bluuebunny/crossref_metadata_2025 huggingface dataset:
A review of the total syntheses of triptolide
Authors: Zhang Xiang , Xiao Zaozao , Xu Hongtao
Published: August 2019

Triptolide is a complex triepoxide diterpene natural product that has attracted considerable interest in the organic chemistry and medicinal chemistry societies due to its intriguing structural features and multiple promising biological activities. In this review, progress in the total syntheses of triptolide are systematically summarized. We hope to gain a better understanding of the field and provide constructive suggestions for future studies of triptolide.
Untangling the Formation of Methoxymethanol (CH3OCH2OH) and Dimethyl Peroxide (CH3OOCH3) in Star-forming Regions
Authors: Zhu Cheng , Frigge Robert , Bergantini Alexandre , Fortenberry Ryan C. , Kaiser Ralf I.
Published: August 2019

Methoxymethanol (CH3OCH2OH) was recently detected toward the MM1 core in the high-mass star-forming region NGC 6334I. However, the underlying formation mechanisms of this complex organic molecule (COM) as well as its structural isomers ethylene glycol (HOCH2CH2OH) and the hitherto unobserved dimethyl peroxide (CH3OOCH3) are still elusive. Here, we report the very first confirmed synthesis of dimethyl peroxide—at various deuteration levels within interstellar analogous ices of D3-methanol (CD3OH) exposed to ionizing radiation at ultralow temperatures of 5 K. The discrimination of specific isomers is achieved by exploiting reflectron time-of-flight mass spectrometry coupled with isomer-selective photoionization of the subliming molecules in the temperature programmed desorption phase of the experiment. Based on the distribution of the identified species at distinct mass-to-charge ratios, we reveal primary and secondary reaction pathways to methoxymethanol, ethylene glycol, and dimethyl peroxide involving radical–radical recombination of methoxy (CH3O) and hydroxymethyl (CH2OH). Our findings help to constrain the formation mechanism of COMs detected within star-forming regions (methoxymethanol, ethylene glycol) and propose that the hitherto elusive dimethyl peroxide isomer represents an excellent candidate for future astronomical searches.
On the Gamma-Ray Nebula of Vela Pulsar. II. The Soft Spectrum of the Extended Radio Nebula
Authors: Bao Yiwei , Chen Yang
Published: August 2019

The Vela X pulsar wind nebula (PWN) is characterized by the extended radio nebula (ERN) and the central X-ray “cocoon.” We have interpreted the γ-ray spectral properties of the cocoon in the first paper; here, we account for the broadband photon spectrum of the ERN. Since the diffusive escape of the electrons from the TeV emitting region is expected to play an insignificant role in shaping the spectrum of the ERN, we attribute the GeV cutoff of the ERN to the reverse shock–PWN interaction. Due to the disruption of the reverse shock, most of the plasma of the PWN is driven into the ERN. During the subsequent reverberation phase, the ERN could be compressed by a large factor in radius, and the magnetic field in the ERN is thus significantly enhanced, burning off the high-energy electrons. We thus obtain the electron spectrum of the ERN, and the broadband spectrum of the ERN is explained satisfactorily.
BAT AGN Spectroscopic Survey. XVI. General Physical Characteristics of BAT Blazars
Authors: Paliya Vaidehi S. , Koss M. , Trakhtenbrot B. , Ricci C. , Oh K. , Ajello M. , Stern D. , Powell M. C. , Urry C. M. , Harrison F. , Lamperti I. , Mushotzky R. , Marcotulli L. , Mejía-Restrepo J. , Hartmann D.
Published: August 2019

The recently released 105-month Swift-Burst Alert Telescope (BAT) all-sky hard X-ray survey catalog presents an opportunity to study astrophysical objects detected in the deepest look at the entire hard X-ray (14–195 keV) sky. Here we report the results of a multifrequency study of 146 blazars from this catalog, quadrupling the number compared to past studies, by utilizing recent data from the Fermi-Large Area Telescope (LAT), Swift-BAT, and archival measurements. In our γ-ray analysis of ∼10 yr of the LAT data, 101 are found as γ-ray emitters, whereas, 45 remains LAT undetected. We model the broadband spectral energy distributions with a synchrotron-inverse Compton radiative model. On average, BAT detected sources host massive black holes (M
bh ∼ 109
M
⊙) and luminous accretion disks (L
d ∼ 1046 erg s−1). At high redshifts (z > 2), BAT blazars host more powerful jets with luminous accretion disks compared to those detected only with Fermi-LAT. We find good agreement in the black hole masses derived from the single-epoch optical spectroscopic measurements and standard accretion disk modeling approaches. Other physical properties of BAT blazars are similar to those known for Fermi-LAT detected objects.
A Partial Inventory of Observational Anisotropies in Single-dish Line-intensity Mapping
Authors: Chung Dongwoo T.
Published: August 2019

Line-intensity mapping, being an imperfect observation of the line-intensity field in a cosmological volume, will be subject to various anisotropies introduced in observation. Existing literature in the context of CO and [C ii] line-intensity mapping often predicts only the real-space, spherically averaged line-intensity power spectrum, with some works considering anisotropies while examining projection of interloper emission. We explicitly consider a simplified picture of redshift-space distortions and instrumental effects due to limited resolution, and how these distort an isotropic line-intensity signal in real space and introduce strong apparent anisotropies. The results suggest that while signal loss due to limited instrumental resolution is unavoidable, measuring the quadrupole power spectrum in addition to the monopole would still break parameter degeneracies present in monopole-only constraints, even without a measurement of the full anisotropic power spectrum.
Two Types of Confined Solar Flares
Authors: Li Ting , Liu Lijuan , Hou Yijun , Zhang Jun
Published: August 2019

