32,691 research outputs found
Cognitive Styles and Adaptive Web-based Learning
Adaptive hypermedia techniques have been widely used in web-based learning programs. Traditionally these programs have focused on adapting to the user’s prior knowledge, but recent research has begun to consider adapting to cognitive style. This study aims to determine whether offering adapted interfaces tailored to the user’s cognitive style would improve their learning performance and perceptions. The findings indicate that adapting interfaces based on cognitive styles cannot facilitate learning, but mismatching interfaces may cause problems for learners. The results also suggest that creating an interface that caters for different cognitive styles and gives a selection of navigational tools might be more beneficial for learners. The implications of these findings for the design of web-based learning programs are discussed
Learning Motion Predictors for Smart Wheelchair using Autoregressive Sparse Gaussian Process
Constructing a smart wheelchair on a commercially available powered
wheelchair (PWC) platform avoids a host of seating, mechanical design and
reliability issues but requires methods of predicting and controlling the
motion of a device never intended for robotics. Analog joystick inputs are
subject to black-box transformations which may produce intuitive and adaptable
motion control for human operators, but complicate robotic control approaches;
furthermore, installation of standard axle mounted odometers on a commercial
PWC is difficult. In this work, we present an integrated hardware and software
system for predicting the motion of a commercial PWC platform that does not
require any physical or electronic modification of the chair beyond plugging
into an industry standard auxiliary input port. This system uses an RGB-D
camera and an Arduino interface board to capture motion data, including visual
odometry and joystick signals, via ROS communication. Future motion is
predicted using an autoregressive sparse Gaussian process model. We evaluate
the proposed system on real-world short-term path prediction experiments.
Experimental results demonstrate the system's efficacy when compared to a
baseline neural network model.Comment: The paper has been accepted to the International Conference on
Robotics and Automation (ICRA2018
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Mifepristone Antagonization With Progesterone to Prevent Medical Abortion: A Randomized Controlled Trial.
ObjectiveTo estimate the efficacy and safety of mifepristone antagonization with high-dose oral progesterone.MethodsWe planned to enroll 40 patients in a double-blind, placebo-controlled, randomized trial. We enrolled patients at 44-63 days of gestation with ultrasound-confirmed gestational cardiac activity who were planning surgical abortion. Participants ingested mifepristone 200 mg and initiated oral progesterone 400 mg or placebo 24 hours later twice daily for 3 days, then once daily until their planned surgical abortion 14-16 days after enrollment. Follow-up visits were scheduled 3±1, 7±1, and 15±1 days after mifepristone intake with ultrasonography and blood testing for human chorionic gonadotropin and progesterone. Participants exited from the study when they had their surgical abortion or earlier for gestational cardiac activity absence, gestational sac expulsion, or medically indicated suction aspiration. We assessed the primary outcome of continued gestational cardiac activity at approximately 2 weeks (15±1 day), side effects after drug ingestion, and safety outcomes including hemorrhage and emergent treatment.ResultsWe enrolled participants from February to July 2019 and stopped enrollment after 12 patients for safety concerns. Mean gestational age was 52.5 days. Two (one per group) voluntarily discontinued 3 days after mifepristone ingestion for subjective symptoms (nausea and vomiting, bleeding). Among the remaining 10 patients (five per group), gestational cardiac activity continued for 2 weeks in four in the progesterone group and two in the placebo group. One patient in the placebo group had no gestational cardiac activity 3 days after mifepristone use. Severe hemorrhage requiring ambulance transport to hospital occurred in three patients; one received progesterone (complete expulsion, no aspiration) and two received placebo (aspiration for both, one required transfusion). We halted enrollment after the third hemorrhage. No other significant side effects were reported.ConclusionWe could not estimate the efficacy of progesterone for mifepristone antagonization due to safety concerns when mifepristone is administered without subsequent prostaglandin analogue treatment. Patients in early pregnancy who use only mifepristone may be at high risk of significant hemorrhage.Clinical trial registrationClinicalTrials.gov, NCT03774745
Improving the Trust of Users on Social Networking Sites via Self-Construal Traits
The ability to remove trust concerns for online users is crucial for sustainable online development, especially relating to social networking sites. This study examines independent self-construal and interdependent self-construal as pertinent factors to increase trust on social networking sites. The classification of trust broken down into calculation-, familiarity-, structural assurance-, and situational normality-based trust was adopted in this study. Data was collected from 398 members of the leading social network site: Facebook. Regression analysis was adopted to test the data against the casual relationship among the four trust constructs. Data analysis indicates that the constructs of interdependent self-construal and independent selfconstrual individually, and together, can account for the increase of trust on a social networking site; however interdependent self-construal has the largest explanatory power. These results suggest that social networking sites continuously increase the degree of interdependence of users and develop new applications to engage users to stay longer for each visit. As a result of these measures, social networking sites can sustain the trust of users
