Stock Production Research Articles

Impacts of prescribed fire and mechanical shredding of aboveground vegetation for fire prevention on ecosystem properties, structure, functions and overall multi-functionality of a semi-arid pine forest

Ecosystem multi-functionality is a key concept when measured to protect forests from natural and anthropogenic disturbances, such as fire prevention techniques, must be adopted. Despite this importance, scarce studies have analysed the impacts of prescribed burning and aboveground vegetation management on ecosystem functions and overall multi-functionality. To fill this gap, this study has evaluated the changes in some ecosystem properties and structure (associated with soil characteristics and plant diversity, respectively), in important forest functions, and the overall ecosystem multi-functionality in a Mediterranean pine forest of Castilla La Mancha (Central Eastern Spain) under three site conditions: (i) undisturbed ecosystem; (ii) forest subjected to mechanical shredding of aboveground vegetation (hereafter “AVMS”); and (iii) forest treated as above and then with prescribed fire (“AVMS + PF”). The results of the study have shown that neither the PF nor AVMS have significantly modified the structure, properties and functions as well as the overall multi-functionality of the forest ecosystem. These slight impacts of the treatments are due to the low fire severity of the prescribed burning and the long time elapsed from the vegetation management. Among the studied ecosystem functions, organic matter decomposition (driven by the enzymatic activities and soil basal respiration), water cycle (influenced by soil water content and water infiltration), carbon stock (linked to soil organic matter) and biomass production decreased, when species richness and plant diversity increased. The study is useful to indicate the feasibility of forest management actions for fire prevention in delicate forest ecosystems of the Mediterranean environments.

Revolutionising Skincare Through Airtificial Intelligence

Abstract: Background: Over the last 10years there has been a drastic shift in the development of computer-based systems, artificial intelligence, algorithms and technology in the world of dermatology be it cosmetic or even retail production of products sold to customers with high-tech technology and innovative means to build their client base through customer delight. Artificial Intelligence is particularly helpful in recognizing the type of skin customers have and suggesting solutions which help customers pick from the range of options given to them. Most e-commerce platforms have begun using such AI driven soft wear to help customers while they are in the comfort of their homes to choose from a range of cosmetic options right from lipsticks, concealers, foundation, eyeshadows, shades of tins, serums etc. Given that every person has a different skin type, these applications ensure 100 percent personalized suggestions. This new trend is sending shock waves across the retail sector around the world attracting a massive customer base to adapting to AI Derma logy and retail. The intelligent software used by sever companies not only benefits the customer, but also helps companies with their operational efficiency as they can use AI algorithms to predict and forecast the inventory to help reduce over production and excessive stock production minimizing product wastage and improving sustainably.AI is booming in both clinical diagnosis as well as giant companies such as Loreal and Olay who are dedicated to providing customers with advanced tools like skin analyzers or apps based on predefined rules which help AI-powered tools analyze skin conditions, age, and personal skincare history to provide highly personalized product recommendations. In clinical diagnosis AI offers valuable insight to the patient’s skin and condition be it cancer or other skin diseases making judgments to assist the doctors and dermatologist in making informed decisions regarding the line of treatment for the patient in question. This includes screening, diagnosis, treatments and predictions of the treatment outcomes. These new innovative and robust AI systems leaving customers feeling confident and have not begun relying on AI driven treatments and procedures

Carbon stock assessment of a reforestation site within Mt. Arayat protected landscape, Pampanga, Philippines

