The Effect of Environmental Features, Self-Avatar, and Immersion on Object Location Memory in Virtual Environments

One potential application for virtual environments (VEs) is the training of spatial knowledge. A critical question is what features the VE should have in order to facilitate this training. Previous research has shown that people rely on environmental features, such as sockets and wall decorations, when learning object locations. The aim of this study is to explore the effect of varied environmental feature fidelity of VEs, the use of self-avatars, and the level of immersion on object location learning and recall. Following a between-subjects experimental design, participants were asked to learn the location of three identical objects by navigating one of the three environments: a physical laboratory or low and high detail VE replicas of this laboratory. Participants who experienced the VEs could use either a head-mounted display (HMD) or a desktop computer. Half of the participants learning in the HMD and desktop systems were assigned a virtual body. Participants were then asked to place physical versions of the three objects in the physical laboratory in the same configuration. We tracked participant movement, measured object placement, and administered a questionnaire related to aspects of the experience. HMD learning resulted in statistically significant higher performance than desktop learning. Results indicate that, when learning in low detail VEs, there is no difference in performance between participants using HMD and desktop systems. Overall, providing the participant with a virtual body had a negative impact on performance. Preliminary inspection of navigation data indicates that spatial learning strategies are different in systems with varying levels of immersion

Development of organic fertilizers from food market waste and urban gardening by composting in Ecuador

Currently, the management of urban waste streams in developing countries is not optimized yet, and in many cases these wastes are disposed untreated in open dumps. This fact causes serious environmental and health problems due to the presence of contaminants and pathogens. Frequently, the use of specific low-cost strategies reduces the total amount of wastes. These strategies are mainly associated to the identification, separate collection and composting of specific organic waste streams, such as vegetable and fruit refuses from food markets and urban gardening activities. Concretely, in the Chimborazo Region (Ecuador), more than 80% of municipal solid waste is dumped into environment due to the lack of an efficient waste management strategy. Therefore, the aim of this study was to develop a demonstration project at field scale in this region to evaluate the feasibility of implanting the composting technology not only for the management of the organic waste fluxes from food market and gardening activities to be scaled-up in other developing regions, but also to obtain an end-product with a commercial value as organic fertilizer. Three co-composting mixtures were prepared using market wastes mixed with pruning of trees and ornamental palms as bulking agents. Two piles were created using different proportions of market waste and prunings of trees and ornamental palms: pile 1 (50:33:17) with a C/N ratio 25; pile 2: (60:30:10) with C/N ratio 24 and pile 3 (75:0:25) with C/N ratio 33), prepared with market waste and prunings of ornamental palm. Throughout the process, the temperature of the mixtures was monitored and organic matter evolution was determined using thermogravimetric and chemical techniques. Additionally, physico-chemical, chemical and agronomic parameters were determined to evaluate compost quality. The results obtained indicated that all the piles showed a suitable development of the composting process, with a significant organic matter decomposition, reached in a shorter period of time in pile 3. At the end of the process, all the composts showed absence of phytotoxicity and suitable agronomic properties for their use as organic fertilizers. This reflects the viability of the proposed alternative to be scaled-up in developing areas, not only to manage and recycle urban waste fluxes, but also to obtain organic fertilizers, including added value in economic terms related to nutrient contents.Peer ReviewedPostprint (published version

High temperature effects in mortar and concrete specimens using a meso-mechanical model with fracture based zero-thickness interface elements

This paper describes recent numerical simulation results of a purely mechanical study of the effects of high temperature in mortar and concrete. The material has been considered as a two-phase composite, with different thermal expansion laws of matrix and particles taken from the literature. The numerical simulation is based on a meso-mechanical model developed in the group of Mechanics of Materials UPC, which represents the largest aggregate particles explicitly, and represent cracks in a discrete manner by inserting zerothickness interface elements in all potential crack trajectories a priori of the analysis. The differential expansions create tensile stresses and therefore cracking, that eventually may close, reopen and lead to non-trivial overall material behavior. The results are discussed and compared to the experimental information available, and lead to a general good agreement, capturing the essential mechanisms described in the literature

Adaptation of Cu(In, Ga)Se2 photovoltaics for full unbiased photocharge of integrated solar vanadium redox flow batteries

