Thievery in rainforest fungus-growing ants: interspecific assault on culturing material at nest entrance

COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCleptobiosis in social insects refers to a relationship in which members of a species rob food resources, or other valuable items, from members of the same or a different species. Here, we report and document in field videos the first case of cleptobiosis653507510COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQsem informação2014/23141-1, 2017/16645-1306115/2013-1, 302219/2017-0We thank Edward O. Wilson, Bert Hölldobler, Rainer Wirth and Rodrigo Feitosa for feedback on the manuscript, and Luisa Mota for the drawing. MR and GM were funded by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; PO was supported by th

Inducing the cosmological constant from five-dimensional Weyl space

We investigate the possibility of inducing the cosmological constant from extra dimensions by embedding our four-dimensional Riemannian space-time into a five-dimensional Weyl integrable space. Following approach of the induced matter theory we show that when we go down from five to four dimensions, the Weyl field may contribute both to the induced energy-tensor as well as to the cosmological constant, or more generally, it may generate a time-dependent cosmological parameter. As an application, we construct a simple cosmological model which has some interesting properties.Comment: 7 page

Mineralogy and chemistry of incrustations resulting from the 2014-15 eruption of Fogo volcano, Cape Verde

The last eruption of the Fogo volcano, in the Cape Verde Archipelago, occurred in 2014-2015. A mineralogical and chemical study was undertaken on fumarole incrustations resulting from this event and compared with results obtained from the previous 1995 eruption. The mineralogical constitution of the fumarole deposits was assessed by X-ray diffraction and the chemical characterization was performed through X-ray fluorescence spectrometry with a wavelength dispersive system and by energy dispersive X-ray fluorescence at the European Synchrotron Radiation Facility. The most common compounds/minerals in solid deposits were sulfur, sodium chloride, and calcium sulphates with variable degrees of hydration, sodium sulphate, hydrated sulphates of sodium aluminum, potassium magnesium, or sodium magnesium and a fluorine-bearing mineral. Thenardite (Na2SO4) and its polymorph (phase III) were found simultaneously for the first time in incrustations, to the best of our knowledge. A large span of minor and trace elements present in incrustations (Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Ba, Ce, Tl, Pb) were also identified, some of them potentially hazardous to animal and human health. This study reveals that low temperature incrustations, allied to the atmospheric conditions of Fogo volcano, constitute a natural laboratory to observe the process of mineral formation-namely the Na2SO4 phase III considered metastable.This research received financial support from FCT (Fundação para a Ciência e Tecnologia) through project FIRE (PTDC/GEO-GEO/1123/2014). We acknowledge the European Synchrotron Radiation Facility for provision of synchrotron radiation facilities and in particular in using beamline BM 25A. Special thanks are due to the guides Manuel Montrond Fernandes (Izaquiel) and Edimar Montrond that helped us in the Fogo volcano. J.P. Veiga acknowledges funding by FEDER funds through the COMPETE 2020 Programme and National Funds through FCT-Portuguese Foundation for Science and Technology under the project UID/CTM/50025/2013 and the funding from the European Union Horizon 2020 research and innovation programme H2020-DRS-2015 GA nr. 700395 (HERACLES project). Carla Candeias would also like to acknowledge FCT by the grant SFRH/BPD/99636/2014 and UID/GEO/04035/2013. Special thanks are also due to Dr. Tonci Balic-Žunic, an anonymous reviewer and to the editors for their comments on the manuscript. We are also grateful to Dr. Lídia Quental for the satellite image of Fogo Island

Space-time inhomogeneity, anisotropy and gravitational collapse

We investigate the evolution of non-adiabatic collapse of a shear-free spherically symmetric stellar configuration with anisotropic stresses accompanied with radial heat flux. The collapse begins from a curvature singularity with infinite mass and size on an inhomogeneous space-time background. The collapse is found to proceed without formation of an even horizon to singularity when the collapsing configuration radiates all its mass energy. The impact of inhomogeneity on various parameters of the collapsing stellar configuration is examined in some specific space-time backgrounds.Comment: To appear in Gen. Relativ. Gra