The Philippines has very few studies in terms of biomass production and carbon stocks in reforestation sites and the level of emission that has been avoided due to forest protection activities. Most of carbon stock estimates being used in the country are based on secondary data or studies in other countries using the same species. The study aimed to provide a reliable assessment on the contribution of reforestation sites in biomass production and carbon stocks and the potential of these plantation to contribute to the climate change mitigation efforts in the Philippines. The guideline prepared by the Philippines’ Department of Environment and Natural Resources – Forest Management Bureau (DENR-FMB) in 2021 on Forest Resources Assessment (FRA) which follows the manual of Food and Agriculture Organization of the United Nations (FAO) Forestry Department in conducting FRA was used during data collection. A tract was established in the southern portion of the reforestation site wherein the species planted in 2012 are already very prominent and their diameter at breast height (DBH) and total height were measured and their corresponding wood specific gravity were taken into account. Carbon stocks were estimated using Chave et al.’s and Brown’s allometric equations. The estimated carbon stocks using Chave et al.’s formula is 542.3 tC/ha while the estimated carbon stock using Brown’s formula is 2001.6 tC/ha. The results of computation using Brown’s equation are considerably higher than the results using Chave et al.’s equation considering that Brown’s equation only took into consideration the DBH of trees while Chave et al.’s equation included the height and wood specific gravity of each species. The study demonstrated how important our forests in terms of their roles as carbon sinks and therefore contribute to our country’s efforts in climate change mitigation.

Clean Energy and Long Run Dynamics of Output, Labor and Capital Stock: Evidence from China

Clean energy has sparked the importance of a sustainable environment and economic production in China. The concerns of climate and global warming can be solved with the adoption of clean energy. This study investigates the potential long-run connection amid economic production, labor, and capital stock with clean energy employing data from the years 1990-2020 in China. The combination of long-run estimates with Granger causalit678y has been employed. The observed output indicates that there is a long-run connection among these variables in an equilibrium sense. Also, changes in clean energy are significant in explaining changes in economic production. The outputs of the causality test corroborate that clean energy is causing economic production. The estimated elasticity of clean energy with respect to production is statistically significant in the long run. The findings imply that the development of new energy technologies for clean energy should be incorporated into the energy mix to balance the supply-demand gap.

Managing Complexities in Giant Freshwater Prawn Breeding Facilities in Perak, Malaysia: A Case Study

Malaysia's aquaculture industry has seen significant growth in recent years, with the giant freshwater prawn (Macrobrachium rosenbergii) emerging as a key species of economic importance. This study examines the intricate challenges faced by hatchery owners’ breeding facilities in Manjung, Perak, Malaysia as they strive to maintain and improve the brood stock production of this valuable crustacean. The research focuses on multifaceted, operational aspects of managing giant freshwater prawn hatcheries. Through a combination of field studies guided by qualitative methodology, the identification of primary obstacles encountered at Manjung breeding facilities was evaluated via current management practices. The findings revealed that hatchery owners lack adequate managerial skills in handling operational matters such as budgeting, labor utilization, utilities, marketing, and networking. The most critical factor was cost-effective sourcing of healthy, brood stock supply from local fishermen. Furthermore, the research underscores the importance of genetic diversity in broodstock populations as hatcheries struggle with inbreeding depression, necessitating the development of more robust breeding programs. From the socio-economic standpoint, a holistic approach to addressing these issues, emphasizes the need for increased collaboration between research institutions, government agencies, and private sector stakeholders. The study provided a comprehensive overview of the complexities inherent in managing giant freshwater prawn breeding facilities in Malaysia. By identifying key challenges and potential solutions, it aims to contribute to the sustainable development of this vital sector of Malaysia's aquaculture industry. The findings have implications for policy-making, industry practices, and future research directions in the field of freshwater prawn aquaculture and food security agenda.????????????????

Numerical methods for optimizing logistics systems in the process of inventory management

