Investigación

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Documentos generados por los docentes e investigadores de la Universidad en su labor de investigación científica producida o editada por los departamentos y centros de la Universitat Politècnica de València.

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A decision analysis framework for stakeholder involvement and learning in groundwater management
(European Geosciences Union (EGU), 2013) Karjalainen, T.P.; Rossi, P. M.; Ala-aho, P.; Eskelinen, R.; Reinikainen, K.; Klove, B.; Pulido Velázquez, Manuel Augusto; Yang, H.; Dpto. de Ingeniería Hidráulica y Medio Ambiente; Instituto Universitario de Ingeniería del Agua y del Medio Ambiente; Escuela Técnica Superior de Ingeniería de Caminos, Canales y Puertos; European Commission; Academy of Finland
[EN] Multi-criteria decision analysis (MCDA) methods are increasingly used to facilitate both rigorous analysis and stakeholder involvement in natural and water resource planning. Decision making in that context is often complex and multi-faceted with numerous trade-offs between social, environmental and economic impacts. However, practical applications of decision-support methods are often too technically oriented and hard to use, understand or interpret for all participants. The learning of articipants in these processes is seldom examined, even though successful deliberation depends on learning. This paper analyzes the potential of an interactive MCDA framework, the decision analysis interview (DAI) approach, for facilitating stakeholder involvement and learning in groundwater management. It evaluates the results of an MCDA process in assessing land-use management alternatives in a Finnish esker aquifer area where conflicting land uses affect the groundwater body and dependent ecosystems. In the assessment process, emphasis was placed on the interactive role of the MCDA tool in facilitating stakeholder participation and learning. The results confirmed that the structured decision analysis framework can foster learning and collaboration in a process where disputes and diverse interests are represented. Computer-aided interviews helped the participants to see how their preferences affected the desirability and ranking of alternatives. During the process, the participants knowledge and preferences evolved as they assess their initial knowledge with the help of fresh scientific information. The decision analysis process led to the opening of a dialogue, showing the overall picture of the problem context, and the critical issues for the further process.
Active learning and social commitment projects as a teaching-learning intervention in engineering degrees
(Editorial Universitat Politècnica de València, 2019-07-05) Pernía-Espinoza, Alpha; Sanz-Garcia, Andres; Martinez-de-Pison-Ascacibar, F. Javier; Peciña-Marqueta, Sergio; Blanco-Fernandez, Julio; Academy of Finland
[EN] The purpose of universities, apart from produce qualified professionals with problem-solving capabilities and soft-skills, should be to develop the social responsibility sense on their students. In this context, our proposal combines project based learning (PBL) and service based learning (SBL) along with gamming and the use of open-source machines, with the aim to increase student’s motivation and their social commitment with an affordable budget. The strategy, from now on named OS-PBL-SR (Open-Source-based PBL projects with Social Responsibility), mainly includes three important aspects: (i) assignment with projects orientated towards a social benefit; (ii) development of the projects using open-source Do It Yourself desktop machines (DIY-DkM); and (iii) include gamming in the evaluation method. The strategy was applied in the subject Manufacturing Technology but it might be easily exportable to other technical subjects. The results from the last academic year are presented. Also, a new OS-PBL-SR proposal aimed to the design and fabrication of autonomy-oriented products for people in a dependency situation is presented. The results showed the beneficial impact on undergraduate students by keeping high levels of motivation reflected on excellent success rates and scores. In addition, essential advantages in the use of DIY-DkM were found regarding the implementation of this kind of PBL strategy.
