bluuebunny/crossref_metadata_2025 huggingface dataset:
The Physical System of the Arctic Ocean and Subarctic Seas in a Changing Climate
Authors: Campos Camila , Horn Myriel
Published: August 2018

The Earth’s climate is changing and the poles are particularly sensitive to the global warming, with most evident implications over the Arctic. While summer sea ice reduced significantly compared to the previous decades, and the atmospheric warming is amplified over the Arctic, changes in the ocean are less obvious due to its higher inertia. Still, impacts of the changing climate on high-latitude and polar oceans are already observable and expected to further increase. The northern seas are essential regions for the maintenance of the Atlantic Meridional Overturning Circulation, which in turn is a key aspect of the maritime climate. Alterations in heat and freshwater/salinity content in the Arctic Ocean and adjacent seas impact and are closely linked to buoyancy flux distributions, which control the vertical and horizontal motion of water masses, thus impacting the climate system on a longer time scale. In this context, we set our focus on the Arctic Ocean and Atlantic subarctic seas, review some of the contemporary knowledge and speculations on the complex coupling between atmosphere, sea ice, and ocean, and describe the important elements of its physical oceanography. This assessment is an attempt to raise awareness that investigating the pathways and timescales of oceanic responses and contributions is fundamental to better understand the current climate change.
Phytoplankton Responses to Marine Climate Change – An Introduction
Authors: Käse Laura , Geuer Jana K.
Published: August 2018

Phytoplankton are one of the key players in the ocean and contribute approximately 50% to global primary production. They serve as the basis for marine food webs, drive chemical composition of the global atmosphere and thereby climate. Seasonal environmental changes and nutrient availability naturally influence phytoplankton species composition. Since the industrial era, anthropogenic climatic influences have increased noticeably – also within the ocean. Our changing climate, however, affects the composition of phytoplankton species composition on a long-term basis and requires the organisms to adapt to this changing environment, influencing micronutrient bioavailability and other biogeochemical parameters. At the same time, phytoplankton themselves can influence the climate with their responses to environmental changes. Due to its key role, phytoplankton has been of interest in marine sciences for quite some time and there are several methodical approaches implemented in oceanographic sciences. There are ongoing attempts to improve predictions and to close gaps in the understanding of this sensitive ecological system and its responses.
Reading the Book of Life – Omics as a Universal Tool Across Disciplines
Authors: Brüwer Jan David , Buck-Wiese Hagen
Published: August 2018

In the last centuries, new high-throughput technologies, including sequencing and mass-spectrometry, have emerged and are constantly refurbished in order to decipher the molecular code of life. In this review, we summarize the physiological background from genes via transcriptome to proteins and metabolites and discuss the variety of dimensions in which a biological entity may be studied. Herein, we emphasize regulatory processes which underlie the plasticity of molecular profiles on different ome layers. We discuss the four major fields of omic research, namely genomics, transcriptomics, proteomics, and metabolomics, by providing specific examples and case studies for (i) the assessment of functionality on molecular, organism, and community level; (ii) the possibility to use omic research for categorization and systematic efforts; and (iii) the evaluation of responses to environmental cues with a special focus on anthropogenic influences. Thereby, we exemplify the knowledge gains attributable to the integration of information from different omes and the enhanced precision in predicting the phenotype. Lastly, we highlight the advantages of combining multiple omics layers in assessing the complexity of natural systems as meta-communities and -organisms.
Spectrum of movement disorders and neurotransmitter abnormalities in paediatric POLG disease
Authors: Papandreou A. , Rahman S. , Fratter C. , Ng J. , Meyer E. , Carr L. J. , Champion M. , Clarke A. , Gissen P. , Hemingway C. , Hussain N. , Jayawant S. , King M. D. , Lynch B. J. , Mewasingh L. , Patel J. , Prabhakar P. , Neergheen V. , Pope S. , Heales S. J. R. , Poulton J. , Kurian Manju A.
Published: August 2018

Objectives

To describe the spectrum of movement disorders and cerebrospinal fluid (CSF) neurotransmitter profiles in paediatric patients with POLG disease.

Methods

We identified children with genetically confirmed POLG disease, in whom CSF neurotransmitter analysis had been undertaken. Clinical data were collected retrospectively. CSF neurotransmitter levels were compared to both standardised age‐related reference ranges and to non‐POLG patients presenting with status epilepticus.

Results

Forty‐one patients with POLG disease were identified. Almost 50% of the patients had documented evidence of a movement disorder, including non‐epileptic myoclonus, choreoathetosis and ataxia. CSF neurotransmitter analysis was undertaken in 15 cases and abnormalities were seen in the majority (87%) of cases tested. In many patients, distinctive patterns were evident, including raised neopterin, homovanillic acid and 5‐hydroxyindoleacetic acid levels.

