Boundary Tension Research Articles

Perspectives from the frontline of two North American community paramedicine programs: an observational, ethnographic study.

Community paramedicine is one emerging model filling gaps in rural healthcare delivery. It can expand the reach of primary care and public health service provision in underserviced rural communities through proactive engagement of paramedics in preventative care and chronic disease management. This study addressed key research priorities identified at the National Agenda for Community Paramedicine Research conference in Atlanta, USA in 2012. The motivations, job satisfaction and challenges from the perspectives of community paramedics and their managers pioneering two independent programs in rural North America were identified. An observational ethnographic approach was used to acquire qualitative data from participants, through informal discussions, semi-structured interviews, focus groups and direct observation of practice. During field trips over two summers, researchers purposively recruited participants from Ontario, Canada and Colorado, USA. These sites were selected on the basis of uncomplicated facilitation of ethics and institutional approval, the diversity of the programs and willingness of service managers to welcome researchers. Thematic analysis techniques were adopted for transcribing, de-identifying and coding data that allowed identification of common themes. This study highlighted that the innovative nature of the community paramedic role can leave practitioners feeling misunderstood and unsupported by their peers. Three themes emerged: the motivators driving participation, the transitional challenges facing practitioners and the characteristics of paramedics engaged in these roles. A major motivator is the growing use of ambulances for non-emergency calls and the associated need to develop strategies to combat this phenomenon. This has prompted paramedic service managers to engage stakeholders to explore ways they could be more proactive in health promotion and hospital avoidance. Community paramedicine programs are fostering collaborative partnerships between disciplines, while the positive outcomes for patients and health cost savings are tangible motivators for paramedic services and funders. Paramedics were motivated by a genuine desire to make a difference and attracted to the innovative nature of a role delivering preventative care options for patients. Transitional challenges included lack of self-regulation, navigating untraditional roles and managing role boundary tensions between disciplines. Community paramedics in this study were largely self-selected, genuinely interested in the concept and proactively engaged in the grassroots development of these programs. These paramedics were comfortable integrating and operating within multidisciplinary teams. Improved education and communication from paramedic service management with staff and external stakeholders might improve transitional processes and better support a culture of inclusivity for community paramedicine programs. Experienced and highly motivated paramedics with excellent communication and interpersonal skills should be considered for community paramedic roles. Practitioners who are proactive about community paramedicine and self-nominate for positions transition more easily into the role: they tend to see the 'bigger picture', have broader insight into public health issues and the benefits of integrative health care. They are more likely to achieve higher job satisfaction, remain in the role longer, and contribute to better long-term program outcomes. Paramedic services and policymakers can use these findings to incentivize career pathways in community paramedicine and understand those changes that might better support this innovative model.

Hydrodynamic limit for an anharmonic chain under boundary tension**This work has been partially supported by the grants ANR-15-CE40-0020-01 LSD of the French National Research Agency.

We study the hydrodynamic limit for the isothermal dynamics of an anharmonic chain under hyperbolic space-time scaling under varying tension. The temperature is kept constant by a contact with a heat bath, realised via a stochastic momentum-preserving noise added to the dynamics. The noise is designed to be large at the microscopic level, but vanishing in the macroscopic scale. Boundary conditions are also considered: one end of the chain is kept fixed, while a time-varying tension is applied to the other end. We show that the volume stretch and momentum converge (in an appropriate sense) to a weak solution of a system of hyperbolic conservation laws (isothermal Euler equations in Lagrangian coordinates) with boundary conditions. This result includes the shock regime of the system. This is proven by adapting the theory of compensated compactness to a stochastic setting, as developed by Fritz (2011 Arch. Ration. Mech. Anal. 201 209–49) for the same model without boundary conditions. Finally, changing the external tension allows us to define thermodynamic isothermal transformations between equilibrium states. We use this to deduce the first and the second principle of thermodynamics for our model.

