WorldWideScience

Sample records for barrier limits transmission

  1. Electron transmission through a periodically driven graphene magnetic barrier

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, R., E-mail: rbiswas.pkc@gmail.com [Department of Physics, P. K. College, Contai, Purba Medinipur, West Bengal – 721401 (India); Maiti, S. [Ajodhya Hills G.S.A.T High School, Ajodhya, Purulia, West Bengal – 723152 (India); Mukhopadhyay, S. [Purulia Zilla School, Dulmi Nadiha, Purulia, West Bengal – 723102 (India); Sinha, C. [Department of Physics, P. K. College, Contai, Purba Medinipur, West Bengal – 721401 (India); Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur – 700032 (India)

    2017-05-10

    Electronic transport through graphene magnetic barriers is studied theoretically in presence of an external time harmonic scalar potential in the framework of non-perturbative Landau–Floquet Formalism. The oscillating field mostly suppresses the transmission for rectangular magnetic barrier structure and exhibits the Fano resonance for multiphoton processes due to the presence of bound state inside the barrier. While, for a pair of delta function barriers of larger separation, the oscillating potential suppresses the usual Fabry–Perot oscillations in the transmission and a new type of asymmetric Fano resonance is noted for smaller separation, occurring due to extended states between the barriers. - Highlights: • Tunnelling of the Dirac Fermions through oscillating pure magnetic barriers is reported for the first time. • The high energy transmission through a graphene magnetic barrier is suppressed by the application of time periodic modulation. • Suppression of the Fabry Perot transmission is noted due to the application of an external time harmonic potential. • Two kinds of the Fano resonances are noted in transmission through a pair of modulated δ-function magnetic barriers.

  2. Social barriers to pathogen transmission in wild animal populations

    Energy Technology Data Exchange (ETDEWEB)

    Loehle, C.

    1995-03-01

    Diseases and pathogens are receiving increasing recognition as sources of mortality in animal populations. Immune system strength is clearly important in fending off pathogen attack. Physical barriers to pathogen entry are also important. Various individual behaviors are efficacious in reducing contact with diseases and pests. This paper focuses on a fourth mode of defense: social barriers to transmission. Various social behaviors have pathogen transmission consequences. Selective pressures on these social behaviors may therefore exist. Effects on pathogen transmission of mating strategies, social avoidance, group size, group isolation, and other behaviors are explored. It is concluded that many of these behaviors may have been affected by selection pressures to reduce transmission of pathogens. 84 refs., 1 tab.

  3. Three-humped fission barrier transmission including vibrational damping

    International Nuclear Information System (INIS)

    Calabretta, L.; Del Zoppo, A.; Ingrao, G.

    1978-01-01

    The total penetrability through a three-humped fission barrier including vibrational damping is calculated by using an optical model for fission. The Bondorf's stationary probability current theory is used for transitions among class-1, class-2 and class-3 phases. A method to calculate the partial-transmission coefficients is developed

  4. 47 CFR 73.44 - AM transmission system emission limitations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false AM transmission system emission limitations. 73... SERVICES RADIO BROADCAST SERVICES AM Broadcast Stations § 73.44 AM transmission system emission limitations. (a) The emissions of stations in the AM service shall be attenuated in accordance with the...

  5. Determination of Transmission Limits on Electric Power Systems

    Directory of Open Access Journals (Sweden)

    Castellanos-Bustamante Rafael

    2014-04-01

    Full Text Available This article provides the application of several methodologies to obtain power transmission limits through interties of the electric power systems to obtain a secure operation of the energy power system. Several aspects to obtain the maximum power flows of electrical energy thought of transmission lines on electrical grids are shown. Thermal limit of electrical conductors, loadability limit of transmission lines and small signal stability limits are obtained for several interties between geographical regions. It also, shows the application of a load shedding scheme to stabilize an interarea oscillation mode. The model of the Mexican Interconnected power System is used to illustrate these methodologies.

  6. Intrapartum practices to limit vertical transmission of HIV | du Preez ...

    African Journals Online (AJOL)

    The need to improve health services to HIV-positive women requires a specific focus on limiting mother-to-child transmission. Vertical transmission most often takes place during the intrapartum period; hence, it is essential to alert midwives to what constitutes safe or risky intrapartum practices. Midwives in the southern ...

  7. Barriers and perceived limitations to early treatment of hemophilia

    Directory of Open Access Journals (Sweden)

    Saxena K

    2013-05-01

    Full Text Available Kapil Saxena Boston Hemophilia Center, Boston Children’s Hospital, Boston, MA, USA Abstract: Early treatment of bleeds in hemophilia patients, both with and without inhibitors, has been shown to be of immense benefit in the overall clinical outcome. Despite the advantages of treating the bleeding episodes early, significant barriers and limitations remain. The aim of this review is to highlight the various barriers and perceived limitations to early therapy of bleeding episodes, especially in patients who have developed inhibitors to factor VIII. The peer-reviewed literature was searched for articles on hemophilia patients, with and without inhibitors, and early treatment, to identify the barriers to early treatment and potential impact on patient outcomes. The most important barrier is the educational barrier, which involves lack of awareness among patients regarding the signs of a bleed, as well as importance of early therapy. It is also common for parents or caregivers of school-age children to exhibit inconvenience and scheduling barriers. Distance to the treatment center can also play a role here. Some patients experience financial barriers related to cost of clotting factor products, insurance coverage, or insurance caps and out-of-pocket costs. Rarely, there can also be problems related to venous access or home infusion. Lastly, multiple psychosocial barriers can prevent adherence to treatment regimens. Identification and addressing these individual barriers will result in improved compliance rates, prevent joint damage, be more cost-effective, and lead to better overall health of these patients. Keywords: hemophilia A, hemophilia B, inhibitors, outcomes, quality of life, cost of care

  8. Quantification of the Information Limit of Transmission Electron Microscopes

    International Nuclear Information System (INIS)

    Barthel, J.; Thust, A.

    2008-01-01

    The resolving power of high-resolution transmission electron microscopes is characterized by the information limit, which reflects the size of the smallest object detail observable with a particular instrument. We introduce a highly accurate measurement method for the information limit, which is suitable for modern aberration-corrected electron microscopes. An experimental comparison with the traditionally applied Young's fringe method yields severe discrepancies and confirms theoretical considerations according to which the Young's fringe method does not reveal the information limit

  9. Intrapartum practices to limit vertical transmission of HIV | du Preez ...

    African Journals Online (AJOL)

    Accordingly, we formulate general recommendations for nursing education, future research, and midwifery practice. In particular we suggest ways the national Guidelines for Maternity Care in South Africa may be adapted and better implemented to enhance safe intrapartum practices to limit vertical transmission of HIV.

  10. Instantaneous Tunneling Flight Time for Wavepacket Transmission through Asymmetric Barriers.

    Science.gov (United States)

    Petersen, Jakob; Pollak, Eli

    2018-04-12

    The time it takes a particle to tunnel through the asymmetric Eckart barrier potential is investigated using Gaussian wavepackets, where the barrier serves as a model for the potential along a chemical reaction coordinate. We have previously shown that the, in principle experimentally measurable, tunneling flight time, which determines the time taken by the transmitted particle to traverse the barrier, vanishes for symmetric potentials like the Eckart and square barrier [ Petersen , J. ; Pollak , E. J. Phys. Chem. Lett. 2017 , 9 , 4017 ]. Here we show that the same result is obtained for the asymmetric Eckart barrier potential, and therefore, the zero tunneling flight time seems to be a general result for one-dimensional time-independent potentials. The wavepacket dynamics is simulated using both an exact quantum mechanical method and a classical Wigner prescription. The excellent agreement between the two methods shows that quantum coherences are not important in pure one-dimensional tunneling and reinforces the conclusion that the tunneling flight time vanishes.

  11. Transmission Level High Temperature Superconducting Fault Current Limiter

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Gary [SuperPower, Inc., Schenectady, NY (United States)

    2016-10-05

    The primary objective of this project was to demonstrate the feasibility and reliability of utilizing high-temperature superconducting (HTS) materials in a Transmission Level Superconducting Fault Current Limiter (SFCL) application. During the project, the type of high-temperature superconducting material used evolved from 1st generation (1G) BSCCO-2212 melt cast bulk high-temperature superconductors to 2nd generation (2G) YBCO-based high-temperature superconducting tape. The SFCL employed SuperPower's “Matrix” technology, that offers modular features to enable scale up to transmission voltage levels. The SFCL consists of individual modules that contain elements and parallel inductors that assist in carrying the current during the fault. A number of these modules are arranged in an m x n array to form the current-limiting matrix.

  12. Locational Prices in Capacity Subscription Market Considering Transmission Limitations

    Directory of Open Access Journals (Sweden)

    S. Babaeinejad Sarookolaee

    2013-06-01

    Full Text Available This study focuses on one of the most effective type of capacity markets named Capacity Subscription (CS market which is predicted to be widely used in the upcoming smart grids. Despite variant researches done about the mechanism and structure of capacity markets, their performances have been rarely tested in the presence of network constraints. Considering this deficiency, we tried to propose a new method to determine capacity prices in the network considering the transmission line flow limitations named Local capacity Prices (LP. This method is quite new and has not been tried before in any other similar researches. The philosophy of the proposed method is to determine capacity prices considering each consumer share of total peak demand. The first advantage of LP is that the consumers who benefit from the transmission facilities and are the responsible for transmission congestions, pay higher capacity prices than those whom their needed electricity is prepared locally. The second advantage of LP is that consumers connected to the same bus do not have to pay same capacity price due to their different shares of total peak demand. For more clarification, two other different methods named Branches Flow limit as a Global Limit (BFGL and Locational Capacity Prices (LCP are proposed and compared to the LP method in order to show LP method efficiency. The numerical results obtained from case studies show that the LP method follows more justice market procedure which results in more efficient capacity prices in comparison to BFGL and LCP methods.

  13. Spin-polarizated transmissivity in an asymmetrical double barrier

    International Nuclear Information System (INIS)

    Teixeira, J D S; Frota, H O; Bittencourt, A C R

    2014-01-01

    The spin-polarized electron resonant tunnelling at zero magnetic field through a double barrier heterostructure like InAs/GaSb/InAs/GaSb/InAs has been calculated as a function of the electron energy. A model is proposed to study the combined effects of Dresselhaus and in-plane Rashba spin-orbit interactions on the spin-dependent tunnelling, taking into account the k 3 dependence of the Dresselhaus Hamiltonian. For the directions ϕ=45 ∘ and 135 ∘ the spin mixing produces a 100% efficiency of polarization. Moreover, the effect of the Dresselhaus and Rashba spin-orbit interactions are shown to be quite favorable for the fabrication of spin filters and spintronic devices. (paper)

  14. Use of element model to evaluate transmissibility reduction due to barriers

    Energy Technology Data Exchange (ETDEWEB)

    Svanes, T.; South, D.; Dronen, O.M. [Statoil, Bergen (Norway)

    1997-08-01

    Water breakthrough has been observed a year earlier than expected in the productive Oseberg Formation in the Veslefrikk Field. Production data revealed extensive water override, whereas the opposite situation was expected based on a homogeneous and coarse flow simulation model. A new model was developed to include geological heterogeneities using a simple upscaling method. The Oseberg Fm. consists of an upper homogeneous unit (zone 2) and a lower unit containing thin barriers of shale and calcite cemented sandstone (zone 1). The barrier content varies laterally. When barriers are distributed in a complex 3D pattern, they reduce the upscaled horizontal transmissibility more than what is obtained by multiplying the sand permeability by the net-to-gross ratio (N/G). However, the transmissibility reduction strongly depends on the spatial distribution of barriers and their geometry. Therefore, a fine scale element model was used to derive the average transmissibility reduction as a function of N/G for alternative geological descriptions of the barriers. A geo-statistical method called General Marked Point Process was used to generate the fine scale descriptions. This work has resulted in a simple upscaling routine for horizontal transmissibility, which represents an effective bridge between geological evaluation of uncertainties and fluid flow simulation. The method combines geo-statistical and deterministic modelling in an elegant manner, recognising that most often these methods complement one another.

  15. Ballistic charge carrier transmission through graphene multi-barrier structures in uniform magnetic field

    International Nuclear Information System (INIS)

    Zubarev, A; Dragoman, D

    2014-01-01

    We investigate charge carrier transport in graphene multi-barrier structures placed in a uniform magnetic field. The transmission coefficient is found analytically by generalizing the transfer matrix method for the case of graphene regions subjected to a uniform magnetic field. The transmission coefficient through the structure can be modulated by varying the gate voltages, the magnetic field and/or the width of the gated regions. Such a configuration could be used in multiple-valued logic circuits, since it has several output states with discrete and easily selectable transmission/current values. (paper)

  16. A novel nanoscaled Schottky barrier based transmission gate and its digital circuit applications

    Science.gov (United States)

    Kumar, Sunil; Loan, Sajad A.; Alamoud, Abdulrahman M.

    2017-04-01

    In this work we propose and simulate a compact nanoscaled transmission gate (TG) employing a single Schottky barrier based transistor in the transmission path and a single transistor based Sajad-Sunil-Schottky (SSS) device as an inverter. Therefore, just two transistors are employed to realize a complete transmission gate which normally consumes four transistors in the conventional technology. The transistors used to realize the transmission path and the SSS inverter in the proposed TG are the double gate Schottky barrier devices, employing stacks of two metal silicides, platinum silicide (PtSi) and erbium silicide (ErSi). It has been observed that the realization of the TG gate by the proposed technology has resulted into a compact structure, with reduced component count, junctions, interconnections and regions in comparison to the conventional technology. The further focus of this work is on the application part of the proposed technology. So for the first time, the proposed technology has been used to realize various combinational circuits, like a two input AND gate, a 2:1 multiplexer and a two input XOR circuits. It has been observed that the transistor count has got reduced by half in a TG, two input AND gate, 2:1 multiplexer and in a two input XOR gate. Therefore, a significant reduction in transistor count and area requirement can be achieved by using the proposed technology. The proposed technology can be also used to perform the compact realization of other combinational and sequential circuitry in future.

  17. 75 FR 18497 - Guidance on Simultaneous Transmission Import Limit Studies for the Northwest Region; Notice of...

    Science.gov (United States)

    2010-04-12

    ... Simultaneous Transmission Import Limit Studies for the Northwest Region; Notice of Pre-Filing Technical Conference for Northwest Region Transmission Owners April 5, 2010. Take notice that Commission staff will... purpose of the conference is to give transmission owners in the Northwest region an opportunity to ask...

  18. Toll-like receptor 4 limits transmission of Bordetella bronchiseptica.

    Directory of Open Access Journals (Sweden)

    Olivier Rolin

    Full Text Available Transmission of pathogens has been notoriously difficult to study under laboratory conditions leaving knowledge gaps regarding how bacterial factors and host immune components affect the spread of infections between hosts. We describe the development of a mouse model of transmission of a natural pathogen, Bordetella bronchiseptica, and its use to assess the impact of host immune functions. Although B. bronchiseptica transmits poorly between wild-type mice and mice lacking other immune components, it transmits efficiently between mice deficient in Toll-Like Receptor 4 (TLR4. TLR4-mutant mice were more susceptible to initial colonization, and poorly controlled pathogen growth and shedding. Heavy neutrophil infiltration distinguished TLR4-deficient responses, and neutrophil depletion did not affect respiratory CFU load, but decreased bacterial shedding. The effect of TLR4 response on transmission may explain the extensive variation in TLR4 agonist potency observed among closely related subspecies of Bordetella. This transmission model will enable mechanistic studies of how pathogens spread from one host to another, the defining feature of infectious disease.

  19. Testing the physiological barriers to viral transmission in aphids using microinjection.

    Science.gov (United States)

    Tamborindeguy, Cecilia; Gray, Stewart; Jander, Georg

    2008-05-14

    Potato loafroll virus (PLRV), from the family Luteoviridae infects solanaceous plants. It is transmitted by aphids, primarily, the green peach aphid. When an uninfected aphid feeds on an infected plant it contracts the virus through the plant phloem. Once ingested, the virus must pass from the insect gut to the hemolymph (the insect blood ) and then must pass through the salivary gland, in order to be transmitted back to a new plant. An aphid may take up different viruses when munching on a plant, however only a small fraction will pass through the gut and salivary gland, the two main barriers for transmission to infect more plants. In the lab, we use physalis plants to study PLRV transmission. In this host, symptoms are characterized by stunting and interveinal chlorosis (yellowing of the leaves between the veins with the veins remaining green). The video that we present demonstrates a method for performing aphid microinjection on insects that do not vector PLVR viruses and tests whether the gut is preventing viral transmission. The video that we present demonstrates a method for performing Aphid microinjection on insects that do not vector PLVR viruses and tests whether the gut or salivary gland is preventing viral transmission.

  20. Technical Barriers, Licenses and Tariffs as Means of Limiting Market Access

    DEFF Research Database (Denmark)

    Schröder, Philipp J.H.; Jørgensen, Jan Guldager

    2006-01-01

    accessing the domestic market, a technical barrier (an import license) may dominate a tariff (tariff and a tech- nical barrier) in terms of consumer welfare, even when tariff revenues are fully redistributed. However, if protection pays su±cient focus on limiting the total import volume, then tariffs......Technical barriers (standards), import licenses and tariffs may be deployed as means of limiting the market access of foreign firms. The present paper examines these measures in a setting of monopolistic competition. We find that, if protection focuses predominantly on the number of foreign firms...

  1. Reduced Water Vapor Transmission Rate of Graphene Gas Barrier Films for Flexible Organic Field-Effect Transistors.

    Science.gov (United States)

    Choi, Kyoungjun; Nam, Sooji; Lee, Youngbin; Lee, Mijin; Jang, Jaeyoung; Kim, Sang Jin; Jeong, Yong Jin; Kim, Hyeongkeun; Bae, Sukang; Yoo, Ji-Beom; Cho, Sung M; Choi, Jae-Boong; Chung, Ho Kyoon; Ahn, Jong-Hyun; Park, Chan Eon; Hong, Byung Hee

    2015-06-23

    Preventing reactive gas species such as oxygen or water is important to ensure the stability and durability of organic electronics. Although inorganic materials have been predominantly employed as the protective layers, their poor mechanical property has hindered the practical application to flexible electronics. The densely packed hexagonal lattice of carbon atoms in graphene does not allow the transmission of small gas molecules. In addition, its outstanding mechanical flexibility and optical transmittance are expected to be useful to overcome the current mechanical limit of the inorganic materials. In this paper, we reported the measurement of the water vapor transmission rate (WVTR) through the 6-layer 10 × 10 cm(2) large-area graphene films synthesized by chemical vapor deposition (CVD). The WVTR was measured to be as low as 10(-4) g/m(2)·day initially, and stabilized at ∼0.48 g/m(2)·day, which corresponds to 7 times reduction in WVTR compared to bare polymer substrates. We also showed that the graphene-passivated organic field-effect transistors (OFETs) exhibited excellent environmental stability as well as a prolonged lifetime even after 500 bending cycles with strain of 2.3%. We expect that our results would be a good reference showing the graphene's potential as gas barriers for organic electronics.

  2. On cluster ions, ion transmission, and linear dynamic range limitations in electrospray (ionspray) mass spectrometry

    NARCIS (Netherlands)

    Zook, D.R; Bruins, A.P.

    The ion transmission in Electrospray (Ionspray) Mass Spectrometry (ESMS) was studied in order to examine the instrumental factors potentially contributing to observed ESMS linear dynamic range (LDR) limitations. A variety of means used for the investigation of ion transmission demonstrated that a

  3. A qualitative case study to identify possible barriers that limit effective elementary science education

    Science.gov (United States)

    Foster, Donald Carey

    The purpose of this case study was to identify barriers that limit the effectiveness of elementary teachers in the teaching of science. It is of the utmost urgency that barriers be first identified, so that possible solutions can be explored to bring about the improvement of elementary science education. This urgency has been imposed by the scheduled national testing of students in science by 2007, as mandated by the No Child Left Behind Act of 2001. Using qualitative case study methods, the researcher conducted interviews with 8 elementary teachers from two schools within one school district who taught 3rd, 4th, and 5th grade. These interviews were designed to gain insight into barriers these elementary teachers perceived as factors limiting their effectiveness in teaching science and preparing students for high-stakes testing. Barriers in the areas of teacher background, typical teaching day, curriculum, inservices, and legislative influences were explored. This study concluded that the barriers explored do have a substantial negative affect on the teaching and learning of science in the elementary grades. Specifically, the barriers revealed in this study include the limited science background of elementary teachers, inadequate class time devoted to science, non-comprehensive curriculum, ineffective or lack of inservice training, and pressures from legislated mandates. But it is also clear that these barriers are so intertwined that one cannot remove these barriers one at a time. It will take a collective effort from all involved, including legislators, administrators, teachers, parents, and students, to alleviate these barriers and discover effective solutions to improve elementary science education.

  4. Attempting to be active: Self-efficacy and barrier limitation differentiate activity levels of working mothers.

    Science.gov (United States)

    Gierc, Madelaine; Locke, Sean; Jung, Mary; Brawley, Lawrence

    2016-07-01

    Working mothers are less physically active than working women without children and mothers who do not work. The purpose of this study was to examine concurrent self-regulatory efficacy and barriers to physical activity in a sample of working mothers. Women completed a mixed-methods survey which included measures of physical activity, concurrent self-regulatory efficacy, and barriers. Sufficiently active women experienced significantly greater concurrent self-regulatory efficacy and significantly less barrier limitation and frequency. No significant group differences were found for age, domestic duties performed, and children's extracurricular activities. Thematic analysis of barriers revealed six themes of common and unique factors, including limited time and family activities. © The Author(s) 2014.

  5. Technical barriers, import licenses and tariffs as means of limiting market access

    DEFF Research Database (Denmark)

    Jørgensen, Jan G.; Schröder, Philipp

    2003-01-01

    Technical barriers (standards), import licenses and tariffs may be deployed as means of limiting the market entry of foreign firms. The present paper examines these measures in a setting of monopolistic competition. It is established that -- contrary to what one would expect -- a technical barrier...... to trade can dominate a tariff in terms of consumer welfare, even when tariff revenues are fully redistributed. This case occurs for high levels of protection. Furthermore, an import license with full redistribution of revenues dominates both the technical barrier and the tariff for all levels...

  6. The limitation of the Slew Rate, as attenuator of effects of transmission line

    International Nuclear Information System (INIS)

    Rodriguez V, Luis Alfonso; Lopez Q, Jose German

    1999-01-01

    Transmission line effects in circuits of all kinds are becoming more notorious due to increased speeds of the signals traveling through them and also because of the circuits, which act upon them. A technique which is ready available to minimize the unwanted effects of transmission line behavior on the part of the circuits and lines involved, is to limit the Slew - Rate of the drivers used throughout. This paper undertakes an analysis of such a technique from the standpoint of frequencies as far as the benefits accrued from the used of slew rate limiting in the presence of transmission line effects

  7. Physiologic upper limit of pore size in the blood-tumor barrier of malignant solid tumors

    Directory of Open Access Journals (Sweden)

    Griffiths Gary L

    2009-06-01

    Full Text Available Abstract Background The existence of large pores in the blood-tumor barrier (BTB of malignant solid tumor microvasculature makes the blood-tumor barrier more permeable to macromolecules than the endothelial barrier of most normal tissue microvasculature. The BTB of malignant solid tumors growing outside the brain, in peripheral tissues, is more permeable than that of similar tumors growing inside the brain. This has been previously attributed to the larger anatomic sizes of the pores within the BTB of peripheral tumors. Since in the physiological state in vivo a fibrous glycocalyx layer coats the pores of the BTB, it is possible that the effective physiologic pore size in the BTB of brain tumors and peripheral tumors is similar. If this were the case, then the higher permeability of the BTB of peripheral tumor would be attributable to the presence of a greater number of pores in the BTB of peripheral tumors. In this study, we probed in vivo the upper limit of pore size in the BTB of rodent malignant gliomas grown inside the brain, the orthotopic site, as well as outside the brain in temporalis skeletal muscle, the ectopic site. Methods Generation 5 (G5 through generation 8 (G8 polyamidoamine dendrimers were labeled with gadolinium (Gd-diethyltriaminepentaacetic acid, an anionic MRI contrast agent. The respective Gd-dendrimer generations were visualized in vitro by scanning transmission electron microscopy. Following intravenous infusion of the respective Gd-dendrimer generations (Gd-G5, N = 6; Gd-G6, N = 6; Gd-G7, N = 5; Gd-G8, N = 5 the blood and tumor tissue pharmacokinetics of the Gd-dendrimer generations were visualized in vivo over 600 to 700 minutes by dynamic contrast-enhanced MRI. One additional animal was imaged in each Gd-dendrimer generation group for 175 minutes under continuous anesthesia for the creation of voxel-by-voxel Gd concentration maps. Results The estimated diameters of Gd-G7 dendrimers were 11 ± 1 nm and those of Gd-G8

  8. Risk Factors for HIV Transmission and Barriers to HIV Disclosure: Metropolitan Atlanta Youth Perspectives.

    Science.gov (United States)

    Camacho-Gonzalez, Andres F; Wallins, Amy; Toledo, Lauren; Murray, Ashley; Gaul, Zaneta; Sutton, Madeline Y; Gillespie, Scott; Leong, Traci; Graves, Chanda; Chakraborty, Rana

    2016-01-01

    Youth carry the highest incidence of HIV infection in the United States. Understanding adolescent and young adult (AYA) perspectives on HIV transmission risk is important for targeted HIV prevention. We conducted a mixed methods study with HIV-infected and uninfected youth, ages 18-24 years, from Atlanta, GA. We provided self-administered surveys to HIV-infected and HIV-uninfected AYAs to identify risk factors for HIV acquisition. By means of computer-assisted thematic analyses, we examined transcribed focus group responses on HIV education, contributors to HIV transmission, and pre-sex HIV status disclosure. The 68 participants had the following characteristics: mean age 21.5 years (standard deviation: 1.8 years), 85% male, 90% black, 68% HIV-infected. HIV risk behaviors included the perception of condomless sex (Likert scale mean: 8.0) and transactional sex (88% of participants); no differences were noted by HIV status. Qualitative analyses revealed two main themes: (1) HIV risk factors among AYAs, and (2) barriers to discussing HIV status before sex. Participants felt the use of social media, need for immediate gratification, and lack of concern about HIV disease were risk factors for AYAs. Discussing HIV status with sex partners was uncommon. Key reasons included: fear of rejection, lack of confidentiality, discussion was unnecessary in temporary relationships, and disclosure negatively affecting the mood. HIV prevention strategies for AYAs should include improving condom use frequency and HIV disclosure skills, responsible utilization of social media, and education addressing HIV prevention including the risks of transactional sex.

  9. Estimating Employment Effects of Powerlinks Transmission Limited Project in India and Bhutan

    OpenAIRE

    International Finance Corporation

    2012-01-01

    In 2003 International Finance Corporation (IFC) committed a loan of US $75 million to Powerlinks Transmission Limited (PTL) a joint venture company, to construct power transmission lines that helped evacuate hydropower from Bhutan to a number of States in north and east India. Unlike most studies which tend to focus on jobs created through construction and O&M (category one jobs) of power projects, this study looks at employment effects more comprehensively and also estimates category two jo...

  10. A variational centroid density procedure for the calculation of transmission coefficients for asymmetric barriers at low temperature

    International Nuclear Information System (INIS)

    Messina, M.; Schenter, G.K.; Garrett, B.C.

    1995-01-01

    The low temperature behavior of the centroid density method of Voth, Chandler, and Miller (VCM) [J. Chem. Phys. 91, 7749 (1989)] is investigated for tunneling through a one-dimensional barrier. We find that the bottleneck for a quantum activated process as defined by VCM does not correspond to the classical bottleneck for the case of an asymmetric barrier. If the centroid density is constrained to be at the classical bottleneck for an asymmetric barrier, the centroid density method can give transmission coefficients that are too large by as much as five orders of magnitude. We follow a variational procedure, as suggested by VCM, whereby the best transmission coefficient is found by varying the position of the centroid until the minimum value for this transmission coefficient is obtained. This is a procedure that is readily generalizable to multidimensional systems. We present calculations on several test systems which show that this variational procedure greatly enhances the accuracy of the centroid density method compared to when the centroid is constrained to be at the barrier top. Furthermore, the relation of this procedure to the low temperature periodic orbit or ''instanton'' approach is discussed. copyright 1995 American Institute of Physics

  11. Barrier Performance of CVD Graphene Films Using a Facile P3HT Thin Film Optical Transmission Test

    Directory of Open Access Journals (Sweden)

    Srinivasa Kartik Nemani

    2018-01-01

    Full Text Available The barrier performance of CVD graphene films was determined using a poly(3-hexylthiophene (P3HT thin film optical transmission test. P3HT is a semiconducting polymer that photo-oxidatively degrades upon exposure to oxygen and light. The polymer is stable under ambient conditions and indoor lighting, enabling P3HT films to be deposited and encapsulated in air. P3HT’s stability under ambient conditions makes it desirable for an initial evaluation of barrier materials as a complimentary screening method in combination with conventional barrier tests. The P3HT test was used to demonstrate improved barrier performance for polymer substrates after addition of CVD graphene films. A layer-by-layer transfer method was utilized to enhance the barrier performance of monolayer graphene. Another set of absorption measurements were conducted to demonstrate the barrier performance of graphene and the degradation mechanism of graphene/P3HT over multiple wavelengths from 400 to 800 nm. The absorption spectra for graphene/polymer composite were simulated by solving Fresnel equations. The simulation results were found to be in good agreement with the measured absorption spectra. The P3HT degradation results qualitatively indicate the potential of graphene films as a possible candidate for medium performance barriers.

  12. CITY TRANSPORT IN BARRIER-FREE ARCHITECTURAL PLANNING SPACE FOR PEOPLE WITH LIMITED MOBILITY

    Directory of Open Access Journals (Sweden)

    Pryadko Igor’ Petrovich

    2014-09-01

    Full Text Available This paper reviews the current state of transport organization for people with limited mobility. The article evaluates the results of the actions the executive authorities of Moscow and Moscow Region take. Barrier-free space organization for disabled people and parents with prams is given a special attention. The lack of strategy in the sphere leads to considerable difficulties for people with limited ability. This problem should be solved in cooperation with the survey of other peoples' needs. The article gives examples of comfortable urban space in Sochi, Moscow, Chita, Mytishchi and analyses the ways urbanism influences people with limited abilities.

  13. Detection of a contact barrier by a temperature-modulated space-charge-limited current technique

    Czech Academy of Sciences Publication Activity Database

    Zhivkov, I.; Biler, M.; Nešpůrek, Stanislav

    2007-01-01

    Roč. 9, č. 2 (2007), s. 483-485 ISSN 1454-4164. [International School on Condensed Matter Physics /14./. Varna, 17.09.2006-22.09.2006] R&D Projects: GA MŠk OC 138 Institutional research plan: CEZ:AV0Z40500505 Keywords : poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene] vinylene * space-charge-limited current * Schottky barrier Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.827, year: 2007

  14. Compressive sensing imaging through a drywall barrier at sub-THz and THz frequencies in transmission and reflection modes

    Science.gov (United States)

    Takan, Taylan; Özkan, Vedat A.; Idikut, Fırat; Yildirim, Ihsan Ozan; Şahin, Asaf B.; Altan, Hakan

    2014-10-01

    In this work sub-terahertz imaging using Compressive Sensing (CS) techniques for targets placed behind a visibly opaque barrier is demonstrated both experimentally and theoretically. Using a multiplied Schottky diode based millimeter wave source working at 118 GHz, metal cutout targets were illuminated in both reflection and transmission configurations with and without barriers which were made out of drywall. In both modes the image is spatially discretized using laser machined, 10 × 10 pixel metal apertures to demonstrate the technique of compressive sensing. The images were collected by modulating the source and measuring the transmitted flux through the apertures using a Golay cell. Experimental results were compared to simulations of the expected transmission through the metal apertures. Image quality decreases as expected when going from the non-obscured transmission case to the obscured transmission case and finally to the obscured reflection case. However, in all instances the image appears below the Nyquist rate which demonstrates that this technique is a viable option for Through the Wall Reflection Imaging (TWRI) applications.

  15. Prevention of vertical transmission of HIV-1 in resource-limited settings.

    Science.gov (United States)

    Coutsoudis, Anna; Kwaan, Leith; Thomson, Mairi

    2010-10-01

    One of the most exciting areas of HIV research is that of prevention of vertical transmission from mother to child, since it accounts for 90% of childhood HIV infections, and therefore prevention in this context has an enormous potential impact on the spread of HIV among children. Focused research has yielded highly successful strategies for reducing infant infection rates, particularly in the developed world, and much work is underway to implement appropriate strategies in resource-limited settings, although this is not without challenges. Although transmission rates in some settings have been reduced to approximately 1%, scale-up and widespread implementation and application of strategic interventions for prevention of mother-to-child transmission of HIV during pregnancy, delivery and breastfeeding are needed in the developing world.

  16. Structural and Psycho-Social Limits to Climate Change Adaptation in the Great Barrier Reef Region.

    Directory of Open Access Journals (Sweden)

    Louisa S Evans

    Full Text Available Adaptation, as a strategy to respond to climate change, has limits: there are conditions under which adaptation strategies fail to alleviate impacts from climate change. Research has primarily focused on identifying absolute bio-physical limits. This paper contributes empirical insight to an emerging literature on the social limits to adaptation. Such limits arise from the ways in which societies perceive, experience and respond to climate change. Using qualitative data from multi-stakeholder workshops and key-informant interviews with representatives of the fisheries and tourism sectors of the Great Barrier Reef region, we identify psycho-social and structural limits associated with key adaptation strategies, and examine how these are perceived as more or less absolute across levels of organisation. We find that actors experience social limits to adaptation when: i the effort of pursuing a strategy exceeds the benefits of desired adaptation outcomes; ii the particular strategy does not address the actual source of vulnerability, and; iii the benefits derived from adaptation are undermined by external factors. We also find that social limits are not necessarily more absolute at higher levels of organisation: respondents perceived considerable opportunities to address some psycho-social limits at the national-international interface, while they considered some social limits at the local and regional levels to be effectively absolute.

  17. Structural and Psycho-Social Limits to Climate Change Adaptation in the Great Barrier Reef Region.

    Science.gov (United States)

    Evans, Louisa S; Hicks, Christina C; Adger, W Neil; Barnett, Jon; Perry, Allison L; Fidelman, Pedro; Tobin, Renae

    2016-01-01

    Adaptation, as a strategy to respond to climate change, has limits: there are conditions under which adaptation strategies fail to alleviate impacts from climate change. Research has primarily focused on identifying absolute bio-physical limits. This paper contributes empirical insight to an emerging literature on the social limits to adaptation. Such limits arise from the ways in which societies perceive, experience and respond to climate change. Using qualitative data from multi-stakeholder workshops and key-informant interviews with representatives of the fisheries and tourism sectors of the Great Barrier Reef region, we identify psycho-social and structural limits associated with key adaptation strategies, and examine how these are perceived as more or less absolute across levels of organisation. We find that actors experience social limits to adaptation when: i) the effort of pursuing a strategy exceeds the benefits of desired adaptation outcomes; ii) the particular strategy does not address the actual source of vulnerability, and; iii) the benefits derived from adaptation are undermined by external factors. We also find that social limits are not necessarily more absolute at higher levels of organisation: respondents perceived considerable opportunities to address some psycho-social limits at the national-international interface, while they considered some social limits at the local and regional levels to be effectively absolute.

  18. Structural and Psycho-Social Limits to Climate Change Adaptation in the Great Barrier Reef Region

    Science.gov (United States)

    Evans, Louisa S.; Hicks, Christina C.; Adger, W. Neil; Barnett, Jon; Perry, Allison L.; Fidelman, Pedro; Tobin, Renae

    2016-01-01

    Adaptation, as a strategy to respond to climate change, has limits: there are conditions under which adaptation strategies fail to alleviate impacts from climate change. Research has primarily focused on identifying absolute bio-physical limits. This paper contributes empirical insight to an emerging literature on the social limits to adaptation. Such limits arise from the ways in which societies perceive, experience and respond to climate change. Using qualitative data from multi-stakeholder workshops and key-informant interviews with representatives of the fisheries and tourism sectors of the Great Barrier Reef region, we identify psycho-social and structural limits associated with key adaptation strategies, and examine how these are perceived as more or less absolute across levels of organisation. We find that actors experience social limits to adaptation when: i) the effort of pursuing a strategy exceeds the benefits of desired adaptation outcomes; ii) the particular strategy does not address the actual source of vulnerability, and; iii) the benefits derived from adaptation are undermined by external factors. We also find that social limits are not necessarily more absolute at higher levels of organisation: respondents perceived considerable opportunities to address some psycho-social limits at the national-international interface, while they considered some social limits at the local and regional levels to be effectively absolute. PMID:26960200

  19. Analysis of Optical CDMA Signal Transmission: Capacity Limits and Simulation Results

    Directory of Open Access Journals (Sweden)

    Lawrence R. Chen

    2005-06-01

    Full Text Available We present performance limits of the optical code-division multiple-access (OCDMA networks. In particular, we evaluate the information-theoretical capacity of the OCDMA transmission when single-user detection (SUD is used by the receiver. First, we model the OCDMA transmission as a discrete memoryless channel, evaluate its capacity when binary modulation is used in the interference-limited (noiseless case, and extend this analysis to the case when additive white Gaussian noise (AWGN is corrupting the received signals. Next, we analyze the benefits of using nonbinary signaling for increasing the throughput of optical CDMA transmission. It turns out that up to a fourfold increase in the network throughput can be achieved with practical numbers of modulation levels in comparison to the traditionally considered binary case. Finally, we present BER simulation results for channel coded binary and M-ary OCDMA transmission systems. In particular, we apply turbo codes concatenated with Reed-Solomon codes so that up to several hundred concurrent optical CDMA users can be supported at low target bit error rates. We observe that unlike conventional OCDMA systems, turbo-empowered OCDMA can allow overloading (more active users than is the length of the spreading sequences with good bit error rate system performance.

  20. Analysis of Optical CDMA Signal Transmission: Capacity Limits and Simulation Results

    Science.gov (United States)

    Garba, Aminata A.; Yim, Raymond M. H.; Bajcsy, Jan; Chen, Lawrence R.

    2005-12-01

    We present performance limits of the optical code-division multiple-access (OCDMA) networks. In particular, we evaluate the information-theoretical capacity of the OCDMA transmission when single-user detection (SUD) is used by the receiver. First, we model the OCDMA transmission as a discrete memoryless channel, evaluate its capacity when binary modulation is used in the interference-limited (noiseless) case, and extend this analysis to the case when additive white Gaussian noise (AWGN) is corrupting the received signals. Next, we analyze the benefits of using nonbinary signaling for increasing the throughput of optical CDMA transmission. It turns out that up to a fourfold increase in the network throughput can be achieved with practical numbers of modulation levels in comparison to the traditionally considered binary case. Finally, we present BER simulation results for channel coded binary and[InlineEquation not available: see fulltext.]-ary OCDMA transmission systems. In particular, we apply turbo codes concatenated with Reed-Solomon codes so that up to several hundred concurrent optical CDMA users can be supported at low target bit error rates. We observe that unlike conventional OCDMA systems, turbo-empowered OCDMA can allow overloading (more active users than is the length of the spreading sequences) with good bit error rate system performance.

  1. Internal transport barrier and β limit in ohmically heated plasma in TUMAN-3M

    International Nuclear Information System (INIS)

    Andreiko, M.V.; Askinazi, L.G.; Golant, V.E.

    2001-01-01

    An Internal Transport Barrier (ITB) was found in ohmically heated plasma in TUMAN-3M (R 0 =53 cm, a l =22 cm - circular limiter configuration, B t ≤0.7T, I p ≤175 kA, ≤6.0·10 19 m -3 ). The barrier reveals itself as a formation of a steep gradient on electron temperature and density radial profiles. The regions with reduced diffusion and electron thermal diffusivity are in between r=0.5a and r=0.7a. The ITB appears more frequently in the shots with higher plasma current. At lower currents (I p N limit in the ohmically heated plasma are presented. Stored energy was measured using diamagnetic loops and compared with W calculated from kinetic data obtained by Thomson scattering and microwave interferometry. Measurements of the stored energy and of the β were performed in the ohmic H-mode before and after boronization and in the scenario with the fast Current Ramp-Down in the ohmic H-mode. Maximum value of β T of 2.0 % and β N of 2 were achieved. The β N limit achieved is 'soft' (nondisruptive) limit. The stored energy slowly decays after the Current Ramp-Down. No correlation was found between beta restriction and MHD phenomena. (author)

  2. Internal transport barrier and β limit in ohmically heated plasma in TUMAN-3M

    International Nuclear Information System (INIS)

    Andreiko, M.V.; Askinazi, L.G.; Golant, V.E.

    1999-01-01

    An Internal Transport Barrier (ITB) was found in ohmically heated plasma in TUMAN-3M (R 0 = 53 cm, a l = 22 cm - circular limiter configuration, B t ≤ 0.7 T, I p ≤ 175 kA, ≤ 6.0·10 19 m -3 ). The barrier reveals itself as a formation of a steep gradient on electron temperature and density radial profiles. The regions with reduced diffusion and electron thermal diffusivity are in between r = 0.5a and r = 0.7a. The ITB appears more frequently in the shots with higher plasma current. At lower currents (I p N limit in the ohmically heated plasma are presented. Stored energy was measured using diamagnetic loops and compared with W calculated from kinetic data obtained by Thomson scattering and microwave interferometry. Measurements of the stored energy and of the β were performed in the ohmic H-mode before and after boronization and in the scenario with the fast Current Ramp-Down in the ohmic H-mode. Maximum value of β T of 2.0% and β N of 2 were achieved. The β N limit achieved is 'soft' (non-disruptive) limit. The stored energy slowly decays after the Current Ramp-Down. No correlation was found between beta restriction and MHD phenomena. (author)

  3. Benefits, barriers, and limitations on the use of Hospital Incident Command System

    Directory of Open Access Journals (Sweden)

    Shahin Shooshtari

    2017-01-01

    Full Text Available Hospital Incident Command System (HICS has been established with the mission of prevention, response, and recovery in hazards. Regarding the key role of hospitals in medical management of events, the present study is aimed at investigating benefits, barriers, and limitations of applying HICS in hospital. Employing a review study, articles related to the aforementioned subject published from 1995 to 2016 were extracted from accredited websites and databases such as PubMed, Google Scholar, Elsevier, and SID by searching keywords such as HICS, benefits, barriers, and limitations. Then, those articles were summarized and reported. Using of HICS can cause creating preparedness in facing disasters, constructive management in strategies of controlling events, and disasters. Therefore, experiences indicate that there are some limitations in the system such as failure to assess the strength and severity of vulnerabilities of hospital, no observation of standards for disaster management in the design, constructing and equipping hospitals, and the absence of a model for evaluating the system. Accordingly, the conducted studies were investigated for probing the performance HICS. With regard to the role of health in disaster management, it requires advanced international methods in facing disasters. Using accurate models for assessing, the investigation of preparedness of hospitals in precrisis conditions based on components such as command, communications, security, safety, development of action plans, changes in staff's attitudes through effective operational training and exercises and creation of required maneuvers seems necessary.

  4. 77 FR 73646 - Essar Steel Minnesota, LLC v. Great Lakes Gas Transmission Limited Partnership; Notice of Complaint

    Science.gov (United States)

    2012-12-11

    ... Transmission Limited Partnership (Respondent), alleging that the Respondent has failed to comply with the... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. RP13-313-000] Essar Steel Minnesota, LLC v. Great Lakes Gas Transmission Limited Partnership; Notice of Complaint Take notice that on...

  5. Synchronization in Array of Coupled Neural Networks with Unbounded Distributed Delay and Limited Transmission Efficiency

    Directory of Open Access Journals (Sweden)

    Xinsong Yang

    2013-01-01

    Full Text Available This paper investigates global synchronization in an array of coupled neural networks with time-varying delays and unbounded distributed delays. In the coupled neural networks, limited transmission efficiency between coupled nodes, which makes the model more practical, is considered. Based on a novel integral inequality and the Lyapunov functional method, sufficient synchronization criteria are derived. The derived synchronization criteria are formulated by linear matrix inequalities (LMIs and can be easily verified by using Matlab LMI Toolbox. It is displayed that, when some of the transmission efficiencies are limited, the dynamics of the synchronized state are different from those of the isolated node. Furthermore, the transmission efficiency and inner coupling matrices between nodes play important roles in the final synchronized state. The derivative of the time-varying delay can be any given value, and the time-varying delay can be unbounded. The outer-coupling matrices can be symmetric or asymmetric. Numerical simulations are finally given to demonstrate the effectiveness of the theoretical results.

  6. A high-performance ultrasonic system for the simultaneous transmission of data and power through solid metal barriers.

    Science.gov (United States)

    Lawry, Tristan J; Wilt, Kyle R; Ashdown, Jon D; Scarton, Henry A; Saulnier, Gary J

    2013-01-01

    This paper presents a system capable of simultaneous high-power and high-data-rate transmission through solid metal barriers using ultrasound. By coaxially aligning a pair of piezoelectric transducers on opposite sides of a metal wall and acoustically coupling them to the barrier, an acoustic- electric transmission channel is formed which prevents the need for physical penetration. Independent data and power channels are utilized, but they are only separated by 25.4 mm to reduce the system's form factor. Commercial off-the-shelf components and evaluation boards are used to create realtime prototype hardware and the full system is capable of transmitting data at 17.37 Mbps and delivering 50 W of power through a 63.5-mm thick steel wall. A synchronous multi-carrier communication scheme (OFDM) is used to achieve a very high spectral efficiency and to ensure that there is only minor interference between the power and data channels. Also presented is a discussion of potential enhancements that could be made to greatly improve the power and data-rate capabilities of the system. This system could have a tremendous impact on improving safety and preserving structural integrity in many military applications (submarines, surface ships, unmanned undersea vehicles, armored vehicles, planes, etc.) as well as in a wide range of commercial, industrial, and nuclear systems.

  7. Social and behavioral barriers to pathogen transmission in wild animal populations

    Energy Technology Data Exchange (ETDEWEB)

    Loehle, C.S.

    1988-12-31

    Disease and pathogens have been studied as regulators of animal populations but not really as selective forces. The authors propose that pathogens can be major selective forces influencing social behaviors when these are successful at reducing disease transmission. The behaviors whose evolution could have been influenced by pathogen effects include group size, group isolation, mixed species flocking, migration, seasonal sociality, social avoidance, and dominance behaviors. Mate choice, mating system, and sexual selection are put in a new light when examined in terms of disease transmission. It is concluded that pathogen avoidance is a more powerful selective force than has heretofore been recognized.

  8. Joint Support and Efficient Offshore Investment: Market and Transmission Connection Barriers and Solutions

    DEFF Research Database (Denmark)

    Schröder, Sascha Thorsten; Kitzing, Lena; Klinge Jacobsen, Henrik

    2012-01-01

    Different support schemes are applied for the promotion of renewable energy sources in EU Member States. Current EU legislation opens opportunities for international cooperation to achieve national renewable targets more efficiently, either by statistical transfers, joint projects or joint support....... Two case studies on the regulatory combinations of joint projects financed under tendering and tradable green certificates as a joint support scheme are contrasted, addressing main barriers and possible solutions. Joint projects are an interesting option in the midterm, whereas joint support schemes...

  9. Transmission through a potential barrier in Luttinger liquids with a topological spin gap

    Science.gov (United States)

    Kainaris, Nikolaos; Carr, Sam T.; Mirlin, Alexander D.

    2018-03-01

    We study theoretically the transport of the one-dimensional single-channel interacting electron gas through a strong potential barrier in the parameter regime where the spin sector of the low-energy theory is gapped by interaction (Luther-Emery liquid). There are two distinct phases of this nature, of which one is of particular interest as it exhibits nontrivial interaction-induced topological properties. Focusing on this phase and using bosonization and an expansion in the tunneling strength we calculate the conductance through the barrier as a function of the temperature as well as the local density of states (LDOS) at the barrier. Our main result concerns the mechanism of bound-state-mediated tunneling. The characteristic feature of the topological phase is the emergence of protected zero-energy bound states with fractional spin located at the impurity position. By flipping this fractional spin, single electrons can tunnel across the impurity even though the bulk spectrum for spin excitations is gapped. This results in a finite LDOS below the bulk gap and in a nonmonotonic behavior of the conductance. The system represents an important physical example of an interacting symmetry-protected topological phase, which combines features of a topological spin insulator and a topological charge metal, in which the topology can be probed by measuring transport properties.

  10. Performance of intact and partially degraded concrete barriers in limiting mass transport

    International Nuclear Information System (INIS)

    Walton, J.C.

    1992-06-01

    Mass transport through concrete barriers and release rate from concrete vaults are quantitatively evaluated. The thorny issue of appropriate diffusion coefficients for use in performance assessment calculations is covered, with no ultimate solution found. Release from monolithic concrete vaults composed of concrete waste forms is estimated with a semi-analytical solution. A parametric study illustrates the importance of different parameters on release. A second situation of importance is the role of a concrete shell or vault placed around typical waste forms in limiting mass transport. In both situations, the primary factor controlling concrete performance is cracks. The implications of leaching behavior on likely groundwater concentrations is examined. Frequently, lower groundwater concentrations can be expected in the absence of engineered covers that reduce infiltration

  11. Risk Factors for HIV Transmission and Barriers to HIV Disclosure: Metropolitan Atlanta Youth Perspectives

    OpenAIRE

    Camacho-Gonzalez, Andres F.; Wallins, Amy; Toledo, Lauren; Murray, Ashley; Gaul, Zaneta; Sutton, Madeline Y.; Gillespie, Scott; Leong, Traci; Graves, Chanda; Chakraborty, Rana

    2016-01-01

    Youth carry the highest incidence of HIV infection in the United States. Understanding adolescent and young adult (AYA) perspectives on HIV transmission risk is important for targeted HIV prevention. We conducted a mixed methods study with HIV-infected and uninfected youth, ages 18–24 years, from Atlanta, GA. We provided self-administered surveys to HIV-infected and HIV-uninfected AYAs to identify risk factors for HIV acquisition. By means of computer-assisted thematic analyses, we examined t...

  12. Exploring superluminal transmission of electromagnetic waves through dielectric barriers and causality: a pedagogical insight

    International Nuclear Information System (INIS)

    Robles, P

    2014-01-01

    A pedagogical insight into models for determining the transit time of electromagnetic waves through dielectric barriers is presented. The meaning of this time is analyzed and the issue of superluminal propagation (propagation with a velocity higher than light velocity) is discussed in relation to the principle of causality. These analyses are illustrated with examples and comparison of results obtained with the models presented here. This paper is addressed to postgraduate physics students in the their early studies who have acquired a suitable grounding in classical electrodynamics. The main objective is to motivate these students to research these subjects further. (paper)

  13. Dose equivalent rate constants and barrier transmission data for nuclear medicine facility dose calculations and shielding design.

    Science.gov (United States)

    Kusano, Maggie; Caldwell, Curtis B

    2014-07-01

    A primary goal of nuclear medicine facility design is to keep public and worker radiation doses As Low As Reasonably Achievable (ALARA). To estimate dose and shielding requirements, one needs to know both the dose equivalent rate constants for soft tissue and barrier transmission factors (TFs) for all radionuclides of interest. Dose equivalent rate constants are most commonly calculated using published air kerma or exposure rate constants, while transmission factors are most commonly calculated using published tenth-value layers (TVLs). Values can be calculated more accurately using the radionuclide's photon emission spectrum and the physical properties of lead, concrete, and/or tissue at these energies. These calculations may be non-trivial due to the polyenergetic nature of the radionuclides used in nuclear medicine. In this paper, the effects of dose equivalent rate constant and transmission factor on nuclear medicine dose and shielding calculations are investigated, and new values based on up-to-date nuclear data and thresholds specific to nuclear medicine are proposed. To facilitate practical use, transmission curves were fitted to the three-parameter Archer equation. Finally, the results of this work were applied to the design of a sample nuclear medicine facility and compared to doses calculated using common methods to investigate the effects of these values on dose estimates and shielding decisions. Dose equivalent rate constants generally agreed well with those derived from the literature with the exception of those from NCRP 124. Depending on the situation, Archer fit TFs could be significantly more accurate than TVL-based TFs. These results were reflected in the sample shielding problem, with unshielded dose estimates agreeing well, with the exception of those based on NCRP 124, and Archer fit TFs providing a more accurate alternative to TVL TFs and a simpler alternative to full spectral-based calculations. The data provided by this paper should assist

  14. Language Barriers and their impact of Provision of Care to patients with limited English Proficiency: Nurses Perspective.

    Science.gov (United States)

    Ali, Parveen Azam; Watson, Roger

    2017-11-30

    The aim of this study was to explore nurses' perspectives of language barriers and their impact on the provision of care to patients with limited English proficiency from diverse linguistic background. A qualitative descriptive approach was used. Using individual interviews and focus group discussions, data were collected from 59 nurses working in tertiary care hospitals in England. A thematic analysis was used to analyse the data. Three themes: 'multi-ethnicities and language barriers'; 'the impact of language barriers'; and 'communicating via interpreters', were identified. Communication was identified as the most important aspect of care provision and an essential component of a nurse's professional role regardless of the clinical area or speciality. Language barriers were identified as the biggest obstacles in providing adequate, appropriate, effective and timely care to patients with limited English proficiency. Use of professional interpreters was considered useful; however, the limitations associated with use of interpretation service, including arrangement difficulties, availability and accessibility of interpreters, convenience, confidentiality and privacy related issues and impact on the patient's comfort were mentioned. Language barriers, in any country or setting, can negatively affect nurses' ability to communicate effectively with their patients and thereby have a negative impact on the provision of appropriate, timely, safe and effective care to meet patient's needs. An understanding of language barriers can help nurses find appropriate strategies to overcome such barriers and, consequently, enhance the provision of effective care to patients affected by language barriers in any clinical setting in any health care system. The findings of the study has international relevance as language barriers affect health care provision in any country or setting. This article is protected by copyright. All rights reserved. This article is protected by copyright

  15. 76 FR 12730 - Notice of Issuance of Federal Operating Permit to Great Lakes Gas Transmission Limited Partnership

    Science.gov (United States)

    2011-03-08

    ...), Chicago, Illinois 60604. FOR FURTHER INFORMATION CONTACT: Genevieve Damico, Environmental Engineer, EPA... ENVIRONMENTAL PROTECTION AGENCY [MN91; FRL-9276-5] Notice of Issuance of Federal Operating Permit to Great Lakes Gas Transmission Limited Partnership AGENCY: Environmental Protection Agency (EPA...

  16. Language barriers to prescriptions for patients with limited English proficiency: a survey of pharmacies.

    Science.gov (United States)

    Bradshaw, Michael; Tomany-Korman, Sandra; Flores, Glenn

    2007-08-01

    Twenty-three million Americans have limited English proficiency. Language barriers can have major adverse consequences in health care, but little is known about whether pharmacies provide adequate care to patients with limited English proficiency. We sought to evaluate pharmacies' ability to provide non-English-language prescription labels, information packets, and verbal communication, and assess pharmacies' satisfaction with communication with patients who have limited English proficiency. We used a cross-sectional, mixed-methods survey of Milwaukee County, Wisconsin, pharmacies. Survey questions addressed sociodemographic and language-service characteristics of pharmacies. A pharmacist or technician at each pharmacy was asked 45 questions by telephone, fax, or mail. The main outcome measures were the ability of pharmacies to provide non-English-language prescription labels, information packets, and verbal communication; and pharmacy satisfaction with communication with patients who have limited English proficiency. Of 175 pharmacies, 73% responded. Forty-seven percent of the pharmacies never/only sometimes can print non-English-language prescription labels, 54% never/only sometimes can prepare non-English-language information packets, and 64% never/only sometimes can verbally communicate in non-English languages. Eleven percent use patients' family members/friends to interpret. Only 55% were satisfied with their communication with patients who have limited English proficiency. In multivariate analyses, community pharmacies had significantly lower odds of being able to verbally communicate in non-English languages, whereas pharmacies using telephone interpreting services had significantly higher odds. Pharmacies' suggestions for improving patient communication included continuing education, producing a chain-wide list of resources, hiring bilingual staff, using telephone interpreters, analyzing translation quality/accuracy of labels and information packets, and

  17. Barriers to control syphilis and HIV vertical transmission in the health care system in the city of Sao Paulo

    Directory of Open Access Journals (Sweden)

    Valdete Maria Ramos

    2014-12-01

    Full Text Available OBJECTIVE: The objective of this study was to identify possible barriers to control vertical transmission of syphilis and HIV through the analysis of the orientation process of pregnant women from prenatal care to the obstetric center at an university hospital in Sao Paulo (Reference and their return (with their exposed babies for follow-up after hospital discharge (counter-reference. METHODS: It is a retrospective cross-sectional study including interviews with healthcare personnel. Pregnant women with syphilis and/or HIV-infection admitted for labor or miscarriage were identified from August 2006 to August 2007. Routine care for mothers and babies were analyzed. RESULTS: 56 pregnant women were identified: 43 were HIV-infected, 11 had syphilis and two were coinfected (syphilis/HIV; 22 health care professionals were interviewed. Prenatal care was identified in 91.1% of these women: 7/11 (63.6% with syphilis; 44/45 (97.8% HIV-infected or coinfected. The reference for delivery was satisfactory for 57.7% of the syphilis-infected women and 97.7% of the HIV-infected ones. The counter-reference was satisfactory for all babies and mothers at hospital discharge, besides the non-adherence to this recommendation. Interviews with health care professionals showed there are better routines for assisting and following-up pregnant women, puerperal women and HIV-infected or exposed babies than for those infected with syphilis. The epidemiological report and surveillance system are also better for HIV-infected patients. CONCLUSION: The difficulties in the reference and counter-reference system of these women and their babies are evident barriers to control the vertical transmission of these infectious diseases.

  18. Barriers to control syphilis and HIV vertical transmission in the health care system in the city of Sao Paulo.

    Science.gov (United States)

    Ramos, Valdete Maria; Figueiredo, Elisabeth Niglio de; Succi, Regina Célia de Menezes

    2014-12-01

    The objective of this study was to identify possible barriers to control vertical transmission of syphilis and HIV through the analysis of the orientation process of pregnant women from prenatal care to the obstetric center at an university hospital in Sao Paulo (Reference) and their return (with their exposed babies) for follow-up after hospital discharge (counter-reference). It is a retrospective cross-sectional study including interviews with healthcare personnel. Pregnant women with syphilis and/or HIV-infection admitted for labor or miscarriage were identified from August 2006 to August 2007. Routine care for mothers and babies were analyzed. 56 pregnant women were identified: 43 were HIV-infected, 11 had syphilis and two were coinfected (syphilis/HIV); 22 health care professionals were interviewed. Prenatal care was identified in 91.1% of these women: 7/11 (63.6%) with syphilis; 44/45 (97.8%) HIV-infected or coinfected. The reference for delivery was satisfactory for 57.7% of the syphilis-infected women and 97.7% of the HIV-infected ones. The counter-reference was satisfactory for all babies and mothers at hospital discharge, besides the non-adherence to this recommendation. Interviews with health care professionals showed there are better routines for assisting and following-up pregnant women, puerperal women and HIV-infected or exposed babies than for those infected with syphilis. The epidemiological report and surveillance system are also better for HIV-infected patients. The difficulties in the reference and counter-reference system of these women and their babies are evident barriers to control the vertical transmission of these infectious diseases.

  19. Limited English proficient HMO enrollees remain vulnerable to communication barriers despite language assistance regulations.

    Science.gov (United States)

    Hadler, Max W; Chen, Xiao; Gonzalez, Erik; Roby, Dylan H

    2013-02-01

    HMO enrollees with limited English proficiency, and particularly those in poorer health, face communication barriers despite language assistance regulations. More than 1.3 million California HMO enrollees ages 18 to 64 do not speak English well enough to communicate with medical providers and may experience reduced access to high-quality health care if they do not receive appropriate language assistance services. Based on analysis of the 2007 and 2009 California Health Interview Surveys (CHIS), commercial HMO enrollees with limited English proficiency (LEP) in poorer health are more likely to have difficulty understanding their doctors, placing this already vulnerable population at even greater risk. The analysis also uses CHIS to examine the potential impact of health plan monitoring starting in 2009 (due to a 2003 amendment to the Knox-Keene Health Care Services Act) requiring health plans to provide free qualified interpretation and translation services to HMO enrollees. The authors recommend that California's health plans continue to incorporate trained interpreters into their contracted networks and delivery systems, paying special attention to enrollees in poorer health. The results may serve as a planning tool for health plans, providing a detailed snapshot of enrollee characteristics that will help design effective programs now and prepare for a likely increase in insured LEP populations in the future, as full implementation of the Affordable Care Act takes place over the next decade.

