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The science of studying diamond inclusions for understanding Earth history has developed significantly over the past decades, with new instrumentation and techniques applied to diamond sample archives revealing the stories contained within diamond inclusions. This chapter reviews what diamonds can tell us about the deep carbon cycle over the course of Earth’s history. It reviews how the geochemistry of diamonds and their inclusions inform us about the deep carbon cycle, the origin of the diamonds in Earth’s mantle, and the evolution of diamonds through time.
Introduction: Simulation has assumed an integral role in the Canadian healthcare system with applications in quality improvement, systems development, and medical education. High quality simulation-based research (SBR) is required to ensure the effective and efficient use of this tool. This study sought to establish national SBR priorities and describe the barriers and facilitators of SBR in Emergency Medicine (EM) in Canada. Methods: Simulation leads (SLs) from all fourteen Canadian Departments or Divisions of EM associated with an adult FRCP-EM training program were invited to participate in three surveys and a final consensus meeting. The first survey documented active EM SBR projects. Rounds two and three established and ranked priorities for SBR and identified the perceived barriers and facilitators to SBR at each site. Surveys were completed by SLs at each participating institution, and priority research themes were reviewed by senior faculty for broad input and review. Results: Twenty SLs representing all 14 invited institutions participated in all three rounds of the study. 60 active SBR projects were identified, an average of 4.3 per institution (range 0-17). 49 priorities for SBR in Canada were defined and summarized into seven priority research themes. An additional theme was identified by the senior reviewing faculty. 41 barriers and 34 facilitators of SBR were identified and grouped by theme. Fourteen SLs representing 12 institutions attended the consensus meeting and vetted the final list of eight priority research themes for SBR in Canada: simulation in CBME, simulation for interdisciplinary and inter-professional learning, simulation for summative assessment, simulation for continuing professional development, national curricular development, best practices in simulation-based education, simulation-based education outcomes, and simulation as an investigative methodology. Conclusion: Conclusion: This study has summarized the current SBR activity in EM in Canada, as well as its perceived barriers and facilitators. We also provide a consensus on priority research themes in SBR in EM from the perspective of Canadian simulation leaders. This group of SLs has formed a national simulation-based research group which aims to address these identified priorities with multicenter collaborative studies.
Objectives: To test the hypothesis that brain arterial diameters are associated with cognitive performance, particularly in arteries supplying domain-specific territories. Methods: Stroke-free participants in the Northern Manhattan Study were invited to have a brain MRI from 2003–2008. The luminal diameters of 13 intracranial arterial segments were obtained using time-of-flight magnetic resonance angiogram (MRA), and then averaged and normalized into a global score and region-specific arterial diameters. Z-Scores for executive function, semantic memory, episodic memory and processing speed were obtained at MRI and during follow-up. Adjusted generalized additive models were used to assess for associations. Results: Among the 1034 participants with neurocognitive testing and brain MRI, there were non-linear relationships between left anterior (ACA) and middle cerebral artery (MCA) diameter and semantic memory Z-scores (χ2=10.00; DF=3; p=.019), and left posterior cerebral artery (PCA) and posterior communicating artery (Pcomm) mean diameter and episodic memory Z-scores (χ2=9.88; DF=3; p=.020). Among the 745 participants who returned for 2nd neuropsychological testing, on average 5.0±0.4 years after their MRI, semantic memory change was associated non-linearly with the left PCA/Pcomm mean diameter (χ2=13.09; DF=3; p=.004) and with the right MCA/ACA mean diameter (χ2=8.43; DF=3; p=.03). In both cross-sectional and longitudinal analyses, participants with the larger brain arterial diameters had more consistently lower Z-scores and greater decline than the rest of the participants. Conclusions: Brain arterial diameters may have downstream effects in brain function presenting as poorer cognition. Identifying the mechanisms and the directionality of such interactions may increase the understanding of the vascular contribution to cognitive impairment and dementia. (JINS, 2018, 24, 335–346)
A previous small study suggested that Brain Network Activation (BNA), a novel ERP-based brain network analysis, may have diagnostic utility in attention deficit hyperactivity disorder (ADHD). In this study we examined the diagnostic capability of a new advanced version of the BNA methodology on a larger population of adults with and without ADHD.
Subjects were unmedicated right-handed 18- to 55-year-old adults of both sexes with and without a DSM-IV diagnosis of ADHD. We collected EEG while the subjects were performing a response inhibition task (Go/NoGo) and then applied a spatio-temporal Brain Network Activation (BNA) analysis of the EEG data. This analysis produced a display of qualitative measures of brain states (BNA scores) providing information on cortical connectivity. This complex set of scores was then fed into a machine learning algorithm.