Scientists have always faced the task of evaluating the effectiveness of the functioning of complex systems, which unambiguously include logistics systems of transport (water, air, rail, automobile and their combinations) and stocks of products (goods), which (stocks of goods) are in static (warehouses) and dynamic (transport) states over time. A huge amount of theoretical material has been accumulated in this field of knowledge, which has been repeatedly tested and successfully applied, especially in relation to logistics systems. However, as is known, on the basis of an efficiency assessment, similar systems are compared, the operation of the systems is promptly evaluated, the system's compliance with its purpose is checked, the presence or absence of targeted targeting is found out, etc. Hence, the relevance of the mathematical apparatus (numerical methods) for optimizing stocks of products (goods) is determined as a calculation for reasoned decision-making on effective inventory management using transport and storage capacities on an economic basis: the objective function is to minimize costs. Cost reduction in the processes of functioning of logistics systems due to the action of two basic laws – the law of saving time and the law of conservation of energy is one of the main modern directions for increasing their efficiency as complex systems [1-5]. Therefore, the optimization of logistics systems according to the criterion of costs (losses) in the processes of their functioning is defined as the formulation of the research task. The aim of the work is to develop the application of numerical methods for optimizing logistics systems in the process of inventory management. The novelty consists in the application of numerical methods and the calculated ratios obtained, which can be used in the practice of the logistics system of water, air, rail and road transport for inventory management by optimizing the determined losses (costs). The result consists in the developed method of studying theoretically calculated losses occurring in the processes of functioning of logistics systems of all types of transport and their combinations (hereinafter transport). The theoretical significance of the results obtained is the development of the application of numerical methods for optimizing logistics systems in the process of inventory management, including: a set of factors and criteria for optimizing logistics processes; a method for modeling and optimizing the processes of functioning of logistics transport systems; a method for analyzing losses in the processes of functioning of logistics transport systems. These theoretical provisions make it possible to optimize the processes of functioning of logistics transport systems and, ultimately, to increase the efficiency of providing consumers, which is of important socio-economic importance.

Time varying M with starvation mortality in a state-space stock assessment model: Part 2: Atlantic cod (Gadus morhua) on the southern Grand Bank of Newfoundland

State-space models are now a common tool for modeling time-varying ecological phenomena. This extends to state-space stock assessment models (SSAMs), recognized as pivotal components within the evolving landscape of next-generation stock assessment methodologies. Though methods are rapidly evolving, the estimation of time-varying rates of natural mortality (M) remains a challenge, and the sensitivity of stock assessments and management advice to assumed M values underscores the pressing need for improved estimation methods. Using southern Grand Bank (SGB) Atlantic cod as a case study, we introduce a novel approach to estimate time-varying M. We first convert a length-based starvation M index into an age-based index, which we then include in an age-based SSAM to estimate two components of M: starvation M and a remainder component. This produces a new SGB cod SSAM with time-varying total stock M. This model produces a large decrease (68 %) in the size of the model process errors (i.e., their standard deviation) and better fit compared to a model that did not account for time-varying M, indicating that the starvation M index improves our model of stock productivity. By leveraging readily available information on fish body condition and the proportion of fish in really poor condition, the proposed methods offer a valuable solution to the challenges associated with estimating time-varying M. The proposed methods offer a tractable solution to the common struggles associated with quantifying changes in fish productivity, which is crucial for the management of dynamic systems.

