101,881 research outputs found
Analisi della posizione di “iscritto”
No full textDa alcuni decenni l’università italiana è rappresentata come un sistema attraversato da una profonda contraddizione. Temi quali l’abbandono, il ritardo negli studi, il basso numero di laureati e il carente collegamento con il mondo del lavoro ricorrono frequentemente nel dibattito politico, sociale e accademico del nostro Paese. Altrettanto frequentemente, però, viene sottolineata la capacità da parte dei nostri atenei di formare laureati preparati, capaci, dotati di profili formativi solidi, in grado di competere almeno alla pari, se non da una posizione di superiorità, con i colleghi laureati in altri Paesi. Le aree problematiche riguardano, da un lato, l’efficienza (interpretata come rapporto tra risultati ottenuti e costi sostenuti) e, dall’altro, l’efficacia (intesa come raggiungimento degli obiettivi prefissati). Entrambe le dimensioni dipendono, con modalità differenti e a diversi livelli di responsabilità, sia dalle logiche del sistema universitario sia dalle politiche in materia di istruzione e formazione, nonché dall’assetto economico e dalla capacità di assorbimento del mer-cato del lavoro. Questa contraddizione appariva costitutiva di quello che oggi viene definito Vecchio ordinamento didattico. Al fine di eliminare tale stato di contraddittorio equilibrio, aumentando l’efficienza e almeno mantenendo l’efficacia, il sistema universitario italiano è stato investito negli ultimi tre lustri da radicali riforme, tra le quali la più importante per contenuti e potenziale impatto innovativo è stata introdotta dal Dm 509/1999. Il quadro ricostruibile a livello nazionale è bene rappresentato dalla situazione del più grande ateneo italiano: la Sapienza Università di Roma. Il programma di ricerca i cui risultati sono qui presentati ha, infatti, permesso di evidenziare come, a una situazione piuttosto critica nei primi anni ’90, sia seguito nel primo Ateneo romano un periodo di importanti cambiamenti. La stagione positiva della Sapienza, però, non coincide, come si potrebbe immaginare, con l’avvento della Riforma, bensì risulta anticipata di qualche anno (nel volume si parla di effetto di retroazione del Dm 509/1999). Inoltre, questo periodo di relativa prosperità è destinato a durare poco
Prolonged reticulocytopenia and transient erythroid hypoplasia in a child with autoimmune haemolytic anaemia.
No full text
Improving the characterization of meningioma microstructure in proton therapy from conventional apparent diffusion coefficient measurements using Monte Carlo simulations of diffusion MRI
No full textPurpose: Proton therapy could benefit from noninvasively gaining tumor microstructure information, at both planning and monitoring stages. The anatomical location of brain tumors, such as meningiomas, often hinders the recovery of such information from histopathology, and conventional noninvasive imaging biomarkers, like the apparent diffusion coefficient (ADC) from diffusion-weighted MRI (DW-MRI), are nonspecific. The aim of this study was to retrieve discriminative microstructural markers from conventional ADC for meningiomas treated with proton therapy. These markers were employed for tumor grading and tumor response assessment. Methods: DW-MRIs from patients affected by meningioma and enrolled in proton therapy were collected before (n = 35) and 3 months after (n = 25) treatment. For the latter group, the risk of an adverse outcome was inferred by their clinical history. Using Monte Carlo methods, DW-MRI signals were simulated from packings of synthetic cells built with well-defined geometrical and diffusion properties. Patients’ ADC was modeled as a weighted sum of selected simulated signals. The weights that best described a patient’s ADC were determined through an optimization procedure and used to estimate a set of markers of tumor microstructure: diffusion coefficient (D), volume fraction (vf), and radius (R). Apparent cellularity (ρapp) was estimated from vf and R for an easier clinical interpretability. Differences between meningothelial and atypical subtypes, and low- and high-grade meningiomas were assessed with nonparametric statistical tests, whereas sensitivity and specificity with ROC analyses. Similar analyses were performed for patients showing low or high risk of an adverse outcome to preliminary evaluate response to treatment. Results: Significant (P < 0.05) differences in median ADC, D, vf, R, and ρapp values were found when comparing meningiomas’ subtypes and grades. ROC analyses showed that estimated microstructural parameters reached higher specificity than ADC for subtyping (0.93 for D and vf vs 0.80 for ADC) and grading (0.75 for R vs 0.67 for ADC). High- and low-risk patients showed significant differences in ADC and microstructural parameters. The skewness of ρapp was the parameter with highest AUC (0.90) and sensitivity (0.75). Conclusions: Matching measured with simulated ADC yielded a set of potential imaging markers for meningiomas grading and response monitoring in proton therapy, showing higher specificity than conventional ADC. These markers can provide discriminative information about spatial patterns of tumor microstructure implying important advantages for patient-specific proton therapy workflows
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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