  20. Low irradiance background limited type-II superlattice MWIR M-barrier imager.

    Science.gov (United States)

    Huang, Edward Kwei-wei; Pour, Siamak Abdollahi; Hoang, Minh-Anh; Haddadi, Abbas; Razeghi, Manijeh; Tidrow, Meimei Z

    2012-06-01

    We report a type-II superlattice mid-wave infrared 320×256 imager at 81 K with the M-barrier design that achieved background limited performance (BLIP) and ∼99% operability. The 280 K blackbody's photon irradiance was limited by an aperture and a band-pass filter from 3.6 μm to 3.8 μm resulting in a total flux of ∼5×10(12) ph.cm(-2).s(-1). Under these low-light conditions, and consequently the use of a 13.5 ms integration time, the imager was observed to be BLIP thanks to a ∼5 pA dark current from the 27 μm wide pixels. The total noise was dominated by the photon flux and read-out circuit which gave the imager a noise equivalent input of ∼5×10(10) ph.cm(-2).s(-1) and temperature sensitivity of 9 mK with F/2.3 optics. Excellent imagery obtained using a 1-point correction alludes to the array's uniform responsivity.

  1. Evaluation of five strategies to limit the impact of fouling in permeable reactive barriers

    International Nuclear Information System (INIS)

    Li Lin; Benson, Craig H.

    2010-01-01

    Ground water flow and geochemical reactive transport models were used to assess the effectiveness of five strategies used to limit fouling and to enhance the long-term hydraulic behavior of continuous-wall permeable reactive barriers (PRBs) employing granular zero valent iron (ZVI). The flow model accounted for geological heterogeneity and the reactive transport model included a geochemical algorithm for simulating iron corrosion and mineral precipitation reactions that have been observed in ZVI PRBs. The five strategies that were evaluated are pea gravel equalization zones, a sacrificial pre-treatment zone, pH adjustment, large ZVI particles, and mechanical treatment. Results of simulations show that installation of pea gravel equalization zones results in flow equalization and a more uniform distribution of residence times within the PRB. Residence times within the PRB are less affected by mineral precipitation when a pre-treatment zone is employed. pH adjustment limits the total amount of hydroxide ions in ground water to reduce porosity reduction and to retain larger residence times. Larger ZVI particles reduce porosity reduction as a result of the smaller iron surface area for iron corrosion, and retain longer residence time. Mechanical treatment redistributes the porosity uniformly throughout the PRB over time, which is effective in maintaining residence time.

  2. Barriers to men's participation in antenatal and prevention of mother-to-child HIV transmission care in Cameroon, Africa.

    Science.gov (United States)

    Nkuoh, Godlove N; Meyer, Dorothy J; Tih, Pius M; Nkfusai, Joseph

    2010-01-01

    Men's role in HIV prevention is pivotal to changing the course of the epidemic. When men participate in Prevention of Mother-to-Child Transmission (PMTCT) programs, their knowledge of HIV increases, their behavior becomes supportive, and their receptiveness to HIV testing increases. In Cameroon, Africa, multiple efforts have been implemented that encourage men to "follow" their wives to obstetric/PMTCT care and to undergo HIV testing. However, only 18% of men have participated in this care. As a quality improvement initiative, a survey was administered to identify men's knowledge and attitudes regarding antenatal care (ANC), PMTCT, and HIV. The survey consisted of a questionnaire with an emphasis on identifying barriers to men's participation in PMTCT programs and obtaining HIV testing. A convenience sampling method was used, and no participant identifying information was collected. Men's participation in ANC/PMTCT is affected by sociocultural barriers centered in tribal beliefs and traditional gender roles. The barriers identified included the belief that pregnancy is a "woman's affair"; the belief that a man's role is primarily to provide financial support for the woman's care; the man's perception that he will be viewed as jealous by the community if he comes to clinic with his pregnant wife; and cultural gender-based patterns of communication. Most men consider accompanying their wife to ANC/PMTCT a good practice. Yet fewer men actually do this, because they feel that the provision of finance for ANC registration and delivery fees is their most important role in supporting their wife's pregnancy. Health care workers should encourage individuals and community leaders to build upon the traditional value of financial responsibility, expanding a man's involvement to include supportive social roles in obstetric care, PMTCT, and HIV testing. Copyright 2010 American College of Nurse-Midwives. Published by Elsevier Inc. All rights reserved.

  3. Limited Transmission Potential of Takeda's Tetravalent Dengue Vaccine Candidate byAedes albopictus.

    Science.gov (United States)

    Dietrich, Elizabeth A; Ong, Yee Tsuey; Stovall, Janae L; Dean, Hansi; Huang, Claire Y-H

    2017-11-01

    Recombinant live-attenuated chimeric tetravalent dengue vaccine viruses, TDV-1, -2, -3, and -4, contain the premembrane and envelope genes of dengue virus serotypes 1-4 in the replicative background of the attenuated dengue virus type-2 (DENV-2) PDK-53 vaccine strain. Previous results have shown that these recombinant vaccine viruses demonstrate limited infection and dissemination in Aedes aegypti and are unlikely to be transmitted by the primary mosquito vector of DENVs. In this report, we expand this analysis by assessing vector competence of all four serotypes of the TDV virus in Aedes albopictus , the secondary mosquito vector of DENVs. Our results indicate that these vaccine viruses demonstrate incompetence or defective infection and dissemination in these mosquitoes and will likely not be transmissible.

  4. Optimizing real power loss and voltage stability limit of a large transmission network using firefly algorithm

    Directory of Open Access Journals (Sweden)

    P. Balachennaiah

    2016-06-01

    Full Text Available This paper proposes a Firefly algorithm based technique to optimize the control variables for simultaneous optimization of real power loss and voltage stability limit of the transmission system. Mathematically, this issue can be formulated as nonlinear equality and inequality constrained optimization problem with an objective function integrating both real power loss and voltage stability limit. Transformers taps, unified power flow controller and its parameters have been included as control variables in the problem formulation. The effectiveness of the proposed algorithm has been tested on New England 39-bus system. Simulation results obtained with the proposed algorithm are compared with the real coded genetic algorithm for single objective of real power loss minimization and multi-objective of real power loss minimization and voltage stability limit maximization. Also, a classical optimization method known as interior point successive linear programming technique is considered here to compare the results of firefly algorithm for single objective of real power loss minimization. Simulation results confirm the potentiality of the proposed algorithm in solving optimization problems.

  5. Linear versus non-linear structural information limit in high-resolution transmission electron microscopy

    International Nuclear Information System (INIS)

    Van Aert, S.; Chen, J.H.; Van Dyck, D.

    2010-01-01

    A widely used performance criterion in high-resolution transmission electron microscopy (HRTEM) is the information limit. It corresponds to the inverse of the maximum spatial object frequency that is linearly transmitted with sufficient intensity from the exit plane of the object to the image plane and is limited due to partial temporal coherence. In practice, the information limit is often measured from a diffractogram or from Young's fringes assuming a weak phase object scattering beyond the inverse of the information limit. However, for an aberration corrected electron microscope, with an information limit in the sub-angstrom range, weak phase objects are no longer applicable since they do not scatter sufficiently in this range. Therefore, one relies on more strongly scattering objects such as crystals of heavy atoms observed along a low index zone axis. In that case, dynamical scattering becomes important such that the non-linear and linear interaction may be equally important. The non-linear interaction may then set the experimental cut-off frequency observed in a diffractogram. The goal of this paper is to quantify both the linear and the non-linear information transfer in terms of closed form analytical expressions. Whereas the cut-off frequency set by the linear transfer can be directly related with the attainable resolution, information from the non-linear transfer can only be extracted using quantitative, model-based methods. In contrast to the historic definition of the information limit depending on microscope parameters only, the expressions derived in this paper explicitly incorporate their dependence on the structure parameters as well. In order to emphasize this dependence and to distinguish from the usual information limit, the expressions derived for the inverse cut-off frequencies will be referred to as the linear and non-linear structural information limit. The present findings confirm the well-known result that partial temporal coherence has

  6. Barriers to Combined-Modality Therapy for Limited-Stage Small-Cell Lung Cancer.

    Science.gov (United States)

    Pezzi, Todd A; Schwartz, David L; Mohamed, Abdallah S R; Welsh, James W; Komaki, Ritsuko U; Hahn, Stephen M; Sepesi, Boris; Pezzi, Christopher M; Fuller, Clifton D; Chun, Stephen G

    2018-01-04

    Combined-modality therapy with chemotherapy and radiation therapy plays a crucial role in the upfront treatment of patients with limited-stage small-cell lung cancer (SCLC), but there may be barriers to utilization in the United States. To estimate utilization rates and factors associated with chemotherapy and radiation therapy delivery for limited-stage SCLC using the National Cancer Database. Analysis of initial management of all limited-stage SCLC cases from 2004 through 2013 in the National Cancer Database. Utilization rates of chemotherapy and radiation therapy at time of initial treatment. Multivariable analysis identified independent clinical and socioeconomic factors associated with utilization and overall survival. A total of 70 247 cases met inclusion criteria (55.3% female; median age, 68 y [range, 19-90 y]). Initial treatment was 55.5% chemotherapy and radiation therapy, 20.5% chemotherapy alone, 3.5% radiation therapy alone, and 20.0% neither (0.5% not reported). Median survival was 18.2 (95% CI, 17.9-18.4), 10.5 (95% CI, 10.3-10.7), 8.3 (95% CI, 7.7-8.8), and 3.7 (95% CI, 3.5-3.8) months, respectively. Being uninsured was associated with a lower likelihood of both chemotherapy (odds ratio [OR], 0.65; 95% CI, 0.56-0.75; P therapy (OR, 0.75; 95% CI, 0.67-0.85; P therapy delivery. Lack of health insurance (HR, 1.19; 95% CI, 1.13-1.26; P therapy (HR, 0.62; 95% CI, 0.60-0.63; P therapy or chemotherapy as part of initial treatment for limited-stage SCLC, which, in turn, was associated with poor survival. Lack of radiation therapy delivery was uniquely associated with government insurance coverage, suggesting a need for targeted access improvement in this population. Additional work will be necessary to conclusively define exact population patterns, specific treatment deficiencies, and causative factors leading to heterogeneous care delivery.

  7. Multiple Schottky Barrier-Limited Field-Effect Transistors on a Single Silicon Nanowire with an Intrinsic Doping Gradient.

    Science.gov (United States)

    Barreda, Jorge L; Keiper, Timothy D; Zhang, Mei; Xiong, Peng

    2017-04-05

    In comparison to conventional (channel-limited) field-effect transistors (FETs), Schottky barrier-limited FETs possess some unique characteristics which make them attractive candidates for some electronic and sensing applications. Consequently, modulation of the nano Schottky barrier at a metal-semiconductor interface promises higher performance for chemical and biomolecular sensor applications when compared to conventional FETs with ohmic contacts. However, the fabrication and optimization of devices with a combination of ideal ohmic and Schottky contacts as the source and drain, respectively, present many challenges. We address this issue by utilizing Si nanowires (NWs) synthesized by a chemical vapor deposition process which yields a pronounced doping gradient along the length of the NWs. Devices with a series of metal contacts on a single Si NW are fabricated in a single lithography and metallization process. The graded doping profile of the NW is manifested in monotonic increases in the channel and junction resistances and variation of the nature of the contacts from ohmic to Schottky of increasing effective barrier height along the NW. Hence multiple single Schottky junction-limited FETs with extreme asymmetry and high reproducibility are obtained on an individual NW. A definitive correlation between increasing Schottky barrier height and enhanced gate modulation is revealed. Having access to systematically varying Schottky barrier contacts on the same NW device provides an ideal platform for identifying optimal device characteristics for sensing and electronic applications.

  8. Financial burdens and barriers to care among nonelderly adults: The role of functional limitations and chronic conditions.

    Science.gov (United States)

    Bernard, Didem; Selden, Thomas; Yeh, Susan

    2016-04-01

    People with functional limitations and chronic conditions account for the greatest resource use within the health care system. To examine financial burdens and barriers to care among nonelderly adults, focusing on the role of functional limitations and chronic conditions. High financial burden is defined as medical spending exceeding 20 percent of family income. Financial barriers are defined as delaying care/being unable to get care for financial reasons, and reporting that delaying care/going without was a big problem. Data are from the Medical Expenditure Panel Survey (2008-2012). Functional limitations are associated with increased prevalence of financial burdens. Among single adults, the frequency of high burdens is 20.3% for those with functional limitations, versus 7.8% for those without. Among those with functional limitations, those with 3 or more chronic conditions are twice as likely to have high burdens compared to those without chronic conditions (22.2% versus 11.1%, respectively). Similar patterns occur among persons in multi-person families whose members have functional limitations and chronic conditions. Having functional limitations and chronic conditions is also strongly associated with financial barriers to care: 40.2% among the uninsured, 21.9% among those with public coverage, and 13.6% among those with private group insurance were unable to get care. Functional limitations and chronic conditions are associated with increased prevalence of burdens and financial barriers in all insurance categories, with the exception that an association between functional limitations and the prevalence of burdens was not observed for public coverage. Published by Elsevier Inc.

  9. Variable speed limit strategies analysis with link transmission model on urban expressway

    Science.gov (United States)

    Li, Shubin; Cao, Danni

    2018-02-01

    The variable speed limit (VSL) is a kind of active traffic management method. Most of the strategies are used in the expressway traffic flow control in order to ensure traffic safety. However, the urban expressway system is the main artery, carrying most traffic pressure. It has similar traffic characteristics with the expressways between cities. In this paper, the improved link transmission model (LTM) combined with VSL strategies is proposed, based on the urban expressway network. The model can simulate the movement of the vehicles and the shock wave, and well balance the relationship between the amount of calculation and accuracy. Furthermore, the optimal VSL strategy can be proposed based on the simulation method. It can provide management strategies for managers. Finally, a simple example is given to illustrate the model and method. The selected indexes are the average density, the average speed and the average flow on the traffic network in the simulation. The simulation results show that the proposed model and method are feasible. The VSL strategy can effectively alleviate traffic congestion in some cases, and greatly promote the efficiency of the transportation system.

  10. European concerted action on offshore wind energy deployment: inventory and analysis of power transmission barriers in eight member states

    International Nuclear Information System (INIS)

    Woyte, Achim; Gardner, Paul; Snodin, Helen

    2007-01-01

    The European Concerted Action for Offshore Wind Energy Deployment (COD) was carried out by eight sea-bordering European Union member states, with the objective to remove not explicitly technical barriers to offshore wind energy. Within the COD, an inventory of relevant aspects affecting the grid integration of offshore wind energy on a large scale in the eight countries has been made. Collected data items for this inventory are national plans and prospects for offshore wind energy, information about the transmission system, possibilities for grid connection, aspects of the grid codes, balancing, connection and energy pricing. The comprehensive COD reports were published and presented in October 2005 during the Copenhagen Offshore wind conference. This paper provides a short description of the situation for each country. Thereafter, country-specific information is grouped based on geography and membership in a synchronous zone. Additionally, a view is developed on the desirable facilities for the trans-European exchange of power from large wind farms. Finally, we elaborate overall conclusions in order to arrive at generalized observations, recommendations for policy makers and issues that will emerge in the near future. As a general conclusion, many things need to be done on a technical level in order to integrate large amounts of offshore wind power into our power systems. However, none of these measures is technically unknown. Therefore, the feasibility of integrating large amounts of offshore wind power is mainly a question of finance and hence based on political decisions. (Author)

  11. Limited variation in vaccine candidate Plasmodium falciparum Merozoite Surface Protein-6 over multiple transmission seasons

    Directory of Open Access Journals (Sweden)

    Branch OraLee H

    2010-05-01

    Full Text Available Abstract Background Plasmodium falciparum Merozoite Surface Protein-6 (PfMSP6 is a component of the complex proteinacious coat that surrounds P. falciparum merozoites. This location, and the presence of anti-PfMSP6 antibodies in P. falciparum-exposed individuals, makes PfMSP6 a potential blood stage vaccine target. However, genetic diversity has proven to be a major hurdle for vaccines targeting other blood stage P. falciparum antigens, and few endemic field studies assessing PfMSP6 gene diversity have been conducted. This study follows PfMSP6 diversity in the Peruvian Amazon from 2003 to 2006 and is the first longitudinal assessment of PfMSP6 sequence dynamics. Methods Parasite DNA was extracted from 506 distinct P. falciparum infections spanning the transmission seasons from 2003 to 2006 as part of the Malaria Immunology and Genetics in the Amazon (MIGIA cohort study near Iquitos, Peru. PfMSP6 was amplified from each sample using a nested PCR protocol, genotyped for allele class by agarose gel electrophoresis, and sequenced to detect diversity. Allele frequencies were analysed using JMP v.8.0.1.0 and correlated with clinical and epidemiological data collected as part of the MIGIA project. Results Both PfMSP6 allele classes, K1-like and 3D7-like, were detected at the study site, confirming that both are globally distributed. Allele frequencies varied significantly between transmission seasons, with 3D7-class alleles dominating and K1-class alleles nearly disappearing in 2005 and 2006. There was a significant association between allele class and village location (p-value = 0.0008, but no statistically significant association between allele class and age, sex, or symptom status. No intra-allele class sequence diversity was detected. Conclusions Both PfMSP6 allele classes are globally distributed, and this study shows that allele frequencies can fluctuate significantly between communities separated by only a few kilometres, and over time in the

  12. Performance of intact and partially degraded concrete barriers in limiting fluid flow

    International Nuclear Information System (INIS)

    Walton, J.C.; Seitz, R.R.

    1991-07-01

    Concrete barriers will play a critical role in the long-term isolation of low-level radioactive wastes. Over time the barriers will degrade, and in many cases, the fundamental processes controlling performance of the barriers will be different for intact and degraded conditions. This document examines factors controlling fluid flow through intact and degraded concrete disposal facilities. Simplified models are presented fro predicting build up of fluid above a vault; fluid flow through and around intact vaults, through flaws in coatings/liners applied to a vault, and through cracks in a concrete vault; and the influence of different backfill materials around the outside of the vault. Example calculations are presented to illustrate the parameters and processes that influence fluid flow. 46 refs., 49 figs., 2 tabs

  13. Handling transmission limitations in the central power network; Haandtering av overfoeringsbegrensninger

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-01

    From 1996, the Norwegian and Swedish power markets were joined and a common power exchange was established. The two countries deal differently with bottlenecks (transmission obstruction) in their central networks. This report compares methods for dealing with such bottlenecks and looks at the alternatives. It emphasises the efficiency of pricing and incentives and the possibility of exercising market power under the different methods. Norway uses a method of price regions, or bottleneck tax. Prices are determined for the various price regions so as to keep the power flow below specified bounds. A surplus region is assigned a lower price than a deficit region and the bottleneck tax is the difference in price between two such price regions. The Swedish system is based on a counter purchase concept. In his offer to the spotmarket, the supplier has bound himself to provide a certain amount to the current system price regardless of network limitations. Up-regulation means that he produces more than this amount. Down-regulation means that he is paid for supplying less than he had offered to the current system price. In up- or down-regulation, compensation is given as the difference between the system price and the price on the counter purchase market. The main conclusions are: (1) Counter purchase is unsuitable as the main strategy for Norway. (2) Counter purchase may be suitable with short-lived and unpredicted bottlenecks; price regions may be suitable for long-lasting and predicted bottlenecks. Time is a central factor. (3) Present-day models for bottleneck management in Norway and Sweden do not give the optimum short-term load distribution on the network. In general, the current Norwegian system works fairly well, although it might be worthwhile to consider a system that approaches node pricing. 3 refs., 34 figs., 3 tabs.

  14. Human immunodeficiency virus-associated disruption of mucosal barriers and its role in HIV transmission and pathogenesis of HIV/AIDS disease

    Science.gov (United States)

    Tugizov, Sharof

    2016-01-01

    Abstract Oral, intestinal and genital mucosal epithelia have a barrier function to prevent paracellular penetration by viral, bacterial and other pathogens, including human immunodeficiency virus (HIV). HIV can overcome these barriers by disrupting the tight and adherens junctions of mucosal epithelia. HIV-associated disruption of epithelial junctions may also facilitate paracellular penetration and dissemination of other viral pathogens. This review focuses on possible molecular mechanisms of HIV-associated disruption of mucosal epithelial junctions and its role in HIV transmission and pathogenesis of HIV and acquired immune deficiency syndrome (AIDS). PMID:27583187

  15. The Dragons of Inaction: Psychological Barriers That Limit Climate Change Mitigation and Adaptation

    Science.gov (United States)

    Gifford, Robert

    2011-01-01

    Most people think climate change and sustainability are important problems, but too few global citizens engaged in high-greenhouse-gas-emitting behavior are engaged in enough mitigating behavior to stem the increasing flow of greenhouse gases and other environmental problems. Why is that? Structural barriers such as a climate-averse infrastructure…

  16. Designing low permeability, optical-grade silicone systems: guidelines for choosing a silicone based on transmission rates for barrier applications

    Science.gov (United States)

    Velderrain, Michelle

    2012-03-01

    Unprotected electronic components exposed to moisture from high humidity may fail due to corrosion of metal leads or other unfavorable reactions on chemically sensitive components. This is of high interest for silicones that encapsulate Light Emitting Diodes (LEDs) dies. For these applications, moisture and oxygen may react with materials, such as phosphor, used to make white LEDs for back-lighting applications and decrease or change the light output and color over time. Of the polymeric adhesives and sealants commercially available, silicones are used for their thermal stability, clarity, and comparably low modulus that provides stress relief during thermal cycling. In addition, silicones are also known to be very permeable to low molecular weight gases such as water vapor and oxygen. Recently, several types of silicones were tested for the oxygen and water vapor transmission rates, and it was found that they can have drastically different results. Silicone properties strongly affecting permeability are polymer backbone chemistry, crosslink density and fillers. Phenyl (C6H5) and trifluoropropyl (CF3CH2) groups are used to optimize the refractive index of optically clear silicones. The effect of chemical composition on the water vapor transfer rate (WVTR) and the oxygen transfer rate (OTR) at 400 C and 90% Relative Humidity was investigated on several silicones with various refractive indices and compared to polydimethylsiloxane (PDMS) with similar durometers. It was found that polymer backbone chemistry had a significant influence on the permeation rates and will assist in material selection when designing for low-permeable barriers to improve package reliability.

  17. Modeling hepatitis C virus transmission among people who inject drugs: Assumptions, limitations and future challenges.

    Science.gov (United States)

    Scott, Nick; Hellard, Margaret; McBryde, Emma Sue

    2016-01-01

    The discovery of highly effective hepatitis C virus (HCV) treatments has led to discussion of elimination and intensified interest in models of HCV transmission. In developed settings, HCV disproportionally affects people who inject drugs (PWID), and models are typically used to provide an evidence base for the effectiveness of interventions such as needle and syringe programs, opioid substitution therapy and more recently treating PWID with new generation therapies to achieve specified reductions in prevalence and / or incidence. This manuscript reviews deterministic compartmental S-I, deterministic compartmental S-I-S and network-based transmission models of HCV among PWID. We detail typical assumptions made when modeling injecting risk behavior, virus transmission, treatment and re-infection and how they correspond with available evidence and empirical data.

  18. Barriers and enablers of the prevention of mother-to-child transmission of HIV/AIDS program in China: a systematic review and policy implications.

    Science.gov (United States)

    Peng, Zhuoxin; Wang, Shengnan; Xu, Biao; Wang, Weibing

    2017-02-01

    To identify the barriers to and enablers of the prevention of mother-to-child transmission (PMTCT) of HIV program in China. A systematic review of the existing literature regarding barriers to and enablers of the implementation of the PMTCT program in China was performed. The checklist from the SURE guidelines (Supporting the Use of Research Evidence) was used to synthesize the barriers and enablers (supporting strategies) and to analyze their relationships. The HIV testing rate, vertical transmission rate, and antiretroviral treatment (ART) acceptance rate among HIV-infected women and their infants was also extracted from the included studies to assess the effectiveness of the enablers. Initially 794 publications were identified, and ultimately 14 articles were included. Eighteen types of barrier and nine types of supportive strategy were identified, mainly at the level of social and political issues, healthcare recipients, healthcare providers, and the healthcare system. Based on government-oriented multi-sector cooperation, enablers in China have included community-hospital-family promotion, comprehensive financial support for service recipients, free HIV testing at marriage registration, the opt-out model, and the one-to-one service model. Experience in China suggests that the government's role in coordination and the acceptability and accessibility of the service should be the primary concerns in regard to the PMTCT project. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  19. A comprehensive review of the barriers and promoters health workers experience in delivering prevention of vertical transmission of HIV services in sub-Saharan Africa.

    Science.gov (United States)

    Schuster, Roseanne C; McMahon, Devon E; Young, Sera L

    2016-01-01

    Despite significant biomedical and policy advances, 199,000 infants and young children in sub-Saharan Africa (SSA) became infected with HIV in 2013, indicating challenges to implementation of these advances. To understand the nature of these challenges, we sought to (1) characterize the barriers and facilitators that health workers encountered delivering prevention of vertical transmission of HIV (PVT) services in SSA and (2) evaluate the use of theory to guide PVT service delivery. The PubMed and CINAHL databases were searched using keywords barriers, facilitators, HIV, prevention of vertical transmission of HIV, health workers, and their synonyms to identify relevant studies. Barriers and facilitators were coded at ecological levels according to the Determinants of Performance framework. Factors in this framework were then classified as affecting motivation, opportunity, or ability, per the Motivation-Opportunity-Ability (MOA) framework in order to evaluate domains of health worker performance within each ecological level. We found that the most frequently reported challenges occurred within the health facility level and spanned all three MOA domains. Barriers reported in 30% or more of studies from most proximal to distal included those affecting health worker motivation (stress, burnout, depression), patient opportunity (stigma), work opportunity (poor referral systems), health facility opportunity (overburdened workload, lack of supplies), and health facility ability (inadequate PVT training, inconsistent breastfeeding messages). Facilitators were reported in lower frequencies than barriers and tended to be resolutions to challenges (e.g., quality supervision, consistent supplies) or responses to an intervention (e.g., record systems and infrastructure improvements). The majority of studies did not use theory to guide study design or implementation. Interventions addressing health workers' multiple ecological levels of interactions, particularly the health

  20. Limited variation of the 5'cis-control region of the transmission ...

    African Journals Online (AJOL)

    Genetic recombination during sexual reproduction within Plasmodium sp. contributes to parasite diversity and altered gene expression of certain surface markers. The pfs25 gene involved in the upset of gametocytogenesis is a candidate antigen in transmission blocking vaccine. This study investigated the polymorphism of ...

  1. A novel power efficient location-based cooperative routing with transmission power-upper-limit for wireless sensor networks.

    Science.gov (United States)

    Shi, Juanfei; Calveras, Anna; Cheng, Ye; Liu, Kai

    2013-05-15

    The extensive usage of wireless sensor networks (WSNs) has led to the development of many power- and energy-efficient routing protocols. Cooperative routing in WSNs can improve performance in these types of networks. In this paper we discuss the existing proposals and we propose a routing algorithm for wireless sensor networks called Power Efficient Location-based Cooperative Routing with Transmission Power-upper-limit (PELCR-TP). The algorithm is based on the principle of minimum link power and aims to take advantage of nodes cooperation to make the link work well in WSNs with a low transmission power. In the proposed scheme, with a determined transmission power upper limit, nodes find the most appropriate next nodes and single-relay nodes with the proposed algorithm. Moreover, this proposal subtly avoids non-working nodes, because we add a Bad nodes Avoidance Strategy (BAS). Simulation results show that the proposed algorithm with BAS can significantly improve the performance in reducing the overall link power, enhancing the transmission success rate and decreasing the retransmission rate.

  2. Limitations in the use of Barrier Buckets in a Beta Beam Decay Ring

    CERN Document Server

    Hansen, C; Fernandez Martinez, E F

    2010-01-01

    Beta Beam, the concept of letting accelerated radioactive ions generate a pure and intense (anti-) neutrino beam by beta decay, is the base of one of the pro- posed next generation neutrino oscillation facilities, necessary for a complete study of the neutrino oscillation parameter space. The first CERN based sce- nario, using 18Ne and 6He as !e and ¯!e emitters respectively, has shown a shortfall in 18Ne production. We have now entered the era of the studies of an alternative CERN based baseline. This alternative investigates how the ions 8B and 8Li can be produced in high quantities in a ”Production Ring”, accel- erated and then accumulated in a ”Decay Ring”. The idea of an alternative RF scheme for the Decay Ring, to use RF barriers to collect all ions in one ”Bar- rier Bucket”, has been tested. Longitudinal phase space simulations show that with the Barrier Bucket method it is unfeasible to optimize between ion inten- sity in the bucket and the duty cycle the bucket occupy. Therefore the prio...

  3. Contact heterogeneity, rather than transmission efficiency, limits the emergence and spread of canine influenza virus.

    Directory of Open Access Journals (Sweden)

    Benjamin D Dalziel

    2014-10-01

    Full Text Available Host-range shifts in influenza virus are a major risk factor for pandemics. A key question in the study of emerging zoonoses is how the evolution of transmission efficiency interacts with heterogeneity in contact patterns in the new host species, as this interplay influences disease dynamics and prospects for control. Here we use a synergistic mixture of models and data to tease apart the evolutionary and demographic processes controlling a host-range shift in equine H3N8-derived canine influenza virus (CIV. CIV has experienced 15 years of continuous transfer among dogs in the United States, but maintains a patchy distribution, characterized by sporadic short-lived outbreaks coupled with endemic hotspots in large animal shelters. We show that CIV has a high reproductive potential in these facilities (mean R(0 = 3.9 and that these hotspots act as refugia from the sparsely connected majority of the dog population. Intriguingly, CIV has evolved a transmission efficiency that closely matches the minimum required to persist in these refugia, leaving it poised on the extinction/invasion threshold of the host contact network. Corresponding phylogenetic analyses show strong geographic clustering in three US regions, and that the effective reproductive number of the virus (R(e in the general dog population is close to 1.0. Our results highlight the critical role of host contact structure in CIV dynamics, and show how host contact networks could shape the evolution of pathogen transmission efficiency. Importantly, efficient control measures could eradicate the virus, in turn minimizing the risk of future sustained transmission among companion dogs that could represent a potential new axis to the human-animal interface for influenza.

  4. Nonlinear dynamics of a friction-limited drive: Application to a chain continuously variable transmission (CVT) system

    Science.gov (United States)

    Srivastava, Nilabh; Haque, Imtiaz

    2009-03-01

    Over the past two decades, extensive research has been conducted on developing vehicle transmissions that meet the goals of reduced exhaust emissions and increased vehicle efficiency. A continuously variable transmission is an emerging automotive transmission technology that offers a continuum of gear ratios between desired limits. A chain CVT is a friction-limited drive whose dynamic performance and torque capacity rely significantly on the friction characteristic of the contact patch between the chain and the pulley. Although a CVT helps to maximize the vehicle fuel economy, its complete potential has not been accomplished in a mass-production vehicle. The present research focuses on developing models to analyze friction-induced nonlinear dynamics of a chain CVT drive and identify possible mechanisms that cause degradation of the overall dynamic performance by inducing chaos and self-sustained vibrations in the system. Two different mathematical models of friction, which characterize different operating or loading conditions, are embedded into a detailed planar multibody model of chain CVT in order to capture the various friction-induced effects in the system. Tools such as stick-slip oscillator dynamics, Lyapunov exponents, phase-space reconstruction, and recurrence plotting are incorporated to characterize the nonlinear dynamics of such a friction-limited system. The mathematical models, the computational scheme, and the results corresponding to different loading scenarios are discussed. The results discuss the influence of friction characteristics on the nonlinear dynamics and torque transmitting capacity of a chain CVT drive.

  5. Beating the classical limits of information transmission using a quantum decoder

    Science.gov (United States)

    Chapman, Robert J.; Karim, Akib; Huang, Zixin; Flammia, Steven T.; Tomamichel, Marco; Peruzzo, Alberto

    2018-01-01

    Encoding schemes and error-correcting codes are widely used in information technology to improve the reliability of data transmission over real-world communication channels. Quantum information protocols can further enhance the performance in data transmission by encoding a message in quantum states; however, most proposals to date have focused on the regime of a large number of uses of the noisy channel, which is unfeasible with current quantum technology. We experimentally demonstrate quantum enhanced communication over an amplitude damping noisy channel with only two uses of the channel per bit and a single entangling gate at the decoder. By simulating the channel using a photonic interferometric setup, we experimentally increase the reliability of transmitting a data bit by greater than 20 % for a certain damping range over classically sending the message twice. We show how our methodology can be extended to larger systems by simulating the transmission of a single bit with up to eight uses of the channel and a two-bit message with three uses of the channel, predicting a quantum enhancement in all cases.

  6. Limited evidence of HCV transmission in stable heterosexual couples from Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Márcia Bessa

    Full Text Available HCV infected patients frequently ask their physician about the risk of transmission to their partners. Although it is easy to answer that the risk does exist, it is difficult to quantify. We studied the transmission of HCV infection in stable heterosexual couples: anti-HCV positive patients in hemodialytic therapy and their partners. Thirty-four couples were tested by third generation ELISA and RIBA. Blood samples of anti-HCV positive patients were evaluated by RT-PCR and detected sequences were genotyped by restriction fragment length polymorphism. Concordance of infection was observed in only one couple in which both subjects were in dialytic therapy. One other partner had two positive ELISA tests and an indeterminate RIBA, with negative RT-PCR, which may suggest a false positive or a previous resolved infection. Either sexual relations, sharing of personal items and history of parenteral exposure (hemodialysis, blood transfusion could explain transmission in the only couple with concordant infection. We observed, in accordance with previous reports, that this risk is minimal or negligible in stable heterosexual couples.

  7. Barriers to the Flow of Technical Information: Limitation Statements - Legal Basis.

    Science.gov (United States)

    Downie, Currie S.

    The new "Freedom of Information Act" and the more important reasons for limitations on the flow of information are discussed. The legal basis for these limitations can be found in the almost 100 statutory provisions which prohibit, exempt, or otherwise protect certain types of information from disclosure. The Export Control Acts of the Department…

  8. Vasoinhibins regulate the inner and outer blood-retinal barrier and limit retinal oxidative stress

    Directory of Open Access Journals (Sweden)

    David eArredondo Zamarripa

    2014-10-01

    Full Text Available Vasoinhibins are prolactin fragments present in the retina, where they have been shown to prevent the hypervasopermeability associated with diabetes. Enhanced bradykinin (BK production contributes to the increased transport through the blood-retina barrier (BRB in diabetes. Here, we studied if vasoinhibins regulate BRB permeability by targeting the vascular endothelium and retinal pigment epithelium (RPE components of this barrier. Intravitreal injection of BK in male rats increased BRB permeability. Vasoinhibins prevented this effect, as did the B2 receptor antagonist Hoe-140. BK induced a transient decrease in mouse retinal and brain capillary endothelial monolayer resistance that was blocked by vasoinhibins. Both vasoinhibins and the nitric oxide (NO synthase inhibitor L-NAME, but not the antioxidant N-acetyl cysteine (NAC, blocked the transient decrease in bovine umbilical vein endothelial cell (BUVEC monolayer resistance induced by BK; this block was reversed by the NO donor DETANONOate. Vasoinhibins also prevented the BK-induced actin cytoskeleton redistribution, as did L-NAME. BK transiently decreased human RPE (ARPE-19 cell monolayer resistance, and this effect was blocked by vasoinhibins, L-NAME, and NAC. DETANONOate reverted the blocking effect of vasoinhibins. Similar to BK, the radical initiator Luperox induced a reduction in ARPE-19 cell monolayer resistance, which was prevented by vasoinhibins. These effects on RPE resistance coincided with actin cytoskeleton redistribution. Intravitreal injection of vasoinhibins reduced the levels of reactive oxygen species (ROS in retinas of streptozotocin-induced diabetic rats, particularly in the RPE and capillary-containing layers. Thus, vasoinhibins reduce BRB permeability by targeting both its main inner and outer components through NO- and ROS-dependent pathways, offering potential treatment strategies against diabetic retinopathies.

  9. Immune Evasion Strategies of Pathogens in Macrophages: the Potential for Limiting Pathogen Transmission.

    Science.gov (United States)

    Ren, Yuwei; Khan, Faheem Ahmed; Pandupuspitasari, Nuruliarizki Shinta; Zhang, Shujun

    2017-01-01

    Preventing pathogen transmission to a new host is of major interest to the immunologist and could benefit from a detailed investigation of pathogen immune evasion strategies. The first line of defense against pathogen invasion is provided by macrophages. When they sense pathogens, macrophages initiate signals to inflammatory and pro-inflammatory cytokines through pattern recognition receptors (PRRs) subsequently mediating phagocytosis and inflammation. The macrophage immune machinery classically includes two subsets: the activated M1 and the activated M2 that respond accordingly in diverse immune challenges. The lipid and glycogen metabolic pathways work together with the lysosome to help the mature phagosome to degrade and eliminate intracellular pathogens in macrophages. The viral evasion strategies are even more complex due to the interplay between autophagy and apoptosis. However, pathogens evolve several strategies to camouflage themselves against immune responses in order to ensure their survival, replication and transmission. These strategies include the muting of PRRs initiated inflammatory responses, attenuation of M1 and/or induction of M2 macrophages, suppression of autophago-lysosomal formation, interference with lipid and glycogen metabolism, and viral mediation of autophagy and apoptosis cross-talk to enhance viral replication. This review focuses on pathogen immune evasion methods and on the strategies used by the host against camouflaged pathogens.

  10. Downhill versus barrier-limited folding of BBL 2: mechanistic insights from kinetics of folding monitored by independent tryptophan probes.

    Science.gov (United States)

    Neuweiler, Hannes; Sharpe, Timothy D; Johnson, Christopher M; Teufel, Daniel P; Ferguson, Neil; Fersht, Alan R

    2009-04-10

    Barrier-free downhill folding has been proposed for the peripheral subunit-binding domain BBL. To date, ultrafast kinetic experiments on BBL, which are crucial for a mechanistic understanding of folding, have been hampered by the lack of good intrinsic spectroscopic probes. Here, we present a detailed kinetic characterization of three single-point tryptophan mutants of BBL that have suitable fluorescence properties for following microsecond and nanosecond folding kinetics using temperature jump fluorescence spectroscopy. Experiments were performed at pH 7, which is optimal for stability and minimizes complications that arise from the presence of an alternative native-state conformation of BBL at lower pH. We examined the dependence of rate and equilibrium constants on concentration of denaturant and found that they follow well-established laws allowing kinetic transients to be related to events in folding and compared with equilibrium data. Logarithms of rate constants versus denaturant concentration yielded plots (chevrons) that are characteristic of barrier-limited folding for all mutants investigated, including a truncated sequence that was previously used in the proposal of downhill folding. The thermodynamic quantities calculated from the rate constants were in excellent agreement with those directly determined from equilibrium denaturation based on empirical two-state equations. We found that sequence truncation of BBL as used in studies proposing downhill folding leads to a large loss in helical content and protein stability, which were exacerbated at the low pH used in those studies. The kinetics and equilibria of folding of BBL fit to conventional barrier-limited kinetics.

  11. Multilocus genotyping of human Giardia isolates suggests limited zoonotic transmission and association between assemblage B and flatulence in children.

    Directory of Open Access Journals (Sweden)

    Marianne Lebbad

    2011-08-01

    Full Text Available BACKGROUND: Giardia intestinalis is one of the most common diarrhea-related parasites in humans, where infection ranges from asymptomatic to acute or chronic disease. G. intestinalis consists of eight genetically distinct genotypes or assemblages, designated A-H, and assemblages A and B can infect humans. Giardiasis has been classified as a possible zoonotic disease but the role of animals in human disease transmission still needs to be proven. We tried to link different assemblages and sub-assemblages of G. intestinalis isolates from Swedish human patients to clinical symptoms and zoonotic transmission. METHODOLOGY/PRINCIPAL FINDINGS: Multilocus sequence-based genotyping of 207 human Giardia isolates using three gene loci: ß-giardin, glutamate dehydrogenase (gdh, and triose phosphate isomerase (tpi was combined with assemblage-specific tpi PCRs. This analysis identified 73 patients infected with assemblage A, 128 with assemblage B, and six with mixed assemblages A+B. Multilocus genotypes (MLGs were easily determined for the assemblage A isolates, and most patients with this genotype had apparently been infected through anthroponotic transmission. However, we also found evidence of limited zoonotic transmission of Giardia in Sweden, since a few domestic human infections involved the same assemblage A MLGs previously reported in Swedish cats and ruminants. Assemblage B was detected more frequently than assemblage A and it was also more common in patients with suspected treatment failure. However, a large genetic variability made determination of assemblage B MLGs problematic. Correlation between symptoms and assemblages was found only for flatulence, which was significantly more common in children less than six years of age infected with assemblage B. CONCLUSIONS/SIGNIFICANCE: This study shows that certain assemblage A subtypes are potentially zoonotic and that flatulence is connected to assemblage B infections in young children. Determination

  12. Transmission electron microscopy study for investigating high-temperature reliability of Ti10W90-based and Ta-based diffusion barriers up to 600 C

    International Nuclear Information System (INIS)

    Budhiman, Nando; Schuermann, Ulrich; Kienle, Lorenz; Jensen, Bjoern; Chemnitz, Steffen; Wagner, Bernhard

    2016-01-01

    Abstractauthoren Transmission electron microscopy (TEM) analysis, including energy dispersive X-ray (EDX) (elemental mapping, line, and point measurements) and energy filtered TEM (EFTEM) methods, is applied to investigate the high temperature reliability, especially material diffusion, of two types of diffusion barriers: titanium-tungsten-based (Ti 10 W 90 -based) and tantalum-based (Ta-based), with nickel (Ni) layer on top. Both barriers were deposited as a form of stacked layers on sili-con (Si) wafers using the physical vapor deposition (PVD) technique. TEM analysis is performed on both barriers before and after annealing (at 600 C for 24 h inside a vacuum chamber). No diffusion of material into the Si substrate as observed. Additionally, only diffusion between the Ni and adjoining Ti 10 W 90 layers, and between Ni and adjoining Ta layers in the Ti 10 W 90 -based and Ta-based barriers, respectively, are observed due to annealing. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Conservation of functional domains and limited heterogeneity of HIV-1 reverse transcriptase gene following vertical transmission

    Directory of Open Access Journals (Sweden)

    Ahmad Nafees

    2005-05-01

    Full Text Available Abstract Background The reverse transcriptase (RT enzyme of human immunodeficiency virus type 1 (HIV-1 plays a crucial role in the life cycle of the virus by converting the single stranded RNA genome into double stranded DNA that integrates into the host chromosome. In addition, RT is also responsible for the generation of mutations throughout the viral genome, including in its own sequences and is thus responsible for the generation of quasi-species in HIV-1-infected individuals. We therefore characterized the molecular properties of RT, including the conservation of functional motifs, degree of genetic diversity, and evolutionary dynamics from five mother-infant pairs following vertical transmission. Results The RT open reading frame was maintained with a frequency of 87.2% in five mother-infant pairs' sequences following vertical transmission. There was a low degree of viral heterogeneity and estimates of genetic diversity in mother-infant pairs' sequences. Both mothers and infants RT sequences were under positive selection pressure, as determined by the ratios of non-synonymous to synonymous substitutions. Phylogenetic analysis of 132 mother-infant RT sequences revealed distinct clusters for each mother-infant pair, suggesting that the epidemiologically linked mother-infant pairs were evolutionarily closer to each other as compared with epidemiologically unlinked mother-infant pairs. The functional domains of RT which are responsible for reverse transcription, DNA polymerization and RNase H activity were mostly conserved in the RT sequences analyzed in this study. Specifically, the active sites and domains required for primer binding, template binding, primer and template positioning and nucleotide recruitment were conserved in all mother-infant pairs' sequences. Conclusion The maintenance of an intact RT open reading frame, conservation of functional domains for RT activity, preservation of several amino acid motifs in epidemiologically

  14. Energy renovation of Danish single-family houses Economy - barrier, motivation and limit

    DEFF Research Database (Denmark)

    Mortensen, Andrea; Heiselberg, Per Kvols; Plenge, Mary-Ann Knudstrup

    . The evaluation of the five concepts provided knowledge about the investment limit for private energy renovations and the limit for how much the homeowners think is acceptable to pay for the potential benefits and savings. The general picture is that the prices of the first three concepts (160.000 DKK, 120......From the results, it is clear that the knowledge about possible subsidies and counseling is not great among the respondents. They neither know about the possibilities to seek information and advice, nor do they know about the schemes from which grants are given in relation to energy savings...... of different kinds. There is however more knowledge about the economic grants than about the counseling, and some groups know more than others. The homeowners who have lived for less than one year in their current house have little knowledge about their opportunities and the longer the respondents have lived...

  15. A High-Speed Power-Line Communication System with Band-Limited OQAM Based Multi-Carrier Transmission

    Science.gov (United States)

    Kawabata, Naohiro; Koga, Hisao; Muta, Osamu; Akaiwa, Yoshihiko

    As a method to realize a high-speed communication in the home network, the power-line communication (PLC) technique is known. A problem of PLC is that leakage radiation interferes with existing systems. When OFDM is used in a PLC system, the leakage radiation is not sufficiently reduced, even if the subcarriers corresponding to the frequency-band of the existing system are never used, because the signal is not strictly band-limited. To solve this problem, each subcarrier must be band-limited. In this paper, we apply the OQAM based multi-carrier transmission (OQAM-MCT) to a high-speed PLC system, where each subcarrier is individually band-limited. We also propose a pilot-symbol sequence suitable for frequency offset estimation, symbol-timing detection and channel estimation in the OQAM-MCT system. In this method, the pilot signal-sequence consists of a repeated series of the same data symbol. With this method, the pilot sequence approximately becomes equivalent to OFDM sequence and therefore existing pilot-assisted methods for OFDM are also applicable to OQAM-MCT system. Computer simulation results show that the OQAM-MCT system achieves both good transmission rate performance and low out-of-band radiation in PLC channels. It is also shown that the proposed pilot-sequence improves frequency offset estimation, symbol-timing detection and channel estimation performance as compared with the case of using pseudo-noise sequence.

  16. Methicillin Resistant Staphylococcus aureus Transmission in a Ghanaian Burn Unit: The Importance of Active Surveillance in Resource-Limited Settings

    Directory of Open Access Journals (Sweden)

    Nana Ama Amissah

    2017-10-01

    Full Text Available Objectives:Staphylococcus aureus infections in burn patients can lead to serious complications and death. The frequency of S. aureus infection is high in low- and middle-income countries presumably due to limited resources, misuse of antibiotics and poor infection control. The objective of the present study was to apply population genomics to precisely define, for the first time, the transmission of antibiotic resistant S. aureus in a resource-limited setting in sub-Saharan Africa.Methods:Staphylococcus aureus surveillance was performed amongst burn patients and healthcare workers during a 7-months survey within the burn unit of the Korle Bu Teaching Hospital in Ghana.Results: Sixty-six S. aureus isolates (59 colonizing and 7 clinical were obtained from 31 patients and 10 healthcare workers. Twenty-one of these isolates were ST250-IV methicillin-resistant S. aureus (MRSA. Notably, 25 (81% of the 31 patients carried or were infected with S. aureus within 24 h of admission. Genome comparisons revealed six distinct S. aureus clones circulating in the burn unit, and demonstrated multiple transmission events between patients and healthcare workers. Further, the collected S. aureus isolates exhibited a wide range of genotypic resistances to antibiotics, including trimethoprim (21%, aminoglycosides (33%, oxacillin (33%, chloramphenicol (50%, tetracycline (59% and fluoroquinolones (100%.Conclusion: Population genomics uncovered multiple transmission events of S. aureus, especially MRSA, within the investigated burn unit. Our findings highlight lapses in infection control and prevention, and underscore the great importance of active surveillance to protect burn victims against multi-drug resistant pathogens in resource-limited settings.

  17. From Oxford to Hawaii ecophysiological barriers limit human progression in ten sport monuments.

    Science.gov (United States)

    Desgorces, François-Denis; Berthelot, Geoffroy; El Helou, Nour; Thibault, Valérie; Guillaume, Marion; Tafflet, Muriel; Hermine, Olivier; Toussaint, Jean-François

    2008-01-01

    In order to understand the determinants and trends of human performance evolution, we analyzed ten outdoor events among the oldest and most popular in sports history. Best performances of the Oxford-Cambridge boat race (since 1836), the channel crossing in swimming (1875), the hour cycling record (1893), the Elfstedentocht speed skating race (1909), the cross country ski Vasaloppet (1922), the speed ski record (1930), the Streif down-hill in Kitzbühel (1947), the eastward and westward sailing transatlantic records (1960) and the triathlon Hawaii ironman (1978) all follow a similar evolutive pattern, best described through a piecewise exponential decaying model (r(2) = 0.95+/-0.07). The oldest events present highest progression curvature during their early phase. Performance asymptotic limits predicted from the model may be achieved in fourty years (2049+/-32 y). Prolonged progression may be anticipated in disciplines which further rely on technology such as sailing and cycling. Human progression in outdoor sports tends to asymptotic limits depending on physiological and environmental parameters and may temporarily benefit from further technological progresses.

  18. Potential for Zika virus introduction and transmission in resource limited countries in Africa and Asia-Pacific: A modeling study

    Science.gov (United States)

    German, Matthew; Creatore, Maria I.; Brent, Shannon; Watts, Alexander G.; Hay, Simon I.; Kulkarni, Manisha A.; Brownstein, John S.; Khan, Kamran

    2016-01-01

    Summary Background As the epidemic of Zika virus expands in the Americas, countries across Africa and the Asia-Pacific region are becoming increasingly susceptible to the importation and possible local spread of the virus. To support public health readiness, we aim to identify regions and times where the potential health, economic, and social effects from Zika virus are greatest, focusing on resource-limited countries in Africa and the Asia-Pacific region. Methods Our model combined transportation network analysis, ecological modelling of mosquito occurrences, and vector competence for flavivirus transmission, using data from the International Air Transport Association, entomological observations from Zika’s primary vector species, and climate conditions using WorldClim. We overlaid monthly flows of airline travellers arriving to Africa and the Asia-Pacific region from areas of the Americas suitable for year-round transmission of Zika virus with monthly maps of climatic suitability for mosquito-borne transmission of Zika virus within Africa and the Asia-Pacific region. Findings An estimated 2·6 billion people live in areas of Africa and the Asia-Pacific region where the presence of competent mosquito vectors and suitable climatic conditions could support local transmission of Zika virus. Countries with large volumes of travellers arriving from Zika affected areas of the Americas and large populations at risk of mosquito-borne Zika virus infection include, India (67 422 travellers arriving per year; 1·2 billion residents in potential Zika transmission areas), China (238 415 travellers; 242 million residents), Indonesia (13 865 travellers; 197 million residents), Philippines (35 635 travellers; 70 million residents), and Thailand (29 241 travellers; 59 million residents). Interpretation Many countries across Africa and the Asia-Pacific region are vulnerable to Zika virus. Strategic use of available health and human resources is essential to prevent or mitigate

  19. APPLIED OPTICS. Overcoming Kerr-induced capacity limit in optical fiber transmission.

    Science.gov (United States)

    Temprana, E; Myslivets, E; Kuo, B P-P; Liu, L; Ataie, V; Alic, N; Radic, S

    2015-06-26

    Nonlinear optical response of silica imposes a fundamental limit on the information transfer capacity in optical fibers. Communication beyond this limit requires higher signal power and suppression of nonlinear distortions to prevent irreversible information loss. The nonlinear interaction in silica is a deterministic phenomenon that can, in principle, be completely reversed. However, attempts to remove the effects of nonlinear propagation have led to only modest improvements, and the precise physical mechanism preventing nonlinear cancellation remains unknown. We demonstrate that optical carrier stability plays a critical role in canceling Kerr-induced distortions and that nonlinear wave interaction in silica can be substantially reverted if optical carriers possess a sufficient degree of mutual coherence. These measurements indicate that fiber information capacity can be notably increased over previous estimates. Copyright © 2015, American Association for the Advancement of Science.

  20. Transmission Expansion Planning Considering Network Adequacy and Investment Cost Limitation using Genetic Algorithm

    OpenAIRE

    M. Mahdavi; E. Mahdavi

    2011-01-01

    In this research, STNEP is being studied considering network adequacy and limitation of investment cost by decimal codification genetic algorithm (DCGA). The goal is obtaining the maximum of network adequacy with lowest expansion cost for a specific investment. Finally, the proposed idea is applied to the Garvers 6-bus network. The results show that considering the network adequacy for solution of STNEP problem is caused that among of expansion plans for a determined investment, configuration...

  1. Limited potential for transmission of live dengue virus vaccine candidates by Aedes aegypti and Aedes albopictus.

    Science.gov (United States)

    Sardelis, M R; Edelman, R; Klein, T A; Innis, B L; Putnak, J R; Jones, J W; Turell, M J

    2000-06-01

    To evaluate the transmission risk of four live dengue (DEN) vaccine candidates developed by the U.S. Army (DEN-1, 45AZ5 PDK 20; DEN-2, S16803 PDK 50; DEN-3, CH53489 PDK 20; and DEN-4, 341750 PDK 20), we tested 3,010 Aedes aegypti and 1,576 Aedes albopictus mosquitoes blood-fed on 21 volunteers who had been administered one of the four vaccine candidates or the licensed yellow fever (YF) vaccine (17D). We used an indirect immunofluorescence assay (IFA) to detect DEN or YF viral antigen in the heads of mosquitoes. Corresponding to the lack of a detectable viremia among volunteers inoculated 8-13 days previously with live DEN-1 or DEN-2 vaccine candidates, only six mosquitoes developed disseminated infections after feeding on these volunteers. These six mosquitoes included 4 of 247 Ae. albopictus fed on volunteers inoculated with the DEN-1 vaccine candidate and 2 of 528 Ae. aegypti fed on volunteers inoculated with the DEN-2 vaccine candidate. Infection was confirmed in each of these IFA-positive mosquitoes by isolating infectious virus from the mosquito's body in Vero-cell culture. None of the 1,252 or the 969 mosquitoes fed on DEN-3 or DEN-4 recipients, respectively, were infected. Overall, dissemination rates in Ae. albopictus and Ae. aegypti were low. Dissemination rates were 0.5%, 0.3%, < 0.1%, and < 0.1% for the DEN-1 through DEN-4 vaccine candidates, respectively. Because of the observed low dissemination rates, it is unlikely that these vaccine viruses would be transmitted under natural conditions.

  2. Barriers and facilitating factors to the uptake of antiretroviral drugs for prevention of mother-to-child transmission of HIV in sub-Saharan Africa: a systematic review

    Science.gov (United States)

    Gourlay, Annabelle; Birdthistle, Isolde; Mburu, Gitau; Iorpenda, Kate; Wringe, Alison

    2013-01-01

    Objectives To investigate and synthesize reasons for low access, initiation and adherence to antiretroviral drugs by mothers and exposed babies for prevention of mother-to-child transmission (PMTCT) of HIV in sub-Saharan Africa. Methods A systematic literature review was conducted. Four databases were searched (Medline, Embase, Global Health and Web of Science) for studies conducted in sub-Saharan Africa from January 2000 to September 2012. Quantitative and qualitative studies were included that met pre-defined criteria. Antiretroviral (ARV) prophylaxis (maternal/infant) and combination antiretroviral therapy (ART) usage/registration at HIV care and treatment during pregnancy were included as outcomes. Results Of 574 references identified, 40 met the inclusion criteria. Four references were added after searching reference lists of included articles. Twenty studies were quantitative, 16 were qualitative and eight were mixed methods. Forty-one studies were conducted in Southern and East Africa, two in West Africa, none in Central Africa and one was multi-regional. The majority (n=25) were conducted before combination ART for PMTCT was emphasized in 2006. At the individual-level, poor knowledge of HIV/ART/vertical transmission, lower maternal educational level and psychological issues following HIV diagnosis were the key barriers identified. Stigma and fear of status disclosure to partners, family or community members (community-level factors) were the most frequently cited barriers overall and across time. The extent of partner/community support was another major factor impeding or facilitating the uptake of PMTCT ARVs, while cultural traditions including preferences for traditional healers and birth attendants were also common. Key health-systems issues included poor staff-client interactions, staff shortages, service accessibility and non-facility deliveries. Conclusions Long-standing health-systems issues (such as staffing and service accessibility) and community

  3. A Lifetime Optimization Algorithm Limited by Data Transmission Delay and Hops for Mobile Sink-Based Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yourong Chen

    2017-01-01

    Full Text Available To improve the lifetime of mobile sink-based wireless sensor networks and considering that data transmission delay and hops are limited in actual system, a lifetime optimization algorithm limited by data transmission delay and hops (LOA_DH for mobile sink-based wireless sensor networks is proposed. In LOA_DH, some constraints are analyzed, and an optimization model is proposed. Maximum capacity path routing algorithm is used to calculate the energy consumption of communication. Improved genetic algorithm which modifies individuals to meet all constraints is used to solve the optimization model. The optimal solution of sink node’s sojourn grid centers and sojourn times which maximizes network lifetime is obtained. Simulation results show that, in three node distribution scenes, LOA_DH can find the movement solution of sink node which covers all sensor nodes. Compared with MCP_RAND, MCP_GMRE, and EASR, the solution improves network lifetime and reduces average amount of node discarded data and average energy consumption of nodes.

  4. Development and Testing of a Transmission Voltage SuperLimiter™ Fault Current Limiter

    Energy Technology Data Exchange (ETDEWEB)

    Romanosky, Walter [American Superconductor Corporation, Devens, MA (United States)

    2012-09-01

    This report summarizes work by American Superconductor (AMSC), Los Alamos National Laboratory (LANL), Nexans, Siemens and Southern California Edison on a 138kV resistive type high temperature superconductor (HTS) fault current limiter (FCL) under a cooperative agreement with the U.S. Department of Energy (DOE). Phase 1A encompassed core technology development and system design and was previously reported (see summary that follows in Section 1.1 of the Introduction). This report primarily discusses work performed during Phase 1B, and addresses the fabrication and test of a single-phase prototype FCL. The results are presented along with a discussion of requirements/specifications and lessons learned to aid future development and product commercialization.

  5. UK Iatrogenic Creutzfeldt-Jakob disease: investigating human prion transmission across genotypic barriers using human tissue-based and molecular approaches.

    Science.gov (United States)

    Ritchie, Diane L; Barria, Marcelo A; Peden, Alexander H; Yull, Helen M; Kirkpatrick, James; Adlard, Peter; Ironside, James W; Head, Mark W

    2017-04-01

    Creutzfeldt-Jakob disease (CJD) is the prototypic human prion disease that occurs most commonly in sporadic and genetic forms, but it is also transmissible and can be acquired through medical procedures, resulting in iatrogenic CJD (iCJD). The largest numbers of iCJD cases that have occurred worldwide have resulted from contaminated cadaveric pituitary-derived human growth hormone (hGH) and its use to treat primary and secondary growth hormone deficiency. We report a comprehensive, tissue-based and molecular genetic analysis of the largest series of UK hGH-iCJD cases reported to date, including in vitro kinetic molecular modelling of genotypic factors influencing prion transmission. The results show the interplay of prion strain and host genotype in governing the molecular, pathological and temporal characteristics of the UK hGH-iCJD epidemic and provide insights into the adaptive mechanisms involved when prions cross genotypic barriers. We conclude that all of the available evidence is consistent with the hypothesis that the UK hGH-iCJD epidemic resulted from transmission of the V2 human prion strain, which is associated with the second most common form of sporadic CJD.

  6. A novel concept of fault current limiter based on saturable core in high voltage DC transmission system

    Science.gov (United States)

    Yuan, Jiaxin; Zhou, Hang; Gan, Pengcheng; Zhong, Yongheng; Gao, Yanhui; Muramatsu, Kazuhiro; Du, Zhiye; Chen, Baichao

    2018-05-01

    To develop mechanical circuit breaker in high voltage direct current (HVDC) system, a fault current limiter is required. Traditional method to limit DC fault current is to use superconducting technology or power electronic devices, which is quite difficult to be brought to practical use under high voltage circumstances. In this paper, a novel concept of high voltage DC transmission system fault current limiter (DCSFCL) based on saturable core was proposed. In the DCSFCL, the permanent magnets (PM) are added on both up and down side of the core to generate reverse magnetic flux that offset the magnetic flux generated by DC current and make the DC winding present a variable inductance to the DC system. In normal state, DCSFCL works as a smoothing reactor and its inductance is within the scope of the design requirements. When a fault occurs, the inductance of DCSFCL rises immediately and limits the steepness of the fault current. Magnetic field simulations were carried out, showing that compared with conventional smoothing reactor, DCSFCL can decrease the high steepness of DC fault current by 17% in less than 10ms, which verifies the feasibility and effectiveness of this method.

  7. Podocyte-specific overexpression of metallothionein mitigates diabetic complications in the glomerular filtration barrier and glomerular histoarchitecture: a transmission electron microscopy stereometric analysis.

