Method development, validation, and implementation of Raman spectroscopy as an in-situ process analytical technology for fermentation process development and commercial manufacturing

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Using Performance Assessments to Connect Fractions and Rational Expressions: Noyce Scholars as Mentors to Pre-Service Elementary Teachers

At Georgia Southern University, Noyce scholars are not only being mentored, but they are also serving as mentors to preservice elementary teachers. One topic that proves to be problematic for many students is the conceptual understanding of fractions and rational expressions. Since our Noyce scholars with mathematics degrees will be teaching algebra, it is important that they are fluent with the arithmetic to algebra connection. In addition, it is crucial that these mathematics majors become stakeholders in mathematics education at the elementary school level. Performance assessments can provide the structure necessary for assisting pre-service elementary teachers in firmly establishing the arithmetic to algebra connection. This session showcases a performance assessment where students are not only required to connect concrete models with standard fraction algorithms, but are also required to explain these connections. In this performance assessment, fraction bars are used with the number line in order to establish the arithmetic to algebra connection. Noyce scholars assist by helping and evaluating these pre-service teachers. By participating, not only do Noyce scholars support elementary teachers, but they also gain strategies and resources needed to teach fractions in a way that leads to conceptual understanding

Graduate Chamber Recital:Griffin James & Eric Jordan, Euphoniums Brian Badgley and Paul Nesper, Tubas

Center for the Performing Arts Monday Evening January 31, 2005 8:00p.m

Student Chamber Recital:Graduate Quintet

Kemp Recital Hall Saturday Afternoon December 3, 2005 1:30p.m

Herbicide Retention and Runoff Losses as Affected by Sugarcane Mulch Residue (Bulletin #883)

The purpose of this study was to evaluate the effectiveness of sugarcane residue (mulch cover) in reducing non-point source contamination of applied chemicals from sugarcane fields.https://digitalcommons.lsu.edu/agcenter_bulletins/1019/thumbnail.jp

Patterns of normal transvalvular regurgitation in mechanical valve prostheses

AbstractThe magnitude and spatial distribution of normal leakage through mechanical prosthetic valves were studied in an in vitro model of mitral regurgitation. The effective regurgitant orifice was calculated from regurgitant rate at different transvalvular pressure differences and flow velocities. This effective orifice area was 0.6 to 2 mm2for three tilting disc prostheses (Medtronic-Hall sizes 21, 25 and 29) and 0.2 to 1.1 mm2for three bileaflet valves (St. Jude Medical sizes 21, 25 and 33).In the single disc valves, Doppler color flow examination disclosed a prominent central regurgitant jet around the central hole for the strut, accompanied by minor leakage along the rim of the disc (central to peripheral jet area ratio 3.3 ± 1.2). The bileaflet prostheses showed a peculiar complex pattern: in planes parallel to the two disc axes, convergent peripherally arising jets were visualized, whereas in orthogonal planes several diverging jets were seen.Mounting the disc and bileaflet valves on a water-filled tube allowed reproduction and interpretation of this pattern: for the bileaflet valve, the jets originated predominantly from valve ring protrusions that contained the axis hinge points and created a converging V pattern in planes parallel to the leaflets and a diverging V pattern in orthogonal planes.Similar patterns were observed during transesophageal echocardiography in 20 patients with a normally functioning St. Jude prosthesis. In 10 patients with a Medtronic-Hall valve, a dominant central jet was observed with one or more smaller peripheral jets. The median central to peripheral jet area ratio was 5 to 1.In summary, in two types of mechanical valve prostheses, effective leakage orifice areas are reported and criteria proposed for the differentiation of “physiologic” and pathologic regurgitation based on the spatial configuration of the jets

Left ventricular function after valve repair for chronic mitral regurgitation: Predictive value of preoperative assessment of contractile reserve by exercise echocardiography

Objectives.We evaluated the value of preoperative assessment of left ventricular contractile reserve in predicting ventricular function after valve repair for minimally symptomatic mitral regurgitation.Background.The optimal timing for operation in minimally symptomatic patients with significant mitral regurgitation is controversial. Accurate preoperative assessment of left ventricular function is difficult, and the ability to predict postoperative function is limited. Previous studies in patients undergoing mitral valve replacement may not be applicable in the present era of valve repair.Methods.We performed exercise echocardiography in 139 patients with isolated mitral regurgitation and no coronary disease, 74 of whom subsequently underwent uncomplicated valve repair. We measured rest left ventricular end-systolic dimension, end-systolic wall stress and positive first derivative of left ventricular pressure (dP/dt). End-diastolic and end-systolic volumes and ejection fraction were measured preoperatively at rest, immediately after exercise and postoperatively.Results.Ejection fraction decreased postoperatively to 55 ± 10% from a rest preoperative value of 64 ± 9% (p < 0.001). Compared with patients with a postoperative ejection fraction ≥50% (n = 56), patients with postoperative ejection fraction <50% (n = 18) had a significantly lower preoperative exercise ejection fraction (57 ± 11% vs. 73 ± 9%, p < 0.0005), a larger exercise end-systolic volume index (32 ± 8 vs. 18 ± 7 cm3/m2, p < 0.0005) and a lower change in ejection fraction with exercise (−4 ± 8% vs. 9 ± 10%, p < 0.005). Preoperative rest indexes, including dP/dt, end-systolic wall stress and end-systolic volume index were less predictive, whereas exercise capacity, rest ejection fraction and end-systolic dimension were not predictive of postrepair ejection fraction. An exercise end-systolic volume index >25 cm3/m2 was the best predictor of postoperative dysfunction, with a sensitivity and specificity of 83%.Conclusions.In minimally symptomatic patients with mitral regurgitation, latent ventricular dysfunction may be indicated by a limited contractile reserve, manifest at exercise as an inadequate increase in ejection fraction and a larger end-systolic volume. These variables may also be used to predict left ventricular function after repair

4.48-GHz fractional- N frequency synthesizer with spurious-tone suppression via probability mass redistribution

A 4.48-GHz type-II charge pump fractional-N PLL implemented in a 0.18-μm BiCMOS process is presented. The divider controller's output is processed using a novel block, the probability mass redistributor, which statistically reconfigures the modulation noise such that fractional spurs are minimized. Measurements demonstrate in-band fractional spurs of -80 dBc. The solution, which is a drop-in modification of a conventional MASH structure, incurs a modulator area increase of 22%, and can be used in conjunction with other linearization strategies

Wandering spur suppression in a 4.9-GHz fractional-N frequency synthesizer

Fractional-N frequency synthesizers that use a digital Δ-Σ modulator (DDSM) to control the feedback divider can exhibit spurious tones that move about in the frequency domain; these are known colloquially as ``walking'' or wandering spurs. Building upon a theoretical explanation of the origin of wandering spurs, this article presents two methods to suppress them. It describes a 4.9-GHz 180-nm SiGe BiCMOS charge-pump phase-locked loop (CP-PLL) fractional-N frequency synthesizer platform with a divider controller that can function as: 1) a standard MASH 1-1-1; 2) a MASH 1-1-1 with high-amplitude dither; and 3) a MASH 1-1-1 with a modified third stage. Measurements confirm the effectiveness of the wandering spur suppression strategies