The Floor of the Arctic Ocean in Photographs

Over 2,000 usable bottom photographs have been taken in the western Arctic Ocean. The 87 stations cover the major geomorphic provinces of this part of the Arctic Basin, including the Alpha Cordillera, Mendeleyev Ridge, and Canada Abyssal Plain as well as smaller features. The ridge and plain provinces differ markedly in their bottom characteristics. Scattered rocks, living animals and indications of bottom current are most prevalent on the ridges. Trails are most abundant on the abyssal plains. The differences are attributed to bottom current distributions and turbidity currents. Bedrock outcrops were observed on the tops of two knolls on the Mendeleyev Ridge.Le fond de l'océan Arctique en photographies. Dans la partie occidentale de l'océan Arctique, on a pris plus de 2,000 clichés du fond sous-marin. Les 87 stations couvrent les principales provinces géomorphologiques de cette partie du bassin arctique et comprennent la cordillère Alpha, la dorsale de Mendéléev et la plaine abyssale canadienne, ainsi que des reliefs de moindre importance. Les dorsales et la plaine abyssale diffèrent beaucoup dans leurs caractéristiques de fond. Sur les dorsales, des roches éparpillées, des animaux vivants et des indices de courants de fond dominent. Dans la plaine abyssale, les pistes d'animaux mains sont abondantes. On attribue ces différences à la distribution des courants de fond et aux courants de turbidité. On a observé des affleurements du soubassement sur le sommet de deux monticules de la dorsale de Mendéléev

Comparison of Contact Kinematics in Posterior-Stabilized and Cruciate-Retaining Total Knee Arthroplasty at Long-Term Follow-Up

© 2019 Elsevier Inc. Background: There is controversy regarding the superiority of posterior-stabilizing (PS) total knee arthroplasty (TKA) and cruciate-retaining (CR) TKA. Substantial work has made comparisons between PS and CR TKA at follow-ups of less than 5 years. It was the goal of the present study to compare the kinematics at greater than 5 years postoperatively between CR and PS TKA, with a secondary goal of comparing patient function. Methods: A total of 42 knees were investigated, with equal representation in the PS and CR TKA groups. Patients underwent radiostereometric analysis imaging at 0°, 20°, 40°, 60° 80°, and 100° of flexion. Contact position, magnitude of excursion, and condylar separation on each condyle were measured. A Timed-Up-and-Go functional test was also performed by patients, with the total test time being measured. Preoperative and postoperative clinical outcome scores were also collected. Results: There were differences in contact position on both the medial and lateral condyles at multiple angles of flexion (P \u3c .05). There was no difference (P = .89) in medial excursion; however, PS TKA had greater lateral excursion than CR TKA (P \u3c .01). No difference (P \u3e .99) was found in frequency of condylar separation. PS TKA was associated with faster (P = .03) total Timed-Up-and-Go test times. There were no differences in clinical outcome scores between the groups preoperatively or postoperatively. Conclusion: We found kinematic and functional differences that favor PS TKA. Our results suggest posterior cruciate ligament insufficiency in CR TKA, indicating that perhaps the cam/post systems in PS TKA better maintain knee kinematics and function long term

Euthanasia-related strain and coping strategies in animal shelter employees

Objective—To identify and evaluate coping strategies advocated by experienced animal shelter workers who directly engaged in euthanizing animals. Design—Cross-sectional study. Sample Population—Animal shelters across the United States in which euthanasia was conducted (5 to 100 employees/shelter). Procedures—With the assistance of experts associated with the Humane Society of the United States, the authors identified 88 animal shelters throughout the United States in which animal euthanasia was actively conducted and for which contact information regarding the shelter director was available. Staff at 62 animal shelters agreed to participate in the survey. Survey packets were mailed to the 62 shelter directors, who then distributed them to employees. The survey included questions regarding respondent age, level of education, and role and asked those directly involved in the euthanasia of animals to provide advice on strategies for new euthanasia technicians to deal with the related stress. Employees completed the survey and returned it by mail. Content analysis techniques were used to summarize survey responses. Results—Coping strategies suggested by 242 euthanasia technicians were summarized into 26 distinct coping recommendations in 8 categories: competence or skills strategies, euthanasia behavioral strategies, cognitive or self-talk strategies, emotional regulation strategies, separation strategies, get-help strategies, seek long-term solution strategies, and withdrawal strategies. Conclusions and Clinical Relevance—Euthanizing animals is a major stressor for many animal shelter workers. Information regarding the coping strategies identified in this study may be useful for training new euthanasia technicians

A 50,000-year record of lake-level variations and overflow from Owens Lake, eastern California, USA

