Showing papers by "University of Bologna published in 2005"

Handbook of Fingerprint Recognition

Abstract: A major new professional reference work on fingerprint security systems and technology from leading international researchers in the field Handbook provides authoritative and comprehensive coverage of all major topics, concepts, and methods for fingerprint security systems This unique reference work is an absolutely essential resource for all biometric security professionals, researchers, and systems administrators

Market Size, Trade, and Productivity

Abstract: We develop a monopolistically competitive model of trade with firm heterogeneity—in terms of productivity differences—and endogenous differences in the "toughness" of competition across markets—in terms of the number and average productivity of competing firms. We analyse how these features vary across markets of different size that are not perfectly integrated through trade; we then study the effects of different trade liberalization policies. In our model, market size and trade affect the toughness of competition, which then feeds back into the selection of heterogeneous producers and exporters in that market. Aggregate productivity and average mark-ups thus respond to both the size of a market and the extent of its integration through trade (larger, more integrated markets exhibit higher productivity and lower mark-ups). Our model remains highly tractable, even when extended to a general framework with multiple asymmetric countries integrated to different extents through asymmetric trade costs. We believe this provides a useful modelling framework that is particularly well suited to the analysis of trade and regional integration policy scenarios in an environment with heterogeneous firms and endogenous mark-ups.

Sildenafil citrate therapy for pulmonary arterial hypertension.

Abstract: background Sildenafil inhibits phosphodiesterase type 5, an enzyme that metabolizes cyclic guanosine monophosphate, thereby enhancing the cyclic guanosine monophosphate– mediated relaxation and growth inhibition of vascular smooth-muscle cells, including those in the lung. methods In this double-blind, placebo-controlled study, we randomly assigned 278 patients with symptomatic pulmonary arterial hypertension (either idiopathic or associated with connective-tissue disease or with repaired congenital systemic-to-pulmonary shunts) to placebo or sildenafil (20, 40, or 80 mg) orally three times daily for 12 weeks. The primary end point was the change from baseline to week 12 in the distance walked in six minutes. The change in mean pulmonary-artery pressure and World Health Organization (WHO) functional class and the incidence of clinical worsening were also assessed, but the study was not powered to assess mortality. Patients completing the 12-week randomized study could enter a long-term extension study. results The distance walked in six minutes increased from baseline in all sildenafil groups; the mean placebo-corrected treatment effects were 45 m (+13.0 percent), 46 m (+13.3 percent), and 50 m (+14.7 percent) for 20, 40, and 80 mg of sildenafil, respectively (P<0.001 for all comparisons). All sildenafil doses reduced the mean pulmonary-artery pressure (P = 0.04, P = 0.01, and P<0.001, respectively), improved the WHO functional class (P = 0.003, P<0.001, and P<0.001, respectively), and were associated with side effects such as flushing, dyspepsia, and diarrhea. The incidence of clinical worsening did not differ significantly between the patients treated with sildenafil and those treated with placebo. Among the 222 patients completing one year of treatment with sildenafil monotherapy, the improvement from baseline at one year in the distance walked in six minutes was 51 m. conclusions Sildenafil improves exercise capacity, WHO functional class, and hemodynamics in patients with symptomatic pulmonary arterial hypertension.

I-Mutant2.0: predicting stability changes upon mutation from the protein sequence or structure.

Abstract: I-Mutant2.0 is a support vector machine (SVM)-based tool for the automatic prediction of protein stability changes upon single point mutations. I-Mutant2.0 predictions are performed starting either from the protein structure or, more importantly, from the protein sequence. This latter task, to the best of our knowledge, is exploited for the first time. The method was trained and tested on a data set derived from ProTherm, which is presently the most comprehensive available database of thermodynamic experimental data of free energy changes of protein stability upon mutation under different conditions. I-Mutant2.0 can be used both as a classifier for predicting the sign of the protein stability change upon mutation and as a regression estimator for predicting the related ΔΔG values. Acting as a classifier, I-Mutant2.0 correctly predicts (with a cross-validation procedure) 80% or 77% of the data set, depending on the usage of structural or sequence information, respectively. When predicting ΔΔG values associated with mutations, the correlation of predicted with expected/experimental values is 0.71 (with a standard error of 1.30 kcal/mol) and 0.62 (with a standard error of 1.45 kcal/mol) when structural or sequence information are respectively adopted. Our web interface allows the selection of a predictive mode that depends on the availability of the protein structure and/or sequence. In this latter case, the web server requires only pasting of a protein sequence in a raw format. We therefore introduce I-Mutant2.0 as a unique and valuable helper for protein design, even when the protein structure is not yet known with atomic resolution. Availability: http://gpcr.biocomp.unibo.it/cgi/predictors/I-Mutant2.0/I-Mutant2.0.cgi.

