llc: a collection of R functions for fitting a class of Lee-Carter mortality models using iterative fitting algorithms

We implement a specialised iterative regression methodology in R for the analysis of age-period mortality data based on a class of generalised Lee-Carter (LC) type modelling structures. The LC-based modelling frameworks is viewed in the current literature as among the most efficient and transparent methods of modelling and projecting mortality improvements. Thus, we make use of the modelling approach discussed in Renshaw and Haberman (2006), which extends the basic LC model and proposes to make use of a tailored iterative process to generate parameter estimates based on Poisson likelihood. Furthermore, building on this methodology we develop and implement a stratified LC model for the measurement of the additive effect on the log scale of an explanatory factor (other than age and time). This modelling methodology is implemented in a publically available collection of programming functions that facilitate both the preparation of mortality data and the fitting and analysis of the given log-linear modelling structures. Also, the package incorporates methods to produce forecasts of future mortality rates and to compute the corresponding future life expectancy

A comparative study of parametric mortality projection models

The relative merits of different parametric models for making life expectancy and annuity value predictions at both pensioner and adult ages are investigated. This study builds on current published research and considers recent model enhancements and the extent to which these enhancements address the deficiencies that have been identified of some of the models. The England & Wales male mortality experience is used to conduct detailed comparisons at pensioner ages, having first established a common basis for comparison across all models. The model comparison is then extended to include the England & Wales female experience and both the male and female USA mortality experiences over a wider age range, encompassing also the working ages

Gender Gaps in the Measurement of Public Opinion About Homosexuality in Cross-national Surveys: A Question-Wording Experiment

Measures of attitudes towards homosexuality in cross-national studies have received criticism for not being ‘gender-sensitive’. The current study used a split-ballot design allowing for separate analyses of the attitudes towards ‘gay men and lesbian women’, ‘gay men’, and ‘lesbian women’ in a pooled sample of 3,381 participants from Great Britain, Hungary, and Portugal. Analyses controlling for sociodemographics showed that differences in attitudes towards male and female targets were generally small and did not interact with the gender of the rater. In addition, results showed that men’s attitudes towards homosexuality were more strongly related to their gender ideology than women’s attitudes. Implications of these findings for cross-national studies measuring attitudes towards homosexuality are discussed

Contemporary Issues in Current Account Operations in Pakistani IBs - Sharia Compliant Solution

Contemporary Sharia scholars have three stances about the Current Account Operations in Pakistani Islamic Banks (IBs) i.e., (i) Ijarah based contract (ii) Wadi'ah based contract, and (iii) Qard based contract. This paper is an attempt to delve into the root causes of the differences of scholars and to find the Sharia-compliant solution acceptable for all. Descriptive as well as applied approaches are used in this paper. Clearing of ambiguity on this issue may result in twofold benefits: from the public point of view, it would satisfy practising Muslims which may result in form of huge deposits in this account (ii) from IBs viewpoint the Current Account is a bonus deposit

MONETARY EXCHANGE RATE MODEL REVISITED: COINTEGRATION AND FORECASTING IN HETEROGENEOUS PANEL DATA

ABSTRACT This study re-examines the exchange rate-monetary fundamentals link with in a panel data framework. Pure time series and pooled time series-based tests fail to find empirical support for monetary exchange rate models (Sarantis (1994) and Groen (2000)). Using recently developed Panel Data Techniques; we would test the exchange rates and monetary fundamentals in a quarterly panel of 19 countries mostly from developed region extending from 1973.1 to 1997.1. Present analysis would be centered on three issues. First, we test whether exchange rates cointegrated with long run determinants predicted by economic theory. For this purpose, we would be employed Pedroni (1997) and Larsson et al (2001) panel cointegration tests for empirical validation of the study. Second, we will also test the short run implications of exchange rate model. These short run implications will be tested; through adapting the panel VEC model the short run identification schemes of Johansen and Juselius (1994). The last issue is to examine the ability for monetary fundamentals to forecast future exchange rate returns. The present endeavor will follow Mark and Sul (2001) approach for forecasting in the case of Panel Data Testing.Panel cointegration; Prediction; Exchange rates.

