bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Investigation of the Learning Strategies as Bias Factors in Second Language Cloze Tests
Authors: Ajideh Parviz , Yaghoubi-Notash Massoud , Khalili Abdolreza 
Published: April 2017

The present study investigated the contribution of the EFL students’ learning strategies to the explanation of the variance in their results on language tests. More specifically, it examined the role of these strategies as bias factors in the results of English cloze tests. Based on this aim, first, 158 intermediate EFL learners were selected from among 324 language learners of a private language institute in Urmia (Iran) as the participants of the study based on their results on a proficiency test. Second, the selected participants respectively received Oxford’s (1990) Strategy Inventory for Language Learning (SILL) and the cloze test of the study for the assessment of their learning strategies and English cloze test performance during two sessions in a one-week period. The standard multiple regression was employed for data analysis. The results of the study showed that, there were significant positive correlations between the learners’ metacognitive strategies and cognitive strategies and their cloze test performance. Based on these results, it was argued that, the learners’ learning strategies may be systematic test bias factors in second language cloze tests. The results of the present study may have useful practical implications for the EFL teachers and syllabus designers. Moreover, these results may provide certain theoretical guidelines for second language testing specialists.
The observed cooling effect of desert blooms based on high‐resolution Moderate Resolution Imaging Spectroradiometer products
Authors: He Bin , Huang Ling , Liu Junjie , Wang Haiyan , Lű Aifeng , Jiang Weiguo , Chen Ziyue 
Published: April 2017

AbstractDesert greening through planting or irrigation is a potential approach to mitigate desertification and climate warming, but its influence on regional climate is unclear due to scarcity of observations. “Desert blooms,” which are natural phenomena usually associated with the El Niño–Southern Oscillation, regularly occur in the world's driest desert, the Atacama Desert. This sudden conversion of land cover likely has a large impact on regional climate through alteration of local energy budgets and provides a unique opportunity to study the potential climatic and environmental consequences of desert greening. Here we evaluated the land surface effects of blooms in the Atacama Desert using vegetation and climate data acquired from remote sensing. The rapid vegetation growth during blooms led to an increase in evapotranspiration and a decrease in albedo. These two processes caused a 0.31°C ± 0.05°C decrease in daytime land surface temperature. During nighttime, we observed a 0.02°C ± 0.02°C increase in land surface temperature due to enhanced heat capacity associated with blooms. This asymmetric diurnal variation in land surface temperature produced a net decrease in daily land surface temperature of 0.29°C ± 0.07°C. Our observations demonstrate the potential benefits of desert blooms on local climate. Results from this study also provide new evidence for plausible climate consequences expected from local “desert greening” strategies.
Delineating environmental control of phytoplankton biomass and phenology in the Southern Ocean
Authors: Ardyna Mathieu , Claustre Hervé , Sallée Jean‐Baptiste , D'Ovidio Francesco , Gentili Bernard , van Dijken Gert , D'Ortenzio Fabrizio , Arrigo Kevin R. 
Published: April 2017

AbstractThe Southern Ocean (SO), an area highly sensitive to climate change, is currently experiencing rapid warming and freshening. Such drastic physical changes might significantly alter the SO's biological pump. For more accurate predictions of the possible evolution of this pump, a better understanding of the environmental factors controlling SO phytoplankton dynamics is needed. Here we present a satellite‐based study deciphering the complex environmental control of phytoplankton biomass (PB) and phenology (PH; timing and magnitude of phytoplankton blooms) in the SO. We reveal that PH and PB are mostly organized in the SO at two scales: a large latitudinal scale and a regional scale. Latitudinally, a clear gradient in the timing of bloom occurrence appears tightly linked to the seasonal cycle in irradiance, with some exceptions in specific light‐limited regimes (i.e., well‐mixed areas). Superimposed on this latitudinal scale, zonal asymmetries, up to 3 orders of magnitude, in regional‐scale PB are mainly driven by local advective and iron supply processes. These findings provide a global understanding of PB and PH in the SO, which is of fundamental interest for identifying and explaining ongoing changes as well as predicting future changes in the SO biological pump.
Energy‐optimal path planning in the coastal ocean
Authors: Subramani Deepak N. , Haley Patrick J. , Lermusiaux Pierre F. J. 
Published: April 2017

