810 research outputs found
Maternal repair system- an analysis in retrospect
Influence of caffeine, cysteine, hydroxyures and cycloherimide on maternal repair system operative in female Drosophila was studied using rod-X males and Oster females. The number of parental matings was kept constant. A new method of statistical analysis was employed to examine the frequency of sex-chromosome loss in these experiments. A re-analysis of published data was also done using this method. The existence of a maternal repair system was not upheld. The observed discrepancies between data reported herein and those published earlier and the possible reasons are discussed
On the robustness of bucket brigade quantum RAM
We study the robustness of the bucket brigade quantum random access memory
model introduced by Giovannetti, Lloyd, and Maccone [Phys. Rev. Lett. 100,
160501 (2008)]. Due to a result of Regev and Schiff [ICALP '08 pp. 773], we
show that for a class of error models the error rate per gate in the bucket
brigade quantum memory has to be of order (where is the
size of the memory) whenever the memory is used as an oracle for the quantum
searching problem. We conjecture that this is the case for any realistic error
model that will be encountered in practice, and that for algorithms with
super-polynomially many oracle queries the error rate must be
super-polynomially small, which further motivates the need for quantum error
correction. By contrast, for algorithms such as matrix inversion [Phys. Rev.
Lett. 103, 150502 (2009)] or quantum machine learning [Phys. Rev. Lett. 113,
130503 (2014)] that only require a polynomial number of queries, the error rate
only needs to be polynomially small and quantum error correction may not be
required. We introduce a circuit model for the quantum bucket brigade
architecture and argue that quantum error correction for the circuit causes the
quantum bucket brigade architecture to lose its primary advantage of a small
number of "active" gates, since all components have to be actively error
corrected.Comment: Replaced with the published version. 13 pages, 9 figure
Quantum query algorithms are completely bounded forms
We prove a characterization of quantum query algorithms in terms of polynomials satisfying a certain (completely bounded) norm constraint. Based on this, we obtain a refined notion of approximate polynomial degree that equals the quantum query complexity, answering a question of Aaronson et al. (CCC’16). Using this characterization, we show that many polynomials of degree at least 4 are far from those coming from quantum query algorithms. Our proof is based on a fundamental result of Christensen and Sinclair (J. Funct. Anal., 1987) that generalizes the well-known Stinespring representation for quantum channels to multilinear forms. We also give a simple and short proof of one of the results of Aaronson et al. showing an equivalence between one-query quantum algorithms and bounded quadratic polynomials
Genetic differentiation of growth parameters in Brassica species
Fourteen collections from the Brassica species, B.Juncea, B. nap us, B. carinata and B. campestris showed substantial variability for growth parameters including vegetative (VPD) and reproductive phase (RPD) duration. In general, seed yield in all maturity groups was associated with growth parameters, particularly, VPD, RPD and flowering phase duration, for example, high yielders in the early maturity group and 60-75 days of VPD and 38-40 days of RPD. In contrast, those in the late maturity group had more than 100 days of VPD and relatively short, but varying RPD of 25-50 days. In the medium maturity group, high yields were often found to be associated with relatively long RPD. The yields of B. napus and B. carinata could be improved by shortening total crop duration and increasing RPD. Selection for optimal vegetative phase durations in the progeny of inter-specific hybrids could further improve the yields In Brassica
Genetic variability for plant type traits in Brassica species
Four species of Brassica viz., Brassica juncea, B. napus, B. carinata and B. campestris were evaluated over two years for plant type traits including basal branching. In B. juncea there was greater variation for plant height but not for seed yield. It was only next to B. campestris followed by B. napus for variation in basal branching trait. While, in B. campestris there was no genetic variation for basal branching trait, but it showed greater variation for days to flowering, total number of primary and secondary branches
Quantum Query Algorithms are Completely Bounded Forms
We prove a characterization of t-query quantum algorithms in terms of the unit ball of a
space of degree-2t polynomials. Based on this, we obtain a refined notion of approximate polynomial
degree that equals the quantum query complexity, answering a question of Aaronson et
al. (CCC’16). Our proof is based on a fundamental result of Christensen and Sinclair (J. Funct.
Anal., 1987) that generalizes the well-known Stinespring representation for quantum channels
to multilinear forms. Using our characterization, we show that many polynomials of degree
four are far from those coming from two-query quantum algorithms. We also give a simple and
short proof of one of the results of Aaronson et al. showing an equivalence between one-query
quantum algorithms and bounded quadratic polynomials
Genomic analysis of Xenopus organizer function
BACKGROUND: Studies of the Xenopus organizer have laid the foundation for our understanding of the conserved signaling pathways that pattern vertebrate embryos during gastrulation. The two primary activities of the organizer, BMP and Wnt inhibition, can regulate a spectrum of genes that pattern essentially all aspects of the embryo during gastrulation. As our knowledge of organizer signaling grows, it is imperative that we begin knitting together our gene-level knowledge into genome-level signaling models. The goal of this paper was to identify complete lists of genes regulated by different aspects of organizer signaling, thereby providing a deeper understanding of the genomic mechanisms that underlie these complex and fundamental signaling events. RESULTS: To this end, we ectopically overexpress Noggin and Dkk-1, inhibitors of the BMP and Wnt pathways, respectively, within ventral tissues. After isolating embryonic ventral halves at early and late gastrulation, we analyze the transcriptional response to these molecules within the generated ectopic organizers using oligonucleotide microarrays. An efficient statistical analysis scheme, combined with a new Gene Ontology biological process annotation of the Xenopus genome, allows reliable and faithful clustering of molecules based upon their roles during gastrulation. From this data, we identify new organizer-related expression patterns for 19 genes. Moreover, our data sub-divides organizer genes into separate head and trunk organizing groups, which each show distinct responses to Noggin and Dkk-1 activity during gastrulation. CONCLUSION: Our data provides a genomic view of the cohorts of genes that respond to Noggin and Dkk-1 activity, allowing us to separate the role of each in organizer function. These patterns demonstrate a model where BMP inhibition plays a largely inductive role during early developmental stages, thereby initiating the suites of genes needed to pattern dorsal tissues. Meanwhile, Wnt inhibition acts later during gastrulation, and is essential for maintenance of organizer gene expression throughout gastrulation, a role which may depend on its ability to block the expression of a host of ventral, posterior, and lateral fate-specifying factors
Genetic potential of artificially synthesized Brassica juncea for yield improvement
A study was made to compare the potential of artificially synthesized Brassica juncea strains in inter-varietal crosses for basal branching characters and seed yield. Sixty four F3 families of synthetic x synthetic, synthetic x cultivar, and cultivar x cultivar crosses were studied and from among them thirty two superior F3 families were selected and advanced to F4 generation. Artifically synthesized materials generate more useful variability than those by usual inter-varietal crosses
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