Inlet Channel for a Ducted Fan Propulsion System of a Light Aircraft

So-called "cold-jet" propulsion units consist of a piston engine, a blower and the necessary air duct. Till now, all attempts to utilize "cold-jet" propulsion units to maintain the thrust of an airplane have been unsuccessful. Analysis has shown that the main difficulty is the deformation of the flow field at the entry to the blower [1]

Convex optimization problem prototyping for image reconstruction in computed tomography with the Chambolle-Pock algorithm

The primal-dual optimization algorithm developed in Chambolle and Pock (CP), 2011 is applied to various convex optimization problems of interest in computed tomography (CT) image reconstruction. This algorithm allows for rapid prototyping of optimization problems for the purpose of designing iterative image reconstruction algorithms for CT. The primal-dual algorithm is briefly summarized in the article, and its potential for prototyping is demonstrated by explicitly deriving CP algorithm instances for many optimization problems relevant to CT. An example application modeling breast CT with low-intensity X-ray illumination is presented.Comment: Resubmitted to Physics in Medicine and Biology. Text has been modified according to referee comments, and typos in the equations have been correcte

Application of Photogrammetry in Biomedical Science

Peer reviewedPostprin

Trade blocs and trade wars during the interwar period

What precisely were the causes and consequences of the trade wars in the 1930s? Were there perhaps deeper forces at work in reorienting global trade prior to the outbreak of World War II? And what lessons may this particular historical episode provide for the present day? To answer these questions, we distinguish between long‐run secular trends in the period from 1920 to 1939 related to the formation of trade blocs and short‐run disruptions associated with the trade wars of the 1930s. We argue that the trade wars mainly served to intensify pre‐existing efforts toward the formation of trade blocs which dated from at least 1920. More speculatively, we argue that the trade wars of the present day may serve a similar purpose as those in the 1930s, that is, the intensification of China‐ and US‐centric trade blocs

Development of classification criteria for hand osteoarthritis: comparative analyses of persons with and without hand osteoarthritis

Objectives Further knowledge about typical hand osteoarthritis (OA) characteristics is needed for the development of new classification criteria for hand OA.Methods In a cross-sectional multi-centre international study, a convenience sample of patients from primary and secondary/tertiary care with a physician-based hand OA diagnosis (n = 128) were compared with controls with hand complaints due to inflammatory or non-inflammatory conditions (n = 70). We examined whether self-reported, clinical, radiographic and laboratory findings were associated with hand OA using logistic regression analyses. Discrimination between groups was assessed by calculating the area under receiver operating curves (AUC).Results Strong associations with hand OA were observed for radiographic osteophytes (OR = 1.62, 95% CI 1.40 to 1.88) and joint space narrowing (JSN) (OR = 1.57, 95% CI 1.36 to 1.82) in the distal interphalangeal (DIP) joints with excellent discrimination (AUC = 0.82 for both). For osteophytes and JSN, we found acceptable discrimination between groups in the proximal interphalangeal joints (AUC = 0.77 and 0.78, respectively), but poorer discrimination in the first carpometacarpal joints (AUC = 0.67 and 0.63, respectively). Painful DIP joints were associated with hand OA, but were less able to discriminate between groups (AUC = 0.67). Age and family history of OA were positively associated with hand OA, whereas negative associations were found for pain, stiffness and soft tissue swelling in metacarpophalangeal joints, pain and marginal erosions in wrists, longer morning stiffness, inflammatory biomarkers and autoantibodies.Conclusions Differences in symptoms, clinical findings, radiographic changes and laboratory tests were found in patients with hand OA versus controls. Radiographic OA features, especially in DIP joints, were best suited to discriminate between groups.Clinical epidemiolog

The Normative Problem of Merit Goods in Perspective

In his Theory of Public Finance (1959), Musgrave invented the concept of merit wants to describe public wants that are satisfied by goods provided by the government in violation of the principle of consumer sovereignty. Starting from Musgrave’s mature discussion (1987), I construct two categories to classify the explanations of merit goods. The first strand of thought attempts to justify merit goods within the New welfare economics, by modifying its assumptions to accommodate irrationality, uncertainty, lack of information, and psychic externalities. The second category encompasses more radical departures from consumer sovereignty, drawn from philosophical critiques of economics. In the third part of the paper, I argue that the two strands might be represented by a non-individualistic social welfare function. I also show how this solution echoes Musgrave’s early views on public expenditures before he coined the concept of merit wants. From an historical perspective, the survival of the concept highlights the persistence of a social point of view in welfare economics