Negative Priming Effect Research Articles

Inhibitory Control was needed in Level-1 Visual Perspective Taking: A Developing Negative Priming Study.

AimPrevious studies have found that both children and adults have difficulties in dealing with judgments in which self-perspective differs from other-perspective, even in level-1 perspective-taking. However, the underlying cognitive mechanism of this is still unclear. In the present study, we designed a negative priming (NP) paradigm of the dot-perspective task to examine whether inhibitory control was required to overcome egocentric bias in level-1 visual perspective-taking in children and adults. We observed an NP effect in both children (n= 43) and adults (n= 40). However, there was no significant difference between children and adults on the magnitude of the NP effect, indicating that when children could overcome the egocentric bias, they had inhibitory control ability comparable to that of adults in level-1 other-perspective-taking.BackgroundVisual perspective-taking is an indispensable ability in social interaction; hence, it has attracted great attention from researchers. However, the mechanism underlying this process remains unclear. The present study aimed to investigate the role of inhibitory control in level-1 visual perspective-taking from a developmental perspective in order to understand the performance differences in perspective-taking tasks between children and adults.MethodsThe NP paradigm was applied to the dot-perspective task. Participants’ response times (RTs) and error rates (ERs) were recorded during the experiment. A 2 (trial type: test vs control, within-subject) × 2 (age: children vs adults) mix-design ANOVA was used to analyse the RTs and ERs data separately.ResultsWe observed an NP effect for both children (7.31, t (42) = 2.78, p < 0.01, Cohen’s d = 0.22) and adults (27.58, t (39) = 2.31, p < 0.05, Cohen’s d = 0.21). However, the difference in the magnitude of the NP effect between children and adults was not significant (t (81) = 0.54, p = 0.59).ConclusionInhibitory control was needed to overcome egocentric bias in level-1 visual perspective-taking for both children and adults. Moreover, when children could overcome egocentric bias, they had an inhibitory control ability comparable to that of adults.

Bidirectional Mapping Between the Symbolic Number System and the Approximate Number System.

Previous studies have discussed the symmetry of bidirectional mapping between approximate number system (ANS) and symbolic number system (SNS). However, these studies neglected the essential significance of bidirectional mapping in the development of numerical cognition. That is, with age, the connection strength between the ANS and SNS in ANS-SNS mapping could be higher than that in SNS-ANS mapping. Therefore, this study attempted to explore the symmetry of bidirectional mapping by examining whether the connection between the ANS and SNS is the same. Using two types of dot array materials (extensive and intensive) and sequence priming paradigms, this study found a stable negative priming effect in the ANS-SNS priming task, but no priming effect in the SNS-ANS priming task. In addition, although sensory cues (extensive and intensive) could affect performance in the ANS-SNS mapping task, these cues did not affect performance in the ANS-SNS priming task. In general, this study provides valuable insight into the symmetry of bidirectional mapping.

Effects of Biochar Feedstock and Pyrolysis Temperature on Soil Organic Matter Mineralization and Microbial Community Structures of Forest Soils

Biochar has received much attention as a strategy to enhance soil carbon (C) sequestration and mitigate climate change. Previous studies found that the feedstock and pyrolysis temperature can largely determine biochar properties, which in turn, impact the stability of native soil organic matter (SOM) and soil microorganisms. The Schima superba and Cunninghamia lanceolata are two tree species widely distributed in the subtropical region of southern China, but how the biochars from these two species influence the soil C sequestration and microbial communities of plantation remain poorly understood. In this study, we produced biochars from these two different feedstocks (13C-labeled S. superba and C. lanceolata litters) at three pyrolysis temperatures (350°C, 550°C, 750°C), then added them to the soils from C. lanceolata plantation, and maintained the experiments at 25°C for 112 days. We found both C mineralization and soil microbial community structures were strongly, but inconsistent, affected by biochar feedstock and pyrolysis temperature. The C. lanceolata biochar triggered the negative priming effect faster and greater compared with the S. superba biochar amendment. Biochars produced at 550°C showed the most significant negative priming effect during the whole incubation period, regardless of the different feedstocks. The cumulative amount of CO2 derived from biochars was significantly decreased with pyrolysis temperature (p &amp;lt; 0.05), indicating that biochars prepared at higher temperatures were more stable in the soil. Further, the soil microbial community structure was only affected by biochar pyrolysis temperature rather than biochar feedstock and their interaction. Together, our results reveal that biochar feedstock and pyrolysis temperature may play more important roles in dictating the priming effect than the structure of microbial community for C. lanceolata plantation. Overall, we concluded that the biochars prepared at 550°C could rapidly decrease the turnover of native SOM in a short term and biochar amendment has the potential to be a management practice for soil C sequestration in the C. lanceolata plantation.

