1,450 research outputs found
Conceptualizing socioscientific decision making from a review of research in science education
Abstract: This article proposes a theoretical framework for conceptualizing socioscientific decision making, reviews current research in this area, and intends to shed some light on the instructional design for the classroom implementation of socioscientific decision making. The framework involves 3 phases: formulate the decision-making space, posit a decision-making strategy, and reflect on the decision-making process. A total of 24 articles that specifically focused on socioscientific decision making were included. They were classified into 2 groups. The first group explored studentsâ socioscientific decision-making behavior and its relationships with their cognitive conditions. The second examined the effectiveness of the interventions, that is, task conditions. The analysis showed that most of the studies in both groups focused on phase 1 and studied 3 research themes: informal reasoning, evidence-based reasoning, and social interactions. The findings indicated the challenges phases 1 and 2 posed to students, such as prioritizing criteria and employing a suitable decision-making strategy. Two cognitive conditions, scientific knowledge and scientific epistemological beliefs, appeared to have a more direct impact on evidence-based reasoning rather than on informal reasoning. Group 2 studies designed various interventions and looked into divergent socioscientific decision-making performances across 3 phases. The framework helps conceptualize socioscientific decision making in a more structural and holistic way. The content review provides instructional insights for the socioscientific decision-making process and suggests several future research directions
Reducing Asymptotic Bias of Weak Instrumental
In this paper, we consider the instrumental variables estimation (the two-stage least squares estimator and the limited information maximum likelihood estimator) using weak instruments in a repeated measurements or a panel data model. We show that independently repeated cross-sectional data can reduce the asymptotic bias of the instrumental variables estimation when instruments are weakly correlated with endogenous variables. When the number of repeated measurements tends to infinity, we can achieve consistent instrumental variables estimation with weak instruments.This paper is forthcoming in Statistics & Probability Letters
Diverse anisotropy of phonon transport in two-dimensional IV-VI compounds: A comparative study
New classes two-dimensional (2D) materials beyond graphene, including layered
and non-layered, and their heterostructures, are currently attracting
increasing interest due to their promising applications in nanoelectronics,
optoelectronics and clean energy, where thermal transport property is one of
the fundamental physical parameters. In this paper, we systematically
investigated the phonon transport properties of 2D orthorhombic group IV-VI
compounds of , , and by solving the Boltzmann transport
equation (BTE) based on first-principles calculations. Despite the similar
puckered (hinge-like) structure along the armchair direction as phosphorene,
the four monolayer compounds possess diverse anisotropic properties in many
aspects, such as phonon group velocity, Young's modulus and lattice thermal
conductivity (), etc. Especially, the along the zigzag and
armchair directions of monolayer shows the strongest anisotropy while
monolayer and shows an almost isotropy in phonon transport. The
origin of the diverse anisotropy is fully studied and the underlying mechanism
is discussed in detail. With limited size, the could be effectively
lowered, and the anisotropy could be effectively modulated by nanostructuring,
which would extend the applications in nanoscale thermoelectrics and thermal
management. Our study offers fundamental understanding of the anisotropic
phonon transport properties of 2D materials, and would be of significance for
further study, modulation and aplications in emerging technologies.Comment: 14 pages, 8 figures, 2 table
DNMT3a in the hippocampal CA1 is crucial in the acquisition of morphine selfâadministration in rats
Drugâreinforced excessive operant responding is one fundamental feature of long-lasting addictionâlike behaviors and relapse in animals. However, the transcriptional regulatory mechanisms responsible for the persistent drugâspecific (not natural rewards) operant behavior are not entirely clear. In this study, we demonstrate a key role for one of the de novo DNA methyltransferase, DNMT3a, in the acquisition of morphine selfâadministration (SA) in rats. The expression of DNMT3a in the hippocampal CA1 region but not in the nucleus accumbens shell was significantly upâregulated after 1â and 7âday morphine SA (0.3 mg/kg/infusion) but not after the yoked morphine injection. On the other hand, saccharin SA did not affect the expression of DNMT3a or DNMT3b. DNMT inhibitor 5âazaâ2âdeoxycytidine (5âaza) microinjected into the hippocampal CA1 significantly attenuated the acquisition of morphine SA. Knockdown of DNMT3a also impaired the ability to acquire the morphine SA. Overall, these findings suggest that DNMT3a in the hippocampus plays an important role in the acquisition of morphine SA and may be a valid target to prevent the development of morphine addiction.
