67 research outputs found

    Comprehension, Diagram Analysis, Integration, and Interest: A Cross-Sectional Analysis

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    The current study examines a multidimensional set of outcome variables to understand whether different pre-reading scaffolds influence students’ text comprehension, diagram analysis, text integration, and interest; and investigates these constructs cross-sectionally to identify any progression as students move across grades. One-hundred fifty-six 3rd through 6th grade students enrolled in a public laboratory school were randomly assigned to one of three pre-reading conditions intended to activate or build students’ topic knowledge. Students completed a series of before, during, and after reading activities while engaging with grade appropriate texts about the topics of ecosystems and living things. Results indicate that there were no significant differences between the three pre-reading conditions on any of the four constructs of interest. Students across grade levels performed well on multiple-choice comprehension questions, but not as well on diagram analysis questions or an open-ended integration task. Implications and future directions are discussed

    MODELING MULTIPLE SOURCE USE: USING LEARNER CHARACTERISTICS AND SOURCE USE BEHAVIORS TO PREDICT RESPONSE QUALITY

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    Multiple source use (MSU) has been identified as both a critical competency and a key challenge for today's students, living in the digital age (Goldman & Scardamalia, 2013b). Theoretical models of multiple source use provide insights into how the MSU process unfolds and identify points at which students may encounter challenges (i.e., in source selection, processing, and evaluation, Rouet & Britt). However, understandings of MSU have been limited by two gaps in the literature. First, while points of challenge in students' MSU process have been examined independently, comprehensive models considering the joint role of source selection, processing, and evaluation in task performance have not been fully investigated. Further, while research on MSU has focused on students' behaviors when engaging with texts, individual difference factors have been considered only to a limited extent, despite their theorized importance (Rouet, 2006). The purpose of the present study was to examine the extent to which multiple source use behaviors (i.e., source selection, processing, and evaluation) and learner characteristics (i.e., prior knowledge, domain general source evaluation behaviors, stances on the target issue) predicted open-ended task performance, both independently and in conjunction with one another. Participants were 197 undergraduate students, asked to complete measures assessing their prior knowledge, stances on the Arab Spring in Egypt, the topic of the task, and domain general source evaluation behaviors. Then, participants were tasked with using a library of six sources to respond to a controversial prompt about a contemporary event (i.e., Arab Spring in Egypt). While students engaged with sources, log data of source use were collected (e.g., number of sources accessed, time on texts) and participants were asked to rate sources accessed in terms of trustworthiness, usefulness, and interestingness. Four indices were used to assess open-ended response quality: (a) word count, (b) the number of arguments included in students' responses, (c) scores on the SOLO taxonomy (Biggs & Collis, 1982), reflecting the extent to which students' responses integrated and evaluated information presented across texts, and (d) the number of citations in students' answers. Key findings included the role of students' ratings of source interestingness and time on texts as predictive of open-ended task performance. Further, students' accessing of document information about sources (e.g., author credentials that may aid in source evaluation, Britt & Aglinskas, 2002) and trustworthiness evaluations were found to be associated with SOLO scores. Overall, as compared to multiple source use behaviors, learner characteristics were found to have a more limited effect on task performance. Findings are discussed and implications for theoretical conceptions of multiple source use and instructional practice are presented

    Shifting attention in viewer- and object-based reference frames after unilateral brain injury

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    The aims of the present study were to investigate the respective roles that object- and viewer-based reference frames play in reorienting visual attention, and to assess their influence after unilateral brain injury. To do so, we studied 16 right hemisphere injured (RHI) and 13 left hemisphere injured (LHI) patients. We used a cueing design that manipulates the location of cues and targets relative to a display comprised of two rectangles (i.e., objects). Unlike previous studies with patients, we presented all cues at midline rather than in the left or right visual fields. Thus, in the critical conditions in which targets were presented laterally, reorienting of attention was always from a midline cue. Performance was measured for lateralized target detection as a function of viewer-based (contra- and ipsilesional sides) and object-based (requiring reorienting within or between objects) reference frames. As expected, contralesional detection was slower than ipsilesional detection for the patients. More importantly, objects influenced target detection differently in the contralesional and ipsilesional fields. Contralesionally, reorienting to a target within the cued object took longer than reorienting to a target in the same location but in the uncued object. This finding is consistent with object-based neglect. Ipsilesionally, the means were in the opposite direction. Furthermore, no significant difference was found in object-based influences between the patient groups (RHI vs. LHI). These findings are discussed in the context of reference frames used in reorienting attention for target detection

