A General Rate Duality of the MIMO Multiple Access Channel and the MIMO Broadcast Channel

We present a general rate duality between the multiple access channel (MAC) and the broadcast channel (BC) which is applicable to systems with and without nonlinear interference cancellation. Different to the state-of-the-art rate duality with interference subtraction from Vishwanath et al., the proposed duality is filter-based instead of covariance-based and exploits the arising unitary degree of freedom to decorrelate every point-to-point link. Therefore, it allows for noncooperative stream-wise decoding which reduces complexity and latency. Moreover, the conversion from one domain to the other does not exhibit any dependencies during its computation making it accessible to a parallel implementation instead of a serial one. We additionally derive a rate duality for systems with multi-antenna terminals when linear filtering without interference (pre-)subtraction is applied and the different streams of a single user are not treated as self-interference. Both dualities are based on a framework already applied to a mean-square-error duality between the MAC and the BC. Thanks to this novel rate duality, any rate-based optimization with linear filtering in the BC can now be handled in the dual MAC where the arising expressions lead to more efficient algorithmic solutions than in the BC due to the alignment of the channel and precoder indices.Comment: Submitted to IEEE Globecom 2008; Fixed dimensions of channel matrix H_k and covariance matrix Z_k, slightly modified conclusio

The Grota Funda iron oxide copper-gold (IOCG) deposit, Carajás Domain (PA) : hydrothermal alteration, fluid evolution and mineralization age

Orientadores: Roberto Perez Xavier, Carolina Penteado Natividade MoretoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de GeociênciasResumo: O depósito de óxido de ferro cobre-ouro (IOCG) Grota Funda está localizado na porção noroeste do Domínio Carajás, um segmento Arqueano (3,0 - 2,55 Ga) da Província Carajás, no sudeste do Cráton Amazônico. Situado em uma zona de cisalhamento regional de direção WNW-ESE (Sistema Transcorrente Pojuca), onde também se encontram os depósitos de Cu-Au Gameleira e Cu-Zn Pojuca, o depósito insere-se em sequências vulcano-sedimentares do Grupo Igarapé-Pojuca, compreendendo basalto, diabásio, gabro e dacito subordinado, além de formações ferríferas bandadas. Nesta sequência, as rochas metavulcânicas máficas correspondem às principais hospedeiras das mineralizações cupro-auríferas. A evolução paragenética do sistema hidrotermal do depósito Grota Funda engloba uma alteração hidrotermal cálcica-sódica de alta temperatura (albita-hastingsita-escapolita), seguida por intenso metassomatismo rico em Fe (magnetita-grunerita-almandina), alteração potássica com biotita, precipitação de clorita-quartzo-turmalina e veios de carbonato-quartzo tardios. Episódios de mineralizações de cobre (-ouro) associam-se espacialmente às zonas enriquecidas em ferro, de alteração potássica e cloritizas. A idade de 2530 ± 60 Ma, obtida através da datação Re-Os em molidenita associado a veios de grunerita-magnetita, é interpretada como a idade de formação do primeiro estágio de mineralização no depósito. A principal zona de minério está espacialmente associada às zonas de alteração potássica com brechas constituídas por calcopirita-magnetita-esfalerita-pirrotita-pentlandita. A paragênese do minério sugere condições de baixa ¿S2 e ¿O2 para os fluidos mineralizantes. O desenvolvimento da assembléia de alteração cálcica-sódica é atribuído à circulação regional de fluidos hipersalinos e metalíferos de alta temperatura (> 500°C). A mistura desses fluidos hipersalinos com fluidos mais frios e de salinidade moderada à elevada (24 a 29 wt% NaCl + CaCl2 equiv.), resultando em uma diminuição da temperatura e da atividade de Cl- do sistema, é interpretado como o principal processo desencadeador da precipitação de metais na zona de minério principal. As associações de alteração pós-mineralização (clorita-quartzo-turmalina e carbonato-quartzo) refletem decréscimos graduais de temperatura, salinidade e pH dos fluidos. Além disso, as composições isotópicas de boro (ð11B = +8,2¿ a + 13,6¿) em turmalina associada às zonas de alteração clorítica são atribuídas a fontes mistas, incluindo boro proveniente de salmouras marinhas (e.g. água do mar evoluída ou fluidos do tipo bittern) e boro lixiviado das rochas hospedeiras (e.g. metavulcânicas máficas)Abstract: The Grota Funda iron oxide copper-gold deposit (IOCG) is located at the northwestern portion of the Carajás Domain, an Archean (3.0 - 2.55 Ga) segment of the Carajás Province, in the southeastern sector of the Amazonian Cráton. Within the same regional WNW-ESE-striking shear zone (Pojuca Fault System) in which lie the Gameleira (Cu-Au) and Pojuca (Cu-Zn) deposits, volcano-sedimentary sequences of the Igarapé-Pojuca Group, comprising basalt, diabase, gabbro and dacitic rocks and banded iron formations, are the main lithotypes recognized in the deposit area. In this sequence, mafic metavolcanic rocks represent the main hosts to the copper(-gold) mineralizations. The paragenetic evolution of the Grota Funda hydrothermal system encompasses an early high-temperature calcic-sodic hydrothermal alteration (albite-hastingsite-scapolite), ensued by intense Fe-metasomatism (magnetite-grunerite-almandine), potassic alteration with biotite, chlorite-quartz-tourmaline precipitation, and late carbonate-quartz veining. Copper (-gold) mineralizations are spatially and temporally associated with iron-enriched, potassically-altered and chlorite-altered zones. Molybdenite from grunerite-magnetite veins yielded a Re-Os model age of 2,530 ± 60 Ma, which is interpreted as a mineralization age coeval with the Fe-metasomatism. The main sulfide ore is spatially associated with potassically-altered zones, and predominantly forms breccia bodies characterized by a chalcopyrite-magnetite-sphalerite-pyrrhotite-pentlandite assemblage. The ore paragenesis suggests a mineralizing fluid at low ¿S2 e ¿O2 conditions. Development of early and high temperature (> 500°C) alteration assemblages (albite, scapolite-hastingsite) is attributed to regional circulation of deep-seated hypersaline and metalliferous fluids. Mixing with moderate to high salinity (24 to 29 wt% NaCl + CaCl2 equiv.) and cooler fluids, may have triggered ore precipitation in the main ore zone, due to a decrease in temperature and Cl¿ activity. Post-ore alteration assemblages (chlorite-quartz-tourmaline, carbonate-quartz) resulted from considerable temperature, salinity and pH decrease. In addition, boron isotopic compositions (ð11B = +8,2¿¿a + 13,6¿) of tourmaline from the chlorite alteration zone are attributed to mixed sources, including isotopically heavier boron sourced fluids, possibly represented by highly saline brines (e.g., evolved seawater, formation water or bittern fluids) and light boron leached from the host rocks (e.g mafic metavolcanic rocks)MestradoGeologia e Recursos NaturaisMestre em GeociênciasCAPE

