Violencia e invisibilidad indígena : La cuestión de los pueblos originarios durante el primer peronismo

El presente trabajo busca profundizar en el análisis de los vínculos existentes entre el primer gobierno peronista y la cuestión indígena, centrándose en las políticas gubernamentales desarrolladas por el gobierno de Perón frente a dos fuertes conflictos violentos que tuvieron lugar entre 1946 y 1947: el "Malón de la paz", la movilización indígena llevada a cabo entre mayo y agosto de 1947, cuando 174 kollas caminaron 2000 kilómetros desde la Puna y el valle de Orán hasta la Capital Federal para reclamar por la titularidad de sus tierras, en manos de terratenientes y en denuncia de las condiciones de explotación en las que trabajaban; y "Masacre de Rincón Bomba", el conflicto desarrollado en una pequeña localidad de Formosa, cuando indígenas de comunidades wichi, tobas y principalmente pilagás fueron masacradas por la Gendarmería Nacional en un confuso episodio, que sale a la luz hace pocos años. El objetivo en ambos puntos es doble: por un lado analizar la relación entre los intereses e intenciones del gobierno de Juan Domingo Perón para con las comunidades originarias, visibilizando su existencia y sus condiciones de vida en tanto sujetos de derechos históricamente vulnerados. Por otro, abrir el debate historiográfico sobre el quehacer de los historiadores respecto de una temática que ha sido silenciada durante décadas, negando la existencia y la identidad de los pueblos originarios

Countering cooperative effects in protease inhibitors using constrained b-strand-mimicking templates in focused combinatorial libraries

A major problem in de novo design of enzyme inhibitors is the unpredictability of the induced fit, with the shape of both ligand and enzyme changing cooperatively and unpredictably in response to subtle structural changes within a ligand. We have investigated the possibility of dampening the induced fit by using a constrained template as a replacement for adjoining segments of a ligand. The template preorganizes the ligand structure, thereby organizing the local enzyme environment. To test this approach, we used templates consisting of constrained cyclic tripeptides, formed through side chain to main chain linkages, as structural mimics of the protease-bound extended beta-strand conformation of three adjoining amino acid residues at the N- or C-terminal sides of the scissile bond of substrates. The macrocyclic templates were derivatized to a range of 30 structurally diverse molecules via focused combinatorial variation of nonpeptidic appendages incorporating a hydroxyethylamine transition-state isostere. Most compounds in the library were potent inhibitors of the test protease (HIV-1 protease). Comparison of crystal structures for five protease-inhibitor complexes containing an N-terminal macrocycle and three protease-inhibitor complexes containing a C-terminal macrocycle establishes that the macrocycles fix their surrounding enzyme environment, thereby permitting independent variation of acyclic inhibitor components with only local disturbances to the protease. In this way, the location in the protease of various acyclic fragments on either side of the macrocyclic template can be accurately predicted. This type of templating strategy minimizes the problem of induced fit, reducing unpredictable cooperative effects in one inhibitor region caused by changes to adjacent enzyme-inhibitor interactions. This idea might be exploited in template-based approaches to inhibitors of other proteases, where a beta-strand mimetic is also required for recognition, and also other protein-binding ligands where different templates may be more appropriate.

Moreton Bay, Queensland, Australia: An example of the co-existence of significant marine mammal populations and large-scale coastal development

Recent analyses assert that large marine vertebrates such as marine mammals are now 'functionally or entirely extinct in most coastal ecosystems'. Moreton Bay is a large diverse marine ecosystem bordering the fastest growing area in Australia. The human population is over 1.6 million and increasing yearly by between 10% and 13% with resultant impacts upon the adjoining marine environment. Nonetheless, significant populations of three species of marine mammals are resident within Moreton Bay and a further 14 species are seasonal or occasional visitors. This paper reviews the current and historical distributions and abundance of these species in the context of the current management regime and suggests initiatives to increase the resilience of marine mammal populations to the changes wrought by the burgeoning human population in coastal environments. (C) 2004 Elsevier Ltd. All rights reserved.