Systematically convergent basis sets for transition metals. II. Pseudopotential-based correlation consistent basis sets for the group 11 (Cu, Ag, Au) and 12 (Zn, Cd, Hg) elements

Abstract: Sequences of basis sets that systematically converge towards the complete basis set (CBS) limit have been developed for the coinage metals (Cu, Ag, Au) and group 12 elements (Zn, Cd, Hg). These basis sets are based on recently published small-core relativistic pseudopotentials [Figgen D, Rauhut G, Dolg M, Stoll H (2005) Chem Phys 311:227] and range in size from double- through quintuple-ζ. Series of basis sets designed for valence-only and outer-core electron correlation are presented, as well as these sets augmented by additional diffuse functions for the accurate description of negative ions and weak interactions. Selected benchmark calculations at the coupled cluster level of theory are presented for both atomic and molecular properties. The latter include the calculation of both spectroscopic and thermochemical properties of the homonuclear dimers Cu2, Ag2, and Au2, as well as the van der Waals species Zn2, Cd2, and Hg2. The CBS limit results, including the effects of core-valence correlation and spin-orbit coupling, represent some of the most accurate carried out to date and result in new recommendations for the equilibrium bond lengths of the group 12 dimers. Comparisons are also made to a limited number of all-electron Douglas–Kroll–Hess (DKH) calculations (second and third order) carried out using new correlation consistent basis sets of triple-ζ quality.

BRAF mutation predicts a poorer clinical prognosis for papillary thyroid cancer

Abstract: Context: Use of BRAF mutation in papillary thyroid cancer (PTC) has the potential to improve risk stratification of this cancer. Objective: The objective of the study was to investigate the prognostic value of BRAF mutation in patients with PTC. Design, Setting, and Subjects: In a multicenter study of 219 PTC patients, data on their clinicopathological characteristics and clinical courses between 1990 and 2004 were retrospectively collected, and their tumor BRAF mutation status was determined. Associations of BRAF mutation with initial tumor characteristics and subsequent recurrence were analyzed. Main Outcome Measure: Relationships between the BRAF mutation status and clinicopathological outcomes, including recurrence, were measured. Results: We found a significant association between BRAF mutation and extrathyroidal invasion (P < 0.001), lymph node metastasis (P < 0.001), and advanced tumor stage III/IV (P = 0.007) at initial surgery. This association remained significant on multivariate analysis, adjus...

Gossip-based aggregation in large dynamic networks

Abstract: As computer networks increase in size, become more heterogeneous and span greater geographic distances, applications must be designed to cope with the very large scale, poor reliability, and often, with the extreme dynamism of the underlying network. Aggregation is a key functional building block for such applications: it refers to a set of functions that provide components of a distributed system access to global information including network size, average load, average uptime, location and description of hotspots, and so on. Local access to global information is often very useful, if not indispensable for building applications that are robust and adaptive. For example, in an industrial control application, some aggregate value reaching a threshold may trigger the execution of certain actions; a distributed storage system will want to know the total available free space; load-balancing protocols may benefit from knowing the target average load so as to minimize the load they transfer. We propose a gossip-based protocol for computing aggregate values over network components in a fully decentralized fashion. The class of aggregate functions we can compute is very broad and includes many useful special cases such as counting, averages, sums, products, and extremal values. The protocol is suitable for extremely large and highly dynamic systems due to its proactive structure---all nodes receive the aggregate value continuously, thus being able to track any changes in the system. The protocol is also extremely lightweight, making it suitable for many distributed applications including peer-to-peer and grid computing systems. We demonstrate the efficiency and robustness of our gossip-based protocol both theoretically and experimentally under a variety of scenarios including node and communication failures.

