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In this paper, we review observational and modelling results on the upwelling in the inner tropical Atlantic. We focus on the physical processes that drive the seasonal variability of surface cooling and upward nutrient flux required to explain the seasonality of primary productivity. We separately consider the equatorial upwelling system, the northern coastal upwelling system of the Gulf of Guinea and the tropical Angolan upwelling system. For the equatorial regime, we discuss the forcing of upwelling velocity and turbulent mixing as well as the underlying dynamics responsible for thermocline movements and current structure. The coastal upwelling system in the Gulf of Guinea is concentrated along northern boundary and is driven by both, local and remote forcing. The particular role of the Guinea Current, nonlinearity and the shape of the coastline are emphasized. For the tropical Angolan upwelling, we show that this system is not wind-driven, but instead results from the combined effect of coastally trapped waves, surface heat and freshwater fluxes, and turbulent mixing. Finally, we review recent changes in the upwelling systems associated with climate variability and global warming and address possible responses of upwelling systems in future scenarios. [ABSTRACT FROM AUTHOR]

Many SSA countries are low-Income countries with inadequate access to basic infrastructure including energy. According to IEA 2018, SSA has the least energy access rates globally. Thirteen countries in SSA, do not have up to 25% access, unlike developing Asia where there is only one country (World Bank, 2018). To this end, this empirical investigation focuses on the nexus between energy consumption and export performance of Sub-Sahara African countries. Generally, the study examines the contribution of energy consumption to real export of goods and services and specifically to the export of manufactured goods. This is very crucial as many countries in Sub-Saharan Africa heavily rely on the export of primary products. They trade on a small range of agricultural products and a small number of markets for their exports. To achieve this, Dumitrescu and Hurlin (2012) Granger causality procedure and Pooled Mean Group (PMG) were employed to determine the direction of causality and estimate the effect of energy consumption (renewable and non-renewable) on export performance. This estimation approach constrains the long run coefficients to be identical, but allows the short run coefficients and error variances to differ across groups. The estimated model in this study is constructed within the framework of multivariate panel analysis. Specifically, two models are specified with real export of goods and services and export of manufacturing goods as dependents variables. The study established that real export granger causes renewable energy, renewable energy, granger causes manufacturing export and manufacturing export granger causes non-renewable energy. More importantly, the study established the relative importance of renewable energy to export performance in SSA. The study, therefore, recommends that as sub-region is aspiring to move away from resource-based exports to manufacturing exports, it is critical that the countries in the region scale up access to energy and look more in the direction of renewable energy to bring this aspiration to reality. [ABSTRACT FROM AUTHOR]

Recent observations suggest that substantial phytoplankton blooms occur under sea ice on Arctic continental shelves during June and July. This is opposed to the traditional view that no significant biomass is produced in sea‐ice covered waters. However, no observational estimates are available on the Arctic‐wide primary production beneath sea ice. Here, using a fully coupled Arctic system model, we estimate that 63%/41% of the total primary production in the central Arctic occurs in waters covered by sea ice that is ≥50%/≥85% concentration. The total primary production there is increasing at a rate of 5.2% per decade during 1980–2018. Increased light transmission, due to the removal of sea ice, more extensive melt ponds, and thinner sea ice, is implicated as the main cause of increasing trends in primary production. Plain Language Summary: At present, there are no Arctic‐wide observations and estimates of primary production beneath Arctic sea ice because it cannot be measured by satellite and is difficult to access via ship. Utilizing our state‐of‐the‐art Arctic system model, we have quantified the primary production beneath Arctic sea ice and our findings show that the majority of production occurs in waters covered by at least 50% ice. This analysis represents a major revision to the traditional view that no significant biomass is produced in sea‐ice covered waters. Our results are consistent with recent and very limited (in space and time) observational studies; however, we provide information for the entire Arctic Ocean, including increasing trends in production over the time period of 1980–2018. Key Points: The majority of modeled primary production in the central Arctic is found beneath sea iceThe annual cycle of primary production in the central Arctic peaks in June due to the under‐ice fraction of productionPrimary production and photosynthetically active radiation are increasing in the central Arctic over the period 1980–2018 [ABSTRACT FROM AUTHOR]

