Assessment of seismic performance of adobe structures in Pakistan and Portugal

Adobe buildings exist in different parts of the world. The construction of these buildings can be carried out economically, using locally available materials and skills that do not require use of modern machinery. Therefore, adobe buildings provide an economic housing option. The construction of adobe structures is carried out based on traditional construction practices which vary from region to region. This paper presents the results of a study which was conducted to study the construction practices of adobe buildings in Pakistan and Portugal in the context of their seismic vulnerability. The adobe buildings in both these countries were found to be subjected to seismic hazard levels which, although is low in some regions, may cause significant damages. Lack of essential elements or details for the adequate seismic performance was found in the adobe buildings in both regions

Does the shape of inflow velocity profiles affect hemodynamics in computational coronary artery models?

In this study, the impact of velocity inflow profiles shape on computational hemodynamic models of coronary arteries was investigated. To this purpose, 3D realistic velocity profiles were generated analytically and prescribed as inflow boundary condition and the impact on near-wall and intravascular flow was assessed. The results suggest that the impact of the shape of inflow velocity profiles on simulated coronary hemodynamics is limited to the proximal segment, while the global hemodynamics is poorly affected

Experimental evidence of antiproton reflection by a solid surface

We report here experimental evidence of the reflection of a large fraction of a beam of low energy antiprotons by an aluminum wall. This derives from the analysis of a set of annihilations of antiprotons that come to rest in rarefied helium gas after hitting the end wall of the apparatus. A Monte Carlo simulation of the antiproton path in aluminum indicates that the observed reflection occurs primarily via a multiple Rutherford-style scattering on Al nuclei, at least in the energy range 1-10 keV where the phenomenon is most visible in the analyzed data. These results contradict the common belief according to which the interactions between matter and antimatter are dominated by the reciprocally destructive phenomenon of annihilation.Comment: 5 pages with 5 figure

Limits on the low energy antinucleon-nucleus annihilations from the Heisenberg principle

We show that the quantum uncertainty principle puts some limits on the effectiveness of the antinucleon-nucleus annihilation at very low energies. This is caused by the fact that the realization a very effective short-distance reaction process implies information on the relative distance of the reacting particles. Some quantitative predictions are possible on this ground, including the approximate A-independence of antinucleon-nucleus annihilation rates.Comment: 10 pages, no figure

Difficoltà di apprendimento: il ruolo dell’attività motoria finalizzata

La forma di numeri e lettere, la loro successione da sinistra a destra che struttura parole e frasi, la memorizzazione del tracciato dei diversi caratteri, la coordinazione della muscolatu- ra oculare utilizzata negli atti dello scrivere e del leggere sono tutti elementi di qualit\ue0 mo- toria e sequenziale che l\u2019individuo deve automatizzare per affrontare il compito di appren- dere. La scarsa efficienza di alcune delle funzioni chiave della motricit\ue0, come la lateraliz- zazione e la coordinazione oculo manuale, incide pesantemente nell\u2019organizzazione delle procedure della letto-scrittura e del calcolo. Il nostro studio si pone lo scopo di esemplifi- care come l\u2019abilitazione coordinativa possa attenuare significativamente i DSA attraverso in- terventi di motricit\ue0 finalizzata. Il movimento umano inteso come \u201catto in funzione di uno scopo\u201d e proposto con una didattica protetta e di gruppo si \ue8 dimostrata essere in grado di ripristinare una viabilit\ue0 neuro motoria pi\uf9 funzionale a raggiungere il successo nelle pratiche scolastiche.A set of motor and sequential skills must be automatized in order to carry out the task of learning. Indeed, the learning process requires the visual search of number/letter shapes, the analysis of left-to-right sequences, memorization of letters shape tracing and eye muscle coordination in reading and writing. The low efficiency of some of the key functions within motor scheme, such as lateralization and eye-hand coordination, negatively affects the organization of reading-writing and calculation processes. The aim of our study was the assessment of improvements within reading/writing/ calculation outcomes, in LSD children after a specific motor sequence training. In particular, skill coordination performance leaded all children to an important improvements during specific trials about the scholastic practice. Specific and ad-personam sequence of exercise could be an elective teaching methodology to over-stimolate the neuro-motor viabilit