Priming effect varies with root order: A case of Cunninghamia lanceolata

Plant litter inputs can influence soil organic carbon (SOC) decomposition via the priming effect. However, our understanding of the priming effect and underlying mechanisms is primarily from studies with leaf litter addition, while little is known about root litter effects, particularly of woody plants. Here, using a13C natural tracer approach, we conducted a 12-week incubation experiment to investigate litter decomposition and priming effect of mature-tree root orders (1st to 5th) of Cunninghamia lanceolata (Lamb.) Hook. We explored how litter decomposition and the priming effect were related to microbial biomass of main groups, enzyme activities, and root tissue chemistry. Root litter decomposition rates increased with increasing root order, especially during the first 4 weeks, which was likely due to higher non-structural C and lower tannin concentrations for higher order roots. A negative priming effect occurred at this initial intensive stage when microbes may have preferred utilizing litter-derived labile C. Subsequently, the priming effect switched to positive, and showed larger priming effects for the higher order roots than the lower order ones. Higher order roots also showed higher fungi to bacteria ratios and enzyme activities than the lower order roots. These patterns of fungi to bacteria ratios and enzyme activities and thus the priming effect could be attributed to the difference in carbon:nitrogen ratio among root orders. Overall, we for the first time provide strong evidence for the effect of root order on the priming effect, and thus highlight that separating root litter based on root order is necessary for accurately evaluating its influence on SOC decomposition.

Effect of microplastics on organic matter decomposition in paddy soil amended with crop residues and labile C: A three-source-partitioning study

Microplastics (MPs) are a widespread pollutant in terrestrial ecosystems. However, knowledge on how MPs impact soil organic matter (SOM) decomposition and the priming effect (PE) in rice paddy soil remains limited. By employing a three-source-partitioning approach, we investigated the interactive impact of MP dosage (none, low [0.01% w/w] or high [1% w/w]), labile C (14C-labeled glucose), and 13C-labeled rice straw addition on SOM decomposition and PE. Compared to soil without C addition (i.e., control), total SOM-derived CO2 in low-MP soil declined by 13.2% and 7.1% after straw and glucose addition, respectively. Under combined glucose and rice straw addition, glucose-induced PE was up to 10 times stronger in the presence of low-MPs compared to that in high-MPs. However, glucose induced negative PE on rice straw decomposition in the presence of MPs. SOM decomposition was much higher under low MP dosage than under high MP dosage. However, MPs had a negligible effect on the mineralization of exogenous C substrate (glucose or straw). This study provides a novel and valuable insight on how MPs affect SOM turnover and C sequestration in paddy soil, highlighting the significance of interactions between environmental pollutants and biogeochemical processes that affect CO2 fluxes.

Inhibitory control and the understanding of buoyancy from childhood to adulthood

Intuitive conceptions represent common obstacles to conceptual learning in science. A growing number of studies demonstrate that when learning occurs, these intuitive conceptions are not replaced by scientific conceptions but rather coexist with them and thus need to be inhibited to prevent systematic errors. However, to date no study has demonstrated that the increasing ability to mobilize a given scientific conception is rooted in the increasing ability to inhibit the intuitive conception that interferes with it. In the current study, we investigated whether the increasing ability from childhood to adulthood to solve a scientific problem regarding the buoyancy of marbles of different sizes and densities is rooted in the increasing ability to inhibit the “bigger objects sink more” intuitive conception. To do so, we designed a negative priming paradigm in which 11-year-old children, 17-year-old adolescents, and 24-year-old adults were asked to choose which of two marbles of various sizes and densities sinks more. Negative priming effects reported in children and adolescents suggest that, unlike adults, they must inhibit the “bigger objects sink more” intuitive conception to determine, for instance, that a small marble with high density (e.g., small lead marble) will sink more than a bigger marble with a lower density (e.g., big wooden marble). We also found that the amplitude of negative priming effects decreased with age, suggesting that the level of exposition to the scientific knowledge of buoyancy (increasing with age) may decrease the need to inhibit the “bigger objects sink more” intuitive conception.