The integration of photovoltaics and vanadium redox flow batteries (VRFBs) is a promising alternative for the direct conversion and storage of solar energy in a single device, considering their inherent higher energy density versus other redox pairs. However, this integration is not seamless unless the photovoltaic system is customized to the voltage needs of the battery, which unlike artificial photosynthesis, continuously increase with the state-of-charge. We have developed an integrated solar VRFB with adapted low-cost Cu(In, Ga)Se2 modules of 3 and 4 series-connected cells (solar efficiency of mini-solar module 8.1%), and considering the voltage requirements (1.3-1.6 V), we have evaluated the influence of the photovoltaic operation region on the final efficiency of the solar VRFB. Full unbiased photocharge under 1 Sun illumination has been achieved resulting in high energy (77%), solar-to-charge (7.5%) and overall round trip energy conversion efficiencies (5.0%) exceeding the values reported in the literature for other solar VRFBs, thus demonstrating the feasibility and intrinsic potential of adapting low-cost commercial photovoltaics to such energy storage systems

Photocatalytic hydrogen evolution using bi-metallic (Ni/Pt) Na2Ti3O7 whiskers: Effect of the deposition order

Photocatalytic hydrogen production through ethanol photo-reforming using Na2Ti3O7 whiskers increases if the sodium titanate is decorated with well-known metallic catalysts such as Ni and Pt. Whereas wet impregnation with nickel gives only a slight increase in the activity, photo-deposition of Pt increased the H2 production by more than one order of magnitude. Through the combination of both co-catalysts (Ni and Pt) a superior performance in terms of H2 production is further observed. However, hydrogen yield is largely enhanced (almost three-fold), up to 778 μmol·g−1·h−1, if the Pt is photo-deposited on the surface of the catalyst before wet impregnation with Ni species (NTO/Pt/Ni) compared to H2 yield (283 μmol·g−1·h−1) achieved with the catalyst prepared in the reverse order (NTO/Ni/Pt). Structural, morphological, optical, and chemical characterization was carried out in order to correlate physicochemical properties with their photocatalytic activity. The X-ray photoelectron spectroscopy (XPS) results show a higher concentration of Pt2+ species if this metallic layer is under the nickel oxide layer. Moreover, X-ray diffraction patterns (XRD) show that Na2Ti3O7 surface is modified for both metal decoration processes

Complexin has a dual synaptic function as checkpoint protein in vesicle priming and as a promoter of vesicle fusion

The presynaptic SNARE-complex regulator complexin (Cplx) enhances the fusogenicity of primed synaptic vesicles (SVs). Consequently, Cplx deletion impairs action potential-evoked transmitter release. Conversely, though, Cplx loss enhances spontaneous and delayed asynchronous release at certain synapse types. Using electrophysiology and kinetic modeling, we show that such seemingly contradictory transmitter release phenotypes seen upon Cplx deletion can be explained by an additional of Cplx in the control of SV priming, where its ablation facilitates the generation of a "faulty" SV fusion apparatus. Supporting this notion, a sequential two-step priming scheme, featuring reduced vesicle fusogenicity and increased transition rates into the faulty primed state, reproduces all aberrations of transmitter release modes and short-term synaptic plasticity seen upon Cplx loss. Accordingly, we propose a dual presynaptic function for the SNARE-complex interactor Cplx, one as a "checkpoint" protein that guarantees the proper assembly of the fusion machinery during vesicle priming, and one in boosting vesicle fusogenicity

Sodium Hyaluronate-Induced Ocular Hypertension in Rats Damages the Direction-Selective Circuit and Inner/Outer Retinal Plexiform Layers

