bluuebunny/crossref_metadata_2025 huggingface dataset:
Dielectric tunability of vertically aligned ferroelectric-metal oxide nanocomposite films controlled by out-of-plane misfit strain
Authors: Wu Huaping , Ma Xuefu , Zhang Zheng , Zhu Jun , Wang Jie , Chai Guozhong
Published: April 2016

A nonlinear thermodynamic model based on the vertically aligned nanocomposite (VAN) thin films of ferroelectric-metal oxide system has been developed to investigate the physical properties of the epitaxial Ba0.6Sr0.4TiO3 (BST) films containing vertical Sm2O3 (SmO) nanopillar arrays on the SrTiO3 substrate. The phase diagrams of out-of-plane lattice mismatch vs. volume fraction of SmO are calculated by minimizing the total free energy. It is found that the phase transformation and dielectric response of BST-SmO VAN systems are extremely dependent on the in-plane misfit strain, the out-of-plane lattice mismatch, the volume fraction of SmO phase, and the external electric field applied to the nanocomposite films at room temperature. In particular, the BST-SmO VAN systems exhibit higher dielectric properties than pure BST films. Giant dielectric response and maximum tunability are obtained near the lattice mismatch where the phase transition occurs. Under the in-plane misfit strain of umf=0.3% and the out-of-plane lattice mismatch of u3=0.002, the dielectric tunability can be dramatically enhanced to 90% with the increase of SmO volume fraction, which is well consistent with previous experimental results. This work represents an approach to further understand the dependence of physical properties on the lattice mismatch (in-plane and out-of-plane) and volume fraction, and to manipulate or optimize functionalities in the nanocomposite oxide thin films.
The double exponential sinc collocation method for singular Sturm-Liouville problems
Authors: Gaudreau P. , Slevinsky R. , Safouhi H.
Published: April 2016

Sturm-Liouville problems are abundant in the numerical treatment of scientific and engineering problems. In the present contribution, we present an efficient and highly accurate method for computing eigenvalues of singular Sturm-Liouville boundary value problems. The proposed method uses the double exponential formula coupled with sinc collocation method. This method produces a symmetric positive-definite generalized eigenvalue system and has exponential convergence rate. Numerical examples are presented and comparisons with single exponential sinc collocation method clearly illustrate the advantage of using the double exponential formula.
Level crossings, excess times, and transient plasma–wall interactions in fusion plasmas
Authors: Theodorsen A. , Garcia O. E.
Published: April 2016

Based on a stochastic model for intermittent fluctuations in the boundary region of magnetically confined plasmas, an expression for the level crossing rate is derived from the joint distribution of the process and its derivative. From this the average time spent by the process above a certain threshold level is obtained. This provides novel predictions of plasma–wall interactions due to transient transport events associated with a radial motion of blob-like structures in the scrape-off layer.
Electrical limit of silver nanowire electrodes: Direct measurement of the nanowire junction resistance
Authors: Selzer Franz , Floresca Carlo , Kneppe David , Bormann Ludwig , Sachse Christoph , Weiß Nelli , Eychmüller Alexander , Amassian Aram , Müller-Meskamp Lars , Leo Karl
Published: April 2016

We measure basic network parameters of silver nanowire (AgNW) networks commonly used as transparent conducting electrodes in organic optoelectronic devices. By means of four point probing with nanoprobes, the wire-to-wire junction resistance and the resistance of single nanowires are measured. The resistance RNW of a single nanowire shows a value of RNW=(4.96±0.18) Ω/μm. The junction resistance RJ differs for annealed and non-annealed NW networks, exhibiting values of RJ=(25.2±1.9) Ω (annealed) and RJ=(529±239) Ω (non-annealed), respectively. Our simulation achieves a good agreement between the measured network parameters and the sheet resistance RS of the entire network. Extrapolating RJ to zero, our study show that we are close to the electrical limit of the conductivity of our AgNW system: We obtain a possible RS reduction by only ≈20% (common RS≈10 Ω/sq). Therefore, we expect further performance improvements in AgNW systems mainly by increasing NW length or by utilizing novel network geometries.
Effect of β-carotene supplementation on the expression of lipid metabolism-related genes and the deposition of back fat in beef cattle
Authors: Jin Q. , Zhao H. B. , Liu X. M. , Wan F. C. , Liu Y. F. , Cheng H. J. , You W. , Liu G. F. , Tan X. W.
Published: April 2016