Conclusions

Children with POLG mutations can manifest with a wide spectrum of abnormal movements, which are often prominent features of the clinical syndrome. Underlying pathophysiology is probably multifactorial, and aberrant monoamine metabolism is likely to play a role.
How Online Reviews Become Helpful: A Dynamic Perspective
Authors: Lu Shuya , Wu Jianan , Tseng Shih-Lun (Allen)
Published: August 2018

Online product reviews aid consumer decision making. Although many studies show that review characteristics have salient effects on review helpfulness, little research has investigated whether such effects change temporally. To bridge this research gap, we study the dynamic formation of review helpfulness by considering the behaviors of three major players in a typical review system: consumers, the review hosting firm, and reviewers. This study uses both dynamic and static drivers of review helpfulness to examine temporal changes in their effects on review helpfulness, along two time characteristics of a post: its lifespan and its timing. Daily data collected from Amazon show that for long post lifespans or late post timing, the effects of static drivers and the spillover effect of dynamic drivers weaken, but the carryover effect of dynamic drivers strengthens. For vendors to leverage user reviews of a product, high-quality reviews posted early are extremely important and should be cultivated diligently. Sorting by review quality attributes, such as review length, also can effectively prolong the time window for reviewers to write high-quality detailed reviews.
Touchable Apps: Exploring the Usage of Touch Features and Their Impact on Engagement
Authors: Shi Savannah Wei , Kalyanam Kirthi
Published: August 2018

Touch has become an inseparable element of mobile platforms. This study examines the use of different touch features and the impact of these touch gestures on consumer engagement with a mobile shopping app. We focus on three informational touch features that are common among shopping apps: touch to zoom in on a page (zoom-page), to view product details (product-view), and to be directed to outside links (open-webpage). We develop a two-level model that captures (1) consumers’ decisions to stay with or leave an app and (2) their use of touch features. Our main results empirically demonstrate the strong explanatory power of informational touch gestures, especially their dwell time, in consumer app browsing decisions, whereas navigational touch gestures do not significantly affect app stay likelihood. A longer dwell time and early use of zoom-page within a session encourage the stay. Moreover, we observe strong synergy and antergy (negative synergy) among these touch gestures. The cumulative dwell time and temporal progression of touch gestures affect subsequent touch feature usage. Managerially, our results suggest that an early intervention that encourages the use of zoom-page increases app stay likelihood, and marketers may apply our model to quantify the impact of such interventions on consumer browsing decisions at the individual level. The results also shed light on how marketers can infer the stage of the shopping process based on touch gestures (segmentation) and guide consumers through the purchase funnel by promoting the use of zoom-page and product-view. Lastly, the findings provide insights into how marketers can promote the use of open-webpage, which has the lowest baseline usage rate yet is crucial for transactions, based on the synergy among touch gestures and through improving the non-native browsing experience.
Worlds of science for children and young people, 1830–1991
Authors: ZILHÃO ISABEL , NIELSEN KRISTIAN H.
Published: August 2018

Science for children and young people is an important, yet often neglected, subject in the historiography of science. It has gained attention due to the growing interest in science popularization. Like popular science, science for children and young people is a historical topic rich in fascinating stories about the ways in which scientific knowledge travels through society and culture. Although children and young people certainly belong to wider audiences for science outside the realm of specialized science, we have come to believe that studying science for children and young people allows us to probe even deeper into the ways in which science interacts with people's lives, their social relations and their hopes for the future. Children and young people since the Enlightenment have come to occupy a special role in Western society, and ideas about humankind, culture, learning, development and science have all been associated with childhood. When adults have presented scientific knowledge to children, they have not only built ideas (often ideals) about social order and proper upbringing into their materials, but also reflected upon questions about science in relation to children's capacity for acquiring new knowledge. We argue that children and young people historically and culturally constitute an important ‘other’ for science, and the historiography of science will benefit from taking on the topic of science for children and young people in this light.
Remarks on Inclusive Comparison
Authors: Diagne Souleymane Bachir
Published: August 2018

At the center of Joseph Slaughter’s important address is the question of inclusion. It appears in the phrase “inclusive comparison.” The remark he makes in a footnote about “non-privileged (generally minor and/or minority) commentators in the world of letters who compared literature from marginal places to the literature from Europe” is particularly interesting as it speaks of pioneers of sort who dared to take seriously the “exhortation to compare” beyond established and conventional borders and bring into the literary conversation other literatures. I would like to develop a few reflections inspired to me by the notion of “inclusive comparison” by examining first the very concept of “comparison” and by considering the lessons to be drawn from the works of a couple of pioneers of “inclusive comparison” bringing in African literature: Abbé Grégoire and Blaise Cendrars.
Life after Oil: The Politics of Labor in Bessora’sPetroleum
Authors: Perisic Alexandra
Published: August 2018

Petroleum, a 2004 novel by Swiss-Gabonese writer Bessora, takes place almost entirely on theOcean Liberator, a ship extracting oil off the coast of Gabon. I argue that theOcean Liberatoroperates as what Marc Augé calls a non-place, a place that cannot be defined in terms of history, identity, or relations. Non-places, frequently under neither national nor international supervision, facilitate the creation of a precarious international labor force. I furthermore underline the relation among the non-place workplace, environmental degradation, and the choice of detective fiction.Petroleumis what I call a supermodern detective novel, which moves beyond local violence to deal with transnational networks of capitalist power and oppression.
Channel planform changes along the Scrivia River floodplain reach in northwest Italy from 1878 to 2016
Authors: Mandarino Andrea , Maerker Michael , Firpo Marco
Published: August 2018

