An international comparative study on the use of the Cohort Component Method for estimating national populations

This comparative study explores the use of the Cohort Component Method (CCM) to produce national level population estimates. This method is used annually to calculate mid-year population estimates for England and Wales by the Office for National Statistics (ONS). Initially the article considers recent population change in England and Wales, with particular emphasis on the growing importance and challenges faced by migration estimation. Comparisons are then made between how population estimates are produced in England and Wales and other countries, with a particular focus on differences in the way the CCM is applied. Recent changes in methods used to estimate population are then reviewed along with a discussion of alternative approaches such as those described in academic literature.     

The Importance of Being Timely

Policymakers want to know about real‐time economy performance. However, closely watched macroeconomic time series produced by national statistics offices are published infrequently, with a time lag and subject to revision. Such issues create uncertainty in tracking economic developments, a by‐product of which is to raise the value of business and consumer surveys. Although providing less granularity than official data series, the surveys are released in a timelier manner and are subject to little revision. Using real‐time data sourced from the Deutsche Bundesbank, the OECD and the Office for National Statistics, an assessment of the role that the popular and widely used Purchasing Managers' Index (PMI) play in reducing forecasting errors in a simple ‘nowcasting’ framework is undertaken. The empirical exercise is conducted for five developed economies and also covers the period of the Great Recession. The conclusion is clear: timing matters. Copyright © 2015 John Wiley & Sons, Ltd.     

New records of rare deep-water fish species in the Eastern Ionian Sea (Mediterranean Sea)

We report new species records and information related to meristic, morphometric, bathymetric and biological characteristics that increase our knowledge of the deep ichthyofauna of the Ionian Sea (E. Mediterranean). The material was collected with long lines from 300 to 800 m deep in the Eastern Ionian Sea in June and October 2010. The fish species Schedophilus ovalis (Cuvier, 1833) (Osteichthyes: Centrolophidae), Sudis hyalina Rafinesque, 1810 (Osteicthyes: Paralepididae), Brama brama (Bonnaterre, 1788) (Osteichthyes: Bramidae) and Trachipterus trachypterus (Gmelin, 1789) (Osteichthyes: Trachipteridae) were recorded for the first time in the Eastern Ionian Sea. The absence of these new or rare species from the ichthyofauna of the study area to date is probably related to the absence of adequate sampling and catching techniques, although environmental factors could also be involved.     

Proximity signal and shade avoidance differences between early and late successional trees.

Competitive interactions between plants determine the success of individuals and species. In developing forests, competition for light is the predominant factor. Shade tolerators acclimate photosynthetically to low light and are capable of long-term survival under the shade cast by others, whereas shade avoiders rapidly dominate gaps but are overtaken in due course by shade-tolerant, later successional species. Shade avoidance results from the phytochrome-mediated perception of far-red radiation (700-800 nm) scattered from the leaves of neighbours, provides early warning of shading, and induces developmental responses that, when successful, result in the overgrowth of those neighbours. Shade tolerators cast a deep shade, whereas less-tolerant species cast light shade, and saplings tend to have high survivorship in shade cast by conspecific adults, but high rates of mortality when shaded by more-tolerant species. Here we report a parallel relationship in which the shade-avoidance responses of three tree species are inversely proportional to proximity signals generated by those species. On this basis, early successional species generate small proximity signals but react strongly to them, whereas late successional species react weakly but generate strong signals.     

Constructing Ultrametric and Additive Trees Based on the L 1 Norm

L ₁) criterion. Examples of ultrametric and additive trees fitted to two extant data sets are given, plus a Monte Carlo analysis to assess the impact of both typical data error and extreme values on fitted trees. Solutions are compared to the least-squares (L ₂) approach of Hubert and Arabie (1995a), with results indicating that (with these data) the L ₁ and L ₂ optimization strategies perform very similarly. A number of observations are made concerning possible uses of an L ₁ approach, the nature and number of identified locally optimal solutions, and metric recovery differences between ultrametrics and additive trees.     

High interannual variability of sea ice thickness in the Arctic region

Possible future changes in Arctic sea ice cover and thickness, and consequent changes in the ice-albedo feedback, represent one of the largest uncertainties in the prediction of future temperature rise. Knowledge of the natural variability of sea ice thickness is therefore critical for its representation in global climate models. Numerical simulations suggest that Arctic ice thickness varies primarily on decadal timescales owing to changes in wind and ocean stresses on the ice, but observations have been unable to provide a synoptic view of sea ice thickness, which is required to validate the model results. Here we use an eight-year time-series of Arctic ice thickness, derived from satellite altimeter measurements of ice freeboard, to determine the mean thickness field and its variability from 65 degrees N to 81.5 degrees N. Our data reveal a high-frequency interannual variability in mean Arctic ice thickness that is dominated by changes in the amount of summer melt, rather than by changes in circulation. Our results suggest that a continued increase in melt season length would lead to further thinning of Arctic sea ice.     

澳大利亚新英格兰地区桉树林的群落结构特征

本文研究澳大利亚新英格兰地区开阔林的群落结构特征。结果表明其种类组成较为简单,调查的4.8公顷样地中树木层只有18种。隶属于4属4科,树木个体90％为桉树;灌木层有32种19属13科;草本层有95种20属10科。群落的垂直结构为三层:树层,灌木层和草本层;一些林段只有二层(缺灌木层),或四层(增多小树层)。优势种群的分布格局多为集群分布。非优势种群的分布格局则多为随机分布格局。种间联结现象较弱,除少数种对外,联结系数低或没有联结。种间生态位的重叠值低,反映了诸多种群的独立分布特征。在其组织结构水平上,除草本层外。物种多样性指数、群落均匀度、生态优势度均较低。反映群落的优势种明显,为种多群落类型。     

Examining tensions in the past and present uses of concepts

Examining tensions between the past and present uses of scientific concepts can help clarify their contributions as tools in experimental practices. This point can be illustrated by considering the concepts of mental imagery and hallucinations: despite debates over their respective referential reliabilities remaining unresolved within their interdependent histories, both are used as independently stable concepts in neuroimaging experiments. Building on an account of how these concepts function as tools structured for pursuit of diverging goals in experiments, this paper explores this tension by re-examining the continued reliance of each concept on inverse characterisations inherited from the nominally-discarded ‘mediator-view’ of sensory-like mental phenomena (SLMP). In doing so, I seek to demonstrate how examining unresolved tensions can help highlight that entrenched associations can remain both integral to, and obscured by, the uses of concepts as goal-directed tools within experimental practices.