Space Evaluation of Optical Modulators for Microwave Photonic On-Board Applications

Since several years, perspectives and assets offered by photonic technologies compared with their traditional RF counterparts (mass and volume reduction, transparency to RF frequency, RF isolation), make them particularly attractive for space applications [1] and, in particular, telecommunication satellites [2]. However, the development of photonic payload concepts have concurrently risen and made the problem of the ability of optoelectronic components to withstand space environment more and more pressing. Indeed, photonic components used in such photonic payloads architectures come from terrestrial networks applications in order to benefit from research and development in this field. This paper presents some results obtained in the frame of an ESA-funded project, carried out by Thales Alenia Space France, as prime contractor, and Alter Technology Group Spain (ATG) and Universidad Politecnica de Madrid (UPM), as subcontractors, one objective of which was to assess commercial high frequency optical intensity modulators for space use through a functional and environmental test campaign. Their potential applications in microwave photonic sub-systems of telecom satellite payloads are identified and related requirements are presented. Optical modulator technologies are reviewed and compared through, but not limited to, a specific figure of merit, taking into account two key features of these components : optical insertion loss and RF half-wave voltage. Some conclusions on these different technologies are given, on the basis of the test results, and their suitability for the targeted applications and environment is highlighted

On-Offer and Residual Forage in a Massai-\u3cem\u3eLeucaena\u3c/em\u3e Pasture at Different Leucaena Density

Mexican livestock producers in tropical areas are increasingly interested on the establishment of silvopastoral systems based on Leucaena (Leucaena leucocephala (Lam.) de Wit) and different tropical grasses as the Massai grass (Panicum maximum cv Massai); among questions raised on this is the importance of Leucaena density in relation to forage available. Then the objective of the study was to determine total and by species on-offer and residual forage in a grazed MassaiLeucaena pasture with different Leucaena density

Comparación de estructuras oceanográficas observadas a través del SAR, AVHRR y Seawifs en las Islas Canarias

Ponencia presentada en: 1er Encuentro sobre Meteorología y Atmósfera de Canarias, celebrado en el Puerto de la Cruz, los días 12,13 y 14 de noviembre de 2003. El encuentro estuvo organizado por el Centro Meteorológico Territorial en Canarias Occidental, con la colaboración del Observatorio Atmosférico de Izaña y del Grupo de Física de la Atmósfera de la Facultad de Física (Universidad de La Laguna)El archipiélago canario se encuentra dinámicamente dentro de régimen de recirculación de la corriente del Golfo, en el seno de la corriente de Canarias y se caracteriza a su vez por su proximidad con el área de afloramiento del banco canario-sahariano. Las diferencias zonales de temperatura del agua superficial del mar se establecen entre aguas costeras y oceánicas en la zona que evidencia la presencia de dicho afloramiento costero debido principalmente a las variaciones estacionales del alisio a lo largo de la costa del noroeste africano. Las imágenes de satélite son utilizadas como herramienta importante en el estudio de fenómenos de afloramiento , mediante las cuales podemos cubrir un mayor área de trabajo, localizar estructuras e identificar las condiciones anteriores y posteriores al evento típicas del parámetro de estudio

Quantum Zeno and anti-Zeno effects in surface diffusion of interacting adsorbates

Surface diffusion of interacting adsorbates is here analyzed within the context of two fundamental phenomena of quantum dynamics, namely the quantum Zeno effect and the anti-Zeno effect. The physical implications of these effects are introduced here in a rather simple and general manner within the framework of non-selective measurements and for two (surface) temperature regimes: high and very low (including zero temperature). The quantum intermediate scattering function describing the adsorbate diffusion process is then evaluated for flat surfaces, since it is fully analytical in this case. Finally, a generalization to corrugated surfaces is also discussed. In this regard, it is found that, considering a Markovian framework and high surface temperatures, the anti-Zeno effect has already been observed, though not recognized as such.Comment: 17 pages, 1 figur

Reporte del ácaro parásito Varroa destructor (Anderson & Trueman) en colmenas (Apis mellifera L.) de una zona de la provincia de La Habana

