bluuebunny/crossref_metadata_2025 huggingface dataset:
A weighted rebinned backprojection‐filtration algorithm from partially beam‐blocked data for a single‐scan cone‐beam CT with hybrid type scatter correction
Authors: Min Jonghwan , Pua Rizza , Kim Changhwan , Park Miran , Lee Jongha , Ye Sung‐Joon , Cho Seungryong
Published: December 2018

Purpose

Scatter contamination constitutes a dominant source of degradation of image quality in cone‐beam computed tomography (CBCT). We have recently developed an analytic image reconstruction method with a scatter correction capability from the partially blocked cone‐beam data out of a single scan. Despite its easy implementation and its computational efficiency, the developed method may result in additional image artifacts for a large cone angle geometry due to data inconsistency. To improve the image quality at a large cone angle, we propose a weighted rebinned backprojection‐filtration (wrBPF) algorithm in conjunction with a hybrid type scatter correction approach.

Methods

The proposed method uses a beam‐blocker array that provides partial data for scatter correction and image reconstruction and that only blocks the beam within a limited cone angle. This design allows a chance to keep the image quality at larger cone angles by use of data redundancy since the projection data corresponding to larger cone angles are not blocked. However, the scatter correction would not be straightforward. In order to correct for the scatter in the projections at larger cone angles, we propose a novel scatter correction method combining a measurement‐based and a convolution‐based method. We first estimated the scatter signal using a measurement‐based method in the partially beam‐blocked regions, and then optimized the fitting parameters of a convolution‐kernel that can be used for scatter correction in the projections at larger cone angles. For image reconstruction, we developed a wrBPF with butterfly filtering. We have conducted an experimental study to validate the proposed algorithm for image reconstruction and scatter correction.

Results

The experimental results revealed that the developed reconstruction method makes full use of the benefits of partial beam‐blocking for scatter correction and image reconstruction and at the same time enhances image quality at larger cone angles by use of an optimized convolution‐based scatter correction.

Conclusions

The proposed method that enjoys the advantages of both measurement‐based and convolution‐based methods for scatter correction has successfully demonstrated its capability of reconstructing accurate images out of a single scan in circular CBCT.
GAG replenishment therapy for bladder pain syndrome/interstitial cystitis
Authors: Wyndaele Jean Jacques J , Riedl Claus , Taneja Rajesh , Lovász Sándor , Ueda Tomohiro , Cervigni Mauro
Published: December 2018

Aims

To present a rationale for the inclusion of urothelial coating dysfunction in the etipathogenesis of bladder pain syndrome/interstitial cystitis (BPS/IC) and the preclinical and clinical evidence in support of glycosaminoglycan (GAG) replenishment therapy in the treatment of BPS/IC, supplemented by the clinical experience of medical experts in the field and patient advocates attending a symposium on GAG replenishment at ESSIC’17, the annual Meeting of the International Society for the Study of Bladder Pain Syndrome, held in Budapest, Hungary in 2017.

Results

The urothelial GAG layer has a primary role in providing a permeability barrier to prevent penetration of urinary toxins and pathogens into the bladder wall. Disruption of the GAG layer contributes to the development of BPS/IC. The evidence shows that replenishment of GAGs can restore the GAG layer in BPS/IC, reducing inflammation, pain, and other symptoms.

Conclusions

Although data from large randomized controlled studies are limited, long clinical observation and the experience of clinicians and patients support the beneficial effects of intravesical GAG replenishment therapy for providing symptomatic relief for patients with BPS/IC.
Posterior reversible encephalopathy syndrome in children with acute lymphoblastic leukemia: Clinical characteristics, risk factors, course, and outcome of disease
Authors: Anastasopoulou Stavroula , Eriksson Mats A. , Heyman Mats , Wang Chen , Niinimäki Riitta , Mikkel Sirje , Vaitkevičienė Goda E. , Johannsdottir Inga Maria , Myrberg Ida Hed , Jonsson Olafur Gisli , Als‐Nielsen Bodil , Schmiegelow Kjeld , Banerjee Joanna , Harila‐Saari Arja , Ranta Susanna
Published: December 2018

Background

Posterior reversible encephalopathy syndrome (PRES) is a distinct entity with incompletely known predisposing factors. The aim of this study is to describe the incidence, risk factors, clinical course, and outcome of PRES in childhood acute lymphoblastic leukemia (ALL).

Procedure

Patients aged 1.0 to 17.9 years diagnosed with ALL from July 2008 to December 2015 and treated according to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) ALL2008 protocol were included. Patients with PRES were identified in the prospective NOPHO leukemia toxicity registry, and clinical data were collected from the medical records.

Results

The study group included 1378 patients, of whom 52 met the criteria for PRES. The cumulative incidence of PRES at one month was 1.7% (95% CI, 1.1–2.5) and at one year 3.7% (95% CI, 2.9–4.9). Older age (hazard ratios [HR] for each one‐year increase in age 1.1; 95% CI, 1.0–1.2, P = 0.001) and T‐cell immunophenotype (HR, 2.9; 95% CI, 1.6–5.3, P = 0.0005) were associated with PRES. Central nervous system (CNS) involvement (odds ratios [OR] = 2.8; 95% CI, 1.2–6.5, P = 0.015) was associated with early PRES and high‐risk block treatment (HR = 2.63; 95% CI, 1.1–6.4, P = 0.033) with late PRES. At follow‐up of the PRES patients, seven patients had epilepsy and seven had neurocognitive difficulties.

