bluuebunny/crossref_metadata_2025 huggingface dataset:
Government Policy and the Disintegration of Village Community Life and Individual Identity in Urbanising Japan
Authors: Fawsitt John
Published: October 2019

In this chapter the author tries to assess the implications for society in Japan brought about by the continuing demographic shift from a rural to an urban society, resulting in changes to its communities' environment and social practices. While the decline in a population's economic effects are well-known, the social effects of the flight from the provincial villages, and what this means for society in its cultural, social, and environmental consequences, has been less explored. Particularly in the sphere of identity, the author contends that this phenomenon should be treated as a disintegration that brings unseen consequences rather than a shift, and that government policy is exacerbating the risks rather than alleviating them.
Landscapes and Local Identity
Authors: Janku Andrea
Published: October 2019

This chapter is the first part of an exploration into the history and meaning of landscapes, based on a case study of the “must-see” scenic spots or Eight Views (bajing 八景) of Linfen County in the south of China's Shanxi province. County histories not only include poems and travel accounts describing these places, but often also, from the 18th century onwards, images representing them. They are thus well-documented places, which makes it possible to trace fragments of their history and draw conclusions about the relationship between humans and their physical environment. This part of the study focuses on how the physical environment interlocked with the historical heritage of a place to form a cultural landscape that gave identity and meaning to a place and its people.
Landscapes and Environmental Change
Authors: Janku Andrea
Published: October 2019

This chapter is the second part of an exploration into the history and meaning of landscapes, based on a case study of the “must-see” scenic spots or Eight Views (bajing 八景) of Linfen County in the south of China's Shanxi province. While the first part focused on the value of these iconic landscapes as sources of identity, this chapter will show how their aesthetic appreciation is intrinsically linked to their productive power. The author argues that it was largely the idea of productivity that made these landscapes amenable for aesthetic consumption and viable as sources of identity and meaning. It was the inherent instability of these productive aspects that made their aesthetic appreciation even more significant, as it ultimately depended on the precarious balance between the two.
Automatic Circuit Design of CMOS Miller OTA Using Cuckoo Search Algorithm
Authors: Prajapati Pankaj P. , Shah Mihir V.
Published: October 2019

The circuit design of the CMOS based analog part of a mixed-signal integrated circuit (IC) needs a large fraction of the overall design cycle time. The automatic design of an analog circuit is inevitable, seeing recently development of System-on-Chip (SOC) design. This brings about the need to develop computer aided design (CAD) tools for automatic design of CMOS based analog circuits. In this article, a Cuckoo Search (CS) algorithm is presented for automatic design of a CMOS Miller Operational Transconductance Amplifier (OTA). The source code of the CS algorithm is developed using the C language. The Ngspice circuit simulator has been used as a fitness function creator and evaluator. A script file is written to provide an interface between the CS algorithm and the Ngspice simulator. BSIM3v3 MOSFET models with 0.18 µm and 0.35 µm CMOS technology have been used to simulate this circuit. The simulation results of this work are presented and compared with previous works reported in the literature. The experimental simulation results obtained by the CS algorithm satisfy all desired specifications for this circuit.
Drivers of Innovation Practices in SMEs
Authors: Modi Prateek , Rawani A. M.
Published: October 2019

In terms of industries or business, one of the very important aspects of any growing economy is SMEs which are responsible for driving innovation and development in different areas. SMEs should possess a strategy which manages decisions effectively. Innovation is the key to making such strategies effective to achieve the ultimate goals. Presently, there are so many studies available in the literature for big industries, but less literature is available which collects drivers of innovation practice in SMEs in one article. Hence this article concentrates on discovering some of the driving forces of innovation practice in SMEs through previous studies. There are some factors which act as drivers for innovation practice in SMEs, these drivers help the SMEs to achieve their desired target. A basic literature review approach is embraced to viably identify those key drivers. This study contributes to the innovation management articles on SMEs. Some future research constraints are also suggested in the article.
Users' Intention to Share Knowledge Using Wiki in Virtual Learning Community
Authors: Ismail Hany A.
Published: October 2019

Many educational organizations are using Wikis to enhance virtual learning to encourage knowledge sharing inside between students and instructors. Wiki is an ideal tool for the online knowledge sharing at educational organizations which help to achieve more collaborative work environment between students and instructors. However, educational organizations sometimes fail of building successful virtual community and users abound Wikis for several reasons. This research explored the use of Wikis to share knowledge in virtual learning community. A proposed conceptual framework was developed examining the UTAUT model in new context by using it to test the behavior intention to share knowledge through the Wiki technology in virtual community. A survey to postgraduate students shows that social influence, performance, and effort expectancy have impact on students' attitude to share knowledge through Wikis.
Jordan Learning Analytics Management Systems Innovation (Jordanian Universities)
Authors: Al Amoush Abdeleh Bassam , Sandhu Kamaljeet
Published: October 2019

