bluuebunny/crossref_metadata_2025 huggingface dataset:
Femtosecond Laser-assisted Arcuate Keratotomy Versus Toric IOL Implantation for Correcting Astigmatism
Authors: Yoo Aeri , Yun Samyoung , Kim Jae Yong , Kim Myoung Joon , Tchah Hungwon
Published: September 2015

PURPOSE:

To evaluate the clinical efficacy and safety of femtosecond laser-assisted arcuate keratotomy (FS-AK) versus toric intraocular lens (IOL) implantation for correcting astigmatism in patients with cataract.

METHODS:

A retrospective chart review was performed. All patients had senile cataracts with corneal astigmatism (range: +1.00 to +3.00 diopters [D]) before cataract surgery. Twenty-five patients agreed to undergo toric IOL implantation (the toric IOL group). Twenty-three patients did not agree to undergo toric IOL implantation despite astigmatism; however, these patients were not satisfied with their remaining astigmatism following cataract surgery and requested astigmatism correction using FS-AK (the FS-AK group). Visual acuity and intraocular pressure were evaluated, and automated refraction, keratometry, and slit-lamp examinations were performed at 1 day, 1 week, 1 month, and 5 months after surgery.

RESULTS:

Refractive astigmatism decreased in both groups. The mean preoperative and postoperative refractive cylinders were 1.71 ± 1.15 and 0.78 ± 1.06 D, respectively, in the FS-AK group (
P
< .001) and 1.67 ± 0.13 and 0.83 ± 0.097 D, respectively, in the toric IOL group (
P
< .001). There were no statistically significant differences between groups at any time during the follow-up period.

CONCLUSIONS:

FS-AK is a fast, customizable, adjustable, precise, and safe procedure for reducing refractive errors in patients with residual astigmatism after cataract surgery. The results of this procedure are comparable to the toric IOL.

[
J Refract Surg.
2015;31(9):574–578.]
Optical Zone Centration Accuracy Using Corneal Fixation-based SMILE Compared to Eye Tracker-based Femtosecond Laser-assisted LASIK for Myopia
Authors: Reinstein Dan Z. , Gobbe Marine , Gobbe Louis , Archer Timothy J. , Carp Glenn I.
Published: September 2015

PURPOSE:

To compare the optical zone centration accuracy between myopic eyes treated with small incision lenticule extraction (SMILE) and LASIK.

METHODS:

Retrospective analysis of 100 consecutive eyes treated with SMILE (the SMILE group) with the corneal fixation-based centration VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) and a matched group of 100 eyes treated with LASIK (the LASIK group) with VisuMax flap creation and eye tracker-based centration MEL 90 excimer laser (Carl Zeiss Meditec) ablation. In SMILE, the corneal vertex of the coaxially fixating eye was aligned with the vertex of the curved contact glass. In LASIK, the treatment was centered on the coaxially sighted corneal light reflex (first Purkinje image). A tangential (instantaneous) curvature preoperative to postoperative difference map was generated for each eye. A fixed grid and set of concentric circles were superimposed on the difference map to measure the offset between the optical zone center and corneal vertex (0,0), and vector analysis was used for comparative analysis at 3 months postoperatively.

RESULTS:

Mean centration offset was 0.20 ± 0.11 mm for the SMILE group and 0.17 ± 0.10 mm for the LASIK group, with no statistically significant difference between groups (
P
>.05). In the SMILE group, the optical zone was centered within 0.1 mm of the corneal vertex in 17% of eyes, within 0.2 mm in 55% of eyes, within 0.3 mm in 81% of eyes, and within 0.4 mm in 96% of eyes. In the LASIK group, the optical zone was centered within 0.1 mm of the corneal vertex in 24% of eyes, within 0.2 mm in 62% of eyes, within 0.3 mm in 92% of eyes, and within 0.4 mm in 98% of eyes. There was no systematic directional decentration in either group.

CONCLUSION:

Optical zone centration accuracy was no different between SMILE and LASIK with the MEL 90 laser.

[
J Refract Surg.
2015;31(9):586–592.]
Opaque Bubble Layer Risk Factors in Femtosecond Laser-assisted LASIK
Authors: Courtin Romain , Saad Alain , Guilbert Emmanuel , Grise-Dulac Alice , Gatinel Damien
Published: September 2015

PURPOSE:

To determine the characteristics and risk factors for occurrence of opaque bubble layer (OBL) during femtosecond laser-assisted flap creation for LASIK.

METHODS:

One hundred ninety-eight eyes of 102 consecutive patients who underwent LASIK flap creation performed with the Alcon WaveLight FS200 laser (Alcon Laboratories, Inc., Fort Worth, TX) were retrospectively analyzed in a cohort study. Preoperative manifest refraction, corneal keratometry, central corneal thickness, white-to-white corneal diameter, corneal hysteresis, corneal resistance factor, and programmed flaps parameters were collected. Digital images automatically recorded after flap creation were analyzed to measure OBL areas. Correlation tests were performed between preoperative corneal parameters and OBL areas.

