bluuebunny/crossref_metadata_2025_split huggingface dataset:
Small‐group, computer‐mediated argumentation in middle‐school classrooms: The effects of gender and different types of online teacher guidance
Authors: Asterhan Christa S. C. , Schwarz Baruch B. , Gil Julia 
Published: April 2011

Background.  Research has shown the importance of careful teacher support during collaborative group work to promote productive discourse between students (Webb, 2009). However, this research has traditionally focused on face‐to‐face communication. The role of online teacher guidance of small‐group computer‐mediated discussions has received little attention, especially in secondary school classroom settings. Researchers of computer‐supported collaborative learning (CSCL), on the other hand, have traditionally focused on software‐embedded features, such as scripts, to support a‐synchronous peer dialogue, and less so on human guidance of synchronous group discussions.Aims.  The main aim of the present in vivo, experimental study is to examine whether online teacher guidance can improve the quality of small‐group synchronous discussions, and whether different types of guidance (epistemic or interaction guidance) affect these discussions differently, when compared to an unguided condition. The second goal of this study is to explore potential differences between all‐female and all‐male discussion groups.Sample.  Eighty‐two 9th graders (three classrooms) and six teachers from a rural high school in Israel.Results.  Whereas epistemic guidance only improved aspects of the argumentative quality of the discussion, interaction guidance only improved aspects of collaboration. Discussions of all‐girls groups scored higher on aspects of collaboration and argumentative quality, compared to all‐boys groups.Conclusions.  The findings show that teacher guidance of synchronous, online discussions in classrooms is realizable and reasonably reaches its intended goals. Training should be focused on acquiring various guidance strategies to augment their beneficial effects. Furthermore, future research should pay more attention to potential gender differences in peer‐to‐peer argumentation.
The relative importance of two different mathematical abilities to mathematical achievement
Authors: Nunes Terezinha , Bryant Peter , Barros Rossana , Sylva Kathy 
Published: April 2011

Background.  Two distinct abilities, mathematical reasoning and arithmetic skill, might make separate and specific contributions to mathematical achievement. However, there is little evidence to inform theory and educational practice on this matter.Aims.  The aims of this study were (1) to assess whether mathematical reasoning and arithmetic make independent contributions to the longitudinal prediction of mathematical achievement over 5 years and (2) to test the specificity of this prediction.Sample.  Data from Avon Longitudinal Study of Parents and Children (ALSPAC) were available on 2,579 participants for analyses of KS2 achievement and on 1,680 for the analyses of KS3 achievement.Method.  Hierarchical regression analyses were used to assess the independence and specificity of the contribution of mathematical reasoning and arithmetic skill to the prediction of achievement in KS2 and KS3 mathematics, science, and English. Age, intelligence, and working memory (WM) were controls in these analyses.Results.  Mathematical reasoning and arithmetic did make independent contributions to the prediction of mathematical achievement; mathematical reasoning was by far the stronger predictor of the two. These predictions were specific in so far as these measures were more strongly related to mathematics than to science or English. Intelligence and WM were non‐specific predictors; intelligence contributed more to the prediction of science than of maths, and WM predicted maths and English equally well.Conclusions.  There is clear justification for making a distinction between mathematical reasoning and arithmetic skills. The implication is that schools must plan explicitly to improve mathematical reasoning as well as arithmetic skills.
THE MATHER MEASURE AND A LARGE DEVIATION PRINCIPLE FOR THE ENTROPY PENALIZED METHOD
Authors: GOMES D. A. , LOPES A. O. , MOHR J. 
Published: April 2011

