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Tipping point

Andreas Widder, Christian Kuehn
In this paper, we focus on the influence of heterogeneity and stochasticity of the population on the dynamical structure of a basic susceptible-infected-susceptible (SIS) model. First we prove that, upon a suitable mathematical reformulation of the basic reproduction number, the homogeneous system and the heterogeneous system exhibit a completely analogous global behaviour. Then we consider noise terms to incorporate the fluctuation effects and the random import of the disease into the population and analyse the influence of heterogeneity on warning signs for critical transitions (or tipping points)...
October 1, 2016: Mathematical Biosciences and Engineering: MBE
Seung Jae Paek, Ji Yong Yoo, Jang Won Lee, Won-Jong Park, Young Deok Chee, Moon Gi Choi, Eun Joo Choi, Kyung-Hwan Kwon
BACKGROUND: The aims of this study are to evaluate the lip morphology and change of lip commissure after mandibular setback surgery (MSS) for class III patients and analyze association between the amount of mandibular setback and change of lip morphology. METHODS: The samples consisted of 14 class III patients treated with MSS using bilateral sagittal split ramus osteotomy. Lateral cephalogram and cone-beam CT were taken before and about 6 months after MSS. Changes in landmarks and variables were measured with 3D software program Ondemand™...
December 2016: Maxillofacial Plastic and Reconstructive Surgery
I Tzanakis, G S B Lebon, D G Eskin, K A Pericleous
A bespoke cavitometer that measures acoustic spectrum and is capable of operating in a range of temperatures (up to 750°C) was used to study the cavitation behaviour in three transparent liquids and in molten aluminium. To relate these acoustic measurements to cavitation development, the dynamics of the cavitation bubble structures was observed in three Newtonian, optically transparent liquids with significantly different physical properties: water, ethanol, and glycerine. Each liquid was treated at 20kHz with a piezoelectric ultrasonic transducer coupled to a titanium sonotrode with a tip diameter of 40mm...
January 2017: Ultrasonics Sonochemistry
Masoud Rahimi, Salman Movahedirad, Shahrokh Shahhosseini
Recently, great attention has been paid to predict the acoustic streaming field distribution inside the sonoreactors, induced by high-power ultrasonic wave generator. The focus of this paper is to model an ultrasonic vibrating horn and study the induced flow pattern with a newly developed moving boundary condition. The numerical simulation utilizes the modified cavitation model along with the "mixture" model for turbulent flow (RNG, k-ε), and a moving boundary condition with an oscillating parabolic-logarithmic profile, applied to the horn tip...
October 17, 2016: Ultrasonics Sonochemistry
Yun Kyoung Ryu, Reilley P Mathena, Sanghee Lim, Minhye Kwak, Michael Xu, Cyrus D Mintz
BACKGROUND: Early postnatal exposure to general anesthetic agents causes a lasting impairment in learning and memory in animal models. One hypothesis to explain this finding is that exposure to anesthetic agents during critical points in neural development disrupts the formation of brain circuitry. Here, we explore the effects of sevoflurane on the neuronal growth cone, a specialization at the growing end of axons and dendrites that is responsible for the targeted growth that underlies connectivity between neurons...
October 2016: Journal of Neurosurgical Anesthesiology
Michael Talerico, Jaimo Ahn
The objective of this article is to highlight the salient points of preoperative planning, intraoperative considerations for fracture reduction methods, and implant fixation when treating distal diaphyseal or diametaphyseal tibia fractures with an intramedullary nail. Through review of the necessary preoperative considerations, techniques available to hold and maintain a reduction, and lastly how to maximize the selected implant of intramedullary nail, we hope to assist the treating surgeon in simplifying these sometimes complex fractures into manageable injuries that can be treated successfully with an intramedullary implant...
November 2016: Journal of Orthopaedic Trauma
E A Gopalakrishnan, Yogita Sharma, Tony John, Partha Sharathi Dutta, R I Sujith
Dynamical systems can undergo critical transitions where the system suddenly shifts from one stable state to another at a critical threshold called the tipping point. The decrease in recovery rate to equilibrium (critical slowing down) as the system approaches the tipping point can be used to identify the proximity to a critical transition. Several measures have been adopted to provide early indications of critical transitions that happen in a variety of complex systems. In this study, we use early warning indicators to predict subcritical Hopf bifurcation occurring in a thermoacoustic system by analyzing the observables from experiments and from a theoretical model...
