357 research outputs found
Structure, rotational dynamics, and superfluidity of small OCS-doped He clusters
The structural and dynamical properties of OCS molecules solvated in Helium
clusters are studied using reptation quantum Monte Carlo, for cluster sizes
n=3-20 He atoms. Computer simulations allow us to establish a relation between
the rotational spectrum of the solvated molecule and the structure of the He
solvent, and of both with the onset of superfluidity. Our results agree with a
recent spectroscopic study of this system, and provide a more complex and
detailed microscopic picture of this system than inferred from experiments.Comment: 4 pages. TeX (requires revtex4) + 3 ps figures (1 color
The Invariant in Phonology. The role of salience and predictability
This aim of this thesis is to give a phonological account of acoustic variation and reduction. It is argued that phonological representations are uneven and include information about the relative strength of the segmental and subsegmental units composing them. This unevenness implies a distinction between the invariant â the âphonetic essenceâ of a word, which is practically undeletable â and other units which can be dispensed with under certain circumstances. In the first chapter I compare different theoretical approaches to the problem of acoustic variation, in particular with reference to generative phonology and exemplar-based theories. In the second chapter I propose a model which combines aspects of Optimality Theory, Element Theory and usage-based linguistics. Additionally, I discuss the role of acoustic salience in the formation of the invariant. In chapter three, typological and experimental data are examined in order to establish a salience scale for consonants. In chapter four, the results of the acoustic analysis of four dialogues extracted from a corpus of spoken Italian are presented. As expected, highly salient consonants are preserved to a greater extent than less salient ones. In chapter five I attempt to identify the phonological correlates of acoustic salience and discuss other factors which may favor reduction and deletion, among which predictability. In chapter six I draw some conclusions, deal with some pending issues and suggest future directions for research
HLA-C increases HIV-1 infectivity and is associated with gp120
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
La lecture, les formes et la vie : Entretien avec Marielle Macé
Dans son dernier livre, Façons de lire, maniĂšres dâĂȘtre, Marielle MacĂ© replace lâexpĂ©rience de lecture Ă lâintĂ©rieur dâune vaste « stylistique de lâexistence » ; elle Ă©tablit un lien entre cet Ă©largissement de la question du style aux formes de la vie, et ce que nous pouvons attendre des livres : la lecture lui apparaĂźt comme lâune de ces conduites par lesquelles, quotidiennement, nous donnons un aspect, une figure, des formes, des rythmes, quelque chose comme « un style » Ă notre existence. Son ouvrage part dâune rĂ©interprĂ©tation des rapports entre la littĂ©rature et la vie ; il pose que câest dans la vie elle-mĂȘme que les Ćuvres se tiennent, dĂ©posent leurs traces et exercent leur force. Il nây a pas dâun cĂŽtĂ© la littĂ©rature, et de lâautre la vie ; il y a au contraire, dans la vie elle-mĂȘme, des formes, des images, des styles dâĂȘtre qui circulent entre les sujets et les Ćuvres, qui les exposent, les animent, les affectent, les transforment (ou les laissent indiffĂ©rents). En sorte que les formes littĂ©raires se proposent dans la lecture comme de vĂ©ritables phrasĂ©s de la vie, engageant des conduites, des rythmes, des puissances de façonnement, des valeurs pratiques. Dans lâexpĂ©rience ordinaire et extraordinaire de la lecture, chacun peut alors se rĂ©approprier son rapport Ă soi, Ă son langage, Ă ses possibles, Ă ses modes dâĂȘtre, et la littĂ©rature apparaĂźt comme le lieu oĂč se mĂ©dite ce quâil entre de formes dans la vie
Phenotypical heterogeneity linked to adipose tissue dysfunction in patients with type 2 diabetes