A detailed, quantitative, multitemporal analysis of historical maps, aerial photos, and satellite images was performed to investigate the channel planform changes that occurred along the Scrivia River floodplain from 1878 to 2016. Various channel planform features, including channel length, area, width, braiding, sinuosity, lateral migration, activity, and stability, were computed through an innovative geographic information system–based procedure, starting from manually digitized active-channel polygons. Three active-channel morphological evolution stages are evident from: (1) 1878 to the 1950s; (2) the 1950s to the end of 1990s; and (3) the end of 1990s onward. In the first period, the river was generally able to migrate in its floodplain, shaping the riverscape. Active-channel narrowing and increasing channel stability characterize the second period. The most recent phase shows an inversion of the morphological evolutionary trend. This last phase is characterized by a slight generalized widening related to the reactivation of stabilized surfaces and to bank-erosion processes. Particularly from the 1950s to the 1990s, in-channel sediment mining and channelization with consequent occupation of riverine areas strongly affected the Scrivia River. These factors, together with floods, are thought to be the most likely causes of such consistent and fast morphological changes.
Lorentz invariant ‘potential magnetic field’ and magnetic flux conservation in an ideal relativistic plasma
Authors: Pegoraro F.
Published: August 2018

A family of Lorentz invariant scalar functions of the magnetic field is defined in an ideal relativistic plasma. These invariants are advected by the plasma fluid motion and play the role of the potential magnetic field introduced by Hide in (Ann. Geophys., vol. 1, 1983, 59) along the lines of Ertel’s theorem. From these invariants we recover the Cauchy conditions for the magnetic field components in the mapping from Eulerian to Lagrangian variables. In addition, the adopted procedure allows us to formulate, in a Lorentz invariant form, the Alfvén theorem for the conservation of the magnetic flux through a surface comoving with the plasma.
Genetic and environmental influences on disinhibition, boldness, and meanness as assessed by the triarchic psychopathy measure in 19–20-year-old twins
Authors: Tuvblad Catherine , Wang Pan , Patrick Christopher J. , Berntsen Leslie , Raine Adrian , Baker Laura A.
Published: August 2018

Background

The Triarchic Psychopathy Measure (TriPM) provides Disinhibition, Boldness, and Meanness scales for assessing the three trait domains of the triarchic model. Here we examined the genetic and environmental etiology of these three domains, including evaluation of potential sex differences.

Methods

A total of 1016 men and women ages 19–20 years were drawn from the University of Southern California Risk Factors for Antisocial Behavior twin study.

Results

Scores for the three TriPM scales were correlated to differing degrees, with the strongest phenotypic correlation between Disinhibition and Meanness. No sex differences were found in the genetic and environmental influences underlying these three domains, suggesting that the same genes and life experiences contribute to these traits in young men and women. For TriPM Disinhibition and Boldness, genetic factors explained about half or less of the variance, with the rest of the variance being explained by non-shared environmental factors. For TriPM Meanness, on the other hand, genetic, shared environmental, and non-shared environmental factors accounted for the variance. The phenotypic correlation between Disinhibition and Meanness was explained in part by common genes (26%), with the remainder attributable about equally to common shared (39%), and non-shared environmental influences (35%).

Conclusions

These findings contribute to our understanding of psychopathic personality traits by demonstrating the importance of heritable factors for disinhibition and boldness facets of psychopathy, and the importance of shared environmental influences for the meanness facet.
Social transmission bias and the cultural evolution of folk-economic beliefs
Authors: Hirshleifer David , Teoh Siew Hong
Published: August 2018

Evolved dispositions influence, but do not determine, how people think about economic problems. The evolutionary cognitive approach offers important insights but underweights the social transmission of ideas as a level of explanation. The need for asocialexplanation for the evolution of economic attitudes is evidenced, for example, by immense variations in folk-economic beliefs over time and across individuals.
Why do people believe in a zero-sum economy?
Authors: Johnson Samuel G. B.
Published: August 2018

Zero-sum thinking and aversion to trade pervade our society, yet fly in the face of everyday experience and the consensus of economists. Boyer & Petersen's (B&P's) evolutionary model invokes coalitional psychology to explain these puzzling intuitions. I raise several empirical challenges to this explanation, proposing two alternative mechanisms – intuitive mercantilism (assigning value to money rather than goods) and errors in perspective-taking.
Broadening the role of “self-interest” in folk-economic beliefs
Authors: Karabegović Mia , Rotella Amanda , Barclay Pat
Published: August 2018

We extend Boyer & Petersen's (B&P's) model of folk-economic beliefs (FEBs) by suggesting FEBs serve self-interest (broadly defined), which includes indirect benefits such as creating alliances, advancing self-beneficial ideologies, and signaling one's traits. By expanding the definition of self-interest, the model can predict who will hold what FEBs, which FEBs will propagate, when they will change, why, and in which direction.
Understanding the development of folk-economic beliefs
Authors: Liberman Zoe , Kinzler Katherine D.
Published: August 2018

Developmental psychology can shed light on (1) the intuitive systems that underlie folk-economic beliefs (FEBs), and (2) how FEBs are created and revised. Boyer & Petersen (B&P) acknowledge the first, but we argue that they do not seriously consider the second. FEBs vary across people (and within a person), and much of this variation may be explained by socialization, social context, and social learning.
A theory of how evolved psychology underpins attitudes towards societal economics must go beyond exchanges and averages
Authors: Sheehy-Skeffington Jennifer , Thomsen Lotte
Published: August 2018

