bluuebunny/crossref_metadata_2025_split huggingface dataset:
Can formative quizzes predict or improve summative exam performance?*
Authors: Zhang Niu , Henderson Charles N.R. 
Published: December 2014

Objective
Despite wide use, the value of formative exams remains unclear. We evaluated the possible benefits of formative assessments in a physical examination course at our chiropractic college.

Methods
Three hypotheses were examined: (1) Receiving formative quizzes (FQs) will increase summative exam (SX) scores, (2) writing FQ questions will further increase SE scores, and (3) FQs can predict SX scores. Hypotheses were tested across three separate iterations of the class.

Results
The SX scores for the control group (Class 3) were significantly less than those of Classes 1 and 2, but writing quiz questions and taking FQs (Class 1) did not produce significantly higher SX scores than only taking FQs (Class 2). The FQ scores were significant predictors of SX scores, accounting for 52% of the SX score. Sex, age, academic degrees, and ethnicity were not significant copredictors.

Conclusion
Our results support the assertion that FQs can improve written SX performance, but students producing quiz questions didn't further increase SX scores. We concluded that nonthreatening FQs may be used to enhance student learning and suggest that they also may serve to identify students who, without additional remediation, will perform poorly on subsequent summative written exams.
Plant invasion impacts on the gross and net primary production of the salt marsh on eastern coast of China: Insights from leaf to ecosystem
Authors: Ge Zhen‐Ming , Guo Hai‐Qiang , Zhao Bin , Zhang Li‐Quan 
Published: December 2014

AbstractThe exotic Spartina alterniflora from North America has been rapidly invading the entire Chinese coast, while the impacts of plant invasion on the gross (GPP) and net primary production (NPP) of the coastal salt marshes were less known. In this study, we investigated the photosynthetic performance, leaf characteristics, and primary production of the exotic C4 grass and the dominant native C3 grass (Phragmites australis) in two marsh mixtures (equipped with eddy covariance systems) in the Yangtze Estuary. The light‐saturated photosynthetic rate and annual peak leaf area index (LAI) of S. alterniflora was higher than that of P. australis throughout the growing season. The leaf nitrogen content of P. australis declined sharper during the latter growing season than that of S. alterniflora. The leaf‐to‐canopy production model with species‐specific (C3 and C4 types) parameterizations could reasonably simulate the daily trends and annual GPP amount against the 3 year flux measurements from 2005 to 2007, and the modeled NPP agreed with biomass measurements from the two species during 2012. The percentage contributions of GPP between S. alterniflora and P. australis were on average 5.82:1 and 2.91:1 in the two mixtures, respectively. The annual NPP amounts from S. alterniflora were higher by approximately 1.6 times than that from P. australis. Our results suggested that higher photosynthesis efficiency, higher LAI, and longer growing season resulted in greater GPP and NPP in the exotic species relative to the native species. The rapid expansion rate of S. alterniflora further made it the leading contributor of primary production in the salt marsh.
Tracking gravity waves in moist baroclinic jet‐front systems
Authors: Wei Junhong , Zhang Fuqing 
Published: December 2014

AbstractA series of four‐dimensional ray‐tracing experiments are performed to investigate the propagating wave characteristics, source mechanisms, and wave number vector refraction budget of six groups of lower‐stratospheric gravity waves in the moist baroclinic jet‐front systems with varying degree of convective instability. On one hand, the resemblance of ray trajectories and propagating characteristics between gravity waves in the dry experiment versus those in the experiment with weak diabatic heating demonstrates the limited role of moist convection in modifying those wave modes that are dominated by dry dynamics, including both the short‐scale northward‐propagating mode and the intermediate‐scale northward‐propagating mode in the jet exit region (likely induced by upper‐level jet imbalance and/or tropospheric frontogenesis), the intermediate‐scale eastward‐propagating mode from the jet exit region in the ridge down to the jet entrance region in the trough (likely induced by upper‐level jet imbalance), and the short‐scale southward‐propagating mode located far to the south of the jet right above the surface cold front (likely induced by tropospheric frontogenesis). On the other hand, comparisons of the gravity waves in the two aforementioned experiments through the ray tracing analysis further demonstrate that moist convection may force new wave modes, modify existing dry wave modes through latent heat release, or modify the new/existing waves through modification of large‐scale flow. Convectively generated gravity waves could propagate both upstream and downstream of the latent heating. Lastly, it is indicated in the budget analysis of wave number vector refraction equations that the wind effect on changing the characteristics of propagating gravity waves generally dominates over the thermodynamics effect, and that the thermodynamics effect may counteract, enhance, or even take over the effect of background wind for those wave packets crossing the tropopause or frontal systems.
Time‐domain microfluidic fluorescence lifetime flow cytometry for high‐throughput Förster resonance energy transfer screening
Authors: Nedbal Jakub , Visitkul Viput , Ortiz‐Zapater Elena , Weitsman Gregory , Chana Prabhjoat , Matthews Daniel R. , Ng Tony , Ameer‐Beg Simon M. 
Published: December 2014

