Coalitions in international litigation: a network perspective.

We apply network science principles to analyse the coalitions formed by European Union nations and institutions during litigation proceedings at the European Court of Justice. By constructing Friends and Foes networks, we explore their characteristics and dynamics through the application of cluster detection, motif analysis and duplex analysis. Our findings demonstrate that the Friends and Foes networks exhibit disassortative behaviour, highlighting the inclination of nodes to connect with dissimilar nodes. Furthermore, there is a correlation among centrality measures, indicating that member states and institutions with a larger number of connections play a prominent role in bridging the network. An examination of the modularity of the networks reveals that coalitions tend to align along regional and institutional lines, rather than national government divisions. Additionally, an analysis of triadic binary motifs uncovers a greater level of reciprocity within the Foes network compared to the Friends network. This article is part of the theme issue 'A complexity science approach to law and governance'.

The role of complexity for digital twins of cities.

We argue that theories and methods drawn from complexity science are urgently needed to guide the development and use of digital twins for cities. The theoretical framework from complexity science takes into account both the short-term and the long-term dynamics of cities and their interactions. This is the foundation for a new approach that treats cities not as large machines or logistic systems but as mutually interwoven self-organizing phenomena, which evolve, to an extent, like living systems.

Silent thyroiditis following vaccination against COVID-19: report of two cases.

PURPOSE: It is well established that thyroiditis and other thyroid disorders can be induced by COVID-19 infection, but there is limited information about the autoimmune/inflammatory syndrome induced by adjuvants (ASIA) after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. We report two cases of thyrotoxicosis following SARS-CoV-2 vaccine. METHODS AND RESULTS: Two young health care peoples (wife and husband) received a first dose of SARS-CoV-2 vaccine, and few weeks later developed clinical manifestations of thyroid hyperactivity, with increased thyroid hormone levels on thyroid function tests, suppressed thyroid-stimulating hormone and negative antithyroid antibodies, despite being healthy before vaccination. They were diagnosed at the 4th week after first dose of SARS-Cov-2 vaccine as silent thyroiditis and followed without treatment, since their symptoms were not severe. At the 6th week, the patients became wholly asymptomatic and their thyroid function returned to normal. CONCLUSIONS: Thyrotoxicosis can occur after SARS-CoV-2 vaccination probably related to silent thyroiditis.

Adoption of TSH Reflex algorithm in an Italian clinical laboratory.

BACKGROUND: TSH Reflex is an automated diagnostic algorithm which follows the rule "If ... then", in which the initial determination of TSH is followed by the determination of fT4, and possibly of fT3, if TSH is not within the reference limits. The aim of our study was to evaluate the results of the introduction and implementation of the test "TSH Reflex", which started in late 2013 in the hospital of Grosseto, comparing the requests of thyroid hormones for external patients, in 2012, 2014 and 2015. METHODS: In our study we analyzed the number of thyroid tests prescribed in 2012, 2014 and 2015 and we calculated the increase in prescription of "TSH Reflex" from 2014 to 2015; the prescriptive appropriateness, after the introduction of the "TSH Reflex", through the ratios TSH/FT4, TSH/FT3 and the ratio "TSH Reflex"/TSH. Finally we calculated the total spending for the reagents in 2012, 2014 and 2015 and the consequent savings in euros (the costs of the reagents did not change during that time). RESULTS: Requests for TSH decreased by 4.6% in 2014, compared to 2012 and by 5.4% in 2015 compared to 2014, with a 9.8% reduction in 2015 compared to 2012. The requests for FT4 decreased by 11.5%, comparing 2014 with 2012, by 5.3% comparing 2015 with 2014, with a 16.2% reduction in 2015 compared to 2012. The requests for FT3 decreased by 13.3% in 2014 compared to 2012 and by 8.4% in 2015 compared to 2014, with a 20.6% reduction in 2015 compared to 2012. The appropriateness, evaluated the indicator TSH/FT4, increased by 7.6%, comparing 2014 with 2012, and remained unchanged in 2015. In 2012 71,134 euros were spent, 63,998 euros in 2014, 60,055 euros in 2015, resulting in a saving of € 11,079 in 2015 compared to 2012. The spending for "TSH Reflex" should be subtracted (1,964 Euros in 2015) from the previous savings. CONCLUSIONS: The improvement of the efficiency and the prescriptive appropriateness was better in 2014, the first year of implementation of the "TSH Reflex". The overall assessment suggests that the 2014 results are attributable to the letters that general practitioners received in December 2013, with a temporary increase of the use of the test. We need further analyses with the same indicators in order to assess the possibility of additional improvements in the future.