Learning management systems (LMS's) are a necessary tool and well suited as earning tools and activities in higher education. However, each institute has a different LMS tool that allows to users (management, instructors and students) to use it for a daily activity. This article investigates the main factors for the acceptance of LMS at Jordanian universities. Is also presents a new LMS model for Jordanian context called Learning Management System Model (JLMS). This approach is used to identify important factors that could or do affect the acceptance of using an LMS at Jordanian universities.
Risk Assessment of Cosmetic Preservatives Using QSAR
Authors: Bhardwaj Monika , Masand Neeraj , Sahoo Jagannath , Patil Vaishali M.
Published: October 2019

Cosmetic manufacturers need to demonstrate the safety and efficacy of the products against microbial contamination to assure consumer safety and to improve shelf-life. The preservation strategies include chemical, physical, or physiological strategies. The most common is the use of antimicrobial agents. The toxicity assessment of preservatives used in cosmetic products is essential. It can be done by computational methods such as quantitative structure-activity relationship (QSAR) using several software such as ADME-Tox, TOPKAT, Dragon, T.E.S.T., and ECOSAR. The present manuscript elaborates a detailed view on cosmetic preservatives, regulatory aspects and application of computational strategies for toxicity prediction.
Adoption of Multi-screen Multitasking in Young Generation of China
Authors: Khan Shahid Kalim , Guoxin Li
Published: October 2019

Presently, people are increasingly becoming screen jugglers and frequently involving multitasking through multiple screens. The current study is focused on explaining multi-screen multitasking behavior of the younger generation in China. People like to self-regulate their routine behaviors to be productive and organized. Recent research in social psychology suggests that self-regulation occurs both deliberately and intuitively. This dual system approach of self-regulation promotes the idea that both reflective and impulsive forces are involved in determining human behavior. Owing to this conception, the present research opted for a dual system approach of self-regulation as the theoretical basis. Empirical data has been collected from university students in China and a total of 345 responses have been used for the analysis which has been performed through structural equation modeling in SmartPLS 3.0. The results indicate that the factors of both deliberative and automatic self-regulation are effective in determining multi-screen multitasking behavior.
Reply Speed as Nonverbal Cue in Text Messaging with a Read Receipt Display Function
Authors: Kato Shogo , Kato Yuuki , Ozawa Yasuyuki
Published: October 2019

In text messaging via mobile devices, many users face pressure to rapidly exchange messages. This study investigates reply speeds in smartphone messaging, focusing on messaging with a read receipt function, which notifies the sender of whether the recipient has read a sent message. Using a questionnaire targeting 213 female college students in Japan, we investigate the time until negative emotions (sadness, anxiety, anger and guilt) which occur while waiting for a reply. The authors also address factors of messaging dependency, and find that negative emotions arise in significantly less time when waiting for a reply to a read message than an unread one. Further, most negative emotions occur significantly earlier in high-dependency groups than in low-dependency groups when waiting for a reply in either status. These effects differed in part depending on the type of emotion and recipient. The authors discuss these findings in the context of reply speed as a nonverbal cue.
A Simple Criterion to Locate a Multinational Corporation Resulting from Optimization of Technological Knowledge Transfer
Authors: Leszczynska Dorota , Pruchnicki Erick
Published: October 2019

The aim of this study is to formulate both a conceptual and a mathematical model giving a criterion of choice for the location of an MNC in search of new technological knowledge and the means to optimize it. On the basis of a bibliographical study, we develop a conceptual argument in order to formulate hypotheses regarding the impact of distances and motivation on knowledge transfer and the acquisition's resulting performance. The assumptions thus formulated make it possible to justify the mathematical expression of performance in a function of the architectural distance, the knowledge transfer, and the motivation. The resolution of this optimization problem makes it possible to obtain the optimal architectural distance and the optimal motivation corresponding to the best choice of localization of an MNC. The authors deduce a simple criterion aiming at helping a manager confronted with the problem of localization choice. The presented model helps to define the typology of MNC units: isolating and exploiting a MNC's knowledge or using the local knowledge and transferring it to other units.
Impact of Technology-based Reflective Practice Tools on Student Skill Development
Authors: O'Reilly Sharleen , Milner Julia
Published: October 2019

The purpose of this study was to examine how students received the combination of technology-based tools implemented in a staged manner within a curriculum and if any specific tool was of greater benefit in developing their reflective practice skills. Participants were 45 tertiary students enrolled in a health professional course. Qualitative and quantitative analysis revealed student preference for individual tools changed over time. Students preferred supportive tools (simulated video recordings, group blogging and teaching approaches) earlier on and independent tools (e-journaling and online reflective summary writing) in their final year. The findings support the use of different reflective practice tools in course design to better support student development and improve student engagement in reflective practices.
Liquidação de operadoras de planos de assistência à saúde no Brasil
Authors: Bragança Ciro Gustavo , Pinheiro Laura Edith Taboada , Bressan Valéria Gama Fully , Soares Luiz Augusto de Carvalho Francisco
Published: October 2019