To evaluate the effects of β-carotene (βC) supplementation on lipid metabolism in the back fat of beef cattle, 120 continental crossbred (Simmental × local Luxi yellow cattle) steers were selected randomly from feedlots and allotted to four groups. Each steer was supplemented with 0, 600, 1200, or 1800 mg/day of βC for 90 days, and then received no βC for 60 days (depletion period). The βC levels significantly increased in steers supplemented with βC (P < 0.01), and then decreased to the control level by Day 150. Back fat thickness decreased slightly with increasing βC supplementation, and significantly differed among groups after supplementation ceased (P < 0.01 on Day 120, P < 0.05 on Day 150). Significant regression relationships between βC supplement level and both βC content in back fat tissue on Day 90 and back fat thickness on Days 90, 120, and 150 were established (P < 0.01). No significant differences in the dry matter intake or average daily gain were detected, but higher net meat percentages were observed in the 1200 and 1800 mg/day βC-supplemented groups compared with the control (P < 0.05). The mRNA expression of two fat synthesis-related genes, acetyl-CoA carboxylase and fatty acid synthase, were downregulated during the supplementation period, but upregulated during the next 60 days when the steers received no βC supplementation. In contrast, the expression of two fat hydrolysis-related genes, hormone-sensitive lipase and adipose triglyceride lipase, were upregulated during the supplementation period and downregulated in the subsequent 60 days. The results showed that βC supplementation suppresses back fat deposition in beef cattle by inhibiting fat synthesis and enhancing fat hydrolysis.
Photoinitiated Synthesis of Sulfides in Water
Authors: Rodriguez Sergio A. , Mena Leandro D. , Baumgartner Maria T.
Published: April 2016

Herein, we report a synthetic route to obtain aryl sulfides using inexpensive and non-toxic reactants and water as solvent, that avoids the use of catalysts or heating. The photoinduced reaction between soluble substrates and a series of thiols in alkaline aqueous medium produces the corresponding sulfides in moderate to good yields.
Data assimilation of dead fuel moisture observations from remote automated weather stations
Authors: Vejmelka Martin , Kochanski Adam K. , Mandel Jan
Published: April 2016

Fuel moisture has a major influence on the behaviour of wildland fires and is an important underlying factor in fire risk assessment. We propose a method to assimilate dead fuel moisture content (FMC) observations from remote automated weather stations (RAWS) into a time lag fuel moisture model. RAWS are spatially sparse and a mechanism is needed to estimate fuel moisture content at locations potentially distant from observational stations. This is arranged using a trend surface model (TSM), which allows us to account for the effects of topography and atmospheric state on the spatial variability of FMC. At each location of interest, the TSM provides a pseudo-observation, which is assimilated via Kalman filtering. The method is tested with the time lag fuel moisture model in the coupled weather-fire code WRF–SFIRE on 10-h FMC observations from Colorado RAWS in 2013. Using leave-one-out testing we show that the TSM compares favourably with inverse squared distance interpolation as used in the Wildland Fire Assessment System. Finally, we demonstrate that the data assimilation method is able to improve on FMC estimates in unobserved fuel classes.
Biodegradable antigen-associated PLG nanoparticles tolerize Th2-mediated allergic airway inflammation pre- and postsensitization
Authors: Smarr Charles B. , Yap Woon Teck , Neef Tobias P. , Pearson Ryan M. , Hunter Zoe N. , Ifergan Igal , Getts Daniel R. , Bryce Paul J. , Shea Lonnie D. , Miller Stephen D.
Published: April 2016

Significance

Allergic diseases are characterized by inappropriate inflammatory responses to benign environmental antigens (Ags). Primary clinical approaches to allergic disease consist of symptom control or administration of soluble Ag to skew the immune response to alternate phenotypes or induce immune tolerance. However, such approaches carry a significant risk of adverse events and require a long treatment course to achieve efficacy. In this paper, we describe the use of i.v.-administered nanoparticles as carriers of whole-protein Ag to induce tolerance safely and effectively in the absence of nonspecific immunosuppression for the prevention and treatment of a mouse model of allergic asthma.
Cu isotopes in marine black shales record the Great Oxidation Event
Authors: Chi Fru Ernest , Rodríguez Nathalie P. , Partin Camille A. , Lalonde Stefan V. , Andersson Per , Weiss Dominik J. , El Albani Abderrazak , Rodushkin Ilia , Konhauser Kurt O.
Published: April 2016

Significance

Redox-sensitive transition metals and their isotopes provide some of the best lines of evidence for reconstructing early Earth’s oxygenation history, including permanent atmospheric oxygenation following the Great Oxidation Event (GOE), ∼2.45−2.32 Ga. We show a shift from dominantly negative to permanently positive copper isotope compositions in black shales spanning ∼2.66−2.08 Ga. We interpret the transition in marine δ
65
Cu values as reflecting some combination of waning banded iron formation deposition (which removes heavy Cu) and increased oxidative delivery of Cu from continental sulfides (which supplies heavy Cu). Both processes are ultimately related to increased oxidative weathering and a progressive increase in sulfate and sulfide availability accompanying the GOE. Our results provide insights into copper cycling and bioavailability coupled to Earth’s oxygenation history.
Low-latitude arc–continent collision as a driver for global cooling
Authors: Jagoutz Oliver , Macdonald Francis A. , Royden Leigh
Published: April 2016