RESULTS:

The incidence rate of OBL was 48% (103 eyes). The mean OBL area as a percentage of the corneal flap area in the OBL group was 4.25% ± 7.16% (range: 0% to 32.9%). The central corneal thickness, corneal resistance factor, and corneal hysteresis were significantly positively correlated with the OBL area (
r
= 0.242,
P
= .001;
r
= 0.254,
P
= .028; and
r
= 0.351,
P
< .0001, respectively). Corneal hysteresis and OBL area were positively correlated, independently of the central corneal thickness and other confounder factors with standardized coefficient (
r
= 0.353 ± 0.227,
P
= .002).

CONCLUSIONS:

This study confirms the already known OBL risk factors with a larger cohort and suggests for the first time that an elevated corneal hysteresis is an independent predictive risk for OBL occurrence.

[J Refract Surg.
2015;31(9):608–612.]
In Vivo Confocal Microscopic Imaging of the Cornea After Femtosecond and Excimer Laser-assisted Penetrating Keratoplasty
Authors: Resch Miklós D. , Zemova Elena , Marsovszky László , Szentmáry Nóra , Bauer Florian , Daas Loay , Pattmöller Max , El-Husseiny Moatasem , Németh János , Nagy Zoltán Z. , Seitz Berthold
Published: September 2015

PURPOSE:

To examine the microstructure of the cornea after excimer and femtosecond laser-assisted penetrating keratoplasty (ELAK and FLAK) in eyes with Fuchs’ dystrophy and keratoconus.

METHODS:

Fifty-seven patients were divided into four groups according to corneal disease and surgical technique: Fuchs’ dystrophy and ELAK (n = 9; mean age: 70.4 ± 10.6 years); Fuchs’ dystrophy and FLAK (n = 13; mean age: 64.3 ± 11.2 years); keratoconus and ELAK (n = 9; mean age: 47.4 ± 13.9 years); and keratoconus and FLAK (n = 9; mean age: 43.5 ± 13.8 years). The control group comprised individuals without ocular disease (n = 17; mean age: 39.9 ± 17.3 years). In vivo investigation of the corneal graft and graft–host junction zone was performed with confocal corneal microscopy.

RESULTS:

All corneal grafts were transparent and no rejection reaction could be observed during the follow-up period. Confocal microscopy revealed no difference in basal epithelial cell density compared to controls. Anterior keratocyte density was lower than in the control group (818 ± 131 cells/mm
2
) in all four treatment groups (596 ± 174, 586 ± 113, 529 ± 75, 552 ± 91 cells/mm
2
). Langerhans cells could barely be seen; there was no difference in the cutting edge configuration and wound integrity.

CONCLUSIONS:

In vivo confocal microscopy provided evidence that good alignment of graft–host junction could be created with both techniques. The excimer laser was not inferior to the femtosecond laser in performing corneal cuts. The low density of Langerhans cells revealed well-controlled cellular immunological response and sustained corneal integrity in both laser groups.

[
J Refract Surg.
2015;31(9):620–626.]
Objective Evaluation of Planned Versus Achieved Stromal Thickness Reduction in Myopic Femtosecond Laser-assisted LASIK
Authors: Kanellopoulos Anastasios John , Georgiadou Stella , Asimellis George
Published: September 2015

PURPOSE:

To evaluate corneal stromal thickness reduction and compare to attempted and achieved ablation depth in a consecutive case series study of myopic LASIK.

METHODS:

Stromal thickness reduction was retrospectively evaluated in 205 consecutive eyes of 205 patients undergoing myopic and myopic astigmatic LASIK. Anterior segment optical coherence tomography was performed preoperatively and 3 months postoperatively. Epithelial thickness remodeling was also accounted for to achieve objective stromal thickness reduction. The derived maximum stromal thickness reduction was then compared to the programmed (planned) maximum ablation depth. Deviation of planned versus achieved maximum stromal thickness changes was correlated with residual refractive error.

RESULTS:

The 3-month stromal reduction was 86.01 ± 28.28
µ
m, compared to the average programmed maximum ablation depth of 88.48 ± 26.05
µ
m. The attempted versus achieved thickness outliers correlated with deviations in achieved refractive correction.

CONCLUSIONS:

Actual objective stromal thickness reduction following myopic LASIK correlates well with the attempted versus achieved refractive change.

[
J Refract Surg.
2015;31(9):628–632.]
Refractive Outcomes, Contrast Sensitivity, HOAs, and Patient Satisfaction in Moderate Myopia: Wavefront-Optimized Versus Tissue-Saving PRK
Authors: Nassiri Nader , Sheibani Kourosh , Azimi Abbas , Khosravi Farinaz Mahmoodi , Heravian Javad , Yekta Abasali , Moghaddam Hadi Ostadi , Nassiri Saman , Yasseri Mehdi , Nassiri Nariman
Published: September 2015

PURPOSE:

To compare refractive outcomes, contrast sensitivity, higher-order aberrations (HOAs), and patient satisfaction after photorefractive keratectomy for correction of moderate myopia with two methods: tissue saving versus wavefront optimized.

METHODS:

In this prospective, comparative study, 152 eyes (80 patients) with moderate myopia with and without astigmatism were randomly divided into two groups: the tissue-saving group (Technolas 217z Zyoptix laser; Bausch & Lomb, Rochester, NY) (76 eyes of 39 patients) or the wavefront-optimized group (WaveLight Allegretto Wave Eye-Q laser; Alcon Laboratories, Inc., Fort Worth, TX) (76 eyes of 41 patients). Preoperative and 3-month postoperative refractive outcomes, contrast sensitivity, HOAs, and patient satisfaction were compared between the two groups.

