bluuebunny/crossref_metadata_2025 huggingface dataset:
Book Review: The Craft of Librarian Instruction: Using Acting Techniques to Create Your Teaching Presence
Authors: Embry Allison
Published: January 2017

The idea of teaching classes is understandably intimidating to many new library professionals. The prospect of bombing a presentation in front of a room full of familiar classmates is bad enough, never mind the possibility of failure before an audience of strangers when one’s job performance is at stake. Fortunately, The Craft of Librarian Instruction: Using Acting Techniques to Create Your Teaching Presence offers support and real-world advice for new teaching librarians. In a short one hundred pages, the book sidesteps long, heavy-handed chapters, and instead offers up tips that can be immediately practiced and incorporated into one’s teaching.
Book Review: Critical Literacy for Information Professionals
Authors: Agee Ann
Published: January 2017

“Liberating education consists in acts of cognition, not transferrals of information,” wrote Paulo Freire in the Pedagogy of the Oppressed (Herder and Herder 1970, 79). Freire argued that rather than viewing students as empty vessels to be filled with knowledge—termed the “banking model” of education—teachers should recognize and value students’ individual perspectives and life experiences. Today’s critical literacy movement has its roots in Freire’s philosophy. When taught critical literacy methods, students begin from the viewpoint that there can be no single “correct” way to interpret information. Instead, texts should be questioned and read with an eye to the cultural forces that shaped them and the sociopolitical agendas they advance. Critical literacy also incorporates an element of social justice, calling students to actively promote the human rights of all marginalized communities.
Book Review: Exploring Discovery: The Front Door to Your Library’s Licensed and Digitized Content
Authors: Tatum Jennifer
Published: January 2017

Consistently providing users with a reliable and thorough way to search the library’s resources is a daunting and exhausting process. Every system and solution has its own perks and pitfalls, but determining how a system will integrate at your library can seem impossible. Exploring Discovery: The Front Door to Your Library’s Licensed and Digitized Content attempts to provide a window into how other libraries have approached their own problems with discovery and exposes both the successes and the challenges they have encountered.
Book Review: The 101 Most Unusual Diseases and Disorders
Authors: McLaughlin Ryan
Published: January 2017

There is developing public interest in strange and rare medical conditions, as evidenced by the popularity of television programs such as Discovery Life’s Mystery Diagnosis and Animal Planet’s Monsters Inside Me. Of reference works about rare conditions, many focus on specialized topics or are intended for health practitioners. Here, the author, Evelyn B. Kelly, writes in her introduction: “this book is intended for a lay audience who does not necessarily want or need to know all of the medical minutiae related to a particular condition” (xiv). Consequently, The 101 Most Unusual Diseases and Disorders may be an appropriate addition for some non-medical libraries.
Book Review: Campaigning for President in America, 1788–2016
Authors: Moffitt Sally
Published: January 2017

Campaigning for President in America, 1788–2016 is a revised and “streamlined edition” (xv) of the 3-volume 2012 second edition also published by Greenwood (Presidential Campaigns, Slogans, Issues, and Platforms: the Complete Encyclopedia) that removes “all of the stand-alone entries on campaign slogans and most of the more dated campaign issues” (xv). In addition, the “number of separate entries explaining major campaign events” (xv) of the past have also been reduced.
Book Review: ISIS: An Introduction and Guide to the Islamic State
Authors: Singleton Brent D.
Published: January 2017

In the past two years there has been a proliferation of books aimed at educating readers about all aspects of ISIS and its development. While this work falls within this corpus, it is unique in its hybrid reference book format. The first part of the work provides nine sections of topical snapshots such as, “What Is In a Name?: IS, ISIS, ISIL, Da’ash,” “The Attraction of ISIS,” and “ISIS and the Media.” Within some of these sections there are encyclopedic entries arranged topically, for instance under “Leaders of ISIS” four biographies are given. The next part of the work is a typical A-Z encyclopedia of nearly seventy people, places, and ideas associated with the group. The entries are subdivided into sections including, “What is important?” or “Why does it matter?” and “Key events in his life” when discussing people. For subjects covered earlier in the topical portion of the work, there are “see” references back to that section.
From the Editor: "Many Thanks"
Authors: Trott Barry
Published: January 2017

Once again, we are entering the holiday season and it is a good time to thank all of the people who make RUSQ possible. First off, I would like to recognize the members of the RUSQ board for volume 55: Jenny S. Bossaller, PhD; Heidi L. M. Jacobs; Kate Kosturski; Scott Seaman; Carol Singer; Nicolette Sosulski; Laurel Tarulli; David A. Tyckoson; Chiang A. Wang; and Neal Wyatt, PhD. The board members are the first readers of submissions to the journal, and without their thoughtful critiques and keen suggestions for improvements, the pieces that we publish would not be as strong. The board members also offer guidance to the editor in terms of directions for the journals, and I am grateful for their help in making sure that RUSQ is valuable to our readers.
From the President of RUSA: What Is the Value of RUSA to You?
Authors: McManus Alesia M.
Published: January 2017