Significance

This manuscript provides a mechanism for triggering cooling events following the Cretaceous Thermal Maximum and the Early Eocene Climate optimum that ultimately resulted in the Cenozoic glaciation. We present a quantitative model of changes in CO2sources and sinks during the closure of the Neo-Tethys Ocean. Our results suggest that long-term cooling was predominantly due to obduction of highly weatherable mafic and ultramafic Ca- and Mg-rich rocks (ophiolites) in the wet tropics. Our model accounts for both the two episodes of cooling and also the partial recovery in temperatures between ∼70 and 50 Ma.
Clusters of circulating tumor cells traverse capillary-sized vessels
Authors: Au Sam H. , Storey Brian D. , Moore John C. , Tang Qin , Chen Yeng-Long , Javaid Sarah , Sarioglu A. Fatih , Sullivan Ryan , Madden Marissa W. , O’Keefe Ryan , Haber Daniel A. , Maheswaran Shyamala , Langenau David M. , Stott Shannon L. , Toner Mehmet
Published: April 2016

Significance

Metastasis is responsible for 90% of cancer-related deaths and is driven by tumor cells circulating in blood. However, it is believed that only individual tumor cells can reach distant organs because multicellular clusters are too large to pass through narrow capillaries. Here, we collected evidence by examining clusters in microscale devices, computational simulations, and animals, which suggest that this assumption is incorrect, and that clusters may transit through capillaries by unfolding into single-file chains. This previously unidentified cell behavior may explain why previous experiments reported that clusters were more efficient at seeding metastases than equal numbers of single tumor cells, and has led to a strategy that, if applied clinically, may reduce the incidence of metastasis in patients.
Benefit of transferred mutations is better predicted by the fitness of recipients than by their ecological or genetic relatedness
Authors: Wang Yinhua , Diaz Arenas Carolina , Stoebel Daniel M. , Flynn Kenneth , Knapp Ethan , Dillon Marcus M. , Wünsche Andrea , Hatcher Philip J. , Moore Francisco B.-G. , Cooper Vaughn S. , Cooper Tim F.
Published: April 2016

Significance

The fitness effect of many mutations depends on the genotype of the individual in which they occur. Are these dependencies predictable? Do dependencies build on existing variation between individuals to promote divergence, or do they act to favor genetic cohesion? We examine these questions by measuring the fitness effect of mutations that conferred a benefit in a laboratory-evolved population when transferred into genetically and phenotypically diverse natural isolates of the same species. We found that fitness effects were predicted by the fitness of the strain to which they were added but not by the genetic or ecological relationship of the recipient strains. This pattern extends findings that the current fitness of strain is a major predictor of its ability to adapt.
Photonic topological insulator with broken time-reversal symmetry
Authors: He Cheng , Sun Xiao-Chen , Liu Xiao-Ping , Lu Ming-Hui , Chen Yulin , Feng Liang , Chen Yan-Feng
Published: April 2016

Significance

Topological insulators are first discovered in electronic systems. A key factor is the Kramers doublet for the spin-1/2 electrons under fermionic time-reversal symmetry

T
f
2

=
−
1

. Unlike electrons, photons are massless bosons with spin-1. Therefore, the Kramers degeneracy theorem cannot readily apply to photons under the bosonic time-reversal symmetry. So far, there has been no coherent physical explanation for the symmetry protection mechanism behind the photonic topological insulator. Here, we design a photonic topological insulator that violates the bosonic time-reversal symmetry but complies with a fermionic-like pseudo time-reversal symmetry. The analyses and results, through comprehensive investigations on the properties of edge states, validate that the topological edge states are, in fact, protected by the fermionic-like pseudo time-reversal symmetry
T

p

(

T
p
2

=
−
1

).
Stable aqueous dispersions of optically and electronically active phosphorene
Authors: Kang Joohoon , Wells Spencer A. , Wood Joshua D. , Lee Jae-Hyeok , Liu Xiaolong , Ryder Christopher R. , Zhu Jian , Guest Jeffrey R. , Husko Chad A. , Hersam Mark C.
Published: April 2016

Significance

Few-layered phosphorene, which is isolated through exfoliation from black phosphorus, has attracted great interest due to its unique electronic and optical properties. Although solution-based exfoliation methods have been developed for black phosphorus, these techniques have thus far used anhydrous organic solvents. This approach minimizes exposure to known oxidizing species, but at the cost of limited exfoliation yield and relatively thick flakes. Here, we overcome these limitations by using stabilizing surfactants in deoxygenated water, which results in phosphorene down to the monolayer limit. The resulting aqueous phosphorene dispersions show layer-dependent photoluminescence and enable high-performance field-effect transistors. Overall, this approach holds promise for the solution-phase production of few-layered phosphorene in emerging large-volume applications including electronics and optoelectronics.
IL-33 ameliorates Alzheimer’s disease-like pathology and cognitive decline
Authors: Fu Amy K. Y. , Hung Kwok-Wang , Yuen Michael Y. F. , Zhou Xiaopu , Mak Deejay S. Y. , Chan Ivy C. W. , Cheung Tom H. , Zhang Baorong , Fu Wing-Yu , Liew Foo Y. , Ip Nancy Y.
Published: April 2016

