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14 Pág. INIA, For understanding the molecular events underlying the follicular (F) and luteal (L) phases of estrous cycle, and anestrous (A) phase, the pars tuberalis (PT), and hypothalamus (HT) transcriptomes of 21 ewes were studied. In HT, 72 and 3 differential expression genes (DEGs) were found when comparing F vs. A and L vs. A, respectively. In PT, 6 and 4 DEGs were found in F vs. A and L vs. A comparisons, respectively. Enrichment analysis for DEGs between the F and A phases in the HT revealed significant clusters, mainly associated with actin-binding, and cytoskeleton, that are related to neural plasticity modulated by gonadal steroid hormones, as well as with oxytocin signaling. We found that DEGs in PT had higher differences in expression levels than those found in HT. In this sense, the ITLN was highly upregulated in the F and L vs. A phases, being MRPL57 and IRX4 highly downregulated in L vs. A comparison. The DDC gene in PT, related to LH regulation, was upregulated in the F phase. The gene set enrichment analysis (GSEA) revealed multiple pathways related to neurotransmission and neuronal plasticity. Our study reveals new candidate genes involved in the reproductive stages' transitions in seasonal sheep., K. Lakhssassi is supported by doctoral grant from the Ministry of Education and Science of Spain. This study was partially financed by the Ministry of Education and Science of Spain research projects INIA-RTA2013-00041-C02 and INIA-RTA2015-0090-C03, and the European Union Regional Development funds; and the Research Group Funds of the Aragón Government (Grupo SAGAS Ref. A14_20R).

Reproductive fitness of rams is seasonal, showing the highest libido during short days coinciding with the ovarian cyclicity resumption in the ewe. However, the remarkable variation in sexual behavior between rams impair farm efficiency and profitability. Intending to identify in vivo sexual behavior biomarkers that may aid farmers to select active rams, transcriptome profiling of blood was carried out by analyzing samples from 6 sexually active (A) and 6 nonactive (NA) Rasa Aragonesa rams using RNA-Seq technique. A total of 14,078 genes were expressed in blood but only four genes were differentially expressed (FDR 1) in active rams, whereas the CRYL1 and immunoglobulin lambda-1 light chain isoform X47 (ENSOARG00020025518) genes were downregulated (log2FC

For understanding the molecular events underlying the follicular (F) and luteal (L) phases of estrous cycle, and anestrous (A) phase, the

Reproductive seasonality is a limiting factor in sheep production. Sexual behavior is a key element in reproductive efficiency, and this function is regulated by the hypothalamus-pituitary-gonadal (HPG) axis. To understand the mechanisms of sexual behavior, transcriptomic sequencing technology was used to identify differentially expressed genes (DEGs) in the hypothalamus (HT), pars tuberalis (PT) and pineal gland (PG) in Rasa Aragonesa rams with different sexual behavior. Bioinformatics analysis of the 16,401 identified genes by RNA-Seq revealed 103 and 12 DEGs in the HT and the PG, respectively, at a false discovery rate (FDR) of 5% with an absolute value of expression ≥ 1 (log2FC). However, no DEGs were found in the PT. Functional annotation and pathway enrichment analysis showed that DEGs of HT were enriched mainly in neuroactive ligand-receptor interactions and signaling pathways, including notable candidate genes such as MTNR1A, CHRNA2, FSHB, LHB, GNRHR, AVP, PRL, PDYN, CGA, GABRD, and TSHB, which play a crucial role in sexual behavior. The GnRH and cAMP signaling pathways were also highlighted. In addition, gene set enrichment analysis (GSEA) identified potential pathways, dominated mainly by biological process category, that could be responsible for the differences in sexual behavior observed in rams. The intracellular protein transport and pattern specification process were enriched within the PT and the transcription factor binding and protein ubiquitination pathways for the PG. Thus, these pathways together may play an important role in the regulation of the sexual behavior in Rasa Aragonesa rams through the hypothalamic-pituitary-gonadal axis. The validation of 5 DEGs using reverse transcription quantitative polymerase chain reaction (RT-qPCR) showed expression patterns like the found with RNA-Seq. Overall, these results contribute to understanding the genomic basis of sexual behavior in rams. Our study demonstrates that multiple networks and pathways orchestrate sexual behavior in sheep.

