Method for the characterization of Fresnel lens flux transfer performance

Fresnel lenses and other faceted or micro-optic devices are increasingly used in multiple applications like solar light concentrators and illumination devices, just to name some representative. However, it seems to be a certain lack of adequate techniques for the assessment of the performance of final fabricated devices. As applications are more exigent this characterization is a must. We provide a technique to characterize the performance of Fresnel lenses, as light collection devices. The basis for the method is a configuration where a camera images the Fresnel lens aperture. The entrance pupil of the camera is situated at the focal spot or the conjugate of a simulated solar source. In this manner, detailed maps of the performance of different Fresnel lenses are obtained for different acceptance angles.

Resonant elements contactless coupled to bolometric micro-stripes

One of the main technical difficulties in the fabrication of optical antennas working as light detectors is the proper design and manufacture of auxiliary elements as load lines and signal extraction structures. These elements need to be quite small to reach the location of the antennas and should have a minimal effect on the response of the device. Unfortunately this is not an easy task and signal extraction lines resonate along with the antenna producing a complex signal that usually masks the one given by the antenna. In order to decouple the resonance from the transduction we present in this contribution a parametric analysis of the response of a bolometric stripe that is surrounded by resonant dipoles with different geometries and orientations. We have checked that these elements should provide a signal proportional to the polarization state of the incoming light.

Analysis of the spectral response of fractal antennas related with its geometry and current paths

Fractal antennas have been proposed to improve the bandwidth of resonant structures and optical antennas. Their multiband characteristics are of interest in radiofrequency and microwave technologies. In this contribution we link the geometry of the current paths built-in the fractal antenna with the spectral response. We have seen that the actual currents owing through the structure are not limited to the portion of the fractal that should be geometrically linked with the signal. This fact strongly depends on the design of the fractal and how the different scales are arranged within the antenna. Some ideas involving materials that could actively respond to the incoming radiation could be of help to spectrally select the response of the multiband design.

Detectivity comparison of bolometric optical antennas

The practical application of optical antennas in detection devices strongly depends on its ability to produce an acceptable signal-to-noise ratio for the given task. It is known that, due to the intrinsic problems arising from its sub-wavelength dimensions, optical antennas produce very small signals. The quality of these signals depends on the involved transduction mechanism. The contribution of different types of noise should be adapted to the transducer and to the signal extraction regime. Once noise is evaluated and measured, the specific detectivity, D*, becomes the parameter of interest when comparing the performance of antenna coupled devices with other detectors. However, this parameter involves some magnitudes that can be defined in several ways for optical antennas. In this contribution we are interested in the evaluation and comparison of D_ values for several bolometric optical antennas working in the infrared and involving two materials. At the same time, some material and geometrical parameters involved in the definition of noise and detectivity will be discussed to analyze the suitability of D_ to properly account for the performance of optical antennas.

Topographic optical profilometry of steep slope micro-optical transparent surfaces

Optical profilometers based on light reflection may fail at surfaces presenting steep slopes and highly curved features. Missed light, interference and diffraction at steps, peaks and valleys are some of the reasons. Consequently, blind areas or profile artifacts may be observed when using common reflection micro-optical profilometers (confocal, scanning interferometers, etc…). The Topographic Optical Profilometry by Absorption in Fluids (TOPAF) essentially avoids these limitations. In this technique an absorbing fluid fills the gap between a reference surface and the surface to profile. By comparing transmission images at two different spectral bands we obtain a reliable topographic map of the surface. In this contribution we develop a model to obtain the profile under micro-optical observation, where high numerical aperture (NA) objectives are mandatory. We present several analytical and experimental results, validating the technique’s capabilities for profiling steep slopes and highly curved micro-optical surfaces with nanometric height resolution.

