2,876 research outputs found
Load distribution in small world networks
In this paper we introduce a new model of data packet transport, based on a
stochastic approach with the aim of characterizing the load distribution on
complex networks. Moreover we analyze the load standard deviation as an index
of uniformity of the distribution of packets within the network, to
characterize the effects of the network topology. We measure such index on the
model proposed by Watts and Strogatz as the redirection probability is
increased. We find that the uniformity of the load spread is maximized in the
intermediate region, at which the small world effect is observed and both
global and local efficiency are high. Moreover we analyze the relationship
between load centrality and degree centrality as an approximate measure of the
load at the edges. Analogous results are obtained for the load variance
computed at the edges as well as at the vertices.Comment: 6 pages, 5 figures. Included in conference proceedings International
Conference PhysCon 2005 August 24-26, 2005, Saint Petersburg, RUSSI
Leaders\u2019 competence and warmth: Their relationships with employees\u2019 well-being and organizational effectiveness
The aim of this work was to investigate competence and warmth \u2014 the two basic dimensions of social judgment \u2014 as dimensions employees use to evaluate their supervisors. A mediation model was tested in which supervisor\u2019s perceived competence and warmth were associated with relevant outcomes (lower burnout, weaker turnover intentions, more frequent citizenship behaviors) through the mediation of affective organizational commitment (AOC). In Study 1, data were collected from employees of a company in the water service sector. In Study 2, participants were financial promoters. In Study 3, the sample included employees from different organizations. As hypothesized, the perception of one\u2019s supervisor as competent (Studies 1-3) and warm (Study 3) was related to employees\u2019 lower burnout, weaker turnover intentions, more frequent prosocial behaviors through the mediation of AOC. Theoretical and practical implications of findings are discussed
Contribution to the vascular flora of Papasidero (north-western Calabria, Italy)
A floristic survey of the Papasidero municipality (54.65 km2) was carried out from 2008 to 2011, allowing us to list 580 specific and infraspecific taxa (567 verified by us), belonging to 353 genera and 89 families. Several species are rather interesting from a phytogeographic and/or conservation point of view. 14 exotic species were also recorded, 10 of which are considered invasive in the regional flora. The most represented families are Asteraceae (66 taxa), Fabaceae (56), Lamiaceae (40), Poaceae (31), while most represented genera are Trifolium (11), Euphorbia and Ophrys (9), Lathyrus and Geranium (8). Biological and chorological spectra show a clear dominance of Hemicriptophytes and Mediterranean elements respectively, as one can expect based on the climatic conditions of the area at issues
Impact of right ventricular size on ECG after percutaneous closure of atrial septal defect with Amplatzer Septal Occluder.
To assess ECG changes after percutaneous atrial septal defect (ASD) closure in children with significant left-to-right shunt.
Analysis of data of 36 consecutive children with an ASD who had successful percutaneous ASD closure with an Amplatzer Septal Occluder. Assessment comprised echocardiography and ECG the day before and after the procedure and at 1, 6 and 12 months follow-up.
The median age (interquartile range) of children was 7.3 (5.3) years. On the day after the procedure the end diastolic diameter of the right ventricle showed already a diminution (34 (12) mm/m2 before intervention vs. 32 (12) mm/m2). ECG changes were first observed at 1 month follow-up (PR interval before intervention 139 (20) ms vs. 132 (20) ms; QRS duration 88 (18) ms vs. 82 (19) ms) and at 6 months follow-up (QRS axis 77 degrees (33) before intervention vs. 72 degrees (53)). With the exception of the QRS duration, ECG intervals and axis were in a normal range in all patients before the procedure. Median QRS duration normalised at 1 year follow-up (83 (8) ms).
After transcatheter ASD closure, decrease in right ventricular size began rapidly and was followed by reduction of the QRS duration and PR interval within weeks. Shifting to the left of the QRS axis was observed within 6 months follow-up. This study showed that ECG changes due to right ventricular volume overload can regress and normalise after percutaneous ASD closure in children
Automatic synchronisation of the cell cycle in budding yeast through closed-loop feedback control
The cell cycle is the process by which eukaryotic cells replicate. Yeast cells cycle asynchronously with each cell in the population budding at a different time. Although there are several experimental approaches to synchronise cells, these usually work only in the short-term. Here, we build a cyber-genetic system to achieve long-term synchronisation of the cell population, by interfacing genetically modified yeast cells with a computer by means of microfluidics to dynamically change medium, and a microscope to estimate cell cycle phases of individual cells. The computer implements a controller algorithm to decide when, and for how long, to change the growth medium to synchronise the cell-cycle across the population. Our work builds upon solid theoretical foundations provided by Control Engineering. In addition to providing an avenue for yeast cell cycle synchronisation, our work shows that control engineering can be used to automatically steer complex biological processes towards desired behaviours similarly to what is currently done with robots and autonomous vehicles
A yeast synthetic network for in-vivo assessment of reverse engineering and modelling.
Systems biology approaches are extensively used to model and reverse engineer gene regulatory networks from experimental data. Conversely, synthetic biology allows ‘‘de novo’’ construction of a regulatory network to seed new functions in the cell. At present, the usefulness and predictive ability of modeling and reverse engineering cannot be assessed and compared rigorously. We built in the yeast Saccharomyces cerevisiae a synthetic network, IRMA, for in vivo ‘‘benchmarking’’ of reverse-engineering and modeling approaches. The network is composed of five genes regulating each other through a variety of regulatory interactions; it is negligibly affected by endogenous genes, and it is responsive to small molecules. We measured time series and steady-state expression data after multiple perturbations. These data were used to assess state-of-the-art modeling and reverse-engi- neering techniques. A semiquantitative model was able to capture and predict the behavior of the network. Reverse engineering based on differential equations and Bayesian networks correctly inferred regulatory interactions from the experimental data
Localisation of mediterranean Kaposi's sarcoma in Morgagni's ventricle
Objective: Head and neck involvement in Kaposi\u2019s Sarcoma (KS) is not unusual . However, laryngeal involvement is a relatively infrequent manifestation and ENT specialists should consider it in differential diagnosis in laryngeal lesions of AIDS patients and/or subjects from the Mediterranean area.
Methods: Case report and review of the literature in English
Clinical Case: Male patient presenting with a three- month history of cough and acute dispnoea. Laryngoscopy identified a laryngeal mass occluding the glottic plane. Tracheotomy was then performed and the laryngeal lesion was removed. Histopathology showed neoplastic spindle cells that were positive to immunostain with CD-31 and CD-34, and immunoreactivity for HHV-8 was present. A diagnosis of KS was then suspected and confirmed after dermatological inspection.
Conclusions: Purple vascular mass lesions should lead in ENT to a high index of suspicion to exclude systemic diseases. Laryngeal KS must be included in the differential diagnosis of pigmented laryngeal lesions to plan correct managemen
Production system and seasonal effects on textural properties of two-month ripened goat's cheese
Since the 1990s, there has been a revival in goat rearing and a resumption in the making of goat’s cheeses in the Province of Trento. Given this, and the local interest in maintaining the production and its traditions, a qualitative description of the goat’s cheeses is desirable. In this study, texture profile analysis, TPA, was used to examine the variability of the rheological properties, depending on production system and season, in raw milk semicooked paste goat’s cheese, ripened for two months, as the Trento Goat Cheese of Traditional Agrifood Products (D.M. n. 350, 1999)
- …