    Science.gov (United States)

    Carlson, Edward C; Chhoun, Jennifer M; Laturnus, Donna I; Bikash, K C; Berg, Brittany; Zheng, Shirong; Epstein, Paul N

    2013-02-01

    We previously demonstrated that cellular and extracellular components of the blood-urine barrier in renal glomeruli are susceptible to damage in OVE transgenic mice, a valuable model of human diabetic nephropathy that expresses profound albuminuria. To test our hypothesis that glomerular filtration barrier damage in OVE mice may be the result of oxidative insult to podocytes, 150-day-old bi-transgenic OVENmt diabetic mice that overexpress the antioxidant metallothionein specifically in podocytes were examined by enzyme-linked immunosorbent assay for albuminuria mitigation and by unbiased transmission electron microscopy (TEM) stereometry for protection from chronic structural diabetic complications. Although blood glucose and HbA(1c) levels were indistinguishable in OVE and OVENmt animals, albuminuria was significantly reduced (average >7-fold) in OVENmt mice through 8 months of age. Interestingly, the Nmt transgene provided significant glomerular protection against diabetic nephropathic complications outside of the podocyte. Glomerular filtration barrier damage was reduced in OVENmt mice, including significantly increased area occupied by endothelial luminal fenestrations (~13%), significantly reduced glomerular basement membrane (GBM) thickening (~17%) and significantly less podocyte effacement (~18%). In addition, OVENmt mice exhibited significantly reduced glomerular volume (~50%), fewer glomerular endothelial cells (~33%), fewer mesangial cells (~57%) and fewer total glomerular cells (~40%). These results provide evidence of oxidative damage to podocytes induces primary diabetic nephropathic features including severe and sustained albuminuria, specific glomerular filtration barrier damage and alterations in glomerular endothelial and mesangial cell number. Importantly, these diabetic complications are significantly mitigated by podocyte targeted metallothionein overexpression. Copyright © 2012 John Wiley & Sons, Ltd.

  8. On the front line of HIV virological monitoring: barriers and facilitators from a provider perspective in resource-limited settings.

    Science.gov (United States)

    Rutstein, S E; Golin, C E; Wheeler, S B; Kamwendo, D; Hosseinipour, M C; Weinberger, M; Miller, W C; Biddle, A K; Soko, A; Mkandawire, M; Mwenda, R; Sarr, A; Gupta, S; Mataya, R

    2016-01-01

    Scale-up of viral load (VL) monitoring for HIV-infected patients on antiretroviral therapy (ART) is a priority in many resource-limited settings, and ART providers are critical to effective program implementation. We explored provider-perceived barriers and facilitators of VL monitoring. We interviewed all providers (n = 17) engaged in a public health evaluation of dried blood spots for VL monitoring at five ART clinics in Malawi. All ART clinics were housed within district hospitals. We grouped themes at patient, provider, facility, system, and policy levels. Providers emphasized their desire for improved ART monitoring strategies, and frustration in response to restrictive policies for determining which patients were eligible to receive VL monitoring. Although many providers pled for expansion of monitoring to include all persons on ART, regardless of time on ART, the most salient provider-perceived barrier to VL monitoring implementation was the pressure of work associated with monitoring activities. The work burden was exacerbated by inefficient data management systems, highlighting a critical interaction between provider-, facility-, and system-level factors. Lack of integration between laboratory and clinical systems complicated the process for alerting providers when results were available, and these communication gaps were intensified by poor facility connectivity. Centralized second-line ART distribution was also noted as a barrier: providers reported that the time and expenses required for patients to collect second-line ART frequently obstructed referral. However, provider empowerment emerged as an unexpected facilitator of VL monitoring. For many providers, this was the first time they used an objective marker of ART response to guide clinical management. Providers' knowledge of a patient's virological status increased confidence in adherence counseling and clinical decision-making. Results from our study provide unique insight into provider

  9. Reduced water vapor transmission rates of low-temperature solution-processed metal oxide barrier films via ultraviolet annealing

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seonuk; Jeong, Yong Jin; Baek, Yonghwa; Kim, Lae Ho; Jang, Jin Hyuk; Kim, Yebyeol [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of); An, Tae Kyu [Department of Polymer Science & Engineering, Korea National University of Transportation, 50 Daehak-Ro, Chungju (Korea, Republic of); Nam, Sooji, E-mail: sjnam15@etri.re.kr [Information Control Device Section, Electronics and Telecommunications Research Institute, Daejeon, 305-700 (Korea, Republic of); Kim, Se Hyun, E-mail: shkim97@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan, North Gyeongsang 712-749 (Korea, Republic of); Jang, Jaeyoung, E-mail: jyjang15@hanyang.ac.kr [Department of Energy Engineering, Hanyang University, Seoul, 133-791 (Korea, Republic of); Park, Chan Eon, E-mail: cep@postech.ac.kr [POSTECH Organic Electronics Laboratory, Polymer Research Institute, Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, 790-784 (Korea, Republic of)

    2017-08-31

    Highlights: • Sol-gel-derived aluminum oxide thin films were prepared using ultraviolet (UV) annealing. • UV irradiation dramatically promoted the densification of AlO{sub x} during the annealing stage, thereby forming a close-packed AlO{sub x} film. • The resulting AlO{sub x} films deposited on polymer substrates exhibited good water vapor blocking properties with low water vapor transmission rates (WVTRs). - Abstract: Here, we report the fabrication of low-temperature sol-gel-derived aluminum oxide (AlO{sub x}) films via ultraviolet (UV) annealing and the investigation of their water vapor blocking properties by measuring the water vapor transmission rates (WVTRs). The UV annealing process induced the formation of a dense metal-oxygen-metal bond (Al-O-Al structure) at low temperatures (<200 °C) that are compatible with commercial plastic substrates. The density of the UV-annealed AlO{sub x} thin film at 180 °C was comparable to that of AlO{sub x} thin films that have been thermally annealed at 350 °C. Furthermore, the UV-annealed AlO{sub x} thin films exhibited a high optical transparency in the visible region (>99%) and good electrical insulating properties (∼10{sup −7} A/cm{sup 2} at 2 MV/cm). Finally, we confirmed that a dense AlO{sub x} thin film was successfully deposited onto the plastic substrate via UV annealing at low temperatures, leading to a substantial reduction in the WVTRs. The Ca corrosion test was used to measure the WVTRs of AlO{sub x} thin films deposited onto polyethylene naphthalate or polyimide substrates, determined to be 0.0095 g m{sup −2} day{sup −1} (25 °C, 50% relative humidity) and 0.26 g m{sup −2} day{sup −1}, respectively.

  10. Multiple blood-brain barrier transport mechanisms limit bumetanide accumulation, and therapeutic potential, in the mammalian brain.

    Science.gov (United States)

    Römermann, Kerstin; Fedrowitz, Maren; Hampel, Philip; Kaczmarek, Edith; Töllner, Kathrin; Erker, Thomas; Sweet, Douglas H; Löscher, Wolfgang

    2017-05-01

    There is accumulating evidence that bumetanide, which has been used over decades as a potent loop diuretic, also exerts effects on brain disorders, including autism, neonatal seizures, and epilepsy, which are not related to its effects on the kidney but rather mediated by inhibition of the neuronal Na-K-Cl cotransporter isoform NKCC1. However, following systemic administration, brain levels of bumetanide are typically below those needed to inhibit NKCC1, which critically limits its clinical use for treating brain disorders. Recently, active efflux transport at the blood-brain barrier (BBB) has been suggested as a process involved in the low brain:plasma ratio of bumetanide, but it is presently not clear which transporters are involved. Understanding the processes explaining the poor brain penetration of bumetanide is needed for developing strategies to improve the brain delivery of this drug. In the present study, we administered probenecid and more selective inhibitors of active transport carriers at the BBB directly into the brain of mice to minimize the contribution of peripheral effects on the brain penetration of bumetanide. Furthermore, in vitro experiments with mouse organic anion transporter 3 (Oat3)-overexpressing Chinese hamster ovary cells were performed to study the interaction of bumetanide, bumetanide derivatives, and several known inhibitors of Oats on Oat3-mediated transport. The in vivo experiments demonstrated that the uptake and efflux of bumetanide at the BBB is much more complex than previously thought. It seems that both restricted passive diffusion and active efflux transport, mediated by Oat3 but also organic anion-transporting polypeptide (Oatp) Oatp1a4 and multidrug resistance protein 4 explain the extremely low brain concentrations that are achieved after systemic administration of bumetanide, limiting the use of this drug for targeting abnormal expression of neuronal NKCC1 in brain diseases. Copyright © 2017 Elsevier Ltd. All rights

  11. Limiter

    Science.gov (United States)

    Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.

    1984-10-19

    A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

  12. Attitudes of Female Faculty toward the Use of Computer Technologies and the Barriers that Limit Their Use of Technologies in Girls' Colleges in Saudi Arabia

    Science.gov (United States)

    Almuqayteeb, Taghreed Abdulaziz

    2009-01-01

    The purpose of this study was to examine female faculty members' use of computer technologies, their attitudes toward computers, the factors that best predict their attitudes toward computers, and the barriers that limit their use of computer technologies in girls' colleges in Dammam and Jubail, Saudi Arabia. Also, this study examined how female…

  13. Limited Understanding of Pap Smear Testing among Women, a Barrier to Cervical Cancer Screening in the United Arab Emirates

    Science.gov (United States)

    AL-Hammadi, Fatima Ahmed; Al-Tahri, Fatema; Al-Ali, Asma; Nair, Satish C; Abdulrahman, Mahera

    2017-12-29

    Global data indicate that cervical cancer is the fourth most common cancer among women worldwide. Important factors that affect interventions for early diagnosis of cervical cancer include social beliefs and values and poor knowledge. These may contribute to women’s participation in screening for cervical cancer and have a significant impact on decisions to take preventive action. The present study was conducted with 599 women in the UAE between September 2016 and March 2017. A cross-sectional survey was conducted to determine knowledge about cervical cancer and screening, demographic characteristics and perceived barriers. Knowledge about the Pap smear test was limited, and awareness that they should undergo the Pap smear test every three years even with an initial negative/normal Pap smear result was abysmal. In spite of the positive attitude of the women towards the Pap smear test, almost 80% of the women surveyed had no knowledge of precancerous lesions. Having higher income (21/29, 72%, p=0.027) and more miscarriages were associated with better practice of Pap smears (19/26, 73%, p=0.010). Knowledge levels were significantly higher (66.3±22.2,) that values for attitude (60.5±20.9, p= 0.03, 95% CI {0.22-11.3}, Chi-square 4.38) and practice (53.7 24.1, p= 0.001, 95% CI {6.9-18.1}, Chi-square 19.7). A well-designed health education programme on cervical cancer and benefits of screening should increase the awareness among women in UAE. One point to stress is that better communication with health professionals and improvement of access to health care services should increase the rate of cervical cancer screening. Creative Commons Attribution License

  14. Community voices: barriers and opportunities for programmes to successfully prevent vertical transmission of HIV identified through consultations among people living with HIV.

    Science.gov (United States)

    Anderson, Ginna; Caswell, Georgina; Edwards, Olive; Hsieh, Amy; Hull, Beri; Mallouris, Christoforos; Mason, Naisiadet; Nöstlinger, Christiana

    2012-07-11

    In 2010, two global networks of people living with HIV, the International Community of Women Living with HIV (ICW Global) and the Global Network of People living with HIV (GNP+) were invited to review a draft strategic framework for the global scale up of prevention of vertical transmission (PVT) through the primary prevention of HIV and the prevention of unintended pregnancies among women living with HIV. In order to ensure recommendations were based on expressed needs of people living with HIV, GNP+ and ICW Global undertook a consultation amongst people living with HIV which highlighted both facilitators and barriers to prevention services. This commentary summarizes the results of that consultation. The consultation was comprised of an online consultation (moderated chat-forum with 36 participants from 16 countries), an anonymous online e-survey (601 respondents from 58 countries), and focus-group discussions with people living with HIV in Jamaica (27 participants). The consultation highlighted the discrepancies across regions with respect to access to essential packages of PVT services. However, the consultation participants also identified common barriers to access, including a lack of trustworthy sources of information, service providers' attitudes, and gender-based violence. In addition, participant responses revealed common facilitators of access, including quality counselling on reproductive choices, male involvement, and decentralized services. The consultation provided some understanding and insight into the participants' experiences with and recommendations for PVT strategies. Participants agreed that successful, comprehensive PVT programming require greater efforts to both prevent primary HIV infection among young women and girls and, in particular, targeted efforts to ensure that women living with HIV and their partners are supported to avoid unintended pregnancies and to have safe, healthy pregnancies instead. In addition to providing the insights

  15. The HIV-1 transmission bottleneck

    OpenAIRE

    Kariuki, Samuel Mundia; Selhorst, Philippe; Ari?n, Kevin K.; Dorfman, Jeffrey R.

    2017-01-01

    It is well established that most new systemic infections of HIV-1 can be traced back to one or a limited number of founder viruses. Usually, these founders are more closely related to minor HIV-1 populations in the blood of the presumed donor than to more abundant lineages. This has led to the widely accepted idea that transmission selects for viral characteristics that facilitate crossing the mucosal barrier of the recipient?s genital tract, although the specific selective forces or advantag...

  16. Reinforcement of the Gas Barrier Properties of Polyethylene and Polyamide Through the Nanocomposite Approach: Key Factors and Limitations

    Directory of Open Access Journals (Sweden)

    Picard E.

    2015-02-01

    Full Text Available In this study, polyamide 6 (PA6 and polyethylene (PE nanocomposites were prepared from melt blending and a detailed characterization of the nanocomposite morphology and gas barrier properties was performed. The choice of the organoclay was adapted to each polymer matrix. Exfoliated morphology and improved gas transport properties were obtained by melt mixing the polar PA6 matrix and the organoclay, whereas a microcomposite with poor barrier properties was formed from the binary PE/organomodified clay mixture. Different modified polyethylenes were examined as compatibilizers for the polyethylene/organoclay system. The effect of compatibilizer molar mass, polarity and content was investigated on the clay dispersion and on the gas barrier properties. The optimal compatibilizer to clay weight ratio was found to be equal to 4 whatever the compatibilizer. However, a high degree of clay delamination was obtained with the high molar mass compatibilizer whereas highly swollen clay aggregates resulted from the incorporation of the low molar mass interfacial agents. Contrary to the PA based system, the barrier properties of PE nanocomposites were not directly related to the clay dispersion state but resulted also from the matrix/clay interfacial interactions. Oxidized wax was identified as a very promising interfacial agent and a step by step study was performed to optimize the gas transport properties of the systems based on PE, oxidized wax and organoclay. In particular, an interesting combination of oxidized wax and high molar mass maleic anhydride grafted polyethylene allowing dividing the gas permeability by a factor 2 in comparison with neat PE was proposed.

  17. Limitations of the hCMEC/D3 cell line as a model for Aβ clearance by the human blood-brain barrier.

    Science.gov (United States)

    Biemans, Elisanne A L M; Jäkel, Lieke; de Waal, Robert M W; Kuiperij, H Bea; Verbeek, Marcel M

    2017-07-01

    Alzheimer's disease and cerebral amyloid angiopathy are characterized by accumulation of amyloid-β (Aβ) at the cerebrovasculature due to decreased clearance at the blood-brain barrier (BBB). However, the exact mechanism of Aβ clearance across this barrier has not been fully elucidated. The hCMEC/D3 cell line has been characterized as a valid model for the BBB. In this study we evaluated the use of this model to study Aβ clearance across the BBB, with an emphasis on brain-to-blood directional permeability. Barrier integrity of hCMEC/D3 monolayers was confirmed for large molecules in both the apical to basolateral and the reverse direction. However, permeability for smaller molecules was substantially higher, especially in basolateral to apical direction, and barrier formation for Aβ was completely absent in this direction. In addition, hCMEC/D3 cells failed to develop a high TEER, possibly caused by incomplete formation of tight junctions. We conclude that the hCMEC/D3 model has several limitations to study the cerebral clearance of Aβ. Therefore, the model needs further characterization before this cell system can be generally applied as a model to study cerebral Aβ clearance. © 2016 The Authors Journal of Neuroscience Research Published by Wiley Periodicals, Inc. © 2016 The Authors Journal of Neuroscience Research Published by Wiley Periodicals, Inc.

  18. Transmission of drug resistant HIV and its potential impact on mortality and treatment outcomes in resource-limited settings

    DEFF Research Database (Denmark)

    Cambiano, Valentina; Bertagnolio, Silvia; Jordan, Michael R

    2013-01-01

    the prevalence of resistance in ART-naive people is reaching alerting levels. Whereas adherence counseling has to be an integral component of any treatment program, it is still unclear which threshold of transmitted drug resistance (TDR) should trigger additional targeted public health actions and which action...... is the most cost-effective. Mathematical models can contribute to answer these questions. In order to estimate the potential long-term impact of TDR on mortality in people on ART we used the Synthesis transmission model. TDR is predicted to have potentially significant impact on future HIV mortality....... It is critical to remain vigilant over transmission of drug-resistant HIV....

  19. Navigating the risks of prevention of mother to child transmission (PMTCT) of HIV services in Kibera, Kenya: Barriers to engaging and remaining in care.

    Science.gov (United States)

    Thomson, Kerry A; Telfer, Barbara; Opondo Awiti, Patricia; Munge, Jane; Ngunga, Mathew; Reid, Anthony

    2018-01-01

    Within the first year of implementation, 43% of women who tested HIV positive at their first antenatal care visit were no longer retained and being followed in the free prevention of mother to child transmission (PMTCT) of HIV program offered by the Kenyan Ministry of Health and Médecins Sans Frontières in the informal settlement of Kibera, Nairobi. This study aimed to explore barriers to enrolling and remaining engaged in PMTCT services throughout the pregnancy and postpartum periods. Qualitative data from 31 focus group discussions and 35 in-depth interviews across six stakeholder groups that included women, men, and PMTCT service providers were analyzed. Using an inductive exploratory approach, four researchers coded the data and identified key themes. Five themes emerged from the data that may influence attrition from PMTCT service in this setting: 1) HIV in the context of Kibera, 2) knowledge of HIV status, 3) knowledge of PMTCT, 4) disclosure of HIV status, and 5) male partner support for PMTCT services. A new HIV diagnosis during pregnancy immediately triggered an ongoing risk assessment of perceived hazards in the home, community, and clinic environments that could occur as a result of female participation in PMTCT services. Male partners were a major influence in this risk assessment, but were generally unaware of PMTCT services. To preserve relationships with male partners, meet community expectations of womanhood, and maintain confidentiality while following recommendations of healthcare providers, women had to continuously weigh the risks and benefits of PMTCT services and interventions. Community-based HIV testing and PMTCT education, male involvement in antenatal care, and counseling customized to assist each woman in her own unique risk assessment, may improve uptake of and retention in care and optimize the HIV prevention benefit of PMTCT interventions.

  20. Economic and social factors are some of the most common barriers preventing women from accessing maternal and newborn child health (MNCH) and prevention of mother-to-child transmission (PMTCT) services: a literature review.

    Science.gov (United States)

    hIarlaithe, Micheal O; Grede, Nils; de Pee, Saskia; Bloem, Martin

    2014-10-01

    Support to health programming has increasingly placed an emphasis on health systems strengthening. Integration of prevention of mother-to-child transmission (PMTCT) and maternal and newborn child health (MNCH) services has been one of the areas where there has been a shift from a siloed to a more integrated approach. The scale-up of anti-retroviral therapy has made services increasingly available while also bringing them closer to those in need. However, addressing supply side issues around the availability and quality of care at the health centre level alone cannot guarantee better results without a more explicit focus on access issues. Access to PMTCT care and treatment services is affected by a number of barriers which influence decisions of women to seek care. This paper reviews published qualitative and quantitative studies that look at demand side barriers to PMTCT services and proposes a categorisation of these barriers. It notes that access to PMTCT services as well as eventual uptake and retention in PMTCT care starts with access to MNCH in general. While poverty often prevents women, regardless of HIV status, from accessing MNCH services, women living with HIV who are in need of PMTCT services face an additional set of PMTCT barriers. This review proposes four categories of barriers to accessing PMTCT: social norms and knowledge, socioeconomic status, physiological status and psychological conditions. Social norms and knowledge and socioeconomic status stand out. Transport is the most frequently mentioned socioeconomic barrier. With regard to social norms and knowledge, non-disclosure, stigma and partner relations are the most commonly cited barriers. Some studies also cite physiological barriers. Barriers related to social norms and knowledge, socioeconomic status and physiology can all be affected by the mental and psychological state of the individual to create a psychological barrier to access. Increased coverage and uptake of PMTCT services can be

  1. Phonon tunneling through a double barrier system

    Energy Technology Data Exchange (ETDEWEB)

    Villegas, Diosdado [Departamento de Física, Universidad Central “Marta Abreu” de Las Villas, CP 54830, Santa Clara, Villa Clara (Cuba); Instituto de Física, Universidad Autónoma de Puebla, 18 Sur y San Claudio, Edif. 110A, Ciudad Universitaria, 72570 Puebla (Mexico); León-Pérez, Fernando de [Centro Universitario de la Defensa de Zaragoza, Ctra. de Huesca s/n, E-50090 Zaragoza (Spain); Pérez-Álvarez, R. [Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, CP 62209 Cuernavaca (Mexico); Arriaga, J., E-mail: arriaga@ifuap.buap.mx [Instituto de Física, Universidad Autónoma de Puebla, 18 Sur y San Claudio, Edif. 110A, Ciudad Universitaria, 72570 Puebla (Mexico)

    2015-04-15

    The tunneling of optical and acoustic phonons at normal incidence on a double-barrier is studied in this paper. Transmission coefficients and resonance conditions are derived theoretically under the assumption that the long-wavelength approximation is valid. It is shown that the behavior of the transmission coefficients for the symmetric double barrier has a Lorentzian form close to resonant frequencies and that Breit–Wigner's formula have a general validity in one-dimensional phonon tunneling. Authors also study the so-called generalized Hartman effect in the tunneling of long-wavelength phonons and show that this effect is a numerical artifact resulting from taking the opaque limit before exploring the variation with a finite barrier width. This study could be useful for the design of acoustic devices.

  2. Phonon tunneling through a double barrier system

    International Nuclear Information System (INIS)

    Villegas, Diosdado; León-Pérez, Fernando de; Pérez-Álvarez, R.; Arriaga, J.

    2015-01-01

    The tunneling of optical and acoustic phonons at normal incidence on a double-barrier is studied in this paper. Transmission coefficients and resonance conditions are derived theoretically under the assumption that the long-wavelength approximation is valid. It is shown that the behavior of the transmission coefficients for the symmetric double barrier has a Lorentzian form close to resonant frequencies and that Breit–Wigner's formula have a general validity in one-dimensional phonon tunneling. Authors also study the so-called generalized Hartman effect in the tunneling of long-wavelength phonons and show that this effect is a numerical artifact resulting from taking the opaque limit before exploring the variation with a finite barrier width. This study could be useful for the design of acoustic devices

  3. Scale up use of family planning services to prevent maternal transmission of HIV among discordant couples: a cross-sectional study within a resource-limited setting

    Directory of Open Access Journals (Sweden)

    Kuete M

    2016-10-01

    Full Text Available Martin Kuete,1,2 HongFang Yuan,1 Aude Laure Tchoua Kemayou,2 Emmanuel Ancel Songo,2 Fan Yang,1 XiuLan Ma,1 ChengLiang Xiong,1 HuiPing Zhang1 1Obstetrics and Gynecology, Reproductive Center, Family Planning and Research Institute, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People’s Republic of China; 2Main Maternity of Obstetrics and Gynecology, Yaounde Central Hospital, Faculty of Medicine and Biomedical Sciences, Yaounde, Cameroon Background: Integration of family planning services (FPS into human immunodeficiency virus (HIV care for HIV-infected women is an important aspect of the global prevention of mother-to-child transmission (PMTCT strategy. We assessed the integration of FPS into routine care of HIV-infected mothers by evaluating the uptake and barriers of contraception and PMTCT services. Methods: We conducted an interventional study using the interrupted time series approach in the health care facilities located in Yaounde, Cameroon. First, structured questionnaires related to family planning use, PMTCT services use, and infection risk of the sexual partner were administered to the first trimester pregnant women who were HIV infected and living with uninfected partners. Second, 2 weeks before the delivery date, the women were interviewed according to the prior counseling interventions received, in order to assess their behavior on FPS, antiretroviral therapy (ART use, delivery option, and infant nourishment to be adopted. P-values below 0.05 were considered statistically significant in the statistical analyses. Results: Of 94 HIV-infected women, 69% were stable couples. Only 13% of women had attended FPS before conception. Although the vast majority were knowledgeable about modern and traditional contraception methods, only 19% had experienced effective contraceptive methods. However, 66% preferred condom use, 45% having three children still expressed a desire to conceive, while 44% reported

  4. Experimental Research and Control Strategy of Pumped Storage Units Dispatching in the Taiwan Power System Considering Transmission Line Limits

    Directory of Open Access Journals (Sweden)

    Ming-Tse Kuo

    2013-07-01

    Full Text Available Taiwan’s power system is isolated and not supported by other interconnected systems. Consequently, the system frequency immediately reflects changes in the system loads. Pumped storage units are crucial for controlling power frequency. These units provide main or auxiliary capacities, reducing the allocation of frequency-regulating reserve (FRR and further reducing generation costs in system operations. Taiwan’s Longmen Nuclear Power Plant is set to be converted for commercial operations, which will significantly alter the spinning reserves in the power system. Thus, this study proposes a safe and economic pumped storage unit dispatch strategy. This strategy is used to determine the optimal FRR capacity and 1-min recovery frequency in a generator failure occurrence at the Longmen Power Plant. In addition, this study considered transmission capacity constraints and conducted power flow analysis of the power systems in Northern, Central, and Southern Taiwan. The results indicated that, in the event of a failure at Longmen Power Plant, the proposed strategy can not only recover the system frequency to an acceptable range to prevent underfrequency load-shedding, but can also mitigate transmission line overloading.

  5. Absence of zero-temperature transmission rate of a double-chain tight-binding model for DNA with random sequence of nucleotides in thermodynamic limit

    International Nuclear Information System (INIS)

    Xiong Gang; Wang, X.R.

    2005-01-01

    The zero-temperature transmission rate spectrum of a double-chain tight-binding model for real DNA is calculated. It is shown that a band of extended-like states exists only for finite chain length with strong inter-chain coupling. While the whole spectrum tends to zero in thermodynamic limit, regardless of the strength of inter-chain coupling. It is also shown that a more faithful model for real DNA with periodic sugar-phosphate chains in backbone structures can be mapped into the above simple double-chain tight-binding model. Combined with above results, the transmission rate of real DNA with long random sequence of nucleotides is expected to be poor

  6. Internal photoemission for photovoltaic using p-type Schottky barrier: Band structure dependence and theoretical efficiency limits

    Science.gov (United States)

    Shih, Ko-Han; Chang, Yin-Jung

    2018-01-01

    Solar energy conversion via internal photoemission (IPE) across a planar p-type Schottky junction is quantified for aluminum (Al) and copper (Cu) in the framework of direct transitions with non-constant matrix elements. Transition probabilities and k-resolved group velocities are obtained based on pseudo-wavefunction expansions and realistic band structures using the pseudopotential method. The k-resolved number of direct transitions, hole photocurrent density, quantum yield (QY), and the power conversion efficiency (PCE) under AM1.5G solar irradiance are subsequently calculated and analyzed. For Al, the parabolic and "parallel-band" effect along the U-W-K path significantly enhances the transition rate with final energies of holes mainly within 1.41 eV below the Fermi energy. For Cu, d-state hot holes mostly generated near the upper edge of 3d bands dominate the hole photocurrent and are weekly (strongly) dependent on the barrier height (metal film thickness). Hot holes produced in the 4s band behave just oppositely to their d-state counterparts. Non-constant matrix elements are shown to be necessary for calculations of transitions due to time-harmonic perturbation in Cu. Compared with Cu, Al-based IPE in p-type Schottky shows the highest PCE (QY) up to about 0.2673% (5.2410%) at ΦB = 0.95 eV (0.5 eV) and a film thickness of 11 nm (20 nm). It is predicted that metals with relatively dispersionless d bands (such as Cu) in most cases do not outperform metals with photon-accessible parallel bands (such as Al) in photon energy conversion using a planar p-type Schottky junction.

  7. Barriers to access prevention of mother-to-child transmission for HIV positive women in a well-resourced setting in Vietnam.

    Science.gov (United States)

    Nguyen, Thu Anh; Oosterhoff, Pauline; Ngoc, Yen Pham; Wright, Pamela; Hardon, Anita

    2008-04-17

    According to Vietnamese policy, HIV-infected women should have access at least to HIV testing and Nevirapine prophylaxis, or where available, to adequate counselling, HIV infection staging, ARV prophylaxis, and infant formula. Many studies in high HIV prevalence settings have reported low coverage of PMTCT services, but there have been few reports from low HIV prevalence settings, such as Asian countries. We investigated the access of HIV-infected pregnant women to PMTCT services in the well-resourced setting of the capital city, Hanoi. Fifty-two HIV positive women enrolled in a self-help group in Hanoi were consulted, through in-depth interviews and bi-weekly meetings, about their experiences in accessing PMTCT services. Only 44% and 20% of the women had received minimal and comprehensive PMTCT services, respectively. Nine women did not receive any services. Twenty-two women received no counselling. The women reported being limited by lack of knowledge and information due to poor counselling, gaps in PMTCT services, and fear of stigma and discrimination. HIV testing was done too late for optimal interventions and poor quality of care by health staff was frequently mentioned. In a setting where PMTCT is available, HIV-infected women and children did not receive adequate care because of barriers to accessing those services. The results suggest key improvements would be improving quality of counselling and making PMTCT guidelines available to health services. Women should receive early HIV testing with adequate counselling, safe care and prophylaxis in a positive atmosphere towards HIV-infected women.

  8. Barriers to access prevention of mother-to-child transmission for HIV positive women in a well-resourced setting in Vietnam

    Directory of Open Access Journals (Sweden)

    Wright Pamela

    2008-04-01

    Full Text Available Abstract Background According to Vietnamese policy, HIV-infected women should have access at least to HIV testing and Nevirapine prophylaxis, or where available, to adequate counselling, HIV infection staging, ARV prophylaxis, and infant formula. Many studies in high HIV prevalence settings have reported low coverage of PMTCT services, but there have been few reports from low HIV prevalence settings, such as Asian countries. We investigated the access of HIV-infected pregnant women to PMTCT services in the well-resourced setting of the capital city, Hanoi. Methods Fifty-two HIV positive women enrolled in a self-help group in Hanoi were consulted, through in-depth interviews and bi-weekly meetings, about their experiences in accessing PMTCT services. Results Only 44% and 20% of the women had received minimal and comprehensive PMTCT services, respectively. Nine women did not receive any services. Twenty-two women received no counselling. The women reported being limited by lack of knowledge and information due to poor counselling, gaps in PMTCT services, and fear of stigma and discrimination. HIV testing was done too late for optimal interventions and poor quality of care by health staff was frequently mentioned. Conclusion In a setting where PMTCT is available, HIV-infected women and children did not receive adequate care because of barriers to accessing those services. The results suggest key improvements would be improving quality of counselling and making PMTCT guidelines available to health services. Women should receive early HIV testing with adequate counselling, safe care and prophylaxis in a positive atmosphere towards HIV-infected women.

  9. Methicillin Resistant Staphylococcus aureus Transmission in a Ghanaian Burn Unit : The Importance of Active Surveillance in Resource-Limited Settings

    NARCIS (Netherlands)

    Amissah, Nana Ama; Buultjens, Andrew H.; Ablordey, Anthony; van Dam, Lieke; Opoku-Ware, Ampomah; Baines, Sarah L.; Bulach, Dieter; Tetteh, Caitlin S.; Prah, Isaac; van der Werf, Tjip S.; Friedrich, Alexander W.; Seemann, Torsten; van Dijl, Jan Maarten; Stienstra, Ymkje; Stinear, Timothy P.; Rossen, John W.

    2017-01-01

    . Objectives: Staphylococcus aureus infections in burn patients can lead to serious complications and death. The frequency of S. aureus infection is high in low-and middle-income countries presumably due to limited resources, misuse of antibiotics and poor infection control. The objective of the

  10. Navigating Language Barriers: A Systematic Review of Patient Navigators' Impact on Cancer Screening for Limited English Proficient Patients.

    Science.gov (United States)

    Genoff, Margaux C; Zaballa, Alexandra; Gany, Francesca; Gonzalez, Javier; Ramirez, Julia; Jewell, Sarah T; Diamond, Lisa C

    2016-04-01

    To systematically review the literature on the impact of patient navigators on cancer screening for limited English proficient (LEP) patients. Electronic databases (PubMed, PsycINFO via OVID, Web of Science, Cochrane, EMBASE, and Scopus) through 8 May 2015. Articles in this review had: (1) a study population of LEP patients eligible for breast, cervical or colorectal cancer screenings, (2) a patient navigator intervention to provide services prior to or during cancer screening, (3) a comparison of the patient navigator intervention to either a control group or another intervention, and (4) language-specific outcomes related to the patient navigator intervention. We assessed the quality of the articles using the Downs and Black Scale. Fifteen studies met the inclusion criteria and evaluated the screening rates for breast, colorectal, and cervical cancer in 15 language populations. Fourteen studies resulted in improved screening rates for LEP patients between 7 and 60%. There was great variability in the patient navigation interventions evaluated. Training received by navigators was not reported in nine of the studies and no studies assessed the language skills of the patient navigators in English or the target language. This study is limited by the variability in study designs and limited reporting on patient navigator interventions, which reduces the ability to draw conclusions on the full effect of patient navigators. Overall, we found evidence that navigators improved screening rates for breast, cervical and colorectal cancer screening for LEP patients. Future studies should systematically collect data on the training curricula for navigators and assess their English and non-English language skills in order to identify ways to reduce disparities for LEP patients.

  11. Potential for Zika virus introduction and transmission in resource-limited countries in Africa and the Asia-Pacific region: a modelling study.

    Science.gov (United States)

    Bogoch, Isaac I; Brady, Oliver J; Kraemer, Moritz U G; German, Matthew; Creatore, Maria I; Brent, Shannon; Watts, Alexander G; Hay, Simon I; Kulkarni, Manisha A; Brownstein, John S; Khan, Kamran

    2016-11-01

    As the epidemic of Zika virus expands in the Americas, countries across Africa and the Asia-Pacific region are becoming increasingly susceptible to the importation and possible local spread of the virus. To support public health readiness, we aim to identify regions and times where the potential health, economic, and social effects from Zika virus are greatest, focusing on resource-limited countries in Africa and the Asia-Pacific region. Our model combined transportation network analysis, ecological modelling of mosquito occurrences, and vector competence for flavivirus transmission, using data from the International Air Transport Association, entomological observations from Zika's primary vector species, and climate conditions using WorldClim. We overlaid monthly flows of airline travellers arriving to Africa and the Asia-Pacific region from areas of the Americas suitable for year-round transmission of Zika virus with monthly maps of climatic suitability for mosquito-borne transmission of Zika virus within Africa and the Asia-Pacific region. An estimated 2·6 billion people live in areas of Africa and the Asia-Pacific region where the presence of competent mosquito vectors and suitable climatic conditions could support local transmission of Zika virus. Countries with large volumes of travellers arriving from Zika virus-affected areas of the Americas and large populations at risk of mosquito-borne Zika virus infection include India (67 422 travellers arriving per year; 1·2 billion residents in potential Zika transmission areas), China (238 415 travellers; 242 million residents), Indonesia (13 865 travellers; 197 million residents), Philippines (35 635 travellers; 70 million residents), and Thailand (29 241 travellers; 59 million residents). Many countries across Africa and the Asia-Pacific region are vulnerable to Zika virus. Strategic use of available health and human resources is essential to prevent or mitigate the health, economic, and social

  12. Analysis and control of the effects of over excitation limiters on the stability of the Itaipu HVAC transmission system

    Energy Technology Data Exchange (ETDEWEB)

    Jardim, J.L.; Macedo, N.J.; Santo, S.E.; Praca, A.S. [FURNAS Centrais Eletricas S.A., Rio de Janeiro, RJ (Brazil)

    1994-12-31

    The effect of over excitation limiters on power system voltage stability is presented in this paper. A linear analysis based on system eigenvalues for various operating conditions shows that voltage collapse is essentially a dynamic phenomenon. Time simulations using digital tools and real-time simulator were performed to verify lin ear results and study large disturbances. A control system designed to keep system in secure region is proposed. (author) 3 refs., 9 figs.

  13. Regulatory and cost barriers are likely to limit biosimilar development and expected savings in the near future.

    Science.gov (United States)

    Grabowski, Henry G; Guha, Rahul; Salgado, Maria

    2014-06-01

    In March 2010 Congress established an abbreviated Food and Drug Administration approval pathway for biosimilars-drugs that are very similar but not identical to a reference biological product and cost less. Because bringing biosimilars to the market currently requires large investments of money, fewer biosimilars are expected to enter the biologics market than has been the case with generic drugs entering the small-molecule drug market. Additionally, given the high regulatory hurdles to obtaining interchangeability-which would allow pharmacists to substitute a biosimilar for its reference product, subject to evolving state substitution laws-most biosimilars will likely compete as therapeutic alternatives instead of as therapeutic equivalents. In other words, biosimilars will need to compete with their reference product on the basis of quality; price; and manufacturer's reputation with physicians, insurers, and patient groups. Biosimilars also will face dynamic competition from new biologics in the same therapeutic class-including "biobetters," which offer incremental improvements on reference products, such as extended duration of action. The prospects for significant cost savings from the use of biosimilars appear to be limited for the next several years, but their use should increase over time because of both demand- and supply-side factors. Project HOPE—The People-to-People Health Foundation, Inc.

  14. Gas Pipelines, LP and LNG, Gas transmission line work provided to AIMS from Kansas Gas Service. Data is limited to CUE (Collaborative Utility Exchange) Participants and subcontractors of them., Published in 2004, Johnson County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Gas Pipelines, LP and LNG dataset current as of 2004. Gas transmission line work provided to AIMS from Kansas Gas Service. Data is limited to CUE (Collaborative...

  15. [Basic research on BSE transmission to people].

    Science.gov (United States)

    Bodemer, W; Kaup, F J

    2002-08-01

    Prion diseases of animal and man belong to neurological diseases with amyloidal deposition of the respective proteins. As to prion disease, the cellular prionprotein is in its abnormal isoform(s) an essential component of prionprotein aggregates found in affected tissue. In contrast to all neurodegenerative diseases like Morbus Alzheimer or Huntington's disease, prion diseases are transmissible. Therefore, prion diseases were designated Transmissible Spongiform Encephalopathies (TSE). The diseases are well known since decades. Scrapie was first described around 1750, a BSE case was reported in the 1850, most likely a misdiagnosis, and in 1920/1930 the human Creutzfeldt-Jakob disease (CJD) had been described. Transmission of CJD i.e. Kuru had been suspected in the early 1950s and erronously classified as slow virus disease. The CJD transmission posed a problem to humans when transplants from CJD cases were used for treatment. Fortunately, these iatrogenic transmissions remained limited. But with the advent of BSE and appearance of variant CJD cases in the UK and some places in Europe scientists suspected that transmission from cattle to man could have happened. From animal models we know of successful transmission via several routes. Species barriers do not completely prevent transmission. Rather transmission barriers might exist controlling individual susceptibility against prions. Modes of transmission, susceptibility for transmission, identification of receptor molecules as well as molecular mechanisms of the transmission process are intensely investigated. Current knowledge let us to assume that inapparent stages of prion infection pretend a (not existing) species barrier. This inapparent infection preceeds overt disease and, thus, most re-search focuses on the development of highly sensitive assay systems for detection of minute amounts of pathological prionprotein in suspected cases. Inapparence also should warn us to underestimate BSE or human vCJD cases; at

  16. A Qualitative Study of Barriers to Effectiveness of Interventions to Prevent Mother-to-Child Transmission of HIV in Arba Minch, Ethiopia

    Directory of Open Access Journals (Sweden)

    Adebola Adedimeji

    2012-01-01

    Full Text Available Objectives. Despite the availability of services to prevent mother-to-child transmission (PMTCT of HIV, socio-cultural, health system and operational factors constrain many pregnant women from accessing services or returning for followup thereby increasing the risk of vertical transmission of HIV to newborns. We highlight and describe unique contextual factors contributing to low utilization of PMTCT services in Arba-Minch, Ethiopia. Methods. Qualitative research design was utilized to obtain data through focus group discussions and in-depth interviews with antenatal clinic attendees, health workers health facilities in the study area. Results. Awareness of PMTCT services and knowledge of its benefits was nearly universal, although socioeconomic, cultural and health system factors, including stigma and desire to prevent knowledge of serostatus, impede access to and utilization of services. Health system factors—lack of appropriate followup mechanisms, inadequate access to ARV drugs and poorly equipped manpower also contribute to low utilization of services. Conclusion. Reducing mother-to-child transmission of HIV in sub-Saharan Africa will be more effective when unique contextual factors are identified and addressed. Effectiveness of PMTCT interventions rests on a well functioning health system that recognize the importance of social, economic, cultural contexts that HIV positive pregnant women live in.

  17. Impact of sea-level rise on cross-shore sediment transport on fetch-limited barrier reef island beaches under modal and cyclonic conditions.

    Science.gov (United States)

    Baldock, T E; Golshani, A; Atkinson, A; Shimamoto, T; Wu, S; Callaghan, D P; Mumby, P J

    2015-08-15

    A one-dimensional wave model is combined with an analytical sediment transport model to investigate the likely influence of sea-level rise on net cross-shore sediment transport on fetch-limited barrier reef and lagoon island beaches. The modelling considers if changes in the nearshore wave height and wave period in the lagoon induced by different water levels over the reef flat are likely to lead to net offshore or onshore movement of sediment. The results indicate that the effects of SLR on net sediment movement are highly variable and controlled by the bathymetry of the reef and lagoon. A significant range of reef-lagoon bathymetry, and notably shallow and narrow reefs, appears to lead hydrodynamic conditions and beaches that are likely to be stable or even accrete under SLR. Loss of reef structural complexity, particularly on the reef flat, increases the chance of sediment transport away from beaches and offshore. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Cost effectiveness of option B plus for prevention of mother-to-child transmission of HIV in resource-limited countries: evidence from Kumasi, Ghana.

    Science.gov (United States)

    VanDeusen, Adam; Paintsil, Elijah; Agyarko-Poku, Thomas; Long, Elisa F

    2015-03-18

    Achieving the goal of eliminating mother-to-child HIV transmission (MTCT) necessitates increased access to antiretroviral therapy (ART) for HIV-infected pregnant women. Option B provides ART through pregnancy and breastfeeding, whereas Option B+ recommends continuous ART regardless of CD4 count, thus potentially reducing MTCT during future pregnancies. Our objective was to compare maternal and pediatric health outcomes and cost-effectiveness of Option B+ versus Option B in Ghana. A decision-analytic model was developed to simulate HIV progression in mothers and transmission (in utero, during birth, or through breastfeeding) to current and all future children. Clinical parameters, including antenatal care access and fertility rates, were estimated from a retrospective review of 817 medical records at two hospitals in Ghana. Additional parameters were obtained from published literature. Modeled outcomes include HIV infections averted among newborn children, quality-adjusted life-years (QALYs), and cost-effectiveness ratios. HIV-infected women in Ghana have a lifetime average of 2.3 children (SD 1.3). Projected maternal life expectancy under Option B+ is 16.1 years, versus 16.0 years with Option B, yielding a gain of 0.1 maternal QALYs and 3.2 additional QALYs per child. Despite higher initial ART costs, Option B+ costs $785/QALY gained, a value considered very cost-effective by World Health Organization benchmarks. Widespread implementation of Option B+ in Ghana could theoretically prevent up to 668 HIV infections among children annually. Cost-effectiveness estimates remained favorable over robust sensitivity analyses. Although more expensive than Option B, Option B+ substantially reduces MTCT in future pregnancies, increases both maternal and pediatric QALYs, and is a cost-effective use of limited resources in Ghana.

  19. Multilayer moisture barrier

    Science.gov (United States)

    Pankow, Joel W; Jorgensen, Gary J; Terwilliger, Kent M; Glick, Stephen H; Isomaki, Nora; Harkonen, Kari; Turkulainen, Tommy

    2015-04-21

    A moisture barrier, device or product having a moisture barrier or a method of fabricating a moisture barrier having at least a polymer layer, and interfacial layer, and a barrier layer. The polymer layer may be fabricated from any suitable polymer including, but not limited to, fluoropolymers such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), or ethylene-tetrafluoroethylene (ETFE). The interfacial layer may be formed by atomic layer deposition (ALD). In embodiments featuring an ALD interfacial layer, the deposited interfacial substance may be, but is not limited to, Al.sub.2O.sub.3, AlSiO.sub.x, TiO.sub.2, and an Al.sub.2O.sub.3/TiO.sub.2 laminate. The barrier layer associated with the interfacial layer may be deposited by plasma enhanced chemical vapor deposition (PECVD). The barrier layer may be a SiO.sub.xN.sub.y film.

  20. Identifying Barriers, Perceptions and Motivations Related to Healthy Eating and Physical Activity among 6th to 8th Grade, Rural, Limited-Resource Adolescents

    Science.gov (United States)

    Kumar, Janavi; Adhikari, Koushik; Li, Yijing; Lindshield, Erika; Muturi, Nancy; Kidd, Tandalayo

    2016-01-01

    Purpose: The purpose of this paper is to enable community members to discuss their perceptions of eating habits and physical activity in relation to sixth, seventh, and eighth graders, and reveal facilitators and barriers to healthy eating behavior and physical activity engagement. Design/methodology/approach: Nine focus groups, which included six…

  1. Omnidirectional ventilated acoustic barrier

    Science.gov (United States)

    Zhang, Hai-long; Zhu, Yi-fan; Liang, Bin; Yang, Jing; Yang, Jun; Cheng, Jian-chun

    2017-11-01

    As an important problem in acoustics, sound insulation finds applications in a great variety of situations. In the existing schemes, however, there has always been a trade-off between the thinness of sound-insulating devices and their ventilating capabilities, limiting their potentials in the control of low-frequency sound in high ventilation environments. Here, we design and experimentally implement an omnidirectional acoustic barrier with a planar profile, subwavelength thickness ( 0.18 λ ), yet high ventilation. The proposed mechanism is based on the interference between the resonant scattering of discrete states and the background scattering of continuous states which induces a Fano-like asymmetric transmission profile. Benefitting from the binary-structured design of the coiled unit and hollow pipe, it maximally simplifies the design and fabrication while ensuring the ventilation for all the non-resonant units with open tubes. The simulated and measured results agree well, showing the effectiveness of our proposed mechanism to block low frequency sound coming from various directions while allowing 63% of the air flow to pass. We anticipate our design to open routes to design sound insulators and to enable applications in traditionally unattainable cases such as those calling for noise reduction and cooling simultaneously.

  2. Building barriers.

    Science.gov (United States)

    Turksen, Kursad

    2017-10-02

    Formation of tissue barriers starts in early development where it is critical for normal cell fate selection, differentiation and organogenesis. Barrier maintenance is critical to the ongoing function of organs during adulthood and aging. Dysfunctional tissue barrier formation and function at any stage of the organismal life cycle underlies many disease states.

  3. Fish oil improves motor function, limits blood-brain barrier disruption, and reduces Mmp9 gene expression in a rat model of juvenile traumatic brain injury.

    Science.gov (United States)

    Russell, K L; Berman, N E J; Gregg, P R A; Levant, B

    2014-01-01

    The effects of an oral fish oil treatment regimen on sensorimotor, blood-brain barrier, and biochemical outcomes of traumatic brain injury (TBI) were investigated in a juvenile rat model. Seventeen-day old Long-Evans rats were given a 15mL/kg fish oil (2.01g/kg EPA, 1.34g/kg DHA) or soybean oil dose via oral gavage 30min prior to being subjected to a controlled cortical impact injury or sham surgery, followed by daily doses for seven days. Fish oil treatment resulted in less severe hindlimb deficits after TBI as assessed with the beam walk test, decreased cerebral IgG infiltration, and decreased TBI-induced expression of the Mmp9 gene one day after injury. These results indicate that fish oil improved functional outcome after TBI resulting, at least in part from decreased disruption of the blood-brain barrier through a mechanism that includes attenuation of TBI-induced expression of Mmp9. © 2013 Elsevier Ltd. All rights reserved.

  4. Protective barrier development: Overview

    International Nuclear Information System (INIS)

    Wing, N.R.; Gee, G.W.

    1990-01-01

    Protective barrier and warning marker systems are being developed to isolate wastes disposed of near the earth's surface at the Hanford Site. The barrier is designed to function in an arid to semiarid climate, to limit infiltration and percolation of water through the waste zone to near-zero, to be maintenance free, and to last up to 10,000 yr. Natural materials (e.g., fine soil, sand, gravel, riprap, clay, asphalt) have been selected to optimize barrier performance and longevity and to create an integrated structure with redundant features. These materials isolate wastes by limiting water drainage; reducing the likelihood of plant, animal, and human intrusion; controlling emission of noxious gases; and minimizing erosion. Westinghouse Hanford Company and Pacific Northwest Laboratory efforts to assess the performance of various barrier and marker designs will be discussed

  5. Adiabatic heavy-ion fusion potentials for fusion at deep sub-barrier ...

    Indian Academy of Sciences (India)

    barrier energies has been examined. The adiabatic limit of fusion barriers has been determined from experimental data using the barrier penetration model. These adiabatic barriers are consistent with the adiabatic fusion barriers derived from ...

  6. Dual-polarization multi-band optical OFDM transmission and transceiver limitations for up to 500 Gb/s uncompensated long-haul links.

    Science.gov (United States)

    Giacoumidis, E; Jarajreh, M A; Sygletos, S; Le, S T; Farjady, F; Tsokanos, A; Hamié, A; Pincemin, E; Jaouën, Y; Ellis, A D; Doran, N J

    2014-05-05

    A number of critical issues for dual-polarization single- and multi-band optical orthogonal-frequency division multiplexing (DP-SB/MB-OFDM) signals are analyzed in dispersion compensation fiber (DCF)-free long-haul links. For the first time, different DP crosstalk removal techniques are compared, the maximum transmission-reach is investigated, and the impact of subcarrier number and high-level modulation formats are explored thoroughly. It is shown, for a bit-error-rate (BER) of 10(-3), 2000 km of quaternary phase-shift keying (QPSK) DP-MB-OFDM transmission is feasible. At high launched optical powers (LOP), maximum-likelihood decoding can extend the LOP of 40 Gb/s QPSK DP-SB-OFDM at 2000 km by 1.5 dB compared to zero-forcing. For a 100 Gb/s DP-MB-OFDM system, a high number of subcarriers contribute to improved BER but at the cost of digital signal processing computational complexity, whilst by adapting the cyclic prefix length the BER can be improved for a low number of subcarriers. In addition, when 16-quadrature amplitude modulation (16QAM) is employed the digital-to-analogue/analogue-to-digital converter (DAC/ADC) bandwidth is relaxed with a degraded BER; while the 'circular' 8QAM is slightly superior to its 'rectangular' form. Finally, the transmission of wavelength-division multiplexing DP-MB-OFDM and single-carrier DP-QPSK is experimentally compared for up to 500 Gb/s showing great potential and similar performance at 1000 km DCF-free G.652 line.

  7. Caregiver financial distress, depressive symptoms and limited social capital as barriers to children's dental care in a mid-western county in the United States.

    Science.gov (United States)

    Kruger, J S; Kodjebacheva, G D; Kunkel, L; Smith, K D; Kruger, D J

    2015-12-01

    To identify barriers to children's access to dental care. A cross-sectional health survey. All residential census tracts in Genesee County, Michigan, USA. 498 adults who reported having children in their households, extracted from 2,932 randomly selected adult participants in the 2009 and 2011 surveys. Stepwise logistic regression was used to predict two dependent variables: children's lack of any visits to dentists' offices and unmet dental care needs (defined as needing dental care but not receiving it due to cost) in the previous year as reported by the adults. Independent variables included gender, age, education, race/ethnicity, financial planning, financial distress, fear of crime, stress, depressive symptoms, experiences of discrimination, and neighbourhood social capital. Of the 498 adults, 29.9% reported that they had children who had not visited a dentist in the past 12 months and 13% reported that they had household children with unmet dental care needs in the past year. Adults who reported higher depressive symptoms, lower neighbourhood social capital, greater financial distress, and who were younger were more likely to have household children who did not visit a dentist in the past year. Financial distress was the only significant predictor when controlling for other variables to predict unmet dental care needs. Factors beyond financial distress affect children's dental care; these include parental depressive symptoms and lower neighbourhood social capital. Interventions promoting parental mental health and social integration may increase dental care among children.

  8. Joint Use of Adaptive Equalization and Cyclic Noise Cancellation for Band-Limited OQAM Based Multi-Carrier Transmission in Power-Line Communication Systems

    Science.gov (United States)

    Kunishima, Hiromitsu; Koga, Hisao; Muta, Osamu; Akaiwa, Yoshihiko

    Power-line communication (PLC) technique is one method to realize high-speed communications in a home network. In PLC channels, the transmission signal quality is degraded by colored non-Gaussian noise as well as frequency-selectivity of the channels. In this paper, we describe our investigation of the performance of a OQAM-MCT system in which a noise canceller is used jointly with a time-domain per-subcarrier adaptive equalizer. Furthermore, we propose a noise cancellation method designed for the OQAM-MCT system. The performance of the OQAM-MCT system is evaluated in PLC channels with measured impulse responses in the presence of measured noise. Computer simulation results show that the bit rate of the OQAM-MCT system is improved using both an adaptive equalizer and noise canceller, and that the OQAM-MCT system achieves better performance than an OFDM system with an insufficient length of the guard interval.

  9. The Cost of Transmission for Wind Energy: A Review of Transmission Planning Studies

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Andrew D.; Wiser, Ryan; Porter, Kevin

    2009-02-02

    The rapid development of wind power that the United States has experienced over the last several years has been coupled with a growing concern that wind development will require substantial additions to the nation's transmission infrastructure. Transmission is particularly important for wind power due to the locational dependence of wind resources, the relatively low capacity factor of wind plants, and the mismatch between the short lead time to build a new wind project and the longer lead time often needed to plan, permit, and construct transmission. It is clear that institutional issues related to transmission planning, siting, and cost allocation will pose major obstacles to accelerated wind power deployment, but also of concern is the potential cost of this infrastructure build out. Simply put, how much extra cost will society bear to deliver wind power to load centers? Without an answer to this question, there can be no consensus on whether or not the cost of developing transmission for wind will be a major barrier to further wind deployment, or whether the institutional barriers to transmission expansion are likely to be of more immediate concern. In this report, we review a sample of 40 detailed transmission studies that have included wind power. These studies cover a broad geographic area, and were completed from 2001-2008. Our primary goal in reviewing these studies is to develop a better understanding of the transmission costs needed to access growing quantities of wind generation. A secondary goal is to gain a better appreciation of the differences in transmission planning approaches in order to identify those methodologies that seem most able to estimate the incremental transmission costs associated with wind development. Finally, we hope that the resulting dataset and discussion might be used to inform the assumptions, methods, and results of higher-level assessment models that are sometimes used to estimate the cost of wind deployment (e.g. NEMS

  10. Novel control of grid connected photovoltaic (PV) solar farm for improving transient stability and stability and transmission limits both during night and day

    Energy Technology Data Exchange (ETDEWEB)

    Varma, Rajiv; Arifur Rahman, Shah; Seethapathy, Ravi

    2010-09-15

    This paper presents a novel control of a solar farm inverter to improve grid power transfer limits. In the night, when the solar farm is completely idle, this new control technique makes the solar farm inverter behave like a FACTS device. The solar farm inverter provides voltage regulation at the point of common coupling and improves the power transfer limits, significantly. During the day time also, when solar farm is producing real power, this new control strategy makes the solar farm inverter provide voltage control with the remaining inverter MVA capacity and thereby increases power transfer capacity substantially.

  11. Limited genetic diversity and purifying selection in Iranian Plasmodium falciparum Generative Cell Specific 1 (PfGCS1), a potential target for transmission-blocking vaccine.

    Science.gov (United States)

    Mehrizi, Akram Abouie; Zakeri, Sedigheh; Djadid, Navid Dinparast

    2014-03-01

    Among vaccines, those that have an impact on transmission are in priority for malaria elimination and eradication. One of the new identified transmission-blocking vaccine (TBV) candidate antigens is Generative Cell Specific 1 (GCS1) located on the male gametocytes of Plasmodium species. Since the antigenic diversity could hamper vaccine development, it is essential to determine the gene diversity of gcs1 in global malaria-endemic areas in order to develop efficient TBVs. Therefore, in this study, nucleotide diversity and selection in the Plasmodium falciparum GCS1 (PfGCS1) antigen were analyzed in 36 Iranian clinical isolates by using PCR sequencing in order to provide useful information on this TBV candidate antigen. For this purpose, successful sequence analysis was carried out in 36 isolates. The results showed three single-nucleotide polymorphisms including one synonymous (G1475A) and two non-synonymous (A697G and G1479A) mutations leading to 3 distinct haplotypes with different frequencies: GCS1-A (N184/D445, 16.7%), GCS1-B (S184/D445, 63.9%), and GCS1-C (N184/N445, 19.4%). The overall nucleotide diversity (π) for all 36 sequences of Iranian pfgcs1 was 0.00066±0.00012, and the dN-dS value (-0.00028) was negative, suggesting the possible action of purifying selection in this gene. Epitope mapping prediction of PfGCS1 antigen showed that most of the potential linear and conformational B-cell epitopes are located in conserved regions. However, N184S and D445N mutations were also involved in linear and conformational B-cell epitopes, respectively that should be considered in vaccine design. In conclusion, the present study showed a very low genetic diversity of pfgcs1 gene among Iranian isolates. Considering PfGCS1 as a conserved TBV candidate, our data provides valuable information to develop a PfGCS1-based TBV. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Infection Control Programs and Antibiotic Control Programs to Limit Transmission of Multi-Drug Resistant Acinetobacter baumannii Infections: Evolution of Old Problems and New Challenges for Institutes.

    Science.gov (United States)

    Chen, Chang-Hua; Lin, Li-Chen; Chang, Yu-Jun; Chen, Yu-Min; Chang, Chin-Yen; Huang, Chieh-Chen

    2015-07-30

    Acinetobacter baumannii complex (A. baumannii) has been isolated worldwide. The rapid spread of multidrug-resistant A. baumannii complex (MDRAB) in clinical settings has made choosing an appropriate antibiotic to treat these infections and executing contact precautions difficult for clinicians. Although controlling the transmission of MDRAB is a high priority for institutions, there is little information about MDRAB control. Therefore, this study evaluated infection control measures for A. baumannii infections, clusters and outbreaks in the literature. We performed a review of OVID Medline (from 1980 to 2015), and analyzed the literature. We propose that both infection control programs and antibiotic control programs are essential for control of MDRAB. The first, effective control of MDRAB infections, requires compliance with a series of infection control methods including strict environmental cleaning, effective sterilization of reusable medical equipment, concentration on proper hand hygiene practices, and use of contact precautions, together with appropriate administrative guidance. The second strategy, effective antibiotic control programs to decrease A. baumannii, is also of paramount importance. We believe that both infection control programs and antibiotics stewardship programs are essential for control of MDRAB infections.

  13. Quantitative X-ray Elemental Imaging in Plant Materials at the Subcellular Level with a Transmission Electron Microscope: Applications and Limitations

    Directory of Open Access Journals (Sweden)

    Shaoliang Chen

    2014-04-01

    Full Text Available Energy-dispersive X-ray microanalysis (EDX is a technique for determining the distribution of elements in various materials. Here, we report a protocol for high-spatial-resolution X-ray elemental imaging and quantification in plant tissues at subcellular levels with a scanning transmission electron microscope (STEM. Calibration standards were established by producing agar blocks loaded with increasing KCl or NaCl concentrations. TEM-EDX images showed that the salts were evenly distributed in the agar matrix, but tended to aggregate at high concentrations. The mean intensities of K+, Cl−, and Na+ derived from elemental images were linearly correlated to the concentrations of these elements in the agar, over the entire concentration range tested (R > 0.916. We applied this method to plant root tissues. X-ray images were acquired at an actual resolution of 50 nm ´ 50 nm to 100 nm ´ 100 nm. We found that cell walls exhibited higher elemental concentrations than vacuoles. Plants exposed to salt stress showed dramatic accumulation of Na+ and Cl− in the transport tissues, and reached levels similar to those applied in the external solution (300 mM. The advantage of TEM-EDX mapping was the high-spatial-resolution achieved for imaging elemental distributions in a particular area with simultaneous quantitative analyses of multiple target elements.

  14. Epidemiological Outbreaks of Pneumocystis jirovecii Pneumonia Are Not Limited to Kidney Transplant Recipients: Genotyping Confirms Common Source of Transmission in a Liver Transplantation Unit.

