Mécanismes de recuit dans le silicium implanté par faisceau d’ion caractérisés par nanocalorimétrie

Nous présenterons le procédé de fabrication, la caractérisation, ainsi qu’un modèle numérique permettant l’optimisation d’un nouveau dispositif permettant d’effectuer des mesures de nanocalorimétrie sur un échantillon de silicium monocristallin. Ce dernier possède entre autre des propriétés thermiques nous permettant d’effectuer des mesures à des températures supérieures à 900 C, avec une résolution meilleure que 16 C. Ceci nous a permis d’étudier la dynamique des défauts induits par implantation ionique dans le silicium monocristallin. Deux comportements différents sont observés dans la germination de la phase amorphe induite par implantation à 10 et 80 keV. Ces résultats ont été confrontés à des simulations Monte-Carlo basées sur le modèle des paires lacunesinterstitiels. La comparaison entre les simulations et les mesures expérimentales ont montré que ce modèle est incomplet car il ne reproduit qualitativement que certaines caractéristiques observées expérimentalement. Des mesures réalisées à partir de -110 C dans le silicium monocristallin et amorphisé implanté avec des ions légers, ont mis en évidence des différences claires entre la relaxation dans le silicium amorphe et le recuit des défauts dans le silicium monocristallin. Deux processus à des énergies d’activation de 0.48 et 0.6 eV ont été observés pour les implantations réalisées dans le silicium monocristallin tandis qu’un relâchement de chaleur uniforme ne révélant qu’un spectre continu d’énergie d’activation a été observé dans le silicium amorphe.

Sparse one-dimensional discrete Dirac operators II: Spectral properties

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Espectro de Polariton de Plasmons e Ondas de Luz em Quasi-Cristais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Análise molecular de pacientes com holoprosencefalia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise molecular de pacientes com holoprosencefalia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Coherent states and related quantizations for unbounded motions

We discuss the construction of coherent states (CS) for systems with continuous spectra. First, we propose to adopt the Malkin-Manko approach, developed for systems with discrete spectra, to the case under consideration. Following this approach, we consider two examples, a free particle and a particle in a linear potential. Second, we generalize the approach of action-angle CS to systems with continuous spectra. In the first approach we start with a well-defined quantum formulation (canonical quantization) of a physical system and the construction of CS follows from such a quantization. In the second approach, the quantization procedure is inherent to the CS construction itself.

Protocol for a population-based study of rheumatic heart disease prevalence and cardiovascular outcomes among schoolchildren in Nepal

Rheumatic heart disease (RHD) remains a major contributor to morbidity and mortality in developing countries. The reported prevalence rates of RHD are highly variable and mainly attributable to differences in the sensitivity of either clinical screening to detect advanced heart disease or echocardiographic evaluation where disease is diagnosed earlier across a continuous spectrum. The clinical significance of diagnosis of subclinical RHD by echocardiographic screening and early implementation of secondary prevention has not been clearly established. METHODS AND ANALYSIS: The authors designed a cross-sectional survey to determine the prevalence of RHD in children from private and public schools between the age of 5 and 15 years in urban and rural areas of Eastern Nepal using both cardiac auscultation and echocardiographic evaluation. Children with RHD will be treated with secondary prevention and enrolled in a prospective cohort study. The authors will compare the prevalence rates by cardiac auscultation and echocardiography, determine risk factors associated with diagnosis and progression of RHD, investigate social and economic barriers for receiving adequate cardiac care and assess clinical outcomes with regular medical surveillance as a function of stage of disease at the time of diagnosis. Prospective clinical studies investigating the impact of secondary prevention for subclinical RHD on long-term clinical outcome will be of central relevance for future health resource utilisation in developing countries. ETHICS AND DISSEMINATION: The study was considered ethically uncritical and was given an exempt status by the ethics committee at University of Bern, Switzerland. The study has been submitted to the National Nepal Health Research Council and was registered with http://www.ClinicalTrials.gov (NCT01550068). The study findings will be reported in peer-reviewed publications. CLINICALTRIALS.GOV IDENTIFIER: NCT01550068.

Image analysis of immunohistochemistry is superior to visual scoring as shown for patient outcome of esophageal adenocarcinoma.