Conclusion

PRES is a neurotoxicity in the treatment of childhood ALL with both acute and long‐term morbidity. Older age, T‐cell leukemia, CNS involvement and high‐risk block treatment are risk factors for PRES.
Influence of POSS fillers on the transport properties of natural rubber nanocomposites
Authors: Lakshmipriya S. , Anil Kumar S. , Nandakumar K. , Thomas Sabu
Published: December 2018

Three types of polyhedral oligomeric silsesquioxane (POSS)—octaphenyl (OP), POSS@TESPT (TT), and MWCNT@POSS (VC)—were incorporated into natural rubber (NR) to fabricate nanocomposites. The transport properties of POSS–NR nanocomposites were studied through solvent diffusion techniques. Diffusion studies were done with toluene (aromatic solvent) and the influence of nanofiller structure, concentration and compatibility with the NR matrix on various diffusion parameters were analyzed. The fillers that have good interaction with the polymer matrix showed the lowest solvent uptake. The network structure analysis revealed that the polymer chains deformed affinely. The effect of fillers on the chain flexibility was also discussed based on mechanical property studies. POLYM. COMPOS., 40:3020–3031, 2019. © 2018 Society of Plastics Engineers
Mechanical properties of carbon nanotube‐filled polyethylene composites: A molecular dynamics simulation study
Authors: Yazdani Hessam , Ghasemi Hamid , Wallace Camille , Hatami Kianoosh
Published: December 2018

Molecular dynamics (MDs) simulations are carried out to study the mechanical properties of low‐ and high‐density polyethylene (LDPE and HDPE) and their composites filled with carbon nanotubes (CNTs). The influences of the number of polymer chains, CNT type and concentration, and strain rate on the predicted mechanical properties are studied. Two different temperatures of 100 and 300 K are used to represent the glassy and rubbery states of the polymers, respectively. Results indicate that the models typically show four stages of deformation before failure: linear elastic and yield followed by strain softening and strain hardening. Thepristine models simulated at a given temperature exhibit a similar behavior regardless of their density, especially during the linear elastic stage. The HDPE models exhibit fairly similar behaviors in their strain‐hardening response regardless of the number of chains, while this factor considerably influences the strain‐hardening response of the LDPE models. Strain rate is shown to have a strong influence on different mechanical characteristics of all of polymer models examined (i.e., elastic modulus, yield stress, post‐yield strain softening, and strain hardening behavior). In contrast, LDPE and HDPE composites exhibit essentially the same behavior and similar failure characteristics under a given temperature regardless of the strain rate applied. The tensile strength of CNT‐filled LDPE and HDPE increases linearly with CNT concentration within the range of concentrations studied (0.79–2.63 wt%) and is inversely proportional to the CNT chirality. The results are thoroughly discussed and the factors contributing to their departure from reference laboratory data are outlined. POLYM. COMPOS., 40:E1850–E1861, 2019. © 2018 Society of Plastics Engineers
Evaluation of Prophylactic Heparin Dosage Strategies and Risk Factors for Venous Thromboembolism in the Critically Ill Patient
Authors: Reynolds Paul M. , Van Matre Edward T. , Wright Garth C. , McQueen Robert Brett , Burnham Ellen L. , Ho Pei Jai Michael , Moss Marc , Vandivier Robert William , Kiser Tyree H. ,   Colorado Pulmonary Outcomes Research Group (CPOR)
Published: December 2018

Background

Venous thromboembolism (VTE) occurs frequently in critically ill patients without heparin prophylaxis. Although heparin prevents VTE, VTEs occur frequently despite prophylaxis. A higher heparin dosage may be more effective for preventing VTE.

Methods

A retrospective study was conducted using the Premier Incorporated Perspective Database to evaluate comparatively the effects of different heparin prophylaxis dosing strategies in the critically ill patient. Critically ill adult patients who were mechanically ventilated for at least 1 day and had an intensive care unit (ICU) length of stay of at least 2 days were included. Patients received 5000 units of heparin either twice/day or 3 times/day. The primary outcome was development of a new VTE. Key secondary outcomes included clinically important bleeding, thrombocytopenia, and mortality. Patients were propensity matched to control for confounding. Multivariable analysis was conducted for VTE risk factors.

Results

The study included 30,800 patients from 374 hospitals who were propensity matched by heparin dosage. New VTE occurred in 6.16% of patients treated with 3 times/day heparin versus 6.23% with twice/day heparin (p=0.8). No significant differences in the incidence of pulmonary embolism (0.91% vs 0.8%, p=0.29) or deep vein thrombosis (5.56% vs 5.70% p=0.59) were observed between the two types of heparin dosing. No differences were observed between the two types of heparin dosing in in‐hospital mortality (15.8% vs 15.15%), bleeding (0.23% vs 0.33%), or thrombocytopenia (5.19% vs 5.34%, p>0.08 for all), respectively. Risk factors associated with VTE included intraabdominal and urinary tract infections, loop diuretics, malnutrition, obesity, thrombocytopenia, paralytics, vasopressors, female sex, peripheral vascular disease, sepsis, neutropenia, and end‐stage renal disease. Antiplatelet therapy, heart failure, diabetes, and substance abuse were associated with reduced VTE (p<0.05 for all).

