Optimization for maximum modulation of a double-pass twisted nematic liquid crystal display.

Spatial light modulators are widely used to perform modulations of different properties of the electromagnetic field. In this work, a simple optimization method for general double-pass setups was developed. It takes into account the involved polarizing elements and displays, and a numerical simulation based on an exhaustive search routine finds the optimal optical axis orientations of the polarizing elements for the desired modulation. By simultaneously considering both impingements, we are able to take full advantage of the modulation capabilities of the chosen spatial light modulators. In particular, different polarization modulations and complex amplitude modulations were studied for twisted nematic liquid crystal displays and passive linear optical elements. Examples of different optimization criteria are shown and compared with experimental results, supporting the feasibility of this approach. This method offers the possibility of independent modulation of two properties of the input light state, outperforming the use of a single screen.

Set of 4d-3 observables to determine any pure qudit state.

We present a tomographic method which requires only 4d-3 measurement outcomes to reconstruct any pure quantum state of arbitrary dimension d. Using the proposed scheme, we have experimentally reconstructed a large number of pure states of dimension d=7, obtaining a mean fidelity of 0.94. Moreover, we performed numerical simulations of the reconstruction process, verifying the feasibility of the method for higher dimensions. In addition, the a priori assumption of purity can be certified within the same set of measurements, which represents an improvement with respect to other similar methods and contributes to answering the question of how many observables are needed to uniquely determine any pure state.

Symmetry properties with pupil phase-filters.

Pupil filters can modify the three dimensional response of an optical system. In this paper, we study different pupil symmetries that produce a predictable image behavior. We show that different pupil-filters that satisfy certain symmetry conditions can produce axial responses which are either identical or mirror reflected. We also establish the differences in the symmetry properties between amplitude-only filters and phase-only filters. In particular, we are interested in phase filters that produce transverse superresolution with axial superresolution or high depth of focus.

Prospective applicability study of the new dengue classification system for clinical management in children.

BACKGROUND: To evaluate the efficacy of the 2009 revised dengue classification system proposed by the World Health Organization (WHO) for early detection of dengue cases requiring intervention. METHODS: Children <15 years of age with dengue [confirmed by laboratory testing (IgM enzyme-linked immunosorbent assay, NS1 Ag or reverse transcriptase polymerase chain reaction) or by epidemiologic link] who were admitted to the Institute of Tropical Medicine during the 2011 dengue outbreak in Paraguay were prospectively included. Each case was classified according to the 1997 WHO dengue criteria and by the 2009 WHO revised criteria, which categorize dengue patients using a set of clinical finding into dengue with/without warning signs and severe dengue. The management of all cases followed the new recommendations. RESULTS: During the 2011 dengue outbreak, 123 children were admitted with a mean age of 11 ± 3 years. By the 2009 classification system, 119 cases (97%) were classified as dengue requiring intervention [89 patients (75%) with warning signs and 30 patients (25%) with severe signs], whereas by the old system 67 patients (54%) were classified as dengue requiring intervention (P < 0.001). Further, by the 1997 classification, only 13 patients (10%) were classified as dengue hemorrhagic fever III/IV (severe cases), whereas with the 2009 classification 30 patients (24%) were considered as having severe dengue infection (P < 0.05) CONCLUSIONS:: This study confirms that the 2009 WHO dengue classification provides better detection of severe cases of dengue than the earlier 1997 WHO dengue system.

Incremento de la severidad del dengue en niños en epidemias sucesivas in Paraguay

Introducción: La expresión clínica de la infección por el virus del dengue (DENV) varía desde formas leves a graves, cuyo predominio puede variar en cada epidemia. Objetivo: Caracterizar el comportamiento clínico del dengue en niños hospitalizados en un centro de referencia del Paraguay, durante los brotes (2007, 2009-10 y 2011). Materiales y métodos: Estudio descriptivo, retrospectivo (años 2007-2009) y prospectivo (2011) basado en la revisión de las historias clínicas de pacientes (pts) internados en el Instituto de Medicina Tropical (IMT) con diagnóstico de egreso de dengue confirmado por laboratorio (IgM Elisa, NS1, RT-PCR) o nexo epidemiológico. Se analizaron y compararon datos demográficos, clínicos, laboratoriales y las complicaciones. Resultados: Se hospitalizaron 270 niños con diagnóstico de dengue, correspondiendo 98 pts (36%) al brote del 2007, 49 pts (18%) al brote de 2009-10 y 123 pts (46%) al brote de 2011. Los serotipos predominantes por periodo fueron DENV-3, DENV-1 y DENV-2 respectivamente. No hubo diferencia significativa en cuanto a la edad de los pacientes por periodo (13 ± 3 años, 12,5 ± 3,6 años y 11 ± 3 años, respectivamente). La incidencia de complicaciones viscerales (encefalitis/miocarditis/hepatitis) fueron mayores en los brotes 2011 (54/123, 44%) y 2.007 (24/98, 24%) respecto al 2009-10 (5/49,10%) (p <0,01), así como la frecuencia de hemorragia severa [18/123 pts (14,6%) en 2011 vs 1/49 (2%) en 2009/10, p <0,05] y la trombocitopenia <50000 (29% en el 2011 vs 12% en 2009/10, p <0,05). La mortalidad fue baja en los tres periodos (1%, 2% y el 1,6%). Conclusiones: La presente serie revela las características particulares de cada brote en relación a la severidad. Durante la circulación del DENV-3 y DENV-2 se observó mayor frecuencia de casos graves incluyendo mayor afectación visceral.

