Arkansas Cotton Variety Test 2003

The primary aim of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed dealers establish marketing strategies and assists producers in choosing varieties to plant. In this way, the annual test facilitates the inclusion of new, improved genetic material in Arkansas cotton production

Arkansas Cotton Variety and Strain Tests 1991

Varieties and advanced strains of cotton were evaluated in 1991 by the Arkansas Agricultural Experiment Station. Varieties and some advanced breeding lines were evaluated in the 1991 Arkansas Cotton Variety Test. Entries in the 1991 Commercial Cotton Strain Test included both released varieties that have not been evaluated in Arkansas and advanced breeding lines that may soon be available to producers

Relationship between pulse-wave velocity and arterial elasticity

Pulse wave velocity (PWV) was measured in situ in 11 isolated canine common carotid arteries. Seven arteries exhibited a linear PWV vs. pressure function at pressures ranging from 0 to 200 mmHg. Four arteries yielded a linear relationship between PWV and pressure between 1 and 100 mmHg; for these vessels the relationship was nonlinear at higher pressures. Seven arteries (five from the group which was linear up to 200 mmHg and two from the group which was linear up to 100 mmHg) were excised and pressure/volume measurements were made in vivo. Using pressure/volume data, the Moens-Korteweg equation was evaluated as a predictor of the PWV vs. pressure relationship over the linear region. An expression was developed to enable prediction of the pressure/volume relationship using the coefficients at the linear PWV vs. pressure function, and these predictions were evaluated. We found that, for this range, the Moens-Korteweg equation provides a very good basis for predicting the increase in PWV with increasing bias pressure. In addition, we found that the pressure/volume relationship of common carotid arteries is well represented by an exponential of the form V/V0 = Keαf(P) , which was derived as the inverse solution to the Moens-Korteweg equation

Arkansas Cotton Variety Test 2002

The primary aim of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed dealers establish marketing strategies and assists producers in choosing varieties to plant. In this way, the annual test facilitates the inclusion of new, improved genetic material into Arkansas cotton production. Variety adaptation is determined by evaluation of the varieties and lines at four University of Arkansas research stations located near Keiser, Clarkedale, Marianna, and Rohwer. Tests are duplicated in irrigated and non-irrigated culture at the Keiser and Marianna locations. In 2002, 37 entries were evaluated in the main test and 25 were evaluated in the first-year test. This report also includes the Mississippi County Cotton Variety Test (a large-plot, on-farm evaluation of 12 Round-up Ready varieties) and 12 other on-farm cotton variety tests conducted by the University of Arkansas Cooperative Extension Service

Measurements of Young\u27s Modulus of Elasticity of the Canine Aorta with Ultrasound

We have developed an ultrasonic technique for determining the dynamic Young\u27s modulus of elasticity (E) of the canine aorta in vivo. Young\u27s modulus was measured in the descending thoracic aorta (DTA) and the abdominal aorta (AA) of 12 dogs over a range of mean blood pressures from 40-200 mmHg. The vessels were excised and dynamic moduli were determined in vitro postmortem from pressure-volume curves. The data so obtained were compared to the in vivo values. In vivo and in vitro moduli increased exponentially with mean distending pressure (P). The equation of best fit for these data was of the form E= E0 exp(aP). Constants E0 and a depended on the site of measurement (AA or DTA) and upon the particular animal. In vivo and in vitro moduli were not significantly different in the AA (AA: in vivo E0 = 667 ± 382 mmHg, a = 0.017 ± 0.004 mmHg-1; in vitro E0 = 888 ± 367, a= 0.016 ± 0.002). However, in vivo moduli exceeded in vitro moduli in the DTA. (DTA: in vivo E0 = 687 ± 241, a = 0.016 ± 0.004; in vitro E0 = 349 ± 64, a= 0.018 ± 0.003). The increased stiffness of the DTA compared to the AA in vivo may be due to the in situ tethering of the aorta to the spine by the parietal pleura

