881 resultados para 230106 Real and Complex Functions


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This study focuses on the phenomenon of customer reference marketing in a business tobusiness (B to B) context. Although customer references are generally considered an important marketing and sales tool, the academic literature has paid surprisingly little attention to the phenomenon. The study suggests that customer references could be viewed as important marketing assets for industrial suppliers, and the ability to build, manage and leverage customer reference portfolios systematically constitutes a relevant marketing capability. The role of customer references is examined in the context of the industrial suppliers' shift towards a solution and project orientation and in the light of the on going changes in the project business. Suppliers in several industry sectors are undergoing a change from traditional equipment manufacturing towards project and solution oriented business. It is argued in this thesis that the high complexity, the project oriented nature and the intangible service elements that characterise many contemporary B to B offerings further increase the role of customer references. The study proposes three mechanisms of customer reference marketing: status transfer, validation through testimonials and the demonstration of experience and prior performance. The study was conducted in the context of Finnish B to B process technology and information technology companies. The empirical data comprises 38 interviews with managers of four case companies, 165 customer reference descriptions gathered from six case companies' Web sites, as well as company internal material. The findings from the case studies show that customer references have various external and internal functions that contribute to the growth and performance of B to B firms. Externally, customer references bring status transfer effects from reputable customers, concretise and demonstrate complex solutions, and provide indirect evidence of experience, previous performance, technological functionality and delivered customer value. They can also be leveraged internally to facilitate organisational learning and training, advance offering development, and motivate personnel. Major reference projects create new business opportunities and can be used as a vehicle for strategic change. The findings of the study shed light on the on going changing orientations in the project business environment, increase understanding of the variety of ways in which customer references can be deployed as marketing assets, and provide a framework of the relevant tasks and activities related to building, managing and leveraging a firm's customer reference portfolio. The findings contribute to the industrial marketing research, to the literature on marketing assets and capabilities and to the literature on projects and solutions. The proposed functions and mechanisms of customer reference marketing bring a more thorough and structured understanding about the essence and characteristics of the phenomenon and give a wide ranging view of the role of customer references as marketing assets for B to B firms. The study suggests several managerial implications for industrial suppliers in order to systematise customer reference marketing efforts.

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Ru-Sn/Al2O3 catalysts with different Sn loadings were prepared by the coimpregnation method. Several characterization techniques such as TPR, pyridine TPD and catalytic tests for dehydrogenation and hydrogenolysis were used to evaluate and compare such catalysts. TPR results indicate that Sn is deposited both onto the support and as species strongly interacting with Ru. Such non selective deposition modifies the acid and metallic functions of the catalysts. Both total acidity and acid strength distribution are affected: total acidity decreases and new sites of lower acid strength are created. Both dehydrogenating and hydrogenolytic activities are strongly diminished by the addition of Sn. Results of catalytic tests for methyl oleate hydrogenation indicate that methyl stearate is the main product, with only minute amounts of oleyl alcohol produced, and that the addition of Sn diminishes the hydrogenation activity.

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Web application performance testing is an emerging and important field of software engineering. As web applications become more commonplace and complex, the need for performance testing will only increase. This paper discusses common concepts, practices and tools that lie at the heart of web application performance testing. A pragmatic, hands-on approach is assumed where applicable; real-life examples of test tooling, execution and analysis are presented right next to the underpinning theory. At the client-side, web application performance is primarily driven by the amount of data transmitted over the wire. At the server-side, selection of programming language and platform, implementation complexity and configuration are the primary contributors to web application performance. Web application performance testing is an activity that requires delicate coordination between project stakeholders, developers, system administrators and testers in order to produce reliable and useful results. Proper test definition, execution, reporting and repeatable test results are of utmost importance. Open-source performance analysis tools such as Apache JMeter, Firebug and YSlow can be used to realise effective web application performance tests. A sample case study using these tools is presented in this paper. The sample application was found to perform poorly even under the moderate load incurred by the sample tests.

