| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)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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| 2. |
- Braide, Anna, 1964, et al.
(författare)
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Debatt – Hög tid för socialt bostadsbyggande.
- 2017
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Ingår i: Tidskriften Plan - Planering av stad och land.. - 0032-0560. ; :2017/4, s. 46-47
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Ericsson, Morgan, 1973, et al.
(författare)
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Mining Job Ads to find what skills are sought after from an employers' perspective on IT graduates
- 2014
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Ingår i: ITICSE 2014 - Proceedings of the 2014 Innovation and Technology in Computer Science Education Conference. - New York, New York, USA : ACM Press. - 9781450328333 ; , s. 354-
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Konferensbidrag (refereegranskat)abstract
- We mine job ads to discover what skills are required from an employers' perspective. Some obvious trends appear, such as skills related to web and mobile technology. We aim to uncover more detailed information as the study continues to allow course content to better match the expressed needs. Categories and Subject Descriptors K.3.2 [Computers and Education]: Computer and Information Science Education General Terms Data mining.
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| 4. |
- Johansson, Kristin, 1979, et al.
(författare)
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Environmental impact of the EPSPEX system. Part 1: Life cycle assessment of polystyrene insulated district heating systems with PEX fluid pipes
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The EPSPEX system is a distribution system for district heat with media pipes of cross-linked polyethylene (PEX) insulated by blocks of expanded polystyrene (EPS). In this low-pressure distribution system two pipes are used for a space heating circuit, having layers of EVAL to hinder oxygen diffusion, whereas two pipes without diffusion barrier are used for delivery of hot tap water and warm water circulation. The four pipes are placed in the insulating blocks of EPS. Environmental impacts from production, laying and use of an EPSPEX district heat distribution system have been investigated using life cycle methodology. The distribution system is a secondary system developed specially for areas with low heat density. The case studied is the installation and use of an EPSPEX system in Vråen, Värnamo, Sweden. The environmental impacts are described in four categories:climate change, acidification, eutrophication and use of finite resources. Four weighting methods have also been used in the evaluation: EPS2000, Ecoscarcity, ExternE and EcoIndicator99. While carefully considering the precise circumstances of this study, the findings can be adapted for using the EPSPEX district heat distribution systems in other areas.During this study the question was raised of how this district heat delivery system compares with systems that use conventional district heating pipes. This has beenfurther investigated and is reported in the second part of this report: Miljöbelastning från EPSPEX-systemet. Del 2: Konventionella twinrör eller EPSPEX vad är bäst urmiljösynpunkt. In the second part the environmental impacts from the EPSPEX system have been compared with the impacts from conventional twin pipes (polyurethane insulated steel media pipes) used in a comparable setting. A discussion on the environmental choice between media pipes of PEX and steel can also be found in the second part. It should be noted that the two systems for district heat distribution are not fully comparable in function. The EPSPEX system has stricter limitations regarding pressure and temperature compared with the conventional system. The EPSPEX system is also limited in use for well drained ground conditions above the water table. Conventional district heating pipes do not have this limitation. The most important possibility to decrease the environmental impacts from the EPSPEX system is to increase the insulation, this even though the distribution systemis comparably well insulated to start with. The environmental life cycle impacts of the distribution pipe system production, laying and use are predominated by the extra heat that has to be generated to cover the heat losses from the system. When this report was written, measurements from systems in use to confirm the model calculation of heat losses are still lacking. More fine-tuned results can be achieved when studies of the EPSPEX system in use have been concluded.Among different components in the EPSPEX system the impacts from production and transport of EPS-blocks make the major impact. Thus, it is important to utilize the polystyrene material as efficiently as possible, minimizing spillage, and to ensure that unavoidable spillage is recycled as material. However, the environmental impacts from production of the insulating blocks are well outweighed by the decreased environmental impacts gained by using the insulation. In product development it is thus important to ensure that the insulating capacity of the EPSPEX system is never decreased.Machines used for excavating the pipe trenches combust diesel oil, and the production and use of this diesel oil generates a substantial part of the environmental impacts byseveral of the assessment methods used. If possible, it is desirable to further minimize the excavation work and to use mini excavators and low emitting machines (especially regarding nitrous oxides). The brass swaged coupling used to connect the PEX-pipes, gives a strong impact regarding acidification and the two weighting methods EPS2000 and Ecoscarcity, especially when compared to the very small volume fraction these devices constitute. It would be advisable to study if the devices could be made from other material or from recycled material.
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| 5. |
- Johansson, Kristin, 1979, et al.
(författare)
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Environmental impact of the EPSPEX system. Part 2: Traditional twin pipes or EPSPEX for district heat distribution - what is best from an environmental point of view?
