Improving Optical Flow Sensor Using a Gimbal for Quadrotor Navigation in GPS-Denied Environment.

This paper proposes a new sensor using optical flow to stabilize a quadrotor when a GPS signal is not available. Normally, optical flow varies with the attitude of the aerial vehicle. This produces positive feedback on the attitude control that destabilizes the orientation of the vehicle. To avoid this, we propose a novel sensor using an optical flow camera with a 6DoF IMU (Inertial Measurement Unit) mounted on a two-axis anti-shake stabilizer mobile aerial gimbal. We also propose a robust algorithm based on Sliding Mode Control for stabilizing the optical flow sensor downwards independently of the aerial vehicle attitude. This method improves the estimation of the position and velocity of the quadrotor. We present experimental results to show the performance of the proposed sensor and algorithms.

Physically and Chemically Cross-Linked Poly(vinyl alcohol)/Humic Acid Hydrogels for Agricultural Applications.

The preparation method of hydrogels has a significant effect on their structural and physicochemical properties. In this report, physically and chemically cross-linked poly(vinyl alcohol) (PVA) networks containing humic acid (HA) were alternatively prepared by autoclaving (AC) and through glutaraldehyde (GA) addition, respectively, for agricultural purposes. PVA/HA hydrogels were comparatively characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, mechanical assays, scanning electron microscopy, swelling kinetics measurements, and water retention tests in soil. AC hydrogels showed a more homogeneous porous microstructure, higher swelling levels, and a better capacity to preserve the humidity of soil than those obtained by adding GA. Both PVA/HA hydrogels exhibited no phytotoxicity on cultivation trials of Sorghum sp., but the plant growth was promoted with the GA-cross-linked network as compared to the effect of the AC sample. The release behavior of urea was modified according to the preparation method of the PVA/HA hydrogels. After 3 days of sustained urea release, 91% of the fertilizer was delivered from the AC hydrogel, whereas a lower amount of 56% was released for the GA-cross-linked hydrogel. Beyond the advantages of applying PVA/HA hydrogels in the agricultural field, an appropriate method of preparing these materials endows them with specific properties according to the requirements of the target crop.

Real-Time Person Detection in Wooded Areas Using Thermal Images from an Aerial Perspective.

Detecting people in images and videos captured from an aerial platform in wooded areas for search and rescue operations is a current problem. Detection is difficult due to the relatively small dimensions of the person captured by the sensor in relation to the environment. The environment can generate occlusion, complicating the timely detection of people. There are currently numerous RGB image datasets available that are used for person detection tasks in urban and wooded areas and consider the general characteristics of a person, like size, shape, and height, without considering the occlusion of the object of interest. The present research work focuses on developing a thermal image dataset, which considers the occlusion situation to develop CNN convolutional deep learning models to perform detection tasks in real-time from an aerial perspective using altitude control in a quadcopter prototype. Extended models are proposed considering the occlusion of the person, in conjunction with a thermal sensor, which allows for highlighting the desired characteristics of the occluded person.

Unravelling the skills and motivations of Magdalenian artists in the depths of Atxurra Cave (Northern Spain).

Atxurra cave has a decorated assemblage composed of more than a hundred engraved animal depictions. All of them are located in deep parts of the cave and most of them are hidden in raised areas, away from the main path. The main sector is the "Ledge of the Horses", located at 330 m from the entrance of the cave. It is a space of 12 m long and 1.5 m wide, elevated 4 m above the cave floor. This area includes almost fifty engraved and painted animals accompanied by a dozen flint tools, three fireplaces, and around one hundred charcoal fragments from torches. This extraordinary archaeological record allows us to value the complexity of the artistic production inside the caves during the Upper Palaeolithic. Our study has confirmed that there is planning prior to artistic production, both in terms of the iconographic aspects (themes, techniques, formats), its location (visibility, capacity), and the lighting systems. Furthermore, the data indicates the panel was decorated to be seen by third parties from different positions and was expressly illuminated for this purpose. This evidence supports the role of rock art as a visual communication system in Upper Palaeolithic societies.

Neurogenic diabetes insipidus in a critical patient with COVID-19 pneumonia in treatment with extracorporeal membrane oxygenation: a case report.

