bluuebunny/crossref_metadata_2025 huggingface dataset:
A hybrid virtual network mapping algorithm based on threshold load
Authors: Liu Zhiguo , Qin Lingyu , Liu Qingli , Liu Junmei , Ding Yuanming
Published: August 2018

The virtual resource management architecture for satellite networks currently suffers from a very poor virtual network mapping success rate. This arises because of the need to map multiple heterogeneous virtual networks to the underlying satellite network. Most heuristic algorithms divide virtual network mapping into node mapping and link mapping, which aims to reduce the complexity of the problem. However, this approach is not well suited to highly dynamic satellite networks. In this paper, we propose a hybrid virtual network mapping algorithm that is based on threshold load. This takes the overall load for the nodes as its optimization objective, and combines the idea of backtracking contained in 1‐stage mapping methods and the idea of global optimization contained in 2‐stage mapping methods. The algorithm reduces the complexity of backtracking computation, while avoiding any incompleteness that might result from separating nodes and link mapping. The success rate for virtual network mapping is thus improved, as is the utilization rate for satellite network resources.
Fighting the inevitable: infrastructure investment and coastal community adaptation to sea level rise
Authors: Woodruff Sierra , BenDor Todd K. , Strong Aaron L.
Published: August 2018

Coastal communities are crafting adaptation strategies to confront sea level rise (SLR). Unfortunately, cost–benefit analyses that assess SLR risks often fail to capture important political and social feedbacks. For example, adaptation measures (e.g., beach nourishment) can trigger greater development, undermining the value of adaptation infrastructure, incentivizing development, and increasing risks. We integrate diverse literature and data to develop a hypothesis and system dynamics model of coastal community responses to SLR. We apply the model to two U.S. communities, showing how political influence drives trajectories of infrastructure provision, cost, and vulnerability. We find that delayed feedbacks between perceived SLR risk and infrastructure investments mediate relationships between political capital, migration, and economic development. Community wealth and political influence may only delay the overshoot and collapse of its population and economy, as the “virtuous cycles” linking growth with infrastructure investment give way to “vicious cycles” of mounting infrastructure costs, political resistance to additional investment, and greater vulnerability.

Copyright © 2018 System Dynamics Society
Relaxed covariate overlap and margin‐based causal effect estimation
Authors: Ghosh Debashis
Published: August 2018

In most nonrandomized observational studies, differences between treatment groups may arise not only due to the treatment but also because of the effect of confounders. Therefore, causal inference regarding the treatment effect is not as straightforward as in a randomized trial. To adjust for confounding due to measured covariates, a variety of methods based on the potential outcomes framework are used to estimate average treatment effects. One of the key assumptions is treatment positivity, which states that the probability of treatment is bounded away from zero and one for any possible combination of the confounders. Methods for performing causal inference when this assumption is violated are relatively limited. In this article, we discuss a new balance‐related condition involving the convex hulls of treatment groups, which I term relaxed covariate overlap. An advantage of this concept is that it can be linked to a concept from machine learning, termed the margin. Introduction of relaxed covariate overlap leads to an approach in which one can perform causal inference in a three‐step manner. The methodology is illustrated with two examples.
Prevalence of thermotolerant Campylobacter species in dogs and cats in Iran
Authors: Torkan Saam , Vazirian Behnam , Khamesipour Faham , Dida Gabriel O.
Published: August 2018

Campylobacter is considered the most common bacterial cause of human gastroenteritis in the world with C. jejuni being regarded as the primary cause of bacterial gastroenteritis. A broad range of other Campylobacter species, including C. coli have also been implicated in human gastroenteritis. This study sought to isolate, characterize and assess the antibiogram of Campylobacter jejuni and C. coli from faecal samples obtained from cats and dogs in Isfahan and Shahrekord cities in Iran. Faecal samples were collected from 100 pets comprising of 50 dogs and 50 cats from March 2015 to March 2016; incorporating the four seasons (spring, summer, autumn and winter). Campylobacter spp. was isolated by culture, characterized by biochemical tests and confirmed by PCR‐based assays. Antimicrobial susceptibility test was performed by the Kirby–Bauer disk diffusion method, using Mueller Hinton agar. A total of 19 Campylobacter isolates among them two C. jejuni and one C. coli were recovered from dogs and cats’ faecal samples. The prevalence rates of Campylobacter spp. were 16.0% (8 out of 50) in dogs and 22.0% (11 out of 50) in cats. The highest (4 out of 16, 25%) Campylobacter spp. prevalence among dogs was reported in autumn and the lowest (1 out of 11, 9.1%) in spring, while among the cats, the highest (4 out of 12, 33.3%) Campylobacter spp. prevalence was reported in summer and lowest (1 out of 11, 9.09%) in spring. Campylobacter spp. isolated from faecal samples obtained from cats and dogs exhibited the most frequent antimicrobial resistance against tetracycline at 81.8% and 87.5%, respectively, compared to all other antimicrobial agents. These results show a low prevalence of Campylobacter spp. in faecal samples obtained from pet dogs and cats in Shahrekord and Isfahan cities in Iran. Given the relatively low prevalence of the C. jejuni and C. coli in pet dogs and cats in Isfahan and Shahrekord cities, it can be assumed that their importance as reservoirs for infection in humans is likely to be limited to the studied cities, but should not be neglected.
Reactivity of a Bulky Bora‐Amidine Ligand with Trimethylaluminum
Authors: Zijlstra Harmen S. , Hofmann Alexander , Harder Sjoerd
Published: August 2018