Light losses in hollow, prismatic light guides related to prim defects: a transmittance model

Hollow, cylindrical, prismatic light guides (CPLGs) are optical components that, using total internal reflection (TIR), are able to transmit high-diameter light beams in daylight and artificial lighting applications without relevant losses. It is necessary to study the prism defects of their surfaces to quantify the behavior of these optical components. In this Letter, we analyze a CPLG made of a transparent dielectric material. Scanning electron microscopy (SEM) and the topographic optical profilometry by absorption in fluids (TOPAF) imaging technique are conducted to determine if there are defects in the corners of the prisms. A model for light guide transmittance that is dependent on prism defects is proposed. Finally, a simulation and an experimental study are carried out to check the validity of the proposed model.

Entre iusnaturalismo y positivismo: John Finnis

John Finnis, de origen australiano; culminó su formación académica y se desempeñó como profesor en Oxford. Absorbió la filosofía analítica, vigente en el ambiente intelectual y universitario del mundo anglosajón en la segunda mitad del siglo XX. Ante la inquietud de encontrar un fundamento más sólido a los derechos naturales, dentro de la concepción positivista, L.H.A Hart pidió a Finnis que escribiera sobre la ley natural y los derechos naturales. Finnis había realizado su tesis doctoral bajo la dirección de Hart. Después de diez años, en 1980, Finnis publica Natural Law and Natural Rights. Es una obra densa, dirigida principalmente a los teóricos del derecho que ya percibían la insuficiencia del iuspositivismo pero que seguían considerando que las teorías iusnaturalistas carecían de recursos para explicar válidamente el derecho. En Natural Law and Natural Rights, Finnis demuestra lo contrario: que la respuesta adecuada está precisamente en el iusnaturalismo, pero en un iusnaturalismo que ahonda sus raíces en la doctrina de Tomás de Aquino, y no en las concepciones e interpretaciones, a veces, arbitrarias que la escolástico hizo de él. Finnis parte, como lo hacen todos sus contemporáneos, de una perspectiva positivista. Determina a las leyes vigentes como el objeto de su estudio. Pero descubre que ni la sanción, ni la presión social, ni la costumbre u otros motivos aducidos por el positivismo son razones suficientes para que una persona cumpla y observe las disposiciones legales. Lo único que explica cabalmente el cumplimiento de una ley es la racionalidad que ésta implica en razón del bien común. En el análisis de esa racionalidad, Finnis establece: primero, que hay bienes evidentes, en el sentido de que no requieren de ninguna comprobación adicional o más fundamental; que la razón exige que sean actualizados para que la persona se realice. Esos bienes fundamentales (formas básicas en la terminología finnisiana) son: la vida, el conocimiento, el juego, la amistad, la experiencia estética, la razonabilidad práctica y la religión. Lo segundo que Finnis afirma, es que cada uno escoge, como proyecto de vida, uno de estos bienes. Por lo tanto, todas las decisiones en la vida estarán conformadas por esa opción de vida que cada uno ha escogido. No existe primacía de una forma básica sobre otra. No hay jerarquía de valores. La prioridad la da el sujeto, al optar por una de ellas...

Oral vaccination with heat inactivated Mycobacterium bovis activates the complement system to protect against tuberculosis

Tuberculosis (TB) remains a pandemic affecting billions of people worldwide, thus stressing the need for new vaccines. Defining the correlates of vaccine protection is essential to achieve this goal. In this study, we used the wild boar model for mycobacterial infection and TB to characterize the protective mechanisms elicited by a new heat inactivated Mycobacterium bovis vaccine (IV). Oral vaccination with the IV resulted in significantly lower culture and lesion scores, particularly in the thorax, suggesting that the IV might provide a novel vaccine for TB control with special impact on the prevention of pulmonary disease, which is one of the limitations of current vaccines. Oral vaccination with the IV induced an adaptive antibody response and activation of the innate immune response including the complement component C3 and inflammasome. Mycobacterial DNA/RNA was not involved in inflammasome activation but increased C3 production by a still unknown mechanism. The results also suggested a protective mechanism mediated by the activation of IFN-γ producing CD8+ T cells by MHC I antigen presenting dendritic cells (DCs) in response to vaccination with the IV, without a clear role for Th1 CD4+ T cells. These results support a role for DCs in triggering the immune response to the IV through a mechanism similar to the phagocyte response to PAMPs with a central role for C3 in protection against mycobacterial infection. Higher C3 levels may allow increased opsonophagocytosis and effective bacterial clearance, while interfering with CR3-mediated opsonic and nonopsonic phagocytosis of mycobacteria, a process that could be enhanced by specific antibodies against mycobacterial proteins induced by vaccination with the IV. These results suggest that the IV acts through novel mechanisms to protect against TB in wild boar.

