Quantum Monte Carlo study of a vortex in superfluid 4^4He and search for a vortex state in the solid

We have performed a microscopic study of a straight quantized vortex line in three dimensions in condensed $^4$He at zero temperature using the Shadow Path Integral Ground State method and the fixed-phase approximation. We have characterized the energy and the local density profile around the vortex axis in superfluid $^4$He at several densities, ranging from below the equilibrium density up to the overpressurized regime. For the Onsager-Feynman (OF) phase our results are exact and represent a benchmark for other theories. The inclusion of backflow correlations in the phase improves the description of the vortex with respect to the OF phase by a large reduction of the core energy of the topological excitation. At all densities the phase with backflow induces a partial filling of the vortex core and this filling slightly increases with density. The core size slightly decreases for increasing density and the density profile has well defined density dependent oscillations whose wave vector is closer to the wave vector of the main peak in the static density response function rather than to the roton wave vector. Our results can be applied to vortex rings of large radius $R$ and we find good agreement with the experimental value of the energy as function of $R$ without any free parameter. We have studied also $^4$He above the melting density in the solid phase using the same functional form for the phase as in the liquid. We found that off-diagonal properties of the solid are not qualitatively affected by the velocity field induced by the vortex phase, both with and without backflow correlations. Therefore we find evidence that a perfect $^4$He crystal is not a marginally stable quantum solid in which rotation would be able to induce off-diagonal long-range coherence.Comment: 15 pages, 8 figure

Towards a Formal Semantics for UML/MARTE State Machines Based on Hierarchical Timed Automata

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Avant-propos : « obscenae sunt aves, quae canendo adversa significant »

obscenae sunt aves, quae canendo adversa significant Le fantasme de l’assouvissement du désir habite une région inconnue du sujet, perpétue l’impossible, invente un lieu secret, murmure ses vœux en se cachant derrière une érotique qui est tout d’abord une éthique du dire. Cette sublimation du langage entraîne, bien évidemment, toute une vaste gamme de parodies et de contre-textes grivois. Le bonheur furtif est alors livré à l’exposition publique, honni, bafoué par une langue médisante qui veu..

Avant-propos : « obscenae sunt aves, quae canendo adversa significant »

obscenae sunt aves, quae canendo adversa significant Le fantasme de l’assouvissement du désir habite une région inconnue du sujet, perpétue l’impossible, invente un lieu secret, murmure ses vœux en se cachant derrière une érotique qui est tout d’abord une éthique du dire. Cette sublimation du langage entraîne, bien évidemment, toute une vaste gamme de parodies et de contre-textes grivois. Le bonheur furtif est alors livré à l’exposition publique, honni, bafoué par une langue médisante qui veu..

Flexible Modular Formalization of UML Sequence Diagrams

UML Sequence Diagrams are one of the most commonly used type of UML diagrams in practice. Their semantics is often considered to be straightforward, but a more detailed analysis reveals diverse interpretations. These different choices must be properly supported by verification tools. This paper describes a formal framework for capturing semantic choices in a precise and modular way. The user is then able to select the semantics of interest, mix different interpretations, and analyze diagrams according to the chosen solution. This solution is supported by Corretto, our UML verification environment, to allow the user to play with different semantics and prove properties on Sequence Diagrams, accordingly

How bit-vector logic can help improve the verification of LTL specifications over infinite domains

Propositional Linear Temporal Logic (LTL) is well-suited for describing properties of timed systems in which data belong to finite domains. However, when one needs to capture infinite domains, as is typically the case in software systems, extensions of LTL are better suited to be used as specification languages. Constraint LTL (CLTL) and its variant CLTL-over-clocks (CLTLoc) are examples of such extensions; both logics are decidable, and so-called bounded decision procedures based on Satisfiability Modulo Theories (SMT) solving techniques have been implemented for them. In this paper we adapt a previously-introduced bounded decision procedure for LTL based on Bit-Vector Logic to deal with the infinite domains that are typical of CLTL and CLTLoc. We report on a thorough experimental comparison, which was carried out between the existing tool and the new, Bit-Vector Logic-based one, and we show how the latter outperforms the former in the vast majority of cases

