WorldWideScience

Sample records for sun-earth connection studies

  1. Sun-Earth Day Connects History, Culture and Science

    Science.gov (United States)

    Cline, T.; Thieman, J.

    2003-12-01

    The NASA Sun-Earth Connection Education forum annually promotes and event called Sun-Earth Day: a national celebration of the Sun, the space around the Earth (geospace), and how all of it affects life on our planet. For the past 3 years this event has provided a venue by which classrooms, museums, planetaria, and at NASA centers have had a sensational time sharing stories, images, and activities related to the Sun-Earth connections and the views o fthe Sun from Earth. Each year we select a different theme by which NASA Space Science can be further related to cross-curricular activities. Sun-Earth Day 2002, "Celebrate the Equinox", drew parallels between Native American Cultures and NASA's Sun-Earth Connection research via cultural stories, interviews, web links, activities and Native American participation. Sun-Earth Day 2003, "Live From the Aurora", shared the beauty of the Aurora through a variety of activities and stories related to perspectives of Northern Peoples. Sun-Earth Day 2004 will share the excitement of the transit of Venus through comparisons of Venus with Earth and Mars, calculations of the distances to nearby stars, and the use of transits to identify extra-solar planets. Finally, Sun-Earth Day 2005 will bring several of these themes together by turning our focus to the history and culture surrounding ancient observatories such as Chaco Canyon, Machu Picchu, and Chichen Itza.

  2. Sun-earth connection education through modern views of ancient

    Science.gov (United States)

    Thieman, J. R.

    The NASA Sun-Earth Connection Education Forum (SECEF) has the responsibility of using the latest science results from the study of solar physics, space physics, and aeronomy to inspire students in the classroom and to inform the public in general. SECEF works with NASA's Sun-Earth Connection spaceflight missions to accomplish this goal. Each year the missions and SECEF combine to promote their science through a major event designed to attract the attention of all. In late 2004 and 2005 the event will be the study of solar observatories created by ancient peoples and a comparison of their knowledge and culture to present understanding. Two solar observatory sites will be featured, Chaco Canyon in the U.S. and Chichen Itza in Mexico. There are many other places throughout the world that could also be featured as solar observatories and some of these may be described on the SECEF web site or used in future occurrences. Special emphasis is placed on events associated with the solstice and equinox dates. It is hoped that there will be happenings around the world on these days and SECEF will work with many museums, science centers, and other groups to help make this happen. Plans for the 2005 Ancient Observatories event and possible future events on the same subject will be described.

  3. Sun-Earth Connection EPO's with Multiple Uses and Audiences

    Science.gov (United States)

    Foster, S. Q.; Johnson, R. M.; Russell, R.; Lu, G.; Richmond, A.; Maute, A.; Haller, D.; Conery, C.; Bintner, G.; Kiessling, D.; Hughes, W. J.

    2005-05-01

    The three-year life of an EPO grant can be a journey guided by clear goals and enriched by collaborative and outreach opportunities connecting Space sciences to Earth sciences for both K-12 and public audiences. This point is illustrated by two EPO projects funded by NASA Sun-Earth Connection research grants to the High Altitude Observatory (HAO) at the National Center for Atmospheric Research. They are entering their final year coordinated by the Office of Education and Outreach at University Corporation for Atmospheric Research. The content focus of both projects is well aligned with HAO's research mission and the expertise of our scientists, addressing solar dynamics, space weather, and the impacts of solar events on the magnetosphere, as well as societies inhabiting Earth's surface. The first project (Gang Lu, PI) develops presentation resources, inquiry activities, and tips that will help HAO scientists be better prepared to visit K-12 classrooms. Unexpectedly, the simultaneous development of a Teachers' Guide to NCAR's new Climate Discovery exhibit, which takes an Earth system approach to climate and global change, has created a niche for this EPO resource to be revised and repurposed for a needed unit in the guide about the exhibit's graphic panels on Sun-Earth connections. The second project (Art Richmond, PI) engages two high school "Teachers in Residence" to develop resources they can utilize with their students. Excited by exceptional educational graphics and animations in the new Physics of the Aurora: Earth Systems module co-produced by HAO and the COMET Program for advanced undergraduate courses, they chose to adapt appropriate sections of the module to enrich Earth science and math concepts addressed in their 9th and 10th grade astronomy and general physics classes. Simultaneously, the Windows to the Universe web site, which continuously updates space science content and is now developing a new Space Weather section with support from the Center for

  4. A Full Study on the Sun-Earth Connection of an Earth-Directed CME Magnetic Flux Rope

    CERN Document Server

    Vemareddy, P

    2015-01-01

    We present an investigation of an eruption event of coronal mass ejection (CME) magnetic flux rope (MFR) from source active region (AR) NOAA 11719 on 11 April 2013 utilizing observations from SDO, STEREO, SOHO, and WIND spacecraft. The source AR consists of pre-existing sigmoidal structure stacked over a filament channel which is regarded as MFR system. EUV observations of low corona suggest a further development of this MFR system by added axial flux through tether-cutting reconnection of loops at the middle of sigmoid under the influence of continuous slow flux motions during past two days. Our study implies that the MFR system in the AR is initiated to upward motion by kink-instability and further driven by torus-instability. The CME morphology, captured in simultaneous three-point coronagraph observations, is fitted with Graduated Cylindrical Shell (GCS) model and discerns an MFR topology with orientation aligning with magnetic neutral line in the source AR. This MFR expands self-similarly and is found to...

  5. High-Performance Data Analysis Tools for Sun-Earth Connection Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Interactive Data Language (IDL) is a standard tool used by many researchers in observational fields. Present day Sun-Earth Connection missions like SOHO, or...

  6. Sun-Earth Days

    Science.gov (United States)

    Thieman, J.; Ng, C.; Lewis, E.; Cline, T.

    2010-08-01

    Sun-Earth Day is a well-coordinated series of programs, resources and events under a unique yearly theme highlighting the fundamentals of heliophysics research and missions. A menu of activities, conducted throughout the year, inspire and educate participants. Sun-Earth Day itself can vary in date, but usually is identified by a celebration on or near the spring equinox. Through the Sun-Earth Day framework we have been able to offer a series of coordinated events that promote and highlight the Sun, its connection to Earth and the other planets. Sun-Earth Day events are hosted by educators, museums, amateur astronomers and scientists and occur at schools, community groups, parks, planetaria and science centers around the globe. Sun-Earth Day raises the awareness and knowledge of formal and informal education audiences concerning space weather and heliophysics. By building on the success of Sun-Earth Day yearly celebrations, we seek to affect people of all backgrounds and ages with the wonders of heliophysics science, discovery, and exploration in ways that are both tangible and meaningful to their lives.

  7. ITM-Related Data and Model Services at the Sun Earth Connection Active Archive (SECAA)

    Science.gov (United States)

    McGuire, R.; Bilitza, D.; Kovalick, T.; Papitashvili, N.; Candey, R.; Han, D.

    2004-12-01

    NASA's Sun Earth Connection Active Archive (SECAA) provides access to a large volume of data and models that are of relevance to Ionospheric, Thermospheric and Mesospheric (ITM) physics. SECAA has developed a number of web systems to facilitate user access to this important data source and is making these services available through Web Services (or Application Programming Interfaces, API) directly to applications such as VxOs. The Coordinated Data Analysis web (CDAWeb) lets user plot data using a wide range of parameter display options including mapped images and movies. Capabilities also include parameter listings and data downloads in CDF and ASCII format. CDAWeb provides access to data from most of NASA's currently operating space science satellites and many of the earlier missions; of special ITM interest are DE-2, ISIS, FAST, Equator-S, and TIMED. SECAA maintains and supports the Common Data Format (CDF) including software to read and write CDF files. Most recently translator services have been added for CDF translations to/from netCDF, FITS, CDFXML, and ASCII. The SSCWeb interface enables users to plot orbits for the majority of space physics satellites (including TIMED, UARS, DMSP, NOAA, LANL etc.) and to query for magnetic field line conjunctions between multiple spacecraft and ground stations and for magnetic region occupancy. Recently an Interactive 3-D orbit viewer was added to SSCWeb. Access to legacy data from older ITM satellite missions is provided through the ATMOWeb system with the ability to generate plots and download data subsets in ASCII format. Recently added capabilities include the option to filter the data using an upper and lower boundary for any one of the data set parameters. We will also present the newest version of the web portal to SECAA's models catalog, ftp archive, and web interfaces. The web interfaces (Fortran, C, Java) let users compute, list, plot, and download model parameters for selected models (IRI, IGRF, MSIS/CIRA, AE

  8. High-Performance Data Analysis Tools for Sun-Earth Connection Missions

    Science.gov (United States)

    Messmer, Peter

    2011-01-01

    The data analysis tool of choice for many Sun-Earth Connection missions is the Interactive Data Language (IDL) by ITT VIS. The increasing amount of data produced by these missions and the increasing complexity of image processing algorithms requires access to higher computing power. Parallel computing is a cost-effective way to increase the speed of computation, but algorithms oftentimes have to be modified to take advantage of parallel systems. Enhancing IDL to work on clusters gives scientists access to increased performance in a familiar programming environment. The goal of this project was to enable IDL applications to benefit from both computing clusters as well as graphics processing units (GPUs) for accelerating data analysis tasks. The tool suite developed in this project enables scientists now to solve demanding data analysis problems in IDL that previously required specialized software, and it allows them to be solved orders of magnitude faster than on conventional PCs. The tool suite consists of three components: (1) TaskDL, a software tool that simplifies the creation and management of task farms, collections of tasks that can be processed independently and require only small amounts of data communication; (2) mpiDL, a tool that allows IDL developers to use the Message Passing Interface (MPI) inside IDL for problems that require large amounts of data to be exchanged among multiple processors; and (3) GPULib, a tool that simplifies the use of GPUs as mathematical coprocessors from within IDL. mpiDL is unique in its support for the full MPI standard and its support of a broad range of MPI implementations. GPULib is unique in enabling users to take advantage of an inexpensive piece of hardware, possibly already installed in their computer, and achieve orders of magnitude faster execution time for numerically complex algorithms. TaskDL enables the simple setup and management of task farms on compute clusters. The products developed in this project have the

  9. Sun-earth environment study to understand earthquake prediction

    Science.gov (United States)

    Mukherjee, S.

    2007-05-01

    Earthquake prediction is possible by looking into the location of active sunspots before it harbours energy towards earth. Earth is a restless planet the restlessness turns deadly occasionally. Of all natural hazards, earthquakes are the most feared. For centuries scientists working in seismically active regions have noted premonitory signals. Changes in thermosphere, Ionosphere, atmosphere and hydrosphere are noted before the changes in geosphere. The historical records talk of changes of the water level in wells, of strange weather, of ground-hugging fog, of unusual behaviour of animals (due to change in magnetic field of the earth) that seem to feel the approach of a major earthquake. With the advent of modern science and technology the understanding of these pre-earthquake signals has become stronger enough to develop a methodology of earthquake prediction. A correlation of earth directed coronal mass ejection (CME) from the active sunspots has been possible to develop as a precursor of the earthquake. Occasional local magnetic field and planetary indices (Kp values) changes in the lower atmosphere that is accompanied by the formation of haze and a reduction of moisture in the air. Large patches, often tens to hundreds of thousands of square kilometres in size, seen in night-time infrared satellite images where the land surface temperature seems to fluctuate rapidly. Perturbations in the ionosphere at 90 - 120 km altitude have been observed before the occurrence of earthquakes. These changes affect the transmission of radio waves and a radio black out has been observed due to CME. Another heliophysical parameter Electron flux (Eflux) has been monitored before the occurrence of the earthquakes. More than hundreds of case studies show that before the occurrence of the earthquakes the atmospheric temperature increases and suddenly drops before the occurrence of the earthquakes. These changes are being monitored by using Sun Observatory Heliospheric observatory

  10. NASA Sun-Earth Connections Theory Program: The Structure and Dynamics of the Solar Corona and Inner Heliosphere

    Science.gov (United States)

    Mikic, Zoran; Grebowsky, Joseph M. (Technical Monitor)

    2001-01-01

    This report covers technical progress during the fourth quarter of the second year of NASA Sun-Earth Connections Theory Program (SECTP) contract 'The Structure and Dynamics of the Solar Corona and Inner Heliosphere,' NAS5-99188, between NASA and Science Applications International Corporation, and covers the period May 16,2001 to August 15, 2001. Under this contract SAIC and the University of California, Irvine (UCI) have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model.

  11. The Real Reasons for Seasons--Sun-Earth Connections: Unraveling Misconceptions about the Earth and Sun. Grades 6-8. Teacher's Guide. LHS GEMS.

    Science.gov (United States)

    Gould, Alan; Willard, Carolyn; Pompea, Stephen

    This guide is aimed at helping students arrive at a clear understanding of seasons as they investigate the connections between the sun and the earth. Activities include: (1) "Name the Season"; (2) "Sun-Earth Survey"; (3) "Trip to the Sun"; (4) "What Shape is Earth's Orbit?"; (5) "Temperatures around the…

  12. High-Performance Data Analysis Tools for Sun-Earth Connection Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Interactive Data Language (IDL) is a standard tool used by many researchers in observational fields. Present day Sun-Earch Connection missions like RHESSI or...

  13. Sun, Earth and Sky

    CERN Document Server

    Lang, Kenneth R

    2006-01-01

    This Second Edition of Sun, Earth and Sky updates the popular text by providing comprehensive accounts of the most recent discoveries made by five modern solar spacecraft during the past decade. Their instruments have used sound waves to peer deep into the Sun’s inner regions and measure the temperature of its central nuclear reactor, and extended our gaze far from the visible Sun to record energetic outbursts that threaten Earth. Breakthrough observations with the underground Sudbury Neutrino Observatory are also included, which explain the new physics of ghostly neutrinos and solve the problematic mismatch between the predicted and observed amounts of solar neutrinos. This new edition of Sun, Earth and Sky also describes our recent understanding of how the Sun’s outer atmosphere is heated to a million degrees, and just where the Sun’s continuous winds come from. As humans we are more intimately linked with our life-sustaining Sun than with any other astronomical object, and the new edition therefore p...

  14. The Spanish Space Weather Service SeNMEs. A Case Study on the Sun-Earth Chain

    Science.gov (United States)

    Palacios, J.; Cid, C.; Guerrero, A.; Saiz, E.; Cerrato, Y.; Rodríguez-Bouza, M.; Rodríguez-Bilbao, I.; Herraiz, M.; Rodríguez-Caderot, G.

    2016-04-01

    The Spanish Space Weather Service SeNMEs, www.senmes.es, is a portal created by the SRG-SW of the Universidad de Alcalá, Spain, to meet societal needs of near real-time space weather services. This webpage-portal is divided in different sections to fulfill users needs about space weather effects: radio blackouts, solar energetic particle events, geomagnetic storms and presence of geomagnetically induced currents. In less than one year of activity, this service has released a daily report concerning the solar current status and interplanetary medium, informing about the chances of a solar perturbation to hit the Earth's environment. There are also two different forecasting tools for geomagnetic storms, and a daily ionospheric map. These tools allow us to nowcast a variety of solar eruptive events and forecast geomagnetic storms and their recovery, including a new local geomagnetic index, LDiñ, along with some specific new scaling. In this paper we also include a case study analysed by SeNMEs. Using different high resolution and cadence data from space-borne solar telescopes SDO, SOHO and GOES, along with ionospheric and geomagnetic data, we describe the Sun-Earth feature chain for the event.

  15. Sun-Earth Connections: How the Sun Knocks Out My Cell Phone from 150 Million Kilometers Away

    Science.gov (United States)

    Ladbury, Raymond L.

    2014-01-01

    Large solar particle events (SPE) threaten many elements of critical infrastructure. A 2013 study by Lloyds of London and Atmospheric and Environmental Research recently found that if a worst-case solar event like the 1859 Carrington Event struck our planet now, it could result on $0.6-$2.36 trillion in damages to the economy. In March 2014, researchers Y. D. Liu et al. revealed that just such an event had narrowly missed Earth in July 2012. The event was observed by the STEREO A spacecraft. In this presentation, we examine how the sun can pack such a punch from 150 million km away, the threats such solar particle events pose, their mechanisms and the efforts NASA and other space agencies are carrying out to understand and mitigate such risks.

  16. Sun-Earth Day 2005: Ancient Observatories: Timeless Knowledge

    Science.gov (United States)

    Thieman, J. R.; Cline, T.; Lewis, E.; Hawkins, I.; Odenwald, S.; Mayo, L.

    2005-05-01

    The NASA Sun-Earth Connection Education Forum (SECEF) annually promotes an event called Sun-Earth Day. For Sun-Earth Day 2005 SECEF has selected a theme called "Ancient Observatories: Timeless Knowledge. This year's Sun-Earth Day theme is your ticket to a fascinating journey through time as we explore centuries of sun watching by a great variety of cultures. From ancient solar motion tracking to modern solar activity monitoring the Sun has always occupied an important spot in mankind's quest to understand the Universe. Sun-Earth Day events usually are centered on the spring equinox around March 21, but this year there has already been a webcast from the San Francisco Exploratorium and the Native American ruins at Chaco Canyon, New Mexico on the day of winter solstice 2004. There will be another webcast on March 20 live from Chichen Itza, Mexico highlighting the solar alignment that makes a serpent appear on one of the ancient pyramids. The website http://sunearthday.nasa.gov has been developed to provide the necessary resources and opportunities for participation by scientists and educators in giving school or general public programs about Sun-Earth Day. The goal is to involve as much of the student population and the public in this event as possible and to help them understand the importance of the Sun for ancient and modern peoples. Through engaging activities available on the website, classrooms and museums can create their own event or participate in one of the opportunities we make available. Scientists, educators, amateur astronomers, and museums are invited to register on the website to receive a free packet of materials about Sun-Earth Day for use in making presentations or programs about the event. Past and future Sun-Earth Days will be discussed as well.

  17. Sun-Earth Day - Teaching Heliophysics Through Education Technology

    Science.gov (United States)

    Thieman, J.; Cline, T.; Lewis, E.

    2010-01-01

    Sun-Earth Day (SED) is an Education and Outreach program supported by the U.S, National Aeronautics and Space Administration (NASA). The intent of the program is to teach students and the general public about Heliophysics (the science of the study of the Sun, how it varies, and how solar dynamics affect the rest of the solar system, especially the Earth). The program was begun ten years ago. Each year since that time a particular day has been designated as "Sun-Earth Day ,,. Usually the day of the spring equinox (March 20 or 21) is Sun-Earth Day, but other days have been used as well. Each year a theme is chosen relating to Heliophysics and events reflecting that theme are planned not only for Sun-Earth Day, but for the entire year. From the very beginning educational technology was emphasized in the events in order to effectively reach wide audiences with the SED message. The main approach has been to have a "webcast" related to each year's theme, often from a location that supports the theme as well. For example, a webcast took place from the Mayan pyramids at Chichen Itza, Mexico to highlight the theme of "Ancient Observatories, Timeless Knowledge". Webcasts were not the only technology employed, however. Many of the themes centered on the dynamic nature of the Sun and the effects that solar storms can have on interplanetary space and in our day-to-day life on Earth. Activities for tracking when solar storms happen and how they affect the Earth were developed and brought together in an educational package called Space Weather Action Centers. This project is explained in more detail in another presentation in this session being given by Norma Teresinha Oliveira Reis. Recent Sun-Earth Days have utilized "social networking" technologies to reach widespread groups on the internet. Podcasts, Vodcasts, Facebook, Twitter, and Second Life are the types of network technologies being employed now. The NASA Distance learning Network is another method for bringing Sun-Earth

  18. Sun-Earth Day: Growth and Impact of NASA E/PO Program

    Science.gov (United States)

    Hawkins, I.; Thieman, J.

    2004-12-01

    Over the past six years, the NASA Sun-Earth Connection Education Forum has sponsored and coordinated education public outreach events to highlight NASA Sun-Earth Connection research and discoveries. Our strategy involves using celestial phenomena, such as total solar eclipses and the Transit of Venus to celebrate Sun-Earth Day, a popular Education and Public Outreach international program. Sun-Earth Day also focuses attention on Equinoxes and Solstices to engage K-12 schools and the general public in space science activities, demonstrations, and interactions with space scientists. In collaboration with partners that include the Exploratorium, Maryland Science Center, NASA Connect, Sun-Earth Connection missions, Ideum, and others, we produce webcasts, other multi-media, and print resources for use by school and informal educators nation-wide. We provide training and professional development to K-12 educators, museum personnel, amateur astronomers, Girl Scout leaders, etc., so they can implement their own outreach programs taking advantage of our resources. A coordinated approach promotes multiple programs occurring each year under a common theme. We will report lessons learned from several years of experience, and strategies for growth and sustainability. We will also share our plans for "Ancient Observatories - Timeless Knowledge" our theme for Sun-Earth Day 2005, which will feature solar alignments at ancient sites that mark the equinoxes and/or solstices. The video and webcast programming will feature several sites including: Chaco Canyon (New Mexico), Hovenweep (Utah), and Chichen Itza (Mexico). Many of these sites present unique opportunities to develop authentic cultural connections to Native Americans, highlighting the importance of the Sun across the ages.

  19. Earth-Affecting Solar Causes Observatory (EASCO): a mission at the Sun-Earth L5

    DEFF Research Database (Denmark)

    Gopalswamy, Nat; Davila, Joseph M.; Auchère, Frédéric

    2011-01-01

    . The Earth-Affecting Solar Causes Observatory (EASCO) is a proposed mission to be located at the Sun-Earth L5 that overcomes these deficiencies. The mission concept was recently studied at the Mission Design Laboratory (MDL), NASA Goddard Space Flight Center, to see how the mission can be implemented...

  20. The Maunder minimum and the variable sun-earth connection

    CERN Document Server

    Wei Hock Soon, Willie

    2003-01-01

    This book takes an excursion through solar science, science history, and geoclimate with a husband and wife team who revealed some of our sun's most stubborn secrets. E Walter and Annie S D Maunder's work helped in understanding our sun's chemical, electromagnetic and plasma properties. They knew the sun's sunspot migration patterns and its variable, climate-affecting, inactive and active states in short and long time frames. An inactive solar period starting in the mid-seventeenth century lasted approximately seventy years, one that E Walter Maunder worked hard to make us understand: the Maun

  1. International Sun-Earth Explorer (ISEE)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    Series of three US satellites designed to study the solar wind and its interaction with the Earth's magnetosphere. ISEE-1 and 2 were placed into highly elliptical Earth orbits. ISEE-3 was placed in a halo orbit at the L1 Lagrangian point between the Sun and Earth. It gave advance warning of solar storms heading towards Earth. (See also INTERNATIONAL COMETARY EXPLORER and EXPLORER.)...

  2. Capturing small asteroids into a Sun-Earth Lagrangian point

    Science.gov (United States)

    Lladó, Neus; Ren, Yuan; Masdemont, Josep J.; Gómez, Gerard

    2014-02-01

    In this paper we address the feasibility of capturing small Near-Earth Asteroids (NEAs) into the vicinity of the Sun-Earth L2 libration point using a continuous-thrust propulsion system assumed to be attached to the asteroid. The vicinity of this libration point is a gateway to the Earth-Moon neighborhood and using it for capture, or for transit, small NEAs could be interesting for mining or science purposes.

  3. Capturing small asteroids into Sun-Earth Lagrangian points for mining purposes

    OpenAIRE

    Lladó, Neus; Ren, Yuan; Masdemont Soler, Josep; Gomez Muntaner, Gerard

    2012-01-01

    The aim of this paper is to study the capture of small Near Earth Objects (NEOs) into the Sun-Earth L2 using low-thrust propulsion for mining or science purposes. As it is well known, the vicinity of these points is inside a net of dynamical channels suitable for the transport in the Earth-Moon neighborhood, so different final destinations from here could be easily considered. Asteroids with very small mass and not representing a potential hazard are analyzed. An initial pruning o...

  4. Phasing Delta-V for transfers from Sun-Earth halo orbits to the Moon

    Science.gov (United States)

    Chen, Hongru; Kawakatsu, Yasuhiro; Hanada, Toshiya

    2016-10-01

    Inspired by successful extended missions such as the ISEE-3, an investigation for the extended mission that involves a lunar encounter following a Sun-Earth halo orbit mission is considered valuable. Most previous studies present the orbit-to-orbit transfers where the lunar phase is not considered. Intended for extended missions, the present work aims to solve for the minimum phasing ∆V for various initial lunar phases. Due to the solution multiplicity of the two-point boundary value problem, the general constrained optimization algorithm that does not identify multiple feasible solutions is shown to miss minima. A two-step differential corrector with a two-body Lambert solver is developed for identifying multiple solutions. The minimum ∆V associated with the short-way and long-way approaches can be recovered. It is acquired that the required ∆V to cover all initial lunar phases is around 45 m/s for the halo orbit with out-of-plane amplitude Az greater than 3.5×105 km, and 14 m/s for a small halo orbit with Az=1×105 km. In addition, the paper discusses the phasing planning based on the ∆V result and the shift of lunar phase with halo orbit revolution.

  5. Optimal Sunshade Configurations for Space-Based Geoengineering near the Sun-Earth L1 Point.

    Directory of Open Access Journals (Sweden)

    Joan-Pau Sánchez

    Full Text Available Within the context of anthropogenic climate change, but also considering the Earth's natural climate variability, this paper explores the speculative possibility of large-scale active control of the Earth's radiative forcing. In particular, the paper revisits the concept of deploying a large sunshade or occulting disk at a static position near the Sun-Earth L1 Lagrange equilibrium point. Among the solar radiation management methods that have been proposed thus far, space-based concepts are generally seen as the least timely, albeit also as one of the most efficient. Large occulting structures could potentially offset all of the global mean temperature increase due to greenhouse gas emissions. This paper investigates optimal configurations of orbiting occulting disks that not only offset a global temperature increase, but also mitigate regional differences such as latitudinal and seasonal difference of monthly mean temperature. A globally resolved energy balance model is used to provide insights into the coupling between the motion of the occulting disks and the Earth's climate. This allows us to revise previous studies, but also, for the first time, to search for families of orbits that improve the efficiency of occulting disks at offsetting climate change on both global and regional scales. Although natural orbits exist near the L1 equilibrium point, their period does not match that required for geoengineering purposes, thus forced orbits were designed that require small changes to the disk attitude in order to control its motion. Finally, configurations of two occulting disks are presented which provide the same shading area as previously published studies, but achieve reductions of residual latitudinal and seasonal temperature changes.

  6. Optimal Sunshade Configurations for Space-Based Geoengineering near the Sun-Earth L1 Point.

    Science.gov (United States)

    Sánchez, Joan-Pau; McInnes, Colin R

    2015-01-01

    Within the context of anthropogenic climate change, but also considering the Earth's natural climate variability, this paper explores the speculative possibility of large-scale active control of the Earth's radiative forcing. In particular, the paper revisits the concept of deploying a large sunshade or occulting disk at a static position near the Sun-Earth L1 Lagrange equilibrium point. Among the solar radiation management methods that have been proposed thus far, space-based concepts are generally seen as the least timely, albeit also as one of the most efficient. Large occulting structures could potentially offset all of the global mean temperature increase due to greenhouse gas emissions. This paper investigates optimal configurations of orbiting occulting disks that not only offset a global temperature increase, but also mitigate regional differences such as latitudinal and seasonal difference of monthly mean temperature. A globally resolved energy balance model is used to provide insights into the coupling between the motion of the occulting disks and the Earth's climate. This allows us to revise previous studies, but also, for the first time, to search for families of orbits that improve the efficiency of occulting disks at offsetting climate change on both global and regional scales. Although natural orbits exist near the L1 equilibrium point, their period does not match that required for geoengineering purposes, thus forced orbits were designed that require small changes to the disk attitude in order to control its motion. Finally, configurations of two occulting disks are presented which provide the same shading area as previously published studies, but achieve reductions of residual latitudinal and seasonal temperature changes.

  7. Orbit Determination Error Analysis Results for the Triana Sun-Earth L2 Libration Point Mission

    Science.gov (United States)

    Marr, G.

    2003-01-01

    Using the NASA Goddard Space Flight Center's Orbit Determination Error Analysis System (ODEAS), orbit determination error analysis results are presented for all phases of the Triana Sun-Earth L1 libration point mission and for the science data collection phase of a future Sun-Earth L2 libration point mission. The Triana spacecraft was nominally to be released by the Space Shuttle in a low Earth orbit, and this analysis focuses on that scenario. From the release orbit a transfer trajectory insertion (TTI) maneuver performed using a solid stage would increase the velocity be approximately 3.1 km/sec sending Triana on a direct trajectory to its mission orbit. The Triana mission orbit is a Sun-Earth L1 Lissajous orbit with a Sun-Earth-vehicle (SEV) angle between 4.0 and 15.0 degrees, which would be achieved after a Lissajous orbit insertion (LOI) maneuver at approximately launch plus 6 months. Because Triana was to be launched by the Space Shuttle, TTI could potentially occur over a 16 orbit range from low Earth orbit. This analysis was performed assuming TTI was performed from a low Earth orbit with an inclination of 28.5 degrees and assuming support from a combination of three Deep Space Network (DSN) stations, Goldstone, Canberra, and Madrid and four commercial Universal Space Network (USN) stations, Alaska, Hawaii, Perth, and Santiago. These ground stations would provide coherent two-way range and range rate tracking data usable for orbit determination. Larger range and range rate errors were assumed for the USN stations. Nominally, DSN support would end at TTI+144 hours assuming there were no USN problems. Post-TTI coverage for a range of TTI longitudes for a given nominal trajectory case were analyzed. The orbit determination error analysis after the first correction maneuver would be generally applicable to any libration point mission utilizing a direct trajectory.

  8. Sun-Earth Day: Reaching the Education Audience by Informal Means

    Science.gov (United States)

    Thieman, J.; Lewis, E.; Cline, T.

    2010-01-01

    For ten years the Sun-Earth Day program has promoted Heliophysics education to ever larger audiences through events centered on attractive annual themes. What originally started out as a one day event quickly evolved into a series of programs and events that occur throughout the year culminating with a celebration on or near the Spring Equinox. The events are often formal broadcasts or webcasts seeking to convey the science behind the latest solar-terrestrial mission discoveries. This has been quite successful, but it is clear that the younger generation increasingly depends on social networking approaches and informal news transmission for learning what is happening in the world around them. For 2010, the Sun-Earth Day team put emphasis on using informal approaches to bring the theme to the audience. The main event, a webcast from the NASA booth at the National Science Teachers Association (NSTA) annual meeting by the NASA EDGE group, took a lighthearted and offbeat approach to interviewing scientists and educators about Heliophysics news. NASA EDGE programs are unscripted and unpredictable, and that represents a different approach to getting the message across. The webcast was supplemented by a number of social networking avenues. The Sun-Earth Day program explored a wide range of social media applications including Facebook, Twitter, NING, podcasting, iPhone apps, etc. Each of these offers unique and effective methods to promote Heliophysics content and mission related highlights. The facebook site was quite popular and message posting there told the Sun-Earth Day story piece by piece. The same could be said of twittering and the tweetup held at the NSTA site. Has all of this been effective? Results are still being gathered, but anecdotal responses from the world seem very positive. What other methods might be used in the future to bring the science to a personal hands-on, interactive experience? Outcomes: Participants will: (1) Be introduced to the Sun-Earth

  9. Minimum time solar sailing from geosynchronous orbit to the sun-earth L2 point

    Science.gov (United States)

    Hur, Sun H.; Bryson, Arthur E., Jr.

    1992-08-01

    An approximate time-optimal of a solar sail from a geosynchronous orbit to the sun-earth L2 libration point is found using a combined method of local optimization and single shooting. The local optimization strategy is based on maximizing the time rate of change of an energy variable at each time. This strategy overcomes the numerical difficulties associated with solving optimal control problems of long duration like the solar sail transfer problem. The single shooting portion of the method is employed to meet the terminal constraints. The combined method can be applied to other optimal low thrust transfer problems of long duration.

  10. Climate and weather of the Sun-Earth system (CAWSES) highlights from a priority program

    CERN Document Server

    Lübken, Franz-Josef

    2012-01-01

    CAWSES (Climate and Weather of the Sun-Earth System) is the most important scientific program of SCOSTEP (Scientific Committee on Solar-Terrestrial Physics). CAWSES has triggered a scientific priority program within the German Research Foundation for a period of 6 years. Approximately 30 scientific institutes and 120 scientists were involved in Germany with strong links to international partners. The priority program focuses on solar influence on climate, atmospheric coupling processes, and space climatology. This book summarizes the most important results from this program covering some impor

  11. Colorado Lights: Exploring the Sun-Earth Connection through Art and Writing

    Science.gov (United States)

    Possel, T.; Cobabe-Ammann, E.; Wood, E.; Becker, K.

    2007-12-01

    Over the last decade, it has become increasingly clear that science can be an important way to excite children about reading, writing and the arts. The natural beauty that science represents inspires students to both think about the world around them and strive to find the words and images that communicate their excitement. Colorado Lights is a new program that provides a set of five activities for students in Grades 3 through 5 to explore the beauty, science and mythology of the aurora creatively through art and writing. This standards-based, flexible 'plug-and-play' program is based on the latest research on bringing science into the literacy and art classroom. It can be used as a complete sequence of lessons or can be used as guidelines for teachers to develop their own activities.

  12. Orbit Determination (OD) Error Analysis Results for the Triana Sun-Earth L1 Libration Point Mission and for the Fourier Kelvin Stellar Interferometer (FKSI) Sun-Earth L2 Libration Point Mission Concept

    Science.gov (United States)

    Marr, Greg C.

    2003-01-01

    The Triana spacecraft was designed to be launched by the Space Shuttle. The nominal Triana mission orbit will be a Sun-Earth L1 libration point orbit. Using the NASA Goddard Space Flight Center's Orbit Determination Error Analysis System (ODEAS), orbit determination (OD) error analysis results are presented for all phases of the Triana mission from the first correction maneuver through approximately launch plus 6 months. Results are also presented for the science data collection phase of the Fourier Kelvin Stellar Interferometer Sun-Earth L2 libration point mission concept with momentum unloading thrust perturbations during the tracking arc. The Triana analysis includes extensive analysis of an initial short arc orbit determination solution and results using both Deep Space Network (DSN) and commercial Universal Space Network (USN) statistics. These results could be utilized in support of future Sun-Earth libration point missions.

  13. Understanding the Sun-Earth Libration Point Orbit Formation Flying Challenges For WFIRST and Starshade

    Science.gov (United States)

    Webster, Cassandra M.; Folta, David C.

    2017-01-01

    In order to fly an occulter in formation with a telescope at the Sun-Earth L2 (SEL2) Libration Point, one must have a detailed understanding of the dy-namics that govern the restricted three body system. For initial purposes, a linear approximation is satisfactory, but operations will require a high-fidelity modeling tool along with strategic targeting methods in order to be successful. This paper focuses on the challenging dynamics of the transfer trajectories to achieve the relative positioning of two spacecraft to fly in formation at SEL2, in our case, the Wide-Field Infrared Survey Telescope (WFIRST) and a proposed Starshade. By modeling the formation transfers using a high fidelity tool, an accurate V approximation can be made to as-sist with the development of the subsystem design required for a WFIRST and Starshade formation flight mission.

  14. Solar radiation pressure used for formation flying control around the Sun-Earth libration point

    Institute of Scientific and Technical Information of China (English)

    Sheng-ping GONG; Jun-feng LI; He-xi BAOYIN

    2009-01-01

    Solar radiation pressure is used to control the formation flying around the L2 libration point in the Sun-Earth system. Formation flying control around a halo orbit requires a very small thrust that cannot be satisfied by the latest thrusters. The key contribution of this paper is that the continuous low thrust is produced by solar radiation pressure to achieve the tight formation flying around the libration point. However, only certain families of formation types can be controlled by solar radiation pressure since the direction of solar radiation pressure is restricted to a certain range. Two types of feasible formations using solar radiation pressure control are designed. The conditions of feasible formations are given analytically. Simulations are presented for each case, and the results show that the formations are well controlled by solar radiation pressure.

  15. CHANG'E-2 lunar escape maneuvers to the Sun-Earth L2 libration point mission

    Science.gov (United States)

    Liu, Lei; Liu, Yong; Cao, Jianfeng; Hu, Songjie; Tang, Geshi; Xie, Jianfeng

    2014-01-01

    This paper addresses lunar escape maneuvers of the first Chinese Sun-Earth L2 libration point mission by the CHANG'E-2 satellite, which is also the world's first satellite to reach the L2 point from a lunar orbit. The lunar escape maneuvers are heavily constrained by the remaining propellant and the condition of telemetry, track and command, among others. First, these constraints are analyzed and summarized to design a target L2 Lissajous orbit and an initial transfer trajectory. Second, the maneuver mathematical models are studied. The multilevel maneuver schemes which consist of phasing maneuvers and a final lunar escape maneuver are designed for actual operations. Based on the scheme analysis and comparison, the 2-maneuver scheme with a 5.3-h-period phasing orbit is ultimately selected. Finally, the mission status based on the scheme is presented and the control operation results are discussed in detail. The methodology in this paper is especially beneficial and applicable to a future multi-mission instance in the deep space exploration.

  16. NEACP Onboard Connectivity Study

    Science.gov (United States)

    1990-03-30

    Methodology Framework .............................. 6-3 6.2.2 Sources of ME Cost Savings with NOCH ............... 6-5 6.2.3 Additional Benefits of 1OCU...processing system (MPS) installation connects all record and data communications equipment to a common MIL -STD-1553B bus and automates many of the manual...Local Area Network Concepts A NOCH developed around a generic bus would provide connectivity throughout the aircraft, thereby reducing or eliminating

  17. Formation Flying Satellite Control Around the L2 Sun-Earth Libration Point

    Science.gov (United States)

    Hamilton, Nicholas H.

    2001-12-01

    A growing interest in formation flying satellites demands development and analysis of control and estimation algorithms for station-keeping and formation maneuvering. This thesis discusses the development of a discrete linear-quadratic- regulator control algorithm for formations in the vicinity of the L2 sun-earth libration point. The development of an appropriate Kalman filter is included as well. Simulations are created for the analysis of the station-keeping and various formation maneuvers of the Stellar Imager mission. The simulations provide tracking error, estimation error, and control effort results. From the control effort, useful design parameters such as AV and propellant mass are determined. For formation maneuvering, the drone spacecraft track to within 4 meters of their desired position and within 1.3 millimeters per second of their desired zero velocity. The filter, with few exceptions, keeps the estimation errors within their three-sigma values. Without noise, the controller performs extremely well, with the drones tracking to within several micrometers. Bach drone uses around 1 to 2 grams of propellant per maneuver, depending on the circumstances.

  18. Visualizing Sun-Earth-Moon Relationships through Hands-On Modeling

    Science.gov (United States)

    Morton, Abby

    2013-04-01

    "Tell me and I forget, teach me and I may remember, involve me and I learn." -Benjamin Franklin Understanding the spatial relationships between the sun, Earth and Moon is fundamental to any basic earth science education. Since both of the following concepts involve shadows on three-dimensional spheres, seeing them on paper is not often conducive to understanding. In the first activity, students use five Styrofoam balls painted to look like the sun and the four positions of the earth in each season. Students position the Earth-balls in their correct order around the sun and translate what they are seeing onto paper. In the second activity, students hold up a Styrofoam ball painted half white, half black. A picture of the sun is projected at the front of the classroom. They move the ball around their heads as if they were the Earth, keeping the lit side of the moon always facing the sun. They then draw the phases of the moon as they see them.

  19. Student Mastery of the Sun-Earth-Moon System in a Flipped Classroom of Pre-service Elementary Education Students

    Science.gov (United States)

    Larsen, Kristine

    2014-01-01

    One of the current trends in pedagogy at all levels(K-college) is the so-called ‘flipped classroom’, in which students prepare for a class meeting through self-study of the material. It is based on a rejection of the classic model of the faculty member as the ‘sage on the stage’ instead, responsibility for learning shifts to the individual student. The faculty member takes on the role of learning facilitator or mentor, and focuses the students’ learning by crafting and administering timely formative assessments (in multiple formats and applied multiple times) that aid both students and the faculty member in tracking the students’ mastery of the learning outcomes. In a flipped, freshman-only, section of SCI 111 Elementary Earth-Physical Sciences (a required introductory science course for pre-service elementary school teachers) the students learned through a combination of individual and group hands-on in-class activities, technology (including PowerPoint presentations and short videos viewed prior to attending class), in-class worksheets, and in-class discussions. Students self-differentiated in how they interacted with the available teaching materials, deciding which activities to spend the most time on based on their individual needs (based on an online quiz taken the night before the class period, and their personal self-confidence with the material). Available in-class activities and worksheets were developed by the faculty member based on student scores on the online quiz as well as personal messages submitted through the course management system the night before the class meeting. While this placed a significant burden on the faculty member in terms of course preparation, it allowed for just-in-time teaching to take place. This poster describes the results of student mastery of content centered on the sun-earth-moon system (specifically seasons, moon phases, and eclipses) as compared to traditional classroom sections.

  20. Early Mission Maneuver Operations for the Deep Space Climate Observatory Sun-Earth L1 Libration Point Mission

    Science.gov (United States)

    Roberts, Craig; Case, Sara; Reagoso, John; Webster, Cassandra

    2015-01-01

    The Deep Space Climate Observatory mission launched on February 11, 2015, and inserted onto a transfer trajectory toward a Lissajous orbit around the Sun-Earth L1 libration point. This paper presents an overview of the baseline transfer orbit and early mission maneuver operations leading up to the start of nominal science orbit operations. In particular, the analysis and performance of the spacecraft insertion, mid-course correction maneuvers, and the deep-space Lissajous orbit insertion maneuvers are discussed, com-paring the baseline orbit with actual mission results and highlighting mission and operations constraints..

  1. Long Term Missions at the Sun-Earth Libration Point L1: ACE, SOHO, and WIND

    Science.gov (United States)

    Roberts, Craig E.

    2011-01-01

    Three heliophysics missions -- the Advanced Composition Explorer (ACE), Solar Heliospheric Observatory (SOHO), and the Global Geoscience WIND -- have been orbiting the Sun-Earth interior libration point L1 continuously since 1997, 1996, and 2004, respectively. ACE and WIND (both NASA missions) and SOHO (an ESA-NASA joint mission) are all operated from the NASA Goddard Space Flight Center (GSFC). While ACE and SOHO have been dedicated libration point orbiters since their launches, WIND has had also a remarkable 10-year career flying a deep-space, multiple lunar-flyby trajectory prior to 2004. That era featured 36 targeted lunar flybys with excursions to both L1 and L2 before its final insertion in L1 orbit. A figure depicts the orbits of the three spacecraft, showing projections of the orbits onto the orthographic planes of a solar rotating ecliptic frame of reference. The SOHO orbit is a quasi-periodic halo orbit, where the frequencies of the in-plane and out-of-plane motions are practically equal. Such an orbit is seen to repeat itself with a period of approximately 178 days. For ACE and WIND, the frequencies of the in-plane and out-of-plane motions are unequal, giving rise to the characteristic Lissajous motion. ACE's orbit is of moderately small amplitude, whereas WIND's orbit is a large-amplitude Lissajous of dimensions close to those of the SOHO halo orbit. As motion about the collinear points is inherently unstable, stationkeeping maneuvers are necessary to prevent orbital decay and eventual escape from the L1 region. Though the three spacecraft are dissimilar (SOHO is a 3-axis stabilized Sun pointer, WIND is a spin-stabilized ecliptic pole pointer, and ACE is also spin-stabilized with its spin axis maintained between 4 and 20 degrees of the Sun), the stationkeeping technique for the three is fundamentally the same. The technique consists of correcting the energy of the orbit via a delta-V directed parallel or anti-parallel to the Spacecraft-to-Sun line. SOHO

  2. Impacts to Electric Power Grid Infrastructures From the Violent Sun-Earth Connection Events of October-November 2003

    Science.gov (United States)

    Kappenman, J. G.

    2004-05-01

    The solar flare activity of October-November 2003 reached historic intensity levels and produced several large Earth-directed CME's that had the potential to cause historically large geomagnetic storms as well. These CME's did cause various geomagnetic storm indices, particularly the regional K and Planetary Kp index, to reach maximum levels for many hours. However, the resulting geomagnetic storms, while causing isolated and important disruptions to power grids, were not of historically large size when considering the rate-of-change of regional geomagnetic fields in many locations. Impacts to power grids are caused by large dB/dt variations in regional geomagnetic fields, in most cases the peak geomagnetic disturbance intensities (in nT/min) were only a fraction of what has occurred during historically large geomagnetic storm events. A review will be provided of the CME passages and features of the passage that drove resulting geomagnetic storm events and impacts to electric power grid infrastructures on October 29-30, 2003. A brief overview of the geomagnetic storm disturbance morphologies and intensities relative to other noteworthy storms will also be provided.

  3. Mission to the Sun-Earth L5 Lagrangian Point: An Optimal Platform for Space Weather Research

    Science.gov (United States)

    Vourlidas, Angelos

    2015-04-01

    The Sun-Earth Lagrangian L5 point is a uniquely advantageous location for space weather research and monitoring. It covers the "birth-to-impact" travel of solar transients; it enables imaging of solar activity at least 3 days prior to a terrestrial viewpoint and measures the solar wind conditions 4-5 days ahead of Earth impact. These observations, especially behind east limb magnetograms, will be a boon for background solar wind models, which are essential for coronal mass ejection (CME) and shock propagation forecasting. From an operational perspective, the L5 orbit is the space weather equivalent to the geosynchronous orbit for weather satellites. Optimal for both research and monitoring, an L5 mission is ideal for developing a Research-to-Operations capability in Heliophysics.

  4. Near-Earth asteroid flyby trajectories from the Sun-Earth L2 for Chang'e-2's extended flight

    Science.gov (United States)

    Gao, Yang

    2013-02-01

    Driven by curiosity about possible flight options for the Chang'e-2 spacecraft after it remains at the Sun-Earth L2 point, effective approaches were developed for designing preliminary fuel-optimal near-Earth asteroid flyby trajectories. The approaches include the use of modified unstable manifolds, grid search of the manifolds' parameters, and a two-impulse maneuver for orbital phase matching and z-axis bias change, and are demonstrated to be effective in asteroid target screening and trajectory optimization. Asteroid flybys are expected to be within a distance of 2 × 107 km from the Earth owing to the constrained Earth-spacecraft communication range. In this case, the spacecraft's orbital motion is significantly affected by the gravities of both the Sun and the Earth, and therefore, the concept of the "heliocentric oscillating-Kepler orbit" is proposed, because the classical orbital elements of the flyby trajectories referenced in the heliocentric inertial frame oscillate significantly with respect to time. The analysis and results presented in this study show that, among the asteroids whose orbits are the most accurately predicted, "Toutatis", "2005 NZ6", or "2010 CL19" might be encountered by Chang'e-2 in late 2012 or 2013 with total impulses less than 100m/s.

  5. Near-Earth asteroid flyby trajectories from the Sun-Earth L2 for Chang'e-2's extended flight

    Institute of Scientific and Technical Information of China (English)

    Yang Gao

    2013-01-01

    Driven by curiosity about possible flight options for the Chang'e-2 spacecraft after it remains at the Sun-Earth L2 point,effective approaches were developed for designing preliminary fuel-optimal near-Earth asteroid flyby trajectories.The approaches include the use of modified unstable manifolds,grid search of the manifolds' parameters,and a two-impulse maneuver for orbital phase matching and z-axis bias change,and are demonstrated to be effective in asteroid target screening and trajectory optimization.Asteroid flybys are expected to be within a distance of 2 × 107 km from the Earth owing to the constrained Earth-spacecraft communication range.In this case,the spacecraft's orbital motion is significantly affected by the gravities of both the Sun and the Earth,and therefore,the concept of the“heliocentric oscillating-Kepler orbit” is proposed,because the classical orbital elements of the flyby trajectories referenced in the heliocentric inertial frame oscillate significantly with respect to time.The analysis and results presented in this study show that,among the asteroids whose orbits are the most accurately predicted,“Toutatis”,“2005 NZ6”,or “2010CL19” might be encountered by Chang'e-2 in late 2012 or 2013 with total impulses less than 100 m/s.

  6. 日地系统多物理耦合机制的设计与实现%Design and Implementation of Multi-physics Coupling Mechanism of Sun-Earth System

    Institute of Scientific and Technical Information of China (English)

    李姗姗; 王群

    2011-01-01

    以日地系统活动规律研究为背景,通过对SCIRUN提出的PRMI进行4点改进,提出一种高效的日地系统多物理耦合交互机制PRMI,能够在物理模型组件进行并行远程方法调用实现耦合交互的同时,自动实现网格重映射和数据并行分布重映射.实验结果证明PRMI具有较好的性能.%In the background of study on activity regularity of the sun-earth system, this paper proposes an efficient multi-physics coupling interaction mechanism PRMI++ for sun-earth system based on SCIRUN group's PRMI with four-point improvement. It can automatically accomplish gird re-mapping and parallel distribution re-mapping of data when the physical model components on the parallel remote method invocation to achieve coupling interactions. Experimental results prove PRMI++ has better performance.

  7. Research on Control Method of Keeping Flight Formation by Using SDRE on the Sun-Earth Libration Points

    Directory of Open Access Journals (Sweden)

    He Zhenqi

    2017-01-01

    Full Text Available Keeping the flying formation of spacecraft is a key problem which needs to be solved in deep space exploration missions. In this paper, the nonlinear dynamic model of formation flying is established and a series of transformations are carried out on this model equation. By using SDRE (State-Dependent Riccati Equation algorithm, the optimal control of flying formation is realized. Compared with the traditional control method based on the average orbit elements and LQR (Linear Quadratic Regulator control method, the SDRE control method has higher control precision and is more suitable for the advantages of continuous control in practical engineering. Finally, the parameter values of the sun-earth libration point L2 are substituted in the equation and simulation is performed. The simulation curves of SDRE controller are compared with LQR controller. The results show that the SDRE controllers time cost is less than the LQR controllers and the former’s fuel consumption is less than the latter’s in the system transition process.

  8. Controlling a transfer trajectory with realistic impulses assumming perturbations in the Sun-Earth-Moon Quasi-Bicircular Problem

    Science.gov (United States)

    Leiva, A. M.; Briozzo, C. B.

    In a previous work we successfully implemented a control algorithm to stabilize unstable periodic orbits in the Sun-Earth-Moon Quasi-Bicircular Problem (QBCP). Applying the same techniques, in this work we stabilize an unstable trajectory performing fast transfers between the Earth and the Moon in a dynamical system similar to the QBCP but incorporating the gravitational perturbation of the planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune, assumed to move on circular coplanar heliocentric orbits. In the control stage we used as a reference trajectory an unstable periodic orbit from the unperturbed QBCP. We performed 400 numerical experiments integrating the trajectories over time spans of ~40 years, taking for each one random values for the initial positions of the planets. In all cases the control impulses applied were larger than 20 cm/s, consistently with realistic implementations. The minimal and maximal yearly mean consumptions were ~10 m/s and ~71 m/s, respectively. FULL TEXT IN SPANISH

  9. Optimal design of near-Earth asteroid sample-return trajectories in the Sun-Earth-Moon system

    Science.gov (United States)

    He, Shengmao; Zhu, Zhengfan; Peng, Chao; Ma, Jian; Zhu, Xiaolong; Gao, Yang

    2016-08-01

    In the 6th edition of the Chinese Space Trajectory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-km-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engineering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selection, escape from and capture by the Earth-Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital resonance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid exploration.

  10. Optimal design of near-Earth asteroid sample-return trajectories in the Sun-Earth-Moon system

    Institute of Scientific and Technical Information of China (English)

    Shengmao He; Zhengfan Zhu; Chao Peng; Jian Ma; Xiaolong Zhu; Yang Gao

    2016-01-01

    In the 6th edition of the Chinese Space Trajec-tory Design Competition held in 2014, a near-Earth asteroid sample-return trajectory design problem was released, in which the motion of the spacecraft is modeled in multi-body dynamics, considering the gravitational forces of the Sun, Earth, and Moon. It is proposed that an electric-propulsion spacecraft initially parking in a circular 200-km-altitude low Earth orbit is expected to rendezvous with an asteroid and carry as much sample as possible back to the Earth in a 10-year time frame. The team from the Technology and Engi-neering Center for Space Utilization, Chinese Academy of Sciences has reported a solution with an asteroid sample mass of 328 tons, which is ranked first in the competition. In this article, we will present our design and optimization methods, primarily including overall analysis, target selec-tion, escape from and capture by the Earth–Moon system, and optimization of impulsive and low-thrust trajectories that are modeled in multi-body dynamics. The orbital res-onance concept and lunar gravity assists are considered key techniques employed for trajectory design. The reported solution, preliminarily revealing the feasibility of returning a hundreds-of-tons asteroid or asteroid sample, envisions future space missions relating to near-Earth asteroid explo-ration.

  11. Spacecraft Formation Flying near Sun-Earth L2 Lagrange Point: Trajectory Generation and Adaptive Full-State Feedback Control

    Science.gov (United States)

    Wong, Hong; Kapila, Vikram

    2004-01-01

    In this paper, we present a method for trajectory generation and adaptive full-state feedback control to facilitate spacecraft formation flying near the Sun-Earth L2 Lagrange point. Specifically, the dynamics of a spacecraft in the neighborhood of a Halo orbit reveals that there exist quasi-periodic orbits surrounding the Halo orbit. Thus, a spacecraft formation is created by placing a leader spacecraft on a desired Halo orbit and placing follower spacecraft on desired quasi-periodic orbits. To produce a formation maintenance controller, we first develop the nonlinear dynamics of a follower spacecraft relative to the leader spacecraft. We assume that the leader spacecraft is on a desired Halo orbit trajectory and the follower spacecraft is to track a desired quasi-periodic orbit surrounding the Halo orbit. Then, we design an adaptive, full-state feedback position tracking controller for the follower spacecraft providing an adaptive compensation for the unknown mass of the follower spacecraft. The proposed control law is simulated for the case of the leader and follower spacecraft pair and is shown to yield global, asymptotic convergence of the relative position tracking errors.

  12. Effectiveness of GeoWall Visualization Technology for Conceptualization of the Sun-Earth-Moon System

    Science.gov (United States)

    Turner, N. E.; Gray, C.; Mitchell, E. J.

    2004-12-01

    One persistent difficulty many introductory astronomy students face is the lack of a 3-dimensional mental model of the Earth-Moon system. Students without such a mental model can have a very hard time conceptualizing the geometric relationships that cause the cycle of lunar phases. The GeoWall is a recently developed and affordable projection mechanism for three-dimensional stereo visualization which is becoming a popular tool in classrooms and research labs. We present results from a study using a 3-D GeoWall with a simulated sunlit Earth-Moon system on undergraduate students' ability to understand the origins of lunar phases. We test students exposed to only in-class instruction, some with a laboratory exercise using the GeoWall Earth-Moon simulation, some students who were exposed to both, and some with an alternate activity involving lunar observations. Students are given pre and post tests using the a diagnostic test called the Lunar Phase Concept Inventory (LPCI). We discuss the effectiveness of this technology as a teaching tool for lunar phases.

  13. A small mission concept to the Sun-Earth Lagrangian L5 point for innovative solar, heliospheric and space weather science

    Science.gov (United States)

    Lavraud, B.; Liu, Y.; Segura, K.; He, J.; Qin, G.; Temmer, M.; Vial, J.-C.; Xiong, M.; Davies, J. A.; Rouillard, A. P.; Pinto, R.; Auchère, F.; Harrison, R. A.; Eyles, C.; Gan, W.; Lamy, P.; Xia, L.; Eastwood, J. P.; Kong, L.; Wang, J.; Wimmer-Schweingruber, R. F.; Zhang, S.; Zong, Q.; Soucek, J.; An, J.; Prech, L.; Zhang, A.; Rochus, P.; Bothmer, V.; Janvier, M.; Maksimovic, M.; Escoubet, C. P.; Kilpua, E. K. J.; Tappin, J.; Vainio, R.; Poedts, S.; Dunlop, M. W.; Savani, N.; Gopalswamy, N.; Bale, S. D.; Li, G.; Howard, T.; DeForest, C.; Webb, D.; Lugaz, N.; Fuselier, S. A.; Dalmasse, K.; Tallineau, J.; Vranken, D.; Fernández, J. G.

    2016-08-01

    We present a concept for a small mission to the Sun-Earth Lagrangian L5 point for innovative solar, heliospheric and space weather science. The proposed INvestigation of Solar-Terrestrial Activity aNd Transients (INSTANT) mission is designed to identify how solar coronal magnetic fields drive eruptions, mass transport and particle acceleration that impact the Earth and the heliosphere. INSTANT is the first mission designed to (1) obtain measurements of coronal magnetic fields from space and (2) determine coronal mass ejection (CME) kinematics with unparalleled accuracy. Thanks to innovative instrumentation at a vantage point that provides the most suitable perspective view of the Sun-Earth system, INSTANT would uniquely track the whole chain of fundamental processes driving space weather at Earth. We present the science requirements, payload and mission profile that fulfill ambitious science objectives within small mission programmatic boundary conditions.

  14. Restoration and Archiving of Data from the Plasma Composition Experiment on the International Sun-Earth Explorer One (ISEE 1)

    Science.gov (United States)

    Lennartsson, O. W.

    1997-01-01

    The objective of this project has been to complete the archiving of energetic (10 eV/epsilon - 18 keV/epsilon) ion composition data from the Lockheed Plasma Composition Experiment on the International Sun-Earth Explorer One (ISEE 1) satellite, using a particular data format that had previously been approved by NASA and the NSSDC. That same format, a combination of ion velocity moments and differential flux spectra, had been used in 1991 to archive, at the NSSDC, the first 28 months (the "Prime" period of ISEE investigations) of data from the Lockheed instrument under NASA Contract NAS5-33047. With the completion of this project, the almost 4 1/2-year time span of these unique data is now covered by a very compact set, approximately 1 gigabyte in total, of electronic files with physical quantities, all in ASCII. The files are organized by data type and time of data acquisition, in Universal Time, and named according to year and day of year. Each calendar day has five separate files (five types of data), the lengths of which vary from day to day, depending on the instrument mode of operation. The data format and file structure are described in detail in appendices 1 and 2. The physical medium consists of high-density (6250 cpi) 9-track magnetic tapes, complemented by a set of hardcopy line plots of certain plasma parameters. In this case there are five tapes, to be added to the six previous ones from 1991, and 25 booklets of plots, one per month, to be added to the previous 28. The tapes, including an extra standard-density (1600 cpi) tape with electronic versions of the Data User's Guide and self-guiding VAX/VMS command files, and the hardcopy plots are being boxed for shipment to the NSSDC.

  15. Restoration and Archiving of Data from the Plasma Composition Experiment on the International Sun-Earth Explorer One (ISEE 1)

    Science.gov (United States)

    Lennartsson, O. W.

    1997-08-01

    The objective of this project has been to complete the archiving of energetic (10 eV/epsilon - 18 keV/epsilon) ion composition data from the Lockheed Plasma Composition Experiment on the International Sun-Earth Explorer One (ISEE 1) satellite, using a particular data format that had previously been approved by NASA and the NSSDC. That same format, a combination of ion velocity moments and differential flux spectra, had been used in 1991 to archive, at the NSSDC, the first 28 months (the "Prime" period of ISEE investigations) of data from the Lockheed instrument under NASA Contract NAS5-33047. With the completion of this project, the almost 4 1/2-year time span of these unique data is now covered by a very compact set, approximately 1 gigabyte in total, of electronic files with physical quantities, all in ASCII. The files are organized by data type and time of data acquisition, in Universal Time, and named according to year and day of year. Each calendar day has five separate files (five types of data), the lengths of which vary from day to day, depending on the instrument mode of operation. The data format and file structure are described in detail in appendices 1 and 2. The physical medium consists of high-density (6250 cpi) 9-track magnetic tapes, complemented by a set of hardcopy line plots of certain plasma parameters. In this case there are five tapes, to be added to the six previous ones from 1991, and 25 booklets of plots, one per month, to be added to the previous 28. The tapes, including an extra standard-density (1600 cpi) tape with electronic versions of the Data User's Guide and self-guiding VAX/VMS command files, and the hardcopy plots are being boxed for shipment to the NSSDC.

  16. Sun, Earth and Sky

    Science.gov (United States)

    Lang, Kenneth R.

    1995-01-01

    The Sun is enveloped by a hot, tenuous million-degree corona that expands to create a continuous solar wind that sweeps past all the planets and fills the heliosphere. The solar wind is modulated by strong gusts that are initiated by powerful explosions on the Sun, including solar flares and coronal mass ejections. This dynamic, invisible outer atmosphere of the Sun is currently under observation with the soft X-ray telescope aboard the Yohkoh spacecraft, whose results are presented. We also show observations from the Ulysses spacecraft that is now passing over the solar pole, sampling the solar wind in this region for the first time. Two other spacecraft, Voyager 1 and 2, have recently detected the outer edge of the invisible heliosphere, roughly halfway to the nearest star. Magnetic solar activity, the total radiative output from the Sun, and the Earth's mean global surface temperature all vary with the 11-year sunspot cycle in which the total number of sunspots varies from a maximum to a minimum and back to a maximum again in about 11 years. The terrestrial magnetic field hollows out a protective magnetic cavity, called the magnetosphere, within the solar wind. This protection is incomplete, however, so the Sun feeds an unseen world of high-speed particles and magnetic fields that encircle the Earth in space. These particles endanger spacecraft and astronauts, and also produce terrestrial aurorae. An international flotilla of spacecraft is now sampling the weak points in this magnetic defense. Similar spacecraft have also discovered a new radiation belt, in addition to the familiar Van Allen belts, except fed by interstellar ions instead of electrons and protons from the Sun.

  17. 从日地系统L2出发借力月球飞越近地小行星%Near-Earth Asteroid Flyby Trajectories from the Sun-Earth L2 via Lunar Gravity Assist

    Institute of Scientific and Technical Information of China (English)

    何胜茂; 彭超; 高扬

    2016-01-01

    There are several flight options for the Chang’E-2 spacecraft after its remaining at the Sun-Earth L2 point, for example, impacting the Moon or recapture into lunar orbit, returning to Earth orbit or atmospheric reentry, heading for halo orbits of the Earth-Moon L1 or L2 or the Sun-Earth L1 point, as well as flying by near-Earth asteroids in interplanetary space (Finally, Chang’E-2 successfully implemented a close flyby of Toutatis, a potentially hazardous near-Earth asteroid, on Dec.13, 2012). The analyses of these flight options require designing preliminary transfer trajectories with total velocity impulses no more than 100 m/s in four-body dynamics, in which the motion of the spacecraft is influenced by the gravities of the Sun, Earth, and Moon. In this study, we shall present low-energy Toutatis flyby trajectories from a Sun-Earth L2 quasi-periodic orbit, specifically, via a single lunar gravity assist that is intentionally utilized for exploring potential benefits, compared with the direct transfer manner that is adopted in the practical mission. Compared with the direct transfer trajectories to the asteroid, lunar gravity assist is demonstrated to be capable of saving propellant for the Toutatis flyby mission, and the equivalent velocity impulses are 58.46 m/s.%对于停留在日地系统L2的“嫦娥2号”探测器,其后续飞行方案有多个选项,例如主动撞月或重返月球轨道、返回地球轨道或再入大气、飞往地月系统L1/L2或日地系统L1、进入深空飞越近地小行星(最终,“嫦娥2号”于2012年12月13日成功地实现了对Toutatis小行星的近距离飞越)。探讨上述的飞行方案需要对飞行轨道进行初步设计,总的速度脉冲限制在100 m/s以内并且需要考虑探测器同时受到太阳、地球、月球的引力作用。本研究设计了探测器从日地系统L2出发借力月球实现Toutatis小行星飞越的飞行方案,与直接飞越方案相比

  18. Connectivity in Autism: A review of MRI connectivity studies

    Science.gov (United States)

    Rane, Pallavi; Cochran, David; Hodge, Steven M.; Haselgrove, Christian; Kennedy, David; Frazier, Jean A.

    2016-01-01

    Autism Spectrum Disorder (ASD) affects 1 in 50 children between the ages of 6–17 years as per a 2012 CDC survey of parents. The etiology of ASD is not precisely known. ASD is an umbrella term, which includes low (IQ70) individuals. A better understanding of the disorder, and how it manifests in an individual subject can lead to more effective intervention plans to fulfill the individual’s treatment needs. Magnetic resonance imaging (MRI) is a non-invasive investigational tool that can help study the ways in which the brain develops and/or deviates from the typical developmental trajectory. MRI offers insights into the structure, function, and metabolism of the brain. In this article, we review published studies on brain connectivity changes in ASD using either resting state functional MRI or diffusion tensor imaging. The general findings of decreases in white matter integrity and long-range neural coherence are prevalent in ASD literature. However, there is somewhat less of a consensus in the detailed localization of these findings. There are even fewer studies linking these connectivity alterations with the behavioral phenotype of the disorder. Nevertheless, with the help of data sharing and large-scale analytic efforts, the field is advancing towards several convergent themes. These include reduced functional coherence of long-range intra-hemispheric cortico-cortical default mode circuitry, impaired inter-hemispheric regulation, and an associated, perhaps compensatory, increase in local and short-range cortico-subcortical coherence. PMID:26146755

  19. Preface to the Special Issue on "Connection of Solar and Heliospheric Activities with Near-Earth Space Weather: Sun-Earth Connection"

    Directory of Open Access Journals (Sweden)

    Chin-Chun Wu Sunny W. Y. Tam

    2013-01-01

    Full Text Available This special issue of the Terrestrial, Atmospheric and Oceanic Sciences (TAO presents a small collection of the materials presented at the 2011 International Space Plasma Symposium (ISPS, held at National Cheng-Kung University (NCKU in Tainan, Taiwan, Republic of China (ROC, from August 15 - 19, 2011. The purpose of the Symposium was to bring space physicists together to present their recent research results and discuss some outstanding questions in, but not limited to, the solar corona, interplanetary medium, planetary magnetosphere and ionospheres. A total number of 59 papers were presented at the Symposium by scientists from 11 countries and regions.

  20. Connecting Reading and Writing: A Case Study

    Science.gov (United States)

    Li, Zhanfang

    2015-01-01

    Connecting reading and writing, proposed by many scholars, is realized in this case study. The 30 participants in this study are the English majors of the third year in one School of Foreign Languages in Beijing. They are encouraged to write journals every week, based on the source text materials in their Intensive Reading class, with the final…

  1. The Sun-Earth connect 2: Modelling patterns of a fractal Sun in time and space using the fine structure constant

    Science.gov (United States)

    Baker, Robert G. V.

    2017-02-01

    Self-similar matrices of the fine structure constant of solar electromagnetic force and its inverse, multiplied by the Carrington synodic rotation, have been previously shown to account for at least 98% of the top one hundred significant frequencies and periodicities observed in the ACRIM composite irradiance satellite measurement and the terrestrial 10.7cm Penticton Adjusted Daily Flux data sets. This self-similarity allows for the development of a time-space differential equation (DE) where the solutions define a solar model for transmissions through the core, radiative, tachocline, convective and coronal zones with some encouraging empirical and theoretical results. The DE assumes a fundamental complex oscillation in the solar core and that time at the tachocline is smeared with real and imaginary constructs. The resulting solutions simulate for tachocline transmission, the solar cycle where time-line trajectories either 'loop' as Hermite polynomials for an active Sun or 'tail' as complementary error functions for a passive Sun. Further, a mechanism that allows for the stable energy transmission through the tachocline is explored and the model predicts the initial exponential coronal heating from nanoflare supercharging. The twisting of the field at the tachocline is then described as a quaternion within which neutrinos can oscillate. The resulting fractal bubbles are simulated as a Julia Set which can then aggregate from nanoflares into solar flares and prominences. Empirical examples demonstrate that time and space fractals are important constructs in understanding the behaviour of the Sun, from the impact on climate and biological histories on Earth, to the fractal influence on the spatial distributions of the solar system. The research suggests that there is a fractal clock underpinning solar frequencies in packages defined by the fine structure constant, where magnetic flipping and irradiance fluctuations at phase changes, have periodically impacted on the Earth and the rest of the solar system since time immemorial.

  2. Earth-Affecting Solar Causes Observatory (EASCO): A Potential International Living with a Star Mission from Sun-Earth L5

    Science.gov (United States)

    Gopalswamy, N.; Davila, J. M.; St Cyr, O. C.; Sittler, E. C.; Auchere, F.; Duvall, Jr. T. L.; Hoeksema, J. T.; Maksimovic, M.; MacDowall, R. J.; Szabo, A.; Collier, M. R.

    2011-01-01

    This paper describes the scientific rationale for an L5 mission and a partial list of key scientific instruments the mission should carry. The L5 vantage point provides an unprecedented view of the solar disturbances and their solar sources that can greatly advance the science behind space weather. A coronagraph and a heliospheric imager at L5 will be able to view CMEs broadsided, so space speed of the Earth-directed CMEs can be measured accurately and their radial structure discerned. In addition, an inner coronal imager and a magnetograph from L5 can give advance information on active regions and coronal holes that will soon rotate on to the solar disk. Radio remote sensing at low frequencies can provide information on shock-driving CMEs, the most dangerous of all CMEs. Coordinated helioseismic measurements from the Sun Earth line and L5 provide information on the physical conditions at the base of the convection zone, where solar magnetism originates. Finally, in situ measurements at L5 can provide information on the large-scale solar wind structures (corotating interaction regions (CIRs)) heading towards Earth that potentially result in adverse space weather.

  3. Examining Elementary School Students' Mental Models of Sun-Earth Relationships as a Result of Engaging in Engineering Design

    Science.gov (United States)

    Dankenbring, Chelsey; Capobianco, Brenda M.

    2016-01-01

    Current reform efforts in science education in the United States call for students to learn science through the integration of science and engineering practices. Studies have examined the effect of engineering design on students' understanding of engineering, technology, and science concepts. However, the majority of studies emphasize the accuracy…

  4. The effects of oblateness and solar radiation pressure on halo orbits in the photogravitational Sun-Earth system

    Science.gov (United States)

    Srivastava, Vineet K.; Kumar, Jai; Kushvah, Badam Singh

    2016-12-01

    In this paper, we construct a third-order analytic approximate solution using the Lindstedt-Poincare method in the photogravitational circular restricted three body problem considering the Sun as a radiating source and the Earth as an oblate spheroid for computing halo orbits around the collinear Lagrangian points L1 and L2. Further, the well-known differential correction and continuation schemes are used to compute halo orbits and their families numerically. The effects of solar radiation pressure and oblateness on the orbit are studied around both Lagrangian points. From the study, it is noticed that time period of the halo orbit increases around L1 and L2 accounting oblateness of the Earth and solar radiation pressure of the Sun. It is also found that stability of halo orbits is a weak function of the out-of-plane amplitude and mass reduction factor.

  5. On the Transfer and Control of Space Probes Around the L1 Point of the Sun-Earth+Moon System

    Science.gov (United States)

    Hou, Xi-Yun; Liu, Lin

    2008-01-01

    The motion around the collinear libration points in the restricted three body problem is unstable. But there exist conditionally stable periodic orbits around these points. Special-purpose space probes located in the vicinity of these points (e.g., ISEE-3, SOHO) can benefit from this dynamical property, in regard to maintaining the orbit in position and the energy required of placing the probe in position. As an example, we study in this paper the launch and orbital control of a space probe around the L1 libration point in the system consisting of the Sun and the Earth-Moon. We present some theoretical and numerical simulations' results, which may serve as a basis for the realization of such a space probe in future.

