Mathematical models in physiology

Computational modelling of biological processes and systems has witnessed a remarkable development in recent years. The search-term (modelling OR modeling) yields over 58000 entries in PubMed, with more than 34000 since the year 2000: thus, almost two-thirds of papers appeared in the last 5–6 years, compared to only about one-third in the preceding 5–6 decades.\ud \ud The development is fuelled both by the continuously improving tools and techniques available for bio-mathematical modelling and by the increasing demand in quantitative assessment of element inter-relations in complex biological systems. This has given rise to a worldwide public domain effort to build a computational framework that provides a comprehensive theoretical representation of integrated biological function—the Physiome.\ud \ud The current and next issues of this journal are devoted to a small sub-set of this initiative and address biocomputation and modelling in physiology, illustrating the breadth and depth of experimental data-based model development in biological research from sub-cellular events to whole organ simulations

Emergency Medicine Palliative Care Access (EMPallA): Protocol for a multicentre randomised controlled trial comparing the effectiveness of specialty outpatient versus nurse-led telephonic palliative care of older adults with advanced illness

Introduction Emergency department (ED)-initiated palliative care has been shown to improve patient-centred outcomes in older adults with serious, life-limiting illnesses. However, the optimal modality for providing such interventions is unknown. This study aims to compare nurse-led telephonic case management to specialty outpatient palliative care for older adults with serious, life-limiting illness on: (1) quality of life in patients; (2) healthcare utilisation; (3) loneliness and symptom burden and (4) caregiver strain, caregiver quality of life and bereavement. Methods and analysis This is a protocol for a pragmatic, multicentre, parallel, two-arm randomised controlled trial in ED patients comparing two established models of palliative care: nurse-led telephonic case management and specialty, outpatient palliative care. We will enrol 1350 patients aged 50+ years and 675 of their caregivers across nine EDs. Eligible patients: (1) have advanced cancer (metastatic solid tumour) or end-stage organ failure (New York Heart Association class III or IV heart failure, end-stage renal disease with glomerular filtration rate /min/m2, or global initiative for chronic obstructive lung disease stage III, IV or oxygen-dependent chronic obstructive pulmonary disease); (2) speak English; (3) are scheduled for ED discharge or observation status; (4) reside locally; (5) have a working telephone and (6) are insured. Patients will be excluded if they: (1) have dementia; (2) have received hospice care or two or more palliative care visits in the last 6 months or (3) reside in a long-term care facility. We will use patient-level block randomisation, stratified by ED site and disease. Effectiveness will be compared by measuring the impact of each intervention on the specified outcomes. The primary outcome will measure change in patient quality of life. Ethics and dissemination Institutional Review Board approval was obtained at all study sites. Trial results will be submitted for publication in a peer-reviewed journal

Chaotic exploration and learning of locomotion behaviours

We present a general and fully dynamic neural system, which exploits intrinsic chaotic dynamics, for the real-time goal-directed exploration and learning of the possible locomotion patterns of an articulated robot of an arbitrary morphology in an unknown environment. The controller is modeled as a network of neural oscillators that are initially coupled only through physical embodiment, and goal-directed exploration of coordinated motor patterns is achieved by chaotic search using adaptive bifurcation. The phase space of the indirectly coupled neural-body-environment system contains multiple transient or permanent self-organized dynamics, each of which is a candidate for a locomotion behavior. The adaptive bifurcation enables the system orbit to wander through various phase-coordinated states, using its intrinsic chaotic dynamics as a driving force, and stabilizes on to one of the states matching the given goal criteria. In order to improve the sustainability of useful transient patterns, sensory homeostasis has been introduced, which results in an increased diversity of motor outputs, thus achieving multiscale exploration. A rhythmic pattern discovered by this process is memorized and sustained by changing the wiring between initially disconnected oscillators using an adaptive synchronization method. Our results show that the novel neurorobotic system is able to create and learn multiple locomotion behaviors for a wide range of body configurations and physical environments and can readapt in realtime after sustaining damage

