Physical Frame Research Articles

Physical Activity Message Framing and Ethnicity Before and During COVID-19

ABSTRACT People of Black ethnicities are well known to be disproportionately burdened by coronavirus and have poorer health outcomes. Public health messages encouraged physical activity during the pandemic as it is evidenced to positively affect the immune system, however people of Black ethnicities are often reported as failing to achieve the recommended daily amount. Health message framing during COVID-19 specifically in relation to ethnicity and physical activity motivation has yet to be investigated. Two studies examined message frame effect on physical activity motivation prior to and at the onset of the pandemic and how this differed by ethnicity. Gain framed messages were found to positively affect physical activity motivation pre-COVID-19 and during the pandemic fear framed messages were found to positively affect physical activity motivation. Neither of these effects differed by ethnicity. Implications for future physical activity health message framing are discussed.

Improving stakeholder participation in schools: Intentionally inviting practices of school heads in Cape Coast and Ajumako school districts, Ghana

A sequential mixed-method design adopting a non-experimental survey and a basic interpretive study was used to explore the intentionally inviting practices of school heads of the Cape Coast metropolis and Ajumako district. Data were collected using 2 X 2 Intentionally-Inviting Matrix and semi-structured interview protocols.
 Data collected from the survey were analysed using frequency counts, while the data from the interview were analyzed and put into themes that provided a description on how the adopted practices promote stakeholder participation. The study findings revealed that school heads in Cape Coast metropolis and Ajumako district adopt intentionally inviting practices that address the physical frame of the school, communication with stakeholders, and building relationship with stakeholders to promote stakeholder involvement in schools. The study further revealed that the adopted practices of the school heads foster a sense of pride in the stakeholders to be connected to the school. The practices also increase stakeholder confidence and trust in the school head. The Ghana Education Service should replicate the study in other school districts to identify the practices that support stakeholder participation in schools and also conduct a similar study to elicit the perceptions of stakeholders on practices that enhance their participation in schools.
 
 

Radio Frequency Fingerprint-Based DSRC Intelligent Vehicle Networking Identification Mechanism in High Mobility Environment

In recent years, Dedicated Short-Range Communication (DSRC) vehicle interconnection technology has achieved mature development and broad applications, which is the key Vehicle to Everything (V2X) technology to realize transport intelligence. However, the openness of wireless transmission and the mobility of wireless terminals cause the identification mechanism of the DSRC system to face serious security threats. A radio frequency fingerprint (RFF)-based identification method can better resist the identity attack and spoofing by extracting the hardware characteristics formed by the differences of electronic components to authenticate different devices. Therefore, in this paper a novel RFF identification mechanism is proposed for IEEE 802.11p protocol-based DSRC intelligent vehicle networking devices suitable for a high mobility environment, in which the preamble field features of physical layer frames are extracted as device fingerprints, and the random forest algorithm and sequential detection method are used to distinguish and authenticate different devices. The experiment and simulation results demonstrate that the identification accuracy rates of the eight DSRC modules in the low-speed LOS and NLOS experimental states and up to 70 km/h high-speed simulations all exceed 99%, illustrating that this method has important application value in the field of identity authentication of V2X devices in high-speed scenarios.

Analysis of coupling effects on hydraulic controlled 6 degrees of freedom parallel manipulator

This paper presents an analysis of the coupling effects between degrees of freedom of a hydraulic controlled six DOF parallel manipulator. Based on the singular value decomposition to the properties of its joint space inverse mass matrix, the method is put forward to analyze coupling effects between degrees of freedom using a transformation matrix, the product of transposed Jabobian matrix and an orthogonal unitary matrix, of which each element represents decoupled modal space coordinates with respect to physical task space frame. The simulation results in frequency domain prove the theoretical analysis right. The analysis will provide useful information to mechanism and controller designer, to asses from concept the coupling effects between DOF in respect of the requirement for a particular application and also for the study on decoupling control strategies.

