Low Aggregation Research Articles

Evaluation and driving factors of ecological environment quality in the Tarim River basin based on remote sensing ecological index

Changes in the ecological environment quality (EEQ) in the main inland Tarim River Basin in China substantially impact the regional development. Indeed, comprehensive ecological environment measures have been implemented in the Tarim River Basin since 2000. In this context, the main objective of the present study was to investigate the spatiotemporal evolution of the EEQ and monitor the effectiveness of ecological restoration measures in the Tarim River Basin over the 2000–2020 period using remote sensing data. First, a Remote Sensing Ecological Index (RSEI) was constructed based on the Moderate Resolution Imaging Spectroradiometer remote sensing data. Second, the spatial distributions and factors of the RSEI were analyzed by using Moran’s Index and Geodetector. The results indicated that the overall RSEI values for the Tarim River Basin increased from 0.22 in 2000 to 0.25 in 2020. Moreover, the values for areas with poor EEQ decreased from 50.7% to 44.73%, while those with moderate EEQ increased from 11.45% to 16.91%. Therefore, the results demonstrated a slight overall improvement in the EEQ of the study area over the 2000–2020 period. On the other hand, the EEQ in the Tarim River Basin exhibited a significant spatial autocorrelation in the 2000–2020 period, with a relatively stable overall spatial distribution. Areas with high–high aggregation were distributed in the high-elevation mountainous areas in the western, northern, and southern parts of the study area. In contrast, areas with low–low aggregation were observed in the central and eastern low-elevation desert areas. The EEQ in the Tarim River Basin was driven by the interactions of several factors, including the normalized difference vegetation index, land surface moisture, land surface temperature, normalized differential build-up and bare soil index, and elevation. In particular, heat was the main driving factor that severely impacted the EEQ in the study area. Indeed, increase in the heat values could directly enhance meltwater runoff from glaciers in the basin, thereby resulting in short-term improvement in the basin EEQ. Furthermore, rapid urbanization from 2015 to 2020 resulted in a decrease in the average RSEI value of the Tarim River Basin by 0.1 over this period, consequently, the EEQ level decreased slightly. Briefly, the EEQ in the Tarim River Basin showed an overall increasing trend from 2000 to 2020, further demonstrating the effectiveness of a series of implemented ecological restoration measures in the Tarim River Basin over this period.

Effects of a Mechanically Interlocked Structure on Ionic Conductivity in Polyrotaxane-Based Polymer Electrolytes.

Polyrotaxane (PR) is a mechanically interlocked polymer (MIP) utilized as an electrolyte because of its distinctive property of dynamic molecular mobility. While numerous studies have concentrated on modifying external properties to decrease high crystallinity, few have explored the control of intrinsic properties. This study examines the crystalline properties and molecular mobility of PR-based electrolytes, along with their effects on ionic conductivity, by manipulating intrinsic properties. By systematically varying the inclusion ratio, we demonstrate that lower inclusion ratios lead to reduced crystallinity, enhancing molecular mobility. Consequently, 100PRE exhibits decreased crystallinity due to lower aggregation probabilities of α-cyclodextrins (α-CDs), longer T2 relaxation times (0.215 s), and higher ionic conductivity (3.4 × 10-3 S cm-1 at 25 °C).

Lipoic acid-locked reduction-responsive core-cross-linked micelles delivering paclitaxel for triple-negative breast cancer treatment

