Transition from School to University Mathematics: Manifestations of Unresolved Commognitive Conflict in First Year Students’ Examination Scripts

We explore the transition from school to university through a commognitive (Sfard 2008) analysis of twenty-two students’ examination scripts from the end of year examination of a first year, year-long module on Sets, Numbers, Proofs and Probability in a UK mathematics department. Our analysis of the scripts relies on a preliminary analysis of the tasks and the lecturers’ (also exam setters’) assessment practices, and focuses on manifestations of unresolved commognitive conflict in students’ engagement with the tasks. Here we note four such manifestations concerning the students’ identification of and consistent work with: the appropriate numerical context of the examination tasks; the visual mediators and the rules of school algebra and Set Theory discourses; the visual mediators of the Probability and Set Theory discourses; and, with the visual mediators and rules of the Probability Theory discourse. Our analysis suggests that, despite lecturers’ attempts to assist students towards a smooth transition to the different discourses of university mathematics, students’ errors at the final examination reveal unresolved commognitive conflicts. A pedagogical implication of our analysis is that a more explicit and systematic presentation of the distinctive differences between these discourses, along with facilitation of the flexible moves between them, is needed

Banking and Financial Crises in United States History: What Guidance can History Offer Policymakers?

This paper assesses the validity of comparisons of the current financial crisis with past crises in the United States. We highlight aspects of two National Banking Era crises (the Panic of 1873 and the Panic of 1907) that are relevant for comparison with the Panic of 2008. In 1873, overinvestment in railroad debt and the default of railroad companies on that debt led to the failure of numerous brokerage houses, an antecedent to the modern investment bank. For the Panic of 1907, panic-related deposit withdrawals centered on the less regulated trust companies, which were less directly linked to the existing lender of last resort, similar to investment banks in 2008. The popular press has made numerous references to the banking crises (there were three main ones) of the Great Depression as relevant comparisons to the present crisis. This paper argues that such an analogy is inaccurate in general

The analysis of relapse-free survival curves: implications for evaluating intensive systemic adjuvant treatment regimens for breast cancer

Results of adjuvant dose intensification studies in patients with localised breast cancer have raised questions regarding the clinical usefulness of this treatment strategy. Here, we develop and fit a natural history model for the time to clinical tumour recurrence as a function of the number of involved lymph nodes, and derive plausible predictions of the effects of dose intensification under various conditions. The time to tumour recurrence is assumed to depend on the residual postoperative micrometastatic burden of tumour, the fractional reduction of residual tumour burden (RTB) by treatment, and the rate of regrowth of the RTB to a clinically detectable size. It is assumed that a proportion of micrometastatic tumours are unresponsive to adjuvant chemotherapy even at maximal dose intensity. Data fitted included the San Antonio Cancer Institute (SACI) database of untreated patients, and CALGB #9082, a study comparing a highly intensive and moderately intensity adjuvant regimen in patients with 10+ positive axillary nodes. The proportion of tumours unresponsive to maximally intensive adjuvant treatment is estimated to be 48% (29–67%). The estimated log kill for intermediate-dose therapy from CALGB #9082 was 6.5 logs, compared with 9 logs or greater for high-dose therapy. The model is consistent with a modest but nonnegligible advantage of dose intensification compared with standard therapies in patients with sensitive tumours who have 10+ positive axillary nodes, and suggests that much of this clinical benefit could be achieved using intermediate levels of treatment intensification. The model further suggests that, in patients with fewer than 10 involved axillary nodes, any advantage of treatment intensification over standard therapy would be much reduced, because in patients with smaller tumour burdens of sensitive tumour, a larger proportion of cures achievable with intensified therapy could be achieved as well with standard therapy

Vertical integration for full outsourcing: growth and internationalization of a portuguese packaging firm

Based on a case study of a Portuguese packaging firm, this paper examines how vertical integration of the supplier serves as a vehicle for the full outsourcing of the client firms' needs in a solution that reduces transaction costs, favors specialization, and permits small and mediumsized firms to develop competencies that may be exploited in a wide array of projects. Vertical integration by the supplier (a governance decision) is a strategic response to changes in the sourcing model of the clients. Client-supplier relationships have inter-spatial and inter-temporal value that surpasses spot market exchanges

Comparative Genomic Analysis of Vibrio diabolicus and Six Taxonomic Synonyms: A First Look at the Distribution and Diversity of the Expanded Species

