Second-order matter perturbations in a LambdaCDM cosmology and non-Gaussianity

We obtain exact expressions for the effect of primordial non-Gaussianity on the matter density perturbation up to second order in a LambdaCDM cosmology, fully accounting for the general relativistic corrections arising on scales comparable with the Hubble radius. We present our results both in the Poisson gauge and in the comoving and synchronous gauge, which are relevant for comparison to different cosmological observables.Comment: 15 pages. LaTeX file. Invited article for CQG issue on non-linear cosmolog

At the heart of it: Middle school writers use talk and multimedia journals to forge a literate classroom community

In this research study, I investigated how middle school writers use talk and multi-media journals to forge a literate classroom community. Talk and multi-media journals helped middle school writers to construct and maintain a safe, caring, supportive, and respectful learning environment where transformative literacy and learning experiences could take place. Classroom talk played a vital role in improving students\u27 relationships in this literate classroom community and engaging them in meaningful ways with their multi-media journals. During the research study, explicit instruction in the social aspects of talk emerged as important as explicit instruction in language arts content. The multi-media approach to journal writing evolved from my own membership in a Women\u27s Journal Group. The multi-media approach to journal writing involved the use of other mediums, especially the visual arts, while writing. Students reported that the multi-media journals helped them to begin and continue writing as well as increased their enjoyment of writing. I conducted this teacher research study over a six month period. I employed the tools and procedures of ethnographic and qualitative research in the data collection and analysis

Enhancing the online decision-making process by using augmented reality: a two country comparison of youth markets

Although online stores extend the traditional offer of the brick and mortar ones, the limited possibilities to virtually try the product before the effective buying makes the online purchase decision a complex process for consumers. Therefore, online retailers face new challenges for supporting consumers consisting of the introduction of advanced technologies such as augmented reality systems. The present study investigates the effect of augmented reality technologies on consumer behaviour within the online retail environments, by comparing two different cultural settings. Drawing upon the technology acceptance model (TAM), new constructs related to the technology characteristics (e.g. quality of information, aesthetic quality, interactivity, and response time) developed a new conceptual model. This model has been tested for a new technology for virtual try-on (a smart mirror for virtual glasses). Focusing on young consumers, data collected in Italy and Germany yielding a total of 318 participants was used. Findings across these two markets reflect cross-market similarities, but also dissimilarities, related to consumers’ motivation to employ augmented reality systems for supporting their online purchase decision. These insights should prove helpful to retailers in better manage the online channels, that could be easily extended to the mobile one

Modello numerico per la simulazione e l’ottimizzazione di controlli non distruttivi con ultrasuoni

I controlli non distruttivi basati sull’impiego di ultrasuoni sono ampiamente usati per la loro efficacia e affidabilità nel rilevamento di difetti. La generazione di onde ultrasonore e la propagazione in strutture di forma non regolare sono difficili da analizzare, soprattutto se la sorgente impiegata è un laser. Le tecniche numeriche per la simulazione del fenomeno reperibili in letteratura mostrano limiti di applicabilità per frequenze nel campo dei MHz e lunghezze d’onda molto corte. In questo lavoro presentiamo un metodo numerico in grado di risolvere accuratamente ed efficientemente problemi di generazione di onde ultrasonore tramite laser, con frequenze nel range dei MHz, e di propagazione in corpi relativamente estesi. La ricezione viene simulata con la propagazione degli ultrasuoni in aria, al fine di poter ottimizzare la configurazione completa per controlli non distruttivi con ultrasuoni senza contatto. Diverse configurazioni di ispezione sono state prima simulate tramite l’analisi numerica e poi riprodotte sperimentalmente per confrontare i risultati

Cerebral hemodynamics on MR perfusion images before and after bypass surgery in patients with giant intracranial aneurysms