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A simple and sensitive method has been proposed for the determination of sibutramine-HCl in energy drinks, green tea and pharmaceutical formulations using differential pulse voltammetry performed on a hanging mercury drop electrode. In the chosen experimental condition (Mcllvaine pH 4.0 buffer, 50 mV pulse amplitude and 40 mV s-1 scan velocity), sibutramine-HCl presented a reversible behavior and a peak maximum at -80 mV. Detection limit was 0.4 mg L-1 and the working linear range extended up to 33.3 mg L-1 (r = 0.99). Analysis of real and fortified samples enabled recoveries between 91 and 102%. The electroanalytical method was compared with a HPLC method which indicated it accuracy.

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Satelliittipaikannuksen hyödyntäminen eri sovellusaloilla ja siviilikäytössä on kasvanut merkittävästi 2000-luvulla Yhdysvaltojen puolustusministeriön lopetettua GPS-järjestelmän tarkoituksenmukaisen häirinnän. Langattomien datayhteyksien yleistyminen ja nopeuksien kasvaminen on avannut paikkatiedon käyttämiseksi ja hyödyntämiseksi reaaliaikaisesti uusia mahdollisuuksia. Kustannusten kasvaessa on tehokkaasta liikennöinnistä tullut tänä päivänä erittäin tärkeä osa yritysten päivittäisiä toimintoja. Ajoneuvojen hallinta on yksi tapa, jolla pyritään tehostamaan logistisia toimintoja ja vähentämään siitä aiheutuvia kustannuksia. Seuraamalla reaaliaikaisesti ajoneuvojen liikennöintiä voidaan pyrkiä saavuttamaan säästöjä optimoimalla aikatauluja ja reittejä sekä uudelleenohjaamalla ajoneuvoja sijaintien mukaan vähentäen näin kuljettua matkaa ja aikaa. Tässä diplomityössä tavoitteena on tutkia kuinka satelliittipaikannusta, paikkatietoa ja langattomia datayhteyksiä hyödyntämällä voidaan toteuttaa reaaliaikainen jäljitysohjelmisto. Työssä esitellään aluksi paikannustekniikat ja niiden toiminta. Lisäksi tutkitaan kuinka tiedonsiirto voidaan järjestelmässä toteuttaa sekä tarkastellaan järjestelmän kehityksessä huomioitavia tietoturvanäkökohtia. Tutkimuksen pohjalta suunniteltiin ja toteutettiin reaaliaikainen jäljitysohjelmisto kotipalveluyrityksen ajoneuvojen paikannustarpeisiin. Järjestelmän avulla voidaan valvoa ja jäljittää ajoneuvojen sijainteja kartalla reaaliaikaisesti sekä paikantaa tiettyä kohdetta lähimpänä olevat ajoneuvot. Tämä mahdollistaa hälytyksen sattuessa lähimpänä olevan työntekijän lähettämisen asiakaskohteeseen mahdollisimman nopeasti. Järjestelmän avulla käyttäjät voivat lisäksi seurata ajamiaan matkoja ja pitää automaattista ajopäiväkirjaa. Lopuksi työssä arvioidaan toteutetun järjestelmän toimintaa testauksessa saatujen mittaustulosten perusteella.

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Electrode kinetics and complex formation of Zn(II) using doxycycline, chlortetracycline, oxytetracycline, tetracycline, minocycline, amoxicillin, chloramphenicol and cephaloglycin were reported at pH = 7.30 ± 0.01 in = 1.0 molL-1 NaClO4 used as supporting electrolyte at 25.0°C. Kinetic parameters viz. transfer coefficient (α), degree of irreversibility (λ) and rate constant (k) were determined. The study showed that 'Transition state' behaves between reactant (O) and product (R) response to applied potential. The stability constants varied from 2.14 to 10.31 showing that these drugs or their complexes could be used against Zn toxicity.