Abstract Introduction: The clinical expression of infection with dengue virus (DENV) varies from mild to severe, the prevalence vary epidemic. Objective: To characterize the clinical behavior of dengue in children hospitalized in a referral center of Paraguay, during outbreaks (2007, 2009-10 and 2011). Materials and Methods: A descriptive, retrospective study based on a review of medical records of patients (pts) hospitalized at the Institute of Tropical Medicine (IMT) with discharge diagnosis of dengue confirmed (2007-2009) and prospective (2011) by lab (IgM Elisa, NS1, RT-PCR) or epidemiological link. They were analyzed and compared demographic, clinical, laboratory data and complications. Results: 270 children were hospitalized with a diagnosis of dengue, corresponding 98 pts (36%) of the 2007 outbreak, 49 pts (18%) the outbreak of 2009-10 and 123 pts (46%) outbreak of 2011. The predominant serotypes by period were DENV-3, DENV-1 and DENV-2 respectively. There was no significant difference in age of patients per period (13 ± 3 years, 12.5 ± 3.6 years and 11 ± 3 years, respectively). The incidence of visceral complications (encephalitis / myocarditis / hepatitis) were higher in 2011 outbreaks (54/123, 44%) and 2,007 (24/98, 24%) compared to 2009-10 (5 / 49,10%) (p <0.01), and the frequency of severe bleeding [18/123 pts (14.6%) in 2011 vs. 1/49 (2%) in 2009/10, p <0.05] and thrombocytopenia < 50000 (29% in 2011 vs. 12% in 2009/10, p <0.05). Mortality was low in all three periods (1%, 2% and 1.6%). Conclusions: This series reveals the particular characteristics of each sprout in relation to the severity. During the circulation of DENV-3 and DENV-2 more frequently more severe cases including visceral involvement it was observed.

Improved expressions for performance parameters for complex filters.

Improved expressions are given for the performance parameters for transverse and axial gains for complex pupil filters. These expressions can be used to predict the behavior of filters that give a small axial shift in the focal intensity maximum and also predict the changes in gain for different observation planes.

Direct visualization of surface-plasmon bandgaps in the diffuse background of metallic gratings.

When a surface plasmon propagates along a microrough grating, it interacts with the periodic plus the random roughness and emits light into the diffuse background, which can present intensity maxima called diffuse light bands. We reexamine previous studies on these bands within the framework of recent studies on photonic surfaces and show that the phenomenon of diffuse light provides an experimental technique for directly imaging the dispersion relation of surface plasmons, including the gap that, under appropriate circumstances, opens in the reciprocal grating space.

Simple expressions for performance parameters of complex filters, with applications to super-Gaussian phase filters.

To study the three-dimensional (3-D) behavior produced by complex filters, we have extended the expressions for the axial and the transverse gain to the case in which the best image plane is not near the paraxial focus. Super-Gaussian phase filters are proposed to control the 3-D image response of an optical system. Super-Gaussian phase filters depend on several parameters that modify the shape of the phase filter, producing tunable control of the 3-D response of the optical system. The filters are capable of producing a wide range of optical effects: transverse superresolution with high depth of focus, 3-D superresolution, and transverse apodization with different axial responses.

Siringomas eruptivos / Eruptive syringomas

Se presentan tres casos de siringomas eruptivos (tipo Jacquet-Darier). En dos de ellos las lesiones aparecieron en brotes sucesivos en la infancia y en el tercero lo hicieron a una edad más tardía. En todos los casos la histología muestra un cuadro característico de siringomas. Se revisan las características clínicas, histopatológicas, diagnósticos diferenciales y tratamiento de una patología poco común en la práctica diaria