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Long-chain omega-3 fatty acids—eicosapentaenoic and docosahexaenoic acids—are essential components of human diets and some aqua and animal feeds, but they are sourced from finite marine fisheries, and are in short supply and deficient in large parts of the world. We use quantitative systems analysis to model the current global eicosapentaenoic acid/docosahexaenoic acid cycle and identify options for increasing supply. Opportunities lie in increased by-product utilization and food waste prevention. However, economic, resource, cultural and technical challenges need to be overcome. Omega-3 fatty acids are important for the human diet and for some aqua and animal feeds. This study reports a supply gap, and using quantitative systems analysis identifies targets for increasing efficiency in the global omega-3 cycle.

Omega-3 EPA and DHA fatty acids are vital for human health, but current human nutritional requirements are greater than supply. This nutrient gap is poised to increase as demand increases and the abundance of aquatic foods and the amount of omega-3 they contain may dwindle due to climate change and overfishing. Identifying and mitigating loss and inefficiencies across the global aquatic supply chain has great potential for narrowing this nutrient gap. Here, using an optimization model, we show that omega-3 supply to humans could potentially increase by as much as 50% (reaching 630 kt y−1) compared to present baseline by shifting feed inputs to produce species that have the highest omega-3 content per feed input (i.e. carp and crustaceans), diverting other production flows towards direct wild fish consumption, improving byproduct utilization, and reducing waste at the retail and consumer level. We then discuss the implications of our findings by prioritizing policies and identifying demand- and supply-side interventions to realize these ambitious changes. This work emphasizes the urgency needed in managing aquatic resources towards greater utilization of resources and highlights the extent to which even partial adaptation of the measures we propose can have on narrowing the present and future nutrient gap as novel alternative sources of omega-3 become available on a larger scale.

The plant-availability of phosphorus (P) plays a central role in the ability of secondary P resources to replace mineral fertilizer. This is because secondary P plant-availability varies, often with large fractions of residual P that has no immediate fertilization effect. Therefore, if low quality secondary P fertilizers are applied, they will accumulate in soils that, in the long run, may increase the risk of P runoff and eutrophication. Substance flow analyses (SFA), used to identify potentials for improved P management, have not considered this well-known quality barrier. We, therefore, argue that traditional SFA over-estimates the fertilizer potential of secondary P resources. Using Norway as a case, we present a plant-availability extended SFA methodology that integrates SFA and the concept of relative agronomic efficiency. To account for the plant-available soil P stock and long-term soil interactions, we adjust the Norwegian P fertilization demand based on soil P values. We found that, while the method has uncertainties particularly for long-term estimations, it more realistically estimates secondary P fertilizer potentials and is adaptable to other countries. For Norway, we found the overall secondary P fertilizer potential reduced by 6-55% when considering plant-availability. The most important secondary resource was manure, which had the highest P plant-availability and quantities large enough (10.9kt plant-available P/yr) to meet Norway's entire P fertilization demand (5.8kt plant-available P/yr). However, barriers related to its transportability need to be overcome to efficiently use this resource. Fish sludge was also an important product, with 6.1kt plant-available P/yr but with uncertain plant-availability data. We argue that high quality secondary P resources can theoretically meet Norway's P fertilization demand and, therefore, make Norway mineral P independent. However, it is important that their use is carefully regulated based on plant-availability to eliminate the soil accumulation of both available and residual P.

Food waste (FW) generates large upstream and downstream emissions to the environment and unnecessarily consumes natural resources, potentially affecting future food security. The ecological impacts of FW can be addressed by the upstream strategies of FW prevention or by downstream strategies of FW recycling, including energy and nutrient recovery. While FW recycling is often prioritized in practice, the ecological implications of the two strategies remain poorly understood from a quantitative systems perspective. Here, we develop a multilayer systems framework and scenarios to quantify the implications of food waste strategies on national biomass, energy, and phosphorus (P) cycles, using Norway as a case study. We found that (i) avoidable food waste in Norway accounts for 17% of sold food; (ii) 10% of the avoidable food waste occurs at the consumption stage, while industry and retailers account for only 7%; (iii) the theoretical potential for systems-wide net process energy savings is 16% for FW prevention and 8% for FW recycling; (iv) the theoretical potential for systems-wide P savings is 21% for FW prevention and 9% for FW recycling; (v) while FW recycling results in exclusively domestic nutrient and energy savings, FW prevention leads to domestic and international savings due to large food imports; (vi) most effective is a combination of prevention and recycling, however, FW prevention reduces the potential for FW recycling and therefore needs to be prioritized to avoid potential overcapacities for FW recycling.

