| 1. |
- Al Khatib, Iyad, 1975-
(author)
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Performance Analysis of Application-Specific Multicore Systems on Chip
- 2008
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Doctoral thesis (other academic/artistic)abstract
- The last two decades have witnessed the birth of revolutionary technologies in data communications including wireless technologies, System on Chip (SoC), Multi Processor SoC (MPSoC), Network on Chip (NoC), and more. At the same time we have witnessed that performance does not always keep pace with expectations in many services like multimediaservices and biomedical applications. Moreover, the IT market has suffered from some crashes. Hence, this triggered us to think of making use of available technologies and developing new ones so that the performance level is suitable for given applications and services. In the medical field, from a statistical viewpoint, the biggest diseases in number of deaths are heart diseases, namely Cardiovascular Disease (CVD) and Stroke. The application with the largest market for CVD is the electrocardiogram (ECG/EKG) analysis. According to the World Health Organization (WHO) report in 2003, 29.2% of global deaths are due to CVD and Stroke, half of which could be prevented if there was proper monitoring. We found in the new advance in microelectronics, NoC, SoC, and MPSoC, a chance of a solution for such a big problem. We look at the communication technologies, wireless networks, and MPSoC and realize that many projects can be founded, and they may affect people's lives positively, as for example, curing people more rapidly, as well as homecare of such large scale diseases. These projects have a medical impact as well as economic and social impacts. The intention is to use performance analysis of interconnected microelectronic systems and combine it with MPSoC and NoC technologies in order to evolve to new systems on chip that may make a difference. Technically, we aim at rendering more computations in less time, on a chip with smaller volume, and with less expense. The performance demand and the vision of having a market success, i.e. contributing to lower healthcare costs, pose many challenges on the hardware/software co-design to meet these goals. This calls upon the development of new integrated circuits featuring increased energy efficiency while providing higher computation capabilities, i.e. better performance. The biomedical application of ECG analysis is an ideal target for an application-specific SoC implementation. However, new 12-lead ECG analyses algorithms are needed to meet the aforementioned goals. In this thesis, we present two novel algorithms for ECG analysis, namely the Autocorrelation-Function (ACF) based algorithm and the Fast Fourier Transform (FFT) based algorithm. In this respect, we explore the design space by analyzing different hardware and software architectures. As a result, we realize a design with twelve processors that can compute 3.5 million arithmetic computations and respect the real time hard deadline for our biomedical application (3.5-4seconds), and that can deploy the ACF-based and FFT-based algorithms. Then, we investigate the configuration space looking for the most effective solution, performance and energy-wise. Consequently, we present three interconnect architectures (Single Bus, Full Crossbar, and Partial Crossbar) and compare them with existing solutions. The sampling frequencies of 2.2 KHz and 4 KHz, with 12 DSPs, are found to be the critical points for our Shared-Bus design and Crossbar architecture, respectively. We also show how our performance analysis methods can be applied to such a field of SoC design and with a specific purpose application in order to converge to a solution that is acceptable from a performance viewpoint, meets the real-time demands, and can be implemented with the present technologies while at the same time paving the way for easier and faster development. In order to connect our MPSoC solution to communication networks to transmit the medical results to a healthcare center, we come up with new protocols that will allow the integration of multiple networks on chips in a communication network. Finally, we present a methodology for HW/SW Codesign for application-specific systems (with focus on biomedical applications) that require a large number of computations since this will foster the convergence to solutions that are acceptable from a performance point of view.
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| 2. |
- An, Junxue, et al.
(author)
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Nanoscale characterization of PEGylated phospholipid coatings formed by spray drying on silica microparticles
- 2020
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In: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 577, s. 92-100
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Journal article (peer-reviewed)abstract
- Phospholipids constitute biocompatible and safe excipients for pulmonary drug delivery. They can retard the drug release and, when PEGylated, also prolong the residence time in the lung. The aim of this work was to assess the structure and coherence of phospholipid coatings formed by spray drying on hydrophilic surfaces (silica microparticles) on the nanoscale and, in particular, the effect of addition of PEGylated lipids thereon. Scanning electron microscopy showed the presence of nanoparticles of varying sizes on the microparticles with different PEGylated lipid concentrations. Atomic force microscopy confirmed the presence of a lipid coating on the spray-dried microparticles. It also revealed that the lipid-coated microparticles without PEGylated lipids had a rather homogenous coating whereas those with PEGylated lipids had a very heterogeneous coating with defects, which was corroborated by confocal laser scanning microscopy. All coated microparticles had good dispersibility without agglomerate formation, as indicated by particle size measurements. This study has demonstrated that coherent coatings of phospholipids on hydrophilic surfaces can be obtained by spray drying. However, the incorporation of PEGylated lipids in a one-step spray-drying process to prepare lipid coated microparticles with both controlled-release and stealth properties is very challenging.