Efeitos do treinamento de equilíbrio baseado em pertubação sobre o controle neuromuscular reativo de idosas ativas da comunidade

Orientadora : Profª. Drª. Anna Raquel Silveira GomesTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Educação Física. Defesa: Curitiba, 30/08/2013Inclui referênciasÁrea de concentraçao: Exercício e esporteResumo: Após perturbações inesperadas (i.e. tropeço ou escorregão), a capacidade de readequar o controle postural está notadamente diminuída em idosos, devido a deficiências cumulativas relacionadas ao envelhecimento, podendo acarretar aumento da incidência de quedas. Devido a isto, são necessárias intervenções que ajam sobre o controle postural de idosos com a finalidade de aumentar a capacidade de recuperação do equilíbrio frente a essas perturbações. Dessa forma, o objetivo desse estudo foi avaliar os efeitos do treinamento de equilíbrio e destreinamento, sobre o controle postural reativo de idosas da comunidade, por meio de um teste de perturbação abrupta. Trata-se de um ensaio clínico controlado e randomizado, no qual participaram idosas ativas, saudáveis, não institucionalizadas (n=41), que foram divididas em 2 grupos: grupo exercício (GE, n=21, 67,0 ± 2,0 anos) que realizou o treinamento de equilíbrio, 3 vezes por semana, durante 6 semanas e grupo controle (GC, n=20, 67,9 ± 3,1 anos) que participou de palestras sobre prevenção de quedas e hábitos de vida saudáveis. O protocolo de exercícios utilizado foi composto por um circuito de seis dispositivos instáveis, sendo eles: disco proprioceptivo, balancim, Bosu®, Bosu invertido® prancha de equilíbrio e mini-trampolim. Foram realizadas 4 repetições de 1 minuto de duração em cada dispositivo. A amplitude de deslocamento do centro de pressão (CP) e a atividade eletromiográfica (EMG) (tempo de reação muscular, tempo ao pico de ativação EMG e amplitude EMG (0-200, 201-400 e 401-600ms) dos músculos reto femoral (RF), vasto medial oblíquo (VMO), tibial anterior (TA), semitendinoso (ST), gastrocnêmio medial (GM) e sóleo (SO) foram avaliados durante um teste de perturbação abrupta nos sentidos anteroposterior e posteroanterior. A falha de ativação central (CAR) dos músculos dorsiflexores e flexores plantares de tornozelo e o tempo do teste de mobilidade funcional Timed Up & Go Test (TUG) também foram avaliados. Todas as variáveis foram analisadas antes, imediatamente após o treinamento e 6 semanas após o treinamento (destreinamento). A ANOVA mista, ANOVA one-way e ANOVA de medidas repetidas foi usada para comparar as variáveis paramétricas e a ANOVA de Friedman e o teste U de Mann Whitney foram usados para comparação das variáveis não paramétricas. Os resultados mostraram, somente para o grupo exercício, redução do deslocamento do centro de pressão anteroposterior (pré 14,91±2,11cm; pós 13,58±2,37cm), redução do tempo de reação dos músculos TA (pré 94,00±11,22ms; pós 88,19±14,52ms), GM (pré 101,33±11,78ms; pós 94,19±14,21ms) e SO (pré 92,00±12,16ms; pós 84,66±14,48ms) e redução do tempo ao pico EMG dos músculos TA (pré 144,71±23,73ms; pós 127,71±20,21ms) e GM (pré 128,52±14,65ms; pós 111,71±13,55ms), (p<0,05). Foi encontrado aumento da amplitude da atividade eletromiográfica nos músculos TA (pré 150,04±32,61?V; pós 166,85±30,06?V), GM (pré 74,57±18,83?V; pós 87,52±16,24?V) e SO (pré 66,90±20,25?V; pós 84,47±16,13?V) na fase inicial (0-200ms) e no músculo SO (pré 40,00±12,91?V; pós 49,90±19,99?V) na fase intermediária (201-400ms) após o teste de perturbação (p<0,05). Houve redução do tempo de execução do TUG (pré 10,19±1,31s; pós 9,46±1,24s) no GE e aumento da relação de ativação central (CAR) nos músculos dorsiflexores (pré 0,871±0,02; pós 0,891±0,02) e flexores plantares de tornozelo (pré 0,875±0,02; pós 0,896±0,02) após o treinamento de equilíbrio (p<0,05). Após o período de destreinamento, apenas o músculo TA manteve seu ganho no tempo de reação muscular (pós 88,19±14,52?V; pós6 89,23±13,94?V) e tempo ao pico EMG (pré 127,71±20,21; pós 130,09±17,08) (p<0,05). O protocolo de treinamento de equilíbrio proposto aumentou a capacidade muscular reativa, o nível de