  6. Improving solar wind persistence forecasts: Removing transient space weather events, and using observations away from the Sun-Earth line

    Science.gov (United States)

    Kohutova, Petra; Bocquet, François-Xavier; Henley, Edmund M.; Owens, Matthew J.

    2016-10-01

    This study demonstrates two significant ways of improving persistence forecasts of the solar wind, which exploit the relatively unchanging nature of the ambient solar wind to provide 27 day forecasts, when using data from the Lagrangian L1 point. Such forecasts are useful as a prediction tool for the ambient wind, and for benchmarking of solar wind models. We show that solar wind persistence forecasts can be improved by removing transient solar wind features such as coronal mass ejections (CMEs). Using CME indicators to automatically identify CME-contaminated periods in ACE data from 1998 to 2011, and replacing these with solar wind from a previous synodic rotation, persistence forecasts improve (relative to a baseline): skill scores for Bz, a crucial parameter for determining solar wind geoeffectiveness, improve by 7.7 percentage points when using a proton temperature-based indicator with good operational potential. We also show that persistence forecasts can be improved by using measurements away from L1, to reduce the requirement on coronal stability for an entire synodic period, at the cost of reduced lead time. Using STEREO-B data from 2007 to 2013 to create such a reduced lead time persistence forecast, we show that Bz skill scores improve by 17.1 percentage points relative to ACE. Finally, we report on implications for persistence forecasts from any future missions to the L5 Lagrangian point and on the successful operational implementation (in spring 2015) of the normal (ACE-based) and reduced lead time (STEREO-based) persistence forecasts in the Met Office's Space Weather Operations Centre, as well as plans for future improvements.

  7. Impaired thalamocortical connectivity in autism spectrum disorder: a study of functional and anatomical connectivity.

    Science.gov (United States)

    Nair, Aarti; Treiber, Jeffrey M; Shukla, Dinesh K; Shih, Patricia; Müller, Ralph-Axel

    2013-06-01

    The thalamus plays crucial roles in the development and mature functioning of numerous sensorimotor, cognitive and attentional circuits. Currently limited evidence suggests that autism spectrum disorder may be associated with thalamic abnormalities, potentially related to sociocommunicative and other impairments in this disorder. We used functional connectivity magnetic resonance imaging and diffusion tensor imaging probabilistic tractography to study the functional and anatomical integrity of thalamo-cortical connectivity in children and adolescents with autism spectrum disorder and matched typically developing children. For connectivity with five cortical seeds (prefontal, parieto-occipital, motor, somatosensory and temporal), we found evidence of both anatomical and functional underconnectivity. The only exception was functional connectivity with the temporal lobe, which was increased in the autism spectrum disorders group, especially in the right hemisphere. However, this effect was robust only in partial correlation analyses (partialling out time series from other cortical seeds), whereas findings from total correlation analyses suggest that temporo-thalamic overconnectivity in the autism group was only relative to the underconnectivity found for other cortical seeds. We also found evidence of microstructural compromise within the thalamic motor parcel, associated with compromise in tracts between thalamus and motor cortex, suggesting that the thalamus may play a role in motor abnormalities reported in previous autism studies. More generally, a number of correlations of diffusion tensor imaging and functional connectivity magnetic resonance imaging measures with diagnostic and neuropsychological scores indicate involvement of abnormal thalamocortical connectivity in sociocommunicative and cognitive impairments in autism spectrum disorder.

  8. 日地平动点卫星两脉冲转移轨道设计%Two impulses transfer trajectory design for Sun-Earth libration point missions

    Institute of Scientific and Technical Information of China (English)

    李明涛; 郑建华; 于锡峥; 高东

    2009-01-01

    Two impulses transfer trajectory design based on the least differential corrections method was studied, differential correction equation with the altitude and the flight path angle constraints was concluded, and the convergence of the method was discussed. Halo orbit around the L_1 libration point of the Sun-Earth system was taken as the objective orbit, two impulses transfer trajectory was designed in the framework of the circular restricted three-body problem. Effect of Halo orbit insertion (HOI) point and amplitude was studied in a systematic way, a strategy for the selection of HOI point was given, and the fast transfer trajectory for e-mergency was also studied. Numerical simulation shows that the proposed method is very effective, and transfer trajectory with moderate flight time can be obtained by choosing points on the near Earth side of Halo orbit as HOI point.%研究基于最小二乘微分修正方法的平动点卫星两脉冲转移轨道设计,推导了考虑高度和航迹角约束的微分修正公式,讨论了该方法的收敛性.以日地L_1点附近的Halo轨道为目标轨道,在圆型限制性三体问题模型下设计了其转移轨道,系统地研究了HOI(Halo Orbit Insertion)点和Halo轨道幅值对转移轨道的影响,给出了HOI点的选择策略,并讨论了应急情况下快速转移轨道设计.数值仿真验证了方法的有效性,选择Halo轨道靠近地球侧的点作HOI点可以获得飞行时间适中的转移轨道.

  9. How do brain tumors alter functional connectivity? : A magnetoencephalography study

    NARCIS (Netherlands)

    Bartolomei, Fabrice; Bosma, Ingeborg; Klein, Martin; Baayen, Johannes C; Reijneveld, Jaap C; Postma, Tjeerd J; Heimans, Jan J; van Dijk, Bob W; de Munck, Jan C; de Jongh, Arent; Cover, Keith S; Stam, Cornelis J

    2006-01-01

    OBJECTIVE: This study was undertaken to test the hypothesis that brain tumors interfere with normal brain function by disrupting functional connectivity of brain networks. METHODS: Functional connectivity was assessed by computing the synchronization likelihood in a broad band (0.5-60Hz) or in the g

  10. Making the Reading, Writing, Social Studies Connection.

    Science.gov (United States)

    Jorgensen-Esmaili, Karen

    1990-01-01

    Suggests incorporating reading, writing, and social studies within the context of literature. Includes reading lists and activities for teaching about the Victorian period in a two-month social studies unit that incorporates science fiction, mysteries, and fairy tales. Children discuss old photographs, examine artifacts, visit a Victorian mansion,…

  11. Zika Connection to Rare Nerve Disorder Bolstered by Study

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_161325.html Zika Connection to Rare Nerve Disorder Bolstered by Study ... has developed the strongest evidence to date that Zika virus can cause a rare nerve disorder called ...

  12. Cold-formed steel pallet rack connection: an experimental study

    Science.gov (United States)

    Mohan, Vimal; Prabha, P.; Rajasankar, J.; Iyer, Nagesh R.; Raviswaran, N.; Nagendiran, V.; Kamalakannan, S. S.

    2015-03-01

    Industrial pallet rack systems are made up of three-dimensional structural arrangement using cold-formed steel members. The rack columns (upright) have perforations at prescribed intervals to facilitate the assemblage of beams with end connections. The tabs are used as connections which are engaged into the perforations and are in particular, highly semi-rigid in nature. Due to the diversity of rack systems, connecting member's stiffness and strength, it is almost impossible to develop a generalised model for analytical predication of the connection stiffness. This paper describes the beam-column connection tests carried out on a commercially available pallet rack system by adopting single cantilever test set-up. Thirty-five sets of combinations are identified based on the variation in upright profile and thickness, depth of beam and the connector to study the connection stiffness. Three tests were performed for each set to bring in uniformity in the result taking the total number of tests to 105. A full range parametric study is carried out to understand the influence of above said parameters on moment-rotation behaviour and the joint stiffness. The experimental results showed that an improved performance of the joint connection is achieved using connectors with more number of tabs, greater thickness and improved profile of the upright and larger depth of the beam.

  13. Field-based study of connectivity in an agricultural catchment

    Science.gov (United States)

    Lexartza-Artza, I.; Wainwright, J.

    2009-12-01

    Field-based studies of hydrological connectivity can provide context-specific knowledge that might both help understand dynamic complex systems and contribute to other synthetic or modelling approaches. The importance of such an understanding of catchment processes and also of the knowledge of catchment connections with water bodies and the changes of concentration with scale for Integrated Catchment Management has been increasingly emphasized. To provide a holistic understanding, approaches to the study of connectivity need to include both structural and functional aspects of the system and must consider the processes taking place within and across different temporal and spatial scales. A semi-quantitative nested approach has been used to investigate connectivity and study the interactions and feedbacks between the factors influencing transfer processes in the Ingbirchworth Catchment, in the uplands of the River Don, England. A series of reconnaissance techniques have been combined with monitoring of aspects such as rainfall, runoff, sediment transfer and soil-moisture distribution from plot to catchment scale and with consideration of linkages between land and water bodies. The temporal aspect has also been considered, with a special focus on the temporal distribution of events and the influence of longer term catchment changes such as those in land use and management practices. A variability of responses has been observed in relation to the characteristics of events, land use and scale of observation, with elements traditionally considered as limiting or enhancing connectivity responding differently under changing conditions. Sediment redistribution, reshaping of structure and consequent reinforcing loops can be observed across all land uses and landscape units, but the relevance it terms of effective connectivity of highly connected patches varies as the scale is increased. The knowledge acquired can contribute to recognise emerging processes significant for

  14. Brain network dynamics underlying visuospatial judgment: an FMRI connectivity study.

    Science.gov (United States)

    de Graaf, Tom A; Roebroeck, Alard; Goebel, Rainer; Sack, Alexander T

    2010-09-01

    Previous functional imaging research has consistently indicated involvement of bilateral fronto-parietal networks during the execution of visuospatial tasks. Studies with TMS have suggested that the right hemispheric network, but not the left, is functionally relevant for visuospatial judgments. However, very little is still known about the interactions within these fronto-parietal networks underlying visuospatial processing. In the current study, we investigated task modulation of functional connectivity (instantaneous correlations of regional time courses), and task-specific effective connectivity (direction of influences), within the right fronto-parietal network activated during visuospatial judgments. Ten healthy volunteers performed a behaviorally controlled visuospatial judgment task (ANGLE) or a control task (COLOR) in an fMRI experiment. Visuospatial task-specific activations were found in posterior parietal cortex (PPC) and middle/inferior frontal gyrus (MFG). Functional connectivity within this network was task-modulated, with significantly higher connectivity between PPC and MFG during ANGLE than during COLOR. Effective connectivity analysis for directed influence revealed that visuospatial task-specific projections within this network were predominantly in a frontal-to-parietal direction. Moreover, ANGLE-specific influences from thalamic nuclei to PPC were identified. Exploratory effective connectivity analysis revealed that closely neighboring clusters, within visuospatial regions, were differentially involved in the network. These neighboring clusters had opposite effective connectivity patterns to other nodes of the fronto-parietal network. Our data thus reveal that visuospatial judgments are supported by massive fronto-parietal backprojections, thalamo-parietal influence, and multiple stages, or loops, of information flow within the visuospatial network. We speculate on possible functional contributions of the various network nodes and

  15. Intercollegiate Collaboration: Connecting Social Studies Preservice Teachers at Two Universities

    Science.gov (United States)

    Hilburn, Jeremy; Maguth, Brad

    2012-01-01

    This qualitative case study explored the collaboration between students in two social studies methods courses at different universities. The authors used technology to connect preservice teachers from teacher education programs that differ in terms of geography, size, and type of university. Using archived data from the courses, the authors found…

  16. The development of the Heliometer of the Observatorio Nacional of Rio de Janeiro and application to the study of the Sun-Earth system

    CERN Document Server

    Neto, Eugênio Reis

    2013-01-01

    This work presents the development and construction of the Heliometer of the Observat\\'orio Nacional/MCTI. This instrument is designed to monitor changes on the solar diameter with the accuracy of the next-generation solar satellites. A review of the heliometric method is made and the building and testing of 4 prototypes is described. The instrument has a mirror objective split in dihedral, formed by the hemi-sections of a parabolic mirror. The materials that form the instrument have thermal and mechanical stability to 10^(-7). The number of optical parts is minimized and their quality is greater than {\\lambda}/12. An original software for the automated collection and analysis of the images was developed. With its latest version fully developed, we conducted an observational campaign of 9 days, deriving more than 70000 heliometric images of the Sun. The measured solar diameter has a standard deviation of 0.5 arcseconds, with no instrumental bias, and limited only by the provisional atmospheric modeling. There...

  17. COMPARATIVE ANATOMICAL STUDIES ABOUT CHICKEN SUB-BASAL CONNECTIONS

    Directory of Open Access Journals (Sweden)

    CARMEN BERGHES

    2013-07-01

    Full Text Available The studies aimed to describe the nervous formations from the base of the cranium in the hen and domestic duck. These clarifications are necessary in order to disclose some unknown facts regarding this region in the poultry species used preponderantly in laboratory studies of the aviary flu. The vegetative connections from the base of the skull have been studied on 10 poultry specimens, 5 hens and 5 ducks. The animals have been euthanatized using chloroform and a special dye has been injected through the heart in order to achieve a better differentiation of the nervous formations. Dissection was performed under a magnifying glass using instruments adequate to highly fine dissections. Photos and sketches of the dissected pieces have been taken. Nomina Anatomica (2003 was used to describe the observed formations.The studies showed that the cranial cervical ganglia around which is the sub-basal nervous tissue, is located on the border of the occipital hole, at the basis of the temporal pyramid, much deeper than in mammalians; it is better developed in the duck (3-4 mm than in the hen (1-2 mm; the cranial cervical ganglia has the shape of a globe in gallinaceans and it is long in shape in the ducks. A multitude of connecting branches were observed around the lymph node, linking it to the vague nerve, to the hypoglossal nerve, to the glossopharyngeal nerve and to the transversal paravertebral chain which is specific to poultry; an obvious branch detaches from the cranial pole, which is the sub-basal connective, while the cervical connective detaches from the caudal pole, connecting it to the cervical-thoracic lymph node.

  18. Personality goes a long a way: an interhemispheric connectivity study

    Directory of Open Access Journals (Sweden)

    Sylco S. Hoppenbrouwers

    2010-11-01

    Full Text Available Throughout the development of psychology the delineation of personality has played a central role. Together with the NEO-PI-R, a questionnaire derived from the Five Factor Model of Personality, and recent advances in research technology it is now possible to investigate the relationship between personality features and neurophysiological brain processes. The NEO-FFI, the short version of the NEO-PI-R, reliably measures five main personality traits: Neuroticism, Extraversion, Openness to experience, Agreeableness and Conscientiousness. As behaviour and some psychiatric disorders have been related to interhemispheric connectivity, the present study used the combination of transcranial magnetic stimulation (TMS and electroencephalography (EEG to measure frontal interhemispheric connectivity and its association with personality as indexed by the NEO-FFI. Results demonstrated that prefrontal interhemispheric connectivity between the left and right dorsolateral prefrontal cortex (DLPFC correlates with Agreeableness in healthy subjects. This is the first study to relate personality features to interhemispheric connectivity through TMS-EEG and suggests that Agreeableness relates to the effectiveness of prefrontal communication between hemispheres.

  19. Personality goes a long a way: an interhemispheric connectivity study.

    Science.gov (United States)

    Hoppenbrouwers, Sylco S; Farzan, Faranak; Barr, Mera S; Voineskos, Aristotle N; Schutter, Dennis J L G; Fitzgerald, Paul B; Daskalakis, Zafiris J

    2010-01-01

    Throughout the development of psychology the delineation of personality has played a central role. Together with the NEO-PI-R, a questionnaire derived from the Five Factor Model of Personality, and recent advances in research technology it is now possible to investigate the relationship between personality features and neurophysiological brain processes. The NEO-FFI, the short version of the NEO-PI-R, reliably measures five main personality traits: Neuroticism, Extraversion, Openness to experience, Agreeableness, and Conscientiousness. As behavior and some psychiatric disorders have been related to interhemispheric connectivity, the present study used the combination of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) to measure frontal interhemispheric connectivity and its association with personality as indexed by the NEO-FFI. Results demonstrated that prefrontal interhemispheric connectivity between the left and right dorsolateral prefrontal cortex correlates with Agreeableness in healthy subjects. This is the first study to relate personality features to interhemispheric connectivity through TMS-EEG and suggests that Agreeableness relates to the effectiveness of prefrontal communication between hemispheres.

  20. A study of subharmonics in connected speech material.

    Science.gov (United States)

    Kramer, Elena; Linder, Roland; Schönweiler, Rainer

    2013-01-01

    Subharmonics are often observed in running speech spectrograms that are difficult to quantify. This study investigates the relationship between rough voice quality and the presence-and amount-of subharmonics in connected speech material in a group of 35 male and 35 female speakers with voice pathology. Spectrum analysis was undertaken in 145 pathologic voices, of which 77 had subharmonics in connected speech. Only 34% of 70 subjects under investigation developed subharmonics in both connected speech and sustained phonations. All voices were judged as perceptually rough. The results of this study indicate that male and female voices with subharmonics do not differ in examined acoustic characteristics except for the modal fundamental frequency (F(0)). A small but significant difference in roughness scores between genders seems to be caused by the confounding perception of factors not related to acoustic measurements of F(0) and number of subharmonics. The degree of roughness has a significant relationship with the irregularity index, percentage of low F(0) estimates, and, to a lesser extent, power of subharmonics. Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  1. Connecting Refugees to Substance Use Treatment: A Qualitative Study.

    Science.gov (United States)

    McCleary, Jennifer S; Shannon, Patricia J; Cook, Tonya L

    2016-01-01

    An emerging body of literature identifies substance use as a growing concern among refugees resettling in the United States. Like immigrants, refugees may face cultural, linguistic, or systems barriers to connecting with mainstream substance use treatment programs, which may be compounded by refugees' unique experiences with exposure to trauma, displacement in refugee camps, and resettlement. This qualitative study explores factors that support and prevent refugees from connecting with chemical health treatment. Fifteen participants who identified as social service or public health professionals who work with refugees responded to an online, semistructured survey about their experiences referring refugees to substance use treatment. Resulting data was analyzed using thematic analysis. Themes emerged identifying a lack of culturally informed treatment models, policy issues, and client characteristics such as motivation and past trauma as barriers to engaging with treatment. Ongoing case management and coordination were identified as important to successful linkage. Findings from this study contribute to a better understanding of how to support refugees seeking substance use treatment and suggest that developing trauma informed, culturally relevant models of treatment that are integrated with primary health care and geographically accessible may enhance treatment linkage.

  2. Immunohistochemical study of subepidermal connective of molluscan integument

    Directory of Open Access Journals (Sweden)

    S Corbetta

    2010-01-01

    Full Text Available Sections of integument from gastropod, bivalve and cephalopod species were studied immunohistochemically to determine reactivity to antibody against the type I-like collagen from Sepia cartilage and antibodies against components of the extracellular matrix (ECM of vertebrate connective tissue: type I, III, IV, V, and VI collagens, laminin, nidogen and heparan sulphate. All samples exhibited similar reactivities to the antibodies, although differences in the intensity and localization of the immunostaining were found that were clearly correlated with between-species differences in integumental ultrastructure. These findings indicate that the composition of the integumental ECM is similar in the three classes of molluscs examined and that several types of collagen are present. However molluscan subepidermal connective tissue differs from the ECM of vertebrate dermis: molluscan integumental ECM contains collagens similar to type I, V and VI collagens but has no type III-similar collagen. Furthermore molecules similar to the type IV collagen, laminin, nidogen and heparan sulphate of vertebrates were present ubiquitously in molluscan basement membrane, confirming the statement that the structure and composition of basement membrane have remained constant throughout the evolution of all animal phyla.

  3. Neural connections foster social connections: a diffusion-weighted imaging study of social networks.

    Science.gov (United States)

    Hampton, William H; Unger, Ashley; Von Der Heide, Rebecca J; Olson, Ingrid R

    2016-05-01

    Although we know the transition from childhood to adulthood is marked by important social and neural development, little is known about how social network size might affect neurocognitive development or vice versa. Neuroimaging research has identified several brain regions, such as the amygdala, as key to this affiliative behavior. However, white matter connectivity among these regions, and its behavioral correlates, remain unclear. Here we tested two hypotheses: that an amygdalocentric structural white matter network governs social affiliative behavior and that this network changes during adolescence and young adulthood. We measured social network size behaviorally, and white matter microstructure using probabilistic diffusion tensor imaging in a sample of neurologically normal adolescents and young adults. Our results suggest amygdala white matter microstructure is key to understanding individual differences in social network size, with connectivity to other social brain regions such as the orbitofrontal cortex and anterior temporal lobe predicting much variation. In addition, participant age correlated with both network size and white matter variation in this network. These findings suggest the transition to adulthood may constitute a critical period for the optimization of structural brain networks underlying affiliative behavior.

  4. Always Connected: A Longitudinal Field Study of Mobile Communication

    NARCIS (Netherlands)

    Peters, O.; Ben Allouch, Soumaya

    2004-01-01

    Twenty-five novice users of a new mobile communication device, allowing them to be always connected to their e-mail, e-calendar and organizer via GPRS (General Packet Radio Service), were closely tracked for a period of three months. The benefits of being always connected, to be accessible at all ti

  5. Sensitivity Analysis of Initial Error for the Trajectory to the Sun-Earth Libration Point%飞往日-地动平衡点轨道初始误差敏感度分析

    Institute of Scientific and Technical Information of China (English)

    王亚敏; 乔栋; 崔平远

    2015-01-01

    对从环月轨道飞往日-地动平衡点轨道的转移轨道初始误差敏感度进行了数值仿真与分析。介绍了两种类型的转移轨道:长转移与短转移。建立初始速度误差与轨道末端偏差之间的数学关系式,采用数值计算获得了初始速度误差与轨道末端偏差量之间的线性关系曲线。通过建立轨道初始状态与末端状态量的一阶变分表达式,来说明始末偏差量呈线性关系的原因以及适用范围。研究表明,长转移轨道相较于短转移,对初始速度误差更为敏感,其始末偏差的线性关系适用范围更小。%The sensitivity of initial error for the transfer trajectory from lunar orbit to the Sun-Earth libration point orbit was calculated and analyzed.First,the short and long transfer trajectories for this kind of transfer issue were proposed.Then,the mathematical relation between initial error and terminal derivation was built.The relation is found to be linear by numerical calculation.Finally,the reason why the linear relation existed and its applicable conditions were explored by the first-order variation expression of initial error and terminal derivation.The result indicated that the long transfer is more sensitive to initial error than short transfer and that the applicable conditions for long transfer is stricter.

  6. CUNY Sun-Earth Research, Space Climate

    Science.gov (United States)

    Cotten, D. E.; Cheung, T. D.; Marchese, P. J.; Johnson, L. P.; Austin, S.; Tremberger, G.

    2007-05-01

    Faculty and students at Queensborough Community College and Medgar Evers College of the City University of New York (CUNY) have, over several years now, employed simple software familiar to most undergraduate students to perform useful calculations, including statistical analyses, regarding various geophysical phenomena. Topics have included Space Weather, Interplanetary Magnetic Field (IMF) direction and strength fluctuations, geomagnetic and ionospheric responses to solar flares, and Coronal Mass Ejection (CME) events. Our statistical analyses have utilized second-order measures of fluctuation of the IMF strength, especially what we now call the Cheung number: the number of times that the value of Sigma-B, as provided by the ACE (Advanced Composition Explorer) data, has exceeded 0.5nT during a 6 hour interval. We have also utilized the Higuchi fractal dimension of various somewhat random fluctuations, including Sigma-B and the brightness or strength of adjacent pixels or data points in somewhat random data sequences in time or spatial dimension, including IMF fluctuations and SOHO (Solar Heliographic Observer) images of the Sun. These we have correlated with each other and with such variables as SEP (Solar Energetic Particle) peak flux, TEC (Total Electron Content) of the ionosphere, and Dst (Disturbance storm-time) in the geomagnetic field. Recent results indicate that the IMF fluctuation measures are well correlated with the SEP peak flux, the Dst, and TEC. Higuchi fractal analysis of SOHO photospheric ultraviolet brightness indicates, consistent with concomitant increased chaos or randomness of photospheric brightness, an increased likelihood of solar flare events or CME affecting interplanetary space and the earth's magnetosphere/ionosphere/atmosphere.

  7. Alveolar ridge augmentation by connective tissue grafting using a pouch method and modified connective tissue technique: A prospective study

    Directory of Open Access Journals (Sweden)

    Ashish Agarwal

    2015-01-01

    Full Text Available Background: Localized alveolar ridge defect may create physiological and pathological problems. Developments in surgical techniques have made it simpler to change the configuration of a ridge to create a more aesthetic and more easily cleansable shape. The purpose of this study was to compare the efficacy of alveolar ridge augmentation using a subepithelial connective tissue graft in pouch and modified connective tissue graft technique. Materials and Methods: In this randomized, double blind, parallel and prospective study, 40 non-smoker individuals with 40 class III alveolar ridge defects in maxillary anterior were randomly divided in two groups. Group I received modified connective tissue graft, while group II were treated with subepithelial connective tissue graft in pouch technique. The defect size was measured in its horizontal and vertical dimension by utilizing a periodontal probe in a stone cast at base line, after 3 months, and 6 months post surgically. Analysis of variance and Bonferroni post-hoc test were used for statistical analysis. A two-tailed P < 0.05 was considered to be statistically significant. Results: Mean values in horizontal width after 6 months were 4.70 ± 0.87 mm, and 4.05 ± 0.89 mm for group I and II, respectively. Regarding vertical heights, obtained mean values were 4.75 ± 0.97 mm and 3.70 ± 0.92 mm for group I and group II, respectively. Conclusion: Within the limitations of this study, connective tissue graft proposed significantly more improvement as compare to connective tissue graft in pouch.

  8. Functional Connectivity Studies Of Patients With Auditory Verbal Hallucinations

    Directory of Open Access Journals (Sweden)

    Ralph E Hoffman

    2012-01-01

    Full Text Available Functional connectivity (FC studies of brain mechanisms leading to auditory verbal hallucinations (AVHs utilizing functional magnetic resonance imaging (fMRI data are reviewed. Initial FC studies utilized fMRI data collected during performance of various tasks, which suggested frontotemporal disconnection and/or source-monitoring.disturbances. Later FC studies have utilized resting (no-task fMRI data. These studies have produced a mixed picture of disconnection and hyperconnectivity involving different pathways associated with AVHs. Results of our most recent FC study of AVHs are reviewed in detail. This study suggests that the core mechanism producing AVHs involves not a single pathway, but a more complex functional loop. Components of this loop include Wernicke’s area and its right homologue, the left inferior frontal cortex, and the putamen. It is noteworthy that the putamen appears to play a critical role in the generation of spontaneous language, and in determining whether auditory stimuli are registered consciously as percepts. Excessive functional coordination linking this region with the Wernicke’s seed region in patients with schizophrenia could therefore generate an overabundance of potentially conscious language representations. In our model, intact FC in the other two legs of corticostriatal loop (Wernicke’s with left IFG, and left IFG with putamen appeared to allow this disturbance (common to schizophrenia overall to be expressed as a conscious hallucination of speech. Recommendations for future studies are discussed, including inclusion of multiple methodologies applied to the same subjects in order to compare and contrast different mechanistic hypotheses, utilizing EEG to better parse time-course of neural synchronization leading to AVHs, and ascertaining experiential subtypes of AVHs that may reflect distinct mechanisms.

  9. Can mouse imaging studies bring order to autism connectivity chaos?

    Directory of Open Access Journals (Sweden)

    Adam Liska

    2016-11-01

    Full Text Available Functional Magnetic Resonance Imaging (fMRI has consistently highlighted impaired or aberrant functional connectivity across brain regions of autism spectrum disorder (ASD patients. However, the manifestation and neural substrates of these alterations are highly heterogeneous and often conflicting. Moreover, their neurobiological underpinnings and etiopathological significance remain largely unknown. A deeper understanding of the complex pathophysiological cascade leading to aberrant connectivity in ASD can greatly benefit from the use of model organisms where individual pathophysiological or phenotypic components of ASD can be recreated and investigated via approaches that are either off limits or confounded by clinical heterogeneity. Despite some obvious limitations in reliably modelling the full phenotypic spectrum of a complex developmental disorder like ASD, mouse models have played a central role in advancing our basic mechanistic and molecular understanding of this syndrome. Recent progress in mouse brain connectivity mapping via resting-state fMRI (rsfMRI offers the opportunity to generate and test mechanistic hypotheses about the elusive origin and significance of connectional aberrations observed in autism. Here we discuss recent progress towards this goal, and illustrate initial examples of how the approach can be employed to establish causal links between ASD-related mutations, developmental processes, and brain connectional architecture. As the spectrum of genetic and pathophysiological components of ASD modelled in the mouse is rapidly expanding, the use of rsfMRI can advance our mechanistic understanding of the origin and significance of the connectional alterations associated with autism, and their heterogeneous expression across patient cohorts.

  10. Connecting Primary Health Care: A Comprehensive Pilot Study

    Directory of Open Access Journals (Sweden)

    Mehran Maghsoudloo

    2016-07-01

    Full Text Available The collection of data within the primary health care facilities in Iran is essentially paper-based. It is focused on family’s health, monitoring of non-infectious and infectious diseases. Clearly due to the paper-based nature of the tasks, timely decision making at most can be difficult if not impossible. As part of an on-going electronic health record implementation project at Tehran University of Medical Sciences, for the first time in the region, based on a comprehensive pilot project, four urban healthcare facilities are connected to their headquarters and beyond, covering all aspects of primary health care, for the last four years. Without delving into the technical aspects of its software engineering processes, the progress of the implementation is reported, selection of summarized data is presented, and experience gained thus far are discussed. Four years passed and if time is any important reason to go by, then it is safe to accept that the software architecture and electronic health record structural model implemented are robust and yet extensible. Aims and duration of a pilot study should be clearly defined prior to start and managed till its completion. Resistance to change and particularly to information technology, apart from its technical aspects, is also based on human factors.

  11. Gender differences in accessory connections location: an Israeli study.

    Science.gov (United States)

    Birati, Edo Y; Eldar, Michael; Belhassen, Bernard

    2012-09-01

    Recent studies have shown that the pathogenesis of accessory connections (AC) formation may have a genetic component. The purpose of the study was to examine whether AC location differs by gender in a large cohort of patients with AC undergoing radiofrequency ablation (RFA) in two Israeli electrophysiology (EP) laboratories. All consecutive patients who underwent RFA of single ACs in Tel Aviv Sourasky Medical Center between 1992 and 2009 (n = 574) as well as the first consecutive 230 patients who underwent RFA in Sheba Medical Center between 1992 and 2001 were included in this study. The 804 patients in the two centers included 511 males (63.6 %) and 293 (36.4 %) females, mean age 34 + 16 years old. The AC was located in the left free wall, posteroseptal, right free wall, right anteroseptal, and in other areas in 57.8, 22.8, 9.3, 7 and 3.1 % of patients, respectively. The anatomical AC distribution was similar in the two EP laboratories. A right free wall location was more frequent in females (13 %) than in males (7.2 %; p = 0.008). A right anteroseptal location was more frequent in males (8.4 %) than in females (4.4 %) (p = 0.043). The left free wall and posteroseptal locations were similarly encountered in males (58.1 and 23.1 %, respectively) and in females (57.3 and 22.2 %, respectively). In our Israeli population, females more commonly have right free wall ACs and males more commonly have right anteroseptal ACs. These findings support the possible role of a genetic component in the pathogenesis of AC formation.

  12. The Impact of Orthographic Connectivity on Visual Word Recognition in Arabic: A Cross-Sectional Study

    Science.gov (United States)

    Khateb, Asaid; Khateb-Abdelgani, Manal; Taha, Haitham Y.; Ibrahim, Raphiq

    2014-01-01

    This study aimed at assessing the effects of letters' connectivity in Arabic on visual word recognition. For this purpose, reaction times (RTs) and accuracy scores were collected from ninety-third, sixth and ninth grade native Arabic speakers during a lexical decision task, using fully connected (Cw), partially connected (PCw) and…

  13. Adapting Parcellation Schemes to Study Fetal Brain Connectivity in Serial Imaging Studies

    DEFF Research Database (Denmark)

    Cheng, Xi; Wilm, Jakob; Seshamani, Sharmishtaa

    2013-01-01

    of the developing fetal brain such functional and associated structural markers are not consistently present over time. In this study we adapt two non-atlas based parcellation schemes to study the development of connectivity networks of a fetal monkey brain using Diffusion Weighted Imaging techniques. Results......A crucial step in studying brain connectivity is the definition of the Regions Of Interest (ROI's) which are considered as nodes of a network graph. These ROI's identified in structural imaging reflect consistent functional regions in the anatomies being compared. However in serial studies...

  14. A Study of School District Superintendents and the Connection of Emotional Intelligence to Leadership

    Science.gov (United States)

    Hansen, Richard A.

    2009-01-01

    This study highlights the lack of studies that connect emotional intelligence to leadership. There are numerous studies of leadership and several studies about emotional intelligence; however, there are few studies that connect emotional intelligence to leadership. The study utilized the Bar-On Emotional Quotient Inventory (EQ-i) survey and the…

  15. Connecting Critical Theory of Technology to Educational Studies

    Science.gov (United States)

    Kruger-Ross, Matthew James

    2013-01-01

    In this article, I explore how transformative learning theory, an approach to educating drawn from adult education, can be used to provide access to the critical theory of technology for educators. Rather than focusing primarily on K-12 teachers and educational systems or higher education and other postsecondary instruction, I connect learning as…

  16. Connecting Critical Theory of Technology to Educational Studies

    Science.gov (United States)

    Kruger-Ross, Matthew James

    2013-01-01

    In this article, I explore how transformative learning theory, an approach to educating drawn from adult education, can be used to provide access to the critical theory of technology for educators. Rather than focusing primarily on K-12 teachers and educational systems or higher education and other postsecondary instruction, I connect learning as…

  17. Brain Connectivity Studies in Schizophrenia: Unravelling the Effects of Antipsychotics

    DEFF Research Database (Denmark)

    Nejad, A.B.; Ebdrup, Bjørn Hylsebeck; Glenthøj, Birte Yding;

    2012-01-01

    Impaired brain connectivity is a hallmark of schizophrenia brain dysfunction. However, the effect of drug treatment and challenges on the dysconnectivity of functional networks in schizophrenia is an understudied area. In this review, we provide an overview of functional magnetic resonance imaging...

  18. A Provisional Framework for Studying Information Connectivity in Food Networks

    OpenAIRE

    Engelseth, Per; Karlsen, Anniken

    2008-01-01

    Through a discussion of peculiarities of food supply, involving focus on information connectivity, a preliminary framework is sought that underlines joint responsibility in a complete supply chain of actors working in network context to achieve safe, quality and economic provision of products to end-use.

  19. A Histopathological Study of Pulmonary Hypertension in Connective Tissue Disease

    Directory of Open Access Journals (Sweden)

    Nobuhito Sasaki

    2011-01-01

    Full Text Available Connective tissue diseases (CTD, such as systemic sclerosis (SSc, systemic lupus erythematosus (SLE, and mixed connective tissue disease (MCTD, develop pulmonary hypertension (PH. Generally all PH cases associated with any CTD are classified into the same PH group. However, histological examination shows both common and specific lesions for each disease. In patients with SLE, fibrosis is generally rare and mild. The findings of PH in SLE are similar to those in primary pulmonary hypertension. Many cases of SSc are accompanied by fibrosis. MCTD is rather close to SSc. Arterial and arteriolar lesions of MCTD are characterized by fibrous intimal thickening. In this review, we describe the pathological features of PH associated with each CTD.

  20. Sex steroids and connectivity in the human brain: a review of neuroimaging studies.

    Science.gov (United States)

    Peper, Jiska S; van den Heuvel, Martijn P; Mandl, René C W; Hulshoff Pol, Hilleke E; van Honk, Jack

    2011-09-01

    Our brain operates by the way of interconnected networks. Connections between brain regions have been extensively studied at a functional and structural level, and impaired connectivity has been postulated as an important pathophysiological mechanism underlying several neuropsychiatric disorders. Yet the neurobiological mechanisms contributing to the development of functional and structural brain connections remain to be poorly understood. Interestingly, animal research has convincingly shown that sex steroid hormones (estrogens, progesterone and testosterone) are critically involved in myelination, forming the basis of white matter connectivity in the central nervous system. To get insights, we reviewed studies into the relation between sex steroid hormones, white matter and functional connectivity in the human brain, measured with neuroimaging. Results suggest that sex hormones organize structural connections, and activate the brain areas they connect. These processes could underlie a better integration of structural and functional communication between brain regions with age. Specifically, ovarian hormones (estradiol and progesterone) may enhance both cortico-cortical and subcortico-cortical functional connectivity, whereas androgens (testosterone) may decrease subcortico-cortical functional connectivity but increase functional connectivity between subcortical brain areas. Therefore, when examining healthy brain development and aging or when investigating possible biological mechanisms of 'brain connectivity' diseases, the contribution of sex steroids should not be ignored.

  1. Study on CAD/CAE System of Engine Connecting Rod

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The intensive competition of automotive market requ ir es shortening the product development circle and improving the product quality. Many of auto manufacturers in china have introduced some CAD/CAE/CAM systems in product development process, and have got some success. But the special and effi cient CAD system aimed at particular product is absent. This paper provides a CA D/CAE system that can realize the integration of CAD and CAE process for engine connecting rod development. The paper discusses som...

  2. On models for landscape connectivity:a case study of the new-born wetland of the Yellow River Delta

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The models for landscape connectivity are distinguished into models for line connectivity,vertex connectivity, network connectivity and patch connectivity separately. Because the models for line connectivity, for vertex connectivity, and for network connectivity have long been studied and have become ripe, the model for patch connectivity is paid special attention in this paper. The patch connectivity is defined as the average movement efficiency (minimizing movement distance) of animal migrants or plant propagules in patches of a region under consideration. According to this definition, a model for landscape connectivity is mathematically deduced to apply to GIS data. The application of model for patch connectivity in the new-bom wetland of the Yellow River Delta shows patch connectivity has a negative interrelation with human impact intensity and landscape diversity.

  3. Behavior of wet precast beam column connections under progressive collapse scenario: an experimental study

    Science.gov (United States)

    Nimse, Rohit B.; Joshi, Digesh D.; Patel, Paresh V.

    2014-12-01

    Progressive collapse denotes a failure of a major portion of a structure that has been initiated by failure of a relatively small part of the structure such as failure of any vertical load carrying element (typically columns). Failure of large part of any structure will results into substantial loss of human lives and natural resources. Therefore, it is important to prevent progressive collapse which is also known as disproportionate collapse. Nowadays, there is an increasing trend toward construction of buildings using precast concrete. In precast concrete construction, all the components of structures are produced in controlled environment and they are being transported to the site. At site such individual components are connected appropriately. Connections are the most critical elements of any precast structure, because in past major collapse of precast structure took place because of connection failure. In this study, behavior of three different 1/3rd scaled wet precast beam column connections under progressive collapse scenario are studied and its performance is compared with monolithic connection. Precast connections are constructed by adopting different connection detailing at the junction by considering reinforced concrete corbel for two specimens and steel billet for one specimen. Performance of specimen is evaluated on the basis of ultimate load carrying capacity, maximum deflection and deflection measured along the span of the beam. From the results, it is observed that load carrying capacity and ductility of precast connections considered in this study are more than that of monolithic connections.

  4. Quantifying hydrologic connectivity with measures from the brain neurosciences - a feasibility study

    Science.gov (United States)

    Rinderer, Michael; Ali, Genevieve; Larsen, Laurel

    2017-04-01

    While the concept of connectivity is increasingly applied in hydrology and ecology, little agreement exists on its definition and quantification approaches. In contrast, the neurosciences have developed a systematic conceptualization of connectivity and methods to quantify it. In particular, neuroscientists make a clear distinction between: 1) structural connectivity, which is determined by the anatomy of the brain neural network, 2) functional connectivity, that is based on statistical dependencies between neural signals, and 3) effective connectivity, that allows to infer causal relations based on the assumption that "true" interactions occur with a certain time delay. In a similar vein, in hydrology, structural connectivity can be defined as the physical adjacency of landscape elements that are seen as a prerequisite of material transfer, while functional or process connectivity would rather describe interactions or causal relations between spatial adjacency characteristics and temporally varying factors. While hydrologists have suggested methods to derive structural connectivity (SC), the quantification of functional (FC) or effective connectivity (EC) has remained elusive. The goal of the current study was therefore to apply timeseries analysis methods from brain neuroscience to quantify EC and FC among groundwater (n = 34) and stream discharge (n = 1) monitoring sites in a 20-ha Swiss catchment where topography is assumed to be a major driver of connectivity. SC was assessed through influence maps that quantify the percentage of flow from an upslope site to a downslope site by applying a multiple flow direction algorithm. FC was assessed by cross-correlation, total and partial mutual information while EC was quantified via total and partial entropy, Granger causality and a phase slope index. Our results showed that many structural connections were also expressed as functional or effective connections, which is reasonable in a catchment with shallow perched

  5. A Novel Pedicle Screw with Mobile Connection: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Yasuaki Tokuhashi

    2014-01-01

    Full Text Available To prevent adjacent disc problems after spinal fusion, a pedicle screw with a mobile junction between the head and threaded shaft was newly developed. The threaded shaft of the screw has 10 degrees mobility in all directions, but its structure is to prevent abnormal translation and tilting. This screw was evaluated as follows: (1 endurance test: 106 times rotational stress was applied; (2 biological reactions: novel screws with a mobile head and conventional screws with a fixed head were inserted into the bilateral pedicles of the L3, L4, and L5 in two mini pigs with combination. Eight months after surgery, vertebral units with the screw rod constructs were collected. After CT scan, the soft and bony tissues around the screws were examined grossly and histologically. As a result, none of the screws broke during the endurance test stressing. The mean amount of abrasion wear was 0.0338 g. In the resected mini pig section, though zygapophyseal joints between fixed-head screws showed bony union, the amount of callus in the zygapophyseal joints connected with mobile-head screws was small, and joint space was confirmed by CT. No metalloses were noted around any of the screws. Novel screws were suggested to be highly durable and histologically safe.

  6. Enhanced brain connectivity in math-gifted adolescents: An fMRI study using mental rotation.

    Science.gov (United States)

    Prescott, James; Gavrilescu, Maria; Cunnington, Ross; O'Boyle, Michael W; Egan, Gary F

    2010-12-01

    Mathematical giftedness is a form of intelligence related to enhanced mathematical reasoning that can be tested using a variety of numerical and spatial tasks. A number of neurobiological mechanisms related to exceptional mathematical reasoning ability have been postulated, including enhanced brain connectivity. We aimed to further investigate this possibility by comparing a group of mathematically gifted adolescents with an average math ability control group performing mental rotation of complex three-dimensional block figures. Functional magnetic resonance imaging (fMRI) data were collected and differences in intrahemispheric and interhemispheric connectivity between the groups were assessed using structural equation modeling (SEM). The math-gifted showed heightened intrahemispheric frontoparietal connectivity, as well as enhanced interhemispheric frontal connectivity between the dorsolateral prefrontal and premotor cortex. These enhanced connectivity patterns are consistent with previous studies linking increased activation of the frontal and parietal regions with high fluid intelligence, and may be a unique neural characteristic of the mathematically gifted brain.

  7. Default Mode Network Connectivity Encodes Clinical Pain: An Arterial Spin Labeling Study

    Science.gov (United States)

    Loggia, Marco L.; Kim, Jieun; Gollub, Randy L.; Vangel, Mark G.; Kirsch, Irving; Kong, Jian; Wasan, Ajay D.; Napadow, Vitaly

    2012-01-01

    Neuroimaging studies have suggested the presence of alterations in the anatomo-functional properties of the brain of patients with chronic pain. However, investigation of the brain circuitry supporting the perception of clinical pain presents significant challenges, particularly when using traditional neuroimaging approaches. While potential neuroimaging markers for clinical pain have included resting brain connectivity, these cross-sectional studies have not examined sensitivity to within-subject exacerbation of pain. We used the dual regression probabilistic Independent Component Analysis approach to investigate resting-state connectivity on Arterial Spin Labeling (ASL) data. Brain connectivity was compared between patients with chronic low back pain (cLBP) and healthy controls, before and after the performance of maneuvers aimed at exacerbating clinical pain levels in the patients. Our analyses identified multiple resting state networks, including the Default Mode Network (DMN). At baseline, patients demonstrated stronger DMN connectivity to the pregenual anterior cingulate cortex (pgACC), left inferior parietal lobule and right insula (rINS). Patients’ baseline clinical pain correlated positively with connectivity strength between the DMN and right insula (DMN-rINS). The performance of calibrated physical maneuvers induced changes in pain, which were paralleled by changes in DMN-rINS connectivity. Maneuvers also disrupted the DMN-pgACC connectivity, which at baseline was anti-correlated with pain. Finally, baseline DMN connectivity predicted maneuver-induced changes in both pain and DMN-rINS connectivity. Our results support the use of ASL to evaluate clinical pain, and the use of resting DMN connectivity as a potential neuroimaging biomarker for chronic pain perception. PMID:23111164

  8. On misunderstandings in connection with case-studies

    DEFF Research Database (Denmark)

    Flyvbjerg, Bent

    2005-01-01

    useful for generating hypotheses, while other methods aremore suitable for hypotheses testing and theory building; (4) The case study contains a bias toward verification; and (5) It is often difficult to summarize specific case studies. The article explains and corrects these misunderstandings one by one...

  9. Research, Practice, and Policy Connections: The Artplay Case Study

    Science.gov (United States)

    Brown, Robert; Jeanneret, Neryl

    2017-01-01

    This article explores the nexus between arts-based research, theory, practice, and policy. It does so through reference to a longitudinal study of ArtPlay, a unique Australian community arts center that offers artist-led workshops involving young people aged 3-13 years. The ethnographic and action research study investigated how children responded…

  10. A multivariate pattern analysis study of the HIV-related white matter anatomical structural connections alterations

    Science.gov (United States)

    Tang, Zhenchao; Liu, Zhenyu; Li, Ruili; Cui, Xinwei; Li, Hongjun; Dong, Enqing; Tian, Jie

    2017-03-01

    It's widely known that HIV infection would cause white matter integrity impairments. Nevertheless, it is still unclear that how the white matter anatomical structural connections are affected by HIV infection. In the current study, we employed a multivariate pattern analysis to explore the HIV-related white matter connections alterations. Forty antiretroviraltherapy- naïve HIV patients and thirty healthy controls were enrolled. Firstly, an Automatic Anatomical Label (AAL) atlas based white matter structural network, a 90 × 90 FA-weighted matrix, was constructed for each subject. Then, the white matter connections deprived from the structural network were entered into a lasso-logistic regression model to perform HIV-control group classification. Using leave one out cross validation, a classification accuracy (ACC) of 90% (P=0.002) and areas under the receiver operating characteristic curve (AUC) of 0.96 was obtained by the classification model. This result indicated that the white matter anatomical structural connections contributed greatly to HIV-control group classification, providing solid evidence that the white matter connections were affected by HIV infection. Specially, 11 white matter connections were selected in the classification model, mainly crossing the regions of frontal lobe, Cingulum, Hippocampus, and Thalamus, which were reported to be damaged in previous HIV studies. This might suggest that the white matter connections adjacent to the HIV-related impaired regions were prone to be damaged.

  11. Always connected: a longitudinal field study of mobile communication

    NARCIS (Netherlands)

    Peters, O.; Ben Allouch, Soumaya

    2005-01-01

    Twenty-five novice users of a new mobile communication device were closely tracked for a period of three months. The results of this longitudinal field study show that people’s motivations for using mobile communication technology are initially influenced more strongly by their perceptions about the

  12. Museum Studies: Connecting the Elementary and Secondary Experience

    Science.gov (United States)

    Martin, Kachina; Yoder, Maureen

    2009-01-01

    Museum studies will certainly reinforce students' appreciation of art history and art production. A student's understanding of a museum's function will deepen with each museum visit. Students will recognize that a museum can be organized around materials and kinds of art, periods of art history and cultures, and the works of an individual artist.…

  13. Oculomotor neurocircuitry, a structural connectivity study of infantile nystagmus syndrome.

    Directory of Open Access Journals (Sweden)

    Nasser H Kashou

    Full Text Available Infantile nystagmus syndrome (INS is one of the leading causes of significant vision loss in children and affects about 1 in 1000 to 6000 births. In the present study, we are the first to investigate the structural pathways of patients and controls using diffusion tensor imaging (DTI. Specifically, three female INS patients from the same family were scanned, two sisters and a mother. Six regions of interest (ROIs were created manually to analyze the number of tracks. Additionally, three ROI masks were analyzed using TBSS (Tract-Based Spatial Statistics. The number of fiber tracks was reduced in INS subjects, compared to normal subjects, by 15.9%, 13.9%, 9.2%, 18.6%, 5.3%, and 2.5% for the pons, cerebellum (right and left, brainstem, cerebrum, and thalamus. Furthermore, TBSS results indicated that the fractional anisotropy (FA values for the patients were lower in the superior ventral aspects of the pons of the brainstem than in those of the controls. We have identified some brain regions that may be actively involved in INS. These novel findings would be beneficial to the neuroimaging clinical and research community as they will give them new direction in further pursuing neurological studies related to oculomotor function and provide a rational approach to studying INS.

  14. How does Arabic orthographic connectivity modulate brain activity during visual word recognition: an ERP study.

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    Taha, Haitham; Ibrahim, Raphiq; Khateb, Asaid

    2013-04-01

    One of the unique features of the Arabic orthography that differentiates it from many other alphabetical ones is the fact that most letters connect obligatorily to each other. Hence, these letters change their forms according to the location in the word (i.e. beginning, middle, or end), leading to the suggestion that connectivity adds a visual load which negatively impacts reading in Arabic. In this study, we investigated the effects of the orthographic connectivity on the time course of early brain electric responses during the visual word recognition. For this purpose, we collected event-related potentials (ERPs) from adult skilled readers while performing a lexical decision task using fully connected (Cw), partially connected and non-connected words (NCw). Reaction times variance was higher and accuracy was lower in NCw compared to Cw words. ERPs analysis revealed significant amplitude and latency differences between Cw and NCw at posterior electrodes during the N170 component which implied the temporo-occipital areas. Our findings show that instead of slowing down reading, orthographic connectivity in Arabic skilled readers seems to impact positively the reading process already during the early stages of word recognition. These results are discussed in relation to previous observations in the literature.

  15. Brain connectivity study of brain tumor patients using MR-PET data: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Ana Carina [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon (Portugal); Ribeiro, Andre Santos [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon (Portugal); Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London (United Kingdom); Oros-Peusquens, Ana Maria; Langen, Karl Josef; Shah, Jon [Institute of Neuroscience and Medicine - 4, Forschungszentrum Juelich (Germany); Ferreira, Hugo Alexandre [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon (Portugal)

    2015-05-18

    Brain activity results from anatomical and functional connections that can be disrupted or altered due to trauma or lesion. This work presents a first approach on the study of whole-brain connectivity of brain tumor patients using the Multimodal Imaging Brain Connectivity (MIBCA) toolbox. Two patients with glioblastoma lesions located in the left hemisphere (one in the motor cortex and the other in the temporal lobe) underwent simultaneous MRI and dynamic PET scans using a 3T MRI scanner with a BrainPET insert. The following data was acquired: T1-w MPRAGE (1x1x1mm{sup 3}), DTI (dir=30, b=0,800s/mm2, 2x2x2mm{sup 3}), and dynamic 18F-FET PET. The MIBCA toolbox was used to automatically pre-process MRI-PET data and to derive imaging and connectivity metrics from the multimodal data. Computed metrics included: cortical thickness from T1-w data; mean diffusivity (MD), fractional anisotropy (FA), node degree, clustering coefficient and pairwise ROI fibre tracking (structural connectivity) from DTI data; and standardized uptake value (SUV) from PET data. For all the metrics, the differences between left and right hemispherical structures were obtained, followed by a 25% threshold (except for SUV thresholded at 15%). Data was visualized in a connectogram, and both structural connectivity and metrics were studied in regions surrounding lesions. Preliminary results showed increased SUV values in regions surrounding the tumor for both patients. Patients also showed changes in structural connectivity involving these regions and also other more spatially distant regions such as the putamen and the pallidum, including decreased number of fibers between the subcortical structures themselves and with frontal regions. These findings suggest that the presence of a tumor may alter both local and more distant structural connections. Presently, a larger patient sample is being studied along with the inclusion of a control group to test the consistency of the findings.

  16. Connective tissue spectrum abnormalities associated with spontaneous cerebrospinal fluid leaks: a prospective study.

    Science.gov (United States)

    Reinstein, Eyal; Pariani, Mitchel; Bannykh, Serguei; Rimoin, David L; Schievink, Wouter I

    2013-04-01

    We aimed to assess the frequency of connective tissue abnormalities among patients with cerebrospinal fluid (CSF) leaks in a prospective study using a large cohort of patients. We enrolled a consecutive group of 50 patients, referred for consultation because of CSF leak. All patients have been carefully examined for the presence of connective tissue abnormalities, and based on findings, patients underwent genetic testing. Ancillary diagnostic studies included echocardiography, eye exam, and histopathological examinations of skin and dura biopsies in selected patients. We identified nine patients with heritable connective tissue disorders, including Marfan syndrome, Ehlers-Danlos syndrome and other unclassified forms. In seven patients, spontaneous CSF leak was the first noted manifestation of the genetic disorder. We conclude that spontaneous CSF leaks are associated with a spectrum of connective tissue abnormalities and may be the first noted clinical presentation of the genetic disorder. We propose that there is a clinical basis for considering spontaneous CSF leak as a clinical manifestation of heritable connective tissue disorders, and we suggest that patients with CSF leaks should be screened for connective tissue and vascular abnormalities.

  17. Functional connectivity between the cerebrum and cerebellum in social cognition: A multi-study analysis.

    Science.gov (United States)

    Van Overwalle, Frank; Mariën, Peter

    2016-01-01

    This multi-study connectivity analysis explores the functional connectivity of the cerebellum with the cerebrum in social mentalizing, that is, understanding the mind of another person. The analysis covers 5 studies (n=92) involving abstract and complex forms of social mentalizing such as (a) person and group impression formation based on behavioral descriptions and (b) constructing personal counterfactual events (i.e., how the past could have turned out better). The results suggest that cerebellar activity during these social processes reflects a domain-specific mentalizing functionality that is strongly connected with a corresponding mentalizing network in the cerebrum. A significant pattern of connectivity was found linking the dorsal medial prefrontal cortex (mPFC) and the right temporo-parietal junction (TPJ) with the right posterior cerebellum, and linking the latter with the left TPJ. In addition, in the cerebrum, further connectivity was found through links of the bilateral TPJ with the dorsal mPFC, orbitofrontal cortex and between right and left TPJ. The discussion centers on the role of these cerebro-cerebellar connections in matching external information from the cerebrum with internal predictions generated by the cerebellum. These internal predictions might involve the sequencing of the person's behaviors. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Evaluation of phenoxybenzamine in the CFA model of pain following gene expression studies and connectivity mapping.

    Science.gov (United States)

    Chang, Meiping; Smith, Sarah; Thorpe, Andrew; Barratt, Michael J; Karim, Farzana

    2010-09-16

    We have previously used the rat 4 day Complete Freund's Adjuvant (CFA) model to screen compounds with potential to reduce osteoarthritic pain. The aim of this study was to identify genes altered in this model of osteoarthritic pain and use this information to infer analgesic potential of compounds based on their own gene expression profiles using the Connectivity Map approach. Using microarrays, we identified differentially expressed genes in L4 and L5 dorsal root ganglia (DRG) from rats that had received intraplantar CFA for 4 days compared to matched, untreated control animals. Analysis of these data indicated that the two groups were distinguishable by differences in genes important in immune responses, nerve growth and regeneration. This list of differentially expressed genes defined a "CFA signature". We used the Connectivity Map approach to identify pharmacologic agents in the Broad Institute Build02 database that had gene expression signatures that were inversely related ('negatively connected') with our CFA signature. To test the predictive nature of the Connectivity Map methodology, we tested phenoxybenzamine (an alpha adrenergic receptor antagonist) - one of the most negatively connected compounds identified in this database - for analgesic activity in the CFA model. Our results indicate that at 10 mg/kg, phenoxybenzamine demonstrated analgesia comparable to that of Naproxen in this model. Evaluation of phenoxybenzamine-induced analgesia in the current study lends support to the utility of the Connectivity Map approach for identifying compounds with analgesic properties in the CFA model.

  19. Mapping cortico-striatal connectivity onto the cortical surface: a new tractography-based approach to study Huntington disease.

    Directory of Open Access Journals (Sweden)

    Linda Marrakchi-Kacem

    Full Text Available Huntington disease (HD is associated with early and severe damage to the basal ganglia and particularly the striatum. We investigated cortico-striatal connectivity modifications occurring in HD patients using a novel approach which focuses on the projection of the connectivity profile of the basal ganglia onto the cortex. This approach consists in computing, for each subcortical structure, surface connectivity measures representing its strength of connections to the cortex and comparing these measures across groups. In this study, we focused on Huntington disease as an application of this new approach. First, surface cortico-striatal connectivity measures of a group of healthy subjects were averaged in order to infer the "normal" connectivity profile of the striatum to the cortex. Second, a statistical analysis was performed from the surface connectivity measures of healthy subjects and HD patients in order to detect the cortical gyri presenting altered cortico-striatal connectivity in HD. Lastly, percentage differences of connectivity between healthy subjects and patients were inferred, for each nucleus of the striatum, from the connectivity measures of the cortical gyri presenting a significant connectivity difference between the two groups. These percentage differences characterize the axonal disruptions between the striatum and the cortex occurring in HD. We found selective region-specific degeneration of cortical connections predominating for associative and primary sensorimotor connections and with relative preservation of limbic connections. Our method can be used to infer novel connectivity-based markers of HD pathological process.

  20. Connectivity of communication networks

    CERN Document Server

    Mao, Guoqiang

    2017-01-01

    This book introduces a number of recent developments on connectivity of communication networks, ranging from connectivity of large static networks and connectivity of highly dynamic networks to connectivity of small to medium sized networks. This book also introduces some applications of connectivity studies in network optimization, in network localization, and in estimating distances between nodes. The book starts with an overview of the fundamental concepts, models, tools, and methodologies used for connectivity studies. The rest of the chapters are divided into four parts: connectivity of large static networks, connectivity of highly dynamic networks, connectivity of small to medium sized networks, and applications of connectivity studies.

  1. Resting-state network disruption and APOE genotype in Alzheimer's disease: a lagged functional connectivity study.

    Directory of Open Access Journals (Sweden)

    Leonides Canuet

    Full Text Available BACKGROUND: The apolipoprotein E epsilon 4 (APOE-4 is associated with a genetic vulnerability to Alzheimer's disease (AD and with AD-related abnormalities in cortical rhythms. However, it is unclear whether APOE-4 is linked to a specific pattern of intrinsic functional disintegration of the brain after the development of the disease or during its different stages. This study aimed at identifying spatial patterns and effects of APOE genotype on resting-state oscillations and functional connectivity in patients with AD, using a physiological connectivity index called "lagged phase synchronization". METHODOLOGY/PRINCIPAL FINDINGS: Resting EEG was recorded during awake, eyes-closed state in 125 patients with AD and 60 elderly controls. Source current density and functional connectivity were determined using eLORETA. Patients with AD exhibited reduced parieto-occipital alpha oscillations compared with controls, and those carrying the APOE-4 allele had reduced alpha activity in the left inferior parietal and temporo-occipital cortex relative to noncarriers. There was a decreased alpha2 connectivity pattern in AD, involving the left temporal and bilateral parietal cortex. Several brain regions exhibited increased lagged phase synchronization in low frequencies, specifically in the theta band, across and within hemispheres, where temporal lobe connections were particularly compromised. Areas with abnormal theta connectivity correlated with cognitive scores. In patients with early AD, we found an APOE-4-related decrease in interhemispheric alpha connectivity in frontal and parieto-temporal regions. CONCLUSIONS/SIGNIFICANCE: In addition to regional cortical dysfunction, as indicated by abnormal alpha oscillations, there are patterns of functional network disruption affecting theta and alpha bands in AD that associate with the level of cognitive disturbance or with the APOE genotype. These functional patterns of nonlinear connectivity may potentially

  2. Altered resting-state functional connectivity in post-traumatic stress disorder: a perfusion MRI study

    Science.gov (United States)

    Li, Baojuan; Liu, Jian; Liu, Yang; Lu, Hong-Bing; Yin, Hong

    2013-03-01

    The majority of studies on posttraumatic stress disorder (PTSD) so far have focused on delineating patterns of activations during cognitive processes. Recently, more and more researches have started to investigate functional connectivity in PTSD subjects using BOLD-fMRI. Functional connectivity analysis has been demonstrated as a powerful approach to identify biomarkers of different brain diseases. This study aimed to detect resting-state functional connectivity abnormities in patients with PTSD using arterial spin labeling (ASL) fMRI. As a completely non-invasive technique, ASL allows quantitative estimates of cerebral blood flow (CBF). Compared with BOLD-fMRI, ASL fMRI has many advantages, including less low-frequency signal drifts, superior functional localization, etc. In the current study, ASL images were collected from 10 survivors in mining disaster with recent onset PTSD and 10 survivors without PTSD. Decreased regional CBF in the right middle temporal gyrus, lingual gyrus, and postcentral gyrus was detected in the PTSD patients. Seed-based resting-state functional connectivity analysis was performed using an area in the right middle temporal gyrus as region of interest. Compared with the non-PTSD group, the PTSD subjects demonstrated increased functional connectivity between the right middle temporal gyrus and the right superior temporal gyrus, the left middle temporal gyrus. Meanwhile, decreased functional connectivity between the right middle temporal gyrus and the right postcentral gyrus, the right superior parietal lobule was also found in the PTSD patients. This is the first study which investigated resting-state functional connectivity in PTSD using ASL images. The results may provide new insight into the neural substrates of PTSD.

  3. Connecting CO2. Feasibility study CO2 network Southwest Netherlands; Connecting CO2. Haalbaarheidsstudie CO2-netwerk Zuidwest-Nederland

    Energy Technology Data Exchange (ETDEWEB)

    Rutten, M.

    2009-06-10

    An overview is given of supply and demand of CO2 in the region Southwest Netherlands and the regions Antwerp and Gent in Belgium. Also attention is paid to possible connections between these regions [Dutch] Een inventarisatie wordt gegeven van vraag en aanbod van CO2 in de regio Zuidwest- Nederland en de regios Antwerpen en Gent in Belgie. Ook worden mogelijke koppelingen tussen de regios besproken.

  4. Decreased connectivity of the default mode network in pathological gambling: a resting state functional MRI study.

    Science.gov (United States)

    Jung, Myung Hun; Kim, Jae-Hun; Shin, Young-Chul; Jung, Wi Hoon; Jang, Joon Hwan; Choi, Jung-Seok; Kang, Do-Hyung; Yi, Jung-Seo; Choi, Chi-Hoon; Kwon, Jun Soo

    2014-11-01

    The default mode network (DMN) represents neuronal activity that is intrinsically generated during a resting state. The present study used resting-state fMRI to investigate whether functional connectivity is altered in pathological gambling (PG). Fifteen drug-naive male patients with PG and 15 age-matched male control subjects participated in the present study. The pathological gambling modification of the Yale-Brown Obsessive Compulsive Scale (PG-YBOCS), the Beck Depression Inventory, and the Beck Anxiety Inventory were used to determine symptom severity in all participants. Participants were instructed to keep their eyes closed and not to focus on any particular thoughts during the 4.68-min resting-state functional scan. The patients with PG displayed decreased default mode connectivity in the left superior frontal gyrus, right middle temporal gyrus, and precuneus compared with healthy controls. The severity of PG symptoms in patients with PG was negatively associated with connectivity between the posterior cingulate cortex seed region and the precuneus (r=-0.599, p=0.018). Decreased functional connectivity within DMN suggests that PG may share similar neurobiological abnormalities with other addictive disorders. Moreover, the severity of PG symptoms was correlated with decreased connectivity in the precuneus, which may be important in the response to treatment in patients with PG.

  5. The Relationship of Superficial Cutaneous Nerves and Interperforator Connections in the Leg: A Cadaveric Anatomical Study.

    Science.gov (United States)

    Gascoigne, Adam C; Ian Taylor, G; Corlett, Russell J; Briggs, Chris; Ashton, Mark W

    2017-04-01

    The lower limb is a source of many flaps both for closure of local defects and for free transfer. Fasciocutaneous flap techniques have been progressively refined, although the vascular basis for their success needs clarification. Archival studies of 48 lower limbs were reviewed and combined with 20 studies of lower limbs from fresh cadavers, making a total of 68 investigations. Lower limbs were injected with a dilute lead oxide solution; the integument was removed and radiographed; and the cutaneous nerves were dissected, tagged with wire, radiographed again, and their paths traced on the original images. The major cutaneous nerves in the leg are paralleled by a longitudinal vascular axis often comprising long branches with large-caliber true anastomotic connections between perforators. The most highly developed vascular axes followed the medial sural cutaneous and saphenous nerves, together with their accompanying veins, immediately superficial to the deep fascia. The intervening areas were characterized by shorter branches usually connected by small-caliber choke anastomotic connections. These findings provide the anatomical basis for the observed reliability of longitudinal flaps in the leg. The superficial cutaneous nerves of the leg, especially the saphenous and medial sural cutaneous nerves, are paralleled by a vascular axis on or beside the nerve comprising long perforator branches connected usually but not always by large-caliber true anastomotic connections. This emphasizes the importance of understanding the characteristics of interperforator anastomoses when designing and raising flaps.

  6. Connection, regulation, and care plan innovation: a case study of four nursing homes.

    Science.gov (United States)

    Colón-Emeric, Cathleen S; Lekan-Rutledge, Deborah; Utley-Smith, Queen; Ammarell, Natalie; Bailey, Donald; Piven, Mary L; Corazzini, Kirsten; Anderson, Ruth A

    2006-01-01

    We describe how connections among nursing home staff impact the care planning process using a complexity science framework. We completed six-month case studies of four nursing homes. Field observations (n = 274), shadowing encounters (n = 69), and in-depth interviews (n = 122) of 390 staff at all levels were conducted. Qualitative analysis produced a conceptual/thematic description and complexity science concepts were used to produce conceptual insights. We observed that greater levels of staff connection were associated with higher care plan specificity and innovation. Connection of the frontline nursing staff was crucial for (1) implementation of the formal care plan and (2) spontaneous informal care planning responsive to changing resident needs. Although regulations could theoretically improve cognitive diversity and information flow in care planning, we observed instances of regulatory oversight resulting in less specific care plans and abandonment of an effective care planning process. Interventions which improve staff connectedness may improve resident outcomes.

  7. Connection of Environmental Education with Application of Experiential Teaching Methods: A Case Study from Greece

    Science.gov (United States)

    Koutsoukos, Marios; Fragoulis, Iosif; Valkanos, Euthimios

    2015-01-01

    The main objective of this case study is to examine secondary education teachers' opinions concerning the connection of environmental education with the use of experiential teaching methods. Exploring whether the application of experiential methods can upgrade the learning procedure, leading to a more holistic approach, the research focuses on…

  8. Different cerebral connectivity of obese and lean children studied with fMRI

    Science.gov (United States)

    Anaya Moreno, Maryan A.; Hernández López, Javier M.; Hidalgo Tobón, Silvia; Dies Suarez, Pilar; Barragán Pérez, Eduardo; De Celis Alonso, Benito

    2014-11-01

    In this work we studied the different fMRI brain activations and connections between normal weighted (NW) and obese (OB) infants for different types of food odours. A total of 30 right handed volunteers (infants 8.4±2 years) of both sexes were studied. Infants were divided in two group, one with BMI between 19 and 24 kg/m2 and the other with BMI over 30 kg/m2. The first part of this project consisted of a study in which fMRI BOLD activations to pleasant, neutral and healthy food was performed on both groups. Cerebellum regions were found to be more active in the NW group over the OB when presented with odour cues. OB volunteers in contrast showed larger activations in cingulate cortex structures than their NW counterparts when presented with food odours. The second part of this study performed connectivity studies (ROI to ROI) comparing both groups for each smell. The NW group presented for the onion smell a strong reward anticipation connection between the gustatory cortex and the cingulate cortex which the OB group did not have. In contrast the OB group presented strong orbitofrontal connections (decision making) with gustatory and somatosensory cortex when stimulated with the chocolate odour which the NW did not present. We can conclude that clear differences in fMRI BOLD activation as well as connectivity between the OB and NW groups were found. This points at a very different processing mechanisms of odour cues in infants. To our knowledge this study has never been performed before on infants.

  9. Declining functional connectivity and changing hub locations in Alzheimer's disease: an EEG study.

    Science.gov (United States)

    Engels, Marjolein M A; Stam, Cornelis J; van der Flier, Wiesje M; Scheltens, Philip; de Waal, Hanneke; van Straaten, Elisabeth C W

    2015-08-20

    EEG studies have shown that patients with Alzheimer's disease (AD) have weaker functional connectivity than controls, especially in higher frequency bands. Furthermore, active regions seem more prone to AD pathology. How functional connectivity is affected in AD subgroups of disease severity and how network hubs (highly connected brain areas) change is not known. We compared AD patients with different disease severity and controls in terms of functional connections, hub strength and hub location. We studied routine 21-channel resting-state electroencephalography (EEG) of 318 AD patients (divided into tertiles based on disease severity: mild, moderate and severe AD) and 133 age-matched controls. Functional connectivity between EEG channels was estimated with the Phase Lag Index (PLI). From the PLI-based connectivity matrix, the minimum spanning tree (MST) was derived. For each node (EEG channel) in the MST, the betweenness centrality (BC) was computed, a measure to quantify the relative importance of a node within the network. Then we derived color-coded head plots based on BC values and calculated the center of mass (the exact middle had x and y values of 0). A shifting of the hub locations was defined as a shift of the center of mass on the y-axis across groups. Multivariate general linear models with PLI or BC values as dependent variables and the groups as continuous variables were used in the five conventional frequency bands. We found that functional connectivity decreases with increasing disease severity in the alpha band. All, except for posterior, regions showed increasing BC values with increasing disease severity. The center of mass shifted from posterior to more anterior regions with increasing disease severity in the higher frequency bands, indicating a loss of relative functional importance of the posterior brain regions. In conclusion, we observed decreasing functional connectivity in the posterior regions, together with a shifted hub location from

  10. About Connections

    Directory of Open Access Journals (Sweden)

    Kathleen S Rockland

    2015-05-01

    Full Text Available Despite the attention attracted by connectomics, one can lose sight of the very real questions concerning What are connections? In the neuroimaging community, structural connectivity is ground truth and underlying constraint on functional or effective connectivity. It is referenced to underlying anatomy; but, as increasingly remarked, there is a large gap between the wealth of human brain mapping and the relatively scant data on actual anatomical connectivity. Moreover, connections have typically been discussed as pairwise, point x projecting to point y (or: to points y and z, or more recently, in graph theoretical terms, as nodes or regions and the interconnecting edges. This is a convenient shorthand, but tends not to capture the richness and nuance of basic anatomical properties as identified in the classic tradition of tracer studies. The present short review accordingly revisits connectional weights, heterogeneity, reciprocity, topography, and hierarchical organization, drawing on concrete examples. The emphasis is on presynaptic long-distance connections, motivated by the intention to probe current assumptions and promote discussions about further progress and synthesis.