RUSA is facing some challenges ahead. As I mentioned in my last column, RUSA membership is declining. One of the main impacts of the decline in membership is that we have a deficit budget. We are in the process of drafting some bylaws changes to integrate interest groups into RUSA and to give RUSA more flexibility for dues increases as needed. We want to strengthen our association, which is the professional home within ALA for those of us who work directly with our patrons, users, and learners. The last dues increase of $15 was in 2005, so it has been a long time since we have considered a dues increase. Of course, a dues increase brings the possibility that members will not renew because of financial constraints, but I firmly believe that RUSA is worth the money.
The Alert Collector: Depository Collection Management: Databases and Web-Based Resources as Assessment Tools
Authors: Henriques Charmaine
Published: January 2017

While the “Alert Collector” has generally presented columns on building collections in specific topic areas, it is good to remember that managing collections involves more than just selection. It is essential that we also evaluate and weed collections on the basis of our users’ needs and interests as well as on our institutional policies. Here, Charmaine Henriques, liaison and subject specialist at the Northwestern University Libraries, discusses managing depository collections using two case studies.—Editor
A Reference for That: “What are We Stopping?” And “What is Shifting?”
Authors: Sosulski Nicolette Warisse , Tyckoson David A.
Published: January 2017

Dave Tyckoson, and Nicolette Warisse Sosulski met because Sara Kelly Johns, a mutual friend, told them “you have to meet each other! I don’t know that I know anybody else as obsessed by reference [as you are]!” They friended on Facebook in October 2011 and have been chatting, sharing, and sometimes debating about reference ever since. Dave has had a notable career in academic reference, has written extensively on the reference interview, chaired the committee that developed the RUSA behavioral guidelines, and was the recipient of the 2005 Isadore Gilbert Mudge-R.R. Bowker Award for reference excellence. His most recent contribution to reference literature was the editing of Reimagining Reference in the 21st Century. Dave has been a reference librarian for thirty-eight years—and expects that number to grow.
Iniciativas de diversificação ao cultivo do tabaco no município de Santa Cruz do Sul – RS: um estudo de caso
Authors: Ludtke Rosiéle Cristiane , Rambo Anelise Graciele , Stoffel Janete
Published: January 2017

Este artigo analisa os mecanismos que levam famílias produtoras de tabaco a implementarem iniciativas de diversificação e analisar a dinâmica destas mudanças no município de Santa Cruz do Sul/RS. Pretende-se verificar motivações e alternativas de diversificação da produção na maior região produtora de tabaco do país, e quais políticas públicas são mobilizadas. Para tal, será feita uma análise considerando os reflexos da modernização da agricultura, em especial, sobre a agricultura camponesa, considerando aspectos sociais, econômicos e ambientais. O referencial teórico mobilizado engloba a sociedade de risco de Ulrich Beck e a perspectiva orientada ao ator de Long e Ploeg. Enquanto resultados, verifica-se que as iniciativas de diversificação manifestam uma autoconfrontação aos riscos produzidos pela monocultura do tabaco a qual está pautada nos ditames da Revolução Verde. Essa produção diversificada tende a fortalecer a capacidade de agência dos camponeses, como resposta aos riscos produzidos pela cadeia produtiva do tabaco e emerge de uma perspectiva onde o sujeito camponês, de acordo com sua realidade, seu modo de vida, busca minimizar estes efeitos.
Resgate e conservação da agrobiodiversidade crioula em Ibarama-RS: estratégias de manutenção
Authors: Kaufmann Marielen Priscila , Reiniger Lia Rejane Silveira , Wizniewsky José Geraldo , Muniz Marlove Fátima Brião
Published: January 2017

A experiência centenária de manutenção e conservação das sementes crioulas em Ibarama-RS foi sendo resgatada e valorada, a partir da década de 1990, por iniciativa da Emater/RS-Ascar e apoio de outras instituições, como o Sindicato dos Trabalhadores Rurais de Ibarama e ONGs. Ao longo destes anos, outras instituições, como a Embrapa e a UFSM, contribuíram para a pesquisa e valorização da experiência. O objetivo deste trabalho é caracterizar as estratégias de manutenção da conservação da agrobiodiversidade crioula em Ibarama e relatar os condicionantes favoráveis e limitantes para o pleno desenvolvimento desta atividade. Destaca-se, portanto, a presença da Assistência Técnica, e as parcerias que foram importantes para a atividade, no sentido de estimular a produção científica relacionada à agrobiodiversidade crioula, a divulgação da experiência e o incentivo para o resgate de novas espécies e cultivares crioulas, além da ampliação do número de guardiões. A organização da produção de sementes em maior escala e produzidas com base em princípios ecológicos são as intenções futuras deste grupo que congrega esforços para a atuação na Associação dos Guardiões das Sementes Crioulas, entidade que congrega os principais atores desta experiência.
CREB overexpression in dorsal CA1 ameliorates long-term memory deficits in aged rats
Authors: Yu Xiao-Wen , Curlik Daniel M , Oh M Matthew , Yin Jerry CP , Disterhoft John F
Published: January 2017

