Significant Drop In Productivity Research Articles

Characterization of macadamia ringspot-associated virus, a novel Orthotospovirus associated with Macadamia integrifolia in South Africa

South Africa is the largest producer of macadamias in the world, producing an estimated 61,288 tons nut-in-shell in 2022. In order to ensure the sustainability of the industry, it is important that research focuses on the control and eradication of economically important pests and diseases. Macadamia trees in the Mpumalanga Lowveld of South Africa have for some time shown severe chlorosis, which coincides with a significant drop in production, with losses of up to 60% being recorded. The disease has since been coined Macadamia Chlorosis Disease (MCD). In an attempt to determine whether MCD may be associated with a virus, high-throughput Illumina sequencing was performed on RNA extracted from both diseased and healthy trees collected from farms in Mpumalanga. Subsequent data analyses could not link a specific virus to MCD, however, reads spanning the full genome of a novel virus belonging to the Orthotospovirus genus were obtained. An RT-PCR assay was optimized for the detection of this virus and subsequent surveys linked the virus to ringspot symptoms which are commonly observed on different macadamia cultivars. The virus has to date been identified from orchards in Mpumalanga, Limpopo and KwaZulu-Natal. Other viruses described in the genus are known to cause severe crop losses and it is therefore important that the virus, provisionally named macadamia ringspot-associated virus (MRSV), be further studied to determine whether association with this virus can lead to yield losses, and whether appropriate control strategies must be implemented to prevent the spread of MRSV.

Firm productivity in the Energy-electricity sector over the last two decades with crisis: The role of cross-listing

Novel to the literature, this study examines how cross-listing impacts firms’ productivity in Energy sector. Annual data of firm cross-listing over the last two decades with crisis (2002-2022) is employed for our analyses. We find evidence of significant drop in productivity after Energy firms (including electricity firms) cross-list in the US market. Meanwhile, we do not find strong evidence of significant decreases in firm productivity from other sectors in our sample. We note one possible explanation for this finding is that after cross-listing, Energy firms appear to utilize their increased capital to heavily invest in infrastructure, equipment, and plants for expansion, which might eventually damage their productivity. To seek for more thorough explanations for such decreases in Energy firms' productivity after cross-listing, we identify the determinants of firm productivity in Energy sector. Our results provide strong evidence that the increases in capital expenditures after Energy firms cross-list appear to be associated with the decreases in firm productivity. Notably, we note that negative impacts of capital expenditures (after cross-listing) and state ownership on firm productivity become much stronger and more statistically significant in developed countries than in emerging countries. Last, corporate governance and firm liquidity are found to be two determinants that help improve firm productivity in both electricity firms and other energy firms.

Influence of targeted selective anthelmintic treatment on the productive performance of wool and hair lambs naturally infected with gastrointestinal nematodes in Brazil.

Targeted selective treatment (TST) is an alternative method to reduce the use of anthelmintics and delay the development of resistant nematode populations. However, there is limited information on the actual effects of this type of treatment on livestock productivity. The objective of this study was to evaluate the production performance of Santa Ines (hair) and Ile de France (wool) lambs naturally infected with gastrointestinal nematodes (GIN) under TST based on packed cell volume (PCV) versus suppressive anthelmintic treatments. Thirty-eight lambs were divided into two treatment groups: Suppressive treatment, animals were drenched with monepantel every two weeks and TST, animals were treated with the same anthelmintic when they presented PCV ≤ 20%. Feces, blood, and weight were measured weekly to determine eggs per gram of feces, PCV, total plasma protein, and weight gain. After animals were slaughtered, carcasses were weighed to determine carcass yield. In the TST group, substantial productive losses of approximately 21.3% in the wool and 25.9% in the hair lambs were observed in body weight compared to their counterparts. Significant differences in hematological variables occurred over the experimental period, especially in the wool lambs under TST. Favorable environmental conditions enabled infective larvae to survive and thrive on pasture. Haemonchus contortus and intestinal nematodes were the most common parasites found in the Ile de France lambs and the Santa Ines lambs, respectively. Although TST prevented mortality, it did not prevent production losses. Both breeds showed a significant drop in production due to GIN parasitism.

