Efficiency of different culture mediums and explant types of some Citrus rootstocks on somatic embryogenesis : [21]

Callus induction, somatic embryogenesis and plant regeneration were obtained in ten different Citrus genotypes [Citrus aurantium L. (cv 'Tuzcu 891 '), Citrus aurantium L. (cv 'Tuzcu 31-31'), Citrus aurantium L. (cv 'Gou Tou'), Citrus sinensis (L.) Osb. (cv 'Alanya Dilimli'), Citrus reshni Hort. ex.Tan. (cv 'Cyprus Cleopatra mandarine'), Poncirus trifoliata (L) Raf (cv 'Pomeroy'), Citrus sinensis (L) Osb. x Poncirus trifoliata (L) Raf. (cv 'Tuzcu M2 Citrange'), Citrus sinensis (L) Osb. x Poncirus trifoliata (L) Raf. (cv 'Carrizo Citrange'), Citrus paradisi Macf. x Poncirus trifoliata (L) Raf. (cv 'Swingle Citrumelo'), Citrus volkameriana Tan.& Pasg. (cv 'CRC 01 Volkameriana') from style and ovule explants. Explants were cultured on different culture media. The nutrients of Murashige and Skoog medium (MS) and Murashige and Tucker (MT) vitamins supplemented with 500 mg/l Malt Extract (ME), with 1 mg/l 2, 4-D and three different concentration of BA (0, 0.5, 1 mg/l) were used for first year experiments. MS basal medium was used alone with ME and three different concentration of BA (1, 2, 3 mg/l) for style explants for the second year experiment. MS nutrients and MT vitamins with ME were used alone and 2, 4-D (1 mg/l) and BA (0, 0.5, 1 mg/l) used for ovule culture experiment for the second year experiments. Sucrose was used as a carbon source (50 g/l) for all experirnents. The different genotypes showed different embryogenic frequency from style and ovule experiments. Percentages of style explants producing somatic embryos ranged from 0% (AREC Swingle Citrumelo, M2 Citrange, Volkameriana, Pomeroy trifoliate) to 100% (Gou Tou Sour Orange). Percentages of ovule explants producing somatic embryos ranged from 0% (Carrizo Citrange, Alanya Dilimli Sweet Orange, AREC Swingle Citrumelo) to 100% (Tuzcu 891 and Cleopatra Mandarine). About 4 weeks later somatic embryos developed into plantlets. Genetic stability of callus lines was determined by SSR markers. (Texte intégral

Genetic characterization of citrus rootstocks by using STMS markers : [P24]

STMS markers were used to characterize 41 Citrus rootstocks: A total of 10 Citrus-specific primers were tested, and 9 produced clear, reproducible and discrete bands. Primer Ci03C08 did not give clear amplification and reproducible fragments with all genotypes. The number of fragments amplified from individual Citrus genotypes with each primer pair ranged from one to three. Three fragments per primer pair would be the number expected from triploid Tuzcu M02 Citrange. Primer pair MEST458 from EST library was produced eleven different size fragments (between 203 bp-230 bp). The primer pair MESTl21 and MEST431 from EST library were produced eight (172 bp-202 bp) and six different fragments (322 bp-342 bp) respectively. Primer pair CI02D04B from genomic library was the most informative and polymorphic that produced sixteen fragments with the genotypes studied ranged from 188 bp to 250 bp. Primer pair Ci03G05 and Ci03D12a were produced twelve bands and primer CI02D09 was given thirteen bands. Primer Ci02GI2 and C102A09 from genomic library produced ten and nine bands respectively. Genetic similarity values (Nei and Li, 1979) were calculated and UPGMA (Unweighted pair-group method analysis) cluster analysis was performed to generate a dendogram. The obtained results confirmed the utility of SSR markers to discriminate among Citrus genotypes and to determine the genetic diversity among cultivars. This information is useful for germplasm characterization and identification of cultivars. (Texte intégral

Non-relativistic Lee Model on two Dimensional Riemannian Manifolds

This work is a continuation of our previous work (JMP, Vol. 48, 12, pp. 122103-1-122103-20, 2007), where we constructed the non-relativistic Lee model in three dimensional Riemannian manifolds. Here we renormalize the two dimensional version by using the same methods and the results are shortly given since the calculations are basically the same as in the three dimensional model. We also show that the ground state energy is bounded from below due to the upper bound of the heat kernel for compact and Cartan-Hadamard manifolds. In contrast to the construction of the model and the proof of the lower bound of the ground state energy, the mean field approximation to the two dimensional model is not similar to the one in three dimensions and it requires a deeper analysis, which is the main result of this paper.Comment: 18 pages, no figure

Effects of chemical composition and B2 order on phonons in bcc Fe–Co alloys

The phonon density of states (DOS) gives insight into interatomic forces and provides the vibrational entropy, making it a key thermodynamic function for understanding alloy phase transformations. Nuclear resonant inelastic x-ray scattering and inelastic neutron scattering were used to measure the chemical dependence of the DOS of bcc Fe–Co alloys. For the equiatomic alloy, the A2→B2 (chemically disordered→chemically ordered) phase transformation caused measurable changes in the phonon spectrum. The measured change in vibrational entropy upon ordering was −0.02±0.02 k_B/atom, suggesting that vibrational entropy results in a reduction in the order–disorder transition temperature by 60±60 K. The Connolly–Williams cluster inversion method was used to obtain interaction DOS (IDOS) curves that show how point and pair variables altered the phonon DOS of disordered bcc Fe–Co alloys. These IDOS curves accurately captured the change in the phonon DOS and vibrational entropy of the B2 ordering transition

