We give an example of a countable theory $T$ such that for every cardinal $\lambda \geq \aleph_2$ there is a fully indiscernible set $A$ of power $\lambda$ such that the principal types are dense over $A$, yet there is no atomic model of $T$ over $A$. In particular, $T$ is a theory of size $\lambda$ where the principal types are dense, yet $T$ has no atomic model.

If T has only countably many complete types, yet has a type of infinite multiplicity then there is a c.c.c. forcing notion Q such that, in any Q-generic extension of the universe, there are non-isomorphic models M 1 and M 2 of T that can be forced isomorphic by a c.c.c. forcing. We give examples showing that the hypothesis on the number of complete types is necessary and what happens if `c.c.c.' is replaced by other cardinal-preserving adjectives. We also give (...) an example showing that membership in a pseudo-elementary class can be altered by very simple cardinal-preserving forcings. (shrink)

Intrusive agricultural experimentspublished in New Zealand in the last five yearsare reviewed in terms of the degree of animalsuffering involved, and the necessity for thissuffering in relation to research findings.When measured against animal welfare criteriaof the Ministry of Agriculture, thirty-sixstudies inflicted ``severe'' or ``very severe''suffering. Many of these experiments hadquestionable short-term applications, had anapplication restricted to agriculturalproduction or economic growth, or could havebeen modified to prevent or reduce suffering.

This paper aims to outline the ethical concerns regarding the use of antidepressant medication in children and adolescents. Recent debates surrounding this issue have focused on the link between selective serotonin reuptake inhibitor use and an increased risk of suicidal thinking/behaviour, and weighed that against the benefit of the alleviation of depressive symptoms. It is argued here that such an approach is simplistic. There are several serious risks surrounding antidepressant use in the young that ought to be included in the (...) equation, along with a consideration of the neuroethical concerns surrounding pharmacotherapy for affective disorders. Using the precautionary principle as a framework for analysis it is concluded that the risks are sufficiently serious and plausible that the prescribing of antidepressant medication to the young ought to be severely restricted; further it is imperative that the child and their parents are made fully aware of the risks, short-term and long-term, involved. (shrink)

A class K of structures is controlled if for all cardinals λ, the relation of L∞,λ-equivalence partitions K into a set of equivalence classes . We prove that no pseudo-elementary class with the independence property is controlled. By contrast, there is a pseudo-elementary class with the strict order property that is controlled 69–88).

A class K of structures is controlled if, for all cardinals λ, the relation of L ∞,λ-equivalence partitions K into a set of equivalence classes (as opposed to a proper class). We prove that the class of doubly transitive linear orders is controlled, while any pseudo-elementary class with the ω-independence property is not controlled.

Although there has been critical analysis of how the informed consent process functions in relation to participation in research and particular ethical 'dilemmas', there has been little examination of consenting to more routine medical procedures. We report a qualitative study of 25 women who consented to surgery. Of these, nine were ambivalent or opposed to having an operation. When faced with a consent form, women's accounts suggest that they rarely do anything other than obey professionals' requests for a signature. An (...) interactionist analysis suggests that women's capacity to act is reduced by the hospital structure of tacit, socially-imposed rules of conduct. Bourdieu's concepts of habitus, capital and symbolic power/violence show how the practical logic that women apply confers a 'sense of place' relative to professionals. Women experience deficits in capital that constrain their ability to exercise choice. This work demonstrates the weakness of the consent process as a safeguard of autonomy. (shrink)

Although activities in basic and applied research in developing countries (DCs) are guided by universal scientific principles, there are important differences in the way in which science is practiced from that of the industrialized world. Isolation from the mainstream of scientific activity, the need for the development of an indigenous scientific capacity, the lack of a critical mass of researchers with respect to most fields of knowledge, and the urgency of developing better and more efficient communication channels, are some of (...) the aspects that set apart the scientific activity of the developing world. In particular, the need to develop local "new" science aimed at solving pressing problems of a local nature suggests the existence of a different set of conditions from those found in scientifically-advanced countries. In the present article we look at the ways the special circumstances of science in DCs will affect the application of evaluation criteria, using bibliometric data on research in Mexico as an example. (shrink)