AbstractWe integrate data‐driven ocean modeling with the stochastic Dynamically Orthogonal (DO) level‐set optimization methodology to compute and study energy‐optimal paths, speeds, and headings for ocean vehicles in the Middle‐Atlantic Bight (MAB) region. We hindcast the energy‐optimal paths from among exact time‐optimal paths for the period 28 August 2006 to 9 September 2006. To do so, we first obtain a data‐assimilative multiscale reanalysis, combining ocean observations with implicit two‐way nested multiresolution primitive‐equation simulations of the tidal‐to‐mesoscale dynamics in the region. Second, we solve the reduced‐order stochastic DO level‐set partial differential equations (PDEs) to compute the joint probability of minimum arrival time, vehicle‐speed time series, and total energy utilized. Third, for each arrival time, we select the vehicle‐speed time series that minimize the total energy utilization from the marginal probability of vehicle‐speed and total energy. The corresponding energy‐optimal path and headings are obtained through the exact particle‐backtracking equation. Theoretically, the present methodology is PDE‐based and provides fundamental energy‐optimal predictions without heuristics. Computationally, it is 3–4 orders of magnitude faster than direct Monte Carlo methods. For the missions considered, we analyze the effects of the regional tidal currents, strong wind events, coastal jets, shelfbreak front, and other local circulations on the energy‐optimal paths. Results showcase the opportunities for vehicles that intelligently utilize the ocean environment to minimize energy usage, rigorously integrating ocean forecasting with optimal control of autonomous vehicles.
Concise Synthesis of Spiro[indoline‐3,2′‐pyrrolidine] and 1‐Azacarbazole Derivatives via Copper‐Catalyzed Cyclization of Indoles
Authors: Wang Peng‐Fei , Chen Chao , Chen Hui , Han Li‐Shuai , Liu Liu , Sun Hongbin , Wen Xiaoan , Xu Qing‐Long 
Published: April 2017

AbstractA high‐yielding, copper‐catalyzed dearomatization reaction of indole from 2‐methylindole‐derived oxime acetates was realized, providing access to structurally novel spiro[indoline‐3,2′‐pyrrolidine] derivatives in 67–98% yields. When the C‐2 position of the indole was not substituted, azacarbazole derivatives were obtained in moderate yields. This transformation provides an efficient approach to access nitrogen‐containing spiroindolenine and azacarbazole derivatives with wide substrate scope.magnified image
Synthesis and Cytotoxic Evaluation of N‐Aroylureas through Rhodium(III)‐Catalyzed C−H Functionalization of Indolines with Isocyanates
Authors: Jeong Taejoo , Lee Suk Hun , Mishra Neeraj Kumar , De Umasankar , Park Jihye , Dey Prasanta , Kwak Jong Hwan , Jung Young Hoon , Kim Hyung Sik , Kim In Su 
Published: April 2017

AbstractThe rhodium(III)‐catalyzed C−H amidation and subsequent C−N bond formation reaction of indolines with aryl and alkyl isocyanates at room temperature are reported. These transformations allow the generation of N‐aroylurea functionality at the C7‐position of indolines, which is known as a crucial scaffold found in biologically active molecules. In addition, the synthesis of pyrroloindolidione derivatives is also described through sequential C6‐amidation reaction and intramolecular cyclization of C7‐amidated indolines. All synthesized products were evaluated for in vitro cytotoxic effect against human prostate adenocarcinoma cells (DU145), human breast cancer cells (MCF‐7), and triple negative human breast cancer cells (MDA‐MB‐231), respectively. Notably, compounds 4 d and 4 e with linear alkyl side chains were found to be highly cytotoxic, which is comparable to that of anticancer doxorubicin and cisplatin as positive controls.magnified image
Conditional random slope: A new approach for estimating individual child growth velocity in epidemiological research
Authors: Leung Michael , Bassani Diego G. , Racine‐Poon Amy , Goldenberg Anna , Ali Syed Asad , Kang Gagandeep , Premkumar Prasanna S. , Roth Daniel E. 
Published: April 2017

