Low Growth Research Articles

Controlled epitaxy and patterned growth of one-dimensional crystals via surface treatment of two-dimensional templates

Mixed-dimensional van der Waals (vdW) heterostructures offer promising platforms for exploring interesting phenomena and functionalities. To exploit their full potential, precise epitaxial processes and well-defined heterointerfaces between different components are essential. Here, we control the growth of one-dimensional (1D) vdW microwires on hexagonal crystals via plasma treatment of the growth templates. AgCN serves as a model 1D system for examining the dependence of the nucleation and growth parameters on the surface treatment conditions and substrate types. The oxygen-plasma-treated transition metal dichalcogenides form step edges mediated by formation of surface metal oxides, leading to robust AgCN epitaxy with an enhanced nucleation density and low horizontal growth rates. Monte Carlo simulations reproduce the experimentally observed growth behaviors and unveil the crucial growth parameters, such as surface diffusivity. The plasma treatment results in distinct effects on graphite and hexagonal boron nitride templates, which undergo plasma-induced amorphization and deactivation of the AgCN vdW epitaxy. We achieve the selective growth of AgCN microwires on graphite using the deactivated vdW epitaxy. This study offers significant insights into the impact of surface treatment on 1D vdW epitaxy, opening avenues for controlled fabrication of mixed-dimensional vdW heterostructures.

Formulation and Cell Viability Assessment of Microparticles of Isolated Lactobacillus sp. with Alginate-Chitosan Solution

This study was performed to isolate the probiotic Lactobacillus sp. from dairy products available in Dhaka to form microparticles with isolated Lactobacillus probiotic bacteria and determine cell viability. Depending on their biological and physical traits and selective growth in MRS agar and MRS broth medium, the isolates were recognized as Lactobacillus spp. Major biochemical tests and growth at different temperatures were taken into account for the identification of the isolates. Low pH tolerance, homo- or hetero-fermentative activity, hydrolysis of arginine, and antibiotic susceptibility tests were conducted to assess probiotic activity. Among several isolates of Lactobacillus sp., four showed considerable tolerance to lower pH (pH 3.0) and growth at different temperatures (15 to 37°C). They were resistant to common antibiotics like penicillin (10µg), gentamicin (30µg), tetracycline (30µg), chloramphenicol (30µg), erythromycin (15µg) and streptomycin (30µg). The isolates were shown to have superior probiotic capabilities and may be employed as possible probiotic microorganisms after comparing all probiotic features evaluated in this experiment. The capacity of probiotic bacterial cells to survive when stored and in gastrointestinal transit is difficult to maintain. As a solution to these obstacles, microparticles were formulated with sodium alginate and chitosan. The cell viability check of the microparticles was continued for two weeks, and the response positively indicated increased stability. The results show promise for the encapsulation of the isolates. Jagannath University Journal of Life and Earth Sciences, 9(1): 69–80, 2023 (June)

Crop Monitoring System Using IOT

Currently, the low agricultural output is causing farmers to suffer. Low crop growth is primarily caused by knowledge of soil fertility and crop selection, even though proper crop selection is the primary booster key for enhancing agricultural yield by doing soil analysis and taking metrological elements into consideration. Farmers with limited experience in conventional farming are finding it difficult to make wise crop selection choices in the current environment. The low soil fertility is caused by the same crop being chosen for each seasonal cycle. The goal of this research is to use IoT devices to create an accurate and efficient system. Compared to the outdated manual laboratory testing procedures, which are subject to human errors, such a system is predictable. A crop's proper selection is mostly important in the agricultural field. As a contribution, we offer Smart Crop Selection (SCS), an IOT-based approach that is based on soil and metrological factor data. These variables include soil moisture content, temperature, and precipitation. Because these issues are not given as much care as they should, existing IoT-based systems are less efficient than our proposed model. Real-time sensory data is transmitted to Firebase cloud for analysis in the suggested model

Modelling the impact of wastewater flows and management practices on antimicrobial resistance in dairy farms

Dairy slurry is a major source of environmental contamination with antimicrobial resistant genes and bacteria. We developed mathematical models and conducted on-farm research to explore the impact of wastewater flows and management practices on antimicrobial resistance (AMR) in slurry. Temporal fluctuations in cephalosporin-resistant Escherichia coli were observed and attributed to farm activities, specifically the disposal of spent copper and zinc footbath into the slurry system. Our model revealed that resistance should be more frequently observed with relevant determinants encoded chromosomally rather than on plasmids, which was supported by reanalysis of sequenced genomes from the farm. Additionally, lower resistance levels were predicted in conditions with lower growth and higher death rates. The use of muck heap effluent for washing dirty channels did not explain the fluctuations in cephalosporin resistance. These results highlight farm-specific opportunities to reduce AMR pollution, beyond antibiotic use reduction, including careful disposal or recycling of waste antimicrobial metals.