Adipose tissue (AT) inflammation leads to increased free fatty acid (FFA) efflux and ectopic fat deposition, but whether AT dysfunction drives selective fat accumulation in specific sites remains unknown. The aim of the present study was to investigate the correlation between AT dysfunction, hepatic/pancreatic fat fraction (HFF, PFF) and the associated metabolic phenotype in patients with Type 2 diabetes (T2D). Sixty-five consecutive T2D patients were recruited at the Diabetes Centre of Sapienza University, Rome, Italy. The study population underwent clinical examination and blood sampling for routine biochemistry and calculation of insulin secretion [homoeostasis model assessment of insulin secretion (HOMA-ÎČ%)] and insulin-resistance [homoeostasis model assessment of insulin resistance (HOMA-IR) and adipose tissue insulin resistance (ADIPO-IR)] indexes. Subcutaneous (SAT) and visceral (VAT) AT area, HFF and PFF were determined by magnetic resonance. Some 55.4% of T2D patients had non-alcoholic fatty liver disease (NAFLD); they were significantly younger and more insulin-resistant than non-NAFLD subjects. ADIPO-IR was the main determinant of HFF independently of age, sex, HOMA-IR, VAT, SAT and predicted severe NAFLD with the area under the receiver operating characteristic curve (AUROC)=0.796 (95% confidence interval: 0.65-0.94, P=0.001). PFF was independently associated with increased total adiposity but did not correlate with AT dysfunction, insulin resistance and secretion or NAFLD. The ADIPO-IR index was capable of predicting NAFLD independently of all confounders, whereas it did not seem to be related to intrapancreatic fat deposition; unlike HFF, higher PFF was not associated with relevant alterations in the metabolic profile. In conclusion, the presence and severity of AT dysfunction may drive ectopic fat accumulation towards specific targets, such as VAT and liver, therefore evaluation of AT dysfunction may contribute to the identification of different risk profiles among T2D patients
integration of enhanced optical tracking techniques and imaging in igrt
Patient setup/Optical tracking/IGRT/Treatment surveillance. In external beam radiotherapy, modern technologies for dynamic dose delivery and beam conformation provide high selectivity in radiation dose administration to the pathological volume. A comparable accuracy level is needed in the 3-D localization of tumor and organs at risk (OARs), in order to accomplish the planned dose distribution in the reality of each irradiation session. In-room imaging techniques for patient setup verification and tumor targeting may benefit of the combined daily use of optical tracking technologies, supported by techniques for the detection and compensation of organ motion events. Multiple solutions to enhance the use of optical tracking for the on-line correction of target localization uncertainties are described, with specific emphasis on the compensation of setup errors, breathing movements and non-rigid deformations. The final goal is the implementation of customized protocols where appropriate external landmarks, to be tracked in real-time by means of noninvasive optical devices, are selected as a function of inner target localization. The presented methodology features high accuracy in patient setup optimization, also providing a valuable tool for on-line patient surveillance, taking into account both breathing and deformation effects. The methodic application of optical tracking is put forward to represent a reliable and low cost procedure for the reduction of safety margins, once the patient-specific correlation between external landmarks and inner structures has been established. Therefore, the integration of optical tracking with in-room imaging devices is proposed as a way to gain higher confidence in the framework of Image Guided Radiation Therapy (IGRT) treatments
Force produced after stretch in sarcomeres and half-sarcomeres isolated from skeletal muscles
The goal of this study was to evaluate if isolated sarcomeres and half-sarcomeres produce a long-lasting increase in force after a stretch is imposed during activation. Single and half-sarcomeres were isolated from myofibrils using micro-needles, which were also used for force measurements. After full force development, both preparations were stretched by different magnitudes. The sarcomere length (SL) or half-sarcomere length variations (HSL) were extracted by measuring the initial and final distances from the Z-line to the adjacent Z-line or to a region externally adjacent to the M-line of the sarcomere, respectively. Half-sarcomeres generated approximately the same amount of isometric force (29.0 ± SD 15.5â
nN·Όm(â2)) as single sarcomeres (32.1 ± SD 15.3â
nN·Όm(â2)) when activated. In both cases, the steady-state forces after stretch were higher than the forces during isometric contractions at similar conditions. The results suggest that stretch-induced force enhancement is partly caused by proteins within the half-sarcomere
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