Microorganisms maintain C:N stoichiometric balance by regulating the priming effect in long-term fertilized soils

Labile carbon (C) inputs affect the soil carbon:nitrogen (C:N) ratio and microbial stoichiometric homeostasis, which control the intensity and direction of the priming effect (PE). Here, we clarified how soil microorganisms regulate enzyme production and PE to maintain the C:N stoichiometric balance. Specifically, we conducted an incubation experiment by adding 13C-labeled glucose to four long-term fertilized paddy soils: no fertilization; fertilization with mineral nitrogen, phosphorus, and potassium (NPK); NPK combined with straw; and NPK with manure (NPKM). After glucose addition, the dissolved organic carbon-to-ammonium (DOC:NH4+) ratio (24–39) initially increased, but subsequently decreased after day 2 following glucose exhaustion. In parallel, the microbial C:N imbalance [(DOC:NH4+):(microbial biomass C:microbial biomass N)] rapidly decreased from day 2 (4.6–7.2) to day 20 (<0.5). Thus, microorganisms became C limited after 20 days of incubation. Excess C, resulting from glucose addition, increased N-hydrolase (chitinase) production and N mining from soil organic matter (SOM) through positive PEs. However, C hydrolase (β-1,4-glucosidase and β-xylosidase) activity increased, while that of N hydrolase (chitinase) decreased, following glucose exhaustion. Consequently, the C:N microbial biomass ratio increased as the DOC:NH4+ ratio decreased, leading to negative PEs. NPKM-fertilized soil had the largest cumulative PE (2.3% of soil organic carbon) because it had the highest microbial biomass and iron (Fe) reduction rate. Thus, this increased N mining from SOM maintained the microbial C:N stoichiometric balance. We concluded that soil microorganisms regulate C- and N-hydrolase production to control the intensity and direction of PE, maintaining the C:N stoichiometric balance in response to labile C inputs.

Responses of Soil Organic Carbon Mineralization and Microbial Communities to Leaf Litter Addition under Different Soil Layers

The mechanism of how soil carbon pools change when coniferous forests are converted into conifer-broadleaf mixed forests is poorly understood. In this study, the impact of additional carbon inputs on soil organic carbon mineralization and microbial communities was evaluated. In a microcosm incubation experiment, three types of 13C-labeled litter (Pinustabulaeformis (PT), Robiniapseudoacacia (RP), and a mixture of PT and RP (1:1, PR)) were added in to top (0–20 cm) and deep (60–80 cm) soil collected from a Chinese pine plantation. The priming effect (PE) and specific microbial groups involved in PE were studied. PT and RP addition to topsoil induced a negative PE. In deep soil, the decomposition rates of soil organic matter (SOM) after adding PT and mixture increased by 16.6% and 34.6% compared to those without litter. The addition of RP with a lower C:N ratio had a stronger negative PE than adding PT or mixture. Moreover, the PE in deep soil was more intense after all litter additions. In topsoil, the litter-derived carbon was mainly incorporated into 16:0, 18:1ω9c, and 18:1ω7c fatty acids. In conclusion, the addition of broadleaf litter into coniferous plantations might be beneficial for enhancing deep soil carbon stocks.

Selective attention to stimulus representations in perception and memory: commonalities and differences

It has been proposed that the deployment of selective attention to perceptual and memory representations might be governed by similar cognitive processes and neural resources. However, evidence for this simple and appealing proposal remains inconclusive, which might be due to a considerable divergence in tasks and cognitive demands when comparing attentional selection in memory versus perception. To examine whether selection in both domains share common attentional processes and only differ in the stimuli they act upon (external vs. internal), we compared behavioral costs or benefits between selection domains. In both domains, participants had to attend a target stimulus from a set of simultaneously presented stimuli or simultaneously active memory representations, respectively, with set, target, or both, being repeated or changed across trials. The results of two experiments delineated principal similarities and differences of selection processes in both domains: While positive priming from stimulus repetition was found in both selection domains, we found no consistent effects of negative priming when shifting the focus of attention to a previously to-be-ignored stimulus. However, priming in the perception task was mainly due to repetitions of the target feature (here: color), whereas for the memory task, repetition of the same set of stimulus representations was most important. We propose that the differences can be attributed to a reduced cognitive effort when the now relevant memory representation had already been pre-activated (even as a distractor) in the previous trial. Additionally, our experiments both underscore the importance of taking stimulus–response associations into account, which may be a hidden factor behind differences between domains. We conclude that any attempt of comparing internal versus external attentional selection has to consider inherent differences in selection dynamics across representational domains.

