bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability and Reproducibility of Pigment Epithelial Detachment Volume Measurements in AMD Using a New Tool: ReVAnalyzer
Authors: Ohayon Avi , Semoun Oudy , Caillaux Violaine , Jung Camille , Lay Bruno , Miere Alexandra , Souied Eric H. , Blanco-Garavito Rocio
Published: October 2019

BACKGROUND AND OBJECTIVE:

To describe and present the reliability and reproducibility of a new software, Retinal Volume Analyzer (ReVAnalyzer), for pigment epithelium detachment (PED) volume quantification.

PATIENTS AND METHODS:

This is a retrospective study including patients with PEDs secondary to exudative age-related macular degeneration (AMD). Macular volume scans on spectral-domain optical coherence tomography on enhanced depth imaging mode were performed in all eyes. Image batches were then exported in .xml format to the ReVAnalyzer software. A semiautomated PED volume measurement was performed by three independent readers (RBG, VC, OS) twice, at the beginning and end of a 15-day period. Bland-Altman assessment for agreement was used to compare intra- and interobserver observations.

RESULTS:

Twenty eyes of 20 patients presenting with PED were analyzed. Bland-Altman analysis indicated a good agreement between inter- and intraobserver measurements. The intraclass correlation coefficient for intraobserver PED volume measurements and between the three observers (interobserver) was greater than 0.99, demonstrating high reproducibility and consistency of the methodology.

CONCLUSIONS:

ReVAnalyzer is a reliable tool that can assist in the analysis of PED volume with high reproducibility. This type of specific retinal volume analysis can be of help for monitoring disease activity and therapeutic response in AMD.

[
Ophthalmic Surg Lasers Imaging Retina
. 2019;50:e242–e249.]
Quarterly Anti-Vascular Endothelial Growth Factor Dosing for Neovascular Age-Related Macular Degeneration: Real-World Clinical Outcomes
Authors: Rusakevich Alexander M. , Zhou Brenda , Wong Tien P. , Wykoff Charles C.
Published: October 2019

BACKGROUND AND OBJECTIVE:

Characterize eyes managed with quarterly intravitreal anti-vascular endothelial growth factor injections for neovascular age-related macular degeneration (nAMD).

PATIENTS AND METHODS:

Treatment-naïve nAMD eyes managed predominately using a treat-and-extend approach that received five or more consecutive quarterly injections from 2005 to 2017.

RESULTS:

One hundred fifty eyes were retrospectively identified. During quarterly dosing, a mean of 9.8 injections were given over a mean of 29 months. Ninety-one eyes (61%) had no exudative disease recurrence during quarterly dosing. Thirty-three eyes (22%) experienced exudative activity recurrence, with a mean cumulative yearly recurrence rate of 12% and a mean 6-letter loss of visual acuity (VA). Twenty-four eyes (16%) stopped quarterly treatments; nine (38%) of these subsequently experienced exudative activity recurrence with a mean 8-letter VA loss.

CONCLUSION:

In this real-world analysis of nAMD managed with quarterly dosing over a mean of more than 2 years' follow-up, 22% experienced disease recurrence during quarterly dosing, and 38% of eyes that stopped quarterly dosing experienced subsequent exudative disease recurrence.

[
Ophthalmic Surg Lasers Imaging Retina
. 2019;50:e250–e256.]
Acoustic behavior of porous concrete. Characterization by experimental and inversion methods
Authors: Pereira M. , Carbajo J. , Godinho L. , Amado-Mendes P. , Mateus D. , Ramis J.
Published: October 2019

The use of porous concrete solutions with lightweight aggregates has become increasingly common in noise control due to their versatility in exterior and interior applications. In this work, samples of porous consolidated concrete with aggregates of expanded clay were produced, in order to study the influence of the grain size, thickness and water/aggregate/cement ratio on the sound absorption. Experimental techniques were used to obtain the surface impedance and sound absorption coefficient. In addition to experimental characterizations, an inverse method was used (based on a genetic algorithm) to obtain the macroscopic parameters capable of representing the materials studied through the theoretical model of Horoshenkov-Swift. Using the theoretical Horoshenkhov-Swift model it becomes possible to represent these materials in numerical models as equivalent fluids.
A Cross Examination of the Intention to Integrate MOOCs in Teaching and Learning: An Application of Multi- Group Invariance Analysis
Authors: Wong Kung-Teck , Abdullah Norazilawati Binti , Goh Pauline Swee Choo
Published: October 2019

This paper attempts to understand student teachers’ and practicing teachers’ integration of MOOCs in teaching and learning and build a model that pre-dicts the intention of integration of MOOCs among them. Five variables (performance expectancy (FE), effort expectancy (EE), social influence (SI), facilitating condition (FC) and behavioural intention(BI)) were selected to build a model for the study. Structural equation modelling (SEM) was used as the main technique for the data analysis. The suggested model was found reliable and valid, based on a self-reported survey of 135 student teachers and practicing teachers. Results showed that behavioural intention toward MOOCs was significantly explained by performance expectancy and facilitat-ing condition. Overall, of the four hypotheses, two were supported by the da-ta. Differences were, however, detected between student teachers and prac-ticing teachers in terms of SI and FC towards BI regards to MOOCs inten-tion of integration.
One-Stop Physics E-Book Package Development for Senior High School Learning Media
Authors: Adam Alif Syaiful , Suprapto Nadi
Published: October 2019

