bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring Collective Mathematical Creativity in Elementary School
Authors: LEVENSON ESTHER 
Published: December 2011

AbstractThis study combines theories related to collective learning and theories related to mathematical creativity to investigate the notion of collective mathematical creativity in elementary school classrooms. Collective learning takes place when mathematical ideas and actions, initially stemming from an individual, are built upon and reworked, producing a solution which is the product of the collective. Referring to characteristics of individual mathematical creativity, such as fluency, flexibility, and originality, this paper examines the possibility that collective mathematical creativity may be similarly characterized. The paper also explores the role of the teacher in fostering collective mathematical creativity and the possible relationship between individual and collective mathematical creativity.Many studies have investigated ways of characterizing, identifying, and promoting mathematical creativity. Haylock (1997), for example, and more recently, Kwon, Park, and Park (2006) assessed students' mathematical creativity by employing open‐ended problems and measuring divergent thinking skills. Leikin (2009) explored the use of multiple solution tasks in evaluating a student's mathematical creativity. These studies focused on an individual's mathematical creativity as it manifests itself in the solving of various problems. Yet students, acting in a classroom community, do not necessarily act on their own. Ideas are interchanged, evaluated, and built‐upon, often with the guidance of the teacher. The resultant mathematical creativity of an individual may be a product of collective community practice. The question which then arises is: Who is being mathematically creative, the individual or the community? This study focuses on the collective, not as the aggregation of a few individuals, but as a unit of study. Although some of the studies mentioned above acknowledged the effect of classroom culture on the development of mathematical creativity, and others considered the creative range of a group of students, those studies did not necessarily investigate mathematical creativity as a collective process or as the product of participating in a collective endeavour.This study combines theories related to collective learning and theories related to mathematical creativity to investigate the notion of collective mathematical creativity. The notion of collective creativity has been used to investigate creativity in several contexts including the work place (Hargadon & Bechky, 2006) and the global community (Family, 2003). In those cases, collective creativity was considered to occur when the social interactions between individuals yielded new interpretations that the individuals involved, thinking alone, could not have generated. Can the notion of collective creativity also be applied to the classroom community?
miRNA expression profile during osteogenic differentiation of human adipose‐derived stem cells
Authors: Zhang Zi‐ji , Zhang Hao , Kang Yan , Sheng Pu‐yi , Ma Yuan‐chen , Yang Zi‐bo , Zhang Zhi‐qi , Fu Ming , He Ai‐shan , Liao Wei‐ming 
Published: December 2011

AbstractHuman adipose‐derived stem cells (hADSC) are capable of differentiating into an osteogenic lineage. It is believed that microRNAs (miRNAs) play important roles in regulating this osteogenic differentiation of human adipose‐derived cells, although its molecular mechanism remains unclear. We investigated the miRNA expression profile during osteogenic differentiation of hADSCs, and assessed the roles of involved miRNAs during the osteogenic differentiation. We obtained and cultured human adipose‐derived stems cells from donors who underwent elective liposuction or other abdominal surgery at our institution. miRNA expression profiles pre‐ and post‐osteogenic induction were obtained using microarray essay, and differently expressed miRNAs were verified using quantitative real‐time polymerase chain reaction (qRT‐PCR). The expression of osteogenic proteins was detected using an enzyme‐linked immunosorbent assay. Putative targets of the miRNAs were predicted using online software MiRanda, TargetScan, and miRBase. Eight miRNAs were found differently expressed pre‐ and post‐osteogenic induction, among which four miRNAs (miR‐17, miR‐20a, miR‐20b, and miR‐106a) were up‐regulated and four miRNAs (miR‐31, miR‐125a‐5p, miR‐125b, and miR‐193a) were down‐regulated. qRT‐PCR analysis further confirmed the results. Predicted target genes of the differentially expressed miRNAs based on the overlap from three public prediction algorithms: MiRanda, TargetScan, and miRBase Target have the known functions of regulating stem cell osteogenic differentiation, self‐renewal, signal transduction, and cell cycle control. We identified a group of miRNAs that may play important roles in regulating hADSC cell differentiation toward an osteoblast lineage. Further study of these miRNAs may elucidate the mechanism of hADSC differentiation into adipose tissue, and thus provide basis for tissue engineering. J. Cell. Biochem. 113: 888–898, 2012. © 2011 Wiley Periodicals, Inc.
Uniform two‐class regular partial Steiner triple systems
Authors: Keranen Melissa S. , Kreher Donald L. , Özkan Sibel 
Published: December 2011