Turkish Airlines: A New Era After the Pandemic

Turkish Airlines has been one of the fastest-growing airlines in the past two decades. An aggressive growth strategy combined with a favourable environment helped the company to become one of the major players in the world airline industry. The global COVID pandemic between 2020 and 2022 had an enormous negative effect on the airline industry worldwide. Turkish Airlines, which has been a fast-growing airline in recent years, has also been affected tremendously by this worldwide pandemic. In addition, there have been additional challenges faced by Turkish Airlines such as increased competition from other regional players, lower economic growth as well as emerging new regulations about fuel efficiency and emissions. All these factors have put Turkish Airlines at crossroad to make some critical strategic decisions. How should the company design its strategy in this new post-pandemic era? Can it continue to grow with its existing strategy? What are the limits and risks of the aggressive growth strategy it has been following? Is there a need for changing its strategy? What should be the priorities? Like many other airline companies, these decisions will shape the future as well as the nature of competition of the airline industry.

Dynamics of growing carbon nanotube interfaces probed by machine learning-enabled molecular simulations

Carbon nanotubes (CNTs), hollow cylinders of carbon, hold great promise for advanced technologies, provided their structure remains uniform throughout their length. Their growth takes place at high temperatures across a tube-catalyst interface. Structural defects formed during growth alter CNT properties. These defects are believed to form and heal at the tube-catalyst interface but an understanding of these mechanisms at the atomic-level is lacking. Here we present DeepCNT-22, a machine learning force field (MLFF) to drive molecular dynamics simulations through which we unveil the mechanisms of CNT formation, from nucleation to growth including defect formation and healing. We find the tube-catalyst interface to be highly dynamic, with large fluctuations in the chiral structure of the CNT-edge. This does not support continuous spiral growth as a general mechanism, instead, at these growth conditions, the growing tube edge exhibits significant configurational entropy. We demonstrate that defects form stochastically at the tube-catalyst interface, but under low growth rates and high temperatures, these heal before becoming incorporated in the tube wall, allowing CNTs to grow defect-free to seemingly unlimited lengths. These insights, not readily available through experiments, demonstrate the remarkable power of MLFF-driven simulations and fill long-standing gaps in our understanding of CNT growth mechanisms.

High-performance infrared photodetector based on InAs/GaAs submonolayer quantum dots grown at high temperature with a (2×4) surface reconstruction

We studied the impact of surface reconstruction on the performance of infrared photodetectors containing InAs/GaAs submonolayer quantum dots (SMLQDs) grown by molecular beam epitaxy. Adjusting the substrate temperature before InAs deposition allowed us to move between the conventional c(4×4) reconstruction of the GaAs(001) surface, observed at low growth temperatures, and the (2×4) reconstruction which can only be stabilized at higher sample temperatures than those commonly used to deposit InAs. Photodetectors based on SMLQDs grown on such a (2×4) surface reconstruction outperformed those grown on a c(4×4) reconstruction and provided specific detectivities as high as 8.3×1011 cm Hz1/2 W−1 at 12 K. This increase in performance is due to the nucleation of true two-dimensional InAs islands which are the building blocks of SMLQDs and can only form on a (2×4)-reconstructed GaAs(001) surface.

