Association of radio polar cap brightening with bright patches and coronal holes

Radio-bright regions near the solar poles are frequently observed in Nobeyama Radioheliograph (NoRH) maps at 17 GHz, and often in association with coronal holes. However, the origin of these polar brightening has not been established yet. We propose that small magnetic loops are the source of these bright patches, and present modeling results that reproduce the main observational characteristics of the polar brightening within coronal holes at 17 GHz. The simulations were carried out by calculating the radio emission of the small loops, with several temperature and density profiles, within a 2D coronal hole atmospheric model. If located at high latitudes, the size of the simulated bright patches are much smaller than the beam size and they present the instrument beam size when observed. The larger bright patches can be generated by a great number of small magnetic loops unresolved by the NoRH beam. Loop models that reproduce bright patches contain denser and hotter plasma near the upper chromosphere and lower corona. On the other hand, loops with increased plasma density and temperature only in the corona do not contribute to the emission at 17 GHz. This could explain the absence of a one-to-one association between the 17 GHz bright patches and those observed in extreme ultraviolet. Moreover, the emission arising from small magnetic loops located close to the limb may merge with the usual limb brightening profile, increasing its brightness temperature and width.Comment: 8 pages, 6 figures, 1 table. Accepted for publication in The Astrophysical Journa

Microsite Drivers of Natural Seed Regeneration of Eucalyptus globulus Labill. in Burnt Plantations

Fire regimes are changing in several regions of the world. In those regions, some exotic species may be better adapted to new regimes than the native species. This study focused on identifying the microsite characteristics associated with the occurrence of post-fire Eucalyptus globulus regeneration from seeds, outside the species native-range. This information is important in helping to assess the naturalization status of the species, to understand its invasion risk, and to manage wildlings in plantations. To characterize the establishment niche, pairs of microsites (sapling presence/ absence) were sampled in four salvage-logged plantations of E. globulus two years after fire (20 pairs/plantation). Microsites of wildlings from three size classes and control microsites were established in one of these plantations (20 quartets) in order to characterize the recruitment niche and to assess ontogenic niche shifts. Two post-fire wildling cohorts were identified. The first emerged just after fire and was abundant. The second emerged after logging and was scarce, probably due to seed limitation. First-cohort wildlings were observed in microsites characterized by a high incidence of fire-related variables (charcoal, ash, increased soil pH and K). The aggregated distribution of these wildlings and their association with other species may indicate the existence of facilitative relationships and/or the exploitation of resource-rich patches. All these factors were relevant for first-cohort persistence and likely also for its establishment and recruitment. Second-cohort wildlings occurred in microsites where salvage-logging disturbance was evident, showing the importance of this disturbance for its emergence. Wildling size diversity was explained by the two recruitment events and by the asymmetrical competition between wildlings and adults. No niche shifts were detected. The high densities of E. globulus wildlings found established in burnt plantations indicated naturalization was in progress. The timing of major recruitment events and the phenology of the species should be considered for monitoring this regeneration and scheduling control interventions, if requiredinfo:eu-repo/semantics/publishedVersio

In vitro evaluation of the behaviour of human polymorphonuclear neutrophils in direct contact with chitosan-based membranes

Several novel biodegradable materials have been proposed for wound healing applications in the past few years. Taking into consideration the biocompatibility of chitosan-based biomaterials, and that they promote adequate cell adhesion, this work aims at investigating the effect of chitosanbased membranes, over the activation of human polymorphonuclear neutrophils (PMNs). The recruitment and activation of polymorphonuclear neutrophils (PMNs) reflects a primary reaction to foreign bodies. Activation of neutrophils results in the production of reactive oxygen species (ROS) such as O2 − and HO− and the release of hydrolytic enzymes which are determinant factors in the inflammatory process, playing an essential role in the healing mechanisms. PMNs isolated from human peripheral blood of healthy volunteers were cultured in the presence of chitosan or chitosan/soy newly developed membranes. The effect of the biomaterials on the activation of PMNs was assessed by the quantification of lysozyme and ROS. The results showed that PMNs, in the presence of the chitosan-based membranes secrete similar lysozyme amounts, as compared to controls (PMNs without materials) and also showed that the materials do not stimulate the production of either O2 − or HO−. Moreover, PMNs incubated with the biomaterials when stimulated with phorbol 12-myristate 13-acetate (PMA) or formyl-methionyl-leucyl-phenylalanine (fMLP) showed a chemiluminescence profile with a slightly lower intensity, to that observed for positive controls (cells without materials and stimulated with PMA), which reflects the maintenance of their stimulation capacity. Our data suggests that the new biomaterials studied herein do not elicit activation of PMNs, as assessed by the low lysozyme activity and by the minor detection of ROS by chemiluminescence. These findings reinforce previous statements supporting the suitability of chitosan-based materials for wound healing applications

