The VIMOS-VLT Deep Survey: the evolution of type-1 AGN

Quasars and AGN play an important role in many aspects of the modern cosmology. Of particular interest is the issue of the interplay between AGN activity and formation and evolution of galaxies and structures. Studies on nearby galaxies revealed that most (and possibly all) galaxy nuclei contain a super-massive black hole (SMBH) and that between a third and half of them are showing some evidence of activity (Kormendy and Richstone, 1995). The discovery of a tight relation between black holes mass and velocity dispersion of their host galaxy suggests that the evolution of the growth of SMBH and their host galaxy are linked together. In this context, studying the evolution of AGN, through the luminosity function (LF), is fundamental to constrain the theories of galaxy and SMBH formation and evolution. Recently, many theories have been developed to describe physical processes possibly responsible of a common formation scenario for galaxies and their central black hole (Volonteri et al., 2003; Springel et al., 2005a; Vittorini et al., 2005; Hopkins et al., 2006a) and an increasing number of observations in different bands are focused on collecting larger and larger quasar samples. Many issues remain however not yet fully understood. In the context of the VVDS (VIMOS-VLT Deep Survey), we collected and studied an unbiased sample of spectroscopically selected faint type-1 AGN with a unique and straightforward selection function. Indeed, the VVDS is a large, purely magnitude limited spectroscopic survey of faint objects, free of any morphological and/or color preselection. We studied the statistical properties of this sample and its evolution up to redshift z 4. Because of the contamination of the AGN light by their host galaxies at the faint magnitudes explored by our sample, we observed that a significant fraction of AGN in our sample would be missed by the UV excess and morphological criteria usually adopted for the pre-selection of optical QSO candidates. If not properly taken into account, this failure in selecting particular sub-classes of AGN could, in principle, affect some of the conclusions drawn from samples of AGN based on these selection criteria. The absence of any pre-selection in the VVDS leads us to have a very complete sample of AGN, including also objects with unusual colors and continuum shape. The VVDS AGN sample shows in fact redder colors than those expected by comparing it, for example, with the color track derived from the SDSS composite spectrum. In particular, the faintest objects have on average redder colors than the brightest ones. This can be attributed to both a large fraction of dust-reddened objects and a significant contamination from the host galaxy. We have tested these possibilities by examining the global spectral energy distribution of each object using, in addition to the U, B, V, R and I-band magnitudes, also the UV-Galex and the IR-Spitzer bands, and fitting it with a combination of AGN and galaxy emission, allowing also for the possibility of extinction of the AGN flux. We found that for 44% of our objects the contamination from the host galaxy is not negligible and this fraction decreases to 21% if we restrict the analysis to a bright subsample (M1450 <-22.15). Our estimated integral surface density at IAB < 24.0 is 500 AGN per square degree, which represents the highest surface density of a spectroscopically confirmed sample of optically selected AGN. We derived the luminosity function in B-band for 1.0 < z < 3.6 using the 1/Vmax estimator. Our data, more than one magnitude fainter than previous optical surveys, allow us to constrain the faint part of the luminosity function up to high redshift. A comparison of our data with the 2dF sample at low redshift (1 < z < 2.1) shows that the VDDS data can not be well fitted with the pure luminosity evolution (PLE) models derived by previous optically selected samples. Qualitatively, this appears to be due to the fact that our data suggest the presence of an excess of faint objects at low redshift (1.0 < z < 1.5) with respect to these models. By combining our faint VVDS sample with the large sample of bright AGN extracted from the SDSS DR3 (Richards et al., 2006b) and testing a number of different evolutionary models, we find that the model which better represents the combined luminosity functions, over a wide range of redshift and luminosity, is a luminosity dependent density evolution (LDDE) model, similar to those derived from the major Xsurveys. Such a parameterization allows the redshift of the AGN density peak to change as a function of luminosity, thus fitting the excess of faint AGN that we find at 1.0 < z < 1.5. On the basis of this model we find, for the first time from the analysis of optically selected samples, that the peak of the AGN space density shifts significantly towards lower redshift going to lower luminosity objects. The position of this peak moves from z 2.0 for MB <-26.0 to z 0.65 for -22< MB <-20. This result, already found in a number of X-ray selected samples of AGN, is consistent with a scenario of “AGN cosmic downsizing”, in which the density of more luminous AGN, possibly associated to more massive black holes, peaks earlier in the history of the Universe (i.e. at higher redshift), than that of low luminosity ones, which reaches its maximum later (i.e. at lower redshift). This behavior has since long been claimed to be present in elliptical galaxies and it is not easy to reproduce it in the hierarchical cosmogonic scenario, where more massive Dark Matter Halos (DMH) form on average later by merging of less massive halos.