Tidal impacts on riparian salinities near estuaries

Groundwater-dependent riparian biota is known to be sensitive to changes in soil and groundwater salinity in estuarine systems. The groundwater flow and salinity behaviour in a phreatic aquifer adjoining a partially penetrating, tidal. estuary is investigated through two-dimensional numerical experiments for a lateral cross-section, which explore the influence of factors, such as aquifer and soil materials, tidal amptitudes, and regional groundwater hydraulic gradients. The density contrast between estuarine water and the fresh groundwater drives saltwater penetration of the aquifer even in the case of a marked groundwater hydraulic gradient towards the estuary. We show that tidal fluctuations in estuaries can significantly affect the groundwater salinity distribution in adjacent density-stratified phreatic aquifers. This has consequences for the expected distribution of salinity-sensitive biota in the hyporheic zone as well as vegetation and fauna dependent on water in the riparian soil and aquifer. The shape of the dense saltwater wedge propagating into the adjacent groundwater system is also modified by the estuarine tidal signal, although this effect appears to have only minor influence on the maximum distance penetrated into the aquifer (i.e., location of the 'toe' of the wedge). Tide-induced changes to riparian groundwater salinity are advection-driven, as evidenced by the modified time-averaged groundwater flow dynamics. (c) 2006 Elsevier B.V. All rights reserved.

O DIREITO É TORCIDO À PORTA PORQUE A JUSTIÇA SE ENCONTRA DEITADA POR TERRA: Um estudo sobre o direito e a justiça na profecia de Amós, a partir de Am 5,10-13

O trabalho que tem por título: O Direito é torcido à Porta porque a Justiça se encontra deitada por terra é um exercício exegético que tem por objeto a perícope Am 5,10-13. Na análise semântica dos seus principais vocábulos evidenciou-se uma realidade social, política e econômica paradoxal em Israel, sob o comando de Jeroboão II (787-747 a.C.), como resultado de uma expansão territorial e comercial, de vitórias militares e da organização de um Estado tributarista. Esse modelo de sociedade gerou um antagonismo social entre uma elite abastada que esbanjava luxo e ostentação, à custa do suor e da fome de uma população empobrecida, especialmente a classe camponesa, que trabalhava para sustentar as benesses do mundo urbano. É de dentro dessa realidade que ecoa o grito de Amós como denúncia a esse estado de coisas, como palavra de desgraça e condenação a toda sorte de desmandos praticados em Israel. Entre esses a falência do sistema judiciário, pela prática da exploração e corrupção por parte dos magistrados, de ricos comerciantes e latifundiários, desviando o pobre do seu direito de recorrer em sua defesa perante o tribunal. Em razão disso, Amós anuncia a ruína de Israel, com o Dia de Javé, que será um anti-Êxodo, e aponta uma exigência ético-religiosa como forma de reverter esse não futuro para Israel, que se traduz no compromisso de estabelecer à Porta o Direito e a Justiça.

Simulating the value of collaboration in multi-actor conservation planning

The loss of habitat and biodiversity worldwide has led to considerable resources being spent for conservation purposes on actions such as the acquisition and management of land, the rehabilitation of degraded habitats, and the purchase of easements from private landowners. Prioritising these actions is challenging due to the complexity of the problem and because there can be multiple actors undertaking conservation actions, often with divergent or partially overlapping objectives. We use a modelling framework to explore this issue with a study involving two agents sequentially purchasing land for conservation. We apply our model to simulated data using distributions taken from real data to simulate the cost of patches and the rarity and co-occurence of species. In our model each agent attempted to implement a conservation network that met its target for the minimum cost using the conservation planning software Marxan. We examine three scenarios where the conservation targets of the agents differ. The first scenario (called NGO-NGO) models the situation where two NGOs are both are targeting different sets of threatened species. The second and third scenarios (called NGO-Gov and Gov-NGO, respectively) represent a case where a government agency attempts to implement a complementary conservation network representing all species, while an NGO is focused on achieving additional protection for the most endangered species. For each of these scenarios we examined three types of interactions between agents: i) acting in isolation where the agents are attempting to achieve their targets solely though their own actions ii) sharing information where each agent is aware of the species representation achieved within the other agent’s conservation network and, iii) pooling resources where agents combine their resources and undertake conservation actions as a single entity. The latter two interactions represent different types of collaborations and in each scenario we determine the cost savings from sharing information or pooling resources. In each case we examined the utility of these interactions from the viewpoint of the combined conservation network resulting from both agents' actions, as well as from each agent’s individual perspective. The costs for each agent to achieve their objectives varied depending on the order in which the agents acted, the type of interaction between agents, and the specific goals of each agent. There were significant cost savings from increased collaboration via sharing information in the NGO-NGO scenario were the agent’s representation goals were mutually exclusive (in terms of specie targeted). In the NGO-Gov and Gov-NGO scenarios, collaboration generated much smaller savings. If the two agents collaborate by pooling resources there are multiple ways the total cost could be shared between both agents. For each scenario we investigate the costs and benefits for all possible cost sharing proportions. We find that there are a range of cost sharing proportions where both agents can benefit in the NGO-NGO scenarios while the NGO-Gov and Gov-NGO scenarios again showed little benefit. Although the model presented here has a range of simplifying assumptions, it demonstrates that the value of collaboration can vary significantly in different situations. In most cases, collaborating would have associated costs and these costs need to be weighed against the potential benefits from collaboration. The model demonstrates a method for determining the range of collaboration costs that would result in collaboration providing an efficient use of scarce conservation resources.