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| 3. |
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| 4. |
- Dalerum, Fredrik, et al.
(author)
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The influence of distance to perennial surface water on ant communities in Mopane woodlands, northern Botswana
- 2019
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In: Ecology and Evolution. - : Wiley. - 2045-7758. ; 9:1, s. 154-165
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Journal article (peer-reviewed)abstract
- Studies of biodiversity along environmental gradients provide information on how ecological communities change in response to biotic and abiotic factors. For instance, distance to water is associated with several factors that shape the structure and the functioning of ecosystems at a range of spatial scales. We investigated the influence of distance to a perennial water source on ant communities in a semi-arid savanna in northern Botswana. Ant abundance, taxonomic richness, and both alpha and beta diversity were generally higher during the wet than the dry season. However, there were strong seasonal influences on the effects of distance to water, with more pronounced effects during the wet season. While both abundance and beta diversity declined with increasing distances to water during the wet season, there was a contrasting increase in alpha diversity. There was no major effect of distance to water on taxonomic richness during either season. Beta diversity was as high across as along gradients, and we found support for modular rather than nested community structures along gradients. Our study demonstrated that small-scale gradients in distance to water can influence several aspects of ant communities in semi-arid savannas. However, our results also point to strong effects of small-scale environmental variation, for instance associated with vegetation characteristics, soil properties, and plant community structure that are not directly linked to water access.
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| 5. |
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| 6. |
- Garcia-Carreras, Luis, et al.
(author)
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The Impact of Parameterized Convection on the Simulation of Crop Processes
- 2015
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In: Journal of Applied Meteorology and Climatology. - 1558-8424 .- 1558-8432. ; 54:6, s. 1283-1296
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Journal article (peer-reviewed)abstract
- Global climate and weather models are a key tool for the prediction of future crop productivity, but they all rely on parameterizations of atmospheric convection, which often produce significant biases in rainfall characteristics over the tropics. The authors evaluate the impact of these biases by driving the General Large Area Model for annual crops (GLAM) with regional-scale atmospheric simulations of one cropping season over West Africa at different resolutions, with and without a parameterization of convection, and compare these with a GLAM run driven by observations. The parameterization of convection produces too light and frequent rainfall throughout the domain, as compared with the short, localized, high-intensity events in the observations and in the convection-permitting runs. Persistent light rain increases surface evaporation, and much heavier rainfall is required to trigger planting. Planting is therefore delayed in the runs with parameterized convection and occurs at a seasonally cooler time, altering the environmental conditions experienced by the crops. Even at high resolutions, runs driven by parameterized convection underpredict the small-scale variability in yields produced by realistic rainfall patterns. Correcting the distribution of rainfall frequencies and intensities before use in crop models will improve the process-based representation of the crop life cycle, increasing confidence in the predictions of crop yield. The rainfall biases described here are a common feature of parameterizations of convection, and therefore the crop-model errors described are likely to occur when using any global weather or climate model, thus remaining hidden when using climate-model intercomparisons to evaluate uncertainty.
