scholarly journals The evolution of built-up areas in Ghana since 1975

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0250847
Author(s):  
Marcel Fafchamps ◽  
Forhad Shilpi
Keyword(s):  
High Resolution ◽  
Sharp Increase ◽  
Transition Matrix ◽  
Arable Land ◽  
Strong Increase ◽  
Rural Settlements ◽  
Human Settlement ◽  
Agglomeration Effects ◽  
A Cell ◽  
Over Time

We use high resolution satellite data on the proportion of buildings in a 250x250 meter cell to study the evolution of human settlement in Ghana over a 40 year period. We find a strong increase in built-up area over time, mostly concentrated in the vicinity of roads, and also directly on the coast. We find strong evidence of agglomeration effects both in the static sense—buildup in one cell predicts buildup in a nearby cell—and in a dynamic sense—buildup in a cell predicts buildup in that cell later on and an increase in buildup in nearby cells. These effects are strongest over a 3 to 15 Km radius, which corresponds to a natural hinterland for a population without mechanized transportation. We find no evidence that human settlements are spaced more or less equally either over the landscape or along roads. This suggests that arable land is not yet fully utilized, allowing rural settlements to be separated by areas of un-farmed land. By fitting a transition matrix to the data, we predict a sharp increase in the proportion of the country that is densely built-up by the middle and the end of the century, but no increase in the proportion of partially built-up locations.

Analysis of Squalene and Its Transformation By-Products in Latent Fingermarks by Ultrahigh-Pressure Liquid Chromatography-High Resolution Accurate Mass Orbitrap™ Mass Spectrometry

2019 ◽  
Author(s):  
Buddhika Dorakumbura ◽  
Francesco Busetti ◽  
Simon Lewis
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
High Resolution ◽  
Storage Conditions ◽  
Ultrahigh Pressure ◽  
Accurate Mass ◽  
Rational Approach ◽  
By Products ◽  
Over Time ◽  
High Resolution Accurate Mass

<p>Transformation of squalene and its by-products in fingermarks over time under different storage conditions (light, dark and underwater) was examined through ultrahigh-pressure liquid chromatography high resolution accurate mass Orbitrap™ mass spectrometry. Complications of assessing fingermark compositional variation over time using multiple samples with varying initial compositions were elucidated and a more rational approach was successfully demonstrated. Squalene was detected in all fresh natural fingermarks and the amount ranged between 0.20 to 11.32 μg/5 fingertips. A notable difference in the transformation of squalene was observed with different storage conditions, where a dark aquatic environment accelerated degradation of squalene compared to dark but dry conditions. Squalene monohydroperoxide was extremely short-lived in natural deposits while the amount of squalene epoxide was still increasing relative to the initial amount, after ageing under dark and aquatic conditions for up to 7 days. Some oxidation by-products of cholesterol were also tentatively identified, which exhibited a growth over time against their initial concentration under any of the storage condition tested. These by-products, therefore, show potential as biomarkers for targeted visualisation of aged deposits.</p>

Changing Places: Rock Art and Holocene Landscapes in the Wadi al-Ajal, South-West Libya

2014 ◽  
Vol 12 (2) ◽  
pp. 165-182 ◽  
Author(s):  
Tertia Barnett ◽  
Maria Guagnin
Keyword(s):  
Spatial Analysis ◽  
Surface Water ◽  
Rock Art ◽  
Human Settlement ◽  
Gis Model ◽  
South West ◽  
Settlement Location ◽  
Central Sahara ◽  
The Relationship ◽  
Over Time

This article examines the relationship between rock art and landscape use by pastoral groups and early settled communities in the central Sahara from around 6000 BC to 1000 AD. During this period the region experienced significant climatic and environmental fluctuations. Using new results from a systematic survey in the Wadi al-Ajal, south-west Libya, our research combines data from over 2000 engraved rock art panels with local archaeological and palaeoenvironmental evidence within a GIS model. Spatial analysis of these data indicates a correspondence between the frequency of rock art sites and human settlement over time. However, while changes in settlement location were guided primarily by the constraints on accessibility imposed by surface water, the distribution of rock art relates to the availability of pasture and patterns of movement through the landscape. Although the reasons for these movements undoubtedly altered over time, natural routes that connected the Wadi al-Ajal and areas to the south continued to be a focus for carvings over several thousand years.

