5,882 research outputs found
Establishment of a Unified Country-Wide Plane Coordinate System For Zambia
A thesis in EngineeringPlanet Earth is approximately spherical in shape, and is three dimensional. To map the Earth on
a flat piece of paper, in two dimensions, a map projection must be carried out. A map
projection is a mathematical technique of how to represent the Earthâs curved surface on a flat
surface. In Zambia, the map projection used for national mapping is the Universal Transverse
Mercator (UTM) in 6 degree zones. Globally UTM zones run from zone 1 to zone 60 with
Zambia falling onto zones 34, 35 and 36, and with central meridians at 21â° E, 27â° E and 33â° E,
respectively. The central meridians and the equator form three separate plane coordinate
systems, with origins at the intersection of the equator and the particular central meridian.
Map projections come with distortions since there is âstretchingâ or âshrinkingâ of the curved
surface of the reference ellipsoid or spheroid. In order to compute distortions, a scale factor is
introduced to determine scale errors from the central meridian. For UTM projection the scale
factor at the central meridian is 0.9996. To avoid negative coordinates for the southern
hemisphere and the western part of the central meridian, a false easting and northing of
500,000m and 10,000,000m are introduced, respectively.
The problem with the UTM projection system is that data from different zones cannot easily be
combined to create integrated, seamless maps of geographic features across zone boundaries.
Therefore, in this study, the UTM projection and grid system was modified to cover the whole
country Zambia in a single zone. To achieve this, a computer program was written to determine
the scale factor at central meridian suitable for country-wide mapping. The central meridian
was set to 28â° E, and the scale factor at the central meridian was reduced to 0.9984 to minimise
the mean scale error of mapping. A False-Easting of 800,000m was applied to eliminate
negative coordinates, while a False-Northing of 10,000,000m was maintained.
The new plane coordinate system is intended to be used for country-wide, seamless
landcover/use mapping projects such as Task 151 of the Southern African Science Service
Centre for Climate Change and Adaptive Land Management (SASSCAL) project
Composable entropy and deviation from macroscopic equilibrium
We formulate, under general conditions, the problem of maximisation of the
total entropy of the system, assumed to be in a composable form, for fixed
total value of the constrained quantity. We derive the general form of the
composability function and also point out the criterion which leads to a
violation of the zeroth law of thermodynamics.Comment: 10 pages, Latex, no figure
Snowmass 2001: Jet Energy Flow Project
Conventional cone jet algorithms arose from heuristic considerations of LO
hard scattering coupled to independent showering. These algorithms implicitly
assume that the final states of individual events can be mapped onto a unique
set of jets that are in turn associated with a unique set of underlying hard
scattering partons. Thus each final state hadron is assigned to a unique
underlying parton. The Jet Energy Flow (JEF) analysis described here does not
make such assumptions. The final states of individual events are instead
described in terms of flow distributions of hadronic energy. Quantities of
physical interest are constructed from the energy flow distribution summed over
all events. The resulting analysis is less sensitive to higher order
perturbative corrections and the impact of showering and hadronization than the
standard cone algorithms.Comment: REVTeX4, 13 pages, 6 figures; Contribution to the P5 Working Group on
QCD and Strong Interactions at Snowmass 200
Circulating interleukin-10 and risk of cardiovascular events: a prospective study in the elderly at risk
<p><b>Objective:</b> The goal of this study was to examine the association of the antiinflammatory interleukin-10 (IL-10) with risk of cardiovascular disease (CVD).</p>
<p><b>Methods and Results:</b> In the PROSPER (PROspective Study of Pravastatin in the Elderly at Risk) cohort, we related baseline concentrations of circulating IL-10 to risk of CVD events in a nested case (n=819)-control (n=1618) study of 3.2 years of follow-up. Circulating IL-10 showed few strong associations with classical risk factors but was positively correlated with IL-6 and C-reactive protein. IL-10 was positively associated with risk of CVD events (odds ratio [OR] 1.17, 95% CI 1.05 to 1.31 per unit increase in log IL-10) after adjusting for classical risk factors and C-reactive protein. Furthermore, IL-10 was associated more strongly with CVD risk among those with no previous history of CVD (OR 1.42, 95% CI 1.18 to 1.70), compared with those with previous CVD (OR 1.04, 95% CI 0.90 to 1.19; P=0.018). Overall, IL-10 showed a modest ability to add discrimination to classical risk factors (C-statistic +0.005, P=0.002).</p>
<p><b>Conclusion:</b> Baseline circulating levels of the antiinflammatory IL-10 are positively associated with risk of CVD among the elderly without prior CVD events, although the association is less evident in those with a history of CVD. Additional epidemiological and mechanistic studies investigating the role of IL-10 in CVD are warranted.</p>
On the presentation of the LHC Higgs Results
We put forth conclusions and suggestions regarding the presentation of the
LHC Higgs results that may help to maximize their impact and their utility to
the whole High Energy Physics community.Comment: Conclusions from the workshops "Likelihoods for the LHC Searches",
21-23 January 2013 at CERN, "Implications of the 125 GeV Higgs Boson", 18-22
March 2013 at LPSC Grenoble, and from the 2013 Les Houches "Physics at TeV
Colliders" workshop. 16 pages, 3 figures. Version 2: Comment added on the
first publication of signal strength likelihoods in digital form by ATLA
Evaluation of the KEMRI Hep-cell II test kit for detection of hepatitis B surface antigens in Tanzania
Hepatitis B surface antigen (HBsAg) is one of the most important serological markers used to diagnose acute and chronic hepatitis B infection. The objective of the current evaluation was to assess the operational characteristics of the Kenya Medical Research Institute (KEMRI) Hep-cell II against an ELISA Exsym HBsAg in the detection of hepatitis B surface antigens. To evaluate the Hep-cell II test, blood samples were collected from blood donors and processed for detection of HBsAg using Hep-cell II based on the test principle and procedure outlined by the manufacturer. ELISA Axsym HBsAg test was used as golden standard. Of the 400 samples tested, 287 (71.8%) were positive by Hep-cell test and 295 (73.8%) were positive by the ELISA Axsym. Hep-cell test had a sensitivity of 98.6% and specificity of 95.96%. Similar values of sensitivity and specificity of the Hep-cell test were obtained even when Bayesian Analysis Model was applied. The positive and negative predictive values of Hep-cell test were 98.61% and 95.96%, respectively. The positive and negative diagnostic likelihood ratios of Hep-cell test were 24.4% and 0.0145, respectively. In conclusion, the Hep-cell test is useful for detecting hepatitis B virus and the high likelihood ratio observed suggests that it may be useful in blood screening. However, it may be necessary to evaluate for cost-effectiveness and robustness in field conditions before the test is recommended for use
Measuring, manipulating and exploiting behaviours of adult mosquitoes to optimise malaria vector control impact.