AbstractA 2‐class regular partial Steiner triple system is a partial Steiner triple system whose points can be partitioned into 2‐classes such that no triple is contained in either class and any two points belonging to the same class are contained in the same number of triples. It is uniform if the two classes have the same size. We provide necessary and sufficient conditions for the existence of uniform 2‐class regular partial Steiner triple systems.
Comparison of single and joint effects of Zn and Cu in continuous flow and batch reactors
Authors: Şengör Sema Sevinç , Gikas Petros , Moberly James G , Peyton Brent M , Ginn Timothy R 
Published: December 2011

AbstractBACKGROUND: Microbial behavior in batch reactors may be different from that in continuous flow reactors, which is expected to affect microbial response to heavy metal exposure. Four parallel continuous flow reactors and batch growth tests were used to investigate the single and joint toxicity of Zn and Cu to Artrobacter sp. JM018.RESULTS: The results indicated that Cu is more toxic than Zn under all conditions. In the batch reactors, all Zn concentrations showed a stimulatory effect on microbial growth. However in the continuous system, 125 µmol L−1 Zn exposure produced inhibition. In the case of mixed Zn and Cu exposures in the batch system, the presence of Zn reduced the severity of Cu inhibition, with a net impact of reduced growth in all cases, whereas in the continuous system microbial growth and substrate utilization rates sharply decreased and ceased.CONCLUSION: The results clearly showed that growth in batch reactors underestimated significantly the heavy metal inhibition, compared with the continuous system. Therefore, the results of batch reactor tests should not be used directly when heavy metal inhibition is to be interpreted for continuous flow systems. Copyright © 2011 Society of Chemical Industry
The locomotory system of pearlfish Carapus acus: What morphological features are characteristic for highly flexible fishes?
Authors: Schwarz Cathrin , Parmentier Eric , Wiehr Stefan , Gemballa Sven 
Published: December 2011

AbstractThe body curvature displayed by fishes differs remarkably between species. Some nonmuscular features (e.g., number of vertebrae) are known to influence axial flexibility, but we have poor knowledge of the influence of the musculotendinous system (myosepta and muscles). Whereas this system has been described in stiff‐bodied fishes, we have little data on flexible fishes. In this study, we present new data on the musculotendinous system of a highly flexible fish and compare them to existing data on rigid fishes. We use microdissections with polarized light microscopy to study the three‐dimensional anatomy of myoseptal tendons, histology and immunohistology to study the insertion of muscle fiber types into tendons, and μ‐CT scans to study skeletal anatomy. Results are compared with published data from stiff‐bodied fishes. We identify four important morphological differences between stiff‐bodied fishes and Carapus acus: (1) Carapus bears short tendons in the horizontal septum, whereas rigid fishes have elongated tendons. (2) Carapus bears short lateral tendons in its myosepta, whereas stiff‐bodied fishes bear elongated tendons. Because of its short myoseptal tendons, Carapus retains high axial flexibility. In contrast, elongated tendons restrict axial flexibility in rigid fishes but are able to transmit anteriorly generated muscle forces through long tendons down to the tail. (3) Carapus bears distinct epineural and epipleural tendons in its myosepta, whereas these tendons are weak or absent in rigid fishes. As these tendons firmly connect vertebral axis and skin in Carapus, we consider them to constrain lateral displacement of the vertebral axis during extreme body flexures. (4) Ossifications of myoseptal tendons are only present in C. acus and other more flexible fishes but are absent in rigid fishes. The functional reasons for this remain unexplained. J. Morphol., 2012. © 2011 Wiley Periodicals, Inc.
Detection of central nervous system tissue as bovine spongiform encephalopathy specified risk material in traditional Turkish meat products
Authors: Kale Mehmet , Hasırcıoglu Sibel , Ozturk Cagdas , Akcan Kale A Selcen , Dogruer Yusuf 
Published: December 2011

