2,516 research outputs found
Kinetic equations for Stark line shapes
The BBGKY formalism is revisited in the framework of plasma spectroscopy. We
address the issue of Stark line shape modeling by using kinetic transport
equations. In the most simplified treatment of these equations, triple
correlations between an emitter and the perturbing charged particles are
neglected and a collisional description of Stark effect is obtained. Here we
relax this assumption and retain triple correlations using a generalization of
the Kirkwood truncature hypothesis to quantum operator. An application to
hydrogen lines is done in the context of plasma diagnostic, and indicates that
the neglect of triple correlations can lead to a significant overestimate of
the line width.Comment: 13 pages, 1 figur
Kerr effect as a tool for the investigation of dynamic heterogeneities
We propose a dynamic Kerr effect experiment for the distinction between
dynamic heterogeneous and homogeneous relaxation in glassy systems. The
possibility of this distinction is due to the inherent nonlinearity of the Kerr
effect signal. We model the slow reorientational molecular motion in
supercooled liquids in terms of non-inertial rotational diffusion. The Kerr
effect response, consisting of two terms, is calculated for heterogeneous and
for homogeneous variants of the stochastic model. It turns out that the
experiment is able to distinguish between the two scenarios. We furthermore
show that exchange between relatively 'slow' and 'fast' environments does not
affect the possibility of frequency-selective modifications. It is demonstrated
how information about changes in the width of the relaxation time distribution
can be obtained from experimental results.Comment: 23 pages incl. 6 figures accepted for publication in The Journal of
Chemical Physic
How much is the indoor comfort of a residential building worth? A discrete choice experiment
Generally, people spend most of their time indoors, and the COVID-19 pandemic has further increased the amount of time people spent at home, owing to the widespread adoption of remote work. Consequently, there has been a heightened interest in indoor comfort, including thermal, visual, and acoustic comfort and indoor air quality. This interest has prompted a need to understand the economic value of each aspect of indoor comfort. To address this, a discrete choice experiment (DCE) was performed to estimate the willingness to pay (WTP) for advanced technological solutions that provide greater comfort than basic solutions in residential housing. The research showed a significant WTP for all aspects of comfort, with the greatest appreciation for thermal comfort. Additionally, the WTP for each aspect of comfort was greater than the additional costs required to implement advanced technological solutions to enable the desired comfort. The findings demonstrated that the sample population, mostly comprising people under the age of forty, was highly sensitive to comfort considerations and the related benefits derived from energy-efficient solutions. Specifically, comparing the WTP of the different aspect of comfort and the total one identified, the following relative importance was found: 51 % for thermal comfort (WTP = 377.94 EUR/m2); 22 % for visual comfort (WTP = 166.83 EUR/m2); 16 % for acoustic comfort (WTP = 119.60 EUR/m2) and 11 % for indoor air quality (WTP = 79.21 EUR/m2). These motivations can guide future decision-making and designers in the building market
Mind the gap: an administrative data analysis of dental treatment outcomes and severe mental illness
Samuel D. Gross, M.D. (1805-1884): an innovator, even in death.
Dr. Samuel Gross\u27 contributions to the field of surgery are well known and range from numerous clinical advances to pioneering scholarship and professional activities. Dr. Gross was ceaselessly ambitious and even remarked in his autobiography that his ‘‘conviction has always been that is far better for a man to wear out than to rust out.’’1 It is through this frame of motivation that Dr. Gross lived his life
A standardized comparison of peri-operative complications after minimally invasive esophagectomy: Ivor Lewis versus McKeown.
BACKGROUND: While our institutional approach to esophageal resection for cancer has traditionally favored a minimally invasive (MI) 3-hole, McKeown esophagectomy (MIE 3-hole) during the last five years several factors has determined a shift in our practice with an increasing number of minimally invasive Ivor Lewis (MIE IL) resections being performed. We compared peri-operative outcomes of the two procedures, hypothesizing that MIE IL would be less morbid in the peri-operative setting compared to MIE 3-hole.
METHODS: Our institution\u27s IRB-approved esophageal database was queried to identify all patients who underwent totally MI esophagectomy (MIE IL vs. MIE 3-hole) from June 2011 to May 2016. Patient demographics, preoperative and peri-operative data, as well as post-operative complications were compared between the two groups. Post-operative complications were analyzed using the Clavien-Dindo classification system.
RESULTS: There were 110 patients who underwent totally MI esophagectomy (MIE IL n = 49 [45%], MIE 3-hole n = 61 [55%]). The majority of patients were men (n = 91, 83%) with a median age of 62.5 (range 31-83). Preoperative risk stratifiers such as ECOG score, ASA, and Charlson Comorbidity Index were not significantly different between groups. Anastomotic leak rate was 2.0% in the MIE IL group compared to 6.6% in the MIE 3-hole group (p = 0.379). The rate of serious (Clavien-Dindo 3, 4, or 5) post-operative complications was significantly less in the MIE IL group (34.7 vs. 59.0%, p = 0.013). Serious pulmonary complications were not significantly different (16.3 vs. 26.2%, p = 0.251) between the two groups.
CONCLUSIONS: In this cohort, totally MIE IL showed significantly less severe peri-operative morbidity than MIE 3-hole, but similar rates of serious pulmonary complications and anastomotic leaks. These findings confirm the safety of minimally invasive Ivor Lewis esophagectomies for esophageal cancer when oncologically and clinically appropriate. Minimally invasive McKeown esophagectomy remains a satisfactory and appropriate option when clinically indicated
- …