Learner-centered social support: enhancing online distance education for underserved rural high school students in the United States

Over the past decade, federal programs in the United States have largely addressed the well-documented problem of differences in basic access to technology between rural schools and their suburban and urban counterparts. Consequently, rural schools are better able to prepare their students for post-secondary education and the workplace where digital literacy is essential. As technology access improves, online distance education (ODE) is seen as a solution to significant challenges faced by rural schools, including a lack of highly-qualified teachers and declining population. However, ODE has high attrition rates, partly because participants’ social needs are often neglected. Additionally, students' success depends on their abilities to engage in self-regulated learning, effective time management and self-reflection, skills that many high school students are still developing. This paper describes an experimental research study funded by the U.S. Department of Education, currently underway in rural high schools across the U.S. The research adds to a growing body of work that attempts to expand understanding of the digital divide. Increasingly, schools realise that this is no longer an issue of mere access to equipment; education technology projects should incorporate strategies that ensure the success of previously marginalised communities. Our intervention, based on the APA’s Learner- Centered Principles, involves training on-site facilitators to provide social support for students involved in ODE. Preliminary findings indicate that the intervention group has a significantly lower dropout rate

Rapid synaptic vesicle endocytosis in cone photoreceptors of salamander retina.

Following synaptic vesicle exocytosis, neurons retrieve the fused membrane by a process of endocytosis to provide a supply of vesicles for subsequent release and maintain the presynaptic active zone. Rod and cone photoreceptors use a specialized structure called the synaptic ribbon that enables them to sustain high rates of neurotransmitter release. They must also employ mechanisms of synaptic vesicle endocytosis capable of keeping up with release. While much is known about endocytosis at another retinal ribbon synapse, that of the goldfish Mb1 bipolar cell, less is known about endocytosis in photoreceptors. We used capacitance recording techniques to measure vesicle membrane fusion and retrieval in photoreceptors from salamander retinal slices. We found that application of brief depolarizing steps (\u3c100 \u3ems) to cones evoked exocytosis followed by rapid endocytosis with a time constant ∼250 ms. In some cases, the capacitance trace overshot the baseline, indicating excess endocytosis. Calcium had no effect on the time constant, but enhanced excess endocytosis resulting in a faster rate of membrane retrieval. Surprisingly, endocytosis was unaffected by blockers of dynamin, suggesting that cone endocytosis is dynamin independent. This contrasts with synaptic vesicle endocytosis in rods, which was inhibited by the dynamin inhibitor dynasore and GTPγS introduced through the patch pipette, suggesting that the two photoreceptor types employ distinct pathways for vesicle retrieval. The fast kinetics of synaptic vesicle endocytosis in photoreceptors likely enables these cells to maintain a high rate of transmitter release, allowing them to faithfully signal changes in illumination to second-order neurons

Declaration of the Modern Caliphate: Understanding the Importance of Mosul to ISIL

This paper examines the importance of the Iraqi city of Mosul to ISIL. Special attention is given to the conquering of Mosul, ISIL\u27s governance, and the Battle of Mosul

Improving the Nutrient Content of Food through Genetic Modification: Evidence from Experimental Auctions on Consumer Acceptance

This paper assesses consumers’ acceptance of nutritionally enhanced vegetables using a series of auction experiments administered to a random sample of adult consumers. Evidence suggests that consumers are willing to pay significantly more for fresh produce with labels signaling enhanced levels of antioxidants and vitamin C achieved by moving genes from within the species, as opposed to across species. However, this premium is significantly affected by diverse information treatments injected into the experiments

Spectral Absorption Coefficient of Additive Manufacturing Polymers

As NASA turns to additive manufacturing processes, there is a need to ensure that the parts they produce are reliable. This is especially true when creating parts in space, where resources are limited and failure could result in catastrophe. Active thermography has shown potential as a non-destructive quality assurance technique for additive manufacturing processes. Heat transfer models used in active thermography techniques require accurate material property measurements in order to extract useful information about the system, including defect location. The spectral absorption coefficient, which determines the depth at which radiative power is absorbed into a surface, is a material property necessary for performing active thermography on AM polymers. This paper presents measurements of spectral absorption coefficients of polymers commonly used in additive manufacturing. Spectral absorption coefficients for fully dense PLA, ABS, and Nylon 12 samples are reported. Future work is needed to measure the spectral absorption coefficients of different materials and colored filaments commonly used in additive manufacturing

Ca2+ Diffusion through Endoplasmic Reticulum Supports Elevated Intraterminal Ca2+ Levels Needed to Sustain Synaptic Release from Rods in Darkness.

