Thermal disinfection of seawater for aquacultural purpose     

Pl Jacobsen  Helge Liltved 《Aquacultural Engineering》1988,7(6):443-447

The dose of heat required to kill Vibrio anguillarum has been determined. The results show that > 99·97% inactivation was obtained after 3 min exposure to 44·0°C. After 2 min exposure to 47·5°C, > 99·99% inactivation was obtained. The results indicate that heating is a useful method for safe disinfection of small amounts of water.  相似文献   

Understanding root,tuber, and banana seed systems and coordination breakdown: a multi-stakeholder framework     

Jeffery W. Bentley  Jorge Andrade-Piedra  Paul Demo  Beloved Dzomeku  Kim Jacobsen  Enoch Kikulwe 《Journal of Crop Improvement》2018,32(5):599-621

Vegetatively propagated crop (VPC) seed tends to remain true to varietal type but is bulky, often carries disease, and is slow to produce. So VPC seed needs to be handled differently than that of other crops, e.g., it tends to be sourced locally, often must be fresh, and it is less often sold on the market. Hence, a framework was adapted to describe and support interventions in such seed systems. The framework was used with 13 case studies to understand VPC seed systems for roots, tubers, and bananas, including differing roles and sometimes conflicting goals of stakeholders, and to identify potential coordination breakdowns when actors fail to develop a shared understanding and vision. In this article, we review those case studies. The framework is a critical tool to (a) document VPC seed systems and build evidence; (b) diagnose and treat coordination breakdown and (c) guide decision-makers and donors on the design of more sustainable seed system interventions for VPCs. The framework can be used to analyze past interventions and will be useful for planning future VPC seed programs.  相似文献   

High-EPA Biomass from Nannochloropsis salina Cultivated in a Flat-Panel Photo-Bioreactor on a Process Water-Enriched Growth Medium     

Hamed Safafar  Michael Z. Hass  Per M?ller  Susan L. Holdt  Charlotte Jacobsen 《Marine drugs》2016,14(8)

Nannochloropsis salina was grown on a mixture of standard growth media and pre-gasified industrial process water representing effluent from a local biogas plant. The study aimed to investigate the effects of enriched growth media and cultivation time on nutritional composition of Nannochloropsis salina biomass, with a focus on eicosapentaenoic acid (EPA). Variations in fatty acid composition, lipids, protein, amino acids, tocopherols and pigments were studied and results compared to algae cultivated on F/2 media as reference. Mixed growth media and process water enhanced the nutritional quality of Nannochloropsis salina in laboratory scale when compared to algae cultivated in standard F/2 medium. Data from laboratory scale translated to the large scale using a 4000 L flat panel photo-bioreactor system. The algae growth rate in winter conditions in Denmark was slow, but results revealed that large-scale cultivation of Nannochloropsis salina at these conditions could improve the nutritional properties such as EPA, tocopherol, protein and carotenoids compared to laboratory-scale cultivated microalgae. EPA reached 44.2% ± 2.30% of total fatty acids, and α-tocopherol reached 431 ± 28 µg/g of biomass dry weight after 21 days of cultivation. Variations in chemical compositions of Nannochloropsis salina were studied during the course of cultivation. Nannochloropsis salina can be presented as a good candidate for winter time cultivation in Denmark. The resulting biomass is a rich source of EPA and also a good source of protein (amino acids), tocopherols and carotenoids for potential use in aquaculture feed industry.  相似文献   

Lipids and Composition of Fatty Acids of Saccharina latissima Cultivated Year-Round in Integrated Multi-Trophic Aquaculture     

Gon?alo S. Marinho  Susan L. Holdt  Charlotte Jacobsen  Irini Angelidaki 《Marine drugs》2015,13(7):4357-4374

