| 31941. |
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| 31942. |
- Modig Johansson, Kajsa
(författare)
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Understanding Recycling Behavior – A Study of Motivational Factors behind Waste Recycling
- 2016
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Ingår i: 8th International Conference on Waste Management and the Environment. ; 202
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Globally, waste volumes are increasing rapidly and the World Bank estimates a 70% global increase in municipal solid waste until 2025. Waste may have serious environmental consequences and there is a strong correlation between solid waste generation rates and greenhouse gas emissions. These two observations alone indicate that this development is not sustainable. Recycling is one of the most important actions currently available to reduce the environmental impact of waste. While, waste recycling in OECD countries is reported to be approximately 22% on average, many developing countries have recycling rates in the range of 1-3%. A key aspect in succeeding with any recycling effort, is how authorities and other actors, relate to both informal and formal waste workers. This paper reports on the findings of a systematic literature study with the aim of exploring waste recycling behavior, with a special focus on motivational factors, both physical and psychological, behind recycling. Three levels of descending importance for recycling have been identified, where two are vital for success, and the third is desirable; 1) a well-designed infrastructure for recycling 2) specific recycling knowledge, and, 3) a general understanding of environmental aspects. Any attempt to implement or improve recycling systems and/or recycling behavior, needs to consider these aspects and the insights gained through this research may provide decision makers with practical assistance. The paper also contributes by providing academia with a framework for further studies on the behavioral aspects of recycling.
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| 31943. |
- Modig, Kristofer
(författare)
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Water and protein solutions studied by field-dependent magnetic relaxation
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the work presented, nuclear magnetic resonance (NMR) relaxation is used to study wide range of systems. The thesis concerns solvent interactions studied with relaxation techniques that involve measurements at many fields, which allows the separation of individual relaxation mechanisms. The approach also makes it possible to characterize the involved dynamic properties in much greater detail. The structure of liquid water is studied by investigating a hitherto unexploited relaxation mechanism for water protons, induced by the anisotropy of the chemical shielding tensor. By comparing the experimental results to theoretical calculations on the relation between water structure and the shielding tensor, it was possible to determine the hydrogen bond geometry over nearly the full temperature range of liquid water. The magnetic relaxation dispersion (MRD) technique carries the unique potential to directly monitor the solvent interactions with macromolecules. Here, the MRD of water was used to investigate the hydration of the large cavity found in the intra-cellular lipid-binding proteins. The about 20 water molecules within the cavity were found to exchange positions on the nanosecond time-scale, while exchanging with bulk water at least an order of magnitude slower. Upon ligand binding, the proteins expand their cavity volumes. Focusing on the solvent, MRD is very useful in studies of protein stability. Thus, equilibrium urea denaturation of intestinal fatty acid-binding protein (I-FABP) was followed by the MRD of both water and the denaturing agent. At least one water molecule binds to the protein in the presence of 7.5 M urea, where I-FABP appears denatured by conventional methods. The MRD data also suggest that the denatured state is much more compact than a fully solvated polypeptide. Similarly, the beta to alpha transition of beta-lactoglobulin (BLG) induced by trifluoroethanol (TFE) was investigated by the MRD of both water and TFE. The data indicate a preferential binding of TFE to the protein surface and demonstrate that BLG binds several long-lived (5-10 ns) TFE molecules in both states. During the transition, the protein expands and the TFE induced state consists of alpha-helical segments. Our data encourage the speculation that these segments are loosely tied together by TFE molecules (via dispersion forces) and water (via hydrogen bonds). Finally, the MRD method is compared to the use of intermolecular NOEs (nuclear Overhauser effect) between water and protein protons in studies of protein hydration. To focus on the surface hydration, we obtained the water MRD in deeply supercooled solutions of the peptide oxytocin and the globular protein BPTI. A large majority of the surface waters are dynamically retarded by only a factor of 2 as compared to bulk water. The NOE method frequently yields a retardation that is at least an order of magnitude longer. This inconsistency is removed by invoking a new model for the interpretation of NOE data, which shows that the NOEs of surface protein protons to water are dominated by long-range dipolar couplings.