We present the rate function and a large deviation principle for the entropy penalized Mather problem when the Lagrangian is generic (it is known that in this case the Mather measure μ is unique and the support of μ is the Aubry set). We assume the Lagrangian L(x, v), with x in the torus 𝕋Nand v∈ℝN, satisfies certain natural hypotheses, such as superlinearity and convexity in v, as well as some technical estimates. Consider, for each value of ϵ and h, the entropy penalized Mather problem [Formula: see text] where the entropy S is given by [Formula: see text], and the minimization is performed over the space of probability densities μ(x, v) on 𝕋N×ℝNthat satisfy the discrete holonomy constraint ∫𝕋N×ℝNφ(x + hv) - φ(x) dμ = 0. It is known [17] that there exists a unique minimizing measure μϵ, hwhich converges to a Mather measure μ, as ϵ, h→0. In the case in which the Mather measure μ is unique we prove a Large Deviation Principle for the limit limϵ, h→0ϵ ln μϵ, h(A), where A ⊂ 𝕋N×ℝN. In particular, we prove that the deviation function I can be written as [Formula: see text], where ϕ0is the unique viscosity solution of the Hamilton – Jacobi equation, [Formula: see text]. We also prove a large deviation principle for the limit ϵ→ 0 with fixed h.Finally, in the last section, we study some dynamical properties of the discrete time Aubry–Mather problem, and present a proof of the existence of a separating subaction.
HUMAN REFLEXIVE RESPONSE AND ITS OBJECTIVE FUNCTION REGARDING BALANCE RECOVERY FROM PERTURBATION DURING WALKING
Authors: YIKEMOTO YU , YU WENWEI , ACHARYA U. RAJENDRA 
Published: April 2011

Balance recovery from perturbation plays a crucial role in preventing people from falling during walking. Understanding the underlying mechanism of balance recovery during walking could not only bring new insights into the motor control field, but also benefit the development of walking assist systems for daily living environment, where perturbations to walking are frequently caused by slips, uneven terrain, slopes, obstacles, etc.It is evident that humans can cope with such perturbations, especially when the perturbations cannot be predicted or perceived in advance, by means of reflexes, which cause relatively fixed, unconscious muscular response patterns to perturbations within a short period of time ranging from several tens of ms to 200 ms. However, except for several hypotheses about the underlying neural mechanisms of the reflexes during walking, there is no widely accepted unified theory.In our previous study, a muscular-reflexive pattern was defined using muscle activity recorded during reflexive responses to slip perturbation. This is one important step toward the understanding of the underlying mechanism, since the pattern could serve as the quantitative target in pursuit of the underlying mechanism. We can speculate that this pattern is the optimal balance recovery behavior to human muscular-skeletal system, as a result of long evolution; however, before we use this target to guide our pursuit, we should first prove its optimality, while making clear the objective functions for balance recovery and the effect of morphological factors.Our approach includes (1) defining objective functions for balance recovery from a slip perturbation during walking; (2) using a bio-mimetic human walking simulator to perform evaluation according to the objective functions; (3) employing a genetic algorithm (GA) to search the optimal solutions, for different objective functions.Results showed that the muscular-reflexive pattern is optimal to the balance recovery from slip perturbation during walking, in terms of a hybrid evaluation measure (HEM), which takes both static and dynamic aspects of balance recovery into consideration.
Episodic fluvial incision of rivers and rock uplift in the Himalaya and Transhimalaya
Authors: Dortch Jason M. , Dietsch Craig , Owen Lewis A. , Caffee Marc W. , Ruppert Kelly 
Published: April 2011

Abstract:

Seventeen strath terraces in northern India were dated using
10
Be surface exposure methods; ages range from
c
. 7 to
c
. 735 ka and provide fluvial incision rates of 0.02 ± 0.003 to 2.6 ± 1.9 mm a
−1
. On the northern side of the Ladakh Range, incision rates are
c
. 1 mm a
−1
; in the northern Zanskar Range they are ≤0.06 ± 0.005 mm a
−1
. New and published incision rates in southernmost Lahul range from 0.1 ± 0.02 to 13.2 ± 6.2 mm a
−1
; rates for ages >35 ka are ≤0.4 ± 0.2 mm a
−1
. Across the Himalaya and Transhimalaya, Holocene fluvial incision rates range from
c
. 0.02 to
c
. 26.0 mm a
−1
, whereas Pleistocene incision rates are ≤5 mm a
−1
. Many of the Holocene incision rates exceed exhumation rates, whereas Pleistocene incision rates are comparable with exhumation rates. This suggests that long-term fluvial incision is in dynamic steady state with exhumation. The temporal pattern for rates of fluvial incision is probably controlled by episodic incision linked to significant precipitation changes throughout the Quaternary, suggesting that strath terraces with ages >35 ka can be used for assessing long-term rates of rock uplift. In contrast, rates of fluvial incision based on Late Glacial and Holocene strath terraces reflect changes in monsoon intensity and deglaciation events. By determining ages for multiple samples on flights of strath terraces, it is possible to document changes in incision rate, assess whether post-abandonment transient shielding has occurred, and help elucidate tectonic v. climatic controls on their formation.