This study is evaluating the seasonal lipid and fatty acid composition of the brown seaweed Saccharina latissima. Biomass was sampled throughout the year (bi-monthly) at the commercial cultivation site near a fish farm in an integrated multi-trophic aquaculture (IMTA) and at a reference site in Denmark (2013–2014). Generally, there was no difference in the biomass composition between sites; however, significant seasonal changes were found. The lipid concentration varied from 0.62%–0.88% dry weight (DW) in July to 3.33%–3.35% DW in November (p < 0.05) in both sites. The fatty acid composition in January was significantly different from all the other sampling months. The dissimilarities were mainly explained by changes in the relative abundance of 20:5n-3 (13.12%–33.35%), 14:0 (11.07%–29.37%) and 18:1n-9 (10.15%–16.94%). Polyunsaturated fatty acids (PUFA’s) made up more than half of the fatty acids with a maximum in July (52.3%–54.0% fatty acid methyl esters; FAME). This including the most appreciated health beneficial PUFA’s, eicosapentaenoic (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), but also arachidonic (ARA) and stearidonic acid (SDA), which are not found in land vegetables such as cabbage and lettuce. Compared to fat (salmon) and lean fish (cod) this seaweed species contains higher proportions of ARA and SDA, but lower EPA (only cod) and DHA. Conclusively, the season of harvest is important for the choice of lipid quantity and quality, but the marine vegetables provide better sources of EPA, DHA and long-chain (LC)-PUFA’s in general compared to traditional vegetables.  相似文献   

Multiple measurements constrain estimates of net carbon exchange by a Eucalyptus forest     

H. Keith  R. Leuning  K.L. Jacobsen  H.A. Cleugh  E. van Gorsel  R.J. Raison  B.E. Medlyn  A. Winters  C. Keitel 《Agricultural and Forest Meteorology》2009,149(3-4):535-558

Net ecosystem exchange of carbon (F_NEE) was estimated for a temperate broadleaf, evergreen eucalypt forest ecosystem at Tumbarumba in south-eastern Australia to investigate the processes controlling forest carbon sinks and their response to climate. Measurements at a range of temporal and spatial scales were used to make three different estimates of F_NEE based on: (1) the difference between fluxes of carbon input by photosynthesis and output by autotrophic plus heterotrophic respiration, (2) changes over time in the carbon pools in the above- and below-ground biomass, soil and litter, and (3) micrometeorological flux measurements that provide a continuous estimate of the net exchange. A rigorous comparison of aggregated component fluxes and the net eddy fluxes within a flux tower source area was achieved based on an inventory of the site and a detailed sampling strategy. Measurements replicated in space and time provided mean values, confidence limits and patterns of variation of carbon pools and fluxes that allowed comparisons within known limits of uncertainty. As a result of comparisons between nighttime eddy flux and chamber measurements of respiration, a revised micrometeorological method was developed for estimating nighttime carbon flux using flux tower measurements. Uncertainty in the final estimate of F_NEE was reduced through mutual constraints of each of these measurement approaches. F_NEE for the period October 2001–September 2002, with average rainfall, was an uptake of 6.7 (5.1–8.3) tC ha^?1 yr^?1 estimated from component fluxes, and 5.4 (3.0–7.5) tC ha^?1 yr^?1 estimated from the revised eddy flux method. Biomass increment was 4.5 (3.7–5.4) tC ha^?1 yr^?1 and the remaining 0.9–2.2 tC ha^?1 yr^?1 could represent a carbon sink in the soil and litter pools or lie within the confidence limits of the measured fluxes. F_NEE was reduced to ?0.1 to 2.4 tC ha^?1 yr^?1 during a period of drought and insect disturbance in October 2002–September 2003, with biomass increment being the main component reduced. The forest is a large carbon sink compared with other forest ecosystems, but this is subject to high-annual variability in response to climate variability and disturbance.  相似文献   

Antisnake Venom Production Crisis—Who Told Us It Was Uneconomic and Unsustainable?     