Preoperative assessment of the anatomy and dynamics of cerebral circulation for patients with giant intracranial aneurysm can improve both outcome prediction and therapeutic approach. The aim of our study was to use perfusion MR imaging to evaluate cerebral hemodynamics in such patients before and after extraintracranial high-flow bypass surgery. METHODS: Five patients with a giant aneurysm of the intracranial internal carotid artery underwent MR studies before, 1 week after, and 1 month after high-flow bypass surgery. We performed MR and digital subtraction angiography, and conventional and functional MR sequences (diffusion and perfusion). Surgery consisted of middle cerebral artery (MCA)-internal carotid artery bypass with saphenous vein grafts (n = 4) or MCA-external carotid artery bypass (n = 1). RESULTS: In four patients, MR perfusion study showed impaired hemodynamics in the vascular territory supplied by the MCA of the aneurysm side, characterized by significantly reduced mean cerebral blood flow (CBF), whereas mean transit time (MTT) and regional cerebral blood volume (rCBV) were either preserved, reduced, or increased. After surgery, angiography showed good canalization of the bypass graft. MR perfusion data obtained after surgery showed improved cerebral hemodynamics in all cases, with a return of CBF index (CBFi), MTT, and rCBV to nearly normal values. CONCLUSION: Increased MTT with increased or preserved rCBV can be interpreted as a compensatory vasodilatory response to reduced perfusion pressure, presumably from compression and disturbed flow in the giant aneurysmal sac. When maximal vasodilation has occurred, however, the brain can no longer compensate for diminished perfusion by vasodilation, and rCBV and CBFi diminish. Bypass surgery improves hemodynamics, increasing perfusion pressure and, thus, CBFi. Perfusion MR imaging can be used to evaluate cerebral hemodynamics in patients with intracranial giant aneurysm.BACKGROUND AND PURPOSE: Preoperative assessment of the anatomy and dynamics of cerebral circulation for patients with giant intracranial aneurysm can improve both outcome prediction and therapeutic approach. The aim of our study was to use perfusion MR imaging to evaluate cerebral hemodynamics in such patients before and after extraintracranial high-flow bypass surgery. METHODS: Five patients with a giant aneurysm of the intracranial internal carotid artery underwent MR studies before, 1 week after, and 1 month after high-flow bypass surgery. We performed MR and digital subtraction angiography, and conventional and functional MR sequences (diffusion and perfusion). Surgery consisted of middle cerebral artery (MCA)-internal carotid artery bypass with saphenous vein grafts (n = 4) or MCA-external carotid artery bypass (n = 1). RESULTS: In four patients, MR perfusion study showed impaired hemodynamics in the vascular territory supplied by the MCA of the aneurysm side, characterized by significantly reduced mean cerebral blood flow (CBF), whereas mean transit time (MTT) and regional cerebral blood volume (rCBV) were either preserved, reduced, or increased. After surgery, angiography showed good canalization of the bypass graft. MR perfusion data obtained after surgery showed improved cerebral hemodynamics in all cases, with a return of CBF index (CBFi), MTT, and rCBV to nearly normal values. CONCLUSION: Increased MTT with increased or preserved rCBV can be interpreted as a compensatory vasodilatory response to reduced perfusion pressure, presumably from compression and disturbed flow in the giant aneurysmal sac. When maximal vasodilation has occurred, however, the brain can no longer compensate for diminished perfusion by vasodilation, and rCBV and CBFi diminish. Bypass surgery improves hemodynamics, increasing perfusion pressure and, thus, CBFi. Perfusion MR imaging can be used to evaluate cerebral hemodynamics in patients with intracranial giant aneurysm

Regulatory framework of pharmaceutical compounding and actual developments of legislation in Europe

