Phase separation and pairing regimes in the one-dimensional asymmetric Hubbard model

We address some open questions regarding the phase diagram of the one-dimensional Hubbard model with asymmetric hopping coefficients and balanced species. In the attractive regime we present a numerical study of the passage from on-site pairing dominant correlations at small asymmetries to charge-density waves in the region with markedly different hopping coefficients. In the repulsive regime we exploit two analytical treatments in the strong- and weak-coupling regimes in order to locate the onset of phase separation at small and large asymmetries respectively.Comment: 13 pages, RevTeX 4, 12 eps figures, some additional refs. with respect to v1 and citation errors fixe

Late postpancreatectomy hemorrhage after pancreaticoduodenectomy: is it possible to recognize risk factors?

CONTEXT: Post-pancreatectomy hemorrhage is one of the most common complications after pancreaticoduodenectomy. OBJECTIVE: To evaluate the late post-pancreatectomy hemorrhage rate according to the International Study Group of Pancreatic Surgery criteria and to recognize factors related to its onset. METHODS: A prospective study of 113 patients who underwent pancreaticoduodenectomy was conducted. Late post-pancreatectomy hemorrhage was defined according to the criteria of the International Study Group of Pancreatic Surgery. Demographic, clinical, surgical and pathological data were considered and related to late post-pancreatectomy hemorrhage. RESULTS: Thirty-one (27.4%) patients had a post-pancreatectomy hemorrhage. Twenty-five (22.1%) patients developed late post-pancreatectomy hemorrhage: 19 (16.8%) grade B, 6 (5.3%) grade C. Surgical re-operation was performed in 2 out of the 25 cases with late post-pancreatectomy hemorrhage (8.0%) grade C associated with postoperative pancreatic fistula. At univariate analysis, the only factor significantly related to late post-pancreatectomy hemorrhage was postoperative pancreatic fistula (P<0.001). Multivariate analysis underlined that the severity of postoperative pancreatic fistula (P<0.001) and pancreatic anastomosis (P=0.049) independently increased the risk of late hemorrhage. CONCLUSION: In patients undergoing pancreaticoduodenectomy, the criteria introduced by International Study Group of Pancreatic Surgery to define late postpancreatectomy hemorrhage are related to a higher incidence of hemorrhage than previously detected because they considered also mild hemorrhage

The Time of Flight System of the AMS-02 Space Experiment

The Time-of-Flight (TOF) system of the AMS detector gives the fast trigger to the read out electronics and measures velocity, direction and charge of the crossing particles. The new version of the detector (called AMS-02) will be installed on the International Space Station on March 2004. The fringing field of the AMS-02 superconducting magnet is $1.0\div2.5$ kG where the photomultiplers (PM) are installed. In order to be able to operate with this residual field, a new type of PM was chosen and the mechanical design was constrained by requiring to minimize the angle between the magnetic field vector and the PM axis. Due to strong field and to the curved light guides, the time resolution will be $150\div180$ ps, while the new electronics will allow for a better charge measurement.Comment: 5 pages, 4 figures. Proc. of 7th Int. Conf. on Adv. Tech. and Part. Phys., 15-19 October 2001,Como (Italy

Ultrasound as first line step in anaemia diagnostics

This review covers the role of ultrasonography as an essential non-invasive diagnostic approach when facing patients with anaemia, a common clinical problem. Abdomen ultrasound is well recognised as a first-line examination in the setting of blood loss, both acute and chronic. Less is clear about the additional opportunities, given by ultrasound in anaemia, due to the many other possible causes. Here we provide information on the utility of ultrasound in different contexts and a practical guide for clinicians facing anaemic patients

Converted laparoscopic distal pancreatectomy: is there an impact on patient outcome and total cost?

Purpose: Recent studies have reported worse outcomes of converted laparoscopic distal pancreatectomy (CLDP) with respect to total laparoscopic (TLDP) and open (ODP). The aim of the study was to evaluate the impact of conversion on patient outcome and on total cost. Methods: Patients requiring a conversion (CLDP) were compared with both TLDP and ODP patients. The relevant patient- and tumour-related variables were collected for each patient. Both intra and postoperative data were extracted. Propensity score matching (PSM) analysis was carried out to equate the groups compared. Results: Two hundred and five patients underwent DP, 105 (51.2%) ODPs, 81 (39.5%) TLDPs, and 19 (9.3%) CLDPs. After PSM, 19 CLDPs, 38 TLDPs, and 38 ODPs were compared. Patients who underwent CLDP showed a significantly longer operative time (P &lt; 0.001), and an increase in blood loss (P = 0.032) and total cost (P = 0.034) with respect to TLDP, and a significantly longer operative time (P &lt; 0.001), less frequent postoperative morbidity (P = 0.050), and a higher readmission rate (P = 0.035) with respect to ODP. Conclusion: Total laparoscopic pancreatectomy was superior regarding operative findings and total costs with respect to CLDP; ODP showed a higher postoperative morbidity rate and a lower readmission rate with respect to CLDP. However, the reasons for the readmission of patients who underwent CLDP were mainly related to postoperative pancreatic fistula (POPF) grade B which is usually due to pancreas texture. Thus, the majority of distal pancreatectomies can be started using a minimally invasive approach, performing an early conversion if necessary

Treatment of squamous cell carcinoma of the anal canal: A new strategies with anti-EGFR therapy and immunotherapy

