Sustaining quality by control of industrial discharges

Sustaining quality by control of industrial discharge

Active shape control by plants in dynamic environments

Plants are a paradigm for active shape control in response to stimuli. For instance, it is wellknown that a tilted plant will eventually straighten vertically, demonstrating the influence of both an external stimulus, gravity, and an internal stimulus, proprioception. These effects can be modulated when a potted plant is additionally rotated along the plant’s axis, as in a rotating clinostat, leading to intricate shapes. We use a previously-derived rod model to study the response of a growing plant and the joint effects of both stimuli at all rotation speeds. In the absence of rotation, we identify a universal planar shape towards which all shoots eventually converge. With rotation, we demonstrate the existence of a stable family of three-dimensional dynamic equilibria where the plant axis is fixed in space. Further, the effect of axial growth is to induce steady behaviors, such as solitary waves. Overall, this study offers new insight into the complex out-of-equilibrium dynamics of a plant in three dimensions and further establishes that internal stimuli in active materials are key for robust shape control

Active shape control by plants in dynamic environments

Plants are a paradigm for active shape control in response to stimuli. For instance, it is well-known that a tilted plant will eventually straighten vertically, demonstrating the influence of both an external stimulus, gravity, and an internal stimulus, proprioception. These effects can be modulated when a potted plant is additionally rotated along the plant's axis, as in a rotating clinostat, leading to intricate shapes. We use a morphoelastic model for the response of growing plants to study the joint effect of both stimuli at all rotation speeds. In the absence of rotation, we identify a universal planar shape towards which all shoots eventually converge. With rotation, we demonstrate the existence of a stable family of three-dimensional dynamic equilibria where the plant axis is fixed in space. Further, the effect of axial growth is to induce steady behaviors, such as solitary waves. Overall, this study offers new insight into the complex out-of-equilibrium dynamics of a plant in three dimensions and further establishes that internal stimuli in active materials are key for robust shape control

Hyperbolic calorons, monopoles, and instantons

We construct families of SO(3)-symmetric charge 1 instantons and calorons on the space H^3 x R. We show how the calorons include instantons and hyperbolic monopoles as limiting cases. We show how Euclidean calorons are the flat space limit of this family.Comment: 11 pages, no figures 1 reference added Published version available at: http://www.springerlink.com/content/k0j4815u54303450

Exercise Induced cardiac troponin elevation:An update on the evidence, mechanism and implications

Post-exercise cardiac troponin (cTn) elevation is a recognised phenomenon which historically has been detected using standard sensitivity assays. More recently high-sensitivity assays have been developed and are now the gold standard for detection of cTn in the clinical setting. Although the assay's enhanced sensitivity confers benefits it has created new challenges for clinicians. By evaluating the change in cTn values over time, taking into account biological and analytical variation, the clinician is able to differentiate between a pathological and normal cTn value. As a result, serial cTn testing has become a fundamental component of the clinical assessment of chest pain patients and is included in the most recent definition for myocardial infarction and the latest guidelines for the management of acute coronary syndromes without persistent ST-segment elevation. A review of the cTn kinetics literature demonstrates a pattern of elevation and peak within the first 4 h after exercise dropping within 24 h. In contrast myocardial necrosis demonstrates a later cTn peak with a slower downslope occurring over several days. Understanding cTn kinetics facilitates clinician's decision making when presented with a chest pain patient post-exercise. Furthermore, it helps elucidate the underlying mechanism and establish the clinical significance of post-exercise cTn elevation, which in all other situations confers negative prognostic value. We recommend serial cTn testing in this scenario with a suggested algorithm included in this review. Keywords: Troponin, Kinetics, Heart, Exercis

Pulse wave analysis in normal pregnancy: a prospective longitudinal study.

Outside pregnancy, arterial pulse wave analysis provides valuable information in hypertension and vascular disease. Studies in pregnancy using this technique show that vascular stiffness is raised in women with established pre-eclampsia. We aimed to establish normal ranges for parameters of pulse wave analysis in normal pregnancy and to compare different ethnic groups

Clinical Correlates and Prognostic Significance of the Ventilatory Response to Exercise in Chronic Heart Failure

AbstractObjectives. This study sought to investigate the clinical characteristics of patients with chronic heart failure and an increased ventilatory response to exercise and to examine the prognostic usefulness of this response.Background. The ventilatory response to exercise is increased in many patients with chronic heart failure and may be characterized by the regression slope relating minute ventilation to carbon dioxide output (V̇e–V̇co2slope) during exercise.Methods. One hundred seventy-three consecutive patients (155 men; mean [±SD] age 59.8 ± 11.5 years; radionuclide left ventricular ejection fraction [LVEF] 28.4 ± 14.6%) underwent cardiopulmonary exercise testing (peak oxygen consumption 18.5 ± 7.3 ml/kg per min; V̇e–V̇co2slope 34.8 ± 10.6) over a 2-year period. Using 1.96 standard deviations above the mean V̇e–V̇co2slope of 68 healthy age-matched subjects (mean slope 26.3 ± 4.1), we defined a high ventilatory response to exercise as a slope >34.Results. Eighty-three patients (48%) had an increased V̇e–V̇co2slope (mean 43.1 ± 8.9). There was a difference in age (62.2 vs. 57.3 years, p = 0.005), New York Heart Association functional class (2.9 vs. 2.1, p < 0.001), LVEF (24.7 vs. 31.9%, p = 0.0016), peak oxygen consumption (14.9 vs. 21.7 ml/kg per min, p < 0.0001) and radiographic cardiothoracic ratio (0.58 vs. 0.55, p = 0.002) between these patients and those with a normal slope. In the univariate Cox proportional hazards model, the V̇e–V̇co2slope was an important prognostic factor (p < 0.0001). In the multivariate Cox analyses using several variables (age, peak oxygen consumption, V̇e–V̇co2slope and LVEF), the V̇e–V̇co2slope gave additional prognostic information (p = 0.018) beyond peak oxygen consumption (p = 0.022). Kaplan-Meier survival curves at 18 months demonstrated a survival rate of 95% in patients with a normal V̇e–V̇co2slope compared with 69% in those with a high slope (p < 0.0001).Conclusions. A high V̇e–V̇co2slope selects patients with more severe heart failure and is an independent prognostic marker. The V̇e–V̇co2slope may be used as a supplementary index in the assessment of patients with chronic heart failure.(J Am Coll Cardiol 1997;29:1585–90