Diamond-free Families

Given a finite poset P, we consider the largest size La(n,P) of a family of subsets of $[n]:=\{1,...,n\}$ that contains no subposet P. This problem has been studied intensively in recent years, and it is conjectured that $\pi(P):= \lim_{n\rightarrow\infty} La(n,P)/{n choose n/2}$ exists for general posets P, and, moreover, it is an integer. For $k\ge2$ let \D_k denote the $k$-diamond poset $\{A< B_1,...,B_k < C\}$. We study the average number of times a random full chain meets a $P$-free family, called the Lubell function, and use it for P=\D_k to determine \pi(\D_k) for infinitely many values $k$. A stubborn open problem is to show that \pi(\D_2)=2; here we make progress by proving \pi(\D_2)\le 2 3/11 (if it exists).Comment: 16 page

Spectral radiometry and tropospheric aerosols: Report of panel

The term aerosols, as used here, refers to the haze, smoke, and dust that appear in the troposphere. The term does not refer to the hydrometeors in cumulus and stratus clouds but does include the sulfuric acid-water droplets which are assumed to predominate in the stratospheric aerosol layer. The aerosol properties that were measured from satellites and those which can be made in the near term (up to 1992) will be reviewed. The capabilities that will exist in the years 1992 to 2000, with implementation of EOS, are then discussed. Finally, a few words will be said concerning the potential for aerosol measurements for the decade after 2000

Striving to Practice What We Preach: Academics reflecting on teaching reflective practice

That reflection is part of the HRD academics’ continuing professional development is a powerful rhetoric. But to what extent are we guilty of hypocrisy? Inspired by the title and theme of the conference ‘HRD: Reflecting upon the Past, Shaping the Future’ this paper seeks to make a critically reflective statement on our own practice as HRD academics teaching and researching reflective practice. Researching ‘practising what we preach’, in the context of reflective practice, raises difficult questions but offers the potential for valuable insight into the HRD academics’ professional practice

Design approaches and materials processes for ultrahigh efficiency lattice mismatched multi-junction solar cells

In this study, we report synthesis of large area (>2cm^2), crack-free GaAs and GaInP double heterostructures grown in a multi-junction solar cell-like structure by MOCVD. Initial solar cell data are also reported for GaInP top cells. These samples were grown on Ge/Si templates fabricated using wafer bonding and ion implantation induced layer transfer techniques. The double heterostructures exhibit radiative emission with uniform intensity and wavelength in regions not containing interfacial bubble defects. The minority carrier lifetime of ~1ns was estimated from photoluminescence decay measurements in both double heterostructures. We also report on the structural characteristics of heterostructures, determined via atomic force microscopy and transmission electron microscopy, and correlate these characteristics to the spatial variation of the minority carrier lifetime

Reflective Practice as a Threshold Concept: Implications for Teaching and Learning

Threshold concepts have received considerable attention in the literature since their development by Meyer and Land (2003), but while there has been some interest in relation to their applicability to management and business disciplines, this has been limited and threshold concepts have yet ‘to significantly impact the field of management education (Hibbert and Cunliffe 2015). The aim of this paper is to explore the extent to which reflective practice can be considered as a threshold concept, with the scope of the study being graduate students who participated in postgraduate programmes in Human Resource Management and Development. The discussion draws on data from eighteen interviews with HR professionals who had undertaken a Masters or Postgraduate Diploma in HR at one of three participating universities. The findings show that the concept of ‘threshold’ is highly relevant to reflective practice and demonstrates that reflective practice in the broadest sense can offer considerable value to postgraduate management students in relation to supporting their learning of both the technical and behavioural elements of their studies. Furthermore the findings can offer deeper insights into the integration of formal teaching processes on reflective practice

Striving to practice what we preach: academics reflecting on teaching reflective practice.

That reflection is part of the HRD academics’ continuing professional development is a powerful rhetoric. But to what extent are we guilty of hypocrisy? Inspired by the title and theme of the conference ‘HRD: Reflecting upon the Past, Shaping the Future’ this paper seeks to make a critically reflective statement on our own practice as HRD academics teaching and researching reflective practice. Researching ‘practising what we preach’, in the context of reflective practice, raises difficult questions but offers the potential for valuable insight into the HRD academics’ professional practice

Combinatorial control of temporal gene expression in the Drosophila wing by enhancers and core promoters

Abstract Background The transformation of a developing epithelium into an adult structure is a complex process, which often involves coordinated changes in cell proliferation, metabolism, adhesion, and shape. To identify genetic mechanisms that control epithelial differentiation, we analyzed the temporal patterns of gene expression during metamorphosis of the Drosophila wing. Results We found that a striking number of genes, approximately 50% of the Drosophila transcriptome, exhibited changes in expression during a time course of wing development. While cis-acting enhancer sequences clearly correlated with these changes, a stronger correlation was discovered between core-promoter types and the dynamic patterns of gene expression within this differentiating tissue. In support of the hypothesis that core-promoter type influences the dynamics of expression, expression levels of several TATA-box binding protein associated factors (TAFs) and other core promoter-associated components changed during this developmental time course, and a testes-specific TAF (tTAF) played a critical role in timing cellular differentiation within the wing. Conclusions Our results suggest that the combinatorial control of gene expression via cis-acting enhancer sequences and core-promoter types, determine the complex changes in gene expression that drive morphogenesis and terminal differentiation of the Drosophila wing epithelium.http://deepblue.lib.umich.edu/bitstream/2027.42/112935/1/12864_2012_Article_4965.pd