Testing GeoGebra as an effective tool to improve the understanding of the concept of limit on engineering students

The impact GeoGebra on the teaching of the concept of limit was analyzed. Two groups of engineering students, studying differential calculus, served as control and test groups. The traditional teaching, based on examples solved by hand, was given to the control group while a series of activities involving the usage of the mathematical software GeoGebra were applied in an attempt of improving the degree of assimilation on the concept of limits

Efficacy of a self-applied online program to promote resilience and coping skills in university students in four Spanish-speaking countries: study protocol for a randomized controlled trial

Background: There is evidence of a high prevalence of depression and anxiety in university students. Therefore, college time is a key period where prevention of mental disorders through interventions that promote resilience and mental health can be relevant. Currently, there are interventions available, but these are insufficient for those who need them. Online interventions are tools that can facilitate global accessibility and are easy for young people to use. CORE (Cultivating Our Resilience) is a self-administered online program, based on Ryff’s psychological well-being model, to promote resilience and coping skills in university students at risk of developing symptoms of depression or anxiety. The objective is to evaluate the effectiveness of this intervention protocol in comparison with an active control condition targeting healthy lifestyle, and a waiting list control condition. The study will be conducted in four populations of Spanish-speaking university students (Spain, Argentina, Colombia, and Mexico). Methods: The study design is a randomized controlled trial (RCT). At least 324 university students will be randomly assigned to three conditions: 1) CORE, a 6-week training program to improve resilience; 2) HLP, a 6-week training to promote a healthy lifestyle; and 3) WL, waiting list control condition. The primary outcome measure will be the Connor-Davidson resilience scale. Additionally, measures of anxiety, depression, quality of life and socio-demographic variables (age, sex, incomes, marital status, among others) will be collected. Participants will be evaluated at pre-treatment, after each module, 6 weeks after allocation, and at 3-month follow-up. Intention-to-treat and per-protocol analyses will be performed. Discussion: The results of this study will contribute to research on Internet-administered interventions and the implementation of a protocol that includes a series of components designed to improve resilience and coping skills, increase psychological well-being, and prevent depression and anxiety disorders in Spanish-speaking university students. In addition, avenues will be opened up for new research on the effectiveness of these interventions focused on the prevention and promotion of mental health in Spanish-speaking countries

Antarctic network of lamp-calibrated multichannel radiometers for continuous ozone and uv radiation data

International audienceThree NILU-UV multichannel radiometers have been installed in 1999 at the Argentinian sites of Ushuaia (54S), Marambio (64S) and Belgrano-II (77S) in order to continuously monitor UV radiation, photosynthetically active radiation and total ozone. The measurements were established by INM, Spain in collaboration with FMI, Finland, DNA-IAA, Argentina and CADIC, Argentina to observe and characterize the spatial and temporal evolution of ozone and ultraviolet radiation in the Antarctic region. Special attention has been given to the quality control and quality assurance of the measurements under harsh climatological conditions. The ozone and UV time series of 2000?2006 were calibrated using a polynomial fit for lamp measurements performed every second week all year round. The gaps in these data are minimal, with almost no data missing, and the data products are available from http://www.polarvortex.org in near real time. The data products include the erythemally-weighted UV, UVB and UVA radiation, photosynthetically active radiation (PAR), total ozone (O3) and a cloud parameter (CLT). For UV data, dose rates as well as daily doses are available; from these the maximum measured UV indices (UVI), during 2000?2006, were 12.0, 9.7 and 8.1 at Ushuaia, Marambio and Belgrano-II, respectively

ASPECTOS ECOLÓGICOS DE LA POLUCIÓN ATMOSFÉRICA: ESTUDIO DE CASOS EN LA REGIÓN DE MURCIA

The most outstanding aspects fo air pollution have been hibliographically revised: the influence of the physical environment, polluting sources and ecological effects on hiogeochemical cycles and living organisms, as well as economic and legal factors. Special attention has been paid to the incidente of a region's capacity to support air pollution. in relation to ist hysical environment and land planning. This study has approached two remarkable regional cases in SE Spain: Cartagena and the urban agglomeration of Murcia and its surroundings.Se revisan bibliográficamente los aspectos ecológicos más de5tacados de la polución atmosférica, con especial referencia a la influencia de las características del medio físico, los efectos ecológicos en los ciclos biogeoquímicos y organismos vivos, así como los factores económico\ y legales. Se presta especial atención a la incidencia de la potencialidad de un territorio a la polución atmosférica, en relación con los estudios del medio físico y el planeamiento territorial. Se ejemplifica el estudio en dos casos regionales contrastados y de marcado interés: Cartagena y la aglomeraci0n urbana de Murcia y alrededores

C-GOALS II. Chandra Observations of the Lower Luminosity Sample of Nearby Luminous Infrared Galaxies in GOALS