Relational observables in asymptotically safe gravity

We introduce an approach to compute the renormalisation group flow of relational observables in quantum gravity which evolve from their microscopic expressions towards the full quantum expectation value. This is achieved by using the composite operator formalism of the functional renormalisation group. These methods can be applied to a large class of relational observables within a derivative expansion for different physical coordinate systems. As a first application we consider four scalar fields coupled to gravity to represent the physical coordinate frame from which relational observables can be constructed. At leading order of the derivative expansion the observables are the inverse relational metric and the relational scalar curvature. We evaluate their scaling dimensions at the fixed point, both in the standard renormalisation group scheme and in the essential scheme. This represents the first steps to describe running observables within asymptotic safety; this treatment can be generalised to other observables constructed from different tensors and in different physical coordinate systems.

Digitised Justice: The New Two Tiers?

Prevailing conditions of access to justice and due process in the Singapore courts are criticised through McBarnet’s two-tier lens and Carlen’s dramaturgical understandings of criminal court realities. More than an interest in the structural separation of the Singapore judiciary, the paper interrogates the dualism between the imagined workings of justice and the daily operational experience for users of the Singapore courts. The scene is set to understand ideologies of triviality and irrelevance and their impact on justice service delivery in subordinate courts where legal representation and offender participation are the exception. To speculate on novel influences of triviality and irrelevance through machine-learned automation, an audit of Singapore’s present-day court technologies and its increasingly digitised court processes and format is detailed in the second part. The administrative benefits of digitisation notwithstanding, the paper reasons that digitalisation motivated by convenience, cost-cutting and emergency exigencies presents additional dangers to justice access and due process delivery above those already at play. These further challenges are deciphered through considerations of how justice service delivery is depersonalised and routinised in disruptive digital models. Digitized justice suggests a new ‘two tiers’ duality between physical and virtual frames of service delivery and contestation. The ‘on-line’ screen shifts the theatre from the courtroom to the ‘zoom room’. This exploration of two tiers of justice and theatre of the courtroom re-imagined through digitisation offers the opportunity to appreciate and activate automated decision processes and data management as part of the solution, rather than conceding their exacerbation of the ‘injustice’ posed by this two tiers ideology and courtroom drama exclusionism.

Capillary imbibition depth in particle-bed 3D printing – Physical frame and one-dimensional experiments

This paper deals with the control of the net geometry of a printed object in the case of powder-bed or particle bed binding technologies. We first measure and compare water penetration in one-dimensional experiments for various powder-beds. Our results, despite the simplicity of the experimental set-up, show a feature that has not been reported in literature so far, namely the fact that water penetration depth is not finite but is fully uncontrolled on longer time scales. We discuss the physical origin of this feature and the reasons why it is hidden by other aspects in most papers or applications. We finally show that water penetration depth can be controlled by a dispersed organic water thickener. Our results suggest the formation of a non-Newtonian fluid between the binder grains, which allows, in turn, for the control of the naturally uncontrolled capillary-driven water penetration in the powder-bed.

Scalar-tensor cosmologies in a minisuperspace formulation: A case study

We revisit a general minisuperspace (MSS) formalism for scalar tensor Friedmann-Lema\^{\i}tre-Robertson-Walker type cosmological models in an arbitrary frame with a perfect fluid source. We discuss how to impose Cauchy data on the corresponding dynamical system in order to reconstruct a standard ($\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$) cosmological model. So far, the integrability of such models has been extensively studied in the Einstein or Jordan frames mainly. We extend these studies to an arbitrary frame taking into account nonminimal coupling between matter and gravity. To this aim we explore a gauge freedom associated with a choice of lapse function. We show that particular isothermal MSS coordinates are related with Einstein frames representing solution equivalent classes and have some invariant meaning. This provides a new universal framework for investigating cosmic evolution in an arbitrary frame: analytical solutions obtained in the Einstein frame can be transformed back to the physical frame by making use of a conformal transformation and field redefinition. We also show how such a technique can be useful when applied to Wheeler-DeWitt quantum cosmology.

Massless fermions in spatially flat FLRW space-times

The propagation of the packets of left-handed plane wave solutions of the massless Dirac equation is studied in spatially flat Friedmann–Lemaître–Robertson–Walker (FLRW) space-times. Assuming that the observations are performed in physical frames with Painlevé–Gullstrand coordinates, the current and energy–momentum tensor are derived, emphasising their severe decay and moderate dispersion during propagation. As the wave packets move along null geodesics, interesting effects are produced by the apparent or event horizons.