With the aim of understanding the physical mechanisms of confined flares, we selected 18 confined flares during 2011–2017, and first classified them into two types based on their different dynamic properties and magnetic configurations. “Type I” confined flares are characterized by slipping reconnection, strong shear, and a stable filament. “Type II” flares have almost no slipping reconnection, and have a configuration in potential state after the flare. A filament erupts but is confined by a strong strapping field. “Type II” flares could be explained by 2D MHD models, while “type I” flares need 3D MHD models. Seven of 18 confined flares (∼39%) belong to “type I” and 11 (∼61%) are “type II.” The post-flare loops (PFLs) of “type I” flares have a stronger non-potentiality, but the PFLs in “type II” flares are weakly sheared. All the “type I” flares exhibit ribbon elongations parallel to the polarity inversion line (PIL) at speeds of several tens of km s−1. Only a small proportion of “type II” flares show ribbon elongations along the PIL. We suggest that different magnetic topologies and reconnection scenarios dictate the distinct properties for the two types of flares. Slipping magnetic reconnections between multiple magnetic systems result in “type I” flares. For “type II” flares, magnetic reconnections occur in antiparallel magnetic fields underlying the erupting filament. Our study shows that “type I” flares account for more than one third of all the large confined flares, and should not be neglected in further studies.
Vertical Tracer Mixing in Hot Jupiter Atmospheres
Authors: Komacek Thaddeus D. , Showman Adam P. , Parmentier Vivien
Published: August 2019

Aerosols appear to be ubiquitous in close-in gas giant atmospheres, and disequilibrium chemistry likely impacts the emergent spectra of these planets. Lofted aerosols and disequilibrium chemistry are caused by vigorous vertical transport in these heavily irradiated atmospheres. Here we numerically and analytically investigate how vertical transport should change over the parameter space of spin-synchronized gas giants. In order to understand how tracer transport depends on planetary parameters, we develop an analytic theory to predict vertical velocities and mixing rates (K
zz) and compare the results to our numerical experiments. We find that both our theory and numerical simulations predict that if the vertical mixing rate is described by an eddy diffusivity, then this eddy diffusivity K
zz should increase with increasing equilibrium temperature, decreasing frictional drag strength, and increasing chemical loss timescales. We find that the transition in our numerical simulations between circulation dominated by a superrotating jet and that with solely day-to-night flow causes a marked change in the vertical velocity structure and tracer distribution. The mixing ratio of passive tracers is greatest for intermediate drag strengths that correspond to this transition between a superrotating jet with columnar vertical velocity structure and day-to-night flow with upwelling on the dayside and downwelling on the nightside. Finally, we present analytic solutions for K
zz as a function of planetary effective temperature, chemical loss timescales, and other parameters, for use as input to 1D chemistry models of spin-synchronized gas giant atmospheres.
La notion d’événement d’écriture
Authors: Fraenkel Béatrice
Published: August 2019

Qu’entend-t-on par événement d’écriture ? L’analyse montre que, sous une apparente simplicité, l’expression mêle la notion d’événement – largement débattue par les historiens depuis Fernand Braudel (1985) – à celle de «  literacy event  » (Heath, 1983) forgée par des chercheurs proches des ethnologues de la communication. Or, les courants théoriques qui ont dominé cette double genèse, le structuralisme et le fonctionnalisme, ont soit rejeté l’événement en général hors du champ de leur recherche, soit l’ont ignoré au profit de l’étude d’activités d’écriture routinières vues comme des petits événements quotidiens. Si bien que les faits d’écriture qui nous intéressent, les actes singuliers, exceptionnels, héroïques, observés notamment dans l’espace public appellent à changer de paradigmes et à construire une notion d’événement d’écriture à la croisée d’une anthropologie pragmatique et d’une théorie des actes d’écriture.
Le street artivisme en Égypte : de l’écriture au cœur d’un événement à l’écriture-événement
Authors: Abdel Hamid Mohammad
Published: August 2019

Cet article traite de l’écriture street artiviste en Égypte, de ses apparitions en environnements urbain et socio-numérique, et de son implication dans l’événement révolutionnaire entre 2010 et 2013. L’analyse proposée suit le parcours de cette écriture subversive nouvelle en Égypte et son intégration hétéronome au cœur de la révolution pour s’arroger une autonomie et faire événement. Illustrant un événement, l’écriture urbaine et ses reprises en ligne s’octroient une part de légitimité et créent de nouvelles modalités d’action intégrant le répertoire collectif. Partant d’une approche sémiotique, inscrite dans une perspective pragmatiste, l’article tente de fournir des explications quant à l’événementialisation du street artivisme portée par un public politique qui y trouve un matériau symbolique pour configurer son récit mais aussi pour créer de nouveaux récits révolutionnaires.
Le Chanel Shopping Center au Grand Palais : de la haute-culture à la pop-couture
Authors: Kireche-Gerwig Rym
Published: August 2019