We applaud Boyer & Petersen for the advancement of an ultimate explanation of the dynamics of folk-economic beliefs and the political actions linked to them. To our mind, however, key inference systems regulating societal interaction and resource distribution evolved for more core relations than those of proportionate exchange, and situational factors are not the only constraints on how such systems produce economic beliefs
A FATAL FLAW: DOMESTIC BANKS AND MEXICO’S INTERNATIONAL NEGOTIATING POSITION IN THE 1982 DEBT CRISIS
Authors: Alvarez Sebastian
Published: August 2018

The recent European debt crisis has renewed interest as to why debtor countries honour their foreign debts and subscribe to respectively burdensome rescheduling conditions. While the cost of defaulting in a domestic financial system has been recognised as a main motive for repayment, the factors that cause sovereign states to refrain from debt repudiation are not fully understood. This article investigates the reasons behind the repayment decision and weak negotiating position of the Mexican government following the 1982 debt crisis. It shows that leading commercial banks had considerable amounts of external loans in their books, and that Mexican policymakers lacked the foreign exchange access they needed to secure the stability of the domestic banking system. The high exposure of domestic banks to Mexican debt and their heightened dependence on foreign capital worked as mechanisms that allowed international creditors to enforce their claims and deterred Mexico from declaring a unilateral default.
Retirement Transitions among Baby Boomers: Findings from an Online Qualitative Study
Authors: Genoe M. Rebecca , Liechty Toni , Marston Hannah R.
Published: August 2018

En 2011, les baby-boomers canadiens ont commencé à franchir la barre des 65 ans, ou l’âge traditionnel de la retraite. Il est possible que la perception et l’expérience de la retraite s’avèrent différentes dans cette génération, comparativement aux générations précédentes. Le but de cet article est d’explorer les tendances dans la transition vers la retraite de baby-boomers en Saskatchewan, en lien avec les phases qu’ils ont traversées au cours de cette transition. Dans cette étude effectuée en ligne selon un modèle de théorie ancrée, 25 baby-boomers approchant de la retraite ou récemment retraités ont participé à un blogue multi-auteurs où ils ont partagé leurs expériences et les processus liés à leur retraite. Des données additionnelles ont été collectées dans le cadre d’entrevues et de groupes de discussion réunissant les participants après la fin de leur participation au blogue. Les participants ont adopté différents modèles dans leur processus de retraite, certains arrêtant de travailler, d’autres poursuivant leurs activités professionnelles dans le cadre de travaux occasionnels ou à temps partiel, ou en effectuant d’autres types de travaux. Les résultats ont mis en évidence 3 phases dans la transition vers la retraite : la préretraite, caractérisée à la fois par certaines craintes liées à la retraite et par l’idéalisation de la retraite parfaite, suivie de la transition initiale, au cours de laquelle les participants ont comparé la retraite à des vacances prolongées, au cours desquelles ils ont peiné à s’adapter à l’augmentation de leur temps libre, pour enfin arriver à une transition de moyen terme où ils ont appris à équilibrer structure et flexibilité. Les résultats suggèrent que bien que la transition vers la retraite présente plusieurs défis, plusieurs personnes rapportent des visions et des expériences positives de cette transition.
Incidence of cardiovascular diseases in a nationwide HIV/AIDS patient cohort in Taiwan from 2000 to 2014
Authors: Lai Yun-Ju , Chen Yu-Yen , Huang Hsin-Hui , Ko Ming-Chung , Chen Chu-Chieh , Yen Yung-Feng
Published: August 2018

The purpose of the study was to determine the incidence of cardiovascular disease (CVD) among people living with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (PLWHA) in Taiwan. PLWHA were identified from the Taiwan Centers for Disease Control HIV Surveillance System between 2000 and 2014. To examine the effect of active antiretroviral therapy (HAART) on CVD incidence, incidence densities and standardised incidence rates (SIRs) of CVD were calculated after stratifying PLWHA by HAART. Of 26 272 PLWHA (mean age, 32.3 years) identified, 73.4% received HAART. Compared with general population, SIRs (95% confidence interval) were higher for incident coronary artery disease (1.11 (1.04–1.19)), percutaneous coronary intervention (1.32 (1.18–1.47)), coronary artery bypass surgery (1.47 (1.29–1.66)), sudden cardiac death (3.01 (2.39–3.73)), heart failure (1.50 (1.31–1.70)) and chronic kidney disease (1.95 (1.81–2.10)), but was lower for incident atrial fibrillation (0.53 (0.37–0.73)). Considering the effect of HAART on incident CVD, the SIRs for all-cause, ischaemic and haemorrhagic stroke were higher in PLWHA who did not receive HAART, but were lower in PLWHA who received HAART. PLWHA had higher risks of incident coronary artery disease, percutaneous coronary intervention, coronary artery bypass surgery, sudden cardiac death, heart failure and chronic kidney disease. HAART reduces risks of incident CVD in PLWHA.
Use of added sugars in packaged foods sold in Brazil
Authors: Scapin Tailane , Fernandes Ana Carolina , dos Anjos Adilson , Proença Rossana Pacheco da Costa
Published: August 2018

Objective

Studies have shown that the consumption of added sugars may be associated with harmful health effects. The present study investigated the presence and types of added sugars in packaged foods.

