bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Topical Tranexamic Acid in Reducing Bleeding and Transfusions in TKA
Authors: Yue Chen , Pei Fuxing , Yang Peiqing , Xie Jinwei , Kang Pengde
Published: May 2015

Educational Objectives

As a result of reading this article, physicians should be able to:

1.

Recognize the efficacy and safety of topical tranexamic acid (TXA) for reducing bleeding and transfusions in total knee arthroplasty (TKA).

2.

Describe the main methods of application of topical TXA in TKA.

3.

Identify the potential advantages of topical TXA compared with intravenous TXA.

4.

Recognize the possible differences between high-concentration and low-concentration topical TXA in reducing bleeding and transfusions in TKA.

Intravenous tranexamic acid (TXA) has been identified to be effective in total knee arthroplasty (TKA), but the effect of topical application is still unclear. Therefore, the authors conducted a meta-analysis to assess the effect of topical TXA in TKA. Twelve trials with a total of 1179 knees were included. The results revealed that the application of topical TXA in TKA significantly reduced total blood loss by a mean of 280.65 mL and reduced transfusions without increasing the risks of deep venous thrombosis and pulmonary embolism. Topical TXA also reduced postoperative drain output by a mean of 194.59 mL and lowered postoperative hemoglobin drop by a mean of 0.66 g/dL. In addition, subgroup analysis showed that high-concentration TXA may be better at reducing bleeding and transfusions than low-concentration TXA. Therefore, the authors concluded that topical TXA can effectively reduce bleeding and transfusion rate in TKA without increasing the risk of deep venous thrombosis and pulmonary embolism, and high-concentration (20 mg/mL or more) topical TXA is recommended. [
Orthopedics.
2015; 38(5):315–324.]
Arthroscopic Transosseous Rotator Cuff Repair: Technical Note, Outcomes, and Complications
Authors: Black Eric M. , Lin Albert , Srikumaran Uma , Jain Nitin , Freehill Michael T.
Published: May 2015

The goal of this study was to review the authors’ initial experience with arthroscopic transosseous rotator cuff repair. Thirty-one patients with full-thickness rotator cuff tears underwent arthroscopic transosseous rotator cuff repair over a 15-month period. Preoperatively, demographics and subjective scores were recorded. Postoperatively, pain levels, subjective shoulder values, satisfaction scores, American Shoulder and Elbow Surgeons (ASES) scores, complications, and reoperations were noted with a minimum 2-year follow-up. The relationships between pre- and intraoperative variables and outcome scores were determined with univariate analysis. Average patient age was 56 years, and 23 patients (74%) were men. Twenty patients (65%) underwent primary rotator cuff repair, and 11 patients (35%) underwent revision repair. Average time to follow-up was 26 months. Average preoperative pain level and subjective shoulder value were 5.1 of 10 and 35%, respectively. Average postoperative scores included pain level of 0.9 of 10, subjective shoulder value of 84%, satisfaction score of 90.6 of 100, and ASES score of 86.3 of 100. There were 3 (9.7%) major and 2 (6%) minor complications. Patients undergoing revision rotator cuff repair had significantly worse outcomes (pain level, subjective shoulder value, ASES score;
P
<.05) compared with those undergoing primary repair, and cortical augmentation did not significantly affect outcome. Overall, outcomes after arthroscopic transosseous rotator cuff repair are good, although patients undergoing revision repair do not have the same outcomes as those undergoing primary cuff repair. The procedure is not without complications (9.7% major, 6% minor complications). Cortical augmentation may be used to supplement fixation, although it does not necessarily affect outcomes. Patients without such augmentation may be at increased risk for suture cutout through the bone. [
Orthopedics.
2015; 38(5):e352–e358.]
Secondary Osteosarcoma: Is There a Predilection for the Chondroblastic Subtype?
Authors: Barker Jordan P. , Monument Michael J. , Jones Kevin B. , Putnam Angelica R. , Randall R. Lor
Published: May 2015

Osteosarcoma is the most common form of primary bone cancer in the adolescent and young adult patient population. Outcomes in patients with secondary osteosarcoma are inferior compared with outcomes in patients with primary osteosarcoma. The goal of this study was to investigate whether there is a predilection for the chondroblastic histologic subtype in secondary osteosarcoma. A retrospective chart review was performed to identify cases of secondary osteosarcoma treated at 1 institution from 1991 to 2012. Histologic subtypes were evaluated by a pathologist, and a review of the literature was also performed to identify the histologic subclassification of additional series of secondary osteosarcomas. Of a total of 131 cases of osteosarcoma, 9 (6.9%) were identified as a secondary malignancy. Only 2 cases (22%) were identified as chondroblastic variants, although 6 (67%) showed some degree of chondroid differentiation. Of the 3 cases meeting the criteria for postradiation osteosarcoma, 2 (67%) were identified as chondroblastic variants and all 3 showed some degree of chondroid differentiation. Five other studies evaluating histologic subtypes in postradiation osteosarcoma showed a cumulative frequency of 20% for the chondroblastic variant. Although the study results did not support the hypothesis of an association between secondary osteosarcoma and the chondroblastic subtype, the high proportion of cases of postradiation osteosarcoma with the chondroblastic subtype and the even higher proportion showing some degree of chondroid differentiation are noteworthy features of this disease. [
Orthopedics.
2015; 38(5):e359–e366.]
A Sclerotic Rim Provides Mechanical Support for the Femoral Head in Osteonecrosis
Authors: Yu Tong , Xie Limin , Chu Fulei
Published: May 2015

