958 research outputs found

    Fundamental Limits of "Ankylography" due to Dimensional Deficiency

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    Single-shot diffractive imaging of truly 3D structures suffers from a dimensional deficiency and does not scale. The applicability of "ankylography" is limited to objects that are small-sized in at least one dimension or that are essentially 2D otherwise.Comment: 2 pages, no figur

    Metal-ligand bonding in six-coordinate d-block complexes probed by luminescence spectroscopy at variable pressure

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    Luminescence spectra measured at variable pressure can reveal unique insight on ground- and emitting state properties of transition metal compounds. This chapter summarizes illustrative results for chromium(III) complexes with the d3 electron configuration and oxo complexes of rhenium(V) and molybdenum(IV) with the d2 configuration. Their luminescence transitions only involve electronic configuration changes within the t2 (O point group) molecular orbitals, leading to narrow spin-flip bands and broad bands with vibronic structure for the chromium(III) and metal-oxo complexes, respectively

    A rare case of successful reproductive outcome after IVF following endometrioma resection in a patient of arcuate uterine anomaly and urinary bladder wall endometrioma in women with primary infertility

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    Endometriosis is a common gynecologic disease in women of reproductive age. However, endometriosis within the bladder is rare. We present a rare case of a 38-year-old woman who presented with dysmenorrhea and primary infertility. Transvaginal ultrasonography showed an arcuate bulky adenomyotic uterus and left ovarian cystic mass along with urinary bladder endometrioma. Cystoscopic examination was done and removal of endometrioma was attempted, which failed. Afterwards laparoscopic exploration of abdomen was done and a partial cystectomy was performed and it was confirmed that the mass on the bladder wall was a 3.5 cm endometrioma invading the vesical wall on the final pathologic report. Post-operatively, she underwent in vitro fertilization due to both causes i.e. primary infertility and male factor (severe oligo-asthenospermia) and she conceived. We report this case of a patient with primary infertility and bladder endometriosis which was managed successfully with a surgical approach and briefly review the relevant literature

    Le principe de précaution et l'exemple des champs électromagnétiques

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    Substance misuse in youth admitted to a psychiatric emergency unit

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    Objectives. To investigate the pattern of substance misuse in youth admitted to a psychiatric emergency unit of a 'major hospital, and to compare regular users of cannabis,methaqualone and alcohol with the rest of the sample in terms of selected psychosocial variables.Study population. Consecutive patients aged 25 years or younger admitted to a psychiatric emergency unit over a 3month period.Method. Patients completed a standardised questionnaire .containing questions about their family, social, economic and educational backgrounds. Their current psychiatric folder was examined to ascertain mental state and behaviour on admission as well as previous psychiatric contacts and hospitalisation. Particular attention was paid to the use of cannabis, methaqualone and alcohol For each substance patients were divided into two groups, namely those who did not use the substance or who used it infrequently, and regular users. Unadjusted odds ratios were used to document the relationship between substance use and the selected psychosocial variablesResults. One hundred and fourteen patients were assessed, of which number 61 (53.5%) were male and 98 (86%) were single. The group consisted of 37 blacks (32.5%), 56 coloureds (49.1%) and 21 whites (18.4%)_ Alcohol was . regularly used by 30 patients (263%), cannabis by 29 (25.4%), methaqualone by 11 (9.6%), and any-of these substances by 46 patients (40.4%). Unadjusted odds ratios showed that there was a significant association between regular use of alcohol and cannabis and male gender, dropping out of school, previous psychiatric treatment, and an absence of both depression and suicidal ideation; and between regular cannabis use and bizarre behaviour, auditory hallucinations and disorganised or incoherent speech. Methaqualone use was associated with hostile threats.Conclusions. In the study population substance use was associated with various adverse psychosocial circumstances; these may alert the practitioner to the possibility of substance use. Cannabis misuse was suggested by behavioural, perceptual and speech abnormalities on mental state examination

    Lattice Gas Automata for Reactive Systems

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    Reactive lattice gas automata provide a microscopic approachto the dynamics of spatially-distributed reacting systems. After introducing the subject within the wider framework of lattice gas automata (LGA) as a microscopic approach to the phenomenology of macroscopic systems, we describe the reactive LGA in terms of a simple physical picture to show how an automaton can be constructed to capture the essentials of a reactive molecular dynamics scheme. The statistical mechanical theory of the automaton is then developed for diffusive transport and for reactive processes, and a general algorithm is presented for reactive LGA. The method is illustrated by considering applications to bistable and excitable media, oscillatory behavior in reactive systems, chemical chaos and pattern formation triggered by Turing bifurcations. The reactive lattice gas scheme is contrasted with related cellular automaton methods and the paper concludes with a discussion of future perspectives.Comment: to appear in PHYSICS REPORTS, 81 revtex pages; uuencoded gziped postscript file; figures available from [email protected] or [email protected]

    Solution périodique et solution anti-périodique de l'équation différentielle d'Abel

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    Soit TT une constante positive. Dans le présent travail, nous nous intéressons à l'existence d'une solution TT-anti-périodique et d'une solution TT-périodique de l'équation différentielle d'Abel \begin{equation*} \theta^{\prime}=f_0+\sum_{j\in \mathbb N} f_j\theta^j \end{equation*} avec fjf_j, (j∈{0,1,2,...}j \in \lbrace 0, 1, 2, ...\rbrace) à variation bornée sur [0,T][0, T]. Nous allons généraliser cette équation au cas impulsif où θ\theta et θ′\theta^{\prime} subissent des sauts dépendants de l'état. Le premier chapitre consiste en un rappel de quelques définitions, notions de bases et résultats fondamentaux de l'analyse réelle et fonctionnelle que nous allons utiliser tout au long des chapitres 2 et 3. Au deuxième chapitre, on étudie l'existence d'une solution TT-anti-périodique dans le sens que θ(0)=−θ(T)\theta(0)= -\theta(T). Les conditions que nous imposons nous permettent d'utiliser le théorème du point fixe de Banach. Cette méthode nous donne non seulement l'existence d'une solution, mais aussi un moyen de trouver la solution numériquement ainsi qu'une majoration de la vitesse de convergence uniforme, d'une suite d'itérations de Picard vers la solution. Les résultats obtenus dans ce chapitre sont publiés dans \cite{BelleyGueye17}. Au troisième chapitre, on étudie l'existence d'une solution T-périodique pour la même équation. On utilise encore le théorème du point fixe de Banach pour garantir l'unicité de la solution. L'unicité est nécessaire pour que la fonction moyenne M(μ)M(\mu) que nous introduirons plus tard soit bien définie. Cette méthode nous donne également, non seulement l'existence d'une solution, mais aussi un moyen de trouver la solution numériquement ainsi qu'une majoration de la vitesse de convergence uniforme d'une suite d'itérations de Picard, vers la solution

    Coupling of thermal and mass diffusion in regular binary thermal lattice-gases

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    We have constructed a regular binary thermal lattice-gas in which the thermal diffusion and mass diffusion are coupled and form two nonpropagating diffusive modes. The power spectrum is shown to be similar in structure as for the one in real fluids, in which the central peak becomes a combination of coupled entropy and concentration contributions. Our theoretical findings for the power spectra are confirmed by computer simulations performed on this model.Comment: 5 pages including 3 figures in RevTex
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