Many e-Book versions of Physics learning have used to support for gaining more information. Mostly, these e-Books didn’t contain virtual laboratory environment due to the student’s visualization in Physics concept. For this objection, an e-Book package was involved to developing, branded as Beboo (Bilingual e-Book), one stop e-Book package completed by physics visualize animation, virtual laboratory environment, student’s worksheet, supporting video and self-final test. Beboo uses to assist the second-year student in senior high school to learn static fluids concept, including of the condition in static fluids and the Pascal-Archimedes principle applying in an everyday situation. This e-Book was developed by a range of multimedia including text, pictures, diagrams, sound effect, music, video, and animation in interactive and effective elements and required multiskilling that are content crating and programming. Besides, it contains the interesting part in physics learning, a laboratory activity, designed in two simulators on U-Pipe and Hydraulic Lift due to the student’s understanding of the hydrostatic and pascal law systems. For a common self-final test, Beboo provides the final test feature, shown in multiple choice for concept achievement. In general, Beboo develops in three main stages (needs assessment, design and development & implementation) known as Hannafin and Peck Model and have the validation score in a range of 84%- 94%. Furthermore, Beboo should enlarge team due to more chapter coverage and Android platform support. Overall, Beboo uses for an alternative use for school with no real laboratory and as the minimal point to the next e-Book development. Moreover, this media developed as the answer in technology integration in 21st-century learning.
Effect of Jigsaw Strategy and Learning Style to Conceptual Understanding on Senior High School Students
Authors: Kade Amiruddin , Degeng I Nyoman Sudana , Ali Muhammad Nur
Published: October 2019

Conceptual understanding should have serious attention due to the low score of Physics subject on national examination in Palu. The difference between learning style and jigsaw strategy is able to combine abstract conceptualization and active experiment towards the conceptual understanding for students whose learning style is converger and diverger. The research design was quasi experiment. The sample is the eleventh class of Senior High School students in Palu that are chosen using cluster random sampling (multistage), that is, 167 students. The research instrument was Kolb’s Learning Style Inventory (KLSI) of conceptual understanding test on Physics (Tes Pemahaman Konsep Fisika or TPKF). The data was analyzed by using ANOVA, with the significant level is 5%. The result shows that: (1) cooperative learning strategy of jigsaw type has more benefits than direct learning strategy in conceptual understanding on Physics, (2) student group of which learning style was converger has higher conceptual understanding than that of which learning style was diverger, (3) there are interaction influence between learning strategy and learning style towards the conceptual understanding on Physics
La place Fontainas comme espace frontière. La production de la ville au regard de la sexualité, du genre, de l’ethnicité et de la classe sociale
Authors: Donnen Alexandre
Published: October 2019

Située entre le quartier « gay » et le quartier « populaire » Anneessens, la place Fontainas a été le lieu de plusieurs actes de violence prétendument homophobes, contribuant à la catégoriser comme un espace d’insécurité, particulièrement pour les populations homosexuelles. En réponse à ce type de violences, les mesures adoptées par les instances publiques se multiplient mais peinent néanmoins à sortir d’une logique sécuritaire, souvent binaire et essentialisante. À partir d’un travail d’observation directe et d’entretiens sur et autour de la place Fontainas, le présent article entend adopter une nouvelle approche. Il appréhende cet espace à partir de la notion de frontière et, à travers une analyse intersectionnelle, rend compte des mécanismes socio-urbains qui participent à établir des ruptures en termes de sexualité, de classe sociale et d’ethnicité. Par contre, dans chacune des zones étudiées, la continuité de la domination masculine invisibilise et contraint l’accès des femmes à l’espace public.
Analysis of facing materials used as remoistenable temporary supports for facing on canvas paintings
Authors: Alba Paola , Martín-Rey Susana , Doménech-Carbó MaríaTeresa
Published: October 2019

L’article analyse de manière critique les techniques de facing et la description d’un système novateur fondé sur l’usage de supports temporaires réhumidifiable qui vont permettre d’obtenir une protection superficielle avec une force de liaison appropriée et facilement réversible. Cet article comprend aussi la description de la première partie expérimentale de l’enquête, focalisée sur l’évaluation des caractéristiques des différentes catégories de matériaux (adhésifs et supports temporaires) et leur combinaison pour la réalisation de supports temporaires réhumidifiable.
Determining Appropriate Preservation Conditions for Historical Mixed-Media Objects: a Risk-Based Approach
Authors: Anaf Willemien , Debulpaep Marjolijn
Published: October 2019

