Flow cytometric DNA ploidy analysis of ovarian granulosa cell tumors

Abstract The nuclear DNA content of 50 ovarian tumors initially diagnosed as granulosa cell tumors was measured by flow cytometry using paraffin-embedded archival material. The follow-up period of the patients ranged from 4 months to 19 years. Thirty-eight tumors were diploid or near-diploid, while 5 were aneuploid. DNA profiles of 7 tumors could not be evaluated. All 50 tumors were immunohistochemically tested for expression of intermediate filament proteins vimentin and cytokeratin and epithelial membrane antigen. The cells of all but 3 tumors expressed vimentin. These 3 vimentin-negative tumors were positive for cytokeratin and epithelial membrane antigen. They were highly aneuploid and though originally diagnosed as granulosa cell tumors, most likely represent undifferentiated carcinomas. Hence, only 2 typical granulosa cell tumors were aneuploid. In addition, frozen tissue samples from 9 of 10 granulosa cell tumors showed a DNA diploid content. Our results indicate that granulosa cell tumors tend to be diploid or have only minor ploidy abnormalities which is in line with their relatively benign character. An undifferentiated carcinoma should be considered in the differential diagnosis of tumors with a high DNA index

A tail of plumage colouration: disentangling geographic, seasonal and dietary effects on plumage colour in a migratory songbird

Plumage ornamentation in birds serves critical inter- and intra-sexual signaling functions. While carotenoid-based plumage colouration is often viewed as a classic condition-dependent sexually selected trait, plumage colouration can be influenced by a wide array of both intrinsic and extrinsic factors. Understanding the mechanisms underlying variation in colouration is especially important for species where the signaling function of ornamental traits is complex or when the literature is conflicting. Here, we examined variation in the yellow/orange tail feathers of American redstarts Setophaga ruticilla passing through two migratory stopover sites in eastern North America during both spring and fall migration to assess the role of geographic variation and seasonality in influencing feather colouration. In addition, we investigated whether diet during moult (inferred via stable isotope analysis of feather δ15N and δ13C) influenced plumage colouration. Our findings indicate that geographic variation, season and diet all influence individual differences in American redstart colouration, represented by both traditional and tetrahedral colour variables. The extent to which these factors influence colour expression however is largely dependent on the colour metric under study, likely because different colour metrics reflect different attributes of the feather (e.g. structural components versus pigment deposition). The effects of diet (δ15N) and season were pronounced for brightness, suggesting a strong effect of diet and feather wear/degradation on feather structure. Though hue, a metric that should strongly reflect pigment deposition, also changed from spring to fall, that effect was dependent on age, with only adults experiencing a reduction in ornamentation. Taken together, our results highlight the numerous sources of variation behind plumage coloration and underscores the difficulty of unraveling complex visual signaling systems, such as those in American redstarts

Observation of narrow Autler-Townes components in the resonant response of a dense atomic gas

We have experimentally studied the reflection of a weak probe beam from a dense atomic potassium vapor in the presence of a strong laser field tuned to the atomic resonance transition. We have observed an Autler-Townes doublet under hitherto unexplored conditions, namely that the Rabi frequency induced by the strong laser field is much smaller than the self-broadened width of the resonance transition of the unexcited vapor. We attribute our observation to a reduction of the atomic decoherence by the strong drive field. We present a theoretical model of nonlinear processes in a dense atomic gas to explain the observed results

Modeling Monetary Policy

We develop a macroeconomic framework where money issupplied against only few eligible securities in open marketoperations. The relationship between the policy rate,expected inflation and consumption growth is affected bymoney market conditions, i.e. the varying liquidity value ofeligible assets and the associated risk. This induces a liquiditypremium, which explains the observed systematic wedgebetween the policy rate and consumption Euler interest ratethat standard models equate. It further implies a dampenedresponse of consumption to policy rate shocks that is humpshapedwhen we account for realistic central bank transfersand the dynamics of bond holdings

An Interest Rate Peg Might Be Better than You Think

Active interest rate policy is frequently recommended based on its merits in reducing macroeconomic volatility and being a simple and transparent policy device. In a standard New Keynesian model, we show that an even simpler policy, namely an interest rate peg, can be welfare enhancing: The minimum state variable solution and an autoregessive solution under a peg can lead to lower welfare losses than the unique solution under an active interest rate rule. Given that a peg is usually blamed to facilitate endogenous fluctuations, we further show that a peg can be implemented in a way that ensures equilibrium determinacy

Using social media to understand adults' experiences of physical activity as a child living with type 1 diabetes

Diagnosis of type 1 diabetes (T1D) has serious, life changing implications. Learning to understand complex medication regimes and glucose regulation requires support and education. Introducing physical activity alongside these complexities brings additional challenges. It is known that physical activity levels in children with T1D are generally less than that of the general population1,2. Understanding energy expenditure and careful insulin adjustment/titration for physical activity participation requires ongoing, appropriate, individualised education and behavioural support 3 . Appropriate, person-centred and family based approaches to provide the right support and care need to be considered 3-5