Can PSA Reflex Algorithm be a valid alternative to other PSA-based prostate cancer screening strategies?

BACKGROUND: The available laboratory tests for the differential diagnosis of prostate cancer, are represented by the total PSA, the free PSA, and the free/total PSA ratio. In Italy most of doctors tend to request both total and free PSA for their patients even in cases where the total PSA doesn't justify the further request of free PSA, with a consequent growth of the costs for the National Health System. The aim of our study was to predict the saving in Euro (due to reagents) and reduction in free PSA tests, applying the "PSA Reflex" algorithm. METHODS: We calculated the number of total PSA and free PSA exams performed in 2014 in the Hospital of Grosseto and, simulating the application of the "PSA Reflex" algorithm in the same year, we calculated the decrease in the number of free PSA requests and we tried to predict the Euro savings in reagents, obtained from this reduction. RESULTS: In 2014 in the Hospital of Grosseto 25,955 total PSA tests have been performed: 3,631 (14%) resulted greater than 10 ng / ml; 7,686 (29.6%) between 2 and 10 ng / ml; 14,638 (56.4%) lower than 2 ng / ml. The performed free PSA tests were 16904. Simulating the use of "PSA Reflex" algorithm, the free PSA tests would be performed only in cases with total PSA values between 2 and 10 ng / mL with a saving of 54.5% of free PSA exams and of 8,971 euros, only for reagents. CONCLUSIONS: Our study showed that the "PSA Reflex" algorithm is a valid alternative leading to a reduction of the costs. The estimated intralaboratory savings, due to the reagents, seem to be modest, however, they are followed by the additional savings due to the other diagnostic processes for prostate cancers.

A network approach to orthodontic diagnosis.

BACKGROUND: Network analysis, a recent advancement in complexity science, enables understanding of the properties of complex biological processes characterized by the interaction, adaptive regulation, and coordination of a large number of participating components. OBJECTIVE: We applied network analysis to orthodontics to detect and visualize the most interconnected clinical, radiographic, and functional data pertaining to the orofacial system. MATERIALS AND METHODS: The sample consisted of 104 individuals from 7 to 13 years of age in the mixed dentition phase without previous orthodontic intervention. The subjects were divided according to skeletal class; their clinical, radiographic, and functional features were represented as vertices (nodes) and links (edges) connecting them. RESULTS: Class II subjects exhibited few highly connected orthodontic features (hubs), while Class III patients showed a more compact network structure characterized by strong co-occurrence of normal and abnormal clinical, functional, and radiological features. Restricting our analysis to the highest correlations, we identified critical peculiarities of Class II and Class III malocclusions. CONCLUSIONS: The topology of the dentofacial system obtained by network analysis could allow orthodontists to visually evaluate and anticipate the co-occurrence of auxological anomalies during individual craniofacial growth and possibly localize reactive sites for a therapeutic approach to malocclusion.

Invasion percolation on a tree and queueing models.

We study the properties of the Barabási model of queuing [A.-L. Barabási, Nature (London) 435, 207 (2005); J. G. Oliveira and A.-L. Barabási, Nature (London) 437, 1251 (2005)] in the hypothesis that the number of tasks grows with time steadily. Our analytical approach is based on two ingredients. First we map exactly this model into an invasion percolation dynamics on a Cayley tree. Second we use the theory of biased random walks. In this way we obtain the following results: the stationary-state dynamics is a sequence of causally and geometrically connected bursts of execution activities with scale-invariant size distribution. We recover the correct waiting-time distribution PW(tau) approximately tau(-3/2) at the stationary state (as observed in different realistic data). Finally we describe quantitatively the dynamics out of the stationary state quantifying the power-law slow approach to stability both in single dynamical realization and in average. These results can be generalized to the case of a stochastic increase in the queue length in time with limited fluctuations. As a limit case we recover the situation in which the queue length fluctuates around a constant average value.

Ensemble approach to the analysis of weighted networks.

We present an approach to the analysis of weighted networks, by providing a straightforward generalization of any network measure defined on unweighted networks, such as the average degree of the nearest neighbors, the clustering coefficient, the "betweenness," the distance between two nodes, and the diameter of a network. All these measures are well established for unweighted networks but have hitherto proven difficult to define for weighted networks. Our approach is based on the translation of a weighted network into an ensemble of edges. Further introducing this approach we demonstrate its advantages by applying the clustering coefficient constructed in this way to two real-world weighted networks.

