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91.
We present an exposition of quadratic-residue codes through their embedding in codes over the quadratic subfield of the th cyclotomic field, the algebraic number field of th roots of unity. This representation allows the development of effective syndrome decoding algorithms that can fully exploit the code’s error-correcting capability. This is accomplished via Galois automorphisms of cyclotomic fields. For each fixed , the general results hold for all pairs , with a finite number of exceptions that depends on . A complete discussion of the set of quadratic-residue codes of length and dimension illustrates these results. This set includes the Golay code, the only perfect binary three-error-correcting code.A preliminary version of this paper was presented at the International Conference on Statistics, Combinatorics and Related Areas, October 3–5, 2003, University of Southern Maine, Portland, ME, USA. 相似文献
92.
We analytically predict the existence of both spatial bright and dark counterpropagating solitons in a reflection grating in the presence of the Kerr nonlinearity. The basic trapping mechanism consists of a twofold balance where diffraction is compensated by self-focusing and reflection is altered by the nonlinear-induced interferometric grating. We find that, whenever the spectral soliton profile lies within the grating stop band, bright and dark solitons exist only if the mutual phase of the counterpropagating solitons is pi or 0, respectively. 相似文献
93.
Elia Liitiäinen Francesco Corona Amaury Lendasse 《Journal of multivariate analysis》2010,101(4):811-823
In this paper we consider the problem of estimating E[(Y−E[Y∣X])2] based on a finite sample of independent, but not necessarily identically distributed, random variables . We analyze the theoretical properties of a recently developed estimator. It is shown that the estimator has many theoretically interesting properties, while the practical implementation is simple. 相似文献
94.
95.
Elia J.L. Stoffman 《Tetrahedron》2010,66(25):4452-4461
4-Chloro-, 4-bromo- and 4-iodoserotonin derivatives were synthesized from 4-halo-5-oxyindoles, themselves derived from coumarins. Synthesis of the 4-iodoserotonins involved conjugate addition of an allyl group to a 5-iodocoumarin, followed by conversion of the allyl group into an aminoethyl unit. One of the iodoserotonin derivatives was converted into the toad alkaloid dehydrobufotenine, which was isolated as its hydroiodide. 相似文献
96.
Rendiconti del Circolo Matematico di Palermo Series 1 - 相似文献
97.
A new transdermal delivery system that controls cellulitis is evaluated using reversed-phase high-performance liquid chromatography coupled with photodiode array detection. An extraction procedure and the validation of the analytical method to assay the active excipients from the Centella asiatica plant (asiaticoside, madacessic acid, and asiatic acid) are described. Excellent results ae obtained in terms of linearity, accuracy, and specificity of the analytical method. 相似文献
98.
Giuseppina Castronuovo Vittorio Elia Filomena Velleca 《Journal of solution chemistry》1996,25(10):971-982
Calorimetric measurements were carried out at 25°C on binary aqueous solutions containing N-acetyl derivatives of the following -amino acids: glycine, alanine, valine, leucine, norleucine, aspartic acid, glutamic acid, phenylalanine, methionine, asparagine, glutamine, cysteine, histidine, serine. The N-acetyl derivative of the -amino acid proline was also studied. The results obtained have been used to calculate the pairwise enthalpic interaction coefficients and these are compared with results reported in the literature concerning free -amino acids, and their acetylamide derivatives. The coefficients largely increase passing from free amino acids to N-acetyl derivatives. The derivatives of -amino acids bearing unsubstituted alkyl chains present an increased cooperativity of hydrophobic interactions. 相似文献
99.
Sabatini L Barbieri A Tosi M Roda A Violante FS 《Rapid communications in mass spectrometry : RCM》2005,19(2):147-152
8-Hydroxy-2'-deoxyguanosine (8OHdG), one of the major oxidative DNA lesions induced by radical agents, is commonly used as a biomarker for oxidative stress, nowadays preferably in urine. In the absence of a commercially available internal standard a micro-high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (micro-HPLC/ESI-MS/MS) method, suitable for routine analysis of 8OHdG in human urine using external calibration, was developed. Evaluation of the matrix effect showed that the method allows highly sensitive and accurate quantitation despite the absence of an internal standard. HPLC analysis was performed using gradient elution at a flow rate of 10 microL min(-1) using a capillary reversed-phase column and an injection volume of 0.5 microL, with detection of 8OHdG in positive multiple reaction monitoring (MRM) mode. The absolute limit of detection was 0.35 fmol using m/z 168 as a quantifier (fragment) ion. A linear (R2> 0.999) calibration curve in urine was obtained over a range 0.2-10 ng mL(-1). This method is about 20 times more sensitive than previously described procedures, and is characterized by high accuracy (mean 90%) and good reproducibility (RSD <10%). The optimized method was applied to determination of 8OHdG in 18 urinary samples derived from three healthy volunteers. 8OHdG urinary excretion ranged from 3.0-7.9 microg/day, and a large intra-individual variation was found. This method, which effectively circumvents the need for isotopically labeled 8OHdG (internal standard), is suitable for routine monitoring of exposure to DNA-damaging factors in a large number of subjects. 相似文献
100.
Angie?S?Mah Andrew?EH?Elia Geeta?Devgan Jason?Ptacek Mike?Schutkowski Michael?Snyder Michael?B?Yaffe Raymond?J?DeshaiesEmail author 《BMC biochemistry》2005,6(1):22