bluuebunny/crossref_metadata_2025 huggingface dataset:
Integration of the outcrop and subsurface geochemical data: implications for the hydrocarbon source rock evaluation in the Lower Indus Basin, Pakistan
Authors: Ahmad Sajjad , Ahmad Faizan , Ullah Abd , Eisa Muhammad , Ullah Farman , Kaif Khalid , Khan Suleman
Published: October 2018

The present study details the hydrocarbon source rock geochemistry and organic petrography of the outcrop and subsurface samples of the Middle Jurassic Chiltan Formation and the Lower Cretaceous Sembar Formation from the Sann #1 well Central and Southern Indus Basin, Pakistan. The total organic carbon (TOC), Rock–Eval pyrolysis, vitrinite reflectance (Ro) % and Maceral analysis techniques were used and various geochemical plots were constructed to know the quality of source rock, type of kerogen, level of maturity and migration history of the hydrocarbons. The outcrop and Sann #1 well data on the Sembar Formation reveals poor, fair, good and very good quality of the TOC, type II–III kerogen, immature–mature organic matter and an indigenous hydrocarbon generation potential. The outcrop and Sann #1 well data on the Chiltan Formation show a poor–good quality of TOC, type II–III kerogen, immature–mature source rock quality and having an indigenous hydrocarbon generation potential. The vitrinite reflectance [Ro (%)] values and Maceral types [fluorescent amorphous organic matter, exinite, alginite and inertnite] demonstrate that maturity in both Sembar and the Chiltan formation at surface and subsurface fall in the oil and gas generation zone to cracking of oil to gas condensate zone. Recurrence of organic rich and poor intervals within the Sembar and Chiltan formation are controlled by the Late Jurassic thermal uplift preceding the Indo-Madagascar separation from the Afro-Arabian Plate and Early Cretaceous local transgressive–regressive cycles. From the current study, it is concluded that both Sembar and Chiltan formation can act as a potential hydrocarbon source rock in the study area.
Hypertension and obesity moderate the relationship between β‐amyloid and cognitive decline in midlife
Authors: Clark Lindsay R. , Koscik Rebecca L. , Allison Samantha L. , Berman Sara E. , Norton Derek , Carlsson Cynthia M. , Betthauser Tobey J. , Bendlin Barbara B. , Christian Bradley T. , Chin Nathaniel A. , Asthana Sanjay , Johnson Sterling C.
Published: October 2018

Background

This study tested if central obesity, hypertension, or depressive symptoms moderated the relationship between β‐amyloid (Aβ) and longitudinal cognitive performance in late middle‐aged adults enriched for Alzheimer's disease (AD) risk.

Methods

Participants (n = 207; ages = 40–70 years; 73% parental AD) in the Wisconsin Registry for Alzheimer's Prevention study completed 3+ neuropsychological evaluations and a [11C]PiB positron emission tomography scan or lumbar puncture. Linear mixed‐effects regression models tested interactions of risk factor × Aβ × visit age on longitudinal Verbal Learning & Memory and Speed & Flexibility factor scores.

Results

The relationship between Aβ and Verbal Learning & Memory decline was moderated by hypertension (χ2(1) = 3.85, P = .04) and obesity (χ2(1) = 6.12, P = .01); those with both elevated Aβ and the risk factor declined at faster rates than those with only elevated Aβ or elevated risk factors.

Conclusion

In this cohort, hypertension and obesity moderated the relationship between Aβ and cognitive decline.
Student-Centered Teaching in Paleontology and Geoscience Classrooms
Authors: Dahl Robyn Mieko
Published: October 2018

Research on learning and cognition in geoscience education research and other discipline-based education communities suggests that effective instruction should include three key components: (a) activation of students' prior knowledge on the subject, (b) an active learning pedagogy that allows students to address any existing misconceptions and then build a new understanding of the concept, and (c) metacognitive reflections that require students to evaluate their own learning processes during the lesson. This Element provides an overview of the research on student-centered pedagogy in introductory geoscience and paleontology courses and gives examples of these instructional approaches. Student-centered learning shifts the power and attention in a classroom from the instructor to the students. In a student-centered classroom, students are in control of their learning experience and the instructor functions primarily as a guide. Student-centered classrooms trade traditional lecture for conceptually-oriented tasks, collaborative learning activities, new technology, inquiry-based learning, and metacognitive reflection.
Analysis of passive flexion in propelling a plunging plate using a torsion spring model
Authors: Arora N. , Kang C.-K. , Shyy W. , Gupta A.
Published: October 2018

