Why Does Cognitive Training Yield Inconsistent Benefits? A Meta-Analysis of Individual Differences in Baseline Cognitive Abilities and Training Outcomes

Despite growing interest in improving cognitive abilities across the lifespan through training, the benefits of cognitive training are inconsistent. One powerful contributor may be that individuals arrive at interventions with different baseline levels of the cognitive skill being trained. Some evidence suggests poor performers benefit the most from cognitive training, showing compensation for their weak abilities, while other evidence suggests that high performers benefit most, experiencing a magnification of their abilities. Whether training leads to compensation or magnification effects may depend upon the specific cognitive domain being trained (such as executive function or episodic memory) and the training approach implemented (strategy or process). To clarify the association between individual differences in baseline cognitive ability and training gains as well as potential moderators, we conducted a systematic meta-analysis of the correlation between these two variables. We found evidence of a significant meta-correlation demonstrating a compensatory effect, a negative association between initial ability on a trained cognitive process and training gains. Too few papers met our search criteria across the levels of proposed moderators of cognitive domain and training approach to conduct a reliable investigation of their influence over the meta-analytic effect size. We discuss the implications of a compensatory meta-correlation, potential reasons for the paucity of qualifying papers, and important future directions for better understanding how cognitive trainings work and for whom.

The Compensation Effect Mechanism of Fe-Ni Mixed Prussian Blue Analogues in Aqueous Rechargeable Aluminum-Ion Batteries

An aluminum-ion battery was assembled with potassium nickel hexacyanoferrate (KNHCF) as a cathode and Al foil as an anode in aqueous electrolyte for the first time, based on Al³⁺ intercalation and deintercalation. A combination of ex situ XRD, X-ray photoelectron spectroscopy (XPS), galvanostatic intermittent titration technique (GITT), and differential capacity analysis was used to unveil the crystal structure changes and the insertion/extraction mechanism of Al³⁺ . Al³⁺ could reversibly insert/extract into/from KNHCF nanoparticles through a single-phase reaction with reduction/oxidation of Fe and Ni. Over long-term cycling, it was Fe rather than Ni that contributed to more capacity owing to the dissolution of Ni from the KNHCF structure, which could be expressed as a compensation effect of mixed redox centers in KNHCF. KNHCF delivered an initial discharge capacity of 46.5 mAh g^-1 . The capacity decay could be attributed to the unstable interface between Al foil and the aqueous electrolyte owing to the catalytic activity of the Ni transferring from Ni dissolution of KNHCF to the Al foil anode, rather than KNHCF structure collapse; KNHCF maintained its 3 D framework structure for 500 cycles. This work is expected to inspire more exhaustive investigations of the mechanisms that occur in aluminum-ion batteries.

Electron Transfer Proteins as Electronic Conductors: Significance of the Metal and Its Binding Site in the Blue Cu Protein, Azurin

Electron transfer (ET) proteins are biomolecules with specific functions, selected by evolution. As such they are attractive candidates for use in potential bioelectronic devices. The blue copper protein azurin (Az) is one of the most-studied ET proteins. Traditional spectroscopic, electrochemical, and kinetic methods employed for studying ET to/from the protein's Cu ion have been complemented more recently by studies of electrical conduction through a monolayer of Az in the solid-state, sandwiched between electrodes. As the latter type of measurement does not require involvement of a redox process, it also allows monitoring electronic transport (ETp) via redox-inactive Az-derivatives. Here, results of macroscopic ETp via redox-active and -inactive Az derivatives, i.e., Cu(II) and Cu(I)-Az, apo-Az, Co(II)-Az, Ni(II)-Az, and Zn(II)-Az are reported and compared. It is found that earlier reported temperature independence of ETp via Cu(II)-Az (from 20 K until denaturation) is unique, as ETp via all other derivatives is thermally activated at temperatures >≈200 K. Conduction via Cu(I)-Az shows unexpected temperature dependence >≈200 K, with currents decreasing at positive and increasing at negative bias. Taking all the data together we find a clear compensation effect of Az conduction around the Az denaturation temperature. This compensation can be understood by viewing the Az binding site as an electron trap, unless occupied by Cu(II), as in the native protein, with conduction of the native protein setting the upper transport efficiency limit.