Le défilé prêt-à-porter Chanel automne/hiver 2014/15 expose des corps de mode dans le cadre d'un supermarché recréé sous un régime scénique particulier. D'une part, il hypertrophie les mécanismes de la publicité. D'autre part, il inscrit la collection dans une mémoire patrimonialisée. Cet article analyse la construction d'une scène d'énonciation où les mannequins jouent le rôle de consommatrices. La marque, jouant sur le brouillage des rôles entre invités et mannequins, produit une inversion carnavalesque entre culture et consommation et parodie les régimes de l'art et du commerce.
Ontologie(s) et matérialité(s) de la musique : de quoi l'œuvre est‑elle le nom ?
Authors: Després-Lonnet Marie , Micheau Béatrice
Published: August 2019

Le projet DOREMUS, sur lequel se basent les réflexions présentées dans cet article, ambitionne de modéliser, convertir et publier les données issues des catalogues musicaux de trois grandes institutions françaises, afin qu'elles puissent être partagées au‑delà des sphères professionnelles auxquelles elles étaient destinées jusqu'ici. La modélisation repose sur une ontologie documentaire qui associe au sein d'un réseau sémantique divers éléments et moments de nos pratiques musicales. Ce projet de formalisation nous a amenés à aborder des questions plus générales sur notre rapport documenté au monde, et plus précisément sur l'articulation entre les moments où les choses nous arrivent, ceux où nous nous en emparons conceptuellement, ceux où nous les envisageons matériellement en lien avec nos pratiques, et ceux enfin où, dans des dispositifs documentaires, nous les désignons, les décrivons et les mettons en réseau. En somme, comment mettons-nous nos pratiques et les choses qui les rendent ou qu'elles rendent possibles, en documents  ?
Using Systems Thinking to Implement the QSEN Informatics Competency
Authors: Phillips Janet M. , Stalter Ann M. , Goldschmidt Karen A. , Ruggiero Jeanne S. , Brodhead Josette , Bonnett Pamela L. , Provencio Robyn A. , Mckay Mary , Jowell Vicki , Merriam Deborah H. , Wiggs Carol M. , Scardaville Debra L.
Published: August 2019

There is an urgent need to improve the use and usability of the electronic health record (EHR) in health care to prevent undue patient harm. Professional development educators can use systems thinking and the QSEN competency, Informatics, to educate nurses about such things as nurse-sensitive indicators in preventing medical errors. This article presents teaching tips in using systems thinking to champion communication technologies that support error prevention (betterment).

[
J Contin Educ Nurs.
2019;50(9):392–397.]
Research Capacity and Research Training Needs of Clinical Nurses in Suzhou, China
Authors: Hu Huagang , Yu Xiang , Tang Zaixiang , Lin Lu
Published: August 2019

Background:

Several studies examined the research capacity of nurses in the United States and other countries. However, the research capacity of clinical nurses in China has not been systematically surveyed. Thus, there is a need to investigate and report the research capacity and training needs of nurses in China.

Method:

A cross-sectional survey was conducted using a structured questionnaire.

Results:

In 17 hospitals, 2,324 clinical nurses were surveyed. The results indicated that most of the nurses self-assessed that their research capacity was relatively low, as the average score was 65.47 ± 21.31 (total score = 30 to 150). Most of the nurses (
n
= 1,890, 83.1%) expressed the need for training in research. Linear regression analysis showed participation in nursing research practices and pursuing a higher degree could improve nurses' research capacity.

Conclusion:

Nurses' research capacity needs further improvement. More training courses on nursing research tailored to the requirements of nurses are needed.

[
J Contin Educ Nurs.
2019;50(9):423–432.]
Feasibility of Motivational Interviewing to Engage Older Inpatients in Fall Prevention: A Pilot Randomized Controlled Trial
Authors: Kiyoshi-Teo Hiroko , Northup-Snyder Kathlynn , Cohen Deborah J. , Dieckmann Nathan , Stoyles Sydnee , Eckstrom Elizabeth , Winters-Stone Kerri
Published: August 2019

In the current 3-month, two arm, unblinded, single site, pilot randomized controlled trial, 120 high fall risk hospitalized older adults (age ≥65) were contacted, and 67 participants were enrolled. The intervention arm received a brief motivational interviewing (MI) intervention. Both arms received routine hospital fall prevention protocols. Measurements were conducted at baseline, 2 days, 1 week, 1 month, and 3 months. MI intervention took approximately 21 minutes and was provided at beginning proficiency level. Approximately 66% of participants completed 3-month data collection. The intervention group reported a greater decrease in fear of falling after the intervention than the control arm (β = −0.856 vs. β = −0.236) and maintained fall prevention behaviors at 3 months (β = 0.001 vs. β = −0.083) (
p
< 0.05). The current study found brief MI for fall prevention in acute settings feasible and provided preliminary evidence for a positive impact of MI [
Journal of Gerontological Nursing, 45
(9), 19–29.].
Caring for People With Young Onset Dementia: An Interpretative Phenomenological Analysis of Family Caregivers' Experiences
Authors: Kilty Caroline , Boland Pauline , Goodwin John , de Róiste Áine
Published: August 2019

