13,672 research outputs found
Microsimulation for demography
Background: Microsimulation consists of a set of techniques for estimating characteristics and modelling change in populations of individuals. Aims: To demonstrate how microsimulation can be used by demographers who want to undertake population estimates and projections. Data and methods: We use data from the 2011 United Kingdom (UK) Census of population to create a synthetic population by age, sex and ethnic group. Static and dynamic microsimulations and the visualisation of results are undertaken using the statistical package R. The code and data used in the static and dynamic microsimulation are available via a GitHub repository. Results: A synthetic population in 2011 by age, sex and ethnicity was produced for the East London Borough of Tower Hamlets, estimated from two Census tables. A population projection was produced for each of these age, sex and ethnicity groups to 2021. We used a projection of the Bangladeshi population to visualise population growth by Middle-layer Super Output Area (MSOA) and to produce a population pyramid of estimates in 2021. Conclusions: We argue that microsimulation is an adaptable technique which is well suited to demography, for both population estimation and projection. Although our example is applied to the East London Borough of Tower Hamlets, the approach could be readily applied in Australia, or any other country
The CCD and readout electronics for the OMC instrument on Integral
The Optical Monitoring Camera (OMC) on ESA's Integral gamma-ray astronomy satellite is devoted to optical wavelength observations simultaneously covering the same field-of-view as the gamma-ray and X-ray instruments. The OMC consists of a refracting telescope with a CCD as the imaging device in the focal plane. Here we describe the CCD and its associated readout electronics, in particular pointing out features of interest to users of the OMC instrument and its data
Demonstration of the Presence of the "Deleted" MIR122 Gene in HepG2 Cells
MicroRNA 122 (miR-122) is highly expressed in the liver where it influences diverse biological processes and pathways, including hepatitis C virus replication and metabolism of iron and cholesterol. It is processed from a long non-coding primary transcript (~7.5 kb) and the gene has two evolutionarily-conserved regions containing the pri-mir-122 promoter and pre-mir-122 hairpin region. Several groups reported that the widely-used hepatocytic cell line HepG2 had deficient expression of miR-122, previously ascribed to deletion of the pre-mir-122 stem-loop region. We aimed to characterise this deletion by direct sequencing of 6078 bp containing the pri-mir-122 promoter and pre-mir-122 stem-loop region in HepG2 and Huh-7, a control hepatocytic cell line reported to express miR-122, supported by sequence analysis of cloned genomic DNA. In contrast to previous findings, the entire sequence was present in both cell lines. Ten SNPs were heterozygous in HepG2 indicating that DNA was present in two copies. Three validation isolates of HepG2 were sequenced, showing identical genotype to the original in two, whereas the third was different. Investigation of promoter chromatin status by FAIRE showed that Huh-7 cells had 6.2 ± 0.19- and 2.7 ± 0.01- fold more accessible chromatin at the proximal (HNF4α-binding) and distal DR1 transcription factor sites, compared to HepG2 cells (p=0.03 and 0.001, respectively). This was substantiated by ENCODE genome annotations, which showed a DNAse I hypersensitive site in the pri-mir-122 promoter in Huh-7 that was absent in HepG2 cells. While the origin of the reported deletion is unclear, cell lines should be obtained from a reputable source and used at low passage number to avoid discrepant results. Deficiency of miR-122 expression in HepG2 cells may be related to a relative deficiency of accessible promoter chromatin in HepG2 versus Huh-7 cells
Acoustic transmission through compound subwavelength slit arrays
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.The angular dependence of the transmission of sound in air through four types of 2D slit-arrays
formed of aluminium slats is explored, both experimentally and numerically. For a simple, subwavelength
periodic slit-array, it is well known that Fabry-Perot-like wave-guide resonances, supported
by the slit-cavities, hybridising with bound acoustic surface waves, result in ‘Enhanced Acoustic
Transmission’ at frequencies determined by the length, width and separation of each slit-cavity. We
demonstrate that altering the spacing or width of some of the slits to form a compound array (i.e.
an array having a basis comprised of more than one slit) results in sharp dips in the transmission
spectra, that may have a strong angular dependence. These features correspond to ‘phase resonances’,
which have been studied extensively in the electromagnetic case. This geometry allows for
additional near-field configurations compared to the simple array, whereby the field in adjacent cavities
can be out-of-phase. Several types of compound slit-array are investigated; one such structure
is optimised to minimise the effect of boundary-layer loss mechanisms present in each slit cavity,
thereby achieving a deep, sharp transmission minimum in a broad maximumThe authors would like to thank the UK Ministry of Defence’s
Defence Science and Technology Laboratorty (DSTL)
for their financial support and permission to publis
The waveguiding of sound using lines of resonant holes
This is the final version. Available on open access from Nature Research via the DOI in this recordThe dispersion of an acoustic surface wave supported by a line of regularly spaced, open
ended holes in an acrylic plate, is characterised by precise measurement of its localised acoustic
fields. We illustrate the robust character of this surface wave and show its potential for control of
sound by the acoustic waveguiding provided by a ring of regularly spaced holes.Defence Science and Technology Laboratory (DSTL
Lipidomic profiling in Crohn's disease: abnormalities in phosphatidylinositols, with preservation of ceramide, phosphatidylcholine and phosphatidylserine composition.