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By alloying metals with other materials, one can modify the metal’s characteristics or compose an alloy which has certain desired characteristics that no pure metal has. The field is vast and complex, and phenomena that govern the behaviour of alloys are numerous. Theories cannot penetrate such complexity, and the scope of experiments is also limited. This is why the relatively new field of ab initio computational methods has much to give to this field. With these methods, one can extend the understanding given by theories, predict how some systems might behave, and be able to obtain information that is not there to see in physical experiments. This thesis pursues to contribute to the collective knowledge of this field in the light of two cases. The first part examines the oxidation of Ag/Cu, namely, the adsorption dynamics and oxygen induced segregation of the surface. Our results demonstrate that the presence of Ag on the Cu(100) surface layer strongly inhibits dissociative adsorption. Our results also confirmed that surface reconstruction does happen, as experiments predicted. Our studies indicate that 0.25 ML of oxygen is enough for Ag to diffuse towards the bulk, under the copper oxide layer. The other part elucidates the complex interplay of various energy and entropy contributions to the phase stability of paramagnetic duplex steel alloys. We were able to produce a phase stability map from first principles, and it agrees with experiments rather well. Our results also show that entropy contributions play a very important role on defining the phase stability. This is, to the author’s knowledge, the first ab initio study upon this subject.

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Sea buckthorn (Hippophaë) berries are ingredients of the Chinese traditional medicine. In addition to China, they are nowadays cultivated for food in several European countries, Russia, Canada, the USA, and Japan. Sea buckthorn berries are a rich source of flavonoids, mainly flavonol glycosides and proanthocyanidins. Depending on the genetic background, growth conditions, and ripeness of the berries, vitamin C concentrations up to over 1 g/100 ml juice, have been reported. Sea buckthorn berries contain inositols and methyl inositols, components of messenger molecules in humans. Sea buckthorn seed oil is rich in essential aplha-linolenic and linoleic acids, whereas the most abundant fatty acids in the berry oil are palmitoleic, palmitic and oleic acids. Other potentially beneficial lipophilic compounds of sea buckthorn seeds and berries include carotenoids, phytosterols, tocopherols and tocotrienols. The effects of sea buckthorn fractions on inflammation, platelet aggregation, oxidation injuries, the liver, skin and mucosa, among others, have been reported. The aim of the thesis work was to investigate the health effects of sea buckthorn berries and oil in humans. The physiological effects of sea buckthorn berries, berry components, and oil have mostly been studied in vitro and in animal models, leaving a demand for more clinical trials. In the first randomized, placebo-controlled trial of this thesis healthy adults consumed 28 g/day of sea buckthorn berries for three months. The main objective was to investigate the effects on the common cold. In addition, effects on other infections, inflammation and circulating lipid markers associated with cardiovascular disease risk were studied. In the second randomized, placebocontrolled trial participants reporting dry eye symptoms consumed 2 g/day of sea buckthorn oil from the seeds and berries for three months. The effects on symptoms and clinical signs of dry eye were monitored. In addition, the effects on circulating markers of inflammation and liver functions were analyzed. Sea buckthorn berries did not affect the common cold or other infections in healthy adults. However, a decrease in serum C-reactive protein was detected, indicating effects on inflammation. Fasting concentrations of serum flavonols, typical to sea buckthorn berry, increased without affecting the circulating total, HDL, LDL cholesterol, or triacylglycerol concentrations. Tear film hyperosmolarity and activation of inflammation at the ocular surface are among the core mechanisms of dry eye. Combined sea buckthorn berry and seed oil attenuated the rise in tear film osmolarity taking place during the cold season. It also positively affected some of the dry eye symptoms. Based on the tear film fatty acid analysis, the effects were not mediated through direct incorporation of sea buckthorn oil fatty acids to tear film lipids. It is likely that the fatty acids, carotenoids, tocopherols and tocotrienols of sea buckthorn oil affected the inflammation of the ocular surface, lacrimal and/or meibomian glands. The effects on the differentiation of meibomian gland cells are also possible. Sea buckthorn oil did not affect the serum concentrations of inflammation markers or liver enzymes investigated. In conclusion, this thesis work suggests positive effects of sea buckthorn berries and oil on inflammation and dry eye, respectively, in humans.

