Experimental determination of the eutectic temperature in air of the CuO-TiO2 pseudobinary system

Eutectic temperature and composition in the CuO–TiO2 pseudobinary system have been experimentally determined in air by means differential thermal analysis (DTA), thermogravimetry (TG) and hot-stage microscopy (HSM). Samples of the new eutectic composition treated at different temperatures have been characterized by X-ray diffraction (XRD) and X-ray absorption near-edge structural spectroscopy (XANES) to identify phases and to determine the Cu valence state, respectively. The results show that the eutectic temperature in air is higher by 100 °C (∼1000 °C) for a Ti-richer composition (XTiO2=25 mol%) than the one calculated in the literature. The reduction of Cu2+ to Cu+ takes places at about 1030 °C. The existence of Cu2TiO3 and Cu3TiO4 has been confirmed by XRD in the temperature range between 1045 and 1200 °C

Ethnobotanical knowledge is vastly under-documented in northwestern South America

A main objective of ethnobotany is to document traditional knowledge about plants before it disappears. However, little is known about the coverage of past ethnobotanical studies and thus about how well the existing literature covers the overall traditional knowledge of different human groups. To bridge this gap, we investigated ethnobotanical data-collecting efforts across four countries (Colombia, Ecuador, Peru, Bolivia), three ecoregions (Amazon, Andes, Chocó), and several human groups (including Amerindians, mestizos, and Afro-Americans). We used palms (Arecaceae) as our model group because of their usefulness and pervasiveness in the ethnobotanical literature. We carried out a large number of field interviews (n = 2201) to determine the coverage and quality of palm ethnobotanical data in the existing ethnobotanical literature (n = 255) published over the past 60 years. In our fieldwork in 68 communities, we collected 87,886 use reports and documented 2262 different palm uses and 140 useful palm species. We demonstrate that traditional knowledge on palm uses is vastly under-documented across ecoregions, countries, and human groups. We suggest that the use of standardized data-collecting protocols in wide-ranging ethnobotanical fieldwork is a promising approach for filling critical information gaps. Our work contributes to the Aichi Biodiversity Targets and emphasizes the need for signatory nations to the Convention on Biological Diversity to respond to these information gaps. Given our findings, we hope to stimulate the formulation of clear plans to systematically document ethnobotanical knowledge in northwestern South America and elsewhere before it vanishesThis study was funded by the European Union, 7th Framework Programme (contract no. 212631), the Russel E. Train Education for Nature Program of the WWF (to NPZ), the Anne S. Chatham fellowship of the Garden Club of America (to NPZ), and the Universidad Autónoma de Madrid travel grants programme (to RCL

Comparative phylogenetic methods and the cultural evolution of medicinal plant use

Human life depends on plant biodiversity and the ways in which plants are used are culturally determined. Whilst anthropologists have used phylogenetic comparative methods (PCMs) to gain an increasingly sophisticated understanding of the evolution of political, religious, social, and material culture, plant use has been almost entirely neglected. Medicinal plants are of special interest because of their role in maintaining people’s health across the world. PCMs in particular, and cultural evolutionary theory in general, provide a framework in which to study the diversity of medicinal plant applications cross-culturally, and to infer changes in plant use through time. These methods can be applied to single medicinal plants as well as the entire set of plants used by a culture for medicine, and they account for the non-independence of data when testing for floristic, cultural or other drivers of plant use. With cultural, biological, and linguistic diversity under threat, gaining a deeper and broader understanding of the variation of medicinal plant use through time and space is pressing

Relevance of Stress and Female Sex Hormones for Emotion and Cognition

There are clear sex differences in incidence and onset of stress-related and other psychiatric disorders in humans. Yet, rodent models for psychiatric disorders are predominantly based on male animals. The strongest argument for not using female rodents is their estrous cycle and the fluctuating sex hormones per phase which multiplies the number of animals to be tested. Here, we will discuss studies focused on sex differences in emotionality and cognitive abilities in experimental conditions with and without stress. First, female sex hormones such as estrogens and progesterone affect emotions and cognition, contributing to sex differences in behavior. Second, females respond differently to stress than males which might be related to the phase of the estrous cycle. For example, female rats and mice express less anxiety than males in a novel environment. Proestrus females are less anxious than females in the other estrous phases. Third, males perform in spatial tasks superior to females. However, while stress impairs spatial memory in males, females improve their spatial abilities, depending on the task and kind of stressor. We conclude that the differences in emotion, cognition and responses to stress between males and females over the different phases of the estrous cycle should be used in animal models for stress-related psychiatric disorders

State of the world’s plants and fungi 2020

Kew’s State of the World’s Plants and Fungi project provides assessments of our current knowledge of the diversity of plants and fungi on Earth, the global threats that they face, and the policies to safeguard them. Produced in conjunction with an international scientific symposium, Kew’s State of the World’s Plants and Fungi sets an important international standard from which we can annually track trends in the global status of plant and fungal diversity

Electron Paramagnetic Resonance study of hopping in CCTO mixed with TiO2

Electron Paramagnetic Resonance (EPR) is used to study the transport properties in CaCu3Ti4O12 (CCTO) and its mixtures with TiO2. The temperature dependence of the peak to peak linewidth of the EPR spectra in the temperature range 430 ≤ T ≤ 660 K, is studied for the powders of CCTO, 5% CCTO + 95% TiO2 and 1% CCTO + 99% TiO2. All the samples show a behavior predicted by the Small Polaron Hopping model. This behavior is studied as a function of the TiO2 content, finding an activation energy that decreases with increasing TiO2 concentration. We found that two mechanisms govern the conductivity in these system one, intrinsic to the CCTO, via oxygen vacancies and the other one, which improve the conductivity, related to the polarizability of the Ti-ions at the surface of the grains and mediated by the oxygen vacancies at the surface of the CCTO.Two of the authors, Leonardo Vivas and Pedro Silva, want to acknowledge to the Venezuelan Institute for Scientific Research for the support in the development of this research.Peer reviewe

Structure, microstructure and electrical properties of Cu2+ doped (K,Na,Li)(Nb,Ta,Sb)O3 piezoelectric ceramics

International audienceThis work studies the effects of copper doping on the properties of the (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3 piezoelectric ceramic material. Cu2þ incorporation into the perovskite structure produces a transformation of the crystalline lattice from tetragonal to orthorhombic symmetry together with an increase of the secondary phase. The grain size of the ceramic samples is increased due to the formation of a liquid phase during sintering, which increases with the Cu2þ content. EDS analysis reveals that the secondary-phase regions present a Cu and Nb-rich composition, indicating that the Cu-excess accommodates through the formation of this secondary phase. Cu-doping induces a rapid increase of the orthorhombic-tetragonal phase transition temperature, while the tetragonal-cubic phase transition temperature is decreased, the latter becoming more diffuse with the increase of Cu content. The piezoelectric properties of the material are reduced with the copper concentration, whereas the mechanical quality factor increases by a factor of nearly four