    Science.gov (United States)

    Desoubeaux, Guillaume; Dominique, Manon; Morio, Florent; Thepault, Rose-Anne; Franck-Martel, Claire; Tellier, Anne-Charlotte; Ferrandière, Martine; Hennequin, Christophe; Bernard, Louis; Salamé, Ephrem; Bailly, Éric; Chandenier, Jacques

    2016-05-01

    Over a 5-month period, four liver transplant patients at a single hospital were diagnosed with Pneumocystis jirovecii pneumonia (PCP). This unusually high incidence was investigated using molecular genotyping. Bronchoalveolar lavage fluids (BALF) obtained from the four liver recipients diagnosed with PCP were processed for multilocus sequence typing (MLST) at three loci (SOD, mt26s, and CYB). Twenty-four other BALF samples, which were positive for P. jirovecii and collected from 24 epidemiologically unrelated patients with clinical signs of PCP, were studied in parallel by use of the same method. Pneumocystis jirovecii isolates from the four liver recipients all had the same genotype, which was different from those of the isolates from all the epidemiologically unrelated individuals studied. These findings supported the hypothesis of a common source of contamination or even cross-transmission of a single P. jirovecii clone between the four liver recipients. Hospitalization mapping showed several possible encounters between these four patients, including outpatient consultations on one particular date when they all possibly met. This study demonstrates the value of molecular genotyping of P. jirovecii isolated from clinical samples for epidemiological investigation of PCP outbreaks. It is also the first description of a common source of exposure to a single P. jirovecii clone between liver transplant recipients and highlights the importance of prophylaxis in such a population. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  15. Transmission issues

    International Nuclear Information System (INIS)

    Bradford, J.; Wilson, L.; Thon, S.; Millar, N.

    2005-01-01

    This session on transmission issues focused on the role that transmission plays in electricity markets and the importance of getting the market structure right in terms of generation divestiture with buy back contracts, demand side responsive programs, transmission upgrades and long term contracts. The difficulties of distinguishing between market power and scarcity were examined along with some of the complications that ensue if transmission experiences congestion, as exemplified by the August 2003 blackout in eastern North America. The presentations described the best ways to handle transmission issues, and debated whether transmission should be deregulated or follow market forces. Issues of interconnections and reliability of connections were also debated along with the attempt to integrate renewables into the grid. Some presentations identified what new transmission must be built and what must be done to ensure that transmission gets built. The challenges and business opportunities for transmission in Alberta were discussed with reference to plans to invest in new infrastructure, where it is going outside of the province and how it works with other jurisdictions. Manitoba's Conawapa Hydro Project and its 2000 MW tie line to Ontario was also discussed. Some examples of non-optimal use of interconnections in Europe were also discussed in an effort to learn from these mistakes and avoid them in Canada. tabs., figs

  16. Efficient transmission and characterization of creutzfeldt-jakob disease strains in bank voles.

    Directory of Open Access Journals (Sweden)

    2006-02-01

    Full Text Available Transmission of prions between species is limited by the "species barrier," which hampers a full characterization of human prion strains in the mouse model. We report that the efficiency of primary transmission of prions from Creutzfeldt-Jakob disease patients to a wild rodent species, the bank vole (Clethrionomys glareolus, is comparable to that reported in transgenic mice carrying human prion protein, in spite of a low prion protein-sequence homology between man and vole. Voles infected with sporadic and genetic Creutzfeldt-Jakob disease isolates show strain-specific patterns of spongiform degeneration and pathological prion protein-deposition, and accumulate protease-resistant prion protein with biochemical properties similar to the human counterpart. Adaptation of genetic Creutzfeldt-Jakob disease isolates to voles shows little or no evidence of a transmission barrier, in contrast to the striking barriers observed during transmission of mouse, hamster, and sheep prions to voles. Our results imply that in voles there is no clear relationship between the degree of homology of the prion protein of the donor and recipient species and susceptibility, consistent with the view that the prion strain gives a major contribution to the species barrier. The vole is therefore a valuable model to study human prion diversity and, being susceptible to a range of animal prions, represents a unique tool for comparing isolates from different species.

  17. Efficient Transmission and Characterization of Creutzfeldt–Jakob Disease Strains in Bank Voles

    Science.gov (United States)

    Nonno, Romolo; Bari, Michele A. Di; Cardone, Franco; Vaccari, Gabriele; Fazzi, Paola; Dell'Omo, Giacomo; Cartoni, Claudia; Ingrosso, Loredana; Boyle, Aileen; Galeno, Roberta; Sbriccoli, Marco; Lipp, Hans-Peter; Bruce, Moira; Pocchiari, Maurizio; Agrimi, Umberto

    2006-01-01

    Transmission of prions between species is limited by the “species barrier,” which hampers a full characterization of human prion strains in the mouse model. We report that the efficiency of primary transmission of prions from Creutzfeldt–Jakob disease patients to a wild rodent species, the bank vole (Clethrionomys glareolus), is comparable to that reported in transgenic mice carrying human prion protein, in spite of a low prion protein–sequence homology between man and vole. Voles infected with sporadic and genetic Creutzfeldt–Jakob disease isolates show strain-specific patterns of spongiform degeneration and pathological prion protein–deposition, and accumulate protease-resistant prion protein with biochemical properties similar to the human counterpart. Adaptation of genetic Creutzfeldt–Jakob disease isolates to voles shows little or no evidence of a transmission barrier, in contrast to the striking barriers observed during transmission of mouse, hamster, and sheep prions to voles. Our results imply that in voles there is no clear relationship between the degree of homology of the prion protein of the donor and recipient species and susceptibility, consistent with the view that the prion strain gives a major contribution to the species barrier. The vole is therefore a valuable model to study human prion diversity and, being susceptible to a range of animal prions, represents a unique tool for comparing isolates from different species. PMID:16518470

  18. Efficient transmission and characterization of Creutzfeldt-Jakob disease strains in bank voles.

    Directory of Open Access Journals (Sweden)

    Romolo Nonno

    2006-02-01

    Full Text Available Transmission of prions between species is limited by the "species barrier," which hampers a full characterization of human prion strains in the mouse model. We report that the efficiency of primary transmission of prions from Creutzfeldt-Jakob disease patients to a wild rodent species, the bank vole (Clethrionomys glareolus, is comparable to that reported in transgenic mice carrying human prion protein, in spite of a low prion protein-sequence homology between man and vole. Voles infected with sporadic and genetic Creutzfeldt-Jakob disease isolates show strain-specific patterns of spongiform degeneration and pathological prion protein-deposition, and accumulate protease-resistant prion protein with biochemical properties similar to the human counterpart. Adaptation of genetic Creutzfeldt-Jakob disease isolates to voles shows little or no evidence of a transmission barrier, in contrast to the striking barriers observed during transmission of mouse, hamster, and sheep prions to voles. Our results imply that in voles there is no clear relationship between the degree of homology of the prion protein of the donor and recipient species and susceptibility, consistent with the view that the prion strain gives a major contribution to the species barrier. The vole is therefore a valuable model to study human prion diversity and, being susceptible to a range of animal prions, represents a unique tool for comparing isolates from different species.

  19. DEM Modeling of a Flexible Barrier Impacted by a Dry Granular Flow

    Science.gov (United States)

    Albaba, Adel; Lambert, Stéphane; Kneib, François; Chareyre, Bruno; Nicot, François

    2017-11-01

    Flexible barriers are widely used as protection structures against natural hazards in mountainous regions, in particular for containing granular materials such as debris flows, snow avalanches and rock slides. This article presents a discrete element method-based model developed in the aim of investigating the response of flexible barriers in such contexts. It allows for accounting for the peculiar mechanical and geometrical characteristics of both the granular flow and the barrier in a same framework, and with limited assumptions. The model, developed with YADE software, is described in detail, as well as its calibration. In particular, cables are modeled as continuous bodies. Besides, it naturally considers the sliding of rings along supporting cables. The model is then applied for a generic flexible barrier to demonstrate its capacities in accounting for the behavior of different components. A detailed analysis of the forces in the different components showed that energy dissipators (ED) had limited influence on total force applied to the barrier and retaining capacity, but greatly influenced the load transmission within the barrier and the force in anchors. A sensitivity analysis showed that the barrier's response significantly changes according to the choice of ED activation force and incoming flow conditions.

  20. Quantifying Transmission.

    Science.gov (United States)

    Woolhouse, Mark

    2017-07-01

    Transmissibility is the defining characteristic of infectious diseases. Quantifying transmission matters for understanding infectious disease epidemiology and designing evidence-based disease control programs. Tracing individual transmission events can be achieved by epidemiological investigation coupled with pathogen typing or genome sequencing. Individual infectiousness can be estimated by measuring pathogen loads, but few studies have directly estimated the ability of infected hosts to transmit to uninfected hosts. Individuals' opportunities to transmit infection are dependent on behavioral and other risk factors relevant given the transmission route of the pathogen concerned. Transmission at the population level can be quantified through knowledge of risk factors in the population or phylogeographic analysis of pathogen sequence data. Mathematical model-based approaches require estimation of the per capita transmission rate and basic reproduction number, obtained by fitting models to case data and/or analysis of pathogen sequence data. Heterogeneities in infectiousness, contact behavior, and susceptibility can have substantial effects on the epidemiology of an infectious disease, so estimates of only mean values may be insufficient. For some pathogens, super-shedders (infected individuals who are highly infectious) and super-spreaders (individuals with more opportunities to transmit infection) may be important. Future work on quantifying transmission should involve integrated analyses of multiple data sources.

  1. Limites politiques et barrières sociales dans le monde maya classique Political Limits and Social Barriers in the Classic Maya World: Reflections Based on a Few Archaeological Experiences

    Directory of Open Access Journals (Sweden)

    Dominique Michelet

    2012-12-01

    Full Text Available L’archéologie des Basses Terres mayas à l’époque classique est riche de données susceptibles de nous renseigner sur plusieurs types de « frontières » sociopolitiques. Si la question des limites territoriales des entités politiques du monde classique constitue, depuis les années 1970, un objectif tout à fait conscient de la recherche, bien d’autres éléments des partitionnements sociopolitiques existent, mais ils n’ont pas reçu, le plus souvent, l’attention qu’ils méritent. L’examen de quelques informations, empruntées aux résultats de projets de recherche collective récents, indique que les démarcations formelles plus ou moins minces durent être rares, qu’il y aurait même eu peu de bornages explicites et que les seuils étaient dotés d’une épaisseur certaine, leur franchissement obéissant à des codes précis et/ou impliquant des comportements ritualisés.The archaeology of the Maya Lowlands of the classical era is rich in data that are likely to have something to teach us about several types of sociopolitical “boundary”. Although research since the 1970s has consciously aimed to address the question of the territorial limits of classical-world political entities, many other elements of sociopolitical partitioning exist, but they have tended not to receive the attention they deserve. The examination of a few pieces of information, borrowed from the results of recent collective research projects, indicates that more-or-less thin formal demarcations must have been rare, that there would even have been few explicit boundary markings, and that the thresholds were endowed with a certain thickness, their crossing obeying precise codes and/or involving ritualised behaviours.

  2. Simulating Global AeroMACS Airport Ground Station Antenna Power Transmission Limits to Avoid Interference With Mobile Satellite Service Feeder Uplinks

    Science.gov (United States)

    Wilson, Jeffrey D.

    2013-01-01

    The Aeronautical Mobile Airport Communications System (AeroMACS), which is based upon the IEEE 802.16e mobile wireless standard, is expected to be implemented in the 5091 to 5150 MHz frequency band. As this band is also occupied by Mobile Satellite Service feeder uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference are under analysis in order to enable the definition of standards that assure that such interference will be avoided. In this study, the cumulative interference power distribution at low Earth orbit from transmitters at global airports was simulated with the Visualyse Professional software. The dependence of the interference power on antenna distribution, gain patterns, duty cycle, and antenna tilt was simulated. As a function of these parameters, the simulation results are presented in terms of the limitations on transmitter power from global airports required to maintain the cumulative interference power under the established threshold.

  3. Barrier Systems

    NARCIS (Netherlands)

    Heteren, S. van

    2015-01-01

    Barrier-system dynamics are a function of antecedent topography and substrate lithology, Relative sea-level (RSL) changes, sediment availability and type, climate, vegetation type and cover, and various aero- and hydrodynamic processes during fair-weather conditions and extreme events. Global change

  4. Data transmission

    National Research Council Canada - National Science Library

    Tugal, Dogan A; Tugal, Osman

    1989-01-01

    This updated second edition provides working answers to today's critical questions about designing and managing all types of data transmission systems and features a new chapter on local area networks (LANs...

  5. Shingles Transmission

    Science.gov (United States)

    ... Search Form Controls Cancel Submit Search The CDC Shingles (Herpes Zoster) Note: Javascript is disabled or is ... message, please visit this page: About CDC.gov . Shingles Home About Shingles Overview Signs & Symptoms Transmission Complications ...

  6. HIV Transmission

    Science.gov (United States)

    ... Abroad Treatment Basic Statistics Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... on HIV Syndicated Content Website Feedback HIV/AIDS HIV Transmission Language: English (US) Español (Spanish) Recommend on ...

  7. Seeded fibrillation as molecular basis of the species barrier in human prion diseases.

    Directory of Open Access Journals (Sweden)

    Lars Luers

    Full Text Available Prion diseases are transmissible spongiform encephalopathies in humans and animals, including scrapie in sheep, bovine spongiform encephalopathy (BSE in cattle, chronic wasting disease (CWD in deer, and Creutzfeldt-Jakob disease (CJD in humans. The hallmark of prion diseases is the conversion of the host-encoded prion protein (PrP(C to its pathological isoform PrP(Sc, which is accompanied by PrP fibrillation. Transmission is not restricted within one species, but can also occur between species. In some cases a species barrier can be observed that results in limited or unsuccessful transmission. The mechanism behind interspecies transmissibility or species barriers is not completely understood. To analyse this process at a molecular level, we previously established an in vitro fibrillation assay, in which recombinant PrP (recPrP as substrate can be specifically seeded by PrP(Sc as seed. Seeding with purified components, with no additional cellular components, is a direct consequence of the "prion-protein-only" hypothesis. We therefore hypothesise, that the species barrier is based on the interaction of PrP(C and PrP(Sc. Whereas in our earlier studies, the interspecies transmission in animal systems was analysed, the focus of this study lies on the transmission from animals to humans. We therefore combined seeds from species cattle, sheep and deer (BSE, scrapie, CWD with human recPrP. Homologous seeding served as a control. Our results are consistent with epidemiology, other in vitro aggregation studies, and bioassays investigating the transmission between humans, cattle, sheep, and deer. In contrast to CJD and BSE seeds, which show a seeding activity we can demonstrate a species barrier for seeds from scrapie and CWD in vitro. We could show that the seeding activity and therewith the molecular interaction of PrP as substrate and PrP(Sc as seed is sufficient to explain the phenomenon of species barriers. Therefore our data supports the hypothesis

  8. Transmission of Information: An Overview.

    Science.gov (United States)

    Thoma, George R.

    1981-01-01

    Outlines the basic principles underlying the transmission of information, including analog and digital modulation, limitations to communications, configurations of communications networks, optical fiber cables, and earth satellites. Six references are cited. (FM)

  9. Patient advocacy: barriers and facilitators

    OpenAIRE

    Nikravesh Mansoure; Ahmadi Fazlollah; Oskouie Fatemeh; Negarandeh Reza; Hallberg Ingalill

    2006-01-01

    Abstract Background During the two recent decades, advocacy has been a topic of much debate in the nursing profession. Although advocacy has embraced a crucial role for nurses, its extent is often limited in practice. While a variety of studies have been generated all over the world, barriers and facilitators in the patient advocacy have not been completely identified. This article presents the findings of a study exploring the barriers and facilitators influencing the role of advocacy among ...

  10. Transmission Lines or Poles, Electric, Electric transmission lines locations provided to us from Kansas City Power and Light and City of Gardner only at this time. AIMS is working on getting other providers in area. Data is limited to CUE (Collaborative Utility Exchange) Participants and subc, Published in 2004, Johnson County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Transmission Lines or Poles, Electric dataset current as of 2004. Electric transmission lines locations provided to us from Kansas City Power and Light and City of...

  11. Technology of optical azimuth transmission

    Science.gov (United States)

    Lu, Honggang; Hu, Chunsheng; Wang, Xingshu; Gao, Yang

    2012-11-01

    It often needs transfer a reference from one place to another place in aerospace and guided missile launching. At first, principles of several typical optical azimuth transmission methods are presented. Several typical methods are introduced, such as Theodolite (including gyro-theodolite) collimation method, Camera series method, Optical apparatus for azimuth method and polarization modulated light transmission method. For these typical azimuth transmission methods, their essential theories are elaborated. Then the devices, the application fields and limitations of these typical methods' are presented. Theodolite (including gyro-theodolite) collimation method is used in the ground assembly of spacecraft. Camera series method and optical apparatus for azimuth method are used in azimuth transmission between different decks of ship. Polarization modulated light transmission method is used in azimuth transmission of rocket and guided missile. At the last, the further developments of these methods are discussed.

  12. Market and Policy Barriers to Energy Storage Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Bhatnagar, Dhruv [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Currier, Aileen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez, Jacquelynne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ma, Ookie [Dept. of Energy (DOE), Washington DC (United States) Office of Energy Efficiency and Renewable Energy; Kirby, Brendan [Consultant

    2013-09-01

    Electric energy storage technologies can provide numerous grid services; there are a number of factors that restrict their current deployment. The most significant barrier to deployment is high capital costs, though several recent deployments indicate that capital costs are decreasing and energy storage may be the preferred economic alternative in certain situations. However, a number of other market and regulatory barriers persist, limiting further deployment. These barriers can be categorized into regulatory barriers, market (economic) barriers, utility and developer business model barriers, cross-cutting barriers and technology barriers.

  13. Evidence on the cost-effectiveness of lifelong antiretroviral therapy for prevention of mother-to-child transmission of HIV: implications for resource-limited countries in sub-Saharan Africa.

    Science.gov (United States)

    Ngambi, Peslie G; Kalungia, Aubrey C; Law, Michael R; Kalemeera, Francis; Truter, IIse; Godman, Brian; Munkombwe, Derick

    2017-10-01

    The 2016 World Health Organization (WHO) consolidated guideline recommends lifelong antiretroviral therapy (ART) for all HIV-infected pregnant and breastfeeding women for preventing mother-to-child HIV transmission (PMTCT). Ambiguity remains about the cost-effectiveness of this strategy in resource-limited developing countries. Areas covered: We reviewed model-based studies on the cost-effectiveness of lifelong ART (formerly Option B+) relative to previous WHO guidelines for PMTCT. Our search using PubMed, Medline and Google Scholar for articles on Option B+ resulted in the final inclusion of seven studies published between 2012 and 2016. The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) checklist was used to assess the quality of reporting. Outcomes of interest, which included infant infections averted, maternal quality and length of life, and the Incremental Cost Effectiveness Ratio (ICER), were used in comparing cost-effectiveness. Expert commentary: Despite most model-based studies favouring lifelong ART (Option B+) in terms of its cost-effectiveness in comparison to Options A and B, inclusiveness of the evidence remains weak for generalization. This is largely because setting specificity for providing lifelong ART to all pregnant and breastfeeding women may differ significantly in each setting. Consequently, future cost-effectiveness studies should be robust, setting-specific, and endeavor to assess the willingness and ability to pay of each setting.

  14. Hendra virus ecology and transmission.

    Science.gov (United States)

    Field, Hume E

    2016-02-01

    Hendra virus causes acute and highly fatal infection in horses and humans. Pteropid bats (flying-foxes) are the natural host of the virus, with age and species being risk factors for infection. Urine is the primary route of excretion in flying-foxes, with viral RNA more frequently detected in Pteropus alecto and P. conspicillatus than other species. Infection prevalence in flying-foxes can vary between and within years, with a winter peak of excretion occurring in some regions. Vertical transmission and recrudescing infection has been reported in flying-foxes, but horizontal transmission is evidently the primary mode of transmission. The most parsimonious mode of flying-fox to horse transmission is equine contact (oro-nasal, conjunctival) with infected flying-fox urine, either directly, or via urine-contaminated pasture or surfaces. Horse to horse transmission is inefficient, requiring direct contact with infected body fluids. Flying-fox to human transmission has not been recorded; all human cases have been associated with close and direct contact with infected horses. Canine cases (subclinical) have also been limited to equine case properties. Notwithstanding the recent availability of an effective vaccine for horses, a comprehensive understanding of Hendra virus ecology and transmission is essential to limit inter-species transmission. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Effect on transmission of HIV-1 resistance of timing of implementation of viral load monitoring to determine switches from first to second-line antiretroviral regimens in resource-limited settings

    DEFF Research Database (Denmark)

    Phillips, Andrew N; Pillay, Deenan; Garnett, Geoff

    2011-01-01

    There is concern that antiretroviral therapy (ART) use with only clinical monitoring for failure will result in high rates of transmission of virus with resistance to drugs currently in use.......There is concern that antiretroviral therapy (ART) use with only clinical monitoring for failure will result in high rates of transmission of virus with resistance to drugs currently in use....

  16. Reaction rate calculations via transmission coefficients

    International Nuclear Information System (INIS)

    Feit, M.D.; Alder, B.J.

    1985-01-01

    The transmission coefficient of a wavepacket traversing a potential barrier can be determined by steady state calculations carried out in imaginary time instead of by real time dynamical calculations. The general argument is verified for the Eckart barrier potential by a comparison of transmission coefficients calculated from real and imaginary time solutions of the Schroedinger equation. The correspondence demonstrated here allows a formulation for the reaction rate that avoids difficulties due to both rare events and explicitly time dependent calculations. 5 refs., 2 figs

  17. Linguistic Barriers and Bridges

    DEFF Research Database (Denmark)

    Thuesen, Frederik

    2016-01-01

    The influence of language on social capital in low-skill and ethnically diverse workplaces has thus far received very limited attention within the sociology of work. As the ethnically diverse workplace is an important social space for the construction of social relations bridging different social...... and intercultural communication, this article analyses interviews with 31 employees from two highly ethnically diverse Danish workplaces. The article shows how linguistic barriers such as different levels of majority language competence and their consequent misunderstandings breed mistrust and hostility, whilst...... communication related to collaboration and ‘small talk’ may provide linguistic bridges to social capital formation....

  18. Pathogen population bottlenecks and adaptive landscapes: overcoming the barriers to disease emergence.

    Science.gov (United States)

    Geoghegan, Jemma L; Senior, Alistair M; Holmes, Edward C

    2016-08-31

    Emerging diseases are a major challenge to public health. Revealing the evolutionary processes that allow novel pathogens to adapt to new hosts, also the potential barriers to host adaptation, is central to understanding the drivers of disease emergence. In particular, it is unclear how the genetics and ecology of pathogens interact to shape the likelihood of successful cross-species transmission. To better understand the determinants of host adaptation and emergence, we modelled key aspects of pathogen evolutionary dynamics at both intra- and inter-host scales, using parameter values similar to those observed in influenza virus. We considered the possibility of acquiring the necessary host adaptive mutations both before ('off-the-shelf' emergence) and after ('tailor-made' emergence) a virus is transmitted from a donor to a new recipient species. Under both scenarios, population bottlenecks at inter-host transmission act as a major barrier to host adaptation, greatly limiting the number of adaptive mutations that are able to cross the species barrier. In addition, virus emergence is hindered if the fitness valley between the donor and recipient hosts is either too steep or too shallow. Overall, our results reveal where in evolutionary parameter space a virus could adapt to and become transmissible in a new species. © 2016 The Author(s).

  19. Open access to transmission

    International Nuclear Information System (INIS)

    Keith, D.M.

    1996-01-01

    For the past 12 to 15 years, the US electric power and energy industry and its federal regulators have been going through a prolonged exercise leading to opening up the national interconnected transmission grid for all qualified wholesale users to have open and equal access. The debates have been painful in a sense that not all parties - especially some of the transmission system owning utilities - believe that the concept of Open Access is achievable, due to technical constraints on the systems. The present Open Access activity is limited to wholesales transaction under the federal jurisdiction, but several states are either experimenting with or considering retail wheeling. In fact, the FERC - Federal Energy Regulatory Commission - has already expanded its view to embrace retail transmission, if the retail transaction involves the use of the interstate transmission systems which are under FERC's jurisdiction. This paper delves into some of the results of the technical cost and pricing analysis for open access. The statutes and resulting regulations are not addressed herein. (author). 1 fig

  20. Transcending Transmission

    DEFF Research Database (Denmark)

    Schoeneborn, Dennis; Trittin, Hannah

    2013-01-01

    Purpose – Extant research on corporate social responsibility (CSR) communication primarily relies on a transmission model of communication that treats organizations and communication as distinct phenomena. This approach has been criticized for neglecting the formative role of communication...... in the emergence of organizations. This paper seeks to propose to reconceptualize CSR communication by drawing on the “communication constitutes organizations” (CCO) perspective. Design/methodology/approach – This is a conceptual paper that explores the implications of switching from an instrumental...... are stabilized by various non-human entities that “act” on their behalf. Accordingly, CSR communication should also take into account non-human agency and responsibility. Originality/value – This paper links the literature on CSR communication to broader debates in organizational communication studies and...

  1. Multilayer barrier films comprising nitrogen spacers between free-standing barrier layers

    Science.gov (United States)

    Granstrom, Jimmy; Villet, Michael; Chatterjee, Tirtha; Gerbec, Jeffrey A.; Jerkunica, Evan; Roy, Anshuman

    2009-08-01

    An encapsulation architecture for organic electronic devices utilizing nitrogen gas-phase spacers between free-standing barrier films is demonstrated. The nitrogen spacers act as sinks for permeating H2O and O2, delaying establishment of steady-state chemical potential gradients across the barriers and thereby reducing permeation rates. Water vapor transmission through nitrogen-spaced barriers was measured via the calcium optical transmission test. Substantial reductions in permeation rate were observed for a variety of barrier materials and configurations, suggesting a general and cost-effective approach for improving encapsulation performance. A low-cost polyethylene terephthalate film increases the calcium lifetime of a Cytop™-Kureha structure from 7000 to 12000 min.

  2. Transmission reliability faces future challenges

    International Nuclear Information System (INIS)

    Beaty, W.

    1993-01-01

    The recently published Washington International Energy Group's 1993 Electric Utility Outlook states that nearly one-third (31 percent) of U.S. utility executives expect reliability to decrease in the near future. Electric power system stability is crucial to reliability. Stability analysis determines whether a system will stay intact under normal operating conditions, during minor disturbances such as load fluctuations, and during major disturbances when one or more parts of the system fails. All system elements contribute to reliability or the lack of it. However, this report centers on the transmission segment of the electric system. The North American Electric Reliability Council (NERC) says the transmission systems as planned will be adequate over the next 10 years. However, delays in building new lines and increasing demands for transmission services are serious concerns. Reliability concerns exist in the Mid-Continent Area Power Pool and the Mid-America Interconnected Network regions where transmission facilities have not been allowed to be constructed as planned. Portions of the transmission systems in other regions are loaded at or near their limits. NERC further states that utilities must be allowed to complete planned generation and transmission as scheduled. A reliable supply of electricity also depends on adhering to established operating criteria. Factors that could complicate operations include: More interchange schedules resulting from increased transmission services. Increased line loadings in portions of the transmission systems. Proliferation of non-utility generators

  3. Gas transmission through microporous membranes

    Science.gov (United States)

    Turel, Tacibaht

    2008-10-01

    An ideal protective clothing material should be a good barrier against harmful gases or vapor while allowing moisture vapor and air passage through the material. In the study and design of barrier materials, one of the critical issues is to balance these requirements, which may sometimes be mutually exclusive. Therefore it is critical to understand the macroscopic and microscopic structure of the attack mechanisms as well as the barrier materials and the transport phenomena in such systems. In this study, air and gas transmission through barrier systems consisting of porous membranes was investigated experimentally and a molecular-level probabilistic model was constructed to evaluate the effect of various parameters on the gas flow. The effect of membrane parameters such as porosity, pore size distribution, thickness as well as gas parameters such as molecule diameters were examined at single layer as well as multiple layers. To understand the gas behavior for harmful chemicals and to ensure safety during experimental studies, mimics of such gases were obtained which were comparable to the actual gases in shape, molecular weight and other chemical properties. Air, ammonia and several mimic gases of harmful chemical agents were studied. Beta-pinene was used as a mimic of sarin and prenol was used as a mimic of nitrogen mustard. Gas transmission experiments were conducted on polyester, nylon and polypropylene membranes each of which had different porosity and pore size distributions. Experiments were done at different pressure values and a comparison was made between permeability testing machines based on volumetric and manometric principles as to their ability to accommodate high permeability membranes. Physical and chemical adsorption of such gases on porous membranes was also investigated after the addition of active elements on the membrane surfaces which can interact with the gas molecules. An experimental setup was developed to measure concentration changes

  4. Quantum dynamics of a particle interacting with a double barrier

    International Nuclear Information System (INIS)

    Cacciari, Ilaria; Lantieri, Marco; Moretti, Paolo

    2007-01-01

    Following a previously developed method, the problem of a particle scattered by a double barrier is studied. Instead of the simple transmission or reflection, the more difficult case of the arrival in the region between the barriers is considered and solved explicitly by using matrix methods

  5. Graphene Oxide Bionanocomposite Coatings with High Oxygen Barrier Properties

    Directory of Open Access Journals (Sweden)

    Ilke Uysal Unalan

    2016-12-01

    Full Text Available In this work, we present the development of bionanocomposite coatings on poly(ethylene terephthalate (PET with outstanding oxygen barrier properties. Pullulan and graphene oxide (GO were used as main polymer phase and nanobuilding block (NBB, respectively. The oxygen barrier performance was investigated at different filler volume fractions (ϕ and as a function of different relative humidity (RH values. Noticeably, the impermeable nature of GO was reflected under dry conditions, in which an oxygen transmission rate (OTR, mL·m−2·24 h−1 value below the detection limit of the instrument (0.01 mL·m−2·24 h−1 was recorded, even for ϕ as low as 0.0004. A dramatic increase of the OTR values occurred in humid conditions, such that the barrier performance was totally lost at 90% RH (the OTR of coated PET films was equal to the OTR of bare PET films. Modelling of the experimental OTR data by Cussler’s model suggested that the spatial ordering of GO sheets within the main pullulan phase was perturbed because of RH fluctuations. In spite of the presence of the filler, all the formulations allowed the obtainment of final materials with haze values below 3%, the only exception being the formulation with the highest loading of GO (ϕ ≈ 0.03. The mechanisms underlying the experimental observations are discussed.

  6. Barriers for realisation of energy savings in buildings; Barrierer for realisering af energibesparelser i bygninger

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, O.M.

    2004-07-01

    Many years' efforts within the energy labelling area have shown large saving potentials in heating and use of electricity in buildings. At the same time it has been proved that these saving potentials, even when economically advantageous, only are cashed to a limited extent. The reason to this is ascribed to barriers that meet the individual building owner who wants to start saving energy. Most barriers are known and a lot of these have been sought overcome for some time. The questions are how many barriers still exist, have new barriers arisen and the character of these barriers. On this background the objective of this survey has been to concretize and study the barriers, which are blocking reasonable energy savings. Focus has especially been on barriers for realisation of heating savings, but through a general evaluation of energy savings of barriers other forms of energy saving methods have been taken into consideration. Special interest has been directed towards houses, typically one family houses, which are affected by the Energy Labelling Scheme. The concept barriers include all kinds of barriers, also barriers that not are acknowledged as barriers by the individual house owner, or that on closer inspection turn out to be something else than actual barriers. This note suggests an alternative inertia model, in order to create an idea of the inertness characteristic of the many house owners who understand the message but fail to act on it. (BA)

  7. Self-regulation of turbulence bursts and transport barriers

    International Nuclear Information System (INIS)

    Floriani, E; Ciraolo, G; Ghendrih, Ph; Sarazin, Y; Lima, R

    2013-01-01

    The interplay between turbulent bursts and transport barriers is analyzed with a simplified model of interchange turbulence in magnetically confined plasmas. The turbulent bursts spread into the transport barriers and, depending on the competing magnitude of the burst and stopping capability of the barrier, can burn through. Simulations of two models of transport barriers are presented: a hard barrier where interchange turbulence modes are stable in a prescribed region and a soft barrier with external plasma biasing. The response of the transport barriers to the non-linear perturbations of the turbulent bursts, addressed in a predator–prey approach, indicates that the barriers monitor an amplification factor of the turbulent bursts, with amplification smaller than one for most bursts and, in some cases, amplification factors that can significantly exceed unity. The weak barriers in corrugated profiles and magnetic structures, as well as the standard barriers, are characterized by these transmission properties, which then regulate the turbulent burst transport properties. The interplays of barriers and turbulent bursts are modeled as competing stochastic processes. For different classes of the probability density function (PDF) of these processes, one can predict the heavy tail properties of the bursts downstream from the barrier, either exponential for a leaky barrier, or with power laws for a tight barrier. The intrinsic probing of the transport barriers by the turbulent bursts thus gives access to the properties of the barriers. The main stochastic variables are the barrier width and the spreading distance of the turbulent bursts within the barrier, together with their level of correlation. One finds that in the case of a barrier with volumetric losses, such as radiation or particle losses as addressed in our present simulations, the stochastic model predicts a leaky behavior with an exponential PDF of escaping turbulent bursts in agreement with the simulation

  8. Planning Electric Transmission Lines: A Review of Recent Regional Transmission Plans

    Energy Technology Data Exchange (ETDEWEB)

    Eto, Joseph H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-04-13

    The first Quadrennial Energy Review (QER) recommends that the U.S. Department of Energy (DOE) conduct a national review of transmission plans and assess the barriers and incentives to their implementation. DOE tasked Lawrence Berkeley National Laboratory (LBNL) to prepare two reports to support the agency’s response to this recommendation. This report reviews regional transmission plans and regional transmission planning processes that have been directed by Federal Energy Regulatory Commission (FERC) Order Nos. 890 and 1000. We focus on the most recent regional transmission plans (those issued in 2015 and through approximately mid-year 2016) and current regional transmission planning processes. A companion report focuses on non-plan-related factors that affect transmission projects.

  9. Adiabatic heavy-ion fusion potentials for fusion at deep sub-barrier ...

    Indian Academy of Sciences (India)

    Abstract. The recently reported unusual behaviour of fusion cross-sections at extreme sub-barrier energies has been examined. The adiabatic limit of fusion barriers has been determined from experimental data using the barrier penetration model. These adia- batic barriers are consistent with the adiabatic fusion barriers ...

  10. Molecular Modeling of Prion Transmission to Humans

    Directory of Open Access Journals (Sweden)

    Etienne Levavasseur

    2014-10-01

    Full Text Available Using different prion strains, such as the variant Creutzfeldt-Jakob disease agent and the atypical bovine spongiform encephalopathy agents, and using transgenic mice expressing human or bovine prion protein, we assessed the reliability of protein misfolding cyclic amplification (PMCA to model interspecies and genetic barriers to prion transmission. We compared our PMCA results with in vivo transmission data characterized by attack rates, i.e., the percentage of inoculated mice that developed the disease. Using 19 seed/substrate combinations, we observed that a significant PMCA amplification was only obtained when the mouse line used as substrate is susceptible to the corresponding strain. Our results suggest that PMCA provides a useful tool to study genetic barriers to transmission and to study the zoonotic potential of emerging prion strains.

  11. Subsurface barrier verification technologies, informal report

    International Nuclear Information System (INIS)

    Heiser, J.H.

    1994-06-01

    One of the more promising remediation options available to the DOE waste management community is subsurface barriers. Some of the uses of subsurface barriers include surrounding and/or containing buried waste, as secondary confinement of underground storage tanks, to direct or contain subsurface contaminant plumes and to restrict remediation methods, such as vacuum extraction, to a limited area. To be most effective the barriers should be continuous and depending on use, have few or no breaches. A breach may be formed through numerous pathways including: discontinuous grout application, from joints between panels and from cracking due to grout curing or wet-dry cycling. The ability to verify barrier integrity is valuable to the DOE, EPA, and commercial sector and will be required to gain full public acceptance of subsurface barriers as either primary or secondary confinement at waste sites. It is recognized that no suitable method exists for the verification of an emplaced barrier's integrity. The large size and deep placement of subsurface barriers makes detection of leaks challenging. This becomes magnified if the permissible leakage from the site is low. Detection of small cracks (fractions of an inch) at depths of 100 feet or more has not been possible using existing surface geophysical techniques. Compounding the problem of locating flaws in a barrier is the fact that no placement technology can guarantee the completeness or integrity of the emplaced barrier. This report summarizes several commonly used or promising technologies that have been or may be applied to in-situ barrier continuity verification

  12. Smart parking barrier

    KAUST Repository

    Alharbi, Abdulrazaq M.

    2016-05-06

    Various methods and systems are provided for smart parking barriers. In one example, among others, a smart parking barrier system includes a movable parking barrier located at one end of a parking space, a barrier drive configured to control positioning of the movable parking barrier, and a parking controller configured to initiate movement of the parking barrier, via the barrier drive. The movable parking barrier can be positioned between a first position that restricts access to the parking space and a second position that allows access to the parking space. The parking controller can initiate movement of the movable parking barrier in response to a positive identification of an individual allowed to use the parking space. The parking controller can identify the individual through, e.g., a RFID tag, a mobile device (e.g., a remote control, smartphone, tablet, etc.), an access card, biometric information, or other appropriate identifier.

  13. Survey of Transmission Cost Allocation Methodologies for Regional Transmission Organizations

    Energy Technology Data Exchange (ETDEWEB)

    Fink, S.; Porter, K.; Mudd, C.; Rogers, J.

    2011-02-01

    The report presents transmission cost allocation methodologies for reliability transmission projects, generation interconnection, and economic transmission projects for all Regional Transmission Organizations.

  14. Patterns of measles transmission among airplane travelers.

    Science.gov (United States)

    Edelson, Paul J

    2012-09-01

    With advanced air handling systems on modern aircraft and the high level of measles immunity in many countries, measles infection in air travelers may be considered a low-risk event. However, introduction of measles into countries where transmission has been controlled or eliminated can have substantial consequences both for the use of public health resources and for those still susceptible. In an effort to balance the relatively low likelihood of disease transmission among largely immune travelers and the risk to the public health of the occurrence of secondary cases resulting from importations, criteria in the United States for contact investigations for measles exposures consider contacts to be those passengers who are seated within 2 rows of the index case. However, recent work has shown that cabin air flow may not be as reliable a barrier to the spread of measles virus as previously believed. Along with these new studies, several reports have described measles developing after travel in passengers seated some distance from the index case. To understand better the potential for measles virus to spread on an airplane, reports of apparent secondary cases occurring in co-travelers of passengers with infectious cases of measles were reviewed. Medline™ was searched for articles in all languages from 1946 to week 1 of March 2012, using the search terms "measles [human] or rubeola" and ("aircraft" or "airplane" or "aeroplane" or "aviation" or "travel" or "traveler" or "traveller"); 45 citations were returned. Embase™ was searched from 1988 to week 11 2012, using the same search strategy; 95 citations were returned. Papers were included in this review if they reported secondary cases of measles occurring in persons traveling on an airplane on which a person or persons with measles also flew, and which included the seating location of both the index case(s) and the secondary case(s) on the plane. Nine reports, including 13 index cases and 23 apparent secondary cases

  15. Transmissible spongiform encephalopathies.

    Science.gov (United States)

    Liemann, S; Glockshuber, R

    1998-09-18

    Scrapie, bovine spongiform encephalopathy (BSE), and the Creutzfeldt-Jakob disease (CJD) belong to a group of lethal neurodegenerative disorders in mammals. Prion diseases or transmissible spongiform encephalopathies (TSEs) are characterized by the accumulation of an abnormal isoform (PrPSc) of the host-encoded cellular prion protein (PrPC) in the brain. The infectious agent, the 'prion,' is believed to be devoid of informational nucleic acid and to consist largely, if not entirely, of PrPSc. The PrP isoforms contain identical amino acid sequences yet differ in their overall secondary structure with the PrPSc isoform possessing a higher beta-sheet and lower alpha-helix content than PrPC. Elucidation of the three-dimensional structure of PrPC has provided important clues on the molecular basis of inherited human TSEs and on the species barrier phenomenon of TSEs. Nevertheless, the molecular mechanism of the conformational rearrangement of PrPC into PrPSc is still unknown, mainly due to the lack of detailed structural information on PrPSc. Within the framework of the 'protein only' hypothesis, two plausible models for the self-replication of prions have been suggested, the conformational model and the nucleation-dependent polymerization model.

  16. Anisotropic tunneling resistance in a phosphorene-based magnetic barrier

    Science.gov (United States)

    Zhai, Feng; Hu, Wei; Lu, Junqiang

    2017-10-01

    We investigate the ballistic tunneling transport properties of a monolayer of black phosphorus under a magnetic barrier. The conductance of the system depends strongly on the orientation of the magnetic barrier, which is suppressed maximally when the magnetic barrier is oriented along the armchair direction. The mechanism relies on the highly anisotropic energy dispersion of phosphorene and the magnetic-barrier-induced suppression of available phase space for transmission. The magnetoresistance is enhanced by the reduction of the band gap under the same effective mass components.

  17. Energy Transmission and Infrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Mathison, Jane

    2012-12-31

    The objective of Energy Transmission and Infrastructure Northern Ohio (OH) was to lay the conceptual and analytical foundation for an energy economy in northern Ohio that will: • improve the efficiency with which energy is used in the residential, commercial, industrial, agricultural, and transportation sectors for Oberlin, Ohio as a district-wide model for Congressional District OH-09; • identify the potential to deploy wind and solar technologies and the most effective configuration for the regional energy system (i.e., the ratio of distributed or centralized power generation); • analyze the potential within the district to utilize farm wastes to produce biofuels; • enhance long-term energy security by identifying ways to deploy local resources and building Ohio-based enterprises; • identify the policy, regulatory, and financial barriers impeding development of a new energy system; and • improve energy infrastructure within Congressional District OH-09. This objective of laying the foundation for a renewable energy system in Ohio was achieved through four primary areas of activity: 1. district-wide energy infrastructure assessments and alternative-energy transmission studies; 2. energy infrastructure improvement projects undertaken by American Municipal Power (AMP) affiliates in the northern Ohio communities of Elmore, Oak Harbor, and Wellington; 3. Oberlin, OH-area energy assessment initiatives; and 4. a district-wide conference held in September 2011 to disseminate year-one findings. The grant supported 17 research studies by leading energy, policy, and financial specialists, including studies on: current energy use in the district and the Oberlin area; regional potential for energy generation from renewable sources such as solar power, wind, and farm-waste; energy and transportation strategies for transitioning the City of Oberlin entirely to renewable resources and considering pedestrians, bicyclists, and public transportation as well as drivers

  18. Vibration measurements on a car transmission housing

    Science.gov (United States)

    Weber, Wolfram; Plieske, Marco; Brauchle, Gerhard

    1994-09-01

    In view of stricter future statutory requirements concerning noise emissions by motor vehicles, the acoustic optimization of noise emitting components will become increasingly important. Customers complain about transmission noise when for example gears excite individual resonances (eigenfrequencies) of the transmission housing. Normally the eigenfrequencies and also the excitation frequencies are not moveable out of narrow limits. Therefore, in addition to optimizing gear geometry, the transmission housing must be designed so that dynamic forces acting through the gears onto the shaft bearing points lead to minimum level of radiated sound power from the transmission housing. For this reason, the resonance vibration shapes induced on a car transmission under operating conditions were measured using the laser-transmission test rig. Additionally, a comparison was made between the inspection of an empty transmission housing (using finite element calculation and experimental modal analysis).

  19. Super Gas Barrier Thin Films via Layer-by-Layer Assembly of Polyelectrolytes and Clay

    Science.gov (United States)

    Priolo, Morgan; Gamboa, Daniel; Grunlan, Jaime

    2010-03-01

    Thin composite films of branched polyethylenimine (PEI), polyacrylic acid (PAA) and sodium montmorillonite clay (MMT) platelets were prepared using layer-by-layer assembly. Film thickness, mass deposited per layer, and barrier were shown to increase exponentially with the number of deposition cycles. After 32 layers (i.e., eight PEI/PAA/PEI/MMT quadlayers) are deposited, the resulting transparent film exhibits an oxygen transmission rate below the detection limit of commercial instrumentation (clay bricks in polymeric mortar, where the enhanced spacing between MMT layers, provided by PEI and PAA, creates channels perpendicular concentration gradient that delay the permeating molecule. These films are good candidates for flexible electronics, food, and pharmaceutical packaging due to their transparency, super gas barrier (that rivals SiOx) and lack of metal.

  20. Safety-barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2007-01-01

    are discussed. A simple method for quantification of safety-barrier diagrams is proposed, including situations where safety barriers depend on shared common elements. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk...

  1. Social Barriers to Effective Communication in Old Age

    OpenAIRE

    Anna Sanecka

    2014-01-01

    Some communication barriers apply particularly to elderly people. The social barriers to effective communication in old age are the barriers caused by stereotypes of old age/elderly people and the barriers arising from limitations in using mass communication by seniors. Stereotypes of old age/elderly people embrace views regarding old people’s communication skills and the ideas about the correct way of communication with them. Therefore the communication problems of old people are correlated ...

  2. Skin barrier function

    DEFF Research Database (Denmark)

    2016-01-01

    barrier integrity, factors influencing the penetration of the skin, influence of wet work, and guidance for prevention and saving the barrier. Distinguished researchers have contributed to this book, providing a comprehensive and thorough overview of the skin barrier function. Researchers in the field...... on the subject. It covers new basic research on skin markers, including results on filaggrin and on methods for the assessment of the barrier function. Biological variation and aspects of skin barrier function restoration are discussed as well. Further sections are dedicated to clinical implications of skin...

  3. Safety- barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2008-01-01

    trees and Bayesian networks is discussed. A simple method for quantification of safety-barrier diagrams is proposed. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk analysis with operational safety management.......Safety-barrier diagrams and the related so-called 'bow-tie' diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation of safety-barrier diagrams to other methods such as fault...

  4. Safety-barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2007-01-01

    Safety-barrier diagrams and the related so-called "bow-tie" diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation with other methods such as fault trees and Bayesian network...... analysis with operational safety management.......Safety-barrier diagrams and the related so-called "bow-tie" diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation with other methods such as fault trees and Bayesian networks...... are discussed. A simple method for quantification of safety-barrier diagrams is proposed, including situations where safety barriers depend on shared common elements. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk...

  5. Broadband transmission EPR spectroscopy.

    Directory of Open Access Journals (Sweden)

    Wilfred R Hagen

    Full Text Available EPR spectroscopy employs a resonator operating at a single microwave frequency and phase-sensitive detection using modulation of the magnetic field. The X-band spectrometer is the general standard with a frequency in the 9-10 GHz range. Most (biomolecular EPR spectra are determined by a combination of the frequency-dependent electronic Zeeman interaction and a number of frequency-independent interactions, notably, electron spin - nuclear spin interactions and electron spin - electron spin interactions, and unambiguous analysis requires data collection at different frequencies. Extant and long-standing practice is to use a different spectrometer for each frequency. We explore the alternative of replacing the narrow-band source plus single-mode resonator with a continuously tunable microwave source plus a non-resonant coaxial transmission cell in an unmodulated external field. Our source is an arbitrary wave digital signal generator producing an amplitude-modulated sinusoidal microwave in combination with a broadband amplifier for 0.8-2.7 GHz. Theory is developed for coaxial transmission with EPR detection as a function of cell dimensions and materials. We explore examples of a doublet system, a high-spin system, and an integer-spin system. Long, straigth, helical, and helico-toroidal cells are developed and tested with dilute aqueous solutions of spin label hydroxy-tempo. A detection limit of circa 5 µM HO-tempo in water at 800 MHz is obtained for the present setup, and possibilities for future improvement are discussed.

  6. Barriers to initiating tuberculosis treatment in sub-Saharan Africa: a systematic review focused on children and youth.

    Science.gov (United States)

    Sullivan, Brittney J; Esmaili, B Emily; Cunningham, Coleen K

    2017-01-01

    Tuberculosis (TB) is the deadliest infectious disease globally, with 10.4 million people infected and more than 1.8 million deaths in 2015. TB is a preventable, treatable, and curable disease, yet there are numerous barriers to initiating treatment. These barriers to treatment are exacerbated in low-resource settings and may be compounded by factors related to childhood. Timely initiation of tuberculosis (TB) treatment is critical to reducing disease transmission and improving patient outcomes. The aim of this paper is to describe patient- and system-level barriers to TB treatment initiation specifically for children and youth in sub-Saharan Africa through systematic review of the literature. This review was conducted in October 2015 in accordance with preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Six databases were searched to identify studies where primary or secondary objectives were related to barriers to TB treatment initiation and which included children or youth 0-24 years of age. A total of 1490 manuscripts met screening criteria; 152 met criteria for full-text review and 47 for analysis. Patient-level barriers included limited knowledge, attitudes and beliefs regarding TB, and economic burdens. System-level barriers included centralization of services, health system delays, and geographical access to healthcare. Of the 47 studies included, 7 evaluated cost, 19 health-seeking behaviors, and 29 health system infrastructure. Only 4 studies primarily assessed pediatric cohorts yet all 47 studies were inclusive of children. Recognizing and removing barriers to treatment initiation for pediatric TB in sub-Saharan Africa are critical. Both patient- and system-level barriers must be better researched in order to improve patient outcomes.

  7. Transfusion transmissible viral infections among potential blood ...

    African Journals Online (AJOL)

    effective approach for prevention and control of transfusion-transmissible infections (TTIs). Also, it has been documented that sub-standard test kits are mostly used in resource limited settings for transfusion related diagnosis. However, the role of ...

  8. Unified Model of Dynamic Forced Barrier Crossing in Single Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Friddle, R W

    2007-06-21

    Thermally activated barrier crossing in the presence of an increasing load can reveal kinetic rate constants and energy barrier parameters when repeated over a range of loading rates. Here we derive a model of the mean escape force for all relevant loading rates--the complete force spectrum. Two well-known approximations emerge as limiting cases; one of which confirms predictions that single-barrier spectra should converge to a phenomenological description in the slow loading limit.

  9. Transmission Planning Process and Opportunities for Utility-Scale Solar Engagement within the Western Electricity Coordinating Council (WECC)

    Energy Technology Data Exchange (ETDEWEB)

    Hein, J.; Hurlbut, D.; Milligan, M.; Coles, L.; Green, B.

    2011-11-01

    This report is a primer for solar developers who wish to engage directly in expediting the regulatory process and removing market barriers related to policy and planning. Market barriers unrelated to technology often limit the expansion of utility-scale solar power, even in areas with exceptional resource potential. Many of these non-technical barriers have to do with policy, regulation, and planning, and hardly ever do they resolve themselves in a timely fashion. In most cases, pre-emptive intervention by interested stakeholders is the easiest way to remove/address such barriers, but it requires knowing how to navigate the institutional waters of the relevant agencies and boards. This report is a primer for solar developers who wish to engage directly in expediting the regulatory process and removing market barriers related to policy and planning. It focuses on the Western Interconnection (WI), primarily because the quality of solar resources in the Southwest makes utility-scale concentrating solar power (CSP) and photovoltaics (PV) economically feasible, and because the relevant institutions have evolved in a way that has opened up opportunities for removing non-technical market barriers. Developers will find in this report a high-level field manual to identify the venues for mitigating and possibly eliminating systemic market obstacles and ensuring that the economic playing field is reasonably level. Project-specific issues such as siting for transmission and generation resources are beyond the scope of this report. Instead, the aim is to examine issues that pervasively affect all utility-scale PV and CSP in the region regardless of where the project may be. While the focus is on the WI, many of the institutions described here also have their counterparts in the Eastern and the Texas interconnections. Specifically, this report suggests a number of critical engagement points relating to generation and transmission planning.

  10. Current transmission and nonlinear effects in un-gated thermionic cathode RF guns

    Energy Technology Data Exchange (ETDEWEB)

    Edelen, J. P. [Fermilab; Harris, J. R. [Air Force Weapons Lab

    2017-05-03

    Un-gated thermionic cathode RF guns are well known as a robust source of electrons for many accelerator applications. These sources are in principle scalable to high currents without degradation of the transverse emittance due to control grids but they are also known for being limited by back-bombardment. While back-bombardment presents a significant limitation, there is still a lack of general understanding on how emission over the whole RF period will affect the nature of the beams produced from these guns. In order to improve our understanding of how these guns can be used in general we develop analytical models that predict the transmission efficiency as a function of the design parameters, study how bunch compression and emission enhancement caused by Schottky barrier lowering affect the output current profile in the gun, and study the onset of space-charge limited effects and the resultant virtual cathode formation leading to a modulation in the output current distribution.

  11. Quantum coherence in the reflection of above barrier wavepackets.

    Science.gov (United States)

    Petersen, Jakob; Pollak, Eli

    2018-02-21

    The quantum phenomenon of above barrier reflection is investigated from a time-dependent perspective using Gaussian wavepackets. The transition path time distribution, which in principle is experimentally measurable, is used to study the mean flight times ⟨t⟩ R and ⟨t⟩ T associated with the reflection and the transmission over the barrier paying special attention to their dependence on the width of the barrier. Both flight times, and their difference Δt, exhibit two distinct regimes depending on the ratio of the spatial width of the incident wavepacket and the length of the barrier. When the ratio is larger than unity, the reflection and transmission dynamics are coherent and dominated by the resonances above the barrier. The flight times ⟨t⟩ R/T and the flight time difference Δt oscillate as a function of the barrier width (almost in phase with the transmission probability). These oscillations reflect a momentum filtering effect related to the coherent superposition of the reflected and transmitted waves. For a ratio less than unity, the barrier reflection and transmission dynamics are incoherent and the oscillations are absent. The barrier width which separates the coherent and incoherent regimes is identified analytically. The oscillatory structure of the time difference Δt as a function of the barrier width in the coherent regime is absent when considered in terms of the Wigner phase time delays for reflection and transmission. We conclude that the Wigner phase time does not correctly describe the temporal properties of above barrier reflection. We also find that the structure of the reflected and transmitted wavepackets depends on the coherence of the process. In the coherent regime, the wavepackets can have an overlapping peak structure, but the peaks are not fully resolved. In the incoherent regime, the wavepackets split in time into distinct separated Gaussian like waves, each one reflecting the number of times the wavepacket crosses the

  12. Quantum coherence in the reflection of above barrier wavepackets

    Science.gov (United States)

    Petersen, Jakob; Pollak, Eli

    2018-02-01

    The quantum phenomenon of above barrier reflection is investigated from a time-dependent perspective using Gaussian wavepackets. The transition path time distribution, which in principle is experimentally measurable, is used to study the mean flight times ⟨t⟩R and ⟨t⟩T associated with the reflection and the transmission over the barrier paying special attention to their dependence on the width of the barrier. Both flight times, and their difference Δt, exhibit two distinct regimes depending on the ratio of the spatial width of the incident wavepacket and the length of the barrier. When the ratio is larger than unity, the reflection and transmission dynamics are coherent and dominated by the resonances above the barrier. The flight times ⟨t⟩R/T and the flight time difference Δt oscillate as a function of the barrier width (almost in phase with the transmission probability). These oscillations reflect a momentum filtering effect related to the coherent superposition of the reflected and transmitted waves. For a ratio less than unity, the barrier reflection and transmission dynamics are incoherent and the oscillations are absent. The barrier width which separates the coherent and incoherent regimes is identified analytically. The oscillatory structure of the time difference Δt as a function of the barrier width in the coherent regime is absent when considered in terms of the Wigner phase time delays for reflection and transmission. We conclude that the Wigner phase time does not correctly describe the temporal properties of above barrier reflection. We also find that the structure of the reflected and transmitted wavepackets depends on the coherence of the process. In the coherent regime, the wavepackets can have an overlapping peak structure, but the peaks are not fully resolved. In the incoherent regime, the wavepackets split in time into distinct separated Gaussian like waves, each one reflecting the number of times the wavepacket crosses the barrier

  13. Thermal barriers for compartments

    Science.gov (United States)

    Kreutzer, Cory J.; Lustbader, Jason A.

    2017-10-17

    An aspect of the present disclosure is a thermal barrier that includes a core layer having a first surface, a second surface, and a first edge, and a first outer layer that includes a third surface and a second edge, where the third surface substantially contacts the first surface, the core layer is configured to minimize conductive heat transfer through the barrier, and the first outer layer is configured to maximize reflection of light away from the barrier.

  14. A review of the risk of contamination of semen and embryos during cryopreservation and measures to limit cross-contamination during banking to prevent disease transmission in ET practices.

    Science.gov (United States)

    Bielanski, A

    2012-02-01

    This review summarizes pertinent data and opinions regarding the potential hazard of disease transmission through cryopreserved and banked embryos in liquid nitrogen (LN). Special attention is given to the survival of pathogens in LN, new vitrification methods, sterility of LN, risks associated with the use of straws and cryovials, and LN dewars including dry shippers. It was experimentally demonstrated that cross-contamination between LN and embryos may occur, when infectious agents are present in LN and embryos are not protected by a sealed container. It is important, therefore, to prevent direct contact of embryos with LN during cryopreservation and their banking. This includes the usage of hermetically sealed, high-quality, shatter-proof freezing containers and/or the application of a secondary enclosure such as "double bagging or straw in straw." A periodic disinfection of cryo-dewars should be considered as an additional precaution to diminish the potential for inadvertent cross-contamination. It might be advisable to use separate LN dewars to quarantine embryos derived from infected donors of valuable genotype or from unknown health status, extinction-threatened species. Nevertheless, in summary, it has been concluded that over 25 yr with no direct evidence of disease transmission by transferred cryopreserved human and animal embryos, that the present cryopreservation technology is sanitary sound, with the stipulation that biocontainment measures recommended by the International Embryo Transfer Society (IETS) and the World Organization for Animal Health - Office International des Epizooties (OIE), are strictly followed. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  15. Tunnel barrier schottky

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Rongming; Cao, Yu; Li, Zijian; Williams, Adam J.

    2018-02-20

    A diode includes: a semiconductor substrate; a cathode metal layer contacting a bottom of the substrate; a semiconductor drift layer on the substrate; a graded aluminum gallium nitride (AlGaN) semiconductor barrier layer on the drift layer and having a larger bandgap than the drift layer, the barrier layer having a top surface and a bottom surface between the drift layer and the top surface, the barrier layer having an increasing aluminum composition from the bottom surface to the top surface; and an anode metal layer directly contacting the top surface of the barrier layer.

  16. Barriers to Condom Use among High Risk Men Who Have Sex with Men in Uganda: A Qualitative Study.

    Science.gov (United States)

    Musinguzi, Geofrey; Bastiaens, Hilde; Matovu, Joseph K B; Nuwaha, Fred; Mujisha, Geoffrey; Kiguli, Juliet; Arinaitwe, Jim; Van Geertruyden, Jean-Pierre; Wanyenze, Rhoda K

    2015-01-01

    Unprotected sexual intercourse is a major risk factor for HIV transmission. Men who have sex with men (MSM) face challenges in accessing HIV prevention services, including condoms. However, there is limited in-depth assessment and documentation of the barriers to condom use among MSM in sub-Saharan Africa. In this paper, we examine the barriers to condom use among MSM in Uganda. The data for this study were extracted from a larger qualitative study conducted among 85 self-identified adult (>18 years) MSM in 11 districts in Uganda between July and December 2013. Data on sexual behaviours and access and barriers to condom use were collected using semi-structured interviews. All interviews were audio-recorded and transcribed verbatim. This paper presents an analysis of data for 33 MSM who did not use condoms at last sex, with a focus on barriers to condom use. Analysis was conducted using the content analysis approach. Six major barriers to condom use were identified: Difficulties with using condoms, access challenges, lack of knowledge and misinformation about condom use, partner and relationship related issues, financial incentives and socio-economic vulnerability, and alcohol consumption. The findings suggest that several reasons account for lack of condom use among high-risk MSM. The findings are valuable to inform interventions needed to increase condom use among MSM.

  17. Barriers to Condom Use among High Risk Men Who Have Sex with Men in Uganda: A Qualitative Study.

    Directory of Open Access Journals (Sweden)

    Geofrey Musinguzi

    Full Text Available Unprotected sexual intercourse is a major risk factor for HIV transmission. Men who have sex with men (MSM face challenges in accessing HIV prevention services, including condoms. However, there is limited in-depth assessment and documentation of the barriers to condom use among MSM in sub-Saharan Africa. In this paper, we examine the barriers to condom use among MSM in Uganda.The data for this study were extracted from a larger qualitative study conducted among 85 self-identified adult (>18 years MSM in 11 districts in Uganda between July and December 2013. Data on sexual behaviours and access and barriers to condom use were collected using semi-structured interviews. All interviews were audio-recorded and transcribed verbatim. This paper presents an analysis of data for 33 MSM who did not use condoms at last sex, with a focus on barriers to condom use. Analysis was conducted using the content analysis approach.Six major barriers to condom use were identified: Difficulties with using condoms, access challenges, lack of knowledge and misinformation about condom use, partner and relationship related issues, financial incentives and socio-economic vulnerability, and alcohol consumption.The findings suggest that several reasons account for lack of condom use among high-risk MSM. The findings are valuable to inform interventions needed to increase condom use among MSM.

  18. Oscillatory dependence of tunneling conductance on the barrier thickness

    Science.gov (United States)

    Lee, B. C.

    2017-11-01

    Oscillatory dependence of tunneling conductance on the barrier thickness is investigated theoretically for the metal/insulator/metal junctions. The tunneling transmission is expressed with the reflection and the transmission amplitudes of each separated metal/insulator interface and the wavevectors inside the barrier. An analytical formula is obtained for the tunneling conductance. The oscillatory behavior of the tunneling conductance is possible with the complex band structure of the insulator. The oscillation period is determined not directly from the real part of the complex wavevector in the insulator, but from the extremal complex spanning vector of the complex Fermi surface of the insulator.

