Evolution of Water Reservoirs on Mars: Constraints from Hydrogen Isotopes in Martian Meteorites

Martian surface morphology implies that Mars was once warm enough to maintain persistent liquid water on its surface. While the high D/H ratios (~6 times the Earth's ocean water) of the current martian atmosphere suggest that significant water has been lost from the surface during martian history, the timing, processes, and the amount of the water loss have been poorly constrained. Recent technical developments of ion-microprobe analysis of martian meteorites have provided accurate estimation of hydrogen isotope compositions (D/H) of martian water reservoirs at the time when the meteorites formed. Based on the D/H data from the meteorites, this study demonstrates that the water loss during the pre-Noachian (>41-99 m global equivalent layers, GEL) was more significant than in the rest of martian history (>10-53 m GEL). Combining our results with geological and geomorphological evidence for ancient oceans, we propose that undetected subsurface water/ice (~100-1000 m GEL) should have existed, and it exceeds the observable present water inventory (~20-30 m GEL) on Mars.Comment: 29 pages, 4 figures, 2 tables, accepted for publication in Earth and Planetary Science Letter

Raloxifene Enhances Vertebral Mechanical Properties Independent of Bone Density

Anti-remodeling agents produce similar reductions in vertebral fracture risk despite large differences in BMD changes suggesting the mechanism of fracture risk reduction may differ among these agents. Forty-eight intact (non-ovariectomized) skeletally mature female beagle dogs were treated orally for 12 months with clinically relevant doses of risedronate (RIS, 0.10 mg/kg/day), alendronate (ALN, 0.2 mg/kg/day), raloxifene (RAL, 0.50 mg/kg/day), or saline (VEH, 1 ml/kg/day). After sacrifice, the following measurements were made on vertebral bone: areal (aBMD) and volumetric (vBMD) bone mineral densities, tissue mineralization by ash content, static and dynamic histomorphometric parameters, microdamage, and extrinsic and intrinsic measures of biomechanical strength, stiffness and energy to fracture. At these doses, RAL suppressed bone turnover (-20%) significantly less than the bisphosphonates (-66 and -71%) and did not produce significant differences in aBMD, vBMD, BV/TV or percent ash compared to VEH-treated animals. Microdamage accumulation in RAL-treated animals was not significantly different than VEH; both RIS and ALN had significantly higher crack surface density compared to VEH. Stiffness was significantly higher than VEH in all treatment groups. Ultimate load divided by aBMD, a measure of strength independent of BMD, was significantly higher only in RAL-treated animals compared to VEH (+16%, P = 0.015). Based on these data, we conclude that raloxifene produces improvements in bone mechanical properties in ways that do not involve increases in BMD.The authors thank Dr. Keith Condon, Diana Jacob, Mary Hooser, and Lauren Waugh for histological preparation and Dr. Charles Turner for his assistance with mechanical testing. This work was supported by NIH Grants 5R01AR047838-03 and 5T32AR007581-09 and research grants from The Alliance for Better Bone Health (Procter and Gamble Pharmaceuticals and sanofi-aventis), and Lilly Research Laboratories. Merck and Co. kindly provided the alendronate. This investigation utilized an animal facility constructed with support from Research Facilities Improvement Program Grant Number C06 RR10601-01 from the National Center for Research Resources, National Institutes of Health

Experiences and Perspectives of Clinical Supervisors in Cross-Cultural Supervision: The Impact of Supervisor Race and Ethnicity

This qualitative study explored experiences of racial and ethnic minority supervisors in cross-cultural supervision in the counseling related fields in the U.S. or Canada. Five supervisors from different countries of origin participated. Both their general experiences in supervision and the ways in which the racial and ethnic minority supervisors managed cultural discussions and the supervisors\u27 own needs were examined in supervision. The phenomenological study sought to describe the essence of the racial and ethnic minority supervisors in cross-cultural supervision and identified several themes grounded in their experiences: (a) distinct experiences as racial and ethnic minority supervisors; (b) managing diversity issues with cultural focus (challenging supervisees with diversity issues; using self-disclosure); (c) embracing the difference and its challenges (managing diversity issues universally; using a difference as a motivator and strength); (d) support and mentorship are critical to success. While there are some limitations, this study contributes to the growing body of literature about multicultural supervision and the approaches to improve the counselor education and training and the quality of clinical work. Finally, recommendations for supervision practice, counselor educators and trainers, and future research are discussed

Experiences and Perspectives of Clinical Supervisors in Cross-Cultural Supervision: The Impact of Supervisor Race and Ethnicity

This qualitative study explored experiences of racial and ethnic minority supervisors in cross-cultural supervision in the counseling related fields in the U.S. or Canada. Five supervisors from different countries of origin participated. Both their general experiences in supervision and the ways in which the racial and ethnic minority supervisors managed cultural discussions and the supervisors\u27 own needs were examined in supervision. The phenomenological study sought to describe the essence of the racial and ethnic minority supervisors in cross-cultural supervision and identified several themes grounded in their experiences: (a) distinct experiences as racial and ethnic minority supervisors; (b) managing diversity issues with cultural focus (challenging supervisees with diversity issues; using self-disclosure); (c) embracing the difference and its challenges (managing diversity issues universally; using a difference as a motivator and strength); (d) support and mentorship are critical to success. While there are some limitations, this study contributes to the growing body of literature about multicultural supervision and the approaches to improve the counselor education and training and the quality of clinical work. Finally, recommendations for supervision practice, counselor educators and trainers, and future research are discussed

Bilateral coronary ostial stenosis and aortic regurgitation in a patient with cardiovascular syphilis

AbstractCardiovascular syphilis is associated with the tertiary stage of syphilis infection; it involves the ascending aorta and can cause aortic aneurysm, aortic regurgitation, and coronary ostial stenosis. We report a surgical case of bilateral coronary ostial lesion and aortic regurgitation due to syphilitic aortitis.<Learning objective: Syphilitic aortitis involves the ascending aorta, resulting in aortic aneurysm, aortic regurgitation, and coronary ostial stenosis. Unlike atherosclerosis, coronary ostial stenosis is caused by aortic wall thickening, and coronary lesions distal to the ostia occur only rarely. After surgery, long-term follow up is mandatory as a result of aortic dilatation involving the sinuses of Valsalva, occurrence of prosthetic valve dehiscence, or graft failure caused by continuous infection of the aortic wall.