A Periodic Transmission Line Model for Body Channel Communication

Body channel communication (BCC) is a technique for data transmission exploiting the human body as communication channel. Even though it was pioneered about 25 years ago, the identification of a good electrical model behind its functioning is still an open research question. The proposed distributed model can then serve as a supporting tool for the design, allowing to enhance the performances of any BCC system. A novel finite periodic transmission line model was developed to describe the human body as transmission medium. According to this model, for the first time, the parasitic capacitance between the transmitter and the receiver is assumed to depend on their distance. The parameters related to the body and electrodes are acquired experimentally by fitting the bio-impedentiometric measurements, in the range of frequencies from 1 kHz to 1 MHz, obtaining a mean absolute error lower than 4° and 30 $Omega$ for the phase angle and impedance modulus, respectively. The proposed mathematical framework has been successfully validated by describing a ground-referred and low-complexity system called Live Wire, suitable as supporting tool for visually impaired people, and finding good agreement between the measured and the calculated data, marking a ±3% error for communication distances ranging from 20 to 150 cm. In this work we introduced a new circuital approach, for capacitive-coupling systems, based on finite periodic transmission line, capable to describe and model BCC systems allowing to optimize the performances of similar systems

Constructionist Attempts at Supporting the Learning of Computer Programming: A Survey

Although programming is often seen as a key element of constructionist approaches, the research on learning to program through a constructionist strategy is somewhat limited, mostly focusing on how to bring the abstract and formal nature of programming languages into \u201cconcrete\u201d, possibly tangible objects, graspable even by children with limited abstraction power. We survey the literature in programming education and analyse some programming languages designed to help novices from a constructionist perspective

Three Dimensional Annihilation Imaging of Antiprotons in a Penning Trap

We demonstrate three-dimensional annihilation imaging of antiprotons trapped in a Penning trap. Exploiting unusual feature of antiparticles, we investigate a previously unexplored regime in particle transport; the proximity of the trap wall. Particle loss on the wall, the final step of radial transport, is observed to be highly non-uniform, both radially and azimuthally. These observations have considerable implications for the production and detection of antihydrogen atoms.Comment: Invited Talk at NNP03, Workshop on Non-Neutral Plasmas, 200

Positron plasma diagnostics and temperature control for antihydrogen production

Production of antihydrogen atoms by mixing antiprotons with a cold, confined, positron plasma depends critically on parameters such as the plasma density and temperature. We discuss non-destructive measurements, based on a novel, real-time analysis of excited, low-order plasma modes, that provide comprehensive characterization of the positron plasma in the ATHENA antihydrogen apparatus. The plasma length, radius, density, and total particle number are obtained. Measurement and control of plasma temperature variations, and the application to antihydrogen production experiments are discussed.Comment: 5 pages, 4 figures, to be published in Phys. Rev. Let

Follow-Up Assessment of Intracranial Aneurysms Treated with Endovascular Coiling: Comparison of Compressed Sensing and Parallel Imaging Time-of-Flight Magnetic Resonance Angiography

The aim of our study was to compare compressed sensing (CS) time-of-flight (TOF) magnetic resonance angiography (MRA) with parallel imaging (PI) TOF MRA in the evaluation of patients with intracranial aneurysms treated with coil embolization or stent-assisted coiling. We enrolled 22 patients who underwent follow-up imaging after intracranial aneurysm coil embolization. All patients underwent both PI TOF and CS TOF MRA during the same examination. Image evaluation aimed to compare the performance of CS to PI TOF MRA in determining the degree of aneurysm occlusion, as well as the depiction of parent vessel and vessels adjacent to the aneurysm dome. The reference standard for the evaluation of aneurysm occlusion was PI TOF MRA. The inter-modality agreement between CS and PI TOF MRA in the evaluation of aneurysm occlusion was almost perfect (κ = 0.98, p < 0.001) and the overall inter-rater agreement was substantial (κ = 0.70, p < 0.001). The visualization of aneurysm parent vessel in CS TOF images compared with PI TOF images was evaluated to be better in 11.4%, equal in 86.4%, and worse in 2.3%. CS TOF MRA, with almost 70% scan time reduction with respect to PI TOF MRA, yields comparable results for assessing the occlusion status of coiled intracranial aneurysms. Short scan times increase patient comfort, reduce the risk of motion artifacts, and increase patient throughput, with a resulting reduction in costs. CS TOF MRA may therefore be a potential replacement for PI TOF MRA as a first-line follow-up examination in patients with intracranial aneurysms treated with coil embolization