Risk pathways for gonorrhea acquisition in sex workers: can we distinguish confounding from an exposure effect using a priori hypotheses?

The population distribution of sexually transmitted infections (STIs) varies broadly across settings. Although there have been many studies aiming to define subgroups at risk of infection that should be a target for prevention interventions by identifying risk factors, questions remain about how these risk factors interact, how their effects jointly influence the risk of acquisition, and their differential importance across populations. Theoretical frameworks describing the interrelationships among risk determinants are useful in directing both the design and analysis of research studies and interventions. In this article, we developed such a framework from a review looking at determinants of risk for STI acquisition, using gonorrhea as an index infection. We also propose an analysis strategy to interpret the associations found to be significant in uniform analyses of observational data. The framework and the hierarchical analysis strategy are of particular relevance in the understanding of risk formation and might prove useful in identifying determinants that are part of the causal pathway and therefore amenable to prevention strategies across populations

Characterization of radially symmetric finite time blowup in multidimensional aggregation equations,

This paper studies the transport of a mass $\mu$ in $\real^d, d \geq 2,$ by a flow field $v= -\nabla K*\mu$. We focus on kernels $K=|x|^\alpha/ \alpha$ for $2-d\leq \alpha<2$ for which the smooth densities are known to develop singularities in finite time. For this range This paper studies the transport of a mass $\mu$ in $\real^d, d \geq 2,$ by a flow field $v= -\nabla K*\mu$. We focus on kernels $K=|x|^\alpha/ \alpha$ for $2-d\leq \alpha<2$ for which the smooth densities are known to develop singularities in finite time. For this range we prove the existence for all time of radially symmetric measure solutions that are monotone decreasing as a function of the radius, thus allowing for continuation of the solution past the blowup time. The monotone constraint on the data is consistent with the typical blowup profiles observed in recent numerical studies of these singularities. We prove monotonicity is preserved for all time, even after blowup, in contrast to the case $\alpha >2$ where radially symmetric solutions are known to lose monotonicity. In the case of the Newtonian potential ($\alpha=2-d$), under the assumption of radial symmetry the equation can be transformed into the inviscid Burgers equation on a half line. This enables us to prove preservation of monotonicity using the classical theory of conservation laws. In the case $2 -d < \alpha < 2$ and at the critical exponent $p$ we exhibit initial data in $L^p$ for which the solution immediately develops a Dirac mass singularity. This extends recent work on the local ill-posedness of solutions at the critical exponent.Comment: 30 page

Kants view of space about 1769

Kant was trying t o hunt with the hounds and run with the hare. He was trying to show that space is prior to the sensuous manifold, and yet that space presupposes a synthesis. He was trying to show that the parts of space are dependent upon the whole, and yet to say that the whole of space is determined by a synthesis cf the parts. It cannot be done. His attempt to combine these views failed. His only alternative was the view of the Diss. that the conditions of synthesis can be entirely intellectual, and that the conditions of the resulting whole can be entirely sensitive. On such a view, sense and intellect are dogmatically assumed to be separate and complete in themselves. But in the Aₙₐ. where they are bound inseparably together, the assumption is false.These conflicting views of space in theCritique make clearer the two views of space in Diss. 15. In 1770, Kant could answer Euler s Question in two ways . Space is not abstracted from sensation; in reference to the sensible world, it is not abstracted at all. There is, however, an intellectual synthesis which yields it. It is determined by this synthesis. Kant reconciled these two answers by means of the dualism of 1770. To know the sensible world, the mind requires only intuitions. Knowledge of the sensible world is synthetic, and not analytic. On the other hand, to know the intelligible, real world, the mind requires only concepts . Knowledge of the intelligible world is analytic and not synthetic. These two kinds of knowledge do not overlap.In every section of Diss. 15. save two Kant treated the pure intuition of space as presented or contemplated, and not constructed. In two parts he treated it as yielded by an activity of the mind. By following out this assumption, he discovered the weakness in his dualism. At the end of the Corollary, he suggested that the concepts of space and time, which are not abstracted from sense, and which are not gained by reflection (like the usual general concepts) are abstracted. from an activity of the mind on the occasion of sensation. He assumed that an intellectual activity can yield a sensitive whole. After 1770, he realized that this is impossible. He realized, however, that the fault lay not in the assumption of an activity of the mind, but in the deeper assumption of a thoroughgoing dualism. The assumption of an activity of the mind must -- he realized -- be retained, but the dualism rejected. He could not isolate conception and intuition. There is an activity of t'he understanding which begins with the manifold of sense and which determines space. The understanding represents space as a pure manifold (in pure Mathematics) in contrast to the sensuous manifold; and as a pure form of the sensuous manifold (in applied Mathematics.) . At the end cf the Corollary to Diss. 15., Kant was correct in saying that there is an activity of the mind. He was wrong Only in regard to its nature. The rest of Diss. 15. is based upon the false assumption that there is no activity of the mini. Diss. 15., as a whole, is based upon the false assumption that conception and intuition can be isolated. The doctrine that space is prior to sensation is based also upon this false assumption. The doctrine that the whole of space determines the parts is based also upon it. The same is true of the doctrine that an infinite number of representations are in space instead of under it. Once Kant corrected this assumption, and joined conceptions and intuitions, the representations cf space and time are subjected to the conditions of conception as well as to the conditions of sense. He could preserve the doctrines of space in the Aes . only by reverting to the point of view of the Dissertation and separating conception from intuition. He would never have done this. He retained the views of the Aes., either because he did not realize that he had contradicted them; or because, realizing it, he knew that the alteration required was too far-reaching to be undertaken.Kant failed to unify his doctrines of space in the Critique. Space is either prior to the manifold of sense:- in which case, it is not determined by any kind of synthesis; or space is determined by synthesis which begins with the prior existing manifold cf sense. The first is the teaching of Diss. 15. A., and Aes.1., the second is the teaching of the Aₙₐ. Either space remains after the objects of sense have been abstracted, or nothing remains after they have been abstracted. The first is the view of Diss. 15. A., and Aes. 11; the second is the view of the Aₙₐ. Either the whole of space determines the parts:- in which case there is no synthesis; or the parts precede the whole, and it is determined by a synthesis of then. If the whole (aggregate) has been reached by a synthesis, then it cannot precede the parts, but is preceded and determined by them. If the synthesis is carried further, a new whole results, and what had been previously considered as the whole, is found to have been merely an aggregate, determined by the extent of the previous synthesis of the parts. Space cannot presuppose an activity of the understanding (even in pure Geometry) unless the parts determine the whole. This contradicts Diss. 15. C. n. and 15. cor. (first -paragraph). Space cannot presuppose an activity of the understanding unless particular representations cf space are under "space" and not in it. This contradicts Aes. B. IV