El objetivo de este trabajo es profundizar en el conocimiento de la sostenibilidad de la producción ovina de carne en Aragón. Para ello se ha analizado una muestra de 37 explotaciones diferenciadas en 3 sistemas productivos en función de las características agronómicas de su finca agrícola y de la disponibilidad de recursos pastorales (Secano, Mixto Secano/Regadío y Montaña). Se han analizado indicadores económicos, sociales y ambientales, y la información obtenida a través de la realización de procesos participativos (focus groups) con diferentes agentes implicados en esta actividad: ganaderos, técnicos y representantes de la población rural (alcaldes y concejales). Los resultados han demostrado que las ganaderías analizadas son sostenibles ambientalmente, pero se encuentran al límite de su sostenibilidad económica y social. El sistema Mixto Secano/Regadío presenta la mayor sostenibilidad económica y el sistema Montaña la mayor sostenibilidad ambiental. Estos resultados contribuyen a mejorar el conocimiento de los diferentes retos a los que se enfrenta el sector ovino, a predecir su evolución en el futuro y pueden contribuir al diseño de políticas que aseguren la continuidad de los sistemas más sostenibles. The aim of this work was to perform a comprehensive assessment of sustainability of sheep meat production in Aragon. For this purpose, a sample of 37 farms differentiated into 3 production systems based on their agronomic characteristics and the availability of pastoral resources (Rainfed, Mixed Rainfed/Irrigated, and Mountain) was analyzed. Economic, social and environmental indicators, as well as the information obtained through a participatory process (focus groups) with different actors involved in this production: farmers, technicians and representatives of the rural population (mayors and councilors) were used. The results showed that the studied farms are environmentally sustainable, but they are at the limit of their economic and social sustainability. The Mixed Rainfed/Irrigation system presents the greatest economic sustainability and the Mountain system the greatest environmental sustainability. These results contribute to improve knowledge of challenges faced by sheep meat systems, to predict its evolution in future, and can contribute to the design of policies that ensure the continuity of the most sustainable ones. Published

Simple Summary Seasonality of reproduction is one of the limiting factor of sheep production, with the leptin receptor (LEPR) gene associated with some reproductive traits in different species. Thereby, we searched for polymorphisms in the ovine LEPR gene and associated them with three reproductive seasonality traits: the total days of anoestrous (TDA) and the progesterone cycling months (P4CM), both based on blood progesterone level and related to seasonal ovarian function; and the oestrous cycling months (OCM) as an indicator of oestrous behaviour. Two non-synonymous and non-linked single nucleotide polymorphisms (SNPs) in the LEPR gene were involved in the OCM trait (rs403578195 and rs405459906). These findings show for the first time the involvement of LEPR gene in seasonality reproduction in sheep and will help to improve genetic selection programs by implementing the genotyping of reproducers, which might increase the productivity of meat sheep. Abstract The aim of this study was to characterize and identify causative polymorphisms in the leptin receptor (LEPR) gene responsible for the seasonal variation of reproductive traits in sheep. Three reproductive seasonality traits were studied: the total days of anoestrous (TDA), the progesterone cycling months (P4CM) and the oestrous cycling months (OCM). In total, 18 SNPs were detected in 33 ewes with extreme values for TDA and OCM. Six SNPs were non-synonymous substitutions and two of them were predicted in silico as deleterious: rs596133197 and rs403578195. These polymorphisms were then validated in 239 ewes. The SNP rs403578195, located in exon 8 and leading to a change of alanine to glycine (Ala284Gly) in the extracellular domain of the protein, was associated with the OCM trait, being the G allele associated with a decrease of 12 percent of the OCM trait. Haplotype analyses also suggested the involvement of other non-synonymous SNP located in exon 20 (rs405459906). This SNP also produces an amino acid change (Lys1069Glu) in the intracellular domain of the protein and segregates independently of rs403578195. These results confirm for the first time the role of the LEPR gene in sheep reproductive seasonality.

