Bernstein-Gelfand-Gelfand sequences

This paper is devoted to the study of geometric structures modeled on homogeneous spaces G/P, where G is a real or complex semisimple Lie group and $P\subset G$ is a parabolic subgroup. We use methods from differential geometry and very elementary finite-dimensional representation theory to construct sequences of invariant differential operators for such geometries, both in the smooth and the holomorphic category. For G simple, these sequences specialize on the homogeneous model G/P to the celebrated (generalized) Bernstein-Gelfand-Gelfand resolutions in the holomorphic category, while in the smooth category we get smooth analogs of these resolutions. In the case of geometries locally isomorphic to the homogeneous model, we still get resolutions, whose cohomology is explicitly related to a twisted de Rham cohomology. In the general (curved) case we get distinguished curved analogs of all the invariant differential operators occurring in Bernstein-Gelfand-Gelfand resolutions (and their smooth analogs). On the way to these results, a significant part of the general theory of geometrical structures of the type described above is presented here for the first time.Comment: 45 page

Inter-organizational network management in an innovation context:combining ego and whole network perspective

Although there is growing interest into the research field of inter-organizational innovation networks, few attempts have been made to develop systematic methods for the active management of such networks. This is especially true for approaches combining the view of single actors and the network as a whole. In response to this gap, this research presents a new method for the management of inter-organizational networks that can help to increase innovation outcome. The introduced approach accomplishes two goals. Firstly, it provides guidance for the measurement of the current collaboration status of a network, its optimal future collaboration status and the gap between them. Secondly, it provides systematics for the development of clear network management strategies for each network actor for closing this collaboration gap. As a result, better exploitation of existing collaboration potential is expected to increase innovation output. The method builds upon work by Kohl et al. (2015) who approached network management on a whole network level providing a solution for the management of entire networks and Ojasalo (2004) who suggested a network management method taking the perspective of a single network actor on the so called ego level. The novelty value of the presented method lies in the demonstration of how these different levels of network management can be combined. The two levels of analysis are linked through reliance on the same data set. The developed method is demonstrated through a case study. The analysis builds upon a questionnaire asking network actors for an estimation of the current collaboration status and a future collaboration potential amongst them. Social network analysis software was used to calculate network measures such as the level of density and to visualize the network graphically. As a result customized strategies for improving collaboration within the investigated network are presented

Wpływ zapalenia tarczycy Hashimoto, stężenia TSH oraz dodatniego wyniku obecności przeciwciał przeciwtarczycowych na występowanie zróżnicowanego raka tarczycy