An atomistic perspective on lithiation-induced stress in silicon nanopillars

We present reactive force field simulations that provide an atomistic understanding of lithiation-induced stress generation in silicon nanopillars. We investigate two-phase lithiation by developing a new protocol for simulation of formation and movement of an atomically sharp phase boundary. This protocol involves the layer-by-layer insertion of lithium atoms in the silicon lattice. The simulation results show the development of compressive stresses at the phase boundary and hoop tension near the surface of a Si nanopillar, thereby highlighting the atomistic underpinning of lithiation-induced stress. The work enables a direct mapping between atomistic and continuum modeling of lithiation-induced stress in large-volume-change electrodes.

Analysis on traditional fishing grounds in Indonesia`s Natuna waters under International Law

This paper examines the boundary tension between Indonesia and China regarding traditional fishing ground in Natuna. Indonesia`s Natuna island is claimed by the China government as its traditional fishing zone/ground. The inclusion of Natuna territory into China`s traditional fishing zone brings new problems to Indonesia, especially with the Chinese ships docked and entered Indonesia`s exclusive economic zone, as well as several cases of illegal fishing over the territorial waters of Indonesia. Claims on traditional fishing zones have the potential to threaten the sovereignty of the Indonesian territory. This study aims to analyze the claims of the traditional fishing rights of China over the waters of the Natuna Islands under international law, especially UNCLOS 1982. This study revealed that the china`s argument of traditional fishing ground in Natuna to the nine dash line map is a unilateral claim, there is no international legal norm that can be used as the legal basis. Indonesia and some ASEAN countries have Internationally validated bilateral agreement on the continental shelf (i.e. Indonesia-Vietnam and Indonesia-Malaysia) thus the inclusion of Natuna into China`s nine dash line map rejects the legal status of Indonesian water under UNCLOS 1982.

Study of Water-Oil Emulsion Breaking by Stabilized Solution Consisting of Anionic Surface Acting Agent – Soda Ash – Polymer (ASP)

The paper provides a laboratory research of breaking natural water-oil emulsions: - by non-stabilized ASP; by stabilized ASP; by mixture of stabilized and non-stabilized ASP in different proportions and production of refinery water of the required quality with the use of IronGuard 2495 as flocculant. Oil-in-water emulsion is stable. Classic methods are not suitable for residual water treatment: sediment gravity flow; filtration; centrifuge test. Microemulsion formed after ASP application has low boundary tension and high pH. It contributes to transfer of oil phase into a water one, forming oil-in-water emulsion. Alkaline condition has adverse effect on demulsifying ability of agents, flocculation and boundary tension. For breaking of water-oil emulsion at EBU before the interchanger water or water-oil emulsion from the wells that were not APS-treated in ratio of 1:9 shall be delivered. Residual water after EBU must be prepared in water tanks by dilution in great volume.

Partial wetting of thin solid sheets under tension.

We consider the equilibrium of liquid droplets sitting on thin elastic sheets that are subject to a boundary tension and/or are clamped at their edge. We use scaling arguments, together with a detailed analysis based on the Föppl-von-Kármán equations, to show that the presence of the droplet may significantly alter the stress locally if the tension in the dry sheet is weak compared to an intrinsic elasto-capillary tension scale γ2/3(Et)1/3 (with γ the droplet surface tension, t the sheet thickness and E its Young modulus). Our detailed analysis suggests that some recent experiments may lie in just such a "non-perturbative" regime. As a result, measurements of the tension in the sheet at the contact line (inferred from the contact angles of the sheet with the liquid-vapour interface) do not necessarily reflect the true tension within the sheet prior to wetting. We discuss various characteristics of this non-perturbative regime.

Navigating professional and prescribing boundaries: Implementing nurse prescribing in New Zealand.