Significance

Dysfunction of the innate immune system is involved in the pathogenesis of Alzheimer’s disease (AD); however, the pathophysiological mechanisms underlying these dysfunctions are unclear. Here we report that stimulation of IL-33/ST2 signaling rescues memory deficits and reduces the accumulation of β-amyloid in APP/PS1 mice that exhibit select pathologies associated with AD. Although impaired IL-33/ST2 signaling is associated with early progression of AD, IL-33 injection rescues contextual memory deficits and reduces the accumulation of β-amyloid in APP/PS1 mice. IL-33 skews the microglia toward an alternative activation state with enhanced Aβ phagocytic capacity and elevated antiinflammatory gene expression, which results in a decreased proinflammatory response in the brain. Thus, this study suggests that IL-33 can be developed as a new therapeutic intervention for AD.
Durable antitumor responses to CD47 blockade require adaptive immune stimulation
Authors: Sockolosky Jonathan T. , Dougan Michael , Ingram Jessica R. , Ho Chia Chi M. , Kauke Monique J. , Almo Steven C. , Ploegh Hidde L. , Garcia K. Christopher
Published: April 2016

Significance

Therapeutic antitumor antibodies are widely used clinically. CD47 is an antiphagocytic ligand expressed by tumors that binds the inhibitory receptor signal regulatory protein alpha (SIRPα) on phagocytic cells. Interruption of CD47–SIRPα interactions in immunodeficient mice bearing human tumors enhances therapeutic antitumor antibody responses by promoting phagocytosis of antibody-bound tumor cells. Here, we use a novel anti-CD47 single domain antibody, derived from an alpaca, in an immunocompetent mouse model of melanoma and find that, in contrast to immunodeficient models, CD47 blockade alone is insufficient to enhance the effects of antimelanoma antibodies. However, when combined with blockade of programmed death-ligand 1 (PD-L1), an immune receptor that inhibits antitumor T cell responses, we find synergistic activity, suggesting a role for both innate and adaptive inhibitory pathways in the response to therapeutic antibodies.
Predation by Northern Pikeminnow and Tiger Muskellunge on Juvenile Salmonids in a High‐Head Reservoir: Implications for Anadromous Fish Reintroductions
Authors: Sorel Mark H. , Hansen Adam G. , Connelly Kristin A. , Wilson Andrew C. , Lowery Erin D. , Beauchamp David A.
Published: April 2016

The feasibility of reintroducing anadromous salmonids into reservoirs above high‐head dams is affected by the suitability of the reservoir habitat for rearing and the interactions of the resident fish with introduced fish. We evaluated the predation risk to anadromous salmonids considered for reintroduction in Merwin Reservoir on the North Fork Lewis River in Washington State for two reservoir use‐scenarios: year‐round rearing and smolt migration. We characterized the role of the primary predators, Northern Pikeminnow Ptychocheilus oregonensis and tiger muskellunge (Northern Pike Esox lucius × Muskellunge E. masquinongy), by using stable isotopes and stomach content analysis, quantified seasonal, per capita predation using bioenergetics modeling, and evaluated the size and age structures of the populations. We then combined these inputs to estimate predation rates of size‐structured population units. Northern Pikeminnow of FL ≥ 300 mm were highly cannibalistic and exhibited modest, seasonal, per capita predation on salmonids, but they were disproportionately much less abundant than smaller, less piscivorous, conspecifics. The annual predation on kokanee Oncorhynchus nerka (in biomass) by a size‐structured unit of 1,000 Northern Pikeminnow having a FL ≥ 300 mm was analogous to 16,000–40,000 age‐0 spring Chinook Salmon O. tshawytscha rearing year‐round, or 400–1,000 age‐1 smolts migrating April–June. The per capita consumption of salmonids by Northern Pikeminnow having a FL ≥ 200 mm was relatively low, due in large part to spatial segregation during the summer and the skewed size distribution of the predator population. Tiger muskellunge fed heavily on Northern Pikeminnow, other nonsalmonids, and minimally on salmonids. In addition to cannibalism within the Northern Pikeminnow population, predation by tiger muskellunge likely contributed to the low recruitment of larger (more piscivorous) Northern Pikeminnow, thereby decreasing the risk of predation to salmonids. This study highlights the importance of evaluating trophic interactions within reservoirs slated for reintroduction with anadromous salmonids, as they can be functional migration corridors and may offer profitable juvenile‐rearing habitats despite hosting abundant predator populations.

Received September 3, 2015; accepted December 7, 2015 Published online April 19, 2016
Factors Influencing Stream Fish Species Composition and Functional Properties at Multiple Spatial Scales in the Sand Hills of the Southeastern United States
Authors: Paller Michael H. , Prusha Blair A. , Fletcher Dean E. , Kosnicki Ely , Sefick Stephen A. , Jarrell Miller S. , Sterrett Sean C. , Grosse Andrew M. , Tuberville Tracey D. , Feminella Jack W.
Published: April 2016