CFD Modeling and Analysis of Particle Size Reduction and Its Effect on Blast Furnace Ironmaking

Particle size reduction inevitably occurs inside ironmaking blast furnaces (BFs) but is not studied under BF conditions due to the lack of an effective tool. This paper simulates this phenomenon inside a 5000-m3 commercial BF using a recently developed three-dimensional computational fluid dynamics (CFD) process model. In particular, the sinter reduction degradation and coke gasification are modeled for considering the size reduction. By incorporating this information in the BF model, the in-furnace states and global performance are evaluated with respect to sinter reduction degradation index (RDI) under different conditions, e.g., keeping a constant blast rate or gas pressure drop. The results show that with increasing RDI, the bed permeability deteriorates, and there exists a critical value of RDI beyond which the decreased bed permeability leads to a significant drop in productivity for a given gas pressure drop. However, this problem can be mitigated substantially by charging more coke particles at the furnace periphery under the conditions considered. The proposed approach offers an extended capability to model and control BF operations.

Specialization and competitiveness: analysis of Brazilian exports of cocoa beans and products

Cocoa farming was and still is an economic activity of great importance for the economy of Brazil and the rest of the world. During the last few decades, African and Asian countries have increased their presence as producers, increasing global competition and leading to changes in Brazil’s participation in foreign markets. In this context, this study analyzes the competitiveness of Brazilian cocoa farming based on exports of cocoa beans and products (powder and press cake, cocoa butter and cocoa liquor).To do so, foreign trade indicators were calculated for the period from 1996 to 2016, in the form of: revealed comparative advantage (RCA); coverage ratio (CR); and trade balance contribution index (TBCI). The data showed that, from 1997, Brazil has moved from being an exporter to import cocoa beans, as a result of the significant drop in production and productivity of the agriculture of the state of Bahia, the largest exporter and importer of cocoa beans in Brazil. In several years, exports of cocoa butter accounted for the greatest contribution to foreign trade. In general, the indicators showed the poor competitive performance of Brazil in the international market of cocoa beans and products.The country lost market share and suffered the greatest loss of competitiveness in the export of such commodities. There is a need to formulate competitive strategies to support the cocoa industry in order to increase its global market share. This could involve conquering more dynamic or little-exploited markets, mainly for cocoa products which offer higher added value.

북한의 자본스톡 추정 및 시사점 (Estimating Capital Stock in North Korea and Its Implications)

