4,161 research outputs found
Estimation of the maximal heart rate for exercise prescription in heart failure patients: are we there yet?
No full textExercise prescription for heart failure (HF) is a cornerstone for a clinically effective and safe cardiac rehabilitation (CR) programme. 1,2 Likewise, the prescription of the intensity according to the ventilatory thresholds, identified by cardiopulmonary exercise testing (CPET), is considered an optimal method. 2-4 Although with lower accuracy, when CPET is not available, a percentage of the measured maximal heart rate (MHR) during an exercise stress test (EST) is considered the minimum standard in recent CR guidelines worldwide. 2,3 However, professionals must be prepared to safely assess and monitor patients when this assessment is unavailable 5 since the evidence shows that most centres are still not performing this evaluation prior to beginning CR. 6 Thus, in the absence of maximal tests (CPET or EST) or a submax-imal volitional test (field and submaximal tests), the rating of perceived exertion and the talk test are two commonly recommended techniques to estimate the intensity for appropriate exercise prescription since the determination according to a percentage of the predicted MHR can be highly divergent in HF patients, mainly due to negative chronotropic influence of the beta-blockers, and disease-related dysfunctions. 2 A recent study by Magrì et al. 7 developed a new equation for MHR prediction in HF patients with reduced left ventricular ejection fraction (LVEF) and treated with beta-blockers. According to this cohort including 3487 stable HF subjects, the equation utilizes four variables [e.g. age, rest heart rate (HR), LVEF, and anaemia], as following [MHR = (109-(0.5 × age) + (0.5 × rest HR) + (0.2 × LVEF)-(5 if haemoglobin <11 g/ dL)]. The derived equation improved historical and cohort-based, most routinely used formulas, which can be valuable to determine the real maximal effort during an EST when the CPET is unavailable. The authors also concluded that a percentage range of 75-80% of the MHR, deriving from the new equation, might help to identify the intensity domains during a CR programme. The authors are applauded for the massive amount of work that has been put into this study, aiming to provide a clinically relevant toll with the best accuracy possible to be utilized in daily practice; however, despite the unquestionable relevance of the research, we felt that its indiscriminate use for exercise prescription should be evaluated with caution. Although more acceptable, the coefficient of determination provided with the new equation remained low (r 2 = 0.24) and the standard error high (17.5 b.p.m.), indicating that independent selected variables (age, rest HR, LVEF, and anaemia) are not explaining much the variation on the MHR for the majority of the patients (76%). The increased dispersion may generate substantial imprecision in exercise prescription domain identification, hereby potentially precluding its large-scale clinical use, particularly on those with different phenotypes and co-morbidities than those assessed in the study. Hansen et al. 8 have already demonstrated that even the intensity domains prescribed according to a percentage of a measured MHR can be extremely incompatible with the current guideline-based recommendations due to individual HR scattering in response to exercise. Likewise, an exercise intensity determination according to an estimated MHR can generate greater inconsistencies , lowering CR prescription accuracy, which may also decrease safety and efficacy. Hence, considering the importance of assessing the reproducibility and generalizability of prediction models, we felt that external validation of the equation from Magrì et al. 7 could be relevant. To assess the new equation applicability, we obtained the MHR of a sample of 191 HF patients with reduced LVEF (age: 55.8 ± 13.7 years; 69.6% male; body mass index 27.0 ± 4.5 kg/m 2) retrospectively assessed on treadmill CPET exams performed in a private outpatient cardiologic clinic in Brazil. These data are part of a multicentric study, approved by the institutional review board under number CAAE: 35706720.4.0000.8093. All patients continued beta-blocker treatment and achieved maximal effort (respiratory exchange ratio of 1.05 or higher) during the stress test and were in sinus rhythm. Heart failure was secondary to coronary artery disease in 51.3% of the cohort, with an average LVEF of 38.3 ± 6.7%. Conclusively, the median and interquartile range of the measured MHR was 135 (114-155) b.p.m., while the estimated