Self-consistent model for ambipolar tunneling in quantum-well systems

We present a self-consistent approach to describe ambipolar tunneling in asymmetrical double quantum wells under steady-state excitation and extend the results to the case of tunneling from a near-surface quantum well to surface states. The results of the model compare very well with the behavior observed in photoluminescence experiments in $InGaAs/InP$ asymmetric double quantum wells and in near-surface $AlGaAs/GaAs$ single quantum wells.Comment: 10 pages, REVTeX 3.

Lean towards learning: connecting Lean Thinking and human resource management in UK higher education

From its origins in the automotive industry, Lean Thinking is increasingly being seen as a solution to problems of efficiency and quality in other industries and sectors. In recent years attempts have been made to transfer Lean principles and practice to the higher education sector with indications of mixed consequences and debate over its suitability. This paper contributes to the debate by drawing evidence from thirty-four interviews conducted across two UK universities that have implemented Lean in some of their activities and we pay particular attention to the role of the HR function in facilitating its introduction. The findings suggest there are problems in understanding, communicating and transferring Lean Thinking in the higher education context; that, despite HR systems being vital facets of Lean, HR professionals are excluded from participation; and that as a consequence the depth and breadth of Lean application in the two institutions is very limited

Evaluation of neutron induced reaction cross sections in the resolved and unresolved resonance region at EC-JRC-IRMM

Recent efforts made at the EC-JRC-IRMM to produce evaluated cross section data files for neutron induced reactions are described as well as the methodology applied in both the resolved and unresolved resonance. For the resolved resonance region the paper focuses on a recent evaluation of isotopes present in natural cadmium. For the unresolved resonance region results for gold are presented.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Germano Sartelli

Libro-catalogo della mostra sugli artisti imolesi che hanno partecipato alle Biennali Internazionali d'arte di Venezia. Capitolo dedicato all'opera dello scultore Germano Sartelli, tra i principali esponenti dell'informale italiano

Risk factors for pre-clinical atherosclerosis in adolescents with type 1 diabetes

Aims: To assess whether, besides "traditional" risk factors, overall oxidative stress, oxidized lipoproteins, and glycemic variability are associated with early macro-vascular damage in type 1 diabetes (T1D). Methods: In 267 children/adolescents with T1D (130 girls, age 9.1-23.0 years) we evaluated: derivatives of reactive oxygen metabolites [d-ROMs], serum total antioxidant capacity [TAC] and oxidized LDL-cholesterol [oxLDL]; markers of early vascular damage (Lipoprotein-associated phospholipase A2 [Lp-PLA2], z-score of carotid intima-media thickness [z-cIMT] and carotid-femoral pulse wave velocity [z-PWV]); CGM metrics of four weeks preceding the visit, central systolic/diastolic blood pressures (cSBP/cDBP), and HbA1c, z-score of BP (z-SBP/z-DBP) and circulating lipids longitudinally collected since T1D onset.. Three general linear models were built with z-cIMT, z-PWV adjusted for current cDBP, and Lp-PLA2 as independent variables. Results: The z-cIMT was associated with male gender (B = 0.491, η2 = 0.029, p = 0.005), cSBP (B = 0.023, η2 = 0.026, p = 0.008) and oxLDL (B = 0.022, η2 = 0.022, p = 0.014). The z-PWV was associated with diabetes duration (B = 0.054, η2 = 0.024, p = 0.016), daily insulin dose (B = 0.52, η2 = 0.018, p = 0.045), longitudinal z-SBP (B = 0.18, η2 = 0.018, p = 0.045) and dROMs (B = 0.003, η2 = 0.037, p = 0.004). Lp-PLA2 was associated with age (B = 0.221, η2 = 0.079, p = 3*10-6), oxLDL (B = 0.081, η2 = 0.050, p = 2*10-4), longitudinal LDL-cholesterol (B = 0.031, η2 = 0.043, p = 0.001) and male gender (B = -1.62, η2 = 0.10, p = 1.3*107). Conclusions: Oxidative stress, male gender, insulin dose, diabetes duration and longitudinal lipids and blood pressure, contributed to the variance of early vascular damage in young patients with T1D

Role and regulation of ACC deaminase gene in Sinorhizobium meliloti: Is it a symbiotic, rhizospheric or endophytic gene?

Plant-associated bacteria exhibit a number of different strategies and specific genes allow bacteria to communicate and metabolically interact with plant tissues. Among the genes found in the genomes of plant-associated bacteria, the gene encoding the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase (acdS) is one of the most diffused. This gene is supposed to be involved in the cleaving of plant-produced ACC, the precursor of the plant stress-hormone ethylene toning down the plant response to infection. However, few reports are present on the actual role in rhizobia, one of the most investigated groups of plant-associated bacteria. In particular, still unclear is the origin and the role of acdS in symbiotic competitiveness and on the selective benefit it may confer to plant symbiotic rhizobia. Here we present a phylogenetic and functional analysis of acdS orthologs in the rhizobium model-species Sinorhizobium meliloti. Results showed that acdS orthologs present in S. meliloti pangenome have polyphyletic origin and likely spread through horizontal gene transfer, mediated by mobile genetic elements. When acdS ortholog from AK83 strain was cloned and assayed in S. meliloti 1021 (lacking acdS), no modulation of plant ethylene levels was detected, as well as no increase in fitness for nodule occupancy was found in the acdS-derivative strain compared to the parental one. Surprisingly, AcdS was shown to confer the ability to utilize formamide and some dipeptides as sole nitrogen source. Finally, acdS was shown to be negatively regulated by a putative leucine-responsive regulator (LrpL) located upstream to acdS sequence (acdR). acdS expression was induced by root exudates of both legumes and non-leguminous plants. We conclude that acdS in S. meliloti is not directly related to symbiotic interaction, but it could likely be involved in the rhizospheric colonization or in the endophytic behavior

Enhancement of lysosomal glycohydrolase activity in human primary B lymphocytes during spontaneous apoptosis.