LACTIC ACID BACTERIA CONTRIBUTING TO UPGRADE FODDER QUALITY

A solid nutrition stock lays the basis for contemporary animal husbandry. Application of lactic acid bacteria and their metabolites to raise the standards of feed rations as ingredients of pre- and probiotic additives, is an evolutionarily grounded basic microecological technique to uphold health status and realize genetic potential of superproductive farm animals. Throughout several decades the studies are under way at the Institute of Microbiology of the National Academy of Sciences of Belarus on isolation of lactic acid bacterial strains from various natural sources, investigation of their properties, characterization of produced bioactive agents and elaboration of the derived technologies of manufacturing diverse microbial preparations for various purposes. Specially selected lactic acid bacteria isolated from various plant sources in Belarus and adapted to local ecological environment are distinguished by intense growth, capacity to compete with other microbial species, active acidogenesis, rapid acidification of substrates down to pH 4.2 or even lower, acid resistance, a broad spectrum of fermented carbohydrates (ability to utilize hexoses, pentoses, oligo- and polysaccharides) and they served as appropriate constituents of liquid biocompositions (Lacsil, Lacsil-M), dry preparation Lacsil-MS designed to improve quality of ensiled vegetable materials. Lacsil-MS2 concentrate includes homo- and heterofermentative lactic acid bacteria consuming a wide range of carbohydrates: hexoses, pentoses, oligo- and polysaccharides, including major reserve polysaccharides of cereals and legume grasses (starch, polyfructosides). Supply of fastly growing coccoid forms of lactic acid bacteria enables to intensify the process of lactic acid fermentation at the earliest stages and swiftly reduce pH of vegetable mass. Addition of strains with elevated antagonistic activity ensures the suppression of growth of microorganisms responsible for spoilage of fodder. Upgrading consortium composition with heterofermentative lactic acid bacteria and propionic acid bacteria prevents spoilage of fodder caused by air access in the course of feeding procedure. Production by the selected microbial cultures of a set of enzymes (amylase, α-galactosidase, β-glucanase, pectinase, etc.) capable to hydrolyze hardly digestible oligosaccharides, starch-containing and non-starchy polysaccharides of plant substrates, promotes enhanced bioaccess, better assimilation, increased alimentary and energy value of feed rations. Evaluation of technology of producing feed additive based on lactic acid bacteria possessing high α-galactosidase activity acquired top relevance due to the need to eliminate deficit of fodder protein in farm rations by replenishing the share of legumes (alfalfa, lupine, soy, peas, etc.). Introduction of such feed additive incorporating lactic acid bacteria, fermenting recalcitrant oligo- and polysaccharides with α(1→6) glycoside bonds allows to raise digestibility and assimilation of proteins and carbohydrates, to increase the input ratio of legume components into composite fodder formulas, to rule out intestinal disorders (gut meteorism), contributing thereby to farm stock productivity. It was found that application of preparations comprising selected lactic acid bacteria resulted in economy of fodder expense up to 20% per each kilo of live weight increment, to augment average daily body gains by 9-12%, to increase productivity of lactating cows by 5-10%, and to diminish by 5.0% losses of digestible protein as compared with imported product analogues.

Whether ARIMA-based Portfolio Can Beat the Market Index

Portfolio optimization is a long-term topic in the financial field, which can maximize returns while minimizing risks. It is widely used in production and daily life, such as stock investment, production optimization, and engineering models. This article selects data from 10 stocks, namely KO, PG, PEP, CL, MDLZ, STZ, PM, KMB, GIS, and K, from January 24, 2024, to June 14, 2024. Firstly, this article uses the ARIMA model to learn the first 70% of the data and predict the last 30% of the data, and then uses portfolio strategy to evaluate the results. This article obtained the maximum Sharpe ratio model on the Monte Carlo effective boundary. By combining the maximum Sharpe ratio model with the SP 500 index within the same time frame, this article concludes that the market performs better. This article provides different portfolio allocation strategies for risk averse investors seeking stable positive returns in turbulent markets.

