Asymptotic Behaviour for a Class of Non-monotone Delay Differential Systems with Applications

The paper concerns a class of n-dimensional non-autonomous delay differential equations obtained by adding a non-monotone delayed perturbation to a linear homogeneous cooperative system of ordinary differential equations. This family covers a wide set of models used in structured population dynamics. By exploiting the stability and the monotone character of the linear ODE, we establish sufficient conditions for both the extinction of all the populations and the permanence of the system. In the case of DDEs with autonomous coefficients (but possible time-varying delays), sharp results are obtained, even in the case of a reducible community matrix. As a sub-product, our results improve some criteria for autonomous systems published in recent literature. As an important illustration, the extinction, persistence and permanence of a non-autonomous Nicholson system with patch structure and multiple time-dependent delays are analysed.Ministerio de Economía, Industria y Competitividad /FEDER (MTM2015-66330)Fundaçao para a Ciencia e a Tecnologia under project UID/MAT/-04561/201

Photoplethysmographic Waveform Versus Heart Rate Variability to Identify Low Stress States. Attention Test

Our long-term goal is the development of an automatic identifier of attentional states. In order to accomplish it, we should firstly be able to identify different states based on physiological signals. So, the first aim of this work is to identify the most appropriate features, to detect a subject high performance state. For that, a database of electrocardiographic (ECG) and photopletysmographic (PPG) signals is recorded in two unequivocally defined states (rest and attention task) from up to 50 subjects as a sample of the population. Time and frequency parameters of heart/pulse rate variability have been computed from the ECG/PPG signals respectively. Additionally, the respiratory rate has been estimated from both signals and also six morphological parameters from PPG. In total, twenty six features are obtained for each subject. They provide information about the autonomic nervous system and the physiological response of the subject to an attention demand task. Results show an increase of sympathetic activation when the subjects perform the attention test. The amplitude and width of the PPG pulse were more sensitive that the classical sympathetic markers (normalised power in LF and LF/HF ratio) for identifying this attentional state. State classification accuracy reaches a mean of 89 $\pm$ 2%, a maximum of 93% and a minimum of 85%, in the hundred classifications made by only selecting four parameters extracted from the PPG signal (pulse amplitude, pulse width, pulse downward slope and mean pulse rate). These results suggest that attentional states could be identified by PPG

A World Wide Web-Based Practice That Disseminates Photogrammetry. Inspiring secondary students to pursue geomatics careers

This is the accepted version of a manuscript published in IEEE Geoscience and Remote Sensing Magazine. ISSN: 2168-6831. https://doi.org/10.1109/MGRS.2018.2876565The D3MOBILE Metrology World League was established in 2013 with the aim of encouraging curiosity and interest in science, and particularly geoscience, in the secondary students of grades ISCED 1 and 2. Presented as an international championship, D3MOBILE introduces students to the discipline of photogrammetry through the e-learning methodology concept. The use of well-known technologies by the pupils, such as their own mobile devices (smartphones or tablets), allows us to develop educational procedures that are attractive and challenging for them. All the work that we propose for the participants is presented in a scientific, technical, and professional language but in a more interactive format than traditional textbooks or theoretical classes. The proposed challenges provide students with the opportunity to establish their own learning objectives, work as a team and take responsibility for their work. This paper addresses the experience, from an educational perspective, carried out by our research group CIGEO (Civil Engineering and Geomatics) during the organization of the first five editions of this international “concept submission competition”. During this period, we tried to create and improve a project-based learning (PBL) methodology that can be adapted to e-learning and daily classwork at the high school level, which can be easily implemented regardless of the number of participants and can be implemented anywhere in the world. The obtained results demonstrate the potential of alternative teaching methods combined with new technologies to engage students in science learning and improve the perception of the geosciences as a job opportunityWe thankfully acknowledge the financial support from FECYT—Ministerio de Economía y Competitividad (FCT 12-3495; FCT 13-5961; FCT 14-8038; FCT 15-9481); and Xunta de Galicia (ED431B22016/030; ED341DR2016/023). We would also like to thank our large number of sponsors and collaborators: Universia, BQ, Autodesk, National Geographic Institute (IGN), City Council of Lugo, Provincial Council of Lugo, Spanish Center of Metrology (CEM), Fundación Vodafone, CEAPA, City Council of La Coruña, Fundación Barrié, ANPE, CSI-F, Fundación Comforp, PCE, Univ. Tecnológica Nacional (Argentina), Fundacion Mujeres, EDUCACION 3.0. and likely even more entities. Finally, we would like to thank the schoolteachers and students whose work and dedication allowed this project to achieve its objectivesS