Biofilm in implant infections: its production and regulation.

Abstract: A significant proportion of medical implants become the focus of a device-related infection, difficult to eradicate because bacteria that cause these infections live in well-developed biofilms. Biofilm is a microbial derived sessile community characterized by cells that are irreversibly attached to a substratum or interface to each other, embedded in a matrix of extracellular polymeric substances that they have produced. Bacterial adherence and biofilm production proceed in two steps: first, an attachment to a surface and, second, a cell-to-cell adhesion, with pluristratification of bacteria onto the artificial surface. The first step requires the mediation of bacterial surface proteins, the cardinal of which is similar to S. aureus autolysin and is denominated AtlE. In staphylococci the matrix of extracellular polymeric substances of biofilm is a polymer of beta-1,6-linked N-acetylglucosamine (PIA), whose synthesis is mediated by the ica operon. Biofilm formation is partially controlled by quorum sensing, an interbacterial communication mechanism dependent on population density. The principal implants that can be compromised by biofilm associated infections are: central venous catheters, heart valves, ventricular assist devices, coronary stents, neurosurgical ventricular shunts, implantable neurological stimulators, arthro-prostheses, fracture-fixation devices, inflatable penile implants, breast implants, cochlear implants, intraocular lenses, dental implants. Biofilms play an important role in the spread of antibiotic resistance. Within the high dense bacterial population, efficient horizontal transfer of resistance and virulence genes takes place. In the future, treatments that inhibit the transcription of biofilm controlling genes might be a successful strategy in inhibiting these infections.A significant proportion of medical implants become the focus of a device-related infection, difficult to eradicate because bacteria that cause these infections live in well-developed biofilms. Biofilm is a microbial derived sessile community characterized by cells that are irreversibly attached to a substratum or interface to each other, embedded in a matrix of extracellular polymeric substances that they have produced. Bacterial adherence and biofilm production proceed in two steps: first, an attachment to a surface and, second, a cell-to-cell adhesion, with pluristratification of bacteria onto the artificial surface. The first step requires the mediation of bacterial surface proteins, the cardinal of which is similar to S. aureus autolysin and is denominated AtlE. In staphylococci the matrix of extracellular polymeric substances of biofilm is a polymer of beta-1,6-linked N-acetylglucosamine (PIA), whose synthesis is mediated by the ica operon. Biofilm formation is partially controlled by quorum sensing, an interbacterial communication mechanism dependent on population density. The principal implants that can be compromised by biofilm associated infections are: central venous catheters, heart valves, ventricular assist devices, coronary stents, neurosurgical ventricular shunts, implantable neurological stimulators, arthro-prostheses, fracture-fixation devices, inflatable penile implants, breast implants, cochlear implants, intra-ocular lenses, dental implants. Biofilms play an important role in the spread of antibiotic resistance. Within the high dense bacterial population, efficient horizontal transfer of resistance and virulence genes takes place. In the future, treatments that inhibit the transcription of biofilm controlling genes might be a successful strategy in inhibiting these infections.

The VIMOS VLT deep survey. First epoch VVDS-deep survey: 11 564 spectra with 17.5 ≤ IAB ≤ 24, and the redshift distribution over 0 ≤ z ≤ 5

Abstract: This paper presents the ``First Epoch\'\' sample from the VIMOS VLT Deep Survey (VVDS). The VVDS goals, observations, data reduction with VIPGI, and redshift measurement with KBRED are discussed. Data have been obtained with the VIsible Multi Object Spectrograph (VIMOS) on the ESO-VLT UT3, allowing to observe ~600 slits simultaneously at R~230. A total of 11564 objects have been observed in the VVDS-02h and VVDS-CDFS Deep fields over a total area of 0.61deg^2, selected solely on the basis of apparent magnitude 17.5 <=I_{AB} <=24. The VVDS covers the redshift range 0 < z <= 5. It is successfully going through the ``redshift desert\'\' 1.523.5, probing the bright star forming population of galaxies. This sample provides an unprecedented dataset to study galaxy evolution over 90% of the life of the universe