Role of SP-A gene polymorphism in lung transplantation

Lung transplantation is a widely accepted therapeutic option for end stage lung disease. Clinical outcome is yet challenged by primary graft failure responsible for the majority of the early mortality, by chronic allograft dysfunction and chronic rejection accounting for more than 30% of deaths after the third postoperative year. Pulmonary surfactant proteins (SP) A, B, C and D are one of the first host defense mechanisms the lung can mount. SP-A in particular, produced by the type II pneumocytes, is active in the innate and adaptive immune system being an opsonin, but also regulating the macrophage and lymphocyte response. The main hypothesis for this project is that pulmonary surfactant protein A polymorphism may determine the early and long term lung allograft survival. Of note SP-A biologic activity seems to be genetically determined and SP-A polymorphisms have been associated to various lung disease. The two SP-A genes SP-A1 and SP-A2 have several polymorphisms within the coding region, SP-A1 (6A, 6A2-20), and SP-A2(1A, 1A0-13). The SP-A gene expression is regulated by cAMP, TTF-1 and glucocorticoids. In vitro studies have indicated that SP-A1 and SP-A2 gene variants may have a variable response to glucocorticoids. We proposed to determine if SP-A gene polymorphism predicts primary graft dysfunction and/or chronic lung allograft dysfunction and if SP-A may serve as a biomarker of lung allograft dysfunction. We also proposed to study the interaction between immunosuppressive drugs and SP-A expression and determine whether this is dependent on SP-A polymorphisms. This study will generate novel information improving our understanding of lung allograft dysfunction. It is conceivable that the information will stimulate the interest for a multi centre study to investigate if SP-A polymorphism may be integrated in the donor lung selection criteria and/or to implement post transplant tailored immunosuppression.

Psychobiological correlates of allostatic load

Introduction: The term Clinimetric was introduced by Feinstein in 1982, who first noticed that despite all the improvements in the assessment methods, a number of clinical phenomena were still unconsidered during the evaluation process. Yet today clinical phenomena, such as stress, relevant in diseases progression and course, are not completely evaluated. Only recently, according to the clinimetric approach, Fava and colleagues have introduced specific criteria for evaluating the allostatic overload in clinical setting. Methods: Participants were 240 blood donors recruited from May 2007 to December 2009 in 4 different blood Centers (AVIS) in Italy. Blood samples from each participant were collected for laboratory test the same day the self-rating instruments were administered (Psychosocial Index, Symptom Questionnaire, Psychological well-being scales, Temperament and Character inventory, Self-Report Altruism scale). The study explore different aspects describing sample characteristics and correlates of stress in the total sample (part I), new selection criteria applied to existing instruments to identify individuals reporting allostatic load (part II), and differences on biological correlates between subjects with vs without AL. Results: Significant differences according to gender and past illnesses have been found in different dimensions of well-being and distress. Further, distress was explained for more than 60% by 4 main factors such as anxiety, somatic symptoms, environmental mastery and persistence. According to the new criteria, 98 donors reported AL. Allostatic load individuals reported to engage in less altruistic behaviours. Also they differ in personality traits and characters from controls. In the last part, results showed significant differences among donors according to allostatic load on diverse biological parameters (RBC, MCV, immune essay). Conclusion: This study presents obvious limitations due to its preliminary nature. Further research are need to confirm that these new criteria may lead to identify high risk individuals reporting not only stressful situations but also vulnerabilities.

