State and local taxation

State and local taxation comprises those taxes that are collected at the sub-federal government levels in order to finance state and local public services, assigning discretion in the determination of rates and bases of these taxes to sub-federal governments. Consider a nation with different layers of government that are only serving administrative purposes. Each government level only distributes the public services to and collects the taxes from that nation’s citizens upon which they agreed at the national level. In such a country, no state or local taxation is necessary since the level of public goods and services is uniformly decided upon for the whole country. This leaves citizens in some local jurisdictions, which prefer more public services than the national average, as much dissatisfied as citizens in local jurisdictions, which prefer less. It is possible to provide public services, the benefits of which are geographically limited and which are not national in scope, at different levels in different sub-federal jurisdictions. Enabling citizens to consume publicly provided goods and services at different levels according to their preferences makes everyone better off without making someone worse off. In order to let people, who want to consume more, pay a higher tax price for those state and local services, taxes must be differentiated accordingly between states and local jurisdictions. In such a world with a differentiated supply of publicly provided goods, each individual can reside in a jurisdiction where a certain level of public services is provided to adequate tax prices. The art of state and local taxation is the assignment of different kinds of taxes to government levels such that an invisible hand properly guides a nation in an ideal world to an optimal multi-unit fiscal system. This is not necessarily the case in the real world and some answers exist why fiscal systems are not optimal.

Comparative Study of Impedance Eduction Methods

The absorption efficiency of acoustic liners used in aircraft engines is characterized by the acoustic impedance. World wide, many grazing ow test rigs and eduction methods are available that provide values for that impedance. However, a direct comparison and assessment of the data of the di erent rigs and methods is often not possible because test objects and test conditions are quite di erent. Only a few papers provide a direct comparison. Therefore, this paper together with a companion paper, present data measured with a reference test object under similar conditions in the DLR and NASA grazing ow test rigs. Additionally, by applying the in-house methods Liner Impedance Non-Uniform ow Solving algorithm (LINUS, DLR) and Convected Helmhholtz Equation approach (CHE, NASA) on the data sets, similarities and differences due to underlying theory are identi ed and discussed

A Review of Predictive and Prescriptive Offshore Wind Farm Operation and Maintenance

Offshore wind farms are a rapidly developing source of clean, low-carbon energy and as they continue to grow in scale and capacity, so does the requirement for their efficient and optimised operation and maintenance. Historically, approaches to maintenance have been purely reactive. However, there is a movement in offshore wind, and wider industry in general, towards more proactive, condition-based maintenance approaches which rely on operational data-driven decision making. This paper reviews the current efforts in proactive maintenance strategies, both predictive and prescriptive, of which the latter is an evolution of the former. Both use operational data to determine whether a turbine component will fail in order to provide sufficient warning to carry out necessary maintenance. Prescriptive strategies also provide optimised maintenance actions, incorporating predictions into a wider maintenance plan to address predicted failure modes. Beginning with a summary of common techniques used across both strategies, this review moves on to discuss their respective applications in offshore wind operation and maintenance. This review concludes with suggested areas for future work, underlining the need for models which can be simply incorporated by site operators and integrate live data whilst handling uncertainties. A need for further focus on medium-term planning strategies is also highlighted along with consideration of the question of how to quantify the impact of a proactive maintenance strategy

Design and Evaluation of a Zero Mass Flow Liner

In this study, the concept of a Zero Mass Flow Liner is evaluated. The concept enables impedance control by the induction of periodic bias flow through the perforated facing sheet of the liner. The periodic bias flow is generated by a secondary high amplitude acoustic actuation. By means of the periodic bias flow, the liner can be tuned to different operating points in a given range of grazing flow velocities. The equivalent fluid impedance model for perforated plates is modified to account for the effects of periodic bias flow and grazing flow. An optimization routine, based on a genetic algorithm, is implemented. The method is applicable to any liner concept and uses the impedance of the lined surface as boundary condition in a numerical simulation. Thereby, a set of liner parameters is derived in order to obtain the desired damping characteristics. Based on the results of the optimization, a Zero Mass Flow Liner is manufactured and consequently evaluated experimentally. The damping characteristics are evaluated in form of the dissipated energy along the lined surface. Prediction and measurements show agreement. The Zero Mass Flow Liner delivers broad band dissipation of high peak value over a range of grazing flow Mach numbers. Under grazing flow conditions, the effect of periodic bias flow is reduced. This poses high energy requirements in high Mach number flow regimes which might restrict the applicability of the Zero Mass Flow concept to grazing flows of low Mach numbers

Reduction of inertial end correction of perforated plates due to secondary high amplitude stimuli

The decrease in reactance of perforated plates at high sound pressure amplitudes is of interest for the design of Helmholtz resonator liners. It is associated with the loss of end correction due to flow separation at the orifices. In practical applications, complex acoustic signals impinge on perforations. The loss of end correction due to multiple stimuli of unrelated frequency and phase has not been considered yet. This study assesses and presents an empirical approximation for the reduction of end correction of perforated plates at primary frequencies when flow separation is induced by an additional secondary unrelated high amplitude stimulus