Pharmaceutical preparations are medicines that the pharmacist makes for the special needs of the patients that the pharmaceutical industry cannot comply for economic and logistic reasons. Pharmacy compounding is still an important component of pharmacy practice and a valuable therapeutical service that is an integrant part of the modern health care system, but its legislation is not harmonized among European and US countries.In 2011 the Committee of Ministers of the Council of Europe has adopted a Resolution on quality and safety assurance requirements for medicinal products prepared in pharmacies for the special needs of patients. Aim of this resolution is to harmonize quality assurance and standards for pharmacy-made medicinal products among European countries and to pass the gap in quality assurance and standards between preparation in pharmacies and medicines prepared by the pharmaceutical industry. This article will analyze the actual rules and technical norms that regulate compounding activity and the expectations resultants from the new European and US laws

Mechanical properties of carbon nanotube fibres: St Venant's principle at the limit and the role of imperfections

Carbon nanotube (CNT) fibres, especially if perfect in terms of purity and alignment, are of extreme anisotropy. With their high axial strength but ready slippage between the CNTs, there is utmost difficulty in transferring the force applied uniformly. Finite element analysis is used to predict the stress distribution in CNT fibres loaded by grips attached to their surface, along with the resulting tensile stress-strain curves. This study demonstrates that in accordance with St Venant’s principle very considerable length-to-diameter ratios (~ 103) are required before the stress becomes uniform across the fibre, even at low strains. It is proposed that lack of perfect orientation and presence of carbonaceous material between bundles greatly enhances the stress transfer, thus increasing the load it can carry before failing by shear. It is suggested that a very high strength batch of fibres previously observed experimentally had an unusually high concentration of internal particles, meaning that the pressure exerted by the grips would assist stress transfer between the layers. We conclude, that the strength of CNT fibres depends on the specific testing geometries and that imperfections, whether by virtue of less-than-perfect orientation or of embedded impurities, are actually major positive contributors to the observed strength.The authors are grateful to USN ONR GLOBAL for the provision of funding under award number N62909-14-1-N200. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Office of Naval Research.This is the accepted manuscript. The final version is available at http://www.sciencedirect.com/science/article/pii/S0008622315004728

The Loma Negra braqui-anticline: A Quaternary folding structure in the Central Precordillera, San Juan province

Sobre el piedemonte oriental de la sierra de Talacasto, en Precordillera Central, se reconocieron numerosas evidencias de fallamiento activo y plegamiento cuaternario. En este trabajo se presentan los resultados preliminares de los estudios geomorfológicos realizados en el anticlinal de Loma Negra y se describen las principales estructuras de deformación cuaternarias reconocidas. La expresión morfotectónica de las fallas activas identificadas incluye escarpas de fallas a contrapendiente y a favor de la misma, distintos niveles de abanicos aluviales colgados y/o basculados, discordancias progresivas, plegamiento reciente en depósitos fangloméradicos pleistocenos y control de la red de drenaje. Las evidencias morfotectónicas identificadas en los depósitos cuaternarios indican una deformación progresiva hacia el este, con predominio de fallamiento inverso y plegamiento que migra en este sentido.Several evidences of Quaternary active faulting and folding were recognized on the eastern piedmont of the Sierra de Talacasto in Central Precordillera. In this paper we present the preliminary results of geomorphological studies carried out in the Loma Negra anticline and major Quaternary deformation structures are described. Morphotectonic expression of the identified active faults includes counter-slope or favor-slope scarps and different levels of hanging and / or tilted alluvial fans, progressive unconformities, recent folding of Pleistocene fanglomerates and control of the drainage network. Morphotectonic evidence in the Quaternary deposits indicates a progressive deformation eastward, dominated by reverse faulting and folding that migrate in this sense.Fil: Perucca, Laura Patricia A.. Universidad Nacional de San Juan. Facultad de Cs.exactas Fisicas y Naturales. Instituto de Geologia "dr.emiliano Aparicio". Gabinete de Neotectonica y Geomorfologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Juan. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Pantano Zuñiga, Ana Vanesa. Universidad Nacional de San Juan. Facultad de Cs.exactas Fisicas y Naturales. Instituto de Geologia "dr.emiliano Aparicio". Gabinete de Neotectonica y Geomorfologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Juan. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Vargas, Nicolás. CHISÑANCO SRL.; Argentin