Genome sequence of the temperate bacteriophage PH10 from Streptococcus oralis

Exponential growing cultures of Streptococcus oralis strain OMZ 1038, isolated from human supragingival dental plaque, were found to release a bacteriophage (designated PH10) upon treatment with mitomycin C. The complete genome sequence of phage PH10 was determined. The genome was 31276bp in size and contained 54 open reading frames. The module encoding structural proteins was highly similar to that of Streptococcus pneumoniae prophage PhiSpn_3. The most abundant phage structural protein was encoded by ORF35 and was likely processed by proteolytic cleavage. The putative endolysin from PH10, which contained a muramidase domain and a choline-binding domain, was purified and shown to have lytic activity with S. oralis, S. pneumoniae and Streptococcus mitis, but not with other streptococcal specie

Instrumental variable estimation based on grouped data

The paper considers the estimation of the coefficients of a single equation in the presence of dummy intruments. We derive pseudo ML and GMM estimators based on moment restrictions induced either by the structural form or by the reduced form of the model. The performance of the estimators is evaluated for the non-Gaussian case. We allow for heteroscedasticity. The asymptotic distributions are based on parameter sequences where the number of instruments increases at the same rate as the sample size. Relaxing the usual Gaussian assumption is shown to affect the normal asymptotic distributions. As a result also recently suggested new specification tests for the validity of instruments depend on Gaussianity. Monte Carlo simulations confirm the accuracy of the asymptotic approach.

Instrumental Variable Estimation Based on Grouped Data

The paper considers the estimation of the coefficients of a single equation in the presence of dummy intruments. We derive pseudo ML and GMM estimators based on moment restrictions induced either by the structural form or by the reduced form of the model. The performance of the estimators is evaluated for the non-Gaussian case. We allow for heteroscedasticity. The asymptotic distributions are based on parameter sequences where the number of instruments increases at the same rate as the sample size. Relaxing the usual Gaussian assumption is shown to affect the normal asymptotic distributions. As a result also recently suggested new specification tests for the validity of instruments depend on Gaussianity. Monte Carlo simulations confirm the accuracy of the asymptotic approach.

Efficiency bounds for instrumental variable estimators under group-asymptotics

This paper introduces a general, formal treatment of dynamic constraints, i.e., constraints on the state changes that are allowed in a given state space. Such dynamic constraints can be seen as representations of "real world" constraints in a managerial context. The notions of transition, reversible and irreversible transition, and transition relation will be introduced. The link with Kripke models (for modal logics) is also made explicit. Several (subtle) examples of dynamic constraints will be given. Some important classes of dynamic constraints in a database context will be identified, e.g. various forms of cumulativity, non-decreasing values, constraints on initial and final values, life cycles, changing life cycles, and transition and constant dependencies. Several properties of these dependencies will be treated. For instance, it turns out that functional dependencies can be considered as "degenerated" transition dependencies. Also, the distinction between primary keys and alternate keys is reexamined, from a dynamic point of view.

Farmers’ upheaval, climate crisis and populism

This article aims to unravel underlying reasons for the enigmatic outburst of farmers’ fury that swept large parts of Europe in the autumn of 2019. It does so by focussing on the Netherlands where the upheaval was particularly striking. Farmers’ resentment against ‘agribashing’ was a common theme in the many protests. This refers to, and simultaneously delegitimizes, all critiques of the current organization of farming and the unequal international patterns in which it is embedded. The article argues that the currently emerging farmers’ movement basically represents a regressive populism. It ignores the many-sided crisis of agriculture (related to ever increasing use of nitrogen, pesticides and energy that contribute to the climate crisis and loss of biodiversity) and the politico-economic processes and unequal power relations underlying this. Although this movement creates many smoke screens, it is essentially fighting for the reproduction of the same order that makes a substantial contribution to these multiple crises. As international comparison shows, this new form of right-wing, rural populism reflects the degree to which entrepreneurial agriculture has internalized the logic of capital: it needs ongoing expansion, both for material and symbolic reasons. Peasant agriculture could provide a much needed counter-image to this. In practice, though, it is highly segmented and dispersed and is in urgent need of a new unifying device.</p

Hand-held Dynamo-metry

This study describes the application of a hand-held dynamometer that was designed to measure muscle strength in normal individuals and neurological patients in a simple way, comparable to manual muscle testing. Zie: Summar

Hand-held Dynamo-metry

This study describes the application of a hand-held dynamometer that was designed to measure muscle strength in normal individuals and neurological patients in a simple way, comparable to manual muscle testing. Zie: Summar

The Economics of Books

The tensions between books and book markets as expressions of culture and books as products in profit-making businesses are analysed and insights from the theory of industrial organisation are given. Governments intervene in the market for books through laws concerning prices of books, grants for authors and publishers, a lower value-added tax, public libraries and education in order to stimulate the diversity of books on offer, increase the density of retail outlets and to promote reading. An overview of the different ways by which countries differ in terms of market structures and government policies is given. Particular attention is paid to retail price maintenance. Due to differences between European countries it is not a good idea to harmonise European book policies. Our analysis suggests that the book market seems quite able to invent solutions to specific problems of the book trade and that, apart from promoting reading, there is little need for government intervention.books, publishers, authors, diversity, monopolistic competition, retail price maintenance, subsidies, libraries, internet