    Hepatocellular Carcinoma and Nuclear Paraspeckles: Induction in Chemoresistance and Prediction for Poor Survival

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    Background/Aims: Hepatocellular carcinoma (HCC) represents the second most common cause of cancer-related deaths worldwide, not least due to its high chemoresistance. The long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1), localised in nuclear paraspeckles, has been shown to enhance chemoresistance in several cancer types. Since data on NEAT1 in HCC chemosensitivity are completely lacking and chemoresistance is linked to poor prognosis, we aimed to study NEAT1 expression in HCC chemoresistance and its link to HCC prognosis. Methods: NEAT1 expression was determined in either sensitive, or sorafenib, or doxorubicin resistant HepG2, PLC/PRF/5, and Huh7 cells by qPCR. Paraspeckles were detected by immunostaining of paraspeckle component 1 (PSPC1) in cell culture and in a cohort of HCC patients. PSPC1 expression was correlated with clinical data. The expression of transcript variants of NEAT1 and transcripts encoding the paraspeckle-associated proteins was analysed in the TCGA liver cancer data set. Results: NEAT1 was overexpressed in all three sorafenib and doxorubicin resistant cell lines. Paraspeckles were present in all chemoresistant cells, whereas no signal was detected in the sensitive cells. Expression of NEAT1 transcripts as well as transcripts encoding PSPC1, NONO, and RBM14 was increased in tumour tissue. Expression of PSPC1, NONO, and RBM14 transcripts was significantly associated with poor survival, whereas NEAT1 expression was not. Immunohistochemical analysis revealed that nuclear and cytoplasmic PSPC1-positivity was significantly associated with shorter overall survival of HCC patients. Conclusion: Our data show an induction of NEAT1 in HCC chemoresistance and a high correlation of transcripts encoding paraspeckle-associated proteins with poor survival in HCC. Therefore, NEAT1, PSPC1, NONO, and RBM14 might be promising targets for novel HCC therapies, and the paraspeckle-associated proteins might be clinical markers and predictors for poor survival in HCC

    The mRNA-binding Protein TTP/ZFP36 in Hepatocarcinogenesis and Hepatocellular Carcinoma

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    Hepatic lipid deposition and inflammation represent risk factors for hepatocellular carcinoma (HCC). The mRNA-binding protein tristetraprolin (TTP, gene name ZFP36) has been suggested as a tumor suppressor in several malignancies, but it increases insulin resistance. The aim of this study was to elucidate the role of TTP in hepatocarcinogenesis and HCC progression. Employing liver-specific TTP-knockout (lsTtp-KO) mice in the diethylnitrosamine (DEN) hepatocarcinogenesis model, we observed a significantly reduced tumor burden compared to wild-type animals. Upon short-term DEN treatment, modelling early inflammatory processes in hepatocarcinogenesis, lsTtp-KO mice exhibited a reduced monocyte/macrophage ratio as compared to wild-type mice. While short-term DEN strongly induced an abundance of saturated and poly-unsaturated hepatic fatty acids, lsTtp-KO mice did not show these changes. These findings suggested anti-carcinogenic actions of TTP deletion due to effects on inflammation and metabolism. Interestingly, though, investigating effects of TTP on different hallmarks of cancer suggested tumor-suppressing actions: TTP inhibited proliferation, attenuated migration, and slightly increased chemosensitivity. In line with a tumor-suppressing activity, we observed a reduced expression of several oncogenes in TTP-overexpressing cells. Accordingly, ZFP36 expression was downregulated in tumor tissues in three large human data sets. Taken together, this study suggests that hepatocytic TTP promotes hepatocarcinogenesis, while it shows tumor-suppressive actions during hepatic tumor progression

    Bacteria-inducing legume nodules involved in the improvement of plant growth, health and nutrition