AbstractSensing ion or ligand concentrations, physico‐chemical conditions, and molecular dimerization or conformation change is possible by assays involving fluorescent lifetime imaging. The inherent low throughput of imaging impedes rigorous statistical data analysis on large cell numbers. We address this limitation by developing a fluorescence lifetime‐measuring flow cytometer for fast fluorescence lifetime quantification in living or fixed cell populations. The instrument combines a time‐correlated single photon counting epifluorescent microscope with microfluidics cell‐handling system. The associated computer software performs burst integrated fluorescence lifetime analysis to assign fluorescence lifetime, intensity, and burst duration to each passing cell. The maximum safe throughput of the instrument reaches 3,000 particles per minute. Living cells expressing spectroscopic rulers of varying peptide lengths were distinguishable by Förster resonant energy transfer measured by donor fluorescence lifetime. An epidermal growth factor (EGF)‐stimulation assay demonstrated the technique's capacity to selectively quantify EGF receptor phosphorylation in cells, which was impossible by measuring sensitized emission on a standard flow cytometer. Dual‐color fluorescence lifetime detection and cell‐specific chemical environment sensing were exemplified using di‐4‐ANEPPDHQ, a lipophilic environmentally sensitive dye that exhibits changes in its fluorescence lifetime as a function of membrane lipid order. To our knowledge, this instrument opens new applications in flow cytometry which were unavailable due to technological limitations of previously reported fluorescent lifetime flow cytometers. The presented technique is sensitive to lifetimes of most popular fluorophores in the 0.5–5 ns range including fluorescent proteins and is capable of detecting multi‐exponential fluorescence lifetime decays. This instrument vastly enhances the throughput of experiments involving fluorescence lifetime measurements, thereby providing statistically significant quantitative data for analysis of large cell populations. © 2014 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of ISAC.
Sophorolipids: Expanding structural diversity by ring‐opening cross‐metathesis
Authors: Peng Yifeng , Totsingan Filbert , Meier Michael A. R. , Steinmann Mark , Wurm Frederik , Koh Amanda , Gross Richard A. 
Published: December 2014

Lactonic sophorolipids (LSL) are glycolipid biosurfactants produced in large quantity by yeast fermentation. Chemical or enzymatic modification of naturally produced sophorolipids is an effective route to improve their functional properties. For the first time, ring‐opening cross metathesis (RO/CM) was used to convert natural LSL to a unique family of modified sophorolipids. Reaction conditions for RO/CM of LSL with n‐alkyl acrylates, trans‐3‐hexene, 1‐hexene and ethylene were investigated. For the RO/CM of n‐alkyl acrylates with LSL, %‐conversions greater than 95% within 1 h resulted from conducting reactions in THF at 60°C using 5 mol% of Grubbs second generation ruthenium based catalyst (M2). The RO/CM reaction of LSL with ethylene performed at 3 bar under an ethylene atmosphere using Grubbs first generation (G1) (10 mol%) as the catalyst in dichloromethane (room temperature, 5 h) gave complete conversion of LSL to the corresponding ring‐opened product. Ethanolysis of LSL RO/CM products generated a series of medium chain (C10‐C14) SL‐surfactants and fatty acid co‐products. Values of surface tension reduction at the air‐water interface versus Log (C) for modified SLs were measured by the Wilhelmy plate method. Minimum surface tension values varied as a function of the hydrophobic character of modified SLs. The modified SL from RO/CM with 1‐hexene (SL‐14) gave the largest surface tension reduction and lowest CMC (to 34 mN/m and 0.15 mM, respectively) and showed a similar surface tension reduction behavior as n‐dodecyl‐β‐D‐maltoside (Mal‐C12). Increasing the number of carbons in the hydrophobic segment for the homologous series of n‐alkyl sophorosides results in an almost linear decrease in log(CMC), with B = 0.18 ± 0.03. This number is smaller than that of other related surfactants such as alkyl‐β‐D‐glycosides and alkyl‐β‐D‐maltosides.Practical applications: Modified sophorolipids can be used in a wide variety of applications such as stabilization of oil‐in‐water dispersions, antimicrobials and various cleaning operations.Ring‐opening cross‐metathesis was used to expand structural diversity of natural sophorolipid surfactants.
Assessment of interactive effects of elevated salinity and three pesticides on life history and behavior of southern toad (Anaxyrus terrestris) tadpoles
Authors: Wood Liza , Welch Allison M. 
Published: December 2014

