1,795 research outputs found
Unpredictability in seasonal infectious diseases spread
In this work, we study the unpredictability of seasonal infectious diseases
considering a SEIRS model with seasonal forcing. To investigate the dynamical
behaviour, we compute bifurcation diagrams type hysteresis and their respective
Lyapunov exponents. Our results from bifurcations and the largest Lyapunov
exponent show bistable dynamics for all the parameters of the model. Choosing
the inverse of latent period as control parameter, over 70% of the interval
comprises the coexistence of periodic and chaotic attractors, bistable
dynamics. Despite the competition between these attractors, the chaotic ones
are preferred. The bistability occurs in two wide regions. One of these regions
is limited by periodic attractors, while periodic and chaotic attractors bound
the other. As the boundary of the second bistable region is composed of
periodic and chaotic attractors, it is possible to interpret these critical
points as tipping points. In other words, depending on the latent period, a
periodic attractor (predictability) can evolve to a chaotic attractor
(unpredictability). Therefore, we show that unpredictability is associated with
bistable dynamics preferably chaotic, and, furthermore, there is a tipping
point associated with unpredictable dynamics
Mucopolysaccharidosis I, II, and VI: Brief review and guidelines for treatment
Mucopolysaccharidoses (MPS) are rare genetic diseases caused by the deficiency of one of the lysosomal enzymes involved in the glycosaminoglycan (GAG) breakdown pathway. This metabolic block leads to the accumulation of GAG in various organs and tissues of the affected patients, resulting in a multisystemic clinical picture, sometimes including cognitive impairment. Until the beginning of the XXI century, treatment was mainly supportive. Bone marrow transplantation improved the natural course of the disease in some types of MPS, but the morbidity and mortality restricted its use to selected cases. The identification of the genes involved, the new molecular biology tools and the availability of animal models made it possible to develop specific enzyme replacement therapies (ERT) for these diseases. At present, a great number of Brazilian medical centers from all regions of the country have experience with ERT for MPS I, II, and VI, acquired not only through patient treatment but also in clinical trials. Taking the three types of MPS together, over 200 patients have been treated with ERT in our country. This document summarizes the experience of the professionals involved, along with the data available in the international literature, bringing together and harmonizing the information available on the management of these severe and progressive diseases, thus disclosing new prospects for Brazilian patients affected by these conditions
- …