Georgia College & State University

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 & Context (language use). The organization has 950 authors who have published 1591 publications receiving 37027 citations.

Hamstring muscle length and lumbar lordosis in subjects with different lifestyle and work setting: comparison between individuals with and without chronic low back pain.

Abstract: Background and objectives Shortened hamstring muscle length has been noted in persons with low back pain (LBP). Prolonged sitting postures, such as those adopted during different work settings and sedentary lifestyle has been associated with hamstring shortness and LBP. The purpose of this study was to investigate the effect of lifestyle and work setting on hamstring length and lumbar lordosis in subjects with and without LBP and to identify the relationship between hamstring muscles length and lumbar lordosis in individuals with different lifestyle and work setting. Material and method A total of 508 subjects between the ages of 20 and 65 were selected. Subjects were categorized into two groups of individuals with and without LBP. A questionnaire was used to obtain information about the subjects' lifestyle and work setting. Hamstring muscle length and lumbar lordosis were measured in all subjects. Results The results showed no significant difference in the number of subjects with different work setting or lifestyle in individuals with and without LBP. Hamstring muscle length or lumbar lordosis was not affected by type of work setting and lifestyle. Our data showed significant difference in hamstring length and no significant difference in lumbar lordosis between subjects with and without LBP in all categories. Lumbar lordosis was not different between individuals with and without hamstring tightness in normal and LBP subjects with different work setting and lifestyle. Conclusion The findings of this study did not support the assumption that work setting and sedentary lifestyle would lead to hamstring tightness in subjects with LBP. It seems that work setting and lifestyle was not a contributing factor for hamstring tightness in subjects with LBP.

Morphotype variations in subfossil diatom species of Aulacoseira in 24 Michigan Lakes, USA

Abstract: Diatom assemblages preserved in lake sediment records can provide proxy data of past environmental changes in biological conditions. In order to investigate past changes in the environment of north-central Michigan, diatom assemblages were studied in sediment cores retrieved from 24 lakes. Diatoms were analyzed from the 'top' and 'bottom' of each core to reconstruct land-use changes in this area. Aulacoseira taxa were identified and evaluated with light and scanning electron microscopy. Results of these observations showed the presence of some variability of the morphological features within North American species populations. Diatom species composition in surface sediments and differences between tops and bottoms corresponded to changes in land use surrounding the lakes, ranging from predominantly forest and rangeland to urban and agriculturally impacted. Diatom-inferred past conditions revealed that the observed morphotypes probably represent taxa with different ecological preferences. The main factors influencing the variability of these morphotypes are changes in the trophic status of the lakes.

Making the Most of the Daphnia Heart Rate Lab: Optimizing the Use of Ethanol, Nicotine & Caffeine

Abstract: Students commonly test the effects of chemical agents on the heart rate of the crustacean Daphnia magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in Daphnia. Ethanol at 5% and 10% (v/v) reduced mean heart rate to ∼50% and ∼20% of its initial value, respectively. Recovery was rapid after removing 5% ethanol, but recovery from 10% ethanol took 20–30 minutes. Nicotine at 100 µM reversibly increased mean heart rate by ∼20%. Higher concentrations produced varied and sometimes irreversible effects. Caffeine at 0.1%, 0.5%, and 2% (w/v) had no convincing effect on heart rate. Of the three agents tested, nicotine's peculiar effects make it the least useful in an educational setting. Caffeine could be used to emphasize the need for blind observers because it does not increase heart rate in Daphnia. If students find that it does, their bias is revealed. Ethanol produces unambiguous...

An improvement to a Berezin-Li-Yau type inequality

Abstract: In this article we improve a lower bound for (a Berezin-Li-Yau type inequality) that appeared in an earlier paper of Harrell and Yolcu. Here denotes the th eigenvalue of the Klein Gordon Hamiltonian when restricted to a bounded set . can also be described as the generator of the Cauchy stochastic process with a killing condition on . To do this, we adapt the proof of Melas, who improved the estimate for the bound of , where denotes the th eigenvalue of the Dirichlet Laplacian on a bounded domain in