Priming effects induced by C and N additions in relation to microbial biomass turnover in Japanese forest soils

An understanding of the priming effect (PE), i.e. the effects of carbon (C) and nitrogen (N) inputs on the priming of pre-existing soil organic C mineralization, is fundamental to predicting future soil C cycling and climate feedback. Since the direction and magnitude of the PE depend on the turnover of microbial biomass C and N, we evaluated the PE in relation to pre-existing biomass C and N using dual labeling of glucose 13C and mineral 15N for Japanese moderately acidic (pH of 5.0) cedar and strongly acidic (pH of 4.1) cypress soils. The addition of C only to the cedar soil caused no PE with no change in biomass turnover relative to the control without C or N additions. The addition of N with C caused a positive PE, leading to a net loss of soil C stocks, and decreased pre-existing biomass N due to the higher turnover of biomass N relative to the control. The result for the cedar soil was in line with the stoichiometric decomposition theory but not with microbial N mining theory. By contrast, the addition of C only and both C and N to the cypress soil caused a negative PE. Our study revealed that increasing the pre-existing biomass N turnover can lead to a positive PE, accelerating net soil C loss, when the soil pH does not limit microbial activities.

Effects of substrate quality on carbon partitioning and microbial community composition in soil from an agricultural grassland

The use of organic amendments, including livestock slurry, in intensive grassland soils may result in a temporary increase or decrease in soil organic matter (SOM) mineralisation through microbial activity (positive or negative priming effect, PE). However, the effects of applying organic amendments of different complexity on the activity and composition of the microbial community, as well as on PE, in temperate grassland soils remain unclear. In this study, we hypothesised that the complexity of carbon (C) compounds added to the soil via livestock slurry and in carbohydrate amendments would significantly affect both the partitioning of C and the composition of the soil microbial community. We also hypothesised that applying slurry that had received a biological additive would significantly alter the partitioning of C within the soil and the soil microbial community, compared to an unamended slurry. Microbial community structure, based on phospholipid fatty acid (PLFA) analysis, microbial respiration, and uptake into microbial biomass of 14C-glucose, 14C-glucose-6-phosphate (G6P), and 14C-cellulose, alongside livestock slurry amended or not amended with a biological additive, were investigated in laboratory incubations to test these hypotheses. Both 14C mineralisation and 14C biomass uptake declined significantly as the complexity of the carbohydrate compound added to soil increased (glucose > G6P > cellulose), with the incorporation of C into microbial biomass exceeding respiration of C as CO2 for each compound. The soil microbial community structure was dominated by bacteria over fungi in all treatments through time, with a prevalence of gram-negative over gram-positive bacteria. Our data indicate that adding slurry to soil alongside carbohydrate compounds decreased microbial biosynthesis and the cumulative respiration of carbohydrate compounds, compared to treatments in which slurry was not applied. Our study also indicates that the use of biological additives during slurry storage increased 14C biomass uptake following application of slurry to agricultural grasslands, thus suggesting that biological additives have the potential to enhance soil fertility.

Stream Dissolved Organic Matter in Permafrost Regions Shows Surprising Compositional Similarities but Negative Priming and Nutrient Effects.