International cooperation in endourology: percutaneous and flexible ureteroscopic treatment of lower pole kidney stones

Introduction Lower pole kidney stones represent at time a challenge for the urologist. The gold standard treatment for intrarenal stones <2 cm is Extracorporeal Shock Wave Lithotripsy (ESWL) while for those >2 cm is Percutaneous Nephrolithotomy (PCNL). The success rate of ESWL, however, decreases when it is employed for lower pole stones, and this is particularly true in the presence of narrow calices or acute infundibular angles. Studies have proved that ureteroscopy (URS) is an efficacious alternative to ESWL for lower pole stones <2 cm, but this is not reflected by either the European or the American guidelines. The aim of this study is to present the results of a large series of flexible ureteroscopies and PCNLs for lower pole kidney stones from high-volume centers, in order to provide more evidences on the potential indications of the flexible ureteroscopy for the treatment of kidney stones. Materials and Methods A database was created and the participating centres retrospectively entered their data relating to the percutaneous and flexible ureteroscopic management of lower pole kidney stones. Patients included were treated between January 2005 and January 2010. Variables analyzed included case load number, preoperative and postoperative imaging, stone burden, anaesthesia (general vs. spinal), type of lithotripter, access location and size, access dilation type, ureteral access sheath use, visual clarity, operative time, stone-free rate, complication rate, hospital stay, analgesic requirement and follow-up time. Stone-free rate was defined as absence of residual fragments or presence of a single fragment <2 mm in size at follow-up imaging. Primary end-point was to test the efficacy and safety of flexible URS for the treatment of lower pole stones; the same descriptive analysis was conducted for the PCNL approach, as considered the gold standard for the treatment of lower pole kidney stones. In this setting, no statistical analysis was conducted owing to the different selection criteria of the patients. Secondary end-point consisted in matching the results of stone-free rates, operative time and complications rate of flexible URS and PCNL in the subgroup of patients harbouring lower pole kidney stones between 1 and 2 cm in the higher diameter. Results A total 246 patients met the criteria for inclusion. There were 117 PCNLs (group 1) and 129 flexible URS (group 2). Ninety-six percent of cases were diagnosed by CT KUB scan. Mean stone burden was 175±160 and 50±62 mm2 for groups 1 and 2, respectively. General anaesthesia was induced in 100 % and 80% of groups 1 and 2, respectively. Pneumo-ultrasonic energy was used in 84% of cases in the PCNL group, and holmium laser in 95% of the cases in the flexible URS group. The mean operative time was 76.9±44 and 63±37 minutes for groups 1 and 2 respectively. There were 12 major complications (11%) in group 1 (mainly Grade II complications according to Clavidien classification) and no major complications in group 2. Mean hospital stay was 5.7 and 2.6 days for groups 1 and 2, respectively. Ninety-five percent of group 1 and 52% of group 2 required analgesia for a period longer than 24 hours. Intraoperative stone-free rate after a single treatment was 88.9% for group 1 and 79.1% for group 2. Overall, 6% of group 1 and 14.7% of group 2 required a second look procedure. At 3 months, stone-free rates were 90.6% and 92.2% for groups 1 and 2, respectively, as documented by follow-up CT KUB (22%) or combination of intra-venous pyelogram, regular KUB and/or kidney ultrasound (78%). In the subanalysis conducted comparing 82 vs 65 patients who underwent PCNL and flexible URS for lower pole stones between 1 and 2 cm, intreoperative stone-free rates were 88% vs 68% (p= 0.03), respectively; anyway, after an auxiliary procedure which was necessary in 6% of the cases in group 1 and 23% in group 2 (p=0.03), stone-free rates at 3 months were not statistically significant (91.5% vs 89.2%; p=0.6). Conversely, the patients undergoing PCNL maintained a higher risk of complications during the procedure, with 9 cases observed in this group versus 0 in the group of patients treated with URS (p=0.01) Conclusions These data highlight the value of flexible URS as a very effective and safe option for the treatment of kidney stones; thanks to the latest generation of flexible devices, this new technical approach seems to be a valid alternative in particular for the treatment of lower pole kidney stones less than 2 cm. In high-volume centres and in the hands of skilled surgeons, this technique can approach the stone-free rates achievable through PCNL in lower pole stones between 1 and 2 cm, with a very low risk of complications. Furthermore, the results confirm the high success rate and relatively low morbidity of modern PCNL for lower pole stones, with no difference detectable between the prone and supine position.