We mimic a flapping wing through a fluid–structure interaction (FSI) framework based upon a generalized lumped-torsional flexibility model. The developed fluid and structural solvers together determine the aerodynamic forces, wing deformation and self-propelled motion. A phenomenological solution to the linear single-spring structural dynamics equation is established to help offer insight and validate the computations under the limit of small deformation. The cruising velocity and power requirements are evaluated by varying the flapping Reynolds number ($20\leqslant Re_{f}\leqslant 100$), stiffness (represented by frequency ratio,$1\lesssim \unicode[STIX]{x1D714}^{\ast }\leqslant 10$) and the ratio of aerodynamic to structural inertia forces (represented by a dimensionless parameter$\unicode[STIX]{x1D713}$($0.1\leqslant \unicode[STIX]{x1D713}\leqslant 3$)). For structural inertia dominated flows ($\unicode[STIX]{x1D713}\ll 1$), pitching and plunging are shown to always remain in phase ($\unicode[STIX]{x1D719}\approx 0$) with the maximum wing deformation occurring at the end of the stroke. When aerodynamics dominates ($\unicode[STIX]{x1D713}>1$), a large phase difference is induced ($\unicode[STIX]{x1D719}\approx \unicode[STIX]{x03C0}/2$) and the maximum deformation occurs at mid-stroke. Lattice Boltzmann simulations show that there is an optimal$\unicode[STIX]{x1D714}^{\ast }$at which cruising velocity is maximized and the location of optimum shifts away from unit frequency ratio ($\unicode[STIX]{x1D714}^{\ast }=1$) as$\unicode[STIX]{x1D713}$increases. Furthermore, aerodynamics administered deformations exhibit better performance than those governed by structural inertia, quantified in terms of distance travelled per unit work input. Closer examination reveals that although maximum thrust transpires at unit frequency ratio, it is not transformed into the highest cruising velocity. Rather, the maximum velocity occurs at the condition when the relative tip displacement${\approx}\,0.3$.
Marine ice sheet dynamics: the impacts of ice-shelf buttressing
Authors: Pegler Samuel S.
Published: October 2018

Marine ice sheets are continent-scale glacial masses that lie partially submerged in the ocean, as applies to significant regions of Antarctica and Greenland. Such ice sheets have the potential to destabilise under a buoyancy-driven instability mechanism, with considerable implications for future sea level. This paper and its companion present a theoretical analysis of marine ice sheet dynamics under the effect of a potentially dominant control of the buttressing force generated by lateral stresses on the downstream floating component of the ice sheet (the ice shelf). The analysis reveals critical conditions under which ice-shelf buttressing suppresses the buoyancy-driven collapse of an ice sheet and elucidates the implications of lateral stresses on grounding-line control and overall ice-sheet structure. Integrations of a suitably simplified quasi-two-dimensional model are conducted, yielding analytical results that provide a quick assessment of steady-state balances for a given ice-sheet configuration. An analytical balance equation describing the spectrum of marine ice sheet flow regimes spanning zero to strong ice-shelf buttressing is developed. It is determined that the dynamics across this spectrum exhibits markedly different flow regimes and structural characteristics. For sufficient buttressing, the grounding line occurs near to where a lateral-drag controlled section of the ice shelf meets the bedrock, implying an independent control of the grounding line by the ice shelf. The role of basal stresses is relegated to controlling only the thickness of the ice sheet upstream of the grounding line, with no significant control of the grounding line itself. It is further demonstrated that lateral stresses are responsible for inducing additional secondary contacts between the ice shelf and the bedrock downstream of the grounding line, resulting in a rich variety of additional steady states. These inducements generate a further stabilising mechanism that can fully suppress grounding-line retreat and eliminate otherwise irreparable hysteresis effects. The results provide a conceptual framework for numerical and observational interpretation of marine ice sheet dynamics, and clarifies the manner in which ice shelves can control grounding-line positions independently. It is thus indicated that a full resolution of the fine details of the flow of ice shelves and the processes controlling their erosion and disintegration is necessary for the confident forecasting of possible ice-sheet collapse over the course of the next few centuries.
Machine learning the kinematics of spherical particles in fluid flows
Authors: Wan Zhong Yi , Sapsis Themistoklis P.
Published: October 2018

Numerous efforts have been devoted to the derivation of equations describing the kinematics of finite-size spherical particles in arbitrary fluid flows. These approaches rely on asymptotic arguments to obtain a description of the particle motion in terms of a slow manifold. Here we present a novel approach that results in kinematic models with unprecedented accuracy compared with traditional methods. We apply a recently developed machine learning framework that relies on (i) an imperfect model, obtained through analytical arguments, and (ii) a long short-term memory recurrent neural network. The latter learns the mismatch between the analytical model and the exact velocity of the finite-size particle as a function of the fluid velocity that the particle has encountered along its trajectory. We show that training the model for one flow is sufficient to generate accurate predictions for any other arbitrary flow field. In particular, using as an exact model for trajectories of spherical particles, the Maxey–Riley equation, we first train the proposed machine learning framework using trajectories from a cellular flow. We are then able to accurately reproduce the trajectories of particles having the same inertial parameters for completely different fluid flows: the von Kármán vortex street as well as a two-dimensional turbulent fluid flow. For the second example we also demonstrate that the machine learned kinematic model successfully captures the spectrum of the particle velocity, as well as the extreme event statistics. The proposed scheme paves the way for machine learning kinematic models for bubbles and aerosols using high-fidelity DNS simulations and experiments.
Assessment of the nutrition environment in rural counties in the Deep South
Authors: Shikany James M. , Carson Tiffany L. , Hardy Claudia M. , Li Yufeng , Sterling Samara , Hardy Sharonda , Walker Cordie M. , Baskin Monica L.
Published: October 2018

