Stringy K-theory and the Chern character

For a finite group G acting on a smooth projective variety X, we construct two new G-equivariant rings: first the stringy K-theory of X, and second the stringy cohomology of X. For a smooth Deligne-Mumford stack Y we also construct a new ring called the full orbifold K-theory of Y. For a global quotient Y=[X/G], the ring of G-invariants of the stringy K-theory of X is a subalgebra of the full orbifold K-theory of the the stack Y and is linearly isomorphic to the ``orbifold K-theory'' of Adem-Ruan (and hence Atiyah-Segal), but carries a different, ``quantum,'' product, which respects the natural group grading. We prove there is a ring isomorphism, the stringy Chern character, from stringy K-theory to stringy cohomology, and a ring homomorphism from full orbifold K-theory to Chen-Ruan orbifold cohomology. These Chern characters satisfy Grothendieck-Riemann-Roch for etale maps. We prove that stringy cohomology is isomorphic to Fantechi and Goettsche's construction. Since our constructions do not use complex curves, stable maps, admissible covers, or moduli spaces, our results simplify the definitions of Fantechi-Goettsche's ring, of Chen-Ruan's orbifold cohomology, and of Abramovich-Graber-Vistoli's orbifold Chow. We conclude by showing that a K-theoretic version of Ruan's Hyper-Kaehler Resolution Conjecture holds for symmetric products. Our results hold both in the algebro-geometric category and in the topological category for equivariant almost complex manifolds.Comment: Exposition improved and additional details provided. To appear in Inventiones Mathematica

Microscopic theory for quantum mirages in quantum corrals

Scanning tunneling microscopy permits to image the Kondo resonance of a single magnetic atom adsorbed on a metallic surface. When the magnetic impurity is placed at the focus of an elliptical quantum corral, a Kondo resonance has been recently observed both on top of the impurity and on top of the focus where no magnetic impurity is present. This projection of the Kondo resonance to a remote point on the surface is referred to as quantum mirage. We present a quantum mechanical theory for the quantum mirage inside an ideal quantum corral and predict that the mirage will occur in corrals with shapes other than elliptical

Prebiotic effects of oligosaccharides extracted from palm kernel expeller on different levels of Salmonella typhimurium infection in chicks

Prebiotic effects of oligosaccharides extract from palm kernel expeller (OligoPKE) on Salmonella typhimurium were investigated in chicks in two experiments. Results of the first experiment showed that OligoPKE reduced the colonization of Salmonella typhimurium in the cecum and increased the immunoglobulin A (IgA) production in the blood and jejunum. The second experiment further investigated the prebiotic efficacy of dietary supplementation of OligoPKE on three levels of Salmonella typhimurium infection (1.0 x 104 Colony-forming unit (CFU)/mL; 1.0 x 106 CFU/mL and 1.0 x 108 CFU/mL) in chicks. OligoPKE reduced the colonization of Salmonella in the medium and high levels of infection. IgA level in serum and jejunum content increased significantly in all the three levels of infection when chicks received OligoPKE in their diet. Interleukin 8, and 10; interferon-α; and tumour necrosis factor genes were up-regulated in the jejunum of the infected chicks, and OligoPKE down-regulated these gene expressions. Results of the current study indicated that OligoPKE, an oligosaccharides extract from palm kernel expeller, is capable of reducing colonization of Salmonella typhimurium in young chicks, and boosted their immunity.Keywords: chicken, immunoglobulin, immune gene, microbial populatio

A Hybrid Monte Carlo Method for Surface Growth Simulations

We introduce an algorithm for treating growth on surfaces which combines important features of continuum methods (such as the level-set method) and Kinetic Monte Carlo (KMC) simulations. We treat the motion of adatoms in continuum theory, but attach them to islands one atom at a time. The technique is borrowed from the Dielectric Breakdown Model. Our method allows us to give a realistic account of fluctuations in island shape, which is lacking in deterministic continuum treatments and which is an important physical effect. Our method should be most important for problems close to equilibrium where KMC becomes impractically slow.Comment: 4 pages, 5 figure

Quasiparticle Scattering Interference in High Temperature Superconductors

We propose that the energy-dependent spatial modulation of the local density of states seen by Hoffman, et al [hoff2] is due to the scattering interference of quasiparticles. In this paper we present the general theoretical basis for such an interpretation and lay out the underlying assumptions. As an example, we perform exact T-matrix calculation for the scattering due to a single impurity. The results of this calculation is used to check the assumptions, and demonstrate that quasiparticle scattering interference can indeed produce patterns similar to those observed in Ref. [hoff2].Comment: RevTex4 twocolumn, 4 pages, 3 figures. Figs.2-3 virtually embedded (bacause of too big size) while jpg files available in the postscript/source package. Further polishe