AbstractBACKGROUND: This study used enzyme‐linked immunosorbent assay kits to investigate the presence of central nervous system (CNS) tissue in commercial raw and processed traditional Turkish meat products offered for consumption in various markets.RESULTS: Ninety‐six raw traditional Turkish meat products (32 fresh raw beef patties, 32 cig kofta, 32 pastirma) and 64 processed traditional Turkish meat products (32 doner kebabs and 32 fresh processed beef patties) were analysed. CNS tissue was not found in pastirma, doner kebab, or fresh processed beef patty samples. The levels of CNS contamination in fresh raw beef patties were low (0.1% absorbance standard; 3.1%) and moderate (0.2% absorbance standard; 6.2%). The level of contamination in the cig kofta was low (0.1% absorbance standard; 18.8%).CONCLUSION: CNS tissue was present in all raw traditional Turkish meat products except for pastirma. Copyright © 2011 Society of Chemical Industry
Exploring c‐Met kinase flexibility by sampling and clustering its conformational space
Authors: Asses Yasmine , Venkatraman Vishwesh , Leroux Vincent , Ritchie David W. , Maigret Bernard 
Published: December 2011

AbstractIt is now widely recognized that the flexibility of both partners has to be considered in molecular docking studies. However, the question how to handle the best the huge computational complexity of exploring the protein binding site landscape is still a matter of debate. Here we investigate the flexibility of c‐Met kinase as a test case for comparing several simulation methods. The c‐Met kinase catalytic site is an interesting target for anticancer drug design. In particular, it harbors an unusual plasticity compared with other kinases ATP binding sites. Exploiting this feature may eventually lead to the discovery of new anticancer agents with exquisite specificity. We present in this article an extensive investigation of c‐Met kinase conformational space using large‐scale computational simulations in order to extend the knowledge already gathered from available X‐ray structures. In the process, we compare the relevance of different strategies for modeling and injecting receptor flexibility information into early stage in silico structure‐based drug discovery pipeline. The results presented here are currently being exploited in on‐going virtual screening investigations on c‐Met. Proteins 2012;. © 2011 Wiley Periodicals, Inc.
Railway satellite channel at Ku band and above: Composite dynamic modeling for the design of fade mitigation techniques
Authors: Arapoglou Pantelis‐Daniel , Liolis Konstantinos P. , Panagopoulos Athanasios D. 
Published: December 2011

SUMMARYPast studies on the railway satellite channel (RSC) at Ku band and above consider exclusively the attenuation coming from the metal power arches (PAs) along the railway route, producing significant though deterministic periodical fast fading. Nevertheless, limited attention has been given to model tropospheric effects on the RSC. The present paper takes a more comprehensive view of the RSC by introducing a novel stochastic dynamic model of rain fading in mobile satellite systems on top of the diffraction because of PAs. The proposed approach builds upon well‐established research on rain attenuation time series synthesizers employing stochastic differential equations. It is shown that this propagation tool may provide significant aid, in general, in mobile satellite system simulations and in the design of fade mitigation techniques (FMTs), particularly aiming at the railway scenario. The tool enables the generation of fade events, fade duration statistics, rain attenuation power spectrum and predicting the necessary FMT control loop margin. This is particularly useful for the RSC because most of the proposed FMTs focusing on PAs are not appropriate for compensating atmospheric fading. Copyright © 2011 John Wiley & Sons, Ltd.
Indirect interaction between butterfly species mediated by a shared pupal parasitoid
Authors: van Nouhuys Saskya , Kraft Thomas S. 
Published: December 2011