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| 7. |
- Gatto, Francesco, 1987
(author)
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The origin of symmetry in the metabolism of cancer – From systems biology to translational medicine
- 2015
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Doctoral thesis (other academic/artistic)abstract
- Why do not we have a cure for cancer yet? Cancer is the malady of the century, the most intensely studied disease of all time. The question is puzzling. It assumes that cancer is a single entity that we can target and eradicate. On the contrary, the current theory on the origin of cancer dictates that each patient bears a cancer that is an exquisite experiment of nature, in which a unique constellation of genetic aberrations confers the cell with malignant traits that enable it to proliferate and survive until death of the host. Nevertheless, the question is legitimate. Cancer is also a single entity because, in spite of the heterogeneity of origins, every individual cancer in its evolution ought to converge in the acquisition of the same malignant traits, e.g. abnormal proliferation and ability to metastasize. I define this phenomenon of convergent evolution as the symmetry of cancer and each of these traits as symmetric, reminiscent of the fact that as diverse as two individual cancers can be in its origin, they can be repositioned along the trait to be identical.This thesis is dedicated to understanding the origin of symmetry of cancer through systems biology. In particular, I focused my interest in a specific malignant trait, the reprogramming of cell metabolism. Metabolic reprogramming in cancer is associated with deregulation of anabolism and energy metabolism to foster rapid cell proliferation and plastic adaptation to enable cell survival. Human metabolism is a complex system, which consists of thousands of biochemical reactions that transform nutrients into energy, building blocks for cell growth (like membrane phospholipids), macromolecules with specialized functions (like hormones), and in general support life by maintaining whole body homeostasis. I sought to explore whether the transformation to cancer entailed some symmetric patterns of regulation of metabolism. In order to undertake an unbiased view of this complex system, I adopted a systems level perspective, in which genome-scale changes of gene and protein expression (so-called omics) attributable to cancer were bridged with the network of reactions that form the backbone of human metabolism. The results were two-fold. First, any cancer seemed to acquire a symmetric overexpression of nucleotide metabolism, regardless from where it originated (Paper I). However, the comparison was performed against the matched healthy tissues of origin, mostly composed of quiescent cells. Therefore we ascribed this symmetry to an adaptation to a metabolic requirement of cellular proliferation. In order to discern what regulatory patterns in metabolism are not adaptive but oncogenic, meaning an obligate metabolic reprogramming to foster evolution, we characterized those gene expression changes occurring in presence of an oncogenic mutation, again irrespective of the tissue of origin or other confounding factor (Paper II). This analysis revealed that oncogenic mutations independently converge on the deregulation of a sub-network revolving around the metabolism of arachidonic acid and xenobiotics mediated by glutathione and oxygen, which we termed AraX. Deregulation of AraX can be associated with a successful engagement of the immune system in tumor evolution, suggesting that the symmetry of cancer metabolism may exclusively rely on reprogramming fluxes to support pro-tumorigenic inflammation. Second, the symmetry of cancer metabolism broke with the most common form of kidney cancer, clear cell renal cell carcinoma (ccRCC). We reported that a ccRCC-specific set of genetic aberrations is associated with the emergence of a uniquely compromised metabolic network (Paper I). These outstanding features of ccRCC metabolism provided an opportunity for translational medicine. We proved that it is possible to exploit ccRCC defective network to predict computationally metabolic liabilities that induce selective cell death in ccRCC (Paper III). Moreover, these changes in metabolic regulation unique to ccRCC can be distilled, through an algorithm of our creation, Kiwi (Paper V), in a coordinated regulation of glycosaminoglycan biosynthesis (GAGs) (Paper IV). This is mirrored by an altered profile of GAGs in kidney-proximal fluids, urine and blood, that we prove bearing a strong, accurate, and robust diagnostic value in metastatic ccRCC. The case of ccRCC and potential role of inflammation in AraX may raise more doubt than support on the existence of symmetry in the metabolic reprogramming in any cancer cell (Paper VI). Perhaps researchers are simply observing an enhanced plasticity in the adaptation to ever-changing conditions that is induced by mutations, but which is not symmetric under any specific trait and as such not essential to cancer. Yet, I argue that the quest for searching the symmetry in cancer should not be abandoned. This quest is in my opinion of paramount importance to unlock the discovery of a cure for cancer.
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| 8. |
- Hogmark, S, et al.
(author)
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Guest editorial
- 2003
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In: Wear. ; 254, s. 1061-
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Journal article (peer-reviewed)
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| 9. |
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Looking back, looking ahead : land, agriculture and society in East Africa : a festschrift for Kjell Havnevik
- 2015
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Editorial collection (other academic/artistic)abstract
- Is Africa rising? Many countries in sub-Saharan Africa experience remarkable growth. Afro-optimists claim that an economic transformation is imminent, while critics argue that growth is mainly in the extractive sectors, with little improvement being noted among the rural and urban poor.This collection of essays focuses on East Africa, with an emphasis on Tanzania. It is published as Professor Kjell Havnevik retires from the Nordic Africa Institute. He has carried out research, taught and supervised students, and participated in policy debates on agriculture, the environment and development policies in Africa.In this volume, authors review the challenges that agricultural producers have faced in the past and risk facing today and tomorrow; customary and individual land tenure regimes; the character of current growth; and policy dialogue between the donor community and the Tanzanian government. Several contributions converge on the drive for large-scale land acquisitions, their potential and shortcomings, as well as on the policy alternative – investment in small-scale farming. The book also includes essays on religion and education.In addressing all these development issues, these essays are a fitting tribute to the work of Kjell Havnevik, his colleagues and students.
