Advanced optical microscopies for materials: new trends

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/32166This article summarizes the new trends of Optical Microscopy applied to Materials, with examples of applications that illustrate the capabilities of the technique

Alan Turing and the Cognitive Foundation of the Concept of Algorithm

The work of Alan Turing (1936) set a milestone for the foundation of the concept of algorithm by grounding the notion of effective procedure on a special type of real cognitive phenomenon, namely, that of a human being performing rule-based symbolic transformations with the only aid of paper and pencil. In this work, after a brief historical overview, we show how Turing arrived at a negative solution of the decidability problem for first order logic and in which sense Turing’s explication of the intuitive concept of effective procedure is sufficient to justify Church’s Thesis. We then present a cognitive interpretation of Turing’s theory of computation, according to which Turing machines are viewed as models of real phenomena of mind-environment interaction

Distribution of Caulerpa taxifolia var. distichophylla (Sonder) Verlaque, Huisman & Procaccini in the Mediterranean Sea

The Non-Indigenous Species (NIS) Caulerpa taxifolia var. distichophylla (Sonder) Verlaque, Huisman & Procaccini has been reported for the first time in the Mediterranean Sea along the coast of South Turkey. This NIS is actively expanding into the Eastern and Western Mediterranean Sea. In this paper, we present an overview of the current distribution of this alga in the Mediterranean Sea, based on relevant scientific publications, grey literature and personal observations. New records from the Sicilian coast (Italy) are also reported. Caulerpa taxifolia var. distichophylla was found over a wide range of environmental conditions (depth, light and substratum), suggesting a broad ecological plasticity of this alga which makes it a poten- tial threat for the Mediterranean benthic communities. In this respect, artificial structures, often linked to harbours and maritime traffic, seem to provide suitable habitats for this NIS. Since maritime traffic is intense in the Mediterranean Sea, further expansion of C. taxifolia var. distichophylla in this region is to be expected. For this reason, it is very important to build up an overview on the current distribution of the species and its possible pattern of colonisation in relation to environmental conditions, as well as in view of future climate change scenarios

Mechanisms of electric-field-induced alignment of block copolymer lamellae

We demonstrate that two mechanisms of lamellae reorientation observed experimentally under applied electric field [A. Böker H. Elbs, H. Hänsel, A. Knoll, S. Ludwigs, H. Zettl, V. Urban, V. Abetz, A. H. E. Müller and G. Krausch, Phys. Rev. Lett., 2002, 89, 135502] which have been previously described within dynamic self consistent field theory [A. V. Zvelindovsky and G. J. A. Sevink, Phys. Rev. Lett., 2003, 90, 049601] can be fully explained within a much more simple model using the Ginzburg–Landau Hamiltonian. A third alignment mechanism has been identified which was not previously reported. A more complete picture of reorientation under electric field emerges that clarifies the crucial role of structural defects

Specificità dei test cardio-polmonari nel nuoto: comparazione tra il nuoto trattenuto e test aspecifici di laboratorio

The purpose of this study is to compare maximal oxygen uptake (VO 2max), maximal heart rate (HRmax), and anaerobic threshold (AT) obtained by a swimming test (SW) and three other testing procedures: cycling (CY), running (RU), and arm cranking (AC). On separate day and randomly assigned, 12 male swimmers (age 19.2 ± 0.8 years, weight 68.9 ± 1.6 kg, and height 177.3 ± 1.7 cm), completed SW, CY, RU, and AC incremental tests to exhaustion. VO2max, HRmax, and AT were measured by a portable gas analyzer. To permit expired gases collection during SW testing, the device was connected to a modified snorkel system. During the SW the athletes showed a higher VO2max compared to the CY and the AC tests. There was no significant difference in VO2max between the SW and the RU test. The AT occurred at higher workloads during SW in comparison to the other tests. Moreover, the SW test induced a lower HR response with respect to the other tests. These results do not support the use of any unspecific testing procedures to estimate VO2max, HRmax, and AT for swimming. Thus, swimmers should be evaluated in their specific activity since prediction of physiological parameters for swimming from other kinds of efforts can be misleading. The most specific parameter appears to be AT, which showed the most relevant difference between the SW and the other tests

Specificità dei test cardio-polmonari nel nuoto: comparazione tra il nuoto trattenuto e test aspecifici di laboratorio