The nutrition environment, including food store type, may influence dietary choices, which in turn can affect risk of obesity and related chronic diseases such as CHD, diabetes and cancer. The objective of the present study was to elucidate the extent to which healthy foods are available and affordable in various rural food outlets. A subset of the nutrition environment was assessed using the Nutrition Environment Measures Survey in Stores (NEMS-S). The NEMS-S instrument assessed the availability and price of healthy foods (e.g. low-fat/non-fat milk, lean meats and reduced-fat dinner entrées) compared with less healthy counterparts (e.g. whole milk, non-lean meats and regular dinner entrées). The NEMS-S also assessed the quality of fresh fruits and vegetables. Availability, prices and quality of healthy foods were compared between grocery stores (n 24) and convenience stores (n 67) in nine rural counties in Alabama. Mean availability subscale score (possible range 0 to 30; higher score indicates a greater number of healthier foods were available) for grocery stores was 22·6 (sd 8·1), compared with 6·6 (sd 5·2) in convenience stores (P < 0·0001); and mean price subscale score (possible range −9 to 18; higher score indicates that healthier options were less expensive than the less healthy options) for grocery stores was 2·4 (sd 2·7), compared with 0·7 (sd 1·2) in convenience stores (P = 0·0080). Mean total NEMS-S score (possible range −9 to 54) in grocery stores was 29·8 (sd 10·9) compared with 7·3 (sd 7·1) in convenience stores (P < 0·0001). Both grocery and convenience stores could be strategic points of intervention to improve the nutrition environment in the counties that were surveyed.
The Long-Term Effects of Foreign Investment on Local Human Capital: Four American Companies in Spain, 1920s–1970s
Authors: Puig Núria , Álvaro-Moya Adoración
Published: October 2018

This article explores the long-term effects of foreign direct investment on the human capital development of host economies, based on the historical analysis of the Spanish operations of four leading American firms: ITT, J. Walter Thompson, Merck Sharp & Dohme, and John Deere. Our research shows that the training and working practices of these companies had a positive impact on the Spanish subsidiaries in terms of technological upgrading and managerial development. However, the local context was also relevant, through mandatory agreements that empowered local partners from the start and the availability of locally educated professionals eager to absorb new knowledge.
Effects of temperature onParamoeba peruransgrowth in culture and the associated microbial community
Authors: Benedicenti O. , Secombes C. J. , Collins C.
Published: October 2018

Population growth,in vitro, of threeParamoeba peruranscultures, one polyclonal (G) and two clonal (B8, CE6, derived from G), previously shown to differ in virulence (B8 > G > CE6), was compared at 10 and 15 °C. B8 showed a significantly higher increase in attached and in suspended amoebae over time at 15 and 10 °C, respectively. CE6 and G also had significantly higher numbers of suspended amoebae at 10 °C compared with 15 °C at experiment termination. However, in contrast to B8, numbers of attached amoebae were significantly higher at 10 °C in CE6 but showed a similar trend in G at the end of the experiment. Numbers of both suspended and attached amoebae were lower in B8 compared with CE6 and G. Significant differences in bacterial community composition and/or relative abundances were found, between cultures, between temperatures and between the same culture with and without amoebae, based on 16S rRNA Illumina MiSeq sequencing. Bacterial diversity was lower in B8 and CE6 compared with G, possibly reflecting selection during clonal isolation. The results indicate that polyclonalP. peruranspopulations may contain amoebae displaying different growth dynamics. Further studies are required to determine if these differences are linked to differences seen in the bacterial communities.
Neuroinflammation in schizophrenia: meta-analysis ofin vivomicroglial imaging studies
Authors: Marques Tiago Reis , Ashok Abhishekh H , Pillinger Toby , Veronese Mattia , Turkheimer Federico E. , Dazzan Paola , Sommer Iris E.C. , Howes Oliver D
Published: October 2018

Background

Converging lines of evidence implicate an important role for the immune system in schizophrenia. Microglia are the resident immune cells of the central nervous system and have many functions including neuroinflammation, axonal guidance and neurotrophic support. We aimed to provide a quantitative review ofin vivoPET imaging studies of microglia activation in patients with schizophrenia compared with healthy controls.

Methods

Demographic, clinical and imaging measures were extracted from each study and meta-analysis was conducted using a random-effects model (Hedge'sg). The difference in 18-kDa translocator protein (TSPO) binding between patients with schizophrenia and healthy controls, as quantified by either binding potential (BP) or volume of distribution (VT), was used as the main outcome. Sub-analysis and sensitivity analysis were carried out to investigate the effects of genotype, ligand and illness stage.

Results

In total, 12 studies comprising 190 patients with schizophrenia and 200 healthy controls met inclusion criteria. There was a significant elevation in tracer binding in schizophrenia patients relative to controls when BP was used as an outcome measure, (Hedge'sg= 0.31;p= 0.03) but no significant differences whenVTwas used (Hedge'sg= −0.22;p= 0.29).

Conclusions

In conclusion, there is evidence for moderate elevations in TSPO tracer binding in grey matter relative to other brain tissue in schizophrenia when using BP as an outcome measure, but no difference when VT is the outcome measure. We discuss the relevance of these findings as well as the methodological issues that may underlie the contrasting difference between these outcomes.
X-ray powder diffraction of mineral pigments and medicines from the 17th century pharmacy (Spezieria) Santa Maria della Scala in Rome, Italy
Authors: Cavallo Giovanni , Vázquez de Ágredos Pascual Maria Luisa
Published: October 2018