Osteonecrotic collapse of the femoral head is a common refractory disease in orthopedics, and the occurrence of collapse is an important factor in the prognosis of this condition. Osteonecrotic collapse of the femoral head can be delayed or prevented by the formation of a sclerotic rim. This study used finite element analysis to evaluate the mechanical role of a proximal sclerotic rim on stress on the femoral head. The study used a healthy man who underwent computed tomography of both hips to generate 3-dimensional finite element models with different proportions of proximal rim sclerosis (0%, 30%, 50%, and 100%). Using a negative directional mechanical load of 400 N along the Z-axis, total deformation, deformation in the negative Z-axial direction (ie, direction of longitudinal compression), maximum principal stress, minimum principal stress, and contact pressure on necrotic tissue were evaluated. For 0%, 30%, 50%, and 100% rim sclerosis, total femoral head deformation was 0.21, 0.205, 0.20, and 0.19 mm, respectively, and maximum principal stress in compression was 9.83, 9.67, 9.16, and 9.05 MPa, respectively. Increases in proximal rim sclerosis decreased all of the measured outcomes. These results suggest that proximal rim sclerosis provides effective mechanical support for the femoral head, offers mechanical protection for necrotic tissue, decreases deformation of the femoral head, and delays or prevents collapse in osteonecrosis. [
Orthopedics.
2015; 38(5):e374–e379.]
Does Intraoperative Fluoroscopy Optimize Limb Length and the Precision of Acetabular Positioning in Primary THA?
Authors: Leucht Philipp , Huddleston Heather G. , Bellino Michael J. , Huddleston James I.
Published: May 2015

Reduced limb length discrepancy and more accurate cup positioning are purported benefits of using fluoroscopy for total hip arthroplasty (THA). The authors compared limb length discrepancy and cup position in 200 patients (group I, posterior approach without fluoroscopy; group II, anterior supine approach with fluoroscopy) who underwent primary THA. Mean limb length discrepancy was 2.7 mm (SD, 5.2 mm; range, −9.8 to 20.9 mm) and 0.7 mm (SD, 3.7 mm; range, −11.8 to 10.5 mm) for groups I and II, respectively (
P
=.002). In group I, 7% of hips had limb length discrepancy greater than 1 cm compared with 3% in group II. Mean cup inclination measured 40.8° (SD, 5.0°; range, 26.1°–53.7°) in group I and 43.4° (SD, 5.6°; range, 31.3°–55.9°) in group II (
P
=.008). In group I, 96% of cups had inclination within 10° of the mean compared with 92% in group II (
P
=.24). Mean anteversion measured 35.3° (SD, 7.1°; range, 17.8°–60.7°) in group I and 25.9° (SD, 8.2°; range, 1.5°–44.8°) in group II (
P
=.0001). In group I, 87% of hips exhibited anteversion within 10° of the mean compared with 76% in group II (
P
=.045). Although the anterior approach with intraoperative fluoroscopy reduced mean limb length discrepancy, the clinical significance of this reduction is unclear. Fluoroscopy reduced the incidence of limb length discrepancy greater than 1 cm. However, the use of fluoroscopy did not help to improve the precision of cup positioning. [
Orthopedics.
2015; 38(5):e380–e386.]
Total Hip Arthroplasty After Lower Extremity Amputation
Authors: Amanatullah Derek F. , Trousdale Robert T. , Sierra Rafael J.
Published: May 2015

There are approximately 1.6 million lower extremity amputees in the United States. Lower extremity amputees are subject to increased physical demands proportional to their level of amputation. Lower extremity amputees have a 6-fold higher risk of developing radiographic osteoarthritis in the ipsilateral hip and a 2-fold risk of developing radiographic osteoarthritis in contralateral hip when compared with the non-amputee population. Additionally, there is a 3-fold increased risk of developing radiographic osteoarthritis in the ipsilateral hip after an above knee amputation when compared with a below knee amputation. The authors retrospectively reviewed 35 total hip arthroplasties after lower extremity amputation. The mean clinical follow-up was 5.3±4.0 years. The mean time from lower extremity amputation to total hip arthroplasty was 12.2±12.8 years after a contralateral amputation and 5.4±6.0 years after an ipsilateral amputation (
P
=.050). The mean time to total hip arthroplasty was 15.6±15.4 years after an above knee amputation and 6.4±6.1 years after a below knee amputation (
P
=.021). There was a statistically significant improvement in the mean Harris Hip Score from 35.9±21.8 to 76.8±12.8 with total hip arthroplasty after a contralateral amputation (
P
<.001). There also was a statistically significant improvement in the mean Harris Hip Score from 25.4±21.7 to 78.6±17.1 with total hip arthroplasty after an ispilateral amputation (
P
<.001). Three (17.7%) total hip arthroplasties after a contralateral amputation and 2 (11.1%) total hip arthroplasties after an ipsilateral amputation required revision total hip arthroplasty. Patients with an ipsilateral amputation or a below knee amputation progress to total hip arthroplasty faster than those with a contralateral amputation or an above knee amputation, respectively. Lower extremity amputees experience clinically significant improvements with total hip arthroplasty after lower extremity amputation. [
Orthopedics.
2015; 38(5):e394–e400.]
Effect of an Emergency Department–Based Electronic System for Musculoskeletal Consultation on Facilitating Care for Common Injuries
Authors: Mears Simon C. , Pantle Hardin A. , Bessman Edward S. , Lifchez Scott D.
Published: May 2015

