Echocardiographically-Derived Septal Positional Angle (EDSPA) as a Measure of Elevated Right Ventricular Systolic Pressure

Background: Pulmonary hypertension is a significant yet rare disease that can have many long-term consequences, including death. Cardiac catheterization is the gold standard for measuring pulmonary artery mean pressures (PAMP), but is invasive and risks potentially serious complications. This study aimed to create a semi-quantitative, non-invasive measure of PAMP using septal positioning. Methods: This study was a retrospective study of patients with and without pulmonary hypertension who had a transthoracic echocardiogram and cardiac catheterization. Patients undergoing atrial septal defect closure represented controls. Two blinded readers calculated the “Echocardiographically-Derived Septal Positional Angle (EDSPA)” which was compared to corresponding catheterization data including mean pulmonary artery pressures. Results: A total of 159 children were included, of which 151 had useable echocardiographic data. 40 children were identified as having pulmonary hypertension while 111 children had an atrial septal defect. Patient age ranged from a minimum of 54 days and maximum of 19 years [mean 7.1 years (SD=5.30)]. Inter-observer variability between two readers [Pearson correlation coefficient of 0.939 (p <0.001)] and intra-observer variability were low [intraclass correlation coefficient (ICC) of 0.95 and 0.96 for each observer respectively]. An EDSPA of ≤39° predicted a PAMP>20 mmHg (as measured by cardiac catheterization) with a 76% sensitivity and 76% specificity (AUC 0.846). Conclusions: EDSPA is a useful, non-invasive, and reproducible echocardiographic measure of PAMP that is easy to perform. With a sensitivity and specificity near 80%, it has significant utility in screening for pulmonary hypertension and determining which patients should undergo further invasive diagnostic testing.

Focal length determination for the 60cm telescope at Astronomical station Vidojevica

The focal length of a telescope is an important parameter in determining the angular pixel size. This parameter is used for the purpose of determining the relative coordinates (angular separation and positional angle) of double and multiple stars, and the precise coordinates of extragalactic radio sources (ERS) that are visible at optical wavelengths. At the Astronomical Station Vidojevica we have collected observations of these objects using two CCD cameras, Apogee Alta U42 and SBIG ST-10ME, attached to the 60 cm telescope. Its nominal focal length is 600 cm as given by the manufacturer. To determine the telescope focal length more precisely for both attached detectors, we used angular-separation measurements from CCD images taken at Astronomical Station Vidojevica. The obtained focal lengths are: F42 = (5989 ? 7) mm using the CCD camera Apogee Alta U42 attached to the telescope, and F10 = (5972 ? 4) mm with the CCD camera SBIG ST-10ME attached to the telescope.

Effect of the Guide-Roll Positional Angle to the Stability of Radial Ring Rolling

Non-stability factors affect stability of radial ring rolling process, and lead to fluctuating of ring position. This decreases rolling precision. Evaluating stability of the process is very important. A stability evaluating method is proposed. The stability can be measured with the mean square root of sequence of oscillation of ring geometrical centerline displacement. Using ABAQUS/Explicit, the stability is analyzed. It is showed that guide-roll position angle has the significant effect to the stability. If guide-roll is located at the tangential position to the ring’s fringe, the stability will vary with the angle between two planes. One passes through axes of guide roll and ring blank, and another passes through axes of drive roll and ring blank. The stability is highest when guide roll is situated at the position angle of 100˚to 130˚at exit side of ring rolling mill.

Augmented respiration in a flying insect

The properties of the gas transport system in a tethered flying insect were investigated by directly measuring the oxygen partial pressure (PO2) in a wing muscle of the sweet potato hawkmoth Agrius convolvuli using a needle electrode. At rest, a distribution of PO2 corresponding to levels in the muscle and tracheal structures was observed. At the onset of tethered flight, PO2 in the muscle decreased. However, during a long stable flight, PO2 increased and reached a plateau approximately 2 min after the onset of flight. During stable tethered flight, PO2 in the centre of the second layer of the dorsal longitudinal muscle was locally higher than that during rest. As wing amplitude increased, PO2 increased in spite of the concurrent increase in metabolic rate. During tethered flight at a constant wing amplitude, PO2 was proportional to the mean wing positional angle. The results suggest that this insect effectively uses muscle movement, which increases the frequency and stroke volume of ventilation, to augment gas exchange during flight.

CCD-observations of asteroids: Accuracy and the nearest perspectives for application of the Laplacian orbit determination method

The modern crowded CCD-observations of the Solar system small bodies are very effective and accurate. They easily provide close positions on a short topocentric arc for any celestial body – from several hours during one night to several successive nights at a single observatory. It is obvious, now, that the informational value of such short arc observations is very high. Statistical treatment of these accurate near positions gives an opportunity to calculate the first and second derivatives of spherical asteroid coordinates or an angular topocentric velocity and its positional angle, a topocentric angular acceleration and a curvature of visible trajectory of observed celestial body.

Biomechanics of Flight in Neotropical Butterflies: Morphometrics and Kinematics

Wing and body kinematics of free cruising flight are described for 37 species of Panamanian butterflies ranging over two orders of magnitude in body mass. Butterflies exhibit considerable diversity in body and wing shape, but morphological design is, in general, isometric. Wing loading and mean body diameter show positive allometry. The cruising flight of butterflies is characterized by low wingbeat frequencies (here averaging 11 Hz), stroke amplitudes averaging 103°, and forward speeds in excess of 1m s−1. Body angles during flight are close to horizontal, and stroke plane angles are correspondingly high. Advance ratios are typically greater than 0.9, indicating that the forward and flapping velocity vectors are of comparable magnitude. Flight speed scales with morphological parameters in general accordance with predictions based on isometric design. Interspecifically, no consistent correlation exists between wing kinematics and absolute flight speed. However, maximum positional angle and stroke amplitude tend to increase while body angle decreases with increased relative flight speed.