Cosmological quintessence accretion onto primordial black holes : conditions for their growth to the supermassive scale

In this work we revisit the growth of small primordial black holes (PBHs) immersed in a quintessential field and/or radiation to the supermassive black hole (SMBHs) scale. We show the difficulties of scenarios in which such huge growth is possible. For that purpose we evaluated analytical solutions of the differential equations (describing mass evolution) and point out the strong fine tuning for that conclusions. The timescale for growth in a model with a constant quintessence flux is calculated and we show that it is much bigger than the Hubble time.The fractional gain of the mass is further evaluated in other forms, including quintessence and/or radiation. We calculate the cosmological density $\Omega$ due to quintessence necessary to grow BHs to the supermassive range and show it to be much bigger than one. We also describe the set of complete equations analyzing the evolution of the BH+quintessence universe, showing some interesting effects such the quenching of the BH mass growth due to the evolution of the background energy. Additional constraints obtained by using the Holographic Bound are also described. The general equilibrium conditions for evaporating/accreting black holes evolving in a quintessence/radiation universe are discussed in the Appendix.Comment: 21 pp., 2 Figures, To appear in IJMP

Reavaliaçao da evoluçao tectono-magmática do Graben de Jaibaras (nordeste do Brasil)

O Graben de Jaibaras é a mais importante bacia de idade cambro-ordoviciana que ocorre em terrenos pré-cambrianos da Província Borborema e do Escudo Nigeriano. Trata-se de uma feição bastante alongada NE-SW, resultado de reativações de descontinuidades miloníticas crustais pertencentes ao Lineamento Transbrasiliano. O preenchimento da bacia, de natureza muito imatura, é geralmente caracterizado por leques aluviais de escarpas de falhas seguidos ve rtical e lateralmente por arenitos fluvio-lacustres interdigitados com extensos pacotes de folhelhos ave rmelhados. A evolução, dominada por uma forte atividade magmática, é outro aspecto fundamental desse graben. Com efeito, o Graben de Jaibaras é um excelente exemplo de uma bacia cujos preenchimento sedimentar e os eventos magmáticos são resultados de processos cogenéticos. A evolução magmática do Graben de Jaibaras compreende basicamente quatro eventos, todos separados temporal e espacialmente. O Enxame de Diques de Coreaú, de idade vendiana, constitui o estágio inicial de abertura do rifte. Antecedendo ao prenchimento do Graben, a evolução desse sistema distensional, no cambriano inferior, permitiu o alojamento do Pluton de Mucambo através de reativação oblíqua da anisotropia crustal delimitadora da borda oeste do Graben. No cambriano médio a sedimentação da bacia foi acompanhada por um volume considerável de magma essencialmente básico (a Suíte Parapuí). Em seguida, houve a intrusão passiva do Pluton de Meruoca. As interações estratigr á ficas entre os eventos magmáticos e as sucessões sedimentares no Graben podem ser perfeitamente estabelecidas a partir das relações estruturais clássicas de “corte e preenchimento” associadas ao bom controle geocronológico. A través da configuração geométrica e da interrelação dos corpos ígneos com as rochas hospedeiras obteve-se o campo de esforços durante a formação e o desenvolvimento do Graben. A partir das características físico-químicas do magmatismo, discutiu-se a resposta térmica da crosta durante a formação e alojamento dos corpos. Nesse contexto, interpreta-se que o Graben foi nucleado durante um campo de stress de direção NW-SE. Esse campo regional, aliado a uma pequena componente direcional ao longo da anisotropias crustais reativadas, persistiu durante todo o desenvolvimento do Graben, incluindo o alojamento dos plutons. Dois modelos termo-mecânicos plausíveis, em termos de geração de calor resultando em magmatismo, foram sugeridos como “motores” regionais na criação do Graben. O modelo 1 envo l ve o desacoplamento da raiz da litosfera previamente espessada, seguido de um desajuste termo-isostático provocado pelo afinamento litosférico, enquanto que material astenosférico quente preencheria o espaço anteriormente ocupado pela parte delaminada da litosfera. O segundo modelo consiste do underplating