Multiple conduction paths in boron δ-doped diamond structures

Impedance spectroscopy has been used to investigate conductivity within boron-doped diamond in an intrinsic/delta-doped/intrinsic (i-d-i) multilayer structure. For a 5 nm thick delta layer, three conduction pathways are observed, which can be assigned to transport within the delta layer and to two differing conduction paths in the i-layers adjoining the delta layer. For transport in the i-layers, thermal trapping/detrapping processes can be observed, and only at the highest temperature investigated (673 K) can transport due to a single conduction process be seen. Impedance spectroscopy is an ideal nondestructive tool for investigating the electrical characteristics of complex diamond structures.

Optic disc haemorrhage audit

Poster section INTRODUCTION. Retrospective Analysis PURPOSE. To evaluate the morphology and location of optic disc haemorrhages (ODH) identified at diabetic retinopathy (DR) screening to establish whether particular ODH are predictive of ocular disease (e.g. glaucoma). METHODS. Retrospective analysis of 77 patients who presented with ODH at DR screening in the Birmingham and Black Country screening programme between June 2009-March 2010. Mean age was 71 years (range 39-89). Cup/disc ratio (CDR), location and morphology of the haemorrhage were recorded. The outcome of the referral and the status of the ODH were followed up a year later. RESULTS. Of the 77 referred, 34 patients were unassessed for possible glaucoma. Of the 43 patients that were assessed in the hospital eye service for glaucoma, 11 (26%) were diagnosed with glaucoma. These glaucoma patients mostly presented with flame haemorrhages (64%) and blot haemorrhages (36%). Haemorrhages tended to adjoin the margin of the OD (64%), and were more commonly flame shaped (64%). They less commonly occurred in the optic disc itself (36%), and were all blot shaped. The OD Cup/disc ratio (CDR) of the patients with glaucoma (n=11) ranged from 0.33-0.57. It is interesting to note the highest CDR was 0.68 in the 77 patients referred. 32 patients were confirmed as not having glaucoma. 24 (75%) of these patients presented with an ODH adjoining the margin, of which 20 (83%) were flame, and 4 blot (17%) shaped. Only 8 (25%) presented with an ODH in the OD, of which 6 (75%) were blot shaped. One year follow up of the 77 referred cases revealed that the ODH resolved in 45 (57%) patients while 10 (13%) still had an ODH present. 15 (21%) were still under ophthalmology hence digital retinal photos were not available for assessment. Six patients (8%) (age range 71-91 years) died within the year, and one lost to follow up. CONCLUSIONS. The results suggest that a significant number of patients with ODH have glaucoma and that the differing morphology of the haemorrhage is not a major predictor i.e. blot versus flame shaped, adjoining or in the optic disc. The cup/disc ratio did not predict glaucoma either.

Respiratory function monitoring using a real-time three-dimensional fiber-optic shaping sensing scheme based upon fiber Bragg gratings

An array of in-line curvature sensors on a garment is used to monitor the thoracic and abdominal movements of a human during respiration. The results are used to obtain volumetric changes of the human torso in agreement with a spirometer used simultaneously at the mouth. The array of 40 in-line fiber Bragg gratings is used to produce 20 curvature sensors at different locations, each sensor consisting of two fiber Bragg gratings. The 20 curvature sensors and adjoining fiber are encapsulated into a low-temperature-cured synthetic silicone. The sensors are wavelength interrogated by a commercially available system from Moog Insensys, and the wavelength changes are calibrated to recover curvature. A three-dimensional algorithm is used to generate shape changes during respiration that allow the measurement of absolute volume changes at various sections of the torso. It is shown that the sensing scheme yields a volumetric error of 6%. Comparing the volume data obtained from the spirometer with the volume estimated with the synchronous data from the shape-sensing array yielded a correlation value 0.86 with a Pearson's correlation coefficient p <0.01.