MHR by Keteyian et al. 9 was 119 (114-126) b.p.m. and by the new equation 7 121 (116-128) b.p.m. These groups were compared by the post hoc for multiple comparisons as appropriate. Interestingly, the estimated MHR from both formulas (Keteyian et al. 9 and the new formula 7) were not statistically different from each other (P = 0.11), and the measured MHR was different from both estimation's formulas (P < 0.01 and P < 0.01). The association between measured and estimated MHR was assessed by the Spearman correlation coefficient, which revealed a moderate correlation between the measured and estimated values (rho = 0.576 for Keteyian and 0.592 for Magrì). Finally, the agreement between the measured and estimated MHR, assessed byFinancial partial support for this work was provided by public research grants and scholarships from Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Aspetti tecnico-funzionali e applicativi della comunicazione mobile
No full textVengono analizzate le applicazioni più significative dei sistemi radiomobili privati, sia in ambito nazionale che europeo, al fine di individuare le variabili organizzative e tecnico-funzinali che le caratterizzano. Tali variabili vengono poi utilizzate per definire una classificazione che permetta di astrarsi dall'ambito specifico di ciascuna applicazione. Tale classificazione vuole essere un supporto ed una guida nel fornire delle indicazioni generali e degli orientamenti sulle possibili architetture di un sistema adottabile dalle aziende interessate
Cuentas personales de Tomás Cipriano de Mosquera
No full textFacturas de diez cajas que Tomás Cipriano de Mosquera envió a Torlonia y Cía. para ser expedidas a Livourne; marcadas y numeradas como se requiere a la consignación de G. E. L. Willerding. Fechadas en Roma
Agrigento. L’ipogeo P nella necropoli paleocristiana della Valle dei Templi. Ricerche 2005-2012
No full textSi presentano i risultati dello scavo e degli studi condotti su l'ipogeo P di Agrigento. Si tratta dell'unico ipogeo paleocristiano interamente indagato e studiato nell'ambito della collaborazione tra Università degli studi di Palermo e Parco archeologico e paesaggistico della Valle dei Templi. L'ipogeo ha avuto una lunga utilizzazione a scopo funerario dal Iv a tutto il VII secolo; quindi rientra nel processo di abbandono e distruzione del cimitero cristiano e di rifunzionalizzazione di alcuni spazi dello stesso per l'impianto di una officina ceramica medievale
Schede nn. 111, 114, 115, 118, 123, 125, 126, 127, 128, 129, 130 (OHrringe; Guertelschnalle; Fingerring; Anhaenger; Brustkreuz; Oellampe mit Himmelfahrtsdarstellung; Oellampe mit Widderdarstellung; Afrikanische Oellampe mit Gemmenkreuzdarstellung; Afrikanische Oellampe mit Monogrammkreuzdarstellung; Afrikanische Oellampe mit Viktoriadarstellung; Afrikanische Oellampe mit Fischdarstellung
No full textSchede su elementi di corredo funzionale e personale rinvenuti nelle sepolture di alcuni cimiteri tardoantichi della Sicili
La catacomba di Villagrazia di Carini e il problema della ecclesia carinensis. I risultati delle recenti esplorazioni.
No full textCARRA R.M, CAVALLARO N, CIPRIANO G, FALZONE G, MORFINO D, VITALE E (2007). La catacomba di Villagrazia di Carini e il problema dell''ecclesia carinensis. I risultati delle recenti esplorazioni. In: CARRA R.M., VITALE E. A CURA DI. La cristianizzazione in Italia fra tardo antico ed altomedioevo. vol. II, p. 1837-1923, PALERMO:Carlo Saladino Editore, ISBN: 978-88-95346-08-3
EMMA VITALE
LO SCAVO DELLE GALLERIE VII-XIII, PP. 1856-1867
Il contributo presenta i risultati delle campagne di scavo nel cimitero ipogeo di Villagrazia di Carini dal 2000 al 2006, e gli esiti dell’analisi strutturale condotta in tutti i settori in cui l’indagine archeologica è stata completata. Tutto il cimitero, all’inizio delle esplorazioni, si presentava completamente ostruito da spessi strati di riempimento alluvionale provenienti dal vicino Torrente delle Grazie, il cui alveo fu cementificato verso la fine degli anni Ottanta del Novecento.
Le gallerie VII-XIII costituiscono una lunga arteria Nord-Sud da cui diramano tutti gli altri settori del cimitero finora indagati. All’incrocio dei corridoi si trovano ampi lucernai, che in antico fornivano aria e luce all’area funeraria; da qui, dopo l’abbandono della catacomba, si sono infiltrati gli strati di riempimento che hanno completamente invaso tutto il monumento fino all’inizio dell’esplorazione archeologica, promossa a partire dall’anno 2000 dalla Cattedra di Archeologia Cristiana dell’Università di Palermo e dalla Pontificia Commissione di Archeologia Sacra.
