604 research outputs found
Helping Babies Survive Training Programs: Evaluating a Teaching Cascade in Ethiopia
Background: 2.6 million neonates die annually; the vast majority of deaths occur in low- and middle-income countries (LMICs). The Helping Babies Survive (HBS) programs are commonly used in LMICs to reduce neonatal mortality through education. They are typically disseminated using a train-the-trainer cascade. However, there is little published literature on the extent and cost of dissemination. In 2015, the Ethiopian Ministry of Health and partner organizations implemented a countrywide HBS training cascade for midwives in 169 hospitals.Methods: We quantified the extent of HBS dissemination, and characterized barriers that impeded successful hospital-based training by surveying a representative from each of the 169 participant hospitals. This occurred from September 2017 to April 2018. We also assessed the cost of the training cascade. To assess acquisition of knowledge and skill in the training cascade, multiple-choice question examinations (MCQE) and objective structured clinical evaluations (OSCE) were conducted.Results: Hospital-based training occurred in 132 participant hospitals (78%). 1,146 midwives, 69% of those employed by participant hospitals, received hospital-based training. Barriers included lack of preparation of hospital-based educators and limited logistical support. The cascade cost an average of 2,105 USD per facility or 197 USD per trainee. Knowledge improved and skills were adequate for regional workshop attendees based on MCQE and OSCE performance.Conclusion: The train-the-trainer strategy is an effective and affordable strategy for widespread dissemination of the HBS programs in LMICs. Future studies should assess knowledge and skill acquisition following the variety of pragmatic training approaches that may be employed at the facility-level
Measurement of interfacial tension of immiscible liquid pairs in microgravity
A discussion is given of a containerless microgravity experiment aimed at measuring the interfacial tension of immiscible liquid pairs using a compound drop rotation method. The reasons for the failure to execute such experiments in microgravity are described. Also, the results of post-flight analyses used to confirm our arguments are presented
Spin Path Integrals and Generations
The spin of a free electron is stable but its position is not. Recent quantum
information research by G. Svetlichny, J. Tolar, and G. Chadzitaskos have shown
that the Feynman \emph{position} path integral can be mathematically defined as
a product of incompatible states; that is, as a product of mutually unbiased
bases (MUBs). Since the more common use of MUBs is in finite dimensional
Hilbert spaces, this raises the question "what happens when \emph{spin} path
integrals are computed over products of MUBs?" Such an assumption makes spin no
longer stable. We show that the usual spin-1/2 is obtained in the long-time
limit in three orthogonal solutions that we associate with the three elementary
particle generations. We give applications to the masses of the elementary
leptons.Comment: 20 pages, 2 figures, accepted at Foundations of Physic
Electromagnetic Corrections to Pi Pi Scattering: Some Lessons for the Implementation of Meson Exchange Models
The leading non-Coulombic electromagnetic contributions to pi pi s-wave
scattering lengths are computed in Chiral Perturbation Theory. It is shown that
these corrections are zeroth order in the chiral expansion and associated with
electromagnetic contact terms in the effective Lagrangian, i.e. that they do
not involve explicit photon fields in the low-energy effective theory. It is
pointed out that, if one followed the standard meson-exchange-model ansatz for
removing electromagnetic effects, i.e. of subtracting contributions associated
with explicit photon exchange and radiative corrections, as determined by the
photon coupling vertices of the effective hadronic theory, one would completely
miss these contributions and arrive at the erroneous conclusion that the strong
interactions exhibited very large isospin breaking in pi pi scattering.
Implications for electromagnetic "subtraction" procedures in other hadronic
systems and the utility of the effective Lagrangian method for avoiding such
errors are obvious.Comment: 16 pages, REVTE
PT-Symmetric Quantum Electrodynamics
The Hamiltonian for quantum electrodynamics becomes non-Hermitian if the
unrenormalized electric charge is taken to be imaginary. However, if one
also specifies that the potential in such a theory transforms as a
pseudovector rather than a vector, then the Hamiltonian becomes PT symmetric.
The resulting non-Hermitian theory of electrodynamics is the analog of a
spinless quantum field theory in which a pseudoscalar field has a cubic
self-interaction of the form . The Hamiltonian for this cubic scalar
field theory has a positive spectrum, and it has recently been demonstrated
that the time evolution of this theory is unitary. The proof of unitarity
requires the construction of a new operator called C, which is then used to
define an inner product with respect to which the Hamiltonian is self-adjoint.
