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This paper examines the stability of egocentric networks as reported over time using a novel touchscreen-based participant-aided sociogram. Past work has noted the instability of nominated network alters, with a large proportion leaving and reappearing between interview observations. To explain this instability of networks over time, researchers often look to structural embeddedness, namely the notion that alters are connected to other alters within egocentric networks. Recent research has also asked whether the interview situation itself may play a role in conditioning respondents to what might be the appropriate size and shape of a social network, and thereby which alters ought to be nominated or not. We report on change in these networks across three waves and assess whether this change appears to be the result of natural churn in the network or whether changes might be the result of factors in the interview itself, particularly anchoring and motivated underreporting. Our results indicate little change in average network size across waves, particularly for indirect tie nominations. Slight, significant changes were noted between waves one and two particularly among those with the largest networks. Almost no significant differences were observed between waves two and three, either in terms of network size, composition, or density. Data come from three waves of a Chicago-based panel study of young men who have sex with men.
In an effort to promote comparative research on pensions, the Gateway to Global Aging Data is developing harmonized cross-national panel data on pension benefits and retirement incentives. Past research has varied in how it predicts pension benefits for individuals who have not yet claimed their benefits when administrative data on earnings histories is unavailable. We use the Gateway data to evaluate several alternative approaches to computing prospective pension benefits using common survey questions and validate them against matched administrative data. We find that in some settings naïve measures of pension benefit growth from continued work and delayed benefit claiming can perform as well as measures based on administrative data. We also find that prospective benefit levels are sensitive to the heterogeneity of lifecycle earnings dynamics, resulting in substantial measurement error even after accounting for work history.
A large literature has established that the International Monetary Fund (IMF) is heavily politicized. We argue that this politicization has important consequences for international reserve accumulation and financial crises. The IMF generates moral hazard asymmetrically, reducing the expected costs of risky lending and policies for states that are politically influential vis-à-vis the institution. Using a panel data set covering 1980 to 2010, we show that proxies for political influence over the IMF are associated with outcomes indicative of moral hazard: lower international reserves and more frequent financial crises. We support our causal claims by applying the synthetic control method to Taiwan, which was expelled from the IMF in 1980. Consistent with our predictions, Taiwan's expulsion led to a sharp increase in precautionary international reserves and exceptionally conservative financial policies.
Preterm birth (PTB) has a global prevalence of 11.1% accounting for almost 15 million babies born each year before 37 weeks of gestation. It is a risk factor in over 50% of all neonatal deaths, which amounts to 1.1 million deaths annually. Preterm birth, especially at early gestational ages is associated with a high risk of long-term morbidity in survivors. Despite much research effort, PTB rates continue to rise, placing immense financial and emotional burden on society. In the US, the annual societal economic cost associated with PTB is $26.2 billion with an average of $51,600 being spent per infant born preterm. Preterm labour (PTL) accounts for 70% of these births, of which 25% are preceded by preterm pre-labour rupture of membranes (PPROM).
There are several significant challenges that must be overcome for PEM fuel cell commercialization such as electrode flooding, carbon corrosion, and significant cost due to the high loading of the platinum catalyst. Thus, a new structure is proposed for the cathode catalyst support consisting of Si/TiOx core/shell nanowires with branched structures, which has the potential to reduce electrode flooding, increase stability, and dramatically reduce the required Pt loading. In this study, Pt-coated Si/TiOx core/shell nanowires with and without branches are compared. The Pt surface area on supports with branch structures was calculated to be more than 4 times larger than on supports without branch structures, while keeping the Pt loading at only about 0.1 mg/cm2 (for the samples with branched structures). SEM, XRD, AES, and TEM were used to characterize the morphologies and structures of the as-prepared samples. Branched Si/TiOx core/shell nanowire structures may be a promising catalyst support to enable commercialization of highly cost-efficient PEM fuel cells and to promote an era of clean energy usage.
Background: High levels of multidimensional perfectionism may be dysfunctional in their own right and can also impact on the maintenance and treatment of Axis I psychiatric disorders. Aims: This paper sought to describe the behavioural expressions and imagery associated with perfectionism in a non-clinical sample. Method: Participants (n = 59) completed a newly developed questionnaire to assess behavioural expressions of perfectionism, and an adapted interview to assess perfectionism-related intrusive mental images. Results: The study found that those high in perfectionism took longer to complete tasks, experienced more checking and safety behaviour whilst carrying out tasks, and had greater trouble actually completing tasks compared to those low in perfectionism. In addition, those with higher levels of perfectionism experienced intrusive mental imagery, which was more distressing, harder to dismiss, and had more impact on behaviour than those with lower levels of perfectionism. Conclusions: This research provides an initial exploration of the specific behaviours and intrusive mental imagery associated with perfectionism. The new behavioural measure of perfectionism could prove useful clinically in the assessment of change; however, these findings are preliminary and warrant replication in a clinical sample in order to examine their treatment implications.
Correlative light and electron microscopy (CLEM) has facilitated study of intracellular trafficking. Routine application of CLEM would be advantageous for many laboratories but previously described techniques are particularly demanding, even for those with access to laser scanning confocal microscopy (LSCM) and transmission electron microscopy (TEM). We describe streamlined methods for TEM of green fluorescent protein (GFP)-labeled organelles after imaging by LSCM using gridded glass bottom imaging dishes. GFP-MAP 1A/1B LC3 (GFP-LC3) transfected cells were treated with rapamycin, fixed and imaged by LSCM. Confocal image stacks were acquired enabling full visualization of each GFP-LC3 labeled organelle. After LSCM, cells were embedded for TEM using a simplified two step method that stabilizes the glass bottom such that the block can be separated from the glass by mild heating. All imaging and TEM processing are performed in the same dish. The LSCM imaged cells were relocated on the block and serial sectioned. Correlation of LSCM, DIC, and TEM images was facilitated by cellular landmarks. All GFP labeled structures were successfully reidentified and imaged by serial section TEM. This method could make CLEM more accessible to nonspecialized laboratories with basic electron microscopy expertise and could be used routinely to confirm organelle localization of fluorescent puncta.
The effect of prior infection with cytomegalovirus (CMV) on progression of HIV disease in a cohort of 111 men with haemophilia was studied after 13 years followup. The relative hazards associated with CMV positivity on progression to AIDS, death and a CD4 count of 0·05 × 109/1 were 2·28, 2·42 and 2·34, respectively. CMV seropositive patients were significantly older than the seronegative and this was controlled for by using a Cox proportional hazards model. The relative hazards for the three endpoints decreased to 1·89, 1·82 and 1·93 respectively and were marginally non-significant (P = 0·05, 0·08 and 0·08 for the three endpoints respectively). We conclude that this cohort continues to show evidence of a ‘co-factor’ effect associated with prior infection with CMV which is confounded by age but not completely explained by age differences. The potential biological significance of these results is discussed in the context of recent controlled clinical trials which show a survival benefit from long-term high-dose acyclovir, a drug with activity in vivo against CMV and other herpesviruses.