UNLABELLED: In addition to vesicle release at synaptic ribbons, rod photoreceptors are capable of substantial slow release at non-ribbon release sites triggered by Ca(2+)-induced Ca(2+) release (CICR) from intracellular stores. To maintain CICR as rods remain depolarized in darkness, we hypothesized that Ca(2+) released into the cytoplasm from terminal endoplasmic reticulum (ER) can be replenished continuously by ions diffusing within the ER from the soma. We measured [Ca(2+)] changes in cytoplasm and ER of rods from Ambystoma tigrinum retina using various dyes. ER [Ca(2+)] changes were measured by loading ER with fluo-5N and then washing dye from the cytoplasm with a dye-free patch pipette solution. Small dye molecules diffused within ER between soma and terminal showing a single continuous ER compartment. Depolarization of rods to -40 mV depleted Ca(2+) from terminal ER, followed by a decline in somatic ER [Ca(2+)]. Local activation of ryanodine receptors in terminals with a spatially confined puff of ryanodine caused a decline in terminal ER [Ca(2+)], followed by a secondary decrease in somatic ER. Localized photolytic uncaging of Ca(2+) from o-nitrophenyl-EGTA in somatic ER caused an abrupt Ca(2+) increase in somatic ER, followed by a slower Ca(2+) increase in terminal ER. These data suggest that, during maintained depolarization, a soma-to-terminal [Ca(2+)] gradient develops within the ER that promotes diffusion of Ca(2+) ions to resupply intraterminal ER Ca(2+) stores and thus sustain CICR-mediated synaptic release. The ability of Ca(2+) to move freely through the ER may also promote bidirectional communication of Ca(2+) changes between soma and terminal. SIGNIFICANCE STATEMENT: Vertebrate rod and cone photoreceptors both release vesicles at synaptic ribbons, but rods also exhibit substantial slow release at non-ribbon sites triggered by Ca(2+)-induced Ca(2+) release (CICR). Blocking CICR inhibits \u3e50% of release from rods in darkness. How do rods maintain sufficiently high [Ca(2+)] in terminal endoplasmic reticulum (ER) to support sustained CICR-driven synaptic transmission? We show that maintained depolarization creates a [Ca(2+)] gradient within the rod ER lumen that promotes soma-to-terminal diffusion of Ca(2+) to replenish intraterminal ER stores. This mechanism allows CICR-triggered synaptic release to be sustained indefinitely while rods remain depolarized in darkness. Free diffusion of Ca(2+) within the ER may also communicate synaptic Ca(2+) changes back to the soma to influence other critical cell processes

Aligning self-assembled perylene bisimides in a magnetic field

Photoconductive self-assembled 1D structures can be formed by perylene bisimides. These structures are generally randomly orientated, limiting their applications as conductive wires. Here, we show that magnetic fields can be used to create highly aligned, directionally-dependent thin films. This approach leads to well-aligned structures over large areas

Targeting liver myofibroblasts: a novel approach in anti-fibrogenic therapy

Chronic liver disease results in a liver-scarring response termed fibrosis. Excessive scarring leads to cirrhosis, which is associated with high morbidity and mortality. The only treatment for liver cirrhosis is liver transplantation; therefore, much attention has been directed toward therapies that will slow or reverse fibrosis. Although anti-fibrogenic therapies have been shown to be effective in experimental animal models, licensed therapies have yet to emerge. A potential problem for any anti-fibrogenic therapy in the liver is the existence of the body’s major drug metabolising cell (the hepatocyte) adjacent to the primary fibrosis-causing cell, the myofibroblast. This article reviews the development of a human recombinant single-chain antibody (scAb) that binds to the surface of myofibroblasts. This antibody binds specifically to myofibroblasts in fibrotic mouse livers. When conjugated with a compound that stimulates myofibroblast apoptosis, the antibody directs the specific apoptosis of myofibroblasts with greater specificity and efficacy than the free compound. The antibody also reduces the adverse effect of liver macrophage apoptosis and—in contrast to the free compound—reversed fibrosis in the sustained injury model used. These data suggest that specifically stimulating the apoptosis of liver myofibroblasts using a targeting antibody has potential in the treatment of liver fibrosis

Titrations without the Additions: The Efficient Determination of pKa Values Using NMR Imaging Techniques

It can be very informative to acquire NMR spectra of a sample as a function of the solution pH. Examples can be found in the design of host–guest complexes or in the determination of the pKa values of organic molecules. In the conventional procedure, a series of spectra must be recorded and the pH of the sample adjusted manually between successive NMR measurements. As an alternative to this laborious procedure, we demonstrate how controlled pH gradients may be established in 5 mm NMR tubes and analyzed using standard NMR equipment in a “single shot” experiment. Using 1H NMR imaging techniques and a set of NMR pH indicator compounds, we are able to measure the pH of a sample as a function of position along a pH gradient. We are thus able to obtain the necessary set of 1H NMR spectra as a function of pH from a single sample in a single NMR experiment. As proof of concept, we demonstrate how the technique may be employed for the determination of the pKa values of small organic molecules. We are able to measure pKa values from 1 to 11 to within 0.1 units of their literature values. The method is robust to variations in the setting of the pH gradients and can be readily implemented through an automated sample changer