COMPARING THE WMA AND SES METHODS FOR FORECASTING STOCK PRODUCT OF MS GLOW PUTRI

Abstract: Ms Glow Putri Shop is a business that operates in the beauty sector, selling beauty products, namely skincare and bodycare, which are useful for maintaining healthy body and facial skin. However, Ms Glow Putri currently often experiences problems, namely tight competition and inventory management that is less effective in terms of sales numbers. Every month reaching ±1300 products, Ms Glow Putri also often experiences shortages and build-ups in skincare and bodycare stocks. This can reduce customer confidence so that Ms Giow Putri often experiences losses in the form of finance and other things, so this method is needed to predict some skincare and other stock supplies. bodycare provided in the following month. This method uses the Weighted Moving Average and Single Exponentiation Smoothing methods to predict supplies of skincare and bodycare stocks. The results of research on Ms GIow daughter using the Weight Moving Average Method with a weight of 5 with a MAPE of 1.08% and the SingIe Exponentiation Smooting Method with an Alpha of 0.1, namely 0.84%, then the comparison between the two methods can be stated that the SES method is the best method good, because it has the lowest error. Keywords: forecasting; ms glow putri; ses and wma Abstrak: Toko Ms Glow Putri adalah usaha yang bergerak di bidang kecantikan, menjual produk kecantikan yaitu skincare dan bodycare berguna untuk menjaga agar kesehatan kulit tubuh dan wajah tetap terjaga. Namun Ms Glow Putri saat ini sering kali mengalami permasalahan yaitu persaingan yang ketat dan manajemen persediaan yang kurang efektif dengan jumlah penjualanan. Setiap bulan mencapai ±1300 produk maka Ms Glow Putri juga sering mengalami kekurangan dan penumpukan pada stok skincare dan bodycare ini dapat mengurangi kepercayaan pelanggan sehingga Ms Glow Putri sering mengalami kerugian berupa finance dan lainnya maka perlu metode ini untuk memprediksi beberapa persediaan stok skincare dan bodycare yang disediakan pada priode di buIan berikutnya. Metode ini menggunakan metode Weighted Moving Averege dan Single Exponential Smoothing untuk memprediksi persediaan pada stok skincare maupun bodycare. HasiI penelitian pada Ms GIow Putri dengan mengggunakan Metode Weight Moving Averege dengan bobot 5 dengan MAPE 1,08% dan Metode Single Exponential Smooting dengan Alpha 0,1 yaitu 0,84% maka perbandingan antara dua metode tersebut dapat dinyatakan bahwa metode SES adaIah metode paling baik karena memiliki error terendah. Kata kunci: ms glow putri; peramalan; ses dan wma

Additive manufacturing — a new vector in the production and repair of rolling stock

The influence of the fourth industrial revolution, known as Industry 4.0, on modern industrial production and social life is analyzed. The main advantages of Industry 4.0 are presented, such as increasing productivity and occupational safety, developing new products and materials, as well as increasing the competitiveness of products. Special attention is paid to additive technologies and their role in modern engineering within the framework of the Industry 4.0 concept. The methods of additive technologies, their classification by materials and production methods, as well as their various applications in various industries are described in detail. An example of the successful use of additive technologies is presented on the example of JSC Uralvagonzavod Scientific and Production Corporation, where molds and rods for casting parts with high speed and quality are created using 3D printers. The project of introducing 3D printers into the service depots of the directorate of motor car rolling stock of JSC Russian Railways is considered, with an emphasis on the economic and temporary benefits from the use of additive technologies. The concept of introducing additive technologies in the maintenance and repair of rolling stock involves the creation of support depots on the railway network of JSC Russian Railways. In conclusion, the importance of training highly qualified specialists in the field of additive technologies and the need to develop educational programs to train future employees capable of solving complex tasks of creating and applying new industrial technologies is presented. Special attention is paid to synergetic approaches in education to combine learning with scientific activity and the creation of innovative technological solutions.

Modeling population dynamics of beluga whales in the Eastern High Arctic – Baffin Bay population

AbstractBeluga whales (Delphinapterus leucas) have a long history of subsistence harvest that has continued into the present and a history of exploitation through commercial harvest. The Eastern High Arctic – Baffin Bay (EHA) population of beluga whales has the northernmost distribution of any beluga whale population in Canada. Beluga whales from the EHA population have a single complete abundance estimate from 1996 and 3 partial abundance estimates in 1981, 2010, and 2012 from aerial surveys; reliable estimates from surveys are lacking in recent years, limiting the ability to determine population dynamics. In 2020 satellite imagery was used to estimate abundance for beluga whales in the EHA population for estuaries in the whales' summering area. We built a stochastic stock production model to estimate population dynamics from the start of reliably compiled harvest history data in 1977 to 2022, using abundance estimates from 1981, 1996, 2010, 2012, and 2020. We also extended the model 10 years into the future under 7 potential annual harvest scenarios (within the range of annual reported harvests) to calculate the probability of decline. We estimated the starting population in 1977 as 29,615 whales (95% CI = 20,765–46,251), and the estimate from 2022 was 16,495 whales (95% CI = 6,731–33,504). Landed catch of 0, 100, 200, 300, 400, 500, and 600 beluga whales annually resulted in <1%, 3%, 23%, 50%, 70%, 83%, and 90% probabilities of decline, respectively. There was a notable decrease in abundance over the time series, likely caused by harvest pressure. Harvest in recent years has ranged from 155–553 catches per year, and our results suggest that 108 landed catches per year equates to a 5% risk of decline, the low risk goal for precautionary fisheries management, which aligns with population conservation goals. Our model is a first step in understanding the EHA beluga whale population dynamics using what data are available and suggests that current harvests in some years may result in a population decline and should be monitored.

