The aquatic biota of the now extinct lacustrine complex of the Mexico basin

The commonest organisms of the original Mexico lake complex are listed, including those that exist today in the Lago Viejo. In addition, a brief hydraulic history of this endorheic basin is given

Virtual Recruiting: The Impact of Virtual Interviews & Hiring Events on Construction Students

Recruitment from college construction programs was drastically altered by not being allowed to gather in person in large groups for the majority of 2020. Companies could no longer recruit in person as they had at past college events, and instead connected and communicated with students virtually. The construction management department at California Polytechnic State University San Luis Obispo (Cal Poly), bridged this gap between recruiting companies and current students, at a virtual career fair using a collaborative hub built on Microsoft Teams. Data was gathered from students via a survey after attending this first departmental virtual fair, to measure impacts or changes in their experiences as a result of the transition to a virtual setting. Students\u27 perceptions of the virtual career fair from the survey provided insight into the result that digitally required communication had on the student employer relationship, as well as other aspects of the recruitment process. Student recommendations, as well as existing research on regional career fairs, provide recommended improvements for possible virtual career fairs in the future

Confocal microscopic image sequence compression using vector quantization and 3D pyramids

The 3D pyramid compressor project at the University of Glasgow has developed a compressor for images obtained from CLSM device. The proposed method using a combination of image pyramid coder and vector quantization techniques has good performance at compressing confocal volume image data. An experiment was conducted on several kinds of CLSM data using the presented compressor compared to other well-known volume data compressors, such as MPEG-1. The results showed that the 3D pyramid compressor gave higher subjective and objective image quality of reconstructed images at the same compression ratio and presented more acceptable results when applying image processing filters on reconstructed images

Geotourism and local development based on geological and mining sites utilization, zaruma-portovelo, Ecuador

This study offers a detailed assessment of the geosites and mining sites present in the Zaruma-Portovelo mining district (Ecuador) through their qualitative and quantitative assessment. It shows up the potentiality of this area taking advantage of its geological-mining heritage. The methodological process includes: (i) compilation and inventory of all the sites within the study area with particular geological or mining interest; (ii) preparation of reports and thematic cartography, (iii) assessment and classification of the elements of geological-mining interest; (iv) SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis and TOWS (Threats, Opportunities, Weaknesses, Strengths) matrix preparation seeking strategies to guarantee the viability of geotourism. A total of 16 sites of geological interest and 11 of mining interest were identified. The 77% of these sites was proved to be of high and very high interest in scientific terms. Likewise, their susceptibility to degradation assessed from their vulnerability and fragility was found to be high or very high in the 30% of the cases. As for the protection priority, all the studied sites obtained a medium-high result. Finally, the study based on the SWOT-TOWS revealed the possibility of applying action strategies in order to facilitate the compatibility of geotourism with the current productive activities, despite the difficult situation in the study area created by mining activities

Opciones de productos a partir de la madera de acacia y su promoción : antecedentes de una experiencia con acacias en Chile

La investigación desarrollada por el Instituto Forestal (INFOR) ha generado la base para aprovechar la adaptabilidad que presentan en el país Acacia dealbata, Acacia mearnsii y A. melanoxylon, y su explotación como especies forestales alternativas para la producción de madera. Se ha investigado en las propiedades y aptitudes físico-mecánicas y pulpables de las especies para su uso en la industria del aserrío, tableros, pulpa y papel, y la identificación de las variables que inciden en el porcentaje de taninos obtenibles a partir de la corteza de A. mearnsii que crece en Chile. Este trabajo resume los resultados de la investigación emprendida por INFOR durante el desarrollo de los estudios referidos a los procesos industriales y aplicaciones de la madera.____________________________________Research studies carried out at Instituto Forestal (INFOR) have provided the basis for exploiting the adaptability of Acacia dealbata, A. mearnsii y A. melanoxylon to Chilean environments and its exploitation as an alternative forest species for wood production. The information has been generated about the properties and physical-mechanical aptitudes and pulpables of the species for its use in the industry of the Sawed wood, boards, pulp and paper, and the identification of the variables that impact in the percentage of attainable tannins starting from the bark of A. mearnsii in Chile. This work summarizes the results of the investigation undertaken by INFOR during the development of the studies referred to the industrial processes and applications of the wood

SHARDS: Constraints on the dust attenuation law of star-forming galaxies at z~2

We make use of SHARDS, an ultra-deep (<26.5AB) galaxy survey that provides optical photo-spectra at resolution R~50, via medium band filters (FWHM~150A). This dataset is combined with ancillary optical and NIR fluxes to constrain the dust attenuation law in the rest-frame NUV region of star-forming galaxies within the redshift window 1.5<z<3. We focus on the NUV bump strength (B) and the total-to-selective extinction ratio (Rv), targeting a sample of 1,753 galaxies. By comparing the data with a set of population synthesis models coupled to a parametric dust attenuation law, we constrain Rv and B, as well as the colour excess, E(B-V). We find a correlation between Rv and B, that can be interpreted either as a result of the grain size distribution, or a variation of the dust geometry among galaxies. According to the former, small dust grains are associated with a stronger NUV bump. The latter would lead to a range of clumpiness in the distribution of dust within the interstellar medium of star-forming galaxies. The observed wide range of NUV bump strengths can lead to a systematic in the interpretation of the UV slope ($\beta$) typically used to characterize the dust content. In this study we quantify these variations, concluding that the effects are $\Delta\beta$~0.4.Comment: 13 pages, 11+2 figures, 3 tables. MNRAS, in pres

Strain balanced quantum posts

Quantum posts are assembled by epitaxial growth of closely spaced quantum dot layers, modulating the composition of a semiconductor alloy, typically InGaAs. In contrast with most self-assembled nanostructures, the height of quantum posts can be controlled with nanometer precision, up to a maximum value limited by the accumulated stress due to the lattice mismatch. Here we present a strain compensation technique based on the controlled incorporation of phosphorous, which substantially increases the maximum attainable quantum post height. The luminescence from the resulting nanostructures presents giant linear polarization anisotropy.Comment: Submitted to Applied Physics Letters (7th March 2011). 4 pages, 4 figure

Charge control in laterally coupled double quantum dots

We investigate the electronic and optical properties of InAs double quantum dots grown on GaAs (001) and laterally aligned along the [110] crystal direction. The emission spectrum has been investigated as a function of a lateral electric field applied along the quantum dot pair mutual axis. The number of confined electrons can be controlled with the external bias leading to sharp energy shifts which we use to identify the emission from neutral and charged exciton complexes. Quantum tunnelling of these electrons is proposed to explain the reversed ordering of the trion emission lines as compared to that of excitons in our system.Comment: 4 pages, 4 figures submitted to PRB Rapid Com