The exact power envelope of tests for a unit root

We show how to obtain the exact power envelope of tests for a unit root against trend-stationary alternatives, under normality. This is in contrast to the asymptotic power envelope derived by Elliott, Rothenberg and Stock (1996), and is used to indicate the lack of power of unit root tests in fixed sample sizes. <br><br> Keywords; power envelope, unit root tests <br><br> JEL classification: C12, C22

Contemplative Practices: A Strategy to Improve Health and Reduce Disparities.

Health has many dimensions, and intolerance and lack of compassion may contribute to the poor health and disparities in our nation. Tolerance can convey an inherent paradox or dissonance that can be associated with stress. However, tolerance has a dimension of acceptance, an acknowledgement and acceptance of what "is" at the present moment, that can relieve tension associated with differing beliefs and practices. Compassionate consideration of others can be combined with acceptance to create harmony within and across individuals. In this article, we explore how contemplative practices can cultivate tolerance and compassion and contribute to improvements in individual and population health

Estimation of fiber diameters in the spinal dorsal columns from clinical data

Lack of human morphometric data regarding the largest nerve fibers in the dorsal columns (DCs) of the spinal cord has lead to the estimation of the diameters of these fibers from clinical data retrieved from patients with a new spinal cord stimulation (SCS) system. These patients indicated the perception threshold of stimulation induced paresthesia in various body segments, while the stimulation amplitude was increased. The fiber diameters were calculated with a computer model, developed to calculate the effects of SCS on spinal nerve fibers. This computer model consists of two parts: (1) a three-dimensional (3-D) volume conductor model of a spinal cord segment in which the potential distribution due to electrical stimulation is calculated and (2) an electrical equivalent cable model of myelinated nerve fiber, which uses the calculated potential field to determine the threshold stimulus needed for activation. It is shown that the largest fibers in the medial DCs are significantly smaller than the largest fibers in the lateral parts. This finding is in accordance with the fiber distribution in cat, derived from the corresponding propagation velocities. Moreover, it is shown that the mediolateral increase in fiber diameter is mainly confined to the lateral parts of the DCs. Implementation of this mediolateral fiber diameter distribution of the DCs in the computer model enables the prediction of the recruitment order of dermatomal paresthesias following increasing electrical stimulation amplitud

Notes on three raptor species new to Flores

Details are given of sightings of Bonelli's Eagle Hieraaetus fasciatus. Rufous-bellied Eagle H. kienerii and a Honey-Buzzard Pernis sp. on Flores, extending the known range of these specie

Disulphide production by Ero1alpha-PDI relay is rapid and effectively regulated

The molecular networks that control endoplasmic reticulum (ER) redox conditions in mammalian cells are incompletely understood. Here, we show that after reductive challenge the ER steady-state disulphide content is restored on a time scale of seconds. Both the oxidase Ero1alpha and the oxidoreductase protein disulphide isomerase (PDI) strongly contribute to the rapid recovery kinetics, but experiments in ERO1-deficient cells indicate the existence of parallel pathways for disulphide generation. We find PDI to be the main substrate of Ero1alpha, and mixed-disulphide complexes of Ero1 primarily form with PDI, to a lesser extent with the PDI-family members ERp57 and ERp72, but are not detectable with another homologue TMX3. We also show for the first time that the oxidation level of PDIs and glutathione is precisely regulated. Apparently, this is achieved neither through ER import of thiols nor by transport of disulphides to the Golgi apparatus. Instead, our data suggest that a dynamic equilibrium between Ero1- and glutathione disulphide-mediated oxidation of PDIs constitutes an important element of ER redox homeostasis

The impact of within-herd genetic variation upon inferred transmission trees for foot-and-mouth disease virus

Full-genome sequences have been used to monitor the fine-scale dynamics of epidemics caused by RNA viruses. However, the ability of this approach to confidently reconstruct transmission trees is limited by the knowledge of the genetic diversity of viruses that exist within different epidemiological units. In order to address this question, this study investigated the variability of 45 foot-and-mouth disease virus (FMDV) genome sequences (from 33 animals) that were collected during 2007 from eight premises (10 different herds) in the United Kingdom. Bayesian and statistical parsimony analysis demonstrated that these sequences exhibited clustering which was consistent with a transmission scenario describing herd-to-herd spread of the virus. As an alternative to analysing all of the available samples in future epidemics, the impact of randomly selecting one sequence from each of these herds was used to assess cost-effective methods that might be used to infer transmission trees during FMD outbreaks. Using these approaches, 85% and 91% of the resulting topologies were either identical or differed by only one edge from a reference tree comprising all of the sequences generated within the outbreak. The sequence distances that accrued during sequential transmission events between epidemiological units was estimated to be 4.6 nucleotides, although the genetic variability between viruses recovered from chronic carrier animals was higher than between viruses from animals with acute-stage infection: an observation which poses challenges for the use of simple approaches to infer transmission trees. This study helps to develop strategies for sampling during FMD outbreaks, and provides data that will guide the development of further models to support control policies in the event of virus incursions into FMD free countries

Recent rift formation and impact on the structural integrity of the Brunt Ice Shelf, East Antarctica

We report on the recent reactivation of a large rift in the Brunt Ice Shelf, East Antarctica, in December 2012 and the formation of a 50 km long new rift in October 2016. Observations from a suite of ground-based and remote sensing instruments between January 2000 and July 2017 were used to track progress of both rifts in unprecedented detail. Results reveal a steady accelerating trend in their width, in combination with alternating episodes of fast ( > 600 m day−1) and slow propagation of the rift tip, controlled by the heterogeneous structure of the ice shelf. A numerical ice flow model and a simple propagation algorithm based on the stress distribution in the ice shelf were successfully used to hindcast the observed trajectories and to simulate future rift progression under different assumptions. Results show a high likelihood of ice loss at the McDonald Ice Rumples, the only pinning point of the ice shelf. The nascent iceberg calving and associated reduction in pinning of the Brunt Ice Shelf may provide a uniquely monitored natural experiment of ice shelf variability and provoke a deeper understanding of similar processes elsewhere in Antarctica

Juggling competing activities: academic staff as doctoral candidates

This article explores the experiences of a group of established academic staff in New Zealand and the United Kingdom, as they undertake a doctorate in their home institutions. Our interest is in how individuals negotiate this dual status from a cultural historical activity theory (CHAT) stance which explores how rules, tools, community and divisions of labour, and interacting activity systems, shape doctoral experiences. The focus in this article, having analysed their detailed narrative accounts, is on how academics experience three interdependent activity systems: those surrounding the thesis, the institutional context, and the home-life spheres. Issues related to time, workload and supervision issues, variability in collegial support and impact on personal priorities and time emerged. There is a range of particularities – from easy access to resources/supervisors, to inflexible institutional regulations – applicable to this group of doctoral candidates. Negotiating life as an academic with concurrent doctoral candidature provides positive outcomes in terms of teaching, research confidence and general personal and professional development. However, a range of difficulties can also be encountered, particularly in relation to personal and professional relationships, and workload management