”Du sköna sång, vårt bästa arv” - kanonisering av en sångskatt ur ett hermeneutiskt perspektiv

Songs have the power to get through to people. When lyrics are combined with a tune, the result is an entity where the first few notes of a melody can evoke emotions of recognition and belonging. A song treasury consists of such songs that are part of a canonized song tradition. The process where certain songs become part of an established song treasury is long, and many other aspects than the tune itself influence the forming of a song treasury. By examining the characteristics of a song tradition, the history of an ethnic group can be illuminated. In this study, music, pedagogy, and the sociocultural context are merged into a whole where a common song tradition, the song treasury, is in focus. The main aim of this study is to deepen the understanding of a song treasury, its development and contents. This understanding is accomplished by analyzing the musical and lyrical characteristics of 60 songs, which have been sung in schools, homes, and communities, thereby becoming popular among the Swedish-speaking Finns during the 20th century. The songs have been chosen by combining three song lists, of which two lists are closely related to school curricula. The third song list is a result of a survey on favourite songs, according to the situation around year 2000. The songs are examined in their notated versions, a number of song books and text books (n = 29) forming the empirical material. In this study, a hermeneutical approach is applied, content analysis being the method. The analysis is based on three perspectives: the sociocultural perspective, the music-pedagogical perspective, and the musico-analytical perspective. Within each perspective, two aspects are studied. This results in a hexagonal model which forms the structure of the study as a whole. The first two perspectives form the background; a historical context where nation, education, home country, and homestead are regarded as highly important. A common song repertoire is considered to be an effective means of building collective identity within ethnic groups, the common language and the cultural heritage being used as rhetorical arguments. During the early 1900s, choir festivals become an educational platform where conceptions of a common belonging are developed and strengthened through religious, patriotic, and poetical expressions. National school curricula in singing and music have similar characteristics, cultural heritage and values education being in focus. The song lyrics often describe nature and emotions, and they also appear to be personal and situated in a given time and place. Patriotic expressions and songs about music are also fairly common. The songs generally express positive attitudes, which are intensified by major tonality, rich and varied melodies with stable rhythms, and a strong tonal base. The analyzed details of the studied aspects are merged into a thick description, which results in an interpretation pattern with three dimensions: a song treasury can be considered an expression of collective identity, cultural heritage, and values education.

Entrepreneurial orientation in small and medium-sized enterprises during economic crisis

The economic importance of small and medium-sized enterprises (SMEs) and entrepreneurship has increased significantly in recent decades and entrepreneurial activity and SMEs are deemed vital to economic progress. Therefore, it is justifiable to study how small firms and entrepreneurs can enhance their performance and emergence in the turbulent economic environment. The concept of entrepreneurial orientation (EO) has recently attracted considerable attention in the field of entrepreneurship research. EO generally refers to a firm’s propensity to be innovative, to be proactive and to take risks. A majority of EO studies so far have found that adopting EO associated entrepreneurial behaviors will help firms to create or sustain a high level of performance. This dissertation explores the main drivers and performance implications of EO for SMEs in time of economic crisis. Hence the first objective of this dissertation is to examine the performance implications of EO and to test the role of EO on how firms are treated by the crisis at operative level. The second objective is to expand the prevailing understanding of determinants of EO by exploring the relationship between owner's work related values, attitudes, demographic characteristics, firm’s financial resources and EO. EO was found to be a significant and positive factor behind a firm’s long run growth. Hence it can be said that EO has positive implications for firm performance. But on the other hand, during a time of economic crisis the different dimensions of EO had both positive and negative effects on performance of SMEs. The performance implications varied across different stages of the crisis and were also dependent on what measure was used for measuring the performance. The main drivers of EO in SMEs were the personal work related values of the entrepreneur and his/her prior experience as an entrepreneur. The intrinsic work values related to interest, responsibility, challenge, self-development or intellectual stimulation and values related to status, power, achievement and recognition had a positive effect on the level of EO. On the other hand, extrinsic values related to high income, material possessions, benefits such as generous holidays, job security, and comfort through good working conditions decreased the level of EO

Comparison between dSPACE and NI systems based on real-time intelligent control of a teleoperated hydraulic servo system

