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Electroencephalography (EEG) functional connectivity (FC) estimates are confounded by the volume conduction problem. This effect can be greatly reduced by applying FC measures insensitive to instantaneous, zero-lag dependencies (corrected measures). However, numerous studies showed that FC measures sensitive to volume conduction (uncorrected measures) exhibit higher reliability and higher subject-level identifiability. We tested how source reconstruction contributed to the reliability difference of EEG FC measures on a large (n = 201) resting-state data set testing eight FC measures (including corrected and uncorrected measures). We showed that the high reliability of uncorrected FC measures in resting state partly stems from source reconstruction: idiosyncratic noise patterns define a baseline resting-state functional network that explains a significant portion of the reliability of uncorrected FC measures. This effect remained valid for template head model-based, as well as individual head model-based source reconstruction. Based on our findings we made suggestions how to best use spatial leakage corrected and uncorrected FC measures depending on the main goals of the study.
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Conectoma , Eletroencefalografia , Rede Nervosa , Humanos , Eletroencefalografia/métodos , Eletroencefalografia/normas , Adulto , Conectoma/normas , Conectoma/métodos , Feminino , Masculino , Reprodutibilidade dos Testes , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Adulto Jovem , Imageamento por Ressonância Magnética/normas , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologiaRESUMO
The seemingly effortless ability of our auditory system to rapidly detect new events in a dynamic environment is crucial for survival. Whether the underlying brain processes are innate is unknown. To answer this question, electroencephalography was recorded while regularly patterned (REG) versus random (RAND) tone sequences were presented to sleeping neonates. Regular relative to random sequences elicited differential neural responses after only a single repetition of the pattern indicating the existence of an innate capacity of the auditory system to detect auditory sequential regularities. We show that the newborn auditory system accumulates evidence only somewhat longer than the minimum amount determined by the ideal Bayesian observer model (the prediction from a variable-order Markov chain model) before detecting a repeating pattern. Thus, newborns can quickly form representations for regular features of the sound input, preparing the way for learning the contingencies of the environment.
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Percepção Auditiva , Potenciais Evocados Auditivos , Humanos , Recém-Nascido , Estimulação Acústica , Potenciais Evocados Auditivos/fisiologia , Percepção Auditiva/fisiologia , Teorema de Bayes , Encéfalo/fisiologia , EletroencefalografiaRESUMO
Although atypical theta and alpha activity may be biomarkers of attention-deficit/hyperactivity disorder (ADHD) outcomes such as atypical affective processing and attention, the exact nature of the relations of these characteristics is unknown. We examined in age- and sex-matched adolescents (N = 132; Mage = 14.944, years, SD = .802) with and without ADHD, whether resting state (RS) theta and alpha power or theta and alpha event-related synchronization (ERS) during affect regulation (1) differ between adolescents with and without ADHD; (2) are differentially associated with event-related potential (ERP) and parent- and self-report measures of affective processing and inattention, given ADHD status and sex, and (3) are differentially lateralized, given ADHD status and sex. Adolescents with ADHD exhibited lower RS frontal-midline alpha power than adolescents without ADHD. In adolescents with ADHD, right parietal theta ERS was positively associated with the ERP measure of elaborate affective/motivational processing and right parietal RS alpha power was negatively associated with self-reported positive affectivity. In adolescents without ADHD, associations were nonsignificant. There was no disassociation of theta and alpha activity with affective processing and inattention. Consistent with clinical impressions, the between-group difference in frontal-midline theta ERS was more marked in boys than girls.
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Opioids are widely used for the pain management of acute pancreatitis (AP), but their impact on disease progression is unclear. Therefore, our aim was to study the effects of clinically relevant opioids on the severity of experimental AP. Various doses of fentanyl, morphine, or buprenorphine were administered as pre- and/or post-treatments in rats. Necrotizing AP was induced by the intraperitoneal injection of L-ornithine-HCl or intra-ductal injection of Na-taurocholate, while intraperitoneal caerulein administration caused edematous AP. Disease severity was determined by laboratory and histological measurements. Mu opioid receptor (MOR) expression and function was assessed in control and AP animals. MOR was expressed in both the pancreas and brain. The pancreatic expression and function of MOR were reduced in AP. Fentanyl post-treatment reduced necrotizing AP severity, whereas pre-treatment exacerbated it. Fentanyl did not affect the outcome of edematous AP. Morphine decreased vacuolization in edematous AP, while buprenorphine pre-treatment increased pancreatic edema during AP. The overall effects of morphine on disease severity were negligible. In conclusion, the type, dosing, administration route, and timing of opioid treatment can influence the effects of opioids on AP severity. Fentanyl post-treatment proved to be beneficial in AP. Clinical studies are needed to determine which opioids are best in AP.