People with young onset dementia (YOD) experience many unique challenges. Similarly, family caregivers experience changing personal, familial, and societal roles. However, YOD is under recognized and under resourced with a lack of dedicated models of care. The current study explored family members' experience of caregiving for persons with YOD to identify barriers and opportunities to accessing support. Qualitative interviews were conducted with six family caregivers, using interpretative phenomenological analysis. Findings show that caregivers experience significant uncertainty within their role, difficulty accessing timely diagnosis, and face unclear care pathways and age-related restrictions to accessing support. These findings also reflect elements of ambiguous loss and anticipatory grief: caregivers experienced sudden changes to relationships and family structure, along with the anticipation of a changed future. Optimum models of care should target timely diagnosis and clear post-diagnosis pathways and services that are flexible, relevant, and accessible. Services should offer psychosocial support for family members as they adjust to their new role as caregivers. [
Journal of Psychosocial Nursing and Mental Health Services, 57
(11), 37–44.]
Complémentarités et concurrences sur le terrain du développement rural
Authors: Kaboré Koudbi
Published: August 2019

Cet article analyse l’évolution des relations entre les services techniques de l’agriculture et les acteurs de l’Union fraternelle des croyants (UFC) sur le terrain du développement rural à Dori au nord du Burkina Faso, depuis la création de l’UFC en 1973, au moment de la sécheresse. Alors que l’UFC s’était imposée comme un acteur central dans les années 1970 et 1980, et était perçue comme contribuant aux politiques de l’État, et que cette collaboration continue à être mise en avant par l’administration territoriale, la réforme du secteur agricole de 2001 a rebattu les cartes. En renforçant la volonté de contrôle étatique sur les organisations paysannes locales, et en faisant des services techniques des prestataires de projets, la réforme attise la rivalité entre ces deux acteurs du développement rural quant à la supervision des organisations paysannes et au contrôle des moyens financiers. Les agents des services techniques de l’agriculture contestent la bienveillance de l’administration publique envers l’UFC qui, selon eux, lui permet de développer des pratiques hors normes et de se soustraire à leur contrôle.
Revendications musulmanes sur la gouvernance de la laïcité au Burkina Faso
Authors: Ouédraogo Yacouba
Published: August 2019

Le présent article entend proposer une analyse des processus ayant conduit à la mise à l’agenda de la problématique de la gouvernance de la laïcité au Burkina Faso. Dans un contexte de réislamisation en Afrique subsaharienne, il essaie de donner un regard sur l’émergence de l’islam dans l’espace public dans ce pays où le christianisme joue un rôle important. Au Burkina Faso, les associations musulmanes francophones, non satisfaites de la gestion de la laïcité par l’État, engagent une lutte à partir du début des années 1990, non pas pour remettre en cause la laïcité constitutionnelle, mais pour réclamer plus d’équité dans le traitement des confessions religieuses. Elles demandent l’institution d’un observatoire de la laïcité. La question émerge dans l’espace politique à la faveur des réformes institutionnelles entreprises par l’État en 2011. Le forum national sur la laïcité, organisé en 2012, a été un moment fort de débats, qui traduit la légitimation du sujet et qui révèle les différentes conceptions de la laïcité qui traversent la société burkinabè. Les revendications musulmanes ont conduit à une coproduction d’action publique certes, mais elles ont aussi confirmé le développement d’un renouveau islamique et l’émergence d’une société civile musulmane au Burkina Faso.
Influencer, détourner, bloquer la « bonne gouvernance » au Burundi
Authors: Hirschy Justine
Published: August 2019

En 2011, l’adoption par le gouvernement burundais d’une stratégie nationale de bonne gouvernance et de lutte contre la corruption (2011-2015) apparaît comme un cas exemplaire de l’influence exercée par les bailleurs de fonds (organisations multilatérales et bilatérales) sur les politiques publiques des « pays sous régime d’aide ». Cependant, en se basant sur une analyse empirique approfondie de l’action publique dans un contexte multi-acteurs et extraverti, cet article présente une réalité beaucoup plus complexe.
Perspectives on a mobile application that maps assistive technology resources in Africa
Authors: Visagie Surona , Matter Rebecca , Kayange George , Chiwaula Mussa , Harniss Mark , Kahonde Callista
Published: August 2019

Background: Access to assistive technology (AT) is poor in African countries because of a lack of knowledge, resources, services and products. A mobile application, the AT-Info-Map, was developed to map AT availability in southern Africa.Objectives: This article aimed to describe users’ and suppliers’ perceptions of the AT-Info-Map app.Method: Qualitative data were collected in Zambia, Botswana, Malawi and Lesotho, through nine focus group discussions with 72 participants. Participants included AT users, AT suppliers and representatives of disability organisations. Data were thematically analysed.Results: Two broad themes, that is, usefulness of the AT-Info-Map application and technical issues and content, emerged from the data analysis. Subthemes under usefulness focused on the importance of using current technology, convenience of the app, the need for accuracy, responsiveness of supplier to user’s needs, influence on AT market and how the app creates an opportunity for networking. Challenges to download and navigate the app, the need for training in its use, exclusion of those not literate in English and those with visual impairments were subthemes under technical issues and content.Conclusion: The app was perceived as an important step to increase access to AT for persons with disabilities in less resourced settings. The challenges that emerged from the data analysis have led to the development of a web-based system that will complement or replace the app and improve AT information provision. However, the information provided by the app and website is still only a partial solution to improve AT access in Southern Africa.
Estratégias de Hedge para o Etanol Brasileiro: análise a partir de operações de contratos futuros doméstico e estrangeiros
Authors: Dario Capitani Daniel Henrique , Tonin Julyerme Matheus , Cruz Júnior José César
Published: August 2019