Lo scavo ha determinato la rimozione di tutti gli interri alluvionali fino a mettere in luce per intero, nei settori VII-XIII, tutte le sepolture parietali e, in alcuni punti, i livelli pavimentali.
Per la prima volta è stato, così, possibile procedere alla classificazione delle sepolture parietali e pavimentali secondo gli attuali criteri tipologici, facenti essenzialmente riferimento alla ricchissima documentazione presente nei cimiteri di Roma e del Lazio. I tipi funerari individuati sono: 1) l’arcosolio per adulto, con un numero di arche (fosse) al suo interno variabile da 1 (arcosolio monosomo) a più di 3 (polisomo); 2) l’arcosolio per infante e per bambino, di norma monosomo e spesso dotato di una ricca decorazione ad affresco; 3) la tomba “a mensa”, in cui la nicchia che sormonta la fossa è di taglio arcuato; 4) il loculo, attestato a Villagrazia in un numero esiguo casi; 5) la fossa terragna o forma, scavata nel piano pavimentale delle gallerie e chiusa da due-tre lastroni di calcarenite ricoperti da diversi strati di intonaco sempre più diluito ed accuratamente lisciato al fine di preservare al meglio la deposizione dall’umidità e dall’usura dei passi dei frequentatori del cimitero.
La Galleria X, in particolare, si è rivelata di particolare importanza sia sotto il profilo topografico che per l’aspetto progettuale. In continuazione della GVII, questo corridoio costituisce l’asse portante della catacomba, come rivela il suo impianto generale contraddistinto dalla regolarità e dallo sfruttamento ordinato e razionale degli spazi, che si riassume nelle caratteristiche qui di seguito elencate: 1) Presenza di grandi arcosoli monumentali ad altezza d’uomo simmetricamente affrontati lungo entrambe le pareti della galleria, e di arcosoli più piccoli, destinati a sepolture di bambini, nei diaframmi di roccia in alto vicino alla volta. 2) Coppie di arcosoli per bambini in pile ordinate di due o tre, specialmente presso gli spigoli della galleria. 3) Ricerca di nuovi spazi nel rispetto dell’impianto originario, mediante la trasformazione di alcuni arcosoli in cubicoli, spazi privatizzati per una committenza privilegiata. 4) Superfici lisciate o scolpite (ghiere) per ricevere una decorazione dipinta o un rivestimento parietale; segni incisi direttamente sulla parete rocciosa.
La GX, obliterata per secoli da forti interri alluvionali conserva, dunque, quei tratti strutturali e decorativi dell’originario impianto del cimitero che risultano, oggi, molto meno riconoscibili negli altri settori, irrimediabilmente manomessi dall’impianto di strutture produttive a partire dal tardo Medioevo (opificio per la cannamele) e fino ai nostri giorni
La decorazione pittorica nei contesti funerari della Sicilia. III-V sec. d.C.
No full textAnalisi iconografcia e stilistica degli apparati pittorici presenti nei cimiteri tardoantichi della Sicili
Exercise intensity domains determined by heart rate at ventilatory threshold: a comparison of the guideline-directed exercise intensity domains for cardiovascular rehabilitation prescription
No full textThe user has requested enhancement of the downloaded file.Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
INSIDE THE NEXUS: EXPLORING PERSONAL MOTIVATIONS AND ENTREPRENEURIAL OPPORTUNITIES WITHIN HIGH-TECH EMERGING VENTURES
No full textThis doctoral thesis aims to contribute to open a black box called “nexus”. Shane and Venkataraman (2000) assert that entrepreneurship consists of “the nexus of two phenomena: the presence of lucrative opportunities and the presence of enterprising individuals”. Since their work, few authors tried to describe the “nexus” because its complexity and because it can be considered the real ‘ignition spark’ of every ntrepreneurial experience. In this thesis, we will try to explore this nexus, focusing on two main components. The joint investigation of individuals and opportunities is a critical
research path in order to better clarify the mechanisms and the essence of entrepreneurial behaviours and actions avidsson 2008). Therefore from one hand we explore the relevant entrepreneurial motivations that drive the ntrepreneurial choices within high-tech emerging ventures. On the other hand we investigate the nature of entrepreneurial opportunities, by asking if high-tech entrepreneurs recognize or create the technological opportunities that they exploit. In this work a motivation is defined as the activator of a goal oriented behaviour. From a
selective review of the literature we note insufficient consideration of the role of the human motivations in the entrepreneurial process within the recent entrepreneurship research. Environmental factors being held constant, human motivation plays a critical role in the entrepreneurial process (Shaneet al. 2003). Classical motivational theories like those by Ajzen, Herzberger and Vroom, can be partially exploited as interpretative frameworks for the entrepreneurial process. According to Shane, Collins and Locke (2003) and to Davidsson (2008), the specificity of entrepreneurial phenomena requires dedicated investigation.