The Laboratory of Intelligent Machine researches and develops energy-efficient power transmissions and automation for mobile construction machines and industrial processes. The laboratory's particular areas of expertise include mechatronic machine design using virtual technologies and simulators and demanding industrial robotics. The laboratory has collaborated extensively with industrial actors and it has participated in significant international research projects, particularly in the field of robotics. For years, dSPACE tools were the lonely hardware which was used in the lab to develop different control algorithms in real-time. dSPACE's hardware systems are in widespread use in the automotive industry and are also employed in drives, aerospace, and industrial automation. But new competitors are developing new sophisticated systems and their features convinced the laboratory to test new products. One of these competitors is National Instrument (NI). In order to get to know the specifications and capabilities of NI tools, an agreement was made to test a NI evolutionary system. This system is used to control a 1-D hydraulic slider. The objective of this research project is to develop a control scheme for the teleoperation of a hydraulically driven manipulator, and to implement a control algorithm between human and machine interaction, and machine and task environment interaction both on NI and dSPACE systems simultaneously and to compare the results.

Bio-ethanol valorization towards C4s including 1-butanol over metal modified alumina and zeolite catalysts

Bio-ethanol has been used as a fuel additive in modern society aimed at reducing CO2-emissions and dependence on oil. However, ethanol is unsuitable as fuel supplement in higher proportions due to its physico-chemical properties. One option to counteract the negative effects is to upgrade ethanol in a continuous fixed bed reactor to more valuable C4 products such as 1-butanol providing chemical similarity with traditional gasoline components. Bio-ethanol based valorization products also have other end-uses than just fuel additives. E.g. 1-butanol and ethyl acetate are well characterised industrial solvents and platform chemicals providing greener alternatives. The modern approach is to apply heterogeneous catalysts in the investigated reactions. The research was concentrated on aluminium oxide (Al2O3) and zeolites that were used as catalysts and catalyst supports. The metals supported (Cu, Ni, Co) gave very different product profiles and, thus, a profound view of different catalyst preparation methods and characterisation techniques was necessary. Additionally, acidity and basicity of the catalyst surface have an important role in determining the product profile. It was observed that ordinary determination of acid strength was not enough to explain all the phenomena e.g. the reaction mechanism. One of the main findings of the thesis is based on the catalytically active site which originates from crystallite structure. As a consequence, the overall evaluation of different by-products and intermediates was carried out by combining the information. Further kinetic analysis was carried out on metal (Cu, Ni, Co) supported self-prepared alumina catalysts. The thesis gives information for further catalyst developments aimed to scale-up towards industrially feasible operations.

The Relationship of Organizational Culture, Employee Motivation and Innovativeness: Evidence from Finnish Technology Industries

The purpose of this thesis is to analyze the effects of tangible and intangible incentives on the dimensions of motivation and organizational innovativeness in the context of different organizational cultures. Theory suggests that an antecedent of innovativeness is individual creativity of employees, which is influenced by intrinsic motivation, flexible organizational structures, and transformational leadership. Empirical evidence for this research is derived from 424 respondents representing technology-driven industries in Finland. Data is collected through an online questionnaire and analyzed using SPSS statistics software. The results imply that intangible incentives and intrinsic motivation have an important role in determining organizational innovativeness. The positive relationships of intangible incentives, intrinsic motivation and innovativeness seem to be higher in flexible organizational cultures. As practical implications, managers should foster flexible organizational cultures that highlight employee empowerment. The motivating power of non-financial intrinsic incentives and recognition of good work should not be undermined when compared to tangible monetary rewards.

Developing of Supportive Context for Eco-Industrial Networks in Finland

The aim of the present thesis was to explore possible promotional actions to support the emergence of eco-industrial business networks in Finland. The main objectives were to investigate what kind of factors affect in the development of eco-industrial networks and further make suggestions in what kinds of actions this could be supported. In addition, since the active facilitation was discovered as one potential promoting activity, further investigation about facilitation process in Finnish context was conducted and also main characteristics of nationwide facilitation programme were identified. This thesis contains literature review of network orchestration and eco-industrial networks. The latter consists of green supply chain management and industrial symbiosis, although the main focus of the study leans on the concept of industrial symbiosis. The empirical data of the study was obtained from semi-structured expert interviews. These interviews were analyzed using qualitative content analysis. The study identified four main promotional activities for eco-industrial networks: 1) building awareness, 2) incentives, 3) dismantling of legislative barriers and 4) active facilitation. In addition, a framework for facilitation activities in Finnish context was built and main characteristics of nationwide facilitation programme were identified.

