LEF2 - A strategic freight transport model for Great Britain.

INTRODUCTION This paper reports some innovative model building that yields a useful addition to models of freight in Great Britain. Currently, the Great Britain Freight Model (GBFM) is part of the Department for Transport's (DtT) national model suite. That model is over-detailed for some purposes and internally only models mode choice effects. Freight modelling requirements in Great Britain were reviewed in work for the DtT, the Strategic Rail Authority (SRA), the Highways Agency (HA) and Transport for London (TfL). Arising from our work on that project, and our involvement with GBFM, we identified a need for a strategic freight transport model, near instantaneous to run, that could handle both the mode choice effects and market size effects of policies. Section 2 of this paper sets out the background to our work. Section 3 introduces the LEeds Freight Transport (LEFT) model series. Section 4 describes the model LEFT2 from that series, and section 5 gives some results using version LEFT2.6. Section 6 lists the plans we currently have for LEFT3, and section 7 concludes

The Development of the LEFT2 Model

Construction of the LEeds Freight Transport Model (LEFT) series was begun as part of the ITeLS project, although other funding has helped and will take forward its development. The initial version, now referred to by us as LEFT1, was a simple mode split model intended to give a rough idea of the magnitudes of the effects of various scenarios, possibly as a way of filtering which scenarios might be investigated using more detailed models. Besides being limited to mode split, LEFT1 suffered from a range of minor defects and deficiencies which led to its abandonment in favour of its successor, LEFT2. LEFT2 was constructed in 2004 as part of the Engineering and Physical Sciences Research Council LINK FIT project, ITeLS, funded by the Department for Transport (DfT). We acknowledge here the help and useful comments from many persons associated with that project. Besides mode split effects, LEFT2 allows scenarios to alter the total size of the (road plus rail) market. Its purpose is to provide instantaneous ballpark estimates of road and rail freight tonne kilometres under various ‘scenarios’. At its base is a desire that the scenarios should not affect the sum of tonnes moved by both road and rail modes. This was because we felt that our scenarios should be viewed as having a neutral macroeconomic effect. For example, if taxes on lorry usage were increased, we would expect other taxes to be lower than otherwise (or government spending to increase) so that total demand in the economy would not change. Consumers might buy their goods from closer sources than hitherto, but they would not be expected to consume less in total. For example, if prices of some goods rose slightly due to higher road user charges, the consumer would have more to spend due to offsetting reduced income tax (or whatever) and much the same total quantity would be bought. Similarly, industrialists as a whole might find input prices increasing slightly, but will find they can charge slightly more for their outputs. In summary, LEFT2 provides an instantaneous estimate of the effect of macroeconomically neutral scenarios on mode split (road, trainload and wagonload), average length of haul and total market size. LEFT2 does not load the traffic onto vehicles, and so does not produce magnitudes of HGV vehicle kilometres, for instance. Consequently it does not produce estimates of emissions or other nuisances. It is hoped that a future version of LEFT can incorporate these elements and revisit the other matters that have had to be ‘parked’ for the present. LEFT2 gives a quick idea of the magnitudes of the effects of any policies that might be considered and should help to provide a first sift where many policies are being considered. This report describes the basic LEFT Methodology in Section 2. Emphasis is given to that methodology actually embodied in LEFT2, but there is also some discussion of rejected 4 methodologies, and some that have had to be held over for later versions of LEFT. Section 3 presents additional data that was needed by the LEFT2 model. Section 4 describes the scenarios chosen for testing in the ITeLS project, while section 5 gives the first results from using the LEFT2 model, for those scenarios

Paired and altruistic kidney donation in the UK: algorithms and experimentation

We study the computational problem of identifying optimal sets of kidney exchanges in the UK. We show how to expand an integer programming-based formulation [1, 19] in order to model the criteria that constitute the UK definition of optimality. The software arising from this work has been used by the National Health Service Blood and Transplant to find optimal sets of kidney exchanges for their National Living Donor Kidney Sharing Schemes since July 2008.We report on the characteristics of the solutions that have been obtained in matching runs of the scheme since this time. We then present empirical results arising from the real datasets that stem from these matching runs, with the aim of establishing the extent to which the particular optimality criteria that are present in the UK influence the structure of the solutions that are ultimately computed. A key observation is that allowing 4-way exchanges would be likely to lead to a significant number of additional transplants

Mid-Miocene cooling and the extinction of tundra in continental Antarctica

A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40Ar/39Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ± 0.05 Ma and 13.85 ± 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition

Learning and Matching Multi-View Descriptors for Registration of Point Clouds

Critical to the registration of point clouds is the establishment of a set of accurate correspondences between points in 3D space. The correspondence problem is generally addressed by the design of discriminative 3D local descriptors on the one hand, and the development of robust matching strategies on the other hand. In this work, we first propose a multi-view local descriptor, which is learned from the images of multiple views, for the description of 3D keypoints. Then, we develop a robust matching approach, aiming at rejecting outlier matches based on the efficient inference via belief propagation on the defined graphical model. We have demonstrated the boost of our approaches to registration on the public scanning and multi-view stereo datasets. The superior performance has been verified by the intensive comparisons against a variety of descriptors and matching methods

Use of variability in national and regional data to estimate the prevalence of lymphangioleiomyomatosis

Background: Understanding the true prevalence of lymphangioleiomyomatosis (LAM) is important in estimating disease burden and targeting specific interventions. As with all rare diseases, obtaining reliable epidemiological data is difficult and requires innovative approaches. Aim: To determine the prevalence and incidence of LAM using data from patient organizations in seven countries, and to use the extent to which the prevalence of LAM varies regionally and nationally to determine whether prevalence estimates are related to health-care provision. Methods: Numbers of women with LAM were obtained from patient groups and national databases from seven countries (n = 1001). Prevalence was calculated for regions within countries using female population figures from census data. Incidence estimates were calculated for the USA, UK and Switzerland. Regional variation in prevalence and changes in incidence over time were analysed using Poisson regression and linear regression. Results: Prevalence of LAM in the seven countries ranged from 3.4 to 7.8/million women with significant variation, both between countries and between states in the USA. This variation did not relate to the number of pulmonary specialists in the region nor the percentage of population with health insurance, but suggests a large number of patients remain undiagnosed. The incidence of LAM from 2004 to 2008 ranged from 0.23 to 0.31/million women/per year in the USA, UK and Switzerland. Conclusions: Using this method, we have found that the prevalence of LAM is higher than that previously recorded and that many patients with LAM are undiagnose

Variable Hard-X-Ray Emission from the Candidate Accreting Black Hole in Dwarf Galaxy Henize 2-10

We present an analysis of the X-ray spectrum and long-term variability of the nearby dwarf starburst galaxy Henize 2–10. Recent observations suggest that this galaxy hosts an actively accreting black hole (BH) with mass ~106 ${{M}_{\odot }}$. The presence of an active galactic nucleus (AGN) in a low-mass starburst galaxy marks a new environment for AGNs, with implications for the processes by which "seed" BHs may form in the early universe. In this paper, we analyze four epochs of X-ray observations of Henize 2–10, to characterize the long-term behavior of its hard nuclear emission. We analyze observations with Chandra from 2001 and XMM-Newton from 2004 and 2011, as well as an earlier, less sensitive observation with ASCA from 1997. Based on a detailed analysis of the source and background, we find that the hard (2–10 keV) flux of the putative AGN has decreased by approximately an order of magnitude between the 2001 Chandra observation and exposures with XMM-Newton in 2004 and 2011. The observed variability confirms that the emission is due to a single source. It is unlikely that the variable flux is due to a supernova or ultraluminous X-ray source, based on the observed long-term behavior of the X-ray and radio emission, while the observed X-ray variability is consistent with the behavior of well-studied AGNs

Optical properties of a two-dimensional electron gas at even-denominator filling fractions

The optical properties of an electron gas in a magnetic field at filling fractions \nu = {1\over 2m} (m=1,2,3...) are investigated using the composite fermion picture. The response of the system to the presence of valence-band holes is calculated. The shapes of the emission spectra are found to differ qualitatively from the well-known electron-hole results at zero magnetic field. In particular, the asymmetry of the emission lineshape is found to be sensitive to the hole-composite fermion plane separation.Comment: 17 pages, LaTeX, 7 figures. This revised version is to appear in Physical Review

Relationship of food insecurity to women's dietary outcomes: a systematic review

Context: Food insecurity matters for women's nutrition and health. Objective: This review sought to comprehensively evaluate how food insecurity relates to a full range of dietary outcomes (food groups, total energy, macronutrients, micronutrients, and overall dietary quality) among adult women living in Canada and the United States. Data sources: Peer-reviewed databases (PubMed/MEDLINE, CINAHL, Scopus, Web of Science) and gray literature sources from 1995 to 2016 were searched. Data extraction: Observational studies were used to calculate a percentage difference in dietary intake for food-insecure and food-secure groups. Results: Of the 24 included studies, the majority found food-insecure women had lower food group frequencies (dairy, total fruits and vegetables, total grains, and meats/meat alternatives) and intakes of macro- and micronutrients relative to food-secure women. Methodological quality varied. Among high-quality studies, food insecurity was negatively associated with dairy, fruits and vegetables, grains, meats/meats alternatives, protein, total fat, calcium, iron, magnesium, vitamins A and C, and folate. Conclusions: Results hold practical relevance for selecting nutritional targets in programs, particularly for nutrient-rich foods with iron and folate, which are more important for women's health