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Search Results: 1 - 10 of 15139 matches for " Anna Petrov4 "
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Attitudes about science and conceptual physics learning in university introductory physics courses
Marina Milner-Bolotin1,Tetyana Antimirova2,Andrea Noack3,Anna Petrov4
Physical Review Special Topics. Physics Education Research , 2011,
Abstract: This paper examines the results of the repeated administration of the Colorado Learning Attitudes about Science Survey (CLASS) in a large introductory physics course at a midsize, metropolitan Canadian university. We compare the results to those obtained previously in comparable courses at the University of British Columbia (Canada) and the University of Colorado (U.S.). Atypically, students in this study exhibited a positive shift in their attitudes about science over the semester. The change in students’ attitudes across the term appears to be moderated by their educational background—specifically, whether they had taken grade 12 physics or not. The correlation between students’ attitudes and their conceptual knowledge also appears to be influenced by students’ educational background. The results have pedagogical implications for instructors of introductory college and university physics and potentially for other science courses.
On possible growth of Toeplitz languages
Julien Cassaigne,Anna Frid,Fedor Petrov
Mathematics , 2010,
Abstract: We consider a new family of factorial languages whose subword complexity grows as $\Theta(n^{\alpha})$, where $\alpha$ is the root of some transcendent equation. Analytical methods and in particular, a corollary of the Wiener-Pitt theorem, are used to find the asymptotic growth of the complexity. Factorial languages considered are languages of arithmetical factors of some Toeplitz words. So, we describe a new family of words with an unusual growth of arithmetical complexity.
Frequency of Juvenile Myoclonic Epilepsy Clinical Phenotypes in Siberia  [PDF]
Olga S. Shilkina, Kirill A. Petrov, Anna V. Diuzhakova, Natalia A. Marueva, Natalia A. Shnayder
World Journal of Neuroscience (WJNS) , 2016, DOI: 10.4236/wjns.2016.61004
Abstract: Juvenile myoclonic epilepsy (JME) is characterised by myoclonia during awakening, generalised tonic-clonic seizures, typical absences and usually presents for the first time at the age of 12 to 18 years old. This article describes the results of a clinical study into JME phenotypes in patients living in the Siberian Federal District. We have shown that the incidence of JME among males was lower than among females (1:1.9) and JME debut age for males was higher than in those women. Classical phenotype of JME (Type I) was dominant and more common in males compared to females—70.4% vs. 58.5%, respectively. The JME phenotype with worse prognosis in terms of achieving stable clinical remission (Type II) occurred 3.5 times more frequently among female patients compared to male (13.2% vs. 3.7% respectively). The findings resulting from this study give a deeper insight into the diagnosis and prognosis of this form of idiopathic generalised epilepsy in predisposed families.
Mean-Value Theorems for Harmonic Functions on the Cube in Rn  [PDF]
Petar Petrov
Advances in Pure Mathematics (APM) , 2015, DOI: 10.4236/apm.2015.511062
Abstract: Let \"\"be a hypercube in Rn. We prove theorems concerning mean-values of harmonic and polyharmonic functions on In(r), which can be considered as natural analogues of the famous Gauss surface and volume mean-value formulas for harmonic functions on the ball in and their extensions for polyharmonic functions. We also discuss an application of these formulas—the problem of best canonical one-sided L1-approximation by harmonic functions on In(r).
Genome Patterns of Selection and Introgression of Haplotypes in Natural Populations of the House Mouse (Mus musculus)
Fabian Staubach,Anna Lorenc,Philipp W. Messer,Kun Tang,Dmitri A. Petrov,Diethard Tautz
PLOS Genetics , 2012, DOI: 10.1371/journal.pgen.1002891
Abstract: General parameters of selection, such as the frequency and strength of positive selection in natural populations or the role of introgression, are still insufficiently understood. The house mouse (Mus musculus) is a particularly well-suited model system to approach such questions, since it has a defined history of splits into subspecies and populations and since extensive genome information is available. We have used high-density single-nucleotide polymorphism (SNP) typing arrays to assess genomic patterns of positive selection and introgression of alleles in two natural populations of each of the subspecies M. m. domesticus and M. m. musculus. Applying different statistical procedures, we find a large number of regions subject to apparent selective sweeps, indicating frequent positive selection on rare alleles or novel mutations. Genes in the regions include well-studied imprinted loci (e.g. Plagl1/Zac1), homologues of human genes involved in adaptations (e.g. alpha-amylase genes) or in genetic diseases (e.g. Huntingtin and Parkin). Haplotype matching between the two subspecies reveals a large number of haplotypes that show patterns of introgression from specific populations of the respective other subspecies, with at least 10% of the genome being affected by partial or full introgression. Using neutral simulations for comparison, we find that the size and the fraction of introgressed haplotypes are not compatible with a pure migration or incomplete lineage sorting model. Hence, it appears that introgressed haplotypes can rise in frequency due to positive selection and thus can contribute to the adaptive genomic landscape of natural populations. Our data support the notion that natural genomes are subject to complex adaptive processes, including the introgression of haplotypes from other differentiated populations or species at a larger scale than previously assumed for animals. This implies that some of the admixture found in inbred strains of mice may also have a natural origin.