The pharmacy (spezieria) Santa Maria della Scala was founded in Rome by the Discalced Carmelites Order in the 17th century, and during the 18th and 19th centuries it became the official supplier of medicines for Vatican Popes. The laboratory and the cases of this spezieria still preserve glass jars with organic and inorganic materials, which were presumably used for medicine and artistic material preparation, whose composition is unknown to date. A research project was initiated with the aim to study the stored materials and the role that the pharmacy played in regional, national and international contexts. In this manuscript, the compounds were analysed through X-ray powder diffraction with the scope to derive the quantitative mineralogical composition of the inorganic fraction, their possible use in pharmacopoeias and as mineral pigments. Most of the analysed samples are salts (sulphates, chlorides, carbonates, phosphates, borates, sulphides), sulphates being the predominant class; oxides were also detected.
“The Fathers have eaten Sour Grapes, and the Children’s Teeth are set on Edge”: Differentiating the Emotional Experiences of Grima and Disgust
Authors: Schweiger Gallo Inge , Rodríguez Monter Miryam , Álvaro-Estramiana José Luis , Durán Juan Ignacio , Fernández-Dols José-Miguel
Published: October 2018

The Spanish termgrimarefers to the aversive emotional experience typically evoked when one hears, for example, a scratch upon a chalkboard. Whereas Spanish speakers can distinguish between the concepts of grima and disgust, English and German speakers lack a specific word for this experience and typically label grima as disgust. In the present research, we tested the degree of differentiation between the two aversive experiences in Spanish speakers. Study 1 addressed whether Spanish speakers apply spontaneously the term grima rather than disgust to grima-eliciting experiences. Study 2 systematically addressed the constitutive features of both grima and disgust by mapping their internal structures. Results showed that the noise of a chulk on a blackboard and scraping fingernails on a blackboard, along with the physical manifestation of goose bumps, were the most typical features of the category. Whereas both grima and disgust were characterized as unpleasant sensations,t(193) = 1.21,ns, they differed with respect to their physiological signatures (e.g., producing shivers was characteristic of grima, as compared to disgust,t(194) = 12.02,p= .001,d= 1.72) and elicitors (e.g., a fractured bone was a characteristic elicitor of grima;t(193) = 5.78,p= .001,d= .83, whereas pederasts and pedophiles were the most characteristic elicitor of disgust,t(193) = 8.46,p= .001,d= 1.21). Thus, both grima and disgust are conceptually different experiences, whose shared features hold different degrees of typicality. The present research suggests that grima and disgust are two distinct emotion concepts.
Rule Emission: A Possible Variable for Improved Therapeutic Practice
Authors: Vargas-de la Cruz Ivette , Pardo-Cebrián Rebeca , Martínez Sánchez Héctor , Froján-Parga María Xesús
Published: October 2018

It has been suggested that achieving greater effectiveness in psychotherapeutic treatment requires analyzingwhattherapists actuallydoand say,howthey do this andwhenit is done. Based on this approach, in this study we focused on the rules emitted by therapists, since providing rules is thought to be of fundamental importance in promoting effective and efficient clinical change. Specifically, we sought to determine whether the experience level of therapists and the brevity of therapy would be related to patterns of therapist rule emission as categorized by the Category System of Rules emitted by the Therapist (SISC-RULES-T) (Vargas-de la Cruz & Pardo-Cebrián, 2014). Greater therapist experience and shorter therapy duration were found to be reliably predictive of more rule emissions across most rule categories (Zvalues between:Z= –3.68 andZ= –2.05;pvalues:p< .05 andp< .001). These variables were also predictive of more emissions of rules that specified all three operant contingency elements (situation, behavior, and consequence) rather than fewer elements (Z= –2.59,p< .05;Z= –2.26,p< .05). In the expert therapists and therapist with shorter cases, there was a nonsignificant tendency for the emission of general and conceptual rules to increase over sessions whereas emissions of concrete and particular rules tended to decrease; the explicitness of the three contingency elements also tended to decrease as treatment progressed. These findings may help to identify verbal characteristics of therapists that could lead to improved therapeutic practice.
The Pernicious Effects of Malicious versus Benign Envy: Perceived Injustice, Emotional Hostility and Counterproductive Behaviors in the Workplace
Authors: Navarro-Carrillo Ginés , Beltrán-Morillas Ana M. , Valor-Segura Inmaculada , Expósito Francisca
Published: October 2018

Despite the fact that literature regarding the implications of envy in the work environment has generated growing interest in recent years, the role of malicious and benign envy in the workplace has scarcely been studied. Therefore, the present study, using an experimental design,N= 213 (140 female and 73 male;Mage= 31.05,SD= 10.01; range from 18 to 68), aims to examine the effects of malicious (vs. benign) envy on perceived injustice, negative emotions, and the individual tendency to express counterproductive work behaviors. The results obtained showed that the mere activation of malicious envy (vs. benign envy) leads to an increased perceived injustice (p< .001, ηp2=.15), and to higher levels of negative emotions (p< .001, ηp2=.18) and counterproductive (harmful) behaviors toward the envied co-worker (p< .001, ηp2=.16). Additionally, we found that perceptions of injustice and negative emotions mediated the effect of malicious (vs. benign) envy on the inclination to express counterproductive work behaviors (Indirect Effect (IE) = .227,SE= .064, 95% CI [.127, .386]. Finally, these findings and their possible implications are discussed.
Polish Economists in Nehru's India: Making Science for the Third World in an Era of De-Stalinization and Decolonization
Authors: Mazurek Małgorzata
Published: October 2018

