873 resultados para History of Roundtable


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Pacing of the marine carbon cycle by orbital forcing during the Pliocene and Pleistocene Ice Ages [past 2.5 million years (Myr)] is well known. As older deep-sea sediment records are being studied at greater temporal resolution, it is becoming clear that similar fluctuations in the marine carbon system have occurred throughout the late Mesozoic and Tertiary, despite the absence of large continental ice sheets over much of this time. Variations in both the organic and the calcium carbonate components of the marine carbon system seem to have varied cyclically in response to climate forcing, and carbon and carbonate time series appear to accurately characterize the frequency spectrum of ancient climatic change. For the past 35 Myr, much of the variance in carbonate content carries the “polar” signal of obliquity [41,000 years (41 kyr)] forcing. Over the past 125 Myr, there is evidence from marine sediments of the continued role of precessional (≈21 kyr) climatic cycles. Repeat patterns of sedimentation at about 100, 400, and 2,400 kyr, the modulation periods of precession, persistently enter into marine carbon cycle records as well. These patterns suggest a nonlinear response of climate and/or the sedimentation of organic carbon and carbonates to precessional orbital perturbations. Nonlinear responses of the carbon system may help to amplify relatively weak orbital insolation anomalies into more significant climatic perturbations through positive feedback effects. Nonlinearities in the carbon cycle may have transformed orbital-climatic cycles into long-wavelength features on time scales comparable to the residence times of carbon and nutrient elements in the ocean.

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Although the prevalence or even occurrence of insect herbivory during the Late Carboniferous (Pennsylvanian) has been questioned, we present the earliest-known ecologic evidence showing that by Late Pennsylvanian times (302 million years ago) a larva of the Holometabola was galling the internal tissue of Psaronius tree-fern fronds. Several diagnostic cellular and histological features of these petiole galls have been preserved in exquisite detail, including an excavated axial lumen filled with fecal pellets and comminuted frass, plant-produced response tissue surrounding the lumen, and specificity by the larval herbivore for a particular host species and tissue type. Whereas most suggestions over-whelmingly support the evolution of such intimate and reciprocal plant-insect interactions 175 million years later, we provide documentation that before the demise of Pennsylvanian age coal-swamp forests, a highly stereotyped life cycle was already established between an insect that was consuming internal plant tissue and a vascular plant host responding to that herbivory. This and related discoveries of insect herbivore consumption of Psaronius tissues indicate that modern-style herbivores were established in Late Pennsylvanian coal-swamp forests.

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The life history of Harpegnathos saltator is exceptional among ants because both queens and workers reproduce sexually. Recently mated queens start new colonies alone, but later some of the offspring workers also become inseminated and take over the egg-laying role. This alternation seems associated with the existence of very complex underground nests, which are designed to survive floods. Longevity of ponerine queens is low (a consequence of limited caste dimorphism in this "primitive" subfamily), and upon the death of an H. saltator foundress, the nest represents a substantial investment. The queen's progeny should thus be strongly selected to retain the valuable nests. Unlike the flying queens, the workers copulate with males from their own colonies, and, thus, their offspring are expected to be highly related to the foundress. Colony fission appears not to occur because a daughter fragment would lack an adequate nest for protection. Thus, the annual production of queens in colonies with reproductive workers remains essential for the establishment of new colonies. This contrasts with various other ponerine species in which the queens no longer exist.

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We have studied the radial structure of the stellar mass surface density (μ∗) and stellar population age as a function of the total stellar mass and morphology for a sample of 107 galaxies from the CALIFA survey. We applied the fossil record method based on spectral synthesis techniques to recover the star formation history (SFH), resolved in space and time, in spheroidal and disk dominated galaxies with masses from 10^9 to 10^12 M_⊙. We derived the half-mass radius, and we found that galaxies are on average 15% more compact in mass than in light. The ratio of half-mass radius to half-light radius (HLR) shows a dual dependence with galaxy stellar mass; it decreases with increasing mass for disk galaxies, but is almost constant in spheroidal galaxies. In terms of integrated versus spatially resolved properties, we find that the galaxy-averaged stellar population age, stellar extinction, and μ_∗ are well represented by their values at 1 HLR. Negative radial gradients of the stellar population ages are present in most of the galaxies, supporting an inside-out formation. The larger inner (≤1 HLR) age gradients occur in the most massive (10^11 M_⊙) disk galaxies that have the most prominent bulges; shallower age gradients are obtained in spheroids of similar mass. Disk and spheroidal galaxies show negative μ∗ gradients that steepen with stellar mass. In spheroidal galaxies, μ∗ saturates at a critical value (~7 × 10^2 M_⊙/pc^2 at 1 HLR) that is independent of the galaxy mass. Thus, all the massive spheroidal galaxies have similar local μ_∗ at the same distance (in HLR units) from the nucleus. The SFH of the regions beyond 1 HLR are well correlated with their local μ_∗, and follow the same relation as the galaxy-averaged age and μ_∗; this suggests that local stellar mass surface density preserves the SFH of disks. The SFH of bulges are, however, more fundamentally related to the total stellar mass, since the radial structure of the stellar age changes with galaxy mass even though all the spheroid dominated galaxies have similar radial structure in μ_∗. Thus, galaxy mass is a more fundamental property in spheroidal systems, while the local stellar mass surface density is more important in disks.