  Introduction: The relationship between Hashimoto’s thyroiditis (HT) and thyroid cancer (TC) is controversial. While most surgical studies report a high incidence of malignancy among patients with HT, cytological studies do not. The role of autoantibodies in the incidence of malignancy is unclear. Material and methods: A single-centre retrospective observational study was conducted in patients evaluated for thyroid nodules by US-guided fine-needle aspiration cytology (FNAC) and, if indicated, by surgery. The levels of thyroid-stimulating hormone (TSH) and anti-thyroid antibodies were measured at the time of FNAC. Results: Of 4947 patients, 599 (12.1%) were diagnosed with HT. A malignant/suspicious cytological result was found in 14.2% of the patients with HT and in 15.2% of the others. The odds ratio (OR) for malignancy in HT was 0.921 (0.716–1.183, p = 0.51). Of 1603 patients who underwent surgery, differentiated thyroid carcinoma was found in 29.5% of the HT patients and in 15.2% of the others (OR 2.33, 95% confidence interval CI, 1.403–3.854, p < 0,001). Low TSH (< 0.4 mIU/L) decreased the malignancy rate in the entire patient population, both when considering the cytological results and the surgical results. This was not confirmed in the subgroup diagnosed with HT. No relationship was observed between autoantibodies against thyroid peroxidase (ATP) or thyroglobulin (ATG) and malignancy rate. Conclusions: No association between HT and thyroid cancer was observed cytologically; a positive relationship in histological series was caused by selection bias. Low TSH levels decreased the risk of TC in patients with nodular goitre, but this has not been proven in patients with HT. (Endokrynol Pol 2016; 67 (1): 48–53)    Wstęp: Związek pomiędzy zapaleniem tarczycy Hashimoto (HT) i rakiem tarczycy (TC) jest uważany za kontrowersyjny. Podczas gdy większość badań nad operacjami dokumentuje wysoką częstotliwość występowania guzów wśród pacjentów z HT, badania cytologiczne tego nie potwierdzają. Rola autoprzeciwciał w częstotliwości występowania guzów nie jest do końca jasna. Materiał i metody: Wśród pacjentów, u których stwierdzono guzki tarczycy przeprowadzono jednoośrodkowe, retrospektywne badanie obserwacyjne poprzez aspiracyjną cytologię cienkoigłową (FNAC) pod kontrolą USG oraz operacyjnie, jeśli takie było wskazanie. Stężenia tyreotropiny (TSH) oraz przeciwciał przeciwtarczycowych zmierzono podczas przeprowadzania FNAC. Wyniki: Z 4947 pacjentów, u 599 (12,1%) zdiagnozowano HT. Zły/podejrzany wynik cytologii stwierdzono u 14,2% pacjentów z HT oraz u 15,2% innych pacjentów. Iloraz szans (OR) dla guza przy HT wynosił 0,921 (0,716–1,183, p = 0,51). Z 1603 pacjentów, których poddano operacji, zróżnicowanego raka tarczycy wykryto u 29,5% pacjentów z HT i u 15,2% innych pacjentów (OR 2,33; 95% CI; 1,403–3,854, p < 0,001). Niski poziom TSH (< 0,4 mIU/l) obniża wskaźnik występowania guza w całej populacji pacjentów, zarówno gdy bierze się pod uwagę wyniki cytologiczne, jak i operacyjne. Nie zostało to potwierdzone w podgrupie, u której zdiagnozowano HT. Nie zaobserwowano związku pomiędzy autoprzeciwciałami przeciw peroksydazie tarczycowej (ATP) lub tyreoglobulinie (ATG) i wskaźnikiem występowania guzów. Wnioski: Nie zaobserwowano cytologicznego związku pomiędzy HT i rakiem tarczycy; dodatni związek w seriach histologicznych spowodowany był stronniczością selekcji. Niskie stężenie TSH obniżył ryzyko TC u pacjentów z wolem guzkowym, lecz nie zostało to udowodnione u pacjentów z HT. (Endokrynol Pol 2016; 67 (1): 48–53)

Adrenal Venous Sampling: Where Is the Aldosterone Disappearing to?

Adrenal venous sampling (AVS) is generally considered to be the gold standard in distinguishing unilateral and bilateral aldosterone hypersecretion in primary hyperaldosteronism. However, during AVS, we noticed a considerable variability in aldosterone concentrations among samples thought to have come from the right adrenal glands. Some aldosterone concentrations in these samples were even lower than in samples from the inferior vena cava. We hypothesized that the samples with low aldosterone levels were unintentionally taken not from the right adrenal gland, but from hepatic veins. Therefore, we sought to analyze the impact of unintentional cannulation of hepatic veins on AVS. Thirty consecutive patients referred for AVS were enrolled. Hepatic vein sampling was implemented in our standardized AVS protocol. The data were collected and analyzed prospectively. AVS was successful in 27 patients (90%), and hepatic vein cannulation was successful in all procedures performed. Cortisol concentrations were not significantly different between the hepatic vein and inferior vena cava samples, but aldosterone concentrations from hepatic venous blood (median, 17 pmol/l; range, 40–860 pmol/l) were markedly lower than in samples from the inferior vena cava (median, 860 pmol/l; range, 460–4510 pmol/l). The observed difference was statistically significant (P < 0.001). Aldosterone concentrations in the hepatic veins are significantly lower than in venous blood taken from the inferior vena cava. This finding is important for AVS because hepatic veins can easily be mistaken for adrenal veins as a result of their close anatomic proximity

Perinatal health monitoring through a European lens: eight lessons from the Euro-Peristat report on 2015 births

International audienceNo abstract availabl