The BNA analysis of the EEG data recorded during the Go/NoGo task demonstrated a high discriminative capacity between ADHD patients and controls (AUC = 0.92, specificity = 0.95, sensitivity = 0.86 for the Go condition; AUC = 0.84, specificity = 0.91, sensitivity = 0.76 for the NoGo condition).
BNA methodology can help differentiate between ADHD and healthy controls based on functional brain connectivity. The data support the utility of the tool to augment clinical examinations by objective evaluation of electrophysiological changes associated with ADHD. Results also support a network-based approach to the study of ADHD.
This article uses census microdata to address key issues in the Mexican immigration debate. First, we find striking parallels in the experiences of older and newer immigrant groups with substantial progress among second- and subsequent-generation immigrants from southern and eastern Europe and Mexican Americans. Second, we contradict a view of immigrant history that contends that early–twentieth–century immigrants from southern and eastern Europe found well–paying jobs in manufacturing that facilitated their ascent into the middle class. Both first and second generations remained predominantly working class until after World War II. Third, the erosion of the institutions that advanced earlier immigrant generations is harming the prospects of Mexican Americans. Fourth, the mobility experience of earlier immigrants and of Mexicans and Mexican Americans differed by gender, with a gender gap opening among Mexican Americans as women pioneered the path to white–collar and professional work. Fifth, public–sector and publicly funded employment has proved crucial to upward mobility, especially among women. The reliance on public employment, as contrasted to entrepreneurship, has been one factor setting the Mexican and African American experience apart from the economic history of most southern and eastern European groups as well as from the experiences of some other immigrant groups today.
The high rate of population turnover in nineteenth-century North American cities no longer requires emphasis. However, students of historical migration have progressed very little beyond merely documenting its existence. As a result, the relationship of social, economic, and demographic factors to migration remains imperfectly understood, and the extent to which rates of population movement varied with economic growth, population size, or other factors still is a matter of conjecture.
In another essay, we began the systematic exploration of population movement through an analysis of patterns in Buffalo and rural Erie County, New York, in 1855. The 1855 New York state census recorded how long each individual had lived in the place in which he or she was enumerated. Using this information, and correcting for mortality, we developed estimates of population persistence and of the determinants of length of residence, which are two conceptually distinct phenomena. We compared both to patterns in Hamilton, Ontario, during the same period and, less systematically, to what historians reported for other places. We concluded that the rate of population persistence in Buffalo was higher than in a number of other cities, and we attributed the difference to the dynamism of the city’s economic life, compared especially to Hamilton in the same years. Nonetheless, despite differences in rates of persistence, the social and demographic correlates of length of residence were strikingly similar in each city and in the countryside as well.
Suicide is a devastating public health problem and very few biological treatments have been found to be effective for quickly reducing the intensity of suicidal ideation (SI). We have previously shown that a single dose of ketamine, a glutamate N-methyl-d-aspartate (NMDA) receptor antagonist, is associated with a rapid reduction in depressive symptom severity and SI in patients with treatment-resistant depression.
We conducted a randomized, controlled trial of ketamine in patients with mood and anxiety spectrum disorders who presented with clinically significant SI (n = 24). Patients received a single infusion of ketamine or midazolam (as an active placebo) in addition to standard of care. SI measured using the Beck Scale for Suicidal Ideation (BSI) 24 h post-treatment represented the primary outcome. Secondary outcomes included the Montgomery–Asberg Depression Rating Scale – Suicidal Ideation (MADRS-SI) score at 24 h and additional measures beyond the 24-h time-point.
The intervention was well tolerated and no dropouts occurred during the primary 7-day assessment period. BSI score was not different between the treatment groups at 24 h (p = 0.32); however, a significant difference emerged at 48 h (p = 0.047). MADRS-SI score was lower in the ketamine group compared to midazolam group at 24 h (p = 0.05). The treatment effect was no longer significant at the end of the 7-day assessment period.
The current findings provide initial support for the safety and tolerability of ketamine as an intervention for SI in patients who are at elevated risk for suicidal behavior. Larger, well-powered studies are warranted.