A FecX-mutated allele called FecX

The aim of this study was to evaluate the effect of rosemary essential oils (REO) and the forage nature on ewes' performances, immune response and lambs' growth and mortality. Forty-eight dairy ewes (Sicilo-Sarde) were fed oat-hay or oat-silage supplemented with 400 g of concentrate during pregnancy and 600 g during postpartum. The experimental concentrate contained the same mixture as the control (barley, soybean meal and mineral vitamin supplement) more 0.6 g/kg of REO. Two groups were obtained with each forage (Hay groups: H-C and H-REO; Silage groups: S-C and S-REO). REO increased the dry matter (DM) intake, the nitrogen intake and retention being higher with the silage groups (P

En ovino, los retrasos en la edad al primer parto dan lugar a una disminución de la vida productiva del animal, lo que genera importantes pérdidas económicas. En corderas de raza Rasa Aragonesa de 3 meses estimuladas con eCG se ha observado una relación entre la concentración de la hormona Anti-Mülleriana (AMH) y la respuesta ovulatoria con su fertilidad temprana. El objetivo de este trabajo fue relacionar ambos parámetros con la vida productiva de esas corderas (n=73) con AMH ALTA (>=97 pg/ml) o BAJA (=97 pg/ml) or LOW (

espanolLos efectos del gen BMP15, localizado en el cromosoma X, sobre la media y la variabilidad de la prolificidad fueron estimados en la poblacion Rasa Aragonesa, donde se analizaron 918.956 partos de ovejas de distintos genotipos (heterocigotas para el alelo FecXR o ROA®; y no portadoras). En primer lugar, se utilizaron modelos umbral que incluian o no el efecto del gen para estimar el efecto del genotipo BMP15 y su contribucion a la variabilidad genetica de la prolificidad en esta poblacion. Tambien se utilizaron otros dos modelos para estimar las interacciones entre el genotipo y los poligenes, asi como el efecto del genotipo sobre la variabilidad de la prolificidad. Todos los analisis se hicieron con el programa ASReml. El efecto del genotipo sobre la media fue de 0,32 corderos adicionales por parto cuando el alelo ROA® se encontraba presente. Debido a que durante muchos anos la seleccion por prolificidad en esta poblacion se ha llevado a cabo desconociendo la presencia de esta mutacion, los animales selectos portadores tienen un valor genetico poligenico residual mas bajo que los no portadores. No se encontro interaccion significativa entre el genotipo y los efectos poligenicos sobre el valor genetico. Aunque la interaccion entre el genotipo y el conjunto de umbrales fue significativa, la diferencia entre ambos genotipos en la varianza de la prolificidad sobre la escala observada a una prolificidad media dada es escasa y muy poco relevante EnglishThe effects of the BMP15 gene, located on the X chromosome, on mean prolificacy and its variability, were estimated in the Rasa Aragonesa sheep population through the analysis of 918,956 lambing records from ewes of different genotypes (FecXR or ROA® heterozygous ewes; and non-carrier ewes). Threshold models including or not the gene effect were first run to determine the effect of the BMP15 genotype and its importance in the total genetic variability of prolificacy. Two other models were also run to estimate the interaction between the BMP15 genotype and the polygenic background, as well as the effect of the genotype on the variability of prolificacy. All the models were run using the ASReml software. The effect of the presence of the ROA® allele of the BMP15 gene on the mean prolificacy was 0.32 extra lambs per lambing. Due to the selection on prolificacy performed during many years in this population ignoring the presence of this major gene, animals carrying the mutation were found to have lower remaining polygenic estimated breeding values than non-carrier animals, and there was no interaction between the BMP15 genotype and the polygenic background. Although the interaction between the genotype and the set of thresholds was significant, the resulting between-genotypes difference of variance of prolificacy on the observed scale, at a similar mean litter size, was very low and not relevant