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Buprenorfina/farmacologia , Fentanila/farmacologia , Morfina/farmacologia , Pancreatite Necrosante Aguda/patologia , Receptores Opioides mu/metabolismo , Índice de Gravidade de Doença , Analgésicos Opioides/farmacologia , Animais , Feminino , Pancreatite Necrosante Aguda/tratamento farmacológico , Pancreatite Necrosante Aguda/metabolismo , Ratos , Ratos Wistar , Receptores Opioides mu/genéticaRESUMO
Watercress (Nasturtium officinale) is an aquatic dicotyledonous vegetable belonging to Brassicaceae (Aiton 1812). Watercress was grown in an aquaponic system on fired clay ball medium at the Aquaponic Research Station of the University of Debrecen, in the city of Debrecen (Hungary). During January 2020, 3-month-old plants showed symptoms in aquaponic cultivation. A visual survey showed 30% of plants with symptoms. Leaves and stems withered and showed white cotton-like mycelium. Mycelia from infected plants were placed on potato dextrose agar (PDA) and incubated at 25°C for seven days. Single hyphal tips were transferred to produce a pure culture. All ten fungal isolates showed similar morphological characteristics on PDA. Colonies consisted of white mycelia after three days and globoid to irregular and black 2.5 to 7 (average, 3) mm (n = 100 from ten plates) sclerotia formed ten days later, which are the typical morphological features of Sclerotinia sclerotiorum (Mordue et al. 1976). Molecular identification was performed with one of the ten isolates (Scl_B). Mycelia were grown in 250 ml of potato dextrose broth in a rotary shaker at 175 rpm at 24°C for six days. DNA was extracted from mycelium using a Nucleospin plant II (Macherey-Nagel, Germany) according to the manufacturer's protocol. PCR amplification (Kim et al. 2014) was performed with primers ITS1/ITS4 for the internal transcribed spacer region (White et al. 1990) on a Primus 96 thermal cycler (MWG Biotech, Germany). Specific polymerase chain reaction was performed with primers SSasprF/SSasprR (Abd-Elmagid et al. 2013). PCR products were sequenced by Microsynth Austria GmbH. NCBI BLAST analysis of the 440-bp ITS sequence (Genbank MW012403.1) showed 100% identity with the sequence of S. sclerotiorum (MT177267.1, etc.). The 170-bp specific gene sequence (Genbank MW959042.1) had a 100% similarity to hypothetical proteins (Genbank MK028159.1), with a 99.4% similarity to a portion of the S. sclerotiorum aspartyl protease gene (AF271387.1). Pathogenicity tests were carried out by inoculating surface-disinfested, 30-day-old watercress plants in plastic pots (15x15x12 cm). In three repeated experiments 90 watercress plants were measured. 15 plants (one plant per pot) were planted into the five-times autoclaved substrate (Biorgmix: pH 6.1±0.5%, N:1.5%, P2O5:0.7%, K2O:0.5%, organic matter content:50%) and inoculated by ten wheat kernels that were colonized by S. sclerotiorum (Scl_B) (Garibaldi et al. 2019). 15 plants were planted into the substrate with ten non-inoculated kernels as a control. Plants were kept in an MLR-352 climatic test chamber (PHCbi, Japan) at 21 ± 1°C for 12 hr light:dark cycle. On the first day of the experiment complex nutrient solution (Tek-Land: N:5%, P2O5:5%, K2O:5%, B:0.01%, Cu:0,01%, Mn:0.02%, Mo:0.002%, Zn:0.016%) was used, then autoclaved water daily. Eight days later white mycelium appeared on every inoculated plant and five days later dark sclerotia formed on the stems. Based on the morphological characteristics the re-isolated pathogen was S. sclerotiorum. Similar results were detected in three repeated experiments with white mold fungus being reisolated from all 45 infected watercress plants. The 45 non-inoculated plants did not show any symptoms and any diseases. This pathogen has already been reported on watercress in the field (Farr et al. 1989; Boland and Hall 1994; Garibaldi et al. 2019). This is the first reported case of white mold on watercress in aquaponic system in Hungary.
