Bremsstrahlung neutrinos from electron-electron scattering in a relativistic degenerate electron plasma

We present a calculation of neutrino pair bremsstrahlung due to electron-electron scattering in a relativistic degenerate plasma of electrons. Proper treatment of the in-medium photon propagator, i.e., inclusion of Debye screening of the longitudinal part and Landau damping of the transverse part, leads to a neutrino emissivity which is several orders of magnitude larger than when Debye screening is imposed for the tranverse part. Our results show that this in-medium process can compete with other sources of neutrino radiation and can, in some cases, even be the dominant neutrino emission mechanism. We also discuss the natural extension to quark-quark bremsstrahlung in gapped and ungapped quark matter.Comment: 15 pages, 7 figure

INVESTIGATING THE METABOLIC PROFILE OF RUN-UP RACES AND THE MECHANICS OF WOBBLING VISCERAL MASS IN VERTICAL JUMPS.

This Thesis is organized in two parts based on two different investigations about human motion: the metabolic and mechanical analysis of \u2018skyscraper running\u2019, and the estimation of the visceral mass displacement in vertical jumps. Skyscraper running is a novel sport activity, in which the athletes run on emergency stairs of the tallest building of the world, during the \u2018run up\u2019 races of the world championship circuit. In PART I of this Thesis, this topic has been analysed in terms of mechanical and metabolic requirements, both at general and individual level. Skyscraper runners\u2019metabolic profile, has been inferred from the total mechanical power estimated in 36 world records (48-421 m tall buildings), ranked by gender and age range. Individual athlete\u2019s performance (n=13) has been experimentally investigated during the Pirelli Vertical Sprint, with data loggers for altitude and heart rate. At a general level, a non-linear regression of Wilkie\u2019s model relating maximal mechanical power to event duration, revealed the gender and age differences in term of maximum aerobic power and anaerobic energy resources particularly needed at the beginning of the race. The total mechanical power was found to be partitioned among: the fraction devolved to raise the body centre of mass: W\u2d9 STA.EXT = 80.4 \ub1 2.9%, the need to accelerate the limbs with respect to the body: W\u2d9 STA.INT = 4.5 \ub1 2.1%, and running in turns between flights of stairs: W\u2d9 TUR =15.1 \ub1 2.0%. At the individual level, experiments revealed that these athletes show a metabolic profile similar to middle-distance runners. Furthermore, best skyscraper runners keep constant vertical speed and heart rate throughout the race, while others suddenly decelerate, negatively affecting the race performance. In PART II of this Thesis another interesting study has been discussed: the mechanics of visceral mass motion in vertical jumps. This internal mass motion could occur in all the locomotion paradigms, and also in all the movements characterized by a high centre of mass vertical displacement. Moreover, visceral mass shows significant couplings with the respiratory system, as has been discussed in the past in famous studies on quadruped locomotion. Here viscera motion has been analyzed in a simple and well know motor task as the vertical jump, focusing on the effect of respiratory and muscle contractions strategies to limit its displacement, and to improve trunk-pelvis segment stiffness. A validated method for the estimation of visceral mass displacement has been applied during jump sequences with two different techniques: six subjects before and after a specific training period, executed the natural jump and the \u201ccontrolled\u201d jump sessions. In that method, the simultaneous measurement of ground reaction forces and spatial coordinates allow the estimation of the relative movement between the \u2018invisible\u2019 abdomen content and the \u2018container\u2019, i.e. the rest of the body as described by the position of external markers. The results show a significantly higher (p < 0.05 \u2013 paired t-test) mean of visceral mass displacement (Total = 0.087 \ub1 s.d. 0.021 m) of all the subjects, in normal jumps, compared to the mean of visceral mass displacement (Total = 0.070 \ub1 s.d. 0.027 m) in controlled jumps. An analysis of variance (ANOVA 2-ways) shows a significant effect of jump technique but also of subject and jump-subject interaction, confirming an elevated variability between the subjects. A intraclass-correlation exhibit a significant pattern (ICC= 0.791; p = 0.017) and in 5 of 6 subjects, there is a higher mean nominal value of VMD in normal jumps. Also pectorals and low abdominal fat displacements has been measured, showing mean values (weighted by a scaling factor) of 4.5 710-4 m and 8.9 710-4 m in normal jumps, and 4.5 710-4 m and 9.6 710-4 m in controlled jumps respectively. A quantitative and qualitative analysis on visceral mass displacement curve has been completed for both the jumping techniques: a comparison with the \u2018periodic\u2019 curve of body centre of mass show a constant delay (\u2018phase shift\u2019) with a mean value of 18.1 \ub1 s.d. 5.73 ms during the aerial phase and 18.8 \ub1 s.d. 9.8 ms in the landing phase. Finally a preliminary estimation of the internal mass vibration parameters has been showed: the mean values and s.d. of the stiffness in normal and controlled jumps are k1= 18.2 \ub1 13.5 KN/m and k2= 17.9 \ub1 12.1 KN/m respectively, while the damping constant mean values and s.d. are c1 300.3 \ub1 170.7 N/(m/s) is and c2 is 287.3 \ub1 129.8 N/(m/s). For the first time, a method for the estimation of visceral mass displacement, useful in biomechanics and in locomotion-respiratory coupling investigations, has been used in an applied condition. The effects of the \u201ccontrolled\u201d jumping techniques using respiration and muscles contraction strategies to limit viscera displacement has been demonstrated. The displacement of visceral mass and the body frame have been quantified and compared, and a preliminary estimation of vibration parameter of the internal system has been showed. We foresee an increasing interest in sports biomechanics to improve athletes jumping performance, as well as in the energetics and biomechanics of locomotion

