Emplacement of the Franklin large igneous province and initiation of the Sturtian Snowball Earth.

During the Cryogenian (720 to 635 Ma ago) Snowball Earth glaciations, ice extended to sea level near the equator. The cause of this catastrophic failure of Earth's thermostat has been unclear, but previous geochronology has suggested a rough coincidence of glacial onset with one of the largest magmatic episodes in the geological record, the Franklin large igneous province. U-Pb geochronology on zircon and baddeleyite from sills associated with the paleo-equatorial Franklin large igneous province in Arctic Canada record rapid emplacement between 719.86 ± 0.21 and 718.61 ± 0.30 Ma ago, 0.9 to 1.6 Ma before the onset of widespread glaciation. Geologic observations and (U-Th)/He dates on Franklin sills are compatible with major post-Franklin exhumation, possibly due to development of mafic volcanic highlands on windward equatorial Laurentia and increased global weatherability. After a transient magmatic CO2 flux, long-term carbon sequestration associated with increased weatherability could have nudged Earth over the threshold for runaway ice-albedo feedback.

Adeno-associated viral vector serotype 9-based gene replacement therapy for SURF1-related Leigh syndrome.

SURF1 (surfeit locus protein 1)-related Leigh syndrome is an early-onset neurodegenerative disorder, characterized by reduction in complex IV activity, resulting in disrupted mitochondrial function. Currently, there are no treatment options available. To test our hypothesis that adeno-associated viral vector serotype 9 (AAV9)/human SURF1 (hSURF1) gene replacement therapy can provide a potentially meaningful and long-term therapeutic benefit, we conducted preclinical efficacy studies using SURF1 knockout mice and safety evaluations with wild-type (WT) mice. Our data indicate that with a single intrathecal (i.t.) administration, our treatment partially and significantly rescued complex IV activity in all tissues tested, including liver, brain, and muscle. Accordingly, complex IV content (examined via MT-CO1 protein expression level) also increased with our treatment. In a separate group of mice, AAV9/hSURF1 mitigated the blood lactic acidosis induced by exhaustive exercise at 9 months post-dosing. A toxicity study in WT mice showed no adverse effects in either the in-life portion or after microscopic examination of major tissues up to a year following the same treatment regimen. Taken together, our data suggest a single dose, i.t. administration of AAV9/hSURF1 is safe and effective in improving biochemical abnormalities induced by SURF1 deficiency with potential applicability for SURF1-related Leigh syndrome patients.

A population-based cross-sectional study comparing depression and health service deficits between rural and nonrural U.S. military veterans.

With involvement in two wars over the past decade, there has been a documented increase in depression prevalence and suicide incidence among U.S. military veterans. Because higher proportions of veterans come from rural communities, access to care may be an issue when behavioral health care is needed. Although the Veterans Administration has expanded health services in rural areas, this has not always resulted in increased service utilization. This study examined the prevalence of depression and associated health service deficits (HSDs) for rural versus nonrural U.S. military veterans. Using bivariate and multivariate techniques, 2006 Behavioral Risk Factor Surveillance System data were analyzed. Bivariate analysis revealed that rural veterans had greater odds of having at least one HSD, being currently depressed as measured by the Personal Health Questionnaire-8, and having lifetime depression. Logistic regression analysis confirmed that rural veterans had higher odds of both current and lifetime depression than nonrural veterans when controlling for socioeconomic status and race/ethnicity. Additionally, logistic regression analysis also revealed that rural veterans with current depression had higher odds of being Hispanic or Other/Multiracial than Caucasian, not employed for wages than employed for wages, <65 years of age, and reported having at least one HSD.

Zircon dating of oceanic crustal accretion.

Most of Earth's present-day crust formed at mid-ocean ridges. High-precision uranium-lead dating of zircons in gabbros from the Vema Fracture Zone on the Mid-Atlantic Ridge reveals that the crust there grew in a highly regular pattern characterized by shallow melt delivery. Combined with results from previous dating studies, this finding suggests that two distinct modes of crustal accretion occur along slow-spreading ridges. Individual samples record a zircon date range of 90,000 to 235,000 years, which is interpreted to reflect the time scale of zircon crystallization in oceanic plutonic rocks.