The Power and Roots of Aspirations

Abstract Aspirations have become a common theme in empirical economics studies but there is no unified understanding of the range of outcomes they influence, the factors that shape them, and how to measure them. We survey this growing literature. We argue that there is compelling evidence to consider aspirations as a useful lens to analyze human behavior and development outcomes, at the individual and aggregate levels, in poorer and richer countries. The empirical evidence aligns with the theory that high aspirations can lead individuals to achieve better educational, labor market, and other outcomes and can contribute to making countries more equal and prosperous. The empirical evidence also confirms that the mix of social and circumstantial factors shaping aspirations tends to hinder the aspirations of the disadvantaged—such as the poor, immigrants, and women—and can contribute to vicious circles of poverty, high inequality, low social mobility, and low growth. However, high aspirations should not be considered an end in themselves as they can backfire, with deleterious effects, if unmatched with opportunities. Further, we argue that definitional and measurement issues can affect the understanding of the topic and that studies should more explicitly describe their measures of aspirations to ensure that divergent underlying concepts are not mistaken.

How does technological progress affect low carbon economic growth? Evidence from regional heterogeneity in China.

The rapid economic development leads to excessive consumption of fossil energy, resulting in a large number of carbon emissions, which makes the sustainable development of China's economy and society face great challenges. Under the background of global warming and environmental deterioration, developing low-carbon economy has become an inevitable choice for China to change its development model and improve its international competitiveness. Technological progress is the first driving force to promote economic growth. However, the influence degree and mechanism of technological progress on the development of low-carbon economy are still unclear. Based on this, the paper proposes the concept of low-carbon GDP, which is used to measure the low-carbon economic development of 30 Chinese provinces. Then, the panel fixed effect model is used to study the effect degree and mechanism of technological progress on low-carbon GDP and the moderating effect of other factors on the relationship between them. The results show that, first, economically developed provinces and regions have higher per capita low-carbon GDP and low-carbon GDP index, but the speed and quality of low-carbon economic development are not necessarily higher. Second, technological progress can promote the growth of low-carbon GDP and make greater contributions to resources-poor regions. Third, improving local education can make technological progress more effective in low-carbon economic development. China needs to upgrade technological development by developing new and high-tech technologies, promoting new urbanization and strengthening education in order to promote low-carbon economic development.

Resistive switching and synaptic simulation behaviors of epitaxial ZnO/Nb-doped SrTiO3 heterojunction controlled by the substrate orientation

Zinc oxide (ZnO) films were grown epitaxially on Nb-doped SrTiO3 (NSTO) substrates with different orientations using laser pulse deposition to create the (112¯0)ZnO/(100)NSTO, (0002)ZnO/(110)NSTO and (0002)ZnO/(111)NSTO heterojunctions. Epitaxial ZnO films on the (100) NSTO had two orthorgonal domains, resembling the fourfold symmetry of the (100) NSTO substrate. This good matching between the grown ZnO film and NSTO substrate resulted in a lower growth rate, smoother and denser surface, and a higher density of interface defect states. The interface state density was approximately 4.4 × 1012 eV−1cm−2, which was notably higher than that of the other two heterojunctions. Electrical transport studies revealed that ZnO/(100)NSTO heterojunction demonstrated bipolar resistive switching and negative differential resistance (NDR) due to a higher density of donor interface states from contributions of oxygen vacancies, while both the ZnO/(110)NSTO and ZnO/(111)NSTO heterojunction exhibited typical rectifying behavior. The preliminary investigation into synaptic behaviors suggested that (112¯0) ZnO/(100)NSTO heterojunction holds significant potential in brain-inspired neuromorphic computing systems.

Effect of foaming characteristics of air entrained agents on mechanical properties and pore structures of cement-based materials in plateau mountainous regions

Concrete freeze-thaw damage is common in high-altitude regions. Adding an appropriate amount of air-entraining agents (AEA) can improve the flowability of fresh concrete and the frost resistance of hardened concrete, without significantly affecting concrete strength. However, the existing studies of the influence and mechanism of AEAs on concrete mainly focus on conventional environmental tests and simulated conditions, with less consideration to the various environmental factors caused by real altitude changes. In this study, five types of AEAs are utilized according to bubble shaking tests in two different altitude environments: Chengdu, Sichuan (altitude: 300 m; air pressure: 96.7 kPa), and Aba Prefecture, Sichuan (altitude: 3700 m; air pressure: 66.7 kPa). Physical and mechanical properties as well as pore structure tests are also conducted on AEA paste and concrete. The results show that the relationship between air bubble sizes and surface tension of AEA solutions is the closest, with larger bubble sizes, smaller bubble volumes, and poorer foaming properties observed at high-altitude regions. Adding an appropriate amount of AEA can improve concrete workability. In high-altitude and low-temperature regions, AEA concrete exhibits better slump retention. The addition of triterpenoid saponin AEA increases the proportion of small pores (0.5 μm–200 μm) in paste and concrete, with a lower growth rate observed at high altitudes compared to lower altitudes. Additionally, the average pore diameter and bubble spacing coefficient of hardened paste decrease, optimizing the pore structure. Triterpenoid saponin AEA is recommended for improving concrete performance in high-altitude environments, with a recommended dosage of 0.01 %.