Most anti-tumor agents suffer from systemic non-specific distribution and low aggregation in tumors, which not only decreases the therapeutic efficacy, but also causes systemic toxic side effects in the treatments of tumors. In recent years, the rapid development of nanotechnology has brought new ideas for the application of anti-tumor drugs. Nanomedicines, such as liposomes and micelles, can improve drug targeting and prolong systemic circulation time to promote anti-tumor efficacy and reduce toxic side effects. However, conventional micelles bear the risk of instability and premature drug leaking in the blood circulation. We designed a reduction-responsive core-cross-linked micelle PTX@Fmoc-LA-PEG efficiently encapsulating Paclitaxel (PTX) via π-π stacking and hydrophobic interactions of Fmoc and PTX. Moreover, the micelle was further locked based on the cross-linking properties of the disulfide bonds formed by lipoic acid (LA). As expected, the core-cross-linked micelles PTX@Fmoc-LA-PEG remained stable in normal physiological environments, while restoring the normal drug release rate of micelles under the highly reducing environment due to LA unlocking. The blank micelles (Fmoc-LA-PEG) exhibited excellent biocompatibility, while the drug-loaded micelles (PTX@Fmoc-LA-PEG) displayed a remarkable anti-tumor effect in vitro and in vivo experiments. These results suggested that core-cross-linked micelles PTX@Fmoc-LA-PEG have great potential to improve the targeting and stability of anti-tumor drugs.

Engineering and physicochemical characterization of a novel, stable, symmetric bispecific antibody with dual target-binding using a common light chain.

Bispecific antibodies (BsAbs) have emerged as a major class of antibody therapeutics owing to their substantial potential in disease treatment. While several BsAbs have been successfully approved in recent years, ongoing development efforts continue to focus on optimizing various BsAbs tailored to particular antigens and action mechanisms, aiming to achieve favorable physicochemical properties. BsAbs generally encounter challenges due to their unfavorable physicochemical characteristics and poor manufacturing efficiencies, highlighting the need for optimization to achieve reliable productivity and developability. Herein, we describe the development of a novel symmetric BsAb, REGULGENT™ (N-term/C-term), comprising two Fab domains, using a common light chain. The heavy chain fragment encoded two antigen-binding determinants in one chain. The design and production of REGULGENT™ (N-term/C-term) are simple owing to the use of the same light chain, which does not induce heavy and light chain mispairing, frequently observed with the asymmetric BsAb format. REGULGENT™ (N-term/C-term) exhibited high expression and low aggregation characteristics during cell culture and stress treatment under low pH conditions. Differential scanning calorimetric data indicated that REGULGENT™ molecules had high conformational stability, similar to that of stabilized monoclonal antibodies. Surface plasmon resonance data showed that REGULGENT™ (N-term/C-term) could bind to two antigens simultaneously and exhibited a high affinity for two antigens. In summary, the symmetric BsAb format of REGULGENT™ confers its desirable IgG-like physicochemical properties, thus making it an excellent candidate for commercial development. The findings demonstrate a novel BsAb with substantial development potential for clinical applications.

Landscape metrics as predictors of water-related ecosystem services: Insights from hydrological modeling and data-based approaches applied on the Arno River Basin, Italy

The study addresses the challenge of integrating complex landscape-hydrological interactions into predictive models for improved water resource management. The aim is to investigate the effectiveness of landscape metrics—quantitative indices measuring landscape composition and configuration—as predictors of WES in the Arno River Basin, Italy. Utilizing two hydrological models alongside a random forest algorithm, we assessed spatial and temporal variations in water yield, runoff, and groundwater recharge. The findings indicate that landscape metrics derived from high-resolution land use data significantly impact WES outcomes. Specifically, the models demonstrated average landscape metric importances of 16.8 % for spatial and 17.8 % for temporal predictions concerning runoff. For water yield, these averages were 32.9 % spatially and 43.5 % temporally, while groundwater modeling showed importances of 14.09 % spatially and 33.8 % temporally. Key landscape metrics identified include the core area index for broad-leaved forests and the perimeter-to-area ratio for non-irrigated agricultural areas as critical spatial and temporal predictors of water yield and groundwater recharge. Thresholds were observed, indicating landscape configurations that minimize hydrological variability. For instance, runoff variation is minimal when the landscape exhibits high forest fragmentation (over 1000 coniferous patches), low aggregation (aggregation index <75), and reduced connectivity (cohesion index under 80). Similarly, groundwater variation is minimized with decreased boundary length of vegetation patches (perimeter-to-area ratio <0.8), agricultural lands (perimeter-to-area ratio under 1), and the presence of low core agricultural areas (core area index above 8). The identified thresholds could inform land-use policies, such as targeted afforestation or crop diversification strategies, to optimize WES provision.