On Thermal Energy Transport Complications in Chemically Reactive Liquidized Flow Fields Manifested with Thermal Slip Arrangements

Heat transfer systems for chemical processes must be designed to be as efficient as possible. As heat transfer is such an energy-intensive stage in many chemical processes, failing to focus on efficiency can push up costs unnecessarily. Many problems involving heat transfer in the presence of a chemically reactive species in the domain of the physical sciences are still unsolved because of their complex mathematical formulations. The same is the case for heat transfer in chemically reactive magnetized Tangent hyperbolic liquids equipped above the permeable domain. Therefore, in this work, a classical remedy for such types of problems is offered by performing Lie symmetry analysis. In particular, non-Newtonian Tangent hyperbolic fluid is considered in three different physical frames, namely, (i) chemically reactive and non-reactive fluids, (ii) magnetized and non-magnetized fluids, and (iii) porous and non-porous media. Heat generation, heat absorption, velocity, and temperature slips are further considered to strengthen the problem statement. A mathematical model is constructed for the flow regime, and by using Lie symmetry analysis, an invariant group of transformations is constructed. The order of flow equations is dropped down by symmetry transformations and later solved by a shooting algorithm. Interesting physical quantities on porous surfaces are critically debated. It is believed that the problem analysis carried out in this work will help researchers to extend such ideas to other unsolved problems in the field of heat-transfer fluid science.

Supplemental Material for Beyond the Body/Self-Consciousness Matrix: Scale of the Physical Frame of Reference and Self-Transcendence Experience

Supplemental Material for Beyond the Body/Self-Consciousness Matrix: Scale of the Physical Frame of Reference and Self-Transcendence Experience

On‐field test campaign performance of VDE‐SAT Link ID 20 over Norsat‐2 LEO satellite

SummaryThe latest technical recommendation by the International Telecommunication Union (ITU) for a data exchange system in the VHF maritime mobile band defines a random access channel (RAC) for communications on the uplink channel between vessels and satellites. The physical layer frame for random uplink channel is designed to allow for a more efficient use of the power amplifiers and includes features to assist the satellite receivers to resolve overlapping reception of multiple messages. This paper presents the performance results of an over‐the‐air test campaign carried out exploiting the NorSat‐2 Low Earth orbit (LEO) satellite. After a review of the VDE‐SAT RAC and Link ID 20 burst, a possible demodulator implementation is shown. Then, the VDE‐SAT transmitter platform, located in Pisa, Italy, emulating a population of vessels transmitting to the NorSat‐2 LEO satellite is introduced, and the test cases are described. Afterward, the analysis of the recorded signals is provided. The post‐analysis first focuses on the demodulation performance in terms of probability of successful demodulation of the interfering bursts. Further investigation has also been carried out to better understand the interference environment in this frequency band for satellite signal reception. Tests indicate promising results of successfully detecting and demodulating up to 22 overlapping RAC messages, confirming the robustness of the protocol. Finally, capitalizing on the above analysis, conclusions suggest possible improvements.

Maxwell field in spatially flat FLRW space-times

The classical and quantum theory of the Maxwell free field (or perturbation) minimally coupled to the gravity of local-Minkowskian spatially flat Friedmann–Lemaître–Robertson–Walker (FLRW) space-times is constructed in conformal local charts (herein called frames) where the Maxwell equations have the same form as in special relativity. Taking into account that the conformal coordinates cannot be measured directly, all the obtained results are transformed in physical frames, with cosmic time and space coordinates of Painlevé type, where these may take on a physical meaning. In these frames, the Maxwell theory is equivalent to the electrodynamics in flat macroscopic media whose constitutive equations predict magnetoelectric type effects interpreted here as a geometric induction. The given example is of a system of static charges giving rise simultaneously to time-dependent electric and magnetic fields that can be measured in physical frames. The quantization of the Maxwell free field in these manifolds is performed in a canonical manner using the momentum-helicity basis. The propagators in conformal and physical frames and the principal one-particle operators are written down. It is shown that this approach reveals a new behaviour of the one-particle wave packets during propagation and specific effects produced by the apparent horizons of the observers staying at rest in their proper physical frames.