  11. Effect of MELT method on thoracolumbar connective tissue: The full study.

    Science.gov (United States)

    Sanjana, Faria; Chaudhry, Hans; Findley, Thomas

    2017-01-01

    Altered connective tissue structure has been identified in adults with chronic low back pain (LBP). A self-care treatment for managing LBP is the MELT method. The MELT method is a hands-off, self-treatment that is said to alleviate chronic pain, release tension and restore mobility, utilizing specialized soft treatments balls, soft body roller and techniques mimicking manual therapy. The objective of this study was to determine whether thickness of thoracolumbar connective tissue and biomechanical and viscoelastic properties of myofascial tissue in the low back region change in subjects with chronic LBP as a result of MELT. This study was designed using a quasi experimental pre-post- design that analyzed data from subjects who performed MELT. Using ultrasound imaging and an algorithm developed in MATLAB, thickness of thoracolumbar connective tissue was analyzed in 22 subjects. A hand-held digital palpation device, called the MyotonPRO, was used to assess biomechanical properties such as stiffness, elasticity, tone and mechanical stress relaxation time of the thoracolumbar myofascial tissue. A forward bending test assessing flexibility and pain scale was added to see if MELT affected subjects with chronic LBP. A significant decrease in connective tissue thickness and pain was observed in participants. Significant increase in flexibility was also recorded.

  12. Alternations of functional connectivity in amblyopia patients: a resting-state fMRI study

    Science.gov (United States)

    Wang, Jieqiong; Hu, Ling; Li, Wenjing; Xian, Junfang; Ai, Likun; He, Huiguang

    2014-03-01

    Amblyopia is a common yet hard-to-cure disease in children and results in poor or blurred vision. Some efforts such as voxel-based analysis, cortical thickness analysis have been tried to reveal the pathogenesis of amblyopia. However, few studies focused on alterations of the functional connectivity (FC) in amblyopia. In this study, we analyzed the abnormalities of amblyopia patients by both the seed-based FC with the left/right primary visual cortex and the network constructed throughout the whole brain. Experiments showed the following results: (1)As for the seed-based FC analysis, FC between superior occipital gyrus and the primary visual cortex was found to significantly decrease in both sides. The abnormalities were also found in lingual gyrus. The results may reflect functional deficits both in dorsal stream and ventral stream. (2)Two increased functional connectivities and 64 decreased functional connectivities were found in the whole brain network analysis. The decreased functional connectivities most concentrate in the temporal cortex. The results suggest that amblyopia may be caused by the deficits in the visual information transmission.

  13. Beta-Band Functional Connectivity Influences Audiovisual Integration in Older Age: An EEG Study

    Directory of Open Access Journals (Sweden)

    Luyao Wang

    2017-08-01

    Full Text Available Audiovisual integration occurs frequently and has been shown to exhibit age-related differences via behavior experiments or time-frequency analyses. In the present study, we examined whether functional connectivity influences audiovisual integration during normal aging. Visual, auditory, and audiovisual stimuli were randomly presented peripherally; during this time, participants were asked to respond immediately to the target stimulus. Electroencephalography recordings captured visual, auditory, and audiovisual processing in 12 old (60–78 years and 12 young (22–28 years male adults. For non-target stimuli, we focused on alpha (8–13 Hz, beta (13–30 Hz, and gamma (30–50 Hz bands. We applied the Phase Lag Index to study the dynamics of functional connectivity. Then, the network topology parameters, which included the clustering coefficient, path length, small-worldness global efficiency, local efficiency and degree, were calculated for each condition. For the target stimulus, a race model was used to analyze the response time. Then, a Pearson correlation was used to test the relationship between each network topology parameters and response time. The results showed that old adults activated stronger connections during audiovisual processing in the beta band. The relationship between network topology parameters and the performance of audiovisual integration was detected only in old adults. Thus, we concluded that old adults who have a higher load during audiovisual integration need more cognitive resources. Furthermore, increased beta band functional connectivity influences the performance of audiovisual integration during normal aging.

  14. The connective tissue of the adductor canal--a morphological study in fetal and adult specimens.

    Science.gov (United States)

    de Oliveira, Flavia; de Vasconcellos Fontes, Ricardo Bragança; da Silva Baptista, Josemberg; Mayer, William Paganini; de Campos Boldrini, Silvia; Liberti, Edson Aparecido

    2009-03-01

    The adductor canal is a conical or pyramid-shaped pathway that contains the femoral vessels, saphenous nerve and a varying amount of fibrous tissue. It is involved in adductor canal syndrome, a claudication syndrome involving young individuals. Our objective was to study modifications induced by aging on the connective tissue and to correlate them to the proposed pathophysiological mechanism. The bilateral adductor canals and femoral vessels of four adult and five fetal specimens were removed en bloc and analyzed. Sections 12 microm thick were obtained and the connective tissue studied with Sirius Red, Verhoeff, Weigert and Azo stains. Scanning electron microscopy (SEM) photomicrographs of the surfaces of each adductor canal were also analyzed. Findings were homogeneous inside each group. The connective tissue of the canal was continuous with the outer layer of the vessels in both groups. The pattern of concentric, thick collagen type I bundles in fetal specimens was replaced by a diffuse network of compact collagen bundles with several transversal fibers and an impressive content of collagen III fibers. Elastic fibers in adults were not concentrated in the thick bundles but dispersed in line with the transversal fiber system. A dynamic compression mechanism with or without an evident constricting fibrous band has been proposed previously for adductor canal syndrome, possibly involving the connective tissue inside the canal. The vessels may not slide freely during movement. These age-related modifications in normal individuals may represent necessary conditions for this syndrome to develop.

  15. Considering science and language arts connections: A study of teacher cognition

    Science.gov (United States)

    Baker, Linda; Saul, Wendy

    The Elementary Science Integration Project (ESIP) brought together teachers knowledgeable about, and committed to, whole-language instruction with their science-oriented counterparts to explore connections between the disciplines and build from teachers' strengths. By recognizing commonalities, that both hands-on science and whole language center on inquiry and focus on children's learning processes, ESIP was designed to reveal the issues both groups of teachers see as important as they go about making classroom decisions. The ultimate goal of the project was to promote science as central to cross-curricular study, thus increasing the comfort level of teachers, the amount of time devoted to science in the classroom, and an interest in inquiry. This article described the project and identified the considerations teachers used to evaluate science-language-arts connections. Twenty expert and 7 novice teachers worked together over a 2-year period to construct and elaborate their own understandings of curricular integrátion, designing action research projects to explore their newfound understandings. Teachers kept journals and participated in extensive group discussions and interviews that provided the data sources for this article. Results revealed the influence of teachers' scholarly and pedagogical orientations on the way they think about science-language-arts connections and the influence of personal experiences in convincing teachers that science-language-arts connections are worth fostering in the classroom.

  16. Peak Shaving Using Grid-Connected Solar Panels Case Study: Ministry of Islamic Affairs Mosque

    Directory of Open Access Journals (Sweden)

    Yousef B. Almutairi

    2014-08-01

    Full Text Available The main purpose of this paper is to introduce the application of renewable energy, namely solar energy,for peak shaving during peak loads and to investigate the feasibility of using grid-connected solar system for electricity generation in Ministry of Awqaf mosques. PVsyst software is used to find the optimal design for total connected load of 80 kW. The technical performance of 80 kWgrid-connected photovoltaic (PV solar systems was investigated. Applying renewable energy in building is required by Kuwait government, all sectors should use 30% of the consumed energy from renewable energy in year 2030. The total cost of the solar systems for 1400 mosques is around 512 million dollars and the total cost of energyis39 milliondollars per year according to 0.2 dollarwhich mean that the payback period within 13 years.Based on the study results, the development of grid-connected photovoltaic (PVsolar system in Awqaf mosques in Kuwait could be economically viable and provide peak shaving during peak loads.

  17. The Default Mode Network and Social Understanding of Others: What do Brain Connectivity Studies Tell Us

    Directory of Open Access Journals (Sweden)

    Wanqing eLi

    2014-02-01

    Full Text Available The Default Mode Network (DMN has been found to be involved in various domains of cognitive and social processing. The present article will review brain connectivity results related to the DMN in the fields of social understanding of others: emotion perception, empathy, theory of mind, and morality. Most of the reviewed studies focused on healthy subjects with no neurological and psychiatric disease, but some studies on patients with autism and psychopathy will also be discussed. Common results show that the medial prefrontal cortex (MPFC plays a key role in the social understanding of others, and the subregions of the MPFC contribute differently to this function according to their roles in different subsystems of the DMN. At the bottom, the ventral MPFC in the medial temporal lobe subsystem and its connections with emotion regions are mainly associated with emotion engagement during social interactions. Above, the anterior MPFC (aMPFC in the cortical midline structures and its connections with posterior and anterior cingulate cortex contribute mostly to making self-other distinctions. At the top, the dorsal MPFC (dMPFC in the dMPFC subsystem and its connection with the temporo-parietal junction (TPJ are primarily related to the understanding of other’s mental states. As behaviors become more complex, the related regions in frontal cortex are located higher. This reflects the transfer of information processing from automatic to cognitive processes with the increase of the complexity of social interaction. Besides the MPFC and TPJ, the connectivities of posterior cingulate cortex also show some changes during tasks from the four social fields. These results indicate that the DMN is indispensable in the social understanding of others.

  18. Synthesis Study on Transitions in Signal Infrastructure and Control Algorithms for Connected and Automated Transportation

    Energy Technology Data Exchange (ETDEWEB)

    Aziz, H. M. Abdul [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wang, Hong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Young, Stan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sperling, Joshua [National Renewable Energy Lab. (NREL), Golden, CO (United States); Beck, John [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-01

    Documenting existing state of practice is an initial step in developing future control infrastructure to be co-deployed for heterogeneous mix of connected and automated vehicles with human drivers while leveraging benefits to safety, congestion, and energy. With advances in information technology and extensive deployment of connected and automated vehicle technology anticipated over the coming decades, cities globally are making efforts to plan and prepare for these transitions. CAVs not only offer opportunities to improve transportation systems through enhanced safety and efficient operations of vehicles. There are also significant needs in terms of exploring how best to leverage vehicle-to-vehicle (V2V) technology, vehicle-to-infrastructure (V2I) technology and vehicle-to-everything (V2X) technology. Both Connected Vehicle (CV) and Connected and Automated Vehicle (CAV) paradigms feature bi-directional connectivity and share similar applications in terms of signal control algorithm and infrastructure implementation. The discussion in our synthesis study assumes the CAV/CV context where connectivity exists with or without automated vehicles. Our synthesis study explores the current state of signal control algorithms and infrastructure, reports the completed and newly proposed CV/CAV deployment studies regarding signal control schemes, reviews the deployment costs for CAV/AV signal infrastructure, and concludes with a discussion on the opportunities such as detector free signal control schemes and dynamic performance management for intersections, and challenges such as dependency on market adaptation and the need to build a fault-tolerant signal system deployment in a CAV/CV environment. The study will serve as an initial critical assessment of existing signal control infrastructure (devices, control instruments, and firmware) and control schemes (actuated, adaptive, and coordinated-green wave). Also, the report will help to identify the future needs for the signal

  19. Empirical Study of Traffic Velocity Distribution and its Effect on VANETs Connectivity

    CERN Document Server

    Abuelenin, Sherif M

    2015-01-01

    In this article we use real traffic data to confirm that vehicle velocities follow Gaussian distribution in steady state traffic regimes (free-flow, and congestion). We also show that in the transition between free-flow and congestion, the velocity distribution is better modeled by generalized extreme value distribution (GEV). We study the effect of the different models on estimating the probability distribution of connectivity duration between vehicles in vehicular ad-hoc networks.

  20. Nail changes in connective tissue diseases: a study of 39 cases

    OpenAIRE

    Elmansour, Imane; Chiheb, Soumia; Benchikhi, Hakima

    2014-01-01

    The objective is to identify nail unit changes associated with connective tissue diseases (CTD) and evaluate their frequency. We carried a prospective study between March 2012 and March2013 in our department. All patients with CTD were included. A clinical examination of the fingernails was done by the same dermatologist. Nail features were noted and classified and photos taken. Thirty nine patients were enrolled including: 16 systemic sclerosis, 14 lupus erythematosus (SLE), 8 dermatomyositi...

  1. A failure analysis study on the fractured connecting bolts of a filter press

    Directory of Open Access Journals (Sweden)

    Sh. Molaei

    2015-10-01

    Full Text Available The purpose of this study was to investigate the main causes of the co-fracture of sixteen connecting bolts of a filter press cylinder–piston system. Stress state of the bolts during the service conditions has been analyzed and the failure reasons were determined from the fractography analysis and gathered information. According to the obtained results, it was concluded that the bolts had failed by the fatigue mechanism. It seems that insufficient torque was used during assembly.

  2. A Study of Connectivity in MIMO Fadinc Ad-Hoc Networks

    Science.gov (United States)

    2008-08-04

    with a finite num- ber of mobile nodes. Some of the related articles in this area are [5], [20], [3], and [6]. Interestingly, connectiv - ity in random...of 1000 square meters according to a Poisson point process [13]. When measuring connectiv - ity, we assume all of the nodes can transmit at the same...thorough understanding of the connectiv - ity phenomenon. While this work has proposed analyt- ical measures for studying connectivity, we are

  3. Learn the effective connectivity pattern of attention networks: a resting functional MRI and Bayesian network study

    Science.gov (United States)

    Li, Juan; Li, Rui; Yao, Li; Wu, Xia

    2011-03-01

    Task-based neuroimaging studies revealed that different attention operations were carried out by the functional interaction and cooperation between two attention systems: the dorsal attention network (DAN) and the ventral attention network (VAN), which were respectively involved in the "top-down" endogenous attention orienting and the "bottomup" exogenous attention reorienting process. Recent focused resting functional MRI (fMRI) studies found the two attention systems were inherently organized in the human brain regardless of whether or not the attention process were required, but how the two attention systems interact with each other in the absence of task is yet to be investigated. In this study, we first separated the DAN and VAN by applying the group independent component analysis (ICA) to the resting fMRI data acquired from 12 healthy young subjects, then used Gaussian Bayesian network (BN) learning approach to explore the plausible effective connectivity pattern of the two attention systems. It was found regions from the same attention network were strongly intra-dependent, and all the connections were located in the information flow from VAN to DAN, which suggested that an orderly functional interactions and information exchanges between the two attention networks existed in the intrinsic spontaneous brain activity, and the inherent connections might benefit the efficient cognitive process between DAN and VAN, such as the "top-down" and "bottom-up" reciprocal interaction when attention-related tasks were involved.

  4. Abnormal brain connectivity patterns in adults with ADHD: a coherence study.

    Directory of Open Access Journals (Sweden)

    João Ricardo Sato

    Full Text Available Studies based on functional magnetic resonance imaging (fMRI during the resting state have shown decreased functional connectivity between the dorsal anterior cingulate cortex (dACC and regions of the Default Mode Network (DMN in adult patients with Attention-Deficit/Hyperactivity Disorder (ADHD relative to subjects with typical development (TD. Most studies used Pearson correlation coefficients among the BOLD signals from different brain regions to quantify functional connectivity. Since the Pearson correlation analysis only provides a limited description of functional connectivity, we investigated functional connectivity between the dACC and the posterior cingulate cortex (PCC in three groups (adult patients with ADHD, n=21; TD age-matched subjects, n=21; young TD subjects, n=21 using a more comprehensive analytical approach - unsupervised machine learning using a one-class support vector machine (OC-SVM that quantifies an abnormality index for each individual. The median abnormality index for patients with ADHD was greater than for TD age-matched subjects (p=0.014; the ADHD and young TD indices did not differ significantly (p=0.480; the median abnormality index of young TD was greater than that of TD age-matched subjects (p=0.016. Low frequencies below 0.05 Hz and around 0.20 Hz were the most relevant for discriminating between ADHD patients and TD age-matched controls and between the older and younger TD subjects. In addition, we validated our approach using the fMRI data of children publicly released by the ADHD-200 Competition, obtaining similar results. Our findings suggest that the abnormal coherence patterns observed in patients with ADHD in this study resemble the patterns observed in young typically developing subjects, which reinforces the hypothesis that ADHD is associated with brain maturation deficits.

  5. Hydrological connectivity of alluvial Andean valleys: a groundwater/surface-water interaction case study in Ecuador

    Science.gov (United States)

    Guzmán, Pablo; Anibas, Christian; Batelaan, Okke; Huysmans, Marijke; Wyseure, Guido

    2016-06-01

    The Andean region is characterized by important intramontane alluvial and glacial valleys; a typical example is the Tarqui alluvial plain, Ecuador. Such valley plains are densely populated and/or very attractive for urban and infrastructural development. Their aquifers offer opportunities for the required water resources. Groundwater/surface-water (GW-SW) interaction generally entails recharge to or discharge from the aquifer, dependent on the hydraulic connection between surface water and groundwater. Since GW-SW interaction in Andean catchments has hardly been addressed, the objectives of this study are to investigate GW-SW interaction in the Tarqui alluvial plain and to understand the role of the morphology of the alluvial valley in the hydrological response and in the hydrological connection between hillslopes and the aquifers in the valley floor. This study is based on extensive field measurements, groundwater-flow modelling and the application of temperature as a groundwater tracer. Results show that the morphological conditions of a valley influence GW-SW interaction. Gaining and losing river sections are observed in narrow and wide alluvial valley sections, respectively. Modelling shows a strong hydrological connectivity between the hillslopes and the alluvial valley; up to 92 % of recharge of the alluvial deposits originates from lateral flow from the hillslopes. The alluvial plain forms a buffer or transition zone for the river as it sustains a gradual flow from the hills to the river. Future land-use planning and development should include concepts discussed in this study, such as hydrological connectivity, in order to better evaluate impact assessments on water resources and aquatic ecosystems.

  6. Learning Connections

    Science.gov (United States)

    Royer, Regina D.; Richards, Patricia O.

    2005-01-01

    In this edition of Learning Connections, the authors show how technology can enhance study of weather patterns, reading comprehension, real-world training, critical thinking, health education, and art criticism. The following sections are included: (1) Social Studies; (2) Language Arts; (3) Computer Science and ICT; (4) Art; and (5) Health.…

  7. Study of data analysis methods in functional connectivity photoacoustic tomography (fcPAT)

    Science.gov (United States)

    Khodaee, Afsoon; Nasiriavanaki, Mohammadreza

    2017-03-01

    Resting-state functional connectivity (RSFC) is a method to monitor the health of the brain and find out abnormalities in brain networks. Recently functional connectivity photoacoustic tomography (fcPAT) has been used to study RSFC in the mouse brain. The current method of RSFC data analysis is called "seed-based". This method is not data-driven, and involves user intervention. Alternative signal processing approaches, such as singular value decomposition (SVD) and independent component analysis (ICA), will be explored to complement and cross validate the seed-based approach, possibly substituting them for the seed-based method. The methods are implemented and applied on the fcPAT data of a mouse brain.

  8. Study on interface behavior of 3D composites reinforced with chemically connected CNTs using molecular dynamics

    Science.gov (United States)

    Yang, Lin; He, Xiaodong; Tong, Liyong

    2009-07-01

    In this study, we used several molecular dynamic models to simulate the pull-out process of a carbon nanotube (CNT) that is assumed to be chemically connected to a carbon fiber, and to calculate the CNTs' geometry variation, displacement, energy and stress during this process. In the simulation, the CNTs' elongation and necking phenomena have been noted prior to the movement of the CNT's end embedded in resin. The simulation yields a CNT's plastic constitutive model in the pull-out process. The fracture resistance capability of a chemically connected CNT is then discussed. In the simulation of shearing, the prediction of the CNTs' capability of shear resistance has been conducted. Finally, by comparing the experiment result with the simulation, we predict the amido link break before the CNT pull-out in the shearing test.

  9. A comparative study of different transformer connections for railway power supply- mitigation of voltage unbalance

    DEFF Research Database (Denmark)

    Firat, Gurkan; Yang, Guangya; Ali Hussain Al-Ali, Haider

    2015-01-01

    The railway represents a large power consumer that can cause uneven loading of the phases in the high voltage grid. These unbalanced loads supplied by the utility may lead to voltage unbalance problems in the system and thereby affects the other consumers connected to the same network. It is fact...... that, voltage unbalance appears mainly as a result of unbalanced currents at the points of common coupling drawn by unevenly distributed loads. Because of a significant amount of negative sequence current injected to the system, the power system components will suffer from consequent negative effects...... such as overheating, additional losses of lines and transformers, interference with communication systems etc. This paper presents a comparative study of some transformer connections which commonly used in railway supplying AC traction loads, for voltage unbalance mitigations. Simulations for comparison...

  10. French concessive connectives and argumentation: an experimental study in eight- to ten-year-old children.

    Science.gov (United States)

    Champaud, C; Bassano, D

    1994-06-01

    An experimental study examined the comprehension of sentences containing concessive connectives, considered from an argumentative-conclusive point of view, in eight- and ten-year-old French children (24 subjects in each age group). Two tasks were used: subjects had to choose between (1) opposite preceding contexts of sentences (context choice task), and (2) conclusions that could be drawn from the same sentences (conclusion choice task). Results indicated a clear developmental increase in performance. For all concessive items, except mais ('but'), results of the context choice task were better than results of the conclusion choice task. Older children gave significantly better responses for mais in the conclusion choice task. The ambivalence of the connective mais is discussed; comparisons with production and crosslinguistic data are suggested.

  11. Top-down modulations from dorsal stream in lexical recognition: an effective connectivity FMRI study.

    Science.gov (United States)

    Deng, Yuan; Guo, Ruifang; Ding, Guosheng; Peng, Danling

    2012-01-01

    Both the ventral and dorsal visual streams in the human brain are known to be involved in reading. However, the interaction of these two pathways and their responses to different cognitive demands remains unclear. In this study, activation of neural pathways during Chinese character reading was acquired by using a functional magnetic resonance imaging (fMRI) technique. Visual-spatial analysis (mediated by the dorsal pathway) was disassociated from lexical recognition (mediated by the ventral pathway) via a spatial-based lexical decision task and effective connectivity analysis. Connectivity results revealed that, during spatial processing, the left superior parietal lobule (SPL) positively modulated the left fusiform gyrus (FG), while during lexical processing, the left SPL received positive modulatory input from the left inferior frontal gyrus (IFG) and sent negative modulatory output to the left FG. These findings suggest that the dorsal stream is highly involved in lexical recognition and acts as a top-down modulator for lexical processing.

  12. Connectivity of the amygdala, piriform, and orbitofrontal cortex during olfactory stimulation: a functional MRI study.

    Science.gov (United States)

    Nigri, Anna; Ferraro, Stefania; D'Incerti, Ludovico; Critchley, Hugo D; Bruzzone, Maria Grazia; Minati, Ludovico

    2013-03-06

    The majority of existing functional MRI studies on olfactory perception have addressed the relationship between stimulus features and the intensity of activity in separate regions considered in isolation. However, anatomical studies as well as neurophysiological recordings in rats and insects suggest that odor features may also be represented in a sparse manner through the simultaneous activity of multiple cortical areas interacting as a network. Here, we aimed to map the interdependence of neural activity among regions of the human brain, representing functional connectivity, during passive smelling. Seventeen healthy participants were scanned while performing a blocked-design task alternating exposure to two unpleasant odorants and breathing fresh air. High efferent connectivity was detected for the piriform cortex and the amygdala bilaterally. By contrast, the medial orbitofrontal cortex was characterized by high afferent connectivity, notably in the absence of an overall change in the intensity of hemodynamic activity during olfactory stimulation. Our results suggest that, even in the context of an elementary task, information on olfactory stimuli is scattered by the amygdala and piriform cortex onto an anatomically sparse representation and then gathered and integrated in the medial orbitofrontal cortex.

  13. MIP models for connected facility location: A theoretical and computational study.

    Science.gov (United States)

    Gollowitzer, Stefan; Ljubić, Ivana

    2011-02-01

    This article comprises the first theoretical and computational study on mixed integer programming (MIP) models for the connected facility location problem (ConFL). ConFL combines facility location and Steiner trees: given a set of customers, a set of potential facility locations and some inter-connection nodes, ConFL searches for the minimum-cost way of assigning each customer to exactly one open facility, and connecting the open facilities via a Steiner tree. The costs needed for building the Steiner tree, facility opening costs and the assignment costs need to be minimized. We model ConFL using seven compact and three mixed integer programming formulations of exponential size. We also show how to transform ConFL into the Steiner arborescence problem. A full hierarchy between the models is provided. For two exponential size models we develop a branch-and-cut algorithm. An extensive computational study is based on two benchmark sets of randomly generated instances with up to 1300 nodes and 115,000 edges. We empirically compare the presented models with respect to the quality of obtained bounds and the corresponding running time. We report optimal values for all but 16 instances for which the obtained gaps are below 0.6%.

  14. [Advances in the study on the role of connective tissue in the mechanical signal transduction of acupuncture].

    Science.gov (United States)

    Jiang, Xue-Mei; Zhang, Xue-Quan; Yuan, Lin

    2009-04-01

    Non-specific connective tissue (fascia connective tissue) plays an important role in the mechanical signal transduction of acupuncture. Acupuncture needle manipulation-induced mechanical stress has a certain effect on the fibroblasts and cytoskeleton in the nonspecific connective tissue (including loose connective tissue and fat tissue) in morphology, histochemistry and biochemistry. For example, acupuncture-needle manipulation can make the fibroblast deformed, the cytoskeleton remodeled and result in the release of biochemical materials from the connective tissue. The present review summarizes new results of studies on the effect of acupuncture needle manipulation from cytobiology, imageology and physiology; and holds that making clear the transduction pathways of acupuncture mechanical stress signals in the connective tissue and its impact on the organism possesses an important significance in revealing the mechanism of acupuncture underlying clinical therapeutic effects.

  15. Connecting speeds, directions and arrival times of 22 coronal mass ejections from the sun to 1 AU

    Energy Technology Data Exchange (ETDEWEB)

    Möstl, C.; Veronig, A. M.; Rollett, T.; Temmer, M.; Peinhart, V. [Kanzelhöhe Observatory-IGAM, Institute of Physics, University of Graz (Austria); Amla, K.; Hall, J. R.; Liewer, P. C.; De Jong, E. M. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA (United States); Colaninno, R. C. [Space Sciences Division, Naval Research Laboratory, Washington, DC (United States); Davies, J. A.; Harrison, R. A. [RAL Space, Harwell Oxford, Didcot (United Kingdom); Lugaz, N.; Farrugia, C. J.; Galvin, A. B. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH (United States); Liu, Y. D. [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing (China); Luhmann, J. G. [Space Science Laboratory, University of California, Berkeley, CA (United States); Vršnak, B., E-mail: christian.moestl@uni-graz.at [Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kačićeva 26, HR-10000, Zagreb (Croatia)

    2014-06-01

    Forecasting the in situ properties of coronal mass ejections (CMEs) from remote images is expected to strongly enhance predictions of space weather and is of general interest for studying the interaction of CMEs with planetary environments. We study the feasibility of using a single heliospheric imager (HI) instrument, imaging the solar wind density from the Sun to 1 AU, for connecting remote images to in situ observations of CMEs. We compare the predictions of speed and arrival time for 22 CMEs (in 2008-2012) to the corresponding interplanetary coronal mass ejection (ICME) parameters at in situ observatories (STEREO PLASTIC/IMPACT, Wind SWE/MFI). The list consists of front- and backsided, slow and fast CMEs (up to 2700 km s{sup –1}). We track the CMEs to 34.9 ± 7.1 deg elongation from the Sun with J maps constructed using the SATPLOT tool, resulting in prediction lead times of –26.4 ± 15.3 hr. The geometrical models we use assume different CME front shapes (fixed-Φ, harmonic mean, self-similar expansion) and constant CME speed and direction. We find no significant superiority in the predictive capability of any of the three methods. The absolute difference between predicted and observed ICME arrival times is 8.1 ± 6.3 hr (rms value of 10.9 hr). Speeds are consistent to within 284 ± 288 km s{sup –1}. Empirical corrections to the predictions enhance their performance for the arrival times to 6.1 ± 5.0 hr (rms value of 7.9 hr), and for the speeds to 53 ± 50 km s{sup –1}. These results are important for Solar Orbiter and a space weather mission positioned away from the Sun-Earth line.

  16. Experimental and analytical study of creep cracks damage in high temperature sodium plant branch connections

    Energy Technology Data Exchange (ETDEWEB)

    Corsi, F.; Fabi, A.; Di Giamberardino, P.; Botti, G.; Pasquale, G.; Dapor, V.

    1989-05-01

    A brief description of the operating conditions of the ESPRESSO sodium plant is given. The structural integrity problems of some ''T'' branch connections in the sodium plant are then presented. During a thermal cycling test a hydraulic packing loss is pointed out by a small amount of sodium leakage. Radiographic examinations revealed both a crack in the entire thickness and second partial crack in another branch connection. A series of technological tests was executed in which the presence of the cracks clearly indicated creep damage. To clarify the structural reliability of the most critical components a theoretical analysis of creep damage for the two branch connections was performed in detail. For this aim both elastic and inelastic analyses were carried out, with the general purpose CASTEM system developed at CEA Saclay, to determine the stress fields of the two components. The study tried to take into account the effects of the residual welding stresses in the creep regime. The main conclusions concerning the applications of the different existing rules are presented and compared. (orig./HP).

  17. Functional and structural brain connectivity of young binge drinkers: a follow-up study

    Science.gov (United States)

    Correas, A.; Cuesta, P.; López-Caneda, E.; Rodríguez Holguín, S.; García-Moreno, L. M.; Pineda-Pardo, J. A.; Cadaveira, F.; Maestú, F.

    2016-01-01

    Adolescence is a period of ongoing brain maturation characterized by hierarchical changes in the functional and structural networks. For this reason, the young brain is particularly vulnerable to the toxic effects of alcohol. Nowadays, binge drinking is a pattern of alcohol consumption increasingly prevalent among adolescents. The aim of the present study is to evaluate the evolution of the functional and anatomical connectivity of the Default Mode Network (DMN) in young binge drinkers along two years. Magnetoencephalography signal during eyes closed resting state as well as Diffusion Tensor Imaging (DTI) were acquired twice within a 2-year interval from 39 undergraduate students (22 controls, 17 binge drinkers) with neither personal nor family history of alcoholism. The group comparison showed that, after maintaining a binge drinking pattern along at least two years, binge drinkers displayed an increased brain connectivity of the DMN in comparison with the control group. On the other hand, the structural connectivity did not show significant differences neither between groups nor over the time. These findings point out that a continued pattern of binge drinking leads to functional alterations in the normal brain maturation process, even before anatomical changes can be detected. PMID:27506835

  18. Subdivision of the occipital lobes: an anatomical and functional MRI connectivity study.

    Science.gov (United States)

    Thiebaut de Schotten, Michel; Urbanski, Marika; Valabregue, Romain; Bayle, Dimitri J; Volle, Emmanuelle

    2014-07-01

    Exploring brain connectivity is fundamental to understanding the functional architecture of the cortex. In our study we employed tractography-based parcellation, combined with the principal component analysis statistical framework, to divide the occipital lobes into seven areas in a group of eighteen healthy participants. Tractography-based parcellation is a method based on diffusion imaging tractography, which segregates the living human brain into distinctive areas showing sharp differences in their anatomical connectivity. The results were compared to covarying functional networks involving distinct areas within the occipital lobes, that we obtained using resting state functional magnetic resonance imaging (fMRI), as well as to other existing subdivisions of the occipital lobes. Our results showed similarities with functional imaging data in healthy controls and cognitive profiles in brain-damaged patients, although several differences with cytoarchitectonic, myelogenetic, myeloarchitectonic and functional maps were reported. While the similarities are encouraging, the potential validity and limitations of the differences observed are discussed. Taken together these results suggest that tractography-based parcellation may provide a new promising anatomical subdivision of the living human brain based on its anatomical connectivity, which may benefit the understanding of clinical-neuroanatomical dissociations and functional neuroimaging results.

  19. The modulation of brain functional connectivity with manual acupuncture in healthy subjects: An electroencephalograph case study

    Science.gov (United States)

    Yi, Guo-Sheng; Wang, Jiang; Han, Chun-Xiao; Deng, Bin; Wei, Xi-Le; Li, Nuo

    2013-02-01

    Manual acupuncture is widely used for pain relief and stress control. Previous studies on acupuncture have shown its modulatory effects on the functional connectivity associated with one or a few preselected brain regions. To investigate how manual acupuncture modulates the organization of functional networks at a whole-brain level, we acupuncture at ST36 of a right leg to obtain electroencephalograph (EEG) signals. By coherence estimation, we determine the synchronizations between all pairwise combinations of EEG channels in three acupuncture states. The resulting synchronization matrices are converted into functional networks by applying a threshold, and the clustering coefficients and path lengths are computed as a function of threshold. The results show that acupuncture can increase functional connections and synchronizations between different brain areas. For a wide range of thresholds, the clustering coefficient during acupuncture and post-acupuncture period is higher than that during the pre-acupuncture control period, whereas the characteristic path length is shorter. We provide further support for the presence of “small-world" network characteristics in functional networks by using acupuncture. These preliminary results highlight the beneficial modulations of functional connectivity by manual acupuncture, which could contribute to the understanding of the effects of acupuncture on the entire brain, as well as the neurophysiological mechanisms underlying acupuncture. Moreover, the proposed method may be a useful approach to the further investigation of the complexity of patterns of interrelations between EEG channels.

  20. Incorporating landscape elements into a connectivity measure: a case study for the speckled wood butterfly (Pararge aegeria L.)

    NARCIS (Netherlands)

    Chardon, J.P.; Adriaensen, F.; Matthysen, E.

    2003-01-01

    In spatial studies of populations, Euclidean distance is commonly used to measure the structural connectivity between habitat patches. The role of the matrix on patch connectivity is thereby ignored. However, the importance of the matrix for (dispersal) movement is increasingly being acknowledged.

  1. An Analysis of Public Transit Connectivity Index in Tehran. The Case Study: Tehran Multi-Modal Transit Network

    Directory of Open Access Journals (Sweden)

    Amir Reza Mamdoohi

    2016-10-01

    Full Text Available Public transit is a major priority in modern management of large cities and metropolitan areas in particular. Public transit systems in such cities consist of a large number of nodes and lines which are represented by a complex network. A station for public transit is a bridge between the people and public transit network, based on which, the concept of input and output power for each station can be defined. The objective of this study is the application of the transit connectivity indices to the multimodal transit network in the city of Tehran. The public transit network data employed in this study is taken from Tehran Traffic Control Company, and Tehran Urban and Suburban Railway Operation Company. The methodology for measuring transit connectivity consists of three measures: Node connectivity, Line connectivity and Regional connectivity, where activity density is applied to these measures. The results of node connectivity analysis shows that most of the node connectivity in concentrated in the city center with many nodes in the center along routes going north and south. The line connectivity analysis shows that there is a concentration of highly connected lines that are near Tehran municipality region 12 and 16. Finally, we find that areas with more metro and bus facilities with respect to the other areas, have a better regional connectivity. One of these areas includes Sadeghiyeh Metro Station which is the junction of Tehran Metro Line 2 and Tehran Metro Line 5 which have a high connectivity power. Results of this study can be used to suggest some ideas on how future investments in rail and bus should be prioritized. Particularly in Transit Oriented Development (TOD and sustainble development projects, urban planners can design transit stations with high performance to access the crucial services in poor areas.

  2. Hydrodynamic modelling and global datasets: Flow connectivity and SRTM data, a Bangkok case study.

    Science.gov (United States)

    Trigg, M. A.; Bates, P. B.; Michaelides, K.

    2012-04-01

    The rise in the global interconnected manufacturing supply chains requires an understanding and consistent quantification of flood risk at a global scale. Flood risk is often better quantified (or at least more precisely defined) in regions where there has been an investment in comprehensive topographical data collection such as LiDAR coupled with detailed hydrodynamic modelling. Yet in regions where these data and modelling are unavailable, the implications of flooding and the knock on effects for global industries can be dramatic, as evidenced by the recent floods in Bangkok, Thailand. There is a growing momentum in terms of global modelling initiatives to address this lack of a consistent understanding of flood risk and they will rely heavily on the application of available global datasets relevant to hydrodynamic modelling, such as Shuttle Radar Topography Mission (SRTM) data and its derivatives. These global datasets bring opportunities to apply consistent methodologies on an automated basis in all regions, while the use of coarser scale datasets also brings many challenges such as sub-grid process representation and downscaled hydrology data from global climate models. There are significant opportunities for hydrological science in helping define new, realistic and physically based methodologies that can be applied globally as well as the possibility of gaining new insights into flood risk through analysis of the many large datasets that will be derived from this work. We use Bangkok as a case study to explore some of the issues related to using these available global datasets for hydrodynamic modelling, with particular focus on using SRTM data to represent topography. Research has shown that flow connectivity on the floodplain is an important component in the dynamics of flood flows on to and off the floodplain, and indeed within different areas of the floodplain. A lack of representation of flow connectivity, often due to data resolution limitations, means

  3. Coupling multielectrode array recordings with silver labeling of recording sites to study cervical spinal network connectivity.

    Science.gov (United States)

    Streeter, K A; Sunshine, M D; Patel, S R; Liddell, S S; Denholtz, L E; Reier, P J; Fuller, D D; Baekey, D M

    2017-03-01

    Midcervical spinal interneurons form a complex and diffuse network and may be involved in modulating phrenic motor output. The intent of the current work was to enable a better understanding of midcervical "network-level" connectivity by pairing the neurophysiological multielectrode array (MEA) data with histological verification of the recording locations. We first developed a method to deliver 100-nA currents to electroplate silver onto and subsequently deposit silver from electrode tips after obtaining midcervical (C3-C5) recordings using an MEA in anesthetized and ventilated adult rats. Spinal tissue was then fixed, harvested, and histologically processed to "develop" the deposited silver. Histological studies verified that the silver deposition method discretely labeled (50-μm resolution) spinal recording locations between laminae IV and X in cervical segments C3-C5. Using correlative techniques, we next tested the hypothesis that midcervical neuronal discharge patterns are temporally linked. Cross-correlation histograms produced few positive peaks (5.3%) in the range of 0-0.4 ms, but 21.4% of neuronal pairs had correlogram peaks with a lag of ≥0.6 ms. These results are consistent with synchronous discharge involving mono- and polysynaptic connections among midcervical neurons. We conclude that there is a high degree of synaptic connectivity in the midcervical spinal cord and that the silver-labeling method can reliably mark metal electrode recording sites and "map" interneuron populations, thereby providing a low-cost and effective tool for use in MEA experiments. We suggest that this method will be useful for further exploration of midcervical network connectivity.NEW & NOTEWORTHY We describe a method that reliably identifies the locations of multielectrode array (MEA) recording sites while preserving the surrounding tissue for immunohistochemistry. To our knowledge, this is the first cost-effective method to identify the anatomic locations of neuronal

  4. Brain connectivity study of joint attention using frequency-domain optical imaging technique

    Science.gov (United States)

    Chaudhary, Ujwal; Zhu, Banghe; Godavarty, Anuradha

    2010-02-01

    Autism is a socio-communication brain development disorder. It is marked by degeneration in the ability to respond to joint attention skill task, from as early as 12 to 18 months of age. This trait is used to distinguish autistic from nonautistic populations. In this study, diffuse optical imaging is being used to study brain connectivity for the first time in response to joint attention experience in normal adults. The prefrontal region of the brain was non-invasively imaged using a frequency-domain based optical imager. The imaging studies were performed on 11 normal right-handed adults and optical measurements were acquired in response to joint-attention based video clips. While the intensity-based optical data provides information about the hemodynamic response of the underlying neural process, the time-dependent phase-based optical data has the potential to explicate the directional information on the activation of the brain. Thus brain connectivity studies are performed by computing covariance/correlations between spatial units using this frequency-domain based optical measurements. The preliminary results indicate that the extent of synchrony and directional variation in the pattern of activation varies in the left and right frontal cortex. The results have significant implication for research in neural pathways associated with autism that can be mapped using diffuse optical imaging tools in the future.

  5. Connecting teens to caring adults in a school-based health center: a case study.

    Science.gov (United States)

    Blacksin, Beth A; Kelly, Patricia J

    2015-01-01

    The traditional medical care system is generally unable to provide the broad health and wellness services needed by many adolescents, especially those from low-income and racial/ethnic minority communities. Using a theoretical framework adapted from Bronfenbrenner's ecological model of multiple influencers, this case study examined how a school-based health center was able to provide a network of connections for adolescents to caring adults within the school and the local community. Contributors to this network were the creation of a student-centered community with access to adolescent-friendly services, providers acting as connectors, and care of the whole adolescent.

  6. Can spatial study of hydrological connectivity explain some behaviors of catchments?

    Science.gov (United States)

    Cantreul, Vincent

    2015-04-01

    Erosion is a major threat to European soil. Consequences can be very important both on-site and off-site. Belgian loamy soils are highly vulnerable to this threat because of their natural sensitivity to erosion on the one hand, and because the land is mainly used for intensive agricultural practices on the other hand. Over the last few decades, rising erosion has even been observed in our regions. This shows the importance of a deeper understanding of the coupled phenomena of runoff and erosion in order to manage soils at catchment scale. Plenty of research have already studied this but all agree to say that it seems to have a non-linear relationship between rainfall and discharge, as well as between rainfall and erosion. For that reason, a new concept has been developed a few years ago: the hydrological connectivity. Several research have focused on connectivity but up to now, each there are as much definition as papers. In this thesis, it will be important firstly to resume all these definitions to clarify this concept. Secondly, a methodology using various transects on the watershed and some pertinent field measurements will be used. These measurements include spatial distribution of particle size, surface states and soil moisture. A new approach of photogrammetry using an UAV will be used to observe erosion and deposition zones on the watershed. In this framework, several time scales will be studied from the event scale to the annual scale passing by monthly and seasonal scales. All this will serve to progress toward a better understanding of the concept of hydrological connectivity in order to study erosion at catchment scale. The final goal of this study is to describe hydrologically each different part of the catchment and to generalize these behaviors to other catchments with similar properties if possible. Afterwards, this research will be integrated in an existing (or not) model to improve the modelling of discharge and erosion in the catchment. Thanks to

  7. Studying the default mode and its mindfulness-induced changes using EEG functional connectivity

    OpenAIRE

    2013-01-01

    The default mode network (DMN) has been largely studied by imaging, but not yet by neurodynamics, using electroencephalography (EEG) functional connectivity (FC). mindfulness meditation (MM), a receptive, non-elaborative training is theorized to lower DMN activity. We explored: (i) the usefulness of EEG-FC for investigating the DMN and (ii) the MM-induced EEG-FC effects. To this end, three MM groups were compared with controls, employing EEG-FC (–MPC, mean phase coherence). Our results show t...

  8. Treatment-related changes in functional connectivity in brain tumor patients : a magnetoencephalography study

    NARCIS (Netherlands)

    Douw, Linda; Baayen, Hans; Bosma, Ingeborg; Klein, Martin; Vandertop, Peter; Heimans, Jan; Stam, Kees; de Munck, Jan; Reijneveld, Jaap

    2008-01-01

    Widespread disturbances in resting state functional connectivity between remote brain areas have been demonstrated in patients with brain tumors. Functional connectivity has been associated with neurocognitive deficits in these patients. Thus far, it is unknown how (surgical) treatment affects funct

  9. Trace elements have limited utility for studying migratory connectivity in shorebirds that winter in Argentina

    Science.gov (United States)

    Torres-Dowdall, J.; Farmer, A.H.; Abril, M.; Bucher, E.H.; Ridley, I.

    2010-01-01

    Trace-element analysis has been suggested as a tool for the study of migratory connectivity because (1) trace-element abundance varies spatially in the environment, (2) trace elements are assimilated into animals' tissues through the diet, and (3) current technology permits the analysis of multiple trace elements in a small tissue sample, allowing the simultaneous exploration of several elements. We explored the potential of trace elements (B, Na, Mg, Al, Si, P, S, K, Ca, Ti, Cr, Mn, Ni, Cu, Zn, As, Sr, Cs, Hg, Tl, Pb, Bi, Th, and U) to clarify the migratory connectivity of shorebirds that breed in North America and winter in southern South America. We collected 66 recently replaced secondary feathers from Red Knots (Calidris canutus) at three sites in Patagonia and 76 from White-rumped Sandpipers (C. fuscicollis) at nine sites across Argentina. There were significant differences in trace-element abundance in shorebird feathers grown at different nonbreeding sites, and annual variability within a site was small compared to variability among sites. Across Argentina, there was no large-scale gradient in trace elements. The lack of such a gradient restricts the application of this technique to questions concerning the origin of shorebirds to a small number of discrete sites. Furthermore, our results including three additional species, the Pectoral Sandpiper (C. melanotos), Wilson's Phalarope (Phalaropus tricolor), and Collared Plover (Charadrius collaris), suggest that trace-element profiles change as feathers age. Temporal instability of trace-element values could undermine their application to the study of migratory connectivity in shorebirds. ?? The Cooper Ornithological Society 2010.

  10. Age-related changes in functional connectivity of cerebellar PlV: a FDG PET study

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sang Soo; Yoon, Eun Jin; Bang, Seong Ae; Park, Hyun Soo; Kim, Yu Kyeong; Kim, Sang Eun [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2007-07-01

    The cerebellum is known to have strong connection with cerebral cortex, and it shows the greatest mean shrinkage with aging. Changes in functional connectivity between cerebellum and cortical and subcortical cerebral areas possibly occur in normal aging. In this study, we tested changes of interregional connection between cerebellar posterior inferior vermis (PIV) and cerebrum in healthy subjects divided in three classes of age group (young: 20-30, middle age: 40-50, elderly: over 60 years) using FDG PET. 211 healthy subjects (age, 20-82 y; 134 female) were studied with resting-state brain glucose utilization measured by FDG-PET, cerebellar PIV activity after count-normalization to the whole gray matter mean count was extracted. Using PIV count as a 'seed', the maps of cross-correlation coefficients were computed by measuring the correlation between 'seed' and all the other brain voxels (P < 0.001 uncorrected, k = 100). Across all age groups, positive correlations of metabolic activity in the cerebellar PIV showed in cerebellum itself and bilateral thalamus. An extended positive correlation in cuneus which is served for visual information processing was observed in middle aged and elderly group differently from the young group. Also, in elderly group, this correlation was observed in the frontal areas such as right orbital and precentral gyri. Negative correlation implicating mutual inhibition between the areas was also founded in prefrontal and cingulate cortices and temporoparietal association areas. Comparing with the young group, in theses areas, enlarged negative correlations was founded with aging. We identified age related changes in cerebrocerebellar communication loop which reflect changes in local neuroplasticity in the normal aging brain. Present result may have implication for understanding the functional decline of cerebellum related cognitive ability as well as the deficit of motor coordination in normal aging and its compensation

  11. Numerical and Experimental Study of the 3D Effect on Connecting Arm of Vertical Axis Tidal Current Turbine

    Institute of Scientific and Technical Information of China (English)

    郭伟; 康海贵; 陈兵; 谢宇; 王胤

    2016-01-01

    Vertical axis tidal current turbine is a promising device to extract energy from ocean current. One of the important components of the turbine is the connecting arm, which can bring about a significant effect on the pressure distribution along the span of the turbine blade, herein we call it 3D effect. However, so far the effect is rarely reported in the research, moreover, in numerical simulation. In the present study, a 3D numerical model of the turbine with the connecting arm was developed by using FLUENT software compiling the UDF (User Defined Function) command. The simulation results show that the pressure distribution along the span of blade with the connecting arm model is significantly different from those without the connecting arm. To facilitate the validation of numerical model, the laboratory experiment has been carried out by using three different types of NACA aerofoil connecting arm and circle section connecting arm. And results show that the turbine with NACA0012 connecting arm has the best start-up performance which is 0.346 m/s and the peak point of power conversion coefficient is around 0.33. A further study has been performed and a conclusion is drawn that the aerofoil and thickness of connecting arm are the most important factors on the power conversion coefficient of the vertical axis tidal current turbine.

  12. Considerations for Resting State Functional MRI and Functional Connectivity Studies in Rodents

    Directory of Open Access Journals (Sweden)

    Wen-Ju ePan

    2015-08-01

    Full Text Available Resting state functional MRI (rs-fMRI and functional connectivity mapping have become widely used tools in the human neuroimaging community and their use is rapidly spreading into the realm of rodent research as well. One of the many attractive features of rs-fMRI is that it is readily translatable from humans to animals and back again. Changes in functional connectivity observed in human studies can be followed by more invasive animal experiments to determine the neurophysiological basis for the alterations, while exploratory work in animal models can identify possible biomarkers for further investigation in human studies. These types of interwoven human and animal experiments have a potentially large impact on neuroscience and clinical practice. However, impediments exist to the optimal application of rs-fMRI in small animals, some similar to those encountered in humans and some quite different. In this review we identify the most prominent of these barriers, discuss differences between rs-fMRI in rodents and in humans, highlight best practices for animal studies, and review selected applications of rs-fMRI in rodents. Our goal is to facilitate the integration of human and animal work to the benefit of both fields.

  13. Modification of EEG power spectra and EEG connectivity in autobiographical memory: a sLORETA study.

    Science.gov (United States)

    Imperatori, Claudio; Brunetti, Riccardo; Farina, Benedetto; Speranza, Anna Maria; Losurdo, Anna; Testani, Elisa; Contardi, Anna; Della Marca, Giacomo

    2014-08-01

    The aim of the present study was to explore the modifications of scalp EEG power spectra and EEG connectivity during the autobiographical memory test (AM-T) and during the retrieval of an autobiographical event (the high school final examination, Task 2). Seventeen healthy volunteers were enrolled (9 women and 8 men, mean age 23.4 ± 2.8 years, range 19-30). EEG was recorded at baseline and while performing the autobiographical memory (AM) tasks, by means of 19 surface electrodes and a nasopharyngeal electrode. EEG analysis was conducted by means of the standardized LOw Resolution Electric Tomography (sLORETA) software. Power spectra and lagged EEG coherence were compared between EEG acquired during the memory tasks and baseline recording. The frequency bands considered were as follows: delta (0.5-4 Hz); theta (4.5-7.5 Hz); alpha (8-12.5 Hz); beta1 (13-17.5 Hz); beta2 (18-30 Hz); gamma (30.5-60 Hz). During AM-T, we observed a significant delta power increase in left frontal and midline cortices (T = 3.554; p < 0.05) and increased EEG connectivity in delta band in prefrontal, temporal, parietal, and occipital areas, and for gamma bands in the left temporo-parietal regions (T = 4.154; p < 0.05). In Task 2, we measured an increased power in the gamma band located in the left posterior midline areas (T = 3.960; p < 0.05) and a significant increase in delta band connectivity in the prefrontal, temporal, parietal, and occipital areas, and in the gamma band involving right temporo-parietal areas (T = 4.579; p < 0.05). These results indicate that AM retrieval engages in a complex network which is mediated by both low- (delta) and high-frequency (gamma) EEG bands.

  14. Our Solar Connection: A Themed Set of Activities for Grades 5-12

    Science.gov (United States)

    Gary, D. E.; van der Veen, W.; Gallagher, A.

    2005-05-01

    We present a set of 7 interconnected activities on the theme of Sun-Earth connections that we have developed and presented at teacher workshops as part of a NASA-funded Education and Public Outreach project. Associated with the activities are two resource centers that are maintained locally at NJIT in Newark, NJ, and at Raritan Valley Community College (RVCC) in North Branch, NJ. We describe each of the activities and the resource equipment, and present some statistics of how successful the teachers have been in using the activities in their classrooms. A resource CD containing the text of a teacher's guide is available that explains each activity, lists the associated materials needed for each activity, gives estimates for the time required for each activity, and points out specific New Jersey Science Standards met by each activity. Additional resources including movies and photos are included on the CD, and links to this material are contained in the teacher's guide.

  15. The Impact of work-life connectivity on professional women: A case study of telecom industry

    Directory of Open Access Journals (Sweden)

    Zahida Latif

    2016-06-01

    Full Text Available The purpose of this research was to test work life border theory against job/life satisfaction. The impact of work-life connectivity on professional women working in telecom industry was checked. This quantitative research was conducted by collecting secondary data gathered through world recognized questionnaires. A sample size of 285 respondents was collected through Qualtrics and self-administered questionnaires. This sample was adequate as using Power and Precision software a minimum sample of 175 was computed. Cluster sampling technique in combination with stratified sampling was used to collect data from women in Telecom Industry from major cities of Pakistan. Data collected was analyzed in SPSS and SEM was run on AMOS. Pearson r correlation and regression tests were run to study the effect of the understudy variables. The study found that both types of connectivity, work- to- family and family- to-work directly influence job and family satisfaction of women. The results suggest that family-friendly policies and organizational support can bring substantial benefits to women workers and the organization as a whole.

  16. Functional connections and pathways of coenzyme Q10-inducible genes: an in-silico study.

    Science.gov (United States)

    Schmelzer, Constance; Lindner, Inka; Vock, Christina; Fujii, Kenji; Döring, Frank

    2007-10-01

    Coenzyme Q10 (CoQ10, ubiquinone) is an essential cofactor in the electron transport chain, serves as a potent antioxidant in mitochondria and lipid membranes, and is often used as a dietary supplement for a number of diseases including cardiovascular diseases. Recently, we obtained evidence that CoQ10 (Kaneka Q10) affects the expression of hundreds of human genes. To decipher the functional and regulatory connections of these genes, a literature search combined with transcription factor binding site analysis was performed using Genomatix BiblioSphere and MatInspector. This in-silico analysis revealed 17 CoQ10-inducible genes which are functionally connected by signalling pathways of G-protein coupled receptors, JAK/STAT, integrin, and beta-arrestin. Promoter analysis of these CoQ10-inducible genes showed one group of NF B-regulated genes, namely IL5, thrombin, vitronectin receptor and C-reactive protein (CRP). Furthermore, a common promoter framework containing binding sites of the transcription factor families EVI1, HOXF, HOXC, and CLOX was identified in the promoters of IL5, CRP, and vitronectin receptor. The identified CoQ10-inducible genes and pathways play an important role in inflammatory response. Since these effects are based on an in-vitro study, the effect of CoQ10 on vascular health in vivo needs to be addressed in further animal and/or human intervention studies.

  17. Torsional vibration characteristic study of the grid-connected DFIG wind turbine

    Science.gov (United States)

    Yu, Songtao; Xie, Da; Wu, Wangping; Gu, Chenghong; Li, Furong

    2017-01-01

    This paper studies the torsional vibration characteristics of the grid-connected doubly-fed induction generator (DFIG) wind turbine by small signal analysis method. Firstly a detailed small-signal stability union model of the grid-connected DFIG wind turbine is developed, including the mechanical system and electrical system. To study the dynamic characteristic of the blade, gearbox, low speed and high speed shafts, a three mass shaft model for the mechanical system is adopted. At the same time, small signal models of DFIG, the voltage source converter (VSC) and the transmission line of the electrical system are developed respectively. Then, through calculating the eigenvalues of the state matrix A and the corresponding participation factors, the modal analysis is conducted in the shaft torsional vibration issues. And the impact of the system parameters including the series compensation capacitor, the flat-wave reactor, the PI parameters, especially the speed controller of generator rotor on shaft torsional vibration are discussed. The results show that the speed controller strengthens association between the mechanical system and the electrical system, and also produces a low-frequency oscillation mode.

  18. Feasibility Study of Grid Connected PV-Biomass Integrated Energy System in Egypt

    Science.gov (United States)

    Barakat, Shimaa; Samy, M. M.; Eteiba, Magdy B.; Wahba, Wael Ismael

    2016-10-01

    The aim of this paper is to present a feasibility study of a grid connected photovoltaic (PV) and biomass Integrated renewable energy (IRE) system providing electricity to rural areas in the Beni Suef governorate, Egypt. The system load of the village is analyzed through the environmental and economic aspects. The model has been designed to provide an optimal system configuration based on daily data for energy availability and demands. A case study area, Monshaet Taher village (29° 1' 17.0718"N, 30° 52' 17.04"E) is identified for economic feasibility in this paper. HOMER optimization model plan imputed from total daily load demand, 2,340 kWh/day for current energy consuming of 223 households with Annual Average Insolation Incident on a Horizontal Surface of 5.79 (kWh/m2/day) and average biomass supplying 25 tons / day. It is found that a grid connected PV-biomass IRE system is an effective way of emissions reduction and it does not increase the investment of the energy system.

  19. Quantifying the link between anatomical connectivity, gray matter volume and regional cerebral blood flow: an integrative MRI study.

    Directory of Open Access Journals (Sweden)

    Bálint Várkuti

    Full Text Available BACKGROUND: In the graph theoretical analysis of anatomical brain connectivity, the white matter connections between regions of the brain are identified and serve as basis for the assessment of regional connectivity profiles, for example, to locate the hubs of the brain. But regions of the brain can be characterised further with respect to their gray matter volume or resting state perfusion. Local anatomical connectivity, gray matter volume and perfusion are traits of each brain region that are likely to be interdependent, however, particular patterns of systematic covariation have not yet been identified. METHODOLOGY/PRINCIPAL FINDINGS: We quantified the covariation of these traits by conducting an integrative MRI study on 23 subjects, utilising a combination of Diffusion Tensor Imaging, Arterial Spin Labeling and anatomical imaging. Based on our hypothesis that local connectivity, gray matter volume and perfusion are linked, we correlated these measures and particularly isolated the covariation of connectivity and perfusion by statistically controlling for gray matter volume. We found significant levels of covariation on the group- and regionwise level, particularly in regions of the Default Brain Mode Network. CONCLUSIONS/SIGNIFICANCE: Connectivity and perfusion are systematically linked throughout a number of brain regions, thus we discuss these results as a starting point for further research on the role of homology in the formation of functional connectivity networks and on how structure/function relationships can manifest in the form of such trait interdependency.

  20. Migration of Tidal Inlets of Chilika Lagoon, Odisha, India -A Critical Study

    Directory of Open Access Journals (Sweden)

    Siba Prasad Mishra

    2014-10-01

    Full Text Available Chilika Lake, Asia’s largest brackish water lagoon situated on the East coast of India is separated from Bay of Bengal by sand bars and connected with the sea by a series of tidal inlets. The inlets are maintained by discharges of inflowing streams during monsoon and by tides and ebb tides during non-monsoon. Imbalance in ingress and egress of sediment due to their continuous exchange between sea and the lagoon causes sedimentation of lagoon. Varying inflow, littoral drift and such other factors influence sedimentation. It results shifting mouths (inlets continuously. Some mouths closed and some opened at various locations of the spits of the lagoon in course of time. This governs the inflow and the outflow characteristics and hence the salinity. A barrage at Naraj on Kathajodi, a major distributary of the river Mohanadi, and an artificial channel connecting the mouth of the Lagoon from Magarmunha to Bay of Bengal were provided to regulate the inflow. This phenomenon has been studied critically considering long history, geophysical parameters, terrestrial events and human interventions etc. Since the activities are location based, exact hydrodynamics has not yet been established for formation, closure and shifting of the tidal inlets. The present study deals with mouthing activities with time, the mechanism involved and effect of Naraj barrage on closure, migration and opening of new tidal inlets in Chilika Lagoon. The possible effects of celestial bodies and sun-earth geometry, which were unnoticed so far, are studied.

  1. General survey and conclusions with regard to the connection of water quantity and water quality studies of surface waters

    NARCIS (Netherlands)

    Rijtema, P.E.

    1979-01-01

    Publikatie die bestaat uit twee delen: 1. General survey of the relation between water quantity and water quality; 2. Conclusions with regard to the connection of water quantity and water quality studies of surface waters

  2. Who Is the Best Connected Scientist?A Study of Scientific Coauthorship Networks

    Science.gov (United States)

    Newman, Mark E. J.

    Using data from computer databases of scientific papers in physics, biomedical research, and computer science, we have constructed networks of collaboration between scientists in each of these disciplines. In these networks two scientists are considered connected if they have coauthored one or more papers together. We have studied many statistical properties of our networks, including numbers of papers written by authors, numbers of authors per paper, numbers of collaborators that scientists have, typical distance through the network from one scientist to another, and a variety of measures of connectedness within a network, such as closeness and betweenness. We further argue that simple networks such as these cannot capture the variation in the strength of collaborative ties and propose a measure of this strength based on the number of papers coauthored by pairs of scientists, and the number of other scientists with whom they worked on those papers. Using a selection of our results, we suggest a variety of possible ways to answer the question Who is the best connected scientist?

  3. Music and emotion: an EEG connectivity study in patients with disorders of consciousness.

    Science.gov (United States)

    Varotto, G; Fazio, P; Rossi Sebastiano, D; Avanzini, G; Franceschetti, S; Panzica, F; CRC

    2012-01-01

    Human emotion perception is a topic of great interest for both cognitive and clinical neuroscience, but its electrophysiological correlates are still poorly understood. The present study is aimed at evaluating if measures of synchronization and indexes based on graph-theory are a tool suitable to study and quantify electrophysiological changes due to emotional stimuli perception. In particular, our study is aimed at evaluating if different EEG connectivity patterns can be induced by pleasant (consonant) or unpleasant (dissonant) music, in a population of healthy subjects, and in patients with severe disorders of consciousness (DOCs), namely vegetative state (VS) patients. In the control group, pleasant music induced an increase in network number of connections, compared with the resting condition, while no changes were caused by the unpleasant stimuli. However, clustering coefficient and path length, two indexes derived from graph theory, able to characterise segregation and integration properties of a network, were not affected by the stimuli, neither pleasant nor unpleasant. In the VS group, changes were found only in those patients with the less severe consciousness impairment, according to the clinical assessment. In these patients a stronger synchronization was found during the unpleasant condition; moreover we observed changes in the network topology, with decreased values of clustering coefficient and path length during both musical stimuli.Our results show that measures of synchronization can provide new insights into the study of the electro physiological correlates of emotion perception, indicating that these tools can be used to study patients with DOCs, in whom the issue of objective measures and quantification of the degree of impairment is still an open and unsolved question.

  4. Cutaneous manifestations of mixed connective tissue disease: Study from a tertiary care hospital in Eastern India

    Directory of Open Access Journals (Sweden)

    Sumit Sen

    2014-01-01

    Full Text Available Context: Mixed connective tissue disorder is an uncommon disease. Some scientists are reluctant to recognize it as a separate entity. Some others have defined this ailment. Cutaneous features of this condition are unique. Researchers from India have described these features to relate to those described in the studies from other parts of the globe. Aims: This study aims to delineate the skin manifestations of clearly defined mixed connective tissue disease (MCTD patients, to compare them with those established as overlap syndrome, and to relate them with studies from other parts of the globe. Settings and Design: Successive patients who fulfilled the specific criteria for MCTD presenting in the skin outpatient department of a tertiary care hospital in eastern India were clinically examined from 2009 for 3 years. Materials and Methods: The number of participants was 23 and the dermatological features of these were compared with 22 patients with overlap syndrome. The antibody to uridine-rich U1 ribonucleoprotein was measured for all patients. Statistical Analysis Used: SPSS (Version 17 and MedCalc (Version 11.6. Results: The Male: Female ratio among the MCTD patients was 1:6.67 and that of the overlap syndrome was 1:10. Twenty patients of the MCTD group presented with synovitis as against only seven in the overlap group. Raynaud′s phenomenon was present in some of the subjects. Puffy fingers were rare in our study. Facial numbness was reported by four of those suffering from MCTD. Antinuclear antibody (ANA was essentially of a speckled pattern in this disease Conclusions: Cutaneous indicators of MCTD are distinct from overlap syndrome. Knowledge of these manifestations prevalent in a region may lead to early diagnosis of the disease.

  5. Virtual house calls for Parkinson disease (Connect.Parkinson): study protocol for a randomized, controlled trial.

    Science.gov (United States)

    Achey, Meredith A; Beck, Christopher A; Beran, Denise B; Boyd, Cynthia M; Schmidt, Peter N; Willis, Allison W; Riggare, Sara S; Simone, Richard B; Biglan, Kevin M; Dorsey, E Ray

    2014-11-27

    Interest in improving care for the growing number of individuals with chronic conditions is rising. However, access to care is limited by distance, disability, and distribution of doctors. Small-scale studies in Parkinson disease, a prototypical chronic condition, have suggested that delivering care using video house calls is feasible, offers similar clinical outcomes to in-person care, and reduces travel burden. We are conducting a randomized comparative effectiveness study (Connect.Parkinson) comparing usual care in the community to usual care augmented by virtual house calls with a Parkinson disease specialist. Recruitment is completed centrally using online advertisements and emails and by contacting physicians, support groups, and allied health professionals. Efforts target areas with a high proportion of individuals not receiving care from neurologists. Approximately 200 individuals with Parkinson disease and their care partners will be enrolled at 20 centers throughout the United States and followed for one year. Participants receive educational materials, then are randomized in a 1:1 ratio to continue their usual care (control arm) or usual care and specialty care delivered virtually (intervention arm). Care partners are surveyed about their time and travel burden and their perceived caregiver burden. Participants are evaluated via electronic survey forms and videoconferencing with a blinded independent rater at baseline and at 12 months. All study activities are completed remotely.The primary outcomes are: (1) feasibility, as measured by the proportion of visits completed, and (2) quality of life, as measured by the 39-item Parkinson's Disease Questionnaire. Secondary outcomes include measures of clinical benefit, quality of care, time and travel burden, and caregiver burden. Connect.Parkinson will evaluate the feasibility and effectiveness of using technology to deliver care into the homes of individuals with Parkinson disease. The trial may serve as a

  6. Model-free functional connectivity and impulsivity correlates of alcohol dependence: a resting-state study.

    Science.gov (United States)

    Zhu, Xi; Cortes, Carlos R; Mathur, Karan; Tomasi, Dardo; Momenan, Reza

    2017-01-01

    Alcohol dependence is characterized by impulsiveness toward consumption despite negative consequences. Although neuro-imaging studies have implicated some regions underlying this disorder, there is little information regarding its large-scale connectivity pattern. This study investigated the within- and between-network functional connectivity (FC) in alcohol dependence and examined its relationship with clinical impulsivity measures. Using probabilistic independent component analysis on resting-state functional magnetic resonance imaging (rs-fMRI) data from 25 alcohol-dependent (AD) and 26 healthy control (HC) participants, we compared the within- and between-network FC between AD and HC. Then, the relationship between FC and impulsiveness as measured by the Barratt Impulsiveness Scale (BIS-11), the UPPS-P Impulsive Scale and the delay discounting task (DDT), was explored. Compared with HC, AD exhibited increased within-network FC in salience (SN), default mode (DMN), orbitofrontal cortex (OFCN), left executive control (LECN) and amygdala-striatum (ASN) networks. Increased between-network FC was found among LECN, ASN and SN. Between-network FC correlations were significantly negative between Negative-Urgency and OFCN pairs with right executive control network (RECN), anterior DMN (a-DMN) and posterior DMN (p-DMN) in AD. DDT was significantly correlated with the between-network FC among the LECN, a-DMN and SN in AD. These findings add evidence to the concept of altered within-network FC and also highlight the role of between-network FC in the pathophysiology of AD. Additionally, this study suggests differential neurobiological bases for different clinical measures of impulsivity that may be used as a systems-level biomarker for alcohol dependence severity and treatment efficacy.

  7. Changes of functional and effective connectivity in smoking replenishment on deprived heavy smokers: a resting-state FMRI study.

    Science.gov (United States)

    Ding, Xiaoyu; Lee, Seong-Whan

    2013-01-01

    Previous researches have explored the changes of functional connectivity caused by smoking with the aid of fMRI. This study considers not only functional connectivity but also effective connectivity regarding both brain networks and brain regions by using a novel analysis framework that combines independent component analysis (ICA) and Granger causality analysis (GCA). We conducted a resting-state fMRI experiment in which twenty-one heavy smokers were scanned in two sessions of different conditions: smoking abstinence followed by smoking satiety. In our framework, group ICA was firstly adopted to obtain the spatial patterns of the default-mode network (DMN), executive-control network (ECN), and salience network (SN). Their associated time courses were analyzed using GCA, showing that the effective connectivity from SN to DMN was reduced and that from ECN/DMN to SN was enhanced after smoking replenishment. A paired t-test on ICA spatial patterns revealed functional connectivity variation in regions such as the insula, parahippocampus, precuneus, anterior cingulate cortex, supplementary motor area, and ventromedial/dorsolateral prefrontal cortex. These regions were later selected as the regions of interest (ROIs), and their effective connectivity was investigated subsequently using GCA. In smoking abstinence, the insula showed the increased effective connectivity with the other ROIs; while in smoking satiety, the parahippocampus had the enhanced inter-area effective connectivity. These results demonstrate our hypothesis that for deprived heavy smokers, smoking replenishment takes effect on both functional and effective connectivity. Moreover, our analysis framework could be applied in a range of neuroscience studies.

  8. Connected Traveler

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Alex

    2015-11-01

    The Connected Traveler project is a multi-disciplinary undertaking that seeks to validate potential for transformative transportation system energy savings by incentivizing efficient traveler behavior. This poster outlines various aspects of the Connected Traveler project, including market opportunity, understanding traveler behavior and decision-making, automation and connectivity, and a projected timeline for Connected Traveler's key milestones.

  9. Mild cognitive impairment and fMRI studies of brain functional connectivity: the state of the art

    Science.gov (United States)

    Farràs-Permanyer, Laia; Guàrdia-Olmos, Joan; Peró-Cebollero, Maribel

    2015-01-01

    In the last 15 years, many articles have studied brain connectivity in Mild Cognitive Impairment patients with fMRI techniques, seemingly using different connectivity statistical models in each investigation to identify complex connectivity structures so as to recognize typical behavior in this type of patient. This diversity in statistical approaches may cause problems in results comparison. This paper seeks to describe how researchers approached the study of brain connectivity in MCI patients using fMRI techniques from 2002 to 2014. The focus is on the statistical analysis proposed by each research group in reference to the limitations and possibilities of those techniques to identify some recommendations to improve the study of functional connectivity. The included articles came from a search of Web of Science and PsycINFO using the following keywords: f MRI, MCI, and functional connectivity. Eighty-one papers were found, but two of them were discarded because of the lack of statistical analysis. Accordingly, 79 articles were included in this review. We summarized some parts of the articles, including the goal of every investigation, the cognitive paradigm and methods used, brain regions involved, use of ROI analysis and statistical analysis, emphasizing on the connectivity estimation model used in each investigation. The present analysis allowed us to confirm the remarkable variability of the statistical analysis methods found. Additionally, the study of brain connectivity in this type of population is not providing, at the moment, any significant information or results related to clinical aspects relevant for prediction and treatment. We propose to follow guidelines for publishing fMRI data that would be a good solution to the problem of study replication. The latter aspect could be important for future publications because a higher homogeneity would benefit the comparison between publications and the generalization of results. PMID:26300802

  10. Mild cognitive impairment and fMRI studies of brain functional connectivity: the state of the art

    Directory of Open Access Journals (Sweden)

    Laia eFarràs-Permanyer

    2015-08-01

    Full Text Available In the last fifteen years, many articles have studied brain connectivity in Mild Cognitive Impairment patients with fMRI techniques, seemingly using different connectivity statistical models in each investigation to identify complex connectivity structures so as to recognize typical behavior in this type of patient. This diversity in statistical approaches may cause problems in results comparison. This paper seeks to describe how researchers approached the study of brain connectivity in MCI patients using fMRI techniques from 2002 to 2014.The focus is on the statistical analysis proposed by each research group in reference to the limitations and possibilities of those techniques to identify some recommendations to improve the study of functional connectivity. The included articles came from a search of Web of Science and PsycINFO using the following keywords: fMRI, MCI and functional connectivity. Eighty-one papers were found, but 2 of them were discarded because of the lack of statistical analysis. Accordingly, 79 articles were included in this review. We summarized some parts of the articles, including the goal of every investigation, the cognitive paradigm and methods used, brain regions involved, use of ROI analysis and statistical analysis, emphasizing on the connectivity estimation model used in each investigation. The present analysis allowed us to confirm the remarkable variability of the statistical analysis methods found. Additionally, the study of brain connectivity in this type of population is not providing, at the moment, any significant information or results related to clinical aspects relevant for prediction and treatment. We propose to follow guidelines for publishing fMRI data that would be a good solution to the problem of study replication. The latter aspect could be important for future publications because a higher homogeneity would benefit the comparison between publications and the generalization of results.