October 21, 2016: Scientific Reports
Peter M Chapman
We are facing a dynamic future in the face of multiple stressors acting individually and in combination: climate change; habitat change/loss; overfishing; invasive species; harmful algal blooms/eutrophication; and, chemical contaminants. Historic assessment and management approaches will be inadequate for addressing risks from climate change and other stressors. Wicked problems (non-linear, complex, competing risks and benefits, not easily solvable), will become increasingly common. We are facing irreversible changes to our planetary living conditions...
October 16, 2016: Marine Pollution Bulletin
Mathieu Jacquemart, Pierre Bouletreau, Pierre Breton, Ali Mojallal, Nicolas Sigaux
Video must now be considered as a precious tool for learning surgery. However, the medium does present production challenges, and currently, quality movies are not always accessible. We developed a series of 7 surgical videos and made them available on a publicly accessible internet website. Our videos have been viewed by thousands of people worldwide. High-quality educational movies must respect strategic and technical points to be reliable.
September 2016: Plastic and Reconstructive Surgery. Global Open
Thomas Weber
Validation of a medical device measuring a biomarker is a complex process, involving technical aspects (What is actually measured by the device, and how is this done ? Is the measurement reproducible ? Is there a gold standard for measurement of the particular biomarker ? If yes, how accurate and how precise are the measurements by the device, compared to the gold standard ?) and clinical aspects (Do the measurements predict outcome ? If yes, is there added value, when standard clinical parameters are considered ? Is there a treatment strategy, based on the mesurements of the novel device ? Is this strategy cost-effective ?)...
September 2016: Journal of Hypertension
Herbert H Dedo
The tools described in this article are verified to be Greco-Roman medical and surgical instruments for the eye, ear, nose, and throat. They include three myrtle leaf-shaped scalpels, three ear spoons, a "Q-tip," a forceps, a needle, and two arrow-pointed scalpels. One of the arrow-pointed scalpels is nearly identical to a Juerger keratome, suggesting that in Roman times, cataracts were extracted, not just "couched" into the posterior chamber. The description presented here goes beyond traditional archeological claims, because as a head and neck surgeon, I evaluated these instruments from a surgeon's point of view...
October 18, 2016: Laryngoscope
Jimmie Leppink, Patricia O'Sullivan, Kal Winston
The overall purpose of the 'Statistical Points and Pitfalls' series is to help readers and researchers alike increase awareness of how to use statistics and why/how we fall into inappropriate choices or interpretations. We hope to help readers understand common misconceptions and give clear guidance on how to avoid common pitfalls by offering simple tips to improve your reporting of quantitative research findings. Each entry discusses a commonly encountered inappropriate practice and alternatives from a pragmatic perspective with minimal mathematics involved...
October 17, 2016: Perspectives on Medical Education
Petras Prakas, Eglė Rudaitytė, Dalius Butkauskas, Liuda Kutkienė
In the present study, we describe Sarcocystis entzerothi n. sp. from the European roe deer (Capreolus capreolus) based on the microscopical and DNA analysis. By light microscopy (LM), cysts of S. entzerothi were spindle-shaped with pointed tips, 950-1900 × 70-150 μm in size and had 5-6 μm long finger-like cyst wall protrusions. Cyst wall of S. entzerothi by transmission electron microscopy (TEM) was type 10a-like; villar protrusions were up to 1.2 μm wide, densely packed, lying about 0.1 μm between each other, had profuse microgranules and microfilaments, parasitophorous vacuolar membrane had many minute invaginations, and the ground substance layer measured up to 0...
