Washback or backwash? Revisiting the status quo of washback and test impact in EFL contexts

It has been argued in the literature on (language) testing that any act of testing/assessment can impact (a) educators’ curriculum design, (b) teachers’ teaching practices, and (c) students’ learning behaviors. This quality of any given testing situation or act of assessment has been called washback, or backwash if you will. Washback falls into the two categories of positive or negative—that is, beneficial or harmful. After an overview of the existing scholarly knowledge on washback, this paper argues that washback is not necessarily a test quality. Drawing on the notion of test method facets, the paper lends support to claims that see washback as a main function of teaching, learning, and policy-making situations or conditions rather than a quality of any given test. The paper also argues that the concepts of facet design and analysis including formal research designs, structural hypothesis testing, and measurement are inevitable and inescapable in any comprehensive model of washback. A possible borderline between backwash and washback is also proposed.

A Conserved Hydrophobic Moiety and Helix–Helix Interactions Drive the Self-Assembly of the Incretin Analog Exendin-4

Exendin-4 is a pharmaceutical peptide used in the control of insulin secretion. Structural information on exendin-4 and related peptides especially on the level of quaternary structure is scarce. We present the first published association equilibria of exendin-4 directly measured by static and dynamic light scattering. We show that exendin-4 oligomerization is pH dependent and that these oligomers are of low compactness. We relate our experimental results to a structural hypothesis to describe molecular details of exendin-4 oligomers. Discussion of the validity of this hypothesis is based on NMR, circular dichroism and fluorescence spectroscopy, and light scattering data on exendin-4 and a set of exendin-4 derived peptides. The essential forces driving oligomerization of exendin-4 are helix–helix interactions and interactions of a conserved hydrophobic moiety. Our structural hypothesis suggests that key interactions of exendin-4 monomers in the experimentally supported trimer take place between a defined helical segment and a hydrophobic triangle constituted by the Phe22 residues of the three monomeric subunits. Our data rationalize that Val19 might function as an anchor in the N-terminus of the interacting helix-region and that Trp25 is partially shielded in the oligomer by C-terminal amino acids of the same monomer. Our structural hypothesis suggests that the Trp25 residues do not interact with each other, but with C-terminal Pro residues of their own monomers.

Inter-Molecular Electrostatic Interactions Stabilizing the Structure of the PD-1/PD-L1 Axis: A Structural Evolutionary Perspective

PD-1/PD-L1 axis is one key therapeutic target against tumor cell immune escape. Structurally essential to the PD-1/PD-L1-linked immune escape is the binding interface of the PD-1/PD-L1 complex structure. Incorporating currently available PD-1/PD-L1-related experimental structures, this article unveils two sets of experimentally observed inter-molecular electrostatic interactions which stabilize the binding interface of the PD-1/PD-L1 complex structure. For the first time, this article proposes an evolutionary structural hypothesis that, as a result of natural selection, PD-1 is able to genetically mutate itself to structurally disrupt the PD-1/PD-L1 axis towards the restoration of T cell-mediated anti-tumor immunity.

Sichtbackstein des 19. Jahrhunderts

Abstract19th century brick façades between craft and industrialization: Towards an onsite reading of traces.Brick facades are one of the characteristic ingredients of 19th century architecture. They became ubiquitous during the period. The spread of visible brick and the development of heat-insulating façade claddings are intimately connected to the industrialization of the brick production, providing new moulding techniques such as extrusion, and new products such as hollow bricks. The present article presents the main steps of innovation, based on a review of contemporary technical literature, and establishes the direct link to traces which can be observed on site, providing necessary information for a first assessment, coarse dating and structural hypothesis on the basis of a visual inspection.

The Impact of Intergroup Helping on Third Parties’ Perceptions of Group Reputation

We investigated the consequences of intergroup helping for both the offering and the receiving group’s reputation in the eyes of third parties. In two experiments (N = 116 and N = 78), observers were presented with a group that offered versus requested help. Observers’ status beliefs confirmed the emergence of a status hierarchy that favored the group that offered help. Study 2 demonstrated that the newly emerged status differential quickly solidified. In particular, observers judged the help-offering group as more attractive and allocated more resources to this group. Consistent with the social structural hypothesis on stereotype content, attributions of competence were more relevant for groups’ reputation than attributions of warmth. We discuss the implications of our findings for societies comprising diverse groups.