3,846 research outputs found

    The Relationship Between Principals\u27 Leadership Self-Efficacy, Student Achievement and School Performance

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    The two major components of school accountability, under the Mississippi Schools Accountability System, are growth expectation and school achievement. Mississippi schools are assigned a school performance classification based upon student achievement and whether schools did not meet, met, or exceeded their growth expectation. The primary purpose of this study was to determine if there is a statistically significant relationship between principals\u27 ratings of self-efficacy, school performance, and school growth status. In addition, this study sought to determine if there is a statistically significant relationship between principals\u27 ratings of delegatee performance, school performance and school growth status. The participants for this study included 102 high school and/or attendance center principals in the state of Mississippi. Of the 102 high school principals who responded to the survey, 78.4% were male and 21.6% were female. The mean length of time in education for the sample was 22.9 years (SD = 9.2). The mean length of time as principal was 8.17 years (SD = 6.59). Of the 102 school principals who responded to the survey, 15%o were principals of Level 2 (Under-performing) schools, 33%) were principals of Level 3 (Successful) schools, 29% were principals of Level 4 (Exemplary) schools, and 25% were principals of Level 5 (Superior-Performing) schools. There were no participants in this study who were principals of a Level 1 or Low-performing school. In addition to school performance levels, school\u27s growth status was also noted. Of the 102 school principals participating in this study, 88.2% are principals of schools that did not meet their growth expectation and 11.8% are principals of schools that met their growth expectation. There were no participants in this study who served at a school that exceeded their growth expectation. The research study was guided by the following questions: 1) Is there a statistically significant relationship between Mississippi high school principals\u27 ratings of self-efficacy relative to the elements of the Balanced Leadership Framework and their schools\u27 performance classifications? 2) Is there a statistically significant relationship between Mississippi high school principals\u27 ratings of self-efficacy relative to the elements of the Balanced Leadership Framework and school growth status? 3) Is there a statistically significant relationship between Mississippi high school principals\u27 ratings of self-efficacy relative to the elements of the Balanced Leadership Framework and student achievement? 4) Is there a statistically significant difference between Mississippi high school principals\u27 perception of change and school performance classification? and 5) Is there a statistically significant relationship between efficacy of delegates\u27 performance as rated by principals using the elements of the Balanced Leadership Framework and schools\u27 performance classification, schools\u27 growth status, and student achievement? Both the leadership self-efficacy rating and delegate performance rating was acquired using the Principal Leadership Self-Efficacy survey. The Principal Leadership Self- Efficacy survey is a 21 question survey adapted from the 21 leadership responsibilities outlined in McREL\u27s Balanced Leadership Framework. Based on these guiding questing a total of 13 hypotheses were tested using Discriminant Function Analysis, Multiple Linear Regression, and Chi-Square tests. Each of the 13 hypotheses was rejected. Although none of the 13 hypotheses were statistically significant, descriptive statistics of the hypotheses did offer valuable insights into principals\u27 ratings of self-efficacy relative to the elements of the Balanced Leadership Framework and school performance. First, it was noted that four of the 21 leadership responsibilities efficacy ratings increased parallel to school performance classifications. Those four responsibilities were Discipline, Order, Outreach, and Visibility. Secondly, regardless of school performance classification or growth status, principals\u27 efficacy rating for the Outreach responsibility was higher than any other leadership responsibility. Thirdly, principals of Level 5 (Superior-performing) schools Knowledge of Curriculum, Instruction, and Assessment efficacy rating was rated lower than any other school performance classification. Finally, principal efficacy ratings of schools who met their growth expectation were lower than those who did not meet their growth expectation in four responsibilities. Those responsibilities were Ideals/Beliefs, Intellectual Stimulation, Involvement in Curriculum, Instruction, and Assessment, and Knowledge of Curriculum, Instruction, and Assessment

    A Systematic Search for Corotating Interaction Regions in Apparently Single Galactic WR Stars. I. Characterizing the Variability

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    We present the results of a systematic search for large-scale spectroscopic variability in apparently single Wolf-Rayet stars brighter than ~12.5. In this first paper we characterize the various forms of variability detected and distinguish several separate groups. For each star in our sample, we obtained 4-5 high-resolution spectra with a signal-to-noise ratio ~100. Our ultimate goal is to identify new candidates presenting variability that potentially comes from Co-rotating Interaction Regions (CIR). Out of a sample of 25 stars, 10 were found to display large-scale changes of which 4 are of CIR-type (WR1, WR115, WR120 and WR134). The star WR134 was already known to show such changes from previous studies. Three WN8 stars present a different type of large-scale variability and we believe deserve a group of their own. Also, all three WC9d stars in our sample present large-scale variability, but it remains to be checked if these are binaries, as many dust-making WR stars are double. Finally, of the remaining stars, 10 were found to show small-amplitude spectral changes which we attribute to normal line-profile variability due to inhomogeneities in the wind, and 5 were found to show no spectral variability, as far as can be concluded from the data in hand. Follow-up studies are required to identify potential periods for our candidates showing CIR-type changes and eventually estimate a rotation rate for these WR stars.Comment: 25 pages, 13 figure

