Terminologie

Encyclopedia entry on "terminologies" and taxonomies

Thesaurus

Encyclopedia entry on lexical and conceptual "thesauri"

Numerali

Encyclopedia entry on "numerals" (from a linguistic point of view)

Modi di dire

Encyclopedia entry for "idioms" and "idiomatic expressions" in Italian

A novel function of the proneural factor Ascl1 in progenitor proliferation identified by genome-wide characterization of its targets

Proneural genes such as Ascl1 are known to promote cell cycle exit and neuronal differentiation when expressed in neural progenitor cells. The mechanisms by which proneural genes activate neurogenesis--and, in particular, the genes that they regulate--however, are mostly unknown. We performed a genome-wide characterization of the transcriptional targets of Ascl1 in the embryonic brain and in neural stem cell cultures by location analysis and expression profiling of embryos overexpressing or mutant for Ascl1. The wide range of molecular and cellular functions represented among these targets suggests that Ascl1 directly controls the specification of neural progenitors as well as the later steps of neuronal differentiation and neurite outgrowth. Surprisingly, Ascl1 also regulates the expression of a large number of genes involved in cell cycle progression, including canonical cell cycle regulators and oncogenic transcription factors. Mutational analysis in the embryonic brain and manipulation of Ascl1 activity in neural stem cell cultures revealed that Ascl1 is indeed required for normal proliferation of neural progenitors. This study identified a novel and unexpected activity of the proneural gene Ascl1, and revealed a direct molecular link between the phase of expansion of neural progenitors and the subsequent phases of cell cycle exit and neuronal differentiation.

Una biografia per immagini

Life and work of screen-writer Enrico Medioli (b. 1925), following the criteria of Dizionario Biografico degli Italiani (by Istituto Enciclopedia Italiana), tht is the top of Italian tools (I wrote several items for it).

Tapping into Floor Staff: Using the knowledge of floor staff to conduct formative evaluations of exhibits in a Canadian science centre

Most science centres in Canada employ science-educated floor staff to motivate visitorsto have fun while enhancing the educational reach of the exhibits. Although bright andsensitive to visitors’ needs, floor staff are rarely consulted in the planning,implementation, and modification phases of an exhibit. Instead, many developmentteams rely on costly third-party evaluations or skip the front-end and formativeevaluations all together, leading to costly errors that could have been avoided. This studywill seek to reveal a correlation between floor staff’s perception of visitors’ interactionswith an exhibit and visitors’ actual experiences. If a correlation exists, a recommendationcould be made to encourage planning teams to include floor staff in the formative andsummative evaluations of an exhibit. This is especially relevant to science centres withlimited budgets and for whom a divide exists between floor staff and management.In this study, a formative evaluation of one exhibit was conducted, measuring both floorstaff’s perceptions of the visitor experience and visitors’ own perceptions of the exhibit.Floor staff were then trained on visitor evaluation methods. A week later, floor staff andvisitors were surveyed a second time on a different exhibit to determine whether anincrease in accuracy existed.The training session increased the specificity of the motivation and comprehensionresponses and the enthusiasm of the staff, but not their ability to predict observedbehaviours with respect to ergonomics, learning indicators, holding power, and successrates. The results revealed that although floor staff underestimated visitors’ success ratesat the exhibits, staff accurately predicted visitors’ behaviours with respect to holdingpower, ergonomics, learning indicators, motivation and comprehension, both before andafter the staff training.

Da enciclopédia à Wikipédia: o conhecimento em circulação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cytogenetic damage related to low levels of methyl mercury contamination in the Brazilian Amazon

The mercury rejected in the water system, from mining operations and lixiviation of soils after deforestation, is considered to be the main contributors to the contamination of the ecosystem in the Amazon Basin. The objectives of the present study were to examine cytogenetic functions in peripheral lymphocytes within a population living on the banks of the Tapajós River with respect to methylmercury (MeHg) contamination, using hair mercury as a biological indicator of exposure. Our investigation shows a clear relation between methylmercury contamination and cytogenetic damage in lymphocytes at levels well below 50 micrograms/gram, the level at which initial clinical signs and symptoms of mercury poisoning occur. The first apparent biological effect with increasing MeHg hair level was the impairment of lymphocyte proliferation measured as mitotic index (MI). The relation between mercury concentration in hair and MI suggests that this parameter, an indicator of changes in lymphocytes and their ability to respond to culture conditions, may be an early marker of cytotoxicity and genotoxicity in humans and should be taken into account in the preliminary evaluation of the risks to populations exposed in vivo. This is the first report showing clear cytotoxic effects of long-term exposure to MeHg. Although the results strongly suggest that, under the conditions examined here, MeHg is both a spindle poison and a clastogen, the biological significance of these observations are as yet unknown. A long-term follow-up of these subjects should be undertaken.

Fidarsi di Wikipedia. Attacchi vandalici e resilienza dei contenuti: un modello di analisi ed alcune evidenze empiriche

Lo scopo dello studio è comprendere i fenomeni alla base della fiducia degli utenti verso l'enciclopedia online Wikipedia. Per farlo è necessario prima di tutto comprendere e modellizzare l'organizzazione della struttura dei processi socio-produttivi sottostanti alla produzione del contenuto di Wikipedia, procedendo quindi nel verificare empiricamente e descrivere le capacità di autocorrezione della stessa. Oltre a quelli utilizzati in questo studio, saranno anche descritti gli approcci e i risultati trattati in letteratura, riportando i principali studi che nel corso degli anni hanno affrontato questi argomenti, sebbene mantenendoli indipendenti. Per comprendere la struttura della community degli editor di Wikipedia, si è ipotizzata l'esistenza di un modello di tipo Core-Periphery. Per studiare il modello sono state eseguite delle analisi su dati derivanti da un campione di pagine della versione italiana di Wikipedia. I risultati ottenuti dall'analisi di queste informazioni rappresentano le basi utilizzate per la selezione delle pagine oggetto dell'iniezione degli errori, costituendo un metodo per stimare le diverse probabilità di autocorrezione per ciascuna pagina. Per quanto riguarda le capacità di resilienza di Wikipedia, i risultati sono ricavati utilizzando un approccio empirico. Questo consiste nell'inserimento di errori all'interno del campione di pagine sotto specifici vincoli metodologici per poi valutare in quanto tempo e con quali modalità questi errori vengono corretti. E' stata effettuata un'analisi specifica per la scelta delle tipologie di errore e delle variabili da considerare nell'inserimento di questi. Questa analisi ha portato alla definizione di 2 esperimenti tra loro distinti, i cui risultati portano ad interessanti conclusioni sia visti separatamente che combinati tra loro. Sulla base dei risultati di questi esperimenti è stato possibile discutere sulle capacità di autocorrezione del sistema, elemento chiave nello studio delle dinamiche della fiducia verso Wikipedia.