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1.
Most of the methods used in the ARCH literature for selecting the appropriate model are based on evaluating the ability of the models to describe the data. An alternative model selection approach is examined based on the evaluation of the predictability of the models in terms of standardized prediction errors. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
2.
It can be conjectured that the colored Jones function of a knot can be computed in terms of counting paths on the graph of
a planar projection of a knot. On the combinatorial level, the colored Jones function can be replaced by its weight system.
We give two curious formulas for the weight system of a colored Jones function: one in terms of the permanent of a matrix
associated to a chord diagram, and another in terms of counting paths of intersecting chords.
Electronic supplementary material to this article is available at and is accessible to authorized users.
* S. G. was partially supported by an NSF and by an Israel-US BSF grant.
† M. L. was partly supported by GAUK 158 grant and by the Project LN00A056 of the Czech Ministry of Education. 相似文献
3.
We study the approximability of minimum total weighted tardiness with a modified objective which includes an additive constant. This ensures the existence of a positive lower bound for the minimum value. Moreover the new objective has a natural interpretation in just-in-time production systems. 相似文献
4.
Smith RA Verlet JR Boleat ED Stavros VG Fielding HH 《Faraday discussions》2000,(115):63-70; discussion 79-102
Rydberg electron wavepackets have been studied in molecular NO for a variety of rotational states of the ion core. Predominantly radial motion of the electron wavepacket is observed which is similar to that previously reported in atomic systems. Interference effects similar to those observed in unperturbed Rydberg series are evident and third and fourth order partial revivals are identified. Most interestingly, when the classical period of electronic motion is close to the classical period of rotation of the molecular ion, the molecular dynamics dominates the electronic dynamics. 相似文献
5.
A number of thiosemicarbazones of 2‐acetyl‐imidazo[4,5‐b]pyridine were prepared in order to investigate their in vitro antineoplastic activities. Three compounds: (i) 2‐acetylimidazo[4,5‐b]pyridin‐4‐ sec ‐butyl‐3‐thiosemicarbazone [(A7), NSC674098], (ii) 2‐acetylimidazo[4,5‐b]pyridin‐4‐tert‐butyl‐3‐thiosemi‐carbazone [(A9), NSC674099], (iii) 2‐acetylimidazo[4,5‐b]pyridin‐4‐cyclohexyl‐3‐thiosemicarbozone [(A11), NSC674101] showed remarkable activity against some of the cell lines tested. The Biological Evaluation Committee of N.C.I. determined that further secondary testing should be carried out (these compounds were tested against prostate cancer). 相似文献
6.
Corma A Diaz-Cabanas MJ Rey F Nicolopoulus S Boulahya K 《Chemical communications (Cambridge, England)》2004,(12):1356-1357
The pore topology of ITQ-15 zeolite consists of an ultra-large 14-ring channel that is intersected perpendicularly by a 12-ring pore; acid sites have been introduced in its framework and this unique structure shows advantages over unidirectional ultralarge pore zeolites for diffusing and reacting large molecules. 相似文献
7.
Nikolaos C. Papandreou Stella Makedonopoulou Ekaterini A. Antoniadou‐Vyza Irene M. Mavridis Stavros J. Hamodrakas 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(12):o730-o732
The title salt, C18H22N5+·Cl?, is a member of a new series of lipophilic 4,6‐diamino spiro‐s‐triazines which are potent inhibitors of dihydrofolate reductase. The protonated triazine ring deviates from planarity, whereas the cyclohexane ring adopts a chair conformation. A rather unusual hydrogen‐bonding scheme exists in the crystal. There is a centrosymmetric arrangement involving two amino groups and two triazine ring N atoms, with graph‐set R(8) and an N?N distance of 3.098 (3) Å, flanked by two additional R(8) systems, involving two amino groups, a triazine ring N atom and a Cl? anion, with N?Cl distances in the range 3.179 (2)–3.278 (2) Å. Furthermore, the Cl? anion, the protonated triazine ring N atom and an amino group form a hydrogen‐bonding system with graph‐set R(6). 相似文献
8.
We prove several improved versions of Bohr’s inequality for the harmonic mappings of the form , where is bounded by 1 and . The improvements are obtained along the lines of an earlier work of Kayumov and Ponnusamy, i.e. (Kayumov and Ponnusamy, 2018) for example a term related to the area of the image of the disk under the mapping is considered. Our results are sharp. In addition, further improvements of the main results for certain special classes of harmonic mappings are provided. 相似文献
9.
10.
Evangelos Gikas Nikolaos Stavros Koulakiotis Anthony Tsarbopoulos 《Molecules (Basel, Switzerland)》2021,26(8)
The metabolite profiling of saffron (Crocus sativus L.) from several countries was measured by using ultra-performance liquid chromatography combined with high resolution mass spectrometry (UPLC-HR MS). Multivariate statistical analysis was employed to distinguish among the several samples of C. sativus L. from Greece, Italy, Morocco, Iran, India, Afghanistan and Kashmir. The results of this study showed that the phytochemical content in the samples of C. sativus L. were obviously diverse in the different countries of origin. The metabolomics approach was deemed to be the most suitable in order to evaluate the enormous array of putative metabolites among the saffron samples studied, and was able to provide a comparative phytochemical screening of these samples. Several markers have been identified that aided the differentiation of a group from its counterparts. This can be important for the selection of the appropriate saffron sample, in view of its health-promoting effect which occurs through the modulation of various biological and physiological processes. 相似文献