    Nonequilibrium thermodynamics of circulation regimes in optically-thin, dry atmospheres

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    An extensive analysis of an optically-thin, dry atmosphere at different values of the thermal Rossby number Ro and of the Taylor number Ff is per- formed with a general circulation model by varying the rotation rate {\Omega} and the surface drag {\tau} in a wide parametric range. By using nonequilibrium thermodynamics diagnostics such as material entropy production, efficiency, meridional heat transport and kinetic energy dissipation we characterize in a new way the different circulation regimes. Baroclinic circulations feature high mechanical dissipation, meridional heat transport, material entropy pro- duction and are fairly efficient in converting heat into mechanical work. The thermal dissipation associated with the sensible heat flux is found to depend mainly on the surface properties, almost independent from the rotation rate and very low for quasi-barotropic circulations and regimes approaching equa- torial super-rotation. Slowly rotating, axisymmetric circulations have the highest meridional heat transport. At high rotation rates and intermediate- high drag, atmospheric circulations are zonostrohic with very low mechanical dissipation, meridional heat transport and efficiency. When {\tau} is interpreted as a tunable parameter associated with the turbulent boundary layer trans- fer of momentum and sensible heat, our results confirm the possibility of using the Maximum Entropy Production Principle as a tuning guideline in the range of values of {\Omega}. This study suggests the effectiveness of using fun- damental nonequilibrium thermodynamics for investigating the properties of planetary atmospheres and extends our knowledge of the thermodynamics of the atmospheric circulation regimes

    Effect of increasing intraperitoneal infusion rates on bupropion hydrochloride-induced seizures in mice

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    <p>Abstract</p> <p>Background</p> <p>It is not known if there is a relationship between input rate and incidence of bupropion-induced seizures. This is important, since different controlled release formulations of bupropion release the active drug at different rates.</p> <p>Methods</p> <p>We investigated the effect of varying the intraperitoneal infusion rates of bupropion HCl 120 mg/kg, a known convulsive dose<sub>50 </sub>(CD<sub>50</sub>), on the incidence and severity of bupropion-induced convulsions in the Swiss albino mice. A total of 69 mice, approximately 7 weeks of age, and weighing 21.0 to 29.1 g were randomly assigned to bupropion HCl 120 mg/kg treatment by intraperitoneal (IP) administration in 7 groups (9 to 10 animals per group). Bupropion HCl was infused through a surgically implanted IP dosing catheter with infusions in each group of 0 min, 15 min, 30 min, 60 min, 90 min, 120 min, and 240 min. The number, time of onset, duration and the intensity of the convulsions or absence of convulsions were recorded.</p> <p>Results</p> <p>The results showed that IP administration of bupropion HCl 120 mg/kg by bolus injection induced convulsions in 6 out of 10 mice (60% of convulsing mice) in group 1. Logistic regression analysis revealed that infusion time was significant (p = 0.0004; odds ratio = 0.974) and increasing the IP infusion time of bupropion HCl 120 mg/kg was associated with a 91% reduced odds of convulsions at infusion times of 15 to 90 min compared to bolus injection. Further increase in infusion time resulted in further reduction in the odds of convulsions to 99.8% reduction at 240 min.</p> <p>Conclusion</p> <p>In conclusion, the demonstration of an inverse relationship between infusion time of a fixed and convulsive dose of bupropion and the risk of convulsions in a prospective study is novel.</p

    Interplanetary CubeSats: Opening the Solar System to a Broad Community at Lower Cost

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    Interplanetary CubeSats could enable small, low-cost missions beyond low Earth orbit. This class is defined by mass < ~ 10 kg, cost < $30 M, and durations up to 5 years. Over the coming decade, a stretch of each of six distinct technology areas, creating one overarching architecture, could enable comparatively low-cost Solar System exploration missions with capabilities far beyond those demonstrated in small satellites to date. The six technology areas are: (1) CubeSat electronics and subsystems extended to operate in the interplanetary environment, especially radiation and duration of operation; (2) Optical telecommunications to enable very small, low-power uplink/downlink over interplanetary distances; (3) Solar sail propulsion to enable high !V maneuvering using no propellant; (4) Navigation of the Interplanetary Superhighway to enable multiple destinations over reasonable mission durations using achievable !V; (5) Small, highly capable instrumentation enabling acquisition of high-quality scientific and exploration information; and (6) Onboard storage and processing of raw instrument data and navigation information to enable maximum utility of uplink and downlink telecom capacity, and minimal operations staffing. The NASA Innovative Advanced Concepts (NIAC) program in 2011 selected Interplanetary CubeSats for further investigation, some results of which are reported here for Phase 1