Les objets composites historiques sont constitués d’une large série de matériaux organiques et/ou inorganiques. Ils sont souvent fragiles en raison de la nature des matériaux utilisés et de leur état de dégradation avancé. Leurs conditions de conservation doivent faire l’objet d’un choix réfléchi afin de ralentir leur dégradation. Chaque matériau ayant ses exigences spécifiques, il est difficile de donner des recommandations de conservation préventive. Pour appuyer la décision, une approche basée sur la gestion des risques est développée. La méthodologie proposée (1) offre une base objective pour dégager des compromis concernant les conditions de préservation et (2) permet la comparaison de différents scénarios afin de sélectionner le plus approprié. Dans un premier temps, la méthodologie est expliquée de manière théorique. Une étude de cas sur un jardin clos médiéval permet ensuite d’illustrer ces deux aspects.
Matera Building Stones: Comparison between Bioclastic and Lithoclastic Calcarenites
Authors: Bonomo Agnese Emanuela , Lezzerini Marco , Prosser Giacomo , Munnecke Axel , Koch Roman , Rizzo Giovanna
Published: October 2019

Matera (Basilicata, southern Italy) was awarded World Heritage Site status by the UNESCO since 1993, and it will be the European Capital of Culture in 2019. It is one of the most ancient towns in the world, whose historical centre was totally built by only a moderately lithified and highly porous sedimentary building stone, known as Gravina Calcarenite. This easily workable rock was quarried since prehistoric times, and it was used for building different kind of constructions from the rupestrian settlement to the gorgeous historic palace during the XVIII century. Calcarenite, however, can be an extremely heterogeneous building material depending on the composition of the particles and their characteristics. After a geological survey, it was possible to recognize two main varieties of this building stone, which were in turn subdivided into six sub-typologies. As a first approach, we have characterized, in terms of building stone quality, the two main varieties: the bioclastic calcarenite and the lithoclastic calcarenite, sampled in the quarrying area to the North of Matera. The bioclastic calcarenite is from a new quarry in the upper part of the Calcarenite Formation, while the lithoclastic calcarenite is from an old quarry, inactive since 1965, in the lower part of the same formation. Mineralogical, petrographic and petrophysical tests have been carried out according to European Standards rules to highlight the main characteristics of different calcarenite types when used as building stone. Despite of their compositional differences, the bioclastic and lithoclastic calcarenite are both pure limestones with slightly different amounts of non-carbonates (silt quartz, clay minerals). The slightly different but characteristic mechanical properties clearly characterize the primary influence of grain composition, early cementation and micrite contents.
STAT3 Inhibition Partly Abolishes IL-33–Induced Bone Marrow–Derived Monocyte Phenotypic Transition into Fibroblast Precursor and Alleviates Experimental Renal Interstitial Fibrosis
Authors: Zhu Fengge , Bai Xueyuan , Hong Quan , Cui Shaoyuan , Wang Xu , Xiao Fengjun , Li Jin , Zhang Li , Dong Zheyi , Wang Yong , Cai Guangyan , Chen Xiangmei
Published: October 2019

Previous studies of Jak–STAT inhibitors have shown promise in treating kidney diseases. The activation of Jak–STAT components is important in cell fate determination in many cell types, including bone marrow–derived cells, which are important contributors in renal interstitial fibrosis. In this study, we tested the effect of a new STAT3 inhibitor, BP-1-102, on monocyte-to-fibrocyte transition and the progression of renal interstitial fibrosis. We tested the effect of BP-1-102 in a mouse model of unilateral ureteral obstruction in vivo and IL-33-treated bone marrow–derived monocytes in vitro. BP-1-102 treatment alleviated renal interstitial fibrosis, reduced collagen deposition and extracellular matrix protein production, inhibited inflammatory cell infiltration, suppressed the percentage of CD45+ PDGFRβ+, CD45+ CD34− Col I+ and CD45+ CD11b+ Col I+ cells within the obstructed kidney and reduced the mRNA levels of the proinflammatory and profibrotic cytokines IL-1β, TGF-β, TNF-α, ICAM-1, and CXCL16. In vitro, BP-1-102 inhibited the IL-33–induced phenotypic transition into fibroblast precursors in bone marrow–derived monocytes, marked by reduced CD45+ CD34− Col I+ and CD45+ CD11b+ Col I+ cell percentage. Our results indicate a potential mechanism by which the STAT3 inhibitor BP-1-102 inhibits bone marrow–derived monocyte transition into fibroblast precursors in an IL-33/STAT3–dependent manner and thereby alleviates renal interstitial fibrosis.
The role of heart rate and ivabradine in acute heart failure
Authors: Sciatti Edoardo , Vizzardi Enrico , Bonadei Ivano , Dallapellegrina Lucia , Carubelli Valentina
Published: October 2019

Resting heart rate (HR) is considered a powerful predictor of mortality both in healthy subjects and in cardiovascular (CV) patients, including those affected by heart failure (HF). Its reduction below 70 bpm is the treatment target in chronic HF with reduced ejection fraction (HFrEF) when sinus rhythm is present. In acute HF (AHF) HR is usually elevated but its role as risk marker is still unknown. Notably, in unstable patients, beta-blockers can be reduced or stopped, thus enhancing this phenomenon. Moreover, some data in literature suggest that HR reduction during hospitalization or HR at discharge or in the vulnerable phase after it are more predictive of early-term events and may be therapeutic targets. On the other hand, ivabradine is a pure HR-lowering drug with no effects on inotropism. Its role in the AHF setting has been recently investigated and is the object of this review.
Developmental dyslexia: a condensed review of literature
Authors: Kuerten Anna Belavina , Mota Mailce Borges , Segaert Katrien
Published: October 2019

