The Impact of Job-Embedded Professional Development Coaches on Teacher Practice.

The intent of this qualitative study was to understand the impact of job-embedded professional development coaches on teacher practice. Coaches in this study worked with teachers to plan lessons, model lessons with feedback, and disaggregate data. This qualitative study was conducted using interviews of coaches to gain their perceptions of the work they did with teachers and how this work influenced teacher practice. Teachers were interviewed to determine their perceptions of the impact coaches\u27 work had on their classroom practices. Analysis of the coaches and teachers\u27 reflective journals was also conducted to establish the participants\u27 perceptions of their work together and the impact on teacher practice. Several themes emerged from the data analysis that assisted the researcher in forming the theoretical framework for the study. All coaches and teachers interviewed reported feeling positive about the work they did together planning lessons, modeling lessons with feedback, and disaggregating data. The researcher identified several factors that promoted the coaches\u27 influence on teacher practice and several barriers that limited the coaches\u27 influence on teacher practice. Teachers also identified traits and actions of an effective coach. Based on the research all the teachers grew in various ways from the work they did with the coaches. Teachers reported changing their practices and attitudes as well as trying new approaches, strategies, and programs. They appreciated coaches\u27 help with classroom management, discipline, and emotional support. Some teachers gained confidence in their teaching abilities, increased their expectations of students, and allowed students to take charge of their own learning. They went deeper with their teaching and engaged more in reflective thinking about why they do things the way they do. Job-embedded coaching has the potential to influence teachers\u27 practices and subsequently student learning. Recommendations from study findings may assist teachers, coaches, and school leaders in building an effective coaching model

Variation in chlorophyll content per unit leaf area in spring wheat and implications for selection in segregating material

Reduced levels of leaf chlorophyll content per unit leaf area in crops may be of advantage in the search for higher yields. Possible reasons include better light distribution in the crop canopy and less photochemical damage to leaves absorbing more light energy than required for maximum photosynthesis. Reduced chlorophyll may also reduce the heat load at the top of canopy, reducing water requirements to cool leaves. Chloroplasts are nutrient rich and reducing their number may increase available nutrients for growth and development. To determine whether this hypothesis has any validity in spring wheat requires an understanding of genotypic differences in leaf chlorophyll content per unit area in diverse germplasm. This was measured with a SPAD 502 as SPAD units. The study was conducted in series of environments involving up to 28 genotypes, mainly spring wheat. In general, substantial and repeatable genotypic variation was observed. Consistent SPAD readings were recorded for different sampling positions on leaves, between different leaves on single plant, between different plants of the same genotype, and between different genotypes grown in the same or different environments. Plant nutrition affected SPAD units in nutrient poor environments. Wheat genotypes DBW 10 and Transfer were identified as having consistent and contrasting high and low average SPAD readings of 52 and 32 units, respectively, and a methodology to allow selection in segregating populations has been developed. © 2014 Hamblin et al

Complex Signatures of Natural Selection at the Duffy Blood Group Locus

The Duffy blood group locus (FY) has long been considered a likely target of natural selection, because of the extreme pattern of geographic differentiation of its three major alleles (FY*B, FY*A, and FY*O). In the present study, we resequenced the FY region in samples of Hausa from Cameroon (fixed for FY*O), Han Chinese (fixed for FY*A), Italians, and Pakistanis. Our goals were to characterize the signature of directional selection on FY*O in sub-Saharan Africa and to understand the extent to which natural selection has also played a role in the extreme geographic differentiation of the other derived allele at this locus, FY*A. The data from the FY region are compared with the patterns of variation observed at 10 unlinked, putatively neutral loci from the same populations, as well as with theoretical expectations from the neutral-equilibrium model. The FY region in the Hausa shows evidence of directional selection in two independent properties of the data (i.e., level of sequence variation and frequency spectrum), observations that are consistent with the FY*O mutation being the target. The Italian and Chinese FY data show patterns of variation that are very unusual, particularly with regard to frequency spectrum and linkage disequilibrium, but do not fit the predictions of any simple model of selection. These patterns may represent a more complex and previously unrecognized signature of positive selection

Relating imperatives to action

The aim of this chapter is to provide an analysis of the use of logically complex imperatives, in particular, imperatives of the form Do A1 or A2 and Do A, if B. We argue for an analysis of imperatives in terms of classical logic which takes into account the influence of background information on imperatives. We show that by doing so one can avoid some counter-intuitive results which have been associated with analyses of imperatives in terms of classical logic. In particular, I address Hamblin's observations concerning rule-like imperatives and Ross' Paradox. The analysis is carried out within an agent-based logical framework. This analysis explicates what it means for an agent to have a successful policy for action with respect to satisfying his or her commitments, where some of these commitments have been introduced as a result of imperative language use

