PA Model Research Articles

Palliative treatment of unresectable pancreatico-biliary cancer by either Gemcitabine or Octreotide/Imatinib – impact on biomarkers of angiogenesis

15101 Background: Gemcitabine represents standard Tx for unresectable cancers of the pancreas / distal biliary tract. Recent interest has focused on antiangiogenic properties in a mouse model of pa...

REBUTTAL FROM DR. ROBERTSON

REBUTTAL FROM DR. ROBERTSON

Nonstandard models that are definable in models of Peano Arithmetic

AbstractIn this paper, we investigate definable models of Peano Arithmetic PA in a model of PA. For any definable model N without parameters in a model M, we show that N is isomorphic to M if M is elementary extension of the standard model and N is elementarily equivalent to M. On the other hand, we show that there is a model M and a definable model N with parameters in M such that N is elementarily equivalent to M but N is not isomorphic to M. We also show that there is a model M and a definable model N with parameters in M such that N is elementarily equivalent to M, and N is isomorphic to M, but N is not definably isomorphic to M. And also, we give a generalization of Tennenbaum's theorem. At the end, we give a new method to construct a definable model by a refinement of Kotlarski's method. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Strong initial segments of models of IΔ0

McAloon showed that if ${\cal A}$ is a nonstandard model of $I\Delta_0$, then some initial segment of ${\cal A}$ is a nonstandard model of PA. Sommer and D'Aquino characterized, in terms of the Wainer functions, the elements that can belong to such an ini

Physician Assistant Education: An Abbreviated History

Physician assistant educational programs began as part of a larger movement in the creation of new health professions. The educational organizations of the PA profession were fashioned by physician leaders in medical education. In developing PA programs, progressive physicians and others created innovative approaches to medical education that included decentralized education, emphasis on psychosocial components, and creative deployment approaches. The competency-based PA model employed ideas and elements that were ahead of their time in health professions education. PA education moved to a degree-based system in the 1990s. PA education was based on nontraditional models of medical education that have proved to be successful in training effective generalist clinicians.

Behavioral modeling of power amplifiers for wireless applications

In this paper, an improved empirical behavioral model for radio-frequency power amplifiers (RF-PAs) is presented. The model was implemented in a commercial nonlinear microwave simulator. It belongs to the category of bandpass PA models, which exhibits memory effects due to the low frequency dependence of bias and temperature. Additionally, it facilitates accurate and efficient system level simulations of RF-PA large-signal behaviors such as self-bias, AM-AM, AM-PM, gain expansion effects, and intermodulation distortion (IMD) sweet-spots. The model was validated using measurement data obtained from a commercial CDMA PA at 1.88 GHz. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.

The Effect that the Visual and Haptic Problems Associated with Touching a Projection Augmented Model Have on Object-Presence

A projection augmented model (PA model) is a type of haptic augmented reality display. It consists of a real physical model, onto which a computer image is projected to create a realistic looking object. Thus, a PA model creates the illusion of actually being the object that it represents, as opposed to a white model and a projected image. Users can physically touch the surface of a PA model with their bare hands, which has experiential value for the types of applications for which they are being developed. However, the majority of PA models do not provide haptic feedback for material properties such as texture, and hence feel incorrect when they are touched. In addition, most PA models are front-projected which means the projected image appears on the back of the user's hand, and their hand casts a shadow on the display. Previous research has found that touching this type of PA model reduces a user's sense of object presence. The empirical study reported in this paper investigated which of the problems had a greater effect on object presence. It was found that object presence was significantly higher when correct haptic feedback for material properties was provided; however eliminating the visual projection problems rarely affected object presence. These results have implications for the direction in which PA model technology should be developed. They also have implications for theory on how the haptic and visual senses contribute to a person's sense of object presence, and indeed presence.

Automorphisms of models of arithmetic: A unified view

We develop the method of iterated ultrapower representation to provide a unified and perspicuous approach for building automorphisms of countable recursively saturated models of Peano arithmetic PA . In particular, we use this method to prove Theorem A below, which confirms a long-standing conjecture of James Schmerl. Theorem A If M is a countable recursively saturated model of PA in which N is a strong cut, then for any M 0 ≺ M there is an automorphism j of M such that the fixed point set of j is isomorphic to M 0 . We also fine-tune a number of classical results. One of our typical results in this direction is Theorem B below, which generalizes a theorem of Kaye–Kossak–Kotlarski (in what follows Aut ( X ) is the automorphism group of the structure X , and Q is the ordered set of rationals). Theorem B Suppose M is a countable recursively saturated model of PA in which N is a strong cut. There is a group embedding j ↦ j ˆ from Aut ( Q ) into Aut ( M ) such that for each j ∈ Aut ( Q ) that is fixed point free, j ˆ moves every undefinable element of M .

Numbers and Polynomials- 50 years since the publication of Wittgenstein's Bemerkungen über die Grundlagen der Mathematik (1956): Mathematical and Educational reflections

According to L. Wittgenstein, the meaning of a mathematical object is to be grounded upon its use. In this paper we consider Robinson theory Q, the subtheory of firstorder Peano Arithmetic PA; some theorems and conjectures can be interpreted over one model of Q given by a universe of polynomials; with respect to nonconstant polynomials some proofs by elementary methods are given and compared with corresponding results in the standard model of PA. We conclude that the creative power of the language can be pointed out in how the language itself is embedded into the rest of human activities, and this is an important track to follow for researchers in mathematics education.