Triple Hill’s Vortex Synthetic Eddy Method

The generation of initial or inflow synthetic turbulent velocity or scalar fields reproducing statistical characteristics of realistic turbulence is still a challenge. The synthetic eddy method, previously introduced in the context of inflow conditions for large eddy simulations, is based on the assumption that turbulence can be regarded as a superposition of coherent structures. In this paper, a new type of synthetic eddy method is proposed, where the fundamental eddy is constructed by superposing three Hill's vortices, with their axes orthogonal to each other. A distribution of Hill's vortices is used to synthesize an anisotropic turbulent velocity field that satisfies the incompressibility condition and match a given Reynolds stress tensor. The amplitudes of the three vortices that form the fundamental eddy are calculated from known Reynolds stress profiles through a transformation from the physical reference frame to the principal-axis reference frame. In this way, divergence-free anisotropic turbulent velocity fields are obtained that can reproduce a given Reynolds stress tensor. The model was tested on both isotropic and anisotropic turbulent velocity fields, in the framework of grid turbulence decay and turbulent channel flow, respectively. The transition from artificial to realistic turbulence in the proximity to the inflow boundary was found to be small in all test cases that were considered.

L’eSoi : de l’hypotrophie de la représentation du corps à l’hypertrophie de l’image du soi

Screens bring a new element to the environment of the child and even more to that of the adolescent. As a new partner in their development, screens are increasingly retaining the child's attention, and have multiple effects. They alter the relationship to space, time and attention and introduce a new dimension in the construction of the sexuality of young people. They are challenging–for the moment–educational practices. But the impact of screens on young people also depends a lot on the context of use and the environment in which they live. Alongside the child, there are parents, with their educational practices and their own use of screens, and there is society, with its values, the benchmarks it offers to its members, its culture and its models. Screens have become ubiquitous and invite humans to interact through their accessibility, the amusing simplicity of their job and their possibilities of interactivity. This tool will promote and even stimulate the child's empowerment vis-à-vis parents in his discovery and exploration of the world. Access to a screen connected to the Internet explodes the possibilities of interactions and exploration of a virtual space that is almost infinite. More and more, there is a striking contrast between the increasing spatial framing of the child confined in socially dedicated places, the room, the parental apartment, then the school, spaces set up for his protection… and his freedom to explore and interact with the virtual environment made possible by the connected screens that parents offer him. For safety reasons, children, especially younger ones, are no longer being opened to the streets, and they spend less and less time in parks or natural spaces (forests, fields, rivers, etc.). Children are increasingly reclusive in the interior spaces of homes and in playgrounds designed for their safety, which sanitizes the encounter with the natural environment. In contrast to this physical framing, the child's framing in the discovery and exploration of the virtual world increasingly escapes parents, despite the “parental control” devices. In this article, we try to identify some of the effects of the significant use of screens by children and adolescents on the construction of space and on the relationship to their bodies illustrating it in clinical vignettes. Indeed, the body-environment interaction is at the basis of the construction of the representation of one's own body, as well as that of space, essential for the building of identity.

