Migration rate estimation in an epidemic network.

Most of the recent epidemic outbreaks in the world have as a trigger, a strong migratory component as has been evident in the recent Covid-19 pandemic. In this work we address the problem of migration of human populations and its effect on pathogen reinfections in the case of Dengue, using a Markov-chain susceptible-infected-susceptible (SIS) metapopulation model over a network. Our model postulates a general contact rate that represents a local measure of several factors: the population size of infected hosts that arrive at a given location as a function of total population size, the current incidence at neighboring locations, and the connectivity of the network where the disease spreads. This parameter can be interpreted as an indicator of outbreak risk at a given location. This parameter is tied to the fraction of individuals that move across boundaries (migration). To illustrate our model capabilities, we estimate from epidemic Dengue data in Mexico the dynamics of migration at a regional scale incorporating climate variability represented by an index based on precipitation data.

Turing instability conditions in confined systems with an effective position-dependent diffusion coefficient.

We study a reaction-diffusion system within a long channel in the regime in which the projected Fick-Jacobs-Zwanzig operator for confined diffusion can be used. We found that under this approximation, Turing instability conditions can be modified due to the channel geometry. The dispersion relation, range of unstable modes where pattern formation occurs, and spatial structure of the patterns itself change as functions of the geometric parameters of the channel. This occurs for the three channels analyzed, for which the values of the projected operators can be found analytically. For the reaction term, we use the well-known Schnakenberg kinetics.

Specimen preparation for "block face" scanning electron microscopy (BFSEM). An energy-dispersive X-ray spectroscopy study

In this paper we describe a SEM block-face technique in which block faces of large dimensions can be examined in a high-resolution SEM under high vacuum. The results of different tissue contrast methods have been studied and, in addition to osmium, potassium permanganate has been used as a staining medium for the first time in BFSEM. The study also examined the effects of uranyl acetate and phosphotungstic acid. The following organs of adult albino rats were examined: colonic mucosa, spinal ganglion, anterior pituitary gland and exocrine pancreas.Six preparation protocols, referred to here as treatments, were applied and evaluated according to three criteria: 1st the visual quality of the digital images, 2nd the measurements of the signal-noise ratio (SNR) of the digital images with and without beam deceleration (BD), and 3rd the X-ray microanalysis of samples, treated according to the 6 proposed protocols, demonstrating the presence and relative quantity of the elements used to stain the cellular structures, enabling visualisation with the electron microscope. In conclusion, it can be said that treatments with osmium produced better results than those containing potassium permanganate. Treatments with the addition of thiocarbohydrazide (TCH) considerably increased the osmium deposits (ligand effect) and proved highly effective. Finally, it should be noted that the method proposed, called here 2D BFSEM, can be very useful not only in histology but also in histo-pathology, for example in the study of biopsies and - last but not least - in embryology: all these are situations in which it is important to avoid a loss of material due to preparation exigencies

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Self-similar Turing patterns: An anomalous diffusion consequence.

In this work, we show that under specific anomalous diffusion conditions, chemical systems can produce well-ordered self-similar concentration patterns through diffusion-driven instability. We also find spiral patterns and patterns with mixtures of rotational symmetries. The type of anomalous diffusion discussed in this work, either subdiffusion or superdiffusion, is a consequence of the medium heterogeneity, and it is modeled through a space-dependent diffusion coefficient with a power-law functional form.

Transmission dynamics of two dengue serotypes with vaccination scenarios.

In this work we present a mathematical model that incorporates two Dengue serotypes. The model has been constructed to study both the epidemiological trends of the disease and conditions that allow coexistence in competing strains under vaccination. We consider two viral strains and temporary cross-immunity with one vector mosquito population. Results suggest that vaccination scenarios will not only reduce disease incidence but will also modify the transmission dynamics. Indeed, vaccination and cross immunity period are seen to decrease the frequency and magnitude of outbreaks but in a differentiated manner with specific effects depending upon the interaction vaccine and strain type.

[Limits of therapeutic effort. Professional opinions]. / Limitación del esfuerzo terapéutico. Opinión de los profesionales.

INTRODUCTION: In our clinical practice we find the need to care for patients with irreversible conditions, due to advanced age or underlying chronic disease, and a change in the types of disease currently facing the health workforce.The objective of this research was to study the ethical assessment of health professionals in our Hospital on extraordinary life support measures. MATERIAL AND METHODS: Prospective descriptive study conducted at the Hospital General Universitario de Ciudad Real during the months of April to August 2010. The convenience sample consisted of 189 professionals from different categories working in our hospital during the study period.It included a questionnaire adapted for use in hospitals, comprising 18 items with dichotomous responses.Informed consent was requested and the confidentiality of information ensured. RESULTS: A sample of 189 professionals, of whom 21.7% were male and 78.3% were female. The mean age was 40.39 years SD + 10, with a mode of 31 years.The professionals involved were doctors, nurses and nursing assistants, with an average experience of 15.8% ± 10.4 SD years.A total of 79.9% were in favour of euthanasia, 93.6% against dysthanasia, 92.6% for antidysthanasia, and 99.5% for orthotonasia. The medical group was the one most against the use of euthanasia P=.0001. Differences were found between religious practice and the ethical situations at the end of life. CONCLUSIONS: Most participants took into account the patient's decision to limit extraordinary measures in terminal disease situations.The study reveals that the effectiveness and usefulness of our clinical practice should include an ethical evaluation by professionals with the patient. It became clear that the majority of the sample of professionals is against over-aggressive treatment, and for a dignified death.