In this article we provide a condensed review of literature on developmental dyslexia. Starting with the historical background to this language-based reading disorder, we discuss four key components that are crucial for a valid and operational definition of developmental dyslexia. We then present the major theoretical explanations of developmental dyslexia in order to gain a better understanding of the causes of this reading disorder. These causal explanations are addressed in the context of Morton and Frith’s (1995) model. Four major theories of developmental dyslexia are discussed: the phonological deficit theory, the double-deficit theory, the magnocellular theory, and the cerebellar theory. The last section of this review addresses the model of reading development proposed by Frith (1986). Understanding the developmental progression of children’s abilities in reading is crucial in order to detect in which phase of this progression a breakdown attributed to dyslexia occurs.
The negative evidence hypothesis: the acquisition of the double-object construction by Brazilian-Portuguese English bilinguals
Authors: Oliveira Cândido , Penzin Alberto
Published: October 2019

This study aims to add to the body of evidence regarding the linguistic structures that seem to be more challenging in L2 acquisition than in L1 acquisition (DeKeyser, 2005; Ellis, 2008; Inagaki, 2001; Slabakova, 2014; Sorace, 2011). The Negative Evidence Hypothesis (NEH) (AUTHOR) predicts that bilinguals are less sensitive than native speakers to violations resulted from the overgeneralization of an L2-specific rule. We tested this hypothesis by analyzing the behavior of Brazilian Portuguese-English bilinguals with different profiles towards double-object construction with unlicensed verbs in two acceptability judgment tasks. The results corroborate the NEH by conveying that bilinguals gain sensitivity as they become more proficient, yet, the data suggests that not even when immersed in the L2, they become as sensitive as native speakers.
When knowing a grammar rule makes L2 users non-native-like
Authors: Santos Clarice Fernandes dos , Souza Ricardo Augusto de , Ciríaco Larissa Santos
Published: October 2019

In this work, we investigate the effects of transfer of training in late Brazilian Portuguese-English bilinguals, compared to natives, in relation to their processing of the English causative-have construction. Two experiments were conducted: one focused on the comprehension of the pattern, and the other focused on its production. The results of both experiments point to the fact that the grammatical rule learned by bilinguals is only 'transferred' when there is time to implement it. In the first experiment, we found no effect of training, on the contrary, bilinguals might have been affected by the SVO distribution of the corresponding construction in their L1. In the second experiment, however, we found that bilinguals had high rates of usage of the canonical causative-have form, SAuxOV. This behavior indicates that bilinguals do not implement the rule automatically. Rather, its implementation is seen in more controlled tasks. Thus, explicitly given grammatical rules seem not to be implicitly learned, as they are not automatized to be easily retrieved in real life usage. Moreover, concerning the causative-have rule, bilinguals' linguistic behavior was more similar to that of natives' when they did not implement the rule and used the SVO form with a causative sense.
De dissonâncias e traduções: territorialidades e gestões no alto rio Negro.
Authors: Iubel Aline Fonseca
Published: October 2019

Desde antes da demarcação das primeiras terras indígenas no alto rio Negro (há mais de vinte anos), população e lideranças indígenas regionais atuam constantemente em processos de reflexão e avaliação de algumas de suas experiências de gestão territorial e relações com o Estado. Atualmente, desenvolvem essas atividades com os instrumentos da Política Nacional de Gestão Ambiental e Territorial de Terras Indígenas (PNGATI). Refletir a partir de algumas das dissonâncias e traduções implicadas nas relações entre indígenas e Estado no tocante às territorialidades e às gestões das mesmas (que envolvem também, evidentemente, a gestão da própria relação que se quer estabelecer com o Estado, do ponto de vista indígena) é o principal objetivo deste artigo.
Mexico
Authors:   International Monetary Fund. Western Hemisphere Dept.
Published: October 2019

This Selected Issues paper analyzes transmission of monetary policy rates to lending and deposit rates in Mexico. The results show that transmission of the policy rate to market rates is statistically significant in all cases, except for mortgage rates. For sight deposits, pass-through is low, with a 1 percentage point increase in the policy rate leading to a 0.2 percentage point rise in the deposit rate. For term deposits the pass-through is stronger, but remains below unity at 0.7. The pass-through to both lending and deposit rates is very rapid. The dynamic specifications show that pass-through is significant in either the current or the following month, and the long-term impact is achieved during the second month.
Food and Fuel Prices - Recent Developments, Macroeconomic Impact, and Policy Responses
Authors:   International Monetary Fund
Published: October 2019

This report provides a first broad assessment of the impact of the surge in food and fuel prices on the balance of payments, budgets, prices, and poverty of a large sample of countries. It reviews countries’ macroeconomic policy responses to date and also discusses Fund advice for managing the price increases. Policies should (i) ensure that food and finance reaches the most affected countries as quickly as possible, (ii) include targeted and scaled-up social measures, and (iii) avoid high costs in terms of macroeconomic instability or loss in future agricultural production. Collaborating with international partners, the Fund also stands ready to provide balance of payments assistance. As the paper presents an initial assessment of a still-evolving situation, the somewhat tentative nature of the analysis should be borne in mind.
Review of Data Provision to the Fund for Surveillance Purposes
Authors:   International Monetary Fund
Published: October 2019