Dissipationseigenschaften periodisch durchströmter Liner bei streifendem Schalleinfall

Perforierte Wandauskleidungen mit Kavität, auch Liner genannt, stellen eine wichtige Schallreduktionstechnologie in durchströmten Kanälen wie beispielsweise Flugzeugtriebwerken dar. Bei modernen, emissionsarmen Triebwerken sind die zu dämpfenden Frequenzbestandteile eher tieffrequent und breitbandig auf einen größeren Frequenzbereich verteilt. Hierfür benötigen konventionelle, auf dem Resonatorprinzip basierende Linerkonzepte einen deutlich größeren Bauraum, der in Triebwerken zumeist nicht verfügbar ist. Daher besteht Bedarf an neuartigen Systemen mit breitbandiger Dämpfung. Vor diesem Hintergrund wird in dieser Arbeit das Wirkungsprinzip des sogenannten Zero-MassFlow-Liners (ZML) genauer untersucht. Das Dissipationsverhalten wird durch eine periodische Durchströmung der perforierten Wand erweitert. Für die zusätzliche Dissipation werden Wirbelbildung und -ablösung an den Löchern der perforierten Wand, ähnlich wie bei konstant durchströmten, sogenannten Bias-Flow-Linern (BFL), verantwortlich gemacht. Der Vorteil dieses Konzeptes ist, dass gegenüber dem BFL keine zusätzliche Luftversorgung benötigt wird. Im Labor kann eine periodische Durchströmung beispielsweise mit einem Lautsprecher hergestellt werden. In dieser Studie wird das Dissipationsverhalten periodisch durchströmter Liner in Abhängigkeit von der Schallschnelle in den Löchern und der Anregungsfrequenz untersucht. Die Ergebnisse zeigen für verschiedene Wandauskleidungen, dass das Dissipationsverhalten mit steigender Schallschnelle einen breitbandigeren Verlauf annimmt und die Anregungsfrequenz einen vergleichsweise geringen Einfluss hat

The Shelhigh No-React® bovine internal mammary artery: a questionable alternative conduit in coronary bypass surgery?

Background: Increasing age and comorbidities among patients undergoing coronary artery bypass surgery (CABG) stimulates the exhaustive research for alternative grafts. No-React® treatment should render the tissue resistant against degeneration and reduce early inflammatory response. The aim of the present study was an invasive assessment of the patency of No-React® bovine internal mammary artery (NRIMA grafts) used as bypass conduit in CABG surgery. Patients and methods: Nineteen NRIMA grafts were used in 17 patients (2.9%) out of a total of 572 patients undergoing CABG surgery within a 12-month period. All intraoperative data were assessed and in-hospital outcome was analysed. Follow-up examination was performed 7.0±4.0 months after initial surgery, including clinical status and coronary angiography to assess patency of the NRIMA grafts. Results: Average perioperative flow of all NRIMA grafts was 71±60ml/min. One patient died in hospital due to a multi-organ failure. Four patients refused invasive assessment. Follow-up was complete in 12 patients with overall 13 NRIMA grafts. Nine NRIMA grafts (69.2%) were used for the right coronary system, two NRIMA grafts (15.4%) on the LAD and two on the circumflex artery. Graft patency was 23.1% and was independent of the intraoperative flow measurement. Conclusions: NRIMA grafts show a very low patency and cannot be recommended as coronary bypass graft conduits. Patency was independent of the perioperative flow, assessed by Doppler ultrasound. Because of this unsatisfying observation, this type of graft should be utilised as a last resource conduit and used only to revascularise less important target vessels, such as the end branches of the right coronary arter

Temporary neurological dysfunction after surgery of the thoracic aorta: a predictor of poor outcome and impaired quality of life

Background: Transient neurological dysfunction (TND) consists of postoperative confusion, delirium and agitation. It is underestimated after surgery on the thoracic aorta and its influence on long-term quality of life (QoL) has not yet been studied. This study aimed to assess the influence of TND on short- and long-term outcome following surgery of the ascending aorta and proximal arch. Methods: Nine hundred and seven patients undergoing surgery of the ascending aorta and the proximal aortic arch at our institution were included. Two hundred and ninety patients (31.9%) underwent surgery because of acute aortic dissection type A (AADA) and 617 patients because of aortic aneurysm. In 547 patients (60.3%) the distal anastomosis was performed using deep hypothermic circulatory arrest (DHCA). TND was defined as a Glasgow coma scale (GCS) value <13. All surviving patients had a clinical follow up and QoL was assessed with an SF-36 questionnaire. Results: Overall in-hospital mortality was 8.3%. TND occurred in 89 patients (9.8%). As compared to patients without TND, those who suffered from TND were older (66.4 vs 59.9 years, p<0.01) underwent more frequently emergent procedures (53% vs 32%, p<0.05) and surgery under DHCA (84.3% vs 57.7%, p<0.05). However, duration of DHCA and extent of surgery did not influence the incidence of TND. In-hospital mortality in the group of patients with TND compared to the group without TND was similar (12.0% vs 11.4%; p=ns). Patients with TND suffered more frequently from coronary artery disease (28% vs 20.8%, p=ns) and were more frequently admitted in a compromised haemodynamic condition (23.6% vs 9.9%, p<0.05). Postoperative course revealed more pulmonary complications such as prolonged mechanical ventilation. Additional to their transient neurological dysfunction, significantly more patients had strokes with permanent neurological loss of function (14.6% vs 4.8%, p<0.05) compared to the patients without TND. ICU and hospital stay were significantly prolonged in TND patients (18±13 days vs 12±7 days, p<0.05). Over a mean follow-up interval of 27±14 months, patients with TND showed a significantly impaired QoL. Conclusion: The neurological outcome following surgery of the ascending aorta and proximal aortic arch is of paramount importance. The impact of TND on short- and long-term outcome is underestimated and negatively affects the short- and long-term outcom

