2,144 research outputs found

    Name-passing calculi and crypto-primitives: A survey

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    The paper surveys the literature on high-level name-passing process calculi, and their extensions with cryptographic primitives. The survey is by no means exhaustive, for essentially two reasons. First, in trying to provide a coherent presentation of different ideas and techniques, one inevitably ends up leaving out the approaches that do not fit the intended roadmap. Secondly, the literature on the subject has been growing at very high rate over the years. As a consequence, we decided to concentrate on few papers that introduce the main ideas, in the hope that discussing them in some detail will provide sufficient insight for further reading

    SIMPLIFIED 3-D MODEL FOR THE CALCULATION OF BODY SEGMENT KINEMATIC ASYMMETRIES IN CYCLING

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    INTRODUCTION The analysis of lower limb kinematics in cycling has generally been confined in the sagittal plane by using data obtained with a 2-D analysis Furthermore, when asymmetries were evaluated this was done by detecting data from one leg at time and subsequently comparing the scores obtained from the two sides in different trials. The present work provides a three-dimensional model for the calculation of body segment kinematics, by measuring the 3-D coordinates of a reduced number of external markers. METHODS Subjects of this study were 8 professional road cyclists, (age 25.1 Ā± 40 yr., body mass: 68.6 Ā± 6.4 kg), usually covering more than 25.000 km/year The subjects used their own bicycle mounted on rollers fitted with an air-operated variable-load device. Data were recorded at three levels of external load (Iow, medium and high) The ELITE system motion analyzer was used with 4 TV cameras paired on the two sides of the cyclist. Sampling frequency was 100 Hz Size of the passive retroreflective markers was 10 mm in diameter. The 3-D body coordinates (iliac crest, great trochanter, femoral condile, malleolus, fifth metatarsal head) and some anthropometric measures of the subject were the input of a mathematical model designed to describe the spatial kinematics of seven rigid segments belonging to the lower limbs (feet, shanks, thighs and pelvis). RESULTS Tables 1 and 2 show the mean and the standard deviation of some of the variables used for the analysis They have been computed by grouping right and left patterns of the whole group As it can be seen, when the load changes there is an evident trend of some variables. For example, the range of motion decreases at the hip joint, when the load Increases, conversely it increases at the knee and at the ankle joint. The individual examination revealed as the majority of athletes were characterized by significant left-right differences in the selected lower leg angles and in some linear kinematic parameters. These asymmetries appear to be subject, joint and pedalling modality dependent. CONCLUSION The method presented here seems to be an useful tool to assess and to evaluate biomechanical data during cycling. The proposed kinematic model gives indeed a good representation of the cyclist during his action. In particular the possibility to collect simultaneously data from both sides of the body appears to be very informative about asymmetries characterizing cyclists

    Contracts for Abstract Processes in Service Composition

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    Contracts are a well-established approach for describing and analyzing behavioral aspects of web service compositions. The theory of contracts comes equipped with a notion of compatibility between clients and servers that ensures that every possible interaction between compatible clients and servers will complete successfully. It is generally agreed that real applications often require the ability of exposing just partial descriptions of their behaviors, which are usually known as abstract processes. We propose a formal characterization of abstraction as an extension of the usual symbolic bisimulation and we recover the notion of abstraction in the context of contracts.Comment: In Proceedings FIT 2010, arXiv:1101.426

    Capillary breakup and electrospinning of PA6 solutions containing FeCl3: experimental findings and correlations