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Female sexual dysfunctions, including desire, arousal, orgasm and pain problems, have been shown to be highly prevalent among women around the world. The etiology of these dysfunctions is unclear but associations with health, age, psychological problems, and relationship factors have been identified. Genetic effects explain individual variation in orgasm function to some extent but until now quantitative behavior genetic analyses have not been applied to other sexual functions. In addition, behavior genetics can be applied to exploring the cause of any observed comorbidity between the dysfunctions. Discovering more about the etiology of the dysfunctions may further improve the classification systems which are currently under intense debate. The aims of the present thesis were to evaluate the psychometric properties of a Finnish-language version of a commonly used questionnaire for measuring female sexual function, the Female Sexual Function Index (FSFI), in order to investigate prevalence, comorbidity, and classification, and to explore the balance of genetic and environmental factors in the etiology as well as the associations of a number of biopsychosocial factors with female sexual functions. Female sexual functions were studied through survey methods in a population based sample of Finnish twins and their female siblings. There were two waves of data collection. The first data collection targeted 5,000 female twins aged 33–43 years and the second 7,680 female twins aged 18–33 and their over 18–year-old female siblings (n = 3,983). There was no overlap between the data collections. The combined overall response rate for both data collections was 53% (n = 8,868), with a better response rate in the second (57%) compared to the first (45%). In order to measure female sexual function, the FSFI was used. It includes 19 items which measure female sexual function during the previous four weeks in six subdomains; desire, subjective arousal, lubrication, orgasm, sexual satisfaction, and pain. In line with earlier research in clinical populations, a six factor solution of the Finnish-language version of the FSFI received supported. The internal consistencies of the scales were good to excellent. Some questions about how to avoid overestimating the prevalence of extreme dysfunctions due to women being allocated the score of zero if they had had no sexual activity during the preceding four weeks were raised. The prevalence of female sexual dysfunctions per se ranged from 11% for lubrication dysfunction to 55% for desire dysfunction. The prevalence rates for sexual dysfunction with concomitant sexual distress, in other words, sexual disorders were notably lower ranging from 7% for lubrication disorder to 23% for desire disorder. The comorbidity between the dysfunctions was substantial most notably between arousal and lubrication dysfunction even if these two dysfunctions showed distinct patterns of associations with the other dysfunctions. Genetic influences on individual variation in the six subdomains of FSFI were modest but significant ranging from 3–11% for additive genetic effects and 5–18% for nonadditive genetic effects. The rest of the variation in sexual functions was explained by nonshared environmental influences. A correlated factor model, including additive and nonadditive genetic effects and nonshared environmental effects had the best fit. All in all, every correlation between the genetic factors was significant except between lubrication and pain. All correlations between the nonshared environment factors were significant showing that there is a substantial overlap in genetic and nonshared environmental influences between the dysfunctions. In general, psychological problems, poor satisfaction with the relationship, sexual distress, and poor partner compatibility were associated with more sexual dysfunctions. Age was confounded with relationship length but had over and above relationship length a negative effect on desire and sexual satisfaction and a positive effect on orgasm and pain functions. Alcohol consumption in general was associated with better desire, arousal, lubrication, and orgasm function. Women pregnant with their first child had fewer pain problems than nulliparous nonpregnant women. Multiparous pregnant women had more orgasm problems compared to multiparous nonpregnant women. Having children was associated with less orgasm and pain problems. The conclusions were that desire, subjective arousal, lubrication, orgasm, sexual satisfaction, and pain are separate entities that have distinct associations with a number of different biopsychosocial factors. However, there is also considerable comorbidity between the dysfunctions which are explained by overlap in additive genetic, nonadditive genetic and nonshared environmental influences. Sexual dysfunctions are highly prevalent and are not always associated with sexual distress and this relationship might be moderated by a good relationship and compatibility with partner. Regarding classification, the results supports separate diagnoses for subjective arousal and genital arousal as well as the inclusion of pain under sexual dysfunctions.

