197 research outputs found
Finitely generated almost universal varieties of -lattices
summary:A concrete category is (algebraically) {\it universal\/} if any category of algebras has a full embedding into , and is {\it almost universal\/} if there is a class \Cal C of -objects such that all non-constant homomorphisms between them form a universal category. The main result of this paper fully characterizes the finitely generated varieties of -lattices which are almost universal
Unpacking High-Impact Instructional Practices and Student Engagement in a Teacher Preparation Program
The literature on SoTL contains numerous studies examining the relationship between High-Impact Practices (HIPs) as adopted by the American Association of Colleges and Universities (AAC&U), student engagement, and student learning outcomes as measured on the National Survey of Student Engagement (NSSE). To further understand how these practices might affect student engagement and learning within college courses, this study examined the relationship between HIPs, reported student engagement and reported learning outcomes in a teacher preservice program. Focus group interviews and a modified version of the NSSE survey were used to “unpack” how these practices related to student engagement and learning in five courses with 94 enrolled students. Major themes from the analyses included the importance of applied learning, collaborative assignments, understanding diverse points of view and constructive feedback on assignments as essential components of engagement and learning. Implications for teaching and future research are discussed
Algebraic functor slices
AbstractForgetful functors of any two categories of monadic algebras over Letfor which the functor T in a monad T = (T, η, μ) is not naturally equivalent to the identity or a constant functor or to their coproduct are slice equivalent to one another. In particular, any two forgetful functors of nondegenerate varieties of algebras (that is, varieties which possess a term which is neither a projection nor a constant) are slice equivalent
An almost full embedding of the category of graphs into the category of abelian groups
We construct an embedding G of the category of graphs into the category of
abelian groups such that for graphs X and Y we have Hom(GX,GY)=Z[Hom(X,Y)], the
free abelian group whose basis is the set Hom(X,Y). The isomorphism is
functorial in X and Y. The existence of such an embedding implies that,
contrary to a common belief, the category of abelian groups is as complex and
comprehensive as any other concrete category. We use this embedding to settle
an old problem of Isbell whether every full subcategory of the category of
abelian groups, which is closed under limits, is reflective. A positive answer
turns out to be equivalent to weak Vopenka's principle, a large cardinal axiom
which is not provable but believed to be consistent with standard set theory.
Several known constructions in the category of abelian groups are obtained as
quick applications of the embedding. In the revised version we add some
consequences to the Hovey-Palmieri-Stricland problem about existence of
arbitrary localizations in a stable homotopy categoryComment: 20 page
On the spectrum of the Sinh-Gordon model in finite volume
We derive a characterization of the spectrum of the Sinh-Gordon model in
terms of certain nonlinear integral equations. There exists a large class of
solutions to these equations which allows a continuation between the infrared
and the ultraviolet limits, respectively. We present nontrivial evidence for
the claim that the class of solutions in question describes the spectrum of the
Sinh-Gordon model completely in both of these limits. The evidence includes
some nontrivial relations to Liouville theory.Comment: 33 pages, the new version corrects a mistake in the lattice TBA of
the previous version
TGFβ1 Overexpression by Keratinocytes Alters Skin Dendritic Cell Homeostasis and Enhances Contact Hypersensitivity
Overexpression of transforming growth factor beta-1 (TGFβ1) in mouse epidermis causes cutaneous inflammation and keratinocyte hyperproliferation. Here we examined acute effects of TGFβ1 overproduction by keratinocytes on skin dendritic cells (DCs). TGFβ1 induction for 2 and 4 days increased the numbers and CD86 expression of B220+ plasmacytoid DCs (pDCs) and CD207+CD103+, CD207−CD103−CD11b+, and CD207−CD103−CD11b− dermal DCs (dDCs) in skin-draining lymph nodes (SDLNs). The dermis of TGFβ1-overexpressing mice had significantly more pDCs, CD207+CD103+ dDCs, and CD207−CD11b+ dDCs in the absence of increased dermal proliferation. Application of dye, tetramethyl rhodamine iso-thiocyanate (TRITC), in dibutylpthalate (DBP) solution after TGFβ1 induction increased the numbers of TRITC+CD207− dDCs in SDLNs, and augmented TRITC/DBP-induced Langerhans cell (LC) migration 72hours post TRITC treatment. Consistent with this, LC migration was increased in vitro by TGFβ1 overexpression in skin explants and by exogenous TGFβ1 in culture media. Transient TGFβ1 induction during DNFB sensitization increased contact hypersensitivity responses by 1.5-fold. Thus, elevated epidermal TGFβ1 alone is sufficient to alter homeostasis of multiple cutaneous DC subsets, and enhance DC migration and immune responses to contact sensitizers. These results highlight a role for keratinocyte-derived TGFβ1 in DC trafficking and in the initiation of skin inflammation
Form factors in the Bullough-Dodd related models: The Ising model in a magnetic field
We consider particular modification of the free-field representation of the
form factors in the Bullough-Dodd model. The two-particles minimal form factors
are excluded from the construction. As a consequence, we obtain convenient
representation for the multi-particle form factors, establish recurrence
relations between them and study their properties. The proposed construction is
used to obtain the free-field representation of the lightest particles form
factors in the perturbed minimal models. As a significant example
we consider the Ising model in a magnetic field. We check that the results
obtained in the framework of the proposed free-field representation are in
agreement with the corresponding results obtained by solving the bootstrap
equations.Comment: 20 pages; v2: some misprints, textual inaccuracies and references
corrected; some references and remarks adde
Determining matrix elements and resonance widths from finite volume: the dangerous mu-terms
The standard numerical approach to determining matrix elements of local
operators and width of resonances uses the finite volume dependence of energy
levels and matrix elements. Finite size corrections that decay exponentially in
the volume are usually neglected or taken into account using perturbation
expansion in effective field theory. Using two-dimensional sine-Gordon field
theory as "toy model" it is shown that some exponential finite size effects
could be much larger than previously thought, potentially spoiling the
determination of matrix elements in frameworks such as lattice QCD. The
particular class of finite size corrections considered here are mu-terms
arising from bound state poles in the scattering amplitudes. In sine-Gordon
model, these can be explicitly evaluated and shown to explain the observed
discrepancies to high precision. It is argued that the effects observed are not
special to the two-dimensional setting, but rather depend on general field
theoretic features that are common with models relevant for particle physics.
It is important to understand these finite size corrections as they present a
potentially dangerous source of systematic errors for the determination of
matrix elements and resonance widths.Comment: 26 pages, 13 eps figures, LaTeX2e fil
Towards the Construction of Wightman Functions of Integrable Quantum Field Theories
The purpose of the ``bootstrap program'' for integrable quantum field
theories in 1+1 dimensions is to construct a model in terms of its Wightman
functions explicitly. In this article, this program is mainly illustrated in
terms of the sine-Gordon and the sinh-Gordon model and (as an exercise) the
scaling Ising model. We review some previous results on sine-Gordon breather
form factors and quantum operator equations. The problem to sum over
intermediate states is attacked in the short distance limit of the two point
Wightman function for the sinh-Gordon and the scaling Ising model.Comment: LATEX 18 pages, Talk presented at the '6th International Workshop on
Conformal Field Theories and Integrable Models', in Chernologka, September
200
- …