AbstractObjectivesConditioning child growth measures on baseline accounts for regression to the mean (RTM). Here, we present the “conditional random slope” (CRS) model, based on a linear‐mixed effects model that incorporates a baseline‐time interaction term that can accommodate multiple data points for a child while also directly accounting for RTM.METHODSIn two birth cohorts, we applied five approaches to estimate child growth velocities from 0 to 12 months to assess the effect of increasing data density (number of measures per child) on the magnitude of RTM of unconditional estimates, and the correlation and concordance between the CRS and four alternative metrics. Further, we demonstrated the differential effect of the choice of velocity metric on the magnitude of the association between infant growth and stunting at 2 years.RESULTSRTM was minimally attenuated by increasing data density for unconditional growth modeling approaches. CRS and classical conditional models gave nearly identical estimates with two measures per child. Compared to the CRS estimates, unconditional metrics had moderate correlation (r = 0.65–0.91), but poor agreement in the classification of infants with relatively slow growth (kappa = 0.38–0.78). Estimates of the velocity‐stunting association were the same for CRS and classical conditional models but differed substantially between conditional versus unconditional metrics.CONCLUSIONThe CRS can leverage the flexibility of linear mixed models while addressing RTM in longitudinal analyses.
Stuck in fragments: Population genetics of the Endangered collared brown lemurEulemur collarisin the Malagasy littoral forest
Authors: Bertoncini Stefania , D'Ercole Jacopo , Brisighelli Francesca , Ramanamanjato Jean‐Baptiste , Capelli Cristian , Tofanelli Sergio , Donati Giuseppe 
Published: April 2017

AbstractObjectivesThe Endangered collared brown lemur (Eulemur collaris) is the largest primate living in the littoral forest of southeastern Madagascar, a top priority habitat for biodiversity conservation on the island. Because this lemur is a key seed‐disperser, an evaluation of the structure and connectivity of the populations surviving in the forest fragments is urgently needed to guide conservation plans.Materials and MethodsGenetic variability at autosomal microsatellites and mitochondrial DNA was investigated in a total of 49 collared brown lemurs sampled by non‐invasive methods in three littoral forest fragments and in the nearby lowland humid forest.ResultsThe overall genetic diversity ofE. collarisin the southeastern coastal region of Madagascar was lower than in other populations, as well as in other lemur species. The population appears highly structured, with less variable and more inbred groups inhabiting the littoral forest fragments compared to the inland area. Major barriers to gene flow were identified isolating littoral forest fragments from each other and from the inland lowland humid forest.DiscussionMedium to long‐term drift and scarce gene flow is the scenario that best explains the current genetic distribution. Habitat discontinuities such as rivers and grassland between forest fragments played a major role in structuring the population. A common history of size contraction is pointed out by several genetic estimators, indicating a possible ecological crisis triggered around 1,300 years ago. The adoption of strategies aimed at facilitating gene flow and population growth appears crucial to delay further loss of genetic diversity.
Enantioselective Silver and Amine Co‐catalyzed Desymmetrizing Cycloisomerization of Alkyne‐Linked Cyclohexanones
Authors: Manzano Rubén , Datta Swarup , Paton Robert S. , Dixon Darren J. 
Published: April 2017

AbstractA silver(I) and amine co‐catalyzed desymmetrization of 4‐propargylamino cyclohexanones for the direct enantioselective synthesis of 2‐azabicyclo[3.3.1]nonanes is described. Exploiting reactivity arising from dual activation of the pendant terminal alkyne by silver(I) and the ketone moiety through transient enamine formation, this synthetically relevant transformation is easy to perform, efficient and broad in scope. High enantioselectivity (up to 96 % ee) was achieved by exploiting a significant matching effect between the chirality of a cinchona alkaloid‐derived aminophosphine ligand for the silver(I) salt and the 2‐bis(aryl)methylpyrrolidine catalyst which was rationalized by DFT calculations. This allowed for the preparation of both enantiomers of the bicyclic product with near‐identical stereocontrol.
Cleavage of a P=P Double Bond Mediated by N‐Heterocyclic Carbenes
Authors: Hayakawa Naoki , Sadamori Kazuya , Tsujimoto Shota , Hatanaka Miho , Wakabayashi Tomonari , Matsuo Tsukasa 
Published: April 2017

AbstractThe reaction of the bulky diphosphenes (Rind)P=P(Rind) (1; Rind=1,1,3,3,5,5,7,7‐octa‐R‐substituted s‐hydrindacen‐4‐yl) with two molecules of N‐heterocyclic carbene (NHC; 1,3,4,5‐tetramethylimidazol‐2‐ylidene) resulted in the quantitative formation of the NHC‐bound phosphinidenes NHC→P(Rind) (2), along with the cleavage of the P=P double bond. The reaction times are dependent on the steric size of the Rind groups (11 days for 2 a (R=Et) and 2 h for 2 b (R=Et, Me) at room temperature). The mechanism for the double bond‐breaking is proposed to proceed via the formation of the NHC‐coordinated, highly polarized diphospehenes 3 as an intermediate. Approach of a second NHC to 3 induces P−P bond cleavage and P−C bond formation, which proceeds through a transition state with a large negative Gibbs energy change to afford the two molecules of 2, thus being the rate‐determining step of the overall reaction with the activation barriers of 80.4 for 2 a and 29.1 kJ mol−1 for 2 b.
Layered Double Hydroxide Nanosheets with Multiple Vacancies Obtained by Dry Exfoliation as Highly Efficient Oxygen Evolution Electrocatalysts
Authors: Wang Yanyong , Zhang Yiqiong , Liu Zhijuan , Xie Chao , Feng Shi , Liu Dongdong , Shao Mingfei , Wang Shuangyin 
Published: April 2017