  19. Transforming Education: Overcoming Barriers.

    Science.gov (United States)

    David, Jane L.; Goren, Paul D.

    Barriers to progress in educational reform exist inside and outside the education system. Some arise where new practices encounter traditional expectations and boundaries, but others go much deeper than education, such as poverty, racism, local political conflicts, and human resistance to change. The following five categories of barriers are…

  20. The automotive transmission book

    CERN Document Server

    Fischer, Robert; Jürgens, Gunter; Najork, Rolf; Pollak, Burkhard

    2015-01-01

    This book presents essential information on systems and interactions in automotive transmission technology and outlines the methodologies used to analyze and develop transmission concepts and designs. Functions of and interactions between components and subassemblies of transmissions are introduced, providing a basis for designing transmission systems and for determining their potentials and properties in vehicle-specific applications: passenger cars, trucks, buses, tractors, and motorcycles. With these fundamentals the presentation provides universal resources for both state-of-the-art and future transmission technologies, including systems for electric and hybrid electric vehicles.

  1. Catalytic thermal barrier coatings

    Science.gov (United States)

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  2. Automated manual transmission controller

    Science.gov (United States)

    Lawrie, Robert E.; Reed, Jr., Richard G.; Bernier, David R.

    1999-12-28

    A powertrain system for a hybrid vehicle. The hybrid vehicle includes a heat engine, such as a diesel engine, and an electric machine, which operates as both an electric motor and an alternator, to power the vehicle. The hybrid vehicle also includes a manual-style transmission configured to operate as an automatic transmission from the perspective of the driver. The engine and the electric machine drive an input shaft which in turn drives an output shaft of the transmission. In addition to driving the transmission, the electric machine regulates the speed of the input shaft in order to synchronize the input shaft during either an upshift or downshift of the transmission by either decreasing or increasing the speed of the input shaft. When decreasing the speed of the input shaft, the electric motor functions as an alternator to produce electrical energy which may be stored by a storage device. Operation of the transmission is controlled by a transmission controller which receives input signals and generates output signals to control shift and clutch motors to effect smooth launch, upshift shifts, and downshifts of the transmission, so that the transmission functions substantially as an automatic transmission from the perspective of the driver, while internally substantially functioning as a manual transmission.

  3. Plasmodium vivax Transmission in Africa.

    Directory of Open Access Journals (Sweden)

    Rosalind E Howes

    2015-11-01

    Full Text Available Malaria in sub-Saharan Africa has historically been almost exclusively attributed to Plasmodium falciparum (Pf. Current diagnostic and surveillance systems in much of sub-Saharan Africa are not designed to identify or report non-Pf human malaria infections accurately, resulting in a dearth of routine epidemiological data about their significance. The high prevalence of Duffy negativity provided a rationale for excluding the possibility of Plasmodium vivax (Pv transmission. However, review of varied evidence sources including traveller infections, community prevalence surveys, local clinical case reports, entomological and serological studies contradicts this viewpoint. Here, these data reports are weighted in a unified framework to reflect the strength of evidence of indigenous Pv transmission in terms of diagnostic specificity, size of individual reports and corroboration between evidence sources. Direct evidence was reported from 21 of the 47 malaria-endemic countries studied, while 42 countries were attributed with infections of visiting travellers. Overall, moderate to conclusive evidence of transmission was available from 18 countries, distributed across all parts of the continent. Approximately 86.6 million Duffy positive hosts were at risk of infection in Africa in 2015. Analysis of the mechanisms sustaining Pv transmission across this continent of low frequency of susceptible hosts found that reports of Pv prevalence were consistent with transmission being potentially limited to Duffy positive populations. Finally, reports of apparent Duffy-independent transmission are discussed. While Pv is evidently not a major malaria parasite across most of sub-Saharan Africa, the evidence presented here highlights its widespread low-level endemicity. An increased awareness of Pv as a potential malaria parasite, coupled with policy shifts towards species-specific diagnostics and reporting, will allow a robust assessment of the public health

  4. Shakeoff Ionization near the Coulomb Barrier Energy

    Science.gov (United States)

    Sharma, Prashant; Nandi, T.

    2017-11-01

    We measure the projectile K x-ray spectra as a function of the beam energies around the Coulomb barrier in different collision systems. The energy is scanned in small steps around the barrier aiming to explore the nuclear effects on the elastically scattered projectile ions. The variation of the projectile x-ray energy with the ion-beam energies exhibits an unusual increase in between the interaction barrier and fusion barrier energies. This additional contribution to the projectile ionization can be attributed to the shakeoff of outer-shell electrons of the projectile ions due to the sudden nuclear recoil (˜10-21 sec ) caused by the attractive nuclear potential, which gets switched on near the interaction barrier energy. In the sudden approximation limit, the theoretical shakeoff probability calculation due to the nuclear recoil explains the observed data well. In addition to its fundamental interest, such processes can play a significant role in dark matter detection through the possible mechanism of x-ray emissions, where the weakly interacting massive particle-nucleus elastic scattering can lead to the nuclear-recoil-induced inner-shell vacancy creations. Furthermore, the present work may provide new prospects for atomic physics research at barrier energies as well as provide a novel technique to perform barrier distribution studies for two-body systems.

  5. Breast cancer screening barriers and disability.

    Science.gov (United States)

    Todd, Ana; Stuifbergen, Alexa

    2012-01-01

    There is evidence that early detection from breast cancer screening is an effective means to reduce overall mortality from breast cancer. Findings from multiple research studies suggest that women with chronic disabling conditions are less likely to participate in breast cancer screening due to the multiple barriers they face. Barriers include those related to finances, environment, physical limitations, health carers' attitudes and lack of knowledge, and psychosocial issues. The purpose of this article is to provide an overview of the existing evidence of the barriers to breast cancer screening experienced by women with physical disabilities. Rehabilitation nurses that work with women who have chronic disabling conditions can be instrumental in eliminating these barriers to breast cancer screening through their efforts to promote health which is consistent with the philosophy of maximizing the health potential and quality of life of these women whose needs are often overlooked. © 2012 Association of Rehabilitation Nurses.

  6. Devices for overcoming biological barriers: the use of physical forces to disrupt the barriers.

    Science.gov (United States)

    Mitragotri, Samir

    2013-01-01

    Overcoming biological barriers including skin, mucosal membranes, blood brain barrier as well as cell and nuclear membrane constitutes a key hurdle in the field of drug delivery. While these barriers serve the natural protective function in the body, they limit delivery of drugs into the body. A variety of methods have been developed to overcome these barriers including formulations, targeting peptides and device-based technologies. This review focuses on the use of physical methods including acoustic devices, electric devices, high-pressure devices, microneedles and optical devices for disrupting various barriers in the body including skin and other membranes. A summary of the working principles of these devices and their ability to enhance drug delivery is presented. Copyright © 2012. Published by Elsevier B.V.

  7. Vehicle barrier systems

    International Nuclear Information System (INIS)

    Sena, P.A.

    1986-01-01

    The ground vehicle is one of the most effective tools available to an adversary force. Vehicles can be used to penetrate many types of perimeter barriers, transport equipment and personnel rapidly over long distances, and deliver large amounts of explosives directly to facilities in suicide missions. The function of a vehicle barrier system is to detain or disable a defined threat vehicle at a selected distance from a protected facility. Numerous facilities are installing, or planning to install, vehicle barrier systems and many of these facilities are requesting guidance to do so adequately. Therefore, vehicle barriers are being evaluated to determine their stopping capabilities so that systems can be designed that are both balanced and capable of providing a desired degree of protection. Equally important, many of the considerations that should be taken into account when establishing a vehicle barrier system have been identified. These considerations which pertain to site preparation, barrier selection, system integration and operation, and vehicle/barrier interaction, are discussed in this paper

  8. Improved performance thermal barrier coatings

    International Nuclear Information System (INIS)

    Levine, S.R.; Miller, R.A.; Stecura, S.

    1983-01-01

    Thermal barrier coatings offer an attractive approach to improving the durability and efficiency of the hot section of heat engines. The coatings typically consist of an inner alloy bond coating about 0.01 cm thick resistant to oxidation and hot corrosion and an outer ceramic layer, usually a stabilized zirconia, 0.01-0.05 cm thick. Here, the materials, thermomechanical stress, and hot corrosion problems associated with thermal barrier coatings are reviewed along with the capabilities and limitations of current technology. The coatings discussed include ZrO2-Y2O3/NiCrAlY, ZrO2-Y2O3/NiCoCrAlY, ZrO2-MgO/NiCoCrAlY, CaO-SiO2/Co-Cr-Al-Y, and CaO-SiO2/NiCrAlY systems. It is emphasized that the performance of thermal barrier coatings is governed by many complex and interrelated factors, so that optimization of these coatings always involves certain tradeoffs. 27 references

  9. Renewable Energy Zone (REZ) Transmission Planning Process: A Guidebook for Practitioners

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Nathan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Flores-Espino, Francisco [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hurlbut, David J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-05

    Achieving clean energy goals may require new investments in transmission, especially if planners anticipate economic growth and increased demand for electricity. The renewable energy zone (REZ) transmission planning process can help policymakers ensure their infrastructure investments achieve national goals in the most economical manner. Policymakers, planners, and system operators around the world have used variations of the REZ process to chart the expansion of their transmission networks and overcome the barriers of traditional transmission planning. This guidebook seeks to help power system planners, key decision makers, and stakeholders understand and use the REZ transmission planning process to integrate transmission expansion planning and renewable energy generation planning.

  10. Recycler barrier RF buckets

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C.M.; /Fermilab

    2011-03-01

    The Recycler Ring at Fermilab uses a barrier rf systems for all of its rf manipulations. In this paper, I will give an overview of historical perspective on barrier rf system, the longitudinal beam dynamics issues, aspects of rf linearization to produce long flat bunches and methods used for emittance measurements of the beam in the RR barrier rf buckets. Current rf manipulation schemes used for antiproton beam stacking and longitudinal momentum mining of the RR beam for the Tevatron collider operation are explained along with their importance in spectacular success of the Tevatron luminosity performance.

  11. Converse Barrier Certificate Theorem

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2013-01-01

    This paper presents a converse barrier certificate theorem for a generic dynamical system.We show that a barrier certificate exists for any safe dynamical system defined on a compact manifold. Other authors have developed a related result, by assuming that the dynamical system has no singular...... points in the considered subset of the state space. In this paper, we redefine the standard notion of safety to comply with generic dynamical systems with multiple singularities. Afterwards, we prove the converse barrier certificate theorem and illustrate the differences between ours and previous work...

  12. Converse Barrier Certificate Theorems

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2016-01-01

    This paper shows that a barrier certificate exists for any safe dynamical system. Specifically, we prove converse barrier certificate theorems for a class of structurally stable dynamical systems. Other authors have developed a related result by assuming that the dynamical system has neither...... singular points nor closed orbits. In this paper, we redefine the standard notion of safety to comply with dynamical systems with multiple singular elements. Hereafter, we prove the converse barrier certificate theorems and highlight the differences between our results and previous work by a number...

  13. Electromagnetic Transmission Through Resonant Structures

    Science.gov (United States)

    Young, Steven M.

    Electromagnetic resonators store energy in the form of oscillatory electric and magnetic fields and gradually exchange that energy by coupling with their environment. This coupling process can have profound effects on the transmission and reflection properties of nearby interfaces, with rapid transitions from high transmittance to high reflectance over narrow frequency ranges, and has been exploited to design useful optical components such as spectral filters and dielectric mirrors. This dissertation includes analytic, numeric, and experimental investigations of three different electromagnetic resonators, each based on a different method of confining electromagnetic fields near the region of interest. First, we show that a structure with two parallel conducting plates, each containing a subwavelength slit, supports a localized resonant mode bound to the slits and therefore exhibits (in the absence of nonradiative losses), perfect resonant transmission over a narrow frequency range. In practice, the transmission is limited by conduction losses in the sidewalls; nevertheless, experimental results at 10 GHz show a narrowband transmission enhancement by a factor of 104 compared to the non-resonant transmission, with quality factor (ratio of frequency to peak width) Q ~ 3000. Second, we describe a narrowband transmission filter based on a single-layer dielectric grating. We use a group theory analysis to show that, due to their symmetry, several of the grating modes cannot couple to light at normal incidence, while several others have extremely large coupling. We then show how selectively breaking the system symmetry using off-normal light incidence can produce transmission peaks by enabling weak coupling to some of the previously protected modes. The narrowband filtering capabilities are validated by an experimental demonstration in the long wavelength infrared, showing transmission peaks of quality factor Q ~ 100 within a free-spectral range of 8-15 mum. Third, we

  14. Revival of cloaking effect in a driven bilayer graphene vector barrier

    Science.gov (United States)

    Maiti, S.; Panigrahi, A.; Biswas, R.; Sinha, C.

    2018-05-01

    Transmission profiles in bilayer graphene are studied theoretically through a rectangular vector potential (magnetic) barrier with and without the presence of an oscillatory potential. Unlike the electrostatic barrier, the Fano resonances (FR) are noted in the transmission spectra both for normal and glancing incidences due to non-conservation of chirality for a static vector barrier. The results for normal incidence indicate that the cloaking effect is a manifestation of the chirality conservation in charge transport through bilayer graphene scalar barriers. It is also noted that the aforesaid FR for a static vector barrier might disappear (photon induced electronic cloaking effect) due to the predominant photon exchange processes in presence of an external oscillating potential. The study of Fano resonances in transmission spectrum is in high demand in respect of localization of charge carriers in graphene nano structures for its potential applications in digital device fabrications.

  15. Permanent isolation surface barrier development plan

    Energy Technology Data Exchange (ETDEWEB)

    Wing, N.R.

    1994-01-01

    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no {open_quotes}proven{close_quotes} long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems.

  16. Effectiveness of infection prevention measures featuring advanced source control and environmental cleaning to limit transmission of extremely-drug resistant Acinetobacter baumannii in a Thai intensive care unit: An analysis before and after extensive flooding.

    Science.gov (United States)

    Apisarnthanarak, Anucha; Pinitchai, Uayporn; Warachan, Boonyasit; Warren, David K; Khawcharoenporn, Thana; Hayden, Mary K

    2014-02-01

    Advanced source control (once-daily bathing and 4-times daily oral care with chlorhexidine aqueous solution) and thorough environmental cleaning were implemented in response to an increased incidence of colonization and infection with extremely drug-resistant (XDR) Acinetobacter baumannii in a Thai medical intensive care unit (MICU). During the 12-month baseline period (P1), contact isolation, active surveillance for XDR A baumannii, cohorting of XDR A baumannii patients, twice-daily environmental cleaning with detergent-disinfectant, and antibiotic stewardship were implemented. In the 5.5-month intervention period (P2), additional measures were introduced. Sodium hypochlorite was substituted for detergent-disinfectant, and advanced source control was implemented. All interventions except cleaning with sodium hypochlorite were continued during the 12.5-month follow-up period (P3). Extensive flooding necessitating closure of the hospital for 2 months occurred between P2 and P3. A total of 1,365 patients were studied. Compared with P1 (11.1 cases/1,000 patient-days), the rate of XDR A baumannii clinical isolates declined in P2 (1.74 cases/1,000 patient-days; P control and thorough environmental cleaning to limit colonization and infection with XDR A baumannii in MICUs in resource-limited settings. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  17. Optimistic barrier synchronization

    Science.gov (United States)

    Nicol, David M.

    1992-01-01

    Barrier synchronization is fundamental operation in parallel computation. In many contexts, at the point a processor enters a barrier it knows that it has already processed all the work required of it prior to synchronization. The alternative case, when a processor cannot enter a barrier with the assurance that it has already performed all the necessary pre-synchronization computation, is treated. The problem arises when the number of pre-sychronization messages to be received by a processor is unkown, for example, in a parallel discrete simulation or any other computation that is largely driven by an unpredictable exchange of messages. We describe an optimistic O(log sup 2 P) barrier algorithm for such problems, study its performance on a large-scale parallel system, and consider extensions to general associative reductions as well as associative parallel prefix computations.

  18. Barrier Infrared Detector (BIRD)

    Data.gov (United States)

    National Aeronautics and Space Administration — A recent breakthrough in MWIR detector design, has resulted in a high operating temperature (HOT) barrier infrared detector (BIRD) that is capable of spectral...

  19. Drivers of Tuberculosis Transmission.

    Science.gov (United States)

    Mathema, Barun; Andrews, Jason R; Cohen, Ted; Borgdorff, Martien W; Behr, Marcel; Glynn, Judith R; Rustomjee, Roxana; Silk, Benjamin J; Wood, Robin

    2017-11-03

    Measuring tuberculosis transmission is exceedingly difficult, given the remarkable variability in the timing of clinical disease after Mycobacterium tuberculosis infection; incident disease can result from either a recent (ie, weeks to months) or a remote (ie, several years to decades) infection event. Although we cannot identify with certainty the timing and location of tuberculosis transmission for individuals, approaches for estimating the individual probability of recent transmission and for estimating the fraction of tuberculosis cases due to recent transmission in populations have been developed. Data used to estimate the probable burden of recent transmission include tuberculosis case notifications in young children and trends in tuberculin skin test and interferon γ-release assays. More recently, M. tuberculosis whole-genome sequencing has been used to estimate population levels of recent transmission, identify the distribution of specific strains within communities, and decipher chains of transmission among culture-positive tuberculosis cases. The factors that drive the transmission of tuberculosis in communities depend on the burden of prevalent tuberculosis; the ways in which individuals live, work, and interact (eg, congregate settings); and the capacity of healthcare and public health systems to identify and effectively treat individuals with infectious forms of tuberculosis. Here we provide an overview of these factors, describe tools for measurement of ongoing transmission, and highlight knowledge gaps that must be addressed. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  20. Selected socioeconomic barriers of education in Sub-Saharan Africa

    OpenAIRE

    Tillová, Petra

    2015-01-01

    Selected socioeconomic barriers of education in Sub-Saharan Africa Abstract The aim of bachelor thesis is to describe and understand the process of education in Sub-Saharan Africa and analyze components that cause limited access to education. The first part of the thesis describes the process of education in Sub-Saharan Africa using selected indicators. The second main part focuses on the description and possible relations between selected socioeconomic barriers and literacy. Selected barrier...

  1. Wave attenuation over the Great Barrier Reef matrix

    NARCIS (Netherlands)

    Gallop, S.; Young, I.; Ranasinghe, Ranasinghe W M R J B; Durrant, T.; Haigh, I.; Mynett, Arthur

    2015-01-01

    This is the first large-scale study of the influence of an offshore reef matrix on wave transmission. The focus was on the Great Barrier Reef (GBR), Australia, utilizing a 16 yr-record of wave height, from seven satellite altimeters. Within the GBR matrix, wave height is not strongly dependent on

  2. Design of patient-specific focused ultrasound arrays for non-invasive brain therapy with increased trans-skull transmission and steering range

    Science.gov (United States)

    Hughes, Alec; Hynynen, Kullervo

    2017-09-01

    The use of a phased array of ultrasound transducer elements to sonicate through the skull has opened the way for new treatments and the delivery of therapeutics beyond the blood-brain barrier. The limited steering range of current clinical devices, particularly at higher frequencies, limits the regions of the brain that are considered treatable by ultrasound. A new array design is introduced that allows for high levels of beam steering and increased transmission throughout the brain. These improvements are achieved using concave transducers normal to the outer-skull surface in a patient-specific configuration to target within the skull, so that the far-field of each beam is within the brain. It is shown that by using pulsed ultrasound waves timed to arrive in-phase at the desired target, sufficient levels of acoustic energy are delivered for blood-brain barrier opening throughout the brain.

  3. Barriers of Adopting Environmental Management Practices in the Micro and Small Island Chalets Operation

    Directory of Open Access Journals (Sweden)

    Mariam Jamaludin

    2016-01-01

    Full Text Available Sustainability becomes main management issues for hospitality firms. Big hospitality firms conduct countless attempts to accommodate into the sustainability agenda. However, the small hospitality firms are left behind. The reason is some barriers that are dragging them. Barriers studies regarding big hospitality companies are plenteous. However, studies regarding barriers of MSIC operators are limited in Malaysia. Therefore, the objectives are to identify the barriers and the ranking of the barriers. This study is applying the quantitative and qualitative approach. The finding shows that lack of green products is the most salient barrier. In conclusion, this study has managed to identify barriers and provide some recommendations.

  4. Barriers to condom use: results from a study in Mumbai (Bombay), India.

    Science.gov (United States)

    Roth, J; Krishnan, S P; Bunch, E

    2001-02-01

    The consistent and correct use of condoms coupled with risk reduction education strategies, continue to play an important role in the reduction and prevention of HIV/AIDS transmission. Therefore understanding and incorporating strategies to overcome barriers to condom use in such education and prevention efforts are critical. This is particularly necessary in countries such as India, where HIV/AIDS has become a serious public health crisis. The current study documents and provides preliminary data on the use of condoms, reasons for and barriers to condom use, and sources of information about safer sex practices among a sexually active adult sample of 49 women and 203 men in Mumbai, India. Despite limitations such as the use of a nonrandom sample of participants composed predominantly of young, English-speaking males, the study findings provide some insights into the importance of and the need to address issues of privacy regarding condom purchase and use in India. Most notably, the lack of privacy in stores and the social stigma associated with condom use were indicated as the most significant barriers. These and other study findings suggest the need to ease the social costs and constraints to safe behaviors through increased acceptance of condoms and promotion of their consistent use. This could serve as an important means to curb the epidemic of HIV/AIDS in India.

  5. Lifetime Modeling of Thermal Barrier Coatings

    NARCIS (Netherlands)

    Hille, T.S.

    2009-01-01

    Thermal barrier coatings (TBCs) are applied in gas turbines to enhance their thermal efficiency by isolating the metallic components from the aggressive hot gas. TBC lifetime is limited by damage processes originating at internal interfaces, which may ultimately lead to delamination and spallation.

  6. Cultural Transmission of Civicness

    DEFF Research Database (Denmark)

    Ljunge, Jan Martin

    2012-01-01

    This paper estimates the intergeneration transmission of civicness by studying second generation immigrants in 29 European countries with ancestry in 83 nations. There is significant transmission of civicness both on the mother’s and the father’s side. The estimates are quantitatively significant...

  7. Cultural Transmission of Civicness

    DEFF Research Database (Denmark)

    Ljunge, Jan Martin

    This paper estimates the intergeneration transmission of civicness by studying second generation immigrants in 29 European countries with ancestry in 83 nations. There is significant transmission of civicness both on the mother’s and the father’s side. The estimates are quantitatively significant...

  8. Charge transmission through liquid neon and helium surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Galea, R [Nevis Laboratories, Columbia University, 136 South Broadway, P.O.Box 137, Irvington, NY, 10533 (United States); Dodd, J [Nevis Laboratories, Columbia University, 136 South Broadway, P.O.Box 137, Irvington, NY, 10533 (United States); Leltchouk, M [Nevis Laboratories, Columbia University, 136 South Broadway, P.O.Box 137, Irvington, NY, 10533 (United States); Willis, W [Nevis Laboratories, Columbia University, 136 South Broadway, P.O.Box 137, Irvington, NY, 10533 (United States); Rehak, P [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY, 11973 (United States); Tcherniatine, V [Brookhaven National Laboratory, P.O. Box 5000, Upton, NY, 11973 (United States)

    2007-04-15

    The transmission of charges through liquid neon and helium surfaces was studied. It was found that the penetration of charges from the liquid to the gas phase is more complex than a simple barrier penetration. The effective surface trapping times of localized electrons in liquid neon is much longer than previously measured.

  9. Charge transmission through liquid neon and helium surfaces

    Science.gov (United States)

    Galea, R.; Dodd, J.; Leltchouk, M.; Willis, W.; Rehak, P.; Tcherniatine, V.

    2007-04-01

    The transmission of charges through liquid neon and helium surfaces was studied. It was found that the penetration of charges from the liquid to the gas phase is more complex than a simple barrier penetration. The effective surface trapping times of localized electrons in liquid neon is much longer than previously measured.

  10. Investigating the status and barriers of science laboratory activities ...

    African Journals Online (AJOL)

    This study aims at investigating the barriers encountered by science teachers in laboratory activities in Rwandan teacher training colleges (TTCs) using questionnaires and interviews. The results confirmed that teachers face barriers like time limitation, material scarcity and lack of improvising skills in their everyday science ...

  11. On the nature of barriers to climate change adaptation

    NARCIS (Netherlands)

    Biesbroek, G.R.; Klostermann, J.E.M.; Termeer, C.J.A.M.; Kabat, P.

    2013-01-01

    Considerable barriers can emerge in developing and implementing climate change adaptation strategies. Understanding the nature of barriers to adaptation is important so as to find strategic ways of dealing with them. However, our current understanding is limited and highly fragmented across the

  12. The blood-brain barrier in migraine treatment

    DEFF Research Database (Denmark)

    Edvinsson, L.; Tfelt-Hansen, P.

    2008-01-01

    Salient aspects of the anatomy and function of the blood-barrier barrier (BBB) are reviewed in relation to migraine pathophysiology and treatment. The main function of the BBB is to limit the access of circulating substances to the neuropile. Smaller lipophilic substances have some access...

  13. Elements modulating the prion species barrier and its passage consequences.

    Directory of Open Access Journals (Sweden)

    Juan-Maria Torres

    Full Text Available The specific characteristics of Transmissible Spongiform Encephalopathy (TSE strains may be altered during passage across a species barrier. In this study we investigated the biochemical and biological characteristics of Bovine Spongiform Encephalopathy (BSE after transmission in both natural host species (cattle, sheep, pigs and mice and in transgenic mice overexpressing the corresponding cellular prion protein (PrPC in comparison with other non-BSE related prions from the same species. After these passages, most features of the BSE agent remained unchanged. BSE-derived agents only showed slight modifications in the biochemical properties of the accumulated PrPSc, which were demonstrated to be reversible upon re-inoculation into transgenic mice expressing bovine-PrPC. Transmission experiments in transgenic mice expressing bovine, porcine or human-PrP revealed that all BSE-derived agents were transmitted with no or a weak transmission barrier. In contrast, a high species barrier was observed for the non-BSE related prions that harboured an identical PrP amino acid sequence, supporting the theory that the prion transmission barrier is modulated by strain properties (presumably conformation-dependent rather than by PrP amino acid sequence differences between host and donor. As identical results were observed with prions propagated either in natural hosts or in transgenic mouse models, we postulate that the species barrier and its passage consequences are uniquely governed by the host PrPC sequence and not influenced by other host genetic factors. The results presented herein reinforce the idea that the BSE agent is highly promiscuous, infecting other species, maintaining its properties in the new species, and even increasing its capabilities to jump to other species including humans. These data are essential for the development of an accurate risk assessment for BSE.

  14. Elements Modulating the Prion Species Barrier and Its Passage Consequences

    Science.gov (United States)

    Torres, Juan-Maria; Espinosa, Juan-Carlos; Aguilar-Calvo, Patricia; Herva, María-Eugenia; Relaño-Ginés, Aroa; Villa-Diaz, Ana; Morales, Mónica; Parra, Beatriz; Alamillo, Elia; Brun, Alejandro; Castilla, Joaquín; Molina, Susana; Hawkins, Steve A. C.; Andreoletti, Olivier

    2014-01-01

    The specific characteristics of Transmissible Spongiform Encephalopathy (TSE) strains may be altered during passage across a species barrier. In this study we investigated the biochemical and biological characteristics of Bovine Spongiform Encephalopathy (BSE) after transmission in both natural host species (cattle, sheep, pigs and mice) and in transgenic mice overexpressing the corresponding cellular prion protein (PrPC) in comparison with other non-BSE related prions from the same species. After these passages, most features of the BSE agent remained unchanged. BSE-derived agents only showed slight modifications in the biochemical properties of the accumulated PrPSc, which were demonstrated to be reversible upon re-inoculation into transgenic mice expressing bovine-PrPC. Transmission experiments in transgenic mice expressing bovine, porcine or human-PrP revealed that all BSE-derived agents were transmitted with no or a weak transmission barrier. In contrast, a high species barrier was observed for the non-BSE related prions that harboured an identical PrP amino acid sequence, supporting the theory that the prion transmission barrier is modulated by strain properties (presumably conformation-dependent) rather than by PrP amino acid sequence differences between host and donor. As identical results were observed with prions propagated either in natural hosts or in transgenic mouse models, we postulate that the species barrier and its passage consequences are uniquely governed by the host PrPC sequence and not influenced by other host genetic factors. The results presented herein reinforce the idea that the BSE agent is highly promiscuous, infecting other species, maintaining its properties in the new species, and even increasing its capabilities to jump to other species including humans. These data are essential for the development of an accurate risk assessment for BSE. PMID:24608126

  15. An extreme breaching of a barrier spit: insights on large breach formation and its impact on barrier dynamics

    Science.gov (United States)

    Iulian Zăinescu, Florin; Vespremeanu-Stroe, Alfred; Tătui, Florin

    2017-04-01

    In this study, we document a case of exceptionally large natural breaching of a sandy spit (Sacalin barrier, Danube delta) using Lidar data and satellite imagery, annual (and seasonal) surveys of topography and bathymetry on successive cross-barrier profiles, and hourly datasets of wind and waves. The breach morphology and dynamics was monitored and described from its inception to closure, together with its impact on the adjoining features (upper shoreface, back-barrier lagoon, downdrift coast) and on the local sediment budgets. Breaching is first observed to occur on a beach-length of 0.5 km in April 2012 and two years later reached 3.5 km (May 2014). The barrier translates to a recovery stage dominated by continuous back-barrier deposition through subaqueous cross-breach sediment transport. Soon, the barrier widening triggers a negative feedback which limits the back-barrier sediment transfer. As a result, back-barrier deposition decreases whilst the barrier aggradation through overwash becomes more frequent. The event was found to be a natural experiment which switched the barrier's decadal evolution from low cross-shore transport to high cross-shore transport over the barrier. Although previously considered as constant, the cross-shore transport recorded during the large breach lifespan is an order of magnitude larger than in the non-breach period. 3 x 106 m3 of sediment were deposited in three years which is equivalent to the modelled longshore transport in the region. Nevertheless, the sediment circuits are more complex involving exchanges with the upper shoreface, as indicated by the extensive erosion down to -4m. In the absence of tides, the Sacalin breach closed naturally in 3 years and brings a valuable contribution on how breaches may evolve, as only limited data has been internationally reported until now. The very high deposition rate of sediment in the breach is a testimony of the high sediment volumes supplied by the longshore transport and the high

  16. Intestinal Barrier and Behavior.

    Science.gov (United States)

    Julio-Pieper, M; Bravo, J A

    2016-01-01

    The intestinal barrier function contributes to gut homeostasis by modulating absorption of water, electrolytes, and nutrients from the lumen into the circulation while restricting the passage of noxious luminal substances and microorganisms. Chronic conditions such as rheumatoid arthritis, inflammatory bowel disease, and celiac disease are associated to intestinal barrier dysfunction. Here, the hypothesis is that a leaky intestinal wall allowing for indiscriminate passage of intraluminal compounds to the vascular compartment could in turn lead to systemic inflammation. An increasing number of studies are now investigating the association between gut permeability and CNS disorders, under the premise that translocation of intestinal luminal contents could affect CNS function, either directly or indirectly. Still, it is unknown whether disruption of intestinal barrier is a causative agent or a consequence in these situations. Here, we discuss the latest evidence pointing to an association between increased gut permeability and disrupted behavioral responses. © 2016 Elsevier Inc. All rights reserved.

  17. Skin barrier in rosacea*

    Science.gov (United States)

    Addor, Flavia Alvim Sant'Anna

    2016-01-01

    Recent studies about the cutaneous barrier demonstrated consistent evidence that the stratum corneum is a metabolically active structure and also has adaptive functions, may play a regulatory role in the inflammatory response with activation of keratinocytes, angiogenesis and fibroplasia, whose intensity depends primarily on the intensity the stimulus. There are few studies investigating the abnormalities of the skin barrier in rosacea, but the existing data already show that there are changes resulting from inflammation, which can generate a vicious circle caused a prolongation of flare-ups and worsening of symptoms. This article aims to gather the most relevant literature data about the characteristics and effects of the state of the skin barrier in rosacea. PMID:26982780

  18. Health Barriers to Learning

    Directory of Open Access Journals (Sweden)

    Delaney Gracy

    2014-01-01

    Full Text Available This article summarizes the results from a 2013 online survey with 408 principals and assistant principals in New York City public elementary and middle schools. The survey assessed three primary areas: health issues in the school, health issues perceived as barriers to learning for affected students, and resources needed to address these barriers. Eighteen of the 22 health conditions listed in the survey were considered a moderate or serious issue within their schools by at least 10% of respondents. All 22 of the health issues were perceived as a barrier to learning by between 12% and 87% of the respondents. Representatives from schools that serve a higher percentage of low-income students reported significantly higher levels of concern about the extent of health issues and their impact on learning. Respondents most often said they need linkages with organizations that can provide additional services and resources at the school, especially for mental health.

  19. Effect of glove occlusion on the skin barrier

    DEFF Research Database (Denmark)

    Tiedemann, Daniel; Clausen, Maja Lisa; John, Swen Malthe

    2016-01-01

    that the negative effect of occlusion in itself is limited, and that only extensive and long-term occlusion will cause barrier impairment. However, studies investigating combined effect of occlusion and exposure to soaps/detergents indicate that occlusion significantly enhances the skin barrier damage caused...... of this study is to review the literature on the effects of glove occlusion on skin barrier function. The PubMed database was searched up to 1 February 2015 for articles on the association between glove occlusion and skin barrier function, including human studies only and in English. Only experimental studies...... by detergents/soaps in a dose-response fashion....

  20. Barrier transgression driven by aeolian processes along the Portuguese coast

    Science.gov (United States)

    Costas, Susana; Ferreira, Óscar; Roelvink, Dano

    2017-04-01

    Coastal barriers around the world developed following sea level stabilization about 7000 years ago. Along the Southwestern European coast, this fact was largely supported by recent works exploring the sedimentary record of coastal lagoons and estuaries. However, direct evidences of barrier evolution/age obtained from the actual coastal barriers are rare, limiting our understanding about the dynamics and life time of these systems at long time scales. Here, we reconstruct the evolution of three coastal barriers located along the western Portuguese coast, determining their age, trends and life cycles. For that, we integrate information (stratigraphy and ages) from different coastal deposits indicative of major shifts on evolutionary trends, including published and unpublished data. Examined beach deposits set the age of the explored sand barriers between 6400 and 300 years ago, suggesting the coexistence of very mature and very recent coastal barriers. In addition, the results document the occurrence of transgressive dunefields with ages older than the preserved coastal barriers, supporting the existence of former barriers from which the dunes could derive and migrate inland. The latter suggests the occurrence of episodes of barrier building and shoreline progradation alternating with episodes of inland migration of transgressive dunefields and thus barrier rollover. Resultant trends are carefully examined to identify the major factors driving barrier evolution, with special attention to climate variability and local boundary conditions. Indeed, the episodic response of the explored sand barriers provides indications for shifting wave and wind conditions as a consequence of climate variability. Additionally, inter-site comparison provides significant insights into regional trends and allows rating the identified factors, based on the degree of direct influence over the evolution of the coast. In this regard, the exposure to wind and wave climate, usually linked to

  1. Current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Loescher, D.H. [Sandia National Labs., Albuquerque, NM (United States). Systems Surety Assessment Dept.; Noren, K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering

    1996-09-01

    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  2. Understanding Ebola Virus Transmission

    Directory of Open Access Journals (Sweden)

    Seth Judson

    2015-02-01

    Full Text Available An unprecedented number of Ebola virus infections among healthcare workers and patients have raised questions about our understanding of Ebola virus transmission. Here, we explore different routes of Ebola virus transmission between people, summarizing the known epidemiological and experimental data. From this data, we expose important gaps in Ebola virus research pertinent to outbreak situations. We further propose experiments and methods of data collection that will enable scientists to fill these voids in our knowledge about the transmission of Ebola virus.

  3. Fault current limiter

    Science.gov (United States)

    Darmann, Francis Anthony

    2013-10-08

    A fault current limiter (FCL) includes a series of high permeability posts for collectively define a core for the FCL. A DC coil, for the purposes of saturating a portion of the high permeability posts, surrounds the complete structure outside of an enclosure in the form of a vessel. The vessel contains a dielectric insulation medium. AC coils, for transporting AC current, are wound on insulating formers and electrically interconnected to each other in a manner such that the senses of the magnetic field produced by each AC coil in the corresponding high permeability core are opposing. There are insulation barriers between phases to improve dielectric withstand properties of the dielectric medium.

  4. Transmission infrastructure development in Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Stubbings, R.V. [EnVision Energy Consulting Ltd., Calgary, AB (Canada)

    2004-09-01

    Major power blackouts have resulted in greater attention to reliability. Changes in industry structure have placed unanticipated demands on transmission systems. Load growth has outstripped transmission investment, and there are major implications for infrastructure development due to the enactment of the new transmission regulation. This paper discusses several projects addressing new developments in the electric power industry, including details of an Edmonton-Calgary path upgrade in order to increase north-south transmission capacity. Proposed southwest Transmission upgrades were reviewed, including the construction of a double-circuit 240 kV line from Pincher Creek to Peigan or Mud Lake, in order to improve reliability and improve access to southern wind and hydro generation. Other possible projects include a High Voltage Direct Current (HVDC) from Fort McMurray to Calgary and a Northern Lights Transmission project between Fort McMurray and the Pacific Northwest. Various investment drivers were reviewed, with oil sands processing providing steam hosts for cogeneration at Fort McMurray and Cold Lake generation as well as Lake Wabamun. Plans concerning Southwest Alberta generation were presented, including wind-powered generation, and load growth in southern Alberta. Various investment limiters include absorption of existing capacity; improved facility utilization; and distributed generation. Competition for investment funds were discussed, in addition to uncertainties over generation siting as well as regulatory difficulties and power flow pattern irregularities due to increasing market integration. Uncertain access to markets, locational marginal pricing and various southern Alberta generation incentives were reviewed. Market implications include generation mix; lower price volatility; reduced potential for market power abuse by generators; and increased export levels. The implications for British Columbia were highlighted, with particular reference to an

  5. Transmissions in vehicles 2010

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    Within the international VDI congress 'Gears in vehicles 2010' of the VDI Wissensforum GmbH (Duesseldorf, Federal Republic of Germany) between 22nd and 23rd June, 2010, in Friedrichshafen (Federal Republic of Germany), the following lectures were held: (1) 8HP70H - The moldhybrid transmission from ZF - Cjallenges and achievements (P. Gutmann); (2) GETRAG boosted range extender - A highly flexible electric powertrain for maximum CO{sub 2} reduction (S. Huepkes); (3) E-Transmission between full-hybrid and E-drive (P. Tenberge); (4) Reducing NO{sub x} and particulate emissions in electrified drivelines (R. Kuberczyk); (5) Simulation aided HEV and EV development: from the component to the whole powertrain (A. Gacometti); (6) Investigations on operating behaviour of the optimized CVT hybrid driveline (B.-R. Hoehn); (7) Customer-oriented dimensioning of electrified drivetrains (M. Eghtessad); (8) Decentralized optimal control strategy for parallel hybrid electric vehicles (A. Frenkel); (9) The new generation 6-speed automatic transmission AF40 (G. Bednarek); (10) Customized mechatronic solutions for integrated transmission control units (M. Wieczorek); (11) The optimal automatic transmission for front-transverse applications - Planetary transmissions or dual clutch transmissions? (G. Gumpoltsberger); (12) The new shift-by-wire gearshift lever for the Audi A8 - Requirements and concept (T. Guttenbergere); (13) The new shift-by-wire gearshift lever for the Audi A8 - Realization (A. Giefer); (14) Fuel-efficient transmissions of the future: Calculation of the efficiency factor for vehicle transmissions (B. Volpert); (15) HT-ACM: A new polymer generation for static and dynamic gearbox sealing solutions (E. Osen); (16) 'Energy efficiency equipped solutions by SKF' for power train applications - A contribution to CO{sub 2} - emission reduction and sustainability (T. Bobke); (17) 6-Ratio planetary shift transmission controlled by 4 external brakes, and design

  6. Kansas Electric Transmission Lines

    Data.gov (United States)

    Kansas Data Access and Support Center — This data set is a digital representation of the EletcircTransmission lines for the State of Kansas as maintained by the Kansas Corporation Commission. Data is...

  7. Transmission issues in Alberta

    International Nuclear Information System (INIS)

    Levson, D.

    2002-01-01

    This paper outlined the major issues and concerns facing users of the transmission system in Alberta. They include congestion management issues that make investors uncertain about power generation. It is necessary to know the difference between which transmission price signals will be faced by low cost cogeneration at Fort McMurray and Cold Lake coal-fired generation near Edmonton compared to combined cycle gas generation near Calgary. Import and export policy tariffs are another concern. Most new generation opportunities in Alberta require access to export markets, but transmission facilities for export need policy support and appropriate tariffs. It was noted that the past actions of Alberta's Transmission Administrator and balancing pool may be distorting market signals for ancillary service markets, and that loss studies and calculations need upgrading

  8. Electric Power Transmission Lines

    Data.gov (United States)

    Department of Homeland Security — Transmission Lines are the system of structures, wires, insulators and associated hardware that carry electric energy from one point to another in an electric power...

  9. Watching Handball Transmissions

    DEFF Research Database (Denmark)

    Frandsen, Kirsten

    2010-01-01

    The current article presents a qualitative study of Danish television viewer’s reception of Danish handball transmissions. The overall aim of the study has been to contribute to a more nuanced understanding of televised sport as a specific kind of television entertainment. The analysis shows that......, due to the dramaturgic structure of handball transmissions, viewers consider such transmissions particularly reliable and effective sources of entertainment. The transmissions’ entertainment value derives from their specific ability to give the viewers a complex experience of feeling autonomous...... and competent when mastering the game and in relation to others. The study shows that entertainment concerns both affective involvement and identity formation, as social and cultural meaning seem to be at the root of involvement. Even though both men and women find great joy in the transmissions, their viewing...

  10. Quench limits

    International Nuclear Information System (INIS)

    Sapinski, M.

    2012-01-01

    With thirteen beam induced quenches and numerous Machine Development tests, the current knowledge of LHC magnets quench limits still contains a lot of unknowns. Various approaches to determine the quench limits are reviewed and results of the tests are presented. Attempt to reconstruct a coherent picture emerging from these results is taken. The available methods of computation of the quench levels are presented together with dedicated particle shower simulations which are necessary to understand the tests. The future experiments, needed to reach better understanding of quench limits as well as limits for the machine operation are investigated. The possible strategies to set BLM (Beam Loss Monitor) thresholds are discussed. (author)

  11. Eliminating Perinatal HIV Transmission

    Centers for Disease Control (CDC) Podcasts

    2012-11-26

    In this podcast, CDC’s Dr. Steve Nesheim discusses perinatal HIV transmission, including the importance of preventing HIV among women, preconception care, and timely HIV testing of the mother. Dr. Nesheim also introduces the revised curriculum Eliminating Perinatal HIV Transmission intended for faculty of OB/GYN and pediatric residents and nurse midwifery students.  Created: 11/26/2012 by Division of HIV/AIDS Prevention.   Date Released: 11/26/2012.

  12. Crossing the Salt Barrier

    Indian Academy of Sciences (India)

    Fry. RIVER. To cross the salt barrier is, therefore, an obligatory part of every amphihaline fish cycle. Figure 2a. Life Cycle of. Salmon. Adult salmon migrate from sea towards the river. After reaching their hatching ground, the eggs are laid in the gravel. The spawned fishes are called kelts. Alevin is a stage from hatching to fry.

  13. Great Barrier Reef

    Science.gov (United States)

    2002-01-01

    A better than average view of the Great Barrier Reef was captured by SeaWiFS on a recent overpass. There is sunglint northeast of the reef and there appears to be some sort of filamentous bloom in the Capricorn Channel.

  14. National transmission grid study

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, Spencer [USDOE Office of the Secretary of Energy, Washington, DC (United States)

    2003-05-31

    The National Energy Policy Plan directed the U.S. Department of Energy (DOE) to conduct a study to examine the benefits of establishing a national electricity transmission grid and to identify transmission bottlenecks and measures to address them. DOE began by conducting an independent analysis of U.S. electricity markets and identifying transmission system bottlenecks using DOE’s Policy Office Electricity Modeling System (POEMS). DOE’s analysis, presented in Section 2, confirms the central role of the nation’s transmission system in lowering costs to consumers through increased trade. More importantly, DOE’s analysis also confirms the results of previous studies, which show that transmission bottlenecks and related transmission system market practices are adding hundreds of millions of dollars to consumers’ electricity bills each year. A more detailed technical overview of the use of POEMS is provided in Appendix A. DOE led an extensive, open, public input process and heard a wide range of comments and recommendations that have all been considered.1 More than 150 participants registered for three public workshops held in Detroit, MI (September 24, 2001); Atlanta, GA (September 26, 2001); and Phoenix, AZ (September 28, 2001).

  15. Sound trapping and dredging barriers.

    Science.gov (United States)

    Wang, Xu; Wang, Xiaonan; Yu, Wuzhou; Jiang, Zaixiu; Mao, Dongxing

    2017-06-01

    When sound barriers are installed on both sides of a noise source, degradation in performance is observed. Barriers having negative-phase-gradient surfaces successfully eliminate this drawback by trapping sound energy in between the barriers. In contrast, barriers can also be designed to "dredge" the energy flux out. An extended model considering higher-order diffractions, which resulted from the interplay of the induced surface wave and barrier surface periodicity, is presented. It is found that the sound dredging barriers provide a remarkable enhancement over the trapping ones, and hence have the potential to be widely used in noise control engineering.

  16. Dose limits

    International Nuclear Information System (INIS)

    Fitoussi, L.

    1987-12-01

    The dose limit is defined to be the level of harmfulness which must not be exceeded, so that an activity can be exercised in a regular manner without running a risk unacceptable to man and the society. The paper examines the effects of radiation categorised into stochastic and non-stochastic. Dose limits for workers and the public are discussed

  17. Foundations of noise barriers according to eurocode standards

    OpenAIRE

    Bajec, Andrej

    2011-01-01

    In this thesis, different types of noise barriers are presented. The focus in the thesis then shifts to a wall type barrier and its foundation. Following this are the calculations of the forces that are acting on the barrier and by extension on the foundation itself. A choice for the foundation is a concrete rectangular shaped foundation. All the necessary controls of the foundation are introduced on the ultimate limit state and serviceability limit state. Added to the thesis is a CD which co...

  18. Flexible Transmission in the Smart Grid

    Science.gov (United States)

    Hedman, Kory Walter

    There is currently a national push to create a smarter electric grid; introducing new technologies that will create a more controllable and flexible grid is part of the smart grid concept and integral to its success. The full control of transmission assets are not currently built into electric energy dispatch optimization models. Optimal transmission switching is a straightforward way to leverage grid controllability: to make better use of the existing system and meet growing demand with existing infrastructure. Previous research has shown that transmission switching as a corrective mechanism can help relieve line overloading, voltage violations, etc. However, there has been limited focus on the use of transmission switching as a means to improve the economic efficiency of the network by incorporating the control of transmission assets into the overall economic dispatch problem. This research discusses the ways that the modeling of flexible transmission assets can benefit the multi-trillion dollar electric industry. It presents and analyzes novel formulations by which the operator can incorporate this flexibility into the economic dispatch formulation. This research focuses on modeling transmission assets so that they can be temporarily taken out of service, i.e., by opening breakers, or kept in service, i.e., by keeping the breakers closed. By incorporating this control into the network optimization problem, this provides the ability for the operator to consider the state of a transmission line as a decision variable instead of treating it as a static asset, which is the current practice today. The possible benefits demonstrated from this research indicate that the benefits to society are substantial. On the contrary, the benefits to individual market participants are uncertain; some will benefit and other will not. Consequently, this research also analyzes the impacts that optimal transmission switching may have on market participants as well as the policy

  19. Lattice QCD without topology barriers

    CERN Document Server

    Lüscher, Martin

    2011-01-01

    As the continuum limit is approached, lattice QCD simulations tend to get trapped in the topological charge sectors of field space and may consequently give biased results in practice. We propose to bypass this problem by imposing open (Neumann) boundary conditions on the gauge field in the time direction. The topological charge can then flow in and out of the lattice, while many properties of the theory (the hadron spectrum, for example) are not affected. Extensive simulations of the SU(3) gauge theory, using the HMC and the closely related SMD algorithm, confirm the absence of topology barriers if these boundary conditions are chosen. Moreover, the calculated autocorrelation times are found to scale approximately like the square of the inverse lattice spacing, thus supporting the conjecture that the HMC algorithm is in the universality class of the Langevin equation.

  20. Analog data transmission via fiber optics

    International Nuclear Information System (INIS)

    Cisneros, E.L.; Burgueno, G.F.

    1986-10-01

    In the SLAC Linear Collider Detector (SLD), as in most high-energy particle detectors, the electromagnetic noise environment is the limiting factor in electronic readout performance. Front-end electronics are particulary susceptible to electromagnetic interference (EMI), and great care has been taken to minimize its effects. The transfer of preprocessed analog signals from the detector environs, to the remote digital processing electronics, by conventional means (via metal conductors), may ultimately limit the performance of the system. Because it is highly impervious to EMI and ground loops, a fiber-optic medium has been chosen for the transmission of these signals. This paper describes several fiber-optic transmission schemes which satisfy the requirements of the SLD analog data transmission

  1. Astrocytes optimize the synaptic transmission of information.

    Directory of Open Access Journals (Sweden)

    Suhita Nadkarni

    2008-05-01

    Full Text Available Chemical synapses transmit information via the release of neurotransmitter-filled vesicles from the presynaptic terminal. Using computational modeling, we predict that the limited availability of neurotransmitter resources in combination with the spontaneous release of vesicles limits the maximum degree of enhancement of synaptic transmission. This gives rise to an optimal tuning that depends on the number of active zones. There is strong experimental evidence that astrocytes that enwrap synapses can modulate the probabilities of vesicle release through bidirectional signaling and hence regulate synaptic transmission. For low-fidelity hippocampal synapses, which typically have only one or two active zones, the predicted optimal values lie close to those determined by experimentally measured astrocytic feedback, suggesting that astrocytes optimize synaptic transmission of information.

  2. Identification of Critical Transmission Limits in Injection Impedance Plane

    DEFF Research Database (Denmark)

    Jóhannsson, Hjörtur; Østergaard, Jacob; Nielsen, Arne Hejde

    2012-01-01

    the partial derivatives of the variables P,Q and V in respect to each other become zero. In addition to the mappingof the critical lines, some characteristic lines are mapped as well. These include the mapping of the lines of constant P,Q,Vand d from the PQV-surface into the impedance plane. All of the mapped...

  3. Limiting HIV Transmission through Screening and Treatment of High ...

    African Journals Online (AJOL)

    A significant epidemiologic feature of HIV/AIDS disease is the presence of an unsually long period of inapparent infection of 10-15 year during which the virus can be transmitted from person to person (1). During this phase infection is detectable only by HIV screening. An effective control program should include a strong ...

  4. Geophysical characterization of subsurface barriers

    International Nuclear Information System (INIS)

    Borns, D.J.

    1995-08-01

    An option for controlling contaminant migration from plumes and buried waste sites is to construct a subsurface barrier of a low-permeability material. The successful application of subsurface barriers requires processes to verify the emplacement and effectiveness of barrier and to monitor the performance of a barrier after emplacement. Non destructive and remote sensing techniques, such as geophysical methods, are possible technologies to address these needs. The changes in mechanical, hydrologic and chemical properties associated with the emplacement of an engineered barrier will affect geophysical properties such a seismic velocity, electrical conductivity, and dielectric constant. Also, the barrier, once emplaced and interacting with the in situ geologic system, may affect the paths along which electrical current flows in the subsurface. These changes in properties and processes facilitate the detection and monitoring of the barrier. The approaches to characterizing and monitoring engineered barriers can be divided between (1) methods that directly image the barrier using the contrasts in physical properties between the barrier and the host soil or rock and (2) methods that reflect flow processes around or through the barrier. For example, seismic methods that delineate the changes in density and stiffness associated with the barrier represents a direct imaging method. Electrical self potential methods and flow probes based on heat flow methods represent techniques that can delineate the flow path or flow processes around and through a barrier

  5. Elastically frustrated rehybridization: Origin of chemical order and compositional limits in InGaN quantum wells

    Science.gov (United States)

    Lymperakis, L.; Schulz, T.; Freysoldt, C.; Anikeeva, M.; Chen, Z.; Zheng, X.; Shen, B.; Chèze, C.; Siekacz, M.; Wang, X. Q.; Albrecht, M.; Neugebauer, J.

    2018-01-01

    Nominal InN monolayers grown by molecular beam epitaxy on GaN(0001) are investigated combining in situ reflection high-energy electron diffraction (RHEED), transmission electron microscopy (TEM), and density functional theory (DFT). TEM reveals a chemical intraplane ordering never observed before. Employing DFT, we identify a novel surface stabilization mechanism elastically frustrated rehybridization, which is responsible for the observed chemical ordering. The mechanism also sets an incorporation barrier for indium concentrations above 25% and thus fundamentally limits the indium content in coherently strained layers.

  6. Inverse Limits

    CERN Document Server

    Ingram, WT

    2012-01-01

    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  7. Priority image transmission in wireless sensor networks

    International Nuclear Information System (INIS)

    Nasri, M.; Helali, A.; Sghaier, H.; Maaref, H.

    2011-01-01

    The emerging technology during the last years allowed the development of new sensors equipped with wireless communication which can be organized into a cooperative autonomous network. Some application areas for wireless sensor networks (WSNs) are home automations, health care services, military domain, and environment monitoring. The required constraints are limited capacity of processing, limited storage capability, and especially these nodes are limited in energy. In addition, such networks are tiny battery powered which their lifetime is very limited. During image processing and transmission to the destination, the lifetime of sensor network is decreased quickly due to battery and processing power constraints. Therefore, digital image transmissions are a significant challenge for image sensor based Wireless Sensor Networks (WSNs). Based on a wavelet image compression, we propose a novel, robust and energy-efficient scheme, called Priority Image Transmission (PIT) in WSN by providing various priority levels during image transmissions. Different priorities in the compressed image are considered. The information for the significant wavelet coeffcients are transmitted with higher quality assurance, whereas relatively less important coefficients are transmitted with lower overhead. Simulation results show that the proposed scheme prolongs the system lifetime and achieves higher energy efficiency in WSN with an acceptable compromise on the image quality.

  8. Quantum Transmission Conditions for Diffusive Transport in Graphene with Steep Potentials

    Science.gov (United States)

    Barletti, Luigi; Negulescu, Claudia

    2018-05-01

    We present a formal derivation of a drift-diffusion model for stationary electron transport in graphene, in presence of sharp potential profiles, such as barriers and steps. Assuming the electric potential to have steep variations within a strip of vanishing width on a macroscopic scale, such strip is viewed as a quantum interface that couples the classical regions at its left and right sides. In the two classical regions, where the potential is assumed to be smooth, electron and hole transport is described in terms of semiclassical kinetic equations. The diffusive limit of the kinetic model is derived by means of a Hilbert expansion and a boundary layer analysis, and consists of drift-diffusion equations in the classical regions, coupled by quantum diffusive transmission conditions through the interface. The boundary layer analysis leads to the discussion of a four-fold Milne (half-space, half-range) transport problem.

  9. Apoplastic Diffusion Barriers in Arabidopsis

    Science.gov (United States)

    Schreiber, Lukas; Franke, Rochus Benni; Geldner, Niko; Reina-Pinto, José J.; Kunst, Ljerka

    2013-01-01

    During the development of Arabidopsis and other land plants, diffusion barriers are formed in the apoplast of specialized tissues within a variety of plant organs. While the cuticle of the epidermis is the primary diffusion barrier in the shoot, the Casparian strips and suberin lamellae of the endodermis and the periderm represent the diffusion barriers in the root. Different classes of molecules contribute to the formation of extracellular diffusion barriers in an organ- and tissue-specific manner. Cutin and wax are the major components of the cuticle, lignin forms the early Casparian strip, and suberin is deposited in the stage II endodermis and the periderm. The current status of our understanding of the relationships between the chemical structure, ultrastructure and physiological functions of plant diffusion barriers is discussed. Specific aspects of the synthesis of diffusion barrier components and protocols that can be used for the assessment of barrier function and important barrier properties are also presented. PMID:24465172

  10. Tunnel barrier and noncollinear magnetization effects on shot noise in ferromagnetic/semiconductor/ferromagnetic heterojunctions

    International Nuclear Information System (INIS)

    An Xingtao; Liu Jianjun

    2008-01-01

    Based on the scattering approach, we investigate transport properties of electrons in a one-dimensional waveguide that contains a ferromagnetic/semiconductor/ferromagnetic heterojunction and tunnel barriers in the presence of Rashba and Dresselhaus spin-orbit interactions. We simultaneously consider significant quantum size effects, quantum coherence, Rashba and Dresselhaus spin-orbit interactions and noncollinear magnetizations. It is found that the tunnel barrier plays a decisive role in the transmission coefficient and shot noise of the ballistic spin electron transport through the heterojunction. When the small tunnel barriers are considered, the transport properties of electrons are quite different from those without tunnel barriers

  11. Building-transmission factors

    International Nuclear Information System (INIS)

    Woolson, W.A.; Marcum, J.; Scott, W.H.; Staggs, V.E.

    1982-01-01

    Parametric representations (called the nine-parameter formula) of the measurements of the radiation transmission through Japanese house models at the BREN reactor and 60 Co experiments are used to correct the free-in-air (FIA) T65 dose values for buildings shielding in the built-up residential areas at Hiroshima and Nagasaki. The accuracy of transmission factors derived from the nine-parameter formula impact the accuracy of the final-exposure dose estimates in the same manner as the accuracy of weapon yield and FIA radiation transport. A preliminary investigation of the accuracy of these transmission factors, sponsored by the Defense Nuclear Agency, has focused primarily on the adequacy of the Bare Reactor Experiment, Nevada (BREN) radiation environments for producing transmission factor data relevant to the situations at Hiroshima and Nagasaki. In addition, the radiation equivalency of house models used at BREN to Japanese house models and the physical basis for the nine-parameter formula have been studied. This investigation has concluded that the average gamma-ray transmission factors based on the nine-parameter formula are probably too high by about a factor of 2. The large discrepancy between the nine-parameter formula and recent estimates results from the apparent failure to properly account for the large gamma-ray dose component caused by capture gamma rays produced in the house walls by the large neutron flux present at BREN

  12. The "Battle" of Managing Language Barriers in Health Care.

    Science.gov (United States)

    Steinberg, Emma M; Valenzuela-Araujo, Doris; Zickafoose, Joseph S; Kieffer, Edith; DeCamp, Lisa Ross

    2016-12-01

    Providing safe and high-quality health care for children whose parents have limited English proficiency (LEP) remains challenging. Reports of parent perspectives on navigating language discordance in health care are limited. We analyzed portions of 48 interviews focused on language barriers from 2 qualitative interview studies of the pediatric health care experiences of LEP Latina mothers in 2 urban US cities. We found mothers experienced frustration with health care and reported suboptimal accommodation for language barriers. Six themes emerged relevant to health care across settings: the "battle" of managing language barriers, preference for bilingual providers, negative bias toward interpreted encounters, "getting by" with limited language skills, fear of being a burden, and stigma and discrimination experienced by LEP families. Parents' insights highlight reasons why effective language accommodation in health care remains challenging. Partnering with families to address the management of language barriers is needed to improve health care quality and safety for LEP patients and families.

  13. New Barrier Coating Materials for PV Module Backsheets: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Barber, G. D.; Jorgensen, G. J.; Terwilliger, K.; Glick, S. H.; Pern, J.; McMahon, T. J.

    2002-05-01

    This conference paper describes the high moisture barrier high resistivity coatings on polyethylene terepthalate (PET) have been fabricated and characterized for use in PV module back sheet applications. These thin film barriers exhibit water vapor transmission rates (WVTR) as low as 0.1 g/m2-day at 37.8 C and have shown excellent adhesion (> 10 N/mm) to both ethylene vinyl acetate (EVA) and PET even after filtered xenon arc lamp UV exposure. The WVTR and adhesion values for this construction are compared to and shown to be superior to candidate polymeric backsheet materials.

  14. Performance of engineered barriers

    International Nuclear Information System (INIS)

    Rajaram, V.; Dean, P.V.; McLellan, S.A.

    1997-01-01

    Engineered barriers, both vertical and horizontal, have been used to isolate hazardous wastes from contact, precipitation, surface water and groundwater. The primary objective of this study was to determine the performance of subsurface barriers installed throughout the U.S. over the past 20 years to contain hazardous wastes. Evaluation of Resource Conservation and Recovery Act (RCRA) Subtitle C or equivalent caps was a secondary objective. A nationwide search was launched to select hazardous waste sites at which vertical barrier walls and/or caps had been used as the containment method. None of the sites selected had an engineered floor. From an initial list of 130 sites, 34 sites were selected on the basis of availability of monitoring data for detailed analysis of actual field performance. This paper will briefly discuss preliminary findings regarding the design, construction quality assurance/construction quality control (CQA/CQC), and monitoring at the 34 sites. In addition, the short-term performance of these sites (less than 5 years) is presented since very little long-term performance data was available

  15. Small passenger car transmission test: Mercury Lynx ATX transmission

    Science.gov (United States)

    Bujold, M. P.