This paper reviews how well members are providing the data the Fund needs, how well staff is handling issues of data inadequacy, and how the Fund’s data needs are evolving. The aim is to identify possible ways of improving data provision or, where data provision can only improve as the result of protracted capacity building, to ensure that surveillance takes due account of data inadequacies.
Relative impact of aerosol, soil moisture, and orography perturbations on deep convection
Authors: Schneider Linda , Barthlott Christian , Hoose Corinna , Barrett Andrew I.
Published: October 2019

Abstract. The predictability of deep moist convection depends on many factors, such as the synoptic-scale flow, the geographical region (i.e., the presence of mountains), and land surface–atmosphere
as well as aerosol–cloud interactions. This study addresses all these factors by investigating the relative impact of orography, soil moisture, and aerosols on
precipitation over Germany in different weather regimes. To this end, we conduct numerical sensitivity studies with the COnsortium for Small-sale MOdelling (COSMO) model
at high spatial resolution (500 m grid spacing) for 6 days with weak and strong synoptic forcing. The numerical experiments consist of (i) successive smoothing of topographical features,
(ii) systematic changes in the initial soil moisture fields (spatially homogeneous increase/decrease, horizontal uniform soil moisture, different realizations of dry/wet patches),
and (iii) different assumptions about the ambient aerosol concentration (spatially homogeneous and heterogeneous fields).
Our results show that the impact of these perturbations on precipitation is on average higher for weak than for strong synoptic forcing.
Soil moisture and aerosols are each responsible for the maximum precipitation response for three of the cases, while the sensitivity to terrain forcing
always shows the smallest spread. For the majority of the analyzed cases, the model produces a positive soil moisture–precipitation feedback when averaged over the entire model domain.
Furthermore, the amount of soil moisture affects precipitation more strongly than its spatial distribution. The precipitation response to changes in the CCN concentration is more complex and case dependent.
The smoothing of terrain shows weaker impacts on days with strong synoptic forcing because surface fluxes are less important and orographic ascent is still simulated reasonably well, despite missing
fine-scale orographic features. We apply an object-based characterization to identify whether and how the perturbations affect the structure, location, timing, and intensity of precipitation.
These diagnostics reveal that the structure component, comparing the size and shape of precipitating objects to the reference simulation, is on average highest in the soil moisture and aerosol
simulations, often due to changes in the maximum precipitation amounts. This indicates that the dominant mechanisms for convection initiation remain but that precipitation amounts
depend on the strength of the trigger mechanisms. Location and amplitude parameters both vary over a much smaller range. Still, the temporal evolution of the amplitude component correlates
well with the rain rate. Our results suggest that for quantitative precipitation forecasting, both aerosols and soil moisture are of similar importance
and that their inclusion in convective-scale ensemble forecasting containing classical sources of uncertainty should be assessed in the future.
Technical note: Effects of uncertainties and number of data points on line fitting – a case study on new particle formation
Authors: Mikkonen Santtu , Pitkänen Mikko R. A. , Nieminen Tuomo , Lipponen Antti , Isokääntä Sini , Arola Antti , Lehtinen Kari E. J.
Published: October 2019

Abstract. Fitting a line to two measured variables is considered
one of the simplest statistical procedures researchers can carry out. However, this
simplicity is deceptive as the line-fitting procedure is actually quite a
complex problem. Atmospheric measurement data never come without some
measurement error. Too often, these errors are neglected when researchers
make inferences from their data. To demonstrate the problem, we simulated datasets with different numbers of
data points and different amounts of error, mimicking the dependence of the atmospheric new particle
formation rate (J1.7) on the sulfuric acid concentration
(H2SO4). Both variables have substantial measurement error and, thus, are good test variables for our study. We show that ordinary least
squares (OLS) regression results in strongly biased slope values compared
with six error-in-variables (EIV) regression methods (Deming regression, principal component analysis, orthogonal regression, Bayesian EIV and two different bivariate
regression methods) that are known to take errors in the variables into account.
Evidence of small-scale quasi-isentropic mixing in ridges of extratropical baroclinic waves
Authors: Kunkel Daniel , Hoor Peter , Kaluza Thorsten , Ungermann Jörn , Kluschat Björn , Giez Andreas , Lachnitt Hans-Christoph , Kaufmann Martin , Riese Martin
Published: October 2019