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Studies of auditory looming bias have shown that sources increasing in intensity are more salient than sources decreasing in intensity. Researchers have argued that listeners are more sensitive to approaching sounds compared with receding sounds, reflecting an evolutionary pressure. However, these studies only manipulated overall sound intensity; therefore, it is unclear whether looming bias is truly a perceptual bias for changes in source distance, or only in sound intensity. Here we demonstrate both behavioral and neural correlates of looming bias without manipulating overall sound intensity. In natural environments, the pinnae induce spectral cues that give rise to a sense of externalization; when spectral cues are unnatural, sounds are perceived as closer to the listener. We manipulated the contrast of individually tailored spectral cues to create sounds of similar intensity but different naturalness. We confirmed that sounds were perceived as approaching when spectral contrast decreased, and perceived as receding when spectral contrast increased. We measured behavior and electroencephalography while listeners judged motion direction. Behavioral responses showed a looming bias in that responses were more consistent for sounds perceived as approaching than for sounds perceived as receding. In a control experiment, looming bias disappeared when spectral contrast changes were discontinuous, suggesting that perceived motion in distance and not distance itself was driving the bias. Neurally, looming bias was reflected in an asymmetry of late event-related potentials associated with motion evaluation. Hence, both our behavioral and neural findings support a generalization of the auditory looming bias, representing a perceptual preference for approaching auditory objects.
Assuntos
Percepção Auditiva/fisiologia , Estimulação Acústica , Adulto , Viés de Atenção/fisiologia , Córtex Auditivo/fisiologia , Sinais (Psicologia) , Eletroencefalografia , Potenciais Evocados/fisiologia , Feminino , Humanos , Masculino , Modelos Neurológicos , Localização de Som/fisiologia , Adulto JovemRESUMO
A study by Tóth, Kocsis, Háden, Szerafin, Shinn-Cunningham, and Winkler [Neuroimage 141, 108 - 119 (2016)] reported that spatial cues (such as interaural differences or ITDs) that differentiate the perceived sound source directions of a target tone sequence (figure) from simultaneous distracting tones (background) did not improve the ability of participants to detect the target sequence. The present study aims to investigate more systematically whether spatially separating a complex auditory "figure" from the background auditory stream may enhance the detection of a target in a cluttered auditory scene. Results of the presented experiment suggest that the previous negative results arose because of the specific experimental conditions tested. Here the authors find that ITDs provide a clear benefit for detecting a target tone sequence amid a mixture of other simultaneous tone bursts.
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Sinais (Psicologia) , Localização de Som , Estimulação Acústica , Percepção Auditiva , Humanos , SomRESUMO
The notion of automatic syntactic analysis received support from some event-related potential (ERP) studies. However, none of these studies tested syntax processing in the presence of a concurrent speech stream. Here we present two concurrent continuous speech streams, manipulating two variables potentially affecting speech processing in a fully crossed design: attention (focused vs. divided) and task (lexical - detecting numerals vs. syntactical - detecting syntactic violations). ERPs elicited by syntactic violations and numerals as targets were compared with those for distractors (task-relevant events in the unattended speech stream) and attended and unattended task-irrelevant events. As was expected, only target numerals elicited the N2b and P3 components. The amplitudes of these components did not significantly differ between focused and divided attention. Both task-relevant and task-irrelevant syntactic violations elicited the N400 ERP component within the attended but not in the unattended speech stream. P600 was only elicited by target syntactic violations. These results provide no support for the notion of automatic syntactic analysis. Rather, it appears that task-relevance is a prerequisite of P600 elicitation, implying that in-depth syntactic analysis occurs only for attended speech under everyday listening situations.
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Atenção/fisiologia , Encéfalo/fisiologia , Linguística , Percepção da Fala/fisiologia , Eletroencefalografia , Potenciais Evocados , Feminino , Humanos , Masculino , Comportamento Multitarefa/fisiologia , Adulto JovemRESUMO
The organization of functional brain networks changes across human lifespan. The present study analyzed functional brain networks in healthy full-term infants (N = 139) within 1-6 days from birth by measuring neural synchrony in EEG recordings during quiet sleep. Large-scale phase synchronization was measured in six frequency bands with the Phase Lag Index. Macroscopic network organization characteristics were quantified by constructing unweighted minimum spanning tree graphs. The cortical networks in early infancy were found to be significantly more hierarchical and had a more cost-efficient organization compared with MST of random control networks, more so in the theta and alpha than in other frequency bands. Frontal and parietal sites acted as the main hubs of these networks, the topological characteristics of which were associated with gestation age (GA). This suggests that individual differences in network topology are related to cortical maturation during the prenatal period, when functional networks shift from strictly centralized toward segregated configurations. Hum Brain Mapp 38:4019-4033, 2017. © 2017 Wiley Periodicals, Inc.
