Caratteristiche e provenienza dei marmi

I frammenti lapidei considerati nel presente contributo sono stati in buona parte rinvenuti accatastati a poca distanza dai resti di fornaci (calcare) funzionali alla trasformazione delle pietre in calce. Si pu\uf2 ipotizzare che gli elementi recuperati fossero destinati alla calcinazione anche perch\ue9 costituiti esclusivamente da litotipi calcarei (marmi bianchi e colorati, calcari, arenarie calcaree). Assenti, invece, sono risultate essere le pietre non calcaree e comunemente utilizzate in et\ue0 romana come graniti, porfidi, andesiti o marmi dolomitici, non idonee alla produzione di calce

The response of the male freshwater goby to natural and synthetic male courtship sound playback following exposure to different female sexual sitimuli.

Among teleosts, field and laboratory experiments have shown the playback of male courtship sounds often elicits competitive courtship and sound emission in the territorial male. However, the importance of female stimulation for the male response to the sound is poorly understood. In this study, playback experiments with the freshwater goby, Padogobius martensii, examined the response of resident males (i.e. males individually housed within laboratory tanks for at least 5 days) to natural and synthetic male courtship sounds after exposure to chemical or visual stimuli from a ripe female. All playback tests consisted of one experimental (sound playback) and two control treatments, all of equal duration. Three experiments were conducted on a first group of 12 males using natural courtship sounds. Experiment 1 consisted of playing back the sound to a male that had not exposed to female stimulation for at least 24 hr. The same male was exposed to the “female pheromone” by dropping a few cm3 of female holding water into the male’s tank, just prior to playback (Experiment 2), or to the view of a live ripe female in a close-by tank, during playback (Experiment 3). The sound playback failed to elicit positive responses by males not exposed to female stimuli (Experiment 1), and did not increase courtship activity of the male in visual contact with the female (Experiment 3). However, it increased swimming activity and facilitated courtship and sound production in the male after an increase in sexual arousal by prior chemical stimulation (Experiment 2). In Experiment 4, the synthetic version of the courtship sound and one deprived of pulse-rate modulation and harmonic content (pure tone) were played back to 10 resident males following prior chemical stimulation. The synthetic courtship sound, but not the pure tone, was effective in eliciting positive responses by the sexually aroused male. Functional implications of the responses to the courtship sound for the territorial male are discussed. The results are relevant to the understanding of the role of sound communication and interception among gobies and to develop playback experiments in the field

Free-carrier screening of polarization fields in wurtzite GaN/InGaN laser structures

The free-carrier screening of macroscopic polarization fields in wurtzite GaN/InGaN quantum wells lasers is investigated via a self-consistent tight-binding approach. We show that the high carrier concentrations found experimentally in nitride laser structures effectively screen the built-in spontaneous and piezoelectric polarization fields, thus inducing a ``field-free'' band profile. Our results explain some heretofore puzzling experimental data on nitride lasers, such as the unusually high lasing excitation thresholds and emission blue-shifts for increasing excitation levels.Comment: RevTeX 4 pages, 4 figure

Characterization of CDKN2A(p16) methylation and impact in colorectal cancer: systematic analysis using pyrosequencing

Background The aim of this study is to analyse CDKN2A methylation using pyrosequencing on a large cohort of colorectal cancers and corresponding non-neoplastic tissues. In a second step, the effect of methylation on clinical outcome is addressed. Methods Primary colorectal cancers and matched non-neoplastic tissues from 432 patients underwent CDKN2A methylation analysis by pyrosequencing (PyroMarkQ96). Methylation was then related to clinical outcome, microsatellite instability (MSI), and BRAF and KRAS mutation. Different amplification conditions (35 to 50 PCR cycles) using a range of 0-100% methylated DNA were tested. Results Background methylation was at most 10% with ≥35 PCR cycles. Correlation of observed and expected values was high, even at low methylation levels (0.02%, 0.6%, 2%). Accuracy of detection was optimal with 45 PCR cycles. Methylation in normal mucosa ranged from 0 to >90% in some cases. Based on the maximum value of 10% background, positivity was defined as a ≥20% difference in methylation between tumor and normal tissue, which occurred in 87 cases. CDKN2A methylation positivity was associated with MSI (p = 0.025), BRAF mutation (p < 0.0001), higher tumor grade (p < 0.0001), mucinous histology (p = 0.0209) but not with KRAS mutation. CDKN2A methylation had an independent adverse effect (p = 0.0058) on prognosis. Conclusion The non-negligible CDKN2A methylation of normal colorectal mucosa may confound the assessment of tumor-specific hypermethylation, suggesting that corresponding non-neoplastic tissue should be used as a control. CDKN2A methylation is robustly detected by pyrosequencing, even at low levels, suggesting that this unfavorable prognostic biomarker warrants investigation in prospective studies