The Crystal and Molecular Structure of (2Z)-2-[3-(4-Methoxybenzoyl)-4,4-dimethyl-1,2-oxazolidin-2-ylidene]-1-(4-methoxyphenyl)ethanone
Anna Petrov,Roderick C. Jones,Douglas G. Vaughan,Alan J. Lough,Robert A. Gossage
Crystals , 2011, DOI: 10.3390/cryst1040229
Abstract: The crystal and molecular structure of the title compound, viz., ( 2Z)-2-[3-(4-methoxybenzoyl)-4,4-dimethyl-1,2,-oxazolidin-2-ylidene]-1-(4-methoxyphenyl)ethanone ( 4), is reported. Compound 4 crystallises from toluene/hexanes mixtures in the P2 1/c space group with eight molecules in the unit cell. The unit cell parameters are: a = 20.9410(11) ?, b = 8.7523(5) ?, c = 21.2291(9) ?; β = 93.529(3)° and V = 3883.5(3) ? 3. There are two structurally distinct molecules of 4 found in the solid-state which differ primarily in terms of the observed torsion angles and the overall intramolecular spacing between the aromatic groups. Bond lengths and angles of this tertiary amide are otherwise typical. This is the first crystallographically characterised example of this class of oxazoline precursors, which have previously found application in the syntheses of other heterocycles. Density functional theory (b3lyp 6-311++G** level of sophistication) has likewise been applied to estimate the gas-phase structure of the title compound.
Effect of structure parameters and composition of high-silica porous glasses on their thermal and radiation resistant properties
Tatiana V. Antropova,Anna V. Volkova,Dmitry V. Petrov,Sergei V. Stolyar
Optica Applicata , 2005,
Abstract: The influence of a composition of initial phase-separated alkali borosilicate glass and its thermal treatment as well leaching conditions on the parameters of the porous glass structure are discussed. The results obtained by adsorption and conductivity methods, transmission electron microscopy and dilatometer technique were used to analyse the effect of structure parameters and composition of high-silica porous glasses on their thermal and radiation resistant properties.
Information Interpretation of Heisenberg Uncertainty Relation  [PDF]
Oleg V. Petrov
Optics and Photonics Journal (OPJ) , 2019, DOI: 10.4236/opj.2019.92002
Abstract: In this paper the following information interpretation of uncertainty relation is proposed: if one bit of information was extracted from the system as a result of the measurement process, then the measurement itself adds an additional uncertainty (chaos) into the system equaled to one bit. This formulation is developed by calculating of the Shannon information entropy for the classical N-slit interference experiment. This approach allows looking differently at several quantum phenomena. Particularly, the information interpretation is used for explanation of entangled photons diffraction picture compression.
GT 4
Revista Brasileira de Ecoturismo , 2012,
Abstract: O desenvolvimento de atividades turísticas no espa o rural está associado ao processo de urbaniza o que ocorre na sociedade e no transbordamento do espa o urbano para o espa o rural e, neste sentido, "novas" formas de ocupa o passaram a proliferar no campo. Destarte, o objetivo deste eixo temático é o de analisar o turismo rural e, como ele vem desempenhando papel importante no processo de transforma o desse espa o, como novas re-significa es, além de conhecer as características das abordagens da produ o familiar e suas estratégias de sobrevivência, sejam através de empregos agrícolas ou n o-agrícolas, processos fundamentais para o desenvolvimento do turismo com base local. Coordena o: Profa. Dra. Maria Geralda de Almeida (UFG) e Profa. Dra. Marlene Huebes Novais (UNIVALI), Prof. Dr. Giovanni de Farias Seabra (UFPB)
Resonant mesomolecule formation
Yu. Petrov,V. Petrov
Physics , 2001,
Abstract: The dtm and ddm resonant fusion rates are calculated taking into account finite resonance width and subthreshold resonances. Calculations do not use multipole expansion of the potential. The obtained ddm resonant fusion rates are compared with recent data at 30-360 K.
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