Non-medical prescribing is now well established in a number of countries. Because prescribing has traditionally been viewed as a medical role, there are inevitable interprofessional boundary tensions when non-medical prescribing is introduced. In New Zealand, enabling legislation has allowed nurse practitioners to apply for prescriptive authority after undertaking appropriate educational preparation. This study explored the experiences and perspectives of one of the first cohorts of nurse prescribers and their strategies in establishing the role and negotiating the associated professional boundaries. Semi-structured interviews were undertaken with ten newly registered nurse-prescribers. Two broad categories, each comprising three themes, were identified: 'shifting professional boundaries' and 'navigating boundaries of practice'. Participants described how they were faced with the challenge of an unprepared environment as they began to prescribe and how they built trust in their prescribing practice among their colleagues and patients. They also related how they determined their personal prescribing boundaries in this new environment. They described the new professional relationship between nurse prescribers and doctors as collaborative, but with the crucial difference of it being interdependent, not dependent. The study offers insights into the challenges associated with the establishment of new professional roles such as prescribing.

Vibration control and boundary tension constraint of an axially moving string system

This paper is concerned with vibration control and boundary tension constraint of an axially moving string system. The main control objectives are to suppress the vibration of the string system and ensure the boundary tension in a constrained region. To this end, a boundary control strategy is developed via constructing a proper barrier Lyapunov function. In addition, the disturbance observer including the barrier term is introduced to tackle the effects of unknown boundary disturbance. With the proposed control strategy, the states of the closed-loop system are proven to be uniformly ultimately bounded through rigorous Lyapunov analysis and the boundary tension constraint is not violated. Finally, in order to validate the effectiveness of the proposed control, the simulation results are presented by choosing appropriate control design parameters.

Civil Repair and Boundary Tension Between Civil Sphere and Economic Sphere: The Cases of Credit Amnesty and Credit Information Breach

Civil Repair and Boundary Tension Between Civil Sphere and Economic Sphere: The Cases of Credit Amnesty and Credit Information Breach

Using Auger electron spectroscopy to assess the effect of segregation on the interfacial characteristics of polycrystalline copper

The possibility of using AES data on the composition of a free surface to assess surface and grain boundary tensions, and the grain boundary strength of polycrystalline copper, is discussed. Using familiar theoretical models, it is shown that sulfur impurity segregation substantially reduces these characteristics, with the energy of grain boundary fracture lowered by 5–8%.

Role of Boundary Organization after a Disaster: New Zealand’s Natural Hazards Research Platform and the 2010–2011 Canterbury Earthquake Sequence

AbstractThe boundary organization concept has been used to establish that collaborative arrangements and outputs across science and policy domain boundaries need to be credible, relevant, and legitimate in order to be to be effective. Although widely accepted in other issue-driven fields, this concept does not have equivalent currency in the natural hazard and disaster risk reduction context. This paper uses the development of the New Zealand Natural Hazards Research Platform during a recent earthquake disaster to assess the utility of the concept in this topic area. Lessons are also identified concerning the use of larger consortium organizations to increase policy and other end-user involvement in the management and coordination of research funding, and the impact of a major disaster on this research-funding initiative. Mapping the Platform’s collaborative arrangements in relation to boundary tensions over time makes it possible to distinguish disaster effects from preexisting and ongoing structural eff...

The work of local healthcare innovation: a qualitative study of GP-led integrated diabetes care in primary health care.

BackgroundService delivery innovation is at the heart of efforts to combat the growing burden of chronic disease and escalating healthcare expenditure. Small-scale, locally-led service delivery innovation is a valuable source of learning about the complexities of change and the actions of local change agents. This exploratory qualitative study captures the perspectives of clinicians and managers involved in a general practitioner-led integrated diabetes care innovation.MethodsData on these change agents’ perspectives on the local innovation and how it works in the local context were collected through focus groups and semi-structured interviews at two primary health care sites. Transcribed data were analysed thematically. Normalization Process Theory provided a framework to explore perspectives on the individual and collective work involved in putting the innovation into practice in local service delivery contexts.ResultsTwelve primary health care clinicians, hospital-based medical specialists and practice managers participated in the study, which represented the majority involved in the innovation at the two sites. The thematic analysis highlighted three main themes of local innovation work: 1) trusting and embedding new professional relationships; 2) synchronizing services and resources; and 3) reconciling realities of innovation work. As a whole, the findings show that while locally-led service delivery innovation is designed to respond to local problems, convincing others to trust change and managing the boundary tensions is core to local work, particularly when it challenges taken-for-granted practices and relationships. Despite this, the findings also show that local innovators can and do act in both discretionary and creative ways to progress the innovation.ConclusionsThe use of Normalization Process Theory uncovered some critical professional, organizational and structural factors early in the progression of the innovation. The key to local service delivery innovation lies in building coalitions of trust at the point of service delivery and persuading organizational and institutional mindsets to consider the opportunities of locally-led innovation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12913-016-1270-4) contains supplementary material, which is available to authorized users.