RESULTS:

The mean spherical equivalent was −4.50 ± 1.02 diopters. No statistically significant differences were detected between the groups in terms of uncorrected and corrected distance visual acuity and spherical equivalent preoperatively and 3 months postoperatively. No statistically significant differences were seen in the amount of preoperative to postoperative contrast sensitivity changes between the two groups in photopic and mesopic conditions. HOAs and Q factor increased in both groups postoperatively (
P
= .001), with the tissue-saving method causing more increases in HOAs (
P
= .007) and Q factor (
P
= .039). Patient satisfaction was comparable between both groups.

CONCLUSIONS:

Both platforms were effective in correcting moderate myopia with or without astigmatism. No difference in refractive outcome, contrast sensitivity changes, and patient satisfaction between the groups was observed. Postoperatively, the tissue-saving method caused a higher increase in HOAs and Q factor compared to the wavefront-optimized method, which could be due to larger optical zone sizes in the tissue-saving group.

[
J Refract Surg.
2015;31(10):683–688.]
COMPARISON OF AN ELECTROMAGNETIC AND OPTICAL SYSTEM DURING DYNAMIC MOTION
Authors: Lugade Vipul , Chen Tzurei , Erickson Carl , Fujimoto Masahiro , Juan Jun G San , Karduna Andy , Chou Li-Shan
Published: September 2015

Few studies have concurrently investigated the accuracy and repeatability of an optical and electromagnetic (EM) system during dynamic motion. The purposes of this study were to: (1) assess the accuracy of both an EM and optical system when compared to a gold standard and (2) to compare the intra- and inter-day repeatability during 3D kinematic motion of both systems. The gold standard used for accuracy assessment was a robot programmed to manipulate a carbon fiber beam through pre-defined motions within the capture volume of both systems at 30, 45 and 60°/s. A total of 12 healthy young adults were tested for intra- and inter-day repeatability of hip, knee and ankle joint angles during a sit-to-stand movement. Marker trajectories were captured using an 8-camera Motion Analysis system and a Polhemus Liberty system. Optical markers for both portions of the study were precisely marked to allow for digitization by the EM system, with collections taken at 120 Hz. Accuracy and repeatability were assessed using the RMS error and coefficient of multiple correlations (CMC), respectively. The optical system demonstrated a 1–2.5° lower RMS error in tracking the robot movements in the transverse and sagittal planes when compared to the EM system. However, it was possible that metal interference affected the accuracy of the EM system. High intra-day and inter-day repeatability was demonstrated by both systems during the sit-to-stand task. The optical system did demonstrate slightly higher CMC values for between day trials, though skin motion artifact might have affected the EM system to a greater extent. Overall, both systems demonstrated an adequate ability to track dynamic motion.
HYBRID INTELLIGENT CONTROLLERS FOR A MULTIPLE DRUG DELIVERY SYSTEM IN ACUTE HEART FAILURE
Authors: Kashihara Koji
Published: September 2015

Regulating the dynamic responses to multiple therapeutic agents in cases of heart failure is difficult owing to time-variant changes in drug sensitivity and interaction. To address this problem, a multiple controller based on adaptive neural network (NN) predictive control has been developed for unexpected drug responses related to cardiac output and arterial pressure. However, the control speed may be slower than that in traditional controllers because of the real-time learning process for the NN. Moreover, a proportional-integral-derivative (PID) controller alone cannot automatically update the PID parameters during drug administration. This study, therefore, aimed to make hybrid intelligent (fuzzy or NN-based PID) controllers and to evaluate the control performance during multiple drug therapy in unexpected physiological responses of heart failure. The hybrid intelligent controllers were compared with the previous PID or NN controller, and they realized robust and quick control regardless of unexpected responses and acute disruptions.
A centre for community life in its fullness
Authors: Van Niekerk Attie
Published: September 2015

This article considers some theological reasons why there is a Centre for Sustainable Communities at the Faculty of Theology, University of Pretoria. The role of the Centre is discussed within the global and local search for sustainability; the world-wide trend in churches towards a missional approach, which emphasises the church�s life-giving role in all areas of life, and the theological reflection on the relationship between the church community and the civil community, so reflecting on the role of the local church to promote life in its fullness in the community. The Centre for Sustainable Communities (Centre) was established at the Faculty of Theology, University of Pretoria, in 2014. The Centre is intended to develop resources for local congregations to promote life in its fullness in local communities in southern Africa in an effective and meaningful way. In this article attention is given to the theological reasons for its establishment and where it is being positioned in the wider field of sustainability institutions. Attention will be given to the following:� The position of the Centre in the global search for sustainability.� Life in its fullness in the emerging 21st century missional paradigm.� The Christian community as agent of life in its fullness in the civil community.
A Simplified Parallel Two-Level Iterative Method for Simulation of Incompressible Navier-Stokes Equations
Authors: Shang Yueqiang , Qin Jin
Published: September 2015