Antipsychotic and benzodiazepine use and brain morphology in schizophrenia and affective psychoses - Systematic reviews and birth cohort study
(Elsevier, 2018) Huhtaniska, Sanna; korkala, Likka; Heikka, Tuomas; Björnholm, Lassi; Lehtiniemi, Heli; Hulkko, Anja P.; Moilanen, Jani S.; Tohka, Jussi; Manjón Herrera, José Vicente; Coupé, Pierrick; Kiviniemi, Vesa; Isohanni, Matti; Koponen, Hannu; Murray, Graham K.; Miettunen, Jouko; Dpto. de Física Aplicada; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Técnica Superior de Ingeniería Informática; Academy of Finland
[EN] The aim of this paper was to investigate differences in brain structure volumes between schizophrenia and affective psychoses, and whether cumulative lifetime antipsychotic or benzodiazepine doses relate to brain morphology in these groups. We conducted two systematic reviews on the topic and investigated 44 schizophrenia cases and 19 with affective psychoses from the Northern Finland Birth Cohort 1966. The association between lifetime antipsychotic and benzodiazepine dose and brain MRI scans at the age of 43 was investigated using linear regression. Intracranial volume, sex, illness severity, and antipsychotic/benzodiazepine doses were used as covariates. There were no differences between the groups in brain structure volumes. In schizophrenia, after adjusting for benzodiazepine dose and symptoms, a negative association between lifetime antipsychotic dose and the nucleus accumbens volume remained. In affective psychoses, higher lifetime benzodiazepine dose associated with larger volumes of total gray matter and hippocampal volume after controlling for antipsychotic use and symptoms. It seems that in addition to antipsychotics, the severity of symptoms and benzodiazepine dose are also associated with brain structure volumes. These results suggest, that benzodiazepine effects should also be investigated also independently and not only as a confounder.
Assessing bi-directional effects on the diurnal cycle of measured solar-induced chlorophyll fluorescence in crop canopies
(Elsevier, 2020-12-15) Zhang, Zhaoying; Zhang, Yongguang; Zhang, Qian; Chen, Jing M.; Porcar-Castell, Albert; Guanter Palomar, Luis María; Wu, Yunfei; Zhang, Xiaokang; Wang, Hezhou; Ding, Dawei; Li, Zhongyang; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Ingeniería del Agua y del Medio Ambiente; Academy of Finland; China Scholarship Council; Deutsche Forschungsgemeinschaft; National Natural Science Foundation of China; National Key Research and Development Program of China; Scientific Innovation Research of College Graduate in Jiangsu Province of China
[EN] Solar-induced chlorophyll fluorescence (SIF) has shown to be a good proxy of gross primary production (GPP) across multiple spatial and temporal scales. The dependence of top-of-canopy measurements of SIF on the illumination and observation directions has been recognized as an important factor in the relationship between SIF and GPP across multiple spatiotemporal scales. In this study, we investigated angular effects in diurnal observed SIF (SIFobs) measurements taken with a multi-angle SIF measuring system in a wheat-corn rotational field during the growing season of 2018. Our results reveal strong angular dependencies in diurnal measurements of top-of-canopy SIF for both red SIF obs (RSIFobs) and far-red SIFobs (FRSIFobs). We also observe that the correlation between SIF obs (RSIF obs and FRSIFobs) and GPP depends on both the illumination and viewing directions. To mitigate angular effects in SIFobs, an approach based on spectral reflectance measurements was used. The derived canopy total SIF emission (SIFtotal) at both red and far-red bands (RSIFtotal and FRSIFtotal) showed less angular dependencies and stronger relationships to APAR and GPP than RSIFobs and FRSIFobs. These results highlight the important role of angular effects in SIF when interpreting directional SIF obs retrievals from space, which normally include large variations in sun-target-viewing geometries. This study contributes to our understanding of angular effects on SIF-GPP relationships and subsequently help improve the estimation of GPP from SIF data.
Assessment of microproject-based teaching/learning (MicroPBL) experience in industrial engineering degrees
(Editorial Universitat Politècnica de València, 2017-06-26) Pernía-Espinoza, Alpha; Sodupe-Ortega, Enrique; Martinez-de-Pison-Ascacibar, Fco. Javier; Urraca-Valle, Ruben; Antoñanzas-Torres, Javier; Sanz-García, Andres; Universidad de La Rioja; Fundación Banco Santander; Academy of Finland
[EN] An assessment program to evaluate microproject-based teaching/learning (MicroPBL) methodology on the technical subject ‘Manufacturing Technology’ was implemented for four consecutive academic years. Students from three different engineering degrees were involved providing feedback through different surveys that allowed us to perform a proper evaluation. More specifically, students’ surveys were anonymous after each academic year, except the last one, in which non-anonymous pre and post-surveys were conducted. The surveys were meant to evaluate the acquisition of specific competences (using technical questions about the subject) as well as generic competences (using questions concerning soft-skills). We also checked the students’ satisfaction with the methodology and with the signature in general. Using non-anonymous surveys allowed us to correlate results with the student’s final scores. Students’ self-assessment concerning their knowledge about technical aspects drastically changed after the course. The average of the subject’s final score from student’s perception was slightly higher than the actual value. Student’s self-perception on soft-skills was also increased at the end of the course. The MicroPBL methodology demonstrated beneficial for the case of this technical subject as it maintained high motivation levels in students, which were directly related to students’ success rates and final scores.