Working in Complexity: Ethics and Boundaries in Community Work and Mental Health

ABSTRACTWhile codes of ethical conduct are important, they do not always fit neatly in the organic community settings in which some workers engage. Professional standards from accrediting bodies are easy to sign up to, yet much more difficult to put into practice. Drawing upon community connection practice in recovery-oriented mental health work, this article names the professional boundary tensions peculiar to less structured fields of engagement. We suggest that for workers in these fields, there has been a disconnection between the theory, the experience, and the public discourse of professional boundaries. We argue that such disconnection can create uncertainty, anxiety, and secrecy, creating exactly those cultures we wish to avoid. Ultimately this leads to greater harm for vulnerable individuals, as well as the workers and organisations that serve them. The alternative is to engage in what we name a “risky conversation,” to expose this disconnect and engender a new type of professionalism.

Step free energy of an arbitrarily oriented step on a rectangular lattice with nearest-neighbor interactions

We have derived within the framework of a solid-on-solid model with anisotropic nearest-neighbor interactions an exact expression for the free energy of an arbitrarily oriented step edge or boundary on a rectangular two-dimensional lattice. The full angular dependence of the step free energy allows the determination of the surface free energy of any vicinal surface as well as the temperature evolution of the equilibrium island shape. Our method can also be applied to derive an expression for the boundary tension of an arbitrarily oriented domain boundary of the anisotropic nearest neighbor two-dimensional Ising model

Geometry Regulates Traction Stresses in Adherent Cells

Cells generate mechanical stresses via the action of myosin motors on the actin cytoskeleton. Although the molecular origin of force generation is well understood, we currently lack an understanding of the regulation of force transmission at cellular length scales. Here, using 3T3 fibroblasts, we experimentally decouple the effects of substrate stiffness, focal adhesion density, and cell morphology to show that the total amount of work a cell does against the substrate to which it is adhered is regulated by the cell spread area alone. Surprisingly, the number of focal adhesions and the substrate stiffness have little effect on regulating the work done on the substrate by the cell. For a given spread area, the local curvature along the cell edge regulates the distribution and magnitude of traction stresses to maintain a constant strain energy. A physical model of the adherent cell as a contractile gel under a uniform boundary tension and mechanically coupled to an elastic substrate quantitatively captures the spatial distribution and magnitude of traction stresses. With a single choice of parameters, this model accurately predicts the cell’s mechanical output over a wide range of cell geometries.

Theoretical study of line and boundary tension in adsorbed colloid-polymer mixtures.

An extended theoretical study of interface potentials in adsorbed colloid-polymer mixtures is performed. To describe the colloid-polymer mixture near a hard wall, a simple Cahn-Nakanishi-Fisher free-energy functional is used. The bulk phase behaviour and the substrate-adsorbate interaction are modelled by the free-volume theory for ideal polymers with polymer-to-colloid size ratios q = 0.6 and q = 1. The interface potentials are constructed with help from a Fisher-Jin crossing constraint. By manipulating the crossing density, a complete interface potential can be obtained from natural, single-crossing, profiles. The line tension in the partial wetting regime and the boundary tension along prewetting are computed from the interface potentials. The line tensions are of either sign, and descending with increasing contact angle. The line tension takes a positive value of 10(-14)-10(-12) N near a first-order wetting transition, passes through zero and decreases to minus 10(-14)-10(-12) N away from the first-order transition. The calculations of the boundary tension along prewetting yield values increasing from zero at the prewetting critical point up to the value of the line tension at first-order wetting.

