How necessary are randomized controlled trials?

Randomized controlled trials (RCTs) are often deemed the gold standard for testing new treatments. This belief in turn justifies recruiting patients into such trials even when it is suspected that a new treatment is superior – although patients in the control group are thereby denied what might be the better treatment, we cannot know that the treatment actually is better, the thought runs, without conducting an RCT. But Robert Northcott argues that RCTs are not always the best choice after all. Rather, like any other method, they can go wrong sometimes, in several different ways. The main alternative to them is historical studies, which try to assess a treatment’s effectiveness from data not drawn from trials. These too can go wrong in several ways, and in the past have acquired a bad reputation. However, that prejudice has become outdated. The truer picture, Northcott argues, is that sometimes one method is preferable, sometimes the other. Things must be decided case by case. It follows that the ethical ramifications of conducting an RCT also must be examined case by case; there is no one-size-fits-all answer. An especially striking and emotional example concerns ECMO, a treatment for newborn babies with life-threatening lung problems. Historical studies indicated that ECMO was a major breakthrough, offering hugely increased survival rates. But it was still insisted that it also be tested in RCTs, in the course of which many babies receiving the conventional treatment died. A properly nuanced view of RCTs suggests that these deaths were tragically unnecessary

Social support in people with chronic aphasia

Background & Aims : Stroke and aphasia can have a profound impact on people's social activities, and family and social relationships. This study looked at patterns of social support in people with chronic aphasia following stroke. It examined the relationship between social support and quality of life, exploring which aspects of social support (social network versus perceived social support) were most associated with health-related quality of life (HRQL). Methods & Procedures : A cross-sectional interview-based survey study was conducted. A cluster-sampling framework was used to recruit participants with chronic aphasia following stroke (> 1 year) from three different sites in the south-east of England. Measures included the Stroke and Aphasia Quality of Life Scale-39 item version (SAQOL-39), the MOS Social Support Survey (SSS), and a social network questionnaire. Descriptive statistics, correlation, t -tests, and ANOVAs were used as appropriate. Outcomes & Results : The results of those able to self-report (83 out of 95 participants, 87%) are reported here. In terms of social networks, the mode of the size of network was 4. Size of network was associated with HRQL for women only. Most participants (71%) reported they had the same amount of contact with their children following the stroke, while 64% reported they saw their friends less. Those who had the same level of contact with their family as before the stroke had the highest HRQL scores; those who saw them either less or more than before the stroke had lower HRQL. In terms of perceived social support, the SSS scores were negatively skewed with a mean (SD) of 3.69 (.95), suggesting that participants felt overall well supported. Two types of support were significantly correlated with HRQL: social companionship and informational support. Clinical implications : Therapy services for people with aphasia could consider ways to enhance social companionship and informational support as this may positively impact on HRQL. Implications could include complementing and supporting existing social networks, and facilitating access to information and social participation

CLS Bank: Managing Foreign Exchange Settlement Risk

In the foreign exchange market, where average daily turnover is in trillions of dollars and trades span time zones, legal systems, and domestic payments systems, participants take on various risks. The most serious risk is credit risk - the risk that one party will fail to pay. Central banks, private sector financial institutions, and domestic payments systems operators laboured for more than a decade to develop a multi-currency settlement system to deal with these risks. The result, the CLS Bank, began operations in September 2002. It virtually eliminates the credit risk inherent in foreign exchange transactions by providing a payment-versus-payment arrangement for settlement. The CLS Bank is regulated by the Federal Reserve Board in consultation with the central banks that have currencies settling through its system. At present there are seven currencies, including the Canadian dollar. The Bank of Canada acts as banker for the CLS Bank, providing it with a settlement account and making and receiving payments on its behalf through the Large Value Transfer System. With the participation and support of the world's largest foreign-exchange-dealing institutions, and growing membership, the CLS Bank has the potential to become the dominant global mechanism for settling foreign exchange transactions.

Degree of explanation

Partial explanations are everywhere. That is, explanations citing causes that explain some but not all of an effect are ubiquitous across science, and these in turn rely on the notion of degree of explanation. I argue that current accounts are seriously deficient. In particular, they do not incorporate adequately the way in which a cause’s explanatory importance varies with choice of explanandum. Using influential recent contrastive theories, I develop quantitative definitions that remedy this lacuna, and relate it to existing measures of degree of causation. Among other things, this reveals the precise role here of chance, as well as bearing on the relation between causal explanation and causation itself

Harm and causation

I propose an analysis of harm in terms of causation: harm is when a subject is caused to be worse off. The pay-off from this lies in the details. In particular, importing influential recent work from the causation literature yields a contrastive-counterfactual account. This enables us to incorporate harm’s multiple senses into a unified scheme, and to provide that scheme with theoretical ballast. It also enables us to respond effectively to previous criticisms of counterfactual accounts, as well as to sharpen criticisms of rival views

Common subbundles and intersections of divisors

Let V_0 and V_1 be complex vector bundles over a space X. We use the theory of divisors on formal groups to give obstructions in generalised cohomology that vanish when V_0 and V_1 can be embedded in a bundle U in such a way that V_0\cap V_1 has dimension at least k everywhere. We study various algebraic universal examples related to this question, and show that they arise from the generalised cohomology of corresponding topological universal examples. This extends and reinterprets earlier work on degeneracy classes in ordinary cohomology or intersection theory.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol2/agt-2-42.abs.htm