Diatoms are an ecologically fundamental and highly diverse group of algae, dominating marine primary production in both open-water and coastal communities. The diatoms include both centric species, which may have radial or polar symmetry, and the pennates, which include raphid and araphid species and arose within the centric lineage. Here, we use combined microscopic and molecular information to reclassify a diatom strain CCMP470, previously annotated as a radial centric species related to Leptocylindrus danicus, as an araphid pennate species in the staurosiroid lineage, within the genus Plagiostriata. CCMP470 shares key ultrastructural features with Plagiostriata taxa, such as the presence of a sternum with parallel striae, and the presence of a highly reduced labiate process on its valve; and this evolutionary position is robustly supported by multigene phylogenetic analysis. We additionally present a draft genome of CCMP470, which is the first genome available for a staurosiroid lineage. 270 Pfams (19%) found in the CCMP470 genome are not known in other diatom genomes, which otherwise does not hold big novelties compared to genomes of non-staurosiroid diatoms. Notably, our DNA library contains the genome of a bacterium within the Rhodobacterales, an alpha-proteobacterial lineage known frequently to associate with algae. We demonstrate the presence of commensal alpha-proteobacterial sequences in other published algal genome and transcriptome datasets, which may indicate widespread and persistent co-occurrence. [ABSTRACT FROM AUTHOR]

Submerged aquatic vegetation (SAV) provides primary products for the food web, as well as shelter and nursery for many juvenile species. SAV can also attenuate waves, stabilize the seabed, and improve water quality. These environmental services are influenced by the dynamic motion of SAV. In this paper, a consistent‐mass cable model was developed to investigate flow interaction with a flexible vegetation blade. Compared with previous vegetation models, the cable model showed improvements in simulating blade motions in waves with and without currents, especially for "second‐normal‐mode‐like" blade motion. Wave asymmetry would cause blade motion to be asymmetric. However, asymmetric blade motion may also occur in symmetric waves. Results indicate that the asymmetric blade motion in symmetric waves is induced by two major mechanisms: (i) the spatial asymmetry of the encountered wave orbital velocities (wave motion relative to blade) due to blade displacements and (ii) the asymmetric action on the blade by vertical wave orbital velocities. Consequently, the blade motion is asymmetric even underneath symmetric waves unless (i) blade length (l) is much smaller than the wavelength (l/L≪1), (ii) blade length is much smaller than the water depth (l/h≪1) in finite water depth waves, or (iii) water depth is much smaller than the wavelength (h/L≪1). Peak asymmetric blade motion occurs as l/L increases to a critical value. The peak asymmetry increases with wave height and blade length but decreases with increasing blade flexural rigidity. Blade motion characteristics play an important role in wave‐vegetation interaction, wave‐driven currents, wave‐attenuation capacity, breakage of vegetation and ecosystem services. Plain Language Summary: Submerged aquatic vegetation (SAV) can reduce wave energy, stabilize the seabed, and improve water quality. These environmental services are influenced by SAV motion. In this paper, a numerical model was developed to study flow interaction with a flexible blade. Compared with previous vegetation models, the cable model showed improvements in simulating blade motions in waves with and without currents. Wave asymmetry would cause blade motion to be asymmetric. However, asymmetric blade motion may also occur in symmetric waves. Results indicate that the asymmetric motion in symmetric waves is induced by two major factors: (i) the spatial asymmetry of the encountered wave velocities (wave motion relative to blade) due to blade displacements and (ii) the asymmetric action on the blade by vertical wave velocities. Consequently, the blade motion is asymmetric unless (i) blade length is much smaller than the wavelength, (ii) blade length is much smaller than the water depth in non‐deep‐water waves, or (iii) water depth is much smaller than the wavelength. Peak asymmetric blade motion increases with wave height and blade length but decreases with increasing blade flexural rigidity. Blade motion characteristics play an important role in wave‐vegetation interaction, wave‐driven currents, wave‐attenuation capacity, breakage of vegetation and ecosystem services. Key Points: Simulations for the motion of flexible blades in waves with and without currents are improved by using a consistent‐mass cable modelBlade motion is asymmetric due to blade deflection and vertical wave velocity but symmetric if blade length is far less than the wavelengthPeak asymmetry of vegetation blade motion increases with wave height and blade length but decreases with increasing blade flexural rigidity [ABSTRACT FROM AUTHOR]