AbstractLayered double hydroxides (LDHs) with two‐dimensional lamellar structures show excellent electrocatalytic properties. However, the catalytic activity of LDHs needs to be further improved as the large lateral size and thickness of the bulk material limit the number of exposed active sites. However, the development of efficient strategies to exfoliate bulk LDHs into stable monolayer LDH nanosheets with more exposed active sites is very challenging. On the other hand, the intrinsic activity of monolayer LDH nanosheets can be tuned by surface engineering. Herein, we have exfoliated bulk CoFe LDHs into ultrathin LDH nanosheets through Ar plasma etching, which also resulted in the formation of multiple vacancies (including O, Co, and Fe vacancies) in the ultrathin 2D nanosheets. Owing to their ultrathin 2D structure, the LDH nanosheets expose a greater number of active sites, and the multiple vacancies significantly improve the intrinsic activity in the oxygen evolution reaction (OER).
The Dynamics of the Reaction of FeO+ and H2: A Model for Inorganic Oxidation
Authors: Essafi Stéphanie , Tew David P. , Harvey Jeremy N. 
Published: April 2017

AbstractExtensive density functional theory (DFT) calculations using the B3LYP functional were used to explore the sextet and quartet energy potential energy surfaces (PESs) of the title reaction, and as a basis to fit global analytical reactive PESs. Surface‐hopping dynamics on these PESs reproduce the experimentally observed reactivity and confirm that hydrogen activation rather than spin‐state change is rate‐limiting at low reaction energy, where the main products are Fe+ and H2O. A change in spin state is inefficient in the product region so that excited‐state 4Fe+ is the dominant product. At higher energies, spin‐allowed hydrogen atom abstraction to form FeOH+ predominates. At intermediate energy, a previously unexpected rebound mechanism contributes significantly to the reactivity.
Base‐Controlled Completely Selective Linear or Branched Rhodium(I)‐Catalyzed C−H ortho‐Alkylation of Azines without Preactivation
Authors: Tran Gaël , Hesp Kevin D. , Mascitti Vincent , Ellman Jonathan A. 
Published: April 2017

AbstractA [RhI]/bisphosphine/base catalytic system for the ortho‐selective C−H alkylation of azines by acrylates and acrylamides is reported. This catalytic system features an unprecedented complete linear or branched selectivity that is solely dependent on the catalytic base that is used. Complete branched selectivity is even achieved for ethyl methacrylate, which enables the introduction of a quaternary carbon center. Excellent functional group compatibility is demonstrated for both linear and branched alkylations. The operational simplicity and broad scope of this transformation allow for rapid access to functionalized azines of direct pharmaceutical and agrochemical relevance.
Global Mapping of Protein–Lipid Interactions by Using Modified Choline‐Containing Phospholipids Metabolically Synthesized in Live Cells
Authors: Wang Danyang , Du Shubo , Cazenave‐Gassiot Amaury , Ge Jingyan , Lee Jun‐Seok , Wenk Markus R. , Yao Shao Q. 
Published: April 2017

AbstractThe protein–lipid interaction is an essential metabolic process that mediates cellular signaling and functions. Existing strategies for large‐scale mapping studies of the protein–lipid interaction fall short in their incompatibility with metabolic incorporation or inability to remove unwanted interferences from lipidated proteins. By incorporating an alkyne‐containing choline head group and a diazirine‐modified fatty acid simultaneously into choline‐containing phospholipids synthesized from live mammalian cells, protein–phospholipid interactions have been successfully imaged in live cells. Subsequent in situ profiling of the modified Cho phospholipid‐crosslinked proteins followed by quantitative proteomics allowed identification of several hundred putative phospholipid‐interacting proteins, some of which were further validated.
N‐Heterocyclic Carbene Catalyzed [4+2] Annulation of Enals via a Double Vinylogous Michael Addition: Asymmetric Synthesis of 3,5‐Diaryl Cyclohexenones
Authors: Chen Xiang‐Yu , Liu Qiang , Chauhan Pankaj , Li Sun , Peuronen Anssi , Rissanen Kari , Jafari Ehsan , Enders Dieter 
Published: April 2017