Permafrost degradation is delivering bioavailable dissolved organic matter (DOM) and inorganic nutrients to surface water networks. While these permafrost subsidies represent a small portion of total fluvial DOM and nutrient fluxes, they could influence food webs and net ecosystem carbon balance via priming or nutrient effects that destabilize background DOM. We investigated how addition of biolabile carbon (acetate) and inorganic nutrients (nitrogen and phosphorus) affected DOM decomposition with 28‐day incubations. We incubated late‐summer stream water from 23 locations nested in seven northern or high‐altitude regions in Asia, Europe, and North America. DOM loss ranged from 3% to 52%, showing a variety of longitudinal patterns within stream networks. DOM optical properties varied widely, but DOM showed compositional similarity based on Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS) analysis. Addition of acetate and nutrients decreased bulk DOM mineralization (i.e., negative priming), with more negative effects on biodegradable DOM but neutral or positive effects on stable DOM. Unexpectedly, acetate and nutrients triggered breakdown of colored DOM (CDOM), with median decreases of 1.6% in the control and 22% in the amended treatment. Additionally, the uptake of added acetate was strongly limited by nutrient availability across sites. These findings suggest that biolabile DOM and nutrients released from degrading permafrost may decrease background DOM mineralization but alter stoichiometry and light conditions in receiving waterbodies. We conclude that priming and nutrient effects are coupled in northern aquatic ecosystems and that quantifying two‐way interactions between DOM properties and environmental conditions could resolve conflicting observations about the drivers of DOM in permafrost zone waterways.

Positive and negative priming effects in an Ultisol in relation to aggregate size class and biochar level

The priming effect in soils is known to depend in part on the size distribution and decomposability of aggregate-associated soil organic carbon. However, the biochar-induced carbon mineralization priming effects within aggregates of different size classes are poorly understood. In this study, the bulk soils were firstly separated into three fractions (>1 mm macroaggregate, 0.25−1 mm macroaggregate, and <0.25 mm microaggregate). Then, the bulk soils and different aggregate-size fractions were incubated for 180 days following the incorporation of biochar (C4 source) with two levels (2.5 % and 5.0 %). Sources of C decomposition (biochar derived C, primed C, and basal soil derived C) were partitioned. The percent of biochar-derived CO2 emission to the total mineralized C increased as the aggregate size decreased. The short-term positive priming effects appeared in the early stage for all three aggregate-size fractions. Predominantly negative priming effects were observed after 56 days of incubation in the bulk soils and>0.25 mm macroaggregates. However, a weak negative priming effect was only detected after 180 days at a high biochar level in the <0.25 mm microaggregates. Furthermore, much stronger repression of soil C mineralization was induced by a higher biochar level, with 10.1–53.4 % higher negative priming effects under 5.0 % biochar treatments than 2.5 % biochar treatments over 180 days. The results suggest that a greater portion of total readily decomposable soil organic C in >0.25 mm macroaggregates has probably been protected by biochar amended and made unavailable. Our study indicates that the priming effects of biochar on the soil organic carbon in Ultisols depend on the aggregate size.

The detrimental impacts of negative age stereotypes on the episodic memory of older adults: does social participation moderate the effects?

BackgroundOlder adults’ cognitive abilities can be impaired through priming of negative age stereotypes. However, it is unclear whether the effects of negative priming can be extended to episodic memory, which is believed to be the most age-sensitive type among the long-term memory systems, in Asian populations. Social participation has recently emerged as a potential protective factor for maintaining the cognitive function of older adults. The purpose of this study was to examine the effects of negative age stereotype priming on episodic memory and the moderating role of social participation in the priming effect.MethodsA total of 105 community-dwelling older adults residing in Hong Kong were randomly allocated to two experimental conditions. Participants were primed either with negative age stereotype words (n = 53) or neutral words (n = 52) using an implicit priming task. Episodic memory performance was assessed using the Hong Kong List Learning Task (HKLLT), which includes total learning, two delayed recalls and a recognition task. Analysis of covariance (ANCOVA) was used to assess group differences in the priming task and memory performance, while a series of moderation analyses were performed to examine the moderating effects of social participation.ResultsThe group that received negative age stereotype priming performed significantly worse than the group that received neutral words in their episodic memory test. Additional analyses showed that socially active individuals might be less prone to the effects of negative age stereotypes for the recognition task only.ConclusionsOlder adults who are more socially active might be more immune to the effects of negative age stereotype priming on episodic memory. These results provide initial support for the hypothesis that social participation might act as an effective strategy to ward against negative age stereotype priming.Trial registrationClinicalTrials.gov: NCT04202120 (first posted December 17, 2019), (Retrospectively registered).