This paper determines an optimum production schedule and raw material ordering policy for a family of products that share a common piece of production facility, and the inventory operates under a shelf life constraint. The problem of manufacturing a family of products under shelf life is addressed here mainly under three major issues: adjusted production rate, adjusted cycle time, and simultaneous adjustment of production rate and cycle time. This research addressed the issues in two major parts: the first part comprises planning an optimum production schedule and material ordering policy for a family of products with a constant production cost for operating the machines. The second part of the research considers a generalized production cost of operation where the cost of operation may increase or decrease depending on the production system. Results are demonstrated to show the computational mechanics and incremental advantages over the other models. A sensitivity analysis is performed to study the effect of variability of some parameters that play important roles in the models. An empirical test has also been conducted to show the relative performance of the models. [ABSTRACT FROM AUTHOR]

This paper studies short-term sensitivity between exchange market pressure and various domestic and external factors in primary commodity-exporting emerging markets. The paper focuses on the top country-commodity groups in sugar, cereal, fuels, ores and coffee during the pre-peak and post-peak commodity price periods across floating and pegged exchange rate regimes, using the price of crude oil as a general benchmark. Employing a panel model and panel VAR analysis, the paper finds the heterogeneity of response patterns unique to country-commodity groups and exchange rate regimes. According to the results, in flexible regimes, volatility occurs via the foreign exchange market, interest rates, and domestic credit cycles, feeding into the social costs for structurally weaker economies. Hard exchange-rate pegs often result in a drain on international reserves as the terms of trade deteriorate following post-price peaks, leading to unpopular depreciation. These results accentuate concerns over uneven international trade patterns, an open economy's short-term foreign exchange policy, and speculative capital flows. Such sensitivity has broad implications for macroeconomic balance and the sustainability of implied exchange rate targets in the presence of a foreign exchange constraint across emerging markets. [ABSTRACT FROM AUTHOR]

Abstract Sustainable growth of the lithium-ion battery (LIB) industry requires a safe supply of raw materials and proper end-of-life management for products. The lack of research on domestic critical raw materials and on management systems has limited the formulation of relevant policies for LIB-related industries. Here, a critical raw material (CRM) evaluation model was developed to identify the criticality associated with the supply risk (SR) and economic importance (EI) of different materials for the Chinese LIB industry. Dynamic materials flow analyses of the relevant critical materials were carried out by integrating a trade-linked model. Criticality analysis identifies the importance of different materials and optimizes the subsequent materials flow analysis. The results showed that the in-use stocks share large portions of material flow for Li, Ni, Co and graphite and further suggests that the market will not be saturated before 2025. For the end-of-life stage, less than 40 wt% of the materials in LIBs can be recycled under the current scheme of materials flow in China; this finding puts significant pressure on proper waste management. Consequently, it is very important to identify effective methods for utilizing the growing amount of waste materials and to provide a resource supplement for the Chinese LIB industry. This research provides guidelines for improving management strategies relevant to the critical materials in the LIB industry, for increasing resource efficiency, and for managing critical resources. Graphical abstract Image 1 Highlights • MFA for multiple elements in LIB industry is still scattered. • A CRMs evaluation system was proposed to optimize the further MFA. • Sankey diagrams of Li, Co, Ni and C reveal their status in Chinese LIB industry. • The stock and obsolete amount from 2012 to 2025 were estimated and forecasted. [ABSTRACT FROM AUTHOR]

Process planning is the task of generating a plan for transforming raw material to its finished form according to design specifications. The existence of alternative feasible process plans for a part and the manufacture of several parts in a single facility sharing constrained resources, makes careful selection of process plans essential. This paper formalizes the selection of process plans with the objective of minimizing the total processing time and the total number of processing steps. The set of plans are then consolidated to minimize the resources used. This is accompanied by intangible benefits such as simplified planning and scheduling, fewer constraints on designing the layout, and an overall reduction in the manufacturing cost. As a word of caution, it may be added that process plans have wide ranging impact on factory operations and it is unrealistic to expect a single model to be comprehensive in addressing the problem. The model outlined in the paper highlights the key issues and provides an analytical basis for selecting process plans. [ABSTRACT FROM AUTHOR]