Leaf contents of nitrogen and phenolic compounds and their bearing with the herbivore damage to Tibouchina pulchra Cogn. (Melastomataceae), under the influence of air pollutants from industries of Cubatão, São Paulo

The Atlantic Forest on the slopes of Serra do Mar around Cubatão (São Paulo, Brazil) has been affected by massive emissions of pollutants from the local growing industrial complex. The effects of air pollution on the amounts of leaf nitrogen, total soluble phenols and total tannins of Tibouchina pulchra Cogn., a common species in the area of Cubatão, were investigated, as well as the possible influence of the altered parameters on the leaf area damaged by herbivores. Fully expanded leaves were collected at two sites: the valley of Pilões river (VP), characterized by a vegetation virtually not affected by air pollution and taken as a reference; and valley of Mogi river (VM), close to the core region of the industrial complex, and severely affected by air pollution. No differences were observed for any parameters between samples collected in the summer and winter in both sites. On the other hand, compared to VP, individuals growing in VM presented higher amounts of nitrogen and lower amounts of total soluble phenols and total tannins, as well as higher percentages of galls per leaf and higher leaf area lost to herbivores. Regression analysis revealed that the increase in leaf area lost to herbivores can be explained by the increase of the content of nitrogen and decrease in the contents of total soluble phenols and total tannins. Although significant, the coefficients of explanation found were low for all analyses, suggesting that other biotic or abiotic factors are likely to influence leaf attack by herbivores.

Railways, Airports and Sea Container Operators as Publicly Listed Companies – Financial Performance and Shareholder Value Creation Perspective

Logistics infrastructure and transportation services have been the liability of countries and governments for decades, or these have been under strict regulation policies. One of the first branches opened for competition in EU as well as in other continents, has been air transports (operators, like passenger and freight) and road transports. These have resulted on lower costs, better connectivity and in most of the cases higher service quality. However, quite large amount of other logistics related activities are still directly (or indirectly) under governmental influence, e.g. railway infrastructure, road infrastructure, railway operations, airports, and sea ports. Due to the globalization, governmental influence is not that necessary in this sector, since transportation needs have increased with much more significant phase as compared to economic growth. Also freight transportation needs do not correlate with passenger side, due to the reason that only small number of areas in the world have specialized in the production of particular goods. Therefore, in number of cases public-private partnership, or even privately owned companies operating in these sub-branches have been identified as beneficial for countries, customers and further economic growth. The objective of this research work is to shed more light on these kinds of experiments, especially in the relatively unknown sub-branches of logistics like railways, airports and sea container transports. In this research work we have selected companies having public listed status in some stock exchange, and have needed amount of financial scale to be considered as serious company rather than start-up phase venture. Our research results show that railways and airports usually need high fixed investments, but have showed in the last five years generally good financial performance, both in terms of profitability and cash flow. In contrary to common belief of prosperity in globally growing container transports, sea vessel operators of containers have not shown that impressive financial performance. Generally margins in this business are thin, and profitability has been sacrificed in front of high growth – this also concerns cash flow performance, which has been lower too. However, as we examine these three logistics sub-branches through shareholder value development angle during time period of 2002-2007, we were surprised to find out that all of these three have outperformed general stock market indexes in this period. More surprising is the result that financially a bit less performing sea container transportation sector shows highest shareholder value gain in the examination period. Thus, it should be remembered that provided analysis shows only limited picture, since e.g. dividends were not taken into consideration in this research work. Therefore, e.g. US railway operators have disadvantage to other in the analysis, since they have been able to provide dividends for shareholders in long period of time. Based on this research work we argue that investment on transportation/logistics sector seems to be safe alternative, which yields with relatively low risk high gain. Although global economy would face smaller growth period, this sector seems to provide opportunities in more demanding situation as well.

