A standardised method for measuring in situ denitrification in shallow aquifers: numerical validation and measurements in riparian wetlands

A tracer test to examine in situ denitrification in shallow groundwater by a piezometer with a packer system used bromide as a tracer of dilution and acetylene (10%) to block the denitrification process at the nitrous oxide stage. During the test, dissolved oxygen, nitrate (NO3-), bromide (Br-), nitrous oxide (N2O) and dissolved organic carbon (DOC) were measured. To calibrate the experimental method, comparison with numerical simulations of the groundwater transfer were carried out, taking into account the environmental characteristics. The method was tested by measurements undertaken in different environmental conditions (geology, land use and hydrology) in two riparian wetlands. Denitrification rates measured by this method ranged from 5.7 10-6 g N-NO3-L-1 h-1 to 1.97 10-3 g N-NO3-L-1 h-1 The method is applicable in shallow aquifers with a permeability from 10-2 to 10-4m s-1

Ferrocenyl gold complexes as efficient catalysts

More than half a century after the discovery of the ferrocene structure in 1951, it remains as a suitable building block in many research areas, including catalysis with the development of key chiral catalysts. On the other hand, gold-mediated catalysis has been raised in recent years, allowing the creation of a great variety of C-C bonds and C-heteroatom bonds. In this context, this review covers the recent advances made with the combination of these two iconic figures in the organometallic chemistry field, since the first gold catalyzed reaction using a ferrocene ligand reported in 1986. The combination of the excellent properties and versatility of this metallocene, has allowed the obtainment of a plethora of ligands for metal catalysis, although their use joined to gold catalysis is still scarcely explored

Wetland restoration and nitrate reduction: the example of the periurban wetland of Vitoria-Gasteiz (Basque Country, North Spain)

Changes in land use and agricultural intensification caused wetlands on the quaternary aquifer of Vitoria-Gasteiz (Basque Country) to disappear some years ago and nitrate concentration in groundwaters increased very quickly. The Basque Government recently declared the East Sector of this aquifer a Vulnerable Zone according to the 91/676/CEE European Directive. Recently, the wetlands have been restored through the closure of the main drainage ditches, the consequent elevation of the water table and the abondonment of agricultural practices near the wetlands. This is the case of the Zurbano wetland. Restoration has allowed the recovery of its biogeochemical function, which has reduced nitrate concentrations in waters. Nitrate concentrations which exceed 50 mg l–1 in groundwaters entering into the wetland are less than 10 mg l–1 at the outlet. Conditions in the wetland are conducive to the loss of nitrates: organic matter rich wetted soils, clay presence allowing a local semiconfined flow and very low hydraulic gradient. Water quality monitoring at several points around the wetland showed the processes involved in nitrate loss, although some aspects still remain unresolved. However, during storm events, the wetland effectively reduces the nitrate concentration entering the Alegria River, the most important river on the quaternary aquifer

The role of stellar radial motions in shaping galaxy surface brightness profiles

Aims. The physics driving features such as breaks observed in galaxy surface brightness (SB) profiles remains contentious. Here, we assess the importance of stellar radial motions in shaping their characteristics. Methods. We use the simulated Milky Way-mass cosmological discs from the Ramses Disc Environment Study (RaDES) to characterise the radial redistribution of stars in galaxies displaying type-I (pure exponentials), II (downbending), and III (upbending) SB profiles. We compare radial profiles of the mass fractions and the velocity dispersions of different sub-populations of stars according to their birth and current location. Results. Radial redistribution of stars is important in all galaxies regardless of their light profiles. Type-II breaks seem to be a consequence of the combined effects of outward-moving and accreted stars. The former produce shallower inner profiles (lack of stars in the inner disc) and accumulate material around the break radius and beyond, strengthening the break; the latter can weaken or even convert the break into a pure exponential. Further accretion from satellites can concentrate material in the outermost parts, leading to type-III breaks that can coexist with type-II breaks, but situated further out. Type-III galaxies would be the result of an important radial redistribution of material throughout the entire disc, as well as a concentration of accreted material in the outskirts. In addition, type-III galaxies display the most efficient radial redistribution and the largest number of accreted stars, followed by type-I and II systems, suggesting that type-I galaxies may be an intermediate case between types-II and III. In general, the velocity dispersion profiles of all galaxies tend to flatten or even increase around the locations where the breaks are found. The age and metallicity profiles are also affected, exhibiting different inner gradients depending on their SB profile, being steeper in the case of type-II systems (as found observationally). The steep type-II profiles might be inherent to their formation rather than acquired via radial redistribution

