15,124 research outputs found
It’s driving her mad: gender differences in the effects of commuting on psychological well-being
In this paper, we seek to explore the effects of commuting time on the psychological well-being of men and women in the UK. We use annual data from the British Household Panel Survey in a fixed effects panel framework that includes variables known to determine well-being, as well as factors which may provide compensation for commuting such as income, job satisfaction and housing quality. Our results show that, even after all these variables are considered, commuting still has an important detrimental effect on the well-being of women, but not men, and this result is robust to numerous different specifications. We explore possible explanations for this gender difference and can find no evidence that it is due to women´s shorter working hours or weaker occupational position. Rather women´s greater sensitivity to commuting time seems to be a result of their larger responsibility for day-to-day household tasks, including childcare
Heterotopia in Networked Learning: Beyond the Shadow Side of Participation in Learning Communities
As it has evolved, networked learning (NL) has come to emphasise the importance of the collaborative learning aspects and possibilities of online learning. The importance assumed for 'collaboration based' forms of participation within NL has almost become ubiquitous and is frequently seen as an unquestionable good aspect - a utopian view of participation which does not acknowledge the 'shadow side' of participation in learning. In the paper we examine some of the darker sides of collaborative participation which in its extreme manifestations can be experienced as normative and, we suggest, a form of tyranny of the dominant and which instead of having a liberating effect, reinforces a form of oppression and control. We argue this is most likely to be the case in the absence of reflexivity and understanding of different ways and approaches to participation. We go on to suggest an alternative and potentially more productive perspective which, after Foucault, is a heterotopian one. A perspective that acknowledges and assumes disruption and which disturbs our customary notion of ourselves. Participation in heterotopian spaces is disturbing and ambiguous, but it offers a space in which to imagine, to desire and act differently
Patterns and rules for sensitivity and elasticity in population projection matrices
Sensitivity and elasticity analysis of population projection matrices (PPMs) are established tools in the analysis of structured populations, allowing comparison of the contributions made by different demographic rates to population growth. In some commonly used structures of PPM, however, there are mathematically inevitable patterns in the relative sensitivity and elasticity of certain demographic rates. We take a simulation approach to investigate these mathematical constraints for a range of PPM models. Our results challenge some previously proposed constraints on sensitivity and elasticity. We also identify constraints beyond those which have already been proven mathematically, and promote them as candidates for future mathematical proof. A general theme among these rules is that changes to the demographic rates of older or larger individuals have less impact on population growth than do equivalent changes among younger or smaller individuals. However, the validity of these rules in each case depends on the choice between sensitivity and elasticity, the growth rate of the population and the PPM structure used. If the structured population conforms perfectly to the assumptions of the PPM used to model it, the rules we describe represent biological reality, allowing us to prioritise management strategies in the absence of detailed demographic data. Conversely, if the model is a poor fit to the population (specifically; if demographic rates within stages are heterogeneous) such analyses could lead to inappropriate management prescriptions. Our results emphasise the importance of choosing a structured population model which fits the demographics of the population
Efficient Estimation of Conditional Asset Pricing Models
A semiparametric efficient estimation procedure is developed for the parameters of multivariate GARCH-in-mean models when the disturbances have a distribution that is assumed to be elliptically symmetric but is otherwise unrestricted. Under high level restrictions, the resulting estimator achieves the asymptotic semiparametric efficiency bound. The elliptical symmetry assumption allows us to avert the curse of dimensionality problem that would otherwise arise in estimating the unknown error distribution. This framework is suitable for the estimation and testing of conditional asset pricing models such as the conditional CAPM, and we apply our estimator in an empirical study of stock prices, with Monte Carlo simulation results also being reported. Nous développons un nouvel estimateur pour les paramètres d'un modèle de GARCH en moyenne (" GARCH-M ") avec plusieurs variables. L'estimateur a l'efficacité semiparamétrique quand les erreurs suivent une loi de probabilité qui est elliptiquement symétrique mais n'aucune autre restriction. Sous les hypothèses de haut niveau, notre estimateur obtient la limite d'efficacité semiparamétrique. L'hypothèse de la symétrie elliptique nous permet d'éviter le problème d'estimer non-paramétriquement une fonction de haut dimension, parce qu'on peut écrire la densité d'un loi elliptique comme un fonction d'une transformation unidimensionnelle de la variable aléatoire multidimensionnelle. Ce cadre est approprié pour analyser des modèles conditionnels des prix des actifs financiers, comme le CAPM conditionnel. Nous appliquons notre méthodologie à l'étude des prix des actions, et nous rendons compte des résultats d'une étude simulation "Monte-Carlo".Capital asset pricing model, elliptical symmetry, semiparametric efficiency, GARCH.