It has been shown that lysosomes are involved in B cell apoptosis but lysosomal glycohydrolases have never been investigated during this event. In this study we determined the enzymatic activities of some lysosomal glycohydrolases in human tonsil B lymphocytes (TBL) undergoing in vitro spontaneous apoptosis. Fluorimetric methods were used to evaluate the activities of β-hexosaminidases, α-mannosidase, β-mannosidase, β-galactosidase, β-glucuronidase and α-fucosidase. Results show that in TBL during spontaneous apoptosis, there is a significant increase in the activity of β-hexosaminidases, α-mannosidase, β-mannosidase and β-galactosidase. Also β-glucuronidase and α-fucosidase activities increase but not in a significant manner. Further studies on β-hexosaminidases revealed that also mRNA expression of the α- and β-subunits, which constitute these enzymes, increases during spontaneous TBL apoptosis. When TBL are protected from apoptosis by the thiol molecule N-acetyl-L-cysteine (NAC), there is no longer any increase in glycohydrolase activities and mRNA expression of β-hexosaminidase α- and β-subunits. This study demonstrates for the first time that the activities and expression of some lysosomal glycohydrolases are enhanced in TBL during spontaneous apoptosis and that these increases are prevented when TBL apoptosis is inhibited

Il riequilibrio della finanza pubblica negli anni Novanta

Gli anni novanta sono caratterizzati dal riequilibrio della finanza pubblica: l’indebitamento netto delle Amministrazioni pubbliche che nel 1990 era pari all’11,8 per cento del PIL scende nel 1999 all’1,8 per cento. Gli anni ottanta possono essere giudicati ex post un periodo nel quale è tardato il riconoscimento della necessità del rigore fiscale, con un indebitamento netto mediamente pari al 10,8 del PIL e pressoché costante nel periodo. Questa caratterizzazione valevole per l’intero decennio, può essere meglio precisata. Ad esempio, l’anno 1991 (e non solo il 1990) può essere collegato a quelli del quinquennio precedente, che è stato definito, giustamente, come quello del “risanamento mancato” ; il 1992 è l’anno della “svolta” ; il 1997 l’anno in cui il riequilibrio, con gran prontezza, è stato colto con “astuzia e virtù”. Tuttavia, secondo gli autori di questa nota, sarebbe erronea una suddivisione del decennio in alcuni episodi di manovre di finanza pubblica, ora fallite ora riuscite, come alcune volte sono stati presentati nella letteratura; il processo di riequilibrio è stato un percorso continuo, ancor più di quanto appaia nei dati grezzi dell’indebitamento netto e dell’avanzo primario, sia nella programmazione e nella attuazione delle manovre fiscali, sia per la continuità dei risultati. Ovviamente alcuni momenti del processo sono stati molto qualificanti, e saranno posti in rilievo nell’analisi. Il successo della politica fiscale perseguita nel decennio, non esime comunque dal porsi e risolvere ulteriori problemi, derivanti nel medio periodo dalle pressioni demografiche, da possibili riforme istituzionali e dall’intensificarsi della competitività tra i vari sistemi - paese

Impact of CFTR Modulators on Beta-Cell Function in Children and Young Adults with Cystic Fibrosis

Background: To date, no consistent data are available on the possible impact of CFTR modulators on glucose metabolism. The aim of this study was to test the hypothesis that treatment with CFTR modulators is associated with an improvement in the key direct determinants of glucose regulation in children and young adults affected by Cystic Fibrosis (CF). Methods: In this study, 21 CF patients aged 10–25 underwent oral glucose tolerance test (OGTT) before and after 12–18 months of treatment with Lumacaftor/Ivacaftor or Elexacaftor-Ivacaftor-Tezacaftor. β-cell function (i.e., first and second phase of insulin secretion measured as derivative and proportional control, respectively) and insulin clearance were estimated by OGTT mathematical modelling. Insulin sensitivity was estimated by the Oral Glucose Sensitivity Index (OGIS). The dynamic interplay between β-cell function, insulin clearance and insulin sensitivity was analysed by vector plots of glucose-stimulated insulin bioavailability vs. insulin sensitivity. Results: No changes in glucose tolerance occurred after either treatment, whereas a significant improvement in pulmonary function and chronic bacterial infection was observed. Beta cell function and insulin clearance did not change in both treatment groups. Insulin sensitivity worsened in the Lumacaftor/Ivacaftor group. The analysis of vector plots confirmed that glucose regulation was stable in both groups. Conclusions: Treatment of CF patients with CFTR modulators does not significantly ameliorate glucose homeostasis and/or any of its direct determinants