AbstractIndirect interactions among species can greatly affect their abundances and the structure of the community they live in. Using a field experiment, we tested the hypothesis that congeneric butterfly species interact indirectly through a shared pupal parasitoid. We predicted that symmetrical apparent competition would lead to high parasitism of both species, and the effect would increase with regional butterfly abundance. Instead, parasitism of one host,Melitaea cinxia, was reduced in the presence of the second host,M.athalia. Parasitism ofM.athaliadid not differ whether or notM.cinxiawas present. This pattern did not vary with regional butterfly abundance, though overall rate of parasitism did. Details of the experiment suggest that the apparent commensalism occurred becauseM.cinxiapupae are protected by silk tents whereasM.athaliaare exposed, causing locally foraging parasitoids to favour the more accessible host where the two are present together. The local short‐term apparent commensalism favouringM.cinxiaopposes the landscape scale trend, in which parasitism increases where butterfly density is high. The outcome of this study illustrates short‐term apparent commensalism, that host suitability can depend on relative accessibility, and that indirect interactions occurring at different scales may be in opposition.
Mechanism of mammalian germ cell development: toward assisted new reproductive technologies
Authors: Suzuki Atsushi , Kurihara Yasuyuki , Saga Yumiko 
Published: December 2011

AbstractApproximately 10% of Japanese couples who want to have children experience infertility, and the majority of these individuals have either abnormal egg cell or abnormal sperm development. In addition, currently, there is a low birth rate in many parts of the developed world; therefore, it is critical to elucidate the mechanisms of germ cell development. Thus, the study of assisted reproductive technologies has scientific significance, and is a key to solving infertility problems. This review summarizes the development of mouse germ cells, particularly focusing on the role of Nanos genes, which are essential for the development of mouse germ cells and have been identified as genes that are involved in human infertility. We also briefly introduce a study in which this information is applied to assisted reproductive technologies.
Manipulating basic taste perception to explore how product information affects experience
Authors: Litt Ab , Shiv Baba 
Published: December 2011

AbstractWe introduce a novel physiologically‐based methodology to consumer research—using the glycoprotein miraculin to manipulate the ability to sense and perceive specific taste elements in gustatory experiences. We apply this approach to exploring how information extrinsic (e.g., product reviews) to a product's inherent sensory facets influences reported consumption experiences and experienced utility. Results from two experiments suggest that extrinsic information distorts the basic sensory and perceptual character of consumption experiences, rather than simply biasing self‐reports of the experiences or serving as an independent input to overall taste and utility evaluations. Such evaluations are distorted in the direction of extrinsic product information only when the ability to actually perceive the experience as being consistent with the extrinsic signal is not disrupted by miraculin. Conversely, disruption by miraculin of the ability to perceive an experience as being consistent with an extrinsic signal ablates or reverses such effects. Implications, applications to brands and branding, and other possible research directions for the miraculin taste‐manipulation methodology are also discussed.
Are exchange rates serially correlated? New evidence from the Euro FX markets
Authors: Cheung Adrian Wai‐Kong , Su Jen‐Je , Choo Astrophel Kim 
Published: December 2011

AbstractThis paper examines the serial uncorrelatedness hypothesis in the Euro FX markets by testing for autocorrelation in daily FX returns of 82 countries over the period of 1999–2010. We use three newly developed tests that are robust to conditional heteroskedasticity of unknown forms and that do not choose a lag parameter arbitrarily. They are Escanciano & Lobato (2009)'s automatic Box–Pierce Qp test, Nankervis & Savin (2010)'s generalized Andrews–Ploberger test and Deo (2000)'s robust Durlauf test. We find no significant autocorrelation in the FX returns of around 58 to 62 countries, suggesting that majority of the Euro FX markets are weak‐form efficient.
Science, Values and People: The Three Factors that Will Define the Next Generation of International Conservation Agreements
Authors: Gillespie Alexander 
Published: December 2011