Rare KIT (CD117) expression in multiple myeloma abrogates the usefulness of imatinib mesylate treatment

Background: Imatinib mesylate blocks the tyrosine kinase activity of KIT (CD117) and is an effective treatment for gastrointestinal stromal tumors. In multiple myeloma, KIT expression has been detected by flow cytometry in about 33% of specimens, but no previous immunohistochemical assessment has yet been made of the expression pattern of KIT. Materials and methods: We performed immunohistochemical analyses of 100 patients, including 72 with multiple myeloma (MM), 8 with lymphoplasmacytic lymphoma (LPL), 10 with monoclonal gammopathy of undetermined significance (MGUS) and 10 with reactive plasmocytosis. One KIT-positive MM was sequenced using polymerase chain reaction analysis. Results: In MM, only 2 cases (2.8%) were KIT positive. The great majority of the cases (97, 2%) did not express the KIT receptor tyrosine kinase. No mutation of the c-kit gene was detected. Conclusions: KIT expression is a rare event in MM and not detectable in MGUS and LPL. Therefore, treatment with imatinib is unlikely to be effective in these patient

Cellular Automaton Study of Time-Dynamics of Avalanche Breakdown in IMPATT Diodes

Employing a recently developed efficient cellular automaton technique for solving Boltzmann's transport equation for realistic devices, we present a detailed study of the carrier dynamics in GaAs avalanche p-i-n (IMPATT) diodes. We find that the impact ionization in reverse bias p-i-n diodes with ultrathin (less than 50 nm) intrinsic regions is triggered by Zener tunneling rather than by thermal generation. The impact generation of hot carriers occurs mainly in the low-field junction regions rather than in the high field intrinsic zone. The calculations predict significantly more minority carriers on the n-side than on the p-side

Reperti lapidei di et\ue0 romana rinvenuti a Fornovo Taro: provenienza e circolazione

Nelle collezioni del Museo Archeologico Nazionale di Parma tra i reperti litici di et\ue0 romana figurano anche tre oggetti recuperati a Fornovo Taro o nelle sue adiacenze diversi per contesto di ritrovamento e destinazione d\u2019uso, di cui si \ue8 analizzata la pietra ai fini di determinarne la provenienza e le possibili rotte commerciali. In particolare sono stati presi in esame:- una epigrafe frammentaria (n.inv. L 49), databile al II secolo d.C., gi\ue0 murata in uno dei pilastri della Pieve ed entrata a far parte delle collezioni museali nel 18671; - una piccola scultura raffigurante Afrodite accovacciata secondo il modello dello scultore ellenistico Doidalsas (n.inv. MANPr 31963), recuperata negli anni Ottanta del secolo scorso al margine occidentale di Piazza IV Novembre, databile ai primi decenni sempre del II secolo d.C.2; - una base di colonna (mancante di n.inv. e abbreviata con la sigla BCG), recuperata nel 1980 a Roncolungo di Sivizzano tra i materiali accatastati ai margini della strada statale dal proprietario del terreno in attesa di disfarsene

Complete Genome Sequence of Bifidobacterium longum W11 (LMG P-21586), Used as a Probiotic Strain

We report the complete genome sequence of Bifidobacterium longum W11 (LMG P-21586) isolated from the intestinal microbiota of a healthy man. The analysis of the sequence may provide insights into the microbiological characteristics and the functional activity of this probiotic strain