  11. Mild cognitive impairment and fMRI studies of brain functional connectivity: the state of the art.

    Science.gov (United States)

    Farràs-Permanyer, Laia; Guàrdia-Olmos, Joan; Peró-Cebollero, Maribel

    2015-01-01

    In the last 15 years, many articles have studied brain connectivity in Mild Cognitive Impairment patients with fMRI techniques, seemingly using different connectivity statistical models in each investigation to identify complex connectivity structures so as to recognize typical behavior in this type of patient. This diversity in statistical approaches may cause problems in results comparison. This paper seeks to describe how researchers approached the study of brain connectivity in MCI patients using fMRI techniques from 2002 to 2014. The focus is on the statistical analysis proposed by each research group in reference to the limitations and possibilities of those techniques to identify some recommendations to improve the study of functional connectivity. The included articles came from a search of Web of Science and PsycINFO using the following keywords: f MRI, MCI, and functional connectivity. Eighty-one papers were found, but two of them were discarded because of the lack of statistical analysis. Accordingly, 79 articles were included in this review. We summarized some parts of the articles, including the goal of every investigation, the cognitive paradigm and methods used, brain regions involved, use of ROI analysis and statistical analysis, emphasizing on the connectivity estimation model used in each investigation. The present analysis allowed us to confirm the remarkable variability of the statistical analysis methods found. Additionally, the study of brain connectivity in this type of population is not providing, at the moment, any significant information or results related to clinical aspects relevant for prediction and treatment. We propose to follow guidelines for publishing fMRI data that would be a good solution to the problem of study replication. The latter aspect could be important for future publications because a higher homogeneity would benefit the comparison between publications and the generalization of results.

  12. Systematic Angular Study of Magnetoresistance in Permalloy Connected Kagome Artificial Spin Ice

    Science.gov (United States)

    Park, Jungsik; Le, Brian; Watts, Justin; Leighton, Chris; Samarth, Nitin; Schiffer, Peter

    Artificial spin ices are nanostructured two-dimensional arrays of ferromagnetic elements, where frustrated interactions lead to unusual collective magnetic behavior. Here we report a room-temperature magnetoresistance study of connected permalloy (Ni81Fe19) kagome artificial spin ice networks, wherein the direction of the applied in-plane magnetic field is systematically varied. We measure both the longitudinal and transverse magnetoresistance in these structures, and we find certain transport geometries of the network show strong angular sensitivity - even small variations in the applied field angle lead to dramatic changes of the magnetoresistance response. We also investigate the magnetization reversal of the networks using magnetic force microscopy (MFM), demonstrating avalanche behavior in the magnetization reversal. The magnetoresistance features are analyzed using an anisotropic magnetoresistance (AMR) model. Supported by the US Department of Energy. Work at the University of Minnesota was supported by Seagate Technology, NSF MRSEC, and a Marie Curie International Outgoing Fellowship within the 7th European Community Framework Programme.

  13. Connection of Farmland Consolidation Construction Works in Northern Anhui Plain:A Case Study of Si County of Anhui Province

    Institute of Scientific and Technical Information of China (English)

    Wei HE; Zhongxiang YU; Chen YAO

    2016-01-01

    The connection of farmland consolidation construction works was studied,to provide theoretical and practical basis for bringing into play optimal functions.It employed theoretical analysis method,case analysis method,and experience summary method.Through empirical study of Si County in Anhui Province,it further analyzed connection of four works:land consolidation,irrigation and drainage,field roads,farmland protection,and ecological and environmental protection,to provide methods and possibilities for coordination and connection of four works.It is required to take the land consolidation as a system,take full consideration of all aspects,attach great importance to connection of four works,so as to bring into full play optimal functions and realize sustainable use of land resources and sustainable development of social economy.

  14. Connecting primary care clinics and community pharmacies through a nationwide electronic prescribing network: A qualitative study

    Directory of Open Access Journals (Sweden)

    Marie-Pierre Gagnon

    2015-10-01

    Full Text Available Background The use of medication is at the heart of primary care, but is also the cause for major health concerns. It is therefore important to examine the prescription of medication process.Objective This study identifies the barriers and facilitators perceived by community pharmacists and primary care physicians concerning the adoption of a nationwide electronic prescribing (e-prescribing network in the province of Quebec, Canada.Methods We used purposive sampling to identify the most intensive users of the e-prescribing network. We conducted phone and in-person interviews. Interviews were transcribed, and we analysed their content with NVivo, using the clinical adoption framework (CAF for the codification of the data.Results We interviewed 33 pharmacists, 2 pharmacy technicians, 11 physicians and 3 clinic managers. Adoption of the e-prescribing network was fairly low. The respondents underlined adaptation of their work environment, openness to change and perception of benefits as facilitators to the adoption of the network. However, important barriers were perceived, including system quality issues and paper prescriptions being the only legal document in the prescribing process. Even if respondents recognised that the e-prescribing network can offer substantial benefits to the prescribing process, issues still persisted and raised barriers to the full use of such a network, especially in a context where different local information systems are connected within a nationwide e-prescribing network.Conclusion This study, based on the CAF, provides a better understanding of the factors related to the adoption of a nationwide e-prescribing network connecting primary care clinics and community pharmacies. 

  15. Ventral medial prefrontal functional connectivity and emotion regulation in chronic schizophrenia: A pilot study

    Institute of Scientific and Technical Information of China (English)

    Feng-Mei Fan; Shu-Ping Tan; Fu-De Yang; Yun-Long Tan; Yan-Li Zhao; Nan Chen; Bin-Bin Li

    2013-01-01

    People with schizophrenia exhibit impaired social cognitive functions,particularly emotion regulation.Abnormal activations of the ventral medial prefrontal cortex (vMPFC) during emotional tasks have been demonstrated in schizophrenia,suggesting its important role in emotion processing in patients.We used the resting-state functional connectivity approach,setting a functionally relevant region,the vMPFC,as a seed region to examine the intrinsic functional interactions and communication between the vMPFC and other brain regions in schizophrenic patients.We found hypo-connectivity between the vMPFC and the medial frontal cortex,right middle temporal lobe (MTL),right hippocampus,parahippocampal cortex (PHC) and amygdala.Further,there was a decreased strength of the negative connectivity (or anticorrelation) between the vMPFC and the bilateral dorsal lateral prefrontal cortex (DLPFC) and pre-supplementary motor areas.Among these connectivity alterations,reduced vMPFCDLPFC connectivity was positively correlated with positive symptoms on the Positive and Negative Syndrome Scale,while vMPFC-right MTL/PHC/amygdala functional connectivity was positively correlated with the performance of emotional regulation in patients.These findings imply that communication and coordination throughout the brain networks are disrupted in schizophrenia.The emotional correlates of vMPFC connectivity suggest a role of the hypo-connectivity between these regions in the neuropathology of abnormal social cognition in chronic schizophrenia.

  16. In the Eye of the Storm : Connectivity studies on antisocial behavior and psychopathy

    NARCIS (Netherlands)

    Hoppenbrouwers, S.S.

    2012-01-01

    This thesis consists of three sections. Section 1 is a proof of principle in which the functional contributions and mechanisms of interhemispheric connectivity will be addressed. The first chapter of Part 1 (§2.1) will examine the relationship between interhemispheric connectivity and personality fe

  17. Ethnopedology in the study of toponyms connected to the indigenous knowledge on soil resource.

    Science.gov (United States)

    Capra, Gian Franco; Ganga, Antonio; Buondonno, Andrea; Grilli, Eleonora; Gaviano, Carla; Vacca, Sergio

    2015-01-01

    In taking an integrated ethnopedological approach, this study aims to investigate the meaning of the distribution of the toponyms used in traditional and recent cartography of Sardinia (southern Italy). It is particularly, but not only, focused on those related to soil resources. Sardinia is particularly interesting in this respect, as its unique history, geography, and linguistic position makes it one of the Italian and Mediterranean regions with the greatest number of toponyms. This research investigated the toponyms belonging to an important sub-region of Sardinia, called Ogliastra (central-eastern Sardinia). The research was conducted through the following integrated approach: i) toponymy research and collection from different sources; ii) database creation and translation of toponyms from the Sardinian language (SL); iii) categorization of toponyms; and iv) graphical, statistical, and cartographic data processing. Distribution and diversity of toponyms were assessed using the compiled database, coupled with a geographical information system (GIS). Of around 7700 toponyms collected, 79% had already been reported in SL, while just 21% were in Italian. Of the toponyms in SL, 77% are of known meaning and 54% of these toponyms were characterized by a meaning directly and/or indirectly connected to specific environmental features. On the whole, morphology would appear to be the primary environmental factor able to explain the complex, articulated presence, distribution, and typology of the investigated toponyms. A least squares regression analysis of pedodiversity vs. topodiversity shows a very closed distribution, with an impressive high correlation index (R2 = 0.824). The principal factor analysis (PFA) shows that such a connection may be morphologically based, thereby confirming that pedodiversity and topodiversity are strongly linked each other. Overall, the research shows that an integrated ethnopedological approach, combining indigenous and scientific

  18. A Case Study in Connectomics: The History, Mapping, and Connectivity of the Claustrum

    Directory of Open Access Journals (Sweden)

    Carinna Margaret Torgerson

    2014-11-01

    Full Text Available The claustrum seems to have been waiting for the science of connectomics. Due to its tiny size, the structure has remained remarkably difficult to study until modern technological and mathematical advancements like graph theory, connectomics, diffusion tensor imaging, HARDI, and excitotoxic lesioning. That does not mean, however, that early methods allowed researchers to assess micro-connectomics. In fact, the claustrum is such an enigma that the only things known for certain about it are its histology, and that it is extraordinarily well connected. In this literature review, we provide background details on the claustrum and the history of its study in the human and in other animal species. By providing an explanation of the neuroimaging and histology methods have been undertaken to study the claustrum thus far – and the conclusions these studies have drawn – we illustrate this example of how the shift from micro-connectomics to macro-connectomics advances the field of neuroscience and improves our capacity to understand the brain.

  19. Disrupted thalamocortical connectivity in PSP: a resting-state fMRI, DTI, and VBM study.

    Science.gov (United States)

    Whitwell, Jennifer L; Avula, Ramesh; Master, Ankit; Vemuri, Prashanthi; Senjem, Matthew L; Jones, David T; Jack, Clifford R; Josephs, Keith A

    2011-09-01

    Progressive supranuclear palsy (PSP) is associated with pathological changes along the dentatorubrothalamic tract and in premotor cortex. We aimed to assess whether functional neural connectivity is disrupted along this pathway in PSP, and to determine how functional changes relate to changes in structure and diffusion. Eighteen probable PSP subjects and 18 controls had resting-state (task-free) fMRI, diffusion tensor imaging and structural MRI. Functional connectivity was assessed between thalamus and the rest of the brain, and within the basal ganglia, salience and default mode networks (DMN). Patterns of atrophy were assessed using voxel-based morphometry, and patterns of white matter tract degeneration were assessed using tract-based spatial statistics. Reduced in-phase functional connectivity was observed between the thalamus and premotor cortex including supplemental motor area (SMA), striatum, thalamus and cerebellum in PSP. Reduced connectivity in premotor cortex, striatum and thalamus were observed in the basal ganglia network and DMN, with subcortical salience network reductions. Tract degeneration was observed between cerebellum and thalamus and in superior longitudinal fasciculus, with grey matter loss in frontal lobe, premotor cortex, SMA and caudate nucleus. SMA functional connectivity correlated with SMA volume and measures of cognitive and motor dysfunction, while thalamic connectivity correlated with degeneration of superior cerebellar peduncles. PSP is therefore associated with disrupted thalamocortical connectivity that is associated with degeneration of the dentatorubrothalamic tract and the presence of cortical atrophy.

  20. Studying the default mode and its mindfulness-induced changes using EEG functional connectivity.

    Science.gov (United States)

    Berkovich-Ohana, Aviva; Glicksohn, Joseph; Goldstein, Abraham

    2014-10-01

    The default mode network (DMN) has been largely studied by imaging, but not yet by neurodynamics, using electroencephalography (EEG) functional connectivity (FC). mindfulness meditation (MM), a receptive, non-elaborative training is theorized to lower DMN activity. We explored: (i) the usefulness of EEG-FC for investigating the DMN and (ii) the MM-induced EEG-FC effects. To this end, three MM groups were compared with controls, employing EEG-FC (-MPC, mean phase coherence). Our results show that: (i) DMN activity was identified as reduced overall inter-hemispheric gamma MPC during the transition from resting state to a time production task and (ii) MM-induced a state increase in alpha MPC as well as a trait decrease in EEG-FC. The MM-induced EEG-FC decrease was irrespective of expertise or band. Specifically, there was a relative reduction in right theta MPC, and left alpha and gamma MPC. The left gamma MPC was negatively correlated with MM expertise, possibly related to lower internal verbalization. The trait lower gamma MPC supports the notion of MM-induced reduction in DMN activity, related with self-reference and mind-wandering. This report emphasizes the possibility of studying the DMN using EEG-FC as well as the importance of studying meditation in relation to it.

  1. Functional connectivity changes in adults with developmental stuttering: a preliminary study using quantitative electro-encephalography

    Science.gov (United States)

    Joos, Kathleen; De Ridder, Dirk; Boey, Ronny A.; Vanneste, Sven

    2014-01-01

    Introduction: Stuttering is defined as speech characterized by verbal dysfluencies, but should not be seen as an isolated speech disorder, but as a generalized sensorimotor timing deficit due to impaired communication between speech related brain areas. Therefore we focused on resting state brain activity and functional connectivity. Method: We included 11 patients with developmental stuttering and 11 age matched controls. To objectify stuttering severity and the impact on quality of life (QoL), we used the Dutch validated Test for Stuttering Severity-Readers (TSS-R) and the Overall Assessment of the Speaker’s Experience of Stuttering (OASES), respectively. Furthermore, we used standardized low resolution brain electromagnetic tomography (sLORETA) analyses to look at resting state activity and functional connectivity differences and their correlations with the TSS-R and OASES. Results: No significant results could be obtained when looking at neural activity, however significant alterations in resting state functional connectivity could be demonstrated between persons who stutter (PWS) and fluently speaking controls, predominantly interhemispheric, i.e., a decreased functional connectivity for high frequency oscillations (beta and gamma) between motor speech areas (BA44 and 45) and the contralateral premotor (BA6) and motor (BA4) areas. Moreover, a positive correlation was found between functional connectivity at low frequency oscillations (theta and alpha) and stuttering severity, while a mixed increased and decreased functional connectivity at low and high frequency oscillations correlated with QoL. Discussion: PWS are characterized by decreased high frequency interhemispheric functional connectivity between motor speech, premotor and motor areas in the resting state, while higher functional connectivity in the low frequency bands indicates more severe speech disturbances, suggesting that increased interhemispheric and right sided functional connectivity is

  2. Resting state functional connectivity changes in adults with developmental stuttering: an initial sLORETA study.

    Directory of Open Access Journals (Sweden)

    Kathleen eJoos

    2014-10-01

    Full Text Available Introduction: Stuttering is defined as speech characterized by verbal dysfluencies, but should not be seen as an isolated speech disorder, but as a generalized sensorimotor timing deficit due to impaired communication between speech related brain areas. Therefore we focused on resting state brain activity and functional connectivity.Method: We included 11 patients with developmental stuttering and 11 age matched controls. To objectify stuttering severity and the impact on the quality of life (QoL, we used the Dutch validated Test for Stuttering Severity-Readers (TSS-R and the Overall Assessment of the Speaker’s Experience of Stuttering (OASES, respectively. Furthermore, we used standardized low resolution brain electromagnetic tomography (sLORETA analyses to look at resting state activity and functional connectivity differences and their correlations with the TSS-R and OASES.Results: No resting state activity differences were identified in comparison to fluently speaking controls or in correlation with stuttering severity or QoL measures. Significant alterations in resting state functional connectivity were found, predominantly interhemispheric, i.e. a decreased functional connectivity for high frequency oscillations (beta and gamma between motor speech areas (BA44 and 45 and the contralateral premotor (BA 6 and motor (BA 4 areas. A positive correlation was found between functional connectivity at low frequency oscillations (theta and alpha and stuttering severity, while a mixed increased and decreased functional connectivity at low and high frequency oscillations correlated with QoL.Discussion: PWS are characterized by decreased high frequency interhemispheric functional connectivity between motor speech, premotor and motor areas in the resting state, while higher functional connectivity in the low frequency bands indicates more severe speech disturbances, suggesting that increased interhemispheric and right sided functional connectivity is

  3. Childhood trauma and emotional processing circuits in schizophrenia: A functional connectivity study.

    Science.gov (United States)

    Cancel, Aïda; Comte, Magali; Boutet, Claire; Schneider, Fabien C; Rousseau, Pierre-François; Boukezzi, Sarah; Gay, Aurélia; Sigaud, Torrance; Massoubre, Catherine; Berna, Fabrice; Zendjidjian, Xavier Y; Azorin, Jean-Michel; Blin, Olivier; Fakra, Eric

    2016-12-13

    Childhood trauma strongly impacts emotional responses in schizophrenia. We have explored an association between early trauma and the amygdala functional connectivity using generalized psychophysiological interaction during an emotional task. Twenty-one schizophrenia patients and twenty-five controls were included. In schizophrenia patients, higher levels of sexual abuse and physical neglect during childhood were associated with decreased connectivity between the amygdala and the posterior cingulate/precuneus region. Additionally, patients showed decreased coupling between the amygdala and the posterior cingulate/precuneus region compared to controls. These findings suggest that early trauma could impact later connectivity in specific stress-related circuits affecting self-consciousness and social cognition in schizophrenia.

  4. Intrinsic brain connectivity in chronic pain: A resting-state fMRI study in patients with rheumatoid arthritis.

    Directory of Open Access Journals (Sweden)

    Pär eFlodin

    2016-03-01

    Full Text Available AbstractBackground. Rheumatoid arthritis (RA is commonly accompanied by pain that is discordant with the degree of peripheral pathology. Very little is known about the cerebral processes involved in pain processing in RA. Here we investigated resting-state brain connectivity associated with prolonged pain in RA. Methods. 24 RA subjects and 19 matched controls were compared with regard to both behavioral measures of pain perception and resting-resting state fMRI data acquired subsequently to fMRI sessions involving pain stimuli. The resting-state fMRI brain connectivity was investigated using 159 seed regions located in cardinal pain processing brain regions. Additional principal component based multivariate pattern analysis of the whole brain connectivity pattern was carried out in a data driven analysis to localize group differences in functional connectivity. Results. When RA patients were compared to controls, we observed significantly lower pain resilience for pressure on the affected finger joints (i.e. P50-joint and an overall heightened level of perceived global pain in RA patients. Relative to controls, RA patients displayed increased brain connectivity predominately for the supplementary motor areas, mid-cingulate cortex and the primary sensorimotor cortex. Additionally, we observed an increase in brain connectivity between the insula and prefrontal cortex as well as between anterior cingulate cortex and occipital areas for RA patients. None of the group differences in brain connectivity were significantly correlated with behavioral parameters.Conclusion. Our study provides experimental evidence of increased connectivity between frontal midline regions that are implicated in affective pain processing and bilateral sensorimotor regions in RA patients.

  5. Brain Resting-State Functional Connectivity Is Preserved Under Sevoflurane Anesthesia in Patients with Pervasive Developmental Disorders: A Pilot Study.

    Science.gov (United States)

    Venkatraghavan, Lakshmikumar; Bharadwaj, Suparna; Wourms, Vincent; Tan, Audrey; Jurkiewicz, Michael T; Mikulis, David J; Crawley, Adrian P

    2017-05-01

    Functional connectivity studies play a huge role in understanding the relationship between the network connections and the behavioral phenotype of patients with pervasive developmental disorders (PDD). Some patients with PDD may not be able to tolerate the imaging procedure while they are awake, and, hence, they often need general anesthesia. General anesthesia is a confounding factor in functional imaging studies due to its effect on the functional connectivity. The objective of this study is to look at the resting-state functional connectivity (RS-FC) under sevoflurane anesthesia in patients with PDDs. Thirteen adults with PDD scheduled for magnetic resonance imaging (MRI) of the brain under general anesthesia were recruited for the study. Resting-state functional MRI (fMRI) scans were acquired at 1 minimum alveolar concentration (MAC) of sevoflurane. Spontaneous blood oxygenation level-dependent fluctuations were measured, and a seed-voxel analysis was done to identify the resting-state networks. Subjects' data were compared with data from 16 nonanesthetized healthy controls. Six networks (default mode network [DMN], executive control network [ECN], salience network [SN], auditory, visual, and sensorimotor) were investigated. At 1 MAC sevoflurane anesthesia, RS-FC was preserved in all the networks. Secondary analysis of connectivity showed a decrease in connectivity within the thalamus and an increase in DMN-ECN and DMN-SN cross-network connectivity in the anesthetized patient group compared to healthy controls. Previous reports suggested that even mild levels of anesthesia could reduce overall fluctuation levels in the major brain. However, our results provide strong evidence that most networks can sustain detectable levels of activity in patients with PDDs even under deep levels of anesthesia.

  6. Alveolar Ridge Contouring with Free Connective Tissue Graft at Implant Placement: A 5-Year Consecutive Clinical Study.

    Science.gov (United States)

    Hanser, Thomas; Khoury, Fouad

    2016-01-01

    This study evaluated volume stability after alveolar ridge contouring with free connective tissue grafts at implant placement in single-tooth gaps. A total of 52 single-tooth gaps with labial volume deficiencies in the maxilla (incisors, canines, and premolars) were consecutively treated with implants and concomitant free palatal connective tissue grafts in 46 patients between 2006 and 2009. Implants had to be covered with at least 2 mm peri-implant local bone after insertion. At implant placement, a free connective tissue graft from the palate was fixed inside a labial split-thickness flap to form an existing concave buccal alveolar ridge contour due to tissue volume deficiency into a convex shape. Standardized volumetric measurements of the labial alveolar contour using a template were evaluated before connective tissue grafting and at 2 weeks, 1 year, and 5 years after implantprosthetic incorporation. Tissue volume had increased significantly (P tissue contour of the implant before connective tissue grafting to baseline (2 weeks after implant-prosthetic incorporation). Statistically, 50% of the reference points (P > .05) kept their volume from baseline to 1 year after prosthetic incorporation and from baseline to 5 years after prosthetic incorporation, respectively, whereas reference points located within the area of the implant sulcus showed a significant (P connective tissue grafting appears to be an appropriate long-term means to contour preexisting buccal alveolar volume deficiencies in single implants.

  7. Observational Study on Connection between Sprites and TGFs with GRT-WF

    Science.gov (United States)

    Watanabe, Ken; Sakamoto, Takanori; Hegley, Jakob; Schlitz, Joseph; Vydra, Ekaterina; Okajima, Takashi; Gehrels, Neil

    2016-04-01

    Although it is known that terrestrial gamma-ray flashes (TGFs) can be caused by the electron-cosmic ray Bremsstrahlung in the presence of the Earth magnetic field, the acceleration process of electrons in the Earth atmosphere is not clearly understood. On the other hand, electrons inside thunderclouds produce lightnings (under the clouds) as well as sprites (above the clouds). We study the connection between sprites and TGFs since both of them require free atmospheric electrons. We constructed Goddard Robotic Telescope - Wide Field (GRT-WF) in June 2011, which is composed of seven wide field optical camera located at Florida Gulf Coast University (FGCU), to observe sprites in all the sky. We have recorded about 600 sprites so far, and studied possible associations with TGFs detected by NASA’s Fermi/GBM and RHESSI. The location of GRT-WF has been chosen because the area is one of the highest TGF detection regions by Fermi/GBM (others are Africa and South-East Asia).

  8. Invasive pulmonary fungal infections in patients with connective tissue disease: a retrospective study from northern China

    Directory of Open Access Journals (Sweden)

    H.F. Ge

    Full Text Available Invasive pulmonary fungal infection (IPFI is a potentially fatal complication in patients with connective tissue disease (CTD. The current study aimed to uncover the clinical characteristics and risk factors of patients with IPFI-CTD. The files of 2186 CTD patients admitted to a single center in northern China between January 2011 and December 2013 were retrospectively reviewed. A total of 47 CTD patients with IPFI were enrolled into this study and assigned to the CTD-IPFI group, while 47 uninfected CTD patients were assigned to the control group. Clinical manifestations were recorded, and risk factors of IPFI were calculated by stepwise logistical regression analysis. Forty-seven (2.15% CTD patients developed IPFI. Systemic lupus erythematosus patients were responsible for the highest proportion (36.17% of cases with IPFI. Candida albicans (72.3% accounted for the most common fungal species. CTD-IPFI patients had significantly elevated white blood cell count, erythrocyte sedimentation rate, C-reactive protein and fasting glucose values compared to controls (P<0.05. Cough, sputum and blood in phlegm were the most common symptoms. Risk factors of IPFI in CTD included maximum prednisone dose ≥30 mg/day within 3 months prior to infection, anti-microbial drug therapy, and interstitial pneumonia. CTD patients who have underlying interstitial pneumonia, prior prednisone or multiple antibiotics, were more likely to develop IPFI.

  9. Connecting Grammaticalisation

    DEFF Research Database (Denmark)

    Nørgård-Sørensen, Jens; Heltoft, Lars; Schøsler, Lene

    morphological, topological and constructional paradigms often connect to form complex paradigms. The book introduces the concept of connecting grammaticalisation to describe the formation, restructuring and dismantling of such complex paradigms. Drawing primarily on data from Germanic, Romance and Slavic...

  10. Making Theory-Practice Connections in a Social Studies Methods Course: A Case Study.

    Science.gov (United States)

    van 't Hooft, Mark

    This study investigated whether or not students apply educational theory to practical situations when they are involved in a learning process that starts from their own educational experiences and "Gestalts," the holistic unity of knowledge, feelings, values, and meanings linked to concrete situations encountered before, and colored by…

  11. A Study of Method on Connectivity Analysis of Between Software Components

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An analysis and computation method of conne ctivity betweencomponents that based on logical subtyping is first presented, t he concepts of virtual interface and real interface, and quantitative analy sis and computation formula of connectivity between interfaces are also introduc ed, that based on a extendable software architecture specification language model. We provide a n ew idea for solving the problem of connection between reuse-components.

  12. Structural connectivity of the human anterior temporal lobe: A diffusion magnetic resonance imaging study.

    Science.gov (United States)

    Papinutto, Nico; Galantucci, Sebastiano; Mandelli, Maria Luisa; Gesierich, Benno; Jovicich, Jorge; Caverzasi, Eduardo; Henry, Roland G; Seeley, William W; Miller, Bruce L; Shapiro, Kevin A; Gorno-Tempini, Maria Luisa

    2016-06-01

    The anterior temporal lobes (ATL) have been implicated in a range of cognitive functions including auditory and visual perception, language, semantic knowledge, and social-emotional processing. However, the anatomical relationships between the ATLs and the broader cortical networks that subserve these functions have not been fully elucidated. Using diffusion tensor imaging (DTI) and probabilistic tractography, we tested the hypothesis that functional segregation of information in the ATLs is reflected by distinct patterns of structural connectivity to regions outside the ATLs. We performed a parcellation of the ATLs bilaterally based on the degree of connectivity of each voxel with eight ipsilateral target regions known to be involved in various cognitive networks. Six discrete segments within each ATL showed preferential connectivity to one of the ipsilateral target regions, via four major fiber tracts (uncinate, inferior longitudinal, middle longitudinal, and arcuate fasciculi). Two noteworthy interhemispheric differences were observed: connections between the ATL and orbito-frontal areas were stronger in the right hemisphere, while the consistency of the connection between the ATL and the inferior frontal gyrus through the arcuate fasciculus was greater in the left hemisphere. Our findings support the hypothesis that distinct regions within the ATLs have anatomical connections to different cognitive networks. Hum Brain Mapp 37:2210-2222, 2016. © 2016 Wiley Periodicals, Inc.

  13. Functional connectivity in the first year of life in infants at risk for autism spectrum disorder: an EEG study.

    Science.gov (United States)

    Righi, Giulia; Tierney, Adrienne L; Tager-Flusberg, Helen; Nelson, Charles A

    2014-01-01

    In the field of autism research, recent work has been devoted to studying both behavioral and neural markers that may aide in early identification of autism spectrum disorder (ASD). These studies have often tested infants who have a significant family history of autism spectrum disorder, given the increased prevalence observed among such infants. In the present study we tested infants at high- and low-risk for ASD (based on having an older sibling diagnosed with the disorder or not) at 6- and 12-months-of-age. We computed intrahemispheric linear coherence between anterior and posterior sites as a measure of neural functional connectivity derived from electroencephalography while the infants were listening to speech sounds. We found that by 12-months-of-age infants at risk for ASD showed reduced functional connectivity compared to low risk infants. Moreover, by 12-months-of-age infants later diagnosed with ASD showed reduced functional connectivity, compared to both infants at low risk for the disorder and infants at high risk who were not later diagnosed with ASD. Significant differences in functional connectivity were also found between low-risk infants and high-risk infants who did not go onto develop ASD. These results demonstrate that reduced functional connectivity appears to be related to genetic vulnerability for ASD. Moreover, they provide further evidence that ASD is broadly characterized by differences in neural integration that emerge during the first year of life.

  14. Functional connectivity in the first year of life in infants at risk for autism spectrum disorder: an EEG study.

    Directory of Open Access Journals (Sweden)

    Giulia Righi

    Full Text Available In the field of autism research, recent work has been devoted to studying both behavioral and neural markers that may aide in early identification of autism spectrum disorder (ASD. These studies have often tested infants who have a significant family history of autism spectrum disorder, given the increased prevalence observed among such infants. In the present study we tested infants at high- and low-risk for ASD (based on having an older sibling diagnosed with the disorder or not at 6- and 12-months-of-age. We computed intrahemispheric linear coherence between anterior and posterior sites as a measure of neural functional connectivity derived from electroencephalography while the infants were listening to speech sounds. We found that by 12-months-of-age infants at risk for ASD showed reduced functional connectivity compared to low risk infants. Moreover, by 12-months-of-age infants later diagnosed with ASD showed reduced functional connectivity, compared to both infants at low risk for the disorder and infants at high risk who were not later diagnosed with ASD. Significant differences in functional connectivity were also found between low-risk infants and high-risk infants who did not go onto develop ASD. These results demonstrate that reduced functional connectivity appears to be related to genetic vulnerability for ASD. Moreover, they provide further evidence that ASD is broadly characterized by differences in neural integration that emerge during the first year of life.

  15. Feasibility Study of Residential Grid-Connected Solar Photovoltaic Systems in the State of Indiana

    Science.gov (United States)

    Al-Odeh, Mahmoud

    This study aims to measure the financial viability of installing and using a residential grid-connected PV system in the State of Indiana while predicting its performance in eighteen geographical locations within the state over the system's expected lifetime. The null hypothesis of the study is that installing a PV system for a single family residence in the State of Indiana will not pay for itself within 25 years. Using a systematic approach consisting of six steps, data regarding the use of renewable energy in the State of Indiana was collected from the website of the US Department of Energy to perform feasibility analysis of the installation and use of a standard-sized residential PV system. The researcher was not able to reject the null hypothesis that installing a PV system for a single family residence in the State of Indiana will not pay for itself within 25 years. This study found that the standard PV system does not produce a positive project balance and does not pay for itself within 25 years (the life time of the system) assuming the average cost of a system. The government incentive programs are not enough to offset the cost of installing the system against the cost of the electricity that would not be purchased from the utility company. It can be concluded that the cost of solar PV is higher than the market valuation of the power it produces; thus, solar PV did not compete on the cost basis with the traditional competitive energy sources. Reducing the capital cost will make the standard PV system economically viable in Indiana. The study found that the capital cost for the system should be reduced by 15% - 56%.

  16. Impact of in-scanner head motion on multiple measures of functional connectivity: relevance for studies of neurodevelopment in youth.

    Science.gov (United States)

    Satterthwaite, Theodore D; Wolf, Daniel H; Loughead, James; Ruparel, Kosha; Elliott, Mark A; Hakonarson, Hakon; Gur, Ruben C; Gur, Raquel E

    2012-03-01

    It has recently been reported (Van Dijk et al., 2011) that in-scanner head motion can have a substantial impact on MRI measurements of resting-state functional connectivity. This finding may be of particular relevance for studies of neurodevelopment in youth, confounding analyses to the extent that motion and subject age are related. Furthermore, while Van Dijk et al. demonstrated the effect of motion on seed-based connectivity analyses, it is not known how motion impacts other common measures of connectivity. Here we expand on the findings of Van Dijk et al. by examining the effect of motion on multiple types of resting-state connectivity analyses in a large sample of children and adolescents (n=456). Following replication of the effect of motion on seed-based analyses, we examine the influence of motion on graphical measures of network modularity, dual-regression of independent component analysis, as well as the amplitude and fractional amplitude of low frequency fluctuation. In the entire sample, subject age was highly related to motion. Using a subsample where age and motion were unrelated, we demonstrate that motion has marked effects on connectivity in every analysis examined. While subject age was associated with increased within-network connectivity even when motion was accounted for, controlling for motion substantially attenuated the strength of this relationship. The results demonstrate the pervasive influence of motion on multiple types functional connectivity analysis, and underline the importance of accounting for motion in studies of neurodevelopment. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Researching Connection between Service Orientation and Work Satisfaction: A Study of Hotel Employees (Novi Sad, Serbia

    Directory of Open Access Journals (Sweden)

    Marko D. Petrović

    2012-10-01

    Full Text Available In recent years, researches of service industry put in the centre of many papers the phenomena of the relation between service orientation and work (job satisfaction of the employees in the service sector. It have been analyzed many factors that affect the quality of hotel services and opportunities to improve service processes. One of the most important factor of service quality in the hospitality industry is service orientation of employees. On the other side, if the employees are satisfied with the work they are motivated to satisfy customer needs. The purpose of the paper is to study connections and differences among the hotel employees in service orientation and work satisfaction. To determine these issues, we used service orientation scale, developed by Dienhart, Gregoire, Downey and Knight (1992 and work satisfaction scale developed by Lytle (1994. We expected three factor solution for service orientation scale and uni-factor solution for work satisfaction. The results will be discussed and some practical recommendations will be given.

  18. Experiment K-7-29: Connective Tissue Studies. Part 3; Rodent Tissue Repair: Skeletal Muscle

    Science.gov (United States)

    Stauber, W.; Fritz, V. K.; Burkovskaya, T. E.; Ilyina-Kakueva, E. I.

    1994-01-01

    Myofiber injury-repair was studied in the rat gastrocnemius following a crush injury to the lower leg prior to flight in order to understand if the regenerative responses of muscles are altered by the lack of gravitational forces during Cosmos 2044 flight. After 14 days of flight, the gastrocnemius muscle was removed from the 5 injured flight rodents and various Earth-based treatment groups for comparison. The Earth-based animals consisted of three groups of five rats with injured muscles from a simulated, tail-suspended, and vivarium as well as an uninjured basal group. The gastrocnemius muscle from each was evaluated by histochemical and immunohistochemical techniques to document myofiber, vascular, and connective tissue alterations following injury. In general the repair process was somewhat similar in all injured muscle samples with regard to extracellular matrix organization and myofiber regeneration. Small and large myofibers were present with a newly organized extracellular matrix indicative of myogenesis and muscle regeneration. In the tail-suspended animals, a more complete repair was observed with no enlarged area of non-muscle cells or matrix material visible. In contrast, the muscle samples from the flight animals were less well differentiated with more macrophages and blood vessels in the repair region but small myofibers and proteoglycans, nevertheless, were in their usual configuration. Thus, myofiber repair did vary in muscles from the different groups, but for the most part, resulted in functional muscle tissue.

  19. Decreased centrality of subcortical regions during the transition to adolescence: a functional connectivity study.

    Science.gov (United States)

    Sato, João Ricardo; Salum, Giovanni Abrahão; Gadelha, Ary; Vieira, Gilson; Zugman, André; Picon, Felipe Almeida; Pan, Pedro Mario; Hoexter, Marcelo Queiroz; Anés, Mauricio; Moura, Luciana Monteiro; Del'Aquilla, Marco Antonio Gomes; Crossley, Nicolas; Amaro Junior, Edson; Mcguire, Philip; Lacerda, Acioly L T; Rohde, Luis Augusto; Miguel, Euripedes Constantino; Jackowski, Andrea Parolin; Bressan, Rodrigo Affonseca

    2015-01-01

    Investigations of brain maturation processes are a key step to understand the cognitive and emotional changes of adolescence. Although structural imaging findings have delineated clear brain developmental trajectories for typically developing individuals, less is known about the functional changes of this sensitive development period. Developmental changes, such as abstract thought, complex reasoning, and emotional and inhibitory control, have been associated with more prominent cortical control. The aim of this study is to assess brain networks connectivity changes in a large sample of 7- to 15-year-old subjects, testing the hypothesis that cortical regions will present an increasing relevance in commanding the global network. Functional magnetic resonance imaging (fMRI) data were collected in a sample of 447 typically developing children from a Brazilian community sample who were submitted to a resting state acquisition protocol. The fMRI data were used to build a functional weighted graph from which eigenvector centrality (EVC) was extracted. For each brain region (a node of the graph), the age-dependent effect on EVC was statistically tested and the developmental trajectories were estimated using polynomial functions. Our findings show that angular gyrus become more central during this maturation period, while the caudate; cerebellar tonsils, pyramis, thalamus; fusiform, parahippocampal and inferior semilunar lobe become less central. In conclusion, we report a novel finding of an increasing centrality of the angular gyrus during the transition to adolescence, with a decreasing centrality of many subcortical and cerebellar regions.

  20. Attribution of emotions to body postures: an independent component analysis study of functional connectivity in autism.

    Science.gov (United States)

    Libero, Lauren E; Stevens, Carl E; Kana, Rajesh K

    2014-10-01

    The ability to interpret others' body language is a vital skill that helps us infer their thoughts and emotions. However, individuals with autism spectrum disorder (ASD) have been found to have difficulty in understanding the meaning of people's body language, perhaps leading to an overarching deficit in processing emotions. The current fMRI study investigates the functional connectivity underlying emotion and action judgment in the context of processing body language in high-functioning adolescents and young adults with autism, using an independent components analysis (ICA) of the fMRI time series. While there were no reliable group differences in brain activity, the ICA revealed significant involvement of occipital and parietal regions in processing body actions; and inferior frontal gyrus, superior medial prefrontal cortex, and occipital cortex in body expressions of emotions. In a between-group analysis, participants with autism, relative to typical controls, demonstrated significantly reduced temporal coherence in left ventral premotor cortex and right superior parietal lobule while processing emotions. Participants with ASD, on the other hand, showed increased temporal coherence in left fusiform gyrus while inferring emotions from body postures. Finally, a positive predictive relationship was found between empathizing ability and the brain areas underlying emotion processing in ASD participants. These results underscore the differential role of frontal and parietal brain regions in processing emotional body language in autism.

  1. Nail changes in connective tissue diseases: a study of 39 cases

    Science.gov (United States)

    Elmansour, Imane; Chiheb, Soumia; Benchikhi, Hakima

    2014-01-01

    The objective is to identify nail unit changes associated with connective tissue diseases (CTD) and evaluate their frequency. We carried a prospective study between March 2012 and March2013 in our department. All patients with CTD were included. A clinical examination of the fingernails was done by the same dermatologist. Nail features were noted and classified and photos taken. Thirty nine patients were enrolled including: 16 systemic sclerosis, 14 lupus erythematosus (SLE), 8 dermatomyositis (DM), 1 primary Sjorgen's syndrome. The mean age was 40 years old. The mean duration of the disease was 6 years. Nail unit changes were present in 27 patients (69%). The abnormalities observed were Longitidunal ridging in 11 patients, Peri ungueal erythema in 10 patients, Peri-ungual telangiectasia in 11 patients, Ragged cuticle in 10 patients fingertips scars in 9 patients, Increase of longitudinal curvature and beaking of the nail in 4 patients, Increase in transverse curvature in 4 patients, dyschromia of the proximal nail fold in 3 patients, Subungual hyperkeratosis in 3 patients, onycholysis in 2 patients, splinter haemorrhages in 3 patients, nail plate pigmentation in 2 patients, pseudoclubbing in 1 patient, macrolunula in 1 patients, Red lunulae in one patient, bluish- black discoloration of the nail plate in one patient. The proximal nailfold was found to be most sites affected. PMID:25419288

  2. Mapping the connectivity underlying multimodal (verbal and non-verbal) semantic processing: a brain electrostimulation study.

    Science.gov (United States)

    Moritz-Gasser, Sylvie; Herbet, Guillaume; Duffau, Hugues

    2013-08-01

    Accessing the meaning of words, objects, people and facts is a human ability, made possible thanks to semantic processing. Although studies concerning its cortical organization are proficient, the subcortical connectivity underlying this semantic network received less attention. We used intraoperative direct electrostimulation, which mimics a transient virtual lesion during brain surgery for glioma in eight awaken patients, to map the anatomical white matter substrate subserving the semantic system. Patients performed a picture naming task and a non-verbal semantic association test during the electrical mapping. Direct electrostimulation of the inferior fronto-occipital fascicle, a poorly known ventral association pathway which runs throughout the brain, induced in all cases semantic disturbances. These transient disorders were highly reproducible, and concerned verbal as well as non-verbal output. Our results highlight for the first time the essential role of the left inferior fronto-occipital fascicle in multimodal (and not only in verbal) semantic processing. On the basis of these original findings, and in the lights of phylogenetic considerations regarding this fascicle, we suggest its possible implication in the monitoring of the human level of consciousness related to semantic memory, namely noetic consciousness.

  3. Experiment K-7-29: Connective Tissue Studies. Part 3; Rodent Tissue Repair: Skeletal Muscle

    Science.gov (United States)

    Stauber, W.; Fritz, V. K.; Burkovskaya, T. E.; Ilyina-Kakueva, E. I.

    1994-01-01

    Myofiber injury-repair was studied in the rat gastrocnemius following a crush injury to the lower leg prior to flight in order to understand if the regenerative responses of muscles are altered by the lack of gravitational forces during Cosmos 2044 flight. After 14 days of flight, the gastrocnemius muscle was removed from the 5 injured flight rodents and various Earth-based treatment groups for comparison. The Earth-based animals consisted of three groups of five rats with injured muscles from a simulated, tail-suspended, and vivarium as well as an uninjured basal group. The gastrocnemius muscle from each was evaluated by histochemical and immunohistochemical techniques to document myofiber, vascular, and connective tissue alterations following injury. In general the repair process was somewhat similar in all injured muscle samples with regard to extracellular matrix organization and myofiber regeneration. Small and large myofibers were present with a newly organized extracellular matrix indicative of myogenesis and muscle regeneration. In the tail-suspended animals, a more complete repair was observed with no enlarged area of non-muscle cells or matrix material visible. In contrast, the muscle samples from the flight animals were less well differentiated with more macrophages and blood vessels in the repair region but small myofibers and proteoglycans, nevertheless, were in their usual configuration. Thus, myofiber repair did vary in muscles from the different groups, but for the most part, resulted in functional muscle tissue.

  4. Economic and Environmental Study of Wineries Powered by Grid-Connected Photovoltaic Systems in Spain

    Directory of Open Access Journals (Sweden)

    Daniel Gómez-Lorente

    2017-02-01

    Full Text Available This research developed a system that can make factories more independent from the grid. The system enhances efficiency since factory operation is powered by the renewable energy generated during the production process. Winemaking is a key sector that can profit from such a system because wineries can recycle much of the waste from the raw materials employed in wine production. Moreover, the solar energy collected at winemaking facilities can also be used to reduce electricity consumption and thus increase energy efficiency. This study investigated the feasibility of using renewable energy sources, such as solar energy, in wineries in Spain, given the quantity of renewable energy produced in the country. For this purpose, cost-effectiveness, power generation, CO2 emissions and the renewable energy fraction were taken into account. The assumption was that the photovoltaic system was grid-connected. Research results showed a reduction in electrical power costs ranging from 4% to 36%. This reduction was accompanied by an increase in the use of renewable energy of up to 57%. The results obtained are based on self-consumption or net metering policy as well as the production capacity of the winery.

  5. Nail changes in connective tissue diseases: a study of 39 cases.

    Science.gov (United States)

    Elmansour, Imane; Chiheb, Soumia; Benchikhi, Hakima

    2014-01-01

    The objective is to identify nail unit changes associated with connective tissue diseases (CTD) and evaluate their frequency. We carried a prospective study between March 2012 and March2013 in our department. All patients with CTD were included. A clinical examination of the fingernails was done by the same dermatologist. Nail features were noted and classified and photos taken. Thirty nine patients were enrolled including: 16 systemic sclerosis, 14 lupus erythematosus (SLE), 8 dermatomyositis (DM), 1 primary Sjorgen's syndrome. The mean age was 40 years old. The mean duration of the disease was 6 years. Nail unit changes were present in 27 patients (69%). The abnormalities observed were Longitidunal ridging in 11 patients, Peri ungueal erythema in 10 patients, Peri-ungual telangiectasia in 11 patients, Ragged cuticle in 10 patients fingertips scars in 9 patients, Increase of longitudinal curvature and beaking of the nail in 4 patients, Increase in transverse curvature in 4 patients, dyschromia of the proximal nail fold in 3 patients, Subungual hyperkeratosis in 3 patients, onycholysis in 2 patients, splinter haemorrhages in 3 patients, nail plate pigmentation in 2 patients, pseudoclubbing in 1 patient, macrolunula in 1 patients, Red lunulae in one patient, bluish-black discoloration of the nail plate in one patient. The proximal nailfold was found to be most sites affected.

  6. A study and development of Windows based program of reliability analysis for assessing service life of cracked connections

    Directory of Open Access Journals (Sweden)

    Suchart Limkatanyu

    2006-09-01

    Full Text Available The development of a Windows based framework to undertake probabilistic fracture mechanics studies is reported. The reliability method used in the program is Monte-Carlo Simulation method. The results of the computation of the program are stress intensity factor, reliability index and probability of failure. The probabilistic studies of cruciform welded joint containing Lack of Penetration (LOP defect and T-butt geometry containing surface crack at weld toe are performed in both critical crack growth and fatigue problem. The results can be used as an indicator for assuring the safety of this particular type of connection. It can also be used as a design criterion for the connection.

  7. Task-related functional connectivity in autism spectrum conditions: an EEG study using wavelet transform coherence

    Directory of Open Access Journals (Sweden)

    Catarino Ana

    2013-01-01

    Full Text Available Abstract Background Autism Spectrum Conditions (ASC are a set of pervasive neurodevelopmental conditions characterized by a wide range of lifelong signs and symptoms. Recent explanatory models of autism propose abnormal neural connectivity and are supported by studies showing decreased interhemispheric coherence in individuals with ASC. The first aim of this study was to test the hypothesis of reduced interhemispheric coherence in ASC, and secondly to investigate specific effects of task performance on interhemispheric coherence in ASC. Methods We analyzed electroencephalography (EEG data from 15 participants with ASC and 15 typical controls, using Wavelet Transform Coherence (WTC to calculate interhemispheric coherence during face and chair matching tasks, for EEG frequencies from 5 to 40 Hz and during the first 400 ms post-stimulus onset. Results Results demonstrate a reduction of interhemispheric coherence in the ASC group, relative to the control group, in both tasks and for all electrode pairs studied. For both tasks, group differences were generally observed after around 150 ms and at frequencies lower than 13 Hz. Regarding within-group task comparisons, while the control group presented differences in interhemispheric coherence between faces and chairs tasks at various electrode pairs (FT7-FT8, TP7-TP8, P7-P8, such differences were only seen for one electrode pair in the ASC group (T7-T8. No significant differences in EEG power spectra were observed between groups. Conclusions Interhemispheric coherence is reduced in people with ASC, in a time and frequency specific manner, during visual perception and categorization of both social and inanimate stimuli and this reduction in coherence is widely dispersed across the brain. Results of within-group task comparisons may reflect an impairment in task differentiation in people with ASC relative to typically developing individuals. Overall, the results of this research support the value of WTC

  8. The brain network reflecting bodily self-consciousness: a functional connectivity study.

    Science.gov (United States)

    Ionta, Silvio; Martuzzi, Roberto; Salomon, Roy; Blanke, Olaf

    2014-12-01

    Several brain regions are important for processing self-location and first-person perspective, two important aspects of bodily self-consciousness. However, the interplay between these regions has not been clarified. In addition, while self-location and first-person perspective in healthy subjects are associated with bilateral activity in temporoparietal junction (TPJ), disturbed self-location and first-person perspective result from damage of only the right TPJ. Identifying the involved brain network and understanding the role of hemispheric specializations in encoding self-location and first-person perspective, will provide important information on system-level interactions neurally mediating bodily self-consciousness. Here, we used functional connectivity and showed that right and left TPJ are bilaterally connected to supplementary motor area, ventral premotor cortex, insula, intraparietal sulcus and occipitotemporal cortex. Furthermore, the functional connectivity between right TPJ and right insula had the highest selectivity for changes in self-location and first-person perspective. Finally, functional connectivity revealed hemispheric differences showing that self-location and first-person perspective modulated the connectivity between right TPJ, right posterior insula, and right supplementary motor area, and between left TPJ and right anterior insula. The present data extend previous evidence on healthy populations and clinical observations in neurological deficits, supporting a bilateral, but right-hemispheric dominant, network for bodily self-consciousness.

  9. Simulating urban growth by emphasis on connective routes network (case study: Bojnourd city

    Directory of Open Access Journals (Sweden)

    Mehdi Saadat Novin

    2017-06-01

    Full Text Available Development of urban construction and ever-increasing growth of population lead to landuse changes especially in agricultural lands, which play an important role in providing human food. According to this issue, a proper landuse planning is required to protecting and preserving the valuable agricultural lands and environment, in today’s world. The prediction of urban growth can help in understanding the potential impacts on a region’s water resource, economy and people. One of the effective parameters in development of cities is connective routes network and their different types and qualities that play an important role in decreasing or increasing the growth of the city. On the other hand, the type of the connective routes network is an important factor for the speed and quality of development. In this paper, two different scenarios were used to simulate landuse changes and analyzing their results. In first scenario, modeling is based on the effective parameters in urban growth without classification of connective routes network. In the second scenario, effective parameters in urban growth were considered and connective routes were classified in 6 different classes with different weights in order to examine their effect on urban development. Simulation of landuse has been carried out for 2020–2050. The results clearly showed the effect of the connective routes network classification in output maps so that the effect of the first and second main routes network in development, is conspicuous.

  10. Subcutaneous Connective Tissue Reactions to Various Endodontic Biomaterials: An Animal Study

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Saghiri

    2013-03-01

    Full Text Available Background and aims. Biocompatibility of root-end filling materials is a matter of debate. The aim of this study was to compare the biocompatibility of a variety of commercial ProRoot WMTA cements and a resin-based cement (Geristore® with different pH values of setting reaction and different aluminum contents, implanted into the subcutaneous connective tissue of rats at various time intervals. Materials and methods. Fifty Sprague-Dawley rats were used in this study. Polyethylene tubes were filled with Angelus WMTA, ProRoot WMTA, Bioaggregate, and Geristore. Empty control tubes were implanted into subcutaneous tissues and harvested at 7-, 14-, 28- and 60-day intervals. Tissue sections of 5 μm were stained with hematoxylin and eosin and observed under a light microscope. Inflammatory reactions were categorized as 0, none (without inflammatory cells; 1, mild (inflammatory cells ≤25; 2, moderate (25–125 inflammatory cells; and 3, severe (>125 inflammatory cells. Statistical analysis was performed with Kruskal-Wallis and Mann Whitney U tests. Results. ProRoot WMTA and Angelus elicited significantly less inflammation than other materials (P<0.05. After 7 days, however, all the materials induced significantly more inflammation than the controls (P<0.05. Angelus-MTA group exhibited no significant differences from the Bioaggregate group (P=0.15; however, ProRoot WMTA elicited significantly less inflammation than Bioaggregate (P=0.02. Geristore induced significantly more inflammation than other groups (P<0.05. Conclusion. Geristore induced an inflammatory response higher than ProRoot WMTA; therefore, it is not recommended for clinical use.

  11. Subcutaneous Connective Tissue Reactions to Various Endodontic Biomaterials: An Animal Study

    Science.gov (United States)

    Saghiri, Mohammad Ali; Tanideh, Nader; Garcia-Godoy, Franklin; Lotfi, Mehrdad; Karamifar, Kasra; Amanat, Dariush

    2013-01-01

    Background and aims Biocompatibility of root-end filling materials is a matter of debate. The aim of this study was to compare the biocompatibility of a variety of commercial ProRoot WMTA cements and a resin-based cement (Geristore®) with different pH values of setting reaction and different aluminum contents, implanted into the subcutaneous connective tissue of rats at various time intervals. Materials and methods Fifty Sprague-Dawley rats were used in this study. Polyethylene tubes were filled with Angelus WMTA, ProRoot WMTA, Bioaggregate, and Geristore. Empty control tubes were implanted into subcutaneous tissues and harvested at 7-, 14-, 28- and 60-day intervals. Tissue sections of 5 μm were stained with hematoxylin and eosin and observed under a light microscope. Inflammatory reactions were categorized as 0, none (without inflammatory cells); 1, mild (inflammatory cells ≤25); 2, moderate (25–125 inflammatory cells); and 3, severe (>125 inflammatory cells). Statistical analysis was performed with Kruskal-Wallis and Mann Whitney U tests. Results ProRoot WMTA and Angelus elicited significantly less inflammation than other materials (P<0.05). After 7 days, however, all the materials induced significantly more inflammation than the controls (P<0.05). Angelus-MTA group exhi-bited no significant differences from the Bioaggregate group (P=0.15); however, ProRoot WMTA elicited significantly less inflammation than Bioaggregate (P=0.02). Geristore induced significantly more inflammation than other groups (P<0.05). Conclusion Geristore induced an inflammatory response higher than ProRoot WMTA; therefore, it is not recommended for clinical use. PMID:23486841

  12. Depletion of brain functional connectivity enhancement leads to disability progression in multiple sclerosis: A longitudinal resting-state fMRI study.

    Science.gov (United States)

    Faivre, Anthony; Robinet, Emmanuelle; Guye, Maxime; Rousseau, Celia; Maarouf, Adil; Le Troter, Arnaud; Zaaraoui, Wafaa; Rico, Audrey; Crespy, Lydie; Soulier, Elisabeth; Confort-Gouny, Sylviane; Pelletier, Jean; Achard, Sophie; Ranjeva, Jean-Philippe; Audoin, Bertrand

    2016-11-01

    The compensatory effect of brain functional connectivity enhancement in relapsing-remitting multiple sclerosis (RRMS) remains controversial. To characterize the relationships between brain functional connectivity changes and disability progression in RRMS. Long-range connectivity, short-range connectivity, and density of connections were assessed using graph theoretical analysis of resting-state functional magnetic resonance imaging (fMRI) data acquired in 38 RRMS patients (disease duration: 120 ± 32 months) and 24 controls. All subjects were explored at baseline and all patients and six controls 2 years later. At baseline, levels of long-range and short-range brain functional connectivity were higher in patients compared to controls. During the follow-up, decrease in connections' density was inversely correlated with disability progression. Post-hoc analysis evidenced differential evolution of brain functional connectivity metrics in patients according to their level of disability at baseline: while patients with lowest disability at baseline experienced an increase in all connectivity metrics during the follow-up, patients with higher disability at baseline showed a decrease in the connectivity metrics. In these patients, decrease in the connectivity metrics was associated with disability progression. The study provides two main findings: (1) brain functional connectivity enhancement decreases during the disease course after reaching a maximal level, and (2) decrease in brain functional connectivity enhancement participates in disability progression. © The Author(s), 2016.

  13. Study on Battery Capacity for Grid-connection Power Planning with Forecasts in Clustered Photovoltaic Systems

    Science.gov (United States)

    Shimada, Takae; Kawasaki, Norihiro; Ueda, Yuzuru; Sugihara, Hiroyuki; Kurokawa, Kosuke

    This paper aims to clarify the battery capacity required by a residential area with densely grid-connected photovoltaic (PV) systems. This paper proposes a planning method of tomorrow's grid-connection power from/to the external electric power system by using demand power forecasting and insolation forecasting for PV power predictions, and defines a operation method of the electricity storage device to control the grid-connection power as planned. A residential area consisting of 389 houses consuming 2390 MWh/year of electricity with 2390kW PV systems is simulated based on measured data and actual forecasts. The simulation results show that 8.3MWh of battery capacity is required in the conditions of half-hour planning and 1% or less of planning error ratio and PV output limiting loss ratio. The results also show that existing technologies of forecasting reduce required battery capacity to 49%, and increase the allowable installing PV amount to 210%.

  14. Altered Functional Connectivity in Essential Tremor: A Resting-State fMRI Study.

    Science.gov (United States)

    Benito-León, Julián; Louis, Elan D; Romero, Juan Pablo; Hernández-Tamames, Juan Antonio; Manzanedo, Eva; Álvarez-Linera, Juan; Bermejo-Pareja, Félix; Posada, Ignacio; Rocon, Eduardo

    2015-12-01

    Essential tremor (ET) has been associated with a spectrum of clinical features, with both motor and nonmotor elements, including cognitive deficits. We employed resting-state functional magnetic resonance imaging (fMRI) to assess whether brain networks that might be involved in the pathogenesis of nonmotor manifestations associated with ET are altered, and the relationship between abnormal connectivity and ET severity and neuropsychological function.Resting-state fMRI data in 23 ET patients (12 women and 11 men) and 22 healthy controls (HC) (12 women and 10 men) were analyzed using independent component analysis, in combination with a "dual-regression" technique, to identify the group differences of resting-state networks (RSNs) (default mode network [DMN] and executive, frontoparietal, sensorimotor, cerebellar, auditory/language, and visual networks). All participants underwent a neuropsychological and neuroimaging session, where resting-state data were collected.Relative to HC, ET patients showed increased connectivity in RSNs involved in cognitive processes (DMN and frontoparietal networks) and decreased connectivity in the cerebellum and visual networks. Changes in network integrity were associated not only with ET severity (DMN) and ET duration (DMN and left frontoparietal network), but also with cognitive ability. Moreover, in at least 3 networks (DMN and frontoparietal networks), increased connectivity was associated with worse performance on different cognitive domains (attention, executive function, visuospatial ability, verbal memory, visual memory, and language) and depressive symptoms. Further, in the visual network, decreased connectivity was associated with worse performance on visuospatial ability.ET was associated with abnormal brain connectivity in major RSNs that might be involved in both motor and nonmotor symptoms. Our findings underscore the importance of examining RSNs in this population as a biomarker of disease.

  15. Altered interhemispheric functional connectivity in patients with anisometropic and strabismic amblyopia: a resting-state fMRI study

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Minglong; Xie, Bing; Yin, Xuntao; Wang, Jian [Third Military Medical University, Department of Radiology, Southwest Hospital, 30 Gaotanyan Street, Shapingba District, Chongqing (China); Yang, Hong; Wang, Hao [Third Military Medical University, Ophthalmology Research Center, Southwest Eye Hospital/Southwest Hospital, Chongqing (China); Yu, Longhua [Third Military Medical University, Department of Radiology, Southwest Hospital, 30 Gaotanyan Street, Shapingba District, Chongqing (China); 401st Hospital of PLA, Department of Radiology, Qingdao (China); He, Sheng [University of Minnesota Twin Cities, Department of Psychology, Minneapolis, MN (United States)

    2017-05-15

    Altered brain functional connectivity has been reported in patients with amblyopia by recent neuroimaging studies. However, relatively little is known about the alterations in interhemispheric functional connectivity in amblyopia. The present study aimed to investigate the functional connectivity patterns between homotopic regions across hemispheres in patients with anisometropic and strabismic amblyopia under resting state. Nineteen monocular anisometropic amblyopia (AA), 18 strabismic amblyopia (SA), and 20 normal-sight controls (NC) were enrolled in this study. After a comprehensive ophthalmologic examination, resting-state fMRI scanning was performed in all participants. The pattern of the interhemispheric functional connectivity was measured with the voxel-mirrored homotopic connectivity (VMHC) approach. VMHC values differences within and between three groups were compared, and correlations between VMHC values and each the clinical variable were also analyzed. Altered VMHC was observed in AA and SA patients in lingual gyrus and fusiform gyrus compared with NC subjects. The altered VMHC of lingual gyrus showed a pattern of AA > SA > NC, while the altered VMHC of fusiform gyrus showed a pattern of AA > NC > SA. Moreover, the VMHC values of lingual gyrus were positively correlated with the stereoacuity both in AA and SA patients, and the VMHC values of fusiform gyrus were positively correlated with the amount of anisometropia just in AA patients. These findings suggest that interhemispheric functional coordination between several homotopic visual-related brain regions is impaired both in AA and SA patients under resting state and revealed the similarities and differences in interhemispheric functional connectivity between the anisometropic and strabismic amblyopia. (orig.)

  16. Functional connectivity between parietal and frontal brain regions and intelligence in young children: the Generation R study.

    Science.gov (United States)

    Langeslag, Sandra J E; Schmidt, Marcus; Ghassabian, Akhgar; Jaddoe, Vincent W; Hofman, Albert; van der Lugt, Aad; Verhulst, Frank C; Tiemeier, Henning; White, Tonya J H

    2013-12-01

    It has been shown in adults that individual differences in intelligence are related to the integrity of the interaction between parietal and frontal brain regions. Since connectivity between distant brain regions strengthens during childhood, it is unclear when in the course of development this relationship emerges. Thus, the goal of this study was to determine whether parietal-frontal functional connectivity is associated with intelligence in young children. We performed independent component analyses on resting-state fMRI data of 115 children (6-8 years old) to select seed and target regions for a seed/target region correlation analysis. We found that higher nonverbal intelligence was associated with increased functional connectivity between right parietal and right frontal regions, and between right parietal and dorsal anterior cingulate regions. The association between intelligence and functional connectivity between certain brain regions was stronger in girls than boys. In conclusion, we found that connectivity between the parietal and frontal lobes is critically involved in intelligence in young children. Copyright © 2012 Wiley Periodicals, Inc.

  17. Study of 18-Pulse Rectifier Utilizing Hexagon Connected 3-Phase to 9-Phase Transformer

    Directory of Open Access Journals (Sweden)

    Ahmad Saudi Samosir

    2008-04-01

    Full Text Available The 18-pulse converter, using Y or -connected differential autotransformer, is very interesting since it allows natural high power factor correction. The lowest input current harmonic components are the 17th and 19th. The Transformer is designed to feed three six-pulse bridge rectifiers displaced in phase by 200. This paper present a high power factor three-phase rectifier bases on 3-phase to 9-phase transformer and 18-pulse rectifier. The 9-phase polygon-connected transformer followed by 18-pulse diode rectifiers ensures the fundamental concept of natural power factor correction. Simulation results to verify the proposed concept are shown in this paper.

  18. Improved wire stiffness with modified connection bolts in Ilizarov external frames: a biomechanical study.

    Science.gov (United States)

    Gessmann, Jan; Jettkant, Birger; Königshausen, Matthias; Schildhauer, Thomas Armin; Seybold, Dominik

    2012-01-01

    Frame stability in Ilizarov external fixators is mainly dependent on the tension of the transosseous wires, which are clamped to the ring by connection bolts. It was the purpose of this biomechanical study to investigate the holding capacity of a modified bolt design featuring a ruffled wire-bolt interface (TrueLok™) and its influence on wire stiffness in comparison with that of classic bolts featuring a smooth, unruffled wire-bolt interface. Six different ring and bolt configurations were tested using a simplified model consisting of a single ring and wire. The holding capacity at two different tightening torques (10 and 14 Nm) of classic cannulated bolts (CB) and slotted bolts (SB) was determined on Ilizarov and Taylor Spatial Frame (TSF™) rings, whereas the modified TrueLok™ CBs and SBs were used with the TrueLok™ rings. The wire stiffness was calculated via a regression analysis of the load-displacement graphs. The modified TrueLok™ bolts demonstrated significantly better slippage resistance than the classic bolts in all configurations and wire stiffness was significantly higher in the TrueLok™ frame set-ups. After maximum loading, all of the wires showed plastic deformation, including constant wire deflection and dent marks at the clamped wire ends. In conclusion, the decrease in wire stiffness can be explained mainly as a result of wire slippage, but plastic deformation and material yielding also contribute. The relatively simple modification made by roughening the wire-bolt interface results in improved holding capacity and wire stiffness. A frame that contains these modified TrueLok™ bolts should provide improved mechanical stiffness.

  19. Fragmentation and connection of frames in collaborative water governance: a case study of river catchment management in Southern Ecuador

    NARCIS (Netherlands)

    Dewulf, A.; Mancero, M.; Cárdenas, G.; Sucozhañay, D.

    2011-01-01

    In collaborative water governance, the variety of frames that actors bring to the discussion constitutes an important challenge. In this study, we analyse the fragmentation and connection of frames in collaborative water governance projects in the Paute catchment and its sub-catchment Tabacay in the

  20. Economy, Work, and Education: Critical Connections. Routledge Advances in Management and Business Studies

    Science.gov (United States)

    Casey, Catherine

    2011-01-01

    "Economy, Work and Education: Critical Connections" addresses effects of neoliberal capitalism in particular regard to work and education. The book elaborates key aspects and problems of generalized policy models of knowledge-based economies and learning societies in contexts of liberalized firm action, accelerated competitiveness and labor market…

  1. Economy, Work, and Education: Critical Connections. Routledge Advances in Management and Business Studies

    Science.gov (United States)

    Casey, Catherine

    2011-01-01

    "Economy, Work and Education: Critical Connections" addresses effects of neoliberal capitalism in particular regard to work and education. The book elaborates key aspects and problems of generalized policy models of knowledge-based economies and learning societies in contexts of liberalized firm action, accelerated competitiveness and labor market…

  2. Connecting between School and Work: A Case Study in Customer Relations.

    Science.gov (United States)

    Hohberg, Tonian J.

    1985-01-01

    This article shares some of the strategies and activities that the author believes will improve the connections between independent career education and the world of work. These activities concern school business cooperation, student motivation, student involvement, staff involvement, community and government relations, and career planning and…

  3. Posterior cingulated cortex functional connectivity in deficit schizophrenia: a resting state functional magnetic resonance imaging study

    Institute of Scientific and Technical Information of China (English)

    唐小伟

    2014-01-01

    Objective To explore the discrepancies of the network of resting brain functional connectivity related to posterior cingulated cortex(PCC)between deficit schizophrenia patients and normal control.Methods Thirty male patients of deficit schizophrenia,nondeficit schizophrenia and 30 healthy controls were enrolled,and the age,education level and sex were matched between three

  4. Soil erosion and sediment connectivity modelling in Burgundy vineyards: case study of Mercurey, France

    Science.gov (United States)

    Fressard, Mathieu; Cossart, Étienne; Lejot, Jêrome; Michel, Kristell; Perret, Franck; Christol, Aurélien; Mathian, Hélène; Navratil, Oldrich

    2017-04-01

    This research aims at assessing the impact of agricultural landscape structure on soil erosion and sediment connectivity at the catchment scale. The investigations were conducted the vineyards of Mercurey (Burgundy, France), characterized by important issues related to soil loss, flash floods and associated management infrastructures maintenance. The methodology is based on two main steps that include (1) field investigations and (2) modelling. The field investigations consists in DEM acquisition by LiDAR imaging from a drone, soil mapping and human infrastructures impacting runoff classification and mapping (such as crop rows, storm water-basins, drainage network, roads, etc.). These data aims at supplying the models with field observations. The modelling strategy is based on two main steps: First, the modelling of soil sensitivity to erosion, using the spatial application of the RUSLE equation. Secondly, to assess the sediment connectivity in this area, a model based on graph theory developed by Cossart and Fressard (2017) is tested. The results allow defining the influence of different anthropogenic structures on the sediment connectivity and soil erosion at the basin scale. A set of sub-basins influenced by various anthropogenic infrastructures have been identified and show contrasted sensitivities to erosion. The modelling of sediment connectivity show that the runoff pattern is strongly influenced by the vine rows orientation and the drainage network. I has also permitted to identify non collected (by storm water-basins) areas that strongly contribute to the turbid floods sediment supply and to soil loss during high intensity precipitations events.

  5. Harmonic Stability Studies in VSC-HVDC Grid Connected Offshore Wind Power Plants

    DEFF Research Database (Denmark)

    Glasdam, Jakob Bærholm; Gevorgian, Vahan; Bak, Claus Leth

    2017-01-01

    the harmonic instability phenomena in HVDC grid connected OWPPs using both frequency and time domain simulations. A good correlation at lower frequencies between the two domains is observed. However, the frequency domain is insufficient at higher frequencies (i.e. in the vicinity of the switching frequency...

  6. Increased Alpha Band Functional Connectivity Following the Quadrato Motor Training: A Longitudinal Study

    Directory of Open Access Journals (Sweden)

    Stefano Lasaponara

    2017-06-01

    Full Text Available Quadrato Motor Training (QMT is a new training paradigm, which was found to increase cognitive flexibility, creativity and spatial cognition. In addition, QMT was reported to enhance inter- and intra-hemispheric alpha coherence as well as Fractional Anisotropy (FA in a number of white matter pathways including corpus callosum. Taken together, these results seem to suggest that electrophysiological and structural changes induced by QMT may be due to an enhanced interplay and communication of the different brain areas within and between the right and the left hemisphere. In order to test this hypothesis using the exact low-resolution brain electromagnetic tomography (eLORETA, we estimated the current neural density and lagged linear connectivity (LLC of the alpha band in the resting state electroencephalography (rsEEG recorded with open (OE and closed eyes (CE at three different time points, following 6 and 12 weeks of daily QMT. Significant changes were observed for the functional connectivity. In particular, we found that limbic and fronto-temporal alpha connectivity in the OE condition increased after 6 weeks, while it enhanced at the CE condition in occipital network following 12-weeks of daily training. These findings seem to show that the QMT may have dissociable long-term effects on the functional connectivity depending on the different ways of recording rsEEG. OE recording pointed out a faster onset of Linear Lag Connectivity modulations that tend to decay as quickly, while CE recording showed sensible effect only after the complete 3-months training.