Synergistic Schottky contacts & diatomic doping in Cr/P-MoS2@Ti3C2Tx with boosted energy storage performance

Molybdenum disulfide (MoS2), despite its promising attributes, suffers from low conductivity and aggregation. Herein, we introduce a novel approach that integrates Schottky contacts with Cr/P diatomic doping in MoS2@Ti3C2Tx, significantly enhancing its performance. The Schottky contacts effectively suppress aggregation and accelerate interfacial charge transfer, while Cr/P doping boosts conductivity, active sites, and stability. As a result, the Cr/P-MoS2@Ti3C2Tx electrode exhibits a specific capacitance of 650 F g-1 at 1 A g-1, which is fourfold higher than that of pristine MoS2. When assembled into an asymmetric supercapacitor (Cr/P-MoS2@Ti3C2Tx//AC ASC), the device achieves a peak energy density of 32 Wh kg-1 at 303 W kg-1, maintaining 85% capacitance retention after 10,000 cycles with an impressive coulombic efficiency of 97%. Furthermore, the density functional theory (DFT) calculations validate the beneficial effects of Schottky contacts and diatomic doping on the improved energy storage performance of Cr/P-MoS2@Ti3C2Tx. This work demonstrates the promising potential of the material for applications in high-performance supercapacitors (SCs).

The Uses of Lightweight Material in Civil Engineering : A Review

A lightweight aggregate (LWA) is a group of aggregates with a relative density lower than normal density aggregates (natural sand, gravel, and crushed stone), sometimes referred to as low density aggregate. It is utilized for its reduced weight and exceptional qualities in sound reduction, fire resistance, insulation, and geotechnical applications LWA, or lightweight aggregate, is a cutting-edge construction material that is employed to decrease the overall weight of tall structures. Despite being lighter, it possesses a strength that is comparable to that of regular concrete. In recent times, there has been a significant surge in the use of lightweight aggregate in the field of building, mostly because of its exceptional performance in seismic situations. In addition, substituting natural aggregate with other industrial by-products and trash enables us to minimize the adverse environmental consequences. Laser wavelength ablation (LWA) has also been employed to address a wide range of geotechnical engineering challenges, including the transformation of soft and unstable soil into a suitable and usable property. Lightweight fillings have a weight that is around 50% less than fills made using typical materials. The load reduction, along with the high internal friction angle of the lightweight aggregate, can decrease vertical and lateral pressures by almost 50%, potentially resulting in less settling. This literature study examines the use of lightweight materials, including LECA, Bonza, and Thermostone, in geotechnical engineering applications. The results demonstrate a significant emphasis on improving slope stability and minimizing stresses on susceptible soils. Nevertheless, several knowledge gaps exist regarding the efficacy of these materials under challenging conditions and when subjected to dynamic loads. A growing inclination towards using these lightweight aggregates is observed because of their advantageous environmental and mechanical properties. Further investigation is needed to examine the extended-term performance and interactions of these materials with different soil types in order to enhance their performance in diverse geotechnical situations.

Strain-Dependent Adhesion Variations of Shouchella clausii Isolated from Healthy Human Volunteers: A Study on Cell Surface Properties and Potential Probiotic Benefits.