Abstract

Because habitats are increasingly exposed to multiple stressors simultaneously, assessing the interactive effects of stressors is crucial for understanding how populations respond to human-altered habitats. Salinization of freshwater habitats is increasing and has the potential to interact with other stressors. Chemical pollutants also contribute to habitat degradation in freshwater environments, and both salinity and various pesticides can harm amphibians. The present study used a factorial experiment to investigate the effect of elevated salinity alone and in combination with each of 3 pesticides—atrazine, carbaryl, and glyphosate—on life history and behavior of southern toad larvae (Anaxyrus terrestris). Tadpoles were negatively affected by elevated salinity and by exposure to the insecticide carbaryl, with the most deleterious outcomes associated with both stressors combined. Carbaryl exposure led to reduced survival as well as sublethal effects on growth, activity and feeding behavior, escape response swimming, and time to metamorphosis. Tadpoles reared at elevated salinity were also smaller and less active, and ultimately metamorphosed later and at smaller size. Together, carbaryl and elevated salinity had a synergistic effect, resulting in particularly poor growth, depressed activity and feeding, and sluggish escape swimming among tadpoles exposed to both stressors simultaneously. These results suggest that both elevated salinity and carbaryl represent threats for amphibian populations and that pesticide exposure in salinized habitats may pose a particularly high risk. Environ Toxicol Chem 2015;34:667–676. © 2014 SETAC
p53 Loss Increases the Osteogenic Differentiation of Bone Marrow Stromal Cells
Authors: He Yunlong , de Castro Luis F. , Shin Min Hwa , Dubois Wendy , Yang Howard H. , Jiang Shunlin , Mishra Pravin J. , Ren Ling , Gou Hongfeng , Lal Ashish , Khanna Chand , Merlino Glenn , Lee Maxwell , Robey Pamela G. , Huang Jing 
Published: December 2014

AbstractThe tumor suppressor, p53, plays a critical role in suppressing osteosarcoma. Bone marrow stromal cells (BMSCs, also known as bone marrow-derived mesenchymal stem cells) have been suggested to give rise to osteosarcomas. However, the role of p53 in BMSCs has not been extensively explored. Here, we report that p53 regulates the lineage choice of mouse BMSCs (mBMSCs). Compared to mBMSCs with wild-type p53, mBMSCs deficient in p53 have enhanced osteogenic differentiation, but with similar adipogenic and chondrogenic differentiation. The role of p53 in inhibiting osteogenic lineage differentiation is mainly through the action of Runx2, a master transcription factor required for the osteogenic differentiation of mBMSCs. We find that p53 indirectly represses the expression of Runx2 by activating the microRNA-34 family, which suppresses the translation of Runx2. Since osteosarcoma may derive from BMSCs, we examined whether p53 has a role in the osteogenic differentiation of osteosarcoma cells and found that osteosarcoma cells with p53 deletion have higher levels of Runx2 and faster osteogenic differentiation than those with wild-type p53. A systems biology approach reveals that p53-deficient mBMSCs are more closely related to human osteosarcoma while mBMSCs with wild-type p53 are similar to normal human BMSCs. In summary, our results indicate that p53 activity can influence cell fate specification of mBMSCs, and provide molecular and cellular insights into the observation that p53 loss is associated with increased osteosarcoma incidence. Stem Cells 2015;33:1304–1319
A Structured Approach for Rapidly Mapping Multilevel System Measures via Simulation Metamodeling
Authors: Rosen Scott L. , Saunders Christopher P. , Guharay Samar K 
Published: December 2014