The molecular mechanisms underlying age-related cognitive deficits are not yet fully elucidated. In aged animals, a decrease in the intrinsic excitability of CA1 pyramidal neurons is believed to contribute to age-related cognitive impairments. Increasing activity of the transcription factor cAMP response element-binding protein (CREB) in young adult rodents facilitates cognition, and increases intrinsic excitability. However, it has yet to be tested if increasing CREB expression also ameliorates age-related behavioral and biophysical deficits. To test this hypothesis, we virally overexpressed CREB in CA1 of dorsal hippocampus. Rats received CREB or control virus, before undergoing water maze training. CREB overexpression in aged animals ameliorated the long-term memory deficits observed in control animals. Concurrently, cells overexpressing CREB in aged animals had reduced post-burst afterhyperpolarizations, indicative of increased intrinsic excitability. These results identify CREB modulation as a potential therapy to treat age-related cognitive decline.
Exploring conformational equilibria of a heterodimeric ABC transporter
Authors: Timachi M Hadi , Hutter Cedric AJ , Hohl Michael , Assafa Tufa , Böhm Simon , Mittal Anshumali , Seeger Markus A , Bordignon Enrica
Published: January 2017

ABC exporters pump substrates across the membrane by coupling ATP-driven movements of nucleotide binding domains (NBDs) to the transmembrane domains (TMDs), which switch between inward- and outward-facing (IF, OF) orientations. DEER measurements on the heterodimeric ABC exporter TM287/288 from Thermotoga maritima, which contains a non-canonical ATP binding site, revealed that in the presence of nucleotides the transporter exists in an IF/OF equilibrium. While ATP binding was sufficient to partially populate the OF state, nucleotide trapping in the pre- or post-hydrolytic state was required for a pronounced conformational shift. At physiologically high temperatures and in the absence of nucleotides, the NBDs disengage asymmetrically while the conformation of the TMDs remains unchanged. Nucleotide binding at the degenerate ATP site prevents complete NBD separation, a molecular feature differentiating heterodimeric from homodimeric ABC exporters. Our data suggest hydrolysis-independent closure of the NBD dimer, which is further stabilized as the consensus site nucleotide is committed to hydrolysis.
Concerted action of the MutLβ heterodimer and Mer3 helicase regulates the global extent of meiotic gene conversion
Authors: Duroc Yann , Kumar Rajeev , Ranjha Lepakshi , Adam Céline , Guérois Raphaël , Md Muntaz Khan , Marsolier-Kergoat Marie-Claude , Dingli Florent , Laureau Raphaëlle , Loew Damarys , Llorente Bertrand , Charbonnier Jean-Baptiste , Cejka Petr , Borde Valérie
Published: January 2017

Gene conversions resulting from meiotic recombination are critical in shaping genome diversification and evolution. How the extent of gene conversions is regulated is unknown. Here we show that the budding yeast mismatch repair related MutLβ complex, Mlh1-Mlh2, specifically interacts with the conserved meiotic Mer3 helicase, which recruits it to recombination hotspots, independently of mismatch recognition. This recruitment is essential to limit gene conversion tract lengths genome-wide, without affecting crossover formation. Contrary to expectations, Mer3 helicase activity, proposed to extend the displacement loop (D-loop) recombination intermediate, does not influence the length of gene conversion events, revealing non-catalytical roles of Mer3. In addition, both purified Mer3 and MutLβ preferentially recognize D-loops, providing a mechanism for limiting gene conversion in vivo. These findings show that MutLβ is an integral part of a new regulatory step of meiotic recombination, which has implications to prevent rapid allele fixation and hotspot erosion in populations.
Distribution of neurosensory progenitor pools during inner ear morphogenesis unveiled by cell lineage reconstruction
Authors: Dyballa Sylvia , Savy Thierry , Germann Philipp , Mikula Karol , Remesikova Mariana , Špir Róbert , Zecca Andrea , Peyriéras Nadine , Pujades Cristina
Published: January 2017

Reconstructing the lineage of cells is central to understanding how the wide diversity of cell types develops. Here, we provide the neurosensory lineage reconstruction of a complex sensory organ, the inner ear, by imaging zebrafish embryos in vivo over an extended timespan, combining cell tracing and cell fate marker expression over time. We deliver the first dynamic map of early neuronal and sensory progenitor pools in the whole otic vesicle. It highlights the remodeling of the neuronal progenitor domain upon neuroblast delamination, and reveals that the order and place of neuroblasts’ delamination from the otic epithelium prefigure their position within the SAG. Sensory and non-sensory domains harbor different proliferative activity contributing distinctly to the overall growth of the structure. Therefore, the otic vesicle case exemplifies a generic morphogenetic process where spatial and temporal cues regulate cell fate and functional organization of the rudiment of the definitive organ.
Marine turtles are not fussy nesters: a novel test of small-scale nest site selection using structure from motion beach terrain information
Authors: Kelly Ilana , Leon Javier X. , Gilby Ben L. , Olds Andrew D. , Schlacher Thomas A.
Published: January 2017

Background

Nest selection is widely regarded as a key process determining the fitness of individuals and viability of animal populations. For marine turtles that nest on beaches, this is particularly pivotal as the nesting environment can significantly control reproductive success.The aim of this study was to identify the environmental attributes of beaches (i.e., morphology, vegetation, urbanisation) that may be associated with successful oviposition in green and loggerhead turtle nests.

Methods

We quantified the proximity of turtle nests (and surrounding beach locations) to urban areas, measured their exposure to artificial light, and used ultra-high resolution (cm-scale) digital surface models derived from Structure-from-Motion (SfM) algorithms, to characterise geomorphic and vegetation features of beaches on the Sunshine Coast, eastern Australia.