The following case report analyses a patient with extracorporeal membrane oxygenation (ECMO), who suffered from a severe Acute Respiratory Distress Syndrome (ARDS) due to COVID-19 pneumonia. ARDS is defined as a diffuse and inflammatory injury of the lungs; classifying this as severe when the ratio of arterial oxygen tension to a fraction of inspired oxygen (PaO2/FiO2) is equal to or lower than 100 mmHg. To decide if the patient was suitable for the use of ECMO therapy, the ELSO criteria were used; and in this case, the patient matched with the criteria of hypoxemic respiratory failure (with a PaO2/FiO2 < 80 mmHg) after optimal medical management, including, in the absence of contraindications, a trial of prone positioning. During hospitalization, the patient presented a Central Diabetes Insipidus (CDI), probably explained by the damage hypoxia generated on the central nervous system. There are few reports of this complication produced by COVID-19. The case is about a 39-year-old woman, who started with ECMO 6 days after the beginning of Invasive Mechanical Ventilation (IMV), because of a severe ARDS. On the fifth day of ECMO, the patient started with a polyuria of 7 L in 24 h. A series of paraclinical studies were made, but no evidence of central nervous system lesions was found. After treatment with desmopressin was initiated and the ARDS was solved, polyuria stopped; with this, CDI was diagnosed. There are many complications secondary to the evolution of COVID-19 infection, and some of them are not yet well explained.

Lower Limb Exoskeleton for Rehabilitation with Flexible Joints and Movement Routines Commanded by Electromyography and Baropodometry Sensors.

This paper presents the development of an instrumented exoskeleton with baropodometry, electromyography, and torque sensors. The six degrees of freedom (Dof) exoskeleton has a human intention detection system based on a classifier of electromyographic signals coming from four sensors placed in the muscles of the lower extremity together with baropodometric signals from four resistive load sensors placed at the front and rear parts of both feet. In addition, the exoskeleton is instrumented with four flexible actuators coupled with torque sensors. The main objective of the paper was the development of a lower limb therapy exoskeleton, articulated at hip and knees to allow the performance of three types of motion depending on the detected user's intention: sitting to standing, standing to sitting, and standing to walking. In addition, the paper presents the development of a dynamical model and the implementation of a feedback control in the exoskeleton.

Porous Structural Properties of K or Na-Co Hexacyanoferrates as Efficient Materials for CO2 Capture.

The stoichiometry of the components of hexacyanoferrate materials affecting their final porosity properties and applications in CO2 capture is an issue that is rarely studied. In this work, the effect that stoichiometry of all element components and oxidation states of transition metals has on the structures of mesoporous K or Na-cobalt hexacyanoferrates (CoHCFs) and CO2 removal is reported. A series of CoHCFs model systems are synthesized using the co-precipitation method with varying amounts of Co ions. CoHCFs are characterized by N2 adsorption, TGA, FTIR-ATR, XRD, and XPS. N2 adsorption results reveal a more developed external surface area (72.69-172.18 m2/g) generated in samples containing mixtures of K+/Fe2+/Fe3+ ions (system III) compared to samples with Na+/Fe2+ ions (systems I, II). TGA results show that the porous structure of CoHCFs is affected by Fe and Co ions oxidation states, the number of water molecules, and alkali ions. The formation of two crystalline cells (FCC and triclinic) is confirmed by XRD results. Fe and Co oxidation states are authenticated by XPS and allow for the confirmation of charges involved in the stabilization of CoCHFs. CO2 removal capacities (3.04 mmol/g) are comparable with other materials reported. CO2 adsorption kinetics is fast (3-6 s), making CoHCFs attractive for continuous operations. Qst (24.3 kJ/mol) reveals a physical adsorption process. Regeneration effectiveness for adsorption/desorption cycles indicates ~1.6% loss and selectivity (~47) for gas mixtures (CO2:N2 = 15:85). The results of this study demonstrate that the CoHCFs have practical implications in the potential use of CO2 capture and flue gas separations.

Allowing access to parents/caregivers into COVID-19 hospitalization areas does not increase infections among health personnel in a pediatric hospital.

