Crustal rheology of the Himalaya and Southern Tibet inferred from magnetotelluric data.

The Cenozoic collision between the Indian and Asian continents formed the Tibetan plateau, beginning about 70 million years ago. Since this time, at least 1,400 km of convergence has been accommodated by a combination of underthrusting of Indian and Asian lithosphere, crustal shortening, horizontal extrusion and lithospheric delamination. Rocks exposed in the Himalaya show evidence of crustal melting and are thought to have been exhumed by rapid erosion and climatically forced crustal flow. Magnetotelluric data can be used to image subsurface electrical resistivity, a parameter sensitive to the presence of interconnected fluids in the host rock matrix, even at low volume fractions. Here we present magnetotelluric data from the Tibetan-Himalayan orogen from 77 degrees E to 92 degrees E, which show that low resistivity, interpreted as a partially molten layer, is present along at least 1,000 km of the southern margin of the Tibetan plateau. The inferred low viscosity of this layer is consistent with the development of climatically forced crustal flow in Southern Tibet.

Immigration status, acculturation, and dating violence risk for Hispanic adolescent girls in New Mexico.

Little data exist on dating violence experienced by immigrant Hispanic adolescents. The present study examined the relationships between immigration status, language spoken at home, and dating violence experienced by Hispanic adolescent girls in New Mexico. Data from the 2007 New Mexico Youth Risk and Resiliency Surveys were analyzed. Adjusted logistic regression analyses were conducted among the full sample of Hispanic females (N = 3,412) and among strata based on immigration status. Immigrant Hispanic girls were as likely as non-immigrant Hispanic girls to have experienced dating violence in the prior year (P = 0.93). Among immigrant Hispanic girls, those who were Non-English-dominant were one-fourth as likely to have experienced dating violence as those immigrant girls who were English-dominant (aOR 0.27 [95% CI 0.08-0.87]). Among US-born Hispanic girls, those who were Non-English-dominant were less likely to have experienced dating violence; however, this value did not reach statistical significance (aOR 0.65 [95% CI 0.33-1.27]). Past sexual experience was a significant risk factor for dating violence for US-born Hispanic girls (aOR 4.99 [95% CI 3.18-7.83]) but not for immigrant Hispanic girls (aOR 1.66 [95% CI 0.63-4.43]). Immigrant status was not found to be protective against dating violence for New Mexico Hispanic girls. However, those immigrant girls who were less acculturated in terms of language used at home were found to have only a quarter of the risk of dating violence as those more acculturated. The use of heritage language by immigrant Hispanic girls may be a protective factor against dating violence. Further studies are indicated to confirm this finding.

Low electrical resistivity associated with plunging of the Nazca flat slab beneath Argentina.

Beneath much of the Andes, oceanic lithosphere descends eastward into the mantle at an angle of about 30 degrees (ref. 1). A partially molten region is thought to form in a wedge between this descending slab and the overlying continental lithosphere as volatiles given off by the slab lower the melting temperature of mantle material. This wedge is the ultimate source for magma erupted at the active volcanoes that characterize the Andean margin. But between 28 degrees and 33 degrees S the subducted Nazca plate appears to be anomalously buoyant, as it levels out at about 100 km depth and extends nearly horizontally under the continent. Above this 'flat slab', volcanic activity in the main Andean Cordillera terminated about 9 million years ago as the flattening slab presumably squeezed out the mantle wedge. But it is unknown where slab volatiles go once this happens, and why the flat slab finally rolls over to descend steeply into the mantle 600 km further eastward. Here we present results from a magnetotelluric profile in central Argentina, from which we infer enhanced electrical conductivity along the eastern side of the plunging slab, indicative of the presence of partial melt. This conductivity structure may imply that partial melting occurs to at least 250 km and perhaps to more than 400 km depth, or that melt is supplied from the 410 km discontinuity, consistent with the transition-zone 'water-filter' model of Bercovici and Karato.

Appropriate utilization of semi-quantitative analysis in salivary scintigraphy.

AIM: The purpose of this case-control study was to determine whether semi-quantitative indices derived from salivary time-activity curves (TACs) are useful in the diagnosis and management of xerostomia. METHODS: Twenty-six healthy volunteers and 83 consecutive patients with xerostomia, including a subset of 40 patients with Sjogren's syndrome, underwent sequential salivary scintigraphy (SSS). Semi-quantitative analysis of the TACs was performed, deriving six different indices, previously cited in the literature, for each patient. These reflected trapping and uptake, stimulated excretion, or stimulated and unstimulated oral radioactivity. The indices were the percentage uptake, uptake ratios, maximum accumulation, pre-stimulatory oral radioactivity index, post-stimulatory oral radioactivity index and ejection fraction. RESULTS: Reduced parotid activity relative to submandibular activity, expressed as the P : S ratio, was able to distinguish abnormal from normal salivary function, and a parotid ejection fraction of greater than 50% also indicated normal parotid function. The other parameters showed no statistically significant difference between controls and patients. Individual variation in all indices served to widen the reference limits obtained from controls to the extent that they overlapped with those from the xerostomic population. CONCLUSIONS: This finding, together with previous work indicating that uptake parameters are only sensitive to differences exceeding 25% of the gland mass, the possibility that xerostomia may result from qualitative as well as quantitative changes in saliva and the probability that immune factors decrease neurosecretory circuits without affecting acinar mass, suggest that those indices derived from salivary TACs that directly reflect trapping and uptake are not useful in the detection of salivary gland disease.