Based on two-grid discretization, a simplified parallel iterative finite element method for the simulation of incompressible Navier-Stokes equations is developed and analyzed. The method is based on a fixed point iteration for the equations on a coarse grid, where a Stokes problem is solved at each iteration. Then, on overlapped local fine grids, corrections are calculated in parallel by solving an Oseen problem in which the fixed convection is given by the coarse grid solution. Error bounds of the approximate solution are derived. Numerical results on examples of known analytical solutions, lid-driven cavity flow and backward-facing step flow are also given to demonstrate the effectiveness of the method.
Comparison of Methods for Xenomonitoring in Vectors of Lymphatic Filariasis in Northeastern Tanzania
Authors: Irish Seth R. , Stevens William M. B. , Derua Yahya A. , Walker Thomas , Cameron Mary M.
Published: September 2015

Monitoring Wuchereria bancrofti infection in mosquitoes (xenomonitoring) can play an important role in determining when lymphatic filariasis has been eliminated, or in focusing control efforts. As mosquito infection rates can be low, a method for collecting large numbers of mosquitoes is necessary. Gravid traps collected large numbers of Culex quinquefasciatus in Tanzania, and a collection method that targets mosquitoes that have already fed could result in increased sensitivity in detecting W. bancrofti-infected mosquitoes. The aim of this experiment was to test this hypothesis by comparing U.S. Centers for Disease Control and Prevention (CDC) light traps with CDC gravid traps in northeastern Tanzania, where Cx. quinquefasciatus is a vector of lymphatic filariasis. After an initial study where small numbers of mosquitoes were collected, a second study collected 16,316 Cx. quinquefasciatus in 60 gravid trap-nights and 240 light trap-nights. Mosquitoes were pooled and tested for presence of W. bancrofti DNA. Light and gravid traps collected similar numbers of mosquitoes per trap-night, but the physiological status of the mosquitoes was different. The estimated infection rate in mosquitoes collected in light traps was considerably higher than in mosquitoes collected in gravid traps, so light traps can be a useful tool for xenomonitoring work in Tanzania.
Gut Microbiome Composition in Young Nicaraguan Children During Diarrhea Episodes and Recovery
Authors: Becker-Dreps Sylvia , Allali Imane , Monteagudo Andrea , Vilchez Samuel , Hudgens Michael G. , Rogawski Elizabeth T. , Carroll Ian M. , Zambrana Luis Enrique , Espinoza Felix , Azcarate-Peril M. Andrea
Published: September 2015

Understanding how the gut microbiota is affected by diarrhea episodes may help explain alterations in intestinal function among children in low-income settings. This study examined the composition of the gut microbiome of Nicaraguan children both during diarrhea episodes and while free of diarrhea for at least 2 months. Relative abundances of bacterial taxa, phylogenetic diversity, and species richness were determined by 16S amplicon sequencing and compared between paired diarrhea and recovery samples. A total of 66 stools were provided by 25 children enrolled in a 1-year cohort study of diarrhea etiologies. Children in our cohort had a mean age of 21.9 months; 64% were breast-fed, and 10% had received an antibiotic during the diarrhea episode. Overall, phylogenetic diversity and species richness did not differ significantly between diarrhea and recovery stools. However, of children who had a bacterial enteropathogen detected in any diarrhea stool, none experienced an increase in phylogenetic diversity in recovery, whereas of those in whom no bacterial enteropathogens were detected in their diarrhea stool(s), 59% experienced an increase in phylogenetic diversity in recovery (P = 0.008). This preliminary study suggests that recovery of the gut microbiota after a diarrhea episode may take longer time than previously thought and may be pathogen specific.
An Unusually Giant Hematoma threatening to the Laryngeal Airway
Authors: Swain Santosh Kumar , Samal Rankanidhi , Mohanty Sidhartha
Published: September 2015

An acute onset of giant laryngeal hematoma is rare and life-threatening condition. It occurs usually in patients with coagulo - pathies, often in those receiving warfarin. Various sites of bleeding have been reported in the literature, most commonly being the gastrointestinal tract, genitourinary tract and central nervous system. A large acute onset spontaneous hematoma is rarely reported in larynx. We report a case of an unusually large hematoma compromising the glottic airway in an over warfarinised patient. We highlight the need for a thorough evaluation of upper aerodigestive tract in patients on anticoagulant therapy. Detailed airway evaluation and monitoring with flexible laryngoscopy, and timely needful intervention are essential in above type of patients for preventing life-threatening consequences.

How to cite this article

Swain SK, Mohanty S, Singh N, Samal R. An Unusually Giant Hematoma threatening to the Laryngeal Airway. Int J Otorhinolaryngol Clin 2014;6(3):92-94.
Peripheral Giant Cell Reparative Granuloma of the Sino-orbital Region—A Giant Lesion: A Rare Case Report
Authors: Ashish Gaurav , Prabhu Anne Jenifer , Mani Sunithi
Published: September 2015

Peripheral giant cell reparative granulomas (PGCRGs) are benign tumors which spread locally and progress aggressively. The origin of the multinucleated giant cells is not established till date, and hence various theories suggesting the origin from osteoclasts based on the immunohistochemical features, or from mononuclear phagocyte system. The treatment of choice is surgical excision with adequate margins and the recurrence rates are usually below 10% as per the reported literature.1

We present a 6-year-old child who presented with a rapidly progressive sino-orbital mass leading to proptosis and lateral displacement of the right globe. He underwent combined approach (open and endoscopic assisted) for complete excision of the lesion. The histopathological features were consistent with PGCRG.