As mudanças ocorridas no mercado internacional de biocombustíveis provocaram significativas alterações no mercado de etanol brasileiro. Diante disso, este trabalho objetivou avaliar a eficiência do hedge e risco de base do etanol brasileiro utilizando contratos futuros no Brasil e EUA entre 2010 a 2019. Para isso, foi utilizado um modelo de hedge simultâneo de câmbio e preços. Os resultados indicam que a utilização de contratos estrangeiros não foi eficiente na maior parte dos anos, sobretudo em razão das variações cambiais, choques de oferta e intervenções nos mercados de combustíveis de ambos os países. Além disso, a operação com contratos americanos oferece maior variação no risco de base, sobretudo pelo fator cambial. No entanto, observa-se que nos períodos de menores volatilidades cambiais e de redução dos efeitos domésticos na regulação do mercado, a efetividade do hedge com contratos estrangeiros foi próxima daquela utilizando contratos nacionais, sugerindo-se uma alternativa na procura por contratos com maior liquidez.
Stroke and breast cancer in the United States during 2007–2017
Authors: Rethemiotaki Irene , Rethemiotakis Andrew
Published: August 2019

Introduction

The main purpose of this work is to study the malignant neoplasms of the breast and the incidence of strokes in the United States and to find not only statistically significant predictors for cancer, but also a possible association between breast cancer and stroke.

Material and methods

The statistical methods used to derive the results of this work are 2 and one-way analysis of variance (ANOVA) tests, in order to check the statistical significance of breast cancer in relation to socio-economic factors of patients. In addition, a multivariate logistic regression analysis was used with the odds ratio (OR) to find statistically significant prognostic factors for breast cancer. The Pearson correlation coefficient was used to find the relationship between breast cancer and stroke.

Results

According to multiple logistic regression analysis, widowed women have 11 times higher risk developing breast cancer, while white women who are unemployed but have worked previously have two times higher risk for the occurrence of this type of cancer. In addition, a statistically significant relationship was found between the number of cases of breast cancer and stroke.

Conclusions

Our results describe for the first time the importance of deprivation (of work and partner) as a primary prognostic risk factor for cancer. Moreover, we found a link between breast cancer diagnosis and stroke.
Variation in a tense/lax vowel pair in Dutch youngsters with different ethnic backgrounds
Authors: van Meel Linda , Hinskens Frans , van Hout Roeland
Published: August 2019

How do young bilingual speakers of current Turkish and Moroccan ethnolects of Dutch deal with phoneme contrasts that do not exist in their heritage languages and that are at the same time subject to regional and social variation in the Dutch speech community at large, such as that between Dutch phonemes /a:/ and /α/? Data from speakers from the Amsterdam and Nijmegen urban areas were analyzed and compared. Two variable properties of /a:/ and /α/ defining the phoneme pair were examined: (1) duration, and (2) place of articulation.

We found clear differences between the two urban areas (regional effect) and between the Amsterdam ethnic groups (social effect). In addition, we found variation dependent on the interlocutor (socio-stylistic effect) and the linguistic context. The main dimension of social and linguistic variation was place of articulation, length remaining the primary distinctive feature of the vowel pair. No heritage language effect was found. Young ethnolect speakers take part in existing patterns of regional and social variation.
Moral Conflicts of several “Green” terrestrial Negative Emission Technologies regarding the Human Right to Adequate Food – A Review
Authors: Hohlwegler Patrick
Published: August 2019

Abstract. Several terrestrial Negative Emission Technologies
(tNETs), like Bioenergy with Carbon Capture and Storage (BECCS),
Afforestation/Reforestation (AR) and Enhanced Weathering (EW), rely on
natural processes and could therefore be designated as “green” forms of
geoengineering. However, even those “green” tNETs may lead to undesirable
side effects and thereby provoke moral concerns and conflicts. In this
paper, I investigated whether BECCS, AR and EW would cause moral conflicts
regarding the human right to adequate food if implemented on a scale
sufficient to limit global warming “to well below 2 ∘C”.
Reviewing recent publications concerning BECCS, AR and EW, I found that EW
would not conflict with the human right to adequate food but would likely
even promote agricultural food production due to a higher nutrient
provision. However, EW does not provide a feasible solution to limit global
warming “to well below 2 ∘C”, since a large-scale deployment of
EW would require large investments and considerable amounts of energy to
grind suitable rock-material. In regard of BECCS and AR, I found that even
under the optimistic Representative Concentration Pathway 2.6 (RCP2.6), as
assessed by the Intergovernmental Panel on Climate Change (IPCC) in its
latest assessment report from 2013, a large-scale deployment of BECCS and/or
AR would cause moral conflicts regarding the human right to adequate food
for present and future generations. Due to this, I advocate for more and
stronger mitigation efforts in line with efficient land management actions
concerning, e.g. peats and soils, designated as “natural climate
solutions” (NCS) and a deployment of multiple tNETs in near future.
An IBBCEAS system for atmospheric measurements of glyoxal and methylglyoxal in the presence of high NO2 concentrations
Authors: Liu Jingwei , Li Xin , Yang Yiming , Wang Haichao , Wu Yusheng , Lu Xuewei , Chen Mindong , Hu Jianlin , Fan Xiaobo , Zeng Limin , Zhang Yuanhang
Published: August 2019