Physiological responses of two moss species to the combined stress of water deficit and elevated N deposition (II): Carbon and nitrogen metabolism

Nitrogen (N) deposition levels and frequencies of extreme drought events are increasing globally. In efforts to improve understanding of plants' responses to associated stresses, we have investigated responses of mosses to drought under elevated nitrogen conditions. More specifically, we exposed Pogonatum cirratum subsp. fuscatum and Hypnum plumaeforme to various nitrate (KNO 3) or ammonium (NH 4Cl) treatments, with and without water deficit stress and monitored indices related to carbon (C) and N metabolism both immediately after the stress and after a short recovery period. The results show that N application stimulated both C and N assimilation activities, including ribulose-1,5-bisphosphate carboxylase, glutamine synthetase/glutamate synthase (GS/GOGAT), and glutamate dehydrogenase (GDH) activities, while water deficit inhibited C and N assimilation. The mosses could resist stress caused by excess N and water deficit by increasing their photorespiration activity and proline (Pro) contents. However, N supply increased their sensitivity to water stress, causing sharper reductions in C and N assimilation rates, and further increases in photorespiration and Pro contents, indicating more serious oxidative or osmotic stress in the mosses. In addition, there were interspecific differences in N assimilation pathways, as the GS/GOGAT and GDH pathways were the preferentially used ammonium assimilation pathways in P. cirratum and H. plumaeforme when stressed, respectively. After rehydration, both mosses exhibited overcompensation effects for most C and N assimilation activities, but when supplied with N, the activities were generally restored to previous levels (or less), indicating that N supply reduced their ability to recover from water deficit stress. In conclusion, mosses can tolerate a certain degree of water deficit stress and possess some resilience to environmental fluctuations, but elevated N deposition reduces their tolerance and ability to recover.

Tau haploinsufficiency causes prenatal loss of dopaminergic neurons in the ventral tegmental area and reduction of transcription factor orthodenticle homeobox 2 expression

Homozygous tau knockout (Mapt^-/-) mice develop age-dependent dopaminergic (DA) neuronal loss in the substantia nigra (SN) and ventral tegmental area (VTA), supporting an important function of tau in maintaining the survival of midbrain dopaminergic neurons (mDANs) during aging. However, it remains to be determined whether the microtubule-associated protein tau regulates the differentiation and survival of mDANs during embryonic developmental stages. Here, we show that tau haploinsufficiency in postnatal day 0 (P0) heterozygous (Mapt^+/-) pups, but not a complete loss of tau in the Mapt^-/- littermates, led to a significant reduction of DA neurons in the VTA. This selective loss of DA neurons correlated with a similar reduction in orthodenticle homeobox 2 (Otx2), which is restricted to VTA neurons at the postmitotic stage and selectively controls the neurogenesis and survival of specific neuronal subtypes of VTA. Moreover, the prenatal developmental cell death in the Mapt^+/- VTA specifically increased, and the expression of microtubule-associated protein (MAP)-1A was significantly up-regulated in the P0 Mapt^-/- , but not the Mapt^+/- , pups. These results suggest that tau haploinsufficiency, without the compensation effect of MAP1A, induces reduction of Otx2 expression, increases prenatal cell death, and accordingly leads to selective loss of VTA DA neurons in the early postnatal stage. Our findings highlight the impact of tau haploinsufficiency on the survival of mDANs and indicate that tau may participate in midbrain development in a dose-dependent way.-Zheng, M., Jiao, L., Tang, X., Xiang, X., Wan, X., Yan, Y., Li, X., Zhang, G., Li, Y., Jiang, B., Cai, H., Lin, X. Tau haploinsufficiency causes prenatal loss of dopaminergic neurons in the ventral tegmental area and reduction of transcription factor orthodenticle homeobox 2 expression.