We formulate and analyze the dynamics of an influenza pandemic model with vaccination and treatment using two preventive scenarios: increase and decrease in vaccine uptake. Due to the seasonality of the influenza pandemic, the dynamics is studied in a finite time interval. We focus primarily on controlling the disease with a possible minimal cost and side effects using control theory which is therefore applied via the Pontryagin’s maximum principle, and it is observed that full treatment effort should be given while (...) increasing vaccination at the onset of the outbreak. Next, sensitivity analysis and simulations (using the fourth order Runge-Kutta scheme) are carried out in order to determine the relative importance of different factors responsible for disease transmission and prevalence. The most sensitive parameter of the various reproductive numbers apart from the death rate is the inflow rate, while the proportion of new recruits and the vaccine efficacy are the most sensitive parameters for the endemic equilibrium point. (shrink)

The number of discriminable colours is often assumed to be of the order of several million but the extent of detectable chromatic diversity present in individual natural scenes is an open question. Here, the aim was to estimate the number of discriminable colours seen in natural scenes. Hyperspectral data were obtained from a set of natural scenes over the range 400 - 720 nm at 10 nm intervals (Nascimento et al, 2002 Journal of the Optical Society of America A 19 (...) 1484 - 1490) and the representation of each scene in CIELAB space computed for all pixels of the image. The number of discriminable colours was estimated by counting the number of unit volumes in the three-dimensional volume defined by the scene when represented in CIELAB space. We found that the number of discriminable colours estimated in a scene could vary by an order of magnitude from scene to scene, but rarely exceeded 105, indicating a limited chromatic diversity. (shrink)

The age of digital technology has introduced new complications into the issues of fair and private use of copyrighted material. In fact, the question of private use of another's work has been transformed from a side issue in intellectual property jurisprudence into the very center of intellectual property discussions about rights and privileges in a networked world. This paper will explore the nuanced difference between fair and private use as articulated in the US and the European Copyright Laws. Part One (...) will explain the legal use and meaning of fair use and its justifications. We maintain that it is almost impossible to resolve the issue of the fair/private use's legal nature, if one has not previously resolved copyright's legal nature. Legal resolution of such conflicts, as we shall demonstrate, follows different rules, and the messages sent to users and authors vary greatly depending on the jurisdiction. Part Two will examine the issue of Private Use as Fair Use by Design. We will look at the impact of Digital Rights Management on fair use and explore if the nature of private use as fair use has changed because we are dealing with the protection of digital content. We will show that protecting digital works by code, via various digital rights management schemes is shrinking the public domain of information and restricting private use as fair use. (shrink)

The requirement of gauge invariance for the Schwinger-DeWitt equations, interpreted as a manifestly covariant quantum theory for the evolution of a system in spacetime, implies the existence of a five-dimensional pre-Maxwell field on the manifold of spacetime and “proper time” τ. The Maxwell theory is contained in this theory; integration of the field equations over τ restores the Maxwell equations with the usual interpretation of the sources. Following Schwinger's techniques, we study the Green's functions for the five-dimensional hyperbolic field equations (...) for both signatures ± [corresponding to O(4, 1) or O(3, 2) symmetry of the field equations] of the proper time derivative. The classification of the Green's functions follows that of the four-dimensional theory for “massive” fields, for which the “mass” squared may be positive or negative, respectively. The Green's functions for the five-dimensional field are then given by the Fourier transform over the “mass” parameter. We derive the Green's functions corresponding to the principal part ΔP and the homogeneous function Δ 1 ; all of the Green's functions can be expressed in terms of these, as for the usual field equations with definite mass. In the O(3, 2) case, the principal part function has support for x2⩾τ2, corresponding to spacelike propagation, as well as along the light cone x2=0 (for τ=0). There can be no transmission ofinformation in spacelike directions, with this propagator, since the Maxwell field, obtained by integration over τ, does not contain this component of the support. Measurements are characterized by such an integration. The spacelike field therefore can dynamically establish spacelike correlations. (shrink)

In this paper we will show that Hempel's covering law model can't deal very well with explanations that are based on incomplete knowledge. In particular the symmetry thesis, which is an important aspect of the covering law model, turns out to be problematic for these explanations. We will discuss an example of an electric circuit, which clearly indicates that the symmetry of explanation and prediction does not always hold. It will be argued that an alternative logic for causal explanation is (...) needed. And we will investigate to what extent non-monotonic epistemic logic can provide such an alternative logical framework. Finally we will show that our non-monotonic logical analysis of explanation is not only suitable for simple cases such as the electric circuit, but that it also sheds new light on more controversial causal explanations such as Milton Friedman's explanation of the business cycle. (shrink)