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Encéfalo/fisiologia , Eletroencefalografia , Sono/fisiologia , Feminino , Humanos , Recém-Nascido , Modelos Lineares , Masculino , Vias Neurais/fisiologia , Processamento de Sinais Assistido por ComputadorRESUMO
Statistical learning is a fundamental mechanism of the brain, which extracts and represents regularities of our environment. Statistical learning is crucial in predictive processing, and in the acquisition of perceptual, motor, cognitive, and social skills. Although previous studies have revealed competitive neurocognitive processes underlying statistical learning, the neural communication of the related brain regions (functional connectivity, FC) has not yet been investigated. The present study aimed to fill this gap by investigating FC networks that promote statistical learning in humans. Young adults (N=28) performed a statistical learning task while 128-channels EEG was acquired. The task involved probabilistic sequences, which enabled to measure incidental/implicit learning of conditional probabilities. Phase synchronization in seven frequency bands was used to quantify FC between cortical regions during the first, second, and third periods of the learning task, respectively. Here we show that statistical learning is negatively correlated with FC of the anterior brain regions in slow (theta) and fast (beta) oscillations. These negative correlations increased as the learning progressed. Our findings provide evidence that dynamic antagonist brain networks serve a hallmark of statistical learning.
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Encéfalo/fisiologia , Aprendizagem , Adolescente , Adulto , Ritmo beta , Eletroencefalografia , Feminino , Humanos , Masculino , Probabilidade , Ritmo Teta , Adulto JovemRESUMO
In everyday acoustic scenes, figure-ground segregation typically requires one to group together sound elements over both time and frequency. Electroencephalogram was recorded while listeners detected repeating tonal complexes composed of a random set of pure tones within stimuli consisting of randomly varying tonal elements. The repeating pattern was perceived as a figure over the randomly changing background. It was found that detection performance improved both as the number of pure tones making up each repeated complex (figure coherence) increased, and as the number of repeated complexes (duration) increased - i.e., detection was easier when either the spectral or temporal structure of the figure was enhanced. Figure detection was accompanied by the elicitation of the object related negativity (ORN) and the P400 event-related potentials (ERPs), which have been previously shown to be evoked by the presence of two concurrent sounds. Both ERP components had generators within and outside of auditory cortex. The amplitudes of the ORN and the P400 increased with both figure coherence and figure duration. However, only the P400 amplitude correlated with detection performance. These results suggest that 1) the ORN and P400 reflect processes involved in detecting the emergence of a new auditory object in the presence of other concurrent auditory objects; 2) the ORN corresponds to the likelihood of the presence of two or more concurrent sound objects, whereas the P400 reflects the perceptual recognition of the presence of multiple auditory objects and/or preparation for reporting the detection of a target object.
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Córtex Auditivo/fisiologia , Ondas Encefálicas/fisiologia , Eletroencefalografia/métodos , Reconhecimento Fisiológico de Modelo/fisiologia , Mascaramento Perceptivo/fisiologia , Percepção da Altura Sonora/fisiologia , Reconhecimento Psicológico/fisiologia , Adulto , Mapeamento Encefálico/métodos , Potenciais Evocados Auditivos/fisiologia , Feminino , Humanos , Masculino , Rede Nervosa/fisiologiaRESUMO
MAIN CONCLUSION: Based on the effects of inorganic salts on chloroplast Fe uptake, the presence of a voltage-dependent step is proposed to play a role in Fe uptake through the outer envelope. Although iron (Fe) plays a crucial role in chloroplast physiology, only few pieces of information are available on the mechanisms of chloroplast Fe acquisition. Here, the effect of inorganic salts on the Fe uptake of intact chloroplasts was tested, assessing Fe and transition metal uptake using bathophenantroline-based spectrophotometric detection and plasma emission-coupled mass spectrometry, respectively. The microenvironment of Fe was studied by Mössbauer spectroscopy. Transition metal cations (Cd2+, Zn2+, and Mn2+) enhanced, whereas oxoanions (NO3-, SO42-, and BO33-) reduced the chloroplast Fe uptake. The effect was insensitive to diuron (DCMU), an inhibitor of chloroplast inner envelope-associated Fe uptake. The inorganic salts affected neither Fe forms in the uptake assay buffer nor those incorporated into the chloroplasts. The significantly lower Zn and Mn uptake compared to that of Fe indicates that different mechanisms/transporters are involved in their acquisition. The enhancing effect of transition metals on chloroplast Fe uptake is likely related to outer envelope-associated processes, since divalent metal cations are known to inhibit Fe2+ transport across the inner envelope. Thus, a voltage-dependent step is proposed to play a role in Fe uptake through the chloroplast outer envelope on the basis of the contrasting effects of transition metal cations and oxoaninons.