Background: At the beginning of the current COVID-19 pandemic, it became critical to isolate all infected patients, regardless of their age. Isolating children has a negative effect on both, them and their parents/caregivers. Nevertheless isolation was mandatory because of the potential risk that visitation might have on COVID-19 dissemination mostly among health personnel. Methods: From the starting of the COVID-19 pandemic in our pediatric hospital visits were forbidden. This 2 months period (April-May) was called P1. In June parents were allowed to visit (P2), under a visiting protocol previously published. Hospital workers were monitored for the presence of COVID-19 symptoms and tested for the infection when clinically justified. The positivity proportion and the relative risk (RR) of COVID-19 among the health personnel between periods were calculated. The caregivers were also followed up by phone calls. Results: Since April 2020 to November 2020, 2,884 health personnel were studied for 234 days, (318,146 workers days). Although the COVID-19/1,000 health personnel days rate decreased from one period to another (1.43 vs 1.23), no statistically significant differences were found. During P1, 16 patients with COVID-19 were treated. During the follow up none of the family members were infected/symptomatic in P1, while in P2, 6/129 (4.65%) were symptomatic or had a positive test. All of them initiated between 2 and 4 days after the patient's admission. As they also had some other infected family members it was not possible to ensure the source of infection. There were no statistically significant differences in the RR of COVID-19 in health personnel, (RR 1, 95% CI 0.69-1.06, p = 0.162). Conclusions: When safely implemented, allowing parents/caregivers to spend time with their hospitalized COVID-19 children does not increase the contagion risk for hospital workers or among themselves.

Phenotypic Variability and Genetic Diversity of the Pathogenic Fungus Macrophomina phaseolina from Several Hosts and Host Specialization in Strawberry.

Macrophomina phaseolina, is a pathogenic soil-borne fungus that affects more than 500 plant species, causing various types of disease to several crops, among which is the crown and root rot disease in strawberry. Its wide variability has been characterized reiteratively in the literature, but little is known about its virulence mechanisms. Morphological, physiological, genetic and phytopathogenic parameters were evaluated among 32 isolates of Macrophomina from different hosts occurring in Argentina and Spain. Colony characteristics, average size of microsclerotia, chlorate phenotype and mycelial growth at different temperatures (5º-40 °C), and pH (3.0-8.0) were recorded. The morphological and physiological traits were heterogeneous and did not show any association with the genetic structure nor with their pathogenicity. Most of the isolates (71.9%) exhibited chlorate-sensitive phenotype. The optimal growth temperature range was between 25 °C and 35 °C, and the optimal pH varied between 4.0 and 6.0. The genetic structure analyzed with four DNA markers (EF-1α, ITS, CAL and TUB) showed little diversity among isolates of M. phaseolina, with no clear association with the country of origin, but a significant association with the host. Based on their phylogenetic affinity, one isolate was reclassified as M. pseudophaseolina and another one as M. tecta. It is the first report of M. pseudophaseolina causing charcoal rot on beans, in Argentina, and the first report of M. tecta outside Australia. Pathogenicity tests on strawberry plants revealed marked host specialization, being the isolates obtained from strawberry more virulent than those from other hosts.

A fungal protease named AsES triggers antiviral immune responses and effectively restricts virus infection in arabidopsis and Nicotiana benthamiana plants.

BACKGROUND AND AIMS: Plants have evolved complex mechanisms to fight against pathogens. Among these mechanisms, pattern-triggered immunity (PTI) relies on the recognition of conserved microbe- or pathogen-associated molecular patterns (MAMPs or PAMPs, respectively) by membrane-bound receptors. Indeed, PTI restricts virus infection in plants and, in addition, BRI1-associated kinase 1 (BAK1), a central regulator of PTI, plays a role in antiviral resistance. However, the compounds that trigger antiviral defences, along with their molecular mechanisms of action, remain mostly elusive. Herein, we explore the role of a fungal extracellular subtilase named AsES in its capacity to trigger antiviral responses. METHODS: In this study, we obtained AsES by recombinant expression, and evaluated and characterized its capacity to trigger antiviral responses against Tobacco mosaic virus (TMV) by performing time course experiments, analysing gene expression, virus movement and callose deposition. KEY RESULTS: The results of this study provide direct evidence that exogenous treatment with recombinant AsES increases a state of resistance against TMV infection, in both arabidopsis and Nicotiana benthamiana plants. Also, the antiviral PTI response exhibited by AsES in arabidopsis is mediated by the BAK1/SERK3 and BKK1/SERK4 co-receptors. Moreover, AsES requires a fully active salicylic acid (SA) signalling pathway to restrict the TMV movement by inducing callose deposition. Additionally, treatment with PSP1, a biostimulant based on AsES as the active compound, showed an increased resistance against TMV in N. benthamiana and tobacco plants. CONCLUSIONS: AsES is a fungal serine protease which triggers antiviral responses relying on a conserved mechanism by means of the SA signalling pathway and could be exploited as an effective and sustainable biotechnology strategy for viral disease management in plants.

Energetic optimization of an autonomous mobile socially assistive robot for autism spectrum disorder.