A modelling language for the effective design of Java annotations

This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in SAC '15 Proceedings of the 30th Annual ACM Symposium on Applied Computing, http://dx.doi.org/10.1145/2695664.2695717.This paper describes a new modelling language for the ef- fective design of Java annotations. Since their inclusion in the 5th edition of Java, annotations have grown from a use- ful tool for the addition of meta-data to play a central role in many popular software projects. Usually they are con- ceived as sets with dependency and integrity constraints within them; however, the native support provided by Java for expressing this design is very limited. To overcome its de ciencies and make explicit the rich conceptual model which lies behind a set of annotations, we propose a domain-speci c modelling language. The proposal has been implemented as an Eclipse plug- in, including an editor and an integrated code generator that synthesises annotation processors. The language has been tested using a real set of annotations from the Java Per- sistence API (JPA). It has proven to cover a greater scope with respect to other related work in di erent shared areas of application.This work was supported by the Spanish Ministry of Economy and Competitivity with project Go-Lite (TIN2011-24139) and the Community of Madrid with project SICOMORO (S2013/ICE-3006)

Cervical spine injuries: A whole-body musculoskeletal model for the analysis of spinal loading

This is the final version of the article. Available from Public Library of Science via the DOI in this record.Cervical spine trauma from sport or traffic collisions can have devastating consequences for individuals and a high societal cost. The precise mechanisms of such injuries are still unknown as investigation is hampered by the difficulty in experimentally replicating the conditions under which these injuries occur. We harness the benefits of computer simulation to report on the creation and validation of i) a generic musculoskeletal model (MASI) for the analyses of cervical spine loading in healthy subjects, and ii) a population-specific version of the model (Rugby Model), for investigating cervical spine injury mechanisms during rugby activities. The musculoskeletal models were created in OpenSim, and validated against in vivo data of a healthy subject and a rugby player performing neck and upper limb movements. The novel aspects of the Rugby Model comprise i) population-specific inertial properties and muscle parameters representing rugby forward players, and ii) a custom scapula-clavicular joint that allows the application of multiple external loads. We confirm the utility of the developed generic and population-specific models via verification steps and validation of kinematics, joint moments and neuromuscular activations during rugby scrummaging and neck functional movements, which achieve results comparable with in vivoand in vitrodata. The Rugby Model was validated and used for the first time to provide insight into anatomical loading and cervical spine injury mechanisms related to rugby, whilst the MASI introduces a new computational tool to allow investigation of spinal injuries arising from other sporting activities, transport, and ergonomic applications. The models used in this study are freely available at simtk.org and allow to integrate in silico analyses with experimental approaches in injury prevention.Funding: This project is funded by the Rugby Football Union (RFU) Injured Players Foundation. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Musculoskeletal modelling of the human cervical spine for the investigation of injury mechanisms during axial impacts