Summary Future phosphorus (P) scarcity and eutrophication risks demonstrate the need for systems-wide P assessments. Despite the projected drastic increase in world-wide fish production, P studies have yet to include the aquaculture and fisheries sectors, thus eliminating the possibility of assessing their relative importance and identifying opportunities for recycling. Using Norway as a case, this study presents the results of a current-status integrated fisheries, aquaculture, and agriculture P flow analysis and identifies current sectoral linkages as well as potential cross-sectoral synergies where P use can be optimized. A scenario was developed to shed light on how the projected 2050 fivefold Norwegian aquaculture growth will likely affect P demand and secondary P resources. The results indicate that, contrary to most other countries where agriculture dominates, in Norway, aquaculture and agriculture drive P consumption and losses at similar levels and secondary P recycling, both intra- and cross-sectorally, is far from optimized. The scenario results suggest that the projected aquaculture growth will make the Norwegian aquaculture sector approximately 4 times as P intensive as compared to agriculture, in terms of both imported P and losses. This will create not only future environmental challenges, but also opportunities for cross-sectoral P recycling that could help alleviate the mineral P demands of agriculture. Near-term policy measures should focus on utilizing domestic fish scrap for animal husbandry and/or fish feed production. Long-term efforts should focus on improving technology and environmental systems analysis methods to enable P recovery from aquaculture production and manure distribution in animal husbandry.

The insertion of central venous access devices for patients requiring all forms of central venous therapy is expensive and time consuming, particularly if general anesthetic and operating facilities are used by medical personnel, By expanding the role of a nurse who specialized in parenteral nutrition and who had previous experience in critical care, this procedure was able to be Performed Percutaneously at the bedside, cutting costs, freeing medical staff time, and improving patient care.

The insertion of central venous access devices for patients requiring all forms of central venous therapy is expensive and time consuming, particularly if general anesthetic and operating facilities are used by medical personnel, By expanding the role of a nurse who specialized in parenteral nutrition and who had previous experience in critical care, this procedure was able to be performed percutaneously at the bedside, cutting costs, freeing medical staff time, and improving patient care.

This study investigates the influence of ( a ) the surface form of complex sentences and ( b ) the appropriateness of the nouns which are subjects of the various clauses in these sentences for their respective verbs upon the comprehensibility of sentences. Base sentences cast as right-branching sentences are much more comprehensible than the same sentences cast in a center-embedded form. Furthermore, an intermediate case is intermediate in comprehensibility, and both the center-embedded and intermediate forms are sensitive to added clauses, while the right-branching form is not. Appropriateness of subject-noun and verb is a poor predictor of comprehensibility. These and earlier results lead to the conclusion that grammatical structure and not semantic relations is the major determiner of comprehensibility.

This study investigates the psychological correlates of linguistic marking in nouns, verbs, and adjectives covertly marked. Marked and unmarked forms are reliably differentiated by Ss naive with respect to the concept of markedness. The criteria used by Ss in such sorts appeared to be based upon an evaluative feature. Unmarked adjectives are reliably classed in a positive category and marked adjectives into a negative category. Unmarked (present tense) verbs and marked (past tense) verbs are reliably classed in positive and negative categories, respectively. Unmarked (singular) nouns are classed into positive categories and marked (plural) nouns into negative categories if the noun is semantically negative in meaning while the reverse is the case for semantically positive nouns. In addition, oppositional verbs not distinguished by criteria of marking were reliably categorized into positive and negative categories.