An understanding of how fish communities differ among river basin, watershed, and stream reach spatial scales and the factors that influence these differences can help in the design of effective conservation programs and the development of reference models that appropriately represent biota under relatively undisturbed conditions. We assessed the heterogeneity among fish assemblages in first‐ to fourth‐order stream sites from four river basins (Savannah, Chattahoochee, Cape Fear, and Pee Dee rivers) within the Sand Hills ecoregion of the southeastern USA and compared it with the heterogeneity associated with watershed and stream reach spatial scales. Fifty‐five species of fish representing 15 families were collected by electrofishing, with the most speciose families being Cyprinidae, Centrarchidae, Percidae, Ictaluridae, and Catostomidae. Constrained ordination identified clearly demarcated species assemblages among river basins as well as subbasin environmental variables that affected fish species composition; the amounts of variance attributable to basin, watershed, and stream reach spatial scales were roughly equivalent. Prominent differences occurred between Gulf of Mexico coast and Atlantic coast river basins, but differences among Atlantic coast basins were also apparent. Key variables at the watershed scale included watershed size, relief, extent of anthropogenic disturbance, and forest cover; key variables at the stream reach scale included instream habitat quality, proximity to a larger stream, and stream width. Fish assemblage collective and functional properties were more strongly influenced by variables acting at watershed and stream reach spatial scales than by differences among basins. Species richness peaked at intermediate levels of habitat quality as a likely result of biotic homogenization, indicating that the least disturbed sites within the region do not necessarily possess the highest species richness. Failure to consider this may lead to the overrating of moderately disturbed sites and the underrating of minimally disturbed sites, thus contributing to false conclusions about fish assemblage integrity.

Received September 15, 2015; accepted December 15, 2015 Published online April 19, 2016
Dialogue and the development of ideas in the political and social sciences: from critical realism to problem-solving via Colin Hay and the rejection of the epistemic fallacy
Authors: Cruickshank Justin
Published: April 2016

Colin Hay’s extensive work on politics helps illustrate that ideas can have significant traction of their own which inhibits change. Therefore, accounts of conceptual development in the political and social sciences should examine the possibility of slow dialogue, as a form of communication hospitable to innovation. For critical realism, justified explanations must avoid the ‘epistemic fallacy’ of conflating ontological questions about what reality is with epistemological questions about how we know reality; it prefers basing explanations on an ontology of structure and agency. I argue, using Popper and Lakatos’s problem-solving epistemology, that the critical-realist construction of the epistemic fallacy is untenable, and that attempts at justification entail what I call ‘speedy’ dialogue, with putatively ‘unjustified’ positions being simply rejected; unlike the slow dialogue that problem-solving demands. I also use Hay to show how problem-solving needs to include ontological references, once they are separated from the attempt to justify ideas.
Conical limit points and the Cannon-Thurston map
Authors: Jeon Woojin , Kapovich Ilya , Leininger Christopher , Ohshika Ken’ichi
Published: April 2016

Let

G
G

be a non-elementary word-hyperbolic group acting as a convergence group on a compact metrizable space

Z
Z

so that there exists a continuous

G
G

-equivariant map

i
:
∂
G
→
Z

i:\partial G\to Z

, which we call a Cannon-Thurston map. We obtain two characterizations (a dynamical one and a geometric one) of conical limit points in

Z
Z

in terms of their pre-images under the Cannon-Thurston map

i
i

. As an application we prove, under the extra assumption that the action of

G
G

on

Z
Z

has no accidental parabolics, that if the map

i
i

is not injective, then there exists a non-conical limit point

z
∈
Z

z\in Z

with

|

i

−
1

(
z
)

|

=
1

|i^{-1}(z)|=1

. This result applies to most natural contexts where the Cannon-Thurston map is known to exist, including subgroups of word-hyperbolic groups and Kleinian representations of surface groups. As another application, we prove that if

G
G

is a non-elementary torsion-free word-hyperbolic group, then there exists

x
∈
∂
G

x\in \partial G

such that

x
x

is not a “controlled concentration point” for the action of

G
G

on

∂
G

\partial G

.
A short proof of the Dimension Conjecture for real hypersurfaces in ℂ²
Authors: Isaev Alexander , Kruglikov Boris
Published: April 2016

Recently, I. Kossovskiy and R. Shafikov settled the so-called Dimension Conjecture, which characterizes spherical hypersurfaces in

C

2

\mathbb {C}^2

via the dimension of the algebra of infinitesimal CR-automorphisms. In this note, we propose a short argument for obtaining their result.
Coefficients of McKay-Thompson series and distributions of the moonshine module
Authors: Larson Hannah
Published: April 2016

In a recent paper, Duncan, Griffin and Ono provide exact formulas for the coefficients of McKay-Thompson series and use them to find asymptotic expressions for the distribution of irreducible representations in the moonshine module

V
♮

=

⨁
n

V
n
♮

V^\natural = \bigoplus _n V_n^\natural

. Their results show that as

n
n

tends to infinity,

V
n
♮

V_n^\natural

is dominated by direct sums of copies of the regular representation. That is, if we view

V
n
♮

V_n^\natural

as a module over the group ring

Z

[

M

]

\mathbb {Z}[\mathbb {M}]

, the free part dominates. A natural problem, posed at the end of the aforementioned paper, is to characterize the distribution of irreducible representations in the non-free part. Here, we study asymptotic formulas for the coefficients of McKay-Thompson series to answer this question. We arrive at an ordering of the series by the magnitude of their coefficients, which corresponds to various contributions to the distribution. In particular, we show how the asymptotic distribution of the non-free part is dictated by the column for conjugacy class 2A in the monster’s character table. We find analogous results for the other monster modules

V

(
−
m
)

