Limiting Behaviour of the Mean Residual Life

In survival or reliability studies, the mean residual life or life expectancy is an important characteristic of the model. Here, we study the limiting behaviour of the mean residual life, and derive an asymptotic expansion which can be used to obtain a good approximation for large values of the time variable. The asymptotic expansion is valid for a quite general class of failure rate distributions--perhaps the largest class that can be expected given that the terms depend only on the failure rate and its derivatives.Comment: 19 page

The Relationship Between Body Composition and Baseball Performance in Division II Baseball Players

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Mild Cognitive Impairment in the Elderly is Associated with Volume Loss of the Cholinergic Basal Forebrain Region

Background Cholinergic neurons within the basal forebrain are assumed to be an early (preclinical) manifestation site of pathological changes in Alzheimer's disease (AD). Methods We used morphometric magnetic resonance imaging (MRI) to detect and quantify atrophic changes in the basal forebrain of subjects suffering from amnestic mild cognitive impairment (aMCI). Three Tesla magnetic resonance (MR) data of 26 aMCI patients, 46 cognitively normal elderly control subjects (CO), and 12 patients suffering from Alzheimer's dementia were analyzed, including segmentation and quantification of brain tissue as well as a segmentation of basal forebrain structures (substantia innominata [SI]). Results We found the volume of the SI to be significantly different between groups in that control subjects showed the largest SI volumes, followed by aMCI and AD patients. Conclusions These results are in line with the hypothesis that cell loss within the cholinergic basal forebrain regions occurs already in the early (predementia) stage of AD. In vivo quantification of these changes might be of use as a novel neuroimaging marker of cholinergic neurodegeneration in AD

Housing prices and multiple employment nodes: is the relationship nonmonotonic?

Standard urban economic theory predicts that house prices will decline with distance from the central business district. Empirical results have been equivocal, however. Disjoints between theory and empirics may be due to a nonmonotonic relationship between house prices and access to employment arising from the negative externalities associated with proximity to multiple centres of employment. Based on data from Glasgow (Scotland), we use gravity-based measures of accessibility estimated using a flexible functional form that allows for nonmonotonicity. The results are thoroughly tested using recent advances in spatial econometrics. We find compelling evidence of a nonmonotonic effect in the accessibility measure and discuss the implications for planning and housing policy

Treating hummingbirds as feathered bees : a case of ethological cross-pollination

Hummingbirds feed from hundreds of flowers every day. The properties of these flowers provide these birds with a wealth of information about colour, space and time to guide how they forage. To understand how hummingbirds might use this information, researchers have adapted established laboratory paradigms for use in the field. In recent years, however, experimental inspiration has come less from other birds, and more from looking at other nectar-feeders, particularly honeybees and bumblebees, which have been models for foraging behaviour and cognition for over a century. In a world in which the cognitive abilities of bees regularly make the news, research on the influence of ecology and sensory systems on bee behaviour is leading to novel insights in hummingbird cognition. As methods designed to study insects in the laboratory are being applied to hummingbirds in the field, converging methods can help us identify and understand convergence in cognition, behaviour and ecology.PostprintPeer reviewe

Receptor-targeted lentiviral vectors are exceptionally sensitive toward the biophysical properties of the displayed single-chain Fv

An increasing number of applications require the expression of single-chain variable fragments (scFv) fusion proteins in mammalian cells at the cell surface membrane. Here we assessed the CD30-specific scFv HRS3, which is used in immunotherapy, for its ability to retarget lentiviral vectors (LVs) to CD30 and to mediate selective gene transfer into CD30-positive cells. Fused to the C-terminus of the type-II transmembrane protein hemagglutinin (H) of measles virus and expressed in LV packaging cells, gene transfer mediated by the released LV particles was inefficient. A series of point mutations in the scFv framework regions addressing its biophysical properties, which substantially improved production and increased the melting temperature without impairing its kinetic binding behavior to CD30, also improved the performance of LV particles. Gene transfer into CD30-positive cells increased ∼100-fold due to improved transport of the H-scFv protein to the plasma membrane. Concomitantly, LV particle aggregation and syncytia formation in packaging cells were substantially reduced. The data suggest that syncytia formation can be triggered by trans-cellular dimerization of H-scFv proteins displayed on adjacent cells. Taken together, we show that the biophysical properties of the targeting ligand have a decisive role for the gene transfer efficiency of receptor-targeted LV