Breeding dispersal strategies following reproductive failure explain low apparent survival of immigrant Temminck's stints
(Nordic Ecological Society, 2011-04) Pakanen, Veli-Matti; Hilden, Olavi; Ronka, Antti; Belda Pérez, Eduardo Jorge; Luukkonen, Aappo; Kvist, Laura; Koivula, Kari; Dpto. de Ciencia Animal; Escuela Politécnica Superior de Gandia; Instituto de Investigación para la Gestión Integrada de Zonas Costeras; Maj and Tor Nessling Foundation; Academy of Finland; Kone Foundation; University of Oulu; Finnish Cultural Foundation; Finnish Environment Institute
In some animal populations, immigrants have lower survival than philopatric individuals. Costs of dispersal or low phenotypic quality of dispersers may explain the pattern. However, apparent adult survival estimates, which describe real survival combined with site fidelity cannot be separated from permanent emigration. Thus, heterogeneity in breeding dispersal propensities of immigrants and philopatrics can bias fitness correlates of dispersal. Differences in breeding dispersal propensities may be caused by different strategies in response to environmental cues inducing dispersal, such as reproductive success. In such cases, the reported differences between immigrants and philopatric individuals may not reflect true variation in survival. We studied whether dispersal status specific apparent adult survival is associated with reproductive success in a Temminck's stint Calidris temminckii population. We analysed two long term capture-recapture datasets characterised by low and high nest predation levels. Philopatric individuals had higher apparent adult survival than immigrants in both datasets and the difference was highlighted during the high nest predation period. By contrasting return rates between successful and unsuccessful breeders as a proxy for dispersal, we found that unsuccessful immigrants breeding for the first time dispersed more likely than successful immigrants, but such a pattern was not found among philopatric individuals. Our results support the hypothesis that immigrant and philopatric individuals have different breeding dispersal strategies following reproductive failure and that their apparent adult survival differences are at least partly explained by different breeding dispersal propensities. Our results also suggest that the recent decline of the study population reflects a multiple response to increased nest predation through decreased local recruitment and increased emigration. © 2011 The Authors.
Coherently Time-Varying Metasurfaces
(American Physical Society, 2022-06-24) Mostafa, M.H.; Díaz Rubio, Ana; Mirmoosa, M.S.; Tretyakov, S.A.; Dpto. de Comunicaciones; Instituto Universitario de Tecnología Nanofotónica; Escuela Politécnica Superior de Gandia; Academy of Finland; Ministerio de Educación y Formación Profesional
[EN] Known coherent metasurfaces control the interference of waves of a given frequency with other coherent waves at the same frequency, either illuminating from a different direction or created as intermodulation products. In this paper, we introduce a class of metasurfaces that are modulated in time coherently with the illuminating radiation. Such modulation opens a possibility to control reflection, absorption, and transmission at multiple frequencies, including illuminations by two or more incoherent waves. In particular, we study dynamic resistive layers and show how to use them to design thin multifrequency perfect absorbers that overcome the bandwidth limit for static linear absorbers. Furthermore, we demonstrate possibilities of remote tuning of the absorption level. We hope that this work opens up alternative avenues in wave engineering using coherent modulation of metasurface parameters.
Complexity-preserving simulations among three variants of accepting networks of evolutionary processors
(Springer Verlag (Germany), 2011-03) Bottoni ., Paolo; Labella ., Anna; Manea ., Florin; Mitrana, Víctor; Petre ., Ion; Sempere Luna, José María; Dpto. de Sistemas Informáticos y Computación; Escuela Técnica Superior de Ingeniería Informática; Instituto Universitario Valenciano de Investigación en Inteligencia Artificial; Ministerio de Educación y Ciencia; Academy of Finland; Alexander von Humboldt Foundation
In this paper we consider three variants of accepting networks of evolutionary processors. It is known that two of them are equivalent to Turing machines. We propose here a direct simulation of one device by the other. Each computational step in one model is simulated in a constant number of computational steps in the other one while a translation via Turing machines squares the time complexity. We also discuss the possibility of constructing simulations that preserve not only complexity, but also the shape of the simulated network. © 2011 Springer Science+Business Media B.V.