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    Bacteria-inducing legume nodules are known as rhizobia and belong to the class Alphaproteobacteria and Betaproteobacteria. They promote the growth and nutrition of their respective legume hosts through atmospheric nitrogen fixation which takes place in the nodules induced in their roots or stems. In addition, rhizobia have other plant growth-promoting mechanisms, mainly solubilization of phosphate and production of indoleacetic acid, ACC deaminase and siderophores. Some of these mechanisms have been reported for strains of rhizobia which are also able to promote the growth of several nonlegumes, such as cereals, oilseeds and vegetables. Less studied are the mechanisms that have the rhizobia to promote the plant health; however, these bacteria are able to exert biocontrol of some phytopathogens and to induce the plant resistance. In this chapter, we revised the available data about the ability of the legume nodule-inducing bacteria for improving the plant growth, health and nutrition of both legumes and nonlegumes. These data showed that rhizobia meet all the requirements of sustainable agriculture to be used as bio-inoculants allowing the total or partial replacement of chemicals used for fertilization or protection of crops

    First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring

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    The Event Horizon Telescope observed the horizon-scale synchrotron emission region around the Galactic center supermassive black hole, Sagittarius A* (Sgr A*), in 2017. These observations revealed a bright, thick ring morphology with a diameter of 51.8 ± 2.3 μas and modest azimuthal brightness asymmetry, consistent with the expected appearance of a black hole with mass M ≈ 4 × 106 M ⊙. From these observations, we present the first resolved linear and circular polarimetric images of Sgr A*. The linear polarization images demonstrate that the emission ring is highly polarized, exhibiting a prominent spiral electric vector polarization angle pattern with a peak fractional polarization of ∼40% in the western portion of the ring. The circular polarization images feature a modestly (∼5%–10%) polarized dipole structure along the emission ring, with negative circular polarization in the western region and positive circular polarization in the eastern region, although our methods exhibit stronger disagreement than for linear polarization. We analyze the data using multiple independent imaging and modeling methods, each of which is validated using a standardized suite of synthetic data sets. While the detailed spatial distribution of the linear polarization along the ring remains uncertain owing to the intrinsic variability of the source, the spiraling polarization structure is robust to methodological choices. The degree and orientation of the linear polarization provide stringent constraints for the black hole and its surrounding magnetic fields, which we discuss in an accompanying publication

    Auditory priming of frequency and temporal information: Effects of lateralised presentation

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    Asymmetric distribution of function between the cerebral hemispheres has been widely investigated in the auditory modality. The current approach borrows heavily from visual localÁglobal research in an attempt to determine whether, as in vision, localÁglobal auditory processing is lateralised. In vision, lateralised localÁ global processing likely relies on spatial frequency information. Drawing analogies between visual spatial frequency and auditory dimensions, two sets of auditory stimuli were developed. In the highÁlow stimulus set we manipulate frequency information, and in the fastÁslow stimulus set we manipulate temporal information. The fastÁslow stimuli additionally mimic visual hierarchical stimulus structure, in which the arrangement of local patterns determines the global pattern. Unlike previous auditory stimuli, the current stimulus sets contain the experimental flexibility of visual localÁglobal hierarchical stimuli allowing independent manipulation of structural levels. Previous findings of frequency and temporal range priming were replicated. Additionally, by presenting stimuli monaurally, we found that priming of frequency ranges (but not temporal ranges) was found to vary by ear, supporting the contention that the hemispheres asymmetrically retain traces of prior frequency processing. These results contribute to the extensive literature revealing cerebral asymmetries for the processing of frequency information, and extend those results to the realm of priming

    Visual hemispatial neglect, re-assessed

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    Increased computer use in clinical settings offers an opportunity to develop new neuropsychological tests that exploit the control computers have over stimulus dimensions and timing. However, before adopting new tools, empirical validation is necessary. In the current study, our aims were twofold: to describe a computerized adaptive procedure with broad potential for neuropsychological investigations, and to demonstrate its implementation in testing for visual hemispatial neglect. Visual search results from adaptive psychophysical procedures are reported from 12 healthy individuals and 23 individuals with unilateral brain injury. Healthy individuals reveal spatially symmetric performance on adaptive search measures. In patients, psychophysical outcomes (as well as those from standard paper-and-pencil search tasks) reveal visual hemispatial neglect. Consistent with previous empirical studies of hemispatial neglect, lateralized impairments in adaptive conjunction search are greater than in adaptive feature search tasks. Furthermore, those with right hemisphere damage show greater lateralized deficits in conjunction search than do those with left hemisphere damage. We argue that adaptive tests, which automatically adjust to each individual's performance level, are efficient methods for both clinical evaluations and neuropsychological investigations and have the potential to detect subtle deficits even in chronic stages, when flagrant clinical signs have frequently resolved
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