Fabrication of an efficient metal grating coupler for membrane-based integrated photonics

This paper reports the progress on the fabrication process of highly efficient metal grating couplers for membrane-based integrated circuits, using double side processing technology on bonded samples. This type of gratings comprises a buried SiO2/Ag grating of 125nm thickness with a silver layer as metal mirror, and has several advantages over dielectric gratings as metallic gratings are independent from the buffer thickness. We predict a theoretical chip-to-fiber coupling efficiency of 74% and 89% for uniform and apodized gratings respectively, at a wavelength of 1550 nm. Furthermore, the fabrication process can be used for both, SOI and III-V based platforms

Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works

The detection of exolife is one of the goals of very ambitious future space missions that aim to take direct images of Earth-like planets. While associations of simple molecules present in the planet's atmosphere ($O_2$, $O_3$, $CO_2$ etc.) have been identified as possible global biomarkers, we review here the detectability of a signature of life from the planet's surface, i.e. the green vegetation. The vegetation reflectance has indeed a specific spectrum, with a sharp edge around 700 nm, known as the "Vegetation Red Edge" (VRE). Moreover vegetation covers a large surface of emerged lands, from tropical evergreen forest to shrub tundra. Thus considering it as a potential global biomarker is relevant. Earthshine allows to observe the Earth as a distant planet, i.e. without spatial resolution. Since 2001, Earthshine observations have been used by several authors to test and quantify the detectability of the VRE in the Earth spectrum. The egetation spectral signature is detected as a small 'positive shift' of a few percents above the continuum, starting at 700 nm. This signature appears in most spectra, and its strength is correlated with the Earth's phase (visible land versus visible ocean). The observations show that detecting the VRE on Earth requires a photometric relative accuracy of 1% or better. Detecting something equivalent on an Earth-like planet will therefore remain challenging, moreover considering the possibility of mineral artifacts and the question of 'red edge' universality in the Universe.Comment: Invited talk in "Strategies for Life Detection" (ISSI Bern, 24-28 April 2006) to appear in a hardcopy volume of the ISSI Space Science Series, Eds, J. Bada et al., and also in an issue of Space Science Reviews. 13 pages, 8 figures, 1 tabl

Effect of B-site Dopants on Magnetic and Transport Properties of LaSrCoRuO6_6

Effect of Co, Ru and Cu substitution at B and B' sites on the magnetic and transport properties of LaSrCoRuO$_6$ have been investigated. All the doped compositions crystallize in the monoclinic structure in the space group $P2_1/n$ indicating a double perovskite structure. While the magnetization and conductivity increase in Co and Ru doped compounds, antiferromagnetism is seen to strengthen in the Cu doped samples. These results are explained on the basis of a competition between linear Co-O-Ru-O-Co and perpendicular Co-O-O-Co antiferromagnetic interactions and due to formation of Ru-O-Ru ferromagnetic networks

Garvey-Kelson Relations for Nuclear Charge Radii

The Garvey-Kelson relations (GKRs) are algebraic expressions originally developed to predict nuclear masses. In this letter we show that the GKRs provide a fruitful framework for the prediction of other physical observables that also display a slowly-varying dynamics. Based on this concept, we extend the GKRs to the study of nuclear charge radii. The GKRs are tested on 455 out of the approximately 800 nuclei whose charge radius is experimentally known. We find a rms deviation between the GK predictions and the experimental values of only 0.01 fm. This should be contrasted against some of the most successful microscopic models that yield rms deviations almost three times as large. Predictions - with reliable uncertainties - are provided for 116 nuclei whose charge radius is presently unknown.Comment: 4 pages and 3 figure

Impacto psicosocial en adultos con dermatitis atópica: estudio cualitativo

Antecedentes y objetivo La dermatitis atópica afecta a la calidad de vida del paciente de muchas maneras. Por tanto, es importante analizar los efectos que la enfermedad produce en la vida del paciente al objeto de definir mejor las necesidades de atención de los pacientes adultos con dermatitis atópica. Pacientes y métodos Se realizaron entrevistas a 14 pacientes adultos con dermatitis atópica. Las entrevistas cualitativas fueron semiestructuradas apoyadas en un guion simple, lo que permitió una entrevista completa y flexible para un mayor nivel de profundidad y riqueza de datos. Resultados Se identificaron 6 esferas afectadas de la vida del paciente con dermatitis atópica: económica, laboral, personal, psicosocial, clínica y relacional. Se destaca que la dermatitis atópica tiene un gran impacto psicosocial en el paciente adulto, ya que altera las relaciones interpersonales, genera rechazo, estigmatización y aislamiento social, limita al paciente en diversas áreas y actividades de su vida cotidiana o altera el sueño, entre otros. Preocupan mucho el aspecto visible, el ciclo picor-rascamiento, la falta de concienciación y desconocimiento de la enfermedad, la ausencia de una solución definitiva entre los tratamientos y los efectos secundarios de algunos de ellos. Conclusiones La calidad de vida de los pacientes con dermatitis atópica se ve afectada negativamente y se hace necesaria una intervención profesional desde un abordaje multidisciplinar holístico que intente mitigar el impacto negativo de la enfermedad. Background and objective: Atopic dermatitis affects a patient''s quality of life in many ways. Analysis of the effects of this disease on the lives of adult patients is therefore important for the purpose of better defining their care needs. Patients and methods: We interviewed 14 adult patients with atopic dermatitis in this qualitative study. The interviews were semistructured according to a simple outline to allow for completeness and flexibility and afford greater depth and richness of information. Results: Atopic dermatitis affected the patients’ lives in 6 spheres of activity: economic, occupational, personal, psychosocial, clinical, and relational. A clear finding was that the disease has a considerable psychosocial effect on adult patients, altering their interpersonal relationships and leading to rejection, stigmatization, and social isolation. It limits the patient in various spheres of life and in activities of daily living, causing sleep alterations among other effects. The patients were very concerned about appearance, the itch–scratch cycle, poor understanding and lack of awareness of their disease, the absence of a definitive treatment, and the adverse effects of some treatments. Conclusions: The quality of life of adults with atopic dermatitis is negatively affected. This disease requires a professional, holistic, multidisciplinary management approach that attempts to mitigate the adverse effects