The incidence of squamous cell carcinoma of the anal canal (SCAC) is increasing in both sexes but the standard treatment remains that of 20 years ago. However, interesting data have recently emerged on the use of anti-epidermal growth factor receptor (EGFR) agents and immunotherapy in advanced disease. Thus, new avenues of research are opening up that will hopefully lead to more effective therapeutic strategies. We provide an overview of the latest studies published on this tumor and discuss the possible future therapeutic options for combination therapy, anti-EGFR treatment and radiotherapy

A bizarre foreign body in the appendix: A case report

Foreign bodies are rare causes of appendicitis and, in most cases, ingested foreign bodies pass through the alimentary tract asymptomatically. However, ingested foreign bodies may sometimes remain silent within the appendix for many years without an inflammatory response. Despite the fact that cases of foreign-body-induced appendicitis have been documented, sharp and pointed objects are more likely to cause perforations and abscesses, and present more rapidly after ingestion. Various materials, such as needles and drill bits, as well as organic matter, such as seeds, have been implicated as causes of acute appendicitis. Clinical presentation can vary from hours to years. Blunt foreign bodies are more likely to remain dormant for longer periods and cause appendicitis through obstruction of the appendiceal lumen. We herein describe a patient presenting with a foreign body in his appendix which had been swallowed 15 years previously. The contrast between the large size of the foreign body, the long clinical history without symptoms and the total absence of any histological inflammation was notable. We suggest that an elective laparoscopic appendectomy should be offered to such patients as a possible management optio

Blumgart Anastomosis After Pancreaticoduodenectomy. A Comprehensive Systematic Review, Meta-Analysis, and Meta-Regression

Background: The superiority of Blumgart anastomosis (BA) over non-BA duct to mucosa (non-BA DtoM) still remains under debate. Methods: We performed a systematic search of studies comparing BA to non-BA DtoM. The primary endpoint was CR-POPF. Postoperative morbidity and mortality, post-pancreatectomy hemorrhage (PPH), delayed gastric emptying (DGE), reoperation rate, and length of stay (LOS) were evaluated as secondary endpoints. The meta-analysis was carried out using random effect. The results were reported as odds ratio (OR), risk difference (RD), weighted mean difference (WMD), and number needed to treat (NNT). Results: Twelve papers involving 2368 patients: 1075 BA and 1193 non-BA DtoM were included. Regarding the primary endpoint, BA was superior to non-BA DtoM (RD = 0.10; 95% CI: −0.16 to −0.04; NNT = 9). The multivariate ORs' meta-analysis confirmed BA's protective role (OR 0.26; 95% CI: 0.09 to 0.79). BA was superior to DtoM regarding overall morbidity (RD = −0.10; 95% CI: −0.18 to −0.02; NNT = 25), PPH (RD = −0.03; 95% CI −0.06 to −0.01; NNT = 33), and LOS (− 4.2&nbsp;days; −7.1 to −1.2 95% CI). Conclusion: BA seems to be superior to non-BA DtoM in avoiding CR-POPF

A Methodology and Simulation-Based Toolchain for Estimating Deployment Performance of Smart Collective Services at the Edge

Research trends are pushing artificial intelligence (AI) across the Internet of Things (IoT)-edge-fog-cloud continuum to enable effective data analytics, decision making, as well as the efficient use of resources for QoS targets. Approaches for collective adaptive systems (CASs) engineering, such as aggregate computing, provide declarative programming models and tools for dealing with the uncertainty and the complexity that may arise from scale, heterogeneity, and dynamicity. Crucially, aggregate computing architecture allows for 'pulverization': applications can be decomposed into many deployable micromodules that can be spread across the ICT infrastructure, thus allowing multiple potential deployment configurations for the same application logic. This article studies the deployment architecture of aggregate-based edge services and its implications in terms of performance and cost. The goal is to provide methodological guidelines and a model-based toolchain for the generation and simulation-based evaluation of potential deployments. First, we address this subject methodologically by proposing an approach based on deployment code generators and a simulation phase whose obtained solutions are assessed with respect to their performance and costs. We then tailor this approach to aggregate computing applications deployed onto an IoT-edge-fog-cloud infrastructure, and we develop a corresponding toolchain based on Protelis and EdgeCloudSim. Finally, we evaluate the approach and tools through a case study of edge multimedia streaming, where the edge ecosystem exhibits intelligence by self-organizing into clusters to promote load balancing in large-scale dynamic settings

Robust Online Magnet Demagnetization Diagnosis in Asymmetrical Six-Phase AC Permanent Magnet Motor Drives

Rotor magnets are critical components, which in case of fault, directly affect the performance of drives based on permanent magnet synchronous motors. Thus, monitoring the rotor magnets status is essential to ensure both high level of efficiency and service continuity. The present study focuses on the investigation of a new full-time domain-based method for the diagnosis of incipient rotor magnet demagnetization in a vector-controlled asymmetrical six-phase surface-mounted ac permanent magnet synchronous motor. The proposed strategy evaluates the rotor magnet demagnetization using a fault index derived from the control signals synthetized in the 5th subspace, and already available in the control system platform. The main advantages of the proposed new strategy are its simplicity of implementation, and effectiveness even under time-varying operating conditions as the employed control signals in specific subspaces have a dc behavior. Extensive numerical simulations and experimental tests, carried out at different speed and load levels, have shown the validity of the proposed method, leading to an effective diagnostic procedure for a vector-controlled asymmetrical six-phase surface-mounted ac PMSM