  7. Altered activity and functional connectivity of superior temporal gyri in anxiety disorders: A functional magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiaohu; Xi, Qian; Wang, Peijun; Li, Chunbo [Tong Ji Hospital of Tong Ji University, Shanghai (China); He, Hongjian [Bio-X lab, Dept. of Physics, Zhe Jiang University, Hangzhou (China)

    2014-08-15

    The prior functional MRI studies have demonstrated significantly abnormal activity in the bilateral superior temporal gyrus (STG) of anxiety patients. The purpose of the current investigation was to determine whether the abnormal activity in these regions was related to a loss of functional connectivity between these regions. Ten healthy controls and 10 anxiety patients underwent noninvasive fMRI while actively listening to emotionally neutral words alternated by silence (Task 1) or threat-related words (Task 2). The participants were instructed to silently make a judgment of each word's valence (i.e., unpleasant, pleasant, or neutral). A coherence analysis was applied to the functional MRI data to examine the functional connectivity between the left and the right STG, which was selected as the primary region of interest on the basis of our prior results. The data demonstrated that the anxiety patients exhibited significantly increased activation in the bilateral STG than the normal controls. The functional connectivity analysis indicated that the patient group showed significantly decreased degree of connectivity between the bilateral STG during processing Task 2 compared to Task 1 (t = 2.588, p = 0.029). In addition, a significantly decreased connectivity was also observed in the patient group compared to the control group during processing Task 2 (t = 2.810, p = 0.012). Anxiety patients may exhibit increased activity of the STG but decreased functional connectivity between the left and right STG, which may reflect the underlying neural abnormality of anxiety disorder, and this will provide new insights into this disease.

  8. Subcallosal Cingulate Connectivity in Anorexia Nervosa Patients Differs From Healthy Controls: A Multi-tensor Tractography Study.

    Science.gov (United States)

    Hayes, Dave J; Lipsman, Nir; Chen, David Q; Woodside, D Blake; Davis, Karen D; Lozano, Andres M; Hodaie, Mojgan

    2015-01-01

    Anorexia nervosa is characterized by extreme low body weight and alterations in affective processing. The subcallosal cingulate regulates affect through wide-spread white matter connections and is implicated in the pathophysiology of anorexia nervosa. We examined whether those with treatment refractory anorexia nervosa undergoing deep brain stimulation (DBS) of the subcallosal white matter (SCC) show: (1) altered anatomical SCC connectivity compared to healthy controls, (2) white matter microstructural changes, and (3) microstructural changes associated with clinically-measured affect. Diffusion magnetic resonance imaging (dMRI) and deterministic multi-tensor tractography were used to compare anatomical connectivity and microstructure in SCC-associated white matter tracts. Eight women with treatment-refractory anorexia nervosa were compared to 8 age- and sex-matched healthy controls. Anorexia nervosa patients also completed affect-related clinical assessments presurgically and 12 months post-surgery. (1) Higher (e.g., left parieto-occipital cortices) and lower (e.g., thalamus) connectivity in those with anorexia nervosa compared to controls. (2) Decreases in fractional anisotropy, and alterations in axial and radial diffusivities, in the left fornix crus, anterior limb of the internal capsule (ALIC), right anterior cingulum and left inferior fronto-occipital fasciculus. (3) Correlations between dMRI metrics and clinical assessments, such as low pre-surgical left fornix and right ALIC fractional anisotropy being related to post-DBS improvements in quality-of-life and depressive symptoms, respectively. We identified widely-distributed differences in SCC connectivity in anorexia nervosa patients consistent with heterogenous clinical disruptions, although these results should be considered with caution given the low number of subjects. Future studies should further explore the use of affect-related connectivity and behavioral assessments to assist with DBS target

  9. Connecting the solubility and CCN activation of complex organic aerosols: a theoretical study using solubility distributions

    Science.gov (United States)

    Riipinen, I.; Rastak, N.; Pandis, S. N.

    2015-06-01

    We present a theoretical study investigating the cloud activation of multicomponent organic particles. We modeled these complex mixtures using solubility distributions (analogous to volatility distributions in the VBS, i.e., volatility basis set, approach), describing the mixture as a set of surrogate compounds with varying water solubilities in a given range. We conducted Köhler theory calculations for 144 different mixtures with varying solubility range, number of components, assumption about the organic mixture thermodynamics and the shape of the solubility distribution, yielding approximately 6000 unique cloud condensation nucleus (CCN)-activation points. The results from these comprehensive calculations were compared to three simplifying assumptions about organic aerosol solubility: (1) complete dissolution at the point of activation; (2) combining the aerosol solubility with the molar mass and density into a single effective hygroscopicity parameter κ; and (3) assuming a fixed water-soluble fraction ϵeff. The complete dissolution was able to reproduce the activation points with a reasonable accuracy only when the majority (70-80%) of the material was dissolved at the point of activation. The single-parameter representations of complex mixture solubility were confirmed to be powerful semi-empirical tools for representing the CCN activation of organic aerosol, predicting the activation diameter within 10% in most of the studied supersaturations. Depending mostly on the condensed-phase interactions between the organic molecules, material with solubilities larger than about 0.1-100 g L-1 could be treated as soluble in the CCN activation process over atmospherically relevant particle dry diameters and supersaturations. Our results indicate that understanding the details of the solubility distribution in the range of 0.1-100 g L-1 is thus critical for capturing the CCN activation, while resolution outside this solubility range will probably not add

  10. A Qualitative Case Study of Smartphone-Connected Hearing Aids: Influences on Patients, Clinicians, and Patient-Clinician Interactions.

    Science.gov (United States)

    Ng, Stella L; Phelan, Shanon; Leonard, MaryAnn; Galster, Jason

    2017-06-01

    Innovations in hearing aid technology influence clinicians and individuals who use hearing aids. Little research, to date, explains the innovation adoption experiences and perspectives of clinicians and patients, which matter to a field like audiology, wherein technology innovation is constant. By understanding clinician and patient experiences with such innovations, the field of audiology may develop technologies and ways of practicing in a manner more responsive to patients' needs, and attentive to society's influence. The authors aimed to understand how new innovations influence clinician and patient experiences, through a study focusing on connected hearing aids. "Connected" refers to the wireless functional connection of hearing aids with everyday technologies like mobile phones and tablets. The authors used a qualitative collective case study methodology, borrowing from constructivist grounded theory for data collection and analysis methods. Specifically, the authors designed a collective case study of a connected hearing aid and smartphone application, composed of two cases of experience with the innovation: the case of clinician experiences, and the case of patient experiences. The qualitative sampling methods employed were case sampling, purposive within-case sampling, and theoretical sampling, and culminated in a total collective case n = 19 (clinician case n = 8; patient case n = 11). These data were triangulated with a supplementary sample of ten documents: relevant news and popular media collected during the study time frame. The authors conducted interviews with the patients and clinicians, and analyzed the interview and document data using the constant comparative method. The authors compared their two cases by looking at trends within, between, and across cases. The clinician case highlighted clinicians' heuristic-based candidacy judgments in response to the adoption of the connected hearing aids into their practice. The patient case revealed

  11. Hierarchical mechanics of connective tissues: integrating insights from nano to macroscopic studies.

    Science.gov (United States)

    Gohl, Kheng Lim; Listrat, Anne; Béchet, Daniel

    2014-10-01

    As the key component of the musculoskeletal system, the extracellular matrix of soft connective tissues such as ligaments and tendons is a biological example of fibre-reinforced composite but with a complex hierarchical architecture. To establish a comprehensive structure-function relationship at the respective levels (i.e., from molecule to tissue) of the hierarchical architecture is challenging and requires a multidisciplinary approach, involving the integration of findings from the fields of molecular biology, biochemistry, structural biology, materials science and biophysics. Accordingly, in recent years, some of these fields, namely structural biology, materials science and biophysics, have made significant progress in the microscale and nanoscale studies of extracellular matrix using new tools, such as microelectromechanical systems, optical tweezers and atomic force microscopy, complemented by new techniques in simultaneous imaging and mechanical testing and computer modelling. The intent of this paper is to review the key findings on the mechanical response of extracellular matrix at the respective levels of the hierarchical architecture. The main focus is on the structure and function--the findings are compared across the different levels to provide insights that support the goal of establishing a comprehensive structure-function relationship of extracellular matrix. For this purpose, the review is divided into two parts. The first part explores the features of key structural units of extracellular matrix, namely tropocollagen molecule (the lowest level), microfibril, collagen fibril, collagen fibre and fascicle. The second part examines the mechanics of the structural units at the respective levels. Finally a framework for extracellular matrix mechanics is proposed to support the goal to establish a comprehensive structure-function relationship. The framework describes the integration of the mechanisms of reinforcement by the structural units at the

  12. Efficiency study of different photovoltaic plant connection schemes under dynamic shading

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Reinoso, C.R.; Milone, D.H. [Centro de Investigacion y Desarrollo en Senales, Sistemas e Inteligencia Computacional (SINC), Facultad de Ing. y Ciencias Hidricas UNL-CONICET, Ciudad Universitaria (3000) Santa Fe (Argentina); Buitrago, R.H. [Instituto de Desarrollo Tecnologico para la Industria Quimica (INTEC) UNL-CONICET, Guemes 3450 (3000) Santa Fe (Argentina)

    2010-06-15

    An important growth in the power of the photovoltaic systems connected to a grid has recently been observed. In spite of the advances in module technology, the problems in the system design increased, especially regarding the surface of the earth they occupy. In this work we propose a complete model for plant simulation with different wiring diagrams and under dynamic shading. Results obtained from simulations showed that the configuration with the lowest performance was that of only one serial-parallel group, whereas the highest efficiency corresponded to a design of groups of modules in parallel connected then in series. In general, a higher efficiency was obtained diminishing the quantity of modules in series and increasing their number in parallel. The simulation model proposed allows exploring different alternatives of wiring modules and finding the most efficient configurations for photovoltaic plants of medium and high power. (author)

  13. Modeling and Experimental Study on Grid-Connected Inverter for Direct Drive Wind Turbine

    Directory of Open Access Journals (Sweden)

    HUANG Wang-jun

    2013-04-01

    Full Text Available This paper designs a dual topological structure of grid-connected inverter for high-power wind turbine, introduces PWM converter's operational state, and establishes its mathematical model, then it puts forward the dual closed-loop vector control strategy of grid-side converter based on dq coordinate. The combination of the dual topological structure and decoupling control realizes the functioning of high-power factor and two-way transmission of energy. Grid-side converter can stabilize DC side voltage and adjust active or reactive output current independently when wind velocity changes rapidly, which leads to the change of output power in generator. The hardware experiment and simulation results verify the feasibility of the proposed control scheme in both the high stability accuracy and excellent property of grid-connection.

  14. Study of sandwiched three-port transmission grating with a connection layer under normal incidence

    Science.gov (United States)

    Li, Hongtao; Wang, Bo

    2016-09-01

    A sandwiched three-port transmission grating with a connection layer under normal incidence is shown. The sandwiched dielectric grating can mainly diffract the identical energies in the ±1st orders and the zeroth diffraction order based on optimized grating parameters by employing rigorous coupled-wave analysis (RCWA) for TE and TM polarizations. On account of optimized parameters, efficiencies more than 32.5% in each diffraction order for two polarizations can be gained under normal incidence. A simplified modal method is used to describe the mechanism of beam propagation and analyze diffraction behavior clearly in the grating. Most importantly, diffraction efficiencies numerically obtained by using RCWA can be in agreement with the rough theoretical analysis on account of the simplified modal method. Therefore, the connection-layer-based sandwiched three-port grating is significant for the further practical manufacture.

  15. Electroconvulsive therapy-induced brain functional connectivity predicts therapeutic efficacy in patients with schizophrenia: a multivariate pattern recognition study.

    Science.gov (United States)

    Li, Peng; Jing, Ri-Xing; Zhao, Rong-Jiang; Ding, Zeng-Bo; Shi, Le; Sun, Hong-Qiang; Lin, Xiao; Fan, Teng-Teng; Dong, Wen-Tian; Fan, Yong; Lu, Lin

    2017-05-11

    Previous studies suggested that electroconvulsive therapy can influence regional metabolism and dopamine signaling, thereby alleviating symptoms of schizophrenia. It remains unclear what patients may benefit more from the treatment. The present study sought to identify biomarkers that predict the electroconvulsive therapy response in individual patients. Thirty-four schizophrenia patients and 34 controls were included in this study. Patients were scanned prior to treatment and after 6 weeks of treatment with antipsychotics only (n = 16) or a combination of antipsychotics and electroconvulsive therapy (n = 13). Subject-specific intrinsic connectivity networks were computed for each subject using a group information-guided independent component analysis technique. Classifiers were built to distinguish patients from controls and quantify brain states based on intrinsic connectivity networks. A general linear model was built on the classification scores of first scan (referred to as baseline classification scores) to predict treatment response. Classifiers built on the default mode network, the temporal lobe network, the language network, the corticostriatal network, the frontal-parietal network, and the cerebellum achieved a cross-validated classification accuracy of 83.82%, with specificity of 91.18% and sensitivity of 76.47%. After the electroconvulsive therapy, psychosis symptoms of the patients were relieved and classification scores of the patients were decreased. Moreover, the baseline classification scores were predictive for the treatment outcome. Schizophrenia patients exhibited functional deviations in multiple intrinsic connectivity networks which were able to distinguish patients from healthy controls at an individual level. Patients with lower classification scores prior to treatment had better treatment outcome, indicating that the baseline classification scores before treatment is a good predictor for treatment outcome. CONNECTIVITY NETWORKS

  16. Moral competence and brain connectivity: A resting-state fMRI study.

    Science.gov (United States)

    Jung, Wi Hoon; Prehn, Kristin; Fang, Zhuo; Korczykowski, Marc; Kable, Joseph W; Rao, Hengyi; Robertson, Diana C

    2016-11-01

    Moral competence (MC) refers to the ability to apply certain moral orientations in a consistent and differentiated manner when judging moral issues. People greatly differ in terms of MC, however, little is known about how these differences are implemented in the brain. To investigate this question, we used functional magnetic resonance imaging and examined resting-state functional connectivity (RSFC) in n=31 individuals with MC scores in the highest 15% of the population and n=33 individuals with MC scores in the lowest 15%, selected from a large sample of 730 Master of Business Administration (MBA) students. Compared to individuals with lower MC, individuals with higher MC showed greater amygdala-ventromedial prefrontal connectivity, which may reflect better ability to cope with emotional conflicts elicited by moral dilemmas. Moreover, individuals with higher MC showed less inter-network connectivity between the amygdalar and fronto-parietal networks, suggesting a more independent operation of these networks. Our findings provide novel insights into how individual differences in moral judgment are associated with RSFC in brain circuits related to emotion processing and cognitive control. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. A connective tissue component of a myocardium: a new stage of studying of an old problem.

    Directory of Open Access Journals (Sweden)

    Gorbunov A.A.

    2007-01-01

    Full Text Available Majority of the myocardial cells belongs to its connective tissue component, which is built up of endomysial, perimysial and epimysial streaks. Cellular population exhibit remarkable polymorphism – among them are different types of fibroblasts, including myofibroblasts and fibroclasts, mast cells, macrophages, lymphoid cells. All of them product biologically active substances and serve as local regulators. Every cardiomyocyte connected merely to one fibroblast by the dense and nexus type of contacts, which allow mechanical and chemical interactions between these cells. Cardiomyocytes and connective tissue cells surrounded by the intercellular matrix, which consists fibrous and amorphous components. Collagen and elastic fibers make a framework for cardiac myocytes, which has a sophisticated spatial arrangement. Amorphous substance is a polyanionic buffer environment that provides trophic and regulatory processes in the myocardium. Intercellular matrix undergo permanent turnover, synthesis of the fiber proteins comes together with its degradation. Hitherto, myocardium is a multicomponent system that has a sophisticated mechanisms of regulation for the quantitative and qualitative composition of its elements.

  18. Combination of techniques for mapping structural and functional connectivity of soil erosion processes: a case study in a small watershed

    Science.gov (United States)

    Seeger, Manuel; Taguas, Encarnación; Brings, Christine; Wirtz, Stefan; Rodrigo Comino, Jesus; Albert, Enrique; Ries, Johabbes B.

    2016-04-01

    Sediment connectivity is understood as the interaction of sediment sources, the sinks and the pathways which connect them. During the last decade, the research on connectivity has increased, as it is crucial to understand the relation between the observed sediments at a certain point, and the processes leading them to that location. Thus, the knowledge of the biogeophysical features involved in sediment connectivity in an area of interest is essential to understand its functioning and to design treatments allowing its management, e. g. to reduce soil erosion. The structural connectivity is given by landscape elements which enable the production, transport and deposition of sediments, whereas the functional connectivity is understood here as variable processes that lead the sediments through a catchment. Therefore, 2 different levels of connectivity have been considered which superpose each other according to the catchments conditions. We studied the different connectivity features in a catchment almost completely covered by an olive grove. It is located south of Córdoba (Spain), close to the city of Puente Genil. The olive plantation type is of low productivity. The soil management was no tillage for the least 9 years. The farmer allow weed growing in the lanes although he applied herbicide treatment and tractor passes usually in the end of spring. Firstly, a detailed mapping of geomorphodynamic features was carried out. We identified spatially distributed areas of increased sheet-wash and crusting, but also areas where rill erosion has leadedto a high density of rills and small gullies. Especially within these areas rock outcrops up to several m² were mapped, showing like this (former) intense erosion processes. In addition, field measurements with different methodologies were applied on infiltration (single ring infiltrometers, rainfall simulations), soil permeability (Guelph permeameter), interrill erosion (rainfall simulator) and concentrated flow (rill

  19. Altered effective connectivity network of the amygdala in social anxiety disorder: a resting-state FMRI study.

    Directory of Open Access Journals (Sweden)

    Wei Liao

    Full Text Available The amygdala is often found to be abnormally recruited in social anxiety disorder (SAD patients. The question whether amygdala activation is primarily abnormal and affects other brain systems or whether it responds "normally" to an abnormal pattern of information conveyed by other brain structures remained unanswered. To address this question, we investigated a network of effective connectivity associated with the amygdala using Granger causality analysis on resting-state functional MRI data of 22 SAD patients and 21 healthy controls (HC. Implications of abnormal effective connectivity and clinical severity were investigated using the Liebowitz Social Anxiety Scale (LSAS. Decreased influence from inferior temporal gyrus (ITG to amygdala was found in SAD, while bidirectional influences between amygdala and visual cortices were increased compared to HCs. Clinical relevance of decreased effective connectivity from ITG to amygdala was suggested by a negative correlation of LSAS avoidance scores and the value of Granger causality. Our study is the first to reveal a network of abnormal effective connectivity of core structures in SAD. This is in support of a disregulation in predescribed modules involved in affect control. The amygdala is placed in a central position of dysfunction characterized both by decreased regulatory influence of orbitofrontal cortex and increased crosstalk with visual cortex. The model which is proposed based on our results lends neurobiological support towards cognitive models considering disinhibition and an attentional bias towards negative stimuli as a core feature of the disorder.

  20. Proteomic study related to vascular connections in watermelon scions grafted onto bottle-gourd rootstock under different light intensities.

    Directory of Open Access Journals (Sweden)

    Sowbiya Muneer

    Full Text Available Although grafting is broadly used in the production of crops, no information is available about the proteins involved in vascular connections between rootstock and scion. Similarly, proteome changes under the light intensities widely used for grafted seedlings are of practical use. The objective of this study was to determine the proteome of vascular connections using watermelon (Citrullus vulgaris Schrad. 'Sambok Honey' and 'Speed' as the scion and bottle gourd (Lagenaria siceraria Stanld. 'RS Dongjanggun' as the rootstock grown under different light intensities (25, 50, 75 and 100 μmol m-2 s-1. Our proteomic analysis revealed 24 and 27 differentially expressed proteins in 'Sambok Honey' and 'Speed', respectively, under different light intensities. The identified proteins were largely involved in ion binding, amino acid metabolism, transcriptional regulation and defense response. The enhancement of ion-binding, transcriptional regulation, amino acid metabolism, and defense response proteins suggests a strengthening of the connection between the rootstock and scion under high light intensity. Indeed, the accumulation of key enzymes in the biological processes described above appears to play an important role in the vascular connections of grafted seedlings. Moreover, it appears that 100 μmol m-2 s-1 results in better protein expression responses in grafted seedlings.

  1. A Triple Network Connectivity Study of Large-Scale Brain Systems in Cognitively Normal APOE4 Carriers

    Science.gov (United States)

    Wu, Xia; Li, Qing; Yu, Xinyu; Chen, Kewei; Fleisher, Adam S.; Guo, Xiaojuan; Zhang, Jiacai; Reiman, Eric M.; Yao, Li; Li, Rui

    2016-01-01

    The triple network model, consisting of the central executive network (CEN), salience network (SN) and default mode network (DMN), has been recently employed to understand dysfunction in core networks across various disorders. Here we used the triple network model to investigate the large-scale brain networks in cognitively normal apolipoprotein e4 (APOE4) carriers who are at risk of Alzheimer’s disease (AD). To explore the functional connectivity for each of the three networks and the effective connectivity among them, we evaluated 17 cognitively normal individuals with a family history of AD and at least one copy of the APOE4 allele and compared the findings to those of 12 individuals who did not carry the APOE4 gene or have a family history of AD, using independent component analysis (ICA) and Bayesian network (BN) approach. Our findings indicated altered within-network connectivity that suggests future cognitive decline risk, and preserved between-network connectivity that may support their current preserved cognition in the cognitively normal APOE4 allele carriers. The study provides novel sights into our understanding of the risk factors for AD and their influence on the triple network model of major psychopathology. PMID:27733827

  2. Proteomic study related to vascular connections in watermelon scions grafted onto bottle-gourd rootstock under different light intensities.

    Science.gov (United States)

    Muneer, Sowbiya; Ko, Chung Ho; Soundararajan, Prabhakaran; Manivnnan, Abinaya; Park, Yoo Gyeong; Jeong, Byoung Ryong

    2015-01-01

    Although grafting is broadly used in the production of crops, no information is available about the proteins involved in vascular connections between rootstock and scion. Similarly, proteome changes under the light intensities widely used for grafted seedlings are of practical use. The objective of this study was to determine the proteome of vascular connections using watermelon (Citrullus vulgaris Schrad.) 'Sambok Honey' and 'Speed' as the scion and bottle gourd (Lagenaria siceraria Stanld.) 'RS Dongjanggun' as the rootstock grown under different light intensities (25, 50, 75 and 100 μmol m-2 s-1). Our proteomic analysis revealed 24 and 27 differentially expressed proteins in 'Sambok Honey' and 'Speed', respectively, under different light intensities. The identified proteins were largely involved in ion binding, amino acid metabolism, transcriptional regulation and defense response. The enhancement of ion-binding, transcriptional regulation, amino acid metabolism, and defense response proteins suggests a strengthening of the connection between the rootstock and scion under high light intensity. Indeed, the accumulation of key enzymes in the biological processes described above appears to play an important role in the vascular connections of grafted seedlings. Moreover, it appears that 100 μmol m-2 s-1 results in better protein expression responses in grafted seedlings.

  3. Characterization of the fiber connectivity profile of the cerebral cortex in schizotypal personality disorder: A pilot study

    Directory of Open Access Journals (Sweden)

    Kai eLiu

    2016-05-01

    Full Text Available Schizotypal personality disorder (SPD is considered one of the classic disconnection syndromes. However, the specific cortical disconnectivity pattern has not been fully investigated. In this study, we aimed to explore significant alterations in whole-cortex structural connectivity in SPD individuals (SPDs by combining the techniques of brain surface morphometry and white matter (WM tractography. Diffusion and structural MR data were collected from twenty subjects with SPD (all males; age, 19.7 ± 0.9 yrs and eighteen healthy controls (all males; age, 20.3 ± 1.0 yrs. To measure the structural connectivity for a given unit area of the cortex, the fiber connectivity density (FiCD value was proposed and calculated as the sum of the fractional anisotropy of all the fibers connecting to that unit area in tractography. Then, the resultant whole-cortex FiCD maps were compared in a vertex-wise manner between SPDs and controls. Compared with normal controls, SPDs showed significantly decreased FiCD in the rostral middle frontal gyrus (crossing BA9 and BA10 and significantly increased FiCD in the anterior part of the fusiform/inferior temporal cortex (P < 0.05, Monte Carlo simulation corrected. Moreover, the gray matter volume extracted from the left rostral middle frontal cluster was observed to be significantly greater in the SPD group (P = 0.02. Overall, this study identifies a decrease in connectivity in the left middle frontal cortex as a key neural deficit at the whole-cortex level in SPD, thus providing insight into its neuropathological basis.

  4. Characterization of the Fiber Connectivity Profile of the Cerebral Cortex in Schizotypal Personality Disorder: A Pilot Study.

    Science.gov (United States)

    Liu, Kai; Zhang, Teng; Zhang, Qing; Sun, Yueji; Wu, Jianlin; Lei, Yi; Chu, Winnie C W; Mok, Vincent C T; Wang, Defeng; Shi, Lin

    2016-01-01

    Schizotypal personality disorder (SPD) is considered one of the classic disconnection syndromes. However, the specific cortical disconnectivity pattern has not been fully investigated. In this study, we aimed to explore significant alterations in whole-cortex structural connectivity in SPD individuals (SPDs) by combining the techniques of brain surface morphometry and white matter tractography. Diffusion and structural MR data were collected from 20 subjects with SPD (all males; age, 19.7 ± 0.9 years) and 18 healthy controls (all males; age, 20.3 ± 1.0 years). To measure the structural connectivity for a given unit area of the cortex, the fiber connectivity density (FiCD) value was proposed and calculated as the sum of the fractional anisotropy of all the fibers connecting to that unit area in tractography. Then, the resultant whole-cortex FiCD maps were compared in a vertex-wise manner between SPDs and controls. Compared with normal controls, SPDs showed significantly decreased FiCD in the rostral middle frontal gyrus (crossing BA 9 and BA 10) and significantly increased FiCD in the anterior part of the fusiform/inferior temporal cortex (P < 0.05, Monte Carlo simulation corrected). Moreover, the gray matter volume extracted from the left rostral middle frontal cluster was observed to be significantly greater in the SPD group (P = 0.02). Overall, this study identifies a decrease in connectivity in the left middle frontal cortex as a key neural deficit at the whole-cortex level in SPD, thus providing insight into its neuropathological basis.

  5. Gendered Connections

    DEFF Research Database (Denmark)

    Jensen, Steffen Bo

    2009-01-01

    This article explores the gendered nature of urban politics in Cape Town by focusing on a group of female, township politicians. Employing the Deleuzian concept of `wild connectivity', it argues that these politically entrepreneurial women were able to negotiate a highly volatile urban landscape...... space also drew on quite traditional notions of female respectability. Furthermore, the article argues, the form of wild connectivity to an extent was a function of the political transition, which destabilized formal structures of gendered authority. It remains a question whether this form...... of connectivity might endure, as Capetonian politics assumes a post-apartheid structure....

  6. Sinus node, phrenic nerve and electrical connections between superior vena cava and right atrium: lessons learned from a prospective study

    Institute of Scientific and Technical Information of China (English)

    LONG De-yong; MA Chang-sheng; JIANG Hong; DONG Jian-zeng; LIU Xing-peng; HUANG He; TANG Yan-hong; WU Gang; HUANG Cong-xin

    2009-01-01

    Background When performing superior vena cava isolation, the major concerns are inadvertent ablation on sinus node and right phrenic nerve. However, little is known about the spatial relationship of electrical connections between superior vena cava and right atrium with the sinus node and phrenic nerve locations among individual patients.Methods We studied 87 patients (male/female 60/27, mean age of (51±9) years) with atrial fibrillation. Before superior vena cava isolation, the sinus node site was defined by right atrium activation mapping during sinus rhythm and the right phrenic nerve site was localized via pacing manoeuvre. Superior vena cava was isolated by ablation at the electrical connection under the guidance of circular mapping catheter. The sites of sinus node, phrenic nerve and electrical connections were noted. Continuous variables were compared using Student's t test. A P value <0.05 was considered statistically significant.Results Right atrium activation mapping revealed that the sinus node located at the anterior lateral segment of superior vena cava-right atrium junction in all patients, in 82 patients with detectable diaphragmatic stimulations, the phrenic nerve sites were predominantly at the lateral segment (70/82) with anterior lateral and anterior segments for a few patients. A total of 165 electrical connections were located among all 87 patients, and this averaged 1.8±0.6 (1-3) per patient. The anterior septum (72 patients (43.6%)), the anterior wall (40 (24.2%)), and the posterior septum (35 (35.4%)) of superior vena cava-right atrium junction were the electrical connection regular sites. Superior vena cava was isolated in all patients. Two patients developed sinus bradycardia, with 3 mild superior vena cava stenosis and 2 phrenic nerve palsy.Conclusions The sinus node, phrenic nerve and electrical connection sites were distributed along the superior vena cava-right atrium junctions at expected locations for most patients. The electrical

  7. A method for using blocked and event-related fMRI data to study "resting state" functional connectivity.

    Science.gov (United States)

    Fair, Damien A; Schlaggar, Bradley L; Cohen, Alexander L; Miezin, Francis M; Dosenbach, Nico U F; Wenger, Kristin K; Fox, Michael D; Snyder, Abraham Z; Raichle, Marcus E; Petersen, Steven E

    2007-03-01

    Resting state functional connectivity MRI (fcMRI) has become a particularly useful tool for studying regional relationships in typical and atypical populations. Because many investigators have already obtained large data sets of task-related fMRI, the ability to use this existing task data for resting state fcMRI is of considerable interest. Two classes of data sets could potentially be modified to emulate resting state data. These data sets include: (1) "interleaved" resting blocks from blocked or mixed blocked/event-related sets, and (2) residual timecourses from event-related sets that lack rest blocks. Using correlation analysis, we compared the functional connectivity of resting epochs taken from a mixed blocked/event-related design fMRI data set and the residuals derived from event-related data with standard continuous resting state data to determine which class of data can best emulate resting state data. We show that, despite some differences, the functional connectivity for the interleaved resting periods taken from blocked designs is both qualitatively and quantitatively very similar to that of "continuous" resting state data. In contrast, despite being qualitatively similar to "continuous" resting state data, residuals derived from event-related design data had several distinct quantitative differences. These results suggest that the interleaved resting state data such as those taken from blocked or mixed blocked/event-related fMRI designs are well-suited for resting state functional connectivity analyses. Although using event-related data residuals for resting state functional connectivity may still be useful, results should be interpreted with care.

  8. 珊瑚礁连通性研究进展%Progress in Studies of Connectivity among Coral Reefs

    Institute of Scientific and Technical Information of China (English)

    吴瑞

    2016-01-01

    Previous studies of the connectivity among coral reefs during recent 20 years in other countries were reviewed. Methods of studying the connectivity among coral reefs were summarized. The signiifcance of the “study of connectivity among coral reefs” to ecosystem management of coral reefs was described. Studies of the connectivity among coral reefs have just started in China, leaving a large gap between China and foreign countries. Future studies should be strengthened in the diffusion path of coral larvae, genetic differentiation within and between populations, genetic distance, and gene lfow. The corridors of coral larvae diffusion in the territory of China Sea should be protected.%综述了国外近20a珊瑚礁连通性的研究简史,总结了珊瑚礁连通性研究的方法,阐述了“珊瑚礁连通性”的研究对珊瑚礁生态系统管理的重要意义。中国的珊瑚礁连通性研究刚起步,离国外还有很大差距,今后应加强珊瑚幼虫扩散路径、珊瑚群体内(群体间)遗传分化、遗传距离、基因流的研究,对我国海域珊瑚幼虫扩散的走廊加以保护。

  9. Xu Fuguan’s Concept of Anxiety and Its Connection to Religious Studies

    Directory of Open Access Journals (Sweden)

    Tea SERNELJ

    2013-11-01

    Full Text Available Although Xu Fuguan (1903–1982 belongs to the most important representatives of the Modern Confucian intellectual movement, he is rather unknown outside China. However, his concept of “anxiety” (youhuan yishi 憂患意識 is not only relevant for the recognition of the special characteristics, which determines the ideological and political structure of ancient Chinese society, but also for the intercultural elaboration of Jaspers’s “axial age” theory. This article introduces this concept to the European academic readership, and provides an analysis of its connection to the Modern Confucian hypothesis regarding the absence of an external God (or Deities in classical Chinese culture.

  10. Study of the Induction Motor with Arbitrary Stator Winding In Wye-Connection

    Directory of Open Access Journals (Sweden)

    Adriana Purece- Abrudan

    2009-05-01

    Full Text Available The anisotropy of a cage rotor is utilized to determine the angular position of the rotor in an induction machine. The switching transients generated by a pulsewidth controlled inverter serve as test signals. The response of the three inverter terminal currents is exploited to derive a quasi-instantaneous rotor position signal. The position is sensed at the inverter through the 3-phase motor cable by measuring the current derivatives. The method is applicable to induction motors having the stator windings connected either in wye or in delta.

  11. Study on contact pressure at pin connection detail; Pin setsugobu no sesshokuatsu ni taisuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Miki, C.; Anami, K. [Tokyo Institute of Technology, Tokyo (Japan); Suzuki, M. [Ministry of Construction, Tokyo (Japan); Ohashi, H. [Honshu-Shikoku Bridge Authority, Tokyo (Japan)

    1997-07-21

    Contact pressure between pin and pin plate is discussed by FEM and UT from the point of view of the connection detail of hanger lope of long span suspension bridge. Application of the UT to the 25S surface specimen (and smoother surface) is effective. The results of UT and FEM distribution of contact pressure near the center of plate almost agree with the Hertz law. However near the surface of pin plate the contact pressure and plate width of large contact pressure region increase larger than those near contact pressure and plate width of large contact pressure region increase larger than those near center of pin plate. 12 refs., 17 figs.

  12. Defining Boundaries for Ecosystem-Based Management: A Multispecies Case Study of Marine Connectivity across the Hawaiian Archipelago

    Directory of Open Access Journals (Sweden)

    Robert J. Toonen

    2011-01-01

    Full Text Available Determining the geographic scale at which to apply ecosystem-based management (EBM has proven to be an obstacle for many marine conservation programs. Generalizations based on geographic proximity, taxonomy, or life history characteristics provide little predictive power in determining overall patterns of connectivity, and therefore offer little in terms of delineating boundaries for marine spatial management areas. Here, we provide a case study of 27 taxonomically and ecologically diverse species (including reef fishes, marine mammals, gastropods, echinoderms, cnidarians, crustaceans, and an elasmobranch that reveal four concordant barriers to dispersal within the Hawaiian Archipelago which are not detected in single-species exemplar studies. We contend that this multispecies approach to determine concordant patterns of connectivity is an objective and logical way in which to define the minimum number of management units and that EBM in the Hawaiian Archipelago requires at least five spatially managed regions.

  13. A social work study on relationship between school connection and academic failure among guided schoolchildren in city of Esfahan

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Abedi

    2013-03-01

    Full Text Available Academic failure is one of the most important issues in educational systems and there are several attempts held to prevent such issues. In this paper, we study the relationship between school connection and academic failure among some high schools students in city of Esfahan, Iran during the academic calendar of 2011-2012. The study chooses a sample of 377 students based on clustering sampling technique and using Pearson correlation test as well as stepwise multiple regression technique, the relationship between school connection and academic failure is investigated. The result of Pearson correlation ratio indicates that there is meaningful relationship between these two components. In addition, the result of regression analysis indicates that 32% of students’ academic failure is determined by this ratio.

  14. Toward on-chip functional neuronal networks: computational study on the effect of synaptic connectivity on neural activity.

    Science.gov (United States)

    Foroushani, Armin Najarpour; Ghafar-Zadeh, Ebrahim

    2014-01-01

    This paper presents a new unified computational-experimental approach to study the role of the synaptic activity on the activity of neurons in the small neuronal networks (NNs). In a neuronal tissue/organ, this question is investigated with higher complexities by recording action potentials from population of neurons in order to find the relationship between connectivity and the recorded activities. In this approach, we study the dynamics of very small cortical neuronal networks, which can be experimentally synthesized on chip with constrained connectivity. Multi-compartmental Hodgkin-Huxley model is used in NEURON software to reproduce cells by extracting the experimental data from the synthesized NNs. We thereafter demonstrate how the type of synaptic activity affects the network response to specific spike train using the simulation results.

  15. HR Connect

    Data.gov (United States)

    US Agency for International Development — HR Connect is the USAID HR personnel system which allows HR professionals to process HR actions related to employee's personal and position information. This system...

  16. Advice taking from humans and machines: an fMRI and effective connectivity study

    Directory of Open Access Journals (Sweden)

    Kimberly Goodyear

    2016-11-01

    Full Text Available With new technological advances, advice can come from different sources such as machines or humans, but how individuals respond to such advice and the neural correlates involved need to be better understood. We combined functional MRI and multivariate Granger causality analysis with an X-ray luggage-screening task to investigate the neural basis and corresponding effective connectivity involved with advice utilization from agents framed as experts. Participants were asked to accept or reject good or bad advice from a human or machine agent with low reliability (high false alarm rate. We showed that unreliable advice decreased performance overall and participants interacting with the human agent had a greater depreciation of advice utilization during bad advice compared to the machine agent. These differences in advice utilization can be perceivably due to reevaluation of expectations arising from association of dispositional credibility for each agent. We demonstrated that differences in advice utilization engaged brain regions that may be associated with evaluation of personal characteristics and traits (precuneus, posterior cingulate cortex, temporoparietal junction and interoception (posterior insula. We found that the right posterior insula and left precuneus were the drivers of the advice utilization network that were reciprocally connected to each other and also projected to all other regions. Our behavioral and neuroimaging results have significant implications for society because of progressions in technology and increased interactions with machines.

  17. Decreased prefrontal lobe interhemispheric functional connectivity in adolescents with internet gaming disorder: a primary study using resting-state FMRI.

    Directory of Open Access Journals (Sweden)

    Yao Wang

    Full Text Available Recent neuroimaging studies have shown that people with Internet gaming disorder (IGD have structural and functional abnormalities in specific brain areas and connections. However, little is known about the alterations of the interhemispheric resting-state functional connectivity (rsFC in participants with IGD. In the present study, we used a newly developed voxel-mirrored homotopic connectivity (VMHC method to investigate the interhemispheric rsFC of the whole brain in participants with IGD.We compared interhemispheric rsFC between 17 participants with IGD and 24 healthy controls, group-matched on age, gender, and education status. All participants were provided written informed consent. Resting-state functional and structural magnetic resonance images were acquired for all participants. The rsFC between bilateral homotopic voxels was calculated. Regions showing abnormal VMHC in IGD participants were adopted as regions of interest for correlation analyses.Compared to healthy controls, IGD participants showed decreased VMHC between the left and right superior frontal gyrus (orbital part, inferior frontal gyrus (orbital part, middle frontal gyrus and superior frontal gyrus. Further analyses showed Chen Internet Addiction Scale (CIAS-related VMHC in superior frontal gyrus (orbital part and CIAS (r = -0.55, p = 0.02, uncorrected.Our findings implicate the important role of altered interhemispheric rsFC in the bilateral prefrontal lobe in the neuropathological mechanism of IGD, and provide further supportive evidence for the reclassification of IGD as a behavioral addiction.

  18. The Elusive Role of the Left Temporal Pole (BA38 in Language: A Preliminary Meta-Analytic Connectivity Study

    Directory of Open Access Journals (Sweden)

    Alfredo Ardila

    2014-01-01

    Full Text Available It has been suggested that the left temporal pole (Brodmann area 38 (BA38 participates in diverse language functions, including semantic processing, speech comprehension, and naming. Utilizing the activation likelihood estimation (ALE, a meta-analytic connectivity study was conducted to further our understanding on the role of BA38 in language. Departing from the BrainMap functional database, 11 papers corresponding to 12 paradigms including 201 participants were selected. Initially, P<0.01 was employed as the significance level, resulting in the presence of four different activation clusters. However, when the significance level was lowered to P<0.05, sixteen activation clusters appeared, including classical language areas such as Broca’s and Wernicke’s areas. It was concluded that (1 this meta-analytic connectivity study suggests the presence of two major connection circuits involving BA38; one is related to language, while the other may be involved in visuospatial and integrative audiovisual functions. Furthermore, (2 BA38 also contributes to various brain networks supporting linguistic processes related not only to language comprehension but also to language production.

  19. Does Functional Connectivity Provide a Marker for Cognitive Rehabilitation Effects in Alzheimer’s Disease? An Interventional Study

    Science.gov (United States)

    Ochmann, Sina; Dyrba, Martin; Grothe, Michel J.; Kasper, Elisabeth; Webel, Steffi; Hauenstein, Karlheinz; Teipel, Stefan J.

    2017-01-01

    Background: Cognitive rehabilitation (CR) is a cognitive intervention for patients with Alzheimer’s disease (AD) that aims to maintain everyday competences. The analysis of functional connectivity (FC) in resting-state functional MRI has been used to investigate the effects of cognitive interventions. Objectives: We evaluated the effect of CR on the default mode network FC in a group of patients with mild AD, compared to an active control group. Methods: We performed a three-month interventional study including 16 patients with a diagnosis of AD. The intervention group (IG) consisted of eight patients, performing twelve sessions of CR. The active control group (CG) performed a standardized cognitive training. We used a seed region placed in the posterior cingulate cortex (PCC) for FC analysis, comparing scans acquired before and after the intervention. Effects were thresholded at a significance of p < 0.001 (uncorrected) and a minimal cluster size of 50 voxels. Results: The interaction of group by time showed a higher increase of PCC connectivity in IG compared to CG in the bilateral cerebellar cortex. CG revealed widespread, smaller clusters of higher FC increase compared with IG. Across all participants, an increase in quality of life was associated with connectivity increase over time in the bilateral precuneus. Conclusions: CR showed an effect on the FC of the DMN in the IG. These effects need further study in larger samples to confirm if FC analysis may suit as a surrogate marker for the effect of cognitive interventions in AD. PMID:28372326

  20. Development of functional connectivity during adolescence: a longitudinal study using an action-observation paradigm.

    Science.gov (United States)

    Shaw, Daniel J; Grosbras, Marie-Helene; Leonard, Gabriel; Pike, G Bruce; Paus, Tomáš

    2011-12-01

    Successful interpersonal interactions rely on an ability to read the emotional states of others and to modulate one's own behavior in response. The actions of others serve as valuable social stimuli in this respect, offering the observer an insight into the actor's emotional state. Social cognition continues to mature throughout adolescence. Here we assess longitudinally the development of functional connectivity during early adolescence within two neural networks implicated in social cognition: one network of brain regions consistently engaged during action observation and another one associated with mentalizing. Using fMRI, we reveal a greater recruitment of the social-emotional network during the observation of angry hand actions in male relative to female adolescents. These findings are discussed in terms of known sex differences in adolescent social behavior.

  1. Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

    Science.gov (United States)

    Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

    2016-08-01

    According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

  2. Improved QSPR Study of Diamagnetic Susceptibilities for Organic Compounds Using Two Novel Molecular Connectivity Indexes

    Institute of Scientific and Technical Information of China (English)

    MU Lailong; HE Hongmei; YANG Weihua

    2009-01-01

    For predicting the molar diamagnetic susceptibilities of organic compounds, a variable molecular connectivity index mχ' and its converse index mχ" based on adjacency matrix of molecular graphs and the variable atomic valence connectivity index δi' were proposed. The optimal values of parameters x, a, and y included in definition of δi', mχ' and mχ" can be found by an optimization method. When x=2.9, a= 1.10, and y=0.36, a good five-parameter model for the molar diamagnetic susceptibilities can be constructed from 0χ',1χ',2χ',1χ" and 2χ" by using the best subset re-gression analysis method. The correlation coefficient r, standard error s, and average absolute deviation of the mul-tilinear regression (MLR) model are 0.9930, 4.96 cgs, and 3.74 cgs, respectively, for the 721 organic compounds (training set). The cross-validation by using the leave-one-out method demonstrates that the MLR model is highly reliable from the point of view of statistics. The average absolute deviation of predicted values of the molar dia-magnetic susceptibility of another 360 organic compounds (test set) is 4.37 cgs for the MLR model. The results show that the current method is more effective than literature methods for estimating the molar diamagnetic suscep-tibility of an organic compound. The MLR method can provide an acceptable model for the prediction of the molar diamagnetic susceptibilities of organic compounds.

  3. The modulation of brain functional connectivity with manual acupuncture in healthy subjects:An electroencephalograph case study

    Institute of Scientific and Technical Information of China (English)

    Yi Guo-Sheng; Wang Jiang; Han Chun-Xiao; Deng Bin; Wei Xi-Le; Li Nuo

    2013-01-01

    Manual acupuncture is widely used for pain relief and stress control.Previous studies on acupuncture have shown its modulatory effects on the functional connectivity associated with one or a few preselected brain regions.To investigate how manual acupuncture modulates the organization of functional networks at a whole-brain level,we acupuncture at ST36 of a fight leg to obtain electroencephalograph (EEG) signals.By coherence estimation,we determine the synchronizations between all pairwise combinations of EEG channels in three acupuncture states.The resulting synchronization matrices are converted into functional networks by applying a threshold,and the clustering coefficients and path lengths are computed as a function of threshold.The results show that acupuncture can increase functional connections and synchronizations between different brain areas.For a wide range of thresholds,the clustering coefficient during acupuncture and postacupuncture period is higher than that during the pre-acupuncture control period,whereas the characteristic path length is shorter.We provide further support for the presence of "small-world" network characteristics in functional networks by using acupuncture.These preliminary results highlight the beneficial modulations of functional connectivity by manual acupuncture,which could contribute to the understanding of the effects of acupuncture on the entire brain,as well as the neurophysiological mechanisms underlying acupuncture.Moreover,the proposed method may be a useful approach to the further investigation of the complexity of patterns of interrelations between EEG channels.

  4. DSRC versus 4G-LTE for Connected Vehicle Applications: A Study on Field Experiments of Vehicular Communication Performance

    Directory of Open Access Journals (Sweden)

    Zhigang Xu

    2017-01-01

    Full Text Available Dedicated short-range communication (DSRC and 4G-LTE are two widely used candidate schemes for Connected Vehicle (CV applications. It is thus of great necessity to compare these two most viable communication standards and clarify which one can meet the requirements of most V2X scenarios with respect to road safety, traffic efficiency, and infotainment. To the best of our knowledge, almost all the existing studies on comparing the feasibility of DRSC or LTE in V2X applications use software-based simulations, which may not represent realistic constraints. In this paper, a Connected Vehicle test-bed is established, which integrates the DSRC roadside units, 4G-LTE cellular communication stations, and vehicular on-board terminals. Three Connected Vehicle application scenarios are set as Collision Avoidance, Traffic Text Message Broadcast, and Multimedia File Download, respectively. A software tool is developed to record GPS positions/velocities of the test vehicles and record certain wireless communication performance indicators. The experiments have been carried out under different conditions. According to our results, 4G-LTE is more preferred for the nonsafety applications, such as traffic information transmission, file download, or Internet accessing, which does not necessarily require the high-speed real-time communication, while for the safety applications, such as Collision Avoidance or electronic traffic sign, DSRC outperforms the 4G-LTE.

  5. Connected Traveler

    Energy Technology Data Exchange (ETDEWEB)

    2016-06-01

    The Connected Traveler framework seeks to boost the energy efficiency of personal travel and the overall transportation system by maximizing the accuracy of predicted traveler behavior in response to real-time feedback and incentives. It is anticipated that this approach will establish a feedback loop that 'learns' traveler preferences and customizes incentives to meet or exceed energy efficiency targets by empowering individual travelers with information needed to make energy-efficient choices and reducing the complexity required to validate transportation system energy savings. This handout provides an overview of NREL's Connected Traveler project, including graphics, milestones, and contact information.

  6. Modeling habitat connectivity to inform reintroductions: a case study with the Chiricahua Leopard Frog

    Science.gov (United States)

    Jarchow, Christopher J.; Hossack, Blake R.; Sigafus, Brent H.; Schwalbe, Cecil R.; Muths, Erin L.

    2016-01-01

    Managing species with intensive tools such as reintroduction may focus on single sites or entire landscapes. For vagile species, long-term persistence will require colonization and establishment in neighboring habitats. Therefore, both suitable colonization sites and suitable dispersal corridors between sites are required. Assessment of landscapes for both requirements can contribute to ranking and selection of reintroduction areas, thereby improving management success. Following eradication of invasive American Bullfrogs (Lithobates catesbeianus) from most of Buenos Aires National Wildlife Refuge (BANWR; Arizona, United States), larval Chiricahua Leopard Frogs (Lithobates chiricahuensis) from a private pond were reintroduced into three stock ponds. Populations became established at all three reintroduction sites followed by colonization of neighboring ponds in subsequent years. Our aim was to better understand colonization patterns by the federally threatened L. chiricahuensis which could help inform other reintroduction efforts. We assessed the influence of four landscape features on colonization. Using surveys from 2007 and information about the landscape, we developed a habitat connectivity model, based on electrical circuit theory, that identified potential dispersal corridors after explicitly accounting for imperfect detection of frogs. Landscape features provided little insight into why some sites were colonized and others were not, results that are likely because of the uniformity of the BANWR landscape. While corridor modeling may be effective in more-complex landscapes, our results suggest focusing on local habitat will be more useful at BANWR. We also illustrate that existing data, even when limited in spatial or temporal resolution, can provide information useful in formulating management actions.

  7. Strategic and integrated planning for healthy, connected cities: Chattanooga case study.

    Science.gov (United States)

    Elwell Bostrom, Holly; Shulaker, Bianca; Rippon, Jasmin; Wood, Rick

    2017-02-01

    The United States is facing unprecedented health challenges - such as obesity and cardiovascular disease - many of which are related to a lack of or insufficient physical activity. Maintaining or creating parks and other public recreation facilities that promote physical activity is particularly important for combating these. This brief describes a strategic planning initiative, known as "Healthy, Connected Chattanooga." The City of Chattanooga, Tennessee, partnered with The Trust for Public Land, a national nonprofit organization, to analyze the city for physical activity opportunities and identify areas where interventions were of highest need. Interventions include the creation of new parks and the activation of existing ones through the installation of fitness facilities known as Fitness Zones®. Maps and an on-line decision-support tool (web portal) were developed between 2013 and 2015, and are being used by the city to make strategic investment decisions. The decision-support analysis described in this brief has engaged a wide variety of stakeholders, opened the door to a broader base of funding sources for health-related interventions, and provided evidence for discussions about equity, access to resources, and prioritization of future projects. This brief presents a framework for integrating scientific models with community and social metrics, enabling more complete and accurate understanding of cities and the identification of more equitable, strategic, and investable solutions to current and pressing challenges. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Cement-base bearing pads mortar for connections in the precast concrete: study of surface roughness

    Directory of Open Access Journals (Sweden)

    M. K. El Debs

    Full Text Available Bearing pads are used in precast concrete connections to avoid concentrated stresses in the contact area between the precast elements. In the present research, the bearing pads are Portland cement mortar with styrene-butadiene latex (SB, lightweight aggregate (expanded vermiculite-term and short fibers (polypropylene, glass and PVA, in order to obtain a material with low modulus of elasticity and high tenacity, compared with normal Portland cement mortar. The objective of this paper is to analyze the influence of surface roughness on the pads and test other types of polypropylene fibers. Tests were carried out to characterize the composite and test on bearing pads. Characterization tests show compressive strength of 41MPa and modulus of elasticity of 12.8GPa. The bearing pads tests present 30% reduction of stiffness in relation to a reference mortar. The bearing pads with roughness on both sides present a reduction up to 30% in stiffness and an increase in accumulated deformation of more than 120%, regarding bearing pads with both sides smooth.

  9. Connected leadership: Jeremiah 8:18-9:3 – a case study

    Directory of Open Access Journals (Sweden)

    W.J. Wessels

    2010-07-01

    Full Text Available The purpose of this article is to address the matter of connected leadership. The point of departure is a biblical passage from Jeremiah 8:18-9:3. The focus of this article is confined to the aspect of connectedness and related issues. The argument put forward is that the rhetorical nature of texts has the ability to engage many readers over time and generations. Not only did the poetic nature of Jeremiah 8:18-9:3 convey the words once spoken by a prophet, but the rhetoric also conveyed the passion of the prophet and of Yahweh for the wounded and broken people of Judah. Added to that is the fact that within the Christian tradition the belief is that the text will find meaning in new contexts as well. Jeremiah 8:18-9:3 brings to the table an element that leaders – especially religious and Christian leaders – need to take note of. Leaders should answer to a “higher power” and to ethical norms because of connectedness to this ‘‘higher power”. As a leader, Jeremiah identified with his people and their woeful condition. But because of his connectedness to Yahweh, he was willing to confront them and point out their wrongdoings. He was not prepared to sacrifice his beliefs and convictions for the sake of popularity.

  10. Principle study on the signal connection at transabdominal fetal pulse oximetry

    Directory of Open Access Journals (Sweden)

    Böttrich Marcel

    2016-09-01

    Full Text Available Transabdominal fetal pulse oximetry is an approach to measure oxygen saturation of the unborn child non-invasively. The principle of pulse oximetry is applied to the abdomen of a pregnant woman, such that the measured signal includes both, the maternal and the fetal pulse curve. One of the major challenges is to extract the shape of the fetal pulse curve from the mixed signal for computation of the oxygen saturation. In this paper we analyze the principle kind of connection of the fetal and maternal pulse curves in the measured signal. A time varying finite element model is used to rebuild the basic measurement environment, including a bulk tissue and two independently pulsing arteries to model the fetal and maternal blood circuit. The distribution of the light fluence rate in the model is computed by applying diffusion equation. From the detectors we extracted the time dependent fluence rate and analyzed the signal regarding its components. The frequency spectra of the signals show peaks at the fetal and maternal basic frequencies. Additional signal components are visible in the spectra, indicating multiplicative coupling of the fetal and maternal pulse curves. We conclude that the underlying signal model of algorithms for robust extraction of the shape of the fetal pulse curve, have to consider additive and multiplicative signal coupling.

  11. Order-theoretical connectivity

    Directory of Open Access Journals (Sweden)

    T. A. Richmond

    1990-01-01

    Full Text Available Order-theoretically connected posets are introduced and applied to create the notion of T-connectivity in ordered topological spaces. As special cases T-connectivity contains classical connectivity, order-connectivity, and link-connectivity.

  12. Getting Connected

    Science.gov (United States)

    Larkin, Patrick

    2011-01-01

    That the world outside schools is changing faster than ever is old news. Unfortunately, that the world "inside" schools is changing at a glacial pace is even older news. As school leaders, principals have an important choice to make as they move into the second decade of the 21st century. School leaders have a moral obligation to connect and…

  13. Connecting dots

    DEFF Research Database (Denmark)

    Murakami, Kyoko; Jacobs, Rachel L.

    2017-01-01

    of connecting the dots of recalled moments of individual family members lives and is geared towards building a family’s shared future for posterity. Lastly, we consider a wider implication of family reminiscence in terms of human development. http://www.infoagepub.com/products/Memory-Practices-and-Learning...

  14. Human Connections and Their Roles in the Occupational Well-being of Healthcare Professionals: A Study on Loneliness and Empathy

    Directory of Open Access Journals (Sweden)

    Jorge Soler-Gonzalez

    2017-08-01

    Full Text Available Human connections are key to the promotion of health and prevention of illness; moreover, illness can cause deterioration of human connections. Healthcare professional–patient relationships are key to ensuring the preservation of adequate human connections. It is important for healthcare professionals to develop their ability to foster satisfactory human connections because: (i they represent social support for patients; and (ii they prevent work-related stress. In this study we assessed the relationship between absence (loneliness and presence (empathy of human connections with the occupational well-being of healthcare professionals. The Scale of Collateral Effects, which measures somatization, exhaustion, and work alienation; the Jefferson Scale of Empathy; and the Social and Emotional Loneliness Scale for Adults, were mailed to 628 healthcare professionals working in Spanish public healthcare institutions. The following explanatory variables were used to evaluate work well-being: (a empathy, as a professional competence; (b loneliness, age, and family burden, as psychological indicators; and (c professional experience, work dedication, and salary, as work indicators. Comparison, correlation, and regression analyses were performed to measure the relationships among these variables and occupational well-being. Of 628 surveys mailed, 433 (69% response rate were returned fully completed. Adequate reliability was confirmed for all instruments. The entire sample was divided into four groups, based on the combined variable, “occupation by sex.” Comparative analyses demonstrated differences among “occupation by sex” groups in collateral effects (p = 0.03 and empathy (p = 0.04, but not loneliness (p = 0.84. Inverse associations between empathy and collateral effects were confirmed for somatization (r = -0.16; p < 0.001, exhaustion (r = -0.14; p = 0.003, and work alienation (r = -0.16; p < 0.001. Furthermore, loneliness was positively

  15. Generalized connectivity of graphs

    CERN Document Server

    Li, Xueliang

    2016-01-01

    Noteworthy results, proof techniques, open problems and conjectures in generalized (edge-) connectivity are discussed in this book. Both theoretical and practical analyses for generalized (edge-) connectivity of graphs are provided. Topics covered in this book include: generalized (edge-) connectivity of graph classes, algorithms, computational complexity, sharp bounds, Nordhaus-Gaddum-type results, maximum generalized local connectivity, extremal problems, random graphs, multigraphs, relations with the Steiner tree packing problem and generalizations of connectivity. This book enables graduate students to understand and master a segment of graph theory and combinatorial optimization. Researchers in graph theory, combinatorics, combinatorial optimization, probability, computer science, discrete algorithms, complexity analysis, network design, and the information transferring models will find this book useful in their studies.

  16. Food connections: A qualitative exploratory study of weight- and eating-related distress in families affected by advanced cancer.

    Science.gov (United States)

    Hopkinson, J B

    2016-02-01

    Weight loss and eating problems are common in cancer and have a profound effect on quality of life. They are symptoms of cancer cachexia syndrome. This paper examines interdependency between advanced cancer patient and family carer experience of weight- and eating-related problems, leading to proposition of how weight- and eating-related distress might be alleviated in both patients and their family members. The study was of cross-sectional design. Interpretive phenomenology informed the analytic process. Patient participants had advanced cancer and concern about weight and/or eating. Semi-structured interviews were conducted with 31 patient-spouse/partner dyads (62 interviews), which focused on weight loss and eating problems in the patient and how these had been managed. This study found change in weight and eating habits in advanced cancer to disrupt food connections. Food connects us with others physically by fuelling the body and sustaining physical activity and life, emotionally by communicating feelings about self and others, and socially by providing a reason for sharing time with others. The study found three dyadic responses to disruption in food connections; dual acceptance, dual resistance and mismatched resistance. They are of interest, because they can help discriminate between those patient-family carer dyads who might benefit from psychosocial interventions and those who will cope without such help. The findings challenge clinicians and researchers to seek ways of aiding not only with concerns of the individual patients and carers, but also with interactions between distressed family members affected by symptoms of cancer cachexia syndrome. Copyright © 2015 The Author. Published by Elsevier Ltd.. All rights reserved.

  17. Alterations in Cortical Sensorimotor Connectivity following Complete Cervical Spinal Cord Injury: A Prospective Resting-State fMRI Study.

    Directory of Open Access Journals (Sweden)

    Akinwunmi Oni-Orisan

    Full Text Available Functional magnetic resonance imaging (fMRI studies have demonstrated alterations during task-induced brain activation in spinal cord injury (SCI patients. The interruption to structural integrity of the spinal cord and the resultant disrupted flow of bidirectional communication between the brain and the spinal cord might contribute to the observed dynamic reorganization (neural plasticity. However, the effect of SCI on brain resting-state connectivity patterns remains unclear. We undertook a prospective resting-state fMRI (rs-fMRI study to explore changes to cortical activation patterns following SCI. With institutional review board approval, rs-fMRI data was obtained in eleven patients with complete cervical SCI (>2 years post injury and nine age-matched controls. The data was processed using the Analysis of Functional Neuroimages software. Region of interest (ROI based analysis was performed to study changes in the sensorimotor network using pre- and post-central gyri as seed regions. Two-sampled t-test was carried out to check for significant differences between the two groups. SCI patients showed decreased functional connectivity in motor and sensory cortical regions when compared to controls. The decrease was noted in ipsilateral, contralateral, and interhemispheric regions for left and right precentral ROIs. Additionally, the left postcentral ROI demonstrated increased connectivity with the thalamus bilaterally in SCI patients. Our results suggest that cortical activation patterns in the sensorimotor network undergo dynamic reorganization following SCI. The presence of these changes in chronic spinal cord injury patients is suggestive of the inherent neural plasticity within the central nervous system.

  18. A Component-Based Study of the Effect of Diameter on Bond and Anchorage Characteristics of Blind-Bolted Connections.

    Directory of Open Access Journals (Sweden)

    Muhammad Nasir Amin

    Full Text Available Structural hollow sections are gaining worldwide importance due to their structural and architectural advantages over open steel sections. The only obstacle to their use is their connection with other structural members. To overcome the obstacle of tightening the bolt from one side has given birth to the concept of blind bolts. Blind bolts, being the practical solution to the connection hindrance for the use of hollow and concrete filled hollow sections play a vital role. Flowdrill, the Huck High Strength Blind Bolt and the Lindapter Hollobolt are the well-known commercially available blind bolts. Although the development of blind bolts has largely resolved this issue, the use of structural hollow sections remains limited to shear resistance. Therefore, a new modified version of the blind bolt, known as the "Extended Hollo-Bolt" (EHB due to its enhanced capacity for bonding with concrete, can overcome the issue of low moment resistance capacity associated with blind-bolted connections. The load transfer mechanism of this recently developed blind bolt remains unclear, however. This study uses a parametric approach to characterising the EHB, using diameter as the variable parameter. Stiffness and load-carrying capacity were evaluated at two different bolt sizes. To investigate the load transfer mechanism, a component-based study of the bond and anchorage characteristics was performed by breaking down the EHB into its components. The results of the study provide insight into the load transfer mechanism of the blind bolt in question. The proposed component-based model was validated by a spring model, through which the stiffness of the EHB was compared to that of its components combined. The combined stiffness of the components was found to be roughly equivalent to that of the EHB as a whole, validating the use of this component-based approach.

  19. Intramuscular Connective Tissue Differences in Spastic and Control Muscle: A Mechanical and Histological Study

    Science.gov (United States)

    de Bruin, Marije; Smeulders, Mark J.; Kreulen, Michiel; Huijing, Peter A.; Jaspers, Richard T

    2014-01-01

    Cerebral palsy (CP) of the spastic type is a neurological disorder characterized by a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks. Secondary to the spasticity, muscle adaptation is presumed to contribute to limitations in the passive range of joint motion. However, the mechanisms underlying these limitations are unknown. Using biopsies, we compared mechanical as well as histological properties of flexor carpi ulnaris muscle (FCU) from CP patients (n = 29) and healthy controls (n = 10). The sarcomere slack length (mean 2.5 µm, SEM 0.05) and slope of the normalized sarcomere length-tension characteristics of spastic fascicle segments and single myofibre segments were not different from those of control muscle. Fibre type distribution also showed no significant differences. Fibre size was significantly smaller (1933 µm2, SEM 190) in spastic muscle than in controls (2572 µm2, SEM 322). However, our statistical analyses indicate that the latter difference is likely to be explained by age, rather than by the affliction. Quantities of endomysial and perimysial networks within biopsies of control and spastic muscle were unchanged with one exception: a significant thickening of the tertiary perimysium (3-fold), i.e. the connective tissue reinforcement of neurovascular tissues penetrating the muscle. Note that this thickening in tertiary perimysium was shown in the majority of CP patients, however a small number of patients (n = 4 out of 23) did not have this feature. These results are taken as indications that enhanced myofascial loads on FCU is one among several factors contributing in a major way to the aetiology of limitation of movement at the wrist in CP and the characteristic wrist position of such patients. PMID:24977410

  20. Intramuscular connective tissue differences in spastic and control muscle: a mechanical and histological study.

    Directory of Open Access Journals (Sweden)

    Marije de Bruin

    Full Text Available Cerebral palsy (CP of the spastic type is a neurological disorder characterized by a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks. Secondary to the spasticity, muscle adaptation is presumed to contribute to limitations in the passive range of joint motion. However, the mechanisms underlying these limitations are unknown. Using biopsies, we compared mechanical as well as histological properties of flexor carpi ulnaris muscle (FCU from CP patients (n = 29 and healthy controls (n = 10. The sarcomere slack length (mean 2.5 µm, SEM 0.05 and slope of the normalized sarcomere length-tension characteristics of spastic fascicle segments and single myofibre segments were not different from those of control muscle. Fibre type distribution also showed no significant differences. Fibre size was significantly smaller (1933 µm2, SEM 190 in spastic muscle than in controls (2572 µm2, SEM 322. However, our statistical analyses indicate that the latter difference is likely to be explained by age, rather than by the affliction. Quantities of endomysial and perimysial networks within biopsies of control and spastic muscle were unchanged with one exception: a significant thickening of the tertiary perimysium (3-fold, i.e. the connective tissue reinforcement of neurovascular tissues penetrating the muscle. Note that this thickening in tertiary perimysium was shown in the majority of CP patients, however a small number of patients (n = 4 out of 23 did not have this feature. These results are taken as indications that enhanced myofascial loads on FCU is one among several factors contributing in a major way to the aetiology of limitation of movement at the wrist in CP and the characteristic wrist position of such patients.

  1. Intramuscular connective tissue differences in spastic and control muscle: a mechanical and histological study.

    Science.gov (United States)

    de Bruin, Marije; Smeulders, Mark J; Kreulen, Michiel; Huijing, Peter A; Jaspers, Richard T

    2014-01-01

    Cerebral palsy (CP) of the spastic type is a neurological disorder characterized by a velocity-dependent increase in tonic stretch reflexes with exaggerated tendon jerks. Secondary to the spasticity, muscle adaptation is presumed to contribute to limitations in the passive range of joint motion. However, the mechanisms underlying these limitations are unknown. Using biopsies, we compared mechanical as well as histological properties of flexor carpi ulnaris muscle (FCU) from CP patients (n = 29) and healthy controls (n = 10). The sarcomere slack length (mean 2.5 µm, SEM 0.05) and slope of the normalized sarcomere length-tension characteristics of spastic fascicle segments and single myofibre segments were not different from those of control muscle. Fibre type distribution also showed no significant differences. Fibre size was significantly smaller (1933 µm2, SEM 190) in spastic muscle than in controls (2572 µm2, SEM 322). However, our statistical analyses indicate that the latter difference is likely to be explained by age, rather than by the affliction. Quantities of endomysial and perimysial networks within biopsies of control and spastic muscle were unchanged with one exception: a significant thickening of the tertiary perimysium (3-fold), i.e. the connective tissue reinforcement of neurovascular tissues penetrating the muscle. Note that this thickening in tertiary perimysium was shown in the majority of CP patients, however a small number of patients (n = 4 out of 23) did not have this feature. These results are taken as indications that enhanced myofascial loads on FCU is one among several factors contributing in a major way to the aetiology of limitation of movement at the wrist in CP and the characteristic wrist position of such patients.

  2. Pulmonary hypertension not a major feature of early mixed connective tissue disease: A prospective clinicoserological study

    Directory of Open Access Journals (Sweden)

    Haroon N

    2005-01-01

    Full Text Available Background: Mixed connective tissue disease (MCTD has features common to lupus, scleroderma and myositis with high levels of antibodies to U1 ribonucleoprotein (U1 RNP. Identification of a high incidence of pulmonary artery hypertension (PAH has changed its prospect. We report the largest series from India. Settings and Design: Rheumatology unit of a tertiary care centre in India; prospective. Materials and Methods: Patients seen between January 2002 and June 2004, satisfying the Kasukawa criteria were enrolled. All patients had a complete laboratory work-up including pulmonary function test, 2-D echocardiography, and Schirmer′s test, antinuclear antibodies (ANA and antibodies to extractable nuclear antigens. HRCT of chest was done where indicated. All patients were given standard treatment and followed up regularly. Results: Out of 1500 patients, thirteen (one male were diagnosed to have MCTD. The median follow-up period was 18 months [Interquartile range (IQR 12-22]. The median age of onset of symptoms was 36 years (IQR 22-39 and the median duration of disease was three years (IQR 1.75-4. The most common manifestation was polyarthritis followed by puffy fingers. Sjogren′s syndrome, dysphagia and interstitial lung disease, was present in four, three and two patients respectively. Two patients each had myositis and migraine. None had PAH, serositis or renal involvement. Arthritis, puffy fingers and RaynaudÆs phenomenon were the most common manifestations at onset. All patients were positive for ANA and anti U1 RNP. Two patients each had antibodies to Sm and SSA. Response to treatment also was noted. Conclusion: Pulmonary artery hypertension is not common in early MCTD.

  3. External thoracic duct-venous shunt in conscious pigs for long term studies of connective tissue metabolites in lymph

    DEFF Research Database (Denmark)

    Jensen, L T; Olesen, H P; Risteli, J

    1990-01-01

    An experimental animal model for lymph studies is described. Thoracic duct-venous shunt was established in 12 pigs. Shunt patency averaged 5.5 days. The composition of connective tissue metabolites in lymph and serum were investigated during a standardized surgical operation (thoracotomy) under...... is a major route of tissue clearance for these components. The lymph/serum ratio of PICP was 1.0 in conscious pigs, indicating a direct release into the circulation. Total protein in lymph decreased (p less than 0.04) during surgery/anesthesia, whereas no changes were observed in serum. Pigs can be used...

  4. Comparative study of the possibility of interdental papilla reconstruction using connective tissue graft with and without Emdogain

    Directory of Open Access Journals (Sweden)

    Soleymani Shayesteh Y.

    2008-04-01

    Full Text Available Background and Aim: Improving esthetics is a major goal in periodontal treatments and specially reconstruction of dental papilla is of great importance. Different techniques have been developed, however the results are not completely predictable. The aim of the present study was to compare the possibility of papilla reconstruction using connective tissue graft with and without Emdogain.Materials and Methods: In this clinical trial, 40 class II lost interdental papilla (Nordland- Tarnow classification in 18 patients (4 male and 14 female were studied. Samples were randomly devided into two groups. Case group was treated by connective tissue graft and emdogain (Straumann-USA and controls were treated using connective tissue graft only. Periodontal parameters including papilla height (PH, periodontal pocket depth (PPD and clinical attachment level (CAL were measured before surgery, and 3 and 6 months after treatment. At the tenth days and 1 month after treatment only the papilla height was measured. Repeated measures analysis was used for data analysis with p<0.05 as the level of significance.Results: In the control group the mean papilla height changed from 3.38 0.89 to 2.85 0.93 on the 3rd month and 2.90 0.95 on the 6th month. The mean PPD changed from 2.8  0.68 to 2.55 0.70 on the 3rd month and 3.06 1.25 on the 6th month. The mean CAL changed from 3.88 1.29 to 3.79 1.25 on the 3rd month and 4.11 1.44 on the 6th month. In test group the mean papilla height changed from 2.98 0.91 to 2.45 1.55 on the 3rd month and 2.55 1.48 on the 6th month. The mean PPD changed from 2.75 1.49 to 2.63 1.38 on the 3rd month and 2.88 1.39 on the 6th month. The mean CAL changed from 3.75 1.24 to 4.01 1.45 on the 3rd month and 4.28 1.63 on the 6th month. These differences were not significant between the studied groups (P>0.05.Conclusion: Based on the results of this study, use of connective tissue with or without emdogain is not effective in interdental papilla

  5. Cortical and subcortical connectivity changes during decreasing levels of consciousness in humans: a functional magnetic resonance imaging study using propofol.

