Estudio del flujo de energía en un cristal fotónico unidimensional aperiódico compuesto por materiales polímeros

En este trabajo se determin´o el comportamiento de la radiaci´on electromagn´etica para un cuasicristal fot´onico unidimensionalorganizado por una sucesi´on de Fibonacci con polarizaci´on TE (Transversal El´ectrica) y TM (Transversal Magn´etica) para diferentes ´angulos de incidencia. Un cristal fot´onico se clasifica como cuasiperi´odico cuando posee una estructura ordenada y una aperi´ocidad en su ´ındice de refracción. Sus capas se alternan siguiendo una regla recursiva de Fibonacci para materiales polímeros: PS (poliestireno) y PMMA (polimetacrilato de metilo). El comportamiento de la radiación se registra a través de un espectro de transmitancia calculado por el MMT (M´etodo de la Matriz de Transferencia). Se evidencio la presencia de BBFs (Brechas de Banda Fot´onica) las cuales, se controlaron variando parámetros como: la secuencia de Fibonacci, el ´ángulo de incidencia de la luz y el grosor de las capas delos materiales. Se encontró que al aumentar el ´angulo de incidencia de la onda electromagnética sobre el cuasicristal observamos un corrimiento de la BBF (Brechas de Banda Fotónica) hacia frecuencias altas. Además, se comprueba que al incrementar la secuencia de Fibonacci el n´umero de gaps presentes en el espectro de transmisión aumenta, al igual que el número de capas en la estructura. Por otra parte, se demostr´o que la polarizaci´on TM (Transversal Magnética) presenta un mayor número de gaps con valores menores en la transmitancia. Finalmente, al aumentar el grosor de las capas de los materiales, con presión y secuencia constante las BBFs (Brechas de Banda Fot´onica) muestran un corrimiento hacia frecuencias bajas para ambas polarizaciones (TE y TM)

State–Space Forecasting of Schistosoma haematobium Time-Series in Niono, Mali

Adequate forecasting and early warning systems are based upon observations of human behavior, population, disease time-series, climate, environment, and/or a combination thereof, whichever option best compromises among realism, feasibility, robustness, and parsimony. Fully automatic and user-friendly state–space forecasting frameworks, incorporating myriad options (e.g., expert opinion, univariate, multivariate, and spatial-temporal), could considerably enhance disease control and hazard mitigation efforts in regions where vulnerability to neglected tropical diseases is pervasive and statistical expertise is scarce. The operational simplicity, generality, and flexibility of state–space frameworks, encapsulating multiple methods, could conveniently allow for 1) unsupervised model selection without disease-specific methodological tailoring, 2) on-line adaptation to disease time-series fluctuations, and 3) automatic switches between distinct forecasting methods as new time-series perturbations dictate. In this investigation, a univariate state–space framework with the aforementioned properties was successfully applied to the Schistosoma haematobium time-series for the district of Niono, Mali, to automatically generate contemporaneous on-line forecasts and hence, providing a basis for local re-organization and strengthening public health programs in this and potentially other Sahelian districts

Assessing the effects of multiple infections and long latency in the dynamics of tuberculosis

In order to achieve a better understanding of multiple infections and long latency in the dynamics of Mycobacterium tuberculosis infection, we analyze a simple model. Since backward bifurcation is well documented in the literature with respect to the model we are considering, our aim is to illustrate this behavior in terms of the range of variations of the model's parameters. We show that backward bifurcation disappears (and forward bifurcation occurs) if: (a) the latent period is shortened below a critical value; and (b) the rates of super-infection and re-infection are decreased. This result shows that among immunosuppressed individuals, super-infection and/or changes in the latent period could act to facilitate the onset of tuberculosis. When we decrease the incubation period below the critical value, we obtain the curve of the incidence of tuberculosis following forward bifurcation; however, this curve envelops that obtained from the backward bifurcation diagram

Effectiveness and safety of generic version of abacavir/lamivudine and efavirenz in treatment naive HIV-infected patients: a nonrandomized, open-label, phase IV study in Cali-Colombia, 2011-2012

Background: Generic drug policies are often associated with concerns about the quality and effectiveness of these products. Phase IV clinical trials may be a suitable design to assess the effectiveness and safety of generic drugs. The objective of this study was to describe the effectiveness and the safety of the generic abacavir/lamivudine and efavirenz in treatment-naïve HIV-infected patients. Methods: A monocentric, nonrandomized, open-label, phase IV study in treatment naïve HIV-infected patients 18 years or older with indication to receive abacavir/lamivudine and efavirenz were recruited from a program that provides comprehensive outpatient consultation and continuing care. The primary end-point was to achieve viral load <40 copies/mL at 12 months after baseline to assess effectiveness. Secondary end-point of the study were 1) to asses increasing in T-CD4 lymphocytes levels as accompaniment to asses effectiveness, and 2) to assess both gastrointestinal, skin, and central nervous system symptoms, and lipid profile, cardiovascular risk, renal, and hepatic function as safety profile. Data were determined at baseline, 3, 6, and 12 months. Close clinical monitoring and pharmaceutical care were used for data collection. Wilcoxon matched-pairs signed-rank test was used to compare proportions or medians. Results: Sixty patients were invited to participate in the study; 42 were enrolled and 33 completed the follow-up. Of the nine patients excluded from the study, only one was withdrawn due to adverse events. At 12 months, 31 of 42 patients (73.8 % in intention-to-treat analysis) achieved a viral load of HIV1 RNA <40 copies/mL. There was a significant increase (172 cells/mm3) in the median for CD4 T lymphocyte count. The adverse events were mild and met the safety profile for this antiretroviral regimen, mainly of central nervous system symptoms, skin rash, lipid abnormalities, and an increase of 2 % in the median of the percentage of cardiovascular risk. Conclusions: The clinical outcomes of generic version of abacavir/lamivudine and efavirenz in HIV treatment naïve patients showed the expected safety and effectiveness profile of proprietary ARV drugs. Trial registration: Registro Público Cubano de Ensayos Clínicos (RPCEC) ID: RPCEC00000202. Registered 19 November 2015.This research was made possible by contribution from the Corporación de Lucha Contra el SIDA, Cali-Colombia, and Comité para el Desarrollo de la Investigación (CODI), Universidad de Antioquia, Medellín, Colombia. In addition, Humax Pharmaceutical S.A. provided the antiretroviral drugs