Reaction of Me3Al with HB[N(H)DIPP]2 (DIPP = 2,6‐iPr2‐C6H3) in hexane gave a complex mixture of compounds instead of HB(N‐DIPP)2AlMe. After addition of THF, one of the products could be trapped in trace amounts and was characterized by crystal structure determination: DIPP–N(H)B(H)(N–DIPP)AlMe2·THF (1). Heating a hexane or fluorobenzene solution of HB[N(H)DIPP]2 and Me3Al in the absence of THF gave a relatively clean conversion and allowed for the isolation of [(DIPPNH)AlMe2(μ‐H)AlMe2]2 (2), a product that was formed through B/Al ligand exchange. Complex 2 contains protic and hydridic hydrogen atoms in close vicinity. The compound remains intact upon heating, however, it readily releases H2 when dissolved in THF forming DIPPN(AlMe2·THF)2 (3). The latter bimetallic complex contains two THF stabilized Lewis acidic central aluminum atoms in close proximity.
Superstrings on AdS3 at k = 1
Authors: Giribet G. , Hull C. , Kleban M. , Porrati M. , Rabinovici E.
Published: August 2018

Abstract

We study superstring theory in three dimensional Anti-de Sitter spacetime with NS-NS flux, focusing on the case where the radius of curvature is equal to the string length. This corresponds to the critical level k = 1 in the formulation as a Wess-Zumino-Witten model. Previously, it was argued that a transition takes place at this special radius, from a phase dominated by black holes at larger radius to one dominated by long strings at smaller radius. We argue that the infinite tower of modes that become massless at k = 1 is a signal of this transition. We propose a simple two-dimensional conformal field theory as the holographic dual to superstring theory at k = 1. As evidence for our conjecture, we demonstrate that our putative dual exactly reproduces the full spectrum of the long strings of the weakly coupled string theory, including states unprotected by supersymmetry.
Relation Between Religious Perspectives and Views on Sickle Cell Disease Research and Associated Public Health Interventions in Ghana
Authors: Dennis‐Antwi Jemima A. , Ohene‐Frempong Kwaku , Anie Kofi A. , Dzikunu Helen , Agyare Veronica A. , Okyere Boadu Richard , Sarfo Antwi Joseph , Asafo Mabel K. , Anim‐Boamah Oboshie , Asubonteng Augustine K. , Agyei Solomon , Wonkam Ambroise , Treadwell Marsha J.
Published: August 2018

Sickle cell disease (SCD) is highly prevalent in Africa with a significant public health burden for under‐resourced countries. We employed qualitative research methods to understand the ethical, legal, and social implications of conducting genomic research in SCD under the Human Heredity and Health in Africa (H3Africa) initiative. The present study focused on religious and cultural aspects of SCD with the view to identifying beliefs and attitudes relevant to public health interventions in Ghana. Thematic analyses from individual and group interviews revealed six key areas of importance, namely, reliance on a supreme being; religion as a disruptive influence on health behaviors; role of religious leaders in information sharing and decision‐making; social, religious, and customary norms; health and religious/supernatural beliefs; and need for social education and support through church and community. Findings suggest that public health programs in Ghana should not only aim at increasing knowledge and awareness about SCD and its management but also create an understanding of the relevance of genomics and alternative technological advancement to diagnosis and ethical decision‐making around available options for health seeking. Future research should engage communities to help address the ethical and social implications of a persuasive religious influence on SCD‐related health decisions.
Bifurcation to locked fronts in two component reaction–diffusion systems
Authors: Faye Grégory , Holzer Matt
Published: August 2018

We study invasion fronts and spreading speeds in two component reaction–diffusion systems. Using a variation of Lin's method, we construct traveling front solutions and show the existence of a bifurcation to locked fronts where both components invade at the same speed. Expansions of the wave speed as a function of the diffusion constant of one species are obtained. The bifurcation can be sub or super-critical depending on whether the locked fronts exist for parameter values above or below the bifurcation value. Interestingly, in the sub-critical case numerical simulations reveal that the spreading speed of the PDE system does not depend continuously on the coefficient of diffusion.
What do we know about strategies to manage dementia‐related wandering? A scoping review
Authors: Neubauer Noelannah A. , Azad‐Khaneghah Peyman , Miguel‐Cruz Antonio , Liu Lili
Published: August 2018

Three of five persons with dementia will wander, raising concern as to how it can be managed effectively. Wander‐management strategies comprise a range of interventions for different environments. Although technological interventions may help in the management of wandering, no review has exhaustively searched what types of high‐ and low‐technological solutions are being used to reduce the risks of wandering. In this article, we perform a review of gray and scholarly literature that examines the range and extent of high‐ and low‐tech strategies used to manage wandering behavior in persons with dementia. We conclude that although effectiveness of 49 interventions and usability of 13 interventions were clinically tested, most were evaluated in institutional or laboratory settings, few addressed ethical issues, and the overall level of scientific evidence from these outcomes was low. Based on this review, we provide guidelines and recommendations for future research in this field.
The next step: a strategic focus on physical activity and sedentary behaviour in Irish mental health care
Authors: Matthews E. , Cowman M. , Denieffe S.
Published: August 2018

