Thermal Stability of RP-2 for Hydrocarbon Boost Regenerative Cooling

A series of tests were performed in the NASA Glenn Research Centers Heated Tube Facility to study the heat transfer and thermal stability behavior of RP-2 under conditions similar to those found in rocket engine cooling channels. It has long been known that hydrocarbon fuels, such as RP-2, can decompose at high temperature to form deposits (coke) which can adversely impact rocket engine cooling channel performance. The heated tube facility provides a simple means to study these effects. Using resistively heated copper tubes in a vacuum chamber, flowing RP-2 was heated to explore thermal effects at a range of test conditions. Wall temperature (850-1050F) and bulk fluid temperature (300-500F) were varied to define thermal decomposition and stability at each condition. Flow velocity and pressure were fixed at 75 fts and 1000 psia, respectively. Additionally, five different batches of RP-2 were tested at identical conditions to examine any thermal stability differences resulting from batch to batch compositional variation. Among these tests was one with a potential coke reducing additive known as 1,2,3,4-Tetrahydroquinoline (THQ). While copper tubes were used for the majority of tests, two exploratory tests were performed with a copper alloy known as GRCop-42. Each tube was instrumented with 15 thermocouples to examine the temperature profile, and carbon deposition at each thermocouple location was determined post-test in an oxidation furnace. In many tests, intermittent local temperature increases were observed visually and in the thermocouple data. These hot spots did not appear to correspond with a higher carbon deposition

On the Bitrate Adaptation of Shared Media Experience Services

In Shared Media Experience Services (SMESs), a group of people is interested in streaming consumption in a synchronised way, like in the case of cloud gaming, live streaming, and interactive social applications. However, group synchronisation comes at the expense of other Quality of Experience (QoE) factors due to both the dynamic and diverse network conditions that each group member experiences. Someone might wonder if there is a way to keep a group synchronised while maintaining the highest possible QoE for each one of its members. In this work, at first we create a Quality Assessment Framework capable of evaluating different SMESs improvement approaches with respect to traditional metrics like media bitrate quality, playback disruption, and end user desynchronisation. Secondly, we focus on the bitrate adaptation for improving the QoE of SMESs, as an incrementally deployable end user triggered approach, and we formulate the problem in the context of Adaptive Real Time Dynamic Programming (ARTDP). Finally, we develop and apply a simple QoE aware bitrate adaptation mechanism that we compare against youtube live-streaming traces to find that it improves the youtube performance by more than 30%

Connecting the Edges: A Universal, Mobile-Centric, and Opportunistic Communications Architecture

The Internet has crossed new frontiers with access to it getting faster and cheaper. Considering that the architectural foundations of today's Internet were laid more than three decades ago, the Internet has done remarkably well until today coping with the growing demand. However, the future Internet architecture is expected to support not only the ever growing number of users and devices, but also a diverse set of new applications and services. Departing from the traditional host-centric access paradigm, where access to a desired content is mapped to its location, an information-centric model enables the association of access to a desired content with the content itself, irrespective of the location where it is being held. UMOBILE tailors the information-centric communication model to meet the requirements of opportunistic communications, integrating those connectivity approaches into a single architecture. By pushing services near the edge of the network, such an architecture can pervasively operate in any networking environment and allows for the development of innovative applications, providing access to data independent of the level of end-to-end connectivity availability

ESPRAS Survey on Continuing Education in Plastic, Reconstructive and Aesthetic Surgery in Europe

Background Specialty training in plastic, reconstructive and aesthetic surgery is a prerequisite for safe and effective provision of care. The aim of this study was to assess and portray similarities and differences in the continuing education and specialization in plastic surgery in Europe. Material and Methods A detailed questionnaire was designed and distributed utilizing an online survey administration software. Questions addressed core items regarding continuing education and specialization in plastic surgery in Europe. Participants were addressed directly via the European Leadership Forum (ELF) of the European Society of Plastic, Reconstructive and Aesthetic Surgery (ESPRAS). All participants had detailed knowledge of the organization and management of plastic surgical training in their respective country. Results The survey was completed by 29 participants from 23 European countries. During specialization, plastic surgeons in Europe are trained in advanced tissue transfer and repair and aesthetic principles in all parts of the human body and within several subspecialties. Moreover, rotations in intensive as well as emergency care are compulsory in most European countries. Board certification is only provided for surgeons who have had multiple years of training regulated by a national board, who provide evidence of individually performed operative procedures in several anatomical regions and subspecialties, and who pass a final oral and/or written examination. Conclusion Board certified plastic surgeons meet the highest degree of qualification, are trained in all parts of the body and in the management of complications. The standard of continuing education and qualification of European plastic surgeons is high, providing an excellent level of plastic surgical care throughout Europe

Burnout syndrome among psychiatric trainees in 22 countries: Risk increased by long working hours, lack of supervision, and psychiatry not being first career choice