Results

At small spatial scales (i.e., <100 m), we found no evidence that turtles selected nest sites based on a particular suite of environmental attributes (i.e., the attributes of nest sites were not consistently different from those of surrounding beach locations). Nest sites were, however, typically characterised by occurring close to vegetation, on parts of the shore where the beach- and dune-face was concave and not highly rugged, and in areas with moderate exposure to artificial light.

Conclusion

This study used a novel empirical approach to identify the attributes of turtle nest sites from a broader ‘envelope’ of environmental nest traits, and is the first step towards optimizing conservation actions to mitigate, at the local scale, present and emerging human impacts on turtle nesting beaches.
Mineralogical, geochemical, and magnetic signatures of surface sediments from the Canadian Beaufort Shelf and Amundsen Gulf (Canadian Arctic)
Authors: Gamboa Adriana , Montero‐Serrano Jean‐Carlos , St‐Onge Guillaume , Rochon André , Desiage Pierre‐Arnaud
Published: January 2017

Mineralogical, geochemical, magnetic, and siliciclastic grain‐size signatures of 34 surface sediment samples from the Mackenzie‐Beaufort Sea Slope and Amundsen Gulf were studied in order to better constrain the redox status, detrital particle provenance, and sediment dynamics in the western Canadian Arctic. Redox‐sensitive elements (Mn, Fe, V, Cr, Zn) indicate that modern sedimentary deposition within the Mackenzie‐Beaufort Sea Slope and Amundsen Gulf took place under oxic bottom‐water conditions, with more turbulent mixing conditions and thus a well‐oxygenated water column prevailing within the Amundsen Gulf. The analytical data obtained, combined with multivariate statistical (notably, principal component and fuzzy c‐means clustering analyses) and spatial analyses, allowed the division of the study area into four provinces with distinct sedimentary compositions: (1) the Mackenzie Trough‐Canadian Beaufort Shelf with high phyllosilicate‐Fe oxide‐magnetite and Al‐K‐Ti‐Fe‐Cr‐V‐Zn‐P contents; (2) Southwestern Banks Island, characterized by high dolomite‐K‐feldspar and Ca‐Mg‐LOI contents; (3) the Central Amundsen Gulf, a transitional zone typified by intermediate phyllosilicate‐magnetite‐K‐feldspar‐dolomite and Al‐K‐Ti‐Fe‐Mn‐V‐Zn‐Sr‐Ca‐Mg‐LOI contents; and (4) mud volcanoes on the Canadian Beaufort Shelf distinguished by poorly sorted coarse‐silt with high quartz‐plagioclase‐authigenic carbonate and Si‐Zr contents, as well as high magnetic susceptibility. Our results also confirm that the present‐day sedimentary dynamics on the Canadian Beaufort Shelf is mainly controlled by sediment supply from the Mackenzie River. Overall, these insights provide a basis for future studies using mineralogical, geochemical, and magnetic signatures of Canadian Arctic sediments in order to reconstruct past variations in sediment inputs and transport pathways related to late Quaternary climate and oceanographic changes.
Midcrustal shearing and doming in aCenozoic compressive setting along theAilaoShan‐RedRiver shear zone
Authors: Zhang B. , Yin C. Y. , Zhang J. J. , Wang J. M. , Zhong D. L. , Wang Y. , Lai Q. Z. , Yue Y. H. , Zhou Q. Y.
Published: January 2017

The Cenozoic Xuelong Shan antiformal dome is located along the northern segment of the Ailao Shan‐Red River shear zone in Yunnan, China. Subhorizontal foliation in the gneiss core is recognized, representing a broad top‐to‐NE shear initiated under amphibolite facies conditions and propagating into greenschist facies in the mantling schist and strike‐slip shear zone. Microfabrics of crystallographic‐preferred orientations (CPOs) in quartz suggest that the deformation temperatures increased with increasing structural depth from the upper crust (300–500°C) in the mantling schist to the midcrust (15 km or more, ≥650°C) in the gneissic core. This trend is mirrored by variations in the metamorphic grade of the syn‐kinematic mineral assemblages and microstructures, which range from garnet + amphibole + biotite + sillimanite + rutile + feldspar in the core to garnet + staurolite + biotite + epidote + muscovite within the limb units. The dome experienced the following deformation history: (1) a broad top‐to‐NE shear in the subhorizontal foliation of the gneiss core during the first stage of deformation (D1); (2) opposing reverse‐sense shear along the two schist limbs of the dome during contraction‐related doming (D2–D3); (3) sinistral strike‐slip shearing within the eastern limb (D4); and (4) extensional deformation (D5). The structural‐thermal patterns suggest the antiformal dome formation was roughly coeval with top‐to‐NE ductile shearing in the midcrust of Tibet at 32 Ma or earlier. A major implication is that there was a phase of contractional ductile deformation in the region prior to the initiation of strike‐slip deformation.
Metamorphic records for subduction erosion and subsequent underplating processes revealed by garnet‐staurolite‐muscovite schists in central Qiangtang, Tibet
Authors: Zhang Xiu‐Zheng , Dong Yong‐Sheng , Wang Qiang , Dan Wei , Zhang Chunfu , Xu Wang , Huang Ming‐Liang
Published: January 2017