Natural establishment of Eucalyptus globulus Labill. in burnt stands in Portugal

Exotic tree species are increasingly common in many regions of the world and at least some species are becoming naturalized in the regions where they were introduced. Disturbances like fire may be at the origin or accelerate the naturalization of these species. Portugal holds one of the largest areas of exotic Eucalyptus globulus plantations in the world and is one of the countries most affected by forest fires. These two facts have triggered the present research. This study aimed at characterising medium-term natural establishment of E. globulus plants originated from seeds under natural conditions in burnt planted forests (pure E. globulus stands, pure Pinus pinaster stands, and mixed stands of both species), and at analysing factors associated with this establishment. Occurrence, abundance and height of naturally established E. globulus plants were characterized in 284 sites distributed in burnt areas, across Central and Northern Portugal, 5– 7 years after wildfire. Generalized linear models were used to assess the influence of stand type, regional productivity potential, and post-fire management practices on occurrence probability, density, and median height of sampled E. globulus individuals. The influence of these explanatory variables on the structure (in terms of size class distribution) of naturally established E. globulus cohort was examined using analysis of similarity and non-metric multidimensional scaling. Naturally established E. globulus plants were present in 93.1%, 19.0% and 98.6% of samples in pure E. globulus, pure P. pinaster and mixed stands, respectively. Cohort median density was 0.20 plants m 2 and maximum density was 4.55 plants m 2. Median height of plantswas 2.0 mand 95.3% of them had h >1.30 mand DBH 65 cm. Establishment probability, density and median height were highest in the most productive regions. Three post-fire management operations had a significant influence on the response variables: (i) salvage logging was associated with a higher density; (ii) tillage was associated with a lower density and a smaller median height; (iii) understorey removal was associated with a lower occurrence probability. Tillage was the only studied factor influencing the size structure of spontaneously established cohort, eliminating larger plants. This study showed that stand type, productivity region and post-fire management operations might have significantly influenced the natural establishment of E. globulus in burnt areas, and consequently the species naturalization process in Portugal. The implications of these findings for management are discussedinfo:eu-repo/semantics/publishedVersio

A Review of Commercial and Medical-Grade Physiological Monitoring Devices for Biofeedback-Assisted Quality of Life Improvement Studies

With the rise in wearable technology and "health culture", we are seeing an increasing interest and affordances in studying how to not only prolong life expectancy but also in how to improve individuals' quality of life. On the one hand, this attempts to give meaning to the increasing life expectancy, as living above a certain threshold of pain and lack of autonomy or mobility is both degrading and unfair. On the other hand, it lowers the cost of continuous care, as individuals with high quality of life indexes tend to have lower hospital readmissions or secondary complications, not to mention higher physical and mental health. In this paper, we evaluate the current state of the art in physiological therapy (biofeedback) along with the existing medical grade and consumer grade hardware for physiological research. We provide a quick primer on the most commonly monitored physiologic metrics, as well as a brief discussion on the current state of the art in biofeedback-assisted medical applications. We then go on to present a comparative analysis between medical and consumer grade biofeedback devices and discuss the hardware specifications and potential practical applications of each consumer grade device in terms of functionality and adaptability for controlled (laboratory) and uncontrolled (field) studies. We end this article with some empirical observations based on our study so that readers might use take them into consideration when arranging a laboratory or real-world experience, thus avoiding costly time delays and material expenditures.info:eu-repo/semantics/publishedVersio

The insertion of the transnational capital and the expropriation of local natural resources: an analysis of agribusiness in the southwest of Piauí

The current movement of land acquisition by transnational capital in so-called developing countries is a subject that is gaining the attention of the scientific community, especially after the convergence of the economic crisis of 2007/2008. In this context, from bibliographical revision and documentary survey, we discuss the land appropriation by agribusiness, taking as axiomatic examples Brazil and, in particular, the southwest of Piauí. Considering the current expansion of the agricultural frontier, characterized by land concentration and the control of local natural resources, we highlight the apparent advance of such movement towards the Brazilian semiarid region, with the increase of the number and area of agricultural establishments in zones near to the transition of the biomes Cerrado and Caatinga