scholarly journals Visualising regional disparities in the risk of COVID-19 at different phases of lockdown in England

2021 ◽  
pp. 0308518X2098416
Author(s):  
Yu-Wang Chen ◽  
Lei Ni ◽  
Dong-Ling Xu ◽  
Jian-Bo Yang
Keyword(s):  
United Kingdom ◽  
Sharp Increase ◽  
Regional Disparities ◽  
Local Authorities ◽  
The North ◽  
Second Wave ◽  
Over Time

Since late January 2020 when the first coronavirus case reached England, United Kingdom, the coronavirus disease 2019 (COVID-19) has spread rapidly and widely across all local authorities (LAs) in England. In this featured graphic, we visualise how COVID-19 severity changes nationally and locally from 30 January to 23 November 2020. The geo-visualisation shows that there have been large regional disparities in the severity of the outbreak, and the epicentres have shifted from Greater London, Leicester, to the North of England and remained in the North during pre-lockdown, post-lockdown, easing lockdown and second national lockdown phases. We further find that the increase in the testing capacity may partially explain the sharp increase in the confirmed cases during the second wave of the pandemic. However, the disparities in the severity of COVID-19 (i.e., confirmed cases and deaths) among LAs in England become more significant over time. It further sheds light on the necessity of establishing decisive and timely responses to cope with local pandemic situations.

scholarly journals Reliability and Change in Erosion Measurements by High-Resolution peripheral Quantitative Computed Tomography in a Longitudinal Dataset of Rheumatoid Arthritis Patients

2020 ◽  
pp. jrheum.191391 ◽  
Author(s):  
Stephanie Finzel ◽  
Sarah L. Manske ◽  
Cheryl Barnabe ◽  
Andrew J. Burghardt ◽  
Hubert Marotte ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Computed Tomography ◽  
High Resolution ◽  
Intraclass Correlation ◽  
Quantitative Computed Tomography ◽  
Correlation Coefficients ◽  
Peripheral Quantitative Computed Tomography ◽  
Good Reliability ◽  
Change Over Time ◽  
Over Time

Objective The aim of this multi-reader exercise was to assess the reliability and change over time of erosion measurements in rheumatoid arthritis (RA) patients using high-resolution peripheral quantitative computed tomography (HR-pQCT). Methods HR-pQCT scans of 23 patients with RA were assessed at baseline and 12 months. Four experienced readers examined the dorsal, palmar, radial, and ulnar surfaces of the metacarpal head (MH) and phalangeal base (PB) of the 2nd and 3rd digits, blinded to time order. In total, 368 surfaces (23 patients x16 surfaces) were evaluated per time point to characterize cortical breaks as pathological (erosion) or physiological, and to quantify erosion width and depth. Reliability was evaluated by intraclass correlation coefficients (ICC), percentage agreement, and Light’s kappa; change over time was defined by means ± SD of erosion numbers and dimensions. Results ICCs for the mean measurements of width and depth of the pathological breaks ranged between 0.819 - 0.883, and 0.771 - 0.907 respectively. Most physiological cortical breaks were found at the palmar PB, whereas most pathological cortical breaks were located at the radial MH. There was a significant increase in both the numbers and the dimensions of erosions between baseline and follow-up (p=0.0001 for erosion numbers, width, and depth in axial plane, and p=0.001 for depth in perpendicular plane). Conclusion This exercise confirmed good reliability of HR-pQCT erosion measurements and their ability to detect change over time.

scholarly journals Order and stochasticity in the folding of individual Drosophila genomes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sergey V. Ulianov ◽  
Vlada V. Zakharova ◽  
Aleksandra A. Galitsyna ◽  
Pavel I. Kos ◽  
Kirill E. Polovnikov ◽  
...  
Keyword(s):  
Random Walk ◽  
High Resolution ◽  
3D Genome ◽  
Topologically Associating Domains ◽  
Chromatin Folding ◽  
A Cell ◽  
Single Nucleus ◽  
High Level ◽  
Cell To Cell Variability