Subduction erosion is confirmed as a crucial geodynamic process of crustal recycling based on geological, geochemical, and geophysical observations at modern convergent plate margins. So far, not a single metamorphic record has been used for constraining a general tectonic evolution for subduction erosion. Here we first revealed metamorphic records for a subduction erosion process based on our study of the Late Paleozoic garnet‐staurolite‐muscovite schists in the central Qiangtang block, Tibet. Provenance analyses suggest that the protoliths of garnet‐staurolite‐muscovite schists have the Northern Qiangtang‐affinity and were deposited in an active continental margin setting. Mineral inclusion data show that the early metamorphic stage (M1) recorded blueschist facies pressure‐temperature (P‐T) conditions of 0.8–1.1 GPa and 402–441°C, indicating that a part of the material from the overriding plate had been abraded into the subduction channel and undergone high‐pressure/low‐temperature metamorphism. The peak metamorphic stage (M2) recorded amphibolite facies P‐T conditions of 0.3–0.5 GPa and 470–520°C. The 40Ar/39Ar cooling ages (263–259 Ma) yielded from muscovite suggest the amphibolite facies metamorphism (>263 Ma) occurred at oceanic subduction stage. The distinctly staged metamorphism defines a clockwise and warming decompression P‐T‐t path which reveals an underplating process following the early subduction erosion. During the tectonic process, the eroded low‐density material escaped from the cold subduction channel and rise upward into the warm middle‐lower crust of the upper plate, undergoing amphibolite facies metamorphism. Our new results revealed a complete evolutional process from the early subduction erosion to the subsequent underplating during the northward subduction of the Paleo‐Tethys Ocean.
Influence of mantle flow on the drainage of eastern Australia since the Jurassic Period
Authors: Salles T. , Flament N. , Müller D.
Published: January 2017

Recent studies of the past eastern Australian landscape from present‐day longitudinal river profiles and from mantle flow models suggest that the interaction of plate motion with mantle convection accounts for the two phases of large‐scale uplift of the region since 120 Ma. We coupled the dynamic topography predicted from one of these mantle flow models to a surface process model to study the evolution of the eastern Australian landscape since the Jurassic Period. We varied the rainfall regime, erodibility, sea level variations, dynamic topography magnitude, and elastic thickness across a series of experiments. The approach accounts for erosion and sedimentation and simulates catchment dynamics. Despite the relative simplicity of our model, the results provide insights on the fundamental links between dynamic topography and continental‐scale drainage evolution. Based on temporal and spatial changes in longitudinal river profiles as well as erosion and deposition maps, we show that the motion of the Australian plate over the convecting mantle has resulted in significant reorganization of the eastern Australian drainage. The model predicts that the Murray river drained eastward between 150 and ∼120 Ma, and switched to westward draining due to the tilting of the Australian plate from ∼120 Ma. First order comparisons of eight modeled river profiles and of the catchment shape of modeled Murray‐Darling Basin are in agreement with present‐day observations. The predicted denudation of the eastern highlands is compatible with thermochronology data and sedimentation rates along the southern Australian margin are consistent with cumulative sediment thickness.
Fidelity of the Sr/Ca proxy in recording ocean temperature in the western Atlantic coral Siderastrea siderea
Authors: Kuffner Ilsa B. , Roberts Kelsey E. , Flannery Jennifer A. , Morrison Jennifer M. , Richey Julie N.
Published: January 2017

Massive corals provide a useful archive of environmental variability, but careful testing of geochemical proxies in corals is necessary to validate the relationship between each proxy and environmental parameter throughout the full range of conditions experienced by the recording organisms. Here we use samples from a coral‐growth study to test the hypothesis that Sr/Ca in the coral Siderastrea siderea accurately records sea‐surface temperature (SST) in the subtropics (Florida, USA) along 350 km of reef tract. We test calcification rate, measured via buoyant weight, and linear extension (LE) rate, estimated with Alizarin Red‐S staining, as predictors of variance in the Sr/Ca records of 39 individual S. siderea corals grown at four outer‐reef locations next to in‐situ temperature loggers during two, year‐long periods. We found that corals with calcification rates < 1.7 mg cm−2 d−1 or < 1.7 mm yr−1 LE returned spuriously high Sr/Ca values, leading to a cold‐bias in Sr/Ca‐based SST estimates. The threshold‐type response curves suggest that extension rate can be used as a quality‐control indicator during sample and drill‐path selection when using long cores for SST paleoreconstruction. For our corals that passed this quality control step, the Sr/Ca‐SST proxy performed well in estimating mean annual temperature across three sites spanning 350 km of the Florida reef tract. However, there was some evidence that extreme temperature stress in 2010 (cold snap) and 2011 (SST above coral‐bleaching threshold) may have caused the corals not to record the temperature extremes. Known stress events could be avoided during modern calibrations of paleoproxies.
Seismic structure of the lithosphere beneath NWNamibia: Impact of the Tristan da Cunha mantle plume
Authors: Yuan Xiaohui , Heit Benjamin , Brune Sascha , Steinberger Bernhard , Geissler Wolfram H. , Jokat Wilfried , Weber Michael
Published: January 2017