Purpose: To assess the changes in retinal morphology in a rat model of chronic glaucoma induced by ocular hypertension. Methods: Intraocular pressure (IOP) was surgically increased through weekly injections of sodium hyaluronate (HYA) in the anterior eye chamber of the left eye of male Wistar rats, whereas the right eyes were sham operated (salt solution). During the 10-week experimental period, IOP was measured weekly with a rebound tonometer. Retinal cryosections were prepared for histological/immunohistochemical analysis and morphometry. Results: IOP was higher in HYA-treated eyes than in sham-operated eyes along the 10-week period, which was significant from the fourth to the nineth week. Ocular hypertension in HYA-treated eyes was associated with morphologic and morphometric changes in bipolar cells, ON-OFF direction-selective ganglion cells, ON/OFF starburst amacrine cells, and inner plexiform layer sublamina. Conclusions: Serial HYA treatment in the rat anterior eye chamber results in mild-to-moderate elevated and sustained IOP and ganglion cell death, which mimics most human open-angle glaucoma hallmarks. The reduced number of direction-selective ganglion cells and starburst amacrine cells accompanied by a deteriorated ON/OFF plexus in this glaucoma model could lend insight to the abnormalities in motion perception observed in patients with glaucoma.Supported by the Spanish Ministry of Science and Innovation (MICINN-FEDER PID2019-106230RB-I00), 2), Institute of Health Carlos III (General Subdirection of Networks and Cooperative Research Centers RETICs OFTARED 2012-2021) co-financed by the European Regional Development fund (RD16/0008/0016 [Alicante] and RD16/0008/0022 [Valencia]), Asociación Retina Asturias (ASOCIACIONRETINA1-20I), Generalitat Valenciana (IDIFEDER/2017/064), and the Research funds from both Department of Surgery (Ophthalmology Unit) and Cellular-Molecular Ophthalmobiology Group of the University of Valencia (Spain)

Estudio epidemiológico en una muestra clínica de mujeres a través del dis

La investigación epidemiológica llevada a cabo en las últimas décadas en nuestro país ha demostrado, de manera inequívoca, la existencia de marcadas diferencias en la morbilidad psicopatológica y en el patrón de conducta de enfermedad desarrollados según el sexo (Vázquez-Barquero, Diez Manrique, Peña, Quintanal y Labrador López, 1986; Herrera, Antonell, Espagnolo, Domenech y Martín, 1987; Herrera, Antonell, Spagnolo y Gispert, 1990). Este hecho, unido a la constatación de que la prevalencia psicopatológica en la mujer es mucho mayor que en el hombre y que el riesgo de padecer un trastorno mental puede ser casi del doble en el sexo femenino (Muñoz, 1979; Herrera et al., 1987; Vázquez-Barquero, Diez Manrique y Peña, 1987), nos hacen plantear la presente investigación con el objetivo de conocer el tipo de desórdenes psicológicos que afectan de forma preferente a la población femenina, objetivo éste enmarcado en un planteamiento metodológico de tipo epidemiológico descriptivo

Estandarización nacional del método de conductividad eléctrica para analizar el vigor de semillas en girasol

Objetivos del IIPAAS: Objetivo general: Validar a nivel nacional el test de conductividad eléctrica para medir el vigor en semillas de girasol. Objetivos específicos: 1. Confirmar la clasificación del vigor en base al test de CE propuesta en los estudios precedentes. 2. Evaluar la exactitud, reproducibilidad y repetibilidad del test de CE entre y dentro de los laboratorios participantes. 3. Confeccionar un protocolo nacional como paso previo para ser propuesto al Comité de Vigor de la ISTA

Controlling the electrochemical hydrogen generation and storage in graphene oxide by in-situ Raman spectroscopy

Hydrogen, generated from water splitting, is postulated as one of the most promising alternatives to fossil fuels. In this context, direct hydrogen generation by electrolysis and fixation to graphene oxide in an aqueous suspension could overcome storage and distribution problems of gaseous hydrogen. This study presents time-resolved determination of the electrochemical hydrogenation of GO by in-situ Raman spectroscopy, simultaneous to original functional groups elimination. Hydrogenation is found favoured by dynamic modulation of the electrochemical environment compared to fixed applied potentials, with a 160% increase of C-H bond formation. Epoxide groups suppression and generated hydroxide groups point at these epoxide groups being one of the key sites where hydrogenation was possible. FTIR revealed characteristic symmetric and asymmetric stretching vibrations of C-H bonds in CH and CH groups. This shows that hydrogenation is significantly also occurring in defective sites and edges of the graphene basal plane, rather than H-Csp groups as graphane. We also determined a −0.05 V reduction starting potential in alkaline electrolytes and a 150 mV cathodic delay in acid electrolytes. The identified key parameters role, together with observed diverse C-H groups formation, points at future research directions for large-scale hydrogen storage in graphene