Access to musculoskeletal consultation in the emergency department (ED) is a nationwide problem. In addition, consultation from a subspecialist may be delayed or may not be available, which can slow down the ED flow and reduce patient satisfaction. The purpose of this study was to review the 1-year results of a change in the authors’ institutional practice to reduce subspecialty consultation for select musculoskeletal problems while still ensuring adequate patient follow-up in orthopedic or plastic surgery clinics for patients not seen by these services in the ED. The authors hypothesized that select injuries could be safely managed in the ED by using an electronic system to ensure appropriate follow-up care. Using Kaizen methodology, a multidisciplinary group (including ED staff, orthopedics, plastic surgery, pediatrics, nursing, radiology, therapy, and administration) met to improve care for select musculoskeletal injuries. A system was agreed on in which ED providers managed select musculoskeletal injuries without subspecialist consultation. Follow-up was organized using an electronic system, which facilitated communication between the ED staff and the secretarial staff of the subspecialist departments. Over a 1-year period, 150 patients were treated using this system. Charts and radiographs were reviewed for missed injuries. Radiographic review revealed 2 missed injuries. One patient had additional back pain and a lumbar spine fracture was found during the subspecialist follow-up visit; it was treated nonoperatively. Another patient appeared to have scapholunate widening on the injury radiograph that was not appreciated in the ED. Of the 150 patients, 51 were seen in follow-up by a subspecialist at the authors’ institution. An electronic system to organize follow-up with a subspecialist allowed the ED providers to deliver safe and effective care for simple musculoskeletal injuries. [
Orthopedics.
2015; 38(5):e407–e410.]
Effect of Simulated Early Weight Bearing on Micromotion and Pullout Strength of Uncemented Distal Femoral Stems
Authors: Barr Jennifer S. , White Jedediah K. , Punt Stephanie E. W. , Conrad Ernest U. , Ching Randal P.
Published: May 2015

The effect of simulated early weight bearing on both micromotion and pullout strength of uncemented distal femoral stems was evaluated in this study. The effect of stem endosteal contact and bone quality on implant pullout strength was also analyzed. A randomized matched-pair study was performed using 8 bilateral pairs of fresh human cadaveric femoral specimens. Each specimen pair was dual-energy x-ray absorptiometry scanned, uniformly implanted, fluoroscopically imaged, and randomly assigned to the cycled or uncycled group. The cycled group received 5000 cycles of axial compressive loading (to 700 N) and the contralateral side was not cycled. Micromotion was monitored during cycling and compared with a failure threshold (150 µm), and all implants underwent direct axial distraction (pullout) testing. During cycling, minimal micromotion was observed with an asymptotic decrease in differential motion between the first and last 50 cycles. Both cycled and uncycled groups demonstrated no statistical difference in average pullout force (4888±2124 N vs 4367±1154 N;
P
=.43). The percentage of cortical contact for each implant was determined from panoramic fluoroscopy images using digital image analysis software. Contact area for the distal third of the stem showed the highest correlation with pullout force and with predicting pullout force. Bone quality did not correlate with pullout force (

r
2

=0.367) or stem contact area (

r
2

=0.394). In sum, press-fit uncemented femoral stems did not loosen or demonstrate decreased pullout strength with early weight bearing simulated by cyclical axial compressive loading. [
Orthopedics.
2015; 38(5):e417–e422.]
The Faculty Voice: Teaching in Accelerated Second Baccalaureate Degree Nursing Programs
Authors: Brandt Cheryl L. , Boellaard Melissa R. , Zorn CeCelia R.
Published: May 2015

Background:

Although accelerated second baccalaureate degree in nursing (ASBSN) programs are growing, little is known about how faculty help ASBSN students to learn.

Method:

In this descriptive qualitative study, faculty in 25 ASBSN programs in 11 midwestern states were asked to describe factors about their teaching. These focused on a comparison with traditional education and an in-depth examination of teaching strategies.

Results:

Faculty (
N
= 129) responded to six open-ended questions on the online survey; a thematic analysis resulted in 24 themes. Themes included Appreciate the Adult Learner With Previous Experiences; Connect Students With Structured Professional Activities; Role Model Professional Learning; and I Like It, I Love It, I Enjoy the Challenge of It.

Conclusion:

Because findings are from the faculty perspective, they enhance understanding of this teaching experience. Implications for faculty development and further research are included. [
J Nurs Educ.
2015;54(5):241–247.]
Short Message Service Use in Clinical Care Through a Simulation Activity
Authors: Schnall Rebecca
Published: May 2015

Background:

Research has shown that the integration of informatics competencies into nursing education especially for Doctor of Nursing Practice (DNP) students, has been inadequate. This article reports on a Short Message Service (SMS) simulation activity for incorporating informatics knowledge and skills into the DNP curriculum.

Method:

DNP students participated in a 3-week simulated ecological momentary assessment using SMS technology. Students rated their experience through a survey and wrote a 1 page narrative describing their experience. Data were analyzed using descriptive statistics and open-ended coding.