October 18, 2016: Parasitology Research
Chayanit Hempolchom, Thippawan Yasanga, Adulsak Wijit, Kritsana Taai, Watcharatip Dedkhad, Wichai Srisuka, Sorawat Thongsahuan, Yasushi Otsuka, Hiroyuki Takaoka, Atiporn Saeung
Antennal sensilla were first investigated in the eight medically and veterinary important Anopheles mosquito species (Anopheles argyropus, Anopheles crawfordi, Anopheles nigerrimus, Anopheles nitidus, Anopheles paraliae (= Anopheles lesteri), Anopheles peditaeniatus, Anopheles pursati, and Anopheles sinensis) of the Hyrcanus Group in Thailand, using scanning electron microscopy (SEM). Four types of sensilla, including sensilla chaetica (large and small), sensilla trichodea (sharp- and blunt-tipped), sensilla basiconica or grooved pegs (types I, II, and III), and sensilla coeloconica (large and small), were observed on the female antennae of the eight species...
October 18, 2016: Parasitology Research
Jorge Aramburu, Raúl Antón, Alejandro Rivas, Juan Carlos Ramos, Bruno Sangro, José Ignacio Bilbao
Radioembolization, which consist of the implantation of radioactive microspheres via intra-arterially placed microcatheter, is a safe and effective treatment for liver cancer. Nevertheless, radioembolization-related complications and side effects may arise, which are an active area of ongoing research. The catheter design has been claimed as an option in reducing these complications. In this paper, the influence of catheter type and location are investigated. The study was undertaken by numerically simulating the particle-hemodynamics in a patient-specific hepatic artery during liver radioembolization...
October 7, 2016: Journal of Biomechanics
Jorge Aramburu, Raúl Antón, Alejandro Rivas, Juan Carlos Ramos, Bruno Sangro, José Ignacio Bilbao
Liver radioembolization is a treatment option for patients with primary and secondary liver cancer. The procedure consists of injecting radiation-emitting microspheres via an intra-arterially placed microcatheter, enabling the deposition of the microspheres in the tumoral bed. The microcatheter location and the particle injection rate are determined during a pretreatment work-up. The purpose of this study was to numerically study the effects of the injection characteristics during the first stage of microsphere travel through the bloodstream in a patient-specific hepatic artery (i...
October 5, 2016: Journal of Biomechanics
Giles E Eperon, David Moerman, David S Ginger
We use high-resolution, spatially resolved, laser beam induced current, confocal photoluminescence, and photoconductive atomic force microscopy (pcAFM) measurements to correlate local solar cell performance with spatially heterogeneous local material properties in methylammonium lead triiodide (CH3NH3PbI3) perovskite solar cells. We find that, for this material and device architecture, the photocurrent heterogeneity measured via pcAFM on devices missing a top selective contact with traditional Au-coated tips is significantly larger than the photocurrent heterogeneity observed in full devices with both electron- and hole-selective extraction layers, indicating that extraction barriers at the Au/perovskite interface are ameliorated by deposition of the organic charge extraction layer...
October 17, 2016: ACS Nano
Athanasios Raikos, Thomas English, Omar Khalid Yousif, Mandeep Sandhu, Allan Stirling
PURPOSE: The great auricular point (GAP) marks the exit of the great auricular nerve at the posterior border of the sternocleidomastoid muscle (SCM). It is a key landmark for the identification of the spinal accessory nerve, and its intraoperative localization is vital to avoid neurological sequelae. This study delineates the topography and surface anatomy landmarks that used to localize the GAP. METHODS: Thirty cadaveric heminecks were dissected on a layer-by-layer approach...
October 15, 2016: Surgical and Radiologic Anatomy: SRA
S D Stites, C A Cooblall, J Aronovitz, S B Singletary, K Micklow, M Sjeime
BACKGROUND: The incidence and severity of Clostridium difficile infection (CDI) have increased in recent years. Predictive models may help to identify at-risk patients before the onset of infection. Early identification of high-risk patients could help antimicrobial stewardship (AMS) programmes and other initiatives to better prevent C. difficile in these patients. AIM: To develop a predictive model that identifies patients at high risk for CDI at the time of hospitalization...
August 24, 2016: Journal of Hospital Infection
Lara A Coelho, Giovanna Zaninelli, Claudia L R Gonzalez
Previous research has found that the perception of our hands is inaccurate. This distorted representation has several constant characteristics including an overestimation of hand width and an underestimation of finger length. In this study, we further investigate this phenomenon by exploring the boundaries of hand representation. Participants placed one hand underneath a table top so it was occluded from view. Using their free hand, participants were instructed to point to the location where they believed the tips and bases of each of their fingers were...
October 13, 2016: Psychological Research
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