Global Phosphorus Flows in the Industrial Economy From a Production Perspective

Human activity has quadrupled the mobilization of phosphorus (P), a nonrenewable resource that is not fully recycled biologically or industrially. P is accumulated in both water and solid waste due to fertilizer application and industrial, agricultural, and animal P consumption. This paper characterizes the industrial flows, which, although smaller than the agricultural and animal flows, are an important phosphorus source contributing to the pollution of surface waters. We present the quantification of the network of flows as constrained by mass balances of the global annual metabolism of phosphorus, based on global consumption for 2004, all of which eventually ends up as waste and in the soil and water systems. We find that on a yearly basis, 18.9 million metric tons (MMT) of P is produced, of which close to 75% goes to fertilizer and the rest to industrial and others uses. Phosphoric acid is the precursor for many of the intermediate and end uses of phosphate compounds described in this study and accounts for almost 80% of all P consumed. Eventually, all of the P goes to waste: 18.5 MMT ends up in the soil as solid waste, and 1.32 MMT is emissions to air and water. Besides quantifying P flows through our economy, we also consider some possible measures that could be taken to increase the degree of recovery and optimization of this resource and others that are closely related, such as the recovery of sulfur from gypsum and wastewater (sludge), and fluorine from wet phosphoric acid production.     

Mapping the Global Distribution of Livestock

Livestock contributes directly to the livelihoods and food security of almost a billion people and affects the diet and health of many more. With estimated standing populations of 1.43 billion cattle, 1.87 billion sheep and goats, 0.98 billion pigs, and 19.60 billion chickens, reliable and accessible information on the distribution and abundance of livestock is needed for a many reasons. These include analyses of the social and economic aspects of the livestock sector; the environmental impacts of livestock such as the production and management of waste, greenhouse gas emissions and livestock-related land-use change; and large-scale public health and epidemiological investigations. The Gridded Livestock of the World (GLW) database, produced in 2007, provided modelled livestock densities of the world, adjusted to match official (FAOSTAT) national estimates for the reference year 2005, at a spatial resolution of 3 minutes of arc (about 5×5 km at the equator). Recent methodological improvements have significantly enhanced these distributions: more up-to date and detailed sub-national livestock statistics have been collected; a new, higher resolution set of predictor variables is used; and the analytical procedure has been revised and extended to include a more systematic assessment of model accuracy and the representation of uncertainties associated with the predictions. This paper describes the current approach in detail and presents new global distribution maps at 1 km resolution for cattle, pigs and chickens, and a partial distribution map for ducks. These digital layers are made publically available via the Livestock Geo-Wiki (http://www.livestock.geo-wiki.org), as will be the maps of other livestock types as they are produced.     

Increased Efficiency of Transgenic Livestock Production

Production of transgenic livestock by pronuclear microinjection of DNA into fertilized zygotes suffers from the compounded inefficiencies of low embryo survival and low integration frequencies of the injected DNA into the genome. These inefficiencies are one of the major obstacles to the large-scale use of pronuclear microinjection techniques in livestock. We investigated exploiting the properties of recombinase proteins that allow them to bind DNA to generate transgenic animals via pronuclear microinjection. In theory, the use of recombinase proteins has the potential to generate transgenic animals with targeted changes, but in practice we found that the use of RecA recombinase-coated DNA increases the efficiency of transgenic livestock production. The use of RecA protein resulted in a significant increase in both embryo survival rates and transgene integration frequencies. Embryo survival rates were doubled in goats, and transgene integration was 11-fold higher in goats and three-fold higher in pigs when RecA protein-coated DNA was used compared with conventional DNA constructs without RecA protein coating. However, a large number of the transgenic founders generated with RecA protein-coated DNA were mosaic. The RecA protein coating of DNA is straightforward and can be applied to any species and any existing microinjection apparatus. These findings represent significant improvements on standard pronuclear microinjection methods by enabling the more efficient production of transgenic livestock.     

The Influence of Phytoplankton Primary Production on the Cycle of Biogenic Elements in the Coastal Waters off Sevastopol,Black Sea

The phytoplankton primary production and the biogenic elements content of the coastal waters off Sevastopol have been studied as a result of 2-year monitoring. It has been found that mineral phosphorus is a key factor of chemical limitation of the production processes. During primary production of organic matter, the habitat conditions for phytoplankton in the photic layer are in accordance with the Le Chatelier–Braun principle of negative feedback.     