Wide-scale population genomics of Atlantic bluefin tuna (Thunnus thynnus) inferred by novel high-throughput technology

My PhD project was focused on Atlantic bluefin tuna, Thunnus thynnus, a fishery resource overexploited in the last decades. For a better management of stocks, it was necessary to improve scientific knowledge of this species and to develop novel tools to avoid collapse of this important commercial resource. To do this, we used new high throughput sequencing technologies, as Next Generation Sequencing (NGS), and markers linked to expressed genes, as SNPs (Single Nucleotide Polymorphisms). In this work we applied a combined approach: transcriptomic resources were used to build cDNA libreries from mRNA isolated by muscle, and genomic resources allowed to create a reference backbone for this species lacking of reference genome. All cDNA reads, obtained from mRNA, were mapped against this genome and, employing several bioinformatics tools and different restricted parameters, we achieved a set of contigs to detect SNPs. Once a final panel of 384 SNPs was developed, following the selection criteria, it was genotyped in 960 individuals of Atlantic bluefin tuna, including all size/age classes, from larvae to adults, collected from the entire range of the species. The analysis of obtained data was aimed to evaluate the genetic diversity and the population structure of Thunnus thynnus. We detect a low but significant signal of genetic differentiation among spawning samples, that can suggest the presence of three genetically separate reproduction areas. The adult samples resulted instead genetically undifferentiated between them and from the spawning populations, indicating a presence of panmictic population of adult bluefin tuna in the Mediterranean Sea, without different meta populations.

Sviluppo di tecniche per la progettazione delle reti di monitoraggio della qualita' dell'aria

L’obiettivo del lavoro consiste nell’implementare una metodologia operativa volta alla progettazione di reti di monitoraggio e di campagne di misura della qualità dell’aria con l’utilizzo del laboratorio mobile, ottimizzando le posizioni dei dispositivi di campionamento rispetto a differenti obiettivi e criteri di scelta. La revisione e l’analisi degli approcci e delle indicazioni fornite dalla normativa di riferimento e dai diversi autori di lavori scientifici ha permesso di proporre un approccio metodologico costituito da due fasi operative principali, che è stato applicato ad un caso studio rappresentato dal territorio della provincia di Ravenna. La metodologia implementata prevede l’integrazione di numerosi strumenti di supporto alla valutazione dello stato di qualità dell’aria e degli effetti che gli inquinanti atmosferici possono generare su specifici recettori sensibili (popolazione residente, vegetazione, beni materiali). In particolare, la metodologia integra approcci di disaggregazione degli inventari delle emissioni attraverso l’utilizzo di variabili proxy, strumenti modellistici per la simulazione della dispersione degli inquinanti in atmosfera ed algoritmi di allocazione degli strumenti di monitoraggio attraverso la massimizzazione (o minimizzazione) di specifiche funzioni obiettivo. La procedura di allocazione sviluppata è stata automatizzata attraverso lo sviluppo di un software che, mediante un’interfaccia grafica di interrogazione, consente di identificare delle aree ottimali per realizzare le diverse campagne di monitoraggio