Improving developmental screening among pediatricians in New Mexico: findings from the developmental screening initiative.

BACKGROUND: Seven pediatric primary care practices participated in New Mexico's Developmental Screening Initiative in a year-long quality improvement project with the goal of implementing standardized developmental screening tools. METHODS: The initiative utilized a learning collaborative approach and the Model for Improvement to promote best practice about developmental screening outlined by the American Academy of Pediatrics. Also, the project emphasized interagency collaboration to improve communication between medical providers and state and community agencies that provide services to children with developmental delays. RESULTS: A total of 1139 medical records were reviewed by the 7 practices, at 5 intervals during the intervention. At baseline, there were dramatic differences among the practices, with some not engaged in screening at all. Overall, the use of standardized developmental screening increased from 27% at baseline to 92% at the end of the project.

Clinical quality improvement for identification and management of overweight in pediatric primary care practices.

The purpose of the Pediatric Overweight Quality Improvement Initiative (POWQII) was to demonstrate the feasibility and value of simple interventions for improving pediatric care and to address the additional needs of overweight and obese children. Practices were recruited from around New Mexico, with 16 pediatricians completing the POWQII within 9 to 12 months. Initially, documentation of BMI percentile across all practices was only 49%, increasing to more than 90% on average following the first intervention and eventually reaching an average of 99%. Nutrition and physical activity counseling started at 52% and 39%, respectively, increasing to 87% for nutrition and 77% for physical activity. Diagnosis of POW patients improved over the course of the POWQII (67% to 94%). This intervention's potential impact can extend to a larger population of patients, resulting in twice as many receiving screening for POW and increasing best practices known to improve ongoing care and patient outcomes.

Quality improvement initiative in school-based health centers across new Mexico.

BACKGROUND: Quality improvement principles have been applied extensively to health care organizations, but implementation of quality improvement methods in school-based health centers (SBHCs) remains in a developmental stage with demonstration projects under way in individual states and nationally. Rural areas, such as New Mexico, benefit from the use of distance education techniques to reach providers throughout the state. METHODS: The Envision New Mexico (ENM) Quality Improvement Initiative involves training in quality improvement concepts and methods, identification of best practices for selected clinical services, and repeated use of data to measure changes leading to improvement. The ENM employs the Model for Improvement and the "Plan-Do-Study-Act" tool, which enables providers to self-evaluate, set goals, and assess results with their own data. RESULTS: Providers tend to overestimate their use of best practices. Contrasting these perceptions with findings from medical record reviews can provide impetus and focus for quality improvement through changes in specific clinical practices and management systems. Preliminary findings from New Mexico suggest that quality improvement interventions can be effective, with initial improvements over baseline reviews typically in the 20-40% range. CONCLUSION: Systematic efforts to enhance the quality of care can help improve both the effectiveness and efficiency of SBHCs, and provide evidence of the value of the care provided. Simple, efficient quality improvement techniques, with the use of distance learning technologies, can help achieve the full promise of expanded school-based health care.

Esophageal dysfunction in patients with atypical chest pain investigated with esophageal scintigraphy and myocardial perfusion imaging: an outcome study.

BACKGROUND: The objectives of this study were to determine the role of esophageal scintigraphy (ES) and myocardial perfusion imaging (MPI) in patients with atypical chest pain investigated for ischemic heart disease (IHD). METHODS AND RESULTS: One hundred five consecutive patients with atypical chest pain were investigated by dual-isotope MPI (1-day rest-stress protocol). Within a 10-day period, each patient also had liquid and semisolid ES performed with dynamic imaging over a 2-minute period for each phase. All patients were risk-stratified, and 28 patients were also investigated by coronary angiography. Patient outcome was assessed with the use of endpoints including cardiac death, myocardial infarction, and coronary revascularization procedures. Of the patients, 53 (50%) had esophageal dysfunction (ED) but no IHD, 41 (39%) had both ED and IHD, 5 (5%) had normal ES and IHD, and 6 (6%) had neither ED nor IHD. On the basis of outcome findings (n = 105) and coronary angiogram results (n = 28), MPI showed sensitivity for the detection of IHD of 92% in this patient population. Of the 94 patients (89%) with ED, 48 (51%) showed esophageal dysmotility, 9 (10%) showed gastroesophageal reflux, 17 (18%) showed esophageal spasm and dysmotility, 17 (18%) showed both reflux and dysmotility, and 3 showed other abnormalities. The median follow-up period after MPI was 20 months (range, 9-30 months). Twenty-one patients had cardiac events. These included 2 cardiac deaths, 2 myocardial infarctions, 6 coronary artery bypass graft surgeries, and 11 angioplasty/stent procedures. All but 2 of these patients had abnormal ES studies, and 7 had no prior history of IHD. MPI detected IHD in all but 2 of these patients. CONCLUSIONS: There is a high incidence of ED in patients with atypical chest pain referred for cardiologic assessment. The low proportion of patients with IHD alone and of those with neither IHD nor ED presenting with atypical chest pain (5%), as well as the high proportion with ED alone (50%), indicates the high likelihood of chest pain derived from ED. However, of the 21 patients with cardiac events, 7 had no prior history of IHD, indicating the importance of the use of MPI in the investigation of patients with atypical chest pain syndromes.