Training the Fetal Immune System Through Maternal Inflammation-A Layered Hygiene Hypothesis.

Over the last century, the alarming surge in allergy and autoimmune disease has led to the hypothesis that decreasing exposure to microbes, which has accompanied industrialization and modern life in the Western world, has fundamentally altered the immune response. In its current iteration, the "hygiene hypothesis" suggests that reduced microbial exposures during early life restricts the production and differentiation of immune cells suited for immune regulation. Although it is now well-appreciated that the increase in hypersensitivity disorders represents a "perfect storm" of many contributing factors, we argue here that two important considerations have rarely been explored. First, the window of microbial exposure that impacts immune development is not limited to early childhood, but likely extends into the womb. Second, restricted microbial interactions by an expectant mother will bias the fetal immune system toward hypersensitivity. Here, we extend this discussion to hypothesize that the cell types sensing microbial exposures include fetal hematopoietic stem cells, which drive long-lasting changes to immunity

A 380 GHz SIS receiver using Nb/AlO(x)/Nb junctions for a radioastronomical balloon-borne experiment: PRONAOS

The superheterodyne detection technique used for the spectrometer instrument of the PRONAOS project will provide a very high spectral resolution (delta nu/nu = 10(exp -6)). The most critical components are those located at the front-end of the receiver: their contribution dominates the total noise of the receiver. Therefore, it is important to perform accurate studies for specific components, such as mixers and multipliers working in the submillimeter wave range. Difficulties in generating enough local oscillator (LO) power at high frequencies make SIS mixers very desirable for operation above 300 GHz. The low LO power requirements and the low noise temperature of these mixers are the primary reason for building an SIS receiver. This paper reports the successful fabrication of small (less than or equal to 1 sq micron) Nb/Al-O(x)/Nb junctions and arrays with excellent I-V characteristics and very good reliability, resulting in a low noise receiver performance measured in the 368/380 GHz frequency range

Resonant tunneling diodes as sources for millimeter and submillimeter wavelengths

High-quality Resonant Tunneling Diodes have been fabricated and tested as sources for millimeter and submillimeter wavelengths. The devices have shown excellent I-V characteristics with peak-to-valley current ratios as high as 6:1 and current densities in the range of 50-150 kA/cm(exp 2) at 300 K. Used as local oscillators, the diodes are capable of state of the art output power delivered by AlGaAs-based tunneling devices. As harmonic multipliers, a frequency of 320 GHz has been achieved by quintupling the fundamental oscillation of a klystron source

Some Exact Results on the Potts Model Partition Function in a Magnetic Field

We consider the Potts model in a magnetic field on an arbitrary graph $G$. Using a formula of F. Y. Wu for the partition function $Z$ of this model as a sum over spanning subgraphs of $G$, we prove some properties of $Z$ concerning factorization, monotonicity, and zeros. A generalization of the Tutte polynomial is presented that corresponds to this partition function. In this context we formulate and discuss two weighted graph-coloring problems. We also give a general structural result for $Z$ for cyclic strip graphs.Comment: 5 pages, late

Exact Results on Potts Model Partition Functions in a Generalized External Field and Weighted-Set Graph Colorings

We present exact results on the partition function of the $q$-state Potts model on various families of graphs $G$ in a generalized external magnetic field that favors or disfavors spin values in a subset $I_s = \{1,...,s\}$ of the total set of possible spin values, $Z(G,q,s,v,w)$, where $v$ and $w$ are temperature- and field-dependent Boltzmann variables. We remark on differences in thermodynamic behavior between our model with a generalized external magnetic field and the Potts model with a conventional magnetic field that favors or disfavors a single spin value. Exact results are also given for the interesting special case of the zero-temperature Potts antiferromagnet, corresponding to a set-weighted chromatic polynomial $Ph(G,q,s,w)$ that counts the number of colorings of the vertices of $G$ subject to the condition that colors of adjacent vertices are different, with a weighting $w$ that favors or disfavors colors in the interval $I_s$. We derive powerful new upper and lower bounds on $Z(G,q,s,v,w)$ for the ferromagnetic case in terms of zero-field Potts partition functions with certain transformed arguments. We also prove general inequalities for $Z(G,q,s,v,w)$ on different families of tree graphs. As part of our analysis, we elucidate how the field-dependent Potts partition function and weighted-set chromatic polynomial distinguish, respectively, between Tutte-equivalent and chromatically equivalent pairs of graphs.Comment: 39 pages, 1 figur

Computer self-efficacy and classroom practice : what is the correlation?

vii, 68 leaves : ill. ; 28 cm.The present technological focus in education is requiring teachers to become computer-literate so that they are better able to integrate computer technology into their teaching. This thesis examines teachers' leves of computer self-efficacy (one's belief in one's ability to use computers) to see if there is a correlation with computer self-efficacy and classroom practice. Current research suggest that one can use computer self-efficacy as a way of determing teachers' levels of willingness to use computers. Based on the distribution of a computer self-efficacy scale and a questionnaire designed to identify computer technology integration into teaching, this study shows the correlation between computer self-efficacy and classroom practice in a selection of schools in southern Alberta. The finding of the research show that there is a weak correlation (r=0.405) between CSE and classroom practice; while there is a moderate to strong correlation (r=0.62) between CSE and instructional practice. Interestingly, the correlations between CSE and each of the specific classroom uses listed in the survey were extremely weak. These correlation coefficients ranged from 0.0777-0.287. Only 14/87 of the teachers surveyed have not attended a computer course. However, out of those 14 teachers only 2 do not use the computer for classroom used. On the other hand, of the 73 teachers who have attended a computer course, 16 do not use the computer in classroom teaching. For this group of teachers, participating in a computer course did not appear to have an impact on classroom practice. Moreover, the reseach found that those teachers with high levels of CSE do not necessarily teach using computers. An exploration of change literature provides a framework for understanding these results, and help place in perspective the need to rethink guidelines for professional development, teacher education and classroom practice as they relate to computers in education

Does Student Performance in Introductory Economics and Business Courses Impact ETS Scores?

This study examines the impact of economics education on student performance on the Educational Testing Service Major Field Test in Business. We demonstrate that grades in introductory microeconomics and macroeconomics courses have a positive relationship with overall exam performance as well as sub-scores in most content areas of the test. Furthermore, we use a measure of “extranormal” ability in economics and demonstrate its positive relationship to test performance. “Extranormal” ability represents the portion of course grades that cannot be explained by prior academic achievement. Finally, we show that the relationship between “extranormal” ability and exam performance is much more limited for female students than for male students

On the Potts model partition function in an external field

We study the partition function of Potts model in an external (magnetic) field, and its connections with the zero-field Potts model partition function. Using a deletion-contraction formulation for the partition function Z for this model, we show that it can be expanded in terms of the zero-field partition function. We also show that Z can be written as a sum over the spanning trees, and the spanning forests, of a graph G. Our results extend to Z the well-known spanning tree expansion for the zero-field partition function that arises though its connections with the Tutte polynomial