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The objective of this Bachelor's Thesis is to find out the role of social media in the B-to-B marketing environment of the information technology industry and to discover how IT-firms utilize social media as a part of their customer reference marketing. To reach the objectives the concepts of customer reference marketing and social media are determined. Customer reference marketing can be characterized as one of the most practically relevant but academically relatively overlooked ways in which a company can leverage its customers and delivered solutions and use them as references in its marketing activities. We will cover which external and internal functions customer references have, that contribute to the growth and performance of B-to-B firms. We also address the three mechanisms of customer reference marketing which are 'status transfer', 'validation through testimonials' and 'demonstration of experience and prior performance'. The concept of social media stands for social interaction and creation of user-based content which exclusively occurs through Internet. The social media are excellent tools for networking because of the fast and easy access, easy interaction and vast amount of multimedia attributes. The allocation of social media is determined. The case company helps clarify the specific characteristics of social media usage as part of customer-reference-marketing activities. For IT-firms the best channels to utilize social media in their customer reference marketing activities are publishing and distribution services of content and networking services.

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Alzheimer`s disease (AD) is characterised neuropathologically by the presence of extracellular amyloid plaques, intraneuronal neurofibrillary tangles, and cerebral neuronal loss. The pathological changes in AD are believed to start even decades before clinical symptoms are detectable. AD gradually affects episodic memory, cognition, behaviour and the ability to perform everyday activities. Mild cognitive impairment (MCI) represents a transitional state between normal aging and dementia disorders, especially AD. The predictive accuracy of the current and commonly used MCI criteria devide this disorder into amnestic (aMCI) and non-amnestic (naMCI) MCI. It seems that many individuals with aMCI tend to convert to AD. However many MCI individuals will remain stable and some may even recover. At present, the principal drugs for the treatment of AD provide only symptomatic and palliative benefits. Safe and effective mechanism-based therapies are needed for this devastating neurodegenerative disease of later life. In conjunction with the development of new therapeutic drugs, tools for early detection of AD would be important. In future one of the challenges will be to detect at an early stage these MCI individuals who will convert to AD. Methods which can predict which MCI subjects will convert to AD will be much more important if the new drug candidates prove to have disease-arresting or even disease–slowing effects. These types of drugs are likely to have the best efficacy if administered in the early or even in the presymptomatic phase of the disease when the synaptic and neuronal loss has not become too widespread. There is no clinical method to determine with certainly which MCI individuals will progress to AD. However there are several methods which have been suggested as predictors of conversion to AD, e.g. increased [11C] PIB uptake, hippocampal atrophy in MRI, low CSF A beta 42 level, high CSF tau-protein level, apolipoprotein E (APOE) ε4 allele and impairment in episodic memory and executive functions. In the present study subjects with MCI appear to have significantly higher [11C] PIB uptake vs healthy elderly in several brain areas including frontal cortex, the posterior cingulate, the parietal and lateral temporal cortices, putamen and caudate. Also results from this PET study indicate that over time, MCI subjects who display increased [11C] PIB uptake appear to be significantly more likely to convert to AD than MCI subjects with negative [11C] PIB retention. Also hippocampal atrophy seems to increase in MCI individuals clearly during the conversion to AD. In this study [11C] PIB uptake increases early and changes relatively little during the AD process whereas there is progressive hippocampal atrophy during the disease. In addition to increased [11C] PIB retention and hippocampal atrophy, the status of APOE ε4 allele might contribute to the conversion from MCI to AD.

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This work evaluated eight hypsometric models to represent tree height-diameter relationship, using data obtained from the scaling of 118 trees and 25 inventory plots. Residue graphic analysis and percent deviation mean criteria, qui-square test precision, residual standard error between real and estimated heights and the graybill f test were adopted. The identity of the hypsometric models was also verified by applying the F(Ho) test on the plot data grouped to the scaling data. It was concluded that better accuracy can be obtained by using the model prodan, with h and d1,3 data measured in 10 trees by plots grouped into these scaling data measurements of even-aged forest stands.