Invasion percolation and critical transient in the Barabási model of human dynamics.

We introduce an exact probabilistic description for L=2 of the Barabási model for the dynamics of a list of L tasks. This permits us to study the problem out of the stationary state and to solve explicitly the extremal limit case where a critical behavior for the waiting time distribution is observed. This behavior deviates at any finite time from that of the stationary state. We study also the characteristic relaxation time for finite time deviations from stationarity in all cases showing that it diverges in the extremal limit, confirming that these deviations are important at all time.

Retroperitoneoscopic lumbar sympathectomy for nonreconstructable arterial occlusive disease.

AIM: The aim of this study was to present our experience with video-assisted lumbar sympathectomy for non-reconstructive arterial occlusive disease in a series of 23 consecutive patients whose predominant symptoms were unilateral rest pain, limited skin ulcerations or gangrene of the toes. METHODS: All the procedures were performed with retroperitoneal approach, dorsal position of the patient and simple digital dissection of the retroperitoneal space. RESULTS: The operations were successfully performed in all patients except for 2, who immediately underwent open conversion. A urinoma caused by ureteral lesion was the only severe complication in this series. The mean operative time of the procedure was 55 min and the hospital stay was 2 or 3 days. No parenteral analgesics were administered postoperatively. At 1 month from operation, 20 patients out of 23 had significant relief of rest pain and improvement of ischemic lesions. After a median follow-up of 36 months, 2 patients had died, 4 underwent some type of distal amputation, 1 had recurrent rest pain and the other 16 reported persistent improvement of pain or dystrophic changes. CONCLUSIONS: Retro-peritoneoscopic technique appears the modern and less invasive version of the lumbar surgical sympathectomy.

Preferential attachment in the growth of social networks: the internet encyclopedia Wikipedia.

We present an analysis of the statistical properties and growth of the free on-line encyclopedia Wikipedia. By describing topics by vertices and hyperlinks between them as edges, we can represent this encyclopedia as a directed graph. The topological properties of this graph are in close analogy with those of the World Wide Web, despite the very different growth mechanism. In particular, we measure a scale-invariant distribution of the in and out degree and we are able to reproduce these features by means of a simple statistical model. As a major consequence, Wikipedia growth can be described by local rules such as the preferential attachment mechanism, though users, who are responsible of its evolution, can act globally on the network.

Fitness model for the Italian interbank money market.

We use the theory of complex networks in order to quantitatively characterize the formation of communities in a particular financial market. The system is composed by different banks exchanging on a daily basis loans and debts of liquidity. Through topological analysis and by means of a model of network growth we can determine the formation of different group of banks characterized by different business strategy. The model based on Pareto's law makes no use of growth or preferential attachment and it reproduces correctly all the various statistical properties of the system. We believe that this network modeling of the market could be an efficient way to evaluate the impact of different policies in the market of liquidity.

Preferential exchange: strengthening connections in complex networks.

Many social, technological, and biological interactions involve network relationships whose outcome intimately depends on the structure of the network and on the strengths of the connections. Yet, although much information is now available concerning the structure of many networks, the strengths are more difficult to measure. Here we show that, for one particular social network, notably the e-mail network, a suitable measure of the strength of the connections can be available. We also propose a simple mechanism, based on positive feedback and reciprocity, that can explain the observed behavior and that hints toward specific dynamics of formation and reinforcement of network connections. Network data from contexts different from social sciences indicate that power-law, and generally broad, distributions of the connection strength are ubiquitous, and the proposed mechanism has a wide range of applicability.

Leiomyosarcoma of the popliteal artery: case report and review of the literature.

Vascular leiomyosarcomas are rare tumors, and only 21 have been described as developing in the systemic arteries. We present a case, the sixth in the literature, of a leiomyosarcoma originating in the popliteal artery of a 67-year-old woman treated with en bloc excision of the neoplasia and the artery followed by a popliteal tibioperoneal trunk bypass. The patient then was underwent adjuvant radiotherapy and chemotherapy. After 31 months of follow-up, the patient has mild claudication but does not have either recurrence or metastasis.

Scale-free networks from varying vertex intrinsic fitness.