O mercado de saúde suplementar tem crescido sobretudo na última década. De acordo com a Agência Nacional de Saúde Suplementar (ANS), o sistema contava com 47,9 milhões de usuários em dezembro de 2016. Embora o crescimento de usuários, a quantidade de operadoras de planos de saúde (OPS) vem caindo desde a criação da ANS. Quando detectadas anormalidades graves de ordem operacional e econômico-financeiro das OPS, a ANS pode decretar regimes especiais, atuando de forma mais efetiva na recuperação das operadoras. O objetivo deste estudo foi analisar a influência da regulação e das intervenções da ANS na continuidade das OPS. Foi utilizada uma regressão logística de dados em painel com efeitos aleatórios, utilizando-se de 26 variáveis econômico-financeiras obtidas por meio de indicadores calculados a partir das informações contábeis das operadoras e variáveis dummies relacionadas às características das operadoras. Uma variável que medisse a influência da ANS na continuidade das OPS também foi utilizada, demonstrando-se significativa para previsão da insolvência. Pesquisas futuras podem abordar a técnica de regressão para dados de sobrevivência como Riscos Proporcionais de Cox e adotar critério de classificação das empresas insolventes com base em índice de margem de solvência das OPS.
Activation-Induced Cell Death of Mucosal-Associated Invariant T Cells Is Amplified by OX40 in Type 2 Diabetic Patients
Authors: Zhang Mei , Ming Siqi , Gong Sitang , Liang Siping , Luo Yuanmei , Liang Zibin , Cao Can , Lao Juanfeng , Shang Yuqi , Li Xingyu , Wang Manni , Zhong Guoquan , Xu Lingqing , Wu Minhao , Wu Yongjian
Published: October 2019

Mucosal-associated invariant T (MAIT) cells play a key role in local and systemic immune responses. Studies suggest that type 2 diabetes (T2D) is associated with alterations in the human MAIT cell response. However, the mechanisms that regulate the survival and homeostasis of human MAIT cells are poorly defined. In this study, we demonstrate that the costimulatory TNF superfamily receptor OX40 was highly expressed in MAIT cells of patients with T2D. Compared with OX40-negative MAIT cells, OX40-positive MAIT cells showed a high activation and a memory phenotype. Surprisingly, OX40 expression was negatively correlated with the frequency of MAIT cells in the peripheral blood of T2D patients. Increased cleaved caspase-3 levels were observed in OX40+-expressing MAIT cells in T2D patients. In vitro, activated OX40 signaling by recombinant OX40L protein promoted caspase-3 activation and apoptosis of MAIT cells. Inhibition of caspase-3 restored apoptosis of MAIT cells induced by OX40 signaling. These results identify OX40 as an amplifier of activation-induced cell death of human blood MAIT cells and shed new light on the regulation of MAIT cells in the phase of immune responses in T2D.
Role of sterile pyuria in association to elevated PSA values in the diagnosis of non-palpable prostate cancer?
Authors: Demir Selamettin
Published: October 2019

Objectives: Although cancer is believed to develop and progress with the involvement of inflammation, it is still unclear what the correlation between inflammation and prostate cancer is. This study based on results of transrectal ultrasound-guided prostate biopsies aimed to determine whether C-reactive protein (CRP) and sterile pyuria were clinically useful in the evaluation of patients with suspect of prostate cancer. Materials and methods: This study is a cross-sectional prospective study of patients without clinical prostatitis symptoms. Characteristics of the 200 consecutive patients recruited were 3-20 ng/mL value of serum prostate-specific antigen (PSA), normal digital rectal examination finding, and sterile urine culture result. All patients underwent 12-core prostatic biopsy. 163 of the 200 patients had benign prostatic hyperplasia confirmed through histology, while the residual 37 patients had prostate cancer. Patients with pre-treatment urinary leukocyte count ≤ 3/high power field were categorized as non-pyuria, whilst those with pre-treatment urinary leukocyte count > 3/high power field were categorized as pyuria. The serum CRP level was also used to differentiate patients before the biopsy. Subgroups were compared regarding a number of clinical variables. Results: Histology revealed that 70% of pyuria patients and 38.5% of non-pyuria patients presented inflammation (p = 0.001). The pyuria group exhibited significantly higher total PSA compared to the non-pyuria group (p = 0.044). The two groups did not differ significantly regarding cancer detection rate (p = 0.752). CRP groups were similar regarding cancer detection and histologically-detected inflammation rates. Conclusion: In patients with no evidence of clinical prostatitis, sterile pyuria should be considered as a cause of increased PSA. Although sterile pyuria cannot predict non-palpable prostate cancer, it should be taken into account in urological evaluation in order to demonstrate minute prostatic inflammation due to its simplicity, convenience and non-invasiveness.
Effects of antioxidant treatment on seminal parameters in patients undergoing in vitro fertilization
Authors: Gambera Laura , Stendardi Anita , Ghelardi Camilla , Fineschi Benedetta , Aini Rosamaria
Published: October 2019

