The development of amyloid beta protein deposits in the aged brain

The deposition of amyloid beta protein (Abeta) in the human brain and the generation of neurofibrillary tangles are the histopathological hallmarks of Alzheimer's disease. Accumulation of Abeta takes place in senile plaques and in cerebrovascular deposits as a result of an imbalance between Abeta production and clearance. This Review describes the different types of Abeta deposits, which can be distinguished by their morphology and by the hierarchical involvement of distinct areas of the brain in Abeta deposition. The role of intracellular Abeta in Abeta deposition and the mechanism of Abeta toxicity are also discussed.     

Endurance performance in masters athletes

Masters athletes are typically older than 35 years of age and systematically train for, and compete in, organized forms of sport specifically designed for older adults. They are motivated to participate in masters sport for a wide variety of reasons. Age-related declines in endurance performance are observed across the endurance sports of running, orienteering, rowing, and swimming. These declines are curvilinear from age 35 years until approximately age 60–70 years and exponential thereafter. The decline in endurance performance appears primarily due to an age-related decrease in VO_2max secondary to an age-related decrease in HR_max and possible age-related declines in stroke volume and arteriovenous oxygen difference. While performance velocity at lactate threshold decreases with age in masters endurance athletes, it appears to increase relative to VO_2max while exercise economy is maintained. There also appears an age-related decrease in active muscle mass, type II muscle fiber size, and blood volume that contribute to decreased endurance performance. However, research suggests that maintenance of training intensity and volume into older age may mediate the rate of age-related decline in VO_2max, stroke volume, arteriovenous oxygen difference, blood volume, and muscle mass in masters endurance athletes.     

On the Ghoudi,Khoudraji, and Rivest test for extreme‐value dependence

Ghoudi, Khoudraji & Rivest [The Canadian Journal of Statistics 1998;26:187–197] showed how to test whether the dependence structure of a pair of continuous random variables is characterized by an extreme‐value copula. The test is based on a U‐statistic whose finite‐ and large‐sample variance are determined by the present authors. They propose estimates of this variance which they compare to the jackknife estimate of Ghoudi, Khoudraji & Rivest ( 1998 ) through simulations. They study the finite‐sample and asymptotic power of the test under various alternatives. They illustrate their approach using financial and geological data. The Canadian Journal of Statistics © 2009 Statistical Society of Canada     

Mothers,fathers and children after divorce: The role of institutions

In recent years the increase in the divorce rate in many advanced countries and the predominance of female-headed families among the poor has generated much interest in the relationship between divorce and the welfare of mothers and children. In this paper I will review a small body of economic literature which has been recently developed in order to analyze the economic consequence of divorce on the welfare of fathers, mothers and children under alternative behavioral assumptions. Important economic and econometric issues arise from an analysis of welfare in non intact households as compared with intact households. In particular the focus is on the role that institutions play in post-divorce arrangements and important implications concerning policies for child support, custody, and visitation.Presidential Address of the Annual Congress of ESPE2000 held on June 15, 2000 in Bonn. I would like to thank Christopher Flinn, Rocio Ribero, Maristella Botticini and two anonymous referees for their helpful comments. Responsible editor: Alessandro Cigno.     

How Much Does Hiring and Firing Cost? Survey Evidence from a Sample of Italian Firms

We analyse the Italian labour market, which is typically considered to be highly regulated. We focus on the costs imposed on firms by the institutional environment in which they operate, and on the adjustment strategies that they pursue as a result. We have followed two complementary approaches: the analysis of the development of the laws relating to hiring and firing, together with a set of interviews of 61 manufacturing firms. This also allows us to quantify the extent of turnover costs on the total labour costs. Hiring costs, which include recruiting and training, range between 2.0 and 2.6 months of labour costs; firing costs range from less than half a monthly labour cost to 20 months of labour costs in cases of conflict.     

Soil-atmosphere exchange of carbon dioxide,methane and nitrous oxide in urban garden systems: impact of irrigation,fertiliser and mulch

Urban green spaces provide important ecosystem services, such as amenity, biodiversity, productivity, climate amelioration, hydrological and biogeochemical cycling. Intensively managed urban gardens can sequester carbon through vegetation growth and soil C increase, but may experience nitrous oxide (N₂O) emissions and reduced soil methane (CH₄) uptake from irrigation and fertiliser use. Soil atmosphere exchange of N₂O, CH₄ and carbon dioxide (CO₂) was measured in lawn and wood chip mulched garden areas in Melbourne, Australia in winter, spring and summer under various water and fertiliser regimes. Gas exchange before and after lawn fertiliser application was measured continuously for three weeks using an automated chamber system. Applying fertiliser led to a peak N₂O emission of >60 μg N m⁻² h⁻¹, but overall only weekly irrigation (10 mm) significantly increased mean soil N₂O emissions above that in other treatments. Under mulch, mean soil N₂O emissions (14.0 μg N m⁻² h⁻¹) were significantly smaller than from irrigated lawn (27.9 μg N m⁻² h⁻¹), whereas mean soil CH₄ uptake under mulch (−30.7 μg C m⁻² h⁻¹) was significantly greater (p < 0.01) than in any lawn treatment. Lawns were either a weak CH₄ sink or source. Soil C density (0–25 cm) under mulch (12.5 kg C m⁻²) was greater that under lawn (8.0 kg C m⁻²). On a carbon dioxide equivalent (CO₂-e) basis, soil N₂O emissions offset the benefits of soil CH₄ uptake. Mulched garden areas provide greatest C sequestration potential in soil and vegetation and the smallest non-CO₂ emissions, as soil CH₄ uptake offsets a large fraction of soil N₂O emissions. Results of this study suggest that reducing the irrigation and fertiliser application to lawns can help mitigate GHG emissions from urban garden systems, and increasing the area of mulched perennial garden beds can also provide net GHG benefits; however, this needs to be tested in other garden systems with different soil types and environmental conditions.     