Influence of water evaporation on elastohydrodynamic lubrication with water-containing polyalkylene glycols

The reduction of frictional power losses in power transmitting gears takes a crucial role in the design of energy- and resource-efficient drivetrains. Water-containing lubricants like glycerol and polyalkylene glycols have shown great potential in achieving friction within the superlubricity regime with coefficients of friction lower than 0.01 under elastohydrodynamic lubrication. Additionally, a bio-based production of the base stocks can lead to the development of green lubricants. However, one challenge associated with the application of water-containing lubricants to gearboxes is the evaporation of water and its impact on the lubricant properties. In this study, the influence of water evaporation on elastohydrodynamic friction and film thickness was investigated for three water-containing polyalkylene glycols. Two nominal water contents of 20 wt% and 40 wt% and two viscosities were considered. The results show that the friction increases continuously with higher evaporated water content, while the overall friction level remains low in nearly water-free states. A similar trend is observed for film thickness, where the strong increase in viscosity results in a notable increase in film thickness. Nevertheless, the sensitivity of friction and film thickness to water evaporation is low for small amounts of evaporated water. This allows generous thresholds for permissible variations in water content.

Improving the galvanized roll stock production technology by using machine learning methods: a case study of the novolipetsk steel (NLMK) continuous hot-dip galvanizing unit (CHGU-1)

Improving the galvanized roll stock production technology by using machine learning methods: a case study of the novolipetsk steel (NLMK) continuous hot-dip galvanizing unit (CHGU-1)

Open-source cold and hot scientific sheet press for investigating polymer-based material properties

To produce samples for both material testing and molded sheets/parts, this article details an open-source scientific cold and hot press design. It consists of two independent and modular upper and lower plate (929 cm2) assemblies each containing four 125 W insulated steel strip heaters. The steel housing for these heaters is entirely modular and designed for ease of manufacture, assembly, and customization. This system allows a researcher with access to a hydraulic press to repurpose existing equipment into a multipurpose hot and cold press, or if an independent machine is warranted, an additional welded support frame and commercially available bottle jack offer standalone operation. By utilizing this small-scale hot press either in conjunction with a hydraulic press or on its own, samples can be produced to determine the critical material properties of any polymer, composite, or polymer blend. A series of modular molds allow for the rapid production of flat sheet stock and solid testing samples adhering to the ASTM D695 standard for rigid plastics tested in compression and ASTM D638 standard for testing plastics in tension. The sheet mold offers the user the ability to produce stock sheets that can be cut and assembled into 2.5-D applications with post processing.