Circular 12
Ih Alaska—
Oats-and-peas make better silage than hay /
Silage and silos pay /
Field-choppers cut labor costs /
Smooth bromegrass is an excellent forage /
Alsike clover and Hubam sweetclover /
make good annuals /
Better forage means bigger profitsIn cooperation with the United States Department of Agriculture, Agricultural Research Administratio
An economic analysis of trading on private information by external administrators: international comparisons
This paper examines the regulation of trades in listed securities by external administrators (EAs), such as trustees in bankruptcy, liquidators, receivers, and administrators on the basis of private information. We consider the economic policy issues associated with such trades. The principal considerations counsel in favour of taking a permissive approach. These are: the difficulties of associating trades with insider information, given the EA's necessarily short expected holding period, the asymmetric application of the insider trading prohibition to sales (rather than decisions not to sell), the market incentives not to misuse private information that apply to EAs, and the unlikelihood that the EA has monopolistic access to the information in question. We consider these considerations by reference to a number of hypothetical scenarios. The paper argues that the law should regulate the subject by coupling a broad exemption for EAs with a "goiod faith" proviso, a continuous disclosure obligation, and a requirement to sell "all or nothing" of a holding of listed securities
Giving subjects the eye and showing them the finger: socio-biological cues and saccade generation in the anti-saccade task.
Pointing with the eyes or the finger occurs frequently in social interaction to indicate
direction of attention and one's intentions. Research with a voluntary saccade task (where saccade
direction is instructed by the colour of a fixation point) suggested that gaze cues automatically
activate the oculomotor system, but non-biological cues, like arrows, do not. However, other work
has failed to support the claim that gaze cues are special. In the current research we introduced
biological and non-biological cues into the anti-saccade task, using a range of stimulus onset
asynchronies (SOAs). The anti-saccade task recruits both top ^ down and bottom^ up attentional
mechanisms, as occurs in naturalistic saccadic behaviour. In experiment 1 gaze, but not arrows,
facilitated saccadic reaction times (SRTs) in the opposite direction to the cues over all SOAs,
whereas in experiment 2 directional word cues had no effect on saccades. In experiment 3 finger
pointing cues caused reduced SRTs in the opposite direction to the cues at short SOAs. These
findings suggest that biological cues automatically recruit the oculomotor system whereas non-
biological cues do not. Furthermore, the anti-saccade task set appears to facilitate saccadic responses in the opposite direction to the cues
Evidence of late Quaternary environmental change in a continental east Antarctic lake from lacustrine sedimentary pigment distributions
A sediment core from Progress Lake, one of the oldest lacustrine sequences in East Antarctica, contains distinct zones dating from a previous interglacial (most likely Marine Isotope Stage 5e, c. 125-115 kyr BP) and the present interglacial (Marine Isotope Stage 1), separated by a transition zone representing when the lake became sub-glacial. Profiles of fossil pigments, determined using high performance liquid chromatography and liquid chromatography-tandem mass spectrometry, show distinct differences in the photoautotrophic community during these two interglacial periods. The first was dominated by algae and purple phototrophic bacteria, with periods of photic zone euxinia indicated by pigments from anoxygenic phototrophic bacteria. Specific chlorophyll a derivatives reveal periods when grazing pressure impacted significantly on the phytoplankton community. The virtual absence of pigments in the transition zone reflects severe restriction of photoautotrophic activity, consistent with the take having become sub-glacial. Retreat of snow and ice in the late Holocene (3345 C-14 yr Bp) allowed establishment of a less diverse primary producer community, restricted to algae and cyanobacteria. Grazers were severely restricted and oxidative transformation was more important than during the previous interglacial. The pigment data provide a unique and detailed insight in to the evolution of the lake ecology over an interglacial-glacial-interglacial transition and strong evidence that the Marine Isotope Stage 5e interglacial in this region of coastal East Antarctica was several degrees warmer than at present
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