Tables of Seismological Co-latitude

The use of seismological latitude increases the accuracy of computations of great-circle distances and greatly simplifies the ellipticity correction for seismic travel-times. Bullen (1937b, p. 162) shows that the use of seismological latitude allows computations of travel-times with errors less than 0.1 second without recourse to the awkward triple-entry tables needed for complete ellipticity corrections (Bullen, 1937a). The tables in this paper permit conversion of the geographic latitude to seismological co-latitude. The tables are entered by reading the geographic latitude to the nearest unit down the lefthand column and the nearest tenth across the page. Interpolations are possible to two or more orders of magnitude. The difference in values for an increment of 0.1 latitude are 0.099, 0.100, or 0.101 units so that interpolations may be made to sufficient accuracy by adopting a constant difference of 0.100 units. Thus reading the tables becomes very simple. For example, to find the seismological co-latitude corresponding to 65. 0 316 north latitude enter the northern hemisphere table (Table 1) at 65. 0 3 and read 25.862. The remaining digits beyond the tenth-place (0.016) are subtracted from this value to give 25.846. In the southern hemisphere table (Table 2) digits beyond the tenths-place are added to the values read. The seismological co-latitude obtained in this way is accurate + or - 0.001 unit or approximately + or - 100 meters and, therefore, is well within the limits of accuracy for seismological calculations

What is the effect of a decision aid in potentially vulnerable parents? Insights from the head CT choice randomized trial.

ObjectiveTo test the hypotheses that use of the Head CT Choice decision aid would be similarly effective in all parent/patient dyads but parents with high (vs low) numeracy experience a greater increase in knowledge while those with low (vs high) health literacy experience a greater increase in trust.MethodsThis was a secondary analysis of a cluster randomized trial conducted at seven sites. One hundred seventy-two clinicians caring for 971 children at intermediate risk for clinically important traumatic brain injuries were randomized to shared decision making facilitated by the DA (n = 493) or to usual care (n = 478). We assessed for subgroup effects based on patient and parent characteristics, including socioeconomic status (health literacy, numeracy and income). We tested for interactions using regression models with indicators for arm assignment and study site.ResultsThe decision aid did not increase knowledge more in parents with high numeracy (P for interaction [Pint ] = 0.14) or physician trust more in parents with low health literacy (Pint  = 0.34). The decision aid decreased decisional conflict more in non-white parents (decisional conflict scale, -8.14, 95% CI: -12.33 to -3.95; Pint  = 0.05) and increased physician trust more in socioeconomically disadvantaged parents (trust in physician scale, OR: 8.59, 95% CI: 2.35-14.83; Pint  = 0.04).ConclusionsUse of the Head CT Choice decision aid resulted in less decisional conflict in non-white parents and greater physician trust in socioeconomically disadvantaged parents. Decision aids may be particularly effective in potentially vulnerable parents

Effectiveness of the head CT choice decision aid in parents of children with minor head trauma: study protocol for a multicenter randomized trial

Background: Blunt head trauma is a common cause of death and disability in children worldwide. Cranial computed tomography (CT), the reference standard for the diagnosis of traumatic brain injury (TBI), exposes children to ionizing radiation which has been linked to the development of brain tumors, leukemia, and other cancers. We describe the methods used to develop and test the effectiveness of a decision aid to facilitate shared decision-making with parents regarding whether to obtain a head CT scan or to further observe their child at home. Methods/Design: This is a protocol for a multicenter clinician-level parallel randomized trial to compare an intervention group receiving a decision aid, ‘Head CT Choice’, to a control group receiving usual care. The trial will be conducted at five diverse emergency departments (EDs) in Minnesota and California. Clinicians will be randomized to decision aid or usual care. Parents visiting the ED with children who are less than 18-years-old, have experienced blunt head trauma within 24 hours, and have one or two risk factors for clinically-important TBI (ciTBI) from the Pediatric Emergency Care Applied Research Network head injury clinical prediction rules will be eligible for enrollment. We will measure the effect of Head CT Choice on: (1) parent knowledge regarding their child’s risk of ciTBI, the available diagnostic options, and the risks of radiation exposure associated with a cranial CT scan (primary outcome); (2) parent engagement in the decision-making process; (3) the degree of conflict parents experience related to feeling uninformed; (4) patient and clinician satisfaction with the decision made; (5) the rate of ciTBI at seven days; (6) the proportion of patients in whom a cranial CT scan is obtained; and (7) seven-day healthcare utilization. To capture these outcomes, we will administer parent and clinician surveys immediately after each clinical encounter, obtain video recordings of parent-clinician discussions, administer parent healthcare utilization diaries, analyze hospital billing records, review the electronic medical record, and conduct telephone follow-up. Discussion: This multicenter trial will robustly assess the effectiveness of a decision aid on patient-centered outcomes, safety, and healthcare utilization in parents of children with minor head trauma in five diverse EDs. Trial registration: ClinicalTrials.gov registration number: NCT02063087. Registration date February 13, 2014