This is the final version. Available from Public Library of Science via the DOI in this record.All relevant data are available at Figshare [https://figshare.com/projects/SILVESTROS_PLOS_ONE_SUPPORTING_DOCUMENTS/58280] and musculoskeletal models and relevant project information is available on the OpenSim SimTK repository [https://simtk.org/projects/csibath].Head collisions in sport can result in catastrophic injuries to the cervical spine. Musculoskeletal modelling can help analyse the relationship between motion, external forces and internal loads that lead to injury. However, impact specific musculoskeletal models are lacking as current viscoelastic values used to describe cervical spine joint dynamics have been obtained from unrepresentative quasi-static or static experiments. The aim of this study was to develop and validate a cervical spine musculoskeletal model for use in axial impacts. Cervical spine specimens (C2-C6) were tested under measured sub-catastrophic loads and the resulting 3D motion of the vertebrae was measured. Specimen specific musculoskeletal models were then created and used to estimate the axial and shear viscoelastic (stiffness and damping) properties of the joints through an optimisation algorithm that minimised tracking errors between measured and simulated kinematics. A five-fold cross validation and a Monte Carlo sensitivity analysis were conducted to assess the performance of the newly estimated parameters. The impact-specific parameters were integrated in a population specific musculoskeletal model and used to assess cervical spine loads measured from Rugby union impacts compared to available models. Results of the optimisation showed a larger increase of axial joint stiffness compared to axial damping and shear viscoelastic parameters for all models. The sensitivity analysis revealed that lower values of axial stiffness and shear damping reduced the models performance considerably compared to other degrees of freedom. The impact-specific parameters integrated in the population specific model estimated more appropriate joint displacements for axial head impacts compared to available models and are therefore more suited for injury mechanism analysis.Rugby Football Union (RFU) Injured Players Foundatio

Analysis of cervical spine loading in rugby scrummaging: a computer simulation approach

Musculoskeletal modelling is widely used in biomechanics for the analysis and simulation of human motion. A modelling approach allows estimates of the internal load on specific anatomical structures, and the individual muscle forces that govern movement execution. Within the analysis of impact events in rugby union, modelling can help the understanding of the mechanisms of acute and chronic cervical spine injuries, starting from experimental measures of external load on the player, and progressing to the estimation of stresses acting on the internal cervical structures. During this part of the applied session, we will use a novel musculoskeletal model and previously collected experimental data (forces and kinematics) to analyse the cervical spine loading experienced during a rugby scrum. An open-source biomechanical software (OpenSim 3.2) will be used to set up and run inverse and forward dynamics pipelines to calculate joint moments and joint reaction forces, and to analyse “what if…” scenarios

Measuring impacts and informing modelling processes

Primarily using rugby union situations as case study examples for the practical demonstration, the initial part of the session will discuss both familiar and emerging techniques to measure the biomechanics of sport impact situations. We will cover some of the issues that need to be accounted for to acquire robust data in such complex environments, and we will discuss how experimental measures can be either used in their own right to develop knowledge of impact biomechanics or can provide data to input a modelling pipeline and for model validation purposes

Freely annotating C#

Reflective programming is becoming popular due to the increasing set of dynamic services provided by execution environments like JVM and CLR. With custom attributes Microsoft introduced an extensible model of reflection for CLR: they can be used as additional decorations on element declarations. The same notion has been introduced in Java 1.5. The annotation model, both in Java and in C#, limits annotations to classes and class members. In this paper we describe [a]C#a, an extension of the C# programming language, that allows programmers to annotate statements and code blocks and retrieve these annotations at run-time. We show how this extension can be reduced to the existing model. A set of operations on annotated code blocks to retrieve annotations and manipulate bytecode is introduced. We also discuss how to use [a]C# to annotate programs giving hints on how to parallelize a sequential method and how it can be implemented by means of the abstractions provided by the run-time of the language. Finally, we show how our model for custom attributes has been realized

Hyperferritinemia without iron overload in patients with bilateral cataracts: a case series

Hepatologists and internists often encounter patients with unexplained high serum ferritin concentration. After exclusion of hereditary hemochromatosis and hemosiderosis, rare disorders like hereditary hyperferritinemia cataract syndrome should be considered in the differential diagnosis. This autosomal dominant syndrome, that typically presents with juvenile bilateral cataracts, was first described in 1995 and has an increasing number of recognized molecular defects within a regulatory region of the L-ferritin gene (FTL). CASE PRESENTATION: Two patients (32 and 49-year-old Caucasian men) from our ambulatory clinic were suspected as having this syndrome and a genetic analysis was performed. In both patients, sequencing of the FTL 5' region showed previously described mutations within the iron responsive element (FTL c.33 C > A and FTL c.32G > C). CONCLUSION: Hereditary hyperferritinemia cataract syndrome should be considered in all patients with unexplained hyperferritinemia without signs of iron overload, particularly those with juvenile bilateral cataracts. Liver biopsy and phlebotomy should be avoided in this disorder