AbstractA strategy for the N‐heterocyclic carbene (NHC) catalyzed asymmetric synthesis of 3,5‐diaryl substituted cyclohexenones has been developed via oxidative [4+2] annulation of enals and alkenylisoxazoles. It is the first example of using NHC organocatalysis in a double vinylogous Michael type reaction, a challenging but highly desirable topic. This unprecedented protocol affords good yields as well as high to excellent diastereo‐ and enantioselectivities.
Poly‐cytosine DNA as a High‐Affinity Ligand for Inorganic Nanomaterials
Authors: Lu Chang , Huang Zhicheng , Liu Biwu , Liu Yibo , Ying Yibin , Liu Juewen 
Published: April 2017

AbstractAttaching DNA to nanomaterials is the basis for DNA‐directed assembly, sensing, and drug delivery using such hybrid materials. Poly‐cytosine (poly‐C) DNA is a high affinity ligand for four types of commonly used nanomaterials, including nanocarbons (graphene oxide and single‐walled carbon nanotubes), transition metal dichalcogenides (MoS2 and WS2), metal oxides (Fe3O4 and ZnO), and metal nanoparticles (Au and Ag). Compared to other homo‐DNA sequences, poly‐C DNA has the highest affinity for the first three types of materials. Using a diblock DNA containing a poly‐C block to attach to surfaces, the target DNA was successfully hybridized to the other block on graphene oxide more efficiently than that containing a typical poly‐A block, especially in the presence of non‐specific background DNA, proteins, or surfactants. This work provides a simple solution for functionalizing nanomaterials with non‐modified DNA and offers new insights into DNA biointerfaces.
Microporous Polyamide Membranes for Molecular Sieving of Nitrogen from Volatile Organic Compounds
Authors: Zhou Haoli , Tao Fei , Liu Quan , Zong Chunxin , Yang Wenchao , Cao Xingzhong , Jin Wanqin , Xu Nanping 
Published: April 2017

AbstractMicroporous polymer membranes continue to receive tremendous attention for energy‐efficient gas separation processes owing to their high separation performances. A new network microporous polyamide membrane with good molecular‐sieving performance for the separation of N2 from a volatile organic compound (VOC) mixture is described. Triple‐substituted triptycene was used as the main monomer to form a fisherman's net‐shaped polymer, which readily forms a composite membrane by solution casting. This membrane exhibited outstanding separation performance and good stability for the molecular‐sieving separation of N2 over VOCs such as cyclohexane. The rejection rate of the membrane reached 99.2 % with 2098 Barrer N2 permeability at 24 °C under 4 kPa. This approach promotes development of microporous membranes for separation of condensable gases.
Non‐Pincer‐Type Manganese Complexes as Efficient Catalysts for the Hydrogenation of Esters
Authors: van Putten Robbert , Uslamin Evgeny A. , Garbe Marcel , Liu Chong , Gonzalez‐de‐Castro Angela , Lutz Martin , Junge Kathrin , Hensen Emiel J. M. , Beller Matthias , Lefort Laurent , Pidko Evgeny A. 
Published: April 2017

AbstractCatalytic hydrogenation of carboxylic acid esters is essential for the green production of pharmaceuticals, fragrances, and fine chemicals. Herein, we report the efficient hydrogenation of esters with manganese catalysts based on simple bidentate aminophosphine ligands. Monoligated Mn PN complexes are particularly active for the conversion of esters into the corresponding alcohols at Mn concentrations as low as 0.2 mol % in the presence of sub‐stoichiometric amounts of KOtBu base.
Metal‐Free Formal Oxidative C−C Coupling by In Situ Generation of an Enolonium Species
Authors: Kaiser Daniel , de la Torre Aurélien , Shaaban Saad , Maulide Nuno 
Published: April 2017

AbstractMuch contemporary organic synthesis relies on transformations that are driven by the intrinsic, so‐called “natural”, polarity of chemical bonds and reactive centers. The design of unconventionally polarized synthons is a highly desirable strategy, as it generally enables unprecedented retrosynthetic disconnections for the synthesis of complex substances. Whereas the umpolung of carbonyl centers is a well‐known strategy, polarity reversal at the α‐position of a carbonyl group is much rarer. Herein, we report the design of a novel electrophilic enolonium species and its application in efficient and chemoselective, metal‐free oxidative C−C coupling.