Cyclosporin A-loaded dissolving microneedles for dermatitis therapy: Development, characterisation and efficacy in a delayed-type hypersensitivity in vivo model
(Springer, 2024-03) Martínez-Navarrete, Miquel; Guillot, Antonio Jose; Lobita, Maria C.; Recio, Maria Carmen; Giner, Rosa; Aparicio-Blanco, Juan; Montesinos-Mezquita, María Carmen; Santos, Helder A.; Melero, Ana; Academy of Finland; European Commission; Generalitat Valenciana; Ministerio de Universidades; Agencia Estatal de Investigación; European Regional Development Fund
[EN] Several drugs can be used for treating inflammatory skin pathologies like dermatitis and psoriasis. However, for the management of chronic and long-term cases, topical administration is preferred over oral delivery since it prevents certain issues due to systemic side effects from occurring. Cyclosporin A (CsA) has been used for this purpose; however, its high molecular weight (1202 Da) restricts the diffusion through the skin structure. Here, we developed a nano-in-micro device combining lipid vesicles (LVs) and dissolving microneedle array patches (DMAPs) for targeted skin delivery. CsA-LVs allowed the effective incorporation of CsA in the hydrophilic DMAP matrix despite the hydrophobicity of the drug. Polymeric matrix composed of poly (vinyl alcohol) (5% w/v), poly (vinyl pyrrolidine) (15% w/v) and CsA-LV dispersion (10% v/v) led to the formation of CsA-LVs@DMAPs with adequate mechanical properties to penetrate the stratum corneum barrier. The safety and biocompatibility were ensured in an in vitro viability test using HaCaT keratinocytes and L929 fibroblast cell lines. Ex vivo permeability studies in a Franz-diffusion cell setup showed effective drug retention in the skin structure. Finally, CsA-LVs@DMAPs were challenged in an in vivo murine model of delayed-type hypersensitivity to corroborate their potential to ameliorate skin inflammatory conditions. Different findings like photon emission reduction in bioluminescence study, normalisation of histological damage and decrease of inflammatory cytokines point out the effectivity of CsA-LVs@DMAPs to treat these conditions. Overall, our study demonstrates that CsA-LVs@DMAPs can downregulate the skin inflammatory environment which paves the way for their clinical translation and their use as an alternative to corticosteroid-based therapies.
Long-term antipsychotic and benzodiazepine use and brain volume changes in schizophrenia: The Northern Finland Birth Cohort 1966 study
(Elsevier, 2017-08-30) Huhtaniska, Sanna; Jaaskelainen, Erika; Heikka, Tuomas; Moilanen, Jani S.; Lehtiniemi, Heli; Tohka, Jussi; Manjón Herrera, José Vicente; Coupe, Pierrick; Bjornholm, Lassi; Koponen, Hannu; Veijola, Juha; Isohanni, Matti; Kiviniemi, Vesa; Murray, Graham K.; Miettunen, Jouko; Dpto. de Física Aplicada; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Técnica Superior de Ingeniería Informática; Banco Santander; Academy of Finland; University of Oulu; Orion Research Foundation; Sigrid Jusélius Foundation; Universidad Carlos III de Madrid; Jalmari and Rauha Ahokas Foundation; Brain and Behavior Research Foundation; Ministerio de Economía y Competitividad; Ministerio de Educación, Cultura y Deporte
[EN] High doses of antipsychotics have been associated with loss in cortical and total gray matter in schizophrenia. However, previous imaging studies have not taken benzodiazepine use into account, in spite of evidence suggesting adverse effects such as cognitive impairment and increased mortality. In this Northern Finland Birth Cohort 1966 study, 69 controls and 38 individuals with schizophrenia underwent brain MRI at the ages of 34 and 43 years. At baseline, the average illness duration was over 10 years. Brain structures were delineated using an automated volumetry system, volBrain, and medication data on cumulative antipsychotic and benzodiazepine doses were collected using medical records and interviews. We used linear regression with intracranial volume and sex as covariates; illness severity was also taken into account. Though both medication doses associated to volumetric changes in subcortical structures, after adjusting for each other and the average PANSS total score, higher scan-interval antipsychotic dose associated only to volume increase in lateral ventricles and higher benzodiazepine dose associated with volume decrease in the caudate nucleus. To our knowledge, there are no previous studies reporting associations between benzodiazepine dose and brain structural changes. Further studies should focus on how these observations correspond to cognition and functioning.
Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits
(Linnean Society of London, 2016-07) Lemoine, Melissa; Lucek, Kay; Perrier, Charles; Saladin, Verena; Adriaensen, Frank; Barba Campos, Emilio; Belda Pérez, Eduardo Jorge; Charmantier, Anne; Cichón, Mariusz; Eeva, Tapio; Grégoire, Arnaud; Hinde, Camilla A.; Johnsen, Arild; Komdeur, Jan; Mänd, Raivo; Dpto. de Ciencia Animal; Escuela Politécnica Superior de Gandia; Instituto de Investigación para la Gestión Integrada de Zonas Costeras; Ministerio de Ciencia e Innovación; Swiss National Science Foundation; Agence Nationale de la Recherche, Francia; Academy of Finland; Estonian Ministry of Science and Education; Hungarian Scientific Research Fund; Netherlands Organization for Scientific Research; Netherlands Genomics Initiative; Fundação para a Ciência e a Tecnologia, Portugal
Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing population genetic structure at different spatial scales is thus a crucial step towards understanding mechanisms underlying intraspecific differentiation and diversification. Here, we studied the population genetic structure of a highly mobile species - the great tit Parus major - at different spatial scales. We analysed 884 individuals from 30 sites across Europe including 10 close-by sites (< 50 km), using 22 microsatellite markers. Overall we found a low but significant genetic differentiation among sites (F-ST = 0.008). Genetic differentiation was higher, and genetic diversity lower, in south-western Europe. These regional differences were statistically best explained by winter temperature. Overall, our results suggest that great tits form a single patchy metapopulation across Europe, in which genetic differentiation is independent of geographical distance and gene flow may be regulated by environmental factors via movements related to winter severity. This might have important implications for the evolutionary trajectories of sub-populations, especially in the context of climate change, and calls for future investigations of local differences in costs and benefits of philopatry at large scales. (C) 2016 The Linnean Society of London
Makerspaces in Higher Education: the UR-Maker experience at the University of La Rioja
(Editorial Universitat Politècnica de València, 2017-06-26) Pernía-Espinoza, Alpha; Sodupe-Ortega, Enrique; Peciña-Marqueta, Sergio; Martínez-Bañares, Sergio; Sanz-Garcia, Andres; Blanco-Fernandez, Julio; Academy of Finland
[EN] According to the CDIO (Conceive-Design-Implement-Operate) Syllabus, apart from technical knowledge, labour markets are demanding engineers with personal, interpersonal and system building skills. The current educational system, however, is based on teaching theoretical concepts rather than on practical activities. Makerspaces could become a bridge between universities and industry, particularly in STEM (Science, Technology, Engineering and Math) carriers. Makerspaces, also known as hackerspaces, hack labs and fab labs, are open-access spaces where a community shares tools, machines and knowledge in order to implement an idea. This communication reviews the makerspaces at the world’s top 10 engineering universities and three of the most recognized in Spain. The qualitative data was collected through the universities’ websites. We observed that most of the reviewed universities have outstanding makerspaces for engineering students, generally open to the entire university community. In Spain, the ‘Maker UPV’ was found exceptionally successful in activities and projects performed in spite of their lack of material resources. Lastly, the authors describe their experience implementing a campus makerspace at the University of La Rioja, sharing interesting information about the organization, budget, funding and activities.
Multikernel Clustering via Non-Negative Matrix Factorization Tailored Graph Tensor Over Distributed Networks
(Institute of Electrical and Electronics Engineers, 2021-07) Ren, Zhenwen; Mukherjee, Mithun; Bennis, Mehdi; Lloret Mauri, Jaime; Dpto. de Comunicaciones; Escuela Politécnica Superior de Gandia; Instituto de Investigación para la Gestión Integrada de Zonas Costeras; Academy of Finland; Natural Science Foundation of Chongqing; Southwest University of Science and Technology, China; Science and Technology Department of Zhejiang Province; Sichuan Province Science and Technology Support Program; Department of Science and Technology of Sichuan Province
[EN] Next-generation wireless networks are witnessing an increasing number of clustering applications, and produce a large amount of non-linear and unlabeled data. In some degree, single kernel methods face the challenging problem of kernel choice. To overcome this problem for non-linear data clustering, multiple kernel graph-based clustering (MKGC) has attracted intense attention in recent years. However, existing MKGC methods suffer from two common problems: (1) they mainly aim to learn a consensus kernel from multiple candidate kernels, slight affinity graph learning, such that cannot fully exploit the underlying graph structure of non-linear data; (2) they disregard the high-order correlations between all base kernels, which cannot fully capture the consistent and complementary information of all kernels. In this paper, we propose a novel non-negative matrix factorization (NMF) tailored graph tensor MKGC method for non-linear data clustering, namely TMKGC. Specifically, TMKGC integrates NMF and graph learning together in kernel space so as to learn multiple candidate affinity graphs. Afterwards, the high-order structure information of all candidate graphs is captured in a 3-order tensor kernel space by introducing tensor singular value decomposition based tensor nuclear norm, such that an optimal affinity graph can be obtained subsequently. Based on the alternating direction method of multipliers, the effective local and distributed solvers are elaborated to solve the proposed objective function. Extensive experiments have demonstrated the superiority of TMKGC compared to the state-of-the-art MKGC methods.