Application of biochar in estrogen hormone-contaminated and manure-affected soils: Impact on soil respiration, microbial community and enzyme activity

Biochar as a soil amendment has been proposed for enhancing carbon sequestration and manure-borne hormone contaminant remediation. However, little is known about the ecological risk of biochar application in the soil with hormone contamination. This study investigated the influence of biochar in three manure-impacted soils contaminated with estrogen hormones, natural estrogen 17β-estradiol and synthesized estrogen 17α-ethinylestradiol in a microcosm experiment. Specifically, microbial respiration was periodically determined during microcosm incubation while microbial community phospholipid fatty acids and activities of nutrient (C, N, P, S) cycling related enzymes (β-glucosidase, urease, phosphodiesterase, arylsulfatase) were characterized after the incubation. Results showed that the manure-impacted soils with high SOC generally had greater total microbial biomass, ratios of fungi/bacteria and Gram-positive bacteria/Gram-negative bacteria, and phosphodiesterase activity, but lower urease activity. Additionally, hormones stimulated microbial respiration and biomass, while had little impact on activity of the enzymes. On the other hand, biochar showed negative priming effect by significantly decreasing total microbial biomass by 8.7%–26.4%, CO2 production by 16.6%–33.5%, and glucosidase activity by 27.1%–41.0% in the three soils. Biochar significantly increased the activity of phosphodiesterase, showed no impact on arylsulfatase, while decreased the activity of urease. Overall, the study suggests that when used in hormone remediation in manure-impact soils, biochar could improve phosphodiesterase activity, but may decrease soil microbial activity and the activity of soil glucosidase and urease.

Contrasting response of organic carbon mineralisation to iron oxide addition under conditions of low and high microbial biomass in anoxic paddy soil

In contrast to what is observed in aerobic uplands, microbial biomass and the presence of electron acceptors, such as iron oxides, play a crucial role in regulating soil organic C (SOC) mineralisation in paddy soils. However, the related underlying mechanisms are still poorly explored. We conducted an anaerobic incubation study to investigate changes in CO2 emissions from SOC and acetate (13C-labeleld) in response to iron oxide (ferrihydrite and goethite) addition in chloroform-fumigated and unfumigated paddy soils. The iron oxides, as electron acceptors, increased CO2 emissions from SOC with stronger impact under ferrihydrite than goethite addition. However, the acetate addition, as a preferable C source for reducing microbes, decreased SOC mineralisation and caused a negative priming effect. CO2 emission from both acetate and SOC was affected by microbial biomass change. In the acetate-treated soil, goethite in the fumigated soil (i.e. high microbial biomass) increased CO2 emissions from acetate, providing electron acceptors, and decreased CO2 emissions from SOC. Ferrihydrite accepted electrons and adsorbed acetate, resulting in a slight decline in CO2 emission from acetate. However, in the fumigated soil (i.e. low microbial biomass), both iron oxide additions reduced CO2 emissions from acetate and SOC and likely the dominant role of both iron oxides shifted from being electron acceptors to being adsorbents, thus limiting acetate accessibility to microorganisms. The results suggest that microbial biomass is a key driver in shifting the effects of iron oxides on organic C mineralisation in anaerobic paddy soils.

Probing the causal involvement of dlPFC in directed forgetting using rTMS-A replication study.

The forgetting of previously remembered information has, for a long time, been explained by purely passive processes. This viewpoint has been challenged by the finding that humans show worse memory for specific items that they have been instructed to forget. The dorsolateral prefrontal cortex has, through imaging, lesion and brain stimulation studies, been implied in controlling such active forgetting processes. In this study, we attempted to solidify evidence for such a causal role of the dlPFC in directed forgetting by replicating an existing rTMS study (Hanslmayr S, 2012) in a preregistered within-participant design. We stimulated participants at the dlPFC (BA9) or vertex using 45s of 1Hz rTMS after instructions to forget previously remembered words in a list-method directed forgetting paradigm and tested for effects on the amount of forgotten information. Contrary to the study we were attempting to replicate, no significant increase in forgetting under dlPFC stimulation was found in our participants. However, when combining our results with the study we were attempting to replicate, dlPFC stimulation led to significantly increased directed forgetting in both studies combined. We further explored if the rTMS parameters used here and in earlier work (Hanslmayr S, 2012) influenced inhibitory processing at their time of delivery or in a more persistent manner. Unaltered incongruency and negative priming effects in a Stroop task conducted directly after stimulation suggests that our rTMS stimulation did not continue to influence inhibitory processing after the time of stimulation. As the combined evidence for increased directed forgetting due to rTMS dlPFC stimulation is still quite weak, additional replications are necessary to show that directed forgetting is indeed causally driven by an active prefrontal process.

