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61.
Alexandre Leblanc 《Annals of the Institute of Statistical Mathematics》2012,64(5):919-943
It is a known fact that some estimators of smooth distribution functions can outperform the empirical distribution function in terms of asymptotic (integrated) mean-squared error. In this paper, we show that this is also true of Bernstein polynomial estimators of distribution functions associated with densities that are supported on a closed interval. Specifically, we introduce a higher order expansion for the asymptotic (integrated) mean-squared error of Bernstein estimators of distribution functions and examine the relative deficiency of the empirical distribution function with respect to these estimators. Finally, we also establish the (pointwise) asymptotic normality of these estimators and show that they have highly advantageous boundary properties, including the absence of boundary bias. 相似文献
62.
Andrew Taylor Robert L. Jones Alain Leblanc Olav Mazarrasa Mi-Young Lee Patrick J. Parsons Marina Patriarca Jean-Philippe Weber Cas Weykamp 《Accreditation and quality assurance》2009,14(8-9):461-466
An under-recovery of inorganic mercury added to urine and a wide range of results is observed in quality assessment schemes (EQAS) for trace elements. Furthermore, the under-recoveries are inconsistent suggesting features associated with the urine matrix may make the mercury unavailable for measurement. To investigate the instability of mercury in urine the following experiments were set up: (1) a sample of Hg2+ in water with various ‘stabilizers’ added was sent to UK external quality assessment scheme participants. (2) Urine was collected from volunteers who also completed a 3-day food diary. Hg, Ca, Mg, Se, uric acid, phosphate, creatinine, reducing substances and protein were measured. Inorganic mercury was spiked into the urine, stabilizers were added and the mercury determined following storage. The results confirmed under-recovery of mercury in association with the urine matrix. Further investigations of how urinary components affect the measurement of mercury are necessary. 相似文献
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The nature of the interaction between adjacent chlorophyll a molecules in a mono- and multilayer is examined by infrared spectroscopy. The evidences suggest a different aggregation in the monolayer compared to the multilayer system. The monolayer state of chlorphylls may be a prerequisite to synthesize the energy trap in the photosynthetic unit. 相似文献
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Leblanc N Mercier N Zorina L Simonov S Auban-Senzier P Pasquier C 《Journal of the American Chemical Society》2011,133(38):14924-14927
The search for hybrid organic-inorganic materials, which have the great advantage that they can be synthesized at moderate temperature (T < 200 °C), remains a great challenge in the field of ferroelectrics. Here, a room-temperature ferroelectric material with interesting characteristics, (MV)[BiI(3)Cl(2)] (MV(2+) = methylviologen), is reported. Its structure is based on polar inorganic chains resulting from a remarkable Cl/I segregation induced by methylviologen entities, which coincide with the fourfold polar axis of the tetragonal structure. Of great importance is that this room-temperature hybrid ferroelectric displays a clear electrical hysteresis loop with a large spontaneous polarization (>15 μC·cm(-2)). 相似文献