Results:

This simulation activity provided information for the future delivery of care using SMS. The cost-saving potential of follow-up messaging reimbursement for providers who use SMS may be a worthwhile investment of health care payers.

Conclusions:

This activity demonstrated the usefulness of SMS technology for helping patients manage their chronic health conditions. Use of SMS would be a reinforcing factor for providers in clinical care if it becomes reimbursable. [
J Nurs Educ.
2015;54(5):290–294.]
Vertebrobasilar Dolichoectasia Induced Hydrocephalus: The Water-Hammer Effect
Authors: Zisimopoulou Vaso , Ntouniadaki Aikaterini , Aggelidakis Panagiotis , Siatouni Anna , Gatzonis Stylianos , Tavernarakis Antonios
Published: May 2015

Vertebrobasilar dolichoectasia is a clinical entity associated rarely with obstructive hydrocephalus. We present a 48-year old male with a profound dilatation of the ventricular system due to a dolichoectatic basilar artery, as appeared in imaging studies. The patient suffered from longstanding hydrocephalus and presenile dementia. The underlying mechanism for obstructive hydrocephalus due to vertebrobasilar dolichoectasia is considered to be both a water-hammer effect and a direct compression of adjacent structures. We suggest prompt surgical intervention upon diagnosis as a first choice treatment in order to avoid further complications.
Geology of the Manning Park area, British Columbia
Authors: Coates J A
Published: May 2015

The Manning Park map-area, located about 150 miles east of Vancouver and covering about 200 square miles, is outlined in general by the borders of the park. Rocks within this region range in age from Permian (?) or Middle Triassic to Eocene, although rocks
studied in detail are of Sinemurian to Albian age. These Sinemurian to Albian rocks are exposed in a fault bounded trough or graben-like structure thought to be the southward continuation of the Tyaughton Trough. The oldest rocks in the Manning Park area are limestone, chert, argillite and altered
basic volcanics of the Hozameen Group of Permian (?) and/or Middle Triassic age. Volcanics, greywacke, arg·illite and minor limestone of the Ladner Group are of Sinemurian to Bajocian age, and represent the oldest rocks confined to the Tyaughton Trough in this region. The Ladner Group is
overlain disconformably by sandstone, siltstone, shale and minor conglomerate of the Upper Jurassic Dewdney Creek Group, which is in turn overlain disconformably by Hauterivian to Albian shale, siltstone, greywacke and conglomerate of the Jackass Mountain Group. Sediments from all these groups are
marine in origin. Albian nonmarine shale, sandstone and conglomerate of the Pasayten Group marks the end of sedimentation in the map- area.
Granitic rocks are of minor importance within this part of the Tyaughton Trough. The eastern margin of the Jura-Cretaceous sediments is in fault contact with the Eagle granodiorite-tonalite-migmatite complex. Small tonalite stocks of Upper Cretaceous age (84 m. y.) intrude the Jura-Cretaceous
sediments in the northwest corner of the map-area. Tonalite and grandiorite of Eocene age ( 46 m. y. ) , the Castle Peak stock, intrudes Albian sediments astride the International Boundary. Sedimentation in the Manning Park area was directed from the east throughout the Jurassic and the early part
of the Lower Cretaceous. Sediments derived from the west first entered the area in the Albian. The area underwent a single, major period of deformation in the earliest Late Cretaceous, when the rocks were folded and thrusted in an easterly direction.
Sedimentology, sequence stratigraphy, organic petrology, geochemistry, and palynology of Mannville Group coals in south-central Alberta
Authors: Banerjee I , Kalkreuth W
Published: May 2015

An integrated case study of the stratigraphy, sedimentology, geochemistry, organic petrology and palynology of subsurface coal and coal-bearing strata of the Lower Cretaceous Mannville Group has resulted in the construction of a sequence stratigraphic model of
paralic coal. In Alberta, the unconformity-bounded Mannville Group is a 100 to 300 m thick, siliciclastic unit comprising a second-order depositional sequence that can be divided into six third-order sequences. The databases for this study consisted of geophysical logs, examination of cored
intervals, and organic petrological and geochemical analyses of samples of coal and associated rocks.
Examination of the stratigraphy, sedimentology, and palynological, petrographic, and geochemical profiles of three specific coal seams also revealed high-frequency fourth-order sequences and, in a 12 m thick coal seam, at least three transgressive-regressive cycles and two
unconformities.
Implications of Canada's 4th generation seismic hazard model for Canadian dams
Authors: Adams J , Halchuk S
Published: May 2015

We summarize the methods being used for the new seismic hazard maps of Canada and estimate median ground motion on firm soil sites for a probability of exceedence of 2% in 50 years (1/2475 per annum). Spectral acceleration at 0.2, 0.5, 1.0 and 2.0 second
periods and peak acceleration will form the basis of the seismic provisions of the 2005 National Building Code of Canada. The future design of common buildings to 1/2475 p.a. may raise public concerns about dams designed to "only" 1/1000 p.a. shaking, unless their expected performance is shown to be
substantially better. NBCC2005 hazard values may be useful for screening dam projects. However, as seismic hazard may be very sensitive to the choice of input parameters site-specific evaluation remains essential for 1/10,000 p.a. designs.
Differentiation of Cardiomyocytes from Human Pluripotent Stem Cells Using Monolayer Culture
Authors: Batalov Ivan , Feinberg Adam W.
Published: May 2015