de magma básico na base da crosta. A vinculação entre esses dois modelos foi considerada como um processo progressivo.The Jaibaras Trough (GJ), located in the Northeast Brazil, represents the most important, prominent and extensive exposure of Early Phanerozoic sedimentary sequences in a wide Brasiliano-age area, including Borborema Province and West Africa (mainly Nigerian Shield). The main basin feature is delineated by major brittle normal faults, resulted from reactivation of mylonite shear zones inside the so-called Transbrasiliano Lineament. The Jaibaras rift evolution is not only partially constrained by the stratigraphic record of the basin in fill, which is characterized by basal fault-scarp-related paraconglomerates followed laterally and vertically by fluvial-lacustrine sandstones which are interbeded with reddish shale, but also by the petrological signatura rift-related magmatic activity. Magmatic evolutive aspects of GJ comprises basically four temporal and spatially separated igneous steps. The earlier phase involved the Coreaú dike swa rm, which is Vendian in age, representing the initial tectonic pulse of the rift opening. With the continued breakup, reactivation of deeper shear zones gave rise to the emplacement of Mucambo Pluton during Early Cambrian times, preceding the main rift infill. The basin sedimentation was accomppanied by huge volume of volcanism, most of it occurring as flood basalts, dikes and sills in shape. The Meruoca Pluton is the last basin-related igneous manifestation during Upper Cambrian. Sequential stratigraphic interactions between sediments and magmatic events are perfectly constrained at the expense of thermal-structural features such as contact aureoles, faulted contacts, abuting and cross-cuting. Local and regional stress-field during GJ formation were obtained by using the configuration of magmatic bodies and their interplays with host-rocks. The physical-chemical characteristics of igneous activity also allows us to discuss the simultaneous thermal crustal-mantelic response due to magmagenesis and the emplacement processes. Initially, during the GJ nucleation, a NW-SE extensional pulse is recorded by the intrusion of the Coreaú Dike Swa rm, following hydraulic fracturing model. Following the same extensional stress-field, the studied plutons were emplaced by using nort h west-trending preexisting basement structures in areas of releasing bends where their feeder dikes were intruded. We hypothesize that two distinctive thermo-mechanical models are able to produce substantial heat flow (magma as consequence) within the JT and surrounding rift-host lineament. The model 1 invo l ves the peeling of the lower part of continental lithosphere from crust, followed by lithospheric thinning while hot upwelling asthenospheric replace the original cold lithospheric material. Decompression in the ascending mantle leads to partial melting and bimodal magmatism (crust and mantle) take place; the second model consists of underplating of mafic material probably in a stretched crust-mantle boundary. The changing from the model 1 to model 2 seems to be a progressive process

Holographic Principle bounds on Primordial Black Hole abundances

The generalized Second Law of thermodynamics and the Holographic Principle are combined to obtain the maximum mass of black holes formed inside a static spherical box of size $R$ filled with radiation at initial temperature $T_{i}$. The final temperature after the formation of black holes is evaluated, and we show that a critical threshold exists for the radiation to be fully consumed by the process. We next argue that if some form of Holographic Principle holds, upper bounds to the mass density of PBHs formed in the early universe may be obtained. The limits are worked out for inflationary and non-inflationary cosmological models. This method is independent of the known limits based on the background fluxes (from cosmic rays, radiation and other forms of energy) and applies to potentially important epochs of PBH formation, resulting in quite strong constraints to $\Omega_{pbh}$.Comment: Latex file, 2 .ps figures. To appear in Classical and Quantum Gravit

Correlação entre distância genética e heterose para comprimento de panícula por cruzamento dialélico entre acessos de arroz (Oryza sativa L.) de base genética ampla.