The probiotic potential of Shouchella clausii is widely recognized, but little is known about its adhesive properties. Hence, this study aims to investigate the adhesion potential and cell surface properties of four human-origin S. clausii strains (B619/R, B603/Nb, B106, and B637/Nm). We evaluated epithelial adhesion, Extracellular Matrix (ECM) binding, aggregation ability, and cell surface hydrophobicity and used genome analysis for validation. Our results demonstrate that adhesion capability is a strain-specific attribute, with significant variations observed among the four strains. B619/R, B603/Nb, and B106 displayed stronger adhesion properties than B637/Nm. Supplementary adhesion assays showed that B637/Nm displayed high hydrophobicity, significant auto-aggregation, and significant mucin-binding abilities. Conversely, B619/R, B603/Nb, and B106 had mildly hydrophobic surfaces and low aggregation abilities. Genome annotation revealed the presence of various adhesion proteins in four strains. Notably, the reduced adhesion potential of B637/Nm was supported by the absence of the cell wall surface anchor family protein (LPxTG motif), which is crucial for interactions with intestinal epithelial cells or mucus components. Further, docking studies provided insights into the interaction of adhesion proteins with gut mucins. These findings contribute to a better understanding of how S. clausii strains interact with the gut environment, facilitating the development of probiotic formulations tailored for improved gut health and well-being.

Fabrication of low conductivity and high strength MgO-MgAl2O4 aggregates with sub-micron pore structure

Lightweight MgO-MgAl2O4 refractory aggregates were fabricated by using fine MgO and spherical Al(OH)3 powders as starting materials. The evolutions of microstructure and pores and their effects on the properties of the specimens were investigated. During heating process, MgO crystallites diffused into the formed Al2O3 pseudomorph, producing sub-micron intra-particle pores in both MgAl2O4 cores and MgO matrix. Besides, larger inter-particle pores between the MgAl2O4 cores and MgO matrix were occurred, attributing to the Kirkendall effect resulting from in-situ spinalization. As MgO content increased from 50 wt% to 80 wt%, due to reduction of the number of the porous MgAl2O4 cores, the inter-particle pores caused by Kirkendall effect decreased sharply in both number and size, while no obvious changes occurred in the intra-particle pores as the porous MgO matrix amount increased simultaneously. The decrease of large inter-particle pores caused obvious improvement in strength but slight increase in thermal conductivity. With a further increase of MgO to 90 wt%, as the number of the porous MgAl2O4 cores reduced further and the MgO matrix densification improved obviously, intra-particle pores and thermal insulation performance reduced significantly. The specimen with 80 wt% MgO showed the best performance, with a median pore diameter of 0.26 μm, apparent porosity of 36.0 %, flexural strength of 23.9 MPa, and thermal conductivity of 2.1 W/(m·K) at 500 °C.

Marginal Aggregates: The Role of Clays.

Clays are components in the fine portion of aggregates, less than 75 microns in size (micro-fines), which are usually washed away when producing coarse or fine (manufactured sand) aggregates in quarries. When marginal sources of aggregates are being used, the content of this washed portion can be quite high, and there is an incentive to keep as much of it in the aggregate, including the clays. The present paper presents a comprehensive treatment of the role of clays in terms of the characterization of their composition and quantification of their effects on the rheological and mechanical properties of cementitious systems, as well as the means to mitigate deleterious influences. It is shown that the strategy for neutralizing the effect of micro-fines containing clays on increased water demand in concrete can be quantified in terms of the combination of their content in concrete and their nature as characterized by the methylene blue value (MBV); this is a more rational approach to considering their influence than their content in specific aggregates as specified in standards. The effect of low and medium MBV aggregates on the water requirement can be neutralized by lignosulfonates when their content in the concrete is below a threshold value of about 150 kg/m3; polycarboxylates (PC) are required at higher contents; for high MBV aggregates, a combination of PC and clay mitigating admixture (CMA) is required. It is also demonstrated that with proper treatment, such micro-fines can be turned into useful fillers, enhancing the strength of concrete and thus also serving as a means for reducing cement content.