    Science.gov (United States)

    Mhuircheartaigh, Róisín Ní; Rosenorn-Lanng, Debbie; Wise, Richard; Jbabdi, Saad; Rogers, Richard; Tracey, Irene

    2010-07-07

    While ubiquitous, pharmacological manipulation of consciousness remains poorly defined and incompletely understood (Prys-Roberts, 1987). This retards anesthetic drug development, confounds interpretation of animal studies conducted under anesthesia, and limits the sensitivity of clinical monitors of cerebral function to intact perception. Animal and human studies propose a functional "switch" at the level of the thalamus, with inhibition of thalamo-cortical transmission characterizing loss of consciousness (Alkire et al., 2000; Mashour, 2006). We investigated the effects of propofol, widely used for anesthesia and sedation, on spontaneous and evoked cerebral activity using functional magnetic resonance imaging (fMRI). A series of auditory and noxious stimuli was presented to eight healthy volunteers at three behavioral states: awake, "sedated" and "unresponsive." Performance in a verbal task and the absence of a response to verbal stimulation, rather than propofol concentrations, were used to define these states clinically. Analysis of stimulus-related blood oxygenation level-dependent signal changes identified reductions in cortical and subcortical responses to auditory and noxious stimuli in sedated and unresponsive states. A specific reduction in activity within the putamen was noted and further investigated with functional connectivity analysis. Progressive failure to perceive or respond to auditory or noxious stimuli was associated with a reduction in the functional connectivity between the putamen and other brain regions, while thalamo-cortical connectivity was relatively preserved. This result has not been previously described and suggests that disruption of subcortical thalamo-regulatory systems may occur before, or even precipitate, failure of thalamo-cortical transmission with the induction of unconsciousness.

  6. Altered Functional Connectivity in Patients with Subcortical Vascular Cognitive Impairment--A Resting-State Functional Magnetic Resonance Imaging Study.

    Directory of Open Access Journals (Sweden)

    Weina Ding

    Full Text Available Recent neuroimaging studies have shown that people with subcortical vascular cognitive impairment (sVCI have structural and functional abnormalities in the frontal lobe and subcortical brain sites. In this study, we used seed-based resting-state functional connectivity (rsFC analysis and voxel-mirrored homotopic connectivity (VMHC techniques to investigate the alteration of rsFC in patients with sVCI. rsFC and structural magnetic resonance images were acquired for 51 patients with subcortical cerebrovascular disease. All patients were subdivided based on cognitive status into 29 with sVCI and 22 controls; patient characteristics were matched. rsFC of the posterior cingulate cortex (PCC and VMHC were calculated separately, and rsFC of the PCC and VMHC between the two groups were compared. The regions showing abnormal rsFC of the PCC or VMHC in sVCI patients were adopted as regions of interest for correlation analyses. Our results are as follows: The patients with sVCI exhibited increases in rsFC in the left middle temporal lobe, right inferior temporal lobe and left superior frontal gyrus, and significant decreases in rsFC of the left thalamus with the PCC. sVCI patients showed a significant deficit in VMHC between the bilateral lingual gyrus, putamen, and precentral gyrus. Additionally, the z-memory score was significantly positively associated with connectivity between the left thalamus and the PCC (r = 0.41, p = 0.03, uncorrected in the sVCI group. Our findings suggest that the frontal lobe and subcortical brain sites play an important role in the pathogenesis of sVCI. Furthermore, rsFC between the left thalamus and the PCC might indicate the severity of sVCI.

  7. Marginal bone and soft tissue behavior following platform switching abutment connection/disconnection--a dog model study.

    Science.gov (United States)

    Alves, Célia C; Muñoz, Fernando; Cantalapiedra, António; Ramos, Isabel; Neves, Manuel; Blanco, Juan

    2015-09-01

    The effect on the marginal peri-implant tissues following repeated platform switching abutment removal and subsequent reconnection was studied. Six adult female Beagle dogs were selected, and Pm3 and Pm4 teeth, both left and right sides, were extracted and the sites healed for 3 months. At this time, 24 bone level (BL) (Straumann, Basel, Switzerland) Ø 3.3/8 mm implants were placed, 2 in each side on Pm3 and Pm4 regions. In one side (control group), 12 bone level conical Ø 3.6 mm healing abutments and, on the other side (test group), 12 Narrow CrossFit (NC) multibase abutments (Straumann) , Basel, Switzerland) were connected at time of implant surgery. On test group, all prosthetic procedures were carried out direct to multibase abutment without disconnecting it, where in the control group, the multibase abutment was connected/disconnected five times (at 6/8/10/12/14 weeks) during prosthetic procedures. Twelve fixed metal bridges were delivered 14 weeks after implant placement. A cleaning/control appointment was scheduled 6 months after implant placement. The animals were sacrificed at 9 months of the study. Clinical parameters and peri-apical x-rays were registered in every visit. Histomorphometric analysis was carried out for the 24 implants. The distance from multibase abutment shoulder to the first bone implant contact (S-BIC) was defined as the primary histomorphometric parameter. Wilcoxon comparison paired test (n = 6) found no statistically significant differences (buccal P = 0.917; Lingual P = 0.463) between test and control groups both lingually and buccally for S-BIC distance. Only Pm3 buccal aBE-BC (distance from the apical end of the barrier epithelium to the first bone implant contact) (P = 0.046) parameter presented statistically significant differences between test and control groups. Control group presented 0.57 mm more recession than test group, being this difference statistically significant between the two groups (P < 0.001). It can be conclude

  8. ‘Piling on layers of understanding’: the use of connective ethnography for the study of (online) work practices

    NARCIS (Netherlands)

    V. Dirksen; A. Huizing; B. Smit

    2010-01-01

    This article explores the notion of connective ethnography as a modern form of ethnography. In the concept of connective ethnography presented in this article, the sensitivity to ‘the making of context’ includes both the sense of a local physical context as well as the increasing connections between

  9. Performance Comparison Study of Connected Dominating Set Algorithms for Mobile Ad hoc Networks under Different Mobility Models

    Directory of Open Access Journals (Sweden)

    Natarajan Meghanathan

    2013-05-01

    Full Text Available The high-level contribution of this paper is an exhaustive simulation-based comparison study of three categories (density, node id and stability-based of algorithms to determine connected dominating sets (CDS for mobile ad hoc networks and evaluate their performance under two categories (random node mobility and grid-based vehicular ad hoc network of mobility models. The CDS algorithms studied are the maximum density-based (MaxD-CDS, node ID-based (ID-CDS and the minimum velocity-based (MinV-CDS algorithms representing the density, node id and stability categories respectively. The node mobility models used are the Random Waypoint model (representing random node mobility and the City Section and Manhattan mobility models (representing the grid-based vehicular ad hoc networks. The three CDS algorithms under the three mobility models are evaluated with respect to two critical performance metrics: the effective CDS lifetime (calculated taking into consideration the CDS connectivity and absolute CDS lifetime and the CDS node size. Simulations are conducted under a diverse set of conditions representing low, moderate and high network density, coupled with low, moderate and high node mobility scenarios. For each CDS, the paper identifies the mobility model that can be employed to simultaneously maximize the lifetime and minimize the node size with minimal tradeoff. For the two VANET mobility models, the impact of the grid block length on the CDS lifetime and node size is also evaluated.

  10. Takotsubo syndrome – A close connection to the brain: A prospective study investigating neuropsychiatric traits

    Directory of Open Access Journals (Sweden)

    Kristina N. Mayer

    2016-09-01

    Conclusion: The study highlights a high prevalence of psychiatric and neurologic comorbidities in patients with TTS, which so far have been under-diagnosed. Future studies will have to show whether these patients might benefit from a combined psychocardiologic rehabilitation.

  11. Singularities of invariant connections

    Energy Technology Data Exchange (ETDEWEB)

    Amores, A.M. (Universidad Complutense, Madrid (Spain)); Gutierrez, M. (Universidad Politecnica, Madrid (Spain))

    1992-12-01

    A reductive homogeneous space M = P/G is considered, endowed with an invariant connection, i.e., such that all left translations of M induced by members of P preserve it. The authors study the set of singularities of such connections giving sufficient conditions for it to be empty, or, in other cases, familities of b-incomplete curves converging to singularities. A full description of the b-completion of a connection with M = R[sup m] (or a quotient of it) is given with information on its topology. 5 refs.

  12. Humans as (dis)connecting agents in fluvial systems: a conceptualization with case studies from small to meso-scale catchments

    Science.gov (United States)

    Poeppl, R. E.; Keesstra, S. D.; Fuchs, S.; Seeger, M.; Bertsch, R.; Glade, T.

    2012-04-01

    Knowledge about connectivity relationships in fluvial systems is of major importance, especially for assessing geomorphic system response to human interference. In the field of geomorphology, previous connectivity concepts have primarily focused on the (dis)connecting effects of different landscape forms rather than considering the role of humans. The authors will introduce a conceptual model highlighting the importance of humans as (dis)connecting agents in fluvial systems. It will be further demonstrated that different spatial dimensions of connectivity are interrelated, since alterations in one distinct spatial dimension cause changes in another. The reflections are underpinned by presenting case study examples from small (1 - 10 km2) to meso-scale catchments (10 - 1,000 km2) in different environmental settings. Direct as well as indirect human impacts on fluvial systems lead to significant changes in different spatial dimensions of connectivity, consequently inducing geomorphic changes. The construction of dams, for example, leads to a significant reduction of connectivity in longitudinal direction which is followed by river bed erosion downstream of the dam. Lateral connectivity relationships are modified by major land use changes in the catchments, hence altering the river runoff and sediment dynamics. In this context, reforestation, for example, leads to channel narrowing as a result of lower peak flows and a decrease of lateral sediment input. Another case study example shows how gully development is influenced by the construction of dirt roads, since these features are altering flow routing and hence connectivity within the gully catchment. Moreover, an example will be presented demonstrating that connectivity relationships in fluvial systems also change with time due to self-organizing properties of the system.

  13. Functional connectivity in the first year of life in infants at-risk for autism: A preliminary near-infrared spectroscopy study

    Directory of Open Access Journals (Sweden)

    Brandon eKeehn

    2013-08-01

    Full Text Available Background: Autism spectrum disorder (ASD has been called a ‘developmental disconnection syndrome,’ however the majority of the research examining connectivity in ASD has been conducted exclusively with older children and adults. Yet, prior ASD research suggests that perturbations in neurodevelopmental trajectories begin as early as the first year of life. Prospective longitudinal studies of infants at risk for ASD may provide a window into the emergence of these aberrant patterns of connectivity. The current study employed functional connectivity near-infrared spectroscopy (NIRS in order to examine the development of intra- and inter-hemispheric functional connectivity in high- and low-risk infants across the first year of life.Methods: NIRS data were collected from 27 infants at high risk for autism (HRA and 37 low-risk comparison (LRC infants who contributed a total of 116 data sets at 3-, 6-, 9-, and 12-months. At each time point, HRA and LRC groups were matched on age, sex, head circumference, and Mullen Scales of Early Learning scores. Regions of interest (ROI were selected from anterior and posterior locations of each hemisphere. The average time course for each ROI was calculated and correlations for each ROI pair were computed. Differences in functional connectivity were examined in a cross-sectional manner.Results: At 3-months, HRA infants showed increased overall functional connectivity compared to LRC infants. This was the result of increased connectivity for intra- and inter-hemispheric ROI pairs. No significant differences were found between HRA and LRC infants at 6- and 9-months. However, by 12-months, HRA infants showed decreased connectivity relative to LRC infants.Conclusions: Our preliminary results suggest that atypical functional connectivity may exist within the first year of life in HRA infants, providing support to the growing body of evidence that aberrant patterns of connectivity may be a potential endophenotype for

  14. Devaluation, Diffusion and the College Connection: A Study of High School Transcripts, 1964-1981.

    Science.gov (United States)

    Adelman, Clifford

    This paper reanalyzed existing transcript data from: (1) the Study of Academic Prediction and Growth (High School Class of 1969) ; and (2) the New Youth Cohort of the National Longitudinal Study of Labor Market Experience (High School Classes of 1975-1981) in terms of various measures of the quantity of schooling, and in relation to changes in…

  15. Connecting the disconnected: Background, practices and motives of labour brokers in Isan, Thailand - An explorative study

    NARCIS (Netherlands)

    Chamaratana, T.; Ayuwat, D.; Knippenberg, L.W.J.; Jong, E.B.P. de

    2010-01-01

    International labour migration is one of the major issues of our time. Nowadays around 192 million people work outside their country of birth, about three percent of the world’s population. This rapidly increasing phenomenon is examined in a large number of studies on migration. Most of these studie

  16. The connecting health and technology study: a 6-month randomized controlled trial to improve nutrition behaviours using a mobile food record and text messaging support in young adults

    National Research Council Canada - National Science Library

    Kerr, Deborah A; Harray, Amelia J; Pollard, Christina M; Dhaliwal, Satvinder S; Delp, Edward J; Howat, Peter A; Pickering, Mark R; Ahmad, Ziad; Meng, Xingqiong; Pratt, Iain S; Wright, Janine L; Kerr, Katherine R; Boushey, Carol J

    2016-01-01

    .... The Connecting Health and Technology study aimed to evaluate the effectiveness of tailored dietary feedback and weekly text messaging to improve dietary intake of fruit, vegetables and junk food over...

  17. Quantifying bicycle network connectivity.

    Science.gov (United States)

    Lowry, Michael; Loh, Tracy Hadden

    2017-02-01

    The intent of this study was to compare bicycle network connectivity for different types of bicyclists and different neighborhoods. Connectivity was defined as the ability to reach important destinations, such as grocery stores, banks, and elementary schools, via pathways or roads with low vehicle volumes and low speed limits. The analysis was conducted for 28 neighborhoods in Seattle, Washington under existing conditions and for a proposed bicycle master plan, which when complete will provide over 700 new bicycle facilities, including protected bike lanes, neighborhood greenways, and multi-use trails. The results showed different levels of connectivity across neighborhoods and for different types of bicyclists. Certain projects were shown to improve connectivity differently for confident and non-confident bicyclists. The analysis showed a positive correlation between connectivity and observed utilitarian bicycle trips. To improve connectivity for the majority of bicyclists, planners and policy-makers should provide bicycle facilities that allow immediate, low-stress access to the street network, such as neighborhood greenways. The analysis also suggests that policies and programs that build confidence for bicycling could greatly increase connectivity.

  18. Family-based case-control study of homotopic connectivity in first-episode, drug-naive schizophrenia at rest

    Science.gov (United States)

    Guo, Wenbin; Liu, Feng; Chen, Jindong; Wu, Renrong; Li, Lehua; Zhang, Zhikun; Zhao, Jingping

    2017-01-01

    Family-based case-control design is rarely used but powerful to reduce the confounding effects of environmental factors on schizophrenia. Twenty-eight first-episode, drug-naive patients with schizophrenia, 28 family-based controls (FBC), and 40 healthy controls (HC) underwent resting-state functional MRI. Voxel-mirrored homotopic connectivity (VMHC), receiver operating characteristic curve (ROC), and support vector machine (SVM) were used to process the data. Compared with the FBC, the patients showed lower VMHC in the precuneus, fusiform gyrus/cerebellum lobule VI, and lingual gyrus/cerebellum lobule VI. The patients exhibited lower VMHC in the precuneus relative to the HC. ROC analysis exhibited that the VMHC values in these brain regions might not be ideal biomarkers to distinguish the patients from the FBC/HC. However, SVM analysis indicated that a combination of VMHC values in the precuneus and lingual gyrus/cerebellum lobule VI might be used as a potential biomarker to distinguish the patients from the FBC with a sensitivity of 96.43%, a specificity of 89.29%, and an accuracy of 92.86%. Results suggested that patients with schizophrenia have decreased homotopic connectivity in the motor and low level sensory processing regions. Neuroimaging studies can adopt family-based case-control design as a viable option to reduce the confounding effects of environmental factors on schizophrenia. PMID:28256527

  19. Atlasing the frontal lobe connections and their variability due to age and education: a spherical deconvolution tractography study.

    Science.gov (United States)

    Rojkova, K; Volle, E; Urbanski, M; Humbert, F; Dell'Acqua, F; Thiebaut de Schotten, M

    2016-04-01

    In neuroscience, there is a growing consensus that higher cognitive functions may be supported by distributed networks involving different cerebral regions, rather than by single brain areas. Communication within these networks is mediated by white matter tracts and is particularly prominent in the frontal lobes for the control and integration of information. However, the detailed mapping of frontal connections remains incomplete, albeit crucial to an increased understanding of these cognitive functions. Based on 47 high-resolution diffusion-weighted imaging datasets (age range 22-71 years), we built a statistical normative atlas of the frontal lobe connections in stereotaxic space, using state-of-the-art spherical deconvolution tractography. We dissected 55 tracts including U-shaped fibers. We further characterized these tracts by measuring their correlation with age and education level. We reported age-related differences in the microstructural organization of several, specific frontal fiber tracts, but found no correlation with education level. Future voxel-based analyses, such as voxel-based morphometry or tract-based spatial statistics studies, may benefit from our atlas by identifying the tracts and networks involved in frontal functions. Our atlas will also build the capacity of clinicians to further understand the mechanisms involved in brain recovery and plasticity, as well as assist clinicians in the diagnosis of disconnection or abnormality within specific tracts of individual patients with various brain diseases.

  20. Parcel-based connectivity analysis of fMRI data for the study of epileptic seizure propagation.

    Science.gov (United States)

    Tana, Maria Gabriella; Bianchi, Anna Maria; Sclocco, Roberta; Franchin, Tiziana; Cerutti, Sergio; Leal, Alberto

    2012-10-01

    The aim of this work is to improve fMRI Granger Causality Analysis (GCA) by proposing and comparing two strategies for defining the topology of the networks among which cerebral connectivity is measured and to apply fMRI GCA for studying epileptic seizure propagation. The first proposed method is based on information derived from anatomical atlas only; the other one is based on functional information and employs an algorithm of hierarchical clustering applied to fMRI data directly. Both methods were applied to signals recorded during seizures on a group of epileptic subjects and two connectivity matrices were obtained for each patient. The performances of the different parcellation strategies were evaluated in terms of their capability to recover information about the source and the sink of the network (i.e., the starting and the ending point of the seizure propagation). The first method allows to clearly identify the seizure onset in all patients, whereas the network sources are not so immediately recognizable when the second method was used. Nevertheless, results obtained using functional clustering do not contradict those obtained with the anatomical atlas and are able to individuate the main pattern of propagation. In conclusion, the way nodes are defined can influence the easiness of identification of the epileptogenic focus but does not produce contradictory results showing the effectiveness of proposed approach to formulate hypothesis about seizure propagation at least in the early phase of investigation.

  1. Functional connectivity associated with social networks in older adults: A resting-state fMRI study.

    Science.gov (United States)

    Pillemer, Sarah; Holtzer, Roee; Blumen, Helena M

    2017-06-01

    Poor social networks and decreased levels of social support are associated with worse mood, health, and cognition in younger and older adults. Yet, we know very little about the brain substrates associated with social networks and social support, particularly in older adults. This study examined functional brain substrates associated with social networks using the Social Network Index (SNI) and resting-state functional magnetic resonance imaging (fMRI). Resting-state fMRI data from 28 non-demented older adults were analyzed with independent components analyses. As expected, four established resting-state networks-previously linked to motor, vision, speech, and other language functions-correlated with the quality (SNI-1: total number of high-contact roles of a respondent) and quantity (SNI-2: total number of individuals in a respondent's social network) of social networks: a sensorimotor, a visual, a vestibular/insular, and a left frontoparietal network. Moreover, SNI-1 was associated with greater functional connectivity in the lateral prefrontal regions of the left frontoparietal network, while SNI-2 was associated with greater functional connectivity in the medial prefrontal regions of this network. Thus, lateral prefrontal regions may be particularly linked to the quality of social networks while medial prefrontal regions may be particularly linked to the quantity of social networks.

  2. Historical connection between memory and testimony psychology by an experimental study of Seiichi Terada in Japan

    National Research Council Canada - National Science Library

    Wakabayashi, Kosuke; Sato, Tatsuya

    2012-01-01

    .... This is probably the first experimental study of law and psychology carried out in Japan. This article introduces Terada's history as a psychologist, and his collaboration with Makino, followed by explanation of their experiments...

  3. Clinical evaluation of subepithelial connective tissue graft and guided tissue regeneration for treatment of Miller's class 1 gingival recession: comparative, split mouth, six months study

    OpenAIRE

    Trivedi, Sakshee R.; Bhavsar, Neeta V.; Dulani, Kirti; Trivedi, Rahul

    2014-01-01

    Objectives: The present study aims to clinically compare and evaluate subepithelial connective tissue graft and the GTR based root coverage in treatment of Miller’s Class I gingival recession. Study Design: 30 patients with at least one pair of Miller’s Class I gingival recession were treated either with Subepithelial connective tissue graft (Group A) or Guided tissue regeneration (Group B). Clinical parameters monitored included recession RD, width of keratinized gingiva (KG), probing depth ...

  4. Effect of street connectivity and density on adult BMI: results from the Twin Cities Walking Study.

    Science.gov (United States)

    McDonald, Kelsey N; Oakes, J Michael; Forsyth, Ann

    2012-07-01

    The prevalence of overweight and obesity in the US population has risen dramatically in recent years. To try to explain this, some studies have examined the association between the built environment and obesity (measured using the body mass index (BMI)). Most of these studies have not sought to identify causal effects, but rather correlations. Data from the Twin Cities Walking Study were used to examine the effect of population density and block size on BMI. Although the Twin Cities Walking Study is a cross-sectional observational study, the matched-sampling design is novel in that it maximises environmental variance while minimising person variance to enhance exchangeability of subjects and more closely mimic an experimental study. Contrary to expectations, the hypothesised most walkable neighbourhood (high density, small block stratum) had the greatest mean and median BMI. After adjusting for demographic covariates, physical activity and clustering due to neighbourhood, no conclusive effect of population density by block size on BMI was found (β=-1.024, 95% CI -2.408 to 0.359). There is no evidence of an effect of population density by block size on BMI.

  5. A multicenter study of the early detection of synaptic dysfunction in Mild Cognitive Impairment using Magnetoencephalography-derived functional connectivity.

    Science.gov (United States)

    Maestú, Fernando; Peña, Jose-Maria; Garcés, Pilar; González, Santiago; Bajo, Ricardo; Bagic, Anto; Cuesta, Pablo; Funke, Michael; Mäkelä, Jyrki P; Menasalvas, Ernestina; Nakamura, Akinori; Parkkonen, Lauri; López, Maria E; Del Pozo, Francisco; Sudre, Gustavo; Zamrini, Edward; Pekkonen, Eero; Henson, Richard N; Becker, James T

    2015-01-01

    Synaptic disruption is an early pathological sign of the neurodegeneration of Dementia of the Alzheimer's type (DAT). The changes in network synchronization are evident in patients with Mild Cognitive Impairment (MCI) at the group level, but there are very few Magnetoencephalography (MEG) studies regarding discrimination at the individual level. In an international multicenter study, we used MEG and functional connectivity metrics to discriminate MCI from normal aging at the individual person level. A labeled sample of features (links) that distinguished MCI patients from controls in a training dataset was used to classify MCI subjects in two testing datasets from four other MEG centers. We identified a pattern of neuronal hypersynchronization in MCI, in which the features that best discriminated MCI were fronto-parietal and interhemispheric links. The hypersynchronization pattern found in the MCI patients was stable across the five different centers, and may be considered an early sign of synaptic disruption and a possible preclinical biomarker for MCI/DAT.

  6. Evidence from a rare case-study for Hebbian-like changes in structural connectivity induced by long-term deep brain stimulation

    Directory of Open Access Journals (Sweden)

    Tim J Van Hartevelt

    2015-06-01

    Full Text Available It is unclear whether Hebbian-like learning occurs at the level of long-range white matter connections in humans, i.e. where measurable changes in structural connectivity are correlated with changes in functional connectivity. However, the behavioral changes observed after deep brain stimulation (DBS suggest the existence of such Hebbian-like mechanisms occurring at the structural level with functional consequences. In this rare case study, we obtained the full network of white matter connections of one patient with Parkinson's disease before and after long-term DBS and combined it with a computational model of ongoing activity to investigate the effects of DBS-induced long-term structural changes. The results show that the long-term effects of DBS on resting-state functional connectivity is best obtained in the computational model by changing the structural weights from the subthalamic nucleus to the putamen and the thalamus in a Hebbian-like manner. Moreover, long-term DBS also significantly changed the structural connectivity towards normality in terms of model-based measures of segregation and integration of information processing, two key concepts of brain organization. This novel approach using computational models to model the effects of Hebbian-like changes in structural connectivity allowed us to causally identify the possible underlying neural mechanisms of long-term DBS using rare case study data. In time, this could help predict the efficacy of individual DBS targeting and identify novel DBS targets.

  7. How Specific Is the Connection between Morphological Awareness and Spelling? A Study of French Children

    Science.gov (United States)

    Casalis, S.; Deacon, S. H.; Pacton, S.

    2011-01-01

    This study examined the relationship between morphological awareness and spelling. We show that French children in Grades 3 and 4 appear to use morphological information in spelling; spelling of sounds for which there are several alternatives was more accurate in derived than in nonderived words. The link between morphological awareness and…

  8. Preservice Teachers Map Compassion: Connecting Social Studies and Literacy through Nonfictional Animal Stories

    Science.gov (United States)

    Rule, Audrey C.; Montgomery, Sarah E.; Vander Zanden, Sarah M.

    2014-01-01

    Nonfiction stories of animal compassion were used in this literacy-social studies integrated lesson to address both efferent and aesthetic stances in transmediation of text from picture books to maps. Preservice early childhood and elementary teachers chose places from the nine recent children's stories, symbolizing them on a map while…

  9. Motor network disruption in essential tremor : a functional and effective connectivity study

    NARCIS (Netherlands)

    Buijink, Arthur W. G.; van der Stouwe, A. M. Madelein; Broersma, Marja; Sharifi, Sarvi; Groot, Paul F. C.; Speelman, Johannes D.; Maurits, Natasha M.; van Rootselaar, Anne-Fleur

    2015-01-01

    Although involvement of the cerebello-thalamo-cortical network has often been suggested in essential tremor, the source of oscillatory activity remains largely unknown. To elucidate mechanisms of tremor generation, it is of crucial importance to study the dynamics within the

  10. Convergent Evolution in the Interest of Integrative Problem Solving: Connecting the Policy Sciences and Interdisciplinary Studies

    Science.gov (United States)

    Wallace, Richard L.; Clark, Susan G.

    2014-01-01

    The contemporary fields of interdisciplinary studies and the policy sciences have evolved over similar intellectual paths and timelines, beginning in the early 20th century. Both have their roots in professional efforts--within and outside the academy--to address numerous, growing, and complex problems that face humanity. The policy sciences'…

  11. Connecting Children to Nature: A Multiple Case Study of Nature Center Preschools

    Science.gov (United States)

    Bailie, Patti Ensel

    2012-01-01

    Environmental degradation, childhood obesity, and aggression of youth are societal problems that appear unconnected. However, their cause (and possible solution) may be linked to a common experience--the amount and quality of time spent in the natural world. Environment based education, significant life experience research, and studies involving…

  12. School Finance and Technology: A Case Study Using Grid and Group Theory to Explore the Connections

    Science.gov (United States)

    Case, Stephoni; Harris, Edward L.

    2014-01-01

    Using grid and group theory (Douglas 1982, 2011), the study described in this article examined the intersections of technology and school finance in four schools located in districts differing in size, wealth, and commitment to technology integration. In grid and group theory, grid refers to the degree to which policies and role prescriptions…

  13. A Correlational Study of Building Principal Emotional Intelligence and the Connection to Academic Achievement

    Science.gov (United States)

    Fish, James

    2012-01-01

    While student achievement is only one indicator of a building principal's effectiveness, it is widely considered to be one of the most important. This is especially true in regard to the current climate of accountability surrounding education. Multiple studies have yielded results concerning the behaviors and characteristics of building…

  14. Education for connecting Omani students with other cultures in the world: The role of social studies

    Science.gov (United States)

    Al-Maamari, Saif

    2016-08-01

    Oman is a multicultural society in terms of both ethnicity and religion. Communities vary in terms of cultural heritage, language, dress and religious or sectarian affiliation. The majority of people are Arab; other members of society belong to one of three main ethnic groups: the Hyderabadi, the Baluchis or the Zanzibari (Arabs of Omani descent who lived in Zanzibar for many years and returned to Oman after 1970). Arabic is considered the official language in Oman; however, several other languages such as English, Urdu, Baluchi and Swahili are also spoken. Islam is the state religion of the sultanate, with the majority of people being Ibadhi while the remaining population is divided between the Sunni and the Shi'a denominations. This cultural and religious diversity needs to be reflected in the school curriculum, especially in Social Studies education, which is regarded as the subject closest to intercultural education in terms of concepts, skills and values. This paper is based on a literature review exploring current practices regarding intercultural education in Omani schools. Specifically, the study attempts to identify which practices are implemented by Omani schools to help Omani students develop positive attitudes towards differences among cultures. The author considers both curricular and extra-curricular elements of intercultural education. He then turns to Social Studies textbooks used in Omani schools, investigating unit contents. His conclusion is that while intercultural education is to some extent already incorporated in the Omani education system, current practices are far from sufficient. There is still a great need to improve teacher training and open up the Social Studies curriculum considerably to include all the students' cultures and faiths.

  15. Childhood maltreatment and amygdala connectivity in methamphetamine dependence: a pilot study

    OpenAIRE

    Dean, Andy C.; Kohno, Milky; Hellemann, Gerhard; London, Edythe D

    2014-01-01

    Introduction Childhood maltreatment, a well-known risk factor for the development of substance abuse disorders, is associated with functional and structural abnormalities in the adult brain, particularly in the limbic system. However, almost no research has examined the relationship between childhood maltreatment and brain function in individuals with drug abuse disorders. Methods We conducted a pilot study of the relationship between childhood maltreatment (evaluated with the Childhood Traum...

  16. Changes in behavioural responses to infrastructure affect local and regional connectivity – a simulation study on pond breeding amphibians

    Directory of Open Access Journals (Sweden)

    Maj-Britt Pontoppidan

    2013-11-01

    Full Text Available An extensive and expanding infrastructural network destroys and fragments natural habitat and has detrimental effect on abundance and population viability of many amphibian species. Roads function as barriers in the landscape. They separate local populations from each other or prevent access to necessary resources. Therefore, road density and traffic intensity in a region may have severe impact on regional as well as local connectivity. Amphibians may be able to detect and avoid unsuitable habitat. Individuals’ ability to avoid roads can reduce road mortality but at the same time road avoidance behaviour, can increase the barrier effect of the road and reduce connectivity. We use an individual based model to explore how changes in road mortality and road avoidance behaviour affect local and regional connectivity in a population of Moor frogs (Rana arvalis. The results indicate that road mortality has a strong negative effect on regional connectivity, but only a small effect on local connectivity. Regional connectivity is positively affected by road avoidance and the effect becomes more pronounced as road mortality decreases. Road avoidance also has a positive effect on local connectivity. When road avoidance is total and the road functions as a 100% barrier regional connectivity is close to zero, while local connectivity exhibit very elevated values. The results suggest that roads may affect not only regional or metapopulation dynamics but also have a direct effect on local population dynamics.

  17. Study of connectivity in student teams by observation of their learning processes

    Science.gov (United States)

    Pacheco, Patricio H.; Correa, Rafael D.

    2016-05-01

    A registration procedure based data tracking classroom activities students formed into teams, which are immersed in basic learning processes, particularly physical sciences is presented. For the analysis of the data various mathematical tools to deliver results in numerical indicators linking their learning, performance, quality of relational nexus to transformation their emotions. The range of variables under observation and further study, which is influenced by the evolution of the emotions of the different teams of students, it also covers the traditional approach to information delivery from outside (teaching in lecture) or from inside each team (abilities of pupils) to instructional materials that enhance learning inquiry and persuasion.

  18. Experimental study of thermal crisis in connection with Tokamak reactor high heat flux components

    Science.gov (United States)

    Gallo, D.; Giardina, M.; Castiglia, F.; Celata, G. P.; Mariani, A.; Zummo, G.; Cumo, M.

    2000-04-01

    The results of an experimental research on high heat flux thermal crisis in forced convective subcooled water flow, under operative conditions of interest to the thermal-hydraulic design of TOKAMAK fusion reactors, are here reported. These experiments, carried out in the framework of a collaboration between the Nuclear Engineering Department of Palermo University and the National Institute of Thermal - Fluid Dynamics of the ENEA - Casaccia (Rome), were performed on the STAF (Scambio Termico Alti Flussi) water loop and consisted, essentially, in a high speed photographic study which enabled focusing several information on bubble characteristics and flow patterns taking place during the burnout phenomenology.

  19. Decomposition studies of no-clean solder flux systems in connection with corrosion reliability of electronics

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Verdingovas, Vadimas

    2013-01-01

    One of the predominant factors for accelerated corrosion in electronics is the intrinsic contamination on Printed Circuit Board Assemblies (PCBAs) originating from the soldering process used for component mounting. However, the amount, distribution, and morphology of flux residue vary considerably...... such as electrochemical migration resulting in intermittent or permanent failures. This paper summarizes the investigations on decomposition of some typical no-clean flux systems (WOA based) which are used today for the electronic manufacturing. The change in flux chemistry was studied as a function of temperature...

  20. A DCM study of spectral asymmetries in feedforward and feedback connections between visual areas V1 and V4 in the monkey.

    Science.gov (United States)

    Bastos, A M; Litvak, V; Moran, R; Bosman, C A; Fries, P; Friston, K J

    2015-03-01

    This paper reports a dynamic causal modeling study of electrocorticographic (ECoG) data that addresses functional asymmetries between forward and backward connections in the visual cortical hierarchy. Specifically, we ask whether forward connections employ gamma-band frequencies, while backward connections preferentially use lower (beta-band) frequencies. We addressed this question by modeling empirical cross spectra using a neural mass model equipped with superficial and deep pyramidal cell populations-that model the source of forward and backward connections, respectively. This enabled us to reconstruct the transfer functions and associated spectra of specific subpopulations within cortical sources. We first established that Bayesian model comparison was able to discriminate between forward and backward connections, defined in terms of their cells of origin. We then confirmed that model selection was able to identify extrastriate (V4) sources as being hierarchically higher than early visual (V1) sources. Finally, an examination of the auto spectra and transfer functions associated with superficial and deep pyramidal cells confirmed that forward connections employed predominantly higher (gamma) frequencies, while backward connections were mediated by lower (alpha/beta) frequencies. We discuss these findings in relation to current views about alpha, beta, and gamma oscillations and predictive coding in the brain.

  1. Schizophrenia and periodontal disease: An oro-neural connection? A cross-sectional epidemiological study

    Directory of Open Access Journals (Sweden)

    Shreya Shetty

    2014-01-01

    Full Text Available Background: Schizophrenia is a psychosis characterized by delusions and hallucinations occurring in clear consciousness. Studies have shown that the cytokines may modulate dopaminergic metabolism and schizophrenic symptomatology in schizophrenia. Cytokine involvement in periodontal disease is also well documented. To date, however, there has been relatively little research assessing periodontal status of patients with schizophrenia. The present study was therefore mainly intended to understand the exact link, if any, between periodontal disease and schizophrenia. Materials and Methods: A total of 250 schizophrenic patients (140 males and 110 females, between 25 and 55 years of age, were selected from the out patient department of National Institute of Mental Health and Neural Sciences, Bangalore and their periodontal status was assessed as part of this cross-sectional epidemiological survey. Results: ANOVA showed that there was increased evidence of poor periodontal condition, as evidenced by gingival index and plaque index in patients who had been schizophrenic for a longer duration of time (P < 0.001. So also, higher probing pocket depths were found in schizophrenics suffering from a longer period of time than others (P < 0.001. Conclusions: Although oral neglect might be a cause of poor periodontal health in schizophrenics, the possible link between periodontal diseases giving rise to schizophrenia cannot be overlooked due to the presence of cytokine activity which is present both in schizophrenia and periodontal disease.

  2. I FEEL CONNECTED: A COMPARATIVE STUDY OF STUDENT ENGAGEMENT AND LECTURERS’ CREDIBILITY

    Directory of Open Access Journals (Sweden)

    Padma Pillai

    2016-12-01

    Full Text Available Communication is essential. Having the ability to communicate thoughts, ideas, and feelings is crucial in all environments. The education industry regards communication as a core business to transfer knowledge. This paper focuses on how two different groups of students at Sunway University, Malaysia, perceived Lecturers’ Credibility (LC in a class that enhances the Students’ Engagement (SE. A group of 50 to 60 students from the Faculty of Arts (FoA and School of Business (SoB completed measures of LC and SE using McCroskey and Teven’s (1999 Source Credibility Questionnaire (SCQ and Students Engagement Survey from Indicators of Positive Development Conference, Child Trends. The variables for LC comprise competence, character and caring (CCC, and the variables for SE consist of cognitive, behaviour and emotion (CBE. The study aims to determine if there are any differences in SE between students from FoA and SoB with their perceived LC. Hopefully, the study sheds some light on the research question: “Are there any differences among Faculty of Arts students and School of Business students in the relationship between lecturers’ credibility and students’ engagement?”

  3. A probabilistic study of grid-connected wind electric conversion systems

    Science.gov (United States)

    Mohanpurkar, Manish

    Scope and Method of Study. Purpose of the study is to model the power output of Wind Electric Conversion System (WECS) as a random variable given that wind speeds incident on them is random. The model is extended to model probability functions for combined power outputs of multiple WECS located in a wind regime. The impact of variable region in the power characteristic on the probability functions for power output of individual and multiple WECS is investigated. This model is employed in performance assessment of wind farms within probabilistic framework to obtain its load supplying capability. Smart grid functionalities and Demand Side Management (DSM) are identified to have complementary behavior beneficial for optimal operation of electric grid. This is demonstrated using the obtained model for wind farms and a possible modification of load demand distribution function. Findings and Conclusions. The power output of WECS is a mixed random variable. Impact of exponent 'n' on the probability density function (pdf) for power output of multiple WECS is "minor" for a low number of WECS. For a large number of WECS, there occurs a major redistribution of probabilities of power outputs leading to distinct pdf plots for different exponents. Increasing wind penetration leads to flatter power duration curves. Smart grid functionalities and DSM techniques if complemented in a suitable manner will assist in greater assimilation of wind energy into the grid.

  4. Connecting functional and statistical definitions of genotype by genotype interactions in coevolutionary studies

    Directory of Open Access Journals (Sweden)

    Katy Denise Heath

    2014-04-01

    Full Text Available Predicting how species interactions evolve requires that we understand the mechanistic basis of coevolution, and thus the functional genotype-by-genotype interactions (G × G that drive reciprocal natural selection. Theory on host-parasite coevolution provides testable hypotheses for empiricists, but depends upon models of functional G × G that remain loosely tethered to the molecular details of any particular system. In practice, reciprocal cross-infection studies are often used to partition the variation in infection or fitness in a population that is attributable to G × G (statistical G × G. Here we use simulations to demonstrate that within-population statistical G × G likely tells us little about the existence of coevolution, its strength, or the genetic basis of functional G × G. Combined with studies of multiple populations or points in time, mapping and molecular techniques can bridge the gap between natural variation and mechanistic models of coevolution, while model-based statistics can formally confront coevolutionary models with cross-infection data. Together these approaches provide a robust framework for inferring the infection genetics underlying statistical G × G, helping unravel the genetic basis of coevolution.

  5. Techno-economical Analysis of Rooftop Grid-connected PV Dairy Farms; Case Study of Urmia University Dairy Farm

    Science.gov (United States)

    Nikbakht, A. M.; Aste, N.; Sarnavi, H. J.; Leonforte, F.

    2017-08-01

    The global trends indicate a growing commitment to renewable energy development because of declining fossil fuels and environmental threats. Moreover, the global demographic growth coupled with rising demands for food has escalated the rate of energy consumption in food section. This study aims to investigate the techno-economic impacts of a grid-connected rooftop PV plan applied for a educational dairy farm in Urmia university, with total estimated annual electrical energy consumption of 18,283 kWh, located at the north west part of Iran. Based on the current feed-in tariff and tremendously low electricity price in agriculture section in Iran, the plants with size ranged from 14.4 to 19.7 kWp (initial investment ranged from 26,000 to 36,000 USD) would be satisfied economically.

  6. Follow the verbs! A contribution to the study of the Heidegger-Latour connection.

    Science.gov (United States)

    Schiølin, Kasper

    2012-10-01

    Recently, various scholars have attempted to combine the philosophies of Martin Heidegger and Bruno Latour, despite seeming contrasts between them. The present study adds a new perspective to the opening up of this theoretical borderland. In this article, I show how Heidegger's dispute with the philosophical tradition's essentialistic and substantialistic treatment of being, and Latour's dispute with sociology's hypostatisation of the social, share the expression of an epistemological battle against substances, which is most evident in both of their attempts to include technology and things in their thought. Substances are mostly expressed in nouns. Because of this, Heidegger's and Latour's disputes have a grammatical dimension, which in different ways aims to emphasise verbs rather than the nouns in their respective terminology. This grammatical dimension of their shared dispute with substantialism will be demonstrated in this article. I conclude by arguing that Latour's a famous methodological injunction, 'Follow the actors!' can be rewritten as 'Follow the verbs!'.

  7. [Historical connection between memory and testimony psychology by an experimental study of Seiichi Terada in Japan].

    Science.gov (United States)

    Wakabayashi, Kosuke; Sato, Tatsuya

    2012-08-01

    In Japan, Seiichi Terada (1884-1922) was the first psychologist who applied psychological knowledge to the field of law, working in collaboration with the law professor Eiich Makino (1878-1970). Terada's work was mainly in the tradition of clinical psychology, although in his 1915 paper titled "How useful are testimonies?" he described a set of seven experiments concerned with the empirical relationship between eyewitness testimony and memory. This is probably the first experimental study of law and psychology carried out in Japan. This article introduces Terada's history as a psychologist, and his collaboration with Makino, followed by explanation of their experiments. Finally, we discuss perspectives on testimony research in consideration of Terada's approach.

  8. Interdisciplinary island studies: connecting the social sciences, natural sciences and humanities

    Directory of Open Access Journals (Sweden)

    Sietze J. Norder

    2016-11-01

    Full Text Available In this paper, we present the outline of an interdisciplinary undergraduate course entitled: “Islands: Models for our Planet – Metaphors for our World”, and will reflect on insights gained during its development and teaching in two consecutive academic years (2014-2015; 2015-2016. The main challenge faced during the development and teaching of this interdisciplinary course was to introduce a wide range of topics in a coherent way. For this reason, a theoretical framework was developed to guide students throughout their learning process and to structure the content of the course. The developed course materials are shared in the supplementary materials of this paper to facilitate colleagues around the world who are teaching a course in island studies.

  9. The importance of studying the role of establishing discourse connections in the comprehension of expository oral discourse

    Directory of Open Access Journals (Sweden)

    Jazmín Cevasco

    2014-04-01

    Full Text Available The aim of this paper was to highlight the contribution of studies on the comprehension of expository written discourse, and expository and non-expository oral discourse to the facilitation of student learning. It also draws attention to the importance of conducting new studies to explore the role of the variables that facilitate expository written discourse and which have not been investigated in relation to expository oral discourse. Studies that have focused on the design of refutational texts and text revision procedures in the comprehension of expository written discourse are presented, as well as studies on the processing of disfluencies, prosodic cues, causal connections and discourse markers in the comprehension of non-expository oral discourse. Finally, studies on the role of discourse markers, speech rate and metacognitive strategy instruction are presented. It is suggested that these studies can contribute to deciding what revisions to make to written materials in order to improve reading comprehension, and what variables that facilitate the comprehension of expository and non-expository oral discourse to take into account when presenting a lecture.

  10. Connecting a sociology of childhood perspective with the study of child health, illness and wellbeing: introduction.

    Science.gov (United States)

    Brady, Geraldine; Lowe, Pam; Olin Lauritzen, Sonja

    2015-02-01

    In the last decades we have seen a growing interest in research into children's own experiences and understandings of health and illness. This development, we would argue, is much stimulated by the sociology of childhood which has drawn our attention to how children as a social group are placed and perceived within the structure of society, and within inter-generational relations, as well as how children are social agents and co-constructors of their social world. Drawing on this tradition, we here address some cross-cutting themes that we think are important to further the study of child health: situating children within health policy, drawing attention to practices around children's health and well-being and a focus on children as health actors. The paper contributes to a critical analysis of child health policy and notions of child health and normality, pointing to theoretical and empirical research potential for the sociology of children's health and illness. © 2015 The Authors. Sociology of Health & Illness © 2015 Foundation for the Sociology of Health & Illness/John Wiley & Sons Ltd.

  11. Hybrid wind-PV grid connected power station case study: Al Tafila, Jordan

    Energy Technology Data Exchange (ETDEWEB)

    El-Tous, Yousif [Department of Electrical Engineering/Faculty of Engineering Technology/ Al-Balqa' Applied University, Amman, P.O.Box (15008), Marka Ashamalia (Jordan); Al-Battat, Saleh [Department of substation maintenance and protection, National Electric Power Company (NEPCO), Amman (Jordan); Abdel Hafith, Sandro [Department of technical support and project supervision/Integrated power systems co., Amman (Jordan)

    2012-07-01

    In this paper, we are providing an attempt to highlight the importance of renewable energy, more specifically, the one produced from a wind-solar hybrid system. This purpose will be achieved through providing a detailed case study for such system that would be applied in Al-Tafila, Jordan. First and foremost site assessment has been conducted based on an intensive literature review for the data available regarding the availability of wind and solar energy in Jordan and resulted in the selection of Al-Tafila 2 district as the best option among all. Then, the components of the power station and its size have been selected based on specific criteria that make the station as much efficient and competitive as possible. To obtain the output of the different components with respect to the demand for a period of 25 years, a system model was built using HOMER. Finally, the total capital cost of the system was calculated and resulted to be (63400168) $ and with a cost of energy of (0.053) $/kWh which is a very competitive and feasible cost compared to similar international projects and to the conventional energy price.

  12. Hydrogen isotope variability in prairie wetland systems: implications for studies of migratory connectivity.

    Science.gov (United States)

    Bortolotti, Lauren E; Clark, Robert G; Wassenaar, Leonard I

    2013-01-01

    Hydrogen isotopes (delta2H) are often used to infer the origins of migratory animals based on the strong correlation between deuterium content of tissues and long-term patterns of precipitation. However, the extreme flood and drought dynamics of surface waters in prairie wetland systems could mask these expected correlations. We investigated H isotopic variability in an aquatic food web associated with Tree Swallows (Tachycineta bicolor) that rely heavily on wetland-derived aerial insects for food. We evaluated isotopic turnover and incorporation of environmental water into tissue, processes that could affect H isotopic composition. Wetland water and aquatic invertebrates showed intra- and interannual H isotopic variation mainly related to evaporation and the amount and timing of precipitation. Snails showed rapid turnover of tissue deuterium and a large contribution of environmental water to their tissues. Swallow feather deuterium (delta2Hf) was variable but did not clearly follow changes in any of the food web compartments measured. Instead, isotopic variability may have been driven by shifts in the type or relative amounts of grey consumed and types of wetlands used. Nevertheless, despite relatively high variance in delta2Hf, the majority of birds fell within the predicted range of delta2Hf for the study area, revealing that significant trophic averaging occurred. However, both (presumed) diet shifts and variable hydrological conditions have the potential to greatly increase variance that must be considered when assigning origins of migratory animals based on delta2H.

  13. Connecting the person with dementia and family: a feasibility study of a telepresence robot.

    Science.gov (United States)

    Moyle, Wendy; Jones, Cindy; Cooke, Marie; O'Dwyer, Siobhan; Sung, Billy; Drummond, Suzie

    2014-01-24

    Maintenance of communication is important for people with dementia living in long-term care. The purpose of this study was to assess the feasibility of using "Giraff", a telepresence robot to enhance engagement between family and a person with dementia living in long-term care. A mixed-methods approach involving semi-structured interviews, call records and video observational data was used. Five people with dementia and their family member participated in a discussion via the Giraff robot for a minimum of six times over a six-week period. A feasibility framework was used to assess feasibility and included video analysis of emotional response and engagement. Twenty-six calls with an average duration of 23 mins took place. Residents showed a general state of positive emotions across the calls with a high level of engagement and a minimal level of negative emotions. Participants enjoyed the experience and families reported that the Giraff robot offered the opportunity to reduce social isolation. A number of software and hardware challenges were encountered. Participants perceived this novel approach to engage families and people with dementia as a feasible option. Participants were observed and also reported to enjoy the experience. The technical challenges identified have been improved in a newer version of the robot. Future research should include a feasibility trial of longer duration, with a larger sample and a cost analysis.

  14. Hybrid wind-PV grid connected power station case study: Al Tafila, Jordan

    Directory of Open Access Journals (Sweden)

    Yousif El-Tous, Saleh Al-Battat, Sandro Abdel Hafith

    2012-01-01

    Full Text Available In this paper, we are providing an attempt to highlight the importance of renewable energy, more specifically, the one produced from a wind-solar hybrid system. This purpose will be achieved through providing a detailed case study for such system that would be applied in Al-TafilaJordan. First and foremost site assessment has been conducted based on an intensive literature review for the data available regarding the availability of wind and solar energy in Jordan and resulted in the selection of Al-Tafila 2 district as the best option among all. Then, the components of the power station and its size have been selected based on specific criteria that make the station as much efficient and competitive as possible. To obtain the output of the different components with respect to the demand for a period of 25 years, a system model was built using HOMER. Finally, the total capital cost of the system was calculated and resulted to be (63400168 $ and with a cost of energy of (0.053 $/kWh which is a very competitive and feasible cost compared to similar international projects and to the conventional energy price.

  15. Experiment K-7-29: Connective Tissue Studies. Part 1; Rat Skin, Normal and Repair

    Science.gov (United States)

    Vailas, A. C.; Grindeland, R.; Ashman, R.; Choy, V.; Durnova, G.; Graf, B.; Griffith, P.; Kaplansky, A. S.; Kolis, S.; Martinez, D.; Rao, J. S.; Rayford, A. R.; Reddy, B. R.; Sears, J.; Thielke, R.; Ulm, M.; Vanderby, R.

    1994-01-01

    The skin repair studies started to be problematic for the following reasons: (1) It was very difficult to locate the wound and many lesions were not of the same dimensions. A considerable amount of time was devoted to the identification of the wound using polarized light. We understand that this experiment was added on to the overall project. Marking of the wound site and standard dimensions should be recommended for the next flight experiment. (2) The tissue was frozen, therefore thawing and fixation caused problems with some of the immunocytochemical staining for obtaining better special resolution with light microscopy image processing. Despite these problems, we were unable to detect any significant qualitative differences for the following wound markers: (1) Collagen Type 3, (2) Hematotoxylin and Eosin, and (3) Macrophage Factor 13. All protein markers were isolated from rat sources and antibodies prepared and tested for cross reactivity with other molecules at the University of Wisconsin Hybridoma Facility. However, rat skin from the non lesioned site 'normal' showed interesting biochemical results. Skin was prepared for the following measurements: (1) DNA content, (2) Collagen content by hydroxyproline, and (3) uronic acid content and estimation of ground substance. The results indicated there was a non-significant increase (10%) in the DNA concentration of skin from flight animals. However, the data expressed as a ratio DNA/Collagen estimates the cell or nuclear density that supports a given quantity of collagen showed a dramatic increase in the flight group (33%). This means flight conditions may have slowed down collagen secretion and/or increased cell proliferation in adult rat skin. Further biochemical tests are being done to determine the crosslinking of elastin which will enhance the insight to assessing changes in skin turnover.

  16. Experiment K-7-29: Connective Tissue Studies. Part 1; Rat Skin, Normal and Repair

    Science.gov (United States)

    Vailas, A. C.; Grindeland, R.; Ashman, R.; Choy, V.; Durnova, G.; Graf, B.; Griffith, P.; Kaplansky, A. S.; Kolis, S.; Martinez, D.; hide

    1994-01-01

    The skin repair studies started to be problematic for the following reasons: (1) It was very difficult to locate the wound and many lesions were not of the same dimensions. A considerable amount of time was devoted to the identification of the wound using polarized light. We understand that this experiment was added on to the overall project. Marking of the wound site and standard dimensions should be recommended for the next flight experiment. (2) The tissue was frozen, therefore thawing and fixation caused problems with some of the immunocytochemical staining for obtaining better special resolution with light microscopy image processing. Despite these problems, we were unable to detect any significant qualitative differences for the following wound markers: (1) Collagen Type 3, (2) Hematotoxylin and Eosin, and (3) Macrophage Factor 13. All protein markers were isolated from rat sources and antibodies prepared and tested for cross reactivity with other molecules at the University of Wisconsin Hybridoma Facility. However, rat skin from the non lesioned site 'normal' showed interesting biochemical results. Skin was prepared for the following measurements: (1) DNA content, (2) Collagen content by hydroxyproline, and (3) uronic acid content and estimation of ground substance. The results indicated there was a non-significant increase (10%) in the DNA concentration of skin from flight animals. However, the data expressed as a ratio DNA/Collagen estimates the cell or nuclear density that supports a given quantity of collagen showed a dramatic increase in the flight group (33%). This means flight conditions may have slowed down collagen secretion and/or increased cell proliferation in adult rat skin. Further biochemical tests are being done to determine the crosslinking of elastin which will enhance the insight to assessing changes in skin turnover.

  17. Diffusion of responsibility attenuates altruistic punishment: A functional magnetic resonance imaging effective connectivity study.

    Science.gov (United States)

    Feng, Chunliang; Deshpande, Gopikrishna; Liu, Chao; Gu, Ruolei; Luo, Yue-Jia; Krueger, Frank

    2016-02-01

    Humans altruistically punish violators of social norms to enforce cooperation and pro-social behaviors. However, such altruistic behaviors diminish when others are present, due to a diffusion of responsibility. We investigated the neural signatures underlying the modulations of diffusion of responsibility on altruistic punishment, conjoining a third-party punishment task with event-related functional magnetic resonance imaging and multivariate Granger causality mapping. In our study, participants acted as impartial third-party decision-makers and decided how to punish norm violations under two different social contexts: alone (i.e., full responsibility) or in the presence of putative other third-party decision makers (i.e., diffused responsibility). Our behavioral results demonstrated that the diffusion of responsibility served as a mediator of context-dependent punishment. In the presence of putative others, participants who felt less responsible also punished less severely in response to norm violations. Our neural results revealed that underlying this behavioral effect was a network of interconnected brain regions. For unfair relative to fair splits, the presence of others led to attenuated responses in brain regions implicated in signaling norm violations (e.g., AI) and to increased responses in brain regions implicated in calculating values of norm violations (e.g., vmPFC, precuneus) and mentalizing about others (dmPFC). The dmPFC acted as the driver of the punishment network, modulating target regions, such as AI, vmPFC, and precuneus, to adjust altruistic punishment behavior. Our results uncovered the neural basis of the influence of diffusion of responsibility on altruistic punishment and highlighted the role of the mentalizing network in this important phenomenon. Hum Brain Mapp 37:663-677, 2016. © 2015 Wiley Periodicals, Inc.

  18. Storage of phase-coded patterns via STDP in fully-connected and sparse network: a study of the network capacity

    Directory of Open Access Journals (Sweden)

    Silvia Scarpetta

    2010-08-01

    Full Text Available We study the storage and retrieval of phase-coded patterns as stable dynamical attractors in recurrent neural networks, for both an analog and a integrate-and-fire spiking model. The synaptic strength is determined by a learning rule based on spike-time-dependent plasticity, with an asymmetric time window depending on the relative timing between pre- and post-synaptic activity. We store multiple patterns and study the network capacity. For the analog model, we find that the network capacity scales linearly with the network size, and that both capacity and the oscillation frequency of the retrieval state depend on the asymmetry of the learning time window. In addition to fully-connected networks, we study sparse networks, where each neuron is connected only to a small number $zll N$ of other neurons. Connections can be short range, between neighboring neurons placed on a regular lattice, or long range, between randomly chosen pairs of neurons. We find that a small fraction of long range connections is able to amplify the capacity of the network. This imply that a small-world-network topology is optimal, as a compromise between the cost of long range connections and the capacity increase. Also in the spiking integrate and fire model the crucial result of storing and retrieval of multiple phase-coded patterns is observed. The capacity of the fully-connected spiking network is investigated, together with the relation between oscillation frequency of retrieval state and window asymmetry.

  19. Spatial heterogeneity of the relation between resting-state connectivity and blood flow: an important consideration for pharmacological studies

    NARCIS (Netherlands)

    Khalili-Mahani, N.; Osch, M.J.; Rooij, M.D.; Beckmann, C.F.; Buchem, van M.A.; Dahan, A.; Gerven, van J.M.; Robouts, S.A.

    2014-01-01

    Resting state fMRI (RSfMRI) and arterial spin labeling (ASL) provide the field of pharmacological Neuroimaging tool for investigating states of brain activity in terms of functional connectivity or cerebral blood flow (CBF). Functional connectivity reflects the degree of synchrony or correlation of

  20. City/Sea Searching for a New Connection. Regeneration Proposal for Naples Waterfront Like an Harbourscape: Comparing Three Case Studies

    Directory of Open Access Journals (Sweden)

    Michelangelo Russo

    2014-05-01

    Full Text Available The port is a strategic area of transition, where it is possible to perceive the territory-landscape and the urban front. However it lost its urban character, gradually becoming an high specialized independent machines, a sectorial infrastructure divided from the city: this phenomenon has created increasingly socio-economical marginalization.  Within a double view, lengthwise and transverse, we can describe the port as a space closed to the city and as an unfathomable barrier for the transverse flows that previously connected the waterfront to the city. The paper examines the case study of Naples, where the port expansion continues to grow without any integration with other parts of the city, distorting its “urban area” role, establishing its independence and making urban system compatibility conditions even weaker. The functional and physical division increases the perception of the port as a barrier rather than a filter. Turning the sense of these conditions aims at rethinking waterfront as a public space, a place where integration and specialization spaces become new open and accessible spatial devices. In some contemporary European and American cities (Aalborg, Oslo and Toronto we could see the port as multifunctional system, an interdisciplinary project that creates urban spaces integrated to the city and that allows the coexistence of different uses. The project of a new public space between the sea and the hinterland could involve all these conflicting functions creating, with different strategies, a potential multifunctional landscape. In Naples as well, where the waterfront is still waiting to be re-connected with the story of the city itself.

  1. Missed connections: A case study of the social networks of physics doctoral students in a single department

    Science.gov (United States)

    Knaub, Alexis Victoria

    Gender disparity is an issue among the many science, technology, engineering, and mathematics (STEM) fields. Although many previous studies examine gender issues in STEM as an aggregate discipline, there are unique issues to each of the fields that are considered STEM fields. Some fields, such as physics, have fewer women graduating with degrees than other fields. This suggests that women's experiences vary by STEM field. The majority of previous research also examines gender and other disparities at either the nationwide or individual level. This project entailed social network analysis through survey and interview data to examine a single physics department's doctoral students in order to provide a comprehensive look at student social experiences. In addition to examining gender, other demographic variables were studied to see if the results are truly associated with gender; these variables include race/ethnicity, year in program, student type, relationship status, research type, undergraduate institute, and subfield. Data were examined to determine if there are relationships to social connections and outcome variables such as persistence in completing the degree and the time to degree. Data collected on faculty were used to rank faculty members; data such as h-indices and number of students graduate over the past 5 years were collected. Fifty-five (55) of 110 possible participants completed the survey; forty-three are male, and twelve are female. Twenty-eight of the fifty-five survey participants were interview; twenty-three are male, and five are female. Findings for peer networks include that peer networks are established during the first year and do not change drastically as one progresses in the program. Geographic location within the campus affects socializing with peers. Connections to fellow students are not necessarily reciprocated; the maximum percentage of reciprocated connections is 60%. The number of connections one has varies by network purpose

  2. Altered topological properties of functional network connectivity in schizophrenia during resting state: a small-world brain network study.

    Science.gov (United States)

    Yu, Qingbao; Sui, Jing; Rachakonda, Srinivas; He, Hao; Gruner, William; Pearlson, Godfrey; Kiehl, Kent A; Calhoun, Vince D

    2011-01-01

    Aberrant topological properties of small-world human brain networks in patients with schizophrenia (SZ) have been documented in previous neuroimaging studies. Aberrant functional network connectivity (FNC, temporal relationships among independent component time courses) has also been found in SZ by a previous resting state functional magnetic resonance imaging (fMRI) study. However, no study has yet determined if topological properties of FNC are also altered in SZ. In this study, small-world network metrics of FNC during the resting state were examined in both healthy controls (HCs) and SZ subjects. FMRI data were obtained from 19 HCs and 19 SZ. Brain images were decomposed into independent components (ICs) by group independent component analysis (ICA). FNC maps were constructed via a partial correlation analysis of ICA time courses. A set of undirected graphs were built by thresholding the FNC maps and the small-world network metrics of these maps were evaluated. Our results demonstrated significantly altered topological properties of FNC in SZ relative to controls. In addition, topological measures of many ICs involving frontal, parietal, occipital and cerebellar areas were altered in SZ relative to controls. Specifically, topological measures of whole network and specific components in SZ were correlated with scores on the negative symptom scale of the Positive and Negative Symptom Scale (PANSS). These findings suggest that aberrant architecture of small-world brain topology in SZ consists of ICA temporally coherent brain networks.

  3. Functional connectivity of motor cortical network in patients with brachial plexus avulsion injury after contralateral cervical nerve transfer: a resting-state fMRI study

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Aihong; Cheng, Xiaoguang; Liang, Wei; Bai, Rongjie [The 4th Medical College of Peking University, Department of Radiology, Beijing Jishuitan Hospital, Xicheng Qu, Beijing (China); Wang, Shufeng; Xue, Yunhao; Li, Wenjun [The 4th Medical College of Peking University, Department of Hand Surgery, Beijing Jishuitan Hospital, Beijing (China)

    2017-03-15

    The purpose of this study is to assess the functional connectivity of the motor cortical network in patients with brachial plexus avulsion injury (BPAI) after contralateral C7 nerve transfer, using resting-state functional magnetic resonance imaging (RS-fMRI). Twelve patients with total brachial plexus root avulsion underwent RS-fMRI after contralateral C7 nerve transfer. Seventeen healthy volunteers were also included in this fMRI study as controls. The hand motor seed regions were defined as region of interests in the bilateral hemispheres. The seed-based functional connectivity was calculated in all the subjects. Differences in functional connectivity of the motor cortical network between patients and healthy controls were compared. The inter-hemispheric functional connectivity of the M1 areas was increased in patients with BPAI compared with the controls. The inter-hemispheric functional connectivity between the supplementary motor areas was reduced bilaterally. The resting-state inter-hemispheric functional connectivity of the bilateral M1 areas is altered in patients after contralateral C7 nerve transfer, suggesting a functional reorganization of cerebral cortex. (orig.)

  4. A feasibility study of stationary and dual-axis tracking grid-connected photovoltaic systems in the Upper Midwest

    Science.gov (United States)

    Warren, Ryan Duwain

    Three primary objectives were defined for this work. The first objective was to determine, assess, and compare the performance, heat transfer characteristics, economics, and feasibility of real-world stationary and dual-axis tracking grid-connected photovoltaic (PV) systems in the Upper Midwest. This objective was achieved by installing two grid-connected PV systems with different mounting schemes in central Iowa, implementing extensive data acquisition systems, monitoring operation of the PV systems for one full year, and performing detailed experimental performance and economic studies. The two PV systems that were installed, monitored, and analyzed included a 4.59 kWp roof-mounted stationary system oriented for maximum annual energy production, and a 1.02 kWp pole-mounted actively controlled dual-axis tracking system. The second objective was to demonstrate the actual use and performance of real-world stationary and dual-axis tracking grid-connected PV systems used for building energy generation applications. This objective was achieved by offering the installed PV systems to the public for demonstration purposes and through the development of three computer-based tools: a software interface that has the ability to display real-time and historical performance and meteorological data of both systems side-by-side, a software interface that shows real-time and historical video and photographs of each system, and a calculator that can predict performance and economics of stationary and dual-axis tracking grid-connected PV systems at various locations in the United States. The final objective was to disseminate this work to social, professional, scientific, and academic communities in a way that is applicable, objective, accurate, accessible, and comprehensible. This final objective will be addressed by publishing the results of this work and making the computer-based tools available on a public website (www.energy.iastate.edu/Renewable/solar). Detailed experimental

  5. UNESCO Thematic Initiative ``Astronomy and World Heritage'': studies and research on technological heritage connected with space exploration

    Science.gov (United States)

    Sidorenko, Anna

    The Convention concerning the protection of the World Cultural and Natural Heritage (1972) provides a unique opportunity to preserve exceptional properties world-wide and to raise awareness about the Outstanding Universal Value of these properties. The mission of UNESCO regarding World Heritage consists of assisting the States Parties to this Convention to safeguard properties inscribed on the World Heritage List, to support activities led by States Parties in the preservation of World Heritage, and to encourage international cooperation in heritage conservation. Considering that sites related to science and technology are among the most under-represented on the World Heritage List and recognizing the absence of an integrated thematic approach for such sites, the World Heritage Committee launched the Thematic Initiative “Astronomy and World Heritage”. Developed in close collaboration between the UNESCO World Heritage Centre, the International Astronomical Union (IAU) and the International Council on Monuments and Sites (ICOMOS), and implemented by the National Focal Points world-wide, the Thematic Initiative on Astronomy and World Heritage aims to establish a link between Science and Culture towards the recognition of scientific values of sites linked to astronomy. It provides an opportunity not only to identify the properties but also to keep their memory alive and preserve them from progressive deterioration. The implementation of this initiative has revealed numerous issues that need to be addressed, and in particular in the domain of technological heritage connected with space exploration. For this reason, the World Heritage Committee during its 36th session (Saint Petersburg, 2012) encouraged cooperation between the UNESCO World Heritage Centre, specialized agencies and relevant interdisciplinary scientific initiatives towards the elaboration of a Global Thematic Study on Heritage of Science and Technology, including studies and research on technological

  6. Changes of Brain Connectivity in the Primary Motor Cortex After Subcortical Stroke: A Multimodal Magnetic Resonance Imaging Study.

    Science.gov (United States)

    Li, Yongxin; Wang, Defeng; Zhang, Heye; Wang, Ya; Wu, Ping; Zhang, Hongwu; Yang, Yang; Huang, Wenhua

    2016-02-01

    The authors investigated the changes in connectivity networks of the bilateral primary motor cortex (M1) of subcortical stroke patients using a multimodal neuroimaging approach with antiplatelet therapy. Nineteen patients were scanned at 2 time points: before and 1 month after the treatment. The authors assessed the resting-state functional connectivity (FC) and probabilistic fiber tracking of left and right M1 of every patient, and then compared these results to the 15 healthy controls. The authors also evaluated the correlations between the neuroimaging results and clinical scores.Compared with the controls, the patients showed a significant decrease of FC in the contralateral motor cortex before treatment, and the disrupted FC was restored after treatment. The fiber tracking results in the controls indicated that the body of the corpus callosum should be the main pathway connecting the M1 and contralateral hemispheres. All patients exhibited reduced probability of structural connectivity within this pathway before treatment and which was restored after treatment. Significant correlations were also found in these patients between the connectivity results and clinical scores, which might imply that the connectivity of M1 can be used to evaluate the motor skills in stroke patients.These findings can help elucidate the neural mechanisms responsible for the brain connectivity recovery after stroke.

  7. Reciprocal connections between CART-immunoreactive, hypothalamic paraventricular neurons and serotonergic dorsal raphe cells in the rat: Light microscopic study.

    Science.gov (United States)

    Lee, Ji S; Lee, Hyun S

    2014-04-29

    Based on the overlapping physiological roles of cocaine- and amphetamine-regulated transcript (CART) peptides and serotonin, the present study examined the anatomical connection between the hypothalamic paraventricular nucleus (PVN) and the dorsal raphe (DR). The first series of experiments were performed to investigate descending projections from the CART-immunoreactive (CART-ir) PVN to serotonergic DR cells. CART-ir varicosities made contact with serotonergic DR neurons. An anterograde tracing study revealed that varicosities originating from the PVN formed close appositions to serotonergic neuronal profiles along the entire rostro-caudal extent of the DR. A retrograde study demonstrated that CART neurons projecting to the DR were mainly localized in the caudal parvicellular PVN, comprising approximately 3.0%±0.4% (n=8) of total CART cells. A second series of experiments was performed to investigate ascending projections from the DR to CART-ir PVN cells. Serotonin transporter-ir boutons made contact with CART-ir PVN neurons. Anterograde tracing revealed that varicosities originating from the DR formed close appositions to CART-ir PVN cells. Retrograde examination demonstrated that serotonergic neurons projecting to the parvicellular PVN were located along the entire rostro-caudal extent of the DR. The present observation provided an anatomical basis for accumulating evidence in the literature that suggests a functional interaction between the CART and serotonin systems during the regulation of energy balance, emotional behavior, and arousal.

  8. Impaired prefrontal-amygdala effective connectivity is responsible for the dysfunction of emotion process in major depressive disorder: a dynamic causal modeling study on MEG.

    Science.gov (United States)

    Lu, Qing; Li, Haoran; Luo, Guoping; Wang, Yi; Tang, Hao; Han, Li; Yao, Zhijian

    2012-08-15

    Depression is proved to be associated with the dysfunction of prefrontal-limbic neural circuit, especially during emotion processing procedure. Related explorations have been undertaken from the aspects of abnormal activation and functional connectivity. However, the mechanism of the dysfunction of coordinated interactions remains unknown and is still a matter of debate. The present study gave direct evidence of this issue from the aspect of effective connectivity via dynamic causal modeling (DCM). 20 major depressive disorder (MDD) patients and 20 healthy controls were recruited to attend facial emotional stimulus during MEG recording. Bayesian model selection (BMS) was applied to choose the best model. Results under the optimal model showed that top-down endogenous effective connectivity from the dorsolateral prefrontal cortex (DLPFC) to the amygdala was greatly impaired in patients relative to health controls; while bottom-up endogenous effective connectivity from the amygdala to the anterior cingulate cortex (ACC) as well as modulatory effective connectivity from ACC to DLPFC was significantly increased. We inferred the incapable DLPFC failed to exert influence on amygdala, and finally lead to enhanced amygdala-ACC and ACC-DLPFC bottom-up effects. Such impaired prefrontal-amygdala connectivity was supposed to be responsible for the dysfunction in MDD when dealing with emotional stimuli.

  9. A Pilot Study Examining Physical and Social Warmth: Higher (Non-Febrile) Oral Temperature Is Associated with Greater Feelings of Social Connection.