Respiratory function monitoring using a real-time three-dimensional fiber-optic shaping sensing scheme based upon fiber Bragg gratings

An array of in-line curvature sensors on a garment is used to monitor the thoracic and abdominal movements of a human during respiration. The results are used to obtain volumetric changes of the human torso in agreement with a spirometer used simultaneously at the mouth. The array of 40 in-line fiber Bragg gratings is used to produce 20 curvature sensors at different locations, each sensor consisting of two fiber Bragg gratings. The 20 curvature sensors and adjoining fiber are encapsulated into a low-temperature-cured synthetic silicone. The sensors are wavelength interrogated by a commercially available system from Moog Insensys, and the wavelength changes are calibrated to recover curvature. A three-dimensional algorithm is used to generate shape changes during respiration that allow the measurement of absolute volume changes at various sections of the torso. It is shown that the sensing scheme yields a volumetric error of 6%. Comparing the volume data obtained from the spirometer with the volume estimated with the synchronous data from the shape-sensing array yielded a correlation value 0.86 with a Pearson's correlation coefficient p <0.01.

The Romanian Orthodox Church

At first glance, the nationalist ideology of the French Revolution seems to have had little impact on the Orthodox Church in Romanian-speaking territories. Romanians were the predominant inhabitants of the principalities of Wallachia and Moldavia and the neighboring territories of Transylvania (including Crişana, Maramureş and Banat), Bukovina, Bessarabia, and Dobrudja. The majority of ethnic Romanians belonged to the Orthodox faith while their communities were at the intersection of geopo liti cal interests of the Rus sian, Ottoman, and Habsburg empires. In 1859 the Principalities of Wallachia and Moldavia (known as the Old Kingdom between 1866 and 1918) united into a single state under the rule of a local prince. The term "Romania" began to be used by the new state in its of cial documents in 1862. Two years later, the state supported the declaration of a Romanian autocephalous (in de pen dent) church that was recognized by the Ecumenical Patriarchate in 1885. As an integrative part of the Orthodox commonwealth, the church was situated between the competing jurisdictions of the Ecumenical Patriarchate and the Rus sian Orthodox Church, while its declaration of autocephaly followed a pattern in the spread of national churches in Southeastern Europe. From the Treaty of Kuchuk Kainardji of 1774 to the beginning of the Greek War for In de pen dence in 1821, the Romanian principalities were under the suzerainty of the Ottoman Empire, which had full control of their po liti cal and economic affairs. The sultan appointed princes, and the Porte determined their po liti cal and judicial status. The princes were drawn from the "Phanariots," and were directly appointed by the Porte from preponderantly Greek elite rather than the Romanian local elite, the boyars (boieri).1 In each principality, the church was headed by a metropolitan who was under the direct jurisdiction of the Ecumenical Patriarchate. That religion mattered to local population as a means of social cohesion was suggestively depicted by Anatole de Demidoff, an En glish traveler in the region in 1837. Arriving in Bucharest, the capital of Wallachia, he claimed that: I know of no city in Europe in which it is possible to find more agreeable society, or in which there is a better tone, united with the most charming gaiety⋯. Religion, which is here of the schismatic Greek creed, does not, properly speaking, hold any great empire over the minds of the Wallachian people, but they observe its outward forms, and particularly the austerities of fasting, with scrupulous exactitude. The people are seen to attend divine ser vice with every sign of respect, and the great number of churches existing in Wallachia, bear witness to the ardent zeal with which outward worship is honored.2 The Romanian Orthodox Church was a national institution, closely linked to social, economic, and po liti cal structures. In most cases, Orthodox hierarchs were appointed from the families of boyars, thus ensuring a close relationship with the state authorities and its policies. As one of the largest landowners in the principalities, the church had a prime role in administrating healthcare and education. Although the majority of the clergy was uneducated, it dispensed both ecclesiastical and civil justice and in many cases worked closely with boyars in local administration.3 The lower clergy not only contributed directly to the economy but also benefited from tax privileges. Some small villages had an unusually high proportion of clergy in comparison to the overall population. For example, in 1810, Stənisləveşti, a village in the south of Wallachia, was composed of eleven houses and had two priests, five deacons, and three cantors; similarly, the Frəsinet village of nineteen houses had two priests and five deacons.4 Although these cases were exceptional, they indicate both the economic value of being a member of the clergy and the wider canonical dimension of church jurisdiction. The special status of the clergy was reflected not only at lower but also at higher levels. Bishops and metropolitans engaged with state policy and in many cases opposition to the authorities led to the loss of a spiritual seat. The metropolitan of each principality worked with the prince and was president of the divan, the gathering of all boyars. He held the right to be the first person to comment on state policy and to make recommendations when the prince was absent. The metropolitan replaced the prince when the principality had no political ruler, such as in the cases of Metropolitan Veniamin Costachi of Moldavia in 1806 and Metropolitan Dositei Filitti of Wallachia, while the bishops of Buzəu and Argeş were members of the provisional government during the Rus sian occupation of the principalities in 1808. The higher clergy had both religious and political prerogatives in relation to foreign powers as evident in their heading of the boyars' delegation to peace negotiation between the Rus sian and Ottoman empires at Focşani in 1772 and addressing memoranda to the Austrian and Rus sian governments in 1802.5 The primary role of the church in the principalities of Moldavia and Wallachia was paralleled by the national mobilization of Orthodox communities in the neighboring territories that had Romanian inhabitants. Although throughout the region Orthodox communities were incorporated into church structures as part of the Habsburg, Austrian or Rus sian empires, the nineteenth century was characterized by the leadership's search for political autonomy and the building of a Romanian national identity. The Orthodox communities outside the Old Kingdom maintained relations with the faithful in principalities across the Carpathian Mountains and the Dniester River and sought support in their struggle for political and religious rights.