Performance of Single Nucleotide Polymorphisms versus Haplotypes for Genome-Wide Association Analysis in Barley

Genome-wide association studies (GWAS) may benefit from utilizing haplotype information for making marker-phenotype associations. Several rationales for grouping single nucleotide polymorphisms (SNPs) into haplotype blocks exist, but any advantage may depend on such factors as genetic architecture of traits, patterns of linkage disequilibrium in the study population, and marker density. The objective of this study was to explore the utility of haplotypes for GWAS in barley (Hordeum vulgare) to offer a first detailed look at this approach for identifying agronomically important genes in crops. To accomplish this, we used genotype and phenotype data from the Barley Coordinated Agricultural Project and constructed haplotypes using three different methods. Marker-trait associations were tested by the efficient mixed-model association algorithm (EMMA). When QTL were simulated using single SNPs dropped from the marker dataset, a simple sliding window performed as well or better than single SNPs or the more sophisticated methods of blocking SNPs into haplotypes. Moreover, the haplotype analyses performed better 1) when QTL were simulated as polymorphisms that arose subsequent to marker variants, and 2) in analysis of empirical heading date data. These results demonstrate that the information content of haplotypes is dependent on the particular mutational and recombinational history of the QTL and nearby markers. Analysis of the empirical data also confirmed our intuition that the distribution of QTL alleles in nature is often unlike the distribution of marker variants, and hence utilizing haplotype information could capture associations that would elude single SNPs. We recommend routine use of both single SNP and haplotype markers for GWAS to take advantage of the full information content of the genotype data

Biodistribution of charged 17.1A photoimmunoconjugates in a murine model of hepatic metastasis of colorectal cancer

Optimizing photodynamic therapy involves attempting to increase both the absolute tumour content of photosensitizer and the selectivity between tumour and surrounding normal tissue. One reason why photodynamic therapy has not been considered suitable for treatment of metastatic tumours in the liver, is the poor selectivity of conventional photosensitizers for tumour compared to normal liver. This report details an alternative approach to increasing this selectivity by the use of antibody-targeted photosensitizers (or photoimmunoconjugates) to target intrahepatic tumours caused by human colorectal cancer cells in the nude mouse, and explores the role of molecular charge on the tumour-targeting efficiency of macromolecules. The murine monoclonal antibody 17.1A (which recognizes an antigen expressed on HT 29 cells) was used to prepare site-specific photoimmunoconjugates with the photosensitizer chlorine6. The conjugates had either a predominant cationic or anionic charge and were injected i.v. into tumour-bearing mice. Biodistribution 3 or 24 h later was measured by extraction of tissue samples and quantitation of chlorine6 content by fluorescence spectroscopy. The photoimmunoconjugates were compared to the polylysine conjugates in an attempt to define the effect of molecular charge as well as antibody targeting. The anionic 17.1A conjugate delivered more than twice as much photosensitizer to the tumour at 3 h than other species (5 times more than the cationic 17.1A conjugate) and had a tumour:normal liver ratio of 2.5. Tumour-to-liver ratios were greater than one for most compounds at 3 h but declined at 24 h. Tumour-to-skin ratios were high (> 38) for all conjugates but not for free chlorine6. Cationic species had a high uptake in the lungs compared to anionic species. The photoimmunoconjugates show an advantage over literature reports of other photosensitizers, which can result in tumour:normal liver ratios of less than 1. © 2000 Cancer Research Campaign http://www.bjcancer.co

Targeted photodestruction of human colon cancer cells using charged Dougherty chlorine6immunoconjugates

The goal of this study was to develop a strategy for the selective destruction of colorectal cancer cells. Towards this end, photoimmunoconjugates were prepared between the anti-colon cancer monoclonal antibody 17.1A and the photosensitizer (PS) chlorine6(ce6). Polylysine linkers bearing several ce6molecules were covalently attached in a site-specific manner to partially reduced IgG molecules, which allowed photoimmunoconjugates to bear either cationic or anionic charges. The conjugates retained immunoreactivity as shown by enzyme-linked immunosorbent assays and by competition studies with native antibody. The overall charge on the photoimmunoconjugate was an important determinant of PS delivery. The cationic photoimmunoconjugate delivered 4 times more ce6to the cells than the anionic photoimmunoconjugate, and both 17.1A conjugates showed, in comparison to non-specific rabbit IgG conjugates, selectivity for antigen-positive target cells. Illumination with only 3 J cm−2of 666 nm light reduced the number of colony forming cells by more than 90% for the cationic 17.1A conjugate and by 73% for the anionic 17.1A conjugate after incubation with 1 μM ce6equivalent of the respective conjugates. By contrast, 1 μM free ce6gave only a 35% reduction in colonies. These data suggest photoimmunoconjugates may have applications in photoimmunotherapy where destruction of colorectal cancer cells is required. © 2000 Cancer Research Campaig