Between 1956–68 economic expertise became Poland's key export product in the decolonizing world. India, a broker of social science in the Cold War, became a geopolitical gateway for Polish economists’ spread of developmental thinking that revived heterodox Marxism and peasant studies. In this article, Małgorzata Mazurek investigates epistemic and intellectual effects of Polish – Indian encounters and how they evolved separately from Soviet Third World politics. Mazurek argues that during de-Stalinization and decolonization, failures and obstacles to planning and land reforms came to be seen as a common ground between eastern Europe and South Asia. This shared perception also revived the historical legacy of central and east European social science, which was internationalized in new ways both because, and in spite, of the Cold War.
Assimilation of IASI Ozone‐Sensitive Channels in Preparation for an Enhanced Coupling Between Numerical Weather Prediction and Chemistry Transport Models
Authors: Coopmann O. , Guidard V. , Fourrié N. , Plu M.
Published: October 2018

In this study, IASI ozone‐sensitive channels have been assimilated in 1D‐Var data assimilation combined with realistic ozone background coming from a MOCAGE (Modèle de Chimie Atmosphérique à Grande Echelle) Chemistry Transport Model (CTM) as a first stage of coupling between Numerical Weather Prediction (NWP) and MOCAGE CTM at Météo‐France for global model ARPEGE (Action de Recherche Petite Echelle Grande Echelle). To evaluate the impact of ozone‐sensitive channels on analyses, databases of 161 temperatures, humidity, and ozone radiosondes across the globe during a 1‐year period have been considered. Ozone forecast from MOCAGE CTM was evaluated with radiosondes and used as input for the Radiative Transfer Model (RTM) RTTOV. Statistics of IASI observations minus simulations show that the use of ozone from MOCAGE CTM allows to better simulate IASI ozone‐sensitive channels. The Desroziers method is used to diagnose observation error covariance matrix and estimate realistic ozone observation standard errors taking into account cross‐correlations between IASI channels. The background error covariance matrix for ozone is estimated using radiosondes. A control run assimilating 123 IASI operational channels is compared to an experiment which assimilates, in addition, 15 IASI ozone‐sensitive channels. Results show potential benefits of IASI ozone‐sensitive channels combined with realistic ozone from MOCAGE CTM to improve temperature, humidity and ozone analyses simultaneously. This work is an encouraging first step for the enhancing of the coupling between the global model ARPEGE and MOCAGE CTM.
Upward Frequency Sweeping Due to the Nonlinear Resonance of Multiwave Coupling and Its Significant Contribution to the Hall Effect at the Reconnection Point
Authors: Huang Fucheng , Feng Xueshang
Published: October 2018

We suggest a nonlinear resonance mechanism to explain how the Hall term predominates the convection term at the reconnection point during magnetic reconnection quantitatively. Both the case with guide field and that without guide field are run in this simulation. The new findings are as follows: (1) The Hall term compared to the convection term can reach the order of several tens with sharp peaks at the reconnection point in the former case. (2) The frequency range of electrostatic waves at the reconnection point in the former case is broader than that in the latter case. (3) The instantaneous frequency of x or z component of the Hall term can pulse instantly in the former case, and it can exceed the order of 10 in this case. The upward frequency sweeping due to the nonlinear resonance of multiwave coupling is inferred to be responsible for the above simulation results.
High Ice Purity of Martian Lobate Debris Aprons at the Regional Scale: Evidence From an Orbital Radar Sounding Survey in Deuteronilus and Protonilus Mensae
Authors: Petersen Eric Ivan , Holt John W. , Levy Joseph S.
Published: October 2018

Lobate Debris Aprons (LDA) are martian landforms with a strong morphologic resemblance to rock glaciers and debris‐covered glaciers. While the Shallow Radar (SHARAD) sounder has confirmed that a handful of LDA are composed of >80% water ice, viscous flow morphology can also be produced by as little as 30% ice. To distinguish between these endmembers, we conducted a comprehensive regional SHARAD survey of LDA, in Deuteronilus Mensae. We found that the majority of LDA are penetrated by SHARAD and determined that they are composed of a material with
and tanδ≈0.002 < 0.005. These LDA are thus consistently composed of >80% water ice, which constrains the regional sequestered ice budget to a minimum of 0.9 − 1.0 × 105 km3 or a 62–69‐cm Global Equivalent Layer.
Video Transects Reveal That Tidal Sand Waves Affect the Spatial Distribution of Benthic Organisms and Sand Ripples
Authors: Damveld J. H. , van der Reijden K. J. , Cheng C. , Koop L. , Haaksma L. R. , Walsh C. A. J. , Soetaert K. , Borsje B. W. , Govers L. L. , Roos P. C. , Olff H. , Hulscher S. J. M. H.
Published: October 2018

The sandy seabed of shallow coastal shelf seas displays morphological patterns of various dimensions. The seabed also harbors a rich ecosystem. Increasing pressure from human‐induced disturbances necessitates further study on drivers of benthic community distributions over morphological patterns. Moreover, a greater understanding of the sand ripple distribution over tidal sand waves may improve morphological model predictions. Here we analyzed the biotic abundance and ripple morphology in sand wave troughs and crests using video transects. We found that both the epibenthos and endobenthos are significantly more abundant in sand wave troughs, where ripples are less abundant and more irregularly shaped. Finally, we show that camera systems are relatively quick and effective tools to study biotic spatial patterns in relation to seabed morphology.
Global Assessment of Supraglacial Debris‐Cover Extents
Authors: Scherler Dirk , Wulf Hendrik , Gorelick Noel
Published: October 2018

