Bifurcations of beam-beam like maps

The bifurcations of a class of mappings including the beam-beam map are examined. These maps are asymptotically linear at infinity where they exhibit invariant curves and elliptic periodic points. The dynamical behaviour is radically different with respect to the Henon-like polynomial maps whose stability boundary (dynamic aperture) is at a finite distance. Rather than the period-doubling bifurcations exhibited by the Henon-like maps, we observe a systematic appearance of tangent bifurcations and in phase space one observes the disappearance of chains of islands born from the origin and coming from infinity. This behaviour has relevant consequences on the transport process

Network organizations of general practitioners: antecedents of formation and consequences of participation

BACKGROUND: Network forms of organization are increasingly popular in primary care. At the end of the 1990s General Practitioners (GPs) in Italy were given the opportunity to adopt network forms of organization with the aim of improving the quality of their services. However factors affecting GPs' choices to join a network and the consequences of network membership have not been evaluated. METHODS: Administrative data of a Local Health Authority in Central Italy were analyzed using statistical methods at individual and dyadic levels of analysis. RESULTS: Homophily factors seem to influence a GP's choice of network. The consequences of network membership on GP performances seem very limited. CONCLUSIONS: When considering to foster the diffusion of network organizational forms in health care creating a network structure, like that of Italian GPs, is not sufficient. Other features of the implementation phase, work organization and human resource management should also be considered

An ecological study on the relationship between supply of beds in long-term care institutions in Italy and potential care needs for the elderly

<p>Abstract</p> <p>Background</p> <p>The ageing population in Europe is putting an ever increasing demand on the long-term care (LTC) services provided by these countries. This study analyses the relationship between the LTC institutional supply of beds and potential care needs, taking into account the social and health context, the supply of complementary and alternative services, along with informal care.</p> <p>Methods</p> <p>An observational, cross-sectional, ecological study was carried out. Statistical data were obtained from the Italian National Institute of Statistics and Ministry of Health. Indicators, regarding 5 areas (Supply of beds in long term care institutions, Potential care needs, Social and health context, Complementary and alternative services for the elderly, Informal care), were calculated at Local Health Unit (LHU) level and referred to 2004.</p> <p>Two indicators were specifically used to measure supply of beds in long term care institutions and potential care needs for the elderly. Their values were grouped in tertiles. LHU were classified according to the combination of tertiles in three groups: A. High level of supply of beds in long term care institutions associated with low level of potential care needs; B. Low level of supply of beds in long term care institutions associated with high level of potential care needs; C. Balanced level of supply of beds in long term care institutions with potential care needs. For each group the indicators of 5 areas were analysed.</p> <p>The Index Number (IN) was calculated for each of these indicators.</p> <p>Results</p> <p>Specific factors that need to be carefully considered were highlighted in each of the three defined groups. The highest level of alternative services such as long-stay hospital discharges in residence region (IN = 125), home care recipients (HCR) (IN = 123.8) were reported for Group A. This group included North regions. The highest level of inappropriate hospital discharges in (IN = 124.1) and out (IN = 155.8) the residence region, the highest value of families who received help (IN = 106.4) and the lowest level of HCR (IN = 68.7) were found in Group B. South regions belong to this group. The highest level of families paying a caregiver (IN = 115.8) was shown in Group C. Central regions are included in third group.</p> <p>Conclusion</p> <p>Supply of beds in long term care institutions substantially differs across Italian regions, showing in every scenario some imbalances between potential care needs and other studied factors. Our study suggests the need of a comprehensive rethinking of care delivery "system".</p

Euclid, Geometry and Nature

A pedagogical treatment is given on how the euclidean geometry can be used to describe complex and fractal shapes found in nature

Explosive percolation in correlation-based networks

In the field of network theory, the so called \u201cexplosive percolation\u201d phenomenon has recently raised great interest, in which a giant cluster transition is obtained by the addition of a negligibly small number of links (as opposed to erdos-renyi classical random networks). We describe a similar behaviour in networks obtained from a correlation matrix of randomly generated vectors, both in the limit of high correlation and anti-correlation. This phenomenon is relevant in many practical applications, from financial to high-throughput genomic data analysis, in which time correlation is widely applied to characterize the global and local dynamics of the system

A quantitative bifurcation analysis of Hénon-like 2D maps

We numerically study the bifurcations of two nonlinear maps, with the same linear part, which depend on a parameter namely the Hénon quadratic map and the so called &apos;beam-beam&apos; map. Many families of periodic orbits which bifurcate from the central family, are studied. Each family undergoes a sequence of period doubling bifurcations in the quadratic map. But the behavior of the &apos;beam-beam&apos; map is completely different. Inverse bifurcations occur in both maps. But some families of the same type which bifurcate inversely in the quadratic map do not bifurcate inversely in the &apos;beam-beam&apos; map, even though both maps have common linear part. © 1997 Kluwer Academic Publishers