Savages into citizens: Families, political purge, and reconciliation in Cordoba, Argentina, 1820--1862

This dissertation explores the political exclusion and reintegration of families and individuals in Córdoba, Argentina during the early nineteenth-century. Part one is an examination of how Federals in Córdoba managed the process of political identification and purge. Federals set up ad hoc institutions that were responsible for targeting political subversives within provincial communities. From 1831 to 1852, Federals managed to target, or “classify,” over 400 individuals and families in various towns and villages as “savage Unitarians,” a political label that meant the certain loss of rights, property, exile, and worse. Federals also sought active participation among “citizens” from all levels of society. Thus, I argue that the process of correctly identifying a “savage Unitarian” in Córdoba was constantly subject to modification at the local level. I also reconstruct the stories of accused families as they struggled to survive the political purges. Many of the families were large landowners and wealthy merchants, confirming that early republican Argentine political struggles were often intra-elite affairs. However, the “classified” individuals and families also represented a variety of socio-economic, ethnic, and racial groups. ^ The second part of this study focuses on families who petitioned Federal authorities for the restitution of rights and property. They proclaimed their loyalty to the “Federal cause,” and often, they had friends and family who could vouch for their claims. These petitions forced Federal authorities to doubt the precision of political identification and re-think how the ideology of Federalism was defined. Authorities granted most requests for repatriation, thereby creating a process of reintegration that included amnesty and restitution. Yet, this system failed to repair the psychological, emotional, materials, and political effects of political purge. Conflicts between society and state led to numerous misunderstandings about what restitution, justice, and reconciliation meant. The new regime's leaders more often denied restitution claims to formerly accused families and individuals, demonstrating that the journey from “savage” to citizen left an indelible imprint on family life in mid-nineteenth century Argentina. ^

