Does Retirement Kill You? Evidence from Early Retirement Windows

The effect that health has on the retirement decision has long been studied. We examine the reverse relationship, whether retirement has a direct impact on later-life health. To identify the causal relationship, we use early retirement window offers to instrument for retirement. We find no negative effects of early retirement on men’s health, and if anything, a temporary increase in self-reported health and improvements in health of highly educated workers. While this is consistent with previous literature using Social Security ages as instruments, we also find that anticipation of retirement might be important, and bias the previous estimates downwards.retirement;depression;self-reported health;heart attack;cancer;diabetes;instrumental variables

Accurate simulation estimates of phase behaviour in ternary mixtures with prescribed composition

This paper describes an isobaric semi-grand canonical ensemble Monte Carlo scheme for the accurate study of phase behaviour in ternary fluid mixtures under the experimentally relevant conditions of prescribed pressure, temperature and overall composition. It is shown how to tune the relative chemical potentials of the individual components to target some requisite overall composition and how, in regions of phase coexistence, to extract accurate estimates for the compositions and phase fractions of individual coexisting phases. The method is illustrated by tracking a path through the composition space of a model ternary Lennard-Jones mixture.Comment: 6 pages, 3 figure

Does practice shape the brain?

No abstract available

Flammability limits in flowing ethene-air-nitrogen mixtures: an experimental study

A large pilot plant was constructed to study the upper flammability limit of ethene-air-nitrogen mixtures under conditions of flow. The gas mixtures flowed through an explosion tube with a length of 3.0 m and a diameter of 21 mm. An electrically heated wire was used as ignition source. Experiments were performed at pressures of 5 and 10 bar, with gas temperatures between 25 and 300 °C and with the wire fixed horizontally and vertically.\ud \ud Three different phenomena are observed: negligible reaction, local reaction, and explosion. The negligible reaction region occurs at power supply rates to the wire below a critical value. Above this critical value either a local reaction or an explosion occurs. The critical oxygen concentration which separates the local reaction and explosion regimes depends on the experimental conditions: gas composition, pressure, temperature, wire size and orientation, and gas velocity. An increase in pressure increases the upper flammability limit. Also an increase in temperature causes an increase in the upper flammability limit and the results can be explained by assuming a constant flame temperature.\ud \ud Moreover, the upper flammability limit is influenced by the gas velocity. Under conditions of flow the explosion region becomes smaller, it shifts to higher oxygen concentrations. In practise this may mean that partial oxidation reactions can safely be operated at higher oxygen concentrations, provided gas flow rates are kept high

Pericyte-mediated regulation of capillary diameter: a component of neurovascular coupling in health and disease

Because regional blood flow increases in association with the increased metabolic demand generated by localised increases in neural activity, functional imaging researchers often assume that changes in blood flow are an accurate read-out of changes in underlying neural activity. An understanding of the mechanisms that link changes in neural activity to changes in blood flow is crucial for assessing the validity of this assumption, and for understanding the processes that can go wrong during disease states such as ischaemic stroke. Many studies have investigated the mechanisms of neurovascular regulation in arterioles but other evidence suggests that blood flow regulation can also occur in capillaries, because of the presence of contractile cells, pericytes, on the capillary wall. Here we review the evidence that pericytes can modulate capillary diameter in response to neuronal activity and assess the likely importance of neurovascular regulation at the capillary level for functional imaging experiments. We also discuss evidence suggesting that pericytes are particularly sensitive to damage during pathological insults such as ischaemia, Alzheimer’s disease and diabetic retinopathy, and consider the potential impact that pericyte dysfunction might have on the development of therapeutic interventions and on the interpretation of functional imaging data in these disorders

A single journal study : Malaysian Journal of Computer Science

Single journal studies are reviewed and measures used in the studies are highlighted. The following quantitative measures are used to study 272 articles published in Malaysian Journal of Computer Science, (1) the article productivity of the journal from 1985 to 2007, (2) the observed and expected authorship productivity tested using Lotka's Law of author productivity, identification and listing of core authors; (3) the authorship, co-authorship pattern by authors' country of origin and institutional affiliations; (4) the subject areas of research; (5) the citation analysis of resources referenced as well as the age and half-life of citations; the journals referenced and tested for zonal distribution using Bradford's law of journal scattering; the extent of web citations; and (6) the citations received by articles published in MJCS and impact factor of the journal based on information obtained from Google Scholar, the level of author and journal self-citation

Caring for Mom and Neglecting Yourself? The Health Effects of Caring for an Elderly Parent