Conclusions

In critically ill patients, prophylactic dosing of heparin 3 times/day versus twice/day was not associated with differences in new VTE or safety outcomes. Several modifiable VTE risk factors were identified.
The concurrent validity of a Web‐based self‐report assessment for personality disorders
Authors: Chakhssi Farid , Dijksman Ies , Velmans Mara L. , Zoet J. Monique , Oostendorp Jeanine M. , Dinant Geert‐Jan , Spigt Mark
Published: December 2018

Incorporating online tools in clinical practice could help improve routine assessments of personality disorders and their co‐occurring clinical disorders. TeleScreen, a Web‐based self‐report questionnaire for DSM‐IV disorders, has not yet been compared with well‐validated structured interviews for clinical and personality disorders. Patients with personality disorders (n = 89) were assessed with TeleScreen and independently interviewed with Structured Clinical Interview for DSM‐IV Axis‐I disorders (SCID‐I) and personality disorders (SCID‐II). The concurrent validity was examined using sensitivity, specificity, and positive and negative predictive values. Five personality disorders had a prevalence rate higher than 4% and could be examined in the analyses: borderline, obsessive–compulsive, dependent, avoidant and paranoid personality disorders. TeleScreen showed moderate to good validity for borderline personality disorder and obsessive–compulsive personality disorder but suboptimal validity for the dependent, avoidant and paranoid personality disorders. Clinical disorders showed moderate to good values, except for social phobia, dysthymia and eating disorders. These findings provide preliminary evidence for the concurrent validity of TeleScreen for some personality disorders, such as the borderline personality disorder, and pave the way for larger studies to confirm these results. © 2018 John Wiley & Sons, Ltd.
Formation and Characterization of Shallow Junctions in GaAs Made by Ion Implantation and ms‐Range Flash Lamp Annealing
Authors: Duan Juanmei , Wang Mao , Vines Lasse , Böttger Roman , Helm Manfred , Zeng Yu‐Jia , Zhou Shengqiang , Prucnal Slawomir
Published: December 2018

With the demand of aggressive scaling in nanoelectronics, further progress can be realized by integration of high mobility semiconductors, such as III–V compound semiconductors, with complementary metal‐oxide‐semiconductor (CMOS) technology. In this study, the formation of shallow n–p and p–n junctions in GaAs utilizing ion implantation of S and Zn, respectively, followed by millisecond‐range flash lamp annealing (FLA) is presented. The distribution of implanted elements obtained by secondary ion mass spectrometry (SIMS) shows that the FLA process can effectively suppress the diffusion of dopants. Simultaneously, the ms‐range annealing is sufficient to recrystallize the implanted layer and to activate the dopants. Formation of p–n and n–p junctions is confirmed by current–voltage characteristics. The ratio of reverse to forward current can reach up to 1.7 × 107 in the n‐GaAs:Zn case.
Local open‐ and closed‐loop manipulation of multiagent networks
Authors: Sahabandu Dinuka , Abad Torres Jackeline , Dhal Rahul , Roy Sandip
Published: December 2018

The manipulation of networked cyberphysical devices via local external actuation or feedback control is explored, in the context of a canonical multiagent dynamical system that is engaged in a consensus or synchronization task. One main focus is to understand whether or not, and how easily, a stakeholder can manipulate the full network's dynamics by hijacking only one agent's actuation signal. Explicit spectral characterizations are given of the energy (effort) required to manipulate the dynamics. These characterizations are used to (1) gain structural insights into ease of manipulation, (2) show that manipulation along the consensus manifold is easy, and (3) address network design to enable or prevent manipulation. Additionally, it is shown that the multiagent system can be manipulated effectively along the consensus manifold using local feedback controls, which do not require model knowledge or wide‐area measurements.
Observer‐based adaptive control for nonlinear strict‐feedback stochastic systems with output constraints
Authors: Xu Yuanyuan , Liang Hongjing , Li Tieshan , Ma Hui
Published: December 2018

In this paper, an adaptive output‐feedback control problem is investigated for nonlinear strict‐feedback stochastic systems with input saturation and output constraint. A barrier Lyapunov function is used to solve the problem of output constraint. Then, fuzzy logic systems are used to approximate the unknown nonlinear functions, and a fuzzy state observer is designed to estimate the unmeasured states. To overcome the difficulties in designing the control signal in the saturation, we introduce an auxiliary signal in the n + 1th step in the deduction. By combining Nussbaum technique and the adaptive backstepping technique, an adaptive output‐feedback control method is developed. The proposed control method not only overcomes the problem of the compensation for the nonlinear term from the input saturation but also overcomes the problem of unavailable state measurements. It is proved that all the signals of the closed‐loop system are semiglobally uniformly ultimately bounded. Finally, the effectiveness of the proposed method is verified by the simulation results.
Umbilical Cord-Derived Mesenchymal Stromal Cells (MSCs) for Knee Osteoarthritis: Repeated MSC Dosing Is Superior to a Single MSC Dose and to Hyaluronic Acid in a Controlled Randomized Phase I/II Trial
Authors: Matas Jose , Orrego Mario , Amenabar Diego , Infante Catalina , Tapia-Limonchi Rafael , Cadiz Maria Ignacia , Alcayaga-Miranda Francisca , González Paz L. , Muse Emilio , Khoury Maroun , Figueroa Fernando E. , Espinoza Francisco
Published: December 2018