AbstractMammalian and Drosophila genomes are partitioned into topologically associating domains (TADs). Although this partitioning has been reported to be functionally relevant, it is unclear whether TADs represent true physical units located at the same genomic positions in each cell nucleus or emerge as an average of numerous alternative chromatin folding patterns in a cell population. Here, we use a single-nucleus Hi-C technique to construct high-resolution Hi-C maps in individual Drosophila genomes. These maps demonstrate chromatin compartmentalization at the megabase scale and partitioning of the genome into non-hierarchical TADs at the scale of 100 kb, which closely resembles the TAD profile in the bulk in situ Hi-C data. Over 40% of TAD boundaries are conserved between individual nuclei and possess a high level of active epigenetic marks. Polymer simulations demonstrate that chromatin folding is best described by the random walk model within TADs and is most suitably approximated by a crumpled globule build of Gaussian blobs at longer distances. We observe prominent cell-to-cell variability in the long-range contacts between either active genome loci or between Polycomb-bound regions, suggesting an important contribution of stochastic processes to the formation of the Drosophila 3D genome.

scholarly journals Reproducibility of airway luminal size in asthma measured by HRCT

2017 ◽  
Vol 123 (4) ◽  
pp. 876-883 ◽  
Author(s):  
Robert H. Brown ◽  
Robert J. Henderson ◽  
Elizabeth A. Sugar ◽  
Janet T. Holbrook ◽  
Robert A. Wise
Keyword(s):  
High Resolution ◽  
Functional Residual Capacity ◽  
Total Lung Capacity ◽  
Ct Imaging ◽  
Disease State ◽  
Air Trapping ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Normal Variability ◽  
Over Time

Brown RH, Henderson RJ, Sugar EA, Holbrook JT, Wise RA, on behalf of the American Lung Association Airways Clinical Research Centers. Reproducibility of airway luminal size in asthma measured by HRCT. J Appl Physiol 123: 876–883, 2017. First published July 13, 2017; doi:10.1152/japplphysiol.00307.2017.—High-resolution CT (HRCT) is a well-established imaging technology used to measure lung and airway morphology in vivo. However, there is a surprising lack of studies examining HRCT reproducibility. The CPAP Trial was a multicenter, randomized, three-parallel-arm, sham-controlled 12-wk clinical trial to assess the use of a nocturnal continuous positive airway pressure (CPAP) device on airway reactivity to methacholine. The lack of a treatment effect of CPAP on clinical or HRCT measures provided an opportunity for the current analysis. We assessed the reproducibility of HRCT imaging over 12 wk. Intraclass correlation coefficients (ICCs) were calculated for individual airway segments, individual lung lobes, both lungs, and air trapping. The ICC [95% confidence interval (CI)] for airway luminal size at total lung capacity ranged from 0.95 (0.91, 0.97) to 0.47 (0.27, 0.69). The ICC (95% CI) for airway luminal size at functional residual capacity ranged from 0.91 (0.85, 0.95) to 0.32 (0.11, 0.65). The ICC measurements for airway distensibility index and wall thickness were lower, ranging from poor (0.08) to moderate (0.63) agreement. The ICC for air trapping at functional residual capacity was 0.89 (0.81, 0.94) and varied only modestly by lobe from 0.76 (0.61, 0.87) to 0.95 (0.92, 0.97). In stable well-controlled asthmatic subjects, it is possible to reproducibly image unstimulated airway luminal areas over time, by region, and by size at total lung capacity throughout the lungs. Therefore, any changes in luminal size on repeat CT imaging are more likely due to changes in disease state and less likely due to normal variability. NEW & NOTEWORTHY There is a surprising lack of studies examining the reproducibility of high-resolution CT in asthma. The current study examined reproducibility of airway measurements. In stable well-controlled asthmatic subjects, it is possible to reproducibly image airway luminal areas over time, by region, and by size at total lung capacity throughout the lungs. Therefore, any changes in luminal size on repeat CT imaging are more likely due to changes in disease state and less likely due to normal variability.