The aim of this study was to evaluate the effect of rosemary essential oils (REO) and the forage nature on ewes' performances, immune response and lambs' growth and mortality. Forty-eight dairy ewes (Sicilo-Sarde) were fed oat-hay or oat-silage supplemented with 400 g of concentrate during pregnancy and 600 g during postpartum. The experimental concentrate contained the same mixture as the control (barley, soybean meal and mineral vitamin supplement) more 0.6 g/kg of REO. Two groups were obtained with each forage (Hay groups: H-C and H-REO; Silage groups: S-C and S-REO). REO increased the dry matter (DM) intake, the nitrogen intake and retention being higher with the silage groups (P 0.05). REO increased solid non-fat (P = 0.004) and fat contents of colostrum which was higher with hay (P = 0.002). REO decreased lamb mortality (P 0.05) which averaged 21% for control groups and 6% for H-REO, while no mortality was recorded with S-REO. REO dietary supply improved forage intake and tended to ameliorate colostrum production; it could be a natural additive to improve ewes' performances.

The main bridge over the Danube River between Vidin (Bulgaria) and Calafat (Calafat) has a total length of 1391 m. It has three different decks depending on the span lengths. The road bridge has a 80 m deck for the non-navigable part of the river and a 180 m deck for the navigable one, thus allowing two navigable channels of 150 m. The railway has 40 m span lengths with intermediate supports at one fourth over the road bridge on the 80 m spans. The span distribution is: 52.0 + 7x80.0 + 124.0 + 3x180.0 + 115.0 m. Expansion joints are included only in the three abutments, thus configuring an integral bridge of 1791 m.

La presencia del alelo FecXR en heterocigosis produce un incremento de la tasa de ovulación y prolificidad, así como una mayor respuesta a la eCG. Sin embargo, todavía se desconocen sus posibles efectos sobre la descarga preovulatoria de LH, lo cual es esencial para realizar la inseminación artificial en el momento óptimo. Con este objetivo, se extrajeron muestras sanguíneas a intervalos de 4-6 horas durante las 72 horas siguientes a la retirada de una esponja (FGA, 30 mg), de 50 ovejas adultas agrupadas en 5 lotes en función de su genotipo (R+ y ++; portadoras y no portadoras) y tratamiento hormonal (sin eCG, 240 ó 480 UI). Las concentraciones de LH se analizaron mediante un kit comercial ELISA. No se observó ninguna diferencia significativa en el pico preovulatorio de LH entre ovejas R+ y ++. La eCG adelantó la descarga preovulatoria de LH en ambos genotipos, sin diferencias entre ovejas R+ tratadas con 240 ó 480 UI. Estos resultados demuestran que la presencia de FecXR no afecta al pico preovulatorio de LH, independientemente de la dosis utilizada. Por lo tanto, la dosis de eCG que se aplique a las ovejas R+ estará en función de las necesidades y posibilidades de la explotación para asumir una mayor prolificidad y multiplicidad de partos. En las ovejas ++ tratadas con eCG se recomienda seguir inseminando a las 54 ± 1 horas de retirar las esponjas, como se hace habitualmente, ya que se observó una buena sincronización del pico preovulatorio de LH a las 37 horas The presence of the FecXR allele in heterozygosity (R+) increases ovulation rate and prolificacy in Rasa Aragonesa ewes, and leads to a greater response to eCG. However, their potential effects on preovulatory LH surge are still unknown, which is essential to establish the optimum time for artificial insemination. With this aim, blood samples were taken at 4-6 hours intervals during 72 hours after the removal of a 30 mg FGA sponge, from 50 adult ewes divided in 5 groups depending on their genotype (R+ and ++; carriers and non-carriers) and hormonal treatment (without eCG, 240 or 480 IU). The LH concentrations were analyzed using a commercial ELISA kit. There was no significant difference on the time of the preovulatory LH surge between R+ and ++ ewes. Treatment with eCG significantly advanced the preovulatory LH discharge in both genotypes, with no difference between R+ ewes treated with 240 or 480 IU. These results demonstrate that the presence of the FecXR allele did not affect the preovulatory LH surge, regardless of eCG dose. Therefore, the dose of eCG that should be applied to R+ ewes could be a decision of the farmer depending on the needs and possibilities of the farm to manage greater prolificacy and multiple births. In ++ ewes treated with eCG it is recommended to continue with the established protocol and inseminate 54 ± 1 hours after sponge withdrawal, as it is usually done, since a good synchronization of the preovulatory LH peak was observed at 37 hours inseminación artificial prolificidad BMP15 eCG raza Rasa aragonesa ovulación PMSG Published Premio Prensa Agraria 2013 otorgado por A.I.D.A.