Single fibre cytoarchitecture in ventilator-induced diaphragm dysfunction (VIDD) assessed by quantitative morphometry second harmonic generation imaging: Positive effects of BGP-15 chaperone co-inducer and VBP-15 dissociative corticosteroid treatment

Ventilator-induced diaphragm dysfunction (VIDD) is a common sequela of intensive care unit (ICU) treatment requiring mechanical ventilation (MV) and neuromuscular blockade (NMBA). It is characterised by diaphragm weakness, prolonged respirator weaning and adverse outcomes. Dissociative glucocorticoids (e.g., vamorolone, VBP-15) and chaperone co-inducers (e.g., BGP-15) previously showed positive effects in an ICU-rat model. In limb muscle critical illness myopathy, preferential myosin loss prevails, while myofibrillar protein post-translational modifications are more dominant in VIDD. It is not known whether the marked decline in specific force (force normalised to cross-sectional area) is a pure consequence of altered contractility signaling or whether diaphragm weakness also has a structural correlate through sterical remodeling of myofibrillar cytoarchitecture, how quickly it develops, and to which extent VBP-15 or BGP-15 may specifically recover myofibrillar geometry. To address these questions, we performed label-free multiphoton Second Harmonic Generation (SHG) imaging followed by quantitative morphometry in single diaphragm muscle fibres from healthy rats subjected to five or 10 days of MV + NMBA to simulate ICU treatment without underlying confounding pathology (like sepsis). Rats received daily treatment of either Prednisolone, VBP-15, BGP-15 or none. Myosin-II SHG signal intensities, fibre diameters (FD) as well as the parameters of myofibrillar angular parallelism (cosine angle sum, CAS) and in-register of adjacent myofibrils (Vernier density, VD) were computed from SHG images. ICU treatment caused a decline in FD at day 10 as well as a significant decline in CAS and VD from day 5. Vamorolone effectively recovered FD at day 10, while BGP-15 was more effective at day 5. BGP-15 was more effective than VBP-15 in recovering CAS at day 10 although not to control levels. In-register VD levels were restored at day 10 by both compounds. Our study is the first to provide quantitative insights into VIDD-related myofibrillar remodeling unravelled by SHG imaging, suggesting that both VBP-15 and BGP-15 can effectively ameliorate the structure-related dysfunction in VIDD

Does rating the operation videos with a checklist score improve the effect of E-learning for bariatric surgical training? Study protocol for a randomized controlled trial

Background: Laparoscopic training has become an important part of surgical education. Laparoscopic Roux-en-Y gastric bypass (RYGB) is the most common bariatric procedure performed. Surgeons must be well trained prior to operating on a patient. Multimodality training is vital for bariatric surgery. E-learning with videos is a standard approach for training. The present study investigates whether scoring the operation videos with performance checklists improves learning effects and transfer to a simulated operation. Methods/design: This is a monocentric, two-arm, randomized controlled trial. The trainees are medical students from the University of Heidelberg in their clinical years with no prior laparoscopic experience. After a laparoscopic basic virtual reality (VR) training, 80 students are randomized into one of two arms in a 1:1 ratio to the checklist group (group A) and control group without a checklist (group B). After all students are given an introduction of the training center, VR trainer and laparoscopic instruments, they start with E-learning while watching explanations and videos of RYGB. Only group A will perform ratings with a modified Bariatric Objective Structured Assessment of Technical Skill (BOSATS) scale checklist for all videos watched. Group B watches the same videos without rating. Both groups will then perform an RYGB in the VR trainer as a primary endpoint and small bowel suturing as an additional test in the box trainer for evaluation. Discussion: This study aims to assess if E-learning and rating bariatric surgical videos with a modified BOSATS checklist will improve the learning curve for medical students in an RYGB VR performance. This study may help in future laparoscopic and bariatric training courses. Trial registration: German Clinical Trials Register, DRKS00010493. Registered on 20 May 2016