The Impact of Having One Parent Absent on Children' Food Consumption and Nutrition in China

The rapid economic and social development in the past decades has greatly increased the societal acceptance of divorce and non-marital pregnancies in China, which leads to a soaring number of single-parent children. This paper aimed to investigate the impact of having one parent absent on children' food consumption and nutrition status. We extracted 1114 children from a longitudinal household survey data in China, all of which were observed twice. Using the Propensity Score Matching and Difference-in-Difference methods, we found that being raised by one parent does not have a negative effect on children's food consumption and nutrition intake. On the contrary, single-parent families tend to provide more food to their children as a compensation for the absence of one parent and this compensation effect offsets the negative impact caused by declined family income. Particularly, urban, rich families had stronger compensation effect than other families with low and middle incomes.

Differential Effects of Monetary and Social Rewards on Product Online Rating Decisions in E-Commerce in China

Humans can change their behaviors to obtain environmental rewards (e.g., money, food, and sex). However, our knowledge regarding how rewards affect human behaviors by priming and whether there are differences among types of rewards is limited. This study focused on whether monetary and social rewards have different priming effects on product rating decisions in e-commerce by using a behavioral experiment and event-related potentials (ERPs). Using cash/discount coupons as a monetary reward and greeting cards as a social reward, the behavioral data showed that unsatisfactory products with a monetary reward induced a less negative consumer attitude than those with a social reward or no reward; additionally, such products were associated with a longer reaction time while rating products than those with a social reward, reflecting that monetary rewards made it more difficult for the subjects to rate unsatisfactory products than social rewards. The P2, N2, and P3 components of the ERP data were evaluated. Unsatisfactory products caused negative emotion, which could be compensated more by the monetary reward than the social reward as reflected by a smaller P2 amplitude. Due to the compensation effect of the monetary reward, unsatisfactory products were associated with more decision conflict than the social reward as reflected by a more negative N2 amplitude, which is consistent with the behavioral results. However, in the subsequent controlled process, regardless of whether the products were satisfactory or unsatisfactory, the monetary reward caused more attention reallocation and was more motivating than the social reward as reflected by a larger P3 component. These findings have implications for the marketing strategy of online sellers and value of online reviews and suggest attaching importance to ethical issues induced by monetary rewards in rating behaviors.

Nitrogen Addition Exacerbates the Negative Effects of Low Temperature Stress on Carbon and Nitrogen Metabolism in Moss

Global environmental changes are leading to an increase in localized abnormally low temperatures and increasing nitrogen (N) deposition is a phenomenon recognized worldwide. Both low temperature stress (LTS) and excess N induce oxidative stress in plants, and excess N also reduces their resistance to LTS. Mosses are primitive plants that are generally more sensitive to alterations in environmental factors than vascular species. To study the combined effects of N deposition and LTS on carbon (C) and N metabolism in moss, two moss species, Pogonatum cirratum subsp. fuscatum, and Hypnum plumaeforme, exposed to various concentrations of nitrate (KNO3) or ammonium (NH4Cl), were treated with or without LTS. C/N metabolism indices were then monitored, both immediately after the stress and after a short recovery period (10 days). LTS decreased the photosystem II (PSII) performance index and inhibited non-cyclic photophosphorylation, ribulose-1,5-bisphosphate carboxylase, and glutamine synthetase activities, indicating damage to PSII and reductions in C/N assimilation in these mosses. LTS did not affect cyclic photophosphorylation, sucrose synthase, sucrose-phosphate synthase, and NADP-isocitrate dehydrogenase activities, suggesting a certain level of energy and C skeleton generation were maintained in the mosses to combat LTS; however, LTS inhibited the activity of glycolate oxidase. As predicted, N supply increased the sensitivity of the mosses to LTS, resulting in greater damage to PSII and a sharper decrease in C/N assimilation. After the recovery period, the performance of PSII and C/N metabolism, which were inhibited by LTS increased significantly, and were generally higher than those of control samples not exposed to LTS, suggesting overcompensation effects; however, N application reduced the extent of compensation effects. Both C and N metabolism exhibited stronger compensation effects in H. plumaeforme than in P. cirratum subsp. fuscatum. The difference was especially pronounced after addition of N, indicating that H. plumaeforme may be more resilient to temperature and N variation, which could explain its wider distribution in the natural environment.