ABSTRACTWith increasing complexity of real‐world systems, especially for continuously evolving scenarios, systems analysts encounter a major challenge with the modeling techniques that capture detailed system characteristics defining input–output relationships. The models become very complex and require long time of execution. In this situation, techniques to construct approximations of the simulation model by metamodeling alleviate long run times and the need for large computational resources; it also provides a means to aggregate a simulation's multiple outputs of interest and derives a single decision‐making metric. The method described here leverages simulation metamodeling to map the three basic SE metrics, namely, measures of performance to measures of effectiveness to a single figure of merit. This enables using metamodels to map multilevel system measures supports rapid decision making. The results from a case study demonstrate the merit of the method. Several metamodeling techniques are compared and bootstrap error analysis and predicted residual sums of squares statistic are discussed to evaluate the standard error and error due to bias.
Computational analysis of the flow field structure of a non-reacting hypersonic flow over forward-facing steps
Authors: Leite P. H. M. , Santos W. F. N. 
Published: December 2014

AbstractThis work is a computational study of a rarefied non-reacting hypersonic flow past a forward-facing step at zero-degree angle of attack in thermal non-equilibrium. Effects on the flow field structure and on the aerodynamic surface quantities due to changes in step frontal-face height are investigated by employing the direct simulation Monte Carlo method. The work focuses the attention of designers of hypersonic configurations on the fundamental parameter of surface discontinuity, which can have an important impact on even initial design. The results presented highlight the sensitivity of the primary flow field properties, velocity, density, pressure and temperature, to changes in the step frontal-face height. In addition, the behaviour of heat transfer, pressure and skin friction coefficients with variation of the step frontal-face height is detailed. The analysis shows that hypersonic flow past a forward-facing step in the transition flow regime is characterized by a strong compression ahead of the frontal face, which influences the aerodynamic surface properties upstream and adjacent to the frontal face. The analysis also shows that the extension of the upstream disturbance depends on the step frontal-face height. It was found that the recirculation region ahead of the step is also a function of the frontal-face height. A sequence of Moffatt eddies of decreasing size and intensity is observed in the concave step corner. Locally high heating and pressure loads were observed at three locations along the surface, i.e. on the lower surface, on the frontal face and on the upper surface. The results showed that both loads rely on the frontal-face height. The peak values for the heat transfer coefficient on the frontal-face surface were at least one order of magnitude larger than the maximum value observed for a smooth surface, i.e. a flat plate without a step. A comparison of the present simulation results with numerical and experimental data showed close agreement concerning the wall pressure acting on the step surface.
ADHM CONSTRUCTION OF PERVERSE INSTANTON SHEAVES
Authors: HENNI ABDELMOUBINE AMAR , JARDIM MARCOS , MARTINS RENATO VIDAL 
Published: December 2014

AbstractWe present a construction of framed torsion free instanton sheaves on a projective variety containing a fixed line which further generalises the one on projective spaces. This is done by generalising the so called ADHM variety. We show that the moduli space of such objects is a quasi projective variety, which is fine in the case of projective spaces. We also give an ADHM categorical description of perverse instanton sheaves in the general case, along with a hypercohomological characterisation of these sheaves in the particular case of projective spaces.
SINGULAR COTANGENT MODEL
Authors: CURRÁS-BOSCH CARLOS 
Published: December 2014

AbstractAny singular level of a completely integrable system (c.i.s.) with non-degenerate singularities has a singular affine structure. We shall show how to construct a simple c.i.s. around the level, having the above affine structure. The cotangent bundle of the desingularized level is used to perform the construction, and the c.i.s. obtained looks like the simplest one associated to the affine structure. This method of construction is used to provide several examples of c.i.s. with different kinds of non-degenerate singularities.
FINITISTIC DIMENSIONS AND PIECEWISE HEREDITARY PROPERTY OF SKEW GROUP ALGEBRAS
Authors: LI LIPING 
Published: December 2014