Efficacy and safety of the reciprocal pulse defibrillator current waveform

The efficacy and safety of a new defibrillating current waveform, consisting of a low-tilt 5 ms trapezoidal pulse followed closely by a second identical pulse of opposite polarity, was tested m seven isolated, perfused, working canine hearts suspended in an isoresistive, isosmotic shock bath at 37 oC. The efficacy and safety of the reciprocal pulse was compared with a single 5 ms pulse, a single 10 ms pulse, and a dual (unidirectional) 5 ms pulse waveform. The mean threshold average current densities for the 5 ms single pulse, 10 ms single pulse, dual 5 ms pulse, and reciprocal pulse (absolute values) were 50, 38, 36, and 37 mA/cm2, respectively. The corresponding mean threshold energy densities in the shock bath were 2.8, 2.9, 2.9, and 3.1 mJ/cm3. Despite the differences in threshold current density among the waveforms, no differences in safety factor (shock strength for 50 per cent post-shock depression, divided by threshold shock strength) were found among the waveforms. The current safety factors were 5.4, 5.4, 5.6, and 5.5 for the 5 ms single pulse, 10 ms single pulse, dual unidirectional pulse and reciprocal pulse, respectively. The corresponding energy density safety factors were 25, 27, 29, and 27. Thus the use of this reciprocal pulse waveform provides no advantage in efficacy or safety over waveforms of the same total duration

Dynamic Intraesophageal Imaging of the Heart with Ultrasound

Real-time images of the heart from within the esophagus are produced by a new intraesophageal ultrasonic sector scanner. Sixty images per second are displayed on a gray scale CRT in real-time and recorded on standard videotape for review. By interactive positioning of the esophageal probe, heart ventricles, atria, and valves can be visualized and their dynamics can be studied. The esophageal probe comprises four 5 MHz PZT-5 piezoelements of 6.35 mm diameter, mounted on a shaft that rotates at 900 rpm. The piezoelements are pulsed at a 5 kHz rate and the echoes are processed electronically

Dynamic intraesophageal imagining of the heart with ultrasound

Real-time images of the heart from within the esophagus are produced by a new intraesophageal ultrasonic sector scanner. Sixty images per second are displayed on a gray scale CRT in real-time and recorded on standard videotape for review. By interactive positioning of the esophageal probe, heart ventricles, atria, and valves can be visualized and their dynamics can be studied. The esophageal probe comprises four 5 MHz PZT-5 piezoelements of 6.35 mm diameter, mounted on a shaft that rotates at 900 rpm. The piezoelements are pulsed at a 5 kHz rate and the echoes are processed electronically

An animal model for testing automatic defibrillators

A promising therapy for ventricular fibrillation--a life-threatening cardiac arrhythmia--is the implantation of an automatic defibrillator. A critical component of such a device is the system that detects the presence of ventricular fibrillation. Automatic systems for detecting ventricular fibrillation have been tested with arrhythmias produced by electric shocks in normal canine hearts, but have not been tested with spontaneous arrhythmias in hyperirritable hearts. We have developed an animal model to create arrhythmias without electrical stimulation and have used it to test our automatic defibrillator. This model permits evaluation of both reliability to diagnose ventricular fibrillation and reliability to reject other tachyarrhythmias

Yield, Earliness and Fiber Strength of Blends of Cotton (Gossypium hirsutum L.) Cultivars

Pricing of cotton (Gossypium hirsutum L.) has been determined primarily by fiber length and grade, which were manually determined. Implementation of the high volume instrument (HVI) cotton classing system in 1991 allowed other fiber quality parameters to be objectively and rapidly measured (Deussen, 1989). One quality parameter added to the pricing structure by the advent of HVI in determining the value of ginned lint is fiber strength (Table 1). Open-end spinning, a new technology being utilized by the textile industry, requires high-strength cotton fibers (\u3e25 g/tex) for manufacture of yarns. As this technology becomes more widely used, cotton with weaker fiber strength will become less desirable, and cotton grown in Arkansas may become less preferred b