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    In several applications, ranging from electronic to chemical sensing, great interest has grown for the exploitation of conducting polymer nanofibers, whose processing is, however, not straightforward, due to polymer low solubility and presence of rigid backbones. An interesting method to overcome this issue consists in the electrospinning of a spinnable polymer to obtain a template for the successive in situ polymerization of the conducting polymer monomers. Considering PANI nanofibers, a suitable template can be electrospun from PA6 solutions in formic acid containing FeCl3. In this system, the ionic salt may perturb or prevent H-bonds formation between amide groups of PA6 backbones: this could modify solution viscoelasticity, and thus affect fibres morphology. The aim of the present work is to identify the effect of FeCl3 on the solution rheological behaviour and to correlate it to electrospun fibres morphology. To this aim, solutions at several salt content underwent electrospinning and were characterized both in shear, by rotational rheometry, and extension, by capillary breakup rheometry, while fibres morphology and crystallinity were evaluated through SEM and DSC. The rheological analysis enlightens that a critical FeCl3 content exists above which the viscous component of the viscoelastic response becomes predominant. At the same concentration, the SEM observations of the electrospun fibres show the formation of severely inhomogeneous structures. A correlation between these results is proposed through the adimensional analysis of competing viscoelastic stabilization and surface tension-driven instability phenomena. Besides the aforementioned effects, the FeCl3 content affects also fibre crystallinity, as above a critical concentration fibres turn out to be completely amorphous. Interestingly, this concentration coincides with the one at which a transition is observed in the rheological behaviour

    Search for Neutron Flux Generation in a Plasma Discharge Electrolytic Cell

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    Following some recent unexpected hints of neutron production in setups like high-voltage atmospheric discharges and plasma discharges in electrolytic cells, we present a measurement of the neutron flux in a configuration similar to the latter. We use two different types of neutron detectors, poly-allyl-diglicol-carbonate (PADC, aka CR-39) tracers and Indium disks. At 95% C.L. we provide an upper limit of 1.5 neutrons cm^-2 s^-1 for the thermal neutron flux at ~5 cm from the center of the cell. Allowing for a higher energy neutron component the largest allowed flux is 64 neutrons cm^-2 s^-1. This upper limit is two orders of magnitude smaller than what previously claimed in an electrolytic cell plasma discharge experiment. Furthermore the behavior of the CR-39 is discussed to point our possible sources of spurious signals.Comment: 4 pages, 3 figure

    Arthroscopic biceps tendon tenodesis: the anchorage technical note

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    Treatment of long head biceps (LHB) tendon pathology has become an area of renewed interest and debate among orthopaedic surgeons in recent years. The background of this manuscript is a description of biceps tenodesis which ensure continual dynamic action of the tendon which depresses the head and impedes lateral translation. A new technique has been developed in order to treat LHB tendon irreversible structural abnormalities associated with cuff rotator lesions. This technique entails the construction of a biological anchor between the LHB and supraspinatus and/or infraspinatus tendons according to arthroscopic findings. The rationale, although not supported by biomechanical studies is to obtain a triple, biomechanical effect. The first of these biomechanical effects which we try to promote through the procedure of transposition is the elimination of the deviation and oblique angle which occurs as the LHB completes its intra-articular course prior to reaching the bicipital groove. Furthermore, we have found this technique extremely useful in the presence of large ruptures of the rotator cuff with muscle retraction. The most common complication associated to this particular method, observed in less than 3%, is failed biological fixation which manifests as subsidence of the tenodesis and consequent descent of the tendon with evident aesthetic deformit

    Deriving Bisimulation Congruences: 2-categories vs precategories

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    G-relative pushouts (GRPOs) have recently been proposed by the authors as a new foundation for Leifer and Milnerā€™s approach to deriving labelled bisimulation congruences from reduction systems. This paper develops the theory of GRPOs further, arguing that they provide a simple and powerful basis towards a comprehensive solution. As an example, we construct GRPOs in a category of ā€˜bunches and wirings.ā€™ We then examine the approach based on Milnerā€™s precategories and Leiferā€™s functorial reactive systems, and show that it can be recast in a much simpler way into the 2-categorical theory of GRPOs

    Chemical induction of spawning by serotonin in the ocean quahog Arctica islandica (Linne)

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    Serotonin injected into the anterior adductor muscle induced spawning in the ocean quahog Arcrica islandica (Linne) when using either individual or mass spawning techniques. This represents the fir st successful attempt to induce the release of gametes in this species which historically has been unresponsive to conventional spawning stimuli. The gametes released were competent and fertilization occurred without treating the encapsulated eggs with ammonium hydroxide or other chemicals. Larvae were reared through metamorphosis to early juvenile stage
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