الوعی الجسمانی: دراسة فی جمالیات الجسد

إن المتأمل لطبيعة الجسد يلحظ أنه لا يمکن عده جسدا مصمتا، أو أداة للإدراک فحسب؛ وإنما الجسد هو– أيضا- جهاز معرفي، وأداة للرؤية، والتعبير عن أفکارنا وتحويلها إلى أشياء مجسدة في الواقع. فالجسد البشري ليس مجرد إطار جسماني أو مظهر خارجي للإنسان؛ وإنما هو أسلوب حضورنا وتعبيرنا في العالم. أو بتعبير آخر، هو وعي جسماني ملتحم بالعالم. وأما في الفن، فالجسد بمنزلة تشکيل بصري أو علامة مرئية؛ مادام بإمکانه تجسيد المعنى من خلال لغة الإيماءة، التي تبطن– بدورها- المعاني والدلالات. تسعى الدراسة إلى تسليط الضوء على تجليات الجسد في الأعمال الفنية ليس بوصفه صورة فنية، يتواصل معها المتلقي فحسب؛ وإنما يمتد ليشمل–کذلک- کونه الوسيط المادي للعمل الفني، مع بيان الکيفية التي تخاطب بها الأعمال الفنية إدراکنا الحسي ومشاعرنا من خلال إيماءات تجسد أفکارا ومعاني. کما تناقش الدراسة دور الجسد في العملية الإبداعية، مع بيان طبيعة العمل الفني ليس بوصفه إعادة إنتاج لفکرة معطاة سلفا؛ وإنما المعنى يکون– بخلاف ذلک- متجسدا في تعبير الفنان الفيزيقي، أي في عمله الفني. وبذلک فإن هذه الدراسة تحاول الإجابة عن التساؤلات التالية: هل الجسد الحي مجرد موضوع فيزيقي حاضر أمام الوعي، أو هو نفسه وعي جسماني ملتحم بالعالم؟ وإن کان الجسد وعيا متجسدا، فهل الإبداع نشاط ذهني روحي يجري على مستوى الخيال، أو تلتحم فيه الرؤية الذهنية برؤية العين واليد؟ وبأي معنى تتأصل الخبرة الجمالية على مستوى خبرتي الإبداع والتلقي في الجسد؟ وهل الوشم– بدوره- انتهاک للجسد، أو هو أسلوب من أساليب التعبير الإبداعي؟ ومن أجل الإجابة عن تلک الأسئلة السابقة، فإن الدراسة سعت إلى استخدام المنهج التحليلي النقدي، الذي يهدف إلى تحليل المفاهيم والمشکلات المتضمنة في قضية البحث، وقراءة النصوص قراءة نقدية لا تکتفي بعرض الأفکار؛ وإنما تحاول فهمها وتحليلها، ومن ثم تقييمها. When contemplating the nature of the body, it is observed that it could not be considered as a solid body, or just a tool for realization. A body is a cognitive instrument, and a tool for vision and for expressing our ideas and converting them into embodied matters in reality. The human body is not a mere physical frame or an external appearance of the human being; it is the method of our presence and expression in the world. In other words, it is a body consciousness merged with the world. While in art, the body is considered to be a visual formation or a visible sign, as long as it is able to embody the meaning through the use of the gesture language, in which the meanings and connotations are embedded. The study seeks to highlight the manifestations of the body in the artistic works; this is not only as an artistic image with which the recipient can communicate, but it also extends to the idea that the body is considered to be the physical medium of the artistic work, in addition to revealing the manner through which the artistic works address our sensory perception and our feelings through the gestures that embody ideas and meanings. Moreover, the study discusses the role of the body in the creativity process, in addition to revealing the nature of the artistic work as being a reproduction of a pre-given idea. On the contrary, the meaning is embodied in the physical expression of the artist, namely in his artistic work. Therefore, this study tries to answer the following questions; Is the alive body a mere physical subject that is present in front of the consciousness, or is itself a body consciousness that is merged with the world? If the body is considered to be an incarnate consciousness, is creativity is considered to be a mental and spiritual activity on the level of imagination; or in it the mental vision merges with the eye and hand visions? Which meaning in which the aesthetic experience of the body is rooted, on the levels of the two experiences of creativity and reception? Is tattoo considered to be an abuse of the body, or it is a manner of creative expressions? For answering the previous questions, the study sought to use the analytical-critical method that aims at analyzing the concepts and problems included in the research issue, in addition to reading the texts in a critical way that is not satisfied by expressing the ideas, however, it tries to understand and analyze them, then evaluate them.

Instant preheating in a scale invariant two measures theory

The instant preheating mechanism in the framework of a scale invariant two measures theory is studied. We introduce this mechanism into a non oscillating inflationary model as another possible solution to the reheating of the universe in this theory. In this framework, we consider that the model includes two scalar matter fields, the first a dilaton field, that transforms under scale transformations and it will be considered also as the field that drives inflation and the second, a scalar field which will interact with the inflaton through an effective potential. By assuming this interaction term, we obtain a scenario of instant radiation or decay of particles according to the domain the effective mass of the field that interacts with the inflaton. Also, we consider a scale invariant Yukawa interaction and then after performing the transition to the physical Einstein frame we obtain an expression for the decay rate from our scalar field going into two fermions. Besides, from specific decay rates, different constraints and bounds for the coupling parameters associated with our model are found.

