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Search Results: 1 - 10 of 219381 matches for " C. Arrowsmith "
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Local δ18O and δ2H variability in UK rainfall
M. D. Jones,M. J. Leng,C. Arrowsmith,C. Deuchars
Hydrology and Earth System Sciences Discussions , 2007,
Abstract: Rainfall collected twice weekly from 3 nearby UK stations between November 2004 and October 2006 allows local differences in δ18O and δ2H to be observed. Local gradients in δ18Op appear to be of the same order of magnitude as national trends, suggesting the spatial δ18Op picture is more complicated than the one currently available from sparse GNIP coverage. Comparing data from this study with previous work we find that average δ18Op has changed in the UK over the last 20 years concurrent with an average temperature increase although inter-annual controls on the values remain seasonal temperature and the amount of precipitation in each rain event. Climate-isotope relationships observed from the weekly data do not explain the observed decadal scale shifts.
Cruciform structures are a common DNA feature important for regulating biological processes
Václav Brázda, Rob C Laister, Eva B Jagelská, Cheryl Arrowsmith
BMC Molecular Biology , 2011, DOI: 10.1186/1471-2199-12-33
Abstract: Cruciform structures are targets for many architectural and regulatory proteins, such as histones H1 and H5, topoisomerase IIβ, HMG proteins, HU, p53, the proto-oncogene protein DEK and others. A number of DNA-binding proteins, such as the HMGB-box family members, Rad54, BRCA1 protein, as well as PARP-1 polymerase, possess weak sequence specific DNA binding yet bind preferentially to cruciform structures. Some of these proteins are, in fact, capable of inducing the formation of cruciform structures upon DNA binding. In this article, we review the protein families that are involved in interacting with and regulating cruciform structures, including (a) the junction-resolving enzymes, (b) DNA repair proteins and transcription factors, (c) proteins involved in replication and (d) chromatin-associated proteins. The prevalence of cruciform structures and their roles in protein interactions, epigenetic regulation and the maintenance of cell homeostasis are also discussed.Genome sequencing projects have inundated us with information regarding the genetic basis of life. While this wealth of information provides a foundation for our understanding of biology, it has become clear that the DNA code alone does not hold all the answers. Epigenetic modifications and higher order DNA structures beyond the double helix also contribute to basic biological processes and maintaining cellular stability. Local alternative DNA structures are known to exist in all life forms [1]. The negative supercoiling of DNA can induce local nucleotide sequence-dependent conformational changes that give rise to cruciforms, left-handed DNA, triplexes and quadruplexes [2-4]. The formation of cruciforms is strongly dependent on base sequence and requires perfect or imperfect inverted repeats of 6 or more nucleotides in the DNA sequence [5,6]. Over-representation of inverted repeats, which occurs nonrandomly in the DNA of all organisms, has been noted in the vicinity of breakpoint junctions, promoter region
The colour of electroplated golds
David J. Arrowsmith
Gold Bulletin , 1986, DOI: 10.1007/BF03214651
Abstract: The origin of the colour of gold and gold alloy electrodeposits is discussed, whether any new colours may be expected, and whether theory may be used to predict the colour of new alloys.
Application of GIS for Mapping Rainwater-Harvesting Potential: Case Study Wollert, Victoria  [PDF]
Sultana Nasrin Baby, Colin Arrowsmith, Nadhir Al-Ansari
Engineering (ENG) , 2019, DOI: 10.4236/eng.2019.111002
Abstract: Water is a basic normal asset for supporting the condition of life. Accessible water assets are feeling the squeeze because of expanding demand. Soon water, which we have depended upon to be accessible and an unconditional present of nature will turn into a rare product. Protection and conservation of water assets are desperately required. In many parts of Victoria, water supply to communities is limited. Rainwater harvesting systems can provide water at or near the point of demand. The systems can be owner and utility operated and managed. Rainwater collected using existing structures, i.e. rooftops, parking lots, playgrounds, parks, ponds, floodplains etc., has few negative environmental impacts compared to other technologies for water resources development. Rainwater is relatively clean and the quality is usually acceptable for many purposes with little or even no treatment. The physical and chemical properties of rainwater are usually superior to sources of groundwater that may have been subjected to contamination. The present study was intended to measure the rooftop rainwater harvesting potential using GIS techniques. The GIS examination utilized in this investigation was basically an efficient assessment of rooftop water collecting in the chose Wollert which is a suburb in Melbourne, Victoria. With the use of GIS it was conceivable to appraise the aggregate sum of water harvestable at the household level. It is very tedious work to assess the catchments available for rooftop rainwater harvesting. Here the roof surfaces are the catchments and GIS is employed to calculate the area of various types of roofs and their potential for planning for the area under study. As a result Eucalypt Estate Wollert has huge potential and can make above 179.11 litres water available per person per day throughout the year.