Stomatal, mesophyll conductance and biochemical limitations to photosynthesis as affected by drought and leaf ontogeny in ash and oak trees

Abstract: Gas exchange measurements were carried out on ash and oak trees in a forest plantation during three whole growing seasons characterized by different water availability (2001, 2002 and 2003). A quantitative limitation analysis was applied to estimate the effects of drought and leaf ontogeny on stomatal ( S L ) and non-stomatal limitations ( NS L ) to light-saturated net photosynthesis ( A max ), relative to the seasonal maximum rates obtained under conditions of optimal soil water content. Furthermore, based on combined gas exchange and chlorophyll fluorescence measurements, NS L was partitioned into a diffusive (due to a decrease in mesophyll conductance, MC L ) and a biochemical component (due to a decrease in carboxylation capacity, B L ). During the wettest year (2002), the seasonal pattern of both A max and stomatal conductance ( g sw ) was characterized in both species by a rapid increase during spring and a slight decline over the summer. However, with a moderate (year 2001) or a severe (year 2003) water stress, the summer decline of A max and g sw was more pronounced and increased with drought intensity (30‐40% in 2001, 60‐75% in 2003). The limitation analysis showed that during the spring and the autumn periods S L , MC L and B L were of similar magnitude. By contrast, from the summer data it emerged that all the limitations increased with drought intensity, but their relative contribution changed. At mild to moderate water stress (corresponding to values of g sw > 100 mmol H 2 O m

Survival with first-line bosentan in patients with primary pulmonary hypertension

Abstract: Primary pulmonary hypertension (PPH) is a progressive disease with high mortality. Administration of i.v. epoprostenol has demonstrated improved exercise tolerance, haemodynamics, and survival. The orally active, dual endothelin receptor antagonist bosentan improves exercise endurance, haemodynamics, and functional class over the short term. To determine the effect of first-line bosentan therapy on survival, this study followed 169 patients with PPH treated with bosentan in two placebo-controlled trials and their extensions. Data on survival and alternative treatments were collected from September 1999 (start of the first placebo-controlled study) to December 31, 2002. Observed survival up to 36 months was reported as Kaplan-Meier estimates and compared with predicted survival as determined for each patient by the National Institutes of Health Registry formula. Kaplan-Meier survival estimates were 96% at 12 months and 89% at 24 months. In contrast, predicted survival was 69% and 57%, respectively. In addition, at the end of 12 and 24 months, 85% and 70% of patients, respectively, remained alive and on bosentan monotherapy. Factors that predicted a worse outcome included World Health Organization Functional Class IV and 6-min walk distance below the median (358 m) at baseline. First-line bosentan therapy was found to improve survival in patients with advanced primary pulmonary hypertension.

NoC synthesis flow for customized domain specific multiprocessor systems-on-chip

Abstract: The growing complexity of customizable single-chip multiprocessors is requiring communication resources that can only be provided by a highly-scalable communication infrastructure. This trend is exemplified by the growing number of network-on-chip (NoC) architectures that have been proposed recently for system-on-chip (SoC) integration. Developing NoC-based systems tailored to a particular application domain is crucial for achieving high-performance, energy-efficient customized solutions. The effectiveness of this approach largely depends on the availability of an ad hoc design methodology that, starting from a high-level application specification, derives an optimized NoC configuration with respect to different design objectives and instantiates the selected application specific on-chip micronetwork. Automatic execution of these design steps is highly desirable to increase SoC design productivity. This work illustrates a complete synthesis flow, called Netchip, for customized NoC architectures, that partitions the development work into major steps (topology mapping, selection, and generation) and provides proper tools for their automatic execution (SUNMAP, xpipescompiler). The entire flow leverages the flexibility of a fully reusable and scalable network components library called xpipes, consisting of highly-parameterizable network building blocks (network interface, switches, switch-to-switch links) that are design-time tunable and composable to achieve arbitrary topologies and customized domain-specific NoC architectures. Several experimental case studies are presented In the work, showing the powerful design space exploration capabilities of the proposed methodology and tools.