A continuous lake-level curve was constructed for Owens Lake, eastern California by integrating lake-core data and shoreline geomorphology with new wind-wave and sediment entrainment modeling of lake-core sedimentology. This effort enabled refinement of the overflow history and development of a better understanding of the effects of regional and global climate variability on lake levels of the paleo-Owens River system during the last 50,000 years. The elevations of stratigraphic sites, plus lake bottom and spillway positions were corrected for vertical tectonic deformation using a differential fault-block model to estimate the absolute hydrologic change of the watershed-lake system. New results include 14C dating of mollusk shells in shoreline deposits, plus post-IR-IRSL dating of a suite of five beach ridges and OSL dating of spillway alluvial and deltaic deposits in deep boreholes. Geotechnical data show the overflow area is an entrenched channel that had erodible sills composed of unconsolidated fluvial-deltaic and alluvial sediment at elevations of ∼1113–1165 m above mean sea level. Owens Lake spilled most of the time at or near minimum sill levels, controlled by a bedrock sill at ∼1113 m. Nine major transgressions at ∼40.0, 38.7, 23.3, 19.3, 15.6, 13.8, 12.8, 11.6, and 10.6 ka reached levels ∼10–45 m above the bedrock sill. Several major regressions at or below the bedrock sill from 36.9 to 28.5 ka, and at ∼17.8, 12.9, and 10.4–8.8 ka indicate little to no overflow during these times. The latest period of overflow occurred ∼10–20 m above the bedrock sill from ∼8.4 to 6.4 ka that was followed by closed basin conditions after ∼6.4 ka. Previous lake core age-depth models were revised by accounting for sediment compaction and using no reservoir correction for open basin conditions, thereby reducing discrepancies between Owens Lake shoreline and lake-core proxy records. The integrated analysis provides a continuous 50 ka lake-level record of hydroclimate variability along the south-central Sierra Nevada that is consistent with other shoreline and speleothem records in the southwestern U.S

Decentralized oceans: Sail-solar shipping for sustainable development in SIDS

Conventional shipping is increasingly unable to address the social and economic needs of remote and underprivileged coastal and island communities. Barriers include rising fuel costs affecting the viability of on-water activities, which are compounded by the challenges presented by a lack of deepwater ports and related infrastructure that prevent docking by larger more fuel-efficient vessels. The environmental externalities of shipping-related fossil-fuel consumption, which harbour both local pollution and anthropogenic climate change impacts, adversely affect these communities. Amid limited research on strategies to address the challenges presented by conventional shipping methods to small island developing States (SIDS), this paper proposes the adoption of policy initiatives for the adoption of small, modern non-fuel vessels that could assist these important yet underserved niches. One of several initiatives developing renewable-energy based shipping solutions is the Greenheart Project, an international non-profit organization in the process of developing an open-source hybrid solar-sail cargo vessel conforming to the conditions faced in coastal and island communities. This paper discusses the socio-economic and environmental challenges presented by conventional shipping with reference to SIDS and the potential of non-fuel shipping. Policy proposals to facilitate the beneficial adoption of such vessels in developing communities will also be offered

Femoral head material loss at the head-neck junction in total hip arthroplasty: the effect of head size, stem material and stem offset

© The Author(s) 2018. Introduction: Material loss at the head-neck junction in total hip arthroplasty may cause adverse clinical symptoms and implant failure. The purpose of this study was to quantitatively examine the effects of head size, stem material and stem offset on material loss of the head-neck taper interface of a single trunnion design in retrieval implants of metal on polyethylene bearing surfaces. Methods: A retrieval study was performed to identify all 28-mm and 32-mm femoral heads from a single implant/taper design implanted for \u3e2 years. This included n = 56 of the 28-mm heads and n = 23 of the 32-mm heads. The 28-mm femoral heads were matched to 32-mm femoral heads based on time in vivo and head length. A coordinate measuring machine was used to determine maximum linear corrosion depth (MLD). Differences in MLD for head diameter, stem material, and stem offset were determined. Results: There were no differences between groups for age, gender, BMI, or implantation time. There was no difference in MLD between 28 mm and 32 mm matched paired head diameters (p = 0.59). There was also no difference in MLD between titanium or cobalt-chromium stems (p = 0.79), and regular or high-offset stems (p = 0.95). Conclusion: There is no statistical difference in femoral head MLD at the head-neck junction in THA between 28-mm and 32-mm matched paired femoral heads, similar or mixed alloy coupled femoral head stem constructs, and regular or high offset stems

The Effect of Subluxation of Articulating Antibiotic Spacers on Bone Defects and Degree of Constraint in Revision Knee Arthroplasty

© 2016 Elsevier Inc. This study investigated whether subluxation of articulating antibiotic spacers is associated with the bone defects found and constraint required when re-implanting the knee arthroplasty components. Staged revisions for infections of primary total knee arthroplasties between 2004 and 2012 were examined. Radiographic sagittal and coronal subluxations of 72 knees were measured prior to second stage revision. Coronal subluxation was found to be associated with increased requirement for constrained knee systems (P\u3c. 0.035). Sagittal subluxation was associated with greater tibia bone defects (P\u3c. 0.037). Careful surgical technique and monitoring of articulating spacers should be done to avoid subluxation after stage 1 revision. If subluxation of the articulating spacer is present, constrained revision knee systems as well as augments should be available at time of re-implantation