Ian D. Simpson  Ingrid M. Jacobsen 《The Forestry Chronicle》2009,20(2):144-155

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Moving integrated weed management from low level to a truly integrated and highly specific weed management system using advanced technologies          下载免费PDF全文

S L Young  S K Pitla  F K Van Evert  J K Schueller  F J Pierce 《Weed Research》2017,57(1):1-5

Integrated weed management (IWM) is one of the most commonly referred to approaches for sustainable and effective weed control in agriculture, yet it is not widely practiced, likely because current IWM systems fail to meet performance expectations of growers. The effectiveness and value of IWM systems should increase with increasing application specificity and true integration made possible with contemporary advances in technology, information systems and decision support. IWM systems can be classified based on their degree of application specificity and level of integration of tactics. In the application specificity pathway, a tactic is applied at a range of scales, from subfield to plant specific. In the integration pathway, multiple weed control tactics are combined in a synergistic manner. We hypothesise that the full value of IWM can and will be realised only when current and emerging technological innovations, information systems and decision tools are synergistically combined for use in real time. The True IWM system we envision requires automation and robotic technologies, coupled with information and decision support systems that are available or emerging but not yet enabled, in a proven integrated platform. Examples of low‐level, traditional and precision IWM systems are discussed, and research needs for a True IWM system are presented. We conclude that the immediate call should be for a long‐term investment in R&D and education (both theoretical and empirical) to develop and implement True IWM systems, an effort best accomplished in a public–private partnership where all essential entities are fully engaged and adequately resourced, including growers from all countries who will utilise IWM.  相似文献   

Epigenetic reprogramming in plant and animal development   总被引：1，自引：0，他引：1  

Feng S  Jacobsen SE  Reik W 《Science (New York, N.Y.)》2010,330(6004):622-627

Epigenetic modifications of the genome are generally stable in somatic cells of multicellular organisms. In germ cells and early embryos, however, epigenetic reprogramming occurs on a genome-wide scale, which includes demethylation of DNA and remodeling of histones and their modifications. The mechanisms of genome-wide erasure of DNA methylation, which involve modifications to 5-methylcytosine and DNA repair, are being unraveled. Epigenetic reprogramming has important roles in imprinting, the natural as well as experimental acquisition of totipotency and pluripotency, control of transposons, and epigenetic inheritance across generations. Small RNAs and the inheritance of histone marks may also contribute to epigenetic inheritance and reprogramming. Reprogramming occurs in flowering plants and in mammals, and the similarities and differences illuminate developmental and reproductive strategies.  相似文献   

The potato breeding programme in Denmark     

Børge Jacobsen 《Potato Research》1958,1(1):21-24

Summary Frem 1948 onward there has been a marked increase in potato breeding work in Denmark. This is due to the fact that the Danish Agriculture Potato Fund was established in this year and its proceeds are devoted to the advancement of potato breeding in Denmark. The fund owns the Potato Breeding Station at Vandel, near Vejle, and this together with the State Research Station at Tylstrup are the only places in Denmark where potato breeding is carried out. Breeding of ware varieties constitutes a great part of the work, although the breeding of varieties used for fodder and industrial purposes is also an important aspect of the work. The quality and yield capacity of the new varieties are very important considerations, although the present work of breeding also aims at finding varieties which are only slightly affected by late blight and common scab. As the conditions governing the production of virus-free seed potatoes, do not constitute any serious problem in Denmark, little attention has been paid to the finding of virus-resistant varieties, except on the case of special varieties intended for export. The station in Vandel owns a fairly large collection of wild and cultivated species of potatoes. Three of the most promising varieties from Vandel will be sent for an official test as from 1958.