Objective: The aim of this non controlled trial was to assess whether a therapy with an antioxidant supplement may improve spermatozoa quality in terms of number, motility, morphology and a higher number of successful conceptions in patients with oligoasthenoteratozoospermia undergoing cycles of medically assisted reproduction by intracytoplasmic sperm injection (ICSI). Materials and methods: 32 patients registered at A.G.I. Medica (Siena) medically assisted reproduction centre affected by fertility problems associated with oligoasthenoteratozoospermia were included in the study. Semen analysis were evaluated according to World Health Organization 2010, before and after treatment. Moreover, we used colorimetric tests to assess oxidative stress. After evaluating oocyte fertilisation rate and the quality of embryos obtained, data were statistically analysed. Result: Microscopy examination after the therapy, showed a general improvement in sperm parameters (number of sperms, progressive motility, viability and normal morphology) in both baseline and capacitated; also the levels of oxidative stress was notably lower after the treatment. Morever we evaluated the outcome of the IVF treatment, the percentage of fertilization and the number of embryos obtained, all the parameters was significantly higher in the N1 group. Conclusions: The outcomes of this trial seem to suggest that the administration of our food supplement improve semen parameters and that the evaluation of oxidative stress levels may become a diagnostic tool to assess male infertility in patients undergoing ART cycle.
Priapism induced by use of tamsulosin: A case report and review of the literature
Authors: Marconi Marcelo , Pavez Pablo , San Francisco Ignacio , Narvaez Paulette
Published: October 2019

Numerous medications have been associated to the development of priapism as an adverse reaction, the most common are intracavernosal vasoactive agents, antipsychotics and antidepressants. Alpha blockers, in particular tamsulosin which is widely used in different urological conditions, has been associated to priapism in only few case reports. We present the case of a healthy 45-year-old man who medicated himself with two doses of 0.4 mg of tamsulosin due to a renal colic with spontaneous passage of a 3 mm stone. Eight hours after the second tamsulosin dose the patient developed a persistent painful erection not associated to sexual stimulation that lasted for 6 hours. He was admitted to the emergency room, and after history taking and physical evaluation the diagnosis of ischemic priapism was made. The patient denied consumption of any other medication or drug during the last month, blood tests in particular hemogram were normal and no recent history of pelvic trauma was reported. To achieve detumescence, five boluses of 200 mcg of phenylephrine were injected directly in the corpora cavernosa, no further procedures were needed. In the follow-up the patient had no new priapism episodes and he reported no problems with erections in sexual intercourse. Tamsulosin is one of most indicated medications in urological general practice; though priapism has been rarely associated to its consumption the risk of this side effect exists, suggesting that patients should be counselled about it.
ec-Filters and ec-ideals in the functionally countable subalgebra of C*(X)
Authors: Veisi Amir
Published: October 2019

The purpose of this article is to study and investigate ec-filters on X and ec-ideals in C*c (X) in which they are in fact the counterparts of zc-filters on X and zc-ideals in Cc(X) respectively. We show that the maximal ideals of C*c (X) are in one-to-one correspondence with the ec-ultrafilters on X. In addition, the sets of ec-ultrafilters and zc-ultrafilters are in one-to-one correspondence. It is also shown that the sets of maximal ideals of Cc(X) and C*c (X) have the same cardinality. As another application of the new concepts, we characterized maximal ideals of C*c (X). Finally, we show that whether the space X is compact, a proper ideal I of Cc(X) is an ec-ideal if and only if it is a closed ideal in Cc(X) if and only if it is an intersection of maximal ideals of Cc(X).
Substantial ozone enhancement over the North China Plain from increased biogenic emissions due to heat waves and land cover in summer 2017
Authors: Ma Mingchen , Gao Yang , Wang Yuhang , Zhang Shaoqing , Leung L. Ruby , Liu Cheng , Wang Shuxiao , Zhao Bin , Chang Xing , Su Hang , Zhang Tianqi , Sheng Lifang , Yao Xiaohong , Gao Huiwang
Published: October 2019

Abstract. In the summer of 2017, heavy ozone pollution swamped most of the North China
Plain (NCP), with the maximum regional average of daily maximum 8 h ozone
concentration (MDA8) reaching almost 120 ppbv. In light of the continuing
reduction of anthropogenic emissions in China, the underlying mechanisms for
the occurrences of these regional extreme ozone episodes are elucidated from
two perspectives: meteorology and biogenic emissions. The significant
positive correlation between MDA8 ozone and temperature, which is amplified
during heat waves concomitant with stagnant air and no precipitation,
supports the crucial role of meteorology in driving high ozone
concentrations. We also find that biogenic emissions are enhanced due to
factors previously not considered. During the heavy ozone pollution episodes
in June 2017, biogenic emissions driven by high vapor pressure deficit
(VPD), land cover change and urban landscape yield an extra mean MDA8 ozone
of 3.08, 2.79 and 4.74 ppbv, respectively, over the NCP, which together
contribute as much to MDA8 ozone as biogenic emissions simulated using the
land cover of 2003 and ignoring VPD and urban landscape. In Beijing, the
biogenic emission increase due to urban landscape has a comparable effect on
MDA8 ozone to the combined effect of high VPD and land cover change between
2003 and 2016. In light of the large effect of urban landscape on biogenic
emission and the subsequent ozone formation, the types of trees may be
cautiously selected to take into account of the biogenic volatile organic compound (BVOC) emission during the afforestation of cities. This study highlights the vital contributions of
heat waves, land cover change and urbanization to the occurrence of extreme
ozone episodes, with significant implications for ozone pollution control in
a future when heat wave frequency and intensity are projected to increase
under global warming.
NH3 emissions from large point sources derived from CrIS and IASI satellite observations
Authors: Dammers Enrico , McLinden Chris A. , Griffin Debora , Shephard Mark W. , Van Der Graaf Shelley , Lutsch Erik , Schaap Martijn , Gainairu-Matz Yonatan , Fioletov Vitali , Van Damme Martin , Whitburn Simon , Clarisse Lieven , Cady-Pereira Karen , Clerbaux Cathy , Coheur Pierre Francois , Erisman Jan Willem
Published: October 2019