NABS: non-local automatic brain hemisphere segmentation
(Elsevier, 2015-05) Romero Gómez, José Enrique; Manjón Herrera, José Vicente; Tohka, Jussi; Coupé, Pierrick; Robles Viejo, Montserrat; Dpto. de Física Aplicada; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Escuela Técnica Superior de Ingeniería Informática; Academy of Finland; Agence Nationale de la Recherche, Francia; Ministerio de Ciencia e Innovación
In this paper, we propose an automatic method to segment the five main brain sub-regions (i.e. left/right hemispheres, left/right cerebellum and brainstem) from magnetic resonance images. The proposed method uses a library of pre-labeled brain images in a stereotactic space in combination with a non-local label fusion scheme for segmentation. The main novelty of the proposed method is the use of a multi-label block-wise label fusion strategy specifically designed to deal with the classification of main brain sub-volumes that process only specific parts of the brain images significantly reducing the computational burden. The proposed method has been quantitatively evaluated against manual segmentations. The evaluation showed that the proposed method was faster while producing more accurate segmentations than a current state-of-the-art method. We also present evidences suggesting that the proposed method was more robust against brain pathologies than the compared method. Finally, we demonstrate the clinical value of our method compared to the state-of-the-art approach in terms of the asymmetry quantification in Alzheimer's disease.
On the Integration of Reconfigurable Intelligent Surfaces in Real-World Environments: A Convenient Approach for Estimation Reflection and Transmission.
(Institute of Electrical and Electronics Engineers, 2022-08) Díaz Rubio, Ana; Kosulnikov, Sergei; Tretyakov, Sergei; Dpto. de Comunicaciones; Instituto Universitario de Tecnología Nanofotónica; Escuela Politécnica Superior de Gandia; Academy of Finland; European Commission; Ministerio de Educación y Formación Profesional
[EN] The use of reconfigurable intelligent surfaces (RISs) foroptimization of propagation channels is one of the most promising and revolutionizing techniques for improving efficiency of the next generation of communications systems. In this article, we combine physical optics approximation and the theory of diffraction gratings to study the scattering properties of finite-size metasurfaces mounted on partially reflecting walls. We consider both reflective and refractive metasurfaces designed to control both the reflection and transmission of waves. We start the analysis under the assumption of uniform, plane-wave illumination, and then discuss nonuniform illuminations by directive antennas.
Perfect control of reflection and refraction using spatially dispersive metasurfaces
(American Physical Society, 2016-08-19) Asadchy, V.S.; Albooyeh, M.; Tcvetkova, S. N.; Díaz Rubio, Ana; Ra'di, Y.; Tretyakov, S.A.; Dpto. de Comunicaciones; Instituto Universitario de Tecnología Nanofotónica; Escuela Politécnica Superior de Gandia; Academy of Finland
[EN] Nonuniform metasurfaces (electrically thin composite layers) can be used for shaping refracted and reflected electromagnetic waves. However, known design approaches based on the generalized refraction and reflection laws do not allow realization of perfectly performing devices: there are always some parasitic reflections into undesired directions. In this paper we introduce and discuss a general approach to the synthesis of metasurfaces for full control of transmitted and reflected plane waves and show that perfect performance can be realized. The method is based on the use of an equivalent impedance matrix model which connects the tangential field components at the two sides on the metasurface. With this approach we are able to understand what physical properties of the metasurface are needed in order to perfectly realize the desired response. Furthermore, we determine the required polarizabilities of the metasurface unit cells and discuss suitable cell structures. It appears that only spatially dispersive metasurfaces allow realization of perfect refraction and reflection of incident plane waves into arbitrary directions. In particular, ideal refraction is possible only if the metasurface is bianisotropic (weak spatial dispersion), and ideal reflection without polarization transformation requires spatial dispersion with a specific, strongly nonlocal response to the fields.