A quantum-like description of the planetary systems

The Titius-Bode law for planetary distances is reviewed. A model describing the basic features of this rule in the "quantum-like" language of a wave equation is proposed. Some considerations about the 't Hooft idea on the quantum behaviour of deterministic systems with dissipation are discussed.Comment: LaTex file, 17 pages, no figures. Version published in Foundations of Physics, August 200

Estudo de parâmetros mecânicos de dois solos arenosos estabilizados com cimento

O solo é o material natural de construção mais abundante na natureza e detém muitas vezes propriedades excelentes que o tornam apetecível enquanto material de construção: é resistente, esteticamente agradável, plástico, e tem um baixo custo. Sendo uma das metas primordiais de uma obra a racionalização de custos, a utilização dos solos existentes no local é, desde há muito tempo, um objetivo apetecível. No entanto, nem todos os solos, devido a fatores tais como a granulometria, a composição mineralógica ou a presença de matéria orgânica, se comportam de modo aceitável em termos mecânicos. A adição de cimento Portland modifica as propriedades dos solos através de processos físico-químicos entre os grãos do solo e o cimento, promovendo a formação de um esqueleto que cimenta e envolve os grãos. Neste trabalho estudou-se a melhoria de dois solos através da estabilização com cimento Portland. Os resultados obtidos permitiram concluir que o comportamento mecânico melhorou com o tempo de cura dos provetes e com o aumento do teor de ligante. Foi ainda possível definir uma razão entre a resistência à compressão diametral e a resistência à compressão uniaxial simples. Determinou-se que existe um teor em água “ótimo” que permite obter um comportamento mecânico mais competente. Concluiu-se que existe uma razão água/cimento (w/c) “ótima” para cada teor de ligante, e que esta tende a diminuir com o aumento deste último.Soil is the most abundant natural building material in nature and often has excellent properties that make it attractive to use in construction due to its resistance, pleasant aesthetic appearance, plasticity, and low cost. Since one of the main goals of a project is to rationalize costs, the use of existing soils on site has long been an attractive objective. Nevertheless, not all soils, due to factors such as granulometry, mineralogical composition or the presence of organic matter, behave in an acceptable way in mechanical terms. The addition of Portland cement modifies soil properties through physical-chemical processes between soil grains and cement, promoting the formation of a skeleton that cements and surrounds the grains. In this work, the improvement of two soils through stabilization with Portland cement was studied. The results obtained allowed us to conclude that the mechanical behavior improved with the curing time of the specimens and with the increase in the binder content. It was also possible to define a ratio between the diametral compressive strength and the simple uniaxial compressive strength. It was determined that there is an “optimal” water content that allows to obtain a more competent mechanical behavior. It was concluded that there is an “optimal” water/cement (w/c) ratio for each binder content, and that this ratio tends to decrease with the increase of the latter

Effective degradation of phenacetin in wastewater by (photo)electro-Fenton processes: Investigation of variables, acute toxicity, and intermediates

Electro-Fenton (EF) and solar photoelectro-Fenton (SPEF) processes were employed at different scales to degrade phenacetin (PNT), the first synthetic analgesic. EF experiments were conducted at lab scale, whereas SPEF experiments were performed in an 8 L pre-pilot plant using an electrochemical filter-press cell. Under optimal conditions (25 mg L−1 PNT, 25.3 mg L−1 Fe2+, and current density of 59.5 mA cm−2), EF resulted in degradation and mineralization degrees of 83.9% and 45.2% at 14 and 230 min, respectively. Similarly, PNT was spiked into real wastewater from a municipal secondary treatment plant, resulting in degradation of 68.0% and mineralization of 39.4%, with an energy consumption of 7.0 kWh g−1. The optimal conditions of SPEF (16.8 mg L−1 Fe2+ and current density of 45.9 mA cm−2) led to degradation and mineralization degrees of 55.9% and 37.1% at 36 and 181 min, respectively, with a low energy consumption of 0.142 kWh g−1. Both processes effectively detoxified the solutions, as demonstrated by tests with Artemia salina and Lactuca sativa. Three distinct degradation pathways were proposed based on the identification of eleven reaction intermediates formed upon •OH attack. In conclusion, the low energy cost of the SPEF process underscores its potential for pharmaceutical degradation in wastewater