The coordination of production and inventory decisions for raw materials, intermediate products and finished goods is important. We compare some decision rules for a firm that uses a single raw material to manufacture n different parts which are then assembled into the final product. Demand for the final product is probabilistic and there are costs of holding inventory and of ordering, manufacture and assembly. These characteristics are an idealization of the problem faced by a manufacturer of scaffolds in which the major processes are the manufacture of different sheet metal parts and their assembly. We develop production rules that use system-wide information. We use simulation to evaluated the performance of these rules and compare system behaviour to that under production rules that are derived separately for each item and use only local information about that item's status. [ABSTRACT FROM AUTHOR]

This paper presents three approaches to minimize and eliminate scrap from stamping a single shape arranged in a single row or double rows on strip raw materials. In the first approach, interlocking shapes are generated. Although such shapes are scrap-free, they require congruent lines in the design. At the early stages of the design process, a skilful designer can compromise between functional features and symmetric features to improve nesting. The second approach is to characterize a shape by parallel lines bounding it. Specifically, the method to find a minimum area parallelogram that encloses a given convex shape is discussed. The result, gives the optimum arrangement of a convex shape in single row. The third approach involves the nesting of a given shape in a specified pattern. Three computational algorithms for the single and double row arrangements are given. The double row arrangement includes a half-turn or a mirror reflection. The three approaches are all based on the concept of interlocking shapes and they can readily be implemented on a small computer. Depending on the design environment and the piece shape, one of the approaches can be used. [ABSTRACT FROM AUTHOR]

The article presents an analysis of Standard Oil Company's vertical integration strategies from the period of 1911 until 1963. The author feels that vertical integration is best suited to industries which deal with raw materials such as frozen food processors and forest product companies. Generally, conglomerate companies that use vertical integration as part of their business plan have a minimum of two companies that deal with supplying materials, distributing the materials to manufacturing plants, manufacturing goods, distributing finished products, or retailing their processed goods.

The article discusses different aspects of the price control system implemented in Canada on October 18, 1941. The system places a maximum selling price for all commodities (unless specifically exempted), twelve essential service areas, and the rental of all real property. The author describes how the federal government accounted for the falling profit margins of retailers and wholesalers as the price regulation went into transition. Furthermore, he points out that the price cap is individual to the type of retail outlet, and that seasonal and new merchandise is taken into special consideration. The enforcement of the pricing system is discussed along with the effects of its use.

The article examines the sufficiency of world resources for the provision of adequate living standards. Use of large quantities of metals results to decreased grades of raw materials in many areas of industrial activity. With the increasing population, it is expected that there will be a rise in the consumption of energy and other raw materials. Regarding food supply, a major increase will require the application of enormous amounts of technology, a great deal of capital investment and dissemination of modern agricultural knowledge throughout the world. The depletion of resources will make it more difficult for less developed areas of the world to obtain significant materials.

This paper documents the global crude oil market as a key driver of international migration and remittances. Structural estimation documents that crude oil supply and demand shocks induce sizeable remittances flows. The sign and magnitude of remitter outflows differ across countries and structural shocks. A multilateral global general equilibrium model is used to show how oil‐exporting remitters generate international remittance and migration spillovers from crude oil price movements. Remittees' economic outcomes from remittances and migration channels are found to be dominated by terms of trade channels for shocks to the global market for crude oil. Due to this, studies of remittance flows need to account for the source of the commodity price movement if using the correlation between remittee real GDP and remittance inflows. [ABSTRACT FROM AUTHOR]

We construct a model of the consequences of terrorism on trade, where firms in trading nations face different costs arising from domestic and transnational terrorism. Using a dyadic dataset in a gravity model, we test terrorism’s effects on overall trade, exports, and imports, while allowing for disaggregation by primary commodities and manufactured goods. While domestic and transnational terrorism have marginal or no significant influence on the overall trade of primary products, both types of terrorism significantly reduce the overall trade of manufactured goods. This novel finding for a global sample indicates the avenue by which terrorism reduces trade and suggests why previous global studies that looked at all trade generally found modest impacts. Moreover, both domestic and transnational terrorism have a detrimental effect on manufactured imports. The larger apparent reduction for transnational terrorism is not statistically different from that of domestic terrorism. A more mixed picture characterizes the effect of terrorism on exports. Domestic terrorism reduces manufactured exports and increases primary exports, while transnational terrorism reduces primary exports. Placebo tests support our hypothesized causality. [ABSTRACT FROM AUTHOR]