Design

Cross-sectional analysis of the presence and types of added sugars in the ingredients lists of packaged foods sold in a major Brazilian supermarket. The nomenclature of ingredients classified as added sugars and their frequency were identified. Data were organised and analysed through descriptive statistics: absolute and relative frequencies of the presence of added sugars categorised by food groups were calculated, and ingredients were analysed by text mining using R statistical environment.

Setting

A supermarket in Florianópolis, a metropolis in southern Brazil.

Subjects

Packaged food products (n 4539) classified into eight groups.

Results

Of the 4539 products, 71 % had some type of added sugar. The group with the highest frequency of added sugars was ‘products in which carbohydrates and fats are the main energy source’ (93 %). Food groups containing predominantly salty foods had a high frequency of added sugars, such as ‘meats and eggs’ (61 %). In total, 179 different terms for added sugars were identified, of which sugar, maltodextrin and glucose syrup were the most frequent.

Conclusions

Most of the packaged foods sold in Brazil contain added sugars, which may hamper adherence to the recommendation of limiting added sugars intake. The data may be useful for monitoring tendencies in the use of added sugars in packaged foods and as supplementary information to support the improvement of food label regulations.
What Are the Key Catchment Characteristics Affecting Spatial Differences in Riverine Water Quality?
Authors: Lintern A. , Webb J. A. , Ryu D. , Liu S. , Waters D. , Leahy P. , Bende‐Michl U. , Western A. W.
Published: August 2018

This study uses water‐quality data collected over 20 years, from 102 predominantly rural sites across Victoria, Australia, to further our understanding of spatial variability in riverine water quality. We focus on concentrations of total suspended solids, total phosphorus, filterable reactive phosphorus, total Kjeldahl nitrogen, nitrate/nitrite (NOx), and electrical conductivity. We used an exhaustive search approach to identify the linear models that best link catchment characteristics to time‐averaged constituent concentrations. We ran additional analyses to (1) assess the performance of these models under drought conditions, and (2) understand the key drivers of site‐level variability (standard deviations) of constituent concentrations. Natural catchment characteristics appear to have a greater effect on spatial differences in average constituent concentrations. Performance of the statistical models of time‐averaged constituent concentrations varied, and spatial variability in mean electrical conductivity levels could be more readily explained by catchment characteristics compared to more reactive nutrients. Notwithstanding, the models performed relatively well under varying hydrologic conditions for most constituents. As such, these models provide an insight into the key factors affecting spatial variability in average stream water‐quality conditions. We also identified that hydrologic, climatic, and topographic characteristics of the catchment helped explain the spatial variability in temporal changes in constituents. After calibration and validation, these models of both average water quality and variability in water quality could be used to forecast stream water‐quality responses to future land use, climate, or soil and land management changes.
Evaluation of Nonparametric and Parametric Statistical Procedures for Modeling and Prediction of Cluster‐Correlated Hydroclimatic Data
Authors: Singh Sarmistha , Abebe Ash , Srivastava Puneet
Published: August 2018

Climate and hydrologic variables such as temperature, precipitation, streamflow, and baseflow generally do not follow Gaussian distribution due to the presence of outliers and heavy tails. Therefore, they are usually analyzed using the nonparametric Wilcoxon rank sum test rather than parametric methods like classical t tests and analysis of variance. Furthermore, in addition to having a non‐Gaussian distribution, these data exhibit monthly/seasonal variability, which leads to within month/season cluster correlation. In this study, a nonparametric procedure, called joint rank fit (JRFit), for analyzing cluster‐correlated data was implemented and compared against traditional methods such as restricted maximum likelihood, least absolute deviations, and rank‐based fit (a model‐based extension of Wilcoxon rank sum) for studying the coupled effect of the phases of El Niño–Southern Oscillation and Atlantic Multidecadal Oscillation on baseflow levels. The results from a large Monte Carlo simulation experiment showed that JRFit was more efficient than the other three methods for data with (i) high variability, (ii) outliers due to contamination, or (iii) strong monthly/seasonal correlation. The efficiency gain of JRFit was up to 50% compared to restricted maximum likelihood for heavy‐tailed and highly correlated data. Predictive performance evaluated using the mean absolute prediction error and mean prediction standard error from an out‐of‐sample cross‐validation study showed JRFit to be optimal for providing predictions of baseflow on the basis of the phases of El Niño–Southern Oscillation and Atlantic Multidecadal Oscillation. Thus, it is recommended that JRFit be implemented in hydroclimatic studies to provide powerful inference when there is evidence of clustering in the data.
Scientists Meet to Review Preparations for Satellite Launch
Authors: Atkins Tom , Divakarla Murty , Zhou Lihang
Published: August 2018

Center for Satellite Applications and Research JPSS 2017 Annual Science Team Meeting; College Park, Maryland, 14–18 August 2017
Watching Dehydration: Seismic Indication for Transient Fluid Pathways in the Oceanic Mantle of the Subducting Nazca Slab
Authors: Bloch Wasja , John Timm , Kummerow Jörn , Salazar Pablo , Krüger Oliver S. , Shapiro Serge A.
Published: August 2018

