| 1. |
- Arshamian, Artin, et al.
(author)
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A mammalian blood odor component serves as an approach-avoidance cue across phylum border - from flies to humans
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Journal article (peer-reviewed)abstract
- Chemosignals are used by predators to localize prey and by prey to avoid predators. These cues vary between species, but the odor of blood seems to be an exception and suggests the presence of an evolutionarily conserved chemosensory cue within the blood odor mixture. A blood odor component, E2D, has been shown to trigger approach responses identical to those triggered by the full blood odor in mammalian carnivores and as such, is a key candidate as a food/alarm cue in blood. Using a multidisciplinary approach, we demonstrate that E2D holds the dual function of affecting both approach and avoidance behavior in a predator-prey predicted manner. E2D evokes approach responses in two taxonomically distant blood-seeking predators, Stable fly and Wolf, while evoking avoidance responses in the prey species Mouse. We extend this by demonstrating that this chemical cue is preserved in humans as well; E2D induces postural avoidance, increases physiological arousal, and enhances visual perception of affective stimuli. This is the first demonstration of a single chemical cue with the dual function of guiding both approach and avoidance in a predator-prey predicted manner across taxonomically distant species, as well as the first known chemosignal that affects both human and non-human animals alike.
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| 2. |
- Baraibar Norberg, Matilda, 1979-
(author)
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The Political Economy of Agrarian Change in Latin America : Argentina, Paraguay and Uruguay
- 2020
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Book (peer-reviewed)abstract
- This book makes an original contribution to the discussion about agro-food exporting countries’ governmental policy. It presents a historicized and internationally contextualized exploration of the political economy of agrarian change in three Latin American countries: Argentina, Praguay, and Uruguay. By comparatively examining how these states have acted in a context of global driven market forces and historically formed institutions, the monograph illuminates the differing capacities of state autonomy under the present era of globalized agriculture.
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| 3. |
- Baraibar Norberg, Matilda, 1979-, et al.
(author)
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The Soybean Through World History : Lessons for Sustainable Agrofood Systems
- 2023
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Book (peer-reviewed)abstract
- This book examines the changing roles and functions of the soybean throughout world history and discusses how this reflects the complex processes of agrofood globalization.The book uses a historical lens to analyze the processes and features that brought us to the current global configuration of the soybean commodity chain. From its origins as a peasant food in ancient China, today the protein-rich soybean is by far the most cultivated biotech crop on Earth; used to make a huge variety of food and industrial products, including animal feed, tofu, cooking oil, soy sauce, biodiesel and soap. While there is a burgeoning amount of literature on how the contemporary global soy web affects large tracts of our planet’s social-ecological systems, little attention has been given to the questions of how we got here and what alternative roles the soybean has played in the past. This book fills this gap and demonstrates that it is impossible to properly comprehend the contemporary global soybean chain, or the wider agrofood system of which it is a part, without looking at both their long and short historical development. However, a history of the soybean and its changing roles within equally changing agrofood systems is inexorably a history about globalization. Not only does this book map out where soybeans are produced, but also who governs, wields power and accumulates capital in the entire commodity chain from inputs in production to consumption, as well as identifying the institutional context the global commodity chain operates within. The book concludes with a discussion of the main challenges and contradictions of the current soy regime that could trigger its rupture and end.This book is essential reading for students, practitioners and scholars interested in agriculture and food systems, global commodity chains, globalization, environmental history, economic history and social-ecological systems.
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| 4. |
- Beal, Jacob, et al.
(author)
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Robust estimation of bacterial cell count from optical density
- 2020
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In: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Journal article (peer-reviewed)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 5. |
- Erlandsson, Martin, et al.
(author)
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A comparison of MAGIC and paleolimnological predictions of preindustrial pH for 55 Swedish lakes.
- 2008
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In: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 42:1, s. 43-8
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Journal article (peer-reviewed)abstract
- Two fundamentally different approaches to define reference conditions for acidification assessments are hydrogeochemical modeling and paleolimnological reconstructions. Both methods have been applied to calculate the preindustrial chemistry for 55 Swedish lakes in two independent studies. This paper investigates whether these methods give similar reconstructions of the preindustrial pH for these lakes. Special focus has been attached to the importance of total organic carbon concentrations and CO2 partial pressure (pCO(2)) in the conversion from ANC to pH in the hydrogeochemical modeling. With a uniform pCO(2) value for all the lakes of 0.63 matm, the mean absolute difference between pH from the hydrogeochernical model and the paleolimnological pH was +0.23 units (mean absolute difference 0.36 units). If instead a lake specific preindustrial pCO(2) is assumed, equal to contemporary pCO(2), the mean difference in the predicted preindustrial pH between the two methods was reduced to +0.03 units (mean absolute difference 0.22 units). Statistical analyses indicated that with a lake specific pCO(2), the difference between the reconstructions is smaller than 0.13 pH-units at a 95% level of significance. The results of this study build confidence in the reliability of both methods, providing that lake-specific estimates of pCO(2) are used.