A Sources-of-Error Model for Acoustic/Infrasonic Yield Estimation for Above-Ground Single-Point Explosions  [PDF]
Stephen J. Arrowsmith, Rodney W. Whitaker, Jonathan K. Maccarthy, Dale N. Anderson
InfraMatics (InfraMatics) , 2012, DOI: 10.4236/inframatics.2012.11001
Abstract: Acoustic/infrasonic measurements contain physical information enabling an estimate of the yield of a single-point explosion that is on or above ground. A variety of semi-empirical and numerical models have been developed for estimating the yield based on the amplitude of a recorded acoustic signal. This paper utilizes existing semi-empirical models-suitable for timely yield estimation—and develops the mathematical framework to properly account for uncertainties in these models, in addition to measurement uncertainties. The inclusion of calibration parameters into our mathematical model allows for the correction of constant path specific effects that are not captured in existing semi-empirical models. The calibrated model provides a yield estimate and associated error bounds that correctly partitions total error into model error and background noise. Yield estimation with the models is demonstrated with single-point, above ground chemical explosions at Los Alamos National Laboratory (LANL) experimental testing facilities.
Communication models with distributed transmission rates and buffer sizes
David Arrowsmith,Mario di Bernardo,Francesco Sorrentino
Physics , 2006,
Abstract: The paper is concerned with the interplay between network structure and traffic dynamics in a communications network, from the viewpoint of end-to-end performance of packet transfer. We use a model of network generation that allows the transition from random to scale-free networks. Specifically, we are able to consider three different topologycal types of networks: (a) random; (b) scale-free with \gamma=3; (c) scale free with \gamma=2. We also use an LRD traffic generator in order to reproduce the fractal behavior that is observed in real world data communication. The issue is addressed of how the traffic behavior on the network is influenced by the variable factors of the transmission rates and queue length restrictions at the network vertices. We show that these factors can induce drastic changes in the throughput and delivery time of network performance and are able to counter-balance some undesirable effects due to the topology.
Effects of variations of load distribution on network performance
David Arrowsmith,Mario di Bernardo,Francesco Sorrentino
Computer Science , 2005,
Abstract: This paper is concerned with the characterization of the relationship between topology and traffic dynamics. We use a model of network generation that allows the transition from random to scale free networks. Specifically, we consider three different topological types of network: random, scale-free with \gamma = 3, scale-free with \gamma = 2. By using a novel LRD traffic generator, we observe best performance, in terms of transmission rates and delivered packets, in the case of random networks. We show that, even if scale-free networks are characterized by shorter characteristic-path- length (the lower the exponent, the lower the path-length), they show worst performances in terms of communication. We conjecture this could be explained in terms of changes in the load distribution, defined here as the number of shortest paths going through a given vertex. In fact, that distribu- tion is characterized by (i) a decreasing mean (ii) an increas- ing standard deviation, as the networks becomes scale-free (especially scale-free networks with low exponents). The use of a degree-independent server also discriminates against a scale-free structure. As a result, since the model is un- controlled, most packets will go through the same vertices, favoring the onset of congestion.