Nature of AX centers in antimony-doped cadmium telluride nanobelts

Single crystalline p-type CdTe:Sb nanobelts were fabricated using an Au-catalyzed chemical vapor deposition method. Low carrier concentration and low mobility even at high Sb incorporation manifest compensation in the system. From cross examination of temperature-dependent charge transport and photoluminescence measurements, two major acceptor levels induced by Sb doping are determined: a shallow level attributed to substitutional Sb dopants without lattice relaxation and an associated deeper level resulted from large lattice relaxation-AX centers. Persistent photoconductivity and hysteresis photoconductance under the thermal cycle elucidate the nature of AX centers. This comprehensive investigation of the impurity levels in the material system is essential for the design and development of nanoelectronic devices based on the CdTe nanostructures.

Effects of resin-tapping on radial variation of sap flow density and whole tree transpiration in Pinus massoniana

We investigated the effects of resin-tapping on the radial differences of sap flow density and whole-tree transpiration in Pinus massoniana. We used the Granier's thermal diffusion probe method to measure sap flow density at different sapwood depths on non-resin-tapped P. massoniana and both the non-resin-tapped surface and resin-tapped surface of resin-tapped P. massoniana, that had undergone continuous resin tapping from 2004 to 2015. The results showed that the radial distribution patterns of sap flow density in the non-resin-tapped P. massoniana and on the non-resin-tapped surface of resin-tapped P. massoniana were unimodal, while that on the resin-tapped surface of resin-tapped P. massoniana was irregular. Resin-tapping altered the radial distribution pattern of sap flow density on the resin-tapped surface of resin-tapped P. massoniana. In addition, the sap flow density on the resin-tapped surface of P. massoniana was significantly lower than that on the non-resin-tapped surface, indicating that resin tapping reduced water transport capacity of the tapped surfaces. Except for the outer layer (0-2 cm), the density of sap flow on the non-resin-tapped surface was higher than that on the corresponding sapwood depth of the non-resin-tapped P. massoniana in other layers (2-10 cm), which would compensate the decreased water transport capacity of the resin-tapped surface. Furthermore, the whole-tree average daily sap flow density in resin-tapped P. massoniana (710.4 kg·m-2·d-1) was 82.9% of that in the non-resin-tapped P. massoniana (856.63 kg·m-2·d-1), indicating that the increase in sap flow density on the non-resin-tapped surface could not fully compensate for the decline in water transport capacity of the resin-tapped surface, resulting in a decrease in the overall water transport capacity of the resin-tapped P. massoniana. Moreover, the appearing time of whole-tree daily maximum sap flow density in resin-tapped P. massoniana occurred approximately 1 hour earlier than that of non-resin-tapped P. massoniana, indicating that the decrease in whole-tree water transport capacity caused by resin-tapping had led to moisture deficiency in resin-tapped P. massoniana. There was significant correlation between whole-tree sap flow density and sap flow density in various depths on the non-resin-tapped surface of resin-tapped P. massoniana and non-resin-tapped P. massoniana. By developing an estimation method for the average tree sap flow density based on the easily measurable surface sap flow density, we could obtain a more accurate assessment of overall tree transpiration.