Korean Abstract: 본고는 1955~2018년중 북한의 투자시계열을 구축하고 영구재고법으로 자본스톡을 추계한 후 이를 통해 북한의 경제성장 요인을 살펴본 것이다. 자본스톡은 건설자산과 설비자산을 구분하여 추정하였다. 추정 결과 북한의 자본스톡은 1955년 이후 1989년까지 빠르게 증가하다 1990년대에 크게 감소하였으며 2000년대 이후 다시 회복되었다. 북한의 자본스톡은 2018년 현재 1989년보다 24% 높은 수준이고, GDP의 3.9배로 선진국에서 일반적으로 관측되는 3배 수준보다 많은 것으로 추정되었다. 2018년 현재 전체 자본스톡 가운데 설비자산이 8%에 불과하였는데 이는 남한의 1970~90년 평균 수준인 32%와 대비되는 모습이다. 성장회계 분석 결과 북한은 경제성장 초기에 외연적 성장을 달성하기도 하였으나 이후 총요소생산성 감소에 주로 기인하여 성장이 정체되거나 부진한 회복세를 보인 것으로 나타났다. 1990년대 경제위기를 겪었으며 2000년 이후에는 투입 증가율이 낮아진 가운데 생산성 부진이 지속되면서 저성장 기조가 유지되었다. 2017년 이후에는 제재 여파로 투입증가율이 더욱 낮아지고 생산성이 크게 감소하여 경제성장률이 급락하였다. 한편 빈곤의 덫과 유휴자본의 특징을 보인 북한의 1990년대 경제위기 이후는 레온티에프 생산함수에 기반한 해로드-도마 성장모형으로 해석해 볼 수 있다. 북한은 현재 자본재 금수조치로 성장여건이 크게 악화된 상황인 만큼 기업소와 농장의 소유구조 및 운영방식의 혁신을 통해 생산성과 효율성, 창의성을 증진하는 제도개선이 요구되고 있다. 또한 북한이 경제침체로부터 벗어나려면 인적 물적 자본 축적이 필수적인 만큼 선진국의 자본과 기술 도입을 위해 대외관계 개선 및 적극적 개방정책이 시급해 보인다. 본고의 추정에도 불구하고 개별자산의 역사적 축적과정과의 비교, 디플레이터 산출, 성장 추정에 사용되는 물량자료의 정확성 제고 등을 위한 노력이 계속되어야 한다. 특히 본고의 자본스톡 추정은 북한의 여타 거시통계의 추정 개선 작업과 연계된 만큼 아직 미완성의 잠정치로 이해되어야 한다. English Abstract: This study aims to estimate the capital stock in North Korea from 1955 to 2018, based on the perpetual inventory method, and then to explain its economic growth. The capital stock is estimated by decomposing it into construction assets and equipment assets. Estimates show that North Korea's capital stock increased rapidly from 1955 to 1989, then decreased significantly in the 1990s, and recovered since the 2000s. The capital stock estimate as of 2018 stands at 24% higher than that in 1989. The capital stock/GDP ratio as of 2018 is around 3.9 times, which is higher than 3.0, the ratio commonly observed in many advanced economies. The estimated share of equipment capital within total capital is only 8% as of 2018, which compares with the corresponding rate (32%) during the 1970-1990 period in South Korea. Growth accounting analysis shows that North Korea achieved a rapid input-led growth in the early stages of economic growth, but has since shown stagnant or sluggish growth, due mainly to a drop in total factor productivity. It suffered from the economic crisis in the 1990s, and after 2000 the low growth pattern was maintained as productivity continued to remain sluggish amid a lower input growth rate. Since 2017, the economic growth rate has plummeted due to a further drop in the input growth rate and a significant drop in productivity in the wake of sanctions. We believe that the negative GDP growth rate during the so-called “Arduous March Period,” and the low growth seen in succeeding periods that has been characterized by idle capacity with a poverty trap, can be explained by a Harrod (1939)-Domar (1946) model based on the Leontief production function as outlined in Barro and Sala-i-Martin (1995). As North Korea's growth conditions have deteriorated significantly due to the embargo on capital goods, it is required to improve its system that promotes productivity, efficiency and creativity through innovation in the ownership structure and management of farms and enterprises. More favorable foreign relations and an active opening policy are also necessary to attract foreign investment and technology, which is essential for human and physical capital accumulation and the resulting economic growth. Despite the estimates of this study, efforts should continue to be made to compare the historical accumulation process of individual assets, to calculate deflators, and to enhance the accuracy of production data used in estimating economic growth. In particular, the capital stock estimates in this paper should be understood as preliminary figures, as it is linked to work to improve the estimation of North Korea's other macro statistics.

Análisis de condiciones higrotérmicas para las gallinas de postura en el estado de Oaxaca

Para el diseño pasivo y la ubicación de una granja avícola se requiere conocer el régimen térmico del ambiente y el de las gallinas de postura. Las condiciones extremas pueden ocasionar la muerte por estrés calórico a las aves además de una importante baja en la producción. El objetivo de este trabajo fue elaborar el análisis estadístico del polígono de confort horario de las gallinas de postura con base a el índice de temperatura y humedad (ITH), para los 9 bioclimas en el estado de Oaxaca. Inicialmente se recabaron datos bibliográficos para determinar la zona de confort térmico y los ITH óptimos. Posteriormente, se determinó que se cumple con los rangos propuestos por todos los autores para una mejor producción con los valores de temperatura de confort para las gallinas, en el rango entre 18 °C - 22 °C y humedad relativa entre 60% - 70%. Después se realizó un análisis horario de las condiciones higrotérmicas en las que se encuentra el ave mediante el cálculo del ITH horario. Los resultados muestran que las gallinas de postura presentan una condición higrotérmica de emergencia y de peligro durante el año en la siguiente proporción: bioclima cálido 20.14% en condición de emergencia y 32.99% en condición de peligro; bioclima cálido húmedo 4.86% en condición de emergencia y 38.54% en condición de peligro; bioclima cálido seco en 1.74% en condición de emergencia y 18.75% en condición de peligro.