The purpose of this study is to compare maximal oxygen uptake (VO 2max), maximal heart rate (HRmax), and anaerobic threshold (AT) obtained by a swimming test (SW) and three other testing procedures: cycling (CY), running (RU), and arm cranking (AC). On separate day and randomly assigned, 12 male swimmers (age 19.2 ± 0.8 years, weight 68.9 ± 1.6 kg, and height 177.3 ± 1.7 cm), completed SW, CY, RU, and AC incremental tests to exhaustion. VO2max, HRmax, and AT were measured by a portable gas analyzer. To permit expired gases collection during SW testing, the device was connected to a modified snorkel system. During the SW the athletes showed a higher VO2max compared to the CY and the AC tests. There was no significant difference in VO2max between the SW and the RU test. The AT occurred at higher workloads during SW in comparison to the other tests. Moreover, the SW test induced a lower HR response with respect to the other tests. These results do not support the use of any unspecific testing procedures to estimate VO2max, HRmax, and AT for swimming. Thus, swimmers should be evaluated in their specific activity since prediction of physiological parameters for swimming from other kinds of efforts can be misleading. The most specific parameter appears to be AT, which showed the most relevant difference between the SW and the other tests

The Edible sea urchin <i>Paracentrotus lividus</i> (Lamarck, 1816): a valuable resource for fisheries and aquaculture purposes in Sardinia (Central-western Mediterranean)

In this study, several research approaches were used to increase the knowledge on the Mediterranean sea urchin Paracentrotus lividus. Morphometric characters and gonad indexes of sea urchin populations were monitored during one year to examine possible differences among seasons in 3 locations of Alghero Bay (NW Sardinia). Moreover, 2 experiments to test somatic growth, and gonad and alimentary indexes of laboratory-reared specimens fed an artificial diet were also carried out. The experiments lasted 16 and 10 weeks in Scotland and in Sardinia, respectively. In the latter, proximate composition and acidic profile of the sea urchins gonads were also assessed. Samples from natural populations were used as a control. Significant differences between reared and wild specimens were found, both regarding proximate composition (except for total lipids) and fatty acid profile. The results obtained confirm the effectiveness of the diet and rearing method used in enhancing sea urchins’ growth. Finally, an economical analysis on profitability and sustainability of P. lividus fisheries in Sardinia was performed. Firms operating with different harvesting methods were analysed, obtaining an overview of the current situation in terms of strengths and weaknesses of restrictions on the harvesting of this species. This information can be used by policy makers to implement important changes to the current fishing policy, by guaranteeing profitability for fishermen and conservation of wild stocks

Hybrid time-dependent Ginzburg-Landau simulations of block copolymer nanocomposites: nanoparticle anisotropy

Block copolymer melts are perfect candidates to template the position of colloidal nanoparticles in the nanoscale, on top of their well-known suitability for lithography applications. This is due to their ability to self-assemble into periodic ordered structures, in which nanoparticles can segregate depending on the polymer-particle interactions, size and shape. The resulting coassembled structure can be highly ordered as a combination of both the polymeric and colloidal properties. The time-dependent Ginzburg-Landau model for the block copolymer was combined with Brownian dynamics for nanoparticles, resulting in an efficient mesoscopic model to study the complex behaviour of block copolymer nanocomposites. This review covers recent developments of the time-dependent Ginzburg-Landau/Brownian dynamics scheme. This includes efforts to parallelise the numerical scheme and applications of the model. The validity of the model is studied by comparing simulation and experimental results for isotropic nanoparticles. Extensions to simulate nonspherical and inhomogeneous nanoparticles are discussed and simulation results are discussed. The time-dependent Ginzburg-Landau/Brownian dynamics scheme is shown to be a flexible method which can account for the relatively large system sizes required to study block copolymer nanocomposite systems, while being easily extensible to simulate nonspherical nanoparticles

Improvement in Hemodynamic Responses to Metaboreflex Activation after One Year of Training in Spinal Cord Injured Humans

Spinal cord injured (SCI) individuals show an altered hemodynamic response to metaboreflex activation due to a reduced capacity to vasoconstrict the venous and arterial vessels below the level of the lesion. Exercise training was found to enhance circulating catecholamines and to improve cardiac preload and venous tone in response to exercise in SCI subjects. Therefore, training would result in enhanced diastolic function and capacity to vasoconstrict circulation. The aim of this study was to test the hypothesis that one year of training improves hemodynamic response to metaboreflex activation in these subjects. Nine SCI individuals were enrolled and underwent a metaboreflex activation test at the beginning of the study (T0) and after one year of training (T1). Hemodynamics were assessed by impedance cardiography and echocardiography at both T0 and T1. Results show that there was an increment in cardiac output response due to metaboreflex activity at T1 as compared to T0 (545.4 ± 683.9 mL · min(-1) versus 220.5 ± 745.4 mL · min(-1), P < 0.05). Moreover, ventricular filling rate response was higher at T1 than at T0. Similarly, end-diastolic volume response was increased after training. We concluded that a period of training can successfully improve hemodynamic response to muscle metaboreflex activation in SCI subjects