Antibodies raised against N'-terminal Pseudomonas aeruginosa flagellin prevent mortality in lethal murine models of infection

The goal of this study was to investigate if antibodies raised against N'-terminal Pseudomonas aeruginosa (Pa) flagellin could afford protection in two lethal mouse models of Pa infection. To that end, rabbit polyclonal antibodies were generated against the N'-terminal domains (amino acids 1-156) of recombinant Pa01 or Salmonella muenchen flagellins, termed anti-N'-fla-b and anti-N'-fla-Sm, respectively. In vitro, anti-N'-fla-b but not anti-N'-fla-Sm IgG specifically recognized recombinant and Pa endogenous flagellin type b proteins, total bacterial lysates of Pa type b, and inhibited Pa01 invasion into A549 cells. In vivo, administration of anti-N'-fla-b afforded a remarkable improvement in survival in lethal peritonitis (90% vs. 12% in control; p<0.001) and burn infection (83% vs. 8-17% in control groups; p<0.005) Pa models. These findings would suggest that the N'-terminal domain of Pa flagellin harbors critically important bioactive domains and that an antibody-targeted, neutralization approach directed at this region could provide a novel therapeutic strategy to combat Pa infection.

Jet production in pA and AA collisions in the perturbative QCD pomeron model

Inclusive cross-sections for gluon jet production are studied numerically in the perturbative QCD pomeron model for pA and central AA collisions at high energies. Two forms for the inclusive cross-sections, with and without emission from the triple pomeron vertex, are compared. The difference was found to reduce to a numerical factor 0.7-0.8 for momenta below the saturation momentum Q_s. Above Q_s no difference was found at all. For pA collisions the jet spectrum was found to be \sim A^{0.7} at momenta below Q_s and \sim A^{0.9} above it. For central AA collisions it was found to be \sim A below Q_s and \sim A^{1.1} above it. At large momenta k the spectrum goes like 1/k^{2.7 - 3.3} flattenung with energy.

Does Touching a Projection Augmented Model and Interacting with it using a Spatially-Coincident Device, Affect a User's Perception of its Size?

A Projection Augmented model (PA model) is a novel type of display. It consists of a real physical model, onto which a computer image is projected to create a realistic looking object. PA models provide their users with whole-hand haptic feedback and support spatially-coincident haptic interaction devices. This paper reports on an experiment that investigated the effect these factors have on a user’s perception of the size a PA model. Results showed that touching a PA model increased the accuracy of size estimates; however using a spatially-coincident haptic interaction device had no effect.

The Cronin effect, quantum evolution and the color glass condensate

We show that the numerical solution of the classical SU(3) Yang–Mills equations of motion in the McLerran–Venugopalan model for gluon production in central heavy ion collisions leads to a suppression at low pt and an enhancement at the intermediate pt region as compared to peripheral heavy ion and pp collisions at the same energy. Our results are compared to previous, color glass condensate inspired calculations of gluon production in heavy ion collisions. We revisit the predictions of the color glass condensate model for pA (dA) collisions in leading order and show that quantum evolution—in particular, the phenomenon of geometric scaling and change of anomalous dimensions—preserves the Cronin enhancement of pA cross section (when normalized to the leading twist term) in the leading order approximation even though the pt spectrum can change. We comment on the case when gluon radiation is included.

Strongly maximal subgroups determined by elements in interstices

AbstractContinuing the earlier research in [1] and [4] we work out a class of interstices in countable arithmetically saturated models of PA in which selective types are realized and a class of interstices in which 2‐indiscernible types are realized (and hence, there exist elements whose stabilizers are strongly maximal)

Some highly saturated models of Peano arithmetic

Some highly saturated models of Peano Arithmetic are constructed in this paper, which consists of two independent sections. In § 1 we answer a question raised in [10] by constructing some highly saturated, rather classless models of PA. A question raised in [7], [3], ]4] is answered in §2, where highly saturated, nonstandard universes having no bad cuts are constructed.Highly saturated, rather classless models of Peano Arithmetic were constructed in [10]. The main result proved there is the following theorem. If λ is a regular cardinal and is a λ-saturated model of PA such that ∣M∣ &gt; λ, then has an elementary extension of the same cardinality which is also λ-saturated and which, in addition, is rather classless. The construction in [10] produced a model for which cf() = λ+. We asked in Question 5.1 of [10] what other cofinalities could such a model have. This question is answered here in Theorem 1.1 of §1 by showing that any cofinality not immediately excluded is possible. Its proof does not depend on the theorem from [10]; in fact, the proof presented here gives a proof of that theorem which is much simpler and shorter than the one in [10].Recursively saturated, rather classless κ-like models of PA were constructed in [9]. In the case of singular κ such models were constructed whenever cf(κ) &gt; ℵ0; no additional set-theoretic hypothesis was needed.