Knee osteoarthritis (OA) is a leading cause of pain and disability. Although conventional treatments show modest benefits, pilot and phase I/II trials with bone marrow (BM) and adipose-derived (AD) mesenchymal stromal cells (MSCs) point to the feasibility, safety, and occurrence of clinical and structural improvement in focal or diffuse disease. This study aimed to assess the safety and efficacy of the intra-articular injection of single or repeated umbilical cord-derived (UC) MSCs in knee OA. UC-MSCs were cultured in an International Organization for Standardization 9001:2015 certified Good Manufacturing Practice-type Laboratory. Patients with symptomatic knee OA were randomized to receive hyaluronic acid at baseline and 6 months (HA, n = 8), single-dose (20 × 106) UC-MSC at baseline (MSC-1, n = 9), or repeated UC-MSC doses at baseline and 6 months (20 × 106 × 2; MSC-2, n = 9). Clinical scores and magnetic resonance images (MRIs) were assessed throughout the 12 months follow-up. No severe adverse events were reported. Only MSC-treated patients experienced significant pain and function improvements from baseline (p = .001). At 12 months, Western Ontario and Mc Master Universities Arthritis Index (WOMAC-A; pain subscale) reached significantly lower levels of pain in the MSC-2-treated group (1.1 ± 1.3) as compared with the HA group (4.3 ± 3.5; p = .04). Pain Visual Analog scale was significantly lower in the MSC-2 group versus the HA group (2.4 ± 2.1 vs. 22.1 ± 9.8, p = .03) at 12 months. For total WOMAC, MSC-2 had lower scores than HA at 12 months (4.2 ± 3.9 vs. 15.2 ± 11, p = .05). No differences in MRI scores were detected. In a phase I/II trial (NCT02580695), repeated UC-MSC treatment is safe and superior to active comparator in knee OA at 1-year follow-up. Stem Cells Translational Medicine  2019;8:215&224
A new long‐term evolution downlink delay based lean scheduler
Authors: Sağlam Mehmet İzzet , Kavas Aktül , Kartal Mesut
Published: December 2018

A new delay‐based long‐term evolution scheduler is proposed in this paper. The scheduler allows sharing of radio and base station resources between different radio bearers. It provides a trade‐off between user fairness and system performance. The proposed algorithm is based on the scheduler having knowledge of the age of real‐time (RT) applications packets. By considering the age of the packet with the lean production concept, the scheduler can determine different types of RT application packets and must be scheduled within their packet delay budget. The proposed algorithm is called the delay‐based lean scheduler (DBLS). Simulation results shows that the proposed DBLS algorithm provides superior throughput and delay performance to the modified largest weighted delay first (M‐LWDF) algorithm irrespective of the number of users. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Capturing Crows for the Protection of Threatened and Endangered Shorebird Species
Authors: Leo Brian T. , Manley Steven J.
Published: December 2018

Corvids are highly intelligent and capable of thriving in anthropogenic ecosystems. American crows (Corvus brachyrhynchos) regularly depredate threatened and endangered avian species. Live capture is a common component of crow management programs; however, crows are notoriously difficult to capture. Here, we report previously undocumented crow capture techniques, utilizing a modified goshawk (Accipiter gentilis) trap design as part of a shorebird conservation project in San Diego, California, USA, 2012–2017. A negative binomial generalized linear model showed a significant relationship between number of crows removed and number of endangered California least tern (Sternula antillarum browni) eggs predated by crows. Of the total number of crows in that analysis, 67% were removed via goshawk trap. Therefore, we attribute the same percentage of reduction in egg loss to the success of that trap type. We tested 2 goshawk trap designs that differed by number of capture chambers (single and double). Double‐chambered traps were nearly twice as effective at capturing crows compared with single‐chambered traps. We performed McNemar's χ2 tests with continuity correction to determine whether traps were more effective with the use of conspecific lure‐birds and obtained significant results for single and double‐chambered traps. The modified goshawk trap has an efficient design that can improve crow control programs, especially when constructed with 2 chambers and deployed with lure‐birds. © 2018 The Wildlife Society.
Fairness, Compulsory Vaccination, and Conscientious Objection
Authors: Giubilini Alberto
Published: December 2018

This chapter presents an argument for compulsory vaccination and against allowing non-medical vaccine exemptions. The argument is based on the idea that the proper aim of vaccination policies should be not only herd immunity but also a fair distribution of the burdens entailed by its realization. I argue that a fairness requirement need not and should not be constrained by a principle of liberty and a principle of least restrictive alternative. Indeed, I argue how compulsory vaccination is more successful than other types of vaccination policies at satisfying the principles of fairness, least restrictive alternative, and maximizing expected utility, once these principles have been properly understood.
The Business of Surgery
Authors: Frampton Sally
Published: December 2018

This chapter focuses on the financial implications of the operation for both patient and practitioner, paying particular attention to the period between 1870 and 1900 when there was increasing concern about the overuse of ovariotomy. The latter development is often read solely through changing notions of female pathology; this chapter offers a new approach to the period by situating the expansion of the operation primarily within a discourse of trade and business, which nonetheless was often gendered. The powerful financial connotations of ovariotomy were revealing not only of the ascendance of surgeons’ professional status (in which money played an implicit role) but also the pecuniary gains—and losses—that association with surgical innovation could bring.
A phase 1 dose escalation and expansion study of Tarextumab (OMP-59R5) in patients with solid tumors
Authors: Smith David C. , Chugh Rashmi , Patnaik Amita , Papadopoulos Kyriakos P. , Wang Min , Kapoun Ann M. , Xu Lu , Dupont Jakob , Stagg Robert J. , Tolcher Anthony
Published: December 2018

