Dusty Planetary Systems

Extensive photometric stellar surveys show that many main sequence stars show emission at infrared and longer wavelengths that is in excess of the stellar photosphere; this emission is thought to arise from circumstellar dust. The presence of dust disks is confirmed by spatially resolved imaging at infrared to millimeter wavelengths (tracing the dust thermal emission), and at optical to near infrared wavelengths (tracing the dust scattered light). Because the expected lifetime of these dust particles is much shorter than the age of the stars (>10 Myr), it is inferred that this solid material not primordial, i.e. the remaining from the placental cloud of gas and dust where the star was born, but instead is replenished by dust-producing planetesimals. These planetesimals are analogous to the asteroids, comets and Kuiper Belt objects (KBOs) in our Solar system that produce the interplanetary dust that gives rise to the zodiacal light (tracing the inner component of the Solar system debris disk). The presence of these "debris disks" around stars with a wide range of masses, luminosities, and metallicities, with and without binary companions, is evidence that planetesimal formation is a robust process that can take place under a wide range of conditions. This chapter is divided in two parts. Part I discusses how the study of the Solar system debris disk and the study of debris disks around other stars can help us learn about the formation, evolution and diversity of planetary systems by shedding light on the frequency and timing of planetesimal formation, the location and physical properties of the planetesimals, the presence of long-period planets, and the dynamical and collisional evolution of the system. Part II reviews the physical processes that affect dust particles in the gas-free environment of a debris disk and their effect on the dust particle size and spatial distribution.Comment: 68 pages, 25 figures. To be published in "Solar and Planetary Systems" (P. Kalas and L. French, Eds.), Volume 3 of the series "Planets, Stars and Stellar Systems" (T.D. Oswalt, Editor-in-chief), Springer 201

Should the poultry red mite Dermanyssus gallinae be of wider concern for veterinary and medical science?

The poultry red mite Dermanyssus gallinae is best known as a threat to the laying-hen industry; adversely affecting production and hen health and welfare throughout the globe, both directly and through its role as a disease vector. Nevertheless, D. gallinae is being increasingly implemented in dermatological complaints in non-avian hosts, suggesting that its significance may extend beyond poultry. The main objective of the current work was to review the potential of D. gallinae as a wider veterinary and medical threat. Results demonstrated that, as an avian mite, D. gallinae is unsurprisingly an occasional pest of pet birds. However, research also supports that these mites will feed from a range of other animals including: cats, dogs, rodents, rabbits, horses and man. We conclude that although reported cases of D. gallinae infesting mammals are relatively rare, when coupled with the reported genetic plasticity of this species and evidence of permanent infestations on non-avian hosts, potential for host-expansion may exist. The impact of, and mechanisms and risk factors for such expansion are discussed, and suggestions for further work made. Given the potential severity of any level of host-expansion in D. gallinae, we conclude that further research should be urgently conducted to confirm the full extent of the threat posed by D. gallinae to (non-avian) veterinary and medical sectors

A transcriptomic analysis of Echinococcus granulosus larval stages:implications for parasite biology and host adaptation

The cestode Echinococcus granulosus--the agent of cystic echinococcosis, a zoonosis affecting humans and domestic animals worldwide--is an excellent model for the study of host-parasite cross-talk that interfaces with two mammalian hosts. To develop the molecular analysis of these interactions, we carried out an EST survey of E. granulosus larval stages. We report the salient features of this study with a focus on genes reflecting physiological adaptations of different parasite stages.We generated ~10,000 ESTs from two sets of full-length enriched libraries (derived from oligo-capped and trans-spliced cDNAs) prepared with three parasite materials: hydatid cyst wall, larval worms (protoscoleces), and pepsin/H(+)-activated protoscoleces. The ESTs were clustered into 2700 distinct gene products. In the context of the biology of E. granulosus, our analyses reveal: (i) a diverse group of abundant long non-protein coding transcripts showing homology to a middle repetitive element (EgBRep) that could either be active molecular species or represent precursors of small RNAs (like piRNAs); (ii) an up-regulation of fermentative pathways in the tissue of the cyst wall; (iii) highly expressed thiol- and selenol-dependent antioxidant enzyme targets of thioredoxin glutathione reductase, the functional hub of redox metabolism in parasitic flatworms; (iv) candidate apomucins for the external layer of the tissue-dwelling hydatid cyst, a mucin-rich structure that is critical for survival in the intermediate host; (v) a set of tetraspanins, a protein family that appears to have expanded in the cestode lineage; and (vi) a set of platyhelminth-specific gene products that may offer targets for novel pan-platyhelminth drug development.This survey has greatly increased the quality and the quantity of the molecular information on E. granulosus and constitutes a valuable resource for gene prediction on the parasite genome and for further genomic and proteomic analyses focused on cestodes and platyhelminths