Function of the Signal Peptide and N- and C-terminal Propeptides in the Leucine Aminopeptidase from \u3cem\u3eAeromonas proteolytica\u3c/em\u3e
The leucine aminopeptidase from Aeromonas proteolytica (also known as Vibrio proteolyticus) (AAP) is a metalloenzyme with broad substrate specificity. The open reading frame (ORF) for AAP encodes a 54 kDa enzyme, however, the extracellular enzyme has a molecular weight of 43 kDa. This form of AAP is further processed to a mature, thermostable 32 kDa form but the exact nature of this process is unknown. Over-expression of different forms of AAP in Escherichia coli (with AAP\u27s native leader sequence, with and without the N- and/or C-terminal propeptides, and as fusion protein) has allowed a model for the processing of wild-type AAP to be proposed. The role of the A. proteolytica signal peptide in protein secretion as well as comparison to other known signal peptides reveals a close resemblance of the A. proteolytica signal peptide to the outer membrane protein (OmpA) signal peptide. Over-expression of the full 54 kDa AAP enzyme provides an enzyme that is significantly less active, due to a cooperative inhibitory interaction between both propeptides. Over-expression of AAP lacking its C-terminal propeptide provided an enzyme with an identical kcat value to wild-type AAP but exhibited a larger Km value, suggesting competitive inhibition of AAP by the N-terminal propeptide (Ki∼0.13 nM). The recombinant 32 kDa form of AAP was characterized by kinetic and spectroscopic methods and was shown to be identical to mature, wild-type AAP. Therefore, the ease of purification and processing of rAAP along with the fact that large quantities can be obtained now allow new detailed mechanistic studies to be performed on AAP through site-directed mutagenesis
Living on the edge of chaos: minimally nonlinear models of genetic regulatory dynamics
Linearized catalytic reaction equations modeling e.g. the dynamics of genetic
regulatory networks under the constraint that expression levels, i.e. molecular
concentrations of nucleic material are positive, exhibit nontrivial dynamical
properties, which depend on the average connectivity of the reaction network.
In these systems the inflation of the edge of chaos and multi-stability have
been demonstrated to exist. The positivity constraint introduces a nonlinearity
which makes chaotic dynamics possible. Despite the simplicity of such minimally
nonlinear systems, their basic properties allow to understand fundamental
dynamical properties of complex biological reaction networks. We analyze the
Lyapunov spectrum, determine the probability to find stationary oscillating
solutions, demonstrate the effect of the nonlinearity on the effective in- and
out-degree of the active interaction network and study how the frequency
distributions of oscillatory modes of such system depend on the average
connectivity.Comment: 11 pages, 5 figure
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Gabapentin for pain management after osmotic dilator insertion and prior to dilation and evacuation: A randomized controlled trial.
ObjectiveTo evaluate if gabapentin 600 mg reduces pain after osmotic dilator placement the day before a dilation and evacuation (D&E) procedure.Study designWe conducted a double-blind, placebo-controlled, randomized (stratified by vaginal parity) trial among women undergoing osmotic dilator placement before D&E at 15-23 5/7 weeks gestation. Subjects received gabapentin 600 mg or placebo 30 min before dilator placement, with re-dosing 8 h later. We assessed pain after dilator placement using a numeric rating scale (NRS; scale 0-10) at 5 min, 2, 4, and 8 h, and at presentation for D&E. The primary outcome was median NRS pain score change from baseline to 8 h after dilator placement. Secondary outcomes included gabapentin-related side effects and analgesic use.ResultsOf 121 randomized women, we excluded three subjects (allergic reaction [placebo], randomization error, no NRS data), leaving 60 gabapentin and 58 placebo subjects. Of 110 (93%) women who provided 8-hour data, median pain score changes from baseline did not differ between gabapentin and placebo groups overall (2 vs. 2.5, p = 0.52), in vaginally nulliparous women (2 vs. 4, p = 0.10) or in parous women (2 vs. 1.5, p = 0.37). We found no statistically significant differences in median pain score change from baseline to any timepoint overall or when stratified by parity. Beginning at 2 h after dilator placement, more gabapentin than placebo users experienced dizziness (29/53[55%] vs. 11/53[21%], p = 0.001) and tiredness (34/54[63%] vs. 17/54[31%], p = 0.002). The proportion of women using narcotics did not differ between gabapentin (35/60[58%]) or placebo (40/58[69%]) users (p = 0.26).ConclusionsGabapentin does not reduce pain with overnight osmotic dilator placement prior to D&E and causes drug-related side effects.Implications statementWomen experience pain, mostly mild to moderate, with overnight cervical dilator placement at 15-23 5/7 weeks gestation. About 2/3 of women will use a limited quantity of narcotics if provided. Gabapentin does not decrease the pain with or following dilator placement and does not decrease narcotic use
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