Purpose This Phase I trial evaluated the maximum tolerated dose, safety, pharmacokinetics, pharmacodynamics and preliminary efficacy of tarextumab (OMP-5948), a novel cross-reactive antibody which binds and selectively inhibits signaling via both Notch2 and Notch3, in adult patients with advanced malignancies. Methods Standard 3 + 3 design with tarextumab 0.5, 1, 2.5, or 5 mg/kg weekly, or 5, 7.5, or 10 mg/kg every other week, or 7.5 mg every 3 weeks. Dose-limiting toxicities (DLT) were assessed during the first 28 days. Results Forty-two patients received tarextumab (21 weekly, 15 every other week, 6 every three weeks). 2/6 subjects at the 5 mg/kg weekly dose, 2/3 at 10 mg/kg every other week, and 0/6 at 7.5 mg/kg every three weeks had a DLT. The maximum tolerated dose (MTD) was 2.5 mg/kg weekly, and 7.5 mg/kg on the every other and every three week schedules. Gastrointestinal (GI) toxicity was the most common adverse event with diarrhea (81%), fatigue (48%), nausea (45%), anorexia (38%), and vomiting (38%) and abdominal pain and constipation (24% each). Biomarker analysis showed regulation of stem cell and Notch gene signaling. Conclusion Tarextumab was generally well-tolerated at doses <2.5 mg weekly and 7.5 mg/kg every other and every third week. Diarrhea was dose-limiting above these levels, but relatively easily managed at lower doses. Inhibition of Notch pathway signaling was demonstrated at these doses. ClinicalTrials.gov Identifier: NCT01277146.
Earthquake-Induced Injuries: Retrospective Epidemiological Analysis of the 2015 Hindu Kush Earthquake in Pakistan
Authors: Ahmad Junaid , Ahmad Mokbul Morshed , Rodríguez Elena Espigares
Published: December 2018

Objective

The aim of this study was to analyze retrospectively the earthquake-induced injuries caused by the October 2015 Hindu Kush earthquake in Pakistan. This is the first population-based study to assess epidemiologically earthquake-induced injuries in the Hindu Kush region, one of the world’s most mountainous and seismically active regions. Unfortunately, only limited studies have investigated the earthquake-induced injuries and deaths in the region epidemiologically.

Methods

The 5 worst affected districts were selected according to the highest number of deaths and injuries recorded. A total of 1,790 injuries and 232 deaths were reported after the 2015 earthquake. In our study area, 391 persons were recorded and verified to have been injured as a result of the earthquake. We attempted to investigate all of the 391 injured people, but the final study looked at 346 subjects because the remaining 45 subjects could not be traced because of the non-availability of their complete records and their refusal to participate in the study.

Results

Using the International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD 10), we found that the highest number – 20.23% (70 of 346) – of injuries in the earthquake fall in the class of “Injuries to an unspecified part of trunk, limb, or body region (T08-T14).” The class of “Injuries to knee and lower leg (S80-S89),” which count 15.61% (54 out of 346), followed it, and “Injuries involving multiple body regions (T00-T07)” were making 14.74% of total injuries (51 out of 346).

Conclusion

In times of natural disasters like earthquakes, collecting and analyzing real-time data can be challenging. Therefore, a retrospective data analysis of deaths and injuries induced by the earthquake is of high importance. Studies in these emerging domains will be crucial to initiate health policy debates and to prevent and mitigate future injuries and deaths. (Disaster Med Public Health Preparedness. 2018;13:732–739).
Model parameter estimation using coherent structure colouring
Authors: Schlueter-Kuck Kristy L. , Dabiri John O.
Published: December 2018

Lagrangian data assimilation is a complex problem in oceanic and atmospheric modelling. Tracking drifters in large-scale geophysical flows can involve uncertainty in drifter location, complex inertial effects and other factors which make comparing them to simulated Lagrangian trajectories from numerical models extremely challenging. Temporal and spatial discretisation, factors necessary in modelling large scale flows, also contribute to separation between real and simulated drifter trajectories. The chaotic advection inherent in these turbulent flows tends to separate even closely spaced tracer particles, making error metrics based solely on drifter displacements unsuitable for estimating model parameters. We propose to instead use error in the coherent structure colouring (CSC) field to assess model skill. The CSC field provides a spatial representation of the underlying coherent patterns in the flow, and we show that it is a more robust metric for assessing model accuracy. Through the use of two test cases, one considering spatial uncertainty in particle initialisation, and one examining the influence of stochastic error along a trajectory and temporal discretisation, we show that error in the coherent structure colouring field can be used to accurately determine single or multiple simultaneously unknown model parameters, whereas a conventional error metric based on error in drifter displacement fails. Because the CSC field enhances the difference in error between correct and incorrect model parameters, error minima in model parameter sweeps become more distinct. The effectiveness and robustness of this method for single and multi-parameter estimation in analytical flows suggest that Lagrangian data assimilation for real oceanic and atmospheric models would benefit from a similar approach.
A general fluid–sediment mixture model and constitutive theory validated in many flow regimes
Authors: Baumgarten Aaron S. , Kamrin Ken
Published: December 2018