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In this study the life-cycle environmental impacts from an EPSPEX system for distribution of district heat (a four-pipe system with centrally generated hot tap water) are compared with the environmental impacts of a twin-pipe system with steel media pipes, if installed in the same area. A life cycle assessment of the EPSPEX system constructed in Vråen, Värnamo, Sweden, has been reported in Miljöbelastning från EPSPEX-systemet. Del 1: Livscykelanalys av polystyrenisolerat fjärrvärmesystemmed PEX-mediarör [1]. In that study the question was raised of how the EPSPEX system compares with a conventional twin-pipe system with polyurethane-insulated steel media pipes.In the present study the EPSPEX system in Vråen is compared with a hypothetical construction of a conventional twin pipe system in the same area. Two different fuel mixes for district heat generation have been studied to increase the understanding of the environmental performance of district heat distribution systems; the fuel mix used in Vråen (heat delivered from Värnamo Energi) and Swedish average district heat. How media pipes from the two different materials (PEX and steel) compare is discussed in a separate part. There are technical differences that must be kept in mind when the systems are compared in this way. The EPSPEX system is designed for low-pressure district heat systems and could only be used in such context. It is unadvisable to install the EPSPEX system below the ground water table; this is not a restriction for the twin pipe system. Under the conditions of this study the environmental performance of the EPSPEX system is better than the twin pipe system.The heat loss from the EPSPEX system is approximately 60% of the heat loss for a comparable twin pipe system. This is caused by a combination of thick insulation for the EPSPEX system and the possibility to summertime shut down the district heating circuit for this system and only use the hot tap-water circuit. Note, however, that the heat loss from the EPSPEX system is more uncertain compared to the twin-pipe system. From the characterization methods used, the production of the EPSPEX system gives a higher environmental impact compared to the twin pipe system. This heavily depends on the large amount of insulating material used. However, the environmental impacts from production of the insulation are more then outweighed by the emissionsavoided from heat generation due to lower heat loss. District heating sub centrals generates a notable part of the total environmental impact when using the weighing method EPS2000. Note that sub centrals are not technicallynecessary in low-pressure district heat systems, as the EPSPEX system. The comparison between different fuel mixes for heat generation indicates clearly that the heat generation is an important parameter for environmental performance for all district heating. It is further indicated that also biofuels must be used with sensible andenvironmentally friendly methods. The media pipes of PEX seem to give lower environmental impacts compared withmedia pipes of steel. However, the results differ between assessment methods used.
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| 8. |
- Olsson, Tobias, 1974-, et al.
(författare)
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Evaluation of a static architectural conformance checking method in a line of computer games
- 2014
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Ingår i: QoSA '14 Proceedings of the 10th international ACM Sigsoft conference on Quality of software architectures. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450325769 ; , s. 113-118
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Konferensbidrag (refereegranskat)abstract
- We present an evaluation of a simple method to find architectural problems in a product line of computer games. The method uses dependencies (direct, indirect, or no) to automatically classify types in the implementation to high-level components in the product line architecture. We use a commercially available tool to analyse dependencies in the source code. The automatic classification of types is compared to a manual classification by the developer, and all mismatches are reported. To evaluate the method, we inspect the source code and look for a pre-defined set of architectural problems in all types. We compare the set of types that contained problems to the set of types where the manual and automatic classification disagreed to determine precision and recall. We also investigate what changes are needed to correct the found mismatches by either designing and implementing changes in the source code or refining the automatic classification. Our evaluation shows that the simple method is effective at detecting architectural problems in a product line of four games. The method is lightweight, customisable and easy to implement early in the development cycle.
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| 9. |
- Stanaway, Jeffrey D., et al.
(författare)
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Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990-2017: A systematic analysis for the Global Burden of Disease Study 2017
- 2018
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Ingår i: The Lancet. - 1474-547X .- 0140-6736. ; 392:10159, s. 1923-1994
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Tidskriftsartikel (refereegranskat)abstract
- Background The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 comparative risk assessment (CRA) is a comprehensive approach to risk factor quantification that offers a useful tool for synthesising evidence on risks and risk-outcome associations. With each annual GBD study, we update the GBD CRA to incorporate improved methods, new risks and risk-outcome pairs, and new data on risk exposure levels and risk- outcome associations. Methods We used the CRA framework developed for previous iterations of GBD to estimate levels and trends in exposure, attributable deaths, and attributable disability-adjusted life-years (DALYs), by age group, sex, year, and location for 84 behavioural, environmental and occupational, and metabolic risks or groups of risks from 1990 to 2017. This study included 476 risk-outcome pairs that met the GBD study criteria for convincing or probable evidence of causation. We extracted relative risk and exposure estimates from 46 749 randomised controlled trials, cohort studies, household surveys, census data, satellite data, and other sources. We used statistical models to pool data, adjust for bias, and incorporate covariates. Using the counterfactual scenario of theoretical minimum risk exposure level (TMREL), we estimated the portion of deaths and DALYs that could be attributed to a given risk. We explored the relationship between development and risk exposure by modelling the relationship between the Socio-demographic Index (SDI) and risk-weighted exposure prevalence and estimated expected levels of exposure and risk-attributable burden by SDI. Finally, we explored temporal changes in risk-attributable DALYs by decomposing those changes into six main component drivers of change as follows: (1) population growth; (2) changes in population age structures; (3) changes in exposure to environmental and occupational risks; (4) changes in exposure to behavioural risks; (5) changes in exposure to metabolic risks; and (6) changes due to all other factors, approximated as the risk-deleted death and DALY rates, where the risk-deleted rate is the rate that would be observed had we reduced the exposure levels to the TMREL for all risk factors included in GBD 2017.
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