Assuntos
Transporte Biológico Ativo/fisiologia , Cloroplastos/metabolismo , Ferro/metabolismo , Beta vulgaris/metabolismo , Beta vulgaris/fisiologia , Transporte Biológico Ativo/efeitos dos fármacos , Cádmio/metabolismo , Cloroplastos/efeitos dos fármacos , Cloroplastos/fisiologia , Diurona/farmacologia , Herbicidas/farmacologia , Manganês/metabolismo , Espectroscopia de Mossbauer , Zinco/metabolismoRESUMO
MAIN CONCLUSION: Fe deficiency responses in Strategy I causes a shift from the formation of partially removable hydrous ferric oxide on the root surface to the accumulation of Fe-citrate in the xylem. Iron may accumulate in various chemical forms during its uptake and assimilation in roots. The permanent and transient Fe microenvironments formed during these processes in cucumber which takes up Fe in a reduction based process (Strategy I) have been investigated. The identification of Fe microenvironments was carried out with (57)Fe Mössbauer spectroscopy and immunoblotting, whereas reductive washing and high-resolution microscopy was applied for the localization. In plants supplied with (57)Fe(III)-citrate, a transient presence of Fe-carboxylates in removable forms and the accumulation of partly removable, amorphous hydrous ferric oxide/hydroxyde have been identified in the apoplast and on the root surface, respectively. The latter may at least partly be the consequence of bacterial activity at the root surface. Ferritin accumulation did not occur at optimal Fe supply. Under Fe deficiency, highly soluble ferrous hexaaqua complex is transiently formed along with the accumulation of Fe-carboxylates, likely Fe-citrate. As (57)Fe-citrate is non-removable from the root samples of Fe deficient plants, the major site of accumulation is suggested to be the root xylem. Reductive washing results in another ferrous microenvironment remaining in the root apoplast, the Fe(II)-bipyridyl complex, which accounts for ~30 % of the total Fe content of the root samples treated for 10 min and rinsed with CaSO4 solution. When (57)Fe(III)-EDTA or (57)Fe(III)-EDDHA was applied as Fe-source higher soluble ferrous Fe accumulation was accompanied by a lower total Fe content, confirming that chelates are more efficient in maintaining soluble Fe in the medium while less stable natural complexes as Fe-citrate may perform better in Fe accumulation.
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Cucumis sativus/metabolismo , Ferro/metabolismo , Raízes de Plantas/metabolismo , Xilema/metabolismo , Cucumis sativus/ultraestrutura , Compostos Férricos/metabolismo , Immunoblotting , Compostos de Ferro/metabolismo , Microscopia Eletrônica , Oxirredução , Raízes de Plantas/ultraestrutura , Espectroscopia de MossbauerRESUMO
Cadmium (Cd), a highly toxic heavy metal affects growth and metabolic pathways in plants, including photosynthesis. Though Cd is a transition metal with no redox capacity, it generates reactive oxygen species (ROS) indirectly and causes oxidative stress. Nevertheless, the mechanisms involved in long-term Cd tolerance of poplar, candidate for Cd phytoremediation, are not well known. Hydroponically cultured poplar (Populus jacquemontiana var. glauca cv. 'Kopeczkii') plants were treated with 10 µM Cd for 4 weeks. Following a period of functional decline, the plants performed acclimation to the Cd induced oxidative stress as indicated by the decreased leaf malondialdehyde (MDA) content and the recovery of most photosynthetic parameters. The increased activity of peroxidases (PODs) could have a great impact on the elimination of hydrogen peroxide, and thus the recovery of photosynthesis, while the function of superoxide dismutase (SOD) isoforms seemed to be less important. Re-distribution of the iron content of leaf mesophyll cells into the chloroplasts contributed to the biosynthesis of the photosynthetic apparatus and some antioxidative enzymes. The delayed increase in photosynthetic activity in relation to the decline in the level of lipid peroxidation indicates that elimination of oxidative stress damage by acclimation mechanisms is required for the restoration of the photosynthetic apparatus during long-term Cd treatment.
