We investigate the synchronization features of a network of spiking neurons under a distance-dependent coupling following a power-law model. The interplay between topology and coupling strength leads ...to the existence of different spatiotemporal patterns, corresponding to either non-synchronized or phase-synchronized states. Particularly interesting is what we call synchronization malleability, in which the system depicts significantly different phase synchronization degrees for the same parameters as a consequence of a different ordering of neural inputs. We analyze the functional connectivity of the network by calculating the mutual information between neuronal spike trains, allowing us to characterize the structures of synchronization in the network. We show that these structures are dependent on the ordering of the inputs for the parameter regions where the network presents synchronization malleability and we suggest that this is due to a complex interplay between coupling, connection architecture, and individual neural inputs.
On September 26, 2022, NASA's Double Asteroid Redirection Test (DART) mission successfully impacted Dimorphos, the natural satellite of the binary near-Earth asteroid (65803) Didymos. Numerical ...simulations of the impact provide a means to explore target surface material properties and structures, consistent with the observed momentum deflection efficiency, ejecta cone geometry, and ejected mass. Our simulation, which best matches observations, indicates that Dimorphos is weak, with a cohesive strength of less than a few pascals (Pa), similar to asteroids (162173) Ryugu and (101955) Bennu. We find that a bulk density of Dimorphos, rhoB, lower than 2400 kg/m3, and a low volume fraction of boulders (<40 vol%) on the surface and in the shallow subsurface, are consistent with measured data from the DART experiment. These findings suggest Dimorphos is a rubble pile that might have formed through rotational mass shedding and re-accumulation from Didymos. Our simulations indicate that the DART impact caused global deformation and resurfacing of Dimorphos. ESA's upcoming Hera mission may find a re-shaped asteroid, rather than a well-defined crater.
Turning chips of zirconium alloys are produced in large quantities during the machining of alloy rods for the fabrication of the end plugs for the Pressurized Water Reactor (PWR) fuel elements parts ...of Angra II nuclear reactor (Brazil – Rio de Janeiro). This paper presents a study on the search for an efficient way for the cleaning, quality control and Vacuum Arc Remelting (VAR) of pressed zirconium alloys chips to produce a material viable to be used in the production of the fuel rod end plugs. The process starts with cutting oil clean out. The first step in this process consists in soaking a bunch of chips in clean water, to remove soluble cutting oils, followed by an alkaline degreasing bath and a wash with a high-pressure flow of water. Drying is performed by a flux of warm air. The oil free chips are then subjected to a magnet in order to detect and collect any magnetic material, essentially ferrous, that may be present in the original chips. Samples of the material are collected and then melted in a small non consumable electrode vacuum arc furnace for evaluation by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRFS) in order to define the quality of the chips. The next step consists in the 15 ton hydraulic pressing the chips in a die with 40 mm square section and 500 mm long, producing an electrode with 20% of the Zircaloy bulk density. The electrode was finally melted in a laboratory scale modified VAR furnace located at the CCTM–IPEN, producing 0.8 kg ingots. The authors conclude that the samples obtained from the fuel element industry can be melting in a VAR furnace, modified to accommodate low density electrodes, allowing a reduction up to 40 times the original storage volume, however, it is necessary to remelt the ingots to correct their composition in order to recycle the original zirconium alloys chips.
in a process to reduce volume and allow the reutilization of valuable Zircaloy scraps.
An improved method is described for the quantitation of lidocaine and its dominant metabolites in rat plasma, 3-hydroxy-lidocaine glucuronide and 3-hydroxy-MEG-X glucuronide. Frozen plasma samples ...(100-200 microliters) were thawed and deproteinated by precipitation with acetonitrile, before the conversion of glucuronidates into their respective hydroxylated forms by acid hydrolysis. After extraction with solid-phase C18 cartridge chromatography, the metabolites and parent drug were analyzed by capillary gas chromatography-nitrogen phosphorus detection, without derivativization. A detection limit of 0.005 microgram/ml for lidocaine and nonglucuronidated metabolites and 0.01 microgram/ml for glucuronidated metabolites was achieved. The method offers significant improvements in sensitivity relative to existing techniques, which should be of specific benefit to studies in which sample volume is limited, such as those concerned with the pharmacokinetics of lidocaine metabolism in small-animal pain state models.