World steel industry: changes in the regional structure and their effects for Ukraine (analytical overview)

Статья посвящена исследованию изменений и ведущих тенденций развития региональной структуры мировой металлургической промышленности по таким традиционным показателям, как объемы производства, сталеплавильных мощностей, потребления, экспорта и импорта металлопродукции. Актуальность проведения данного аналитического обзора объясняется различиями в условиях функционирования металлургии в разных странах и регионах мира, которые существенно влияют на основные результаты деятельности отрасли и определение оптимальных решений ее дальнейшего развития в контексте этих результатов.Выявлено, что в период 1997-2016 гг. произошло стремительное увеличение роли Азиатского региона по всем традиционным показателям. Бесспорное лидерство принадлежало Китаю, однако Индия, Индонезия, Филиппины, Пакистан, Вьетнам и Таиланд значительно нарастили присутствие на региональном и мировом металлорынках, в частности, в потреблении и импорте стальной продукции, а Южная Корея и Япония в основном сохранили свои позиции. Одни из самых высоких темпов роста металлургической промышленности в последнее двадцатилетие наблюдались на Ближнем Востоке и в Турции, тогда как в Африке и Южной Америке наиболее благоприятным периодом для развития отрасли были 2000-2007 гг. Одновременно произошло снижение роли стран ЕС, СНГ, Северной Америки и Океании. Эти регионы демонстрировали значительное падение производства в 2008-2016 гг., однако европейские и североамериканские государства преимущественно сохранили позиции ведущих потребителей и импортеров металлопродукции.Исследована географическая структура перепроизводства металла и выявлены регионы с постоянным дефицитом стальной продукции - Северная Америка, Ближний Восток, Африка. Акцентировано внимание на уровне загрузки сталеплавильных мощностей, повышение которого, при прочих равных условиях, могло бы решить проблему нехватки металлопродукции в данных регионах, однако этого не происходит вследствие существования ряда экономических, инновационных и социальных факторов.Определено, что позиции Украины на мировой арене как ведущего металлопроизводителя и экспортера в 2008-2016 гг. значительно ухудшились на фоне достаточно сдержанных ожиданий относительно роста спроса на металл на мировом рынке, повышения роли Азии и Ближнего Востока, которые традиционно были основными рынками сбыта для отечественных металлургов, и военных действий на Донбассе, которые привели к потере части металлургических мощностей. Ситуация усугубляется по причине катастрофически низкого уровня потребления металлопродукции на внутреннем рынке, следствием чего является постоянное перепроизводство металла и зависимость от внешнеэкономической конъюнктуры в условиях усиления конкуренции между лидерами отрасли вследствие увеличивающейся концентрации металлопроизводства.

Research Article Heat stress: impacts on fertility, productivity, and protein content of wheat cultivars

The aim of this study was to analyze the effects of high temperatures on ear fertility, yield components and protein content of wheat cultivars. Therefore, 96 genotypes were subjected to two environments in a greenhouse: control and heat stress. Each environment had two replicates, totalling 192 plots. The evaluations were: number of ear per plant, number of ear per pot, ear weight, number of grains per ear, number of sterile spikelet’s, number of viable grains, grain weight and protein content. Principal component analysis (PCA) and genetic and phenotypic correlations were performed. The results showed a significant drop in productivity of the genotypes subjected to heat stress as well as significant increase in the number of sterile spikelet’s. The PCA allowed the selection of nine promising genotypes for cultivation in environments with high temperatures with basis on these traits, especially the cultivars CD 104, CD 122 and TBIO Itaipu

Galantamine has impact on immunity in mice exposed to keyhole limpet hemocyanin.