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Tällä tutkimuksella annetaan työkaluja pienille mikrotason asennusyrityksille heidän tiellään tuottavampaan ja tehokkaampaan yritystoimintaan. Kehitysmenetelmäksi on valittu verkostoituminen, joka tapahtuu alueellisten toimijoiden kesken ja on lähinnä horisontaalista. Tutkimuksen kohderyhmänä on sähkö-, tele- ja antenniasennusyrittäjät tai alalle aikovat uudet yrittäjät. Luotu malli on sovelias lähes kaikille kiinteistöjen teknisen kunnossapidon alalla toimiville mikroyrityksille. Tutkimuksen teoreettisessa osassa käsitellään verkostoyrittäjyyden perusteita ja syventävästi esitetyn case-mallin mukaista verkostotoiminnan erityispiirteitä. Empiirinen osa koostuu sähköisesti toteutetusta internetpohjaisesta kysely- tutkimuksesta, jonka kohteena on pienet sähkö-, tele- ja antenniasennusyritykset. Kyselytutkimus on toteutettu yhteistyössä alan urakointiliittojen (STUL ry ja SANT ry) kanssa. Kysely noudattaa samoja aihealueita kuin professori Asko Miettisen sähköurakointialalle 1988 toteuttaman raportin SÄHKÖURAKOINTI 2000 kyselylomake pidemmän tarkastelujänteen saamiseksi. Kysely selvittää yritysten nykytilaa ja näkemyksiä alan lähitulevaisuudesta. Empiiristä osaa tuetaan voimakkaasti case- esityksin, jotka pohjautuvat kirjoittajan 40 vuoden yrittäjäkokemukseen tällä alalla, joka on ollut voimakkaastikin lähinnä vertikaalisesti verkottunut. Tutkimus osoittaa, että alan taloudellinen ja toiminnallinenkin kehitys on polkenut paikallaan viimeiset vuosikymmenet, vaikka alan teknologiakehitys on ollut tarkasteluajanjaksona varsin merkittävää. Alan yritysten heikohkojen resurssien vuoks entistä voimakkaampi alueellinen yhteistyö verkostoitumalla on mahdollisuus tuottavampaan yritystoimintaan ja arvontuottoon yritykselle sekä luo mahdollisuuden myös suuntautumisen uusille kehittyneimmille teknologian alueille.

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The objective of this thesis was to study the role of capabilities in purchasing and supply management. For the pre-understanding of the research topic, purchasing and supply management development and the multidimensional, unstructured and complex nature of purchasing and supply management performance was studied in literature review. In addition, a capability-based purchasing and supply management performance framework were researched and structured for the empirical research. Due to the unstructured nature of the research topic, the empirical research is three-pronged in this study including three different research methods: the Delphi method, semi-structured interview, and case research. As a result, the purchasing and supply management capability assessment tool was structured to measure current level of capabilities and impact of capabilities on purchasing and supply management performance. The final results indicate that capabilities are enablers of purchasing and supply management performance, and therefore critical to purchasing and supply performance.