Human pluripotent stem cells (PSCs) are a promising cell source for cardiac tissue engineering and cell-based therapies for heart repair because they can be expanded in vitro and differentiated into most cardiovascular cell types, including cardiomyocytes. During embryonic heart development, this differentiation occurs under the influence of internal and external stimuli that guide cells to go down the cardiac lineage. In order to differentiate PSCs in vitro, these or similar stimuli need to be provided in a controlled manner. However, because it is not possible to completely recapitulate the embryonic environment, the factors essential for cardiac differentiation of PSCs in vitro need to be experimentally determined and validated. Since PSCs were first developed, significant progress has been made in optimizing techniques for their differentiation toward cardiomyocytes. In this review, we will summarize recent advances in these techniques, with particular focus on monolayer-based methods that have improved the efficiency and scalability of cardiomyocyte differentiation.
Tackling Imported Malaria: An Elimination Endgame
Authors: Sturrock Hugh J. W. , Roberts Kathryn W. , Wegbreit Jennifer , Ohrt Colin , Gosling Roly D.
Published: May 2015

As countries move toward malaria elimination, imported infections become increasingly significant as they often represent the majority of cases, can sustain transmission, cause resurgences, and lead to mortality. Here we review and critique current methods to prevent malaria importation in countries pursuing elimination and explore methods applied in other transmission settings and to other diseases that could be transferred to support malaria elimination. To improve intervention targeting we need a better understanding of the characteristics of populations importing infections and their patterns of migration, improved methods to reliably classify infections as imported or acquired locally, and ensure early and accurate diagnosis. The potential for onward transmission in the most receptive and vulnerable locations can be predicted through high-resolution risk mapping that can help malaria elimination or prevention of reintroduction programs target resources. Cross border and regional initiatives can be highly effective when based on an understanding of human and parasite movement. Ultimately, determining the optimal combinations of approaches to address malaria importation will require an evaluation of their impact, cost effectiveness, and operational feasibility.
Dengue Seroprevalence of Healthy Adults in Singapore: Serosurvey Among Blood Donors, 2009
Authors: Low Swee-Ling , Lam Sally , Wong Wing-Yan , Teo Diana , Ng Lee-Ching , Tan Li-Kiang
Published: May 2015

Routine national notifications of dengue cases typically do not reflect the true dengue situation due to large proportion of unreported cases. Serosurveys, when conducted periodically, could shed light on the true dengue infections in the population. To determine the magnitude of dengue infections of the adult population in Singapore following the outbreak in 2007, we performed a cross-sectional study on blood donor samples from December 2009 to February 2010. The residual blood of 3,995 donors (aged 16–60 years) was screened for the presence of dengue-specific immunoglobulin G (IgG) and IgM using enzyme-linked immunosorbent assay (ELISA) kits. The age-weighted IgG prevalence of residents was 50.8% (N = 3,627, 95% confidence interval [CI] = 49.4–52.3%). Dengue IgG prevalence increased with age, with the lowest in 16–20 years age group (16.1%) and the highest in 56–60 years age group (86.6%). Plaque reduction neutralization test (PRNT) on samples of young resident adults (aged 16–30 years) revealed lower prevalence of neutralizing antibodies to each serotype, ranging from 5.4% to 20.3% compared with the older age groups. The level of exposure to dengue among the young adults is relatively low despite the endemicity of the disease in Singapore. It partially explains the population's susceptibility to explosive outbreaks and the high incidence rate among young adults.
Wind extraction potential from ensemble Kalman filter assimilation of stratospheric ozone using a global shallow water model
Authors: Allen D. R. , Hoppel K. W. , Kuhl D. D.
Published: May 2015

Abstract. The feasibility of extracting wind information from stratospheric ozone observations is tested using ensemble Kalman filter (EnKF) data assimilation (DA) and a global shallow water model that includes advection of an ozone-like tracer. Simulated observations are created from a truth run (TR) that resembles the Northern Hemisphere winter stratosphere with a polar vortex disturbed by planetary-scale wave forcing. Ozone observations mimic sampling of a polar-orbiting satellite, while geopotential height observations are randomly placed in space and time. EnKF experiments are performed assimilating ozone, height, or both, over a 10-day period. The DA is also implemented using two different pairs of flow variables: zonal and meridional wind (EnKF-uv) and stream function and velocity potential (EnKF-ψχ). Each experiment is tuned for optimal localization length, while the ensemble spread is adaptively inflated using the TR. The experiments are evaluated using the maximum wind extraction potential (WEP). Ozone only assimilation improves winds (WEP = 46% for EnKF-uv, and 58% for EnKF-ψχ), but suffers from spurious gravity wave generation. Application of nonlinear normal mode initialization (NMI) greatly reduces the unwanted imbalance and increases the WEP for EnKF-uv (84%) and EnKF-ψχ (81%). Assimilation of only height observations also improved the winds (WEP = 60% for EnKF-uv, and 69% for EnKF-ψχ), with much less imbalance compared to the ozone experiment. The assimilation of both height and ozone performed the best, with WEP increasing to ~87% (~90% with NMI) for both EnKF-uv and EnKF-ψχ, demonstrating that wind extraction from ozone assimilation can be beneficial even in a data-rich environment. Ozone assimilation particularly improves the tropical winds, which are not well constrained by height observations due to lack of geostrophy.
Large eddy simulation of ship tracks in the collapsed marine boundary layer: a case study from the Monterey area ship track experiment
Authors: Berner A. H. , Bretherton C. S. , Wood R.
Published: May 2015