Abstract. Stratosphere–troposphere exchange within extratropical cyclones provides
the potential for anthropogenic and natural surface emissions to rapidly
reach the stratosphere as well as for ozone from the stratosphere to
penetrate deep into the troposphere, even down into the boundary layer.
The efficiency of this process directly influences the surface climate,
the chemistry in the stratosphere, the chemical composition of the
extratropical transition layer, and surface pollution levels.
Here, we present evidence for a mixing process within extratropical
cyclones which has gained only a small amount of attention so far and which fosters
the transport of tropospheric air masses into the stratosphere in ridges
of baroclinic waves.
We analyzed airborne measurement data from a research flight of the WISE
(Wave-driven ISentropic Exchange) campaign over the North Atlantic in
autumn 2017, supported by forecasts from a numerical weather prediction
model and trajectory calculations.
Further detailed process understanding is obtained from experiments of
idealized baroclinic life cycles.
The major outcome of this analysis is that air masses mix in the region
of the tropopause and potentially enter the stratosphere in ridges of
baroclinic waves at the anticyclonic side of the jet without changing their
potential temperature drastically.
This quasi-isentropic exchange occurs above the outflow of warm conveyor
belts, in regions which exhibit enhanced static stability in the lower
stratosphere and a Kelvin–Helmholtz instability across the tropopause.
The enhanced static stability is related to radiative cooling below the
tropopause and the presence of small-scale waves.
The Kelvin–Helmholtz instability is related to vertical shear of the
horizontal wind associated with small-scale waves at the upper edge of the
jet stream.
The instability leads to the occurrence of turbulence and consequent
mixing of trace gases in the tropopause region.
While the overall relevance of this process has yet to be assessed, it
has the potential to significantly modify the chemical composition of
the extratropical transition layer in the lowermost stratosphere in
regions which have previously gained a small amount of attention in terms of
mixing in baroclinic waves.
Supercooled Drizzle Development in Response to Semi-Coherent
Vertical Velocity Fluctuations Within an Orographic Layer Cloud
Authors: Majewski Adam , French Jeffrey R.
Published: October 2019

Abstract. Observations of super-cooled liquid water are nearly ubiquitous within wintertime, orographic layer clouds over the intermountain west; however, observations of regions containing super-cooled drizzle drops (SCDDs) are much rarer and the factors controlling SCDD development and location less well understood. As part of the Seeded and Natural Orographic Wintertime clouds – the Idaho Experiment (SNOWIE) goal of improving understanding of natural cloud structure, this study examines the role of fine-scale (sub-kilometer) vertical velocity fluctuations on the microphysical evolution and location of SCDDs within the observed mixed-phase, wintertime orographic clouds from one research flight of SNOWIE. This flight saw SCDDs develop in an elevated, postfrontal layer cloud with cold cloud tops (T
Simulation of convective moistening of extratropical lower stratosphere using a numerical weather prediction model
Authors: Qu Zhipeng , Huang Yi , Vaillancourt Paul A. , Cole Jason N. S. , Milbrandt Jason A. , Yau Man Kong , Walker Kaley , de Grandpré Jean
Published: October 2019

Abstract. Stratospheric water vapor (SWV) is a climatically important atmospheric constituent due to its impacts on the radiation budget and atmospheric chemical composition. Despite the important role of SWV in the climate system, the processes controlling the distribution and variation of water vapor in the upper troposphere and lower stratosphere (UTLS) are not well understood. In order to better understand the mechanism of transport of water vapor through the tropopause, this study uses the high resolution Global Environmental Multiscale model of the Environment and Climate Change Canada, to simulate a lower stratosphere moistening event over North America. Satellite remote sensing and aircraft in situ observations are used to evaluate the quality of model simulation. The main focus of this study is to evaluate the processes that influence the lower stratosphere water vapor budget, particularly the direct water vapor transport and the moistening due to the ice sublimation. In the high-resolution simulations with horizontal grid-spacing less than 2.5 km, it is found that the main contribution to lower-stratospheric moistening is the upward transport caused by the breaking of gravity waves. In contrast, for the lower-resolution simulation with horizontal grid-spacing of 10 km, the lower-stratospheric moistening is dominated by the sublimation of ice. In comparison with the aircraft in situ observations, the high-resolution simulations predict well the water vapor content in the UTLS, while the lower resolution simulation over-estimates the water vapor content. This overestimation is associated with the overly abundant ice in the UTLS along with too-high sublimation rate in the lower stratosphere. The results of this study affirm the strong influence of overshooting convection on the lower-stratospheric water vapor and highlight the importance of both dynamics and microphysics in simulating the water vapor distribution in the UTLS region.
Effects of Black Carbon Mitigation on Arctic Climate
Authors: Kühn Thomas , Kupiainen Kaarle , Miinalainen Tuuli , Kokkola Harri , Paunu Ville-Veikko , Laakso Anton , Tonttila Juha , Van Dingenen Rita , Kulovesi Kati , Karvosenoja Niko , Lehtinen Kari E. J.
Published: October 2019