Elevated Paracellular Glucose Flux across Cystic Fibrosis Airway Epithelial Monolayers Is an Important Factor for Pseudomonas aeruginosa Growth.

People with cystic fibrosis (CF) who develop related diabetes (CFRD) have accelerated pulmonary decline, increased infection with antibiotic-resistant Pseudomonas aeruginosa and increased pulmonary exacerbations. We have previously shown that glucose concentrations are elevated in airway surface liquid (ASL) of people with CF, particularly in those with CFRD. We therefore explored the hypotheses that glucose homeostasis is altered in CF airway epithelia and that elevation of glucose flux into ASL drives increased bacterial growth, with an effect over and above other cystic fibrosis transmembrane conductance regulator (CFTR)-related ASL abnormalities. The aim of this study was to compare the mechanisms governing airway glucose homeostasis in CF and non-CF primary human bronchial epithelial (HBE) monolayers, under normal conditions and in the presence of Ps. aeruginosa filtrate. HBE-bacterial co-cultures were performed in the presence of 5 mM or 15 mM basolateral glucose to investigate how changes in blood glucose, such as those seen in CFRD, affects luminal Ps. aeruginosa growth. Calu-3 cell monolayers were used to evaluate the potential importance of glucose on Ps. aeruginosa growth, in comparison to other hallmarks of the CF ASL, namely mucus hyperviscosity and impaired CFTR-dependent fluid secretions. We show that elevation of basolateral glucose promotes the apical growth of Ps. aeruginosa on CF airway epithelial monolayers more than non-CF monolayers. Ps. aeruginosa secretions elicited more glucose flux across CF airway epithelial monolayers compared to non-CF monolayers which we propose increases glucose availability in ASL for bacterial growth. In addition, elevating basolateral glucose increased Ps. aeruginosa growth over and above any CFTR-dependent effects and the presence or absence of mucus in Calu-3 airway epithelia-bacteria co-cultures. Together these studies highlight the importance of glucose as an additional factor in promoting Ps. aeruginosa growth and respiratory infection in CF disease

Developing the structural capital of higher education institutions to support work based learning

This chapter considers issues related to the provision of work-based learning [WBL] programmes by higher education institutions and discusses these programmes using the concept of structural capital. ‘Structural capital’ is defined as the organising and structuring capability of the organisation as expressed in formal instruments, policies, regulations, procedures, codes, functional business units, task groups, committees or less formal culture, networks and practices (Stewart, 1997) that influence practices and procedures. Our experiences of operating work-based learning programmes in two very different higher education institutions provide illustrations of structural factors that enable and facilitate work-based learning. The discussion outlines the forms of work-based learning that both universities employ, and considers some key aspects of WBL delivery that are directly impacted upon by the structures and processes within institutions, and contribute to intra-institutional structural capital. A summary of practical examples is given as an appendix to the chapter

Cooperative Set Function Optimization Without Communication or Coordination

We introduce a new model for cooperative agents that seek to optimize a common goal without communication or coordination. Given a universe of elements V, a set of agents, and a set function f, we ask each agent i to select a subset Si ⊂ V such that the size of Si is constrained (i.e., |Si| < k). The goal is for the agents to cooperatively choose the sets Si to maximize the function evaluated at the union of these sets, ∪iSi; we seek max f(∪iSi). We assume the agents can neither communicate nor coordinate how they choose their sets. This model arises naturally in many real-world settings such as swarms of surveillance robots and colonies of foraging insects. Even for simple classes of set functions, there are strong lower bounds on the achievable performance of coordinating deterministic agents. We show, surprisingly, that for the fundamental class of submodular set functions, there exists a near-optimal distributed algorithm for this problem that does not require communication. We demonstrate that our algorithm performs nearly as well as recently published algorithms that allow full coordination