We present a thermodynamically consistent constitutive model for fluid-saturated sediments, spanning dense to dilute regimes, developed from the basic balance laws for two-phase mixtures. The model can represent various limiting cases, such as pure fluid and dry grains. It is formulated to capture a number of key behaviours such as: (i) viscous inertial rheology of submerged wet grains under steady shearing flows, (ii) the critical state behaviour of grains, which causes granular Reynolds dilation/contraction due to shear, (iii) the change in the effective viscosity of the fluid due to the presence of suspended grains and (iv) the Darcy-like drag interaction observed in both dense and dilute mixtures, which gives rise to complex fluid–grain interactions under dilation and flow. The full constitutive model is combined with the basic equations of motion for each mixture phase and implemented in the material point method (MPM) to accurately model the coupled dynamics of the mixed system. Qualitative results show the breadth of problems which this model can address. Quantitative results demonstrate the accuracy of this model as compared with analytical limits and experimental observations of fluid and grain behaviours in inhomogeneous geometries.
Early Miocene shallow-water corals from La Guajira, Colombia: Part II, Mussidae–Siderastreidae and Milleporidae
Authors: Flórez Paola , Zapata-Ramírez Paula , Klaus James S.
Published: December 2018

In this contribution we describe and illustrate 14 coral morphospecies collected from the early Miocene Siamaná (Aquitanian–Burdigalian) and Jimol (late Burdigalian) formations of the Cocinetas Basin in La Guajira Peninsula, northern Colombia. Eleven were identified as already established species including seven genera belonging to the families Mussidae, Pocilloporidae, Poritidae, Siderastreidae, and Milleporidae; the other three remain in open nomenclature. Nine of the 11 species identified (81%) are extinct. The remaining two living species,Siderastrea sidereaandMillepora alcicornis, are common on modern Caribbean reefs. Their presence in the Siamaná Formation extends their temporal range in the Caribbean region to the early Miocene. Most of the taxa described here were hermatypic and zooxanthellate corals of the order Scleractinia, with the exception of the fire coralMillepora alcicornis, of the order Anthothecata, family Milleporidae. The coral fauna recorded in the Siamaná and Jimol formations is typical of shallow and calm waters of the Oligocene–Miocene transition.
Sylvan Memories of People, Place, and Trees in Nangodi, Northeastern Ghana
Authors: Renne Elisha P.
Published: December 2018

People's relationships with trees reflect the landscape histories associated with distinctive forms of political and religious authority and the moral imaginings of people in Nangodi and its environs in the Upper East Region of Ghana. Their memories of particular trees serve as historical evidence of overlapping yet specific forms of political authority exercised by chiefs, earth priests, past colonial officers, and present-day Ghanaian government officials. In Nangodi, individual family ancestral tree shrines, clan tree cemeteries, and sacred groves associated with earth priests and chiefs coexist with the Red Volta West Forest Reserve and with a succession of tree-related development initiatives. While these relationships are often considered as separate claims to political authority, spiritual power, or scientific knowledge, this paper argues that these relationships of people and of trees are better conceptualized as historical accumulations that represent intersecting and contested forms of authority and political rule continuing into the present. Indigenous tree species such as ebony are associated with sacred groves controlled by chiefs, silk-cotton trees with earth priests’ cemeteries, and baobab trees with particular families coexist with foreign teak trees associated with colonial forestry. This situation suggests how institutions of governance as well as the actions of individuals have environmental consequences. A consideration of historical memories of people and trees in places such as Nangodi enables a rethinking of political and environmental dichotomies, and complicates the social dynamics of` the preservation and destruction of trees and forests around the world.
Cognitive impairment in substance use disorders
Authors: Ramey Tatiana , Regier Paul S.
Published: December 2018

Cognitive impairments in substance use disorders have been extensively researched, especially since the advent of cognitive and computational neuroscience and neuroimaging methods in the last 20 years. Conceptually, altered cognitive function can be viewed as a hallmark feature of substance use disorders, with documented alterations in the well-known “executive” domains of attention, inhibition/regulation, working memory, and decision-making. Poor cognitive (sometimes referred to as “top-down”) regulation of downstream motivational processes—whether appetitive (reward, incentive salience) or aversive (stress, negative affect)—is recognized as a fundamental impairment in addiction and a potentially important target for intervention. As addressed in this special issue, cognitive impairment is a transdiagnostic domain; thus, advances in the characterization and treatment of cognitive dysfunction in substance use disorders could have benefit across multiple psychiatric disorders. Toward this general goal, we summarize current findings in the abovementioned cognitive domains of substance use disorders, while suggesting a potentially useful expansion to include processes that bothprecede(precognition) andsupersede(social cognition) what is usually thought of as strictly cognition. These additional two areas have received relatively less attention but phenomenologically and otherwise are important features of substance use disorders. The review concludes with suggestions for research and potential therapeutic targeting of both the familiar and this more comprehensive version of cognitive domains related to substance use disorders.
Timothy L. Grove Receives 2018 Harry H. Hess Medal
Authors:   AGU
Published: December 2018

Timothy L. Grove was awarded the 2018 Harry H. Hess Medal at the AGU Fall Meeting Honors Ceremony held on 12 December 2018 in Washington, D. C. The medal is for “outstanding achievements in research on the constitution and evolution of the Earth and other planets.”
Taking Magnetotelluric Data out of the Drawer
Authors: Kelbert Anna , Erofeeva Svetlana , Trabant Chad , Karstens Richard , Van Fossen Mick
Published: December 2018