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Zusammenfassung Seit dem Jahre 1948 ist die Arbeit der Kartoffelzüchtung in D?nemark ganz bedeutend erweitert worden, da in diesem Jahre der ?Kartoffelfonds der Landwirtschaft? gegründet wurde, dessen Ertrag in erster Linie die Kartoffelzüchtung D?nemarks stützen soll. Der Fonds besitzt die Zuchtstation bei Vandel. Zusammen mit der Versuchsstation in Tylstrip im Besitz des Staates, ist es die einzigen Stelle in D?nemark, wo Kartoffelzüchtung betrieben wird. Die Züchtung von Speisekartoffeln ist sehr wichtig, aber auch die Arbeit mit Futter- und Fabrikkartoffeln ist von gr?sster Bedeutung. Eigenschaften, wie Ertrag und Qualit?t der neuen Kartoffelsorten, sind von besonderer Wichtigkeit, aber eines der Ziele der jetzigen Züchtungsarbeit ist, Kartoffelsorten zu finden, die nicht so stark von Krautf?ule und Kartoffelschorf angegriffen werden. Da die Bedingungen für die Erzeugung von virusfreien Saatkartoffeln in D?nemark sehr günstig sind, hat man nicht viel Interesse daran, virusresistente Sorten zu züchten, mit Ausnahme von Kartoffelsorten für Export. Auf der Station in Vandel befindet sich eine gr?ssere Sammlung von wilden und kultiviertenSolanum-Arten, die einer der Mitarbeiter der Station aus verschiedenen südamerikanischen Staaten mitgebracht hat. Drei neue Sorten haben bei den vorl?ufigen Prüfungen gute Resultaten ergeben.

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Résumé A partir de l'année 1948 l'ocuvre sélectionnaire de la pomme de terre au Danemark a pris un large essor. C'est que dans cette année fut institutée la ?Caisse Agricole de la Pomme de terre?, dont les fonds sont réservés en premier lieu à soutenir l'oeuvre sélectionnaire de la pomme de terre au Danemark. La ?Caisse? exploite la Station d'expérimentation à Vandel qui, ensemble avec la Station d'essais à Tylstrup-également un institut de l'Etat-sont les seules institutions au Danemark où l'on se voue à l'oeuvre sélectionnaire de la pomme de terre. La culture de la pomme de terre de consommation revêt une importance particulière, tout comme d'ailleurs celle des pommes de terre fourragères et industrielles. Les propriétés des nouvelles variétés, telles que rendement et qualité, sont très importantes, mais l'un des objectifs de l'oeuvre sélectionnaire de nos jours est de créer des variétés de pommes de terre résistantes au mildiou et à la gale commune. Etant donné que les conditions de production pour plants de pommes de terre exempts de toute contagion virologique sont très favorables au Danemark, on s'intéresse peu à la culture de variétés résistantes aux maladies à virus, sauf les variétés de pommes de terre destinées à l'exportation. A la Station à Vandel on dispose d'une collection assez riche de variétésSolanum sauvages et cultivées en provenance de différents états américains et approtées par l'un des chercheurs de cet Institut. Trois variétés ont fait l'objet d'expériences entreprises à titre provisoire, et elles ont donné de bons résultats.

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Lecture held at Lund, August 1957  相似文献   

Near infrared spectra indicate specific mutant endosperm genes and reveal a new mechanism for substituting starch with (1→3,1→4)-β-glucan in barley     

L. Munck  B. Mller  S. Jacobsen  I. Sndergaard 《Journal of Cereal Science》2004,40(3):125

Near Infrared Reflectance spectroscopy was tested as a screening method to characterise high lysine mutants from a barley collection by classification through Principal Component Analysis (PCA). Mean spectra of the samples within each cluster identified gene-specific patterns in the 2270–2360 nm region. The characteristic spectral signatures representing the lys5 locus (Risø mutants 13 and 29) were found to be associated with large changes in percentage of starch and (1→3,1→4)-β-glucan. These alleles compensated for a low level of starch (down to 30%) by a high level of (1→3,1→4)-β-glucan (up to 15–20%), thus, maintaining a constant production of polysaccharides at 50–55%, within the range of normal barley.The spectral tool was tested by an independent data set with six mutants with unknown polysaccharide composition. Spectral data from four of these were classified within the high (1→3,1→4)-β-glucan BG lys5 cluster in a PCA. Their high (1→3,1→4)-β-glucan and low starch content was verified. It is concluded that genetic diversity such as from gene regulated polysaccharide and storage protein pathways in the endosperm tissue can be discovered directly from the phenotype by chemometric classification of a spectral library, representing the digitised phenome from a barley gene bank.  相似文献