Imaging and reconstruction of positive streamer discharge tree structures

Streamer discharges often exhibit branching, which can greatly affect their behavior and will lead to so-called streamer trees. In this work we present a methodology for investigating the structure of a streamer discharge tree by means of advanced imaging techniques. Stereoscopic and stroboscopic techniques augment the images with depth perception and temporal information relevant to study the inherently stochastic three-dimensional and transient streamers. A semi-automated post processing algorithm is developed to make a reconstruction of the streamer discharge tree formation. This results in a tree of streamer segments, separated by branching events, where velocities, diameters and trajectories are used to characterize the morphology. The workings of the algorithm is detailed using an exemplar measurement series of positive streamers in synthetic air at 233 mbar.</p

An explicit partition of the fusion-like cross section

The evaporation residue cross section for fusion-like reactions of 309 MeV 14N+159Tb has been decomposed into cross sections for complete fusion and a number of specific incomplete fusion channels using a novel technique involving light-particle-KX-ray coincidences. With this partition it is possible to successfully describe the incomplete momentum transfer observed in velocity spectra of evaporation residues from a very similar system

Generation and division of excitation energy in heavy-ion collisions studied by measuring charged-particle survival fractions

Charged-particle survival fractions of primary projectile-like fragments from the 40Ar + 197Au reaction at 450 MeV were measured by using a large array of 32 phoswich detectors operating in coincidence with a detector of projectile-like fragments. Differential survival fractions of the primary pickup and stripping reaction products indicate a dependence of the average excitation energy generated in the primary fragments on the direction of the mass transfer

Quality of Life and Depressive Symptoms in the Elderly:A Comparison Between Patients With Heart Failure and Age- and Gender-Matched Community Controls

Background: Comparisons of heart failure (FIF) patients with an unselected healthy sample in terms of quality of life (QoL) and depressive symptoms might prove misleading. We compared QoL, and depressive symptoms of a HF population with an age- and gender-matched sample of community dwelling elderly. Methods and Results: Data were collected from 781 HF patients (36% female., age 72 +/- 9; New York Heart Association II-IV) and 781 age- and gender-matched community-dwelling elderly. Participants Completed the Medical Outcome Study 36-item General Health Survey, the Cantril's Ladder of life, and the Center for Epidemiological Studies-Depression scale (CES-D). Analysis of variance techniques e with Welch F test and chi-square tests were used to describe differences in QoL and depressive symptoms between different groups. For both men and women with HF, QoL was reduced and depressive symptoms were elevated when compared with their elderly counterparts (CES-D >= 16: 39% vs. 21 %, P <.001). HF patients had more chronic conditions--specifically diabetes and asthma/chronic obstructive pulmonary disease. Impaired QoL and depressive symptoms were most prevalent among HF patients with comorbidities. Prevalence was also higher in HF patients in the absence of these conditions. Conclusions: HF has it large impact on QoL and depressive symptoms, especially in women with HF. Differences persist, even in the absence of common comorbidities. Results demonstrate the need for studies of representative HF patients with direct comparisons to age- and gender-matched controls. (J. Cardiac Fail 2009;15:17-23

Quantitative modeling of streamer discharge branching in air

Streamer discharges are the primary mode of electric breakdown of air in lightning and high voltage technology. Streamer channels branch many times, which determines the developing tree-like discharge structure. Understanding these branched structures is for example important to describe streamer coronas in lightning research. We simulate branching of positive streamers in air using a 3D fluid model where photoionization is included as a discrete and stochastic process. The probability and morphology of branching are in good agreement with dedicated experiments. This demonstrates that photoionization indeed provides the noise that triggers branching, and we show that branching is remarkably sensitive to the amount of photoionization. Our comparison is therefore one of the first sensitive tests for Zheleznyak's photoionization model, confirming its validity

Time-course of depressive symptoms in patients with heart failure

Background It is unclear how depressive symptoms in patients with heart failure develop over time and whether this trajectory of depressive symptoms is associated with hospital admission and prognosis. Aim To describe the time-course of depressive symptoms and determine the relationship with hospitalisation and mortality. Method Data was analysed using 611 patients with completed CES-D questionnaires at baseline and at 18 months. Data on hospitalisation was collected 18 months after discharge and data on mortality was collected 18 and 36 months post-discharge. Results A total of 140 (61%) of the 229 patients with depressive symptoms at discharge had recovered from depressive symptoms after 18 months whereas 71 (18%) of the 382 non-depressed developed depressive symptoms and 89 (39%) of the 229 depressed remained depressed. Patients with recently (i.e. during the last 18 months) developed depressive symptoms showed a significantly higher risk for cardiovascular hospitalisation (HR 1.7, 95% CI 1.1–2.6, P = .016). After 36 months, patients with developed depressive symptoms after discharge were at a higher risk of all-cause mortality (HR 2.0, 95% CI 1.2–3.5, P = .012) and there was a trend towards a higher risk of all-cause mortality in patients with ongoing depressive symptoms (HR 1.7, 95% CI 0.98–3.1, P = .056). Conclusion A significant proportion of patients with HF, who were reported depressive symptoms at discharge recovered from depressive symptoms during the following 18 months. However, patients who remained having depressive symptoms or patients who developed depressive symptoms had a worse prognosis