Abstract. For the first time, a large eddy simulation (LES) coupled to a bulk aerosol scheme is used to simulate an aircraft-sampled ship track. The track was formed by the M/V Sanko Peace on 13 June 1994 in a shallow drizzling boundary layer with high winds but very low background aerosol concentrations (10 cm−3). A Lagrangian framework is used to simulate the evolution of a short segment of track as it is advected away from the ship for 8 h (a downwind distance exceeding 570 km). Using aircraft observations for initialization, good agreement is obtained between the simulated and observed features of the ambient boundary layer outside the track, including the organization of the cloud into mesoscale rolls. After 8 h, a line of aerosol is injected to start the ship track. The simulation successfully reproduces the significant albedo enhancement and suppression of drizzle observed within the track. The aerosol concentration within the track dilutes as it broadens due to turbulent mixing. A sensitivity study shows the broadening rate strongly depends on the alignment between the track and the wind-aligned boundary layer rolls, as satellite images of ship tracks suggest. Entrainment is enhanced within the simulated track, but the observed 100 m elevation of the ship track above the surrounding layer is not simulated, possibly because the LES quickly sharpens the rather weak observed inversion. Liquid water path within the simulated track increases with time even as the ambient liquid water path is decreasing. The albedo increase in the track from liquid water and cloud fraction enhancement (second indirect effect) eventually exceeds that from cloud droplet number increases (first indirect or Twomey effect). In a sensitivity study with a higher initial ambient aerosol concentration, stronger ship track aerosol source, and much weaker drizzle, there is less liquid water inside the track than outside for several hours downwind, consistent with satellite estimates for such situations. In that case, the Twomey effect dominates throughout, although, as seen in satellite images, the albedo enhancement of the track is much smaller.
Drivers of the tropospheric ozone budget throughout the 21st century under the medium-high climate scenario RCP 6.0
Authors: Revell L. E. , Tummon F. , Stenke A. , Sukhodolov T. , Coulon A. , Rozanov E. , Garny H. , Grewe V. , Peter T.
Published: May 2015

Abstract. Because tropospheric ozone is both a greenhouse gas and harmful air pollutant, it is important to understand how anthropogenic activities may influence its abundance and distribution through the 21st century. Here, we present model simulations performed with the chemistry–climate model SOCOL, in which spatially disaggregated chemistry and transport tracers have been implemented in order to better understand the distribution and projected changes in tropospheric ozone. We examine the influences of ozone precursor emissions (nitrogen oxides (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs)), climate change (including methane effects) and stratospheric ozone recovery on the tropospheric ozone budget, in a simulation following the climate scenario Representative Concentration Pathway (RCP) 6.0 (a medium-high, and reasonably realistic climate scenario). Changes in ozone precursor emissions have the largest effect, leading to a global-mean increase in tropospheric ozone which maximizes in the early 21st century at 23% compared to 1960. The increase is most pronounced at northern midlatitudes, due to regional emission patterns: between 1990 and 2060, northern midlatitude tropospheric ozone remains at constantly large abundances: 31% larger than in 1960. Over this 70-year period, attempts to reduce emissions in Europe and North America do not have an effect on zonally averaged northern midlatitude ozone because of increasing emissions from Asia, together with the long lifetime of ozone in the troposphere. A simulation with fixed anthropogenic ozone precursor emissions of NOx, CO and non-methane VOCs at 1960 conditions shows a 6% increase in global-mean tropospheric ozone by the end of the 21st century, with an 11 % increase at northern midlatitudes. This increase maximizes in the 2080s and is mostly caused by methane, which maximizes in the 2080s following RCP 6.0, and plays an important role in controlling ozone directly, and indirectly through its influence on other VOCs and CO. Enhanced flux of ozone from the stratosphere to the troposphere as well as climate change-induced enhancements in lightning NOx emissions also increase the tropospheric ozone burden, although their impacts are relatively small. Overall, the results show that under this climate scenario, ozone in the future is governed largely by changes in methane and NOx; methane induces an increase in tropospheric ozone that is approximately one-third of that caused by NOx. Climate impacts on ozone through changes in tropospheric temperature, humidity and lightning NOx remain secondary compared with emission strategies relating to anthropogenic emissions of NOx, such as fossil fuel burning. Therefore, emission policies globally have a critical role to play in determining tropospheric ozone evolution through the 21st century.
Global HCFC-22 measurements with MIPAS: retrieval, validation, climatologies and trends
Authors: Chirkov M. , Stiller G. P. , Laeng A. , Kellmann S. , von Clarmann T. , Boone C. , Elkins J. W. , Engel A. , Glatthor N. , Grabowski U. , Harth C. M. , Kiefer M. , Kolonjari F. , Krummel P. B. , Linden A. , Lunder C. R. , Miller B. R. , Montzka S. A. , Mühle J. , O'Doherty S. , Orphal J. , Prinn R. G. , Toon G. , Vollmer M. K. , Walker K. A. , Weiss R. F. , Wiegele A. , Young D.
Published: May 2015