It  is a well-known fact that varroasis is the most significant worldwide disease suffered by Apis mellifera L. bees; however, in Cuba it has been a biological disaster taking into account the great number of dead hive bees and the severe conditions of survivor bees. As Varroa destructor  is a macroscopic akaryon and due to the above mentioned situation, it seems that  all attention was placed upon the epizooty control, leaving the parasite study aside with only  a preliminary finding report from Matanzas province. A later attempt regarding this study was almost reduced to nothingness. Information from analytical keys revealed that the studied akaryon specimen characteristics corresponded to the species. Varroa jacobsoni Oudemans;  however, the need of a deeper study was evident as indicated by the reports on the virulence range attributed to the Russian (J), Japanese (J), and Papua New Guinea (PNG) genotypes and the possible existence of some others. Latter researches and a generalized judgment, together with the mor- phological evidences gathered, made possible to affirm that the akaryon specimens studied in the area belonged to the new species Varroa destructor Anderson & Trueman, although it has been impossible to determine the existing holotype(s) unless a DNA test can be performed.Es indudable que en el mundo, la varroasis constituye la más importante enfermedad de la abeja (Apis mellifera L.) y particu- larmente en Cuba ha ocasionado un efecto que alcanzó categoría de desastre biológico, por la gran cantidad de colmenas muertas y el considerable deterioro de las supervivientes. Tratándose de un ácaro macroscópico y bajo la presión de la grave situación, ocurrió que, al parecer, toda la atención se dirigió al control de la epizootia y el estudio del parásito quedó en el reporte preliminar de su hallazgo en la provincia de Matanzas. Apenas se había realizado un intento posterior de avance en este sentido. Para el nivel del conocimientos que expresaban las claves hasta hace poco, las características de los especímenes del ácaro estudiados corres- pondían a la especie Varroa jacobsoni Oudemans, aunque evidentemente se hacía necesario profundizar mucho más, partiendo de los reportes existentes acerca del diverso grado de virulencia que se le atribuía a los genotipos Ruso (R), Japonés (J) y Papúa Nueva Guinea (PNG) y la posibilidad de que existieran otros. Las últimas investigaciones y el criterio generalizado, unido a las evidencias morfológicas, permiten enunciar que los especímenes del ácaro estudiados en esta área pertenecen a la nueva especie Varroa destructor Anderson & Trueman, aunque por supuesto, resulta imposible determinar el o los halotipos presentes si no se realiza el estudio del ADN

Evaluación del efecto de tres condiciones de cultivo in vitro en la calidad de plántulas de caña de azúcar propagadas en Biorreactores de Inmersión Temporal

Structural and functional deficiencies that affect survival during acclimatization are present in micropropagated plants. The current study was carried out to determine the effect of three in vitro culture conditions (autotrophic, mixotrophic and moderate mixotrophic) on the morph-physiological and biochemical behavior of plantlets of sugar cane propagated in Temporary Immersion Bioreactors (BIT). Morphological and physiological indicators and key enzymes of carbon metabolism were evaluated. Plantlets that were subjected to autotrophic conditions did not survive due to the stress caused by the absence of sucrose in the culture medium. For this reason it could not be evaluated. The best results were obtained for the condition of moderate mixotrofical. In this case, the morphological variables, height of the plants, fresh weight and dry weight, responded positively. It was minimum the answer of the net photosynthesis in vitro and increased it notably from the second week of acclimatization. Plants with a mixotrophic growth showed very high values of transpiration and estomatic conductance at the beginning of the elongation and during the first week of acclimatization. This group of plants took a longer time than the rest in achieving the control of the loss of water and in reaching a functional stability. Plants that showed a bigger activity of pyruvate kinase were those coming from mixotrophic conditions. An inverse behavior was observed in the phosphoenolpyruvate carboxylase. The activities of syntase sucruse and the neutral invertase were superior for the mixotrofic conditions.Key words: autotrofic, enzymes, mixotrofic, photosynthesisLas plantas micropropagadas poseen deficiencias estructurales y funcionales que comprometen su supervivencia durante la aclimatización. El objetivo de este trabajo fue determinar el efecto de tres condiciones de cultivo in vitro (autotrófica, mixotrófica y de mixotrofismo moderado) en el comportamiento morfo-fisiológico y bioquímico de plántulas de caña de azúcar propagadas en Biorreactores de Inmersión Temporal (BIT). Se evaluaron indicadores morfológicos, fisiológicos y enzimas clave del metabolismo del carbono. Las plántulas que se sometieron a condiciones autotróficas no lograron sobrevivir debido al estrés propiciado por la ausencia de sacarosa en el medio de cultivo. Por esta razón no pudieron ser evaluadas. Los mejores resultados se obtuvieron para la condición de mixotrofismo moderado. En este caso, las variables morfológicas altura de las plantas, masas fresca y seca respondieron positivamente. La respuesta de la fotosíntesis neta fue muy baja in vitro y aumentó notablemente a partir de la segunda semana de aclimatización. Para las plántulas con un desarrollo mixotrófico se observaron valores de transpiración y conductancia estomática muy elevados al inicio de la elongación y durante la primera semana de aclimatización. Este grupo de plántulas se tardó más que el resto en lograr el control de la pérdida de agua y en alcanzar una estabilidad funcional. Las plantas que mostraron una mayor actividad de la Piruvato Quinasa fueron provenientes de condiciones mixotróficas. La Fosfoenol Piruvato Carboxilasa tuvo un comportamiento totalmente inverso. Las actividades de la Sacarosa Sintasa y la Invertasa Neutra, al igual que la Piruvato Quinasa, fueron superiores para las condiciones mixotróficas.Palabras clave: autotrofismo, enzimas, fotosíntesis, mixotrofism