A comparison of clinical pharmacodynamics of different administration schedules of oral topotecan (Hycamtin)

Prolonged exposure to topotecan in in vitro and in vivo experiments has yielded the highest antitumor efficacy. An oral formulation of topotecan with a bioavailability of 32-44% in humans enables convenient prolonged administration. Pharmacokinetic/pharmacodynamic relationships from four Phase I studies with different schedules of administration of oral topotecan in 99 adult patients with malignant solid tumors refractory to standard forms of chemotherapy were compared. Topotecan was administered as follows: (a) once daily (o.d.) for 5 days every 21 days (29 patients); (b) o.d. for 10 days every 21 days (19 patients); (c) twice daily (b.i.d.) for 10 days every 21 days (20 patients); and (d) b.i.d. for 21 days every 28 days (31 patients). Pharmacokinetic analysis was performed in 55 patients using a validated high-performance liquid chromatographic assay and noncompartmental pharmacokinetic me

A Performance Analysis Framework for WiFi/WiMAX Heterogeneous Metropolitan Networks Based on Cross-Layer Design

The communication between network nodes within different protocol domains is often regarded simply as a black box with unknown configuration conditions in the path. We address network heterogeneity using a white box approach and focus on its interconnection processes. To achieve this purpose, a Performance Analysis Framework (PAF) is proposed which is composed of the formalization of the latter using process algebra (PA) and the corresponding teletraffic performance models. In this contribution, we target the IEEE 802.16 and IEEE 802.11 protocols. For the teletraffic models, we extend previous models for such scenario with the inclusion of the following protocol operational parameters (metrics): bit error rate (BER), packet error ratio (PER), and packet length (pl). From the framework teletraffic models, the optimal packet length (OPL), end to end throughput, delay, and packet loss are obtained. The PAF outperforms previous modeling solutions in terms of delay and throughput relative to NS3 simulation results. </jats:p

Neutrinoless double-beta decay and seesaw mechanism

From the standard seesaw mechanism of neutrino mass generation, which is based on the assumption that the lepton number is violated at a large (~10exp(+15) GeV) scale, follows that the neutrinoless double-beta decay is ruled by the Majorana neutrino mass mechanism. Within this notion, for the inverted neutrino-mass hierarchy we derive allowed ranges of half-lives of the neutrinoless double-beta decay for nuclei of experimental interest with different sets of nuclear matrix elements. The present-day results of the calculation of the neutrinoless double-beta decay nuclear matrix elements are briefly discussed. We argue that if neutrinoless double-beta decay will be observed in future experiments sensitive to the effective Majorana mass in the inverted mass hierarchy region, a comparison of the derived ranges with measured half-lives will allow us to probe the standard seesaw mechanism assuming that future cosmological data will establish the sum of neutrino masses to be about 0.2 eV.Comment: Some changes in sections I, II, IV, and V; two new figures; additional reference

Determination of ππ\pi\pi scattering lengths from measurement of π+π−\pi^+\pi^- atom lifetime

The DIRAC experiment at CERN has achieved a sizeable production of $\pi^+\pi^-$ atoms and has significantly improved the precision on its lifetime determination. From a sample of 21227 atomic pairs, a 4% measurement of the S-wave $\pi\pi$ scattering length difference $|a_0-a_2| = (.0.2533^{+0.0080}_{-0.0078}|_\mathrm{stat}.{}^{+0.0078}_{-0.0073}|_\mathrm{syst})M_{\pi^+}^{-1}$ has been attained, providing an important test of Chiral Perturbation Theory.Comment: 6 pages, 6 figure

Effects of thermoregulation on human sleep patterns: A mathematical model of sleep-wake cycles with REM-NREM subcircuit

In this paper we construct a mathematical model of human sleep/wake regulation with thermoregulation and temperature e ects. Simulations of this model show features previously presented in experimental data such as elongation of duration and number of REM bouts across the night as well as the appearance of awakenings due to deviations in body temperature from thermoneutrality. This model helps to demonstrate the importance of temperature in the sleep cycle. Further modi cations of the model to include more temperature e ects on other aspects of sleep regulation such as sleep and REM latency are discussedPostprint (author's final draft