Abstract. Ammonia (NH3) is an essential reactive nitrogen species in the biosphere and through its use in agriculture in the form of fertilizer (important for sustaining humankind). The current emission levels, however, are up to 4 times higher than in the previous century and continue to grow with uncertain consequences to human health and the environment. While NH3 at its current levels is a hazard to environmental and human health, the atmospheric budget is still highly uncertain, which is a product of an overall lack of measurements. The capability to measure NH3 with satellites has opened up new ways to study the atmospheric NH3 budget. In this study, we present the first estimates of NH3 emissions, lifetimes and plume widths from large (>∼5 kt yr−1) agricultural and industrial point sources from Cross-track Infrared Sounder (CrIS) satellite observations across the globe with a consistent methodology. The same methodology is also applied to the Infrared Atmospheric Sounding Interferometer (IASI) (A and B) satellite observations, and we show that the satellites typically provide comparable results that are within the uncertainty of the estimates. The computed NH3 lifetime for large point sources is on average 2.35±1.16 h. For the 249 sources with emission levels detectable by the CrIS satellite, there are currently 55 locations missing (or underestimated by more than an order of magnitude) from the current Hemispheric Transport Atmospheric Pollution version 2 (HTAPv2) emission inventory and only 72 locations with emissions within a factor of 2 compared to the inventories. The CrIS emission estimates give a total of 5622 kt yr−1, for the sources analyzed in this study, which is around a factor of ∼2.5 higher than the emissions reported in HTAPv2. Furthermore, the study shows that it is possible to accurately detect short- and long-term changes in emissions, demonstrating the possibility of using satellite-observed NH3 to constrain emission inventories.
Relative humidity and O3 concentration as two prerequisites for sulfate formation
Authors: Fang Yanhua , Ye Chunxiang , Wang Junxia , Wu Yusheng , Hu Min , Lin Weili , Xu Fanfan , Zhu Tong
Published: October 2019

Abstract. Sulfate formation mechanisms have been discussed
extensively but are still disputed. In this work, a year-long particulate
matter (PM2.5) sampling campaign was conducted together with
measurements of gaseous pollutant concentrations and meteorological
parameters in Beijing, China, from March 2012 to February 2013. The sulfur
oxidation ratio (SOR), an indicator of secondary sulfate formation,
displayed a clear summer peak and winter valley, even though no obvious
seasonal variations in sulfate mass concentration were observed. A rapid
rise in the SOR was found at a relative humidity (RH) threshold of ∼45 % or an
O3 concentration threshold of ∼35 ppb, allowing us to
first introduce the idea that RH and O3 concentrations are two
prerequisites for rapid sulfate formation via multiphase reactions. In the
case of the RH threshold, this is consistent with current understanding of
the multiphase formation of sulfate, since it relates to the
semisolid-to-liquid phase transition of atmospheric aerosols. Correlation
analysis between SOR and aerosol water content (AWC) further backed this up. In the case of the
O3 concentration threshold, this is consistent with the consumption of
liquid oxidants in multiphase sulfate formation. The thresholds introduced
here lead us to a better understanding of the sulfate formation mechanisms and
sulfate formation variations. H2O2 might be the major oxidant of
sulfate formation, since another liquid-phase oxidant, O3, has
previously been shown to be unimportant. The seasonal variations in sulfate
formation could be accounted for by variations in the RH and O3
prerequisites. For example, over the year-long study, the fastest
SO2-to-sulfate conversion occurred in summer, which was associated with
the highest values of O3 (and also H2O2) concentration and
RH. The SOR also displayed variations with pollution levels; i.e. the SOR
increased with PM2.5 in all seasons. Such variations were primarily
associated with a transition from the slow gas-phase formation of sulfate to
rapid multiphase reactions, since RH increased higher than its prerequisite
value of around 45 % as pollution evolved. In addition, the self-catalytic
nature of sulfate formation (i.e. the formation of hydrophilic sulfate
aerosols under high RH conditions results in an increase in aerosol water
content, which results in greater particle volume for further multiphase
sulfate formation) also contributed to variations among the pollution
scenarios.
Improved FTIR retrieval strategy for HCFC-22 (CHClF2), comparisons with in situ and satellite datasets with the support of models, and determination of its long-term trend above Jungfraujoch
Authors: Prignon Maxime , Chabrillat Simon , Minganti Daniele , O'Doherty Simon , Servais Christian , Stiller Gabriele , Toon Geoffrey C. , Vollmer Martin K. , Mahieu Emmanuel
Published: October 2019