O objetivo desse trabalho foi correlacionar os dados de distância genética de Rogers modificada por Wright e a heterose observada no caractere comprimento de panícula, um dos componentes de produtividade do arroz, dos 120 híbridos obtidos nesses cruzamentos

Obtention of plant peroxidase and its potential for the decolorization of the reactive dye Remazol Turquoise G 133%

Peroxidases can be used in the decolorization process. There is a growing interest for new sources of this enzyme and for obtaining economically viable processes. In this work, a low-cost vegetable peroxidase extraction process is proposed; the resulting enzyme is characterized to determine its optimum pH, temperature, and stability conditions, and it is then applied in the decolorization of reactive dye Remazol Turquoise G 133%. The turnip peroxidase (TP) was utilized as an enzymatic source. This enzyme exhibited maximum activity at pH 7.0, and it was active in the temperature range of 30 to 50 °C, which favors its use in industrial processes. Acetone was the most efficient solvent to induce precipitation. The removal of Remazol Turquoise G 133% was 56.0% complete after 50 min, while 41.0% of the same dye was removed with the commercial horseradish peroxidase enzyme in 50 min. TP presents potential as a viable alternative in the decolorization of textile wastewaters

Growth performance, in vitro antioxidant properties and chemical composition of the halophyte Limonium algarvense Erben are strongly influenced by the irrigation salinity

Limonium algarvense Erben (sea lavender) is a halophyte species with potential to provide natural ingredients with in vitro antioxidant, anti-inflammatory, neuroprotective and antidiabetic properties. This study reports for the first time the 1) cultivation of sea lavender in greenhouse conditions under irrigation with freshwater (approx. 0 mM NaCl) and saline aquaculture wastewater (300 and 600 mM NaCl), and 2) the influence of the irrigation salinity on the plant performance (e.g growth, number of produced leaves and flowers), in vitro antioxidant properties [radical scavenging activity (DPPH and ABTS), ferric reducing antioxidant power (FRAP), metal chelating properties on copper (CCA) and iron (ICA)], toxicity (in vitro on three mammalian cell lines) and chemical composition (determined by LC-ESI-HRMS/MS). The freshwater-irrigated plants had better growth performance than those irrigated with saltwater. Extracts from wild plants, had the highest antioxidant activity, but those from cultivated ones kept high in vitro antioxidant properties and interesting chemical profile. The flowers' extracts of plants irrigated with 300 mM NaCl had the highest antioxidant activities against DPPH, whereas those from freshwater-irrigated plants were more active on ABTS, CCA and FRAP. Most of the extracts showed nil toxicity. The flowers' extracts displayed the highest diversity of compounds, mainly quercetin, apigenin, luteolin, naringenin and their glycoside derivatives. Moreover, their abundance varied with the irrigation salinity. These data indicate that sea lavender plants can be successfully cultivated in greenhouse conditions under fresh- and saltwater irrigation, maintaining interesting biological and chemical properties.Funding Agency Portuguese Foundation for Science and Technology Portuguese National Budget CCMAR/Multi/04326/2019 GreenVet project ALG-01-0145-FEDER-028876 XtrerneAquaCrops FA-05-2017-028 Lisboa-01-0145-FEDER-022125-RNEM-IST ID/QUI/00100/201 Portuguese Foundation for Science and Technology SFRH/BD/116604/2016 CEECIND/00425/2017info:eu-repo/semantics/publishedVersio

Custo de produção de mudas clonais de Café Arábica produzidas por embriogênese somática