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| 10. |
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| 11. |
- Vinande, E., et al.
(author)
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GPS bistatic radar measurements of aircraft altitude and ground objects with a software receiver
- 2005
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In: Proceedings of the 61st Annual meeting of the Institute of Navigation. - : Institute of Navigation, The. ; , s. 528-534
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Conference paper (peer-reviewed)abstract
- The GPS bistatic radar concept exploits the differences between direct and ground reflected signals received from one or more GPS satellites to aid in navigation or for remote sensing of the surface or transmission medium. This paper provides an overview of an implementation of the technique using a MATLAB-based software receiver and presents example results from an overland flight test. The sample data set was collected during a twenty minute segment of a flight test performed with a NASA Gulfstream V on 20-August-2004. Raw GPS data samples were recorded at 16 MHz from zenith- and nadir-pointing GPS antennas through a custom RF front end and data logger. These samples were post-processed using C/A code software GPS receiver techniques. The bistatic radar measurements are converted to a height above ground level and reflected signal-to-noise ratio. The height measurements are found to follow the trends computed based on receiver solved for height and digital elevations. Signal power is highly correlated with ground type with water returns producing the highest power reflections followed by large man made objects.
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| 12. |
- Bahbou, M. Fouzi, 1973-, et al.
(author)
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Relationship between surface topgraphy parameters and adhesion strength for plasma spraying
- 2005
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In: ITSC 2005. - : The Material Information Society. ; , s. 1027-1031
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Conference paper (peer-reviewed)abstract
- To achieve sufficient adhesion strength within thermal spraying, the surface to be coated has to be modified. Grit blasting is the most common way to generate a clean and roughened surface. The bonding mechanism between the grit-blasted substrate and the coating is assumed to be due to mechanical anchoring, why an optimal surface roughness is essential. The surface roughness is usually evaluated using Ra which cannot fully characterize the complex nature of the chaotic substrate topography. This study was performed in order to evaluate if Ra can be replaced by other surface characteristic parameters such us R.q, Rpk, Rpv, Rk…with higher correlation to adhesion strength. Average roughness was measured by a perthometer and with white light interferometry to get 3D images of the surface topography. Disc shaped substrate samples of Ti6Al4V (AMS 4928) were grit blasted with aluminium oxide grit and plasma sprayed with a Ni5%Al coating. Adhesion strength was determined according to the ASTM C633 standard. The correlation between a number of different surface-parameters and adhesion strength were evaluated and compared with Ra.
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| 13. |
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| 14. |
- Eassa, Fathy Elbouraey, et al.
(author)
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ACC_TEST : Hybrid Testing Approach for OpenACC-Based Programs
- 2020
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In: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 8, s. 80358-80368
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Journal article (peer-reviewed)abstract
- In recent years, OpenACC has been used in many supercomputers and attracted many non-computer science specialists for parallelizing their programs in different scientific fields, including weather forecasting and simulations. OpenACC is a high-level programming model that supports parallelism and is easy to learn to use by adding high-level directives without considering too many low-level details. Testing parallel programs is a difficult task, made even harder if using programming models, especially if they have been badly programmed. If so, it will be challenging to detect their runtime errors as well as their causes, whether the error is from the user source code or from the programming model directives. Even when these errors are detected and the source code modified, we cannot guarantee that the errors have been corrected or are still hidden. There are many tools and studies that have investigated several programming models for identifying and detecting related errors. However, OpenACC has not been targeted clearly in any testing tool or previous studies, even though OpenACC has many benefits and features that could lead to increasing use in achieving parallel systems with less effort. In this paper, we enhance ACC_TEST with the ability to test OpenACC-based programs and detect runtime errors by using hybrid-testing techniques that enhance error coverage occurring in OpenACC as well as overheads and testing time.
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| 15. |
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| 16. |
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| 17. |
- Goodfellow, Bradley W., et al.