At Paranal Observatory in the YEPUN (UT4) telescope, two instruments are installed and equipped with adaptive optics systems: an infrared spectro imager (CONICA) below the adaptive optics module NAOS; and an integral field spectrograph (SINFONI). In the same telescope, the Laser Guide Star Facility (LGSF) is installed to provide a reference star to the adaptive optics systems. The LGSF is tuned to the sodium D2 line to use the resonance fluorescence of atomic sodium in the mesospheric layer at an altitude of 90 Km. The LGSF system has been fully operational for several years now. During this time, important modifications have been made to the system to increase its availability, simplify its remote operation and improve its performance. In this contribution, we report on the latest upgrades in hardware as well as the software of the system. Some upgrades like the exchange of the cooling system of the VERDI lasers, as well as the exchange of motors in the PARSEC laser system, have been critical to improve the performance of the system. We also describe the improvements in the maintenance and operation procedures and operational constraints we have faced so far. Finally, we present and analyze the latest technical performance achieved by the LGSF in operational conditions.

This presentation provides interesting miscellaneous information regarding the instrumentation activities at Paranal Observatory. It introduces the suite of 23 instruments and auxiliary systems that are under the responsibility of the Paranal Instrumentation group, information on the type of instruments, their usage and downtime statistics. The data is based on comprehensive data recorded in the Paranal Night Log System and the Paranal Problem Reporting System whose principles are explained as well. The work organization of the 15 team members around the high number of instruments is laid out, which includes: - Maintaining older instruments with obsolete components - Receiving new instruments and supporting their integration and commissioning - Contributing to future instruments in their developing phase. The assignments of the Instrumentation staff to the actual instruments as well as auxiliary equipment (Laser Guide Star Facility, Mask Manufacturing Unit, Cloud Observation Tool) are explained with respect to responsibility and scheduling issues. The essential activities regarding hardware & software are presented, as well as the technical and organizational developments within the group towards its present and future challenges.

The Laser Guide Star Facility (LGSF) is installed on the UT4 (Yepun) telescope at Paranal Observatory in Chile. On the same telescope, two instruments are equipped with adaptive optics: an infrared spectro imager (CONICA) below the adaptive optics module NAOS; and an integral field spectrograph (SINFONI). The LGSF is tuned to the sodium D2 line to generate an artificial reference star, for both CONICA and SINFONI. Although the LGSF is a complex laser system, rather different from the other instruments at Paranal, it has been designed to run remotely without any hand-on tuning for a period of one week. The LGSF system has now been in operation for several months, in conjunction with the Aircraft camera Avoidance System (AAS). In this article, we report on the technical performance achieved by the LGSF in operational conditions. We also provide a summary of the technical problems and operational constraints we have faced so far. We present the current operations and maintenance procedures implemented at Paranal. We also present the evolution of the human resources needed to operate and maintain the LGSF operational from commissioning to routine operations. Finally, we discuss possible improvements to reduce the workload to maintain and operate the LGSF.