A produção de mudas clonais de café pode ser feita de diferentes formas. Entretanto, a produção por embriogênese somática é a que tem despontado como a mais promissora. A embriogênese somática permite a produção de mudas em larga escala a partir de folhas usadas como explantes. Plantas obtidas por esse processo apresentam comportamento semelhante ao de plantas oriundas de sementes, não havendo limitação para a sua utilização comercial. A produção de mudas clonais de café é realizada em laboratórios de cultura de tecidos adaptados para a produção em escala industrial, denominados de biofábricas. Todavia, a produção de mudas clonais via embriogênese somática é uma técnica que ainda não foi explorada comercialmente no Brasil e não existe uma estimativa do custo de produção de mudas clonais de café arábica. Assim, o objetivo no presente trabalho foi calcular o custo de produção de mudas clonais de café em uma biofábrica de pequeno porte, tendo-se como base o protocolo desenvolvido pela Fundação Procafé/Embrapa Café, com a colaboração de pesquisadores da Embrapa Recursos Genéticos e Biotecnologia e do Centro de Cooperação Internacional em Pesquisa Agronômica para o Desenvolvimento, CIRAD, França. Este trabalho apresenta também uma relação dos equipamentos e materiais necessários para a produção de mudas de café in vitro. O custo de produção de uma muda foi de R$0,97 para uma produção anual de 400.000 mudas, utilizando-se o plantio de embriões pré-germinados diretamente em tubetes. Caso a etapa de produção de plântulas em potes in vitro seja utilizada, o custo de produção passa a ser de R$1,34

Reavaliaçao da evoluçao tectono-magmática do Graben de Jaibaras (nordeste do Brasil)

The Jaibaras Trough (GJ), located in the Northeast Brazil, represents the most important, prominent and extensive exposure of Early Phanerozoic sedimentary sequences in a wide Brasiliano-age area, including Borborema Province and West Africa (mainly Nigerian Shield). The main basin feature is delineated by major brittle normal faults, resulted from reactivation of mylonite shear zones inside the so-called Transbrasiliano Lineament. The Jaibaras rift evolution is not only partially constrained by the stratigraphic record of the basin in fill, which is characterized by basal fault-scarp-related paraconglomerates followed laterally and vertically by fluvial-lacustrine sandstones which are interbeded with reddish shale, but also by the petrological signatura rift-related magmatic activity. Magmatic evolutive aspects of GJ comprises basically four temporal and spatially separated igneous steps. The earlier phase involved the Coreaú dike swa rm, which is Vendian in age, representing the initial tectonic pulse of the rift opening. With the continued breakup, reactivation of deeper shear zones gave rise to the emplacement of Mucambo Pluton during Early Cambrian times, preceding the main rift infill. The basin sedimentation was accomppanied by huge volume of volcanism, most of it occurring as flood basalts, dikes and sills in shape. The Meruoca Pluton is the last basin-related igneous manifestation during Upper Cambrian. Sequential stratigraphic interactions between sediments and magmatic events are perfectly constrained at the expense of thermal-structural features such as contact aureoles, faulted contacts, abuting and cross-cuting. Local and regional stress-field during GJ formation were obtained by using the configuration of magmatic bodies and their interplays with host-rocks. The physical-chemical characteristics of igneous activity also allows us to discuss the simultaneous thermal crustal-mantelic response due to magmagenesis and the emplacement processes. Initially, during the GJ nucleation, a NW-SE extensional pulse is recorded by the intrusion of the Coreaú Dike Swa rm, following hydraulic fracturing model. Following the same extensional stress-field, the studied plutons were emplaced by using nort h west-trending preexisting basement structures in areas of releasing bends where their feeder dikes were intruded. We hypothesize that two distinctive thermo-mechanical models are able to produce substantial heat flow (magma as consequence) within the JT and surrounding rift-host lineament. The model 1 invo l ves the peeling of the lower part of continental lithosphere from crust, followed by lithospheric thinning while hot upwelling asthenospheric replace the original cold lithospheric material. Decompression in the ascending mantle leads to partial melting and bimodal magmatism (crust and mantle) take place; the second model consists of underplating of mafic material probably in a stretched crust-mantle boundary. The changing from the model 1 to model 2 seems to be a progressive process