(author)
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Last ice sheet recession and landscape emergence above sea level in east-central Sweden, evaluated using in situ cosmogenic 14C from quartz
- 2024
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In: GEOCHRONOLOGY. - 2628-3719. ; 6:2, s. 291-302
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Journal article (peer-reviewed)abstract
- In situ cosmogenic C-14 (in situ C-14) in quartz provides a recently developed tool to date exposure of bedrock surfaces of up to similar to 25 000 years. From outcrops located in east-central Sweden, we tested the accuracy of in situ C-14 dating against (i) a relative sea level (RSL) curve constructed from radiocarbon dating of organic material in isolation basins and (ii) the timing of local deglaciation constructed from a clay varve chronology complemented with traditional radiocarbon dating. Five samples of granitoid bedrock were taken along an elevation transect extending southwestwards from the coast of the Baltic Sea near Forsmark. Because these samples derive from bedrock outcrops positioned below the highest postglacial shoreline, they target the timing of progressive landscape emergence above sea level. In contrast, in situ C-14 concentrations in an additional five samples taken from granitoid outcrops above the highest postglacial shoreline, located 100 km west of Forsmark, should reflect local deglaciation ages. The 10 in situ C-14 measurements provide robust age constraints that, within uncertainties, compare favourably with the RSL curve and the local deglaciation chronology. These data demonstrate the utility of in situ C-14 to accurately date ice sheet deglaciation, and durations of postglacial exposure, in regions where cosmogenic Be-10 and Al-26 routinely return complex exposure results.
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| 18. |
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| 19. |
- Guillemain, Matthieu, et al.
(author)
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Predation risk constrains the plasticity of foraging behaviour in teals, Anas crecca : a flyway-level circumannual approach
- 2007
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In: Animal Behaviour. - : Academic Press Inc.. - 0003-3472 .- 1095-8282. ; 73:5, s. 845-854
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Journal article (peer-reviewed)abstract
- The trade-off foragers make between predation risk and feeding efficiency is readily studied in dabbling ducks, which have stereotyped feeding methods, some of which prevent predator detection while others do not. Teals forage mostly with only the bill submerged (eyes above the water surface) in winter, but use a broader foraging repertoire in summer. Given the different environments used by teals over the year, it is likely that such a shift is due to changes in diet, but it may also be caused by differences in predation risk between habitats. However, neither predation risk nor teal behaviour has been studied with consistent methods around the year or throughout any of its flyways. Covering wintering, spring-staging, breeding and moulting sites, we combined focal observations of teals and predator flyover data from seven regions ranging from southern France to northern Sweden. Although not apparent at the scale of days within sites, teals indeed relied more on shallow foraging where predation risk was higher, i.e. at wintering sites. Average foraging depth increased gradually from September to August, i.e. from wintering to breeding sites. Foraging bout length of deeply foraging teals did not decrease over the year, suggesting that it is through selection of foraging technique, rather than by the balance between foraging and interruptions, that birds adjust to predation risk. This study highlights behavioural plasticity in response to contrasting selection regimes within a flyway, in dabbling ducks as well as long-distance migrants in general.
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| 20. |
- Heshmati, Almas, et al.
(author)
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Policy Simulation of Firms’ Cooperation in Innovation
- 2015
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In: Research Evaluation. - : Oxford University Press (OUP). - 0958-2029 .- 1471-5449. ; 24:3, s. 293-311
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Journal article (peer-reviewed)abstract
- This study utilizes an agent-based simulation model to conduct a public policy simulation of firms' networking and cooperation in innovation. The simulation game tests the differences in sector responses to internal and external changes, including cross-sector spillovers, when applying three different policy strategies to promote cooperation in innovation. The public policy strategies include clustering to develop certain industries, incentives to encourage cooperative research and development (R&D), and spin-off policies to foster entrepreneurship among R&D personnel. These policies are compared to a 'no-policy' alternative, which serves as a benchmark to verify the gains (or loses) in the number of firms cooperating and networking. The simulation model defines firms' behavior according to empirical findings from an analysis of determinants of the firms' participation in cooperation in innovation with other organizations using a Korean Innovation Survey. The exercise indicates possible appropriate policy strategies that can be applied depending on the target industries. We have applied a few examples and showed how the results may be interpreted. Agent-based models are found to have a great potential in decision-support systems for policy makers.