Intermediate depth seismicity in subduction zones often occurs in the form of two slab‐parallel bands. We estimated the seismic P to S wave velocity ratio within the shallowest part of the lower seismicity zone (LSZ) in the mantle of the subducting slab of the Central Andean subduction system at 50‐km depth, 30 km below the Moho, using local earthquake data. We find an exceptionally high VP/VS value larger than ∼2.0 that cannot be explained by a realistic solid lithology but requires the presence of fluid‐filled porosity. This implies that the incoming Nazca plate must be partially hydrated to this depth below the seafloor. We introduce a state‐of‐the‐art petrophysical model that takes into account the thermodynamic and poroelastic effects of dynamic metamorphic mineral dehydration at 1.8 GPa and consider anisotropic effects. The model shows that a high VP/VS value generally indicates that the medium is near the percolation threshold, that is, that porosity must be interconnected. This result is consistent with observations from outcrops of paleosubduction zones, laboratory experiments, and numerical simulations. It follows that the shallowest part of the LSZ of the Central Andes must reside at a temperature at which mineral dehydration reactions take place, here between 430 and 500 ° C. For the first time, we can confirm that the observations of transient dehydrating fluid‐filled vein structures with a pore volume in the order of only 10−3 are reasonable for the LSZ and enough to allow for effective drainage.
The Influence of Oceanic Stochastic Forcing on the Atmospheric Response to Midlatitude North Pacific SST Anomalies
Authors: Sun Xuguang , Tao Lingfeng , Yang Xiu‐Qun
Published: August 2018

The stochastic sea surface temperature (SST) anomalies are always present because of the internal oceanic variability due to small‐scale SST variability and based on a set of ensemble experiments forced by Pacific Decadal Oscillation‐related midlatitude North Pacific SST anomalies with and without oceanic stochastic forcing, their influences on atmospheric variability in coarse‐resolution models are investigated in this study. Comparisons of experiment results show that oceanic stochastic forcing can improve the simulated atmospheric response by generating more organized atmospheric transient eddies through the increases of both thermal activity and atmospheric baroclinicity, similar to the high‐resolution observations and simulations. Dynamic diagnostics further reveal the dominant contributions of corresponding transient eddy vorticity forcing to the significantly enhanced westerly wind with equivalent barotropic structure. It suggests that the oceanic stochastic forcing is important and nonnegligible for the understanding and theory of oceanic feedback to the atmosphere in the midlatitudes.
Global Estimates of Changes in Shortwave Low‐Cloud Albedo and Fluxes Due to Variations in Cloud Droplet Number Concentration Derived From CERES‐MODIS Satellite Sensors
Authors: Painemal David
Published: August 2018

Fifteen years of Aqua Clouds and the Earth's Radiant Energy Systems (CERES) and MOderate resolution Imaging Spectroradiometer (MODIS) observations are combined to derive nearly global maps of shortwave albedo (A) and flux (F) response to changes in cloud droplet number concentration (Nd). Absolute (
) and relative (
) albedo susceptibilities are computed by exploiting the linear relationship between A and ln (Nd) for shallow liquid clouds. Subtropical stratiform clouds over the eastern Pacific, eastern Atlantic, and off the coast of eastern Asia yield the highest Sr, followed by the extratropical oceans during their hemispheric summer. When Sr is cast in terms of F, the eastern Pacific clouds dominate Sr. Sa is mainly governed by Nd, with offshore clouds producing high Sa. While both Sa and Sr are advantageous for understanding radiative aspects of the aerosol indirect effect, Sr is more suitable for calculating changes in A and F due to the linearity of the A‐ln (Nd) relationship.
High‐Frequency Intermittency in Observed and Model‐Simulated Precipitation
Authors: Covey Curt , Doutriaux Charles , Gleckler Peter J. , Taylor Karl E. , Trenberth Kevin E. , Zhang Yongxin
Published: August 2018

A newly reprocessed, bias‐corrected version of hourly satellite observations that provides global coverage of precipitation at high space‐time resolution is evaluated and compared with climate model simulations. Irregular subdaily fluctuations are the dominant component around the world, greater than variance of daily mean precipitation, and much greater than variance associated with the mean diurnal cycle of precipitation. Irregular subdaily fluctuations of precipitation are severely underestimated by models, even after taking into account the observational “error bars” implied by different space‐time resolutions. Variance of daily mean precipitation is less severely underestimated. Although mean diurnal cycle amplitudes vary among the models, this component is but a small part of total precipitation variance. Therefore, the total precipitation variance is significantly underestimated by models in general. Further exploration of model‐data discrepancies in precipitation at high‐time frequency may lead to new and useful climate model diagnostics.
Off‐Fault Focal Mechanisms Not Representative of Interseismic Fault Loading Suggest Deep Creep on the Northern San Jacinto Fault
Authors: Cooke M. L. , Beyer J. L.
Published: August 2018

