Effect of Combination Folic Acid, Vitamin B6 , and Vitamin B12 Supplementation on Fracture Risk in Women: A Randomized, Controlled Trial.

Epidemiologic studies have demonstrated an association of elevated plasma homocysteine levels with greater bone resorption and fracture risk. Vitamins B12 , B6 , and folic acid are cofactors in homocysteine metabolism, and supplementation with B vitamins is effective in lowering homocysteine levels in humans. However, randomized trials of supplemental B vitamins for reduction of fracture risk have been limited. Therefore, we performed an ancillary study to the Women's Antioxidant and Folic Acid Cardiovascular Study (WAFACS), a large randomized trial of women with preexisting cardiovascular disease or three or more coronary risk factors, to test whether a daily B vitamin intervention including folic acid (2.5 mg/day), vitamin B6 (50 mg/day), and vitamin B12 (1 mg/day) reduces nonspine fracture risk over 7.3 years of treatment and follow-up. Among 4810 women, we confirmed 349 nonspine fracture cases by centralized review of medical records. In a substudy of 300 women (150 in treatment group and 150 controls) with paired plasma samples at randomization and follow-up (7.3 years later), we measured two bone turnover markers, including C-terminal cross-linking telopeptide of type I collagen (CTX) and intact type I procollagen N-propeptide (P1NP). In Cox proportional hazards models based on intention-to-treat, we found no significant effects of B vitamin supplementation on nonspine fracture risk (relative hazard = 1.08; 95% confidence interval, 0.88 to 1.34). In a nested case-cohort analysis, there were no significant effects of B vitamins on fracture risk among women with elevated plasma homocysteine levels, or low levels of vitamins B12 or B6 , or folate at baseline. Furthermore, treatment with B vitamins had no effect on change in markers of bone turnover. We found no evidence that daily supplementation with B vitamins reduces fracture risk or rates of bone metabolism in middle-aged and older women at high risk of cardiovascular disease. © 2017 American Society for Bone and Mineral Research

Multitemporal Snow Cover Mapping in Mountainous Terrain for Landsat Climate Data Record Development

A multitemporal method to map snow cover in mountainous terrain is proposed to guide Landsat climate data record (CDR) development. The Landsat image archive including MSS, TM, and ETM+ imagery was used to construct a prototype Landsat snow cover CDR for the interior northwestern United States. Landsat snow cover CDRs are designed to capture snow-covered area (SCA) variability at discrete bi-monthly intervals that correspond to ground-based snow telemetry (SNOTEL) snow-water-equivalent (SWE) measurements. The June 1 bi-monthly interval was selected for initial CDR development, and was based on peak snowmelt timing for this mountainous region. Fifty-four Landsat images from 1975 to 2011 were preprocessed that included image registration, top-of-the-atmosphere (TOA) reflectance conversion, cloud and shadow masking, and topographic normalization. Snow covered pixels were retrieved using the normalized difference snow index (NDSI) and unsupervised classification, and pixels having greater (less) than 50% snow cover were classified presence (absence). A normalized SCA equation was derived to independently estimate SCA given missing image coverage and cloud-shadow contamination. Relative frequency maps of missing pixels were assembled to assess whether systematic biases were embedded within this Landsat CDR. Our results suggest that it is possible to confidently estimate historical bi-monthly SCA from partially cloudy Landsat images. This multitemporal method is intended to guide Landsat CDR development for freshwaterscarce regions of the western US to monitor climate-driven changes in mountain snowpack extent

An Agent-based Model of Housing Search and Intraurban Migration in the Twin Cities of Minnesota

Intraurban migration defines many neighbourhood dynamics and consequentlyimpacts land use patterns in the long term. Housing location decision-making is a complexprocess involving many features of the housing market that interact with the perceptions ofhome searchers. Although modellers have paid much attention to the prices and utilities ofthe environmental, ecological, and public services associated with housing, the housingsearch process is neglected in many agent-based land use models involving urban housingmarket. The challenge of incorporating housing search partially lies in the prohibitive costof identifying, recording, and quantifying housing search activities at a large scale. Thispaper presents an agent-based model of intraurban migration featuring straightforward yetempirically accurate rules for housing search. Drawing on intervening opportunity andintraurban migration theories, this model is specified and calibrated using real-worldhousing vacancies and relocation origin-destination pairs extracted from parcel recordsavailable in the Twin Cities for 2005 to 2007. Multiple validation methods, including innermigration rates, Syrjala tests, and minimum spanning tree comparisons, show that thesearch rules based on housing vacancy distribution and negative exponential distance-decayprobability can satisfactorily simulate the pattern of the housing search and locationalchoices made by homeowners in the Twin Cities of Minnesota

Inner-shell photodetachment of na-using r-matrix methods

Inner-shell photodetachment of Na-near the L-edge threshold was investigated using the R-matrix method. Significant structure was found in the cross section, and this structure is shown to be related to the complicated correlated electron dynamics endemic in negative ions. Comparison with experiment suggests that the absolute values of the measured cross section might be too small by a factor of two. © 2020 by the authors