Metabolic syndrome (MetS) is a clustering of vascular risk factors and is associated with increased risk of cardiovascular disease. Less is known about the relationship between MetS and cognition. We examined component vascular risk factors of MetS as correlates of different cognitive domains. The Northern Manhattan Study (NOMAS) includes 1290 stroke-free participants from a largely Hispanic multi-ethnic urban community. We used structural equation modeling (SEM) to model latent variables of MetS, assessed at baseline and an average of 10 years later, at which time participants also underwent a full cognitive battery. The two four-factor models, of the metabolic syndrome (blood pressure, lipid levels, obesity, and fasting glucose) and of cognition (language, executive function, psychomotor, and memory), were each well supported (CFI=0.97 and CFI=0.95, respectively). When the two models were combined, the correlation between metabolic syndrome and cognition was −.31. Among the metabolic syndrome components, only blood pressure uniquely predicted all four cognitive domains. After adjusting for age, gender, race/ethnicity, education, smoking, alcohol, and risk factor treatment variables, blood pressure remained a significant correlate of all domains except memory. In this stroke-free race/ethnically diverse community-based cohort, MetS was associated with cognitive function suggesting that MetS and its components may be important predictors of cognitive outcomes. After adjusting for sociodemographic and vascular risk factors, blood pressure was the strongest correlate of cognitive performance. Findings suggest MetS, and in particular blood pressure, may represent markers of vascular or neurodegenerative damage in aging populations. (JINS, 2014, 20, 1–10)
Material analysis is a basic task of archaeometry, but it is problematic in many ways: the analysis should be representative but should not destroy or damage the object: the analysis should be rapid and inexpensive in order to enable the study of large quantities of objects for statistical evaluation. Analyses based upon small subsamples tend to give random results, i.e. results not representative for the entire specimen, but analyses of the entire body should be truly non-destructive.
EDS-XFA (energy dispersive X-ray fluorescence analysis) is one of the few non-destructive analytical tools giving chemical information on the average composition of a surface. Nearly 90% of all natural chemical elements can be detected provided they are present as major or minor constituents. Like all instrumental techniques, EDS-XFA is based upon a comparison of unknown samples with standards of known composition (for details see Bertin, 1978); quantitative analysis is possible when surface conditions (size, morphology, texture, etc.) of unknowns and standards are identical. Regarding archaeological objects, the sample surface should not be treated, smoothed or flattened, but has to be left in its original morphology (which varies from specimen to specimen) and this may influence the analytical results. These are therefore considered to be qualitative and are essentially used to establish groups of similar chemical composition (Fig. 1). This chemical classification, when applied to cylinder seals, is closely associated with mineral/rock species since a clear interdependence exists between mineral species and their composition. The mineralogical classification, however, is, by tradition, based upon physical properties of minerals like optics, hardness, etc., and not primarily on their chemistry.
The theory of cognitive reserve attempts to explain why some individuals are more resilient to age-related brain pathology. Efforts to explore reserve have been hindered by measurement difficulties. Reed et al. (2010) proposed quantifying reserve as residual variance in episodic memory performance that remains after accounting for demographic factors and brain pathology (whole brain, hippocampal, and white matter hyperintensity volumes). This residual variance represents the discrepancy between an individual's predicted and actual memory performance. The goals of the present study were to extend these methods to a larger, community-based sample and to investigate whether the residual reserve variable is explained by age, predicts longitudinal changes in language, and predicts dementia conversion independent of age. Results support this operational measure of reserve. The residual reserve variable was associated with higher reading ability, lower likelihood of meeting criteria for mild cognitive impairment, lower odds of dementia conversion independent of age, and less decline in language abilities over 3 years. Finally, the residual reserve variable moderated the negative impact of memory variance explained by brain pathology on language decline. This method has the potential to facilitate research on the mechanisms of cognitive reserve and the efficacy of interventions designed to impart reserve. (JINS, 2013, 19, 1–9)
NASA's NuSTAR observatory is the first focusing hard X-ray telescope. Launched in June 2012, NuSTAR is sensitive in the 3–79 keV range with unprecedented ~17″ FWHM angular resolution above 12 keV, a result of its multilayer-coated optics and 10-m focal length. With its large effective area (900 cm2 at 10 keV), NuSTAR has point-source sensitivity ~100 times better than previous hard X-ray telescopes. Here we describe NuSTAR and its planned work on rotation-powered pulsars and magnetars during its nominal 2-yr baseline mission that has just commenced.
The meanings of several target neuropsychological variables, including measures of executive functioning, were examined using contextual analysis across a sample of English-speakers and a sample of Spanish-speakers. Results of the contextual analysis, which examined the contributions of the latent constructs of memory, psychomotor speed, visual spatial ability, and knowledge and comprehension, to the target neuropsychological variables indicate that each of the target variables likely reflects the unique contribution of several reference abilities. These findings provide evidence that the neuropsychological variables are multi-dimensional. The patterns of relations were similar across the samples of English and Spanish speakers. (JINS, 2012, 18, 223–233)