    1981-01-01

    The testing of a Mercury Lynx automatic transmission is reported. The transmission was tested in accordance with a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these conditions, the transmission attained maximum efficiencies in the mid-ninety percent range both for drive performance test and coast performance tests. The torque, speed, and efficiency curves are presented, which provide the complete performance characteristics for the Mercury Lynx automatic transmission.

  16. Aerosol Transmission of Filoviruses

    Directory of Open Access Journals (Sweden)

    Berhanu Mekibib

    2016-05-01

    Full Text Available Filoviruses have become a worldwide public health concern because of their potential for introductions into non-endemic countries through international travel and the international transport of infected animals or animal products. Since it was first identified in 1976, in the Democratic Republic of Congo (formerly Zaire and Sudan, the 2013–2015 western African Ebola virus disease (EVD outbreak is the largest, both by number of cases and geographical extension, and deadliest, recorded so far in medical history. The source of ebolaviruses for human index case(s in most outbreaks is presumptively associated with handling of bush meat or contact with fruit bats. Transmission among humans occurs easily when a person comes in contact with contaminated body fluids of patients, but our understanding of other transmission routes is still fragmentary. This review deals with the controversial issue of aerosol transmission of filoviruses.

  17. Poverty and price transmission

    DEFF Research Database (Denmark)

    Elleby, Christian

    A key parameter determining the welfare impact from a world market shock is the transmission elasticity which measures the average domestic response to an international price change. Many studies have estimated price transmission elasticities for a large number of countries but the variation...... in these estimates is so far largely unexplored. This paper proposes a model which explains a country's domestic price response to world market shocks in terms of its demand structure. The model delivers two testable predictions; price transmission is increasing in per capita food expenditure and in income...... inequality. The empirical analysis of price changes during the food crises confirms these predictions with a caveat. I find significant inverse U-shaped relationships between domestic food price growth in 2007-8 and 2010-11 and per capita food expenditure. Unequal countries also experienced higher price...

  18. Aerosol Transmission of Filoviruses.

    Science.gov (United States)

    Mekibib, Berhanu; Ariën, Kevin K

    2016-05-23

    Filoviruses have become a worldwide public health concern because of their potential for introductions into non-endemic countries through international travel and the international transport of infected animals or animal products. Since it was first identified in 1976, in the Democratic Republic of Congo (formerly Zaire) and Sudan, the 2013-2015 western African Ebola virus disease (EVD) outbreak is the largest, both by number of cases and geographical extension, and deadliest, recorded so far in medical history. The source of ebolaviruses for human index case(s) in most outbreaks is presumptively associated with handling of bush meat or contact with fruit bats. Transmission among humans occurs easily when a person comes in contact with contaminated body fluids of patients, but our understanding of other transmission routes is still fragmentary. This review deals with the controversial issue of aerosol transmission of filoviruses.

  19. Probabilistic transmission system planning

    CERN Document Server

    Li, Wenyuan

    2011-01-01

    "The book is composed of 12 chapters and three appendices, and can be divided into four parts. The first part includes Chapters 2 to 7, which discuss the concepts, models, methods and data in probabilistic transmission planning. The second part, Chapters 8 to 11, addresses four essential issues in probabilistic transmission planning applications using actual utility systems as examples. Chapter 12, as the third part, focuses on a special issue, i.e. how to deal with uncertainty of data in probabilistic transmission planning. The fourth part consists of three appendices, which provide the basic knowledge in mathematics for probabilistic planning. Please refer to the attached table of contents which is given in a very detailed manner"--

  20. Transmission positron microscopes

    International Nuclear Information System (INIS)

    Doyama, Masao; Kogure, Yoshiaki; Inoue, Miyoshi; Kurihara, Toshikazu; Yoshiie, Toshimasa; Oshima, Ryuichiro; Matsuya, Miyuki

    2006-01-01

    Immediate and near-future plans for transmission positron microscopes being built at KEK, Tsukuba, Japan, are described. The characteristic feature of this project is remolding a commercial electron microscope to a positron microscope. A point source of electrons kept at a negative high voltage is changed to a point source of positrons kept at a high positive voltage. Positional resolution of transmission microscopes should be theoretically the same as electron microscopes. Positron microscopes utilizing trapping of positrons have always positional ambiguity due to the diffusion of positrons

  1. Transmission grid security

    CERN Document Server

    Haarla, Liisa; Hirvonen, Ritva; Labeau, Pierre-Etienne

    2011-01-01

    In response to the growing importance of power system security and reliability, ""Transmission Grid Security"" proposes a systematic and probabilistic approach for transmission grid security analysis. The analysis presented uses probabilistic safety assessment (PSA) and takes into account the power system dynamics after severe faults. In the method shown in this book the power system states (stable, not stable, system breakdown, etc.) are connected with the substation reliability model. In this way it is possible to: estimate the system-wide consequences of grid faults; identify a chain of eve

  2. Markers for blood-brain barrier integrity

    DEFF Research Database (Denmark)

    Saunders, Norman R; Dziegielewska, Katarzyna M; Møllgård, Kjeld

    2015-01-01

    In recent years there has been a resurgence of interest in brain barriers and various roles their intrinsic mechanisms may play in neurological disorders. Such studies require suitable models and markers to demonstrate integrity and functional changes at the interfaces between blood, brain...... known when first introduced, but seem to have been forgotten since. Understanding these limitations is important because Evans blue is still the most commonly used marker of brain barrier integrity and those using it seem oblivious to problems arising from its in vivo application. The introduction...... of HRP in the mid twentieth-century was an important advance because its reaction product can be visualized at the electron microscopical level, but it also has limitations. Advantages and disadvantages of these markers will be discussed together with a critical evaluation of alternative approaches...

  3. Development of small and medium enterprises to export to external barriers

    OpenAIRE

    Saeed Ranjbar; Ebrahim Abbasi

    2014-01-01

    The aim of this study is to explore the current exportchallenges for SMEs in Pakistan and how these barriers affect the SMEs. Oneindustry (textile) was selected for this study. Findings of this study showedthat internal barriers are more influential than external barriers. This studyis limited to one industry . This study disseminates the attention of SMEsexport managers towards the genuine and main problems coming across the SMEexports so they can deal with these barriers to magnify their ex...

  4. Lifetime Modeling of Thermal Barrier Coatings

    OpenAIRE

    Hille, T.S.

    2009-01-01

    Thermal barrier coatings (TBCs) are applied in gas turbines to enhance their thermal efficiency by isolating the metallic components from the aggressive hot gas. TBC lifetime is limited by damage processes originating at internal interfaces, which may ultimately lead to delamination and spallation. In the present thesis constitutive models are presented for the coating components and the most detrimental failure mechanisms. To simulate the thermomechanical failure response, the numerical mode...

  5. Wave transmission at low-crested structures using neural networks

    NARCIS (Netherlands)

    Van Oosten, R.P.; Peixó Marco, J.; Van der Meer, J.W.; Van Gent, M.; Verhagen, H.J.

    2006-01-01

    The European Union funded project DELOS was focused on wave transmission and an extensive database on low-crested rubble mound structures was generated. During DELOS, new empirical wave transmission formulae were derived. These formulae still showed a considerable scatter due to a limited number of

  6. Protocol for measuring light transmission of horticultural screens

    NARCIS (Netherlands)

    Swinkels, G.L.A.M.; Hemming, S.; Mohammadkhani, V.; Ruijven, van J.P.M.

    2013-01-01

    The light transmission is an important property for horticultural screens. For energy screens in particular, an accurate measurement of the light transmission is important because these screens are often used during the day, in the winter period when radiation is limited. For shading screens the

  7. Centralized Coordination of Load Shedding & Protection System of Transmission Lines

    DEFF Research Database (Denmark)

    Hoseinzadeh, Bakhtyar; Bak, Claus Leth

    2018-01-01

    The power system integrity is vulnerable to thermal limit of transmission lines due to overloading and consequently activation of their protection devices following severe contingencies. In this paper, the loading rate of transmission lines is monitored online and is considered in the centralized......, over current protection....

  8. Effect of a gap opening on the conductance of graphene with magnetic barrier structures

    Science.gov (United States)

    Esmailpour, Mohammad

    2018-04-01

    In the present study Klein tunneling in a single-layer gapped graphene was investigated by transfer matrix method under normal magnetic field for one and two magnetic barriers. Calculations show that electron transmission through a magnetic barrier is deflected to positive angles and reduces as the magnitude of magnetic field and especially the energy gap increases. This reduction is even more significant in larger fields so that after reaching a specific value of energy gap, an effective confinement for fermions and suppression of Klein tunneling is reached particularly in normal incidence and the conductance becomes zero. Unlike one barrier, the process of tunneling through two magnetic barriers induces symmetric transmission probability versus the incident angle; even, for lower energy gaps, electron transmission probability increases which in turn reduces total conductance via proper changes in the value of the magnetic field and energy gap. In general, it is concluded that confining electrons in asymmetric transmission through one barrier is conducted better than two barriers.

  9. "Recognizing rapport": health professionals' lived experience of caring for patients under transmission-based precautions in an Australian health care setting.

    Science.gov (United States)

    Godsell, Mary-Rose; Shaban, Ramon Z; Gamble, Jenny

    2013-11-01

    Preventing health care-associated infections is essential to the safety and quality of health care. Although patients' experience of care under isolation is well established, little is known of health care workers' experiences when providing such care. This study explored the health professionals; lived experience of caring for patients under transmission-based precautions. Interpretive phenomenology was used to examine 12 health care professionals' lived experience of providing care under transmission-based precautions in 3 health care facilities in Australia. Data were obtained from in-depth interviews and observations of health professionals. The essential phenomena of "recognizing rapport" represented the health professionals' lived experience. Three themes emerged starting with (1) relationships with others, their rapport and communication with patients, patients' families and visitors, and colleagues. These relationships are influenced by (2) barriers to practice, such as personal level of comfort when wearing personal protective equipment, physical limitations of the environment, and management of workload and resources. Such barriers influence (3) patient outcomes, namely the quality of the care provided and adverse events. In the context of caring for patients under transmission-based precautions, the relationships between health professionals and their patients are critical to the quality and safety of health care with respect to infection prevention and control. Copyright © 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

  10. Intergenerational Transmission of Volunteering

    NARCIS (Netherlands)

    Bekkers, René

    2007-01-01

    In this article, I investigate the strength of intergenerational transmission of volunteering for non-profit associations in The Netherlands. Data from the Family Survey of the Dutch Population 2000 reveal that there are significant relations between current volunteering and parental volunteering in

  11. Scanning transmission electron microscope

    NARCIS (Netherlands)

    Kruit, P.

    2006-01-01

    The invention relates to a scanning transmission electron microscope comprising an electron source, an electron accelerator and deflection means for directing electrons emitted by the electron source at an object to be examined, and in addition a detector for detecting electrons coming from the

  12. Drivers of Tuberculosis Transmission

    NARCIS (Netherlands)

    Mathema, Barun; Andrews, Jason R.; Cohen, Ted; Borgdorff, Martien W.; Behr, Marcel; Glynn, Judith R.; Rustomjee, Roxana; Silk, Benjamin J.; Wood, Robin

    2017-01-01

    Measuring tuberculosis transmission is exceedingly difficult, given the remarkable variability in the timing of clinical disease after Mycobacterium tuberculosis infection; incident disease can result from either a recent (ie, weeks to months) or a remote (ie, several years to decades) infection

  13. 4. CRIMINALISING HIV TRANSMISSION

    African Journals Online (AJOL)

    Esem

    Method: A comprehensive analysis of both global and. Zambianpublications, legislation and case laws was conducted. Results: Proponents of criminalisation of HIV transmission argue that criminalization would serve as a deterrent to the culprit and others to engage in prohibited conduct in future while the opponents argue ...

  14. Barrier mechanisms in the Drosophila blood-brain barrier

    Directory of Open Access Journals (Sweden)

    Samantha Jane Hindle

    2014-12-01

    Full Text Available The invertebrate blood-brain barrier field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through GPCR signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate blood-brain barrier has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many blood-brain barrier mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the blood-brain barrier can govern whole animal physiologies. This includes novel functions of blood-brain barrier gap junctions in orchestrating synchronized neuroblast proliferation, and of blood-brain barrier secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate blood-brain barrier anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.

  15. [Barrier methods of contraception].

    Science.gov (United States)

    Goldsmith, A; Edelman, D A

    1982-01-01

    Vaginal methods of contraception were the earliest types used and some references to them date back to antiquity. Most of the vaginal contraceptive agents identified by the ancient Greeks, Indians, Japanese, and Chinese have been found in modern laboratory tests to have spermicidal properties, but it is doubtful that the methods were fully reliable or were used by many people. During the 19th century the condom, vaginal spermicides, and diaphragm became available. The development of nonoxynol-9 and other nonirritating but effective spermicidal agents improved vaginal contraceptives greatly by the 1950s, but starting in the 1960s newer methods began to replace the vaginal methods. Interest in barrier methods has been reawakened somewhat by concern about the health effects of hormonal methods. At present all barrier methods leave something to be desired. Failure rates of 3-30% for barrier methods in general have been estimated, but the higher rates are believed due to incorrect or inconsistent use. Theoretical failure rates of condoms and diaphragms have been estimated at 3/100 women-years, but in actual use failure rates may reach 15 for condoms and 13 for diaphragms used with spermicides. Use-effectiveness rates are greatly influenced by motivation. For a variety of reasons, the acceptability of barrier methods is low, especially in developing countries. New developments in spermicidal agents include sperm inhibitors, which impede the fertilizing capacity of sperm rather than attempting a spermicidal effect; a number of such agents have been studied and have proven more effective in animal tests than conventional spermicides. Neosampoon, a new spermicidal foam, has attracted an increasing number of users, especially in developing countries. A new condom, made of thin polymers and containing a standard dose of nonoxynol-9, has been designed to dissolve in the vaginal fluid. Further studies are needed of its acceptability, efficacy, and side effects before it becomes

  16. Support or Barrier?

    DEFF Research Database (Denmark)

    Sanden, Guro Refsum; Lønsmann, Dorte

    employees use to cross language boundaries in their everyday work, and, secondly, how these practices relate to top-down language management in the case companies. Our findings show that employees are often dependent on ad hoc and informal solutions in cross- language situations, which leads us......This study offers a critical look at how corporate-level language management influences front-line language practices among employees in three multinational corporations (MNCs) headquartered in Scandinavia. Based on interview and document data, we examine, firstly, what front-line practices...... to a discussion of how a company’s language policy may be seen as both support and a barrier....

  17. Assessing access barriers to tuberculosis care with the tool to Estimate Patients' Costs: pilot results from two districts in Kenya

    NARCIS (Netherlands)

    Mauch, V.; Woods, N.; Kirubi, B.; Kipruto, H.; Sitienei, J.; Klinkenberg, E.

    2011-01-01

    Background: The poor face geographical, socio-cultural and health system barriers in accessing tuberculosis care. These may cause delays to timely diagnosis and treatment resulting in more advanced disease and continued transmission of TB. By addressing barriers and reasons for delay, costs incurred

  18. Assessing access barriers to tuberculosis care with the tool to Estimate Patients' Costs: pilot results from two districts in Kenya

    NARCIS (Netherlands)

    Mauch, Verena; Woods, Naomi; Kirubi, Beatrice; Kipruto, Hillary; Sitienei, Joseph; Klinkenberg, Eveline

    2011-01-01

    The poor face geographical, socio-cultural and health system barriers in accessing tuberculosis care. These may cause delays to timely diagnosis and treatment resulting in more advanced disease and continued transmission of TB. By addressing barriers and reasons for delay, costs incurred by TB

  19. Suburban Poverty: Barriers to Services and Injury Prevention among Marginalized Women Who Use Methamphetamine

    Directory of Open Access Journals (Sweden)

    Boeri, Miriam

    2011-07-01

    Full Text Available Objective: This paper aims to identify the needed healthcare and social services barriers for women living in suburban communities who are using or have used methamphetamine. Drug users are vulnerable to injury, violence and transmission of infectious diseases, and having access to healthcare has been shown to positively influence prevention and intervention among this population. Yet little is known regarding the social context of suburban drug users, their risks behaviors, and their access to healthcare.Methods: The data collection involved participant observation in the field, face-to-face interviews and focus groups. Audio-recorded in-depth life histories, drug use histories, and resource needs were collected from 31 suburban women who were former or current users of methamphetamine. The majority was drawn from marginalized communities and highly vulnerable to risk for injury and violence. We provided these women with healthcare and social service information and conducted follow-up interviews to identify barriers to these services.Results: Barriers included (1 restrictions imposed by the services and (2 limitations inherent in the women’s social, economic, or legal situations. We found that the barriers increased the women’s risk for further injury, violence and transmission of infectious diseases. Women who could not access needed healthcare and social resources typically used street drugs that were accessible and affordable to self-medicate their untreated emotional and physical pain.Conclusion: Our findings add to the literatureon how healthcare and social services are related to injury prevention. Social service providers in the suburbs were often indifferent to the needs of drug-using women. For these women, health services were accessed primarily at emergency departments (ED. To break the cycle of continued drug use, violence and injury, we suggest that ED staff be trained to perform substance abuse assessments and provide

  20. Breaking Barriers in Polymer Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Love, Lonnie J [ORNL; Duty, Chad E [ORNL; Post, Brian K [ORNL; Lind, Randall F [ORNL; Lloyd, Peter D [ORNL; Kunc, Vlastimil [ORNL; Peter, William H [ORNL; Blue, Craig A [ORNL

    2015-01-01

    Additive Manufacturing (AM) enables the creation of complex structures directly from a computer-aided design (CAD). There are limitations that prevent the technology from realizing its full potential. AM has been criticized for being slow and expensive with limited build size. Oak Ridge National Laboratory (ORNL) has developed a large scale AM system that improves upon each of these areas by more than an order of magnitude. The Big Area Additive Manufacturing (BAAM) system directly converts low cost pellets into a large, three-dimensional part at a rate exceeding 25 kg/h. By breaking these traditional barriers, it is possible for polymer AM to penetrate new manufacturing markets.

  1. Velocity barrier-controlled of spin-valley polarized transport in monolayer WSe2 junction

    Science.gov (United States)

    Qiu, Xuejun; Lv, Qiang; Cao, Zhenzhou

    2018-05-01

    In this work, we have theoretically investigated the influence of velocity barrier on the spin-valley polarized transport in monolayer (ML) WSe2 junction with a large spin-orbit coupling (SOC). Both the spin-valley resolved transmission probabilities and conductance are strong dependent on the velocity barrier, as the velocity barrier decreases to 0.06, a spin-valley polarization of exceeding 90% is observed, which is distinct from the ML MoS2 owing to incommensurable SOC. In addition, the spin-valley polarization is further increased above 95% in a ML WSe2 superlattice, in particular, it's found many extraordinary velocity barrier-dependent transport gaps for multiple barrier due to evanescent tunneling. Our results may open an avenue for the velocity barrier-controlled high-efficiency spin and valley polarizations in ML WSe2-based electronic devices.

  2. Age Limits

    OpenAIRE

    Jan Antfolk

    2017-01-01

    Whereas women of all ages prefer slightly older sexual partners, men—regardless of their age—have a preference for women in their 20s. Earlier research has suggested that this difference between the sexes’ age preferences is resolved according to women’s preferences. This research has not, however, sufficiently considered that the age range of considered partners might change over the life span. Here we investigated the age limits (youngest and oldest) of considered and actual sex partners in...

  3. Transmission Electron Microscopy Physics of Image Formation

    CERN Document Server

    Kohl, Helmut

    2008-01-01

    Transmission Electron Microscopy: Physics of Image Formation presents the theory of image and contrast formation, and the analytical modes in transmission electron microscopy. The principles of particle and wave optics of electrons are described. Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast. Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal-structure analysis and imaging of lattices and their defects. X-ray microanalysis and electron energy-loss spectroscopy are treated as analytical methods. Specimen damage and contamination by electron irradiation limits the resolution for biological and some inorganic specimens. This fifth edition includes discussion of recent progress, especially in the area of aberration correction and energy filtering; moreover, the topics introduced in the fourth edition have been updated. Transmission Electron Microscopy: Physics of Image Formation is written f...

  4. There are many barriers to species' migrations

    Directory of Open Access Journals (Sweden)

    Kenneth J Feeley

    2014-06-01

    Full Text Available Temperature-change trajectories are being used to identify the geographic barriers and thermal ‘cul-de-sacs’ that will limit the ability of many species to track climate change by migrating. We argue that there are many other potential barriers to species’ migrations. These include stable ecotones, discordant shifts in climatic variables, human land use, and species’ limited dispersal abilities. To illustrate our argument, for each 0.5° latitude/longitude grid cell of the Earth’s land surface, we mapped and tallied the number of cells for which future (2060–2080 climate represents an analog of the focal cell’s current climate. We compared results when only considering temperature with those for which both temperature and total annual precipitation were considered in concert. We also compared results when accounting for only geographic barriers (no cross-continental migration with those involving both geographic and potential ecological barriers (no cross-biome migration. As expected, the number of future climate analogs available to each pixel decreased markedly with each added layer of complexity (e.g. the proportion of the Earth’s land surface without any available future climate analogs increased from 3% to more than 36% with the inclusion of precipitation and ecological boundaries. While including additional variables can increase model complexity and uncertainty, we must strive to incorporate the factors that we know will limit species’ ranges and migrations if we hope to predict the effects of climate change at a high-enough degree of accuracy to guide management decisions.

  5. Paving the way to nanoionics: atomic origin of barriers for ionic transport through interfaces

    Science.gov (United States)

    Frechero, M. A.; Rocci, M.; Sánchez-Santolino, G.; Kumar, Amit; Salafranca, J.; Schmidt, Rainer; Díaz-Guillén, M. R.; Durá, O. J.; Rivera-Calzada, A.; Mishra, R.; Jesse, Stephen; Pantelides, S. T.; Kalinin, Sergei V.; Varela, M.; Pennycook, S. J.; Santamaria, J.; Leon, C.

    2015-12-01

    The blocking of ion transport at interfaces strongly limits the performance of electrochemical nanodevices for energy applications. The barrier is believed to arise from space-charge regions generated by mobile ions by analogy to semiconductor junctions. Here we show that something different is at play by studying ion transport in a bicrystal of yttria (9% mol) stabilized zirconia (YSZ), an emblematic oxide ion conductor. Aberration-corrected scanning transmission electron microscopy (STEM) provides structure and composition at atomic resolution, with the sensitivity to directly reveal the oxygen ion profile. We find that Y segregates to the grain boundary at Zr sites, together with a depletion of oxygen that is confined to a small length scale of around 0.5 nm. Contrary to the main thesis of the space-charge model, there exists no evidence of a long-range O vacancy depletion layer. Combining ion transport measurements across a single grain boundary by nanoscale electrochemical strain microscopy (ESM), broadband dielectric spectroscopy measurements, and density functional calculations, we show that grain-boundary-induced electronic states act as acceptors, resulting in a negatively charged core. Besides the possible effect of the modified chemical bonding, this negative charge gives rise to an additional barrier for ion transport at the grain boundary.

  6. Regional transmission subsystem planning

    Energy Technology Data Exchange (ETDEWEB)

    Costa Bortoni, Edson da [Quadrante Softwares Especializados Ltda., Itajuba, MG (Brazil); Bajay, Sergio Valdir; Barros Correia, Paulo de [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica; Santos, Afonso Henriques Moreira; Haddad, Jamil [Escola Federal de Engenharia de Itajuba, MG (Brazil)

    1994-12-31

    This work presents an approach for the planning of transmission systems by employing mixed--integer linear programming to obtain a cost and operating characteristics optimized system. The voltage loop equations are written in a modified form, so that, at the end of the analysis, the model behaves as a DC power flow, with the help of the two Kirchhoff`s laws, exempting the need of interaction with an external power flow program for analysis of the line loading. The model considers the occurrence of contingencies, so that the final result is a network robust to the most severe contingencies. This whole technique is adapted to the regional electric power transmission subsystems. (author) 9 refs., 4 figs.

  7. Mechanisms, Transmissions and Applications

    CERN Document Server

    Corves, Burkhard

    2012-01-01

    The first Workshop on Mechanisms, Transmissions and Applications -- MeTrApp-2011 was organized by the Mechatronics Department at the Mechanical Engineering Faculty, “Politehnica” University of Timisoara, Romania, under the patronage of the IFToMM Technical Committees Linkages and Mechanical Controls and Micromachines. The workshop brought together researchers and students who work in disciplines associated with mechanisms science and offered a great opportunity for scientists from all over the world to present their achievements, exchange innovative ideas and create solid international links, setting the trend for future developments in this important and creative field. The topics treated in this volume are mechanisms and machine design, mechanical transmissions, mechatronic and biomechanic applications, computational and experimental methods, history of mechanism and machine science and teaching methods.

  8. Power flow studies in HVAC and HVDC transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Oyedokun, D.T.; Folly, K.A. [Cape Town Univ. (South Africa). Dept. of Electrical Engineering

    2008-07-01

    Flexible AC transmission system (FACTS) devices, additional high voltage AC (HVAC) lines, and additional HVDC transmission lines can all be used to increase the capacity of transmission infrastructure. In this paper, 3 case studies were presented to evaluate the different technologies. Power flow analyses were conducted in order to determine the most feasible method of increasing capacity. A 35 per cent increase in load demand was considered in relation to changes in power flow, rotor angle, loading, and reactive power compensation. The study showed that DC limits were reduced at the rectifier substation, and more power was routed via the HVAC line while less power was routed via the HVDC line. A comparison of the case studies showed that using an HVAC transmission line in parallel with an additional HVAC line was the most suitable method of increasing transmission infrastructure. Transmission losses for the double circuit HVAC lines were approximately 60 MW. 13 refs., 6 tabs., 6 figs.

  9. Small passenger car transmission test; Chevrolet LUV transmission

    Science.gov (United States)

    Bujold, M. P.

    1980-01-01

    A 1978 Chevrolet LUV manual transmission tested per the applicable portions of a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these test conditions, the transmission attained maximum efficiencies in the upper ninety percent range for both drive performance tests and coast performance tests. The major results of this test (torque, speed, and efficiency curves) are presented. Graphs map the complete performance characteristics for the Chevrolet LUV transmission.

  10. Available transmission capacity assessment

    Directory of Open Access Journals (Sweden)

    Škokljev Ivan

    2012-01-01

    Full Text Available Effective power system operation requires the analysis of vast amounts of information. Power market activities expose power transmission networks to high-level power transactions that threaten normal, secure operation of the power system. When there are service requests for a specific sink/source pair in a transmission system, the transmission system operator (TSO must allocate the available transfer capacity (ATC. It is common that ATC has a single numerical value. Additionally, the ATC must be calculated for the base case configuration of the system, while generation dispatch and topology remain unchanged during the calculation. Posting ATC on the internet should benefit prospective users by aiding them in formulating their requests. However, a single numerical value of ATC offers little for prospect for analysis, planning, what-if combinations, etc. A symbolic approach to the power flow problem (DC power flow and ATC offers a numerical computation at the very end, whilst the calculation beforehand is performed by using symbols for the general topology of the electrical network. Qualitative analysis of the ATC using only qualitative values, such as increase, decrease or no change, offers some new insights into ATC evaluation, multiple transactions evaluation, value of counter-flows and their impact etc. Symbolic analysis in this paper is performed after the execution of the linear, symbolic DC power flow. As control variables, the mathematical model comprises linear security constraints, ATC, PTDFs and transactions. The aim is to perform an ATC sensitivity study on a five nodes/seven lines transmission network, used for zonal market activities tests. A relatively complicated environment with twenty possible bilateral transactions is observed.

  11. Operational electricity transmission rates

    International Nuclear Information System (INIS)

    Roggen, M.

    1997-01-01

    In a liberalized electricity market both the consumers and the producers of electricity must pay for the use of the power transmission network. Thus, the net manager has unlimited options to realize efficiency improvements. A neutral and transparent management of the power grid is necessary to avoid disturbance of the market. KEMA Consulting translated abstract ideas and strategic advices to operational concepts in its report 'A framework for the determination of tariffs of the transport in the Dutch electricity sector'

  12. Fluorescence microscopy with diffraction resolution barrier broken by stimulated emission

    OpenAIRE

    Klar, Thomas A.; Jakobs, Stefan; Dyba, Marcus; Egner, Alexander; Hell, Stefan W.

    2000-01-01

    The diffraction barrier responsible for a finite focal spot size and limited resolution in far-field fluorescence microscopy has been fundamentally broken. This is accomplished by quenching excited organic molecules at the rim of the focal spot through stimulated emission. Along the optic axis, the spot size was reduced by up to 6 times beyond the diffraction barrier. The simultaneous 2-fold improvement in the radial direction rendered a nearly spherical fluorescence spot with a diameter of 9...

  13. Schottky barriers at metal-finite semiconducting carbon nanotube interfaces

    OpenAIRE

    Xue, Yongqiang; Ratner, Mark A.

    2003-01-01

    Electronic properties of metal-finite semiconducting carbon nanotube interfaces are studied as a function of the nanotube length using a self-consistent tight-binding theory. We find that the shape of the potential barrier depends on the long-range tail of the charge transfer, leading to an injection barrier thickness comparable to half of the nanotube length until the nanotube reaches the bulk limit. The conductance of the nanotube junction shows a transition from tunneling to thermally-acti...

  14. Aluminum oxide barrier coating on polyethersulfone substrate by atomic layer deposition for barrier property enhancement

    International Nuclear Information System (INIS)

    Kim, Hyun Gi; Kim, Sung Soo

    2011-01-01

    Aluminum oxide layers were deposited on flexible polyethersulfone (PES) substrates via plasma enhanced atomic layer deposition (PEALD) process using trimethylaluminum (TMA) and oxygen as precursor and reactant materials. Several process parameters in PEALD process were investigated in terms of refractive index and layer thickness. Number of process cycle increased the thickness and refractive index of the layer to enhance the barrier properties. Non-physisorbed TMA and unreacted oxygen were purged before and after the plasma reaction, respectively. Identical purge time was applied to TMA and oxygen and it was optimized for 10 s. Thinner and denser layer was formed as substrate temperature increased. However, the PES substrate could be deformed above 120 o C. Aluminum oxide layer formed on PES at optimized conditions have 11.8 nm of thickness and reduced water vapor transmission rate and oxygen transmission rate to below 4 x 10 -3 g/m 2 day and 4 x 10 -3 cm 3 /m 2 day, respectively. Polycarbonate and polyethylene naphthalate films were also tested at optimized conditions, and they also showed quite appreciable barrier properties to be used as plastic substrates.

  15. Frequent transmission of immunodeficiency viruses among bobcats and pumas

    Science.gov (United States)

    Franklin, S.P.; Troyer, J.L.; TerWee, J.A.; Lyren, L.M.; Boyce, W.M.; Riley, S.P.D.; Roelke, M.E.; Crooks, K.R.; VandeWoude, S.

    2007-01-01

    With the exception of human immunodeficiency virus (HIV), which emerged in humans after cross-species transmissions of simian immunodeficiency viruses from nonhuman primates, immunodeficiency viruses of the family Lentiviridae represent species-specific viruses that rarely cross species barriers to infect new hosts. Among the Felidae, numerous immunodeficiency-like lentiviruses have been documented, but only a few cross-species transmissions have been recorded, and these have not been perpetuated in the recipient species. Lentivirus seroprevalence was determined for 79 bobcats (Lynx rufus) and 31 pumas (Puma concolor) from well-defined populations in Southern California. Partial genomic sequences were subsequently obtained from 18 and 12 seropositive bobcats and pumas, respectively. Genotypes were analyzed for phylogenic relatedness and genotypic composition among the study set and archived feline lentivirus sequences. This investigation of feline immunodeficiency virus infection in bobcats and pumas of Southern California provides evidence that cross-species infection has occurred frequently among these animals. The data suggest that transmission has occurred in multiple locations and are most consistent with the spread of the virus from bobcats to pumas. Although the ultimate causes remain unknown, these transmission events may occur as a result of puma predation on bobcats, a situation similar to that which fostered transmission of HIV to humans, and likely represent the emergence of a lentivirus with relaxed barriers to cross-species transmission. This unusual observation provides a valuable opportunity to evaluate the ecological, behavioral, and molecular conditions that favor repeated transmissions and persistence of lentivirus between species. Copyright ?? 2007, American Society for Microbiology. All Rights Reserved.

  16. Performing a local barrier operation

    Science.gov (United States)

    Archer, Charles J; Blocksome, Michael A; Ratterman, Joseph D; Smith, Brian E

    2014-03-04

    Performing a local barrier operation with parallel tasks executing on a compute node including, for each task: retrieving a present value of a counter; calculating, in dependence upon the present value of the counter and a total number of tasks performing the local barrier operation, a base value, the base value representing the counter's value prior to any task joining the local barrier; calculating, in dependence upon the base value and the total number of tasks performing the local barrier operation, a target value of the counter, the target value representing the counter's value when all tasks have joined the local barrier; joining the local barrier, including atomically incrementing the value of the counter; and repetitively, until the present value of the counter is no less than the target value of the counter: retrieving the present value of the counter and determining whether the present value equals the target value.

  17. Directional gear ratio transmissions

    Science.gov (United States)

    Lafever, A. E. (Inventor)

    1984-01-01

    Epicyclic gear transmissions which transmit output at a gear ratio dependent only upon the input's direction are considered. A transmission housing envelops two epicyclic gear assemblies, and has shafts extending from it. One shaft is attached to a sun gear within the first epicyclic gear assembly. Planet gears are held symmetrically about the sun gear by a planet gear carrier and are in mesh with both the sun gear and a ring gear. Two unidirectional clutches restrict rotation of the first planet gear carrier and ring gear to one direction. A connecting shaft drives a second sun gear at the same speed and direction as the first planet gear carrier while a connecting portion drives a second planet gear carrier at the same speed and direction as the first ring gear. The transmission's output is then transmitted by the second ring gear to the second shaft. Input is transmitted at a higher gear ratio and lower speed for all inputs in the first direction than in the opposite direction.

  18. Benefits of transmission interconnections

    International Nuclear Information System (INIS)

    Lyons, D.

    2006-01-01

    The benefits of new power transmission interconnections from Alberta were discussed with reference to the challenges and measures needed to move forward. Alberta's electricity system has had a long period of sustained growth in generation and demand and this trend is expected to continue. However, no new interconnections have been built since 1985 because the transmission network has not expanded in consequence with the growth in demand. As such, Alberta remains weakly interconnected with the rest of the western region. The benefits of stronger transmission interconnections include improved reliability, long-term generation capability, hydrothermal synergies, a more competitive market, system efficiencies and fuel diversity. It was noted that the more difficult challenges are not technical. Rather, the difficult challenges lie in finding an appropriate business model that recognizes different market structures. It was emphasized that additional interconnections are worthwhile and will require significant collaboration among market participants and governments. It was concluded that interties enable resource optimization between systems and their benefits far exceed their costs. tabs., figs

  19. How financial transmission rights curb market power

    Energy Technology Data Exchange (ETDEWEB)

    Stoft, S.

    1997-06-01

    This paper demonstrates that financial transmission rights allow their owners to capture at least a portion, and sometimes all, of the congestion rents. This extends work in this area by Shmuel Oren which was limited to the case in which generators could not purchase financial transmission rights. One form of financial rights, Transmission Congestion Contracts (TCCs), is shown to be so effective in reducing market power that as few as two generators facing a demand curve with zero elasticity may be forced to sell at marginal cost. The extent to which market power is limited depends on the extent to which total generation capacity exceeds export capacity and on the size of individual generators. A relationship is derived that determines when TCCs will eliminate market power. In the case of a three line network, it is shown that the reduction in market power that can be accomplished with {open_quotes}active transmission rights{close_quotes} can also be accomplished with simple contracts for differences.

  20. Antimicrobial peptides in the female reproductive tract: a critical component of the mucosal immune barrier with physiological and clinical implications.

    Science.gov (United States)

    Yarbrough, Victoria L; Winkle, Sean; Herbst-Kralovetz, Melissa M

    2015-01-01

    At the interface of the external environment and the mucosal surface of the female reproductive tract (FRT) lies a first-line defense against pathogen invasion that includes antimicrobial peptides (AMP). Comprised of a unique class of multifunctional, amphipathic molecules, AMP employ a wide range of functions to limit microbial invasion and replication within host cells as well as independently modulate the immune system, dampen inflammation and maintain tissue homeostasis. The role of AMP in barrier defense at the level of the skin and gut has received much attention as of late. Given the far reaching implications for women's health, maternal and fetal morbidity and mortality, and sexually transmissible and polymicrobial diseases, we herein review the distribution and function of key AMP throughout the female reproductive mucosa and assess their role as an essential immunological barrier to microbial invasion throughout the reproductive cycle of a woman's lifetime. A comprehensive search in PubMed/Medline was conducted related to AMP general structure, function, signaling, expression, distribution and barrier function of AMP in the FRT, hormone regulation of AMP, the microbiome of the FRT, and AMP in relation to implantation, pregnancy, fertility, pelvic inflammatory disease, complications of pregnancy and assisted reproductive technology. AMP are amphipathic peptides that target microbes for destruction and have been conserved throughout all living organisms. In the FRT, several major classes of AMP are expressed constitutively and others are inducible at the mucosal epithelium and by immune cells. AMP expression is also under the influence of sex hormones, varying throughout the menstrual cycle, and dependent on the vaginal microbiome. AMP can prevent infection with sexually transmissible and opportunistic pathogens of the female reproductive tissues, although emerging understanding of vaginal dysbiosis suggests induction of a unique AMP profile with increased

  1. Alternative approaches to transmission investment

    International Nuclear Information System (INIS)

    Welch, J.L.

    2004-01-01

    The International Transmission Company (ITC) is an independent power transmission company that owns, operates and maintains the high voltage transmission system in southeastern Michigan. The company's current focus is on investing in the transmission infrastructure to improve reliability, relieve congestion, improve access to generation and reduce energy costs for consumers. There is a need for investment in power transmission. Trends indicate that power transactions are on the rise while transmission investment is lagging because pricing protocols are inadequate and there is no regional tariff mechanism to allocate the benefits of new investment. The presentation reviewed the applicability of FTRs to transmission owners and the pitfalls of participant funding pricing. It also outlined the regional benefit allocation mechanism (RBAM) with an illustrative example. It was concluded that existing pricing policies must be improved to address the growing need for transmission investment. RBAM is needed to help investors recover costs from project beneficiaries. figs

  2. Laser Transmission Through Cirrus Clouds

    National Research Council Canada - National Science Library

    Liou, Kuo-Nam

    2004-01-01

    Laser transmission model development. We developed a number of 2D radiative transfer models based on the successive-order-of-scattering approach for the computation of airborne high-energy laser transmission and backscattering...

  3. Exposure, Uptake, and Barriers

    Science.gov (United States)

    Baeza-Squiban, Armelle; Lanone, Sophie

    The nanotechnologies market is booming, e.g., in the food industry (powder additives, etc.) and in medical applications (drug delivery, prosthetics, diagnostic imaging, etc.), but also in other industrial sectors, such as sports, construction, cosmetics, and so on. In this context, with an exponential increase in the number of current and future applications, it is particularly important to evaluate the problem of unintentional (i.e., non-medical) exposure to manufactured nanoparticles (so excluding nanoparticles found naturally in the environment). In this chapter, we begin by discussing the various parameters that must be taken into account in any serious assessment of exposure to man-made nanoparticles. We then list the potential routes by which nanoparticles might enter into the organism, and outline the mechanisms whereby they could get past the different biological barriers. Finally, we describe the biodistribution of nanoparticles in the organism and the way they are eliminated.

  4. Countermeasures and barriers

    International Nuclear Information System (INIS)

    Petersen, Johannes

    2005-10-01

    In 1973 Haddon proposed ten strategies for reducing and avoiding damages based on a model of potential harmful energy transfer (Haddon, 1973). The strategies apply to a large variety of unwanted phenomena. Haddon's pioneering work on countermeasures has had a major influence on later thinking about safety. Considering its impact it is remarkable that the literature offers almost no discussions related to the theoretical foundations of Haddon's countermeasure strategies. The present report addresses a number of theoretical issues related to Haddon's countermeasure strategies, which are: 1) A reformulation and formalization of Haddon's countermeasure strategies. 2) An identification and description of some of the problems associated with the term 'barrier'. 3) Suggestions for a more precise terminology based on the causal structure of countermeasures. 4) Extending the scope of countermeasures to include sign-based countermeasures. (au)

  5. Countermeasures and barriers

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Johannes [Oersted - DTU, Automation, Kgs. Lyngby (Denmark)

    2005-10-01

    In 1973 Haddon proposed ten strategies for reducing and avoiding damages based on a model of potential harmful energy transfer (Haddon, 1973). The strategies apply to a large variety of unwanted phenomena. Haddon's pioneering work on countermeasures has had a major influence on later thinking about safety. Considering its impact it is remarkable that the literature offers almost no discussions related to the theoretical foundations of Haddon's countermeasure strategies. The present report addresses a number of theoretical issues related to Haddon's countermeasure strategies, which are: 1) A reformulation and formalization of Haddon's countermeasure strategies. 2) An identification and description of some of the problems associated with the term 'barrier'. 3) Suggestions for a more precise terminology based on the causal structure of countermeasures. 4) Extending the scope of countermeasures to include sign-based countermeasures. (au)

  6. Our views on transmission policy

    International Nuclear Information System (INIS)

    Wellford, W.H.; Sutley, N.H.

    1990-01-01

    In this article the authors discuss the need for predictable and fair access to transmission facilities in order to ensure competitive generation of power. They propose that the Federal Energy Regulatory Commission should regulate transmission to prevent a utility from gaining a competitive advantage in electricity generation markets, the incorporation of transmission access into every bidding program under state jurisdiction, and requirement of transmission rates, terms and conditions for all in-state utilities be included in the request for proposal

  7. Thames barrier (flood protection barriers on the Thames)

    International Nuclear Information System (INIS)

    Ilkovic, J.

    2005-01-01

    In this paper the flood protection barriers on the Thames are presented. The flood protection system on the Thames in 1984 was commissioned. During two decades this barrier was used 54 times against to the high water and 34 times against storm-sewage. There is installed buttress type hydroelectric power plant

  8. The Achilles' heel of prevention to mother-to-child transmission of HIV: Protocol implementation, uptake, and sustainability.

    Science.gov (United States)

    Rodriguez, Violeta J; LaCabe, Richard P; Privette, C Kyle; Douglass, K Marie; Peltzer, Karl; Matseke, Gladys; Mathebula, Audrey; Ramlagan, Shandir; Sifunda, Sibusiso; Prado, Guillermo Willy; Horigian, Viviana; Weiss, Stephen M; Jones, Deborah L

    2017-12-01

    The Joint United Nations Programme on HIV and AIDS proposed to reduce the vertical transmission of HIV from ∼72,200 to ∼8300 newly infected children by 2015 in South Africa (SA). However, cultural, infrastructural, and socio-economic barriers hinder the implementation of the prevention of mother-to-child transmission (PMTCT) protocol, and research on potential solutions to address these barriers in rural areas is particularly limited. This study sought to identify challenges and solutions to the implementation, uptake, and sustainability of the PMTCT protocol in rural SA. Forty-eight qualitative interviews, 12 focus groups discussions (n = 75), and one two-day workshop (n = 32 participants) were conducted with district directors, clinic leaders, staff, and patients from 12 rural clinics. The delivery and uptake of the PMTCT protocol was evaluated using the Consolidated Framework for Implementation Research (CFIR); 15 themes associated with challenges and solutions emerged. Intervention characteristics themes included PMTCT training and HIV serostatus disclosure. Outer-setting themes included facility space, health record management, and staff shortage; inner-setting themes included supply use and availability, staff-patient relationship, and transportation and scheduling. Themes related to characteristics of individuals included staff relationships, initial antenatal care visit, adherence, and culture and stigma. Implementation process themes included patient education, test results delivery, and male involvement. Significant gaps in care were identified in rural areas. Information obtained from participants using the CFIR framework provided valuable insights into solutions to barriers to PMTCT implementation. Continuously assessing and correcting PMTCT protocol implementation, uptake and sustainability appear merited to maximize HIV prevention.

  9. The Achilles’ heel of prevention to mother-to-child transmission of HIV: Protocol implementation, uptake, and sustainability

    Science.gov (United States)

    Rodriguez, Violeta J.; LaCabe, Richard P.; Privette, C. Kyle; Douglass, K. Marie; Peltzer, Karl; Matseke, Gladys; Mathebula, Audrey; Ramlagan, Shandir; Sifunda, Sibusiso; Prado, Guillermo “Willy”; Horigian, Viviana; Weiss, Stephen M.; Jones, Deborah L.

    2017-01-01

    Abstract The Joint United Nations Programme on HIV and AIDS proposed to reduce the vertical transmission of HIV from ∼72,200 to ∼8300 newly infected children by 2015 in South Africa (SA). However, cultural, infrastructural, and socio-economic barriers hinder the implementation of the prevention of mother-to-child transmission (PMTCT) protocol, and research on potential solutions to address these barriers in rural areas is particularly limited. This study sought to identify challenges and solutions to the implementation, uptake, and sustainability of the PMTCT protocol in rural SA. Forty-eight qualitative interviews, 12 focus groups discussions (n = 75), and one two-day workshop (n = 32 participants) were conducted with district directors, clinic leaders, staff, and patients from 12 rural clinics. The delivery and uptake of the PMTCT protocol was evaluated using the Consolidated Framework for Implementation Research (CFIR); 15 themes associated with challenges and solutions emerged. Intervention characteristics themes included PMTCT training and HIV serostatus disclosure. Outer-setting themes included facility space, health record management, and staff shortage; inner-setting themes included supply use and availability, staff–patient relationship, and transportation and scheduling. Themes related to characteristics of individuals included staff relationships, initial antenatal care visit, adherence, and culture and stigma. Implementation process themes included patient education, test results delivery, and male involvement. Significant gaps in care were identified in rural areas. Information obtained from participants using the CFIR framework provided valuable insights into solutions to barriers to PMTCT implementation. Continuously assessing and correcting PMTCT protocol implementation, uptake and sustainability appear merited to maximize HIV prevention. PMID:28922974

  10. Streptococcus pyogenes translocates across an epithelial barrier.

    Science.gov (United States)

    Sumitomo, Tomoko

    2017-01-01

    Streptococcus pyogenes is a β-hemolytic organism responsible for a wide variety of human diseases that commonly occur as self-limiting purulent diseases of the pharynx and skin. Although the occurrence of invasive infections by S. pyogenes is rare, mortality rates remain high even with progressive medical therapy. As a prerequisite for causing the severe invasive disease, S. pyogenes must invade underlying sterile tissues by translocating across the epithelial barrier. In this study, streptolysin S and SpeB were identified as the novel factors that facilitate bacterial translocation via degradation of intercellular junctions. Furthermore, we found that S. pyogenes exploits host plasminogen for acceleration of bacterial invasion into deeper tissues via tricellular tight junctions. Here, I would like to show our study on bacterial translocation across the epithelial barrier through paracellular route.

  11. The inner CSF-brain barrier

    DEFF Research Database (Denmark)

    Whish, Sophie; Dziegielewska, Katarzyna M; Møllgård, Kjeld

    2015-01-01

    consisting of neuroepithelial cells and later radial glial cells, is characterized by "strap" junctions, which limit the exchange of different sized molecules between cerebrospinal fluid and the brain parenchyma. Here we provide a systematic study of permeability properties of this inner cerebrospinal fluid-brain...... barrier during mouse development from embryonic day, E17 until adult. Results show that at fetal stages exchange across this barrier is restricted to the smallest molecules (286Da) and the diffusional restraint is progressively removed as the brain develops. By postnatal day P20, molecules the size......In the adult the interface between the cerebrospinal fluid and the brain is lined by the ependymal cells, which are joined by gap junctions. These intercellular connections do not provide a diffusional restrain between the two compartments. However, during development this interface, initially...

  12. Great Plains Wind Energy Transmission Development Project

    Energy Technology Data Exchange (ETDEWEB)

    Brad G. Stevens, P.E.; Troy K. Simonsen; Kerryanne M. Leroux

    2012-06-09

    In fiscal year 2005, the Energy & Environmental Research Center (EERC) received funding from the U.S. Department of Energy (DOE) to undertake a broad array of tasks to either directly or indirectly address the barriers that faced much of the Great Plains states and their efforts to produce and transmit wind energy at the time. This program, entitled Great Plains Wind Energy Transmission Development Project, was focused on the central goal of stimulating wind energy development through expansion of new transmission capacity or development of new wind energy capacity through alternative market development. The original task structure was as follows: Task 1 - Regional Renewable Credit Tracking System (later rescoped to Small Wind Turbine Training Center); Task 2 - Multistate Transmission Collaborative; Task 3 - Wind Energy Forecasting System; and Task 4 - Analysis of the Long-Term Role of Hydrogen in the Region. As carried out, Task 1 involved the creation of the Small Wind Turbine Training Center (SWTTC). The SWTTC, located Grand Forks, North Dakota, consists of a single wind turbine, the Endurance S-250, on a 105-foot tilt-up guyed tower. The S-250 is connected to the electrical grid on the 'load side' of the electric meter, and the power produced by the wind turbine is consumed locally on the property. Establishment of the SWTTC will allow EERC personnel to provide educational opportunities to a wide range of participants, including grade school through college-level students and the general public. In addition, the facility will allow the EERC to provide technical training workshops related to the installation, operation, and maintenance of small wind turbines. In addition, under Task 1, the EERC hosted two small wind turbine workshops on May 18, 2010, and March 8, 2011, at the EERC in Grand Forks, North Dakota. Task 2 involved the EERC cosponsoring and aiding in the planning of three transmission workshops in the midwest and western regions. Under Task

  13. Recent Transmission of Tuberculosis - United States, 2011-2014.

    Directory of Open Access Journals (Sweden)

    Courtney M Yuen

    Full Text Available Tuberculosis is an infectious disease that may result from recent transmission or from an infection acquired many years in the past; there is no diagnostic test to distinguish the two causes. Cases resulting from recent transmission are particularly concerning from a public health standpoint. To describe recent tuberculosis transmission in the United States, we used a field-validated plausible source-case method to estimate cases likely resulting from recent transmission during January 2011-September 2014. We classified cases as resulting from either limited or extensive recent transmission based on transmission cluster size. We used logistic regression to analyze patient characteristics associated with recent transmission. Of 26,586 genotyped cases, 14% were attributable to recent transmission, 39% of which were attributable to extensive recent transmission. The burden of cases attributed to recent transmission was geographically heterogeneous and poorly predicted by tuberculosis incidence. Extensive recent transmission was positively associated with American Indian/Alaska Native (adjusted prevalence ratio [aPR] = 3.6 (95% confidence interval [CI] 2.9-4.4, Native Hawaiian/Pacific Islander (aPR = 3.2, 95% CI 2.3-4.5, and black (aPR = 3.0, 95% CI 2.6-3.5 race, and homelessness (aPR = 2.3, 95% CI 2.0-2.5. Extensive recent transmission was negatively associated with foreign birth (aPR = 0.2, 95% CI 0.2-0.2. Tuberculosis control efforts should prioritize reducing transmission among higher-risk populations.

  14. Barriers to global health development: An international quantitative survey.

    Directory of Open Access Journals (Sweden)

    Bahr Weiss

    Full Text Available Global health's goal of reducing low-and-middle-income country versus high-income country health disparities faces complex challenges. Although there have been discussions of barriers, there has not been a broad-based, quantitative survey of such barriers.432 global health professionals were invited via email to participate in an online survey, with 268 (62% participating. The survey assessed participants' (A demographic and global health background, (B perceptions regarding 66 barriers' seriousness, (C detailed ratings of barriers designated most serious, (D potential solutions.Thirty-four (of 66 barriers were seen as moderately or more serious, highlighting the widespread, significant challenges global health development faces. Perceived barrier seriousness differed significantly across domains: Resource Limitations mean = 2.47 (0-4 Likert scale, Priority Selection mean = 2.20, Corruption, Lack of Competence mean = 1.87, Social and Cultural Barriers mean = 1.68. Some system-level predictors showed significant but relatively limited relations. For instance, for Global Health Domain, HIV and Mental Health had higher levels of perceived Social and Cultural Barriers than other GH Domains. Individual-level global health experience predictors had small but significant effects, with seriousness of (a Corruption, Lack of Competence, and (b Priority Selection barriers positively correlated with respondents' level of LMIC-oriented (e.g., weeks/year spent in LMIC but Academic Global Health Achievement (e.g., number of global health publications negatively correlated with overall barrier seriousness.That comparatively few system-level predictors (e.g., Organization Type were significant suggests these barriers may be relatively fundamental at the system-level. Individual-level and system-level effects do have policy implications; e.g., Priority Selection barriers were among the most serious, yet effects on seriousness of how LMIC-oriented a professional

  15. Barriers to global health development: An international quantitative survey.

    Science.gov (United States)

    Weiss, Bahr; Pollack, Amie Alley

    2017-01-01

    Global health's goal of reducing low-and-middle-income country versus high-income country health disparities faces complex challenges. Although there have been discussions of barriers, there has not been a broad-based, quantitative survey of such barriers. 432 global health professionals were invited via email to participate in an online survey, with 268 (62%) participating. The survey assessed participants' (A) demographic and global health background, (B) perceptions regarding 66 barriers' seriousness, (C) detailed ratings of barriers designated most serious, (D) potential solutions. Thirty-four (of 66) barriers were seen as moderately or more serious, highlighting the widespread, significant challenges global health development faces. Perceived barrier seriousness differed significantly across domains: Resource Limitations mean = 2.47 (0-4 Likert scale), Priority Selection mean = 2.20, Corruption, Lack of Competence mean = 1.87, Social and Cultural Barriers mean = 1.68. Some system-level predictors showed significant but relatively limited relations. For instance, for Global Health Domain, HIV and Mental Health had higher levels of perceived Social and Cultural Barriers than other GH Domains. Individual-level global health experience predictors had small but significant effects, with seriousness of (a) Corruption, Lack of Competence, and (b) Priority Selection barriers positively correlated with respondents' level of LMIC-oriented (e.g., weeks/year spent in LMIC) but Academic Global Health Achievement (e.g., number of global health publications) negatively correlated with overall barrier seriousness. That comparatively few system-level predictors (e.g., Organization Type) were significant suggests these barriers may be relatively fundamental at the system-level. Individual-level and system-level effects do have policy implications; e.g., Priority Selection barriers were among the most serious, yet effects on seriousness of how LMIC-oriented a professional was

  16. Planetary Transmission Diagnostics

    Science.gov (United States)

    Lewicki, David G. (Technical Monitor); Samuel, Paul D.; Conroy, Joseph K.; Pines, Darryll J.

    2004-01-01

    This report presents a methodology for detecting and diagnosing gear faults in the planetary stage of a helicopter transmission. This diagnostic technique is based on the constrained adaptive lifting algorithm. The lifting scheme, developed by Wim Sweldens of Bell Labs, is a time domain, prediction-error realization of the wavelet transform that allows for greater flexibility in the construction of wavelet bases. Classic lifting analyzes a given signal using wavelets derived from a single fundamental basis function. A number of researchers have proposed techniques for adding adaptivity to the lifting scheme, allowing the transform to choose from a set of fundamental bases the basis that best fits the signal. This characteristic is desirable for gear diagnostics as it allows the technique to tailor itself to a specific transmission by selecting a set of wavelets that best represent vibration signals obtained while the gearbox is operating under healthy-state conditions. However, constraints on certain basis characteristics are necessary to enhance the detection of local wave-form changes caused by certain types of gear damage. The proposed methodology analyzes individual tooth-mesh waveforms from a healthy-state gearbox vibration signal that was generated using the vibration separation (synchronous signal-averaging) algorithm. Each waveform is separated into analysis domains using zeros of its slope and curvature. The bases selected in each analysis domain are chosen to minimize the prediction error, and constrained to have the same-sign local slope and curvature as the original signal. The resulting set of bases is used to analyze future-state vibration signals and the lifting prediction error is inspected. The constraints allow the transform to effectively adapt to global amplitude changes, yielding small prediction errors. However, local wave-form changes associated with certain types of gear damage are poorly adapted, causing a significant change in the

  17. Nurse-patient communication barriers in Iranian nursing.

    Science.gov (United States)

    Anoosheh, M; Zarkhah, S; Faghihzadeh, S; Vaismoradi, M

    2009-06-01

    Providing effective communication with patients is an essential aspect of nursing care. Understanding the barriers that inhibit nurse-patient communication can provide an opportunity to eliminate them. To investigate nurse-patient and environment-related communication barriers perceived by patients and nurses in Iranian nursing. A descriptive survey was carried out in three randomly selected educational hospitals in a large urban city in Iran. Data were collected by questionnaire; the study sample consisted of 61 patients and 75 nurses. Participants were asked to rate the importance of each communication barriers item. Finally, data were analysed using descriptive statistics, and to compare the perceived importance of communication barriers between patients and nurses, item means were calculated and the t-test for independent samples was applied. Similarities and differences between the two groups were identified. According to nurses' views, 'heavy nursing workload', 'hard nursing tasks' and 'lack of welfare facilities for nurses' were the main communication barriers. From patients' views, 'unfamiliarity of nurses with dialect', 'having contagious diseases' and 'sex differences between nurses and patients' were determined as the main communication barriers. The shared communication barriers were 'age difference', 'social class difference' and 'having contagious diseases'. It can be concluded that nursing managers and healthcare system planners should focus on eliminating or modifying the barriers stated by the two groups, particularly the shared ones. It is suggested that understanding the cultural aspects of nurse-patient communication barriers in various contexts can help nurses. The study relied on self-report by a limited sample of nurses and patients. The responses should now be tested by a larger sample and then by empirical research into actual practice in order to test whether the nurses' and patients' perceived ideas of communication barriers are

  18. Market and policy barriers to energy storage deployment :

    Energy Technology Data Exchange (ETDEWEB)

    Bhatnagar, Dhruv; Currier, Aileen B.; Hernandez, Jacquelynne; Ma, Ookie; Kirby, Brendan

    2013-09-01

    Electric energy storage technologies have recently been in the spotlight, discussed as essential grid assets that can provide services to increase the reliability and resiliency of the grid, including furthering the integration of variable renewable energy resources. Though they can provide numerous grid services, there are a number of factors that restrict their current deployment. The most significant barrier to deployment is high capital costs, though several recent deployments indicate that capital costs are decreasing and energy storage may be the preferred economic alternative in certain situations. However, a number of other market and regulatory barriers persist, limiting further deployment. These barriers can be categorized into regulatory barriers, market (economic) barriers, utility and developer business model barriers, crosscutting barriers and technology barriers. This report, through interviews with stakeholders and review of regulatory filings in four regions roughly representative of the United States, identifies the key barriers restricting further energy storage development in the country. The report also includes a discussion of possible solutions to address these barriers and a review of initiatives around the country at the federal, regional and state levels that are addressing some of these issues. Energy storage could have a key role to play in the future grid, but market and regulatory issues have to be addressed to allow storage resources open market access and compensation for the services they are capable of providing. Progress has been made in this effort, but much remains to be done and will require continued engagement from regulators, policy makers, market operators, utilities, developers and manufacturers.

  19. Research and Transmission

    Directory of Open Access Journals (Sweden)

    Denise Pumain

    2001-01-01

    Full Text Available The present situation provides a challenge for us to reconsider the necessary link between science and pedagogy, between research and the transmission of knowledge. The Ministry of National education has just inaugurated a broad consultation of teachers on every level with a view to modernising and giving coherence to the programs of secondary education. Armand Frémont will head the group of experts responsible for history and geography. Is this a coincidence? The changeover in the jury for t...

  20. Coaxial transmission line - Equalization

    International Nuclear Information System (INIS)

    Bonnerue, J.L.; Fremont, Jacques; Haubtmann, Jack; Pillon, Gerard.

    1981-09-01

    The transmission of electrical signal through a coaxial line is not perfect and signal distortions are increased as much as the frequency spectrum is extended. We have designed and achieved passive filters (named equalizers) with transfer functions which are inverse of coaxial transfer functions. Doing so our attempt is to avoid definitive loss of information in the recorded data. The main feature of our equalization method lies in the fact it could be either an electrical or a numerical correction or both of them. Some examples in the use of this technique are also proposed [fr

  1. Economy of electric power transmission

    International Nuclear Information System (INIS)

    Manzoni, G.; Delfanti, M.