Quantification of protein expression based on immunohistochemistry (IHC) is an important step in clinical diagnoses and translational tissue-based research. Manual scoring systems are used in order to evaluate protein expression based on staining intensities and distribution patterns. However, visual scoring remains an inherently subjective approach. The aim of our study was to explore whether digital image analysis proves to be an alternative or even superior tool to quantify expression of membrane-bound proteins. We analyzed five membrane-binding biomarkers (HER2, EGFR, pEGFR, β-catenin, and E-cadherin) and performed IHC on tumor tissue microarrays from 153 esophageal adenocarcinomas patients from a single center study. The tissue cores were scored visually applying an established routine scoring system as well as by using digital image analysis obtaining a continuous spectrum of average staining intensity. Subsequently, we compared both assessments by survival analysis as an end point. There were no significant correlations with patient survival using visual scoring of β-catenin, E-cadherin, pEGFR, or HER2. In contrast, the results for digital image analysis approach indicated that there were significant associations with disease-free survival for β-catenin, E-cadherin, pEGFR, and HER2 (P = 0.0125, P = 0.0014, P = 0.0299, and P = 0.0096, respectively). For EGFR, there was a greater association with patient survival when digital image analysis was used compared to when visual scoring was (visual: P = 0.0045, image analysis: P < 0.0001). The results of this study indicated that digital image analysis was superior to visual scoring. Digital image analysis is more sensitive and, therefore, better able to detect biological differences within the tissues with greater accuracy. This increased sensitivity improves the quality of quantification.

Colored dissolved organic matter (cDOM) absorption measurements in Antarctic lakes

The datasets present measurements of cDOM absorption of lakes located in Antarctic oasis during the summer periods from 2013 to 2016. In summer season of 2013 water samples were collected on Fildes Peninsula (King George Island, West Antarctica) - Bellingshausen Station, Russia. Investigated lakes on Fides Peninsula were completely or partly free from ice cover during water sampling. In summer seasons of 2014-2016 water samples were collected on Vestfold Hills, Reuer Island and Larsemann Hills Oasis (East Antarctica) - Progress station, Russia. During 2014-2016 summer season part of lakes on Larsemann Hills Oasis were free from ice cover, some of the lakes were completely covered by ice and were drilled before sampling. Part of the water samples from Progress Station (2015) has not been filtered. cDOM is operationally defined by the chosen filter pore size. Samples have been consistently filtrated through 0.7 µm pore size glas fibre filters. cDOM filtrates have been stored in darkness and have been measured after the expedition using the dual-beam Specord200 laboratory spectrometer (Jena Analytik) at the Otto Schmidt Laboratory OSL, Arctic and Antarctic Research Institute, St. Petersburg, Russia. The OSL cDOM protocol (Heim and Roessler, 2016) prescribes 3 Absorbance (A) measurements per sample from UV to 750 nm against ultra-pure water. The absorption coefficient, a, is calculated by a = 2.303A/L, where L is the pathlength of the cuvette [m], and the factor 2.303 converts log10 to loge. The output of the calculation is a continuous spectrum of a. The cDOM a spectra are used to determine the exponential slope value for specific wavelength ranges, S by fitting the data between min and max wavelength to an exponential function. We provide cDOM absorption coefficients for the wavelengths 254, 260, 350, 375, 400, 412, 440, 443 nm [1/m] and Slope values for three different UV, VIS, wavelength ranges: 275 to 295 nm, 350 to 400 nm, 300 to 500 nm [1/nm]. All data were carried out by scientists from Arctic and Antarctic Research Institute and Saint Petersburg State University of Russia during Russian Antarctic Expedition in 2013-2016.

Calcium carbonate, isotopes and Rock-Eval pyrolysis at DSDP Holes 77-535 and 77-540