The first research question is thus the following. What are the relevant entrepreneurial motivations that drive the entrepreneurial choice within high-tech emerging ventures? How and why motivations change in the phases of life of the firm? We investigate the main motivational driver of
high-tech entrepreneurs and eventually we want to identify the mechanism that lead the eventual change of repreneurial motivations.Recent Entrepreneurship research dedicated great attention to the construct called “entrepreneurial opportunity”. (Shane and Venkataraman 2000, ,Sarasvathy et al. 2003, Alvarez and Barney, 2006, Plummer et al. 2007, Davidsson 2008, Harms et al. 2009) Entrepreneurial pportunities are defined as those situations in which new goods, services, raw materials, and organization methods
can be introduced in the market and sold at greater than their cost of production (Casson 1982). As far as their epistemological and the ontological features are concerned, two opposite views are available. Opportunities are like mushrooms in the forest (Davidsson 2008) Because of individual differences and information asymmetries all actors do not have access to exactly the same opportunities. This is the core of the “Discovery school”: although recognition of opportunities is a subjective process, the opportunities themselves are objective phenomena that are not known to all parties at all time (Venkataraman 1997, Shane and Venkataraman 2000 AMR, Shane and Eckhardt 2003) The second view is called Creative School: opportunities are created in the entrepreneur’s mind and it is not meaningful to talk about these opportunities separated from their creators. Venture ideas are internally generated based on more or less explicit and correct perceptions of external conditions. (Baker and Nelson 2005,) opportunities do not exist objectively , but are subjectively enacted (Gartner et al. 2001,Sarasvathy 001,2008). Is any reconciliation between the two schools possible? The second question is, thus, the following. Do entrepreneurs recognize or create technological pportunities?. How the two processes – recognition and creation – come off? We are not going to propose a reconciliation theory: our aim is to demonstrate that both the perspectives are practically relevant and thus a general theory of entrepreneurship should take into account the dichotomous nature of entrepreneurial opportunities, distinguishing between objective opportunities and effectually created opportunities.
Both qualitative (case studies) and quantitative (survey) approaches have been planned in order to answer to the research questions presented by this doctoral thesis. Quantitative data should be collected through a survey, sent to the firms of the database Veneto High-Tech (which is described in this thesis). Unfortunately the response rate has been too low.
Case studies accord to the suggestions proposed by Eisenhardt (1989), Yin (2002), Gummeson (2006) and Flyvberg (2006). The exploratory nature of this study suggests the use of a qualitative methodological approach, and in particular the multiple case studies . Multiple case studies research is a useful tool to understand the complex nature of entrepreneurship, as recommended by Gartner and
Birley (2002). The cases have been strategically selected within the considered population (Veneto High-Tech atabase), according to Flyvberg (2006) on basis of size, industry, products, innovative activities, geographical equilibrium and personal knowledge of the entrepreneur. The main limit of this
approach is the possibility to present general determinants of phenomena through a limited number of cases. As we will see below, the cases are based of semi-structured interviews with entrepreneurs. A single case study for every enterprise by the researcher, in order to summarize and better fix the
interviews and the entrepreneur words. A feedback echanism: every single case should be read ,
rectified or amended by the people who has been interviewed. The Nvivo 8 software tool has been used
in order to collect and analyze qualitative data.
The cross case comparison lead us to propose a hierarchical assessment of the motivational drivers.
At individual level the basic motivations that emerge from the cases are the following: a) family
environment, b) necessity (lack of job or not satisfying job alternatives), c)McClelland (1961)
indicators (N-Pow, N-Ach, N-Aff), d) financial return. Once one or more of these motivations are
considered relevant from a potential entrepreneur, other motivational aspects can enrich the reasons for
the Entrepreneurial Choice and the daily effort of the entrepreneur. We asses them as 1) product level motivations: desire to demonstrate the feasibility of the technology applied in the product, f) desire to demonstrate the profitability of the technology applied in the product 2) strategy-level motivations: , g) desire to be innovative h) desire to iversificate and increase the portfolios of products, i) intention to maintain the technological leadership,3) personal responsibility motivations: l) creation of wealth (jobs, legacy, knowledge), m) corporate social responsibility issues.
