The role of inter-institutional cooperation in surgical training and practice: A German-Tanzanian model

Objective: To highlight the feasibility and importance of inter-institutional cooperation, particularly between countries of the north and south, in improving and maintaining standards in medical training and practice.Setting and sources: A four-year academic exchange program was set up between the departments of Surgery at Muhimbili University College of Health Sciences, Dar es Salaam, Tanzania, and the Mannheim Faculty of Medicine of Heidelberg University, Germany.Methods: Contact was first initiated between the heads of department at the two institutions and communications was almost entirely through e-mail. A Memorandum of Understanding between the two institutions was prepared and signed. The program was sponsored by the German Academic Exchange Service (DAAD), and involved exchange of teaching material, diagnostic equipment and 30 students, residents and surgical teachers between the two institutions over the 4 year period. A number of research projects were also initiated between the two departments.Conclusion: Academic Exchange programs between institutions in developed and developing countries can provide badly needed technical cooperation and valuable experiences for students and staff from both sides of North-South divide in addition to forging lasting professional and personal relationships between those taking part in the exchange programs.Keywords: Surgical training, North-South divide, academic exchange programs, Tanzania, German

In-medium Hadrons - Properties, Interaction and Formation

In this talk various aspects of in-medium behavior of hadrons are discussed with an emphasis on observable effects. Examples for theoretical predictions of in-medium spectral functions are given and the importance of resonance-hole excitations is stressed. It is also stressed that final state interactions can have a major effect on observables and thus have to be considered as part of the theory. This is demonstrated with examples from neutrino-nucleus interactions. Finally, the possibility to access hadron formation times in high-energy photonuclear (or neutrino-induced) reactions is illustrated.Comment: Invited talk given by U. Mosel at Vth Conference on Hadronic Physics, ICTP, Trieste, May 200

IMPLEMENTIERUNG EINES INTERACTIVE-PRICERESPONSE- SYSTEMS BEI EINER LOW-COST-AIRLINE

Das Wettbewerbsumfeld in der Airline-Branche hat sich in den letzten Jahren mit zunehmenden Marktanteilen der Low-Cost-Airlines grundlegend verändert. Zwar hat die Airline-Branche mittlerweile eine Marktbereinigung erfahren, aber nach wie vor verstärken Low-Cost-Airlines den Preiswettbewerb. Durch eine zunehmende Preistransparenz in der Branche wird es für Fluggesellschaften immer schwieriger unterschiedliche Kundensegmente mit differenzierten Preisen zu bedienen. Die Gefahr besteht, dass Kunden zu niedrigeren Preisen als ihren tatsächlichen Zahlungsbereitschaften kaufen und den Fluggesellschaften Deckungsbeitragseinbußen entstehen. Aus diesem Grund sind Preismechanismen, die eine individualisierte und weniger transparente Preissetzung ermöglichen, für Fluggesellschaften besonders interessant. Der vorliegende Beitrag stellt die Funktionsweise eines interaktiven Preismechanismus dar, bei dem Kunden anhand ihrer Flexibilität den Preis mitbestimmen und Fluggesellschaften dadurch individualisierte Preise erzielen können. In einer empirischen Studie bei einer Low-Cost-Airline wird gezeigt, wie ein Interactive-Price- Response-Mechanismus (IPRS) in das bestehende Buchungs- und Preissystem einer Fluggesellschaft als service-orientierte Lösung implementiert werden kann

Weighted finite energy sum rules for the omega meson in nuclear matter

The possible in-medium changes of the properties of an omega meson placed in cold nuclear matter are constrained by QCD sum rules. It is shown that the sum rules cannot fully determine the in-medium spectral shape of the omega meson. However, for a given parameterization the sum rules can constrain or correlate the hadronic parameters. It is shown that weighted finite energy sum rules provide a proper framework to study directly these constraints/correlations. Two typical parameterizations of possible in-medium omega spectra are analyzed, namely (i) a one-peak structure with arbitrary position and width of the peak and (ii) a structure with two (narrow) peaks, caused by the genuine omega meson and a resonance-hole branch. The sum rules provide for case (i) a mass-width correlation and for case (ii) a correlation between the peak heights and the peak position of the omega branch. It is also analyzed how the obtained results depend on the size of the relevant four-quark operator evaluated with respect to a nucleon. Finally it is argued that a strict vector meson dominance scenario is not compatible with the sum rules.Comment: 14 page

QCD sum rules at finite density in the large-N_c limit: The coupling of the rho-nucleon system to the D_{13}(1520)

QCD sum rules are studied for the vector-isovector current at finite baryon density in the limit of large number of colors N_c. For the condensate side it is shown that in this limit the four-quark condensate factorizes also for the finite density case. At the hadronic side the medium dependence is expressed in terms of the current-nucleon forward scattering amplitude. Generalizing vector meson dominance we allow for a direct coupling of the current to the nucleon as well as a coupling via the rho meson. We discuss the N_c dependence of (a) modifications of the pion cloud of the rho meson, (b) mixing with other mesons (in particular a_1 and omega) and (c) resonance-hole excitations R N^{-1}. We show that only the last effect survives in the large-N_c limit. Saturating the sum rules with a simple hadronic ansatz which allows for the excitation of the D_{13}(1520) we determine the coupling of the latter to the rho-nucleon and the photon-nucleon system. These couplings are hard to determine from vacuum physics alone.Comment: 13 pages, 2 figure

