Search results for "REEs"

Focal waveforms with tunable carrier frequency using dispersive aperturing

2008

We introduce the concept of dispersive aperturing involving a beam truncation by hard-edge apertures where diameter of the processed beam changes upon frequency. Applied to focused waves, this procedure transforms power spectra at the focal point (and the surroundings). Waveforms at focus conserve pulse duration but carrier frequency may be altered substantially. In principle, some degrees of freedom allow carrier-frequency tuning at convenience.

Towards a more sustainable food Supply chain: opening up invisible waste in food service

2016

Future challenges to the global food supply chain are complex. In order to embrace sustainability, companies should change their management practices towards more efficient resource use. Food waste being a misuse of resources, we identify its causes and possible ways of minimising it. To achieve this goal, we conducted explorative research with qualitative and quantitative data through in-depth semi-structured interviews and an open questionnaire with top Spanish food service companies. Results show that most businesses mainly tend to minimise food waste according to economic criteria, without taking into account the social, ethical or environmental factors. As a consequence, just “visible”…

Analysis of geochemical tracers in different systems soil-Citrus limon (L.) Osbeck

Today is increasing the attention of consumers for the origin of food and high reputation of products with a distinct geographical identity. Food traceability is an important issue in food safety and quality control, with impacts on food security, its quantity and overall availability. The knowledge of a chemistry relationship between the soil and the agricultural products is an important tool for the quality assessment of food. Citrus Limon is the most important fruit tree crop in the world and the detection of potential fraud could improve by using tools linking the chemistry composition of this production to its typical growing area. This study use rare earth elements (REEs) as geochemic…

Análisis de contenido de la representación del cuerpo en un libro de texto de Educación Preescolar

2012

La construccion social y cultural del cuerpo influye en el conocimiento personal y de los otros. Los libros de texto transmiten el capital cultural de una sociedad a sus ciudadanos mas pequenos. El objetivo del estudio consiste en describir la forma en que se representa el cuerpo en las imagenes de un libro de texto de educacion preescolar. Se realizo un analisis de contenido de las imagenes a traves de un codigo elaborado en estudios previos. Las ninas y ninos son representados con gran diferencia respecto a otros sectores poblacionales y se observo igualdad de presencia de mujeres y hombres independientemente de su edad. Con gran diferencia se representa un cuerpo entero vestido con ropa …

Froebel y los jardines de la infancia / por Pedro de Alcántara García

1874

Froebel y los jardines de la infancia

Polish is quantitatively different on quartzite flakes used on different worked materials.

2020

Metrology has been successfully used in the last decade to quantify use-wear on stone tools. Such techniques have been mostly applied to fine-grained rocks (chert), while studies on coarse-grained raw materials have been relatively infrequent. In this study, confocal microscopy was employed to investigate polished surfaces on a coarse-grained lithology, quartzite. Wear originating from contact with five different worked materials were classified in a data-driven approach using machine learning. Two different classifiers, a decision tree and a support-vector machine, were used to assign the different textures to a worked material based on a selected number of parameters (Mean density of furr…

Dense matter with eXTP

2019

In this White Paper we present the potential of the Enhanced X-ray Timing and Polarimetry (eXTP) mission for determining the nature of dense matter; neutron star cores host an extreme density regime which cannot be replicated in a terrestrial laboratory. The tightest statistical constraints on the dense matter equation of state will come from pulse profile modelling of accretion-powered pulsars, burst oscillation sources, and rotation-powered pulsars. Additional constraints will derive from spin measurements, burst spectra, and properties of the accretion flows in the vicinity of the neutron star. Under development by an international Consortium led by the Institute of High Energy Physics o…

Divergent Macroparasite Infections in Parapatric Swiss Lake-Stream Pairs of Threespine Stickleback (Gasterosteus aculeatus)

2015

Spatial heterogeneity in diversity and intensity of parasitism is a typical feature of most hostparasite interactions, but understanding of the evolutionary implications of such variation is limited. One possible outcome of infection heterogeneities is parasite-mediated divergent selection between host populations, ecotypes or species which may facilitate the process of ecological speciation. However, very few studies have described infections in populationpairs along the speciation continuum from low to moderate or high degree of genetic differentiation that would address the possibility of parasite-mediated divergent selection in the early stages of the speciation process. Here we provide…

Hybridization between mouse lemurs in an ecological transition zone in southern Madagascar

2009

Hybrid zones in ecotones can be useful model systems for the study of evolutionary processes that shape the distribution and discreteness of species. Such studies could be important for an improved understanding of the complex biogeography of Madagascar, which is renowned for its outstanding degree of small-scale endemism. Certain forest remnants in central Madagascar indicate that transitional corridors across the island could have connected microendemics in different forest types in the past. Evolutionary processes in such corridors are difficult to study because most of these corridors have disappeared due to deforestation in central Madagascar. We studied a hybrid zone in one of the few…