Northwestern Namibia, at the landfall of the Walvis Ridge, was affected by the Tristan da Cunha mantle plume during continental rupture between Africa and South America, as evidenced by the presence of the Etendeka continental flood basalts. Here we use data from a passive‐source seismological network to investigate the upper mantle structure and to elucidate the Cretaceous mantle plume‐lithosphere interaction. Receiver functions reveal an interface associated with a negative velocity contrast within the lithosphere at an average depth of 80 km. We interpret this interface as the relic of the lithosphere‐asthenosphere boundary (LAB) formed during the Mesozoic by interaction of the Tristan da Cunha plume head with the pre‐existing lithosphere. The velocity contrast might be explained by stagnated and “frozen” melts beneath an intensively depleted and dehydrated peridotitic mantle. The present‐day LAB is poorly visible with converted waves, indicating a gradual impedance contrast. Beneath much of the study area, converted phases of the 410 and 660 km mantle transition zone discontinuities arrive 1.5 s earlier than in the landward plume‐unaffected continental interior, suggesting high velocities in the upper mantle caused by a thick lithosphere. This indicates that after lithospheric thinning during continental breakup, the lithosphere has increased in thickness during the last 132 Myr. Thermal cooling of the continental lithosphere alone cannot produce the lithospheric thickness required here. We propose that the remnant plume material, which has a higher seismic velocity than the ambient mantle due to melt depletion and dehydration, significantly contributed to the thickening of the mantle lithosphere.
The impact of rapid sediment accumulation on pore pressure development and dehydration reactions during shallow subduction in the Gulf of Alaska
Authors: Meridth Lanie N. , Screaton Elizabeth J. , Jaeger John M. , James Stephanie R. , Villaseñor Tania
Published: January 2017

In the Gulf of Alaska region, sediment has rapidly accumulated (>1 km/my) in the trench sourced from intensified glaciation in the past ∼1.2 million years. This rapid sediment accumulation increases overburden and should accelerate dehydration of hydrous minerals by insulating the underlying sediment column. These processes have the potential to generate fluid overpressures in the low permeability sediments entering the subduction zone. A 1‐D model was developed to simulate dehydration reaction progress and investigate excess pore pressures as sediments approach the trench and are subducted. At the deformation front, simulated temperatures increase by ∼30°C due to the insulating effect of trench sediments. As a result, opal‐A begins to react to form quartz while smectite remains mostly unreacted. Loading due to the trench sediments elevates excess pore pressures to ∼30% of lithostatic pressure at the deformation front; however, deformation front excess pore pressures are sensitive to assumptions about the permeability of outer wedge sediments. If the outer wedge sediments are coarse‐grained and high‐permeability rather than mud‐dominated, excess pore pressures are lower but still have an insulating effect. During early subduction, simulated pore pressures continue to rise and reach ∼70% of lithostatic by 60 km landward. The 1‐D modeling results suggest that the elevated pore pressures are primarily due to loading and that dehydration reactions are not a significant component of excess pore pressure generation at this margin.
TerraFERMA: The Transparent Finite Element Rapid Model Assembler for multiphysics problems in Earth sciences
Authors: Wilson Cian R. , Spiegelman Marc , van Keken Peter E.
Published: January 2017

We introduce and describe a new software infrastructure TerraFERMA, the Transparent Finite Element Rapid Model Assembler, for the rapid and reproducible description and solution of coupled multiphysics problems. The design of TerraFERMA is driven by two computational needs in Earth sciences. The first is the need for increased flexibility in both problem description and solution strategies for coupled problems where small changes in model assumptions can lead to dramatic changes in physical behavior. The second is the need for software and models that are more transparent so that results can be verified, reproduced, and modified in a manner such that the best ideas in computation and Earth science can be more easily shared and reused. TerraFERMA leverages three advanced open‐source libraries for scientific computation that provide high‐level problem description (FEniCS), composable solvers for coupled multiphysics problems (PETSc), and an options handling system (SPuD) that allows the hierarchical management of all model options. TerraFERMA integrates these libraries into an interface that organizes the scientific and computational choices required in a model into a single options file from which a custom compiled application is generated and run. Because all models share the same infrastructure, models become more reusable and reproducible, while still permitting the individual researcher considerable latitude in model construction. TerraFERMA solves partial differential equations using the finite element method. It is particularly well suited for nonlinear problems with complex coupling between components. TerraFERMA is open‐source and available at http://terraferma.github.io, which includes links to documentation and example input files.
Note on the Pantellini et al. process for dust impact signals on spacecraft
Authors: Kellogg Paul J.
Published: January 2017

In some recent papers it has been proposed that thick antennas are much more sensitive for the detection of dust impacts than thin wire antennas. This proposal attributes a large part of the signal on the antenna to a disruption of the photoelectron cloud around the antenna, and the signal is larger on thick antennas because there are more photoelectrons. However, comparison of thick and thin wire antennas on the Wind spacecraft has shown that thick antennas are somewhat more sensitive than thin wire antennas, but the difference is not as great as first supposed. Here an attempt is made to understand the quantitative difference between the responses of thick and thin antennas. It is found that a recent conjecture by the present author that the necessary increase in angular momentum for photoelectrons to avoid returning to a thick antenna would compensate for the larger number of photoelectrons is not correct. It is shown, however, that there is a significant difference in sensitivity between thin and thick antennas. An accurate calculation of the antenna sensitivities is not done here, as it depends on a number of factors, including a large difference in electric field around the antennas. Nevertheless, the photoelectron disruption mechanism is an important advance in understanding the coupling of dust impacts to antennas.
Implications of MAVEN's planetographic coordinate system for comparisons to other recent Mars orbital missions
Authors: Withers Paul , Jakosky B. M.
Published: January 2017