    2008-01-01

    An analysis is presented of the impact of H V and Ehv transmission costs on the final value of the kWh supplied, with reference both to transmission systems of the European type and to long distance point-to-point transmission links. The analysis is extended to A C transmission by underground cables and to Hvdc submarine and aerial links. In the European power system, the impact of transmission costs results to be usually modest, but it may become important in the case of network congestions [it

  2. Age Limits.

    Science.gov (United States)

    Antfolk, Jan

    2017-03-01

    Whereas women of all ages prefer slightly older sexual partners, men-regardless of their age-have a preference for women in their 20s. Earlier research has suggested that this difference between the sexes' age preferences is resolved according to women's preferences. This research has not, however, sufficiently considered that the age range of considered partners might change over the life span. Here we investigated the age limits (youngest and oldest) of considered and actual sex partners in a population-based sample of 2,655 adults (aged 18-50 years). Over the investigated age span, women reported a narrower age range than men and women tended to prefer slightly older men. We also show that men's age range widens as they get older: While they continue to consider sex with young women, men also consider sex with women their own age or older. Contrary to earlier suggestions, men's sexual activity thus reflects also their own age range, although their potential interest in younger women is not likely converted into sexual activity. Compared to homosexual men, bisexual and heterosexual men were more unlikely to convert young preferences into actual behavior, supporting female-choice theory.

  3. Age Limits

    Directory of Open Access Journals (Sweden)

    Jan Antfolk

    2017-01-01

    Full Text Available Whereas women of all ages prefer slightly older sexual partners, men—regardless of their age—have a preference for women in their 20s. Earlier research has suggested that this difference between the sexes’ age preferences is resolved according to women’s preferences. This research has not, however, sufficiently considered that the age range of considered partners might change over the life span. Here we investigated the age limits (youngest and oldest of considered and actual sex partners in a population-based sample of 2,655 adults (aged 18-50 years. Over the investigated age span, women reported a narrower age range than men and women tended to prefer slightly older men. We also show that men’s age range widens as they get older: While they continue to consider sex with young women, men also consider sex with women their own age or older. Contrary to earlier suggestions, men’s sexual activity thus reflects also their own age range, although their potential interest in younger women is not likely converted into sexual activity. Compared to homosexual men, bisexual and heterosexual men were more unlikely to convert young preferences into actual behavior, supporting female-choice theory.

  4. 10-year transmission system plan, 2005-2014

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-12-01

    This 10-year transmission plan for the Alberta Electric System Operator (AESO) provides market participants, customers and stakeholders with a view of Alberta's transmission system development over the next decade. Information on current and forecasted market participant needs are outlined along with infrastructure developments needed to address them. The plan allows for constraint free access to power generation and loads, and facilitates an open and efficient electricity market while promoting system reliability. Although the current transmission system has served the province of Alberta well for several years, the addition of new load and generation has caused congestion and stress in some parts of the system, resulting in voltage and stability problems and transmission system losses. The new plan includes options to reinforce the system and mitigate problems such as scheduling out of service equipment for routine maintenance and interchange capabilities to neighbouring jurisdictions. The plan is based on the scenario that most of the generation will occur in the Lake Wabamun, Edmonton and Fort McMurray areas. It addresses transmission reinforcements needed to connect new generation capabilities and deliver the power to areas where it is needed. It identifies specific pro-active solutions for the acquisition of rights-of-way for 500 kV facilities in order that the plan be implemented in a timely manner and so that the lack of transmission does not become a barrier to the development of new generation. 17 tabs., 18 figs.

  5. Evaluation of the Zoonotic Potential of Transmissible Mink Encephalopathy

    Directory of Open Access Journals (Sweden)

    Paul Brown

    2013-07-01

    Full Text Available Successful transmission of Transmissible Mink Encephalopathy (TME to cattle supports the bovine hypothesis for the still controversial origin of TME outbreaks. Human and primate susceptibility to classical Bovine Spongiform Encephalopathy (c-BSE and the transmissibility of L-type BSE to macaques indicate a low cattle-to-primate species barrier. We therefore evaluated the zoonotic potential of cattle-adapted TME. In less than two years, this strain induced in cynomolgus macaques a neurological disease similar to L-BSE but distinct from c-BSE. TME derived from another donor species (raccoon induced a similar disease with even shorter incubation periods. L-BSE and cattle-adapted TME were also transmissible to transgenic mice expressing human prion protein (PrP. Secondary transmissions to transgenic mice expressing bovine PrP maintained the features of the three tested bovine strains (cattle TME, c-BSE and L-BSE regardless of intermediate host. Thus, TME is the third animal prion strain transmissible to both macaques and humanized transgenic mice, suggesting zoonotic potentials that should be considered in the risk analysis of animal prion diseases for human health. Moreover, the similarities between TME and L-BSE are highly suggestive of a link between these strains, and therefore the possible presence of L-BSE for many decades prior to its identification in USA and Europe.

  6. Evaluation of the Zoonotic Potential of Transmissible Mink Encephalopathy

    Science.gov (United States)

    Comoy, Emmanuel E.; Mikol, Jacqueline; Ruchoux, Marie-Madeleine; Durand, Valérie; Luccantoni-Freire, Sophie; Dehen, Capucine; Correia, Evelyne; Casalone, Cristina; Richt, Juergen A.; Greenlee, Justin J.; Torres, Juan Maria; Brown, Paul; Deslys, Jean-Philippe

    2013-01-01

    Successful transmission of Transmissible Mink Encephalopathy (TME) to cattle supports the bovine hypothesis for the still controversial origin of TME outbreaks. Human and primate susceptibility to classical Bovine Spongiform Encephalopathy (c-BSE) and the transmissibility of L-type BSE to macaques indicate a low cattle-to-primate species barrier. We therefore evaluated the zoonotic potential of cattle-adapted TME. In less than two years, this strain induced in cynomolgus macaques a neurological disease similar to L-BSE but distinct from c-BSE. TME derived from another donor species (raccoon) induced a similar disease with even shorter incubation periods. L-BSE and cattle-adapted TME were also transmissible to transgenic mice expressing human prion protein (PrP). Secondary transmissions to transgenic mice expressing bovine PrP maintained the features of the three tested bovine strains (cattle TME, c-BSE and L-BSE) regardless of intermediate host. Thus, TME is the third animal prion strain transmissible to both macaques and humanized transgenic mice, suggesting zoonotic potentials that should be considered in the risk analysis of animal prion diseases for human health. Moreover, the similarities between TME and L-BSE are highly suggestive of a link between these strains, and therefore the possible presence of L-BSE for many decades prior to its identification in USA and Europe. PMID:25437205

  7. Informal export barriers and poverty

    OpenAIRE

    Porto, Guido G.

    2004-01-01

    The author investigates the poverty impacts of informal export barriers like transport costs, cumbersome customs practices, costly regulations, and bribes. He models these informal barriers as export taxes that distort the efficient allocation of resources. In low-income agricultural economies, this distortion lowers wages and household agricultural income, thereby leading to higher pover...

  8. Barriers to Women in Science

    Science.gov (United States)

    Butler, Rosemary

    2013-01-01

    The Presiding Officer of the National Assembly for Wales, Rosemary Butler AM, has put the issue of barriers to women in public life at the top of the political agenda in Wales. She has held sessions with women across Wales to find out what those barriers are and how they can be tackled. On International Women's Day in February, she invited…

  9. Seismic waves and seismic barriers

    Science.gov (United States)

    Kuznetsov, S. V.

    2011-05-01

    The basic idea of seismic barrier is to protect an area occupied by a building or a group of buildings from seismic waves. Depending on nature of seismic waves that are most probable in a specific region, different kinds of seismic barriers are suggested. For example, vertical barriers resembling a wall in a soil can protect from Rayleigh and bulk waves. The FEM simulation reveals that to be effective, such a barrier should be (i) composed of layers with contrast physical properties allowing "trapping" of the wave energy inside some of the layers, and (ii) depth of the barrier should be comparable or greater than the considered seismic wave length. Another type of seismic barrier represents a relatively thin surface layer that prevents some types of surface seismic waves from propagating. The ideas for these barriers are based on one Chadwick's result concerning non-propagation condition for Rayleigh waves in a clamped half-space, and Love's theorem that describes condition of non-existence for Love waves. The numerical simulations reveal that to be effective the length of the horizontal barriers should be comparable to the typical wavelength.

  10. Structure information from fusion barriers

    Indian Academy of Sciences (India)

    It is shown that the analysis of fusion barrier distributions is not always an unambiguous test or a 'fingerprint' of the structure information of the colliding nuclei. Examples are presented with same fusion barrier distributions for nuclei having different structures. The fusion excitation functions for 16O+208Pb, using the coupled ...

  11. BARRIERS OF STRATEGIC ALLIANCES ORGANIZATION

    Directory of Open Access Journals (Sweden)

    Vladislav M. Sannikov

    2014-01-01

    Full Text Available General barriers of organization of different types of strategic alliances have beenconsidered in the article. There are several recommendations for overcoming themin cases of international alliances, and in case of work in one state. The article also identified goals and tasks of single coordination center of alliance to overcome organization barriers.

  12. Organizational Barriers to Transition: Summary.

    Science.gov (United States)

    Haynes, John; Justice, Thomas I., Ed.

    This study sought to identify the barriers that negatively impact the ability of disabled youth to successfully make a transition from school into employment and a quality adult life, and sought to specifically define organizational disincentives to successful transition. Current research is reviewed relating to organizational barriers to…

  13. Dynamics of a scrapie outbreak in a flock of Romanov sheep-estimation of transmission parameters

    NARCIS (Netherlands)

    Hagenaars, T.H.J.; Donelly, C.A.; Ferguson, N.M.; Anderson, R.M.

    2003-01-01

    Knowledge of epidemiological mechanisms and parameters underlying scrapie transmission in sheep flocks remains very limited at present. Here we introduce a method for fitting stochastic transmission models to outbreak data to estimate bounds on key transmission parameters. We apply this method to

  14. Epistemological barriers to radical behaviorism.

    Science.gov (United States)

    O'Donohue, W T; Callaghan, G M; Ruckstuhl, L E

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers.

  15. Epistemological barriers to radical behaviorism

    Science.gov (United States)

    O'Donohue, William T.; Callaghan, Glenn M.; Ruckstuhl, L. E.

    1998-01-01

    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers. PMID:22478314

  16. Barriers for recess physical activity

    DEFF Research Database (Denmark)

    Pawlowski, Charlotte Skau; Tjørnhøj-Thomsen, Tine; Schipperijn, Jasper

    2014-01-01

    . This was verified by a thematic analysis of transcripts from the open discussions and go-along interviews. RESULTS: The most frequently identified barriers for both boys and girls were weather, conflicts, lack of space, lack of play facilities and a newly-found barrier, use of electronic devices. While boys......BACKGROUND: Many children, in particular girls, do not reach the recommended amount of daily physical activity. School recess provides an opportunity for both boys and girls to be physically active, but barriers to recess physical activity are not well understood. This study explores gender...... differences in children's perceptions of barriers to recess physical activity. Based on the socio-ecological model four types of environmental barriers were distinguished: natural, social, physical and organizational environment. METHODS: Data were collected through 17 focus groups (at 17 different schools...

  17. Overwash threshold experiment for gravel barriers

    Science.gov (United States)

    Matias, Ana; Williams, Jon; Bradbury, Andrew; Masselink, Gerhard; Ferreira, Óscar

    2010-05-01

    action show those formulas underestimate the run-up limit. The discrepancy, which can reach almost 1m, is attributed to several causes, including: (1) scale effects of the prototype; (2) applicability of most run-up formulae only to sandy barriers and beaches; and (3) important, infrequent (K., Bradbury, A., 2008. A laboratory study of overtopping and breaching of shingle barrier beaches. Proc. Coastal Engineering, Hannover, Germany, pp. 1497-1508. Orford, J. And Carter, R.W.G., 1982. Crestal overtop and washover sedimentation on a fringing sandy gravel barrier coast, Carnsore Point, Southeast Ireland. J. Sedim. Petrology, 52, 265-278. Powell, K.A., 1990. Predicting short term profile response for shingle beaches. HR Wallingford SR Report, vol. 219. Stockdon, H.F., Sallenger, A.H., Holman, R.A., Howd, P.A., 2007. A simple model for the spatially-variable coastal response to hurricanes. Mar. Geol., 238, 1-20. Williams, J.J., Masselink, G., Buscombe, D., Turner, I.L., Matias, A., Ferreira, A. Metje, N., Coates, L., Chapman, D., Bradbury, A., Albers, A. & Pan, S., 2009. BARDEX (Barrier Dynamics Experiment): taking the beach into the laboratory. J. Coastal Res., SI 56, 158-162.

  18. Hanford Protective Barriers Program asphalt barrier studies -- FY 1988

    International Nuclear Information System (INIS)

    Freeman, H.D.; Gee, G.W.

    1989-05-01

    The Hanford Protective Barrier (HPB) Program is evaluating alternative barriers to provide a means of meeting stringent water infiltration requirements. One type of alternative barrier being considered is an asphalt-based layer, 1.3 to 15 cm thick, which has been shown to be very effective as a barrier for radon gas and, hence, should be equally effective as a barrier for the larger molecules of water. Fiscal Year 1988 studies focused on the selection and formulation of the most promising asphalt materials for further testing in small-tube lysimeters. Results of laboratory-scale formulation and hydraulic conductivity tests led to the selection of a rubberized asphalt material and an admixture of 24 wt% asphalt emulsion and concrete sand as the two barriers for lysimeter testing. Eight lysimeters, four each containing the two asphalt treatments, were installed in the Small Tube Lysimeter Facility on the Hanford Site. The lysimeter tests allow the performance of these barrier formulations to be evaluated under more natural environmental conditions

  19. (Limiting the greenhouse effect)

    Energy Technology Data Exchange (ETDEWEB)

    Rayner, S.

    1991-01-07

    Traveler attended the Dahlem Research Conference organized by the Freien Universitat, Berlin. The subject of the conference was Limiting the Greenhouse Effect: Options for Controlling Atmospheric CO{sub 2} Accumulation. Like all Dahlem workshops, this was a meeting of scientific experts, although the disciplines represented were broader than usual, ranging across anthropology, economics, international relations, forestry, engineering, and atmospheric chemistry. Participation by scientists from developing countries was limited. The conference was divided into four multidisciplinary working groups. Traveler acted as moderator for Group 3 which examined the question What knowledge is required to tackle the principal social and institutional barriers to reducing CO{sub 2} emissions'' The working rapporteur was Jesse Ausubel of Rockefeller University. Other working groups examined the economic costs, benefits, and technical feasibility of options to reduce emissions per unit of energy service; the options for reducing energy use per unit of GNP; and the significant of linkage between strategies to reduce CO{sub 2} emissions and other goals. Draft reports of the working groups are appended. Overall, the conference identified a number of important research needs in all four areas. It may prove particularly important in bringing the social and institutional research needs relevant to climate change closer to the forefront of the scientific and policy communities than hitherto.

  20. Barriers to health care for undocumented immigrants: a literature review

    Science.gov (United States)

    Hacker, Karen; Anies, Maria; Folb, Barbara L; Zallman, Leah

    2015-01-01

    With the unprecedented international migration seen in recent years, policies that limit health care access have become prevalent. Barriers to health care for undocumented immigrants go beyond policy and range from financial limitations, to discrimination and fear of deportation. This paper is aimed at reviewing the literature on barriers to health care for undocumented immigrants and identifying strategies that have or could be used to address these barriers. To address study questions, we conducted a literature review of published articles from the last 10 years in PubMed using three main concepts: immigrants, undocumented, and access to health care. The search yielded 341 articles of which 66 met study criteria. With regard to barriers, we identified barriers in the policy arena focused on issues related to law and policy including limitations to access and type of health care. These varied widely across countries but ultimately impacted the type and amount of health care any undocumented immigrant could receive. Within the health system, barriers included bureaucratic obstacles including paperwork and registration systems. The alternative care available (safety net) was generally limited and overwhelmed. Finally, there was evidence of widespread discriminatory practices within the health care system itself. The individual level focused on the immigrant’s fear of deportation, stigma, and lack of capital (both social and financial) to obtain services. Recommendations identified in the papers reviewed included advocating for policy change to increase access to health care for undocumented immigrants, providing novel insurance options, expanding safety net services, training providers to better care for immigrant populations, and educating undocumented immigrants on navigating the system. There are numerous barriers to health care for undocumented immigrants. These vary by country and frequently change. Despite concerns that access to health care attracts

  1. Development of engineered barrier

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwan Sik; Cho, Won Jin; Lee, Jae Owan; Kim, Seung Soo; Kang, Mu Ja

    1999-03-01

    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  2. Alternative geochemical barrier materials

    International Nuclear Information System (INIS)

    1991-07-01

    Previous investigations of the effects of neutralization and reduction on uranium mill tailings pore fluids by the Technical Support Contractor indicated that arsenic, selenium, and molybdenum continue to remain in solution in all but reducing conditions. These hazardous constituents are present in groundwaters as oxyanions and, therefore, are not expected to be removed by adsorption into clays and most other soil constituents. It was decided to investigate the attenuation capacity of two commonly available crystalline iron oxides, taconite and scoria, and a zeolite, a network aluminosilicate with a cage structure. Columns of the candidate materials were exposed to solutions of individual constituents, including arsenic, molybdenum, selenium, and, uranium, and to the spiked tailings pore fluid from the Bodo Canyon disposal cell near Durango, Colorado. In addition to the single material columns, a homogeneous blend of the three materials and layers of the materials were exposed to spiked tailings pore fluids. The results of these experiments indicate that with the exception of molybdenum, the constituents of concern are attenuated by the taconite; however, they are not sufficiently attenuated to meet the groundwater protection standards applicable to the UMTRA Project. Therefore, the candidate barrier materials did not prove to be useful to the UMTRA Project for the cleanup of groundwaters

  3. Noninvasive evaluation of the barrier properties of the skin

    Directory of Open Access Journals (Sweden)

    Utz S.R.

    2014-09-01

    Full Text Available Skin as an organ of protection covers the body and accomplishes multiple defensive functions. The intact skin represents a barrier to the uncontrolled loss of water, proteins, and plasma components from the organism. Due to its complex structure, the epidermal barrier with its major component, stratum corneum, is the rate-limiting unit for the penetration of exogenous substances through the skin. The epidermal barrier is not a static structure. The permeability barrier status can be modified by different external and internal factors such as climate, physical stressors, and a number of skin and systemic diseases. Today, different non-invasive approaches are used to monitor the skin barrier physical properties in vivo. The quantification of parameters such as transepidermal water loss, stratum corneum hydration, and skin surface acidity is essential for the integral evaluation of the epidermal barrier status. This paper will allow the readership to get acquainted with the non-invasive, in vivo methods for the investigation of the skin barrier.

  4. Hanford prototype-barrier status report: FY 1995

    Energy Technology Data Exchange (ETDEWEB)

    Gee, G.W.; Ward, A.L.; Gilmore, B.G.; Ligotke, M.W.; Link, S.O.

    1995-11-01

    Surface barriers (or covers) have been proposed for use at the Hanford Site as a means to isolate certain waste sites that, for reasons of cost or worker safety or both, may not be exhumed. Surface barriers are intende to isolated the wastes from the accessible environment and to provide long-term protection to future populations that might use the Hanford Site. Currently, no ``proven`` long-term barrier system is available. For this reason, the Hanford Site Permanent Isolation Surface-Barrier Development Program (BDP) was organized to develop the technology needed to provide long-term surface barrier capability for the Hanford Site for the US Department of Energy (DOE). Designs have been proposed to meet the most stringent needs for long-term waste disposal. The objective of the current barrier design is to use natural materials to develop a protective barrier system that isolates wastes for at least 1000 years by limiting water, plant, animal, and human intrusion; and minimizing erosion. The design criteria for water drainage has been set at 0.5 mm/yr. While other design criteria are more qualitative, it is clear that waste isolation for an extended time is the prime objective of the design. Constructibility and performance. are issues that can be tested and dealt with by evaluating prototype designs prior to extensive construction and deployment of covers for waste sites at Hanford.

  5. Small passenger car transmission test: Mercury Lynx ATX transmission

    Energy Technology Data Exchange (ETDEWEB)

    Bujold, M P

    1981-09-01

    The small passenger car transmission test was initiated to supply electric vehicle manufacturers with technical information regarding the performance of commercially available transmissions. This information would enable EV manufacturers to design a more energy efficient vehicle. With this information the manufacturers would be able to estimate vehicle driving range as well as speed and torque requirements for specific road load performance characteristics. This report covers the 1981 Mercury Lynx ATX transaxle. This transmission was tested per a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these test conditions the transmission attained maximum efficiencies in the 93% range for drive performance tests. The major results of this test are the torque, speed and efficiency curves which are located in the data section of this report. These graphs map performance characteristics for the Mercury Lynx ATX transmission.

  6. Small passenger car transmission test-Chevrolet 200 transmission

    Science.gov (United States)

    Bujold, M. P.

    1980-01-01

    The small passenger car transmission was tested to supply electric vehicle manufacturers with technical information regarding the performance of commerically available transmissions which would enable them to design a more energy efficient vehicle. With this information the manufacturers could estimate vehicle driving range as well as speed and torque requirements for specific road load performance characteristics. A 1979 Chevrolet Model 200 automatic transmission was tested per a passenger car automatic transmission test code (SAE J651b) which required drive performance, coast performance, and no load test conditions. The transmission attained maximum efficiencies in the mid-eighty percent range for both drive performance tests and coast performance tests. Torque, speed and efficiency curves map the complete performance characteristics for Chevrolet Model 200 transmission.

  7. Hanford Permanent Isolation Barrier Program: Asphalt technology test plan

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, H.D.; Romine, R.A.

    1994-05-01

    The Hanford Permanent Isolation Barriers use engineered layers of natural materials to create an integrated structure with backup protective features. The objective of current designs is to develop a maintenance-free permanent barrier that isolates wastes for a minimum of 1000 years by limiting water drainage to near-zero amounts. Asphalt is being used as an impermeable water diversion layer to provide a redundant layer within the overall barrier design. Data on asphalt barrier properties in a buried environment are not available for the required 100-year time frame. The purpose of this test plan is to outline the activities planned to obtain data with which to estimate performance of the asphalt layers.

  8. Barriers to Asthma Management for School Nurses: An Integrative Review.

    Science.gov (United States)

    Hanley Nadeau, Ellen; Toronto, Coleen E

    2016-04-01

    Childhood asthma is a growing health concern. Asthma is the most common chronic illness of childhood and a leading cause of emergency room visits, hospitalizations, and school absenteeism. School nurses play a valuable role in asthma management. The purpose of this integrative review is to examine barriers to asthma management for school nurses in the school setting. Findings revealed multiple barriers school nurses encounter in managing asthma. Six themes emerged that included lack of resources and support, insufficient time, communication challenges, limited knowledge, and lack of awareness of school nurses' expertise. Students, parents, primary care physicians, school administration, staff, and school nurses themselves all play a role in constructing barriers to asthma management. There is a need for school nurses and school nurse leaders to focus efforts to develop strategies to overcome barriers to ensure evidence-based, best practice management of asthma in the school setting. © The Author(s) 2015.

  9. Trends in drug delivery through tissue barriers containing tight junctions.

    Science.gov (United States)

    Tscheik, Christian; Blasig, Ingolf E; Winkler, Lars

    2013-04-01

    A limitation in the uptake of many drugs is the restricted permeation through tissue barriers. There are two general ways to cross barriers formed by cell layers: by transcytosis or by diffusion through the intercellular space. In the latter, tight junctions (TJs) play the decisive role in the regulation of the barrier permeability. Thus, transient modulation of TJs is a potent strategy to improve drug delivery. There have been extensive studies on surfactant-like absorption enhancers. One of the most effective enhancers found is sodium caprate. However, this modulates TJs in an unspecific fashion. A novel approach would be the specific modulation of TJ-associated marvel proteins and claudins, which are the main structural components of the TJs. Recent studies have identified synthetic peptidomimetics and RNA interference techniques to downregulate the expression of targeted TJ proteins. This review summarizes current progress and discusses the impact on TJs' barrier function.

  10. Types and Severities of Export Barriers: Evidence from Indonesian SMEs

    Directory of Open Access Journals (Sweden)

    Mohamad Dian Revindo

    2018-03-01

    Full Text Available Small and Medium-sized Enterprises (SMEs are more constrained to export than their large counterparts and SMEs' limited participation in export market is more prevalent in developing than in developed countries. Extant literature suggests that SMEs encounter a set of export inhibiting factors distinct to those faced by large firms and therefore accurate identification of export barriers is crucial in fostering SMEs export. This study investigates the export barriers faced by Indonesian SMEs. The evidences were collected from 271 exporting SMEs and 226 non-exporting SMEs in seven provinces in Jawa, Madura and Bali regions. The results show that the types and severities of export barriers perceived or encountered by SMEs vary across export stages and across products/industries. Further, export barriers can be distinguished by their general or specific nature. The policy and managerial implications of the findings are discussed.

  11. Hanford Permanent Isolation Barrier Program: Asphalt technology test plan

    International Nuclear Information System (INIS)

    Freeman, H.D.; Romine, R.A.

    1994-05-01

    The Hanford Permanent Isolation Barriers use engineered layers of natural materials to create an integrated structure with backup protective features. The objective of current designs is to develop a maintenance-free permanent barrier that isolates wastes for a minimum of 1000 years by limiting water drainage to near-zero amounts. Asphalt is being used as an impermeable water diversion layer to provide a redundant layer within the overall barrier design. Data on asphalt barrier properties in a buried environment are not available for the required 100-year time frame. The purpose of this test plan is to outline the activities planned to obtain data with which to estimate performance of the asphalt layers

  12. Flexible barrier film, method of forming same, and organic electronic device including same

    Science.gov (United States)

    Blizzard, John; Tonge, James Steven; Weidner, William Kenneth

    2013-03-26

    A flexible barrier film has a thickness of from greater than zero to less than 5,000 nanometers and a water vapor transmission rate of no more than 1.times.10.sup.-2 g/m.sup.2/day at 22.degree. C. and 47% relative humidity. The flexible barrier film is formed from a composition, which comprises a multi-functional acrylate. The composition further comprises the reaction product of an alkoxy-functional organometallic compound and an alkoxy-functional organosilicon compound. A method of forming the flexible barrier film includes the steps of disposing the composition on a substrate and curing the composition to form the flexible barrier film. The flexible barrier film may be utilized in organic electronic devices.

  13. Catchment management and the Great Barrier Reef.

    Science.gov (United States)

    Brodie, J; Christie, C; Devlin, M; Haynes, D; Morris, S; Ramsay, M; Waterhouse, J; Yorkston, H

    2001-01-01

    Pollution of coastal regions of the Great Barrier Reef is dominated by runoff from the adjacent catchment. Catchment land-use is dominated by beef grazing and cropping, largely sugarcane cultivation, with relatively minor urban development. Runoff of sediment, nutrients and pesticides is increasing and for nitrogen is now four times the natural amount discharged 150 years ago. Significant effects and potential threats are now evident on inshore reefs, seagrasses and marine animals. There is no effective legislation or processes in place to manage agricultural pollution. The Great Barrier Reef Marine Park Act does not provide effective jurisdiction on the catchment. Queensland legislation relies on voluntary codes and there is no assessment of the effectiveness of the codes. Integrated catchment management strategies, also voluntary, provide some positive outcomes but are of limited success. Pollutant loads are predicted to continue to increase and it is unlikely that current management regimes will prevent this. New mechanisms to prevent continued degradation of inshore ecosystems of the Great Barrier Reef World Heritage Area are urgently needed.

  14. The barrier within: endothelial transport of hormones.

    Science.gov (United States)

    Kolka, Cathryn M; Bergman, Richard N

    2012-08-01

    Hormones are involved in a plethora of processes including development and growth, metabolism, mood, and immune responses. These essential functions are dependent on the ability of the hormone to access its target tissue. In the case of endocrine hormones that are transported through the blood, this often means that the endothelium must be crossed. Many studies have shown that the concentrations of hormones and nutrients in blood can be very different from those surrounding the cells on the tissue side of the blood vessel endothelium, suggesting that transport across this barrier can be rate limiting for hormone action. This transport can be regulated by altering the surface area of the blood vessel available for diffusion through to the underlying tissue or by the permeability of the endothelium. Many hormones are known to directly or indirectly affect the endothelial barrier, thus affecting their own distribution to their target tissues. Dysfunction of the endothelial barrier is found in many diseases, particularly those associated with the metabolic syndrome. The interrelatedness of hormones may help to explain why the cluster of diseases in the metabolic syndrome occur together so frequently and suggests that treating the endothelium may ameliorate defects in more than one disease. Here, we review the structure and function of the endothelium, its contribution to the function of hormones, and its involvement in disease.

  15. The Barrier Within: Endothelial Transport of Hormones

    Science.gov (United States)

    Kolka, Cathryn M.; Bergman, Richard N.

    2015-01-01

    Hormones are involved in a plethora of processes including development and growth, metabolism, mood, and immune responses. These essential functions are dependent on the ability of the hormone to access its target tissue. In the case of endocrine hormones that are transported through the blood, this often means that the endothelium must be crossed. Many studies have shown that the concentrations of hormones and nutrients in blood can be very different from those surrounding the cells on the tissue side of the blood vessel endothelium, suggesting that transport across this barrier can be rate limiting for hormone action. This transport can be regulated by altering the surface area of the blood vessel available for diffusion through to the underlying tissue or by the permeability of the endothelium. Many hormones are known to directly or indirectly affect the endothelial barrier, thus affecting their own distribution to their target tissues. Dysfunction of the endothelial barrier is found in many diseases, particularly those associated with the metabolic syndrome. The interrelatedness of hormones may help to explain why the cluster of diseases in the metabolic syndrome occur together so frequently and suggests that treating the endothelium may ameliorate defects in more than one disease. Here, we review the structure and function of the endothelium, its contribution to the function of hormones, and its involvement in disease. PMID:22875454

  16. Almost there: transmission routes of bacterial symbionts between trophic levels.

    Directory of Open Access Journals (Sweden)

    Elad Chiel

    Full Text Available Many intracellular microbial symbionts of arthropods are strictly vertically transmitted and manipulate their host's reproduction in ways that enhance their own transmission. Rare horizontal transmission events are nonetheless necessary for symbiont spread to novel host lineages. Horizontal transmission has been mostly inferred from phylogenetic studies but the mechanisms of spread are still largely a mystery. Here, we investigated transmission of two distantly related bacterial symbionts--Rickettsia and Hamiltonella--from their host, the sweet potato whitefly, Bemisia tabaci, to three species of whitefly parasitoids: Eretmocerus emiratus, Eretmocerus eremicus and Encarsia pergandiella. We also examined the potential for vertical transmission of these whitefly symbionts between parasitoid generations. Using florescence in situ hybridization (FISH and transmission electron microscopy we found that Rickettsia invades Eretmocerus larvae during development in a Rickettsia-infected host, persists in adults and in females, reaches the ovaries. However, Rickettsia does not appear to penetrate the oocytes, but instead is localized in the follicular epithelial cells only. Consequently, Rickettsia is not vertically transmitted in Eretmocerus wasps, a result supported by diagnostic polymerase chain reaction (PCR. In contrast, Rickettsia proved to be merely transient in the digestive tract of Encarsia and was excreted with the meconia before wasp pupation. Adults of all three parasitoid species frequently acquired Rickettsia via contact with infected whiteflies, most likely by feeding on the host hemolymph (host feeding, but the rate of infection declined sharply within a few days of wasps being removed from infected whiteflies. In contrast with Rickettsia, Hamiltonella did not establish in any of the parasitoids tested, and none of the parasitoids acquired Hamiltonella by host feeding. This study demonstrates potential routes and barriers to horizontal

  17. Household Transmission of Vibrio cholerae in Bangladesh.

    Directory of Open Access Journals (Sweden)

    Jonathan D Sugimoto

    2014-11-01

    Full Text Available Vibrio cholerae infections cluster in households. This study's objective was to quantify the relative contribution of direct, within-household exposure (for example, via contamination of household food, water, or surfaces to endemic cholera transmission. Quantifying the relative contribution of direct exposure is important for planning effective prevention and control measures.Symptom histories and multiple blood and fecal specimens were prospectively collected from household members of hospital-ascertained cholera cases in Bangladesh from 2001-2006. We estimated the probabilities of cholera transmission through 1 direct exposure within the household and 2 contact with community-based sources of infection. The natural history of cholera infection and covariate effects on transmission were considered. Significant direct transmission (p-value<0.0001 occurred among 1414 members of 364 households. Fecal shedding of O1 El Tor Ogawa was associated with a 4.9% (95% confidence interval: 0.9%-22.8% risk of infection among household contacts through direct exposure during an 11-day infectious period (mean length. The estimated 11-day risk of O1 El Tor Ogawa infection through exposure to community-based sources was 2.5% (0.8%-8.0%. The corresponding estimated risks for O1 El Tor Inaba and O139 infection were 3.7% (0.7%-16.6% and 8.2% (2.1%-27.1% through direct exposure, and 3.4% (1.7%-6.7% and 2.0% (0.5%-7.3% through community-based exposure. Children under 5 years-old were at elevated risk of infection. Limitations of the study may have led to an underestimation of the true risk of cholera infection. For instance, available covariate data may have incompletely characterized levels of pre-existing immunity to cholera infection. Transmission via direct exposure occurring outside of the household was not considered.Direct exposure contributes substantially to endemic transmission of symptomatic cholera in an urban setting. We provide the first estimate of

  18. Stress transmission in soil

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Schjønning, Per

    We urgently need increased quantitative knowledge on stress transmission in real soils loaded with agricultural machinery. 3D measurements of vertical stresses under tracked wheels were performed in situ in a Stagnic Luvisol (clay content 20 %) continuously cropped with small grain cereals......). Seven load cells were inserted horizontally from a pit with minimal disturbance of soil in each of three depths (0.3, 0.6 and 0.9 m), covering the width of the wheeled area. The position of the wheel relative to the transducers was recorded using a laser sensor. Finally, the vertical stresses near...... the soil-tyre interface were measured in separate tests by 17 stress transducers across the width of the tyres. The results showed that the inflation pressure controlled the level of maximum stresses at 0.3 m depth, while the wheel load was correlated to the measured stresses at 0.9 m depth. This supports...

  19. Information transmission strategy

    International Nuclear Information System (INIS)

    Moreau, A.

    1989-01-01

    The four propositions on which our radiation protection information transmission strategy is based are as follows: 1. Emotion exists. It rules our lives at work as well as at home, particularly when radiation safety is involved. Emotion is therefore the terrain for our strategy. 2. The basic emotion is that of fear. This must be recognized and accepted if we want to transmit objective information. The basis of our strategy is therefore listening. 3. A person cannot be divided into parts. The whole person is concerned about safety. We have to deal with that whole person. 4. To follow a strategy we need strategists. We must look at our own emotions and our own motivation before going into the field

  20. Hydatidosis: dynamics of transmission.

    Science.gov (United States)

    Bourée, P

    2001-01-01

    Hydatidosis is a widespread zoonosis infecting a large number of animals and humans. Echinococcus granulosus has the smallest taenia adult of the cestodes but with the largest larva. Its morphologic and biologic features were identified with DNA analysis. Different strains were separated according to the intermediate hosts: sheep, cattle, pigs, horses, camels. Definitive host are canids, mostly dogs, where the worm grows to adulthood in several months. The eggs are scattered in the pasture by wind and water and are ingested by various hosts. The larvae migrate through the intestinal wall and penetrate the organs, mostly liver and lungs. The eggs survive several days outside, depending on the temperature, but numerous eggs die in nature because they cannot resist desiccation and extreme temperatures. Dissemination is accomplished by dogs. In Turkana (Kenya) the incidence of hydatidosis is high because of the close relationship between the population and dogs and the habit of leaving their dead bodies in the grasslands. In rural areas, the custom of slaughtering sheep at home, among the dogs, is an important dissemination factor. The circumstances of transmission vary according to the country. In Europe the natural life cycle of E. granulosus granulosus involves dogs as the definitive host and sheep as the intermediate host. In northern Europe E. granulosus borealis infects the canids and deer. E. granulosus canadensis infects wolves and reindeer, but there are no human cases. In the endemic Mediterranean area, sheep and dromedaries are the intermediate hosts. In South America, the life cycle of E. granulosus develops among several definitive and intermediate hosts. Hence the dynamics of transmission vary according to the countries with different hosts.

  1. Identification of barriers to medication adherence in a Latino population.

    Science.gov (United States)

    Compton, Sheryl; Haack, Sally; Phillips, Charles R

    2010-12-01

    Barriers to medication adherence may present differently in diverse patient populations. Because of changing U.S. demographics, health care providers will be required to identify alternative strategies for managing increasingly diverse patient populations. This pilot project identified barriers that may hinder medication adherence in a Latino population. The results of the survey may identify trends in barriers allowing for the development of interventions aimed at improving medication adherence. The study used a convenience sample of Spanish-labeled prescriptions that had not been picked up from a community pharmacy after a 2-week period to identify study subjects. Patients were contacted by phone and surveyed regarding reasons for not picking up their prescription medication. The 24-item survey instrument consisted of demographic and medication-related questions, reasons for, and associated barriers with failure to pick up medications. The most common classes of medications patients failed to pick up were chronic medications. More than 90% of the patients thought that the medication in question was helpful to them, and nearly 80% thought that the medicine was still needed. Patients cited communication issues (ie, content matter, such as when the prescription was ready), logistics, and limited hours of pharmacy operation as the primary barriers in picking up their medications, whereas nearly 40% failed to identify any barriers. Barriers identified by patients that could be improved included confusion regarding when their prescription was ready and limited hours of pharmacy operation. Most of the patients were comfortable using the American health care system. The barriers to medication adherence identified did not appear to be the result of cultural influences. This could be because the community pharmacy had bilingual staff and interpreters available for patient education and prescription processing. Alternative methods are needed to further identify reasons for

  2. Fusion barrier characteristics of actinides

    Science.gov (United States)

    Manjunatha, H. C.; Sridhar, K. N.

    2018-03-01

    We have studied fusion barrier characteristics of actinide compound nuclei with atomic number range 89 ≤ Z ≤ 103 for all projectile target combinations. After the calculation of fusion barrier heights and positions, we have searched for their parameterization. We have achieved the empirical formula for fusion barrier heights (VB), positions (RB), curvature of the inverted parabola (ħω) of actinide compound nuclei with atomic number range 89 ≤ Z ≤ 103 for all projectile target combinations (6 actinides with the simple inputs of mass number (A) and atomic number (Z) of projectile-targets.

  3. Penetration through the Skin Barrier

    DEFF Research Database (Denmark)

    Nielsen, Jesper Bo; Benfeldt, Eva; Holmgaard, Rikke

    2016-01-01

    -through diffusion cells) as well as in vivo methods (microdialysis and microperfusion). Then follows a discussion with examples of how different characteristics of the skin (age, site and integrity) and of the penetrants (size, solubility, ionization, logPow and vehicles) affect the kinetics of percutaneous......The skin is a strong and flexible organ with barrier properties essential for maintaining homeostasis and thereby human life. Characterizing this barrier is the ability to prevent some chemicals from crossing the barrier while allowing others, including medicinal products, to pass at varying rates...

  4. Vehicle barrier with access delay

    Science.gov (United States)

    Swahlan, David J; Wilke, Jason

    2013-09-03

    An access delay vehicle barrier for stopping unauthorized entry into secure areas by a vehicle ramming attack includes access delay features for preventing and/or delaying an adversary from defeating or compromising the barrier. A horizontally deployed barrier member can include an exterior steel casing, an interior steel reinforcing member and access delay members disposed within the casing and between the casing and the interior reinforcing member. Access delay members can include wooden structural lumber, concrete and/or polymeric members that in combination with the exterior casing and interior reinforcing member act cooperatively to impair an adversarial attach by thermal, mechanical and/or explosive tools.

  5. A LOOK AT CULTURAL BARRIERS

    Directory of Open Access Journals (Sweden)

    Carmen A. VRÂNCEANU

    2015-06-01

    Full Text Available Nowadays the global market allows each individual to work in foreign countries. This fact is a great opportunity for business development, but also puts into light the problem of cultural barriers. Ineffective cross-cultural communication and collaboration can harm employees, customers, and other stakeholders. A company with employees from different cultures must acknowledge and understand these barriers in order to overcome them and to obtain the desired performance. The present study aims to expose the cultural barriers encountered by foreigners in a multinational company from Romania.

  6. Clusters of incompatible genotypes evolve with limited dispersal

    Science.gov (United States)

    Erin L. Landguth; Norman A. Johnson; Samuel A. Cushman

    2015-01-01

    Theoretical and empirical studies have shown heterogeneous selection to be the primary driver for the evolution of reproductively isolated genotypes in the absence of geographic barriers. Here, we ask whether limited dispersal alone can lead to the evolution of reproductively isolated genotypes despite the absence of any geographic barriers or heterogeneous...

  7. 44 CFR 206.344 - Limitations on Federal expenditures.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF HOMELAND SECURITY DISASTER ASSISTANCE FEDERAL DISASTER ASSISTANCE Coastal Barrier Resources Act... within the Coastal Barrier Resources System, including but not limited to: (a) Construction... any project to prevent the erosion of, or to otherwise stabilize, any inlet, shoreline, or inshore...

  8. Autonomous targeting of infectious superspreaders using engineered transmissible therapies.

    Directory of Open Access Journals (Sweden)

    Vincent T Metzger

    2011-03-01

    Full Text Available Infectious disease treatments, both pharmaceutical and vaccine, face three universal challenges: the difficulty of targeting treatments to high-risk 'superspreader' populations who drive the great majority of disease spread, behavioral barriers in the host population (such as poor compliance and risk disinhibition, and the evolution of pathogen resistance. Here, we describe a proposed intervention that would overcome these challenges by capitalizing upon Therapeutic Interfering Particles (TIPs that are engineered to replicate conditionally in the presence of the pathogen and spread between individuals--analogous to 'transmissible immunization' that occurs with live-attenuated vaccines (but without the potential for reversion to virulence. Building on analyses of HIV field data from sub-Saharan Africa, we construct a multi-scale model, beginning at the single-cell level, to predict the effect of TIPs on individual patient viral loads and ultimately population-level disease prevalence. Our results show that a TIP, engineered with properties based on a recent HIV gene-therapy trial, could stably lower HIV/AIDS prevalence by ∼30-fold within 50 years and could complement current therapies. In contrast, optimistic antiretroviral therapy or vaccination campaigns alone could only lower HIV/AIDS prevalence by <2-fold over 50 years. The TIP's efficacy arises from its exploitation of the same risk factors as the pathogen, allowing it to autonomously penetrate superspreader populations, maintain efficacy despite behavioral disinhibition, and limit viral resistance. While demonstrated here for HIV, the TIP concept could apply broadly to many viral infectious diseases and would represent a new paradigm for disease control, away from pathogen eradication but toward robust disease suppression.

  9. Natural and human-induced variability in barrier-island response to sea level rise

    Science.gov (United States)

    Miselis, Jennifer L.; Lorenzo-Trueba, Jorge

    2017-01-01

    Storm-driven sediment fluxes onto and behind barrier islands help coastal barrier systems keep pace with sea level rise (SLR). Understanding what controls cross-shore sediment flux magnitudes is critical for making accurate forecasts of barrier response to increased SLR rates. Here, using an existing morphodynamic model for barrier island evolution, observations are used to constrain model parameters and explore potential variability in future barrier behavior. Using modeled drowning outcomes as a proxy for vulnerability to SLR, 0%, 28%, and 100% of the barrier is vulnerable to SLR rates of 4, 7, and 10 mm/yr, respectively. When only overwash fluxes are increased in the model, drowning vulnerability increases for the same rates of SLR, suggesting that future increases in storminess may increase island vulnerability particularly where sediment resources are limited. Developed sites are more vulnerable to SLR, indicating that anthropogenic changes to overwash fluxes and estuary depths could profoundly affect future barrier response to SLR.

  10. Differences in perceived communication barriers among nurses and elderly patients in China.

    Science.gov (United States)

    Ruan, Jing; Lambert, Vickie A

    2008-06-01

    In China, limited information exists about nurses' and elderly patients' perceptions of barriers to the communication process. Therefore, the purposes of this study were to identify the major communication barriers (nurse-related, patient-related, and environment-related) perceived both by nurses and elderly patients and to determine the perceived differences in the level of importance of the communication barriers between nurses and elderly patients. The sample consisted of 84 nurses and 75 elderly patients who completed a demographic questionnaire and a communication barriers questionnaire. The findings suggested that the nurses and elderly patients often selected similar barriers related to the communication process. The nurses tended to assign higher values to the communication barriers that were found to be significantly different from those of the elderly patients. The study findings provide information about which type of barriers nurses need to address so as to facilitate effective communication with elderly patients.

  11. Natural and Human-Induced Variability in Barrier-Island Response to Sea Level Rise

    Science.gov (United States)

    Miselis, Jennifer L.; Lorenzo-Trueba, Jorge

    2017-12-01

    Storm-driven sediment fluxes onto and behind barrier islands help coastal barrier systems keep pace with sea level rise (SLR). Understanding what controls cross-shore sediment flux magnitudes is critical for making accurate forecasts of barrier response to increased SLR rates. Here, using an existing morphodynamic model for barrier island evolution, observations are used to constrain model parameters and explore potential variability in future barrier behavior. Using modeled drowning outcomes as a proxy for vulnerability to SLR, 0%, 28%, and 100% of the barrier is vulnerable to SLR rates of 4, 7, and 10 mm/yr, respectively. When only overwash fluxes are increased in the model, drowning vulnerability increases for the same rates of SLR, suggesting that future increases in storminess may increase island vulnerability particularly where sediment resources are limited. Developed sites are more vulnerable to SLR, indicating that anthropogenic changes to overwash fluxes and estuary depths could profoundly affect future barrier response to SLR.

  12. Combined DNA extraction and antibody elution from filter papers for the assessment of malaria transmission intensity in epidemiological studies

    NARCIS (Netherlands)

    Baidjoe, A.; Stone, W.; Ploemen, I.; Shagari, S.; Grignard, L.; Osoti, V.; Makori, E.; Stevenson, J.; Kariuki, S.; Sutherland, C.; Sauerwein, R.; Cox, J.; Drakeley, C.; Bousema, T.

    2013-01-01

    BACKGROUND: Informing and evaluating malaria control efforts relies on knowledge of local transmission dynamics. Serological and molecular tools have demonstrated great sensitivity to quantify transmission intensity in low endemic settings where the sensitivity of traditional methods is limited.

  13. Emerging technologies in point-of-care molecular diagnostics for resource-limited settings.

    Science.gov (United States)

    Peeling, Rosanna W; McNerney, Ruth

    2014-06-01

    Emerging molecular technologies to diagnose infectious diseases at the point at which care is delivered have the potential to save many lives in developing countries where access to laboratories is poor. Molecular tests are needed to improve the specificity of syndromic management, monitor progress towards disease elimination and screen for asymptomatic infections with the goal of interrupting disease transmission and preventing long-term sequelae. In simplifying laboratory-based molecular assays for use at point-of-care, there are inevitable compromises between cost, ease of use and test performance. Despite significant technological advances, many challenges remain for the development of molecular diagnostics for resource-limited settings. There needs to be more advocacy for these technologies to be applied to infectious diseases, increased efforts to lower the barriers to market entry through streamlined and harmonized regulatory approaches, faster policy development for adoption of new technologies and novel financing mechanisms to enable countries to scale up implementation.

  14. Time as a trade barrier

    Science.gov (United States)

    2001-07-01

    International trade occurs in physical space and moving goods requires time. This paper examines the importance of time as a trade barrier, estimates the magnitude of time costs, and relates these to patterns of trade and the international organizati...

  15. Coastal Structures and Barriers 2012

    Data.gov (United States)

    California Department of Resources — This dataset is a compilation of the UCSC Sand Retention Structures, MC Barriers, and USACE Coastal Structures. UCSC Sand Retention Structures originate from a...

  16. Coastal Structures and Barriers 2012

    Data.gov (United States)

    California Natural Resource Agency — This dataset is a compilation of the UCSC Sand Retention Structures, MC Barriers, and USACE Coastal Structures. UCSC Sand Retention Structures originate from a...

  17. Low Conductivity Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dong-Ming

    2005-01-01

    Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and requirements will be discussed. An experimental approach is established to monitor in real time the thermal conductivity of the coating systems subjected to high-heat-flux, steady-state and cyclic temperature gradients. Advanced low conductivity thermal barrier coatings have also been developed using a multi-component defect clustering approach, and shown to have improved thermal stability. The durability and erosion resistance of low conductivity thermal barrier coatings have been improved utilizing advanced coating architecture design, composition optimization, in conjunction with more sophisticated modeling and design tools.

  18. Engineered barriers: current status 1989

    International Nuclear Information System (INIS)

    Atkinson, A.; Marsh, G.B.

    1989-06-01

    This report summarises the current state of research relevant to assessing the performance of engineered barriers made of steel and concrete in radioactive waste repositories. The objective of these barriers is to contain substantially the radionuclides within them by providing both physical and chemical impediment to their release. The physical barriers are of most value for highly soluble isotopes with relatively short half-lives (eg 137 Cs), since they can provide a measure of containment until a large fraction of the activity has decayed. In addition they can facilitate retrievability for some period after disposal. The chemical barriers operate by beneficial conditioning of the near field groundwater and providing sites for sorption of radionuclides. Both of these reduce the aqueous concentration of radionuclides in the near field. (author)

  19. Simulation of Series Compensated Transmission Lines Protected with Mov

    OpenAIRE

    Abdolamir Nekoubin

    2011-01-01

    In this paper the behavior of fixed series compensated extra high voltage transmission lines during faults is simulated. Many over-voltage protection schemes for series capacitors are limited in terms of size and performance, and are easily affected by environmental conditions. While the need for more compact and environmentally robust equipment is required. use of series capacitors for compensating part of the inductive reactance of long transmission lines increases the ...

  20. Great Barrier Reef, Queensland, Australia

    Science.gov (United States)

    1990-01-01

    This detailed view of the Great Barrier Reef, Queensland, Australia (19.5S, 149.5E) shows several small patch reefs within the overall reef system. The Great Barrier Reef, largest in the world, comprises thousands of individual reefs of great variety and are closely monitored by marine ecologists. These reefs are about 6000 years old and sit on top of much older reefs. The most rapid coral growth occurs on the landward side of the reefs.

  1. Barriers to Cyber Information Sharing

    Science.gov (United States)

    2014-12-01

    finding out relationships or no relationships. It is more equivalent with this study’s epistemology and methodology than free-mapping or pure...and industry remain educated on and sensitive to methods that can mitigate this concern and ensure antitrust compliance.151 4. Technology...legal scholars. One way to overcome the legal barriers is through education and clarity about the laws that are currently barriers such as anti-trust

  2. Global Health and Emergency Care: Overcoming Clinical Research Barriers.

    Science.gov (United States)

    Levine, Adam C; Barry, Meagan A; Agrawal, Pooja; Duber, Herbert C; Chang, Mary P; Mackey, Joy M; Hansoti, Bhakti

    2017-04-01

    There are many barriers impeding the conduct of high-quality emergency care research, particularly in low- and middle-income countries. Several of these barriers were originally outlined in 2013 as part of the Academic Emergency Medicine Global Health and Emergency Care Consensus Conference. This paper seeks to establish a broader consensus on the barriers to emergency care research globally and proposes a comprehensive array of new recommendations to overcome these barriers. An electronic survey was conducted of a purposive sample of global emergency medicine research experts from around the world to describe the major challenges and solutions to conducting emergency care research in low-resource settings and rank them by importance. The Global Emergency Medicine Think Tank Clinical Research Working Group at the Society for Academic Emergency Medicine 2016 Annual Meeting utilized a modified Delphi technique for consensus-based decision making to categorize and expand upon these barriers and develop a comprehensive array of proposed solutions. The working group identified four broad categories of barriers to conducting emergency care research globally, including 1) the limited availability of research personnel, particularly those with prior research training; 2) logistic barriers and lack of standardization of data collection; 3) ethical barriers to conducting research in resource-limited settings, particularly when no local institutional review board is available; and 4) the relative dearth of funding for global emergency care research. Proposed solutions included building a diverse and interdisciplinary research team structured to promote mentorship of junior researchers, utilizing local research assistants or technologic tools such as telemedicine for language translation, making use of new tools such as mobile health (mHealth) to standardize and streamline data collection, identifying alternatives to local institutional review board approval and the use of

  3. Air barrier systems: Construction applications

    Energy Technology Data Exchange (ETDEWEB)

    Perrault, J.C

    1989-01-01

    An examination is presented of how ordinary building materials can be used in an innovative manner to design, detail, and construct effective air barrier systems for common types of walls. For residential construction, the air drywall approach uses the interior gypsum board as the main component of the wall air barrier system. Joints between the gypsum board and adjacent materials or assemblies are sealed by gaskets. In commercial construction, two different techniques are employed for using gypsum board as air barrier material: the accessible drywall and non-accessible drywall approaches. The former is similar to the air drywall approach except that high performance sealants are used instead of gaskets. In the latter approach, exterior drywall sheathing is the main component of the air barrier system; joints between boards are taped and joints between boards and other components are sealed using elastomeric membrane strips. For various types of commercial and institutional buildings, metal air barrier systems are widely used and include pre-engineered curtain walls or sheet metal walls. Masonry wall systems are regarded as still the most durable, fireproof, and soundproof wall type available but an effective air barrier system has typically been difficult to implement. Factory-made elastomeric membranes offer the potential to provide airtightness to masonry walls. These membranes are applied on the entire masonry wall surface and are used to make airtight connections with other building components. Two types of product are available: thermofusible and peel-and-stick membranes. 5 figs.

  4. Economic alternatives for containment barriers

    International Nuclear Information System (INIS)

    Nicholson, P.J.; Jasperse, B.H.; Fisher, M.J.

    1997-01-01

    Fixation, barriers, and containment of existing landfills and other disposal areas are often performed by insitu auger type soil mixing and jet grouting. Cement or other chemical reagents are mixed with soil to form both vertical and horizontal barriers. Immobilization of contaminants can be economically achieved by mixing soil and the contaminants with reagents that solidify or stabilize the contaminated area. Developed in Japan, and relatively new to the United States, the first large scale application was for a vertical barrier at the Jackson Lake Dam project in 1986. This technology has grown in both the civil and environmental field since. The paper describes current United States practice for Deep Soil Mixing (over 12 meters in depth), and Shallow Soil Mixing for vertical barriers and stabilization/solidification, and Jet Grouting for horizontal and vertical barriers. Creating very low permeability barriers at depth with minimal surface return often makes these techniques economical when compared to slurry trenches. The paper will discuss equipment, materials, soil and strength parameters, and quality control

  5. Photonic limiters with enhanced dynamic range

    Science.gov (United States)

    Kononchuk, Rodion; Limberopoulos, Nicholaos; Anisimov, Igor; Vitebskiy, Ilya; Chabanov, Andrey

    2018-02-01

    Optical limiters transmit low intensity input light while blocking input light with the intensity exceeding certain limiting threshold. Conventional passive limiters utilize nonlinear optical materials, which are transparent at low light intensity and turn absorptive at high intensity. Strong nonlinear absorption, though, can result in over- heating and destruction of the limiter. Another problem is that the limiting threshold provided by the available optical material with nonlinear absorption is too high for many applications. To address the above problems, the nonlinear material can be incorporated in a photonic structure with engineered dispersion. At low intensity, the photonic structure can display resonant transmission via localized mode(s), while at high intensity the resonant transmission can disappear, and the entire stack can become highly re ective (not absorptive) within a broad frequency range. In the proposed design, the transition from the resonant transmission at low intensity to nearly total re ectivity at high intensity does not rely on nonlinear absorption; instead, it requires only a modest change in the refractive index of the nonlinear material. The latter implies a dramatic increase in the dynamic range of the limiter. The main idea is to eliminate the high-intensity resonant transmission by decoupling the localized (resonant) modes from the input light, rather than suppressing those modes using nonlinear absorption. Similar approach can be used for light modulation and switching.

  6. Human-to-human transmission of Brucella - a systematic review.

    Science.gov (United States)

    Tuon, Felipe F; Gondolfo, Regina B; Cerchiari, Natacha

    2017-05-01

    The most common form of transmitting human brucellosis is through contaminated food or direct contact with infected animals. Human-to-human transmission (HHT) has been described as isolated case reports. The aim of this systematic review was to describe all cases of HHT of human brucellosis reported in the medical literature. A literature search was conducted using PubMed, Scopus and Scielo databases using specific search terms published until March 2016. Two investigators independently determined study eligibility. All clinical data were evaluated to construct a table comprising the most important clinical aspects, age, gender, confirmed infection and detection method, transmission method and HHT confirmation and potential source of infection for human transmission. No statistical method was employed in this study. The initial search resulted in 615 publications, but only 35 were included. 45 brucellosis HHT cases were identified. 61% of patients who acquired brucellosis from another human were <1 year old (newborn and breastfeeding). Other cases include sexual transmission, blood transfusion, bone marrow transplantation and aerosol from an infected patient. Most patients (40/45) presented symptoms upon diagnosis. Diagnostic tests included culture, molecular methods and serum testing. Human brucellosis is a disease liable to transmission between humans by placental barrier, lactation, sexual and tissues such as blood and bone marrow. The indication for screening in tissue banks, transplants, blood and pregnancy is not yet established. © 2017 John Wiley & Sons Ltd.

  7. Composite Based EHV AC Overhead Transmission Lines

    DEFF Research Database (Denmark)

    Sørensen, Thomas Kjærsgaard

    ) levels are still not seen as possibility, the future expansion of transmission grids are dependent on new solutions with lessened environment impact, especially with regard to the visual impact. In the present Thesis, composite materials and composite based overhead line components are presented...... and analysed with regard to the possibilities, limitations and risks widespread application of composite materials on EHV AC overhead transmission lines may present. To form the basis for evaluation of the useability of composite materials, dierent overhead line projects aimed at reducing the environmental...... impact are analysed with regard to their visual impact reducing design steps. These are used to form the basis for overhead line system design ideas, which are analysed with regard to application of composite materials and components. Composite materials and components, when applied in EHV systems...

  8. Barriers and attitudes towards hIV Voluntary counselling and Testing ...

    African Journals Online (AJOL)

    Official Publication of the Tanzania Medical Students' Association. 20. Barriers and attitudes towards hIV ... risk reduction in certain groups, behaviour change and reduced transmission2. Young people are the ... Of those who ever used VCT services 32.7% were just interested in knowing their HIV status and to get HIV ...

  9. Reduction of sound transmission through fuselage walls by alternate resonance tuning (A.R.T.)

    Science.gov (United States)

    Bliss, Donald B.; Gottwald, James A.

    1989-01-01

    The ability of alternate resonance tuning (ART) to block sound transmission through light-weight flexible paneled walls by controlling the dynamics of the wall panels is considered. Analytical results for sound transmission through an idealized panel wall illustrate the effect of varying system parameters and show that one or more harmonics of the incident sound field can be cancelled by the present method. Experimental results demonstrate that very large transmission losses with reasonable bandwidths can be achieved by a simple ART panel barrier in a duct.

  10. Horizontal versus familial transmission of Helicobacter pylori.

    Directory of Open Access Journals (Sweden)

    Sandra Schwarz

    2008-10-01

    transmission that is typical of developed countries. Predominantly familial transmission in urban societies is likely a result of modern living conditions with good sanitation and where physical contact between persons outside the core family is limited and regulated by societal rules. The patterns observed in rural South African families may be representative of large parts of the developing world.

  11. On the repair of the dentine barrier.

    Science.gov (United States)

    Fransson, Helena

    2012-01-01

    The overall aim of this thesis was to study some aspects of the repair of the dentine barrier, especially in conjunction with dental pulp capping. Understanding the events leading to the healing of the dentine and pulp, and hence successfully preserving the vitality and functions of the tooth, would lead to a scientific basis for a less invasive treatment of pulp exposures than performing root canal treatments. The surfaces of the body have physiological barrier functions aimed at protecting the body from external noxious agents. In the tooth, the odontoblasts, which line the outermost part of the pulp and are responsible for the formation of dentine, play a central role in the barrier function and thus in the defence mechanisms of the tooth. The micro-organisms in the caries lesion can reach the pulp via the dentinal tubules. However, the barrier function helps to prevent microbial invasion and thereby avoid deleterious inflammation and subsequent necrosis of the pulp. Dentine repair is an important part of the barrier function. There are however doubts as to whether the repair also leads to restitution of the function and the ability to withstand bacterial influx over the longer term. Pulp capping is a treatment method used when the pulp has been exposed in order to stimulate healing of the pulp and dentine. The evidence for repair of the dentine after pulp capping in humans has been studied by means of a systematic review. The focus of the literature search was studies performed in humans where hard tissue formation had been studied with the aid of a microscope. We concluded, based on the limited evidence available, that calcium hydroxide based materials but not bonding agents promote formation of a hard tissue bridge. Scientific evidence was lacking as to whether MTA was better than calcium hydroxide based materials in this regard. A gel (Emdogain Gel) containing amelogenin, known to be involved in dentinogenesis, was evaluated with regard to formation of hard

  12. Qualitative motivators and barriers to pandemic vs. seasonal influenza vaccination among healthcare workers: a content analysis.