This case is being highlighted with the aim of developing insights about the clinical presentation and management of PGCRG.

How to cite this article

John M, Ashish G, Prabhu AJ, Mani S, Kurien M. Peripheral Giant Cell Reparative Granuloma of the Sino-orbital Region—A Giant Lesion: A Rare Case Report. Int J Otorhinolaryngol Clin 2014;6(3):109-113.
An Unusual Foreign Body of Eight Months Duration in the Nasopharynx of a Three Years Old Child
Authors: Agrahari Alok Kumar , Roy Suddhasheel , Jain Rajiv Kumar
Published: September 2015

A unique case of a 5 cm long impacted broken toothbrush in nasopharynx of a 3-year-old male child is being reported. The foreign body remained impacted for a long period of 8 months. The toothbrush was visualized transnasally by endoscopy and removed per oral under general anesthesia.

How to cite this article

Agrahari AK, Roy S, Jain RK. An Unusual Foreign Body of Eight Months Duration in the Nasopharynx of a Three Years Old Child. Int J Otorhinolaryngol Clin 2014;6(3): 140-141.
The Influence of pH on Localized Corrosion Behavior of X65 Carbon Steel in CO2-Saturated Brines
Authors: Pessu Frederick , Barker Richard , Neville Anne
Published: September 2015

Pitting and localized corrosion of carbon steel is considered to be a complex process influenced by a wide range of parameters such as temperature, bulk solution pH, and chloride ion concentration. Solution pH is known to influence corrosion product characteristics and morphology in CO2- and H2S-containing corrosion systems. However, from the perspective of pitting corrosion in CO2-saturated environments, the extent to which bulk pH of solutions and the presence of corrosion products influence localized attack is still not clearly understood. This paper presents an investigation into the role of pH on the characteristics of corrosion product and pitting corrosion behavior of X65 carbon steel (UNS K03014) in CO2-saturated brine. Pitting corrosion studies were conducted over 168 h at 50°C in 3.5 wt% NaCl solutions at different bulk pH (buffered to pH values of 6.6 and 7.5 in some cases) in order to understand and correlate the role of pH on corrosion product morphology, chemistry, initiation, and propagation of pits within each distinct environment. Corrosion product composition and morphology are identified through a combination of electrochemical and surface analysis techniques, which include scanning electron microscopy and x-ray diffraction. The extent of corrosion damage of the carbon steel is evaluated through the implementation of surface interferometry to study discrete pit geometry, namely the size, depth, and aspect ratio. Results indicate that the process of pit initiation and propagation of carbon steel in CO2 corrosion environment is different depending upon bulk solution pH. At low pH (pH values starting at 3.8), pitting initiates faster and propagates steadily along with significant uniform corrosion resulting from the formation of an “amorphous” form of FeCO3. At higher pH, uniform corrosion is significant, while pitting initiates with increasing protection from crystalline FeCO3. At a pH value of 7.5, pitting corrosion initiation occurs after and/or during pseudo-passivation is achieved as a result of the formation of a “protective and pseudo-passivating” FeCO3 film.
2015 Frank Newman Speller Award:
Stress Corrosion Cracking and Nuclear Power
Authors: Gorman J.A.
Published: September 2015

In order to provide background for a review of stress corrosion cracking (SCC) in nuclear power plants, a review is first presented of the history of occurrence of SCC in fossil fired power plants and a few related applications. The historical development of SCC in nuclear power plants is then described. The many materials and components that have been affected by SCC over the years are identified, as are the material, stress, and environmental factors involved. A particular focus of this monograph is the question of how it happened that materials with significant susceptibility to SCC were used for so many important structural applications in nuclear power plants. To address this question, the historical development of both pressurized water reactor designs and boiling water reactor designs is reviewed. The review covers factors such as the material types selected for test and use, the operating temperatures used as the designs evolved, and the qualification tests and prior operating experience that were relied upon for selection of materials. Some conclusions as to the factors involved in the choice of materials that turned out to be susceptible to SCC are presented, together with some suggestions for how to minimize such problems in the future.
Impact of 2050 climate change on North American wildfire: consequences for ozone air quality
Authors: Yue X. , Mickley L. J. , Logan J. A. , Hudman R. C. , Martin M. V. , Yantosca R. M.
Published: September 2015