Molecular Analysis of a Major Carpel Developmental Regulator: CRABS CLAW’s Protein Domains and Non-Cell-Autonomous Action

CRABS CLAW is a small protein belonging to the YABBY family, a plant specific protein family. In Arabidopsis thaliana it is expressed in the developing carpels and regulates the apical fusion of the two carpels, transmitting tract development, lateral growth, and nectary formation. The expression of CRC is rather complex with multiple expression domains throughout the young gynoecium and as for other YABBY proteins a non-cell-autonomous action has been described. However, only few regulators of CRC expression and target genes are described and the mode of non-cell-autonomous action is still unknown. This dissertation aims to identify transcriptional regulators, responsible for the proper temporal and spatial expression of CRC, the specification of CRC’s place in the adaxial-abaxial regulatory network and to clarify the means of its non-cell-autonomous action. The regulation of CRC expression has been analyzed via a large scale Yeast-1-Hybrid screen and identified over 100 potential regulators of CRC expression, integrating CRC tightly into the carpel developmental regulatory protein network. Further analysis of CRC function through expression analysis led to the identification of target genes of CRC like mir165/166, members of the KANADI gene family, and the HD ZIP III gene family. Both gene families are major players in the adaxial-abaxial regulatory network, involved in the development of all lateral plant organs such as leaves and floral organs. CRC supports KANADI action and activates the expression of other involved factors. In addition, CRC directly targets members of the HD ZIP III family. However, CRC’s position in the adaxial- abaxial regulatory network seems to be not conserved in other eudicots. CRC exhibits a non- cell-autonomous action which is conferred by at least two signaling pathways. Abaxial polarity is regulated by the activation of the mobile miRNA165/166. At the same time, localizations of GFP tagged CRC revealed the CRC protein to be mobile as it migrates into the adaxial domain in young gynoecia. In older gynoecia it was excluded from the adaxial domain. This study identified multiple unique features of CRC compared to its relatives. Its thightly controlled expression by over 100 putative regulators, integration in complex co-expression networks, adaxial and abaxial target genes, and its two mode non-cell-autonomous action indicate the important role in the complicated carpel development.CRABS CLAW ist ein kleines Protein der pflanzenspezifischen YABBY Protein Familie. In Arabidopsis thaliana ist es in den entwickelnden Fruchtblättern exprimiert und reguliert die apikale Fusion der Fruchtblätter, die Entwicklung des Transmissionskanal (einem Bereich des Septums), die Begrenzung des lateralen Wachstums des Gynoeceums, und die Bildung der Nektarien. Die Expression von CRC ist auf mehrere Bereiche im Fruchtblatt aufgeteilt und ebenso wurde ein nicht-zell-autonomer Effekt wie für andere YABBY Proteine beschrieben. Jedoch sind nur einige wenige Regulatoren der CRC Expression und Zielgene von CRC bekannt, sowie die Natur des mobilen Signals des nicht-zell-autonomen Effektes unbekannt ist. Daher zielt diese Dissertation darauf, zusätzliche transkriptionelle Regulatoren, die für die korrekte zeitliche und räumliche Expression von CRC nötig sind, zu identifizieren, sowie CRCs Position im adaxialen-abaxialen Netzwerk zu identifizieren und die Art und Weise des nicht-zell-autonomen Effektes zu klären. Die Expression von CRC wurde durch eine groß angelegte Hefe-1-Hybrid Analyse näher untersucht und über 100 mögliche Regulatoren der CRC Expression wurden identifiziert. Dies festigt CRCs Position im gen-regulatorischen Netzwerk der Fruchtblattentwicklung. Eine weitere Analyse der CRC Funktionen mittels Expressionsanalyse führte zu der Identifikation mehrerer Zielgene wie mir165/166, Mitglieder der KANADI Genfamilie und Mitglieder der HD ZIP III Genfamilie. Beide Genfamilien sind Hauptkomponenten des adaxial–abaxialen Regulationsnetzwerkes. Dabei unterstützt CRC die Funktion der KAN Proteine und reguliert die Expression anderer involvierter Gene. Zusätzlich reguliert CRC direkt die Expression einiger HD ZIP III Gene. Wobei die Regulation der adaxial-abaxialen Regulatoren durch CRC zwischen verschiedenen Eudikotylen nicht komplett konserviert ist. CRC weist eine nicht-zell-autonome Funktion auf, die durch mindestens zwei Signalübertragungswege vermittelt wird. Zum einen reguliert CRC die abaxiale Polarität durch die Aktivierung der mobilen miRNA165/166 und zum anderen durch direkten Transport des CRC Proteins. Lokalisierungen von mit GFP markierten CRC zeigten, dass das CRC Protein in den frühen Stadien des Gyneoceums von der abaxialen Domäne in die adaxiale wandert. In späteren Stadien ist CRC auf die abaxiale Domäne begrenzt. Diese Studie konnte mehrere einzigartige CRC Charakteristika identifizieren, die CRC von den anderen Mitgliedern der YABBY Familie unterscheidet. Seine stark kontrollierte Expression durch mehr als 100 mögliche Regulatoren, die Integration in ein kompliziertes Co- Expressions Netzwerk, adaxiale und abaxiale Zielgene, und mindestens zwei Möglichkeiten zur nicht-zell-autonomen Regulation, zeigen eindringlich die wichtige Rolle CRCs in der komplexen Karpellentwicklung auf