Market Movements: Nongovernmental Organization Strategies to Influence Global Production and Consumption

This article analyzes nongovernmental organization (NGO) market campaigns that seek to motivate changes in global consumption and production patterns. Through campaigns targeting products as diverse as paper, shoes, and computers, advocacy groups seek to use existing concerns of consumers to influence producers, and simultaneously, to expand and deepen consumer demand for more sustainable products and services. NGOs deploy both negative information to critique leading brands, and positive information to help build new markets for improved products. Successful market campaigns construct networks of actors that identify points of leverage within global production and trading regimes; coordinate research, exposure, direct action, and negotiations with brands; identify solutions; advance new multi-stakeholder standards and monitoring and certification schemes; build new nongovernmental regulatory institutions; and occasionally attempt to strengthen state regulation. Through an assessment of three market campaigns focused on Staples, Nike, and Dell, this article describes the nature of these campaigns, discusses how they function, assesses their central strategies and tactics, and analyzes whether they are actually having an impact. The article concludes by discussing the relevance and implications of these campaigns for the field of industrial ecology, and how industrial ecology might support future efforts to advance more sustainable production and consumption.     

The Influence of Study Schedules and Work on the Sleep-Wake Cycle of College Students

College students usually exhibit an irregular sleep-wake cycle characterized by great phase delays on weekends and short sleep length on weekdays. As the temporal organization of social activities is an important synchronizer of human biological rhythms, we investigated the role played by study's schedules and work on the sleep-wake cycle. Three groups of female college students were investigated: (1) no-job morning group, (2) no-job evening group, (3) job evening group. The volunteers answered a sleep questionnaire in the classroom. The effects of day of the week and group on the sleep schedules and sleep length were analyzed by a two way ANOVA for repeated measures. The three groups showed delays in the wake up time on weekends. No-job evening and morning groups also delayed bedtime, but the job evening group slept at the same time on weekdays as on weekends. Sleep length increased on weekends for morning group and job evening group, whereas the no-job evening group maintained the amount of sleep from weekdays to weekends. This survey showed that the tendency of phase delay on weekends was differently expressed according to study's schedules and work.     

Livestock Herbivory Shapes Fire Regimes and Vegetation Structure Across the Global Tropics

Ecosystems - Livestock grazing is the most extensive human land use and one of the key drivers of the conversion of tropical forests into grasslands. Livestock effects on vegetation structure are...     

The Influence of the Global Gene Expression Shift on Downstream Analyses

The assumption that total abundance of RNAs in a cell is roughly the same in different cells is underlying most studies based on gene expression analyses. But experiments have shown that changes in the expression of some master regulators such as c-MYC can cause global shift in the expression of almost all genes in some cell types like cancers. Such shift will violate this assumption and can cause wrong or biased conclusions for standard data analysis practices, such as detection of differentially expressed (DE) genes and molecular classification of tumors based on gene expression. Most existing gene expression data were generated without considering this possibility, and are therefore at the risk of having produced unreliable results if such global shift effect exists in the data. To evaluate this risk, we conducted a systematic study on the possible influence of the global gene expression shift effect on differential expression analysis and on molecular classification analysis. We collected data with known global shift effect and also generated data to simulate different situations of the effect based on a wide collection of real gene expression data, and conducted comparative studies on representative existing methods. We observed that some DE analysis methods are more tolerant to the global shift while others are very sensitive to it. Classification accuracy is not sensitive to the shift and actually can benefit from it, but genes selected for the classification can be greatly affected.     

Impacts of Pathogen Introduction Risk on Importer Behavior and Gains from Trade in the Livestock Industry

Trade eliminates geographic barriers, allowing for novel exchange of goods and services, but also creates pathways for the unintentional spread of infectious pathogens such as foot and mouth disease. In the absence of trade regulation, a producer’s choice of import origin depends on relative prices and costs associated with trading partners. This paper develops a framework for exploring importer behavior in a non-regulated economy, allowing for price and risk heterogeneity among potential import sources. In the model, importers determine the risk of introducing foot and mouth disease to home soil and choose import volumes using risk and market data. When importers consider the possibility of unreported or undetected outbreaks, they choose to import from multiple sources to minimize risk and simultaneously create gains from trade over the regulated outcome. Our results have implications for the development of import and inspection policies that could be specifically designed to target highest risk imports of livestock.     