We analyze Chandra X-ray observatory data for a sample of 63 luminous infrared galaxies (LIRGs), sampling the lower-infrared luminosity range of the Great Observatories All-Sky LIRG survey (GOALS), which includes the most luminous infrared selected galaxies in the local universe. X-rays are detected for 84 individual galaxies within the 63 systems, for which arcsecond resolution X-ray images, fluxes, infrared and X-ray luminosities, spectra and radial profiles are presented. Using X-ray and MIR selection criteria, we find AGN in (31$\pm$5)% of the galaxy sample, compared to the (38$\pm$6)% previously found for GOALS galaxies with higher infrared luminosities (C-GOALS I). Using mid-infrared data, we find that (59$\pm$9)% of the X-ray selected AGN in the full C-GOALS sample do not contribute significantly to the bolometric luminosity of the host galaxy. Dual AGN are detected in two systems, implying a dual AGN fraction in systems that contain at least one AGN of (29$\pm$14)%, compared to the (11$\pm$10)% found for the C-GOALS I sample. Through analysis of radial profiles, we derive that most sources, and almost all AGN, in the sample are compact, with half of the soft X-ray emission generated within the inner $\sim 1$ kpc. For most galaxies, the soft X-ray sizes of the sources are comparable to those of the MIR emission. We also find that the hard X-ray faintness previously reported for the bright C-GOALS I sources is also observed in the brightest LIRGs within the sample, with $L_{\rm FIR}>8\times10^{10}$ L$_{\odot}$.Comment: 24 pages, 13 figures, 11 tables, accepted for publication in A&

A Compton-thick nucleus in the dual AGN of Mrk 266

We present results of our analysis of NuSTAR data of the luminous infrared galaxy Mrk 266, which contains two nuclei, SW and NE, resolved in previous Chandra imaging. Combining with the Chandra data, we intepret the hard X-ray spectrum obtained from a NuSTAR observation as resulting from steeply rising flux from a Compton-thick AGN in the SW nucleus which is very faint in the Chandra band, confirming the previous claim of Mazzarella et al. (2012). This hard X-ray component is dominated by reflection, and its intrinsic 2-10 keV luminosity is likely to be ~1e43 erg/s. Although it is bright in soft X-ray, only moderately absorbed NE nucleus has a 2-10 keV luminosity of 4e41 erg/s, placing it in the low-luminosity AGN class. These results have implications for understanding the detectability and duty cycles of emission from dual AGN in heavily obscured mergers.Comment: Accepted for publication in Astronomy and Astrophysics. 7 pages, 5 figures. Language corrections and a minor correction in Fig. 5 include

Mass Distribution in Hickson Compact Groups of Galaxies

This study presents the mass distribution for a sample of 18 late-type galaxies in nine Hickson Compact Groups. We used rotation curves from high resolution 2D velocity fields of Fabry-Perot observations and J-band photometry from the 2MASS survey, in order to determine the dark halo and the visible matter distributions. The study compares two halo density profile, an isothermal core-like distribution and a cuspy one. We also compare their visible and dark matter distributions with those of galaxies belonging to cluster and field galaxies coming from two samples: 40 cluster galaxies of Barnes et al (2004) and 35 field galaxies of Spano et al. (2008). The central halo surface density is found to be constant with respect to the total absolute magnitude similar to what is found for the isolated galaxies. This suggests that the halo density is independent to galaxy type and environment. We have found that core-like density profiles fit better the rotation curves than cuspy-like ones. No major differences have been found between field, cluster and compact group galaxies with respect to their dark halo density profiles.Comment: 35 pages, 21 figures. Accept for publication in Astronomical Journa

Integrating pressure sensor control into semi-solid extrusion 3D printing to optimize medicine manufacturing

Semi-solid extrusion (SSE) is a three-dimensional printing (3DP) process that involves the extrusion of a gel or paste-like material via a syringe-based printhead to create the desired object. In pharmaceuticals, SSE 3DP has already been used to manufacture formulations for human clinical studies. To further support its clinical adoption, the use of a pressure sensor may provide information on the printability of the feedstock material in situ and under the exact printing conditions for quality control purposes. This study aimed to integrate a pressure sensor in an SSE pharmaceutical 3D printer for both material characterization and as a process analytical technology (PAT) to monitor the printing process. In this study, three materials of different consistency were tested (soft vaseline, gel-like mass and paste-like mass) under 12 different conditions, by changing flow rate, temperature, or nozzle diameter. The use of a pressure sensor allowed, for the first time, the characterization of rheological properties of the inks, which exhibited temperature-dependent, plastic and viscoelastic behaviours. Controlling critical material attributes and 3D printing process parameters may allow a quality by design (QbD) approach to facilitate a high-fidelity 3D printing process critical for the future of personalized medicine

A Compton-thick nucleus in the dual active galactic nuclei of Mrk 266

We present the results from our analysis of NuSTAR data of the luminous infrared galaxy Mrk 266, which contains two nuclei, south-western (SW) and north-eastern (NE), which were resolved in previous Chandra imaging. Combining this with the Chandra data, we intepret the hard X-ray spectrum obtained from a NuSTAR observation to result from a steeply rising flux from a Compton-thick active galactic nuclei (AGN) in the SW nucleus which is very faint in the Chandra band, confirming the previous claim. This hard X-ray component is dominated by reflection, and its intrinsic 2–10 keV luminosity is likely to be ∼1 × 10⁴³ erg s⁻¹. Although it is bright in soft X-ray, only a moderately absorbed NE nucleus has a 2–10 keV luminosity of 4 × 10⁴¹ erg s⁻¹, placing it in the low-luminosity AGN class. These results have implications for understanding the detectability and duty cycles of emission from dual AGN in heavily obscured mergers