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Institution

Georgia College & State University

EducationMilledgeville, Georgia, United States
About: Georgia College & State University is a education organization based out in Milledgeville, Georgia, United States. It is known for research contribution in the topics: Population & Higher education. The organization has 950 authors who have published 1591 publications receiving 37027 citations.


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Journal ArticleDOI
TL;DR: A high performance liquid chromatographic method for the analysis of chlortetracycline (CTC) using postcolumn fluorescence detection has been developed and can be detected in milk at 0.04 micrograms/mL, which is comparable to that obtained by microbiological assays.
Abstract: A high performance liquid chromatographic method for the analysis of chlortetracycline (CTC) using postcolumn fluorescence detection has been developed. After chromatographic separation of CTC on a polystyrene-divinylbenzene copolymer column, a highly fluorescent derivative isochlortetracycline (iso-CTC) was formed postcolumn in an on-line reaction coil with the addition of 25% NaOH (w/v). Chromatographic separation was achieved on a PRP-1 column, 15 cm x 4.6 mm, with 27:73 acetonitrile:0.2% perchloric acid (v/v), at 1.0 mL/min. Fluorescence derivatization was achieved by the on-line addition of 25% NaOH (w/v), at a flow rate of 0.2 mL/min, into the column eluant in a post-column reaction coil. The reaction coil was 9 m of teflon (1/16 in o.d., 0.3 mm i.d.) knitted into a six-sided coil. The fluorescent derivative was detected at lambda ex 355 nm and lambda em > 389 nm. Using this method after a simple sample cleanup, CTC can be detected in milk at 0.04 micrograms/mL, which is comparable to that obtained by microbiological assays. The detection method was linear between 0.02 micrograms/mL and 4 micrograms/mL. Because of the chromatographic separation, the method is more selective than microbiological assays and more sensitive than ultraviolet detection. With the chromatographic system described, the keto tautomeric forms of CTC and 4-epi-CTC are separated in a system which minimizes their formation on-column. In acidic aqueous organic solutions, the keto tautomer of CTC is the only product formed to any significant amount.

31 citations

Journal ArticleDOI
05 Mar 2018-Chaos
TL;DR: In this paper, the effect of demographic stochasticity, in the form of Gaussian white noise, in a predator-prey model with one fast and two slow variables is studied.
Abstract: The effect of demographic stochasticity, in the form of Gaussian white noise, in a predator-prey model with one fast and two slow variables is studied. We derive the stochastic differential equations (SDEs) from a discrete model. For suitable parameter values, the deterministic drift part of the model admits a folded node singularity and exhibits a singular Hopf bifurcation. We focus on the parameter regime near the Hopf bifurcation, where small amplitude oscillations exist as stable dynamics in the absence of noise. In this regime, the stochastic model admits noise-driven mixed-mode oscillations (MMOs), which capture the intermediate dynamics between two cycles of population outbreaks. We perform numerical simulations to calculate the distribution of the random number of small oscillations between successive spikes for varying noise intensities and distance to the Hopf bifurcation. We also study the effect of noise on a suitable Poincare map. Finally, we prove that the stochastic model can be transformed into a normal form near the folded node, which can be linked to recent results on the interplay between deterministic and stochastic small amplitude oscillations. The normal form can also be used to study the parameter influence on the noise level near folded singularities.

31 citations

Journal ArticleDOI
TL;DR: The energy levels of these polymers indicate that the incorporation of benzobisoxazoles into the polymer backbone is a promising strategy for the synthesis of new materials.
Abstract: Herein we report the synthesis of two solution processible, conjugated polymers containing the benzobisoxazole moiety. The polymers were characterized using 1H NMR, UV-Vis and fluorescence spectroscopy. Thermal gravimetric analysis shows that the polymers do not exhibit significant weight loss until approximately 300 °C under nitrogen. Cyclic voltammetry shows that the polymers have reversible reduction waves with estimated LUMO levels at −3.02 and −3.10 eV relative to vacuum and optical bandgaps of 2.04–2.17 eV. Devices based on blends of the copolymers and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) exhibited modest power conversion efficiencies. Theoretical models reveal that there is poor electron delocalization along the polymer backbone, leading to poor performance. However, the energy levels of these polymers indicate that the incorporation of benzobisoxazoles into the polymer backbone is a promising strategy for the synthesis of new materials.

31 citations

Journal ArticleDOI
TL;DR: The measurement issues involved in assessing competence include selecting an appropriate measurement paradigm, selecting accurate measurement instruments, and interpreting the measurement data.
Abstract: Purpose Promoting continued competence in nursing practice has always been of concern to staff development and continuing education educators. Recently it has reached new levels of significance. As a result of the proposals made by the Pew Commission Taskforce on Health Care Workforce Regulation and the National Council of State Boards of Nursing, the profession is re-examining the question, "How do we promote and assure continued competence?" The purpose of this article is to examine the measurement issues related to answering this question. Findings The nursing literature provides several definitions of competence, but none are operational. To measure a concept it must be operationalized. Mandatory continuing education, peer review, and practice or process audits have been used to assess continued competence. The measurement issues involved in assessing competence include selecting an appropriate measurement paradigm, selecting accurate measurement instruments, and interpreting the measurement data. Implications Staff development educators and nurse managers should collaborate in the establishment of standards of practice, the identification of essential competencies specific to the setting, and the development of appropriate methods of measurement of these competencies.

31 citations

Journal ArticleDOI
TL;DR: In this paper, a snake from Lemoyne Quarry is described as new (Arizona voorhiesi), and the fossil record of Arikareean through Blancan (Miocene through Pliocene) snake genera from midcontinental North America suggests erycinine boids became extinct across the region by late Hemphillian time, and colubrid snakes became generically modern by early Blancan time.
Abstract: Middle and late Hemphillian (late Miocene) snakes from Nebraska were identified and interpreted. The mid-Hemphillian (ca. 7 Ma) Lemoyne Quarry of Keith Co., SW Nebraska yielded at least two boid, thirteen colubrid and two viperid snakes. The late Hemphillian (ca. 5 Ma) Devils Nest (Knox Co.), Santee (Knox Co.), and Mailbox Prospect (Antelope Co.) sites of NE Nebraska together yielded at least nine colubrids and one viperid snake. Twenty-four percent of the 16 mid-Hemphillian snake genera and 67% of the 12 species are extinct. Of the 9 genera and 7 species of late Hemphillian snakes, only Paleoheterodon tiheni is extinct. A snake from Lemoyne Quarry is described as new (Arizona voorhiesi). With this new information, the fossil record of Arikareean through Blancan (Miocene through Pliocene) snake genera from midcontinental North America suggests erycinine boids became extinct across the region by late Hemphillian time, and colubrid snakes became generically modern by early Blancan time. These event...

31 citations


Authors

Showing all 957 results

NameH-indexPapersCitations
Gene H. Brody9341827515
Mark D. Hunter5617310921
James E. Payne5220112824
Arash Bodaghee301222729
Derek H. Alderman291213281
Christian Kuehn252063233
Ashok N. Hegde25482907
Stephen Olejnik25674677
Timothy A. Brusseau231391734
Arne Dietrich21443510
Douglas M. Walker21762389
Agnès Bischoff-Kim2146885
Uma M. Singh20401829
David Weese20461920
Angeline G. Close20351718
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20233
20225
202168
202061
201972
201861