Promoting Public Health In The Context Of The “Obesity Epidemic”: False Starts And Promising New Directions

In the battle to combat obesity rates in the United States, several misconceptions have dominated policy initiatives. We address those misconceptions, including the notion that restrictive diets lead to long-term weight loss, that stigmatizing obesity is an effective strategy for promoting weight reduction, and that weight and physical health should be considered synonymous with one another. In offering correctives to each of these points, we draw on psychological science to suggest new policies that could be enacted at both the local and national levels. Instead of policies that rely solely on individual willpower, which is susceptible to failure, we recommend those that make use of environmental changes to reduce the amount of willpower necessary to achieve healthy behavior. Ultimately, the most effective policies will promote health rather than any arbitrary level of weight

Taking A Stand: The Effects Of Standing Desks On Task Performance And Engagement

Time spent sitting is associated with negative health outcomes, motivating some individuals to adopt standing desk workstations. This study represents the first investigation of the effects of standing desk use on reading comprehension and creativity. In a counterbalanced, within-subjects design, 96 participants completed reading comprehension and creativity tasks while both sitting and standing. Participants self-reported their mood during the tasks and also responded to measures of expended effort and task difficulty. In addition, participants indicated whether they expected that they would perform better on work-relevant tasks while sitting or standing. Despite participants’ beliefs that they would perform worse on most tasks while standing, body position did not affect reading comprehension or creativity performance, nor did it affect perceptions of effort or difficulty. Mood was also unaffected by position, with a few exceptions: Participants exhibited greater task engagement (i.e., interest, enthusiasm, and alertness) and less comfort while standing rather than sitting. In sum, performance and psychological experience as related to task completion were nearly entirely uninfluenced by acute (~30-min) standing desk use. View Full-Tex

The Effect of Wearing an Obese Body Suit on Snack Food Consumption and Alcohol Consumption

A previous study showed that wearing an obese body suit results in increased snack food consumption. The aim of this study was to explore mechanisms that may explain the effect that wearing an obese body suit has on snack food consumption. We examined two potential explanations; that the psychosocial experience of being overweight resulted in stereotype consistent behaviour (overeating) or in impairments to self-control. Ninety-four women participated in a laboratory study in which they were asked to wear an obese body suit or control clothing in a public setting, before being given access to snack food and alcohol. Clothing condition had no effect on snack food or alcohol consumption. It is possible that the presence of alcohol in the taste test removed the previously observed effect of the obese body suit on snack food consumption

Equilibrium Statistical Mechanics of Fermion Lattice Systems

We study equilibrium statistical mechanics of Fermion lattice systems which require a different treatment compared with spin lattice systems due to the non-commutativity of local algebras for disjoint regions. Our major result is the equivalence of the KMS condition and the variational principle with a minimal assumption for the dynamics and without any explicit assumption on the potential. It holds also for spin lattice systems as well, yielding a vast improvement over known results. All formulations are in terms of a C*-dynamical systems for the Fermion (CAR) algebra with all or a part of the following assumptions: (I) The interaction is even with respect to the Fermion number. (Automatically satisfied when (IV) below is assumed.) (II) All strictly local elements of the algebra have the first time derivative. (III) The time derivatives in (II) determine the dynamics. (IV) The interaction is lattice translation invariant. A major technical tool is the conditional expectation from the total algebra onto the local subalgebra for any finite subset of the lattice, which induces a system of commuting squares. This technique overcomes the lack of tensor product structures for Fermion systems and even simplifies many known arguments for spin lattice systems.Comment: 103 pages, no figure. The Section 13 has become simpler and a problem in 14.1 is settled thanks to a referee. The format has been revised according to the suggestion of this and the other referee

A Schmidt number for density matrices

We introduce the notion of a Schmidt number of a bipartite density matrix, characterizing the minimum Schmidt rank of the pure states that are needed to construct the density matrix. We prove that Schmidt number is nonincreasing under local quantum operations and classical communication. We show that $k$-positive maps witness Schmidt number, in the same way that positive maps witness entanglement. We show that the family of states which is made from mixing the completely mixed state and a maximally entangled state have increasing Schmidt number depending on the amount of maximally entangled state that is mixed in. We show that Schmidt number {\it does not necessarily increase} when taking tensor copies of a density matrix $\rho$; we give an example of a density matrix for which the Schmidt numbers of $\rho$ and $\rho \otimes \rho$ are both 2.Comment: 5 pages RevTex, 1 typo in Proof Lemma 1 correcte

Different Types of Conditional Expectation and the Lueders - von Neumann Quantum Measurement

In operator algebra theory, a conditional expectation is usually assumed to be a projection map onto a sub-algebra. In the paper, a further type of conditional expectation and an extension of the Lueders - von Neumann measurement to observables with continuous spectra are considered; both are defined for a single operator and become a projection map only if they exist for all operators. Criteria for the existence of the different types of conditional expectation and of the extension of the Lueders - von Neumann measurement are presented, and the question whether they coincide is studied. All this is done in the general framework of Jordan operator algebras. The examples considered include the type I and type II operator algebras, the standard Hilbert space model of quantum mechanics, and a no-go result concerning the conditional expectation of observables that satisfy the canonical commutator relation.Comment: 10 pages, the original publication is available at http://www.springerlink.co

The closure of ideals of ℓ 1 (Σ) in its enveloping C*-algebra

If X X is a compact Hausdorff space and σ σ is a homeomorphism of X X , then an involutive Banach algebra ℓ 1 (Σ) ℓ1(Σ) of crossed product type is naturally associated with the topological dynamical system Σ=(X,σ) Σ=(X,σ) . We initiate the study of the relation between two-sided ideals of ℓ 1 (Σ) ℓ1(Σ) and  C ∗ (Σ) C∗(Σ) , the enveloping C ∗  C∗ -algebra C(X)⋊ σ Z C(X)⋊σZ of ℓ 1 (Σ) ℓ1(Σ) .  Among others, we prove that the closure of a proper two-sided ideal of ℓ 1 (Σ) ℓ1(Σ) in  C ∗ (Σ) C∗(Σ) is again a proper two-sided ideal of C ∗ (Σ) C∗(Σ) .Analysis and Stochastic