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| 31944. |
- Modig, Sara
(författare)
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MANAGING DRUG USE IN THE ELDERLY. General practitioners’ adherence to guidelines and patients’ conceptions of medication
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Introduction: Older patients’ knowledge about their medicines is generally poor. Patients are entitled to be informed on an individual and adequate level. Evidence-based guidelines should, in most cases, be followed also in the treatment of elderly to avoid suboptimal treatment, for example for cardiovascular conditions, or risky prescriptions in the case of renal impairment. Objectives: 1. To describe frail elderly patients’ knowledge about and attitudes towards their medicines and to explore their experiences of receiving information about their medications. 2. To describe how well general practitioners (GPs) adhere to guidelines when using renal risk drugs in frail elderly patients and when treating elderly with cardio¬¬vascular disease and to evaluate local education of GPs as a tool for improvement. Methods: (Paper I, IV) For each prescribed medicine, the patient was asked about the indication and possible adverse effects. Attitudes were investigated with the Beliefs about Medicines Questionnaire. Semi-structured interviews covering questions on information about medication were analysed qualitatively. (Paper II) Medications for elderly patients in nursing homes were registered and the use of renal risk drugs was compared to renal function, estimated from s-creatinine and s-cystatin C. (Paper III) Data about GPs adherence to guidelines was collected from the medical records of patients aged ≥ 65 with a cardiovascular diagnosis. Local education was organized, followed by repeated measurements. Results: The knowledge about indication was satisfying but the knowledge about possible adverse effects was poor. The patients believed strongly in the benefits of their medication. The elderly felt comfortable with information when they trusted their physician or their medication, when they received enough information from the prescriber or when they knew how to find out sufficient information by themselves. They felt insecure if they were anxious, if the availability of medical care was poor or if they did not receive enough information. Reduced renal function was common (53%) in nursing home patients but s-creatinine was often normal. Renal risk drugs were rarely prescribed. The adherence to guidelines about cardiovascular diseases was low among GPs, but educational efforts appeared to increase the adherence. Conclusions: To receive an adequate drug therapy in the elderly, GPs should pay attention to patients’ need for suitable information on their medication and follow evidence-based guidelines about when to initiate and when to avoid certain drugs.
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| 31945. |
- Modig, Tobias
(författare)
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Efficient Conversion of Lignocellulose Hydrolysates- Yeast Tolerance and Redox Metabolism
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The fermentation of lignocellulose hydrolysates by Saccharomyces cerevisiae for ethanol production was investigated. An important problem for the successful conversion of these hydrolysates is that they often are inhibitory. The physiological effect of the furan inhibitors 5-hydroxymethyl furfural (HMF) and furfural were therefore studied, and based on the results novel strains were constructed. An additional problem for ethanol production is the by-product formation which reduces the ethanol yield. One major by-product during fermentation is glycerol, which is, furthermore, overproduced during hyperosmotic stress. Glycerol formation during anaerobic and hyperosmotic stress conditions was studied in the present work. It was shown that the enzymes alcohol dehydrogenase, aldehyde dehydrogenase and pyruvate dehydrogenase, all in the central carbon metabolism of S. cerevisiae, were strongly inhibited by furfural. The variability in S. cerevisiae strain response to lignocellulose hydrolysate was examined in both pulse addition and fed-batch experiments. Characterisation of the furan reduction capacity showed induced NADPH-coupled reduction for both furfural and HMF. A high constitutive NADH-coupled furfural reduction could also be seen. Based on the results of the characterisation of furan reduction, overexpression of the NADPH-dependent enzyme Adh6 and a NADH-dependent mutated Adh1 was conducted. For both enzymes, overexpression provided higher HMF conversion rate in defined medium and lignocellulose hydrolysate. Furthermore, the fermentation performance was improved in lignocellulose hydrolysate for both constructs. Glycerol formation serves to maintain the redox balance during anaerobic growth in S. cerevisiae and glycerol functions also as a osmolyte in hyperosmotic conditions. The response to combined hyperosmotic and anaerobic conditions were studied and large variations among strains could be seen. In addition, a previously uncharacterised protein (Yig1) was investigated for its possible role in regulating anaerobic glycerol formation. The overexpression of Yig1 was found to decrease the activity of glycerol-3-phosphatase.