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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the measurement of statistical reasoning in verbal numerical and graphical forms a pilot study

Numerous subjects have trouble in understanding various conceptions connected to statistical problems. Research reports how students' ability to solve problems (including statistical problems) can be influenced by exhibiting proofs. In this work we aim to contrive an original and easy instrument able to assess statistical reasoning on uncertainty and on association, regarding two different forms of proof presentation: pictorial-graphical and verbal–numerical. We have conceived eleven pairs of simple problems in the verbal–numerical and pictorial–graphical form and we have presented the proofs to 47 undergraduate students. The purpose of our work was to evaluate the goodness and reliability of these problems in the assessment of statistical reasoning. Each subject solved each pair of proofs in the verbal-numerical and in the pictorial–graphical form, in different problem presentation orders. Data analyses have highlighted that six out of the eleven pairs of problems appear to be useful and adequate to estimate statistical reasoning on uncertainty and that there is no effect due to the order of presentation in the verbal–numerical and pictorial–graphical form

Measurement of urinary collagen cross-links indicate response to therapy in patients with breast cancer and bone metastases

Objective assessment of response in bone metastases from breast cancer using radiological techniques takes up to 6 months of treatment to be certain of a response, and sclerotic metastases are not evaluable. Standard serum and urinary tumour markers may not always be utilized to predict response, as they may not be elevated, and therefore may not change on treatment. The development of the urinary pyridinoline cross-link assays which measure mature bone breakdown products have been shown to be highly sensitive and specific as a measure of bone change in osteoporosis. We have measured pyridinoline (Pyr) and deoxypyridinoline (Dpyr) cross-links sequentially in 36 breast cancer patients with bone metastases, to determine if the measurement of these analytes predicts response at an earlier stage than radiological assessment. Response was assessed by UICC criteria. Seventeen women responded to hormonal therapy, whilst 19 developed progressive disease. Both Pyr and Dpyr increased sequentially in women with progressive disease with changes becoming apparent by 8 weeks (P < 0.03). In responding women, cross-link levels did not change significantly. Pyr and Dpyr were more sensitive and specific than the standard serum tumour marker CA 15-3. Urinary cross-link measurements provide a novel objective method of assessing response to treatment in women with bone metastases. Initial elevated urinary cross-link markers identify patients who tend not to respond to changes in hormonal therap

Students’ satisfaction and teaching efficiency of university offer

This study analyses the factors affecting students’ satisfaction with university experience, focusing on the aspects characterising the teaching efficiency of educational offer. For this purpose, organisation of teaching activities, available information, teaching materials, and other facilities offered to students to make their learning experience more successful, are considered as indicators of teaching efficiency. Our interest in this topic is justified by the importance that students’ satisfaction assumes, not only as indicator of the quality of educational services but also for its relationship with overall life satisfaction and subjective well-being. A structural equation model with latent variables is estimated by using survey and administrative data of the University of Pisa. Main findings seem to show that teaching efficiency has a positive effect on satisfaction and suggest that whenever it is inadequate, or at least, considered as such, students are less satisfied for their university experience. The effects of other factors on students’ satisfaction such as studies organisation, social capital and internship experience are also discussed