Angina With “Normal” Coronary Arteries: A Changing Philosophy

Abstract: ContextMany women with angina are told that they have no significant heart disease following demonstration of normal or near-normal coronary arteries and are offered no specific treatment beyond reassurance.Evidence AcquisitionMEDLINE and the Cochrane Database of Systematic Reviews were searched from their start dates until June 2004 for analysis using specific key words including diagnosis and therapy of angina with normal angiography and angina with normal coronary arteries. Reference lists of published articles and data of meeting presentations were also consulted.Evidence SynthesisNormal or nonobstructive coronary disease at angiography is not uncommon and occurs in 10% of women presenting with ST-segment elevation myocardial infarction compared with 6% in men. Patients with evidence of myocardial ischemia or myocardial infarction and nonobstructive atherosclerotic disease of the coronary arteries are more likely to be women and nonwhite. Symptoms are often indistinguishable from those with obstructive coronary artery disease. The prognosis of patients with unstable angina and nonobstructive atherosclerotic coronary artery disease is not benign and includes a 2% risk of death or myocardial infarction at 30 days of follow-up. Recent work has shown that at least 20% of women with normal or nonobstructive angiography have myocardial ischemia, likely due to atherosclerosis-related endothelial dysfunction, which itself is associated with an increased risk of later adverse cardiac events and development of frank future obstructive disease. Randomized placebo-controlled studies have demonstrated that tricyclic antidepressants, β-blockers, angiotensin-converting enzyme inhibitors, L-arginine, statins, and exercise may relieve symptoms, vascular dysfunction, or both; however, longer-term studies evaluating cardiac event rates need to be performed.ConclusionsPatients with chest pain and normal or nonobstructive coronary angiograms are predominantly women, and many have a prognosis that is not as benign as commonly thought. Assessment of endothelial function may help identify patients at risk for future cardiac events. Therapy should be directed at symptom relief with tricyclic agents and β-blockers, and aggressive antiatherosclerotic therapy with statins, angiotensin-converting enzyme inhibitors, or both should be applied when risk factors are present or prognostic risk is high. Large-scale randomized trials need to be conducted to determine optimal ways of preventing clinical events.

Multipotent mesenchymal stem cells with immunosuppressive activity can be easily isolated from dental pulp.

Abstract: Background Bone marrow mesenchymal stem cells (MSCs) are currently being investigated in preclinical and clinical settings because of their multipotent differentiative capacity or, alternatively, their immunosuppressive function. The aim of this study was to evaluate dental pulp (DP) as a potential source of MSCs instead of bone marrow (BM). Methods Flow cytometric analysis showed that DP-MSCs and BM-MSCs were equally SH2, SH3, SH4, CD29 and CD 166 positive. The in vitro proliferative kinetics of MSCs were measured by 3H-thymidine incorporation uptake. The immunosuppressive function of MSCs was then tested by coculturing PHA-stimulated allogeneic T cells with or without MSCs for 3 days. Results BM-MSCs could be differentiated in vitro into osteogenic, chondrogenic and adipogenic lineages. DP-MSCs showed osteogenic and adipocytic differentiation, but did not differentiate into chondrocytes. Although DP-MSCs grow rapidly in vitro between day 3 and day 8 of culture and then decrease their proliferation by day 15, BM-MSCs have a stable and continuous proliferation over the same period of time. The addition of DP-MSCs or BM-MSCs resulted in 91 +/- 4% and 75 +/- 3% inhibition of T cell response, respectively, assessed by a 3H-thymidine assay. Conclusions Dental pulp is an easily accessible and efficient source of MSCs, with different kinetics and differentiation potentialities from MSCs as isolated from the bone marrow. The rapid proliferative capacity together with the immunoregulatory characteristics of DP-MSCs may prompt future studies aimed at using these cells in the treatment or prevention of T-cell alloreactivity in hematopoietic or solid organ allogeneic transplantation.

