5,105 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
HLA Class I or Class II and Disease Association: Catch the Difference if You Can
The association of autoimmune diseases with HLA has been known for many decades. To date, however, the underlying mechanisms have not been fully understood.
The recently introduced genome-wide association studies (GWAS) have suggested that several genes converging in common pathways contribute to the genetic susceptibility in such disorders. Nevertheless, for most autoimmune/autoinflammatory diseases, the HLA genes are by far the strongest risk factors. The basis of some associations has now been elucidated, particularly in those cases in which exogenous factors are involved
Ankylosing Spondylitis: a trade Off of HLA-B27, ERAP, and pathogen interconnections? Focus on Sardinia
The frequency of HLA-B27 in patients with Ankylosing Spondylitis (AS) is over 85%. There are more than 170 recognized HLA-B27 alleles but the majority of them is not sufficiently represented for genetic association studies. So far only two alleles, the HLA-B*2706 in Asia and the HLA-B*2709 in Sardinia, have not been found to be associated with AS. The highly homogenous genetic structure of the Sardinian population has favored the search of relevant variants for disease-association studies. Moreover, malaria, once endemic in the island, has been shown to have contributed to shape the native population genome affecting the relative allele frequency of relevant genes. In Sardinia, the prevalence of HLA-B*2709, which differs from the strongly AS-associated B*2705 prototype for one amino acid (His/Asp116) in the F pocket of the peptide binding groove, is around 20% of all HLA-B27 alleles. We have previously hypothesized that malaria could have contributed to the establishment of this allele in Sardinia. Based on our recent findings, in this perspective article we speculate that the Endoplasmic Reticulum Amino Peptidases, ERAP1 and 2, associated with AS and involved in antigen presentation, underwent co-selection by malaria. These genes, besides shaping the immunopeptidome of HLA-class I molecules, have other biological functions that could also be involved in the immunosurveillance against malaria
CAD/CAM Diagnostic Esthetic Functional Splint (DEFS) as a removable prototype to evaluate the final prosthetic rehabilitation: a narrative review.
The main objective of this narrative review was to provide an overview of DEFS (Diagnostic Esthetic Functional Splint), namely CAD/CAM manufactured, “snap-retained”, tooth-colored splints available by materials exhibiting a certain degree of elasticity (like polycarbonates or acetal resins) for restoring function, esthetics and occlusion in several clinical situations, before or as an intermediate alternative to undergoing the final treatment. The search strategy included all papers dealing with snap-retained prosthetic systems and was based on a literature review of papers available in electronic databases (Pubmed/Medline, Evidence-Based Dentistry, BMJ Evidence-Based Medicine, Dynamed, Embase, BMJ Clinical Evidence, Web of Science, Scientific reports); eligible papers were researched on Opengreyand a manual search was performed, as well. From the electronic databases emerged 13,199 records, many of which were duplicates. The grey literature and the manual research did not produce any eligible article. After duplicates removal, 7690 records were obtained. Titles, abstracts and keywords were analyzed. The studies concerning the topic of interest were examined by the reviewers and discussed. Although no evidence-based data were found in the literature, according to the authors’ clinical experience, the DEFS (Diagnostic Esthetic Functional Splint) is a very promising solution in multiple clinical situations, due to its diagnostic, therapeutical, functional and esthetic versatility
Measurement of the Gravity-Field Curvature by Atom Interferometry
We present the first direct measurement of the gravity-field curvature based
on three conjugated atom interferometers. Three atomic clouds launched in the
vertical direction are simultaneously interrogated by the same atom
interferometry sequence and used to probe the gravity field at three equally
spaced positions. The vertical component of the gravity-field curvature
generated by nearby source masses is measured from the difference between
adjacent gravity gradient values. Curvature measurements are of interest in
geodesy studies and for the validation of gravitational models of the
surrounding environment. The possibility of using such a scheme for a new
determination of the Newtonian constant of gravity is also discussed.Comment: 5 pages, 3 figure
Cooling of Sr to high phase-space density by laser and sympathetic cooling in isotopic mixtures
Based on an experimental study of two-body and three-body collisions in
ultracold strontium samples, a novel optical-sympathetic cooling method in
isotopic mixtures is demonstrated. Without evaporative cooling, a phase-space
density of is obtained with a high spatial density that should
allow to overcome the difficulties encountered so far to reach quantum
degeneracy for Sr atoms.Comment: 5 pages, 4 figure
Dome Down Laparoscopic Cholecystectomy: Our Experience and the State of Art
Introduction: Laparoscopic Cholecystectomy is nowadays the gold standard technique for
benign gallbladder disease both in elective and emergency surgery. But it is even true that in very
acute cholecystitis when the tissues are inflamed and the anatomy can be difficult to recognize, the
classic laparoscopic approach can lead to biliary and vascular injuries. Dome down laparoscopic
approach can be used to avoid conversion to open surgery and decrease surgical complications.
