Synthesis of Electron Lenses

This paper is a review of different approaches to one of the most ambitious goals of Electron and Ion Optics: to produce elements and systems with prescribed first-order properties and minimal aberrations. Synthesis of such elements is usually done in two steps: the first is a search for a field distribution with the given properties and the second is the reconstruction of electrodes (pole pieces) that would produce this field distribution. The first problem can be solved by the use of different techniques: Calculus of Variations, Dynamic Programming or Function Minimization. The second one is more complicated and requires a lot of ingenuity. Our novel approach takes a different course of action. It combines the two steps into one. Low-aberration field distributions are sought by dynamic programming or function minimization procedures in the form of continuous curves constructed of cubic splines. A very simple algorithm is used for the reconstruction of the electrodes or pole pieces. This approach combines the widely recognized advantages of our optimization techniques with a built-in accurate and effective reconstruction procedure. The final design is simplified on the basis of the requirements of manufacturability. High-quality electrostatic lenses have been designed by the use of this technique. Thus, electron and ion optical synthesis has been transformed from a dream to reality

Testing numerical relativity with the shifted gauge wave

Computational methods are essential to provide waveforms from coalescing black holes, which are expected to produce strong signals for the gravitational wave observatories being developed. Although partial simulations of the coalescence have been reported, scientifically useful waveforms have so far not been delivered. The goal of the AppleswithApples (AwA) Alliance is to design, coordinate and document standardized code tests for comparing numerical relativity codes. The first round of AwA tests have now being completed and the results are being analyzed. These initial tests are based upon periodic boundary conditions designed to isolate performance of the main evolution code. Here we describe and carry out an additional test with periodic boundary conditions which deals with an essential feature of the black hole excision problem, namely a non-vanishing shift. The test is a shifted version of the existing AwA gauge wave test. We show how a shift introduces an exponentially growing instability which violates the constraints of a standard harmonic formulation of Einstein's equations. We analyze the Cauchy problem in a harmonic gauge and discuss particular options for suppressing instabilities in the gauge wave tests. We implement these techniques in a finite difference evolution algorithm and present test results. Although our application here is limited to a model problem, the techniques should benefit the simulation of black holes using harmonic evolution codes

Exploiting gauge and constraint freedom in hyperbolic formulations of Einstein's equations

We present new many-parameter families of strongly and symmetric hyperbolic formulations of Einstein's equations that include quite general algebraic and live gauge conditions for the lapse. The first system that we present has 30 variables and incorporates an algebraic relationship between the lapse and the determinant of the three metric that generalizes the densitized lapse prescription. The second system has 34 variables and uses a family of live gauges that generalizes the Bona-Masso slicing conditions. These systems have free parameters even after imposing hyperbolicity and are expected to be useful in 3D numerical evolutions. We discuss under what conditions there are no superluminal characteristic speeds

Childhood adversity and parent perceptions of child resilience

Abstract Background Adverse childhood experiences (ACEs) negatively impact health throughout the life course. For children exposed to ACEs, resilience may be particularly important. However, the literature regarding resilience, particularly the self-regulation aspect of resilience, is not often described in children with ACEs. Additionally, family and community factors that might help promote resilience in childhood may be further elucidated. We aimed to describe the relationship between ACEs and parent-perceived resilience in children and examine the child, family, and community-level factors associated with child resilience. Methods Using the US-based, 2011–2012 National Survey of Children’s Health, we examined adverse childhood experiences (NSCH-ACEs) as the main exposure. Affirmative answers to adverse experiences generated a total parent-reported NSCH-ACE score. Bivariate and multivariable logistic regression models were constructed for parent-perceived child resilience and its association with ACEs, controlling for child, family, and neighborhood-level factors. Results Among 62,200 US children 6–17 years old, 47% had 0 ACEs, 26% had 1 ACE, 19% had 2–3 ACEs, and 8% had 4 or more ACEs. Child resilience was associated with ACEs in a dose-dependent relationship: as ACEs increased, the probability of resilience decreased. This relationship persisted after controlling for child, family, and community factors. Specific community factors, such as neighborhood safety (p < .001), neighborhood amenities (e.g., libraries, parks) (p < .01) and mentorship (p < .05), were associated with significantly higher adjusted probabilities of resilience, when compared to peers without these specific community factors. Conclusions While ACEs are common and may be difficult to prevent, there may be opportunities for health care providers, child welfare professionals, and policymakers to strengthen children and families by supporting community-based activities, programs, and policies that promote resilience in vulnerable children and communities in which they live.https://deepblue.lib.umich.edu/bitstream/2027.42/144527/1/12887_2018_Article_1170.pd

Cost effectiveness of school-located influenza vaccination programs for elementary and secondary school children.