People with severe mental illnesses have dramatically reduced life expectancy compared with the general population, which is largely attributed to physical comorbidity. Physical activity and sedentary behaviour interventions offer a safe and viable therapeutic resource for multi-disciplinary mental health care teams. The accumulating evidence supporting the role of these interventions has changed the focus of mental health strategy in some countries, with new developing roles for certain mental health professionals in this field. However, in Ireland the absence of specialised exercise practitioners places a leadership role for mental health nurses in this regard. National mental health strategy in Ireland should prioritise physical activity and sedentary behaviour interventions, make recommendations for the integration of specialised exercise practitioners in all mental health multidisciplinary teams, and recommend the provision of training and awareness for mental health nurses and other multidisciplinary professionals who are already well placed to address this issue.
Sensor and actuator placement trade-offs for a linear model of spatially developing flows
Authors: Oehler Stephan F. , Illingworth Simon J.
Published: August 2018

We consider feedback flow control of the linearised complex Ginzburg–Landau system. The particular focus is on any trade-offs present when placing a single sensor and a single actuator. The work is presented in three parts. First, we consider the estimation problem in which a single sensor is used to estimate the entire flow field (without any control). Second, we consider the full information control problem in which the entire flow field is known, but only a single actuator is available for control. By considering the optimal sensor placement and optimal actuator placement while varying the stability of the system, a fundamental trade-off for both problems is made clear. Third, we consider the overall feedback control problem in which only a single sensor is available for measurement; and only a single actuator is available for control. By varying the stability of the system, similar fundamental trade-offs are made clear. We discuss implications for effective feedback control with a single sensor and a single actuator and compare it to previous placement methods.
Diminished Expectations
Authors: Holland Alisha C.
Published: August 2018

In Latin America, the relationship between income and support for redistribution is weak and variable despite the region's extreme income inequality. This article shows that this condition is rooted in the truncated structure of many Latin American welfare states. Heavy spending on contributory social insurance for formal-sector workers, flat or regressive subsidies, and informal access barriers mean that social spending does far less for the poor in Latin America than it does in advanced industrial economies. Using public opinion data from across Latin America and original survey data from Colombia, the author demonstrates that income is less predictive of attitudes in the countries and social policy areas in which the poor gain less from social expenditures. Social policy exclusion leads the poor to doubt that they will benefit from redistribution, thereby dampening their support for it. The article reverses an assumption in political economy models that welfare exclusion unleashes demands for greater redistribution. Instead, truncation reinforces skepticism about social policy helping the poor. Welfare state reforms to promote social inclusion are essential to strengthen redistributive coalitions.
Dress, gender and the embodiment of age: men and masculinities
Authors: Twigg Julia
Published: August 2018

The study explores the role of clothing in the constitution of embodied masculinity in age, contrasting its results with an earlier study of women. It draws four main conclusions. First that men's responses to dress were marked by continuity both with their younger selves and with mainstream masculinity, of which they still felt themselves to be part. Age was less a point of challenge or change than for many women. Second, men's responses were less affected by cultural codes in relation to age. Dress was not, by and large, seen through the lens of age; and there was not the sense of cultural exile that had marked many of the women's responses. Third, for some older men dress could be part of wider moral engagement, expressive of values linked positively to age, embodying old-fashioned values that endorsed their continuing value as older men. Lastly, dress in age reveals some of the ways in which men retain aspects of earlier gender privilege. The study was based on qualitative interviews with 24 men aged 58–85, selected to display a range in terms of social class, occupation, sexuality, employment and relationship status. It forms part of the wider intellectual movement of cultural gerontology that aims to expand the contexts in which we explore later years; and contributes to a new focus on materiality within sociology.
Response of fusion plasma-facing materials to nanosecond pulses of extreme ultraviolet radiation
Authors: Straus Jaroslav , Kolacek Karel , Schmidt Jiri , Frolov Oleksandr , Vilemova Monika , Matejicek Jiri , Jager Ales , Juha Libor , Toufarova Martina , Choukourov Andrey , Kasuya Koichi
Published: August 2018

The experimental study of damage to tungsten (W), molybdenum (Mo), and silicon carbide (SiC) surfaces induced by focused extreme ultraviolet laser radiation (λ ~ 47 nm/~1.5 ns/21–40 µJ) is presented. It was found that W and Mo behaved similarly: during the first shot, the damaged area is covered by melted and re-solidified material, in which circular holes appear – residua of just opened pores/bubbles, from which pressurized gas/vapors escaped. Next cracks and ruptures appear and the W has a tendency to delaminate its surface layer. Contrary, single-crystalline SiC has negligible porosity and sublimates; therefore, no escape of “pressurized” gas and no accompanying effects take place. Moreover, SiC at sublimating temperature decomposes to elements; therefore, the smooth crater morphology can be related to local laser energy density above ablation threshold. When more shots are accumulated, in all three investigated materials, the crater depth increases non-linearly with number of these shots. The surface morphology was investigated by an atomic force microscope, the surface structure was imaged by a scanning electron microscope (SEM), and the structure below the surface was visualized by SEM directed into a trench that is milled by focused ion beam. Additionally, structural changes in SiC were revealed by Raman spectroscopy.
THE THEORY OF EXPLOITATION AS THE UNEQUAL EXCHANGE OF LABOUR
Authors: Yoshihara Naoki , Veneziani Roberto
Published: August 2018