PREVIOUS STUDIES of the meristem in the Gramineae have given little attention to varietal differences and the influence of temperature in early development of the shoot. This study was undertaken to determine what ontogenetic differences are present in the early development of four varieties of Avena sativa and what effect temperature may have on the development of each variety. Four varieties including a brachitic dwarf were grown at 160C. and 280C. The size, structure, and form of the mature oat plant is controlled by the pattern of differentiation from the meristem during formative stages. Therefore a study of the meristem should be of value in understanding the morphology of the mature plant. All the leaves are initiated during the first 3 weeks in the four varieties growing at both high and low temperatures. At the high temperature, foliage development is somewhat more rapid and cell division, resulting in initiation of each new leaf primordia, is observed 2 or 3 days earlier than at the low temperature. The 3-week period of leaf initiation is considered the vegetative or formative period. Panicle differentiation follows rapidly after the initiation of all leaf primordia. At 28?C. panicle formation is inhibited. Thus environmental factors in the early stages have a determining effect on the mature plant. Varietal differences which are prominent in the mature stages are also apparent in the structural development of the shoot. MATERIALS AND METHODS.-Four varieties of Avena sativa were grown at constant temperatures of 160C. and 280C. in the Plant Pathology greenhouses at the University of Wisconsin during the period from November to January, 1945-1946. No artificial light was used. The plants were grown in 8-in. clay pots, fifteen grains being sown in each pot. The seed was obtained from the Cereal Division, Central Experimental Farm, Ottawa, Canada. The four varieties studied were Beacon, Dasix, Roxton, and Trelle's Dwarf. They were chosen to represent different growth habits and were known to vary in height and diameter of culms, in leaf and root development, and in maturity rates. The two early maturing varieties, Dasix and Beacon, provide a contrast in culm, leaf, and root development. Dasix has taller but smaller culms, narrower leaves, and less extensively developed adventitious roots than Beacon. Roxton is a tall, late variety with medium-sized culms. The brachitic dwarf variety, 1 Received for publication April 23, 1948. Part of a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at the University of Wisconsin. Acknowledgments are gratefully made to Dr. Emma L. Fisk for her helpful guidance throughout the study, to Dr. J. G. Dickson for his interest and suggestions, and to Mr. Eugene Herrling who took the photomicrographs. Trelle's Dwarf, usually grows only 18-24 in. high. The dwarf characteristic is apparent in internodal length but not in the size of leaves or diameter of culm. Under greenhouse conditions the plants of Beacon and Trelle's Dwarf remained erect while those of Roxton and Dasix lodged. Two plants from each variety, grown at two temperatures, were collected at 2or 3-day intervals. The last collection was made at the end of 58 days when differentiation of the panicle had begun. With the aid of a binocular dissecting microscope the older leaves were removed to assure more rapid and satisfactory fixation. In younger plants the coleoptile node and attached stem tip were fixed while in older plants only the portion above the third node was used. Embryos from soaked grains of each variety were fixed after being removed from the endosperm. Karpechenko's modification of Navashin's chromo-acetic-formalin fixative gave good results. The material was washed, dehydrated with etbyl alcohol, and run into paraffin by the cedarwood oil method. Sections were cut longitudinally at 10 . Most sections were stained with a weak Haidenhain's iron-alum haemotoxylin and safranin stain (Esau, 1944). Some sections were stained with fast green and safranin (Cross, 1937) and others with tannic acid, zinc chloride, orange G, and safranin (Sharman, 1943). OBSERVATION AND DISCUSSION.-Stages of growth from germination to panicle initiation.-The mature oat plant develops from an embryo in which the cotyledon, coleoptile, two foliage leaves, and the seminal root system are differentiated. The root system of the embryo includes the primary root, ensheathed in a coleorhiza, and usually one pair of lateral, seminal roots which are located below the cotyledonary node. Provascular strands are differentiated in the epicotyl and supply the cotyledon, coleoptile, and first leaf (Avery, 1930). Elongation of the first internode begins at germination and will eventually raise the second or coleoptile node to the ground level. One of the first changes observed at the time of germination is the initiation of the fifth leaf or the third leaf above the coleoptile by periclinal divisions of the dermatogen layer near the tip of the epicotyl (fig. 9). Throughout this study the cotvledon will be considered the first leaf and the coleoptile the second leaf. In median sections cut from embryos removed from grains soaked for 24 hr., recent division of the dermatogen layer indicates that the first step in initiation of a new leaf occurs very soon after planting. Mature oat plants usually have eight leaves, or six leaves above the coleoptile. Four leaves are initiated after germination and thus during the vegetative period of growth four plas

Most of the single-word responses to twoor three-word compound stimuli were nouns, whether the compounds were of adjectives or nouns. Content coding revealed that the responses to compound adjectives were positive or negative on the semantic feature 'evaluation' depending on whether the stimulus words had been unmarked or marked ones respectively. It is argued that marking and evaluation are correlated because marked words usually describe less usual states and that all associations have as their basis a semantically deep propositional structure in which the stimulus is the predicate and the response the subject.