Matrix product decomposition and classical simulation of quantum dynamics in the presence of a symmetry

We propose a refined matrix product state representation for many-body quantum states that are invariant under SU(2) transformations, and indicate how to extend the time-evolving block decimation (TEBD) algorithm in order to simulate time evolution in an SU(2) invariant system. The resulting algorithm is tested in a critical quantum spin chain and shown to be significantly more efficient than the standard TEBD.Comment: 5 pages, 4 figure

The Ethics of Corporate Governance

How should corporate directors determine what is the right decision? For at least the past 30 years the debate has raged as to whether shareholder value should take precedence over corporate social responsibility when crucial decisions arise. Directors face pressure, not least from ethical investors, to do the good thing when they seek to make the right choice. Corporate governance theory has tended to look to agency theory and the need of boards to curb excessive executive power to guide directors' decisions. While useful for those purposes, agency theory provides only limited guidance. Supplementing it with the alternatives - stakeholder theory and stewardship theory - tends to put directors in conflict with their legal obligations to work in the interests of shareholders. This paper seeks to reframe the discussion about corporate governance in terms of the ethical debate between consequential, teleological approaches to ethics and idealist, deontological ones, suggesting that directors are - for good reason - more inclined toward utilitarian judgments like those underpinning shareholder value. But the problems with shareholder value have become so great that a different framework is needed: strategic value, with an emphasis on long-term value creation judged from a decidedly utilitarian standpoint

Health-related preferences of older patients with multimorbidity: An evidence map

Objectives To systematically identify knowledge clusters and research gaps in the health-related preferences of older patients with multimorbidity by mapping current evidence.Design Evidence map (systematic review variant).Data sources MEDLINE, EMBASE, PsycINFO, PSYNDEX, CINAHL and Science Citation Index/Social Science Citation Index/-Expanded from inception to April 2018.Study selection Studies reporting primary research on health-related preferences of older patients (mean age ≥60 years) with multimorbidity (≥2 chronic/acute conditions).Data extraction Two independent reviewers assessed studies for eligibility, extracted data and clustered the studies using MAXQDA-18 content analysis software.Results The 152 included studies (62% from North America, 28% from Europe) comprised 57 093 patients overall (range 9–9105). All used an observational design except for one interventional study: 63 (41%) were qualitative (59 cross-sectional, 4 longitudinal), 85 (57%) quantitative (63 cross-sectional, 22 longitudinal) and 3 (2%) used mixed methods. The setting was specialised care in 85 (56%) and primary care in 54 (36%) studies. We identified seven clusters of studies on preferences: end-of-life care (n=51, 34%), self-management (n=34, 22%), treatment (n=32, 21%), involvement in shared decision making (n=25, 17%), health outcome prioritisation/goal setting (n=19, 13%), healthcare service (n=12, 8%) and screening/diagnostic testing (n=1, 1%). Terminology (eg, preferences, views and perspectives) and concepts (eg, trade-offs, decision regret, goal setting) used to describe health-related preferences varied substantially between studies.Conclusion Our study provides the first evidence map on the preferences of older patients with multimorbidity. Included studies were mostly conducted in developed countries and covered a broad range of issues. Evidence on patient preferences concerning decision-making on screening and diagnostic testing was scarce. Differences in employed terminology, decision-making components and concepts, as well as the sparsity of intervention studies, are challenges for future research into evidence-based decision support seeking to elicit the preferences of older patients with multimorbidity and help them construct preferences.Trial registration number Open Science Framework (OSF): DOI 10.17605/OSF.IO/MCRWQ

Belief aggregation in financial markets and the nature of price fluctuations

We present a model of financial markets, where the belief of the market, expressed by a normal distribution over asset returns, is formed by aggregating in a dynamically consistent way individual subjective beliefs of the market participants, which are likewise assumed to follow normal distributions. We apply this model to a market of traders with standard CARA preferences with the aim of identifying an intrinsic source of price fluctuations. We find that asset prices depend on both Gaussian parameters mean and variance of the market belief, but argue that the latter changes slower than the former. Consequently, price fluctuations are dominated by the covariance matrix of the market participants’ subjective beliefs about expected asset returns