Abstract. Hydrochlorofluorocarbons (HCFCs) are the first, but
temporary, substitution products for the strong ozone-depleting
chlorofluorocarbons (CFCs). HCFC consumption and production are currently
regulated under the Montreal Protocol on Substances that Deplete the Ozone
Layer and their emissions have started to stabilize or even decrease. As
HCFC-22 (CHClF2) is by far the most abundant HCFC in today's
atmosphere, it is crucial to continue to monitor the evolution of its
atmospheric concentration. In this study, we describe an improved HCFC-22
retrieval strategy from ground-based high-resolution Fourier transform
infrared (FTIR) solar spectra recorded at the high-altitude scientific
station of Jungfraujoch, the Swiss Alps, 3580 m a.m.s.l. (above mean sea level). This new
strategy distinguishes tropospheric and lower-stratospheric partial columns.
Comparisons with independent datasets, such as the Advanced Global Atmospheric Gases
Experiment (AGAGE) and the Michelson Interferometer for Passive Atmospheric
Sounding (MIPAS), supported by models, such as the Belgian Assimilation System for
Chemical ObErvation (BASCOE) and the Whole Atmosphere Community Climate
Model (WACCM), demonstrate the validity of our tropospheric and lower-stratospheric long-term time series. A trend analysis on the datasets used
here, now spanning 30 years, confirms the last decade's decline in
the HCFC-22 growth rate. This updated retrieval strategy can be adapted for
other ozone-depleting substances (ODSs), such as CFC-12. Measuring or
retrieving ODS atmospheric concentrations is essential for scrutinizing the
fulfilment of the globally ratified Montreal Protocol.
Improving the prediction of an atmospheric chemistry transport model using gradient boosted regression trees
Authors: Ivatt Peter D. , Evans Mathew J.
Published: October 2019

Abstract. Predictions from process-based models of environmental systems are biased, due to uncertainties in their inputs and parameterisations, reducing their utility. We develop a predictor for the bias in tropospheric ozone (a key pollutant) calculated by an atmospheric chemistry transport model (GEOS-Chem), based on outputs from the model and observations of ozone from both the surface (EPA, EMEP and GAW) and the ozone-sonde networks. We train a gradient-boosted decision tree algorithm (XGBoost) to predict model bias, with model and observational data for 2010–2015, and then test the approach using the years 2016–2017. We show that the bias-corrected model performs significantly better than the uncorrected model. The root mean square error is reduced from from 16.21 ppb to 7.48 ppb, the normalised mean bias is reduced from 0.28 to −0.04, and the Pearson's R is increased from 0.479 to 0.841. Comparisons with observations from the NASA ATom flights (which were not included in the training) also show improvements but to a smaller extent reducing the RMSE from 12.11 ppb to 10.50 ppb, the NMB from 0.08 to 0.06 and increasing the Pearson's R from 0.761 to 0.792. We attribute the smaller improvements to the lack of routine observational constraints of the remote troposphere. We explore the choice of predictor (bias prediction versus direct prediction) and conclude both may have utility. We show that the method is robust to variations in the volume of training data, with approximately a year of data needed to produce useful performance. Data denial experiments (removing observational sites from the algorithm training) shows that information from one location (for example Europe) can reduce the model bias over other locations (for example North America) which might provide insights into the processes controlling the model bias. We conclude that combining machine learning approaches with process based models may provide a useful tool for improving performance of air quality forecasts or to provide enhanced assessments of the impact of pollutants on human and ecosystem health, and may have utility in other environmental applications.
The isotopic composition of atmospheric nitrous oxide
observed at the high-altitude research station Jungfraujoch,
Switzerland
Authors: Yu Longfei , Harris Eliza , Henne Stephan , Eggleston Sarah , Steinbacher Martin , Emmenegger Lukas , Zellweger Christoph , Mohn Joachim
Published: October 2019