    Science.gov (United States)

    Inagaki, Tristen K; Irwin, Michael R; Moieni, Mona; Jevtic, Ivana; Eisenberger, Naomi I

    2016-01-01

    An emerging literature suggests that experiences of physical warmth contribute to social warmth-the experience of feeling connected to others. Thus, thermoregulatory systems, which help maintain our relatively warm internal body temperatures, may also support feelings of social connection. However, the association between internal body temperature and feelings of connection has not been examined. Furthermore, the origins of the link between physical and social warmth, via learning during early experiences with a caregiver or via innate, co-evolved mechanisms, remain unclear. The current study examined the relationship between oral temperature and feelings of social connection as well as whether early caregiver experiences moderated this relationship. Extending the existing literature, higher oral temperature readings were associated with greater feelings of social connection. Moreover, early caregiver experiences did not moderate this association, suggesting that the physical-social warmth overlap may not be altered by early social experience. Results provide additional support for the link between experiences of physical warmth and social warmth and add to existing theories that highlight social connection as a basic need on its own.

  10. A Pilot Study Examining Physical and Social Warmth: Higher (Non-Febrile Oral Temperature Is Associated with Greater Feelings of Social Connection.

    Directory of Open Access Journals (Sweden)

    Tristen K Inagaki

    Full Text Available An emerging literature suggests that experiences of physical warmth contribute to social warmth-the experience of feeling connected to others. Thus, thermoregulatory systems, which help maintain our relatively warm internal body temperatures, may also support feelings of social connection. However, the association between internal body temperature and feelings of connection has not been examined. Furthermore, the origins of the link between physical and social warmth, via learning during early experiences with a caregiver or via innate, co-evolved mechanisms, remain unclear. The current study examined the relationship between oral temperature and feelings of social connection as well as whether early caregiver experiences moderated this relationship. Extending the existing literature, higher oral temperature readings were associated with greater feelings of social connection. Moreover, early caregiver experiences did not moderate this association, suggesting that the physical-social warmth overlap may not be altered by early social experience. Results provide additional support for the link between experiences of physical warmth and social warmth and add to existing theories that highlight social connection as a basic need on its own.

  11. A Pilot Study Examining Physical and Social Warmth: Higher (Non-Febrile) Oral Temperature Is Associated with Greater Feelings of Social Connection

    Science.gov (United States)

    Inagaki, Tristen K.; Irwin, Michael R.; Moieni, Mona; Jevtic, Ivana; Eisenberger, Naomi I.

    2016-01-01

    An emerging literature suggests that experiences of physical warmth contribute to social warmth—the experience of feeling connected to others. Thus, thermoregulatory systems, which help maintain our relatively warm internal body temperatures, may also support feelings of social connection. However, the association between internal body temperature and feelings of connection has not been examined. Furthermore, the origins of the link between physical and social warmth, via learning during early experiences with a caregiver or via innate, co-evolved mechanisms, remain unclear. The current study examined the relationship between oral temperature and feelings of social connection as well as whether early caregiver experiences moderated this relationship. Extending the existing literature, higher oral temperature readings were associated with greater feelings of social connection. Moreover, early caregiver experiences did not moderate this association, suggesting that the physical-social warmth overlap may not be altered by early social experience. Results provide additional support for the link between experiences of physical warmth and social warmth and add to existing theories that highlight social connection as a basic need on its own. PMID:27257914

  12. Solar Cycle Variation and Multipoint Studies of ICME Properties

    Science.gov (United States)

    Russell, C. T.

    2005-01-01

    The goal of the Living With a Star program is to understand the Sun-Earth connection sufficiently well that we can solve problems critical to life and society. This can most effectively be done in the short term using observations from our past and on-going programs. Not only can this approach solve some of the pressing issues but also it can provide ideas for the deployment of future spacecraft in the LWS program. The proposed effort uses data from NEAR, SOHO, Wind, ACE and Pioneer Venus in quadrature, multipoint, and solar cycle studies to study the interplanetary coronal mass ejection and its role in the magnetic flux cycle of the Sun. ICMEs are most important to the LWS objectives because the solar wind conditions associated with these structures are the most geoeffective of any solar wind phenomena. Their ability to produce strong geomagnetic disturbances arises first because of their high speed. This high speed overtakes the ambient solar wind producing a bow shock wave similar to the terrestrial bow shock. In the new techniques we develop as part of this effort we exploit this feature of ICMEs. This shocked plasma has a greater velocity, higher density and stronger magnetic field than the ambient solar wind, conditions that can enhance geomagnetic activity. The driving ICME is a large magnetic structure expanding outward in the solar wind [Gosling, 19961. The ICMEs magnetic field is generally much higher than that in the ambient solar wind and the velocity is high. The twisted nature of the magnetic field in an ICME almost ensures that sometime during the ICME conditions favorable for geomagnetic storm initiation will occur.

  13. In vitro study on the disinfectability of two split-septum needle-free connection devices using different disinfection procedures

    Science.gov (United States)

    Engelhart, Steffen; Exner, Martin; Simon, Arne

    2015-01-01

    This in vitro study investigated the external disinfection of two needle-free connection devices (NFC) using Octeniderm® (spraying and wiping technique) vs. Descoderm® pads (wiping technique). The split-septum membrane of the NFC was contaminated with >105 CFU K. pneumoniae or S. epidermidis. The efficacy of the disinfection at 30 sec. exposure time was controlled by taking a swab sample and by flushing the NFC with sterile 0.9% sodium chloride solution. Disinfection with octenidine dihydrochloride 0.1 g, 1-Propanol 30.0 g, and 2-Propanol 45.0 g in 100 g solution was highly effective (CFU reduction ≥4 log) against both microorganisms, whereas the use of 63.1 g 2-Propanol in 100 ml solution led to residual contamination with S. epidermidis. Our investigation underlines that (i) in clinical practice disinfection of NFCs before use is mandatory, and that (ii) details of disinfection technique are of utmost importance regarding their efficacy. Our investigation revealed no significant differences between both split-septum NFC types. Clinical studies are needed to confirm a possible superiority of disinfectants with long-lasting residual antimicrobial activity. PMID:26693394

  14. In vitro study on the disinfectability of two split-septum needle-free connection devices using different disinfection procedures

    Directory of Open Access Journals (Sweden)

    Engelhart, Steffen

    2015-12-01

    Full Text Available This in vitro study investigated the external disinfection of two needle-free connection devices (NFC using Octeniderm (spraying and wiping technique vs. Descoderm pads (wiping technique. The split-septum membrane of the NFC was contaminated with >10 CFU . The efficacy of the disinfection at 30 sec. exposure time was controlled by taking a swab sample and by flushing the NFC with sterile 0.9% sodium chloride solution. Disinfection with octenidine dihydrochloride 0.1 g, 1-Propanol 30.0 g, and 2-Propanol 45.0 g in solution was highly effective (CFU reduction ≥4 log against both microorganisms, whereas the use of 63.1 g 2-Propanol in 100 ml solution led to residual contamination with . Our investigation underlines that (i in clinical practice disinfection of NFCs before use is mandatory, and that (ii details of disinfection technique are of utmost importance regarding their efficacy. Our investigation revealed no significant differences between both split-septum NFC types. Clinical studies are needed to confirm a possible superiority of disinfectants with long-lasting residual antimicrobial activity.

  15. Impairments in Brain Perfusion, Metabolites, Functional Connectivity, and Cognition in Severe Asymptomatic Carotid Stenosis Patients: An Integrated MRI Study

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2017-01-01

    Full Text Available Carotid artery stenosis without transient ischemic attack (TIA or stroke is considered as “asymptomatic.” However, recent studies have demonstrated that these asymptomatic carotid artery stenosis (aCAS patients had cognitive impairment in tests of executive function, psychomotor speed, and memory, indicating that “asymptomatic” carotid stenosis may not be truly asymptomatic. In this study, when 19 aCAS patients compared with 24 healthy controls, aCAS patients showed significantly poorer performance on global cognition, memory, and executive function. By utilizing an integrated MRI including pulsed arterial spin labeling (pASL MRI, Proton MR Spectroscopy (MRS, and resting-state functional MRI (R-fMRI, we also found that aCAS patients suffered decreased cerebral blood flow (CBF mainly in the Left Frontal Gyrus and had decreased NAA/Cr ratio in the left hippocampus and decreased connectivity to the posterior cingulate cortex (PCC in the anterior part of default mode network (DMN.

  16. A multicenter study of the early detection of synaptic dysfunction in Mild Cognitive Impairment using Magnetoencephalography-derived functional connectivity

    Directory of Open Access Journals (Sweden)

    Fernando Maestú, PhD

    2015-01-01

    Full Text Available Synaptic disruption is an early pathological sign of the neurodegeneration of Dementia of the Alzheimer's type (DAT. The changes in network synchronization are evident in patients with Mild Cognitive Impairment (MCI at the group level, but there are very few Magnetoencephalography (MEG studies regarding discrimination at the individual level. In an international multicenter study, we used MEG and functional connectivity metrics to discriminate MCI from normal aging at the individual person level. A labeled sample of features (links that distinguished MCI patients from controls in a training dataset was used to classify MCI subjects in two testing datasets from four other MEG centers. We identified a pattern of neuronal hypersynchronization in MCI, in which the features that best discriminated MCI were fronto-parietal and interhemispheric links. The hypersynchronization pattern found in the MCI patients was stable across the five different centers, and may be considered an early sign of synaptic disruption and a possible preclinical biomarker for MCI/DAT.

  17. External thoracic duct-venous shunt in conscious pigs for long term studies of connective tissue metabolites in lymph

    DEFF Research Database (Denmark)

    Jensen, L T; Olesen, H P; Risteli, J;

    1990-01-01

    An experimental animal model for lymph studies is described. Thoracic duct-venous shunt was established in 12 pigs. Shunt patency averaged 5.5 days. The composition of connective tissue metabolites in lymph and serum were investigated during a standardized surgical operation (thoracotomy) under g...... instead of dogs and sheep in studies on lymph. The effect of surgery/anesthesia must be taken into consideration....... general anesthesia. We measured the carboxyterminal propeptide of type I procollagen (PICP), the aminoterminal propeptide of type III procollagen (PIIINP) hyaluronan (HA) and total protein. During surgery/anesthesia lymph PICP (p less than 0.04), lymph PIIINP (p less than 0.03) and serum PIIINP (p less...... is a major route of tissue clearance for these components. The lymph/serum ratio of PICP was 1.0 in conscious pigs, indicating a direct release into the circulation. Total protein in lymph decreased (p less than 0.04) during surgery/anesthesia, whereas no changes were observed in serum. Pigs can be used...

  18. The role of water and sediment connectivity in integrated flood management: a case study on the island of Saint Lucia

    Science.gov (United States)

    Jetten, Victor; van Westen, Cees; Ettema, Janneke; van den Bout, Bastian

    2016-04-01

    Disaster Risk Management combines the effects of natural hazards in time and space, with elements at risk, such as ourselves, infrastructure or other elements that have a value in our society. The risk in this case is defined as the sum of potential consequences of one or more hazards and can be expressed as potential damages. Generally, we attempt to reduce risk by better risk management, such as increase of resilience, protection and spatial planning. Caribbean islands are hit by hurricanes and tropical storms with a frequency of 1 to 2 every 10 years, with devastating consequences in terms of flash floods and landslides. The islands basically consist of a central (volcanic) mountain range, with medium and small sized catchments radiating outward towards the ocean. The coastal zone is inhabited, while the ring road network is essential for functioning of the island. An example of a case study is given for the island of Saint Lucia. Recorded rainfall intensities during tropical storms of 12 rainfall stations surpass 200 mm/h, causing immediate flash floods. Very often however, sediment is a forgotten variable in flash flood management: protection and mitigation measures as well as spatial planning all focus on the hydrology, the extent and depth of flood water, and sometimes of flood velocities. With recent developments, the opensource model LISEM includes hydrology and runoff, flooding, and erosion, transport and deposition both in runoff, channel flow and flood waters. We will discuss the practical solutions we implemented in connecting slopes, river channels and floodplains in terms of water and sediment, and the strength and weaknesses we have encountered so far. Catchment analysis shows two main effects: on the one hand in almost all cases upstream flooding serves as a temporary water storage that prevents further damage downstream, while on the other hand, erosion upstream often blocks bridges and decreases channel storage downstream, which increases the

  19. Anterior cingulate cortex-related connectivity in first-episode schizophrenia: a spectral dynamic causal modeling study with functional magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Long-Biao eCui

    2015-11-01

    Full Text Available Understanding the neural basis of schizophrenia (SZ is important for shedding light on the neurobiological mechanisms underlying this mental disorder. Structural and functional alterations in the anterior cingulate cortex (ACC, dorsolateral prefrontal cortex (DLPFC, hippocampus, and medial prefrontal cortex (MPFC have been implicated in the neurobiology of SZ. However, the effective connectivity among them in SZ remains unclear. The current study investigated how neuronal pathways involving these regions were affected in first-episode SZ using functional magnetic resonance imaging (fMRI. Forty-nine patients with a first-episode of psychosis and diagnosis of SZ—according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision—were studied. Fifty healthy controls (HCs were included for comparison. All subjects underwent resting state fMRI. We used spectral dynamic causal modeling (DCM to estimate directed connections among the bilateral ACC, DLPFC, hippocampus, and MPFC. We characterized the differences using Bayesian parameter averaging (BPA in addition to classical inference (t-test. In addition to common effective connectivity in these two groups, HCs displayed widespread significant connections predominantly involved in ACC not detected in SZ patients, but SZ showed few connections. Based on BPA results, SZ patients exhibited anterior cingulate cortico-prefrontal-hippocampal hyperconnectivity, as well as ACC-related and hippocampal-dorsolateral prefrontal-medial prefrontal hypoconnectivity. In summary, sDCM revealed the pattern of effective connectivity involving ACC in patients with first-episode SZ. This study provides a potential link between SZ and dysfunction of ACC, creating an ideal situation to associate mechanisms behind SZ with aberrant connectivity among these cognition and emotion-related regions.

  20. Relationship between functional connectivity and motor function assessment in stroke patients with hemiplegia: a resting-state functional MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ye; Wang, Li; Zhang, Jingna; Sang, Linqiong; Li, Pengyue; Qiu, Mingguo [Third Military Medical University, Department of Medical Imaging, College of Biomedical Engineering, Chongqing (China); Liu, Hongliang; Yan, Rubing [Third Military Medical University, Department of Rehabilitation, Southwest Hospital, Chongqing (China); Yang, Jun; Wang, Jian [Third Military Medical University, Department of Radiology, Southwest Hospital, Chongqing (China)

    2016-05-15

    Resting-state functional magnetic resonance imaging (fMRI) has been used to examine the brain mechanisms of stroke patients with hemiplegia, but the relationship between functional connectivity (FC) and treatment-induced motor function recovery has not yet been fully investigated. This study aimed to identify the brain FC changes in stroke patients and study the relationship between FC and motor function assessment using the resting-state fMRI. Seventeen stroke patients with hemiplegia and fifteen healthy control subjects (HCSs) were recruited in this study. We compared the FC between the ipsilesional primary motor cortex (M1) and the whole brain of the patients with the FC of the HCSs and studied the FC changes in the patients before and after conventional rehabilitation and motor imagery therapy. Additionally, correlations between the FC change and motor function of the patients were studied. Compared to the HCSs, the FC in the patient group was significantly increased between the ipsilesional M1 and the ipsilesional inferior parietal cortex, frontal gyrus, supplementary motor area (SMA), and contralesional angular and decreased between the ipsilesional M1 and bilateral M1. After the treatment, the FC between the ipsilesional M1 and contralesional M1 increased while the FC between the ipsilesional M1 and ipsilesional SMA and paracentral lobule decreased. A statistically significant correlation was found between the FC change in the bilateral M1 and the Fugl-Meyer assessment (FMA) score change. Our results revealed an abnormal motor network after stroke and suggested that the FC could serve as a biomarker of motor function recovery in stroke patients with hemiplegia. (orig.)

  1. Decreased Functional Connectivity of Homotopic Brain Regions in Chronic Stroke Patients: A Resting State fMRI Study

    Science.gov (United States)

    Chen, Chuang; Zheng, Xiaohui; Sun, Fenfen; Zhang, Xiaoli; Tian, Jing; Fan, Mingxia; Wu, Yi; Jia, Jie

    2016-01-01

    The recovery of motor functions is accompanied by brain reorganization, and identifying the inter-hemispheric interaction post stroke will conduce to more targeted treatments. However, the alterations of bi-hemispheric coordination pattern between homologous areas in the whole brain for chronic stroke patients were still unclear. The present study focuses on the functional connectivity (FC) of mirror regions of the whole brain to investigate the inter-hemispheric interaction using a new fMRI method named voxel-mirrored homotopic connectivity (VMHC). Thirty left subcortical chronic stroke patients with pure motor deficits and 37 well-matched healthy controls (HCs) underwent resting-state fMRI scans. We employed a VMHC analysis to determine the brain areas showed significant differences between groups in FC between homologous regions, and we explored the relationships between the mean VMHC of each survived area and clinical tests within patient group using Pearson correlation. In addition, the brain areas showed significant correlations between the mean VMHC and clinical tests were defined as the seed regions for whole brain FC analysis. Relative to HCs, patients group displayed lower VMHC in the precentral gyrus, postcentral gyrus, inferior frontal gyrus, middle temporal gyrus, calcarine gyrus, thalamus, cerebellum anterior lobe, and cerebellum posterior lobe (CPL). Moreover, the VMHC of CPL was positively correlated with the Fugl–Meyer Score of hand (FMA-H), while a negative correlation between illness duration and the VMHC of this region was also detected. Furthermore, we found that when compared with HCs, the right CPL exhibited reduced FC with the left precentral gyrus, inferior frontal gyrus, inferior parietal lobule, middle temporal gyrus, thalamus and hippocampus. Our results suggest that the functional coordination across hemispheres is impaired in chronic stroke patients, and increased VMHC of the CPL is significantly associated with higher FMA-H scores

  2. Post-traumatic stress influences local and remote functional connectivity: a resting-state functional magnetic resonance imaging study.

    Science.gov (United States)

    Ke, Jun; Chen, Feng; Qi, Rongfeng; Xu, Qiang; Zhong, Yuan; Chen, Lida; Li, Jianjun; Zhang, Li; Lu, Guangming

    2016-10-08

    Post-traumatic stress disorder (PTSD) is associated with alterations in regional brain activation and remote functional connectivity (FC) in limbic and prefrontal cortex. However, little is known about local FC changes following a traumatic event. Resting-state functional magnetic resonance images were collected for typhoon survivors with (n = 27) and without PTSD (n = 33), and healthy controls (n = 30). Local FC was examined by calculating regional homogeneity (ReHo), and remote FC was investigated between regions showing significant ReHo group differences. The PTSD group showed ReHo changes in multiple regions, including the amygdala, parahippocampal gyrus, and prefrontal cortex relative to both control groups. Compared with healthy controls, typhoon survivors had increased ReHo in the insula/inferior frontal gyrus, middle and dorsal anterior cingulate cortex (MCC/dACC), as well as enhanced negative FC between the MCC/dACC and posterior cingulate cortex (PCC)/precuneus. The typhoon-exposed control group exhibited higher ReHo in the PCC/precuneus than the PTSD and healthy control groups. Furthermore, positive correlations were found between PTSD symptom severity and ReHo in several regions. Post-traumatic stress can influence local and remote FC, irrespective of PTSD diagnosis. Future studies are needed to validate the findings and to determine whether the alterations represent pre-existing or acquired deficits.

  3. Modafinil alters intrinsic functional connectivity of the right posterior insula: a pharmacological resting state fMRI study.

    Directory of Open Access Journals (Sweden)

    Nicoletta Cera

    Full Text Available BACKGROUND: Modafinil is employed for the treatment of narcolepsy and has also been, off-label, used to treat cognitive dysfunction in neuropsychiatric disorders. In a previous study, we have reported that single dose administration of modafinil in healthy young subjects enhances fluid reasoning and affects resting state activity in the Fronto Parietal Control (FPC and Dorsal Attention (DAN networks. No changes were found in the Salience Network (SN, a surprising result as the network is involved in the modulation of emotional and fluid reasoning. The insula is crucial hub of the SN and functionally divided in anterior and posterior subregions. METHODOLOGY: Using a seed-based approach, we have now analyzed effects of modafinil on the functional connectivity (FC of insular subregions. PRINCIPAL FINDINGS: Analysis of FC with resting state fMRI (rs-FMRI revealed increased FC between the right posterior insula and the putamen, the superior frontal gyrus and the anterior cingulate cortex in the modafinil-treated group. CONCLUSIONS: Modafinil is considered a putative cognitive enhancer. The rs-fMRI modifications that we have found are consistent with the drug cognitive enhancing properties and indicate subregional targets of action. TRIAL REGISTRATION: ClinicalTrials.gov NCT01684306.

  4. Altered resting-state connectivity in subjects at ultra-high risk for psychosis: an fMRI study

    Directory of Open Access Journals (Sweden)

    Choi Jung-Seok

    2010-10-01

    Full Text Available Abstract Background Individuals at ultra-high risk (UHR for psychosis have self-disturbances and deficits in social cognition and functioning. Midline default network areas, including the medial prefrontal cortex and posterior cingulate cortex, are implicated in self-referential and social cognitive tasks. Thus, the neural substrates within the default mode network (DMN have the potential to mediate self-referential and social cognitive information processing in UHR subjects. Methods This study utilized functional magnetic resonance imaging (fMRI to investigate resting-state DMN and task-related network (TRN functional connectivity in 19 UHR subjects and 20 matched healthy controls. The bilateral posterior cingulate cortex was selected as a seed region, and the intrinsic organization for all subjects was reconstructed on the basis of fMRI time series correlation. Results Default mode areas included the posterior/anterior cingulate cortices, the medial prefrontal cortex, the lateral parietal cortex, and the inferior temporal region. Task-related network areas included the dorsolateral prefrontal cortex, supplementary motor area, the inferior parietal lobule, and middle temporal cortex. Compared to healthy controls, UHR subjects exhibit hyperconnectivity within the default network regions and reduced anti-correlations (or negative correlations nearer to zero between the posterior cingulate cortex and task-related areas. Conclusions These findings suggest that abnormal resting-state network activity may be related with the clinical features of UHR subjects. Neurodevelopmental and anatomical alterations of cortical midline structure might underlie altered intrinsic networks in UHR subjects.

  5. Enamel matrix derivative (emdogain) or subepithelial connective tissue graft for the treatment of adjacent multiple gingival recessions: a pilot study.

    Science.gov (United States)

    Alkan, Eylem Ayhan; Parlar, Ates

    2013-01-01

    One treatment approach for achieving healing by regeneration is the application of enamel matrix derivative (EMD) during periodontal surgery. The aim of this randomized clinical study was to compare the efficacy of EMD with a connective tissue graft (CTG) for the treatment of adjacent Miller Class l and II multiple gingival recessions. Twelve systemically healthy subjects with at least two Miller Class I or II multiple gingival recession defects affecting adjacent teeth on both sides of the mouth were enrolled. The surgical protocol was performed for both groups. The 56 recession defects were evaluated for recession depth (RD), recession width (RW), percentage of root coverage (PRC), height of keratinized tissue (HKT), probing depth (PD), and clinical attachment level (CAL). All measurements were repeated at 6 and 12 months. The mean PRC at the final evaluation was 89% ± 17% for the coronally advanced flap (CAF) + EMD group and 93% ± 17% for the CAF + CTG group. Both treatments resulted in statistically significant decreases in RD and RW and increases in HKT at 6 and 12 months. There was also a significant CAL gain for both groups. PD remained shallow over time. The results demonstrated that both procedures were successful in treating Miller Class I and II multiple gingival recessions; however, the greater results of the CAF + CTG group did not reach a statistically significant level.

  6. The neural processing of second language comprehension modulated by the degree of proficiency: a listening connected speech FMRI study.

    Science.gov (United States)

    Hesling, Isabelle; Dilharreguy, Bixente; Bordessoules, Martine; Allard, Michèle

    2012-01-01

    While the neural network encompassing the processing of the mother tongue (L1) is well defined and has revealed the existence of a bilateral ventral pathway and a left dorsal pathway in which 3 loops have been defined, the question of the processing of a second language (L2) is still a matter of debate. Among variables accounting for the discrepancies in results, the degree of L2 proficiency appears to be one of the main factors. The present study aimed at assessing both pathways in L2, making it possible to determine the degree of mastery of the different speech components (prosody, phonology, semantics and syntax) that are intrinsically embedded within connected speech and that vary according to the degree of proficiency using high degrees of prosodic information. Two groups of high and moderate proficiency in L2 performed an fMRI comprehension task in L1 and L2. The modifications in brain activity observed within the dorsal and the ventral pathways according to L2 proficiency suggest that different processes of L2 are supported by differences in the integrated activity within distributed networks that included the left STSp, the left Spt and the left pars triangularis.

  7. The CONNECT project

    DEFF Research Database (Denmark)

    Assaf, Yaniv; Alexander, Daniel C; Jones, Derek K

    2013-01-01

    diameter and axonal density). This unique insight into both tissue microstructure and connectivity has enormous potential value in understanding the structure and organization of the brain as well as providing unique insights to abnormalities that underpin disease states. The CONNECT (Consortium......In recent years, diffusion MRI has become an extremely important tool for studying the morphology of living brain tissue, as it provides unique insights into both its macrostructure and microstructure. Recent applications of diffusion MRI aimed to characterize the structural connectome using...... tractography to infer connectivity between brain regions. In parallel to the development of tractography, additional diffusion MRI based frameworks (CHARMED, AxCaliber, ActiveAx) were developed enabling the extraction of a multitude of micro-structural parameters (axon diameter distribution, mean axonal...

  8. Sub-epithelial connective tissue graft for root coverage in nonsmokers and smokers: A pilot comparative clinical study

    Directory of Open Access Journals (Sweden)

    Chini Doraswamy Dwarakanath

    2016-01-01

    Full Text Available Background: Gingival recession is a common condition and is more prevalent in smokers. It is widely believed that root coverage procedures in smokers result in less desirable outcome compared to nonsmokers', and there are few controlled studies in literature to support this finding. Therefore, the purpose of this study was to evaluate and compare the outcome of root coverage with sub-epithelial connective tissue graft (SCTG in nonsmokers and smokers. Materials and Methods: A sample of twenty subjects, 10 nonsmokers and 10 smokers were selected each with at least 1 Miller's Class I or II recession on a single rooted tooth. Clinical measurements of probing depth, clinical attachment level (CAL, gingival recession total surface area (GRTSA, depth of recession (RD, width of recession (RW, and width of keratinized tissue were determined at baseline, 3, and 6 months after surgery. Results: The treatment of gingival recession with SCTG and coronally advanced flap showed a decrease in the GRTSA, RD, RW, and an increase in CAL and width of keratinized gingiva in both the groups. However, the intergroup comparison of the clinical parameters showed no statistical significance. About 6 out of 10 nonsmokers (60% and 3 smokers (30% showed complete root coverage. The mean percentage of root coverage of 71.2% in nonsmokers and 38% in smokers was observed. Conclusion: The results of the present study suggest that smoking may negatively influence gingival recession reduction and CAL gain. In addition, smokers may exhibit fewer chances of complete root coverage. Overall, nonsmokers showed better improvements in all the parameters compared to smokers at the end of 6 months.

  9. Connectivity to computers and the Internet among patients with schizophrenia spectrum disorders: a cross-sectional study.

    Science.gov (United States)

    Välimäki, Maritta; Kuosmanen, Lauri; Hätönen, Heli; Koivunen, Marita; Pitkänen, Anneli; Athanasopoulou, Christina; Anttila, Minna

    2017-01-01

    Information and communication technologies have been developed for a variety of health care applications and user groups in the field of health care. This study examined the connectivity to computers and the Internet among patients with schizophrenia spectrum disorders (SSDs). A cross-sectional survey design was used to study 311 adults with SSDs from the inpatient units of two psychiatric hospitals in Finland. The data collection lasted for 20 months and was done through patients' medical records and a self-reported, structured questionnaire. Data analysis included descriptive statistics. In total, 297 patients were included in this study (response rate =96%). More than half of them (n=156; 55%) had a computer and less than half of them (n=127; 44%) had the Internet at home. Of those who generally had access to computers and the Internet, more than one-fourth (n=85; 29%) used computers daily, and >30% (n=96; 33%) never accessed the Internet. In total, approximately one-fourth of them (n=134; 25%) learned to use computers, and less than one-third of them (n=143; 31%) were known to use the Internet by themselves. Older people (aged 45-65 years) and those with less years of education (primary school) tended not to use the computers and the Internet at all (Pcomputers and the Internet, and they mainly used the Internet to seek information. Social, occupational, and psychological functioning (which were evaluated with Global Assessment of Functioning) were not associated with access to and frequency of computer and the Internet use. The results support the use of computers and the Internet as part of clinical work in mental health care.

  10. Connectivity to computers and the Internet among patients with schizophrenia spectrum disorders: a cross-sectional study

    Science.gov (United States)

    Välimäki, Maritta; Kuosmanen, Lauri; Hätönen, Heli; Koivunen, Marita; Pitkänen, Anneli; Athanasopoulou, Christina; Anttila, Minna

    2017-01-01

    Purpose Information and communication technologies have been developed for a variety of health care applications and user groups in the field of health care. This study examined the connectivity to computers and the Internet among patients with schizophrenia spectrum disorders (SSDs). Patients and methods A cross-sectional survey design was used to study 311 adults with SSDs from the inpatient units of two psychiatric hospitals in Finland. The data collection lasted for 20 months and was done through patients’ medical records and a self-reported, structured questionnaire. Data analysis included descriptive statistics. Results In total, 297 patients were included in this study (response rate =96%). More than half of them (n=156; 55%) had a computer and less than half of them (n=127; 44%) had the Internet at home. Of those who generally had access to computers and the Internet, more than one-fourth (n=85; 29%) used computers daily, and >30% (n=96; 33%) never accessed the Internet. In total, approximately one-fourth of them (n=134; 25%) learned to use computers, and less than one-third of them (n=143; 31%) were known to use the Internet by themselves. Older people (aged 45–65 years) and those with less years of education (primary school) tended not to use the computers and the Internet at all (Pcomputers and the Internet, and they mainly used the Internet to seek information. Social, occupational, and psychological functioning (which were evaluated with Global Assessment of Functioning) were not associated with access to and frequency of computer and the Internet use. The results support the use of computers and the Internet as part of clinical work in mental health care. PMID:28490882

  11. The connected brain

    NARCIS (Netherlands)

    van den Heuvel, M.P.

    2009-01-01

    The connected brain Martijn van den Heuvel, 2009 Our brain is a network. It is a network of different brain regions that are all functionally and structurally linked to each other. In the past decades, neuroimaging studies have provided a lot of information about the specific functions of each separ

  12. Preschool Connected Speech Inventory.

    Science.gov (United States)

    DiJohnson, Albert; And Others

    This speech inventory developed for a study of aurally handicapped preschool children (see TM 001 129) provides information on intonation patterns in connected speech. The inventory consists of a list of phrases and simple sentences accompanied by pictorial clues. The test is individually administered by a teacher-examiner who presents the spoken…

  13. Preschool Connected Speech Inventory.

    Science.gov (United States)

    DiJohnson, Albert; And Others

    This speech inventory developed for a study of aurally handicapped preschool children (see TM 001 129) provides information on intonation patterns in connected speech. The inventory consists of a list of phrases and simple sentences accompanied by pictorial clues. The test is individually administered by a teacher-examiner who presents the spoken…

  14. Expressed breast milk as 'connection' and its influence on the construction of 'motherhood' for mothers of preterm infants: a qualitative study

    Directory of Open Access Journals (Sweden)

    Sweet Linda

    2008-12-01

    Full Text Available Abstract Background Breast milk is considered the optimal nutrition for all newborn infants. While there is high initiation of lactation among mothers of preterm infants in Australia, there is a rapid decline of continued lactation. Furthermore, there is an inverse relationship between infant gestation and duration of lactation. To better understand the breastfeeding experience of parents of very low birth weight (VLBW preterm infants an interpretive phenomenological study was conducted. Methods This longitudinal study was conducted using an interpretive phenomenological approach. Data were collected from 17 parents through 45 individual interviews with both mothers and fathers, from birth to 12 months of age. This data was then transcribed verbatim and analysed using thematic analysis. Results The analysis identified six primary themes: the intention to breastfeed naturally; breast milk as connection; the maternal role of breast milk producer; breast milk as the object of attention; breastfeeding and parenting the hospitalised baby and the demise of breastfeeding. This paper reports on the theme of 'breast milk as connection'. Providing expressed breast milk offered one way the mothers could be physiologically and emotionally connected to their preterm infant while they were in the constant care of hospital staff. Indeed, breast milk was considered the only way the new mother could connect her body (or part there of to her preterm baby in hospital. This sense of connection however, comes at a cost. On the one hand, the breast milk offers a feeling of connection to the baby, but, on the other, this connection comes only after disconnection of the mother and baby and – through breast expression – mother and her milk. This ability of breast milk to connect mother and baby makes the expressed breast milk highly valued, and places unexpected pressure on the mother to produce milk as integral to her sense of motherhood. Conclusion The findings of

  15. Altered effective connectivity network of the basal ganglia in low-grade hepatic encephalopathy: a resting-state fMRI study with Granger causality analysis.

    Directory of Open Access Journals (Sweden)

    Rongfeng Qi

    Full Text Available BACKGROUND: The basal ganglia often show abnormal metabolism and intracranial hemodynamics in cirrhotic patients with hepatic encephalopathy (HE. Little is known about how the basal ganglia affect other brain system and is affected by other brain regions in HE. The purpose of this study was to investigate whether the effective connectivity network associated with the basal ganglia is disturbed in HE patients by using resting-state functional magnetic resonance imaging (rs-fMRI. METHODOLOGY/PRINCIPAL FINDINGS: Thirty five low-grade HE patients and thirty five age- and gender- matched healthy controls participated in the rs-fMRI scans. The effective connectivity networks associated with the globus pallidus, the primarily affected region within basal ganglia in HE, were characterized by using the Granger causality analysis and compared between HE patients and healthy controls. Pearson correlation analysis was performed between the abnormal effective connectivity and venous blood ammonia levels and neuropsychological performances of all HE patients. Compared with the healthy controls, patients with low-grade HE demonstrated mutually decreased influence between the globus pallidus and the anterior cingulate cortex (ACC, cuneus, bi-directionally increased influence between the globus pallidus and the precuneus, and either decreased or increased influence from and to the globus pallidus in many other frontal, temporal, parietal gyri, and cerebellum. Pearson correlation analyses revealed that the blood ammonia levels in HE patients negatively correlated with effective connectivity from the globus pallidus to ACC, and positively correlated with that from the globus pallidus to precuneus; and the number connectivity test scores in patients negatively correlated with the effective connectivity from the globus pallidus to ACC, and from superior frontal gyrus to globus pallidus. CONCLUSIONS/SIGNIFICANCE: Low-grade HE patients had disrupted effective

  16. Structural and functional connectivity of the human brain in autism spectrum disorders and attention-deficit/hyperactivity disorder: A rich club organization study

    Science.gov (United States)

    Ray, Siddharth; Miller, Meghan; Karalunas, Sarah; Robertson, C.J.; Grayson, David; Cary, Paul; Hawkey, Elizabeth; Painter, Julia G.; Kriz, Daniel; Fombonne, Eric; Nigg, Joel T.; Fair, Damien A.

    2015-01-01

    Attention deficit hyperactive disorder (ADHD) and Autism spectrum disorders (ASD) are two of the most common and vexing neurodevelopmental disorders among children. Although the two disorders share many behavioral and neuropsychological characteristics, most MRI studies examine only one of the disorders at a time. Using graph theory combined with structural and functional connectivity, we examined the large-scale network organization among three groups of children: a group with ADHD (8-12 years, n = 20), a group with ASD (7-13 years, n = 16), and typically developing controls (TD) (8-12 years, n = 20). We apply the concept of the rich-club organization, whereby central, highly connected hub regions are also highly connected to themselves. We examine the brain into two different network domains: (1) inside a rich-club network phenomena, and (2) outside a rich-club network phenomena. ASD and ADHD populations had markedly different patterns of rich club and non rich-club connections in both functional and structural data. The ASD group exhibited higher connectivity in structural and functional networks but only inside the rich-club networks. These findings were replicated using the autism brain imaging data exchange (ABIDE) dataset with ASD (n = 85) and TD (n = 101). The ADHD group exhibited a lower generalized fractional anisotropy (GFA) and functional connectivity inside the rich-club networks, but a higher number of axonal fibers and correlation coefficient values outside the rich-club. Despite some shared biological features and frequent comorbity, these data suggest ADHD and ASD exhibit distinct large-scale connectivity patterns in middle childhood. PMID:25116862

  17. A theory for bone resorption based on the local rupture of osteocytes cells connections: A finite element study.

    Science.gov (United States)

    Ridha, Hambli; Almitani, Khalid H; Chamekh, Abdessalem; Toumi, Hechmi; Tavares, Joao Manuel R S

    2015-04-01

    In this work, a bone damage resorption finite element model based on the disruption of the inhibitory signal transmitted between osteocytes cells in bone due to damage accumulation is developed and discussed. A strain-based stimulus function coupled to a damage-dependent spatial function is proposed to represent the connection between two osteocytes embedded in the bone tissue. The signal is transmitted to the bone surface to activate bone resorption. The proposed model is based on the idea that the osteocyte signal reduction is not related to the reduction of the stimulus sensed locally by osteocytes due to damage, but to the difficulties for the signal in travelling along a disrupted area due to microcracks that can destroy connections of the intercellular network between osteocytes and bone-lining cells. To check the potential of the proposed model to predict the damage resorption process, two bone resorption mechano-regulation rules corresponding to two mechanotransduction approaches have been implemented and tested: (1) Bone resorption based on a coupled strain-damage stimulus function without ruptured osteocyte connections (NROC); and (2) Bone resorption based on a strain stimulus function with ruptured osteocyte connections (ROC). The comparison between the results obtained by both models, shows that the proposed model based on ruptured osteocytes connections predicts realistic results in conformity with previously published findings concerning the fatigue damage repair in bone.

  18. Studies on synthesis and activation mechanism of mitomycin dimers connected by 1,2-dithiolane and diol linkers.

    Science.gov (United States)

    Kim, Hyoung Rae; Kim, Jae Jin; Park, Jung Jae; Lee, Sang Hyup

    2012-10-01

    We report the synthetic and mechanistic studies on a new cyclic disulfide mitomycin dimer, 7-N,7'-N'-(1″,2″-dithiolanyl-3″,5″-dimethylenyl)bismitomycin C (8), and a diol mitomycin dimer, 7-N,7'-N'-(2″,4″-dihydroxy-1″,5″-pentanediyl)bismitomycin C (9). Mitomycin 8 is a dimer connected by a 1,2-dithiolane (a five-membered cyclic disulfide) linker, and was specifically designed to undergo nucleophilic activation and double DNA alkylations leading to efficient production of DNA interstrand cross-link (DNA ISC) adducts. Disulfide cleavage in 8 would generate two thiol groups that could serve as probes to activate two mitomycin rings. At first, the target mitomycin 8 was synthesized using mitomycin A (1) and the key intermediate, cyclic disulfide (10), which was prepared through a seven-step synthetic sequence. Diol mitomycin 9 was also synthesized from 1 and diamine salt 13. Next, kinetic studies using solvolysis reaction revealed that the activation rates of 8 were much higher than those of 9 and mitomycin C (2) under nucleophilic conditions provided by Et(3)P presumably due to the presence of a cyclic disulfide unit in 8. These findings led us to propose a nucleophilic activation pathway for 8. Then, DNA ISC experiments further revealed that the levels of DNA ISC caused by 8 in the presence of Et(3)P were much higher (97%) than those by 9 (5%) and 2 (4%). More importantly, mitomycin 8 underwent much faster activation and produced slightly higher levels of DNA ISC than the previously reported mitomycins 5-7. Overall, we concluded that 8 was highly efficient for both nucleophilic activation and corresponding DNA ISC formation, and that this differentiation came from the crucial function of the cyclic disulfide unit in 8.

  19. Distributed Generation and Islanding – Study on Converter Modeling of PV Grid-Connected Systems under Islanding Phenomena

    OpenAIRE

    2010-01-01

    The technique to derive a dc-ac full bridge switching converter for a PV grid-connected system are proposed in this paper. An analysis of islanding phenomena due to load variations of R and RLC connections can be easily derived by using the state-space averaging technique and the piecewise technique with feedback current control by setting up the duty cycle with sinusoidal terms around constant value of 0.5. The solution of the two proposed models can be handled via MATLAB/SIMULINK in fast sp...

  20. Connection Strings Property on ADO Connection Object

    Institute of Scientific and Technical Information of China (English)

    Girigi Deogratias; Wu Min; Cao Weihua

    2002-01-01

    The connection string property on ADO connection object contains the information used to establish a connection to the data source. The syntax, the keyword of that information must be in specific format. Depending on the type of data you are connecting to, you need either specify an OLEDB provider or use on ODBC driver. The biggest problem, the industries face is the proliferation of data access interfaces, and the complexity of creating,maintaining and programming against them, and the network problem when communicating over the Intranet or the Internet. This paper first provides an in-depth look of the standard arguments supported by ADO connection string; then gives the easier way for understanding the meaning, the utility and the syntax of the connection strings property on ADO connection object, and finally proposes solution to work around the problems due to the connection strings errors.

  1. Aberrant EEG functional connectivity and EEG power spectra in resting state post-traumatic stress disorder: a sLORETA study.

    Science.gov (United States)

    Imperatori, Claudio; Farina, Benedetto; Quintiliani, Maria Isabella; Onofri, Antonio; Castelli Gattinara, Paola; Lepore, Marta; Gnoni, Valentina; Mazzucchi, Edoardo; Contardi, Anna; Della Marca, Giacomo

    2014-10-01

    The aim of the present study was to explore the modifications of EEG power spectra and EEG connectivity of resting state (RS) condition in patients with post-traumatic stress disorder (PTSD). Seventeen patients and seventeen healthy subjects matched for age and gender were enrolled. EEG was recorded during 5min of RS. EEG analysis was conducted by means of the standardized Low Resolution Electric Tomography software (sLORETA). In power spectra analysis PTSD patients showed a widespread increase of theta activity (4.5-7.5Hz) in parietal lobes (Brodmann Area, BA 7, 4, 5, 40) and in frontal lobes (BA 6). In the connectivity analysis PTSD patients also showed increase of alpha connectivity (8-12.5Hz) between the cortical areas explored by Pz-P4 electrode. Our results could reflect the alteration of memory systems and emotional processing consistently altered in PTSD patients.

  2. Formal connections in deformation quantization

    DEFF Research Database (Denmark)

    Masulli, Paolo

    attention on symplectic manifolds equipped with a family of star products, indexed by a parameter space. In this situation we can define a connection in the trivial bundle over the parameter space with fibres the formal smooth functions on the manifold, which relates the star products in the family...... and is called a formal connection. We study the question of classifying such formal connections. To each star product we can associate a certain cohomology class called the characteristic class. It turns out that a formal connection exists if and only if all the star products in the family have the same...... characteristic class, and that formal connections form an affine space over the derivations of the star products. Moreover, if the parameter space for the family of star products is contractible, we obtain that any two flat formal connections are gauge equivalent via a self-equivalence of the family of star...

  3. A Study of the Pelagic Larval Duration of Acropora humilis, Coral Recruitment and Connectivity in the Saudi Arabian Red Sea

    KAUST Repository

    Khalil, Maha

    2011-12-12

    Combined knowledge of the pelagic larval duration of coral species and coral recruitment patterns can provide evidence of inter-reef connectivity and indicate a reef’s ability to recover. We attempted to determine the maximum pelagic larval duration of Acropora humilis. Larvae were reared in a controlled environment unfavorable for settlement. The larvae lived in a pelagic state for a maximum of 29 days, although this is probably an underestimate of actual longevity for this species. Given the information available from the literature with respect to larval dispersal rates, it is not expected that larvae with this longevity will disperse further than 10-20 km from their natal reef, if at all. A long-term recruitment monitoring project was also set up on Abu Shosha Reef, which suffered nearly complete coral loss due to a bleaching event in summer of 2010. In April 2011, 60 settlement plates were placed on the reef. In July, a total of 102 living scleractinian recruits were counted on the plates. While pocilloporids were the most dominant recruits on the reef (57.8%), about 20.6% of living recruits belonged to Acroporidae, a family whose live cover on the reef is extremely low (0.67%). However, the overall mean density of recruits was very low (1.7 living recruits/100cm2) compared to similar studies around the world despite the spawning season having just ended. Fish surveys showed herbivore biomass to be very low compared to other reef systems in the world, but densities were significantly higher than another reef in the Red Sea with about 10 times more live coral cover. Recovery from bleaching for Abu Shosha and similar reefs in the region may be very slow relative to rates observed in other parts of the world if recruitment rates and herbivore communities remain low.

  4. Functional connectivity in tactile object discrimination: a principal component analysis of an event related fMRI-Study.

    Directory of Open Access Journals (Sweden)

    Susanne Hartmann

    Full Text Available BACKGROUND: Tactile object discrimination is an essential human skill that relies on functional connectivity between the neural substrates of motor, somatosensory and supramodal areas. From a theoretical point of view, such distributed networks elude categorical analysis because subtraction methods are univariate. Thus, the aim of this study was to identify the neural networks involved in somatosensory object discrimination using a voxel-based principal component analysis (PCA of event-related functional magnetic resonance images. METHODOLOGY/PRINCIPAL FINDINGS: Seven healthy, right-handed subjects aged between 22 and 44 years were required to discriminate with their dominant hand the length differences between otherwise identical parallelepipeds in a two-alternative forced-choice paradigm. Of the 34 principal components retained for analysis according to the 'bootstrapped' Kaiser-Guttman criterion, t-tests applied to the subject-condition expression coefficients showed significant mean differences between the object presentation and inter-stimulus phases in PC 1, 3, 26 and 32. Specifically, PC 1 reflected object exploration or manipulation, PC 3 somatosensory and short-term memory processes. PC 26 evinced the perception that certain parallelepipeds could not be distinguished, while PC 32 emerged in those choices when they could be. Among the cerebral regions evident in the PCs are the left posterior parietal lobe and premotor cortex in PC 1, the left superior parietal lobule (SPL and the right cuneus in PC 3, the medial frontal and orbitofrontal cortex bilaterally in PC 26, and the right intraparietal sulcus, anterior SPL and dorsolateral prefrontal cortex in PC 32. CONCLUSIONS/SIGNIFICANCE: The analysis provides evidence for the concerted action of large-scale cortico-subcortical networks mediating tactile object discrimination. Parallel to activity in nodes processing object-related impulses we found activity in key cerebral regions

  5. Association of cerebral networks in resting state with sexual preference of homosexual men: a study of regional homogeneity and functional connectivity.

    Directory of Open Access Journals (Sweden)

    Shaohua Hu

    Full Text Available Recent imaging studies have shown that brain morphology and neural activity during sexual arousal differ between homosexual and heterosexual men. However, functional differences in neural networks at the resting state is unknown. The study is to characterize the association of homosexual preference with measures of regional homogeneity and functional connectivity in the resting state. Participants were 26 healthy homosexual men and 26 age-matched healthy heterosexual men in whom we collected echo planar magnetic resonance imaging data in the resting state. The sexual orientation was evaluated using the Kinsey Scale. We first assessed group differences in regional homogeneity and then, taking the identified differences as seed regions, we compared groups in measures of functional connectivity from those seeds. The behavioral significances of the differences in regional homogeneity and functional connectivity were assessed by examining their associations with Kinsey Scores. Homosexual participants showed significantly reduced regional homogeneity in the left inferior occipital gyrus, right middle occipital gyrus, right superior occipital gyrus, left cuneus, right precuneus, and increased regional homogeneity in rectal gyrus, bilateral midbrain, and left temporal lobe. Regional homogeneity correlated positively with Kinsey scores in the left inferior occipital gyrus. The homosexual group also showed reduced functional connectivity between left middle temporal gyrus, left supra-marginal gyrus, right cuneus and the seed region, i.e. left inferior occipital gyrus. Additionly, the connection between the left inferior occipital gyrus and right thalamus correlated positively with Kinsey scores. These differences in regional homogeneity and functional connectivity may contribute to a better understanding of the neural basis of male sexual orientation.

  6. A nationwide study of connective tissue disease and other rheumatic conditions among Danish women with long-term cosmetic breast implantation

    DEFF Research Database (Denmark)

    Fryzek, Jon P; Holmich, Lisbet; McLaughlin, Joseph K

    2007-01-01

    PURPOSE: Numerous epidemiologic studies have demonstrated that breast implants are not associated with connective tissue diseases (CTDs). However, many CTDs are rare, and continued follow-up of women with breast implants is warranted. METHODS: We extended by 5 years the follow-up of our earlier...

  7. A Case Study on the Impacts of Connective Technology on Self-Efficacy and Self-Regulated Learning of Female Adult Students Managing Work-Life Balance

    Science.gov (United States)

    Sheetz, Tracey L.

    2014-01-01

    Adults frequently define their lives as "hectic" and "overextended;" yet, many make the decision to return to school and add the role of student into their busy lives. This research study explored and explained the impact of connective technology on self-efficacy and self-regulated learning of female adult students balancing…

  8. Minimum cost connection networks

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Tvede, Mich

    In the present paper we consider the allocation of cost in connection networks. Agents have connection demands in form of pairs of locations they want to be connected. Connections between locations are costly to build. The problem is to allocate costs of networks satisfying all connection demands...

  9. Attribute-space connectivity and connected filters

    NARCIS (Netherlands)

    Wilkinson, Michael H.F.

    2007-01-01

    In this paper connected operators from mathematical morphology are extended to a wider class of operators, which are based on connectivities in higher dimensional spaces, similar to scale spaces, which will be called attribute-spaces. Though some properties of connected filters are lost, granulometr

  10. The Argumentative Connective "Meme" in French: An Experimental Study in Eight- to Ten-Year-Old Children.

    Science.gov (United States)

    Bassano, Dominique; Champaud, Christian

    1989-01-01

    Examines how children understand the argumentative function of the French connective meme (even). Two completion tasks, related to the argumentative properties of the morpheme, were used: 1) to infer the conclusion of an "even" sentence, and 2) to infer the argument position. (34 references) (Author/CB)

  11. Incidence of Connected Consciousness after Tracheal Intubation A Prospective, International, Multicenter Cohort Study of the Isolated Forearm Technique

    NARCIS (Netherlands)

    Sanders, Robert D.; Gaskell, Amy; Raz, Aeyal; Winders, Joel; Stevanovic, Ana; Rossaint, Rolf; Boncyk, Christina; Defresne, Aline; Tran, Gabriel; Tasbihgou, Seth; Meier, Sascha; Vlisides, Phillip E.; Fardous, Hussein; Hess, Aaron; Bauer, Rebecca M.; Absalom, Anthony; Mashour, George A.; Bonhomme, Vincent; Coburn, Mark; Sleigh, Jamie

    Background: The isolated forearm technique allows assessment of consciousness of the external world (connected consciousness) through a verbal command to move the hand (of a tourniquet-isolated arm) during intended general anesthesia. Previous isolated forearm technique data suggest that the

  12. Studying Plant-Rhizobium Mutualism in the Biology Classroom: Connecting the Big Ideas in Biology through Inquiry

    Science.gov (United States)

    Suwa, Tomomi; Williamson, Brad

    2014-01-01

    We present a guided-inquiry biology lesson, using the plant-rhizobium symbiosis as a model system. This system provides a rich environment for developing connections between the big ideas in biology as outlined in the College Board's new AP Biology Curriculum. Students gain experience with the practice of scientific investigation, from…

  13. Incidence of Connected Consciousness after Tracheal Intubation : A Prospective, International, Multicenter Cohort Study of the Isolated Forearm Technique

    NARCIS (Netherlands)

    Sanders, Robert; Gaskell, Amy; Raz, Aeyal; Winders, Joel; Stevanovic, Ana; Rossaint, Rolf; Boncyk, Christina; Defresne, Aline; Tran, Gabriel; Tasbihgou, Seth; Meier, Sascha; Vlisides, Phillip E; Fardous, Hussein; Hess, Aaron; Bauer, Rebecca M; Absalom, Anthony; Mashour, George A; Bonhomme, Vincent; Coburn, Mark; Sleigh, Jamie

    2016-01-01

    BACKGROUND: The isolated forearm technique allows assessment of consciousness of the external world (connected consciousness) through a verbal command to move the hand (of a tourniquet-isolated arm) during intended general anesthesia. Previous isolated forearm technique data suggest that the inciden

  14. Studying Plant-Rhizobium Mutualism in the Biology Classroom: Connecting the Big Ideas in Biology through Inquiry

    Science.gov (United States)

    Suwa, Tomomi; Williamson, Brad

    2014-01-01

    We present a guided-inquiry biology lesson, using the plant-rhizobium symbiosis as a model system. This system provides a rich environment for developing connections between the big ideas in biology as outlined in the College Board's new AP Biology Curriculum. Students gain experience with the practice of scientific investigation, from…

  15. The Argumentative Connective "Meme" in French: An Experimental Study in Eight- to Ten-Year-Old Children.

    Science.gov (United States)

    Bassano, Dominique; Champaud, Christian

    1989-01-01

    Examines how children understand the argumentative function of the French connective meme (even). Two completion tasks, related to the argumentative properties of the morpheme, were used: 1) to infer the conclusion of an "even" sentence, and 2) to infer the argument position. (34 references) (Author/CB)

  16. Perceived connections between information and communication technology use and mental symptoms among young adults - a qualitative study

    Directory of Open Access Journals (Sweden)

    Hagberg Mats

    2010-02-01

    Full Text Available Abstract Background Prospective associations have been found between high use of information and communication technology (ICT and reported mental symptoms among young adult university students, but the causal mechanisms are unclear. Our aim was to explore possible explanations for associations between high ICT use and symptoms of depression, sleep disorders, and stress among young adults in order to propose a model of possible pathways to mental health effects that can be tested epidemiologically. Methods We conducted a qualitative interview study with 16 women and 16 men (21-28 years, recruited from a cohort of university students on the basis of reporting high computer (n = 28 or mobile phone (n = 20 use at baseline and reporting mental symptoms at the one-year follow-up. Semi-structured interviews were performed, with open-ended questions about possible connections between the use of computers and mobile phones, and stress, depression, and sleep disturbances. The interview data were analyzed with qualitative content analysis and summarized in a model. Results Central factors appearing to explain high quantitative ICT use were personal dependency, and demands for achievement and availability originating from the domains of work, study, social life, and individual aspirations. Consequences included mental overload, neglect of other activities and personal needs, time pressure, role conflicts, guilt feelings, social isolation, physical symptoms, worry about electromagnetic radiation, and economic problems. Qualitative aspects (destructive communication and information were also reported, with consequences including vulnerability, misunderstandings, altered values, and feelings of inadequacy. User problems were a source of frustration. Altered ICT use as an effect of mental symptoms was reported, as well as possible positive effects of ICT on mental health. Conclusions The concepts and ideas of the young adults with high ICT use and mental

  17. Connectivity to computers and the Internet among patients with schizophrenia spectrum disorders: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Välimäki M

    2017-04-01

    Full Text Available Maritta Välimäki,1–3 Lauri Kuosmanen,1,4,5 Heli Hätönen,1 Marita Koivunen,1,6 Anneli Pitkänen,7 Christina Athanasopoulou,1 Minna Anttila1 1Department of Nursing Science, Faculty of Medicine, University of Turku, Finland; 2Development Unit, Turku University Hospital, Turku, Finland; 3School of Nursing, Hong Kong Polytechnic University, Kowloon, Hong Kong, SAR, China; 4University of Helsinki and Helsinki University Hospital, Helsinki, Finland; 5Social and Healthcare Department, City of Vantaa, Vantaa, Finland; 6Administrative Centre, Research and Development, Satakunta Hospital District, Pori, Finland; 7Administration Centre, Pirkanmaa Hospital District, Tampere, Finland Purpose: Information and communication technologies have been developed for a variety of health care applications and user groups in the field of health care. This study examined the connectivity to computers and the Internet among patients with schizophrenia spectrum disorders (SSDs.Patients and methods: A cross-sectional survey design was used to study 311 adults with SSDs from the inpatient units of two psychiatric hospitals in Finland. The data collection lasted for 20 months and was done through patients’ medical records and a self-reported, structured questionnaire. Data analysis included descriptive statistics.Results: In total, 297 patients were included in this study (response rate =96%. More than half of them (n=156; 55% had a computer and less than half of them (n=127; 44% had the Internet at home. Of those who generally had access to computers and the Internet, more than one-fourth (n=85; 29% used computers daily, and >30% (n=96; 33% never accessed the Internet. In total, approximately one-fourth of them (n=134; 25% learned to use computers, and less than one-third of them (n=143; 31% were known to use the Internet by themselves. Older people (aged 45–65 years and those with less years of education (primary school tended not to use the computers and the

  18. Interhemispheric functional connectivity and its relationships with clinical characteristics in major depressive disorder: a resting state fMRI study.

    Directory of Open Access Journals (Sweden)

    Li Wang

    Full Text Available BACKGROUND: Abnormalities in large-scale, structural and functional brain connectivity have been increasingly reported in patients with major depressive disorder (MDD. However, MDD-related alterations in functional interaction between the cerebral hemispheres are still not well understood. Resting state fMRI, which reveals spontaneous neural fluctuations in blood oxygen level dependent signals, provides a means to detect interhemispheric functional coherence. We examined the resting state functional connectivity (RSFC between the two hemispheres and its relationships with clinical characteristics in MDD patients using a recently proposed measurement named "voxel-mirrored homotopic connectivity (VMHC". METHODOLOGY/PRINCIPAL FINDINGS: We compared the interhemispheric RSFC, computed using the VMHC approach, of seventeen first-episode drug-naive patients with MDD and seventeen healthy controls. Compared to the controls, MDD patients showed significant VMHC decreases in the medial orbitofrontal gyrus, parahippocampal gyrus, fusiform gyrus, and occipital regions including the middle occipital gyrus and cuneus. In MDD patients, a negative correlation was found between VMHC of the fusiform gyrus and illness duration. Moreover, there were several regions whose VMHC showed significant negative correlations with the severity of cognitive disturbance, including the prefrontal regions, such as middle and inferior frontal gyri, and two regions in the cereballar crus. CONCLUSIONS/SIGNIFICANCE: These findings suggest that the functional coordination between homotopic brain regions is impaired in MDD patients, thereby providing new evidence supporting the interhemispheric connectivity deficits of MDD. The significant correlations between the VMHC and clinical characteristics in MDD patients suggest potential clinical implication of VMHC measures for MDD. Interhemispheric RSFC may serve as a useful screening method for evaluating MDD where neural connectivity is

  19. Structural Brain Connectivity Constrains within-a-Day Variability of Direct Functional Connectivity

    Directory of Open Access Journals (Sweden)

    Bumhee Park

    2017-08-01

    Full Text Available The idea that structural white matter connectivity constrains functional connectivity (interactions among brain regions has widely been explored in studies of brain networks; studies have mostly focused on the “average” strength of functional connectivity. The question of how structural connectivity constrains the “variability” of functional connectivity remains unresolved. In this study, we investigated the variability of resting state functional connectivity that was acquired every 3 h within a single day from 12 participants (eight time sessions within a 24-h period, 165 scans per session. Three different types of functional connectivity (functional connectivity based on Pearson correlation, direct functional connectivity based on partial correlation, and the pseudo functional connectivity produced by their difference were estimated from resting state functional magnetic resonance imaging data along with structural connectivity defined using fiber tractography of diffusion tensor imaging. Those types of functional connectivity were evaluated with regard to properties of structural connectivity (fiber streamline counts and lengths and types of structural connectivity such as intra-/inter-hemispheric edges and topological edge types in the rich club organization. We observed that the structural connectivity constrained the variability of direct functional connectivity more than pseudo-functional connectivity and that the constraints depended strongly on structural connectivity types. The structural constraints were greater for intra-hemispheric and heterologous inter-hemispheric edges than homologous inter-hemispheric edges, and feeder and local edges than rich club edges in the rich club architecture. While each edge was highly variable, the multivariate patterns of edge involvement, especially the direct functional connectivity patterns among the rich club brain regions, showed low variability over time. This study suggests that

  20. Wireless Connectivity and Capacity

    CERN Document Server

    Halldorsson, Magnus M

    2011-01-01

    Given $n$ wireless transceivers located in a plane, a fundamental problem in wireless communications is to construct a strongly connected digraph on them such that the constituent links can be scheduled in fewest possible time slots, assuming the SINR model of interference. In this paper, we provide an algorithm that connects an arbitrary point set in $O(\\log n)$ slots, improving on the previous best bound of $O(\\log^2 n)$ due to Moscibroda. This is complemented with a super-constant lower bound on our approach to connectivity. An important feature is that the algorithms allow for bi-directional (half-duplex) communication. One implication of this result is an improved bound of $\\Omega(1/\\log n)$ on the worst-case capacity of wireless networks, matching the best bound known for the extensively studied average-case. We explore the utility of oblivious power assignments, and show that essentially all such assignments result in a worst case bound of $\\Omega(n)$ slots for connectivity. This rules out a recent cla...

  1. Altered functional connectivity in posttraumatic stress disorder with versus without comorbid major depressive disorder: a resting state fMRI study.

    Science.gov (United States)

    Kennis, Mitzy; Rademaker, Arthur R; van Rooij, Sanne J H; Kahn, René S; Geuze, Elbert

    2013-01-01

    Posttraumatic stress disorder (PTSD) is an anxiety disorder that is often diagnosed with comorbid depressive disorder. Therefore, neuroimaging studies investigating PTSD typically include both patients with and without comorbid depression. Differences in activity of the anterior cingulate cortex (ACC) and insula have been shown to differentiate PTSD patients with and without major depressive disorder (MDD). Whether or not comorbid MDD affects resting state functional connectivity of PTSD patients has not been investigated to our knowledge. Here, resting state functional connectivity of PTSD patients with (PTSD+MDD; n=27) and without (PTSD-MDD; n=23) comorbid MDD was investigated. The subgenual ACC and insula were investigated as seed regions. Connectivity between the subgenual ACC and perigenual parts of the ACC was increased in PTSD+MDD versus PTSD-MDD, which may reflect the presence of depressive specific symptoms such as rumination. Functional connectivity of the subgenual ACC with the thalamus was reduced, potentially related to more severe deficits in executive functioning in the PTSD+MDD group versus the PTSD-MDD group. In addition, the PTSD+MDD group showed reduced functional connectivity of the insula with the hippocampus compared to the PTSD-MDD group. However, this cluster was no longer significantly different when PTSD patients that were using medication were excluded from analyses. Thus, resting state functional connectivity of the subgenual ACC can distinguish PTSD+MDD from PTSD-MDD, and this may therefore be used as a neurobiological marker for comorbid MDD in the presence of PTSD. As PTSD+MDD are more treatment resistant, these findings can also guide treatment development, for example by targeting the subgenual ACC network with treatment.

  2. Association of creative achievement with cognitive flexibility by a combined voxel-based morphometry and resting-state functional connectivity study.

    Science.gov (United States)

    Chen, Qunlin; Yang, Wenjing; Li, Wenfu; Wei, Dongtao; Li, Haijiang; Lei, Qiao; Zhang, Qinglin; Qiu, Jiang

    2014-11-15

    Although researchers generally concur that creativity involves the production of novel and useful products, the neural basis of creativity remains elusive due to the complexity of the cognitive processes involved. Recent studies have shown that highly creative individuals displayed more cognitive flexibility. However, direct evidence supporting the relationship between creativity and cognitive flexibility has rarely been investigated using both structural and functional neuroimaging techniques. We used a combined voxel-based morphometry and resting-state functional connectivity (rsFC) analysis to investigate the relationship between individual creativity ability assessed by the creative achievement questionnaire (CAQ), and regional gray matter volume (GMV), as well as intrinsic functional connectivity. Results showed that CAQ scores negatively correlated with GMV in the rostral anterior cingulate cortex (ACC) and the bilateral dorsal ACC (dACC) extending to supplementary motor area, but positively correlated with GMV in the bilateral superior frontal gyrus and ventral medial prefrontal cortex (vmPFC). Further functional connectivity analysis revealed that higher creative achievement was inversely associated with the strength of rsFC between the dACC and medial superior frontal gyrus (mSFG), right middle frontal gyrus, and left orbito-frontal insula. Moreover, the association between the dACC-mSFG connectivity and CAQ scores was mediated by cognitive flexibility, assessed by a task-switching paradigm. These findings indicate that individual differences in creative achievement are associated with both brain structure and corresponding intrinsic functional connectivity involved in cognitive flexibility and deliberate creative processing. Furthermore, dACC-mSFG connectivity may affect creative achievement through its impact on cognitive flexibility.

  3. Undifferentiated Connective Tissue Disease

    Science.gov (United States)

    ... Home Conditions Undifferentiated Connective Tissue Disease (UCTD) Undifferentiated Connective Tissue Disease (UCTD) Make an Appointment Find a Doctor ... L. Goldstein, MD, MMSc (February 01, 2016) Undifferentiated connective tissue disease (UCTD) is a systemic autoimmune disease. This ...

  4. Connective Tissue Disorders

    Science.gov (United States)

    Connective tissue is the material inside your body that supports many of its parts. It is the "cellular ... their work. Cartilage and fat are examples of connective tissue. There are over 200 disorders that impact connective ...

  5. Minimum cost connection networks

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Tvede, Mich

    . We use three axioms to characterize allocation rules that truthfully implement cost minimizing networks satisfying all connection demands in a game where: (1) a central planner announces an allocation rule and a cost estimation rule; (2) every agent reports her own connection demand as well as all...... connection costs; and, (3) the central planner selects a cost minimizing network satisfying reported connection demands based on estimated connection costs and allocates true connection costs of the selected network....

  6. Effects of DSP4 and dizolcipine on connectivity of solid E19 cortical grafts to ablated SmI region of adult rats; an in vivo electrophysiological study.

    Science.gov (United States)

    Zarei, Mojtaba; Stephenson, John D

    2002-08-30

    The functional connectivity of an embryonic graft implanted into the lesioned somatosensory cortex and the effect of DSP4 (a selective noradrenergic neurotoxin to noradrenergic terminals) and dizolcipine (a non-competitive NMDA receptor antagonist), was studied electrophysiologically. The forepaw representational area of the rat primary somatosensory cortex was lesioned unilaterally and, 3-4 weeks later, tissue from the same region of E19 rat embryos was implanted into the cavity. At 7-9 months later, the rats were anaesthetized and single unit activity was recorded from the grafts in response to contralateral forepaw, ipsilateral hindpaw and contralateral hindpaw stimulation and compared with that obtained in control rats, in rats pretreated with dizolcipine immediately after lesioning and in rats given DSP4 24 h before transplantation. Neurones within the graft were integrated into the host brain and developed a pattern of representation similar to that of intact rats, but with a reduced proportion of neurones exhibiting short-latency response to contralateral forepaw stimulation and an increased proportion responding to stimulation of more than one paw. Pretreatment with dizolcipine did not increase short-latency responses to stimulation of contralateral forepaw stimulation however pretreatment with DSP4 reduced such responses and increased proportion of inhibitory responses. It was concluded that the noradrenergic system plays an important role in establishing host-graft connectivity. The importance of further pharmacological studies on host-graft connectivity and the relation of such connections to neural plasticity were discussed.

  7. Study on the connectivity of heavy oil reservoirs by ultraviolet spectrum technique in the western part of the QHD32-6 oilfield

    Institute of Scientific and Technical Information of China (English)

    XU Yaohui; CHEN Dan

    2008-01-01

    As a new method, the ultraviolet spectrum technique is applied to studying the connectivity of biodegradable heavy oil reservoirs. The similarity of crude oils can be judged according to the extinction coefficient (E)because aromatic hydrocarbons and non-hydrocarbons have conjugated bonds and obvious absorption in the ultraviolet range, and different materials have different characteristics and additives. The relationship diagram is made in terms of the extinction coefficients (E) of the samples by taking E as the Y-axis and wavelength as the X-axis. The connectivity of oil reservoirs is estimated according to the curve positions and characteristic fingerprints of the samples. The connectivity of part of the reservoirs in the western part of the QHD32-6 oilfieid was studied with this method. The results showed that the connectivity of samples from wells F7 and F8 in the Nm-2 oil reservoir zone is good, that of samples from wells F17 and F20 in the Nm-1 oil reservoir zone also is good, and that of samples from wells F17, F19, and F20 is poor.

  8. Introduction aux dynamiques cat\\'egoriques connectives

    CERN Document Server

    Dugowson, Stéphane

    2011-01-01

    This text is a continuation to my former article "On Connectivity Spaces". It takes into account that connectivity spaces gives rise to phenomena which are essentially dynamic. In a first stage, the representation of finite connectivity spaces by links (Brunn-Debrunner-Kanenobu's theorem) leads to the notion of connective representation. But examples of connective representations often come from dynamical systems. And this is even more obvious when we study the adjoint notion of connective foliation. To apply those notions to dynamics, we first need to consider dynamical systems in an unified way. This is done with a categorical point of view on temporalities and dynamics. It is then possible to define categorical connective dynamics, and to apply to them the various connective notions, specially the connectivity order of a connectivity space.

  9. Comparative Study of Standards for Grid-Connected Wind Power Plant in China and the U.S.

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wenzhong; Tian, Tian; Muljadi, Eduard; Zhang, Yincheng; Miller, Mackay; Wang, Weisheng; Wang, Jing

    2015-10-06

    The rapid deployment of wind power has made grid integration and operational issues focal points in industry discussions and research. Compliance with grid connection standards for wind power plants (WPP) is crucial to ensuring the safe and stable operation of the electric power grid. The standards for grid-connected WPPs in China and the United States are compared in this paper to facilitate further improvements to the standards and enhance the development of wind power equipment. Detailed analyses in power quality, low-voltage ride-through capability, active power control, reactive power control, voltage control, and wind power forecasting are provided to enhance the understanding of grid codes in the two largest markets of wind power.

  10. Study on Improving Partial Load by Connecting Geo-thermal Heat Pump System to Fuel Cell Network

    Science.gov (United States)

    Obara, Shinya; Kudo, Kazuhiko

    Hydrogen piping, the electric power line, and exhaust heat recovery piping of the distributed fuel cells are connected with network, and operational planning is carried out. Reduction of the efficiency in partial load is improved by operation of the geo-thermal heat pump linked to the fuel cell network. The energy demand pattern of the individual houses in Sapporo was introduced. And the analysis method aiming at minimization of the fuel rate by the genetic algorithm was described. The fuel cell network system of an analysis example assumed connecting the fuel cell co-generation of five houses. When geo-thermal heat pump was introduced into fuel cell network system stated in this paper, fuel consumption was reduced 6% rather than the conventional method

  11. Convergent Findings of Altered Functional and Structural Brain Connectivity in Individuals with High Functioning Autism: A Multimodal MRI Study.