Estimating Fixed Effects: Perfect Prediction and Bias in Binary Response Panel Models, with an Application to the Hospital Readmissions Reduction Program

The maximum likelihood estimator for the regression coefficients, β, in a panel binary response model with fixed effects can be severely biased if N is large and T is small, a consequence of the incidental parameters problem. This has led to the development of conditional maximum likelihood estimators and, more recently, to estimators that remove the O(T–1) bias in β^. We add to this literature in two important ways. First, we focus on estimation of the fixed effects proper, as these have become increasingly important in applied work. Second, we build on a bias-reduction approach originally developed by Kosmidis and Firth (2009) for cross-section data, and show that in contrast to other proposals, the new estimator ensures finiteness of the fixed effects even in the absence of within-unit variation in the outcome. Results from a simulation study document favourable small sample properties. In an application to hospital data on patient readmission rates under the 2010 Affo

Natural gas production problems : solutions, methodologies, and modeling.

Natural gas is a clean fuel that will be the most important domestic energy resource for the first half the 21st centtuy. Ensuring a stable supply is essential for our national energy security. The research we have undertaken will maximize the extractable volume of gas while minimizing the environmental impact of surface disturbances associated with drilling and production. This report describes a methodology for comprehensive evaluation and modeling of the total gas system within a basin focusing on problematic horizontal fluid flow variability. This has been accomplished through extensive use of geophysical, core (rock sample) and outcrop data to interpret and predict directional flow and production trends. Side benefits include reduced environmental impact of drilling due to reduced number of required wells for resource extraction. These results have been accomplished through a cooperative and integrated systems approach involving industry, government, academia and a multi-organizational team within Sandia National Laboratories. Industry has provided essential in-kind support to this project in the forms of extensive core data, production data, maps, seismic data, production analyses, engineering studies, plus equipment and staff for obtaining geophysical data. This approach provides innovative ideas and technologies to bring new resources to market and to reduce the overall environmental impact of drilling. More importantly, the products of this research are not be location specific but can be extended to other areas of gas production throughout the Rocky Mountain area. Thus this project is designed to solve problems associated with natural gas production at developing sites, or at old sites under redevelopment

Barbarians at the British Museum: Anglo-Saxon Art, Race and Religion

A critical historiographical overview of art historical approaches to early medieval material culture, with a focus on the British Museum collections and their connections to religion

Tables of Seismological Co-latitude

The use of seismological latitude increases the accuracy of computations of great-circle distances and greatly simplifies the ellipticity correction for seismic travel-times. Bullen (1937b, p. 162) shows that the use of seismological latitude allows computations of travel-times with errors less than 0.1 second without recourse to the awkward triple-entry tables needed for complete ellipticity corrections (Bullen, 1937a). The tables in this paper permit conversion of the geographic latitude to seismological co-latitude. The tables are entered by reading the geographic latitude to the nearest unit down the lefthand column and the nearest tenth across the page. Interpolations are possible to two or more orders of magnitude. The difference in values for an increment of 0.1 latitude are 0.099, 0.100, or 0.101 units so that interpolations may be made to sufficient accuracy by adopting a constant difference of 0.100 units. Thus reading the tables becomes very simple. For example, to find the seismological co-latitude corresponding to 65. 0 316 north latitude enter the northern hemisphere table (Table 1) at 65. 0 3 and read 25.862. The remaining digits beyond the tenth-place (0.016) are subtracted from this value to give 25.846. In the southern hemisphere table (Table 2) digits beyond the tenths-place are added to the values read. The seismological co-latitude obtained in this way is accurate + or - 0.001 unit or approximately + or - 100 meters and, therefore, is well within the limits of accuracy for seismological calculations