V^{(-m)}

and

W
♮

W^\natural

studied by Duncan, Griffin, and Ono.
Conceptualizing Medieval Book Collections
Authors: Hinton Thomas
Published: April 2016

This article argues for a conceptual distinction between the practices and ideologies of institutional learning on the one hand (whose natural vehicle was Latin, the language of formal education) and those of a vernacular written culture that both challenges and models itself on the former. The garden, used as a figure for the ideal library by Richard de Fournival in the thirteenth century, creates order through the institutionalization of knowledge and the exclusion of undesirable elements. By contrast, the forest is deployed by medieval and modern thinkers to embody a wild, unsorted chaos apparently inimical to learning. And yet the forest in medieval literature functions as a margin always in contact with civilization, whose illicit danger is matched by its attractiveness as a space for unplanned encounters and reconfigurations of hierarchy and authority. As I demonstrate, an analogous concern with the potential for book collections to lead readers to unexpected discoveries is a recurrent theme of vernacular authors from Benoît de Sainte-Maure to Chaucer. This conceptual approach to the function and cultural value of medieval libraries offers a supplementary perspective to more traditional ‘book archaeology’, one which may be especially fruitful for making sense of the often fragmentary and vague records of private ownership.
A Model for Catalyzing Educational and Clinical Transformation in Primary Care: Outcomes From a Partnership Among Family Medicine, Internal Medicine, and Pediatrics
Authors: Eiff M. Patrice , Green Larry A. , Holmboe Eric , McDonald Furman S. , Klink Kathleen , Smith David Gary , Carraccio Carol , Harding Rose , Dexter Eve , Marino Miguel , Jones Sam , Caverzagie Kelly , Mustapha Mumtaz , Carney Patricia A.
Published: April 2016

Purpose

To report findings from a national effort initiated by three primary care certifying boards to catalyze change in primary care training.

Method

In this mixed-method pilot study (2012–2014), 36 faculty in 12 primary care residencies (family medicine, internal medicine, pediatrics) from four institutions participated in a professional development program designed to prepare faculty to accelerate change in primary care residency training by uniting them in a common mission to create effective ambulatory clinical learning environments. Surveys administered at baseline and 12 months after initial training measured changes in faculty members’ confidence and skills, continuity clinics, and residency training programs. Feasibility evaluation involved assessing participation. The authors compared quantitative data using Wilcoxon signed-rank and Bhapkar tests. Observational field notes underwent narrative analysis.

Results

Most participants attended two in-person training sessions (92% and 72%, respectively). Between baseline and 12 months, faculty members’ confidence in leadership improved significantly for 15/19 (79%) variables assessed; their self-assessed skills improved significantly for 21/22 (95%) competencies. Two medical home domains (“Continuity of Care,” “Support/Care Coordination”) improved significantly (P < .05) between the two time periods. Analyses of qualitative data revealed that interdisciplinary learning communities formed during the program and served to catalyze transformational change.

Conclusions

Results suggest that improvements in faculty perceptions of confidence and skills occurred and that the creation of interdisciplinary learning communities catalyzed transformation. Lengthening the intervention period, engaging other professions involved in training the primary care workforce, and a more discriminating evaluation design are needed to scale this model nationally.
Feedback to Supervisors: Is Anonymity Really So Important?
Authors: Dudek Nancy L. , Dojeiji Suzan , Day Kathleen , Varpio Lara
Published: April 2016

Purpose

Research demonstrates that physicians benefit from regular feedback on their clinical supervision from their trainees. Several features of effective feedback are enabled by nonanonymous processes (i.e., open feedback). However, most resident-to-faculty feedback processes are anonymous given concerns of power differentials and possible reprisals. This exploratory study investigated resident experiences of giving faculty open feedback, advantages, and disadvantages.

Method

Between January and August 2014, nine graduates of a Canadian Physiatry residency program that uses open resident-to-faculty feedback participated in semistructured interviews in which they described their experiences of this system. Three members of the research team analyzed transcripts for emergent themes using conventional content analysis. In June 2014, semistructured group interviews were held with six residents who were actively enrolled in the program as a member-checking activity. Themes were refined on the basis of these data.

Results

Advantages of the open feedback system included giving timely feedback that was acted upon (thus enhancing residents’ educational experiences), and improved ability to receive feedback (thanks to observing modeled behavior). Although some disadvantages were noted, they were often speculative (e.g., “I think others might have felt …”) and were described as outweighed by advantages. Participants emphasized the program’s “feedback culture” as an open feedback enabler.