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Antioxidantes/metabolismo , Cádmio/toxicidade , Cloroplastos/efeitos dos fármacos , Ferro/metabolismo , Populus/efeitos dos fármacos , Adaptação Fisiológica , Biodegradação Ambiental/efeitos dos fármacos , Cádmio/metabolismo , Clorofila/metabolismo , Clorofila A , Cloroplastos/metabolismo , Peróxido de Hidrogênio/metabolismo , Hidroponia/métodos , Malondialdeído/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Peroxidase/metabolismo , Fotossíntese/efeitos dos fármacos , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Proteínas de Plantas/metabolismo , Populus/metabolismo , Populus/fisiologia , Estresse Fisiológico , Superóxido Dismutase/metabolismo , Fatores de TempoRESUMO
The application of sewage sludge has been a worldwide agricultural practice for many years. The present study aimed to investigate the effects of sewage sludge (Ss) has on the physiological parameters of maize (Zea mays L cvs. PR37NO1). 2 g dm(-3) and 4 g dm(-3) of sewage sludge were examined in hydroponic experiment. Some metal contents (Al, Cr, Mn, Na, Zn) in the shoots and roots of maize were taken. Living bacteria containing fertilizers (LBCF) were examined on how the treatments modify heavy metal uptakes. Dry matter accumulations in shoots and roots, length of shoots and roots of maize were measured. Chlorophyll contents were determined by using spectrophotometer methods. The dry matter accumulation and length of shoots decreased, the dry matter of roots increased in all of the treatments compared to the nutrient solution without treatment (control). Increased chlorophyll a, b and carotene contents were observed at 4 g dm(-3) Ss and 4 g dm(-3) Ss + bio fertilizer treatments.
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Agricultura , Conservação dos Recursos Naturais/métodos , Ecossistema , Zea mays/crescimento & desenvolvimento , Monitoramento Ambiental , Fertilizantes , Metais/metabolismo , Esgotos/química , Solo/química , Poluentes do SoloRESUMO
Representations in working memory (WM) are temporary, but can be refreshed for longer periods of time through maintenance mechanisms, thereby establishing their availability for subsequent memory tests. Frontal brain regions supporting WM maintenance operations undergo anatomical and functional changes with advancing age, leading to age related decline of memory functions. The present study focused on age-related functional connectivity changes of the frontal midline (FM) cortex in the theta band (4-8 Hz), related to WM maintenance. In the visual delayed-match-to-sample WM task young (18-26 years, N=20) and elderly (60-71 years N=16) adults had to memorize sample stimuli consisting of 3 or 5 items while 33 channel EEG recording was performed. The phase lag index was used to quantify connectivity strength between cortical regions. The low and high memory demanding WM maintenance periods were classified based on whether they were successfully maintained (remembered) or unsuccessfully maintained (unrecognized later). In the elderly reduced connectivity strength of FM brain region and decreased performance were observed. The connectivity strength between FM and posterior sensory cortices was shown to be sensitive to both increased memory demands and memory performance regardless of age. The coupling of frontal regions (midline and lateral) and FM-temporal cortices characterized successfully maintained trials and declined with advancing age. The findings provide evidence that a FM neural circuit of theta oscillations that serves a possible basis of active maintenance process is especially vulnerable to aging.