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The focus of the present work was on 10- to 12-year-old elementary school students’ conceptual learning outcomes in science in two specific inquiry-learning environments, laboratory and simulation. The main aim was to examine if it would be more beneficial to combine than contrast simulation and laboratory activities in science teaching. It was argued that the status quo where laboratories and simulations are seen as alternative or competing methods in science teaching is hardly an optimal solution to promote students’ learning and understanding in various science domains. It was hypothesized that it would make more sense and be more productive to combine laboratories and simulations. Several explanations and examples were provided to back up the hypothesis. In order to test whether learning with the combination of laboratory and simulation activities can result in better conceptual understanding in science than learning with laboratory or simulation activities alone, two experiments were conducted in the domain of electricity. In these experiments students constructed and studied electrical circuits in three different learning environments: laboratory (real circuits), simulation (virtual circuits), and simulation-laboratory combination (real and virtual circuits were used simultaneously). In order to measure and compare how these environments affected students’ conceptual understanding of circuits, a subject knowledge assessment questionnaire was administered before and after the experimentation. The results of the experiments were presented in four empirical studies. Three of the studies focused on learning outcomes between the conditions and one on learning processes. Study I analyzed learning outcomes from experiment I. The aim of the study was to investigate if it would be more beneficial to combine simulation and laboratory activities than to use them separately in teaching the concepts of simple electricity. Matched-trios were created based on the pre-test results of 66 elementary school students and divided randomly into a laboratory (real circuits), simulation (virtual circuits) and simulation-laboratory combination (real and virtual circuits simultaneously) conditions. In each condition students had 90 minutes to construct and study various circuits. The results showed that studying electrical circuits in the simulation–laboratory combination environment improved students’ conceptual understanding more than studying circuits in simulation and laboratory environments alone. Although there were no statistical differences between simulation and laboratory environments, the learning effect was more pronounced in the simulation condition where the students made clear progress during the intervention, whereas in the laboratory condition students’ conceptual understanding remained at an elementary level after the intervention. Study II analyzed learning outcomes from experiment II. The aim of the study was to investigate if and how learning outcomes in simulation and simulation-laboratory combination environments are mediated by implicit (only procedural guidance) and explicit (more structure and guidance for the discovery process) instruction in the context of simple DC circuits. Matched-quartets were created based on the pre-test results of 50 elementary school students and divided randomly into a simulation implicit (SI), simulation explicit (SE), combination implicit (CI) and combination explicit (CE) conditions. The results showed that when the students were working with the simulation alone, they were able to gain significantly greater amount of subject knowledge when they received metacognitive support (explicit instruction; SE) for the discovery process than when they received only procedural guidance (implicit instruction: SI). However, this additional scaffolding was not enough to reach the level of the students in the combination environment (CI and CE). A surprising finding in Study II was that instructional support had a different effect in the combination environment than in the simulation environment. In the combination environment explicit instruction (CE) did not seem to elicit much additional gain for students’ understanding of electric circuits compared to implicit instruction (CI). Instead, explicit instruction slowed down the inquiry process substantially in the combination environment. Study III analyzed from video data learning processes of those 50 students that participated in experiment II (cf. Study II above). The focus was on three specific learning processes: cognitive conflicts, self-explanations, and analogical encodings. The aim of the study was to find out possible explanations for the success of the combination condition in Experiments I and II. The video data provided clear evidence about the benefits of studying with the real and virtual circuits simultaneously (the combination conditions). Mostly the representations complemented each other, that is, one representation helped students to interpret and understand the outcomes they received from the other representation. However, there were also instances in which analogical encoding took place, that is, situations in which the slightly discrepant results between the representations ‘forced’ students to focus on those features that could be generalised across the two representations. No statistical differences were found in the amount of experienced cognitive conflicts and self-explanations between simulation and combination conditions, though in self-explanations there was a nascent trend in favour of the combination. There was also a clear tendency suggesting that explicit guidance increased the amount of self-explanations. Overall, the amount of cognitive conflicts and self-explanations was very low. The aim of the Study IV was twofold: the main aim was to provide an aggregated overview of the learning outcomes of experiments I and II; the secondary aim was to explore the relationship between the learning environments and students’ prior domain knowledge (low and high) in the experiments. Aggregated results of experiments I & II showed that on average, 91% of the students in the combination environment scored above the average of the laboratory environment, and 76% of them scored also above the average of the simulation environment. Seventy percent of the students in the simulation environment scored above the average of the laboratory environment. The results further showed that overall students seemed to benefit from combining simulations and laboratories regardless of their level of prior knowledge, that is, students with either low or high prior knowledge who studied circuits in the combination environment outperformed their counterparts who studied in the laboratory or simulation environment alone. The effect seemed to be slightly bigger among the students with low prior knowledge. However, more detailed inspection of the results showed that there were considerable differences between the experiments regarding how students with low and high prior knowledge benefitted from the combination: in Experiment I, especially students with low prior knowledge benefitted from the combination as compared to those students that used only the simulation, whereas in Experiment II, only students with high prior knowledge seemed to benefit from the combination relative to the simulation group. Regarding the differences between simulation and laboratory groups, the benefits of using a simulation seemed to be slightly higher among students with high prior knowledge. The results of the four empirical studies support the hypothesis concerning the benefits of using simulation along with laboratory activities to promote students’ conceptual understanding of electricity. It can be concluded that when teaching students about electricity, the students can gain better understanding when they have an opportunity to use the simulation and the real circuits in parallel than if they have only the real circuits or only a computer simulation available, even when the use of the simulation is supported with the explicit instruction. The outcomes of the empirical studies can be considered as the first unambiguous evidence on the (additional) benefits of combining laboratory and simulation activities in science education as compared to learning with laboratories and simulations alone.