The objective of this study was to verify the effects of ethanol consumption and alcohol detoxification on the biomechanics, area and thickness of cortical and trabecular bone in rat femur. This was ...an experimental study in which 18 male Wistar rats were used, with 40 days of age, weighing 179 ± 2.5 g. The rats were divided into three groups (n=06): CT (control), AC (chronic alcoholic), DT (detoxification). After experimental procedures, the animals were euthanized by an overdose of the anesthetic and their femurs were collected for mechanical testing and histological processing. All animals did not present malnutrition or dehydration during experimentation period. Morphometric analysis of cortical and trabecular bones in rat femurs demonstrated that AC animals showed inferior dimensions and alcohol detoxification (DT) allowed an enhancement in area and thickness of cortical and trabecular bone. Material and structural properties data of AC group highlighted the harmful effects of ethanol on bone mechanical properties. The results of this study demonstrated that chronic alcoholic rats (AC) presented major bone damage in all analyzed variables. Those findings suggested that alcohol detoxification is highly suggested in pre-operative planning and this corroborates to the success of bone surgery and bone tissue repair. Thanks to the financial support offered by PROBIC--UNIFENAS. Keywords: ethanol, rats, bone, alcoholism, detoxification. O objetivo deste estudo foi verificar os efeitos do consumo de etanol e da desintoxicacao alcoolica sobre a biomecanica, area e espessura do osso cortical e trabecular em femur de ratos. Este foi um estudo experimental no qual foram utilizados 18 ratos Wistar machos, com 40 dias de vida, pesando 179 ± 2,5 g. Os ratos foram divididos em tres grupos (n=06): CT (controle), AC (alcoolista cronico), e DT (desintoxicado). Apos os procedimentos experimentais os animais foram eutanaziados por uma overdose de anestesico e os femures coletados para os testes mecanicos e processamento histologico. Todos os animais nao apresentaram desnutricao ou desidratacao durante o periodo de experimentacao. As analises morfometrica do osso cortical e trabecular demonstraram que os animais do grupo AC apresentavam dimensoes inferiores, enquanto nos animais do grupo DT observou-se um aumento na area e espessura do osso cortical e trabecular. Dados dos materiais e das propriedades estruturais ossea do grupo AC destacam os efeitos nocivos do etanol sobre as propriedades mecanicas do osso. Os resultados deste estudo demonstraram que os ratos do grupo AC apresentaram danos significativos no osso em todas as variaveis analisadas. Esses resultados sugerem que a desintoxicacao alcoolica e recomendada no planejamento pre-operatorio e isso corrobora para o sucesso de cirurgias e reparacao no tecido osseo. Agradecemos ao apoio financeiro oferecido pelo PROBIC--UNIFENAS. Palavras-chave: etanol, ratos, osso, alcoolismo, desintoxicacao.
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•Changes in the Brazilian semi-arid coast reveal key questions to advance research.•Changes in the semi-arid coast can have consequences in the ecological stability and ...connectivity.•Modifications of the coastal dynamics can impact structure and function of adjacent marine ecosystems.•Semi-arid coast community dynamics under ongoing climate change should be monitored.•Beaches and nearshore mangroves erosion contrast with mangrove expansion inland.
Understanding the impacts on the Brazilian semi-arid coast, which is a drought-prone area (>1000 km) in the tropical Atlantic, and how ecosystems survive and adapt to such extreme environments requires socioecological studies to create a theory for conservation. Here, we highlight five main ongoing changes in tropical semi-arid areas, namely (1) the decrease in rainfall rates due to climate change, which alters freshwater flows, alters water residence times, and promotes hypersalinity (>37) in low-inflow estuaries; (2) sea-level rise, groundwater hazards, increased erosion of beaches and nearshore mangroves, and landward mangrove forest expansion due to enhanced saline intrusion along river basins; (3) the decrease in land-ocean fluxes due to silting and closure of sandy bars in estuarine mouths; (4) warming and increased intensity and frequency of extreme events (e.g., heat waves, droughts, and sea swells); and (5) growing eutrophication and hypoxia, loss of vegetation cover and biodiversity due to urbanization, aquaculture (shrimp farming), agriculture, and land-use change, which includes building dams for water supply. The alteration of biogeochemical processes (“Arctic Paradox” hypothesis) and acidification that potentialize the impact of contaminants and nutrients is also highlighted. These impacts have effects on food and water security and multiple trophic levels, which should preferentially be studied through a long-term approach for advancing research. Based on these concerns, we propose key questions that should guide research in the context of the Decade of Ocean Science for Sustainable Development (2021–2030) to support science-based management actions in Brazil and other similar semi-arid areas worldwide.
The murine model of ovalbumin (OVA)-induced allergy was used to evaluate the effectiveness of oral treatment with the leaf extract of
Cissampelos sympodialis Eichl. (Menispermaceae) (CS) in the ...modulation of immunoglobulin E (IgE) production and T cell activation. CS treatment with doses ranging from 200 to 600
mg/Kg/day for 15 days before and during OVA-sensitization promoted reduction in total and OVA-specific serum IgE. CS at 400 or 600
mg/Kg/day also reduced paw edema induced by local OVA challenge. Daily intake of up to 600
mg/Kg of oral CS by BALB/c mice did not reduce weight gain, which is indicative of a lack of systemic toxicity. To assess the effect of CS treatment on T cell proliferative response to stimuli in vitro, the mitogenic response of spleen cells of treated and control animals were evaluated. Cells from CS-treated animals showed an elevated background proliferative response to concanavalin-A (Con-A) when compared to those from control animals. Oral intake of CS increased the in vitro production of IFN-γ and IL-10 by Con-A stimulated cells. Mice treated with 200
mg/Kg/day CS showed increasing levels of IFN-γ. These results show that oral treatment with
Cissampelos sympodialis extract has an immunomodulatory effect, reducing allergy-associated responses possibly by a preferential activation of Th1-type cytokines.
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