This paper explores the foundations of the theory of exploitation as the unequal exchange of labour (UEL). The key intuitions behind all of the main approaches to UEL exploitation are explicitly analysed as a series of formal axioms in a general economic environment. Then, a single domain condition calledLabour Exploitationis formulated, which summarizes the foundations of UEL exploitation theory, defines the basic domain of all UEL exploitation forms, and identifies the formal and theoretical framework for the analysis of the appropriate definition of exploitation.
Beyond Structure and Process: The Early Institutionalization of Regulatory Review
Authors: Rudalevige Andrew
Published: August 2018

With regulatory reform again on the presidential agenda, the history of the Office of Information and Regulatory Affairs (OIRA) provides a useful case study of organizational effectiveness. In 1981, President Ronald Reagan charged OIRA with imposing cost-benefit analysis on agency regulations, formalizing a new process of centralized regulatory review. But OIRA’s effectiveness flowed less from a single executive order than from the previous decade of presidential experimentation with regulatory review and Reagan’s continued investment in its institutionalization. This article draws extensively on archival documents to understand how regulatory review established itself as a constant of presidential management through the development of attributes such as staff capacity, organizational complexity, bureaucratic leverage, and reputation. Today’s policymakers should heed broader lessons for enhancing organizational effectiveness: singular structural and procedural changes are necessary, but not sufficient, for achieving reform.
The impact of automated feedback on L2 learners’ written causal explanations
Authors: Saricaoglu Aysel
Published: August 2018

Even though current technologies allow for automated feedback, evaluating content and generating discourse-specific feedback is still a challenge for automated systems, which explains the gap in research investigating the effect of such feedback. This study explores the impact of automated formative feedback on the improvement of English as a second language (ESL) learners’ written causal explanations within two cause-and-effect essays and across pre- and post-tests. Pre- and post-test drafts, feedback reports for first and revised drafts from the automated writing evaluation system, and screen-capturing videos collected from 31 students enrolled in two sections of an advanced-low-level academic writing class were analyzed through descriptive statistics and the Wilcoxon signed-rank test. Findings revealed statistically significant changes in learners’ causal explanations within one cause-and-effect essay while no significant improvement was observed across pre- and post-tests. The findings of this study offer not only insights into how to further improve automated discourse-specific feedback but also pedagogical implications for better learning outcomes.
Effects of Tactical Emergency Casualty Care Training for Law Enforcement Officers
Authors: Rothschild Heidie R. , Mathieson Kathleen
Published: August 2018

Objective

This study evaluated how Tactical Emergency Casualty Care (TECC) training prepared law enforcement officers (LEOs) with the tools necessary to provide immediate, on-scene medical care to successfully stabilize victims of trauma.

Methods

This was a retrospective, de-identified study using a seven-item Fairfax County (Virginia USA) TECC After-Action Questionnaire and Arlington County (Virginia USA) police reports.

Results

Forty-six encounters were collected from 2015 through 2016. Eighty-four percent (n=39) of the encounters were from TECC After-Action Questionnaires and 15% (n=7) were from police reports. The main injuries included 13% (n=6) arterial bleeds, 46% (n=21) mild/moderate bleeds, 37% (n=17) large wounds, 20% (n=9) penetrating chest wounds, and 13% (n=6) open abdominal wounds. One-hundred percent of officers reported success in stabilizing victim injuries. Seventy-four percent of officers (n=26) did not encounter problems caring for a patient while 26% (n=9) encountered a problem. Ninety-seven percent (n=37/38) answeredYes, the training was sufficient, and three percent (n=1) indicated it wasOK.

Conclusion

This is the most comprehensive study of TECC use among LEOs to date that supports the importance of TECC training for all LEOs in prehospital trauma care. Results of this study showed TECC training prepared LEOs with the operational tools necessary to provide immediate, on-scene medical care to successfully stabilize victims of trauma. Continuing to train increasing numbers of LEOs in TECC is key to saving the lives of victims of trauma in the future.