Supplementary material:

Tables (DS1–4) for previously published data and recalculated ages for strath terraces, and figures (DS1 and DS2) showing plots of incision rates against time for the Himalaya and Transhimalaya are available at
http://www.geolsoc.org.uk/SUP18454
.
Assessing the catastrophic break-up of Briksdalsbreen, Norway, associated with rapid climate change
Authors: Hart Jane K. , Rose Kathryn C. , Waller Richard I. , Vaughan-Hirsch David , Martinez Kirk 
Published: April 2011

Abstract:

Recent research has raised concerns about the potential influence of rapid climate change on the stability of major ice sheets. The behaviour of glaciers is determined largely by the processes and conditions operating at their base. Technological advances have allowed these factors to be examined and their contribution to ice flow constrained. This study investigated the rapid disintegration of an aquatic based Norwegian glacier, through the study of boreholes, video, ground-penetrating radar, differential global positioning system, bathymetry and Glacsweb wireless probes. Briksdalsbreen retreated dramatically between 2000 and 2007, with
c
. 56 × 10
5
m
3
of ice lost from the glacier tongue, equivalent to a rate of 70 m a
−1
. This was due to the combined effect of higher summer temperatures, decreased precipitation (resulting from a negative phase of the North Atlantic Oscillation) and increased fracturing of the glacier tongue. The enlargement of a proglacial lake played a key role in Brikdalsbreen's rapid retreat, allowing calving events and promoting crevassing and fluctuating water contents at the glacier margin. We suggest that hydro-fracturing was the dominant mechanism responsible for generating more crevasses each year, which facilitated the development of an efficient englacial drainage system. This fed increasing quantities of water to the bed, where it was stored in subglacial cavities and transferred through a distributed (‘slow') drainage system. However, despite this increase in subglacial water content, ice velocities remained constant during the break-up. Comparisons are made between the processes observed at Briksdalsbreen and those associated with the acceleration and rapid retreat of Greenland's tidewater glaciers.
A refined chronology for the Cambrian succession of southern Britain
Authors: Harvey Thomas H.P. , Williams Mark , Condon Daniel J. , Wilby Philip R. , Siveter David J. , Rushton Adrian W.A. , Leng Melanie J. , Gabbott Sarah E. 
Published: April 2011

Abstract:

Three dated (U–Pb, zircon) ash beds from biostratigraphically constrained Avalonian successions of Shropshire (England) and Pembrokeshire (Wales) delimit the traditional ‘Lower'–‘Middle' Cambrian boundary and resolve a problematic regional correlation. In Shropshire, a date of 514.45 ± 0.36 [0.81 including tracer calibration and
238
U decay constant errors] Ma from near the top of the Lower Comley Sandstone Formation provides a maximum age for the boundary between Cambrian Stages 3 and 4, and a date of 509.10 ± 0.22 [0.77 including tracer calibration and
238
U decay constant errors] Ma from the basal Quarry Ridge Grits, Upper Comley Sandstone Formation, provides a minimum age for the boundary between Cambrian Stages 4 and 5 (and thus Series 2 and 3). These dates offer a calibration of early metazoan evolution by directly constraining the age of the intervening Comley Limestones, which contain diverse small shelly fossils in addition to trilobites, and also a key early occurrence of exceptional, three-dimensionally preserved arthropods. In Pembrokeshire, an ash bed from the Caerfai Bay Shales Formation dates to 519.30 ± 0.23 [0.77 including tracer calibration and
238
U decay constant errors] Ma, equivalent to a horizon low in the Lower Comley Sandstone Formation of Shropshire, possibly around the level at which trilobites make their first local appearance.