Long-term assessment of wild boar harvesting and cattle removal for bovine tuberculosis control in free ranging populations

Wild boar is a recognized reservoir of bovine tuberculosis (TB) in the Mediterranean ecosystems, but information is scarce outside of hotspots in southern Spain. We describe the first high-prevalence focus of TB in a non-managed wild boar population in northern Spain and the result of eight years of TB management. Measures implemented for disease control included the control of the local wild boar population through culling and stamping out of a sympatric infected cattle herd. Post-mortem inspection for detection of tuberculosis-like lesions as well as cultures from selected head and cervical lymph nodes was done in 745 wild boar, 355 Iberian ibexes and five cattle between 2004 and 2012. The seasonal prevalence of TB reached 70% amongst adult wild boar and ten different spoligotypes and 13 MIRU-VNTR profiles were detected, although more than half of the isolates were included in the same clonal complex. Only 11% of infected boars had generalized lesions. None of the ibexes were affected, supporting their irrelevance in the epidemiology of TB. An infected cattle herd grazed the zone where 168 of the 197 infected boars were harvested. Cattle removal and wild boar culling together contributed to a decrease in TB prevalence. The need for holistic, sustained over time, intensive and adapted TB control strategies taking into account the multi-host nature of the disease is highlighted. The potential risk for tuberculosis emergence in wildlife scenarios where the risk is assumed to be low should be addressed.

Splitting of a prevalent Mycobacterium bovis spoligotype by variable-number tandem-repeat typing reveals high heterogeneity in an evolving clonal group

Mycobacterium bovis populations in countries with persistent bovine tuberculosis usually show a prevalent spoligotype with a wide geographical distribution. This study applied mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing to a random panel of 115 M. bovis isolates that are representative of the most frequent spoligotype in the Iberian Peninsula, SB0121. VNTR typing targeted nine loci: ETR-A (alias VNTR2165), ETR-B (VNTR2461), ETR-D (MIRU4, VNTR580), ETR-E (MIRU31, VNTR3192), MIRU26 (VNTR2996), QUB11a (VNTR2163a), QUB11b (VNTR2163b), QUB26 (VNTR4052), and QUB3232 (VNTR3232). We found a high degree of diversity among the studied isolates (discriminatory index [D] = 0.9856), which were split into 65 different MIRU-VNTR types. An alternative short-format MIRU-VNTR typing targeting only the four loci with the highest variability values was found to offer an equivalent discriminatory index. Minimum spanning trees using the MIRU-VNTR data showed the hypothetical evolution of an apparent clonal group. MIRU-VNTR analysis was also applied to the isolates of 176 animals from 15 farms infected by M. bovis SB0121; in 10 farms, the analysis revealed the coexistence of two to five different MIRU types differing in one to six loci, which highlights the frequency of undetected heterogeneity.