In this paper the corresponding C operator for non-Hermitian quantum
electrodynamics is constructed perturbatively. This construction demonstrates
the unitarity of the theory. Non-Hermitian quantum electrodynamics is a
particularly interesting quantum field theory model because it is
asymptotically free.Comment: 9 pages, no figures, revtex
New Approach to Quantum Field Theory for Arbitrary Observers in Electromagnetic Backgrounds
A reformulation of fermionic QFT in electromagnetic backgrounds is presented
which uses methods analogous to those of conventional multiparticle quantum
mechanics. Emphasis is placed on the (Schr\"odinger picture) states of the
system, described in terms of Slater determinants of Dirac states, and not on
the field operator (which is superfluous in this approach). The
vacuum state `at time ' is defined as the Slater determinant of a basis
for the span of the negative spectrum of the `first quantized' Hamiltonian
, thus providing a concrete realisation of the Dirac Sea. The
general S-matrix element of the theory is derived in terms of time-dependent
Bogoliubov coefficients, demonstrating that the S-matrix follows directly from
the definition of inner product between Slater determinants. The process of
`Hermitian extension', inherited directly from conventional multiparticle
quantum mechanics, allows second quantized operators to be defined without
appealing to a complete set of orthonormal modes, and provides an extremely
straightforward derivation of the general expectation value of the theory. The
concept of `radar time', advocated by Bondi in his work on k-calculus, is used
to generalise the particle interpretation to an arbitrarily moving observer. A
definition of particle results, which depends {\it only} on the observer's
motion and the background present, not on any choice of coordinates or gauge,
or of the particle detector. We relate this approach to conventional methods by
comparing and contrasting various derivations. Our particle definition can be
viewed as a generalisation to arbitrary observers of Gibbons' approach.Comment: 36 pages, 3 figure
Angular Conditions,Relations between Breit and Light-Front Frames, and Subleading Power Corrections
We analyze the current matrix elements in the general collinear (Breit)
frames and find the relation between the ordinary (or canonical) helicity
amplitudes and the light-front helicity amplitudes. Using the conservation of
angular momentum, we derive a general angular condition which should be
satisfied by the light-front helicity amplitudes for any spin system. In
addition, we obtain the light-front parity and time-reversal relations for the
light-front helicity amplitudes. Applying these relations to the spin-1 form
factor analysis, we note that the general angular condition relating the five
helicity amplitudes is reduced to the usual angular condition relating the four
helicity amplitudes due to the light-front time-reversal condition. We make
some comments on the consequences of the angular condition for the analysis of
the high- deuteron electromagnetic form factors, and we further apply the
general angular condition to the electromagnetic transition between spin-1/2
and spin-3/2 systems and find a relation useful for the analysis of the
N- transition form factors. We also discuss the scaling law and the
subleading power corrections in the Breit and light-front frames.Comment: 24 pages,2 figure
Genetic Determinants of Facial Clefting: Analysis of 357 Candidate Genes Using Two National Cleft Studies from Scandinavia
Facial clefts are common birth defects with a strong genetic component. To identify fetal genetic risk factors for clefting, 1536 SNPs in 357 candidate genes were genotyped in two population-based samples from Scandinavia (Norway: 562 case-parent and 592 control-parent triads; Denmark: 235 case-parent triads).We used two complementary statistical methods, TRIMM and HAPLIN, to look for associations across these two national samples. TRIMM tests for association in each gene by using multi-SNP genotypes from case-parent triads directly without the need to infer haplotypes. HAPLIN on the other hand estimates the full haplotype distribution over a set of SNPs and estimates relative risks associated with each haplotype. For isolated cleft lip with or without cleft palate (I-CL/P), TRIMM and HAPLIN both identified significant associations with IRF6 and ADH1C in both populations, but only HAPLIN found an association with FGF12. For isolated cleft palate (I-CP), TRIMM found associations with ALX3, MKX, and PDGFC in both populations, but only the association with PDGFC was identified by HAPLIN. In addition, HAPLIN identified an association with ETV5 that was not detected by TRIMM.Strong associations with seven genes were replicated in the Scandinavian samples and our approach effectively replicated the strongest previously known association in clefting--with IRF6. Based on two national cleft cohorts of similar ancestry, two robust statistical methods and a large panel of SNPs in the most promising cleft candidate genes to date, this study identified a previously unknown association with clefting for ADH1C and provides additional candidates and analytic approaches to advance the field
Thermoluminescence spectra and activation energies for aromatic amino acids, trypsin, and spores of bacillus megaterium
"Date issued Jun 21 1963".Bibliography: l. 112-117.Mode of access: Internet
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