Plastic Devolatilisation Kinetics During Isothermal High-Temperature Pyrolysis: Focus on Solid Products (Part I)

Incineration remains Europe's main practice for plastic packaging waste treatment, primarily due to the limitations of mechanical recycling technology. Consequently, research and development of more sustainable and flexible approaches are of high importance. Thermochemical conversion of polypropylene, polystyrene, and municipal plastic packaging mix via high-temperature flash pyrolysis (1000 °C/s) is studied in this research, focusing on the kinetics and yields of the devolatilisation stage. The primary stage results in the formation of volatile organic compounds considered intermediate products for carbon black production. The experiments were conducted in a pressurised wire mesh reactor, investigating the influence of temperature (600-1200 °C), residence time (0.5-10 s), and pressure (1-25 bar). The positive effect of temperature on the volatile yield was observed up to 2-5 s. The devolatilisation stage was completed within a maximum of 5 s at temperatures ranging from 800 to 1200 °C. The pressure was determined to be a kinetically limiting factor of the process to up to 800 °C, and the effect was not present at ≥1000 °C. Raman spectroscopy measurements revealed that pyrolytic carbon deposited on the post-experimental meshes is structurally similar to the industrially produced carbon black. The kinetic data and developed model can be further applied in the upscale reactor design.

[Compensation effect of re-watering after different drought stresses on source-sink metabolism during tuber expansion period of potato.]

The compensation effect of re-watering after drought has been widely reported in various crops during different growth stages. It is considered as an important self-regulation mechanism for plants to resist abiotic stresses and also an efficient utilization of limited water resource. In this study, two rounds of re-watering after drought treatments were carried out during tuber expansion period of potato, to investigate the drought threshold of potato and explore the potential mechanisms of compensation effect with source-sink aspect. We used virus-free plantlets of "Atlantic" potato as experimental materials. Four treatments were included: sufficient water supply (W), re-watering after mild drought (D₁-W), re-watering after medium drought (D₂-W) and re-watering after severe drought (D₃-W). The results showed that potato yield exhibited an over-compensation effect after two rounds of D₁-W treatment, with water use efficiency and yield being increased by 17.5% and 6.3%, respectively, compared with the sufficient water supply. D₂-W treatment had no significant effect on potato yield, but water use efficiency was increased by 8.4%, indicating a near-equivalent compensation effect. On the contrary, D₃-W treatment did not show any compensation effect in yield. In addition, leaf chlorophyll content, net photosynthetic rate, and leaf area were all reduced after drought treatment, indicating a reduction in "source" size and activity. After re-watering, D₁-W and D₂-W treatments showed over-compensation and compensation effects through improving source supply capacity. Meanwhile, re-watering after moderate drought increased the sink activity through significantly enhancing the activities of key enzymes in tubers (sink), thus increased the average weight of tubers. In conclusion, re-watering after moderate drought stress during potato tuber expansion period had compensation and over-compensation effects on both source and sink, and thus could compensate for the drought-induced yield loss and improve water use efficiency.

Paired nerve stimulation with selective compensation effect

Background

In this study we investigate the selective compensation of paired peripheral nerves in healthy humans, focusing on distinct axonal conduction velocities in different fibre types. Using paired associative stimulation (PAS) with adjustable parameters, we aimed to modulate and compensate for neuronal activity along the median nerve.

Methods

Six healthy volunteers (3 male, 3 female, aged: 22-49) participated in the current study. We conducted 30 experiments with the following protocol. A pair of pulses with the following parameters were applied to each volunteer: amplitude, pulse width and inter-pulse delay was generated by the dual-core programmed microcontroller STM32H745xI/G while values were set by one-board computer Jetson Nano. The microcontroller provided a pair of pulses to the DAC that applied it to nerve stimulation sites via a stimulator. During experiments, we used the following ranges: (a) current amplitudes [0-20mA], (b) pulse width [250-500 μs] and (c) delays [50-250 μs]. As the measurement of the stimulation effectiveness, we used the finger's contraction angles.

Results

Our findings reveal a significant selective compensation (inhibitory) effect over the motor responses, demonstrated through variations in finger displacement angles. By optimizing individual parameters-pulse width, inter-pulse delay, and compensatory currents-we successfully induced motor response compensation effects. Notably, consistent compensatory effects were observed across all volunteers using a pulse width of (250 μs) and an inter-pulse delay of (50 μs).