Within the San Bernardino basin, some focal mechanisms show normal slip that is inconsistent with the expected interseismic strike‐slip loading of the region. The discrepancy may owe to deep (>10‐km depth), creep along the nearby northern San Jacinto fault. The enigmatic normal slip microseismicity occurs to the northeast of the fault and primarily below 10‐km depth, consistent with off‐fault deformation due to spatially nonuniform ongoing slip. Consequently, if these normal focal mechanisms are included in stress inversions from the seismic catalog, the results may provide inaccurate information about fault loading. Here we show that off‐fault loading from models with deep interseismic creep on the northern San Jacinto fault match the first‐order pattern of observed normal slip focal mechanisms in the basin and that this deep creep cannot be detected with GPS data due to the proximity of the San Andreas fault.
Nocturnal Thermal Fracturing of a Himalayan Debris‐Covered Glacier Revealed by Ambient Seismic Noise
Authors: Podolskiy Evgeny A. , Fujita Koji , Sunako Sojiro , Tsushima Akane , Kayastha Rijan B.
Published: August 2018

Scientifically valuable information can be learned by listening to the tiny vibrations emanating from a glacier with seismometers. However, this approach has never been employed to better understand glaciers protected from heat by a debris mantle, despite being common in the Himalayas, one of the most glacierized regions in the world. Here we installed a seismic network at a series of challenging high‐altitude sites on a glacier in Nepal. Our results show that the diurnal air temperature modulates the glacial seismic noise. The exposed surface of the glacier experiences thermal contraction when the glacier cools, whereas the areas that are insulated with thick debris do not suffer such thermal stress. Thus, the unprotected ice surface bursts with seismicity every night due to cracking, which gradually damages and weathers the ice. This is the first time such processes have been observed at relatively warm temperatures and outside of the polar regions.
Effects of a Weak Intrinsic Magnetic Field on Atmospheric Escape From Mars
Authors: Sakai Shotaro , Seki Kanako , Terada Naoki , Shinagawa Hiroyuki , Tanaka Takashi , Ebihara Yusuke
Published: August 2018

The magnetization of a planet significantly changes the nature of atmospheric escape, and the question of whether a planetary field shields atmosphere from erosion by the solar wind or not remains open. Ion escape processes from Mars are investigated under two hypothetical conditions, namely, no intrinsic magnetic field and weak intrinsic dipole field cases under present solar wind conditions based on multispecies magnetohydrodynamics simulations. The existence of a weak dipole field results in an enhancement of the tailward flux of planetary ions through the four escape channels. Two channels are associated with the open fields at the poles, and the others are caused by magnetic reconnection between the planetary and solar wind magnetic fields at the flank magnetopause. The ion escape rate with the weak dipole is greater than in the no‐dipole case. The enhancement is significant for O2+ and CO2+, suggesting ion escape from the low‐altitude ionosphere.
Surface Creep Rate of the Southern San Andreas Fault Modulated by Stress Perturbations From Nearby Large Events
Authors: Xu Xiaohua , Ward Lauren A. , Jiang Junle , Smith‐Konter Bridget , Tymofyeyeva Ekaterina , Lindsey Eric O. , Sylvester Arthur G. , Sandwell David T.
Published: August 2018

A major challenge for understanding the physics of shallow fault creep has been to observe and model the long‐term effect of stress changes on creep rate. Here we investigate the surface creep along the southern San Andreas fault (SSAF) using data from interferometric synthetic aperture radar spanning over 25 years (ERS 1992–1999, ENVISAT 2003–2010, and Sentinel‐1 2014–present). The main result of this analysis is that the average surface creep rate increased after the Landers event and then decreased by a factor of 2–7 over the past few decades. We consider quasi‐static and dynamic Coulomb stress changes on the SSAF due to these three major events. From our analysis, the elevated creep rates after the Landers can only be explained by static stress changes, indicating that even in the presence of dynamically triggered creep, static stress changes may have a long‐lasting effect on SSAF creep rates.
Evolution of Freshly Generated Equatorial Spread F (F‐ESF) Irregularities on Quiet and Disturbed Days
Authors: Gurram P. , Kakad B. , Bhattacharyya A. , Pant T. K.
Published: August 2018

We examined the seasonal and solar flux dependence of the occurrence of freshly generated intermediate scale (100 m to few km) equatorial spread F (ESF) irregularities during magnetically quiet (Q) and disturbed (D) periods. We utilized long‐term (1992–2006 and 2013–2015) amplitude scintillation data on a 251 MHz signal recorded at Tirunelveli (dip lat. 1.5°N ). Also, ionosonde data (1990–2003) recorded at Trivandrum (dip lat. 0.5°N) are used. The presence of fresh ESF (F‐ESF) is identified using the maximum cross‐correlation between intensity variations recorded by two spaced receivers on a magnetic east‐west baseline. We find distinct differences in the seasonal and solar flux dependence of the usual postsunset (<22 LT) generation of F‐ESF on both Q‐ and D‐days. Interesting feature is that F‐ESF linked moderate–strong scintillations are more prevalent on D‐days as compared to Q‐days in both early (18–22 LT) and later (>22 LT) phase of evolution of the irregularities. It directly hints toward the difference in the spatial structuring (spatial scales) of F‐ESF on D‐days as compared to Q‐days. On D‐days, the occurrence of F‐ESF is more likely around midnight and early‐morning hours in all seasons. Whereas on Q‐days, the postmidnight F‐ESF is found to occur mainly during solstices of low solar activity. The possible sources for the generation of F‐ESF around midnight on Q‐days of solstices during low solar activity are examined. We also find that perturbation electric field linked with F‐ESF on D‐days sustains for longer time, which results in longer durations of the active phase of equatorial plasma bubbles.
The Acceleration of Electrons to High Energies Over the Jovian Polar Cap via Whistler Mode Wave‐Particle Interactions
Authors: Elliott S. S. , Gurnett D. A. , Kurth W. S. , Mauk B. H. , Ebert R. W. , Clark G. , Valek P. , Allegrini F. , Bolton S. J.
Published: August 2018