Background: Postgraduate medical trainees experience high rates of burnout, but evidence regarding psychiatric trainees is missing. We aim to determine burnout rates among psychiatric trainees, and identify individual, educational and work-related factors associated with severe burnout.  Methods: In an online survey psychiatric trainees from 22 countries were asked to complete the Maslach Burnout Inventory (MBI-GS) and provide information on individual, educational and work-related parameters. Linear mixed models were used to predict the MBI-GS scores, and a generalized linear mixed model to predict severe burnout.  Results: This is the largest study on burnout and training conditions among psychiatric trainees to date. Complete data were obtained from 1980 out of 7625 approached trainees (26%; range 17.8-65.6%). Participants were 31.9 (SD 5.3) years old with 2.8 (SD 1.9) years of training. Severe burnout was found in 726 (36.7%) trainees. The risk was higher for trainees who were younger (P < 0.001), without children (P = 0.010), and had not opted for psychiatry as a first career choice (P = 0.043). After adjustment for socio-demographic characteristics, years in training and country differences in burnout, severe burnout remained associated with long working hours (P < 0.001), lack of supervision (P < 0.001), and not having regular time to rest (P = 0.001). Main findings were replicated in a sensitivity analysis with countries with response rate above 50%.  Conclusions: Besides previously described risk factors such as working hours and younger age, this is the first evidence of negative influence of lack of supervision and not opting for psychiatry as a first career choice on trainees' burnout

Systemic therapy of Cushing’s syndrome

Cushing’s disease (CD) in a stricter sense derives from pathologic adrenocorticotropic hormone (ACTH) secretion usually triggered by micro- or macroadenoma of the pituitary gland. It is, thus, a form of secondary hypercortisolism. In contrast, Cushing’s syndrome (CS) describes the complexity of clinical consequences triggered by excessive cortisol blood levels over extended periods of time irrespective of their origin. CS is a rare disease according to the European orphan regulation affecting not more than 5/10,000 persons in Europe. CD most commonly affects adults aged 20–50 years with a marked female preponderance (1:5 ratio of male vs. female). Patient presentation and clinical symptoms substantially vary depending on duration and plasma levels of cortisol. In 80% of cases CS is ACTH-dependent and in 20% of cases it is ACTH-independent, respectively. Endogenous CS usually is a result of a pituitary tumor. Clinical manifestation of CS, apart from corticotropin-releasing hormone (CRH-), ACTH-, and cortisol-producing (malign and benign) tumors may also be by exogenous glucocorticoid intake. Diagnosis of hypercortisolism (irrespective of its origin) comprises the following: Complete blood count including serum electrolytes, blood sugar etc., urinary free cortisol (UFC) from 24 h-urine sampling and circadian profile of plasma cortisol, plasma ACTH, dehydroepiandrosterone, testosterone itself, and urine steroid profile, Low-Dose-Dexamethasone-Test, High-Dose-Dexamethasone-Test, after endocrine diagnostic tests: magnetic resonance imaging (MRI), ultra-sound, computer tomography (CT) and other localization diagnostics. First-line therapy is trans-sphenoidal surgery (TSS) of the pituitary adenoma (in case of ACTH-producing tumors). In patients not amenable for surgery radiotherapy remains an option. Pharmacological therapy applies when these two options are not amenable or refused. In cases when pharmacological therapy becomes necessary, Pasireotide should be used in first-line in CD. CS patients are at an overall 4-fold higher mortality rate than age- and gender-matched subjects in the general population. The following article describes the most prominent substances used for clinical management of CS and gives a systematic overview of safety profiles, pharmacokinetic (PK)-parameters, and regulatory framework

Rethinking stasis and utopianism: empty placards and imaginative boredom in the Greek crisis-scape

This chapter traces specific modalities for performing stasis and rethinking utopianism against the backdrop of the recent financial crisis in Greece and, generally, of conditions shaped within the totalizing order Mark Fisher has called “capitalist realism.” Boletsi probes the ways two works deal with the (im)possibility of resistance from within the neoliberal “now”: the short story “Placard and Broomstick” (Ikonomou) and an Athenian wall writing that translates as “I am bored imaginatively.” The empty placard that takes center stage in Ikonomou’s story and the imaginative boredom registered on the walls of Athens test different modalities of stasis against alienation, dispossession, and the contracting of the future. Boletsi argues that both works disengage from conceptions of subjectivity that rest on the binary of either a passive or an active subject—either an acquiescent victim or a revolutionary hero who challenges power from its outside. The story stages the desire for alternative languages by registering a crisis of representation and the inadequacy of existing narratives. The wall writing taps into the modality of the “middle voice” to reconfigure one of the symptoms of capitalist realism—the boredom of unemployment, consumerism, or an indebted life—into a potential resource for different modes of being that carry glimpses of utopianism. Both works, albeit differently, challenge neoliberal imperatives of acquiescence, normalization, or “moving forward.” Although they stage the limited possibilities for resistance within a totalizing system, they also enable alternative configurations of subjectivity, agency, and futurity.Modern and Contemporary Studie