2,447 research outputs found
Developing a distance education programming skills course for geo-information sciences and earth observation students
Maintaining Vaccine Delivery Following the Introduction of the Rotavirus and Pneumococcal Vaccines in Thailand
Although the substantial burdens of rotavirus and pneumococcal disease have motivated many countries to consider introducing the rotavirus vaccine (RV) and heptavalent pneumococcal conjugate vaccine (PCV-7) to their National Immunization Programs (EPIs), these new vaccines could affect the countries' vaccine supply chains (i.e., the series of steps required to get a vaccine from their manufacturers to patients). We developed detailed computational models of the Trang Province, Thailand, vaccine supply chain to simulate introducing various RV and PCV-7 vaccine presentations and their combinations. Our results showed that the volumes of these new vaccines in addition to current routine vaccines could meet and even exceed (1) the refrigerator space at the provincial district and sub-district levels and (2) the transport cold space at district and sub-district levels preventing other vaccines from being available to patients who arrive to be immunized. Besides the smallest RV presentation (17.1 cm3/dose), all other vaccine introduction scenarios required added storage capacity at the provincial level (range: 20 L–1151 L per month) for the three largest formulations, and district level (range: 1 L–124 L per month) across all introduction scenarios. Similarly, with the exception of the two smallest RV presentation (17.1 cm3/dose), added transport capacity was required at both district and sub-district levels. Added transport capacity required across introduction scenarios from the provincial to district levels ranged from 1 L–187 L, and district to sub-district levels ranged from 1 L–13 L per shipment. Finally, only the smallest RV vaccine presentation (17.1 cm3/dose) had no appreciable effect on vaccine availability at sub-districts. All other RV and PCV-7 vaccines were too large for the current supply chain to handle without modifications such as increasing storage or transport capacity. Introducing these new vaccines to Thailand could have dynamic effects on the availability of all vaccines that may not be initially apparent to decision-makers
Challenging SO(10) SUSY GUTs with family symmetries through FCNC processes
We perform a detailed analysis of the SO(10) SUSY GUT model with D3 family
symmetry of Dermisek and Raby (DR). The model is specified in terms of 24
parameters and predicts, as a function of them, the whole MSSM set of
parameters at low energy scales. Concerning the SM subset of such parameters,
the model is able to give a satisfactory description of the quark and lepton
masses, of the PMNS matrix and of the CKM matrix. We perform a global fit to
the model, including flavour changing neutral current (FCNC) processes Bs -->
mu+ mu-, B --> Xs gamma, B --> Xs l+ l- and the B(d,s) - bar B(d,s) mass
differences Delta M(d,s) as well as the flavour changing (FC) process B+ -->
tau+ nu. These observables provide at present the most sensitive probe of the
SUSY mass spectrum and couplings predicted by the model. Our analysis
demonstrates that the simultaneous description of the FC observables in
question represents a serious challenge for the DR model, unless the masses of
the scalars are moved to regions which are problematic from the point of view
of naturalness and probably beyond the reach of the LHC. We emphasize that this
problem could be a general feature of SUSY GUT models with third generation
Yukawa unification and weak-scale minimal flavour violation.Comment: 1 + 37 pages, 5 figures, 11 tables. v3: minor typos fixed. Matches
JHEP published versio
Observer Dependent Horizon Temperatures: a Coordinate-Free Formulation of Hawking Radiation as Tunneling
We reformulate the Hamilton-Jacobi tunneling method for calculating Hawking
radiation in static, spherically-symmetric spacetimes by explicitly
incorporating a preferred family of frames. These frames correspond to a family
of observers tied to a locally static timelike Killing vector of the spacetime.
This formulation separates the role of the coordinates from the choice of
vacuum and thus provides a coordinate-independent formulation of the tunneling
method. In addition, it clarifies the nature of certain constants and their
relation to these preferred observers in the calculation of horizon
temperatures. We first use this formalism to obtain the expected temperature
for a static observer at finite radius in the Schwarzschild spacetime. We then
apply this formalism to the Schwarzschild-de Sitter spacetime, where there is
no static observer with 4-velocity equal to the static timelike Killing vector.