Sport Injuries in School and Extracurricular Activities in the Community of Madrid (Spain)

Este estudio tuvo como objetivo analizar la epidemiología lesional deportiva de las actividades desarrolladas bajo responsabilidad docente (Educación Física, recreo y actividades extraescolares) en centros de Educación Secundaria Obligatoria (ESO). Participaron 1.050 estudiantes (edad media 13,9 ± 1,3 años) que cumplimentaron un cuestionario sobre lesiones deportivas. De las 848 lesiones registradas en total, 319 (172 en chicos y 147 en chicas) ocurrieron en actividades desarrolladas bajo responsabilidad docente (0,30 lesiones/estudiante). Las actividades extraescolares fueron el ámbito con mayor promedio de lesiones (0,12 por estudiante). Se observó una mayor incidencia lesional a los 13 años y una menor probabilidad de que las lesiones ocurriesen en los chicos (OR = 0,64 (0,49-0,85); p < 0,05). Los esguinces y las contusiones fueron las lesiones más frecuentes, especialmente en tobillo y rodilla. Un 27,3% de las lesiones impidieron al alumnado participar activamente en las sesiones de Educación Física durante más de tres díasThis study aimed to analyse the epidemiology of sport injuries that occurred during activities performed under teacher supervision (Physical Education, break and extracurricular activities), at high school. A questionnaire regarding sport injuries were administered to 1050 students (mean age 13.9 ± 1.3 years). Out of the 848 sport injuries registered, 319 (172 in boys and 147 in girls) took place during activities performed under teacher supervision, (0.30 injuries/student). Extracurricular activities were the scenario in which the highest injury rate (0.12) was observed. There was a higher incidence of injury at age 13 and a lower likelihood of injuries occurring in boys (OR = 0.64 (0.49-0.85); p < 0.05). Sprains and contusions were the type of injury most frequently observed, especially in areas such as ankles and knees. A total of 27.3% of the injuries reported prevented the students from actively participating in the Physical Education sessions for more than three day

Assessing math anxiety in elementary schoolchildren through a Spanish version of the Scale for Early Mathematics Anxiety (SEMA)

Math anxiety (MA) affects students of all age groups. Because of its effects on children’s academic development, the need to recognize its early manifestations has been highlighted. We designed a European-Spanish version of the Scale for Early Mathematics Anxiety (SEMA; Wu et al. (2012)), and assessed its psychometric properties in a sample of children aged 7 to 12 years. The participants (967 typically developing children) were elementary school students recruited from ten schools. Children reported their general and math anxiety levels in an individual session and performed nonverbal IQ and math abilities subtests in a group session. Teachers reported the final math grades. The psychometric indices obtained, and the resulting factor structure revealed that the European-Spanish version of the SEMA developed in this study is a reliable and valid measure to evaluate MA in children from 3rd to 6th grade. Moreover, we explored gender differences, that resulted in small effect sizes, which disappeared when controlling for trait anxiety. Differences across grades were found for both global MA and the numerical processing anxiety factor but not for the situational and performance anxiety factor. Finally, MA was negatively associated with students’ math achievement, although the strength of the associations varied with the MA measure selected, the kind of math achievement analyzed, and the school stage considered. Our findings highlight the relevance of MA in elementary school and highlight the need for an early identification of students at risk of suffering MA to palliate the negative consequences of MA in children’s cognitive and academic development