Upward traveling electrons with energies from tens of kiloelectron volts to several megaelectron volts have been observed over the Jovian polar regions in association with intense upward propagating whistler mode waves. The electrons have a power law‐like energy distribution, indicative of a stochastic acceleration process. The energy flux of the upward propagating whistler mode waves is comparable to and strongly correlated with the energy flux of the upward traveling energetic electrons, suggesting that the whistler mode waves may be accelerating the electrons. We propose that a downward field‐aligned current over the polar cap generates strong downward parallel electric fields and associated upward electron beams in the low‐density regions of Jupiter's upper ionosphere, a mechanism similar to the formation of inverted‐Vs in Earth's auroral regions. At Jupiter, the upward‐traveling electron beams produce intense upward propagating whistler mode emissions over a broad frequency range, similar to upward propagating auroral hiss at Earth. As the whistler mode waves propagate upward out of the inverted‐V source region, the waves are absorbed by the plasma, thereby accelerating the electrons. We attribute the stochastic power law‐like energy spectrum of the accelerated electrons to the development of Hamiltonian chaos (velocity space diffusion), the signature of which is indicated by the occurrence of spiky soliton‐like variations in the whistler mode electric fields. Acceleration to high energies may be facilitated by the rapid increase in the phase velocity of the whistler mode waves with increasing altitude, which could accelerate some of the electrons trapped in the wavefield to very high relativistic energies.
Slip‐Deficit Rate Distribution Along the Nankai Trough, Southwest Japan, With Elastic Lithosphere and Viscoelastic Asthenosphere
Authors: Noda Akemi , Saito Tatsuhiko , Fukuyama Eiichi
Published: August 2018

In southwest Japan, great earthquakes have occurred on the plate interface along the Nankai trough with a recurrence time of approximately 100 years. Most previous studies estimated slip deficits on the seismogenic zone from interseismic Global Navigation Satellite System (GNSS) velocity data assuming slip‐response functions for an elastic medium. The observed surface velocities, however, include effects of viscoelastic relaxation in the asthenosphere caused by slip motion associated with seismic cycles. If the elastic responses cannot adequately approximate the deformation of the viscoelastic medium, the results of an inversion analysis could be biased. If the recurrence interval is greater than the effective relaxation time in the elastic‐viscoelastic layered structure, we were able to formulate an inverse problem for the estimation of slip‐deficit rates from GNSS velocity data with completely relaxed slip‐response functions for a later stage of the seismic cycle. Analyzing surface velocity data from GNSS daily coordinate data between March 2005 and February 2011 together with seafloor geodetic data, we estimated the slip‐deficit rate distribution by the strain data inversion method. There were significant differences between the results using elastic and completely relaxed responses. Although the result with elastic responses shows a high coupling zone in the coastal region, it was located trenchward when completely relaxed responses were used. We found that the peak slip‐deficit rate increases as the thickness of the lithosphere becomes thinner. Moreover, we succeeded in appropriately separating elastic‐viscoelastic deformation due to plate coupling from rigid block motion.
Exploration of Tidal‐Fluvial Interaction in the Columbia River Estuary Using S_TIDE
Authors: Pan Haidong , Lv Xianqing , Wang Yingying , Matte Pascal , Chen Haibo , Jin Guangzhen
Published: August 2018

Numerous tidal phenomena, including river tides, internal tides, and tides in ice‐covered bay, are nonstationary, which pose a great challenge for traditional tidal analysis methods. Based on the independent point scheme and cubic spline interpolation, a new approach, namely the enhanced harmonic analysis, is developed to deal with nonstationary tides. A MATLAB toolbox, S_TIDE, developed from the widely used T_TIDE, is used to realize the approach. The efficiency of S_TIDE is validated by analyzing a set of hourly water level observations from stations on the lower Columbia River. In all stations, the hindcast of S_TIDE is more accurate than NS_TIDE that is a powerful nonstationary tidal analysis tool adapted to river tides. The changing mean water level and tidal constituent properties obtained by S_TIDE are similar to those obtained by NS_TIDE, continuous wavelet transform, and empirical mode decomposition and highly consistent with theory on river tides. Moreover, different from NS_TIDE that only can be applied to river tides, enhanced harmonic analysis is free of dynamic content, assuming only known tidal frequencies. Therefore, S_TIDE can be applied to all kinds of nonstationary tides theoretically. Though powerful, S_TIDE also has some limitations: S_TIDE cannot be used for prediction and too many independent points in S_TIDE may induce computational memory overflow and unrealistic results.