Relationships between diameter growth and functional wood anatomy in Eucalyptus globulus clones

Aim of study: We aimed to 1) analyze the variability of wood hydraulic anatomical traits in 10 clones of E. globulus Labill. with different growth rates, and 2) determine whether the magnitude of diameter growth affects the relationships between anatomical variables and diameter at breast height (DBH). Area of study: 25-year-old common garden trial in Balcarce, Buenos Aires, Argentina. Material and methods: We measured vessel diameter and number per unit area in transverse histological sections of stem wood, and calculated the proportion of vessel lumens, vessel composition (S), and theoretical specific hydraulic conductivity (Ks) of 10 E. globulus clones of high (HG) and low (LG) mean growth rates (measured as DBH) under field conditions. Main results: There was a difference in the range of variability in hydraulic anatomy between HG and LG clones, with LG clones showing a wider range. HG clones had wood with larger and fewer vessels and higher S compared to LG clones, with similar Ks between both growth groups. No clear or strong trends were observed between wood anatomy and DBH within the HG and LG groups, but across all clones a high correlation (Spearman coefficient r; p<0.001) was observed between vessel number ‒ DBH (r= -0.68), and S ‒ DBH (r= 0.74). These correlations were driven by contrasting mean values of both growth groups. Research highlights: Commercial E. globulus clones present a relatively large variation in anatomical and hydraulic strategies. However, in contrast to what is postulated for various woody species, there was no clear relationship between theoretical hydraulic efficiency and individual diameter growth rate in the genotypes studied.

An investigation of the filtration performance and mechanism of oil-solid mixed particles on filter materials with different wettability

In the process of air filtration, filter materials may encounter oil-solid mixed particles from various sources such as industry and household, and the influence of filter material with different wettability on the filtration performance of oil-solid mixed particles has not been fully reported. The objective of this study was to prepare filter materials with varying wettability properties and investigate their filtration performance for oil-solid mixed particles with diverse oil contents. In this study, four filter materials were prepared using the impregnation method, exhibiting 0° (superoleophilic), 46° (oleophilic), 90° and 122° (oleophobic) oil contact angles. The oil-solid mixed particles with varying oil contents were loaded on the four different filter materials. The loading behavior of the filter materials was characterized from two aspects: macroscopic loading behavior (changes in pressure drop and DHC) and microscopic particle deposition behavior. The results demonstrated that, under the conditions of 25% and 50% oil content, the enhanced liquid bridge force between the oil-solid mixed particles on the oleophobic filter material facilitated the formation of a loose and porous cake layer structure compared with other filter materials, resulting in a lower growth rate of pressure drop and a higher dust holding capacity (DHC). However, in 75% and 100% oil content environments, the superoleophilic filter material owned a remarkably high affinity for oil particles compared with other filter materials, leading to the gradual formation of an oil film structure on the filter material, yielding lower the growth rate of pressure drop and higher DHC. These findings shed light on the mechanism of particle deposition under diverse filtration conditions and are applicable to the filtration of various oil-solid mixed particles over a wide range of oil contents.

Expanded Stability of Layered SnSe-PbSe Alloys and Evidence of Displacive Phase Transformation from Rocksalt in Heteroepitaxial Thin Films.