At DSDP Sites 534 (Central Atlantic) and 535 and 540 (Gulf of Mexico), and in the Vocontian Basin (France), Lower Cretaceous deposits show a very pronounced alternation of limestone and marl. This rhythm characterizes the pelagic background sedimentation and is independent of detritic intercalations related to contour and turbidity currents. Bed-scale cycles, estimated to be 6000-26,000 yr. long, comprise major and minor units. Their biological and mineralogic components, burrowing, heavy isotopes C and O, and some geochemical indicators, vary in close correlation with CaCO3 content. Vertical changes of frequency and asymmetry of the cycles are connected with fluctuations of the sedimentation rate. Plots of cycle thickness ("cyclograms") permit detailed correlations of the three areas and improve the stratigraphic subdivision of Neocomian deposits at the DSDP sites. Small-scale alternations, only observed in DSDP cores, comprise centimetric to millimetric banding and millimetric to micrometric lamination, here interpreted as varvelike alternations between laminae that are rich in calcareous plankton and others rich in clay. The laminations are estimated to correspond to cycles approximately 1,3, and 13 yr. in duration. The cyclic patterns appear to be governed by an interplay of continental and oceanic processes. Oceanic controls express themselves in variations of the biogenic carbonate flux, which depends on variations of such elements as temperature, oxygenation, salinity, and nutrient content. Continental controls modulate the influxes of terrigenous material, organic matter, and nutrients derived from cyclic erosion on land. Among the possible causes of cyclic sedimentation, episodic carbonate dissolution has been ruled out in favor of climatic fluctuations with a large range of periods. Such fluctuations are consistent with the great geographic extension shown by alternation controls and with the continuous spectrum of scales that characterizes limestone-marl cycles. The climatic variations induced by the Earth's orbital parameters (Milankovitch cycles) could be connected to bed-interbed alternations.

Colored dissolved organic matter (cDOM) absorption measurements in terrestrial water objects of Yamal, Yavai and Gydan Peninsula

The datasets present measurements of cDOM absorption in lakes, rivers and streams of Yamal and Gydan Peninsula area during the summer periods from 2012-2014 and 2016. In summer seasons of 2012 - 2013 water samples was collected during "Yamal-Arctic" Expedition. All of the research areas were located near the coastline of Yamal, Yavay, and Gydan Peninsula and Bely Island. In 2012 water samples from rivers, lakes and streams were taken near New Port, Cape Kamenny and Tambey settlements and in basins (water catchments) of the Sabetta, Seyakha, Yuribey (Baydaratskaya Bay, Gydan Peninsula) and Mongocheyakha rivers. In 2013 water samples from rivers, lakes and streams were taken in the Yavai Peninsula, Yayne Vong bay and in the basins (water catchments) of the Sabetta, Mongocheyakha and Yuribey (Gydan Peninsula) rivers. In 2014 lakes were sampled in the Erkuta River basin, south of Yamal Peninsula. In 2016 lakes and rivers were sampled it the Erkuta River basin and Polar Ural area. cDOM is operationally defined by the chosen filter pore size. Samples have been consistently filtrated through 0.7 µm pore size glas fibre filters. cDOM filtrates have been stored in darkness and have been measured after the expedition using the dual-beam Specord200 laboratory spectrometer (Jena Analytik) at the Otto Schmidt Laboratory OSL, Arctic and Antarctic Research Institute, St. Petersburg, Russia. The OSL cDOM protocol (Heim and Roessler, 2016) prescribes 3 Absorbance (A) measurements per sample from UV to 750 nm against ultra-pure water. The absorption coefficient, a, is calculated by a = 2.303A/L, where L is the pathlength of the cuvette [m], and the factor 2.303 converts log10 to loge. The output of the calculation is a continuous spectrum of a. The cDOM a spectra are used to determine the exponential slope value for specific wavelength ranges, S by fitting the data between min and max wavelength to an exponential function. We provide cDOM absorption coefficients for the wavelengths 254, 260, 350, 375, 400, 412, 440, 443 nm [1/m] and Slope values for three different UV, VIS, wavelength ranges: 275 to 295 nm, 350 to 400 nm, 300 to 500 nm [1/m]. All data were carried out by scientists from Arctic and Antarctic Research Institute and Saint Petersburg State University of Russia during "Yamal-Arctic" expeditions in 2012-2013, RFBR project No 14-04-10065 in 2014, No 14-05-00787 in 2016.

Molecular classification of cutaneous malignant melanoma by gene expression profiling

The most common human cancers are malignant neoplasms of the skin(1,2). Incidence of cutaneous melanoma is rising especially steeply, with minimal progress in non-surgical treatment of advanced disease(3,4). Despite significant effort to identify independent predictors of melanoma outcome, no accepted histopathological, molecular or immunohistochemical marker defines subsets of this neoplasm(2,3). Accordingly, though melanoma is thought to present with different 'taxonomic' forms, these are considered part of a continuous spectrum rather than discrete entities(2). Here we report the discovery of a subset of melanomas identified by mathematical analysis of gene expression in a series of samples. Remarkably, many genes underlying the classification of this subset are differentially regulated in invasive melanomas that form primitive tubular networks in vitro, a feature of some highly aggressive metastatic melanomas(5). Global transcript analysis can identify unrecognized subtypes of cutaneous melanoma and predict experimentally verifiable phenotypic characteristics that may be of importance to disease progression.