The usage of socially assistive robots for autism therapies has increased in recent years. This novel therapeutic tool allows the specialist to keep track of the improvement in socially assistive tasks for autistic children, who hypothetically prefer object-based over human interactions. These kinds of tools also allow the collection of new information to early diagnose neurodevelopment disabilities. This work presents the integration of an output feedback adaptive controller for trajectory tracking and energetic autonomy of a mobile socially assistive robot for autism spectrum disorder under an event-driven control scheme. The proposed implementation integrates facial expression and emotion recognition algorithms to detect the emotions and identities of users (providing robustness to the algorithm since it automatically generates the missing input parameters, which allows it to complete the recognition) to detonate a set of adequate trajectories. The algorithmic implementation for the proposed socially assistive robot is presented and implemented in the Linux-based Robot Operating System. It is considered that the optimization of energetic consumption of the proposal is the main contribution of this work, as it will allow therapists to extend and adapt sessions with autistic children. The experiment that validates the energetic optimization of the proposed integration of an event-driven control scheme is presented.

Dietary Insights in Neurological Diseases.

PURPOSE OF REVIEW: Dietary interventions may play a role in the pathophysiology of common neurological disorders such as Alzheimer's disease, Parkinson's disease, stroke, migraines, multiple sclerosis, and epilepsy. This article describes the most common and impactful dietary regimens for commonly encountered neurological disorders. RECENT FINDINGS: Plant-based, low-fat, high-fiber diets, rich in antioxidants and other lifestyle interventions may reduce the burden and disability of common neurological disorders. The ketogenic diet, the diet of choice for the treatment of refractory epilepsy, is such an example. Diverse neurological disorders demonstrate several common pathophysiological mechanisms including increased oxidative stress, neuroinflammation, and disrupted metabolism. Dietary interventions can potentially influence these pathophysiological processes and thus favorably alter clinical outcomes. Adequate dietary choices should be considered as part of a continuum of healthy lifestyle choices.

Chemical speciation of selected toxic metals and multivariate statistical techniques used to assess water quality of tropical Mexican Lake Chapala.

Mexican Lake Chapala is used as water supply for human consumption. Consequently, water quality of this lake is of paramount importance for the lake's wellbeing. The contribution presented in this paper investigates monitoring and assessment of lake water quality using water quality index (WQI), metal chemical speciation, and multivariate statistical techniques. Descriptive statistics shows total metal concentrations undetected conferring the lake a healthy status. Dissolved Cd and Pb exceed criterion continuous concentration limit, whereas Zn is below this limit indicating that water quality is satisfactory for aquatic life. However, WQI indicates poor water quality attributed to failure of conductivity, total solids, nitrogen, and phosphates, due to industrial and agro-industrial effluents. Metal speciations indicate that the presence of low concentrations of dissolved metals reflect interactions with gills of fish through metal-biotic ligand complexes affecting water quality. Positive correlations are obtained between conductivity and nitrates, indicating that agricultural activities and fertilizer runoffs increase the conductivity and that the environmental state of lake is being altered by human activities. Factors F1 (31%), F2 (19%), and F3 (11%) represent 61% of variability; F1 and F2 corroborate the pressure exerted by pollutants related with fertilizers and agrochemicals; F3 contains Zn and Pb with positive loads attributed to influx of tourist visitors. Sites S4, S5, S6, and S9 are identified as the most environmentally affected by COD, Alk*, pH, Cl-, nitrites, phosphates, and TS. Multivariate techniques permit to conclude that environmental stress of Lake Chapala is caused by variables pertaining to agrochemical, fertilizers and municipal wastes.

Natural occurrence of Azospirillum brasilense in petunia with capacity to improve plant growth and flowering.

To evaluate the natural occurrence of the plant growth-promoting bacterium Azospirillum brasilense and petunia plants, local strains were isolated and characterized by biochemical and molecular methods. Three strains were assessed in greenhouse conditions using Petunia × hybrida Ultra™. Treatments: Plants without bacterial inoculation or chemical fertilization; fertilized with NPK and KNO3 ; and independently inoculated with the strains 2A1, 2A2, and 2E1 by submerging their roots in a bacterial suspension (~106 CFU·ml-1 ). Root length, dry weight of roots and shoots, leaf area, leaf greenness, and nutrient content were evaluated. The number of days from transplanting to the opening of the first flower and the number of flowers per plant were also determined. As a result, five isolates were characterized as A. brasilense, showing the capacity to produce indoles and siderophores, to solubilize phosphate, nitrogenase activity, and nifH-PCR amplification. In general, all the parameters of the plant assay were improved in plants inoculated with A. brasilense, with variations among the strains, as well as the onset of flowering and the number of flowers per plant, compared with uninoculated or fertilized plants. This is the first report on the natural occurrence of A. brasilense in petunia with the capacity to improve plant growth and flowering.