Bulk PbSnSe has a two-phase region, or miscibility gap, as the crystal changes from a van der Waals-bonded orthorhombic 2D layered structure in SnSe-rich compositions to the related 3D-bonded rocksalt structure in PbSe-rich compositions. This structural transition drives a large contrast in the electrical, optical, and thermal properties. We realize low temperature direct growth of epitaxial PbSnSe thin films on GaAs via molecular beam epitaxy using an in situ PbSe surface treatment and show a significantly reduced two-phase region by stabilizing the Pnma layered structure out to Pb0.45Sn0.55Se, beyond the bulk limit around Pb0.25Sn0.75Se at low temperatures. Pushing further, we directly access metastable two-phase films of layered and rocksalt grains that are nearly identical in composition around Pb0.50Sn0.50Se and entirely circumvent the miscibility gap. We present microstructural and compositional evidence for an incomplete displacive transformation from a rocksalt to layered structure in these films, which we speculate occurs during the sample cooling to room temperature after synthesis. In situ temperature-cycling experiments on a Pb0.58Sn0.42Se rocksalt film reproduce characteristic attributes of a displacive transition and show a modulation in electronic properties. We find well-defined orientation relationships between the phases formed and reveal unconventional strain relief mechanisms involved in the crystal structure transformation using transmission electron microscopy. Overall, our work adds a scalable thin film integration route to harness the dramatic contrast in material properties in PbSnSe across a potentially ultrafast crystalline-crystalline structural transition.

Examination of the role of mutualism in immune evasion.

Though the earliest stages of oncogenesis, post initiation, are not well understood, it is generally appreciated that a successful transition from a collection of dysregulated cells to an aggressive tumour requires complex ecological interactions between cancer cells and their environment. One key component of tumorigenesis is immune evasion. To investigate the interplay amongst the ecological behaviour of mutualism and immune evasion, we used a computational simulation framework. Sensitivity analyses of the growth of a virtual tumour implemented as a 2D-hexagonal lattice model suggests tumour survival depends on the interplay between growth rates, mutualism and immune evasion. In 60% of simulations, cancer clones with low growth rates, but exhibiting mutualism were able to evade the immune system and continue progressing suggesting that tumours with equivalent growth rates and no mutualism are more likely to be eliminated than tumours with mutualism. Tumours with faster growth rates showed a lower dependence upon mutualism for progression. Geostatistical analysis showed decreased spatial heterogeneity over time for polyclonal tumours with a high division rate. Overall, these results suggest that in slow growing tumours, mutualism is critical for early tumorigenesis.

JUE insight: Differences in rent growth by income from 1985 to 2021 and implications for inflation

Shelter is a large share of household expenditures and therefore has a large weight in inflation measurement. Because rich and poor households tend to make different housing and location choices, does the shelter component of inflation differ across the income distribution? I calculate rent growth for households in each quintile of the income distribution from 1985 to 2021 and find modestly lower rent growth for lower-income groups. However, because lower-income households spend a larger fraction of total expenditures on housing, I find little difference across groups in headline inflation. Therefore, different housing and location choices have not generated materially different shelter components of inflation across the income distribution.

The Evaluation of Impacts of Multi Factor Model on TTC Stock Price: a Case in Real Estate Industry in Vietnam

Objectives: The objective of this study is to analyze the impact of macroeconomic factors on the stock price of a real estate firm, specifically Thanh Cong TCC, in Vietnam from 2014 to 2020. The study aims to assess both positive and negative influences of five macroeconomic variables on stock prices and to understand the overall business health reflected by stock fluctuations. Methods: This study utilizes a data collection method involving statistics, analysis, synthesis, comparison, and quantitative analysis to generate qualitative comments and discussion. Econometric methods, particularly regression analysis, are employed to evaluate the quantitative results and assess the impact of macroeconomic factors on stock prices. Results: The quantitative research reveals several key findings. Firstly, the stock price of Thanh Cong TCC (Y) exhibits a negative correlation with the lending rate (R) and GDP growth, indicating that higher lending rates and lower GDP growth negatively impact stock prices. Conversely, there is a positive correlation between stock prices and the risk-free rate (Rf), consumer price index (CPI), and VNINDEX, suggesting that these factors positively influence stock prices. Furthermore, the study identifies GDP growth and lending rates as having the highest impact on firm stock prices. Conclusion: In conclusion, this study highlights the importance of considering macroeconomic factors in understanding stock price fluctuations in real estate firms in developing countries like Vietnam. The findings emphasize the significant impact of lending rates and GDP growth on stock prices, indicating their pivotal role in shaping the business health and overall economic conditions. By recognizing these influences, firms like Thanh Cong TCC can better navigate market dynamics and make informed strategic decisions to enhance their performance and resilience in the face of macroeconomic challenges.