We examine the physical and mental health effects of providing care to an elderly mother on the adult child caregiver. We address the endogeneity of the selection in and out of caregiving using an instrumental variable approach, and carefully control for baseline health and work status of the adult child using fixed effects and Arellano-Bond estimation techniques. Continued caregiving over time increases depressive symptoms for married women and married men. In addition, the increase in depressive symptoms is persistent for married men. Depressive symptoms for single men and women are not affected by continued caregiving. There is a small protective effect on the likelihood (10%) of having any heart conditions among married women who continue caregiving. Robustness checks confirm that the increase in depressive symptoms and decrease in likelihood of heart conditions can be directly attributable to caregiving behavior, and not due to a direct effect of the death of the mother. The initial onset of caregiving, by contrast, has no immediate effects on physical or mental health for any subgroup of caregivers.CES-D;depressive symptoms;heart conditions;elderly parents;informal care

Bibliometric studies on single journals: a review

This paper covers a total of 82 bibliometric studies on single journals (62 studies cover unique titles) published between 1998 and 2008 grouped into the following fields; Arts, Humanities and Social Sciences (12 items); Medical and Health Sciences (19 items); Sciences and Technology (30 items) and Library and Information Sciences (21 items). Under each field the studies are described in accordance to their geographical location in the following order, United Kingdom, United States and Americana, Europe, Asia (India, Africa and Malaysia). For each study, elements described are (a) the journal’s publication characteristics and indexation information; (b) the objectives; (c) the sampling and bibliometric measures used; and (d) the results observed. A list of journal titles studied is appended. The results show that (a)bibliometric studies cover journals in various fields; (b) there are several revisits of some journals which are considered important; (c) Asian and African contributions is high (41.4 of total studies; 43.5 covering unique titles), United States (30.4 of total; 31.0 on unique titles), Europe (18.2 of total and 14.5 on unique titles) and the United Kingdom (10 of total and 11 on unique titles); (d) a high number of bibliometrists are Indians and as such coverage of Indian journals is high (28 of total studies; 30.6 of unique titles); and (e) the quality of the journals and their importance either nationally or internationally are inferred from their indexation status

Uptake of purines in <i>Plasmodium falciparum</i>-infected human erythrocytes is mostly mediated by the human Equilibrative Nucleoside Transporter and the human Facilitative Nucleobase Transporter

&lt;b&gt;Background&lt;/b&gt;: Plasmodium parasites are unable to synthesize purines de novo and have to salvage them from the host. Due to this limitation in the parasite, purine transporters have been an area of focus in the search for anti-malarial drugs. Although the uptake of purines through the human equilibrative nucleoside transporter (hENT1), the human facilitative nucleobase transporter (hFNT1) and the parasite-induced new permeation pathway (NPP) has been studied, no information appears to exist on the relative contribution of these three transporters to the uptake of adenosine and hypoxanthine. Using the appropriate transporter inhibitors, the role of each of these salvage pathways to the overall purine transport in intraerythrocytic Plasmodium falciparum was systematically investigated. &lt;b&gt;Methods&lt;/b&gt;: The transport of adenosine, hypoxanthine and adenine into uninfected and P. falciparum-infected human erythrocytes was investigated in the presence or absence of classical inhibitors of the hFNT1, hENT1 and NPP. The effective inhibition of the various transporters by the classical inhibitors was verified using appropriate known substrates. The ability of high concentration of unlabelled substrates to saturate these transporters was also studied. &lt;b&gt;Results&lt;/b&gt;: Transport of exogenous purine into infected or uninfected erythrocytes occurred primarily through saturable transporters rather than through the NPP. Hypoxanthine and adenine appeared to enter erythrocytes mainly through the hFNT1 nucleobase transporter whereas adenosine entered predominantly through the hENT1 nucleoside transporter. The rate of purine uptake was approximately doubled in infected cells compared to uninfected erythrocytes. In addition, it was found that the rate of adenosine uptake was considerably higher than the rate of hypoxanthine uptake in infected human red blood cells (RBC). It was also demonstrated that furosemide inhibited the transport of purine bases through hFNT1. &lt;b&gt;Conclusion&lt;/b&gt;: Collectively, the data obtained in this study clearly show that the endogenous host erythrocyte transporters hENT1 and hFNT1, rather than the NPP, are the major route of entry of purine into parasitized RBC. Inhibitors of hENT1 and hFNT1, as well as the NPP, should be considered in the development of anti-malarials targeted to purine transport