Genetic diversity of Mycobacterium avium isolates recovered from clinical samples and from the environment: molecular characterization for diagnostic purposes

Isolation of Mycobacterium avium complex (MAC) organisms from clinical samples may occur in patients without clinical disease, making the interpretation of results difficult. The clinical relevance of MAC isolates from different types of clinical samples (n = 47) from 39 patients in different sections of a hospital was assessed by comparison with environmental isolates (n = 17) from the hospital. Various methods for identification and typing (commercial probes, phenotypic characteristics, PCR for detection of IS1245 and IS901, sequencing of the hsp65 gene, and pulsed-field gel electrophoresis) were evaluated. The same strain was found in all the environmental isolates, 21 out of 23 (91.3%) of the isolates cultured from urine samples, and 5 out of 19 (26.3%) isolates from respiratory specimens. This strain did not cause disease in the patients. Testing best characterized the strain as M. avium subsp. hominissuis, with the unusual feature that 81.4% of these isolates lacked the IS1245 element. Contamination of certain clinical samples with an environmental strain was the most likely event; therefore, characterization of the environmental mycobacteria present in health care facilities should be performed to discard false-positive isolations in nonsterile samples, mainly urine samples. Molecular techniques applied in this study demonstrated their usefulness for this purpose.

3D-form metrology of arbitrary optical surfaces by absorption in fluids

We present an imaging technique for the 3D-form metrology of optical surfaces. It is based on the optical absorption in fluids situated between the surface and a reference. An improved setup with a bi-chromatic light source is fundamental to obtain reliable topographic maps. It is able to measure any surface finish (rough or polished), form and slope and independently of scale. We present results focused on flat and spherical optical surfaces, arrays of lenses and with different surface finish (rough-polished). We achieve form accuracies from several nanometers to sub-lambda for sag departures from tens to hundred of microns. Therefore, it seems suitable for the quality control in the production of precision aspheric, freeform lenses and other complex shapes on transparent substrates, independently of the surface finish.

Perfilómetro tridimensional por absorción óptica en fluídos

El invento permite medir la topografía de superficies pertenecientes a un substrato (22) transparente o traslúcido que deja pasar luz a su través. Frente a la superficie de estudio (221) se acerca otra de referencia (241) de la que se conoce su topografía. El espacio intermedio se rellena con fluido ópticamente absorbente (23) y se ilumina el conjunto con una fuente extensa (15) de la que se pueden diferenciar al menos dos bandas espectrales con absorción diferente en el fluido (23). El cociente de radiancias integradas en esas bandas espectrales no depende del punto de la fuente ni de la dirección de observación. El registro de imágenes (32) de la luz transmitida en esas bandas espectrales y su análisis posterior permite obtener el perfil completo de la superficie de estudio (221).

Variable-spectrum solar simulator

The invention relates to a variable-spectrum solar simulator for characterising photovoltaic systems. The simulator can be used to obtain a spectrum adjusted to the solar spectrum, both for a standard spectrum or a real spectrum adjusted to local irradiation conditions. The simulator also allows the spatial-angular characteristics of the sun to be reproduced. The invention comprises: a broad-spectrum light source, the flux from which is emitted through an aperture; an optical system which collimates the primary source; a system which disperses the beam chromatically; an optical system which forms an image of the dispersed primary source at a given position, at which a spatial mask is placed in order to filter the received irradiance spectrally; an optical system which captures the filtered spectrum and returns, mixes and concentrates same in a secondary source with the desired spectral, angular, and spatial characteristics; an optical system which collimates the secondary source such that it reproduces the angular characteristics of the sun; and a control system.

La restauración del libro Cirugía Universal de Juan Fragoso, impreso en Alcalá de Henares en 1607

En el presente artículo se ofrecen los procedimientos y resultados de la restauración del libro Cirugía Universal (1607) de Juan Fragoso, llevada a cabo por las autoras durante las prácticas curriculares del Título Superior de Conservación y Restauración de Bienes Culturales en la especialidad de Documento Gráfico y durante las prácticas realizadas en el marco de la “Campaña de Verano” 2016 respectivamente, gracias al acuerdo de colaboración entre la Biblioteca Histórica y la Escuela Superior de Conservación y Restauración de Bienes Culturales.