The European Southern Observatory (ESO) operates its Very Large Telescope (VLT) on Cerro Paranal (Chile) with to date 11 scientific instruments including two interferometric instruments and their numerous auxiliary systems at 4 Unit Telescopes (UTs) and 3 Auxiliary Telescopes (ATs). The rigorous application of preventive and corrective maintenance procedures and a close monitoring of the instruments' engineering data streams are the key ingredient towards the minimization of the technical downtime of the instruments. The extensive use of standardized hardware and software components and their strict configuration control is considered crucial to efficiently manage the large number of systems with the limited human and technical resources available. A close collaboration between the instrument engineers, the instrument scientists in instrument operation teams (IOTs) turns out to be vital to maintain and to the performance of the instrumentation suite. In this paper, the necessary tools, workflows, and organizational structures to achieve these objectives are presented.

Two teams of scientists and engineers at Max Planck Institut fuer Extraterrestrische Physik and at the European Southern Observatory have joined forces to design, build and install the Laser Guide Star Facility for the VLT. The Laser Guide Star Facility has now been completed and installed on the VLT Yepun telescope at Cerro Paranal. In this paper we report on the first light and first results from the Commissioning of the LGSF.

The Simultaneous Multiple Surface (SMS) method in 3D geometry is presented. Giving two orthotomic input ray bundles and other two orthotomic output ray bundles, the method provides an optical system with two free-form surfaces that deflects the rays of the input bundles into the rays of the corresponding output bundles and vice versa. In nonimaging applications, the method allows controlling the light emitted by an extended light source much better than single free-form surfaces designs, and also enables the optics contour to be shaped without efficiency losses. The method is expected to find also applications in imaging optics

In this work it is presented a new design of a TIR lens-mushrooms lens device developed with the Simultaneous Multiple Surfaces (SMS) method. In SMS nomenclature, it is named TIR-R. In contrast to previous TIR-mushroom designs, application of the SMS method to this configuration consists in the simultaneous design of both TIR (total internal reflection) and R (refraction) optical surfaces using extended ray-bundles and the edge-ray theorem. In this paper is presented a basic approach to do the design. In this basic approach, first it is considered the TIR lens as a microstructured surface with infinitesimal flat facets. Afterwards, it is generated a TIR lens with finite size facets from the already designed one. In an advanced approach could be considered the TIR lens with finite facet size and designed simultaneously each facet with a portion of the outer surface of the mushroom lens. With respect to others SMS high-gain devices (as the RXI), the TIR-R concentrator has the following advantages: is a mirror-less device, there is not shadowing elements, and the receiver/emitter element's placement is more favorable for encapsulation and electrical connection. As it is common in the SMS devices, the TIR-R concentrator achieves wide acceptance angle and high efficiency with a low aspect ratio (thickness to entry aperture diameter ratio). For example, a 1256X concentration device has a theoretical efficiency of 100 percent (without optical losses) with an acceptance angle of +/- 1.7 decgrees, and an aspect ratio of 0.34.

Advanced optical design methods using the keys of nonimaging optics lead to some ultra compact designs which combine the concentrating (or collimating) capabilities of conventional long focal length systems with a high collection efficiency. One of those designs is the so-called RXI. Its aspect ratio (thickness/aperture diameter) is less than 1/3. Used as a receiver, i.e. placing a photodiode at the proper position, it gets an irradiance concentration of the 95% of the theoretical thermodynamic limit (this means for example, a concentration of 1600 times with an acceptance angle of +/- 2.14 degrees). When used as an emitter (replacing the aforementioned photodiode by an LED, for instance), similar intensity gains may be obtained within an angle cone almost as wide as the 95% of the thermodynamic limit. In a real device these irradiance(and intensity)gains are reduced by the optical efficiency. This combination of high concentration factors, relatively wide angles, simplicity and compactness make the optical device almost unique. This work will show the results of the measurements done with several RXI prototypes of 40-mm aperture diameter, all of them made of PMMA (by injection process).