Abstract. We estimate future area burned in the Alaskan and Canadian forest by the mid-century (2046–2065) based on the simulated meteorology from 13 climate models under the A1B scenario. We develop ecoregion-dependent regressions using observed relationships between annual total area burned and a suite of meteorological variables and fire weather indices, and apply these regressions to the simulated meteorology. We find that for Alaska and western Canada, almost all models predict significant (p < 0.05) increases in area burned at the mid-century, with median values ranging from 150 to 390 %, depending on the ecoregion. Such changes are attributed to the higher surface air temperatures and 500 hPa geopotential heights relative to present day, which together lead to favorable conditions for wildfire spread. Elsewhere the model predictions are not as robust. For the central and southern Canadian ecoregions, the models predict increases in area burned of 45–90 %. Except for the Taiga Plain, where area burned decreases by 50 %, no robust trends are found in northern Canada, due to the competing effects of hotter weather and wetter conditions there. Using the GEOS-Chem chemical transport model, we find that changes in wildfire emissions alone increase mean summertime surface ozone levels by 5 ppbv for Alaska, 3 ppbv for Canada, and 1 ppbv for the western US by the mid-century. In the northwestern US states, local wildfire emissions at the mid-century enhance surface ozone by an average of 1 ppbv, while transport of boreal fire pollution further degrades ozone air quality by an additional 0.5 ppbv. The projected changes in wildfire activity increase daily summertime surface ozone above the 95th percentile by 1 ppbv in the northwestern US, 5 ppbv in the high latitudes of Canada, and 15 ppbv in Alaska, suggesting a greater frequency of pollution episodes in the future atmosphere.
Turbulence vertical structure of the boundary layer during the afternoon transition
Authors: Darbieu C. , Lohou F. , Lothon M. , Vilà-Guerau de Arellano J. , Couvreux F. , Durand P. , Pino D. , Patton E. G. , Nilsson E. , Blay-Carreras E. , Gioli B.
Published: September 2015

Abstract. We investigate the decay of planetary boundary layer (PBL) turbulence in the afternoon, from the time the surface buoyancy flux starts to decrease until sunset. Dense observations of mean and turbulent parameters were acquired during the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field experiment by several meteorological surface stations, sounding balloons, radars, lidars and two aircraft during the afternoon transition. We analysed a case study based on some of these observations and large-eddy simulation (LES) data focusing on the turbulent vertical structure throughout the afternoon transition. The decay of turbulence is quantified through the temporal and vertical evolution of (1) the turbulence kinetic energy (TKE), (2) the characteristic length scales of turbulence and (3) the shape of the turbulence spectra. A spectral analysis of LES data, airborne and surface measurements is performed in order to characterize the variation in the turbulent decay with height and study the distribution of turbulence over eddy size. This study highlights the LES ability to reproduce the turbulence evolution throughout the afternoon. LESs and observations agree that the afternoon transition can be divided in two phases: (1) a first phase during which the TKE decays at a low rate, with no significant change in turbulence characteristics, and (2) a second phase characterized by a larger TKE decay rate and a change in spectral shape, implying an evolution of eddy size distribution and energy cascade from low to high wave number. The changes observed either in TKE decay (during the first phase) or in the vertical wind spectra shape (during the second phase of the afternoon transition) occur first in the upper region of the PBL. The higher within the PBL, the stronger the spectra shape changes.
Impact of climate and land cover changes on tropospheric ozone air quality and public health in East Asia between 1980 and 2010
Authors: Fu Y. , Tai A. P. K.
Published: September 2015

Abstract. Understanding how historical climate and land cover changes have affected tropospheric ozone in East Asia would help constrain the large uncertainties associated with future East Asian air quality projections. We perform a series of simulations using a global chemical transport model driven by assimilated meteorological data and a suite of land cover and land use data to examine the public health effects associated with changes in climate, land cover, land use, and anthropogenic emissions between the 5-year periods 1981–1985 and 2007–2011 in East Asia. We find that between these two periods land cover change alone could lead to a decrease in summertime surface ozone by up to 4 ppbv in East Asia and ~ 2000 fewer ozone-related premature deaths per year, driven mostly by enhanced dry deposition resulting from climate- and CO2-induced increase in vegetation density, which more than offsets the effect of reduced isoprene emission arising from cropland expansion. Climate change alone could lead to an increase in summertime ozone by 2–10 ppbv in most regions of East Asia and ~ 6000 more premature deaths annually, mostly attributable to warming. The combined impacts (−2 to +12 ppbv) show that while the effect of climate change is more pronounced, land cover change could offset part of the climate effect and lead to a previously unknown public health benefit. While the changes in anthropogenic emissions remain the largest contributor to deteriorating ozone air quality in East Asia over the past 30 years, we show that climate change and land cover changes could lead to a substantial modification of ozone levels, and thus should come into consideration when formulating future air quality management strategies. We also show that the sensitivity of surface ozone to land cover change is more dependent on dry deposition than on isoprene emission in most of East Asia, leading to ozone responses that are quite distinct from that in North America, where most ozone-vegetation sensitivity studies to date have been conducted.
Study of aerosol microphysical properties profiles retrieved from ground-based remote sensing and aircraft in-situ measurements during a Saharan dust event
Authors: Granados-Muñoz M. J. , Bravo-Aranda J. A. , Baumgardner D. , Guerrero-Rascado J. L. , Pérez-Ramírez D. , Navas-Guzmán F. , Veselovskii I. , Lyamani H. , Valenzuela A. , Olmo F. J. , Titos G. , Andrey J. , Chaikovsky A. , Dubovik O. , Gil-Ojeda M. , Alados-Arboledas L.
Published: September 2015