High entropy Prussian Blue Analogues assisted by reduced graphene oxide for enhancing the lifespan of Sodium-ion batteries

In recent years, Prussian blue analogues (PBAs) have been regarded as one of the most promising cathode materials for Sodium-ion batteries (SIBs) due to their open structure, low cost, and high theoretical capacity. However, the problem of capacity degradation caused by phase transitions during the charge/discharge process has so far limited the applicability of PBAs. While the high entropy strategy can alleviate capacity decay induced by phase transitions, challenges such as low conductivity, material aggregation, and severe interface reactions between electrode materials and electrolytes still persist. Therefore, we used a simple and scalable one-step co-precipitation method to grow high entropy Prussian blue analogues (HEPBA) on reduced graphene oxide (rGO) to address these problems. The rGO not only inhibits material agglomeration but also separates the electrolyte from the electrode material to prevent severe interface reactions. Meanwhile, the Warburg impedance is reduced and the Na+ diffusion performance is improved. When high entropy Prussian blue grown on an rGO matrix (HEPBA@rGO) is utilized as the cathode in a half-cell, it exhibits high discharge specific capacity (115.2 mAh g−1 at 100 mA g−1), long cycling stability (retaining 84.6 mAh g−1 after 1000 cycles), and good rate capability (62 mAh g−1 at 15 C). The full battery with HEPBA@rGO as the cathode and hard carbon as the anode has a high specific discharge capacity (100.12 mAh g−1 at 100 mA g−1), good stability (capacity retention rate of 81 % after 150 charge/discharge cycles), and good rate performance (72.5 mAh g−1 at 5 C). This study provides valuable insights for the development of SIBs.

Population structure, spatial aggregation, and sampling plan for the Texas citrus mite, Eutetranychus banksi (Acari: Tetranychidae) on citrus.

Eutetranychus banksi (McGregor) (Acari: Tetranychidae) is an invasive spider mite native to the Americas. In 2013 it invaded the main citrus-growing area in Spain producing significant damage and requiring chemical treatments. This work examines its population structure, spatial distribution and presents a sampling plan, which will assist in developing an integrated pest management (IPM) strategy. There were differences in the population structure on fruits and leaves, as well as between leaves from different flushes with fluctuations over time correlated with variations in sex ratio. No differences in aggregation at the different plant strata were found; however, immature stages showed a higher aggregation than adults, with females being the sex with the lowest aggregation. There was a high correlation between E. banksi motile forms and adult females with the total population, thus both were used as reference stages to develop sampling plans. We recommend binomial sampling of 100 leaves for female monitoring, sampling two leaves per tree on 25 trees per transect regularly spaced along two diagonal transects, the first oriented northeast to southwest and the second northwest to southeast. To be more accurate, it is possible to survey the presence/absence of motile forms. In this case, four leaves per tree in 50 trees per transect should be monitored. This study has resulted in the first sampling plan for E. banksi, one of the most damaging citrus mite species described so far. The binomial sampling plan involves monitoring reference developmental stages, as well as a reasonable sample size that makes it applicable in field sampling for decisions making based on a future intervention threshold. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Antioxidant and anti-cancer potentials of Ag green-synthesized and encapsulated olive leaves particles on HCT-116 cells

Water extracts (OLE), whey protein encapsulated extracts (OLE/WPNs), and silver nanoparticles (OLE/Ag-NPs) were prepared from olive leaves of Manzenllie and Picual varieties. These preparations were characterized, and their antioxidant and biological activities on Vero and HCT-116 colorectal cells were assessed. The mechanism of action of the preparations was studied through tumor necrosis factor-α (TNF-α) and cytochrome C oxidase (Cox1) gene expression. OLE/Ag-NPs showed smaller particle sizes (14.23–15.53 nm) than OLE/WPNs (229.83–310.67 nm) and demonstrated lower aggregation due to their high Ƹ-potential of −24.86 to −27.90 mV. None of the preparations affected the viability of Vero cells (IC50 = 192.19–421.01 μg/mL), but they showed cytotoxic effects on HCT-116 cells (IC50 = 50.76–196.54 μg/mL), particularly OLE/WPNs. Moreover, the preparations from the Picual variety (OLE, OLE/WPNs, and OLE/Ag-NPs) showed regulatory effects against colon cancer on treated HCT-116 cells by upregulating Cox1 expression and downregulating TNF-α expression. Consequently, OLE/WPNs and OLE/Ag-NPs could be promising for industrial applications with potential health benefits.