Abstract. A system based on incoherent broadband cavity-enhanced
absorption spectroscopy (IBBCEAS) has been developed for simultaneous
measurement of nitrogen dioxide (NO2), glyoxal (GLY), and methylglyoxal
(MGLY). In this system, the measured light absorption at around 460 nm is
spectrally resolved. The concentration of absorbers is determined from a
multicomponent fit. At an integration time of 100 s, the measurement
sensitivity (2σ) for NO2, GLY, and MGLY is 18, 30, and
100 ppt, respectively. The measurement uncertainty, which mainly originates
from path length calibration, sampling loss, and uncertainty of absorption
cross sections is estimated to be 8 % for NO2, 8 % for GLY, and
16 % for MGLY. When deploying the instrument during field observations, we
found significant influence of NO2 on the spectra fitting for
retrieving GLY and MGLY concentrations, which is caused by the fact that
NO2 has a higher absorption cross section and higher ambient
concentration. In order to minimize such an effect, a NO2 photolytic
convertor (NPC), which removes sampled NO2 at an efficiency of 76 %,
was integrated on the IBBCEAS system. Since sampled GLY and MGLY are mostly
(≥95 %) conserved after passing through the NPC, the quality of the
spectra fitting and the measurement accuracy of ambient GLY and MGLY under
NO2-rich environments could be improved.
Methods for identifying aged ship plumes and estimating contribution to aerosol exposure downwind of shipping lanes
Authors: Ausmeel Stina , Eriksson Axel , Ahlberg Erik , Kristensson Adam
Published: August 2019

Abstract. Ship traffic is a major source of aerosol particles, particularly near
shipping lanes and harbours. In order to estimate the contribution to
exposure downwind of a shipping lane, it is important to be able to measure
the ship emission contribution at various distances from the source. We
report on measurements of atmospheric particles 7–20 km downwind of a
shipping lane in the Baltic Sea Sulfur Emission Control Area (SECA) at a
coastal location in southern Sweden during a winter and a summer campaign.
Each ship plume was linked to individual ship passages using a novel method
based on wind field data and automatic ship identification system data
(AIS), where varying wind speeds and directions were applied to calculate a
plume trajectory. In a situation where AIS data are not matching measured
plumes well or if AIS data are missing, we provide an alternative method with
particle number concentration data. The shipping lane contribution to the
particle number concentration in Falsterbo was estimated by subtracting
background concentrations from the ship plume concentrations, and more than
150 plumes were analysed. We have also extrapolated the contribution to
seasonal averages and provide recommendations for future similar
measurements. Averaged over a season, the contribution to particle number
concentration was about 18 % during the winter and 10 % during the
summer, including those periods with wind directions when the shipping lane
was not affecting the station. The corresponding contribution to equivalent
black carbon was 1.4 %.
UK greenhouse gas measurements at two new tall towers for aiding emissions verification
Authors: Stavert Ann R. , O'Doherty Simon , Stanley Kieran , Young Dickon , Manning Alistair J. , Lunt Mark F. , Rennick Christopher , Arnold Tim
Published: August 2019

Abstract. Under the UK-focused Greenhouse gAs and Uk and Global
Emissions (GAUGE) project, two new tall tower greenhouse gas (GHG)
observation sites were established in the 2013/2014 Northern Hemispheric
winter. These sites, located at existing telecommunications towers, utilized
a combination of cavity ring-down spectroscopy (CRDS) and gas chromatography
(GC) to measure key GHGs (CO2, CH4, CO, N2O and SF6).
Measurements were made at multiple intake heights on each tower. CO2
and CH4 dry mole fractions were calculated from either CRDS
measurements of wet air, which were post-corrected with an instrument-specific empirical correction, or samples dried to between 0.05 %
H2O and 0.3 %
H2O using a Nafion® dryer, with a smaller correction
applied for the residual H2O. The impact of these two drying strategies
was examined. Drying with a Nafion® dryer was not found to
have a significant effect on the observed CH4 mole fraction; however,
Nafion® drying did cause a 0.02 µmol mol−1
CO2 bias. This bias was stable for sample CO2 mole fractions
between 373 and 514 µmol mol−1 and for sample H2O up to 3.5 %. As the calibration and standard gases are treated in the same manner,
the 0.02 µmol mol−1 CO2 bias is mostly calibrated out with
the residual error (≪0.01 µmol mol−1 CO2) well below
the World Meteorological Organization (WMO) reproducibility requirements.
Of more concern was the error associated with the empirical instrument-specific water correction algorithms. These corrections are relatively
stable and reproducible for samples with H2O between 0.2 % and 2.5 %,
CO2 between 345 and 449 µmol mol−1, and CH4 between
1743 and 2145 nmol mol−1. However, the residual errors in these
corrections increase to > 0.05 µmol mol−1 for
CO2 and > 1 nmol mol−1 for CH4 (greater than the
WMO internal reproducibility guidelines) at higher humidities and for
samples with very low (< 0.5 %) water content. These errors also
scale with the absolute magnitude of the CO2 and CH4 mole
fractions. As such, water corrections calculated in this manner are not
suitable for samples with low (< 0.5 %) or high (> 2.5 %) water contents and either alternative correction methods should be
used or partial drying or humidification considered prior to sample
analysis.
Towards understanding potential atmospheric contributions to abrupt climate changes: characterizing changes to the North Atlantic eddy-driven jet over the last deglaciation
Authors: Andres Heather J. , Tarasov Lev
Published: August 2019