Population dynamics of an expanding passerine at the distribution margin
(Wiley-Blackwell, 2012-03) Karvonen, Juhani; Orell, Markku; Rytkönen, Seppo; Broggi, Juli; Belda Pérez, Eduardo Jorge; Dpto. de Ciencia Animal; Escuela Politécnica Superior de Gandia; Instituto de Investigación para la Gestión Integrada de Zonas Costeras; Academy of Finland
Individuals may be maladapted to novel environments at the species' distribution margin. We investigated population dynamics in a marginal habitat where reproduction has been proven poor. Survival, population growth rate (¿) and its components, breeding and natal dispersal were studied in great tits Parus major breeding at the northern margin of its distribution in northern Finland. We used long term capture-mark-recapture data sets. Study area size and population density were used to explain adult survival rates. The average annual estimates of adult survival rose from 0.371 to 0.388 between the periods of 1971-1984 and 1999-2009. The estimates are slightly lower than estimates of small passerines in Europe. Low local survival rate of fledglings (0.050-0.055) probably reflects intensified emigration from this low quality area. Temporal variation in ¿ was large (0.498-1.856). Despite of low adult survival and recruitment rates, the mean estimates of ¿ (1.008 and 1.033) indicate an overall stability in the population size. Indeed, our results suggest that the immigration has an important role in the population dynamics of northern great tits. Thus the population is demographically and genetically dependent on core habitats which may cause adaptive problems due to intensive gene flow. Given those limitations, options for evolution of local adaptations in northern distribution margins are discussed.
Reduction of structural impacts and distinction of photosynthetic pathways in a global estimation of GPP from space-borne solar-induced chlorophyll fluorescence
(Elsevier, 2020-04) Zhang, Zhaoying; Zhang, Yongguang; Porcar-Castell, Albert; Joiner, Joanna; Guanter Palomar, Luis María; Yang, Xi; Migliavacca, Mirco; Ju, Weimin; Sun, Zhigang; Chen, Shiping; Martini, David; Zhang, Qian; Li, Zhaohui; Cleverly, James; Wang, Hezhou; Goulas, Yves; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Ingeniería del Agua y del Medio Ambiente; National Science Foundation, China; National Key Research and Development Program of China; National Science Foundation, EEUU; National Natural Science Foundation of China; Alexander von Humboldt Foundation; Scientific Innovation Research of College Graduate in Jiangsu Province of China; Academy of Finland; United States Department of Agriculture, Agricultural Research Service
[EN] Quantifying global photosynthesis remains a challenge due to a lack of accurate remote sensing proxies. Solar-induced chlorophyll fluorescence (SIF) has been shown to be a good indicator of photosynthetic activity across various spatial scales. However, a global and spatially challenging estimate of terrestrial gross primary production (GPP) based on satellite SIF remains unresolved due to the confounding effects of species-specific physical and physiological traits and external factors, such as canopy structure or photosynthetic pathway (C-3 or C-4). Here we analyze an ensemble of far-red SIF data from OCO-2 satellite and ground observations at multiple sites, using the spectral invariant theory to reduce the effects of canopy structure and to retrieve a structure-corrected total canopy SIF emission (SIFtotal). We find that the relationships between observed canopy-leaving SIF and ecosystem GPP vary significantly among biomes. In contrast, the relationships between SIFtotal and GPP converge around two unique models, one for C-3 and one for C-4 plants. We show that the two single empirical models can be used to globally scale satellite SIF observations to terrestrial GPP. We obtain an independent estimate of global terrestrial GPP of 129.56 +/- 6.54 PgC/year for the 2015-2017 period, which is consistent with the state-of-the-art data- and process-oriented models. The new GPP product shows improved sensitivity to previously undetected 'hotspots' of productivity, being able to resolve the double-peak in GPP due to rotational cropping systems. We suggest that the direct scheme to estimate GPP presented here, which is based on satellite SIF, may open up new possibilities to resolve the dynamics of global terrestrial GPP across space and time.