Production of Bio-Diesel from Dairy Waste Scum

Abstract-Dairy factory waste scums are increasingly being considered a valuable resource. However, these wastes may also contain contaminants, natural or artificial, that may adversely affect the land or water to which they are discharged. The study investigates the potential of using dairy waste scum as a feed stock for bio-diesel production. Present study optimized the parameters involved in the alkali catalysed Trans esterification process of dairy waste scum oil. The effects of methanol to oil ratio, temperature and amount of KOH were investigated. A study was conducted to evaluate the capability of production of biodiesel from consortium of native microalgae culture in dairy farm treated waste water. Native algal strains were isolated from dairy farm waste waters collection tank (untreated wastewater) as well as from holding tank (treated wastewater). The consortium members were selected on the basis of fluorescence response after treating with Nile red reagent. Preliminary studies of two commercial and consortium often native strains of algae showed good growth in waste waters. A consortium of native strains was found capable to remove more than 98% nutrients from treated waste water. The biomass production and lipid content of consortium cultivated in treated waste water were 153.54t ha-1 year-1 and 16.89%, respectively. 72.70% of algal lipid obtained from consortium could be converted into biodiesel. The present study found that bio- diesel from dairy waste scum is quite suitable as an alternative to petroleum diesel with recommended fuel properties as per ASTM standards. By using dairy waste scum as a feed stock for bio diesel and the environmental impact related to the disposal of dairy scum Keywords: Environment,Bio-Diesel,Dairy Waste Scum, Extraction of Lipids

Transfer and bioaccumulation of chemical and biological contaminants in the marine polychaete Hediste diversicolor (OF müller 1776) when reared on salmon aquaculture sludge

Side streams from aquaculture production such as fish sludge poses ample opportunities for biological upcycling, as the sludge contains high amounts of nutrients, energy and valuable biochemicals, making it an ideal food for extractive species. Sludge has been proposed as a feed stock for polychaete production, which in turn can be utilized live in shrimp aquaculture or as an aquafeed ingredient. However, the biosafety of such value chains has not yet been addressed. We conducted an experiment exposing the polychaete Hediste diversicolor to aquaculture sludge spiked with four different fish pathogens (Mycobacterium salmoniphilum, Yersinia ruckeri, Infectious Pancreatic Necrosis (IPN) and Infectious Salmon Anaemia (ISA)) known to cause diseases in Atlantic salmon (Salmo salar L.). Moreover, we assessed whether heavy metals and other potentially hazardous elements present in fish sludge bioaccumulates in the polychaetes. Neither of the bacteria nor viruses could be detected in the polychaetes after 14 days of continuous exposure. Seven of the 15 elements we analysed showed bioaccumulation factors significantly below one, meaning biodilution, while the other eight did not differ from one, meaning no bioaccumulation. None of the elements showed a significant bioaccumulation. Further on, none of the heavy metals found in the polychaetes at the end of our experiment exceeded the EU regulatory maximum levels for fish feed ingredients. The current results suggest that a H. diversicolor can reared on aquaculture sludge, and aquaculture sludge may serve as feed stock for polychaete production without the product exceeding EU regulations for contaminants in animal feed.

Growth, poverty trap and escape

The well-known Solow growth model is the workhorse model of the theory of economic growth, which studies capital accumulation in a model economy as a function of time with capital stock, labour and technology-based production as the basic ingredients. The capital is assumed to be in the form of manufacturing equipment and materials. Two important parameters of the model are: the saving fraction s of the output of a production function and the technology efficiency parameter A , appearing in the production function. The saved fraction of the output is fully invested in the generation of new capital and the rest is consumed. The capital stock also depreciates as a function of time due to the wearing out of old capital and the increase in the size of the labour population. We propose a stochastic Solow growth model assuming the saving fraction to be a sigmoidal function of the per capita capital kp . We derive analytically the steady state probability distribution P(kp) and demonstrate the existence of a poverty trap, of central concern in development economics. In a parameter regime, P(kp) is bimodal with the twin peaks corresponding to states of poverty and well-being, respectively. The associated potential landscape has two valleys with fluctuation-driven transitions between them. The mean exit times from the valleys are computed and one finds that the escape from a poverty trap is more favourable at higher values of A. We identify a critical value of Ac below (above) which the state of poverty (well-being) dominates and propose two early signatures of the regime shift occurring at Ac . The economic model, with conceptual foundations in nonlinear dynamics and statistical mechanics, shares universal features with dynamical models from diverse disciplines like ecology and cell biology.