Dynamical Resonances and SSF Singularities for a Magnetic Schrödinger Operator

We consider the Hamiltonian H of a 3D spinless non-relativistic quantum particle subject to parallel constant magnetic and non-constant electric field. The operator H has infinitely many eigenvalues of infinite multiplicity embedded in its continuous spectrum. We perturb H by appropriate scalar potentials V and investigate the transformation of these embedded eigenvalues into resonances. First, we assume that the electric potentials are dilation-analytic with respect to the variable along the magnetic field, and obtain an asymptotic expansion of the resonances as the coupling constant ϰ of the perturbation tends to zero. Further, under the assumption that the Fermi Golden Rule holds true, we deduce estimates for the time evolution of the resonance states with and without analyticity assumptions; in the second case we obtain these results as a corollary of suitable Mourre estimates and a recent article of Cattaneo, Graf and Hunziker [11]. Next, we describe sets of perturbations V for which the Fermi Golden Rule is valid at each embedded eigenvalue of H; these sets turn out to be dense in various suitable topologies. Finally, we assume that V decays fast enough at infinity and is of definite sign, introduce the Krein spectral shift function for the operator pair (H+V, H), and study its singularities at the energies which coincide with eigenvalues of infinite multiplicity of the unperturbed operator H.

Dispersive estimates for the Schrödinger equation

In this document we explore the issue of $L^1\to L^\infty$ estimates for the solution operator of the linear Schr\"{o}dinger equation, \begin{align*} iu_t-\Delta u+Vu&=0 &u(x,0)=f(x)\in \mathcal S(\R^n). \end{align*} We focus particularly on the five and seven dimensional cases. We prove that the solution operator precomposed with projection onto the absolutely continuous spectrum of $H=-\Delta+V$ satisfies the following estimate $\|e^{itH} P_{ac}(H)\|_{L^1\to L^\infty} \lesssim |t|^{-\frac{n}{2}}$ under certain conditions on the potential $V$. Specifically, we prove the dispersive estimate is satisfied with optimal assumptions on smoothness, that is $V\in C^{\frac{n-3}{2}}(\R^n)$ for $n=5,7$ assuming that zero is regular, $|V(x)|\lesssim \langle x\rangle^{-\beta}$ and $|\nabla^j V(x)|\lesssim \langle x\rangle^{-\alpha}$, $1\leq j\leq \frac{n-3}{2}$ for some $\beta>\frac{3n+5}{2}$ and $\alpha>3,8$ in dimensions five and seven respectively. We also show that for the five dimensional result one only needs that $|V(x)|\lesssim \langle x\rangle^{-4-}$ in addition to the assumptions on the derivative and regularity of the potential. This more than cuts in half the required decay rate in the first chapter. Finally we consider a problem involving the non-linear Schr\"{o}dinger equation. In particular, we consider the following equation that arises in fiber optic communication systems, \begin{align*} iu_t+d(t) u_{xx}+|u|^2 u=0. \end{align*} We can reduce this to a non-linear, non-local eigenvalue equation that describes the so-called dispersion management solitons. We prove that the dispersion management solitons decay exponentially in $x$ and in the Fourier transform of $x$.

High-Rate Vector Quantization for Noisy Channels With Applications to Wideband Speech Spectrum Compression

This paper considers the high-rate performance of source coding for noisy discrete symmetric channels with random index assignment (IA). Accurate analytical models are developed to characterize the expected distortion performance of vector quantization (VQ) for a large class of distortion measures. It is shown that when the point density is continuous, the distortion can be approximated as the sum of the source quantization distortion and the channel-error induced distortion. Expressions are also derived for the continuous point density that minimizes the expected distortion. Next, for the case of mean squared error distortion, a more accurate analytical model for the distortion is derived by allowing the point density to have a singular component. The extent of the singularity is also characterized. These results provide analytical models for the expected distortion performance of both conventional VQ as well as for channel-optimized VQ. As a practical example, compression of the linear predictive coding parameters in the wideband speech spectrum is considered, with the log spectral distortion as performance metric. The theory is able to correctly predict the channel error rate that is permissible for operation at a particular level of distortion.