From a practical point of view the hierarchical assessment of the entrepreneurial motivations can be used for many purposes: 1)as tool for the self-evaluation of motivations, 2)as reference scheme for entrepreneurship education
From the cross comparison we identified three wide categories of entrepreneurial opportunities: 1) technological paradigms with a broad spectrum of potential application
2) niche technologies or specific applications of general technological paradigms that solve a particular problem, leading to a new product or process 3) the market. The case studies suggest that the market is viewed by entrepreneurs as a differential opportunity.Several opportunities which present an objective existence can be identified within the case studies. These opportunities have been recognized and exploited through the process described by Shane (2003). This evidence confirms the ontological and epistemological perspective offered by the so called
“Discovery School”. Furthermore in some case studies is evident the presence of effectual logic (Sarasvathy 2001, 2008), as driving logic of the ntrepreneurial decision making process. The entrepreneurs act both causally and effectually. This fact lead us to confirm the idea that some opportunities exist only in the entrepreneurs’ mind and thus they are created by the entrepreneur herself/himself. We demonstrate, as far as high-tech entrepreneurship is concerned, the co-existence of two processes: recognition and creation. A powerful general theory of entrepreneurship should take into account both of them, and should try to reconcile the Creative and the Discovery School. Unifying two ontological and epistemological perspectives is a true challenge that the community of scholars and researcher is requested to face.This doctoral thesis aims to contribute to open a black box called ânexusâ. Shane and Venkataraman (2000) assert that entrepreneurship consists of âthe nexus of two phenomena: the presence of lucrative opportunities and the presence of enterprising individualsâ. Since their work, few authors tried to describe the ânexusâ because its complexity and because it can be considered the real âignition sparkâ of every entrepreneurial experience. In this thesis, we will try to explore this nexus, focusing on two main components. The joint investigation of individuals and opportunities is a critical research path in order to better clarify the mechanisms and the essence of entrepreneurial behaviours and actions (Davidsson 2008). Therefore from one hand we explore the relevant entrepreneurial motivations that drive the entrepreneurial choices within high-tech emerging ventures. On the other hand we investigate the nature of entrepreneurial opportunities, by asking if high-tech entrepreneurs recognize or create the technological opportunities that they exploit.
In this work a motivation is defined as the activator of a goal oriented behaviour. From a selective review of the literature we note insufficient consideration of the role of the human motivations in the entrepreneurial process within the recent entrepreneurship research. Environmental factors being held constant, human motivation plays a critical role in the entrepreneurial process (Shane et al. 2003). Classical motivational theories like those by Ajzen, Herzberger and Vroom, can be partially exploited as interpretative frameworks for the entrepreneurial process. According to Shane, Collins and Locke (2003) and to Davidsson (2008), the specificity of entrepreneurial phenomena requires dedicated investigation.
The first research question is thus the following. What are the relevant entrepreneurial motivations that drive the entrepreneurial choice within high-tech emerging ventures? How and why motivations change in the phases of life of the firm? We investigate the main motivational driver of high-tech entrepreneurs and eventually we want to identify the mechanism that lead the eventual change of entrepreneurial motivations.
