“Unintended effects”: A theorem for complex systems

Unintended effects are well known to economists and sociologists and their consequences may be devastating. The main objective of this article is to formulate a mathematical theorem, based on Gödel's famous incompleteness theorem, in which it is shown, that from the moment deontical modalities (prohibition, obligation, permission, and faculty) are introduced into the social system, responses are allowed by the system that are not produced, however, prohibited responses or unintended effects may occur.

Intimate partner violence in older women in Spain: prevalence, health consequences, and service utilization

The purpose of this study is to estimate the prevalence of lifetime intimate partner violence (IPV) in older women and to analyze its effect on women's health and Healthcare Services utilization. Women aged 55 years and over (1,676) randomly sampled from Primary Healthcare Services around Spain were included. Lifetime IPV prevalence, types, and duration were calculated. Descriptive and multivariate procedures using logistic and multiple lineal regression models were used. Of the women studied, 29.4% experienced IPV with an average duration of 21 years. Regardless of the type of IPV experienced, abused women showed significantly poorer health and higher healthcare services utilization compared to women who had never been abused. The high prevalence detected long standing duration, negative health impact, and high healthcare services utilization, calling attention to a need for increased efforts aimed at addressing IPV in older women.

Consequences of Kondo exchange on quantum spins

When individual quantum spins are placed in close proximity to conducting substrates, the localized spin is coupled to the nearby itinerant conduction electrons via Kondo exchange. In the strong coupling limit this can result in the Kondo effect — the formation of a correlated, many body singlet state — and a resulting renormalization of the density of states near the Fermi energy. However, even when Kondo screening does not occur, Kondo exchange can give rise to a wide variety of other phenomena. In addition to the well known renormalization of the g factor and the finite spin decoherence and relaxation times, Kondo exchange has recently been found to give rise to a newly discovered effect: the renormalization of the single ion magnetic anisotropy. Here we put these apparently different phenomena on equal footing by treating the effect of Kondo exchange perturbatively. In this formalism, the central quantity is ρJ, the product of the density of states at the Fermi energy ρ and the Kondo exchange constant J. We show that perturbation theory correctly describes the experimentally observed exchange induced shifts of the single spin excitation energies, demonstrating that Kondo exchange can be used to tune the effective magnetic anisotropy of a single spin.

Violence against young women attending primary care services in Spain: prevalence and health consequences

Background. There are a significant number of studies assessing the negative health consequences of violence against women. However, a limited number of studies analyse the health consequences of violence committed against young women by different types of aggressors. Objectives. The goal of this study is to assess the prevalence of interpersonal violence against young women in Spain and analyse its impact on the physical and mental health of the victims. Methods. A total of 1076 women aged 18–25 years attending Spanish primary care services were selected. We estimated the prevalence of interpersonal violence and compared the health data and demographic characteristics of abused and non-abused young women, multi-logistic regression models were fitted. The Wald test was used to assess whether there were differences in the negative health consequences of intimate partner (IPV) versus non-IPV. Results. As many as 27.6% young women reported a history of abuse, of whom 42.7% had been assaulted by their partner, 41.1% by someone other than their partner and 16.2% both by their partner and another person. The distribution of social and demographic characteristics was similar for IPV and non-IPV victims. Young abused women were three times more likely to suffer psychological distress and have somatic complaints, and they were four times more likely to use medication as compared to non-abused women. Conclusion. Our results suggest that all forms of violence compromise young women’s health seriously. Including patients’ history of abuse in their health record may help make more informed clinical decisions and provide a more integrated care.