Heritage through Fiction: Dracula Tourism in Romania

Heritage and tourism have become inextricably linked. This link can be seen as producing inauthentic and falsified tradition, and it can therefore be seen as a threat to cultural heritage. On the other hand the link can be seen as a positive thing, as something which helps to preserve herit-age, culture and folklore in a changing and globalising world. This dissertation investigates heritage in the context of Dracula Tourism in Romania. Dracula tourism is tourism where tourists visit places connected with either the fictional vampire Dracula or the historical Dracula, a Romanian historical ruler Vlad the Impaler. The main research question of this study is how can Romanian heritage and culture be shown and promoted through a seemingly superficial Dracula tourism which is based on Western popular cul-ture? And is it possible to find Romanian heritage through popular fiction in Dracula tourism? The main sources for this work are based on the fieldwork done by the author in 2010 and 2011 and the web pages of ten Romanian travel agencies that offer Dracula tourism. The stories and images found on the web pages and used by the tour guides form the bulk of the research material. The emphasis and perspective of this research is folkloristic. Critical discourse analysis and multimodal discourse analysis form the main theoretical approach of this dissertation. In addition the research material is approached through intertextuality, folklore process, hybridisation, authenticity and social constructionism. This dissertation aims to offer new perspectives on the research literature concerning tourism and heritage and to offer a folkloristic view of tourism research. It also aims to offer new perspectives to folkloristics in terms of the research on the use of folklore and tradition and offer new perspectives on the use and definition of the concept of authenticity. Although the research subject of this thesis is Dracula tourism in Romania, the findings can be utilised and applied in a larger context and field of research. The key research findings show that heritage can be found within Dracula Tourism in three forms: as defined from above (UNESCO World Heritage Sites), as local heritage and as a form of opposition. The Romanian travel agencies researched in this dissertation use Dracula tourism as a gateway into Romanian history, culture, tradition and heritage. Kulttuuriperintö ja turismi yhdistyvät toisiinsa erottamattomasti. Toisaalta tämän yhteyden on nähty tuottavan epäautenttista ja väärennettyä perinnettä, ja tällöin sen on koettu muodostavan uhan kulttuuriperinnölle. Toisaalta yhteys on mielletty myös positiivisena asiana, sillä sen on nähty toimivan globalisoituvassa maailmassa kulttuuriperintöä, kulttuuria ja kansanperinnettä säilyttävänä tekijänä. Väitöskirjassa tutkitaan sitä, miten kulttuuriperintö ilmenee Dracula-turismissa Romaniassa. Dracula- turismi on turismia, joka liittyy joko fiktiiviseen vampyyrikreivi Draculaan tai historiallisena Draculana tunnettuun romanialaiseen hallitsijaan Vlad Seivästäjään. Väitöskirjan päätutkimuskysymyksenä on, miten romanialaista kulttuuriperintöä ja kulttuuria voidaan tuoda esiin näennäisesti pinnallisen ja länsimaiseen populaarikulttuuriin pohjautuvan Dracula-turismin kautta. Työn päälähteet pohjautuvat tutkijan vuosina 2010 ja 2011 tekemiin kenttätöihin sekä kymmenen Dracula-turismia tarjoavan romanialaisen matkatoimiston WWW-sivustoihin. Internet-sivuilta löytyvät tarinat ja kuvat sekä matkaoppaiden käyttämät tarinat muodostavat tutkimuksen tutkimusaineiston. Tutkimuksen painotus ja näkökulma ovat folkloristisia. Tutkimuksen teoreettinen viitekehys muodostuu kriittisestä diskurssianalyysistä sekä multimodaalisesta diskurssianalyysistä. Näiden lisäksi tutkimusaineistoa analysoidaan intertekstuaalisuuden, folkloreprosessin, hybridisaation, autenttisuuden ja sosiaalisen konstruktion käsitteiden avulla. Väitöskirjatutkimus tarjoaa uusia näkökulmia turismia ja kulttuuriperintöä käsittelevään tutkimukseen sekä tarjoaa matkailun tutkimukseen folkloristisen lisänäkökulman. Folkloristisen tutkimuksen näkökulmasta työn keskiössä ovat perinteen ja folkloren hyödyntäminen sekä autenttisuuden käsitteen määrittely ja käyttö, joihin työssä otetaan kantaa. Vaikka tutkimus käsittelee Dracula-turismia Romaniassa, ovat tutkimustulokset käytettävissä ja sovellettavissa myös laajemmin. Työn keskeiset tutkimustulokset osoittavat, että kulttuuriperintö ilmenee Dracula-turismissa kolmella eri tavalla: ylätasolla kuten esimerkiksi UNESCO:n kohteissa, alatasolla paikallisten ihmisten tai ihmisryhmien määrittelemänä sekä vastustuksen muotona. Väitöskirjassa tutkitut matkatoimistot käyttävät Dracula-turismia ikään kuin porttina romanialaiseen historiaan, kulttuuriin, perinteeseen ja kulttuuriperinteeseen.