AbstractLet Λ be a finite-dimensional algebra andGbe a finite group whose elements act on Λ as algebra automorphisms. Assume that Λ has a complete setEof primitive orthogonal idempotents, closed under the action of a Sylowp-subgroupS≤G. If the action ofSonEis free, we show that the skew group algebra ΛGand Λ have the same finitistic dimension, and have the same strong global dimension if the fixed algebra ΛSis a direct summand of the ΛS-bimodule Λ. Using a homological characterization of piecewise hereditary algebras proved by Happel and Zacharia, we deduce a criterion for ΛGto be piecewise hereditary.
ON BI-HARMONIC HYPERSURFACES IN EUCLIDEAN SPACE OF ARBITRARY DIMENSION
Authors: GUPTA RAM SHANKAR 
Published: December 2014

AbstractThe following Chen's bi-harmonic conjecture made in 1991 is well-known and stays open: The only bi-harmonic submanifolds of Euclidean spaces are the minimal ones. In this paper, we prove that the bi-harmonic conjecture is true for bi-harmonic hypersurfaces with three distinct principal curvatures of a Euclidean space of arbitrary dimension.
GROWTH CONDITIONS FOR OPERATORS WITH SMALLEST SPECTRUM
Authors: MUSTAFAYEV H. S. 
Published: December 2014

AbstractLet A be an invertible operator on a complex Banach space X. For a given α ≥ 0, we define the class $\mathcal{D}$Aα(ℤ) (resp. $\mathcal{D}$Aα (ℤ+)) of all bounded linear operators T on X for which there exists a constant CT>0, such that
$
\begin{equation*}
\Vert A^{n}TA^{-n}\Vert \leq C_{T}\left( 1+\left\vert
n\right\vert \right) ^{\alpha },
\end{equation*}
$
for all n ∈ ℤ (resp. n∈ ℤ+). We present a complete description of the class $\mathcal{D}$Aα (ℤ) in the case when the spectrum of A is real or is a singleton. If T ∈ $\mathcal{D}$A(ℤ) (=$\mathcal{D}$A0(ℤ)), some estimates for the norm of AT-TA are obtained. Some results for the class $\mathcal{D}$Aα (ℤ+) are also given.
Childhood somatic complaints predict generalized anxiety and depressive disorders during young adulthood in a community sample
Authors: Shanahan L. , Zucker N. , Copeland W. E. , Bondy C. L. , Egger H. L. , Costello E. J. 
Published: December 2014

BackgroundChildren with somatic complaints are at increased risk for emotional disorders during childhood. Whether this elevated risk extends into young adulthood – and to which specific disorders – has rarely been tested with long-term prospective-longitudinal community samples. Here we test whether frequent and recurring stomach aches, headaches, and muscle aches during childhood predict emotional disorders in adulthood after accounting for childhood psychiatric and physical health status and psychosocial adversity.MethodThe Great Smoky Mountains Study is a community representative sample with 1420 participants. Children/adolescents were assessed 4–7 times between ages 9–16 years. They were assessed again up to three times between ages 19–26 years. Childhood somatic complaints were coded when subjects or their parents reported frequent and recurrent headaches, stomach aches, or muscular/joint aches at some point when children were aged 9–16 years. Psychiatric disorders were assessed with the Child and Adolescent Psychiatric Assessment and the Young Adult Psychiatric Assessment.ResultsFrequent and recurrent somatic complaints in childhood predicted adulthood emotional disorders. After controlling for potential confounders, predictions from childhood somatic complaints were specific to later depression and generalized anxiety disorder. Long-term predictions did not differ by sex. Somatic complaints that persisted across developmental periods were associated with the highest risk for young adult emotional distress disorders.ConclusionsChildren from the community with frequent and recurrent physical distress are at substantially increased risk for emotional distress disorders during young adulthood. Preventions and interventions for somatic complaints could help alleviate this risk.