A proof of uniqueness of the Gurarii space

We present a short and elementary proof of isometric uniqueness of the Gurarii space.Comment: 6 pages, some improvements incorporate

Metronidazole photodegradation under solar light with UiO-66-NH2 photocatalyst: Mechanisms, pathway, and toxicity assessment

Metronidazole is a nitroimidazole antibiotic that is increasingly detected in aquatic bodies. Therefore, there is an urgent need to research methodologies to remove this and other antibiotics. One of the alternatives is the application of solar photocatalysis, which requires the use of an efficient photocatalyst. In this work, UiO-66-NH2 was synthesized by a facile solvothermal method and evaluated for the degradation of metronidazole under simulated solar light. The effects of catalyst dosage, initial pH, and metronidazole concentration were discussed, establishing the best operation conditions. In addition, the stability and reproducibility of UiO-66-NH2 activity were also verified. The quenching reaction showed that holes and superoxide radicals coexisted as the main active species, being responsible for the metronidazole degradation. The pathway of metronidazole photodegradation was proposed by means of density functional theory calculations and LC/ESI-MS analysis. It is noteworthy that this study detected for the first time C6H11N3O4, C4H6N2O3, and C4H8N2O4 as metronidazole photodegradation byproducts. ECOSAR toxicity analysis showed that all byproducts were less toxic than the original metronidazole, supporting the potential feasibility of this method for treating water polluted with this antibioticThis work was supported by the National State Research Agency of Spain (project number: PID2019–106186RB-I00/AEI/10.13039/ 501100011033). Yilan Wang acknowledges the financial support provided by China Scholarship Council (CSC No. 201908610198). The authors sincerely acknowledged support from the external services of the Autonomous University of Madrid (SIdI

Effect of Defoliation Frequency and Planting Density on Yield and Nutritive Value of \u3ci\u3eCoursetia ferruginea\u3c/i\u3e (HBK) Lavin

The aim of the present study was to asses the influence of the frequency of defoliation and density of sowing on yield and nutritive value of Coursetia ferruginea. Three defoliation frequencies (6, 8 and 10 weeks) and three densities of planting (1 x 1 m, 1 x 1.5 m and 1 x 2 m) were evaluated. A randomized block design, in a split plot arrangement and four repetitions, was used. Frequency of defoliation has a strong significant (P\u3c 0.01) effect on dry matter (DM) yield (13.6, 18.1 and 27.8 g DM/plant for 6, 8 and 10-week defoliation frequencies), plant height (63.5, 76.6 and 101.2 cm) and plant survival (71, 74 and 86%). Nutritive value was significantly (P\u3c 0.05) affected by the frequency of defoliation. Mineral content was reduced as the defoliation interval increased. Density of planting did not affect (P\u3e 0.05) any of the variables. It is concluded that, C. ferruginea is a forage shrub with potential to improve animal feed quality, but it does not stand frequent defoliation

MEGARA main optics opto-mechanics

MEGARA is the future integral-field and multi-object spectrograph for the GTC 10.4m telescope located in the Observatorio del Roque de los Muchachos in La Palma. INAOE is a member of the MEGARA Consortium and it is in charge of the Optics Manufacturing work package. In addition to the manufacturing of 73 elements, the work package includes the opto-mechanics i.e. the opto-mechanical design, manufacture, tests and integration of the complete assembly of the main optics composed by the collimator and camera subsystems. MEGARA passed the Optics Detailed Design Review in May 2013 and will have the Detailed Design Review of the complete instrument early 2014. Here we describe the detailed design of the collimator and camera barrels. We also present the finite elements models developed to simulate the behavior of the barrel, sub-cells and other mechanical elements. These models verify that the expected stress fields and the gravitational displacements on the lenses are compatible with the optical quality tolerances. The design is finished and ready for fabrication

From Construction Workers to Architects: Developing Scientific Research Capacity in Low-Income Countries

Solving global health challenges in a sustainable manner depends on explicitly addressing scientific capacity-building needs, as well as establishing long-term, meaningful partnerships with colleagues in the developing world

Within-group behavioral variation promotes biased task performance and the emergence of a defensive caste in a social spider

The social spider Anelosimus studiosus exhibits a behavioral polymorphism where colony members express either a passive, tolerant behavioral tendency (social) or an aggressive, intolerant behavioral tendency (asocial). Here we test whether asocial individuals act as colony defenders by deflecting the suite of foreign (i.e., heterospecific) spider species that commonly exploit multi-female colonies. We (1) determined whether the phenotypic composition of colonies is associated with foreign spider abundance, (2) tested whether heterospecific spider abundance and diversity affect colony survival in the field, and (3) performed staged encounters between groups of A. studiosus and their colony-level predator Agelenopsis emertoni (A. emertoni)to determine whether asocial females exhibit more defensive behavior. We found that larger colonies harbor more foreign spiders, and the number of asocial colony members was negatively associated with foreign spider abundance. Additionally, colony persistence was negatively associated with the abundance and diversity of foreign spiders within colonies. In encounters with a colony-level predator, asocial females were more likely to exhibit escalatory behavior, and this might explain the negative association between the frequency of asocial females and the presence of foreign spider associates. Together, our results indicate that foreign spiders are detrimental to colony survival, and that asocial females play a defensive role in multi-female colonies

Weather at Sierra Negra: 7.3-year statistics and a new method to estimate the temporal fraction of cloud cover

Sierra Negra, one of the highest peaks in central Mexico, is the site of the Large Millimeter Telescope. We describe the first results of a comprehensive analysis of the weather data measured in situ from October 2000 to February 2008 to be used as a reference for future activity in the site. We compare the data from two different stations at the summit considering the accuracy of both instruments. We analysed the diurnal, seasonal and annual cycles for all the parameters. The thermal stability is remarkably good, crucial for a good performance of the telescopes. From the solar radiation data we developed a new method to estimate the fraction of time when the sky is clear of clouds. We show that our measurements are consistent with a warm standard atmosphere model. The conditions at the site are benign and stable given its altitude, showing that Sierra Negra is a extremely good site for millimeter and high energy observations.Comment: Accepted, MNRAS, 17 pages, 26 figure file