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| 6. |
- Norberg, Matilda, 1977-
(author)
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A paleolimnological perspective on liming – implications for defining reference conditions in Swedish lakes
- 2009
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Doctoral thesis (other academic/artistic)abstract
- Using paleolimnological techniques, I have studied surface-water acidification and the effects of liming in Swedish lakes on a decadal to millennial time-scale. The overall objective was to contribute to the discussion on the fulfilment of goals within the Swedish liming program. One of the main goals of this program is to restore lakes to natural or nearly natural conditions, i.e. to a reference condition as termed in the EU Water Framework Directive. In this context, a key issue is to define reference conditions. This is a central theme of my thesis, as lake sediments offer a unique way to study past lake conditions. Past lake-water acidity of 12 reference lakes in the Swedish liming program (ISELAW) was determined using diatom analysis of sediment cores. Pollen, lead, and flyash from coal/oil combustion were used as indicators of impact from land use and atmospheric pollution. A general trend in these lakes is an initial decline in pH after lake formation due to natural soil processes, which was then followed by rather low pH values (pH 5.3-6.5). In six of the lakes pH increased as a result of expansion of agriculture (burning, forest grazing) 2000 to 1000 years ago. Local mining and long-range airborne pollution have also impacted the lakes since medieval time. These results show that the conditions of the study lakes were not natural prior to industrialization and recent (20th century) acidification. The ISELAW lakes were selected on the basis of representing typical limed lakes, and they have been limed and monitored since at least the 1980s. A comparison of chemical/biological monitoring data and the paleolimnological data gives somewhat diverging results. Most of the monitoring data suggest that the lakes were subjected to acidification during the 20th century, but the paleolimnological data can only identify clear evidence of acidification in five of the 12 lakes, hence, all lakes were probably not recently acidified. According to conclusions from monitoring the lakes have recovered following liming. The paleolimnological data give a more complex picture and three different responses have been identified: 1) a return to a diatom composition found in the lake one hundred to several thousand years ago; 2) very small shifts in the diatom composition; or 3) a diatom composition previously not found in the lake. The latter response raised the question whether liming can cause an unnatural diatom community. A comparison of diatoms in surface sediment samples of 31 limed lakes with pre-industrial reference samples from 291 lakes showed that liming does not create an unnatural diatom composition. These results illustrate that the goals for liming were not reached in all of the limed lakes, and that paleolimnology can play an important role for assessments of acidification and liming. The comparative study also highlights the importance of designing monitoring programs that can produce reliable and long data series. Given the results of the paleolimnological investigations, it is obvious that we cannot assume that the 19th century represented a natural or near natural state, and thus is a realistic reference conditions. Natural long-term lake development and previous land-use impacts need to be considered in defining reference conditions. Neither can we disregard the fact that humans always will impact nature. Although paleolimnological studies are time consuming, I believe that they could be simplified to the extent that paleolimnology could become a routine method for environmental management.
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| 7. |
- Norberg, Matilda, et al.
(author)
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Comparing pre-industrial and post-limed diatom communities in Swedish lakes, with implications for defining realistic management targets
- 2010
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In: Journal of Paleolimnology. - : Springer. - 0921-2728 .- 1573-0417. ; 44:1, s. 233-242
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Journal article (peer-reviewed)abstract
- In the 1960s and 1970s, acidification was identified as a major environmental problem in Scandinavia, Great Britain and North America. In Sweden, a liming program was launched in order to counteract the effects of acidification on surface waters. More than 30 years after large-scale liming began, there is still debate about whether liming actually achieves its goals, i.e., to prevent acidification in acid-sensitive surface waters and to restore natural conditions in acidified waters. We used Detrended Correspondence Analysis (DCA) and analogue matching of diatom assemblages in surface sediment samples (recent conditions) from 31 limed lakes and pre-industrial samples from 291 reference lakes to help answer the question as to whether the Swedish liming program achieves its goals. Diatoms are important primary producers in lakes and established indicator organisms for lake-water quality. First we compared pre-industrial with post-limed diatom communities to address the question whether liming causes unnatural conditions, i.e., diatom communities that have not previously occurred in Swedish lakes. Second, we addressed the issue of what is a realistic condition to use as a reference (natural condition) or a target in management programs. We found that the diatom communities in limed lakes were not different from the communities in the reference lakes. Most of the limed lakes had one or more analogues within the reference data set and many of them had at least one within-lake analogue. Hence, liming does not create unique diatom communities in lakes. Based on this and previous paleolimnological studies in Swedish lakes we suggest a conceptual model integrating the natural lake condition, the historical human impact, and the recent and contemporary human impact, when defining realistic targets in management programs.
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| 8. |
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| 9. |
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| 10. |
- Norberg, Matilda, et al.
(author)
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Monitoring compared with paleolimnology : implications for the definition of reference condition in limed lakes in Sweden.
- 2008
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In: Environmental Monitoring & Assessment. - : Springer Science and Business Media LLC. - 0167-6369 .- 1573-2959. ; 146:1-3, s. 295-308
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Journal article (peer-reviewed)abstract
- Surface water acidification was identified as a major environmental problem in the 1960s. Consequently, a liming program was launched in Sweden in the 1970s. The primary purpose of liming is to restore conditions that existed prior to acidification. To reach this goal, as well as achieve ‘good status' (i.e. low levels of distortion resulting from human activity) in European freshwaters until 2016 under the European Union Water Framework Directive, lake data are required to define reference conditions. Here, we compare data from chemical/biological monitoring of 12 limed lakes with results ofpaleolimnological investigations, to address questions of reference conditions, acidification, and restoration by liming. Using diatom-based lake-water pH inferences, we found clear evidence of acidification in only five of the 12 lakes, which had all originally been classified as acidified according to monitoring data. After liming, measured and diatom-inferred pH agree well in seven lakes. The sediment record of three of the five remaining lakes gave ambiguous results, presumably due to sediment mixing or low sediment accumulation rates. It is difficult to determine whether liming restored the lakes to a good status, especially as some of the lakes were not acidified during the twentieth century. In addition to acid deposition, other factors, such as natural lake and catchment ontogeny or human impact through agricultural activity, influence lake acidity. This study shows that monitoring series are usually too short to define reference conditions for lakes, and that paleolimnological studies are useful to set appropriate goals for restoration and for evaluation of counter measures.
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