Association of APOA5 and APOC3 genetic polymorphisms with severity of hypertriglyceridemia in patients with cutaneous T-Cell lymphoma treated with bexarotene

Importance: hypertriglyceridemia is the most frequent and limiting adverse effect of bexarotene therapy in cutaneous T-cell lymphoma (CTCL). Despite standard prophylactic measures, there is a wide variability in the severity of this complication, which could be associated with both genetic and environmental factors. Objectives: to analyze the association between genetic polymorphisms of apolipoprotein genes APOA5, APOC3, and APOE and the severity of hypertriglyceridemia during bexarotene therapy and to optimize patient selection for bexarotene therapy based on adverse effect profile. Design, Setting, and Participants: this case series study was conducted in 12 university referral hospitals in Spain from September 17, 2014, to February 6, 2015. One hundred twenty-five patients with a confirmed diagnosis of CTCL who had received bexarotene therapy for at least 3 months were enrolled. Nine patients were excluded owing to missing analytic triglyceride level data, leaving a study group of 116 patients. Data on demographic and cardiovascular risk factor were collected, and a complete blood analysis, including lipid profile and genetic analysis from a saliva sample, was performed. Main Outcomes and Measures: primary outcomes were the maximal triglyceride levels reported in association with the minor alleles of the polymorphisms studied. Results: among 116 patients, the mean (SD) age was 61.2 (14.7) years, 69 (59.5%) were men, and 85 (73.2%) had mycosis fungoides, the most prevalent form of CTCL. During bexarotene therapy, 96 patients (82.7%) experienced hypertriglyceridemia, which was severe or extreme in 8 of these patients (8.3%). Patients who carried minor alleles of the polymorphisms did not show significant differences in baseline triglyceride concentrations. After bexarotene treatment, carriers of at least 1 of the 2 minor alleles of APOA5 c.-1131T>C and APOC3 c.*40C>G showed lower levels of triglycerides than noncarriers (mean [SD], 241.59 [169.91] vs 330.97 [169.03] mg/dL, respectively; P = .02). Conclusions and Relevance: these results indicate that the screening of APOA5 and APOC3 genotypes may be useful to estimate changes in triglyceride concentrations during bexarotene treatment in patients with CTCL and also to identify the best candidates for bexarotene therapy based on the expected adverse effect profile

First-line treatment in lymphomatoid papulosis: a retrospective multicentre study

Background: Data regarding response to treatment in lymphomatoid papulosis (LyP) are scarce. Aim: To assess the daily clinical practice approach to LyP and the response to first-line treatments. Methods: This was a retrospective study enrolling 252 patients with LyP. Results: Topical steroids, methotrexate and phototherapy were the most common first-line treatments, prescribed for 35%, 20% and 14% of the patients, respectively. Complete response (CR) was achieved in 48% of treated patients. Eczematous lesions significantly increased relative risk (RR) of not achieving CR (RR = 1.76; 95% CI 1.16-2.11). Overall median time to CR was 10 months (95% CI 6-13 months), and 78% of complete responders showed cutaneous relapse; both results were similar for all treatment groups (P > 0.05). Overall estimated median disease-free survival (DFS) was 11 months (95% CI 9-13 months) but DFS for patients treated with phototherapy was 23 months (95% CI 10-36 months; P < 0.03). Having the Type A LyP variant (RR = 2.04; 95% CI 0.96-4.30) and receiving a first-line treatment other than phototherapy (RR = 5.33; 95% CI 0.84-33.89) were significantly associated with cutaneous early relapse. Of the 252 patients, 31 (13%) had associated mycosis fungoides unrelated to therapeutic approach, type of LyP or T-cell receptor clonality. Conclusions: Current epidemiological, clinical and pathological data support previous results. Topical steroids, phototherapy and methotrexate are the most frequently prescribed first-line treatments. Although CR and cutaneous relapse rates do not differ between them, phototherapy achieves a longer DFS. Presence of Type A LyP and use of topical steroid or methotrexate were associated with an increased risk of early relapse