The Santa Lúcia Cu-Au deposit, Carajás Mineral Province, Brazil: a Neoarchean (2.68 Ga) member of the granite-related copper-gold systems of Carajás

The Santa Lúcia copper-gold deposit lies in the southeastern portion of the Carajás Mineral Province, along NW-SE splays of the Carajás Fault. The deposit is hosted by a rhyolitic subvolcanic rock, which is crosscut by pegmatite intrusions. The paragenetic evolution at Santa Lúcia encompasses an early stage of chlorite alteration, followed by potassic alteration with microcline, greisenization (quartz-muscovite-tourmaline), copper-gold ore precipitation, and late sericite and hematite vein formation/ fracture infill. Copper mineralization is dominantly represented by chalcopyrite-sphalerite-pyrrhotite-pentlandite-pyrite breccias, which are spatially associated with greisen alteration and characterized by the enrichment of light rare earth elements (LREE), Ni, Co, and Cr. The alteration types, mineralization styles, and ore assemblage suggest that the Santa Lúcia deposit could represent a member of the Paleoproterozoic (ca. 1.88 Ga) granite-related copper-gold systems of Carajás (e.g., the Breves and Estrela deposits). However, the in situ U-Pb analyses of ore-related monazite yield a weighted average 207Pb/206Pb age of 2688 ± 27 Ma, thereby constraining the timing of mineralization at Santa Lúcia to the Neoarchean. Moreover, tourmaline from the pegmatite and within the ore zones has a range of δ11B values from − 3.7 to − 0.6‰, therefore linked to a magmatic boron source. Collectively, these results indicate that the Santa Lúcia deposit is the first reduced magmatic-hydrothermal, iron oxide–poor system formed in the Neoarchean, coeval with the 2.72–2.68 Ga metallogenic event responsible for the genesis of important iron oxide copper-gold (IOCG) deposits in the Carajás Mineral Province

A mesoionic carbene complex of manganese in five oxidation states

Reaction between a carbazole-based mesoionic carbene ligand and manganese(II) iodide results in the formation of a rare air-stable manganese(IV) complex after aerobic workup. Cyclic voltammetry reveals the complex to be stable in five oxidation states. The electronic structure of all five oxidation states is elucidated chemically, spectroscopically (NMR, high-frequency EPR, UV-Vis, MCD), magnetically, and computationally (DFT, CASSCF)

A mesoionic carbene complex of manganese in five oxidation states

Reaction between a carbazole-based mesoionic carbene ligand and manganese(ii) iodide results in the formation of a rare air-stable manganese(iv) complex after aerobic workup. Cyclic voltammetry reveals the complex to be stable in five oxidation states. The electronic structure of all five oxidation states is elucidated chemically, spectroscopically (NMR, high-frequency EPR, UV-Vis, MCD), magnetically, and computationally (DFT, CASSCF).Fil: Wittwer, Benjamin. Universidad de Innsbruck; AustriaFil: Dickmann, Nicole. University of Paderborn; AlemaniaFil: Berg, Stephan. University of Paderborn; AlemaniaFil: Leitner, Daniel. Universidad de Innsbruck; AustriaFil: Tesi, Lorenzo. Universitat Stuttgart; AlemaniaFil: Hunger, David. Universitat Stuttgart; AlemaniaFil: Gratzl, Raphael. Universidad de Innsbruck; AustriaFil: van Slageren, Joris. Universitat Stuttgart; AlemaniaFil: Neuman, Nicolás Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina. Universitat Stuttgart; AlemaniaFil: Munz, Dominik. Universitat Saarland; Alemania. Universitat Erlangen Nuremberg; AlemaniaFil: Hohloch, Stephan. Universidad de Innsbruck; Austri