Supplementary material:

Appendix 1, a table of isotope data, is available at
http://www.geolsoc.org.uk/SUP18444
.
Geochemistry and U–Pb dating of felsic volcanic rocks in the Riotinto–Nerva unit, Iberian Pyrite Belt, Spain: crustal thinning, progressive crustal melting and massive sulphide genesis
Authors: Valenzuela Alfonso , Donaire Teodosio , Pin Christian , Toscano Manuel , Hamilton Michael A. , Pascual Emilio 
Published: April 2011

Abstract:

We present new geochemical, Sm–Nd and U–Pb data on the felsic volcanic rocks containing the world-class volcanic-hosted massive sulphide deposits in the Riotinto–Nerva unit, Iberian Pyrite Belt, Spain. Three new U–Pb ages from older plagioclase–quartz-phyric dacites and plagioclase-phyric rhyolites to youngest plagioclase–quartz-phyric rhyolites indicate a time span for felsic volcanism ranging from 351.5 ± 0.4 to 345.7 ± 0.6 Ma. The youngest felsic rocks exhibit lower ε
Nd
, as well as contrasting Ti, Sr, Zr, Hf and Eu/Eu* values. We interpret that in the Riotinto–Nerva unit crustal melting successively affected shallower, more evolved horizons in the crust. Progressive crustal melting is consistent with current interpretations of the Iberian Pyrite Belt in terms of a late Devonian–Early Carboniferous transtensional setting, coupled with underplating by basic magma. We suggest that low ε
Nd
, evolved crustal magmatism could be used as a proxy in studies of the genesis of these and possibly other Phanerozoic massive sulphide deposits.

Supplementary material:

Details of the analytical methods and whole-rock data for basalts are available at
http://www.geolsoc.org.uk/SUP18452
.
Submarine slope degradation and aggradation and the stratigraphic evolution of channel–levee systems
Authors: Hodgson D.M. , Di Celma C.N. , Brunt R.L. , Flint S.S. 
Published: April 2011

Abstract:
Two seismic-scale submarine channel–levee systems exposed in the Karoo Basin, South Africa provide insights into slope conduit evolution. Component channel fills in a levee-confined channel system (Unit C) and an entrenched channel system (Unit D) follow common stacking patterns; initial horizontal stacking (lateral migration) is followed by vertical stacking (aggradation). This architecture is a response to an equilibrium profile shift from low accommodation (slope degradation, composite erosion surface formation, external levee development, sediment bypass) through at-grade conditions (horizontal stacking and widening) to high accommodation (slope aggradation, vertical stacking, internal levee development). This architecture is likely common to other channel–levee systems.

Supplementary material:

A detailed correlation panel (presented schematically in Figure
2
) is available at
www.geolsoc.org.uk/SUP18456
.
The significance of hiatal surfaces in coal seams
Authors: Jerrett R.M. , Davies R.C. , Hodgson D.M. , Flint S.S. , Chiverrell R.C. 
Published: April 2011

Abstract:
A widespread misconception is that coals correspond to single palaeo-peat bodies, which represent continuous and time-invariant records of peat accumulation. Evidence for the occurrence of intra-seam hiatal surfaces within datasets from bituminous coals, lignites and modern peats suggests that existing depositional models for peat and coal require modification. Recognition that coals may represent a succession of stacked mires separated by hiatal surfaces has implications for palaeoenvironmental and sequence stratigraphic studies that assume a continuous record of peat accumulation, as well as for the prediction of whole-seam composition and thickness trends.
Abstract ES2-2: DNA Repair and Breast Cancer: Therapeutic Opportunities
Authors: Silver DP 
Published: April 2011

Abstract
The recognition that BRCA1 and BRCA2 have roles in DNA repair and that defects in either of these genes leads to specific therapeutic vulnerabilities has increased our understanding of why some tumors are susceptible to chemotherapy. Mutations in BRCA1 or BRCA2 cause defective homologous recombination, one of the fundamental systems for DNA repair. Preclinical modeling, clinical trials, and observations about acquired chemotherapy resistance all suggest strongly that mutations in BRCA1 or BRCA2 also sensitize tumors to the platinum agents, cisplatinum and carboplatinum, underscoring the important role of homologous recombination in response to these agents. Further, data concerning the increased dependence of cells with defects in another DNA repair system, base excision repair, on homologous recombination has led to the development of PARP inhibitors. These new therapeutic agents exploit this relationship between these DNA repair pathways and underscore the utility of synthetic lethality as a concept in drug development. These insights as they apply to breast cancer therapy will be discussed.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr ES2-2.
Abstract ES3-3: Management of Women with a High Predisposition to Breast Cancer: Standard of Care
Authors: Domchek SM 
Published: April 2011