Supergrassmannian and large N limit of quantum field theory with bosons and fermions

We study a large N_{c} limit of a two-dimensional Yang-Mills theory coupled to bosons and fermions in the fundamental representation. Extending an approach due to Rajeev we show that the limiting theory can be described as a classical Hamiltonian system whose phase space is an infinite-dimensional supergrassmannian. The linear approximation to the equations of motion and the constraint yields the 't Hooft equations for the mesonic spectrum. Two other approximation schemes to the exact equations are discussed.Comment: 24 pages, Latex; v.3 appendix added, typos corrected, to appear in JM

Does a computer have an arrow of time?

In [Sch05a], it is argued that Boltzmann's intuition, that the psychological arrow of time is necessarily aligned with the thermodynamic arrow, is correct. Schulman gives an explicit physical mechanism for this connection, based on the brain being representable as a computer, together with certain thermodynamic properties of computational processes. [Haw94] presents similar, if briefer, arguments. The purpose of this paper is to critically examine the support for the link between thermodynamics and an arrow of time for computers. The principal arguments put forward by Schulman and Hawking will be shown to fail. It will be shown that any computational process that can take place in an entropy increasing universe, can equally take place in an entropy decreasing universe. This conclusion does not automatically imply a psychological arrow can run counter to the thermodynamic arrow. Some alternative possible explanations for the alignment of the two arrows will be briefly discussed

Point Interaction in two and three dimensional Riemannian Manifolds

We present a non-perturbative renormalization of the bound state problem of n bosons interacting with finitely many Dirac delta interactions on two and three dimensional Riemannian manifolds using the heat kernel. We formulate the problem in terms of a new operator called the principal or characteristic operator. In order to investigate the problem in more detail, we then restrict the problem to one particle sector. The lower bound of the ground state energy is found for general class of manifolds, e.g., for compact and Cartan-Hadamard manifolds. The estimate of the bound state energies in the tunneling regime is calculated by perturbation theory. Non-degeneracy and uniqueness of the ground state is proven by Perron-Frobenius theorem. Moreover, the pointwise bounds on the wave function is given and all these results are consistent with the one given in standard quantum mechanics. Renormalization procedure does not lead to any radical change in these cases. Finally, renormalization group equations are derived and the beta-function is exactly calculated. This work is a natural continuation of our previous work based on a novel approach to the renormalization of point interactions, developed by S. G. Rajeev.Comment: 43 page

A Many-body Problem with Point Interactions on Two Dimensional Manifolds

A non-perturbative renormalization of a many-body problem, where non-relativistic bosons living on a two dimensional Riemannian manifold interact with each other via the two-body Dirac delta potential, is given by the help of the heat kernel defined on the manifold. After this renormalization procedure, the resolvent becomes a well-defined operator expressed in terms of an operator (called principal operator) which includes all the information about the spectrum. Then, the ground state energy is found in the mean field approximation and we prove that it grows exponentially with the number of bosons. The renormalization group equation (or Callan-Symanzik equation) for the principal operator of the model is derived and the $\beta$ function is exactly calculated for the general case, which includes all particle numbers.Comment: 28 pages; typos are corrected, three figures are adde

Subsumption architecture for enabling strategic coordination of robot swarms in a gaming scenario

The field of swarm robotics breaks away from traditional research by maximizing the performance of a group - swarm - of limited robots instead of optimizing the intelligence of a single robot. Similar to current-generation strategy video games, the player controls groups of units - squads - instead of the individual participants. These individuals are rather unintelligent robots, capable of little more than navigating and using their weapons. However, clever control of the squads of autonomous robots by the game players can make for intense, strategic matches. The gaming framework presented in this article provides players with strategic coordination of robot squads. The developed swarm intelligence techniques break up complex squad commands into several commands for each robot using robot formations and path finding while avoiding obstacles. These algorithms are validated through a 'Capture the Flag' gaming scenario where a complex squad command is split up into several robot commands in a matter of milliseconds

Chemotherapeutic drug-specific alteration of microvascular blood flow in murine breast cancer as measured by diffuse correlation spectroscopy

The non-invasive, in vivo measurement of microvascular blood flow has the potential to enhance breast cancer therapy monitoring. Here, longitudinal blood flow of 4T1 murine breast cancer (N=125) under chemotherapy was quantified with diffuse correlation spectroscopy based on layer models. Six different treatment regimens involving doxorubicin, cyclophosphamide, and paclitaxel at clinically relevant doses were investigated. Treatments with cyclophosphamide increased blood flow as early as 3 days after administration, whereas paclitaxel induced a transient blood flow decrease at 1 day after administration. Early blood flow changes correlated strongly with the treatmePeer ReviewedPostprint (published version