Magnetic and electric field measurements at Earth’s surface provide information on Earth's interior and on space weather. An open-source central repository of these data has received a major update.
Dynamics of Outgassing and Plume Transport Revealed by Proximal Unmanned Aerial System (UAS) Measurements at Volcán Villarrica, Chile
Authors: Liu Emma J. , Wood Kieran , Mason Emily , Edmonds Marie , Aiuppa Alessandro , Giudice Gaetano , Bitetto Marcello , Francofonte Vincenzo , Burrow Steve , Richardson Thomas , Watson Matthew , Pering Tom D. , Wilkes Thomas C. , McGonigle Andrew J. S. , Velasquez Gabriela , Melgarejo Carlos , Bucarey Claudia
Published: December 2018

Volcanic gas emissions are intimately linked to the dynamics of magma ascent and outgassing and, on geological time scales, constitute an important source of volatiles to the Earth's atmosphere. Measurements of gas composition and flux are therefore critical to both volcano monitoring and to determining the contribution of volcanoes to global geochemical cycles. However, significant gaps remain in our global inventories of volcanic emissions, (particularly for CO2, which requires proximal sampling of a concentrated plume) for those volcanoes where the near‐vent region is hazardous or inaccessible. Unmanned Aerial Systems (UAS) provide a robust and effective solution to proximal sampling of dense volcanic plumes in extreme volcanic environments. Here we present gas compositional data acquired using a gas sensor payload aboard a UAS flown at Volcán Villarrica, Chile. We compare UAS‐derived gas time series to simultaneous crater rim multi‐GAS data and UV camera imagery to investigate early plume evolution. SO2 concentrations measured in the young proximal plume exhibit periodic variations that are well correlated with the concentrations of other species. By combining molar gas ratios (CO2/SO2 = 1.48–1.68, H2O/SO2 = 67–75, and H2O/CO2 = 45–51) with the SO2 flux (142 ± 17 t/day) from UV camera images, we derive CO2 and H2O fluxes of ~150 t/day and ~2,850 t/day, respectively. We observe good agreement between time‐averaged molar gas ratios obtained from simultaneous UAS‐ and ground‐based multi‐GAS acquisitions. However, the UAS measurements made in the young, less diluted plume reveal additional short‐term periodic structure that reflects active degassing through discrete, audible gas exhalations.
Investigating the Accuracy, Precision, and Cooling Rate Dependence of Laboratory‐Acquired Thermal Remanences During Paleointensity Experiments
Authors: Santos C. N. , Tauxe L.
Published: December 2018

We examine the behavior of natural basaltic and trachytic samples during paleointensity experiments on both the original and laboratory‐acquired thermal remanences and characterize the samples using proxies for domain state including curvature (k) and the bulk domain stability parameters of Paterson (2011,https://doi.org/10.1029/2011JB008369) and Paterson et al. (2017,https://doi.org/10.1073/pnas.1714047114), respectively. A curvature value of 0.164 (suggested by Paterson, 2011,https://doi.org/10.1029/2011JB008369) as a critical threshold that separates single‐domain‐like remanences from multidomain‐like remanances on the original paleointensity data was used to separate samples into “straight” (single‐domain‐like) and “curved” (multidomain‐like) groups. Specimens from the two sample sets were given a “fresh” thermal remanent magnetization in a 70 μT field and subjected to an infield‐zerofield, zerofield‐infield (IZZI)‐type (Yu et al., 2004,https://doi.org/10.1029/2003GC000630) paleointensity experiment. The straight sample set recovered the laboratory field with high precision while the curved set had much more scattered results (70.5 ± 1.5 and 71.9 ± 5.2 μT, respectively). The average intensity of both sets for straight and curved was quite close to the laboratory field of 70 μT, however, suggesting that if experiments contain a sufficient number of specimens, there does not seem to be a large bias in the field estimate. We found that the dependence of the laboratory thermal remanent magnetization on cooling rate was significant in most samples and did not depend on domain states inferred from proxies based on hysteresis measurements and should be estimated for all samples whose cooling rates differ from that used in the laboratory.
Trans‐Dimensional Surface Reconstruction With Different Classes of Parameterization
Authors: Hawkins Rhys , Bodin Thomas , Sambridge Malcolm , Choblet Gaël , Husson Laurent
Published: December 2018

The use of Bayesian trans‐dimensional sampling in 2‐D and 3‐D imaging problems has recently become widespread in geophysical inversion. Its benefits include its spatial adaptability to the level of information present in the data and the ability to produce uncertainty estimates. The most used parameterization in Bayesian trans‐dimensional inversions is Voronoi cells. Here we introduce a general software, TransTessellate2D, that allows 2‐D trans‐dimensional inference with Voronoi cells and two alternative underlying parameterizations, Delaunay triangulation with linear interpolation and Clough‐Tocher interpolation, which utilize the same algorithm but result in either C0 or C1 continuity. We demonstrate that these alternatives are better suited to the recovery of smooth models, and show that the posterior probability solution is less susceptible to multimodalities which can complicate the interpretation of model parameter uncertainties.
Distribution of Areal Strain on Mercury: Insights Into the Interaction of Volcanism and Global Contraction
Authors: Peterson Georgia A. , Johnson Catherine L. , Byrne Paul K. , Phillips Roger J.
Published: December 2018

