Pedestal bifurcation and resonant field penetration at the threshold of edge-localized mode suppression in the DIII-D Tokamak.

Rapid bifurcations in the plasma response to slowly varying n=2 magnetic fields are observed as the plasma transitions into and out of edge-localized mode (ELM) suppression. The rapid transition to ELM suppression is characterized by an increase in the toroidal rotation and a reduction in the electron pressure gradient at the top of the pedestal that reduces the perpendicular electron flow there to near zero. These events occur simultaneously with an increase in the inner-wall magnetic response. These observations are consistent with strong resonant field penetration of n=2 fields at the onset of ELM suppression, based on extended MHD simulations using measured plasma profiles. Spontaneous transitions into (and out of) ELM suppression with a static applied n=2 field indicate competing mechanisms of screening and penetration of resonant fields near threshold conditions. Magnetic measurements reveal evidence for the unlocking and rotation of tearinglike structures as the plasma transitions out of ELM suppression.

Magnetic-flux pumping in high-performance, stationary plasmas with tearing modes.

Analysis of the change in the magnetic field pitch angles during edge localized mode events in high performance, stationary plasmas on the DIII-D tokamak shows rapid (<1 ms) broadening of the current density profile, but only when a m/n=3/2 tearing mode is present. This observation of poloidal magnetic-flux pumping explains an important feature of this scenario, which is the anomalous broadening of the current density profile that beneficially maintains the safety factor above unity and forestalls the sawtooth instability.

Edge-localized-mode--induced transport of impurity density, energy, and momentum.

High temporal and spatial resolution measurements of impurity dynamics associated with an edge-localized mode (ELM) indicate that the ELM perturbation consists of two distinct parts: a rapid (< 300 micros) expulsion of impurity density at the time of the instability followed by a slower time scale (< 1 ms) decrease in the ion temperature. While the density perturbation remains nearly constant over a wide range of plasma collisionality, the temperature perturbation decreases as the collisionality increases. Analysis of the radial electric field E(r) evolution indicates that the E(r) well normally present in H-mode plasmas is modified strongly by the ELM and that the size of the temperature perturbation is correlated with the associated change in the E x B shear.

Validation of neoclassical bootstrap current models in the edge of an H-mode plasma.

Analysis of the parallel electric field E(parallel) evolution following an L-H transition in the DIII-D tokamak indicates the generation of a large negative pulse near the edge which propagates inward, indicative of the generation of a noninductive edge current. Modeling indicates that the observed E(parallel) evolution is consistent with a narrow current density peak generated in the plasma edge. Very good quantitative agreement is found between the measured E(parallel) evolution and that expected from neoclassical theory predictions of the bootstrap current.

Modification of the current profile in high-performance plasmas using off-axis electron-cyclotron-current drive in DIII-D.

Recent DIII-D experiments using off-axis electron cyclotron current drive (ECCD) have demonstrated the ability to modify the current profile in a plasma with toroidal beta near 3%. The resulting plasma simultaneously sustains the key elements required for Advanced Tokamak operation: high bootstrap current fraction, high beta, and good confinement. More than 85% of the plasma current is driven by noninductive means. ECCD is observed to produce strong negative central magnetic shear, which in turn acts to trigger confinement improvements in all transport channels in the plasma core.

Comparison of fatty acid content of milk from Jersey and Holstein cows consuming pasture or a total mixed ration.

Holstein (n = 19) and Jersey (n = 18) cows were used to study effects of two feeding systems on fatty acid composition of milk. Confinement cows were fed a total mixed ration with corn silage and alfalfa silage and pastured cows grazed a crabgrass (90%) and clover (10%) pasture and were allowed 5.5 kg of grain per head daily. Two milk samples were collected from each cow at morning and afternoon milkings 1 d each week for four consecutive weeks in June and July 1998. One set of milk samples was analyzed to determine fatty acid composition, and the second set was used for crude protein and total fat analyses. Data were analyzed by the general linear models procedure of SAS, using a split-plot model with breed, treatment, and breed x treatment as main effects and time of sampling and week as subplot effects along with appropriate interactions. Milk from pastured cows was higher than milk from confinement cows for the cis-9, trans-11 octadecadienoic acid isomer of conjugated linoleic acid (CLA). Also, milk from Holsteins was higher than milk from Jerseys for C16:1, C18:1, and CLA and lower than Jerseys for C6:0, C8:0, C10:0, C12:0, and C14:0. Several treatment x week interactions existed, but main effects were still important; for example, proportions of CLA in milk of grazed cows were relatively constant across weeks (0.66, 0.64, 0.64, and 0.69% +/- 0.02%, respectively), but the CLA in milk of confinement cows increased in wk 4 (0.35, 0.31, 0.31, and 0.48% +/- 0.02% for wk 1 to 4, respectively). There are potentially important differences in fatty acid composition of milk from cows consuming a warm season pasture species compared with milk from cows consuming a total mixed ration, as well as differences between Holstein and Jersey breeds.