Discussion

These results highlight PAS's potential for developing non-invasive neuromodulation devices. However, further research is required to evaluate its efficacy in individuals with spasticity and upper motor neuron deficits.

The compensation effect of competence frustration and its behavioral manifestations

The frustration of competence, one of the three basic psychological needs proposed by self-determination theory, has been widely demonstrated to negatively influence one's motivation and well-being in both work and life. However, research on the recovery mechanism of competence is still in the nascent stage. In this study, a two-stage behavioral experiment was conducted to examine the restoration of competence and the potential moderating role of resilience. Results showed that individuals who were asked to recall experience of competence frustration performed better on subsequent tasks, manifesting their behavioral efforts of competence restoration. However, resilience does not play a significant moderating role in competence restoration. Through convergent behavioral evidence, findings of this study demonstrate the compensation effect of competence frustration.

Amine-Modified ZIF Composite Membranes: Regulated Nanochannel Interactions for Enhanced Cation Transport and Precise Separation

Electromembrane water treatment technologies are attracting attention for their energy efficiency and precise separation of counterions. However, ion-exchange membranes exhibit low ionic conductance and selectivity for ions with similar charges. In this study, we developed a novel ZIF-8 composite membrane with amine-modified nanochannels through an in situ PEI-assisted seeding and secondary growth method. An integral and uniform selective layer was formed, and the amine-modified nanochannels induced differential transport of Li+, Na+, K+, and Mg2+ via the dehydration-hydration process. The composite membrane possessed a lower energy barrier for Na+ transport (Ea = 13 kJ mol-1) compared to Mg2+ (Ea = 17 kJ mol-1), showing a Na+ flux of 3.7 × 10-8 mol·cm-2·s-1 and a Na+/Mg2+ permselectivity of 52 (∼60 times higher than the commercial membrane). The physicochemical and electrochemical properties of the composite membranes were systematically characterized, revealing the significant role of the Mg2+ layer in increasing Mg2+ repulsion and facilitating Na+ diffusion. Besides, DFT simulation and interaction energy calculation elucidated that a moderate binding energy and compensation effect between ions and nanochannels, which can be precisely regulated by PEI incorporation, are crucial for the favorable passage of Na+ while maintaining high Mg2+ rejection. The membrane also demonstrated performance stability during a 5-day test and maintained high selectivity across varying salinity and pH conditions. This work advances the development of efficient cation separation membranes for sustainable desalination and resource recovery.

Toward Personalized Cognitive Training in Older Adults: A Pilot Investigation of the Effects of Baseline Performance and Age on Cognitive Training Outcomes

BACKGROUND

Cognitive training holds potential as a non-pharmacological intervention to decrease cognitive symptoms associated with Alzheimer's disease (AD), but more research is needed to understand individual differences that may predict maximal training benefits.

OBJECTIVE

We conducted a pilot study using a six-month training regimen in healthy aging adults with no cognitive decline. We investigated the effects of baseline performance and age on training and transfer improvements.

METHODS

Out of 43 participants aged 65-84 years, 31 successfully completed cognitive training (BrainHQ) in one of three cognitive domains: processing speed (N = 13), inhibitory control (N = 9), or episodic memory (N = 9). We used standardized assessments to measure baseline performance and transfer effects.

RESULTS

All 31 participants improved on the cognitive training regimen and age was positively associated with training improvement (p = 0.039). The processing speed group improved significantly across many near- and far-transfer tasks. In the inhibitory control group, individuals with lower baseline performance improved more on inhibitory control and cognitive flexibility tasks. In the episodic memory group, older individuals improved most on a memory task while younger individuals improved most on an executive function far-transfer task.

CONCLUSIONS

Individual differences are predictive of cognitive training gains, and the impact of individual differences on training improvements is specific to the domain of training. We provide initial insight regarding how non-pharmacological interventions can be optimized to combat the onset of cognitive decline in older adults. With future research this work can inform the design of effective cognitive interventions for delaying cognitive decline in preclinical AD.