Automorphism groups of models of Peano arithmetic

Which groups are isomorphic to automorphism groups of models of Peano Arithmetic? It will be shown here that any group that has half a chance of being isomorphic to the automorphism group of some model of Peano Arithmetic actually is.For any structure , let Aut() be its automorphism group. There are groups which are not isomorphic to any model = (N, +, ·, 0, 1, ≤) of PA. For example, it is clear that Aut(N), being a subgroup of Aut((, &lt;)), must be torsion-free. However, as will be proved in this paper, if (A, &lt;) is a linearly ordered set and G is a subgroup of Aut((A, &lt;)), then there are models of PA such that Aut() ≅ G.If is a structure, then its automorphism group can be considered as a topological group by letting the stabilizers of finite subsets of A be the basic open subgroups. If ′ is an expansion of , then Aut(′) is a closed subgroup of Aut(). Conversely, for any closed subgroup G ≤ Aut() there is an expansion ′ of such that Aut(′) = G. Thus, if is a model of PA, then Aut() is not only a subgroup of Aut((N, &lt;)), but it is even a closed subgroup of Aut((N, ′)).There is a characterization, due to Cohn [2] and to Conrad [3], of those groups G which are isomorphic to closed subgroups of automorphism groups of linearly ordered sets.

Minimality and completions of PA

The results in this paper say that natural upper bounds for sets of degrees associated with theories and models of arithmetic cannot be minimal. The basic new result says that for any completion T of PA, there is another completion S such that S&lt;TT and Rep(S) = Rep(T). This immediately implies that deg(T) is not minimal over {deg(X): X ∈ Rep(T)}. As an application of the basic result, we obtain the fact that if is a non-standard model of TA (true arithmetic), then deg () cannot be minimal over {deg(X): X is arithmetical}. More generally, if is a non-standard model of an arbitrary completion T of PA, then deg() cannot be minimal over {deg(): X ∈ Rep(T)}. We vary the basic result, making S′ ≡TT′. As an application of the variant, we obtain the fact that if is a non-standard model of PA, then {deg(): ≅ } has no minimal element.The remainder of the present section gives a brief account of the background needed for the basic new result and the variant. These two results are proved in Section 2. The applications are given in Section 3, along with further background needed for the applications. One important source of ideas used in the present paper is a paper of Scott [9]. In addition, there are ideas taken from Tennenbaum [12], Feferman [3], Marker [6], [7], and Solovay. Chapter 19 of [1] gathers together most of this material. In fact, it contains all that is really essential. In one application, we appeal to Solovay's result on degrees of models of an arbitrary completion of PA, a result which is not completely proved in [1]. However, for the best application, which implies all the others, we use only some ideas from the proof of Solovay's theorem. These are given in lemmas that are proved in Section 3, where they are needed, or taken from [1], While the proof of Solovay's result requires an infinitely nested priority construction, our best application rests on nothing more than finite-injury constructions.

Computability in structures representing a Scott set

Continuing work begun in [10], we utilize a notion of forcing for which the generic objects are structures and which allows us to determine whether these “generic” structures compute certain sets and enumerations. The forcing conditions are bounded complexity types which are consistent with a given theory and are elements of a given Scott set. These generic structures will “represent” this given Scott set, in the sense that the structure has a certain weak saturation property with respect to bounded complexity types in the Scott set. For example, if ? is a nonstandard model of PA, then ? represents the Scott set ? = n∈ω | ?⊧“the nth prime divides a” | a∈?.

Emerging US public affairs practice: the 2000+ PA model

AbstractMany larger US corporations are re‐assessing their participation in the public policy process and their entire approach to managing public affairs. This paper will attempt to synthesise much of what is happening to US corporate public affairs. It describes the forces driving the changes and addresses the ways corporations are responding to these forces. Finally, the paper offers an argument of the ‘New Public Affairs’ 2000 and beyond model as it will likely be practised in the USA, and perhaps elsewhere, at least early into this decade. Copyright © 2001 Henry Stewart Publications

Molecular Dynamics Simulations of PNA·DNA and PNA·RNA Duplexes in Aqueous Solution

Molecular dynamics simulations have been used to study the structure and flexibility of a DNA·PNA duplex and a RNA·PNA duplex in aqueous solution. In this study, trajectories have been generated starting from three different conformations of the PNA·DNA and PNA·RNA duplexes: A-like, B-like, and PA/B-like. For the DNA·PNA duplex, the three trajectories converge within the nanosecond time scale to give structures resembling closely the PB model. The RNA·PNA duplex trajectories started from A- and PA-forms converge to give structures resembling the PA model, but the trajectory begun from the B-like conformation leads to an unfolded duplex. Despite the similarity between PA and PB structures calculations show the existence of important differences in terms of molecular recognition between both conformations. Analysis of the trajectories shows that the PNA backbone is very flexible provided that the backbone movements do not alter the positioning of the bases. It is found that PNA is able to distort the structure of RNA and especially DNA strands during the formation of the PNA·DNA and PNA·RNA hybrids. The impact of these findings in antigene and antisense therapies is discussed.