Abstract. Atmospheric nitrous oxide (N2O) levels have been continuously growing since preindustrial times. Mitigation requires information about sources and sinks on the regional and global scales. Isotopic composition of N2O in the atmosphere could contribute valuable constraints. However, isotopic records of N2O in the unpolluted atmosphere remain too scarce for large-scale N2O models. Here, we report the results of discrete air samples collected weekly to bi-weekly over a five-year period at the high-altitude research station Jungfraujoch, located in central Switzerland. High-precision N2O isotopic measurements were made using a recently developed preconcentration-laser spectroscopy technique. The measurements of discrete samples were accompanied by in situ continuous measurements of N2O mixing ratios. Our results indicate a pronounced seasonal pattern with minimum N2O mixing ratios in late summer, associated with a maximum in δ15Nbulk and a minimum in intramolecular 15N site preference (δ15NSP). This pattern is most likely due to stratosphere-troposphere exchange (STE), which delivers N2O-depleted but 15N-enriched air from the stratosphere into the troposphere. Variability in δ15NSP induced by changes in STE may be masked by biogeochemical N2O production processes in late summer, which are possibly dominated by a low-δ15NSP pathway of N2O production (denitrification), providing an explanation for the observed seasonality of δ15NSP. Footprint analyses and atmospheric transport simulations of N2O for Jungfraujoch suggest that regional emissions from the planetary boundary layer contribute to seasonal variations of atmospheric N2O isotopic composition at Jungfraujoch, albeit more clearly for δ15NSP and δ18O than for δ15Nbulk. With the time-series of five years, we obtained a significant interannual trend for δ15Nbulk after deseasonalization (−0.052±0.012 ‰ a−1), indicating that the atmospheric N2O increase is due to isotopically depleted N2O sources. We estimated the average isotopic signature of anthropogenic N2O sources with a two-box model to be −8.6±0.6 ‰ for δ15Nbulk, 34.8±3 ‰ for δ18O and 10.7±4 ‰ for δ15NSP. Our study demonstrates that seasonal variation of N2O isotopic composition in the background atmosphere is important when determining interannual trends. More frequent, high-precision and inter-laboratory compatible measurements of atmospheric N2O isotopocules, especially for δ15NSP, are needed to better constrain anthropogenic N2O sources, and thus the contribution of biogeochemical processes to N2O growth on the global scale.
Cloud history changes water–ice–surface interactions of oxide mineral aerosols (e.g. Silica)
Authors: Abdelmonem Ahmed , Ratnayake Sanduni , Toner Jonathan D. , Lützenkirchen Johannes
Published: October 2019

Abstract. Mineral aerosol particles can act as ice nucleators, and many insights have been obtained on water freezing as a function of mineral surface properties such as the charge or morphology. Previous studies have mainly focused on pristine samples, despite the fact that under natural atmospheric conditions, aerosol particles age. For example, an aerosol-containing cloud droplet can go through different freeze-melt cycles, so that not only the aerosol surface structure may change, but also the ionic strength and pH of the cloud droplet. The potential variation of the surface properties of an ice nucleating particle during its residence in the atmosphere has been largely overlooked. Here, we use an environmental cell in conjunction with nonlinear spectroscopy (second-harmonic generation) to study the effect of freeze-melt processes on aqueous chemistry at silica surface at low pH. We found that the successive freeze-melt cycles disrupt the dissolution equilibrium, substantially changing the surface properties, giving rise to marked variations in the interfacial water structure and the ice nucleation ability of the surface. The degree-of-order of water molecules, next to the surface at a specific temperature, decreases and then increases again with sample aging. The water ordering–cooling dependence and ice nucleation ability improve continuously.
Quantifying CH4 emissions from hard coal mines using mobile sun-viewing Fourier transform spectrometry
Authors: Luther Andreas , Kleinschek Ralph , Scheidweiler Leon , Defratyka Sara , Stanisavljevic Mila , Forstmaier Andreas , Dandocsi Alexandru , Wolff Sebastian , Dubravica Darko , Wildmann Norman , Kostinek Julian , Jöckel Patrick , Nickl Anna-Leah , Klausner Theresa , Hase Frank , Frey Matthias , Chen Jia , Dietrich Florian , Nȩcki Jarosław , Swolkień Justyna , Fix Andreas , Roiger Anke , Butz André
Published: October 2019

Abstract. Methane (CH4) emissions from coal production amount to roughly one-third of European anthropogenic CH4 emissions in the atmosphere. Poland is the largest hard coal producer in the European Union with the Polish side of the Upper Silesian Coal Basin (USCB) as the main part of it. Emission estimates for CH4 from the USCB for individual coal mine ventilation shafts range between 0.03 and 20 kt a−1, amounting to a basin total of roughly 440 kt a−1 according to the European Pollutant Release and Transfer Register (E-PRTR, http://prtr.ec.europa.eu/, 2014). We mounted a ground-based, portable, sun-viewing FTS (Fourier transform spectrometer) on a truck for sampling coal mine ventilation plumes by driving cross-sectional stop-and-go patterns at 1 to 3 km from the exhaust shafts. Several of these transects allowed for estimation of CH4 emissions based on the observed enhancements of the column-averaged dry-air mole fractions of methane (XCH4) using a mass balance approach. Our resulting emission estimates range from 6±1 kt a−1 for a single shaft up to 109±33 kt a−1 for a subregion of the USCB, which is in broad agreement with the E-PRTR reports. Three wind lidars were deployed in the larger USCB region providing ancillary information about spatial and temporal variability of wind and turbulence in the atmospheric boundary layer. Sensitivity studies show that, despite drawing from the three wind lidars, the uncertainty of the local wind dominates the uncertainty of the emission estimates, by far exceeding errors related to the XCH4 measurements themselves. Wind-related relative errors on the emission estimates typically amount to 20 %.
Introducing the 4.4 km Spatial Resolution MISR Aerosol Product
Authors: Garay Michael J. , Witek Marcin L. , Kahn Ralph A. , Seidel Felix C. , Limbacher James A. , Bull Michael A. , Diner David J. , Hansen Earl G. , Kalashnikova Olga V. , Lee Huikyo , Nastan Abigail M. , Yu Yan
Published: October 2019