Rocky debris on glacier surfaces influences ice melt rates and the response of glaciers to climate change. However, scarce data on the extent and evolution of supraglacial debris cover have so far limited its inclusion in regional to global glacier models. Here we present global data sets of supraglacial debris‐cover extents, based on Landsat 8 and Sentinel‐2 optical satellite imagery. We find that about 4.4% (~26,000 km2) of all glacier areas (excluding the Greenland ice sheet and Antarctica) are covered with debris, but that the distribution is heterogeneous. The largest debris‐covered areas are located in high‐mountain ranges, away from the poles. At a global scale, we find a negative scaling relationship between glacier size and percentage of debris. Therefore, the influence of debris cover on glacier mass balances is expected to increase in the future, as glaciers continue to shrink.
Energetic Electron Precipitation Associated With Pulsating Aurora Observed by VLF Radio Propagation During the Recovery Phase of a Substorm on 27 March 2017
Authors: Tsuchiya F. , Hirai A. , Obara T. , Misawa H. , Kurita S. , Miyoshi Y. , Shiokawa K. , Connors M. , Ozaki M. , Kasahara Y. , Kumamoto A. , Kasaba Y. , Matsuoka A. , Shoji M. , Shinohara I.
Published: October 2018

Recent studies suggest that electrons with energies up to several hundred keV precipitate into the atmosphere associated with pulsating aurora (PsA). It is debated the highest energy of precipitating electrons associated with PsA. Here we report for the first time that the energy extends to relativistic energies. PsA was observed by THEMIS all‐sky imagers during a substorm that occurred on 27 March 2017. Energetic electron precipitation was detected by very low frequency subionospheric propagation. We found similar time variations between the auroral intensity and perturbation of the received radio signal intensity when the PsA occurred on the radio path. The perturbation showed a short recovery time of ~2 s. The recovery time indicates relaxation from ionospheric modification due to energetic electron precipitation and depends on the stopping altitude of the electrons. The recovery time required a stopping altitude of 50–60 km and indicates that the PsA is accompanied by relativistic electron precipitation.
Estimated Heat Budget During Summer Melt of Arctic First‐Year Sea Ice
Authors: Skyllingstad Eric D. , Polashenski Chris
Published: October 2018

Melt ponds on summer Arctic sea ice control surface albedo, governing energy and mass balance of the ice. The date ponds first form has been connected to interannual variations in ice retreat. Here we evaluate the surface energy balance that governs this critical pond formation date. A three‐dimensional sea ice model with resolved melt ponds is used to diagnose pond onset date at a coastal site across years with observed surface fluxes but incomplete pond observations. Results show that the combined sensible and latent heat flux is the best predictor of pond formation date. This finding supports the hypothesis that synoptic weather events transporting warm, moist air into the Arctic are key to initiating pond formation, triggering albedo feedbacks, and, by extension, ice retreat. Changes in timing and frequency of spring warm air incursions may have significant implications on the ice cover and provide predictive power over seasonal ice retreat.
Mapping Ice Algal Blooms in Southwest Greenland From Space
Authors: Wang Shujie , Tedesco Marco , Xu Min , Alexander Patrick M.
Published: October 2018

Quantifying the distribution and abundance of ice algae is fundamental for understanding the evolving processes of algal blooms in supraglacial environments, particularly over the Greenland ice sheet, given the role of algal impurities in modulating surface albedo and meltwater production. Field observations of ice algae in Greenland are very limited over space and time. Here we show for the first time the regional variability in algal abundance across the dark zone in southwest Greenland, derived from Sentinel‐3 images acquired during the summertime in 2016 and 2017. We demonstrate the capacity of Sentinel‐3 imagery to characterize the spatial pattern of algal abundance using the reflectance ratios between 709‐ and 673‐nm bands, highly consistent with field measurements. The estimated algal abundance reveals a significant linear growth pattern of algal population with time after the peak of dark ice presence, shown to be tightly linked to surface runoff and meltwater production.
Field Observations of Turbulence, Sand Suspension, and Cross‐Shore Transport Under Spilling and Plunging Breakers
Authors: Aagaard Troels , Hughes Michael G. , Ruessink Gerben
Published: October 2018

Measurements of wave orbital velocity, near‐bed turbulence levels, and sediment suspension were obtained under plunging and spilling breakers in the outer surf zone on the beach at Vejers, Denmark. For the same range of relative wave heights and indicators of wave nonlinearity, we observed significantly larger suspended sediment concentrations and onshore‐directed rates of suspended sediment transport under (long period) plunging breakers, compared to (short period) spilling breakers. This is consistent with the long‐held understanding that, for a given beach slope, onshore transport and beach accretion are associated with longer‐period waves and offshore transport and erosion are associated with shorter‐period waves. An intra‐wave analysis of hydrodynamics and sediment suspension revealed that the main reason for the larger suspended sediment transport rates under plunging waves was (i) larger time‐averaged suspended sediment loads under plunging waves, and (ii) a larger difference in cumulated sediment load under the wave crest phase compared to the wave trough phase for plunging breakers. This latter difference was due to an earlier arrival at the seabed of higher levels of turbulent kinetic energy under plunging waves compared to spilling waves. Hence, both magnitude and timing within the wave cycle of turbulent kinetic energy production are important in a quantification of sediment transport under breaking waves. For ensemble‐averaged intense suspension events, contributing roughly 50% of the total sediment suspension during individual records, we found that instantaneous near‐bed sediment load was linearly related to instantaneous levels of Froude‐scaled turbulent kinetic energy.
Sensitivity of the Simulated Tropical Cyclone Intensification to the Boundary‐Layer Height Based on a K‐Profile Boundary‐Layer Parameterization Scheme
Authors: Ma Zhanhong , Fei Jianfang , Huang Xiaogang , Cheng Xiaoping
Published: October 2018