Effect of the Hofmeister series anion salts on the ice recrystallization inhibition activity of tamarind seed polysaccharide

Tamarind seed polysaccharide (TSP) has been identified as an ice recrystallization inhibition (IRI)-active polysaccharide with potential applications in food cryoprotection. In this study, the IRI performance of TSP was investigated using the splat assay in the presence of different salts containing Hofmeister series anions (Na2SO4, NaH2PO4, NaCl, and NaNO3). The results showed that the IRI activity of TSP in different salt solutions depended on the type of ion present, in agreement with the reverse Hofmeister anion sequence: NO3− > Cl− > H2PO4− > SO42−. It was discovered that the Hofmeister series anion salts modulate the IRI activity of TSP by inducing changes in the aggregation and hydration properties of polysaccharides. In particular, TSP exhibited greater IRI activity when characterized by a lower aggregation and higher hydration degree in the presence of chaotropic ions. These findings highlight the influence of additives present in cryopreservation media and contribute to a fundamental understanding of the mechanism underlying the differential influence on the performance of IRI-active polysaccharides.

Glutathione-modified hyaluronic acid nanoparticles for the targeted delivery of sulfasalazine to neuroblastoma

A new nanoparticulate system based on hyaluronic acid for targeted delivery of sulfasalazine (SSA) to neuroblastoma was synthetized and characterized. The SSA-containing nanoparticles were obtained by nanoprecipitation and then surface-modified with PEG chains and glutathione using EDC/NHS chemistry. The resulting hydrogel nanospheres had a hydrodynamic diameter of about 165 nm and were colloidally stable. AFM and cryo-TEM images confirmed their spherical shape, nanometer size and low aggregation tendency. SSA was effectively encapsulated in the polymer matrix and released from the nanoparticles in a controlled manner. Bioassays showed that our nanoparticles were non-hemolytic, efficiently taken up by neuroblastoma cells and, compared to free SSA, showed superior cytotoxicity against SH-SY5Yneuroblastoma cells at low concentrations. Both the release profile and biological studies indicate the high potential of our delivery system in neuroblastoma therapy.

Effects of the maternal social environment on the mating signals and mate preferences of adult offspring in Enchenopa treehoppers.

Much is known about how the maternal environment can shape offspring traits via intergenerational effects. It is less clear, however, whether such effects may reach adult offspring sexual traits, with potential consequences for sexual selection and speciation. Here, we report effects of adult female aggregation density on the mating signals and mate preferences of their offspring in an insect that communicates via plant-borne vibrational signals. We experimentally manipulated the density of aggregations experienced by egg-laying mothers, reared the offspring in standard densities, and tested for corresponding differences in their signals and preferences. We detected a strong effect in male signals, with sons of mothers that experienced low aggregation density signalling more. We also detected a weak effect on female mate preferences, with daughters of mothers that experienced low aggregation density being less selective. These adjustments may help males and females find mates and secure matings in low densities, if the conditions they encounter correspond to those their mothers experienced. Our results thus extend theory regarding adjustments to the social environment to the scale of intergenerational effects, with maternal social environments influencing the expression of the sexual traits of adult offspring.

Spatial distribution and pedigree age of intangible cultural heritage along the Grand Canal of China

