The exit velocity of a compressed air cannon

The use of compressed air cannons in an undergraduate lab provides a way to illustrate the cooperation of diverse physics concepts, such as conservation of momentum, the work-kinetic energy theorem, expansion of gas, air drag, and elementary Newtonian mechanics. However, recent proposals have disagreed as to whether the expansion of the gas in the cannon should be modeled as an adiabatic or an isothermal process. We built an air cannon that utilized a diaphragm valve to release our pressurized gas and found that neither model accurately predicted the exit velocity of our projectile. We present a new model, based on the flow of air through the valve, that is in much better agreement with our data

Labeled nitrogen fertilizer research with urea in the semi-arid tropics 3. Field studies on alfisol

Field studies with bordered microplots were conducted on an Alfisol in the semiarid tropics of India to determine (1) the fate of15N-labeled urea applied to dryland sorghum in two successive rainy seasons and (2) the effect of method of application on N fertilizer efficiency. Recoveries of15N-labeled fertilizers by above-ground plant parts ranged from 46.7% to 63.6% in 1981 when the rainfall was above the average and from 54.4% to 66.9% in 1980 when the rainfall was near the average. Small (0.014 g) pellets of urea applied twice as postemergent applications in separate 5 cm deep bands were more effective than single preemergent applications either surface applied or incorporated. Both banding and the split applications contributed to overall fertilizer efficiency. Large (1.0 g) pellets of urea (supergranules) placed at a depth of 5 cm were also superior to the incorporated, small-pellet treatment in 1981. The15N-balance data for the soil (0–90 cm in depth)-plant system in 1981 showed that the unaccounted-for fertilizer N ranged from 5.1% to 20.6%. An important finding was that high grain yields, in excess of 6,000 kg/ha, with N fertilizer losses of less than 10% could be obtained through fertilizer management during a very wet season. The data from the Alfisol experiments were compared with data from similar Vertisol experiments; N fertilizer losses resulting from incorporated and surface applications were greater for Vertisols than for Alfisols in the wetter year

The effect of chronic quercetin supplementation on bone health in postmenopausal women: A double-blind placebo-controlled investigation

Currently, there is limited research investigating the effects of quercetin on bone turnover and density. Therefore, this study aimed to examine the efficacy of 90-day quercetin supplementation on bone turnover, inflammation, body composition, and physical function in postmenopausal women. Thirty-four healthy postmenopausal women (59.2 ± 7.0 yrs, 80.7 ± 15.6 kg, 29.8 ± 6.1 kg⸱m2) participated in the double-blind placebo-controlled investigation. Participants were randomly assigned to one of two groups: 500 mg of Q or 500 mg of fiber (placebo; PLB). Data collected during the pre-and post-supplementation assessments included: bone turnover (osteocalcin, P1NP, CTX), inflammation markers (IL-6, TNF-alpha, CRP), body composition, dominant handgrip strength, and timed up and go test. Independent samples t-tests were used for between-group comparisons of baseline values and the percent change for each dependent variable. A significant difference in percent change for osteocalcin (Q: 20.5±25.7; PLB: 1.3±17.2; p=0.016; d=0.89), P1NP (Q: 28.9 (6.0–57.3); PLB: 4.6 (-7.6 – 8.5); p=0.030; d=0.64), and CTX (Q: 39.0 (-10.0 – 84.6); PLB: -7.74 (-28.9 – 18.5); p=0.023; d=0.91) was found between Q and PLB, with greater increases in Q. Changes in the inflammation markers IL-6 (Q: -17.6±24.1; PLB: 2.90±31.1; p=0.045; d=0.73) and TNF-alpha (Q: -4.9± (-15.3 – [-3.2]); PLB: 1.9 (-7.8 – 4.0); p=0.021; d=0.90) between the two groups were significant. No significant changes were found between groups for CRP, body composition, and physical function (p\u3e0.05). The data suggest that Q may improve bone health status in postmenopausal women through its ability to decrease pro-inflammatory mediators and increase turnover markers

The Effect of Quercetin on Bone Turnover Markers, Inflammatory Markers, and Bone Mineral Density in Postmenopausal Women: A Double-Blind Placebo-Controlled Investigation

Maintaining optimal bone health prevents major bone disorders (e.g., osteoporosis) and prolongs longevity. Quercetin is a plant-based flavonoid that is suggested to have anti-inflammatory effects and may improve bone health. PURPOSE: To investigate the effects of quercetin supplementation over 90-days on prominent bone turnover markers (BTMs), inflammatory markers, bone mineral density (BMD), body composition, and physical functioning in postmenopausal women. METHODS: Thirty-three healthy, nonosteoporotic, postmenopausal women (59.2±7.0 years) participated in a double-blind, placebo-controlled investigation. Participants were randomized into one of two supplement groups: 1) 500 mg of quercetin (QUE) once daily or 2) 500 mg of methylcellulose (placebo; PLB) once daily. Pre- and post-testing visits included assessments of BTMs (i.e., osteocalcin [OC], procollagen type-I N-terminal propeptide [PINP], and type-I collagen cross-linked C-terminal telopeptide [CTX]), inflammatory markers (i.e., interleukin [IL]-6, tumor necrosis factor-alpha [TNF-a], and C-reactive protein [CRP]), BMD measurements, body composition measurements (i.e., body fat percentage), and physical function. RESULTS: The QUE group increased OC (p=0.016; d=0.89), PINP (p=0.030; d=0.64), and CTX (p=0.023; d=0.91) levels and decreased IL-6 (p=0.045; d=0.73) and TNF-a (p=0.021; d=0.90) levels compared to PLB. CRP (p=0.448; d=0.34), BMD, body composition, and physical function remained unchanged. CONCLUSION: The results indicate that QUE may maintain optimal bone health by mediating bone formation and decreasing pro-inflammatory cytokines