光合作用与农业生产

光合作用被誉为是地球上最重要的化学反应,没有光合作用就不可能有人类社会的产生和发展。光合作用是作物产量形成的物质基础,如何充分利用太阳能进行光合作用是农业生产中的一个根本性问题。文章从作物光能利用率与光合作用效率、光合作用过程及其运转的调控、农业发展动向与高光效三个方面简要分析了光合作用与农业生产的关系,以期为今后的相关研究提供一些思考。     

Using Random Forest to Improve the Downscaling of Global Livestock Census Data

Large scale, high-resolution global data on farm animal distributions are essential for spatially explicit assessments of the epidemiological, environmental and socio-economic impacts of the livestock sector. This has been the major motivation behind the development of the Gridded Livestock of the World (GLW) database, which has been extensively used since its first publication in 2007. The database relies on a downscaling methodology whereby census counts of animals in sub-national administrative units are redistributed at the level of grid cells as a function of a series of spatial covariates. The recent upgrade of GLW1 to GLW2 involved automating the processing, improvement of input data, and downscaling at a spatial resolution of 1 km per cell (5 km per cell in the earlier version). The underlying statistical methodology, however, remained unchanged. In this paper, we evaluate new methods to downscale census data with a higher accuracy and increased processing efficiency. Two main factors were evaluated, based on sample census datasets of cattle in Africa and chickens in Asia. First, we implemented and evaluated Random Forest models (RF) instead of stratified regressions. Second, we investigated whether models that predicted the number of animals per rural person (per capita) could provide better downscaled estimates than the previous approach that predicted absolute densities (animals per km²). RF models consistently provided better predictions than the stratified regressions for both continents and species. The benefit of per capita over absolute density models varied according to the species and continent. In addition, different technical options were evaluated to reduce the processing time while maintaining their predictive power. Future GLW runs (GLW 3.0) will apply the new RF methodology with optimized modelling options. The potential benefit of per capita models will need to be further investigated with a better distinction between rural and agricultural populations.     

Animal Welfare and Livestock Production in a Postindustrial Milieu

Structural transformation, food safety, and environmental risks pose challenges to livestock producers. Adjustments to livestock production systems to improve animal welfare will be made in an economic and political milieu characterized by these challenges. However, competing assumptions about contemporary society provide different frameworks for formulating the problems faced by industry and government decision makers. The assumption that industrialization is the key problem in livestock production leads to an application of science that does not adequately address the role of public participation and trust.     

Effect of Phosphorus on the Synechococcus Cell Cycle in Surface Mediterranean Waters during Summer

The effect of phosphorus (P) and nitrogen (N) additions on the Synechococcus cell cycle was tested with natural populations from the Mediterranean Sea in summer. In the absence of stimulation, the Synechococcus cell cycle was synchronized to the light-dark cycle. DNA synthesis began around 1600, a maximum of S-phase cells was observed at around dusk (2100), and a maximum of G(inf2)-phase cells was observed at around 2400. Addition of P (as PO(inf4)(sup3-)) caused, in all cases, a decrease in the fraction of cells in G(inf2) at around 1800, no change at around 2400, and an increase at around 1200 the next day, while addition of N (as NO(inf3)(sup-)) had no effect. We hypothesize that P addition induced a shortening of the G(inf1) phase, resulting in cells entering and leaving the S and G(inf2) phases earlier. These data suggest very strongly that the Synechococcus cells were P limited rather than N limited during this period of the year. In most cases, additions as low as 20 nM P induced a cell cycle response. From dose-response curves, we established that the P concentration inducing a 50% change in the percentage of cells in G(inf2) was low, close to 10 nM, at the beginning of the sampling period (30 June) and increased to about 50 nM by the end (9 July), suggesting a decrease in the severity of P limitation. This study extends recent observations that oligotrophic systems may be P rather than N limited at certain times of the year.     

Perpetual Phosphorus Cycling: Eutrophication Amplifies Biological Control on Internal Phosphorus Loading in Agricultural Reservoirs

Nearly half of US lakes are impaired, primarily resulting from excessive nutrients and resultant eutrophication. The stability and recycling of sediment P results in differing degrees of internal P loading, which can alter lake water quality. In this study, we asked: (1) What are the underlying mechanisms controlling internal loading (net release) and retention of P? and (2) How does trophic state, specifically a hypereutrophic condition, affect internal P loading in agricultural reservoirs? We show that shifts in internal P loading are related to trophic-level indicators, including total P (TP) and chl-a concentrations. All study reservoirs were classified as hypereutrophic, and we grouped them as “less eutrophic” or “more eutrophic” based on TP and chl-a concentrations. In less eutrophic lakes, chemical variables (for example, oxygen) and sediment iron-bound P primarily controlled internal P loading under anaerobic conditions. However, in the more eutrophic lakes, biological variables, including phytoplankton biomass (as indicated by chl-a concentrations) and extracellular enzyme activity, drove internal P loading or reduced P retention under aerobic conditions. Biologically controlled aerobic internal P cycling was related to higher sediment organic P pools being broken down by enzymatic hydrolysis. Therefore, we theorize that as lakes become hypereutrophic, biological mechanisms begin to amplify internal P release by acting under both anaerobic and aerobic conditions, thus creating a perpetual cycle of internal P loading. Thus, the role of biological processes and oxygen availability should be considered in water quality management strategies aimed at alleviating eutrophication in lakes.     