The sensitivity of simulated tropical cyclone intensification to the boundary‐layer height is investigated in this study, using the Yonsei University (YSU) scheme to parameterize boundary‐layer processes. Results reveal nonlinear effects of the boundary‐layer height on the intensification of simulated tropical cyclones. For shallow boundary layer (e.g., below 1,000 m), the storm intensification is sensitive to the depth of the boundary layer; decreasing the boundary‐layer height would lead to a progressive increase in the intensification. For deep boundary layer, the storm intensification is weakly affected by the boundary‐layer height. The roles of unbalanced processes are primarily responsible for these discrepancies. The frictional dissipation is confined in a relatively thin layer for shallow boundary layer, and decreasing the boundary‐layer height causes a larger extent of gradient wind imbalance and stronger radial inflow in the boundary layer. As a consequence, the unbalanced flow effects are more pronounced and contribute to a more rapidly intensifying tropical cyclone. The vertical mixing is intense in a deep boundary layer, resulting in weak unbalanced processes; therefore, further enhancing the boundary‐layer height has less appreciable influence on the tropical cyclone intensification than that in a shallow boundary layer. Increasing the boundary‐layer height has also consequences of drying and warming the lower part of the boundary layer while moistening and cooling the atmosphere aloft, which may be favorable for encouraging outer‐core convection activities. These results underscore the importance of accurately estimating the boundary‐layer height in a K‐profile boundary‐layer scheme for tropical cyclone simulations.
Time Domain Simulation of Geomagnetically Induced Current (GIC) Flowing in 500‐kV Power Grid in Japan Including a Three‐Dimensional Ground Inhomogeneity
Authors: Nakamura S. , Ebihara Y. , Fujita S. , Goto T. , Yamada N. , Watari S. , Omura Y.
Published: October 2018

We performed 3‐D time domain simulation of geomagnetically induced currents (GICs) flowing in the Japanese 500‐kV power grid. The three‐dimensional distribution of the geomagnetically induced electric field (GIE) was calculated by using the finite difference time domain method with a three‐dimensional electrical conductivity model constructed from a global relief model and a global map of sediment thickness. First, we imposed a uniform sheet current at 100‐km altitude with a sinusoidal perturbation to illuminate the influence of the structured ground conductivity on GIE and GIC. The simulation result shows that GIE exhibits localized, uneven distribution that can be attributed to charge accumulation due to the inhomogeneous conductivity below the Earth's surface. The charge accumulation becomes large when the conductivity gradient vector is parallel or antiparallel to the incident electric field. For given GIE, we calculated the GICs flowing in a simplified 500‐kV power grid network in Japan. The influence of the inhomogeneous ground conductivity on GIC appears to depend on a combination of the location of substations and the direction of the source current. Uneven distribution of the power grid system gives rise to intensification of the GICs flowing in remote areas where substations/power plants are distributed sparsely. Second, we imposed the sheet current with its intensity inferred from the ground magnetic disturbance for the magnetic storm of 27 May 2017. We compared the calculated GICs with the observed ones at substations around Tokyo and found a certain agreement when the uneven distribution of GIE is incorporated with the simulation.
Genome-wide association study of brain amyloid deposition as measured by Pittsburgh Compound-B (PiB)-PET imaging
Authors:   for the Alzheimer’s Disease Neuroimaging Initiative (ADNI), Yan Qi , Nho Kwangsik , Del-Aguila Jorge L. , Wang Xingbin , Risacher Shannon L. , Fan Kang-Hsien , Snitz Beth E. , Aizenstein Howard J. , Mathis Chester A. , Lopez Oscar L. , Demirci F. Yesim , Feingold Eleanor , Klunk William E. , Saykin Andrew J. , Cruchaga Carlos , Kamboh M. Ilyas
Published: October 2018

Deposition of amyloid plaques in the brain is one of the two main pathological hallmarks of Alzheimer’s disease (AD). Amyloid positron emission tomography (PET) is a neuroimaging tool that selectively detects in vivo amyloid deposition in the brain and is a reliable endophenotype for AD that complements cerebrospinal fluid biomarkers with regional information. We measured in vivo amyloid deposition in the brains of ~1000 subjects from three collaborative AD centers and ADNI using 11C-labeled Pittsburgh Compound-B (PiB)-PET imaging followed by meta-analysis of genome-wide association studies, first to our knowledge for PiB-PET, to identify novel genetic loci for this endophenotype. The APOE region showed the most significant association where several SNPs surpassed the genome-wide significant threshold, with APOE*4 being most significant (P-meta = 9.09E-30; β = 0.18). Interestingly, after conditioning on APOE*4, 14 SNPs remained significant at P < 0.05 in the APOE region that were not in linkage disequilibrium with APOE*4. Outside the APOE region, the meta-analysis revealed 15 non-APOE loci with P < 1E-05 on nine chromosomes, with two most significant SNPs on chromosomes 8 (P-meta = 4.87E-07) and 3 (P-meta = 9.69E-07). Functional analyses of these SNPs indicate their potential relevance with AD pathogenesis. Top 15 non-APOE SNPs along with APOE*4 explained 25–35% of the amyloid variance in different datasets, of which 14–17% was explained by APOE*4 alone. In conclusion, we have identified novel signals in APOE and non-APOE regions that affect amyloid deposition in the brain. Our data also highlights the presence of yet to be discovered variants that may be responsible for the unexplained genetic variance of amyloid deposition.
Autophagy modulates temozolomide-induced cell death in alveolar Rhabdomyosarcoma cells
Authors: Moghadam Adel Rezaei , da Silva Rosa Simone C. , Samiei Ehsan , Alizadeh Javad , Field Jared , Kawalec Philip , Thliveris James , Akbari Mohsen , Ghavami Saeid , Gordon Joseph W.
Published: October 2018