The Mars Atmosphere and Volatile EvolutioN (MAVEN) mission uses a planetographic coordinate system to report altitude, latitude, and longitude on Mars. By contrast, Mars Global Surveyor, Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter generally used a planetocentric coordinate system. These two coordinate systems are different: latitudes differ by up to 0.34° and altitudes differ by up to 2 km. These differences are large enough to affect the scientific results of comparisons between MAVEN and other orbital data sets. This is illustrated with three examples. (a) Comparisons of neutral density inferred from ionospheric peak altitude could contain errors of 25%. (b) Comparisons of mesopause altitude found from ultraviolet stellar occultations could contain errors of 2 km. (c) Comparisons of zonal variations in thermospheric density found from accelerometer observations could contain errors of 12%. Scientists who compare MAVEN data to other data sets, or to models derived from other data sets, should be aware of these differences in the coordinate systems and make appropriate adjustments.
Acidic weathering of basalt and basaltic glass: 1. Near‐infrared spectra, thermal infrared spectra, and implications for Mars
Authors: Horgan Briony H. N. , Smith Rebecca J. , Cloutis Edward A. , Mann Paul , Christensen Philip R.
Published: January 2017

Acid‐leached rinds and coatings occur in volcanic environments on Earth and have been identified using orbital spectroscopy on Mars, but their development is poorly understood. We simulated long‐term open‐system acidic weathering in a laboratory by repeatedly rinsing and submerging crystalline and glassy basalts in pH ~ 1 and pH ~ 3 acidic solutions for 213 days and compared their visible/near‐infrared (0.3–2.5 µm) and thermal infrared (5–50 µm) spectral characteristics to their microscopic physical and chemical properties from scanning electron microscopy (SEM). We find that while alteration at moderately low pH (~3) can produce mineral precipitates from solution, it has very little spectral or physical effect on the underlying parent material. In contrast, alteration at very low pH (~1) results in clear silica spectral signatures for all crystalline samples while glasses exhibit strong blue concave‐up near‐infrared slopes. SEM indicates that these spectral differences correspond to different modes of alteration. In glass, alteration occurs only at the surface and produces a silica‐enriched leached rind, while in more crystalline samples, alteration penetrates the interior to cause dissolution and replacement by silica. We confirm that glass is more stable than crystalline basalt under long‐term acidic leaching, suggesting that glass could be enriched and common in terrains on Mars that have been exposed to acidic weathering. Leached glasses are consistent with both OMEGA and Thermal Emission Spectrometer (TES) spectra of the Martian northern lowlands and may contribute to the high‐silica phases detected globally in TES Surface Type 2. Thus, both glass‐rich deposits and acidic weathering may have been widespread on Mars.
Gypsum veins in Triassic Moenkopi mudrocks of southern Utah: Analogs to calcium sulfate veins on Mars
Authors: Young B. W. , Chan M. A.
Published: January 2017

Well‐exposed gypsum veins in the Triassic Moenkopi formation in southern Utah, USA, are similar to veins at Endeavour and Gale Craters on Mars. Both Moenkopi and Mars veins are hydrated calcium sulfate, have fibrous textures, and crosscut other diagenetic features. Moenkopi veins are stratigraphically localized with strontium and sulfur isotope ratios similar to primary Moenkopi sulfate beds and are thus interpreted to be sourced from within the unit. Endeavour veins seem to be distributed by lithology and may have a local source. Gale veins cut across multiple lithologies and appear to be sourced from another stratigraphic interval. Evaluation of vein network geometries indicates that horizontal Moenkopi veins are longer and thicker than vertical veins. Moenkopi veins are also generally oriented with the modern stress field, so are interpreted to have formed in the latest stages of exhumation. Endeavour veins appear to be generally vertical and oriented parallel to the margins of Cape York and are interpreted to have formed in response to topographic collapse of the crater rim. Gale horizontal veins appear to be slightly more continuous than vertical veins and may have formed during exhumation. Abrupt changes in orientation, complex crosscutting relationships, and fibrous (antitaxial) texture in Moenkopi and Mars veins suggest emplacement via hydraulic fracture at low temperatures. Moenkopi and Mars veins are interpreted as late‐stage diagenetic features that have experienced little alteration since emplacement. Moenkopi veins are useful terrestrial analogs for Mars veins because vein geometry, texture, and chemistry record information about crustal deformation and vein emplacement.
Evaluating waterpoint sustainability and access implications of revenue collection approaches in ruralKenya
Authors: Foster T. , Hope R.
Published: January 2017