ativação muscular e o controle postural em idosas ativas da comunidade. Porém, essa melhora não foi mantida após o período de destreinamento para a maioria das variáveis.Abstract: After unpredictable perturbation (i.e. trip and slip), the ability to readjust the postural control is notably decreased in the elderly, due to aging-related cumulative impairments which may lead to increased incidence of falls. For this reason interventions focused on the postural control of the elderly with the purpose to increase the capability of recovering balance against this perturbation and to prevent falls are necessary. In this way, the aim of this study was to evaluate the effects of a balance training on community-dwelling older women reactive postural control, by means of an abrupt perturbation test and the remain effect after a detraining period. It is a randomized controlled trial, involving active, not institutionalized, healthy elderly women, (n = 46), which were divided into 2 groups: exercise group (EG, n = 23, 67.0 ± 2.0 years) that held the balance training 3 times a week for 6 weeks and the control group (CG, n = 23, 67.9 ± 3.1 years) who participated in lectures on prevention of falls and healthy lifestyle habits. The exercise protocol used included six unstable devices for balance training as proprioceptive disk, rocker, Bosu®, inverted Bosu® balance board and mini-trampoline. Four repetitions of 1 minute duration each were performed in each device. The amplitude of displacement of center of pressure (CP) and the electromyography (EMG) activity (muscle reaction time, time to peak EMG and EMG amplitude (0-200, 201-400 and 401-600ms) of rectus femoris (RF), vastus medialis oblique (VMO), tibialis anterior (TA), semitendinous (ST), medial gastrocnemius (MG) and soleus (SO) muscles were evaluated during an unpredictable perturbation test in both anteroposterior and posteroanterior directions. The central activation failure (CAR) of ankle dorsiflexor and plantar flexor muscles and the time of functional mobility Timed Up & Go Test (TUG) were also evaluated. All variables were analyzed at baseline, immediately after training and 6 weeks after training (detraining). The mixed-model ANOVA, One-way ANOVA and Repeated measures ANOVA were used to compare outcomes with a normal distribution, while non-parametric data were analyzed by Friedman ANOVA and U Mann Whitney test. The main results showed, only for the group exercise, reduced anteroposterior displacement of the center of the pressure (pre 14.91±2.11cm; post 13.58±2.37cm), reduced TA muscle reaction time (pre 94.00±11.22ms; post 88.19±14.52ms), MG (pre 101.33±11.78ms; post 94.19±14.21ms) and SO (pre 92.00±12.16ms; post 84.66±14.48ms), reduced the time to peak EMG of TA muscle (pre 144.71±23.73ms; post 127.71±20.21ms) and MG muscle (pre 128.52±14.65ms; post 111.71±13.55ms) (p<0.05). Electromyography activity increase was found in muscles TA (pre 150.04±32.61?V; post 166.85±30.06?V), MG (pre 74.57±18.83?V; post 87.52±16.24?V) and SO (pre 66.90±20.25?V; post 84.47±16.13?V) in the early phase (0-200ms) after the perturbation test and the muscle SO showed an increase (pre 40.00±12.91?V; post 49.90±19.99?V) in intermediate phase (201-400ms) (p<0.05). Functional mobility was also improved as shown by a decrease (pre 10.19±1.31s; post 9.46±1.24s) in time to execute the test after training (p<0.05). At last there was an increase of central activation ratio (CAR) in dorsiflexor (pre 0.871±0.02; post 0.891±0.02) and plantar flexor muscles (pre 0.875±0.02; post 0.896±0.02) of the ankle after the balance training (p<0.05). After the detraining period, only the TA muscle sustained the gain in muscle reaction time (post 88.19±14.52?V; post6 89.23±13.94?V) and time to peak EMG (pre 127.71±20.21; post 130.09±17.08) (p<0.05). The balance training protocol proposed increased the reactive muscle capacity, increased the level of muscle activation, postural control and functional mobility in active community elderly women. However, this improvement was not maintained after the detraining period for most variables