Abstract. We report on HCFC-22 data acquired by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) in reduced spectral resolution nominal mode in the period from January 2005 to April 2012 from version 5.02 level-1b spectral data and covering an altitude range from the upper troposphere (above cloud top altitude) to about 50 km. The profile retrieval was performed by constrained nonlinear least squares fitting of measured limb spectral radiances to modelled spectra. The spectral ν4-band at 816.5 ± 13 cm−1 was used for the retrieval. A Tikhonov-type smoothing constraint was applied to stabilise the retrieval. In the lower stratosphere, we find a global volume mixing ratio of HCFC-22 of about 185 pptv in January 2005. The linear growth rate in the lower latitudes lower stratosphere was about 6 to 7 pptv yr−1 in the period 2005–2012. The obtained profiles were compared with ACE-FTS satellite data v3.5, as well as with MkIV balloon profiles and in situ cryosampler balloon measurements. Between 13 and 22 km, average agreement within −3 to +5 pptv (MIPAS–ACE) with ACE-FTS v3.5 profiles is demonstrated. Agreement with MkIV solar occultation balloon-borne measurements is within 10–20 pptv below 30 km and worse above, while in situ cryosampler balloon measurements are systematically lower over their full altitude range by 15–50 pptv below 24 km and less than 10 pptv above 28 km. Obtained MIPAS HCFC-22 time series below 10 km altitude are shown to agree mostly well to corresponding time series of near-surface abundances from NOAA/ESRL and AGAGE networks, although a more pronounced seasonal cycle is obvious in the satellite data, probably due to tropopause altitude fluctuations and subsidence of polar winter stratospheric air into the troposphere. A parametric model consisting of constant, linear, quasi-biennial oscillation (QBO) and several sine and cosine terms with different periods has been fitted to the temporal variation of stratospheric HCFC-22 for all 10° latitude/1 to 2 km altitude bins. The relative linear variation was always positive, with relative increases of 40–70% decade−1 in the tropics and global lower stratosphere, and up to 120% decade−1 in the upper stratosphere of the northern polar region and the southern extratropical hemisphere. In the middle stratosphere between 20 and 30 km, the observed trend is not consistent with the age of stratospheric air-corrected trend at ground, but stronger positive at the Southern Hemisphere and less strong increasing in the Northern Hemisphere, hinting towards changes in the stratospheric circulation over the observation period.
The importance of Asia as a source of black carbon to the European Arctic during springtime 2013
Authors: Liu D. , Quennehen B. , Darbyshire E. , Allan J. D. , Williams P. I. , Taylor J. W. , Bauguitte S. J.-B. , Flynn M. J. , Gallagher M. W. , Bower K. N. , Choularton T. W. , Coe H.
Published: May 2015

Abstract. Black carbon aerosol (BC) deposited to the Arctic sea ice or present in the free troposphere can significantly affect the Earth's radiation budget at high latitudes yet the BC burden in these regions and the regional source contributions are poorly constrained. Aircraft measurements of aerosol composition in the European Arctic were conducted during the Aerosol–Cloud Coupling And Climate Interactions in the Arctic (ACCACIA) campaign in March 2013. Pollutant plumes were encountered throughout the lower to upper Arctic troposphere featuring enhancements in CO and aerosol mass loadings, which were chemically speciated into BC and non-refractory sulphate and organic matter. FLEXPART-WRF simulations have been performed to evaluate the likely contribution to the pollution from regional ground sources. By combining up-to-date anthropogenic and open fire biomass burning (OBB) inventories, we have been able to compare the contributions made to the observed pollution layers from the sources of eastern/northern Asia (AS), Europe (EU) and North America (NA). Over 90% of the contribution to the pollution was shown to arise from non-OBB anthropogenic sources. AS sources were found to be the major contributor to the BC burden, increasing background BC loadings by a factor of 3–5 to 100.8 ± 48.4 ng s m−3 and 55.8 ± 22.4 ng s m−3 in the middle and upper troposphere respectively. AS plumes close to the tropopause (about 7.5–8 km) were also observed, with BC concentrations ranging from 55 to 73 ng s m−3, which will potentially have a significant radiative impact. EU sources influenced the middle troposphere with a BC mean concentration of 70.8 ± 39.1 ng s m−3 but made a minor contribution to the upper troposphere due to the relatively high latitude of the source region. The contribution of NA was shown to be much lower at all altitudes with BC mean concentration of 20 ng s m−3. The BC transported to the Arctic is mixed with a non-BC volume fraction representing between 90–95% of the mass, and has a relatively uniform core size distribution with mass median diameter 190–210 nm and geometric standard deviation σg = 1.55–1.65 and this varied little across all source regions. It is estimated that 60–95% of BC is scavenged between emission and receptor based on BC/ΔCO comparisons between source inventories and measurement. We show that during the springtime of 2013, the anthropogenic pollution particularly from sources in Asia, contributed significantly to BC across the European Arctic free troposphere. In contrast to previous studies, the contribution from open wildfires was minimal. Given that Asian pollution is likely to continue to rise over the coming years, it is likely that the radiative forcing in the Arctic will also continue to increase.
Evaluation of regional background particulate matter concentration based on vertical distribution characteristics
Authors: Han S. , Zhang Y. , Wu J. , Zhang X. , Tian Y. , Wang Y. , Ding J. , Yan W. , Bi X. , Shi G. , Cai Z. , Yao Q. , Huang H. , Feng Y.
Published: May 2015