Reliability of the quadriceps angle measurement.

The quadriceps angle (Q-angle) is used to determine patellofemoral alignment. Although this measurement has been used to evaluate and treat patellofemoral joint pathology, few studies have examined its reliability. This study evaluated the interobserver and intraobserver reliability of the Q-angle measurement. To investigate the interobserver reliability of the Q-angle, 25 individuals of varying levels of training served as observers and participants as each measured the other 24 participants. To investigate the intraobserver reliability of the Q-angle, 3 of the observers measured 13 of the participants an additional 2 times. Additionally, clinically derived Q-angle measurements were compared with radiographically derived measurements. The reliability analysis was performed using intraclass correlation coefficients. For interobserver measurements, the intraclass correlation coefficients ranged from 0.17-0.29 for the four variables evaluated (right and left, extension and flexion). For intraobserver measurements, the intraclass correlation coefficients ranged from 0.14-0.37. The average intraclass correlation coefficient between the clinically and radiographically derived measurements ranged from 0.13-0.32. This study demonstrates poor interobserver and intraobserver reliability of Q-angle measurement and poor correlation between clinically and radiographically derived Q-angles.

Inhibition of human angiogenesis with heparin and hydrocortisone.

Angiogenesis is a critical determinant of tumor growth and the development of metastases. Heparin, steroids, and heparin/steroid combinations have been used in a variety of in vitro models and in vivo in animal models as effective inhibitors of angiogenesis. We tested heparin, steroid and heparin/steroid combinations at a variety of concentrations to determine their effect on the human 'angiogenic switch' from a resting to a proliferative endothelium in vessels from three placentas (initiation), and the effect of these compounds on the subsequent growth of a human angiogenic response (promotion). Using full-thickness human placental vein discs cultured in three-dimensional fibrin-thrombin clots, we demonstrated that heparin (300, 3000 micrograms/ml), steroid (350, 3500 micrograms/ml), and combinations of heparin/steroid at these doses effectively blocked both initiation and promotion of a human angiogenic response in a dose-dependent fashion. We also demonstrated that high-dose steroid or heparin/steroid treatment for 15 days resulted in disruption of vessel integrity, while treatment with heparin alone produced a suppressed growth rate but had intact vessel architecture. High-dose heparin/steroid treatment could also disrupt a developed angiogenic response and retard further development of an angiogenic response following the cessation of treatment.

Myocardial texture and cardiac calcification in uremia.

Seventy patients with advanced chronic renal failure were examined by 2D echocardiography in an effort to determine the prevalence of changes in myocardial texture and of valvular calcification. Changes in myocardial texture may be due to calcium deposition in the myocardium, the relationship between changes in myocardial texture and factors that may enhance myocardial calcification (blood levels of parathyroid hormone, PTH, and calcium-phosphorus product) were also evaluated. Myocardial texture was abnormal in 36 patients. In 68 patients, structural calcification could be assessed; a high degree of calcification was found. No correlation was found between either the echocardiographic parameter and blood levels of PTH or calcium-phosphorus product. We conclude that myocardial textural changes and intracardiac calcification are common in chronic renal failure and that these abnormalities do not correlate with blood PTH levels or calcium-phosphorus product.

Community based nurse case managers: a model to meet New Zealand's changing health care needs.

Policy-makers are concerned to find ways to improve the quality, accessibility and continuity of care, contain costs and ultimately to reduce the rate of institutionalisation. The health reform in New Zealand proposes to open up the way for nurses to be more extensively and effectively involved in primary and community based care in order to meet these needs. The role of nurses as community based nurse case managers in the United States is reviewed and demonstrates very clearly not only is the quality of health care enhanced but also the client and fiscal outcomes improved. The challenge from the reform is for nurses to see the opportunities and to take the initiative before it is taken by other disciplines.