CoCStom trial: study protocol for a randomised trial comparing completeness of adjuvant chemotherapy after early versus late diverting stoma closure in low anterior resection for rectal cancer

Background: Current evidence supports a diverting stoma in patients undergoing low anterior resection with total mesorectal excision for rectal cancer as it reduces clinical severity of anastomotic leakage. However, relevant stoma morbidity after rectal cancer surgery exists and has a significant impact on quality of life. Moreover, a diverting stoma has an influence on completeness of chemotherapy but it remains unclear in which way. There is no evidence regarding optimal timing for stoma closure in relation to adjuvant chemotherapy. Two randomised controlled trials have studied early stoma closure after low anterior resection in patients with rectal cancer, one of them showing that early closure around day 8 after resection is possible without increasing morbidity. Methods/Design: CoCStom is a randomised multicentre trial comparing completeness of adjuvant chemotherapy as primary endpoint after early (8–10 days after resection, before starting adjuvant therapy) versus late (~26 weeks after resection and completion of adjuvant therapy) stoma closure in patients with locally advanced rectal cancer undergoing low anterior resection after neoadjuvant therapy. After exclusion of post-operative anastomotic leakage 257 patients from 30 German hospitals are planned to be included in order to assure a power of 80 % for the confirmatory analysis of at least 214 evaluable cases. An absolute increase of 20 % for the rate of completely administered adjuvant chemotherapy is regarded as a clinically meaningful step forward and serves as basis for sample size calculation. Quality of life, stoma-related complications, individual completeness of chemotherapy rate, percentage of patients stopping adjuvant therapy or undergoing dose modifications or delay, oncological outcomes, cumulative days of hospitalisation and number of readmissions, rate of symptomatic anastomotic leaks after stoma closure, mortality, post-operative complications and toxicity of adjuvant chemotherapy are secondary endpoints. Discussion: The CoCStom trial aims to clarify optimal timing of stoma closure in the context of adjuvant chemotherapy. Depending on the results of the trial, patients could benefit either from early or late stoma closure in regard to long term oncological survival due to a higher rate of completeness of adjuvant chemotherapy treatment and thus better effectiveness. Trial registration: German Clinical Trials Register, DRKS00005113 . Registered 28 August 201

Complete Relativistic Description of the N*(1520)

A relativistic description of spin 3/2 resonances and their decay channels is presented by calculating their selfenergies and spectral functions. The full vector-spinor structure is taken into account. Special emphasis is put on the N*(1520) and its decay channels pi N, rho N and pi \Delta. All interactions are formulated such that only the correct number of degrees of freedom of a spin 3/2 state is propagated. The obtained results are compared with several approximations frequently used to avoid the complicated vector-spinor structure. Since this structure is taken fully into account here, the quality of the approximations can be judged.Comment: 32 pages, 40 figure

High genetic diversity among Mycobacterium tuberculosis complex strains from Sierra Leone

<p>Abstract</p> <p>Background</p> <p>Among tuberculosis (TB) high incidence regions, Sub-Saharan Africa is particularly affected with approx. 1.6 million new cases every year. Besides this dramatic situation, data on the diversity of <it>Mycobacterium tuberculosis </it>complex (MTBC) strains causing this epidemic in this area are only sparsely available. Here we analyzed the population structure of strains from Sierra Leone with a special focus on the prevalence of <it>M. africanum</it>.</p> <p>Results</p> <p>A total of 97 strains isolated from smear positive cases registered for re-treatment in the Western Area and Kenema districts in years 2003/2004 were investigated by susceptibility testing (first line drugs) and molecular typing (IS<it>6110 </it>fingerprinting, spoligotyping, and MIRU-VNTR typing).</p> <p>Among the strains analyzed, 32 were resistant to isoniazid, and 11 were multidrug resistant (at least resistant to isoniazid and rifampin). The population diversity was high with two previously described <it>M. africanum </it>lineages (West African-1, n = 6; West African-2, n = 17) and seven <it>M. tuberculosis </it>lineages (Haarlem, n = 14; LAM, n = 15; EAI, n = 4; Beijing, n = 4; S-type, n = 4, X-type, n = 1; Cameroon, n = 4). Furthermore, two new <it>M. tuberculosis </it>genotypes Sierra Leone-1 (n = 7) and -2 (n = 10) were found. Strain classification according to a 7 bp deletion in pks1/15 revealed that the majority of <it>M. tuberculosis </it>strains belonged to the Euro American lineage (66 out of 74).</p> <p>Conclusion</p> <p>Resistance rates in Sierra Leone have reached an alarming level. The population structure of MTBC strains shows an intriguing diversity raising the question of possible consequences for TB epidemic and for the introduction of new diagnostic tests or treatment strategies in West Africa.</p