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| 31946. |
- Modin Edman, Anna-Karin
(författare)
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Simulation of Phosphorus, Zinc and Cadmium Mass Flow in Dairy Farming Systems
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A simulation model, FARMFLOW, was developed for the calculation of phosphorus (P), zinc (Zn) and cadmium (Cd) stocks, flows and balances in different parts of a dairy farming system. The simulated continuous change in element stocks within the farming system enables evaluation of the long-term effects of management practices. The FARMFLOW model reproduces feedback mechanisms of the internal cycling of nutrients and trace elements between crops and animals on the dairy farm in feed and manure. In addition, FARMFLOW reproduces the balancing feedbacks in the system, consisting of export of elements in milk, crops and animals as well as losses from the soil system. Field data from a case study at the Swedish experimental farm Öjebyn were used to parameterise FARMFLOW. At Öjebyn, organic and conventional management practices were run in parallel over 12 years. Simulations were made over 6 crop rotations, i.e. 36 years. The simulated effects of the management practices on the stocks, flows and balances of P, Zn and Cd are presented for the organic farming system (OFS) and for the conventional farming system (CFS) at Öjebyn. The simulated field-specific element accumulation rates were mainly governed by the difference in manure application rate between the fields, arising from differences in field size, and by differences in losses between the fields, arising from differences in the initial elemental content of the fields. Simulations with increasing animal density in the two management systems showed that FARMFLOW is useful in predicting the impact of intensification on, e.g. the manure P application rates. Annual variations in mass flows, e.g. yields, and element concentrations were observed at the Öjebyn farm. In order to evaluate the impact on the element stocks, flows and balances of variations in the system, FARMFLOW was parameterised with input data including these variations. For P, the variations generated moderate variations in the farm gate P balances, and the variations did not cause a shift in the balances around the policy target of zero. For Zn, it was shown that even the highest simulated accumulation rates of the two systems did not cause soil Zn concentrations risking adverse effects on soil fertility in a 36 year perspective. For Cd, the variations can lead to up to 20% higher removal of Cd in harvested crops than average values.
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| 31947. |
- Modin, Hanna, et al.
(författare)
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Lab Scale Simulation of a Leak in a Landfill Cover
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Many Swedish landfills are currently applied with a final cover. To minimise costs and the use of natural resources, waste materials can be a suitable substitute in landfill covers. Depending on the wastes’ contents, their mobility and in which layer of the final cover they are used, they could potentially contribute to the emission potential of the landfill. In this study the impact on landfill leachate quality from the drainage water of a final cover is investigated. Part of a landfill and its cover, below the upper drainage layer, was simulated in lab scale: The simulated liner was constructed from a mixture of fibre and ash residues from paper pulp production and the foundation and gas drainage layer was simulated by bottom ash from a municipal solid waste incinerator. The waste below the liner was simulated by residues from sorting of construction and demolition waste. The leachate from the simulated damaged landfill cover had elevated concentrations of many substances including metals, ions and organic matter. However, the simulated landfilled waste could sorb several of these. Ag, Cd, Cu, Hg, N, P, Pb and Sb were sorbed to such an extent that the effect from the cover leachate was unnoticeable. The only pollutants that passed through the waste unattenuated were As, K, Na, TOC, V and Zn. In a real landfill the sorption would be even better since the waste mass will be much larger compared to the cover. Despite elevated concentrations of potentially complex forming substances there was no evidence that the cover leachate enhanced the leaching of any contaminants from the waste. Altogether the results show that the use of the studied waste materials in landfill covers can only be expected to have a small effect on the concentration of contaminants in the leachate from the landfill.