Water policies in many sub‐Saharan African countries stipulate that rural communities are responsible for self‐financing their waterpoint's operation and maintenance. In the absence of policy consensus or evidence on optimal payment models, rural communities adopt a diversity of approaches to revenue collection. This study empirically assesses waterpoint sustainability and access outcomes associated with different revenue collection approaches on the south coast of Kenya. The analysis draws on a unique data set comprising financial records spanning 27 years and 100 communities, operational performance indicators for 200 waterpoints, and water source choices for more than 2000 households. Results suggest communities collecting pay‐as‐you‐fetch fees on a volumetric basis generate higher levels of revenue and experience better operational performance than communities charging flat fees. In both cases, financial flows mirror seasonal rainfall peaks and troughs. These outcomes are tempered by evidence that households are more likely to opt for an unimproved drinking water source when a pay‐as‐you‐fetch system is in place. The findings illuminate a possible tension between financial sustainability and universal access. If the Sustainable Development Goal of “safe water for all” is to become a reality, policymakers and practitioners will need to address this issue and ensure rural water services are both sustainable and inclusive.
Facile Doping and Work‐Function Modification of Few‐Layer Graphene Using Molecular Oxidants and Reductants
Authors: Mansour Ahmed E. , Said Marcel M. , Dey Sukumar , Hu Hanlin , Zhang Siyuan , Munir Rahim , Zhang Yadong , Moudgil Karttikay , Barlow Stephen , Marder Seth R. , Amassian Aram
Published: January 2017

Doping of graphene is a viable route toward enhancing its electrical conductivity and modulating its work function for a wide range of technological applications. In this work, the authors demonstrate facile, solution‐based, noncovalent surface doping of few‐layer graphene (FLG) using a series of molecular metal‐organic and organic species of varying n‐ and p‐type doping strengths. In doing so, the authors tune the electronic, optical, and transport properties of FLG. The authors modulate the work function of graphene over a range of 2.4 eV (from 2.9 to 5.3 eV)—unprecedented for solution‐based doping—via surface electron transfer. A substantial improvement of the conductivity of FLG is attributed to increasing carrier density, slightly offset by a minor reduction of mobility via Coulomb scattering. The mobility of single layer graphene has been reported to decrease significantly more via similar surface doping than FLG, which has the ability to screen buried layers. The dopant dosage influences the properties of FLG and reveals an optimal window of dopant coverage for the best transport properties, wherein dopant molecules aggregate into small and isolated clusters on the surface of FLG. This study shows how soluble molecular dopants can easily and effectively tune the work function and improve the optoelectronic properties of graphene.
Analyzing the Carrier Mobility in Transition‐Metal Dichalcogenide MoS2 Field‐Effect Transistors
Authors: Yu Zhihao , Ong Zhun‐Yong , Li Songlin , Xu Jian‐Bin , Zhang Gang , Zhang Yong‐Wei , Shi Yi , Wang Xinran
Published: January 2017

Transition‐metal dichalcogenides (TMDCs) are an important class of two‐dimensional (2D) layered materials for electronic and optoelectronic applications, due to their ultimate body thickness, sizable and tunable bandgap, and decent theoretical room‐temperature mobility. So far, however, all TMDCs show much lower mobility experimentally because of the collective effects by foreign impurities, which has become one of the most important limitations for their device applications. Here, taking MoS2 as an example, the key factors that bring down the mobility in TMDC transistors, including phonons, charged impurities, defects, and charge traps, are reviewed. A theoretical model that quantitatively captures the scaling of mobility with temperature, carrier density, and thickness is introduced. By fitting the available mobility data from literature over the past few years, one obtains the density of impurities and traps for a wide range of transistor structures. It shows that interface engineering can effectively reduce the impurities, leading to improved device performances. For few‐layer TMDCs, the lopsided carrier distribution is analytically modeled to elucidate the experimental increase of mobility with the number of layers. From our analysis, it is clear that the charge transport in TMDC samples is a very complex problem that must be handled carefully.
Toroidal Protein Adaptor Assembles Ferrimagnetic Nanoparticle Fibers with Constructive Magnetic Coupling
Authors: Pham Tuan Anh , Schreiber Andreas , Schiller Stefan M. , Cölfen Helmut
Published: January 2017

Inspired by nature, the synthesis of biohybrid nanocomposites containing inorganic nanoparticles (NPs) and biopolymers such as DNA and peptides as templates offers great potential for a wide range of applications. Using selective recognition schemes of 3D protein spaces for the assembly of magnetic nanocrystals is a challenge with great promise in the field of biomedicine and magnetic data storage. Here we apply the toroidal protein Hcp1 as an interparticle connector for the directed molecular assembly and ferrimagnetic coupling of biohybrid cobalt ferrite NP wires. The resulting biohybrid NP composites show bundles of nanofibers ranging from nano‐ to the microscale in length verified by TEM, EDX analysis and focused ion beam cut. Their magnetic characterization reveals an increase of the coercive field (+12%) reaching values of high‐end Nd2Fe14B bulk magnets, enhanced saturation (+28%) and remanence magnetization (+38%) at 2 K compared to NPs lacking the protein connector. Thus, the combination of the nanoscale alignment of magnetic NPs with the molecular precision of the protein connectors leads to constructive addition of the magnetization reversal energy. This approach can be used to control magnetic properties for the design of materials with enhanced coercivity applicable for magnetic data storage, hyperthermia and theranostics.