Intangible cultural heritage is the carrier of national memory and a historical witness. Exploring the spatial distribution and chronological evolution of intangible cultural heritage is of great significance to understand the cultural integrity and historical continuity. Taking the intangible cultural heritage along the Grand Canal as an example, this study carries out spatial deconstruction based on the extent of the spread of intangible cultural heritage and reveales the aggregation pattern through spatial autocorrelation analysis. Then, the historical process and the spatial center of gravity are shown through an evolution tree model. The influencing factors are illustrated via the methods of Geodetector and qualitative analysis. The results are as follows: (1) The two ends of the canal exhibit obvious advantages in the number of intangible cultural heritage items; however, the existence of a spatial mismatch at the city–county level makes the southern endpoint occupy a dominant position. (2) Although there is a high–high aggregation pattern along the whole canal, 29.82% of the counties are distributed widely with low–low aggregation. (3) The spatial center of intangible cultural heritage items from different historical periods generally presents a changing path from north to south and returning north. (4) Intangible cultural heritage items are mainly distributed in areas with a prosperous culture, a high level of economic development, and strong policy and financial support from government. Changes in the natural environment, population migration, economic development, war disasters, and canal shipping have profound impacts over time. This study provides a new idea for the methodological advancement of spatial distribution of intangible cultural heritage, as well as studies on local cultural identity and regional consistency.

Study on Interprovincial Equity and the Decoupling of Carbon Emissions in the Construction Industry—A Case Study in China

Interprovincial disparities in carbon emissions from the construction industry (CECI) are an important challenge for future emissions reductions. Based on the CECI data of 30 provinces in China from 2010 to 2020, the interprovincial equity and decoupling of CECI were examined in this study. The conclusions are as follows: (1): The main CECI growth regions were the eastern Bohai Rim region and the Pearl River Delta region. Heilongjiang basically achieved a CECI carbon peak in 2016. (2) The three northeastern provinces and western provinces were the main high–high and low–low aggregation areas, respectively. The greatest degree of inequality was found in the western provinces. The inequality between the eastern and western areas was the largest, while the inequality between the central and western areas was the smallest. The inequality in CECI in the north–south region decreased year by year. (3) The decoupling status of Shandong and some western provinces has significantly worsened, while the decoupling status of Sichuan, Yunnan, and some eastern developed provinces has been improving. These conclusions will contribute to the improvement of regional emission reduction strategies.

Occupational choice, human capital and financial constraints

AbstractWe study the aggregate productivity effects of firm‐level financial frictions. Credit constraints affect not only production decisions but also household‐level schooling decisions. In turn, entrepreneurial schooling decisions impact firm‐level productivities, whose cross‐sectional distribution becomes endogenous. In anticipation of future constraints, entrepreneurs underinvest in schooling early in life. Frictions lower aggregate productivity because talent is misallocated across occupations and capital is misallocated across firms. Firm‐level productivities are also lower due to schooling distortions. These effects combined account for between 36% and 68% of the US–India aggregate productivity difference. Schooling distortions are the major source of aggregate productivity differences.

Effect of soil management on carbon stock and soil aggregation in an area of natural regeneration and surrounding systems in the Atlantic Forest biome

This study aimed to quantify total organic carbon (TOC), carbon of humic substances (HS), and their stocks and evaluate the soil structural stability of areas with different uses under sandy loam soil texture. Soil samples were collected from managed areas and a reference area: Permanent Pasture (PP), No-Till (NT), Private Natural Heritage Reserve in the process of natural regeneration (PNHR) and Native Forest (FN). Dry mass analysis, carbon stock quantification, chemical fractionation of soil organic matter and soil aggregation were carried out. The NF area had the highest deposition of litter mass (ML). The PP and NT areas had the highest bulk density (Bd). TOC and Stock-C contents were higher in PNHR, followed by NF, and stratification index (STRATI) was also higher in the regeneration area. The NT, PNHR, and NF areas had a higher proportion of carbon fulvic acid fraction (C-FA) than carbon humic acid fraction (C-HA), but the fraction with the highest representation in all areas was carbon humin fraction (C-HUM). The PP, PNHR, and NF areas obtained the best aggregate stability indicators, as well as a higher proportion of macroaggregates, with the NT area having low aggregate stability. Recovery of C contents was observed in recent years in the area of PNHR, leading to a greater storage of C, which shows a quantitative recovery of C in the soil in this area after four years of natural regeneration. Furthermore, the PP and NT areas present a lower capacity for C sequestration, mainly due to the management conditions. Keywords: aggregate stability, climate change, crop production, soil quality.