Conclusions

The relationship between the feedback giver and recipient has been described as influencing the uptake of feedback. Findings suggest that nonanonymous practices can enable a positive relationship in resident-to-faculty feedback. The benefits of an open system for resident-to-faculty feedback can be reaped if a “feedback culture” exists.
Focusing on the Formative: Building an Assessment System Aimed at Student Growth and Development
Authors: Konopasek Lyuba , Norcini John , Krupat Edward
Published: April 2016

This Perspective addresses the need for an integrated system of formative and summative assessment in undergraduate medical education with a focus on the formative. While acknowledging the importance of summative assessment, which asks whether trainees have met criteria for progression, the authors propose that a formatively focused assessment system can best accomplish a central task of competency-based medical education: transmitting feedback to learners in a format and a manner that will help them to improve, develop, and grow. Formative assessment should not be seen as a set of singular events but, rather, as a process that is organized and integrated over time, much like the cycle of quality improvement in medicine. To justify this position, the authors discuss its conceptual underpinnings and rationale, including the need to prepare learners for the formatively focused assessment system of graduate medical education. Next, the authors identify assessment strategies that could be employed, as well as the characteristics of an institutional culture and the learner–teacher relationship necessary for a learner-centered, improvement-focused assessment system to succeed. Finally, an infrastructure for such a system is proposed. This consists of a foundation of well-articulated and disseminated milestones for achievement and four pillars: faculty development, learner development, longitudinal academic advising and coaching, and documentation of developing competence. The authors conclude by suggesting that the guidelines proposed are analogous to the principles of continuity and coordination of care, so much valued in the world of medicine yet often overlooked in the world of education.
Translating Research for Health Policy Decisions: Is It Time for Researchers to Join Social Media?
Authors: Meisel Zachary F. , Gollust Sarah E. , Grande David
Published: April 2016

Identifying effective strategies to translate research evidence to policy is a national priority and a priority of the health policy research community. Multiple channels exist to disseminate, translate, and communicate research evidence. Some thought leaders have specifically advocated for researchers to play a direct role in research dissemination, particularly through social media. However, this view remains controversial. This Commentary explores the current state of and future opportunities and barriers for alternative avenues of policy-relevant research dissemination. The authors identify four intersecting realities influencing the manner in which the health research community views and adopts various approaches to research translation: (1) persistent gaps in evidence translation and knowledge transfer, particularly in the realm of health policy; (2) public demand for scholars to embrace new modes of research dissemination; (3) the rapid growth and reach of social media to disseminate information; and (4) skepticism and confusion within the academic community about how best to use social media to disseminate policy-relevant research. They conclude that while scholars will need to be engaged in evidence translation to inform health policy, they may be best served by connecting with trusted intermediaries and knowledge brokers to promote efficient use of the best available evidence to answer the most timely policy questions. Journals and universities may be well positioned to invest in this capacity to curate research evidence and disseminate it using social media and other technologies.
Patients, Nurses, and Physicians Working Together to Develop a Discharge Entrustable Professional Activity Assessment Tool
Authors: Meade Lauren B. , Suddarth Kathleen Heist , Jones Ronald R. , Zaas Aimee K. , Albanese Terry , Yamazaki Kenji , O’Malley Cheryl W.
Published: April 2016

Problem

The Accreditation Council for Graduate Medical Education milestones were written by physicians and thus may not reflect all the behaviors necessary for physicians to optimize their performance as a key member of an interprofessional team.

Approach

From April to May 2013, the authors, Educational Research Outcomes Collaborative leaders, assembled interprofessional team discussion groups, including patients or family members, nurses, physician trainees, physician educators, and other staff (optional), at 11 internal medicine (IM) programs. Led by the site’s principal investigator, the groups generated a list of physician behaviors related to the entrustable professional activity (EPA) of a safe and effective discharge of a patient from the hospital, and prioritized those behaviors.

Outcomes

A total of 182 behaviors were listed, with lists consisting of between 10 and 29 behaviors. Overall, the site principal investigators described all participants as emerging from the activity with a new understanding of the complexity of training physicians for the discharge EPA. The authors batched behaviors into six components of a safe and effective discharge: medication reconciliation, discharge summary, patient/caregiver communication, team communication, active collaboration, and anticipation of posthospital needs. Specific, high-priority behavior examples for each component were identified, and an assessment tool for direct observation was developed for the discharge EPA.

Next Steps

The authors are currently evaluating trainee and educator perceptions of the assessment tool after implementation in 15 IM programs. Additional next steps include developing tools for other EPAs, as well as a broader evaluation of patient outcomes in the era of milestone-based assessment.
A Case Suspended in Time: The Educational Value of Case Reports
Authors: Packer Clifford D. , Katz Rachel B. , Iacopetti Corina L. , Krimmel Jeffrey D. , Singh Mamta K.
Published: April 2016

Although medical case reports have fallen out of favor in the era of the impact factor, there is a long tradition of using case reports for teaching and discovery. Some evidence indicates that writing case reports might improve medical students’ critical thinking and writing skills and help prepare them for future scholarly work. From 2009 through 2015, students participating in the case reporting program at a VA hospital produced 250+ case reports, 35 abstracts, and 15 journal publications. Here, three medical students who published their case reports comment on what they learned from the experience. On the basis of their comments, the authors propose five educational benefits of case reporting: observation and pattern recognition skills; hypothesis-generating skills; understanding of patient-centered care; rhetorical versatility; and use of the case report as a rapidly publishable “mini-thesis,” which could fulfill MD thesis or scholarly concentration requirements. The authors discuss the concept of the case report as a “hybrid narrative” with simultaneous medical and humanistic significance, and its potential use to teach students about their dual roles as engaged listeners and scientists. Finally, the authors consider the limitations and pitfalls of case reports, including patient confidentiality issues, overinterpretation, emphasis on the rare, and low initial publication rates. Case reports allow students to contribute to medical literature, learn useful scholarly skills, and participate in a tradition that links them with past generations of physicians. The authors conclude that the case report can be an effective teaching tool with a broad range of potential educational benefits.
Mechanical Construct Characteristics Predisposing to Non-union After Locked Lateral Plating of Distal Femur Fractures
Authors: Rodriguez Edward K. , Zurakowski David , Herder Lindsay , Hall Amber , Walley Kempland C. , Weaver Mike J. , Appleton Paul T. , Vrahas Mark
Published: April 2016