The purpose of this work is to present the measurements of the main characteristics of a series of RXI concentrators developed: angular transmission, acceptable angle, optical efficiency, and optical concentration. The RXI concentrator has been designed with the Simultaneous Multiple Surfaces method developed by Minano et al. at the Instituto de Energia Solar--Universidad Politecnica de Madrid. The design characteristics are: geometric concentration 1256X, acceptance angle 1.8 degree(s).© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Four slime-producing isolates of Staphylococcus aureus were used in an antibiotic susceptibility assay for biofilms developed on 96-well polystyrene tissue culture plates. The study involved 11 antibiotics, two biofilm ages (6 and 48 h), two biofilm growth media (tryptone soy broth (TSB) and delipidated milk) and three antibiotic concentrations (4 x MBC, 100 mg/L and 500 mg/L). ATP-bioluminescence was used for automated bacterial viability determination after a 24 h exposure to antibiotics, to avoid biofilm handling. Under the conditions applied, viability in untreated biofilms (controls) was lower when biofilm growth was attempted in milk rather than in TSB. Various antibiotics had a greater effect on viability when used at higher (> or =100 mg/L) antibiotic concentrations and on younger (6 h) biofilms. Increased antibiotic effect was observed in milk-grown rather than TSB-grown biofilms. Phosphomycin and cefuroxime, followed by rifampicin, cefazolin, novobiocin, vancomycin, penicillin, ciprofloxacin and tobramycin significantly affected biofilm cell viability at least under some of the conditions tested. Gentamicin and erythromycin had a non-significant effect on cell viability. Transmission electron microscopy revealed that cells at the inner biofilm layers tend to remain intact after antibiotic treatment and that TSB-grown biofilms favoured a uniformity of cell distribution and increased cell density in comparison with milk-grown biofilms. A reduced matrix distribution and enhanced cell density were observed as the biofilm aged. The S. aureus biofilm test discriminated antibiotics requiring shorter (3 h or 6 h) from those requiring longer (24 h) exposure and yielded results which may be complementary to those obtained by conventional tests.

A small series of nonimaging RXI concentrators designed for concentrating radiation on a 1 mm2 photodiode have been manufactured by injection molding of PMMA (polymethyl methacrylate). Their entry aperture diameter is 40 mm and the design acceptance angle is +/- 2.24 degrees. Measurements done at (lambda) equals 890 nm show an optical efficiency of 33.8% and the relative transmission drops from 90% to 10% when the incidence angle varies from 1.2 to 3.4 degrees. A computer model of the concentrator which takes into account the different optical losses shows that optical efficiency is increased up to 57.1 % using silver metallization and (lambda) equals 800 nm. Moreover if photodiode position error is corrected, then the efficiency grows up to 76.2%, and if profile errors are also corrected, then the efficiency reach 88.2%. A more stepped angular transmission requires a most accurate manufacture process.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Advanced optical design methods using the tools of nonimaging optics (instead of conventional imaging tools) produce ultracompact devices that combine high collection efficiency with a concentration (or collimating) capability close to the thermodynamic limit. After a general overview covering the most important design methods and devices in nonimaging optics, two of these designs, the so-called RX and RXI, are presented. Even though it is designed within the nonimaging framework, the RX device nevertheless has imaging properties that complement its valuable performance as a nonimaging device. The RXI is extremely compact: its aspect ratio (thickness/aperture diameter) is less than 1/3. When working as a receiver, that is, by placing a photodiode in the correct position, it attains an increase in irradiance that takes it beyond 95% of the theoretical thermodynamic limit (i.e., a concentration of 1600 times with an acceptance angle of ±2.14 deg). As an emitter, similar intensity gains can be obtained within an angle almost as large as 95% of the thermodynamic limit. The combination of high concentration factors, relatively wide acceptance angles, simplicity, and compactness makes these devices almost unique. The measurements carried out with several RXI prototypes, all of them made by PMMA injection, are also presented. Sin financiación 0.942 JCR (2000) Q2, 22/57 Optics UEM