On the backward bifurcation of a vaccination model with nonlinear incidence

A compartmental epidemic model, introduced by Gumel and Moghadas [1], is considered. The model incorporates a nonlinear incidence rate and an imperfect preventive vaccine given to susceptible individuals. A bifurcation analysis is performed by applying the bifurcation method introduced in [2], which is based on the use of the center manifold theory. Conditions ensuring the occurrence of backward bifurcation are derived. The obtained results are numerically validated and then discussed from both the mathematical and the epidemiological perspective

THE SLOW CORONARY FLOW PHENOMENON IS NOT A GOOD PREDICTOR OF CORONARY MICROCIRCULATORY DYSFUNCTION AS ASSESSED BY ABSOLUTE CORONARY FLOW RESERVE IN PATIENTS WITH ANGIOGRAPHICALLY NORMAL CORONARY ARTERIES

The slow coronary flow phenomenon is not a good predictor of coronary microcirculatory dysfunction as assessed by absolute CFR. It might reflect, however, only a resting microcirculatory abnormality and probably remains a multifactorial phenomenon

Intraoperative assessment of fluid responsiveness in normotensive dogs under isoflurane anaesthesia

The aim of this study was to evaluate the incidence of fluid responsiveness (FR) to a fluid challenge (FC) in normotensive dogs under anaesthesia. The accuracy of pulse pressure variation (PPV), systolic pressure variation (SPV), stroke volume variation (SVV), and plethysmographic variability index (PVI) for predicting FR was also evaluated. Dogs were anaesthetised with methadone, propofol, and inhaled isoflurane in oxygen, under volume-controlled mechanical ventilation. FC was performed by the administration of 5 mL/kg of Ringer’s lactate within 5 min. Cardiac index (CI; L/min/m2), PPV, (%), SVV (%), SPV (%), and PVI (%) were registered before and after FC. Data were analysed with ANOVA and ROC tests (p < 0.05). Fluid responsiveness was defined as 15% increase in CI. Eighty dogs completed the study. Fifty (62.5%) were responders and 30 (37.5%) were nonresponders. The PPV, PVI, SPV, and SVV cut-off values (AUC, p) for discriminating responders from nonresponders were PPV >13.8% (0.979, <0.001), PVI >14% (0.956, <0.001), SPV >4.1% (0.793, <0.001), and SVV >14.7% (0.729, <0.001), respectively. Up to 62.5% of normotensive dogs under inhalant anaesthesia may be fluid responders. PPV and PVI have better diagnostic accuracy to predict FR, compared to SPV and SVV

Numerical preservation of velocity induced invariant regions for reaction-diffusion systems on evolving surfaces

We propose and analyse a finite element method with mass lumping (LESFEM) for the numerical approximation of reaction-diffusion systems (RDSs) on surfaces in R3 that evolve under a given velocity field. A fully-discrete method based on the implicit-explicit (IMEX) Euler time-discretisation is formulated and dilation rates which act as indicators of the surface evolution are introduced. Under the assumption that the mesh preserves the Delaunay regularity under evolution, we prove a sufficient condition, that depends on the dilation rates, for the existence of invariant regions (i) at the spatially discrete level with no restriction on the mesh size and (ii) at the fully-discrete level under a timestep restriction that depends on the kinetics, only. In the specific case of the linear heat equation, we prove a semi- and a fully-discrete maximum principle. For the well-known activator-depleted and Thomas reaction-diffusion models we prove the existence of a family of rectangles in the phase space that are invariant only under specific growth laws. Two numerical examples are provided to computationally demonstrate (i) the discrete maximum principle and optimal convergence for the heat equation on a linearly growing sphere and (ii) the existence of an invariant region for the LESFEM-IMEX Euler discretisation of a RDS on a logistically growing surface

Tourism and water inequity in Bali: A social-ecological systems analysis

This paper is a social-ecological systems (SES) analysis of tourism and water inequity in Bali. It uses Elinor Ostrom’s SES model to look at the particular niche of Bali’s tourism and water nexus. Re-analysis of previous qualitative research revealed that the vulnerability of the SES was due to numerous characteristics. In particular, user groups are highly diverse, transient and stratified, thereby inhibiting communication and knowledge sharing. This, in combination with weak governance systems and the economic power of the tourism industry, interact to affect declining water resources and the iniquitous impact of this. Whilst there are obvious indications that Bali’s water resources are over stretched, there is no feedback loop to the institutional structures that would help enable appropriate responses from the user groups or governance system

Detection of GD2-positive cells in bone marrow samples and survival of patients with localised neuroblastoma

The impact of bone marrow (BM) GD2-positive cells on survival has been evaluated in 145 Italian children with localised neuroblastoma (NB) evaluated at diagnosis by anti-GD2 immunocytochemistry. Nineteen of these (13.1%) were found to be BM GD2-positive, with the number of positive cells ranging between 1 and 155 out of 1 × 106 total cells analysed. Seven/19 (38.8%) GD2-positive vs 12/126 (9.5%) GD2-negative patients relapsed. The 5-year event-free survival (EFS) and overall survival of the GD2-positive patients was significantly worse than that of the GD2-negative ones (62.2 vs 89.9%, P<0.001; and 74.9 vs 95.9%, P=0.005, respectively). GD2 positivity was not associated to other known risk factors, and in particular to Myc-N amplification and 1p deletion. Among Myc-N-negative patients, the EFS of those negative for both GD2 and 1p deletion was significantly better than in children positive for either one of these two markers (EFS=96.9 vs 66.0%, P<0.001). In conclusion, GD2 positivity may represent a prognostic marker for patients with non-metastatic NB without Myc-N amplification, and its combination with genetic alterations might help identifying patients that require a more careful follow-up

Мова українських обрядових пісень

Intestinal failure (IF) is the reduction in functioning gut mass below the minimal level necessary for adequate digestion and absorption of nutrients and fluids for weight maintenance in adults or for growth in children. There is a paucity of epidemiologic data on pediatric IF. The purpose of this study was to determine the prevalence, incidence, regional distribution and underlying diagnosis of pediatric chronic IF (CIF) requiring home parenteral nutrition (HPN) in Italy. METHODS: Local investigators were selected in 19 Italian centers either of reference for pediatric HPN or having pediatric gastroenterologists or surgeons on staff and already collaborating with the Italian Society for Pediatric Gastroenterology, Hepatology and Nutrition with regard to IF. Data requested in this survey for children at home on Parenteral Nutrition (PN) on 1 December 2016 included patient initials, year of birth, gender, family's place of residence and underlying diagnosis determining IF. RESULTS: We recorded 145 CIF patients on HPN aged ≤19 years. The overall prevalence was 14.12/million inhabitants (95% CI: 9.20-18.93); the overall incidence was 1.41/million inhabitant years (95% CI: 0.53-2.20). CONCLUSION: Our survey provides new epidemiological data on pediatric CIF in Italy; these data may be quantitatively useful in developing IF care strategy plans in all developed countrie