Analytical study of the proximity of exoplanetary systems to mean-motion resonances

Aims.In a previous paper (Libert & Henrard 2005, Celest. Mech. & Dyn. Astron., 93, 187) we used a twelfth-order expansion of the perturbative potential in powers of eccentricities to represent the secular effects of two coplanar planets. This expansion was applied successfully to non resonant exoplanetary systems. This study was based on a first order (in the masses of the planets) model and will fail for systems too close to a resonance. In this paper we test the effects of the proximity of a mean-motion resonance on the secular motion of the planets. Methods.We analyse the proximity of several exoplanetary systems to a mean-motion resonance zone by using a first-order (in the mass ratios) Lie algorithm on the perturbative potential expanded to the twelfth order in the eccentricities. This perturbation method evaluates the difference between osculating elements and averaged ones. It permits us to decide whether resonant contributions dominate the terms of this difference or not. Results.This study is applied to several exosystems. We find that HD 168443, HD 38529, HD 74156, HD 217107, and HD 190360 are far away from a mean-motion resonance zone. υ Andromedae and HD 12661 are rather close to the 5/1 resonance, HD 169830 to the 9/1 one. Hence, a secular theory is enough to depict correctly the behaviour of all these systems. On the other hand, HD 108874 and HD 202206 suffer from large perturbations in their motion due to the closeness of the 4/1 and 5/1 resonances, respectively. We also perform a complete investigation of the proximity of the υ Andromedae system to mean-motion resonances, by studying the changes in behaviour due to different values of the outer semi-major axis. The υ Andromedae system begins to be really influenced by the 5/1 resonant terms when the value of the outer semi-major axis decreases from 2.53 to 2.445

Transcriptomic Signature of Human Embryonic Thyroid Reveals Transition From Differentiation to Functional Maturation

The human thyroid gland acquires a differentiation program as early as weeks 3–4 of embryonic development. The onset of functional differentiation, which manifests by the appearance of colloid in thyroid follicles, takes place during gestation weeks 10–11. By 12–13 weeks functional differentiation is accomplished and the thyroid is capable of producing thyroid hormones although at a low level. During maturation, thyroid hormones yield increases and physiological mechanisms of thyroid hormone synthesis regulation are established. In the present work we traced the process of thyroid functional differentiation and maturation in the course of human development by performing transcriptomic analysis of human thyroids covering the period of gestation weeks 7–11 and comparing it to adult human thyroid. We obtained specific transcriptomic signatures of embryonic and adult human thyroids by comparing them to non-thyroid tissues from human embryos and adults. We defined a non-TSH (thyroid stimulating hormone) dependent transition from differentiation to maturation of thyroid. The study also sought to shed light on possible factors that could replace TSH, which is absent in this window of gestational age, to trigger transition to the emergence of thyroid function. We propose a list of possible genes that may also be involved in abnormalities in thyroid differentiation and/or maturation, hence leading to congenital hypothyroidism. To our knowledge, this study represent the first transcriptomic analysis of human embryonic thyroid and its comparison to adult thyroid

COMPLIS experiments : COllaboration for spectroscopy Measurements using a Pulsed Laser Ion Source

Laser spectroscopy measurements have been carried out on very neutron-deficient isotopes of Au, Pt and Ir, produced as daughter elements from a Hg ISOLDE beam. For these transitional region nuclides, the hyperfine structure (HFS) and isotope shift (IS) were measured by Resonance Ionization Spectroscopy (RIS). Magnetic moments μ, spectroscopic quadrupole moments Qs and changes of the nuclear mean square charge radius δ〈rc 2〉along isotopic series have been extracted. For some results, a detailed comparison with theoretical predictions is presented. (Springer

Controlling complexity: the clinical relevance of mouse complex genetics.

Experimental animal models are essential to obtain basic knowledge of the underlying biological mechanisms in human diseases. Here, we review major contributions to biomedical research and discoveries that were obtained in the mouse model by using forward genetics approaches and that provided key insights into the biology of human diseases and paved the way for the development of novel therapeutic approaches

Secure Blind Decryption

Abstract. In this work we construct public key encryption schemes that admit a protocol for blindly decrypting ciphertexts. In a blind decryp-tion protocol, a user with a ciphertext interacts with a secret keyholder such that the user obtains the decryption of the ciphertext and the key-holder learns nothing about what it decrypted. While we are not the first to consider this problem, previous works provided only weak secu-rity guarantees against malicious users. We provide, to our knowledge, the first practical blind decryption schemes that are secure under a strong CCA security definition. We prove our construction secure in the stan-dard model under simple, well-studied assumptions in bilinear groups. To motivate the usefulness of this primitive we discuss several applica-tions including privacy-preserving distributed file systems and Oblivious Transfer schemes that admit public contribution.