Prospective Associations of Coronary Heart Disease Loci in African Americans Using the MetaboChip: The PAGE Study

Background: Coronary heart disease (CHD) is a leading cause of morbidity and mortality in African Americans. However, there is a paucity of studies assessing genetic determinants of CHD in African Americans. We examined the association of published variants in CHD loci with incident CHD, attempted to fine map these loci, and characterize novel variants influencing CHD risk in African Americans. Methods and Results: Up to 8,201 African Americans (including 546 first CHD events) were genotyped using the MetaboChip array in the Atherosclerosis Risk in Communities (ARIC) study and Women's Health Initiative (WHI). We tested associations using Cox proportional hazard models in sex- and study-stratified analyses and combined results using meta-analysis. Among 44 validated CHD loci available in the array, we replicated and fine-mapped the SORT1 locus, and showed same direction of effects as reported in studies of individuals of European ancestry for SNPs in 22 additional published loci. We also identified a SNP achieving array wide significance (MYC: rs2070583, allele frequency 0.02, P = 8.1×10−8), but the association did not replicate in an additional 8,059 African Americans (577 events) from the WHI, HealthABC and GeneSTAR studies, and in a meta-analysis of 5 cohort studies of European ancestry (24,024 individuals including 1,570 cases of MI and 2,406 cases of CHD) from the CHARGE Consortium. Conclusions: Our findings suggest that some CHD loci previously identified in individuals of European ancestry may be relevant to incident CHD in African Americans

Prospective associations of coronary heart disease loci in African Americans using the MetaboChip

Background: Coronary heart disease (CHD) is a leading cause of morbidity and mortality in African Americans. However, there is a paucity of studies assessing genetic determinants of CHD in African Americans. We examined the association of publishe

Illustrating a new 'conceptual design pattern' for agent-based models of land use via five case studies—the MR POTATOHEAD framework

This chapter presents a "conceptual design pattern" (CDP) that represents key elements of standard ABM/LUCC models in a comprehensive logical framework and includes basic functionality and data often present in ABM/LUCC models. The CDP illustrates the key building blocks for ABM/LUCC models, creating a template to assist scholars new to the field to understand existing models and design their own models. Second, the framework facilitates direct comparison of the structure and function of existing models. We present five separately developed models within this framework (SLUDGE, SOME, FEARLUS, LUCITA, and SYPRIA), demonstrating how multiple models can be represented and compared within the same meta-structure. The exercise highlights elements common to all models, demonstrates the unique contributions of each model, reveals commonalities between models, and highlights processes associated with land-use change that are not covered by our models. The CDP as presented here is very much a work in progress, and we welcome feedback from other ABM/LUCC developers, in the hopes of ultimately developing a shared model representation that will accelerate the development of not only ABM/LUCC, but also the theory of land-use change

The prevalence and correlates of texting while driving among a population-based sample of Ontario students

Objective: Texting while driving (TWD) has a deleterious impact on driving performance and may pose a significant challenge to traffic safety. This challenge may be particularly relevant for young and inexperienced drivers. This study examined the prevalence and risk factors of writing text messages or emails while driving during the past 12 months. Method: This study analyzed a subpopulation of 1,133 licensed students 16 years of age or older from the 2013 Ontario Student Drug Use Survey (OSDUHS), a population-based survey of students in Ontario, Canada. Results: Our results indicate that 36% of licensed drivers reported writing a text message while driving during the past 12 months; of those who did, 56% reported doing so 4 or more times. Graduated licensing was the strongest factor predicting TWD. Compared to students with the more restrictive G1 license, students with a G2 or full license were 9.4 times more likely to report TWD after controlling for the effect of all other factors. Older students, white students, and students attending school in urban centers were more likely to report TWD, and the amount of time spent on social media sites, being a passenger with a driver using substances, and past-year collisions were also significantly associated with TWD. Gender differences and participation in driver education training were not associated with TWD. Conclusions: This research demonstrates that TWD is an extremely common behavior among licensed student drivers in Ontario, particularly among those who have passed the first stage of graduated licensing. TWD is associated with other risky driving behaviors and outcomes, and the findings from this study underscore the need to better understand the harms associated with this behavior

Phonon-Induced Population Dynamics and Intersystem Crossing in Nitrogen-Vacancy Centers

We report direct measurement of population dynamics in the excited state manifold of a nitrogen-vacancy (NV) center in diamond. We quantify the phonon-induced mixing rate and demonstrate that it can be completely suppressed at low temperatures. Further, we measure the intersystem crossing (ISC) rate for different excited states and develop a theoretical model that unifies the phonon-induced mixing and ISC mechanisms. We find that our model is in excellent agreement with experiment and that it can be used to predict unknown elements of the NV center’s electronic structure. We discuss the model’s implications for enhancing the NV center’s performance as a room-temperature sensor.Physic