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Using a compilation of 379 massive (stellar mass M ≳ 10^11 M_⊙) spheroid-like galaxies from the near-infrared Palomar/DEEP-2 survey, we investigated, up to z ∼ 1, whether the presence of companions depends on the size of the host galaxy. We explored the presence of companions for mass ratios with respect to the central massive galaxy down to 1 : 10 and 1 : 100, and within projected distances of 30, 50 and 100 kpc of these objects. We found evidence that these companions are equally distributed around both compact and extended massive spheroid-like galaxies. This suggests that, at least since z ∼ 1, the merger activity in these objects is nearly homogeneous across the whole population and that the merger history is not affected by the size of the host galaxy. Our results could indicate that compact and extended massive spheroid-like galaxies are increasing in size at the same rate.

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Previous research shows that during the period of Japanese American internment gardening became a popular activity for the interned. Primarily approached historically, little work has been conducted to archaeologically analyze the efforts of landscaping by former internees. Gardening activity can paint a better picture of Japanese American identity during the period of forced confinement. This research investigates internee gardens methodologically through surface survey, ground penetrating radar, excavation, oral history, soil chemistry, archaeobotany, and palynology. The thorough investigation of landscaping efforts of internees builds upon knowledge of expression within Japanese American relocation centers, as well as the understanding of a lineage of gardening as Japanese immigrant tradition. Using available materials, gardeners adapted both tradition and environment for the purpose of improving conditions under internment and maintaining an affiliation to heritage. My examination of internee landscaping better explains how many collectively maintained, adapted, and publicly expressed an ethnic identity.

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This article advocates for a fundamental re-understanding about the way that the history of race is understood by the current Supreme Court. Represented by the racial rights opinions of Justice John Roberts that celebrate racial progress, the Supreme Court has equivocated and rendered obsolete the historical experiences of people of color in the United States. This jurisprudence has in turn reified the notion of color-blindness, consigning racial discrimination to a distant and discredited past that has little bearing to how race and inequality is experienced today. The racial history of the Roberts Court is centrally informed by the context and circumstances surrounding Brown v. Board of Education. For the Court, Brown symbolizes all that is wrong with the history of race in the United States - legal segregation, explicit racial discord, and vicious and random acts of violence. Though Roberts Court opinions suggest that some of those vestiges still exits, the bulk of its jurisprudence indicate the opposite. With Brown’s basic factual premises as its point of reference, the Court has consistently argued that the nation has made tremendous strides away from the condition of racial bigotry, intolerance, and inequity. The article accordingly argues that the Roberts Court reliance on Brown to understand racial progress is anachronistic. Especially as the nation’s focus for racial inequality turned national in scope, the same binaries in Brown that had long served to explain the history of race relations in the United States (such as Black-White, North-South, and Urban-Rural) were giving way to massive multicultural demographic and geographic transformations in the United States in the years and decades after World War II. All of the familiar tropes so clear in Brown and its progeny could no longer fully describe the current reality of shifting and transforming patterns of race relations in the United States. In order to reclaim the history of race from the Roberts Court, the article assesses a case that more accurately symbolizes the recent history and current status of race relations today: Keyes v. School District No. 1. This was the first Supreme Court case to confront how the binaries of cases like Brown proved of little probative value in addressing how and in what ways race and racial discrimination was changing in the United States. Thus, understanding Keyesand the history it reflects reveals much about how and in what ways the Roberts Court should rethink its conclusions regarding the history of race relations in the United States for the last 60 years.

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The aim of this article is to highlight the importance of the history of public health for public health research and practice itself. After summarily reviewing the current great vitality of the history of collective health oriented initiatives, we explain three particular features of the historical vantage point in public health, namely the importance of the context, the relevance of a diachronic attitude and the critical perspective. In order to illustrate those three topics, we bring up examples taken from three centuries of fight against malaria, the so called “re-emerging diseases” and the 1918 influenza epidemic. The historical approach enriches our critical perception of the social effects of initiatives undertaken in the name of public health, shows the shortcomings of public health interventions based on single factors and asks for a wider time scope in the assessment of current problems. The use of a historical perspective to examine the plurality of determinants in any particular health condition will help to solve the longlasting debate on the primacy of individual versus population factors, which has been particularly intense in recent times.

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This article is the English version of “Traductoras gallegas del siglo XX: Reescribiendo la historia de la traducción desde el género y la nación” by Olga Castro. It was not published on the print version of MonTI for reasons of space. The online version of MonTI does not suffer from these limitations, and this is our way of promoting plurilingualism.

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This article is the English version of “Examen crítico de la bibliografía sobre la historia de la traducción en España” by David Pérez Blázquez. It was not published on the print version of MonTI for reasons of space. The online version of MonTI does not suffer from these limitations, and this is our way of promoting plurilingualism.