Includes Supplemental informatio
A Bayesian measurement error model for two-channel cell-based RNAi data with replicates
RNA interference (RNAi) is an endogenous cellular process in which small
double-stranded RNAs lead to the destruction of mRNAs with complementary
nucleoside sequence. With the production of RNAi libraries, large-scale RNAi
screening in human cells can be conducted to identify unknown genes involved in
a biological pathway. One challenge researchers face is how to deal with the
multiple testing issue and the related false positive rate (FDR) and false
negative rate (FNR). This paper proposes a Bayesian hierarchical measurement
error model for the analysis of data from a two-channel RNAi high-throughput
experiment with replicates, in which both the activity of a particular
biological pathway and cell viability are monitored and the goal is to identify
short hair-pin RNAs (shRNAs) that affect the pathway activity without affecting
cell activity. Simulation studies demonstrate the flexibility and robustness of
the Bayesian method and the benefits of having replicates in the experiment.
This method is illustrated through analyzing the data from a RNAi
high-throughput screening that searches for cellular factors affecting HCV
replication without affecting cell viability; comparisons of the results from
this HCV study and some of those reported in the literature are included.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS496 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Minute-Level Speed Identification and Assessment of Bacteria/Cells Using Electrokinetic Assistance
Conventional techniques for detection and analysis of cells/bacteria use Western blot and ELISA kits that are high cost and long time consuming. An ideal advanced biosensor (molecular or whole cells detections) unit must have several important features: rapid detection time (<15 minutes), high sensitivity (102 cells/ml for whole cell detection or sub-nM concentration for molecular detection), high specificity, small, and inexpensive instrumentation/configuration. Two novel platforms will be introduced here, including an optofluidic system for the rapid on-chip detection of bacterial infection and a cell-based biochip for the label-free assessment of drug susceptibility on cancer cells. Rapid identification of rare pathogen from a very dense human blood sample is realized through combining the hybrid electrokinetic concentration with on-chip surface-enhanced Raman spectroscopy (SERS) identification of bacteria based on their detected SERS spectra. Compared to the current method in the hospital, this simple and rapid platform accelerated the detection time from 2 days to a few minutes. The cell-based biochip uses a novel, rapid, and label-free approach- AC electric field induced electro-rotation (eROT) to evaluate the drug susceptibility of cancer cells. The isolated lung cancer cells were successfully analyzed using eROT approach for the rapid and label-free assessment of the drug susceptibility of cancer cells. eROT spectra for different drug-treated cancer cells was successfully determined to the drug resistance and susceptibilities through their frequency-dependent rotation speeds. The relationship and trend between eROT method and conventional method are very agreement
Observation on the curative effects of two surgical methods for basic intermittent exotropia
AIM:To explore the differences between unilateral recess-resection(R & R)and bilateral lateral rectus recession(BLR-rec)in the treatment of basic intermittent exotropia.METHODS: A retrospective analysis of treatment of basic intermittent exotropia in 89 patients, in which 49 cases underwent unilateral recess-resection, 40 cases underwent bilateral lateral rectus recession of external rectus retroperitoneal surgery January 2013 to January 2015 in our hospital. The stereopsis and strabismus were observed in 1d, 1, 6mo, 1 and 2a after operation.RESULTS: There was no significant difference in the success rate and oblique degree between the two groups after 1d, 1, 6mo, 1 and 2a(all P>0.05), but the success rate of the operation was reducing as time passed. After 2d of the operation, the drift of the R & R group was 12.10±5.74PD and the drift of the BLR-rec group was 7.78±4.21PD, the difference was statistically significant(P=0.021). The R & R group was more likely to cause lateral slanting than BLR-rec group. Two groups of patients with nearly stereopsis were both significantly improved, there was no significant difference between the two groups in the two groups(Ï2=4.530, P=0.210). CONCLUSION: The long-term stability of BLR-rec is superior to R & R
Relationship between Angiotensin-Converting Enzyme Insertion/Deletion Gene Polymorphism and Susceptibility of Minimal Change Nephrotic Syndrome: A Meta-Analysis
Aim. This meta-analysis was performed to evaluate the association between ACE I/D gene polymorphism and MCNS susceptibility.
Method. A predefined literature search and selection of eligible relevant studies were performed to collect the data from electronic databases.
Results. Six articles were identified for the analysis of association between ACE I/D gene polymorphism and MCNS risk, including 4 for Asians, one in Caucasian population and one for Africans. There was a markedly positive association between D allele or DD genotype and MCNS susceptibility in Asians (D: P = .01, DD: P = .02), but not for Caucasians and Africans (Caucasians: D: P = .16, DD: P = .98;
Africans: D: P = .81, DD: P = .49). Furthermore, the II genotype seemed not to play a protective role against MCNS risk for Asians, Caucasians and Africans (P = .12, P = .09, P = .76, resp.). Interestingly, there was also significant association between ACE I/D gene polymorphism and MCNS susceptibility in overall populations (D: P = .007, DD: P = .04, II: P = .03).
Conclusion. D allele or DD genotype might be a significant genetic molecular marker for MCNS susceptibility in Asians and overall populations, but not for Caucasians and Africans. More larger and rigorous genetic epidemiological investigations are required to further explore this association
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