Lyra scalar-tensor theory: A scalar-tensor theory of gravity on Lyra manifold

We present a scalar-tensor theory of gravity on a torsion-free and metric compatible Lyra manifold. This is obtained by generalizing the concept of physical reference frame by considering a scale function defined over the manifold. The choice of a specific frame induces a local base, naturally non-holonomic, whose structure constants give rise to extra terms in the expression of the connection coefficients and in the expression for the covariant derivative. In the Lyra manifold, transformations between reference frames involving both coordinates and scale change the transformation law of tensor fields, when compared to those of the Riemann manifold. From a direct generalization of the Einstein-Hilbert minimal action coupled with a matter term, it was possible to build a Lyra invariant action, which gives rise to the associated Lyra Scalar-Tensor theory of gravity (LyST), with field equations for $g_{\mu\nu}$ and $\phi$. These equations have a well-defined Newtonian limit, from which it can be seen that both metric and scale play a role in the description gravitational interaction. We present a spherically symmetric solution for the LyST gravity field equations. It dependent on two parameters $m$ and $r_{L}$, whose physical meaning is carefully investigated. We highlight the properties of LyST spherically symmetric line element and compare it to Schwarzchild solution.

Physical activity, sport and transnational migrant spaces in Shanghai, China: (Re)crafting contours of a metropolitan cityscape

This study examines associations between sport/physical activity space, community formation and social life among Shanghai’s highly skilled migrant demographic. There is limited illustration of the roles sport and physical exercise provision and spaces play in this migrant cohort’s lives, community formation and participation in their host societies. Yet, such evidence is of value in determining social policy, urban development and community engagement initiatives. Using a mixed-methods approach involving public policy critique, cultural and spatial analysis and virtual community investigation, this article provides a conceptual exploration of ways sport and physical activity frame individual and collective migrant experiences, and how such experiences enmesh with wider geo-spatial, political and domestic context. Amid Shanghai’s presentation as a globally attractive space, we reveal some of the complexities of the cityscape as an emblematic location for highly mobile, highly skilled migrants. A confluence of ideals about urban citizenship, social participation and localised physical activity/sport-based (inter)action, we note, articulate Shanghai anew, and contribute to debates on highly skilled transnational mobility and community formation.

Pre-Injection Site Investigations in a Poro-Elastic Description of the Svelvik Ridge

We present the results of a rock physics driven workflow to analyze and steer a planned CO2 migration campaign, it combines a rock-physical seismic model, reservoir model and Bayesian scenario framework to assess monitoring configurations. The injection of CO2 into the subsurface requires a detailed understanding of the petrophysical properties and rock physical frame of the formation under stress. The underlying assumptions made for the unconsolidated high porosity formation have a significant impact on the expected seismic response. For a shallow aquifer pressure and saturation dependent elastic parameters are derived within a rock physical description. Distinguishing pressure and saturation related changes of the acoustic impedance is subject to the sensitivities of the properties used to derive the underlying seismic P- and S-velocities as well as densities. These uncertainties can induce a non-negligible variability in the footprint of a seismic image of the CO2 plume. The rock physics model is based on a solid frame consisting of quartz and clay and saturated with water and gas. The integrated workflow coupled with dynamic simulations provides a possibility to define and evaluate conformance measures during operation. Within this context the workflow is applied to the extended Svelvik CO2 field laboratory, which can be considered as a big sandbox model with capabilities for up-scaling to larger storage formations. An experimental design assessing the sensitivity of the information present for the site is translated into a scenario-based ensemble of dynamic models. Following, a practical quantitative workflow for a-priori assessment of monitoring strategies in probabilistic conformance verification is demonstrated. The results provide insight into the impact of different aspects of geophysical monitoring configurations (e.g., sparsity, noise levels, detection thresholds and timing) on the conformance verification accuracy.