Designing sustainable industrial ecosystems : the case of a biogas-for-traffic solution

This thesis focuses on the development of sustainable industrial architectures for bioenergy based on the metaphors of industrial symbiosis and industrial ecosystems, which imply exchange of material and energy side-flows of various industries in order to improve sustainability of those industries on a system level. The studies on industrial symbiosis have been criticised for staying at the level of incremental changes by striving for cycling waste and by-flows of the industries ‘as is’ and leaving the underlying industry structures intact. Moreover, there has been articulated the need for interdisciplinary research on industrial ecosystems as well as the need to extend the management and business perspectives on industrial ecology. This thesis addresses this call by applying a business ecosystem and business model perspective on industrial symbiosis in order to produce knowledge on how industrial ecosystems can be developed that are sustainable environmentally and economically. A case of biogas business is explored and described in four research papers and an extended summary that form this thesis. Since the aim of the research was to produce a normative model for developing sustainable industrial ecosystems, the methodology applied in this research can be characterised as constructive and collaborative. A constructive research mode was required in order to expand the historical knowledge on industrial symbiosis development and business ecosystem development into the knowledge of what should be done, which is crucial for sustainability and the social change it requires. A collaborative research mode was employed through participating in a series of projects devoted to the development of a biogas-for-traffic industrial ecosystem. The results of the study showed that the development of material flow interconnections within industrial symbiosis is inseparable from larger business ecosystem restructuring. This included a shift in the logic of the biogas and traffic fuel industry and a subsequent development of a business ecosystem that would entail the principles of industrial symbiosis and localised energy production and consumption. Since a company perspective has been taken in this thesis, the role of an ecosystem integrator appeared as a crucial means to achieve the required industry restructuring. This, in turn, required the development of a modular and boundary-spanning business model that had a strong focus on establishing collaboration among ecosystem stakeholders and development of multiple local industrial ecosystems as part of business growth. As a result, the designed business model of the ecosystem integrator acquired the necessary flexibility in order to adjust to local conditions, which is crucial for establishing industrial symbiosis. This thesis presents a normative model for the development of a business model required for creating sustainable industrial ecosystems, which contributes to approaches at the policy-makers’ level, proposed earlier. Therefore, this study addresses the call for more research on the business level of industrial ecosystem formation and the implications for the business models of the involved actors. Moreover, the thesis increases the understanding of system innovation and innovation in business ecosystems by explicating how business model innovation can be the trigger for achieving more sustainable industry structures, such as those relying on industrial symbiosis.