RothschildHR,MathiesonK.Effects of Tactical Emergency Casualty Care training for law enforcement officers.Prehosp Disaster Med.2018;33(5):495–500.
Memory Strategy Training in Older Adults with Subjective Memory Complaints: A Randomized Controlled Trial
Authors: Frankenmolen Nikita L. , Overdorp Eduard J. , Fasotti Luciano , Claassen Jurgen A.H.R. , Kessels Roy P.C. , Oosterman Joukje M.
Published: August 2018

Objectives: Subjective memory complaints (SMC) in older adults are associated with a decline in everyday functioning and an increased risk for future cognitive decline. This study examines the effect of a memory strategy training compared to a control memory training on memory functioning in daily life. Methods: This was a randomized controlled trial with baseline, post-treatment, and 6-month follow-up assessments conducted in 60 older adults (50–87 years) with SMC. Participants were randomly assigned to either seven sessions of memory strategy training or seven sessions of control memory training. Both interventions were given in small groups and included psycho-education. Primary outcome measure was memory functioning in daily life. Objective measures of memory performance and self-reported measures of strategy use were included as secondary outcome measures. Results: Participants in each intervention group reported an improvement in personal memory goals (p<.0005), up to 6 months after training. An interaction effect showed that participants following memory strategy training reported a larger improvement in personal memory goals (p=.002). Both intervention groups improved on two memory tests (p<.001 and p<.01). In the memory strategy training group, an increase in strategy use in daily life was the strongest predictor (p<.05) of improvement in subjective memory functioning. Conclusions: Older adults with subjective memory complaints benefit from memory strategy training, especially in their memory functioning in daily life. (JINS, 2018, 24, 1110–1120)
Sugar-sweetened beverage taxation in 2017: a commentary on the reasons behind their quick spread in the EU compared with the USA
Authors: Hagenaars Luc L , Jeurissen Patrick PT , Klazinga Niek S
Published: August 2018

In the final issue of Public Health Nutrition in 2017, Kathryn Backholer and colleagues provide a clear overview of the spread of taxes on sugar-sweetened beverages (SSB) in 2017, and a useful overview of opposing arguments and their counterpoints. Backholer et al. argue that much of the action was concentrated in the USA, but in the present commentary we point out that the recent sweep of SSB tax policy announcements in the EU seems much more promising. Policy makers in EU countries seem to learn from neighbouring countries, while political ideologies do not appear to stand in the way. This could have international spillover effects as the default tax thresholds of 5 and 8 g sugar/100 ml, used in EU cases, provide clear incentives for the multinational soda industry to reduce sugar levels across the board, although it is not yet clear whether the tiered tax designs used in the EU are actually more effective than the flat rate tax designs used in the USA. Scholars may contribute to the policy momentum by comparing the effectiveness and feasibility of both designs in different policy contexts, including lower- and middle-income countries. The spread of SSB taxes in the USA will nevertheless most likely be limited so long as it remains a local policy and ‘no-go’ for the Republican Party. We explain the differences between the EU and USA by comparing the level of fiscal decentralization, the political context and the use of framing strategies.
Subclinical thiamine deficiency identified by preoperative evaluation in an ovarian cancer patient: Diagnosis and the need for preoperative thiamine measurement
Authors: Onishi Hideki , Ishida Mayumi , Uchida Nozomu , Shintani Daisuke , Nishikawa Tadaaki , Hasegawa Kosei , Fujiwara Keiichi , Akechi Tatsuo
Published: August 2018

Objective

Although thiamine deficiency (TD) and Wernicke encephalopathy (WE) are not rare in cancer patients, the cases reported to date developed TD and/or WE after treatment had started.

Method

From a series of cancer patients, we report a patient diagnosed with TD without the typical clinical symptoms of WE at the preoperative psychiatric examination.

Result

A 43-year-old woman with ovarian cancer was referred by her oncologist to the psycho-oncology outpatient clinic for preoperative psychiatric evaluation. Her tumor had been growing rapidly before the referral. Although she did not develop delirium, cerebellar signs, or eye symptoms, we suspected she might have developed TD because of her 2-month loss of appetite as the storage capacity of thiamine in the body is approximately 18 days. The diagnosis of TD was supported by abnormally low serum thiamine levels.

Significance of results

Cancer therapists need to be aware that thiamine deficiency may occur even before the start of cancer treatment. In cases with a loss of appetite of more than 2 weeks’ duration, in particular, thiamine deficiency should be considered if the tumor is rapidly increasing, regardless of the presence or absence of delirium.
Evaluation of Freshwater Flow From Rivers to the Sea in CMIP5 Simulations: Insights From the Congo River Basin
Authors: Santini Monia , Caporaso Luca
Published: August 2018

Despite the multisectoral importance of water resources in the context of climate change, it remains still difficult to correctly simulate the terrestrial water cycle via general circulation and Earth system models. While existing model evaluation efforts from the Climate Model Intercomparison Project 5 (CMIP5) are mainly focused on atmospheric variables, we considered here the simulated freshwater flux into the ocean for the river Congo by 20 CMIP5 models. We found that many advancements are still required in global modeling to satisfactorily reproduce the discharge, at least for Congo River. Only the distribution of intermonthly and interannual anomalies of simulated flow, calculated as percent deviations from the respective long‐term average, appears not significantly different from that found in observations. Conversely, most of the models appear to largely overestimate the streamflow seasonal cycle, up to 4–5 times for some months. Further, when looking at severer anomalies in terms of abnormal low‐flow periods (hydrological droughts), the models seem to underestimate their frequency and magnitude while overestimating the duration of deficit conditions with respect to hypothetical water demand. These overall discrepancies between models and observations could propagate in reproducing the land‐ocean feedbacks, as discharge is known to affect sea surface salinity and temperature and, thus, the regional to global ocean circulation and climate. Moreover, biased model‐based discharge simulations could wrongly support water management and infrastructure planning for large river basins, especially when using models instead of measurements, as in case of ungauged rivers, or however when clarification of models' uncertainty is missed.
Late Holocene Structural Style and Seismicity of Highly Transpressional Faults in Southern Haiti
Authors: Wang Jiannan , Mann Paul , Stewart Robert R.
Published: August 2018