Abstract. The Multi-angle Imaging SpectroRadiometer (MISR) instrument has been operational on the National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) Terra satellite since early 2000, creating an extensive data set of global Earth observations. Here we introduce the latest version of the MISR aerosol products. The Level 2 (swath) product, which is reported on a 4.4 km spatial grid, is designated Version 23 (V23) and contains retrieved aerosol optical depth (AOD) and aerosol particle property information derived from MISR's multi-angle observations over both land and water. The changes from the previous version of the algorithm (V22) have significant impacts on the data product and its interpretation. The V23 data set is created from two separate retrieval algorithms that are applied over dark water and land surfaces, respectively. Besides increasing the horizontal resolution to 4.4 km compared with the coarser 17.6 m resolution in V22, and streamlining the format and content, the V23 product has added geolocation information, pixel-level uncertainty estimates, and improved cloud screening. MISR data can be obtained from the NASA Langley Research Center Atmospheric Science Data Center at https://eosweb.larc.nasa.gov/project/misr/misr_table. The version number for the V23 Level 2 aerosol product is F13_0023. The Level 3 (gridded) aerosol product is still reported at 0.5° x 0.5° spatial resolution with results aggregated from the higher-resolution Level 2 data. The format and content at Level 3 have also been updated to reflect the changes made at Level 2. The Level 3 product associated with the V23 Level 2 product version is designated F15_0032. Both the Level 2 and Level 3 products are now provided in NetCDF format.
Using global reanalysis data to quantify and correct airflow distortion bias in shipborne wind speed measurements
Authors: Landwehr Sebastian , Thurnherr Iris , Cassar Nicolas , Gysel-Beer Martin , Schmale Julia
Published: October 2019

Abstract. At sea, wind forcing is responsible for the formation and development of surface waves and represents an important source of near surface turbulence. Therefore, processes related to near surface turbulence and wave breaking, such as sea spray emission and air-sea gas exchange are often parametrised with wind speed. Shipborne wind speed measurements thus provide highly relevant observations. They can, however, be compromised by flow distortion due to the ship's structure and objects nearby the anemometer that modify the airflow, leading to a deflection of the apparent wind direction and positive or negative acceleration of the apparent wind speed. The resulting errors in the estimated true wind speed can be greatly magnified at low wind speeds. For some research ships, correction factors have been derived from computational fluid dynamic models or through direct comparison with wind speed measurements from buoys. These correction factors can, however, loose their validity due to changes of the structures nearby the anemometer and thus require frequent re-evaluation, which is costly in either computational power or ship time. Here we evaluate if global weather forecast model data can be used to quantify the flow distortion bias in shipborne wind speed measurements. The method is tested on data from the Antarctic Circumnavigation Expedition (ACE) on board the R/V Akademik Tryoshnikov, which are compared with ERA-5 reanalysis wind speeds. We find that, depending on the relative wind direction, the relative wind speed and direction measurements are biased by −37 % to +20 % and −13° to +15°, respectively. The resulting error in the true wind speed is +11 % on average but ranges from −5 % to +40 % (5th and 95th percentile). After applying the bias correction, the uncertainty in the true wind speed is reduced to 5 % and depends mainly on the average accuracy of the ERA-5 data over the period of the experiment. The obvious drawback of this approach is the potential intrusion of model bias in the correction factors. We show that this problem can be somewhat mediated when the error propagation in the true wind correction is accounted for and used to weight the observations. We discuss the potential caveats and limitations of this approach and conclude that it can be used to quantify flow distortion bias for ships that operate on a global scale. The method can also be valuable to verify Computational Fluid Dynamic studies of airflow distortion on research vessels.
Migrating and Non-Migrating Tides Observed in the Stratosphere from FORMOSAT-3/COSMIC Temperature Retrievals
Authors: Das Uma , Ward William , Pan Chen Jeih , Das Sanat Kumar
Published: October 2019

Abstract. FORMOSAT-3/COSMIC temperature data during 2009 to 2010 are analysed for tides in the middle atmosphere from ~ 10 to 50 km. COSMIC is a set of six micro satellites in near sun synchronous orbits with 30° orbital separations and provides good phase space sampling of tides. Short term tidal variability is deduced by considering ± 10 days' data together. The DW1 tide is found to peak over the equator at 30 km. It maximises and slightly shifts poleward during winters and thus is attributed to ozone absorption. Over mid and high latitudes, DW1 and the non-migrating tides DS0 and DW2 are intermittent in nature. Numerical experiments in the current study show that these could be a result of aliasing as they are found to occur at times of steep rise or fall in the mean temperature, particularly during the SSW of 2010. Further, stationary planetary wave components are found to be of very large amplitudes in the northern hemispheres reaching 18 K at 30 km over 65° N. By using data from COSMIC over shorter durations, aliasing between SPW and non-migrating tides is reduced and thus results in the large amplitudes of the former. This study clearly indicates that non-linear interactions are not a very important source of generation of the non migrating tides in the high latitude winter hemisphere. There is also a modulation of SPW1 by ~ 60 days in the high latitudes, which was not seen earlier.