BackgroundStudies have noted variations in the cost-effectiveness of school-located influenza vaccination (SLIV), but little is known about how SLIV's cost-effectiveness may vary by targeted age group (e.g., elementary or secondary school students), or vaccine consent process (paper-based or web-based). Further, SLIV's cost-effectiveness may be impacted by its spillover effect on practice-based vaccination; prior studies have not addressed this issue.MethodsWe performed a cost-effectiveness analysis on two SLIV programs in upstate New York in 2015-2016: (a) elementary school SLIV using a stepped wedge design with schools as clusters (24 suburban and 18 urban schools) and (b) secondary school SLIV using a cluster randomized trial (16 suburban and 4 urban schools). The cost-per-additionally-vaccinated child (i.e., incremental cost-effectiveness ratio (ICER)) was estimated by dividing the incremental SLIV intervention cost by the incremental effectiveness (i.e., the additional number of vaccinated students in intervention schools compared to control schools). We performed deterministic analyses, one-way sensitivity analyses, and probabilistic analyses.ResultsThe overall effectiveness measure (proportion of children vaccinated) was 5.7 and 5.5 percentage points higher, respectively, in intervention elementary (52.8%) and secondary schools (48.2%) than grade-matched control schools. SLIV programs vaccinated a small proportion of children in intervention elementary (5.2%) and secondary schools (2.5%). In elementary and secondary schools, the ICER excluding vaccine purchase was $85.71 and$86.51 per-additionally-vaccinated-child, respectively. When additionally accounting for observed spillover impact on practice-based vaccination, the ICER decreased to $80.53 in elementary schools -- decreasing substantially in secondary schools. (to$53.40). These estimates were higher than the published practice-based vaccination cost (median = $25.50, mean =$45.48). Also, these estimates were higher than our 2009-2011 urban SLIV program mean costs ($65) due to additional costs for use of a new web-based consent system ($12.97 per-additionally-vaccinated-child) and higher project coordination costs in 2015-2016. One-way sensitivity analyses showed that ICER estimates were most sensitive to the SLIV effectiveness.ConclusionsSLIV raises vaccination rates and may increase practice-based vaccination in primary care practices. While these SLIV programs are effective, to be as cost-effective as practice-based vaccination our SLIV programs would need to vaccinate more students and/or lower the costs for consent systems and project coordination.Trial registrationClinicalTrials.gov NCT02227186 (August 25, 2014), updated NCT03137667 (May 2, 2017)

Surname Repetition and Isonymy in Northeastern Hungarian Marriages

This is the published version. Copyright 1990 Wayne State University Press.The repeated-pair (RP) approach to surnames in married couples is a measure of population subdivision resulting from the influence of lineagelike behavior in mate choice. An excess of RP over random RP implies limitations in mate choice and a reduction of genetic variability. Here we apply the RP method to data from the rural populations of Csaroda, Tiszaadony, and Tiszavid in northeastern Hungary. The results indicate small differences between RP and random RP for Tiszavid and somewhat larger differences for Tiszaadony and Csaroda. The excess of RP over random RP in Tiszavid, however, derives primarily from marriages simultaneously isonymous and repeating in only one lineage. The discrepancy between RP and random RP implies a small reduction in genetic variability

Neutron star-black hole mergers with a nuclear equation of state and neutrino cooling: Dependence in the binary parameters

We present a first exploration of the results of neutron star-black hole mergers using black hole masses in the most likely range of $7M_\odot-10M_\odot$, a neutrino leakage scheme, and a modeling of the neutron star material through a finite-temperature nuclear-theory based equation of state. In the range of black hole spins in which the neutron star is tidally disrupted ($\chi_{\rm BH}\gtrsim 0.7$), we show that the merger consistently produces large amounts of cool ($T\lesssim 1\,{\rm MeV}$), unbound, neutron-rich material ($M_{\rm ej}\sim 0.05M_\odot-0.20M_\odot$). A comparable amount of bound matter is initially divided between a hot disk ($T_{\rm max}\sim 15\,{\rm MeV}$) with typical neutrino luminosity $L_\nu\sim 10^{53}\,{\rm erg/s}$, and a cooler tidal tail. After a short period of rapid protonization of the disk lasting $\sim 10\,{\rm ms}$, the accretion disk cools down under the combined effects of the fall-back of cool material from the tail, continued accretion of the hottest material onto the black hole, and neutrino emission. As the temperature decreases, the disk progressively becomes more neutron-rich, with dimmer neutrino emission. This cooling process should stop once the viscous heating in the disk (not included in our simulations) balances the cooling. These mergers of neutron star-black hole binaries with black hole masses $M_{\rm BH}\sim 7M_\odot-10M_\odot$ and black hole spins high enough for the neutron star to disrupt provide promising candidates for the production of short gamma-ray bursts, of bright infrared post-merger signals due to the radioactive decay of unbound material, and of large amounts of r-process nuclei.Comment: 20 pages, 19 figure

Geometrical optics analysis of the short-time stability properties of the Einstein evolution equations

Many alternative formulations of Einstein's evolution have lately been examined, in an effort to discover one which yields slow growth of constraint-violating errors. In this paper, rather than directly search for well-behaved formulations, we instead develop analytic tools to discover which formulations are particularly ill-behaved. Specifically, we examine the growth of approximate (geometric-optics) solutions, studied only in the future domain of dependence of the initial data slice (e.g. we study transients). By evaluating the amplification of transients a given formulation will produce, we may therefore eliminate from consideration the most pathological formulations (e.g. those with numerically-unacceptable amplification). This technique has the potential to provide surprisingly tight constraints on the set of formulations one can safely apply. To illustrate the application of these techniques to practical examples, we apply our technique to the 2-parameter family of evolution equations proposed by Kidder, Scheel, and Teukolsky, focusing in particular on flat space (in Rindler coordinates) and Schwarzchild (in Painleve-Gullstrand coordinates).Comment: Submitted to Phys. Rev.