Natural hybridization and introgression between the Long-Spurred orchid, <i>Orchis longicornu</i> Poiret and the Green-Winged orchid, <i>O. morio</i> L. (Orchidaceae) in Corsica

Genetic studies have revealed in Southern Corsica, near Bonifacio, not only the existence of sporadic F1 hybrids between Orchis longicornu Poiret and O. morio L., but of a hybrid zone where both parental taxa are more or less introgressed. Our data indicate complete interfertility between the two taxa, which should therefore be considered as subspecies of the same biological species

<i>Orchis longicornu</i> Poiret in Sardinia: genetic, morphological and chorological data

Data are given on the genetic structure, morphology and chorology of the Long-Spurred orchid, Orchis longicornu Poiret (1789) from Sardinia and the occurrence in this island of the morphologically similar Orchis morio L. (1753), often recorded for Sardinia, is investigated. The genetic analysis of 27 enzyme lo ci in population samples from locations where both species had been recorded showed that: (i) in the population samples from Sardinia the polymorphic loci are in Hardy-Weinberg equilibrium; (ii) these samples are genetically poorly differentiated from each other (average Nei's D = 0.01): less than 2% of the overall genetic variation observed is attributable to differences between populations (GST = 0.015); (iii) a high rate of gene flow was estimated between Sardinian populations: Nm ≈ 4, possibly owing to seed dispersal by wind; (iv) when Sardinian samples are compared with O. morio from continental Italy, significant differences in genetic variation were observed: average He = 0.16 in the former, 0.12 in thc latter; (v) the genetic distance found between Sardinian populations and those of O. morio from continental ltaly is relatively high: average Nei's D = 0.18, average Rogers' D = 0.22; (vi) highly significant differences in allele frequencies were found at a number of loci (Mdh-2, Sod-3, Pgm-1, Gpi-1, Gpi-2) between populations from Sardinia and continental Italy, each giving a probability of correct identification that varies from 0.90 to 1 (diagnostic loci). These findings provide evidence that O. morio is not present in the material genetically analyzed from Sardinia, which includes a single species, apparently corresponding to O. longicornu. The slight heterogeneity observed at some loci in the Sardinian population samples can be attributed in some cases (e.g. Mdh-1, Adh, Est-6) to local differences, possibly adaptive; in others (e.g. Pgm-1 and Gpi-l) to genetic drift effects. The hypothesis that some alleles (Gpi-1100, Dia107, NADHdh-296) found in O. morio and recorded at low frequency in a few Sardinian populations reflect palaeointrogressive phenomena (owing to sporadical immigrant individuals of O. morio having diluted their genes in O. longicornu genome through multiple generations of backcrosses) is not sufficiently supported by the available data. The genetic data are in agreement with the results from morphological studies. These involved the examination of about 1500 specimens (both alive and dried) from all over Sardinia, and their comparison with herbarium specimens of O. longicornu from patria typica (Algeria) and of O. morio from continental Italy. The typification of O. longicornu is given. The specimens from Sardinia correspond well, on a morphological basis, to the Algerian ones and therefore were all assigned to O. longicornu. Several characters were considered, differentiating O. longicornu from O. morio both in fresh and dried specimens. However, some of them, currently used in diagnostic keys, show much overlap between the two species. This explains the quotations of O. morio from Sardinia, that appear to be misidentifications of O. longicornu. A description of O. longicornu from Sardinia is provided, and its distribution in the island is defined, on the basis of (i) a critical revision of literature rccords, and (ii) the examination of fresh and dried Sardinian specimens. O. longicornu is shown to be widespread throughout Sardinia, living in many different habitats from 0 to 1500 m a.s.l