Estuary planning and management: the case of Vouga Estuary (Ria de Aveiro), Portugal

Estuarine areas often concentrate complex and conflicting sets of natural, economic and social resources and activities with multiple challenges to planning and management approaches as well as to governance practices. Using a set of integration factors depicted from the literature review, the paper analyzes the main features of the new set of the Portuguese estuary types of plans and assesses their potential added value, while focusing the analysis on the estuary of the Vouga River (Ria de Aveiro). The results are twofold. On the one side, their uniqueness, by treating the estuary as a planning unit, integrating the water resources and the land use planning systems and by establishing mandatory rules for the estuary uses, embodies relevant potential for reducing boundary tensions and to improve integrative approaches. On the other side, while at the level of plan content the contribution of the Portuguese Estuary Land Use and Management Plans (Planos de Ordenamento de Estuário) legislation brings strong new prospects for integration, at the level of planning process and implementation, further efforts should be undertaken. Their added value, especially in complex institutional and societal estuarine contexts, such as the Ria de Aveiro, strongly depends on more robust participation schemes through which knowledge, institutions, aims and measures are articulated in a collective vision and shared governance process.

Cellular geometry regulates traction stresses (LB228)

Cells generate mechanical stresses via the action of myosin motors on the actin cytoskeleton. While the molecular origin of force generation is well understood, we currently lack an understanding of the regulation of force transmission at cellular length scales. Here we experimentally decouple the effects of substrate stiffness, focal adhesion density and cell morphology to show that the total amount of work a cell does against the substrate to which it is adhered is regulated by the cell spread area alone. Surprisingly, the number of focal adhesions and the substrate stiffness have little effect on regulating the work done on the substrate by the cell. For a given spread area, the local curvature along the cell edge regulates the distribution and magnitude of traction stresses to maintain a constant strain energy. A physical model of the adherent cell as a contractile gel under a uniform boundary tension and mechanically coupled to an elastic substrate quantitatively captures the spatial distribution and magnitude of traction stresses. With a single choice of parameters, this model accurately predicts the cell's mechanical output as a function of cell geometry.Grant Funding Source: Supported by the NSF, NIH and the Burroughs Wellcome Fund.

Cellular geometry regulates traction stresses (479.4)

Cells generate mechanical stresses via the action of myosin motors on the actin cytoskeleton. While the molecular origin of force generation is well understood, we currently lack an understanding of the regulation of force transmission at cellular length scales. Here we experimentally decouple the effects of substrate stiffness, focal adhesion density and cell morphology to show that the total amount of work a cell does against the substrate to which it is adhered is regulated by the cell spread area alone. Surprisingly, the number of focal adhesions and the substrate stiffness have little effect on regulating the work done on the substrate by the cell. For a given spread area, the local curvature along the cell edge regulates the distribution and magnitude of traction stresses to maintain a constant strain energy. A physical model of the adherent cell as a contractile gel under a uniform boundary tension and mechanically coupled to an elastic substrate quantitatively captures the spatial distribution and magnitude of traction stresses. With a single choice of parameters, this model accurately predicts the cell's mechanical output as a function of cell geometry.Grant Funding Source: Supported by the NSF, NIH and the Burroughs Wellcome Fund.

Boundary Tension at the Interface of Nanoscopic Helium Films on an Heterogeneous Substrate

This paper reports the first calculation of the two-dimensional interfacial profile and energetics of nanoscopically thin films of helium, on an heterogeneous planar substrate consisting of two adjoining metals. The calculations are performed in the frame of density functional theory at zero temperature, with the purpose of identifying the formation process of the interface at the boundary between the two substrates when few atomic layers are involved, to elucidate the possible relationship of the magnitude of the boundary tension with the displacement of layers between the half films, and to extract keys to organize future calculations of film coexistence at finite temperatures.