Crohn's disease is a chronic inflammatory condition largely affecting the terminal ileum and large bowel. A contributing cause is the failure of an adequate acute inflammatory response as a result of impaired secretion of pro-inflammatory cytokines by macrophages. This defective secretion arises from aberrant vesicle trafficking, misdirecting the cytokines to lysosomal degradation. Aberrant intestinal permeability is also well-established in Crohn's disease. Both the disordered vesicle trafficking and increased bowel permeability could result from abnormal lipid composition. We thus measured the sphingo- and phospholipid composition of macrophages, using mass spectrometry and stable isotope labelling approaches. Stimulation of macrophages with heat-killed Escherichia coli resulted in three main changes; a significant reduction in the amount of individual ceramide species, an altered composition of phosphatidylcholine, and an increased rate of phosphatidylcholine synthesis in macrophages. These changes were observed in macrophages from both healthy control individuals and patients with Crohn's disease. The only difference detected between control and Crohn's disease macrophages was a reduced proportion of newly-synthesised phosphatidylinositol 16:0/18:1 over a defined time period. Shotgun lipidomics analysis of macroscopically non-inflamed ileal biopsies showed a significant decrease in this same lipid species with overall preservation of sphingolipid, phospholipid and cholesterol composition
Leishmania-specific surface antigens show sub-genus sequence variation and immune recognition.
A family of hydrophilic acylated surface (HASP) proteins, containing extensive and variant amino acid repeats, is expressed at the plasma membrane in infective extracellular (metacyclic) and intracellular (amastigote) stages of Old World Leishmania species. While HASPs are antigenic in the host and can induce protective immune responses, the biological functions of these Leishmania-specific proteins remain unresolved. Previous genome analysis has suggested that parasites of the sub-genus Leishmania (Viannia) have lost HASP genes from their genomes
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“But How Do We Get to the Greenway?”— A Multi-disciplinary, Multi-jurisdiction, Multimodal Strategy to Increase Connections to the Charles River Basin
The world-famous Charles River Reservation lines both sides of its majestic river for 8-1/2 miles in greater Boston. Created as a State Reservation between 1910 and 1936, this beautiful urban greenway contains continuous, longitudinal paths that serve as “trunk routes” for non-motorized transportation, hourly serving as many as 10,000 cyclists, pedestrians and runners. However, narrow bridges and urban land uses abutting the Reservation (high-volume arterial roads, railyards and car-oriented streets and businesses) present major barriers to access from the adjacent communities and to the greenway and the river.
This paper presents the draft findings and specific strategies of a “Pedestrian and Bicyclist Connectivity Study.” It was commissioned jointly by two state agencies—(a) the Massachusetts Department of Transportation, which has primary jurisdiction over the Charles River roads and bridges in the study area; and (b) the Massachusetts Department of Conservation and Recreation, responsible for care and control of the Charles River Reservation.
The Study was prepared between 2009 and 2013 by a team led by the Boston landscape architecture firm of Halvorson Design Partnership, with Alta Planning + Design, multi-modal planners and HDR Engineering, civil engineers.
The research design involved a rigorous, data-driven methodology that analyzed existing “bikeped” infrastructure and trip generators. The study also assessed the nature and location of barriers to access in and around the Reservation, and the ten bridges that traverse it.
A “toolbox” of 22 specific measures with potential to improve connectivity for the Charles River Reservation was developed.
The overall goal of this project is to improve the quality of life for tens of thousands of people who live or work within walking, running, skating or bicycling distance by increasing use of the greenway as a transportation and recreational resource. Accordingly, more than 100 specific improvements in the approaches to (and river crossings within) the greenway were identified to enhance pedestrian and bicycle connectivity to the adjacent neighborhoods, many of which currently have limited or missing connections to the river. (See Figure 1.)
Changes in the Charles River Basin area do not occur in isolation: roadway projects, new trails and greenways, and renovated bridges are being implemented throughout the region. Nonmotorized mobility initiatives, programs and policies are already encouraging a more diverse mix of travel patterns and behaviors, helping the region to move towards a “mode shift” away from private automobiles to more sustainable modes.
[This is happening in Cambridge and Boston already, as each city continues to improve the walking environment, promote universal accessibility and develop a network of integrated bicycle facilities. A notable example of this phenomenon is the implementation in Boston of “Hubway,” a city-wide bicycle sharing system, sponsored by New Balance and operated by Alta Bike Share. In its first 16 months of operation, Hubway recorded more than 675,000 separate trips. 2012 saw the expansion of the system to neighboring Cambridge and Somerville and plans are underway to add Hubway stations and bikes to Brookline, as well. All four municipalities are working with Massachusetts Department of Transportation, Metropolitan Area Planning Council, Massachusetts Bay Transportation Authority and the Federal Transit Administration to continue to fill and expand the system in the Metro Area.
Caffeine Consumption and General Health in Secondary School Children: A Cross-sectional and Longitudinal Analysis
Although caffeine is sometimes associated with beneficial effects in adults, the substance may be dangerous if intake is too high. This concern is particularly relevant in regards to children and adolescents, as consumption of energy drinks may be particularly high in such populations. For this reason, the current study examined data from the Cornish Academies Project to determine whether caffeine intake in secondary school children was related to responses to a single-item measure of general health. Two cross-sections of data were available: questionnaires were completed by 2030 at baseline, by 2307 at 6-month follow-up, and by 1660 at both time-points. Relationships were, therefore, explored both cross-sectionally and longitudinally. High caffeine consumption (i.e., 1000 mg/week) was associated with low general health in both cross-sections of data, and analyses of individual caffeine sources suggested that the effects related specifically to cola and energy drinks. However, after controlling for additional aspects of diet, demography, and lifestyle, total weekly intake only remained significantly associated with general health at the latter time-point. Further to this, null findings from cross-lag and change-score analyses suggest that caffeine and general health were unlikely to be causally linked in this sample. However, due to methodological limitations, such as the two cross-sections of data being collected only 6 months apart, it is suggested that further longitudinal and intervention studies are required in order for firm conclusions to be drawn.This work was supported by The Waterloo Foundation (grant number 503692)
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