162 research outputs found

    An exploratory study to determine procedures for implementation and evaluation of pupil assistance committees

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    Literature related to Pupil Assistance Committees indicates they were established to increase the capacity of regular education to serve pupils with learning and behavior problems without labeling them as handicapped. New Jersey mandates the establishment of Intervention and Referral Services which are a coordinated system in each building for the planning and delivery of intervention and referral services designed to assist students who are experiencing learning, behavior and health difficulties and to assist staff who have difficulties in addressing students\u27 learning, behavior or health needs. (N.J.A.C. 6A: 16-7.1) The purpose of this study was to identify an effective model of a Pupil Assistance Committee/Intervention and Referral Service, and to determine what types of interventions are most successful and what are the most important benefits of an effective Pupil Assistance Committee (PAC). A specific district, with two Kindergarten through Fourth Grade PAC\u27s in effect was examined to determine types of referrals made to the PAC, as well as the interventions recommended. Subsequent Referrals to Child Study Team were also tracked to determine effectiveness and appropriateness of the interventions. The teachers\u27 perceptions of their building\u27s PAC services were surveyed and a list of recommendations created based on the information gathered. The results of the survey noted inconsistency between the two schools of teachers\u27 perceptions of the usefulness and effectiveness of PAC\u27s. Teachers\u27 perceptions were found to be positive if referral to the Child Study Team was expedited. There was also inconsistency between the two schools as to the team\u27s practices related to parental contact and types of interventions implemented. Tutoring was found to be the most often recommended and easily documented intervention, as well as the intervention that achieved the most positive results. Based on the literature review and the results of this study, a coordinated PAC reform is warranted for the district involved in this study

    The SUPERTIGER Instrument: Measurement of Elemental Abundances of Ultra-Heavy Galactic Cosmic Rays

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    The SuperTIGER (Super Trans-Iron Galactic Element Recorder) instrument was developed to measure the abundances of galactic cosmic-ray elements from _(10)Ne to _(40)Zr with individual element resolution and the high statistics needed to test models of cosmic-ray origins. SuperTIGER also makes exploratory measurements of the abundances of elements with 40 29 and ∼60 with Z >49. Here, we describe the instrument, the methods of charge identification employed, the SuperTIGER balloon flight, and the instrument performance

    An electrostatic interaction between TEA and an introduced pore aromatic drives spring-in-the-door inactivation in Shaker potassium channels

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    Slow inactivation of Kv1 channels involves conformational changes near the selectivity filter. We examine such changes in Shaker channels lacking fast inactivation by considering the consequences of mutating two residues, T449 just external to the selectivity filter and V438 in the pore helix near the bottom of the selectivity filter. Single mutant T449F channels with the native V438 inactivate very slowly, and the canonical foot-in-the-door effect of extracellular tetraethylammonium (TEA) is not only absent, but the time course of slow inactivation is accelerated by TEA. The V438A mutation dramatically speeds inactivation in T449F channels, and TEA slows inactivation exactly as predicted by the foot-in-the-door model. We propose that TEA has this effect on V438A/T449F channels because the V438A mutation produces allosteric consequences within the selectivity filter and may reorient the aromatic ring at position 449. We investigated the possibility that the blocker promotes the collapse of the outer vestibule (spring-in-the-door) in single mutant T449F channels by an electrostatic attraction between a cationic TEA and the quadrupole moments of the four aromatic rings. To test this idea, we used in vivo nonsense suppression to serially fluorinate the introduced aromatic ring at the 449 position, a manipulation that withdraws electrons from the aromatic face with little effect on the shape, net charge, or hydrophobicity of the aromatic ring. Progressive fluorination causes monotonically enhanced rates of inactivation. In further agreement with our working hypothesis, increasing fluorination of the aromatic gradually transforms the TEA effect from spring-in-the-door to foot-in-the-door. We further substantiate our electrostatic hypothesis by quantum mechanical calculations

    Quantum Size Effects on the Chemical Sensing Performance of Two-Dimensional Semiconductors

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    We investigate the role of quantum confinement on the performance of gas sensors based on two-dimensional InAs membranes. Pd-decorated InAs membranes configured as H2 sensors are shown to exhibit strong thickness dependence, with ~100x enhancement in the sensor response as the thickness is reduced from 48 to 8 nm. Through detailed experiments and modeling, the thickness scaling trend is attributed to the quantization of electrons which favorably alters both the position and the transport properties of charge carriers; thus making them more susceptible to surface phenomena

    Dynamic Coupling of Voltage Sensor and Gate Involved in Closed-State Inactivation of Kv4.2 Channels

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    Voltage-gated potassium channels related to the Shal gene of Drosophila (Kv4 channels) mediate a subthreshold-activating current (ISA) that controls dendritic excitation and the backpropagation of action potentials in neurons. Kv4 channels also exhibit a prominent low voltage–induced closed-state inactivation, but the underlying molecular mechanism is poorly understood. Here, we examined a structural model in which dynamic coupling between the voltage sensors and the cytoplasmic gate underlies inactivation in Kv4.2 channels. We performed an alanine-scanning mutagenesis in the S4-S5 linker, the initial part of S5, and the distal part of S6 and functionally characterized the mutants under two-electrode voltage clamp in Xenopus oocytes. In a large fraction of the mutants (>80%) normal channel function was preserved, but the mutations influenced the likelihood of the channel to enter the closed-inactivated state. Depending on the site of mutation, low-voltage inactivation kinetics were slowed or accelerated, and the voltage dependence of steady-state inactivation was shifted positive or negative. Still, in some mutants these inactivation parameters remained unaffected. Double mutant cycle analysis based on kinetic and steady-state parameters of low-voltage inactivation revealed that residues known to be critical for voltage-dependent gate opening, including Glu 323 and Val 404, are also critical for Kv4.2 closed-state inactivation. Selective redox modulation of corresponding double-cysteine mutants supported the idea that these residues are involved in a dynamic coupling, which mediates both transient activation and closed-state inactivation in Kv4.2 channels

    Bile Acid Inhibition of N-type Calcium Channel Currents from Sympathetic Ganglion Neurons

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    Under some pathological conditions as bile flow obstruction or liver diseases with the enterohepatic circulation being disrupted, regurgitation of bile acids into the systemic circulation occurs and the plasma level of bile acids increases. Bile acids in circulation may affect the nervous system. We examined this possibility by studying the effects of bile acids on gating of neuronal (N)-type Ca2+ channel that is essential for neurotransmitter release at synapses of the peripheral and central nervous system. N-type Ca2+ channel currents were recorded from bullfrog sympathetic neuron under a cell-attached mode using 100 mM Ba2+ as a charge carrier. Cholic acid (CA, 10-6 M) that is relatively hydrophilic thus less cytotoxic was included in the pipette solution. CA suppressed the open probability of N-type Ca2+ channel, which appeared to be due to an increase in null (no activity) sweeps. For example, the proportion of null sweep in the presence of CA was ~40% at +40 mV as compared with ~8% in the control recorded without CA. Other single channel properties including slope conductance, single channel current amplitude, open and shut times were not significantly affected by CA being present. The results suggest that CA could modulate N-type Ca2+ channel gating at a concentration as low as 10-6 M. Bile acids have been shown to activate nonselective cation conductance and depolarize the cell membrane. Under pathological conditions with increased circulating bile acids, CA suppression of N-type Ca2+ channel function may be beneficial against overexcitation of the synapses
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