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| 31948. |
- Modin, Hanna, et al.
(författare)
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Leaching test using samples from a modern, carbon-poor landfill
- 2011
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Ingår i: [Host publication title missing].
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Landfilling of organic waste is prohibited in Sweden. Modern Swedish landfills differ from landfills containing municipal solid waste rich in organic matter. As a first step to understanding long-term leaching from modern landfills, a leaching test was performed. The leaching of heavy metals was small compared to the total contents. At a liquid to solid ratio of 10 more than 99 % of most heavy metals remained in the waste. The degradation potential measured as respiration during four days was below 1 mg O2•g-1 dry waste and it decreased during the leaching. Due to the low degradability of this waste it does not seem motivated to keep the landfill moist to enhance degradation during the active phase. The contaminants of concern in a modern landfill are largely non-degradable, e.g. heavy metals, and they must be disposed of somewhere once removed from the leachate. A reasonable management option, therefore, could be to keep the landfill as dry as possible in an attempt to keep the metals in the landfill for as long time as possible.
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| 31949. |
- Modin, Hanna
(författare)
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Modern landfill leachates – quality and treatment
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Waste management in Europe has changed, mainly as a result of stricter regulations, most notably the European Landfill Directive 1999/31/EC. In Sweden, landfill tax and a ban on the landfilling of waste with total organic carbon content over 10 % have diverted large amounts of waste from landfills. The biogeochemistry of landfills has changed due to their reduced organic content. The research presented in this thesis aimed at improving understanding of leachate quality in modern landfills. Biodegradation and leaching tests were employed on wastes typical of a waste manage¬ment system shifting away from landfilling. Multivariate data analysis using principal component analysis and canonical correlation analysis was employed to identify processes governing leachate quality and relations between leachate parameters. As heavy metals are expected to be relatively more pronounced in modern landfills, sorption to granular activated carbon, bone meal and iron fines was evaluated as a means of removing heavy metals from leachate. The main difference in two leachates from landfills with less than 10 % organic carbon in the waste in relation to leachates from older landfills containing municipal solid waste was the extremely low ammonium content. Very low dissolved organic carbon content was also observed. Leaching of heavy metals in the same order of magnitude as in MSW landfills was observed in modern landfills. The results further indicate that a certain degradation potential must be expected, even in the carbon poor wastes deposited in modern landfills. Therefore reducing conditions will be likely to occur in the landfills. Although landfill gas formation will be low, degradation is likely to significantly affect the biogeochemical conditions, thus affecting metal leaching and rendering it relatively similar to that in municipal solid waste landfills. However, since the amounts of biodegradable organic matter are smaller they will be depleted sooner than in municipal solid waste landfills. As a result, the long term differences may be greater. The multivariate data analysis identified variation in the concentration of salts as the most important process governing leachate quality. This variation had various causes, including dilution, depletion and varying input materials. Redox potential was also identified as an important process. In the cases where samples were taken before and after treatment, the effect of the treatment strongly influenced the results. All the sorption materials studied had the potential to remove heavy metals, but none was effective against all the metals in the leachate. They also all had the drawback of releasing unwanted substances into the leachate. This illustrates the importance of site-specifically evaluating all treatments and analysing a large number of substances in the leachates, not just those targeted by the treatment. The main pollutants to be expected in modern landfills with only small amounts of organic matter will probably be inorganic, e.g. heavy metals. While the organic matter emitted by older landfills can be changed into more or less inert forms, metals can never be destroyed, just concentrated, diluted or moved to another medium. Enhancing biodegradation and flushing pollutants by allowing water to infiltrate into landfills is advocated as a sustainable management option for municipal solid waste landfills. However, in the case of mainly inorganic landfills, containment aimed at keeping the metals in the landfills for as long as possible rather than dispersing them into the environment might be a better option.
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| 31950. |
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