In this work, we hypothesized whether galantamine could interact with the cholinergic anti-inflammatory pathway and modulate immunity this way. Galantamine is a drug used for the therapy of Alzheimer disease. The drug inhibits enzyme acetylcholinesterase in the central nervous system, which causes better availability of neurotransmitter acetylcholine. In the experiment, we immunized BALB/c laboratory mice by keyhole limpet hemocyanin (KLH) in combination with galantamine in a dose 0.02-0.5 mg/kg. The animals were sacrificed from 1 to 7 days after the substances applications and plasma was collected in order to examine immunochemical markers by enzyme-linked immunosorbent assay. We found significant drop in production of immunoglobulins and interleukin (IL) 4 level while IL2, IL4 and tumour necrosis factor α remained unaltered for the whole experiment. We infer that galantamine causes better availability of acetylcholine also in blood system, where the neurotransmitter interacts with nicotinic acetylcholine receptors on macrophages and initiates cholinergic anti-inflammatory pathway. In a conclusion, galantamine can cause lower efficacy of vaccination or immunity response to an infectious disease and the phenomenon should be taken into consideration in the current therapy (Tab. 1, Fig. 2, Ref. 24).

Cyclical and secular determinants of productivity in the copper, aluminum, iron ore, and coal industries

Over the past decade, both labor and multifactor productivity have fallen in copper, iron ore, coal, and many other mining operations, causing production costs to rise. This decline, following years of rising productivity, has led many to conclude that new technology can no longer offset the adverse effects of resource depletion. As a result, real mineral commodity prices will be permanently higher in the future. This article questions this hypothesis. It first provides a conceptual analysis that shows that much or perhaps even all of the recent drop in productivity could be due to the unanticipated growth in market demand and the sharp jump in prices it provoked. It then surveys a number of the available empirical studies of productivity trends. For copper, iron ore, and coal, it finds substantial support for the view that much of the recent drop in productivity can be attributed to higher prices. Aluminum on the other hand did not experience the same jump in real price over the 2000s nor did it suffer a significant drop in productivity. These findings have important implications. In particular, they suggest that new technology may well continue to offset most or all of the cost-increasing effects of resource depletion. If so, real commodity prices will be lower over the long run than many now assume. This possibility has important consequences for mineral-producing firms making large investments in future capacity, for mineral-producing countries dependent on revenues from mining, and for society as a whole in terms of the long-run availability of nonrenewable commodities and the future threat of mineral depletion.

WOLBACHIA INFECTION IN DROSOPHILA SIMULANS: DOES THE FEMALE HOST BEAR A PHYSIOLOGICAL COST?

Fitness traits of three Drosophila simulans strains infected by endocellular bacteria belonging to the genus Wolbachia have been compared with those of replicate stocks previously cured from the infection by an antibiotic treatment. The traits measured were development time, egg-to-adult viability, egg hatch, productivity, fecundity, and the number of functional ovarioles. Individuals of the first strain were bi-infected by two Wolbachia variants, wHa and wNo. The second strain was infected by wHa, the third one by wNo. The Wolbachia studied here cause cytoplasmic incompatibility (CI), a high embryonic mortality (70% to > 90%) when an infected male is crossed with an uninfected female. Three generations after antibiotic treatment, we observed in all strains a significant drop in productivity in the cured stocks. This drop was not due to antibiotic toxicity and was associated with the loss of the Wolbachia. However the effect had disappeared in two of the three strains five generations after treatment, and could not be found in the third strain in a third measurement carried out 14 generations after treatment. The temporary nature of the productivity difference indicates that Wolbachia do not enhance productivity in infected strains. On the other hand, in all traits measured, our results show the absence of any negative effects of the Wolbachia on their host. This could be explained when considering Wolbachia evolution, as maternally transmitted parasites bear a strong selective pressure not to harm their female host. However, CI would allow the bacteria to be maintained even when harming the female. The apparent absence of deleterious effects caused by these Wolbachia might result from a trade-off, where a relatively low bacteria density would advantage the Wolbachia by suppressing any deleterious effects on the female host, at the cost of a weaker maternal transmission rate of the infection.