Abstract. We use the aerosol-climate model ECHAM-HAMMOZ to assess the effects of black carbon (BC) mitigation measures on Arctic climate. To this end we constructed several mitigation scenarios that implement all currently existing legislation and then implement further reductions of BC in a successively increasing global area, starting from the eight member states of the Arctic Council, expanding to its active observer states, then to all observer states, and finally to the entire globe. These scenarios also account for the reduction of the co-emitted organic carbon (OC) and sulphate (SU). We find that, even though the additional BC emission reductions in the member states of the Arctic Council are small, the resulting reductions in Arctic BC mass burdens can be substantial, especially in the lower atmosphere close to the surface. This in turn means that reducing BC emissions only in the Arctic Council member states can reduce BC deposition in the Arctic by about 30 % compared to the current legislation, which is about 60 % of what could be achieved if emissions were reduced globally. Emission reductions further south affect Arctic BC concentrations at higher altitudes and thus only have small additional effects on BC deposition in the Arctic. The direct radiative forcing scales fairly well with the total amount of BC emission reduction, independent of the location of the emission source, with a maximum direct radiative forcing in the Arctic of about 0.4 W/m2 for a global BC emission reduction. On the other hand, the Arctic effective radiative forcing due to the BC emission reductions, which accounts for aerosol-cloud interactions, is small compared to the direct aerosol radiative forcing. This happens because BC and OC containing particles can act as cloud condensation nuclei, which affects cloud reflectivity and lifetime, and counter-acts the direct radiative forcing of BC. Additionally the effective radiative forcing is accompanied by very large uncertainties that origin from the strong natural variability of meteorology, cloud cover, and surface albedo in the Arctic. We further used the model TM5-FASST to assess the benefits of the aerosol emission reductions on human health. We found that a full implementation in all Arctic Council member and observer states could reduce the annual global amount of premature deaths by 339 000 by 2030.
Free-fall experiments of volcanic ash particles using a 2-D video disdrometer
Authors: Suh Sung-Ho , Maki Masayuki , Iguchi Masato , Lee Dong-In , Yamaji Akihiko , Momotani Tatsuya
Published: October 2019

Abstract. Information of aerodynamic parameters of volcanic ash particles, such as
terminal velocity, axis ratio, and canting angle, are necessary for
quantitative ash-fall estimations with weather radar. In this study,
free-fall experiments of volcanic ash particles were accomplished using a
two-dimensional video disdrometer under controlled conditions. Samples containing a rotating symmetric axis were selected and divided into
five types according to shape and orientation: oblate spheroid with
horizontal rotating axis (OH), oblate spheroid with vertical axis (OV),
prolate spheroid with horizontal rotating axis (PH), prolate spheroid with
vertical rotating axis (PV), and sphere (Sp). The horizontally (OH and PH)
and vertically (OV and PV) oriented particles were present in proportions of
76 % and 22 %, and oblate and prolate spheroids were in proportions of
76 % and 24 %, respectively. The most common shape type was OH (57 %). The terminal velocities of OH, OV, PH, PV, and Sp were obtained analyzing
2-D video disdrometer data. The terminal velocities of PV were highest compared to those of
other particle types. The lowest terminal velocities were found in OH
particles. It is interesting that the terminal velocities for OH decreased
rapidly in the range 0.5<D<1 mm, corresponding to the
decrease in axis ratio (i.e., smaller the particle, the flatter the shape).
The axis ratios of all particle types except Sp were found to be converged
to 0.94 at D>2 mm. The histogram of canting angles followed unimodal and bimodal distributions
with respect to horizontally and vertically oriented particles,
respectively. The mean values and the standard deviation of entire particle
shape types were close to 0 and 10∘, respectively,
under calm atmospheric conditions.
A new lidar inversion method using a surface reference target.
Application to the backcattering coefficient and lidar ratio retrievals
of a fog-oil plume at short-range
Authors: Gaudfrin Florian , Pujol Olivier , Ceolato Romain , Huss Guillaume , Riviere Nicolas
Published: October 2019

Abstract. In this paper, a new elastic lidar inversion equation is presented. It is based on the backscattering signal from a surface reference target (SRT) rather than that from a volumetric layer of reference (Rayleigh molecular scatterer) as usually done. The method presented can be used when the optical properties of such a layer are not available, e.g. in the case of airborne elastic lidar measurements or when the lidar-target line is horizontal. Also, a new algorithm is described to retrieve the lidar ratio and the backscattering coefficient of an aerosol plume without any a priori assumptions about the plume. In addition, our algorithm allows a determination of the instrumental constant. This algorithm is theoretically tested, viz. by means of simulated lidar profiles, and then using real measurements. Good agreement with available data in the literature has been found.
Effect of aerosol composition on the performance of low-cost optical particle counter correction factors
Authors: Crilley Leigh R. , Singh Ajit , Kramer Louisa J. , Shaw Marvin D. , Alam Mohammed S. , Apte Joshua S. , Bloss William J. , Hildebrandt Ruiz Lea , Fu Pingqing , Fu Weiqi , Gani Shahzad , Gatari Michael , Ilyinskaya Evgenia , Lewis Alastair C. , Ng'ang'a David , Sun Yele , Whitty Rachel C. W. , Yue Siyao , Young Stuart , Pope Francis D.
Published: October 2019