Stock exchange operations as a tool for increase in the level of economic security of the enterprise

The problem of increasing the level of economic security of the enterprise is relevant for enterprises in market conditions of business, which are characterized by a high level of instability. However, in today's conditions of increased instability and increased threats, it is necessary to further deepen the study of the problem in order to find new effective tools for increasing the level of economic security of the enterprise. Exchange transactions are among such instruments. The main components of economic security, which can be positively affected by stock exchange operations, are financial, marketing and production. Prospects for the use of stock exchange operations to increase the level of financial security of the enterprise: operations on the commodity exchange, the purpose of which may be the purchase of production stocks and the sale of products of own production, will allow forecasting the level of expenses and the level of income both by cost and by the time of formation, which has a positive effect on the effectiveness of cash flow management, accordingly, has a positive effect on the level of solvency of the enterprise; operations on the stock market allow you to effectively attract financial resources to ensure the operation of the enterprise, and can also be used for the placement of equity securities of the enterprise and the effective search for co-owners; operations with futures and option contracts with a sufficient level of professional knowledge of the company's specialists will allow to provide the company with production resources and sell the company's products on the most favorable terms. The impact of stock exchange operations on marketing security: the stock market is an effective source of sales of products, within which it is possible to enter into contracts for future supply with a clearly established price level and terms of performance; due to the concentration of potential counterparties, it is possible to increase the volume of sales of the company's products; thanks to the desire to reach the level of the exchange standard, the tendency to increase the quality of products and their competitiveness is ensured; from the point of view of brand development, exchange transactions can have a negative impact, because during exchange trading, depersonalization of products and counterparties and maximum standardization are characteristic. The impact of stock exchange operations on production safety: an increase in the level of product quality to the level of the stock exchange standard, uninterrupted provision of the production process with raw materials and materials, thanks to which downtime can be reduced, the rhythm of production increased and the level of utilization of the production capacity of the enterprise. Therefore, the positive impact of stock exchange operations on the vast majority of functional components of the enterprise's economic security allows to increase its level and achieve the fulfillment of tasks related to increasing the level of competitiveness of the enterprise and ensuring the stability of business conditions.

Stock exchange operations in an anti-crisis management system of the enterprise

Today, in the process of building an effective system of anti-crisis management of the enterprise, more attention should be paid to such less common, but highly effective tools as stock transactions. Anti-crisis management is a certain set of strategic measures and tactical actions aimed at identifying, preventing and overcoming crisis phenomena in the company's activities, as well as impulses that potentially threaten the development of crisis phenomena in the future. The main directions of action are the following: development of the general anti-crisis strategy of the enterprise, ensuring the financial stability of the enterprise, implementation of the risk management system, restructuring of the enterprise and its business processes, personnel and communications management, increasing the efficiency of the marketing system, etc. Speaking about the place of stock exchange operations in the system of anti-crisis management of the enterprise, it should be noted that they can be considered as a tool in the middle of some of the above measures, namely optimization of business processes, improvement of the level of communications and activation of marketing. In all these aspects, the use of exchange operations can be effective. In our opinion, transactions with goods and derivative financial instruments require the main attention. Speaking about the optimization of business processes, the following advantages of cooperation with stock exchange institutions can be distinguished: guaranteed replenishment of production stocks with raw materials and materials of the required quality and quantity due to the conclusion of term exchange agreements for their supply, the forecast level of prices for raw materials and materials, which is fixed during the conclusion of exchange agreements , clearly defined conditions of supply. Access to the stock market also has a positive effect on the level of business communications, because it is the stock exchange that maximally concentrates all interested parties regarding specific types of goods, which contributes to the intensification of business activity. Exchange operations can also be considered as a highly effective tool for activating the marketing activities of the enterprise. In addition to the purchase of raw materials on the stock exchange for your activity, you can use the stock market for the sale of goods manufactured by the enterprise. In this way, the company can guarantee itself future sales in a certain forecasted price range, and accordingly, reasonable planning of the company's performance indicators, cash flows is possible, therefore, it becomes possible to manage insolvency, which is the main crisis impulse for the company.