The devastating 2010 Haiti earthquake (Mw 7.0) was caused by rupture of the Léogâne, blind, thrust fault located 5 km north of the 1,200‐km‐long, left‐lateral, Enriquillo‐Plantain Garden fault zone (EPGFZ). Unexpectedly, the EPGFZ remained largely quiescent or slightly reactivated during the 2010 earthquake. Nevertheless, the EPGFZ still formed a major, crustal boundary between a coseismically uplifted lowland north of the EPGFZ and a subsided area in the highlands south of the fault. Here we use high‐resolution sonar data from two Haitian Lakes that straddle the EPGFZ to demonstrate the presence of a 10‐ to 15‐km‐wide, 120‐km‐long, late Holocene fold‐thrust belt which deforms clastic, lowland basins along the northern edge of the EPGFZ. In the eastern part of the study area, sonar results from Lake Azuey show that the linear trace of the EPGFZ cutting the Holocene lake bed is more deeply buried and less active than the adjacent, newly discovered, northwest striking, northeast dipping Jimani thrust fault that is part of the adjacent, transpressional belt of en echelon thrusts and folds. This structural relationship between a less active EPGFZ and more recently active, transpression‐related Jimani thrust is remarkably similar to the 2010 epicentral area 70 km to the west between the less active EPGFZ and seismogenic, northeast‐dipping, Léogâne thrust during the 2010 Haiti earthquake. In this complex transpressional zone, we propose that coseismic deformation alternates at recurrence intervals of centuries between oblique, transpression‐related structures (Léogâne, Jimani, and Trois Baies thrusts) and the main strike‐slip, plate boundary fault zone (EPGFZ).
The Ames Stereo Pipeline: NASA's Open Source Software for Deriving and Processing Terrain Data
Authors: Beyer Ross A. , Alexandrov Oleg , McMichael Scott
Published: August 2018

The NASA Ames Stereo Pipeline is a suite of free and open source automated geodesy and stereogrammetry tools designed for processing stereo images captured from satellites (around Earth and other planets), robotic rovers, aerial cameras, and historical images, with and without accurate camera pose information. It produces cartographic products, including digital terrain models, ortho‐projected images, 3‐D models, and bundle‐adjusted networks of cameras. Ames Stereo Pipeline's data products are suitable for science analysis, mission planning, and public outreach.
Experimental Investigation of the Pressure of Crystallization of Ca(OH)2: Implications for the Reactive Cracking Process
Authors: Lambart S. , Savage H. M. , Robinson B. G. , Kelemen P. B.
Published: August 2018

Mineral hydration and carbonation can produce large solid volume increases, deviatoric stress, and fracture, which in turn can maintain or enhance permeability and reactive surface area. Despite the potential importance of this process, our basic physical understanding of the conditions under which a given reaction will drive fracture (if at all) is relatively limited. Our hydration experiments on CaO under uniaxial loads of 0.1 to 27 MPa show that strain and strain rate are proportional to the square root of time and exhibit negative, power law dependence on uniaxial load, suggesting that (1) fluid transport via capillary flow is rate limiting and (2) decreasing strain rate with increasing confining pressure might be a limiting factor in reaction driven cracking at depth. However, our experiments also demonstrate that crystallization pressure due to hydration exceeds 27 MPa (consistent with a maximum crystallization pressure of 153 MPa for the same reaction, Wolterbeek et al., https://doi.org/10.1007/s11440‐017‐0533‐5). As a result, full hydration can be achieved at crustal depths exceeding 1 km, which is relevant for engineered fracture systems.
Optimization of a Laser Ablation‐Single Collector‐Inductively Coupled Plasma‐Mass Spectrometer (Thermo Element 2) for Accurate, Precise, and Efficient Zircon U‐Th‐Pb Geochronology
Authors: Pullen Alex , Ibáñez‐Mejia Mauricio , Gehrels George E. , Giesler Dominique , Pecha Mark
Published: August 2018

