Market-Driven Management as Entrepreneurial Approach

Entrepreneurship is traditionally considered as an 'outward-looking' phenomenon. Entrepreneurs initiate change by identifying and starting new trading opportunities, related to improved versions of existing commodities or new product or service concepts, which have been until then unknown to other agents. Market-driven management is not posited to be an alternative to entrepreneurial management, a surrogate or even a better substitute to entrepreneurship. They are, rather, two different theoretical constructs that can be fully integrated. Value creation and appropriation within the market is the node of the relationship between entrepreneurship and market-driven management.Globalisation; Market-Driven Management; Entrepreneurial Management; Theories of the Firm; Market-Driven Intensity; Market-Space Competition; Competitive Customer Value; Value Creation

Ductilityof fiber-reinforcedself-consolidatingconcreteundermulti-axial compression

The results of 12 multi-axial compression tests performed on cylinders made of self-consolidating concrete, plain (SCC) and reinforced with steel fibers (FR-SCC), are presented. In the experimental campaign, four ‘‘reference'' confining pressures (0, 1, 3 and 10 MPa) were applied on the lateral surface of the specimens. After the first stage of loading, when a hydraulic stress was applied to the cylinders, and progressively increased up to the value of a pre-established confining pressure, a longitudinal compressive load was used to generate crushing of concrete. During this failure, the post-peak behavior of SCC and FR-SCC can be defined by a non-dimensional function that relates the inelastic displacement and the relative stress during softening. Such a function also reveals the ductility of SCC, which increases with the confinement stress and with the fiber volume fraction. In particular, by adding 0.9% in volume of steel fibers, FR-SCC can show practically the same ductility measured in unreinforced SCC with 1MPa of confining pressure. Thus, the presence of an adequate amount of fibers in SCC columns is sufficient to create a sort of distributed confinement

Dieci anni di gestione conservativa della neuro-osteoartropatia di Charcot nei pazienti diabetici: analisi retrospettica

Scopo della tesi è stato quello di descrivere l’attività ambulatoriale erogata dalla Sezione Dipartimentale del Piede Diabetico del Dipartimento di Area Medica della Asl 5 di Pisa in risposta al bisogno di salute rappresentato dalla neuro-osteoartropatia di Charcot (NOA) nella popolazione diabetica. La tesi si articola in due parti, con differenti finalità: - Studio A. Verifica degli outcomes del nostro ambulatorio di terzo livello dedicato al trattamento della NOA mediante analisi retrospettica dei dati riferiti al decennio 2002-2012. - Studio B. Valutazione comparativa prospettica dei livelli 25-OH Vitamina D, PTH, Calcio ionizzato, Osteocalcina, Fosfatasi Alcalina Ossea, S-CTX nella popolazione di pazienti afferenti al nostro ambulatorio dedicato alla NOA (sia in fase attiva che cronica) nel corso dell’anno 2012 rispetto ad un gruppo di diabetici neuropatici e ad un gruppo di diabetici non neuropatici, rispettivamente. Risultati studio A. Nell’arco di tempo stabilito sono afferiti consecutivamente presso l’ambulatorio dedicato alla NOA 205 pazienti diabetici totali. In 172 pazienti è stata effettivamente confermata l’ipotesi diagnostica di NOA, e tra questi, al momento della presa in carico, 143 pazienti presentavano una malattia in fase attiva e 29 pazienti in fase di stabilità. Tutti i pazienti in fase di attività sono stati trattati in maniera conservativa, mediante utilizzo di quattro tipologie di scarico (Total Contact Cast, Optima Diab, Aircast, Altro). L’outcome primario dello studio è stato considerato il tempo medio di stabilizzazione della NOA in fase acuta secondo le differenti modalità di scarico. Outcomes secondari sono stati considerati le riacutizzazioni di malattia, gli interventi chirurgici correttivi minori ed il tasso di amputazione maggiore. L’analisi dei dati non ha evidenziato differenze significative in termini di tempo medio di stabilizzazione tra le quattro categorie di scarico (t medio di 223,8±122,8 giorni). Durante il periodo di follow-up abbiamo osservato una riacutizzazione di malattia nel 17,3% dei pazienti stabilizzati. Nel 7,3% dei casi i pazienti cronicizzati sono stati sottoposti ad intervento chirurgico di stabilizzazione del piede; nel 4,0% dei casi si è resa necessaria l’amputazione dell’arto affetto. Nel periodo stabilito abbiamo osservato un tasso grezzo di mortalità pari al 10,4%, con un tasso di incidenza di mortalità annua pari al 3,41%. Tra le cause di morte abbiamo riscontrato gli eventi cardiovascolari maggiori (Ictus+Infarto del miocardio) nel 44,6% dei casi, ma la prima causa assoluta di morte è risultata quella secondaria a neoplasie (38,8%). Risultati studio B. Nell’arco di tempo stabilito è stato effettuato uno studio dei livelli di 25-OH Vitamina D, PTH, Calcio ionizzato, Osteocalcina, Fosfatasi Alcalina Ossea, S-CTX nelle quattro tipologie di pazienti descritte. I risultati hanno evidenziato ipovitaminosi D in tutti i gruppi con livelli significativamente inferiori nei pazienti affetti da NOA in fase acuta (8.6±3.8 ng/ml p<0.001) ed è emersa una correlazione inversamente proporzionale tra 25-OH Vitamina D e BMI. Nei quattro gruppi di pazienti non sono emerse significative differenze per i markers di neoformazione ossea. Conclusioni studio A. I risultati ottenuti dimostrano che la precoce gestione conservativa della NOA effettuata con approccio multi-specialistico integrato consente di ottenere una riduzione degli interventi chirurgici minori a carico del piede e delle amputazioni maggiori. Conclusioni studio B. La nostra analisi ha mostrato una significativa riduzione dei livelli di 25-OH Vitamina D nei pazienti affetti da NOA in fase acuta. Nonostante dallo studio non sia possibile stabilire se questo dato sia un fattore di rischio o costituisca l’epifenomeno della malattia, emerge la necessità di effettuare ulteriori studi per valutare gli outcomes prodotti dalla supplementazione di alte dosi di Vitamina D nella NOA, sia in monoterapia che in associazione con i bisfosfonati