Labeled nitrogen fertilizer research with urea in the semi-arid tropics II. Field studies on a Vertisol

Field studies were conducted on Indian Vertisol to determine the fate of15N-labeled fertilizers applied to dryland sorghum in two successive rainy seasons. In the 1981 season, a split-band (SB) urea application of 74 kg N/ha, half amounts placed 5 cm deep and 8 cm from opposite sides of plant rows at 4 and 19 days after emergence, was superior to preemergent applications of either surface-applied (S) or incorporated (I) applications at the same rate; 907 mm of rainfall fell during the sorghum growing period. Percentages of applied N recovered in the soil-plant system after the sorghum harvest were 94%, 74%, and 72%, respectively, for the SB, I, and S application methods. Substantial quantities, 39%, 45%, and 42% of the added N for the SB, I, and S tretments, respectively, remained in the soil after the final harvest. Plant utilization of added urea-N was greater in 1980 when rainfall during the growing season was 212 mm less than in 1981. S or I applications of urea at 74 kg N/ha, with above-ground plant15N recoveries of 48.0% and 48.6%, respectively, were also equally as efficient during 1980. Residual soil N derived from fertilizer was of little value for a sorghum crop in the following rainy season and for a safflower crop in the post-rainy season in a double-cropping system

A pilot study of the King LT supralaryngeal airway use in a rural Iowa EMS system

Introduction In 2003, the King Laryngeal Tube (LT) received FDA approval for US sales. Prehospital systems in urban setting have begun evaluating and adopting the LT for clinical airway management. However, it is not routinely approved by State EMS Boards for use by all prehospita

Strength and hypertrophy responses to constant and decreasing rest intervals in trained men using creatine supplementation

<p>Abstract</p> <p>Background</p> <p>The purpose of the current study was to compare strength and hypertrophy responses to resistance training programs that instituted constant rest intervals (CI) and decreasing rest intervals (DI) between sets over the course of eight weeks by trained men who supplemented with creatine monohydrate (CR).</p> <p>Methods</p> <p>Twenty-two recreationally trained men were randomly assigned to a CI group (n = 11; 22.3 ± 1 years; 77.7 ± 5.4 kg; 180 ± 2.2 cm) or a DI group (n = 11; 22 ± 2.5 years; 75.8 ± 4.9 kg; 178.8 ± 3.4 cm). Subjects in both groups supplemented with CR; the only difference between groups was the rest interval instituted between sets; the CI group used 2 minutes rest intervals between sets and exercises for the entire 8-weeks of training, while the DI group started with a 2 minute rest interval the first two weeks; after which the rest interval between sets was decreased 15 seconds per week (i.e. 2 minutes decreasing to 30 seconds between sets). Pre- and post-intervention maximal strength for the free weight back squat and bench press exercises and isokinetic peak torque were assessed for the knee extensors and flexors. Additionally, muscle cross-sectional area (CSA) of the right thigh and upper arm was measured using magnetic resonance imaging.</p> <p>Results</p> <p>Both groups demonstrated significant increases in back squat and bench press maximal strength, knee extensor and flexor isokinetic peak torque, and upper arm and right thigh CSA from pre- to post-training (p ≤ 0.0001); however, there were no significant differences between groups for any of these variables. The total volume for the bench press and back squat were significantly greater for CI group versus the DI group.</p> <p>Conclusions</p> <p>We report that the combination of CR supplementation and resistance training can increase muscular strength, isokinetic peak torque, and muscle CSA, irrespective of the rest interval length between sets. Because the volume of training was greater for the CI group versus the DI group, yet strength gains were similar, the creatine supplementation appeared to bolster adaptations for the DI group, even in the presence of significantly less volume. However, further research is needed with the inclusion of a control group not receiving supplementation combined and resistance training with decreasing rest intervals to further elucidate such hypotheses.</p

Developing the practice context to enable more effective pain management with older people: an action research approach

Background\ud \ud This paper, which draws upon an Emancipatory Action Research (EAR) approach, unearths how the complexities of context influence the realities of nursing practice. While the intention of the project was to identify and change factors in the practice context that inhibit effective person-centred pain management practices with older people (65 years or older), reflective critical engagement with the findings identified that enhancing pain management practices with older people was dependent on cultural change in the unit as a whole. \ud \ud Methods\ud \ud An EAR approach was utilised. The project was undertaken in a surgical unit that conducted complex abdominal surgery. Eighty-five percent (n = 48) of nursing staff participated in the two-year project (05/NIR02/107). Data were obtained through the use of facilitated critical reflection with nursing staff. \ud \ud Results\ud \ud Three key themes (psychological safety, leadership, oppression) and four subthemes (power, horizontal violence, distorted perceptions, autonomy) were found to influence the way in which effective nursing practice was realised. Within the theme of 'context,' effective leadership and the creation of a psychologically safe environment were key elements in the enhancement of all aspects of nursing practice. \ud \ud Conclusions\ud \ud Whilst other research has identified the importance of 'practice context' and models and frameworks are emerging to address this issue, the theme of 'psychological safety' has been given little attention in the knowledge translation/implementation literature. Within the principles of EAR, facilitated reflective sessions were found to create 'psychologically safe spaces' that supported practitioners to develop effective person-centred nursing practices in complex clinical environments