Abstract
Women who have inherited germ line mutations in BRCA1 and BRCA2 are at significantly increased risk for breast and ovarian cancer. Fortunately, our understanding of the management of BRCA1 and BRCA2 mutation carriers has increased significantly in the 15 years since these genes were identified. There have been improvements in genetic testing techniques resulting in fewer “missed” BRCA1 and BRCA2 mutations, as well as a better understanding of the risks of these mutations. Incorporating breast MRI into screening results in earlier detection of breast cancer. Prophylactic mastectomy significantly reduces breast cancer risk, while improvements in reconstructive surgery allow women more options. Risk reducing salpingo-oophorectomy in BRCA1/2 mutation carriers decreases breast cancer risk, ovarian cancer risk and improves breast cancer specific-, ovarian cancer specific-and overall survival. Emerging data suggest that BRCA1/2 mutation testing can play a role in newly diagnosed breast cancer, particularly from the standpoint of surgical decision making. Finally, knowledge of BRCA1 and BRCA2 mutation status has the potential to impact decisions on systemic therapy as will be reviewed.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr ES3-3.
Abstract ES4-1: Statistical Challenges in Predictive and Prognostic Biomarker Studies: How To Avoid Wasting Your Time and Specimens
Authors: McShane LM 
Published: April 2011

Abstract
A better understanding of tumor biology through identification of specific biological characteristics of tumor and host that predict tumor behavior and responsiveness to therapy will be essential for the discovery of new therapies and for optimization of cancer care for individual patients. Progress in identifying promising biomarkers in correlative studies and moving them to the clinic has been slow. Many correlative studies are conducted without clearly specified hypotheses, have poor statistical designs, use assays that are not standardized or lack reproducibility, and often employ inappropriate or misleading statistical analysis approaches. Common statistical problems include underpowered studies or overly optimistic reporting of effect sizes and significance levels due to multiple testing, subset analyses, cutpoint optimization, and model overfitting. For studies aiming to a assess a biomarker's ability to guide treatment decisions, the importance of appropriate control groups and the potential for confounding of prognostic and predictive effects have been underappreciated. Compounding these problems, many correlative studies have not been reported in a rigorous fashion, and published articles often lack sufficient information to allow adequate assessment of the quality of the study or the generalizability of the results. Suggestions are provided for how to avoid some of the common statistical pitfalls, how to identify problematic studies, and how to report correlative studies to maximize the interpretability and usefulness of the results.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr ES4-1.
Abstract ES4-2: The importance of Technical Validation
Authors: Reis-Filho JS 
Published: April 2011

Abstract
The development of biomarkers for the diagnosis and classification of breast cancers and stratification of breast cancer patients into clinically meaningful groups is one of the lynchpins of individualised medicine. The correct and robust assignment of patients into subgroups of therapeutic relevance is of utmost importance. In breast cancer management, this is currently performed through the analyses of a few immunohistochemical markers (e.g. oestrogen receptor, progesterone receptor and HER2), fluorescence and/or chromogenic in situ hybridisation, protein analysis of lysates, and quantitative real-time PCR. It has become patently clear, however, that these markers are not sufficient for the potential of individualised therapy to be realised. With the advent of high throughput technologies, fundamental and translational research approaches have provided a wealth of data on diagnostic markers, potential prognostic and predictive markers, and therapeutic targets, which ultimately will need to be incorporated in clinical practice. Some of the major challenges in this process are to determine the accuracy of the research hypothesis, the exclusion of potential biases, and to define whether the reagents and methodologies are fit for purpose. This requires a thorough assessment of the accuracy, robustness and reproducibility of the markers and the methods for their analysis. For instance, immunohistochemistry has become one of the major tools for the identification of expression of potential markers in cancer tissues; albeit at first glance trivial to perform, immunohistochemical analysis can be affected by numerous parameters that can affect its accuracy. Likewise, several approaches for the identification of molecular subgroups by gene expression profiling have been shown not to assign the same patients into the same molecular subgroups consistently. Interpretation of in situ hybridisation is also fraught with difficulties and discrepancies have often been attributed to intra-tumour heterogeneity rather than technical variation. The challenges for the assessment and validation of biomarkers in human tissues and the approaches to overcome them will be discussed.
Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr ES4-2.