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Envelhecimento/fisiologia , Lobo Frontal/fisiologia , Memória de Curto Prazo/fisiologia , Ritmo Teta/fisiologia , Adolescente , Adulto , Idoso , Mapeamento Encefálico , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Estimulação Luminosa , Adulto JovemRESUMO
An open-field 3-year-long microplot experiment was set up with three micropropagated lines (SC Blossom, BFT Indiana, and STM Hajdúsági) of giant reed (Arundo donax L.). Plants were grown on a soil cover of a former sewage settling pond located in Debrecen Lovász-Zug, Hungary. Soil cover of the sewage sediment was moderately contaminated with various toxic elements (As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, and Zn). The highest total concentration of examined toxic elements in leaves was found in the BFT Indiana line (∑326 mg/kg), while in the SC Blossom and STM Hajdúsági lines, ∑210 mg/kg and ∑182 mg/kg were measured, respectively. The highest Zn concentration (117 mg/kg) was found in the leaves of in BFT Indiana line and was 67% higher than that in SC Blossom and 95% more than in the STM Hajdúsági line. The BFT Indiana leaves showed typical signs of adaptation to heavy metal stress in the case of numerous micromorphometric characteristics. The extent of leaf mesophylls decreased, and the number of bulliform cells and phytoliths, as well as the sclerenchymatous stock, increased. The size of the vascular bundles was reduced. The size of the stomata decreased while the stomatal density increased. It can be concluded that the BFT Indiana line had the best adaptational response to heavy metal stress.
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Hyperelastic constitutive laws in biomechanics are used to model soft tissues, and material model parameters are often determined by performing curve fitting on data from uniaxial or biaxial tensile tests. The strain energy function of the applied constitutive law must to be energetically stable; however, this condition is not inherently provided by most currently available models. This study provides a procedure to determine stable strain energy functions in a biaxial strain space based on either uniaxial or biaxial tensile tests. Instead of conservative, strain-independent conditions, a stability region is defined in the strain space based on the sample's tensile tests, thus allowing optimisation within a wider parameter space, resulting in better approximations. An extension of the Levenberg-Marquardt algorithm incorporating user-defined stability constraints is proposed, and the constrained optimisation algorithm is applied to isotropic and anisotropic models. The uniqueness of solutions of the Fung model is also discussed. The material model parameters of stable solutions for soft tissue measurements from various literature sources are determined to demonstrate the proposed procedure. Applying appropriate constraints in the optimisation algorithm resulted in stable and physically permissible constrained solutions for the strain energy function, in contrast to the results of most unconstrained optimisation cases.
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Modelos Biológicos , Estresse Mecânico , Fenômenos BiomecânicosRESUMO
Soil acidity (pH <5.5) limits agricultural production due to aluminum (Al) toxicity. The primary target of Al toxicity is the plant root. However, symptoms can be observed on the shoots. This study aims to determine the potential use of chlorophyll fluorescence imaging, multispectral imaging, and 3D multispectral scanning technology to quantify the effects of Al toxicity on corn. Corn seedlings were grown for 13 days in nutrient solutions (pH 4.0) with four Al treatments: 50, 100, 200, and 400 µM and a control (0 µM AlCl3 L-1). During the experiment, four measurements were performed: four (MT1), six (MT2), 11 (MT3), and 13 (MT4) days after the application of Al treatments. The most sensitive traits affected by Al toxicity were the reduction of plant growth and increased reflectance in the visible wavelength (affected at MT1). The reflectance of red wavelengths increased more significantly compared to near-infrared and green wavelengths, leading to a decrease in the normalized difference vegetation index and the Green Leaf Index. The most sensitive chlorophyll fluorescence traits, effective quantum yield of PSII, and photochemical quenching coefficient were affected after prolonged Al exposure (MT3). This study demonstrates the usability of selected phenotypic traits in remote sensing studies to map Al-toxic soils and in high-throughput phenotyping studies to screen Al-tolerant genotypes.
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Adaptive biases in favor of approaching, or "looming", sounds have been found across ages and species, thereby implicating the potential of their evolutionary origin and universal basis. The human auditory system is well-developed at birth, yet spatial hearing abilities further develop with age. To disentangle the speculated inborn, evolutionary component of the auditory looming bias from its learned counterpart, we collected high-density electroencephalographic data across human adults and newborns. As distance-motion cues we manipulated either the sound's intensity or spectral shape, which is pinna-induced and thus prenatally inaccessible. Through cortical source localisation we demonstrated the emergence of the bias in both age groups at the level of Heschl's gyrus. Adults exhibited the bias in both attentive and inattentive states; yet differences in amplitude and latency appeared based on attention and cue type. Contrary to the adults, in newborns the bias was elicited only through manipulations of intensity and not spectral cues. We conclude that the looming bias comprises innate components while flexibly incorporating the spatial cues acquired through lifelong exposure.