scholarly journals The Use of Multi-Sensor for Illegal Human Settlement Detection

2018 ◽  
Vol 3 (7) ◽  
pp. 171-178
Author(s):  
Arnis Asmat ◽  
Zamzami S.Z ◽  
Mansor S
Keyword(s):  
High Resolution ◽  
Open Access ◽  
Spectral Resolution ◽  
Publishing House ◽  
Spatial Filter ◽  
Human Settlement ◽  
Counting Approach ◽  
International Publishing ◽  
Spot 5 ◽  
Open Access Article

The paper presents preliminary results of legal and illegal settlement extraction in Pulau Gaya, Sabah using high resolution Quickbird and SPOT- 5 multi-spectral imageries using automated house detection technique. The technique developed is spatial-based using tree counting approach. From the results, edge to edge of the house features was found precisely separated and can be delineated between houses that less than 2m distance. Results show that the technique able to delineate legal houses from Quickbird image more than SPOT-5. Differs results would be due to different spatial and spectral resolution of images. Keywords: Quickbird, SPOT, spatial filter, tree counting eISSN 2514-751X © 2018. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open-access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.

scholarly journals Normal cycling patterns of hematopoietic stem cell subpopulations: an assay using long-term in vivo BrdU infusion

Blood ◽  
1985 ◽  
Vol 66 (6) ◽  
pp. 1460-1462 ◽  
Author(s):  
ME Pietrzyk ◽  
GV Priestley ◽  
NS Wolf
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Improved Method ◽  
Hematopoietic Stem ◽  
Infusion Study ◽  
A Cell ◽  
Cell Subpopulations ◽  
Over Time

It was found in a long-term bromodeoxyuridine (BrdU) infusion study that two or more different subpopulations of bone marrow stem cells exist in mice. One of these subpopulations appears to be noncycling and forms approximately 10% of eight-day CFU-S. Another one, a subpopulation of slowly cycling bone marrow cells, is represented as 14- day CFU-S. The 14-day CFU-S have a regular increment in the percentage of the subpopulation entering the cycle over time, with a cell generation half-time of 21 days. The cycling status in these experiments was ascertained by in vivo continuous long-term BrdU infusion. An improved method is presented for long-term BrdU infusion with UV killing of cycled cells.

scholarly journals Trends in agriculture and food production

2009 ◽  
Vol 3 (1-2) ◽  
pp. 99-110
Author(s):  
János Lazányi
Keyword(s):  
Labour Productivity ◽  
Arable Land ◽  
Developed Countries ◽  
Strong Increase ◽  
Small Scale ◽  
Scale Production ◽  
Market Demand ◽  
Total Employment ◽  
Agricultural Reform ◽  
Agricultural Output

Agricultural reform resulted a shift from collective farming to small-scale production in China. This reform also has resulted a strong increase in gross agricultural output, which coincides with a slower increase in labour productivity. At the beginning of the reforms, agriculture accounted for 70 percent of total employment in China and still employs more than 50%. As a result of these reforms, China has undergone impressive economic growth also in the agriculture; the country has become one of the world’s top exporters and is attracting record amounts of foreign investment. The government has also stepped up investments in rural areas to meet the market demand for agricultural products. Results are very competitive compared to Central and Eastern European countries, where agriculture accounted for only 15 percent of total employment, but agricultural reform resulted a strong decline in gross agricultural output, which coincides with a similarly strong decline in employment. When approaching the issue of sustainable agriculture, we have to take into consideration, which China and India feed the largest populations in the world and both countries have had its own agricultural successes in the past 50 years. China has used land far more efficiently than many developed countries. With nine percent of the world’s arable land, China is responsible for the greatest share of agricultural production worldwide. Volume of produced pork, eggs, wheat, cotton, tobacco, and rice has increased and China exports an increasing amount of product each year. China has opened his borders, but do not expose food consumers to price shocks and producers to risks and disincentives. In this paper, the land-tenure system and the trends of agricultural developments are analysed in China and selected countries of EU.

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