Residual malaria transmission can persist despite high coverage with effective long-lasting insecticidal nets (LLINs) and/or indoor residual spraying (IRS), because many vector mosquitoes evade them by feeding on animals, feeding outdoors, resting outdoors or rapidly exiting from houses after entering them. However, many of these behaviours that render vectors resilient to control with IRS and LLINs also make them vulnerable to some emerging new alternative interventions. Furthermore, vector control measures targeting preferred behaviours of mosquitoes often force them to express previously rare alternative behaviours, which can then be targeted with these complementary new interventions. For example, deployment of LLINs against vectors that historically fed predominantly indoors on humans typically results in persisting transmission by residual populations that survive by feeding outdoors on humans and animals, where they may then be targeted with vapour-phase insecticides and veterinary insecticides, respectively. So while the ability of mosquitoes to express alternative behaviours limits the impact of LLINs and IRS, it also creates measurable and unprecedented opportunities for deploying complementary additional approaches that would otherwise be ineffective. Now that more diverse vector control methods are finally becoming available, well-established entomological field techniques for surveying adult mosquito behaviours should be fully exploited by national malaria control programmes, to rationally and adaptively map out new opportunities for their effective deployment
Top Quark Physics at the Tevatron
The discovery of the top quark in 1995, by the CDF and D0 collaborations at
the Fermilab Tevatron, marked the dawn of a new era in particle physics. Since
then, enormous efforts have been made to study the properties of this
remarkable particle, especially its mass and production cross section. In this
article, we review the status of top quark physics as studied by the two
collaborations using the p-pbar collider data at sqrt(s) = 1.8 TeV. The
combined measurement of the top quark mass, m_t = 173.8 +- 5.0 GeV/c^2, makes
it known to a fractional precision better than any other quark mass. The
production cross sections are measured as sigma (t-tbar) = 7.6 -1.5 +1.8 pb by
CDF and sigma (t-tbar) = 5.5 +- 1.8 pb by D0. Further investigations of t-tbar
decays and future prospects are briefly discussed.Comment: 119 pages, 59 figures, 17 tables Submitted to Int. J. Mod. Phys. A
Fixed some minor error
Snowmass 2001: Jet Energy Flow Project
Conventional cone jet algorithms arose from heuristic considerations of LO hard scattering coupled to independent showering. These algorithms implicitly assume that the final states of individual events can be mapped onto a unique set of jets that are in turn associated with a unique set of underlying hard scattering partons. Thus each final state hadron is assigned to a unique underlying parton. The Jet Energy Flow (JEF) analysis described here does not make such assumptions. The final states of individual events are instead described in terms of flow distributions of hadronic energy. Quantities of physical interest are constructed from the energy flow distribution summed over all events. The resulting analysis is less sensitive to higher order perturbative corrections and the impact of showering and hadronization than the standard cone algorithms
Use of Artificial Neural Networks for Improvement of CMS Hadron Calorimeter Resolution
The Compact Muon Solenoid (CMS) experiment features an electromagnetic calorimeter (ECAL) composed of lead tungstate crystals and a sampling hadronic calorimeter (HCAL) made of brass and scintillator, along with other detectors. For hadrons, the response of the electromagnetic and hadronic calorimeters is inherently different. Because sampling calorimeters measure a fraction of the energy spread over several measuring towers, the energy resolution as well as the linearity are not easily preserved, especially at low energies. Several sophisticated algorithms have been developed to optimize the resolution of the CMS calorimeter system for single particles. One such algorithm, based on the artificial neural network application to the combined electromagnetic and hadronic calorimeter system, was developed and applied to test beam data using particles in the momentum range of 2-300 GeV/c. The method improves the energy measurement and linearity, especially at low energies below 10 GeV/c
- âŠ