Methods: A retrospective record of all Cholecystectomy carried out in our unit by experienced
surgeons from January 2013 to August 2017 was examined. Cases were divided by surgical
technique: Classical laparoscopic technique, Open cholecystectomy, Laparoscopic converted to
open cholecystectomy, Dome down laparoscopic Cholecystectomy (DDLC). A systematic literature
search was performed using PubMedz and Embase databases. The search was limited to studies
on humans and to those reported in the English language between January 2009 and December
2016.
Results and discussion: 194 cholecystectomy were performed, among these 163 with
laparoscopic technique and 3% of all laparoscopic approached cholecystectomy were performed
as DDLC. The mean hospital stay was 5 days (2-11). 1 out of 5 patients needed postoperatory
ERCP and endobiliary stent was positioned removed in 30 days with no other complications.
Other 4 patients were evaluated after 1 week from dismission with no evidence of postoperative
complications.
Conclusion: Dome down cholecystectomy is a feasible and safe procedure; it avoids biliary
and vascular injuries in difficult cholecystectomy. It can still be improved by the combination
with ultrasonic devices or with new surgical techniques such as Single-incision Laparoscopic
cholecistectomy
Long-lived Bloch oscillations with bosonic Sr atoms and application to gravity measurement at micrometer scale
We report on the observation of Bloch oscillations on the unprecedented time
scale of severalseconds. The experiment is carried out with ultra-cold bosonic
strontium-88 loaded into a vertical optical standing wave. The negligible
atom-atom elastic cross section and the absence of spin makes Sr an
almost ideal Bose gas insensitive to typical mechanisms of decoherence due to
thermalization and to external stray fields. The small size enables precision
measurements of forces at micrometer scale. This is a challenge in physics for
studies of surfaces, Casimir effects, and searches for deviations from
Newtonian gravity predicted by theories beyond the standard model
A plug and play transparent communication layer for cloud robotics architectures
The cloud robotics paradigm aims at enhancing the abilities of robots by using cloud services, but it still poses several challenges in the research community. Most of the current literature focuses on how to enrich specific robotic capabilities, overlooking how to effectively establish communication between the two fields. Our work proposes a “plug-and-play” solution to bridge the communication gap between cloud and robotic applications. The proposed solution is designed based on the mature WebSocket technology and it can be extended to any ROS-based robotic platform. The main contributions of this work are the definition of a reliable autoconnection/autoconfiguration mechanism as well as to outline a scalable communication layer that allows the effective control of multiple robots from multiple users. The “plug-and-play” solution was evaluated in both simulated and real scenarios. In the first case, the presence of users and robots was simulated with Robot Operating System (ROS) nodes running on five machines. In the real scenario, three non-expert users teleoperated, simultaneously, three remote robots by using the proposed communication layer with different networking protocols. Results confirmed the reliability at different levels: at startup (success_rate = 100%); during high-rate communications (message_lost = 0%); in performing open-loop spiral trajectories with enhancement, with respect to similar works; and in the quality of simultaneous teleoperations
- …