Parisian Mobility

A photograph of a red Vespa scooter in Paris, France. Shot on film on a Canon AE-1

Relative Odds of Neck Pain to Helmet Use Among Motorcyclists: a Case-Control Study

Background: Neck pain is a widespread problem among motorcyclists, which is often neglected. There is limited research on the motorcycle's ergonomics, particularly in the context of the interaction between the riders and motorcycle. Motorcycle helmets have proven to increase the weight on the neck, thus causing more burdens which can lead to neck pain. Methodology: Case-Control study design was opted to measure the relative odds of neck pain in relation to the helmet use as an exposure. A total of 260 (mean age of 22.58 ± S.D. 1.95 years) undergraduate students were selected using purposive sampling. The case to control ratio was 1:4 (54 Cases and 206 Controls) where cases were defined as the motorcyclists having neck pain with a riding experience of more than one year. The neck pain and disability scale were obtained using a self-administered questionnaire. Chi-square and binary logistic regression were used to calculate the significant relationship and odds of neck pain amongst motorcyclists with and without helmet use. Results: The study results showed that out of 260 motorcyclists, 190 (73.1%) were helmet users, and 54 (20.8%) had neck pain, 70 (27.9%) helmet users had a neck pain prevalence of 11 (4.2%). The relative odd to have neck pain was 2.13 times more amongst the motorcyclists using the helmet as compared to that of non-helmet users. The logistic regression results showed significant results (P < 0.05) with regards to the BMI, helmet weight and duration of helmet use but did not show a significant relation with average motorcycle use per day unless it exceeded 70 kilometres. Conclusion: Use of helmet can be a potential cause of neck pain amongst motorcyclist users but the odds to have neck pain enhance with the increase in motorcycle use per day. The protective benefits are multi-fold for helmet use which outreaches the negative impact, including neck pain amongst motorcyclists

Allometry and growth of eight tree taxa in United Kingdom woodlands.

This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0As part of a project to develop predictive ecosystem models of United Kingdom woodlands we have collated data from two United Kingdom woodlands - Wytham Woods and Alice Holt. Here we present data from 582 individual trees of eight taxa in the form of summary variables relating to the allometric relationships between trunk diameter, height, crown height, crown radius and trunk radial growth rate to the tree's light environment and diameter at breast height. In addition the raw data files containing the variables from which the summary data were obtained. Large sample sizes with longitudinal data spanning 22 years make these datasets useful for future studies concerned with the way trees change in size and shape over their life-span

Bond-forming and electron-transfer reactivity between Ar2+ and N2

Collisions between Ar2+ and N2 have been studied using a coincidence technique at a CM collision energy of 5.1 eV. Four reaction channels generating pairs of monocations are observed: Ar+ + N2+, Ar+ + N+, ArN+ + N+ and N+ + N+. The formation of Ar+ + N2+ is the most intense channel, displaying forward scattering but with a marked tail to higher scattering angles. This scattering, and other dynamics data, is indicative of direct electron transfer competing with a ‘sticky’ collision between the Ar2+ and N2 reactants. Here Ar+ is generated in its ground (2P) state and N2+ is primarily in the low vibrational levels of the C2Σu+ state. A minor channel involving the initial population of higher energy N2+ states, lying above the dissociation asymptote to N+ + N, which fluoresce to stable states of N2+ is also identified. The formation of Ar+ + N+ by dissociative single electron transfer again reveals the involvement the two different pathways for the initial electron transfer (direct or complexation). This reaction pathway predominantly involves excited states of Ar2+ (1D and 1S) populating N2+* in its dissociative C2Σu+, 22Πg and D2Πg states. Formation of ArN+ + N+ proceeds via a direct mechanism. The ArN+ is formed, with significant vibrational excitation, in its ground (X3Σ–) state. Formation of N+ + N+ is also observed as a consequence of double electron transfer. The exoergicity of the N22+ dissociation reveals the population of the A1Πu and D3Πg dication states