Rhabdomyosarcoma (RMS) is a muscle-derived tumor. In both pre-clinical and clinical studies Temozolomide (TMZ) has been recently tested against RMS; however, the precise mechanism of action of TMZ in RMS remains unclear. Here we demonstrate that TMZ decreases the cell viability of the RH30 RMS and C2C12 cell line, where cells display evidence of mitochondrial outer membrane permeability. Interestingly, the C2C12 mouse myoblast line was relatively more resistant to TMZ-induced apoptosis. Moreover, we observed that TMZ activated biochemical and morphological markers of autophagy in both cell lines. Autophagy inhibition in both RH30 and C2C12 cells significantly increased TMZ-induced cell death. In RH30 cells, TMZ increased Mcl-1 and Bax protein expression compared to corresponding time match controls while in C2C12 Mcl-1, Bcl-2, Bcl-XL, and Bax protein expression were not changed. Baf-A1 co-treatment with TMZ significantly decrease Mcl-1 expression compared to TMZ while increase Bax expression in C2C12 cells (Bcl2 and Bcl-XL do not significantly change in Baf-A1/TMZ co-treatment). Using a three-dimensional (3D) C2C12 and RH30 culture model we demonstrated that TMZ is significantly more toxic in RH30 cells (live/dead assay). Additionally, we have observed in our 3D culture model that TMZ induced both apoptosis (cleavage of PARP) and autophagy (LC3-puncta and localization of LC3/p62). Therefore, our data demonstrate that TMZ induces simultaneous autophagy and apoptosis in both RH30 and C2C12 cells in 2D and 3D culture model, where RH30 cells are more sensitive to TMZ-induced death. Furthermore, autophagy serves to protect RH30 cells from TMZ-induced death.
Lévy-like movement patterns of metastatic cancer cells revealed in microfabricated systems and implicated in vivo
Authors: Huda Sabil , Weigelin Bettina , Wolf Katarina , Tretiakov Konstantin V. , Polev Konstantin , Wilk Gary , Iwasa Masatomo , Emami Fateme S. , Narojczyk Jakub W. , Banaszak Michal , Soh Siowling , Pilans Didzis , Vahid Amir , Makurath Monika , Friedl Peter , Borisy Gary G. , Kandere-Grzybowska Kristiana , Grzybowski Bartosz A.
Published: October 2018

Metastatic cancer cells differ from their non-metastatic counterparts not only in terms of molecular composition and genetics, but also by the very strategy they employ for locomotion. Here, we analyzed large-scale statistics for cells migrating on linear microtracks to show that metastatic cancer cells follow a qualitatively different movement strategy than their non-invasive counterparts. The trajectories of metastatic cells display clusters of small steps that are interspersed with long “flights”. Such movements are characterized by heavy-tailed, truncated power law distributions of persistence times and are consistent with the Lévy walks that are also often employed by animal predators searching for scarce prey or food sources. In contrast, non-metastatic cancerous cells perform simple diffusive movements. These findings are supported by preliminary experiments with cancer cells migrating away from primary tumors in vivo. The use of chemical inhibitors targeting actin-binding proteins allows for “reprogramming” the Lévy walks into either diffusive or ballistic movements.
Establishing the effects of mesoporous silica nanoparticle properties on in vivo disposition using imaging-based pharmacokinetics
Authors: Dogra Prashant , Adolphi Natalie L. , Wang Zhihui , Lin Yu-Shen , Butler Kimberly S. , Durfee Paul N. , Croissant Jonas G. , Noureddine Achraf , Coker Eric N. , Bearer Elaine L. , Cristini Vittorio , Brinker C. Jeffrey
Published: October 2018

The progress of nanoparticle (NP)-based drug delivery has been hindered by an inability to establish structure-activity relationships in vivo. Here, using stable, monosized, radiolabeled, mesoporous silica nanoparticles (MSNs), we apply an integrated SPECT/CT imaging and mathematical modeling approach to understand the combined effects of MSN size, surface chemistry and routes of administration on biodistribution and clearance kinetics in healthy rats. We show that increased particle size from ~32- to ~142-nm results in a monotonic decrease in systemic bioavailability, irrespective of route of administration, with corresponding accumulation in liver and spleen. Cationic MSNs with surface exposed amines (PEI) have reduced circulation, compared to MSNs of identical size and charge but with shielded amines (QA), due to rapid sequestration into liver and spleen. However, QA show greater total excretion than PEI and their size-matched neutral counterparts (TMS). Overall, we provide important predictive functional correlations to support the rational design of nanomedicines.