Evaluation of pelvic lymph nodes in patients with prostate cancer: the role of Diffusion Weighted MR Imaging (DW-MRI)

PURPOSE: To evaluate the role of MRI Diffusion-Weighted Imaging (DWI) to detect pelvic lymph node metastases in patients with prostate cancer (PC) candidate to radical prostatectomy and extended pelvic lymph node dissection. MATERIALS AND METHODS: From June 2011 to March 2012, 5 patients with PC (high or intermediate risk patients), were scanned before surgical treatment using a 3T MRI scanner and a 8 channel phased-array surface body coil. Imaging protocol included T2w FSE, T1w FSE and DWI sequence (b-values: 0, 500, 800, 1000 and 1500 s/mm^2). The appearance of benign and metastatic lymph nodes on the FSE MR images was analyzed by two observers in conference. The measurement of the ADC value was performed, in the following nodal stations: external iliac proximal and distal, internal iliac proximal and distal and obturatory, each on both right and left sides. RESULTS: A total of 84 lymph nodes were removed during surgery and histologically analysed. The smallest metastatic lymph node detected by this method measured 4mm on its short axis. The appearance of benign and metastatic lymph nodes on the FSE MR images was documented in terms of short axis, the long to short axis ratio, node contour and intranodal heterogeneity signal intensity, in all ten nodal stations. For each of these parameters a Grading Score system was assigned using a two-point-level score and the grade system was obtained by adding the point-level obtained for each of these 4 parameters. The Grading Score ranged from 4, indicator of benign nature, to 8, with 8 having the worst score indicator of malignant nature. The mean Grading Score was 6,46 ± 0,42 in the nodal metastatic group and 5,02 ± 0,59 in the nodal non-metastatic group ( P 4 was considered suspicious for malignancy. With the threshold score of 4, the lymph node station-based sensitivity, specificity, positive and negative predictive values and diagnostic accuracy for FSE-MRI analysis, were 100%, 19%, 29%, 100% and 39%, respectively. Mean ADC value was 0.796 ± 0,09 × 10^–3 mm^2/s in the nodal metastatic group and 1,17 ± 0,25 × 10^–3 mm^2/s in the nodal non-metastatic group ( P = 0.0008). The ADC cut-off value, obtained by the ROC curve was 0.91 × 10^–3 mm^2/s. The lymph node station-based sensitivity, specificity, PPV, NPV and diagnostic accuracy were 100%, 95,2%, 87,5%, 100% and 96,4%, respectively. CONCLUSIONS: Our preliminary data seem to suggest that DW-MRI of lymph nodes can now be performed as part of a primary tumour staging without significantly increasing the imaging time. This unique modality can help to distinguish benign from malignant lymph nodes and that it is more accurate than FSE-MRI evaluation alone. Further, large scale studies are certainly needed to confirm our initial results

Atomic and molecular far-infrared lines from high redshift galaxies

The advent of Atacama Large Millimeter-submillimeter Array (ALMA), with its unprecedented sensitivity, makes it possible the detection of farinfrared(FIR) metal cooling and molecular lines from the first galaxies that formed after the Big Bang. These lines represent a powerful tool to shed light on the physical properties of the interstellar medium (ISM) in high-redshift sources. In what follows we show the potential of a physically motivated theoretical approach that we developed to predict the ISM properties of high redshift galaxies. The model allows to infer, as a function of the metallicity, the luminosities of various FIR lines observable with ALMA. It is based on high resolution cosmological simulations of star-forming galaxies at the end of the Epoch of Reionization (z � 6), further implemented with sub-grid physics describing the cooling and the heating processes that take place in the neutral diffuse ISM. Finally we show how a different approach based on semi-analytical calculations can allow to predict the CO flux function at z > 6