Abstract. Abrupt climate shifts of large amplitudes were common features of the Earth's climate as it transitioned into and out of the last full glacial state approximately 20 000 years ago, but their causes are not yet established.
Midlatitude atmospheric dynamics may have played an important role in these climate variations through their effects on heat and precipitation distributions, sea ice extent, and wind-driven ocean circulation patterns.
This study characterizes deglacial winter wind changes over the North Atlantic (NAtl) in a suite of transient deglacial simulations using the PlaSim Earth system model (run at T42 resolution) and the TraCE-21ka (T31) simulation.
Though driven with yearly updates in surface elevation, we detect multiple instances of NAtl jet transitions in the PlaSim simulations that occur within 10 simulation years and a sensitivity of the jet to background climate conditions.
Thus, we suggest that changes to the NAtl jet may play an important role in abrupt glacial climate changes. We identify two types of simulated wind changes over the last deglaciation.
Firstly, the latitude of the NAtl eddy-driven jet shifts northward over the deglaciation in a sequence of distinct steps.
Secondly, the variability in the NAtl jet gradually shifts from a Last Glacial Maximum (LGM) state with a strongly preferred jet latitude and a restricted latitudinal range to one with no single preferred latitude and a range that is at least 11∘ broader.
These changes can significantly affect ocean circulation.
Changes to the position of the NAtl jet alter the location of the wind forcing driving oceanic surface gyres and the limits of sea ice extent, whereas a shift to a more variable jet reduces the effectiveness of the wind forcing at driving surface ocean transports. The processes controlling these two types of changes differ on the upstream and downstream ends of the NAtl eddy-driven jet.
On the upstream side over eastern North America, the elevated ice sheet margin acts as a barrier to the winds in both the PlaSim simulations and the TraCE-21ka experiment.
This constrains both the position and the latitudinal variability in the jet at LGM, so the jet shifts in sync with ice sheet margin changes.
In contrast, the downstream side over the eastern NAtl is more sensitive to the thermal state of the background climate.
Our results suggest that the presence of an elevated ice sheet margin in the south-eastern sector of the North American ice complex strongly constrains the deglacial position of the jet over eastern North America and the western North Atlantic as well as its variability.
Monthly gridded data product of northern wetland methane emissions based on upscaling eddy covariance observations
Authors: Peltola Olli , Vesala Timo , Gao Yao , Räty Olle , Alekseychik Pavel , Aurela Mika , Chojnicki Bogdan , Desai Ankur R. , Dolman Albertus J. , Euskirchen Eugenie S. , Friborg Thomas , Göckede Mathias , Helbig Manuel , Humphreys Elyn , Jackson Robert B. , Jocher Georg , Joos Fortunat , Klatt Janina , Knox Sara H. , Kowalska Natalia , Kutzbach Lars , Lienert Sebastian , Lohila Annalea , Mammarella Ivan , Nadeau Daniel F. , Nilsson Mats B. , Oechel Walter C. , Peichl Matthias , Pypker Thomas , Quinton William , Rinne Janne , Sachs Torsten , Samson Mateusz , Schmid Hans Peter , Sonnentag Oliver , Wille Christian , Zona Donatella , Aalto Tuula
Published: August 2019

Abstract. Natural wetlands constitute the largest and most uncertain source
of methane (CH4) to the atmosphere and a large fraction of them are found in the northern latitudes. These emissions are typically estimated using process (“bottom-up”) or inversion (“top-down”) models. However, estimates from these two types of models are not independent of each other since the top-down estimates usually rely on the a priori estimation of these emissions obtained with process models. Hence, independent spatially explicit validation data are needed. Here we utilize a random forest (RF) machine-learning technique to upscale CH4 eddy covariance flux measurements from 25 sites to estimate CH4 wetland emissions from the northern latitudes (north of 45∘ N). Eddy covariance data
from 2005 to 2016 are used for model development. The model is then used to predict emissions during 2013 and 2014. The predictive performance of the RF model is evaluated using a leave-one-site-out cross-validation scheme. The performance (Nash–Sutcliffe model efficiency =0.47) is comparable to previous studies upscaling net ecosystem exchange of carbon dioxide and studies comparing process model output against site-level CH4 emission data. The global distribution of wetlands is one major source of uncertainty for upscaling CH4. Thus, three wetland distribution maps are utilized in the upscaling. Depending on the wetland distribution map, the annual emissions for the northern wetlands yield 32 (22.3–41.2, 95 % confidence interval calculated from a RF model ensemble), 31 (21.4–39.9) or 38 (25.9–49.5) Tg(CH4) yr−1. To further evaluate the uncertainties of the upscaled CH4 flux data products we also compared them against output from two process models (LPX-Bern and WetCHARTs), and methodological issues related to CH4 flux upscaling are discussed. The monthly upscaled CH4 flux data products are available at
https://doi.org/10.5281/zenodo.2560163 (Peltola et al., 2019).
Global CRM/RM-scaled nutrient gridded dataset GND13
Authors: Aoyama Michio
Published: August 2019