A new mechanism leading to scale-free networks is proposed in this Letter. It is shown that, in many cases of interest, the connectivity power-law behavior is neither related to dynamical properties nor to preferential attachment. Assigning a quenched fitness value x(i) to every vertex, and drawing links among vertices with a probability depending on the fitnesses of the two involved sites, gives rise to what we call a good-get-richer mechanism, in which sites with larger fitness are more likely to become hubs (i.e., to be highly connected).

Local rigidity in sandpile models.

We address the problem of the role of the concept of local rigidity in the family of sandpile systems. We define rigidity as the ratio between the critical energy and the amplitude of the external perturbation and we show, in the framework of the dynamically driven renormalization group, that any finite value of the rigidity in a generalized sandpile model renormalizes to an infinite value at the fixed point, i.e., on a large scale. The fixed-point value of the rigidity allows then for a nonambiguous distinction between sandpilelike systems and diffusive systems. Numerical simulations support our analytical results.

Prosthetic replacement of the inferior vena cava and the iliofemoral vein for urologically related malignancies.

OBJECTIVE: To evaluate the feasibility and results of prosthetic venous replacement, as inferior vena cava (IVC) and iliofemoral vein resection and replacement are sometimes necessary when they are extensively involved by a large and fixed tumour thrombus from renal cell carcinoma (RCC) or other urological malignancies. PATIENTS AND METHODS: Five men and two women (age range 41-75 years) were treated over a 10-year period (1991-2001) by aggressive venous surgery to achieve complete tumour resection, with prosthetic graft replacement to re-establish venous flow. The tumours included RCC of the right kidney (two), retroperitoneal liposarcoma (two), bladder cancer (one), retroperitoneal fibrosarcoma (one) and inguino-pelvic lymphoma (one). Two patients had a vena caval replacement, of whom one had a circular reinforced PTFE and one a Dacron silver graft; five patients had either an iliofemoral or an ilio-iliac circular reinforced PTFE graft. The prosthetic diameter was 18-20 mm for the IVC grafts and 8-10 mm for the iliac grafts. In all the patients, graft patency was evaluated during the follow-up by colour flow duplex imaging, and in one it was determined by angio-computed tomography scan and venography. RESULTS: One patient died 30 days after surgery; of the remaining six patients one had no evidence of regional recurrence or metastatic disease at 12 months, and five died from recurrent tumour 8-30 months after surgery. The mean time to death was 23 months. At 3 months all six prosthesis were patent; at 6 months four were patent and at 12 months three of five prostheses were patent. CONCLUSION: Resecting and replacing the IVC allows complete tumour resection and avoids renal failure, providing durable relief from the symptoms of venous obstruction. Iliofemoral prosthetic reconstruction for urological-related malignancies represents a viable option to avoid venous engorgement and lower extremity swelling, at least in the early postoperative period. The mean time to death for the present patients must be considered the limit for these aggressive operations.

Probabilistic approach to the Bak-Sneppen model.

We study here the Bak-Sneppen model, a prototype model for the study of self-organized criticality. In this model several species interact and undergo extinction with a power-law distribution of activity bursts. Species are defined through their "fitness" whose distribution in the system is uniform above a certain threshold. Run time statistics is introduced for the analysis of the dynamics in order to explain the peculiar properties of the model. This approach based on conditional probability theory, takes into account the correlations due to memory effects. In this way, we may compute analytically the value of the fitness threshold with the desired precision. This represents a substantial improvement with respect to the traditional mean field approach.

Growing dynamics of Internet providers.

In this paper we present a model for the growth and evolution of Internet providers. The model reproduces the data observed for the Internet connection as probed by tracing routes from different computers. This problem represents a paramount case of study for growth processes in general, but can also help in the understanding the properties of the Internet. Our main result is that this network can be reproduced by a self-organized interaction between users and providers that can rearrange in time. This model can then be considered as a prototype model for the class of phenomena of aggregation processes in social networks.

Cellular models for river networks.

A cellular model introduced for the evolution of the fluvial landscape is revisited using extensive numerical and scaling analyses. The basic network shapes and their recurrence especially in the aggregation structure are then addressed. The roles of boundary and initial conditions are carefully analyzed as well as the key effect of quenched disorder embedded in random pinning of the landscape surface. It is found that the above features strongly affect the scaling behavior of key morphological quantities. In particular, we conclude that randomly pinned regions (whose structural disorder bears much physical meaning mimicking uneven landscape-forming rainfall events, geological diversity or heterogeneity in surficial properties like vegetation, soil cover or type) play a key role for the robust emergence of aggregation patterns bearing much resemblance to real river networks.