The Future Professionals in Geomatics

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A PBeL for training non-experts in mobile-based photogrammetry and accurate 3-D recording of small-size/non-complex objects

The high level of automation, user-friendliness and cost-effectiveness of photogrammetry have contributed significantly to its popularisation among amateur users in recent years. Paradoxically, this situation poses challenges when relying on the accuracy of the derived 3-D products requiring control procedures to be implemented. In this context, we present a case study of the D3Mobile project: a fully online competition for participants worldwide funded by the International Society of Photogrammetry and Remote Sensing (ISPRS). The aim is for participants to obtain reality-based 3-D models using their own mobile phones and to critically examine the metric accuracy that hides behind the beguiling realism of photogrammetry. The relative precision of the former participants’ models reached values around 1:2,000, proportionally to the object size. These results provide an idea of the current level of development of photogrammetry and the potential it offers for any kind of user after proper capacity building and trainingS

Diatom and vegetation responses to Late Glacial and Early Holocene climate changes at Lake Estanya (Southern Pyrenees, NE Spain)

We investigate Lake Estanya's diatom and pollen records from the Late Glacial (LG) to the Early Holocene (EH), in order to compare limnological and vegetation responses to common climate forcing. The biotic changes recognized in this study largely agree with the hydrological evolution of the lake described previously for the same period. The diatom record shows high sensitivity to fluctuations in both lake level and salinity concentration as consequence of climate shifts. In addition vegetation results indicate that the area could have played an important role as regional vegetation refuge. Shallow lake conditions during the Last Glacial Maximum (LGM) were punctuated by relatively deeper freshwaters between 19.3 and 18.6 cal kyr BP and at 18.0 cal kyr BP, as recorded by diatom shifts. A subsequent increasing aridity trend, coinciding with the Mystery Interval (MI), affected the diatom accumulation rates, which dropped to its minimum values between 17.2 to 14.7 cal kyr BP. Particularly dry and cold conditions during the LGM and MI are supported by the largest values of steppic pollen taxa of the whole sequence, which account for up to 40%. However, relatively high values of Betula during the Heinrich Event 1 suggest a plausible regional vegetation refuge. Abrupt cooling and warming episodes within the LG triggered remarkable ecological threshold crossings in the diatom communities, especially during the stadial/interstadial episodes. At this point, the vegetation reflect the onset of warm conditions during the Bølling/Allerød with the partial substitution of Betula by Marcescent and Evergreen Quercus, what probably indicates the arrival of temperate taxa to the area and the likely migration of birch to higher altitudes. The Younger Dryas Stadial shows a complex ecological response. Diatoms are very poorly preserved, but aquatic taxa reach their highest values. An increase in Marcescent Quercus during this cold stage lends further support to the hypothesis that this is a regional vegetation refuge. Low lake levels recorded during the EH affected the development and preservation of diatom communities. A delay in the onset of humid conditions for the EH is also supported by the vegetation composition, characterized by the maximum expansion of Juniperus

Maximal superintegrability on N-dimensional curved spaces

A unified algebraic construction of the classical Smorodinsky-Winternitz systems on the ND sphere, Euclidean and hyperbolic spaces through the Lie groups SO(N+1), ISO(N), and SO(N,1) is presented. Firstly, general expressions for the Hamiltonian and its integrals of motion are given in a linear ambient space $R^{N+1}$, and secondly they are expressed in terms of two geodesic coordinate systems on the ND spaces themselves, with an explicit dependence on the curvature as a parameter. On the sphere, the potential is interpreted as a superposition of N+1 oscillators. Furthermore each Lie algebra generator provides an integral of motion and a set of 2N-1 functionally independent ones are explicitly given. In this way the maximal superintegrability of the ND Euclidean Smorodinsky-Winternitz system is shown for any value of the curvature.Comment: 8 pages, LaTe