Many applications specific to detrital mineral U‐Th‐Pb geochronology in the Earth sciences necessitate large numbers of age observations to be made from samples and require accurate and precise isotope measurements across wide dynamic ranges in elemental concentrations and signal intensities. This implies that the laser system and mass spectrometer cannot be tuned between individual analyses as to optimize measurements based on the isotope composition and concentrations of samples and that intensity matching between the unknowns to be dated and the reference material(s) used for fractionation correction is impossible to ensure. We describe methodologies for optimization of laser ablation‐single collector‐inductively coupled plasma‐mass spectrometer for the accurate determination of initial‐Pb‐corrected (using measured 204Pb) U‐Th‐Pb zircon ages, taking full advantage of the high sensitivity provided by the Thermo Element 2 ICP‐MS instruments fitted with a high‐performance low ultimate vacuum Jet interface. “We describe an approach that corrects for nonlinearity of the detector—the primary obstacle avoided with sample‐specific tuning—as well as element‐ and mass‐dependent fractionation and instrumental drift by using a suite of three zircon reference materials with known isotopic ratios from isotope dilution‐thermal ionization mass spectrometry measurements but with differing U and Pb concentrations.” This approach allows for (experimentally) determining an instrumental fractionation versus ion beam intensity curve used for standard‐sample bracketing, thus taking into consideration an important instrumental variable that is commonly ignored in most applications of U‐Pb dating using laser ablation‐single collector‐inductively coupled plasma‐mass spectrometer. We show that these methodologies yield uncertainties and age offsets typically better than ±2.0% for individual measurements of small (e.g., 10‐μm depth × 20‐μm diameter) volumes of material.
Enhanced Airglow Signature Observed at Titan in Response to its Fluctuating Magnetospheric Environment
Authors: Royer E. M. , Esposito L. W. , Crary F. , Wahlund J.‐E.
Published: August 2018

On rare occasions Titan has been observed in the magnetosheath, where the solar wind interferes with the regular magnetic field generated by Saturn. This particular orbital position allows for a deeper investigation of Titan's upper atmosphere response to its highly energetic magnetospheric environment. Although solar extreme ultraviolet radiation is known to be the main source of ionization in Titan's upper atmosphere, magnetospheric particle precipitation can also account for about 10% of the ionization process. We are reporting here on ultraviolet observations of Titan airglow enhancements occurring while the spacecraft and Titan are known to have been exposed to the magnetosheath environment. Using remote sensing Cassini Ultraviolet Imaging Spectrograph observations of Titan in correlation with in situ Cassini Plasma Spectrometer measurements, we present evidence of Titan's upper atmosphere response to an electron burst crossing the magnetosheath at the time of the T32 flyby, on 13 June 2007.
Partitioning Evapotranspiration Over the Continental United States Using Weather Station Data
Authors: Rigden Angela J. , Salvucci Guido D. , Entekhabi Dara , Short Gianotti Daniel J.
Published: August 2018

Accurately characterizing evapotranspiration is critical when predicting the response of the hydrologic cycle to climate change. Although Earth system models estimate similar magnitudes of global evapotranspiration, the magnitude of each contributing source varies considerably between models due to the lack of evapotranspiration partitioning data. Here we develop an observation‐based method to partition evapotranspiration into soil evaporation and transpiration using meteorological data and satellite soil moisture retrievals. We apply the methodology at 1,614 weather stations across the continental United States during the summers of 2015 and 2016. We evaluate the method using vegetation indices inferred from satellites, finding strong spatial correlations between modeled transpiration and solar‐induced fluorescence (r2 = 0.87), and modeled vegetation fraction and leaf area index (r2 = 0.70). Since the sensitivity of evapotranspiration to environmental factors depends on the contribution of each source component, understanding the partitioning of evapotranspiration is increasingly important with climate change.
Retreat of the Western Cordilleran Ice Sheet Margin During the Last Deglaciation
Authors: Darvill C. M. , Menounos B. , Goehring B. M. , Lian O. B. , Caffee M. W.
Published: August 2018

The timing of Cordilleran Ice Sheet deglaciation along the central coast of British Columbia, Canada, informs climate forcing and early human migration. Thirty‐two 10Be exposure ages from glacial erratics and local bedrock on the western margin of the former ice sheet represent the earliest exposure ages for the Cordilleran Ice Sheet during the last deglaciation. These data show the western ice margin was retreating by 18.1 ± 0.2 ka, consistent with the global record of ice mass loss. In contrast, parts of the southern margin reached a maximum at ca. 17.6–16.6 ka, and our data demonstrate a diachronous response of the Cordilleran Ice Sheet during deglaciation. We also show that a low altitude site was exposed by at least 17.7 ± 0.3 ka, implying that numerous ice‐free areas existed along the coastal margin by this time, providing a viable route for the first humans entering the Americas.
Variations of Earth Magnetic Field Intensity for the Past 5 Myr Derived From Marine Magnetic Anomalies in a Slow‐to‐Intermediate Spreading South Atlantic Ridge
Authors: Li Yuanjie , Liu QingSong , Wei Dongping , Li Sanzhong , Yu Yongjae
Published: August 2018

We investigated sea‐surface magnetic anomaly data for the past 5 Myr in the slow‐to‐intermediate spreading South Atlantic Ridge. After error analysis and signal processes, the sea surface magnetic anomaly profiles were downward continued to 1.5 km below sea level, and then the distance from spreading axis was converted to time by matching the observed anomalies with forward models of known polarity reversals. The stacked anomaly profiles from South Atlantic Ridge exhibit short‐wavelength wiggles superimposed on the first‐order variations of magnetic anomalies. The stacked anomaly profiles were first compared with commonly used geomagnetic palaeointensity data synthesized from sedimentary relative intensity records in the past and were further correlated with other available magnetic profiles derived from Central Indian Ridge, East Pacific Rise, and Pacific‐Antarctic Ridge. We found that short wavelength variations in the South Atlantic Ridge can be ascribed to geomagnetic intensity variations from excursions or short polarity events. Spectral analysis of marine magnetic anomalies records reveals that there is no obvious dominant periodicity for the geomagnetic field behavior during the past 5 Myr.
Reconstructed Precipitation Tritium Leads to Overestimated Groundwater Recharge
Authors: Li Zhi , Si Bingcheng
Published: August 2018