Vibrio is a diverse genus of Gammaproteobacteria autochthonous to marine environments worldwide. Vibrio diabolicus and V. antiquarius were originally isolated from deep-sea hydrothermal fields in the East Pacific Rise. These species are closely related to members of the Harveyi clade (e.g., V. alginolyticus and V. parahaemolyticus) that are commonly isolated from coastal systems. This study reports the discovery and draft genome sequence of a novel isolate (Vibrio sp. 939) cultured from Pacific oysters (Crassostrea gigas). Questions surrounding the identity of Vibrio sp. 939 motivated a genome-scale taxonomic analysis of the Harveyi clade. A 49-genome phylogeny based on 1,109 conserved coding sequences and a comparison of average nucleotide identity (ANI) values revealed a clear case of synonymy between Vibrio sp. 939, V. diabolicus Art-Gut C1 and CNCM I-1629, V. antiquarius EX25 and four V. alginolyticus strains (E0666, FF273, TS13, and V2). This discovery expands the V. diabolicus species and makes available six additional genomes for comparative genomic analyses. The distribution of the expanded species is thought to be global given the range of isolation sources (horse mackerel, seawater, sediment, dentex, oyster, artemia and polycheate) and origins (China, India, Greece, United States, East Pacific Rise, and Chile). A subsequent comparative genomic analysis of this new eight-genome subclade revealed a high degree of individual genome plasticity and a large repertoire of genes related to virulence and defense. These findings represent a significant revision to the understanding of V. diabolicus and V. antiquarius as both have long been regarded as distinct species. This first look at the expanded V. diabolicus subclade suggests that the distribution and diversity of this species mirrors that of other Harveyi clade species, which are notable for their ubiquity and diversity

Photochromism and Electrochemistry of a Dithienylcyclopentene Electroactive Polymer

A bifunctional substituted dithienylcyclopentene photochromic switch bearing electropolymerisable methoxystyryl units, which enable immobilization of the photochromic unit on conducting substrates, is reported. The spectroscopic, electrochemical, and photochemical properties of a monomer in solution are compared with those of the polymer formed through oxidative electropolymerization. The electroactive polymer films prepared on gold, platinum, glassy carbon, and indium titanium oxide (ITO) electrodes were characterized by cyclic voltammetry, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). The thickness of the films formed is found to be limited to several monolayer equivalents. The photochromic properties and stability of the polymer films have been investigated by UV/vis spectroscopy, electrochemistry, and XPS. Although the films are electrochemically and photochemically stable, their mechanical stability with respect to adhesion to the electrode was found to be sensitive to both the solvent and the electrode material employed, with more apolar solvents, glassy carbon, and ITO electrodes providing good adhesion of the polymer film. The polymer film is formed consistently as a thin film and can be switched both optically and electrochemically between the open and closed state of the photochromic dithienylethene moiety.

“Swapping” Families: Serial Parenting and Economic Support for Children

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71408/1/j.1741-3737.2000.00111.x.pd

Composition of the Top Management Team and Firm International Diversification

This study investigates the impact of various top management team characteristics on firm international diversification. Relying on data from 126 firms in the electronics industry, we find that certain top management team characteristics are related to international expansion. Specifically, results indicate that lower average age, higher average tenure, higher average elite education, higher average international experience, and higher tenure heterogeneity are associated with firm international diversification. The study reinforces the importance of top management team composition in internationalization decisions and suggests further research in this context.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Hypersensitive to Red and Blue 1 and Its Modification by Protein Phosphatase 7 Are Implicated in the Control of Arabidopsis Stomatal Aperture

The stomatal pores are located on the plant leaf epidermis and regulate CO2 uptake for photosynthesis and the loss of water by transpiration. Their stomatal aperture therefore affects photosynthesis, water use efficiency, and agricultural crop yields. Blue light, one of the environmental signals that regulates the plant stomatal aperture, is perceived by the blue/UV-A light-absorbing cryptochromes and phototropins. The signal transduction cascades that link the perception of light to the stomatal opening response are still largely unknown. Here, we report two new players, Hypersensitive to Red and Blue 1 (HRB1) and Protein Phosphatase 7 (PP7), and their genetic and biochemical interactions in the control of stomatal aperture. Mutations in either HRB1 or PP7 lead to the misregulation of the stomatal aperture and reduce water loss under blue light. Both HRB1 and PP7 are expressed in the guard cells in response to a light-to-dark or dark-to-light transition. HRB1 interacts with PP7 through its N-terminal ZZ-type zinc finger motif and requires a functional PP7 for its stomatal opening response. HRB1 is phosphorylated in vivo, and PP7 can dephosphorylate HRB1. HRB1 is mostly dephosphorylated in a protein complex of 193 kDa in the dark, and blue light increases complex size to 285 kDa. In the pp7 mutant, this size shift is impaired, and HRB1 is predominately phosphorylated. We propose that a modification of HRB1 by PP7 under blue light is essential to acquire a proper conformation or to bring in new components for the assembly of a functional HRB1 protein complex. Guard cells control stomatal opening in response to multiple environmental or biotic stimuli. This study may furnish strategies that allow plants to enjoy the advantages of both constitutive and ABA-induced protection under water-limiting conditions