits)

The view from everywhere: Disciplining diversity in post–World War II international social science

This paper explores the attempt of social scientists associated with Unesco to create a system of knowledge production to provide the international perspective necessary for democratic governance of a world community. Social scientists constructed a federal system of international associations that institutionalized American disciplines on an international scale. An international perspective emerged through the process of interdisciplinary international research. I call this ideal of coordinating multiple subjectivities to produce objectivity the “view from everywhere.” Influenced by social psychological “action-research,” collaborative research was group therapy. The attempt to operationalize internationalists' rallying slogan, “unity in diversity,” illuminated tensions inherent in the mobilization of science for social and political reform. © 2009 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64294/1/20394_ftp.pd

A simple rule to determine which insolation cycles lead to interglacials

The pacing of glacial–interglacial cycles during the Quaternary period (the past 2.6 million years) is attributed to astronomically driven changes in high-latitude insolation. However, it has not been clear how astronomical forcing translates into the observed sequence of interglacials. Here we show that before one million years ago interglacials occurred when the energy related to summer insolation exceeded a simple threshold, about every 41,000 years. Over the past one million years, fewer of these insolation peaks resulted in deglaciation (that is, more insolation peaks were ‘skipped’), implying that the energy threshold for deglaciation had risen, which led to longer glacials. However, as a glacial lengthens, the energy needed for deglaciation decreases. A statistical model that combines these observations correctly predicts every complete deglaciation of the past million years and shows that the sequence of interglacials that has occurred is one of a small set of possibilities. The model accounts for the dominance of obliquity-paced glacial–interglacial cycles early in the Quaternary and for the change in their frequency about one million years ago. We propose that the appearance of larger ice sheets over the past million years was a consequence of an increase in the deglaciation threshold and in the number of skipped insolation peaks.P.C.T. acknowledges funding from a Leverhulme Trust Research Project Grant (RPG-2014-417). M.C. and T.M. acknowledge support from the Belgian Policy Office under contract BR/121/A2/STOCHCLIM. E.W.W. is funded under a Royal Society Research Professorship and M.C. is a senior research scientist with the Belgian National Fund of Scientific Research