    Science.gov (United States)

    Prematunge, Chatura; Corace, Kimberly; McCarthy, Anne; Nair, Rama C; Roth, Virginia; Suh, Kathryn N; Garber, Gary

    2014-12-12

    Influenza is a major concern across healthcare environments. Annual vaccination of healthcare workers (HCW) remains a key mode of influenza prevention in healthcare settings. Yet influenza vaccine coverage among HCWs continues to be below recommended targets, in pandemic and non-pandemic settings. Thus, the primary objective of this analysis is to identify motivators and barriers to pandemic (panINFLU) and seasonal influenza vaccination (sINFLU) through the qualitative analysis of HCW provided reasons driving HCW's personal vaccination decisions. Data were collected from a multi-professional sample of HCWs via a cross-sectional survey study, conducted at a tertiary-care hospital in Ontario, Canada. HCW provided and ranked qualitative reasons for personal (1) panINFLU (pH1N1) and (2) sINFLU (2008/2009 season) vaccine uptake and avoidance were used to identify key vaccination motivators and barriers through content analysis methodology. Most HCW vaccination motivators and barriers were found to be similar for panINFLU and sINFLU vaccines. Personal motivators had the greatest impact on vaccination (panINFLU 29.9% and sINFLU 33.9%). Other motivators included preventing influenza in loved ones, patients, and community, and awareness of HCW role in influenza transmission. In contrast, concerns of vaccine safety and limited HCW knowledge of influenza vaccines (panINFLU 46.2% and sINFLU 37.3%). HCW vaccination during the pandemic was motivated by panINFLU related fear, epidemiology, and workplace pro-vaccination policies. HCW perceptions of accelerated panINFLU vaccine development and vaccine safety compromises, negative views of external sources (i.e. media, pharmaceutical companies, and regulatory agencies) and pandemic management strategies were barriers specific to panINFLU vaccine. HCW panINFLU and sINFLU vaccine coverage can increase if future vaccination programs (1) highlight personal vaccination benefits (2) emphasize the impact HCW non-vaccination on family

  13. Influence of solid noise barriers on near-road and on-road air quality

    Science.gov (United States)

    Baldauf, Richard W.; Isakov, Vlad; Deshmukh, Parikshit; Venkatram, Akula; Yang, Bo; Zhang, K. Max

    2016-03-01

    Public health concerns regarding adverse health effects for populations spending significant amounts of time near high traffic roadways has increased substantially in recent years. Roadside features, including solid noise barriers, have been investigated as potential methods that can be implemented in a relatively short time period to reduce air pollution exposures from nearby traffic. A field study was conducted to determine the influence of noise barriers on both on-road and downwind pollutant concentrations near a large highway in Phoenix, Arizona, USA. Concentrations of nitrogen dioxide, carbon monoxide, ultrafine particles, and black carbon were measured using a mobile platform and fixed sites along two limited-access stretches of highway that contained a section of noise barrier and a section with no noise barrier at-grade with the surrounding terrain. Results of the study showed that pollutant concentrations behind the roadside barriers were significantly lower relative to those measured in the absence of barriers. The reductions ranged from 50% within 50 m from the barrier to about 30% as far as 300 m from the barrier. Reductions in pollutant concentrations generally began within the first 50 m of the barrier edge; however, concentrations were highly variable due to vehicle activity behind the barrier and along nearby urban arterial roadways. The concentrations on the highway, upwind of the barrier, varied depending on wind direction. Overall, the on-road concentrations in front of the noise barrier were similar to those measured in the absence of the barrier, contradicting previous modeling results that suggested roadside barriers increase pollutant levels on the road. Thus, this study suggests that noise barriers do reduce potential pollutant exposures for populations downwind of the road, and do not likely increase exposures to traffic-related pollutants for vehicle passengers on the highway.

  14. Endoscopic transmission of Helicobacter pylori

    NARCIS (Netherlands)

    Tytgat, G. N.

    1995-01-01

    The contamination of endoscopes and biopsy forceps with Helicobacter pylori occurs readily after endoscopic examination of H. pylori-positive patients. Unequivocal proof of iatrogenic transmission of the organism has been provided. Estimates for transmission frequency approximate to 4 per 1000

  15. HVDC power transmission technology assessment

    Energy Technology Data Exchange (ETDEWEB)

    Hauth, R.L.; Tatro, P.J.; Railing, B.D. [New England Power Service Co., Westborough, MA (United States); Johnson, B.K.; Stewart, J.R. [Power Technologies, Inc., Schenectady, NY (United States); Fink, J.L.

    1997-04-01

    The purpose of this study was to develop an assessment of the national utility system`s needs for electric transmission during the period 1995-2020 that could be met by future reduced-cost HVDC systems. The assessment was to include an economic evaluation of HVDC as a means for meeting those needs as well as a comparison with competing technologies such as ac transmission with and without Flexible AC Transmission System (FACTS) controllers. The role of force commutated dc converters was to be assumed where appropriate. The assessment begins by identifying the general needs for transmission in the U.S. in the context of a future deregulated power industry. The possible roles for direct current transmission are then postulated in terms of representative scenarios. A few of the scenarios are illustrated with the help of actual U.S. system examples. non-traditional applications as well as traditional applications such as long lines and asynchronous interconnections are discussed. The classical ``break-even distance`` concept for comparing HVDC and ac lines is used to assess the selected scenarios. The impact of reduced-cost converters is reflected in terms of the break-even distance. This report presents a comprehensive review of the functional benefits of HVDC transmission and updated cost data for both ac and dc system components. It also provides some provocative thoughts on how direct current transmission might be applied to better utilize and expand our nation`s increasingly stressed transmission assets.

  16. Perceived barriers to the implementation of Isoniazid preventive ...

    African Journals Online (AJOL)

    Perceived barriers to the implementation of Isoniazid preventive therapy for people living with HIV in resource constrained settings: a qualitative study. ... weak patient/healthcare provider relationship due to limited quality interaction; lack of patient information, patient empowerment and proper counseling on IPT; and the ...

  17. Possible barriers to the advancement of women to leadership ...

    African Journals Online (AJOL)

    In a previous article we discussed, in detail, the problem of this study, its aim, methods used, its limitations, and the first five of twelve barriers that were perceived to be obstacles to the advancement of women to leadership positions in the education profession, in particular, and the workplace, in general. To avoid repetition ...

  18. A New Measure of Home Exercise Benefits and Barriers

    Science.gov (United States)

    Thind, Herpreet; Fava, Joseph; Traficante, Regina; Bock, Beth C.

    2016-01-01

    Background: To increase physical activity among college students, new approaches are needed including the exploration of home-based exercise. However, research related to potential facilitators and barriers to exercising at home is limited. Purpose: The goal of this study was to develop a reliable and valid measure that can assess predictors of…

  19. Barriers to International Student Mobility: Evidence from the Erasmus Program

    Science.gov (United States)

    Souto-Otero, Manuel; Huisman, Jeroen; Beerkens, Maarja; de Wit, Hans; Vujic, Suncica

    2013-01-01

    In this article, we look at the barriers to international student mobility, with particular reference to the European Erasmus program. Much is known about factors that support or limit student mobility, but very few studies have made comparisons between participants and nonparticipants. Making use of a large data set on Erasmus and non-Erasmus…

  20. Barriers to implement green supply chain management in automobile industry using interpretive structural modeling technique: An Indian perspective

    Directory of Open Access Journals (Sweden)

    Sunil Luthra

    2011-07-01

    Full Text Available Purpose: Green Supply Chain Management (GSCM has received growing attention in the last few years. Most of the automobile industries are setting up their own manufacturing plants in competitive Indian market. Due to public awareness, economic, environmental or legislative reasons, the requirement of GSCM has increased.  In this context, this study aims to develop a structural model of the barriers to implement GSCM in Indian automobile industry.Design/methodology/approach: We have identified various barriers and contextual relationships among the identified barriers. Classification of barriers has been carried out based upon dependence and driving power with the help of MICMAC analysis. In addition to this, a structural model of barriers to implement GSCM in Indian automobile industry has also been put forward using Interpretive Structural Modeling (ISM technique. Findings: Eleven numbers of relevant barriers have been identified from literature and subsequent discussions with experts from academia and industry. Out of which, five numbers of barriers have been identified as dependent variables; three number of barriers have been identified as the driver variables and three number of barriers have been identified as the linkage variables. No barrier has been identified as autonomous variable. Four barriers have been identified as top level barriers and one bottom level barrier. Removal of these barriers has also been discussed.Research limitations/implications: A hypothetical model of these barriers has been developed based upon experts’ opinions. The conclusions so drawn may be further modified to apply in real situation problem. Practical implications: Clear understanding of these barriers will help organizations to prioritize better and manage their resources in an efficient and effective way.Originality/value: Through this paper we contribute to identify the barriers to implement GSCM in Indian automobile industry and to prioritize them

  1. Transformer coupling for transmitting direct current through a barrier

    Science.gov (United States)

    Brown, R.L.; Guilford, R.P.; Stichman, J.H.

    1987-06-29

    The transmission system for transmitting direct current from an energy source on one side of an electrical and mechanical barrier to a load on the other side of the barrier utilizes a transformer comprising a primary core on one side of the transformer and a secondary core on the other side of the transformer. The cores are magnetically coupled selectively by moving a magnetic ferrite coupler in and out of alignment with the poles of the cores. The direct current from the energy source is converted to a time varying current by an oscillating circuit, which oscillating circuit is optically coupled to a secondary winding on the secondary core to interrupt oscillations upon the voltage in the secondary winding exceeding a preselected level. 4 figs.

  2. Comments on ''single-barrier penetration of electrons''

    International Nuclear Information System (INIS)

    Karlsson, F.; Froeman, P.O.

    1980-01-01

    It is pointed out that the problem treated in a recent paper by Shaw, Measure, Wald and Lu, concerning single-barrier penetration of electrons, has already been solved in a simpler and more general way. In fact, simple, explicit formulae for the solution of the single-barrier transmission problem by means of phase-integral approximations of arbitrary order exist since several years. By numerical evaluation of these formulae on a small desk calculator, one can easily obtain results which, in the two lowest orders of approximation, agree with those given by Shaw, Measure, Wald and Lu, and in higher orders are more accurate, if the energy of the particle is not too low. This assertion is also illustrated numerically. (author)

  3. Fundamental Investigations Regarding Barrier Properties of Grafted PVOH Layers

    Directory of Open Access Journals (Sweden)

    Markus Schmid

    2012-01-01

    Full Text Available The current work focuses on fundamental investigations regarding the barrier properties of grafted PVOH layers produced by the Transfer Method. The layers (or papers used for the different experiments were produced and grafted during the course of this work. Papers with different types of PVOH (different Mowiol types were produced by coating. Experiments using different parameters (temperature, reaction duration, and concentration were performed using the Transfer Method. Contact angle measurements and Cobb60 measurements were carried out on the grafted and untreated PVOH layers. Furthermore, the water vapour transmission rate of the PVOH layers was determined. The results of this work showed that the method of chromatogeny or chromatogenic chemistry improves the water vapour barrier properties of grafted PVOH layers enormously.

  4. Performance of engineered barriers for low-level waste

    International Nuclear Information System (INIS)

    Taplin, D.; Claridge, F.B.

    1987-09-01

    Geotechnical Resources Ltd., in association with Komex Consultants Ltd., was retained to collect, synthesize and evaluate the available information on the long term performance of engineered barriers for low-level radioactive wastes disposed in Canada. Literature was researched from Canadian, United States and European sources. A variety of barrier materials were assessed in the study and included natural clays, concrete and cement, metals, bentonite-sand admixes, bitumen and bituminous admixes, soil cement and polymeric membranes. The generalized geological and geotechnical conditions encountered within the soil and rock host media currently under consideration for disposal sites in southern Ontario were also summarized. Both internal barriers, or buffers, to immobilize the waste material and reduce radionuclide mobility, as well as external barriers to limit the migration of contaminants were examined. Microbial activities within the waste forms were analyzed, including cellulose degradation, methanogenesis and bicarbonate and organic reactions. Microbial interactions with the various engineered barrier materials under consideration were also assessed. Finally, the anticipated long term performances of the respective barrier materials under consideration were evaluated, along with the general suitability of the geological host media being proposed for disposal sites

  5. Characterization of founder viruses in very early SIV rectal transmission.

    Science.gov (United States)

    Yuan, Zhe; Ma, Fangrui; Demers, Andrew J; Wang, Dong; Xu, Jianqing; Lewis, Mark G; Li, Qingsheng

    2017-02-01

    A better understanding of HIV-1 transmission is critical for developing preventative strategies. To that end, we analyzed 524 full-length env sequences of SIVmac251 at 6 and 10 days post intrarectal infection of rhesus macaques. There was no tissue compartmentalization of founder viruses across plasma, rectal and distal lymphatic tissues for most animals; however one animal has evidence of virus tissue compartmentalization. Despite identical viral inoculums, founder viruses were animal-specific, primarily derived from rare variants in the inoculum, and have a founder virus signature that can distinguish dominant founder variants from minor founder or untransmitted variants in the inoculum. Importantly, the sequences of post-transmission defective viruses were phylogenetically associated with competent viral variants in the inoculum and were mainly converted from competent viral variants by frameshift rather than APOBEC mediated mutations, suggesting the converting the transmitted viruses into defective viruses through frameshift mutation is an important component of rectal transmission bottleneck. Anorectal receptive intercourse is a common route of HIV-1 transmission and a better understanding of the transmission mechanisms is critical for developing HIV-1 preventative strategies. Here, we report that there is no tissue compartmentalization of founder viruses during very early rectal transmission of SIV in the majority of rhesus macaques and founder viruses are preferentially derived from rare variant in the inoculum. We also found that founder viruses are animal-specific despite identical viral inoculums. After viruses cross the mucosal barriers, the host further reduces viral diversity by converting some of the transmitted functional viruses into defective viruses through frameshift rather than APOBEC derived mutations. To our knowledge, this is the first study of founder viruses at multiple tissue sites during very early rectal transmission. Copyright © 2016

  6. A Transmission-Cost-Based Model to Estimate the Amount of Market-Integrable Wind Resources

    DEFF Research Database (Denmark)

    Morales González, Juan Miguel; Pinson, Pierre; Madsen, Henrik

    2012-01-01

    -cost perspective. This model accounts for the uncertain character of wind by using a modeling framework based on stochastic optimization, simulates market barriers by means of a bi-level structure, and considers the financial risk of investments in transmission through the conditional value-at-risk. The major...

  7. 78 FR 44900 - Communication of Operational Information Between Natural Gas Pipelines and Electric Transmission...

    Science.gov (United States)

    2013-07-25

    ... transmission operators and interstate natural gas pipelines. The Commission intends to remove any barriers to...-17-000] Communication of Operational Information Between Natural Gas Pipelines and Electric... the Commission's regulations to provide explicit authority to interstate natural gas pipelines and...

  8. Navigating language barriers under difficult circumstances.

    Science.gov (United States)

    Schenker, Yael; Lo, Bernard; Ettinger, Katharine M; Fernandez, Alicia

    2008-08-19

    The proportion of the U.S. population with limited English proficiency is growing. Physicians often find themselves caring for patients with limited English proficiency in settings with limited language services. There has been little exploration of the decisions physicians face when providing care across language barriers. The authors offer a conceptual framework to aid physicians in thinking through difficult choices about language services and provide responses to common questions encountered in the care of patients with limited English proficiency. Specifically, they describe 4 factors that should inform the decision to call an interpreter (the clinical situation, degree of language gap, available resources, and patient preference), discuss who may be an appropriate interpreter, and offer strategies for when a professional interpreter is not available. The authors use a hypothetical case to illustrate how decisions about language services may evolve over the course of an interaction. This conceptual and practical approach can help clinicians to improve the quality of care provided to patients with limited English proficiency.

  9. Comprehensive investigation of the angular transmission in magnetic spectrometers

    CERN Document Server

    Pereira-Conca, J; Schmidt, K H

    2003-01-01

    Magnetic spectrometers are largely used in experimental nuclear physics. These devices allow one to perform precise measurements of the reaction kinematics or to separate and fully identify the reaction residues for nuclear-dynamics and structure studies. They can also be used as separators to produce radioactive nuclear beams. However, all these applications are affected by the limited transmission of the reaction residues through the spectrometer. The final transmission depends on the ion-optical characteristics and the mechanical constraints of the spectrometer but also on the kinematic properties of the considered nuclei. The ion optics are characterised by the bending and focusing powers of the magnetic elements which constitute the spectrometer. The reaction mechanism determines the kinematics of the particles. The transmission losses in any magnetic spectrometer can be attributed to its limited acceptance in longitudinal momentum and angle. The limitation in longitudinal momentum can be overcome by com...

  10. Roll-to-roll vacuum deposition of barrier coatings

    CERN Document Server

    Bishop, Charles A

    2015-01-01

    It is intended that the book will be a practical guide to provide any reader with the basic information to help them understand what is necessary in order to produce a good barrier coated web or to improve the quality of any existing barrier product. After providing an introduction, where the terminology is outlined and some of the science is given (keeping the mathematics to a minimum), including barrier testing methods, the vacuum deposition process will be described. In theory a thin layer of metal or glass-like material should be enough to convert any polymer film into a perfect barrier material. The reality is that all barrier coatings have their performance limited by the defects in the coating. This book looks at the whole process from the source materials through to the post deposition handling of the coated material. This holistic view of the vacuum coating process provides a description of the common sources of defects and includes the possible methods of limiting the defects. This enables readers...

  11. Barriers to Diagnosis Access for Chagas Disease in Colombia.

    Science.gov (United States)

    Olivera, Mario Javier; Porras Villamil, Julián Felipe; Toquica Gahona, Christian Camilo; Rodríguez Hernández, Jorge Martín

    2018-01-01

    Chagas disease is the leading cause of nonischemic cardiomyopathy in Latin America. Timely access to diagnosis and trypanocidal treatment and preventive tools for millions of infected people continues to be a challenge. The purpose of this study was to identify potential barriers for the diagnosis of Chagas disease in Colombia from the perspective of healthcare providers. Using a simultaneous mixed-methods study design, we analyzed trends in access to screening and diagnosis for Chagas disease in Colombia and assessed the national barriers to access. The main barriers to access at the national level included a limited governmental public health infrastructure for the diagnosis of Chagas disease and limited physician awareness and knowledge of the disease. Data indicate that 1.5% of total expected cases based on national prevalence estimates were reported. Few public health laboratories have the capacity to perform complementary tests for the diagnosis of Chagas disease and almost 6 months elapse between the requests of the tests and the confirmation of the disease. This study shows that infected people must overcome a number of barriers to achieve diagnosis. Reducing barriers to early diagnosis of Chagas disease is an important goal in the fight against the disease.

  12. PERFORMANCE EVALUATION OF LOCAL BARRIER COVERAGE IN WIRELESS SENSOR NETWORKS

    OpenAIRE

    K. K. Kannan

    2017-01-01

    The main aim of project is to create appropriate model of coverage for movement detection applications such as intrusion detection. However it has been proved that given sensor deployment sensors cannot locally determine whether deployment provides global coverage. Making it impossible to develop localized algorithms thus limiting it Dees use in practice. In this project I am introducing the concept of local barrier coverage to address this limitation. It is motivated by the observation that ...

  13. Evaluation of diffusion barrier and electrical properties of tantalum oxynitride thin films for silver metallization

    International Nuclear Information System (INIS)

    Misra, E.; Wang, Y.; Theodore, N.D.; Alford, T.L.

    2004-01-01

    The thermal stability and the diffusion barrier properties of DC reactively sputtered tantalum oxynitride (Ta-O-N) thin films, between silver (Ag) and silicon (Si) p + n diodes were investigated. Both materials characterization (X-ray diffraction analysis, Rutherford backscattering spectrometry (RBS), Auger depth profiling) and electrical measurements (reverse-biased junction leakage current-density) were used to evaluate diffusion barrier properties of the thin films. The leakage current density of p + n diodes with the barrier (Ta-O-N) was approximately four orders of magnitude lower than those without barriers after a 30 min, 400 deg. C back contact anneal. The Ta-O-N barriers were stable up to 500 deg. C, 30 min anneals. However, this was not the case for the 600 deg. C anneal. RBS spectra and cross-sectional transmission electron microscopy of as-deposited and vacuum annealed samples of Ag/barrier (Ta-O-N)/Si indicate the absence of any interfacial interaction between the barrier and substrate (silicon). The failure of the Ta-O-N barriers has been attributed to thermally induced stresses, which cause the thin film to crack at elevated temperatures

  14. Measurements of tunneling barrier thicknesses for Nb/Al–AlOx/Nb tunnel junctions

    International Nuclear Information System (INIS)

    Kang, Xinjie; Ying, Liliang; Wang, Hai; Zhang, Guofeng; Peng, Wei; Kong, Xiangyan; Xie, Xiaoming; Wang, Zhen

    2014-01-01

    Highlights: • We estimate the average barrier height (Φ) of Nb/Al–AlO x /Nb tunnel junctions. • Dependence of the AlOx thickness (dAlOx) on O 2 exposure was described. • The thicknesses of AlOx barriers were measured using transmission electron microscopy (TEM). • X-ray Reflection (XRR) measurements and simulations were used to verify the AlOx thickness. - Abstract: The tunnel barrier thicknesses of Nb/Al–AlO x /Nb tunnel junctions were measured using transmission electron microscopy (TEM) and X-ray Reflection (XRR). By investigating the barrier thickness dependence of current density J c , the barrier height for Nb/Al–AlO x /Nb junctions was calculated. Nb/Al–AlO x /Nb junctions with different J c were fabricated by controlling the O 2 exposure in Al oxidation. The junctions show good tunneling properties with subgap leakage factor V m larger than 30 mV in the range of J c from tens of A/cm 2 to several kA/cm 2 . TEM images showed clear interface and indicated the AlO x thicknesses ranging from 0.8 nm to 1.9 nm, and the average barrier height was estimated to be 0.17 eV for Nb/Al–AlO x /Nb tunnel junctions

  15. Diabetes and diet : managing dietary barriers

    NARCIS (Netherlands)

    Friele, R.D.

    1989-01-01

    This thesis reports on the barriers diabetic patients experience with their diet, and the ways they cope with these barriers. A dietary barrier is a hinderance to a person's well-being, induced by being advised a diet. First inventories were made of possible dietary barriers and ways of

  16. Glial diffusion barriers during aging and pathological states

    Czech Academy of Sciences Publication Activity Database

    Syková, Eva

    2001-01-01

    Roč. 132, - (2001), s. 339-363 ISSN 0079-6123 R&D Projects: GA MŠk VS96130; GA ČR GV307/96/K226; GA ČR GV309/97/K048; GA ČR GA309/99/0657; GA ČR GA305/99/0655; GA ČR GA309/00/1430 Institutional research plan: CEZ:AV0Z5039906 Keywords : diffusion barriers volume transmission Subject RIV: FH - Neurology Impact factor: 1.409, year: 2001

  17. Complementary Barrier Infrared Detector (CBIRD) with Double Tunnel Junction Contact and Quantum Dot Barrier Infrared Detector (QD-BIRD)

    Science.gov (United States)

    Ting, David Z.-Y; Soibel, Alexander; Khoshakhlagh, Arezou; Keo, Sam A.; Nguyen, Jean; Hoglund, Linda; Mumolo, Jason M.; Liu, John K.; Rafol, Sir B.; Hill, Cory J.; hide

    2012-01-01

    The InAs/GaSb type-II superlattice based complementary barrier infrared detector (CBIRD) has already demonstrated very good performance in long-wavelength infrared (LWIR) detection. In this work, we describe results on a modified CBIRD device that incorporates a double tunnel junction contact designed for robust device and focal plane array processing. The new device also exhibited reduced turn-on voltage. We also report results on the quantum dot barrier infrared detector (QD-BIRD). By incorporating self-assembled InSb quantum dots into the InAsSb absorber of the standard nBn detector structure, the QD-BIRD extend the detector cutoff wavelength from approximately 4.2 micrometers to 6 micrometers, allowing the coverage of the mid-wavelength infrared (MWIR) transmission window. The device has been observed to show infrared response at 225 K.

  18. Implementation of renewable technologies - Opportunities and barriers. Zimbabwe country study

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    . The committee was tasked with the responsibility of coming up with recommendations to barrier removal and promotion of RETs. After interested stake holders had presented their candidate projects proposals, the committee started the process of identifying barriers to the projects and selecting feasible projects. A final workshop was then held in August 2000 where the findings of the whole process were presented to all stake holders for discussion and analysis. The problem of barriers was found to be very complex. A good number of RETs projects in the country were successfully implemented. The success of such projects was underpinned by the following factors, addressing the immediate and basic needs of the people, participatory approach, awareness creation and enabling income generation activities. Some projects were also not very successful as they faced a lot of barriers like poor institutional framework, limited financial resources, lack of appreciation of associated benefits and technology failure. A close analysis of barriers revealed that there are two classes of barrier namely primary barriers and secondary barriers. Primary barriers are the real barriers while secondary barriers are more of the effects of primary barriers. (BA)

  19. Reactive barriers for 137Cs retention

    International Nuclear Information System (INIS)

    Krumhansl, James L.; Brady, Patrick V.; Anderson, Howard L.

    2000-01-01

    137 Cs was dispersed globally by cold war activities and, more recently, by the Chernobyl accident. Engineered extraction of 137 Cs from soils and groundwaters is exceedingly difficult. Because the half life of 137 Cs is only 30.2 years, remediation might be more effective (and less costly) if 137 Cs bioavailability could be demonstrably limited for even a few decades by use of a reactive barrier. Essentially permanent isolation must be demonstrated in those few settings where high nuclear level wastes contaminated the environment with 135 Cs (half life 2.3x10 6 years) in addition to 137 Cs. Clays are potentially a low-cost barrier to Cs movement, though their long-term effectiveness remains untested. To identify optimal clays for Cs retention Cs resorption was measured for five common clays: Wyoming Montmorillonite (SWy-1), Georgia Kaolinites (KGa-1 and KGa-2), Fithian Illite (F-Ill), and K-Metabentonite (K-Mbt). Exchange sites were pre-saturated with 0.16 M CsCl for 14 days and readily exchangeable Cs was removed by a series of LiNO 3 and LiCl washes. Washed clay were then placed into dialysis bags and the Cs release to the deionized water outside the bags measured. Release rates from 75 to 139 days for SWy-1, K-Mbt and F- 111 were similar; 0.017 to 0.021% sorbed Cs released per day. Both kaolinites released Cs more rapidly (0.12 to 0.05% of the sorbed Cs per day). In a second set of experiments, clays were doped for 110 days and subjected to an extreme and prolonged rinsing process. All the clays exhibited some capacity for irreversible Cs uptake so most soils have some limited ability to act as a natural barrier to Cs migration. However, the residual loading was greatest on K-Mbt (∼ 0.33 wt% Cs). Thus, this clay would be the optimal material for constructing artificial reactive barriers

  20. Strategies Used by Prehospital Providers to Overcome Language Barriers.

    Science.gov (United States)

    Tate, Ramsey C; Hodkinson, Peter W; Meehan-Coussee, Kelly; Cooperstein, Noah

    2016-01-01

    Language barriers are commonly encountered in the prehospital setting but there is a paucity of research on how prehospital providers address language discordance. We sought to identify the communication strategies, and the limitations of those strategies, used by emergency medical services (EMS) providers when confronted with language barriers in a variety of linguistic and cultural contexts. EMS providers were queried regarding communication strategies to overcome language barriers as part of an international, multi-site, sequential explanatory, qualitative-predominant, mixed methods study of prehospital language barriers. A survey of EMS telecommunicators was administered at dispatch centers in New Mexico (United States) and Western Cape (South Africa). Semi-structured qualitative interviews of EMS field providers were conducted at agencies who respond to calls from participating dispatch centers. Survey data included quantitative data on demographics and communication strategies used to overcome language barriers as well as qualitative free-text responses on the limitations of strategies. Interviews elicited narratives of encounters with language-discordant patients and the strategies used to communicate. Data from the surveys and interviews were integrated at the point of analysis. 125 telecommunicators (overall response rate of 84.5%) and a purposive sample of 27 field providers participated in the study. The characteristics of participants varied between countries and between agencies, consistent with variations in participating agencies' hiring and training practices. Telecommunicators identified 3rd-party telephonic interpreter services as the single most effective strategy when available, but also described time delays and frustration with interpreter communications that leads them to preferentially try other strategies. In the field, all providers reported using similar strategies, relying heavily on bystanders, multilingual coworkers, and non

  1. The evolution of transmission mode

    Science.gov (United States)

    Forbes, Mark R.; Hauffe, Heidi C.; Kallio, Eva R.; Okamura, Beth; Sait, Steven M.

    2017-01-01

    This article reviews research on the evolutionary mechanisms leading to different transmission modes. Such modes are often under genetic control of the host or the pathogen, and often in conflict with each other via trade-offs. Transmission modes may vary among pathogen strains and among host populations. Evolutionary changes in transmission mode have been inferred through experimental and phylogenetic studies, including changes in transmission associated with host shifts and with evolution of the unusually complex life cycles of many parasites. Understanding the forces that determine the evolution of particular transmission modes presents a fascinating medley of problems for which there is a lack of good data and often a lack of conceptual understanding or appropriate methodologies. Our best information comes from studies that have been focused on the vertical versus horizontal transmission dichotomy. With other kinds of transitions, theoretical approaches combining epidemiology and population genetics are providing guidelines for determining when and how rapidly new transmission modes may evolve, but these are still in need of empirical investigation and application to particular cases. Obtaining such knowledge is a matter of urgency in relation to extant disease threats. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’. PMID:28289251

  2. Microwave power engineering generation, transmission, rectification

    CERN Document Server

    Okress, Ernest C

    1968-01-01

    Microwave Power Engineering, Volume 1: Generation, Transmission, Rectification considers the components, systems, and applications and the prevailing limitations of the microwave power technology. This book contains four chapters and begins with an introduction to the basic concept and developments of microwave power technology. The second chapter deals with the development of the main classes of high-power microwave and optical frequency power generators, such as magnetrons, crossed-field amplifiers, klystrons, beam plasma amplifiers, crossed-field noise sources, triodes, lasers. The third

  3. Transmission Line Series Compensation for Wind Energy Transmission

    International Nuclear Information System (INIS)

    Palanichamy, C; Wong, Y C

    2015-01-01

    Wind energy has demonstrated to be a clean, copious and absolutely renewable source of energy, and the large penetration of it into the power grid indicates that wind energy is considered an effective means of power generation, Transmission of wind energy from remote locations to load centers necessitates long transmission lines. Series compensation is a proven and economical transmission solution to address system power transfer strength, grid stability, and voltage profile issues of long transmission lines. In this paper, a programmable approach to determine the capacitive reactance of series capacitor and optimum location for its placement to achieve maximum power transfer gas been presented. The respective program with sample solutions has been provided for real-time applications. (paper)

  4. Skin Barrier Function and Allergens

    DEFF Research Database (Denmark)

    Engebretsen, Kristiane Aasen; Thyssen, Jacob Pontoppidan

    2016-01-01

    and skin barrier status. Psoriasis has traditionally been regarded a Th1-dominated disease, but the discovery of Th17 cells and IL-17 provides new and interesting information regarding the pathogenesis of the disease. Research suggests an inverse relationship between psoriasis and CA, possibly due......The skin is an important barrier protecting us from mechanical insults, microorganisms, chemicals and allergens, but, importantly, also reducing water loss. A common hallmark for many dermatoses is a compromised skin barrier function, and one could suspect an elevated risk of contact sensitization...... to increased levels of Th17 cells and its associated cytokines. As for AD, a positive association to CS has been established in epidemiological studies, but is still unresolved. Experimental studies show, however, an inverse relationship between AD and CS. The opposing and antagonistic influences of Th1 (CS...

  5. The critical role of the barrier thickness in spin filter tunneling

    International Nuclear Information System (INIS)

    Miller, Casey W.

    2009-01-01

    Spin filter tunneling is considered in the low bias limit as functions of the temperature dependent barrier parameters. We demonstrate the generation of spin polarized tunneling currents in relation to the magnetic order parameter, and discuss how an interfacially suppressed order parameter leads to a temperature dependent tunneling current asymmetry. Analyzing the full parameter space reveals that the often overlooked barrier thickness plays a critical role in spin filter tunneling. With all else fixed, thicker barriers yield higher spin polarization, and allow a given polarization to be achieved at higher temperatures. This insight may open the door for new materials to serve as spin filter barriers.

  6. The evolution of plant virus transmission pathways

    Science.gov (United States)

    Frédéric M. Hamelin; Linda J.S. Allen; Holly R. Prendeville; M. Reza Hajimorad; Michael J. Jeger

    2016-01-01

    The evolution of plant virus transmission pathways is studied through transmission via seed, pollen, oravector. We address the questions: under what circumstances does vector transmission make pollen transmission redundant? Can evolution lead to the coexistence of multiple virus transmission pathways? We restrict the analysis to an annual plant population in which...

  7. Analytics on Transmission Electron Microscopy

    International Nuclear Information System (INIS)

    Keum, Dong Hwa; Kim, Geung Ho; Lee, Hwak Ju and others

    1996-06-01

    This book gives descriptions of transmission electron microscopy, which deals with electron microscopy and materials science, history of electron microscopy, application of analytics on transmission electron microscopy, machine requirement of transmission electron microscopy like electron gun and TEM image and function, crystal diffraction, electron diffraction, Kikuchi's diffraction figure, analysis of diffraction figure, contrast of TEM image like absorption contrast, and phase contrast, Fresnel's diffraction and TEM contrast, thickness fringe, column approximation, analysis of diffraction contrast, image simulation, and electron energy loss spectrometry.

  8. Schistosomiasis transmission in Lake Malawi

    DEFF Research Database (Denmark)

    Madsen, H.; Stauffer, J. R.; Bloch, P.

    2004-01-01

    Schistosomiasis (bilharziasis) transmission due to Schistosoma haematobium has for many years been known to occur along protected shorelines in Lake Malawi, but the recent finding that transmission also can also occur along open shorelines with sandy sediment has had a detrimental effect on tourism...... to Lake Malawi. The present paper shows that transmission, as evidenced from presence of intermediate hosts, along open shorelines is occurring in the southern part of the Lake. Relatively simple precautions can be taken to ensure minimal risk of attracting schistosome infection, and the schistosomiasis...

  9. Midwest Transmission Workshop I Summary

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Bryan

    2001-05-01

    OAK-B135 The meeting was opened with a review of the purposes of the workshop: (1) Present and discuss key studies and assessments of transmission upgrades, additions and related issues for the upper Midwest, including work that addresses the full range of views on these topics; (2) Understand the various transmission issues in the upper Midwest and discuss options for addressing the issues; and (3) Identify the decision makers and entities that need to play an active role if transmission issues are to be resolved, and agree on next steps for engaging these individuals and organizations through education, outreach, and information dissemination.

  10. Markets for financial transmission rights

    International Nuclear Information System (INIS)

    Kristiansen, T.

    2004-01-01

    Results of a survey of markets for financial transmission rights that facilitate competitive, open and non-discriminatory electricity market design are discussed. Specifically, the survey covered Pennsylvania, New Jersey, Maryland (PJM), New York, California, New England, Texas and New Zealand. The main emphasis was on the PJM and the New York markets, since they are the most mature. Interwowen with the results is a thorough discussion of the properties, features and the design of financial transaction rights in the various jurisdictions, the advantages, disadvantages and market performance of financial transmission rights, market performance criteria, and the mechanism for acquiring financial transmission rights. 49 refs., 14 tabs., 6 figs

  11. Geotechnical assessments of upgrading power transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Andrew [Coffey Geotechnics Ltd., Harrogate (United Kingdom)

    2012-11-01

    One of the consequences of increasing demand for energy is a corresponding requirement for increased energy distribution. This trend is likely to be magnified by the current tendency to generate power in locations remote from centres of population. New power transmission routes are expensive and awkward to develop, and there are therefore benefits to be gained by upgrading existing routes. However, this in turn raises problems of a different nature. The re-use of any structure must necessarily imply the acceptance of unknowns. The upgrading of transmission lines is no exception to this, particularly when assessing foundations, which in their nature are not visible. A risk-based approach is therefore used. This paper describes some of the geotechnical aspects of the assessment of electric power transmission lines for upgrading. It briefly describes the background, then discusses some of the problems encountered and the methods used to address them. These methods are based mainly on information obtained from desk studies and walkover surveys, with a limited amount of intrusive investigation. (orig.)

  12. Symmetric fusion of heavy ions around the Coulomb barrier energy

    International Nuclear Information System (INIS)

    Royer, G.; Remaud, B.

    1983-01-01

    Using the liquid drop model, we have performed a systematic study of the symmetric fusion with a neck degree of freedom and tunnelling effects, the nuclear potential being calculated with the proximity approach. Barrier heights and positions are in very good agreement with experimental data when they are known (light-medium systems); the recent experimental data of the reactions 58 Ni + 58 Ni and 64 Ni + 64 Ni are particularly investigated. For heavier systems double-humped fusion barriers and isomeric states are predicted which strongly limit the complete fusion probability

  13. Barriers and Opportunities for Sustainable Food Systems in Northeastern Kansas

    Directory of Open Access Journals (Sweden)

    Rhonda Janke

    2010-01-01

    Full Text Available Survey responses of producers and institutional buyers in northeastern Kansas (United States were analyzed to understand barriers and opportunities for sustainable food systems in the region where their emergence has been limited. Producers and buyers identified barriers previously noted regarding mismatches of available quantities and prices. Producers’ enthusiasm to supply locally exceeded buyers’ interest to source locally. Transportation was identified as one of the major concerns by producers, and their responses to choice tasks revealed producers’ preferences to sell locally while pricing their products to secure sales revenue and to cover their logistics expenses at least partially.

  14. Viscosity-Induced Crossing of the Phantom Barrier

    Directory of Open Access Journals (Sweden)

    Iver Brevik

    2015-09-01

    Full Text Available We show explicitly, by using astrophysical data plus reasonable assumptions for the bulk viscosity in the cosmic fluid, how the magnitude of this viscosity may be high enough to drive the fluid from its position in the quintessence region at present time t = 0 across the barrier w = −1 into the phantom region in the late universe. The phantom barrier is accordingly not a sharp mathematical divide, but rather a fuzzy concept. We also calculate the limiting forms of various thermodynamical quantities, including the rate of entropy production, for a dark energy fluid near the future Big Rip singularity.

  15. Microstability of TMX-U during initial thermal barrier operation

    International Nuclear Information System (INIS)

    Casper, T.A.; Berzins, L.V.; Ellis, R.F.; James, R.A.; Lasnier, C.

    1984-03-01

    During the initial thermal barrier experiments on the Tandem Mirror Experiment-Upgrade (TMX-U), we successfully demonstrated the principle of improved axial tandem mirror confinement achieved by establishment of both the thermal barrier and the ion confining potential peak. During this operation, we created both hot (100-keV) mirror-confined electron and hot (8-keV) mirror-confined ion populations in the end cells. In certain parameter ranges, we observed these species to be weakly unstable to various microinstabilities, but we did not observe clear evidence for an absolute limit to confinement

  16. Intertwined arbovirus transmission activity: reassessing the transmission cycle paradigm.

    Directory of Open Access Journals (Sweden)

    Luis Adrian Diaz

    2013-01-01

    Full Text Available Arboviruses are emerging/reemerging infectious agents worldwide. The factors within this scenario include vector and host population fluctuations, climatic changes, anthropogenic activities that disturb ecosystems, an increase in international flights, human mobility, and genetic mutations that allow spill-over phenomenon. Arboviruses are maintained by biologic transmission among vectors and hosts. Sometimes this biological transmission is specific and includes one vector and host species such as CHK, DEN and urban YFV. However, most of the arboviruses are generalist and they use many vectors and hosts species. From this perspective, arboviruses are maintained through a transmission network rather than a transmission cycle. This allows us to understand the complexity and dynamics of the transmission and maintenance of arboviruses in the ecosystems. The old perspective that arboviruses are maintained in close and stable transmission cycles should be modified by a new more integrative and dynamic idea, representing the real scenario where biological interactions have a much broader representation, indicating the constant adaptability of the biological entities.

  17. Barrier mechanisms in the Drosophila blood-brain barrier.

    Science.gov (United States)

    Hindle, Samantha J; Bainton, Roland J

    2014-01-01

    The invertebrate blood-brain barrier (BBB) field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through G-protein coupled receptor signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate BBB has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many BBB mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the BBB can govern whole animal physiologies. This includes novel functions of BBB gap junctions in orchestrating synchronized neuroblast proliferation, and of BBB secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate BBB anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.

  18. Communication barriers in the family

    Directory of Open Access Journals (Sweden)

    BARBARA KOC-KOZŁOWIEC

    2017-10-01

    Full Text Available The art of communication – listening and speaking – is a major life skill, with a thorough influence on every human life. Remaining silent while the interlocutor speaks is not all that there is to the act of listening to messages. True listening is based on an intention to get involved in understanding of the other person, enjoying his or her presence, learning something from the conversation, giving assistance, or comforting the interlocutor. In the article the author describes obstacles (barriers, which render true listening impossible. These barriers have been identified by a group of young adults.

  19. Social Barriers to Effective Communication in Old Age

    Directory of Open Access Journals (Sweden)

    Anna Sanecka

    2014-12-01

    Full Text Available Some communication barriers apply particularly to elderly people. The social barriers to effective communication in old age are the barriers caused by stereotypes of old age/elderly people and the barriers arising from limitations in using mass communication by seniors. Stereotypes of old age/elderly people embrace views regarding old people’s communication skills and the ideas about the correct way of communication with them. Therefore the communication problems of old people are correlated with the little and poor communication processes they are participating in. This seems to be a result of impetuses of poor quality sent to seniors by their communication partners. Not only face to face communication but also mass communication is very important for the elderly population. Therefore limitations in using new technologies and new communication channels as well as a limited presence in the mass media of content created by seniors and for seniors have an impact on their life, their well-being, and their interpersonal relationships. These problems are especially important when we faced with the ever growing population of elderly people.

  20. Transmission investment problems in Europe: Going beyond standard solutions

    International Nuclear Information System (INIS)

    Buijs, Patrik; Bekaert, David; Cole, Stijn; Van Hertem, Dirk; Belmans, Ronnie

    2011-01-01

    The European transmission grid is facing an investment challenge. There is a strong call for more transmission capacity. At the same time, the investment climate is fierce and troubled by public opposition, a complex regulatory framework, etc. Many transmission capacity expansion projects are delayed or canceled. In this paper different technology options suitable for increasing transmission capacity are discussed. The aim is to provide policy-makers with information on technologies without going too much into technical details. The focus is on opportunities and limitations to implement various technological alternatives in practice, including technical solutions that go beyond constructing new connection lines. The criteria used in this technology assessment are based on the obstacles reported in the European Priority Interconnection Plan. This ensures a realistic approach based on problems encountered in real projects. Although AC overhead lines (OHL) will remain the standard solution for grid expansion, it is argued that different technology options can overcome many obstacles that OHL face. Additionally, it is illustrated that the higher investment costs for some solutions can be offset with an increased benefit, e.g. by accomplishing investments with smaller delays due to fewer obstacles encountered. - Research highlights: → Assessment of real problems encountered in transmission investments. → Comparison of transmission technologies. → Techno-economic evaluation of transmission technologies.

  1. Chagas disease transmission by consumption of game meat: systematic review.

    Science.gov (United States)

    Sangenis, Luiz Henrique Conde; Nielebock, Marco Antonio Prates; Santos, Ceumara da Silva; Silva, Mateus Curty Carriello da; Bento, Glauber Motta Ribeiro

    2016-01-01

    To evaluate the influence of game meat consumption in Chagas disease (CD) transmission, the conditions under which it occurs and the frequency of reports in the literature. Through systematic review, databases PubMed, LILACS, MEDLINE, and SciELO were consulted, and articles written in Portuguese, English, and Spanish were included, with no limitation over publication date. We used the following descriptors: oral, transmission, meat, wild animals, hunt, carnivory, and Chagas disease. Articles that mentioned consumption of animal meat as a form of human transmission of CD were included. We used epidemiological, clinical, and laboratory evidence criteria to confirm cases. Among the 298 articles identified, only six met the eligibility criteria. Only five episodes of oral transmission through wild animal meat or blood consumption were identified. However, in two of them, the possibility of vectorial transmission could not be ruled out. Most reports met the epidemiological, clinical, and laboratory evidence criteria established to support the transmission. Though CD transmission is uncommon, hunting and consumption of wild mammals that serve as Trypanosoma cruzi reservoirs should be discouraged in endemic countries in light of the risks inherent to these practices.

  2. Impacts of Demand-Side Resources on Electric Transmission Planning

    Energy Technology Data Exchange (ETDEWEB)

    Hadley, Stanton W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sanstad, Alan H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-01-01

    Will demand resources such as energy efficiency (EE), demand response (DR), and distributed generation (DG) have an impact on electricity transmission requirements? Five drivers for transmission expansion are discussed: interconnection, reliability, economics, replacement, and policy. With that background, we review the results of a set of transmission studies that were conducted between 2010 and 2013 by electricity regulators, industry representatives, and other stakeholders in the three physical interconnections within the United States. These broad-based studies were funded by the US Department of Energy and included scenarios of reduced load growth due to EE, DR, and DG. While the studies were independent and used different modeling tools and interconnect-specific assumptions, all provided valuable results and insights. However, some caveats exist. Demand resources were evaluated in conjunction with other factors, and limitations on transmission additions between scenarios made understanding the role of demand resources difficult. One study, the western study, included analyses over both 10- and 20-year planning horizons; the 10-year analysis did not show near-term reductions in transmission, but the 20-year indicated fewer transmission additions, yielding a 36percent capital cost reduction. In the eastern study the reductions in demand largely led to reductions in local generation capacity and an increased opportunity for low-cost and renewable generation to export to other regions. The Texas study evaluated generation changes due to demand, and is in the process of examining demand resource impacts on transmission.

  3. Bottlenecks reduction using superconductors in high voltage transmission lines

    Directory of Open Access Journals (Sweden)

    Daloub Labib

    2016-01-01

    Full Text Available Energy flow bottlenecks in high voltage transmission lines known as congestions are one of the challenges facing power utilities in fast developing countries. Bottlenecks occur in selected power lines when transmission systems are operated at or beyond their transfer limits. In these cases, congestions result in preventing new power supply contracts, infeasibility in existing contracts, price spike and market power abuse. The “Superconductor Technology” in electric power transmission cables has been used as a solution to solve the problem of bottlenecks in energy transmission at high voltage underground cables and overhead lines. The increase in demand on power generation and transmission happening due to fast development and linked to the intensive usage of transmission network in certain points, which in turn, lead to often frequent congestion in getting the required power across to where it is needed. In this paper, a bottleneck in high voltage double overhead transmission line with Aluminum Conductor Steel Reinforced was modeled using conductor parameters and replaced by Gap-Type Superconductor to assess the benefit of upgrading to higher temperature superconductor and obtain higher current carrying capacity. This proved to reduce the high loading of traditional aluminum conductors and allow more power transfer over the line using superconductor within the same existing right-of-way, steel towers, insulators and fittings, thus reducing the upgrade cost of building new lines.

  4. Edge Detection and Shape Recognition in Neutron Transmission Images

    International Nuclear Information System (INIS)

    Sword, Eric D.; McConchie, Seth M.

    2012-01-01

    Neutron transmission measurements are a valuable tool for nondestructively imaging special nuclear materials. Analysis of these images, however, tends to require significant user interaction to determine the sizes, shapes, and likely compositions of measured objects. Computer vision (CV) techniques can be a useful approach to automatically extracting important information from either neutron transmission images or fission-site-mapping images. An automatable approach has been developed that processes an input image and, through recursive application of CV techniques, produces a set of basic shapes that define surfaces observed in the image. These shapes can then be compared to a library of known shape configurations to determine if the measured object matches its expected configuration, as could be done behind an information barrier for arms control treaty verification inspections.

  5. AIDS-related stigma, HIV testing, and transmission risk among patrons of informal drinking places in Cape Town, South Africa.

    Science.gov (United States)

    Pitpitan, Eileen V; Kalichman, Seth C; Eaton, Lisa A; Cain, Demetria; Sikkema, Kathleen J; Skinner, Donald; Watt, Melissa H; Pieterse, Desiree

    2012-06-01

    AIDS-related stigma as a barrier to HIV testing has not been examined within the context of high at risk environments such as drinking venues. Of particular importance is whether AIDS-related stigma is associated with HIV transmission risks among people who have never been tested for HIV. We examined: (1) AIDS-related stigma as a barrier to testing, controlling for other potential barriers, and (2) whether stigma is associated with HIV risks among HIV-untested individuals. We surveyed 2,572 individuals attending informal drinking establishments in Cape Town, South Africa to assess HIV testing status, AIDS-related stigma endorsement, and HIV transmission sexual risk behavior. Endorsement of AIDS-related stigma was negatively associated with HIV lifetime testing. In addition, stigma endorsement was associated with higher HIV transmission risks. AIDS-related stigma must be addressed in HIV prevention campaigns across South Africa. Antistigma messages should be integrated with risk reduction counseling and testing.

  6. Design and performance evaluation of a 1000-year evapotranspiration-capillary surface barrier

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhuanfang Fred; Strickland, Christopher E.; Link, Steven O.

    2017-02-01

    Surface barrier technology is used to isolate radioactive waste and to reduce or eliminate recharge water to the waste zone for 1000 years or longer. However, the design and evaluation of such a barrier is challenging because of the extremely long design life. The Prototype Hanford Barrier (PHB) was designed as a 1000-year barrier with pre-determined design and performance objectives and demonstrated in field from 1994 to present. The barrier was tested to evaluate surface-barrier design and performance at the field scale under conditions of enhanced and natural precipitation and of no vegetation. The monitoring data demonstrate that the barrier satisfied nearly all key objectives. The PHB far exceeded the Resource Conservation and Recovery Act criteria, functioned in Hanford’s semiarid climate, limited drainage to well below the 0.5 mm yr-1 performance criterion, limited runoff, and minimized erosion. Given the two-decade record of successful performance and consideration of all the processes and mechanisms that could degrade the stability and hydrology in the future, the results suggest the PHB is very likely to perform for its 1000-year design life. This conclusion is based on two assumptions: (1) the exposed subgrade receives protection against erosion and (2) institutional controls prevent inadvertent human activity at the barrier. The PHB design can serve as the base for site-specific barriers over waste sites containing underground nuclear waste, uranium mine tailings, and hazardous mine waste.

  7. Systems study on engineered barriers: barrier performance analysis

    International Nuclear Information System (INIS)

    Stula, R.T.; Albert, T.E.; Kirstein, B.E.; Lester, D.H.

    1980-09-01

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed

  8. Systems study on engineered barriers: barrier performance analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stula, R.T.; Albert, T.E.; Kirstein, B.E.; Lester, D.H.

    1980-09-01

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed.

  9. Contribution à l’optimisation des systèmes de transmission optiques cohérents (Nx100 Gbit/s) utilisant le multiplexage en polarisation par des formats de modulation en phase et une conception de ligne limitant l’impact des effets non-linéaires

    OpenAIRE

    Seck, Aida

    2014-01-01

    The ever-increasing demand of capacity in very high bit rate coherent optical transmission systems has paved the way towards the investigation of several techniques such as the use of ultra-low loss fibers, Erbium doped fiber amplifiers, polarization and wavelength division multiplexing (WDM), coherent detection, multi-level modulation formats, spatial division multiplexing, etc. However, there are questions concerning polarization division multiplexing and a development towards some advanced...

  10. Rumor propagation with heterogeneous transmission in social networks

    Science.gov (United States)

    Vega-Oliveros, Didier A.; Costa, Luciano da F.; Rodrigues, Francisco A.

    2017-02-01

    Rumor models consider that information transmission occurs with the same probability between each pair of nodes. However, this assumption is not observed in social networks, which contain influential spreaders. To overcome this limitation, we assume that central individuals have a higher capacity to convince their neighbors than peripheral subjects. From extensive numerical simulations we find that spreading is improved in scale-free networks when the transmission probability is proportional to the PageRank, degree, and betweenness centrality. In addition, the results suggest that spreading can be controlled by adjusting the transmission probabilities of the most central nodes. Our results provide a conceptual framework for understanding the interplay between rumor propagation and heterogeneous transmission in social networks.

  11. Transmission Reinforcements in the Central American Regional Power System

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo, Marcelo A.; Vallem, Mallikarjuna R.; Samaan, Nader A.; Makarov, Yuri V.; Vyakaranam, Bharat; Nguyen, Tony B.; Munoz, Christian; Herrera, Ricardo; Midence, Diego; Shpitsberg, Anna

    2016-07-25

    The Central American regional interconnected power system (SER) connects the countries members of the Central American regional electricity market (MER): Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, and Panama. The SER was a result of a long term regional effort, and was initially conceived to transfer 300 MW between countries. However, the current transfer limits between countries range from 70 MW to 300 MW. Regional entities, like CRIE (Regional Commission of Electrical Interconnection), EOR (Central American Regional System Operator), and CDMER (Board of Directors of the Central American Market) are working on coordinating the national transmission expansion plans with regional transmission planning efforts. This paper presents experience in Central America region to recommend transmission reinforcements to achieve 300 MW transfer capacity between any pair of member countries of the Central American regional electricity market (MER). This paper also provides a methodology for technical analysis and for coordination among the regional and national entities. This methodology is unique for transmission systems of these characteristics.

  12. Non-iridescent transmissive structural color filter featuring highly efficient transmission and high excitation purity.

    Science.gov (United States)

    Shrestha, Vivek Raj; Lee, Sang-Shin; Kim, Eun-Soo; Choi, Duk-Yong

    2014-05-12

    Nanostructure based color filtering has been considered an attractive replacement for current colorant pigmentation in the display technologies, in view of its increased efficiencies, ease of fabrication and eco-friendliness. For such structural filtering, iridescence relevant to its angular dependency, which poses a detrimental barrier to the practical development of high performance display and sensing devices, should be mitigated. We report on a non-iridescent transmissive structural color filter, fabricated in a large area of 76.2 × 25.4 mm(2), taking advantage of a stack of three etalon resonators in dielectric films based on a high-index cavity in amorphous silicon. The proposed filter features a high transmission above 80%, a high excitation purity of 0.93 and non-iridescence over a range of 160°, exhibiting no significant change in the center wavelength, dominant wavelength and excitation purity, which implies no change in hue and saturation of the output color. The proposed structure may find its potential applications to large-scale display and imaging sensor systems.

  13. Enhancement of seeding for electroless Cu plating of metallic barrier layers by using alkyl self-assembled monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Sung-Te [Department of Electronic Engineering, Hsiuping University of Science and Technology, Dali 412, Taichung, Taiwan (China); Chung, Yu-Cheng [Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan (China); Fang, Jau-Shiung [Department of Materials Science and Engineering, National Formosa University, Huwei 632, Taiwan (China); Cheng, Yi-Lung [Department of Electrical Engineering, National Chi-Nan University, Puli, Nantou 545, Taiwan (China); Chen, Giin-Shan, E-mail: gschen@fcu.edu.tw [Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan (China)

    2017-05-31

    Highlights: • Ta barrier layers are used as model substrates for seeding of electroless plating. • Ta layers seeded with Ta-OH yield seeds with limited density and large size (>10 nm). • Substantial improvement of seeding is obtained with functionalized SAMs. • The mechanism of seeding improvement by functionalized SAMs is clearly clarified. - Abstract: Tethering a self-assembled monolayer (SAM) on ultralow-k (porous) dielectric materials as a seed-trapping layer for electroless Cu plating has been extensively studied. By contrast, literature on direct electroless Cu plating of metallic barrier layers assisted by SAMs is scarce. Therefore, Ta, a crucial component of barrier materials for Cu interconnect metallization, was investigated as a model substrate for a new seeding (Ni catalyst formation) process of electroless Cu plating. Transmission and scanning electron microscopies indicated that catalytic particles formed on Ta films through Ta−OH groups tend to become aggregates with an average size of 14 nm and density of 2 × 10{sup 15} m{sup −2}. By contrast, Ta films with a plasma-functionalized SAM tightly bound catalytic particles without agglomeration, thus yielding a markedly smaller size (3 nm) and higher density (3 × 10{sup 16} m{sup −2}; one order greater than those formed by other novel methods). X-ray photoelectron spectroscopy clearly identified the types of material species and functional groups induced at each step of the seeding process. Moreover, the phase of the catalytic particles, either nickel alkoxide, Ni(OH){sub 2}, or metallic Ni, along with the seed-bonding mechanism, was also unambiguously distinguished. The enhancement of film-formation quality of Cu by the new seeding process was thus demonstrated.

  14. Accounting-related transmission issues

    International Nuclear Information System (INIS)

    Niehaus, M.; Bjorn, P.; Pate, G.

    1999-01-01

    Various initiatives have been undertaken by the Federal Energy Regulatory Commission (FERC) to deregulate wholesale electric energy markets. These initiatives have focused on restructuring the transmission systems in the US and recently have culminated in a proposal requiring formation of and participation in regional transmission organizations. The overall form of regulation selected to determine rates for transmission entities as well as underlying regulatory decisions reached on key issues will have profound implications for transmission entities. For example, traditional cost-based regulation would require one set of accounting and reporting rules, while incentive-based regulation may not be subject to those same rules. An overview of some of the major accounting and financial reporting issues that will need to be considered is presented

  15. Fomite transmission in head lice.

    Science.gov (United States)

    Burkhart, Craig N; Burkhart, Craig G

    2007-06-01

    Control of various infestations requires an accurate understanding of transmission. After thousands of years of lice infestation, scientific documentation of indirect contact transmission has been substantiated. Lice can be transferred in the egg, instar, and adult stages. Lice have now been shown in the laboratory to be readily dislodged by air movements such as blow-drying one's hair, combing, and toweling. Moreover, passive transfer to adjoining fabric is also frequently observed. Louse transmission by fomites occurs more frequently than has been commonly believed. Close proximity suffices to increase the likeliness of a new infestation. Thus louse control measures should take account of fomite transmission and include screening of all individuals within an infested person's immediate circle of contact, laundering of everything within the infested individuals' bed or quarantining of such material for 10 days, thorough vacuuming of floors, carpets, upholstery, with a standard vacuum cleaner.

  16. Oral transmission of Chagas disease.

    Science.gov (United States)

    Shikanai-Yasuda, Maria Aparecida; Carvalho, Noemia Barbosa

    2012-03-01

    Chagas disease is now an active disease in the urban centers of countries of nonendemicity and endemicity because of congenital and blood and/or organ transplantation transmissions and the reactivation of the chronic disease in smaller scale than vectorial transmission, reported as controlled in countries of endemicity. Oral transmission of Chagas disease has emerged in unpredictable situations in the Amazon region and, more rarely, in areas of nonendemicity where the domiciliary triatomine cycle was under control because of exposition of the food to infected triatomine and contaminated secretions of reservoir hosts. Oral transmission of Chagas disease is considered when >1 acute case of febrile disease without other causes is linked to a suspected food and should be confirmed by the presence of the parasite after direct microscopic examination of the blood or other biological fluid sample from the patient.

  17. Echinococcosis : disease, detection and transmission

    NARCIS (Netherlands)

    Craig, P.S.; Rogan, M T; Campos-Ponce, M

    2003-01-01

    Echinococcosis is one of the world's most geographically widespread parasitic zoonoses, with transmission occurring in tropical, temperate and arctic biomes. Most human infections are due to Echinococcus granulosus transmitted between domestic dogs and livestock, but this cosmopolitan species also

  18. Radio and line transmission 2

    CERN Document Server

    Roddy, Dermot

    2013-01-01

    Radio and Line Transmission, Volume 2 gives a detailed treatment of the subject as well as an introduction to additional advanced subject matter. Organized into 14 chapters, this book begins by explaining the radio wave propagation, signal frequencies, and bandwidth. Subsequent chapters describe the transmission lines and cables; the aerials; tuned and coupled circuits; bipolar transistor amplifiers; field-effect transistors and circuits; thermionic valve amplifiers; LC oscillators; the diode detectors and modulators; and the superheterodyne receiver. Other chapters explore noise and interfere

  19. Cardinality of UDP Transmission Outcomes

    OpenAIRE

    Weitl, Franz; Sebih, Nazim; Artho, Cyrille; Hagiya, Masami; Tanabe, Yoshinori; Yamagata, Yoriyuki; Yamamoto, Mitsuharu

    2015-01-01

    This paper examines the cost of testing network applications using the User Datagram Protocol (UDP). Such applications must deal with packet loss, duplication, and reordering. Ideally, a UDP application should be tested against all possible outcomes of unreliable UDP transmissions. Their number, however, grows at least exponentially in the number of transmitted packets. To estimate the cost of the exhaustive testing of UDP applications, we determine the number of UDP transmission outcomes ana...

  20. Heartland Alliance for Regional Transmission

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Nancy [Climate and Energy Project, Inc., Hutchinson, KS (United States)

    2017-03-15

    The Heartland Alliance for Regional Transmission (HART) will foster a candid, productive conversation among stakeholders that identifies challenges to and benefits from a massive build out of wind generation and transmission across the Southwest Power Pool. Based on the outcomes of those deliberations, HART will develop and deliver an ambitious, coordinated, peer-to-peer outreach effort that spans the SPP to improve market acceptance for wind.