Abstract. There is considerable interest in using low-cost optical particle counters (OPC) to supplement existing routine air quality networks that monitor particle mass concentrations. In order to do this, low-cost OPC data needs to be cross-comparable with particle mass reference instrumentation, and as yet, there is no widely agreed methodology. Aerosol hygroscopicity is known to be a key parameter to consider when correcting particle mass concentrations derived from a low-cost OPC, particularly at high ambient Relative Humidity (RH). Correction factors have been developed that apply κ-Köhler theory to correct for the influence of water uptake by hygroscopic aerosols. We have used datasets of co-located reference particle measurements and a low-cost OPC (OPC-N2, Alphasense), collected in four cities in three continents, to explore the performance of this correction factor. We report evidence that the elevated particle mass concentrations, reported by the low-cost OPC relative to reference instrumentation, is due to bulk aerosol hygroscopicity under different RH conditions, which is determined by aerosol composition and in particular the levels of hygroscopic aerosols (sulphate and nitrate). We exploit measurements made in volcanic plumes in Nicaragua, that are predominantly composed of sulphate aerosol, as a natural experiment to demonstrate this behaviour in the ambient atmosphere, with the observed humidogram closely resembling the calculated pure sulphuric acid humidogram. The results indicate that the particle mass concentrations derived from low-cost OPCs during periods of high RH (> 60 %) need to be corrected for aerosol hygroscopic growth. We employed a correction factor based on κ-Köhler theory and observed corrected OPC-N2 PM2.5 mass concentrations to be within 33 % of reference measurements at all sites. The results indicated that an in situ derived κ (using suitable reference instrumentation) would lead to the most accurate correction relative to co-located reference instruments. Applying literature κ in the correction factor also resulted in improved performance of OPC-N2, to be within 50 % of reference. Therefore, for areas where suitable reference instrumentation for developing a local correction factor is lacking, using a literature κ value can result in a reasonable correction. For locations with low levels of hygroscopic aerosols and RH, a simple calibration against gravimetric measurements (using suitable reference instrumentation) would likely be sufficient. Whilst this study generated correction factors specific for the Alphasense OPC-N2 sensor, the calibration methodology developed is likely amenable to other low cost PM sensors.
Evaluation of Possible Corrosion Enhacement Due to Telluric Currents: Case Study for Brazilian Pipeline
Authors: Fernandes de Moraes Joyrles , Paulino Igo , Alves Livia , Marcos Dinardini Clezio
Published: October 2019

Abstract. Electric field induced in the Brazil–Bolivia pipeline was calculated using a distributed source line transmission (DSLT) theory during several space weather events. It was made with using geomagnetic data collected by a fluxgate magnetometer located at São José dos Campos (23.2º S; 45.9º W). The total corrosion rate was calculated with using the Gummow (2002) methodology and based in the assumption of 1-cm hole in pipeline coating. The calculations were performed for the ends of pipeline, where the largest out of phase pipe-to-soil potential (PSP) variations were obtained. The variations in PSP during the 17 March 2015 magnetic storm have led to the greatest corrosion rate of the analysed events. All the space weather events evaluated with high terminating impedance in this paper have contributed to increase the corrosion process. The applied technique can be used to evaluate the metal loss due to the high telluric activity associated with the geomagnetic storms at specific locations.
Simulating oceanic radiocarbon with the FAMOUS GCM: implications for its use as a proxy for ventilation and carbon uptake
Authors: Dentith Jennifer E. , Ivanovic Ruza F. , Gregoire Lauren J. , Tindall Julia C. , Robinson Laura F. , Valdes Paul J.
Published: October 2019

Abstract. Constraining ocean circulation and its temporal variability is crucial for understanding changes in surface climate and the carbon cycle. Radiocarbon (14C) is often used as a geochemical tracer of ocean circulation, but interpreting ∆14C in geological archives is complex. Isotope-enabled models enable us to directly compare simulated ∆14C values to Δ14C measurements and investigate plausible mechanisms for the observed signals. We have added three new tracers (water age, abiotic 14C, and biotic 14C) to the ocean component of the FAMOUS General Circulation Model to study large-scale ocean circulation and the marine carbon cycle. Following a 10 000 year spin-up, we prescribed the Suess effect (the isotopic imprint of anthropogenic fossil fuel burning) and the bomb pulse (the isotopic imprint of thermonuclear weapons testing) in a transient simulation spanning 1765 to 2000 CE. To validate the new isotope scheme, we compare the model output to direct ∆14C observations in the surface ocean (pre-bomb and post-bomb) and at depth (post-bomb only). We also compare the timing, shape and amplitude of the simulated marine bomb spike to ∆14C in geological archives from shallow-to-intermediate water depths across the North Atlantic. The model captures the large-scale structure and range of ∆14C values (both spatially and temporally) suggesting that, on the whole, the uptake and transport of 14C are well represented in FAMOUS. Differences between the simulated and observed values arise due to physical model biases (such as weak surface winds and over-deep North Atlantic Deep Water), demonstrating the potential of the 14C tracer as a sensitive, independent tuning diagnostic. We also examine the importance of the biological pump for deep ocean 14C concentrations and assess the extent to which 14C can be interpreted as a ventilation tracer. Comparing the simulated biotic and abiotic δ14C, we infer that biology has a spatially heterogeneous influence on 14C distributions in the surface ocean (between 18 and 30 ‰), but a near constant influence at depth (≈ 20 ‰). Nevertheless, the decoupling between the simulated water ages and the simulated 14C ages in FAMOUS demonstrates that interpreting proxy ∆14C measurements in terms of ventilation alone could lead to erroneous conclusions about palaeocean circulation. Specifically, our results suggest that ∆14C is only a faithful proxy for water age in regions with strong convection; elsewhere, the temperature dependence of the solubility of CO2 in seawater complicates the signal.