From START to FINISH: The Influence of Osmotic Stress on the Cell Cycle

The cell cycle is a sequence of biochemical events that are controlled by complex but robust molecular machinery. This enables cells to achieve accurate self-reproduction under a broad range of different conditions. Environmental changes are transmitted by molecular signalling networks, which coordinate their action with the cell cycle. The cell cycle process and its responses to environmental stresses arise from intertwined nonlinear interactions among large numbers of simpler components. Yet, understanding of how these pieces fit together into a coherent whole requires a systems biology approach. Here, we present a novel mathematical model that describes the influence of osmotic stress on the entire cell cycle of S. cerevisiae for the first time. Our model incorporates all recently known and several proposed interactions between the osmotic stress response pathway and the cell cycle. This model unveils the mechanisms that emerge as a consequence of the interaction between the cell cycle and stress response networks. Furthermore, it characterises the role of individual components. Moreover, it predicts different phenotypical responses for cells depending on the phase of cells at the onset of the stress. The key predictions of the model are: (i) exposure of cells to osmotic stress during the late S and the early G2/M phase can induce DNA re-replication before cell division occurs, (ii) cells stressed at the late G2/M phase display accelerated exit from mitosis and arrest in the next cell cycle, (iii) osmotic stress delays the G1-to-S and G2-to-M transitions in a dose dependent manner, whereas it accelerates the M-to-G1 transition independently of the stress dose and (iv) the Hog MAPK network compensates the role of the MEN network during cell division of MEN mutant cells. These model predictions are supported by independent experiments in S. cerevisiae and, moreover, have recently been observed in other eukaryotes.     

Influence of Agricultural By-products in Liquid Culture on Chlamydospore Production by the Potential Mycoherbicide Fusarium oxysporum Foxy 2

Economically feasible inoculum mass production methods are required for successful application of Fusarium oxysporum Foxy 2 as a potential mycoherbicide. Therefore, different substrates (agricultural by-products) and the factors that influence the production of spores, especially chlamydospores, of Foxy 2 were investigated in liquid cultures. The substrates tested were cotton seed cake, maize stover, wheat and triticale stillage. The presence of plant fibers in the medium of unfiltered cotton seed cake (2.5%, w/v) significantly enhanced chlamydospore, micro- and macroconidia production by 150, 185, and 300%, respectively, compared to the filtered (fiber-free) medium. Regardless of the type of substrate tested, Foxy 2 was able to produce abundant chlamydospores (0.14-2.7×10⁷ mL^-1) in all growth media. Generally, increasing the concentrations of cotton seed cake and maize stover in the medium significantly increased chlamydospore formation; however, this was not the case for wheat-based stillage. To optimize conditions required for chlamydospore production of Foxy 2, the effect of near ultra-violet (NUV) light, substrate combinations (synergism), level of agitation, incubation time and their interaction were studied. A liquid culture of 2.5% (w/v) filtered cotton seed cake, exposed to continuous NUV for 15 days, doubled the yield of chlamydospores (4.7×10⁶ mL^-1) and macroconidia (5×10⁵ mL^-1), and increased microconidial production by one-third (1×10⁸ mL^-1) compared to natural light. An apparent synergistic effect of substrate combination was observed, since the addition of 20% (v/v) of either wheat or triticale-based stillage to maize stover medium (1%, w/v) increased the number of chlamydospores produced by 16 or 12 times, respectively, compared to maize stover alone (1.4×10⁶ mL^-1), and 2 times more than either of the stillages. A significantly positive effect between a high level of agitation tested during incubation and chlamydospore production of Foxy 2 was recorded. All in all, substantial chlamydospore production of Foxy 2 (4.3×10⁷ mL^-1) was successfully achieved within 12 days of incubation in a single-step liquid fermentation through the combination of 0.5% (w/v) maize stover plus 20% (v/v) wheat-based stillage and a high level of agitation (200 rpm).