Fermentation of Fructooligosaccharides and Inulin by Bifidobacteria: a Comparative Study of Pure and Fecal Cultures

Abstract: The utilization of fructooligosaccharides (FOS) and inulin by 55 Bifidobacterium strains was investigated. Whereas FOS were fermented by most strains, only eight grew when inulin was used as the carbon source. Residual carbohydrates were analyzed by high-performance anion-exchange chromatography with pulsed amperometric detection after batch fermentation. A strain-dependent capability to degrade fructans of different lengths was observed. During batch fermentation on inulin, the short fructans disappeared first, and then the longer ones were gradually consumed. However, growth occurred through a single uninterrupted exponential phase without exhibiting polyauxic behavior in relation to the chain length. Cellular β-fructofuranosidases were found in all of the 21 Bifidobacterium strains tested. Four strains were tested for extracellular hydrolytic activity against fructans, and only the two strains which ferment inulin showed this activity. Batch cultures inoculated with human fecal slurries confirmed the bifidogenic effect of both FOS and inulin and indicated that other intestinal microbial groups also grow on these carbon sources. We observed that bifidobacteria grew by cross-feeding on mono- and oligosaccharides produced by primary inulin intestinal degraders, as evidenced by the high hydrolytic activity of fecal supernatants. FOS and inulin greatly affected the production of short-chain fatty acids in fecal cultures; butyrate was the major fermentation product on inulin, whereas mostly acetate and lactate were produced on FOS.

The HELLAS2XMM Survey. VII. The Hard X-Ray Luminosity Function of AGNs up to z = 4: More Absorbed AGNs at Low Luminosities and High Redshifts

Abstract: We have determined the cosmological evolution of the density of active galactic nuclei (AGNs) and of their NH distribution as a function of the unabsorbed 2–10 keV luminosity up to redshift 4. We used the HELLAS2XMM sample combined with other published catalogs, yielding a total of 508 AGNs. Our best fit is obtained with a luminosity-dependent density evolution (LDDE) model where low-luminosity (LX � 10 43 ergs s � 1 ) AGNs peak at z � 0:7, while high-luminosity AGNs (LX > 10 45 ergs s � 1 )p eak atz � 2:0. A pure luminosity evolution model (PLE) can instead be rejected. There is evidence that the fraction of absorbed (NH > 10 22 cm � 2 ) AGNs decreases with the intrinsic X-ray luminosity and increases with the redshift. Our best-fit solution provides a good fit to the observed counts, the cosmic X-ray background, and to the observed fraction of absorbed AGNs as a function of the flux in the 10 � 15 ergs cm � 2 s � 1 10 44 ergs s � 1 ) AGNs have a density of 267 deg � 2 at fluxesS2� 10 > 10 � 15 ergs cm � 2 s � 1 . Using these results, "# (

Innate immunity and inflammation in ageing: a key for understanding age-related diseases.

Abstract: The process of maintaining life for the individual is a constant struggle to preserve his/her integrity. This can come at a price when immunity is involved, namely systemic inflammation. Inflammation is not per se a negative phenomenon: it is the response of the immune system to the invasion of viruses or bacteria and other pathogens. During evolution the human organism was set to live 40 or 50 years; today, however, the immune system must remain active for much a longer time. This very long activity leads to a chronic inflammation that slowly but inexorably damages one or several organs: this is a typical phenomenon linked to ageing and it is considered the major risk factor for age-related chronic diseases. Alzheimer's disease, atherosclerosis, diabetes and even sarcopenia and cancer, just to mention a few – have an important inflammatory component, though disease progression seems also dependent on the genetic background of individuals. Emerging evidence suggests that pro-inflammatory genotypes are related to unsuccessful ageing, and, reciprocally, controlling inflammatory status may allow a better chance of successful ageing. In other words, age-related diseases are "the price we pay" for a life-long active immune system: this system has also the potential to harm us later, as its fine tuning becomes compromised. Our immune system has evolved to control pathogens, so pro-inflammatory responses are likely to be evolutionarily programmed to resist fatal infections with pathogens aggressively. Thus, inflammatory genotypes are an important and necessary part of the normal host responses to pathogens in early life, but the overproduction of inflammatory molecules might also cause immune-related inflammatory diseases and eventually death later. Therefore, low responder genotypes involved in regulation of innate defence mechanisms, might better control inflammatory responses and age-related disease development, resulting in an increased chance of long life survival in a "permissive" environment with reduced pathogen load, medical care and increased quality of life.