Abstract. Heavy regional particulate matter (PM) pollution in China has resulted in an important and urgent need for joint control actions among cities. It's advisable to improve the understanding of regional background concentration of PM for the development of efficient and effective joint control policies. With the increase of vertical height the influence of source emission on local air quality is weakening, but the characteristics of regional pollution gradually become obvious. A method to estimate regional background PM concentration is proposed in this paper, based on the vertical variation periodic characteristics of the atmospheric boundary layer structure and particle mass concentration, as well as the vertical distribution of particle size, chemical composition and pollution source apportionment. According to the method, the averaged regional background PM2.5 concentration, being extracted from the original time series in Tianjin, was 40.0 ± 20.2, 63.6 ± 16.9 and 53.2 ± 11.1 μg m−3, respectively, in July, August and September.
Estimating reflectivity values from wind turbines for analyzing the potential impact on weather radar services
Authors: Angulo I. , Grande O. , Jenn D. , Guerra D. , de la Vega D.
Published: May 2015

Abstract. The World Meteorological Organization (WMO) has repeatedly expressed concern over the increasing number of impact cases of wind turbine farms on weather radars. Current signal processing techniques to mitigate wind turbine clutter (WTC) are scarce, so the most practical approach to this issue is the assessment of the potential interference from a wind farm before it is installed. To do so, and in order to obtain a WTC reflectivity model, it is crucial to estimate the radar cross section (RCS) of the wind turbines to be built, which represents the power percentage of the radar signal that is backscattered to the radar receiver. For the proposed model, a representative scenario has been chosen in which both the weather radar and the wind farm are placed on clear areas; i.e., wind turbines are supposed to be illuminated only by the lowest elevation angles of the radar beam. This paper first characterizes the RCS of wind turbines in the weather radar frequency bands by means of computer simulations based on the physical optics theory and then proposes a simplified model to estimate wind turbine RCS values. This model is of great help in the evaluation of the potential impact of a certain wind farm on the weather radar operation.
Comparison of GC/time-of-flight MS with GC/quadrupole MS for halocarbon trace gas analysis
Authors: Hoker J. , Obersteiner F. , Bönisch H. , Engel A.
Published: May 2015

Abstract. We present the application of time-of-flight mass spectrometry (TOF MS) for the analysis of halocarbons in the atmosphere after cryogenic sample preconcentration and gas chromatographic separation. For the described field of application, the quadrupole mass spectrometer (QP MS) is a state-of-the-art detector. This work aims at comparing two commercially available instruments, a QP MS and a TOF MS, with respect to mass resolution, mass accuracy, stability of the mass axis and instrument sensitivity, detector sensitivity, measurement precision and detector linearity. Both mass spectrometers are operated on the same gas chromatographic system by splitting the column effluent to both detectors. The QP MS had to be operated in optimised single ion monitoring (SIM) mode to achieve a sensitivity which could compete with the TOF MS. The TOF MS provided full mass range information in any acquired mass spectrum without losing sensitivity. Whilst the QP MS showed the performance already achieved in earlier tests, the sensitivity of the TOF MS was on average higher than that of the QP MS in the "operational" SIM mode by a factor of up to 3, reaching detection limits of less than 0.2 pg. Measurement precision determined for the whole analytical system was up to 0.2% depending on substance and sampled volume. The TOF MS instrument used for this study displayed significant non-linearities of up to 10% for two-thirds of all analysed substances.
Lunar periodicity in the shell flux of planktonic foraminifera in the Gulf of Mexico
Authors: Jonkers L. , Reynolds C. E. , Richey J. , Hall I. R.
Published: May 2015

Abstract. Synchronised reproduction offers clear benefits to planktonic foraminifera – an important group of marine calcifiers – as it increases the chances of successful gamete fusion. Such synchrony requires tuning to an internal or external clock. Evidence exists for lunar reproductive cycles in some species, but its recognition in shell flux time series has proven difficult, raising questions about reproductive strategies. Using spectral analysis of a 4-year time series (mostly at weekly resolution) from the northern Gulf of Mexico, we show that the shell flux of Globorotalia menardii, Globigerinella siphonifera, Orbulina universa, Globigerinoides sacculifer, Globigerinoides ruber (both pink and white varieties), Pulleniatina obliquiloculata, Neogloboquadrina dutertrei, Globigerinella calida and Globigerinita glutinata is characterised by lunar periodicity. However, the lunar rhythm is not present in all size fractions of each species and tends to be more dominant in the flux of larger shells, consistent with reproduction being more prevalent in larger specimens. Lunar periodicity is superimposed on longer term/seasonal changes in the shell fluxes, but accounts for a significant part of the variance in the fluxes. The amplitude of the lunar cycle increases roughly proportional with the magnitude of the flux, demonstrating that most of the population is indeed affected by lunar-phased synchronisation. In most species peak fluxes occur predominantly around, or just after, full moon. Only G. siphonifera and G. calida show a contrasting pattern with peaks concentrated around new moon. Although the exact cause of the synchronisation remains elusive, our data considerably increase the number of species for which lunar synchronised reproduction is reported and suggest that such reproductive behaviour is common in many species of planktonic foraminifera.