Gain in carbon: Deciphering the abiotic and biotic mechanisms of biochar-induced negative priming effects in contrasting soils

The biochar-induced priming effects (PEs) were investigated by applying maize straw (C4) derived biochar to eight C3 soils, with a gradient of pH and a sub-gradient of soil organic carbon (SOC). To decipher the physicochemical and microbial mechanisms, we adopted C-isotopic analysis, high-throughput sequencing and multivariate statistical analyses such as random forest (RF) and structure equation modeling (SEM). Negative and neutral PEs were observed up to −48.5% of relative PEs during 28 days of incubation. All the acidic soils exhibited negative PEs, so as the neutral Alfisol and alkaline Aridisol, which had a suppression effect on SOC mineralization accounted for −29.4 and −32.0% of relative PEs. Among all abiotic factors, soil silt-clay fraction and the initial pH values play the most important roles in PEs determination through directly inhibiting PEs by protection SOC and indirectly shaping bacterial communities respectively. On the whole community level, biochar treatments defined much less microbiome (0.6% and 1.2% for variance of bacterial and fungal community) than soil types (93.5% and 83.3% respectively) across soils. Thus, the initial community (i.e., bacteria alpha-diversity and copiotrophic bacteria as revealed by SEM) of different soils might be more critical for PE prediction. Furthermore, co-occurrence network analysis indicated out-competition of fungi by bacteria with increase of mutual exclusion and decrease of fungal occupancy. This could exacerbate negative PEs in soils with lower bacterial alpha-diversity and dominance by copiotrophys due to less functional complementary for recalcitrant SOC decomposition.

Beyond Clinical Outcomes: Posttraumatic Stress Symptoms Favor Attentional and Memory Control Abilities for Trauma-Related Words.

Memory alterations and biases are core features of posttraumatic stress symptoms (PTSS). Although a large number of studies have investigated memory biases associated with PTSS, some inconsistencies remain regarding the nature of the mechanisms behind the threat-related biases observed in prior findings. The present study explored the extent to which inhibitory deficits, both for automatic and controlled processes, can account for these biases. Participants (N = 64) took part in a remember/know recognition procedure for positive, neutral, negative, and trauma-related words associated with negative priming and directed forgetting encoding. Half of the participants had high levels of PTSS (i.e., PCL-5 score > 40) and half had low levels (i.e., total PCL-5 score < 20). As both negative priming and directed forgetting effects are posited to depend on inhibitory abilities, we expected these effects to be absent for trauma-related words in participants with more severe PTSS. Replicating classic memory biases, participants with high levels of PTSS produced more "remember" recognition responses for trauma-related words, ηp 2 = .10. However, contrary to our expectations, directed forgetting, ηp 2 = .26; and negative priming effects were observed for trauma-related words but not for words of other valences, ηp 2 = .07 and .06, respectively. Hence, rather than the expected inhibitory deficits, our results suggest that PTSS preserve the ability to inhibit trauma-related information in both attentional and memory processes. As it appears to occur at the expense of other information, this preserved cognitive functioning for trauma-related stimuli is discussed with regard to resource reallocation theories.

Effect of Biochar on Soil Respiration from a Semi-evergreen, Moist Deciduous Forest Soil

Mineralization of soil organic carbon has a significant impact on the atmospheric CO2 concentration. Application of organic amendments can affect the dynamics of carbon present in soil through the process of mineralization and immobilization. This study assessed the efficiency of biochar on soil carbon mineralization through respiration and the priming effect (positive or negative) after addition of the external carbon biomass in a controlled incubation experiment (90 days) at two different temperature regimes viz. 15 °C and 30 °C. A decrease in total CO2 respired was found with the addition of biochar in the soil where 6 t ha−1 of biochar treatment (T7) produced the lowest amount of CO2 for both the temperature regimes. The calculated half-life (t1/2) and rate constant (k) showed resistivity towards mineralization with increasing doses of biochar. Significantly negative priming effects were observed with addition of biochar in comparison to the control treatment at the end of the incubation period.