Abstract. In this work we present an analysis of mineral dust optical and microphysical properties obtained from different retrieval techniques applied to active and passive remote sensing measurements, including a comparison with simultaneous in-situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak a Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on the 27 June 2011. Column-integrated properties are provided by sun- and star-photometry which allows a continuous evaluation of the mineral dust optical properties during both day and night-time. Both the Linear Estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically-resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during night-time. LIRIC retrievals reveal several dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 μm3 cm−3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in-situ measurements. This study presents for the first time a comparison of both volume concentration and dust particle polarization ratios measured with in-situ and remote sensing techniques. Results for the depolarization measurements in the dust layer indicate reasonable agreement within the estimated uncertainties. The differences in the volume concentration profiles, although somewhat larger, are still within the expected uncertainties.
Time since death and decay rate constants of Norway spruce and European larch deadwood in subalpine forests determined using dendrochronology and radiocarbon dating
Authors: Petrillo M. , Cherubini P. , Fravolini G. , Ascher J. , Schärer M. , Synal H.-A. , Bertoldi D. , Camin F. , Larcher R. , Egli M.
Published: September 2015

Abstract. Due to the large size and highly heterogeneous spatial distribution of deadwood, the time scales involved in the coarse woody debris (CWD) decay of Picea abies (L.) Karst. and Larix decidua Mill. in Alpine forests have been poorly investigated and are largely unknown. We investigated the CWD decay dynamics in an Alpine valley in Italy using the five-decay class system commonly employed for forest surveys, based on a macromorphological and visual assessment. For the decay classes 1 to 3, most of the dendrochronological samples were cross-dated to assess the time that had elapsed since tree death, but for decay classes 4 and 5 (poorly preserved tree rings) and some others not having enough tree rings, radiocarbon dating was used. In addition, density, cellulose and lignin data were measured for the dated CWD. The decay rate constants for spruce and larch were estimated on the basis of the density loss using a single negative exponential model. In the decay classes 1 to 3, the ages of the CWD were similar varying between 1 and 54 years for spruce and 3 and 40 years for larch with no significant differences between the classes; classes 1–3 are therefore not indicative for deadwood age. We found, however, distinct tree species-specific differences in decay classes 4 and 5, with larch CWD reaching an average age of 210 years in class 5 and spruce only 77 years. The mean CWD rate constants were 0.012 to 0.018 yr−1 for spruce and 0.005 to 0.012 yr−1 for larch. Cellulose and lignin time trends half-lives (using a multiple-exponential model) could be derived on the basis of the ages of the CWD. The half-lives for cellulose were 21 yr for spruce and 50 yr for larch. The half-life of lignin is considerably higher and may be more than 100 years in larch CWD.
How past fire disturbances have contributed to the current carbon balance of boreal ecosystems?
Authors: Yue C. , Ciais P. , Zhu D. , Wang T. , Peng S. S. , Piao S. L.
Published: September 2015

Abstract. Boreal fires have immediate effects on regional carbon budgets by emitting CO2 into the atmosphere at the time of burning, but also have legacy effects by initiating a long-term carbon sink during post-fire vegetation recovery. Quantifying these different effects on the current-day pan-boreal (44–84° N) carbon balance and relative contributions of legacy sinks by past fires is important for understanding and predicting the carbon dynamics in this region. Here we used the global dynamic vegetation model ORCHIDEE-SPITFIRE to attribute the contributions by fires in different decades of 1850–2009 to the carbon balance of 2000–2009, taking into account the atmospheric CO2 change and climate change since 1850. The fire module of ORCHIDEE-SPITFIRE was turned off in each decade sequentially, and turned on before and after, to model the legacy carbon trajectory by fires in each past decade. We found that, unsurprisingly, fires that occured in 2000–2009 are a carbon source (−0.17 Pg C yr−1) for the 2000s-decade carbon balance, whereas fires in all decades before 2000 contribute carbon sinks with a collective contribution of 0.23 Pg C yr−1. This leaves a net fire sink effect of 0.06 Pg C yr−1, or 6.3 % of the simulated regional carbon sink (0.95 Pg C yr−1). Further, fires with an age of 10–40 years (i.e. those occurred during 1960–1999) contribute more than half of the total sink effect of fires. The small net sink effect of fires indicates that current-day fire emissions are roughly in balance with legacy sinks. The future role of fires in the regional carbon balance remains uncertain and will depend on whether changes in fires and associated carbon emissions will exceed the enhanced sink effects of previous fires, both being strongly affected by global change.
Microbial methanogenesis in the sulfate-reducing zone of surface sediments traversing the Peruvian margin
Authors: Maltby J. , Sommer S. , Dale A. W. , Treude T.
Published: September 2015