    Convulsive liability of bupropion hydrochloride metabolites in Swiss albino mice

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    <p>Abstract</p> <p>Background</p> <p>It is known that following chronic dosing with bupropion HCl active metabolites are present in plasma at levels that are several times higher than that of the parent drug, but the possible convulsive effects of the major metabolites are not known.</p> <p>Methods</p> <p>We investigated the convulsive liability and dose-response of the three major bupropion metabolites following intraperitoneal administration of single doses in female Swiss albino mice, namely erythrohydrobupropion HCl, threohydrobupropion HCl, and hydroxybupropion HCl. We compared these to bupropion HCl. The actual doses of the metabolites administered to mice (n = 120; 10 per dose group) were equimolar equivalents of bupropion HCl 25, 50 and 75 mg/kg. Post treatment, all animals were observed continuously for 2 h during which the number, time of onset, duration and intensity of convulsions were recorded. The primary outcome variable was the percentage of mice in each group who had a convulsion at each dose. Other outcome measures were the time to onset of convulsions, mean convulsions per mouse, and the duration and intensity of convulsions.</p> <p>Results</p> <p>All metabolites were associated with a greater percentage of seizures compared to bupropion, but the percentage of convulsions differed between metabolites. Hydroxybupropion HCl treatment induced the largest percentage of convulsing mice (100% at both 50 and 75 mg/kg) followed by threohydrobupropion HCl (50% and 100%), and then erythrohydrobupropion HCl (10% and 90%), compared to bupropion HCl (0% and 10%). Probit analysis also revealed the dose-response curves were significantly different (p < 0.0001) with CD<sub>50 </sub>values of 35, 50, 61 and 82 mg/kg, respectively for the four different treatments. Cox proportional hazards model results showed that bupropion HCl, erythrohydrobupropion HCl, and threohydrobupropion HCl were significantly less likely to induce convulsions within the 2-h post treatment observation period compared to hydroxybupropion HCl. The mean convulsions per mouse also showed the same dose-dependent and metabolite-dependent trends.</p> <p>Conclusion</p> <p>The demonstration of the dose-dependent and metabolite-dependent convulsive effects of bupropion metabolites is a novelty.</p

    Alcohol significantly lowers the seizure threshold in mice when co-administered with bupropion hydrochloride

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    <p>Abstract</p> <p>Background</p> <p>Bupropion HCl is a widely used antidepressant that is known to cause seizures in a dose-dependent manner. Many patients taking antidepressants will consume alcohol, even when advised not to. Previous studies have not shown any interactions between bupropion HCl and alcohol. However, there have been no previous studies examining possible changes in seizure threshold induced by a combination of alcohol and bupropion HCl.</p> <p>Methods</p> <p>Experimentally naĂŻve female Swiss albino mice (10 per group) received either single doses of bupropion HCl (ranging from 100 mg/kg to 120 mg/kg) or vehicle (0.9% NaCl) by intraperitoneal (IP) injection in a dose volume of 10 ml/kg, and single-dose ethanol alone (2.5 g/kg), or vehicle, 5 min prior to bupropion dosing. The presence or absence of seizures, the number of seizures, the onset, duration and the intensity of seizures were all recorded for 5 h following the administration of ethanol.</p> <p>Results</p> <p>The results show that administration of IP bupropion HCl alone induced seizures in mice in a dose-dependent manner, with the 120 mg/kg dose having the largest effect. The percentage of convulsing mice were 0%, 20%, 30% and 60% in the 0 (vehicle), 100, 110, and 120 mg/kg dose groups, respectively. Pretreatment with ethanol produced a larger bupropion HCl-induced convulsive effect at all the doses (70% each at 100, 110 and 120 mg/kg) and a 10% effect in the ethanol + vehicle only group. The convulsive dose of bupropion HCl required to induce seizures in 50% of mice (CD<sub>50</sub>), was 116.72 mg/kg for bupropion HCl alone (CI: 107.95, 126.20) and 89.40 mg/kg for ethanol/bupropion HCl (CI: 64.92, 123.10).</p> <p>Conclusion</p> <p>These results show that in mice alcohol lowers the seizure threshold for bupropion-induced seizures. Clinical implications are firstly that there may be an increased risk of seizures in patients consuming alcohol, and secondly that formulations that can release bupropion more readily in alcohol may present additional risks to patients.</p
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