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| 21. |
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| 22. |
- Hylander, Ingrid
(author)
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Handledning och konsultation : jämförelse mellan två professionella psykologiska processer
- 1995
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Reports (other academic/artistic)abstract
- This report adresses the two concepts of Supervision and Consultation.Consultation is defined according to the tradition within Human Service Consultation and particularly to Gerald Caplans`Mental Health Consultation. It is proposed that Gerald Caplans` way of differentiating between 4 types of consultation, can be used in a more general way to include various types of consultationmodels from other traditions. For consultation 5 main criteras are synthezised from different definitons of consultation. For supervision, an overview of different types of supervision is presented. A comparison in regard to the main criterias is made between the two processes most difficult to separate, i.e. psychological (consultee centered case) consultation and "on the job supervision", when the supervisor has no administrative power. Two concepts salient to the supervison process, learning alliance and educational diagnoses are also discussed.It is proposed that analyzing the basic function of the relation between the client and the consultee, in real life, is always prior to defining the indirect helping process e. g. separating the process of supervision from the process of consultation.Finally a third process named "role structuring" is presented, separate from both supervision and psychological consultation. Role structuring is used when the relation between client and consultee is semi professional, or when the professional limits of this relation is only vaguely defined .
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| 23. |
- Koop, Gary, et al.
(author)
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Reconciled Estimates of Monthly GDP in the United States
- 2023
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In: Journal of business & economic statistics. - : Taylor & Francis. - 0735-0015 .- 1537-2707. ; 41:2, s. 563-577
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Journal article (peer-reviewed)abstract
- In the US, income and expenditure-side estimates of GDP (GDPI and GDPE) measure “true” GDP with error and are available at a quarterly frequency. Methods exist for using these proxies to produce reconciled quarterly estimates of true GDP. In this paper, we extend these methods to provide reconciled historical true GDP estimates at a monthly frequency. We do this using a Bayesian mixed frequency vector autoregression (MF-VAR) involving GDPE, GDPI, unobserved true GDP, and monthly indicators of short-term economic activity. Our MF-VAR imposes restrictions that reflect a measurement-error perspective (that is, the two GDP proxies are assumed to equal true GDP plus measurement error). Without further restrictions, our model is unidentified. We consider a range of restrictions that allow for point and set identification of true GDP and show that they lead to informative monthly GDP estimates. We illustrate how these new monthly data contribute to our historical understanding of business cycles and we provide a real-time application nowcasting monthly GDP over the pandemic recession.
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| 24. |
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| 25. |
- Magrini, L., et al.
(author)
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The Gaia-ESO Survey: Insights into the inner-disc evolution from open clusters
- 2015
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In: Astronomy & Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 580
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Journal article (peer-reviewed)abstract
- Context. The inner disc, which links the thin disc with the bulge, has been somewhat neglected in the past because of the intrinsic difficulties in its study, among which crowding and high extinction. Open clusters located in the inner disc are among the best tracers of its chemistry at different ages and distances. Aims. We analyse the chemical patterns of four open clusters located within 7 kpc of the Galactic centre and of field stars to infer the properties of the inner disc with the Gaia-ESO survey idr2/3 data release. Methods. We derive the parameters of the newly observed cluster, Berkeley 81, finding an age of about 1 Gyr and a Galactocentric distance of similar to 5.4 kpc. We construct the chemical patterns of clusters and we compare them with those of field stars in the solar neighbourhood and in the inner-disc samples. Results. Comparing the three populations we observe that inner-disc clusters and field stars are both, on average, enhanced in [O/Fe], [Mg/Fe], and [Si/Fe]. Using the idr2/3 results of M67, we estimate the non-local thermodynamic equilibrium (NLTE) effect on the abundances of Mg and Si in giant stars. After empirically correcting for NLTE effects, we note that NGC 6705 and Be 81 still have a high [alpha/Fe]. Conclusions. The location of the four open clusters and of the field population reveals that the evolution of the metallicity [Fe/H] and of [alpha/Fe] can be explained within the framework of a simple chemical evolution model: both [Fe/H] and [alpha/Fe] of Trumpler 20 and of NGC 4815 are in agreement with expectations from a simple chemical evolution model. On the other hand, NGC 6705, and to a lesser degree Berkeley 81, have higher [alpha/Fe] than expected for their ages, location in the disc, and metallicity. These differences might originate from local enrichment processes as explained in the inhomogeneous evolution framework.
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