Abstract. We studied the concurrence of methanogenesis and sulfate reduction in surface sediments (0–25 cm below sea floor, cmbsf) at six stations (70, 145, 253, 407, 770 and 1024 m) along the Peruvian margin (12° S). This oceanographic region is characterized by high carbon export to the seafloor, creating an extensive oxygen minimum zone (OMZ) on the shelf, both factors that could favor surface methanogenesis. Sediments sampled along the depth transect traversed areas of anoxic and oxic conditions in the bottom-near water. Net methane production (batch incubations) and sulfate reduction (35S-sulfate radiotracer incubation) were determined in the upper 0–25 cmbsf of multicorer cores from all stations, while deep hydrogenotrophic methanogenesis (> 30 cmbsf, 14C-bicarbonate radiotracer incubation) was determined in two gravity cores at selected sites (78 and 407 m). Furthermore, stimulation (methanol addition) and inhibition (molybdate addition) experiments were carried out to investigate the relationship between sulfate reduction and methanogenesis. Highest rates of methanogenesis and sulfate reduction in the surface sediments, integrated over 0–25 cmbsf, were observed on the shelf (70–253 m, 0.06–0.1 and 0.5–4.7 mmol m−2 d−1, respectively), while lowest rates were discovered at the deepest site (1024 m, 0.03 and 0.2 mmol m−2 d−1, respectively). The addition of methanol resulted in significantly higher surface methanogenesis activity, suggesting that the process was mostly based on non-competitive substrates, i.e., substrates not used by sulfate reducers. In the deeper sediment horizons, where competition was probably relieved due to the decline of sulfate, the usage of competitive substrates was confirmed by the detection of hydrogenotrophic activity in the sulfate-depleted zone at the shallow shelf station (70 m). Surface methanogenesis appeared to be correlated to the availability of labile organic matter (C / N ratio) and organic carbon degradation (DIC production), both of which support the supply of methanogenic substrates. A negative correlation of methanogenesis rates with dissolved oxygen in the bottom-near water was not obvious, however, anoxic conditions within the OMZ might be advantageous for methanogenic organisms at the sediment–water interface. Our results revealed a high relevance of surface methanogenesis on the shelf, where the ratio between surface to deep (below sulfate penetration) methanogenic activity ranged between 0.13 and 105. In addition, methane concentration profiles indicate a partial release of surface methane into the water column as well as a partial consumption of methane by anaerobic methane oxidation (AOM) in the surface sediment. The present study suggests that surface methanogenesis might play a greater role in benthic methane budgeting than previously thought, especially for fueling AOM above the sulfate-methane transition zone.
A~compact receiver system for simultaneous measurements of mesospheric CO and O3
Authors: Forkman P. , M. Christensen O. , Eriksson P. , Billade B. , Vassilev V. , M. Shulga V.
Published: September 2015

Abstract. During the last decades, ground-based microwave radiometry has matured to an established remote sensing technique for measuring vertical profiles of a number of gases in the stratosphere and the mesosphere. Microwave radiometry is the only ground-based technique that can provide vertical profiles of gases in the upper stratosphere and mesosphere both day and night, and even during cloudy conditions. Except for microwave instruments placed at high altitude sites, or at sites with dry atmospheric conditions, only molecules with significant emission lines below 150 GHz, such as CO, H2O and O3 can be observed. Vertical profiles of these molecules can give important information about chemistry and dynamics in the middle atmosphere. Today these measurements are performed at relatively few sites, more simple and reliable instrument solutions are required to make the measurement technique more widely spread. This need is today urgent as the number of satellite sensors observing the middle atmosphere is about to decrease drastically. In this study a compact double-sideband frequency-switched radiometer system for simultaneous observations of mesospheric CO at 115.27 GHz and O3 at 110.84 GHz is presented The radiometer, its calibration scheme and observation method are presented. The retrieval procedure, including compensation of the different tropospheric attenuation at the two frequencies, and error characterization are also described. The first measurement series from October 2014 until April 2015 taken at the Onsala Space Observatory, OSO, (57° N, 12° E) is analysed. The retrieved vertical profiles are compared with co-located CO and O3 data from the MLS instrument on the Aura satellite. The datasets from the instruments agree well to each other. The main differences are the higher OSO volume mixing ratios of O3 in the upper mesosphere during the winter nights and the higher OSO volume mixing ratios of CO in the mesosphere during the winter. The low bias of mesospheric winter values of CO from MLS compared to ground-based instruments has been reported earlier.
Wind forcing and fate of Sardinella aurita eggs and larvae in the Sicily Channel (Mediterranean Sea)
Authors: Torri M. , Corrado R. , Falcini F. , Cuttitta A. , Palatella L. , Lacorata G. , Patti B. , Arculeo M. , Mazzola S. , Santoleri R.
Published: September 2015

Abstract. Multidisciplinary studies are recently seeking to define diagnostic tools for fishery sustainability by coupling ichthyoplanktonic datasets, physical and bio-geochemical oceanographic measurements, and ocean modelling. The main goal of these efforts is the understanding of those processes that control fate and dispersion of fish larvae and eggs and thus tune the inter-annual variability of biomass of fish species. We here analyzed eggs and larvae distribution and biological features of Sardinella aurita in the northeast sector of the Sicily Channel (Mediterranean Sea) collected during the 2010 and 2011 summer cruises. We make use of satellite sea surface temperature, wind, and chlorophyll data to recognize the main oceanographic patterns that mark eggs and larvae transport processes and we pair these data with Lagrangian runs. To provide a physical explanation of the transport processes that we observe, we hire a potential vorticity (PV) model that takes into account the role of wind stress in generating those cold filaments responsible for the offshore delivery of eggs and larvae. Our results show that the strong offshore transport towards Malta occurring in 2010 is related to a persistent wind forcing along the southern Sicilian coast that generated an observable cold filament. Such a pattern is not found in the 2011 analysis, which indeed shows a more favorable condition for sardinella larvae recruiting with a weak offshore transport. Our results want to add some insights regarding operational oceanography for sustainable fishery.