Recent Entrepreneurship research dedicated great attention to the construct called âentrepreneurial opportunityâ. (Shane and Venkataraman 2000, ,Sarasvathy et al. 2003, Alvarez and Barney, 2006, Plummer et al. 2007, Davidsson 2008, Harms et al. 2009) Entrepreneurial opportunities are defined as those situations in which new goods, services, raw materials, and organization methods can be introduced in the market and sold at greater than their cost of production (Casson 1982). As far as their epistemological and the ontological features are concerned, two opposite views are available. Opportunities are like mushrooms in the forest (Davidsson 2008) Because of individual differences and information asymmetries all actors do not have access to exactly the same opportunities. This is the core of the âDiscovery schoolâ: although recognition of opportunities is a subjective process, the opportunities themselves are objective phenomena that are not known to all parties at all time (Venkataraman 1997, Shane and Venkataraman 2000 AMR, Shane and Eckhardt 2003) The second view is called Creative School: opportunities are created in the entrepreneurâs mind and it is not meaningful to talk about these opportunities separated from their creators. Venture ideas are internally generated based on more or less explicit and correct perceptions of external conditions. (Baker and Nelson 2005,) opportunities do not exist objectively , but are subjectively enacted (Gartner et al. 2001, Sarasvathy 2001,2008)
. Is any reconciliation between the two schools possible? The second question is, thus, the following. Do entrepreneurs recognize or create technological opportunities?. How the two processes â recognition and creation â come off? We are not going to propose a reconciliation theory: our aim is to demonstrate that both the perspectives are practically relevant and thus a general theory of entrepreneurship should take into account the dichotomous nature of entrepreneurial opportunities, distinguishing between objective opportunities and effectually created opportunities.
Both qualitative (case studies) and quantitative (survey) approaches have been planned in order to answer to the research questions presented by this doctoral thesis. Quantitative data should be collected through a survey, sent to the firms of the database Veneto High-Tech (which is described in this thesis). Unfortunately the response rate has been too low.
Case studies accord to the suggestions proposed by Eisenhardt (1989), Yin (2002), Gummeson (2006) and Flyvberg (2006). The exploratory nature of this study suggests the use of a qualitative methodological approach, and in particular the multiple case studies . Multiple case studies research is a useful tool to understand the complex nature of entrepreneurship, as recommended by Gartner and Birley (2002). The cases have been strategically selected within the considered population (Veneto High-Tech database), according to Flyvberg (2006) on basis of size, industry, products, innovative activities, geographical equilibrium and personal knowledge of the entrepreneur. The main limit of this approach is the possibility to present general determinants of phenomena through a limited number of cases.
As we will see below, the cases are based of semi-structured interviews with entrepreneurs. A single case study for every enterprise by the researcher, in order to summarize and better fix the interviews and the entrepreneur words. A feedback mechanism: every single case should be read , rectified or amended by the people who has been interviewed. The Nvivo 8 software tool has been used in order to collect and analyze qualitative data.
The cross case comparison lead us to propose a hierarchical assessment of the motivational drivers. At individual level the basic motivations that emerge from the cases are the following: a) family environment, b) necessity (lack of job or not satisfying job alternatives), c)McClelland (1961) indicators (N-Pow, N-Ach, N-Aff), d) financial return. Once one or more of these motivations are considered relevant from a potential entrepreneur, other motivational aspects can enrich the reasons for the Entrepreneurial Choice and the daily effort of the entrepreneur. We asses them as
1) product level motivations: desire to demonstrate the feasibility of the technology applied in the product, f) desire to demonstrate the profitability of the technology applied in the product
2) strategy-level motivations: , g) desire to be innovative h) desire to diversificate and increase the portfolios of products, i) intention to maintain the technological leadership,
3) personal responsibility motivations: l) creation of wealth (jobs, legacy, knowledge), m) corporate social responsibility issues.
From a practical point of view the hierarchical assessment of the entrepreneurial motivations can be used for many purposes: 1)as tool for the self-evaluation of motivations, 2)as reference scheme for entrepreneurship education
From the cross comparison we identified three wide categories of entrepreneurial opportunities:
1) technological paradigms with a broad spectrum of potential application
2) niche technologies or specific applications of general technological paradigms that solve a particular problem, leading to a new product or process
3) the market. The case studies suggest that the market is viewed by entrepreneurs as a differential opportunity.
Several opportunities which present an objective existence can be identified within the case studies. These opportunities have been recognized and exploited through the process described by Shane (2003). This evidence confirms the ontological and epistemological perspective offered by the so called âDiscovery Schoolâ. Furthermore in some case studies is evident the presence of effectual logic (Sarasvathy 2001, 2008), as driving logic of the entrepreneurial decision making process. The entrepreneurs act both causally and effectually. This fact lead us to confirm the idea that some opportunities exist only in the entrepreneursâ mind and thus they are created by the entrepreneur herself/himself. We demonstrate, as far as high-tech entrepreneurship is concerned, the co-existence of two processes: recognition and creation. A powerful general theory of entrepreneurship should take into account both of them, and should try to reconcile the Creative and the Discovery School. Unifying two ontological and epistemological perspectives is a true challenge that the community of scholars and researcher is requested to face
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