Temperature-dependent Fermi surface evolution in heavy fermion CeIrIn5

In Cerium-based heavy electron materials, the 4f electron's magnetic moments bind to the itinerant quasiparticles to form composite heavy quasiparticles at low temperature. The volume of the Fermi surfacein the Brillouin zone incorporates the moments to produce a "large FS" due to the Luttinger theorem. When the 4f electrons are localized free moments, a "small FS" is induced since it contains only broad bands of conduction spd electrons. We have addressed theoretically the evolution of the heavy fermion FS as a function of temperature, using a first principles dynamical mean-field theory (DMFT) approach combined with density functional theory (DFT+DMFT). We focus on the archetypical heavy electrons in CeIrIn5, which is believed to be near a quantum critical point. Upon cooling, both the quantum oscillation frequencies and cyclotron masses show logarithmic scaling behavior (~ ln(T_0/T)) with different characteristic temperatures T_0 = 130 and 50 K, respectively. The resistivity coherence peak observed at T ~ 50 K is the result of the competition between the binding of incoherent 4f electrons to the spd conduction electrons at Fermi level and the formation of coherent 4f electrons.Comment: 5 pages main article,3 figures for the main article, 2 page Supplementary information, 2 figures for the Supplementary information. Supplementary movie 1 and 2 are provided on the webpage(http://www-ph.postech.ac.kr/~win/supple.html

BIM-based mixed-reality application for bridge inspection and maintenance

Purpose – The purpose of this study is to develop a BIM-based mixed reality (MR) application to enhance and facilitate the process of managing bridge inspection and maintenance works remotely from office. It aims to address the ineffective decision-making process on maintenance tasks from the conventional method which relies on documents and 2D drawings on visual inspection. This study targets two key issues: creating a BIM-based model for bridge inspection and maintenance; and developing this model in a MR platform based on Microsoft Hololens. Design/methodology/approach – Literature review is conducted to determine the limitation of MR technology in the construction industry and identify the gaps of integration of BIM and MR for bridge inspection works. A new framework for a greater adoption of integrated BIM and Hololens is proposed. It consists of a bridge information model for inspection and a newly-developed Hololens application named “HoloBridge”. This application contains the functional modules that allow users to check and update the progress of inspection and maintenance. The application has been implemented for an existing bridge in South Korea as the case study. Findings – The results from pilot implementation show that the inspection information management can be enhanced because the inspection database can be systematically captured, stored and managed through BIM-based models. The inspection information in MR environment has been improved in interpretation, visualization and visual interpretation of 3D models because of intuitively interactive in real-time simulation. Originality/value – The proposed framework through “HoloBridge” application explores the potential of integrating BIM and MR technology by using Hololens. It provides new possibilities for remote inspection of bridge conditions

Analytic study of the three-urn model for separation of sand

We present an analytic study of the three-urn model for separation of sand. We solve analytically the master equation and the first-passage problem. We find that the stationary probability distribution obeys the detailed balance and is governed by the {\it free energy}. We find that the characteristic lifetime of a cluster diverges algebraically with exponent 1/3 at the limit of stability.Comment: 5pages, 4 figures include

Massive Lyman Break Galaxies at z~3 in the Spitzer Extragalactic First Look Survey

We investigate the properties of 1088 Lyman Break Galaxies (LBGs) at z~3 selected from a ~2.63$deg2 sub-region of the First Look Survey field using the ground-based multi-color data and the Spitzer Space Telescope mid-infrared data at 3--8 and 24 um. With the wide area and the broad wavelength coverage, we sample a large number of ``rare'' u-band dropouts which are massive (M* > 10^11 Msun), allowing us to perform a statistical analysis of these subsets of LBGs that have not been studied in detail. Optically bright (R(AB) < 24.5 mag) LBGs detected in mid-infrared (S_{3.6um} > 6 uJy) reside at the most massive and dusty end of the LBG population, with relatively high and tight$M/L$ in rest-frame near-infrared. Most infrared-luminous LBGs (S_{24um} > 100 uJy) are dusty star-forming galaxies with star formation rates of 100--1000 Msun/yr, total infrared luminosity of > 10^12 Lsun. By constructing the UV luminosity function of massive LBGs, we estimate that the lower limit for the star formation rate density from LBGs more massive than 10^11 Msun at z~3 is > 3.3 x 10^-3 Msun/yr/Mpc^3, showing for the first time that the UV-bright population of massive galaxies alone contributes significantly to the global star formation rate density at z~3. When combined with the star formation rate densities at z < 2, our result reveals a steady increase in the contribution of massive galaxies to the global star formation from z=0 to z=3, providing strong support to the downsizing of galaxy formation.Comment: 15 pages, 13 figures. Accepted for publication in Ap