AbstractThis paper is concerned with three emerging issues that define the way in which international conservation law moves forward in the coming decades. The three issues are those related to the use of science to frame regimes; the use of philosophy to examine the values of what is trying to be achieved; and the use of politics to ensure that local communities are linked to conservation efforts. Consideration of each of these three areas is relatively recent, none of them having being at the forefront of conservation considerations of international importance in the past. In the future, this is likely to change.
Biogeography and phylogenetic diversity of a cluster of exclusively marine myxobacteria
Authors: Brinkhoff Thorsten , Fischer Doreen , Vollmers John , Voget Sonja , Beardsley Christine , Thole Sebastian , Mussmann Marc , Kunze Brigitte , Wagner-Döbler Irene , Daniel Rolf , Simon Meinhard 
Published: December 2011

Abstract
Myxobacteria are common in terrestrial habitats and well known for their formation of fruiting bodies and production of secondary metabolites. We studied a cluster of myxobacteria consisting only of sequences of marine origin (marine myxobacteria cluster, MMC) in sediments of the North Sea. Using a specific PCR, MMC sequences were detected in North Sea sediments down to 2.2 m depth, but not in the limnetic section of the Weser estuary and other freshwater habitats. In the water column, this cluster was only detected on aggregates up to a few meters above the sediment surface, but never in the fraction of free-living bacteria. A quantitative real-time PCR approach revealed that the MMC constituted up to 13% of total bacterial 16S rRNA genes in surface sediments of the North Sea. In a global survey, including sediments from the Mediterranean Sea, the Atlantic, Pacific and Indian Ocean and various climatic regions, the MMC was detected in most samples and to a water depth of 4300 m. Two fosmids of a library from sediment of the southern North Sea containing 16S rRNA genes affiliated with the MMC were sequenced. Both fosmids have a single unlinked 16S rRNA gene and no complete rRNA operon as found in most bacteria. No synteny to other myxobacterial genomes was found. The highest numbers of orthologues for both fosmids were assigned to Sorangium cellulosum and Haliangium ochraceum. Our results show that the MMC is an important and widely distributed but largely unknown component of marine sediment-associated bacterial communities.
Minimal cut sets in a metabolic network are elementary modes in a dual network
Authors: Ballerstein Kathrin , von Kamp Axel , Klamt Steffen , Haus Utz-Uwe 
Published: December 2011

Abstract
Motivation: Elementary modes (EMs) and minimal cut sets (MCSs) provide important techniques for metabolic network modeling. Whereas EMs describe minimal subnetworks that can function in steady state, MCSs are sets of reactions whose removal will disable certain network functions. Effective algorithms were developed for EM computation while calculation of MCSs is typically addressed by indirect methods requiring the computation of EMs as initial step.
Results: In this contribution, we provide a method that determines MCSs directly without calculating the EMs. We introduce a duality framework for metabolic networks where the enumeration of MCSs in the original network is reduced to identifying the EMs in a dual network. As a further extension, we propose a generalization of MCSs in metabolic networks by allowing the combination of inhomogeneous constraints on reaction rates. This framework provides a promising tool to open the concept of EMs and MCSs to a wider class of applications.
Contact: utz-uwe.haus@math.ethz.ch; klamt@mpi-magdeburg.mpg.de
Supplementary information: Supplementary data are available at Bioinformatics online.
Targeted MRI Contrast Agents for Pediatric Hepatobiliary Disease
Authors: Courtier Jesse L. , Perito Emily R. , Rhee Sue , Tsai Patrika , Heyman Melvin B. , MacKenzie John D. 
Published: December 2011

ABSTRACTNew options are available for the magnetic resonance imaging (MRI) assessment of pediatric hepatobiliary disease. This article describes the potential utility for MRI with contrast agents tailored for hepatobiliary imaging. MRI contrast agents that preferentially target the liver may be helpful in characterizing liver masses and bile duct abnormalities in select children. The imaging approach is noninvasive and relatively rapid to perform. It also provides anatomic and functional information and is a radiation‐free alternative to other imaging strategies. This relatively new imaging procedure is placed in the context of more established imaging modalities. The pharmacokinetics, technical considerations, and potential applications of these hepatobiliary‐specific contrast agents also are discussed.