Persistent organic pollutants in sediments and fish from Lake Victoria, Uganda

This thesis describes the occurrence and sources of selected persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and hexachlorocyclohexanes (HCHs) in the northern watershed of Lake Victoria. Sediments and fish were collected from three highly polluted embayments (i.e. Murchison Bay, Napoleon Gulf and Thurston Bay) of the lake. The analysis for PCDD/Fs, PCBs and PBDEs was done using a high resolution mass spectrometer coupled to a gas chromatograph (GC), and a GC equipped with an electron capture detector was used for HCHs. Total (Σ) PCDD/Fs, PCBs and PBDEs in sediments ranged from 3.19 to 478, 313 to 4325 and 60.8 to 179 pg g-1 dry weight (dw), respectively. The highest concentrations of pollutants were found at sites close to industrial areas and wastewater discharge points. The maximum concentrations of PCDD/Fs, PCBs, PBDEs and HCHs in fish muscle homogenates were 49, 779, 495 and 45,900 pg g-1 wet weight (ww), respectively. The concentrations of the pollutants in Nile perch (Lates niloticus) were significantly greater than those in Nile tilapia (Oreochromis niloticus), possibly due to differences in trophic level and dietary feeding habits among fish species. World Health Organization-toxic equivalency quotient (WHO2005-TEQ) values in the sediments were up to 4.24 pg g-1 dw for PCDD/Fs and 0.55 pg TEQ g-1 dw for the 12 dioxin-like PCBs (dl-PCBs). 23.1% of the samples from the Napoleon Gulf were above the interim sediment quality guideline value of 0.85 pg WHO-TEQ g-1 dw set by the Canadian Council for Ministers of the Environment. The WHO2005-TEQs in fish were 0.001-0.16 pg g-1 for PCDD/Fs and 0.001-0.31 pg g-1 ww for dl- PCBs. The TEQ values were within a permissible level of 3.5 pg g−1 ww recommended by the European Commission. Based on the Commission set TEQs and minimum risk level criteria formulated by the Agency for Toxic Substances and Disease Registry, the consumption of fish from Lake Victoria gives no indication of health risks associated to PCDD/Fs and PCBs. Principal component analysis (PCA) indicated that anthropogenic activities such as agricultural straw open burning, medical waste incinerators and municipal solid waste combustors were the major sources of PCDD/Fs in the watershed of Lake Victoria. The ratios of α-/γ-HCH varied from 0.89 to 1.68 suggesting that the highest HCH residues mainly came from earlier usage and fresh γ-HCH (lindane). In the present study, the concentration of POPs in fish were not significantly related to those in sediments, and the biota sediment accumulation factor (BSAF) concept was found to be a poor predictor of the bioavailability and bioaccumulation of environmental pollutants.

Study of the aging of fermented of yacon (Smallanthus sonchifolius) and sensory profile and acceptance

Yacon is considered a functional food due to its the fructooligosaccharide (FOS) content, however its perishability and low production volume is a problem. The aim of this study was to analyze the changes in aging during one year of storage and conduct sensory analysis of fermented of yacon. For one year total acidity, volatile acidity, free and total sulfur dioxide, reducing sugars, sucrose, phenols and FOS and its antioxidant power were studied. At the end of aging a sensory profile and acceptance panel was performed. The total and volatile acidity increased significantly (p < 0.05). A decrease in fructooligosaccharide was also observed, indicating that yeasts are probably capable of hydrolyzing the latter. The total sulfur dioxide decreased significantly, demonstrating its ability to act well against oxidation products. This product showed good antioxidant capacity and sensory profiles of considerable acceptance. Therefore it can be affirmed that the alcoholic fermentation of yacon can be a good alternative for the industrial sector and farmers in the region could be encouraged to use large-scale production.

Chemical composition, fatty acid profile and bioactive compounds of guava seeds (Psidium guajava L.)

This study aimed to characterize the chemical composition, determine the fatty acid profile, and quantify the bioactive compounds present in guava seed powder (Psidium guajava L.). The powder resulted from seeds obtained from guava pulp processing. The agro-industrial seeds from red guava cv. paluma were used, and they were donated by a frozen pulp fruit manufacturer. They contain varying amounts of macronutrients and micronutrients, with a high content of total dietary fiber (63.94 g/100g), protein (11.19 g/100g), iron (13.8 mg/100g), zinc (3.31 mg/100g), and reduced calorie content (182 kcal/100g). Their lipid profile showed a predominance of unsaturated fatty acids (87.06%), especially linoleic acid (n6) and oleic acid (n9). The powder obtained contained significant amounts of bioactive compounds such as ascorbic acid (87.44 mg/100g), total carotenoids (1.25 mg/100 g) and insoluble dietary fiber (63.55 g/100g). With regard to their microbiological quality, the samples were found suitable for consumption. Based on these results, it can be concluded that the powder produced has favorable attributes for industrial use, and that use of these seeds would be a viable alternative to prevent various diseases and malnutrition in our country and to reduce the environmental impact of agricultural waste.

Physicochemical properties, modifications and applications of starches from different botanical sources

Present trends towards technologies and processes that increase the use of residues make starchy vegetal biomass an important alternative material in various applications due to starch’s versatility, low cost and ease of use when its physicochemical properties are altered. Starch is increasingly used in many industrial applications and as a renewable energy resource. Starch can be modified to enhance its positive attributes and eliminate deficiencies in its native characteristics. In this article, the state of knowledge on conventional and unconventional starches and their properties, characteristics, modifications and applications are reviewed.