LA FUCOSIDOSE. ULTRASTRUCTURE OCULAIRE

An ultrastructural study of the eyes of a six year old girl affected with fucosidosis demonstrated widespread overloading of lysosomes with a fibrillo-granular material of variable density. Conjunctival and corneal epithelial cells, keratocytes, sclerocytes, fibroblasts, corneal endothelial cells, retinal ganglion cells, inner segments of photoreceptors as well as glial cells of the optic nerve were markedly involved by the storage process. On the contrary, the pigment epithelium of the retina, the ciliary body and the iris were unaffected. Membranous cytoplasmic bodies were only disclosed within Schwann cells of conjuctival and ciliary nerves. Particularly striking lesions were observed within the endothelial cells of capillaries and veins of the eyes, as well as in all tissues examined, like the liver, spleen, kidney, lung, brain and skin. On the contrary, artery walls remained intact. These lesions explain the development of retinal vascular tortuosities, conjunctival aneurysms and cutaneous angiomas that characterize the clinical picture of our patient and that are often discribed in fucosidosis. The massive overloading of retinal ganglion cells contrasts with the absence of a macular cherry-red spot in fucosidosis. The nature of the stored material is probably responsible for this apparent discrepancy. Indeed, ganglion cells contain membranous cytoplasmic bodies in all diseases with cherry-red spots, whereas only a fibrillo-granular material was disclosed in the present case.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

La toxicité des injections intravitréennes d'antibiotiques et antiviraux.

Intravitreal injections of antivirals, antifungals and antibiotics are very efficacious in the management of intraocular infections, which is not the case with per os, intravenous or peribulbar administration. However, these drugs have some toxic potential, more pronounced if used in intraocular condition. Being too toxic, aminoglycosides have been replaced by Ceftazidime and Vancomycine in the management of bacterial endophthalmitis. Efficacy of these drugs for prophylactic use is not demonstrated and their toxic potential remains to be kept in mind.SCOPUS: re.jinfo:eu-repo/semantics/publishe

LES MALADIES LYSOSOMIALES DE STOCKAGE ET LA RETINE

Metabolic storage diseases involving lysosomes can be divided into two groups, those which are hereditary, and those which are acquired, accidental or iatrogenic. About 30 hereditary lysosomal storage diseases have been recognised, and these are caused by genetically determined absence or insufficiency of certain enzymes. Ophthalmologists have an important role to play in diagnosis of these diseases, since the symptoms of the eye are often those which first draw attention to the disease. According to the disease, the clinical signs found in the eye may include corneal clouding, retinal pigment degeneration, optic atrophy, presence of a cherry-red spot, vascular tortuosities, and choroidal white dots. At our present state of knowledge the only effective method of treatment of these serious metabolic disorders is preventive medicine. Study of amniotic cells allows determination of whether the foetus is affected or not, and enables a decision as to whether the pregnancy should be terminated. Diagnosis of the disease depends on a combination of biochemical and histopathological methods and the combination of analysis of tears and of corneal biopsy is the easiest solution. Acquired lysosomal storage diseases can be caused by inorganic materials (iron, silicon, thorium, asbestos), macromolecules (polyvinylpyrrolidone) or micromolecules such as certain drugs (chloroquine, fenfluramine). Provided that administration of the causative agent is stopped before serious effects arise, acquired storage diseases can be considered reversible. However, irreversible pigmentary maculopathy can arise with prolonged drug administration.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Les urgences en ophtalmologie

1ère édition 2000-01/1MED5 et DES en médecine aiguë OFTA 005info:eu-repo/semantics/published

L'approche chirurgicale de la rétinopathie diabétique.

Progress in instrumentation and techniques may prevent from blindness patients affected with severe diabetic retinopathy. Surgery stabilizes the situation in 20% of the cases and improves vision in 70%. In 10% of the cases, however, treatment is undertaken too late and the eye may be lost. Although great improvements have been realized, early detection and screening for diabetic retinopathy, as well as adequate laser therapy, are of prime importance to save vision of diabetic patients.SCOPUS: ar.jinfo:eu-repo/semantics/publishe