Cognitive Deficits in Executive Functions and Decision-Making Impairments Cluster Gambling Disorder Sub-types

To identify Gambling Disorder (GD) subtypes, in a population of men seeking treatment for GD, according to specific executive function domains (i.e., cognitive flexibility, inhibition and working memory as well as decision making) which are usually impaired in addictive behaviors. A total of 145 males ranging from 18 to 65 years diagnosed with GD were included in this study. All participants completed: (a) a set of questionnaires to assess psychopathological symptoms, personality and impulsivity traits, and (b) a battery of neuropsychological measures to test different executive functioning domains. Two clusters were identified based on the individual performance on the neuropsychological assessment. Cluster 1 [n = 106; labeled as Low Impaired Executive Function (LIEF)] was composed by patients with poor results in the neuropsychological assessment; cluster 2 patients [n = 46; labeled as High Impaired Executive Function (HIEF)] presented significantly higher deficits on the assessed domains and performed worse than the ones of LIEF cluster. Regarding the characterization of these two clusters, patients in cluster 2 were significantly older, unemployed and registered higher mean age of GD onset than patients in cluster 1. Additionally, patients in cluster 2 also obtained higher psychopathological symptoms, impulsivity (in both positive and negative urgency as well as sensation seeking) and some specific personality traits (higher harm avoidance as well as lower self-directedness and cooperativeness) than patients in cluster 1. The results of this study describe two different GD subtypes based on different cognitive domains (i.e., executive function performance). These two GD subtypes display different impulsivity and personality traits as well as clinical symptoms. The results provide new insight into the etiology and characterization of GD and have the potential to help improving current treatments.     

Computing brains: learning algorithms and neurocomputation in the smart city

ABSTRACT

This article examines IBM’s ‘Smarter Education’ program, part of its wider ‘Smarter Cities’ agenda, focusing specifically on its learning analytics applications (based on machine learning algorithms) and cognitive computing developments for education (which take inspiration from neuroscience for the design of brain-like neural networks algorithms and neurocomputational devices). The article conceptualizes the relationship between learning algorithms, neuroscience, and the new learning spaces of the city by combining the notion of programmable ‘code/space’ with ideas about the ‘social life of the brain’ to suggest that new kinds of ‘brain/code/spaces’ are being developed where the environment itself is imagined to possess brain-like functions of learning and ‘human qualities’ of cognition performed by algorithmic processes. IBM’s ambitions for education constitute a sociotechnical imaginary of a ‘cognitive classroom’ where the practices associated with data analytics and cognitive computing in the smart city are being translated into the neuropedagogic brain/code/spaces of the school, with significant consequences for how learners are to be addressed and acted upon. The IBM imaginary of Smarter Education is one significant instantiation of emerging smart cities that are to be governed by neurocomputational processes modelled on neuroscientific insights into the brain’s plasticity for learning, and part of a ‘neurofuture’ in-the-making where nonconscious algorithmic ‘computing brains’ embedded in urban space are intended to interact with human cognition and brain functioning.     

Corporate social responsibility and conflicts of interest in the alcohol and gambling industries: a post‐political discourse?

The corporate pursuit of social goals – known as Corporate Social Responsibility or ‘CSR’ – has been subject to critique on a number of grounds. However, a hitherto underexplored potential consequence of CSR has been suggested in a recent paper by C. Garsten and K. Jacobsson (‘Post‐Political Regulation: Soft Power and Post‐political Visions in Global Governance’ (2013), Critical Sociology 39: 421–37). They suggest that CSR is part of an international trend towards ‘post‐political’ governance discourses, where an emphasis on different actors’ common goals obscures conflicts of interest, subverting the open political conflict necessary for a well‐functioning democracy. This paper examines whether such post‐political discourses – including an outright denial of conflict of interest – can be found within the alcohol and gambling industries, where conflicts of interest are likely to be particularly acute given the addictive nature of the goods/services in question. Based on interviews with CSR professionals in these industries in Italy, the UK, and at EU‐level, we do indeed find evidence of a post‐political discourse. In these discourses, alcohol/gambling industry staff deny potential conflicts of interest on the basis that any small benefits from sales to a small number of addicts are seen to be outweighed by the reputational damage that addicts cause. Crucially, however, this coexists with another, less post‐political discourse, where addictions CSR professionals emphasize ‘common ground’ as a basis for CSR, while accepting some instances of possible conflict of interest. Here interviewees make considerable efforts to differentiate good (sustainable) from bad (short‐term) self‐interest in order to stress the genuineness of their own actions. We conclude the paper by considering whether CSR embedded within a ‘common ground’ discourse still hides conflicts of interests and subverts democratic debate, or overcomes the problems identified by Garsten and Jacobsson.     

Parameter estimation of the flexible Weibull distribution for type I censored samples

Often in practice one is interested in the situation where the lifetime data are censored. Censorship is a common phenomenon frequently encountered when analyzing lifetime data due to time constraints. In this paper, the flexible Weibull distribution proposed in Bebbington et al. [A flexible Weibull extension, Reliab. Eng. Syst. Safety 92 (2007), pp. 719–726] is studied using maximum likelihood technics based on three different algorithms: Newton Raphson, Levenberg Marquardt and Trust Region reflective. The proposed parameter estimation method is introduced and proved to work from theoretical and practical point of view. On one hand, we apply a maximum likelihood estimation method using complete simulated and real data. On the other hand, we study for the first time the model using simulated and real data for type I censored samples. The estimation results are approved by a statistical test.