Quantyfing the impact of the water security index on socio-economic development in EU27

The issue of environmental security in the context of sustainable development is a highly topical one, being intensively studied by specialists both in terms of its impact on biodiversity and on the protection of non-renewable resources, and in terms of its economic and social impact. The authors aim to quantify the impact of water security on economic and social development based on a new structural equation model and identify changes in the latent variable Water Security Index. (WSI), economic development (ED) and social development (SD) dynamics over the period 2000–2022 for the 27 EU Member States. The methodology is based on the use of structural equation systems and the use of the Independent-Samples Kruskal-Wallis Test to identify the influences of water security measures on economic and social indicators and to assess regional disparities of environmental policy development in relation to economic and social development. The research results will highlight the level of homogeneity of regional water security clusters in Europe and the influence of this approach on economic and social disparities. The results of the study highlight the significant correlation between population density, pollution levels and the costs associated with maintaining water quality. The study shows that high population density and high pollution levels disproportionately increase the financial burden of water quality management. In addition, the analysis highlights the social ramifications of neglecting the sustainability of water sources, particularly in regions experiencing low economic growth. In such scenarios, the negative social impact intensifies, highlighting the importance of sustainable practices. The results allow the formulation of the following public policies: Standardization of the national water quality management framework in line with the European framework; Establishment of organizations to monitor the safety of water sources and the health of the local population; Continuation of innovations in the field of water environment protection; Promotion of social responsibility towards the aquatic environment; Continuation of the process of improving water management governance. The results are useful for economic, environmental and social policy makers to optimise European sustainable development strategies.

A comparative study of tissue protein synthesis rates in an Antarctic, Harpagifer antarcticus and a temperate, Lipophrys pholis teleost

The affect of temperature on tissue protein synthesis rates has been reported in temperate and tropical, but not Antarctic fishes. Previous studies have generally demonstrated low growth rates in Antarctic fish species in comparison to temperate relatives and elevated levels of protein turnover. This study investigates how low temperatures effect tissue protein synthesis and hence tissue growth in a polar fish species. Groups of Antarctic, Harpagifer antarcticus and temperate, Lipophrys pholis, were acclimated to a range of overlapping water temperatures and protein synthesis was measure in white muscle (WM), liver and gastrointestinal tract (GIT). WM protein synthesis rates increased linearly with temperature in both species (H. antarcticus 0.16–0.23%.d−1, L. pholis, 0.31–0.76%.d−1), while liver (H. antarcticus 0.24–0.27%.d−1, L. pholis, 0.44–1.03%.d−1) and GIT were unaffected by temperature in H. antarcticus but increased non-linearly in L.pholis (H. antarcticus 0.22–0.26%.d−1, L. pholis, 0.40–0.86%.d−1). RNA to protein ratios were unaffected by temperature in H. antarcticus but increased weakly, in L.pholis WM and liver. In L.pholis, RNA translational efficiency increased significantly with temperature in all tissues, but only in liver in H. antarcticus. At the overlapping temperature of 3 °C, protein synthesis (WM 26%, Liver, 39%, GIT, 35%) and RNA translational efficiency (WM 273%, Liver, 271%, GIT, 300%) were significantly lower in H. antarcticus than L.pholis, while RNA to protein ratios were significantly higher (WM 270%, Liver 170%, GIT 186%). Tissue specific effects of temperature are detectable in both species. This study provides the first evidence, that tissue protein synthesis rates are constrained in Antarctic fishes.

Epitaxial trench refill of 4H-SiC by chlorinated chemistry

Trench epitaxy of 4H-SiC is investigated with the supersaturation of chlorinated chemistry at a growth temperature of 1550 °C. Coupled with a lower growth temperature than has been previously reported, the integrity of the 4H-SiC trenches is retained and minimal rounding effects of H2 annealing prior to growth are observed. The system gives different growth rates of materials on the various crystal faces of the trenches and can be used to improve the refilling process, resulting in the reduced void formation. The addition of excessive levels of HCl can suppress trench epitaxy by reducing the growth rate on the sidewalls of trenches in favor of growth on the surface. The processes demonstrated offer a scalable and reproducible method to fabricate SiC-based superjunction device structures for applications in high voltage power electronics.