Critical mass flux through short Borda type inlets of various cross sections

Mass flux measurements associated with chocked flows through four Borda type inlet geometries: circular, square, triangular and rectangular (two-dimensional) and two sharp edged geometries taken over a very wide range of inlet stagnation conditions. The measurements indicate that: (1) the mass flux is independent of the inlet cross-section geometry and (2) the mass flux is dependent only on the inlet stagnation conditions. Also by using choked flow results found in the literature, the reduced mass flux is independent of working fluid. Two implications are drawn which remain to be verified: (1) since seal leak rates are weakly dependent on geometry but pressure distribution is strongly dependent on geometry, seal design efforts should be directed more toward controlling the dynamics, and (2) high-L/D ducts of arbitrary cross section and Borda type inlets can possess free jets

Perspectives of Middle School Band Members on High School Band

Student retention is essential for band programs at any level to succeed and grow. This study includes results of student surveys of current high-school students who took band during their middle school years, seeking essential factors affecting student perceptions about continuation into high school band programs. Research into band student enrollment and retention exist, yet limited resources focus on transitioning from middle to high school. Studies indicate that participation in large music ensembles, such as bands, provides social, emotional, and academic benefits. Increasing student retention across this transition could yield improved student experiences and achievement in music and beyond. Existing research combined with student survey results constitutes a qualitative thematic analyzing why students who have learned much about the basics of instrumental music in middle school band elect not to continue their studies in high school. Based on existing literature, peer-connectedness, parental support, and director rapport are likely indicators for continuation in the band. By improving band student retention rates, improvements in overall graduation rates may also be achieved

The role of professional advising in the liberal arts

The purpose of this study was to investigate the role of professional academic advising in the liberal arts. This study focused on the impact of professional academic advising in the liberal arts. This study also focused on the extent to which professional administrators are involved in supporting the professional academic advisors. This was a Total Population Study since all five College of Humanities and Social Sciences embedded advisors participated in this study and the four administrators participated in this study. Qualitative research, through the use of 30 minute individual interviews, was used to collect data. Interview questions focused on demographic information, advising role, advising skills and education, post-graduation options, degree value, and any suggested changes. The research questions presented in Chapter I of this study were used to inform and develop the interview questions. Qualitative content analysis techniques, per Sisco (1981), were used in order to classify and categorize themes. Themes were presented through tables and illustrative quotes. The major finding of this study is just how critical experiential learning is to the success of Liberal Arts students. Additionally, professional academic advisors are critical in linking Liberal Arts students to these opportunities

Prolonging thermal barrier coated specimen life by thermal cycle management

Measurements were made of the rate of increase in temperature of a ZrO2-8Y2O3 thermal barrier coated (TBC) specimen for various values of fuel/air (F/A) ratios when the specimen is exposed to a 0.3 Mach burner flame. For rod specimens in a carousel, the heating rates increased with (F/A) ratio and were higher at the inward facing surface for a given (F/A). Plate specimens were more sensitive to burner variations. Calculated results are given for the radial stress in the coated rod specimens for variations in (F/A) ratios from 0.04 to 0.065. Over this range, the radial stress varies from 4.3 to 5.3 MPa. The results indicate that controlling the heating rate of a TBC by controlling the (F/A) ratio offers a potential method to prolong TBC cyclic life; uncontrolled (F/A) ratios will produce scatter in experimental results. Geometric arrangement can have an equivalent effect, but is usually fixed by design

Secondary School Band: Student Retention and Director Issues-Challenges and Strategies

Student involvement in school band programs can be a positive learning experience. By featuring both physical activity and multi-level brain function, successful band programs support positive student results in both academic and social development. Graduation rates in band students are often higher than that of the overall student population. By recognizing this, increased graduation rates could be supported by increasing and retaining band student enrollment. This study examined and identifies the characteristics of band programs that contribute to increased effectiveness through the utilization of one director for both middle and high school. Additionally, the musical qualities band students having the same director for both middle and high school was examined. Social and peer issues impact the lives of most adolescents. The significant emotional support experienced by many band students during the development of multi-year personal relationships serves to enhance their development and success in areas outside of music. By examining existing research in this context, the study found that there is an increased enrollment in situations where band directors are utilized in both the middle and high school band situation. The literature suggests that the continuity of instruction illustrates a musical rapport and understanding between student and director unique to the band experience