Searches for Neutrinos in the Direction of Radio-bright Blazars with the ANTARES Telescope
(American Astronomical Society, 2024-03-01) Albert, A.; Alves, S.; Andre, M.; Ardid Ramírez, Miguel; Ardid Ramírez, Joan Salvador; Aubert, J.J.; Aublin, J.; Baret, B.; Basa, S.; Becherini, Y.; Belhorma, B.; Bendahman, M.; Benfenati, F.; Bertin, V.; Biagi, S.; Bissinger, M.; Martínez Mora, Juan Antonio; Poirè, Chiara; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Politécnica Superior de Gandia; Instituto de Investigación para la Gestión Integrada de Zonas Costeras; Academy of Finland; European Commission; Generalitat Valenciana; Conseil Régional d'Alsace; Agencia Estatal de Investigación; National Science Foundation, EEUU; European Regional Development Fund; Ministerio de Ciencia e Innovación; Instituto Nazionale di Fisica Nucleare; Arab Fund for Economic and Social Development; Conseil Régional Provence-Alpes-Côte d'Azur; Netherlands Organization for Scientific Research; National Aeronautics and Space Administration, EEUU; Centre National de la Recherche Scientifique, Francia; Bundesministerium für Bildung und Forschung, Alemania; Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Francia; Executive Agency for Higher Education, Scientific Research, Development and Innovation Funding, Rumanía; Ministère de l'Education Nationale, de la Formation professionnelle, de l'Enseignement Supérieur et de la Recherche Scientifique, Marruecos
[EN] Active galaxies, especially blazars, are among the most promising extragalactic candidates for high-energy neutrino sources. To date, ANTARES searches included these objects and used GeV-TeV gamma-ray flux to select blazars. Here, a statistically complete blazar sample selected by their bright radio emission is used as the target for searches of origins of neutrinos collected by the ANTARES neutrino telescope over 13 yr of operation. The hypothesis of a neutrino-blazar directional correlation is tested by pair counting and a complementary likelihood-based approach. The resulting posttrial p-value is 3.0% (2.2 sigma in the two-sided convention). Additionally, a time-dependent analysis is performed to search for temporal clustering of neutrino candidates as a means of detecting neutrino flares in blazars. None of the investigated sources alone reaches a significant flare detection level. However, the presence of 18 sources with a pretrial significance above 3 sigma indicates a p = 1.4% (2.5 sigma in the two-sided convention) detection of a time-variable neutrino flux. An a posteriori investigation reveals an intriguing temporal coincidence of neutrino, radio, and gamma-ray flares of the J0242+1101 blazar at a p = 0.5% (2.9 sigma in the two-sided convention) level. Altogether, the results presented here suggest a possible connection of neutrino candidates detected by the ANTARES telescope with radio-bright blazars.
The effect of mission duration on LISA science objectives
(Springer-Verlag, 2022-01) Amaro Seoane, Pau; Arca Sedda, Manuel; Babak, Stanislav; Berry, Christopher P. L.; Berti, Emanuele; Bertone, Gianfranco; Blas, Diego; Bogdanovic, Tamara; Bonetti, Matteo; Breivik, Katelyn; Brito, Richard; Caldwell, Robert; Capelo, Pedro R.; Caprini, Chiara; Cardoso, Vitor; Dpto. de Matemática Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Instituto Universitario de Matemática Multidisciplinar; Academy of Finland; European Commission; Owens Family Foundation; Alfred P. Sloan Foundation; National Science Foundation, EEUU; European Cooperation in Science and Technology; Fundação para a Ciência e a Tecnologia, Portugal; National Aeronautics and Space Administration, EEUU; Science and Technology Facilities Council, Reino Unido; Ministero dell'Istruzione, dell'Università e della Ricerca
[EN] The science objectives of the LISA mission have been defined under the implicit assumption of a 4-years continuous data stream. Based on the performance of LISA Pathfinder, it is now expected that LISA will have a duty cycle of ¿0.75, which would reduce the effective span of usable data to 3 years. This paper reports the results of a study by the LISA Science Group, which was charged with assessing the additional science return of increasing the mission lifetime. We explore various observational scenarios to assess the impact of mission duration on the main science objectives of the mission. We find that the science investigations most affected by mission duration concern the search for seed black holes at cosmic dawn, as well as the study of stellar-origin black holes and of their formation channels via multi-band and multi-messenger observations. We conclude that an extension to 6 years of mission operations is recommended.

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