Spatial Decision Support System for Coastal Zone Management under a Changing Climate in Victoria, Australia  [PDF]
Sultana Nasrin Baby, Colin Arrowsmith, Nadhir Al-Ansari, Nahlah Abbas
Engineering (ENG) , 2018, DOI: 10.4236/eng.2018.1010046
Abstract: The ultimate aim of using spatial datasets and spatial data modelling is focused on enabling a sustainable environment by bringing the public policies into practice. The consequence will be sustainable spatially aware strategic planning for all levels of Australian government. Geographical Information Systems (GIS) are the platform that can serve this aim provided that model, current process and spatial datasets are fit for purpose. To bring public policy into practice a broad range of knowledge from different disciplines is needed. Most decision making processes are pressured in terms of time and driving forces and also the process is beyond the knowledge of individuals in the various disciplines. There is a need for immediate uptake models and tools which are relevant to the target subject that will facilitate this decision making process. This paper focuses on realizing the utility in spatial data and spatial data handling in order to help climate change adaptation programs at local government level. Web-based mapping tools can assist planners prepare for the changing climate conditions in Bass Coast Shire Council. The GIS team has gathered data from various climate research organizations to understand projections of what different climate scenarios might look like over the next 100-year period. From this website demo it is hoped that the user will understand how the tool works, background information on different GIS platforms, access to interactive mapping, online geospatial analysis tools, videos, open source resource, sea level tools, modelling, 3D visualization and direct download access to various planning and natural resource data sets relating to environment management. Some results from our elevation data analyses through these Web map visualization tools are provided.
Poor Spontaneous and Oxytocin-Stimulated Contractility in Human Myometrium from Postdates Pregnancies
Sarah Arrowsmith, Siobhan Quenby, Andrew Weeks, Theodor Burdyga, Susan Wray
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036787
Abstract: Prolongation of pregnancy i.e. going more than 10 days over the estimated due date, complicates up to 10% of all pregnancies and is associated with increased risk to both mother and fetus. Despite the obvious need for contractions of the uterus to end pregnancy, there have been no studies directly examining the role of uterine smooth muscle, myometrium, in the aetiology of prolonged pregnancy. This study tested the hypothesis that the intrinsic contractile characteristics of myometrium taken from women with prolonged pregnancy (>41 weeks and 3 days) was reduced compared to those delivering at term (39–41 weeks). We recruited women undergoing Caesarean Section (CS) delivery either pre-labour (n = 27) or in labour (n = 66) at term or postdates. The contractile ability of the postdates myometrium, whether spontaneous or elicited by oxytocin or high-K solution, was significantly reduced compared to term myometrium. These differences remained when adjusted for parity and other maternal characteristics. The findings remained significant when expressed per cross sectional area. Histological examination revealed no differences between the two groups. The contractile differences were however related to intracellular Ca transients suggesting an effect of [Ca] on reduced force production in the postdates group. In summary, myometrium from prolonged pregnancies contracts poorly in vitro even when stimulated with oxytocin and in active labour. Responses to high K+ and measurements of Ca suggest that alterations in excitation contraction coupling, rather than any histological changes of the myometrium, may underlie the differences between term and postdates myometrium. We show that postdates pregnancy is associated with poor myometrial activity and suggest that this may contribute to increased myometrial quiescence and hence, prolonged gestation.
Current practices in treatment of female genital fistula: a cross sectional study
Steven D Arrowsmith, Joseph Ruminjo, Evelyn G Landry
BMC Pregnancy and Childbirth , 2010, DOI: 10.1186/1471-2393-10-73
Abstract: Self-administered questionnaires were completed by 40 surgeons known to provide fistula treatment services in Africa and Asia at private and government hospitals. The questionnaire was divided into three parts to address the following issues: prophylactic use of antibiotics before, during, and after fistula surgery; urethral catheter management; and management practices for patients with urinary incontinence following fistula repair.The results provide a glimpse into current practices in fistula treatment and care across a wide swath of geographic, economic, and organizational considerations. There is consensus in treatment in some areas (routine use of prophylactic antibiotics, limited bed rest until the catheter is removed, nonsurgical treatment for postsurgical incontinence), while there are wide variations in practice in other areas (duration of catheter use, surgical treatments for postsurgical incontinence). These findings are based on a small sample and do not allow for recommending changes in clinical care, but they point to issues for possible clinical trial research that would contribute to more efficient and effective fistula care.The findings from the survey allowed us to consider clinical practices most influential in the cost, efficacy, and safety of fistula treatment. These considerations led us to formulate recommendations for eight randomized controlled trials on the following subjects: 1) Efficacy/safety of short-term catheterization; 2) efficacy of surgical and nonsurgical therapies for urinary incontinence; 3) technical measures during fistula repair to reduce the incidence of post-surgery incontinence; 4) identification of predictive factors for "incurable fistula"; 5) usefulness of urodynamic studies in the management of urinary incontinence; 6) incidence and significance of multi-drug resistant bacteria in the fistula population; 7) primary management of small, new fistulas by catheter drainage; and 8) antibiotic prophylaxis in fistula repair.
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