Shortening tectonic structures within Mercury's two largest geological units display a clear contrast in relief, length, and spatial density. The volcanic smooth plains units are deformed by smaller‐scale structures yet host more features per area than the older intercrater plains. Although faulting in the intercrater plains is dominantly attributed to global contraction, it has been unclear whether the smooth plains faults result from volcanic loading, global contraction, or both. We use estimates of fault length and displacement to calculate spatial variations of areal strain for each unit. We find that high strain concentrations within the smooth plains suggest that global contraction has contributed to deformation in these units. The observed contrast in morphology and spatial density of structures between units may primarily reflect differences in mechanical and/or structural characteristics of the lithosphere when faulting was initiated.
High‐Resolution Mapping of Nitrogen Dioxide With TROPOMI: First Results and Validation Over the Canadian Oil Sands
Authors: Griffin Debora , Zhao Xiaoyi , McLinden Chris A. , Boersma Folkert , Bourassa Adam , Dammers Enrico , Degenstein Doug , Eskes Henk , Fehr Lukas , Fioletov Vitali , Hayden Katherine , Kharol Shailesh K. , Li Shao‐Meng , Makar Paul , Martin Randall V. , Mihele Cristian , Mittermeier Richard L. , Krotkov Nickolay , Sneep Maarten , Lamsal Lok N. , Linden Mark ter , Geffen Jos van , Veefkind Pepijn , Wolde Mengistu
Published: December 2018

TROPOspheric Monitoring Instrument (TROPOMI), on‐board the Sentinel‐5 Precurser satellite, is a nadir‐viewing spectrometer measuring reflected sunlight in the ultraviolet, visible, near‐infrared, and shortwave infrared. From these spectra several important air quality and climate‐related atmospheric constituents are retrieved, including nitrogen dioxide (NO2) at unprecedented spatial resolution from a satellite platform. We present the first retrievals of TROPOMI NO2 over the Canadian Oil Sands, contrasting them with observations from the Ozone Monitoring Instrument satellite instrument, and demonstrate TROPOMI's ability to resolve individual plumes and highlight its potential for deriving emissions from individual mining facilities. Further, the first TROPOMI NO2 validation is presented, consisting of aircraft and surface in situ NO2 observations, and ground‐based remote‐sensing measurements between March and May 2018. Our comparisons show that the TROPOMI NO2 vertical column densities are highly correlated with the aircraft and surface in situ NO2 observations, and the ground‐based remote‐sensing measurements with a low bias (15–30 %); this bias can be reduced by improved air mass factors.
Effects of Cross‐Sheet Density and Temperature Inhomogeneities on Magnetotail Reconnection
Authors: Lu San , Artemyev A. V. , Angelopoulos V. , Pritchett P. L. , Runov A.
Published: December 2018

Properties of magnetic reconnection in Earth's magnetotail are determined by prereconnection current sheet characteristics. Although spacecraft observations have revealed that the spatial profiles of two important parameters, density and temperature, across the prereconnection magnetotail current sheet are inhomogeneous, the effects of the inhomogeneities on reconnection processes have received insufficient attention. Using Time History of Events and Macroscale Interactions during Substorm (THEMIS) and Acceleration, Reconnection, Turbulence, and Electrodynamics of Moon's Interaction with the Sun (ARTEMIS) observations, we show that the inhomogeneities are ubiquitous throughout the magnetotail. Using particle‐in‐cell simulations, we demonstrate that strong density inhomogeneity increases magnetotail reconnection rate, and strong temperature inhomogeneity further increases reconnection outflow speed (although reconnection rate does not change significantly). Overall, these inhomogeneities expedite energy conversion efficiency and secondary plasmoid formation during reconnection. As the current sheet density and temperature characteristics vary considerably with geocentric distance and time under different geospace conditions, a large variety of reconnection and postreconnection dynamics results from this dependence.
Modeling Three‐Dimensional Wave Propagation in Anelastic Models With Surface Topography by the Optimal Strong Stability Preserving Runge‐Kutta Method
Authors: Wang Nian , Li Jiahang , Borisov Dmitry , Gharti Hom Nath , Shen Yang , Zhang Wei , Savage Brian
Published: December 2018

Accurate and efficient forward modeling methods are important for simulation of seismic wave propagation in 3D realistic Earth models and crucial for high‐resolution full waveform inversion. In the presence of attenuation, wavefield simulation could be inaccurate or unstable over time if not well treated, indicating the importance of the implementation of a strong stability preserving time discretization scheme. In this study, to solve the anelastic wave equation, we choose the optimal strong stability preserving Runge‐Kutta (SSPRK) method for the temporal discretization and apply the fourth‐order MacCormack scheme for the spatial discretization. We approximate the rheological behaviors of the Earth by using the generalized Maxwell body model and use an optimization procedure to calculate the anelastic coefficients determined by the Q(ω) law. This optimization constrains positivity of the anelastic coefficients and ensures the decay of total energy with time, resulting in a stable viscoelastic system even in the presence of strong attenuation. Moreover, we perform theoretical and numerical analyses of the SSPRK method, including the stability criteria and the numerical dispersion. Compared with the traditional fourth‐order Runge‐Kutta method, the SSPRK has a larger stability condition number and can better suppress numerical dispersion. We use the complex‐frequency‐shifted perfectly matched layer for the absorbing boundary conditions based on the auxiliary difference equation and employ the traction image method for the free‐surface boundary condition on curvilinear grids representing the surface topography. Finally, we perform several numerical experiments to demonstrate the accuracy of our anelastic modeling in the presence of surface topography.