Time series of precipitation tritium contents are often used for groundwater recharge estimation based on the tritium mass ratio of the (un) saturated zones to precipitation. But records of the precipitation tritium measurements are sparse and often need to be reconstructed. Uncertainties associated with reconstructed records can affect the recharge estimates, but this has received little attention. Here we leverage four >15 m deep, exceptionally well preserved unsaturated zone tritium profiles to quantify the uncertainty in Tritium mass balance from precipitation tritium reconstruction. The tritium profiles have bomb tritium peaks at 7.2–10.5 m below the surface and peaks ranging from 46 to 235 tritium unit. We first estimate the diffuse recharge by the tritium peak method. Since this method is independent of any precipitation tritium reconstruction, the estimated recharge was used as truth to evaluate four precipitation tritium reconstruction methods: two interpolation methods and two reference curve methods. Direct comparison between the observed and simulated precipitation tritium showed that the reference curve methods performed more poorly than the interpolation methods. Indirect evaluation by comparing the recharge rates estimated by the tritium storage method with our truth measurements showed that tritium storage method overestimated recharge by 100% to 200%. Our results suggest that the atmospheric tritium flux was greatly underestimated, especially by the reference curve methods. As such, groundwater recharge at our sites would be overestimated. This has implications for using these standard approaches elsewhere.
Hurricane Warm‐Core Retrievals from AMSU‐A and Remapped ATMS Measurements with Rain Contamination Eliminated
Authors: Zou Xiaolei , Tian Xiaoxu
Published: August 2018

Due to a shorter effective integration time for each field of view of the Advanced Microwave Temperature Sounder (ATMS) onboard the Suomi National Polar‐orbiting Partnership (S‐NPP) satellite than that for the Advanced Microwave Sounding Unit‐A (AMSU‐A) onboard previous National Oceanic and Atmospheric Administration (NOAA) polar‐orbiting satellites NOAA‐15 to NOAA‐19, ATMS temperature‐sounding channels have higher observational resolutions and larger noise equivalent differential temperatures than the corresponding AMSU‐A channels. The high resolution of the ATMS allows hurricane rainband features that are not resolvable by AMSU‐A to be captured. But the larger noise equivalent differential temperature of ATMS weakens this capability through the significant impact of observational noise on warm‐core retrievals. In this study, a remapping algorithm is applied to obtain AMSU‐A‐like ATMS fields of view to suppress this noise. A modified warm‐core retrieval algorithm, which consists of two sets of training coefficients for clear‐sky and cloudy conditions, is applied to limb‐corrected ATMS and AMSU‐A measurements using collocated Global Positioning System radio occultation observations in the previous month of the targeted hurricanes as training data sets. ATMS channels 5, 6, and 7 (AMSU‐A channels 4, 5, and 6) are excluded when training the coefficients for cloudy conditions to avoid cloud/rain contamination. As a result, the abnormal cold core in the low and middle troposphere and the banded warm structures in phase with rainbands are both successfully removed. The warm‐core evolution of Hurricane Matthew (2016) during its entire life span is temporally consistent on intensity as obtained from NOAA‐15, NOAA‐18, and MetOp‐B AMSU‐A observations and S‐NPP ATMS observations.
Wildfire Smoke Cools Summer River and Stream Water Temperatures
Authors: David Aaron T. , Asarian J. Eli , Lake Frank K.
Published: August 2018

To test the hypothesis that wildfire smoke can cool summer river and stream water temperatures by attenuating solar radiation and air temperature, we analyzed data on summer wildfire smoke, solar radiation, air temperatures, precipitation, river discharge, and water temperatures in the lower Klamath River Basin in Northern California. Previous studies have focused on the effect of combustion heat on water temperatures during fires and the effect of riparian vegetation losses on postfire water temperatures, but we know of no studies of the effects of wildfire smoke on river or stream water temperatures. Wildfire smoke is difficult to quantify, but we successfully used a newly available daily high‐resolution (1 km) data set of aerosol optical thickness (AOT) derived from satellite imagery to represent smoke density during 6 years with extensive wildfire activity (2006, 2008, and 2012–2015). Smoke reduced solar radiation by 121 W m−2 per 1.0 AOT relative to clear‐sky conditions. Linear mixed‐effects models showed that on average, smoke cooled daily maximum and mean air temperatures by 0.98 °C and 0.47 °C per 1.0 AOT, respectively, across 19 remote automated weather stations. Smoke had a cooling effect on water temperatures at all 12 river and stream locations analyzed. On average, smoke cooled daily maximum and mean water temperatures by 1.32 °C and 0.74 °C per 1.0 AOT, respectively. This smoke‐induced cooling has the potential to benefit cold‐water adapted species, particularly because wildfires are more likely to occur during the warmest and driest years and seasons.