    Science.gov (United States)

    Mueller, Sophia; Keeser, Daniel; Samson, Andrea C; Kirsch, Valerie; Blautzik, Janusch; Grothe, Michel; Erat, Okan; Hegenloh, Michael; Coates, Ute; Reiser, Maximilian F; Hennig-Fast, Kristina; Meindl, Thomas

    2013-01-01

    Brain tissue changes in autism spectrum disorders seem to be rather subtle and widespread than anatomically distinct. Therefore a multimodal, whole brain imaging technique appears to be an appropriate approach to investigate whether alterations in white and gray matter integrity relate to consistent changes in functional resting state connectivity in individuals with high functioning autism (HFA). We applied diffusion tensor imaging (DTI), voxel-based morphometry (VBM) and resting state functional connectivity magnetic resonance imaging (fcMRI) to assess differences in brain structure and function between 12 individuals with HFA (mean age 35.5, SD 11.4, 9 male) and 12 healthy controls (mean age 33.3, SD 9.0, 8 male). Psychological measures of empathy and emotionality were obtained and correlated with the most significant DTI, VBM and fcMRI findings. We found three regions of convergent structural and functional differences between HFA participants and controls. The right temporo-parietal junction area and the left frontal lobe showed decreased fractional anisotropy (FA) values along with decreased functional connectivity and a trend towards decreased gray matter volume. The bilateral superior temporal gyrus displayed significantly decreased functional connectivity that was accompanied by the strongest trend of gray matter volume decrease in the temporal lobe of HFA individuals. FA decrease in the right temporo-parietal region was correlated with psychological measurements of decreased emotionality. In conclusion, our results indicate common sites of structural and functional alterations in higher order association cortex areas and may therefore provide multimodal imaging support to the long-standing hypothesis of autism as a disorder of impaired higher-order multisensory integration.

  12. Convergent Findings of Altered Functional and Structural Brain Connectivity in Individuals with High Functioning Autism: A Multimodal MRI Study.

    Directory of Open Access Journals (Sweden)

    Sophia Mueller

    Full Text Available Brain tissue changes in autism spectrum disorders seem to be rather subtle and widespread than anatomically distinct. Therefore a multimodal, whole brain imaging technique appears to be an appropriate approach to investigate whether alterations in white and gray matter integrity relate to consistent changes in functional resting state connectivity in individuals with high functioning autism (HFA. We applied diffusion tensor imaging (DTI, voxel-based morphometry (VBM and resting state functional connectivity magnetic resonance imaging (fcMRI to assess differences in brain structure and function between 12 individuals with HFA (mean age 35.5, SD 11.4, 9 male and 12 healthy controls (mean age 33.3, SD 9.0, 8 male. Psychological measures of empathy and emotionality were obtained and correlated with the most significant DTI, VBM and fcMRI findings. We found three regions of convergent structural and functional differences between HFA participants and controls. The right temporo-parietal junction area and the left frontal lobe showed decreased fractional anisotropy (FA values along with decreased functional connectivity and a trend towards decreased gray matter volume. The bilateral superior temporal gyrus displayed significantly decreased functional connectivity that was accompanied by the strongest trend of gray matter volume decrease in the temporal lobe of HFA individuals. FA decrease in the right temporo-parietal region was correlated with psychological measurements of decreased emotionality. In conclusion, our results indicate common sites of structural and functional alterations in higher order association cortex areas and may therefore provide multimodal imaging support to the long-standing hypothesis of autism as a disorder of impaired higher-order multisensory integration.

  13. Effect of Integrated Cognitive Therapy on Hippocampal Functional Connectivity Patterns in Stroke Patients with Cognitive Dysfunction: A Resting-State fMRI Study

    OpenAIRE

    Shanli Yang; Cai Jiang; Haicheng Ye; Jing Tao; Jia Huang; Yanling Gao; Zhicheng Lin; Lidian Chen

    2014-01-01

    Objective. This study aimed to identify abnormal hippocampal functional connectivity (FC) following ischemic stroke using resting-state fMRI. We also explored whether abnormal hippocampal FC could be modulated by integrated cognitive therapy and tested whether these alterations were associated with cognitive performance. Methods. 18 right-handed cognitively impaired ischemic stroke patients and 18 healty control (HC) subjects were included in this study. Stroke subjects were scanned at baseli...

  14. Connecting with Citizens

    DEFF Research Database (Denmark)

    Jørgensen, Poul Erik Flyvholm; Isaksson, Maria

    2017-01-01

    /2007. If Norway, like Denmark, significantly reduces its number of municipalities, the majority of municipalities will undergo significant change and experience loss of identity. Each new municipality will need to create meaningful new identities attractive to publics fearful of alienation inside a community...... they have no relationship to. The study examines how municipalities reach out to connect with their publics, and whether they employ emotional and engaging discourse. Our data consists of 20 Norwegian and 20 Danish municipal websites....

  15. Cocaine addiction related reproducible brain regions of abnormal default-mode network functional connectivity: a group ICA study with different model orders.

    Science.gov (United States)

    Ding, Xiaoyu; Lee, Seong-Whan

    2013-08-26

    Model order selection in group independent component analysis (ICA) has a significant effect on the obtained components. This study investigated the reproducible brain regions of abnormal default-mode network (DMN) functional connectivity related with cocaine addiction through different model order settings in group ICA. Resting-state fMRI data from 24 cocaine addicts and 24 healthy controls were temporally concatenated and processed by group ICA using model orders of 10, 20, 30, 40, and 50, respectively. For each model order, the group ICA approach was repeated 100 times using the ICASSO toolbox and after clustering the obtained components, centrotype-based anterior and posterior DMN components were selected for further analysis. Individual DMN components were obtained through back-reconstruction and converted to z-score maps. A whole brain mixed effects factorial ANOVA was performed to explore the differences in resting-state DMN functional connectivity between cocaine addicts and healthy controls. The hippocampus, which showed decreased functional connectivity in cocaine addicts for all the tested model orders, might be considered as a reproducible abnormal region in DMN associated with cocaine addiction. This finding suggests that using group ICA to examine the functional connectivity of the hippocampus in the resting-state DMN may provide an additional insight potentially relevant for cocaine-related diagnoses and treatments. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. The connective tissue and glial framework in the optic nerve head of the normal human eye: light and scanning electron microscopic studies.

    Science.gov (United States)

    Oyama, Tokuhide; Abe, Haruki; Ushiki, Tatsuo

    2006-12-01

    of the intraocular pressure. The present study has also indicated that glial cells with an astrocytic character play an important role in constructing the connective tissue framework characteristic of the optic nerve head.

  17. [Muscles and connective tissue: histology].

    Science.gov (United States)

    Delage, J-P

    2012-10-01

    Here, we give some comments about the DVD movies "Muscle Attitudes" from Endovivo productions, the movies up lighting some loss in the attention given to studies on the connective tissue, and especially them into muscles. The main characteristics of the different components in the intra-muscular connective tissue (perimysium, endomysium, epimysium) are shown here with special references to their ordered architecture and special references to their spatial distributions. This connective tissue is abundant into the muscles and is in continuity with the muscles in vicinity, with their tendons and their sheath, sticking the whole on skin. This connective tissue has also very abundant connections on the muscles fibres. It is then assumed that the connective tissue sticks every organs or cells of the locomotion system. Considering the elastic properties of the collagen fibres which are the most abundant component of connective tissue, it is possible to up light a panel of connective tissue associated functions such as the transmission of muscle contractions or the regulation of protein and energetic muscles metabolism.

  18. Study on Snubber Circuit of Series Connected IGBT's%IGBT串联阀吸收电路的研究

    Institute of Scientific and Technical Information of China (English)

    范镇淇; 侯凯; 李伟邦

    2013-01-01

    绝缘栅双极型晶体管IGBT综合了GTR和MOSFET的优点,近年来得到了广泛的应用,但是受限于耐压等级,单个IGBT高压大功率电能变换场合还不能满足需求,而串联使用是一种较好的解决方案.在串联使用中为了抑制器件关断过程中产生浪涌过冲,仍然需要吸收电路进行保护.通过对比分析详细阐述了RCD吸收电路在IGBT串联中的使用优势,并给出了参数选取的原则,同时分析了RCD吸收电路对器件动、静态电压均压的影响,并通过实验予以了验证.%Isolate gate bipolar transistor (IGBT) combines the advantage of GTR and MOSFET,which has been widely used in recent years.However,due to the voltage level,single IGBT cannot meet the requirements of highpower power converting.In such application fields,serial connection of IGBT' s is a good solution.In a serial IGBT valve,snubber circuit is indispensable to suppress voltage overshoot while IGBT switching from on state to off state.By analyzing the different snubber circuits,why RCD snubber circuit could be used in IGBT's serial connection was described,and gave the principle of parameter selection.Then investigated how the RCD snubber circuit influenced voltage balance in IGBT 's serial connection,and the results were verified by experiment.

  19. Density functional theory based study of magnetic interaction in bis-oxoverdazyl diradicals connected by different aromatic couplers.

    Science.gov (United States)

    Bhattacharya, Debojit; Misra, Anirban

    2009-05-01

    We design and investigate 11 different bis-oxoverdazyl diradicals connected by various aromatic couplers for their magnetic properties. The intramolecular magnetic exchange coupling constants (J) have been calculated using a broken symmetry approach in DFT framework. The J values are explained using spin polarization maps and magnetic orbitals. Isotropic hyperfine coupling constants (hfcc's) have been calculated for all the species in vacuum. The computed hfcc values also support intramolecular magnetic interactions. It has been found that some of the diradicals have ferromagnetic character while the others are antiferromagnetic in nature.

  20. Changes in behavioural responses to infrastructure affect local and regional connectivity – a simulation study on pond breeding amphibians

    DEFF Research Database (Denmark)

    Pontoppidan, Maj-Britt; Nachman, Gøsta Støger

    2013-01-01

    An extensive and expanding infrastructural network destroys and fragments natural habitat and has detrimental effect on abundance and population viability of many amphibian species. Roads function as barriers in the landscape. They separate local populations from each other or prevent access...... to necessary resources. Therefore, road density and traffic intensity in a region may have severe impact on regional as well as local connectivity. Amphibians may be able to detect and avoid unsuitable habitat. Individuals’ ability to avoid roads can reduce road mortality but at the same time road...

  1. Changes in behavioural responses to infrastructure affect local and regional connectivity – a simulation study on pond breeding amphibians

    DEFF Research Database (Denmark)

    Pontoppidan, Maj-Britt; Nachman, Gøsta Støger

    2013-01-01

    An extensive and expanding infrastructural network destroys and fragments natural habitat and has detrimental effect on abundance and population viability of many amphibian species. Roads function as barriers in the landscape. They separate local populations from each other or prevent access...... to necessary resources. Therefore, road density and traffic intensity in a region may have severe impact on regional as well as local connectivity. Amphibians may be able to detect and avoid unsuitable habitat. Individuals’ ability to avoid roads can reduce road mortality but at the same time road...

  2. Altered Brain Functional Connectivity in Small-Cell Lung Cancer Patients after Chemotherapy Treatment: A Resting-State fMRI Study

    Directory of Open Access Journals (Sweden)

    Konstantinos Bromis

    2017-01-01

    Full Text Available Previous studies in small-cell lung cancer (SCLC patients have mainly focused on exploring neurocognitive deficits associated with prophylactic cranial irradiation (PCI. Little is known about functional brain alterations that might occur due to chemotherapy treatment in this population before PCI is administered. For this reason, we used resting-state functional Magnetic Resonance Imaging (fMRI to examine potential functional connectivity disruptions in brain networks, including the Default Mode Network (DMN, the Sensorimotor Network, and the Task-Positive Network (TPN. Nineteen SCLC patients after platinum-based chemotherapy treatment and thirteen controls were recruited in the current study. ROI-to-ROI and Seed-to-Voxel analyses were carried out and revealed functional connectivity deficits in patients within all the networks investigated demonstrating the possible negative effect of chemotherapy in cognitive functions in SCLC populations.

  3. Understanding and Connections between Equations and Graphs.

    Science.gov (United States)

    Knuth, Eric J.

    2000-01-01

    Presents results from a study that examined students' understanding of connections between algebraic and graphical representations of functions. Discusses a possible reason for the inadequate and often absent connections that students made between them. (ASK)

  4. In vitro study of the efficacy of a two-way connection with disinfectant in the prevention of peritonitis.

    Science.gov (United States)

    Buoncristiani, U; Bianchi, P; Nasimi, M; Parlani, F; Covarelli, C; Buoncristiani, E; Bastianini, L; Bistoni, F

    2000-01-01

    A new connection system for continuous ambulatory peritoneal dialysis (CAPD) has been established, and its efficacy in preventing microbial contamination of the peritoneal cavity has been tested in vitro. The system consists of a Y-shaped channel formed in the bottom of a Plexiglas cup. The Luer-lock shaped ends of the Y-shaped channel are designed to host the connectors from the drainage bag, the catheter transfer set, and the bag of fresh dialysate. Because the connectors from the catheter transfer set and the fresh bag are located at the inner surface of the cup bed, and because the cup is filled with disinfectant during the entire exchange procedure, all at-risk steps are continuously protected by disinfectant (that is, removal of the caps from the connectors, connection and disconnection, replacement of the caps). Still, because the patient could inadvertently extract and contaminate one of the two connectors (although such a possibility is unlikely), the disinfecting efficacy of the system was tested in vitro. Despite contamination with various micro-organisms at the highest possible concentrations, all tests showed negative bacterial growth, thus confirming the absolute efficacy of the system in preventing exogenous transluminal peritonitis.

  5. TMS and TMS-EEG techniques in the study of the excitability, connectivity, and plasticity of the human motor cortex.

    Science.gov (United States)

    Ferreri, Florinda; Rossini, Paolo Maria

    2013-01-01

    Increasing evidence supports the notion that brain plasticity involves distinct functional and structural components, each entailing a number of cellular mechanisms operating at different time scales, synaptic loci, and developmental phases within an extremely complex framework. However, the exact relationship between functional and structural components of brain plasticity/connectivity phenomena is still unclear and its explanation is a major challenge within modern neuroscience. Transcranial magnetic stimulation (TMS), with or without electroencephalography (EEG), is a sensitive and objective measure of the effect of different kinds of noninvasive manipulation of the brain's activity, particularly of the motor cortex. Moreover, the key feature of TMS and TMS-EEG coregistration is their crucial role in tracking temporal dynamics and inner hierarchies of brain functional and effective connectivities, possibly clarifying some essential issues underlying brain plasticity. All together, the findings presented here are significant for the adoption of the TMS and TMS-EEG coregistration techniques as a tool for basic neurophysiologic research and, in the future, even for clinical diagnostics purposes.

  6. Use of cepstral analyses for differentiating normal from dysphonic voices: a comparative study of connected speech versus sustained vowel in European Portuguese female speakers.

    Science.gov (United States)

    Brinca, Lilia F; Batista, Ana Paula F; Tavares, Ana Inês; Gonçalves, Ilídio C; Moreno, Maria L

    2014-05-01

    The aim of this study was to investigate the use of cepstral peak prominence (CPP) and CPP-smoothed (CPPs) to differentiate dysphonic from nondysphonic voices, using two speech tasks: sustained vowel /a/ and connected speech. A retrospective study was based on data selected from an archival database of recorded voices. Sixty age- and occupation-matched individuals (30 participants with dysphonia and 30 controls) were recorded producing the sustained vowel /a/ and reading the European Portuguese version of "The Story of Arthur the Rat." Recorded voices were analyzed acoustically by measuring CPP and CPPs and auditory-perceptual ratings were related to the acoustic measurements. For the sustained vowel, both CPP and CPPs measures were significantly different between dysphonic and control groups. For connected speech, only CPP values revealed significant differences between the two groups, both in direct and narrative speech. Acoustic measurements correlated with the auditory-perceptual classifications in both sustained vowel and connected speech, although the strongest correlation (0.6 < r < 0.7) was obtained between CPP and the perception of breathiness. The results of this study suggest that analysis of CPP and CPPs is a promising tool in clinical practice with European Portuguese speakers. Copyright © 2014 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  7. Mapping inter-regional connectivity of the entire cortex to characterize major depressive disorder: a whole-brain diffusion tensor imaging tractography study.

    Science.gov (United States)

    Korgaonkar, Mayuresh S; Cooper, Nicholas J; Williams, Leanne M; Grieve, Stuart M

    2012-06-20

    Diffusion tensor imaging (DTI) can be used to study the organization of brain white matter noninvasively. The aim of this study was to present a proof of concept for integrating DTI with high-resolution anatomical (T1) images to map and assess inter-regional connectivity across the entire cortex in a cohort of healthy participants and compared with patients with major depressive disorder. We used MRI data of 23 patients and 23 matched controls, assessed as part of baseline testing in the International Study to Predict Optimized Treatment in Depression (iSPOT-D). Freesurfer was used to analyze the T1 images to automatically label 35 gyral-based areas for each hemisphere. DTI tractography was performed to parcellate intercortical tracts using each of these areas in seed-target combinations. We quantified fractional anisotropy, number-of-fiber connections, and fiber path length for each DTI connection, with the goal of identifying the best measure or combination of measures to characterize major depression. The best classification accuracy for the individual measures was achieved using the number-of-fibers data, whereas the combination model provided a slight improvement. The most discriminant features between the two groups were for white matter associated with the limbic, frontal, and thalamic projection fibers and as part of cortical connections between the left inferior temporal and the postcentral cortex; the left parstriangularis and the left superior frontal; the left cuneus and the corpus callosum; the left lingual and the right lateral occipital, the right superior parietal and the right superior temporal cortices; and the right inferior parietal and the right insula and postcentral cortices.

  8. Altered structural and functional connectivity between the bilateral primary motor cortex in unilateral subcortical stroke: A multimodal magnetic resonance imaging study.

    Science.gov (United States)

    Zhang, Yong; Li, Kuang-Shi; Ning, Yan-Zhe; Fu, Cai-Hong; Liu, Hong-Wei; Han, Xiao; Cui, Fang-Yuan; Ren, Yi; Zou, Yi-Huai

    2016-08-01

    A large number of functional imaging studies have focused on the understanding of motor-related neural activities after ischemic stroke. However, the knowledge is still limited in the structural and functional changes of the interhemispheric connections of the bilateral primary motor cortices (M1s) and their potential influence on motor function recovery following stroke.Twenty-four stroke patients with right hemispheric subcortical infarcts and 25 control subjects were recruited to undergo multimodal magnetic resonance imaging examinations. Structural impairments between the bilateral M1s were measured by fractional anisotropy. Functional changes of the bilateral M1s were assessed via M1-M1 resting-state functional connectivity. Task-evoked activation analysis was applied to identify the roles of the bilateral hemispheres in motor function recovery. Compared with control subjects, unilateral subcortical stroke patients revealed significantly decreased fractional anisotropy and functional connectivity between the bilateral M1s. Stroke patients also revealed higher activations in multiple brain regions in both hemispheres and that more regions were located in the contralesional hemisphere.This study increased our understanding of the structural and functional alterations between the bilateral M1s that occur in unilateral subcortical stroke and provided further evidence for the compensatory role played by the contralesional hemisphere for these alterations during motor function recovery.

  9. Hard X-ray Spectroscopic, Microwave and H-alpha Linear Polarization Studies with Hard X-Ray Observations from HESSI

    Science.gov (United States)

    Kiplinger, Alan L.

    2005-01-01

    The Principal Investigator (P.I.) has been pursuing a three year grant under NASA's Sun-Earth Connection Guest Investigator Program in support of the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). An objective of these efforts is to combine X-ray and other data on solar flares, coronal mass ejections and interplanetary particle events in order to obtain a more comprehensive recognition of signatures, and understanding of interplanetary proton events. Thus, part of these efforts are to investigate if signatures seen in hard X-rays and microwaves can lead to better predictions of interplanetary proton events that can be dangerous to astronauts and spacecraft. The original proposal was written in May, 2000 and it discusses a three-pronged approach for data comparisons with three new types of instrumentation observing at X-ray, microwave and optical wavelengths. The major impetus behind this work and the proposal is that the P.I. discovered a strong correlation between a particular type of hard X-ray signature seen in spectral evolutions and interplanetary proton events (Kiplinger, 1995). The basic signature is that hard X-ray flux peaks either exhibit spectra that soften on their decays (Le. show fewer and fewer high energy X-rays with time) or they harden during decays (i.e. high energy X-rays decay significantly slower that lower energy X-rays). This signature is called progressive hardening. Studies were conducted over an eight-year period of data from the Hard X-Ray Burst Spectrometer (HXRBS) of the Solar maximum mission. Out of the 750 well observed flares studied, 41 flares had major associated proton events. Of these, 29 events were predicted on the basis of progressive hardening for a hit rate of 71%. The 152 largest flares had a hit rate of 82%.

  10. Spectral power and functional connectivity changes during mindfulness meditation with eyes open: A magnetoencephalography (MEG) study in long-term meditators.

    Science.gov (United States)

    Wong, W P; Camfield, D A; Woods, W; Sarris, J; Pipingas, A

    2015-10-01

    Whilst a number of previous studies have been conducted in order to investigate functional brain changes associated with eyes-closed meditation techniques, there is a relative scarcity in the literature with regards to changes occurring during eyes-open meditation. The current project used magnetoencephalography (MEG) to investigate differences in spectral power and functional connectivity between 11 long-term mindfulness meditators (LTMMs) with >5 years of experience and 12 meditation-naïve control participants both during baseline eyes-open rest and eyes-open open-monitoring (OM) mindfulness meditation. During resting with eyes-open, prior to meditating, greater mean alpha power was observed for LTMMs in comparison to controls. However, during the course of OM meditation, a significantly greater increase in theta power was observed over a broad fronto-centro-parietal region for control participants in comparison to LTMMs. In contrast, whole-head mean connectivity was found to be significantly greater for long-term meditators in comparison to controls in the theta band both during rest as well as during meditation. Additionally, mean connectivity was significantly lower for long-term meditators in the low gamma band during rest and significantly lower in both low and high gamma bands during meditation; and the variance of low-gamma connectivity scores for long-term meditators was significantly decreased compared to the control group. The current study provides important new information as to the trait functional changes in brain activity associated with long-term mindfulness meditation, as well as the state changes specifically associated with eyes-open open monitoring meditation techniques.

  11. A study on the connection and physical properties of Cadmium selenide nanoparticles and zinc sulfide nanoparticles made by ultrasonic method

    Directory of Open Access Journals (Sweden)

    Shabnam Taheriniya

    2016-04-01

    Full Text Available Ultrasonic waves are called to hordes of mechanical waves that their oscillation frequency exceeds from human hearing range (20 Hz- 20 KHz. These waves have various applications due to their properties; ultrasonic frequency acoustic waves (16 KHz to 2 MHz are used for curing and ultrasonic process parameters (amplitude, frequency and power can be controlled properly. Ultrasonic process in fluids is followed by acoustic cavitation phenomenon (cavitation. Indeed, acoustic cavitation refers to the formation of bubbles (pores due to the rapid drop in water caused by passing the sound waves through it. In this research, an action was made to produce CdSe and ZnS nanoparticles using this method. Ultimately, ZnS quantum dots and ZnS nanoparticles were connected to each other using a coupling agent copolymer (PEG-PCA. The optical properties of this nanoparticle were examined by using X-ray diffraction and evaluated using UV-Visblel range of coupling effect.

  12. Task-specific modulation of effective connectivity during two simple unimanual motor tasks: A 122-channel EEG study

    DEFF Research Database (Denmark)

    Herz, Damian M.; Christensen, Mark S.; Reck, Christiane

    2012-01-01

    -related modulations of inter-regional coupling within a core motor network comprising the left primary motor cortex (M1), lateral premotor cortex (lPM) and supplementary motor area (SMA) were then modeled using dynamic causal modeling (DCM). A network model postulating coupling both within and across frequencies best...... captured observed spectral responses according to Bayesian model selection. DCM revealed dominant coupling within the β-band (13–30 Hz) between M1 and SMA during isometric contraction of the forearm, whereas fast repetitive finger movements were characterized by strong coupling within the γ-band (31–48 Hz......) and between the θ- (4–7 Hz) and the γ-band. This coupling pattern was mainly expressed in connections from lPM to SMA and from lPM to M1. We infer that human manual motor control involves task-specific modulation of inter-regional oscillatory coupling both within and across distinct frequency bands...

  13. [Preliminary study of the expression of connective tissue growth factor in papillary muscles of the patients with rheumatic heart disease].

    Science.gov (United States)

    Wang, Y N; Li, T; Gu, J R; Yu, B Y

    2016-04-19

    To investigate the expression and the effect of connective tissue growth factor (CTGF) on rheumatic myocardial fibrosis of rheumatic heart disease (RHD). The papillary muscles samples were obtained from patients with RHD during mitral valve replacement.The expression of TGF-β1, CTGF mRNA and CTGF protein were detected with semiquantitative RT-PCR technique and immunohistochemistry technologyin the papillary muscles cell from 41RHD patients and 20 normal papillary muscles samples.The area of myocardial fibrosis was measured by imaging analysis system. SPSS package was used to analyze the relationship between the expression of CTGF and the area of myocardial fibrosis. Compared with normal controls (PU 2.4±0.9), the mean level of CTGF protein expression in the papillary muscles samples of the RHD patients (PU 44.7±6.0) was significantly increased(Pfibrosis (r=0.856, Pfibrosis of RHD.

  14. Framework for Connections on Facebook

    DEFF Research Database (Denmark)

    Sudzina, Frantisek

    There is a substantial amount of current information systems and marketing research focused on social networking sites, most frequently on Facebook. Often, these studies utilize available metadata on user on-line behavior, such as what links the users clicked on. In order to better understand...... behavior of Facebook users, it makes sense to investigate also whom the users connect to. It is possible to hypothesize that behavior of people, who connect only to relatives on Facebook, differs from behavior of people, who are connected only to their classmates. The paper offers a framework of Facebook...

  15. Earthquake activity in Sweden. Study in connection with a proposed nuclear waste repository in Forsmark or Oskarshamn

    Energy Technology Data Exchange (ETDEWEB)

    Boedvarsson, Reynir; Lund, Bjoern; Roberts, Roland; Slunga, Ragnar [Uppsala Univ. (Sweden). Dept. of Earth Sciences

    2006-02-15

    The aim of this report is to evaluate the risks for future earthquakes in the vicinity of the proposed nuclear waste repository sites at Forsmark and Oskarshamn. Time periods of 100 and 1,000 years will be considered, which implies that the focus of this study is on an evaluation of the current, general situation in the region. Major events on a longer time scale, such as an ice-age, will only be briefly considered. Earthquakes are products of ongoing deformations within the Earth and this report will, therefore, concentrate on the current state of knowledge about deformations in the region. As earthquakes are our most important source of information about deformations at depth in the crust, we will focus on the available seismic data using the Nordic earthquake catalog maintained at the Institute of Seismology, Helsinki University, and the recent data from the new Swedish National Seismic Network. Direct measurements of surface deformation using the Global Positioning System will also be utilized in the analysis. Sweden is a low seismicity area, with most earthquakes being observed in the south-west, around Lake Vaenern, along the north-east coast and in Norrbotten. South-eastern Sweden is on the contrary relatively inactive. Seismicity is also, generally, episodic in time which together with the short period of instrumental observation, approximately 100 years, makes our knowledge about the activity far from complete. Although very large earthquakes (magnitude about 8) have occurred in Sweden, it is generally agreed that these were connected to the late stages of deglaciation at the end of the previous ice-age. At the time scales considered in this report, inferences from current seismicity is of more relevance. This data suggests that we should expect at least one magnitude 5 earthquake in our region every century and one magnitude 6 earthquake every one thousand years. In order to illustrate the effects of static and dynamic deformation from a magnitude 5

  16. Earthquake activity in Sweden. Study in connection with a proposed nuclear waste repository in Forsmark or Oskarshamn

    Energy Technology Data Exchange (ETDEWEB)

    Boedvarsson, Reynir; Lund, Bjoern; Roberts, Roland; Slunga, Ragnar [Uppsala Univ. (Sweden). Dept. of Earth Sciences

    2006-02-15

    The aim of this report is to evaluate the risks for future earthquakes in the vicinity of the proposed nuclear waste repository sites at Forsmark and Oskarshamn. Time periods of 100 and 1,000 years will be considered, which implies that the focus of this study is on an evaluation of the current, general situation in the region. Major events on a longer time scale, such as an ice-age, will only be briefly considered. Earthquakes are products of ongoing deformations within the Earth and this report will, therefore, concentrate on the current state of knowledge about deformations in the region. As earthquakes are our most important source of information about deformations at depth in the crust, we will focus on the available seismic data using the Nordic earthquake catalog maintained at the Institute of Seismology, Helsinki University, and the recent data from the new Swedish National Seismic Network. Direct measurements of surface deformation using the Global Positioning System will also be utilized in the analysis. Sweden is a low seismicity area, with most earthquakes being observed in the south-west, around Lake Vaenern, along the north-east coast and in Norrbotten. South-eastern Sweden is on the contrary relatively inactive. Seismicity is also, generally, episodic in time which together with the short period of instrumental observation, approximately 100 years, makes our knowledge about the activity far from complete. Although very large earthquakes (magnitude about 8) have occurred in Sweden, it is generally agreed that these were connected to the late stages of deglaciation at the end of the previous ice-age. At the time scales considered in this report, inferences from current seismicity is of more relevance. This data suggests that we should expect at least one magnitude 5 earthquake in our region every century and one magnitude 6 earthquake every one thousand years. In order to illustrate the effects of static and dynamic deformation from a magnitude 5

  17. Abnormalities of inter- and intrahemispheric functional connectivity in Autism Spectrum Disorders: A study using the Autism Brain Imaging Data Exchange database

    Directory of Open Access Journals (Sweden)

    Jung Min eLee

    2016-05-01

    Full Text Available Recently, the Autism Brain Imaging Data Exchange (ABIDE project revealed decreased functional connectivity in individuals with Autism Spectrum Disorders (ASD relative to the typically developing controls (TDCs. However, it is still questionable whether the source of functional underconnectivity in subjects with ASD is equally contributed by the ipsilateral and contralateral parts of the brain. In this study, we decomposed the inter- and intrahemispheric regions and compared the functional connectivity density (FCD between 458 subjects with ASD and 517 TDCs from the ABIDE database. We quantified the inter- and intrahemispheric FCDs in the brain by counting the number of functional connectivity with all voxels in the opposite and same hemispheric brain regions, respectively. Relative to TDCs, both inter- and intrahemispheric FCDs in the posterior cingulate cortex, lingual/parahippocampal gyrus, and postcentral gyrus were significantly decreased in subjects with ASD. Moreover, in the ASD group, the restricted and repetitive behavior subscore of the Autism Diagnostic Observation Schedule (ADOS-RRB score showed significant negative correlations with the average interhemispheric FCD and contralateral FCD in the lingual/parahippocampal gyrus cluster. Also, the ADOS-RRB score showed significant negative correlations with the average contralateral FCD in the default mode network regions such as the posterior cingulate cortex and precuneus. Taken together, our findings imply that a deficit of non-social functioning processing in ASD such as restricted and repetitive behaviors and sensory hypersensitivity could be determined via both inter- and intrahemispheric functional disconnections.

  18. Serum BDNF correlates with connectivity in the (pre)motor hub in the aging human brain--a resting-state fMRI pilot study.

    Science.gov (United States)

    Mueller, Karsten; Arelin, Katrin; Möller, Harald E; Sacher, Julia; Kratzsch, Jürgen; Luck, Tobias; Riedel-Heller, Steffi; Villringer, Arno; Schroeter, Matthias L

    2016-02-01

    Brain-derived neurotrophic factor (BDNF) has been discussed to be involved in plasticity processes in the human brain, in particular during aging. Recently, aging and its (neurodegenerative) diseases have increasingly been conceptualized as disconnection syndromes. Here, connectivity changes in neural networks (the connectome) are suggested to be the most relevant and characteristic features for such processes or diseases. To further elucidate the impact of aging on neural networks, we investigated the interaction between plasticity processes, brain connectivity, and healthy aging by measuring levels of serum BDNF and resting-state fMRI data in 25 young (mean age 24.8 ± 2.7 (SD) years) and 23 old healthy participants (mean age, 68.6 ± 4.1 years). To identify neural hubs most essentially related to serum BDNF, we applied graph theory approaches, namely the new data-driven and parameter-free approach eigenvector centrality (EC) mapping. The analysis revealed a positive correlation between serum BDNF and EC in the premotor and motor cortex in older participants in contrast to young volunteers, where we did not detect any association. This positive relationship between serum BDNF and EC appears to be specific for older adults. Our results might indicate that the amount of physical activity and learning capacities, leading to higher BDNF levels, increases brain connectivity in (pre)motor areas in healthy aging in agreement with rodent animal studies. Pilot results have to be replicated in a larger sample including behavioral data to disentangle the cause for the relationship between BDNF levels and connectivity. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Study of electrical and thermal characteristics of inverters for grid-connected photovoltaic systems; Estudo de caracteristicas eletricas e termicas de inversores para sistemas fotovoltaicos conectados a rede

    Energy Technology Data Exchange (ETDEWEB)

    Rampinelli, Giuliano Arns

    2010-12-15

    Grid-connected photovoltaic systems directly convert solar energy into electrical energy delivering to the distribution grid a clean and renewable energy. These systems are basically formed by an array of photovoltaic modules and inverters. The inverters are responsible for converting direct current to alternating current. A study of electrical and thermal characteristics of inverters used in grid-connected photovoltaic systems from a theoretical and experimental analysis. The inverters tests were carried out in two stages: the first stage was performed at Solar Energy Lab. of the Federal University of Rio Grande do Sul (UFRGS), Brazil, where it was used a 4,8 kW{sub p} grid-connected photovoltaic system and ten inverters of different manufacturers. The inverters electrical characteristics measured and analyzed were: direct current to alternating current conversion efficiency, maximum power point tracker efficiency, power factor and harmonic distortion in current and voltage. Inverters thermal testing was also conducted and its results are presented ana analyzed. The second stage of the experimental tests was performed at Photovoltaic Solar Energy Lab. at CIEMAT in Spain. It was used 3 kW{sub p} photovoltaic system and seven inverters of different manufacturers. The inverters are single-phase, up to 5 kW and different topologies (high frequency transformer, low frequency transformer and transformerless). The influence of DC voltage input in the behavior of DC to AC conversion efficiency and power factor was analyzed. The results of the tests allowed the development of mathematical models that describe the electrical and thermal behavior of the inverters. The proposed mathematical models were inserted into computer simulation software developed at UFRGS named FVConect. The evolution of the simulation results compared to the experimental results validates the proposed models. The analysis of the behavior of the inverters improves the understanding of the operating os

  20. Strengthening connections: functional connectivity and brain plasticity.

    Science.gov (United States)

    Kelly, Clare; Castellanos, F Xavier

    2014-03-01

    The ascendancy of functional neuroimaging has facilitated the addition of network-based approaches to the neuropsychologist's toolbox for evaluating the sequelae of brain insult. In particular, intrinsic functional connectivity (iFC) mapping of resting state fMRI (R-fMRI) data constitutes an ideal approach to measuring macro-scale networks in the human brain. Beyond the value of iFC mapping for charting how the functional topography of the brain is altered by insult and injury, iFC analyses can provide insights into experience-dependent plasticity at the macro level of large-scale functional networks. Such insights are foundational to the design of training and remediation interventions that will best facilitate recovery of function. In this review, we consider what is currently known about the origin and function of iFC in the brain, and how this knowledge is informative in neuropsychological settings. We then summarize studies that have examined experience-driven plasticity of iFC in healthy control participants, and frame these findings in terms of a schema that may aid in the interpretation of results and the generation of hypotheses for rehabilitative studies. Finally, we outline some caveats to the R-fMRI approach, as well as some current developments that are likely to bolster the utility of the iFC paradigm for neuropsychology.

  1. Study of imbalanced internal resistance on drop voltage of LiFePO4 battery system connected in parallel

    Science.gov (United States)

    Adie Perdana, Fengky; Supriyanto, Agus; Purwanto, Agus; Jamaluddin, Anif

    2017-01-01

    The purpose of this research focuses on the effect of imbalanced internal resistance for the drop voltage of LiFePO4 18650 battery system connected in parallel. The battery pack has been assembled consist of two cell battery LiFePO4 18650 that has difference combination of internal resistance. Battery pack was tested with 1/C constant current charging, 3,65V per group sel, 3,65V constant voltage charging, 5 minutes of rest time between charge and discharge process, 1/2C Constant current discharge until 2,2V, 26 cycle of measurement test, and 4320 minutes rest time after the last charge cycle. We can conclude that the difference combination of internal resistance on the battery pack seriously influence the drop voltage of a battery. Theoretical and experimental result show that the imbalance of internal resistance during cycling are mainly responsible for the drop voltage of LiFePO4 parallel batteries. It is thus a good way to avoid drop voltage fade of parallel battery system by suppressing variations of internal resistance.

  2. Graph theoretical connectivity analysis of the human brain while listening to music with emotional attachment: feasibility study.

    Science.gov (United States)

    Karmonik, Christof; Brandt, Anthony K; Fung, Steve H; Grossman, Robert G; Frazier, J Todd

    2013-01-01

    Benefits of listening to music with emotional attachment while recovering from a cerebral ischemic event have been reported. To develop a better understanding of the effects of music listening on the human brain, an algorithm for the graph-theoretical analysis of functional magnetic resonance imaging (fMRI) data was developed. From BOLD data of two paradigms (block-design, first piece: music without emotional attachment, additional visual guidance by a moving cursor in the score sheet; second piece: music with emotional attachment), network graphs were constructed with correlations between signal time courses as edge weights. Functional subunits in these graphs were identified with the MCODE clustering algorithm and mapped back into anatomical space using AFNI. Emotional centers including the right amygdala and bilateral insula were activated by the second piece (emotional attachment) but not by the first piece. Network clustering analysis revealed two separate networks of small-world property corresponding to task-oriented and resting state conditions, respectively. Functional subunits with highest interactions were bilateral precuneus for the first piece and left middle frontal gyrus and right amygdala, bilateral insula, left middle temporal gyrus for the second piece. Our results indicate that fMRI in connection with graph theoretical network analysis is capable of identifying and differentiating functional subunits in the human brain when listening to music with and without emotional attachment.

  3. Change of Neural Connectivity of the Red Nucleus in Patients with Striatocapsular Hemorrhage: A Diffusion Tensor Tractography Study

    Directory of Open Access Journals (Sweden)

    Sung Ho Jang

    2015-01-01

    Full Text Available The red nucleus (RN is involved in motor control and it is known to have potential to compensate for injury of the corticospinal tract (CST. We investigated the change of connectivity of the RN (RNc and its relation to motor function in patients with striatocapsular hemorrhage. Thirty-five chronic patients with striatocapsular hemorrhage were recruited. Motricity Index (MI, Modified Brunnstrom Classification (MBC, and Functional Ambulation Category (FAC were measured for motor function. The probabilistic tractography method was used for evaluation of the RNc. Fractional anisotropy (FA, mean diffusivity (MD, and tract volume (TV of the RNc were measured. FA and TV ratios of the RNc in patients with discontinuation of the affected CST were significantly higher than those of patients with preserved integrity of the CST in the affected hemisphere (p<0.05. TV ratio of the RNc showed significant negative correlation with upper MI (weak correlation, r=-0.35, total MI (weak correlation, r=-0.34, and MBC (moderate correlation, r=-0.43, respectively (p<0.05. We found that the neural structure of the RNc was relatively increased in the unaffected hemisphere compared with the affected hemisphere in patients with more severe injury of the CST.

  4. Relationship between epithelial and connective tissues in the stomach of the frog Rana temporaria during metamorphosis: an ultrastructural study.

    Science.gov (United States)

    Villaro, A C; Rovira, J; Bodegas, M E; Burrell, M A; Sesma, P

    1998-08-01

    In the course of metamorphosis of the stomach of Rana temporaria tadpoles there is a marked increase in the amount of active mesenchymal fibroblasts and extracellular matrix underlying the regenerating gastric epithelium. At the onset of metamorphosis, a thick PAS-positive basement membrane is developed around the epithelial component of the mucosa, formed by the apical, degenerating larval epithelium and the basal, regenerative epithelial cords. Under the electron microscope, a folded basement membrane is usually revealed under the apical degenerating epithelium while a compact basement membrane (up to 1-2 microns thick), forming both patches and more extensive areas, is frequently seen around the regenerative glandular cords. Cytoplasmic processes, extending from both the epithelial and mesenchymal fibroblastic cells, cross the basement membrane and make physical contact between the two cellular types. At mid-metamorphosis areas of thick PAS-positive basement membrane are still observed around the differentiating glandular outlines, before disappearing completely at late metamorphosis. The probable involvement of intertissue interactions between epithelium and connective elements in the morphogenesis, proliferation and differentiation of secondary, definitive frog stomach is discussed. Early contacts between epithelium and phagocytes, probably related to the invasion of epithelium by the phagocytic cells, have also been observed.

  5. How Extended Is Wernicke’s Area? Meta-Analytic Connectivity Study of BA20 and Integrative Proposal

    Directory of Open Access Journals (Sweden)

    Alfredo Ardila

    2016-01-01

    Full Text Available Understanding the functions of different brain areas has represented a major endeavor of contemporary neurosciences. The purpose of this paper was to pinpoint the connectivity of Brodmann area 20 (BA20 (inferior temporal gyrus, fusiform gyrus in language tasks. A meta-analysis was conducted to assess the language network in which BA20 is involved. The DataBase of Brainmap was used; 11 papers corresponding to 12 experimental conditions with a total of 207 subjects were included in this analysis. Our results demonstrated seven clusters of activation including other temporal lobe areas (BA3, BA21, the insula, and the prefrontal cortex; minor clusters in the cingulate gyrus and the occipital lobe were observed; however, the volumes of all the activation clusters were small. Our results suggest that regardless of BA20 having certain participation in language processes it cannot be considered as a core language processing area (Wernicke’s area; nonetheless, it could be regarded as kind of language processing marginal area, participating in “extended Wernicke’s area” or simply “Wernicke’s system.” It is suggested that “core Wernicke’s area” roughly corresponds to BA21, BA22, BA41, and BA42, while a “language associations area” roughly corresponds to BA20, BA37, BA38, BA39, and BA40 (“extended Wernicke’s area” or “Wernicke’s system”.

  6. Connections of the torus semicircularis and oliva superior in the frog, Rana esculenta: a Phaseolus vulgaris leucoagglutinin labeling study.

    Science.gov (United States)

    Matesz, C; Kulik, A

    1996-01-01

    The afferent and efferent connections of the frog principal nucleus (TP) of torus semicircularis (TOS) and superior olive (SO) were examined by employing the anterograde and retrograde transport patterns of Phaseolus vulgaris leucoagglutinin (PHA-L). After injecting the tracer into these nuclei it was found that the TP projected to the ipsilateral posterior and central thalamic nuclei, all subdivisions of the bilateral TDS and the ipsilateral nucleus isthmi (NI). In the rhombencephalon the projection was restricted mainly to the contralateral SO and the cochlear nucleus (CN). Retrogradely labeled cells were found in most of the areas that contained anterogradely labeled terminals. The termination areas of the SO fibers were similar to the projections of fibers of TP origin in the diencephalic and in the mesencephalic auditory centers. A strong projection was followed into the contralateral SO; the CNs received fibers at both sides. Caudally to the SO the reticular formation, the spinal nucleus of the trigeminal nerve, the solitary nucleus and the dorsal column nuclei were supplied by the fibers of the SO origin. Retrogradely labeled cells were found in the TOS, tegmental nuclei, solitary nucleus, dorsal column nuclei and in the spinal nucleus of the trigeminal nerve. Our results indicate that the frog auditory pathway is more complex at the level of the secondary and tertiary fiber projections than has been previously recognized.

  7. Wetland Hydrological Connectivity: A Classification Approach and Continental Assessment

    Science.gov (United States)

    Connectivity has become a major focus of hydrological and ecological studies. Connectivity influences fluxes between landscape elements, while isolation reduces flows between elements. Thus connectivity can be an important characteristic controlling ecosystem services. Hydrolo...

  8. Connectivity threshold for Bluetooth graphs

    CERN Document Server

    Broutin, Nicolas; Fraiman, Nicolas; Lugosi, Gábor

    2011-01-01

    We study the connectivity properties of random Bluetooth graphs that model certain "ad hoc" wireless networks. The graphs are obtained as "irrigation subgraphs" of the well-known random geometric graph model. There are two parameters that control the model: the radius $r$ that determines the "visible neighbors" of each node and the number of edges $c$ that each node is allowed to send to these. The randomness comes from the underlying distribution of data points in space and from the choices of each vertex. We prove that no connectivity can take place with high probability for a range of parameters $r, c$ and completely characterize the connectivity threshold (in $c$) for values of $r$ close the critical value for connectivity in the underlying random geometric graph.

  9. A knowledge discovery approach to explore some Sun/Earth's climate relationships

    Science.gov (United States)

    Pou, A.; Valdes, J.

    2009-09-01

    Recent developments in data driven modeling and analysis including computational intelligence techniques may throw new light on the exploration of possible solar activity/Earth's climate relationships. Here we present three different examples of methodologies under development and some preliminary results. a) Multivariate Time Series Model Mining (MVTSMM) analysis [1] and Genetic Programming were applied to Greenland's CRETE Site-E ice core Delta O18/16 values (1721-1983, one year interval sampling) and with sunspots activity (International Sunspots Number) during the same time span [2]. According to the results (1771 to 1933 period) indicated by the lag importance spectrum obtained with MVTSMM analysis, the sun's activity itself shows high internal variability and is inhomogeneous. The Dalton minimum, a low activity period usually considered to occur between 1790 and 1830, is shown to be a complex structure beginning about 1778 and ending in 1840. Apparently, the system entered a new state in 1912. In the joint analysis, the analytical tool uses extensively the solar activity data to explain the Delta O18/16 data, showing areas of stable patterns, lag drifts and abrupt pattern disruptions, indicating changes of state in the solar processes of several kinds at different times. b) A similar MVTSMM analysis was conducted on Central England Temperature (CET) and solar activity data using Group Sunspots Number (GSN) with a useful interpretive span of time from 1771 to 1916. The joint analysis involved large amounts of solar activity variables, except for the 1843-1862 and 1877-1889 periods where the discovered models used much less information from GSN data. As with the Crete-E/ISN analysis the lag importance spectrum of CET/GSN shows a number of clear discontinuities. A quarter of them are present in both (1778-1779, 1806, 1860-1862, 1912-1913). These experiments were designed for testing methodologies and not for specific hypothesis testing. However, it seems that Delta O18/16 data would more readily respond to solar influences. This raises the suspicion that perhaps they do not only reflect temperatures but also solar activity, as well as other possible factors not directly related to atmospheric temperatures. These methodologies may be useful as exploratory tools, directing the attention to specific areas where further research should be required. This could be the case of the Delta O18/16 data, frequently considered to be a reliable and accurate proxy of temperatures. c) Another experiment was made using daily maximum temperatures from 10 Spanish meteorological stations for the period 1901-2005 [3]. Using a hybrid procedure (Differential Evolution and Fletcher-Reeves Classical Optimization) it was found that a subset was capable of preserving the 10-dimensional similarity when nonlinearly mapped into 1D. A daily index, F1 was applied to the whole dataset and grouped by years and transformed into a Kolmogorov-Smirnov dissimilarity matrix, space optimized and clustered giving the following landmarks: 1911-12, 1919-1920, 1960, 1973 and 1989. A visual comparison with the aa geomagnetic index may suggest a certain coupling with changes in the magnetic field behavior. The complexity of the patterns suggest that the possible relationships between Earth's climate and solar activity may occur in much more complex ways than just irradiance variations and simple linear correlations. REFERENCES: [1] Valdés, J.J., Bonham-Carter, G. " Time Dependent Neural Network Models For Detecting Changes of State in Complex Processes: Applications in Earth Sciences and Astronomy”. Neural Networks, vol 19, (2), pp 196-207, 2006. [2] Valdés, J., Pou, A. "Greenland Temperatures and Solar Activity: A Computational Intelligence Approach," Proceedings of the 2007 IEEE International Joint Conference on Neural Networks (IJCNN 2007). Orlando, Florida, USA. August 12-17, 2007. [3] Valdés, J., Pou, A., Orchard, B. "Characterization of Climatic Variations in Spain at the Regional Scale: A Computational Intelligence Approach," Proceedings of the IEEE World Congress on Computational Intelligence (WCCI-2008). Hong Kong, China. June 1, 2008.

  10. Sun, the Earth, and Near-Earth Space: A Guide to the Sun-Earth System

    Science.gov (United States)

    Eddy, John A.

    2010-01-01

    In a world of warmth and light and living things we soon forget that we are surrounded by a vast universe that is cold and dark and deadly dangerous, just beyond our door. On a starry night, when we look out into the darkness that lies around us, the view can be misleading in yet another way: for the brightness and sheer number of stars, and their chance groupings into familiar constellations, make them seem much nearer to each other, and to us, that in truth they are. And every one of them--each twinkling, like a diamond in the sky--is a white-hot sun, much like our own. The nearest stars in our own galaxy--the Milky Way-- are more than a million times further away from us than our star, the Sun. We could make a telephone call to the Moon and expect to wait but a few seconds between pieces of a conversation, or but a few hours in calling any planet in our solar system.

  11. International Symposium on Recent Observations and Simulations of the Sun-Earth System

    Science.gov (United States)

    2007-01-10

    Dynamics and the Response of Geospace 14. Chertoprud V., Ioshpa B., Obridko V.: Fractal Properties of Magnetic Fields of Active and Quiet Solar...Andenes, Norway. The project is partly financed by the Bulgarian Ministry of Science and Education. OTHER RELATED TOPICS: POSTER... Fractal

  12. Behavior of concentrically loaded CFT braces connections

    Directory of Open Access Journals (Sweden)

    Maha M. Hassan

    2014-03-01

    Full Text Available Concrete filled tubes (CFTs composite columns have many economical and esthetic advantages, but the behavior of their connections is complicated. Through this study, it is aimed to investigate the performance and behavior of different connection configurations between concrete filled steel tube columns and bracing diagonals through an experimental program. The study included 12 connection subassemblies consisting of a fixed length steel tube and gusset plate connected to the tube end with different details tested under half cyclic loading. A notable effect was observed on the behavior of the connections due to its detailing changes with respect to capacity, failure mode, ductility, and stress distribution.

  13. Behavior of concentrically loaded CFT braces connections.

    Science.gov (United States)

    Hassan, Maha M; Ramadan, Hazem M; Abdel-Mooty, Mohammed N; Mourad, Sherif A

    2014-03-01

    Concrete filled tubes (CFTs) composite columns have many economical and esthetic advantages, but the behavior of their connections is complicated. Through this study, it is aimed to investigate the performance and behavior of different connection configurations between concrete filled steel tube columns and bracing diagonals through an experimental program. The study included 12 connection subassemblies consisting of a fixed length steel tube and gusset plate connected to the tube end with different details tested under half cyclic loading. A notable effect was observed on the behavior of the connections due to its detailing changes with respect to capacity, failure mode, ductility, and stress distribution.

  14. Association of serum KL-6 levels with interstitial lung disease in patients with connective tissue disease: a cross-sectional study.

    Science.gov (United States)

    Oguz, Ekin Oktay; Kucuksahin, Orhan; Turgay, Murat; Yildizgoren, Mustafa Turgut; Ates, Askin; Demir, Nalan; Kumbasar, Ozlem Ozdemir; Kinikli, Gulay; Duzgun, Nursen

    2016-03-01

    It was aimed to evaluate KL-6 glycoprotein levels to determine if it may be a diagnostic marker for the connective tissue diseases (CTDs) predicting CTD-related interstitial lung diseases (ILDs) (CTD-ILD) development and to examine if there was a difference between patients and healthy controls. The study included 113 patients with CTD (45 CTD without lung involvement, 68 CTD-ILD) and 45 healthy control subjects. KL-6 glycoprotein levels were analyzed with ELISA in patients and the control group. The relationship between KL-6 glycoprotein levels and CTD-ILD was assessed. In the comparison of all the groups in the study, significantly higher levels of KL-6 were determined in the CTD-ILD group than in either the CTD without pulmonary involvement group or the healthy control group (p connective tissue diseases in the diagnostic groups (systemic lupus erythematosus, Sjögren's syndrome, rheumatoid arthritis, mixed connective tissue disease, scleroderma, polymyositis/ dermatomyositis). In the healthy control group, there was a statistically significant difference between KL-6 levels in smokers and non-smokers. Smokers had significantly higher serum KL-6 levels compared with non-smokers (p < 0.05). There was no statistically significant difference between smoking status (pack-year) and serum KL-6 levels. There was no statistically significant correlation between serum KL-6 levels and time since diagnosis of CTD and CTD-ILD. The level of KL-6 as a predictive factor could be used to identify the clinical development of ILD before it is detected on imaging modality. Further prospective clinical studies are needed to define whether levels of KL-6 might have prognostic value or might predict progressive ILD.

  15. Neural substrates underlying balanced time perspective: A combined voxel-based morphometry and resting-state functional connectivity study.

    Science.gov (United States)

    Guo, Yiqun; Chen, Zhiyi; Feng, Tingyong

    2017-08-14

    Balanced time perspective (BTP), which is defined as a mental ability to switch flexibly among different time perspectives Zimbardo and Boyd (1999), has been suggested to be a central component of positive psychology Boniwell and Zimbardo (2004). BTP reflects individual's cognitive flexibility towards different time frames, which leads to many positive outcomes, including positive mood, subjective wellbeing, emotional intelligence, fluid intelligence, and executive control. However, the neural basis of BTP is still unclear. To address this question, we quantified individual's deviation from the BTP (DBTP), and investigated the neural substrates of DBTP using both voxel-based morphometry (VBM) and resting-state functional connectivity (RSFC) methods VBM analysis found that DBTP scores were positively correlated with gray matter volume (GMV) in the ventral precuneus. We further found that DBTP scores were negatively associated with RSFCs between the ventral precuneus seed region and medial prefrontal cortex (mPFC), bilateral temporoparietal junction (TPJ), parahippocampa gyrus (PHG), and middle frontal gyrus (MFG). These brain regions found in both VBM and RSFC analyses are commonly considered as core nodes of the default mode network (DMN) that is known to be involved in many functions, including episodic and autobiographical memory, self-related processing, theory of mind, and imagining the future. These functions of the DMN are also essential to individuals with BTP. Taken together, we provide the first evidence for the structural and functional neural basis of BTP, and highlight the crucial role of the DMN in cultivating an individual's BTP. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Asymptotically hyperbolic connections

    CERN Document Server

    Fine, Joel; Krasnov, Kirill; Scarinci, Carlos

    2015-01-01

    General Relativity in 4 dimensions can be equivalently described as a dynamical theory of SO(3)-connections rather than metrics. We introduce the notion of asymptotically hyperbolic connections, and work out an analog of the Fefferman-Graham expansion in the language of connections. As in the metric setup, one can solve the arising "evolution" equations order by order in the expansion in powers of the radial coordinate. The solution in the connection setting is arguably simpler, and very straightforward algebraic manipulations allow one to see how the obstruction appears at third order in the expansion. Another interesting feature of the connection formulation is that the "counter terms" required in the computation of the renormalised volume all combine into the Chern-Simons functional of the restriction of the connection to the boundary. As the Chern-Simons invariant is only defined modulo large gauge transformations, the requirement that the path integral over asymptotically hyperbolic connections is well-d...

  17. Structural and connectomic neuroimaging for the personalized study of longitudinal alterations in cortical shape, thickness and connectivity after traumatic brain injury.

    Science.gov (United States)

    Irimia, A; Goh, S Y; Torgerson, C M; Vespa, P; Van Horn, J D

    2014-09-01

    The integration of longitudinal brain structure analysis with neurointensive care strategies continues to be a substantial difficulty facing the traumatic brain injury (TBI) research community. For patient-tailored case analysis, it remains challenging to establish how lesion profile modulates longitudinal changes in cortical structure and connectivity, as well as how these changes lead to behavioral, cognitive and neural dysfunction. Additionally, despite the clinical potential of morphometric and connectomic studies, few analytic tools are available for their study in TBI. Here we review the state of the art in structural and connectomic neuroimaging for the study of TBI and illustrate a set of recently-developed, patient-tailored approaches for the study of TBI-related brain atrophy and alterations in morphometry as well as inter-regional connectivity. The ability of such techniques to quantify how injury modulates longitudinal changes in cortical shape, structure and circuitry is highlighted. Quantitative approaches such as these can be used to assess and monitor the clinical condition and evolution of TBI victims, and can have substantial translational impact, especially when used in conjunction with measures of neuropsychological function.

  18. STRUCTURAL AND CONNECTOMIC NEUROIMAGING FOR THE PERSONALIZED STUDY OF LONGITUDINAL ALTERATIONS IN CORTICAL SHAPE, THICKNESS AND CONNECTIVITY AFTER TRAUMATIC BRAIN INJURY

    Science.gov (United States)

    Irimia, A.; Goh, S.-Y. M.; Torgerson, C. M.; Vespa, P. M.; Van Horn, J. D.

    2014-01-01

    The integration of longitudinal brain structure analysis with neurointensive care strategies continues to be a substantial difficulty facing the traumatic brain injury (TBI) research community. For patient-tailored case analysis, it remains challenging to establish how lesion profile modulates longitudinal changes in cortical structure and connectivity, as well as how these changes lead to behavioral, cognitive and neural dysfunction. Additionally, despite the clinical potential of morphometric and connectomic studies, few analytic tools are available for their study in TBI. Here we review the state of the art in structural and connectomic neuroimaging for the study of TBI and illustrate a set of recently-developed, patient-tailored approaches for the study of TBI-related brain atrophy and alterations in morphometry as well as inter-regional connectivity. The ability of such techniques to quantify how injury modulates longitudinal changes in cortical shape, structure and circuitry is highlighted. Quantitative approaches such as these can be used to assess and monitor the clinical condition and evolution of TBI victims, and can have substantial translational impact, especially when used in conjunction with measures of neuropsychological function. PMID:24844173

  19. Crossover from ballistic to diffusive thermal transport in quantum Langevin dynamics study of a harmonic chain connected to self-consistent reservoirs

    Science.gov (United States)

    Roy, Dibyendu

    2008-06-01

    Through an exact analysis using quantum Langevin dynamics, we demonstrate the crossover from ballistic to diffusive thermal transport in a harmonic chain with each site connected to Ohmic heat reservoirs. The temperatures of the two heat baths at the boundaries are specified from the beginning, whereas the temperatures of the interior heat reservoirs are determined self-consistently by demanding that in the steady state, on average, there is no heat current between any such (self-consistent) reservoir and the harmonic chain. The essence of our study is that the effective mean free path separating the ballistic regime of transport from the diffusive one emerges naturally.

  20. Social connections and suicidal behaviour in young Australian adults: Evidence from a case–control study of persons aged 18–34 years in NSW, Australia

    Directory of Open Access Journals (Sweden)

    Allison Milner

    2015-12-01

    Conclusions: A greater number of social connections was significantly associated with reduced odds of suicide or attempt. This suggests that suicide prevention initiatives that promote increased social connections at an individual, familial, and wider social levels might be effective.

  1. Impaired Prefronto-Thalamic Functional Connectivity as a Key Feature of Treatment-Resistant Depression: A Combined MEG, PET and rTMS Study

    Science.gov (United States)

    Li, Cheng-Ta; Chen, Li-Fen; Tu, Pei-Chi; Wang, Shyh-Jen; Chen, Mu-Hong; Su, Tung-Ping; Hsieh, Jen-Chuen

    2013-01-01

    Prefrontal left-right functional imbalance and disrupted prefronto-thalamic circuitry are plausible mechanisms for treatment-resistant depression (TRD). Add-on repetitive transcranial magnetic stimulation (rTMS), effective in treating antidepressant-refractory TRD, was administered to verify the core mechanisms underlying the refractoriness to antidepressants. Thirty TRD patients received a 2-week course of 10-Hz rTMS to the left dorsolateral prefrontal cortex (DLPFC). Depression scores were evaluated at baseline (W0), and the ends of weeks 1, 2, and 14 (W14). Responders were defined as those who showed an objective improvement in depression scores ≥50% after rTMS. Left-right frontal alpha asymmetry (FAA) was measured by magnetoencephalography at each time point as a proxy for left-right functional imbalance. Prefronto-thalamic connections at W0 and W14 were assessed by studying couplings between prefrontal alpha waves and thalamic glucose metabolism (PWTMC, reflecting intact thalamo-prefrontal connectivity). A group of healthy control subjects received magnetoencephalography at W0 (N = 50) to study whether FAA could have a diagnostic value for TRD, or received both magnetoencephalography and positron-emission-tomography at W0 (N = 10) to confirm the existence of PWTMC in the depression-free state. We found that FAA changes cannot differentiate between TRD and healthy subjects or between responders and non-responders. No PWTMC were found in the TRD group at W0, whereas restitution of the PWTMC was demonstrated only in the sustained responders at W14 and euthymic healthy controls. In conclusion, we affirmed impaired prefronto-thalamic functional connections, but not frontal functional imbalance, as a core deficit in TRD. PMID:23936378

  2. EFFECT OF MAGNESIUM OROTATE ON CONNECTIVE TISSUE MATRIX AND CARDIAC INOTROPIC FUNCTION IN PATIENTS WITH MITRAL VALVE PROLAPSE. CLINICAL AND MORPHOLOGICAL STUDY

    Directory of Open Access Journals (Sweden)

    A. G. Avtandilov

    2015-09-01

    Full Text Available Aim. To study the morphological features of loose fibrous connective tissue (LFCT and myocardial contractility in patients with mitral valve prolapse before and after magnesium orotate course.Material and methods. Patients (n=59 with mitral valve prolapse and the phenotype of undifferentiated connective tissue dysplasia (UCTD were included into the study. A comprehensive morphological analysis of skin biopsy samples was performed to assess morphological and functional changes of LFCT. Standard echocardiography with the assessment of mitral flow was performed in all participants at baseline and after 8 weeks of magnesium orotate intake.Results. According to morphometry increase in proportion of amorphous matrix was found in LFCT sections after 8-week magnesium orotate course compared to baseline (38.6±0.4% and 23.9 ± 0.4%, respectively; p<0.001. According to the echocardiography increase in the end-diastolic (from 4.9±0.04 cm to 5.05±0.03 cm; p<0.05, and the end-sys- tolic (from 2.9±0.04 cm to 3.0±0.03 cm; p<0.01 left ventricular diameters was observed after 8 weeks of treatment as well as improvement of left ventricular diastolic func- tion (E/A raised from 1.42±0.02 to 1.79±0.04; p<0.01.Conclusion. In patients with mitral valve prolapse and UCTD the 8-week magnesium orotate course led to a significant increase in amorphous part of the matrix, improvement of diffusion ability and architectonics of the connective tissue that determines the improvement of flexibility and extensibility.

  3. Long-term study of grid connected photovoltaic systems in Saxony. Final report; Langzeituntersuchungen an netzgekoppelten Photovoltaikanlagen in Sachsen. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Rindelhardt, U.; Teichmann, G.; Futterschneider, H.

    1998-05-01

    Fifty small grid connected PV systems were systematically investigated between 1993 and 1997 in the frame of the 1000-Roof-Photovoltaic-Programme in Saxony. A continuous monitoring of the monthly irradiation and energy generation as well as special investigations using a new PV-system-analyzer were performed. Additionally, an extensive measuring programme was realized at 5 PV systems. The mean annual irradiation on roofs in urban regions of Saxony was estimated to be 1050 kWh/m{sup 2}. About 70% of this energy is available during the daily load peaks of the public grid in the summer months. The estimated characteristics of the main components (modules, inverters) partly showed remarkable differencies to the nominal values. A well designed and installed small PV system can reach a performance ratio of 80% and can generate a yield of 840 kWh/kW{sub p}. Future small PV systems (up to 5 kW{sub p}) are suggested to be designed as one-string-systems. The energy consumption of the participating private households was surprisingly high. A solar fraction of about 100% corresponds with a direct use of the solar energy of only 25%. The direct used solar energy increases up to 70% only at small solar fractions (<20%). (orig.) [Deutsch] Zwischen 1993 und 1997 wurden 50 kleine netzgekoppelte Photovoltaikanlagen in Sachsen im Rahmen des 1000-Daecher-Photovoltaik-Programms systematisch untersucht. Neben der kontinuierlichen Auswertung der monatlichen Einstrahlung und der Energieerzeugung wurden alle Anlagen mittels eines PV-Anlagen-Analysators vermessen. An 5 Anlagen wurde ein erweitertes Messprogramm durchgefuehrt. Die mittlere jaehrliche Einstrahlung auf geneigte Dachflaechen in urbanen Gebieten Sachsens wurde zu 1050 kWh/m{sup 2} bestimmt. Davon fallen 75% waehrend der Tageslastspitzen im Sommerhalbjahr an. Die ermittelten Kennlinien der eingesetzten Hauptkomponenten (Module, Wechselrichter) wichen teilweise erheblich von den Datenblattangaben ab. Gut ausgelegte und

  4. Influential factors on debris flow events and hillslope-channel connectivity in Alpine regions: case studies from two Alpine regions in Styria, Austria

    Science.gov (United States)

    Traper, Sandra; Pöppl, Ronald; Rascher, Eric; Sass, Oliver

    2016-04-01

    In recent times different types of natural disasters like debris flow events have attracted increasing attention worldwide, since they can cause great damage and loss of infrastructure or even lives is not unusual when it comes to such an event. The engagement with debris flows is especially important in mountainous areas like Austria, since Alpine regions have proved to be particularly prone to the often harmful consequences of such events because of increasing settlement of previously uninhabited regions. Due to those frequently damaging effects of debris flows, research on this kind of natural disaster often focuses on mitigation and recovery measures after an event and on how to restore the initial situation. However, a view on the situation of an area, where severe debris flows recently occurred and are well documented, before the actual event can aid in discovering important preparatory factors that contribute to initiating debris flows and hillslope-channel connectivity in the first place. Valuable insights into the functioning and preconditions of debris flows and their potential connectivity to the main channel can be gained. The study focuses on two geologically different areas in the Austrian Alps, which are both prone to debris flows and have experienced rather severe events recently. Based on data from debris flow events in two regions in Styria (Austria), the Kleinsölk and the Johnsbach valleys, the aim of the study is to identify factors which influence the development of debris flows and the potential of such debris flows to reach the main channel potentially clogging up the river (hillslope-channel connectivity). The degree of hillslope-channel coupling was verified in extensive TLS and ALS surveys, resulting in DEMs of different resolution and spatial extension. Those factors are obtained, analyzed and evaluated with DEM-based GIS- and statistical analyses. These include factors that are attributed to catchment topography, such as slope angle

  5. Acute caffeine administration impact on working memory-related brain activation and functional connectivity in the elderly: a BOLD and perfusion MRI study.

    Science.gov (United States)

    Haller, S; Rodriguez, C; Moser, D; Toma, S; Hofmeister, J; Sinanaj, I; Van De Ville, D; Giannakopoulos, P; Lovblad, K-O

    2013-10-10

    In young individuals, caffeine-mediated blockade of adenosine receptors and vasoconstriction has direct repercussions on task-related activations, changes in functional connectivity, as well as global vascular effects. To date, no study has explored the effect of caffeine on brain activation patterns during highly demanding cognitive tasks in the elderly. This prospective, placebo-controlled crossover design comprises 24 healthy elderly individuals (mean age 68.8 ± 4.0 years, 17 females) performing a 2-back working memory (WM) task in functional magnetic resonance imaging (fMRI). Analyses include complimentary assessment of task-related activations (general linear model, GLM), functional connectivity (tensorial independent component analysis, TICA), and baseline perfusion (arterial spin labeling). Despite a reduction in whole-brain global perfusion (-22.7%), caffeine-enhanced task-related GLM activation in a local and distributed network is most pronounced in the bilateral striatum and to a lesser degree in the right middle and inferior frontal gyrus, bilateral insula, left superior and inferior parietal lobule as well as in the cerebellum bilaterally. TICA was significantly enhanced (+8.2%) in caffeine versus placebo in a distributed and task-relevant network including the pre-frontal cortex, the supplementary motor area, the ventral premotor cortex and the parietal cortex as well as the occipital cortex (visual stimuli) and basal ganglia. The inverse comparison of placebo versus caffeine had no significant difference. Activation strength of the task-relevant-network component correlated with response accuracy for caffeine yet not for placebo, indicating a selective cognitive effect of caffeine. The present findings suggest that acute caffeine intake enhances WM-related brain activation as well as functional connectivity of blood oxygen level-dependent fMRI in elderly individuals.

  6. Modification of EEG functional connectivity and EEG power spectra in overweight and obese patients with food addiction: An eLORETA study.

    Science.gov (United States)

    Imperatori, Claudio; Fabbricatore, Mariantonietta; Innamorati, Marco; Farina, Benedetto; Quintiliani, Maria Isabella; Lamis, Dorian A; Mazzucchi, Edoardo; Contardi, Anna; Vollono, Catello; Della Marca, Giacomo

    2015-12-01

    We evaluated the modifications of electroencephalographic (EEG) power spectra and EEG connectivity in overweight and obese patients with elevated food addiction (FA) symptoms. Fourteen overweight and obese patients (3 men and 11 women) with three or more FA symptoms and fourteen overweight and obese patients (3 men and 11 women) with two or less FA symptoms were included in the study. EEG was recorded during three different conditions: 1) five minutes resting state (RS), 2) five minutes resting state after a single taste of a chocolate milkshake (ML-RS), and 3) five minutes resting state after a single taste of control neutral solution (N-RS). EEG analyses were conducted by means of the exact Low Resolution Electric Tomography software (eLORETA). Significant modification was observed only in the ML-RS condition. Compared to controls, patients with three or more FA symptoms showed an increase of delta power in the right middle frontal gyrus (Brodmann Area [BA] 8) and in the right precentral gyrus (BA 9), and theta power in the right insula (BA 13) and in the right inferior frontal gyrus (BA 47). Furthermore, compared to controls, patients with three or more FA symptoms showed an increase of functional connectivity in fronto-parietal areas in both the theta and alpha band. The increase of functional connectivity was also positively associated with the number of FA symptoms. Taken together, our results show that FA has similar neurophysiological correlates of other forms of substance-related and addictive disorders suggesting similar psychopathological mechanisms.

  7. Abnormal functional connectivity with mood regulating circuit in unmedicated individual with major depression: a resting-state functional magnetic resonance study

    Institute of Scientific and Technical Information of China (English)

    PENG Dai-hui; SHEN Ting; ZHANG Jie; HUANG Jia; LIU Jun; LIU Shu-yong; JIANG Kai-da; XU Yi-feng; FANG Yi-ru

    2012-01-01

    Background Reports on mood regulating circuit (MRC) indicated different activities between depressed patients and healthy controls.The functional networks based on MRC have not been described in major depression disorder (MDD).Both the anterior cingulate cortex (ACC) and thalamus are all the key regions of MRC.This study was to investigate the two functional networks related to ACC and thalamus in MDD.Methods Sixteen patients with MDD on first episode which never got any medication and sixteen matched health controls were scanned by 3.0 T functional magnetic resonance imaging (fMRI) during resting-state.The pregenual anterior cingulate cortex (pgACC) was used as seed region to construct the functional network by cortex section.The thalamus was used as seed region to construct the functional network by limbic section.Paired-t tests between-groups were performed for the seed-target correlations based on the individual fisher z-transformed corr