Hyphenated cultures: Ethnicity and nation in Trinidad

This dissertation attempts to unravel why and how postcolonial Trinidad has displayed relative stability in spite of the presence of the factors that have produced conflict and instability in other postcolonial societies.^ Trinidad's distinctive social formation began in the colonial period with a unique politics of culture among the landowning European groups, Anglican English and French Creole. Contrary to the materialist assumption of landowners' class solidarity, the development of Trinidad's plantation economy into two crops, each controlled by a separate European ethno-religious faction, impeded the integration and subsequent ideological domination of European-Christians. Throughout the nineteenth century neither group dominated the other, nor did they fuse into a single ruling class. The dynamics between them both generated recurring conflict while simultaneously creating mechanisms that limited conflict. ^ Based on original in-depth fieldwork and historical analysis, the dissertation proceeds to demonstrate that Trinidad's unique intra-class conflict within the dominant European population has produced hyphenated, as opposed to hybridized cultural elements. Supplementing the historical analysis with empirical examinations of contemporary inter-religious rituals and post-colonial politics this dissertation argues that social integration is inseparable from the question of inter-cultural mixture or articulation. In Trinidad, however, the resulting combination of distinct cultural elements is neither a "plural society" (M.G. Smith 1965; Despres 1967) nor an integrated totality in the structural-functionalistic sense (R.T. Smith 1962; Braithwaite 1967). Moreover, Trinidad does not conform to the post-structural framework's depiction of the social linkage between power and culture. The concept of cultural hybridization is equally misleading in the case of Trinidad. The underlying assumption of a monolithic European population's cultural hegemony and post-structural analysis's almost exclusive focus on the inter -class politics of culture seriously misrepresent and misunderstand Trinidadian cultural and its associated social and political relations. The dissertation examines this reflexive influence of culture not as an instrument of the powerful few but as an autonomous force that reproduces social divisions, yet restrains conflict.^

Essays in economic growth, political economy and institutions

This dissertation analyzes the effects of political and economic institutions on economic development and growth.^ The first essay develops an overlapping-generations political economy model to analyze the incentives of various social groups to finance human capital accumulation through public education expenditures. The contribution of this study to the literature is that it helps explain the observed differences in the economic growth performance of natural resource-abundant countries. The results suggest that the preferred tax rates of the manufacturers on one hand and the political coalition of manufacturers and landowners, on the other hand, are equal to the socially optimal tax rate. However, we show that owners of natural resources prefer an excessively high tax rate, which suppresses aggregate output to a suboptimal level.^ The second essay examines the relationship between the political influence of different social classes and public education spending in panel data estimation. The novel contribution of this paper to the literature is that I proxy the political power and influence of the natural resource owners, manufacturers, and landowners with macroeconomic indicators. The motivation behind this modeling choice is to substantiate the definition of the political power of social classes with economic fundamentals. I use different governance indicators in the estimations to find out how different institutions mediate the overall impact of the political influence of various social classes on public education spending. The results suggest that political stability and absence of violence and rule of law are the important governance indicators.^ The third essay develops a counter argument to Acemoglu et al. (2010) where the thesis is that French institutions and economic reforms fostered economic progress in those German regions invaded by the Napoleonic armies. By providing historical data on urbanization rates used as proxies for economic growth, I demonstrate that similar different rates of economic growth were observed in the regions of France in the post-Napoleonic period as well. The existence of different economic growth rates makes it hard to argue that the differences in economic performance in the German regions that were invaded by the French and those that were spared a similar fate follow from regional differences in economic institutions.^

Annotated record of the detailed examination of Mn deposits from the QUEBRADA (1969) and SIQUEIROS (1974) expeditions around the East Pacific Rise

Basalt samples obtained from the Siqueiros transform fault/fracture zone and the adjacent East Pacific Rise are mostly very fresh oceanic tholeiite and fractionated oceanic tholeiite with Fe+3/ Fe+2 ? 0.25; however, alkali basalts occur in the area as well. The rocks of the tholeiitic suite are ol + pl phyric and ol + pl + cpx phyric basalts, while the alkali basalts are ol and ol + pl phyric. Microprobe analyses of the tholeiitic suite phenocrysts indicate that they are Fo68-Fo86, An58-An75, and augite (Ca34Mg50Fe16). The range of olivine and plagioclase compositions represents the chemical variation of the phenocryst compositions with fractionation. The phenocyrsts in the alkali basalts are Fo81 and An69. The suite of tholeiites comprises a fractionation series characterized by relative enrichment of Fe, Ti, Mn, V, Na, K, and P and depletion of Ca, Al, Mg, Ni, and Cr. The fractionated tholeiites occur on the median ridge (which is a sliver of normal oceanic crust) of the double Siqueiros transform fault, on the western Siqueiros fracture zone, and on the adjoining East Pacific Rise, while the two transform fault troughs contain mostly unfractionated or only slightly fractionated tholeiite. We suggest that the fractionated tholeiites are produced by fractional crystallization of more 'primitive' tholeiitic liquid in a crustal magma chamber below the crest of the East Pacific Rise. This magma chamber may be disrupted by the transform fault troughs, thus explaining the paucity of fractionated tholeiites in the troughs. The alkali basalts are found only on the flanks of a topographic high near the intersection of the northern transform trough with the East Pacific Rise.