Abstract. A global nutrients gridded dataset that might be the basis for studies of more accurate spatial distributions of nutrient in the global ocean was created and named GND13. During 30 cruises, reference materials of nutrients in seawater or their equivalents were used at all stations, and high-precision measurements were made. The precision of the nutrient analyses was better than 0.2 %, and comparability between stations was ensured. Data were collected from all of the hydrographic cruises from which nutrient data were available. Analyses were conducted at 243 crossover stations. Data from cruises with high quality control by using RM/CRM of nutrients were used as references to determine correction factors for adjusting nutrient concentrations obtained during other cruises. Dissolved oxygen concentrations obtained with similar protocols were added to the dataset. Finally, a dataset of nitrate, phosphate, silicate, and dissolved oxygen concentrations was created at latitude and longitude intervals of 0.5° and on 136 isobaric surfaces to depths of 6500 meters. This dataset has already been published at https://doi.org/10.17596/0000001 (Aoyama, 2017).
A low-cost device for measuring local magnetic anomalies in volcanic terrain
Authors: de Groot Bertwin M. , de Groot Lennart V.
Published: August 2019

Abstract. Reconstructions of the past behavior of the geomagnetic field critically depend on the magnetic signal stored in extrusive igneous rocks. These rocks record the Earth's magnetic field when they cool and retain this magnetization on geological timescales. In rugged volcanic terrain, however, the magnetic signal arising from the underlying flows may influence the ambient magnetic field as recorded by newly formed flows on top. To measure these local anomalies in the Earth's magnetic field directly we developed a low-cost field magnetometer based on a fluxgate sensor. To improve the accuracy of the obtained paleomagnetic vector and user-friendliness of the device, we combined this fluxgate sensor with tilt and GPS sensors to rotate the measured magnetic vector to true north, east, and down. The data acquisition is done using a ruggedized laptop, and data are immediately available for first-order interpretation. The first measurements done on Mt. Etna show local variations in the ambient magnetic field that are larger than expected and illustrate both the accuracy (certainly <0.5∘ in paleomagnetic direction) and potential of our new device.
A MACHINE LEARNING PIPELINE ARTICULATING SATELLITE IMAGERY AND OPENSTREETMAP FOR ROAD DETECTION
Authors: Zurbaran M. A. , Wightman P. , Brovelli M. A.
Published: August 2019

Abstract. Satellite imagery from earth observation missions enable processing big data to gather information about the world. Automatizing the creation of maps that reflect ground truth is a desirable outcome that would aid decision makers to take adequate actions in alignment with the United Nations Sustainable Development Goals. In order to harness the power that the availability of the new generation of satellites enable, it is necessary to implement techniques capable of handling annotations for the massive volume and variability of high spatial resolution imagery for further processing. However, the availability of public datasets for training machine learning models for image segmentation plays an important role for scalability.This work focuses on bridging remote sensing and computer vision by providing an open source based pipeline for generating machine learning training datasets for road detection in an area of interest. The proposed pipeline addresses road detection as a binary classification problem using road annotations existing in OpenStreetMap for creating masks. For this case study, Planet images of 3m resolution are used for creating a training dataset for road detection in Kenya.
A TENSOR BASED FRAMEWORK FOR LARGE SCALE SPATIO-TEMPORAL RASTER DATA PROCESSING
Authors: Bhattacharya S. , Braun C. , Leopold U.
Published: August 2019

Abstract. In this paper, we address the curse of dimensionality and scalability issues while managing vast volumes of multidimensional raster data in the renewable energy modeling process in an appropriate spatial and temporal context. Tensor representation provides a convenient way to capture inter-dependencies along multiple dimensions. In this direction, we propose a sophisticated way of handling large-scale multi-layered spatio-temporal data, adopted for raster-based geographic information systems (GIS). We chose Tensorflow, an open source software library developed by Google using data flow graphs, and the tensor data structure. We provide a comprehensive performance evaluation of the proposed model against r.sun in GRASS GIS. Benchmarking shows that the tensor-based approach outperforms by up to 60%, concerning overall execution time for high-resolution datasets and fine-grained time intervals for daily sums of solar irradiation [Wh.m-2.day-1].
Optimizing Wind Farm Control through Wake Steering using Surrogate Models based on High Fidelity Simulations
Authors: Hulsman Paul , Andersen Søren Juhl , Göçmen Tuhfe
Published: August 2019

Abstract. This paper aims to develop fast and reliable surrogate models for yaw-based wind farm control. The surrogates, based on polynomial chaos expansion (PCE), are built using high fidelity flow simulations combined with aeroelastic simulations of the turbine performance and loads. Developing a model for wind farm control is a challenging control problem due to the time-varying dynamics of the wake. Both the power output and the loading of the turbines are included in the optimization of wind farm control strategies. Optimization results performed using two Vestas V27 turbines in a row for a specific atmospheric condition suggest that a power gain of almost 3 % ± 1 % can be achieved at close spacing by yawing the upstream turbine more than 15°. At larger spacing, the power gain the optimization shows that yawing is not beneficial as the optimization reverts to normal operation. Furthermore, it was also identified that a reduction of the equivalent loads was obtained at the cost of power production. The total power gains are discussed in relation to the associated model errors and the uncertainty of the surrogate models used in the optimization, and the implication for wind farm control.