Calcium-activated potassium conductances contribute to action potential repolarization at the soma but not the dendrites of hippocampal CA1 pyramidal neurons

Evidence is accumulating that voltage-gated channels are distributed nonuniformly throughout neurons and that this nonuniformity underlies regional differences in excitability within the single neuron. Previous reports have shown that Ca 2ϩ , Na ϩ , A-type K ϩ , and hyperpolarization-activated, mixed cation conductances have varying distributions in hippocampal CA1 pyramidal neurons, with significantly different densities in the apical dendrites compared with the soma. Another important channel mediates the large-conductance Ca 2ϩ -activated K ϩ current (I C ), which is responsible in part for repolarization of the action potential (AP) and generation of the afterhyperpolarization that follows the AP recorded at the soma. We have investigated whether this current is activated by APs retrogradely propagating in the dendrites of hippocampal pyramidal neurons using whole-cell dendritic patch-clamp recording techniques. We found no I C activation by back-propagating APs in distal dendritic recordings. Dendritic APs activated I C only in the proximal dendrites, and this activation decayed within the first 100-150 m of distance from the soma. The decay of I C in the proximal dendrites occurred despite AP amplitude, plus presumably AP-induced Ca 2ϩ influx, that was comparable with that at the soma. Thus we conclude that I C activation by action potentials is nonuniform in the hippocampal pyramidal neuron, which may represent a further example of regional differences in neuronal excitability that are determined by the nonuniform distribution of voltage-gated channels in dendrites

Input source and strength influences overall firing phase of model hippocampal CA1 pyramidal cells during theta: Relevance to REM sleep reactivation and memory consolidation

In simulation studies using a realistic model CA1 pyramidal cell, we accounted for the shift in mean firing phase from theta cycle peaks to theta cycle troughs during rapid-eye movement (REM) sleep reactivation of hippocampal CA1 place cells over several days of growing familiarization with an environment (Brain Res 855:176–180). Changes in the theta drive phase and amplitude between proximal and distal dendritic regions of the cell modulated the theta phase of firing when stimuli were presented at proximal and distal dendritic locations. Stimuli at proximal dendritic sites (proximal to 100 Μm from the soma) invoked firing with a significant phase preference at the depolarizing theta peaks, while distal stimuli (>290 Μm from the soma) invoked firing at hyperpolarizing theta troughs. The input location-related phase preference depended on active dendritic conductances, a sufficient electrotonic separation between input sites and theta-induced subthreshold membrane potential oscillations in the cell. The simulation results predict that the shift in mean theta phase during REM sleep cellular reactivation could occur through potentiation of distal dendritic (temporo-ammonic) synapses and depotentiation of proximal dendritic (Schaffer collateral) synapses over the course of familiarization. © 2006 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49532/1/20143_ftp.pd

Know Your Current Ih: Interaction with a Shunting Current Explains the Puzzling Effects of Its Pharmacological or Pathological Modulations

The non-specific, hyperpolarization activated, Ih current is particularly involved in epilepsy and it exhibits an excitatory or inhibitory action on synaptic integration in an apparently inconsistent way. It has been suggested that most of the inconsistencies could be reconciled invoking an indirect interaction with the M-type K+ current, another current involved in epilepsy. However, here we show that the original experiments, and the simplified model used to explain and support them, cannot explain in a conclusive way the puzzling Ih actions observed in different experimental preparations. Using a realistic model, we show instead how and why a shunting current, such as that carried by TASK-like channels, and dependent on Ih channel is able to explain virtually all experimental findings on Ih up- or down-regulation by modulators or pathological conditions. The model results suggest several experimentally testable predictions to characterize in more details this elusive and peculiar interaction, which may be of fundamental importance in the development of new treatments for all those pathological and cognitive dysfunctions caused, mediated, or affected by Ih