Conformal Affine Toda Soliton and Moduli of IIB Superstring on AdS5×S5AdS_5\times S^5

In this paper we interpret the hidden symmetry of the moduli space of IIB superstring on $AdS_{5}\times S^{5}$ in terms of the chiral embedding in $AdS_{5}$, which turns to be the $\mathbb{CP}^{3}$ conformal affine Toda model. We review how the position $\mu$ of poles in the Riemann-Hilbert formulation of dressing transformation and how the value of loop parameters $\mu$ in the vertex operator of affine algebra determines the moduli space of the soliton solutions, which describes the moduli space of the Green-Schwarz superstring. We show also how this affine SU(4) symmetry affinize the conformal symmetry in the twistor space, and how a soliton string corresponds to a Robinson congruence with twist and dilation spin coefficients $\mu$ of twistor.Comment: Final version, Misprints corrected, Note adde

On the speed of convergence to stationarity of the Erlang loss system

We consider the Erlang loss system, characterized by $N$ servers, Poisson arrivals and exponential service times, and allow the arrival rate to be a function of $N.$ We discuss representations and bounds for the rate of convergence to stationarity of the number of customers in the system, and display some bounds for the total variation distance between the time-dependent and stationary distributions. We also pay attention to time-dependent rates

Evidence building and information accumulation: Using the bayesian paradigm to advance child welfare intervention research

Objective: Intervention evaluation typically follows a frequentist paradigm: New analyses are conducted for each subsequent study, and findings are then used to improve policy practice. This approach largely ignores data from prior studies, leading to information loss and incomplete or inaccurate conclusions. Unlike the frequentist paradigm, the Bayesian paradigm uses formative data (as pri-ors), which can be updated with the summative data, thus building on existing evidence about an intervention’s effectiveness. Method: This article uses data from the Safe Families for Children randomized controlled trial to illustrate how the Bayesian paradigm incorporates prior evidence at the formative phase with data at the summative phase to provide a more comprehensive analysis. This approach is consistent with the scientific principle of evidence building. We compare the merits of each paradigm on two evaluation criteria: (a) p-values from a chi-square test, and (b) the probability that the intervention is superior to the comparison group on three outcome variables (protective custody, deflection from foster care, and whether repeat victimization occurred). Results: The Bayesian paradigm consistently outperformed the frequentist paradigm. Conclusion: The Bayesian paradigm is superior to the frequentist paradigm in demonstrating the effectiveness of an intervention, as evidenced by smaller p-values and a higher probability that the intervention group outperformed the comparison group

Quark zero modes in intersecting center vortex gauge fields

The zero modes of the Dirac operator in the background of center vortex gauge field configurations in $\R^2$ and $\R^4$ are examined. If the net flux in D=2 is larger than 1 we obtain normalizable zero modes which are mainly localized at the vortices. In D=4 quasi-normalizable zero modes exist for intersecting flat vortex sheets with the Pontryagin index equal to 2. These zero modes are mainly localized at the vortex intersection points, which carry a topological charge of $\pm 1/2$. To circumvent the problem of normalizability the space-time manifold is chosen to be the (compact) torus \T^2 and \T^4, respectively. According to the index theorem there are normalizable zero modes on \T^2 if the net flux is non-zero. These zero modes are localized at the vortices. On \T^4 zero modes exist for a non-vanishing Pontryagin index. As in $\R^4$ these zero modes are localized at the vortex intersection points.Comment: 20 pages, 4 figures, LaTeX2e, references added, treatment of ideal vortices on the torus shortene