On the [CII]-SFR relation in high redshift galaxies

After two ALMA observing cycles, only a handful of [CII] $158\,\mu m$ emission line searches in z>6 galaxies have reported a positive detection, questioning the applicability of the local [CII]-SFR relation to high-z systems. To investigate this issue we use the Vallini et al. 2013 (V13) model, based on high-resolution, radiative transfer cosmological simulations to predict the [CII] emission from the interstellar medium of a z~7 (halo mass $M_h=1.17\times10^{11}M_{\odot}$) galaxy. We improve the V13 model by including (a) a physically-motivated metallicity (Z) distribution of the gas, (b) the contribution of Photo-Dissociation Regions (PDRs), (c) the effects of Cosmic Microwave Background on the [CII] line luminosity. We study the relative contribution of diffuse neutral gas to the total [CII] emission ($F _{diff}/F_{tot}$) for different SFR and Z values. We find that the [CII] emission arises predominantly from PDRs: regardless of the galaxy properties, $F _{diff}/F_{tot}\leq 10$% since, at these early epochs, the CMB temperature approaches the spin temperature of the [CII] transition in the cold neutral medium ($T_{CMB}\sim T_s^{CNM}\sim 20$ K). Our model predicts a high-z [CII]-SFR relation consistent with observations of local dwarf galaxies ($0.02<Z/Z_{\odot}<0.5$). The [CII] deficit suggested by actual data ($L_{CII}<2.0\times 10^7 L_{\odot}$ in BDF3299 at z~7.1) if confirmed by deeper ALMA observations, can be ascribed to negative stellar feedback disrupting molecular clouds around star formation sites. The deviation from the local [CII]-SFR would then imply a modified Kennicutt-Schmidt relation in z>6 galaxies. Alternatively/in addition, the deficit might be explained by low gas metallicities ($Z<0.1 Z_{\odot}$).Comment: 9 pages, 6 figures, replaced with the version accepted for pubblication in Ap

Intensity mapping of [CII] from early galaxies

The intensity mapping of the [CII] 157.7 $\rm \mu$m fine-structure emission line represents an ideal experiment to probe star formation activity in galaxies, especially in those that are too faint to be individually detected. Here, we investigate the feasibility of such an experiment for $z > 5$ galaxies. We construct the $L_{\rm CII} - M_{\rm h}$ relation from observations and simulations, then generate mock [CII] intensity maps by applying this relation to halo catalogs built from large scale N-body simulations. Maps of the extragalactic far-infrared (FIR) continuum, referred to as "foreground", and CO rotational transition lines and [CI] fine-structure lines referred to as "contamination", are produced as well. We find that, at 316 GHz (corresponding to $z_{\rm CII} = 5$), the mean intensities of the extragalactic FIR continuum, [CII] signal, all CO lines from $J=1$ to 13 and two [CI] lines are $\sim 3\times10^5$ Jy sr$^{-1}$, $\sim 1200$ Jy sr$^{-1}$, $\sim 800$ Jy sr$^{-1}$ and $\sim 100$ Jy sr$^{-1}$, respectively. We discuss a method that allows us to subtract the FIR continuum foreground by removing a spectrally smooth component from each line of sight, and to suppress the CO/[CI] contamination by discarding pixels that are bright in contamination emission. The $z > 5$ [CII] signal comes mainly from halos in the mass range $10^{11-12} \,M_\odot$; as this mass range is narrow, intensity mapping is an ideal experiment to investigate these early galaxies. In principle such signal is accessible to a ground-based telescope with a 6 m aperture, 150 K system temperature, a $128\times128$ pixels FIR camera in 5000 hr total integration time, however it is difficult to perform such an experiment by using currently available telescopes.Comment: 12 pages, 10 figures. Accepted for publication in MNRA

Molecular clumps photoevaporation in ionized regions

We study the photoevaporation of molecular clumps exposed to a UV radiation field including hydrogen-ionizing photons ($h\nu > 13.6$ eV) produced by massive stars or quasars. We follow the propagation and collision of shock waves inside clumps and take into account self-shielding effects, determining the evolution of clump size and density with time. The structure of the ionization-photodissociation region (iPDR) is obtained for different initial clump masses ($M=0.01 - 10^4\,{\rm M}_\odot$) and impinging fluxes ($G_0=10^2 - 10^5$ in units of the Habing flux). The cases of molecular clumps engulfed in the HII region of an OB star and clumps carried within quasar outflows are treated separately. We find that the clump undergoes in both cases an initial shock-contraction phase and a following expansion phase, which lets the radiation penetrate in until the clump is completely evaporated. Typical evaporation time-scales are $\simeq 0.01$ Myr in the stellar case and 0.1 Myr in the quasar case, where the clump mass is 0.1 ${\rm M}_\odot$ and $10^3\,{\rm M}_\odot$ respectively. We find that clump lifetimes in quasar outflows are compatible with their observed extension, suggesting that photoevaporation is the main mechanism regulating the size of molecular outflows.Comment: 13 pages, 12 figures, accepted for publication in MNRA

Studio idraulico del Bacino di Vecchiano afferente al Lago di Massaciuccoli e interventi per ridurre le massime portate in arrivo all'impianto idrovoro

Il presente studio di tesi esamina i problemi idraulici e ambientali presenti nell’area di bonifica del bacino delle acque basse di Vecchiano, ubicato a sud del Lago di Massaciuccoli