Redefining shared symbolic networks during the Gravettian in Western Europe: New data from the rock art findings in Aitzbitarte caves (Northern Spain).

The renewal of the archaeological record, mainly through the discovery of unpublished sites, provides information that sometimes qualifies or even reformulates previous approaches. One of the latter cases is represented by the three new decorated caves found in 2015 in Aitzbitarte Hill. Their exhaustive study shows the presence of engraved animals, mainly bison, with formal characteristics unknown so far in the Palaeolithic art of the northern Iberian Peninsula. However, parallels are located in caves in southern France such as Gargas, Cussac, Roucadour or Cosquer. All of them share very specific graphic conventions that correspond to human occupations assigned basically to the Gravettian cultural complex. The new discovery implies the need to reformulate the iconographic exchange networks currently accepted, as well as their correspondence with other elements of the material culture at the same sites. Thus, we have carried out a multiproxy approach based in statistical analysis. The updated data reveals a greater complexity in artistic expression during the Gravettian that had not been considered so far, and also challenges the traditional isolation that had been granted to Cantabrian symbolic expressions during pre-Magdalenian times.

Adaptive tracking control of an unmanned aerial system based on a dynamic neural-fuzzy disturbance estimator.

The main goal of this study is developing an adaptive controller which can solve the trajectory tracking for a class of quadcopter unmanned aerial system (UAS), namely a quadrotor. The control design introduces a new paradigm for adaptive controllers based on the implementation of a set of differential neural networks (DNNs) in the consequence section of a Takagi-Sugeno (T-S) fuzzy inference system. This dynamic fuzzy inference structure was used to approximate the UAS description. The particular form of interaction between neural networks and fuzzy inference systems proposed in the present work received the name of dynamic neural fuzzy system (DNFS). An adaptive controller based on this DNFS form was the main solution attained in this study. This DNFS controller was focused on the estimation and compensation of the uncertain section of the Quadrotor dynamics and then, forced the UAS to perform a hover flight while the tracking of desired angular positions succeeded, which results in tracking a desired trajectory in the X-Y plane. The control design methodology supported on the Lyapunov stability theory guaranteed ultimate boundedness of the estimation and tracking errors simultaneously. Several experimental tests in an outdoor environment by using a real Quadrotor platform was performed by using an RTK-GPS (Real Time Kinematic) system to determine the position of the vehicle in the X-Y plane. The experimental results confirmed the superior performance of the proposed algorithm based on the combination of DNNs and T-S techniques with respect to classical robust controllers.

Expanding the Regulon of the Bradyrhizobium diazoefficiens NnrR Transcription Factor: New Insights Into the Denitrification Pathway.

Denitrification in the soybean endosymbiont Bradyrhizobium diazoefficiens is controlled by a complex regulatory network composed of two hierarchical cascades, FixLJ-FixK2-NnrR and RegSR-NifA. In the former cascade, the CRP/FNR-type transcription factors FixK2 and NnrR exert disparate control on expression of core denitrifying systems encoded by napEDABC, nirK, norCBQD, and nosRZDFYLX genes in response to microoxia and nitrogen oxides, respectively. To identify additional genes controlled by NnrR and involved in the denitrification process in B. diazoefficiens, we compared the transcriptional profile of an nnrR mutant with that of the wild type, both grown under anoxic denitrifying conditions. This approach revealed more than 170 genes were simultaneously induced in the wild type and under the positive control of NnrR. Among them, we found the cycA gene which codes for the c 550 soluble cytochrome (CycA), previously identified as an intermediate electron donor between the bc 1 complex and the denitrifying nitrite reductase NirK. Here, we demonstrated that CycA is also required for nitrous oxide reductase activity. However, mutation in cycA neither affected nosZ gene expression nor NosZ protein steady-state levels. Furthermore, cycA, nnrR and its proximal divergently oriented nnrS gene, are direct targets for FixK2 as determined by in vitro transcription activation assays. The dependence of cycA expression on FixK2 and NnrR in anoxic denitrifying conditions was validated at transcriptional level, determined by quantitative reverse transcription PCR, and at the level of protein by performing heme c-staining of soluble cytochromes. Thus, this study expands the regulon of NnrR and demonstrates the role of CycA in the activity of the nitrous oxide reductase, the key enzyme for nitrous oxide mitigation.