Objectives:

To identify discrete construct characteristics related to overall construct rigidity that may be independent predictors of nonunion after lateral locked plate (LLP) fixation of distal femur fractures.

Design:

Retrospective case–control study.

Setting:

Three level-1 urban trauma centers.

Patients/Participants:

Two hundred and seventy-one supracondylar femoral fractures treated with LLP at 3 affiliated level 1 urban trauma centers between August 2004 and December 2010.

Methods:

Nonunion was defined as a secondary procedure for poor healing. Construct variables included: (1) combined plate design and material variable, (2) Plate length, (3) # screws proximal to fracture, (4) total screw density (TSD), (5) proximal screw density (PSD), (6) presence of a screw crossing the main fracture, and (7) rigidity score multivariable analysis was performed using logistic regression to identify independent risk factors for nonunion.

Intervention:

LLP fixation.

Main Outcome Measure:

Nonunion.

Results:

Nonunion rate was 13.3% (n = 36). There was a significant association between plate design/material and nonunion with 41% of stainless constructs and 10% of titanium constructs resulting in a nonunion (P < 0.001). Rigidity scores reached significance (P = 0.001) with constructs resulting in a nonunion having higher scores. No significant univariate differences with respect to number of proximal screws, plate length, total screw density, or proximal screw density were observed between healed fractures and those with nonunion. Results of the multivariate analysis confirmed that the primary significant independent predictor of nonunion was plate design/material (odds ratio, 6.8; 95% CI, 2.9–16.1; P < 0.001).

Conclusions:

When treating distal femur fractures with LLP, combined plate design and material variable has a highly significant influence on the risk of nonunion independent of any other construct variable.

Level of Evidence:

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
Staying Out of Trouble Performing Intramedullary Nailing of Forearm Fractures
Authors: Wall Lindley B.
Published: April 2016

Pediatric diaphyseal forearm fractures occur commonly and often require reduction with stabilization. Intramedullary flexible nails provide an effective method for stabilizing and maintaining reduction of these fractures. There are a few specific technical pearls that can be implemented to improve efficiency of nail placement and minimize postoperative complications, such as painful hardware and compartment syndrome.
Age, Pao 2/Fio 2, and Plateau Pressure Score: A Proposal for a Simple Outcome Score in Patients With the Acute Respiratory Distress Syndrome*
Authors: Villar Jesús , Ambrós Alfonso , Soler Juan Alfonso , Martínez Domingo , Ferrando Carlos , Solano Rosario , Mosteiro Fernando , Blanco Jesús , Martín-Rodríguez Carmen , Fernández María del Mar , López Julia , Díaz-Domínguez Francisco J. , Andaluz-Ojeda David , Merayo Eleuterio , Pérez-Méndez Lina , Fernández Rosa Lidia , Kacmarek Robert M.
Published: April 2016

Objectives:

Although there is general agreement on the characteristic features of the acute respiratory distress syndrome, we lack a scoring system that predicts acute respiratory distress syndrome outcome with high probability. Our objective was to develop an outcome score that clinicians could easily calculate at the bedside to predict the risk of death of acute respiratory distress syndrome patients 24 hours after diagnosis.

Design:

A prospective, multicenter, observational, descriptive, and validation study.

Setting:

A network of multidisciplinary ICUs.

Patients:

Six-hundred patients meeting Berlin criteria for moderate and severe acute respiratory distress syndrome enrolled in two independent cohorts treated with lung-protective ventilation.

Interventions:

None.

Measurements and Main Results:

Using individual demographic, pulmonary, and systemic data at 24 hours after acute respiratory distress syndrome diagnosis, we derived our prediction score in 300 acute respiratory distress syndrome patients based on stratification of variable values into tertiles, and validated in an independent cohort of 300 acute respiratory distress syndrome patients. Primary outcome was in-hospital mortality. We found that a 9-point score based on patient’s age, Pao
2/Fio
2 ratio, and plateau pressure at 24 hours after acute respiratory distress syndrome diagnosis was associated with death. Patients with a score greater than 7 had a mortality of 83.3% (relative risk, 5.7; 95% CI, 3.0–11.0), whereas patients with scores less than 5 had a mortality of 14.5% (p < 0.0000001). We confirmed the predictive validity of the score in a validation cohort.

Conclusions:

A simple 9-point score based on the values of age, Pao
2/Fio
2 ratio, and plateau pressure calculated at 24 hours on protective ventilation after acute respiratory distress syndrome diagnosis could be used in real time for rating prognosis of acute respiratory distress syndrome patients with high probability.