It is shown that a preferred static observer, one whose trajectory is geodesic,
measures the lowest temperature from each horizon. Furthermore, this observer
measures horizon temperatures corresponding to the well-known Bousso-Hawking
normalization.Comment: 11 pages, 1 2-part figure, references added, appendix added,
discussion streamline
Fermions from Half-BPS Supergravity
We discuss collective coordinate quantization of the half-BPS geometries of
Lin, Lunin and Maldacena (hep-th/0409174). The LLM geometries are parameterized
by a single function on a plane. We treat this function as a collective
coordinate. We arrive at the collective coordinate action as well as path
integral measure by considering D3 branes in an arbitrary LLM geometry. The
resulting functional integral is shown, using known methods (hep-th/9309028),
to be the classical limit of a functional integral for free fermions in a
harmonic oscillator. The function gets identified with the classical limit
of the Wigner phase space distribution of the fermion theory which satisfies u
* u = u. The calculation shows how configuration space of supergravity becomes
a phase space (hence noncommutative) in the half-BPS sector. Our method sheds
new light on counting supersymmetric configurations in supergravity.Comment: 28 pages, 2 figures, epsf;(v3) eq. (3.3) clarified and notationally
simplified; version to appear in JHE
Augmenting Transport versus Increasing Cold Storage to Improve Vaccine Supply Chains
Background:When addressing the urgent task of improving vaccine supply chains, especially to accommodate the introduction of new vaccines, there is often a heavy emphasis on stationary storage. Currently, donations to vaccine supply chains occur largely in the form of storage equipment.Methods:This study utilized a HERMES-generated detailed, dynamic, discrete event simulation model of the Niger vaccine supply chain to compare the impacts on vaccine availability of adding stationary cold storage versus transport capacity at different levels and to determine whether adding stationary storage capacity alone would be enough to relieve potential bottlenecks when pneumococcal and rotavirus vaccines are introduced by 2015.Results:Relieving regional level storage bottlenecks increased vaccine availability (by 4%) more than relieving storage bottlenecks at the district (1% increase), central (no change), and clinic (no change) levels alone. Increasing transport frequency (or capacity) yielded far greater gains (e.g., 15% increase in vaccine availability when doubling transport frequency to the district level and 18% when tripling). In fact, relieving all stationary storage constraints could only increase vaccine availability by 11%, whereas doubling the transport frequency throughout the system led to a 26% increase and tripling the frequency led to a 30% increase. Increasing transport frequency also reduced the amount of stationary storage space needed in the supply chain. The supply chain required an additional 61,269L of storage to relieve constraints with the current transport frequency, 55,255L with transport frequency doubled, and 51,791L with transport frequency tripled.Conclusions:When evaluating vaccine supply chains, it is important to understand the interplay between stationary storage and transport. The HERMES-generated dynamic simulation model showed how augmenting transport can result in greater gains than only augmenting stationary storage and can reduce stationary storage needs. © 2013 Haidari et al
Strategy-Proofness and Efficiency with Nonquasi-Linear Preferences: A Characterization of Minimum Price Walrasian Rule
Privacy in crowdsourcing:a systematic review
The advent of crowdsourcing has brought with it multiple privacy challenges. For example, essential monitoring activities, while necessary and unavoidable, also potentially compromise contributor privacy. We conducted an extensive literature review of the research related to the privacy aspects of crowdsourcing. Our investigation revealed interesting gender differences and also differences in terms of individual perceptions. We conclude by suggesting a number of future research directions.</p
The role of riboflavin in decolourisation of Congo red and bioelectricity production using Shewanella oneidensis-MR1 under MFC and non-MFC conditions
Dissimilatory metal reducing bacteria can exchange electrons extracellularly and hold great promise for their use in simultaneous wastewater treatment and electricity production. This study investigated the role of riboflavin, an electron carrier, in the decolourisation of Congo red in microbial fuel cells (MFCs) using Shewanella oneidensis MR-1 as a model organism. The contribution of the membrane-bound protein MtrC to the decolourisation process was also investigated. Within the range of riboflavin concentrations tested, 20 µM was found to be the best with >95% of the dye (initial concentration 200 mg/L) decolourised in MFCs within 50 h compared to 90% in the case where no riboflavin was added. The corresponding maximum power density was 45 mW/m2. There was no significant difference in the overall decolourisation efficiencies of Shewanela oneidensis MR-1 ΔMtrC mutants compared to the wild type. However, in terms of power production the mutant produced more power (Pmax 76 mW/m2) compared to the wild type (Pmax 46 mW/m2) which was attributed to higher levels of riboflavin secreted in solution. Decolourisation efficiencies in non-MFC systems (anaerobic bottles) were similar to those under MFC systems indicating that electricity generation in MFCs does not impair dye decolourisation efficiencies. The results suggest that riboflavin enhances both decolourisation of dyes and simultaneous electricity production in MFCs
Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at TeV
Inclusive transverse momentum spectra of primary charged particles in Pb-Pb
collisions at = 2.76 TeV have been measured by the ALICE
Collaboration at the LHC. The data are presented for central and peripheral
collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross
section. The measured charged particle spectra in and GeV/ are compared to the expectation in pp collisions at the same
, scaled by the number of underlying nucleon-nucleon
collisions. The comparison is expressed in terms of the nuclear modification
factor . The result indicates only weak medium effects ( 0.7) in peripheral collisions. In central collisions,
reaches a minimum of about 0.14 at -7GeV/ and increases
significantly at larger . The measured suppression of high- particles is stronger than that observed at lower collision energies,
indicating that a very dense medium is formed in central Pb-Pb collisions at
the LHC.Comment: 15 pages, 5 captioned figures, 3 tables, authors from page 10,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/98
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